毕业论文(设计)外文文献翻译及原文
隧道盾构-毕设论文外文翻译(翻译-原文)
毕业设计（论文）外文文献翻译院系：土木工程与建筑系年级专业：土木工程姓名：学号：附件：盾构SHIELDS指导老师评语：指导教师签名：年月日S HIEL D S【Abstr act】A tunnel shield is a structural system, used during the face excavation process. The paper mainly discusses the form and the structure of the shield. Propulsion for the shield is provided by a series of hydraulic jacks installed in the tail of the shield and the shield is widespread used in the underground environment where can not be in long time stable. The main enemy of the shield is ground pressure. Non-uniform ground pressure caused by the steering may act on the skin tends to force the shield off line and grade. And working decks inside the shield enable the miners to excavate the face, drill and load holes.【Keywor ds】shield hydraulic jacks ground pressure steering working decksA tunnel shield is a structural system, normally constructed of steel, used during the face excavation process. The shield has an outside configuration which matches the tunnel. The shield provides protection for the men and equipment and also furnished initial ground support until structural supports can be installed within the tail section of the shield. The shield also provides a reaction base for the breast-board system used to control face movement. The shield may have either an open or closed bottom. In a closed-bottom shield, the shield structure and skin provide 360-degree ground contact and the weight of the shield rests upon the invert section of the shield skin. The open shield has no bottom section and requires some additional provision is a pair of side drifts driven in advance of shield excavation. Rails or skid tracks are installed within these side drifts to provide bearing support for the shield.Shield length generally varies from1/2 to 3/4 of the tunnel diameter. The front of the shield is generally hooded to so that the top of the shield protrudes forward further than the invert portion which provides additional protection for the men working at the face and also ease pressure on the breast-boards. The steel skin of the shield may varyfrom 1.3 to 10 cm in thickness, depending on the expected ground pressures. The type of steel used in the shield is the subject of many arguments within the tunneling fraternity. Some prefer mild steel in the A36 category because of its ductility and case of welding in the underground environment where precision work is difficult. Others prefer a high-strength steel such as T-1 because of its higher strength/w eight ratio. Shield weight may range from 5 to 500 tons. Most of the heaviest shields are found in the former Sovier Union because of their preference for cast-iron in both structural and skin elements.Propulsion for the shield is provided by a series of hydraulic jacks installed in the tail of the shield that thrust against the last steel set that has been installed. The total required thrust will vary with skin area and ground pressure. Several shields have been constructed with total thrust capabilities in excess of 10000 tons. Hydraulic systems are usually self-contained, air-motor powered, and mounted on the shield. Working pressures in the hydraulic system may range from 20-70 Mpa. To resist the thrust of the shield jacks, a horizontal structure member (collar brace) must be installed opposite each jack location and between the flanges of the steel set. In addition, some structural provision must be made for transferring this thrust load into the tunnel walls. Without this provision the thrust will extend through the collar braces to the tunnel portal.An Englishman, Marc Brunel, is credited with inventing the shield. Brunel supposedly got his idea by studying the action of the Teredo navalis, a highly destructive woodworm, when he was working at the Chatham dock yard. In 1818 Brunel obtained an English patent for his rectangular shield which was subsequently uses to construct the first tunnel under the River Thames in London. In 1869 the first circular shield was devised by Barlow and Great Head in London and is referred to as the Great Head-type shield. Later that same year, Beach in New York City produced similar shield. The first use of the circular shield came during 1869 when Barlow and Great Head employed their device in the construction of the 2.1 in diameter Tower Subway under the River Thames. Despite the name of the tunnel, it was used only for pedestrian traffic. Beach also put his circular shield to work in 1869 to construct a demonstration project for a proposed NewYork City subway system. The project consisted of a 2.4 m diameter tunnel, 90 m long, used to experiment with a subway car propelled by air pressure.Here are some tunnels which were built by shield principle.Soft-ground tunneling Some tunnels are driven wholly or mostly through soft material. In very soft ground, little or no blasting is necessary because the material is easily excavated.At first, forepoling was the only method for building tunnels through very soft ground. Forepoles are heavy planks about 1.5 m long and sharpened to a point. They were inserted over the top horizontal bar of the bracing at the face of the tunnel. The forepoles were driven into the ground of the face with an outward inclination. After all the roof poles were driven for about half of their length, a timber was laid across their exposed ends to counter any strain on the outer ends. The forepoles thus provided an extension of the tunnel support, and the face was extended under them. When the ends of the forepoles were reached, new timbering support was added, and the forepoles were driven into the ground for the next advance of the tunneling.The use of compressed air simplified working in soft ground. An airlock was built, though which men and equipment passed, and sufficient air pressure was maintained at the tunnel face to hold the ground firm during excavation until timbering or other support was erected.Another development was the use of hydraulically powered shields behind which cast-iron or steel plates were placed on the circumference of the tunnels. These plates provided sufficient support for the tunnel while the work proceeded, as well as full working space for men in the tunnel.Under water tunneling The most difficult tunneling is that undertaken at considerable depths below a river or other body of water. In such cases, water seeps through porous material or crevices, subjecting the work in progress to the pressure of the water above the tunneling path. When the tunnel is driven through stiff clay, the flow of water may be small enough to be removed by pumping. In more porous ground,compressed air must be used to exclude water. The amount of air pressure that is needed increases as the depth of the tunnel increases below the surface.A circular shield has proved to be most efficient in resisting the pressure of soft ground, so most shield-driven tunnels are circular. The shield once consisted of steel plates and angle supports, with a heavily braced diaphragm across its face. The diaphragm had a number of openings with doors so that workers could excavate material in front of the shield. In a further development, the shield was shoved forward into the silty material of a riverbed, thereby squeezing displaced material through the doors and into the tunnel, from which the muck was removed. The cylindrical shell of the shield may extend several feet in front of the diaphragm to provide a cutting edge. A rear section, called the tail, extends for several feet behind the body of the shield to protect workers. In large shields, an erector arm is used in the rear side of the shield to place the metal support segments along the circumference of the tunnel.The pressure against the forward motion of a shield may exceed 48.8 Mpa. Hydraulic jacks are used to overcome this pressure and advance the shield, producing a pressure of about 245 Mpa on the outside surface of the shield.Shields can be steered by varying the thrust of the jacks from left side to right side or from top to bottom, thus varying the tunnel direction left or right or up or down. The jacks shove against the tunnel lining for each forward shove. The cycle of operation is forward shove, line, muck, and then another forward shove. The shield used about 1955 on the third tube of the Lincoln Tunnel in New York City was 5.5 m long and 9.6 m in diameter. It was moved about 81.2 cm per shove, permitting the fabrication of a 81.2 cm support ring behind it.Cast-iron segments commonly are used in working behind such a shield. They are erected and bolted together in a short time to provide strength and water tightness. In the third tube of the Lincoln Tunnel each segment is 2 m long, 81.2 cm wide, and 35.5 cm thick, and weighs about 1.5 tons. These sections form a ring of 14 segments that are linked together by bolts. The bolts were tightened by hand and then by machine.Immediately after they were in place, the sections were sealed at the joints to ensure permanent water tightness.Shields are most commonly used in ground condition where adequate stand-up time does not exist. The advantage of the shield in this type of ground, in addition to the protection afforded men and equipment , is the time available to install steel ribs, liner plates, or precast concrete segments under the tail segment of the shield before ground pressure and movement become adverse factors.One of the principle problems associated with shield use is steering. Non-uniform ground pressure acting on the skin tends to force the shield off line and grade. This problem is particularly acute with closed bottom shield that do not ride on rails or skid tracks. Steering is accomplished by varying the hydraulic pressure in individual thrust jacks. If the shied is trying to dive, additional pressure on the invert jacks will resist this tendency. It is not unusual to find shield wandering several feet from the required. Although lasers are frequently used to provide continuous line and grade data to operator, once the shield wanders off its course, its sheer bulk resists efforts to bring it back. Heterogeneous ground conditions, such as clay with random boulders, also presents steering problems.One theoretical disadvantage of the shield is the annular space left between the support system and the ground surface. When the support system is installed within the tail section of the shield, the individual support members are separated from the ground surface by the thickness of the tail skin. When steel ribs are used, the annular space is filled with timber blocking as the forward motion of the shield exposes the individual ribs.A continuous support system presents a different problem. In this case, a filler material, such as pea gravel or grout, is pumped behind the support system to fill the void between it and the ground surface.The main enemy of the shield is ground pressure. As ground pressure begins to build, two things happen, more thrust is required for shield propulsion and stress increases in the structural members of the shield. Shields are designed and function undera preselected ground pressure. Designers will select this pressure as a percentage of the maximum ground pressure contemplated by the permanent tunnel design. In some cases, unfortunately, the shield just gets built without specific consideration of the ground pressures it might encounter. When ground pressure exceeds the design limit, the shield gets “stuck”.The friction component of the ground pressure on the skin becomes greater than the thrust capability of the jacks. Several methods, including pumping bentonite slurry into the skin, ground interface, pushing heavy equipment, and bumping with dynamite, have been applied to stuck shields with occasional success.Because ground pressure tends to increase with time, the cardinal rule of operation is “keeping moving”.This accounts for the fracture activity when a shield has suffered a temporary mechanical failure. As ground pressure continues to build on the nonmoving shield , the load finally exceeds its structural limit and bucking begins. An example of shield destruction occurred in California in 1968 when two shields being used to drive the Carly V.Porter Tunnel were caught by excessive ground pressure and deformed beyond repair. One of the Porter Tunnel shields was brought to a halt in reasonably good ground by water bearing ground fault that required full breast-boards. While the contractor was trying to bring the face under control, skin pressure began to increase. While the face condition finally stabilized, the contractor prepared to resume operations and discovered the shield was stuck. No combination of methods was able to move it, and the increasing ground pressure destroyed the shield.To offset the ground pressure effect, a standard provision in design is a cutting edge radius several inches greater than the main body radius. This allows a certain degree o f ground movement before pressure can come to bear on the shield skin. Another approach, considered in theory but not yet put into practice, is the “w atermelon seed”design. The theory calls for a continuous taper in the shield configuration; maximum radius at the cutting edge and the minimum radius at the trailing edge of the tail. With this configuration, any amount of forward movement would create a drop in skin pressure.Working decks, spaced 2.4 to 3.0 m vertically, are provided inside the shield. These working decks enable the miners to excavate the face, drill and load holes, if necessary, and adjust the breast-board system. The hydraulic jacks for the breast-board are mounted on the underside of the work decks. Blast doors are sometimes installed as an integral part of the work decks if a substantial amount of blasting is expected.Some form of mechanical equipment is provided on the rear end of the working decks to assist the miners in handing and placing the element of the support system. In large tunnels, these individual support elements can weigh several tons and mechanical assistance becomes essential. Sufficient vertical clearance must be provided between the invert and the first working deck to permit access to the face by the loading equipment.盾构【摘要】隧道盾构是一结构系统，通常用于洞室开挖。
预应力混凝土Prestressed-Concrete大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：预应力混凝土文献、资料英文题目：Prestressed Concrete文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文资料翻译外文出处：The Concrete structure附件：1、外文原文；2、外文资料翻译译文。
1、外文资料原文Prestressed ConcreteConcrete is strong in compression, but weak in tension: Its tensile strength varies from 8 to 14 percent of its compressive strength. Due tosuch a Iow tensile capacity, fiexural cracks develop at early stages ofloading. In order to reduce or prevent such cracks from developing, aconcentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at thecritical midspan and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections. The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.Such an imposed longitudinal force is called a prestressing force,i.e., a compressive force that prestresses the sections along the span ofthe structural elementprior to the application of the transverse gravitydead and live loads or transient horizontal live loads. The type ofprestressing force involved, together with its magnitude, are determined mainly on the basis of the type of system to be constructed and the span length and slenderness desired.~ Since the prestressing force is applied longitudinally along or parallel to the axis of the member, the prestressing principle involved is commonly known as linear prestressing.Circular prestressing, used in liquid containment tanks, pipes,and pressure reactor vessels, essentially follows the same basic principles as does linear prestressing. The circumferential hoop, or "hugging" stress on the cylindrical or spherical structure, neutralizes the tensile stresses at the outer fibers of the curvilinear surface caused by the internal contained pressure.Figure 1.2.1 illustrates, in a basic fashion, the prestressing action in both types of structural systems and the resulting stress response. In(a), the individual concrete blocks act together as a beam due to the large compressive prestressing force P. Although it might appear that the blocks will slip and vertically simulate shear slip failure, in fact they will not because of the longitudinal force P. Similarly, the wooden staves in (c) might appear to be capable of separating as a result of the high internal radial pressure exerted on them. But again, because of the compressive prestress imposed by the metal bands as a form of circular prestressing, they will remain in place.From the preceding discussion, it is plain that permanent stresses in the prestressed structural member are created before the full dead and live loads are applied in order to eliminate or considerably reduce the net tensile stresses caused by these loads. With reinforced concrete,it is assumed that the tensile strength of the concrete is negligible and disregarded. This is because the tensile forces resulting from the bending moments are resisted bythe bond created in the reinforcement process. Cracking and deflection are therefore essentially irrecoverable in reinforced concrete once the member has reached its limit state at service load.The reinforcement in the reinforced concrete member does not exert any force of its own on the member, contrary to the action of prestressing steel. The steel required to produce the prestressing force in the prestressed member actively preloads the member, permitting a relatively high controlled recovery of cracking and deflection. Once the flexural tensile strength of the concrete is exceeded, the prestressed member starts to act like a reinforced concrete element.Prestressed members are shallower in depth than their reinforced concrete counterparts for the same span and loading conditions. In general, the depth of a prestressed concrete member is usually about 65 to 80 percent of the depth of the equivalent reinforced concrete member. Hence, the prestressed member requires less concrete, and,about 20 to 35 percent of the amount of reinforcement. Unfortunately, this saving in material weight is balanced by the higher cost of the higher quality materials needed in prestressing. Also, regardless of the system used, prestressing operations themselves result in an added cost: Formwork is more complex, since the geometry of prestressed sections is usually composed of. flanged sections with thin-webs.In spite of these additional costs, if a large enough number of precast units are manufactured, the difference between at least the initial costs of prestressed and reinforced concrete systems is usually not very large.~ And the indirect long-term savings are quite substantial, because less maintenance is needed; a longer working life is possible due to better quality control of the concrete, and lighter foundations are achieved due to the smaller cumulative weight of the superstructure.Once the beam span of reinforced concrete exceeds 70 to 90 feet (21.3 to 27.4m), the dead weight of the beam becomes excessive, resulting in heavier members and, consequently, greater long-term deflection and cracking. Thus, for larger spans, prestressed concrete becomes mandatory since arches are expensive to construct and do not perform as well due to the severe long-term shrinkage and creep they undergo.~ Very large spans such as segmental bridges or cable-stayed bridges can only be constructed through the use of prestressing.Prestressd concrete is not a new concept, dating back to 1872, when P. H. Jackson, an engineer from California, patented a prestressing system that used a tie rod to construct beams or arches from individual blocks [see Figure 1.2.1 (a)]. After a long lapse of time during which little progress was made because of the unavailability of high-strength steel to overcome prestress losses, R. E. Dill of Alexandria, Nebraska, recognized the effect of the shrinkage and creep (transverse material flow) of concrete on the loss of prestress. He subsequently developed the idea that successive post-tensioning of unbonded rods would compensate for the time-dependent loss of stress in the rods due to the decrease in the length of the member because of creep and shrinkage. In the early 1920s,W. H. Hewett of Minneapolis developed the principles of circular prestressing. He hoop-stressed horizontal reinforcement around walls of concrete tanks through the use of turnbuckles to prevent cracking due to internalliquid pressure, thereby achieving watertightness. Thereafter, prestressing of tanks and pipes developed at an accelerated pace in the United States, with thousands of tanks for water, liquid, and gas storage built and much mileage of prestressed pressure pipe laid in the two to three decades that followed.Linear prestressing continued to develop in Europe and in France, in particular through the ingenuity of Eugene Freyssinet, who proposed in 1926--1928 methods to overcome prestress losses through the use of high-strength and high-ductility steels. In 1940, he introduced thenow well-known and well-accepted Freyssinet system.P. W. Abeles of England introduced and developed the concept of partial prestressing between the 1930s and 1960s. F. Leonhardt of Germany, V. Mikhailov of Russia, and T. Y. Lin of the United States also contributed a great deal to the art and science of the design of prestressed concrete. Lin's load-balancing method deserves particular mention in this regard, as it considerably simplified the design process, particularly in continuous structures. These twentieth-century developments have led to the extensive use of prestressing throughoutthe world, and in the United States in particular.Today, prestressed concrete is used in buildings, underground structures, TV towers, floating storage and offshore structures, power stations, nuclear reactor vessels, and numerous types of bridge systems including segn~ental and cable-stayed bridges, they demonstrate the versatility of the prestressing concept and its all-encompassing application. The success in the development and construction of all these structures has been due in no small measures to the advances in the technology of materials, particularly prestressing steel, and the accumulated knowledge in estimating the short-and long-term losses in the prestressing forces.~2、外文资料翻译译文预应力混凝土混凝土的力学特性是抗压不抗拉：它的抗拉强度是抗压强度的8％一14％。
毕业设计论文外文文献翻译
毕业设计(论文）外文文献翻译院系：财务与会计学院年级专业：201＊级财务管理姓名:学号：132148*＊*附件: 财务风险管理【Abstract】Although financial risk has increased significantly in recent years risk and risk management are not contemporary issues。
The result of increasingly global markets is that risk may originate with events thousands of miles away that have nothing to do with the domestic market。
Information is available instantaneously which means that change and subsequent market reactions occur very quickly。
The economic climate and markets can be affected very quickly by changes in exchange rates interest rates and commodity prices。
Counterparties can rapidly become problematic。
As a result it is important to ensure financial risks are identified and managed appropriately. Preparation is a key component of risk management。
【Key Words】Financial risk，Risk management，YieldsI. Financial risks arising1.1What Is Risk1.1.1The concept of riskRisk provides the basis for opportunity. The terms risk and exposure have subtle differences in their meaning. Risk refers to the probability of loss while exposure is the possibility of loss although they are often used interchangeably。
(完整版)PLC毕业设计的外文文献(及翻译)
PLC technique discussion and future developmentT.J.byersElectronic Test Equipment-principles and ApplicationsPrinceton University .AmericaAlong with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc, well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person's brain and calculators, with the mode that person's machine combine, for resolve the very complicated problem to look for the best path.We come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only; And the PLC emergence also became the epoch-making topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide.The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipmentsdirect conjunction of the small power can.PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and dates, the ROM can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipments, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold orman-machine interface you knew, it combines with the PLC to our larger space.HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, and the noodles of the usage are wide more and more. The HMI foreground can say that think to be good.At a lot of situations, the list is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick.The PLC correspondence has already come more body now its value, at the PLC and correspondence between Places, can pass the communication of the information and the share of the data’s to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver.The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one pedestal robot to pressthe action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.The form that information transport contain single work, the half a work and the difference of a workers .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phone call is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in canting have an error margins in a dates deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipments, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the long-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc, can use to helps whether the data that we examine to send out have or not themistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contains a string of and combines the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, and 8 differentiations are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the ocular transmission speed is very quick of, it is a string of ocular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to deposited the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind.The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly breaks off is relevant according to various resources of CPU with internal PLC; also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.Each equipment always will not forget a button, it also is at we meet the urgent circumstance use of that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again. Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work. Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety.When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.The PLC still has the function that the high class counts the machine, being us while accept some dates of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwires link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.The development of the higher layer needs our continuous effort to obtain. The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one experience of the generation, coming to the continuous development PLC technique, push it toward higher wave tide.可编程控制器技术讨论与未来发展T.J.拜尔斯（电子测试设备原理及应用普林斯顿大学）随着时代的发展，当今的技术也日趋完善、竞争愈演愈烈；单靠人工的操作已不能满足于目前的制造业前景，也无法保证更高质量的要求和高新技术企业的形象。
过程装备与控制工程专业U形管换热器毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：U形管换热器文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：过程装备与控制工程专业班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文翻译毕业设计（论文）题目： U形管式换热器设计外文题目： U-tube heat exchangers译文题目：指导教师评阅意见U-tube heat exchangersM. Spiga and G. Spiga, Bologna1 Summary:Some analytical solutions are provided to predict the steady temperature distributions of both fluids in U-tube heat exchangers. The energy equations are solved assuming that the fluids remain unmixed and single-phased. The analytical predictions are compared with the design data and the numerical results concerning the heat exchanger of a spent nuclear fuel pool plant, assuming distinctly full mixing and no mixing conditions for the secondary fluid (shell side). The investigation is carried out by studying the influence of all the usual dimensionless parameters (flow capacitance ratio, heat transfer resistance ratio and number of transfer units), to get an immediate and significant insight into the thermal behaviour of the heat Exchanger.More detailed and accurate studies about the knowledge of the fluid temperature distribution inside heat exchangers are greatly required nowadays. This is needed to provide correct evaluation of thermal and structural performances, mainly in the industrial fields (such as nuclear engineering) where larger, more efficient and reliable units are sought, and where a good thermal design can not leave integrity and safety requirements out of consideration [1--3]. In this view, the huge amount of scientific and technical informations available in several texts [4, 5], mainly concerning charts and maps useful for exit temperatures and effectiveness considerations, are not quite satisfactory for a more rigorous and local analysis. In fact the investigation of the thermomechanieal behaviour (thermal stresses, plasticity, creep, fracture mechanics) of tubes, plates, fins and structural components in the heat exchanger insists on the temperature distribution. So it should be very useful to equip the stress analysis codes for heat exchangers withsimple analytical expressions for the temperature map (without resorting to time consuming numerical solutions for the thermal problem), allowing a sensible saving in computer costs. Analytical predictions provide the thermal map of a heat exchanger, aiding in the designoptimization.Moreover they greatly reduce the need of scale model testing (generally prohibitively expensive in nuclear engineering), and furnish an accurate benchmark for the validation of more refined numerical solutions obtained by computer codes. The purpose of this paper is to present the local bulk-wall and fluid temperature distributions forU-tube heat exchangers, solving analytically the energy balance equations.122 General assumptionsLet m, c, h, and A denote mass flow rate (kg/s), specific heat (J/kg -1 K-l), heat transfer coefficient(Wm -2 K-l), and heat transfer surface (m2) for each leg, respectively. The theoretical analysis is based on classical assumptions [6] :-- steady state working conditions,-- equal flow distribution (same mass flow rate for every tube of the bundle),-- single phase fluid flow,-- constant physical properties of exchanger core and fluids,-- adiabatic exchanger shell or shroud,-- no heat conduction in the axial direction,-- constant thermal conductances hA comprehending wall resistance and fouling.According to this last assumption, the wall temperature is the same for the primary and secondary flow. However the heat transfer balance between the fluids is quite respected, since the fluid-wall conductances are appropriately reduced to account for the wall thermal resistance and thefouling factor [6]. The dimensionless parameters typical of the heat transfer phenomena between the fluids arethe flow capacitance and the heat transfer resistance ratiosand the number of transfer units, commonly labaled NTU in the literature,where (mc)min stands for the smaller of the two values (mc)sand (mc)p.In (1) the subscripts s and p refer to secondary and primary fluid, respectively. Only three of the previous five numbers are independent, in fact :The boundary conditions are the inlet temperatures of both fluids3 Parallel and counter flow solutionsThe well known monodimensional solutions for single-pass parallel and counterflow heat exchanger,which will be useful later for the analysis of U-tube heat exchangers, are presented below. If t, T,νare wall, primary fluid, and secondary fluid bulk temperatures (K), and ξ and L represent the longitudinal space coordinate and the heat exchanger length (m), the energy balance equations in dimensionless coordinate x = ξ/L, for parallel and counterflow respectivelyread asM. Spiga and G. Spiga: Temperature profiles in U-tube heat exchangersAfter some algebra, a second order differential equation is deduced for the temperature of the primary (or secondary) fluid, leading to the solutionwhere the integration constants follow from the boundary conditions T(0)=T i , ν(0)≒νifor parallel T(1) = Ti ,ν(0) = νifor counter flow. They are given-- for parallel flow by - for counterflow byWishing to give prominence to the number of transfer units, it can be noticed thatFor counterflow heat exchangers, when E = 1, the solutions (5), (6) degenerate and the fluidtemperatures are given byIt can be realized that (5) -(9) actually depend only on the two parametersE, NTU. However a formalism involving the numbers E, Ns. R has been chosen here in order to avoid the double formalism (E ≤1 and E > 1) connected to NTU.4 U-tube heat exchangerIn the primary side of the U-tube heat exchanger, whose schematic drawing is shown in Fig. 1, the hot fluid enters the inlet plenum flowing inside the tubes, and exits from the outlet plenum. In the secondary side the fluid flows in the tube bundle (shell side). This arrangement suggests that the heat exchanger can be considered as formed by the coupling of a parallel and a counter-flow heat exchanger, each with a heigth equal to the half length of the mean U-tube. However it is necessary to take into account the interactions in the secondary fluid between the hot and the cold leg, considering that the two flows are not physically separated. Two extreme opposite conditions can be investigated: no mixing and full mixing in the two streams of the secondary fluid. The actual heat transfer phenomena are certainly characterized by only a partial mixing ofthe shell side fluid between the legs, hence the analysis of these two extreme theoretical conditions will provide an upper and a lower limit for the actual temperature distribution.4.1 No mixing conditionsIn this hypothesis the U-tube heat exchanger can be modelled by two independent heat exchangers, a cocurrent heat exchanger for the hot leg and a eountercurrent heat exchanger for the cold leg. The only coupling condition is that, for the primary fluid, the inlet temperature in the cold side must be the exit temperature of the hot side. The numbers R, E, N, NTU can have different values for the two legs, because of thedifferent values of the heat transfer coefficients and physical properties. The energy balance equations are the same given in (2)--(4), where now the numbers E and Ns must be changed in E/2 and 2Ns in both legs, if we want to use in their definition the total secondary mass flow rate, since it is reduced in every leg to half the inlet mass flow rate ms. Of course it is understood that the area A to be used here is half of the total exchange area of the unit, as it occurs for the length L too. Recalling (5)--(9) and resorting to the subscripts c and h to label the cold and hot leg, respectively, the temperature profile is given bywhere the integration constants are:M. Spiga and G. Spiga: Temperature profiles in U-tube heat exchangersIf E, = 2 the solutions (13), (14) for the cold leg degenerate into4.2 Full mixing conditionsA different approach can be proposed to predict the temperature distributions in the core wall and fluids of the U-tube heat exchanger. The assumption of full mixing implies that the temperaturesof the secondary fluid in the two legs, at the same longitudinal section, are exactly coinciding. In this situation the steady state energy balance equations constitute the following differential set :The bulk wall temperature in both sides is thenand (18)--(22) are simplified to a set of three equations, whose summation gives a differential equation for the secondary fluid temperature, withgeneral solutionwhere # is an integration constant to be specified. Consequently a second order differential equation is deduced for the primary fluid temperature in the hot leg :where the numbers B, C and D are defined asThe solution to (24) allows to determine the temperaturesand the number G is defined asThe boundary conditions for the fluids i.e. provide the integration constantsAgain the fluid temperatures depend only on the numbers E and NTU.5 ResultsThe analytical solutions allow to deduce useful informations about temperature profiles and effectiveness. Concerning the U-tube heat exchanger, the solutions (10)--(15) and (25)--(27) have been used as a benchmark for the numerical predictions of a computer code [7], already validated, obtaining a very satisfactory agreement.M. Spiga and G. Spiga: Temperature profiles in U-tube heat exchangers 163 Moreover a testing has been performed considering a Shutte & Koerting Co. U-tube heat exchanger, designed for the cooling system of a spent nuclear fuel storage pool. The demineralized water of the fuel pit flows inside the tubes, the raw water in the shell side. The correct determination of the thermal resistances is very important to get a reliable prediction ; for every leg the heat transfer coefficients have been evaluated by the Bittus-Boelter correlation in the tube side [8], by the Weisman correlation in the shell side [9] ; the wall material isstainless steel AISI 304.and the circles indicate the experimental data supplied by the manufacturer. The numbers E, NTU, R for the hot and the cold leg are respectively 1.010, 0.389, 0.502 and 1.011, 0.38~, 0.520. The difference between the experimental datum and the analytical prediction of the exit temperature is 0.7％ for the primary fluid, 0.9% for the secondary fluid. The average exit temperature of the secondary fluid in the no mixing model differs from the full mixing result only by 0.6%. It is worth pointing out the relatively small differences between the profiles obtained through the two different hypotheses (full and no mixing conditions), mainly for the primary fluid; the actual temperature distribution is certainly bounded between these upper and lower limits,hence it is very well specified. Figures 3-5 report the longitudinal temperaturedistribution in the core wall, τw = (t -- νi)/(Ti -- νi), emphasizing theeffects of the parameters E, NTU, R.As above discussed this profile can be very useful for detailed stress analysis, for instance as anM. Spiga and G. Spiga: Temperature profiles in U-tube heat exchangersinput for related computer codes. In particular the thermal conditions at the U-bend transitions are responsible of a relative movement between the hot and the cold leg, producing hoop stresses with possible occurrence of tube cracking . It is evident that the cold leg is more constrained than the hot leg; the axial thermal gradient is higher in the inlet region and increases with increasing values of E, NTU, R. The heat exchanger effectiveness e, defined as the ratio of the actual heat transfer rate(mc)p (Ti-- Tout), Tout=Tc(O), to the maximum hypothetical rateunder the same conditions (mc)min (Ti- νi), is shown in Figs. 6, 7respectively versus the number of transfer units and the flow capacitance ratio. As known, the balanced heat exchangers E = 1) present the worst behaviour ; the effectiveness does not depend on R and is the same for reciprocal values of the flow capacitance ratio.U形管换热器m . Spiga和g . Spiga,博洛尼亚摘要:分析解决方案提供一些两相流体在u形管换热器中的分布情况。
计算机专业毕业设计论文外文文献中英文翻译——java对象
1 . Introduction To Objects1.1The progress of abstractionAll programming languages provide abstractions. It can be argued that the complexity of the problems you’re able to solve is directly related to the kind and quality of abstraction。
By “kind” I mean，“What is it that you are abstracting?” Assembly language is a small abstraction of the underlying machine. Many so—called “imperative” languages that followed （such as FORTRAN，BASIC, and C) were abstractions of assembly language。
These languages are big improvements over assembly language，but their primary abstraction still requires you to think in terms of the structure of the computer rather than the structure of the problem you are trying to solve。
The programmer must establish the association between the machine model (in the “solution space，” which is the place where you’re modeling that problem, such as a computer) and the model of the problem that is actually being solved (in the “problem space,” which is the place where the problem exists). The effort required to perform this mapping, and the fact that it is extrinsic to the programming language，produces programs that are difficult to write and expensive to maintain，and as a side effect created the entire “programming methods” industry.The alter native to modeling the machine is to model the problem you’re trying to solve。
外文翻译--燃气报警器
外文翻译--燃气报警器福州大学至诚学院本科生毕业设计（论文）外文翻译题目：基于单片机可燃气体检测报警器的设计姓名：蔡佳阳学号： 211014128系别：信息工程系专业：电子信息工程年级： 2010级指导教师：（签名）年月日附录：外文文献及译文外文原文1 ：Combustible gas alarmCombustible gas alarmto prevent gas leakage as a powerful weapon, it has, however, does not seem to have attracted the attention it deserves. This security and household fire extinguishers can be placed on a par, or even more than the fire extinguisher into the family of the little things that most families do not see it as one thing, do not even know there can be such a fundamental solution to gas poisoning and gas explosion, "the protection of God" exists. Shanghai as an example, last year, due to poisoning and cooking gas water heater overflow out, piece of rubber hose off the aging caused by gas leakage and poisoning caused by a total of 86 deaths, accounting for all the gas data of accidents were 84%. However, according to an authoritative department to another survey released shows that in Shanghai, about three million gas users, the installation of domesticgas leakage alarm of less than 10%.In their daily lives, whether it is gas poisoning or gas explosion, because of gas leak into the sky. Home life, no one is inseparable from the use of gas, no matter what you do more preventive measures, but a hundred secret inevitably very careful, not to mention of any fire safety measures are not taken on even more dangerous family. Therefore it is necessary to prepare a Combustible gas at home at any time for the owner guardian of the gas appliances, a gas alert to this invisible killer slipped quietly out to help the owner of the elimination offamily problems in the bud, the domestic security of the good housekeeper, so that family members with the use of gas, the use of hearts at ease. For example, there are many families of fire gas explosion, do not know in the room full of gas leaking out, the blind use of electricalswitches and tragedy in an instantif there is an alarm, a tragedy like this ,can be greatly avoided.Combustible gas alarm into the family, will become a good home security to help, this is an indisputable fact Product Description:Detection of gas: natural gas, liquefied petroleum gas, city gas (H2)Size: 115mm * 71mm * 43.3mm(1) add automatic sensor drift compensation, the real and omitted to prevent the false positives.(2) The failure prompted the police to enable the user to replace and repair, to prevent the non-reported.(3) MCU control the entire process, working temperature -40 degrees to 80 degrees. Operating voltage: 220V AC or 110V AC, 12VDC-20VDC Additional features: linkage exhaust fan, the manipulator, the solenoid valveNetworking: wired networking functions: (NO, NC) Wireless networking: 315MHZ/433MHZ (2262 OR 1527)译文：燃气报警器燃气报警器作为预防燃气泄漏的有力武器，它的出现却似乎并没有引起人们应有的注意。
毕业论文文献外文翻译----危机管理：预防,诊断和干预文献翻译-中英文文献对照翻译
第1页 共19页中文3572字毕业论文（设计）外文翻译标题：危机管理-预防，诊断和干预一、外文原文标题：标题：Crisis management: prevention, diagnosis and Crisis management: prevention, diagnosis andintervention 原文：原文：The Thepremise of this paper is that crises can be managed much more effectively if the company prepares for them. Therefore, the paper shall review some recent crises, theway they were dealt with, and what can be learned from them. Later, we shall deal with the anatomy of a crisis by looking at some symptoms, and lastly discuss the stages of a crisis andrecommend methods for prevention and intervention. Crisis acknowledgmentAlthough many business leaders will acknowledge thatcrises are a given for virtually every business firm, many of these firms do not take productive steps to address crisis situations. As one survey of Chief Executive officers of Fortune 500 companies discovered, 85 percent said that a crisisin business is inevitable, but only 50 percent of these had taken any productive action in preparing a crisis plan(Augustine, 1995). Companies generally go to great lengths to plan their financial growth and success. But when it comes to crisis management, they often fail to think and prepare for those eventualities that may lead to a company’s total failure.Safety violations, plants in need of repairs, union contracts, management succession, and choosing a brand name, etc. can become crises for which many companies fail to be prepared untilit is too late.The tendency, in general, is to look at the company as a perpetual entity that requires plans for growth. Ignoring the probabilities of disaster is not going to eliminate or delay their occurrences. Strategic planning without inclusion ofcrisis management is like sustaining life without guaranteeinglife. One reason so many companies fail to take steps to proactively plan for crisis events, is that they fail to acknowledge the possibility of a disaster occurring. Like an ostrich with its head in the sand, they simply choose to ignorethe situation, with the hope that by not talking about it, it will not come to pass. Hal Walker, a management consultant, points out “that decisions will be more rational and better received, and the crisis will be of shorter duration, forcompanies who prepare a proactive crisis plan” (Maynard, 1993) .It is said that “there are two kinds of crises: those that thatyou manage, and those that manage you” (Augustine, 1995). Proactive planning helps managers to control and resolve a crisis. Ignoring the possibility of a crisis, on the other hand,could lead to the crisis taking a life of its own. In 1979, theThree-Mile Island nuclear power plant experienced a crisis whenwarning signals indicated nuclear reactors were at risk of a meltdown. The system was equipped with a hundred or more different alarms and they all went off. But for those who shouldhave taken the necessary steps to resolve the situation, therewere no planned instructions as to what should be done first. Hence, the crisis was not acknowledged in the beginning and itbecame a chronic event.In June 1997, Nike faced a crisis for which they had no existi existing frame of reference. A new design on the company’s ng frame of reference. A new design on the company’s Summer Hoop line of basketball shoes - with the word air writtenin flaming letters - had sparked a protest by Muslims, who complained the logo resembled the Arabic word for Allah, or God.The council of American-Islamic Relations threatened aa globalNike boycott. Nike apologized, recalled 38,000 pairs of shoes,and discontinued the line (Brindley, 1997). To create the brand,Nike had spent a considerable amount of time and money, but hadnever put together a general framework or policy to deal with such controversies. To their dismay, and financial loss, Nike officials had no choice but to react to the crisis. This incident has definitely signaled to the company that spending a little more time would have prevented the crisis. Nonetheless,it has taught the company a lesson in strategic crisis management planning.In a business organization, symptoms or signals can alert the strategic planners or executives of an eminent crisis. Slipping market share, losing strategic synergy anddiminishing productivity per man hour, as well as trends, issues and developments in the socio-economic, political and competitive environments, can signal crises, the effects of which can be very detrimental. After all, business failures and bankruptcies are not intended. They do not usually happen overnight. They occur more because of the lack of attention to symptoms than any other factor.Stages of a crisisMost crises do not occur suddenly. The signals can usuallybe picked up and the symptoms checked as they emerge. A company determined to address these issues realizes that the real challenge is not just to recognize crises, but to recognize themin a timely fashion (Darling et al., 1996). A crisis can consistof four different and distinct stages (Fink, 1986). The phasesare: prodromal crisis stage, acute crisis stage, chronic crisisstage and crisis resolution stage.Modern organizations are often called “organic” due tothe fact that they are not immune from the elements of their surrounding environments. Very much like a living organism, organizations can be affected by environmental factors both positively and negatively. But today’s successfulorganizations are characterized by the ability to adapt by recognizing important environmental factors, analyzing them, evaluating the impacts and reacting to them. The art of strategic planning (as it relates to crisis management)involves all of the above activities. The right strategy, in general, provides for preventive measures, and treatment or resolution efforts both proactively and reactively. It wouldbe quite appropriate to examine the first three stages of acrisis before taking up the treatment, resolution or intervention stage.Prodromal crisis stageIn the field of medicine, a prodrome is a symptom of the onset of a disease. It gives a warning signal. In business organizations, the warning lights are always blinking. No matter how successful the organization, a number of issues andtrends may concern the business if proper and timely attentionis paid to them. For example, in 1995, Baring Bank, a UK financial institution which had been in existence since 1763,ample opportunitysuddenly and unexpectedly failed. There wasfor the bank to catch the signals that something bad was on thehorizon, but the company’s efforts to detect that were thwarted by an internal structure that allowed a single employee both to conduct and to oversee his own investment trades, and the breakdown of management oversight and internalcontrol systems (Mitroff et al., 1996). Likewise, looking in retrospect, McDonald’s fast food chain was given the prodromalsymptoms before the elderly lady sued them for the spilling ofa very hot cup of coffee on her lap - an event that resulted in a substantial financial loss and tarnished image of thecompany. Numerous consumers had complained about thetemperature of the coffee. The warning light was on, but the company did not pay attention. It would have been much simplerto pick up the signal, or to check the symptom, than facing the consequences.In another case, Jack in the Box, a fast food chain, had several customers suffer intestinal distress after eating at their restaurants. The prodromal symptom was there, but the company took evasive action. Their initial approach was to lookaround for someone to blame. The lack of attention, the evasiveness and the carelessness angered all the constituent groups, including their customers. The unfortunate deaths thatptoms,occurred as a result of the company’s ignoring thesymand the financial losses that followed, caused the company to realize that it would have been easier to manage the crisis directly in the prodromal stage rather than trying to shift theblame.Acute crisis stageA prodromal stage may be oblique and hard to detect. The examples given above, are obvious prodromal, but no action wasWebster’s New Collegiate Dictionary, an acute stage occursacutewhen a symptom “demands urgent attention.” Whether the acutesymptom emerges suddenly or is a transformation of a prodromalstage, an immediate action is required. Diverting funds and other resources to this emerging situation may cause disequilibrium and disturbance in the whole system. It is onlythose organizations that have already prepared a framework forthese crises that can sustain their normal operations. For example, the US public roads and bridges have for a long time reflected a prodromal stage of crisis awareness by showing cracks and occasionally a collapse. It is perhaps in light of the obsessive decision to balance the Federal budget that reacting to the problem has been delayed and ignored. This situation has entered an acute stage and at the time of this writing, it was reported that a bridge in Maryland had just collapsed.The reason why prodromes are so important to catch is thatit is much easier to manage a crisis in this stage. In the caseof most crises, it is much easier and more reliable to take careof the problem before it becomes acute, before it erupts and causes possible complications (Darling et al., 1996). In andamage. However, the losses are incurred. Intel, the largest producer of computer chips in the USA, had to pay an expensiveprice for initially refusing to recall computer chips that proved unreliable o n on certain calculations. The f irmfirm attempted to play the issue down and later learned its lesson. At an acutestage, when accusations were made that the Pentium Chips were not as fast as they claimed, Intel quickly admitted the problem,apologized for it, and set about fixing it (Mitroff et al., 1996). Chronic crisis stageDuring this stage, the symptoms are quite evident and always present. I t isIt is a period of “make or break.” Being the third stage, chronic problems may prompt the company’s management to once and for all do something about the situation. It may be the beginning of recovery for some firms, and a deathknell for others. For example, the Chrysler Corporation was only marginallysuccessful throughout the 1970s. It was not, however, until the company was nearly bankrupt that amanagement shake-out occurred. The drawback at the chronic stage is that, like in a human patient, the company may get used to “quick fixes” and “band “band--aid”approaches. After all, the ailment, the problem and the crisis have become an integral partoverwhelmed by prodromal and acute problems that no time or attention is paid to the chronic problems, or the managers perceive the situation to be tolerable, thus putting the crisison a back burner.Crisis resolutionCrises could be detected at various stages of their development. Since the existing symptoms may be related todifferent problems or crises, there is a great possibility thatthey may be misinterpreted. Therefore, the people in charge maybelieve they have resolved the problem. However, in practicethe symptom is often neglected. In such situations, the symptomwill offer another chance for resolution when it becomes acute,thereby demanding urgent care. Studies indicate that today anincreasing number of companies are issue-oriented and searchfor symptoms. Nevertheless, the lack of experience in resolvinga situation and/or inappropriate handling of a crisis can leadto a chronic stage. Of course, there is this last opportunityto resolve the crisis at the chronic stage. No attempt to resolve the crisis, or improper resolution, can lead to grim consequences that will ultimately plague the organization or even destroy it.It must be noted that an unsolved crisis may not destroy the company. But, its weakening effects can ripple through the organization and create a host of other complications.Preventive effortsThe heart of the resolution of a crisis is in the preventiveefforts the company has initiated. This step, similar to a humanbody, is actually the least expensive, but quite often the mostoverlooked. Preventive measures deal with sensing potential problems (Gonzales-Herrero and Pratt, 1995). Major internalfunctions of a company such as finance, production, procurement, operations, marketing and human resources are sensitive to thesocio-economic, political-legal, competitive, technological, demographic, global and ethical factors of the external environment. What is imminently more sensible and much more manageable, is to identify the processes necessary forassessing and dealing with future crises as they arise (Jacksonand Schantz, 1993). At the core of this process are appropriate information systems, planning procedures, anddecision-making techniques. A soundly-based information system will scan the environment, gather appropriate data, interpret this data into opportunities and challenges, and provide a concretefoundation for strategies that could function as much to avoid crises as to intervene and resolve them.Preventive efforts, as stated before, require preparations before any crisis symptoms set in. Generally strategic forecasting, contingency planning, issues analysis, and scenario analysis help to provide a framework that could be used in avoiding and encountering crises.出处：出处：Toby TobyJ. Kash and John R. Darling . Crisis management: prevention, diagnosis 179-186二、翻译文章标题：危机管理：预防，诊断和干预译文：本文的前提是，如果该公司做好准备得话，危机可以更有效地进行管理。
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金融体制、融资约束与投资——来自OECD的实证分析R．SemenovDepartment of Economics，University of Nijmegen，Nijmegen（荷兰内梅亨大学，经济学院）这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时，我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致，并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。
一、引言各个国家的企业在显著不同的金融体制下运行。
金融发展水平的差别(例如，相对GDP的信用额度和相对GDP的相应股票市场的资本化程度），在所有者和管理者关系、企业和债权人的模式中，企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。
然而，经济理论表明市场摩擦，诸如信息不对称和激励问题会使获得外部资本更加昂贵，并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素，例如内部产生资金数量、新债务和权益的可得性，共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料（可参考，例如Fazzari（1998）、 Hoshi(1991)、 Chapman（1996）、Samuel(1998））.大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。
这项研究结果解释表明企业投资受限于外部资金的可得性。
很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本，减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置（参看Levine（1997)的评论文章）。
因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。
所以，在金融体制发展水平一定时，与金融中介机构关系密切的企业和没有关系的企业相比，具有更低的资本成本和更高的资金可得性。
很多研究表明企业—债权人关系确实有助于提高企业获取外部资金的可能性.我们可以期望银企之间明显的紧密关系占主导地位的国家的融资约束比银企之间公平关系占主导地位的国家的低。
很多有关投资-现金流敏感性的国家之间对比表明金融体制的这些特征的影响确实很重要。
因而，这些文献发现投资在美国比在法国对现金流更具敏感性（Mulkay,2000），在英国比在德国对现金流更具敏感性（Bond，1999）,在英国比在比利时、法国、德国对现金流更具敏感性（Bond，2003)。
这些学者的以前的两篇论文认为这些差别可能是由金融体制上的差异造成的。
当然，两个或四个国家，在金融体制的很多方面会有所差异，也可能在影响企业投资决策的其他因素上会有所差别。
很难从上述提到的论文中得出有关金融体制的强有力的推论。
这种推论要求通过搜集更多国家样本，对金融体制的指标和融资约束指标在投资时关系直接进行数理经济学分析.两份研究做了这种调查。
Demirguc-Kunt和Maksimovic（1998），运用26个国家大量的企业样本，计算了每个国家比当它们只使用内部产生的资金发展更快时企业所占的比例。
结果表明，这种比例和金融发展水平正相关。
正如Love(2003)指出的，这种分析几乎没有设计到资金的效率：高速发展的企业是否与最佳的投资机会相符还不明朗。
Love(2003），对来自40个国家的样本企业的研究结果表明，具有更发达的金融体制的国家的企业受到的融资约束更少.然而，他的分析带有偏好的技术问题。
两次研究都没有探讨出投资者-企业关系的特点对投资决策的影响。
此篇论文旨在研究金融体制的差异（同时研究金融发展水平和投资者-企业关系的特点）对企业面临的融资约束的影响。
我们构建一组数据，它包含11个发达国家的制造企业，用这组数据估计不同国家的企业的投资水平对内部资金可得性敏感程度。
然后，我们考查这些敏感程度的差异是否和这些个国家的金融体制的差异有关联.本论文的其余部分组织结构如下：在第二部分，理论探讨表明金融体制对企业外部融资可获得性影响的趋向，相关的实证文献将会在第三部分讨论。
第四讨论方法论和数据，第五部分陈述分析结果.第六讨论这些结果，第七部分总结。
二、理论根据古典理论的观点，就像莫迪利尼（Modigliani）和米勒(Mill）的著名分析已经得出的观点一样，一个企业的投资决策与其资本结构选择无关。
完美的资本市场使得外部资金是内部资金的完美替代。
因而,企业对于不同融资方式的选择是漠视的.然而,大量的理论研究结果表明,完美资本市场的消费是难以达到.资本市场的不完美的最重要的表现是信息不对称问题。
Myres和Majluf（1984)研究表明，如果管理者比投资者更了解企业的前景，那么该企业的风险担保（或风险资产）有时会被低估，进而提高外部融资的成本。
Jensen和Meckling（1976）认为所有者的利益会在以下几个重要方面偏离债权人的意志：所有者偏好风险高的投资项目、有发行优先于当前债务人的债务的激励（这便提高了当前债权人员的风险)，当面临破产的风险时，有激励将企业的资产转移并且在破产时没有激励努力改善回报率。
这些激励问题提高了信贷成本。
这篇文献表明，由于信息和激励等问题，外部融资成本要比内部资金要高.从而，企业面临融资约束，这也意味着融资因素，诸如内部资金的数量、新债和权益的可得性，将会影响企业的投资者决策.越发达的金融体制可能会提高资金的可得性并减少企业的融资成本（可参看Levine（1997）的评论文章）.金融中介机构和证券市场为贸易、联营和分散风险提供了重要工具，进而缓解了与个人企业、行业、地区、国家等的风险，引导证券投资组合流向预期回报率更高的投资项目.金融中介机构在攫取和处理投资信息时节约成本.这有助于信息的攫取和处理,使最有前景的投资项目获取更好的选择，从而改善资源配置.金融中介机构同时允许联营,进而可以节约控制成本。
股市促使企业信息的攫取和推广。
通过给予股票行市所有者管理补助，这样便可以使管理者和他们的利益一致。
发达的股票市场有助于市场对企业控制的运行，这进一步使管理者的利益和股票所有者的利益达成一致.所有的这一切都会更大地激励个人投资在更高收益和更长期的投资项目,这有助于私人储蓄流向这类项目的投资上。
因而，我们预期拥有更加发达的金融体制的国家将会比那些金融体制不发达的国家承受更少的融资约束.紧密的银企关系有可能提高企业资金的可得性并减少企业的资本成本.“通过紧密而持久的互动合作，一家企业可以提供给贷款者足够的信息和声音，这样企业就可以降低成本并提高信贷的可得性”(Petersen和Rajan（1994）)。
信息的数量和声音的力度甚至更大，如果贷款者（债权人）在企业内拥有自己的股份，就像例证中国家的德国和日本.紧密的关系可能有助于处在融资困境中的资本的获取，但是一种切实可行的办法。
当一家企业的财务状况得到好转的话会及时归还银行贷款，那么银行可能会为这种企业贷款。
但是这样一家企业会有违约的激励，从而在没有另外安排的情况下不能兑现自己的承诺.长期紧密的银企关系可以有助于解决这些问题(Mayre,1988）.在紧密的银企关系下，双方均能够对彼此有一个更全面的了解，这可以减少控制成本（Lehmann和Neuberger，2001）。
契约可以以更低的成本予以重新谈判(Sako，1992，Elsas和Krahnen，1998）。
如果一家银行既是一家企业债权人又是该家企业的股东，那么这家企业将减少以牺牲一位投资者的利益来增加另外一位投资者的利益的激励（Aoki，1994），并且当一家企业处于拖欠债务的边缘时投资者之间出现冲突将会减少(Hoshi，1991）.在资金紧张期间，相对于与银行具有公平联系的企业，一家银行将更少可能对与其具有紧密联系的企业迅速提高利率（Congigliani,1997）。
最后,一家银行与一家企业之间的关联标志着这家企业对其余投资者的商誉（Audretsch和Elston，1999）。
总之，这个理论预料紧密的银行关系有可能提高企业资金的可得性并减少企业的资本成本。
因此，我们应该预期在银企关系紧密占主导地位的国家比银企处于公平关系占主导地位的国家所受的融资约束将更少。
三、相关实证文献我们的论文是有关最近几个实证文献。
两篇论文分析是否企业与银行紧密关系面临弱金融拮据的投资。
星等。
（1991）发现这是日本企业的情况下,和Audretsch和埃尔斯顿（1999)的德国公司。
Becht和拉米雷斯（2003)表明,在预世第一次世界大战期间，在采矿和钢铁德国公司那些没有参加与的行业之一大型全能银行进行融资约束, 虽然这不是为公司隶属于情况银行。
休斯顿和詹姆斯（2001）发现，除250大美国企业，那些有关系单一银行较少融资约束，提供该投资并不太大（小于100％资本存量）,但公司需要更大的投资更受限时,他们有一个单一的银行。
要注意，虽然，这是很重要的关系与单一银行不一定是“密切"。
其他几个文献建立的密切银企关系，提高可用性并降低债务融资对公司的成本。
彼得森和拉詹（1994）认为，商业信用是最昂贵的外部资金来源，以便利用贸易公司信贷更可能是债务约束。
对于约3400美国企业用较少的样本现有员工500多人，他们发现贸易的程度信用使用率是负向的持续时间有关的现有的借贷关系。
彼得森和拉詹发现，银行收取的利率不相关的借贷关系的持续时间.这结果是由Blackwell和温特斯(1997）证实谁使用的银行贷款记录来中小企业企业;但作者显示，该权益率较低时，从贷款承诺银行代表企业的总的较大部分债务。
Berger和Udell（1995），使用相同的数据集作为彼得森和拉詹（1994）发现，公司与较长的借贷关系有抵押担保频率较低，必须在支付较低的利息率贷款承诺。
温斯坦和Yafeh（1998）发现小日本企业有密切的银行关系是资本密集型，显示弱金融拮据的投资.德国中小企业，哈霍夫及Korting（1998年)和莱曼和纽伯格(2001）发现，私人银行提供信贷更容易以较低的利率，Elsas 和Krahnen（1998）发现，“房屋银行”在突发状况提供流动性保险借款人评级恶化（虽然他们没有找到证据表明，“房子银行收费较低的利率）.对于日本来说，Hoshi et al.（1990）,发现企业有紧密联系的“主银行”是更能够当他们在金融投资心疼.对于意大利,最近的工作表明，信贷与排他性和持续时间增加的访问坚定和银行之间的关系(参见Foglia的资料，1998）。