附录二：外文翻译
附录二：
循环流化床三维模拟横向气流喷雾蒸发
TongH．Lee l．Xiaohua Wang2,Chao Zhu l
1。机械工程系,新泽西技术学院，纽瓦克．NJ 07102，美国
2。核能工程部门,阿贡国家实验室、阿贡IL60439,美国
摘要：
循环流化床进行三维数值模拟横向液氮喷雾注入矩形截面,喷雾从大的纵横比和扇形角的矩形喷嘴喷出。横向气流模拟使用集流体方法，而液氮喷雾使用拉格朗日描述轨迹的方法。这项研究中被认为是双向耦合的欧拉-拉格朗日相互作用。我们的仿真模拟表明，喷雾普及率明显受到固体载荷的影响。由于强烈的错流对流,温度轮廓的气体和固体阶段,以及蒸汽区域,被发现偏离喷雾区域。喷雾蒸发会使一个固体区域的蒸汽浓度非常低，虽然有一层致密的固体周围的蒸汽。喷雾往往覆盖后喷雾渗透区域原始射出角度和风扇角度。不同于气相渗透，喷雾截面形状沿喷雾变化。
关键词：数值模拟，雾化，蒸发，气固流化床
简介：
气固循环流化床中，油精炼过程中蒸发液体喷洒，流化催化裂化（FCC）合成，聚乙烯冷凝模式操作，湿式洗涤系统的悬浮颗粒物的污染控制，以及在煤的气化过程中的相互作用的三个阶段相旺是非常复杂的，特别是液滴的蒸发，液滴碰撞为主的固体，雾化液体的快速蒸发对气固混合效果显著。典型的影响包括当地的相变温度降低，固体的浓度稀释，和相位变化的速度，湍流强度和相冲突。另一方面。液滴的蒸发速率不仅取决于液滴和混合流之间的热转移，还有对液滴组成的扩散速率从界面到蒸汽的气体混合物（施瓦策和布朗克，2000）。
（常某等人，1998；高某等人，2001）通过提升管反应器油喷等一些数值模拟，试图揭示三相流的详细信息。在这些模拟中，颗粒的液滴碰撞和一些重要的相位之间的相互作用被忽略了。（A1。王某等人。2004）一个简单的固碰撞和相相互作用的相关性传热模型进行了二维模拟在稀CFB流同心喷雾。
文中，我们模拟一个三维的液氮喷雾空气催化裂化循环流化床系统。喷雾横流模式从一个具有大的纵横比和扇形角的矩形喷嘴。本研究的目的是为了更好的了解，否则很难通过实验研究的流动结构和相位的相互作用。
数值方法：
（王某等人。，2004）用数值模拟的方法详细讨论，在我们之前的研究发现。一组关键的控制方程如下。
输气固体流动方程
它是假定颗粒单分散无磨损、气相是空气和氮蒸气在空气和氮气气相具有相同的物理性质的混合物，所以没有气态物种方程需要解决的问题。因此，气相流动的控制方程如下
源条件不仅从质量，还从天然气和液滴之间的动量和能量传递着手，同样的方程给出了固相的
在附加源项由于液滴碰撞作用的固体
湍流模型：
在一个动荡的颗粒的多相流中，颗粒分散在湍流流动的波动。颗粒的加入可以提高或降低湍流输运行为，影响颗粒和液滴蒸发阶段的流动，湍流输运机理更加复杂。到目前为止没有文献与蒸发解释三相湍流调制或两相震荡。基于喷嘴直径和喷射速度，喷雾射流具有典型的30000的雷诺兹数，即湍流效应应占本相混合的过程。在这项研究中，一个简单的普朗特混合长度模型（PMLM）被用来为有效的流体粘度的特征长度尺度改变特性。
液滴蒸发和弹道方程
测量液滴的速度和弹道根据Lagmngian弹道方法计算，
液滴的蒸发率的计算方法是（Aggarwal等人，1984）
固体液滴相互作用
蒸发的液滴和颗粒之间的碰撞是一种非常复杂的现象。没有可靠的传热传质模型是有效的。特别是对于本模型中的假设，一个较大的温度差，颗粒在相互碰撞的液滴碰撞时，热量从固体颗粒的碰撞液滴转移到通过蒸气薄膜层周围的粒子
结果与讨论：
问题描述和计算域
在这项研究中，我们模拟了一个交叉流动液氮喷雾注入的充分发展流动的空气流化催化裂化循环流化床具有矩形横截面。一个矩形喷管1x6毫米与10°。扇角是用来提供一个流体的160μ米与35米/秒，所有的注入速度和液滴平均直径，喷氮积累率目前是1.2g/sec。在循环流化床空气催化裂化流程在300K和2m／s，计算域选择为30cm×10cm×2.5cm 与20×20×30网格分布，如图所示L.为了研究固体负荷对喷雾蒸发的影响，两组数值模拟结果进行了比较，一个固体的体积分数为5%，其他没有任何固体
图 1 计算域几何
土壤负荷对蒸发长度和结构的影响
固含量对喷雾蒸发长度的影响如图2所示。这表明，喷雾结构是由固体负荷显着改变。蒸发的长度和体积分数为5%的固体颗粒是小于约25%，没有固体。结果表明，与固体相比喷雾蒸发得更快，例如，约60%的总蒸发发生在5%的情况下的固体喷射区域三分之一，同样的比例在没有固体蒸发的情况下，喷雾区域三分之二。图3显示了喷雾质量分布沿射流。
（a）喷雾无固相（B）5%固体喷
图2 固体负荷对喷雾结构的影响（液滴的大小为基础）
图3 蒸发率0%和5%的固体
气/固温度分布对蒸发的影响
气固两相流的液滴的蒸发，气体和固体由于吸收潜热，也将导致温度降低，从周围的气固两相介质，如图4所示。值得注意的是，最低温度分布偏离水滴轨迹而贴近另一面墙。这一结果是不同于我们以前的数值结果与同步喷射蒸发，在这种情况下，气体/固体的温度等值线表示喷雾蒸发区。这种偏差的主要原因是交叉对流。由于其惯性，液滴直走沿原方向但蒸发的蒸汽注射迅速卷入尾迹区的气固流动，对流最低温度分布情况没有出现在半固体的计算域，而5%例喷雾形成的轨迹，最低轮廓上面所示的喷嘴尖端附近。这表明越来越多的固体负荷有较大的对流热传递的方向。这也是有趣的，因为没有固体，存在一个大的低温区附近的喷雾的对面。这是由于在一个密闭室流到蒸发的蒸汽回流管流的热对流是微弱的。
图4 固体的温度分布对蒸发的影响（单位：K1）。
图 5 蒸发对固体体积分数的影响
蒸发作用对固体含量稀释和气体速度的影响
气固两相流的结果：在过量的蒸汽生产产生的固体，浓度稀释，雾化液体快速蒸发。图5说明了固体的稀释效应，从对流主喷射区偏离了。值得注意的是，蒸汽膨胀导致的压缩效果，产生凝聚周围的蒸汽区固体层。膨胀的蒸汽使得密闭室的固体浓度略有增加。
图6显示了液滴蒸发的气体速度分布的影响。结果表明，在蒸汽区域气流速度比周围的速度急剧增加（2米/秒）。气体的速度模式是类似的气体的温度轮
廓。在图2的喷雾区域相比，它再次指出，蒸汽区明显偏离喷雾区的强交叉对流
图6 固体加载对气流速度的影响(米/秒)
喷雾和蒸汽的横截面形状和尺寸
图7 喷雾横截面的形状和大小(上没有固体;下5%固体)
图8 喷嘴喷雾截面长宽比和距离
图7说明了喷雾典型截面的轮廓，这是基于液滴大小分布在喷雾截面。结果表明，矩形喷嘴横截面保持基本矩形的形状，但在不同的纵横比和尺寸沿喷雾渗透路径。图8显示了高宽比和喷射截面从喷嘴的距离的函数的大小的变化。可以看出，喷射宽度变化遵循原喷嘴扇形角，而喷射高度变化不大。
水蒸气的截面轮廓从气体的速度分布如图9所示的定义：结果表明，由于流动对流和蒸发，水蒸气的横截面形状不再是矩形。
图9 蒸汽横截面的形状和大小(上没有固体;下5%固体)
总结：
三维数值模拟已经进行的交叉流动液氮喷入空气循环流化床提升管催化裂化的矩形。固体加载对喷雾蒸发长度和喷雾结构具有显著影响。由于强烈的交叉对流，气体和固体阶段的温度轮廓明显偏离了喷枪轨迹。与周围的固体负荷为5%（体积比）。蒸发的长度大约是25%比60%不缩短固体蒸发已经发生在一个三分之二的喷雾贯穿总长度。喷雾蒸发。在气相区的固体浓度从5%稀释到2 %的致密层的周边区域的固体再。温度高达50 K耗竭是固体阶段得到的。矩形喷嘴横截面保持基本矩形的形状，叶片长宽比和大小以及喷雾的贯穿距离路径。然而，由于流动对流和蒸发，蒸气的截面形状不再是矩形。
符号：
C
阻力系数 y 质量分数
d
比热
C
p
D 扩散系数希腊符号
g 重力ε体积分数
H 热传输速率Γ体积蒸发速率
I 动量交换ρ密度
m 质量
液滴的蒸发速率下标
p 压力∞环境
q 热流量 d 滴
r 半径 g 气体
S 应力 m 除了蒸气的混合物
T 温度 p 质点
t 时间 s 固体量
v 速度 v 蒸汽
W 分子量 x 位置坐标
参考书：
S K Aggarwal．A Y.Tong,W.A .Strignano，“A Comparison of Vaporization Modelsin Spray
Calculations”，AIAA Journal，22，1448—457(1984)
S L Chang，S．A．Lottes,B. Golched, M．Petrick，“Interaction of Multi—phase Hydrodynamics，
Droplet Evaporation, and Chemical Kineties in FCC Riser Reactions”，AIAA／ASMEJoint
Thermophysics and Heat Transfer Conf，l,26l一269(1998)
J. Gan，C .Xu，S .Lin，G. Yang，Y. Guo，“Simulations of Gas-Liquid-Solid 3-Phase Flow and
Reaction in FCC Riser Reactors”．AIChE J., 47,677-692(2001)
J .P.Sehwartze．S. Brocker,‘The evaporation of Water Into Air of Difierent Humidifies and
the Inversion Temperature Phenomenon”，Int. J .Heat&MassTran，43，
1791-1800(2000)．
X．Wang，C Zhu．R．Ahluwalia，“Numerical Simulation of Evaporating Spray Jets in Concurrent Gas-Solids Pipe Flows"’．Powder Technology, 140, 56-67(2004).
3-D SIMULATION OF CROSSFLOW EV APORATING SPRAYS IN CIRCULATNG FLUIDIZED BEDS
TongH．Lee l．Xiaohua Wang2,Chao Zhu l
1 .Department of Mechanical Engineering，New JerseyInstitute of Technology，Newark．NJ 07102，USA
2 .Nuclear Engineering Division，Argonne National Laboratory,Argonne，IL60439，USA Abstract
A 3-D numerical simulation is performed for a cross-low liquid nitrogen spray injected into all alr-FCC circulating fluldized bed of rectangular cross-section，The spray nozale is rectangular with a large aspect ratio and a fan angle. The alr-FCC flow is simulated using the melti-fluid method while the liquid nitrogen sprays are described using Lagrangian trajectory method. A two-way coupling of the Eulerian-Lagrangian interaction is considered in this study. Our simulation shows that the spray penetration is Significantly affected by the solids loadings. Due to the strong cross-flow convection, the temperature contours of gas and solids phases, as well as the vapor region, Are found to deviate away from the spray region. The simulation also hows that the spray evaporation leads to a very low solids concentration within the vapor region while there is a dense layer of solids surrounding the vapor region. The sprays tend to cover the spray penetration area following The original injecdon angle and fan angle. The change of spray cross-section shape along the spray penetration is very different from that of vapor phase.
Key Words：numerical simulation，spray，evaporation，gas-solids fluidized bed
Introduction
Evaporating liquid sprays in gas—solids circulating fluidized beds are found in fluidized catalytic cracking(FCC) process for oiI refining, in condensed mode operation of polyethylene synthesis．In wet scrubbing systems for pollution control of the suspended particulate，as well as in the coal gasification process The phase interactions mong the three phases are very complicated，especially with the droplet evaporation that is dominated by droplet-solids collisions. The rapid evaporation of liquid spray has significant effects on the gas-solid mixing．Typical effects include the reduction of local phase temperature，dilution of the solid concentration，and changes in phase velocity, turbulent intensity and phase collisions．On the other hand．The droplet
evaporation rate depends not only on the heat transfer between the droplet and the mixture streams，but so on the droplet component diffusion rate from the interface to the gas-vapor mixture (Schwartze and Brocker,2000)．
Some numerical simulations of oil spray in FCC risers were attempted to reveal detailed field information of three phase flows(Chang et at., 1998；Gao et af．，2001)．In these simulations，particle-droplet collisions and some important phase interactions were ignored．With a simple heat transfor model of droplet-solid collision and phase interaction correlations．（Wang et a1.2004)performed a 2-D simulation of a concentric spray in a dilute CFB flow．
In this paper We numerically simulate a three-dimensional liquid nitrogen spray in an air-Fcc CFB system．The spray is injected in a cross-flow mode from a rectangular nozzle with a large aspect ratio and a fan angle．This study is aimed to better understand the flow structure and phase interactions that are otherwise difficult to study experimentally．
Numerical Method
A detailed discussion on numerical simulation method can be found in our pervious paper(Wang et a1., 2004)．A set of key governing equations are summarized below．
Goveming Equations of Gas-Solid Flow
It is assumed that the solids are mono dispersed without attrition、The gas phase is a mixture of air and nitrogen vapor where the air and nitrogen vapor have the same physical properties so that no gaseous species equations need to be solved. Hence, the governing equations of gas phase flow are given by
where the source terms include contributions not only from the mass generation but also from the momentum and energy transfer between gas and droplets Similarly the equations for solid phase are given by
where the additional source terms account for effects due to droplets-solids collisions
Turbulence Model
In a turbulent particulate multi-phase flow，the particles are dispersed through turbulent flow fluctuations．The addition of particles can enhance or reduce the flow turbulence, affecting
transport behavior of both particle and flow phases with evaporating droplets，the turbulence transport mechanism becomes more complicated. So far no literature is available to explain the three-phase turbulence modulation or two-phase turbulenee with evaporations．Based on the nozzle diameter and jet velocity,the spray jet flow has a typical Reynolds number of 30,000，which means the turbulent effect should be accounted for in this phase-mixing process．In this study,a simple Prandtl mixing-length model(PMLM)was used, in which the effective fluid viscosity was modified by the characteristic turbulence length scale．
Equations of Droplet Traiectory and Evaporation
Velocities and trajectories of droplets are calculated based on Lagmngian trajectory approach which are given by，
Droplet evaporation rate is calculated by(Aggarwal et al，1984)
Solids-Droplets Interactions
Collision among evaprating droplets and particles is a very complicated phenomenon．No reliable heat and mass transfer model is available．Especially for cases with large temperature difference It is assumed in the present model that particles pene"ate or trapped in the colliding droplets upon collision and heat is transferred from a solid particle to t11e colliding droplet through a vapor Film Layer around the particle
Results and Discussion
Problem Statement and Computational Domain
In this study, we have simulated a cross flow liquid nitrogen spray injected into a fully developed air-FCC flow in a circulating fluidized bed with a rectangular cross-section. A rectangular nozzle of 1x6 mm with a 10°fan angle is used to provide a 1iquid nitrogen spray of mean droplet diameter of 160 μm with all injection velocity of 35 m/s and amass now rate of 1.2g/sec. The air-FCC flow in CFB is at 300K and 2m/s. The computational domain is selected to be 30cm x l0cm x 2.5cm with a grid distribution of 20×20×30, as shown in Figure l.In order to investigate the effect of solids loading on spray evaporation，two sets of numerical simulations are compared，one with 5％volume fraction of solids and the other without any solids
Figure 1 Computational domain geometry
Effect of Soils Loading on Evaporation Length and Structure
Effect of solids loading on spray evaporation length is shown in Figure 2. which shows that the spray structure is significantly altered by the solids loading. The evaporation length wim 5％volume fraction of solids is about 25％shorter than that without solids. It shows that，with sofids, spray evaporates much faster,for example, about 60％of total evaporation occurs within one third of spray region for case of 5％solids while the same percentage evaporated over two third of spray region for case without solids．Figure 3 shows spray mass distribufion along the jet.
(a)spray without solid (b) spray with 5％solid
Figure 2 Effect of solids Loading on Spray structure (droplet size based)．
Figure 3 Evaporation rate with 0％and 5％solid
Effeets of Evaporation on Gas/Solids Temperature Distributions
Droplet evaporation in a gas-solid flow also leads to a temperature reduction of the gas and solids due to the absorption of latent heat from the surrounding gas-solid media, as shown in Figure 4. It is noted that lowest temperature distribution deviates the droplet trajectory while the droplet goes straight towards the other side wall.This result is different from our previous numerical results with concurrent jet evaporation In which case the temperature contour of gas/solids represents that of spray evaporation region. The majn reason of this deviation is the cross flow convection. Due to their inertia, droplets keep going straight very much along the original injection direction but the evaporated vapor quickly engulfed into the wake region formed by gas-solids convection over the spray trajectory The lowest temperature distribution for case without solids appears at the half of the calculation domain whereas for 5％case，the lowest contour is shown above near the nozzle tip. This shows that more solid loading has the larger convection heat transfer to the cross direction．It is also interesting to note that, for case without solids．there exists a large low temperature region near the opposite side of the spray．This is due to the large recirculation of evaporated vapor in a confined chamber flow when the thernlal convection of pipe flow is weak．
Figure 4 Effects of evaporation on solids temperature distribution(unit：K1).
Figure 5 Effect of evaporation on solids volume fraction
Effect of Evaporation on Solids Concentration Dilution and Gas Velocities
The rapid evaporation of liquid spray in a gas-solid flow results in an excessive vapor production that produces a dilution of solids concentration. Figure 5 illustrates the dilution effect of solids in a region that is deviated away by convection from the main spray. It is noted that vapor expansion leads to a compression effect producing a condense layer of solids surrounding the vapor region. The vapor expansion also slightly increases the solids concentration in the confined chamber．
Figure 6 shows the gas velocity distribution under the influence of droplet evaporation．It is shown that the gas velocity inside the vapor region has a sharp increase compared to the ambient velocity (2 m/s).The gas velocity pattern is similar to the temperature contour of gas. Compared with spray regions in Figure 2, it is once again noted that the vapor region is significantly deviated from the spray region by the strong cross-flow convection
Figure 6 Effect of solids loading on gas velocity(m/s) Cross-section Shape and Size of Spray And Vapor
Figure 7 Shape and size of spray cross-section (upper is no solids；lower is 5％solids）
Figure 8 Aspect ratio and size of spray cross-section versus distance from nozzle
Figure 7 illustrates the typical cross-section contours of spray，which are based on droplet size distributions across the spray cross-sections. It is shown that the cross-sections of a rectangular nozzle spray maintain a basic rectangular shape but at varied aspect ratios and sizes along the spray penetration path. Figure 8 shows the variation of aspect ratio and size of spray coss-section as a function of distance from nozzle．It can be seen that the change of spray width follows the orginal nozzle fan angle while the spray height has little changes．
The cross-section contours of vapor are defined from gas velocity distributions as shown in Figure 9. It shows that shape of vaplor cross-section is no longer rectangular due to the flow convection and vapor evaporation．
Figure 9 Shape and size of vapor cross-section (upper is no solids；lower is 5％solids)
Conclusion
Three dimensional numerical simulations have been performed for the cross-flow liquid nitrogen sprays into an air-FCC rectangular CFB riser. The solids loading has a significa impac on both spray evaporation length and spray structure．Due to the Strong cross-flow convection, the temperature contours of gas and solids phases are significantly deviated from the spray trajectory. With an ambient solids loading of 5％(by volume). the evaporation length is about 25％shorte than without solids and 60％of evaporation already occurs within one thirds of total spray penetration length. With spray evaporation．The solids concentration in the vapor region is diluted from 5％to l.2％while a dense layer of solids surrounding the vapot region. The temperature depletion up to 50 K is obtained in solids phase. The cross-sections of a rectangular nozzle spray maintain a basic rectangular shape but at vane aspect ratios and sizes along the spray penetration path. However the shapc of the vapor cross-section is no longer rectangular due to the flow convection and vapor evaporation
Notation
C d drag coefficient y Mass fraction
C p specific heat
D diffusivity Greek Symbols
g gravity εvolume fraction
H heat transfer rate Γvolumetric evaporation rate
I momentum trailsfer ρdensty
m mass
droplet evaporation rate Subscripts
p pressure ∞ambient
q heat flux d droplet
r radius g gas
S stress m mixture excluding vapor
T temverature p particle
t timc s solid
v velocity v vapor
W molecular weight x location coordinate
References
S K Aggarwal．A Y.Tong,W.A .Strignano，“A Comparison of Vaporization Modelsin Spray Calculations”，AIAA Journal，22，1448—457(1984)
S L Chang，S．A．Lottes,B. Golched, M．Petrick，“Interaction of Multi—phase Hydrodynamics，Droplet Evaporation, and Chemical Kineties in FCC Riser Reactions”，AIAA／ASMEJoint Thermophysics and Heat Transfer Conf，l,26l一269(1998)
J. Gan，C .Xu，S .Lin，G. Yang，Y. Guo，“Simulations of Gas-Liquid-Solid 3-Phase Flow and Reaction in FCC Riser Reactors”．AIChE J., 47,677-692(2001)
J .P.Sehwartze．S. Brocker,‘The evaporation of Water Into Air of Difierent Humidifies and
the Inversion Temperature Phenomenon”，Int. J .Heat&MassTran，43，1791-1800(2000)．
X．Wang，C Zhu．R．Ahluwalia，“Numerical Simulation of Evaporating Spray Jets in Concurrent Gas-Solids Pipe Flows"’．Powder Technology, 140, 56-67(2004).
外文翻译---基于模糊逻辑技术图像上边缘检测
译文二： 1基于模糊逻辑技术图像上边缘检测[2] 摘要：模糊技术是经营者为了模拟在数学水平的代偿行为过程的决策或主观评价而引入的。下面介绍经营商已经完成了的计算机视觉应用。本文提出了一种基于模糊逻辑推理战略为基础的新方法，它被建议使用在没有确定阈值的数字图像边缘检测上。这种方法首先将用3?3的浮点二进制矩阵将图像分割成几个区域。边缘像素被映射到一个属性值与彼此不同的范围。该方法的鲁棒性所得到的不同拍摄图像将与线性Sobel运算所得到的图像相比较。并且该方法给出了直线的线条平滑度、平直度和弧形线条的良好弧度这些永久的效果。同时角位可以更清晰并且可以更容易的定义。关键词：模糊逻辑，边缘检测，图像处理，电脑视觉，机械的部位，测量 1.引言 在过去的几十年里，对计算机视觉系统的兴趣，研究和发展已经增长了不少。如今，它们出现在各个生活领域，从停车场，街道和商场各角落的监测系统到主要食品生产的分类和质量控制系统。因此，引进自动化的视觉检测和测量系统是有必要的，特别是二维机械对象[1,8]。部分原因是由于那些每天产生的数字图像大幅度的增加(比如，从X光片到卫星影像)，并且对于这样图片的自动处理有增加的需求[9,10,11]。因此，现在的许多应用例如对医学图像进行计算机辅助诊断，将遥感图像分割和分类成土地类别(比如，对麦田，非法大麻种植园的鉴定，以及对作物生长的估计判断)，光学字符识别，闭环控制，基于目录检索的多媒体应用，电影产业上的图像处理，汽车车牌的详细记录的鉴定，以及许多工业检测任务(比如，纺织品，钢材，平板玻璃等的缺陷检测)。历史上的许多数据已经被生成图像，以帮助人们分析(相比较于数字表之类的，图像显然容易理解多了)[12]。所以这鼓励了数字分析技术在数据处理方面的使用。此外，由于人类善于理解图像，基于图像的分析法在算法发展上提供了一些帮助(比如，它鼓励几何分析)，并且也有助于非正式确认的结果。虽然计算机视觉可以被总结为一个自动(或半自动)分析图像的系统，一些变化也是可能的[9,13]。这些图像可以来自超出正常灰度和色彩的照片，例如红外光，X射线，以及新一代的高光谱 [1]Abdallah A. Alshennawy, A yman A. Aly. Edge Detection in Digital Images Using Fuzzy Logic Technique[]J. World Academy of Science, Engineering and Technology, 2009, 51:178-186.
外文翻译
Load and Ultimate Moment of Prestressed Concrete Action Under Overload-Cracking Load It has been shown that a variation in the external load acting on a prestressed beam results in a change in the location of the pressure line for beams in the elastic range.This is a fundamental principle of prestressed construction.In a normal prestressed beam,this shift in the location of the pressure line continues at a relatively uniform rate,as the external load is increased,to the point where cracks develop in the tension fiber.After the cracking load has been exceeded,the rate of movement in the pressure line decreases as additional load is applied,and a significant increase in the stress in the prestressing tendon and the resultant concrete force begins to take place.This change in the action of the internal moment continues until all movement of the pressure line ceases.The moment caused by loads that are applied thereafter is offset entirely by a corresponding and proportional change in the internal forces,just as in reinforced-concrete construction.This fact,that the load in the elastic range and the plastic range is carried by actions that are fundamentally different,is very significant and renders strength computations essential for all designs in order to ensure that adequate safety factors exist.This is true even though the stresses in the elastic range may conform to a recognized elastic design criterion. It should be noted that the load deflection curve is close to a straight line up to the cracking load and that the curve becomes progressively more curved as the load is increased above the cracking load.The curvature of the load-deflection curve for loads over the cracking load is due to the change in the basic internal resisting moment action that counteracts the applied loads,as described above,as well as to plastic strains that begin to take place in the steel and the concrete when stressed to high levels. In some structures it may be essential that the flexural members remain crack free even under significant overloads.This may be due to the structures’being exposed to exceptionally corrosive atmospheres during their useful life.In designing prestressed members to be used in special structures of this type,it may be necessary to compute the load that causes cracking of the tensile flange,in order to ensure that adequate safety against cracking is provided by the design.The computation of the moment that will cause cracking is also necessary to ensure compliance with some design criteria. Many tests have demonstrated that the load-deflection curves of prestressed beams are approximately linear up to and slightly in excess of the load that causes the first cracks in the tensile flange.(The linearity is a function of the rate at which the load is applied.)For this reason,normal elastic-design relationships can be used in computing the cracking load by simply determining the load that results in a net tensile stress in the tensile flange(prestress minus the effects of the applied loads)that is equal to the tensile strength of the concrete.It is customary to assume that the flexural tensile strength of the concrete is equal to the modulus of rupture of the
英文文献翻译
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
外文翻译 - 英文
The smart grid Smart grid is the grid intelligent (electric power), also known as the "grid" 2.0, it is based on the integration, high-speed bidirectional communication network, on the basis of through the use of advanced sensor and measuring technology, advanced equipme nt technology, the advanced control method, and the application of advanced technology of decision support system, realize the power grid reliability, security, economic, efficient, environmental friendly and use the security target, its main features include self-healing, incentives and include user, against attacks, provide meet user requirements of power quality in the 21st century, allow all sorts of different power generation in the form of access, start the electric power market and asset optimizatio n run efficiently. The U.S. department of energy (doe) "the Grid of 2030" : a fully automated power transmission network, able to monitor and control each user and power Grid nodes, guarantee from power plants to end users among all the nodes in the whole process of transmission and distribution of information and energy bi-directional flow. China iot alliance between colleges: smart grid is made up of many parts, can be divided into:intelligent substation, intelligent power distribution network, intelli gent watt-hourmeter,intelligent interactive terminals, intelligent scheduling, smart appliances, intelligent building electricity, smart city power grid, smart power generation system, the new type of energy storage system.Now a part of it to do a simple i ntroduction. European technology BBS: an integration of all users connected to the power grid all the behavior of the power transmission network, to provide sustained and effective economic and security of power. Chinese academy of sciences, institute of electrical: smart grid is including all kinds of power generation equipment, power transmission and distribution network, power equipment and storage equipment, on the basis of the physical power grid will be modern advanced sensor measurement technology, network technology, communication
外文翻译 (2)
外文翻译： 会计081班顾洁芳0804002244 Stock:Expected and unexpected return To begin, for concreteness, we consider the return on the stock of a company called Flyers. What will determine this stock’s return in, say, the coming year? The return on any stock traded in a financial market is composed of two parts. First, the normal, or expected, return from the stock is the part of the return that shareholders in the market predict or expect. This return depends on the information shareholders have that bears on the stock, and it is based on the market’s understanding today of the important factors that will influence the stock in the coming year. The second part of the return on the stock is the uncertain, or risky, part. This is the portion that comes from unexpected information revealed within the year. A list of all possible sources of such information would be endless, bet here are a few examples: News about Flyers research Government figures released on gross domestic product (GDP) The results from the latest arms control talks The news that Flyers’s sales figures are higher tan expected A sudden, unexpected drop in interest rates Based on this discussion, one way to express the return on Flyers stock in the coming year would be: Total return = expected return + unexpected return R = E (R) + U Where R stands for the actual total return in the year, E(R) stands for the expected part of the return, and U stands for the unexpected part of the return. What this says is that the actual return, R, differs from the expected return, E(R), because of surprises that occur during the year. In any given year, the unexpected return will be positive or negative, but, through time, the average value of U will be zero. This simply means that on average, the actual return equals the expected return. Risk: systematic and unsystematic The unanticipated part of the return, that portion resulting from surprises, is the true risk of any investment. After all, if we always receive exactly what we expect, then the investment is perfectly predictable and by definition, risk-free. In other words, the risk of owning an asset comes from surprises-unanticipated events. There are important differences, though, among various sources of risk. Look back at our previous list of news stories. Some of these stories are directed specifically at Flyers, and some are more general. Which of the news items are of specific importance to Flyers? Announcements about interest rates or GDP are clearly important for nearly all companies, whereas the news about Flyers’s president, its research, or its sales is of specific interest to Flyers. We will distinguish between these
毕业论文外文翻译-图像分割
图像分割 前一章的资料使我们所研究的图像处理方法开始发生了转变。从输人输出均为图像的处理方法转变为输人为图像而输出为从这些图像中提取出来的属性的处理方法〔这方面在1.1节中定义过)。图像分割是这一方向的另一主要步骤。 分割将图像细分为构成它的子区域或对象。分割的程度取决于要解决的问题。就是说当感兴趣的对象已经被分离出来时就停止分割。例如，在电子元件的自动检测方面，我们关注的是分析产品的图像，检测是否存在特定的异常状态，比如，缺失的元件或断裂的连接线路。超过识别这此元件所需的分割是没有意义的。 异常图像的分割是图像处理中最困难的任务之一。精确的分割决定着计算分析过程的成败。因此，应该特别的关注分割的稳定性。在某些情况下，比如工业检测应用，至少有可能对环境进行适度控制的检测。有经验的图像处理系统设计师总是将相当大的注意力放在这类可能性上。在其他应用方面，比如自动目标采集，系统设计者无法对环境进行控制。所以，通常的方法是将注意力集中于传感器类型的选择上，这样可以增强获取所关注对象的能力，从而减少图像无关细节的影响。一个很好的例子就是，军方利用红外线图像发现有很强热信号的目标，比如移动中的装备和部队。 图像分割算法一般是基于亮度值的不连续性和相似性两个基本特性之一。第一类性质的应用途径是基于亮度的不连续变化分割图像，比如图像的边缘。第二类的主要应用途径是依据事先制定的准则将图像分割为相似的区域，门限处理、区域生长、区域分离和聚合都是这类方法的实例。 本章中，我们将对刚刚提到的两类特性各讨论一些方法。我们先从适合于检测灰度级的不连续性的方法展开，如点、线和边缘。特别是边缘检测近年来已经成为分割算法的主题。除了边缘检测本身，我们还会讨论一些连接边缘线段和把边缘“组装”为边界的方法。关于边缘检测的讨论将在介绍了各种门限处理技术之后进行。门限处理也是一种人们普遍关注的用于分割处理的基础性方法，特别是在速度因素占重要地位的应用中。关于门限处理的讨论将在几种面向区域的分割方法展开的讨论之后进行。之后，我们将讨论一种称为分水岭分割法的形态学
外文翻译
Journal of Industrial Textiles https://www.360docs.net/doc/c3214489.html,/ Optimization of Parameters for the Production of Needlepunched Nonwoven Geotextiles Amit Rawal, Subhash Anand and Tahir Shah 2008 37: 341Journal of Industrial Textiles DOI: 10.1177/1528083707081594 The online version of this article can be found at: https://www.360docs.net/doc/c3214489.html,/content/37/4/341 Published by: https://www.360docs.net/doc/c3214489.html, can be found at:Journal of Industrial TextilesAdditional services and information for https://www.360docs.net/doc/c3214489.html,/cgi/alertsEmail Alerts: https://www.360docs.net/doc/c3214489.html,/subscriptionsSubscriptions: https://www.360docs.net/doc/c3214489.html,/journalsReprints.navReprints: https://www.360docs.net/doc/c3214489.html,/journalsPermissions.navPermissions: https://www.360docs.net/doc/c3214489.html,/content/37/4/341.refs.htmlCitations: - Mar 28, 2008Version of Record >>
计算机网络-外文文献-外文翻译-英文文献-新技术的计算机网络
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
外文翻译computerprogram英文.doc
Computer Program 1 Introduction Computer Program, set of instructions that directs a computer to perform someprocessing function or combination of functions. For the instructions to be carried out, a computer must execute a program, that is, the computer reads the program, and then follow the steps encoded in the program in a precise order until completion. A program can be executed many different times, with each execution yielding a potentially different result depending upon the options and data that the user gives the computer. Programs fall into two major classes: application programs and operating systems. An application program is one that carries out somefunction directly for a user, such as word processing or game-playing. An operating system is a program that manages the computer and the various resources and devices connected to it, such as RAM,hard drives, monitors, keyboards, printers, and modems,so that they maybe used by other programs. Examples of operating systems are DOS, Windows 95, OS\2, and UNIX. 2 Program Development Software designers create new programs by using special applications programs, often called utility programs or development programs. A programmer uses another type of program called a text editor to write the new program in a special notation called a programming language. With the text editor, the programmer creates a text file, which is an ordered list of instructions, also called the program source file. The individual instructions that make up the program source file are called source code. At this point, a special applications program translates the source code into machine language, or object code— a format that the operating system
图像处理外文翻译 (2)
附录一英文原文 Illustrator software and Photoshop software difference Photoshop and Illustrator is by Adobe product of our company, but as everyone more familiar Photoshop software, set scanning images, editing modification, image production, advertising creative, image input and output in one of the image processing software, favored by the vast number of graphic design personnel and computer art lovers alike. Photoshop expertise in image processing, and not graphics creation. Its application field, also very extensive, images, graphics, text, video, publishing various aspects have involved. Look from the function, Photoshop can be divided into image editing, image synthesis, school tonal color and special effects production parts. Image editing is image processing based on the image, can do all kinds of transform such as amplifier, reducing, rotation, lean, mirror, clairvoyant, etc. Also can copy, remove stain, repair damaged image, to modify etc. This in wedding photography, portrait processing production is very useful, and remove the part of the portrait, not satisfied with beautification processing, get let a person very satisfactory results. Image synthesis is will a few image through layer operation, tools application of intact, transmit definite synthesis of meaning images, which is a sure way of fine arts design. Photoshop provide drawing tools let foreign image and creative good fusion, the synthesis of possible make the image is perfect. School colour in photoshop with power is one of the functions of deep, the image can be quickly on the color rendition, color slants adjustment and correction, also can be in different colors to switch to meet in different areas such as web image design, printing and multimedia application. Special effects production in photoshop mainly by filter, passage of comprehensive application tools and finish. Including image effects of creative and special effects words such as paintings, making relief, gypsum paintings, drawings, etc commonly used traditional arts skills can be completed by photoshop effects. And all sorts of effects of production are
外文翻译---图像的边缘检测
附：英文资料翻译 图像的边缘检测 To image edge examination algorithm research academic report Abstract Digital image processing took a relative quite young discipline, is following the computer technology rapid development, day by day obtains the widespread application.The edge took the image one kind of basic characteristic, in the pattern recognition, the image division, the image intensification as well as the image compression and so on in the domain has a more widespread application.Image edge detection method many and varied, in which based on brightness algorithm, is studies the time to be most long, the theory develops the maturest method, it mainly is through some difference operator, calculates its gradient based on image brightness the change, thus examines the edge, mainly has Robert, Laplacian, Sobel, Canny, operators and so on LOG. First as a whole introduced digital image processing and the edge detection survey, has enumerated several kind of at present commonly used edge detection technology and the algorithm, and selects two kinds to use Visual the C language programming realization, through withdraws the image result to two algorithms the comparison, the research discusses their good and bad points. 对图像边缘检测算法的研究学术报告摘要 数字图像处理作为一门相对比较年轻的学科, 伴随着计算机技术的飞速发展, 日益得到广泛的应用. 边缘作为图像的一种基本特征, 在图像识别,图像分割,图像增强以及图像压缩等的领域中有较为广泛的应用.图像边缘提取的手段多种多样,其中基于亮度的算法,是研究时间最久,理论发展最成熟的方法, 它主要是通过一些差分算子, 由图像的亮度计算其梯度的变化, 从而检测出边缘, 主要有Robert, Laplacian, Sobel, Canny, LOG 等算子. 首先从总体上介绍了数字图像处理及边缘提取的概况, 列举了几种目前常用的边缘提取技术和算法,并选取其中两种使用Visual C++语言编程实现,通过对两种算法所提取图像结果的比较,研究探讨它们的优缺点. First chapter introduction §1.1 image edge examination introduction The image edge is one of image most basic characteristics, often is carrying image majority of informations.But the edge exists in the image irregular structure and in