Optical Versus Video See-Through Head-Mounted Displays

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Lincoln Power TIG 275 焊接机说明书

ProcessesStick, TIGProduct NumberK2619-1K2619-2K2620-1K2618-1 Ready-Pak®Package See back for complete specs© Lincoln Global, Inc. All Rights Reserved.275TIG WELDERSInput Power (Voltage/Phase/Hertz)K2619-1/K2618-1:208/230/460/1/60K2619-2:460/575/1/60K2620-1:220-230/380-400/415/1/50/60Input Current at Rated Output208V:104460V:47220-230V:95575V:38230V:94380-400V:55415V:50Rated Output: Current/Voltage/Duty Cycle275A/31V/40%Weight/Dimensions (H x W x D)397 lbs. (180 kg)31 x 22 x 26 in.(787 x 559 x 660 mm)INPUT OUTPUTK2618-1 Includes:K2619-1Under-Cooler Cart Water Cooler –PH: +1.216-481-8100 • LI NC OL N E L E C TR ICShown K2619-1[ 2]|Precision TIG ®275What Is It?Pulse welding systems vary weld current between peak (high heat) and background current (low heat) levels. Adjusting the pulse frequency controls the level of heat input applied to the weld relative to the weld travel speed.ResultsBetter control of heat input in the weld, resulting in:•Reduced warping and burnthrough on thin materials. •Smaller heat-affected zone – good for thin material.•Smaller bead profile without compromising proper penetration.Easy “Set It/See It” Operation:•Flashing indicator light lets you see the pulse rate before you strike an arc.W e l d i n g C u r r e ntTimePulsed TIG Weld (at 60 amps)Standard TIG Weld (at 60 amps) Smaller HeatAffected ZoneSmaller Bead ProfileMicro-Start ™II Technology aids arc stabilityTHROUGHOUT THE WELD CYCLE – even at the lowest amperage! Micro-Start ™II Technologycontrolled ramp down helps precisely fill the weld crater for quality results.Micro-Start ™II Technology minimizes high frequency and ‘hot starts’ to deliver soft arc starts without arc wandering for AC and DC welding. Arc PerformanceMicro-Start ™Stable, Focused Arc Precise Crater Fill“Set It/See It” Pulse Control — Make attractive and consistent welds!N O WIN C L U D ESf o r A L UM IN U MW E L D INGA CPrecision TIG ®275| [ 3]AC Auto Balance ®Controls —Automatically sets the optimal cleaning vs. penetration level for aluminum welding!What Is It?When aluminum welding, the positive (+) portion of the AC weldingamperage cleans the oxides from the aluminum surface. The negative (-)portion delivers more heat input, increasing penetration level.Patented AC Auto Balance ®automatically sets the ratio of cleaning action (+) versus penetration (-) based on amperage.Manual balance control provides the flexibility to customize the arc to your preference.Easy Operation:•Set it and forget it or override when you choose to customize the settings.More Cleaning (+)Less Cleaning (+)Less Penetration(-)More Penetration (-)W E L D I N G W E L D I N G TIMETIMEMaximum Cleaning SettingMaximum Penetration SettingAuto Balance Setting•Fan-As-Needed (F.A.N.)™minimizes repeated heating and cooling of internal components, keeps dust and dirt build-up to a minimum and saves on electricity costs. •Engineered cooling air routing brings clean air in from the top and exhausts at the bottom to draw and collect less dirt in the machine. •Compare these reliability enhancing design features: — Crimped and soldered power connections.— Wound and varnished electrical coils do not require coil spacers used on competitive models. — Locking tabs on PC board connectors eliminates loose connections.•Tough testing cycles ensure long service — dropping, jerking,rolling, shipping, vibration, resistance to real world extreme conditions, and extended in-service life testing. •CSA C/US certified.•Lincoln three-year warranty on parts and labor.Clean, cool air route shown.Snap-action durable switches make positive mechanical contact to reduce chances ofintermittent contact failure.[ 4]| Precision TIG ®275Shown: K2618-1Water-Cooled Ready-Pak ®PackageTorch Parts Storage Compartment.Optional TIG pulsing helps you make great welds.Water-cooled torch connections with no adapters — side mounted to keep out of the way and protected.Neat/organized cable management with integratedtorch holster.Separate output studs for stick and TIG keep both stick electrode holder and TIG torch connected at the same time — eliminates set-up changeover when switching processes.Easily accessible input voltagereconnect panel.Low-Lift ™ Shielding Gas Bottle Platform.Lockable Undercarriage Storage and Water Cooler Drawers.Reliable Pro-Con Pump.Optional Features:(standard with K2618-1 Water-Cooled Ready-Pak ®Package)Precision TIG ®275| [ 5]Large, well-spaced controls make it easy to view and set upwith gloved hands.SET-UP MENUPress and hold the menu button to display up to seven programmable parameters. The setting of the desired level is displayed, and increasing or decreasing the level setting is easy.The Set-Up Menu includes:Standard•DC TIG Start Modes: High Frequency, Scratch Start, and Touch Start TIG ®.•Adjustable Preflow Time.•Adjustable Start Pulse for Soft or Forceful Starts.With Optional Advanced Control Panel •Adjustable TIG Hot Start.•Adjustable Upslope Time.•Adjustable Stick Hot Start.•Adjustable Stick Arc Force.A)Minimum Output Control & Display Switch (Also displays output voltage)B)Set-Up Menu (see below)C)Digital MeterD)Local/Remote Current Control Switch E)Maximum Output Control F)Post Flow Time G)Thermal Shutdown Light H)Optional Advanced Control Panel 1)Trigger Switch (2-step/4-step)2)Pulse/Spot Time Mode Switch 3)Pulse Frequency Control 4)Pulse % On Time Control 5)Pulse Background Current Control 6)Downslope Time, In Seconds 7)Spot Time I)Polarity Switch J)Power Switch K)AC Balance Control L)Mode SwitchH123 4 & 756BCDEAF G HI J KLC U S T O M E R A S S I S T A N C E P O L I C YThe business of The Lincoln Electric Company ®is manufacturing and selling high quality welding equipment, consumables, and cutting equipment. Our challenge is to meet the needs of our customers and to exceed their expectations. On occasion, purchasers may ask Lincoln Electric for information or advice about their use of our products. Our employees respond to inquiries to the best of their ability based on information provided to them by the customers and the knowledge they may have concerning the application. Our employees, however, are not in a position to verify the information provided or to evaluate the engineering requirements for the particular weldment. Accordingly, Lincoln Electric does not warrant or guarantee or assume any liability with respect to such information or advice. Moreover, the provision of such information or advice does not create, expand, or alter any warranty on our products. Any express or implied warranty that might arise from the information or advice, including any implied warranty of merchantability or any warranty of fitness for any customers’ particular purpose is specifically disclaimed.Lincoln Electric is a responsive manufacturer, but the selection and use of specific products sold by Lincoln Electric is solely within the control of, and remains the sole responsibility of the customer. Many variables beyond the control of Lincoln Electric affect the results obtained in applying these types of fabrication methods and service requirements.Subject to Change – This information is accurate to the best of our knowledge at the time of printing. Please refer to for any updated information.For best welding results with Lincoln Electric equipment,always use Lincoln Electric consumables. Visit for more details.GENERAL OPTIONSAdvanced Control Panel Provides 2/4-step trigger with adjustable Pulser controls and Downslope timer for TIG welding.Also includes adjustable Hot Start and Arc Force internal panel controls for stick welding, and other user selectable features.Order K2621-1Under-Cooler Cart Water Cooler Includes “cooler-in-a-drawer” with hoses and a lockable storage drawer on a dual bottle undercarriage. Two gallon (7.5 ltrs.) capacity.Order K1828-1UndercarriageIncludes a dual bottle rack with chain and front casters, rear wheels and a handle. Order K1869-1Harris ®Argon Flowmeter RegulatorDeluxe flowmeter/regulator. Includes 10 ft. (3.0 m) hose. Order 3100211Work Clamp & Cable Assembly 15 ft. 2/0 cable with 1/2 in. stud lug and work clamp. Order K2150-1STICK OPTIONSAccessory KitFor stick welding. Includes 35 ft.(10.7 m) 2/0 electrode cable with lug, 30 ft. (9.1 m) 2/0 work cable with lugs, headshield, filter plate,work clamp and electrode holder.400 amp capacity.Order K704Accessory KitFor stick welding. Includes 20 ft. (6.1 m) #6 electrode cable with lug,15 ft. (4.6 m) #6 work cable with lugs, headshield, filter plate, work clamp, electrode holder and sample pack of mild steel electrode. 150amp capacity.Order K875Remote Output ControlConsists of a control box with choice of two cable lengths. Permits remote adjustment of output. 6 pin connection.Order K857for 25 ft. (7.6 m)Order K857-1for 100 ft. (30.5 m) TIG OPTIONSMagnum®Pro-Torch™TIG TorchesA full line of air-cooled and water-cooled torches available.Request publication E12.150PTA-26 One-Cable AdapterAdapts the 7/8 in. PTA-26 fitting tothe 5/8 in. gas and powerconnection on machine. Order K2166-1PTA-9, -17 One-Cable Adapter Adapts the 3/8 in. PTA-9 or -17fitting to the 5/8 in. gas and power connection on machine.Order K2166-3PTA-9, PTA-17, PTA-26 Two-Cable AdapterConverts the 7/8 in. water andpower connection on the machine to a 1/2 in. output stud for use with a two-cable air-cooled TIG torch.Order K2166-2Foot Amptrol ™Varies current for making critical TIG welds. Depress pedal to increase current. Depressing pedal fullyachieves maximum set current. Fully raising the pedal finishes the weld and starts the afterflow cycle.Includes 25 ft. (7.6 m) control cable.6-pin plug connection.Order K870Hand Amptrol ™Provides 25 ft. (7.6 m) of remote current control for TIG welding (6 pin plug connection). Velcro straps secure torch.Order K963-3(One size fits all Pro-Torch ™TIG Torches.)Arc Start SwitchNeeded if an Amptrol ™is not used when TIG welding. Comes with a 25ft. (7.6 m) cable. Attaches to the TIG torch for convenient finger control. 6-pin plug connection. Order K814Cut Length Consumables TIG welding filler metals are available for welding stainless steel, mild steel, aluminum and copper alloys.See publication C1.10。

EE-SPZ401-A和EE-SPY402摄像头传感器说明书

FUNCTION: Reflective tape strips are positioned behind the wheel and used to activate the photomicrosensors for each betting category on the wheel. The on/off state of each sensor acts as part of a binary code, so that the position and number of tape strips on each portion of the wheel form a distinct code which makes the correct light on the table flash.
PCB Hole Detection
APPLICATION: With its built-in microprocessor, the Z4D-F04A/D is able to attain a 5 μm resolution. The 5 μm resolution of the Z4D-F04A/D make them ideal for use in detecting holes in printed circuit boards.
Robot Control
APPLICATION: Use the EE-SX470/670, EE-SX770/870 and EE-SPX740/840 series of sensors to detect end of travel and positioning on robot controlled devices. These slotted sensors can provide return--to--origin confirmation and home position detection.

NANO mXTEND 迷你高效蓝牙 Wi-Fi天线说明书

NANO mXTEND TM: MINIATURE AND HIGH EFFICIENCY BLUETOOTH/WI-FI ANTENNAUSER MANUALNANO mXTEND TM (NN02-101)NANO mXTEND TMMINIATURE AND HIGH-EFFICIENCY BLUETOOTH/WI-FIANTENNANN02-101NANO mXTEND TM | Bluetooth & Wi-Fi Operating range: 2400 – 10600 MHzBest for: 2400 – 2500 MHzDimensions : 3.0 mm x 2.0 mm x 0.8 mmWhat is the NANO mXTEND TM?The NANO mXTEND TM is the smallest Virtual Antenna® chip to date. Featuring a size of only 3 mm x 2 mm x 0.8 mm, this off-the-shelf chip antenna has been designed to fit almost every IoT device from entry-level to high-end products. The NANO mXTEND TM is enabled by Virtual Antenna® technology, thus featuring the unique properties of this class of products: easy to use; versatile, and broadly tunable. The NANO mXTEND TM is available for Bluetooth, Wi-Fi, Wi-SUN, and any wireless connectivity protocol operating in the 2.4 - 2.5 GHz band. Due to Ignion’s proprietary Virtual Antenna® technology, this chip antenna is non-resonant and therefore broadly tunable, enabling additional frequency bands to be supported by the same antenna part and released in the future.As with every other Virtual Antenna® chip, the NANO mXTEND TM is available through Ignion’s Antenna Intelligence Cloud tool, enabling predictable design and performance throughout the entire product development cycle. Moreover, the NANO mXTEND TM is built on a glass epoxy substrate, making its manufacturing broadly available and therefore resilient against shortage.Material: The NANO mXTEND TM antenna booster is built on a glass epoxy substrate.What is the NANO mXTEND TM used for?The NANO mXTEND TM is suitable for embedding an antenna into any wireless device requiring optimum performance in a small, cost-effective package for operating in the Bluetooth/Wi-Fi/Wi-SUN ISM 2.4 GHz frequency bands, including:▪Asset Trackers▪Smart Tags▪Earphones and Headsets ▪Wearables▪Logistic Trackers▪Health sensors ▪Animal Trackers▪Security Sensors▪Service Buttons▪Environmental Sensors ▪IoT Developer Kits▪Wireless Sniffing SensorsWhat differentiates the NANO mXTEND TM from other chip antennas?Like every other Virtual Antenna® product, the NANO mXTEND TM is frequency neutral, meaning that its frequency response is not determined by the antenna component but designed by the electronics engineer. Virtual Antenna® technology provides the broadest range of connectivity options with desired antenna performance in the smallest ever form factor. This unique technology enables the whole mXTEND TM range of components to become tiny, off-the-shelf, surface-mount (SMD) electronic chips while still providing connectivity with multiple frequency bands and meeting the requirements of most wireless devices’ architectures and form factors. Being non-resonant, the whole antenna performance can be customized through a shorter and easier design cycle by means of a matching circuit, while benefiting at the same time from a robust, reliable, and cost-effective manufacturing process because of the chip, SMD form factor. Also, the NANO mXTEND TM‘s architecture is not using ceramic materials to achieve miniaturization, which ensures a pervasive availability of raw materials thus making the supplychain resilient to shortage and price fluctuations.HOW TO EMBED A VIRTUAL ANTENNA®MECHANICAL SPECIFICATIONSASSEMBLY AND MANUFACTURINGPACKAGINGThe NANO mXTEND TM for Bluetooth/Wi-Fi 9 CORNER MOUNTING CONFIGURATION 9 MATCHING NETWORK 11 VSWR AND TOTAL EFFICIENCY 12 RADIATION PATTERNS, GAIN, AND EFFICIENCY 13 EDGE MOUNTING CONFIGURATION 14 MATCHING NETWORK 15 VSWR AND TOTAL EFFICIENCY 16 RADIATION PATTERNS, GAIN, AND EFFICIENCY 17 MECHANICAL SPECIFICATIONS 18 DIMENSIONS, TOLERANCES, AND RoHS 18 INK COLOR RANGE 18 RECOMMENDED FOOTPRINT FOR THE NN02-101 19 ASSEMBLY AND MANUFACTURING 21PACKAGING 23How to embed Virtual Antenna ®Design with Virtual Antenna ® in 1-2-3https://ignion.io/design-center/tutorials-webinars/STEP 2: Design your matching network1. Through a combination of inductors & capacitorsobtain 50 Ohms of antenna impedance to optimize the transfer of energy to your antenna2. It is critical to fine-tune your MN throughout theentirety the design process to achieve your desired frequency responseLook here for an example of a matching network for a Virtual Antenna ® product application via simulation Scan this QR code to see our videos highlighting these three easy stepsNeed further help? Easy start with Antenna Intelligence CloudDo you need more help with your antenna for your device?Use our Antenna Intelligence Cloud service and get your ready-to-test, proof-of-concept antenna design especially simulated for your platform free of charge 1, and in 24 hours .https://www.ignion.io/antenna-intelligence/1 Subject to terms and conditions here .Scan QR code to be taken to our AntennaIntelligence Cloud pageThe NANO mXTEND™ has been designed for Bluetooth/Wi-Fi connectivity at 2.4 GHz. An optimum tuning of this chip at the 2.4 GHz band is achieved through a matching network. Due to its versatility, the chip antenna component can be mounted both on the corner or on the center of an edge of the printed circuit board (PCB) of your wireless device just by changing the matching network. The table below includes a quick reference guide for the antenna specifications on a reference design of 80 x 40 mm, as well as the set-up matching network and performance for both a corner and an edge mounting configuration.QUICK REFERENCE GUIDETechnical Specs for the NANO mXTEND™ in the corner configuration: Technical features 2400 – 2500 MHzAverage Efficiency >55 %Peak Gain 2.4 dBiVSWR < 2.5:1Radiation Pattern OmnidirectionalPolarization LinearWeight (approx.) 0.01 g.Temperature -40 to +125 ºCImpedance 50 ΩDimensions3.0 mm x 2.0 mm x 0.8 mm(L x W x H)Table 1 – Technical Features. Measurements from the evaluation board (Figure 1) Technical Specs for the NANO mXTEND™ in the edge configuration: Technical features 2400 – 2500 MHzAverage Efficiency >65 %Peak Gain 2.4 dBiVSWR < 3.0:1Radiation Pattern OmnidirectionalPolarization LinearWeight (approx.) 0.01 g.Temperature -40 to +125 ºCImpedance 50 ΩDimensions3.0 mm x 2.0 mm x 0.8 mm(L x W x H)Table 2– Technical Features. Measurements from the evaluation board (Figure 4)CORNER MOUNTING CONFIGURATIONThe NANO mXTEND TM is ready and recommended for corner mounting in those devices where this region is available for antenna placement. This section details a corner mounting design on a reference ground plane of 80 mm x 40 mm including a clearance area of 5 mm x 5 mm (Figure 1). Other ground plane sizes and clearances can be implemented by adapting the matching network.MeasuremmA 80B 75C 40D 5E 5 F3Tolerance : ±0.2 mmD: Length of clearance area.Figure 1 - EB_NN02-101_c_BT. Evaluation board configured to provide operation at Bluetooth (2400 – 2500MHz).This product and its use are protected by at least one or more of the following patents and patent applications PAT. US 62/529032; and other domestic and international patents pending.MATCHING NETWORKThe NANO mXTEND TM antenna booster needs a matching network to ensure optimal performance in the 2.4 GHz – 2.5 GHz frequency range. This section presents a suitable matching network for the corner mounting configuration (Figure 7). Please note that different form factors, RF ground planes, and nearby components may require a different matching network.If you need assistance to design your matching network beyond this application note, please contact *****************, or if you are designing a different device size or a different frequency band, we can assist you in less than 24 hours. Please, try our free-of-charge1 Antenna Intelligence Cloud, which will get you a complete design report including a custom matching network for your device in 24h1. Additional information related to Ignion’s range of R&D services is available at: https://ignion.io/rdservices/2.4 GHz – 2.5 GHz8.7 nH LQW18AN8N7G808.2 nH LQW18AN8N2C805.8 nH LQW15AN5N8B80Figure 2 –Matching network implemented on the Evaluation Board (Figure 1) for covering Bluetooth from 2.4GHz to 2.5GHz.For an optimal result, the use of high-quality factor (Q) and tight tolerance components is highly recommended (e.g., Murata components with part numbers as shown in Figure 2). The antenna performance is always conditioned by its operating environment meaning that differences in the device, including differences in printed circuit board sizes, components near the antenna, displays, batteries, covers, connectors, etc. affect the antenna performance. Accordingly, placing pads compatible with 0402 and 0603 SMD components for a matching network as close as possible to the feeding point of the antenna element is highly recommendable. It is also recommendable to do this in the ground plane area, not in the clearance area. By tuning the matching network in your final design after your final surrounding components are in place (batteries, displays, covers, etc.) you will be able to optimize the antenna performance without changing the antenna part or the design.1 See terms and conditions for a free Antenna Intelligence Cloud service in 24h at:https://www.ignion.io/antenna-intelligence/VSWR (Voltage Standing Wave Ratio) and Total Efficiency versus Frequency (GHz).Figure 3 - VSWR and Total Efficiency for the 2.4 – 2.5 GHz frequency range as observed on the evaluation board EB_NN02-101_c_BT (Figure 1).2.4 – 2.5GHzNANO mXTEND™ ɳa 2400MHzɳa 2500MHz Min Max Av. ɳaOn the corner 54.9 57.1 54.9 63.2 60.1 Table 3 - Antenna efficiency comparison considering the evaluation board EB_NN02-101_c_BT (Figure 1).The NANO mXTEND TM operates at the required Bluetooth/Wi-Fi frequency spectrum with high-efficiency values. Please note that its high performance can be sustained even with a reducedclearance area.RADIATION PATTERNS, GAIN, AND EFFICIENCYMeasurement System Set-UpEvaluation Board in Plane XYθ = 90º Plane XY at 2450 MHzφ= 0º Plane XZ at 2450 MHzφ= 90º Plane YZ at 2450 MHz GainPeak Gain 2.4 dBiAverage Gain across the band 2.2 dBiGain Range across the band (min, max) 1.9 dBi <–> 2.4 dBi EfficiencyPeak Efficiency 75.4 %Average Efficiency across the band 71.9 %Efficiency Range across the band (min, max) 66.3 – 75.4 %Table 4 – Antenna Gain and total efficiency from the evaluation board (Figure 1) Bluetooth band. Measurements made in the STARLAB 18 anechoic chamber.EDGE MOUNTING CONFIGURATIONIn devices such as dual-hand gaming handhelds and landscape handheld devices, the center of the edge can be the ideal placement area for your chip antenna, This section details a design example and evaluation board (80 mm x 40 mm with 4 mm x 4 mm of ground clearance) in such an edge mounting configuration (Figure 4).MeasuremmA 80B 40 C5Tolerance : ±0.2 mmC: Length of clearance area.Figure 4 - EB_NN02-101_m_BT. Evaluation board providing operation at Bluetooth (2400 – 2500 MHz).MATCHING NETWORKBy simply changing the matching network, the NANO mXTEND TM can also deliver optimal performance in an edge mounting configuration. A suitable matching network for edge mounting in the reference board pictured above is shown in Fig.5. Please note that different form factors of your wireless device and its RF ground planes, and the proximity of other elements such as shields, covers, connectors and the like might result in the need for a fine-tuning of the matching network.If you need assistance to design your matching network beyond this application note, please contact *****************, or if you are designing a different device size or a different frequency band, we can assist you in less than 24 hours. Please, try our free-of-charge1 Antenna Intelligence Cloud, which will get you a complete design report including a custom matching network for your device in 24h2. Additional information related to Ignion’s range of R&D services is available at: https://ignion.io/rdservices/2.4 GHz – 2.5 GHz--0.4pF GJM1555C1HR40WB010.3pF GJM1555C1HR30WB010.3pF GJM1555C1HR30WB01Figure 5 –Matching network implemented in the Evaluation Board (Figure 4) for covering Bluetooth from 2.4GHz to 2.5GHz.To ensure optimal results, the use of high-quality factor (Q) and tight tolerance components is highly recommended (e.g. Murata components with part numbers as shown in Figure 5). The antenna performance is always conditioned by its operating environment meaning that differences in the device, including differences in printed circuit board sizes, components near the antenna, displays, batteries, covers, connectors, etc. affect the antenna performance. Accordingly, placing pads compatible with 0402 and 0603 SMD components for a matching network as close as possible to the feeding point of the antenna element is highly recommendable. It is recommended to do this in the ground plane area, not in the clearance area. By tuning the matching network in your final design after your final surrounding components are in place (batteries, displays, covers, etc.) you will be able to optimize the antenna performance without changing the antenna part, or the design.2 See terms and conditions for a free Antenna Intelligence Cloud service in 24h at:https://www.ignion.io/antenna-intelligence/VSWR (Voltage Standing Wave Ratio) and Total Efficiency versus Frequency (GHz).Figure 6 - VSWR and Total Efficiency for the 2.4 – 2.5 GHz frequency range configured to provide operation the evaluation board EB_NN02-101_m_BT (Figure 4).2400 – 2500 MHzNANO mXTEND™ ɳa 2400MHzɳa 2500MHz Min Max Av. ɳaOn the middle 60.1 63.6 60.1 77.3 71.7 Table 5 - Antenna efficiency comparison configured to provide operation the evaluation board EB_NN02-101_m_BT (Figure 4).The NANO mXTEND TM operates at the required Bluetooth/Wi-Fi frequency spectrum with high efficiency values. Please note that its high performance can be sustained even with the small5x5 mm clearance area.RADIATION PATTERNS, GAIN, AND EFFICIENCYMeasurement System Set-UpEvaluation Board in Plane XYθ = 90º Plane XY at 2450 MHzφ = 0º Plane XZ at 2450 MHzφ = 90º Plane YZ at 2450 MHzGainPeak Gain1.1 dBi Average Gain across the band0.85 dBi Gain Range across the band (min, max) 0.3 dBi <–> 1.1 dBiEfficiencyPeak Efficiency73.7 % Average Efficiency across the band69.6 % Efficiency Range across the band (min, max)70.0 – 73.7 %Table 6 – Antenna Gain and total efficiency from the evaluation board (Figure 4) Bluetooth band. Measurements made in the STARLAB 18 anechoic chamber.MECHANICAL SPECIFICATIONSDIMENSIONS, TOLERANCES, AND RoHSTOPSIDEBOTTOMDimensionmm DimensionmmA2.0 B3.0 C 0.25 D 1.0 E 0.5 F 1.3 G 0.6 H 0.8 I0.35J0.8Figure 7 - NANO mXTEND TM antenna booster dimensions and tolerances.The NANO mXTEND TM (NN02-101) antenna booster is compliant with the restriction of the use of hazardous substances (RoHS ). For more information, please contact **************.INK COLOR RANGEThe next figure shows the range of colors in the NANO mXTEND TM antenna booster:Acceptable color rangeRECOMMENDED FOOTPRINT FOR THE NN02-101See below the recommended footprint dimensions for the NANO mXTEND TM (NN02-101) antenna booster on the corner .MeasuremmA 1.0B 0.5C 1.3D 0.8 E0.15Tolerance : ±0.05mmFigure 8 - Footprint dimensions for the NANO mXTEND™ (NN02-101) antenna booster (on the corner).See below the recommended footprint dimensions for the NANO mXTEND T M (NN02-101) antenna booster in the middle .Tolerance : ±0.05mmMeasuremmA 1.875B 1.35C 0.5D 1.0E 3.15 F4.0Figure 9 - Footprint dimensions for the NANO mXTEND™ (NN02-101) antenna booster (on the middle).For additional support in the integration process, please contact *****************.ASSEMBLY AND MANUFACTURINGFigure 10 shows the back and front views of the NANO mXTEND TM(NN02-101) antennabooster.Figure 10 – Pads of the NANO mXTEND TM (NN02-101)antenna booster.As a surface mount device (SMD), the NANO mXTEND TM antenna booster is compatible withindustry standard soldering processes. The basic assembly procedure for the NANOmXTEND TM antenna booster is as follows:1. Apply a solder paste on the pads of the PCB. Place the NANO mXTEND TM antenna boosteron the board.2. Perform a reflow process according to the temperature profile detailed in Figure 11.3. After soldering the NANO mXTEND TM antenna booster to the circuit board, perform acleaning process to remove any residual flux. Ignion recommends conducting a visualinspection after the cleaning process to verify that all reflux has been removed.The figure below shows the soldering details obtained after a correct assembly process:Figure 11 - Soldering detailsNOTE (*): Solder paste thickness after the assembly process will depend on the thickness of the soldering stencil mask. A stencil thickness equal to or larger than 127 microns (5 mils) isrequired.The NANO mXTEND TM (NN02-101) antenna booster can be assembled following the Pb-free assembly process. According to the IPC/JEDEC J-STD-020C Standard, the suggested temperature profile is as follows:Phase Profile featuresPb-Free assembly (Sn Ag Cu) RAMP-UPAvg. Ramp-up Rate (Tsmax to Tp) 3 ºC / second (max.) PREHEAT- Temperature Min (Tsmin)- Temperature Max (Tsmax) - Time (tsmin to tsmax)150 ºC 200 ºC60-180 seconds REFLOW- Temperature (TL) - Total Time above TL (tL) 217 ºC60-150 seconds PEAK - Temperature (Tp) - Time (tp) 260 ºC 20-40 seconds RAMP-DOWNRate6 ºC/second max Time from 25 ºC to Peak Temperature8 minutes maxTable 7 – Recommended soldering temperatures.The next graphic shows the temperature profile (grey zone) for the NANO mXTEND TM antenna booster assembly process reflow ovens.Figure 12 – Temperature profilePACKAGINGThe NANO mXTEND TM (NN02-101) antenna booster is delivered in tape and reel packaging.Measure mm A0 3.6 ± 0.1 B0 7.5 ± 0.1 K0 2.5 ± 0.1 W 16.0 ± 0.3 P 8.0 ± 0.1 T 0.3 ± 0.05Figure 13 -Tape dimensions and tolerances.Reel Capacity : 2500 pcsMeasure Mm A 330 ± 1.0 G 16.4 ± 0.1 t max20.4 ± 0.1Figure 14 - Reel dimensions and capacity.Ignion products and solutions are protected by Ignion patents .All information contained within this document is property of Ignion and is subject to change without prior notice. Information is provided “as is” and without warranties. The copy or reproduction of this information without prior approval is prohibited.Ignion is an ISO 9001:2015 certified company. All our antennas are lead-free and RoHS compliant.ISO 9001: 2015 CertifiedContact:***************** +34 935 660 710BarcelonaAv. Alcalde Barnils, 64-68 Modul C, 3a pl. Sant Cugat del Vallés08174 BarcelonaSpainShenzhenTopway Information Building，2303 Room No.3369, Binhai Avenue, Nanshan District Shenzhen, Guangdong 518000China+86138****8470Tampa8875 Hidden River ParkwaySuite 300Tampa, FL 33637USA。

托福阅读tpo38R-1原文+译文+题目+答案+背景知识

托福阅读tpo38R-1原文+译文+题目+答案+背景知识原文Microscopes①Before microscopes were first used in the seventeenth century,no one knew that living organisms were composed of cells.The first microscopes were light microscopes,which work by passing visible light through a specimen.Glass lenses in the microscope bend the light to magnify the image of the specimen and project the image into the viewer's eye or onto photographic film.Light microscopes can magnify objects up to1,000times without causing blurriness.②Magnification,the increase in the apparent size of an object,is one important factor in microscopy.Also important is resolving power,a measure of the clarity of an image.Resolving power is the ability of an optical instrument to show two objects as separate.For example,what looks to the unaided eye like a single star in the sky may be resolved as two stars with the help of a telescope.Any optical device is limited by its resolving power.The light microscope cannot resolve detail finer than0.2micrometers,about the size of the smallest bacterium; consequently,no matter how many times its image of such a bacterium is magnified,the light microscope cannot show the detailsof the cell's internal structure.③From the year1665,when English microscopist Robert Hooke discovered cells,until the middle of the twentieth century,biologists had only light microscopes for viewing cells.But they discovered a great deal,including the cells composing animal and plant tissues, microscopic organisms,and some of the structures within cells.By the mid-1800s,these discoveries led to the cell theory,which states that all living things are composed of cells and that all cells come from other cells.④Our knowledge of cell structure took a giant leap forward as biologists began using the electron microscope in the1950s.Instead of light,the electron microscope uses a beam of electrons and has a much higher resolving power than the light microscope.In fact,the most powerful modern electron microscopes can distinguish objects as small as0.2nanometers,a thousandfold improvement over the light microscope.The period at the end of this sentence is about a million times bigger than an object0.2nanometers in diameter,which is the size of a large atom.Only under special conditions can electron microscopes detect individual atoms.However,cells,cellular organelles, and even molecules like DNA and protein are much larger than single atoms.⑤Biologists use the scanning electron microscope to study the detailed architecture of cell surfaces.It uses an electron beam to scan the surface of a cell or group of cells that have been coated with metal. The metal stops the beam from going through the cells.When the metal is hit by the beam,it emits electrons.The electrons are focused to form an image of the outside of the cells.The scanning electron microscope produces images that look three-dimensional.⑥The transmission electron microscope,on the other hands,is used to study the details of internal cell structure.Specimens are cut into extremely thin sections,and the transmission electron microscope aims an electron beam through a section,just as a light microscope aims a beam of light through a specimen.However,instead of lenses made of glass,the transmission electron microscope uses electromagnets as lenses,as do all electron microscopes.The electromagnets bend the electron beam to magnify and focus an image onto a viewing screen or photographic film.⑦Electron microscopes have truly revolutionized the study of cells and cell organelles.Nonetheless,they have not replaced the light microscope.One problem with electron microscopes is that they cannot be used to study living specimens because the specimen must be held in a vacuum chamber;that is,all the air and liquid must beremoved.For a biologist studying a living process,such as the whirling movement of a bacterium,a light microscope equipped with a video camera might be better than either a scanning electron microscope or a transmission electron microscope.Thus,the light microscope remains a useful tool,especially for studying living cells.The size of a cell often determines the type of microscope a biologist uses to study it.译文显微镜①在十七世纪首次使用显微镜之前，没有人知道生物是由细胞组成的。

Mars说光场（4）—光场显示

Mars说光场（4）—光场显⽰沉浸感按：光场技术是⽬前最受追捧的下⼀代显⽰技术，⾕歌、Facebook、Magic Leap等国内外⼤公司都在⼤⼒布局。

然⽽⽬前国内对光场（Light Field）技术的中⽂介绍⼗分匮乏，曹煊博⼠《Mars说光场》系列⽂章旨在对光场技术及其应⽤的科普介绍。

曹煊博⼠系腾讯优图实验室⾼级研究员。

优图— 腾讯旗下顶级的机器学习研发团队，专注于图像处理、模式识别、深度学习。

在⼈脸识别、图像识别、医疗AI、OCR、哼唱识别、语⾳合成等领域都积累了领先的技术⽔平和完整解决⽅案。

《Mars说光场》系列⽂章⽬前已有5篇，包括：《Mars说光场（1）— 为何巨头纷纷布局光场技术》；《Mars说光场（2）— 光场与⼈眼⽴体成像机理》；《Mars说光场（3）— 光场采集》；《Mars说光场（4）— 光场显⽰》；《Mars说光场（5）— 光场在三维⼈脸建模中的应⽤》；沉浸感经授权发布。

重现⼀个真实的三维世界，实现类似于《阿凡达》电影所展⽰的全息显⽰，是⼈类长久以来的梦想。

如果能采集并投射出全光函数中7个维度的光线，将能使环境中所有⼈同时获得⾝临其境的全息视觉体验。

光场作为理想的3D显⽰技术与传统2D显⽰有着明显的区别：传统的2D显⽰器只能提供仿射、遮挡、光照阴影、纹理、先验知识五⽅⾯⼼理视觉信息。

光场显⽰除了能产⽣传统2D显⽰器的所有信息外，还能提供双⽬视差、移动视差、聚焦模糊三⽅⾯的⽣理视觉信息。

在光场显⽰技术发展过程中，出现了多种光场显⽰技术⽅案，引起⼴泛关注和研究的主要有五种技术：（1）体三维显⽰（Volumetric 3D Display）；（2）多视投影阵列（Multi-view Projector Array）；（3）集成成像（Integral Imaging）；（4）数字全息；（5）多层液晶张量显⽰。

关于三维显⽰的详细发展历史及其应⽤可以参见[1-11]。

图 1. 电影《阿凡达》中描绘的光场全息三维军事沙盘⼀体三维显⽰体三维显⽰技术[12,13]主要通过在空间中不同深度平⾯显⽰不同图像来实现。

【2025届上海高三一模英语】2025届上海市黄浦区高三英语一模试卷及答案

上海市黄浦区2024-2025学年第一学期高三期末质量监控·英语试卷（完卷时间：105分钟满分：115分）笔试部分：第I卷（共75分）Ⅰ. Grammar and VocabularySection ADirections: After reading the passage below, fill in the blanks to make the passages coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blank.The Ancient Philosophy Behind The SignThe Sign, a 28-minute episode of the kids TV show has been hotly anticipated –and its story is a deep reflection on change.The much-loved Australian cartoon about Bluey, a seven-year-old blue dog has been a worldwide phenomenon since it (1) (launch) back in 2018. Alongside more genuinely laugh-out-loud moments than in most high-time comedies, it contains more serious elements too, such as brief introductions of parenting situations (2) will be painfully familiar to any guardians or caregivers, as well as inferences to fateful life events (3) death and marriage. It’s exploring an adult world with the joyous, surreal excitement of childhood.(4) viewers won’t have predicted will be how much this episode draws from Taoist philosophy. It is an ancient Chinese belief system based on trying (5) (exist) in harmony with the universe. When Bluey sadly tells her classmates she’s moving away, her teacher Calypso reads a story (6)(call)The Farmer. The story follows a series of events happening, and each time, the neighbours tell the farmer thatit’s “good luck” or “bad luck”. Every time, the farmer simply replies to each situation, “We’ll see”. “Is it a happyor sad ending?” asks Bluey afterwards. “Both,” says Calypso. “I don’t understand,” says Bluey. “Everything will work out the way that (7) is supposed to, Bluey,” she replies.The story is actually an old tale that first originated in the Huainanzi, an ancient Chinese text (8) (date) back to 139 BC, and it reminds people that we have no control or no real way of knowing whether events that happen to us (9) (be) “good” or “bad”. (10)we are open to change and trust that things will work out for the best, we are sure to make it.Section BDirections: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.How to Get the Most Out of Alone TimeSolitude is a state of being alone or away from others. It is distinct from loneliness, a feeling of emptinessor sadness arising from a perceived lack of desired connection with others. While we think of loneliness as a negative emotional state, solitude can be a positive and 11 experience.As social creatures, we are conditioned to live in groups and seek approval and belonging. If we spend too much time alone, we can become 12 awkward, making it even harder to connect with others and get feedback from those around us. If you cannot be alone, you may stay in situations or make life choices that aren’t good for you in the long run, mainly because you can’t 13 being alone while transitioning to a better situation.Consider solitude a time for self-reflection, relaxation, creativity, and personal growth. It can allow you to focus on your thoughts and feelings, gain 14 on personal challenges, and develop a deeper understanding of yourself. Solitude can also be a way to 15 and find peace amid the demands and distractions of modern life.It’s essential to 16 a balance between solitude and social interaction. Different individuals have 17 needs for solitude, and finding the right amount that matches your well-being is essential for leading a fulfilling life. You’d better 18daily time for solitude. Plan some time to be with yourself daily to enjoy the benefits of solitude. For instance, at lunchtime, go for a walk by yourself and come back 19. Be aware of self-judgments about taking time for yourself. Wanting to be alone can be seen as 20 or anti-social; you should think about others and do things for them instead. Kindly challenge these self-judgments and respond to them with positive statements, like that taking time for oneself is essential for self-care and mental health.Ⅱ. Reading ComprehensionSection ADirections: For each blank in the following passages there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.Our drive to seek out happiness is a muscle that we can exercise and develop. Almost anyone can learn to develop their reward sensitivity by 21 themselves to notice and experience their positive emotions.To raise your reward sensitivity, begin by planning one activity per day that will make you happy or give you a sense of 22. It can be as small as treating yourself to a favorite snack or reading a few pages of a novel. This will make you less likely to 23 positive experiences. After you’ve enjoyed that 24 moment, close your eyes and recount out loud where and when you experienced the greatest joy. The idea isn’t just to remember how you felt, but to enhance and re-experience it, thus 25 your memory of them, and increasing your motivation to seek them out going forward.Here are some other adjustments you can make to develop a positive mind-set.Expand your joy 26: Research suggests that finding more words to describe positive emotions can prove and increase them. When reflecting on how something made you feel, try to be 27 , using words like calm, overjoyed, delighted, inspired beyond fine, good or great.Share your highlight reel(高光时刻): 28 what made you happiest can make you feel better. Spread that happiness to another person — and also strengthen a bond.Find bright sides: With practice, it’s possible to 29 the positives hidden in things that we might first see as negative. For example, if you invited co-workers to get together and only one person showed up, you could easily view that as a(n) 30 . But the bright side would be that you got to know that one person better.Forecast future wins: If you’re tight scheduled, pick an event that’s approaching and think of the best possible31 . If you’re tired, 32 smiling at your friend across the room, feeling proud. Using imagery can encourage motivation and get you ready for more 33 experiences.Keep in mind, too, that it’s normal to feel 34 with pleasurable feelings sometimes, particularly if you experience depression and anxiety. Worrying can make you feel like you’re ready to respond to threats —but by constantly 35 disaster, we miss the happiness in front of us right now. Sometimes we need to behave like happy people if we actually want to be happy.21. A. attracting B. demonstrating C. entertaining D. training22. A. accomplishment B. belonging C. identity D. responsibility23. A. broaden B. postpone C. provide D. share24. A. critical B. daily C. rare D. spare25. A. recalling B. recovering C. searching D. strengthening26. A. reflection B. selection C. trial D. vocabulary27. A. brief B. creative C. precise D. secure28. A. Broadcasting B. Choosing C. Defining D. Wondering29. A. cover B. divide C. teach D. notice30. A. failure B. opportunity C. reward D. surprise31. A. initiative B. outcome C. prize D. solution32. A. avoid B. imagine C. practice D. try33. A. direct B. inspiring C. sensory D. shared34. A. content B. distracted C. easy D. uncomfortable35. A. ending in B. guarding against C. heading for D. preparing forSection BDirections: Read the following three passages. Each passage is followed by several questions or unfinished statements. For each of them there are four choices marked A, B, C and D. Choose the one that fits best according to the information given in the passage you have read.(A)How much ongoing joy can you get from something that weighs eight ounces(盎司)? For Simon Spichak,it’s a lot, thanks to a hedgehog that fits in his hand.Mr. Spichak, a 29-year-old science writer who lives in Toronto, bought his new partner in May2023 for $280 and named it Goober. He has spent an additional $200 on food, a wheel, bedding andtoys, as well as $150 in their first year together to visit a veterinarian(兽医).Goober has improved Mr. Spichak’s life in small and big ways, providing him with entertainingmaterial to post to his social media accounts and helping to introduce him to some ofhis neighbors when he takes Goober around his block, where they’re met with delighted curiosity. “Thereare lots of people walking by from the neighborhood who start conversations because of the hedgehog,” Mr.Spichak said.This is not an individual case.Ritesh Seth, a human resources specialist in Columbia, Md., bought a solid brass, Italian-made coffee pot for $400, and said it had helped him expand his network at his co-working space.“Other business enterprises and start-ups who work out of the office space have noticed my coffeepot and out of curiosity come over to chat,” Mr. Seth, 38, said. “Usually, after the polite introductions, we discuss what product or project we are working on, find common business challenges, refer potential prospects and som etimes talk about sports.”Millennials (born from 1981 to 1996) and Generation Z (born from 1997 to 2012) are more likely than older generations to make spending on nonessential purchases a priority, according to a study published last year by Intuit. The study suggested that this was because younger generations placed a high value on personal growth and mental happiness. While gym memberships or self-help books may be more obvious purchases for improving lives, less typical options, even unusual ones, can make a lasting difference by helping people findhappiness and connect to new communities.36.What did Goober bring to Simon?A.It inspired him to pursue a science writing career.B.It helped him save money on veterinary expenses.C.It enriched his social media and neighborhood connections.D.It gained him fame by achieving recognition in the community.37.With the coffee pot as , Ritesh expanded his network at his co-working space.A. a conversation starterB. a marketable productC. a pilot projectD. a technical challengepared with older generations, Millennials and Generation Z .A.spend more time on gym memberships and self-help booksB.prefer to spend on non-essential items for self-growth and emotional joyC.favour financial security over personal development and mental happinessD.show less interest in connecting to new communities through unique items39.Which of the following is the best title for this passage?A.Business-Generation ToolsB. Career-Pursuit ChoicesC. Community-Service PetsD. Life-Improvement Purchases(B)Learning outcomesThis chapter gives you opportunities to:✓u nderstand what critical thinking is✓f ind out about the early roots and later developments of critical thinking✓r ecognize some of the benefits associated with critical thinking skills✓r ecognize the personal qualities connected to critical thinking✓r ecognize barriers to the development of good critical thinking skills✓a ssess your current understanding of critical thinking and identify your priorities for improvementIntroductionThis chapter provides a general introduction to critical thinking. It examines what is meant by “critical thinking”, the skills associated with it, and the barriers that can slow down effective development of critical approaches. Many people can find it difficult to order their thoughts in a logical, consistent and reasoned way. This book starts from the idea that skills in reasoning can be developed through a better understanding of what critical thinking involves, and by practice.Critical thinking is a cognitive activity connected to using the mind. Learning to think in critically analytical and evaluative ways means using mental processes such as attention (concentrating on specific details and information), categorization (the process of organizing information into categories based on shared characteristics), selection (selecting relevant information), and judgement (the ability to assess and form well-reasoned conclusions or opinions based on available evidence). However, many people who have the potential to develop more effective critical thinking can be prevented from doing so for a variety of reasons apart from a lack of ability. In particular, personal and emotional, or “affective”, reasons can create barriers.You are invited to consider, in this chapter, how far such barriers could be affecting your own thinking abilities and how you will manage them.40.According to the learning outcomes, which of the following topics is most likely to be included in Chapter 1?A.Significant works in critical thinkingB.Teaching strategies for critical thinkingC.Critical thinking: individual or collective?D.Critical thinking: Where does it come from?41.What can a reader learn in this chapter?A.How a mental process works and what role it plays in making logical reasoning.B.What defines cognitive activity and how emotions can shape critical thinking skills.C.Why individuals possess varying abilities to think critically and how to assess them.D.What is critical thinking and how it can be developed through understanding and practice.42.Which of the following examples best illustrates the mental process of categorization?A.A student chooses articles that are related to his topic from a large database.B.A student focuses on the main points the teacher emphasizes in a physics class.C.A student sorts notes by grouping them according to different historical periods.D.A student decides which arguments to include in his essay after weighing the evidence.(C)①I read “Middlemarch” in college. None in my class got it. Why would Dorothea make such a decision on her marriage? “Trust me, you’ll read this book again when you’re forty, and you’ll say, ‘Oh, I see!’” our professor said.②Yet there’s a theory behind the assignment of “Middlemarch”: knowledge acquired too early gets stored away. Patterns of thinking established now will be retraced later; ideas encountered first in art will prepare us for the rest of life. This sounds unclear, until you reflect on the fact that you take a class in law school today only to argue a complicated case years later. Knowledge must often molder in our mental warehouses for decades until we figure out what to do with it.③Leslie Valiant, a distinguished computer scientist, calls our ability to learn over the long term “educability”.In his new book, “The Importance of Being Educable,” he argues that it’s key to our success.When we think about what makes our minds special, we tend to focus on intelligence. But if we want to grasp reality in all its complexity, Valiant writes, then “cleverness is not enough.” We need to build comprehensive and flexible theories about the world —theories that will serve us in new, unanticipated, and strange circumstances —and we do that by gathering diverse kinds of knowledge, often in a slow, additive, accidental way, and knitting them together. Through this process, we acquire systems of beliefs that are broader and richer than the ones we can create through direct personal experience.④An educable mind, he writes, can learn from books, lectures, conversations, experiences, —from anything, really —and notice when relevant aspects of almost forgotten knowledge reveal themselves. We admire aspects of someone’s educability when we say that they are a quick study, but what really makes them educable is that they apply insights “for purposes not foreseen at the time of the study”. When people strike us as particularly well- educated, this might mean that they have had lots of school, but it could also mean that they’re exceptionally educable, with the ability to take good advantage of whatever educational opportunities arise,whether formal or informal.⑤Valiant thinks it might be useful to promote educability as an ideal. We could try to figure out how to measure and teach it in schools, or to encourage it in adults; at a time when rapid technological change means there’s always more to learn, we might seek to create a more educable society in general.43.The underlined word “molder” (paragraph 2) is closest in meaning to “”.A.become out-of-dateB. keep practicalC. remain inactiveD. stay safe44.Which of the following mind map correctly illustrate the relationship among knowledge, theory and beliefs?A. B.C. D.45.What can be inferred from paragraph 4?A.True educability lies in presenting insights for unforeseen purposes.B.A quick learner overestimates the value of learning from all sources.C.Schooling ensures that an educable mind can seize all learning opportunities.D.An educable mind pursues learning even without an immediate goal in mind.46.The passage is intended to .A.introduce a book on educabilityB.maximize the benefits of educabilityC.inspire people to create an educable societyD.recommend a distinguished computer scientistSection CDirections: Read the following passage. Fill in each blank with a proper sentence given in the box. Each sentence can be used only once. Note that there are two more sentences than you need.A.What happens if you lose cell-phone service?B.The point is to be able to see the views and smell the flowers.C.But the most essential equipment is footwear because your feet are literally your foundation.D.Spending time in nature and having experiences that inspire amazement can lower stress and anxiety.E.If the idea of breaking a sweat on the tracks sounds appealing but you’re not sure how to start, we’ve gotyou covered.F.It can be as simple as heading out the door and walking for 40 minutes to an hour to build up strength andendurance.Hiking: How to Get StartedHiking, a form of exercise older than exercise itself, is so hot right now. For dedicated hikers, hiking offersfreedom and perspective. But for those of us who haven’t spent serious time outdoors since summer camp, a half- day hike can be difficult. How can you avoid getting lost or injured? Do you really need special hiking shoes?47If you’re relatively active, you’re probably already training just by going for walks. 48To train for sharper land, walk up hills or take the stairs instead of a lift.The key to a relaxing hike is being as prepared as possible for the unknown, whether it’s a sudden downpour or an injured ankle. Every hiker should bring the 10 essentials, which include food and drink, first aid supplies, a map and compass and rainwear. 49 You don’t need to invest in special hiking shoes. You do need to wear shoes that offer firmness and protection, especially if the track is rocky, sharp or potentially muddy.Finally, to avoid injury, don’t push yourself too hard or fast through more challenging tracks. Remember:50 Slow down, take in the scenery, listen to the birds, and just be present in nature.Ⅲ. Summary WritingDirections: Read the following passage. Summarize the main idea and the main point(s) of the passage in no more than 60 words. Use your own words as far as possible.How to Make a Good Video Resumé(简历)?Video resumés have been around for a long time. With a well-made video resumé, you can present yourself creatively and allow a hiring manager to assess your personality, thus giving you an opportunity for interview. But how to make a good video resumé?First, start by introducing yourself and addressing the company you are applying to. For example, “Hello InVideo, I’m John Doe”. Not only does this get their attention but it makes them feel prioritized. The next thing is to address what profession you’re in or desire to be in. If you’re a filmmaker, you can simply state that or be creative with words and say you’re a visual storyte ller.Then, talk about your passion for what you do and support it by referring to your past experiences and work. For example, building on the filmmaker’s introduction, you could talk about how meeting people from around the world and sharing their stories deeply motivates you, and then you can share an experience that supports it.You can also focus on life experiences that have led you to cultivate skills - like taking a year off to travel abroad, volunteering at a shelter, or a hobby that you actively pursue. You can also speak about your special achievements and awards that will add value to your profile or you can get someone to speak on behalf of you as social proof.At the end of the video, leave the ball in their court. However, you also need to give them a reason to call you for an interview. For example, you could end the video with this - “I have a lot more to me than I could fit in this short video and I hope you give me a chance to tell you about it over an interview”.第II卷（共40分）Ⅳ. TranslationDirections: Translate the following sentences into English, using the words given in the brackets.52.这款饮料由水果和蔬菜汁混合而成，味道很好。

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JannickP.RollandSchoolofOptics/CREOL,andSchoolofElectricalEngineeringandComputerScienceUniversityofCentralFloridaOrlando,FL32816–2700

HenryFuchsDepartmentofComputerScienceUniversityofNorthCarolinaChapelHill,NC27599-3175

OpticalVersusVideoSee-ThroughHead-MountedDisplaysinMedicalVisualization

AbstractWecomparetwotechnologicalapproachestoaugmentedrealityfor3-Dmedicalvisualization:opticalandvideosee-throughdevices.Weprovideacontexttodiscussthetechnologybyreviewingseveralmedicalapplicationsofaugmented-realityre-searcheffortsdrivenbyrealneedsinthemedical󰀷eld,bothintheUnitedStatesandinEurope.Wethendiscusstheissuesforeachapproach,opticalversusvideo,frombothatechnologyandhuman-factorpointofview.Finally,wepointtopotentiallypromisingfuturedevelopmentsofsuchdevicesincludingeyetrackingandmultifocusplanescapabilities,aswellashybridoptical/videotechnology.

1IntroductionOneofthemostpromisingandchallengingfutureusesofhead-mounteddisplays(HMDs)isinapplicationsinwhichvirtualenvironmentsenhanceratherthanreplacerealenvironments.Thisisreferredtoasaugmentedreality(Bajura,Fuchs,&Ohbuchi,1992).Toobtainanenhancedviewoftherealen-vironment,userswearsee-throughHMDstosee3-Dcomputer-generatedob-jectssuperimposedontheirreal-worldview.Thissee-throughcapabilitycanbeaccomplishedusingeitheranopticalHMD,asshowninfigure1,oravideosee-throughHMD,asshowninfigure2.Weshalldiscussthetradeoffsbetweenopticalandvideosee-throughHMDswithrespecttotechnologicalandhu-man-factorissues,anddiscussourexperiencedesigning,building,andtestingtheseHMDsinmedicalvisualization.Withopticalsee-throughHMDs,therealworldisseenthroughhalf-trans-parentmirrorsplacedinfrontoftheuser’seyes,asshowninfigure1.Thesemirrorsarealsousedtoreflectthecomputer-generatedimagesintotheuser’seyes,therebyopticallycombiningthereal-andvirtual-worldviews.Withavideosee-throughHMD,thereal-worldviewiscapturedwithtwominiaturevideocamerasmountedontheheadgear,asshowninfigure2,andthecom-puter-generatedimagesareelectronicallycombinedwiththevideorepresenta-tionoftherealworld(Edwards,Rolland,&Keller,1993;Stateetal.,1994).See-throughHMDswerefirstdevelopedinthe1960s.IvanSutherland’s1965and1968opticalsee-throughandstereoHMDswerethefirstcomputergraphics-basedHMDsthatusedminiatureCRTsfordisplaydevices,ame-chanicaltrackertoprovideheadpositionandorientationinrealtime,andahand-trackingdevice(Sutherland,1965,1968).Whilemostofthedevelop-mentsinsee-throughHMDsaimedatmilitaryapplications(Buchroeder,Presence,Vol.9,No.3,June2000,287–309

r2000bytheMassachusettsInstituteofTechnology

RollandandFuchs287Seeley,&Vukobratovich,1981;Furness,1986;Droessler&Rotier,1990;Barrette,1992;Kandebo,1988;Desplat,1997),developmentsin3-Dscientificandmedicalvisualizationwereinitiatedinthe1980sattheUniversityofNorthCarolinaatChapelHill(Brooks,1992).Inthispaper,weshallfirstreviewseveralmedicalvisu-alizationapplicationsdevelopedusingopticalandvideosee-throughtechnologies.Weshallthendiscusstechno-logicalandhuman-factorsandperceptualissuesrelatedtosee-throughdevices,someofwhichareemployedinthevariousapplicationssurveyed.Finally,weshalldis-cusswhatthetechnologymayevolvetobecome.2SomePastandCurrentApplicationsofOpticalandVideoSee-ThroughHMDsTheneedforaccuratevisualizationanddiagnosisinhealthcareiscrucial.Oneofthemaindevelopmentsofmedicalcarehasbeenimaging.SincethediscoveryofX-raysin1895byWilhelmRoentgen,andthefirstX-rayclinicalapplicationayearlaterbytwoBirmingham(UK)doctors,X-rayimagingandothermedicalimagingmo-dalities(suchasCT,ultrasound,andNMR)haveemerged.Medicalimagingallowsdoctorstoviewas-pectsoftheinteriorarchitectureoflivingbeingsthatwereunseenbefore.Withtheadventofimagingtech-nologies,opportunitiesforminimallyinvasivesurgicalprocedureshavearisen.Imagingandvisualizationcanbeusedtoguideneedlebiopsy,laparoscopic,endoscopic,andcatheterprocedures.Suchproceduresdorequireadditionaltrainingbecausethephysicianscannotseethenaturalstructuresthatarevisibleinopensurgery.Forexample,thenaturaleye-handcoordinationisnotavail-ableduringlaparoscopicsurgery.Visualizationtech-niquesassociatedwithsee-throughHMDspromisetohelprestoresomeofthelostbenefitsofopensurgery(forexample,byprojectingavirtualimagedirectlyonthepatient,eliminatingtheneedforaremotemonitor).Thefollowingparagraphsbrieflydiscussexamplesofrecentandcurrentresearchconductedwithopticalsee-throughHMDsattheUniversityofNorthCarolinaatChapelHill(UNC-CH),theUniversityofCentralFlorida(UCF),andtheUnitedMedicalandDentalSchoolsofGuy’sandSaintThomas’sHospitalsinEn-gland,video-see-throughatUNC-CH,andhybridopti-cal-videosee-throughattheUniversityofBlaisePascalinFrance.Arigorouserror-analysisforanopticalsee-throughHMDtargetedtowardtheapplicationofopticalsee-throughHMDtocraniofacialreconstructionwascon-ductedatUNC-CH(Holloway,1995).Thesuperimpo-sitionofCTskulldataontotheheadoftherealpatientwouldgivethesurgeons‘‘X-rayvision.’’Thepremiseof