光电信息工程外文翻译文献
电子信息工程 外文翻译 外文文献 英文文献 文献翻译
Technology and Application of Fieldbus Control System ---------IntelligentEquipment & Measurement And Control System Based on DeviceNetPromoted by the new technological revolution that automation control technology is tending digitization and internet in the field of automation industry, Shanghai Aton Electric Co., Ltd. developed Intelligent Equipment & Measurement And Control System Based on DeviceNet as a high and new technology industrialization model project. It was a state hi-tech development project of 2000 and was approved by the State Committee of Technology. Shanghai Aton Electric Co., Ltd. constructed production line of intelligent controller of pump and valve, relying on Shanghai Electric (Group) Corporation; constructed measurement and control system FCS R&D center of intelligent controller of pump and valve and built up mass production R&D basis, cooperating with Shanghai Jiaotong University and Shanghai University; constructed FCS remote diagnosis and service center of intelligent controller of pump and valve; constructed FCS training center of intelligent controller of pump and valve; founded mass production R&D basis along with the Rockwell Laboratory of Shanghai Jiaotong University and CIMS Center.1 Summary(1)Fieldbus control system is a system applied to field of production and microcomputerized measurement control equipment to realize both-way multinode serial communications. It is also called low-level control network for open, digital and multiplespot communications.Application: Flow Control System of Manufacturing; Process Control System; Traffic Control & Management; Building Automation. Features: Fieldbus control system is low-level low-bandwidth digital communication and control network in industrial system as well as open system connecting microcomputerized appearance. Intelligent instrument and controller are equal to microcomputer. They make up network with Fieldbus control system as the links to complete digital communication and other tasks.(2)Difference between FCS and DCS,FCS is updated control system after DCS integrated with digital control system and distributing control system. It solves the problem that in traditional DCS, devices made by different manufacturers cannot be connected. They can't realize exchange and operation to organize an network system with wider range of information sharing. It conquers the defect that special closed system for network should be used for communication in DCS to realize various functions of integrated automation. It turns the distributing structure combiningconcentration with deconcentration in DCS into new-type full distributing structure. It releases the control function to the field thoroughly and makes it possible to realize basic control function by means of fieldbus equipment itself. FCS breaks the traditional structure form of control system. The traditional analog control system adopts one-to-one equipment tie-wire and puts up connections respectively according to control loop. FCS adopts intelligent field equipment to place the control module, all input/output modules that used to be in the control chamber of DCS into field equipment. Since field equipment has ability to communicate, the field measuring and transferring instruments can transfer signals to actuating mechanism such as valve directly. Its control function can be fulfilled directly on the spot independent of the computer or control meter in the control chamber, which realizes thorough decentralized control.FCS adopts digital signals to replace analog signals so that multiple signals (including multiple operating parameter values, device status and failure information) can be transferred on a pair of cables. Meanwhile, it can give power supply to several devices. No switched block for analog/digital or digital/analog is needed besides fieldbus.(3)Characteristics of FCS●Open System;●Interoperability;● replace ability of devices made by different manufacturers.● Intelligentize and Autonomy;●Field equipment completing basic functions of automatic control.●Decentralized System Structure;●Field Adaptability;●Relatively Strong Interference Killing Feature and Safety●Intelligentized local equipment can save investment and quantity of hardware●Saving installation expenses and cables●Saving daily maintenance expenses●Enhancing accuracy and reliability of system●Enhancing initiativeness of system integration for users(4)Development Background and Trend of Fieldbus Control System,With the rapid development of computer and computer network, FCS has been rapidly developed as the interlinked communication network between the field intelligentdevices in the field of process automation, building and traffic etc. Because FCS meets the needs that industrial control system is developing in the way of decentralization, network and intellectualized, it has become the focus of global industrial automation and been universally concerned by the whole world. FCS has caused great revolutions on the aspects of system structure and function system for the current production of automation instrument, distributing control system and programmable controller. It is predicted that FCS will be the general trends in a very long time in the future fore sure.2 APPLICATION OF RELAYThe product reliability generally refers to the operating reliability. It is defined as: the ability of accomplishing the specified function under prescribed conditions and in prescribed time. It consists of intrinsic reliability and application reliability. The intrinsic reliability is determined by product designing and manufacturing technique, and the application reliability is concerned with the correct application of users and the services provided by the manufacturer before and after selling. When using relay, the user should pay attention to the following items.2.1 Coil applied voltageIt is best to choose the coil applicative voltage according to the rated voltage in design, or choose the voltage according to the temperature rising curve. Using any coil voltage that is less than the rated voltage will affect the operation of the relay. The coil operating voltage refers to the voltage that is applied between the coil terminals. The voltage value between the two terminals must be guaranteed, especially when using enlargement circuit to energize the coil. Whereas, it will also affect the relay characteristics if the applied voltage exceeds the highest rated voltage. Exorbitant voltage will bring exorbitant coil temperature rising, especially in high temperature ambient. Exorbitant temperature rising will damage the insulating material and affect the working safety of relay. For magnetic latching relay, energizing (or return) pulse width should not less than 3 times of the operating (or return) time, otherwise, the relay would be left on the middle-position state. When using solid-state components to energize the coil, the components dielectric strength must be above 80V, and the leakage of current must be as little as possible to ensure the relay to release.Energizing power source: Under 110% of the rated current, the adjusting ratio of the power source is less than 10% (or the output impedance is less than 5% of the coilimpedance), the wave voltage of the DC power source is less than 5%. The AC wave is sine wave; the waviness coefficient is between 0.95~1.25; wave distortion is within ±10%; the frequency change is within±1Hz or ±1% of the specified frequency (choosing the bigger value). The output power should not less than coil power consumption.2.2 Transient suppressionAt the moment when the coil power is stopped, peak-inverse voltage that is more than 30 times of the coil rated voltage is produced on the coil, which is harmful to the electronic circuit. Generally, the peak-inverse voltage is suppressed by transient suppression（cutting-peak）diode or resistance to limit the peak-inverse voltage within 50V. But the diode in parallel connection will delay3~5 times of the release time. If the request of the release time is high, a suitable resistance in series can be putted with and at one end of the diode.The power supply to relays in parallel connection and series connection,When several relays in parallel connection are supplied, the relay that the peak-inverse voltage is higher will release power to the relays that the peak-inverse voltage is lower. The release time of the relay will delay. So the relays in parallel connection should be controlled separately to eliminate mutual influence.The relays with different coil resistance and power can’t be used in series, otherwise, t he relay that the coil current is higher in the series circuit can’t operate reliably. Only the relays of the same specification can be used in series, but the peak-inverse voltage will be increased and the peak-inverse voltage should be suppressed. Resistance in series can be used to bear the part voltage that exceeds the rated voltage of the coil according to the ratio of the divided voltage.2.2.1 Contact loadThe load applied to the contacts should be accordant to the rated load and characteristics of the contacts. A load that is not applied according to the rated value range will cause problem. The relay that is only suitable for DC load can’t be used in AC occasions. The relay that can switch 10A load can’t always reliably operate in low level load (less than 10m A×6A) or in dry circuit occasions. The relay that can switch single-phase AC power source isn’t always suitable to switch two single-phase AC loads that aren’t synchronous; the relay that is only specif ied to switch the load of AC 50Hz（or 60Hz）can’t be used to switch AC load of 400Hz.2.2.2 Parallel and series connection of contactsThe contacts used in parallel connection can’t increase the load current, because the operating times of several sets of contacts are absolutely different; that is to say, there is still only a set of contacts switching the increased load. This would damage or weld the contacts and make the contacts can’t close or open. The parallel connection of the contacts can decrease t he misplay of “break”. But the parallel connection of the contacts would increase the misplay of “freezing”. Because the misplay of “break” is the main pattern of invalidation of contacts, the parallel connection can increase the reliability and can be used on the pivotal part of equipments. But the applied voltage should not exceed the highest operating voltage of the coil and should not less than 90% of the rated voltage, otherwise, the coil life and the applicative reliability would be damaged. The series connection of the contacts can increase the load voltage. The amount of the contact sets is equal to the times that the load voltage can be increased. The series connection of contacts can decrease the misplay of “freezing”, but it would increase the mis play of “break”. Anyway, when using redundant technology to increase the operating reliability of contacts, the characteristics and size and the failure mode of load must be considered.2.2.3 Switching speedThe switching speed should not exceed the reciprocal of 10 times of the sum of operating and release time (times/s), otherwise, the contacts can’t switch on steadily. Magnetic latching should be used under the pulse width specified in the technique criterion, or the coil may be damaged.3 RVT DISTRIBUTING ELECTRICITY INTEGRATE TESTAPPARATUSBasic functionMeasure asupervision:Three mutually electric voltage/electric current/ power factor with a great achievement/ power without a great achievement/electricity with a great achiverment/electricity/homophonic-wave electric voltage/ homophonic-wave electric/ current Day electric voltage/ electric current biggest and minimum value/fire for the failure Electric voltage over top, the limit/ lack mutually of time homophonic-wave analyzes is up to 13 times.The data is stored for 2 months.The data communicateRS232/485 communicating connect，The way in communicating can adopt the spot communicating or the long range communicating.，Possible to settle invoke orthe solid hour invokes, responding to the modification and long ranges control of the parameter.Without power compensationTaking physics measures as the power factor without a great achievement,the power factor with a great achievement and the dull place without power compensation;Y+ the combination method of the △，Y+ the △connects the line method，Y+ △ , Y, the △ connects the line method.Data managementAccording to WINDOW98 operation terrace, data in communication automatically reports born statement, curve and pillar form diagrams.Circulation of the protectionWhen the charged barbed wire net of mutually electric voltage over press, owe to press, and a super limit hour fast cut off in expiation of capacitor，When the charged barbed wire net lacks mutually or super limit in the preface of zero hour fast cut off in expiation of capacitor.screen manifestationChinese operation interface，Adopt 128*64 the back light liquid crystal display.The solid hour shows the charged barbed wire net relevant parameter.view manifestation to place the parameter.现场总线控制系统的技术和应用随着新的科学技术革命的出现，在自动化工业领域中，自动控制技术的发展趋向于数字化和网络互联化。
光信息科学与技术专业中英文对照外文翻译文献
中英文对照外文翻译文献中英文资料对照外文翻译原文1.5 Experimental SetupDue to the many concepts and variations involved in performing the experiments in this project and also because of their introductory nature, Project 1 will very likely be the most time consuming project in this kit. This project may require as much as 9 hours to complete. We recommend that you perform the experiments in two or more laboratory sessions. For example, power and astigmatic distance characteristics may be examined in the first session and the last two experiments (frequency and amplitude characteristics) may be performed in the second session.A Note of CautionAll of the above comments refer to single-mode operation of the laser which is a very fragile device with respect to reflections and operating point. One must ensure that before performing measurements the laser is indeed operating single-mode. This can be realized if a single, broad fringe pattern is obtained or equivalently a good sinusoidal output is obtained from the Michelson interferometer as the path imbalance is scanned. If this is not the case, the laser is probably operating multimode and its current should be adjusted. If single-mode operation cannot be achieved by adjusting the current, then reflections may be driving the laser multimode, in which case the setup should be adjusted to minimize reflections. If still not operating single-mode, the laser diode may have been damaged and may need to be replaced.WarningThe lasers provided in this project kit emit invisible radiation that can damage the human eye. It is essential that you avoid direct eye exposure to the laser beam. We recommend the use of protective eyewear designed for use at the laser wavelength of 780 nm.Read the Safety sections in the Laser Diode Driver Operating Manual and in thelaser diode section of Component Handling and Assembly (Appendix A) before proceeding.1.5.1 Semiconductor Diode Laser Power Characteristics1.Assemble the laser mount assembly (LMA-I) and connect the laser to its power supply. We will first collimate the light beam. Connect the laser beam to a video monitor and image the laser beam on a white sheet of paper held about two to ten centimeters from the laser assembly. Slowly increase the drive current to the laser and observe the spot on the white card. The threshold drive current rating of the laser is supplied with each laser. Increase the current to about 10-20 mA over the threshold value.With the infrared imager or infrared sensor card, observe the spot on the card and adjust the collimator lens position in the laser assembly LMA-I to obtain a bright spot on the card. Move the card to about 30 to 60 centimeters from the lens and adjust the lens position relative to the laser to obtain a spot where size does not vary strongly with the position of the white card. When the spot size remains roughly constant as the card is moved closer or further from the laser, the output can be considered collimated. Alternatively, the laser beam may be collimated by focusing it at a distance as far away as possible. Protect fellow co-workers from accidental exposure to the laser beam.2.Place an 818-SL detector on a post mount (assembly M818) and adjust its position so that its active area is in the center of the beam. There should be adequate optical power falling on the detector to get a strong signal. Connect the photodetector to the power meter (815). Reduce the background lighting (room lights) so that the signal being detected is only from the laser. Reduce the drive current to a few milliamperes below threshold and, again, check to see that room light is not the dominant signal at the detector by blocking the laser light.3. Increase the current and record the output of the detector as a function of laser drive current. You should obtain a curve similar to Figure 1.2. If desired, the diode temperature may also be varied to observe the effects of temperature on threshold current. When examining laser diode temperature characteristics, the laser diode driver should be operated in the constant current mode as a safeguard against excessive currents that damage the diode laser. Note that as the diode temperature is reduced, the threshold decreases. Start all measurements with the diode current off to prevent damage to the laser by preventing drive currents too high above threshold. To prevent destruction of the laser, do not exceed the stated maximum drive current ofthe laser.1.5.2 Astigmatic Distance CharacteristicsThe laser diode astigmatic distance is determined as follows. A lens is used to focus the laser beam at a convenient distance. A razor blade is, then, incrementally moved across the beam to obtain data for total optical power passing the razor edge vs. the razor blade position. A plot of this data produces an integrated power profile of the laser beam (Figure 1.9a) which through differentiation exposes the actual power profile (Figure 1.9b) which, in turn, permits determination of the beam diameter (W).A beam diameter profile is obtained by measuring the beam diameter while varying the laser position. Figure 1.9c illustrates the two beam diameter profiles of interest: one for razor edge travel in the direction perpendicular to the laser diode junction plane and the other for travel in the direction parallel to the junction plane. The astigmatic distance for a laser diode is the displacement between the minima of these two profiles. This method is known as the knife edge technique.1. Assemble the components shown in Figure 1.8 with the collimator lens (LC), in the rotational stage assembly (RSA-I), placed roughly 1 centimeter away from the laser. The beam should travel along the optic axis of the lens. This is the same lens used in collimating the laser in the previous setup. The approximate placement of all thecomponents are shown in the figure. Make sure that the plane of the diode junction (xz plane in Figure 1.1) is parallel with the table surface.2. Due to the asymmetric divergence of the light, the cross-section of the beam leaving the laser and, further, past the spherical lens is elliptical. The beam, thus, has two distinct focal points, one in the plane parallel and the other in the plane perpendicular to the laser diode junction. There is a point between the two focal points where the beam cross-section is circular. With the infrared imager and a white card, roughly determine the position where the beam cross-section is circular.Figure 1.9 – Procedure for finding astigmatic distance.3. Adjust the laser diode to lens distance such that the razor blades are located in the xy plane where the beam cross-section is circular.4. Move the laser diode away from the lens until minimum beam waist is reached at the plane of razor blades. Now, move the laser diode about 200 µm further away from the lens.5. Move razor blad e 1 in the x direction across the beam through the beam spread θx and record the x position and detected intensity at each increment (≤100 µm increments). The expected output is shown in Figure 1.9. The derivative of this curve yields the intensity profile of the beam in the x direction from which the beamdiameter is determined.6. Repeat with razor blade 2 for θy in the y direction.7. Move the laser closer to the lens in increments (≤50 µm) through a total of at least than 500µm. Repeat Steps 5 and 6 at each z increment, recording the z position.8. Using the collected data, determine the beam intensity profiles in the x and y directions as a function of the lens position z. This is done by differentiating each data set with respect to position. Then, calculate the beam diameter and plot as a function of z. The difference in z for the minimum in θx and θy is the astigmatic distance of the laser diode. Use of computer software, especially in differentiating the data, is highly recommended.If the laser junction is not parallel to the table surface, then for each measurement above, you will obtain an admixture of the two beam divergences and the measurement will become imprecise. If the laser is oriented at 45° to the surface of the table, the astigmatic distance will be zero.Different laser structures will have different angular beam divergences and, thus, different astigmatic distances. If you have access to several different laser types (gain guided, index guided), it may be instructive to characterize their astigmatic distances.1.5.3 Frequency Characteristics of Diode LasersIn order to study frequency characteristics of a diode laser, we will employ a Michelson interferometer to convert frequency variations into intensity variations. An experimental setup for examining frequency and, also, amplitude characteristics of a laser source is illustrated in Figure 1.10.1. In this experiment, it is very possible that light may be coupled back into the laser, thereby, destabilizing it. An optical isolator, therefore, will be required to minimize feedback into the laser. A simple isolator will be constructed using a polarizing beam splitter cube and a quarterwave plate. We orient the quarterwave plate such that the linearly polarized light from the polarizer is incident at 45° to the principal axes of the quarterwave plate so that light emerging from the quarterwave plate is circularly polarized. Reflections change left-circular polarized light into right-circular or vice versa so that reflected light returning through the quarterwave plate will be linearly polarized and 90° rotated with respect to the polarizer transmission axis. The polarizer, then, greatly attenuates the return beam.In assembling the isolator, make sure that the laser junction (xz plane in Figure 1.1) is parallel to the surface of the table (the notch on the laser diode case points upward) and the beam is collimated by the lens. The laser beam should be parallel tothe surface of the optical table. Set the polarizer and quarterwave (λ/4) plate in place. Place a mirror after the λ/4 plate and rotate the λ/4 plate so that maximum rejected signal is obtained from the rejection port of the polarizing beam splitter cube as shown in Figure 1.11. When this signal is maximized, the feedback to the laser should be at a minimum.2. Construct the Michelson interferometer as shown in Figure 1.12. Place the beam steering assembly (BSA-II) on the optical table and use the reflected beam from the mirror to adjust the quarterwave plate orientation. Set the cube mount (CM) on the optical breadboard, place a double sided piece of adhesive tape on the mount, and put the nonpolarizing beam splitter cube (05BC16NP.6) on the adhesive tape. Next, place the other beam steering assembly (BSA-I) and the detector mount (M818BB) in location and adjust the mirrors so that the beams reflected from the two mirrors overlap at the detector.When long path length measurements are made, the interferometer signal will decrease or disappear if the laser coherence length is less than the two way interferometer path imbalance. If this is the case, shorten the interferometer until the signal reappears. If this does not work, then check the laser for single-mode operation by looking for the fringe pattern on a card or by scanning the piezoelectric transducer block (PZB)in BSA-II and monitoring the detector output which should be sinusoidal with PZB scan distance. If the laser does not appear to be operating single-mode, realign the isolator and/or change the laser operating point by varying the bias current. Additionally, to ensure single-mode operation, the laser should be DC biased above threshold before applying AC modulation. Overdriving the laser can also force it into multimode operation.3. The Michelson interferometer has the property that depending on the position of the mirrors, light may strongly couple back toward the laser input port. In order to further reduce the feed-back, slightly tilt the mirrors as illustrated in Figure 1.13. If still unable to obtain single-mode operation, replace the laser diode.4. Place a white card in front of the detector and observe the fringe pattern with the infrared imager. Slightly adjust the mirrors to obtain the best fringe pattern. Try to obtain one broad fringe.5. Position the detector at the center of the fringe pattern so that it intercepts no more than a portion of the centered peak.6. By applying a voltage to the piezoelectric transducer block attached to the mirror (part PZB) in one arm of the interferometer (i.e. BSA-II), maximize the output intensity. The output should be stable over a time period of a minute or so. If it is not, verify that all components are rigidly mounted. If they are, then room air currents may be destabilizing the setup. In this case, place a box (cardboard will do) over the setup to prevent air currents from disturbing the interferometer setup.7.Place the interferometer in quadrature (point of maximum sensitivity between maximum and minimum outputs of the interferometer) by varying the voltage on the PZB.8. The output signal of the interferometer due to frequency shifting of the laser is given by ∆I∝∆φ = 2π/c ∆L ∆ν where ∆L is the difference in path length between the two arms of the interferometer and ∆ν is the frequency sweep of the laser that is induced by applying a current modulation. Remember that in a Michelson interferometer ∆L is twice the physical difference in length between the arms since light traverses this length difference in both directions. ∆L values of 3-20 cm represent convenient le ngth differences with the larger ∆L yielding higher output signals.Before we apply a current modulation to the laser, note that the interferometer output signal, ∆I, should be made larger than the detector or laser noise levels by proper choice of ∆L and current modulation amplitude di. Also recall from Section 1.3that when the diode current is modulated so is the laser intensity as well as its frequency. We can measure the laser intensity modulation by blocking one arm of the interferometer. This eliminates interference and enables measurement of the intensity modulation depth. We, then, subtract this value from the total interferometer output to determine the true dI/di due to frequency modulation. Apply a low frequency, small current modulation to the laser diode. Note that when the proper range is being observed15mA 10didv v 1--= and1mA 2.0didI I 1-= for the amplitude change only.Recallingi v L c 2di d di dI ∆∆∆=∆∝πφ）（ ,15mA 10~didI Lv 2c --∆π, or15-mA 10L K 2~di dI -∆λπ where K is a detecto r response constant determined by varying ∆L.9. With the interferometer and detection system properly adjusted, vary the drive frequency of the laser and obtain the frequency response of the laser (Figure 1.4 or1.10a).You will need to record two sets of data: (i) the modulation depth of the interferometer output as a function of frequency, and (ii) the laser intensity modulation depth. The difference of the two sets of collected data will provide an estimate of the actual dI/di due to frequency modulation. Also note that if the current modulation is sufficiently small and the path mismatch sufficiently large, the laser intensity modulation may be negligible. You may need to actively keep theinterferometer in quadrature by adjusting the PZB voltage.Make any necessary function generator amplitude adjustments to keep the current modulation depth of the laser constant as you vary the frequency. This is because the function generator/driver combination may not have a flat frequency response. The effect of this is that the current modulation depth di is not constant and varies with frequency. So to avoid unnecessary calculations, monitor the current modulation depth by connecting the LASER MONITOR connector on the laser diode driver system to an oscilloscope and keep the modulation depth constant by adjusting the amplitude of the applied sinusoidal wave as a function of frequency. Record the frequency for your laser at which the thermal contribution to dν/di begins to become negligible and dν/di drops off (see Section 1.3).10. Keeping the above equations in mind, we will, now, measure the FM chirp characteristics of the laser. At a constant current modulation frequency (choose a modulation frequency where dν/di varies rapidly, i.e. where the slope of your grap h from Step 9, which should be similar to Figure 1.10a, is maximum), vary the current modulation depth di for different laser bias levels and derive a curve such as the one in Figure1.10b.The output dν should not vary significantly except around threshold and at high currents.CautionDo not exceed the specified drive currents/output power ratings of the diode or it may be damaged.11. The phase noise characteristic behavior (Section1.4) as a function of interferometer path length imbalance ∆L may be determ ined by inducing phase noise through application of laser current modulation. Make sure that the interferometer is in quadrature.Set the laser diode current above threshold, apply a small current modulation, and fix the modulation frequency at a desired value. Convenient frequencies may include 50 Hz, 2 kHz, and 50 kHz (see Reference 1.5). Monitor the detector output with a spectrum analyzer or an oscilloscope and record the peak-to-peak output intensity at interferometer quadrature. You may accomplish this by manually sweeping the PZB voltage to cause a minimum of π/2 phase shift, recording the maximum peak-to-peak intensity as a function of path length imbalance. It is important to ensure that instrument noise is below the signal levels expected and it is assumed that single-mode operation of the laser is maintained. Curves similar to Figure 1.10c should be obtained.1.5.4 Amplitude Characteristics of Diode LasersThe measurements of the intensity characteristics are taken by placing the detector before the interferometer as in Figure 1.10 or by blocking one mirror in the interferometer. Again, the laser must be operated single-moded with minimum feedback or the noise level and functionality will drastically change. The relative intensity noise (RIN) is defined as 20log(dI/I) where dI is the RMS intensity fluctuations so that for dI~10-4 , the RIN is -80 dB. Normally, these measurements are made with a spectrum analyzer and a 1 Hz bandwidth.When making RIN measurements, electronic and photodetector shot noise must be below the RIN levels. (OPTIONAL) You may determine the shot noise using an incoherent source (e.g. lamp) with an intensity level similar to that of the laser. The resultant frequency spectrum of noise with the light source excited gives a measure of the shot noise level which should be adjusted to be at least 10 dB greater than electronic noise levels. The measured shot noise should be checked with Equation0.47.1. Vary the laser drive current from below threshold through and above the threshold and record the laser output power and intensity noise at a desired frequency using a spectrum analyzer. When you calculate the RIN, assuming that shot and electronic noises are below the RIN level, a plot similar to that presented in Figure 1.10d should be obtained. In most cases, for single-mode operation, the noise peaks at threshold. The shape of the noise curve may vary if the laser is modulated, if it becomes multi-modal, or if the side-mode suppression on a nominally single-mode laser is not adequate (< 20 dB).2. It is instructive to operate the laser with modulation signals of varying depth and/or degrading the isolator performance by rotating the λ/4 plate to increase feedback to the laser. This will illustrate noise properties for various feedback conditions which are important to subsequent sensor and communication experiments. RINs of less than -150dB and -120dB are required for television broadcast signals and sensitive interferometric sensors, respectively.3. The intensity noise of diode lasers has a 1/f characteristic (performance is degraded as the frequency is lowered). With the laser above threshold and the photodetector connected to a spectrum analyzer, determine the RIN as a function of modulation frequency. The response shown in Figure 1.10e should be obtained where the noise becomes white (flat with frequency) starting somewhere between 100 kHz and 1 MHz for typical lasers.NOTE: The Michelson interferometer setup used in this project will again be used in Project3. It may, therefore, save time to proceed directly to Project3 before completing characterization of diode lasers in Project2.中文翻译1.5 实验装置由于在这个项目中执行这个实验时涉及到许多新的概念和变化，也因为它们是初始性的工作，项目1可能是这个实验单元中最耗时的项目。
电子信息工程专业毕业论文中英文资料外文翻译文献
毕业论文毕业论文中英文对照翻译中英文对照翻译院（系部） 电气工程与自动化 专业名称 电子信息工程Infrared Remote Control SystemAbstractRed outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique,drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point SSL, be free from electromagnetism thousand Raos etc.characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage.Along with red outside the data deliver a technique more and more mature, the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application.The purpose that design this system is transmit customer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplish customer’s operation demand.Keywords:Infrare dray；Code；Decoding；LM386；Redoutside transceiver1 Introduction1.1 research the background and significanceInfrared Data Communication Technology is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.Infrared transceiver products with low cost, small, fast transmission rate, the point-to-point transmission security, not subject to electromagnetic interference and other characteristics that can be achieved between the different products, rapid, convenient and safe exchange and transmission, In short distance wireless transmission have a very distinct advantage.Infrared transceiver products in the portable product of a great role. At present, the world's 150 million piece of equipment used infrared technology in electronic products and industrial equipment. medical equipment and other fields widely used. For example, 95% of the notebook computers on the installation of infrared transceiver interface the majority of the cell phone is also the allocation of infrared transceiver interface. With the exchange of quantitative data, infrared data communications will enable cell phone data transmission more convenient. With infrared data transmission technology matures, perfect, low costs, Infrared Transceiver in short distance communications will be more widely applied.This chapter first describes the infrared transceiver IC design issues to the background and significance. then briefed the infrared data communications technology features and applications, and infrared transceiver product characteristics, domestic and international situation and development trend of the last under infrared remote transceiver system in practical application to establish a task of design orientation.1.2 Infrared Remote ControlTransceiver SystemInfrared remote control system is divided into single-channel and multi-channel remote control. Only a command signal transmission channel, called single-channel remote control system; with more than two instructions signal transmission channel known as a multi-channel remote control system. Relatively simple single-channel remote control, in general, only a launcher directive Key receivers and only one circuit implementation. While in the receiving circuit to add more stable memory circuits that can be activated commands to launch a number of key, so that the receiver circuit multistable memory circuit repeatedly to change the state, to realize many of the functional control, But such a state of change is the order. If we are to achieve an arbitrary control, resort to the use of multi-channel remote control system. Multi-channel remote control can be realized by the object of arbitrary multi-function remote control. As for the choice of several routes and what control methods, according to the actual situation (such as object, operational requirements and cost accounting, etc.) to decide. General infrared remote transceiver system by infrared remote control transmitter signal coding, infrared remote control signal receivers and decoders (or decoder chip MCU) and the external circuit consisting of three parts. Signal transmitter remote control code used to generate pulses of infrared emission-driven output infrared remote control signal, receiver completion of the remote control signal amplification and detection, plastic and demodulation encoding pulse. Infrared remote control coded pulse is going to obtain a continuous serial binary code, and for most of the infrared transceiver system, This serial code as micro-controller of the remote control input signals from the internal CPU completion of the remote control instruction decoder, on the other infrared remote control transceivers, the designers of electronic products, The internal micro-controller of the remote control decoder directive is not accessible.Therefore, people are using infrared encoder / decoder chip and microcontroller developed various generic infrared remote transceiver system, In various equipment infrared signals between the transceiver.Remote transceiver system generally transmitters and receivers is composed of two parts. Launchers from the general direction keys, coded instructions circuit modulation circuit, driving circuit, firing circuit of several parts. When pressed a key, the directive coding circuit, in the corresponding instructions encoded signal, the encoder signal to the carrier modulation, Driven by the power amplifier circuit after circuit fired from the field after firing instructions coded modulation signals. General receiver by the receiving circuit, the amplifier circuit, demodulation circuits, instruction decoder circuit, driving circuit, circuit implementation of several parts. Receiving Circuit will launch vehicles have been coded modulation signal receiving instructions from, and to enlarge evacuation demodulation circuit. Demodulation circuit will have the coding modulation signal demodulation, namely, reduction of signal coding. The instruction decoder to the encoder signal decoding, Driven by the final circuit to drive the implementation of various instructions circuit to control the operation.1.3 infrared remote control transceiver product profiles 1.3.1 infrared remote control transceiver product structure and typeCurrently infrared transceiver in accordance with the mode of transmission rate and can be divided into four categories : Serial mode, the highest rate of 115.2 Kbps; medium-speed model : the highest rate of 0.567 Mbps and 1.152Mbps; High-speed mode : The maximum rate of 16 Mbps.Also according to the size chip power consumption can be divided into low-power consumption and standard two categories, low-power type normally used 3 V power supply, transmission distance closer to about 0 - 30cm, which is commonly used standard 5V power supply, transmission distance away at least 1mabove.1.3.2 infrared remote control transmitters of the status quo at home and abroadInfrared communication technology in the development stage and there are several infrared communication standards, between different standards for infrared equipment can not infrared communication. To have all the infrared equipment to interoperability in 1993 by more than 20 large manufacturers initiated the establishment of an Infrared Data Association (IRDA) unified the infrared communication standards , which is currently widely used in infrared data communication protocols and standards, also known as the IRDA standard.Since 1993 IRDA since the establishment of the Infrared Data Association members have developed to more than 150. IRDA standards of the industry has been widely recognized and supported. Has been developed with the infrared communications equipment have been as many as 100 species. IR module, installed capacity has reached 150 million sets. Although there is also a short distance wireless Bluetooth technology, But in infrared communication technology low cost and broad compatibility advantages, Infrared data communication in the future will still be a very long time inherent short-range wireless data communications fields play an important role.1.3.3 Infrared Transceiver product development trendIn various infrared transceiver products, although the transmission rate, transmission distance and other characteristics, But infrared transceiver products has been towards improving the transmission rate, increase the transmission distance and lower power consumption, expanding launch reception angle of development. In particular, as the technology development and maturity, the means of transmission is moving in the direction of point-to-multipoint. Therefore infrared remote control transceiver products have broader prospects for development.2 Infrared communication of knowledge2.1 infrared ray foundation knowledge2.1.1 infrared outlinedInfrared is actually a kind of electromagnetic wave. From the analysis of various natural component of the electromagnetic wave reflected spectrum is :-ray, x-ray, ultraviolet, visible, infrared, microwave and radio wave. From the viewpoint of form, and they did not seem to, but if the wavelength in descending order, and we will find him all the only visible light spectrum of the entire 0.38 µm - 0.76µm so long little area, and adjacent to the visible light and infrared (including the far infrared, mid-infrared and near infrared foreign) accounts for the spectrum of 0.76 µm - 1000µm of a major. Which micron wavelength range also includes UV, visible, near infrared, mid-infrared and far-infrared, microwave.From the above analysis shows that infrared is a very rich spectrum resources, it currently has in production, life, military, medical, and other aspects have been widely used, such as infrared heating, medical infrared, infrared communication, infrared camera, infrared remote control, and so on. Infrared remote control is the many applications of infrared part of the current household appliances widely used in TV remote control, VCR remote control, VCD remote control, high-fidelity audio remote control, are used infra-red remote control, It allows the control of these appliances have become very easy.2.1.2 infrared propertiesInfrared lies between visible light and microwave a wave, it is with certain clinical characteristics of the wave. In the near-infrared, visible light and its adjacent, it is visible in certain characteristics, such as straight-line transmission, reflection, refraction, scattering, diffraction, can be certainobjects and can be absorbed through the lens of their focusing. In the far-infrared region, owing to its neighboring microwave, it has some characteristics of microwave, If a strong penetrating power and can run through some opaque substances. Since in any object, natural profession, regardless of whether its own luminescence (referring to visible light), as long as the temperature is above absolute zero (-273 ° C), moment will be kept around to infrared radiation. Only higher temperature of objects strong infrared radiation, low-temperature objects infrared radiation weaker. Therefore infrared feature is the greatest common in nature, it is called thermal radiation called thermal radiation. Infrared cameras, infrared night market pyroelectric infrared detectors and some other missiles aiming at is the use of this characteristic of infrared work.Infrared and visible light compared to another characteristic of a variety of colors. As the longest wavelength of visible light is a wavelength of the shortest times (780 nm-380 nm), So is called an octave. And infrared wavelength is the longest shortest wavelength of a times, and the longest wavelength infrared is the shortest wavelength of 10 times, that is, 10 octave. Therefore, if visible light can be expressed as seven colors, infrared may performance 70 colors, showing the rich colors. Infrared smoke through the good performance, which is also one of its features.Because not visible to the infrared, it has little effect on the environment. By the wave infrared rays than the long wavelength radio waves, infrared remote control will not affect the nearby radio equipment. Another wavelength of less than 1.5µm near infrared light, transparent atmosphere in the visible light transmission characteristics much better than, because it close to the visible edge of the red light, linear transmission, reflection, refraction and absorption material and the physical characteristics very similar to visible light. Therefore, it can be used with similar visible focusing lens and other opticaldevices. Because infrared remote control is not as remote as the radio through the barrier to control the object's ability to control, so in the design of household appliances infra-red remote control, wireless remote control as unnecessary, each set (transmitters and receivers) have different frequency or remote coding (Otherwise, wall will control or interference with neighbors household appliances), all similar products in the infrared remote control, The same can control the frequency or coding, and no remote control signal "drop." This universal infrared remote control provides a great convenience. Infrared to visible light, is very subtle and confidentiality, therefore, the security, Alert and other security devices have been widely used. Infrared remote control is simple in structure and easy, low-cost, anti-interference capability, high reliability are a number of advantages, is a close-up remote control, especially in indoor remote control optimized manner.2.1.3 infrared diode characteristicsInfrared is not visible, people here are not aware of. Electronic technology is used infrared light emitting diode (also known as the IR emission diode) to generate infrared. Infrared remote control transceiver is using near-infrared transmission control instructions 0.76µm wavelength of ~ 1. 5µm. Near-infrared remote control as a light source, because there infrared light emitting diodes and infrared receiving device (photodiode. Transistor and PV) and the luminescence peak wavelength of light by the general 0.8µm ~ 0. 94µm. in the near-infrared band, both of the spectrum is the coincidence to a good match, access to higher transmission efficiency and higher reliability. Commonly used infrared diode, and its shape is similar LED light emitting diodes, Its basic circuit shown in figure 2 -2. The triode plans for the switch, when the base added a driving signal, Transistor saturated conduction infrared LED D is also Wizard Link, issued infrared (near infrared about 0.93 µm). D.The pressure drop of about 1.4 V and the current general for 10-20mA. To adapt to the working voltage of the D loop resistance often as a series of infrared diode current limit resistance.When the circuit diagram of the infrared emission control corresponding to the controlled device, the control of the distance and D is proportional to the transmitting power. In order to increase the distance of infrared control, infrared diode D should work on the pulse state that work is the lifeblood of current. Because pulse light (optical modulation) the effective transmission distance and pulse is proportional to the peak current, only maximize peak current Ip, will increase the infrared distance. Ip increase is a way to reduce the pulse duty cycle, that is compressed pulse width τsome TV infrared remote control, its infrared luminescence of the pulse duty cycle of about 1/4-1/3; Some electrical products infrared remote control, its duty cycle of 1 / 10. Decreasing pulse duty cycle also enable low-power infrared LED distance of the greatly increased. Common infrared light emitting diodes, power is divided into small power (1 mW - 10mW). Chinese power (20mW - 50mW) and power (50mW - 100mW more) three categories. Use different power infrared LED, the allocation should be driven by the corresponding power control. Figure 2 -2 by the reflected infrared light-emitting diodes to make produce optical modulation, Drivers only need to add the control of a certain frequency pulse voltage.Infrared transmitter and receiver in the way the two kinds of straight, and the second is reflective. Luminescence pointed straight pipe and tube receiver placed in a relatively controlled and fired on the two ends, a certain distance away from the middle; Reflective means luminescent tube and pipe parallel with the receiving peacetime, without always receiving tube light, luminescence only in possession of the infrared light reflected fromencountered, the receiving tube received from the reflected infrared before work.2.2 infrared communication basic tenets2.2.1 infrared communication PrincipleCommunication is the use of infrared wavelength of 900 nm-infrared waves from 1000 to serve as an information carrier, through infrared technology between the two close communication and confidentiality of information transmitted. Infrared communication system structure include : part launcher, channel, the receiver part.Launcher source letter issued after the binary signal from the high-frequency modulated infrared LED sent, receiving device regard the reception of high-frequency signals from the infrared receiver tube after receiving further demodulation photoelectric conversion of the original information of a mass communication lose way. Afterwards the former Information received after receiving part of the drive circuit connected to the expected completion of the various functions. To which the modulation coding style pulse width modulation (by changing the pulse width modulated signal PWM) and pulse modulation time (through change the pulse train interval time between the modulation signal PPM) two.2.2.2 infrared communication system elements(1) Launches : Currently there is a infrared wireless digital communications system sources of information including voice, data, images. Its methods of work for the launch of the receiver can be divided into different layout LOS way (Light-of-Sight , intracardiac way), diffuse (diffuse) mode. LOS way directional, it has good channel characteristics such advantages, but the existence of a "shadow" effect. difficult to achieve roaming function. Roaming means the main features of non-directional, and easy to implementroaming function, but its channel quality is better sometimes LOS way. Transmission of signals required for a few of (the sampling was quantified), the general need for baseband modulation, transmission, modulation, sometimes signal source coding, the above-driven signals from photoelectric converter complete optical signal transmission. Infrared wireless digital communications system and its scope of work-for-fired power distribution, the quality of the communication. While using various methods to improve optical transmitter power, the other using spatial diversity, holographic films and so on so diffuse light for the launch of space optical power evenly distributed.(2) Channel : infrared wireless digital communication channel refers to the transmitters and receivers in the space between. Due to natural light and artificial light sources such as light signals in the context of intervention, and the source - Electrical Equipment, The optical noise and disturbances, infrared wireless digital communications in some occasions, poor quality, At this point needed to channel coding. Infrared wireless communication system, the optical signal reflection, light scattering and background noise and interference effects, Infrared wireless digital channel presence multi-path interference and noise, This is to improve the quality and access for high-speed applications should be addressed. Infrared wireless digital communication channel often used by the major optical components, optical filter, condenser, their role is : plastic, filter, depending on the field transformation, the band division, the lens can be used as launch-ray focusing, the use of optical filters filter out stray light, the use of optical lenses to expand the field of view receiver, able to make use of optical components for the link frequency division multiplexing, etc.. Infrared wireless communication channel optical noise : the natural noise (sunlight) and anthropogenic interference (fluorescent lighting). can be modulated by the transmission technology such as filters and adding to be addressed.(3) receivers : Channel optical signal from the optical receiver partially photoelectric conversion, In order to remove noise and intersymbol interference and other functions. Infrared wireless digital communications system receiver include optical receiver parts and follow-up sampling, filtering, judgment, quantity, balanced and decoding part. Infrared wireless optical receiver often used amplifier, and called for large-bandwidth, high gain, low noise and low noise, frequency response and channel impulse response matched. To be suppressed by low-frequency noise and human disturbance needs a band-pass filter. To obtain large optical receiver scope and instantaneous field of view, often using spherical optical lens.2.2.3 infrared communications featureWireless communications are a lot of ways, some using infrared communication with the following characteristics :• The high frequency, wave length, and fired the energy concentrated space propagation attenuation coefficient can ensure the effective signal transmission;• infrared is the invisible light, strong confidentiality and use it as an information carrier. device when there is no visual pollution, it does no harm to the human body;• dissemination without limitation, and there is no question of frequency interference with radio-wave pattern, not on the spectrum resources to the relevant authorities for the application and registration, easy to implement;• has a good point, when the transmission equipment and infrared receiver ports line up straight, deviation of not more than about 15 degrees when infrared devices running the best effect;• through infrared or not bypassed and objects, data transmission, optical path can not be blocked;• currently produce and receive infrared signals in the technology is relatively mature, components small size, low cost production of simple, easy to produce and modulation advantages.2.3 infrared communication code based on the knowledgeUsually, infrared remote control transmitters will signal (pulse binary code) modulation at 38 KHz carrier, After buffer amplified sent to the infrared light-emitting diodes, infrared signals into firing away. Pulse binary code in a variety of formats. One of the most commonly used code is PWM (pulse width modulation code) and the PPM code (Pulse Code Modulation). The former said in a pulse width, pulse indicated 0. The latter pulse width, but the width of code-not the same, the codes represent a bit - and the digits represent narrow 0.Remote coding pulse signal (PPM code as an example) are usually guided by the code, the system code, the anti-code system, a feature code, functional anti-code signal components. Guide the code name for the initial code, by the width of 9 ms and the margin width of 4.5 ms to the low-level components (different remote control systems in the low-level high width of a certain distinction), remote coding used to mark the beginning of pulsed signals. System identification code is also called code, which used to indicate the type of remote control system, in order to distinguish other remote-control system, prevent the remote control system malfunction. Functional code is also called scripts, which represents the corresponding control functions, Receiver of the micro-controller functions under the numerical code to complete the various functions operating. Anti-code system and function codes are anti-system code and the functional code against code Anti-code can be joined to the receiver synchronization transmission process leads to errors. In order to improve performance and reduce interference power consumption, The remote control will be coded pulse frequency of 38 KHz (for the cycle of 26.3 ms) of the carrier signal pulse reshuffle system (PAM), and then sentto the buffer amplified infrared LED, the remote control signal transmitter away.Address code and data codes are composed of different pulse width expressed that the two narrow pulse "0"; 2 pulse width "1"; a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Is the first part of a group a group of code, each code synchronization between separated. The plan is to enlarge the second half of a group code : a code from 12 AD (the address code plus data code For example, eight address code plus four data code), each with two AD-Pulse's : Pulse said the two "0"; 2 pulse width "1"; a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Realize fired at each fired at least four groups code, PT2272 only twice in a row to detect the same address code plus data code data will be the code "1" is driven The data should be output to drive margin and VT terminal for synchronous serial.红外遥控系统摘 要红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。
光电信息科学与工程 英语
光电信息科学与工程英语Photonic information science and engineering is a fieldof study that focuses on the interaction between light and matter. It encompasses the study of light propagation, its interaction with matter and the development of devices thatare used in the processing and communication of information.In this article, we will explore step by step what the fieldof photonic information science and engineering entails.The first step in understanding photonic information science and engineering is to understand the physics of light. Light is electromagnetic radiation that moves at the speed of light (299,792,458 meters per second) in a vacuum. It is composed of photons, which are elementary particles that have no mass. The characteristics of light, such as its frequency and wavelength, determine how it interacts with matter.The second step is to understand the principles of photonics. Photonics is the science and technology of generating, manipulating and detecting photons. It encompasses a wide range of areas, such as optical communications, optical sensing, and light-based manufacturing. Photonics plays a vital role in the development of new technologies for information processingand communication, including optical fibers, optical amplifiers, and lasers.The third step is to understand the applications of photonic information science and engineering. This field has numerous applications, ranging from information technology to healthcare. Optical communication systems, such as fiber-optic networks, rely on the principles of photonics to transmit information over long distances. In healthcare, photonic devices are used for medical diagnostics, such as endoscopy and optical coherence tomography.The fourth step is to understand the research directions in photonic information science and engineering. This fieldis a rapidly advancing area of technology that is expanding into new areas, such as quantum photonics and optical computing. Quantum photonics uses the properties of quantum mechanics to generate and manipulate individual photons for quantum information processing. Optical computing aims to develop new computing architectures that use photons instead of electrons for computation.In conclusion, photonic information science and engineering is a fascinating field that combines physics, engineering, and computer science to develop new technologies and applications that rely on the properties of light. Understanding the principles of photonics, the physics of light, and the applications of this field is the first stepin unlocking the potential of photonic information science and engineering. Advances in this field promise to transform many aspects of our lives, from communication and computation to healthcare and beyond.。
外文文献--翻译--led显示屏
外文资料原文Large screen display system’s researchLed developmentAlong with computer technology’s high speed development，LED （Light Emitting Diode) the screen display system takes after the television, the broadcast, the newspaper, the magazine “the fifth big media” marches into the social life fast each aspect。
Its collection microelectronic technology, the computer technology, the information processing and management technology in a body, may the information through the writing, the design，the animation and the video frequency four forms demonstrates. With media and so on bank of television monitors，magnetism vane compares，the LED large screen display system has the design to be artistic，the color is sharp; The design，the color change are rich，are fast; The low power loss，the long life, the use cost low, work stably reliable and so on characteristics。
led照明毕业论文中英文资料外文翻译文献
led照明毕业论文中英文资料外文翻译文献Renewable and Sustainable Energy ReviewsHigh-brightness LEDs—Energy efficient lighting sources and their potential in indoor plant cultivation ABSTRACTThe rapid development of optoelectronic technology since mid-1980 has significantly enhanced the brightness and efficiency of light-emitting diodes (LEDs). LEDs have long been proposed as a primary light source for space-based plant research chamber or bioregenerative life support systems. The raising cost of energy also makes the use of LEDs in commercial crop culture imminent. With their energy efficiency, LEDs have opened new perspectives for optimizing the energy conversion and the nutrient supply both on and off Earth. The potentials of LED as an effective light source for indoor agriculturalproduction have been explored to a great extent. There are many researches that use LEDs to support plant growth in controlled environments such as plant tissue culture room and growth chamber. This paper provides a brief development history of LEDs and a broad base review on LED applications in indoor plant cultivation since 1990.Contents1. Introduction2. LED development.3. Color ratios and photosynthesis4. LEDs and indoor plant cultivation.4.1. Plant tissue culture and growth4.2. Space agriculture84.3. Algaculture4.4. Plant disease reduction5. Intermittent and photoperiod lighting and energy saving6. Conclusion1. IntroductionWith impacts of climate change, issues such as more frequent and seriousdroughts, floods, and storms as well as pest and diseases are becoming more serious threats to agriculture. These threats along with shortage of food supply make people turn to indoor and urban farming (such as vertical farming) for help. With proper lighting, indoor agriculture eliminates weather-related crop failures due to droughts and floods to provide year-round crop production, which assist in supplying food in cities with surging populations and in areas of severe environmental conditions.The use of light-emitting diodes marks great advancements over existing indoor agricultural lighting. LEDs allow the control of spectral composition and the adjustment of light intensity to simulate the changes of sunlight intensity during the day. They have the ability to produce high light levels with low radiant heat output and maintain useful light output for years. LEDs do not contain electrodes and thus do not burn out like incandescent or fluorescent bulbs that must be periodically replaced. Not to mention that incandescent and fluorescent lamps consume a lot of electrical power while generating heat, which must be dispelled from closed environments such as spaceships and space stations.2. LED developmentLED is a unique type of semiconductor diode. It consists of a chip of semiconductor material doped with impurities to create a p–n junction. Current flows easily from the p-side (anode), to the n-side (cathode), but not in the reverse direction.Electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The color (wavelength) of the light emitted depends on the band gap energy of the materials forming the p–n junction. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.The key structure of an LED consists of the die (or light-emitting semiconductor material), a lead frame where the die is placed, and the encapsulation which protects the die (Fig. 1).Fig.1LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors. J.Margolin reported that the first known light-emitting solid state diode was made in 1907 by H. J. Round. No practical use of Round’s diode was made for several decades until the invention of the first practical LED by Nick Holonyak, Jr in 1962. His LEDs became commercially available inlate 1960s. These GaAsP LEDs combine three primary elements: gallium, arsenic and phosphorus to provide a 655nm red light with brightness levels of approximately 1–10 mcd at 20mA. As the luminous intensity was low, these LEDs were only used in a few applications, primarily as indicators. Following GaAsP, GaP (gallium phosphide) red LEDs were developed. These device sex hibit very high quantum efficiencies at low currents. As LED technology progressed through the 1970s, additional colors and wavelengths became available. The most common materials were GaP green and red, GaAsP orange, and high efficiency red and GaAsP yellow. The trend towards more practical applications (such as in calculators, digital watches, and test equipment) also began to develop. As the LED materials technology became more advanced, the light output was increased, and LEDs became bright enough to be used for illumination.In 1980s a new material, GaAlAs (gallium aluminum arsenide) was developed followed by a rapid growth in the use of LEDs. GaAlAs technology provides superiorperformance over previously available LEDs. The voltage requirement is lower, which results in a total power savings. LEDs could be easily pulsed or multiplexed and thus are suitable for variable message and outdoor signs. Along this development period, LEDs were also designed into bar code scanners, fiber optic data transmission systems, and medicalequipment. During this time, the improvements in crystal growth and optics design allow yellow, green and orange LEDs only a minor improvement in brightness and efficiency. The basic structure of the material remained relatively unchanged.As laser diodes with output in the visible spectrum started to commercialize in late 1980s, LED designers used similar techniques to produce high-brightness and high reliability LEDs. This led to the development of InGaAlP (indium gallium aluminum phosphide) visible light LEDs. Via adjusting the energy band gap InGaAlP material can have different color output. Thus, green, yellow, orange and red LEDs could all be produced using the same basic technology. Also, light output degradation of InGaAlP material is significantly improved.Shuji Nakamura at Nichia Chemical Industries of Japan introduced blue LEDs in 1993. Blue LEDs have always been difficult to manufacture because of their high photon energies (>2.5 eV) and relatively low eye sensitivity. Also, the technology to fabricate these LEDs is very different and less advanced than standard LED materials. But blue is one of the primary colors (the other two being red and green). Properly combining the red, green, and blue light is essential to produce white and full-color. This process requires sophisticated software and hardware design to implement. In addition, the brightness level is low and the overall light output of each RGB die being used degrades at a different rate resulting in an eventual color unbalance. The blue LEDs available today consist of GaN (gallium nitride) and SiC (silicon carbide) construction. The blue LED that becomes available in production quantities has result in an entire generation of new applications that include telecommunications products, automotive applications, traffic control devices, and full-color message boards. Even LED TVs can soon become commercially available.Compare to incandescent light’s 1000-h and fluorescent light’s 8000-h life span, LEDs have a very significantly longer life of 100,000 h. In addition to their long life, LEDs have many advantages over conventional light source. These advantages include small size, specific wavelength, low thermal output, adjustable light intensity and quality, as well as high photoelectric conversion efficiency. Such advantages make LEDs perfect for supporting plant growth in controlled environment such as plant tissue culture room and growth chamber. Table 1 is a list of some common types of LEDs as compiled from .The chlorophyll molecules in plants initiate photosynthesis bycapturing light energy and converting it into chemical energy to help transforming water and carbon dioxide into the primary nutrient for living beings. The generalized equation for the photosynthetic process is given as:CO2 + H2O—light—>（CH2O）+ O2where (CH2O) is the chemical energy building block for thesynthesis of plant components.Chlorophyll molecules absorb blue and red wavelengths most efficiently. The green and yellow wavelengths are reflected or transmitted and thus are not as important in the photosyntheticprocess. That means limit the amount of color given to the plants and still have them grow as well as with white light. So, there is no need to devote energy to green light when energy costs are aconcern, which is usually the case in space travel.The LEDs enable researchers to eliminate other wavelengths found within normal white light, thus reducing the amount of energy required to power the plant growth lamps. The plants grow normally and taste the same as those raised in white light.Red and blue light best drive photosynthetic metabolism. These light qualities are particularly efficient in improving the developmental characteristics associated with autotrophic growth habits. Nevertheless, photosynthetically inefficient light qualities also convey important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. In addition, photoperiod (the adjustment of light and dark periods) and light quality (the adjustment of red, blue and far-red light ratio) also have decisive impacts on photomorphogenesis.The superimposed pattern of luminescence spectrum of blue LED (450–470 nm) and that of red LED (650–665 nm) corresponds well to light absorption spectrum of carotenoids and chlorophyll. Various plant cultivation experiments are possible when these twokinds of LED are used with the addition of far-red radiation (730–735 nm) as the light source. Along the line of the LED technology advancement, LEDs become a prominent light source for intensive plant culture systems and photobiological researches. The cultivation experiments which use such light sources are becoming increasingly active. Plant physiology and plant cultivation researches using LEDs started to peak in 1990s and become inevitable in the new millennium. Those researches have confirmed that LEDs are suitable for cultivation of a variety of algae,crop, flower, fruit, and vegetable.Some of the pioneering researches are reviewed in the followings.Bula et al. have shown that growing lettuce with red LEDs in combination with blue tubular fluorescent lamp (TFL) is possible. Hoenecke et al. have verified the necessity of blue photons for lettuce seedlings production by using red LEDs with blue TFL. As the price of both blue and red LEDs have dropped and the brightness increased significantly, the research findings have been able to be applied in commercial production. As reported by Agence France Press, Cosmo Plant Co., in Fukuroi, Japan has developed a red LED-based growth process that uses only 60% of electricity than a fluorescent lighting based one.Tennessen et al. have compared photosynthesis from leaves of kudzu (Pueraria lobata) enclosed in a leaf chamber illuminated by LEDs versus by a xenon arc lamp. The responses of photosynthesis to CO2 are similar under the LED and xenon arc lamps at equal photosynthetic irradiance. There is no statistical significant difference between the white light and red light measurements in high CO2. Some leaves exhibited feedback inhibition of photosynthesis which is equally evident under irradiation of either lamp type. The results suggest that photosynthesis research including electron transport, carbon metabolismand trace gas emission studies should benefit greatly from the increased reliability, repeatability and portability of a photosynthesis lamp based on LEDs.Okamoto et al. have investigated the effects of different ratios of red and blue (red/blue) photosynthetic photon flux density (PPFD) levels on the growth and morphogenesis of lettuce seedlings. They have found that the lettuce stem length decreases significantly with an increase in the blue PPFD. The research has also identified the respective PPFD ratio that (1) accelerates lettuce seedlings’stem elongation, (2) maximizes the whole plant dry weight, (3) accelerates the growth of whole plants, and (4) maximizes the dry weights of roots and stems. Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns), which is not easily achievable with other light sources. This rapid on–off feature has made LEDs an excellent light source for photosynthesis research such as pulsed lighting for the study of photosynthetic electron transport details. The off/dark period means additional energy saving on top of the LEDs’low power consumption.4. LEDs and indoor plant cultivation4.1. Plant tissue culture and growthTissue culture (TC), used widely in plant science and a number of commercial applications, is the growth of plant tissues or cells within a controlled environment, an ideal growth environment that is free from the contamination of microorganisms and other contaminants. A controlled environment for PTC usually means filtered air, steady temperature, stable light sources, and specially formulated growth media (such as broth or agar). Micropropagation, a form of plant tissue culture (PTC), is used widely in forestry and floriculture. It is also used for conserving rare or endangered plant species. Other uses of PTC include:1short-term testing of genetic constructions or regeneration oftrans genic plants,2 cross breeding distantly related species and regeneration of the novel hybrid,3 screening cells for advantageous characters (e.g. herbicidere sistance/tolerance),4embryo rescue (i.e. to cross-pollinate distantly related specie sand then tissue culture there sulting embryo which would normally die),5 large-scale growth of plant cells in liquid culture inside bioreactors as a source of secondary products (like recombinant proteins used as biopharmaceuticals).6production of doubled monoploid plants from haploid cultures to achieve homozygous lines more rapidly in breeding programs (usually by treatment with colchicine which causes doubling of the chromosome number).Tissue culture and growth room industries have long been using artificial light sources for production. These light sources include TFL, high pressure sodium lamp (HPS), metal halide lamp (MHL) and incandescent lamp, etc. Among them, TFL has been the most popular in tissue culture and growth room industries. However, the use of TFL consumes 65% of the total electricity in a tissue culture lab. That is the highest non-labor costs. As a result, these industries continuously seek for more efficient light sources. The development of high-brightness LED has made LED a promising light source for plant growth in controlled environments.Nhut et al. have cultured strawberry plantlets under different blue to red LED ratios as well as irradiation levels and compared its growth to that under plant growth fluorescent. The results suggest that a culture system using LED is advantageous for the micropropagation of strawberry plantlets. The study also demonstrates that the LED light source for in vitro culture of plantlets contributes to an improved growth of the plants in acclimatization.Brown et al. have measured the growth and dry matter partitioning of ‘Hungarian Wax’pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation. Pepper biomass reduces when grown under red LEDs without blue wavelengths compared to plants grown under supplemental blue fluorescent lamps. The addition of far-red radiation results in taller plants with greater stem mass than red LEDs alone. Fewer leaves developed under red or red plus far-red radiation than with lamps producing blue wavelengths. The results of their research indicate that with proper combination of other wavelengths, red LEDs may be suitable for the culture of plants in tightly controlled environments.4.2. Space agricultureBecause re-supply is not an option, plants are the only options to generate enough food, water and oxygen to help make future explorers self-sufficient at space colonies on the moon, Mars or beyond. In order to use plants, there must be a light source. Standard light sources that used in homes and in greenhouses and in growth chambers for controlled agriculture here on Earth are not efficient enough for space travel. While a human expedition outside Earth orbit still might be years away, the space farming efforts are aimed at developing promising artificial light sources. LEDs, because of their safety, small mass and volume, wavelength specificity, and longevity, have long been proposed as a primary light source for space-base plant research chamber or bioregenerative life support systems .Infrared LEDs that are used in remote controls devices have other uses. Johnson et al. have irradiated oat (Avena sativa cv Seger) seedlings with infrared (IR) LED radiation passed through a visible-light-blocking filter. The irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. This suggests that the oat seedlings are able to detect IR LED radiation. These findings also expand the defined range of wavelengths involved in radiation–gravity (light–gravity) interactions to include wavelengths in the IR region of the spectrum.Goins et al. grow wheat under red LEDs and compare them to the wheat grown under (1) white fluorescent lamps and (2) red LEDs supplemented with blue light from blue fluorescent lamps. The results show that wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to those grown under white light. Wheat grown under red LEDs + 10% BF light had comparable shoot dry matter accumulation and seed yield relative to those grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.The research of Goins and his team continues in plant growth chambers the size of walk-in refrigerators with blue and red LEDs to grow salad plants such as lettuce and radishes. They hope the plant growth chamber would enable space station staff to grow and harvest salad greens, herbs and vegetables during typical fourmonth tours on the outpost .4.3. AlgacultureAlgaculture, refers to the farming of species of algae, has been a great source for feedstock, bioplastics, pharmaceuticals, algae fuel, pollution control, as well as dyes and colorants. Algaculture also provides hopeful future food sources.Algae can be grown in a photobioreactor (PBR), a bioreactor which incorporates some type of light source. A PBR is a closed system, as opposed to an open tank or pond. All essential nutrients must be introduced into the system to allow algae to grow and be cultivated. A PBR extends the growing season and allows growing more species. The device also allows the chosen species to stay dominant. A PBR can either be operated in ‘‘batch mode’’or ‘‘continuous mode’’in which a continuous stream of sterilized water that contains air, nutrients, and carbon dioxide is introduced. As the algae grows, excess culture overflows and is harvested.When the algae grow and multiply, they become so dense that they block light from reaching deeper into the water. As a result, light only penetrates the top 7–10 cm of the water in most algalcultivation systems. Algae only need about 1/10 the amount of direct sunlight. So, direct sunlight is often too strong for algae. A means of supplying light to algae at the right concentration is to place the light source in the system directly.Matthijs et al. have used LEDs as the sole light source in continuous culture of the green alga (Chlorella pyrenoidosa). The research found the light output of the LED panel in continuous operation sufficient to support maximal growth. Flash operation at 5-ps pulse ‘‘on’’ duration between dark periods of up to 45 ps would stillsustain near maximum growth. While longer dark periods tend to cut the growth rate, the light flux decrease resulting from such operation does not reduce the growth as much as that of the similar flux decrease in continuous operation. Their research concludes that the use of flashing LEDs (which means intermittent light) in indoor algal culture yielded a major gain in energy economy comparing to fluorescent light sources. An additional advantage is that heat waste losses are much smaller. The most interesting discovery of this study may be that adding blue light to the red LED light did not change the growth properties.In order to take advantage of the biotechnological potential of algae, Lee and Palsson have calculated theoretical values of gas mass transfer requirements and light intensity requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. They have also designed a prototype PBR based on these calculations. Using on-line ultra filtration to periodically provide fresh medium, these researchers have achieved a cell concentration of more than 2×109cells/ml (more than 6.6%, vol/vol), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/l culture/h. This research indicates that the development of a small LED-based algal photobioreactors is economically achievable.Another research of algae via LEDs is conducted by Nedbal et al. Their research is a study of light fluctuation effects on a variety of algae in dilute cultures using arrays of red LEDs to provide intermittent and equivalent continuous light in small-size (30 ml) bioreactors. The results endorse that the algae growth rates in certain calculated intermittent light can be higher than the growth rate in the equivalent continuous light. Yanagi and Okamoto has grown five spinach plants under the red LEDs and another five under 40W plant growth fluorescent lamps at the same light intensity of 125 mmol/m2/s. The dry matter production under the LEDs is slightly less than that under the fluorescent lamps. The plant leaf area under the red LEDs is also smaller than that under the fluorescent lamps. Nevertheless, they reach a conclusion that LEDs can qualify as an artificial light source for plant growth.4.4.Plant disease reductionSchuerger and Brown have used LED arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. Their research concludes that spectral quality may alter plant disease development. Latter research regarding bacterial wilt on tomato has confirmed this conclusion and demonstrates that spectral quality may be useful as a component of an integrated pest management program for space-based ecological life support systems. Schuerger et al. have shown that the spectral quality effects on peppers’ anatomical changes in stem and leaf tissues are corr elated to the amount of blue light in primary light source.Miyashita et al. use red LEDs (peak wavelength: 660 nm) and white fluorescent lamps as light sources for potato plantlets growth in vitro. They found that shoot length and chlorophyll concentration of the plantlets increases with increasing 630–690 nm red photon flux (R-PF) while there are no significant differences in dry weight and leaf area of the plantlets with different R-PF levels. This means red lightaffects the morphology rather than the growth rate of potato plantlets in vitro. As a result, they suggest that red LEDs can be used for controlling plantlet morphology in micropropagation.5. Intermittent and photoperiod lighting and energy savingTime constants for photosynthetic processes can be divided into three ranges: primary photochemistry, electron shuttling, and carbon metabolism. These three photosynthetic processes can be uncoupled by providing pulses of light within the appropriate range for each process. At high frequencies, pulsing light treatments can be used to separate the light reactions (light harvesting and charge separation) from the dark reactions (electron shuttling) of photosynthetic electron transport. LEDs’ flexible pulsating ability can be coupled with such characteristics of photosynthesis and lead to additional energy saving.Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 mmol photons mp -2s-1 is provided during 1.5 ms pulses of 5000 mmol photons mp -2s-1 followed by 148.5 ms dark periods, photosynthesis is the same as in continuous 50 mmol photons mp -2s-1 . Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production.Jao and Fang have investigated the effects of intermittent light on growth of potato plantlets in vitro. They also use conventional TFLs for the experiment to explore the electrical savings realized by adjusting the frequency and duty ratio of LEDs. TFLs provide continuous fluctuating light at 60 Hz while LEDs provide nonfluctuating light and pulse light of the preset frequency and duty ratio. When the growth rate is the only concern, LEDs at 720 Hz (1.4 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod stimulated plant growth the most. When energy consumption is the major concern, using LEDs at 180 Hz (5.5 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod would not significantly sacrifice plant growth, especially when energy for heat removal is also taken into account.6. ConclusionsThe first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s when a lighting system for plant growth was designed for space shuttles and space stations for it is realized that people cannot go to the Moon, Mars, or beyond without first mastering the art of indoor farming on Earth. As the performance of LED continues to improve, these lighting systems progress from red only LED arrays using the limited components available to high-density, multi-color LED chip-on-board technologies. Today, space age gardeners who have been testing high-efficiency light sources for future space colonists have identified energy efficient LEDs as the major light source not only to grow food but also to generate and purify oxygen and water—key sustainers of human life. The removal of carbon dioxide from a closed environment is another added benefit.LEDs are the first light source to provide the capability of true spectral composition control, allowing wavelengths to match to plant photoreceptors to optimize production as well as to influence plant morphology and composition. They are easily integrated into digital control systems, facilitating complex lighting programs like varying spectral composition over the course of a photoperiod or with plant development stage. LEDs do not contain mercury. They are safer to operate than current lamps since they do not have glass envelopes or high touch temperatures.While the process of photosynthesis does not require continuous light of full spectrum, LEDs can produce sufficient photon fluxes of specific wavelength on and off rapidly. Such mechanism of photosynthesis coupled with the solid state characteristics of LEDs constitute two ways of energy saving (cutting out unnecessary spectrum segment and turning off the light periodically) on top of the LEDs’ low power consumption. These are not easily achievable with other light sources.This paper provides a broad base review on LED applications in horticulture industry since 1990. These researches pave the way for the researches of similar types using different species and lead to comparable conclusion that LEDs are well qualified to replace its more energy demanding counterparts as controlled environment light source for agricultural research such as providing tissue culture lighting as well as supplemental and photoperiod lighting for greenhouses.With the energy it can save, LED’s becoming ec onomically feasible in large-scale indoor farming lighting applications is just around the corner.再生可持续能源评论高亮高效节能LED灯的来源及其在室内植物栽培中的潜力摘要自1980年中期以来，光电子技术的迅猛发展，显著调高了发光二极管（LED）的亮度和效率。
光电信息科学与工程参考文献
光电信息科学与工程参考文献1. Ghatak, A., & Thyagarajan, K. (2013). Introductionto Fiber Optics. Cambridge University Press.这本书介绍了光纤通信的基本原理和技术，包括光纤的传输特性、光纤通信系统的设计和性能分析等。
2. Saleh, B. E. A., & Teich, M. C. (2007). Fundamentals of Photonics. John Wiley & Sons.这本书全面介绍了光子学的基础知识，包括光的传播、光的相互作用、光的检测和调制等。
3. Hecht, E. (2017). Optics. Pearson.这本书是光学领域的经典教材，涵盖了光学的基本原理和应用，包括光的传播、光的衍射和干涉、光的成像等内容。
4. Shen, Y. R. (1984). The Principles of Nonlinear Optics. Wiley.这本书介绍了非线性光学的基本原理和应用，包括非线性光学效应、非线性光学材料和器件等。
5. Saleh, B. E. A., & Teich, M. C. (1991). Fundamentals of Photonics. Wiley.这本书是光子学领域的经典教材，涵盖了光的传播、光的相互作用、光的检测和调制等内容。
6. Agrawal, G. P. (2012). Fiber-Optic Communication Systems. John Wiley & Sons.这本书详细介绍了光纤通信系统的原理和技术，包括光纤传输特性、光纤通信系统的组成和性能分析等。
7. Svelto, O. (2010). Principles of Lasers. Springer.这本书介绍了激光的基本原理和应用，包括激光的产生、激光的放大和调制、激光的应用等。
光电信息技术英语
光电信息技术英语In the heart of modern technological advancements lies the fascinating realm of optoelectronics, where light and electricity converge to revolutionize our world. This field, often dubbed the "language of the future," is shaping our communication, computing, and even our understanding of the cosmos. From the intricate dance of photons within fiberoptic cables that transmit information at blistering speeds, to the awe-inspiring advancements in solar energy that harness the sun's rays to power our homes, optoelectronics is the cornerstone of a greener, more connected planet.Imagine a world where data travels not through wires, but through beams of light, where the speed of communication is only limited by the speed of light itself. This is the promise of optoelectronic technology, which has already begun to transform industries. In healthcare, optoelectronic sensors are paving the way for non-invasive diagnostics, providing real-time monitoring of vital signs with unprecedented precision. In the automotive sector, the integration of light-based sensors is making our roads safer, with systems that can detect obstacles and adjust vehicle speed accordingly.As we delve deeper into the realm of optoelectronics, we encounter the cutting-edge technology of quantum computing, where the manipulation of individual photons holds the key to solving complex problems that are beyond the reach oftraditional computing. This is a technology that could unlock new frontiers in cryptography, drug discovery, and even artificial intelligence.But perhaps the most exciting aspect of optoelectronicsis its potential to make our world more sustainable. Solar panels, powered by optoelectronic principles, are becoming more efficient and affordable, pushing us closer to a future where clean, renewable energy is the norm. And as researchers continue to explore the boundaries of this field, we can expect to see even more innovative applications that will not only enrich our lives but also help us to preserve our planet for generations to come.The journey through the world of optoelectronics is one of discovery and wonder, a testament to human ingenuity and our unrelenting quest for knowledge. As we continue to push the boundaries of what is possible, the future looks brighter than ever, illuminated by the boundless potential of light and electricity.。
光电信息工程外文文献翻译
光电信息工程外文文献翻译(含：英文原文及中文译文)文献出处：N.M. Liao, W. Li, Y.D. Jiang, et al. Effects of gas temperature on optical and transport properties of a-Si:H films deposited by PECVD[J]. Philosophical Magazine, 2008, 88(25):3051-3057.英文原文中文译文气体温度通过PECVD 沉积对Si :H 薄膜的结构和光电性能的影响N.M. Liao ，W. Li ，Y.D. Jiang ，Z.M. Wu ，K.C. Qi摘要气体温度的影响(TG )在等离子体增强化学气相沉积法(PECVD )生长的薄膜的结构和光电特性:H 薄膜已使用多种表征技术研究。
气体的温度被确定为制备工艺的优化、结构和光电薄膜的性能改进的一个重要参数。
薄膜的结构性能进行了研究使用原子力显微镜(AFM ) ,傅立叶变换红外光谱(FTIR ) ,拉曼光谱,和电子自旋共振(ESR ) 。
此外,光谱椭偏仪(SE ) ,在紫外线–可见光区域的光传输的测量和电气测量被用来研究的薄膜的光学和电学性能。
它被发现在Tg 的变化可以修改的表面粗糙度,非晶网络秩序,氢键模式和薄膜的密度,并最终提高光学和电学性能。
1. 引言等离子体增强化学气相沉积法(PECVD )是氢化非晶硅薄膜制备一种技术,具有广泛的实际应用的重要材料。
它是用于太阳能电池生产,在夜视系统红外探测器,和薄膜晶体管的平板显示装置。
所有这些应用都是基于其良好的电气和光学特性以及与半导体技术兼容。
然而,根据a-Si 的性质, PECVD 制备H 薄膜需要敏感的沉积条件,如衬底温度,功率密度,气体流量和压力。
许多努力已经花在制备高品质的薄膜具有较低的缺陷密度和较高的结构稳定性的H 薄膜。
众所周知,衬底温度的强烈影响的自由基扩散的生长表面上,从而导致这些自由基更容易定位在最佳生长区。
光电信息科学与工程英语
光电信息科学与工程英语Optoelectronic Information Science and EngineeringOptoelectronic information science and engineering is an interdisciplinary field that combines the principles of electronics and photonics to enable the transmission and processing of information using light waves instead of electrical signals. This area of study has revolutionized the way we communicate and processes information, leading to the creation of new technologies such as fiber-optic communication systems and optoelectronic devices.As a result, it is essential for those working in optoelectronic information science and engineering to be proficient in English, the international language of science and technology. English proficiency allows professionals in this field to stay up-to-date with the latest research and developments, collaborate with international colleagues and communicate effectively with industry partners and clients.Key Terminology in Optoelectronic Information Science and EngineeringTo communicate effectively in this field, it is important to familiarize yourself with key terminology in optoelectronic information science and engineering. Here are some essential terms:1. Photonics: The science and technology of generating, detecting, and controlling photons, the fundamental particles of light.2. Optical Fiber: A thin, flexible, transparent fiber used to transmit light signals across long distances.3. Laser: A device that emits a highly focused beam of light that is both coherent and monochromatic.4. Modulator: A device that modulates (varies) the amplitude, phase or frequency of an optical signal.5. Photodetector: A device that converts light into an electrical signal.6. Attenuation: The loss of optical power as light travels along a fiber.7. Refraction: The bending of light when it passes through a material.In SummaryOptoelectronic information science and engineering is a rapidly growing field that is transforming the way we communicate and process information. Proficiency in English is essential for professionals working in this field to communicate effectively with international colleagues and industry partners. Familiarizing yourself with key terminology in optoelectronic information science and engineering is essential for successful collaboration, research, and development in this field.。
电子信息工程论文(英文)
Electronic and information engineering is the application of the computer and modem technology for electronic information control and information processing the discipline, the main research information acquisition and processing, electronic equipment and information system design, development, application and integration. Now, electronic and information engineering has covered many aspects of the society, like telephone exchange station how to deal with various phone signal, a mobile phone is how to transfer our voice even image, the network around us how to transfer data, and even of the army of the information age how to confidential information transmission, are involved in electronic and information engineering application technology. We can through some basic knowledge learning know these things, and able to apply more advanced technology in new product research and electronic and information engineering is professional This program is to cultivate master the modern electronic technology theory, familiar with electronic system design principle and design method, have stronger computer, foreign language and corresponding engineering technology application ability, facing the electronic technology, automatic control and intelligentcontrol, computer and network technology, electronic, information, communication field of broad caliber, the high quality, comprehensive development of integrated with innovation ability engineering technology talent development.Electronic information engineering major is learning the basic circuit of knowledge, and master the computer processing with the method of information. The first to have solid mathematical knowledge, for physics requirement is high, and mainly electrical; To learn many circuit knowledge, electronic technology, signal and system, computer control principle, communication principle, basic courses. Learning in electronic and information engineering design, to themselves have to connect with computer some circuit experiment, to operate and use tools requirements is also higher. Such as their connection sensor circuit, with computer set small communications system, will also visit some big company of electronic and information processing equipment, understanding mobile phone signal, cable TV is how to transmission, etc, and can organic ?Course classification:1. The mathematicsThe higher mathematics-(the department of mathematics mathematical analysis + space analytic geometry + ordinary differential equation) speak mainly is calculus, to learn thecircuit of the people, the calculus (a yuan, multiple), curve surface integral, series, ordinary differential equation, Fourier transform, the other the Laplace transformation in the subsequent frequently encountered in theory.Probability and statistics-all communication, signal processing with relevant course with probability theory.Mathematical physical methods-some school graduate student intellect, some schools into complex variable functions (+ integral transform) and mathematical physics equation (is partial differential equations). Study the mathematical basis of electromagnetic field, microwave.May also be introduced stochastic process (need to probability basis) and functional analysis.2. TheoryThe circuit principle-basic of the program.Signal and system, continuous and discrete signal time domain, frequency domain analysis, is very important but also is difficultDigital signal processing-discrete signal and system analysis, signal digital transformation, digital filters, and so on.The application of information theory, information theoryrange is very wide, but electronic engineering often put this course speak into coding theory.Electromagnetic field and wave-the day the course, basically is the counterpart of the dynamics in the physics department of the electricity, using mathematical to study the magnetic field (constant electromagnetic field, time-dependent electromagnetic fields).3. CircuitAnalog circuit-the transistor, the op-amp, power supply, A/D and D/A.Digital circuit--a gate, trigger and combination circuit, timing circuit, programmable devices, digital electronic system4. ComputerMicrocomputer principle-80 x86 hardware work principle.Assembly language, direct correspondence of the CPU commands programming language.Single chip microcomputer CPU and control circuit, made a piece of integrated circuit, all sorts of electric equipment of all necessary, normal explanation 51 series.Cc++ language-(now speak only c language schools may not much) writing system programming language, and the development of hardware related often are used.Software foundation-(computer specialized data structure + + + algorithm operating system database principles + compilation approach + software engineering) can also be a few course, speaks the principle of software and how to write software.Professional training requirements:This major is an electronic and information engineering major. Students of this specialty mainly studies the signal acquisition and processing, the power plant equipment information system of professional knowledge, by electronic and information engineering practice of basic training, with design, development, application and integrated electronic equipment and the ability of the information system.Professional training requirements:This major is an electronic and information engineering major. Students of this specialty mainly studies the signal acquisition and processing, the power plant equipment information system of professional knowledge, by electronic and information engineering practice of basic training, with design, development, application and integrated electronic equipment and the ability of the information system.The graduates should have the following several aspects of knowledge and ability:1. Can a system to manage the field wide technology basic theoretical knowledge, to adapt to the electronic and information engineering extensive work range2. Grasp the electronic circuit of the basic theory and experiment technology, analysis and design of electronic equipment basic ability3. To grasp the information acquisition, processing the basic theory and application of the general method, has the design, integration, application and computer simulation of information system of the basic skills.4. Understand the basic principles of information industry, policies and regulations, understand the basic knowledge of the enterprise management5. Understand electronic equipment and information system of theoretical frontiers, with research, development of new system, the new technology preliminary ability6. Master of literature retrieval, material inquires basic ?The future:Electronic information engineering major is learning the basic circuit of knowledge, and master the computer processing with the method of information. The first to have solid mathematical knowledge, for physics requirement is high, andmainly electrical; To learn many circuit knowledge, electronic technology, signal and system, computer control principle, communication principle, basic courses. Learning in electronic and information engineering design, to themselves have to connect with computer some circuit experiment, to operate and use tools requirements is also higher. Such as their connection sensor circuit, with computer set small communications system, will also visit some big company of electronic and information processing equipment, understanding mobile phone signal, cable TV is the ? how to transferAlong with the social informatization of thorough, the most industries need electronic and information engineering professionals, and a high salary. Students can be engaged in electronic equipment and information system design, application development and technical management, etc. For example, make electronic engineers, design develop some electronics, communication device; Do software engineer, hardware design, development and all kinds of relevant software; Do project executive, planning some big system, the experience, knowledge requires high; Still can continue to study to become a teacher, engaged in scientific research work, etc.China IT industry started so far have ten years, very young.Fresh things, chaoyang industry is always much attention. It is for this reason, the computer professional quickly become the university of popular major, many schoolmates sharpening again sharpened head to the ivory tower of ivory top drill, or for interest, or to make a living master a foreign skills, or for future better and faster development.The first few years of the computer professional than hot, in recent years professional to this choice in the gradually rational and objective. Students and parents consider is more of a more advantageous to the personal self based on long-term development of the starting point.In this industry, seems to have the potential law: a short career. So the body not old heart first, thought the "hope the way how to turn what should IT management, sales, or under IT the bodies from beginning to the past business, or simply turned... ., exactly what to do, still wandering in the, in the confusion, the code of a few years ago life seems to be erased it shall not plan, leaving only the deserted what some memories.Too much about the industry's bad, many, many elder's kind advice, in computer professional students in the heart of the buried the uneasy seeds, whether should continue to choose the bank, or career path should be explicit turn? Choose this line,is likely to mean that the choice of physical and mental suffering course, accept the industry of experience.Exit? Is the heart has unwilling, think about for several years hard work, they write in pencil full program writing paper, the class was, when working with the, less romantic hold lots of time, for the future is more a self-confidence to submitting a professional, the profound professional resume. Who would like to be the last into the heart to the east of the water flow.Any one industry all have their own bright and gloomy, just people don't understand. For just the us towards campus, has entered the society for seniors learn elder sister, for different positions of each elder, life is always difficult, brilliant casting is progressive, we can not only see industry bright beautiful beautiful appearance, and neglect of its growth lift behind the difficult, the gap between the two extremes of course huge, from such a perspective, apparently went against the objective. And for his future career build is the same, it's early form, its make, its cast, it's affluent, and it's thick, is a brick step by step a tired build by laying bricks or stones.Exactly do a "starter, don't want to entry-level, want to introduction and no entry-level" IT people, the answer at ease in each one.Can say electronic and information engineering is a promising discipline, is not optional despise any a subject. To do a line, loves a line, since choosing it, will it never do things by halves.on Electronic and information engineering is the application of the computer and modem technology for electronic information control and information processing the discipline, the main research information acquisition and processing, electronic equipment and information system design, development, application and integration. Now, electronic and information engineering has covered many aspects of the society, like telephone exchange station how to deal with various phone signal, a mobile phone is how to transfer our voice even image, the network around us how to transfer data, and even of the army of the informatiage how to confidential information transmission, are involved in electronic and information engineering application technology. We can through some basic knowledge learning know these things, and able to apply more advanced technology to research and development of new products.Electronic information engineering major is learning the basic circuit of knowledge, and master the computer processing with the method of information. The first to have solidmathematical knowledge, for physics requirement is high, and mainly electrical; To learn many circuit knowledge, electronic technology, signal and system, computer control principle, communication principle, basic courses. Learning in electronic and information engineering design, to themselves have to connect with computer some circuit experiment, to operate and use tools requirements is also higher. Such as their connection sensor circuit, with computer set small communications system, will also visit some big company of electronic and information processing equipment, understanding mobile phone signal, cable TV is how to transmission, etc, and can organic ?。
光电信息工程英语
光电信息工程英语Optoelectronic Information Engineering, also known as Optoelectronics, is a branch of engineering that deals with the study and application of electronic devices that interact with light. It involves the use of optics and electronics to design and develop devices such as lasers, photodetectors, optical fibers, and imaging systems.The field of Optoelectronic Information Engineering has become increasingly important in recent years due to the growing demand for high-speed and high-capacity communication systems. These systems are used in various applications such as data communication, medical imaging, military surveillance, and industrial control systems.Optoelectronic Information Engineering encompasses a wide range of technologies, including optical communication systems, fiber optics, photonic devices, and nanophotonics. Optical communication systems are used to transmit data over long distances using optical fibers, which offer high bandwidth and low loss. Fiber optics are also used in medical imaging and sensing applications due to their ability to transmit light through biological tissue.Photonic devices, such as lasers and photodetectors, areused in a variety of applications such as barcode scanners and laser printers. They are also used in fiber optic communication systems to transmit and receive data signals. Nanophotonics is an emerging field that involves the study and application of optical phenomena at the nanoscale, where the behavior of light is affected by the size and shape of the structures involved. In conclusion, Optoelectronic Information Engineering is a rapidly growing field that is essential to the development of many modern technologies. Its importance will only continue to increase as the demand for high-speed and high-capacity communication systems continues to grow.。
led照明中英文对照外文翻译文献
(文档含英文原文和中文翻译)中英文资料外文翻译文献Renewable and Sustainable Energy ReviewsHigh-brightness LEDs—Energy efficient lighting sources and their potential in indoor plant cultivation ABSTRACTThe rapid development of optoelectronic technology since mid-1980 has significantly enhanced the brightness and efficiency of light-emitting diodes (LEDs). LEDs have long been proposed as a primary light source for space-based plant research chamber or bioregenerative life support systems. The raising cost of energyalso makes the use of LEDs in commercial crop culture imminent. With their energy efficiency, LEDs have opened new perspectives for optimizing the energy conversion and the nutrient supply both on and off Earth. The potentials of LED as an effective light source for indoor agriculturalproduction have been explored to a great extent. There are many researches that use LEDs to support plant growth in controlled environments such as plant tissue culture room and growth chamber. This paper provides a brief development history of LEDs and a broad base review on LED applications in indoor plant cultivation since 1990.Contents1. Introduction2. LED development.3. Color ratios and photosynthesis4. LEDs and indoor plant cultivation.4.1. Plant tissue culture and growth4.2. Space agriculture84.3. Algaculture4.4. Plant disease reduction5. Intermittent and photoperiod lighting and energy saving6. Conclusion1. IntroductionWith impacts of climate change, issues such as more frequent and serious droughts, floods, and storms as well as pest and diseases are becoming more serious threats to agriculture. These threats along with shortage of food supply make people turn to indoor and urban farming (such as vertical farming) for help. With proper lighting, indoor agriculture eliminates weather-related crop failures due to droughts and floods to provide year-round crop production, which assist in supplying food in cities with surging populations and in areas of severe environmental conditions.The use of light-emitting diodes marks great advancements over existing indoor agricultural lighting. LEDs allow the control of spectral composition and the adjustment of light intensity to simulate the changes of sunlight intensity during the day. They have the ability to produce high light levels with low radiant heat output and maintain useful light output for years. LEDs do not contain electrodes and thus do not burn out like incandescent or fluorescent bulbs that must be periodically replaced. Not to mention that incandescent and fluorescent lamps consume a lot of electrical power while generating heat, which must be dispelled from closed environments such as spaceships and space stations.2. LED developmentLED is a unique type of semiconductor diode. It consists of a chip of semiconductor material doped with impurities to create a p–n junction. Current flows easily from the p-side (anode), to the n-side (cathode), but not in the reverse direction.Electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energyin the form of a photon. The color (wavelength) of the light emitted depends on the band gap energy of the materials forming the p–n junction. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.The key structure of an LED consists of the die (or light-emitting semiconductor material), a lead frame where the die is placed, and the encapsulation which protects the die (Fig. 1).Fig.1LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors. J.Margolin reported that the first known light-emitting solid state diode was made in 1907 by H. J. Round. No practical use of Round’s diode was made for several decades until the invention of the first practical LED by Nick Holonyak, Jr in 1962. His LEDs became commercially available inlate 1960s. These GaAsP LEDs combine three primary elements: gallium, arsenic and phosphorus to provide a 655nm red light with brightness levels of approximately 1–10 mcd at 20mA. As the luminous intensity was low, these LEDs were only used in a few applications, primarily as indicators. Following GaAsP, GaP (gallium phosphide) red LEDs were developed. These device sex hibit very high quantum efficiencies at low currents. As LED technology progressed through the 1970s, additional colors and wavelengths became available.The most common materials were GaP green and red, GaAsP orange, and high efficiency red and GaAsP yellow. The trend towards more practical applications (such as in calculators, digital watches, and test equipment) also began to develop. As the LED materials technology became more advanced, the light output was increased, and LEDs became bright enough to be used for illumination.In 1980s a new material, GaAlAs (gallium aluminum arsenide) was developed followed by a rapid growth in the use of LEDs. GaAlAs technology provides superior performance over previously available LEDs. The voltage requirement is lower, which results in a total power savings. LEDs could be easily pulsed or multiplexed and thus are suitable for variable message and outdoor signs. Along this development period, LEDs were also designed into bar code scanners, fiber optic data transmission systems, and medicalequipment. During this time, the improvements in crystal growth and optics design allow yellow, green and orange LEDs only a minor improvement in brightness and efficiency. The basic structure of the material remained relatively unchanged.As laser diodes with output in the visible spectrum started to commercialize in late 1980s, LED designers used similar techniques to produce high-brightness and high reliability LEDs. This led to the development of InGaAlP (indium gallium aluminum phosphide) visible light LEDs. Via adjusting the energy band gap InGaAlP material can have different color output. Thus, green, yellow, orange and red LEDs could all be produced using the same basic technology. Also, light output degradation of InGaAlP material is significantly improved.Shuji Nakamura at Nichia Chemical Industries of Japan introduced blue LEDs in 1993. Blue LEDs have always been difficult to manufacture because of their high photon energies (>2.5 eV) and relatively low eye sensitivity. Also, the technology to fabricate these LEDs is very different and less advanced than standard LED materials. But blue is one of the primary colors (the other two being red and green). Properly combining the red, green, and blue light is essential to produce white and full-color. This process requires sophisticated software and hardware design to implement. In addition, the brightness level is low and the overall light output of each RGB die being used degrades at a different rate resulting in an eventual color unbalance. The blue LEDs available today consist of GaN (gallium nitride) and SiC (silicon carbide) construction. The blue LED that becomes available in production quantities has result in an entire generation of new applications that include telecommunications products, automotive applications, traffic control devices, and full-color message boards. Even LED TVs can soon become commercially available.Compare to incandescent light’s 1000-h and fluorescent light’s 8000-h life span, LEDs have a very significantly longer life of 100,000 h. In addition to their long life, LEDs have many advantages over conventional light source. These advantages include small size, specific wavelength, low thermal output, adjustable light intensity and quality, as well as high photoelectric conversion efficiency. Such advantages make LEDs perfect for supporting plant growth in controlled environment such as plant tissue culture room and growth chamber. Table 1 is a list of some common types of LEDs as compiled from .The chlorophyll molecules in plants initiate photosynthesis bycapturing light energy and converting it into chemical energy to help transforming water and carbon dioxide into the primary nutrient for living beings. The generalized equation for the photosynthetic process is given as:CO2 + H2O—light—>（CH2O）+ O2where (CH2O) is the chemical energy building block for thesynthesis of plant components.Chlorophyll molecules absorb blue and red wavelengths most efficiently. The green and yellow wavelengths are reflected or transmitted and thus are not as important in the photosyntheticprocess. That means limit the amount of color given to the plants and still have them grow as well as with white light. So, there is no need to devote energy to green light when energy costs are aconcern, which is usually the case in space travel.The LEDs enable researchers to eliminate other wavelengths found within normal white light, thus reducing the amount of energy required to power the plant growth lamps. The plants grow normally and taste the same as those raised in white light.Red and blue light best drive photosynthetic metabolism. These light qualities are particularly efficient in improving the developmental characteristics associated with autotrophic growth habits. Nevertheless, photosynthetically inefficient light qualities also convey important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. In addition, photoperiod (the adjustment of light and dark periods) and light quality (the adjustment of red, blue and far-red light ratio) also have decisive impacts on photomorphogenesis.The superimposed pattern of luminescence spectrum of blue LED (450–470 nm) and that of red LED (650–665 nm) corresponds well to light absorption spectrum of carotenoids and chlorophyll. Various plant cultivation experiments are possible whenthese twokinds of LED are used with the addition of far-red radiation (730–735 nm) as the light source. Along the line of the LED technology advancement, LEDs become a prominent light source for intensive plant culture systems and photobiological researches. The cultivation experiments which use such light sources are becoming increasingly active. Plant physiology and plant cultivation researches using LEDs started to peak in 1990s and become inevitable in the new millennium. Those researches have confirmed that LEDs are suitable for cultivation of a variety of algae, crop, flower, fruit, and vegetable.Some of the pioneering researches are reviewed in the followings.Bula et al. have shown that growing lettuce with red LEDs in combination with blue tubular fluorescent lamp (TFL) is possible. Hoenecke et al. have verified the necessity of blue photons for lettuce seedlings production by using red LEDs with blue TFL. As the price of both blue and red LEDs have dropped and the brightness increased significantly, the research findings have been able to be applied in commercial production. As reported by Agence France Press, Cosmo Plant Co., in Fukuroi, Japan has developed a red LED-based growth process that uses only 60% of electricity than a fluorescent lighting based one.Tennessen et al. have compared photosynthesis from leaves of kudzu (Pueraria lobata) enclosed in a leaf chamber illuminated by LEDs versus by a xenon arc lamp. The responses of photosynthesis to CO2 are similar under the LED and xenon arc lamps at equal photosynthetic irradiance. There is no statistical significant difference between the white light and red light measurements in high CO2. Some leaves exhibited feedback inhibition of photosynthesis which is equally evident under irradiation of either lamp type. The results suggest that photosynthesis research including electron transport, carbon metabolismand trace gas emission studies should benefit greatly from the increased reliability, repeatability and portability of a photosynthesis lamp based on LEDs.Okamoto et al. have investigated the effects of different ratios of red and blue (red/blue) photosynthetic photon flux density (PPFD) levels on the growth and morphogenesis of lettuce seedlings. They have found that the lettuce stem length decreases significantly with an increase in the blue PPFD. The research has also identified the respective PPFD ratio that (1) accelerates lettuce seedlings’stem elongation, (2) maximizes the whole plant dry weight, (3) accelerates the growth of whole plants, and (4) maximizes the dry weights of roots and stems. Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns), which is not easily achievable with other light sources. This rapid on–off feature has made LEDs an excellent light source for photosynthesis research such as pulsed lighting for the study of photosynthetic electron transport details. The off/dark period means additional energy saving on top of the LEDs’low power consumption.4. LEDs and indoor plant cultivation4.1. Plant tissue culture and growthTissue culture (TC), used widely in plant science and a number of commercial applications, is the growth of plant tissues or cells within a controlled environment, anideal growth environment that is free from the contamination of microorganisms and other contaminants. A controlled environment for PTC usually means filtered air, steady temperature, stable light sources, and specially formulated growth media (such as broth or agar). Micropropagation, a form of plant tissue culture (PTC), is used widely in forestry and floriculture. It is also used for conserving rare or endangered plant species. Other uses of PTC include:1short-term testing of genetic constructions or regeneration oftrans genic plants,2 cross breeding distantly related species and regeneration of the novel hybrid,3 screening cells for advantageous characters (e.g. herbicidere sistance/tolerance), 4embryo rescue (i.e. to cross-pollinate distantly related specie sand then tissue culture there sulting embryo which would normally die),5 large-scale growth of plant cells in liquid culture inside bioreactors as a source of secondary products (like recombinant proteins used as biopharmaceuticals).6production of doubled monoploid plants from haploid cultures to achieve homozygous lines more rapidly in breeding programs (usually by treatment with colchicine which causes doubling of the chromosome number).Tissue culture and growth room industries have long been using artificial light sources for production. These light sources include TFL, high pressure sodium lamp (HPS), metal halide lamp (MHL) and incandescent lamp, etc. Among them, TFL has been the most popular in tissue culture and growth room industries. However, the use of TFL consumes 65% of the total electricity in a tissue culture lab. That is the highest non-labor costs. As a result, these industries continuously seek for more efficient light sources. The development of high-brightness LED has made LED a promising light source for plant growth in controlled environments.Nhut et al. have cultured strawberry plantlets under different blue to red LED ratios as well as irradiation levels and compared its growth to that under plant growth fluorescent. The results suggest that a culture system using LED is advantageous for the micropropagation of strawberry plantlets. The study also demonstrates that the LED light source for in vitro culture of plantlets contributes to an improved growth of the plants in acclimatization.Brown et al. have measured the growth and dry matter partitioning of ‘Hungarian Wax’pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation. Pepper biomass reduces when grown under red LEDs without blue wavelengths compared to plants grown under supplemental blue fluorescent lamps. The addition of far-red radiation results in taller plants with greater stem mass than red LEDs alone. Fewer leaves developed under red or red plus far-red radiation than with lamps producing blue wavelengths. The results of their research indicate that with proper combination of other wavelengths, red LEDs may be suitable for the culture of plants in tightly controlled environments.4.2. Space agricultureBecause re-supply is not an option, plants are the only options to generate enough food, water and oxygen to help make future explorers self-sufficient at space colonies on the moon, Mars or beyond. In order to use plants, there must be a lightsource. Standard light sources that used in homes and in greenhouses and in growth chambers for controlled agriculture here on Earth are not efficient enough for space travel. While a human expedition outside Earth orbit still might be years away, the space farming efforts are aimed at developing promising artificial light sources. LEDs, because of their safety, small mass and volume, wavelength specificity, and longevity, have long been proposed as a primary light source for space-base plant research chamber or bioregenerative life support systems .Infrared LEDs that are used in remote controls devices have other uses. Johnson et al. have irradiated oat (Avena sativa cv Seger) seedlings with infrared (IR) LED radiation passed through a visible-light-blocking filter. The irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. This suggests that the oat seedlings are able to detect IR LED radiation. These findings also expand the defined range of wavelengths involved in radiation–gravity (light–gravity) interactions to include wavelengths in the IR region of the spectrum.Goins et al. grow wheat under red LEDs and compare them to the wheat grown under (1) white fluorescent lamps and (2) red LEDs supplemented with blue light from blue fluorescent lamps. The results show that wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to those grown under white light. Wheat grown under red LEDs + 10% BF light had comparable shoot dry matter accumulation and seed yield relative to those grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.The research of Goins and his team continues in plant growth chambers the size of walk-in refrigerators with blue and red LEDs to grow salad plants such as lettuce and radishes. They hope the plant growth chamber would enable space station staff to grow and harvest salad greens, herbs and vegetables during typical fourmonth tours on the outpost .4.3. AlgacultureAlgaculture, refers to the farming of species of algae, has been a great source for feedstock, bioplastics, pharmaceuticals, algae fuel, pollution control, as well as dyes and colorants. Algaculture also provides hopeful future food sources.Algae can be grown in a photobioreactor (PBR), a bioreactor which incorporates some type of light source. A PBR is a closed system, as opposed to an open tank or pond. All essential nutrients must be introduced into the system to allow algae to grow and be cultivated. A PBR extends the growing season and allows growing more species. The device also allows the chosen species to stay dominant. A PBR can either be operated in ‘‘batch mode’’or ‘‘continuous mode’’in which a continuous stream of sterilized water that contains air, nutrients, and carbon dioxide is introduced. As the algae grows, excess culture overflows and is harvested.When the algae grow and multiply, they become so dense that they block light from reaching deeper into the water. As a result, light only penetrates the top 7–10 cm of the water in most algalcultivation systems. Algae only need about 1/10 theamount of direct sunlight. So, direct sunlight is often too strong for algae. A means of supplying light to algae at the right concentration is to place the light source in the system directly.Matthijs et al. have used LEDs as the sole light source in continuous culture of the green alga (Chlorella pyrenoidosa). The research found the light output of the LED panel in continuous operation sufficient to support maximal growth. Flash operation at 5-ps pulse ‘‘on’’ duration between dark periods of up to 45 ps would still sustain near maximum growth. While longer dark periods tend to cut the growth rate, the light flux decrease resulting from such operation does not reduce the growth as much as that of the similar flux decrease in continuous operation. Their research concludes that the use of flashing LEDs (which means intermittent light) in indoor algal culture yielded a major gain in energy economy comparing to fluorescent light sources. An additional advantage is that heat waste losses are much smaller. The most interesting discovery of this study may be that adding blue light to the red LED light did not change the growth properties.In order to take advantage of the biotechnological potential of algae, Lee and Palsson have calculated theoretical values of gas mass transfer requirements and light intensity requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. They have also designed a prototype PBR based on these calculations. Using on-line ultra filtration to periodically provide fresh medium, these researchers have achieved a cell concentration of more than 2×109cells/ml (more than 6.6%, vol/vol), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/l culture/h. This research indicates that the development of a small LED-based algal photobioreactors is economically achievable.Another research of algae via LEDs is conducted by Nedbal et al. Their research is a study of light fluctuation effects on a variety of algae in dilute cultures using arrays of red LEDs to provide intermittent and equivalent continuous light in small-size (30 ml) bioreactors. The results endorse that the algae growth rates in certain calculated intermittent light can be higher than the growth rate in the equivalent continuous light. Yanagi and Okamoto has grown five spinach plants under the red LEDs and another five under 40W plant growth fluorescent lamps at the same light intensity of 125 mmol/m2/s. The dry matter production under the LEDs is slightly less than that under the fluorescent lamps. The plant leaf area under the red LEDs is also smaller than that under the fluorescent lamps. Nevertheless, they reach a conclusion that LEDs can qualify as an artificial light source for plant growth.4.4.Plant disease reductionSchuerger and Brown have used LED arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. Their research concludes that spectral quality may alter plant disease development. Latter research regarding bacterial wilt on tomato has confirmed this conclusion and demonstrates that spectral quality may be useful as a component of an integrated pest management program for space-based ecological life support systems. Schuerger et al. have shown that the spectral qualityeffects on peppers’ anatomical changes in stem and leaf tissues are correlated to the amount of blue light in primary light source.Miyashita et al. use red LEDs (peak wavelength: 660 nm) and white fluorescent lamps as light sources for potato plantlets growth in vitro. They found that shoot length and chlorophyll concentration of the plantlets increases with increasing 630–690 nm red photon flux (R-PF) while there are no significant differences in dry weight and leaf area of the plantlets with different R-PF levels. This means red light affects the morphology rather than the growth rate of potato plantlets in vitro. As a result, they suggest that red LEDs can be used for controlling plantlet morphology in micropropagation.5. Intermittent and photoperiod lighting and energy savingTime constants for photosynthetic processes can be divided into three ranges: primary photochemistry, electron shuttling, and carbon metabolism. These three photosynthetic processes can be uncoupled by providing pulses of light within the appropriate range for each process. At high frequencies, pulsing light treatments can be used to separate the light reactions (light harvesting and charge separation) from the dark reactions (electron shuttling) of photosynthetic electron transport. LEDs’ flexible pulsating ability can be coupled with such characteristics of photosynthesis and lead to additional energy saving.Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 mmol photons mp -2s-1 is provided during 1.5 ms pulses of 5000 mmol photons mp -2s-1 followed by 148.5 ms dark periods, photosynthesis is the same as in continuous 50 mmol photons mp -2s-1 . Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production.Jao and Fang have investigated the effects of intermittent light on growth of potato plantlets in vitro. They also use conventional TFLs for the experiment to explore the electrical savings realized by adjusting the frequency and duty ratio of LEDs. TFLs provide continuous fluctuating light at 60 Hz while LEDs provide nonfluctuating light and pulse light of the preset frequency and duty ratio. When the growth rate is the only concern, LEDs at 720 Hz (1.4 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod stimulated plant growth the most. When energy consumption is the major concern, using LEDs at 180 Hz (5.5 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod would not significantly sacrifice plant growth, especially when energy for heat removal is also taken into account.6. ConclusionsThe first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s when a lighting system for plant growth was designed for space shuttles and space stations for it is realized that people cannot go to the Moon, Mars, or beyond without first mastering the art of indoor farming on Earth. As the performanceof LED continues to improve, these lighting systems progress from red only LED arrays using the limited components available to high-density, multi-color LED chip-on-board technologies. Today, space age gardeners who have been testing high-efficiency light sources for future space colonists have identified energy efficient LEDs as the major light source not only to grow food but also to generate and purify oxygen and water—key sustainers of human life. The removal of carbon dioxide from a closed environment is another added benefit.LEDs are the first light source to provide the capability of true spectral composition control, allowing wavelengths to match to plant photoreceptors to optimize production as well as to influence plant morphology and composition. They are easily integrated into digital control systems, facilitating complex lighting programs like varying spectral composition over the course of a photoperiod or with plant development stage. LEDs do not contain mercury. They are safer to operate than current lamps since they do not have glass envelopes or high touch temperatures.While the process of photosynthesis does not require continuous light of full spectrum, LEDs can produce sufficient photon fluxes of specific wavelength on and off rapidly. Such mechanism of photosynthesis coupled with the solid state characteristics of LEDs constitute two ways of energy saving (cutting out unnecessary spectrum segment and turning off the light periodically) on top of the LEDs’ low power consumption. These are not easily achievable with other light sources.This paper provides a broad base review on LED applications in horticulture industry since 1990. These researches pave the way for the researches of similar types using different species and lead to comparable conclusion that LEDs are well qualified to replace its more energy demanding counterparts as controlled environment light source for agricultural research such as providing tissue culture lighting as well as supplemental and photoperiod lighting for greenhouses.With the energy it can save, LED’s becoming economically feasible in large-scale indoor farming lighting applications is just around the corner.再生可持续能源评论高亮高效节能LED灯的来源及其在室内植物栽培中的潜力摘要自1980年中期以来，光电子技术的迅猛发展，显著调高了发光二极管（LED）的亮度和效率。
光电信息科学与工程 专业描述‘
英文回答：The Optoelectronic Information Science and Engineering major is dedicated to theprehensive study of the principles and practical applications of optoelectronic devices and systems. This field epasses the thorough exploration of light-matter interactions, photonics, and the utilization of light in various engineering systems and devices. Students pursuing this major will delve into a wide range of topics, including but not limited to semiconductor physics, opticalmunications, imaging and display technologies, and optoelectronic materials. The primary objective of this major is to provide students with a solid understanding of the fundamental concepts of optoelectronic technology and the capability to effectively apply this knowledge to address diverse engineering challenges.光电子信息科学与工程专业致力于光电子设备和系统原理和实际应用的综合研究。
(光电信息工程专业英语)专业英语第七讲Geometrical Optics
牛顿1672年使用的6英寸反射式望远镜复制品，为皇 家学会所拥有。
1994年，不列颠哥伦比亚大学开始建造一台 口径为6米的旋转水银面望远镜——大型天 顶望远镜（LZT），并于2003年建成
1.9 Lens Aberrations
9. By choosing materials with indices of refraction that depend in different ways on the color of the light, lens designers can ensure that positive and negative lens elements compensate for each other by having equal but opposite chromatic effects.
1.9 Lens Aberrations
4. Up to now, our discussion of lenses has not taken into account some of the optical imperfections that are inherent in single lenses made of uniform material with spherical surfaces. These failures of a lens to give a perfect image are known as aberrations. 句子结构： our discussion … has not taken into account … imperfections…
vt.提供；给予（provide的过去式）
参考翻译：
在上述的推导中，我们检验了物在会聚透镜焦点以外的特殊情况。 然而，如果遵守下述的符号规则，薄透镜公式对于会聚和发散薄透镜都是 有效的，且不论物体远近。
光伏发电技术中英文资料外文翻译文献
光伏发电技术中英文资料外文翻译文献Research Article 1: Title of the ArticleAbstractResearch Article 2: Title of the ArticleAbstractThis research article focuses on the environmental impact of PV technology. It explains how solar panels convert sunlight into electricity and highlights the role of PV systems in reducing greenhouse gas emissions. The article discusses the benefits and challenges associated with PV technology, including its dependence on sunlight, land requirements, and recyclability of materials. It also examines the life cycle assessment (LCA) of PV systems to evaluate their overall environmental performance. The research concludes by suggesting strategies to mitigate the environmental impact of PV technology, suchas improving panel efficiency and implementing responsible recycling practices.Research Article 3: Title of the ArticleAbstractThis article explores the economic aspects of PV technology. It analyzes the cost of installing and maintaining PV systems, including considerations for equipment, installation, and operation. The research discusses various financial incentives, such as government subsidies and tax credits, that promote the adoption of PV technology. It also highlights the economic benefits of PV systems, including job creation and energy independence. The article concludes by discussing the future potential of PV technology in reducing energy costs and stimulating economic growth.Research Article 4: Title of the ArticleAbstractThe focus of this research article is on the technical advancements in PV technology. It discusses the development of new materials and manufacturing processes to improve the efficiency and reliability of solar panels. The article explores the integration of PV systems with smart grid technology and how it enables better management of electricity generation and consumption. It also highlights the role of artificial intelligence and machine learning in optimizing PV system performance. The research concludes by suggesting future research directions in PV technology, such as exploring nanomaterials and enhancing the intelligence of PV systems.Conclusion总结这份文献收录了关于光伏发电技术的各个方面的研究，涵盖了与环境影响、经济考量和技术进展相关的主题。
光电子英文文献
Stimulated Brillouin scattering and its dependences on strain and temperature in a high-delta opticalfiber with F-doped depressed inner cladding Weiwen Zou,Zuyuan He,Masato Kishi,and Kazuo HotateDepartment of Electronic Engineering,University of Tokyo,Tokyo113-8656,JapanReceived September7,2006;revised November27,2006;accepted December8,2006;posted December11,2006(Doc.ID74831);published February15,2007 Stimulated Brillouin scattering(SBS)in a high-deltafiber with F-doped depressed inner cladding is studied through considering the interaction of acoustic and optical modes in thefiber.It is found that the number of acoustic modes in thefiber is reduced and the frequency spacing between neighboring modes is enlarged because of the F doping.The dependences of SBS on strain and temperature are measured and compared for each acoustic mode to investigate the feasibility of discriminative sensing of strain and temperature by use of thefiber.©2007Optical Society of AmericaOCIS codes:290.5900,120.5820,060.2310,060.2270,060.2370.Brillouin-based distributedfiber optic sensors1–3at-tract a great deal of interest for their potential appli-cations in smart materials and smart structures. These sensors,however,suffer difficulty in distin-guishing responses to strain from responses to tem-perature change with a singlefiber.To overcome the difficulty,researchers recently explored the utiliza-tion of two different Brillouin resonance peaks whose frequencies show different dependences on strain and temperature infibers.So far,a large-effective-area nonzero-dispersion-shiftedfiber4and a photonic crystalfiber with a small core of high germanium doping5have been investigated.Relatively,the latter approach gives a higher strain–temperature accuracy because the utilized second peak is said to originate from the acoustic antiwaveguide in thefiber.5This method,however,is limited in application because of the presence of multiple subpeaks with close fre-quency spacing in the Brillouin gain spectrum(BGS), which are hard to separate in measurement.In this Letter we investigate the stimulated Bril-louin scattering(SBS)in a high-delta opticalfiber with F-doped depressed inner cladding(F-HDF).Our simulation and measurement show that the BGS of the F-HDF has fewer acoustic modes and larger reso-nance frequency spacing between neighboring modes compared with a normal high-deltafiber(HDF)with the same core and cladding but without the inner cladding.The F-HDF,supplied by Fujikura Ltd.,has a highly GeO2-doped core(radiusϳ3.65m),a ϳ1wt.%F-doped depressed inner cladding(radiusϳ17m),and a pure-silica cladding(radius 62.5m).Compared with thefiber samples demon-strated in Ref.6,our F-HDF sample has a greater GeO2concentration with a maximum ofϳ24mol.%, and its F-doped region is part of the claddings.Figure 1(a)depicts the modeled refractive index profile(solid curve)and the acoustic velocity profile(dashed curve) that is deduced according to Ref.7.The profiles show that the depressed inner cladding for optical modes is an enhanced inner cladding for acoustic modes and then forms a second acoustic waveguide with respect to pure-silica cladding.By using our newly proposed two-dimensionalfinite-element modal analysis8on the profiles in Fig.1(a),we simulate the BGS in F-HDF(solid curve)and that in HDF(dotted curve) as shown in Fig.1(b).Here we assume that the F-HDF and HDF guide only the fundamental opticalLP01mode,although the average normalized fre-quency v value9is estimated asϳ2.95.This assump-tion is reasonable for the F-HDF because its de-pressed F-doped region enhances the normalizedcutoff v value of the optical LP11mode,which can be understood qualitatively from Ref.9.Figure1(b) shows that,by the F-doping,the number of total acoustic modes is reduced(six modes in HDF to four modes in F-HDF)and the frequency spacing between neighboring modes is enlarged(for example,ϳ320MHz in HDF between the second-order mode and the third-order mode is enlargedϳ400MHz in F-HDF).According to the calculation of the four acoustic modes’effective phase velocities(5058,5271,5470,and5645m/s,respectively)as marked in Fig.1(a),all four acoustic modes(L01,L02,L03,and L04)existing in F-HDF are located in the GeO2core region in terms of their effective phase velocities,but the higher-order mode is closer to the F-doped inner-cladding region.The difference in the BGS of F-HDF from that of HDF originates from the decrease of the average acoustic velocity in the claddings induced by the F-doped inner-cladding region,which resultsinFig.1.(Color online)(a)Modeled refractive index profile (solid curve)and the deduced acoustic velocity profile (dashed curve)in F-HDF,where⌬corresponds to the rela-tive difference of the refractive index and V l is the acoustic velocity.The marked points show the effective phase veloci-ties of different acoustic modes.(b)Simulated BGS in F-HDF(solid curve)and in HDF(dotted curve).600OPTICS LETTERS/Vol.32,No.6/March15,20070146-9592/07/060600-3/$15.00©2007Optical Society of Americathe cutoff of the fifth-͑L 05͒and sixth-order ͑L 06͒acoustic modes and then the increase of the fre-quency spacing.The experimental setup for SBS measurement is depicted in Fig.2.The pump and the probe waves are equally divided from a 1.549-m distributed-feedback laser diode (DFB-LD).The pump wave is amplified with an erbium-doped fiber amplifier (EDFA)to ϳ20dBm and chopped at 8.3MHz for lock-in detection.The probe wave frequency has a downshift B from the pump wave through a single-sideband modulator (SSBM).To compensate for the loss in the SSBM,two additional EDFAs are inserted before and after the SSBM,respectively.The probe power launched into the fiber under test (FUT),the F-HDF,is ϳ2.3dBm.A variable optical attenuator (VOA)is used to prevent saturation of the photode-tector (PD).As shown in inset A,a water bath of ±0.1°C accuracy is used to control the temperature of the FUT.The FUT is coated with only a 250-m acry-late jacket,so that the coating’s influence on the tem-perature dependence can be neglected.The 4.74m FUT spliced to two 5cm standard single-mode fiber pigtails of an isolator and a circulator is handwound around a couple of drums with a diameter of 110mm to depress the influence of bending-induced birefringence.10The drums are inserted into the wa-ter bath and mounted on an x stage set for applying strain.The typical BGS of the F-HDF measured at 25°C in the loose state is depicted in Fig.3,in which the simulated BGS is also drawn for comparison.The measured result is in good agreement with the simu-lation except for a few frequency discrepancies that are possibly due to the influence from the leaky acoustic modes 11not considered in the simulation.By controlling the microwave frequency for SSBM at each temperature or strain setting,we measured the BGS corresponding to the four acoustic modes (i.e.,L 01,L 02,L 03,and L 04modes).Then we fitted each to a Lorenzian function with an offset to find each reso-nance frequency B pk i .Figures 4(a)–4(d)depict the results measured at 25°C in the loose state as an ex-ample.The solid curves represent the Lorenzian fits,which match very well with the experimental data.The resonance frequencies B pk i are 9.3930,9.7572,10.1539,and 10.5645GHz,respectively.The resonance frequencies B pk i and B pk j of two different peaks (peak i and peak j )in BGS simulta-neously affected by the applied strain and tempera-ture change are governed by the following relation:ͩ⌬B pk i ⌬B pk jͪ=ͩA i B i A j B jͪͩ⌬⑀⌬Tͪ,͑1͒where A i ͑j ͒and B i ͑j ͒correspond to the coefficients of strain and temperature for peak i ͑j ͒,respectively.Here we introduce a coefficient difference ratio ␥Aij or ␥Bij to let A j =A i ͑1+␥Aij ͒and B j =B i ͑1+␥Bij ͒.From Eq.(1),we know that whether the strain and tempera-ture can be distinguished is determined only by the following condition:␥Aij ␥Bij .͑2͒In fact,the Brillouin-based sensor system possesses a frequency measurement uncertainty ͑␦͒,which in-duces discrimination errors in strain ͑␦⑀ij ͒and tem-perature ͑␦T ij ͒.The strain and temperature errors can be estimatedbyFig.2.(Color online)Experimental setup of SBS measure-ment.Inset A,schematic control of the temperature and the strain on the FUT.EOM,electro-optic modulator;PC,polarization controller;VOA,variable optical attenuator;DAQ,dataacquisition.Fig.3.(Color online)Typical BGS measured at 25°C in loose state (dotted curve)compared with the simulated BGS (solid curve)in the F-HDF.Bottom axis,measured BGS;top axis,simulatedBGS.Fig.4.(Color online)Measured BGS (dots)at 25°C in loose state and Lorenzian fittings (solid curves)for (a)first-order ͑L 01͒,(b)second-order ͑L 02͒,(c)third-order ͑L 03͒,and (d)fourth-order ͑L 04͒acoustic mode scattering.March 15,2007/Vol.32,No.6/OPTICS LETTERS 601␦⑀ij =͉ͯ1+␥Bij ͉+1A i ͑␥Bij −␥Aij ͒ͯ␦,␦T ij =͉ͯ1+␥Aij ͉+1B i ͑␥Bij −␥Aij ͒ͯ␦,͑3͒respectively,which show that the measurement error becomes smaller if the value of ͉␥Bij −␥Aij ͉is greater.Figure 5depicts the measured resonance frequency of each acoustic mode in the F-HDF as a function of strain and temperature.Note here that the tempera-ture dependence is measured in the loose state and that the strain dependence is measured at 25°C.By using least-squares linear fitting,we get the strain coefficient A i and temperature coefficient B i for each acoustic mode scattering.As summarized in Table 1,the difference ratios of ␥Aij and ␥Bij of the higher-order scatterings with respect to the first-order scat-tering satisfy condition (2)better,providing feasibil-ity to employ the fiber for discriminating the response to strain from the response to temperature by using the first-order scattering as the reference and higher-order (e.g.,the fourth-order)scattering as the second peak,respectively.The frequency uncertainty ␦in our measurement is 0.1MHz according to a repeatability test.Based on Eq.(3),the strain errors and the temperature errors in using the F-HDF for discriminative measurements are summarized in Table 1.For the second-order acoustic mode,the errors are 55⑀and 2.4°C,re-spectively.The fourth-order acoustic mode gives the smallest discrimination errors because of its greatest ͉␥Bij −␥Aij ͉.This is probably due to the different re-sidual stress in the core region and the inner clad-ding induced during the fabrication of the fiber.12Therefore the higher-order acoustic mode located closer to the F-doped inner cladding shows a greater difference with respect to strain and temperature.However,for the measured F-HDF,the performance of the fourth-order acoustic mode scattering in dis-criminative measurement of strain and temperature is not satisfactory,because its effective acoustic phase velocity is still located in the core region [see Fig.1(a)],although it is closer to the inner-cladding region compared with the second-and third-order.Also,the Brillouin gain of the fourth-order is rela-tively lower (see Fig.3).This result suggests that fur-ther improvement is possible with properly designed core and inner-cladding regions to move the effective velocity of a higher-order acoustic mode (e.g.,second-or third-order)into the inner cladding region and to enhance its Brillouin gain relative to the first-order acoustic mode.In conclusion,we have investigated the SBS in an F-HDF and its dependences on strain and pared with the BGS in normal HDF,the acoustic modes in F-HDF are found to be modified by the F-doped inner cladding,resulting in fewer acous-tic modes appearing in the core region and a wider frequency spacing between neighboring modes.We also discussed the feasibility of using the F-HDF for discriminative measurement of strain and tempera-ture by utilizing behaviors of the higher-order scat-terings that differ from the first-order one.The cur-rent performance is expected to be improved by properly designing the core region and the inner-cladding region.The authors are grateful to Mr.Akira Wada of Fujikura Ltd.for providing the F-HDF sample.W.Zou’s e-mail address is zou@sagnac.t.u.-tokyo.ac.jp.References1.K.Hotate and M.Tanaka,IEEE Photon.Technol.Lett.14,179(2002).2.K.Hotate and S.S.L.Ong,IEEE Photon.Technol.Lett.15,272(2003).3.M.Nikles,L.Thevenaz,and P .Robert,Opt.Lett.21,758(1996).4.C.C.Lee,P .W.Chiang,and S.Chi,IEEE Photon.Technol.Lett.13,1094(2001).5.L.Zou,X.Bao,S.Afshar,and L.Chen,Opt.Lett.29,1485(2004).6.N.Shibata,K.Okamoto,and Y.Azuna,J.Opt.Soc.Am.B 6,1167(1989).7.Y.Koyamada,S.Sato,S.Nakamura,H.Sotobayashi,and W.Chujo,J.Lightwave Technol.22,631(2004).8.W.Zou,Z.He,and K.Hotate,IEEE Photon.Technol.Lett.18,2487(2006).9.M.Monerie,IEEE J.Quantum Electron.18,532(1982).10.R.Ulrich,S.C.Rashleigh,and W.Eickhoff,Opt.Lett.5,273(1980).11.S.Afshar,V .P .Kalosha,X.Bao,and L.Chen,Opt.Lett.30,2685(2005).12.Y.Park,K.Oh,U. C.Paek, D.Y.Kim,and C.R.Kurkjian,J.Lightwave Technol.17,1823(1999).Table 1.Strain and Temperature Coefficients andDiscriminative Measurement Errors for Various Acoustic Modes in F-HDF Parameters 1st Order 2nd Order 3rd Order 4th Order A i ͑MHz/⑀͒0.031640.031940.031900.0330B i (MHz/°C)0.69570.78760.80610.8342␥A 1j —0.00960.00820.0430␥B 1j —0.13210.15880.1992͉␥B 1j -␥A 1j ͉—0.12250.15050.1562␦⑀1j ͑⑀͒—554544␦T 1j (°C)—2.41.91.8Fig.5.(Color online)Resonance frequencies of different acoustic modes as a function of (a)strain and (b)tempera-ture.Solid lines,least-squares linear fits to data.Their slope rates,strain coefficients A i ,and temperature coeffi-cients B i are summarized in Table 1.602OPTICS LETTERS /Vol.32,No.6/March 15,2007。
光学信息工程外文翻译
Photographic ObjectivesIn this section, we will outline the basic design principles of the photographicobjective, and for this purpose we will classify objectivesaccording to their relationship to, or derivation from, a few major categories:(a) meniscus types, (b) Cooke triplet types, (c) Petzval types,and (d) telephoto types. These categories are quite arbitrary and are chosen for their value as illustrations of design features rather than any historic or generic implications.In this category, we include those objectiveswhich derive their field correction primarily from the use of a thick meniscus. As mentioned in Secs. 12.1 and 12.2, a thick-meniscus element has a greatly reduced inward Petzval curvature in comparisonwith a biconvex element of the same power; indeed, the Petzval sum can be overcorrected if the thickness is made great enough. The simplest example of this type of lens is the Goerz Hypergon (Fig. 12.4)which consists of two symmetrical menisci. Because the convex and fact that the surfaces are nearly concentric about the stop enablesthe lens to cover an extremely wide (135°) field, although at a very low aperture (f/30).To obtain an increased aperture, it is necessary to correct the spherical and chromatic aberrations. This can be accomplished by the additionof negative flint elements, as in the Topogon lens, Fig. 13.10. Note that the construction of this lens is also very nearly concentric about the stop; lenses of this type cover total fields of 75° to 90° at speeds off/6.3 to f/11.To obtain an increased aperture, it is necessary to correct the sphericaland chromatic aberrations. This can be accomplished by the additionof negative flint elements, as in the Topogon lens, Fig. 13.10. Note that the construction of this lens is also very nearly concentric about the stop; lenses of this type cover total fields of 75° to 90° at speeds off/6.3 to f/11. symmetry helps to control the coma and distortion. Lenses of theProtar type cover total fields of 60° to 90° at speeds of f/8 to f/18.A few years later, Rudolph and von Hoegh (Goerz), working independently, combined the two components of the Protar into a singlecemented component, which contained both the required dispersingand collective cemented surfaces. The Goerz Dagor is shown in Fig. 13.12, and is composed of a symmetrical pair of cemented triplets. Each half of such a lens can be designed to be corrected independentlyso that photographers were able to remove the front component toget two different focal lengths. A great variety of designs based on this principle were produced around the turn of the century, using three, four, and even five cemented elements in each component, although very little was gained from the added elements. Protars and Dagors are still used for wide-angle photography because of the fine definition obtained over a wide field, especially when used at a reduced aperture. See Fig. 14.14 for an example of a Dagor design.The additional degree of freedom gained by breaking the contact of the inside crowns of the Dagor construction proved to be of more value than additional elements. Lenses of this type (Fig. 13.13) are probably the best of the wide-angle meniscus systems and cover fields upto 70° total at speeds of f/5.6 (or faster for smaller fields). The Meyer Plasmat, the Ross W. A. Express, and the Zeiss Orthometar are of this construction, and recently excellent 1:1 copy lenses (symmetrical) have been designed for photocopy machines. Note that the broken contact allows the inner crown to be made of a higher-index glass.The design of the thick-meniscus anastigmats is a complex undertaking because of the close interrelationship of all the variables. In general the exterior shape and thickness are chosen to control the Petzval sum and power, and the distance from the stop can be used to adjust the astigmatism. However, the adjustment of element powersto correct chromatic inevitably upsets the balance, as does the bending of the entire meniscus to correct spherical. What is necessary is one simultaneous solution for the relative powers, thicknesses, bendings, and spacings; an approach of the type described in Secs. 12.7 and 12.8 for the simultaneous solution of the third-order aberrations is ideally suited to this problem, and the automatic computer design programs make easy work of it.suited to this problem, and the automatic computer design programs make easy work of it.The double-Gauss (Biotar) (Fig. 13.14) and the Sonnar types (Fig.13.15) of objectives both make use of the thick-meniscus principle, although they differ from the preceding meniscus types in that they are used at larger apertures and smaller fields. The Biotar objective in its basic form consists of two thick negative-meniscus inner doublets and two single positive outer elements as shown in Fig. 13.14. This is an exceedingly powerful design form, and many high-performancelenses are modifications or elaborations of this type. If the vertex length is made short and the elements are strongly curved about the central stop, fairly wide fields may be covered. Conversely, a long system with flatter curves will cover a narrow field at high aperture.Common elaborations of the Biotar format include compounding the outer elements into doublets or triplets or converting the meniscusdoublets into triplets. Frequently the outer elements are split (after shifting some power from the inner crowns) in order to increase the speed. Some recent designs have advantageously broken the contact at the cemented surface, especially in the front meniscus.As indicated above, the double-Gauss (Biotar) is an extremely powerful and versatile design form. It is the basis of most normal focal length 35-mm camera lenses and is found in many applications where extremely high performance is required of a lens. It can be made into a wide-angle lens or can be modified to work at speeds in excess of f/1.0 with equal facility.。
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光电信息工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)译文：气体温度通过PECVD沉积对Si：H薄膜的结构和光电性能的影响摘要气体温度的影响（TG）在等离子体增强化学气相沉积法（PECVD）生长的薄膜的结构和光电特性：H薄膜已使用多种表征技术研究。
气体的温度被确定为制备工艺的优化、结构和光电薄膜的性能改进的一个重要参数。
薄膜的结构性能进行了研究使用原子力显微镜（AFM），傅立叶变换红外光谱（FTIR），拉曼光谱，和电子自旋共振（ESR）。
此外，光谱椭偏仪（SE），在紫外线–可见光区域的光传输的测量和电气测量被用来研究的薄膜的光学和电学性能。
它被发现在Tg的变化可以修改的表面粗糙度，非晶网络秩序，氢键模式和薄膜的密度，并最终提高光学和电学性能。
1.介绍等离子体增强化学气相沉积法（PECVD）是氢化非晶硅薄膜制备一种技术，具有广泛的实际应用的重要材料。
它是用于太阳能电池生产，在夜视系统红外探测器，和薄膜晶体管的平板显示装置。
所有这些应用都是基于其良好的电气和光学特性以及与半导体技术兼容。
然而，根据a-Si的性质，PECVD制备H薄膜需要敏感的沉积条件，如衬底温度，功率密度，气体流量和压力。
许多努力已经花在制备高品质的薄膜具有较低的缺陷密度和较高的结构稳定性的H薄膜。
众所周知，衬底温度的强烈影响的自由基扩散的生长表面上，从而导致这些自由基更容易定位在最佳生长区。
因此，衬底温度一直是研究最多的沉积参数。
至于温度参数在PECVD工艺而言，除了衬底温度，气体温度（Tg）美联储在PECVD反应室在辉光放电是定制的a-Si的性能参数：H薄膜的新工艺。
事实上，TG PECVD系统的变化可以影响等离子体的能量在辉光放电，并最终改变了薄膜的性能。
根据马丁吕，当薄膜制作接近前后颗粒的形成机制在a-Si∶H薄膜，薄膜性能对TG的相关性比衬底温度更为显著。
然而，大多数的研究到目前为止只集中在衬底温度的影响。
在我们以前的研究中，我们报道的气体温度对磷的结构演化的影响掺杂的a-Si∶H薄膜的拉曼光谱。
结果表明，存在的无定形网络逐步有序，在不久的表面和内部的Tg增加区域，导致更高质量的a-Si∶H 薄膜。
但是进一步的调查在TG的影响的结构和光电特性：H薄膜还没做好，这正是本文的目的。
在这项研究中，用不同的气体温度的PECVD沉积薄膜。
使用多种表征技术研究了薄膜的性能，包括原子力显微镜（AFM），傅立叶变换红外光谱（FTIR），拉曼光谱，电子自旋共振（ESR），光谱椭偏仪（SE），在紫外线–可见区和电气测量的光学传输的测量。
2.实验细节2.2 样品的制备用纯硅烷PECVD方法制备的a-Si:H薄膜：我们的PECVD系统配备了一个平行板电极，如图1所示:两个电极和分离的面积为220平方厘米和2厘米,分别为13.56兆赫的频率和100 MW／cm2功率密度应用于上电极和下电极接地。
PECVD系统是在一个给定的4小时在反应室达到平衡温度举行。
严格按照以下标准的程序,所有的衬底进行清洗，以确保沉积衬底和薄膜之间的附着力好之前。
在洗涤剂溶液清洗后的衬底上，立即受到酒精的超声波清洗，序列中的丙酮和去离子水10分钟。
基板被固定在样品架，上面的等离子区，避免不良大颗粒污染。
基板的热源来自上层加热单元（钨丝）的沉积过程中。
气体的热源加热带和较低的加热单元（钨丝）。
下加热单元作为保温。
值得一提的是，在我们的情况下，气体的温度是名义上的，因为它不是直接测量。
SiH4气体总流量为40 sccm（标准立方厘米每分钟）在所有的沉积。
沉积压力为60 Pa的所有样品的制备，衬底温度固定在250°C。
2.2表征方法分析了键合形成的a-Si∶H薄膜，布鲁克张量27傅立叶变换红外光谱（FTIR）装置是在室温下进行，并在环境湿度控制在一个较低的水平（相对湿度70%）。
拉曼光谱，在后向散射的几何形状，使用JYHR800光谱仪进行的，是用来对短程和中程尺度的非晶硅网络秩序的变化研究。
入射激光功率低于0.3 m W和梁的失焦的在一个直径2μm减少由于激光照射，从而提高测量精度的加热效果一圈。
ESR测量是在配备BRUKER ESP4105光谱仪双腔温度的房间里进行的，这与20兆瓦的微波功率操作相同。
原子力显微镜（SPA400）使用硅悬臂在轻敲模式图像获得。
此外，薄膜的质量密度采用浮选法测量。
在光的分析，我们认为是介电函数ε（Ε）a-Si∶H薄膜采用SE测量。
由于硒是一种间接的方法，该ε（Ε）通过使用点对se850光谱椭偏仪数据反演程序计算了样品的光谱（ψ，△），在ψ表示该偏振光平行和垂直于入射平面的反射系数的振幅比，和△是两个组件之间的相移。
为了计算ε（Ε）a-Si∶H薄膜，适当的建立光模型。
在我们的例子中，光学模型由环境/表面粗糙层/散层/衬底（K9玻璃）。
表面粗糙度层被建模为50%的a-Si 的混合物：H（或体层的a-Si）使用布鲁格曼有效介质近似（EMA）和50%的空隙。
在测量过程中，最适合采用最小均方误差函数的实现。
在紫外–可见光区域的光传输的测量使用岛津U v-1700紫外可见分光光度计进行的。
暗电导率σ（T）的薄膜，使用Keithley 4200半导体特性测试系统在V /我配置的输入阻抗大于105Ω测量。
使用especesl-02ka高低温试验箱的温度稳定性小于0.1±°C测定的暗电导率的温度依赖性。
图1 PECVD的系统结构示意图。
3.结果与讨论3.1 a-Si:H薄膜的结构特性通过AFM观察a-Si的形态特性的信息：H薄膜可以提取。
在我们的例子中，扫描是在1 M x 1 M地区μ×μ与轻敲模式进行。
在图2中，我们提出的三维原子力显微镜图像的样品沉积分别在TG的室温（RT），80°C，130°C和160°C。
这是在图2中的地形，有一个明显的趋势。
当TG是设置在RT，块的横向尺寸比其他三个样品大得多。
TG = RT的AFM 图像具有最大的表面粗糙度均方根（RMS）为3.63 nm的表面粗糙度。
顺序从1.84纳米到1.50纳米的RMS值降低，TG增加80°C ，160°C薄膜的生长要经过两个阶段的不同，岛上生长和聚结。
根据德雷维伦和同事观察，在发生合并时表面粗糙度基本不变的，薄膜继续增长时间。
因此TG修改表面粗糙度的差异归因于不同的成核位点。
ESR是其中的几个实验，给出关于缺陷[ 10 ]的结构信息。
图3给出了归一化的ESR 光谱的一阶导数：H薄膜沉积在不同的Tg。
电子自旋密度（NS）和g因子中的插图所示。
可以看出，G值的所有a-Si∶H薄膜的近2.0055。
理论计算和实验证据表明，2.0055 g值来源于悬挂键在无定形网络[ 11 ]，而不是五倍协调的硅原子，也被称为浮动债券。
如图所示，从1.1降低×NS 1017厘米−3到3.4×1016厘米−3 Tg的增加从室温到160°它表明，Tg的增加，可以减少硅的悬空键：H薄膜在很大程度上。
拉曼散射已被广泛用于估计网络结构由于其强度在固体结构紊乱敏感的演变。
在图的插图所示，矽拉曼光谱：H薄膜由几个振动模式。
在约150厘米−1带，横向声相关（TA）的振动模式，是二面角波动的密度成比例，反映了中程有序（MRO）的无定形网络[ 12 ]。
的声子的带在约ω= 480厘米−1的根均方键角变化敏感Δθ[ 13 ]。
将带向更高的频率的位置和峰宽的减少（Γ到）和短程有序的增加相一致（SRO）。
此外，一些计算的研究表明，Γ和SRO的关系可以量化。
基于连续随机网络模型，Beeman等人。
已获得的线性关系Γ= 15 + 6Δθ，这是经常使用的实验拉曼光谱测量确定Δθ[ 14 ]。
的纵向声波带的存在（LA）在300厘米−1和纵光学（LO）乐队的存在，在410厘米−1薄膜中的缺陷相关的协调，和更多的缺陷，只有/ ITO和ILO／ITO比[ 15 ]的较大的值，在那里我站对相应的振动模式的积分强度。
在ω2LA = 610厘米−1和ω2 = 960厘米−1峰是主要的a-SiωLa色彩和主要的a-Siω，分别为[ 16 ]。
在我们的例子中，拉曼数据之间的1和1000厘米600厘米−−1不分析由于色彩重叠。
a-Si：H拉曼光谱：H薄膜沉积在不同的温度如图4所示。
可以看出，所有的薄膜的研究具有典型的拉曼光谱特征，即，在约480厘米−1峰宽。
的峰值位置转移到3.61厘米−1的Tg的增加，但仍处于无序区。
另一方面，1.18厘米−1减少Γ。
这一结果表明，气体温度的增加导致的SrO a-Si的改进：H薄膜的结晶，但不。
此外，据报道，ω的转变还取决于薄膜的内在应力[ 17 ]。
根据变化的Γ，Δθ已估计定量描述SrO的变化。
图3 a-Si衍生的ESR谱：H薄膜沉积在不同的Tg，在嵌入数据对应的从上到下的TG = RT，°C 80，C 130°，和160°C.。
图4 拉曼光谱Si：H薄膜沉积在不同的温度；插图是一个典型的拉曼光谱：H薄膜及其高斯反褶积。
图2 a-Si的三维的AFM图像：H薄膜沉积在不同的Tg。
（一）RT，RMS值为3.63 nm，D = 500.26 nm；（b）80°C，RMS值为1.84 nm，D = 503.88 nm；（C）130°C，RMS值为1.69 nm，D = 525.69 nm；和（D）160°C，RMS值为1.50 nm，a 681.93 nm。
厚度d是从测量得到的。
如表1所示，有一个减少在Δθ值从6.95o到6.75o与TG的增加。
备有等人。
[ 18 ]表明，通过测量载流子寿命，它有可能涉及缺陷的a-Si的浓度的ΔθNS：H的变化。
如图5所示，Δθ和NS之间存在明显的正相关关系。
我们推测，当较大的键角发生偏差，缺陷的形成是提高稳定性和降低非晶网络的应变能量需要。
正如上面提到的，更多的缺陷，非晶网络中产生的薄膜，较大的两个ILA / ITO和ILO／ITO从拉曼测量。
然而，有趣的是，只有/ ITO的变化是在我们的实验中，对国际劳工组织/ ITO。
如表1所示，从RT TG增加到160个°C / ITO下降0.176厘米−1，国际劳工组织/ ITO增加0.144厘米−1。
上述行为异常，确切的原因目前尚不清楚，有待进一步研究。
最后，强度比ITA / ITO下降0.022厘米−1 Tg的增加从室温到160°C，这是指示性的MRO的改进。
最近，R. L. C.温克等人的计算。
[ 19 ]利用1000原子结构表明，在某种程度上，ITA / ITO取决于Δθ这与SrO，还有ITA / ITO和Δθ近似为线性关系。