最新刊期
期 6 ， 2010
- 摘要：Based on the Erickson-Leslie continuum theory, the hybrid aligned nematic in-plane switching (HAN-IPS) liquid crystal cell is investigated with considering the backflow effect. The relation of liquid crystal director and flow velocity is obtained under the condition of strong surface anchoring. The results of computer simulation show that the backflow effect speeds up achieving equilibrium state and breaks the symmetry of the director configuration. The phenomenon is very obvious especially in the initial milliseconds after switching on the applied voltage.关键词：hybrid aligned nematic;in-plane switching;backflow effect;distribution of director
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发布时间：2020-08-12 - 摘要：The stress state and its effect on optical properties of GaN films grown on porous SiNx interlayers by using metal organic chemical vapor deposition (MOCVD)method are investigated. The stress is characterized by the frequency shift based on micro-Raman spectroscopy measurement. It shows that more residual stress in GaN film grown on the SiNx interlayers is relaxed when the time of in situ SiNx deposition is increased. Accordingly, the donor bound extion(DBE) peak shows red shift in low temperature photoluminescence(PL) measurement. We assume that the increasing time of in situ SiNx deposition enlarging the lateral overgrowth area is the main reason to reduce the residual stress and influence corresponding optical properties.关键词：GaN;MOCVD;stress;porous SiNx interlayers
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发布时间：2020-08-12 - 摘要：Hexagonal cone-shaped ZnO nanomaterial were synthesized by the esterification with zinc acetate and ammonia water. By the test methods of XRD and SEM etc.,the preparation condition, field emission performance and stability of nanometer zinc oxide thin film were studied.The experimental results indicated that the pyramidal nanometer zinc oxide prepared by hydrothermal method has the good field emission performance, and is the ideal material for FED negative pole.关键词：ZnO nanomaterial;cone-shaped;hydrothermal method;field emission performance
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发布时间：2020-08-12 - 摘要：The lateral difluoro-diphenyltolane compounds (Ⅵ) with low viscosity, high birefringence were synthesized. Their structures were determined by IR, 1H-NMR, 13C-NMR, 19F-NMR and MS. The transition temperature of liquid crystal phase and phase states were measured by DSC and POM. Their birefringence and viscosities at different temperature were also tested and analyzed. Experimental results show that the compounds synthesized exhibit high birefringence (Δn≈0.32), have lower viscosities and smaller temperature dependence at low temperature,comparing with the other relative structure of tolane compounds. These compounds are particularly attractive for reducing the viscosity of liquid crystal materials and achieving fast response times in LCD.关键词：alkyl lateral difluoro-diphenyltolane compounds;synthesis;low viscosity at low temperature;high birefringence
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发布时间：2020-08-12
Material Physics & Chemistry
- 摘要：Aluminum nitride (AlN) thin films were prepared by radio frequency (RF) reactive magnetron sputtering at the pressure ranging from 0.5 Pa to 2.0 Pa. Keeping the invariant process parameters, the thickness of the films changed very small by changing the working pressure. The field emission (FE) measurement showed that the FE current can be observed only for these films prepared under the lower work pressure 0.5 Pa and 0.7 Pa. The scanning electron microscope (SEM) images showed that the films prepared with higher working pressure (2.0 Pa) are easy to form vacancy and micro-voids. Then electrons transport in the films will be scattered by the defects and cant tunneling through surface barrier and no FE appearing. It suggests that for AlN films prepared by RF reactive magnetron sputtering, to get excellent FE properties, a lower pressure may be better. The study also indicates that the films with more compact grains and smaller defects may have excellent FE properties.关键词：AlN films;field emission;working pressure;defects
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发布时间：2020-08-12 - 摘要：TEA CO2 laser can generate great electromagnetic interference (EMI) during its operation which makes LCD data disorder and even no display. The measurements and analysis are conducted for EMI and LCD module in this paper. Through electromagnetic screen for LCD module and display area, insulating and filtering for supply source, suitable shorten for data cable, EMC of laser to LCD module is effectively suppressed. The experimental results show that the capability of the designed screen in all EMI frequency bands can satisfy the requirement which the effectiveness of shielding is 56.2 dB in 34 MHz. There is not EMI for supply source and LCD module can show data stably. The results show that using EMC reinforcements for conducted and radiated interference can make LCD module work stably and reliably in the environment of intense EMI.
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发布时间：2020-08-12 - 摘要：Banana-shaped compound 1,3-phenylene bis(4-butyloxy-benzylideneamine) was synthesized. Using the analytical methods of nuclear magnetic resonence, ultraviolet-visible spectroscopy,mass spectroscopy, polarized optical microscopy, differential scanning calori-metry and laser light diffraction experiment, the synthesized banana-shaped liquid crystal material was characterized in detail. The results demonstrated that the banana-shaped liquid crystal molecules were able to assemble themselves into organic groove-free gratings which could be diversiform defined structures with a periodic modulation of the birefringence index. Despite the gratings were groove-free, helium-neon laser diffraction experiment showed that the self-organized optical gratings by the banana-shaped liquid crystal molecules exhibited the same diffraction patterns as classically ruled gratings.关键词：banana-shaped liquid crystals;self-assembly;groove-free gratings;diffraction pattern
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发布时间：2020-08-12 - 摘要：For the projected-capacitive touch screen, the key issue is to improve reliability and reduce cost by a very robust and reliable sensing circuitry, appropriate sensing layer patterns and corresponding algorithms. This paper presents a design scheme of capacitive touch sen-sing system based on the principle of relaxation oscillation, and uses the program on the projected-capacitive touch screens to test capacitance and analyze data to provide the basis to open up a single point or multi-point touch method.关键词：relaxation oscillations;projected-capacitive;touch sensor;reliability
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发布时间：2020-08-12 - 摘要：The basic principles and characteristics of capacitive touch screen were introduced. The touch-screen data processing algorithms were researched and one method was presented about the pixel mapping between capacitive touch screen and LCD. The edge error problem of the capacitive touch screen system was solved by coordinate correction and the edge com pensation parameters. Software test results show that a good user experience has been achieved.关键词：capacitive touch screen;pixel mapping;edge error
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发布时间：2020-08-12 -
Optimization and Design of Micro-Groove Structure of LCD Light Guide Plate Based on Freeform Surface
摘要：Based on the demand of high-brightness, uniform luminance and ultra-thin structure of LCD backlight module, a new combination design method of light guide plate is proposed for LCD edge backlight module in this paper. Specifically, when an ideal Lambertian light propagated into the incident surface of light guide plate, a micro-groove structure based on freeform surface function for light guide plate was proposed and determined for satisfying the requirement of uniform luminance. Further, the light guide plate based on the proposed micro-groove structure is modeled and simulated by using optical software TracePro. Experimental results show that this micro-groove structure can provide good uniform luminance by setting particular property of optical coating film and reflector, which also meet the requirement of ultra-thin structure.关键词：light guide plate;backlight module;LCD;micro-groove;free-form surface- 36
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发布时间：2020-08-12 - 摘要：The light extraction plays an important role in LED encapsulation to obtain a high efficiency. The influence of package structure on LED light extraction was investigated by the TracePro simulation in this work.The results indicate that cavity shape almost have no effect on light extraction,ratio of light-out depends on the flare angle of cavity and salient of top surface, additionally, ratio of light-out is related to the height, reflectance and bus of a certain cavity. Overall, the structure of package truly affect the LED light extraction, hence package structure plays a significant role in packaging LED with high light extraction.关键词：LED;encapsulation structure;light extraction
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发布时间：2020-08-12
Device Technology & Physics
- 摘要：The control method of real-time display by MCU was given with DC LCD digital voltmeter as an example and LCD controller as control object. The system circuit and program were designed combining with EDA simulation tools Proteus and system interactive simulation was performed on Proteus, realizing the correct display effect of dynamic data. The reason of error generated was analyzed and the nature of real-time data display control was summarized.关键词：LCD;real-time data;T6963C controller;Proteus simulation
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发布时间：2020-08-12 - 摘要：Aimed at the problem of the embedded multi-channel video acquisition and display system, a new one based on FPGA is put forward. The configuration of the system is given. The principle and key issue are analyzed. Using the status shift mechanism, the protocol of I2C is realized and the controlling time sequence signals of TFT-LCD are produced. The synchronization among multi-channel video acquisition is achieved by using time-division multiplexing technology. The problem of conflict between reading and writing frame cache is solved through the two SRAM switch. The frame composition technology is applied to accomplishing the change from interlaced scanning to progressive scanning. The result of project application shows the virtues of system, such as good effect of acquisition and display, low cost and low power consumption.关键词：multi-channel video acquisition and display;status shift mechanism;time-division multiplexing technology;two SRAM switch;frame composition
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发布时间：2020-08-12 - 摘要：By studying and analyzing the functional properties of Embedded Microprocessor Unit of LPC2378 and OCM12864-1 LCD module, a LCD menu display system based on LPC2378 system board has been constructed. Both the interface circuit and program design methods between the LPC2378 and the LCD module are discussed. The timing compatibility problem between high speed ARM processor and slow speed LCD model is solved and the initialization procedures are provided. This design has been proved feasible according to the actual operation.关键词：LPC2378;OCM12864-1;menu;interface
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发布时间：2020-08-12 - 摘要：LCD and matrix keyboard are used usually in embedded systems for the intercourse between the user and the machine. In this paper, a 192×64 LCD is used as the monitor, two ZigBee nodes are used for wireless control, and a matrix keyboard is used to connect with the LCD module through which the user can send command to the control system. The LCD module can display Chinese and English characters together, homochromous bitmaps, and objects in reverse. The measured maximum distance can reach to 50 m and stable communication can be realized within 20 m. This man-machine interface can be used in wireless meter reading system, numeric control system, etc.关键词：ZigBee;man-machine interface;liquid crystal;wireless control system
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发布时间：2020-08-12 - 摘要：This paper summarized the design process of a control panel, which is based on ATmega1280 AVR chip microcomputer and constitutive of a LCD module and a keyboard module. In this design, a LG3202405 LCD module controlled by RA8835 was used as the display device, and a 6×4 matrix was used as the input device. According to the design of hardware connection between EPM7128 and the chip microcomputer, the LCD module and the keyboard module shared the I/O port resources of the chip microcomputer.关键词：ATmega1280;RA8835;matrix keyboard;I/O ports sharing
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发布时间：2020-08-12 - 摘要：In order to solve the problem of FPGA configuration failure when the satellite camera is power-on, a FPGA configuration process monitoring system was designed. First, the process and principle of FPGA configuration were analyzed in detail. Then, this paper described the core monitoring circuit in the FPGA configuration monitoring system, the design ideas of software for the monitoring system, code implementation and simulation procedures for monitoring FPGA configuration. Finally, the experiment data were processed by MATLAB software, and thus FPGA device configuration failure rate and failure rate curve were obtained to verify the feasibility and superiority of the design. Experiment results indicate that by using the system the success rate of FPGA configuration is up to 100%. Compared with the traditional methods of FPGA configuration, the new design made configuration success rate increased by 0.041%,can satisfy the satellite cameras requirements of high success rate and reliability of configuring the FPGA application. This scheme has been applied to the development of a certain space camera. The application results show that the FPGA configuration monitoring system can monitor timely exception which occurs in the process of FPGA configuration and can analyze the error origins and can configure successfully the FPGA applications when the satellite camera is one-time power-on.关键词：FPGA configuration;monitor state machine;watchdog timer;virtual model;MATLAB
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发布时间：2020-08-12 - 摘要：Based on the structures and characteristics of AM-OLED, a design program of AM-OLED interface circuit for SVGA050 microdisplay chip is presented using PIC18LF2550-based controller. By the master of the I2C serial bus configuration registers of each module parameters, VGA and CVBS video input information is correctly displayed on the AM-OLED. The development of the hardware system measurement verified the effectiveness of the program.关键词：OLED;test system;video interface;PIC18F2550
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发布时间：2020-08-12
Driving & Controlling
- 摘要：The actual auto-focusing devices in airborne image equipment have the problem of complexity in design and unable to integrate. In order to solve this problem, the application of image based on auto-focusing method in airborne image equipment was presented. Accor-ding to that the gradient edges in normal images are more than horizontal and vertical edges, a new focus measure method (Lean operator) derived from gradient edge detection was proposed. Series of experiments were committed to have the Lean method compared with the other several kinds of auto-focusing method. According to the experiment results, the Lean operator and correlation operator were respectively chosen as the focus measure method of coarse search and fine search. Then, local full search (LFS) strategy and change step hill-climb search (CHS) strategy were proposed in allusion to the feature of focus measure function of airborne image equipment. When using a lens of 130 steps focus length and 2 steps focus depth, the LFS and CHS search strategy can respectively cut the total focus time from the full searchs 43 s to 7 s and 5～8 s. The results show that the correlation operator with the cooperation of the lean operator can locate the prime focus position accurately,the accuracy is over 95%.关键词：airborne image equipment;focus measure function;image lean edge detection;search strategy;local full search;hill-climb search
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发布时间：2020-08-12 - 摘要：To test the tracking performance of optical measurement device,this paper discusses a method which is based on Visual C ++ and Multigen Vega environment to develop a virtual reality simulation system,and elaborates development process. The simulation models of the cargo projectile is established with MultiGen Creator. According to the particular model of Shrapnel ejection, a particle system to simulate the process of Shrapnel ejecting is defined.The flight attitude and flight speed of the bullets and mother bombs are updated in real-time when the shrapnel triggers the ejection event in the scheduled throw-point.Simulation models are driven by MultiGen Vega. Special effects are added to the simulation to enhances the infectious and authenticity of the simulation environment.The parameters of simulation system can be easily modified and the simulation results are shown directly, these make the tracking effects evaluation of optical measurement device easily.关键词：virtual reality;Shrapnel ejection;VEGA;particle system
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发布时间：2020-08-12 - 摘要：The traditional projection onto the convex sets super-resolution image reconstruction algorithm leads to the blur edge of reconstructed high resolution image. Based on the traditional algorithm, a method based on gradient interpolation is proposed, which is used to generate the initial estimation of the super-resolution image. Furthermore, by modifying the point spread function(PSF), the center of which is on the edge, the coefficients along the direction of big gradient are reduced, while others keep constant. We reconstruct a set of low resolution images with the updating algorithm. The experimental results show that the edges kept very well, and the performance of the reconstructed images is improved.关键词：super-resolution;projection to convex sets (POCS);point spread function(PSF);edge constraint;Canny;aerial photography
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发布时间：2020-08-12 - 摘要：In a camera system of CCD as sensor and utilizing CCD video signal integrated processor (video signal processor for short), when gain is high, the black level auto-correction process of video signal processor will cause CCD image gray value vary slowly and sharply at the beginning stage with target brightness not varying. Based on XRD98L59 of EXAR, this paper analyzes the device structure and its black level auto-correction process, establishes the model of black level auto-correction process, determines the parameters by experiment, and verifies the correctness of the model. According to the calculating results of the model, the preparing time of the camera system is adjusted to 5 s, the problem that CCD image gray values vary "slowly" and "sharply" at the beginning stage is resolved.关键词：CCD;video signal processor;black level;auto-correction
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发布时间：2020-08-12 - 摘要：This paper presented an image stitching algorithm of small view-of-field(VOF) retinal micro blood vessel grabbed with liquid crystal human eye aberration correction system. After improving the traditional Harris characteristic angle method, the following disadvantages were avoided for processing low contrast and small VOF retinal blood vessel: poor positioning precision, cubic Gauss flattening, relatively large calculation quantities, and sensitive to noise. With the presented method, the retinal micro blood vessel can be stitched fast and accurately, which increases the observation field to large extent and provides more accurate information for doctors.关键词：retina;image stitching;human eye aberration correction
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发布时间：2020-08-12 - 摘要：After various arithmetics of tracking are researched, a better adaptability multi-template tracking arithmetic based on template self-correlation is presented in this paper, and a new distilling template algorithm of replacing temple guide line, object occlusion judgment guide line and etc are provided. Experiment results show that this tracking arithmetic can track the object stably even if the moving object has occlusion in clutter background.关键词：temple matching;correlation tracking;occlusion
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发布时间：2020-08-12 - 摘要：In order to improve the accuracy and real-time performance of the non-contact measurement, a real-time two-dimensional correlation speed measurement was proposed on image processing using high speed CMOS based on FPGA. The principle and practical work method of the measurement were analyzed, the range and accuracy of this two-dimensional correlation speed measurement were deduced .The resolving power of the CMOS image sensor is one pixel, and it can be improved to 1/8 pixel by Subdivision Technology. The mathematical operation is converted to logical operation through FPGA .Finally,a preliminary test result is presented.关键词：CMOS;correlation speed measurement;two-dimension;FPGA
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发布时间：2020-08-12 - 摘要：Sea-sky-line detection is an important component involved in the target tracking under the condition of sea-sky background. Considering the diversity of the sea-sky background, this paper first analyzes the disadvantages of some existing algorithms, and then a better adaptability sea-sky-line extraction algorithm is presented. First, median filter is used to eliminate noise such as cloud and sea clutter and other noise, and then Hough transform based on phase grouping is used to extract the sea-sky-line. As the algorithm combines the advantages of both the phase grouping and the Hough transform, it can not only extract the sea-sky-line under low-contract, but also has strong anti-interference, and overcome its own shortcomings of phase grouping and Hough transform. The experimental results show that the method can extract the sea-sky-line from the simple and complex background. Through lots of experiments, the results proved that this algorithm is adaptability, robustness, accurate positioning, reducing the complexity of the follow-up target tracking.关键词：sea-sky-line;Hough transform;phase grouping;median filter
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发布时间：2020-08-12 - 摘要：For the image processing system consisting of the image grabbing card and computer, a software is developed to grab and display images of the CCD camera system. In the software, the modulations are calculated, which are the indicators for evaluating the general image quality of the CCD camera system. This design takes full advantage of Matrox imaging library for secondary development. The software can display, save and calculate the modulations of output images by invoking functions of Matrox imaging library with VC ++ 6.0. To improve the software performance, the main algorithm is optimized. Lab tests show that the software can display and process the output images in real-time. The calculated modulations are accurate and the software operates stably. Using the function library of the image grabbing card to develop image displaying and processing software, development cycle can be shorten and the reliability of the software can be improved.关键词：image grabbing card;Matrox imaging library;contrast transfer function;VC ++
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发布时间：2020-08-12 - 摘要：This article introduces a new type image grabber and processor based on Camera Link. The system can grab the digital camera image data, then process it at real-time. As the main processors of the system, the FPGA accomplishes the test of images grabbing and pro-processing, the DSP accomplishes the test of more complex images processing. The design about the processors structure is described in detail and some key technologies are introduced, such as Camera Link interface technology, cache memory and display technology, image process and output interface technology, et al. The system can reach 1 000 frames/s for real-time image grabbing and processing after the system has been debugged.关键词：camera link;image acquisition;image process
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发布时间：2020-08-12 - 摘要：One-dimension slit barrier for flat-panel 3D(three-dimension) display has some advantages of low cost and changing parameters easily and no need to focus, but it has a little lower brightness because of blocking light. Two-dimension lens array has the advantages of full parallax and natural depth perception, but its viewing-resolution and viewing-angle are limited. In order to combine the advantages of the above-mentioned two kinds of scheme, a new flat-panel 3D display scheme based on 2D(two-dimension) square hole barrier is proposed according to one-dimension slit barrier technology and two-dimension lens array scheme in the paper. The results of simulating experiment of Lighttools indicate that the image quality factor of 2D square hole barrier is slightly less than one-dimension slit barriers, but it has the advantages of one-dimension slit barrier technology and two-dimension lens array, and it is a new direction of development for flat-panel 3D display.关键词：flat-panel 3D display;longitudinal and horizontal parallax;image quality factor
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发布时间：2020-08-12
Imaging Technology & Image Processing
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