最新刊期
期 4 ， 2011
- 摘要：Two series of bent-core liquid crystals with 1,3,4- thiadiazole as the center unit were synthesized, their liquid crystalline properties were studied by POM and DSC. It is found that both of these two serie thiadiazole compounds exhibite N phase. Among them, the symmetric five benzene ring thiadiazole ester compounds have rather high melting points, the clearing temperatures are more than 360 ℃. The melting points and clearing temperatures of the asymmetric thiadiazole molecules with allyl terminal chains are significantly reduced, and the bent-core molecule with heptyl as terminal groups shows N phase at a very wide temperature range (>120 ℃).关键词：1;3;4-thiadiazole;bent-core molecule;N phase
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发布时间：2020-08-12 - 摘要：Three types of LC materials with isothiocyanate tolane group were prepared via couple and electronation reaction. These LCs exhibit a high birefringence, and the Δn increased with conjugation length of π-electron, the maximal value among these LCs was 0.576. When these LCs were mixed in the commercial alkyne LCs respectively, the response performance of the device could be improved. These data demonstrates that the isothiocyanate tolane LCs have high Δn and low rotational viscosity,which can be used in the device of LC spatial modulator.
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发布时间：2020-08-12 - 摘要：A new synthetic method to introduce chlorine atoms in aromatic rings by using hexachloroethane is proposed in this paper. At low temperature, the lithium (potassium) reagent is made from substituted aromatics. Then, this reagent reacts with hexachloroethane to obtain chlorinated aromatic hydrocarbons with high conversion rate. In this way, the synthesis of three different intermediates, which are ortho-no-fluorine atoms substituted, one fluorine atom substituent, double fluorine atom substituent, are studied. The products are characterized by mass and element analysis. The advantages of this method are high yield, good purity and lower cost, etc.关键词：hexachloroethane;liquid crystals;chlorine-containing liquid crystals;butyl lithium
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发布时间：2020-08-12 - 摘要：A new type of side-chain liquid-crystalline polysiloxanes (SCLCPs) was synthesized by graft polymerization, using(trans,trans)-4-propyl-4'-vinyl-bicyclohexane(3HHV) with platelet texture of a blue phase as mesogenic monomer, and the production rate is 78%. The bicyclohexane structure and double bond of monomer and the hydrosilylation reaction in monomer and polymer were confirmed by characterizing the chemical structure of liquid crystal monomer and polymer by means of Fourier transform infrared spectroscopy and hydrogen-nuclear magnetic resonance spectra. Liquid crystal behavior of monomer and polymer were analyzed by differential scanning calorimetry,polarizing optical microscopy and X-ray diffraction. The mesophase temperature range of polymer was increased by 98.4 ℃ comparing with the mesophase temperature range of monomer. Meanwhile, spherulite texture of polymeric smectic A phase of liquid crystal polymer was revealed in the cooling cycle by polarizing optical microscopy, and this texture was so uncommon that can hardly be found in the liquid crystalline polymers.关键词：polysiloxanes;liquid crystalline polymers;platelet texture of a blue phase;polymeric smectic A spherulite texture
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发布时间：2020-08-12 - 摘要：The characteristics of the higher-order diffraction images of a photorefractive grating recorded in cells of homeotropically aligned nematic liquid crystal (5CB) doped with sensitizer C60 were studied. In two-beam coupling (TBC) experiments, one incident signal beam is interfered with a mutually coherent reference beam within the sample at a small incident angle and the photorefractive gratings formed. The higher-order diffraction images were observed on the screen behind the sample. It was shown that the image corresponding to the second order diffraction image which is located at the side of the signal beam is magnified, and the image corresponding to the negative first order which is located at the side of the reference beam is 180° rotated. The theoretical analyses are in good agreement with the experimental results.关键词：nematic liquid crystal;photorefractive effect;grating;diffraction image
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发布时间：2020-08-12 - 摘要：A green-emitting phosphor Sr3(PO4)2 ∶ Tb3+,Li+ was prepared by a precipitation-combustion method combined with ultrasonic-disperse technology. Photoluminescence characteristics showed that the phosphor can be efficiently excited by N-UV(379 nm) light, exhibiting four sharp unattached emission peaks located at 489, 542, 584 and 620 nm, which originate from the typical 5D4→7Fj(j=6, 5, 4, 3) transition of Tb3+. R+(R=Li, Na, K) was introduced into Sr3(PO4)2 ∶ Tb3+ as a charge compensator respectively. The results show that the incorporation of Li+ ions could induce a remarkable improvement of the emission intensity. The highest emission intensity was observed with the compound of 0.15Li+ co-doped Sr3(PO4)2 ∶ Tb3+, whose brightness was increased by 31％ in comparison with that of the Sr3(PO4)2 ∶ Tb3+. Compared with Sr3(PO4)2 ∶ 0.6Tb3+, the relatively lower emission intensity was observed when Na+/K+ was doped.关键词：Sr3(PO4)2 ∶ Tb3+;Li+;white LED;precipitation-combustion method;ultrasonic technology;luminescence property
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发布时间：2020-08-12
Material Physics & Chemistry
- 摘要：Low power consumption has been development tendency of electronic product, with popularization of LCD TV, LCD TV of the low power consumption become the pursuit of the goal of electronic products. According to the light in different position,this paper introduces the design of two 81 cm(32 in) low power LED backlight module. From key point of the structure, optical, thermals to analyze and design, the module was fabricated using 88ea 5630 LED. The test results verified that the power consumption is only 34.85 W, center brightness can reach 6 930 cd/cm2,the uniformity is over 79%关键词：backlight module;low power;LED
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发布时间：2020-08-12 - 摘要：A 118 cm(47 in) LED backlight was designed with reasonable selecting sheets and optimizing the mechanical structure. To ensure the brightness of backlight, a piece of diffusion sheet, two pieces of prism sheets and a piece of DBEF were combined. And the distance between LED and LED, the gap between LED and LGP, were determined by a series tests. Then according to the tests results, 118 cm(47 in) LED backlight sample was assembled. Comparing with other products, the module has the lowest power consumption than others with the same optical performances.关键词：low power;LED backlight;optical sheets;mechanical structure
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发布时间：2020-08-12 - 摘要：The horizontal block stripe, as an image quality defect, was analyzed by means of output signals and bias voltage stress (BVS) test. The results showed that the defect was correlated with discharging efficiency. Further, two approaches were proposed, one was to improve TFT characteristic, the other was to add reset function. The combined experiments indicated that discharging promotion can improve the defect. Especially the latter is most optimal to eliminate the phenomenon.关键词：horizontal block stripe;discharge;switch off;bias voltage stress;drain current
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发布时间：2020-08-12 - 摘要：The light guide plate is a key component of backlight units,which determines efficiency and uniformity of light emission. In view of the problem of poor uniformity and low brightness of light guide plate at present, a light guide plate was designed by the optical engineering software. A design method of the microstructure with waveform slot in the edge-lighting flat light guide plate was proposed, and distribution mode and parameters of the microstructure were designed. The results show that high-performance light guide plate could be designed when the microstructure with waveform slot distributed in the light guide plate according to regular pattern, and its uniformity is more than 80%. Compared to light guide plate with dot-matrix rectangular distributed macrostructure, whose uniformity is 60%~70%, this high-performance light guide plate uniformity increased very much. When this high-performance light guide plate size in 40 ~ 60 mm scope changes, its uniformity is more than 80%.关键词：light guide plate;waveform slot;rectangular distribution;uniformity
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发布时间：2020-08-12 - 摘要：Backlights based on white LEDs have significant advantages for liquid crystal display(LCD) such as good optical property, low power dissipation, long lifetime, high contrast, simple drive system and so on. However, not all LEDs are suitable for light source of backlights.The influence of liquid panel and different white LEDs on color gamut are investigated. Results showed that, to obtain high color gamut, LCD pannel and the corresponding LED light source are needed. Due to the mixed crest, 2-band LEDs which used for illumination only achieved 75.2% NTSC gamut. Then for 3-band LEDs, as its crests are independent relatively, it could obtained 84.2% color gamut.关键词：LED backlight;white LEDs;TV color gamut
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发布时间：2020-08-12 - 摘要：Some factors of CCFL LCD TV were discussed in this paper, such as mixing height, reflective film edges, the lamp quantity and distance between the lamp, the distance of lamp away from the reflective film,and the type of diffusion plate which affect optical efficiency and optical effect of LCD TV. Based on the 119.4 cm(47 in) CCFL LCD TV, a set of optimal mechanical optical parameters was simulated using Optisworks Plugin of Solidworks, and the samples had been fabricated according to these parameters, the corresponding parameters of the samples had been tested.关键词：power consumption;CCFL LCD;mechanical and optical structure
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发布时间：2020-08-12 - 摘要：The patterned Si nanowire arrays have been successfully fabricated by combining photolithography and metal-assisted Si chemical etching.The morphologies of the arrays are characterized by scanning electron microscopy (SEM). The experimental results reveal that field electron emission from the arrays can be obtained. The patterned Si nanowire arrays is beneficial to patterned electron beams with a low divergence angle. The investigation results provided an efficient way to fabricate the patterned Si nanowire arrays electron sources for various vacuum microelectron devices with some advantages such as, simple process and suitable for IC technology.关键词：patterned Si nanowire arrays;metal-assisted Si chemical etching;field emission
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发布时间：2020-08-12 - 摘要：This paper investigated a high efficiency stacked white fluorescent organic light-emitting diodes consisting of separate blue and yellow elements with a 1,4,5,8,9,11-hexaazatriphenylene-hexacar bonitril (HAT-CN) hole injection layer. The configurations of the devices are ITO/2-TNATA or HAT-CN(x nm)/NPB (25 nm)/ADN (30 nm) ∶ TBPE (2%) ∶ DCJTB(1%)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm). According to the experimental result, the effect of HAT-CN film on carrier injection and color purity were significant. This work obtained a higher efficiency and color purity for the WOLED with HAT-CN layer, as compared to the conventional devices with copper phthalocyanine (CuPc) or 2-TNATA materials as a hole injection layer. It shows pure-white light emitting with 1931 CIE chromaticity coordinates x=0.330 9, y=0.347 2, and a current efficiency of 6.4 cd/A.关键词：HAT-CN;WOLED;electrical properties;optical properties
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发布时间：2020-08-12 - 摘要：A novel anode structure of organic light-emitting diodes was fabricated by inserting a molybdenum trioxide (MoO3) layer into the interface of hole injection layer(HIL) 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) and hole transport layer 4,4'-bis biphenyl (NPB). The microcavity OLED with a 150 nm-thick Al top cathode and a transparent Al bottom anode on a glass substrate was fabricated. It has the configuration of Glass/Al(15 nm)/HAT-CN(10 nm)/MoO3 (x nm)/NPB(30 nm)/Alq3 (70 nm)/LiF (1 nm)/Al(150 nm).The current density-voltage-luminance(J-V-L) performances shows that this structure is beneficial to the reduction of the driving voltage and the enhancement of the luminance. The highest luminance of the device is reached to 14 390 cd/m2 at 13 V, with a turn-on voltage of 3.4 V. "Hole only"devices were fabricated to verify the enhancement of hole injection and transport properties of this structure. The optical characteristics of the microcavity, such as narrowed and peak shift, were examined.关键词：OLEDs;double HIL;microcavity
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发布时间：2020-08-12
Device Technology & Physics
- 摘要：This paper gives a main structure of the display-control terminal equipment, and shows the function of virtual oscillograph and virtual meter by dynamic pictures switching and waves moving, which is based on programming of DSP. After the experiments on the vehicle, this system goes well and shows good performance of human-computer interaction.
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发布时间：2020-08-12 - 摘要：The design of high speed digital video storage system based on 64-bit operation system is discussed because ultra high frame-rate and high pixel number digital cameras are widely used in the field of optical measurement. This system uses high performance PC as hardware platform and high capacity memory is carried. The software puts image and appendix data into cache in memory during the storage process and after the process the software writes the data into hard disks array. The choke point in unstability of data transfer speed of the increasing number of hard disks is overcomed. According to application the bandwidth can exceed 800 Mbyte/s and the expected result is obtained.关键词：64-bit operation system;high-speed camera;photo-electrical theodolite;digital dideo storage
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发布时间：2020-08-12 - 摘要：Drawing system design example based on graphical liquid display controller T6963C is given with Proteus as design platform. The author analyzes the core subprogram of plotting dot seriously and deals with the subprograms of typical graphics drawing in detail. The system program writing and debugging are performed in Keilμvision3 and the system software and hardware interactive simulation is performed in Proteus ISIS. Finally, the author performed the actual circuit connection and realized the system function.关键词：liquid drawing;graphical liquid display controller T6963C;Proteus simulation
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发布时间：2020-08-12 - 摘要：Using LCD module embedded microcontroller and mechanically contacted metal keyboard, a kind of man-machine interactive system for aerial mapping camera was designed. Based on the mode of DSP cooperating with FPGA, the interfaces of hardware and software are realized for LCD module and keyboard. The task requirement, the construction thought and the questions considered emphatically are described in detail. The cause that 'snow’ phenomena of LCD is analyzed and the resolution is presented. Furthermore, the design of custom character library is introduced. The experiments on ground and in air show that the system is reliable, and its visibility and operability are satisfying. The requirements for system are achieved, and it provides a kind of referenced design concept for other man-machine interactive system.关键词：aerial mapping camera;man-machine interactive system;RA8835 controller;FPGA;TMS320F2812
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发布时间：2020-08-12 - 摘要：To meet the requirement of the especial sequence IR camera signal being captured by the general CameraLink imaging acquisition card, the sequence adjustment and interface transforming system based on FPGA was designed. The SignaTap tool was applied to measure the detailed sequence of the IR camera output and based on which the sequence adjustment system was designed according to the sequence requirement of the imaging acquisition card. The FIFO module in FPGA was applied to realize the pixel clock modification and the data saving and taking. The Verilog programming was applied to realize the pick-up of the valid signal, the cut-off of the invalid signal and the modification of the line valid and frame valid signal. The camera especial sequence adjustment system adjusted the especial sequence to the sequence that can be identified by the common CameraLink imaging acquisition card.The experiment shows that the processed image signal can be captured by the imaging acquisition card and the displayed image is correct and stable.关键词：sequence adjustment;FPGA;image display
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发布时间：2020-08-12 - 摘要：To reduce portable devices with embedded systems power consumption, AMOLED display scheme is implemented,it has the advantage of fast reaction speed, high contrast, wide viewing angle, thin and low power consumption.Driver circuit is designed for CMEL(CHI MEI EL Corporation) C0240QGFA-T.Linux driver is designed for the driver circuit based on Sumsung’s ARM9 processor S3C2440A. The test result indicates that the scheme is feasible and the board could display with high quality.关键词：embedded system;Linux;AMOLED;driver;S3C2440A
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发布时间：2020-08-12 - 摘要：A multi-channel OLED stress test system was designed and made. The system could simultaneously stress 512 OLED devices independently in constant current, constant voltage, or constant light intensity testing mode. The system has a wide range of testing conditions with output current from 0.02 mA to 100 mA, and output voltage from 0 to 24 V. The system adopts a modular design which could easily build 512, 256, 128, 64, 32 channels based on users needs. The application software built on LabVIEW development platform includes a user-friendly interface, and a self-protection feature from power failure, ensuring the continuity of the testing, and the safety of the data. With an environment chamber, the ambient temperature and humidity could be conveniently adjusted.关键词：OLED;lifetime;multi-channel;Labview;stress test
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发布时间：2020-08-12 - 摘要：Considering narrow temperature and viewpoint of LCD for most portable display system, OLED is used as display device. Focusing on the problem of low contrast of generic driver method for portable display system, a new driver based on FPGA is introduced which can improve the flexibility of the system. As the MCU, PIC16F690 takes control of system sequence. While FPGA mainly handles video processing work, including color standard converting, color gamut dealing, interlaced video to progressive video. Results show that the contrast is improved dramatically, images displayed stably. The design provides a platform for future.关键词：OLED;FPGA;PIC
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发布时间：2020-08-12
Driving & Controlling
- 摘要：In order to design a moving target fast tracking system with respect to a time-limited and stable tracking process, specially when the shape of moving objective or its environment condition change, a new approach named SURF-KMs which combines the advantage of SURF algorithm with a cluster analysis of K-means method is proposed. First, based on SURF algorithm, interest points and vectors are presented. Second, using K-means method, we can estimate the target-center, determine target’s cluster scope and update the tracking window online. Finally, a self-adapting updating strategy for matching template is also proposed in order to track moving target automatically. Experimental results indicate that SURF-KMs is mostly able to achieve a stable tracking while the monitored target rotating, scale changing, and also the environment illumination glittering. Moreover, it can satisfy the system requirements of tracking stability, higher precision and anti-jamming.关键词：SURF;cluster;moving target;fast tracking
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发布时间：2020-08-12 - 摘要：When compressing image of high bit-wide infrared cameras to 8-bit analog image to display, it exists that image lost the most details, this paper put forward a new algorithm that use the Gauss filter to make the image still to keep the infrared image detail information after compression. The paper introduced the method how to make algorithm to be realized on FPGA hardware,and make an experiment that 12 bit camera image is compressed to 8 bit analog display on real-time. The experimental results show that the system can keep the detail information perfectly under the condition of restrain noise,and can change 12 bit-wide 320×240 surface array of infrared cameras into analog video under preserving details.关键词：DDE;image compression;FPGA;infrared video
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发布时间：2020-08-12 - 摘要：In order to further improve the accuracy and real-time performance of small infrared target detection, a new improved method is proposed. First, aiming at the characters of the infrared image, the improved Top-Hat filter is used to restrain background for the purpose of increasing the target detection probability. Second, the bound set is constructed to limit the gray level histogram to region of interest for reducing the interference of background and noise. Then target detection is achieved by image segmentation using improved OTSU algorithm. Furthermore, the fast recurring algorithm is applied to proposed algorithm for accelerating the running speed of the segmentation algorithm. Different types of infrared images are selected to compare the results of purposed algorithm and the other two algorithms in references. Experiment results show that proposed algorithm has better performance than the other two markedly. Object segmentation is more accurate and running speed is accelerated by more than 60%. Finally, the bound histogram can be constructed aiming at concrete problem, based on gained prior knowledge, so it has better generality.关键词：infrared small target detection;improved To-Hat;2D bound histogram;improved OTSU algorithm;image segmentation
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发布时间：2020-08-12 - 摘要：The cell gap measurement system of LCD was designed using FPGA as the core chip, in which the image of lights interferences stripe was obtained by using CCD. And it was optimized by the Canny algorithm. It was found that the system has many advantages such as less error, simple structure and easy to run. As a result, the system can be used as on-line automatic measurement system of LCD cell gap, and the relative standard deviation of it can be increased to more than 0.02%, which implies that the system can be used in the monitoring of LCD cell gap.关键词：Canny algorithm;liquid crystal cell gap;gray processing;FPGA
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发布时间：2020-08-12
Imaging Technology & Image Processing
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