最新刊期
期 2 ， 2009
- 摘要：The organic light-emitting devices and related materials have attracted much interest recently due to the potential of application in organic solid electric devices. The study have show that Metal-chelate can be used as luminescence materials, for example, 8-hydroxyquinoline Al has been used in OLED widely. 8-hydroxyquinoline (HQ) and Nd3+ were reacted in the alkali condition to synthesis tris-(8-hydroxyquinoline) neodymium (Ndq3 ). The electronic and crystallographic structure of Ndq3 have been studied. The structure of tris-(8-hydroxyquinoline) neodymium and the films of Ndq3 was investigated by X-ray, infrared absorption (IRA), UV-Vis and photoluminescence. From the IRA spectrum of the Ndq3, broad characteristic peak at 3 438 cm-1 corresponding to OH- stretching vibration confirmed that the Nd—O are coordinate non-ionic bond. The prominent peaks which are the characteristic of the absorption vibration of the aromatic ring skeleton at 1 602, 1 565, 1 496 and 1 461 cm-1 suggests that the conjugate action of aromatic rings in molecule is very strong and all electron orbit of quinolinic rings are π bonding hybridizations. The disagreement between IRA spectrum of Ndq3 and HQ is excellent for indicating that there is a strong coordinate action which affects O bonding heavily between Al3+ and O ions. UV absorption spectra of Ndq3 shows that Ndq3 have two peaks at 285 nm and 379 nm, optical bandwidth can be calculated to be 2.8 eV from absorption. Ndq3 thin films were prepared the by vacuum coating technology with different substrate temperatures (340 K, 360 K, 380 K), and were analyzed using XRD, the results show that Ndq3 thin film is multi crystal in structure, and the higher the substrate temperature, the larger scale of the crystal scale, and the more uniform the surface. Ndq3 emits bright fluorescence at 472 nm under ultraviolet excitation. It confirmed the existence of a fluorescent species forms between metal cation and 8-hydroxyquinolinol. The ionic radius of Nd are larger than that of Al and Zn, and its polarization force are weaker than that of Alq3 and Znq2. Thus the peaks of Alq3 and Znq2 are red-shifted compared with Ndq3.关键词：organic light-emitting-material;tris-(8-hydroxyquinoline) neodymium (Ndq3);film fabrication;characteristics
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发布时间：2020-08-12 - 摘要：The hydrogen-bonded complexes based on 4',4-bipyridine and carboxylic acids (4-propylbenzoic acid and trans-4-propylcyclohexyl carboxylic acid) assigned as PBA-BPy and PCA-BPy were prepared. Temperature-dependant FTIR was used to study the thermal stability of the complexes at the aid of DSC and polarized optical microscopy (POM). The temperature-dependant FTIR studies revealed that the hydrogen boding in complex PBA-BPy was very stable and wouldnt decompose until the temperature was higher than its clearing point; while for PCA-BPy, the hydrogen bonding decomposed at a temperature just above its melting point. That is why PBA-BPy exhibited both smectic and nematic phase while PCA-BPy showed no mesomorphic properties though with the similar structure.关键词：hydrogen bond;liquid crystal complex;temperature-dependant FTIR
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发布时间：2020-08-12 - 摘要：The dynamic behavior of hybrid alignment nematic (HAN)liquid crystals is investigated based upon the dynamic theory of liquid crystals. The equations for the director are built in three different conditions; i.e. first,backflow effect is take into account rigorously; second, the backflow is consi-dered by the effective rotational viscosity γeff; third, the backflow effect is neglected directly. Through computer simulation to the progress of switching up the voltage and switching off the vol-tage,the effect of the effective rotational viscosity γeff on the director profiles and the effective refractive index of liquid crystal was obtained.关键词：hybrid alignment nematic;backflow effect;effective rotational viscosity
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发布时间：2020-08-12
Material Physics & Chemistry
- 摘要：The electron emission experiments on PZT cathode were done under high pressure of 4×10-3 Pa and low pressure of 1.4 Pa. The number of collected electrons was given by integrating the curve line of collected current. The ratio of collected electrons under low pressure and high pressure is 0.193 3 and it can be drawn that many electrons emitted from the cathode were lost under low pressure.The reasons why electrons were lost were analyzed based on the theory of molecular motion and plasma discharge. The probability of electrons which can reach anode after collision with the gas molecular can be calculated through theory of molecular motion. The value are respectively 89.58% and 99.97% under low and high pressure, thus the ratio is 0.896 1 which is far away from the ratio calculated from collected current. Only a little fraction of the emitted electrons were lost due to the collision with the gas molecular, but more due to the plasma discharge through the grid electrode as the plasma should be considered under low pressure. The time that the grid electrode was covered by the plasma is 23.8 ns based on plasma discharge theory, which is near to the periodic time 20 ns observed from the waveforms of the collected current. Thus it can be testified that the palsma discharge is the main reason for the losing of electrons under low pressure by the above results.关键词：ferroelectric cathode;theory of molecular motion;plasma discharge
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发布时间：2020-08-12 - 摘要：A mono-domain ferroelectric liquid crystal device (FLCD) has been fabricated using an asymmetric cell, typically the combination of a polar self-assembled monolayer (SAM) for one substrate and a rubbed polyimide for the other substrate. The contrast ratio increases with the polarity of SAM. It is believed that the directions of Ps near the SAM and the rubbed substrates are same by the action of Ps and SAM, then via molecule-molecule correlation through a surface-bulk transition region, the molecule in bulk is aligned along one direction.关键词：ferroelectric liquid crystal;self-assembled monolayer;mono-domain
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发布时间：2020-08-12 - 摘要：Zirconium-doped zinc oxide (ZnO : Zr) transparent conducting thin films with high transmittance, low resistivity and good adhesion were firstly prepared on water-cooled polyethylene glycol terephthalate flexible substrates by RF magnetron sputtering. X-ray diffraction and scanning electron microscopy show that the ZnO : Zr films are polycrystalline with a hexagonal structure and a preferred orientation parallel to the substrate. The lowest resistivity obtained in our experiment is 1.55×10-3 Ω·cm. The average transmittance of the films is over 90% in the wavelength range of the visible spectrum.关键词：ZnO:Zr films;flexible substrates;magnetron sputtering;transparent conducting films
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发布时间：2020-08-12 - 摘要：In2O3 ∶ Sn (ITO) thin films were implanted by Sn+, Ag+ and Mo+ ions with diffe-rent dose of implantation and annealed in air at 250 ℃ for 1 h. The as-deposited sample and implanted ones before and after annealing were characterized by Hall measurement to investigate the dependencies of the electrical properties of ITO on the metal kind and dose of ion implantation. It is indicated that various ion implantation decrease the conductivities of ITO, while heat annealing has an opposite effect. Mo+ ion implantation supplies more carriers than Sn+ and Ag+. Sn+ ion implantation influences the mobility of ITO the least among the three kinds of ions. With a dose of 1×1015 cm-2, Mo+ implantation and the following heat annealing increase the carrier concentration of ITO by 14%.关键词：In2O3 : Sn;ion implantation;heat annealing;electrical properties
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发布时间：2020-08-12 - 摘要：Because liquid crystal molecule has anisotropic dielectric constant at liquid crystal display (LCD),the tilting angle of liquid crystal molecule changes with the loading signal voltage,leading to the changing of capacitor value . The paper uses 2DMOS simulation software to simulate the coupling capacitor Cpd which is consisted of data line and close pixel electrode, and emphatically studies the mechanism and influence trend of dielectric constant on the right and left coupling capacitor Cpd. From the simulation result, the left coupling capacitor Cpd is mostly influenced by the electric field of liquid crystal layer, the right coupling capacitor Cpd is mostly influenced by the electric field of right coupling capacitor Cpd. Due to the most part of total coupling capacitor being right coupling capacitor Cpd ,so we can decrease the value of right coupling capacitor to decrease the value of total coupling capacitor Cpd.关键词：LCD;dielectric constant;coupling capacitor
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发布时间：2020-08-12 - 摘要：The relevant parameters were designed by the volume scattering light guide plate (LGP) simulation software. According to the values of the relevant parameters, the volume scattering LGP samples were prepared. The view angle and the distribution of the output light were measured and analyzed. The results show that the output light mainly distributes in deviation from the normal of LGP at certain angle direction and a good uniformity of intensity can be achieved. In addition, the measured results are close to the simulated results.关键词：volume scattering;LGP;view angle;uniformity
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发布时间：2020-08-12 - 摘要：Four typical current programmed AM OLED pixel circuits are analyzed in this paper, and based on these circuits, compensation method of threshold voltage shift is summarized, i.e. auto-adjusting the voltage stored in the capacitor to supply a constant current. Current scaling ratio is defined, and with its increase, the current programmed AM OLED pixel circuits is improved in solving charging time of capacitor.关键词：active-matrix OLED;current programmed pixel circuit;thin-film transistor;threshold voltage shift;current scaling ratio
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发布时间：2020-08-12 - 摘要：Transparent amorphous oxide semiconductor thin film transistor (TAOS-TFT) are attracting interest for its several advantages for applications in the new generation display technology. Especially in recent years it develops rapidly. In this paper, five major advantages about TAOS-TFT are elaborated in detail by means of the contrast of traditional thin film transistors.For example, the low tempe-rature of fabrication, good homogeneity, the high mobility, the full transparency to visible light, the good performance of combination property of devices. Several crucial problems are also indicated about TAOS-TFT, such as, the in-depth study of metals component in mixed-oxide films, the further study of the influence of external environment (including bending stress, temperature, humidity, etc.) upon performance of the device, the further optimization for the preparation of the device, developing compact model with its own characteristics, and the requirements of the development and utilization of the metal element with a low crustal abundance.关键词：transparent amorphous oxide semiconductors;thin-film transistors;active matrix organic light emitting diode;active matrix electrophoretic display;compact model
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发布时间：2020-08-12
Device Technology & Physics
- 摘要：For the display drivers of portable devices, power efficiency is a key problem. This paper researched a 1X/1.5X adaptive charge pump with high efficiency. Negative feedback loop based on PAM was used to keep a constant output voltage. Furthermore, to improve charge pumps performances, several optimized design techniques were introduced. The simulation results on the basis of 0.6 μm BiCOMS technics model show: the proposed charge pump can work under 1X/1.5X mode adaptively and have an excellent performance with a higher power transform efficiency (90.8%) and lower output ripple (67 mV).关键词：adaptive charge pump;white LED driver;pulse amplitude modulation;power transform efficiency
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发布时间：2020-08-12 - 摘要：A built-in step-up and inverse charge pump for TFT-LCD driver is introduced. Based on the analysis of the charge pump, methods of optimization for the operation frequency and switchs size are proposed, as a result of which, the DC-DC conversion efficiency and power efficiency are improved. The charge pump has been simulated with a 0.18 μm high voltage mixed-voltage CMOS process. The optimization methods is proved to be effective by the simulation result. The DC-DC conversion efficiency of the charge pump can reach its best value (86.7% with load of 2 mA) at the optimized operation frequency of f=15 kHz. And the power efficiency is highest (83.6% with load of 2 mA, f=15 kHz) when the switches are employed with optimal size. The charge pump has been successfully applied to a TFT-LCD driver IC.关键词：step-up and inverse charge pump;TFT-LCD driver IC;DC-DC conversion efficiency;power efficiency
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发布时间：2020-08-12 - 摘要：A design method of how to use Sharp LQ080V3DG01 TFT-LCD module is introduced a display system of driving is designed and produced by field programmable gate array(FPGA). Driving circuit is designed in FPGA by the interface methods of LQ080V3DG01.Using FPGA to design driving circuit is succinct, the control module can be changed if the actual demand is changed.Then, the system reliability and design flexibility are improved,the problem of project can be solved quickly.关键词：LCD;Sharp;FPGA;driving
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发布时间：2020-08-12 - 摘要：The system hardware and software design of LED matrix Chinese characters display rolling screen has been introduced and the display way of 8×8 LED matrix as well as 16×16 LED matrix are analyzed deeply. System interactive simulation of hardware and software has been done on the advanced platform of Proteus ISIS, exhibiting the superexcellent function of Proteus in MCU system design.关键词：LED matrix display;Chinese characters rolling display screen;interactive simulation;Chinese font fairy
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发布时间：2020-08-12 - 摘要：OSD design of Realtek RTD series flat panel display controller products is described in detail. The addressing and accessing registers of embedded font-based OSD are the same in these products. Frame control registers, window registers and font registers can be written, by these entry address, to achieve expected on screen display function. Logo and menu design based on RTD2523B is implemented on the basis of this framework.
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发布时间：2020-08-12 - 摘要：The properties and applications of LCM240128ZK and TMS320C6713 are introduced. Based on the general-purpose input/output (GPIO), the peripheral hardware interface connectivity solution is given. In addition, the production process about the interface control timing of the DSP (Digital Signal Processors) and LCD (Liquid Crystal Display) module is elaborated. The specific software implementation are written by C language, for it is highly portable. This system can display the text, graphics and characters successfully.关键词：TMS320C6713;LCM240128ZK;liquid crystal display;interface;GPIO;C language
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发布时间：2020-08-12 - 摘要：Sometimes it may need some irregular waveforms which are used for synchronized signal in optical-fiber communications domain. This paper introduces a design method of arbitrary waveform gene-rator which can gain more precision based on multi- pulses synthesis. Moreover it also elaborates the principle of hardware system and produces the concrete hardware architecture diagram. The system works under 1G clock and carries on digital-analog conversion by AD9735. Then these data that are transmitted by PC will become 16 narrow pulses which have 0.5 ns widths and different scopes. Thus they make up of the arbitrary waveform which works in practical situation. Through lots of real experiments, it is verified that this method has better flexibility and practicability.关键词：AD9735;arbitrary waveform generator;high accuracy;multi-pulses synthesis;level transformation
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发布时间：2020-08-12 - 摘要：The performances of the short arm centrifuge test bed and its display control system were introduced. The core control chip of the short arm centrifuge test bed is the single chip microcomputer PIC16F74. By analyzing the relationship among the clock and the instructional cycle,and the demand of T6963C to single chip microcomputer, the interface method of LCD module based on T6963C controller with the PIC single chip microcomputer was obtained and applied to short arm centrifuge test bed successfully.关键词：display control system;single chip microcomputer;T6963C;LCM
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发布时间：2020-08-12
Driving & Controlling
- 摘要：A novel method of converting a 2D image to a series of parallax images was proposed. By building curve plane models based on Matlab and giving the depth information for the areas in the image, the parallax images were obtained according to the principle of depth information projection for different observing points. An auto-stereoscopic display device presents stereo images by using the parallax images. The research is beneficial to the usage of the available 2D images for auto-stereoscopic displays.关键词：auto-stereoscopic display;parallax image;transient matrix;depth matrix
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发布时间：2020-08-12 - 摘要：There is an inconsistency between real-time display and communication bandwidth in the full color LED large-scale screen synchronization display system. The image compression method with integer wavelet transform(IWT) algorithm used in this paper could greatly decrease the cost of data transmission. The IWT algorithm which only involves integer addition, subtraction and shift operation, avoids the deficiency of complicated floating-point operation in most current image compression and decompression algorithms, so it could be applied to the display screen controller to decompress image rapidly. The experiment shows that excellent image compression effect is achieved with this algorithm and only few logic elements are consumed in VLSI hardware design. At the same time, rapid image reconstruction speed meets the requirement of image real-time display in synchronization LED display screen.关键词：integer wavelet transform;image compression;LED display screen;FPGA
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发布时间：2020-08-12 - 摘要：As the wavelet-based contourlet transform provides a multi-scale and directional decomposition for images, a new image coding scheme called CSPECK was proposed, which was constructed by wavelet-based contourlet transform and set partitioning embedded block (SPECK) algorithm. In the wavelet-based contourlet transform, the high frequency sub-band decomposed by the wavelet transform was further decomposed into multiple directional sub-bands by directional filter bank so as to explain the edge and texture of the image more sparsely. The SPECK algorithm exhibits lower complexity and more efficient compression ratio. Experimental results demonstrate that the proposed method is efficient in coding images that possess mostly textures and contours. The simulation results also show that this new coding algorithm increases the PSNR by 0.2~ 0.6 dB over CSPIHT.关键词：wavelet-based contourlet;image coding;directional filter bank;PSNR
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发布时间：2020-08-12 - 摘要：The technology of solid-state true 3D volumetric display is a new 3D display technology which is based on the "Voxel"(Volumetric pixel).For the real-time display application in this technology, this paper describes a method of true 3D volumetric display data generation.Firstly,a 3D model was built by this method using Visual Studio.NET as a platform based on the OpenGL format;and then rea-ding,coding and rapidly rendering of 3D image data were studied. The programs have passed compile and debug in VC++.NET,after optimized code,it meets the requirements of the key technical indexes, and the real-time display has been realized on PC.关键词：solid-state true 3D volumetric display technology;OpenGL;3D model;optimized code;real-time display
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发布时间：2020-08-12 - 摘要：A new algorithm for eye detection in facial images was proposed. First, in a known facial image,the noises were cleaned with Median filtering method.Then, several areas where the gray-scale gra-dient was largest were chosen to be the candidates for brow- and- eye region.Finally, the exact positions,scales and directions of eyes were located by using SIFT algorithm. The experimental results demonstrated that the proposed algorithm has the advantages of higher accuracy rate and smaller computational complexity.关键词：eye detection;gray-scale gradient;SIFT algorithm
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发布时间：2020-08-12 - 摘要：A novel simplification algorithm based on vertex clustering was proposed in this paper.The simplification quality was improved by using Quadric Error Metrics to compute the placement of each clusters representative vertex. Based on the analysis for the particularity of texture mapping of cultural relic model, the appropriate mapping method was proposed,the mapping relations for geometric model and texture image was established,and the texture mapping of the three-dimensional model composed of the non-parameterized surfaces was realized.These processes enable the model photo-realistic.关键词：vertex clustering;model simplification;quadric error metrics;texture mapping
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发布时间：2020-08-12
Imaging Technology & Image Processing
- 摘要：Design solution and implement of medium size digital TFT-LCD panel test device based on FPGA are introduced. Key points and implement of hardware and software design, for driver timing generator, VCOM and Gamma reference voltage generator and PWM dimming with keys, are described in detailed. It is verified, by the timing simulation and experiment that the test device can display monocolour, gray scales,cross-talk, flicker common patterns clearly and steadily, and can meet needs in the production for the defect detection, optical performance test and analysis. It is flexible to use, and easy to transplant.关键词：liquid crystal display;FPGA;timing control;medium size;test
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发布时间：2020-08-12 - 摘要：The measurement principle and method based on the electrical measurement method for thermal resistance of high power LED are introduced. A new method of pulse measurement is presented for reference thermal resistance test based on the electrical measurement method. The method is applied to our system and delightful results are obtained. The experimental results show that the method has the advantages of good stability and exactitude.关键词：high power LED;reference thermal resistance;pulse measurement
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发布时间：2020-08-12 - 摘要：LED has inherent characteristics, such as vibration resistant, energy saving, no pollution, with luminous efficiency improving, LED application is constantly expanding, in particular,which has broad prospects in lighting.As the power of a single LED is very small, but in lighting, the uniform flux and illuminance in a certain region are required, so it is necessary to use LED array for increasing the brightness and luminous area and improving the uniformity of illuminance. The text firstly calculates LED array illuminance, and then according to formula, it makes simulation to the LED array and analyzes simulation results, which obtains the distributed characteristic of the different arrays and compares two kinds of arrays the characteristics. Finally it finds the suitable arrays to the different kinds of lamps and provides accurate reference for designing LED lamps.关键词：semiconductor light source;LED arrays;illuminance;simulation
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发布时间：2020-08-12
Test & Evaluation
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