共查询到20条相似文献,搜索用时 203 毫秒
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不同手性剂对超扭曲向列相液晶的影响 总被引:1,自引:1,他引:0
STN-LCD在LCD显示器中占有重要地位,它价格低廉,制造工艺简单,在小型、便携式显示设备中占有重要市场。显示器显示品质与液晶材料的参数有关,研究了对于相同的液晶材料体系,使用不同的手性剂,对液晶的各项显示参数的影响和在一个母体液晶材料中,添加扭曲能力不同的手性掺加剂,对响应速度、温度系数、视角等方面的影响。按照d/p≈φ/360计算手性掺加剂用量,将不同结构手性剂加入到母体体系中,在室温时得到的阈值电压相同,测试不同温度时,DV/DT不同,响应速度变化率不同。总结了在工业生产上应如何评价和选择合适的手性剂。 相似文献
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利用数值计算方法分析了高速光电探测器的耗尽区宽度与响应度及响应速度的关系.分析结果表明,耗尽区宽度选择应在响应度和响应速度之间折中,在响应度满足使用要求的情况下,尽量提高响应速度.利用该分析结果设计了台面型InGaAs/InP pin高速光电探测器材料结构.通过优化腐蚀工艺与钝化工艺,解决了器件腐蚀形貌和钝化问题.结合其他微细加工工艺完成了器件的制备,器件光敏区直径50 μm.测试结果显示,在反向偏压为5V时,暗电流小于1 nA,电容约为0.21 pF.此外,在1 310 nm激光辐照下,器件的响应度约为0.95 A/W,-3 dB带宽超过10 GHz,其性能满足10 Gbit/s光纤通信应用要求. 相似文献
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提出了一种主回路采用峰值电流型控制、次回路采用纹波控制的新型单电感多输出降压型开关电源的设计。这种设计,使单电感多输出的控制回路变得简单,同时也使瞬态响应速度变快,交调影响和纹波变小。其开关频率为2 MHz,两路输出分别为1.8 V和1.2 V,两路负载范围为0~200 mA,实现了全负载可以正常工作。在考虑了各种寄生参数的后仿真条件下,一路负载为200 mA,一路负载从50 mA变化到200 mA,瞬态响应速度小于3μs,交调影响小于0.05 mV/mA,纹波小于30 mV,峰值效率可以达到91%。该芯片已经在CHART 0.18-μm CMOS工艺上设计实现,正在流片验证。 相似文献
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针对在矢量控制系统中普通PI控制器参数整定过程较为繁琐且性能易受电机参数影响的问题,将BP神经网络控制器应用于矢量控制系统,构造了基于BP神经网络的PI控制器,实现了PI控制器参数的在线自整定。在MATLAB/Simulink环境下进行了仿真验证,结果表明神经网络控制器较普通PI控制器具有更快的响应速度和更小的超调量。 相似文献
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文中介绍了用JALS-204定向液获得向列型夜晶垂直定向的原理和方法。文中对涂膜,烘烤,磨擦等工艺因素作了描述,并给出了预倾角,对比度,响应速度的实测数据。 相似文献
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Liu Jiangeng 《微纳电子技术》1995,(4)
介绍了吸收式电调衰减器的工作原理及电特性,在SZZ001型及SZZ002型电调衰减器基础上,又研制出调制速度极快的微波调制器,响应速度小于100ns,还给出数字控制衰减器的电特性参数。 相似文献
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《Electron Device Letters, IEEE》1983,4(6):164-166
The work presents the main peculiarities of the spectral response of back-surface-field (BSF) silicon solar cells fabricated through masked ion implantation of the n+-p junction. The emphasis is on the shift of maximum responsivity toward the visible spectrum and on the large bandwidth of these n+-p-p+ optical sensors. The dependence of these parameters on technological parameters are outlined in the communication. 相似文献
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We propose to model the spectral response of Zn(Mg)BeSe p–i–n photodetectors in order to understand their behavior and improve their performances such as maximum response and rejection rate. With this aim in view, we carry out a preliminary modeling which leads to a good agreement between theoretical and experimental results. We then develop several simulations in order to determine suitable technological and geometrical factors. We thus describe individually influences of several parameters such as the thickness of the zone exposed to radiation, the surface recombination velocity and the trap concentration. 相似文献
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Russian Microelectronics - With the reduction of the technological dimensions of transistors, the influence of the variations of circuit and technological parameters on the values of the delay of... 相似文献
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贴片是微波多芯片组件(MMCM)组装过程中的一道重要工序。由于微波多芯片组件(MMCM)正不断向小型化、高密度、高可靠、高性能、大批量方向发展,因此对贴片工序的合格率和效率提出了更高的要求。文章主要通过基于Palomar3500-III型自动贴片机进行相关试验,对影响自动贴片质量、效率的因素进行研究分析,结果表明工装夹具的设计、吸嘴设计、图像识别、程序优化、工艺参数(压力大小/保压时间、固化条件)等因素直接影响全自动贴片的成品率和效率,文中对以上几方面的优化方法及途径进行了介绍,并通过正交试验法对工艺参数进行研究,最终提出一套相对较佳的贴片参数。 相似文献
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《Microelectronics Journal》2002,33(5-6):487-494
In this paper, the switching behaviour of bulk-barrier diodes (BBDs) as a function of technological and operational parameters is studied. This study is based on the transient simulation results obtained with a 2D device simulator (S-PISCES), as well as on experimental results obtained by turn-off measurements on the fabricated structures. The results of this study show that the technological parameters (doping concentrations), as well as the geometrical sizes (middle-layer width and substrate thickness) and the bias conditions (applied voltage), have significant effects on the switching time of BBDs. The appropriate choice of these parameters can reduce the BBD switching time in the picosecond range. Finally, good agreement among theory, simulations and experimental results was achieved. 相似文献
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金刚石锯片的激光焊接工艺参数试验研究 总被引:7,自引:0,他引:7
采用800W基模CO2激光器对金刚石锯片进行了激光焊接研究。试验并研究了激光功率、焊速、离焦量及偏移量等工艺参数对金刚石锯片的激光焊接质量的影响,获得了焊接的最佳工艺参数,焊缝深宽比约为2mm,焊接熔合深度约为1.2mm。激光焊接的金刚石锯片显著地提高了其结合强度及承载能力。 相似文献
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An analytical programming model for the drain-coupling source-side injection split gate flash EEPROM
Yu-Hsiung Wang Meng-Chyi Wu Chrong-Jong Lin Wen-Ting Chu Yung-Tao Lin Wang C.S. Keh-Yung Cheng 《Electron Devices, IEEE Transactions on》2005,52(3):385-391
This paper presents a compact and accurate analytical model for evaluating the programming behaviors of the drain-coupling source-side injection (SSI) split-gate Flash memory. Starting with the bias-dependent and time-varying drain coupling ratio, a programming model is developed on the basis of the constant barrier height approximation and Lucky-electron model to express the full transient injection current, peak lateral electric field, and storage charge as functions of technological, physical, and electrical parameters. The extracted re-direction mean-free path of the SSI device is smaller than that of the channel hot-electron counterpart by one order of magnitude, which provides the physical intuition for the derived high injection efficiency of around 2/1000. The intrinsic coupling ratio depends only on technological parameters and is presented as the design index of the device. The usefulness of this model is its ability of constructing the complete operation plot of the time-to-program versus the programming voltage for various reliability windows and tunable technological parameters. Besides, the variance of the read current distribution of a memory array is also analytically predicted. 相似文献