侧入式发光二极管背光区域调光算法

为解决液晶显示存在能效和对比度不高问题,本文结合主流背光结构和区域调光技术优势,提出了一种侧入式LED背光区域调光算法,包括背光调光、亮度分配和像素补偿三个部分。调光算法将输入图像进行分区,计算每个分区的图像亮度;亮度分配算法引入资源分配和运输模型建立图像分区亮度到LED灯串亮度的映射关系。像素补偿算法使用低通滤波器模拟得到LED发出的光经导光板、扩散膜后的扩散效果,据此调整液晶像素亮度。并对该算法进行了大量的仿真实验,开发了原理性样机。对30幅典型图像实际测试表明,平均节能率为20.57%,平均结构相似性性能参数为0.985。本文提出的侧入式区域调光算法既能保持背光结构轻薄,同时具有较好的节能和显示效果。     

改进的S形曲线全局动态调光算法

针对S形曲线全局动态调光算法对人脸图像处理的不足,提出了一种改进的S形曲线全局动态调光算法。通过对输入图像信号进行变换,判定图像中是否存在人脸,并据此调整生成的S形曲线,对像素值进行补偿并调节背光输出。仿真结果显示,改进后的算法可以准确检出人脸图像,并有效地提升了人脸图像的显示效果。样机测试结果表明,液晶电视的图像质量有明显提升且平均能耗下降21.28%。     

Local Dimming LED TV 背光驱动整体方案研究

各个电视、液晶厂商都投入极大的物力、人力、财力加大研发力量去降低显示器的功耗,以满足大力提倡的环保节能理念。介绍一种方法主要是用于降低功率消费并提高动态对比的液晶显示技术。这种背光局部调光的方法是根据不同区域的背光的不同因素,根据图像内容相应的情况,提出一个巧妙的局部调光方案。     

ipad3拆解图全过程

新款iPad规格：苹果定制的双核A5X处理器,9.7英寸LED背光平面切换液晶显示器（2048×1536分辨率）。四核Power VR SGX MP4＋16／32／64GB闪存,背置500万像素高清摄像头。     

基于PSNR的LCD区域动态背光调节方法

动态背光对于液晶显示器降低功耗具有重要意义。考虑到在降低功耗的同时更重要的是保证显示器画面的质量,本文提出了一种液晶显示器分区域动态背光的新方法。该方法认为峰值信噪比为30是图像保质的最低标准,将失真限制在一定范围内,采用倒推法得到背光亮度。与此同时,本文提出了简化运算时间的方法,就是以区域最大灰阶亮度值的0.7倍、0.8倍和0.9倍依次搜索,直到满足RPSNR≥30就停止。为了保证图像不过于昏暗,以区域最大灰阶亮度值的0.7倍最为最小背光亮度值。该方法大幅度节约了运算时间,便于硬件实现。     

京东方32英寸LED背光源液晶电视屏试制成功

据北京市科委透露，我国大尺寸液晶电视屏关键技术研究项目已通过专家验收。京东方科技集团自主设计、应用FFS宽视角技术的32英寸LED背光源液晶电视屏试制成功，标志着我国已掌握了大尺寸液晶电视屏的关键技术，高世代生产线的技术准备更加充分。据专家介绍，采用以色彩还原好、省电优点的LED背光源，是高端液晶电视的趋势。这是国内首次应用FFS宽视角技术自主设计和试制的32英寸电视用LED背光液晶显示屏和模块，     

基于超级电容的工业仪表低功耗背光供电系统

鉴于国内外大多数工业仪表由于4~20mA环路供电的限制而不能在液晶中引入背光的现状,设计一套基于超级电容的超低功耗背光供电系统。通过对LCD供电系统的研究和实验,以超级电容作为独立电源,将电容与电池的优点结合起来。系统充电电流由单片机控制数字电位器进行,放电时则加入高效率的电荷泵,将电压升压后经恒流二极管整流驱动背光LED。最后通过实验验证该背光系统的实用性。     

LED背光模组的寿命延长技术

主要分析和介绍目前电视机的背光亮度调节技术在LED背光中的延伸实现电视机寿命延长技术,通过对LED背光亮度调节技术,充分利用LED的快速响应和数字调光的优点,同时在驱动上采用分离驱动,每三颗LED为一个单元,使相邻LED工作在不同导通状态,有效的修正因使用时间过长而带来的色坐标偏移,使LED背光产品在节能和寿命上更具有优势。     

让3D画面更完美——一套理想的大屏等离子3D家庭影院视频设备

13D的相关知识LCD液晶和PDP等离子是市场上平板电视机的两大主流技术（液晶电视机包括CCFL背光和LED背光两种,很多人把现在的LED背光源电视机与LCD电视机并列起来是错误的,特别是有些商家甚至生产厂家在这方面也有误导消费者之嫌）。     

高稳定性LED背光液晶白场仪的研究

研制了一种具有亮度监视、亮度校准、亮度补偿功能的高稳定性LED背光液晶白场仪,主要用于彩色分析仪的实验室和现场校准以及亮度色度计使用中的核查。研究了其亮度、色度、光谱、稳定性、均匀性等计量特性,并评估了LED白场仪校准彩色分析仪的测量不确定度。     

Real gas choked flow conditions at low reduced-temperatures

Real gas choked mass flux is calculated for a frictionless stream expanding isentropically until it reaches the speed of sound and without phase changes. The other parameters associated with the choked state are the pressure, density, temperature ratios, and the speed of sound. Departure of the choked mass flux from the ideal gas model is discussed first in absolute terms and then in relative terms, using the Principle of Corresponding States, for gases with boiling points in the low temperature range. Reduced-stagnation pressures are examined up to values of 30 for hydrogen, neon, nitrogen, argon, methane, krypton, xenon, and R-14 and up to 100 for ⁴He. The corresponding reduced-stagnation temperatures go down to 1.4 and in some cases down to 1.2 for nitrogen and argon. Also discussed are the limiting values of stagnation parameters for which no phase change occurs in the choked state. Compared to the ideal gas, the mass flux may almost double and the critical pressure ratio may decrease by an order of magnitude. The relevance of results is discussed qualitatively and quantitatively for Joule-Thomson cryocooling.     

As-cast microstructures and behavior at high temperature of chromium-rich cobalt-based alloys containing hafnium carbides

Hafnium is often used to improve the high temperature oxidation resistance of superalloys but not to form carbides for strengthen them against creep. In this work hafnium was added in cobalt-based alloys for verifying that HfC can be obtained in cobalt-based alloys and for characterizing their behavior at a very temperature. Three Co–25Cr–0.25 and 0.50C alloys containing 3.7 and 7.4 Hf to promote HfC carbides, and four Co–25Cr– 0 to 1C alloys for comparison (all contents in wt.%), were cast and exposed at 1200 °C for 50 h in synthetic air. The HfC carbides formed instead chromium carbides during solidification, in eutectic with matrix and as dispersed compact particles. During the stage at 1200 °C the HfC carbides did not significantly evolve, even near the oxidation front despite oxidation early become very fast and generalized. At the same time the chromium carbides present in the Co–Cr–C alloys totally disappeared in the same conditions. Such HfC-alloys potentially bring efficient and sustainable mechanical strengthening at high temperature, but their hot oxidation resistance must be significantly improved.     

Degradation behaviour of sputtered Co–Al coatings on superalloy

Degradation behaviour of sputtered Co–Al coatings on Superni-718 substrate has been investigated. Cyclic high temperature oxidation tests were conducted on uncoated and coated samples at peak temperatures of 900 °C for up to 100 thermal cycles between the peak and room temperatures. The results showed that a dense scale formed on the coated samples during thermal cycling at the peak temperature of 900 °C. The external scale exhibited good spallation resistance during cyclic oxidation testing at both temperatures. The improvement in oxide scale spallation resistance is believed to be related to the fine-grained structure of the coating. Nanostructured Co–Al coatings on Superni-718 substrate were deposited by DC/RF magnetron sputtering. FE-SEM/EDS, AFM, and XRD were used to characterize the morphology and formation of different phases in the coatings, respectively. The Co–Al coating on superalloy substrate showed better performance of cyclic high temperature oxidation resistance due to its possession of β-CoAl phase as Al reservoir and the formation of Al₂O₃ and spinel phases such as CoCr₂O₄ and CoAl₂O₄ in scale. The oxidation results confirmed an improved oxidation resistance of the Co–Al coating on superalloy as compare to bare substrate in air at 900 °C temperature up to 100 cycles.     

Capacitance based mass metering for cryogenic fluids

This paper describes a method for measuring the mass of cryogenic fluids in on-board rocket propellant tanks or ground storage tanks. Linear approximations to the Clausius-Mossotti relationship serve as the foundation for a capacitance based mass sensor, regardless of fluid density stratification or tank shape. Sensor design considerations are presented along with the experimental results for a capacitance based mass gage tested in liquid nitrogen. This test data is shown to be consistent with theory resulting in a demonstrated mass measurement accuracy of ±0.75% and a deviation from linearity of less than ±0.30% of full scale mass. Theoretical accuracies are also shown to be ±0.73% for hydrogen and ±1.39% for oxygen for a select range of pressures and temperatures.     

Equipment using a “static-analytic” method for solubility measurements in potentially hazardous binary mixtures under cryogenic temperatures

A new apparatus designed to study, at cryogenic temperatures, thermodynamic equilibria of potentially explosive binary systems such as hydrocarbon-oxygen mixtures is described herein. This equipment has an equilibrium cell which was especially designed to minimize hazards while allowing accurate phase equilibrium measurements. Reliability of results, obtained with this equipment has been verified by working on the nitrogen-propane system, for which data are already available in literature, over a large range of compositions and at various temperatures. Four isothermal curves describing liquid phase compositions at 109.98, 113.77, 119.75 and 125.63 K have been determined. Our experimental data are represented within 2% in compositions and in pressures through the Peng-Robinson equation of state implying Mathias-Copeman alpha function and Huron-Vidal mixing rule. Comparisons to literature allow pointing out: good agreement is observed with Kremer and Knapp data (1983) while the three sets of Poon and Lu data (1974) presenting systematic positive deviation are consequently judged as suspicious.     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

链结构对偏氟乙烯铁电共聚物介电性质的影响

用改进的介电松弛谱仪(精度 2‰)测定了 VDF(52)/TrFE(48)和VDF(47.5)/TrFE(47.5)/HeFP(5)在-120—140℃,10~(-2)-10~4Hz 范围的复数介电常数。介电松弛研究结果显示5mol%的 HeFP 导致三元共聚物 T_c 下降(30℃),非晶松弛强度减弱,T_g 降低(3℃),并引起局域松弛活化能升高(10.1kJ/mol),松弛时间增长。     

长余辉材料Sr_4Al_(14)O_(25)∶Eu~(2+),Nd~(3+)的溶胶凝胶法制备及性能研究

首次研究了以Nd~(3+)离子为辅助激活剂,对Eu~(2+)掺杂的发光材料Sr_4Al_(14)O_(25):Eu~(2+)余辉性能的影响.用溶胶凝胶法合成了Eu~(2+), Nd~(3+)共掺杂的Sr_4Al_(14)O_(25):Eu~(2+),Nd~(3+)发光粉末,并用扫描电镜、X射线衍射计、荧光分光光度计、余辉亮度测试仪、热释光剂量计等手段对粉末样品进行了表征.结果表明,在1350℃得到了单一的Sr_4Al_(14)O_(25)相,粉末颗粒平均粒度在1μm左右.Eu~(2+), Nd~(3+)共掺杂的Sr_4Al_(14)O_(25):Eu~(2+),Nd~(3+)发光粉末有402和485nm两个发射峰,与Eu~(2+)单掺杂的Sr_4Al_(14)O_(25):Eu~(2+)相比,发射峰位置没有变化,但适量的掺杂可以大大提高余辉时间和余辉亮度,余辉时间可达18h以上.最后通过对热释光谱的分析解释了双掺杂发光粉余辉性能增强的原因,适宜深度的陷阱可以有效存储光能,增强余辉的时间和强度.     

Development of No-Vent™ liquid hydrogen storage system for space applications

A number of technological advances required to store and maintain normal-boiling-point and densified cryogenic liquids, including liquid hydrogen, under zero boil-off conditions in-space, for long periods of time, have been developed. These technologies include (1) thermally optimized compact cryogen storage systems that reduce environmental heat leak to the lowest-temperature cryogen, which minimizes cryocooler size and input power, and (2) actively-cooled shields that surround the storage systems and intercept heat leak. The processes and tools used to develop these technologies are discussed. A zero boil-off liquid hydrogen storage system technology demonstrator for validating the actively-cooled shield technology is presented.     

Percolation and the resistive transition of the critical temperature Tc of Nb3Sn

The relationship between the distribution of the critical temperature, the percolation function, and the resistive transition of the critical temperature is explored for polycrystalline Nb₃Sn. In the neighborhood of the critical temperature, Nb₃Sn is assumed to be a random mixture of superconducting and normal grains. Percolation concepts are applied to a study of the resistivity. A general analysis is made showing that the onset and shape of the resistive transition for composite conductors are determined by the percolation function and the distribution of the critical temperature. An approximate form of the percolation function is determined based on a linear FEM analysis. Example resistive transitions are calculated for an assumed normal distribution of the critical temperature. An argument is presented that relates grain orientation and strain dependence in Nb₃Sn. It is noted that a dependence of the distribution of T_c with strain, in addition to the usual shift in T_c with strain, would be the result of a strain dependence that is a function of grain orientation. The analysis shows the extent to which the slope of the resistive transition is a measure of the distribution of the critical temperature, and therefore a measure of the grain orientation strain sensitivity. Finally, a method is described to determine the percolation function experimentally.