A high efficacy and tunable white light-emitting diode cluster with both color fidelity and nonvisual performances close to natural lights

A luminous efficacy model for a white light-emitting diode (LED) cluster was developed, and five α-opic efficacy ratios (γ_α,Vs) of intrinsically photosensitive retinal ganglion cells were adopted in order to quantify its nonvisual performance relative to natural light. A tunable C/A/R LED cluster, which consists of the cyan LEDs with green phosphor excited by a blue LED, the amber LEDs with green and orange phosphors excited by same blue chip, and the red LEDs, was proposed by maximizing the average luminous efficacy at correlated color temperatures (CCTs) of 2700 to 6500 K under the condition of color fidelity index (R_f) above 96 and five values of γ_α,V of 0.95 to 1.05. The real tunable C/A/R LED cluster with a R_f of 95 to 96, five values of γ_α,V of 0.97 to 1.01, and a luminous efficacy of 114 to 120 lm/W at a CCT of 2670 to 6456 K were demonstrated. Furthermore, five values of γ_α,V can be adjusted according to the distance from the Planckian or daylight locus on the CIE 1960 uv chromaticity diagram at different CCTs. Thus, the tunability of γ_α,V value of the C/A/R LED cluster at a specific CCT could be applied to different requirements for nonvisual performance.     

Optimization of resolution by FDTD analysis in aligner lithography

A mask aligner can transcribe a pattern from a photomask to an exposure substrate by Fresnel diffraction. A diffraction fringe, specific to Fresnel diffraction, appears on a light intensity distribution of the pattern (a diffraction pattern image), and the formation of the pseudo-pattern restricts the resolution performance. The diffraction fringe can be smoothened by expanding the spread of the illumination source, and thus, the pseudo diffraction can be attenuated. However, this also causes a change in light intensity at the pattern edge to be attenuated, and the error of pattern line width to process change becomes large. Since edge diffraction patterns can be calculated by finite difference time domain (FDTD) analysis, the size of light source providing optimum resolution can be predicted by calculating and comparing pattern images corresponding to the size of the light source using this analysis. Therefore, by introducing an illumination optical system that can arbitrarily set the size of a light source to a predicted value, optimum resolution can be obtained without prior trial exposure. This study shows that the resolution of an aligner can be optimized by prior prediction, by introducing a multiple smoothing optical system that has been developed as an illumination system. This system realizes uniform illumination distribution on both a pupil plane and photomask plane and has an adjustable aperture mechanism that, by combining it with FDTD analysis, can arbitrarily set the size of the light source.     

基于保真度的量子信令纠缠交换最佳交换速率

为了解决量子信令交换的最佳交换速率问题,提出了基于保真度的量子信令纠缠交换最佳交换速率算法。根据量子信令纠缠交换方案,分析了由量子混合态组成的信令保真度。针对单输入单输出系统（SISO）和多输入多输出系统（MIMO）,讨论了影响量子信令交换速率的各种因素,计算得出最佳交换速率。仿真结果表明,在保真度为97%时,最佳交换速率为100qubit/s,该指标完全能够满足量子通信对信令交换的要求,对于构建未来量子通信系统有着重要的技术支撑作用。     

在双模腔QED系统中用原子-腔共振相互作用实现三量子比特Toffoli门

提出了一种在腔QED系统中用一个五能级原子通过原子-腔共振相互作用实现三量子比特Toffoli 门的方案。在提出的方案当中,两个量子化的腔模充当控制比特,而原子的两个低能态构成目标比特。数值结果表明,当同时考虑原子高能态的自发辐射和腔模的衰减对量子门的保真度的影响时,腔场的衰减是主要的噪声来源。讨论了原子-光场耦合常数的偏差对三量子比特Toffoli 门保真度的影响以及方案在实验上的可行性。     

双光子过程中原子和光场量子态保真度的演化

考虑了动态Stark移位,通过计算双光子过程中压缩相干态的保真度,讨论了双光子J-C模型中能级的动态Stark移位和光场的压缩因子对量子态保真度的影响.研究表明:保真度的演化呈现明显的量子崩塌-复苏振荡.当考虑动态Stark移位时,通过比较可以明显看出,在量子信息的处理和传递过程中,原子、场和系统的保真度明显好于不考虑动态Stark移位的情形.初始场强调制了原子、场和系统保真度演化的量子崩塌复苏周期,使场保真度演化中的振荡脉冲变窄.同时,压缩因子影响着体系中原子和场之间的能量交换.     

The quality of evidence in tablet‐assisted interventions for students with disabilities

The purpose of this review is to weigh the evidence of the effectiveness of tablet‐assisted instructions (TAIs) at improving academic outcomes of students with disabilities. An extensive search process with inclusion and exclusion criteria yielded a total of 17 studies to be included in the present study: three group design studies and 14 single‐subject design studies. The quality indicators proposed by Gersten et al. ( 2005 ) and Horner et al. ( 2005 ) were applied to evaluate the methodological rigour of TAI studies and their feasibility to be considered evidence‐based. Results revealed that (a) most group design studies provided little information about the intervention agent and equivalence of groups across conditions, (b) the social validity of using tablets for students with disabilities was strongly established across all single‐subject design studies and (c) procedural fidelity in assessment and intervention implementation was inadequately addressed in group design studies. Although this review suggests that TAI used in single‐subject design studies can be a potentially evidence‐based practice for students with disabilities, there still remains to be established whether the group design studies can be considered evidence‐based, because of the lack of methodological rigour in group design studies. Finally, implications for future directions and practical ideas are discussed.     

LED显示屏的色度均匀性和色保真度

全彩色LED显示屏的均匀性包括亮度均匀性和色度均匀性两个方面。均匀性不好，显示屏就会出现”花斑”或”马赛克”，严重影响图像的观看效果。其中色均匀性包括均匀性和色保真度两个方面。色均匀性是指同屏各个象素、模块和模组之间显示同一种颜色时的色差：色保真度则是指显示屏上的图像与源图像或源景物之间的色重现的吻合程度。这两个问题都涉及到LED色差的原因和计量，为了提高色均匀性和色保真度，必须减少色差，为此研究了进行色修正和补偿的方法。     

Virtual math objects with pedagogical,mathematical, and cognitive fidelity

The examination of mathematical and cognitive fidelity for math related websites has been studied by Web designers; yet teachers, and especially pre-service teachers, as users of technology in the classroom, also need to be familiar with pedagogical, mathematical, and cognitive fidelity. What is pedagogical, mathematical, and cognitive fidelity; and, what makes a math website high in pedagogical, mathematical, and cognitive fidelity are discussed in this article. Evidence is shown that technology high in pedagogical, mathematical, and cognitive fidelity, when used in the classroom, improves student academic achievement.     

DEM保真精度定量化描述模型

等高线回放法是数字高程模型(DEM)精度评估的重要方法之一,可以用于检测地形的保真程度,但是现有定量评估指标属于相对保真精度的范畴,因此基于水系和地形的固有套合特性,提出了水系和地形套合隶属度函数,从两者的套合程度实现DEM保真精度的定量化描述.首先,根据线状要素位移准则、尺度准则、平均坡度准则、最大套合偏移量准则和目视效果准则,运用模糊数学方法建立水系和地形套合隶属度函数;然后,使用4个不同地貌类型实验区域的1∶5万地形图作为基础源数据,实验分析了DEM保真精度的评估.实验结果表明水系和地形套合隶属度函数不仅可以用于DEM保真精度的定量评估,而且可以用于DEM最佳分辨率的确定以及DEM尺度转换适宜范围的确定.     

基于CC1100的心电遥测系统设计与实现

介绍了一种采用CC1100芯片设计的心电信号无线收发系统,详细地给出了系统的软硬件设计.该系统具有体积小、功耗低、成本低和信号高保真等特点,同时也实现了心电监护仪中信号采集与分析处理的分离,具有很好的应用价值.