CIE94 CIEDE2000色差公式均匀性分析

利用孟塞尔(Munsell)颜色系统,在视觉上为等色差系统以及色调、彩度和明度可以单独改变的特性,选择明度V=5的色块,分别从色调、彩度两方面对CIE94、CIEDE2000色差公式的均匀性进行了研究.数据计算结果表明,它们计算出的色差值是比较一致的;但它们的均匀性是不同的.需要针对不同的彩度、色调选择使用不同的色差公式.     

CIEDE 2000色差公式的研究

CIEDE 2000色差公式是迄今为止最为先进的色差计算公式.但是,此公式在色彩工作的使用过程中发现其在某些数据点的计算上出现间断,即数学中常提到的不连续性.本文使用数学不连续性的方法旨在从理论上证明公式中存在的小的数学不连续性.计算结果表明,此公式存在三方面的不连续性,即平均色相角的计算、色相差的计算和色相角在经过360°时均存在不连续性.最后,简单的介绍了公式中不连续性的应用.     

CIE94色差公式在包装行业的应用探讨

分析了印刷行业和包装行业目前正在使用的CIE 1976 LAB色差公式,全面介绍了CIE94色差公式,建议印刷行业和包装行业使用CIE94色差公式作为色差评价的主要工具.     

基于CIEDE2000色差公式权重函数修正的研究

为了对CIEDE2000色差公式计算中等色差时的权重函数SL,SC进行修正,使计算结果与人眼的视觉感觉相一致,选用了孟塞尔(Munsell)颜色系统中的中等明度和中等彩度色块,在5R、5Y、5G、5B 4个主色调的颜色区域分别改变明度和彩度进行计算,改变彩度时共有34对样品,改变明度时共有25对样品,得到新的修正系数.用修正后的权重函数计算Munsell颜色样品和实验制作的改变明度和彩度的24对中等色差样品,验证了修正后的色差公式在计算中等色差时,色差公式的均匀性以及与人眼的视觉感觉的线性相关性都有了较大的提高,可用于对彩色印刷品的颜色评价.     

CIE DE2000在彩色扫描仪特征化色差评价中的应用

采用支持向量回归机(SVR)建立了RGB色空间到CIE Lab色空间的转换模型,分别采用CIE DE2000与CIE 1976L*a*b*色差公式对模型精度进行色差计算。采用CIE DE2000色差公式得到的测试组色差平均值、最大和最小值分别为2.659 7,5.219 4和0.206 5,采用CIE 1976L*a*b*色差公式得到的测试组色差平均值、最大和最小值分别为2.865 6,5.879 1和0.376 9。实验结果表明,CIE DE2000与CIE 1976L*a*b*色差公式计算的色差值基本一致,均符合彩色扫描仪特征化精度要求,可将CIE DE2000色差公式用于扫描仪特征化管理中。     

杠杆千分尺校准和测量能力(CMC)的评定

本文按中国合格评定国家认可委员会(CNAS)的要求,对杠杆千分尺示值误差的测量不确定度进行了详细评估,给出了杠杆千分尺的校准和测量能力(CMC)。     

a-Si:H/a-Si_(1-x)C_x:H 多层膜的电学和光学性质

采用等离子体辉光放电单室系统制备的 a-Si:H/a-Si_(1-x)C_x:H 多层膜结构具有低的暗电导和高的光电导特性,且不同于单层膜,有明显的 S-W 效应。随着子层厚度 L 减小,多层膜曝光态(B)的暗电导率σdB 较退火态(A)的σdA 减小快,即光诱导衰退程度增大,而光电导无明显变化。本文还测定了此多层膜结构的光能隙 E_g,得到随子层厚度减小“蓝移”的结果。用一维单量子阱模型作了讨论,实验值与理论计算符合较好。     

a-Si_(1-x)Nx:H 光电导的改善及其原由

氮的掺入能够改善 a-Si∶H 的光电导性。用 ESR 方法难以分析其原因。吸收系数的弱吸收段却能显示出氮造成 a-Si∶H 缺陷态密度的变小。当掺氮量 x(?)0.01时,a-Si_(1-x)N_x 之ημT 值呈最大,在 E_(?)下1.2eV 处缺陷态密度最低,约3.3×10~(15)/cm~3。过量地掺氮则导致缺陷态密度增加,光电导降低。     

基于GM(1,1)的建筑废弃物资源化利用研究

针对建筑废弃物难以量化问题,通过面积指标法,估算历史年份的建筑废弃物产量,建立了基于灰色系统理论GM(1,1)的产量预测模型.以国内某城市为例,预测"十四五"期间建筑废弃物产量,并提出建筑废弃物处理与资源化利用的相关措施.     

An exploratory study of the impact of information communication technology (ICT) or computer mediated communication (CMC) on the level of violence and access to service among intimate partner violence (IPV) survivors in Canada

This paper presents exploratory research on the use of information communication technologies (ICTs) or computer mediated technologies (CMCs) (i.e., cell phones and the internet) among immigrant women who are intimate partner violence survivors (IPV) in Canada. The discussion begins with a presentation of initial data examining the impact of such technology on the level and extent of violence experienced by IPV survivors, and on their ability to access appropriate services. Furthermore, an assessment of whether this form of technology aided in the development of a prevention or safety plan, is explored. The data is based on non-random sample surveys of immigrant women IPV survivors with Canada. While the limited scholarship on ICT or CMC usage indicates that there is a digital divide and that various socio-demographic factors do play a role in utilizing the technology, our data does not display a black and white or any streamlined pattern with regards to the digital divide and sociodemographics factors. An examination of the participants' various sociodemographics indicates that the digital divide within this population is not influenced by access or knowledge to the technology but by other factors often not discussed in the intersectionality models. An intersectional model of race and immigration status along with the existing literature on intimate partner violence among immigrant women especially issues of isolation and social networking inform this paper.     

Dissociation pathways of oxygen on copper (1 1 0) surface: a first principles study

We have carried out first principles calculations to examine the adsorption and dissociation of oxygen on the Cu (1 1 0) surface. At low coverage, our results indicate two absorption species: a peroxo- and a superoxo-like species which have direct implications to the dissociation process. In agreement with experimental studies, the most favourable absorption site for O₂ is found to be the 4-fold hollow site. The dissociation barrier at this site is only 150 meV, which is consistent with experimental findings. Static calculations also reveal other possible dissociation pathways with significantly different energy barriers. First principles MD simulations are used to probe the dynamics of the dissociation process. We find only selected pathways are likely to be utilised because of interaction with the surface.     

Evolution of interface diffusion and structure of Ni films sputter-deposited on Si(0 0 1)

Ni films were deposited on Si(0 0 1) substrates at 190°C by dc plasma-sputtering in Ar gas in order to investigate the Ni diffusion phenomena into the substrate and its effect on the structure of Ni films. The deposition time was 10, 15 or 30 min. The Ni/Si samples were studied by cross-sectional transmission electron microscopy and Rutherford backscattering. Ni adatoms are confirmed to diffuse into the Si substrate forming a diffusion layer. The diffusion layer consists of two regions. The first one is of homogeneous thickness and locates adjacent to the interface of film and substrate. The second one consists of several isosceles triangles with vertex angle of about 70° standing on the front of first region. Both the thickness of the first region and the number of triangles in the second region increase with increasing deposition time. The compositional ratio of Ni to Si in the diffusion layer is 1.3±0.1. The Ni films have a lot of voids at the interface and a rough surface. The density of the film is estimated to be 25% lower than that of bulk Ni. The thickness of the Ni films does not increase linearly with deposition time.     

Energetics of Ge addimers on the Si(1 0 0) and Ge(1 0 0) surfaces: a comparative study

The adsorption energetics of Ge dimers on the (1 0 0) surfaces of Ge and Si has been investigated using the first-principles molecular dynamics method. Four high-symmetry configurations have been considered and fully relaxed. The most stable configuration for Ge dimers on Si(1 0 0) is found to be in the trough between two surface dimer rows, oriented parallel to the substrate Si dimers. These results are consistent with recent experimental studies of the system using the scanning tunneling microscopy (STM), and help to clarify some existing controversies on the interpretation of the STM images. In contrast, for Ge dimers on Ge(1 0 0), the most stable configuration is on top of the substrate dimer row.     

Mg_xZn_(1-x)O:Al靶材制备工艺和Mg掺杂对微观结构的影响研究

以纳米级的ZnO、MgO和Al2O3粉体为原料,经过湿式球磨得到了混合粉体,采用常压固相烧结的方法制备了高致密度MgXZn1-XO:Al陶瓷靶材,研究了预烧粉体、Mg掺杂量和烧结温度对靶材微观结构和性能的影响.研究表明,预烧粉体可以减少第二相的生成;随着Mg掺杂量的增加,MgO立方相逐渐增多,在x=0.3时产生了相分离;在1100～1300℃内,随着烧结温度的升高,靶材的晶粒大小和密度逐渐增大,增大趋势在1300℃后变缓,1300℃烧结4h可以制得结构均匀、高致密度的MgxZn1-xO:Al靶材.     

Nd:Gd_xY_(1-x)Ca_4O(BO_3)_3晶体的生长及其光谱性能研究

利用熔体提拉法生长了大尺寸,高质量的新型激光自信频晶体Ｎｄ：ＧｄｘＹ１－ｘＣａ４Ｏ（ＢＯ３）３简称Ｎｄ：ＧｄＹＣＯＢ）．对Ｎｄ：ＧｄＹＣＯＢ晶体的ＸＲＤ衍射图进行指标化,得到它的晶胞参数为α＝８．０８０Ａ; ｂ＝１６．０１６Ａ; ｃ＝３．５３８Ａ; β＝１０１．１８°;μ＝４９１．１Ａ３．对取自不同部位的晶体粉末进行ＩＣＰ原子发射光谱分析表明晶体整体组份均匀一致,根据熔体和晶体粉末的ＩＣＰ数据计算,Ｎｄ：ＧｄＹＣＯＢ晶体中Ｎｄ３＋的分凝系数为０．６３．首次报道了 Ｎｄ：ＧｄＹＣＯＢ晶体２００～３０００ｎｍ室温透过光谱和室温荧光光谱及荧光寿命．室温透过光谱表明Ｎｄ：ＧｄＹＣＯＢ晶体的紫外吸收边在～２２０ｎｍ,具有很宽的透光波段（～２２０～２７００ｎｍ）; Ｎｄ：ＧｄＹＣＯＢ晶体在８００ｎｍ附近存在很强的吸收,适合于ＬＤ泵浦．荧光光谱表明Ｎｄ：ＧｄＹＣＯＢ晶体是一种很有潜力的ＲＧＢ（ｒｅｄ;ｇｒｅｅｎ, ｂｌｕｅ）激光自信频晶体．掺杂 ４％、 ５％ Ｎｄ：ＧｄＹＣＯＢ晶体的荧光寿命分别为 １０５μｓ和１００μｓ．     

Anharmonic effects on Be(0 0 0 1): A molecular dynamics study

Using molecular dynamics simulations and a modified analytic embedded atom method (MAEAM), the anharmonic effects of Be(0 0 0 1) surface have been studied in the temperature range from 0 K to 1400 K. The temperature dependence of the interlayer separation, mean square vibrational displacement, phonon frequencies and phonon line width, and layer structure factor are calculated. The obtained results for temperature dependence of interlayer separation and mean square displacement show that the anharmonic effects are small in the temperature range from 0 K to 1100 K. The calculated layer order parameters indicate that Be(0 0 0 1) surface loses its long-range translational order, but do not premelt up to 50 K below the bulk melting point. The surface disordering may result from strongly contracted c/a ratio of Be.