Towards traceable particle number concentration standard: Single charged aerosol reference (SCAR)

A concept of realizing a standard for aerosol particle number concentration was tested, based on generating singly charged aerosol particles in the size range from 10 up to 500 nm. To this end, a device named single-charged aerosol reference (SCAR) was designed, built, and tested. The device is based on electrical charging of nanoparticles and subsequent growth of the particles. With an accurate measurement of volume flow and electrical current from the singly charged particles, the number concentration can be accurately, and in the end, traceably determined. Laboratory tests have shown that the device can be used to generate a narrow (GSD<1.3) particle size distribution of singly charged particles. The device can be used for traceable calibration of instruments measuring the number concentration of the particles.     

深色活性染料的近期进展

讨论了深色活性染料的发展现状,指出今后进一步发展的焦点在于提高活性深黑的固色率和改进活性深红的湿处理牢度,对目前存在的问题提出了改进措施。     

Alternative mathematical approaches to shade sorting

Shade sorting is the process of assigning samples of the same nominal color into groups having no significant color variation. Use of modern spectrophotometers and color measurement technology make it possible to obtain precise color differences between samples. When these color differences are viewed as distances between points, the shade sorting problem is seen to be equivalent to the clustering problem in the mathematical literature. Several mathematical techniques for clustering—complete linkage clustering, vertex labeling, and set covering—are explained and compared for their efficiency when applied to shade sorting. A particular implementation of complete linkage clustering called Clemson Color Clustering (CCC) is found to perform well as compared to the other reviewed methods. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 368–375, 2000     

Using discrete optimization for designing dental shade guides

A key criterion in the design of dental shade guides used for matching tooth color is that the shade tabs cover the natural tooth color space as completely as possible with a manageable number of tabs. Earlier studies have designed hypothetical shade guides from a given population of tooth colors described in the CIELAB system using the goal of minimizing the mean coverage error. In this study, we investigate this topic using the goal of maximizing coverage, meaning that as many measured colors as possible were within a given color difference from the nearest shade tab of the guide. We use techniques of linear discrete optimization to determine the positions of the shade tabs and consider both color difference formulas, CIELAB and CIEDE2000, in an exemplary tooth color population. We obtain coverage error and coverage figures for hypothetical shade guides of various numbers of tabs designed with the goal of either minimizing coverage error or maximizing coverage. Results show that discrete optimization and the goal of maximizing coverage could be used to improve shade guide development. The described technique could be used not only for dental shade guides development, but also for any purpose requiring coverage of as many colors as possible while keeping the number of reference colors manageable. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010     

质子交换膜燃料电池的脉动进氢实验

基于实验室自制的质子交换膜燃料电池（proton exchange membrane fuel cell, PEMFC）及相关设备搭建测试平台,设计并进行了与可能影响燃料电池输出性能的因素相关的三组实验,即从不同位置脉动进氢,改变其脉动压强,调整负载电压继而研究燃料电池在恒压模式下的输出电流随时间变化的关系。测试结果表明：采用脉动进氢比频繁排水更能提高输出电流;从阳极出口脉动进氢及增大其脉动压强均有助于提高输出电流;当负载电压增大到一定程度后,燃料电池仅靠脉动进氢即可完全取消周期性排水;在某一负载电压下,脉动进氢的参数组合存在使系统获得最优的输出功率及其稳定性的对应值。     

粘接型氯丁橡胶胶液色泽的改进

研究了终止剂、抗氧剂的种类及用量对粘接型氯丁橡胶甲苯溶液色泽以及生胶贮存稳定性的影响。结果表明:当采用盐酸羟胺做终止剂,2.6-二叔丁基对甲基苯酚做抗氧剂,所得氯丁橡胶具有良好的贮存稳定性,其甲苯溶液色泽较浅。     

A review and assessment of numerical shade sorting methods

The properties of current shade sorting geometries are evaluated on a mathematically generated, spherical population of normally distributed data points. The results compare well with those obtained from preuiously cited populations of textile production goods. Thefixed-grid geometries (cubic, rhombic dodecahedra1 and truncated octahedral) are not as efficient in terms of the numbers and uniformity of shade sorting groups as the grid-free spherical clusters employed by Clemson Color Clustering (CCC).     

A shade guide model based on the color distribution of natural teeth

The objectives were to determine the color distribution of natural teeth sorted by the parameters of Value, Chroma, and hue angle measured with a colorimeter, and to suggest a shade guide model. The color of maxillary and mandibular 12 anterior teeth was measured with a tristimulus colorimeter for 47 subjects (n = 564). The color of teeth was grouped initially by Value (CIE L*) by the interval of 3.3 units. After then, within each main group, the color of teeth was subgrouped by Chroma by the interval of 3.3 units. Chroma was calculated as C*_ab = (a*2 + b*2)^1/2. Since the hue angles were in the first or fourth quadrant, subgroups were further sorted by the first or fourth quadrant hue angles. Hue angle was calculated as h° = arctan (b*/a*). Mean color difference (ΔE*_ab) between the color of an individual tooth and the mean color of each main group was 2.5–3.3, which was lower than acceptable limit (ΔE*_ab < 3.3), and that in each subgroup was 0.9–3.1. The number of subgroups was 22, which was comparable to those of conventional shade guides. A shade guide model based on the color distribution of natural teeth sorted by Value in six main groups, three or four subgroups within each main group sorted by Chroma, and further sorted by hue angle (first or fourth quadrant values) was suggested. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 278–283, 2007     

Effective carbon number molecular weight carbon number Pressure Temperature

A method based on the effective carbon number (ECN) has been developed for the prediction of the vapor pressures of carboxylic acids over a range of temperatures. Good representation of the vapor pressures is obtained in the range 1 kPa to HOkPa with an overall average absolute deviation of 2.26%for 31 carboxylic acids which included saturated as well as unsaturated acids. The method requires a knowledge only of the normal boiling point or the boiling point at 1.3 kPa (lOmmHg) of the substance     

单身礼

情人节是情侣们大秀恩爱甜蜜的节日,而11月11日则是专属于单身人士的节日. 在这个日子里,为自己选-枚精美别致的单身戒,自己宠爱自己;或者宅在家里玩＂单身贵族棋＂和＂桌面保龄球＂,一个人,其实也可以很快乐. 如果想结束单身的话,带着＂Momiji娃娃＂去参加单身派对吧,或者赶紧把＂月小老＂请回家.幸福,就在下一站.     

Using principal component analysis technique in the instrumental shade sorting of textile fabrics

In the present study, the CCC shade sorting method was employed with CMC(2:1) color difference formula on the colorimetric data (CIEL*a* b*) of 37 fabric color sets. The k‐means non‐hierarchical clustering technique was also combined with the CCC shade sorting method to increase its efficiency. The results of this combined method showed a slightly better performance, as compared with the CCC method. Also, a new proposed shade sorting method by the application of principal components analysis (PCA) technique was used to identify and remove the outliers in each of the color sets. The results of separating the outliers showed that although the diameter of group criterion was improved significantly, the number of groups, the number of singleton groups, and the number of groups with low samples were increased considerably. Finally, in a second new proposed shade sorting method, PCA was used as a data reduction tool on the colorimetric data of the 37 color sets. Then, the two first principal components in combination with a k‐means clustering technique were used for the clustering of the samples in each color set. The results of this second new proposed method were found to be similar to the CCC method considering number of group and fabric consumption criteria. The second new proposed method revealed a moderately worse result, with regard to the diameter of group criterion, than the CCC method.     

单身礼

情人节是情侣们大秀恩爱甜蜜的节日,而11月11日则是专属于单身人士的节日. 在这个日子里,为自己选-枚精美别致的单身戒,自己宠爱自己;或者宅在家里玩"单身贵族棋"和"桌面保龄球",一个人,其实也可以很快乐. 如果想结束单身的话,带着"Momiji娃娃"去参加单身派对吧,或者赶紧把"月小老"请回家.幸福,就在下一站.     

CR-244氯丁橡胶及甲苯胶液色泽的改善

笔者从聚合配方和终止剂体系两个方面入手，介绍了改善CR-244氯丁橡胶及甲苯胶液色泽并能保证其抗老化性能的方法。     

Instrumental shade sorting of coloured fabrics using genetic algorithm and particle swarm optimisation

In the present research by combination of Clemson Colour Clustering (CCC) instrumental shade sorting method and two metaheuristic algorithms, a genetic algorithm (GA) and a particle swarm optimisation (PSO), two new shade sorting methods, called CCCGA and CCCPSO were proposed. Then these proposed methods were applied on 16 well-prepered colour sets made of coloured fabrics and their results were compared using some important performance evaluation factors. The results of the methods were also compared with conventional CCC shade sorting method and a method based on CCC combined with k-means technique (CCCk). The results obtained from various shade sorting methods showed that the CCCGA and CCCPSO methods successfully sorted the coloured fabrics with high efficiency, and their results slightly outperformed the results of the CCC method.     

Regression analysis to determine the optimum colour tolerance level for instrumental shade sorting

An investigation of the correlation between visual colour assessment and instrumental colour acceptance determination using regression analysis has been carried out. Three colour-difference equations, CIELAB, CMC(2:1) and CIE94(2:1:1), were studied in order to determine which is the best for generating a uniform colour space/microspace for allocating the colour population in shade sorting. Determination of optimum colour tolerance for further shade sorting was also undertaken. Some 1320 pairs of dyed samples distributing around 20 shade standards were measured instrumentally and also evaluated visually by a panel of 32 observers. Percentage rejection was plotted against colour difference and different mathematical regression relationships were then imposed. As a result, both CMC and CIE94 showed better correlation between the two colour assessment methods than the CIELAB colour-difference equation. Consequently, optimum colour tolerance limits were determined for subsequent development of shade sorting, with the findings being equally applicable to colour acceptance (shade passing).     

Achieving expected depth of shade in reactive dye application using artificial neural network technique

Achieving the expected depth of shade in the production of dyed goods is a very important aspect. It requires the termination of the process at the right time in other words, correct duration of dyeing should be used. Prediction of this duration for the application of reactive HE dyes on cotton fabric using artificial neural network (ANN) is reported. The results obtained from the network gives an average training error of around 1% in the prediction of the time duration for achieving the correct depth of shade. The trained network gives the same average error % when tested with other reactive HE dyes even when the input parameters selected are beyond the range of inputs, which were used for training the network.     

Effect of ingredients of accent base on shade development in point of sale tinting

The proper dispersion and stabilization of titanium dioxide/extender in a coating is critical for color development. Color development is much more challenging when it comes to point of sale tinting. This color needs to be reproducible and accurate after machine tinting. What decides the color development in a zero rutile base containing extenders? This article studies the raw material interactions and its effect on color development.