CIE1931色度图非线性均匀化

本文采用了一种全新的非线性均匀化方法,引入收缩参数,使用Matlab优化程序对C(?)E1931色谱图进行了优化变换,得到的新色谱图与C(?)E1960UCS色谱图相比,均匀性有了一定的改善。     

CIE2000色差公式在涂料色差评定中的应用

对比了CIE2000公式和CIELab公式,并通过实验比较了这两种色差公式对不同色域范围的颜色评定差别,籍此来优化目前涂料行业广泛使用的CIELab色差公式评定标准。     

基于CIE LAB色差公式的翡翠绿色明度差对色差的贡献

通过翡翠绿色的色差计算,分析明度差DL、彩度差DC、色调差DH对综合色差DE的贡献.采用CIE L*a*b*均匀色空间中CIE LAB色差公式的计算结果显示,肉眼下66粒质地细腻、绿色均匀的优质翡翠戒面的明度值L*∈(38.50,61.80),属中等偏低的明亮程度;彩度范围C*∈(11.49,44.99),也属中等偏低;色调范围h0∈(134.32,152.96),属略带黄色调的鲜艳绿色.翡翠绿色的平均色差DELAB-AVE=6.10达肉眼可识别级别,平均饱和度差-0.22与平均色调角差0.06均很低,对总色差贡献不大,而明度差DL则表现出了与总色差很高的一致性.得出结论,对中低明度的翡翠绿色色差的最直接贡献者为其明度差,依此建议采用首先以彩度和色调的二元体系作为翡翠绿色定量分级体系,进而依据三维均匀色空间模型CIE L*a*b*,构建以色差为基本单位,明度为Z轴、彩度为X轴和色调为Y轴的三元质量分级体系.     

基于CIE 1976 L* a* b*色空间的翡翠绿色明度的质量评价

通过翡翠绿色明度与彩度、明度与色差等关系的研究,确定明度对颜色质量评价的作用.三维均匀色空CIE 1976 L* a* b*中,当翡翠绿色的明度较低即L*<19.52时,明度与彩度呈正相关;当19.5260时,明度则与彩度呈负相关.通过CIE DELAB、DECMC、CIE DE2000三个色差公式的计算,证明DL*是决定DE的直接因素, DC*次之,而DH*对色差几乎无贡献.得出结论,翡翠绿色的质量评价应以明度为首要因素,这是最直观且最符合色知觉效果的,而后依次为彩度与色调角两个标准.     

CIE 1976(L*a*b*)色空间在PVC-U型材颜色测量中的应用

通过对GB 11186-1989《涂膜颜色的测量方法》标准中关于CIE 1964补充标准色度系统、CIE 1976(L*a*b*)色空间的色坐标及色差公式和光与颜色的相关理论的分析,解析了GB/T 8814-2004《门、窗用未增塑聚氯乙烯(PVC-U)型材》中有关型材颜色测量要求,并给出了灰卡级数与总色差的换算关系。     

CIE1976 L*a*b*均匀色空间下照度对锰铝榴石颜色的评价

通过照度实验,基于CIE1976L*a*b*均匀色空间研究照度对锰铝榴石颜色评价的影响.照度增加,锰铝榴石黄色的明度L*显著增加,且自身明度较低的锰铝榴石黄色明度更易受照度变化的影响.△a*平均为17.30,△b*平均为36.83,明显大于△a*的均值,表明照度对锰铝榴石黄色调的影响更大;当照度较低时,彩度C*与照度呈正相关,当照度超过227.73 lx后,C*将不再增大或与照度呈负相关;色调角h0随照度增加而增大,平均色调角增量△h0=11.59,增幅较明度和彩度小.同时验证Stevens效应、Hunt效应、Helmholtz-Kohlrausch效应、Bezold-Brücke色相偏移理论在锰铝榴石颜色观察上的体现.此外,当明度差值DL* ＞15时,DL*与色差DE2000呈正相关且相关性最大,说明明度对色差具有最大贡献.得出结论,照度影响锰铝榴石的明度、彩度、色相,间接影响色差,其中对明度影响最直观,故在质量评价时应严格控制照度标准.     

The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.     

The impact of the discovery of the polymerization of the α-olefins on the development of the stereospecific polymerization of vinyl monomers

After a short survey of the first indications on the existence of stereoregularity in the main chains of the vinyl polymers, the first syntheses of stereoregular poly(vinylethers) and polystyrene are briefly summarized. The difficulties encountered in the early investigations of the propylene polymerization by the CoO/MoO₃/Al₂O₃ and CrO₃/SiO₂/Al₂O₃ catalysts are considered and the isolation and identification of a crystalline component in the mixture of diastereomeric macromolecules thus obtained, are discussed. The results obtained by different research groups, independently investigating the stereospecific polymerization of vinyl monomers, are compared and finally an attempt is made to explore the origin of the very rapid progress made in this field by Natta and coworkers in connection with their discovery of the stereospecific polymerization of α-olefins with the ‘Ziegler-Natta catalysts’.     

Wind energy — the fuel of the future

Over the last six years wind power has become the world's fastest growing energy technology, and growth rates of 20% a year are predicted for the next     

Dependence of the Time‐Space Structure of the Chemical‐Reaction Zone on the Initial Density of the Explosive

The results of a study of the chemicalreaction zone structure for a number of high explosives (HEs) are discussed. It is found that an increase in the initial density of the HEs leads to a structural change in the chemicalreaction zone involving elimination of the Von Neumann spike at the critical density point. Conversely, as the initial density of the explosive decreases, the ratios of the gasdynamic parameters (in particular, mass velocities) at the Von Neumann point to the same parameters at the Jouguet point increase. It is shown that to explain the indicated regularities, one does not need to invoke the assumption of an increasing contribution of the exothermic decomposition of the HE the shock. The results can be explained within the framework of classical Zeldovich–Von Neumann–Döring theory with an ordinary shock at the detonationwave front and, hence, with a nearly zero contribution to the total energy release in the chemical reaction zone.     

Influence of the glass–calcium carbonate mixture's characteristics on the foaming process and the properties of the foam glass

We prepared foam glasses from cathode-ray-tube panel glass and CaCO₃ as a foaming agent. We investigated the influences of powder preparation, CaCO₃ concentration and foaming temperature and time on the density, porosity and homogeneity of the foam glasses. The results show that the decomposition kinetics of CaCO₃ has a strong influence on the foaming process. The decomposition temperature can be modified by varying the milling time of the glass–CaCO₃ mixture and thus for a specific CaCO₃ concentration an optimum milling time exists, at which a minimum in density and a homogeneous closed porosity are obtained. Under the optimum preparation conditions the samples exhibit a density of 260 kg/m³. The thermal conductivity of the foam glass was measured to be 50–53 mW/(m K). The observed dependence of the foaming process on the decomposition kinetics of the foaming agent can be applied as a universal rule for foaming processes based on thermal decomposition.     

Response to the “Letter to the Editor”

Please click here to find the Letter to the Editor to which this Response refers: http://dx.doi.org/10.1080/02786826.2012.684412

Copyright 2012 American Association for Aerosol Research     

Effect of chromium on the kinetics of the contact melting and the graphite-to-diamond transformation in the Co–Fe–C system

We have studied the effect of chromium concentration in alloys of the Co–Fe system on their interaction with graphite at p, T parameters of thermodynamic stability of diamond. It has been found that addition of chromium to the alloys stabilizes the Me₃C-type carbide, as a result, the structure of a layer of a contact melting at the alloy–graphite interface is identical to a horizontal section of the metastable phase diagram of the Fe–C system. It is shown that addition of chromium to the Co–Fe–C system lowers the eutectic melting temperature by 80–100 K. In this case, the coefficient of carbon diffusion in the melt increases by ∼20–30%. An increased surface activity of a Cr-containing melt with respect to graphite is noted, which is the reason of intensive intrusion of the melt deep into a graphite layer along the grain boundaries. As a result, the number of nucleating diamond crystals and the degree of the graphite→diamond transformation increases.     

Note of the estimation of the Θ temperature and Ψ parameter from the critical temperature data

Summary Critical values of the polymer volume fraction _2,c and the interaction parameter _c have been computed for the case that the equation for the chemical potential of solvent contains terms _{c 2} ³ and _{c 2} ⁴ in addition to ₂ ² . For 0 _c 1/3, the limits for infinite chain length are _2,c = 0 and _c = 0.5. Quite different results are obtained for _c > 1/3, _2,c being finite and _c lower than 1/2. Conclusions for the estimation of the temperature and the entropy-of-dilution parameter are discussed.     

Role of the Initial Formation of the Iron Nano-Particles in the Multi-Walled Carbon Nanotubes Growth Process

Careful preparation of the iron nano-particle catalyst for carbon nanotubes (CNTs) fabrication has crucial importance for initial growth of multi-wall carbon-nanotubes (MWCNTs). Thin iron layer was thermally deposited in a high vacuum onto the surface of the SiO2/Si wafer at about 300 K. The sample was heated up to 700℃ in a hydrogen atmosphere, and then the sample was heated once again at750℃ in ethylene atmosphere. After hydrogen treatment continuous Fe layer was changed into many well separated Fe nano-peaks. AFM, SEM and HR-TEM studies of deposited MWCNTs allow us to propose a growth mechanism for long, straight MWCNTs.     

Does the Rainbow Trout Ovarian Fluid Promote the Spermatozoon on Its Way to the Egg?

The fertilization of freshwater fish occurs in an environment that may negatively affect the gametes; therefore, the specific mechanisms triggering the encounters of gametes would be highly expedient. The egg and ovarian fluid are likely the major sources of these triggers, which we confirmed here for rainbow trout (Oncorhynchus mykiss). The ovarian fluid affected significantly spermatozoa performance: it supported high velocity for a longer period and changed the motility pattern from tumbling in water to straightforward moving in the ovarian fluid. Rainbow trout ovarian fluid induced a trapping chemotaxis-like effect on activated male gametes, and this effect depended on the properties of the activating medium. The interaction of the spermatozoa with the attracting agents was accompanied by the “turn-and-run” behavior involving asymmetric flagellar beating and Ca²⁺ concentration bursts in the bent flagellum segment, which are characteristic of the chemotactic response. Ovarian fluid created the optimal environment for rainbow trout spermatozoa performance, and the individual peculiarities of the egg (ovarian fluid)–sperm interaction reflect the specific features of the spawning process in this species.     

How good is the evidence for the lipid hypothesis?

The evidence for the lipid hypothesis is weak. After 20 years of follow‐up, the Nurses Health Study, a prospective cohort study, was no longer able to demonstrate an association between intakes of saturated fat and risk of developing coronary heart disease. Randomised controlled trials with statins have shown that lowering LDL‐cholesterol levels by 23% can reduce the risk of developing cardiovascular disease but reducing saturated fat can only reduce cholesterol levels by 10%. This issue can only be resolved by carrying out randomised controlled dietary trials with CVD endpoints. Although there are scientific difficulties standing in the way of such trials, it is the opinion of this author that these can be overcome. Whether there is the political will to fund them is another matter although some of the money currently spent on prospective cohort studies would be far better spent on randomised controlled trials.