Estimation equations for practical use on lightness-reflectance (L/Y) ratios in the whole chromaticity gamut

A multiple regression analysis is reported to predict L/Y ratios as a function of chromaticity coordinates x, y. the specified variables were selected statistically from the 20 terms of Ψ^mψⁿ. the quantities Ψ, ψ are the transformed values of x, y, respectively, and 1 ≦ m + n ≦ 5. the contour lines of equal L/Y ratios are estimated in the whole chromaticity gamut including spectral colors by using each of the regression equations with 6, 9, and 20 specified variables. the regression equations with 20 specified variables can satisfactorily predict the corresponding experimental results. In case of regression equations with 6 specified variables, the predicted contour lines are significantly different in shape from those of the corresponding experiments. the same defects are found in the Ware-Cowan equation only using 4 specified variables recommended by CIE Division 1 for further tests.     

Lightness dependencies and the effect of texture on suprathreshold lightness tolerances

A psychophysical experiment was performed to determine the effects of lightness dependency on suprathreshold lightness tolerances. Using a pass/fail method of constant stimuli, lightness tolerance thresholds were measured using achromatic stimuli centered at CIELAB L* = 10, 20, 40, 60, 80, and 90 using 44 observers. In addition to measuring tolerance thresholds for uniform samples, lightness tolerances were measured using stimuli with a simulated texture of thread wound on a card. A texture intermediate between the wound thread and the uniform stimuli was also used. A computer‐controlled CRT was used to perform the experiments. Lightness tolerances were found to increase with increasing lightness of the test stimuli. For the uniform stimuli this effect was only evident at the higher lightnesses. For the textured stimuli, this trend was more evident throughout the whole lightness range. Texture had an effect of increasing the tolerance thresholds by a factor of almost 2 as compared to the uniform stimuli. The intermediate texture had tolerance thresholds that were between those of the uniform and full‐textured stimuli. Transforming the results into a plot of threshold vs. intensity produced results that were more uniform across the three conditions. This may indicate that CIELAB is not the best space in which to model these effects. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 241–249, 2000     

Characterization and optimization of color attributes chroma (C*) and lightness (L*) in offset lithography halftone print on packaging boards

The outcome of a print in production run plays a crucial role in commercial and packaging printing. In the growing packaging industry, colorfulness and saturated prints with high chroma attract the eye of the consumer. The design and layout of a packaging carton comprise of images that consist of halftones in the print process, which demand attractiveness and visibility using bright colors. In this research, an effort has been made to identify and analyze various parameters involved in offset lithography affecting color attributes of prints. This study also focused on the investigation of the best process conditions that would yield optimum color values through multiresponse factors such as chroma and lightness. A general full-factorial Design of Experiments (DOE) approach was used to evaluate the effect of prepress parameters such as screen ruling and dot shape and press parameters such ink viscosity and paper smoothness. These parameters were then optimized using a customized response surface design. From the experiment, it was observed that viscosity of the ink was a significant factor that majorly controls the color attributes. The surface smoothness of the paperboard was one of the factors influencing the improvement of color reproduction. A smoother surface makes even contact during ink transfer in the offset printing machine and hence reflects color with a higher chroma. The optimum parameters were as follows: 15 Pa s ink viscosity, 0.77 μm paper smoothness, and 200 lines per inch (lpi) screen ruling that resulted in increasing chroma (C*) in the middle and shadow tones in the halftones.     

Properties of (Y)ZrO2–Al2O3 and (Y)ZrO2–Al2O3–(Ti or Si)C Composites

The effect of Al₂O₃ and (Ti or Si)C additions on various properties of a (Y)TZP (yttria-stabilized tetragonal zirconia polycrystal)–Al₂O₃–(Ti or Si)C ternary composite ceramic were investigated for developing a zirconia-based ceramic stronger than SiC at high temperatures. Adding Al₂O₃ to (Y)TZP improved transverse rupture strength and hardness but decreased fracture toughness. This binary composite ceramic revealed a rapid loss of strength with increasing temperature. Adding TiC to the binary ceramic suppressed the decrease in strength at temperatures above 1573 K. The residual tensile stress induced by the differential thermal expansion between ZrO₂ and TiC therefore must have inhibited the t - → m -ZrO₂ martensitic transformation. It was concluded that a continuous skeleton of TiC prevented grain-boundary sliding between ZrO₂ and Al₂O₃. In contrast, for the ternary material containing β-SiC in place of TiC, the strength decreased substantially with increasing temperature because of incomplete formation of the SiC skeleton.     

Processing and Mechanical Behavior of CrN/ZrO2(2Y) Composites

CrN powder consisting of granular particles of ∼3 μm has been prepared by self-propagating high-temperature synthesis under a nitrogen pressure of 12 MPa using Cr metal. Dense pure CrN ceramics and CrN/ZrO₂(2Y) composites in the CrN-rich region have been fabricated by hot isostatic pressing for 2 h at 1300°C and 196 MPa. The former ceramics have a fracture toughness ( K _IC) of 3.3 MPa ·m^1/2 and a bending strength (σ_b) of 400 MPa. In the latter materials almost all of the ZrO₂(2Y) grains (0.36–0.41 μm) are located in the grain boundaries of CrN (∼4.6 μm). The values of K _IC (6.1 MPa · m^1/2) and σ_b (1070 MPa) are obtained in the composites containing 50 vol% ZrO₂(2Y).     

Y/composite titania-silica (CTS) supported catalyst for hydrotreating coker gas oil

Y/composite titania-silica (CTS) support was prepared by the in situ growth of CTS on HY zeolite. The effects of HY zeolite pretreatment and Y/CTS modification with P and F for adjusting the acidity of the support were studied. The results showed that the structure of Y/CTS was in the form of CTS as shell and HY zeolite particles as core. The content of HY zeolite affected the acidity, acidity distribution and pore structure of Y/CTS. The density of strong acid sites on the HY zeolite surface could be partly reduced by dealumination with citric acid. This reduced the CTS coverage on the outer surface of the HY zeolite, leading to the increased acidity of Y/CTS. The acidity distribution of the support could also be adjusted by P and F modification. Hydrotreating catalysts were prepared with Y/CTS as support. The catalysts were tested using the hydrotreating reaction of a coker gas oil (CGO). The experimental results showed that the catalyst hydrodenitrogenation (HDN) performance could be remarkably improved by adjusting the acidity of the catalyst support via HY zeolite pretreatment and P and F modification. The catalysts with proper Brönsted (B) acidity and Lewis (L) acidity behaved well in hydrodesulfurization (HDS) and HDN performances.     

Liquid Precursor Route for Hetero-epitaxy of Zr(Y)O2 Thin Films on (001) Cubic Zirconia

ZrO₂–3 mol% Y₂O₃„single-crystal” thin films with multiple variants were epitaxially formed on (100) cubic zirconia substrates. The films were prepared by spin-coating an aqueous zirconium acetate/yttrium nitrate solution onto the cubic zirconia substrates and subsequently heat-treated at temperatures between 1100° and 1400°C. Electron diffraction and dark-field TEM observations showed that the film has tetragonal symmetry and consists of 50–100 nm variants with their c-axes aligned with one of the three substrate cube axes. Unrelaxed strain energy estimates indicate that the two variants with their c ₁-axis parallel to the substrate/thin film interface are energetically favorable.     

Morphology of Tetragonal ZrO2 in a Ternary (Mg,Y)-PSZ

The precipitation of tetragonal ( t ) ZrO₂ in a ternary (Mg,Y)-PSZ has been studied. Nucleation of t -ZrO₂ occurs homogeneously, as in other PSZ's, and coarsened precipitates are multivariant and have an unusual tetrahedral morphology.     

Y_2O_3在（Y，Mg）－PSZ／MgAl_2O_4材料中的作用

采用工业法制备了（Ｙ，Ｍｇ）ＰＳＺ／ＭｇＡｌ２Ｏ４陶瓷材料，在１１００℃热处理过程中，材料展示了良好的耐高温老化性。微观分析结果表明：材料在热处理过程中产生ｃＺｒＯ２→ｃ′ＺｒＯ２＋ｔＺｒＯ２＋ＭｇＯ形式的共析分解反应；同时，材料中存在ＭｇＯ稳定和Ｙ２Ｏ３稳定的三种形式的四方析出体，其中Ｙ２Ｏ３稳定的“花呢”（“ｔｗｅｅｄ”）和“群团”（“ｃｏｌｏｎｙ”）状析出体随热处理时间的延长而长大     

钕(钇)-独居石固化体的研究

以硝酸铈、硝酸钕、硝酸钇、磷酸和氨水为主要原料采用共沉淀的方法合成掺杂钕(钇)的独居石固化体。通过X射线衍射仪,扫描电子显微镜,电子探针等分析技术研究钕-独居石固化体和钇-独居石固化体的化学组成和微观结构。结果表明,钕元素可以做为替代元素模拟核废物中的三价放射性核素掺杂到独居石固化体中,而钇元素则不可以。     

Photoluminescence of (ZnO)X-Z(SiO2)Y:(MnO)Z green phosphors prepared by direct thermal synthesis: The effect of ZnO/SiO2 ratio and Mn2+ concentration on luminescence

Green light emitting Zn₂SiO₄:Mn²⁺ phosphors have been synthetised by the solid-state reaction in ambient atmosphere at 1300 °C for 2 h, with ZnO, SiO₂ and MnO₂ as the reagents. The ZnO/SiO₂ molar ratio varied from 2 to 0.5. The doping level was in a lower concentration range (0.01≤x≤0.05). The effect of both the Mn²⁺ concentration and ZnO/SiO₂ molar ratio on luminescence intensity and decay was investigated in detail. The microstructure and phase composition of prepared phosphors were characterised by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). XRD results indicate that the pure α-Zn₂SiO₄ phase with rhombohedral structure was obtained after heat treatment. The prepared phosphors exhibit a strong green emission centred at 525 nm from the ⁴T₁→⁶A₁ forbidden transition. The highest emission intensity was observed for phosphors with ZnO/SiO₂ molar ratio equal to 1.0, and the Mn²⁺ concentration x=0.03 (ZSMn3). The emission intensity of the ZSMn3 phosphor is comparable with the commercial Zn₂SiO₄:Mn²⁺ phosphor. The decay curves can be characterised by double exponential function. After fitting a fast component τ₁∼2 ms and a slow component τ₂∼10 ms were obtained. The decay times decrease significantly with increasing Mn²⁺ concentration. The decay time and luminescence mechanism depend on the excitation light wavelength. Temperature dependent luminescence of the ZSMn3 phosphor in the temperature range of 25–200 °C was studied.     

氟啶虫胺腈对褐飞虱的田间防治效果

[目的]明确240g/L氟啶虫胺腈悬浮剂对褐飞虱的田间控制作用及最佳使用剂量。[方法]采用田间喷雾法,对氟啶虫胺腈37.5、50、75、100 ga.i./hm2四种不同剂量处理防治褐飞虱效果进行试验研究。[结果]240 g/L氟啶虫胺腈悬浮剂37.5、50ga.i./hm2两种剂量处理,药后1~3 d对褐飞虱的防效为51.42%~68.51%,药后7~14 d的防效为61.00%~79.10%,与对照药剂25%噻嗪酮可湿性粉剂112.5ga.i./hm2剂量处理相比,速效性相当,但持效性差;而75、100ga.i./hm2两种剂量处理,药后1~3 d防效为67.18%~74.11%,药后7~14 d防效为81.26%~89.22%,与对照药剂25%噻嗪酮可湿性粉剂112.5ga.i./hm2剂量处理相比,速效性更好,而持效性相当。[结论]240 g/L氟啶虫胺腈悬浮剂75~100 ga.i./hm2剂量喷雾处理,能有效控制褐飞虱的发生为害,可供生产上推广应用。     

Y2O3、MgO复合稳定微晶PSZ陶瓷热处理过程的研究

本文采用工业级ＺｒＯ２作主要原料,利用机械球磨混合工艺,在Ｙ２Ｏ３－ＭｇＯ－ＺｒＯ２－ＡＩ２Ｏ３四元体系中,利用ＭｇＯ、Ｙ２Ｏ３的复合稳定制备出微晶（Ｙ,ｇ）－ＰＳＺ／ＭｇＡＩ２Ｏ４陶瓷。探讨了热处理工艺过程对材料力学性能、相组成及显微结构的影响。     

Phase Stability of Fine-Grained (Mg,Y)-PSZ

A fine-grained zirconia, which has been costabilized with yttria and magnesia, has been prepared. Its stability during subeutectoid annealing at 1100^deg;C, and its hydrothermal stability during hydrothermal treatment at 180^deg;C, have been determined and they are compared to those of Y-TZP and Mg-PSZ materials .     

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.     

A ZrO2 (3Y) Matrix Composite Toughened with Fe3Al Intermetallic

Near fully dense ZrO₂(3Y)/Fe₃Al composites with significantly improved fracture toughness were synthesized by hot-press sintering at 1350°C. High fracture toughness and bending-strength values, 36 MPa·m^1/2 and 1321 MPa, respectively, were achieved in 40 vol% Fe₃Al composite ceramics, whereas those same values for ZrO₂(3Y) alone were 10 MPa·m^1/2 and 988 MPa, respectively. Microscopic observation of the crack path revealed that Fe₃Al particle uniformly dispersed in the matrix have obvious crack-bridging effect. Improved thermal-shock resistance was also obtained, which was attributed to higher toughness, thermal conductivity, and lower Young's modulus by adding of Fe₃Al particles.     

硫氰酸铵滴定液(0.1 mol/L)不确定度评定

分析硫氰酸铵滴定液(0.1 mol/L)不确定度,计算各分量不确定度及合成不确定度。将配制好的硫氰酸铵滴定液用已知浓度的硝酸银滴定液进行标定,分析影响测量结果的各种因素,计算得出扩展不确定度为0.0005 mol/L,A类标准不确定度和B类合成标准不确定度分别为0.08%和0.24%。影响B类合成不确定度的主要因素是硝酸银滴定液的浓度不确定度大小。     

Study of [Fe(bpy)3] complex encapsulated in zeolite Y

Tris complex of Fe^II with 2,2′ bipyridine (bpy) ligand, has been encapsulated in the supercages of zeolite Y and characterized by powder X-ray diffraction, Infrared spectroscopy, ⁵⁷Fe Mössbauer, effect measurements and multinuclear NMR spectroscopy. The complex was prepared in the supercages of Zeolite Y by exchanging the cations of zeolite Y with Fe^II and its subsequent complexing with bpy ligand. Based on the comparison of the results obtained for [Fe^II(bpy)₃](ClO₄)₂ and the [Fe(bpy)₃]Y complexes, it has been inferred that there is significant structural distortion for the encapsulated complex and all Fe is present as Fe^II in low spin state, which is characterized by isomer shift, δ = 0.37 mm s⁻¹ and quadrupole splitting, ΔE_q = 0.81 mm s⁻¹ as revealed by ⁵⁷Fe Mössbauer spectroscopic measurements.