Behaviors of the positive temperature coefficient of resistance of poly(styrene‐co‐n‐butylacrylate) filled with Ni‐plated core‐shell polymeric particles

Conductive composite films of poly(styrene‐co‐n‐butylacrylate) copolymers filled with low‐density, Ni‐plated core‐shell polymeric particles were prepared and their behaviors of positive temperature coefficient of resistance (PTCR) were investigated. When the conductive fillers in the composite film were loaded beyond the critical volume, 10 up to 25 vol %, composite films exhibited a unique electrical resistant transition behavior, which the electrical resistance rapidly increased by several orders of magnitude at the critical temperature. The PTCR transition temperature, in general, occurred before the glass transition temperature of polymer matrix. Further increased the conductive filler loading to 30 vol %, the overpacked conduction paths were formed in the entire composite and the PTCR effects became blurred. While the composite film treated with thermal cycle several times from room temperature up to 120 °C, the electrical resistivity increased accompanied with the shift of the PTCR transition to lower temperature. The reason might have been caused by the formed interfacial cracks within the composite film. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 322–329, 2007     

Concentrated electrolyte solutions at high temperatures and pressures

A survey is given of recent experimental results obtained from high-temperature, high-pressure investigations with water, aqueous solutions, and ionic fluids. Data on the static dielectric constant of water to 550°C and 5 kbar are given and discussed with respect to their relation to water structure. Infrared and Raman spectra of HDO in pure water have been obtained to 400°C and 4 kbar, which give information on hydrogen bonding. Xe–H₂O and CO₂–H₂O mixtures were investigated in the infrared. Ni(II) and Cu(II) complexes were investigated by absorption spectroscopy in aqueous solutions of high chloride content to 350°C and 2–6 kbar. The gas-liquid critical point of ammonium chloride was found at 880°C and 1635 bars. This fluid appears to be predominantly ionic even in the critical region. The possibility of converting pure polar fluids such as ammonia and water into concentrated ionic solutions by self-ionization at very high pressures is mentioned.This paper was presented at the symposium, The Physical Chemistry of Aqueous Systems, held at the University of Pittsburgh, Pittsburgh, Pennsylvania, June 12–14, 1972, in honor of the 70th birthday of Professor H. S. Frank.     

High-resolution laser spectroscopy on H2 at 97–98 nm

A narrowband tunable eXtreme UltraViolet (XUV) laser source is used for a high resolution study of the Lyman (B ¹ _u ⁺ X ¹ _g ⁺ ) band system of molecular hydrogen. Seven rotational transitions of two vibrational bands, (10,0) and (11,0), in the wavelength range from 97.2–98.3 nm have been investigated for the first time under sub-Doppler molecular beam conditions. A calibration procedure using the I₂ standard in the visible yielded an absolute frequency accuracy of 0.02 cm^–1. The obtained H₂ transition frequencies provide a calibration standard in the extreme ultraviolet wavelength region.     

液—液萃取浮选法分离Ni（Ⅱ）,Co（Ⅱ）,Fe（Ⅲ）的研究

研究了在（ＮＨ４）２ＳＯ４存在下，乙醇与水分相的条件。试验表明，丁二酮肟与镍生成的螯合物沉淀可以被萃取浮选在乙醇与水两相之间，钴与丁二酮肟生成的螯合物被乙醇萃取，Ｆｅ（Ⅲ）留在水相中，实现了同一体系中三相分离Ｎｉ（Ⅱ），Ｃｏ（Ⅱ），Ｆｅ（Ⅲ），结果满意。     

Stoichiometric and catalytic methods of asymmetric synthesis of nonproteinogenic α-and β-amino acids via transition metal coordination compounds

The complexes of glycine, -alanine, and -alanine with (S)-[N-(N-benzylprolyl)amino] benzophenone formed by Ni(II) and Cu(II) ions and Schiff bases enter into different nucleophilic and electrophilic reactions with the formation of diastereoisomeric complexes which decompose into proteinogenic and nonproteinogenic L-amino acids with a high chemical yield and elevated optical purity (70–90%). Optically pure amino acids can be obtained from diastereoisomerically pure complexes after the complexes are separated by recrystallization of the mixture of diastereoisomeric complexes formed. A new type of interphase catalysts of C-alkylation of achiral Schiff bases was proposed. The catalysts are positively charged Ni(II) and Cu(II) complexes of Schiff bases of chiral diamines. In some cases, these complexes have a higher activity and capacity to execute asymmetric alkylation than traditional chiral interphase catalysts based on cinchonidine.Based on materials in the section report by Yu. N. Belokon' to the 7th European Symposium on Organic Chemistry, ESOC-7.A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1106–1127, May, 1992.     

Oxidation of Styrene to Benzaldehyde Catalyzed by Schiff Base Functionalized Triazolylidene Ni(II) Complexes

Four new Schiff base functionalized 1,2,3-triazolylidene nickel complexes, [Ni-(L₁NHC)₂](PF₆)₂; 3, [Ni-(L₂NHC)₂](PF₆)₂; 4, [Ni-(L₃NHC)](PF₆)₂; 7 and [Ni-(L₄NHC)](PF₆)₂; 8, (where L₁NHC = (E)-3-methyl-1-propyl-4-(2-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenyl)-1H-1,2,3-triazol-3-ium hexafluorophosphate(V), 1, L₂NHC = (E)-3-methyl-4-(2-((phenethylimino)methyl)phenyl)-1-propyl-1H-1,2,3-triazol-3-ium hexafluorophosphate(V), 2, L₃NHC = 4,4′-(((1E)-(ethane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(2,1-phenylene))bis(3-methyl-1-propyl-1H-1,2,3-triazol-3-ium) hexafluorophosphate(V), 5, and L₄NHC = 4,4′-(((1E)-(butane-1,4-diylbis(azanylylidene))bis(methanylylidene))bis(2,1-phenylene))bis(3-methyl-1-propyl-1H-1,2,3-triazol-3-ium) hexafluorophosphate(V), 6), were synthesised and characterised by a variety of spectroscopic methods. Square planar geometry was proposed for all the nickel complexes. The catalytic potential of the complexes was explored in the oxidation of styrene to benzaldehyde, using hydrogen peroxide as a green oxidant in the presence of acetonitrile at 80 °C. All complexes showed good catalytic activity with high selectivity to benzaldehyde. Complex 3 gave a conversion of 88% and a selectivity of 70% to benzaldehyde in 6 h. However, complexes 4 and 7–8 gave lower conversions of 48–74% but with higher (up to 90%) selectivity to benzaldehyde. Results from kinetics studies determined the activation energy for the catalytic oxidation reaction as 65 ± 3 kJ/mol, first order in catalyst and fractional order in the oxidant. Results from UV-visible and CV studies of the catalytic activity of the Ni-triazolylidene complexes on styrene oxidation did not indicate any clear possibility of generation of a Ni(II) to Ni(III) catalytic cycle.     

The Determination of Trace Elements by Flame Atomic Absorption Spectrometry: Effect of the Composition of Standard Solution Matrices

Abstract

The effect of using solution matrices in calibration standards different from those employed for the extraction steps in the determination of Cd, Cr, Cu, Ni and Zn were tested. Cu and Zn are little affected by matrix effects but, if the extractant is ammonium acetate, the use of other matrices may result in too high Cd, Cr and Ni values.     

激光诱导Ni等离子体发射光谱的空间演化特性研究

在350- 600nm 波长范围内测定了激光烧蚀Ni等离子体中Ni原子的空间分辨发射光谱.测定了385.83 nm发射光谱线的相对强度和STARK展宽及其随径向的变化特性。结果表明, 在沿激光束方向上, 当距离靶表面0-2.5mm范围内变化时,谱线的STARK展宽和谱线的强度都随距靶面距离的增大先增大,但增大到最大值后随距离的进一步增大而减小。谱线强度和STARK加宽的最大值都出现在离靶面约1.5mm处。     

密度泛函理论研究Nin,Nin±(n=1-5)团簇的结构和电子性质

采用基于密度泛函理论的第一性原理方法系统研究了中性及带电Ni小团簇的基态几何结构和电子结构特性。对中性Nin(n=1-5)团簇,除去一个电子对基态几何结构所引起的变化相比增加一个电子所引起的影响要更加明显。n=4时,Ni+4,Ni4以及Ni4-较之相邻个体具有较大的能隙,但在所讨论的尺寸范围内,没有找到幻数结构。随着原子数的递增,Nin+,Nin,Nin-(n=1-5)团簇体系的磁矩总体呈上升趋势,值得关注的是：添加一个电子能够显著增强中性体系的磁性。 讨论了与实验结论符合较好的绝热电子亲和能（AEAs）以及绝热离化势（AIPs）。     

Nin(n=1-9)小团簇的密度泛函理论研究

采用密度泛函理论(DFT)方法对Nin(n=1-9)团簇的结构, 稳定性和磁性进行了详细的研究. 得到了一些以前文献中没有提到的稳定结构, 并与其它方法得到的结构进行了比较, 得到的最稳定结构与实验结果相一致. 团簇能量的二阶差分、分裂能、HOMO-LUMO能隙随团簇尺寸的演化都没有表现出明显的奇偶振荡行为, 但在n=5、7时均有较大的值, 说明相对应的团簇具有较高的稳定性、较低的化学活性. 团簇磁性的研究表明团簇的平均每原子磁矩随团簇尺寸的增加有一定振荡, 但有逐渐减小的趋势, n≥5时团簇的构型对团簇磁性的影响较小.