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161.
测定了四元体系ErCl3-CdCl2-HCl-H2O(298.15K)的相平衡溶度数据, 绘制了相应的溶度图. 该四元体系是由4 个固相区CdCl2·H2O(原始盐)、9CdCl2·2ErCl3·29H2O、CdCl2·7ErCl3·42H2O、ErCl3·6H2O(原始盐)组成的复杂
体系. 对两个新物相化合物9CdCl2·2ErCl3·29H2O 和CdCl2·7ErCl3·42H2O 进行了XRD、TG-DTG 和荧光光谱研究.结果表明, 两个新物相化合物均具有荧光和上转换发光性能; 化合物9CdCl2·2ErCl3·29H2O通过3 步失去其结晶水, CdCl2·7ErCl3·42H2O 则1 步失去其结晶水. 相似文献
162.
壳聚糖季铵盐/滤纸复合膜对胆红素的吸附研究 总被引:11,自引:0,他引:11
用2,3-环氧丙基三甲基氯化铵对壳聚糖进行化学修饰,在壳聚糖的分子结构中引入季胺盐基团,提高其阳离子含量。将壳聚糖季铵盐涂在滤纸上,用戊二醛交联,制得壳聚糖季铵盐/滤纸复合膜,考察该复合膜的强度以及对胆红素的吸附性能。实验结果表明,壳聚糖季铵盐/滤纸复合膜具有良好的力学性能;对胆红素的吸附在3h基本达到平衡,其吸附量远大于壳聚糖/滤纸复合膜;适当取代度及高交联度的复合膜吸附效果较好。复合膜对胆红素的吸附量随离子强度的增加而降低;血清白蛋白的加入使吸附量下降。 相似文献
163.
Excess Molar Volume and Viscosity of Isobutyric Acid + Water Binary Mixtures Near and Far Away from the Critical Temperature 总被引:1,自引:0,他引:1
The excess molar volume VE, shear viscosity deviation Δη and excess Gibbs energy of activation ΔG∗E of viscous flow have been investigated by using density (ρ) and shear viscosity (η) measurements for isobutyric acid + water (IBA+W) mixtures over the entire range of mole fractions at five different temperatures,
both near and close to the critical temperature (2.055K ≤ (T−Tc)≤ 13.055K). The results were also fitted with the Redlich–Kister equation. This system exhibited very large negative values
of VE and very large positive values of Δη due to increased hydrogen bonding interactions and correlation length between unlike molecules in the critical region and
to very large differences between the molar volumes of the pure components at low temperatures. The activation parameters
ΔH∗ and ΔS∗ have been also calculated and show that the critical region has an important effect on the volumetric properties. 相似文献
164.
Thomas Bernert 《Journal of solid state chemistry》2006,179(3):849-854
Cu2MnGeS4 crystallizes orthorhombic in a wurtzite superstructure type while Cu2MnSnS4 crystallizes in a tetragonal sphalerite superstructure type. Lattice constants and thermal analyses of the solid solution series Cu2MnGexSn1−xS4 are presented. A two-phase region is found from Cu2MnGe0.3Sn0.7S4 to Cu2MnGe0.5Sn0.5S4. The cell volume of the mixed crystals increases with increasing Sn content. The melting points increase smoothly with increasing Ge content to x=0.5 and then steeply for higher Ge contents. The single crystal X-ray structure analysis of Cu2MnGe0.55Sn0.45S4 is presented. The refinement converges to R=0.0270 and wR2=0.0586, Z is 2. The volumes of the tetrahedra [MS4] (M=Cu, Mn, Ge, Sn) are calculated. From these volumes the differences in size of the tetrahedra are derived and compared with the corresponding differences in the end members of the solid solution series. It turns out that the resulting structure type in these materials depends on the volume differences of the constituting tetrahedra [MS4]. 相似文献
165.
Transport of oil and gas-condensate mixtures of various compositions is found to be accompanied by a slight increase in viscosity in the coldest period when ground temperatures at depth of a condensate pipeline reach 0 – minus 4°С. Fall in temperature of oil fluids under study to minus 10 – minus 30°С is accompanied by a sharp increase in all structural and rheological parameters of the mixture. Even a slight amount of oil added to a gas-condensate mixture causes a significant decrease in viscosity in the negative temperature range. As a result, cloud and pour point of a mixture falls, its amount decreases, the structure of paraffin deposits changes. 相似文献
166.
Jima Chandran Laetitia Shintu Stefano Caldarelli 《Magnetic resonance in chemistry : MRC》2014,52(11):694-698
The detailed characterization of complex mixtures by NMR is often hampered by the presence of signals from uninformative compounds, the resonances of which overlap with those of the molecules of interest. We provide here a proof of principle for an approach to NMR signal suppression in complex samples using Molecularly Imprinted Polymers (MIPS). Addition of a few milligrams of polymer to a solution traps the target molecule in typical micromolar to millimolar concentration, thus achieving in situ signal suppression, without altering any other spectral features. This method minimized any manipulation or perturbation of the spectrum and was applied to a complex mixture of known compounds and to a plant extract, in both cases spiked with a compound (bisphenol A), which was subsequently removed by selective binding to a complementary MIP. What is described in this report is comparable with microextraction and may in due course be applied to a large number of analytical challenges. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
167.
Hong-Yong Zhao Yi-Ming Cao Xiao-Li Ding Mei-Qing Zhou Quan Yuan 《Journal of membrane science》2008,310(1-2):365-373
A series of copolymers containing ether oxygen groups and amino groups were prepared based on N,N-dimethylaminoethyl methacrylate (DMEMA) and polyethylene glycol methyl ether methyl acrylate (PEGMEMA). The effect of PEGMEMA content in the copolymer on density, free volume, mechanical performance, and H2, CO2, N2 and CH4 gas transport properties of the copolymer was determined. Free volume was characterized using the polymer density and group contribution theory. The permeability of the copolymer to CO2 is high, and both the CO2/N2 and CO2/H2 selectivities are high. For example, the permeability coefficient of PDMAEMA–PEGMEMA-90 (“90” represents the weight percent of PEGMEMA) to CO2 is 112 Barrer and the CO2/N2 and CO2/H2 selectivity coefficients are 31 and 7, respectively. The effect of the temperature on gas transport properties was also determined. Finally, the potential application of the copolymer membranes for CO2/light gases separation was explored. 相似文献
168.
Guo-xiang Xu Lu Qi Bi-tao Yu Lei Wen Department of Applied Chemistry College of Chemistry Molecular Engineering Peking University Beijing China Department of Inorganic Nonmetal Materials School of Materials Science Engineering University of Science Technology Beijing Beijing China 《高分子科学》2006,(3):307-313
PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by infrared spectrum. 2SPVC's specific area is 36.1 m2·g-1 tested by stand BET method, and granularity experiment gives out the particle size of d0.5= 11.3μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and particle shape of 2SPVC were observed. Cyclic voltammetry (scan rate: 0.5 mV·s-1) shows that 2SPVC experience an obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium battery in a 1 mol·L-1 solution of lithium bis(trifluoromethylsulfonyl) imide (Li(CF3SO2)2N) in a 5:45:50 volume ratio mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is about 400.3 mAh·g-1 which is very close to its theoretical value (410.5 mAh·g-1) at a constant discharge current of 15 mA·g-1. It can retain at about 346.1 mAh·g-1 of discharge capacity after 30 charge-discharge cycles. So 2SPVC is a very promising cathode candidate for rechargeable lithium batteries. 相似文献
169.
S. Sridhar B. Smitha A. Amarnath Reddy 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,280(1-3):95-102
Blend membranes of poly(vinyl alcohol) (PVA) and nylon 66 (NYL) were synthesized and crosslinked with glutaraldehyde (GA) and assessed for their suitability in dehydrating 2-butanol by pervaporation (PV). These blends were subjected to sorption studies to determine the extent of interaction and degree of swelling in pure liquids as well as binary mixtures. Wide-angle X-ray diffraction (WAXD) and thermal gravimetric analysis (TGA) were carried out to investigate changes in crystallinity and thermal stability, respectively. The effect of experimental parameters such as feed water concentration, permeate pressure and barrier thickness on membrane flux and selectivity was evaluated. The membranes were found to have good potential for breaking the azeotrope of 27.6 wt.% water with a flux of 3.07 kg/m2 h 10 μm and selectivity of 26.5. Selectivity was found to improve with decreasing feed water concentration and increasing membrane thickness, whereas opposite trends were observed in case of flux. Higher permeate pressure caused a reduction in both flux and selectivity. These effects were clearly elucidated. 相似文献
170.
有关Co(Ⅱ)、Ni(Ⅱ)萃取分离的研究一直受到人们的重视。Preston报导了硫氰酸季铵盐(Q~ SCN-)萃取Co(Ⅱ)、Ni(Ⅱ)的平衡研究,认为Co(Ⅱ)的萃合物组成为Q_2Co(SCN)_4.本文用上升液滴法技术考察了Co(Ⅱ)/0.10mol·L~(-1)SO_4~(2-)/QSCN-煤油体系在298±1K条件下萃取速率R与CoSO_4、SO_4~(2-)和QSCN浓度的关系,确定了正向初始萃取速率方程,拟定了速控步骤。 相似文献