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251.
采用乙酸乙酯为环型和线型聚苯乙烯的非良溶剂, 确定了Mark-Houwink方程分别为[η]_r=1.91×10~(-2)·M~(0.607)和[η]_l=4.06×10~(-2)·M~(0.572)。研究了环型和线型聚苯乙烯的激基缔合物的荧光效应。通过稀溶液中环型和线型高分子线团在柔顺性上存在着差异, 解释了二者之间在荧光效应方面的差异, 并根据实验结果,确定了(I_E/I_M)c→0~M关系式分别为(I_E/I_M)r,c→0=1.91+3.40×10~(-6)M和(I_E/I_M)l,c→0=2.15+3.05×10~(-6)M。 相似文献
252.
A family of alkaline earth organosulfonate coordination solids is reported. In contrast to more typical crystal engineering approaches, these solids are sustained by the assembly of building blocks that are coordinatively adaptable rather than rigid in their bonding preferences. The ligand, 4,5-dihydroxybenzene-1,3-disulfonate, L, progressively evolves from a 0D, 1D, 2D, to a 3D microporous network with the Group II cations Mg(2+), Ca(2+), Sr(2+), and Ba(2+), (compounds 1-4), respectively. This trend in dimensionality can be explained by considering factors such as hard-soft acid-base principles and cation radii, a rationalization which follows salient crystal engineering principles. The selective gas sorption properties of the microporous 3D network [Ba(L)(H(2)O)].H(2)O, 4, with different gaseous guests are also presented. 相似文献
253.
C. K. Radhakrishnan A. Sujith G. Unnikrishnan 《Journal of Thermal Analysis and Calorimetry》2007,90(1):191-199
The thermal behaviour of styrene butadiene rubber (SBR)/poly (ethylene-co-vinyl acetate) (EVA) blends was studied by using
thermogravimetry (TG) and differential scanning calorimetry (DSC). The effects of blend ratio, cross-linking systems and compatibilization
on the thermal stability and phase transition of the blends were analyzed. It was found that the mass loss of the blends at
any temperature was lower than that of the components, highlighting the advantage of blending SBR and EVA. The addition of
compatibilizer was also found to improve the thermal stability. DSC studies indicated the thermodynamic immiscibility of SBR/EVA
system even in the presence of the compatibilizer. This is evident from the presence of two different glass transition temperatures,
corresponding to SBR and EVA phases in both compatibilized and uncompatibilized blends. 相似文献
254.
Bohumír Grüner Jaroslav Ba?kovský Bohumil Štíbr 《Journal of organometallic chemistry》2005,690(11):2850-2852
The compounds with a single and double -CH2C6H4CH2- spacer, [CpFeC3B8H10-NH-CH2C6H4CH2-NH-C3B8H10FeCp] and [CpFeC3B8H10-N-(CH2C6H4CH2)2-N-C3B8H10FeCp], represent the first example of designed shaping by extremely stable cyclopentadienyl-ferratricarbollide (CpFeTCB) cages into rigid molecular constructions approaching linear arrangement. 相似文献
255.
最小一乘稳健多元分析校正 总被引:1,自引:3,他引:1
本文论述最小一乘求解的多元分析校正算法,探讨了最小一乘较常规最小二乘法及其他隐健算法的优点。用计算机数值模拟及实际多组分光谱体系对方法进行了检验,展示了最小一乘法在分析化学计量学中实际应用的可行性。 相似文献
256.
We demonstrate that ferroelectric liquid crystals dispersed in a polymer matrix can form uniaxially aligned elliptical droplets. The alignment is controlled by mechanical shear during the polymerization of a UV-curable adhesive. The possibility of prealignment makes polymer-dispersed ferroelectric liquid crystals suitable for application in flexible electro-optical displays. In contrast to surface stabilized ferroelectric liquid crystal displays, the electro-optical effect in our system is due to the deformed-helix ferroelectric (DHF) effect. 相似文献
257.
Yossef A. Elabd Marco Giacinti Baschetti Timothy A. Barbari 《Journal of Polymer Science.Polymer Physics》2003,41(22):2794-2807
Over the past 2 decades, the use of time‐resolved Fourier transform infrared/attenuated total reflection (ATR) spectroscopy for the measurement of diffusion in polymers has grown. ATR is a powerful technique for the measurement of diffusion in polymers because it is an in situ technique that is relatively inexpensive, provides reliable short‐time data, and provides a wealth of information at the molecular level. This article highlights the technique and its application to numerous studies, ranging from the diffusion of drugs in human skin to chemical warfare agents in barrier materials. In addition to these topics, recent studies with ATR to quantify and model molecular interactions during the diffusion process are reviewed. In the future, the ATR technique may have an impact on a variety of emerging fields in which diffusion in polymers plays an important role, such as fuel cells, membrane separation, sensors, and drug delivery. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2794–2807, 2003 相似文献
258.
Effect of the type and number of high-speed impellers installed on a common shaft on the power characteristics was investigated
in water and glucose solutions of different concentration. Different configurations of the Rushton or Smith turbines, pitched
blade turbines, propeller, and A 315 impeller were tested. Measurements of power consumption were carried out within the transitional
and turbulent regime of the fluid flow using the strain gauge method. Baffled agitated vessels with inner diameter of 0.288
m and 0.634 m were used for the experiments. Liquid height in the vessels was equal to the vessel diameter or it was twice
higher. The relative power consumption was compared for different configurations of the impellers.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
259.
The evaluation of matrix elements of two electron atoms is fundamental for the study of the electronic properties of those systems. We add to this knowledge by presenting an explicit expression for the matrix elements of the inverse of the interelectronic distance of two-electron atoms in any spatial dimension D. The basis functions used are the D-dependent hydrogenic wavefunctions {1s
2,2p
2,3d
2,4f
2,5g
2,...,21y
2,...}, extending and including, in this way, the results of the previous basis set {1s
2,2p
2,3d
2,4f
2}. The methodology used does not employ Fourier integral transforms as in previous works but hypergeometric transformation formulas. 相似文献
260.
Summary Ten pesticides have been completely separated by two-dimensional (2D) development on TLC plates coated with coupled layers
of octadecyl silica (reversed-phase, RP) and plain silica (normal-phase, NP). The binary mobile phases, aqueous-organic for
RP chromatography and nonaqueous for NP chromatography, were chosen from plots ofR
F against mobile-phase composition and graphicalR
F(RP)-R
F(NP) correlations. The different selectivity of the RP and NP systems enabled dispersion of spots over the plate area and good
separation. 相似文献