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81.
Chengzhe Zhao Guangfeng Wu Chao Zhou Haidong Yang Huixuan Zhang 《Journal of Polymer Science.Polymer Physics》2006,44(4):696-702
A series of acrylic impact modifiers (AIMs) with different particle sizes ranging from 55.2 to 927.0 nm were synthesized by seeded emulsion polymerization, and the effect of the particle size on the brittle–ductile transition of impact‐modified poly(vinyl chloride) (PVC) was investigated. For each AIM, a series of PVC/AIM blends with compositions of 6, 8, 10, 12, and 15 phr AIM in 100 phr PVC were prepared, and the Izod impact strengths of these blends were tested at 23 °C. For AIMs with particle sizes of 55.2, 59.8, 125.2, 243.2, and 341.1 nm, the blends fractured in the brittle mode when the concentration of AIM was lower than 10 phr, whereas the blends showed ductile fracture when the AIM concentration reached 10 phr. It was concluded that the brittle–ductile transition of the PVC/AIM blends was independent of the particle size in the range of 55.2–341.1 nm. When the particle size was greater than 341.1 nm, however, the brittle–ductile transition shifted to a higher AIM concentration with an increase in the particle size. Furthermore, the critical interparticle distance was found not to be the criterion of the brittle–ductile transition for the PVC/AIM blends. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 696–702, 2006 相似文献
82.
Yan Zhao Xingbin Yang Ru Jiang Xiaoli Sun Wenmin Liu Shengyong Zhang 《Analytical sciences》2006,22(5):747-751
The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory. 相似文献
83.
Y. Zhao W.C. Zhai W.L. Seah K.Y. Lim F.C. Cheong C.H. Sow 《Applied physics. B, Lasers and optics》2007,87(2):243-247
A study of the variation of the spectral shape and the harmonic distribution of the high-order harmonics generated from silver
plasma on the frequency chirp of the driving laser radiation (793 nm 48 fs) is reported. The results of the systematic study
of the harmonic generation from the 21st order up to the 61st order (λ=13 nm) are presented. A tuning of the harmonic wavelength
up to 0.8 nm can be accomplished by variation of the laser chirp.
PACS 42.65.Ky; 42.79.Nv; 52.38.Mf 相似文献
84.
Hong Bi Qianwang Chen Yonglong Zhuang Shenqiang Zhao 《Journal of magnetism and magnetic materials》2006
Molecular magnet {NBu4[Fe Cr(ox)3]}x (NBu4+=tetra(n-buty1) ammonium ion; ox2−=oxalate ion) was synthesized under an applied low magnetic field of 0.3 T in comparison to that synthesized without a field. Their crystallinities, morphologies and magnetic properties were characterized by using the X-ray diffractionmeter, the transmission electron microscope, and a superconducting quantum interference device. It is found that the average size of particles synthesized under the applied field appears larger than that synthesized without a field. Moreover, its crystallinity, morphology and magnetic susceptibility have also been improved. However, its chemical structure and ferromagnetic phase transition temperature Tc do not change. Possible reasons to explain this effect are also discussed. 相似文献
85.
86.
本文介绍了一种新的自动调焦方法准直小孔法.对自动调焦的原理和后继电路处理方法作了详细的分析.它具有响应时间短、灵敏度高,能够很好的在激光直接写入系统中克服物镜工作台运动中导轨的不平和轴向窜动所造成的离焦。 相似文献
87.
The influence of interdiffusion on eigenstates in an interdiffusion-induced GaAs/AlxGa1-xAs single-quantum-well structure is analysed numerically by the finite element method. In this approach, the confinement potential profile of the interdiffused quantum well structure is nonlinear and is modelled by an error function and, in particular, the nature of the effective mass of an electron is considered. The results show that the number of eigenstates and energy levels varies with the extent of the interdiffusion. Numerical results for the quasi-bound states in the quantum well structure with an applied electric field are also presented. 相似文献
88.
89.
90.
赵晓强 《应用数学学报(英文版)》1990,6(1):40-43
In this paper, we consider nonlinear and nonautonomous systems with the trivial solution:dx/dt=f(t, x), x∈R~nwhere f(t+ω,x)+f(t, x), f(t, 0)=0. By using the theory of Brouwer topological degree, we obtainthe existence theorem of nontrivial ω-periodic solution. Finally the applied example of the theoremis cited. 相似文献