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采用以碘酸基为末端基的聚氧乙烯(PEO)接枝聚醚氨酯和氨基酸反应,将赖氨酸(Lys)和酪氨酸(Tyr)通过PEO为“间隔臂”固定在聚醚氨酯上,制备了氨基酸和PEO复合修饰的聚醚氨酯PEU-g-PEO-SO2Lys和PEU-g-PEO-SO2Tyr。通过血小板粘附试验对材料的体外抗凝血性进行 了初步评价。研究结果表明,采用具有选择性吸附纤溶酶原功能的赖氨酸和PEO复合修聚氨酯,不仅减少了材料表面血小板粘附量,而且减少了材料表面栓的形成量。 相似文献
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In this paper, under assumption that tempeature is linearly distributed along the thickness of the shell, we deal with problems as indicated in the title and obtain general solutions of them which are expressed in analytic form.In the first part, we investigate free vibration of circular shallow spherical shells with circular holes at the center under usual arbitrary boundary conditions. As an example, we calculate fundamental natural frequency of a circular shallow spherical shell whose edge is fixed (m=0). Results we get are expressed in analytic form and check well with E. Reissner’s [1]. Method for calculating frequency equation is recently suggested by Chien Wei-zang and is to be introduced in appendix 3.In the second part, we investigate forced vibration of shells as indicated in the title under arbitrary harmonic temperature field and arbitrary harmonic dynamic normal load.In the third part, we investigate forced vibration of the above mentioned shells with initial conditions under arbitrary unsteady temperature field and arbitrary normal load.In appendix 1 and 2, we discuss how to express displacement boundary conditions with stress function and boundary conditions in the case m=1. 相似文献
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Recently a new type of experiment, i.e., Bloch oscillations of ultracold atoms in honeycomb optical potential,realized Landau–Zener transition in the vicinity of Dirac point in 2D optical lattice. We show that the slope of Dirac cone is related to the transition probability of Landau–Zener transition. Therefore, it provides a new tool to directly detect the energy spectrum in the vicinity of Dirac point. Moreover, we numerically demonstrate that our scheme is feasible and effective in a large range of the parameter of anisotropy. 相似文献
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In this paper,under assumption that tempeature is linearly distributed along the thickness of theshell,we deal with problems as indicated in the title and obtain general solutions of them which areexpressed in analytic form.In the first part,we investigate free vibration of circular shallow spherical shells with circularholes at the center under usual arbitrary boundary conditions.As an example,we calculate fundamen-tal natural frequency of a circular shallow spherical shell whose edge is fixed(m=0).Results we get areexpressed in analytic form and check well with E.Reissner’s[1].Method for calculating frequencyequation is recently suggested by Chien Wei-zang and is to be introduced in appendix3.In the second part,we investigate forced vibration of shells as indicated in the title under arbitr-ary harmonic temperature field and arbitrary harmonic dynamic normal load.In the third part,we investigate forced vibration of the above mentioned shells with initialconditions under arbitrary unsteady temperature 相似文献
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