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281.
35MeV/u 40 Ar+197 Au反应中热核的碎裂密度 总被引:1,自引:0,他引:1
许多提取核反应过程中熵产生的方法只适用于高能核反应过程 ,而约化d的产额方法可以用于较低能量的重离子核反应中 .对于 3 5MeV/u40 Ar+ 197Au的核反应过程 ,利用这种方法所得的熵和约化带电粒子多重性提取的熵结果一致 .对于后角热核发射体系 ,实验提取的核温度为 ( 4.7± 1 .2 )MeV ,熵为S/A =2 .5± 0 .5,根据实验提取的熵和核温度可以确定其碎裂密度小于 0 .1 ρ0 相似文献
282.
Long‐Mei Zeng Chao‐Jie Wang Jing‐Yu Su Du Li Noel L. Owen Yang Lu Nan Lu Qi‐Tai Zheng 《中国化学》2001,19(11):1097-1100
Two new flavonoids, acanthophorin A (1) and acanthophorin B (2), along with three known compounds tiliroside (3), (‐)‐catechin (4) and quercetin (5) were isolated from the red alga Acanthophora spicifera. The structures of 1 and 2 were determined to be kaempferol 3‐O‐α‐L‐fucopyranoside (1) and quercetin 3‐O‐α‐L‐fucopyranoside (2) by spectroscopic methods. Both 1 and 2 showed significant antioxidant activity. 相似文献
283.
Titanium dioxide semiconductor systems with excellent stability of photo-electric chemistry, no poison, cheap, and high separation efficiency of photogenerated charges, consequently, high photocatalytic activity, have been the subject of extensive investigation because of their promise in the photovoltaic[1], photocatalytic[2], and battery applications[3]. The efficiencies of these materials in photovoltaic and photocatalytic applications depend strongly upon the trapping and recombination energetics, i.e., electrons and holes and the conversion of light. Nanosized TiO2 particles present much higher photocatalytic activity due to larger effective surface areas, higher densities of. surface states, shorter distance of photogenerated charges from inner to the surfaces of TiO2 particles resulting in higher separation efficiency of electron-hole pairs, and quantum size effect. 相似文献
284.
Crystal and molecular structure of (2,6-dipropylphenylamide) dimethyl (tetra-methyl cyclopentadienyl) silane titanium dichloride (I) was fully characterized by X-ray diffraction. The crystal is obtained from a mixture of ether/hexane as orthorhombic, with a = 12.658 (3) (A), b = 16.62 (3)(A), c = 11.760 (2)(A), V = 2474.2 (9)(A) 3, Z = 4, space group Pnma, R = 0.0399. Componud I compose of the π-bounded ring with its dimethylsilyl-dipropyl phenyl amido group and the two terminal chloride atoms coordinated to central metal to form a so-called constrained geometry catalyst (CGC) structure. The result of molecular mechanics (MM) calculations on compound I shows that bond lengths and bond angles from the MM calculation are comparable to the data obtained from the X-ray diffraction study. The relation of the structure of CGCs and their catalytic activity by MM calculations is also discussed. 相似文献
285.
Ronny Pini Giuseppe Storti Marco Mazzotti Hongyun Tai Kevin M. Shakesheff Steven M. Howdle 《Macromolecular Symposia》2007,259(1):197-202
Summary: The equilibrium sorption and swelling behavior in supercritical CO2 of poly(D,L-lactic acid) and poly(lactic-co-glycolic acid) has been studied at a temperature of 35 °C and at pressures up to 200 bar. Sorption was measured through a gravimetric technique and swelling by visualization. From these data, the behavior of the different polymers can be compared. In terms of partial molar volume of CO2 in the polymer matrix, all the polymers exhibit a behavior typical of rubbery systems. The experimental results have been modeled using the Sanchez-Lacombe equation of state, which is able to represent the actual behavior of the polymer-CO2 systems with reasonable accuracy. 相似文献
286.
Chaotic dynamics in systems having many degrees of freedom are investigated from the viewpoint of harnessing chaos and is applied to complex control problems to indicate that chaotic dynamics has potential capabilities for complex control functions by simple rule(s). An important idea is that chaotic dynamics generated in these systems give us autonomous complex pattern dynamics itinerating through intermediate state points between embedded designed attractors in high-dimensional state space. A key point is that, with the use of simple adaptive switching between a weakly chaotic regime and a strongly chaotic regime, complex problems can be solved. As an actual example, a two-dimensional maze, where it should be noted that the set context is one of typical ill-posed problems, is solved with the use of chaos in a recurrent neural network model. Our computer experiments show that the success rate over several hundreds trials is much better, at least, than that of a random number generator. Our functional simulations indicate that harnessing of chaos is one of essential ideas to approach mechanisms of brain functions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
287.
本文讨论了较为广泛的一类函数方程G(x,f(x),f^2(H2(x,f(x)),…,f^n(Hn(x,f(x),…,f^n-1(x))))=0, 对任x∈J.其中n≥,J为实数轴R 的连通闭子集,G∈C^m(J^n 1,R),Hk∈C^m(J^k,R),k=2,…,n.对任一个整数m≥0,本文在较弱的条件下讨论下该方程的C^m解的存在性和惟一性。 相似文献
288.
有界凸圆型域上的准凸映照 总被引:7,自引:1,他引:6
本文研究星形映照的一类子族——有界凸圆型城上的准凸映照,并讨论了它与星形映照及凸映照的关系,建立其与凸映照同形的增长定理和掩盖定理. 相似文献
289.
290.