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91.
Donghyun Cho Taihyun Chang Apostolos Avgeropoulos Nikos Hadjichristidis 《European Polymer Journal》2003,39(11):2155-2160
Temperature gradient interaction chromatography (TGIC) was applied for the separation of a complex miktoarm star copolymer which has one polystyrene (PS) arm and three polystyrene-b-polyisoprene (PS-b-PI) diblock copolymer arms. Such miktoarm star polymers are much more difficult to characterize than branched homopolymers since the byproduct, typically polymers with missing arm(s) or coupled products, have not only different molecular weights but also different compositions. TGIC was able to fully separate the byproducts, and the composition of the molecular species corresponding to the different separated elution peaks was determined by two methods, fractionation/NMR and multiple detection (UV and RI). A reasonable agreement between the results of the two methods was obtained. By using the composition found, the corresponding molecular weights were determined by multi-angle light scattering detection. Based on the composition and the molecular weight we were able to identify the structure of the different molecular species. 相似文献
92.
Anna L. Mazzucato 《Transactions of the American Mathematical Society》2003,355(4):1297-1364
This paper is devoted to the analysis of function spaces modeled on Besov spaces and their applications to non-linear partial differential equations, with emphasis on the incompressible, isotropic Navier-Stokes system and semi-linear heat equations. Specifically, we consider the class, introduced by Hideo Kozono and Masao Yamazaki, of Besov spaces based on Morrey spaces, which we call Besov-Morrey or BM spaces. We obtain equivalent representations in terms of the Weierstrass semigroup and wavelets, and various embeddings in classical spaces. We then establish pseudo-differential and para-differential estimates. Our results cover non-regular and exotic symbols. Although the heat semigroup is not strongly continuous on Morrey spaces, we show that its action defines an equivalent norm. In particular, homogeneous BM spaces belong to a larger class constructed by Grzegorz Karch to analyze scaling in parabolic equations. We compare Karch's results with those of Kozono and Yamazaki and generalize them by obtaining short-time existence and uniqueness of solutions for arbitrary data with subcritical regularity. We exploit pseudo-differential calculus to extend the analysis to compact, smooth, boundaryless, Riemannian manifolds. BM spaces are defined by means of partitions of unity and coordinate patches, and intrinsically in terms of functions of the Laplace operator.
93.
V. Balek T. Mitsuhashi I.M. Bountseva H. Haneda Z. Malek J. Šubrt 《Journal of Sol-Gel Science and Technology》2003,26(1-3):185-189
The diffusion structural analysis (DSA) was used to characterize microstructure changes of hydrous titania gel films under in situ conditions of heating. TG and DTA were used in order to elucidate the processes controlling the formation of anatase film during heating of hydrous titania gel film. The annealing of porosity and near surface structure defects of the dehydrated titania films was indicated by DSA in the temperature range 255–700°C as the decrease of radon release rate. It was demonstrated that the annealing was enhanced on heating in oxygen in comparison with heating in argon. The DSA experimental results were compared with model curves describing the radon diffusion mobility and the annealing of radon diffusion paths. 相似文献
94.
M. Ohsaki 《Archive of Applied Mechanics (Ingenieur Archiv)》2003,73(3-4):241-251
Summary Characteristics of optimal solutions under nonlinear buckling constraints are investigated by using a bar-spring model. It is demonstrated that optimization under buckling constraints of a symmetric system often leads to a structure with hill-top branching, where a limit point and bifurcation points coincide. A general formulation is derived for imperfection sensitivity of the critical load factor corresponding to a hill-top branching point. It is shown that the critical load is not imperfection-sensitive even for the case where an asymmetric bifurcation point exists at the limit point. 相似文献
95.
ZHANG Han-hui LIN Zheng-zhong HUANG Chang-cang SUN Rui-qing WU Xiao-yuan LIN Zhi-hua 《光谱学与光谱分析》2004,(5)
用FTIR ,NIRFT Raman ,UV VisDRS和荧光光谱等对五个新型具有 [(PO4) 4 MoⅤ6O15]12 -阴离子簇的化合物 :Na·(H4TETA) 3 ·(H3 O) 5·{Zn[(HPO4) 2 (PO4) 2 Mo6O15]2 } (2 ) ,(H2 en) 7·(H3 O) 4 ·{Cu[(HPO4) 2(PO4) 2 Mo6O15]2 }·H2 O (3) ,(H3 DETA) 2 ·(H3 O) 3 ·{Co0 5[(HPO4) 2 (PO4) 2 Mo6O15]}·H2 O (4) ,[Co(H3 TETA) ]2 {Co0 5[(HPO4) (PO4) 3 Mo6O15]}· 3 5H2 O (5 )和 (H3 DETA)· (H3 O ) 4 · {Co1 5[(HPO4) 2(PO4) 2 Mo6O15]}·0 5H2 O (6 ) ,进行研究 ,并探讨其结构和性能的关系。这些化合物具有 {M [(PO4) 4 Mo6O15]2 }二聚体单元 ,化合物 2~ 4的二聚体间通过与有机分子和水分子的氢键形成三维网状结构 ;化合物 5和 6的 {Co[(PO4) 4 Mo6O15]2 }二聚体间是分别通过 [CoH3 TEATA]基团和CoO4四面体组成网状结构。磷钼酸盐的特征振动频率和这些化合物的结构相关 ;化合物的三个UV VisDRS特征谱带分别属于Od→Mo,Oμ→Mo和O→M电荷转移 ;观察到以 2 4 0nm激发 ,在 4 10nm附近出现的由Oμ→Mo跃迁激发引起的较强的荧光发射谱带。 相似文献
96.
线性规划联合算法的理论与应用 总被引:6,自引:4,他引:2
本在[1]的基础上.较系统的叙述了线性规划联合算法的步骤、相关理论及其应用,指出该算法具有避免人工变量、减少迭代次数、使用灵活、应用方便等特点。 相似文献
97.
区域经济的发展受许多不同因素的影响,本结合西藏社会经济发展的特点,选取了总产值指标、第一产业指标、第二产业指标和第三产业指标等四大类指标体系,采用灰色关联分析法对西藏的区域经济系统进行了简要的分析评价,以研究西藏区域经济的发展状况,从社会经济的角度探讨西藏经济发展落后的原因,以期能为西藏经济发展政策提供参考依据。 相似文献
98.
M/G/1非空竭服务休假排队系统随机分解的简化算法 总被引:2,自引:0,他引:2
本文根据M/G/1非空竭服务休假排队系统稳态队长随机分解的结构特征提出一种统一算法,该方法简洁高效,避免了再生循环方法繁杂的运算。运用该方法得出的结果与已知的用再生循环方法得出的结论一致。并且修正了Levy(1989)关于Bernoulli闸门服务休假排队系统随机分解的一个错误。 相似文献
99.
100.