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991.
992.
Ⅱ-Ⅵ型量子点制备及其在生物检测中应用研究进展 总被引:9,自引:0,他引:9
Ⅱ Ⅵ型量子点特殊而优良的可见光区荧光性质使得它们在生物识别及检测中具有潜在的应用前景 ,因而引起人们的广泛关注。本文概述了Ⅱ Ⅵ型量子点的制备及其在生物检测中应用的研究进展 相似文献
993.
含树枝状大分子PAMAM的苯乙烯乳液聚合 总被引:1,自引:0,他引:1
将树枝状大分子PAMAM (4 5代 )作为种子 ,以苯乙烯为代表性单体进行乳液聚合 .研究结果表明 ,加入树枝状大分子PAMAM时 ,所制得的聚合物乳液粒子平均粒径在 30~ 5 0nm之间 ,小于 10 0nm ,且大小分布均匀 ;所制备的聚合物在 16 70cm- 1 左右处出现酰胺的特征吸收峰 ,在 330 0cm- 1 左右处出现N—H伸缩振动特征峰 ;说明树枝状大分子PAMAM起到种子的作用 ,所制备的聚合物含树枝状大分子PAMAM . 相似文献
994.
Hui Wu Xiu-mei Chen Ling Ye Hua-hong Xu Li-ling Pang Da-qing Shi 《Tetrahedron letters》2009,50(9):1062-1065
A Tröger’s base derivative (5,12-dimethyl-3,10-diphenyl-1,3,4,8,10,11-hexaazatetracyclo [6.6.1.02,6.09,13]pentadeca-2(6),4,9(13),11-tetraenes) was used as an efficient catalyst for the three-component Mannich reactions of aromatic aldehydes and aromatic amines with ketones in water at room temperature. This rapid reaction afforded the corresponding β-amino ketones in good yields with excellent stereoselectivity. 相似文献
995.
Jing‐Lin Pang Hong‐Bin Xie Shao‐Wen Zhang Yi‐Hong Ding Ao‐Qing Tang 《International journal of quantum chemistry》2009,109(4):801-810
The NCO + C2H4 reaction is simple and prototype for reaction of the NCO radical with unsaturated hydrocarbons, and it is considered to be important in fuel‐rich combustion. In this article, we for the first time perform detailed theoretical investigations for its reaction mechanism based on Gaussian‐3//B3LYP scheme covering various entrance and decomposition channels. The most favorable channel is firstly the NCO and C2H4 approach each other, forming a weakly‐bound complex L1 OCN···C2H4, followed by the formation of isomer L2 OCNCH2CH2 via a small barrier of 1.3 kcal/mol. Transition states of any decomposable or isomeric channels for L2 in energy are much higher than reactants, which indicate that adduct L2 has stabilization effect in this NCO + C2H4 reaction. The direct H‐abstraction channel leading to P1 HNCO + C2H3, might have an important contribution to the eventual products in high temperature. These results can well explain available kinetic experiment. Moreover, reaction mechanism for the title reaction is significantly different from the NCO + C2H2 reaction which proceeds on most favorably to generate the products HCN + HCCO and OCCHCN + H via a four‐membered ring intermediate. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 相似文献
996.
998.
A viral disease model with saturated contact rate is introduced and investigated. The model consists a host species, which is divided into two classes the susceptible and infected, and a virus, which causes a viral disease in the host and as the host induces, the infected releases more virus into the environment. Taking the virus replication rate as the bifurcating parameter, we prove that there exists a threshold value beyond which the endemic equilibrium bifurcates from the free disease one. Further increasing the value, the endemic equilibrium loses its stability, Hopf bifurcation occurs and a periodic solution arises from it. The orbital stability of the periodic orbits is analyzed by applying Poore’s condition. In the last, numerical simulation of the model is employed to explain the mathematical results of this paper. 相似文献
999.
1000.
In the first part of this paper, we establish several sensitivity results of the solution x(t, ξ) to the ordinary differential equation (ODE) initial-value problem (IVP) dx/dt = f(x), x(0) = ξ as a function of the initial value ξ for a nondifferentiable f(x). Specifically, we show that for $\Xi_T \equiv \{\,x(t,\xi^0): 0 \leq t \leq T\,\}$ , (a) if f is “B-differentiable” on $\Xi_T$ , then so is the solution operator x(t;·) at ξ0; (b) if f is “semismooth” on $\Xi_T$ , then so is x(t;·) at ξ0; (c) if f has a “linear Newton approximation” on $\Xi_T$ , then so does x(t;·) at ξ0; moreover, the linear Newton approximation of the solution operator can be obtained from the solution of a “linear” differential inclusion. In the second part of the paper, we apply these ODE sensitivity results to a differential variational inequality (DVI) and discuss (a) the existence, uniqueness, and Lipschitz dependence of solutions to subclasses of the DVI subject to boundary conditions, via an implicit function theorem for semismooth equations, and (b) the convergence of a “nonsmooth shooting method” for numerically computing such boundary-value solutions. 相似文献