氯化钕异丙醇合物/三异丁基铝催化剂活性中心的分离与聚合

研究了氯化钕异丙醇合物/三异丁基铝催化剂的配制方式对异戊二烯聚合和聚合产物特性的影响。 将催化剂的悬浊液分离得到清液和沉淀，分别进行聚合，并对沉淀进行了拉曼光谱表征。 结果表明，(Nd+Al)配制方式在室温和70 ℃下所得催化剂的清液均无活性，并且70 ℃下所得催化剂的沉淀也无活性。 (Nd+IP+Al)配制方式在任何条件下所得催化剂的各组分均有活性，推测该配制方式所得催化剂可能形成的是2种活性中心：(isoprenyl)2NdCl和(isoprenyl)NdCl2。 配制方式对聚异戊二烯的微观结构没有影响(96%左右)，分离前的悬浮催化剂和沉淀催化剂所得聚异戊二烯均为高分子量(Mn＞100×104)和窄分子量分布(Mw/Mn＜2.0)的聚合物，但是分离后清液所得聚合物的分子量较低(Mn＜30×104)，分子量分布很宽(Mw/Mn＞5.0)。     

An integrated solution and analysis of bioluminescence tomography and diffuse optical tomography

While diffuse optical tomography (DOT) has been studied for years, bioluminescence tomography (BLT) is emerging as a promising optical molecular imaging tool. These two modalities have different goals. DOT is for reconstruction of optical parameters of a medium such as a breast from surface measurements induced by external sources. BLT is for reconstruction of a bioluminescent source distribution in a medium such as a mouse from surface measurements induced by internal bioluminescent sources. However, an important pre-requisite for BLT reconstruction is the knowledge on the distribution of optical parameters within the medium, which is the output of DOT. In this paper, we propose a mathematical model integrating BLT and DOT at the fundamental level; that is, performing the two types of reconstructions simultaneously instead of doing them sequentially. The model is introduced through minimizing the difference between predicted quantities and boundary measurements, as well as incorporating regularization terms. Then, we show the solution existence, introduce numerical schemes and prove convergence of the numerical solution. We also present numerical results to illustrate the utility of our approach.     

高聚物熔体的新状态方程

1引言随着国民经济的快速发展，作为新型的、具有特殊功能的高分子聚合物已成为在国民经济各部门中应用最为广泛的新型材料之一，如SAN、PP、PVC等高聚物．高聚物状态方程是研究这类新型材料性能及其加工过程，以及生产这些高聚物机械设备设计的重要依据，长期以来一直为广大高分子科技工作者十分重视的研究领域。但由于高聚物具有其特殊且又十分复杂的物质结构，与常规的气、液等物态有着很大的差异，尤其热物性与这些常规物质间存在着很大的不同，因此研究起来往往十分困难，至今为止国外的研究仍寥寥无几，国内在这方面的研究几乎尚…     

Quantitative error estimates for coefficient idealization in linear elliptic problems

We give a thorough quantitative error analysis for the effect of coefficient idealization on solutions of linear elliptic boundary value problems. The a posteriori error estimate is derived by a tactful application of the duality theory in convex analysis. The estimate involves an auxiliary function subject to certain constraint. We discuss in detail the selection of a good auxiliary function for various cases. Numerical examples show the effectiveness of our a posteriori error estimate.     

单层介质膜保偏全反射直角三棱镜镀膜材料的选择及其微分相位特性研究

入射角、基底玻璃折射率、膜介质折射率、膜厚等因素会影响单层介质膜保偏全反射直角三棱镜的保偏特性，且各因素的影响程度并不相同。本文分析了上述各因素的微小变化对保偏特性的影响，并提出了选择膜介质的方法     

新型衬底晶体LiGaO2的生长和结晶性质研究

氮化物长期以来被看作是在蓝光及紫外波段光电子应用中最有希望的材料[1].但在改进材料质量方面最大的困难是:缺乏一种能和GaN在晶格及热性能方面十分匹配的理想衬底材料[2].Al2O3被普遍认为可以作为GaN的衬底材料.这主要是由于它具有的结构、热性能好,和生长加工容易等特点.     

The monoid of strong endomorphisms of a graph

We explicitly find all the idempotents in eachL(R)-class and all the inverses of each element of the strong endomorphism monoid of a graph. The number of these idempotents and inverses is also obtained. The author is deeply indebted to Professor Dr. T. E. Hall for his stimulating questions about this theme and much improvement made to an earlier version of this paper. The author would like to thank Professor Dr. U. Knauer and Dr. E. Wilkeit for helpful comments.