氮氟双掺杂TiO_2纳米管的制备、表征和光催化性能研究——暑期科研训练实验实例

在南开大学化学学院本科生的暑期科研训练中,开展"氮氟双掺杂TiO_2纳米管的制备、表征和光催化性能研究"综合实验,以水热法制备的钛酸纳米管为前驱体,通过含氟化铵的钛溶胶对纳米管进行浸渍修饰,制备氮氟双掺杂的TiO_2纳米管,采用透射电镜、X射线衍射、TG-DTA、XPS、紫外漫反射等手段表征所得材料,以甲基橙溶液模拟有机废水,研究催化剂在紫外及模拟日光下的催化降解性能。通过贴近科研前沿的实验内容,对学生进行系统的初步科研培训,培养学生的综合科研能力。     

精准扶贫视角下湖南省贫困治理绩效评价研究

构建湖南省贫困治理评价指标体系,运用湖南省51个扶贫开发重点县2014-2017年数据,对湖南省贫困治理绩效进行实证分析,实证分析结果显示:湖南省精准扶贫的贫困治理绩效显著,但减贫边际效应递减;精准扶贫具有缩小贫富差距、改善贫困人口生活条件、促进贫困地区公共服务发展的突出效果.在此基础上,对湖南省的精准扶贫目标完成进度进行评估,评估结果为:在原有扶贫政策措施作用下,依照湖南省2014-2017年的减贫速度,湖南省2020年精准扶贫的预期目标可基本完成,贫困发生率和农民人均可支配收入两个目标甚至可以提前完成.但消除绝对贫困的目标任重道远,预计2020年仍有百万农村人口处于贫困状态.     

Interlaboratory quality audit program for potable water – assessment of method validation done on inductively coupled plasma atomic emission spectrometer (ICP-AES)

In an effort to assess the method validation done using ICP-AES in our laboratory for potable water, an Environmental Laboratory Approval Program organized by New York State Department of Health, Wadsworth Center providing the reference material has been undertaken for 14 trace elements and seven other chemical constituents. The certified means for the reference material and the results obtained in our laboratory are compared. The comparisons helped us assess the quality of our work. All the data from the inductively coupled plasma atomic emission spectrometer (ICP-AES) fall into the ranges specified. These data are intended to depict the quality of chemical analysis being conducted in our laboratory and to increase the level of confidence of our clientele in accepting our test reports. It should be further noted that while the technique may not be new, the model is new and the simultaneous detection of elements required validation for those of our clientele who are only familiar with sequential AAS and AES. Received: 3 April 2002 Accepted: 4 September 2002     

Isomorphisms Between Groups of Homeomorphisms

We give simple conditions which ensure that the topological structure of a manifold is completely determined by a group of homeomorphisms. The reasonings are still valid in the smooth category.     

Gheorghe Ţiţeica and the origins of affine differential geometry

We describe the historical and ideological context that brought to the fore the study of a centro-affine invariant that subsequently received much attention. The invariant was introduced by ?i?eica in 1907, and this discovery has been viewed by many as a consequence of Klein's Erlangen program. We thus present the starting point of affine differential geometry, as it was discovered by ?i?eica after his years in the Ph.D. program in Paris (1896–1899) under the guidance of Gaston Darboux.     

图形软件与量化软件联合用于创建大环分子计算模型

通过实例介绍了将图形软件与量子化学计算软件联合用于创建大环分子量化计算模型的探索结果和操作步骤，为提高大环分子理论研究的工作效率提供了新的方法。     

Public Disclosure Programs vs. traditional approaches for environmental regulation: Green goodwill and the policies of the firm

A Public Disclosure Program (PDP) is compared to a traditional environmental regulation (exemplified by a tax/subsidy) in a simple dynamic framework. A PDP aims at revealing the environmental record of firms to the public. This information affects its image (goodwill or brand equity), and ultimately its profit. A firm polluting less than its prescribed target would win consumer’s sympathy and raise its goodwill, whereas it is the other way around when the firm exceeds its emissions quota. The evolution of this goodwill is assumed to depend also on green activities or advertising expenditures. Within this framework, we analyze how a PDP affects the firm’s optimal policies regarding emissions, pricing and advertising as compared to a traditional regulation. We show that advertising acts as a complementary device to pricing and that emissions are increasing in goodwill. The role of a standard or target level for emissions turns out to be totally different under both policy regimes. In the case of a tax/subsidy approach, this target level only acts as constant who increases or decreases profit by a fixed amount, but it does not affect the policy of the firm. On the contrary, if a PDP is implemented, the target value for emissions enters in an important way in the goodwill accumulation mechanism and determines how the firm reacts to the regulation and what is the time path for the economic and environmental variables. Moreover, this value is also crucial to determine the possibility that a PDP is profit improving. A policy implication of this fact is that regulators should be particularly careful in fixing the emission standard when a PDP is applied. The theoretical results are complemented with a numerical illustration.     

GJ-341小型遥控光电经纬仪星库星表

本文讨论了星体理论值的计算,并给出了计算程序.     

A nonlinear equation for linear programming

We present a characterization of the normal optimal solution of the linear program given in canonical form max{c ^tx: Ax = b, x 0}. (P) We show thatx ^* is the optimal solution of (P), of minimal norm, if and only if there exists anR > 0 such that, for eachr R, we havex ^* = (rc – A^t_r)₊. Thus, we can findx ^* by solving the following equation for _r A(rc – A^t_r)₊ = b. Moreover,(1/r) _r then converges to a solution of the dual program.On leave from The University of Alberta, Edmonton, Canada. Research partially supported by the National Science and Engineering Research Council of Canada.     

Perkin—Elmer公司DSC-2C差示扫描量热仪数据处理站的改进与功能扩展

介绍了对Ｐｅｒｋｉｎ－Ｅｌｍｅｒ公司生产的ＤＳＣ－２Ｃ差示扫描量热仪数据处理站专用计算机原程序进行修改的工作，并与通用微机联用，改进了原数据处理站的输出方式，扩展了数据处理功能。