聚联苯醚二甲酰十二碳二胺的热降解过程与机理

利用热重法研究了半芳香尼龙聚联苯醚二甲酰十二碳二胺(PA12-O)在N2气氛中以不同速率β升温时的热降解过程及热降解动力学.结果表明,PA12-O的热降解是一步反应,随着β的增大,降解温度呈指数关系升高.其起始平衡降解温度为439.4℃,终止时的平衡降解温度为468.33℃,最大降解速率时的平衡降解温度为459.17℃.为确定PA12-O的热降解机理,比较了用Kissinger、 Flynn-Wall-Ozawa和 Coats-Redfern方法求得的PA12-O的热降解表观活化能,证明PA12-O的热降解机理为减速类型.     

北京市工业废气排放的环境库兹涅茨特征及因素分析

以工业总产值代表工业经济发展状态指标，工业废气排放总量代表工业大气污染指标，采用多种函数模型对北京市工业废气排放的环境库兹涅茨曲线作了函数优选拟合研究，揭示了近10年来北京市工业发展的环境经济动态轨迹，并且进一步运用因素分析法对工业废气污染态势从经济总量、技术进步、协同交叉作用三方面作了分析，研究表明工业环境经济可持续发展关键在于经济总量增长与单位经济产出的环境负荷二者之间的协调．     

溶剂效应对中氮茚荧光性质的影响

合成了一系列中氮茚化合物，比较了它们在不同有机溶剂中紫外光谱和荧光光谱的变化情况，探索了化合物的微观结构与其光学性能之间的某些关系，结果表明溶剂极性对该类化合物吸收光谱的影响不明显，但对化合物的Stokes位移、荧光强度以及荧光量子效率的影响都较大，中氮茚化合物分子的荧光特性首先取决于它自身的分子结构，特别是各种能增强系间穿越过程的取代基的存在，而外界因素，如介质，温度、压力、浓度、酸度等对试剂荧光特性也有很大影响．     

个性化网络教学模型及实现策略研究

首先分析网络教学的理论模型，结合代理技术与分布对象计算技术，给出一个基于建构主义学习理论的个性化网络教学模型，论述个性化网络教学实现策略及实现参考模型，该模型基于知识应用模式及其建构的认知结构以及在此基础上的互动教学，支持分布式个性化网络教学．最后给出相应的样例及其分析．     

有限规模下网络话音复用带宽的近似评估

通过对网络话音业务的近似分析和仿真，建立了相对简单的复用带宽分配机制．首先对规模较小、性能参数比较确定的接入网进行建模和具体分析，然后利用网络仿真器对所建模型丢失率随带宽变化的特性等进行了仿真，对缓冲区与时延等影响网络话音复用带宽的重要因素进行了讨论．仿真结果表明，在网络为有限规模时，本文的结论对于确定区分服务中应当分配给IP电话业务的网络带宽有实用意义．     

大型组播网络中的Anycast RP机制

鉴于在运行PIM SM的大型组播网络中 ,RP是一个单点故障点 ,在分析了MSDP协议原理之后 ,给出了任意播解决方案 ,以实现负载均衡和容错     

Lightning activity on the central Tibetan Plateau and its response to convective available potential energy

Lightning flash activities on the central Tibetan Plateau have been studied by using the satellite-based Lightning Imaging Sensor(LIS)database from January 1998 to July 2002.The lightning activity shows a clear diurnal variation on the central Plateau.The peak lightning activity appears at about 17:00 which is 3 h earlier than that in Jingxhou,Hubei in the same latitude belt nearby,indicating that the lightning activity is a sensitive indicator of solar heating on the Plateau.The lightning discharge is weaker on the Plateau than Jingzhou.Hubei and other low-altitude continental regions because of the lower convective available potential energy(CAPE)on the Plateau.The CAPE on the Plateau is 12 times lower than that in Jingzhou,Hubei,and 20 times lower than that in the sea-level region,such as Guangzhou and Florida.However,the sensitivity of lightning activity to CAPE changes on the Plateau is up to 30 times more sensitive than other prominent low-altitude regions.     

C－isotope composition and significance of the Sinian on the Tarim plate

102 samples of limestones,mudrocks shales and tillites from the Sinian in Kuluketage have been analyzed ,Four formations in the Sinian belong to glacial deposits in which the differences in δ^13C are distinct (-14.7‰- 4.2‰),Distinctly negative δ^13C excursions for three times support the viwe of three glacial deposits in this area suggested by previous authors,except for the durations of them ,δ^13C values are generally positive in the Beiyixi Formation of lower part of the Lower Sinian ,representing probably the rock records of a continental rift related to break-up of the Rodinian supercontinent,There are three times of distinct excursions of δ^13C curve in all strata,The first one is from positive values at the bottom to about -5‰ at the top of the Beiyixi Formation ,The second one,from 0‰-3‰ in the Arletonggou Formation of upper part of the Lower Sinian to -3.4‰---14.4‰ in the Teruiaiken Formation.The third one,from positive values in the Zhamoketi Formation of lower part of the Upper Sinian to negative values in glacial varves at the top of the Hankeerqiaoke Formation.     

A new Euprox from the Late Miocene of Yuanmou,Yunnan Province,China,with interpretation of its paleoenvironment

The Yuanmou Basin of Yunnan Province is a hotspot for the research of early homind evolution and its environmental background.During the implementation of the Program“Research of the Origin and Evolution of Early Man and Its Environmental Baqckground” from 1998 to 2001,a huge quantity of hominoid and mammal fossils were collected.The present report systematically describes an Euprox robustus sp.nov.identified during the recent laboratory work on the collected material.Euprox is a group of earliest cervids with true antlers.The new species is the third one of the genus discovered in China.Judged by its morphologic characteristics,the new species feed on juicy and tender leaves of dicotyledon.It implies that the vegetation of its epoch in the Yuanmou Basin is a kind of southern subtropical evergreen forest and the climate is humid and temperate with evident seasonality.The latter is mostly influenced by the monsoon and secondly by the latitude.     

Inorganic chemical composition and source signature of PM2.5 in Beijing during ACE-Asia period

Aerosol samples for PM2.5 were collected in Beijing for 38 consecutive days from March to April 2001 using an IMPROVE Sampler. Concentrations of 20 elements in PM2.5 were determined using a PIXE method. Results show that the average mineral dust concentration of PM2.5 was 14.6 Ilg/m3 during the observation period. On the sand-dust event days of March 21 and April 10, dust PM2.5 mass concentrations were 62.4 and 54.1 μg/m^3, respectively.These demonstrate that fine particle pollution by dust event in Beijing was very severe. The enrichment factors of S and Cu reached minimums on the dusty days and were high on the non-dusty days. It is considered that enrichment factors of elements in PM2.5, which are associated with human activities, can probably provide an effective method to distinguish local sources from external sources of dust. Factor analysis on the chemical composition in PM2.5 shows that sources of crustal matters, anthropogenic emission, and oil combustion contributed to PM2.5 levels in air in the springtime of 2001 in Beijing.