基于双稳阱内随机共振的OFDM信号检测方法研究

为了解决OFDM(orthogonal frequency division multiplexing)传输系统中接收端对微弱OFDM信号的检测问题,本文将双稳阱内随机共振系统与OFDM信号增强和解调过程相结合,推导了多载波信号激励下双稳阱内随机共振系统从零状态变化到势阱状态所需时间的解析表达式,分析了暂态响应导致的多载波信号在一个符号内的能量损失问题;推导了系统稳态输出方程,分析了稳态过程对子载波已调信号叠加直流偏置分量的问题;探讨了在不同系统参数和噪声强度下阱内随机共振对OFDM信号解调性能的影响。仿真结果表明：该方法可有效实现信号与噪声阱内协同作用,提高OFDM信号的检测性能。     

Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity,depth gradient and annual dynamics

Diversity, depth distribution and seasonal activity of isopods and myriapods were studied using subterranean traps buried in a forested limestone scree slope in the ?ierna Hora Mts, Western Carpathians, Slovakia, throughout the depth gradient from 5 to 95 cm. A total of five isopod, 13 diplopod and 11 chilopod species were identified. Most edaphic species strongly preferred the uppermost organic soil layers. Among the species captured, some represented rare stenoecous Carpathian endemics, namely the isopod Trichoniscus carpaticus, and diplopods Julus curvicornis and Leptoiulus mariae. Others were subterranean forms, partly adapted to hypogean conditions: the isopod Mesoniscus graniger, and diplopods Mecogonopodium carpathicum and Trachysphaera costata. The annual activity in the vast majority of the species ceased completely in winter, and was gradually relaunched in spring. In evaluating the age structure of two predominant diplopods Polydesmus denticulatus and Mecogonopodium carpathicum, both widespread across the depth gradient, a vertical segregation of early post-embryonic stages was found. While P. denticulatus tended to undergo the early stages of development in the soil-filled topmost levels, the early juvenile stage of M. carpathicum was distributed deep in the scree slope profile.     

Scientists and their cultural heritage: Knowledge,politics and ambivalent relationships

For many years, scientific heritage has received attention from multiple actors from different spheres of activity—archives, museums, scientific institutions. Beyond the heterogeneity revealed when examining the place of scientific heritage in different places, an authentic patrimonial configuration emerges and takes the form of a nebula of claims and of accomplishments that result, in some cases, in institutional and political recognition at the national level, in various country all around the world. At the international level, the creation of the international committee dedicated to University Museums and Collections (UMAC) within the International Council of Museums (ICOM) certainly testified from this raising interest in academic heritage and the existence of a specific community concern with it.This article presents numerous initiatives for the preservation of scientific heritage in France, with the goal of analysing the relationship scientists have with their heritage. We argue that scientific communities have a special relationship with heritage, which is characterized by a number of ambiguities. We show that such ambivalences allow analysis of identity, discipline, professional, and social issues operative in defining heritage and being redefined by heritage. To explore these dimensions, we have chosen to present three different case studies. The first traces the institutional uses of heritage by a scientific institution, the Commissariat à l’énergie atomique (CEA), through the transformation of the first French atomic reactor (ZOE) into a museum. The second example describes the initiatives of French astronomers from the mid-1990s to construct a national programme for the protection of astronomy heritage. Lastly, we recount the case of universities, with the example of the Université de Strasbourg.     

不同放牧强度下天然沙质草场植物群落分异特征及沙漠化发生机理试验研究

本文通过在科尔沁沙地沙质天然草场进行连续牧压梯度试验，主要得出如下结论：随着放牧强度的增加，植被盖度，地下生物量迅速下降，连续强度牧压下沙漠化在短期内（３～７个月）强烈发展；随着牧压的增加，地下生物量与地上生物量的比值呈上升趋势，土壤含水量也上升；放牧造成的沙漠化在初期阶段相对容易治理。     

短正合列的弱可裂

把短正合列的可裂推广到短正合列的弱可裂，并对弱可裂进行了等价刻画，最后还运用左弱可列证明了平坦模的一个充要条件。     

粒子物理中几种可能应用的新数学方法和拓扑模型

在粒子物理中探讨了四元数、符号动力学等新的数学方法,几种可能应用于振荡的数学方法,及与时间有关的粒子理论;讨论了非线性理论和相应的定性分析理论的结果;研究了粒子的拓扑模型和分形模型;最后提出弱相互作用可能相应于Lobachevsky几何.     

从可持续设计到绿色生态住宅

通过对可持续发展观点的起源，概念，特点的分析，结合我国住宅产业目前的实际情况，阐述了绿色生态住宅小区的基本要求与特点。     

大学生参加社会实践的意义、现状及发展态势

社会实践，是指人类能动地改造自然和社会的全部活动。大学生社会实践是指大学生走向社会，深入基层，为社会服务，直接感受社会生活，进行以社会理想和职业理想教育、劳动技能训练、科学素质培养为主要内容的课外教育活动。当代大学生社会实践的缘起有理论和现实两大依据。改革开放以后，我国大学生社会实践在活动内容、组织形式、制度建设等方面取得了突出成绩，同时也面临一些突出问题。我国大学生社会实践的发展趋势主要体现在四个方面，即活动的社会化、内容的专业化、制度的规范化、组织的科学化。     

地方性本科院校大学生就业情况分析与对策

针对当前就业形势,分析了大学生就业的特点,对当前的就业趋势进行了预测与分析,探索了大学生就业问题的解决对策。