激光雷达观测北京大气气溶胶的垂直分布

利用激光雷达对北京2005年4月26—30日大气气溶胶进行了连续观测,对气溶胶光学特性进行了测量和分析,讨论了大气污染物气溶胶和沙尘气溶胶的垂直分布,以及沙尘气溶胶的传输和沉降过程。因此,激光雷达是研究阴霾天气和沙尘天气特征的有效手段。     

自组织型光纤激光器阵列的理论研究

主要对自组织型光纤激光器阵列技术进行了理论研究。重点利用耦合迭代法对自组织型相干光纤激光器阵列进行了分析,并给出了电场和增益系数的耦合迭代方程。对进一步对自组织型光纤激光器进行数学建模和理论分析提供了理论基础。     

交换局部环和半局部环

本文是在W·V·Vasconcelos研究的基础上,将Auslander,Vasconcelos等人的一些结果进行推广,对局部环和半局部环上的模及其同调性质作了进一步刻划。Auslander-Buchsbaum-Nagata用同调代数的方法证明了用其它方法还无法证明的著名定理:每个正则局部环是唯一分解整环。本文采用同调代数与环论相结合方法证得定理:若A是一个不可分的凝聚半局部环,且每个主理想有有限投射维数,则A是最大公因子整环。从某种意义上讲此定理推广了Auslander-Buchsbaum-Nagata定理的结果。     

Influence of coherent structures in the gas-particle circular cylinder wake flow

INTRODUCTION Turbulent gas-particle flows are frequently found in natural phenomena and industrial processes.Cases of cylinders in cross flows with particles occur in heat exchange equipment,including the convective zone of a fluidized-bed combustor,and in the primary superheaters,reheaters,and economizers of coal-fired boilers.Coherent structures often occur in the above-mentioned gas-particle flow,and have great effect on such different systems,while some features of tur-bulent multiphas…     

激光雷达遥感进展

本文综述激光雷达在遥感方面的发展,分别介绍各种激光雷达的基本原理,并指出今后激光雷达的发展方向.     

Large eddy simulation of the gas-particle turbulent wake flow

To find out the detailed characteristics of the coherent structures and associated particle dispersion in free shear flow, large eddy simulation method was adopted to investigate a two-dimensional particle-laden wake flow. The well-known Sub-grid Scale mode introduced by Smagorinsky was employed to simulate the gas flow field and Lagrangian approach was used to trace the particles. The results showed that the typical large-scale vortex structures exhibit a stable counter rotating arrangement of opposite sign, and alternately form from the near wall region, shed and move towards the downstream positions of the wake with the development of the flow. For particle dispersion, the Stokes number of particles is a key parameter. At the Stokes numbers of 1.4 and 3.8 the particles concentrate highly in the outer boundary regions. While the particles congregate densely in the vortex core regions at the Stokes number of 0.15, and the particles at Stokes number of 15 assemble in the vortex braid regions and the rib regions between the adjoining vortex structures.     

Teachers’ beliefs systems about improving transfer of algebraic skills from mathematics into physics in senior pre-university education

Senior pre-university education (SPE) students experience difficulties applying mathematics to physics. This paper reports the outcome of an online explorative quantitative study of teachers' belief systems about improving transfer of algebraic skills from mathematics into physics, conducted among 503 mathematics and physics teachers working in SPE. We used a questionnaire with 16 beliefs about improving transfer, and asked teachers to select a top 5 and distribute 50 points among them. We used agglomerative hierarchical clustering to cluster qualified SPE teachers with more than 10 years of teaching experience. We found 3 large clusters, each containing naïve and desirable beliefs about transfer. These clusters turned out to be rather coherent sets of beliefs. Hence, these clusters can be interpreted as belief systems, to a certain extent justifying Ernest's [(1991). The philosophy of mathematics education. London: Falmer.] idea to cluster teachers based on their belief systems. We found relations between our groups and those of Ernest. Since naïve beliefs turn out to be weak in each cluster, science teacher educators can help science teachers to change their harmful naïve beliefs, into desirable transfer enhancing beliefs. Furthermore, we discuss some implications of our results for science teacher educators, curricula, teachers and textbooks.     

Large eddy simulation of the gas-particle turbulent wake flow

INTRODUCTIONPlanewakeflowisonetypeoffreeshearflowandexistswidelyinnatureandmanyengi neeringsystems.Tounderstandthekineticchar acterofthelarge scalecoherentvortexstructuresandparticledispersioninplanewakeflowishelpfulforimprovingmanyprocessesinenergyengineering,chemicalengineeringandmaterialengineering .LargeeddysimulationinvolvesbothdirectsimulationandReynolds averagedapproaches.MethodshavebeendevelopedinrecentyearstosolvetheproblemofinstantaneousgasflowfieldandtosimulatehighReynoldsnumb…     

浅析继续教育与经济发展的辩证关系

继续教育与经济发展的关系密切,相互影响。开展继续教育能够促进教育资源的有效利用,也可为经济发展提供高素质人才。同时,经济发展对继续教育的形式和内容产生重要影响。正确认识和处理继续教育与经济发展的关系,有利于更好的开展继续教育工作,提高经济发展效率,充分发挥二者在我国社会主义建设中的作用。     

光自差CO2相干激光雷达光学头设计与测试

对光自差阵列探测CO2激光相干雷达进行了研究，通过对大量红外光学系统的分析，提出了一种适用于光自差阵列探测激光相干成像的光学头系统，并对该光学头系统进行了设计和实验性能测试，该光学头系统可实现光束的一维扩展，其纵横向扩展比为1：32。