基于主成分回归模型的湖南省就业影响因素分析

针对湖南省就业人数的影响因素问题,首先利用灰关联分析和相关系数法优选出对就业人数影响较大的指标,然后对优选的指标进行主成分分析得出了主成分表达式,最后将就业人数与主成分进行回归得到了就业人数的拟合方程.结果表明,城市化水平、国内生产总值和居民消费水平对湖南省就业人数的影响最大,从而为政府有关部门的决策提供了一定的参考依据.     

车辆高海拔环境起步性能试验研究

对于全域机动车辆而言,高海拔环境起步性能是评价其高原环境适应性和机动性的重要指标。针对多个型号车辆存在的高海拔环境起步困难问题,在系统开展车辆起步过程动力学分析的基础上,从车辆本身所具有的动力和所受外界阻力两个方面对高海拔环境车辆起步性能影响因素进行了深入分析,通过对某军用履带车辆高海拔起步性能的实车试验验证,确定了发动机低速扭矩特性、传动油温、行驶坡度、使用工况是高海拔环境影响车辆起步性能的关键因素,为车辆论证、研制、试验和使用工作的改进和发展提供了依据。     

单分子电导测量技术及其影响因素

Molecular electronics is an important field for the application of nanotechnologies with an ultimate goal of building functional devices using single molecules or molecular arrays to realize the same functionality as macroscopic devices. To attain this goal, reliable techniques for measuring and manipulating electron transfer processes through single molecules are essential. There are various techniques and many environmental factors influencing single-molecule electronic conductance measurements. In this review, we first provide a detailed introduction and classification of the current well-accepted techniques in this field for measuring single-molecule conductance. All available techniques are summarized into two categories: the fixed junction technique and break junction technique. The break junction technique involves repeatedly forming and breaking molecular junctions by mechanically controlling a pair of electrodes moving into and out of contact in the presence of target molecules. Single-molecule conductance can be determined from the conductance plateaus that appear in typical conductance decay traces when molecules bind two electrodes during their separation process. In contrast, the fixed junction technique is to fix the distance between a pair of electrodes and measure the conductance fluctuations when a single molecule binds the two electrodes stochastically. Both techniques comprise different application methods and have been employed preferentially by different groups. Specific features of both techniques and their intrinsic advantages are compared and summarized in Section 4.     

Influencing factors of microscanning performance based on flat optical component

To decrease the performance difference between the actual microscanning thermal imager and the theoretical value, a germanium lens (placed at a certain angle between the infrared focal plane array and infrared lens) dip angle model of flat optical component microscanning is introduced in this letter. The model is the basis for choosing the dip angle of the germanium lens, which is used in the microscanning thermal imager. In addition, the actual dip angle of the germanium lens is chosen according to the model, the infrared lens parameters of the thermal imager, and the germanium lens parameters of manufacture and installation. Only in this manner can the optimal performance of the microscanning thermal imager based on the flat optical component be obtained. Results of the experiments confirm the accuracy of the conclusions above.     

Aerodynamics of indirect thrust measurement by the impulse method

The aerodynamic aspects of indirect thrust measurement by the impulse method have been studied both experimentally and numerically. The underlying basic aerodynamic principle is outlined, the phenomena in subsonic, supersonic and arc-heated jets are explored, and factors affecting the accuracy of the method are studied and discussed. Results show that the impulse method is reliable for indirect thrust measurement if certain basic requirements are met, and a simple guideline for its proper application is given.     

2010年研究生数学建模竞赛A题综述

第七届全国研究生数学建模竞赛A题是生物信息学中的一个急需解决的问题.虽然有关问题的研究已经经历了十多年,但由于问题的复杂性,人们的认识还很局限,基本的结论大多还以定性的为主,定量的探讨正方兴未艾.对参赛队员来讲解决该问题是一个极大的挑战.研究生们在讨论该问题时,大多直接进行分类.然而对于一个小样本的学习问题,显然这样做是行不通的.所以问题的关键是从数学和生物学角度减少用于分类的特征数目.同时,对于获取的基因标签,需要从临床上或生物学角度找到验证.该问题的求解过程引导研究生们从数学建模走向解决实际问题.     

污泥的超声破解实验研究

本文在测量超声破解污泥试验所用反应器声场的基础上,主要研究了复频超声作用下,超声频率和换能器位置对污泥破解效果的影响。在此基础上采用两个同相换能器,以污泥滤液COD、NH₃-N、TP的增量,首次研究了复频超声破解污泥的效果,且详细探讨了影响复频超声破解污泥的影响因素（不同频率组合、不同功率组合、不同时间组合）。实验结果与理论分析符合较好,从而说明超声是一种有效的破解污泥的方法,进而对超声处理污泥的规律进行研究,这将为超声处理污泥提供一定的实验基础。     

激光空间相干合成效果评价方法的研究

根据目标上实际最大光强与理想合成效果下最大光强的比值定义了合成效果因子,用以评价相干合成效果.在此基础上研究了影响相干合成效果的主要因素,并对合成效果因子的传输特性进行了研究.结果表明:阵列紧密程度对合成效果影响不大,在较小的空间占空比下有可能得到较好的合成效果.影响合成效果的主要因素是随机相位差,当随机相位差增大到一定程度时,光束合成其实已经由相干合成过渡到了非相干合成,得不到预期的相干合成效果;随着传输距离的增大,空间占空比对合成效果因子的影响将进一步减小,影响合成效果的主要因素之一是随机相位差.     

《分析化学》征订启事

邮发代号12-6《分析化学》(ISSN 0253-3820,CODEN FHHHDT,CN 22-1125/O6)是中国科学院和中国化学会共同主办的专业性学术期刊,主要报道我国分析化学创新性研究成果,反映国内外分析化学学科前沿和进展。刊物设有特约来稿、研究快报、研究报     

欢迎订阅《Chemical Researchin Chinese Universities》

正《Chemical Research in Chinese Universities》(CRCU,高等学校化学研究,英文版,双月刊)创刊于1984年,是中华人民共和国教育部委托吉林大学主办的英文版化学学科综合性学术刊物,为SCI收录期刊,2012年影响因子0.735。《CRCU》聘请了87位学术造诣精深的国内外知名化学家组成学术阵容强大的编委会,其中中国科学院院士37位。主编为中国科学院院士、高分子化学家周其凤