Meteorological observations on Mount Everest in 2005

Mount Everest,the highest point on the Earth is often referred to as the earth's third pole as such the place is relatively inaccessible and little is known about its meteorology.In April 2005,an automatic weather station was installed at the mountain's North Col(6523 m a.s.l.).According to the observational 10-minute mean and daily records,the meteorological characteristics were analyzed. All the meteorological elements displayed obvious diurnal variations during May 1 to July 22,2005.The monthly variation of daily meteo- rological elements on Mount Everest coincided with that on Dingri,the closest routine meteorological station,with the high correlation co- efficients of 0.928,0.877,0.682,0.755,0.826 and 0.676(n=83,p<0.001)for mean temperature,minimum temperature,max- imum temperature,relative humidity,pressure and wind speed,respectively.Furthermore,the vertical mean gradient of temperature was above 0.6℃/100 m,especially for the daily maximum temperature.Most weather events on Mount Everest prominently appeared on the same day as those on Dingri,especially those from daily mean pressure,temperature and relative humidity with the cross-correlation coeffi- cients of 0.673,0.485 and 0.487(n=83,p<0.001),respectively.Some other weather events on Mount Everest lagged one-day be- hind those on Dingri.Furthermore,forecasting of the weather events on Mount Everest from pressure on Dingri was more reliable than those from the other meteorological elements.The conclusions are much important for research on meteorology and climate changes in the region.     

Scanning for sisnatures of geosraphically restricted selection based on population genomics analysis

Natural selection, as the driving force of human evolution, has direct impact on population differentiation. However, it is still unclear to what extent the genetic differentiation has been caused by natural selection. To explore this question, we performed a genome-wide scan with single nucleotide polymorphism （SNP） data from the International HapMap Project. Single locus FsTanalysis was applied to assess the frequency difference among populations in autosomes. Based on the empirical distribution of FsT, we identified 12669 SNPs correlating to population differentiation and 1853 candidate genes subjected to geographic restricted natural selection. Further interpretation of gene ontogeny revealed 121 categories of biological process with the enrichments of candidate genes. Our results suggest that natural selection may play an important role in human population differentiation. In addition, our analysis provides new clues as well as research methods for our understanding of population differentiation and natural selection.     

Linear and third-order nonlinear optical properties for the heptamethine cyanine chromophore H-aggregates thin film

The thin film of a heptamethine cyanine chromophore HC was prepared by spin-coating technique. Its surface morphology and linear optical property were characterized by atomic force microscopy (AFM) and UV-visible absorption spectroscopy. The results show that HC molecules are arranged in a well-ordered H-aggregate type. The third-order nonlinear optical properties of the spin-coating film were also measured by degenerate four-wave mixing (DFWM) measurement. Enhanced third-order nonlinear susceptibility can be attributed to molecular aggregation effects, and the corresponding mechanism was dealt with by collective electronic oscillator (CEO) approach.     

Density functional theory study on the insertion reaction mechanism of dibromocarbene with formaldehyde

The insertion reaction mechanism of CBr2 with CH3CH2O has been studied by using the B3LYP/6-311G(d) and CCSD(T)/6-311G(d) at single point. The geometries of reactions,transition state and products were completely optimized. All the transition state is verified by the vibrational analysis and the internal re-action coordinate (IRC) calculations. The results show that reaction (1) is the dominant reaction path,which proceeds via two steps: i) two reactants form an intermediate (IM1),which is an exothermal re-action of 8.62 kJ·mol?1 without energy barrier; ii) P1 is obtained via the TS1 and the H-shift,in which the energy barrier is 44.53 kJ·mol?1. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of this reaction in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature ranges from 200 to 1900 K at 1.0 atm,in which the reaction has a bigger spontaneity capability,equi-librium constant (K) and higher rate constant (k).     

田径运动员左心收缩时间间期的分析与评价

采用MCA-3心脏功能综合检测仪,测量田径运动员静态心脏收缩时间间期各指标,分析其特点并与非运动员进行比较,从而对田径运动员的左心功能作出系统的评价。结果发现,田径运动员的LVET、EMT、MSTI、CT及PEP等指标值均比一般人群的指标值高。田径运动员的左心功能呈现机能节省化。     

非接触式霍尔位移传感器的研制及应用

介绍了一种利用霍尔效应实现位移测量的新型传感器，实验研究表明：在3mm的量程范围内精度可以达到0．01mm．应用这种传感器，可以实现钢管、钢棒、钢丝绳等细长构件的直径动态连续测量．     

煤泥浮选最佳粒度的试验研究

把浮选用的煤泥分成三个粒度级，采用均匀设计试验法，确定了在一定工艺条件下的最佳浮选粒度组成。     

《古舟子咏》中信天翁被射杀情节之透析

《古舟子咏》是英国浪漫主义杰出代表,＂湖畔派诗人＂之一塞缪尔·泰勒·柯尔律治（Samuel Taylor Coleridge）的经典诗作。此诗神秘怪诞,寓意丰富。而笔者所关心的是信天翁为何被射杀,及这一简单故事情节在全诗中的作用及与主题的关系。本文将从作者的创作技巧,宗教象征意义和心理学角度三方面来分析。     

对知识型员工管理若干问题的探讨

文章阐述了知识型员工的概念、特点，并提出对知识型员工的管理策略。