Difference in direct charge-parity violation between charged and neutral B meson decays

Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter-dominated. One of the prerequisites for understanding this elimination of antimatter is the nonconservation of charge-parity (CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson (K(0)) and B meson (B(0)) systems: CP violation involving the mixing between K(0) and its antiparticle (and likewise for B(0) and ), and direct CP violation in the decay of each meson. The observed effects for both types of CP violation are substantially larger for the B(0) meson system. However, they are still consistent with the standard model of particle physics, which has a unique source of CP violation that is known to be too small to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B(+/-)-->K(+/-)pi(0) decay is different from that in the neutral B(0) counterpart. The direct CP-violating decay rate asymmetry, (that is, the difference between the number of observed B(-)-->K(-)pi(0) event versus B(+)-->K(+) pi(0) events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement. However, the asymmetry for versus B(0)-->K(+)pi(-) is at the -10% level. Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation-which would help to explain the dominance of matter in the Universe.     

Elemental composition in surface snow from the ultra-high elevation area of Mt. Qomolangma （Everest）

A total of 14 surface snow （0-10 cm） samples were collected along the climbing route （6500-8844 m a.s.h） on the northern slope of Mt. Qomolangma in May, 2005. Analysis of elemental concentrations in these samples showed that there are no clear trends for element variations with elevation due to redistribution of surface snow by strong winds during spring. In addition, local crustal aerosol inputs also have an influence on elemental composition of surface snow. Comparison between elemental concentration datasets of 2005 and 1997 indicated that data from 2005 were of higher quality. Elemental concentrations （especially for heavy metals） at Mt. Qomolangma are comparable with polar sites, and far lower than large cities. This indicates that anthropogenic activities and heavy metal pollution have little effect on the Mt. Qomolangma atmospheric environment, which can be representative of the background atmospheric environment.     

THz spectra of five borates crystals

Terahertz spectral responses have been studied for five borate crystals Nas[B2P3O13] （NBP）, Zn3BPO （ZBP）, SrB407 （SBO）, Na3LagO3（BO 3）8 （NLBO） and PbB407 （PBO）. It is found that the samples had good transmission in 0.25--1.5 THz region. Both SBO and NLBO have an absorption coefficient less than 10 cm^-1. Among them, SBO has not only the smallest absorption coefficient but also a very flat dispersion in the frequency region under investigation. Distinct resonance absorption peaks are observed for ZBP at v1 = 1.4 THz, v2 = 2.0 THz and SBO at v = 2.4 THz. In the spectrum of PBO, two abnormal dispersions appear in the frequency regions 1.44--1.74 and 2.2--2.5 THz. The absorption coefficients and refraction indices of the five crystals are extracted from the THz time-domain （THz-TDS） spectra in 0.25--2.5 THz region. The properties and origins of the spectral responses are addressed.     

Exploration of energy conservation MAC protocol of WSNs for ubiquitous environment

According to analyze the facade phenomenon of wire-less sensor networks（WSNs）,this paper proposes a feasible method to state clearly and improve the power control efficiency of wire-less sensor networks（WSNs）. One of the crucial problems for WSNs is the design of medium access control （MAC） protocol. Our method want to adjust the activities of the MAC protocols control to achieve the enery conservation when the wireless communication module of sensor nodes is running, which is the major consumer of energy consumed by sensors energy. The energy efficiency of MAC protocol makes a strong impact on the network performance. To some extent,our research work describes and analyze the sources of energy consumption in MAC layer and simultaneously present an optimal method for the design of MAC protocol. Then we discusses some factors impacting on the performance of MAC protocol and metrics of performance evaluation. Eventually, the coming research direction is summarized.     

现代大学“以人为本”教育理念探析

在我国历史长河中。“以人为本”有着深远的历史渊源。文章通过对中西方“以人为本”思想的历史考察,追溯了现代大学“以人为本”教育理念的缘起,筒述了现代大学“以人为本”教育理念的概念及基本观点。     

目的论视阈下的中文报刊新词英译

针对传统的翻译标准“忠实”、等值“无法解释中文报刊新词必要的翻译现象,以德国功能学派翻译理论家H.J．弗米尔（H.J．Vermeer）提出的“目的论”为切入点,探讨了目的论在中文报刊翻译中的应用,目的论的提出拓宽了翻译理论研究的领域。     

基于总体性思维的企业技术创新体系分析

从纵向视角和横向视角分析了企业技术创新体系的组成性,并将企业技术创新主体划分为员工个体、部门和公司(总部)等三个组织层次。接着分析了企业技术创新体系构建与运作过程中,单纯运用整体性思维的局限性,明确提出了切实运用总体性思维以最大化企业技术创新体系的总体功能。最后指出,为培育和提升企业技术创新能力,企业必须从员工个体、部门和企业(总部)三个层次上,确立企业技术创新主体的层次性体系。     

GPS系统在现代电子对抗中的应用探讨

介绍了GPS系统的组成、原理,分析了GPS系统在电子对抗技术中的策略建模,并从影响GPS系统的干扰因素入手讨论了GPS系统干扰技术及抗干扰技术。     

不同化学粗化方法对ABS塑料化学镀镍的影响

采用CrO_3粗化体系、MnO_2-H_3PO_4-H_2SO_4粗化体系和KMnO_4粗化体系三种不同的化学粗化法对ABS塑料进行粗化处理,然后用盐基胶体钯进行活化,并在碱性条件下进行化学镀镍。用SEM对粗化后基材的表面形貌进行表征,采用重量法、划格法对镀速以及镀层结合力进行测试。结果表明,采用KMnO_4体系对ABS塑料进行粗化处理后的结合力与镀覆情况接近采用传统工艺—CrO_3粗化体系得到镀件。