建国以来塔里木河流域生态环境研究进展与展望

建国以来，塔里木河流域生态环境研究的内容不断深入，研究的技术和手段也不断地改进。本对这时期塔里木河流域生态环境的研究进展、研究方法和技术作了综述。在此基础上总结了历来的研究经验和存在的问题，并对塔里木河流域生态环境的发展趋势做了展望。     

壮族学习普通话语音瓶颈论——塞擦音、送气音存在的问题及解决途径

探讨壮族群众说普通话时 ,常将塞擦音读成擦音 ,送气音读成不送气音等这两个问题的解决途径     

织物紧度及织物组织与喷水织机效率的分析

结合生产实践，定量或定性地讨论了织物紧度及织物组织与织机生产效率的关系，可供产品设计时预测织机效率，以求开发既符合织物风格要求，又有良好织造性能的产品。     

电偶极辐射的微机模拟

本文介绍了电偶极辐射从理论到微机模拟的实现过程．我们开发的软件作为演示实验已经取得了良好的效果     

一类热传导分布参数系统的边界控制

利用微分方程对称以及其与无穷小生成元的关系,针对几种不同控制目标要求的一类热传导分布参数系统,研究了边界控制问题,设计出不同的边界控制律,分别实现了定点等速升温控制、定点稳态温度控制、边界稳态温度控制。对不同控制目标设计的控制律均进行了仿真验证,结果表明了控制条件的有效性。     

Mg-Zr处理对FH40级船板钢铸态夹杂物特征的影响

采用定量金相及SEM-EDS手段对Mg,Zr及Mg-Zr处理FH40级船板铸钢中夹杂物粒径分布、平均粒径、总数量、总面积及成分、形貌等特征进行系统研究.结果表明,Mg,Zr及Mg-Zr处理后铸锭夹杂物平均粒径下降,夹杂物总数量增加.Mg的质量分数为0024%时,夹杂物中MgO平均质量分数为1257%,变质不充分;Mg的质量分数增加至0072%后,夹杂物中MgO平均质量分数为3558%,实现了氧化铝向MgO·Al2O3的充分变质,且夹杂物粒径明显减小.003%Zr处理后,铸锭夹杂物以Al2O3+MnS,Al-Zr-O+MnS为主;低Mg+高Zr,高Mg+低Zr,高Mg+高Zr处理炉次试验钢铸锭中均发现了含Zr夹杂物,其中高Mg+高Zr炉次形成了ZrO2夹杂,该类夹杂物被MgO·Al2O3包裹,团聚现象明显.     

一种基于关键帧的视频保护方案的设计与实现

视频作为目前最广泛的流媒体之一,其版权保护逐渐得到人们的重视.为了对视频文件进行保护,从加密算法、索引序列和关键帧加密三个角度,设计了一套基于关键帧加密的视频保护方案.首先利用AES算法对解码前视频流的关键帧进行加密;然后利用MD5对I帧及其随后的连串的B、P帧产生索引序列,保证数据的安全性与完整性.方案避免了转码过程出现的失真与大量时耗,同时利用了FFmpeg良好的视频编解码处理能力,克服了单纯靠加密算法保证安全的单一性;最后在理论与实验中分析了其安全性、实用性和高效性.     

华南季节干旱及连旱特征分析

 利用1951-2006年实测降水量资料,通过统计方法分析了华南各季节降水量的时空变化及季节干旱特征。结果发现,各季降水量总体上在华南区域空间尺度上有显著的同号变化关系。华南夏季降水量的距平幅度增大,并有增多的长期趋势;秋季降水量则有距平幅度减弱的长期趋势;冬春季降水量的逐年变化存在显著的同相关系。华南秋季发生干旱的频数较其它季节高;春－夏连旱频数较其它季节连旱事件频数要低。     

Molecular dynamics simulation of the deposition process of hydrogenated diamond-like carbon （DLC） films

The deposition process of hydrogenated diamond-like carbon （DLC） film greatly affects its frictional properties. In this study, CH3 radicals are selected as source species to deposit hydrogenated DLC films for molecular dynamics simulation. The growth and structural properties of hydrogenated DLC films are investigated and elucidated in detail. By comparison and statistical analysis, the authors find that the ratio of carbon to hydrogen in the films generally shows a monotonously increasing trend with the increase of impact energy. Carbon atoms are more reactive during deposition and more liable to bond with substrate atoms than hydrogen atoms. In addition, there exists a peak value of the number of hydrogen atoms deposited in hydrogenated DLC films. The trends of the variation are opposite on the two sides of this peak point, and it becomes stable when impact energy is greater than 80 eV. The average relative density also indicates a rising trend along with the increment of impact energy, while it does not reach the saturation value until impact energy comes to 50 eV. The hydrogen content in source species is a key factor to determine the hydrogen content in hydrogenated DLC films. When the hydrogen content in source species is high, the hydrogen content in hydrogenated DLC films is accordingly high.     

Synthesis of a novel triple-site diphosphinoamine （PNP） ligand and its applications in ethylene tetramerization

A novel triple-site diphosphinoamine （PNP） ligand was synthesized and characterized. In combination with Cr（Ⅲ） and methylaluminoxane （MAO）, it generated active catalytic systems for ethylene tetramerization toward 1-octene with high catalytic activity and long lifetime. The effects of reaction temperature, molar ratio of AI/Cr and molar ratio of ligand/Cr on catalytic activity and selectivity to 1-octene were studied with reaction kinetics of the catalytic system for ethylene tetramerization described. At the AI/Cr molar ratio of 100, the catalytic activity is up to 2.29×10^6 g· mol^-1 （Cr）· h^-1 and the selectivity to 1-octene is 49.65 wt%.