甘肃敦煌南湖自然保护区生物多样性及保护对策

敦煌南湖自然保护区面积11.06 km^2,以荒漠之中的湿地和候鸟为主要保护对象.相对西部其它荒漠地区而言,保护区内生物多样性丰富,植物群丛多样,重点保护鸟类众多.已查明物种283个,种子植物141种,动物142种,植被群落类型40个.针对保护区生物多样性面临的威胁,提出了生物多样性保护和可持续利用对策.     

Direct evidence of phosphorus outbreak release from sediment to overlying water in a large shallow lake caused by strong wind wave disturbance

Concentration variations of suspended solids (SS), total phosphorus (TP), dissolved total phosphorus (DTP), dissolved reactive phosphorus (SRP), and algae available phosphorus (AAP) in overlying water were observed during the coldest week in a year in Lake Taihu, a large shallow lake in China. Water samples at different water depths were collected with wind speeds of 8, 12, 0 and 0 m/s on 23, 24, 26 and 30 January 2004, respectively. On 23 January 2004, SS concentration increased to 258 mg/L with a wind speed of 8 m/s lasting for 1 h. SS concentration kept increasing and reached to 507 mg/L when the strong wind lasted for 24 h and the peak value of wind-speed reached to 12 m/s on 24 January 2004. On 26 January 2004, SS concentrution decreased to 51 mg/L with the wind speed smaller than 2 m/s lasting for about half a day. Then after five continuous waveless days, SS concentration decreased to 21 mg/L on 30 January 2004. The observed results confirmed that sediments in Lake Taihu would be intensively suspended if the surface wind speed is greater than 8 m/s, and the magnitude of SS would increase with increasing wind-speed. Coupled with the intensive sediment suspending, concentrations of TP, DTP and SRP on 23 January were 0.210, 0.048 and 0.035 mg/L, respectively. And they were 0.299, 0.054 and 0.026 mg/L on 24 January, which were significantly higher than those on 26 and 30 January. SRP concentration on 23 January was twice as high as that observed on 30 January. It indicates that the strong wind may result in an outbreak release of phosphorus. Moreover, AAP contents in suspended solids were 132, 97 and 226 mg/kg on 23, 24 and 26 January, respectively. Therefore, it could be estimated that this strong wind process resulted in 987 t of TP, 80 t of SRP and 167 t of AAP releasing from sediments into overlying water. Since such strong wind process is frequent in the area of Lake Taihu, dynamical release driven by wind-induced wave disturbance may be the main mode for internal release of phosphorus. It must have important effects on the nutrient supply during Microcystis bloom in Lake Taihu.     

关于小波空间的框架

无论是信号处理，还是图像处理，首先要把模拟信号转换成数字信号，如何转换就涉及到采样问题，而框架理论是研究非均匀采样问题的一个重要工具．文章讨论若{2j/2ψ（2^jx-λn），n∈Z}是Wj的框架，对与另一采样集{an，n∈Z}满足什么样的条件，使得{2^j/2ψ（2^jx-an）,n∈Z}也是Wj的框架。     

三点法圆度误差分离及演化形式与精度分析

论述了圆度误差分离的三点法及演化形式-二点法和四点法的基本原理，通过分析它们各自的特点和测量精度指出权函数的取值是影响测量精度的关键因素，应通过合理选择测量系统参数以避免谐波抑制的发生，而且应针对具体情况选择适当的圆度误差分离方法。     

有限带宽条件下VOD服务器的设计

分析了ＶＯＤ系统的构成及其实时服务过程，基于Ｍｋ／Ｍ／１的排队过程计算了系统参数对系统性能的影响．给出了设计实时多媒体服务器最大同时访问用户数和缓冲器大小的计算式，并提出了改进服务器性能的ＴＩＰＭＳ方法．将该方法与ＱＰＭＳ的方法进行比较，表明ＴＩＰＭＳ有效地改善了服务器的性能     

Comparative Analysis and Fuzzy Selection of Information System Development Approach

ＣｏｍｐａｒａｔｉｖｅＡｎａｌｙｓｉｓａｎｄＦｕｚｚｙＳｅｌｅｃｔｉｏｎｏｆＩｎｆｏｒｍａｔｉｏｎＳｙｓｔｅｍＤｅｖｅｌｏｐｍｅｎｔＡｐｐｒｏａｃｈ⒇ＣＨＥＮＸｉａｏｈｏｎｇ＊ＬＩＵＭａｉ＊ＹＡＳＵＨＩＫＯＴａｋａｈａｒａ＊＊＊ＣｏｌｅｇｅｏｆＢｕｓ...     

测定逐级络合物稳定常数的等色点——平衡移动法

本文将平衡移动法应用于逐级络合物稳定常数的测定,对相互交错严重的逐级络合反应,利用计算机自动寻找严格的实验条件,使系列溶液吸收光谱形成等色点,以判断反应进程,从而将复杂的逐级平衡分解.方法简便可靠,实验条件严谨,用以测定经典的铁-磺基水杨酸体系,取得了满意的结果.     

有限温度下介观LC电路瞬时本征态的量子涨落

通过将热场动力学推广到含时体系，研究了有限温度下介观含时LC电路中的量子涨落．虽然温度的升高会使量子涨落增加，但电容和电感等物理量的时间变化却能使涨落减小．电源的存在会对电荷和磁通量的平均值有贡献，但不会影响量子涨落．当电路中有电源时，电荷和磁通量的平均值会依赖于温度；而当电路中没有电源时，各平均值为零，自然与温度无关．     

基于B.M.E.P的活塞发动机涨圈磨合分析简

本文简要介绍了航空活塞发动机渗氮汽缸的特点,分析了汽缸磨合时在B.M.E.P作用下汽缸壁和涨圈的工作状况,并根据二者的工况特点阐明了发动机的磨合机理及影响磨合的其它因素,最后提出相应建议.     

气体绝缘封闭开关设备检修机器人研究进展

气体绝缘封闭开关设备(Gas-Insulated metal-enclosed Switchgear,GIS)事故及重大缺陷频发,严重危害到电网的安全稳定运行。与传统检修方法相比,采用机器人技术实现GIS腔体内部巡视检查、故障点识别定位,具有显著的优势和重要的意义。作为机器人技术的一个新兴的应用领域,国内外对GIS腔体机器人的研究尚处在初级阶段。本文调研了国内外在管道机器人的研究和应用现状及GIS腔体机器人的初步研究,分析了GIS腔体机器人的关键技术难点,展示了项目组的最新研究进展,并给出下一阶段研究方向的建议。