超高精度空间站共视时间比对新方法

随着科学技术的进步和发展,许多基础前沿领域要求时间比对的精度为几十皮秒甚至更高.空间站上的原子钟系统比地面钟性能更优,但传统的共视时间比对方法应用于空间站共视存在一定的局限性.本文基于广义相对论分析了精度为几十皮秒的空间站共视时间比对原理,考虑了所有的皮秒级以上的时延项;结合空间站共视时间比对原理,仿真分析了空间站对于中国几大主要地理城市的可见性,分析结果表明部分地区存在共视时间比对的工作盲区.结合理论和仿真研究了空间站轨道误差对传统共视时间比对方法的影响,研究结果表明传统共视时间比对方法不能有效地抵消轨道误差,其对共视时间比对的影响在几百皮秒量级.提出了空间站分时共视时间比对新方法,介绍了该方法的主要原理和优势.通过仿真实验验证了新方法的有效性,能够实现几十皮秒精度的两地面站远距离共视时间比对,同时解决了传统共视方法的工作盲区问题.     

清江大龙潭水利枢纽防渗帷幕设计及效果监测分析

大龙潭水电站坝址位于碳酸盐岩地区,岩溶发育受岩性和构造控制：在奥陶系南津关组第一段(O1n1)页岩夹灰岩、第二段第一层(O1n2-1)泥质条带灰岩及寒武系第四段第二层硅质条带灰岩(∈4-23m)中岩溶不发育,其他地层的灰岩中岩溶发育; 岩溶发育方向主要沿岩层层面和顺河向的断层发育,形成岩溶通道。因此水库渗漏主要沿岩溶发育的断层产生,防渗帷幕设计以奥陶系底部188m页岩为防渗依托,并重点加大断层部位的工程量。后期地下水长期观测分析表明,帷幕防渗效果良好,不存在大的库水渗漏,仅在局部断层构造发育部位渗漏量略大。大龙潭水电站防渗帷幕工程成功的范例为碳酸盐岩地区其他工程的防渗优化设计提供了很好的借鉴意义。     

南线A污水泵站水力模型试验及其优化

上海市污水治理二期工程是我国最大的污水治理工程,此项工程的目的是为了减轻黄浦江上游水质污染.南线A号污水泵站是上海市污水治理二期工程之一.本文通过水力模型试验,发现原设计泵站流态较为恶劣、水泵效率下降和泥沙沉积严重.在原设计基础上以增加八字形导流墩、压水板、挡水板作为改进措施进行多种工况试验,均可获得较好的流态及流速分布,水泵效率也有明显的提高.     

水电工程机电设备成套项目供应商灰靶优选

为进行水电工程机电设备成套项目供应商选择,综合运用灰色系统理论,提出供应商灰靶分析与优选方法.首先,结合机电设备成套项目特点,建立包括产品水平、企业条件、合作潜能、服务保障等4个一级指标和18个二级指标的水电工程机电设备成套项目供应商优选指标体系;然后,采用G1法确定指标权重,构建供应商灰靶优选模型,计算比较各序列靶心距;最后结合实例,为越南Song Bung 5水电站机电设备成套项目总承包商选择理想供应商.结果表明:通过建立供应商灰靶优选模型,实现各潜在供应商间的量化分析,有利于降低工程项目管理难度,最大限度发挥机电设备成套项目管理优势。     

一种提高差分GPS基准站定位精度的新方法

在差分GPS系统的应用中，基准站的精确定位是一个重要问题，本文首先介绍了C/A码差分GPS基准站的精确定位的一般方法，着重对在实践中最常用的简单平均方法做了详细分析，针对简单平均方法的不足之外，提出了一种基于精确衰减因子（DOP）加权的卡尔曼滤波方法，实验结果表明，本文提出的C/A码差分GPS基准站定位方法能够有效地提高定位精度。     

Multiple feedback at a single-server station

A single server facility is equipped to perform a collection of operations. The service rendered to a customer is a branching process of operations. While the performance of an operation may not be interrupted before its completion, once completed, the required follow-up work may be delayed, at a cost per unit time of waiting that depends on the type and load of work being delayed. Under some probabilistic assumptions on the nature of the required service and on the stream of customers, the problem is to find service schedules that minimize expected costs. The authors generalize results of Bruno [2], Chazan, Konheim and B. Weiss [4], Harrison [8], Klimov [10], Konheim [11], and Meilijson and G. Weiss [13], using a dynamic programming approach.     

Observational Study of Annual Variations of the Surface Energy Balance Components at Zhongshan Station of Antarctica in 1990

From February 1990 to January 1991, the measurement experiment was carried out at Zhongshan station, East Antarctica. In the experiment, measurements of the surface radiative fluxes and wind, temperature and humidity profiles in the lowest 32 m in the atmosphere boundary layer were made throughout the year. The regime of the surface energy balance was analysed based on the observed data. The conclusion was derived that in warm season (from Nov. to Feb.), large amounts of energy are absorbed by the surface and then transported to the atmosphere in the form of sensible and latent heat, while in cold season (from Mar. to Oct.) continually radiative cooling of the surface occurs.     

离子色谱法测定电厂炉管垢样中的Cl-、SO42-

介绍离子色谱法测定电厂炉管垢样中腐蚀介质Cl^-和SO4^2-的方法，并对使用在线淋洗液发生器与以前配制淋洗液的方法进行了对比，提出了其在应用中的特性。垢样中Cl^-和SO4^2-的相对标准偏差分别为2.7%和2.3%，回收率分别为89.0%-97.8%和91.0%-98.9%。     

Perkin—Elmer公司DSC-2C差示扫描量热仪数据处理站的改进与功能扩展

介绍了对Ｐｅｒｋｉｎ－Ｅｌｍｅｒ公司生产的ＤＳＣ—２Ｃ差示扫描量热仪数据处理站专用计算机原程序进行修改的工作，并与通用微机联用，改进了原数据处理站的输出方式，扩展了数据处理功能。     

Three Dimensional Monitoring of Stack Plume Dynamics by a Scanning Mie Lidar System as a Plume Watchdog Station

A scanning lidar system was developed to watch the nighttime diffusion process of plume from a smokestack of a large incinerator located around 3 km from the system. Observed data sets were visualized as three dimensional images in which could be seen the diffusion pattern from any direction, and this made it easy to investigate the exhaust dynamics. Observation results showed that the original plume extended at least 1.6 km, where there was a residential area, from the smokestack increasing in diameter to about 500 m. High density aerosols originating from the smokestack were measured in that area even at midnight. The lidar system performance as a plume watchdog station was discussed from the standpoint of publichealth-related plume monitoring.