TEQC软件对GPS数据质量的评定及软件界面的开发

本文主要介绍用于GPS数据转换、编辑和质量检查的共享软件TEQC(Translate／Edit／Quality Check)。作为例子，对一GPS数据进行质量检查。并针对TEQC软件人机交互性差的缺点，进行了软件界面程序的初步开发。     

VLBI中性大气折射延迟的研究进展——天顶延迟的改正模型

大气传播延迟是空间大地测量技术的主要误差源,特别是在低高度角的观测情况下尤其如此。因此,大气折射改正的研究仍然是当代新空间技术研究的重要课题之一,完善大气折射理论不仅可以改善新技术的归算精度,而且有希望降低仪器的观测截止角,提高仪器的使用效应。详细地综述了对流层大气折射延迟研究的基本概念和理论方法,探讨了对不同精度要求和不同高度截至角的VLBI观测可以采用的大气折射延迟模型的计算方法。     

大气潮给对流层延迟影响的探讨

探讨了大气潮对GPS信号对流层延迟改正的影响，提出大气潮的周期性涨落会给对流层湿层延迟带来误差，在更高精度的导航定位、时间传递、电波传播中应该考虑修正。     

Discrete‐time variable structure control method for seismic‐excited building structures with time delay in control

The discrete‐time variable structure control method for seismically excited linear structures with time delay in control is investigated in this paper. The control system with time delay is first discretized and transformed into standard discrete form which contains no time delay in terms of the time delay being integer and non‐integer times of sampling period, respectively. Then the discrete switching surface is determined using ideal quasi‐sliding mode and discrete controller is designed using the discrete approach‐law reaching condition. The deduced controller and switching surface contain not only the current step of state feedback but also linear combination of some former steps of controls. Numerical simulations are illustrated to verify the feasibility and robustness of the proposed control method. Since time‐delay effect is incorporated in the mathematical model for the structural control system throughout the derivation of the proposed algorithm, system performance and dynamic stability are guaranteed. Copyright © 2002 John Wiley & Sons, Ltd.     

应用GPS资料反演南极大气可降水量的试验分析

本文研究的主要内容是从对流层天顶延迟来反演大气中的可降水量。利用我国长城和中山两站 1 998、1 999、2 0 0 0年参加全南极GPS国际联测所取得的南极地区的GPS数据 ,组成各期GPS网 ;采用高精度的GAMIT/GLOBK软件进行基线解算和网平差处理 ,使用多种数据处理方案 ,得到各时段两站对流层的天顶总延迟值 ,采用了Saastamonien和Hopfield两种模型分别进行天顶静力学延迟的解算来分离天顶静力学延迟。从两站的历史气象资料出发 ,通过回归计算得到适合两站 1、2月份的转换系数K ;然后进行天顶湿延迟至可降水量的转换 ,结合现场的气象资料进行对比分析。各期数据均取得了较为满意的结果。     

Real-time hybrid experimental system with actuator delay compensation and its application to a piping system with energy absorber

A real-time hybrid experimental method, in which output from an actuator-excited vibration experiment and response calculation are combined on-line and conducted simultaneously in real time, is being developed as a new seismic experimental method for structural systems. In real-time hybrid experiments, however, there is an inevitable actuator-response delay, which has an effect equivalent to negative damping. To solve this problem, a real-time hybrid experimental system (including an actuator-delay compensation method) was developed. And seismic experiments were conducted in order to demonstrate the advantages of this system. Experimental results obtained using the developed hybrid experimental system were compared with exact results obtained using shaking-table experiments, and it was found that the two experimental methods gave almost identical results. It can therefore be concluded that the structural response can be obtained precisely by using the developed hybrid experimental system. Comparison of these experiments showed the advantages of the hybrid experiments; that is, they are simple and economical. This is because the hybrid experiment requires only a small structure as the excitation model, while a shaking-table experiment must consider the whole structural system. Copyright © 1999 John Wiley & Sons, Ltd.     

地基GPS技术用于气象遥感学的初步研究

本文用ＢＥＲＮＥＳＥ软件对我国五处ＧＰＳ跟踪站的部分观测数据作了处理,得出各站上空的对流层天顶延迟量初步结果,并分析了将地基ＧＰＳ技术应用于气象遥感学急待解决的问题。     

大庆台网记录地震震相滞后问题的研究

本文主要分析了大庆台网记录地震Ｐｇ震相滞后的现象,探讨大庆台网Ｐｇ震相的滞后程度及引起震相滞后的原因。     

Ecohydrologic separation alters interpreted hydrologic stores and fluxes in a headwater mountain catchment

Recent studies have demonstrated that compartmentalized pools of water preferentially supply either plant transpiration (poorly mobile water) or streamflow and groundwater (highly mobile water) in some catchments, a phenomenon referred to as ecohydrologic separation. The omission of processes accounting for ecohydrologic separation in standard applications of hydrological models is expected to influence estimates of water residence times and plant water availability. However, few studies have tested this expectation or investigated how ecohydrologic separation alters interpretations of stores and fluxes of water within a catchment. In this study, we compare two rainfall‐runoff models that integrate catchment‐scale representations of transport, one that incorporates ecohydrologic separation and one that does not. The models were developed for a second‐order watershed at the H.J. Andrews Experimental Forest (Oregon, USA), the site where ecohydrologic separation was first observed, and calibrated against multiple years of stream discharge and chloride concentration. Model structural variations caused mixed results for differences in calibrated parameters and differences in storage between reservoirs. However, large differences in catchment storage volumes and fluxes arise when considering only mobile water. These changes influence interpreted residence times for streamflow‐generating water, demonstrating the importance of ecohydrologic separation in catchment‐scale water and solute transport.     

单巢类轮虫有性生殖的研究进展与展望

作为轮虫动物门的主体,单巢类轮虫是淡水浮游动物的重要组成部分.它们通常作为一类主要的初级消费者在淡水生态系统中起着重要作用,因而深入了解它们在自然水体中的种群动态及其决定机制对淡水生态系统理论与应用研究都有重要意义.作为一类具有典型周期性孤雌生殖生活史的动物,有性生殖的发生和进化策略对其种群动态和进化都有重要影响,因而单巢类轮虫有性生殖的机理和进化研究一直是轮虫学研究领域的一个核心内容.本文就当前单巢类轮虫有性生殖的主要研究进展,包括其发生机理、信息素、理论模型、影响因素和相关实证研究等进行了系统综述;特别就单巢类轮虫有性生殖策略的三个理论模型:"bang-bang"模型、中等有性生殖比率模型和非延迟的有性生殖模型进行了详细论述.此外,本文还对影响单巢类有性生殖的内外源因素进行了总结,主要的外源因素包括食物的浓度及种类、温度、盐度和特殊的细菌等,而主要的内源性因素则包括母体年龄、食物浓度诱导的跨代母系效应、延迟的有性生殖和其他一些潜在的母系效应因素等.其中,因为延迟的有性生殖现象广泛存在且可能是轮虫物种共存或克隆共存现象的一种潜在解释,所以就此现象的理论模型、机理和实证研究等方面进行了深入讨论.另外,本文还简要讨论性比率资源分配与单巢类轮虫有性生殖的关系.最后,对未来几个可能的热点方向简单评述,以期为国内轮虫学和相关方面的研究提供帮助.