f—x域内提高地震资料的信噪比

在 f-x 域,地震记录可以表示成有限个调频调幅正弦波的叠合,叠合的结果是一个连续且光滑的函数。我们可以用一个简单的 n 次多项式去逼近这个函数。本文提出了一种在 f-x 域用最小平方拟合原理消除随机噪声的新方法,并证明了在噪声为自噪以及空间采样足够密的条件下,拟合结果与噪声无关,即 f-x 域最小平方拟合处理可以有效地消除记录上的随机白噪,而对有效信号的破坏甚微。由于理论上允许振幅值及同相轴形态在空间上发生变化,因而该方法不具有混波作用,是高分辨率处理的理想工具。     

山迪亚国家实验室半导体桥(SCB)应用研究概述

山迪亚国家实验室研究的半导体桥（ＳＣＢ）是一种成熟的技术，现由山迪亚用户用于不同用途。由于需要为系统提供体积小、重量轻、成本低，并要求少量电能作用的爆炸组件，由于本报告的目的，我们规定爆炸组件是发火装置和爆炸元件的组合。为此，由于常规点火系统不能满足用户严格的尺寸、重量和能量要求，我们设计并正在研究包括从山迪亚应用的以烟火点火器的ＳＣＢ应用。在本报告中，我们介绍了为用户设计的具有具体实例系统的ＳＣ     

膜淤塞对微滤的油水分离性能的影响

本文报道了用微滤分离乳化含油废水的研究，利用微滤过程中膜淤塞的特点，显著地提高了油水的分离效率，同时维持较高的水透过率。文章讨论了油水分离的机理，并根据实验结果提出流体中适当的油粒粒径分布，是获得较好分离效果的重要条件。本研究表明了在一定下，可以用水透过率较高、操作成本降低的微滤取代超滤。     

Experimental evidence for mode shape influence on acceleration-induced frequency shifts in quartz resonators

Experimental results are presented to support the hypothesis that the shape and location of the active region of vibration in a thickness shear mode quartz resonator are the dominant factors in determining the acceleration sensitivity of the resonator. The shape and location of the mode in a real world resonator vary sufficiently from unit to unit (due to material and processing variations) that all other considerations are overwhelmed. It is shown experimentally that the mode shape and/or location can be trimmed with energy trapping by judicious addition or subtraction of mass to produce resonators with improved acceleration sensitivity.     

On delay adjustment for dynamic load balancing in distributed virtual environments

Distributed virtual environments (DVEs) are becoming very popular in recent years, due to the rapid growing of applications, such as massive multiplayer online games (MMOGs). As the number of concurrent users increases, scalability becomes one of the major challenges in designing an interactive DVE system. One solution to address this scalability problem is to adopt a multi-server architecture. While some methods focus on the quality of partitioning the load among the servers, others focus on the efficiency of the partitioning process itself. However, all these methods neglect the effect of network delay among the servers on the accuracy of the load balancing solutions. As we show in this paper, the change in the load of the servers due to network delay would affect the performance of the load balancing algorithm. In this work, we conduct a formal analysis of this problem and discuss two efficient delay adjustment schemes to address the problem. Our experimental results show that our proposed schemes can significantly improve the performance of the load balancing algorithm with neglectable computation overhead.     

Dielectric properties of ultrafine grained BaTiO(3)

The dielectric constant and spontaneous polarization of fine-grained BaTiO(3) prepared from powder produced by metalloorganic decomposition technology were studied. The room-temperature dielectric constant of BaTiO(3) was found to increase sharply with increase in grain size, reach a maximum at about 0.4 mum, and decrease with further increase in grain size. Spontaneous polarization continuously decreased with decrease in grain size. A model is proposed to explain the grain size dependence of the dielectric constant.     

High K BaTiO(3) films from metalloorganic precursors

Crack-free and dense BaTiO(3) films 4 to 8 mum thick were prepared by spinning a solution of metalloorganic precursors onto an appropriate substrate, and firing and annealing the film in air at certain temperatures to obtain appropriate grain sizes. The electrical properties of the films were studied as a function of grain size, temperature, frequency, and DC bias. Films with a grain size of 0.2 mum showed ferroelectric properties similar to bulk BaTiO(3).