Fractal-like Matrices

We introduce special sparse n×n-matrices (n=2 ^k ) containing up to 3 ^k ≈n ^1.585 nonzero elements. Their structure is inherited from the famous Sierpinski triangle and is not sensitive to matrix multiplication and inversion. The arithmetical complexity of taking product or inverse of such matrices is proved to be O(n ²).     

^28Si同位素应用背景及分离研究现状概述

文章对^28Si同位素的应用背景进行概述，并介绍分离。^28Si同位素的几种具体方法和国内外的分离研究现状，认为同位素纯^28Si材料将会在未来的高级微电子芯片等领域中获得很好的发展。     

Thermal Diffusivity Measurement of Isotopically Enriched 28-Si Single Crystal by Dynamic Grating Radiometry

In the past decade it has been suggested that the isotopic enrichment of 28-silicon enhances its thermal properties. Thus, 28-silicon is suitable as a heat sink in large-scale integrated circuits. Although some studies have focused on the measurement of isotopically enriched silicon's thermal properties, accurate experimental data are not sufficient because of this material's high conductivity and large heat capacity which make measurement difficult. However, the dynamic grating radiometry (DGR) method has been successfully developed to measure the thermal diffusivity of 28-silicon. In the DGR method, the sample is heated by interference of two pulsed laser beams, and the temperature decay is monitored by an infrared detector. By analyzing the temperature changes of the peaks and valleys of the thermal grating, the thermal diffusivities parallel and perpendicular to the sample surface are obtained simultaneously. In this paper, the optimum conditions of the experimental setup for measuring isotopically enriched silicon are discussed. The comparison of thermal diffusivities between 28-silicon and natural silicon (with a thickness of about 100m) is presented, and the applicability of DGR to isotope engineering is reported.     

How to visualize the spider mite silk?

Tetranychus urticae (Acari: Tetranychidae) is a phytophagous mite that forms colonies of several thousand individuals. Like spiders, every individual produces abundant silk strands and is able to construct a common web for the entire colony. Despite the importance of this silk for the biology of this worldwide species, only one previous study suggested how to visualize it. To analyze the web structuration, we developed a simple technique to dye T. urticae'silk on both inert and living substrates. Fluorescent brightener 28 (FB) (Sigma F3543) diluted in different solvents at different concentrations regarding the substrate was used to observe single strands of silk. On glass lenses, a 0.5% dimethyl sulfoxide solution was used and on bean leaves, a 0.1% aqueous solution. A difference of silk deposit was observed depending the substrate: rectilinear threads on glass lenses and more sinuous ones on bean leaves. This visualizing technique will help to carry out future studies about the web architecture and silk used by T. urticae. It might also be useful for the study of other silk-spinning arthropods. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc.     

低频采油技术及应用效果

介绍了低频采油技术的作用机理及其基本作业参数的选择，以两口采油井和一口注水井的低频脉冲处理情况为例，分析了其作用效果及孤东油田适合于低频处理的注、采井的油藏条件。     

高强冷弯薄壁型钢龙骨式住宅结构轴压立柱研究

高强冷弯薄壁型钢龙骨式结构是一种新型结构形式,主要适用于3层及3层以下的建筑。材料较高的屈服强度(fy=550MPa)使得此类构件有较高的承载能力,但在目前我国的冷弯薄壁钢结构设计规范中没有对这类高强材料的计算、设计方法。通过比较中国规范、澳大利亚相应规范和试验研究结果,探讨轴压立柱计算方法中的问题。     

FST28-35��ͨ���������Ԫ����

本文介绍了FST28-35四通壳体所进行的有限元数值分析。该分析提供了四通壳体在试验压力下的应力与位移分布,从绘出的应力图中可以看出应力集中区域和全局应力分布状况。     

KZ-28型可控震源气源部分改进

KZ-28型可控震源的气路在冬季施工过程中常出现洁冰现象。通过对气路中的空压机、空气干燥器、油水分离器和自动排水阀进行分析，发现组成气路的器件功能重叠、元件工作时相互干扰以及气路中不能连续干燥等问题。通过对气路的气源部分进行改进设计，对空气干燥器进行改造，较好地解决了以上问题。     

KZ-28震源DGPS数据分析与质量控制

本文具体描述了KZ-28可控震源的GPS作业方式、要求、质量控制难点、作业数据检验和质量控制方法,并通过对道达尔试验项目KZ-28震源DGPS作业中存在的数据不匹配等问题进行了分析和研究,探索出其数据处理和质量控制的方法,成功地解决了影响生产的瓶颈问题,确保了地震勘探合作项目的顺利进行。