激光加工技术在珠宝首饰业中的应用

激光加工技术在珠宝首饰业中的应用越来越广泛。介绍了该技术的基本特点以及其在珠宝首饰业中的典型应用现状。这些技术涉及激光焊接、激光快速原型技术、激光打标、激光雕刻和激光切磨钻石等领域。激光焊接比传统的焊接技术具有显著的优点;快速原型技术的引入大大缩短了从首饰图样到制出原版的时间;激光打标和激光雕刻的使用丰富了首饰表面处理的手段,可进一步满足首饰个性化需求;激光切磨钻石原石可达到最小的损耗。激光加工技术在珠宝首饰业中发挥着越来越重要的作用。     

油库自动化计量软件系统应用分析与改进实现

对国内外众多油库目前投入使用的各种计量系统进行分析,剖析其各自的优缺点,并结合国际国内的现场总线技术的发展趋势,给出一个更加合理的现代化自动计量系统的系统构架,并使用Ｃ＃和ＳＱＬＳｅｒｖｅｒ实现软件系统．     

Modelling combined open channel flow by artificial neural networks

Combined open channel flow is encountered in many hydraulic engineering structures and processes, such as irrigation ditches and wastewater treatment facilities. Extensive experimental studies have conducted to investigate combined flow characteristics. Nevertheless, there is no simple relationship that can fully describe the velocity profiles in a turbulent flow. The artificial neural network (ANN) has great computational capability for solving various complex problems, such as function approximation. The main objective of this study is to evaluate the applicability of the ANN for simulating velocity profiles, velocity contours and estimating the discharges accordingly. The velocity profiles measured by an acoustic doppler velocimeter in the open channel of the Chihtan purification plant, Taipei, with different discharges at fixed measuring section and different depths are presented. The total number of data sets is 640 and the data sets are split into two subsets, i.e. training and validation sets. The backpropagation algorithm is used to construct the neural network. The results demonstrate that the velocity profiles can be modelled by the ANN, and the ANN constructed can nicely fit the velocity profiles and can precisely predict the discharges for the conditions investigated. Copyright © 2005 John Wiley & Sons, Ltd.     

Sheath formation inOscillatoria agardhii Gomont

Sheath formation was observed in laboratory culturedO. agardhii. The sheath serves as a protective cover against bacteria. Some comments on sheath formation by this alga are given.

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Zusammenfassung Scheidenbildung beiOscillatoria agardhii Gomont Im Kulturmaterial vonOscillatoria agardhii Gomont wurde die Bildung von Scheiden beobachtet. Diese dienen als Schutz gegen Bakterien. Es werden weitere überlegungen über die Scheidenbildung bei dieser Alge angestellt.

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Résumé Formation de gaines chezOscillatoria agardhii Gomont La formation d’une gaine chezOscillatoria agardhii Gomont fut observée dans une culture. Ces gaines protègent les algues contre les bactéries. Des considérations ultérieures sont faites sur le phénomène des gaines chez cette algue.

     

Evaluation of undrained shear strains in multi-directional horizontal shaking

The evaluation of shear strains under multi-directional shaking is an important issue in interpreting dynamic soil behavior for both laboratory physical modeling and in situ monitoring. Shear strain components evaluated from Cartesian coordinates in undrained conditions have limitations to fully capture the coupled shear strain-pore pressure responses with an individual expression. In the present study, radial and rotational shear strain components derived from particle motions described with cylindrical polar coordinates are proposed. The proposed radial and rotational shear strains are verified with data from a bi-directional laminar shear box and a free field downhole array. Comparison results show that the proposed expressions of shear strain effectively capture the coupled strain-pore pressure responses in terms of the frequency content, amplitude variation, phase difference, and oscillation behavior. Comparison results reveal that the radial shear strain is the dominant shearing mode and the amplitude of the rotational shear strain is only 6.5–14.5% of the radial component. This provides quantitative data for the correction factor for multi-directional shaking and suggests that a simple shear system capable of inducing the radial shear strain on the vertical plane is a better approach than other shearing modes for physically modeling the behavior of soil subjected to undrained seismic loadings.     

Assessing Performance of Tomo-SAR and Backscattering Coefficient for Hemi-Boreal Forest Aboveground Biomass Estimation

Tomo-SAR technique has been used for hemi-boreal forest height and further forest biomass estimation through allometric equation. Backscattering coefficient especially in longer wavelength (L- or P-band) is thought as a useful parameter for hemi-boreal forest biomass retrieval. The aim of this paper is to assess the performance of vertical backscattering power and backscattering coefficient for hemi-boreal forest aboveground biomass (AGB) estimation with airborne P-band data. The test site locates in southern Sweden called Remningstorp test site, and the in-situ forest AGB ranges from 14 t/ha to 245 t/ha at stand level. Multi-baseline P-band Pol-InSAR data in repeat-path mode collected during March and May in 2007 at Remningstorp test site was used. We found that the correlation coefficient (R) between backscattering coefficient of P-band HH polarization and the in-situ forest biomass reached 0.87. The R for P-band VV backscattering power at 5 m is 0.71 and 10 m is 0.72. Backscattering coefficient in HH polarization and vertical backscattering power at 5 m and 10 m were applied to construct a model for hemi-boreal forest AGB estimation by backward step-wise regression and cross-validation approach. The results showed that the estimated forest AGB ranges from 19 to 240 t/ha, and the constructed model obtained a higher R and smaller RMSE, the value of R is 0.91, RMSE is 30.43 t/ha at Remningstorp test site.     

基于网站群理念和架构的国家土地督察网站群建设实践

随着政府网站的建设和发展,网站群已成为电子政务发展的一种新模式。本文对立足于网站群理念和架构的国家土地督察网站群的建设实践进行了介绍,详解了国家土地督察网站群建设思想、建设原则、总体框架、技术路线、信息分类和栏目规划等。国家土地督察网站群为政府网站群的建设积累了有益经验。     

三频精密单点定位观测模型初探

三频观测值为导航定位提供了更多的观测值组合选择。在利用载波相位三频线性组合消除一阶电离层误差的基础上,对组合模糊度为实数和整数两种情况下的二阶电离层误差及观测噪声水平进行了分析,获得了几种适用于精密单点定位的三频观测值组合。     

The Data Collection and Process System for RDT-10000 Type Rock High Pressure Dynamic Triaxial Machine

A data collection and process system is developed for RDT-10000 Type Rock Dynamic Triaxial Machine with High pressure, this system is supported by several subroutines in 6502 assembly language, which is of high-speed, flexibility, multi-functions.