众多电力公司正在建设信息高速公路

众多电力公司正在建设信息高速公路赫伯特·Ａ·卡凡诺（ＨｅｒｂｅｒｔＡ．Ｃａｖａｎａｕｇｈ）著许荣昌，丛玉译孙佐一校在美国国内各行各业中，公用电力公司最迫切需要企业专用的“实时”通信设施，电力工业在非常大的程度上依靠广泛的内部通信系统来监视、控制、协调...     

Finite-element analysis of vibrational modes in piezoelectric ceramic disks

The natural vibrational modes of axially symmetric piezoelectric ceramic disks have been calculated by the finite-element method. The disks are of the type used as active elements in compressional wave ultrasonic transducers, and are electrically polarized in thickness with full electrodes on the disk's major faces. To optimize disk geometry for ultrasonic transducer application, the dependence of the vibrational modes on the disk diameter-to-thickness ratio for ratios from 0.2 (a tall cylinder) to 10.0 (a thin disk) has been studied. Series and parallel resonance frequencies for each of the modes are determined through an eigenfrequency analysis, and effective electromechanical coupling coefficients are calculated. The modal displacement fields in the disk are calculated to determine the physical nature of each mode. An analysis of the complete spectrum of piezoelectrically active modes as a function of diameter-thickness ratio is presented for the ceramic PZT-5H, including and identification of radial, edge, length expander, thickness shear, and thickness extensional vibrations. From this analysis, optimal diameter-to-thickness ratios for good transducer performance are discussed.     

影响汽车燃油胶管性能的新因素

对于中等丙烯腈含量的丁腈胶燃油胶管胶料来讲,燃油的渗漏性系随丙烯腈含量增加而提高。添加低分子量的醇作为燃油的增量剂,会对胶料的溶胀和渗漏产生不良影响,当醇的含量为10～20%时,此种不良影响最明显,丁腈胶能耐纯酒精的作用。为改善辛烷值而添加的用量在7%以下的叔丁醇,对丁腈胶并没有不良的影响。对于高芳烃含量的燃油,高丙烯腈含量的丁腈胶以及丁腈胶-聚氯乙烯并用胶具有较低的渗漏性以及较好的耐溶胀性、而且,在醇改性燃油中的耐溶胀性亦有改善.羧基丁腈胶的燃油渗漏性稍低于一般的丁腈胶。以高丙烯腈含量的丁腈胶以及实际可能达到的最高丙烯腈含量的丁腈胶与聚氯乙烯并用以及羧基丁腈胶与聚氯乙烯并用,作为中等丙烯腈含量的丁腈胶的内衬层而制成双层燃油胶管可以成为获得合格的渗漏性和耐低温性能的途径。     

Design of small-area multi-bit antifuse-type 1 kbit OTP memory

A multi-bit antifuse-type one-time programmable (OTP) memory is designed, which has a smaller area and a shorter programming time compared with the conventional single-bit antifuse-type OTP memory. While the conventional antifuse-type OTP memory can store a bit per cell, a proposed OTP memory can store two consecutive bits per cell through a data compression technique. The 1 kbit OTP memory designed with Magnachip 0.18 μm CMOS (complementary metal-oxide semiconductor) process is 34% smaller than the conventional single-bit antifuse-type OTP memory since the sizes of cell array and row decoder are reduced. And the programming time of the proposed OTP memory is nearly 50% smaller than that of the conventional counterpart since two consecutive bytes can be compressed and programmed into eight OTP cells at once. The layout area is 214 μm × 327 μm, and the read current is simulated to be 30.4 μA. Foundation item: Project supported by the 2nd Stage of Brain Korea; Project supported by the Korea Research Foundation     

Evaluation of the pollution load discharged at an upstream industry--Egypt--and methods for its reduction

Oil exploration in Egypt is a major contributor to the national Gross Domestic Product (GDP). With 50-65% of the oil resources located in the Gulf of Suez (GoS) region, the impact of such activity upon the region's water environment and its quality cannot be overlooked because of the volume of effluent generated. The objective of this study (September 2000-September 2001) was to assess the impact of a 650,000 barrels/day (bl/d) (100,000 m3/d) effluent arising from a major oil exploration site located south of GoS upon the local water environment. Another objective was to identify the pollutant contents amenable for reduction relative to the new Egyptian regulations. This was achieved by the characterization of the main contributing streams and the identification of the final effluent parameter constraints relative to the type of injection waters used. Subsequent investigations for the reduction of these contents were conducted on site and the results obtained are reviewed herewith.     

Multiple responses analysis and modeling of Fenton process for treatment of high strength landfill leachate

Landfill leachate is one of the most recalcitrant wastes for biotreatment and can be considered a potential source of contamination to surface and groundwater ecosystems. In the present study, Fenton oxidation was employed for degradation of stabilized landfill leachate. Response surface methodology was applied to analyze, model and optimize the process parameters, i.e. pH and reaction time as well as the initial concentrations of hydrogen peroxide and ferrous ion. Analysis of variance showed that good coefficients of determination were obtained (R2 > 0.99), thus ensuring satisfactory agreement of the second-order regression model with the experimental data. The results indicated that, pH and its quadratic effects were the main factors influencing Fenton oxidation. Furthermore, antagonistic effects between pH and other variables were observed. The optimum H2O2 concentration, Fe(II) concentration, pH and reaction time were 0.033 mol/L, 0.011 mol/L, 3 and 145 min, respectively, with 58.3% COD, 79.0% color and 82.1% iron removals.     

TimeLapseAnalyzer: multi-target analysis for live-cell imaging and time-lapse microscopy

The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid in biomarker discovery and diagnostic decisions. Given the vast amount of image- and time-series data produced by modern microscopes, automated analysis is a key feature to capitalize the potential of time-lapse imaging devices. To provide fast and reproducible analyses of multiple aspects of cell behaviour, we developed TimeLapseAnalyzer. Apart from general purpose image enhancements and segmentation procedures, this extensible, self-contained, modular cross-platform package provides dedicated modalities for fast and reliable analysis of multi-target cell tracking, scratch wound healing analysis, cell counting and tube formation analysis in high throughput screening of live-cell experiments. TimeLapseAnalyzer is freely available (MATLAB, Open Source) at http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/tla.