大型往复式压缩机的配管设计

大型往复式压缩机功率大、占地面积大,管道振动问题也更为突出。笔者结合实践经验,对大型往复式压缩机的配管设计进行探讨,说明了平面布置与管道防振设计的密切关系,并介绍了管道防振设计的方法和步骤,以及相对简单的复杂管系气柱固有频率的转移矩阵计算方法。     

载体比表面积及孔径对Nb_2O_5/α-Al_2O_3催化剂酸性及反应性能的影响

采用浸渍法制备了Nb2O5/α-A l2O3催化剂(简称催化剂)并用于环氧乙烷水合制乙二醇的反应,通过控制α-A l2O3载体中致孔剂的含量来调变载体的孔径、孔分布及比表面积;采用吡啶吸附红外光谱、氨程序升温脱附法研究了载体的比表面积及孔径对催化剂酸性及反应性能的影响。实验结果表明,产物的选择性受扩散因素及催化剂酸性的影响,而催化剂的酸量、酸密度可以通过载体的孔径及比表面积的变化加以调控。比表面积较小及孔径较大的载体对催化剂催化环氧乙烷水合制乙二醇的反应较为有利。当载体的比表面积小于0.80m2/g、孔径为4.00~8.00μm时,在反应温度160℃、反应压力1.5M Pa、n(H2O)∶n(EO)=22、液态空速25h-1的条件下,环氧乙烷的转化率大于99.8%,乙二醇的选择性超过89.9%。     

多分量波场的矢量法叠前深度偏移技术

本文研究了二维各向同性介质中两分量记录的矢量法叠前深度偏移方法———叠前逆时深度偏移方法。首先从弹性波波动方程出发,在交错网格空间中推导了各向同性介质中弹性波逆时延拓的高阶有限差分格式;然后从程函方程出发,采用逆时差分格式求解地下各点的地震波走时。为确保算法满足地震波传播的因果性条件及其对复杂模型的适应性,用扩展波阵面算法追踪波前并搜索全局极小,以上述方法的计算结果作为弹性波逆时偏移的成像条件,实现二维多分量资料的叠前逆时深度偏移。模型试算和实际单炮记录试验表明,叠前逆时深度偏移方法考虑了地震波的矢量特征,是一种有效的矢量波场处理技术。     

利用中石油域用户认证系统实现数据存储备份

系统面向中石油域用户提供了安全、高速的数据传输服务.实现了数据传输DES加密、用户登录LDAP限制、系统安全审计、空间容量扩容等功能.充分利用SAN网络光存储设备,同时也为油田网络存储应用的开发提供了成功经验.     

甲烷无氧芳构化研究进展及其工业应用前景

综述了最近20多年来甲烷无氧芳构化催化剂的制备、积炭失活和再生方面的研究进展，特别分析了催化剂再生过程的工程化问题及反应器型式；还根据甲烷芳构化技术产业化的需要，分析了甲烷芳构化技术的发展趋势。     

Finite element piezothermoelasticity analysis and the active control of FGM plates with integrated piezoelectric sensors and actuators

 An efficient finite element model is presented for the static and dynamic piezothermoelastic analysis and control of FGM plates under temperature gradient environments using integrated piezoelectric sensor/actuator layers. The properties of an FGM plate are functionally graded in the thickness direction according to a volume fraction power law distribution. A constant displacement-cum-velocity feedback control algorithm that couples the direct and inverse piezoelectric effects is applied to provide active feedback control of the integrated FGM plate in a closed loop system. Numerical results for the static and dynamic control are presented for the FGM plate, which consists of zirconia and aluminum. The effects of the constituent volume fractions and the influence of feedback control gain on the static and dynamic responses of the FGM plates are examined. Received: 13 March 2002 / Accepted: 5 March 2003 The work described in this paper was supported by a grant awarded by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. CityU 1024/01E).     

大功率CO2激光器脉冲电源研究

本文论述了直流高压与高频脉冲电源相叠加，构成高频、高压脉冲电源，并使其对CO2激光器进行放电实验，研究了同条件下的放电参数与功率。     

Occupational injuries among working adolescents in New York State

OBJECTIVE: To determine the number, distribution, determinants, and health consequences of occupational injuries among working adolescents in New York State. DESIGN: A retrospective, population-based analysis of New York State workers' compensation award data and the Annual Demographic File, a supplement to the US Bureau of the Census Current Population Survey. PARTICIPANTS: Adolescents, aged 14 through 17 years, who received workers' compensation awards for occupational injury from 1980 through 1987. MAIN OUTCOME MEASURES: (1) Numbers, types, and rates of occupational injuries in working adolescents by age, sex, industry, and occupation; (2) health consequences of injury, especially disability and death; and (3) secular trends in injury award rates. RESULTS: A total of 9656 adolescents were compensated for occupational injuries; 4201 compensated adolescents (43.5%) suffered permanent disability; 31 working adolescents died. The annual mean rate of compensated occupational injury was 28.2 per 10,000 adolescent workers. Rates were higher in males than in females and ranged from 8.2 per 10,000 in 14-year-old male workers to 46.8 per 10,000 in 17-year-old male workers. Highest rates by industry were seen in manufacturing (49.0/10,000 adolescent workers) and agriculture (46.2/10,000). Unskilled labor was the most dangerous occupation (52.3/10,000). CONCLUSION: Occupational injuries are a substantial and underrecognized contributor to the continuing epidemic of injury among adolescents.     

一种实现最佳用户检测的非线性优化神经网络

本文提出并讨论了实现码分多址（CDMA）系统上最佳多用户检测（MUD）的一种神经网络方法。该方法通过将最佳多用户检测视为非线性优化组合问题，利用神经网络能有效求解非线性优化问题的优势，导出了一种非线性优化神经网络来实现最佳多用户检测，理论分析和计算机模拟表明，所提出的神经网络具有可实时应用的动态性能和较传统方法优越得多的误码率性能和抗多址干扰的性能。     

双极关键工艺的在线统计分析

采用了双极晶体管作为双极工艺的测试结构,将在线工艺的统计分析理论应用于双极工艺,研制了双极工艺的统计分析软件。最后给出了双极工艺的某些分析结果。