扩增标准电流比的专用电流互感器

介绍了用于扩增标准电流比的专用电流互感器,可分别将１５０／５、３００／５、６００／５和１２００／５等电流比扩增为１６０／５、３１５／５、６３０／５和１２５０／５等新电流比以及将ｎ／５扩增为ｎ／１新电流比。     

Assessing attitudes, beliefs and readiness for musculoskeletal injury prevention in the construction industry

The objectives are to determine attitudes and beliefs among construction workers and supervisors related to taking action to reduce musculoskeletal injuries (MSIs). “Action” stage of change was confirmed if workers in the last 6 months are continuing to take steps to reduce MSIs. Surveys (520 workers; 35% and 171 supervisors; 67%) revealed that more workers are concerned about MSIs (p < 0.05) and are taking action to reduce MSIs (p < 0.05) than supervisors. Workers taking action tended to be younger and less experienced than other workers (p = 0.00). The final multivariate model showed those workers taking action were more likely to be mechanics and general laborers, to have experienced pain within the last week, to be involved in health and safety, to feel that changes aimed at reducing MSIs would be effective, and that injuries are due to adverse work conditions rather than with characteristics of individual workers. This information can be used to target ergonomics interventions in this industry.     

山区河流宽窄相间河段山洪水沙输移2维数值试验

山区河流山洪过程常挟带大量泥沙,并引发河床剧烈变形,尤其是宽窄相间河段河床急剧调整、水位陡涨极易增加展宽河段的洪水淹没风险,深入研究山洪演进的水沙输移及河床变形对于防洪减灾具有重要意义。本文采用二维水沙动力学数值试验探究了上游来沙变化条件下宽窄相间河段水沙输移及河床变形过程。结果表明：当上游来沙充足时,洪水携带泥沙在展宽段淤积、缩窄段冲刷,河床在泥沙输移过程中整体上抬;而当上游没有来沙时,河床整体呈现下切趋势。究其原因,主要在于河道饱和输沙导致河床整体淤抬,而河床淤抬导致上游水位陡涨增加水面比降,床面切应力变大,从而提高河道输沙率,而宽窄河段床面起伏则增大床面形态阻力,促使上游水位上涨;泥沙来量较少时,河床冲刷为主,水位下降、水面比降趋于变缓。     

空分设备自动控制监测系统

本文主要介绍了空分制氮（制氮）设备的自动控制监测系统，通过上位计算机加组态软件配合下位PLC构成整个控制系统的核心部分，系统自动化程度高，使用方便。     

空气透平试验台风源能力计算

通过空气透平级试验台,可研究试验级的效率与速比变化关系曲线、根顶部反动度与速比的变化关系曲线和级反动度、出口角度、出口速度、能量损失系数、级相对内效率等沿叶高分布等,并通过详细流场测试,研究不同叶型及不同流型对二次流的影响,进而研究叶栅通道内的流动损失。阐述了建立空气透平试验台所需风源的能力和试验级功率等的计算方法,并以600MW及1000MW机组的中压末级、高压末级作为模型试验级,计算了单级空气透平试验强所需风机的流量和压头,以及水力测功器的转速及测功范围。     

新疆某难选金矿石选矿试验研究

对新疆某碳质细粒浸染型难选金矿进行选矿试验研究,结果表明,以硫酸铜为活化剂、丁基黄药和丁铵黑药为捕收剂,采用阶段磨矿-阶段浮选的流程,开路试验得到金品位77．42g／t、金回收率63．10％的较好浮选指标。     

新疆某难选金矿石选矿试验研究

对新疆某碳质细粒浸染型难选金矿进行选矿试验研究,结果表明,以硫酸铜为活化剂、丁基黄药和丁铵黑药为捕收剂,采用阶段磨矿-阶段浮选的流程,开路试验得到金品位77.42 g/t、金回收率63.10%的较好浮选指标。     

胡状集断块油田高含水期挖潜方法探讨

针对非均质油田高含水开发后期开发调整难度大、单井措施效益差的问题,以胡状集油田为例,通过剩余油控制机理研究,刻画剩余油分布状况,并总结近几年高效措施的特点,归纳若干不同的挖潜方式,旨在探讨如何由提高单井产能入手,提高区块产量,改善开发效果。     

一类动态规划问题的解法与算法

本文给出了终止段未知的离散动态规划问题的解法和算法，并且结合经济问题的实际应用以及解法。     

The effect of a surfactant on mixer—settler operation

A single stage mixer—settler was used to investigate the effect of surfactant on the mass transfer rate in the system water—HNO₃—30 vol.% TBP/dodecane. The interfacial tension of this system first falls then rises with increasing sodium lauryl sulphate (SLS) concentration. The addition of SLS makes the stage efficiency, which is closely related to k_ha, the product of the individual mass transfer coefficient of HNO₃ in the aqueous phase, and average interfacial area per unit volume of mixing chamber, to increase significantly due to an increase in the value of a. A maximum k_ha value of 0.53 litres^?1, a minimum value of interfacial tension, and phase inversion which converted the aqueous phase from continuous to dispersed were observed at around the critical micellar concentration (100 parts 10^?6) of SLS in the system of an aqueous to organic phase ratio of 0.2.