应用核示踪物评价洗矿槽回收金的效果

在保证非常高的总砂金回率的情况下，洗矿槽能得到比其它重力选矿机高得多的富集比。洗矿槽工作可靠，价格便宜，操作简便，这就是为什么这种洗矿槽目前难以舍弃，并仍然是加拿大育突河地区最重要的砂金选矿设备的原因。     

SIMILARITY LAW OF FLUCTUATING PRESSURE WITHIN HYDRAULIC JUMP AREA

Through a series of model tests of five scales for 2-D free hydraulic jump, the da-ta of fluctuating pressure acting on the floor level within the hydraulic jump were obtained. Dur-ing the experiments, Froude number varied from 2.94 to 8.61, and Reynolds number rangedfrom 2×10~4 to 6×10~5. Experiment results indicate that the amplitude scale of fluctuating pres-sure is the length scale of model, i. e. P'=L, which agrees with gravity similarity law: Thefrequency scale of the fluctuating pressure is a unity i. e., f=1, which does not satisfy thegravity similarity law.     

THE FLOW PRODUCED IN PARTICLE-SUSPENSION BY AN INFINITE ROTATING DISK:SERIES SOLUTION

To the flow produced in particle-suspension by a rotating disk of infinite extent,the asymptotic behavior at infinity is analyzed.A corresponding series solution is presented.It isshown that this approach yields widely valid solutions of high accuracy for all the cases in whichthat suction or weak injection at the disk surface exists.For the cases that strong injection or par-ticle-free band exists,the series method fails.     

TURBULENCE MEASUREMENT INSTRUMENT WITH A SILICON PIEZORE-SISTANCE BEAM

A newly developed turbulence measurement instrument is introduced in the paper.The transducer of the device is based on the principle of the effect of silicon piezoresistance that isintegrated in a Wheatstone bridge on a pure silicon beam. At one end of the beam, a small lightball is installed as the target forced by the water flow. The other parts are prevented from thewater flow with a sophisticated stainless steel tube. The instrument can be used to measure turbu-lent velocities either in clear Water or in flows bearing hyperconcentration of sediment. It can al-so be used to measure velocities in both glass flume and model experiments as well as in pipe ex-periment by being mounted in a special way.     

稀释剂和载体

为了使农药的浓度降低到仅对靶标具有一定的毒性水平,需将其用惰性物质进行稀释,根据用途与需要加工成粉剂、可湿性粉剂、颗粒剂、乳油和悬浮剂等各种“农药制剂”。其中,在世界所有农药制剂产品中,粉剂和水分散性粉剂占有主要地位。为了制取这些制剂,往往用粘土及相关的水合硅铝酸盐矿物质为载体和稀释剂。这些矿物除了能降低农药浓度外,还可赋予农药一定的悬浮性和密度等。由于它们具有吸附能力,由此可使农药包含于它     

On the Realization of Current－Mode Continuous－Time Operational Transconductance Capacitance Filter

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国际镍公司自动运输汽车的设计、研制和应用

已研制成功一种无人驾驶的自动汽车,用于小斯托比矿山运输原矿。这种自动运输汽车的载重量为70t,用架线系统供电,结合计算机控制系统控制汽车。设计这种汽车的目的是凡在不宜直接用带式输送机的地方,运用这种汽车可提供能力大、生产效率高的运输系统。大量采矿法的应用导致生产能力的显著提高,为适应矿石快速运输的要求,加拿大国际镍公司安大略分部于1983年开始研制自动运输汽车。最初的设想是用连续装载机与汽车配套,但为了把开发研究的工作量减到最少。而把汽车作为独立开发项目来研究。自动运输汽车课题包括方案的设想、初步设计和详细设计、加工制造、地表试验和井下应用。1988年完成了自动运输汽车的制造和试验的准备工作。接着,首先将汽车运往试验车道进行检验。试验检验已证明很成功,1989年决定将这台车交付小斯托比矿在2000水平使用。1990年这套系统正式投入使用,现在已在该矿全功能运转,日运矿石3000t。本文将介绍这项工程迄今所取得的成就。     

伊朗迪兹拱坝的再分析

本文对迪兹拱坝的静力和动力再分析结果进行了讨论。这座203.5m高的双曲拱坝,位于地震活跃的扎格罗斯山脉,是目前亚州最高的拱坝。该坝的特点之一是用周边缝把坝体与混凝土鞍座结构分隔开。采用滑移和无拉伸能力的曲线等参数接缝单元进行了非线性静力分析。还做了校正分析。由于库水位的变化,拱冠悬臂梁的径向变位是通过优化大体积的弹性模量进行校正的。最后,本文探讨了最大可信地震的非线性动力分析结果。使用破坏指数叙述了诱发地震的破环,该破坏指数可对不规则应力时程的不同类型进行比较。严密的分析表明,采用现代设计标准比用试载法得出较高的应力。