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。     

千分尺使用中产生测量误差的原因及对策

千分尺是机械工业中使用最广最重要的量具之一,它可以对零件的外径、球径、长度以及两平面的平行度等内容进行测量。因为它的设计符合阿贝原理,所以,测量精度很高。它的使用正确与否,将直接影响检验产品时的合格程度和影响企业经济效益的提高。而且也是衡量一名机械工人技术业务素质高低的重要标志。在机械加工和职工培训中,笔者经常发现不少工人在使用千分尺测量零件时,常有测量误差产生。本文将就测量误差产生的原因及对策予以探讨,以利改善测量方法,提高测量技术,减少原材料浪费,提高产品合格率。 (1)使用千分尺前,操作者应查看千分尺的检     

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     

提高玻璃退火窑辊道安装精度的工艺措施

浮法玻璃退火窑是现代浮法玻璃生产线三大热工设备之一。本文着重介绍退火窑辊道安装、测量的主要工艺技术措施。     

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

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