起重机吊钩拖动绕线电动机他励双高调速系统

本文提出励磁电流可自动控制的他励式双高调速系统设计方案。系统在提升特别是在下放重物时，具有较硬的机械性；在负载１０－１００％的变化范围内，可实现最大偏差Δｎｍａｘ／ｎｍｉｎ１００％≤１０％，调速范围Ｄ≥１０；在满载运行条件下，可节约电能８０％以上。     

A feasibility study of a direct-mapping parallel processing method to solve linear equations in load-flow calculation

With the growing size and complexity of power systems, system analysis—such as transients calculation—takes much time. Hence, fast calculation methods are required. Although parallel processing is a hopeful method, there have been difficulties in the parallel solution of linear equations which appear in power-flow calculations by the Newton-Raphson method. This paper aims at the fast calculation of the power-flow problem by means of parallel processing. In order to improve the suitability to the parallel solution of the differential equation in transients calculation, we assume the use of a direct-mapping parallel processing machine to map directly the network of a power system onto a network of processors. Under this assumption, we propose a new parallel-processing-oriented method in which the linear equation is solved by linear iterations between nodes with Aitken acceleration. We simulate the method on three model power systems and compare this Parallel Iterative Method (PIN) with a Parallel Direct Method (PDM) which uses the banded matrix according to the number of operations required. As a result, we can expect that PIM may solve linear equations faster than PDM with m processors, although the PIM might be inferior to the PDM with m × m processors, where m denotes the half-band width of the banded matrix.     

Li2O在保护渣中的作用

采用在不同玻璃性的两种基渣中加入Ｌｉ２Ｏ为研究Ｌｉ２Ｏ对保护渣粘度，熔化温度及玻璃性能的影响，并对Ｌｉ２Ｏ改善保护渣玻璃性的机理进行了探讨，提出了寻找高速连铸保护渣中Ｌｉ２Ｏ的代用物的一种方法。     

Ti,N,Mg对M2高速钢凝固组织和硬度的影响

为了改善Ｍ２高速钢共晶碳化物的分布，本文利用小凝固试样变质的方法研究了Ｔｉ，Ｎ和Ｍｇ对Ｍ２高速钢凝固组织和硬度的影响。试验结果表明，加入Ｔｉ或Ｔｉ－Ｎ后，共晶碳化物形态和分布有很大改善，而加入Ｔｉ－Ｎ后对凝固组织有轻微的细化作用，但只添加Ｔｉ不补碳时，钢的淬火硬度和回火硬度均下降；加入适量的Ｍｇ可以使片状的Ｍ２Ｃ型共晶碳化物转为鱼骨状的Ｍ６Ｃ型共晶碳化物，使其分布有所改善，Ｔｉ和Ｍｇ复合加入可以明     

On the hollowness ratio effect on the dynamics of a spinning Rayleigh beam

The analytical solutions of a spinning Rayleigh beam with rotatory moment inertia and gyroscopic effect are presented in this paper. The critical speeds can be written analytically in a function of the length-to-radius ratio (l) defined by the beam's length over its outer radius and the hollowness ratio (α) defined by the hollow area over the total area of the cross section. The sensitivity analyses show that the critical speed is decreasing with l, but increasing with α. Moreover, α is more sensitive to the critical speeds. The design of a spinning beam should therefore be emphasized more on the hollowness factor. Contrary to common belief, only finite critical speeds exist and the number is independent of the boundary conditions. It increases monotonically with l, but decreases with α. The steady state unbalanced response can therefore be expressed analytically by the finite precessional modes and the corresponding generalized coordinates.     

有机盐聚合醇氯化钾钻井液的应用

霍尔果斯背斜构造极其复杂,内应力极高,地层倾角大,断层、破碎带多,并存在高低压互层;安集海河组的灰绿色软泥岩水化严重并具有粘弹塑性.该区块重点探井霍003井三开、四开井段选用有机盐聚合醇氯化钾钻井液,同时为保证钻井液在高密度下（2.55 g/cm^3）具有好的流变性,使用活化铁矿粉、活化重晶石加重.应用结果表明,由于采用了强抑制和多元封堵的措施,该钻井液具有良好的流变性和较强的携带能力,钻进中曾携带出重2.8 kg和5.1kg的大掉块;滤失量低,泥饼质量好,封堵能力强,造壁能力强,减轻了井下阻卡程度;有良好的储层保护能力;在室内研究的基础上,经过现场合理使用和维护钻井液,霍003井提高了机械钻速,缩短了钻井周期,井身质量优于邻井.指出在高密度下,未选出适合有机盐聚合醇氯化钾钻井液的稀释剂,钻井液流动性较差.     

Comparison of mass transfer efficiency in horizontal rotating packed beds and rotating biological contactors

In this study, the mass transfer efficiencies of a novel horizontal rotating packed (h‐RPB) bed and the conventional disc‐type rotating biological contactor (RBC) were studied at four speeds and seven submergences. Pall rings of two different sizes (25, 38 mm), superintalox saddles and a wiremesh spiral bundle were used as packings in the h‐RPB. Volumetric gas–liquid mass transfer coefficients were determined by unsteady state absorption of atmospheric oxygen in de‐aerated water. Power consumption per unit liquid volume has been found for all geometries tested. The oxygen transfer efficiency values for the h‐RPB were found to be 2–5 kg kWh^?1 and for the disc RBC were found to be 1–2 kg kWh^?1. The performance of the h‐RPB was also compared with other gas–liquid contactors such as surface aerators. The study proves that the h‐RPB is a energy efficient alternative to conventional contactors. Copyright © 2005 Society of Chemical Industry     

Centrifugal Casting of High Speed Steel/Nodular Cast Iron Compound Roll Collar

Ｈｉｇｈ ｓｐｅｅｄｓｔｅｅｌ (ＨＳＳ) ,ｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙｅｘ ｃｅｌｌｅｎｔｈａｒｄｎｅｓｓ ,ｗｅａｒｒｅｓｉｓｔａｎｃｅ ,ａｎｄ ｇｏｏｄｒｅｄｈａｒｄｎｅｓｓ .Ｒｅｃｅｎｔｌｙ ,ＨＳＳｉｓａｐｐｌｉｅｄｔｏｍａｎｕｆａｃｔｕｒｅｈｏｔｒｏｌｌｉｎｇｒｏｌｌｓｔｏｐｒｏｄｕｃｅｓｔｒｉｐｓｏｆｇｏｏｄｓｈａｐｅａｎｄｓｍａｌｌｃｒｏｗｎｗｉｔｈｅｘｔｅｎｄｅｄｒｏｌｌｓｅｒｖｉｃｅｌｉｆｅ[1,2 ] .ＴｈｅＨＳＳｉｓａｐｐｌｉｅｄｔｏｍａｎｕｆａｃｔｕｒｅｒｏｌｌｃｏｌｌａｒｆｏｒ…     

露天矿山牙轮钻机主参数确定探讨

通过对牙轮钻、轴压、钻头速度、排碴风量、排碴风压的论述得出了如何调定牙轮钻的参数，为以后我矿牙轮钻在生产中获取最大经济效益积累了有益的资料。     

Necessary optimality conditions in a nonsmooth control problem with variable structure

An optimal control problem with nonsmooth performance criterion described by a system of ordinary differential equations is considered. Necessary first-order optimality conditions are obtained.