拉丝固体润滑剂的模糊综合评判

本文采用了模糊数学的方法,在大量试验的基础上,建立了拉丝固体润滑中的各种主要润滑因子的隶属函数,并对七种典型润滑剂进行了二级模糊综合评判。     

贮仓自振特性实验研究

通过对多层仓顶室柱承式贮仓的实验研究,得出了贮仓自振特性随贮料员、贮料状态(散体料、固结料)和激振力变化的基本规律。为进一步完善这类贮仓自振特性的计算提供了可靠的依据。     

稀疏脉冲和基于模型反演在王家岗沙四段砂岩油藏精细勘探中的应用

1998年11月,胜利油田王家岗地区的第一口发现井（WX119井）在埋深2500－3000m的沙河街组沙四段砂岩中发现了高产工业油气流,随后如何进一步确定含油砂体展布范围和空间厚度变化成为对油藏作进一步评价和开发的关键。在研究区仅有4口井的情况下,利用基于道的稀疏脉冲三维地震反演方法确定了含油砂体的分布范围及厚度变化,据此部署的3口评价井和1口探井都获得了高产工业油气流。根据与已知含油砂体的波阻抗特征的类比,对没有钻探的高阻抗区进行钻探以使含油气范围不断扩大。钻井数达30口,其中仅2口井失利。为了进一步搞清含油砂体分布范围,我们采用了基于地质模型的三维地震反演,对所钻遇的油层分布进行了预测,分析了失利井的原因,提供了新的钻探目标,并为开发井的部署提供了有利的地质依据。     

地学应用中的便携式微机多道能谱仪

便携式机多道能谱仪以笔记本式计算机的为核心,采用１２位逐次逼近型Ａ／Ｄ转换芯片,研制成软硬件相结合的２０４８道能谱仪,讨论了适用于地学的野外微机多道能谱仪的硬件电路和软件特点,以及在γ能谱测量和Ｘ荧光测量全谱分析中的初步应用情况,该仪器及其研制技术也适用于其他有关核潜测量研究。     

Topological design of freely vibrating continuum structures for maximum values of simple and multiple eigenfrequencies and frequency gaps

A frequent goal of the design of vibrating structures is to avoid resonance of the structure in a given interval for external excitation frequencies. This can be achieved by, e.g., maximizing the fundamental eigenfrequency, an eigenfrequency of higher order, or the gap between two consecutive eigenfrequencies of given order. This problem is often complicated by the fact that the eigenfrequencies in question may be multiple, and this is particularly the case in topology optimization. In the present paper, different approaches are considered and discussed for topology optimization involving simple and multiple eigenfrequencies of linearly elastic structures without damping. The mathematical formulations of these topology optimization problems and several illustrative results are presented. An erratum to this article can be found at     

Construction Control and Pile Body Tensile Stresses Distribution Pattern during Driving

In this paper, the pile body tensile stresses distribution pattern during driving is discussed, based on dynamic piling testing results of 13 driven piles attained by the laboratory and in situ tests. These tests indicate that the maximum driving tensile stresses occur in the upper portion of the pile, especially at the initial stages of driving the pile tip seated on soft soils or if the pile foundation is built on a soft foundation. After serious study, it can be concluded that the maximum driving tensile stress often occurs at (1/4)l (l stands for the length of pile) from pile top with its value accounts for 50% of the driving compressive stresses at the same cross section. This high driving tensile stress would lead to the occurrence of transverse cracks and even the breakage of the pile, which should claim the attention of the engineer. The tests also demonstrate that high driving tensile stresses often occur due to the usage of a conventional pile cap in the driving of a prestressed concrete (tubular) pile. To the contrary, the tensile stresses tend to diminish within the control tensile stresses (5?MPa) due to the usage of a new type of disk spring pile cap during driving. Moreover, this new pile cap can prevent driving deviation from alignment, ensure an even distribution of the hammer blow on pile top, and protect the integrity of the pile body.     

基于DCS 500控制的双机驱动同步控制系统

对双机同步调速控制的特点进行了理论分析,提出了双电动机柔性连接同步驱动的速度补偿、电流补偿方案.介绍了用此同步控制技术,利用ABB公司的DCS500进行矿井提升机双机驱动速度同步控制的实现方法和控制结果.结果表明,该系统运行稳定、可靠.     

径向基神经网络示波计时电位法同时测定铅和镉

将径向基神经网络用于Pb~(2 )和Cd~(2 )示波计时电位重叠切口的解析,建立了同时测定Pb~(2 )和Cd~(2 )的径向基神经网络示波计时电位分析新方法。实验表明:所建模型对训练集20个样本,预测结果相对标准偏差平均值仅为0．93%,而主成分回归模型预测结果为3．2%,偏最小二乘回归模型预测结果为3．0%。用本文方法预测的结果比主成分回归和偏最小二乘回归模型准确度高。     

一种智能变电站监控信息自动验收系统的研究

随着电力技术的发展,调度监控系统需要在智能变电站中采集大量的设备运行状态信息,导致信息接入验收的工作量非常大。现有的智能变电站监控信息自动验收系统只实现了从终端到主站的信号验收,无法实现整个信号的闭环实时传递。同时,变电站监控中频谱泄漏和栅栏效应会对采集的结果产生较大的影响。对此,基于IEC61850和多机多网并行校核理论,研究并开发了一套智能变电站监控信息的自动闭环验收系统,同时提出了一种基于全相位频谱矫正技术的高效变电站数据监测方法。依托某省电力公司的实际工程项目对提出的理论和方法进行了相关仿真和实验分析,验证了所提出方法的有效性和可行性。     

Design of Unskewed Interior Permanent Magnet Traction Motor with Asymmetric Flux Barriers and Shifted Magnets for Electric Vehicles

Abstract

Interior permanent magnet synchronous motors (IPMSMs) are commonly used in electric and hybrid electric vehicles. Nissan Leaf electric vehicle (EV) uses skewed-rotor IPMSM as a traction motor. This motor is considered as a benchmark in this work. Although, skewing improves the torque quality of the motor by reducing the torque ripple, it reduces the average torque and increases the motor manufacturing complexity and cost. This article proposes improvements to the benchmark motor torque quality without skewing. The proposed motor uses the same stator winding and rotor magnet topologies of the benchmark motor with the same geometric constraints and magnet volume. Modifications are applied to the placement of the magnets in the rotor and the shape of the flux barriers to achieve the performance requirements. The design procedure of the proposed unskewed design is illustrated. Moreover, the electromagnetic performance of the proposed design is investigated. The design shows competitive performance in terms of the average torque, torque ripple, cogging torque, and efficiency compared to the benchmark motor. The mechanical integrity of the design is also verified. The proposed design is found to be a suitable alternative to the benchmark traction motor with a reduced rotor weight and without skewing.