压缩机厂房桥式起重机选型浅析

从工作环境、起升高度、额定起重量、工作级别、运行速度、跨度等方面论述了桥式起重机选型的国家标准、行业标准和运行参数;从起重机行程、操作方式和导电方式论述了桥式起重机的吊装方式以及吊装操作注意事项。     

Extracting the optimal dimensionality for local tensor discriminant analysis

Supervised dimensionality reduction with tensor representation has attracted great interest in recent years. It has been successfully applied to problems with tensor data, such as image and video recognition tasks. However, in the tensor-based methods, how to select the suitable dimensions is a very important problem. Since the number of possible dimension combinations exponentially increases with respect to the order of tensor, manually selecting the suitable dimensions becomes an impossible task in the case of high-order tensor. In this paper, we aim at solving this important problem and propose an algorithm to extract the optimal dimensionality for local tensor discriminant analysis. Experimental results on a toy example and real-world data validate the effectiveness of the proposed method.     

A computer program for internal conversion coefficients and particle parameters

Title of program: CATAR Catalogue number: ABGP Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland (see application form in this issue) Computer: UNIVAC 1108; Installation: Sandoz A.G., Basel, Switzerland Operating system: EXEC 8 Programming language used: FORTRAN IV High speed store required: 26K words No. of bits in a word: 36 Overlay structure: None Number of magnetic tapes required: None Other peripherals used: Card reader, line printer Number of cards in combined program and test deck: 3136 Card punching code: BCD     

基于模极大值小波域和TLS-ESPRIT的振荡瞬态识别方法

对于电能质量扰动检测和定位中振荡瞬态的检测、识别,目前普遍采用的是时频特征矢量提取和智能模式识别方法,此类方法无法准确提取电能质量振荡瞬态信号不同频率分量的组成。结合模极大值小波域和总体最小二乘法旋转不变技术的信号参数估计(total least squares-estimation of signal parameters via rotational invariance techniques,TLS-ESPRIT)可以很好地实现振荡信号的检测与识别。对于输入信号,首先采用模极大值小波域检测振荡发生的起始时刻和终止时刻,然后利用振荡时间间隔内的信号建立观测空间矩阵,通过奇异值分解和总体最小二乘法实现特征值截尾,将采样信号观测空间分解为信号子空间和噪声子空间,得到振荡信号每个构成频率分量的相应参数。仿真结果证实了所提出方法的可行性。     

整体式空间3自由度精密定位平台的优化设计与试验

根据柔顺薄板的弹性变形原理,设计一种整体式空间三自由度柔顺并联微动平台.分析该平台的输入耦合特性,对三种输入耦合形式对定位精度的影响进行讨论.基于有限元法,给出平台的刚度模型,对平台的结构尺寸进行优化设计,并通过ANSYS仿真分析验证优化结果的正确性.在此基础上进一步建立平台的位置正解和位置逆解方程,对平台的定位精度进行试验研究,提出一种基于理论分析模型的试验修正方法,该方法能有效提高平台的定位精度,研究表明该平台具有亚微米级的定位精度.     

自动送粉激光熔覆装置及工艺研究

研制了一种工作稳定性好、粉末流量连续可调的自动送粉装置。经A_3钢表面激光熔覆WF-150不锈钢合金粉末的研究表明,所获得的激光熔覆层均匀连续、无宏观气孔和裂纹,粉末利用率高达94％。     

机组初参数的热经济性模型研究及其应用

以汽轮机功率方程为基础,应用偏微分理论,根据汽轮机变工况的基本原理以及各参数之间的变化关系,经过严格的数学推导,得到了主蒸汽参数变化对机组热经济性影响的数学计算模型。此外,还以N600-16.7/537/537-I型汽轮机的运行数据为例,对模型进行验证。计算实例表明:该模型具有计算结果准确、使用方便、通用性强等特点,适用于工程实际应用,对机组性能监测和优化运行有重要意义。     

Research on relations between failure heights of overburden strata and ~] / mining face parameters and forecasting method

The commercial FEM software ANSYS was used to analyze the failure characteristics of overburden strata under the conditions of different lengths of mining faces. It was shown that the parameters of mining faces, especially the length was the important factor to the failure heights and shapes of overburden strata. Fuzzy mathematics and statistical methods were used to analyze the forecasting method of the failure height of overburden strata influenced by the parameters of mining face based on the measured data under the conditions of fully-mechanized mining of general hardness cover rocks. On the basis of these analyses, a new forecasting formula was gotten. The forecasting result conforms to the in situ measured value. The result has a very important application value in safe and high-efficient mining, and has a very important advancing function to theoretical studies.     

横向各向同性介质Thomsen近似公式的适用范围

Thomsen为横向各向同性（TI）介质提出的各向异性参数和线性近似公式被广泛采用,但目前对Thomsen近似公式的适用范围的认识仍很模糊。针对这一问题,研究了TI介质P波和SV波Thomsen近似公式最大相对误差随各向异性参数变化的特征以及近似公式的适用范围。研究结果表明,波速比α0/β0=1．5时,在-0．12≤ε≤0.16且-0.16≤δ≤0.24,或｜ε-δ｜〈0.17（ε和δ为正）时,P波相速度近似公式的最大相对误差不超过l％,随着了0／0的增大,适用范围略有扩大。SV波近似公式的精度比P波要低一些,在｜ε｜≤0.1且｜δ｜≤0.14,或｜ε-δ｜〈O．02（ε和占为正）时,SV波相速度平方线性近似公式的最大相对误差不超过1％,随着α0/β0的增大,适用伪范围明显缩小。总体来说,P波近似公式适用范围较大,对一些中等强度的各向异性也适用;SV波近似公式尤其是群速度近似公式适用范围很小,必要时需要使用高阶近似或者精确解。     

Optimal robot positioning using task-dependent and direction-selective performance indexes: General definitions and application to a parallel robot

Performance evaluation is an important issue for optimal robot positioning within workcells. Performance indexes can provide essential contributions to such an evaluation, in particular if they can account for the specific task with respect to which the optimization is carried out.