Effects of circumferential pick spacing on boom type roadheader cutting head performance

Effects of equal and unequal circumferential pick spacing on the performance of boom type roadheaders having cylindrical cutting heads are investigated. For this purpose, two experimental cutting heads with equal and unequal circumferential spacing are designed and manufactured. The cutting head with unequal circumferential spacing is specifically designed to prevent tool-holder overlap at the nose section. Manufacturing difficulties associated with equal circumferential pick spacing due to tool-holder overlap are discussed with solid modeling and practical applications. The heads are tested at Park Cayirhan Coal Mine in Turkey and their cutting performances are analysed. Although better cutting performance for equal circumferential spacing are predicted by force–balance analysis, in situ measurements of instantaneous (net) traversing speed and cutting rate, pick consumption rate and machine vibration show that no significant difference exists between the performances of the two cutting heads.     

基于模糊神经网络对经济的聚类分析

在现实生活中具有同等人力资本的劳动者在不同的生产力环境下的经济贡献率是不同的 ,有时甚至不可比较的。利用人工神经网络 (SOM网络 ) ,通过 Matlab语言编程 ,根据技术进步增长率对整个经济进行模式分类。分类的结果是大致把 2 9个省市分为 6个类 ,反映了各地区的经济与技术进步增长率情况     

DGPS在可控震源施工中的应用

在可控震源施工中，采用DGPS(差分全球卫星定位系统)实施实时点位监控，对保证施工质量、提高生产效率起着积极的作用。本文主要介绍PELTON ADVANCE Ⅲ GPS系统的安装和使用情况。     

Multidimensional Personality Questionnaire profiles of veterans with traumatic combat exposure: Externalizing and internalizing subtypes.

This study used the Multidimensional Personality Questionnaire (MPQ; A. Tellegen, in press) to identify personality-based subtypes of posttraumatic response. Cluster analyses of MPQs completed by combat veterans revealed subgroups that differed on measures relating to the externalization versus internalization of distress. The MPQ profile of the externalizing cluster was defined by low Constraint and Harmavoidance coupled with high Alienation and Aggression. Individuals in this cluster also had histories of delinquency and high rates of substance-related disorder. In comparison, the MPQ profile of the internalizing cluster was characterized by lower Positive Emotionality, Alienation, and Aggression and higher Constraint, and individuals in this cluster showed high rates of depressive disorder. These findings suggest that dispositions toward externalizing versus internalizing psychopathology may account for heterogeneity in the expression of posttraumatic responses, including patterns of comorbidity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

聚合物包覆热分解法制备纳米氧化锌的工艺研究

采用聚合物包覆热分解法化学工艺制备了纳米氧化锌，对其工艺进行系统的比较研究，对所得粉体进行XRD与SEM表征。发现利用该工艺所得粉体为六方晶系纤锌矿结构（空间群为P63mc）的纳米氧化锌。该方法制备的氧化锌衍射峰尖锐，表明此种方法合成的氧化锌结晶程度高。所得的氧化锌粉体XRD图谱中没有杂质衍射峰，说明产物纯度都很高。产品SEM表征结果显示了此工艺产物在形貌方面的高度一致性——为菊花状氧化锌纳米杆团簇，对产物形貌形成的原因做了探讨。     

Failures of retrieval and comparison constrain change detection in natural scenes.

In a change detection paradigm, a target object in a natural scene either rotated in depth, was replaced by another object token, or remained the same. Change detection performance was reliably higher when a target postcue allowed participants to restrict retrieval and comparison processes to the target object (Experiment 1). Change detection performance remained excellent when the target object was not attended at change (Experiment 2) and when a concurrent verbal working memory load minimized the possibility of verbal encoding. (Experiment 3). Together, these data demonstrate that visual representations accumulate in memory from attended objects as the eyes and attention are oriented within a scene and that change blindness derives, at least in part, from retrieval and comparison failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

旋转控制头胶芯失效形式分析

在欠平衡钻井过程中，胶芯是旋转控制头核心密封元件，通过对Williams 7100型旋转控制头胶芯失效形式进行分析，并提出了相应的对策，旨在推动胶芯的国产化进程。     

投产气井的模糊聚类分析

根据过去对投产气井分类问题的研究与应用效果，提出采用模糊数学的模糊聚类分析方法来研究投产气井的分类问题，通过编制计算机程序对陕甘宁中部气田１６口投产气井应用表明，分类结果更加合理。     

以应力分析为基础的汽包封头强度计算

本文介绍应力分析设计法的原理，通过有限元计算得到汽包封头的温度场、应力场，并以应力分析为基础对汽包封头强度作了校核。     

太钢3号卷取机TDC控制系统开发与应用

太钢热连轧厂3号卷取机改造前所采用的美国西屋公司WDPF控制系统已不能满足目前生产和质量的要求，进而应用西门子公司的TDC控制系统对其进行了改造。该项目的设计、编程、调试由太钢自行完成，改造中采用了带钢头部张力优化控制、夹送辊张力控制、卷取机平滑曲线减张控制、卸卷小车横移极限升降极限模拟控制等多项新技术。其改造后产品产量、综合成卷率和卷形良好率均明显提高。