回转轴运动精度的干涉测量与误差补偿分析

采用激光干涉仪检测混联数控机床回转轴的运动精度,达到对其综合评价的目的,为机床的运动精度误差补偿做准备.对雷尼绍激光干涉仪的结构和角度测量原理进行了详细探讨,分析了干涉仪在回转轴运动精度测量中的主要影响因素和误差诱因;作出了角度测量中正弦近似误差特性曲线,并提出了该测量误差的数学模型;讨论了激光波长补偿的机理,提出了一种通用、简便易行的回转轴角位移精度检测方法.     

浸没式交换机液冷技术仿真与实验

交换机作为通讯传输技术的核心设备,内部芯片产生的热流密度越来越高,提高其散热效率是数据中心稳定运行的前提.本文对应用于交换机散热的新型浸没式液冷技术进行仿真与实验研究,通过高功率交换机的液冷散热仿真、浸没式液冷的散热效率实验对应用效果进行了分析和评估.结果表明:基于元件模型散热仿真分析的模型修正方法提高了温度预测的准确...     

Selecting the optimal mining method with extended multi-objective optimization by ratio analysis plus the full multiplicative form (MULTIMOORA) approach

Neural Computing and Applications - Mining method selection (MMS) is one of the core contents in mining design. As the influencing factors of MMS are in general of ambiguity or uncertainty, MMS can...     

Keggin结构的钨钴杂多酸盐的合成与表征

由Ｎａ２ＷＯ４·２Ｈ２Ｏ和Ｃｏ（ＮＯ３）２·６Ｈ２Ｏ在不同条件下合成了两种钨钴杂多酸盐，并对它们的结构和性质进行了表征。     

Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate

Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, X-ray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite (Cu) and pyrite (S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate (AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology (RSM), the interaction between AH, pulp pH and iso-butyl ethionine (Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t^-1 involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing. The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings.     

不同小试样测量蠕变性能的比较研究

小试样蠕变试验技术,在服役构件力学性能测试中得到了广泛的发展与应用。目前已有小尺寸单轴试验、小冲杆试验、剪切冲压试验、压痕试验、三点弯试验、悬臂梁试验、固支直杆弯曲试验、圆环试验和双杆试样等方法。基于上述小试样方法,重点从试样尺寸、应力状态、关联式类型、蠕变性能、变形测量和影响因素等方面,全面地综述不同小试样测量材料蠕变性能的方法和结果的异同。通过对比发现,不同类型试样所得蠕变曲线差异较大。小冲杆试样的数据转换过程较为复杂,试验过程中影响因素较多。悬臂梁试样和圆环试样的等效标距较大,变形测量误差小。三点弯、悬臂梁和圆环试样,蠕变试验过程中存在大变形效应,可采用临界载荷法预先控制试验载荷范围。固支直杆弯曲试样方法对摩擦的敏感性较低,可获得较为准确的断裂数据。所得结论为选择合适的小试样方法测试材料的蠕变性能提供理论指导和依据。     

粗糙集理论在多指标综合评价中的应用研究

对粗糙集理论在多指标综合评价中的应用进行研究,分析如何利用粗糙集进行权重确定,以及如何结合粗糙集与神经网络进行综合评价。提出基于粗糙集的距离综合评价方法,并用算例验证其有效性。     

基于多智能代理的机械产品创新设计支持系统研究

针对知识供应对现代机械产品创新设计的重要性，对创新设计所需的各种知识源及知识表示方式进行了研究，提出了基于异地协同设计的创新设计知识供应链，并探讨了一个可集成各类分布，异构知识的基于多智能代理的创新设计支持系统的功能，结构及其实现方式。     

幂律流体的二维层流自由射流

应用层流边界层方程,导出幂律流体二维层流自由射流的常微分方程,对该微分方程求数值解。结果表明,在相同的x处,n>1的流体的最大射流速度较n=1时增加,而射流宽度减小,n<1时则相反;并且,n值偏离1愈远,这种增加或减小愈甚。计算表明,射流宽度与x~(2/3n)成正比。