超导体的超导电性和反铁磁性共存的研究

在二维空穴掺杂t-t′-J-U模型和重整化平均场理论的框架下,用Gutzwiller方法研究了Gossamer超导体的超导电性和反铁磁性的共存,探讨了电子次近邻跃迁对共存的影响,发现在掺杂浓度δ≤0.1的欠掺杂区反铁磁序和超导序共存。随着电子次近邻跃迁的增大,反铁磁序得到增强,超导序参数在欠掺杂区域受到抑制,在过掺杂区明显地得到增强,导致反铁磁序和超导序共存区域变大。超导序和反铁磁序共存的状态比纯粹的超导态能量低,共存状态更稳定。     

Evolution of methods of assessing the accuracy of metal-cutting machines

The evolution of concepts of accuracy and attainable machining accuracy are considered. The physical aspects of accuracy are discussed. The changes in the level of precision since 1800 are outlined, with predictions of what is attainable in the future. The energy barrier to accuracy is analyzed for various cutting technologies.     

Development of sclerometric method of studying activation of parameters of damage and fracture of friction deformable surfaces

The article presents a brief review of the wear models based on the kinetic thermofluctuation approach. The materials were developed using SamGTU sclerometric programming software and a set of instruments developed at Samara Engineering University for assessing the parameters of kinetic thermoactivation for surface fracture deformed by friction. The first obtained results of assessments and the estimated prediction of wear resistance exemplified by tribocouple of the aircraft chassis are presented.     

轮胎单个横沟泵吸噪声计算方法研究

以205/50R16子午线轮胎为对象,建立具有横向花纹沟槽的有限元法分析模型,利用Abaqus/Explicit进行瞬态滚动分析,得到滚动轮胎单个横沟的体积变化。将其导入Fluent中,利用计算流体力学方法对单个横沟泵吸效益流场进行分析,并结合Lighthill声学类比理论预测横向沟槽的噪声,同时基于涡声理论验证流场与噪声之间的关系。结果表明,单个横沟泵吸噪声第一峰值集中在0.8～2.0 kHz附近,仿真数据与试验结果在趋势上具有一致性;且噪声的声压峰值出现在泵吸状态发生转变的时间段;在时域中的3个噪声峰值出现涡量变化较大的时间段,已确定噪声的变化可由涡量来反映。     

双丝杠驱动机构同步分析

介绍了双丝杠驱动机构工作原理,论述了双丝杠运动产生不同步的原因以及如何判定与解决同步问题。     

基于梁弯曲理论的聚焦镜压弯技术研究

分析了通过压弯技术实现聚焦镜的基本原理,该技术以梁的弹性弯曲变形理论为基础,通过对基底施加力偶矩,获得各种聚焦镜。建立了柱面镜、超环面镜和椭圆柱面镜的压弯力学模型。利用有限元方法对超环面镜的压弯力学模型进行分析。     

Calculation of characteristics of discrete adhesive contact

The mathematical model of discrete contact between real engineering surfaces has been proposed. The model takes into account the adhesion between surfaces in contact. The analytical expressions for calculating the deformation of a contact and the real (physical) contact area have been obtained. The dimension-less criterion for estimating the influence of adhesive forces on the contact characteristics has been proposed. The effect of various factors on the above characteristics has been analyzed. It has been shown that, at the nanoscale level (asperities of nanoscale size), especially under low contact loads, the influence of adhesive forces is significant.     

异步电动机软启动器设计

异步电动机启动电流大，频繁启动易造成电机损坏，采用单片机控制的软启动器可实现电机的限流、限压。该异步电动机软启动器以单片机MSP430F149为核心，通过软件设计实现电机的启动和保护，具有电路结构简单、稳定性好的特点，尤其是具有极强的抗干扰能力，适合应用于工业环境下，应用前景广阔。     

伪装涂层附着力影响因素研究

测试了伪装网用伪装涂层的剥离强度,提出了一种考核伪装涂层附着力的方法。研究了涂层附着力的来源,涂层与底材之间相互作用的机理,介绍了常用的涂层附着力改进剂,阐述了它们改善涂层附着力的作用机理,合理使用涂层附着力改进剂可以显著提高涂层的附着力。     

浅析刀刃附着物——积屑瘤

介绍了刀刃附着物的分类,讨论了积屑瘤的成因、成长与脱落的全过程,分析了积屑瘤与切削条件的关系,以及在切削加工中的作用,提出了抑制积屑瘤产生的措施。     

偏置双曲柄滑块机构急回特性分析

分析偏置双曲柄滑块机构的急回运动特性,给出了机构的设计公式。分析结果表明该机构不仅有超急回运动的可能性,且具有可变急回运动特性,机构中各构件尺寸一定时,仅仅改变其相对安装位置,便可获得不同行程速比系数。     

射流泵最佳参数的确定方法

根据能量守恒原理得出了射流泵效率计算公式，再利用多元函数极值原理给出了射流泵最优参数方程，求解并给出了射流泵基本性能包络线和效率包络线，分析了摩擦损失系数和密度比对最优参数的影响，确定出最优化面积比值。理论计算结果表明：在等密度体系和Petrie给出的摩擦损失系数条件下，最优面积比为0．280，与文献[8]中给出的实验结果相近；摩擦损失系数是影响射流泵效率的主要因素，密度比对最优工作点有一定的影响；最优面积比只与摩擦损失系数有关，而与流体间的密度比无关。研究结果对工程应用具有指导意义。     

Wear of tribe-elements of video tape recorders

The helical scan magnetic recording equipment, like the video tape recorders (VTR), consist of many tribe-elements. The wear of these tribe-elements is an essential problem affecting the reliability of the equipment. The rotating magnetic head in high-speed rubbing with the magnetic tape needs a self-cleaning effect by mild wear. A simple trial of reducing the head wear often brings partial recession, friction polymer and brown stain. The summary of the current study of head wear is given by dividing it into the head factors, the tape factors, the system factors and the atmosphere factors. The computational analysis of head contour change caused by wear is compared with the experimental results. The outline of the tribology of motor, capstan and tape path in the VTR is introduced.     

雷达显控台的人性化设计

阐述了雷达显控台的人性化设计,结合工业设计中所包含的人机工程学原理及人体测量学的相关数据,对雷达显控台的造型设计和色彩搭配设计进行了详细的论述。     

AutoCAD二次开发在STAAD-Pro的后处理中的应用

介绍了利用VC 和AutoCAD二次开发工具ARX对Staad-Pro后处理数据图形化显示的开发过程。分别从处理后的数据中提取可视化所需数据,通过DWG图形直观地显示出指定平面钢结构的信息,同时数据报表的输出大大提高了数据分析的效率和数据提取的准确性。多线程技术的应用缩短了程序整体运行时间。     

Geometrical method of selection of features of diagnostic signals

The paper presents the method of selection of features of diagnostic signals relying on the geometry of observation space. The method presented here uses two criteria of ability to separate (isolate) classes of an object's state: the criterion of average scatters and the original criterion of number of prototypes of classes. The method can be successfully used for initial analysis of input data to a neural network dealing with recognition of patterns and classification of an object's state. It also possible to use the algorithm presented here for determining the prototypes of classes needed for creating the training set for the neural network.     

Development of Methods of Ultrasonic Nondestructive Testing of Welded Joints

The methods of ultrasonic nondestructive testing of welded joints used in Russia are reviewed. The ways of testing the reliability of the testing results are discussed.     

枸杞子提取物中多糖含量测定方法研究

采用苯酚-硫酸法衍生,紫外-可见分光光度法测定枸杞子提取物中枸杞子多糖含量。对样品制备及含量测定方法进行充分验证,最大吸收波长490nm,葡萄糖线性范围为2.65～13.3μg/mL,r=0.99939,平均回收率为101.32%,RSD为2.39%。所建立方法准确、可靠,可用于枸杞子提取物中多糖的含量测定。     

微机器人的研究现状与发展趋势

微机器人学包括微型机器人和微动机器人,微/纳米技术的迅速发展促进了微机器人技术的发展.微机器人在一些不便于人直接操作的狭窄环境(如管道)和微细作业技术中有广泛的应用,文中主要分析了微机器人特别是并联微动机器人的国内外研究现状,提出了目前微动机器人研究的不足及发展趋势.     

分光光度计比色装置的改进

对722型分光光度计的比色池作了改进。改进后的比色装置能有效简化操作过程,缩短比色时间,特别适用于在一次分析中样品较多的比色分析。装置造价低廉,材料容易获取,仅需对原设备做少量改装即可。该装置也适用于类似的比色仪器。本文对改进的比色装置作了详细介绍。