Optical system for measuring the profiles of super-smooth surfaces

The design of a common-path polarimetric interferometer system, developed primarily for measuring the profiles of ‘super-smooth’ surfaces, is described and measured comparisons with a mechanical stylus technique are discussed. The instrument has a sensitivity to changes in surface height of better than 0.1 nm and is capable of a lateral resolution of 1 μm with a helium-neon laser light source.     

梯度折射率分布极坐标测量方法和误差分析

研究了测量聚合物光纤径向折射率分布的相移干涉法,建立了数学模型,分析了测量误差的来源及影响,为能准确测得聚合物光纤的折射率分布提供了保证。     

Kinematic analysis of the multi-link five-point suspension system in point coordinates

In this paper, a numerical algorithm for the kinematic analysis of a multi-link five-point suspension system is presented. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. Geometric constraints are introduced to fix the relative positions between the points belonging to the same rigid body. Position, velocity and acceleration analyses are carried out. The presented formulation in terms of this system of coordinates is simple and involves only elementary mathematics. The results of the kinematic analysis are presented and discussed.     

镜面物体三维测量系统中两显示屏的平行正对校正

针对镜面物体三维测量系统中两显示屏无法精确平行正对的问题,提出了一种在镜面物体三维测量系统中通过软件产生变形条纹等效两显示屏精确平行正对的方法。该方法首先采用机器视觉技术标定两显示屏的外参。然后基于所标定的外参,利用软件编程产生等效两显示屏平行正对的变形条纹,变形条纹通过半透半反镜后所成的像在相机坐标系内呈现前后精确平行正对的关系。最后,利用对应两个显示屏上的变形条纹计算相应位置相位的差值,并通过均方根误差定量评定所提出的方法。实验结果表明,所提出的方法能将水平方向的均方根误差缩减为原来的24.21%,竖直方向的均方根误差缩减为原来的8.15%,从而提高三维测量系统的精度。     

四辊轧机平衡液压系统常见问题及其分析

轧机平衡液压系统是一个泵-阀-缸三位一体的比较典型的系统。系统运行的稳定与否,直接关系到整条轧机生产线能否安全、稳定、高效地运行。对该系统常出现的问题加以分析、总结,对以后的工作是大有裨益的。现将常见问题及其分析叙述如下: 一、系统无法建立起压力: 这种情况一般发生在试车阶段,其主要原因是:A)控制泵出口压力的电磁溢流阀的内部结构与系统有冲突或者其电磁铁的得、失电状态不正确。B)系统有短路的地方,检查各溢流阀是否有打开的,如果有,一定要关闭。C)重锤蓄能器下端的接近开关是否     

Friction and wear performance of MoDTC‐containing and ester‐containing lubricants over steel surfaces under reciprocating conditions

Lubricant oil can be regarded as a complex mixture of base oils and additives, each one with its specific functions and behaviour. In this paper, the interaction of a molybdenum dialkyldithiocarbamate (MoDTC)‐based additive and combinations of a polyalphaolefin and a synthetic ester is investigated. A reciprocating ball‐on‐disc configuration was used for tribological tests. The effect of MoDTC is seen as a sharp drop in the coefficient of friction. This friction reduction is affected by the base fluid: the effect is more intense and lasts longer when the ester content is decreased. The applied normal force also affects the MoDTC effect, which is not sustainable at higher loads. Copyright © 2014 John Wiley & Sons, Ltd.     

Eddy-current measuring system for analysis of alloy defects and weld seams

A measuring system based on an eddy-current transformer permits the detection of defects in plates of duralumin and aluminum–magnesium alloys.     

Using optical tweezers for measuring the interaction forces between human bone cells and implant surfaces: System design and force calibration

Optical tweezers were used to study the interaction and attachment of human bone cells to various types of medical implant materials. Ideally, the implant should facilitate cell attachment and promote migration of the progenitor cells in order to decrease the healing time. It is therefore of interest, in a controlled manner, to be able to monitor the cell adhesion process. Results from such studies would help foresee the clinical outcome of integrating medical implants. The interactions between two primary cell culture models, human gingival fibroblasts and bone forming human osteoblast cells, and three different implant materials, glass, titanium, and hydroxyapatite, were studied. A novel type of optical tweezers, which has a newly designed quadrant detector and a powerful 3 W laser was constructed and force calibrated using two different methods: one method in which the stiffness of the optical trap was obtained by monitoring the phase lag between the trap and the moved object when imposing a forced oscillation on the trapped object and another method in which the maximum trapping force was derived from the critical velocity at which the object escapes the trap. Polystyrene beads as well as cells were utilized for the calibrations. This is the first time that cells have been used directly for these types of force calibrations and, hence, direct measurements of forces exerted on cells can be performed, thus avoiding the difficulties often encountered when translating the results obtained from cell measurements to the calibrations obtained with reference materials. This more straightforward approach represents an advantage in comparison to established methods.     

对高校学生管理信息系统功能的描述与分析

随着Internet的迅猛发展,当今社会已进入网络时代,利用网络技术提高学生管理水平,对高校的学生日常管理工作有着广泛而深远意义.为此,采用现代计算机技术研究实现基于B/S模式的学生管理信息系统相关功能是本文研究的重点.从宏观角度阐述了开发高校学生管理信息系统的相关条件和系统的功能描述与分析,为开发能使学生管理工作规范化,系统化,程序化的高校学生管理信息系统提供可行性操作的研究.     

滚动轴承系统的寿命与可靠性

分析滚动轴承系统的寿命与可靠性之间的关系,对滚动轴承系统进行了可靠度的分配;对影响滚动轴承额定寿命的各因素进行讨论,并对滚动轴承额定寿命进行修正。     

闭环伺服系统的数学建模和性能分析

在数控机床中,伺服系统是数控机床装置和机床的中间连接环节,是数控系统的重要组成部分。伺服系统接受来自伺服控制器的进给脉冲,经变换和放大转换为机床工作台的位移,使工作台跟随指令脉冲移动。讨论了闭环伺服数控系统的数学模型,对闭环伺服系统的动态、静态性能进行了详细的分析,该研究结果为提高数控加工的控制精度提供了理论基础。     

影响切削工件表面质量的因素分析及要因的检测系统设计

采用因果分析图等质量分析工具分析了影响切削加工工件表面质量的原因,并找出了影响表面粗糙度的主要因素是切削力、切削温度和机械设备振动.针对切削力和切削温度影响因素,将薄膜热电偶技术引入切削温度检测,设计了一套切削力和切削温度的完整检测系统.试验表明,该检测系统人机交互作用强,操作简单,使用方便.     

汽车半轴楔横轧机辊系动态特性分析

应用ANSYS有限元动力学分析模块,求出汽车半轴楔横轧机辊系在现有边界条件下的固有频率和振型,分析辊系在不同中心距和不同约束下固有频率和振型的变化规律,研究结果为进一步优化该轧机设计,提高汽车半轴精度,实现汽车半轴高效化生产提供了理论基础.     

基于LabVIEW的滚动轴承非平稳过程监测诊断及性能评估系统的开发

以LabVIEW软件为开发平台,建立滚动轴承非平稳过程故障诊断及性能评估系统,完成系统硬件和软件的设计。系统采用NI9234数据采集卡,针对变工况下滚动轴承振动和瞬时角速度信号进行采集和分析。该系统集成了多通道数据采集、试验台控制、数据库存储以及基于该文研究算法的测试分析等模块。     

Integration of industrial photogrammetry and neuro-fuzzy system for measuring and modeling deformation of industrial product surfaces under external forces

Deformation of surfaces under external loadings greatly is function of physical laws. But according to the impossibility of identifying all effective factors and modeling their interactions parametrically, analytical methods do not provide good performance generally. So, it is necessary to apply practical methods by carrying out field tests and measuring deformations directly. To achieve this purpose it is required to integrate capabilities of an accurate measurement technique and a flexible modeling method. The capabilities such as: high accuracy and speed in measuring 3D coordinates of desired points, ability to perform measurement in a continuous space and no need to contact with the surface of objects at the time of measurement make close range photogrammetry a reliable tool for measuring geometric parameters of an object before and after deformation. The ability to measure geometric parameters of an object before and after deformation in one hand and following the deformation from physical laws on the other hand make neuro-fuzzy system the first choice for modeling the deformation of objects using outputs of close range photogrammetry.In this paper, a new method has been presented for measuring and modeling deformation of industrial product surfaces under external forces using close range photogrammetry (as an image-based measurement tool) and neuro-fuzzy network (as a behavior modeling tool).     

The use of the Zebris motion analysis system for measuring cervical spine movements in vivo

The cervical spine exhibits the greatest range of motion among the spinal segments due to the complex interaction of its triplanar components of movement. As a result, measurement of movements of the cervical spine and of the various orthoses used in cervical spine injuries has proved difficult with no one method proving satisfactory. This paper uses the Zebris ultrasonic three-dimensional motion analysis system to measure flexion, extension, range of lateral bending, and range of axial rotation in five similar male and five similar female subjects with no history of neck injuries. The subjects were tested unrestrained and in soft and hard collars, as well as in Philadelphia, Miami J, and Minerva orthoses. Results show that the Minerva is the most stable construct for restriction of movement in all planes in both groups. Looking at these results allows ranking of the measured orthoses in order of their three-dimensional stability. Furthermore, by presenting reproducible data incorporating the composite triplanar movements of the cervical spine, thus allowing comparative analysis of the studied orthoses, they propose the Zebris as a reliable, repeatable, and safe method of measurement of cervical spine motion with low intersubject variability.     

漳泽发电分公司煤量计量系统问题分析

分析了山西漳泽发电分公司所使用的皮带秤煤量计量系统在应用中发现的问题,并进行了原因分析,提出了处理方法。     

低温制冷系统两级喷射器设计与性能分析

本文提出了一种用于渔船低温制冷系统的两级喷射器,并对其进行了优化设计和性能分析。为达到最大引射性能,提出了基于流场参数匹配的两级喷射器优化设计方法,使用计算流体力学仿真软件对两级喷射器进行了建模和参数优化。此外,采用了水冷式冷凝器来减小冷凝器与蒸发器之间的压差,从而获得了更高的引射比。研究结果表明,所设计的两级喷射器可使蒸发温度低至248.15 K,第一级和第二级喷射器最优面积比分别为11.8和6.5。中间压力在253～324 kPa之间,引射比先增加后减小,在中间压力为304 kPa时达到最大值0.096,此时系统能效比达到0.074。可以认为,采用优化设计的两级喷射器和水冷式冷凝器,利用渔船余热驱动的低温制冷系统具有较好的节能效果。     

A new fuzzy network data envelopment analysis model for measuring the performance of agility in supply chains

Data envelopment analysis (DEA) is a linear programming method for assessing the efficiency and productivity of organizational units called decision-making units (DMUs). We propose a new network DEA (NDEA) model for measuring the performance of agility in supply chains. The uncertainty of the input and output data is modeled with linguistic terms parameterized with fuzzy sets. The proposed fuzzy NDEA model is linear and independent of the α-cut variables. The linear feature allows for a quick identification of the global optimum solution and the α-cut independency feature allows for a significant reduction in the computational efforts. We show that our model always generate solutions within a bounded feasible region. Our model also eliminates the potential for conflict by producing unique interval efficiency scores for each DMU. The proposed model is used to measure the performance of agility in a real-life case study in the dairy industry.     

Review of non-destructive measuring methods for the assessment of surface integrity: a survey of new measuring methods for coatings, layered structures and processed surfaces

Even though the near-surface areas of precisely manufactured parts represent only a few percent of the workpiece’s material volume, they influence its functional behaviour, quality and lifetime significantly. Therefore, sensors and measuring principles able to detect material changes, damage and process influences in the near-edge zone are of increasing importance. However, they have to meet industrial purposes concerning accuracy, measuring time, robustness and costs. In addition, they should work non-destructively and should offer the capability for integration in a production line.