Experimental studies of focal mechanism based on the dynamic process of energy release

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Experimental Study on Electrostatically Actuated Micro-Gripper Based on Silica Process

The characteristics of a kind of comb-drive electrostatic actuated micro-gripper are tested. The test platform using a microscope-CCD-computer, the state information of the micro-gripper obtained by data acquisition and image processing, voltage-displacement characteristic curve is obtained and the mathematical equation is established. The analysis of the characteristic equation has shown the consistency and rationality of the theoretical design and the experimental results. The main factors that cause the difference between the theoretical design and the actual test performance are analyzed, and the design method and experimental results is obtained for the micro-gripper in the field of micro-assembly.

Research on the Application of Intelligence Teaching Mode of Superstar Platform in the Teaching of Experimental Design and Data Processing

Experimental Design and Data Processing is an important core professional basic course for food science majors.This course is theoretical and practical,and there are many formulas,abstract contents and difficult to understand,and there are some problems in the teaching process,such as students1 poor interest in learning,insufficient mastery of what they have learned,and inability to combine theory with practice organically.Through analyzing the existing problems,this paper puts forward some reform measures for the teaching mode of experimental design and data processing by using the intelligent teaching of Superstar platform.

Numerical and experimental analysis of quenching process for cam manufacturing

In order to obtain satisfactory mechanical properties for the cam used in high-power ship diesel engines, a new quenching technology was proposed by designing a two-stage quenching process with an alkaline bath as the quenching medium. To demonstrate the effectiveness of the proposed new quenching technology, both numerical analysis and experimental study were performed. The new quenching technology was analyzed using finite element method. The combined effects of the temperature, stress and microstructure fields were investigated considering nonlinear material properties. Finally, an experimental study was performed to verify the effectiveness of the proposed new quenching technology. The numerical results show that internal stress is affected by both thermal stress and transformation stress. In addition, the direction of the internal stress is changed several times due to thermal interaction and microstructure evolution during the quenching process. The experimental results show that the proposed new quenching technology significantly improves the mechanical properties and microstructures of the cam. The tensile strength, the impact resistance and the hardness value of the cam by the proposed new quenching technology are improved by 4.3%, 8.9% and 3.5% compared with those by the traditional quenching technology. Moreover, the residual stress and cam shape deformation are reduced by 40.0% and 48.9% respectively for the cam manufactured by the new quenching technology.

Dynamic experimental study on rock meso-cracks growth by digital image processing technique

A new meso-mechanical testing scheme based on SEM was developed to carry out the experiment of microfracturing process of rocks. The microfracturing process of the pre-crack marble sample on surrounding rock in the immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression was recorded by using the testing scheme. According to the stereology theory, the propagation and coalescent of cracks at meso-scale were quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, was obtained from binary images after segmentation. The failure mechanism of specimen under uniaxial compression with the quantitative information was studied from macro and microscopic point of view. The results show that the image of microfracturing process of the specimen can be observed and recorded digitally. During the damage of the specimen, the distribution of microcracks in the specimen is still subjected to exponential distribution with some microcracks concentrated in certain regions. Finally, the change law of the fractal dimension of the local element in marble sample under different external load conditions is obtained by means of the statistical calculation of the fractal dimension.

Experimental Study of Monitoring and Controlling of Composite Cure Process in Autoclave Featured with Fiber Optic Sensor

With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely and efficiently.In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.

金属空心球复合材料重力铸造工艺研究

基于对金属空心球复合材料的结构分析,采用金属型重力铸造法制备金属空心球复合材料。介绍了金属空心球复合材料金属型重力铸造工艺流程,并设计了一种成本低廉、简易成型、且能多次使用的金属型模具,且对金属空心球复合材料进行了实验试制及材料验证。结果表明,采用金属型重力铸造法能够制备出孔壁结构完整且孔洞随机分布的金属空心球复合材料,能实现空心球单一设计与梯度设计;金属空心球复合材料基体与空心球壁组织较为致密,且形成了厚度为25~30μm的界面层;金属空心球复合材料的应力-应变曲线具有明显的弹性阶段、塑性平台阶段和致密化阶段,且采用空心球梯度设计的金属空心球复合材料相较于空心球单一设计的金属空心球复合材料,其基本力学性能有明显的提升。最后,与传统的闭孔泡沫铝材料进行了对比分析,金属空心球复合材料整体稳定性更高,吸能效果更强。

基于正余弦函数设计位移运动算法的研究与实现

为实现机床加工运动过程中算法规划能输出连续的运动指令,提高位置控制精度,文章基于正余弦函数值周期连续变化的特性,设计出位移运动指令随时间连续变化的算法模型并进行公式推导。结合Matlab对算法的规划细节进行仿真分析,得到算法规划的控制指令平稳且连续,证明了算法模型建立与公式推导过程的正确性。选择机床加工PCB覆铜板运动过程为试验研究对象,使用激光干涉仪对机床加工实际位移距离进行测量,测得采用所设计的位移运动算法进行运动过程规划,位置控制精度能达到1.788μm,验证了位移运动算法的正确性。

矿物加工虚拟仿真实验教学建设及实践——以中南大学矿业学科为例

针对新时代矿业行业对专业人才的要求,以培养学生全周期工程思维和提高其工程胜任力为目标,采用虚拟仿真的教学手段,突破矿产资源加工过程中高温、高危、高成本等限制,解决传统教学无法开展全流程实验及生产极端工况操作等难题,将科研成果融入实验教学,有机融合数据库技术、虚拟仿真、专家系统、智能算法,让学生通过自主选题、自主探究学习、自主流程设计、自主设备搭建、自主调试运行,设计与资源特性相适应的工艺流程、生产设备及操作参数,实景体验工业生产过程异常工况,使其成为具有实干担当、开拓创新、国际视野和竞争力的矿业卓越人才。

Selection of Leading Industry in Anshun Experimental District Based on Analytic Hierarchy Process

Analytic Hierarchy Process is selected according to the selection method of leading industries by both domestic and foreign scholars. Leading industries which can accelerate the overall economic development of Anshun Experimental District is taken as the target layer; and market demand, efficiency standards and local conditions are taken as the criterion layers, so as to construct the select model of leading industry and to choose the leading industry in Anshun Experimental District. Result shows that the priority order of the leading industry selection in Anshun Experimental District is as follows: tourism > pharmacy > transportation > energy > food processing > characteristic agriculture > package and printing > automobile industry > mining > electric engineering.

合成孔径雷达高分辨率成像虚拟仿真实验平台设计

合成孔径雷达(synthetic aperture radar,SAR)系统组成复杂,搭载于飞机、卫星等运动平台上才可实现数据获取,难以开展基于SAR雷达实物的实验教学。为解决此问题,设计并搭建了SAR高分辨率成像虚拟仿真实验平台。该虚拟仿真实验平台将系统设计技术、实验设计技术、数据采集过程、信号处理技术、图像评估技术等SAR实验的完整流程进行了高展示度、高保真度、高交互性的计算机模拟。一方面,该虚拟仿真实验可以帮助学生理解SAR设计、工作和应用的流程,巩固相关课程基础知识,激发学习雷达信号处理知识的兴趣;另一方面,可以考查学生对相关知识的综合应用能力,增强学生解决实际问题的技能。该仿真平台已成功应用于虚拟仿真教学课程实践,教学效果良好,对培养新工科技术型人才具有重要意义。

牛马藤多糖的提取工艺优化及抗氧化活性研究

为明确牛马藤多糖的提取工艺条件及其抗氧化活性,为牛马藤多糖的开发利用提供参考。采用了苯酚-硫酸法测定牛马藤多糖的含量,通过单因素试验(以提取温度、液固比、提取时间、提取次数为参考因素),正交试验对牛马藤多糖的提取工艺进行优化,DPPH法和ABTS法测定牛马藤多糖的抗氧化活性。所优化的牛马藤多糖提取工艺稳定可行,提取率高,牛马藤多糖具有一定的抗氧化活性。

Effects of granulation process variables on the physical properties of dosage forms by combination of experimental design and principal component analysis

The current study was to understand how process variables of high shear wet granulations affect physical properties of granules and tablets. The knowledge gained was intended to be used for Quality-by-Design based process design and optimization. The variables were selected based on the risk assessment as impeller speed, liquid addition rate, and wet massing time. Formulation compositions were kept constant to minimize their influence on granules properties. Multiple linear regression models were built providing understanding of the impact of each variable on granule hardness, Carr’s index, tablet tensile strength, surface mean diameter of granules, and compression behavior. The experimental results showed that the impact of impeller speed was more dominant compared to wet massing time and water addition rate. The results also revealed that quality of granules and tablets could be optimized by adjusting specific process variables(impeller speed 1193 rpm, water spray rate 3.7 ml/min, and wet massing time 2.84 min). Overall desirability was 0.84 suggesting that the response values were closer to the target one. The SEM image of granules showed that spherical and smooth granules produced at higher impeller speed, whereas rough and irregular shape granules at lower speed. Moreover, multivariate data analysis demonstrated that impeller speed and massing time had strong correlation with the granule and tablet properties. In overall, the combined experimental design and principal component analysis approach allowed to better understand the correlation between process variables and granules and tablet attributes.

基于PLC和组态王的反应器实验平台设计

以反应器工业流程为基础,搭建了多参数的反应器实验平台。使用西门子S7-200系列PLC作为控制器,完成了控制程序开发与调试;使用Kingview组态软件完成了监控界面设计。该实验平台为PLC、过程控制以及组态王等相关课程提供了多个实验项目,加深了学生对专业课程的理解及融合运用,更好地提升了学生的综合性实验能力,还满足了学生学科竞赛的需求,有助于新工科的人才培养。

基于便携式粗糙度仪的表面轮廓测量实验平台设计

该文基于便携式粗糙度仪设计了一种用于采集工件表面轮廓数据的测量实验平台,并同步开发轮廓分析软件。该测量实验平台由三轴移动装置、夹具、轮廓数据采集装置(粗糙度仪)及计算机组成,可采集水平方向上0.3~16.0 mm、垂直方向上–200~200μm复杂表面的轮廓数据,用于微结构或非球面等面型的测量实验。基于MATLAB软件设计模块开发了轮廓数据处理及分析软件,与金相显微镜及泰勒霍普森轮廓仪所测量的轮廓数据结果对比,该测量实验平台的测量误差低于5%,证明该平台及测量方法的可靠性和准确性。

农业科研试验站建设实践与建议——以河北省农林科学院石家庄果树研究所科研试验站为例

文章回顾了河北省农林科学院石家庄果树研究所科研用地发展历程,介绍了河北省农林科学院石家庄果树研究所科研试验站建设历程和取得的成效,并从试验站建设要立足长远、要高标准、要科学规范、要实现多功能化等方面提出了加强农业科研试验站建设的建议,以期为农业科研院所科学管理科研用地,提高科研用地利用效率,加强农业试验站建设提供参考。

声发射定位技术在锚杆拉拔脱黏实验教学中的应用

该文针对锚杆拉拔脱黏实验教学存在的问题,引入了声发射(AE)定位技术,成功将锚杆脱黏过程进行了三维可视化。文章详细探讨了AE定位技术的基础原理、关键算法、实验设置及数据处理流程,详细阐述了该技术在锚杆脱黏监测中的应用方法,验证了AE定位技术在锚杆拉拔脱黏实验教学中的有效性。该实验课程不仅丰富了土木工程专业的实验教学内容,而且通过结合前沿监测技术,展示了跨学科技术整合在解决复杂工程问题中的重要作用。这一教学案例促进了学生对工程实际问题复杂性的理解,激发了他们对探索未知领域的兴趣,引导他们进行创新性思考。

新文科背景下基于Blockly的机器学习实验教学平台设计与实现

在新文科建设背景下,针对文科学生编程经验少、机器学习实验上手难的问题,设计并实现一种基于Blockly编程的机器学习实验教学平台。该实验平台由教师管理端、学生实验端、系统管理端和公共模块四部分构成,采用B/S架构,由计算机编程语言Python和可视化编程工具Blockly实现。并以机器学习中的“自然语言处理”为实验教学案例,全面呈现该实验教学平台与实验教学任务结合的具体应用实践。