Research on the Deep Integration Mechanism of National Fitness Campaign and College Physical Education Teaching:Taking Guangdong University of Science and Technology as an Example

By using the methods of literature review,questionnaire survey,and expert interview,this paper discusses and analyzes the deep integration mechanism of national fitness campaign and college physical education teaching,in order to promote the development of college physical education teaching reform,expand ideas,explore new fields,and provide novel development directions.The purpose is to enhance the national physical quality,improve the public service system,enhance the health awareness of the citizens,and provide guidelines for promoting the development of sports.

Modeling and Optimal Design of Planar Linkage Mechanism of Coupled Joint Clearances for Manufacturing

The uncertainty of the mechanism motion error is mostly caused by the manufacturing process,so the motion error cannot be effectively predicted at the design phase.The problems of manufacturing complexity and the relationship between design and manufacturing are analyzed,and the influence of dimensional tolerance and fit tolerance on the motion accuracy of the system is considered in the design process.Then based on the Monte Carlo simulation,an optimal design model of planar linkage mechanism is set up.A typical offset slider-crank mechanism is used as an illustrative example to carry out the optimal design.Compared with the result of typical robustness design,the similar variation characteristics of the mean value and the standard deviation can be found,so the proposed method is effective.The method is furthermore applied in the optimization of the schemes with different fit tolerances and the prediction of motion errors in the design phase is achieved.A set of quantitative evaluation system for mechanism optimal design is provided.Finally,a basic strategy is presented to balance the motion precision and manufacturing cost.

综放开采下煤层底板采动破坏深度预测

以淮南顾北煤矿12121工作面为工程研究背景,收集了22个综放工作面地质资料和底板破坏深度实测值,通过线性回归分析建立新的预测模型,得出了底板采动破坏深度的拟合公式,准确计算出底板采动破坏的深度,并将计算值及3个传统统计公式计算结果与现场实测值进行对比分析,得出新预测模型拟合公式比传统统计公式预测精度更高、误差更小,更接近实测值,基本可以满足现场需要。研究成果对淮南矿区煤层综放开采水害防治具有较高的实用价值,为类似工作面的水害防治提供更为科学的依据。

中职院校机械设备装调实践课程教学模式探索与优化

机械设备装调实践课程可以培养学生机械设备的安装、调试和维护能力,提高实际操作水平。该文通过分析机械设备装调实践传统课程存在的理论与实践脱节、教学资源有限等问题,提出一种基于项目导向的教学方法,通过实际项目和任务引导学生进行自主学习和实践操作,增强学生的动手能力和问题解决能力。同时,优化教学资源配置,充分利用现代化教学工具和设备,促进教学质量的提升,旨在为中职院校机械专业教学改革提供参考。

机械变速拖拉机牵引试验特性研究和分析

牵引试验是农业拖拉机试验鉴定中最重要的试验之一,且牵引功率是衡量拖拉机动力性能和经济效益的重要技术指标。为此,对不同档位下拖拉机行驶速度、牵引功率、牵引力和滑转率等参数进行测量,结合测量得到的数据结果绘制参数关系曲线图,分别绘制了牵引力和行驶速度、牵引功率和行驶速度、牵引力和驱动轮滑转率、牵引功率和牵引比油耗的曲线变化图。同时,运用数学运算得出各参数间一次线性和二次多项式的拟合方程,对比决定系数R2值,得出最真实的回归方程。试验结果表明:得出的回归方程对研究农业拖拉机牵引功率试验有一定的指导和应用价值,可对牵引功率试验中的测量参数进行提前预测。

Mechanical properties and constitutive behaviors of as-cast 7050 aluminum alloy from room temperature to above the solidus temperature

The mechanical properties and constitutive behaviors of as-cast AA7050 in both the solid and semi-solid states were determined using the on-cooling and in situ solidification approaches, respectively. The results show that the strength in the solid state tends to increase with decreasing temperature. The strain rate plays an important role in the stress–strain behaviors at higher temperatures, whereas the influence becomes less pronounced and irregular when the temperature is less than 250°C. The experimental data were fitted to the extended Ludwik equation, which is suitable to describe the mechanical behavior of the materials in the as-cast state. In the semi-solid state, both the strength and ductility of the alloy are high near the solidus temperature and decrease drastically with decreasing solid fraction. As the solid fraction is less than 0.97, the maximum strength only slightly decreases, whereas the post-peak ductility begins to increase. The experimental data were fitted to the modified creep law, which is used to describe the mechanical behavior of semi-solid materials, to determine the equivalent parameter fGBWL, i.e., the fraction of grain boundaries covered by liquid phase.

Experimental Study on the Resistance and Splash Performances of Water Collecting Devices for Mechanical Draft Cooling Towers

In recent years,water collecting systems,with the associated advantages of energy saving and noise reduction,have become the foundation for the development of a scheme to optimize the structure of cooling towers.To explore the feasibility of this approach for mechanical draft cooling towers,a small-scale experimental device has been built to study the resistance and splash performances of three U-type water collecting devices(WCDs)for different water flow rates and wind speeds.The experimental results show that within the considered ranges of wind speed and water flow rate,the pressure drop of the different WCDs can vary significantly.The resistance and local splash performances can also be remarkably different.Some recommendations about the most suitable system are provided.Moreover,a regression analysis of the experimental data is conducted,and the resulting fitting formulas for resistance and splash performance of WCD are reported.

基于“Fit for 55”草案的大型集装箱船营运碳排放分析

欧盟委员会提出了“Fit for 55”草案,以市场机制的措施应对欧盟区内航运业的减排目标。为评估今后船舶在欧盟区内需要缴纳的碳税及罚金,该文讨论了欧盟税费的组成及影响因素,提出3种降低欧盟税费的措施,并以大型集装箱船为研究对象,分别对3种措施进行了对比分析。研究表明:使用低碳或零碳燃料是未来降低碳排放的趋势。

基于神经网络的力矩补偿动力学参数辨识

针对机械臂刚柔耦合动力学模型拟合精度不高的问题,在分析动力学参数对各关节力矩影响的基础上,提出了一种基于神经网络力矩补偿的动力学参数辨识方法.首先,对动力学模型进行线性化分析,得到最小惯性参数集,设计机械臂激励轨迹,并采集各关节数据集.其次,搭建神经网络架构,对不同隐藏层数的神经网络模型的训练效果比较,证明了本文模型的准确性.将关节位置、速度、加速度数据集作为网络架构输入,经过神经网络学习后提取出各关节力矩.最后,对算法辨识出来的模型进行验证,以模型预测力矩的均方根误差为评判标准,关节拟合力矩结果表明,本文所用方法相较刚体逆动力学有更好的拟合精度,减少了关节摩擦等非线性因素对辨识实验的影响,得到更精准的动力学模型,对机械臂系统有更好的控制效果.

高温后风积沙混凝土力学性能与微观结构试验研究

本文将0%、10%、30%、50%的风积沙等质量替代普通河砂制备成风积沙混凝土,对其在温度20、200、400、600、800℃作用下的外观形貌变化、质量损失情况、抗压强度、抗折强度进行了试验研究;通过折压比的方法分析了风积沙混凝土在不同温度和不同风积沙掺量下力学性能的演变;通过扫描电子显微镜(SEM)研究了不同温度作用下风积沙混凝土内部微观结构的演化过程,并对微观结构机理进行了分析。结果表明:适量风积沙的掺入可以增加水化产物,优化混凝土的孔隙结构,减小混凝土内部界面过渡区厚度,使混凝土内部结构更密实,力学性能得以提升,并能延缓高温作用后混凝土裂缝与孔隙的生成;然而,风积沙掺量过多则会起到相反的效果,使高温后混凝土力学性能下降。本研究可为风积沙混凝土的应用及高温后风积沙混凝土结构的评定提供依据。

衍射仪的机械制造误差对拟合可信度极限的影响

全谱结构拟合是获得研究对象精细结构的一种重要方法,X射线多晶衍射仪测试的角度准确度直接影响全谱结构拟合的正确性和可信度,而测角仪的机械制造误差是影响测量角度准确度不可忽视的因素。该文采用模拟计算方法对由蜗轮蜗杆系统的制造误差造成的X射线多晶衍射全谱拟合结果的可信度进行了分析,结果表明对theta-theta衍射仪而言,机械制造的角度准确度至少要达到±0.003°,拟合结果才是有可信度的,所以只有采用直接在衍射仪轴上安装有高准确度的圆光栅的方式,才能提供符合当前物质结构分析的要求。该文具体给出了圆光栅的准确度要求。

Lung mechanics in canine oleic acid-induced respiratory distress syndrome model

In mechanically ventilated anesthetized dogs (pentobarbital sodium,30mg/kg) with acute lung injury induced by intravenous infusion of oleic acid(OA),changes in airflow,lung volume,and tracheal (Pao),transpulmonary (Ptp)and esophageal (Pes) pressures were measured.Changes in lung mechanics werestudied before and after OA infusion at intervals,during an observation periodlasting 4h,using curve-fitting method,interrupter technique and pressure-volume(PV) loops measurement.The main findings are listed as follows:(1)Complianceand functional residual capacity (FRC) showed a marked decrease,while Pao andPtp showed a marked increase within 2h after OA.(2) Airflow resistance atexpiratory phase estimated by the curve-fitting method showed a marked increaseafter OA.(3)PV loops of the lungs or total respiratory system showed similarchanges 4h after OA,characterized by the presence of an inflexion point at theinflation limb,increased hysteresis and rightward and downward shift of the loop.It is suggested that use of the curve-fitting method in combination with the PVloop for the total respiratory system would be more appropriate for monitoringlung mechanics during mechanical ventilatory support of ARDS patients.

融合边缘感知与统计纹理知识的输电线路金具锈蚀检测

针对输电线路金具目标小、背景环境复杂和锈蚀区域不规则等问题,提出了一种融合边缘感知与统计纹理知识的输电线路金具锈蚀检测算法。首先通过改进YOLOv7模型检测金具,然后利用改进Res-UNet模型对检测的金具进行锈蚀分割,加入SE(squeeze-excitation)注意力提高模型的稳定性,引入统计纹理知识模块(statistical texture knowledge module,STM)和边缘感知模块(edge-aware module,EAM),提出一种知识融合模块对边缘感知和统计纹理知识进行融合,提高对锈蚀分割精度。实验结果表明,检测和分割模型mAP分别提高了2.8百分点和7.7百分点。

航空插头气动压装机构设计

设计了一种航空插头压装机构,主要由气动压装台、定位装置和定位压装头组成,可实现具有压装方向性要求的航空插头快速压装到工件上,压装过程可确保航空插头不受损坏,且能准确压装到位。该机构的定位压装头设计有特殊的定位、定方向、零件保持等结构,解决了航空插头压装时易受损坏、难定位、难定方向等技术难题,确保了航空插头的顺利装配。

健身气功参与社区健康促进的协同嵌入机制研究——基于在YT市QIQuan社区的实践

健身气功以何种方式参与社区健康促进从而实现自身价值是时代赋予民族传统体育研究的重要课题。文章在深入开展社区状况调查、组建健身气功队伍、指导社区体育锻炼等一系列实践活动的基础上,探索出一套推动健身气功参与社区健康促进的协同嵌入机制。该机制包括多主体嵌入、多要素嵌入和多阶段嵌入三个方面的内涵。即政府、社工机构、高校、社区居委会为实现共同目标建立协同关系,分别从政策支持、项目运作、社区教育和社区动员四个方面,将健身气功的政策形态、项目形态和知识形态转化为社区居民的生活形态,从而实现健身气功嵌入社区健康促进的目标。

基于中西医临床病证特点的免疫性血小板减少动物模型分析

原发免疫性血小板减少(ITP)是一种出血性疾病,发病机制目前尚不明确,为了进一步探究ITP发病机制和临床新药的研究,故通过查阅大量国内外关于免疫性血小板减少模型的相关文献,参照中西医病因病机和临床疾病诊断标准,总结分析ITP相关动物模型特点和与临床吻合度。发现应用最为广泛的是抗血小板血清诱导法,其临床吻合度与病证结合脾不统血、气不摄血模型吻合度均较高,模型造模方式简单,可重复性强。但大多数模型将西医作为评价指标,模型无法完全模拟ITP完整发病过程和状态,缺少中医证候描述,在模型发展仍需进一步完善。

“制度-数字”双轮驱动全民健身智慧治理的逻辑理路、现实困境与实践路径

全民健身智慧治理对促进体育治理现代化、建设体育强国具有重要意义。运用文献资料、逻辑分析等研究方法,阐释“制度-数字”双轮驱动全民健身智慧治理的基本内涵、逻辑理路、现实困境与实践路径,为实现全民健身智慧治理提供理论支持和实践依据。研究认为,“制度-数字”双轮驱动全民健身智慧治理是一种以制度和数字技术共同驱动的综合治理过程。该过程坚持以人民为中心和成果共享为逻辑起点,通过制度的规范引领与监督激励、数字技术的精准决策与互动共享、制度与数字技术之间的优势互补与协同创新等,共同驱动全民健身智慧治理。全民健身智慧治理仍然面临法治体系有待健全、治理机制尚需完善、数字鸿沟现象突出、数据共享与隐私保护之间存在矛盾等现实困境。据此提出实践路径:健全法治体系,推进智慧治理法治建设;完善治理机制,提升智慧治理效率;弥合数字鸿沟,促进社会公平;平衡数据共享与隐私保护,优化智慧治理服务。

Integration mechanisms of transgenes and population fitness of GH transgenic fish

It has been more than 20 years since the first batch of transgenic fish was produced. Five stable germ-line transmitted growth hormone (GH) transgenic fish lines have been generated. This paper reviews the mechanisms of integration and gene targeting of the transgene, as well as the viability, reproduction and transgenic approaches for the reproductive containment of GH-transgenic fish. Further, we propose that it should be necessary to do the following studies, in particularly, of the breeding of transgenic fish: to assess the fitness of transgenic fish in an aqueous environment with a large space and a complex structure; and to develop a controllable on-off strategy of reproduction in transgenic fish.

福建仙游震群的应力场及其成因分析

利用双差定位法对2010年8月1日至2014年12月31日福建仙游地区中国地震台网中心记录到的地震群进行重定位,并采用P波初动的方法求解出该震群的159个震源机制解,显示该震群的震源机制解结果与背景构造应力场表现明显不一致。为了进一步探究差异性存在的原因,将得到的震群震源机制解结果分区域和分深度求解应力场,结果显示:金钟水库的东南部附近应力方向更远离背景构造应力方向,并且应力形因子小于0.5,中间轴呈现为拉张应力;随着深度的增加,应力场的方向也更接近背景构造应力场的方向。此外,根据前人研究推断该区域应力方向发生偏转是由于太平洋板块在深部的低角度俯冲挤压导致浅部张开,应力呈现为东西向拉张所致。在上述两原因的共同作用下,使得经震源机制解反演出的应力场结果与背景应力场差别较大。

智慧社区健身中心项目中行动者网络利益共同体整合机制研究

智慧社区健身中心项目的成功实践,实质上是各异质行动者间互动与博弈的结果。该研究采用访谈法、实地调查法等方法,对案例中行动者网络利益共同体的创建过程及整合机制进行了“深描”。研究认为:X街道社区健身中心项目包含地方政府、自治性群众组织、专业技术公司以及社区公众等多个异质行动者,作为核心行动者的地方政府通过强制通行点(OPP)的设置、利益赋予、任务与角色分配、动员等过程,使得公共利益和个人利益达到有效平衡,进而形成了行动者网络利益共同体。但在具体实践中,各行动者间关系异化、权责混乱、利益价值取向分化等“异议”仍旧存在。为此,研究提出了建立以“主导—配合”式互动合作关系的运行机制,以权责明晰为前提的协作机制,以利益共享为目标的动力机制等整合机制,以期实现行动者网络利益共同体的稳定运行。