试论"状--动--宾"结构的层次分析   总被引：1，自引：0，他引：1  

李汉威 《华中师范大学学报(人文社会科学版)》2002,41(5):140-142

判断“状-动-宾”结构是不是多切分结构,应该从结构,功能,意义三方面来衡量。对多切分的“状-动-宾”结构进行层次分析时,应该根据“状”,“动”,“宾”这三者之间的语义疏密关系来确定。  相似文献   

砂土地震液化的不确定性判别法综述     

张红敏 《山西广播电视大学学报》2003,8(1):73-74

通过对不同自由场地液化势估计的方法和公式进行总结和比较 ,发现剪切波速比其它波的波速更能反映地基岩土层的工作性能 ,现已为全国地基勘察规范所采用  相似文献   

变频器在切削力测量实验中的应用     

张悦  李启东  由颖  孙泰礼  郑鹏  张希川 《实验技术与管理》2011,28(1):62-64

切削力是金属切削中的重要参数之一,与切削速度呈驼峰曲线关系。为了使车削中的切削速度不受工件直径变化的影响而得到清晰完整的驼峰曲线,采用变频器对机床主电机进行无级调速,从而使主轴转速由主电机工作频率和调速手柄共同决定。实验结果表明无级调速可得到较理想的驼峰曲线。  相似文献   

Development of integrated precision vibration-assisted micro-engraving system     

陈华伟  程明龙  李佑杰  张德远 《天津大学学报(英文版)》2011,17(4):242-247

A novel precision vibration-assisted micro-engraving system was developed by the integration of fast tool servo and ultrasonic elliptical vibration system, in which the flexure hinge was designed to avoid backlash and PID control algorithm was established to guarantee specific precision. Apart from experimental validation of the performance of the system, various micro-V-grooves cutting experiments on aluminum alloy, ferrous material and hard cutting material were performed, in which Kistler force sensor was used to measure cutting force. Through experiments, it was clear that the vibration-assisted micro-engraving system can ensure good quality of micro-V-grooves and reduce cutting force by about 60% compared with traditional removal process without ultrasonic vibration.  相似文献   

Scratching and Turning Experiments on Machinability of Optical Glass SF6 in Diamond Cutting Process     

贾鹏  周明 《天津大学学报(英文版)》2011,17(4):280-283

To improve the machinability of optical glass and achieve optical parts with satisfied surface quality and dimensional accuracy, scratching experiments with increasing cutting depth were conducted on glass SF6 to evaluate the influence of cutting fluid properties on the machinability of glass. The sodium carbonate solution of 10.5% concentration was chosen as cutting fluid. Then the critical depths in scratching experiments with and without cutting fluid were examined. Based on this, turning experiments were carried out, and the surface quality of SF6 was assessed. Compared with the process of dry cutting, the main indexes of surface roughness decrease by over 70% totally. Experimental results indicated that the machinability of glass SF6 can be improved by using the sodium carbonate solution as cutting fluid.  相似文献   

薄壁结构件的加工工艺     

袁晓洲 《孝感职业技术学院学报》2011,(4):98-100

文章介绍了传统的薄壁结构件的加工方法及其缺陷,讨论了影响薄壁结构件加工精度的因素,提出了用高速切削加工典型薄壁结构件的方法,总结出当前机械制造业发展的方向是：努力发展数控切削技术,并向更高层次的自动化、柔性化、敏捷化、网络化和数字化制造方向推进。  相似文献   

Preparation time influences ankle and knee joint control during dynamic change of direction movements     

Patrick Fuerst  Albert Gollhofer  Dominic Gehring 《Journal of sports sciences》2017,35(8):762-768

The influence of preparation time on ankle joint biomechanics during highly dynamic movements is largely unknown. The aim of this study was to evaluate the impact of limited preparation time on ankle joint loading during highly dynamic run-and-cut movements. Thirteen male basketball players performed 45°-sidestep-cutting and 180°-turning manoeuvres in reaction to light signals which appeared during the approach run. Both movements were executed under (1) an easy condition, in which the light signal appeared very early, (2) a medium condition and (3) a hard condition with very little time to prepare the movements. Maximum ankle inversion angles, moments and velocities during ground contact, as well as EMG signals of three lower extremity muscles, were analysed. In 180°-turning movements, reduced preparation time led to significantly increased maximum ankle inversion velocities. Muscular activation levels, however, did not change. Increased inversion velocities, without accompanying changes in muscular activation, may have the potential to destabilise the ankle joint when less preparation time is available. This may result in a higher injury risk during turning movements and should therefore be considered in ankle injury research and the aetiology of ankle sprains.  相似文献   

电火花线切割3B代码编程方法     

佟玉斌  宋卫国 《烟台职业学院学报》2007,13(3):70-73

3B代码程序是国产数控电火花线切割机床最常采用的格式之一,通过例举典型模具零件的加工,重点介绍直线和圆弧的3B代码编程方法。  相似文献   

中外优秀男运动员百米动作速度时空结构的运动学特征     

谢慧松 《成都体育学院学报》2007,33(5):76-79

通过文献资料、高速摄像和对比分析的方法,对中外男运动员百米途中跑一个单步的步长、步时及人体重心轨迹进行研究,制定了短跑运动员所应达到的步频、步幅范围与跑速之间关系的模式表,为教练员科学训练提供了依据.  相似文献   

多工位母线加工机液压系统分析     

孙芹 《英才高职论坛》2007,(1)

本文主要介绍了多工位母线加工机液压控制系统,并对其冲孔单元、剪切单元和折弯单元的使用方法进行了说明。  相似文献