以动态心率为指标的体力疲劳的评价方法研究

对４０名男子和３５名女子在运动过程中和运动结束后体力恢复过程中的心率变化情况进行试验研究。证明在体力劳动中,心率恢复期和动态心率与体力疲劳程度之间存在着密切的联系。首次建立了以心率恢复期为指标的体力疲劳的分级方法。建立了用心率综合指标和相对心率综合指标来划分体力疲劳的方法,该评价方法的建立将使体力疲劳的动态测定成为可能。     

以动态心率为指标的体力劳动强度评价方法研究

对人体在带负荷运动过程中和运动结束后体力恢复过程中的心率、耗氧量和能量代谢率的变化情况进行试验研究,证明心率与耗氧量和能量代谢率之间具有良好的线性关系。试验结果还证明在同等体力负荷下活动,男女之间的心率和能量代谢率存在着较大的差异,女子的能量代谢率比男子的能量代谢率低１５ ％ 左右,但其心率则比男子的心率高１０ ％ 左右。首次按男女性别差异提出了以心率和相对心率为指标的体力劳动强度分级方法,从而使体力劳动强度评价变得可靠有效。     

白光干涉型Michelson光纤扫描干涉仪

介绍了一种白光干涉型Ｍｉｃｈｅｌｓｏｎ位移传感器，Ｍｉｃｈｅｌｓｏｎ干涉仪的一臂由光纤Ｆ－Ｐ腔构成，作为传感头，另一臂由电磁位移器带动的反射镜构成，提供相位补偿。理论分析和实验结果表明，在１５０μｍ的动态范围内，该传感器的位移测量重复性达到０．５μｍ，测量不确定度为．５μｍ。本文还提供了进一步提高测量精度和响应速度的方法。     

SiOx镀膜包装材料及其加工技术

ＳｉＯ_ｘ镀膜包装材料及其加工技术王建清ＳｉＯ_ｘＦｉｌｍａｎｄＩｔ′ｓＰｒｏｃｅｓｓＴｅｃｈｎｏｌｏｇｙ￥ＷａｎｇＪｉａｎｑｉｎｇＡｂｓｔｒａｃｔ：ＳｉＯｘｆｉｌｍｉｓａｎｅｗｐａｃｋａｇｉｎｇｍａｔｅｒｉａｌｕｓｅｄｆｏｒｆｏｏｄ，ｗｈｉｃｈｉｓＰ...     

二价离子替代的Nasicon及其应用研究

含二价阳离子的Ｎａｓｉｃｏｎ，Ｍ￣（２＋）Ｎａｓｉｃｏｎ（Ｍ＝Ｍｇ、Ｃａ、Ｓｒ、Ｚｎ）可由母体Ｎａ＿３Ｚｒ＿２Ｓｉ＿２ＰＯ＿（１２）（Ｎａｓｉｃｏｎ）为起始原料与相应的二价离子的盐浓液或熔盐进行离子交换而制得。Ｘ射线衍射分析结果表明离子交换后的产物Ｍ￣（２＋）－Ｎａｓｉｃｏｎ大多保持原母体的Ｃ＿（２／ｃ）结构。交流阻抗技术测定的电导率数据显示含不同的二价替代离子的Ｎａｓｉｃｏｎ的电导率相差甚大。其中最好的是Ｍｇ￣（２＋）－Ｎａｓｉｃｏｎ，其电导率在４００℃时可达到１．４８×１０￣（－２）Ｓ／ｃｍ。Ｍｇ￣（２＋）－Ｎａｓｉｃｏｎ用作微功率固态电池Ｍｇ／ＣｕＣｌ的电解质，该电池的开路电压为２．０７Ｖ，短路电流为１ｍＡ。平均放电电压为１．６Ｖ，电池的放电容量是３．４ｍＡＨ。     

论包装行业推广应用设备诊断技术的几个问题

论包装行业推广应用设备诊断技术的几个问题严学书ＥｑｕｉｐｍｅｎｔＤｉａｇｎｏｓｉｓｉｎＰａｃｋａｇｉｎｇＩｎｄｕｓｔｒｙ￥ＹａｎＸｕｅｓｈｕＡｂｓｔｒａｃｔ：Ｅｑｕｉｐｍｅｎｔｄｉａｇｎｏｓｉｓｍａｙｃｕｒｂｍａｉｎｔａｉｎｂｌｉｎｄｌｙ，ｒｅｄｕｃ...     

Fischer—Tropsch合成反应机理研究进展

本文论述了Ｆｉｓｃｈｅｒ－Ｔｒｏｐｓｃｈ合成反应研究的意义及其重要性。概述了Ｆｉｓｃｈｅｒ－Ｔｒｏｐｓｃｈ合成反应机理研究中的几种主要反应机理模型的内容，最后讨论了Ｆｉｓｃｈｅｒ－Ｔｒｏｐｓｃｈ合成反应机理研究中存在的问题及未来研究方向。     

Agile Manufacturing of Complex Moulds For Punch Devices

ＡｇｉｌｅＭａｎｕｆａｃｔｕｒｉｎｇｏｆＣｏｍｐｌｅｘＭｏｕｌｄｓＦｏｒＰｕｎｃｈＤｅｖｉｃｅｓＱｉｎＺｈｅｎｇＬｕＢｉｎｇｈｅｎｇＬｉｕＴａｉｐｉｎｇＺｈａｎｇＹａｎｇＸｉ’ａｎＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｘｉ’ａｎ，７１００４９，Ｐ．Ｒ...     

应用VisualBasic开发深基坑支护工程数据库的几个问题

介绍了应用面向对象的可视化编程语言ＶｉｓａｕｌａＢａｓｉｃ开发数据库应用程序的特点,重点论述了结合深基坑支护工程应用系统的需要,利用ＶｉｓｕａｌＢａｓｉｃ０ 设计和建立。     

包装设计的评价

包装设计的评价陆佳平ＥｖａｌｕａｔｉｏｎｏｆＰａｃｋａｇｉｎｇＤｅｓｉｇｎ￥ＬｕＪｉａｎｇｐｉｎｇＡｂｓｔｒａｃｔ：Ｔｈｅａｕｔｈｏｒｆｉｒｓｔｄｉｓｃｕｓｓｅｓｔｈｅａｉｍａｎｄｂａｓｉｓｏｆｅｖａｌｕａｔｉｏｎｏｆｐａｃｋａｇｉｎｇｄｅｓｉｇｎ，...     

Evaluation of materials for artificial heart valves

The heart of a normal human being beats about 38 million cycles every year. An artificial heart valve, to perform at this rate in the adverse conditions inside the heart for 20 years or more, should be highly wear-resistant with excellent fatigue strength. Thus, the study of mechanical and physical properties of the materials intended for use in artificial valves becomes an inseparable part of the valve development process itself. The physical and mechanical requirements of the materials used in the Chitra heart valve have been evaluated by studying their water absorption, adhesive wear and abrasive properties. The mechanical durability of the device has been assessed by accelerated life cycle testing. The test systems developed for the above are described here. The results show UHMW-PE to be a highly wear-resistant material suitable for the occluder. The accelerated wear tests show that the valve with Haynes-25 alloy cage and UHMW-PE disc has durability in excess of 50 years.     

Numerical simulation of fatigue crack propagation in compressive residual stress fields of notched round bars

In this paper, the influence of the residual compressive stresses induced by roller burnishing on fatigue crack propagation in the fillet of notched round bar is investigated. A 3D finite element simulation model of rolling has allowed to introduce a residual stress profile as an initial condition. After the rolling process, fatigue loading has been applied to three‐point bending specimens in which an initial crack has been introduced. A numerical predictive method of crack propagation in roller burnished specimens has also been implemented. It is based on a step‐by‐step process of stress intensity factor calculations by elastic finite element analyses. These stress intensity factor results are combined with the Paris law to estimate the fatigue crack growth rate. In the case of roller burnished specimens, a numerical modification concerning experimental crack closure has to be considered. This method is applied to three specimens: without roller burnishing, and with two levels of roller burnishing (type A and type B). In all these cases, the computational finite element predictions of fatigue crack growth rate agree well with the experimental measurements. The developed model can be easily extended to crankshafts in real operating conditions.     

The fatigue crack growth rate in L-72 Al-alloy plate specimens with cold worked holes

A fatigue crack growth rate study has been carried out on L-72 aluminium alloy plate specimens with and without cold worked holes. The cold worked specimens showed significantly increased fatigue life compared to unworked specimens. Computer software is developed to evaluate the stress intensity factor for non-uniform stress distributions using Green's function approach. The exponents for the Paris equation in the stable crack growth region for cold worked and unworked specimens are 1.26 and 3.15 respectively. The reduction in exponent value indicates the retardation in crack growth rate. An SEM study indicates more plastic deformation at the edge of the hole for unworked samples as compared to the worked samples during the crack initiation period.     

基于ZigBee的风光互补发电监测系统无线传感器的研究1009-914X

针对气象环境对风光互补发电系统影响重大及传统传感器测量物理量单一等原因,提出了一种基于ZigBee的无线传感器网络的设计方案。该传感器集风速、风向、光照强度、温度、湿度为一体,网络容量大、功耗低、易于扩充并且支持自组网。根据监测系统的技术要求,设计了无线传感器结构和硬件电路,井给出了软件流程。     

Prediction of short fatigue crack growth of Ti‐6Al‐4V

It is observed that the short fatigue cracks grow faster than long fatigue cracks at the same nominal driving force and even grow at stress intensity factor range below the threshold value for long cracks in titanium alloy materials. The anomalous behaviours of short cracks have a great influence on the accurate fatigue life prediction of submersible pressure hulls. Based on the unified fatigue life prediction method developed in the authors' group, a modified model for short crack propagation is proposed in this paper. The elastic–plastic behaviour of short cracks in the vicinity of crack tips is considered in the modified model. The model shows that the rate of crack propagation for very short cracks is determined by the range of cyclic stress rather than the range of the stress intensity factor controlling the long crack propagation and the threshold stress intensity factor range of short fatigue cracks is a function of crack length. The proposed model is used to calculate short crack propagation rate of different titanium alloys. The short crack propagation rates of Ti‐6Al‐4V and its corresponding fatigue lives are predicted under different stress ratios and different stress levels. The model is validated by comparing model prediction results with the experimental data.     

A new muscle fatigue and recovery model and its ergonomics application in human simulation

Although automatic techniques have been employed in manufacturing industries to increase productivity and efficiency, there are still lots of manual handling operations, especially for assembly and maintenance operations. In these operations, musculoskeletal disorder (MSD) is one of the major health problems due to overload and cumulative physical fatigue. With combination of conventional posture analysis techniques, digital human modeling and simulation (DHM) techniques have been developed and commercialized to evaluate the potential physical exposures. However, those ergonomic analysis tools are mainly based on posture analysis techniques, and until now there is still no fatigue index available in commercial software to evaluate the physical fatigue effectively. In this paper, a new muscle fatigue and recovery model is used to evaluate joint fatigue level in manual handling operations. The physical fatigue in a special application case is described and analyzed using digital human simulation techniques.     

FATSYS,a computer controlled system for fatigue crack growth data collection using an Amsler Vibrophore

A system of hardware and software developed for collecting fatigue crack growth data from an Amsler Vibrophore fatigue machine is described. The system allows testing at constant, increasing and decreasing stress intensity factor ranges ($\text{ΔK}$), and it generally complies with the proposed ASTM standards on fatigue crack growth testing. The system has proven to be extremely beneficial particularly for work at growth rates approaching threshold, where manual methods are tedious and time consuming.     

Experimental and numerical study of fatigue crack growth of aluminum alloy 2024-T3 single lap simple bolted and hybrid (adhesive/bolted) joints

In this paper, the effects of tightening torque (clamping force) on the fatigue crack growth rate and stress intensity factors in cracked single lap simple bolted and hybrid (adhesive/bolted) joints have been studied experimentally and numerically. To do so, series of fatigue crack growth tests for two different amounts of tightening torque in Aluminum alloy 2024-T3 pre-cracked joints have been carried out to record the fatigue crack growth and also the fatigue life of specimens. In the numerical part, finite element method was employed to obtain the stress intensity factors and also the effective stress intensity factor ranges for different crack lengths to explain the behavior of fatigue crack propagation. It was found that the hybrid joint has longer fatigue crack growth life compared to the simple bolted joint at a given bolt tightening torque. The results also showed that a higher bolt tightening torque provides improved fatigue crack growth life for both types of the joints.