应变率对泡沫Al-Mg合金压缩性能的影响

在应变率分别为10^-3s^-1,600s^-1和1600s^-1条件下对开孔泡沫Al-Mg合金进行了压缩试验，测量了不同应变率下材料的压缩应力．应变(σ-ε)曲线，研究了应变率的变化对这种Al合金泡沫的压缩性能和吸能性的影响。试验结果表明：这种开孔结构的泡沫Al-Mg合金具有明显的应变率效应，随应变率的提高，其屈服强度和流动应力升高；因此，与静态下相比，动态压缩下的吸能性上升，而对应的应力也随之提高。     

铁基形状记忆合金（待续）

简介形状记忆效应(SME)的基本概念和形状记忆合金的发展。评述了Fe-Mn-Si,Fe-Mn-Si-Cr-Ni,Fe-Ni-Co-Ti和Fe-Ni-C等系铁基形状记忆合金的生长背景,特性及其SME的机制。     

析新常态下的企业人事档案管理工作

企业人事档案管理是企业管理的重要内容。新常态下,随着社会的进步、科技的发展、现代企业的标准化管理水平的提高,企业人事档案管理作用日益凸显。本文结合企业具体实际,阐述企业人事档案管理的作用,分析存在的问题,并提出相应的建议和对策。     

环鄱阳湖风沙区风电场工程水土保持措施及建议——以老爷庙风电场为例

风力作为一种清洁能源,近年来越来越得到国家的重视.环鄱阳湖风沙区风电场在建设过程中不可避免地会对土壤及植被造成一定程度的破坏,人为地加剧了水土流失.本文以老爷庙风电场工程为例,结合项目区具体特点,分区合理配置工程措施、植物措施和临时措施,有效地防治了水土流失.     

基于加窗插值FFT和动态频率的谐波检测算法

快速傅立叶变换在非同步采样的情况下存在较大的误差,因而无法在电能计量过程中获取准确的谐波能量。为了减小非同步采样对快速傅立叶变换的影响,提高电能计量的精确度,通常采用加窗的方法。本文详细分析和推导了加窗插值算法。在此基础上,采用Hanning窗,对插值算法进行改进,最后通过仿真试验,分析结果进一步验证了,改进后的谐波分析的结果与实际情况更为接近。     

演示文稿中填充效果在VB编程中的应用

利用Visual Basic1来调用PowerPoint演示文稿中的填充效果的对象,通过对填充效果属性的分析,找到了各个属性的数值,并结合Access数据库,编写了一个"填充效果"对话框,实现了"填充"效果的设置功能。     

用Excel实现对Vasicek动态模型的辅助教学

Vasicek模型作为利率期限结构理论中最基础的一种单因素模型,但在目前教学中,大多只是停留在对Vasicek模型的内容进行描述性介绍、简单的数学推导、相关变量参数的解释等,教学效果较差。试图通过对基于Excel的Vasicek模型介绍．让学生自己动手建模,从而加深对Vasicek模型的理解,实质性地提高教学效果。     

SiGe HBT单粒子效应关键影响因素数值仿真

针对锗硅异质结双极晶体管(SiGe HBT),采用半导体三维器件数值仿真工具,建立单粒子效应三维损伤模型,研究SiGe HBT单粒子效应的损伤机理,以及空间极端环境与器件不同工作模式耦合作用下的单粒子效应关键影响因素。分析比较不同条件下离子入射器件后,各端口瞬态电流的变化情况,仿真实验结果表明,不同工作电压下,器件处于不同极端温度、不同离子辐射环境,其单粒子瞬态的损伤程度有所不同,这与器件内部在不同环境下的载流子电离情况有关。     

Results of Finnish national survey on EU legislation concerning computer work

The European Directive on computer work (VDU 90/270/EEC) is implemented in the Finnish Government Decree. The aim of the present study was to evaluate the effects of the legislation and its applications in practice. The quantitative method used an online questionnaire. The respondents were employers (N = 934), employees (N = 1872) and occupational health care (OHC) units (N = 289). The majority of all these three groups considered the provisions clear and easy to understand, comprehensive, and easy to comply with. The provisions had a great impact on preventing mental overloading, arranging sight tests at the employer's cost, and on the refunding of eyeglasses for computer work. Most employers felt they did not need any more specific provisions, whereas half of the employees and OHC professionals would have liked the provisions to be more detailed. More explicit and specific regulations were also needed for practice applications in particular, as well as for the refunding of the costs of special eyeglasses for computer work. A total of 59% of the employers reported that costs of glasses are refunded, whereas the figure for employees was clearly lower (37%). OHC professionals reported that the costs of glasses were refunded in 82% of their customer workplaces. The practical conclusion is that employees' sight examinations and compensation for eyeglasses should be promoted in computer work. Moreover, ergonomic applications are best carried out in co-operation with OHC personnel.     

Cartesian product of compressible effect algebras

In the paper, we prove that is compatible with p}, the set of commutant of p, and , the projection commutant of a, are all normal sub-effect algebras of a compressible effect algebra E, and is a direct retraction on E} is a normal sub-effect algebra of an effect algebra E. Moreover, we answer an open question in Gudder’s (Rep Math Phys 54:93–114, 2004), Compressible effect algebras, Rep Math Phys, by showing that the cartesian product of an infinite number of E _i is a compressible effect algebra if and only if each E _i is a compressible effect algebra. This work was supported by the SF of Education Department of Shaanxi Province (Grant No. 07JK267), P. R. China.