变频调速系统中电动机和变频器选择及问题分析

本文分析了选用标准笼形电动机的容量计算方法、问题分析和选用变频器的型式、容量、注意事项。     

人骨骼中~(228)Th、~(230)Th和~(232)Th含量的同时测定

本文介绍了用α谱仪同时测定人骨骼中~(228)Th、~(230)Th和~(232)Th含量的方法。样品用浓 HNO_3和 H_2O_3湿灰化,草酸钙共沉淀载带、CL-5208萃淋树脂和743阳离子交换树脂联合分离后,电沉积制源,在低温半导体α谱仪上测量。该方法对~(234)Th的全程回收率为95.0±1.7%,对铀和镭的去污系数分别为6.3×10~4和1.5×10~3,对~(228)Th、~(230)Th、~(232)Th 的探测下限分别为0.432、0.135和0.108Bq/kg(鲜重)。     

提高检测数据准确性 促进选钼生产稳定高效

本文从6个方面对选钼2个作业段的取样方式进行了校验,通过对检测数据的比对分析,找出了选钼2个作业段数据存在矛盾的原因,并针对原因采取了有效的措施,保证了检测数据的准确性,促进了选钼生产的稳定高效。     

A novel open-loop high-speed CMOS sample-and-hold

A new open-loop high-speed CMOS sample-and-hold is presented. Based on new method for further reduction of voltage-dependent charge injection, a new CMOS sample-and-hold was designed. Simulation results confirm the effectiveness of this method. Over 10 dB improvement in signal-to-noise ratio, compared to the signal-to-noise ratio of conventional bottom plate sampling S/Hs was achieved with this method. A comparison between newly designed S/H and the bottom-plate sampling S/H is presented.     

Integrated development of CFRP structures for a topless high performance vehicle

When modern saloon cars are re-engineered as convertibles (or roadsters) it is typical for them to lose 50% or more of the body’s torsional rigidity. Consequently the vehicles rarely handle quite as crisply, nor do they ride as well as the coupes from which they derived. This paper highlights the fundamental contributions of advanced composites in achieving the desired value of handling of the Murcièlago Roadster without penalizing the overall weight of the vehicle. To compensate for the absence of the roof structure, the vehicle was strongly redesigned by introducing new structural members and reinforcing existing critical components. A new all-carbon/epoxy composite sub-frame, which spans the entire engine bay, is comprised of elliptical tubular members, and it is the first of its kind in a production vehicle. Engineering of the sub-frame, from preliminary design to manufacturing decisions, is the focus of this paper, and is achieved through a Building Block approach that sets the program within the Integrated Product Development (IPD) strategy that the Advanced Composites Division of Automobili Lamborghini S.p.A. employs for its technology demonstrators. The strategy consists in a concurrent analytical and experimental development of the product, from the initial conceptual design and coupon testing, through the stages of element and subcomponent engineering, to final component manufacturing.     

玻璃钢管道的特点,设计原理及选用时的注意事项

本文旨在通过对玻璃钢管道及其标准的发展历史、产品特点、基本设计原理、质量影响因素及选用时应注意的事项等方面的介绍，使用户与工程设计人员对该产品有一个比较全面的了解，以便更好地选用并受益于这种管材。     

硅中硼离子注入校准样品的研制

本文主要介绍了硅中硼离子注入校准样品的制备与研究。分别用三台SIMS仪器对样品进行了深度剖析与比对,并对用作校准目的的样品主要参数进行了定值。     

挖掘机工作装置实验样本长度确定方法及程序系统

本文通过对某液压挖掘机工作装置实验样本长度的研究,详细讨论了样本长度的确定方法,重点分析了趋势曲线拟合法,提出了样本长度精度区间分析的方法,并在处理大量实验数据的基础上,从载荷分布及寿命估算的角度做了实际的验证.编制了应用程序,使样本长度确定至寿命估算整个过程程序化.     

高速宽带取样-滤波数字化系统中高斯滤波器的设计

本文基于频域逼近的方法提出了高斯滤波器的设计理论,得出了带宽归一化的各阶高斯滤波器的通用计算公式。并对高斯滤波器的数字化时间窗口、回复时间参数等进行了计算。