第三代核主泵屏蔽电机的关键部件金属材料国产化综述

材料的国产化是设备国产化的基础,第三代核主泵屏蔽电机部分兲键材料在国内均为首次制造,能否实现国产化将会成为制约主泵电机国产化的瓶颈问题。为推迚主泵电机兲键材料的国产化迚程,同时满足后续项目的需求,依托国家科技重大专项,对部分兲键材料的国产化研究迚行了专项立项研究,取得了突破性的迚展。通过与联合单位的合作,迚行了材料试制及试验研究,实现了屏蔽套、电机轴,飞轮护环,高强度支撑筒及推力盘等兲键部件材料的国产化制造,为核主泵电机的国产化奠定了材料基础。本文主要论述了国家重大专项立项研究的兲键部件金属材料国产化情况。     

一种新的三维无线传感器网络节点定位算法

在测距的基础上,提出一种基于三角几何运算的无线传感器网络节点定位算法。该算法利用与未知节点相关的一边两角,通过空间三角几何运算,实现对未知节点的定位。对该算法的性能进行分析,并在此基础上提出一些改进的措施。仿真结果表明:该算法可以达到较高的定位精度,能够满足三维空间中对未知节点的定位需求。     

Damage detection in beams from modal and wavelet analysis using a stationary roving mass and noise estimation

This paper uses the Continuous Wavelet Transform Analysis on mode shapes for damage identification. The wavelet analysis is applied to the difference in the mode shapes between a healthy and a damaged state. The paper also includes a novel methodology for estimating the level of noise of the experimental mode shapes based on a standard Signal to Noise Ratio (SNR). The estimated SNRs are used for identifying and making emphasis on the less noisy data. Moreover, a mass attached to the structure is considered to enhance the sensitivity of the structure to damage. Modal analysis is performed for different positions of the mass along the beam. The results obtained for all the positions of the mass are combined so an averaging process is implicitly applied. The paper presents the results from an experimental test of a cantilever steel beam with different severity levels of damage at the same location. The results show that the use of the attached mass reduces the effect of noise and increases the sensitivity to damage. Little damage can be identified with the proposed methodology even using a small number of sensors and only the first five bending modes.     

On the use of calibration sensors in source localization using TDOA and FDOA measurements

The accuracy of a source location estimate is very sensitive to the presence of the random noise in the known sensor positions. This paper investigates the use of calibration sensors, each of which is capable of broadcasting calibration signals to other sensors as well as receiving the signals from the source and other calibration sensors, to reduce the loss in the source localization accuracy due to uncertainties in sensor positions. We begin the study with deriving the Cramer–Rao lower bound (CRLB) for source localization using time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements when a single calibration sensor is available. The obtained CRLB result is then extended to the more general case with multiple calibration sensors. The performance improvement due to the use of calibration sensors is established analytically. We then propose a closed-form algorithm that can explore efficiently the calibration sensors to improve the source localization accuracy when the sensor positions are subject to random errors. We prove analytically that the newly developed localization method attains the CRLB accuracy under some mild approximations. Simulations verify the theoretical developments.     

本土化酒包装设计中图案元素的应用

通过分析本土化酒包装设计中图案元素的应用,并结合几个典型的实例论述了在本土化酒包装设计的过程中图案应用的重要性和必要性。在此基础上,通过论证图案背后蕴含的意义与本土包装的相互关系,进而分析了图案的功能与形式在酒包装设计的过程中都有着不可替代的作用,也深深影响着酒包装的设计的发展。     

规范化或地方化：中国近代教会建筑的适应性策略——以岭南为中心的考察

中国近代教会建筑的适应性策略是以西方建筑的空间模式、构图法则和建筑技术为基础,融合中国传统建筑语汇,使建筑形态呈现中西混合的特征。但在推广过程中,由于面向对象和拓展目标的不同,这些中国风格的教会建筑对于中国元素的选取从一开始就面临着规划化和地方化的分歧,这一分歧在某种程度上推动了近代教会建筑形式的多样性发展。文章以岭南为中心考察中国近代教会建筑的适应性策略, 梳理教会建筑本土化发展的历史脉络,探究教会建筑规范化或地方化建筑策略的形成和内涵。     

艾萨炉燃油喷枪系统的国产化

为了满足工程需要,通过对艾萨炉燃油喷枪系统进行设计优化和制造工艺优化,提高传动部件效率,并进行材料转换选用,成功实施了对艾萨炉燃油喷枪系统的国产化,国产燃油喷枪系统的喷枪比进口喷枪使用寿命提高2倍,设备投资节约一半以上。     

砂轮锯主轴国产化改造

介绍了石钢公司连轧线砂轮锯主轴的使用情况和工作原理,分析了主轴的结构,采用理化实验、测绘、计算等方法对主轴进行国产化改造,提高了砂轮锯主轴的使用寿命和运行稳定性。     

应变率对Mg-Gd-Y合金断裂机制的影响

对Mg-Gd-Y合金分别使用准静态压缩试验机、分离式霍普金森压杆、平头弹丸侵彻加载,研究了该合金在1×10-3,1×103,1×104s-1时,应变率对其断裂机制的影响.研究结果表明,在应变率为1×10-3 s-1时,呈现出脆性解理断裂特征;当应变率增加为1×103 s-1时,动态压缩后断口除了解理片层外,还出现了热软化带,变形局域化是裂纹形核的通道,最终导致材料的失效.在应变率约为1×104 s-1时,稳定侵彻阶段,绝热剪切带是更高应变率下导致材料断裂的原因,特定位置的绝热剪切带为相变带,应变率的提高有利于形成相变带.应变率是通过影响Mg-Gd-Y合金的热软化效果而影响其断裂机制的.