Pro/E二次开发关键技术的研究与应用

本文介绍了基于Pro／E智能化创建三维模型库的一种方法，并以齿轮为例探讨了对其参数化的关键技术。利用Pro／toolkit工具对Pro／E进行二次开发，采用VC编程语言建立动态链接库，不仅适于各类有一定结构形状、确定基本参数的机械零件族，且对其他工程数据模型库的设计也具有重要的参考借鉴价值。     

A 2.4 GHz low power CMOS transceiver for LR-WPAN applications

A 2.4 GHz low power transceiver for low-rate wireless personal area network(LR-WPAN)applications is presented.The optimized low-IF receiver consists of a novel current reuse RF front-end with an inductor-less-load balun LNA and quadrature mixer,and an adaptive analog baseband to reduce power and area.It achieves-94 dBm of sensitivity,-9 dBm of IIP3 and 28 dBc of image rejection.The phase-locked loop based direct phase modulated transmitter is proposed to reduce power and deliver a+3 dBm output power.The phase noise of the low power frequency synthesizer with current reuse stacked LC-VCO achieves-107.8 dBc/Hz at 1 MHz offset.An ultra-low power nonvolatile memory is used to store configuration data and save power.The chip is implemented in a 0.18μm CMOS process,and the area is less than 2.8 mm2.The transceiver consumes only 10.98 mW in the receiving mode and 13.32 mW in the transmitting mode.     

Automated X-ray recognition of solder bump defects based on ensemble-ELM

Solder bumps realize the mechanical and electrical interconnection between chips and substrates in surface mount components,such as flip chip, wafer level packaging and three-dimensional integration. With the trend to smaller and lighter electronics,solder bumps decrease in dimension and pitch in order to achieve higher I/O density. Automated and nondestructive defect inspection of solder bumps becomes more difficult. Machine learning is a way to recognize the solder bump defects online and overcome the effect caused by the human eye-fatigue. In this paper, we proposed an automated and nondestructive X-ray recognition method for defect inspection of solder bumps. The X-ray system captured the images of the samples and the solder bump images were segmented from the sample images. Seven features including four geometric features, one texture feature and two frequency-domain features were extracted. The ensemble-ELM was established to recognize the defects intelligently. The results demonstrated the high recognition rate compared to the single-ELM. Therefore, this method has high potentiality for automated X-ray recognition of solder bump defects online and reliable.     

价值链视角下哈萨克斯坦农业发展影响因素组态与路径研究——基于QCA方法的组态分析

自“一带一路”倡议提出以来，中国与哈萨克斯坦农业合作更加密切，但这种合作能否在激烈的国际市场竞争环境中进一步发展，农业投资领域的合理选择意义重大。论文从价值链视角出发，将农业价值链细分为生产链、物流链、信息链、营销链、创新链5条具有代表性的链条，以2019年哈萨克斯坦17个地州市的数据为研究样本，运用模糊集定性比较分析法（fsQCA）对哈萨克斯坦农业发展的影响因素组态与路径进行分析，研究发现：1）产销互链是形成哈萨克斯坦高水平农业价值链的主要驱动因素，该国高水平农业价值链下存在的两种条件组态分别是“生产链*营销链*（～信息链）*（～创新链）”和“生产链*物流链*营销链*（～创新链）”；2）导致哈萨克斯坦低水平农业价值链的路径则分为落后产能制约型和非农产业导向型，其中落后产能制约型的条件组态包括“（～生产链）*（～物流链）*（～信息链）”和“（～生产链）*物流链*信息链*（～营销链）*创新链”两种条件组态，非农产业导向型的条件组态则是“生产链*物流链*信息链*营销链*创新链”。结果表明：生产链和营销链是哈萨克斯坦目前农业发展的主要驱动因素，而创新链是制约该国农业高质量发展的主要瓶颈，物流链和信息链则具有发展潜力。针对以上结论提出应重点依托哈萨克斯坦部分地州市农业生产和营销方面的优势，积极发挥我国农业技术、信息技术和物流基础设施建设方面的优势，持续深化中哈双方在农业全产业链上的互补性合作，在帮助哈方摆脱“农业转型困境”的同时实现合作共赢。     

机场刚性道面无损检测理论研究

以一种新的、更符合实际的力学计算模型-移动荷载下粘弹性地基板系统来研究场道的无损检测理论，基于线性系统的叠加原理和坐标变换，建立了求解移动荷载下粘弹性地基板的动力响应广义积分公式，把运动荷载问题转化为获取位移脉冲响应函数，然后在柱坐标中利用拉普拉斯和汉克尔变换求解板在瞬时点源荷载作用下的解，再结合广义积分得到道面板在移动荷载作用下的弯沉解析解．以此为基础，采用最小二乘方准则，通过实测弯沉与理论弯沉相拟合，快速识别出E．通过实例计算，表明本文结果正确，基本理论和方法可应用于无损检测技术中臬获取地基模号E。     

湿法磷酸的工艺研究进展

介绍了以磷矿为生产原料的硝酸法、盐酸法、硫酸法等湿法磷酸生产工艺，并对其工艺进行了说明和比较。突出了湿法磷酸生产中的除氟问题。指出了湿法磷酸产生磷石膏废物将是制约湿法磷酸生产的主要环节。     

A low-power DC offset calibration method independent of IF gain for zero-IF receiver

A novel low-power DC offset calibration(DCOC) method independent of intermediate frequency(IF) gain for zero-IF receiver applications has been reported. The conventional analog DCOC method consumes greater power and affects the performance of the receiver. The conventional mixed-signal method requires enhanced memory to store the calibration results at different receiver gains as the DC offset is relative to the radio frequency(RF) and IF gain. A novel algorithm is presented to make the DCOC process independent of IF gain, which significantly reduces the memory area. With the proposed circuit, the receiver calibrates only once so settle-time and power consumption of the IF circuit is lowered. A DCOC circuit with the proposed method is manufactured in 0.18 μm CMOS technology that drains nearly 0 mA equivalent current from a 1.8 V power supply.     

"巾巾"有味

一袭丝巾，不但衬托出女性的秀美，而且把她们独有的气质“点亮”。如今，男士围巾也成了服装设计师们灵感进发的新宠，而且更强调其装饰性。[编者按]     

发动机曲轴专用抛丸强化清理机的研发与应用

发动机曲轴专用抛丸强化清理机是专门用于对汽车曲轴表面进行清理强化的一种清理设备。它通过抛丸器抛出高速弹丸,打击在曲轴的表面,除去表面氧化皮及其它附着物,并对表面进行强化处理。曲轴经过抛丸清理后,表面获得均匀的粗糙度,同时消除了应力集中,提高了曲轴的抗疲劳、抗腐蚀性能,延长了曲轴的使用寿命。该设备特别研发了分体式抛丸器,转速高、噪音小;研发了抛打和上卸料两个工位的转台,可实现一个工位进行工作,另一个工位进行上卸料,效率提高一倍。