A 6-bit 2 GS/s ADC in 65 nm CMOS

A 6-bit 2 GS/s ADC was implemented using a 65 nm digital CMOS technology.The design is based on a single-channel flash ADC architecture,and utilizes interpolating and averaging techniques.A two-stage CML-CMOS high-speed hybrid comparator is designed for optimal speed and power performance.The total power consumption of the converter is 52 mW and the area is 0.24 mm2.The ADC achieves 42.5 dB SFDR and5.2 bit ENOB at input frequency of 123 MHz,and at Nyquist frequency 37.67 dB SFDR and 4.9 bit ENOB.     

锅炉再热器管泄漏原因分析及改造

分析了再热器管频繁泄漏的原因，认为定位块与再热器管的异种钢焊接及定位块结构的不合理是导致泄漏的主要原因，同时提出了改造方案。     

BP网络监测模型的Matlab&Delphi混合编程

结合Maflab和Delphi各自的优点,利用M文件的传输技术将Delphi和Matlab连接起来,开发出界面友好,功能强大的BP神经网络应用系统,并利用该系统建立了大坝变形监测模型.模型的实际应用表明,该系统具有建模方便、快捷、拟合预测精度较高的优点.     

焊接接头疲劳评定的等效应力强度因子法

等效应力强度因子 (equivalentstressintensityfactor,简称E SIF)法是近年来提出的一种新的疲劳评定方法 ,文中采用 16Mn钢的非承载角焊缝十字接头的疲劳试验结果对E SIF法的有效性进行研究 ,并分析讨论影响这种方法的有关因素。结果表明 ,采用等效应力强度因子法能对 16Mn钢非承载角焊缝十字接头的疲劳性能作出合理的评定 ,并能预测焊接接头的疲劳断裂位置 ,且该方法适合于焊态接头和较小焊趾半径的疲劳评定。等效应力强度因子法对应力集中区单元尺寸有一定的依赖性 ,对实际焊接接头的焊趾半径变化范围 (在 0 .15mm～ 0 .8mm内 ) ,选择焊趾半径与最小单元尺寸的比值 ρ/emin>1.7时 ,可以获得合理有效的等效应力强度因子ΔKⅠ 值计算结果 ;当焊接接头的焊趾半径较小 ( 0 .15mm～ 0 .40mm)时 ,等效应力强度因子法更为合理     

制冷机直接冷却高温超导磁体电流引线优化设计

针对制冷机直接冷却高温超导磁体电流引线的传热特性进行理论分析,对其在不同结构模式下进行漏热计算和比较,找到了大通流(kA级)电流引线结构优化设计方法和电流引线漏热与通电电流的关系式.     

Molecular engineering of microporous crystals: (III) The influence of water content on the crystallization of microporous aluminophosphate AlPO4-11

The influence of water content on the crystallization of the microporous aluminophosphate AlPO₄-11 was investigated by a combination of in situ UV Raman and ex situ XRD and NMR characterizations. Under high water content conditions (Al₂O₃:H₂O = 1:20-69), an AlPO₄-5 intermediated formed first and later co-existed with AlPO₄-11. In the last stage of crystallization, the crystalline AlPO₄-5 completely disappeared and well-crystallized AlPO₄-11 was obtained. The position of the three signals observed in the ³¹P MAS NMR spectra of the isolated solid samples did not change during the hydrothermal treatment, suggesting that the fragments containing the P site in the junction of 6- and 4-membered rings of both AlPO₄-5 and AlPO₄-11 formed first and that the environments of the P sites were very similar to those in the final structure. A significant increase of Al concentration in liquid media was observed before the appearance of XRD detectable AlPO₄-11. Under low water content conditions (Al₂O₃:H₂O = 1:15), the AlPO₄-11 was directly crystallized from the initial mixture. In situ Raman spectra showed that the 10-membered rings were complete by the time the transformation of octahedral Al to tetrahedral Al was finished and that the conformation of the protonated di-(i-propyl)amine changed little during the crystallization. The present study showed that the composition of the liquid phase is critical to the formation of a specific structure.     

Effect of radial heat conduction on effective thermal conductivity of carbon nanotube bundles

The effect of the radial heat conduction on the effective thermal conductivity of carbon nanotube (CNT) bundles is studied by the nonequilibrium molecular dynamics (NEMD) method. The hexagonal CNT bundle consists of seven (10, 10) single-walled carbon nanotubes (SWCNTs). The radial heat conduction is induced by creating the vacancy defects in some segments of the constituent CNTs. Combined with the temperature differences and the inter-tube thermal resistances at the different segments, the radial heat flow in the CNT bundle is calculated. The maximum percentage of the radial heat flow is less than 7% with the presence of four defective CNTs, while the resultant decrement of the effective thermal conductivity of the bundle is about 18%. The present results indicate that the radial heat flow can significantly diminish the axial heat conduction in the CNT bundles, which probably explains the smaller effective thermal conductivity in the CNT assemblies compared to that of the individual CNTs.     

Design of Optimal Petri Net Supervisors for Flexible Manufacturing Systems via Weighted Inhibitor Arcs

This paper develops an approach to the design of an optimal Petri net supervisor that enforces liveness to flexible manufacturing systems. The supervisor contains a set of observer places with weighted inhibitor arcs. An observer place with a weighted inhibitor arc is used to forbid a net from yielding an illegal marking by inhibiting the firing of a transition at a marking while ensuring that all legal markings are preserved. A marking reduction technique is presented to decrease the number of considered markings, which can dramatically lower the computational burden of the proposed approach. An integer linear program is presented to simplify the supervisory structure by minimizing the number of observer places. Finally, several examples are used to shed light on the proposed approach which can lead to an optimal supervisor for the net models that cannot be optimally controlled via pure Petri net supervisors.     

压力对反应合成TiB2-Cu基复合材料力学性能的影响

利用Ti，B和Cu粉的放热反应原位合成了TiB2-Cu基复合材料，研究了高压压力对复合材料力学性能的影响。结果表明，随着高压压力的提高，材料的致密度、抗弯强度、断裂韧度和硬度均有所提高，这是因为压力的提高导致了材料微观组织的细化，促进了材料的致密化。高的压力有利于获得更好的力学性能。     

EDA9033在电力负荷监测系统中的应用

EDA9033是一种智能型工频交流电参数数据采集模块,利用该模块可一次获得所需的绝大部分电参数.文章结合当前工矿企业用电的特点和电力负荷管理的方式,设计出一种基于该模块和组态软件的电力负荷监测系统.系统测量精度高,操作简单,有很高的性价比.