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31.
���þ��ܰ�ȫ�Բ������������� 总被引:1,自引:1,他引:0
本文通过对在用钻机井架的现场实际测试,建立数据库、测评模型,对实测的数据用计算机技术进行分析,提出了初始弯曲应力;数据正态分布检验——x~2检验;建立回归方程;在给定置信度下测评当前承载能力的技术概念。解决了在用钻机A型井架的安全性评估问题,是一种较为合理、可靠、科学的测评技术和方法。 相似文献
32.
The authors review the principles of reconstructive surgery for lower limb salvage after severe lower limb trauma to determine factors that have been used as decision-making criteria for limb salvage or amputation in severe lower extremity injuries and the methods of reconstruction and their outcome. The use of scoring systems and their value in acute decision making (primary amputation or limb salvage) are described. Soft-tissue reconstructive techniques, with emphasis on the use of flaps and the importance of selecting the best technique and time for the reconstruction are reviewed. Skeletal reconstructive techniques are described, including available options and currently held views on indications and use of the best contemporary methods. It is essential for the physician to make a good initial decision on the need for primary amputation or limb salvage. A multidisciplinary approach is fundamental to successful salvage. 相似文献
33.
A simple amplitude shift keying (ASK) optical link is demonstrated by using a low-cost self-pulsating laser diode and an envelope detector for a low-cost broadband local area network. A link sensitivity of -22 dBm was achieved at 200 Mbit/s. Because the self-pulsation frequency can be tuned by the bias current, frequency division multiplexing can be simply implemented for multiuser applications 相似文献
34.
本文分析了校园网上商店建设的背景,提出了建设校园网上商店的必要性。运用ASP.net技术,提出了校园网上商店的商业模式分析、体系结构、平台设计方案和实现方法。 相似文献
35.
Application of model predictive control strategy based on fuzzy identification to an SP-100 space reactor 总被引:1,自引:0,他引:1
In this work, a model predictive control method combined with fuzzy identification, is applied to the design of the thermoelectric (TE) power control in the SP-100 space reactor. The future TE power is predicted by using the fuzzy model identified by a subtractive clustering method of a fast and robust algorithm. The objectives of the proposed fuzzy model predictive controller are to minimize both the difference between the predicted TE power and the desired power, and the variation of control drum angle that adjusts the control reactivity. Also, the objectives are subject to maximum and minimum control drum angle and maximum drum angle variation speed. The genetic algorithm that is effective in accomplishing multiple objectives is used to optimize the fuzzy model predictive controller. A lumped parameter simulation model of the SP-100 nuclear space reactor is used to verify the proposed controller. The results of numerical simulations to check the performance of the proposed controller show that the TE generator power level controlled by the proposed controller could track the target power level effectively, satisfying all control constraints. 相似文献
36.
37.
Ying Bai Yanfeng Yin Na Liu Bingkun Guo Hongjun Shi Jianyong Liu Zhaoxiang Wang Liquan Chen 《Journal of power sources》2007
As the continuance of our series study on LiCoO2 surface modification, the complicated traditional surface coating method is replaced with simple addition of amorphous YPO4 and Al2O3 in commercial LiCoO2 or in commercial electrolyte based on our understanding to the improvement mechanism of surface modification. Comprehensive studies by X-ray photoelectron spectroscopy (XPS), gas chromatography and mass spectroscopy (GC–MS), inductively coupled plasma (ICP) and Fourier transformed infrared (FTIR) indicate that the products of spontaneous reaction between the additive and the LiPF6 based electrolyte are responsible for the performance improvements. 相似文献
38.
39.
Attenuations of the first (or fundamental) longitudinal guided wave modes propagating in liquid-filled steel pipes are numerically
investigated. Several filling liquids transported by the steel pipe are considered in the investigation. In the numerical
modeling stage, a sink is considered for abandoning standing wave modes caused by the internal liquids; hence, the attenuation
dispersion curves become simpler. From the attenuation dispersion curves, two specific attenuation values corresponding to
1 MHz and 2.68 MHz are selected; then, the concept of parametric density is introduced to predict attenuation for a certain
filling material. With this concept, it is possible to approximately calculate attenuation values without a complex numerical
attenuation calculation. This investigation may provide fundamental data to inspectors using ultrasonic guided-wave techniques
in the petrochemical industry and in the field of water supply, two branches of the economy that are always under pressure
owing to the demand of increasing productivity and that are challenged owing to stricter environmental rules, thus necessitating
promising, low-cost inspection techniques.
The text was submitted by the authors in English. 相似文献
40.
新型阳离子聚丙烯酰胺微粒的研究--含PEO支链阳离子聚丙烯酰胺微粒的合成、助留性能及作用机理 总被引:6,自引:0,他引:6
本文采用反相微乳液聚合的方法合成了丙烯酰胺(AM)/丙烯酰氧基乙基三甲基氯化铵(AD-AMQUAT)/聚氧乙烯大单体(PEO-A)/N,N'-亚甲基双丙烯酰胺(Bis)的四元共聚物微粒.研究了该微粒助留剂的结构与性能.这种微粒和纸纤维能够通过离子键和氢键作用显著地增强助留效果. 相似文献