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811.
812.
四坐标线切割机切丝位置计算 总被引:1,自引:0,他引:1
导出了四坐标线切割机切丝位置计算了一般方法,该算法可以在工件上下表面轮廓为任意空间曲线时,由直纹面的设计数据求出切丝位置。 相似文献
813.
Shi-bin ZHAO Cun-lin ZHANG Nai-ming WU Hua-ming WANG .School of Materials Science Engineering Beihang University Beijing China 《自然科学进展(英文版)》2011,21(4):301-306
Pulsed thermography(PT) as a non-contact non-destructive evaluation(NDE) technique was employed to examine as-sprayed air plasma spray(APS) thermal barrier coatings(TBCs) for quality evaluation.Thickness and micro-structural characteristics play a vital role in determining the quality.In this paper,PT logarithmic peak second-derivative method was adopted to measure the thickness of top coat.Time dependent thermal images were used to characterize the microstructure which was confirmed by scanning electron... 相似文献
814.
This paper considers the distributed estimation of a source parameter using quantized sensor observations in a wireless sensor network with noisy channels. Repetition codes are used to transmit quantization bits of sensor observations and a quasi best linear unbiased estimate is constructed to estimate the source parameter. Simulations show that the estimation scheme achieves a better power and spectral efficiency than the previous scheme. 相似文献
815.
The metal powder direct and rapid prototyping technology is one of the most developing methods in the laser rapid prototyping technique. The coaxial powder delivery system is the key technique. The purpose of this paper is to introduce a new type of coaxial powder delivery system and simulate the metal powder and shield gas flow in the powder nozzle. 2-D and 3-D model of the new coaxial powder delivery system are established. Then gas-solid two-phase flow model and the k-ε turbulent model are selected to simulate the flow of metal powder in powder nozzle. The Euler-Lagrange method is used in the simulating computation. The results show that the new coaxial powder delivery system has stable performance, uniform powder flux, high cooling efficiency, and long useful life. 相似文献
816.
817.
Jie Wen Changsheng Jiang .College of Science Nanjing University of Aeronautics Astronautics Nanjing P.R.China .College of Automation Engineering 《系统工程与电子技术(英文版)》2011,(6):967-974
A robust adaptive fuzzy control scheme is presented for a class of strict-feedback nonaffine nonlinear systems with modeling uncertainties and external disturbances by using a backstepping approach.Fuzzy logic systems are employed to approximate the unknown parts of the desired virtual controls,and the approximation errors of fuzzy systems are only required to be norm-bounded.The function tanh(·) is introduced to avoid problems associated with sgn(·).The tracking error is guaranteed to be uniformly ultimately bounded with the aid of an additional adaptive compensation term.Chua’s circuit system and R o¨ssler system are presented to illustrate the feasibility and effectiveness of the proposed control technique. 相似文献
818.
Study on the photosynthetic performances of Enteromorpha prolifera collected from the surface and bottom of the sea of Qingdao sea area 总被引:1,自引:0,他引:1
LIN APeng WANG Chao QIAO HongJin PAN GuangHua WANG GuangCe SONG LiYun WANG ZhiYuan SUN Song & ZHOU BaiCheng Institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate School Beijing College of Marine Science Engineering Tianjin University of Science & Technology Tianjin 《科学通报(英文版)》2009,(3)
In this work, the photosynthetic performances of Enteromorpha prolifera thalli collected from the sur- face and bottom of the sea of Qingdao sea area were studied with chlorophyll fluorescence and oxy- graph technology. The samples with the highest photosynthetic activity among their kinds, the floating thalli from the sea surface of the south of the Qingdao Olympic Sailing Center and the sedimentary thalli from the mud surface of the bottom Tuandao bay, were chosen as representatives of surface thalli and ... 相似文献
819.
用VRML实现虚拟燕大校园的浏览设计 总被引:2,自引:0,他引:2
VRML是一种崭新的网上虚拟现实技术,在众多应用中,虚拟旅游可以把你带入一个三维世界,实现旅游梦想。一些新技术如光照技术,触发器技术,多媒体技术的采用会使得三维场景更加生动逼真。对虚拟燕大校园的浏览设计到的VRML的相关技术进行了介绍。 相似文献
820.
Search engine is an effective approach to promote the service quality of the World Wide Web. On terms of the analysis of search engines at home and abroad, the developing principle of search engines is given according to the requirement of Web information for chemical fiber engineering. The implementation method for the communication and dynamic refreshment of information on home page of the search engines are elaborated by using programming technology of Active Server Page 3.0 (ASP3.0). The query of chemical fiber information and automatic linking of chemical fiber Web sites can be easily realized by the developed search engine under Internet environment according to users' requirement. 相似文献