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51.
In this paper we analyse the vibrations of an N-stepped Rayleigh bar with sections of complex geometry, supported by end lumped masses and springs. Equations of motion and boundary conditions are derived from the Hamilton’s variational principal. The solutions for tapered and exponential sections are given. Two types of orthogonality for the eigenfunctions are obtained. The analytic solution to the N-stepped Rayleigh model is constructed in terms of Green function. 相似文献
52.
介绍了FAST公司研制推广使用的企业搜索技术、相关搜索技术及其在不同企业的应用。FASTESP向用户安全提供了结构、非结构与多媒体数据检索点.为新的智能检索建立新的标准。所具备的上下文识别、可测量性和制订解决方案的超级性能极大程度地改变着公司从事贸易的活动方式,同时也改变了用户的搜索信息方式。 相似文献
53.
Lin Yikun Luo Xizhang Qiu Bingzheng Pang Xiao 《International Journal of Infrared and Millimeter Waves》1989,10(12):1427-1440
The optimum operating parameters of miniature OPFIRL was studied theoretically and experimentally. The theoretical results were in pretty good agreement with experimental results except for 1.5cm laser. The transverse feedback effect plays an important role in the miniature OPFIRL. it's worthv to be funther studied. 相似文献
54.
Solvothermal synthesis of CdS nanowires using L-cysteine as sulfur source and their characterization
Hongde Gai Youshi Wu Lili Wu Zhigang Wang Yuanchang Shi Min Jing Ke Zou 《Applied Physics A: Materials Science & Processing》2008,91(1):69-72
An effective solvothermal reaction route has been developed for large-scale synthesis of CdS nanowires. L-cysteine was used
as both sulfur source and capping reagent. The nanowires obtained were characterized by XRD, SEM, TEM, HRTEM, UV-Vis and PL.
On the basis of time-resolved experiments, a possible growth mechanism was proposed. FTIR analysis confirmed the formation
of Cd-cysteine complex and peptide during the reaction. The mechanism was further supported by comparative experiments with
other sulfur sources.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.
PACS 81.05.Bx; 81.07.-b; 81.07.BC; 81.07.Vb; 81.10.Dn 相似文献
55.
The degradation of azobenzene (AO) by a gaseous plasma is reported. The plasma was generated in a localized zone between an electrolytic solution and a tip of an anode in contact with the surface of solution by means of contact glow discharge electrolysis. There is an optimum pH for the degradation of AO. Iron (II) had a remarkable catalytic action on it. Furthermore, the degradation followed the first‐order kinetic law. Some of the intermediate products of the degradation process were detected by HPLC. 相似文献
56.
中文文本压缩的LZW算法 总被引:8,自引:0,他引:8
本文报告两个关于中文信息处理研究的结果:(1)采用Cover的方法,猜估中文信息熵,实验表明,中文信良熵不大于4.1bits/字。(2)根据中文的结构特性,选择Welch型的Lemple-Ziv数据压缩算法,把它移植、扩展于中文文本压缩上。应用该算法于不同类型的中文文本,本文获得一些中文文本压缩实际性能值。 相似文献
57.
58.
<正>Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time, and its performance was carefully characterized.Due to the specific recognition of tetracycline by the particles,the selectivity coefficients for routine interferences were less than 10~(-4).Benefited from the absence of tetracycline in the sensitive membrane and the optimized composition of the inner filling solution,the limit of detection of the electrode was reduced to about 2.5×10~(-8) mol/ L.It exhibited a good electrode slope 57.6 mV/decade near the theoretical Nernstian one,with a wide linear working range from 6.0×10~(-8) to 1.0×10~(-3) mol/L.The fabricated electrode should be used in pH 2-4,response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0×10~(-6) mol/L and no more than 30 min at the concentration of 1.0×10~(-8) mol/L. 相似文献
59.
Generation of short-wavelength radiation by a free-electron laser using up-frequency conversion of an electron bunch density modulation is currently an area of active research. We propose a new scheme for producing the longitudinal electron bunch density modulation similar to the recently proposed echo-enabled harmonic generation but based on an emittance exchange beam line and a multislit mask. Beam line analysis and start-to-end simulation are presented. 相似文献
60.
In strongly correlated electronic systems, the global transport behavior depends sensitively on spin ordering. We show that spin ordering in manganites can be controlled by depositing isolated ferromagnetic nanodots at the surface. The exchange field at the interface is tunable with nanodot density and makes it possible to overcome dimensionality and strain effects in frustrated systems to greatly increasing the metal-insulator transition and magnetoresistance. These findings indicate that electronic phase separation can be controlled by the presence of magnetic nanodots. 相似文献