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131.
132.
This research focuses on the fabrication of glass fiber/epoxy nanocomposites containing organoclay as well as understanding the organoclay effect on the transverse compressive strength of nanocomposites. To demonstrate the organoclay effect, three different loadings of organoclay were dispersed, respectively, in the epoxy resin using a mechanical mixer followed by sonication. The corresponding glass/epoxy nanocomposites were produced by impregnating dry glass fiber with organoclay epoxy compound through a vacuum hand lay-up procedure. Unidirectional block specimens were employed for transverse compression tests on a hydraulic MTS machine. Experimental observations indicate that glass/epoxy nanocomposites containing organoclay exhibit higher transverse compressive strength than conventional composites. Furthermore, the failure mechanisms for all tested specimens were found to be fiber and matrix debonding. Therefore, results indicate that the increasing characteristic in transverse failure stress may be ascribed to the enhanced fiber/matrix adhesion modified by the organoclay. 相似文献
133.
Jeng-Han Tsai Wei-Chien Chen To-Po Wang Tian-Wei Huang Huei Wang 《Microwave and Wireless Components Letters, IEEE》2006,16(6):327-329
A miniature Q-band low noise amplifier (LNA) using 0.13-/spl mu/m standard mixed signal/radio frequency complementary metal-oxide-semiconductor (CMOS) technology is presented in this letter. This three-stage common source thin-film microstrip LNA achieves a peak gain of 20dB at 43GHz with a compact chip size of 0.525mm/sup 2/. The 3-dB frequency bandwidth ranges from 34 to 44GHz and the minimum noise figure is 6.3dB at 41GHz. The LNA outperforms all the reported commercial standard CMOS Q-band LNAs, with the highest gain, highest output IP3, and smallest chip size. 相似文献
134.
Fu S.-I. Cheng S.-Y. Chen T.-P. Lai P.-H. Tsai Y.-Y. Hung C.-W. Yen C.-H. Liu W.-C. 《Electron Devices, IEEE Transactions on》2006,53(11):2689-2695
A comprehensive study of emitter-ledge thickness of InGaP/GaAs heterojunction bipolar transistors (HBTs) has been undertaken. It is shown that the recombination rate and electron densities are drastically increased near the exposed base surface between the base contact and the emitter ledge. In contrast, the corresponding hole densities are decreased. If the emitter ledge is too thick, current will flow through the undepleted ledge, which increases the emitter-size effect. In contrast, if the emitter ledge is too thin, it may not effectively passivate the surface. Therefore, the thickness of the emitter ledge is a crucial issue and should be carefully considered. It is shown that, from simulated and experimental results, the optimum emitter-ledge thickness of InGaP/GaAs HBT is 100-200 Aring 相似文献
135.
Tai-Wen Hsu Yuan-Jyh Lan Yung-Her Wang Chin-Yen Tsai 《Canadian Metallurgical Quarterly》2005,131(11):1214-1217
In this study, a finite element method proposed by Hsu et al. in 2003 is extended to develop a numerical model for the simulation of wave transformation in the surf zone. The governing equation is the elliptic mild-slope equation including the energy dissipation of wave breaking. At the open boundaries with varying depth, the reflected waves caused by shoaling are adopted to the radiation boundary conditions. The rationality of the present numerical model is examined through the cases of offshore parallel breakwater problems. The results of calculation are in good agreement with experimental results. 相似文献
136.
The constrained longest common subsequence problem 总被引:1,自引:0,他引:1
Yin-Te Tsai 《Information Processing Letters》2003,88(4):173-176
This paper considers a constrained version of longest common subsequence problem for two strings. Given strings S1, S2 and P, the constrained longest common subsequence problem for S1 and S2 with respect to P is to find a longest common subsequence lcs of S1 and S2 such that P is a subsequence of this lcs. An O(rn2m2) time algorithm based upon the dynamic programming technique is proposed for this new problem, where n, m and r are lengths of S1, S2 and P, respectively. 相似文献
137.
An interactive agent-based system for concept-based web search 总被引:1,自引:0,他引:1
Search engines are useful tools in looking for information from the Internet. However, due to the difficulties of specifying appropriate queries and the problems of keyword-based similarity ranking presently encountered by search engines, general users are still not satisfied with the results retrieved. To remedy the above difficulties and problems, in this paper we present a multi-agent framework in which an interactive approach is proposed to iteratively collect a user's feedback from the pages he has identified. By analyzing the pages gathered, the system can then gradually formulate queries to efficiently describe the content a user is looking for. In our framework, the evolution strategies are employed to evolve critical feature words for concept modeling in query formulation. The experimental results show that the framework developed is efficient and useful to enhance the quality of web search, and the concept-based semantic search can thus be achieved. 相似文献
138.
In this paper, we shall discuss oscillatory behavior of the solutions of difference equations, including the self-adjoint second-order linear equation and the discrete version of the nonlinear wave equation. Our work is to give sufficient conditions such that every nontrivial solution of the equations oscillates. 相似文献
139.
Provided with plenty of data (experience), data mining techniques are widely used to extract suitable management skills from the data. Nevertheless, in the early stages of a manufacturing system, only rare data can be obtained, and built scheduling knowledge is usually fragile. Using small data sets, this research's purpose is improving the accuracy of machine learning for flexible manufacturing system (FMS) scheduling. The study develops a data trend estimation technique and combines it with mega-fuzzification and adaptive-network-based fuzzy inference systems (ANFIS). The results of the simulated FMS scheduling problem indicate that learning accuracy can be significantly improved using the proposed method involving a very small data set. 相似文献
140.
Chuan Pu Sangtae Park Chu P.B. Shi-Sheng Lee Ming Tsai Peale D. Bonadeo N.H. Brener I. 《IEEE journal of selected topics in quantum electronics》2004,10(3):472-477
We propose and demonstrate electrostatic sidewall-electrodes actuation of three-dimensional (3-D) microelectromechanical systems (MEMS) gimbal mirrors. The linearity of the mirror angle dependence on actuation voltage is improved with the sidewall-electrodes actuation. In addition, the undesired spring-softening effect commonly found in electrostatic actuation, where the mirror resonance frequency decreases with increased tilt angle, is significantly reduced. Sidewall actuation enables superior performance of 3-D MEMS mirrors including large pull-in angles, reduced actuation voltages, improved device reliability, and fast switching times. 相似文献