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排序方式: 共有395条查询结果,搜索用时 15 毫秒
1.
A micromechanics model is proposed to analyse residual stresses and deformations that develop in short-fibre composites upon an applied uniform temperature change. The model is based on Eshelby's equivalent inclusion method and treats the interaction among fibres at finite volume fractions through the Mori-Tanaka mean field theory. The model treats the matrix as an elastic/plastic material while the fibre is elastic and is able to account for the effects of the composite microgeometry. To this end, the effects of misoriented short fibres, the orientation of which is described by a density distribution function, are considered. Numerical results obtained from the proposed model indicate that the misorientation of short fibres has a significant effect on both the stress and deformation behaviour of short-fibre composites. 相似文献
2.
Masahito Matsubayashi Takashi Hibiki Kaichiro Mishima Koji Yoshii Koji Okamoto 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2003,510(3):325-333
A fluorescent converter for fast neutron radiography (FNR) comprising a scintillator and hydrogen-rich resin has been developed and applied to electronic imaging. The rate of the reaction between fast neutrons and the converter is increased by thickening the converter, but its opaqueness attenuates emitted light photons before they reach its surface. To improve the luminosity of a fluorescent converter for FNR, a novel type of converter was designed in which wavelength-shifting fibers were adopted to transport radiated light to the observation end face. The performance of the converter was compared with that of a polypropylene-based fluorescent converter in an experiment conducted at the fast-neutron-source reactor YAYOI in the University of Tokyo. 相似文献
3.
Tsuyoshi Takahashi Masahito Kitou Michio Asai Mitsuyasu Kido Tomio Chiba Junzou Kawakami Yoshiaki Matsui 《Electrical Engineering in Japan》1994,114(2):18-33
Power system control equipment needs higher sensitivity and operational reliability. Advanced voltage control equipment is needed for reducing the frequency of tap changes and improving the characteristics (the relationship between the actual voltage and reference voltage) of the voltage to meet today's power system requirements. However, these objectives are in a trade-off relationship. Studies of voltage control derived from a knowledge base suitable for electric power systems can satisfy these objectives using fuzzy inference. Compared with corresponding conventional equipment, the new equipment improved the deviation of 30 min average voltage of 30 percent. This paper describes the design concept of new voltage control equipment using fuzzy inference. In addition, field test results are described along with rules of fuzzy inference, membership functions, and the deviation of 30 min average voltage through detailed simulation. 相似文献
4.
Sun-Chan Jeong Ichiro Katayama Hirokane Kawakami Yutaka Watanabe Hironobu Ishiyama Nobuaki Imai Yoshikazu Hirayama Hiroari Miyatake Masao Sataka Satoru Okayasu Hiroyuki Sugai Shin-Ichi Ichikawa Katsuhisa Nishio Shinichi Mitsuoka Takamitsu Nakanoya Masahito Yahagi Takanori Hashimoto Kazunori Takada Mamoru Watanabe Tomoko Ishikawa Akihiro Iwase 《Journal of Phase Equilibria and Diffusion》2005,26(5):472-476
For the effective use of short-lived radioactive beams, soon to be available at the Tokai Radioactive Ion Accelerator Complex, the authors have developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound βLiAl using an α-emitting radiotracer of 8Li (T1/2=0.84 s). It was found that the time-dependent yields of the α particles from the diffusing 8Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in βLiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects (i.e., the existence of the atomic vacancies of Li and the defects in Ga sites that are replaced by Li). 相似文献
5.
Atsushi Kameda Masahito Yamamoto Azuma Ohuchi Satsuki Yaegashi Masami Hagiya 《Natural computing》2008,7(2):287-298
DNA machines consisting of consecutive hairpins, which we have previously described, have various potential applications in
DNA computation. In the present study, a 288-base DNA machine containing four consecutive hairpins was successfully constructed
by ligation and PCR. PAGE and fluorescence spectroscopy experiments verified that all four hairpins were successfully opened
by four opener oligomers, and that hairpin opening was dependent on the proper openers added in the correct order. Quantitative
analysis of the final results by fluorescence spectroscopy indicated that all four hairpins were open in about 1/4 to 1/3
of the DNA machines. 相似文献
6.
Mitsuyoshi Nagao Masahito Yamamoto Keiji Suzuki & Azuma Ohuchi 《International Transactions in Operational Research》2001,8(1):31-45
In this paper, we propose a face identification system based on the Mahalanobis–Taguchi System (MTS). The MTS is one of the pattern recognition methods frequently used in quality engineering, and can perform robust pattern recognition by using training data, including noise. It is likely that this advantage will allow the effective implementation of a robust face identification system against lighting and face position fluctuations. Moreover, the MTS can optimize the number of attributes required for identification by using the orthogonal array and the signal/noise (SN) ratio. The face identification system has to deal with many users and the amount of data in a facial image is large. Therefore, the time required for identification can be decreased and the amount of data in the facial image database can be reduced by performing the optimization. We confirmed the effectiveness of the proposed system through practical experiments. The experimental results revealed that the MTS was an effective method for robust face identification, and could effectively reduce the number of attributes required for identification. 相似文献
7.
ABSTRACTA cognitive map is an internal model of the external world and contains the spatial representation of the surrounding environment. The existence of the cognitive map was first identified in rats; rats can navigate to their desired destination using cognitive maps while dealing with environmental uncertainty. We performed a mobile robot navigation experiment where obstacles were randomly placed using hierarchical recurrent neural network (HRNN) with multiple timescales. The HRNN was trained to navigate the mobile robot to the destination indicated by a snapshot image. After the training, the HRNN was able to successfully avoid the obstacles and navigate to the destination from any location in the environment. Analysis of the internal states of the HRNN showed that the module with fast timescale handles obstacle avoidance and the one with slow timescale has spatial representation corresponding to the spatial position of the destination. Moreover, in the experiment wherein the novel path appeared, the trained HRNN performed shortcut behavior. The shortcut behavior shows that the HRNN performed navigation using the self-organized spatial representation in the slow recurrent neural network. This indicates that training of goal-oriented navigation, i.e. the navigation motivated by a snapshot image of the destination results in the self-organization of cognitive map-like representation. 相似文献
8.
Slider Dynamics over a Discrete Track Medium with Servo Patterns 总被引:1,自引:0,他引:1
The dynamic characteristics of a slider flying over various servo patterns on a discrete track medium surface were investigated.
The investigation shows that the air-flow field is disturbed and causes flying amplitude during the transition from grooved
longitudinal discrete tracks to a transversal and near-random pattern in the servo field. The effects of the parameters that
define the servo pattern including land-area ratio of burst patterns, groove depth, servo-pattern frequency, and the lengths
of synchronization (sync), servo address mark (SAM), padding (PAD) blocks, and burst pattern type—on the flying height responses
were evaluated. The evaluation results indicate that the flying height amplitude depends on servo-pattern frequency, burst
land-area ratio, groove depth, and the lengths of the sync, SAM, and PAD block and burst pattern type. Amplitude of a slider
flying over a servo pattern therefore can be reduced by optimizing the servo-pattern design from the viewpoint of these parameters.
Moreover, flying-height responses over servo patterns with thermal flying height control (TFC) power were studied and compared
with those without TFC power. 相似文献
9.
Shigetaka Okano Kazunori Matsushita Masahito Mochizuki Masao Toyoda Tomoyuki Ueyama 《Welding International》2013,27(4):289-300
It is well known that weld residual stress and distortion should be controlled appropriately for structural integrity. Recently, it has become much more necessary to control weld distortion to highly improve manufacturing efficiency. Various studies on control of weld distortion had been conducted based on clarification of influential dominant factors for that. The influential dominant factors had been studied from a viewpoint of temperature distribution in plate thickness section. Without considering moving the weld heat source, the temperature distribution is controlled by weld heat input (Qnet) per weld length. Angular distortion, which is controlled by temperature distribution along the direction of plate thickness (h), is controlled by heat input parameter (Qnet/h2). However, it has recently become known that the conventional results cannot be applied to all welding processes because such processes are becoming more diversified. It is significant for more accurate control of angular distortion to investigate once again the relationship between the heat input parameter and angular distortion. In this study, a series of experiments on the relationship between heat input parameter and angular distortion are carried out. The effects of welding current and welding speed are investigated individually in both TIG and MAG welding. The difference between these welding methods is also investigated. Based on the result, the effects of them are discussed in relation to temperature distribution during welding. It is considered that angular distortion is affected by temperature distribution not only in plate thickness section but also along welding direction. So, angular distortion is not always controlled by only the conventional heat input parameter because the heat input parameter is proposed as the influential dominant factor for temperature distribution in plate thickness section. It is concluded that generation characteristics of inherent strain should be considered in relation to three-dimensional temperature distributions during welding for more accurate control of angular distortion. 相似文献
10.
Yuki Kotani Shigetaka Okano Shinji Kobayashi Tadahisa Tsuyama Masahito Mochizuki 《Welding International》2016,30(11):826-834
Reduction or control of angular distortion without additional processes is demanded because it takes a lot of time and effort to correct the angular distortion of fillet-welded T-joints. In this study, the reduction or control of angular distortion of both sides of a fillet-welded T-joint by welding with trailing reverse-side gas heating was investigated through a welding experiment and its numerical simulation. First, the effect of gas heating position and intensity on the reduction in angular distortion was experimentally investigated using a gas burner. The results showed that angular distortion became smallest when reverse-side heating using the gas burner was located 50 mm backward of the welding torch. Also, the concentrated gas flame with increased propane and oxygen gas flow was effective for reducing angular distortion. It was clarified that the angular distortion could be controlled completely with an appropriate reverse-side gas heating condition. Next, the numerical simulation model of welding and gas heating was constructed based on comparison with the measured temperature histories and angular distortion. Through the numerical simulation of welding with a trailing reverse-side gas, more detailed understanding of the effect of gas heating condition on reduction in angular distortion was developed. In addition, it was confirmed that the gas heating position for the smallest angular distortion is dependent on the temperature distribution along the thickness of the flange plate. 相似文献