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51.
Crack propagation velocity in delayed failure under superposed repeating load, (, was compared with that under static load, (Two peaks appear on the relation between decreasing rate of crack propagation velocity, and frequency, ?, both under sinusoidal and square load. By changing the ratio of holding time at maximum stress intensity factor to that at minimum stress intensity factor in square load, it was deduced that the existence of two peaks on the 1 ? β vs curve was caused by an asymmetric interaction between hydrogen atoms and cyclic moving of the position with triaxial tensile stress at crack tip. Moreover, the relation between 1 ? β and under the positive or negative saw tooth load could be well explained by the interaction model. 相似文献
52.
Nyquist RM Ataka K Heberle J 《Chembiochem : a European journal of chemical biology》2004,5(4):431-436
The catalytic action of membrane proteins is vital to many cellular processes. Yet the molecular mechanisms remain poorly understood. We describe here the technique of evanescent infrared difference spectroscopy as a tool to decipher the structural changes associated with the enzymatic action of membrane proteins. Functional changes as minute as the protonation state of individual amino acid side chains can be observed and linked to interactions with a ligand, agonist, effector, or redox partner. 相似文献
53.
We have developed a new analytical transmission electron microscope (TEM), called coincidence TEM, which, in principle, enables observation of elemental mapping images at a high signal-to-noise ratio. We have previously reported the successful observation of an elemental mapping image of a specimen, but over a very long period of time (168 h). To solve this inefficiency, we installed a gamma-type imaging energy filter in the coincidence TEM to remove the no-loss electrons, which are mainly transmitted electrons. This has enabled the intensity of the background signals in the coincidence measurement to be markedly reduced. The coincidence TEM with a gamma-type imaging energy filter allows the coincidence image to be observed in 3 h, thus, the measurement time is shortened by two orders of magnitude. Moreover, the use of a silicon drift detector (SDD) will shorten the measurement time. 相似文献
54.
Taiji?Sugiyama Noriyasu?Homma Kenichi?Abe Masao?SakaiEmail author 《Artificial Life and Robotics》2004,7(4):156-159
We have developed a novel pulse-coupled neural network (PCNN) for speech recognition. One of the advantages of the PCNN is
in its biologically based neural dynamic structure using feedback connections. To recall the memorized pattern, a radial basis
function (RBF) is incorporated into the proposed PCNN. Simulation results show that the PCNN with a RBF can be useful for
phoneme recognition.
This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18,
2002 相似文献
55.
Kojima K Hiratsuka A Suzuki H Yano K Ikebukuro K Karube I 《Analytical chemistry》2003,75(5):1116-1122
An electrochemical protein chip was microfabricated. A thin-film three-electrode system, including an array of 36 platinum working electrodes, a set of thin-film Ag/AgCl electrodes, and platinum auxiliary electrodes, was integrated on a glass substrate. Capture antibodies were immobilized in a 4.5-nm-thick double layer of a hexamethyldisiloxane plasma-polymerized film. Because of their highly cross-linked network structure, the capture antibodies could be firmly immobilized. No nonspecific adsorption was observed during a series of procedures to detect target proteins, and electrochemical cross talk between neighboring sites was negligible. The sandwich immunoassay was conducted on a single chip using model proteins, alpha-1-fetoprotein and beta2-microglobulin. A distinct current increase following the oxidation of hydrogen peroxide produced by the enzymatic reaction of glucose oxidase was observed, which indicates that the capture proteins could actually bind the target proteins. Two kinds of protein were detected independently on multiple sites with respective capture antibodies. 相似文献
56.
There is increasing demand for in situ shape measurements performed on ultraprecision processing machines. One major source of error during interferometric measurements performed on machines is fringe displacement due to external disturbances. We have developed an interferometer equipped with an electro-optic phase modulator that measures the phase of interference fringes before they are displaced by air turbulence. The frequency characteristics of air turbulence induced by a heat source are derived from successive measurements of a test surface. Experimental results show that the phase of the interference fringes can be accurately measured in the presence of air turbulence when the intensity of the fringes is sampled at a speed of several hundred hertz. 相似文献
57.
We study theoretically the generation of cyclic supercurrent among three superfluids coupled by the Josephson Junctions. Depending on the initial relative phases between superfluids, Josephson current flows cyclically through the superfluids to create a quantized vortex. Reducing the coupling strength changes the motion from periodic to chaotic, thus suppressing the cyclic current. Applying this result to the Kibble-Zurek mechanism, the probability of the vortex generation via this mechanism is modified from the simple estimate given by the geodesic rule. We compare our results with the Lancaster, Grenoble and Helsinki experiments. 相似文献
58.
Kenichi Kasamatsu Yukinori Yasui Makoto Tsubota 《Journal of Low Temperature Physics》2002,126(1-2):437-442
We show theoretically the existence of the metastable state and study the decay through the macroscopic quantum tunneling in two-component Bose-Einstein condensates. The numerical analysis of the coupled Gross-Pitaevskii equations clarifies the metastable states whose configuration preserves or breaks the symmetry of the trapping potential, depending on the interspecies interaction and the particle number. We calculate the tunneling decay rate of the metastable state by using the collective coordinate approximation and the bounce technique. It is found that the macroscopic quantum tunneling is observable in a wide range of the particle number. 相似文献
59.
Linear programming is one of the most widely used Operations Research/Management Science techniques. Recently, multiple objective decision making has been well established as a practical approach to seek a satisfactory solution to a decision making problem. Much attention has been focused on a microcomputer as an economical management tool.
In this paper we propose an interactive goal attainment method using the eigenvector algorithm for solving a multiple objective linear programming problem interactively on microcomputers. In the software package Micro-LPS based on the method proposed, we design a conversational and user-friendly system in which the user commands are involved. 相似文献
60.
Chiral poly[4,6-bis(alkylthio)-1,3-phenylene-alt-2-methyl-1,3-phenylene] was synthesized from 1,3-dibromo-2,6-bis(3-dodecyl-2-methylthio)benzene and 2-methyl-1,3-phenylenebis(pinacol borate) as a precursor of chiral poly(thiaheterohelicene). Circular dichroism (CD) spectra that arise from the poly(1,3-phenylene) backbone inverted according to the chirality of the side chains, which indicated that a helical conformation of the polymer was induced by the interaction between the side chains. The CD intensity of the polymer increased in non-polar solvents such as hexane. The decrease in the molar CD intensity and the broadening of a fluorescence band at higher concentrations suggested that the aggregation of the polymer suppressed the formation of the helical structure. The conformational changes were monitored by the CD and the 1H NMR spectra at different temperatures. In a good solvent such as dichloromethane, the CD intensity increased, and the 1H NMR signal of benzene protons shifted to lower fields at low temperatures. In hexane, the CD spectra and the 1H NMR signals were less dependent on temperatures, as a result of the strong interaction between the chiral alkyl chains in the polymer to freeze the helical conformation. 相似文献