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11.
Makoto Hino Minoru Hiramatsu Koichi Akiyama Hitoshi Kawasaki Masato Tsujikawa Makoto Kawamoto 《Materials and Manufacturing Processes》1997,12(1):37-46
A high powered YAG laser with kaleidoscope for surface modification was applied to the surface hardening of carbon steels containing 0. 18-0.54 wt% C without the absorbents, and the relationships between laser processing and surface hardening were investigated by hardness and microstructure. The structure of the hardened zone underwent complete martensitic transformation in all of the carbon steels tested, and its hardness increased with greater carbon content. Under identical irradiated conditions, the hardened zone expanded with increasing carbon content. A hardened zone extending from the surface to a depth of 1.0 mm was obtained at a laser power of 1.0 kW and a scanning speed of 1 mm/sec. It was found that in the surface hardening of carbon steels, a high powered YAG laser can be used to control the hardened zone by selecting the appropriate irradiation conditions, however, the hardened zone was affected by the assistant gas and the flow rate. 相似文献
12.
Makoto Kohga 《含能材料》2006,14(6):471-474
1 IntroductionThe ammonium perchlorate ( AP)-based compositepropellant is currently the most widely used one becausethis propellant has good burning characteristics and me-chanical properties. One of the few serious drawbacks ofthe AP-based propellant is that its products of combus-tion, which include HCl, chlorine, and chlorine oxides,cause atmospheric pollution. Increasing concern for aclean atmosphere in recent years has resulted in a com-pelling need for developing a chlorine-free,enviro… 相似文献
13.
We study dynamics of quantized vortex lattice formation in a rotating Bose-Einstein condensate with a square blue-detuned
optical lattice by solving the Gross-Pitaevskii equation. This dynamics depends on the depth of the optical lattice. Vortices
tend to form a triangular lattice under the rotation, while an optical lattice likes to pin vortices at their peaks. Such
a competition of two effects makes this system more interesting and complicated. 相似文献
14.
In this paper, we describe two kinds of characteristic nonlinear dynamics in two-component Bose–Einstein condensates. For two overlapping components, we analyzed the collective modes and a variety of nonlinear mode couplings, which were then confirmed by numerical simulation of the time-dependent Gross–Pitaevskii equations. Next, we consider the nonlinear dynamics of two condensates after abruptly turning on the intercomponent coupling strength. For strong intercomponent interactions the out-of-phase density wave of the condensates became unstable, leading to mugtiple domain formation. 相似文献
15.
Physical optics (PO) is an approximation method for high‐frequency scattering and diffraction problems. But PO fields are inaccurate in the shadow region where the source is screened by the scatter. Two key factors of the error for PO are (i) edge diffraction coefficients and (ii) existence of fictitious penetrating rays. The correction with respect to the former has been extensively investigated by many authors using various ray techniques such as GTD, UTD, and UAT. On the other hand, the latter was identified recently by the authors. This paper proposes novel PO‐based calculation procedures termed PO‐AF and PTD‐AF, where PO and Aperture Field Integration Method (AFIM) are merged with the help of special elementary diffraction coefficients. These can uniformly cover the whole angular region and only the error factor (ii) is removed in PO‐AF while both (i) and (ii) are removed in PTD‐AF. The theoretical backgrounds of PO currents are discussed in terms of field equivalence theorem and visualization of EM waves. Next, new methods are proposed and their validity is numerically demonstrated for 2D scattering problems of a strip, a corner reflector, and a cylinder of circular arc. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 1–10, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20037 相似文献
16.
Makoto Kasu Rangaiya Rao Susumu Noda Akio Sasaki 《Journal of Electronic Materials》1991,20(9):691-693
Properties of theDX centers in Al0.5Ga0.5As bulk alloy (b-AL), (AlAs)2 (GaSa)2 ordered superlattice (o-SL) and (AlAs)
m
(GaAs)
n
disordered superlattice (d-SL) (m = 1, 2, 3,n = 1, 2, 3) with the same macroscopic composition were measured and compared. By deconvolution of deep level transient spectroscopy
(DLTS) spectrum due to theDX center, we have found a decrease in the number of separate peaks in DLTS spectrum in an intentionally atomic ordered arrangement.
Visiting Scholar of the Japan Society for the Promotion of Science. On leave from Department of Electrical Engineering, San
Jose State University, San Jose, California 95192-0084, USA. 相似文献
17.
Tomoyasu Nakamine Shugo Suzuki Kenji Nakao Makoto Okazaki 《Fullerenes, Nanotubes and Carbon Nanostructures》1995,3(4):389-398
respectively. 相似文献
18.
Makoto Otsuka 《Drug development and industrial pharmacy》1993,19(17):2241-2269
The effects of temperature on the polymorphic transformation and the compression of chlorpropamlde forms A and C during tabletting were investigated by X-ray diffractometry. The X-ray diffraction profiles of the sample powders deagglomerated after compression were recorded to calculate the degree of polymorphic transformation. A single punch eccentric tabletting machine equipped with two load cells (upper and lower punches) and with a noncontact displacement transducer was used to measure the compression stress, energy and distance between punches. A heater and a liquid nitrogen pool were mounted on the die of the tabletting machine, and the die temperature was controlled with a thermocontroller. Two types of compression methods, multi-tabletting at room temperature and single tabletting at 0-45°C, were used in the present study. In the first method, the stable form A or metastable form C was loaded in to the die and the sample was compressed with a compression stress of 196 MPa. Compression was repeated from 1 to 30 times. The results for forms A and C suggested that both forms were mutually transformed, and that the content of forms A and C reached equilibrium above 100 J/g of compression energy after more than 10-times compression. After 30-times compression, the content of A, C, and the noncrystalline solid form were almost constant at about 45%, 25% and 30%, respectively. The compression energy was estimated to be 500-600 J/g. In the second method, single tabletting at 0° and 45°C, the amount of form C transformed from form A at 45°C was about two times larger than that at 0°C at the same compression energy. The amount of form A transformed from form C at 45°C was almost the same as that transformed at 0°C. This suggests that the mechanochemical stability of form A was affected by compression temperature, while that of form C was independent of temperature. The crushing strength (CS) of from A tablet was about two times higher than that of form C even at the same porosity. The relationships between log (CS) of form A tablets compressed at 0 or 45°C and porosity showed straight lines with the same slope, but the slope for form C tablets compressed at 45°C was smaller than that for those compression at 0°C. From these results it appears that the transformation mechanism of forms A and C during compression was as follows: Form A or C was converted to a noncrystalline solid by mechanical energy, and then the solid was transformed into form A or C. The transformation of every form was affected by the environmental temperature. 相似文献
19.
Temperature dependences of the soft phonon frequency and the damping constant in Tris-Sarcosine Calcium Chloride (TSCC) single crystal have been investigated between 5K and 100K by using a Fourier-transform far-infrared spectrometer. It has been observed that the soft phonon frequency decreases gradually and the damping constant increases as the transition temperature is approached from below The damping constant varies from 7cm-1 a 90K to less than 0.5cm-1 at 5K. It has been found that the damping constant is approximately proportional to temperature below about 60K. 相似文献
20.
Makoto Iida Masao Gotoh Hitoshi Yokono Yasushi Miyano 《Polymer Engineering and Science》1986,26(10):701-707
Flexural properties of moldings made by Reaction Injection Molding (RIM), which are structural foams consisting of high density skin and low density core, were investigated by three-point bending tests. Two failure modes were observed in bending tests of the moldings made by RIM, and they are classified as follows according to the density ratio of skin layer to core layer: the opposite side of the skin layer to which load was subjected failed by tensile stress: and the same side of the skin layer to which load was subjected failed by compressive stress, causing wrinkling or buckling. Then the conventional composite beam theory was applied to the former failure mode and Hoff s buckling theory to the latter, and equations were derived to predict the flexural properties of the structural foams, which involved buckling from the flexural properties of solid construction. In addition, it has been shown that there exists a density distribution that maximizes the flexural strength of the moldings made by RIM with a given overall density. The results obtained here should be useful to the optimum structural design of moldings made by RIM. 相似文献