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排序方式: 共有620条查询结果,搜索用时 15 毫秒
11.
Core machining is often applied to improve the formativeness of foam core and the manufacturing effectiveness of sandwich panels. This paper investigates the effects of core machining configuration on the interfacial debonding toughness of foam core sandwich panels fabricated by vacuum-assisted resin transfer molding process. Several machining configurations are conducted to foam core, and skin–core debonding toughness of fabricated sandwich panels is evaluated using double-cantilever-beam tests. The sandwich panels with core cuts exhibited higher apparent fracture toughness than the panels without core cut, specifically in the case of perforated core. The relationship between core machining configuration and measured fracture toughness is discussed based on the experimental observations and the numerical analyses of energy release rates. 相似文献
12.
Chuzo Iwamoto Naoki Hatayama Yoshiaki Nakashiba Kenichi Morita Katsunobu Imai 《Acta Informatica》2007,44(5):345-359
We present translational lemmas for the three standard models of parallel computation, and apply them to obtain tight hierarchy
results. It is shown that, for arbitrarily small rational constant , (i) there is a language which can be accepted by a -uniform circuit family of depth and size but not by any -uniform circuit family of depth and size , (ii) there is a language which can be accepted by a -time -space ATM with l worktapes but not by any -time -space ATM with the same l worktapes if the number of tape symbols is fixed, and (iii) there is a language which can be accepted by a -time PRAM with processors but not by any -time PRAM with processors. Here, c > 0, d ≥ 1, r
1 > 1, and r
2 ≥ 1 are arbitrary rational constants, and l ≥ 2 is an arbitrary integer.
Preliminary versions of different parts of this paper appeared in Proc. MCU 2004 (LNCS 3354) and Proc. FCT 2005 (LNCS 3623). 相似文献
13.
FA Jakobiec SL Trokel D Aron-Rosa T Iwamoto D Doyon 《Canadian Metallurgical Quarterly》1980,98(10):1814-1820
Four patients (aged 5, 8, 14, and 51 years at initial manifestation) with isolated eosinophilic granulomas of the orbital frontal bone displayed short symptomatic periods (two weeks to three months) and some combination of erythema of the lids, a soft, palpable anterior orbital mass, periorbital pain, and osteolytic bone lesions on roentgenography. The bone lesions roentgenographically exhibited irregular, serrated, and sclerotic margins, distinguishing them from the more oval appearance of dermoid cysts. Electron microscopy performed in one case disclosed the presence of Langerhans' granules in the cytoplasm of the histiocytes, indicating that the orbital disease is a mild form of "histiocytosis X" and a benign proliferation of a specific kind of histiocyte--the Langerhans' cell. On follow-up (two to 20 years), after incomplete curettage of two lesions coupled with low doses of postoperative radiotherapy, there was reconstitution of the bone defects, whereas more extensive surgery performed on the other two patients resulted in permanent but subclinical bone defects. 相似文献
14.
Toshikazu Fujino Katsumi Iwamoto Kentaro Tanaka Masayuki Shima 《Tribology International》2007,40(10-12):1638
In recent years, the techniques improving sliding performances have progressed by using coated films possessing superior tribological properties, to reduce the failures of the mechanical elements. Those techniques are often used under severe conditions such as elastohydrodynamic lubrication (EHL). In this paper, numerical three-dimensional analysis of the maximum shear stress applied into the coated film and substrate under a single EHL operating condition was performed with a range of coated film thickness and elastic properties. The strength of coated film as one of those techniques was evaluated numerically, resulting in an optimum design of coated film. As a result, coated films with a larger value of thickness and a smaller modulus of elasticity than that of substrate are preferable. 相似文献
15.
Fukuzawa M. Iwamoto A.M. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2001,8(5):832-837
Surface potentials of polyimide (PI) Langmuir-Blodgett (LB) films on metal (Al, Ag and Au) electrodes, charged at various voltages, were examined under a needle-plane electrode system. It was found that PI LB films were negatively charged when the biasing voltage applied to the needle-electrode increased. The surface potentials saturated when the number of deposited layers was 20 to 30, and they were dependent on the nature of the metal electrodes. The temperature dependence of the surface potential also was examined, and it was concluded that the tendency to accept electrons increases as the temperature increases. These results suggest that the presence of interfacial electrostatic space charges in as-deposited PI LB films at the metal/film interface made a significant contribution to the creation of the additional electrostatic potential when the films were biased under a needle-plane electrode system 相似文献
16.
The alkyl derivatives of boehmite were prepared by solvothermal reaction of aluminum isopropoxide in n-alcohols (ethanol, 1-butanol, 1-hexanol, 1-octanol and 1-dodecanol) and the products were recovered as aerogel/xerogel by
the removal of the solvent at the end of reaction. Aerogel or xerogel can be obtained simply by using only a reaction vessel
(autoclave) and the obtained products were composed of plate-like particles having a well-developed boehmite structure. The
alumina powders obtained by calcination of these products had relatively large pore-volumes ranging from 1.35 to 2.56 cm3/g. Transformation into α-Al2O3 was retarded even after calcination at 1200 °C. The effect of n-alcohols used in the solvothermal reaction on the phase, morphology and pore-texture of the alumina samples are discussed. 相似文献
17.
Kyeong-Ho Yeon Heesu Park Seung-Hak Lee Yong-Min Park Sang-Hyup Lee Masakazu Iwamoto 《Korean Journal of Chemical Engineering》2008,25(5):1040-1046
Eutrophication caused by the excessive supply of phosphate to water bodies has been considered as one of the most important
environmental problems. In this study, the powder of zirconium mesostructure (ZM), which was prepared with the template of
surfactant, was immobilized in calcium alginate for practical application and the resulting material was tested to evaluate
the phosphate removal efficiency. Sorption isotherms and kinetic parameters were obtained by using the entrapped ZM beads
with 30 to 60% of ZM. The maximum sorption capacity increased with the higher ZM content. Q
max
in Langmuir isotherm was 51.74 mg/g for 60% of ZM with 7 mm of size. The smaller the particle size of the ZM beads, the faster
the rate of phosphate removal, because the phosphate ions had less distance to reach the internal pores of the immobilized
ZM beads. Chemical and electrochemical regeneration techniques were compared. Phosphates adsorbed on the ZM beads were effectively
desorbed with NaCl, NaOH, and Na2SO4 solutions. An electrochemical regeneration system consisting of an anion exchange membrane between two platinum-coated titanium
electrodes was successfully used to desorb and regenerate the phosphate-saturated ZM beads. Complete regeneration was reached
under optimal experimental conditions. Chemical and electrochemical regeneration proved the reusability of the bead form of
the entrapped ZM, and will enhance the economical performance of the phosphate treatment process. 相似文献
18.
Hiroki Iwamoto Alexey Stankovskiy Luca Fiorito Gert Van den Eynde 《Journal of Nuclear Science and Technology》2018,55(5):539-547
The applicability of Monte Carlo techniques, namely the Monte Carlo sensitivity method and the random-sampling method, for uncertainty quantification of the effective delayed neutron fraction βeff is investigated using the continuous-energy Monte Carlo transport code, MCNP, from the perspective of statistical convergence issues. This study focuses on the nuclear data as one of the major sources of βeff uncertainty. For validation of the calculated βeff, a critical configuration of the VENUS-F zero-power reactor was used. It is demonstrated that Chiba's modified k-ratio method is superior to Bretscher's prompt k-ratio method in terms of reducing the statistical uncertainty in calculating not only βeff but also its sensitivities and the uncertainty due to nuclear data. From this result and a comparison of uncertainties obtained by the Monte Carlo sensitivity method and the random-sampling method, it is shown that the Monte Carlo sensitivity method using Chiba's modified k-ratio method is the most practical for uncertainty quantification of βeff. Finally, total βeff uncertainty due to nuclear data for the VENUS-F critical configuration is determined to be approximately 2.7% with JENDL-4.0u, which is dominated by the delayed neutron yield of 235U. 相似文献
19.
I Takagi K Yamada T Sato T Hanaichi T Iwamoto L Jin 《Journal of electron microscopy》1990,39(1):67-68
The penetration and stainability of modified Sato's lead staining solution containing calcined lead citrate were studied. Modified Sato's lead solution was preserved for 1 week and for 2 years, each at room temperature and at 4 degrees C. Specimens were stained with these solutions to measure the stainability. After 2-min staining, specimens were stained to the depth of 1.0-1.2 microns even when there had been 2-year preservation of the staining solution. This modified solution could be preserved for a long time and good penetration and stainability could still be obtained. This solution is also suitable for the observation of semithin sections. 相似文献
20.
BACKGROUND: Cardiac allograft rejection is accompanied by cellular infiltration and tissue edema resulting in myocardial relaxation abnormalities. Doppler tissue imaging is capable of measuring myocardial relaxation velocities and is useful in the detection of heart rejection. However, the influence of ventricular loading conditions on myocardial relaxation velocities has not been studied. This study is performed to determine whether myocardial relaxation velocities are affected by left ventricular loading conditions. METHODS: Twenty heart transplant recipients without evidence of rejection by endomyocardial biopsy underwent preload and afterload reduction with nitroglycerin. The pulmonary wedge pressure was reduced from 18.2+/-0.9 to 12.0+/-0.9 mm Hg 9 (p=0.001) and the mean blood pressure from 130.0+/-5.6 to 116.1+/-7.0 mm Hg (p=0.001). Pulsed-wave Doppler tissue imaging was performed before and after administration of nitroglycerin, and the peak myocardial relaxation velocities of the inferior wall were measured. RESULTS: Myocardial relaxation velocities did not change with the administration of nitroglycerin; 0.188+/-0.009 to 0.178+/- 0.006 m/sec (p=0.4) in spite of a significant reduction in pulmonary capillary wedge pressure. Furthermore, there was no correlation between pulmonary capillary wedge pressure, mean arterial pressure, wall stress, and myocardial relaxation velocities. CONCLUSIONS: Loading conditions on the left ventricle have no influence on myocardial relaxation velocities. Therefore in heart transplant recipients changes in myocardial relaxation velocities by Doppler tissue imaging may be useful in the diagnosis of rejection, in spite of diverse loading conditions. 相似文献