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排序方式: 共有894条查询结果,搜索用时 15 毫秒
851.
Shojiro Ochiai Shuichi Urakawa Kei Ameyama Yotaro Murakami 《Metallurgical and Materials Transactions A》1980,11(3):525-530
Single fiber-brittle zone model composites were prepared by the electroless plating method, in order to know the effect of
the interfacial bonding strength between the fiber and brittle zone on the fracture strength of the composites. For the case
of weak inter-facial bonding, the notch formed by the fracture of the brittle zone at an early stage of deformation was unable
to extend into the fiber due to a premature interfacial debonding. Therefore no deleterious effect of the brittle zone on
the fiber strength was found. For the case of strong interfacial bonding, the formed notch extended into the fiber, resulting
in loss of the fiber strength. The strength of such a composite was well explained by the theory recently proposed by Ochiai
and Murakami. The important parameters to describe the fracture behavior of the fiber coated with the brittle zone, the strain
energy release rate of the fiber and the permissible thickness of the brittle zone, below which the strength of the fiber
is not reduced, were experimentally determined. 相似文献
852.
853.
Drying behavior of a single suspended droplet of various protein and carbohydrate solutions was investigated experimentally. For small molecular weight carbohydrates such as sucrose and glucose, the constant-rate period was observed, which was followed by the falling rate period characterized as the “regular regime”. During the falling rate period. the drying rate was very low due to a sharp decrease of the water diffusion coefficient with decreasing water concentration No remarkable constant rate periods were observed for large-molecular carbohydrates and proteins. This is because the water diffusion coefficient is low even at high water concentrations. The drying curves or bovine serum albumin, skimmilk and model-food liquid solutions were found to be predicted by a computer simulation with the concentration dependent water diffusion coefficient of maltodextrin of dextrose equivalent =11. The experimental investigations on the ethanol and enzyme retention during drying indicated that the ethanol is lost during the costant-rate period and the enzyme inactivation occurs during the constant-rate period (regular regime). 相似文献
854.
855.
856.
Thermal shock resistance of an SiC fibre-(Nicalon®) reinforced borosilicate glass (Pyrex) and lithium aluminosilicate (LAS) matrix composite has been investigated experimentally in the temperature range 0–1000 K. Longitudinal Young's modulus and flexure strength of the composites after thermal shock were obtained as a function of thermal shock temperature. The results are discussed with the observed damage of the composite. The borosilicate glass matrix composite showed multiple cracking of the glass matrix perpendicular to the fibre axis when the thermal shock temperature was above 600 K. Decreases in Young's modulus and flexure strength were also recognized after multiple cracking of the matrix was initiated. On the other hand, the LAS matrix composite showed no damage at thermal shock temperatures below 800 K. However, at 800 K and above, microcracking of the matrix along the fibre axis was observed. After thermal shock, no decrease in the flexure strength was recognized, while the Young's modulus decreased due to microcracking of the matrix when the thermal shock temperatures were 800 K and above. It was found that the major advantage of the composite against thermal shock was to retain non-catastrophic failure properties even after the development of thermally induced damage in the composite. 相似文献
857.
Hisayoshi Iba Tongshik Chang Yutaka Kagawa Hiroyoshi Minakuchi Kuniaki Kanamaru 《Journal of the American Ceramic Society》1996,79(4):881-884
Optically transparent chopped oxynitride glass (SiAlCaON) fiber-reinforced glass matrix composites have been fabricated by hot-pressing. Four kinds of glass matrices were candidates in this study. The optical transmission properties of the composites were obtained in UV-visible and IR wavelength ranges. With selection of the optimal glass matrix and an appropriate processing procedure, an optically transparent glass matrix composite can be obtained. Within the framework of this study, the optical transmittance was strongly dependent on the optical transmittance of the hot-pressed glass matrix. The well-fabricated composite with a fiber volume fraction of 0.07 showed measured optical transmittance of 35%–50% in the UV-visible wavelength region and 80% in the IR wavelength region. 相似文献
858.
N Matsuura E Tashita J Yamamura Y Kagawa Y Takada 《Canadian Metallurgical Quarterly》1995,53(7):1643-1647
Integrin plays an important role in tumor metastasis through its interaction with extracellular matrix and endothelial cell. We have examined the role of each integrin in tumor metastasis by using transfection of integrin cDNA into various cells. Transfection of integrin alpha 2 subunit into RD cells, human rhabdomyosarcoma cells which do not express integrin alpha 2 beta 1, potentiated the frequency of metastases in various organs; lung, bone, adrenal gland, lymph node. alpha 4-transfectant of Chinese hamster ovary (CHO) cells, which do not have alpha 4 beta 1 on the cell surface, metastasized to bone through its interaction with VCAM-1 in the bone marrow stroma cells. On the other hand, alpha 5-transfectant of CHO cells was much less tumorgenic than parent CHO cells. These data suggest integrin influence tumor metastasis sometimes favorably and sometimes unfavorably according to the activity and the balance of various integrins. 相似文献
859.
S.J. Zhu Y. Kagawa M. Mizuno S.Q. Guo Y. Nagano H. Kaya 《Materials Science and Engineering: A》1996,220(1-2):100-108
In situ observation of cyclic fatigue crack propagation of SiC-fiber reinforced SiC composite at room temperature has been carried out by laser microscopy. Both smooth (unnotched) and notched specimens are used for tension-tension cyclic fatigue tests. Cracks initiate at the comers of large pores during loading in smooth specimens. In notched specimens cracks are formed at the interfaces between fibers and matrix that are connected to the notch. The balance between the fiber bridging in the wake of propagating crack tip and the breakage of bridged fibers by the degradation of interfaces maintains a steady cyclic crack propagation. Crack propagation rate gradually decreases with time after the maximum load being applied. 相似文献
860.
Hideki Shirakawa Sakuji Ikeda Masua Aizawa Junichi Yoshitake Shuichi Suzuki 《Synthetic Metals》1981,4(1):43-49
Polyacetylene films were characterized as an electrode material in aqueous solutions. The trans polyacetylene films behaved as electrodes under reducing conditions. Oxygen gas evolution was greatly retarded under oxidizing conditions, primarily due to the high reactivity with oxygen. Visible light illumination resulted in a positive shift in electrode potential. The electrode developed photopotential reversibly in accord with illumination. The polyacetylene electrode gave cathodic photocurrent when contacted with a deoxygenated acetate buffer. The cathodic photocurrent increased with decreasing pH, ranging from 0 to 5.5 × 10?6 A/cm2. The possible use of polyacetylene electrodes for photoenergy conversion is discussed. 相似文献