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排序方式: 共有4335条查询结果,搜索用时 31 毫秒
31.
Toshio Kimura Hideto Kajiyama Ryuichi Yazaki Takashi Yamaguchi 《Journal of Materials Science》1996,31(15):4149-4157
The densification and microstructure development of ZnO containing Zn7Sb2O12, ZrO2, and aggregated ZnO were investigated to elucidate the effect of nondensifying inclusions on the sintering of ceramic/ceramic composites. The inclusion retarded the densification, and the degree of retardation was found to depend on the chemical species of inclusion; Zn7Sb2O12 had the largest effect, followed by ZrO2 and then aggregated ZnO last. The experimental results for aggregated ZnO was explained by the theory which predicts the generation of backstresses. The backstresses give a less significant effect on the densification. For Zn7Sb2O12 and ZrO2, the microstructure of the matrix varied with distance from an inclusion particle; much porosity was observed in the region surrounding the inclusion. Circumferential voids, which are responsible for the suppression of densification, form during the initial stage of sintering. Inclusion particles generate an anchoring effect which retards the densification of the matrix immediately surrounding the inclusion particle during the intermediate stage.Supported by the Inamori Foundation. 相似文献
32.
Y Yonemura H Kimura S Fushida K Tugawa Y Nakai M Kaji L Fonseca A Yamaguchi I Miyazaki 《Canadian Metallurgical Quarterly》1993,71(8):2448-2453
BACKGROUND: Proliferative activities of tumors are thought to be prognostic features of malignant tumors, but their value as measured by proliferating cell nuclear antigen (PCNA) labeling remains unclear in gastric cancer. METHODS: PCNA labeling rates (LR) were quantified in 121 paraffin-embedded biopsy specimens from primary tumors by immunocytochemistry. RESULTS: Immunohistochemical analyses have demonstrated that PCNA presents an intense staining in the nuclei of tumor cells and mucous neck cells of gastric glands. The PCNA LR ranged from 12% to 79% (mean +/- standard deviation), and a significant correlation was found between bromodeoxyuridine labeling indices and PCNA LR: PCNA LR were closely associated with tumor size, serosal invasion, and nodal involvement. The patients with tumors with high PCNA LR (greater than 40%) were dead significantly earlier than were those with tumors with low PCNA LR: When the PCNA LR and all the clinicopathologic parameters were entered into a Cox regression model, PCNA LR emerged as an independent prognostic factor. CONCLUSION: These results indicate that PCNA LR may be a potentially useful prognostic factor for gastric cancer. 相似文献
33.
Y Kubota T Tanaka G Yamaoka M Yamaguchi H Ohnishi K Kawanishi J Takahara S Irino 《Canadian Metallurgical Quarterly》1996,10(4):720-726
We report a large kindred in which a punctate palmoplantar keratoderma (PPK) is associated with malignancy, including Hodgkin's disease, renal, breast, pancreatic and colonic adenocarcinomas. The family was traced through four generations, and over 320 individuals were identified, of whom 49 had punctate PPK. The punctate PPK appeared to be inherited as an autosomal dominant trait with variable penetrance. Ten of the 43 adults (23%) with punctate PPK developed malignancies, and five of these developed before the age of 50. Of the 271 unaffected individuals, six (2%) have developed malignancies, one prior to the age of 50. The association of keratoderma and malignancy is discussed. 相似文献
34.
Thi Thi Nge Makiko Yamaguchi Naruhito Hori Akio Takemura Hirokuni Ono 《应用聚合物科学杂志》2002,83(5):1025-1035
Polyelectrolyte complex based on chitosan and acrylic acid monomer by photoinitiated free‐radical polymerization in the absence of crosslinker showed a large transition in swelling in response to changes in pH of surrounding medium. Their ability to swell arises from polyelectrolyte interactions and molecular structure of the complex. The main properties of interest that related to the molecular structure, swelling volumes, glass transition temperature, and elastic modulus of the complex were investigated. The effect of water content, the only variable in the sample component, played an important role in molecular structure of the complex and as a consequence, the extent of intermolecular linkage, especially amide bonds which in turn governed the degree of swelling of the polyelectrolyte complex in this study. The decreased degree of swelling and higher temperature shift of glass transition temperature was found with increased water content, whereas increased modulus of elasticity of dry complex was found in lower water content of synthesis component. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1025–1035, 2002 相似文献
35.
Yutaka Asako Hisayoshi KamikogaHisashi Nishimura Yoshiyuki Yamaguchi 《International Journal of Heat and Mass Transfer》2002,45(11):2243-2253
Compression is one solution to improve the strength of softwoods. The effective thermal conductivities of compressed Japanese cedars (cryptomeria japonica), which were compressed in the radial direction of the wood, were measured. Both the effective thermal conductivities in the tangential and fiber directions increase proportionally to the density increment due to the compression. However, the thermal conductivity in the radial direction (compression direction) increases slightly with the density increment. Numerical computations were conducted to explain the characteristics of thermal conductivity in the radial direction by using a microscopic heat conduction model for the compressed wood. The numerical results were compared with the measured values. And the physical mechanism of the heat conduction in the compressed woods is discussed. 相似文献
36.
Toshiji Mukai Koichi Ishikawa Kenji Higashi 《Metallurgical and Materials Transactions A》1995,26(10):2521-2526
Three IN905XL aluminum alloys with fine grain (1 μm), intermediate grain (3 μm), and coarse grain (5 μm) have been developed
by a combination of mechanical alloying (MA) and conventional extrusion in order to investigate their mechanical properties
at dynamic strain rates of 1 × 103 and 2 × 103 s−1 and a quasi-static strain rate of 10-3 s−1. Flow stresses are found to increase with decreasing grain size for all the strain rates tested. Negative strain-rate sensitivity
of flow stress is observed up to 1 × 103 s−1 in both intermediate- and coarse-grained IN905XL. At the highest strain rate of 2 × 103 s−1 however, all samples showed a positive strain-rate sensitivity of strength. Total elongation at high strain rates is generally
larger than that at low strain rates. Total elongation also decreases with grain size for all the strain rates. This decrease
in elongation results from an initiation of microcracks at interfaces between the matrix and particles finely dispersed near
grain boundary regions, introduced during MA processing; then, this initiation leads elongation of alloys to small limited
values.
Formerly with the Department of Mechanical Systems Engineering, University of Osaka Prefecture.
This article is based on a presentation made in the symposium “Dynamic Behavior of Materials,” presented at the 1994 Fall
Meeting of TMS/ASM in Rosemont, Illinois, October 3-5, 1994, under the auspices of the TMS-SMD Mechanical Metallurgy Committee
and the ASM-MSD Flow and Fracture Committee. 相似文献
37.
38.
Yamaguchi Y. Mitsumoto M. Sengoku M. Abe T. 《Geoscience and Remote Sensing, IEEE Transactions on》1992,30(1):186-189
An FM-CW radar system was applied to detect a human body buried in a very wet snowpack. This radar uses the L -band microwave frequency with a maximum output power of 100 mW, and utilizes digital signal processing techniques. Field experiments were carried out to detect and map a human body embedded at a depth of 125 cm in a natural snowpack. The radar is shown to have a potential ability to detect avalanche victims, indicating that it may become a tool for snow rescuer operations 相似文献
39.
Mr.KoichiChujo 《国外电子测量技术》2003,22(6):2-3,6
本文着重论述了波形测量技术的最新发展趋势。 相似文献
40.
The conventional loading criterion in the theory of plasticity becomes ambiguous when it is applied to materials that exhibit straining softening. For instance, it can not differentiate the softening behavior from the unloading process. On the other hand, the loading criterion proposed recently by Qu and Yin is free from such problems, and is more suitable for a general elasto-plastic analysis by finite element method. In the first part of this paper the proposed loading criterion is first reviewed and discussed to highlight the difficulties associated with the inequality conditions used in the conventional as well as the proposed loading criteria. This paper then proceeds to discuss the proposed criterion and reveals its implications. Although the proposed inequality conditions are not generally known in the field, it is found that they are essential and significant in the theory of plasticity. 相似文献