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排序方式: 共有507条查询结果,搜索用时 15 毫秒
211.
Masaharu Iwamoto Qing-Qing Ni Teruhiko Fujiwara Ken Kurashiki 《Engineering Fracture Mechanics》1999,64(6):2779-764
Three kinds of representative carbon fiber reinforced unidirectional composite materials are used, and their intralaminar fracture behavior is investigated by using the double-cantilever beam (DCB) specimen with a simultaneous acoustic emission measuring. In Part I, the experimental results on the crack propagation, the bridging fibers, the intralaminar fracture toughness acoustic emission characteristics and microscope observations were obtained. Here, we use a bridging fiber model to analyze the debonding force acting on a bridging fiber and try to estimate the number of bridging fibers during the crack propagating process. At the same time, the intralaminar fracture toughness is calculated by both the adhesive force model and the finite element analysis. As a result, it is found that the intralaminar fracture toughness without the bridging fibers will have a constant value during the crack propagation, but it increases greatly when bridging fibers exist. It is clear that the bridging fibers play an important role in the intralaminar fracture toughness. The debonding forces acting on the bridging fibers and the number of bridging fibers are obtained. Furthermore, the quantitative estimation of the increment of the intralaminar fracture toughness contributed by bridging fibers is made according to the adhesive force model and it is comparable with the results obtained by the finite element analysis. 相似文献
212.
Masanori Ohta Masaharu Kumashiro Yasumasa Eguchi Yusaku Morita Yoshimasa Konno Hiroshi Yamato 《Ergonomics》2014,57(8):1265-1273
Work ability is based on the balance between personal resources and work demand. This study focused on the personal resources component of work ability. The aims of this study were to elucidate the association between work ability and cardiovascular (CV) risk factors, particularly oxidative stress, and to estimate the effect of a community-implemented lifestyle modification programme on work ability and CV risk factors. Urinary 8-iso-prostaglandin F2α (PGF2α), a biomarker of oxidative stress, was negatively correlated with psychological resources, as measured by the Work Ability Index (WAI). Overall WAI score was unchanged following the programme, while CV risk factors and antioxidative activity improved. A reduction in PGF2α levels was correlated with an improvement in subjective work ability relative to job demands, as assessed by a WAI item. Taken together, the results suggest that lifestyle modification programmes enhance the personal resources component of work ability and are associated with a reduction in oxidative stress. 相似文献
213.
Kentaro Nakahara Jiro Iriyama Shigeyuki Iwasa Masahiro Suguro Masaharu Satoh Elton J. Cairns 《Journal of power sources》2007
Poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) is the most common active material with a stable radical molecular structure used for lithium rechargeable cells. Because it is an organic active material, PTMA can be dissolved easily in various solvents. Using a solution of active material in the electrode making process, we formed an extremely large surface area between the active material and the conducting additive. The electrode has excellent power capability and can be charged and discharged in 1 min. We believe that this cell can be used like an electric double layer capacitor. We also believe that the cell, whose cycle life is good, retaining 89% of original capacity after 1000 cycles, can be put into practical use. 相似文献
214.
The surimis prepared from the three fish species, red barracuda Sphyraena pinguis, yellow sea bream Dentex tumifrons, and spotted shark Mustelus manazo, were fractionated by sieving through a 30-mesh stainless steel sieve. Chemical analyses revealed significant differences in the collagen content among the residual fraction on the sieve (fraction A), the passed fraction (fraction C), and the original surimi before sieving (fraction B): the fractions A and B showed values 10–20 and 5–10 times higher than those of the fraction C, respectively, for all the species examined. Histological observation indicated the richness of the thick connective tissues derived from myocommata in fractions A and B, while thick connective tissue was hardly observed in fraction C. These results suggested that the present fractionation method may have an effect of reducing the collagen content to about 10–20% of the original value, and that a large part of collagen in fish surimi exists in the relatively thick connective tissue, probably derived from myocommata. 相似文献
215.
Akio Kawabata Masaru Yoshinaka Ken Hirota Osamu Yamaguchi 《Journal of the American Ceramic Society》1995,78(8):2271-2273
Chromium (III) oxide (Cr2 O3 ) crystallizes at low temperatures from an amorphous material prepared by adding hydrazine monohydrate to an aqueous solution of Cr(NO3 )3 -9H2 O. Individual particles of Cr2 O3 tend toward a hexagonal morphology above 800°C. Well-densified Cr2 O3 pellets (98.8% of theoretical density) have been fabricated by hot isostatic pressing for 2 h at 1100°C and 196 MPa. Their fracture toughness is 4.4 MPa.m1/2 . The sample annealed in air for 12 h at 1300°C exhibits a high electrical conductivity of 3.6 Ω-1 .m-1 at 700°C. 相似文献
216.
Platelet-activating factor (PAF) and leukotriene B4 are potent lipid mediators of endothelium-granulocyte interaction which results in granulocyte-dependent increased microvascular
permeability. The specific mechanism by which PAF induces granulocyte-mediated endothelial injury has not been fully investigated.
Digital imaging photonic intensified microscopy has revealed that PAF effectively induces granulocyte-mediated oxidative stress
on microvascular beds. The method has made it possible to visualize luminol-dependent photonic burst released from PAF-treated
microvascular beds in the rat mesentery. The photonic activities clearly corresponded to the localization of sticking granulocytes
in post-capillary venules. By contrast, no significant chemilumigenic response could be detected in the leukotriene B4-induced activation of endothelium-granulocyte interactionin vivo. The present findings suggest that oxygen radicals are not prerequisites for granulocyte adhesion in the microcirculation
and provide evidence for a dissociation ofin vivo granulocyte function between leukotactic and oxidative activation in leukotriene B4-induced microvascular changes.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
217.
Hiroyuki ShimizuMasaru Yoshinaka Ken HirotaOsamu Yamaguchi 《Materials Research Bulletin》2002,37(9):1557-1563
Fine MoSi2 powders containing a small amount of Mo5Si3 have been prepared by self-propagating high-temperature synthesis (SHS), followed by spark plasma sintering (SPS) for 10 min at 1200-1500°C and 30 MPa. Dense MoSi2 materials, in which the grain size is ∼7.5 μm, have been fabricated at 1300°C. They exhibit excellent mechanical properties: Vicker’s hardness Hv (10.6 GPa), fracture toughness KIC (4.5 MPa m1/2), and bending strength σb (560 MPa). The strength of 325 MPa can be retained up to 1000°C. 相似文献
218.
219.
Efficient production of the C-terminal domain of secretory leukoprotease inhibitor as a thrombin-cleavable fusion protein in Escherichia coli 总被引:1,自引:0,他引:1
Masuda Ken-ichi; Kamimura Takashi; Kanesaki Masaharu; Ishii Koji; Imaizumi Atsushi; Sugiyama Takashi; Suzuki Yoji; Ohtsuka Eiko 《Protein engineering, design & selection : PEDS》1996,9(1):101-106
We have developed a high-level production system for the C-terminaldomain of secretory leukoprotease inhibitor (SLPI) to investigateits pharmacological activities. A gene for the C-terminal domainof SLPI, (Asn55-AlalO7)SLPI, was constructed from chemicallysynthesized deoxyoligonucleotides. It was fused to a gene forthe N-terminal portion of human growth hormone via a DNA sequenceencoding Leu-Val-Pro-Arg, which can he cleaved by thrombin.The fused gene was expressed in Escherichia coli under the controlof a trp promoter, and the fusion protein was obtained as aninclusion body. After sulfonation of the cysteine residues,the sulfonated fusion protein was cleaved at the desired siteby thrombin. Sulfonated (Asn55-Ala107)SLPI was refolded in Trisbuffer containing reduced and oxidized glutathione. The resulting(Asn55-Ala107) SLPI was purified by cation-exchange chromatographyand reverse-phase high performance liquid chromatography. Thefinal yield was 50 mg/l culture. (Asn55-Ala107)SLPI was as activeagainst elastase as, but had less trypsin inhibitory activitythan, native SLPI. This system is suitable for the large-scaleproduction of the C-terminal domain of SLPI, which is an elastase-specificinhibitor. 相似文献
220.
Tomohito Hamazaki Masaharu Urakaze Saburo Yano Yasuji Soda Akira Miyamoto Kohji Kubota Fumio Ibuki 《Lipids》1987,22(12):1031-1034
An injectable emulsion of docosahexaenoic acid (DHA) was prepared. One hundred ml of the emulsion contained 3 g of 93%-pure
1,2,3-tridocosahexaenoylglycerol (DHA-TG), 1.2 g of 93%-pure 2-docosahexaenoyl-phosphatidylcholine as an emulsifier and 2.5
g of glycerol. Thirty ml of the emulsion of DHA-TG was injected into three rabbits on days 1 and 4 of the study. Blood was
taken on day 0, on day 4 just before the second injection and on day 7. The percentage of DHA in the total phospholipid fraction
of platelets increased from 0.46% (day 0) to 1.88% (day 4, p<0.05) and 3.66% (day 7; p<0.02 vs day 0). The percentage of eicosapentaenoic
acid (EPA) increased from 0.46% (day 0) to 1.03% (day 4, p<0.02) and 1.63% (day 7: p<0.05 vs day 0). The percentage of arachidonic
acid (AA) decreased from 9.45% (day 0) to 4.31% (day 4, p<0.05) and 6.68% (day 7; p<0.02 vs day 0). The percentage of DHA
in the total phospholipid fraction of erythrocyte membranes increased from 0.23% (day 0) to 0.91% (day 4, p<0.05) and 1.52%
(day 7; p<0.005 vs day 0); that of EPA increased from 0.21% (day 0) to 0.34% (day 4, p<0.005%) and 0.52% (day 7, p<0.01 vs
day 0); that of AA was unchanged. Blood lipids were the same before and after the two injections of the emulsion, except that
free fatty acids decreased markedly from 0.32 to 0.06 mEq/1 (p<0.02). On day 8, free AA (2 mg/kg) was injected into ear veins
of the three treated rabbits and of four control rabbits (not treated with DHA-TG). All the control rabbits died a few minutes
after the AA injection, but none of the DHA-treated rabbits died after AA injection (p<0.01). An emulsion of DHA-TG may be
useful for patients having immediate risk of thrombosis or for those who need DHA but cannot take it orally. 相似文献