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Jian-Hong Wu Y. Ohnishi S. Nishiyama 《International Journal of Rock Mechanics and Mining Sciences》2004,41(5):731-743
In this paper, the mechanical behavior of inclined jointed rock masses during tunneling is considered. Such rock masses can be considered as an assembly of discrete blocks with the discontinuities having a significant influence on the mechanical behavior. To simulate this situation, a discrete numerical analysis method, Discontinuous Deformation Analysis (DDA), is applied. The DDA results show the existence of stress arching in the rock masses during tunneling. This stress arching is the primary influence on the stress distribution and surface subsidence. In addition, the stress arching is affected by the dip angle of the jointed rock masses. Moreover, the DDA results are in good agreement with experiments, explaining the reason for the asymmetrical vertical stress and surface subsidence obtained in laboratory tests. These results suggest that DDA can be applied to model the tunneling behavior of complicated discontinuous rock masses. 相似文献
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Changes in monochlorodimedone (MCD) chlorinating rates with free chlorine (mixture of HOCl and OCl-) and ammonia monochloramine (NH2Cl) in water at pH 7 by the addition of isocyanuric acid (H3Cy) were determined at room temperature. Decreases in MCD absorbance at 290nm in equimolar (0.04mM) reactions of MCD and free available chlorine solutions containing H3Cy (0.01-1.60 mM) were recorded in a stopped-flow spectrophotometer. The rates indicate second-order reactions. Since the rate with free chlorine was high (> 7.6 x 10(6) M(-1) s(-1)), the amounts of free chlorine in the solutions could be distinguished from that of chlorinated cyanurates. The chlorinating rates with chlorinated cyanurates decreased with an increase in H3Cy concentrations. Plotting the rates against the molar ratio of chlorine to H3Cy showed a linear correlation and the rates with chlorinated cyanurates (H2ClCy) was estimated at 0.5 x 10(5) M(-1) s(-1). In contrast, the rates with the NH2Cl solution containing H3Cy increased with an increase in H3Cy concentrations, increasing from 1.2 x 10 to 2.7 x 10 M(-1) s(-1) by the addition of 1.55 mM H3Cy. The DPD color development rates (OD512/t1/2/M) with free available chlorine (0.015mM) declined from 1.3 x 10(5) to 0.9 x 10(5)M(-1) by the addition of 0.61 mM H3Cy. 相似文献
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Reo Etani Takahiro Kataoka Yuichi Nishiyama Yuji Takata 《Journal of Nuclear Science and Technology》2013,50(12):1512-1518
It has been reported that radon inhalation activates antioxidative functions in liver and has an antioxidative effect against hepatopathy similar to that of the antioxidative effects of ascorbic acid (VC) or α-tocopherol (VE). In this study, we examined the combined effects of radon inhalation and antioxidant vitamin administration on acute alcohol-induced hepatopathy in mice. ICR mice were subjected to intraperitoneal (i.p.) administration of alcohol after pretreating with air only (sham) or radon at a concentration of approximately 2000 Bq/m3 for 24 hours and i.p. administration of VC (300 mg/kg body weight) or VE (300 mg/kg body weight). In mice injected with alcohol, the combined radon and antioxidant vitamins treatment significantly decreased the activities of glutamic oxaloacetic transaminase in serum compared to not only the alcohol-administered group (sham group), but also the radon inhalation with alcohol administration group or the vitamin and alcohol administration group. In addition, radon inhalation significantly increased the antioxidant level, in such as the catalase activity and the total glutathione content in liver compared to the sham group. These results suggested that the combined radon and antioxidant vitamin treatment could effectively inhibit alcohol-induced hepatopathy in mice without any antagonizing action. 相似文献
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Mast cells (MCs) play critical roles in Th2 immune responses, including the defense against parasitic infections and the initiation of type I allergic reactions. In addition, MCs are involved in several immune-related responses, including those in bacterial infections, autoimmune diseases, inflammatory bowel diseases, cancers, allograft rejections, and lifestyle diseases. Whereas antigen-specific IgE is a well-known activator of MCs, which express FcεRI on the cell surface, other receptors for cytokines, growth factors, pathogen-associated molecular patterns, and damage-associated molecular patterns also function as triggers of MC stimulation, resulting in the release of chemical mediators, eicosanoids, and various cytokines. In this review, we focus on the role of interleukin (IL)-10, an anti-inflammatory cytokine, in MC-mediated immune responses, in which MCs play roles not only as initiators of the immune response but also as suppressors of excessive inflammation. IL-10 exhibits diverse effects on the proliferation, differentiation, survival, and activation of MCs in vivo and in vitro. Furthermore, IL-10 derived from MCs exerts beneficial and detrimental effects on the maintenance of tissue homeostasis and in several immune-related diseases including contact hypersensitivity, auto-immune diseases, and infections. This review introduces the effects of IL-10 on various events in MCs, and the roles of MCs in IL-10-related immune responses and as a source of IL-10. 相似文献
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Yuta Nishiyama Kimiko Kato Keisuke Kawasaki Masaki Nagasawa Isao Hasegawa 《Artificial Life and Robotics》2014,19(2):181-185
In this paper, we propose that the human brain develops a system to cover OTHER. This capital “OTHER” represents the transcendental other in infancy and the latent other later in life. The system grows to cover the transcendental other through the developmental process of objective–subjective distinction, and thereafter the latent other is found as a duality of the system later in life. To argue the emergence of such system regarding social conceptualization, we introduce experiments in which we verify that preschoolers abstract, categorize, and evaluate social relationships. The results show that children around 6 years old exhibit early social conceptualization and rudimentary objective–subjective distinction. Moreover, we claim that early social conceptualization is acquired through developing the heterarchical system when the experiments are regarded as communication between the participant and experimenter. Human beings may regard this heterarchical system as the self. 相似文献
9.
Phase transformation and interface segregation behavior in Si3N4 ceramics sintered with La2O3–Lu2O3 mixed additive 下载免费PDF全文
Ryosuke Urakami Yukio Sato Masayoshi Ogushi Takeshi Nishiyama Aoi Goto Kazuhiro Yamada Ryo Teranishi Kenji Kaneko Mikito Kitayama 《Journal of the American Ceramic Society》2017,100(3):1231-1240
Microstructure and mechanical property of silicon nitride (Si3N4) ceramic are strongly dependent on the selection of sintering additives. When rare‐earth (RE) oxide is used as the sintering additive, segregation of RE ions at interface between Si3N4 grain and intergranular glassy film (IGF) is believed to play a critical role. Although the ionic radius of RE ion is known to be an empirical parameter to modify the mechanical property, the correlation between the segregated ions and their ionic radii is still under controversy. In order to address this issue, (i) rate of α‐β phase transformation and (ii) segregation behavior at the interface were studied for Si3N4 ceramics sintered using mixture of La2O3 and Lu2O3 as additives in this study. Specimens of Lu content 30% and higher exhibited lower activation energies for the α‐β phase transformation as compared with those of Lu content 20% and lower. In terms of the segregation behavior, La was preferably segregated at one site and Lu at the other site along β‐Si3N4/IGF interface in the specimens of Lu content 30% and higher. It is understood from these results that Lu segregation site should be more closely related with grain growth. 相似文献
10.
N. Nishiyama K. Takenaka N. Saidoh M. Futamoto Y. Saotome Akihisa Inoue 《Journal of Alloys and Compounds》2011
With the aim of developing a novel perpendicular bit-patterned-media, combined process of thermal imprinting of glassy alloy thin film and embedding Co/Pd multilayer was developed. Nano hole array with a hole diameter of 30 nm was successfully formed onto Pd-based glassy alloy thin film by thermal imprinting. Co/Pd multilayer was overlaid on a textured Pd-based glassy alloy thin film. After finishing by sputter etching, prototype bit-patterned-media was prepared. Switching behavior examined under magnetic field of ±10 kOe reveals that the isolated magnetic dots began to switch at 10 kOe. These results suggest that the prototype composite has a strong possibility for the realization of next generation bit-patterned-media with high data density. 相似文献