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11.
《中国有色金属学会会刊》2020,30(1):160-170
The microstructure evolution and high-temperature mechanical properties of laser beam welded TC4/TA15 dissimilar titanium alloy joints under different welding parameters were studied. The results show that the weld fusion zone of TC4/TA15 dissimilar welded joints consists of coarsened β columnar crystals that contain mainly acicular α′ martensite. The heat affected zone is composed of the initial α phase and the transformed β structure, and the width of heat affected zone on the TA15 side is narrower than that on the TC4 side. With increasing temperature, the yield strength and ultimate tensile strength of the TC4/TA15 dissimilar welded joints decrease and the highest plastic deformation is obtained at 800 °C. The tensile strength of the dissimilar joints with different welding parameters and base material satisfies the following relation (from high to low): TA15 base material > dissimilar joints > TC4 base material. The microhardness of a cross-section of the TC4/TA15 dissimilar joints reaches a maximum at the centre of the weld and is reduced globally after heat treatment, but the microhardness distribution is not changed. An elevated temperature tensile fracture of the dissimilar joints is located on the side of the TC4 base material. Necking occurs during the tensile tests and the fracture characteristics are typical when ductility is present in the material. 相似文献
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《Journal of the European Ceramic Society》2020,40(5):2113-2119
The development of an adsorbent which can be easily transformed into stable ceramic waste forms through a simple route is necessary for the treatment of the radioactive wastewater. Herein, we report on the immobilization of uranium in cristobalite ceramic through adsorption on mesoporous SBA-15 and further sintering process. The mesoporous SBA-15 with short pore length was synthesized and employed to remove uranium from aqueous solution. Subsequently, the SBA-15 with adsorbed U (U/SBA-15) was solidified by sintering. The effects of sintering temperature and U content on the structure, densification and aqueous durability of the obtained cristobalite ceramic waste forms were investigated. The results indicate that the U/SBA-15 can be transformed into stable cristobalite ceramic after sintering at 1100–1400 °C for 6 h. Furthermore, all the obtained cristobalite ceramic waste forms exhibit good aqueous durability (∼10−4 g m-2 d-1). This work demonstrates a potential route and adsorbent to dispose the radioactive wastewater. 相似文献
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15.
Yan-chun ZHU Qing-xue HUANG Xiao-hui SHI Mei-rong SHUAI Wei-dong ZENG Yong-qing ZHAO Zhi-quan HUANG Li-feng MA 《中国有色金属学会会刊》2018,28(8):1521-1529
The microstructural evolution and precipitation location of the secondary phase of an as-cast Ti-25V-15Cr-0.3Si titanium alloy were investigated via isothermal compression experiments and heat treatment. The average aspect (length-to-width) ratio, average area and size of the grains at different heat treatment temperatures and holding time were analyzed and the effects of deformation and annealing time on the grain area and size were considered. It was found that the grain size was strongly influenced by the height reduction and holding time. Grain growth was significant when annealing time increased from 10 min to 2 h at 950 °C and height reduction of 30%; however, grain growth was minimal at annealing time between 2 and 4 h. Many dispersion particles were observed to form in continuous chains; the precipitation location was confirmed to be along initial grain boundaries, and the dispersion particles were identified to be Ti5Si3 phase by TEM. 相似文献
16.
Hideaki Kaneto Tomohiko Kimura Atsushi Obata Masashi Shimoda Kohei Kaku 《International journal of molecular sciences》2021,22(5)
While there are various kinds of drugs for type 2 diabetes mellitus at present, in this review article, we focus on metformin which is an insulin sensitizer and is often used as a first-choice drug worldwide. Metformin mainly activates adenosine monophosphate-activated protein kinase (AMPK) in the liver which leads to suppression of fatty acid synthesis and gluconeogenesis. Metformin activates AMPK in skeletal muscle as well, which increases translocation of glucose transporter 4 to the cell membrane and thereby increases glucose uptake. Further, metformin suppresses glucagon signaling in the liver by suppressing adenylate cyclase which leads to suppression of gluconeogenesis. In addition, metformin reduces autophagy failure observed in pancreatic β-cells under diabetic conditions. Furthermore, it is known that metformin alters the gut microbiome and facilitates the transport of glucose from the circulation into excrement. It is also known that metformin reduces food intake and lowers body weight by increasing circulating levels of the peptide hormone growth/differentiation factor 15 (GDF15). Furthermore, much attention has been drawn to the fact that the frequency of various cancers is lower in subjects taking metformin. Metformin suppresses the mechanistic target of rapamycin (mTOR) by activating AMPK in pre-neoplastic cells, which leads to suppression of cell growth and an increase in apoptosis in pre-neoplastic cells. It has been shown recently that metformin consumption potentially influences the mortality in patients with type 2 diabetes mellitus and coronavirus infectious disease (COVID-19). Taken together, metformin is an old drug, but multifaceted mechanisms of action of metformin have been unraveled one after another in its long history. 相似文献
17.
重点分析了KJ-15A矿井机车运输监控系统屏蔽线路的接线方法、常见故障类型及电缆检测和日常项目的维护。可为KJ-15A矿井机车运输监控系统屏蔽电缆的故障处理及系统的正常工作提供一定的理论参考,可为从事KJ-15A矿井机车运输监控系统日常维护的工作人员提供一些借鉴。 相似文献
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19.
Decomposing regional income inequality in China and Indonesia using two-stage nested Theil decomposition method 总被引:9,自引:0,他引:9
Takahiro Akita 《The Annals of Regional Science》2003,37(1):55-77
The objective of this paper is to present an inequality decomposition method, the two-stage nested Theil decomposition method,
which is an extension of the ordinary one-stage Theil decomposition method. The method is analogous to a two-stage nested
design in the analysis of variance (ANOVA). It considers the three-level hierarchical structure of a country: region-province-district,
and decomposes overall regional inequality, as measured by Theil indices based on district-level mean incomes, into three
components: the between-region, between-province, and within-province inequality components. The within-province component
is a weighted-average of within-province income inequalities for each province, while the between-province component is a
weighted-average of between-province income inequalities within each region. The method uses a district as the underlying
regional unit to measure regional income inequality, rather than a province, and thus can analyze the contribution of within-province
inequalities as well as between-province and between-region inequalities to the overall regional income inequality in a coherent
framework. This paper applies the two-stage nested Theil decomposition method to district-level income and population data
in China and Indonesia and explores factors determining regional income inequality in China and Indonesia.
Received: October 2000/Accepted: June 2002
The author is grateful to the Foundation of International Education (Kokusai Kyoiku Zaidan) and Japan Society for the Promotion
of Science (Grant-in-Aid for Scientific Research No. 12630073) for their financial support, and to anonymous referees for
helpful comments. 相似文献
20.
We propose a multidimensional approach to regional inequality as an alternative allocation mechanism for EU Structural Funds
remittances based on per capita GDP, particularly after EU enlargement. The indicators of regional inequality are combined
to a composite index by means of Maasoumi's aggregator function. We propose Partial Common Principal Component Aanalysis as
the estimator of the weights for the aggregator function. Application of the multidimensional approach to Spain shows that
there are substantial differences between the rankings of the regions obtained by means of the multidimensional approach and
the traditional approach based on per capita GDP. For Hungary, which is less developed than Spain, the rankings differ less. 相似文献