440 research outputs found

    ホイスラー合金を使った面直電流磁気抵抗素子の開発

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    この博士論文は内容の要約のみの公開(または一部非公開)になっています筑波大学 (University of Tsukuba)201

    Stochastic Efficiency Analysis with a Reliability Consideration

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    Stochastic Data Envelopment Analysis (DEA) models have been introduced in the literature to assess the performance of operating entities with random input and output data. A stochastic DEA model with a reliability constraint is proposed in this study that maximizes the lower bound of an entity\u27s efficiency score with some pre-selected probability. We define the concept of stochastic efficiency and develop a solution procedure. The economic interpretations of the stochastic efficiency index are presented when the inputs and outputs of each entity follow a multivariate joint normal distribution

    Sepsis-induced cardiac dysfunction: Pathophysiology and experimental treatments

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    PhDThe severity of cardiac dysfunction predicts mortality in septic patients. In this thesis, I have investigated the pathophysiology and the novel therapeutic strategy to attenuate cardiac dysfunction in experimental sepsis. I have developed a model of cardiac dysfunction caused by lipopolysaccharide (LPS)/peptidoglycan (PepG) co-administration or polymicrobial sepsis in young and old, male and female mice. There is good evidence that females tolerate sepsis better than males. Here, I have demonstrated for the first time that the cardiac dysfunction caused by sepsis was less pronounced in female than in male mice; this protection was associated with cardiac activation of a pro-survival pathway [Akt and endothelial nitric oxide synthase], and the decreased activation of a pro-inflammatory signalling pathway [nuclear factor (NF)-κB]. Patients with chronic kidney disease (CKD) requiring dialysis have a higher risk of sepsis and a 100-fold higher mortality. Activation of NF-κB is associated with sepsis-induced cardiac dysfunction and NF-κB is activated by IκB kinase (IKK). Here, I have shown that 5/6th nephrectomy for 8 weeks caused a small, but significant, cardiomyopathy, cardiac activation of NF-κB and expression of inducible nitric oxide synthase (iNOS). When subjected to LPS or polymicrobial sepsis, CKD mice exhibited exacerbation of cardiac dysfunction and cardiac activation of NF-κB and iNOS expression, which were attenuated by a specific IKK inhibitor (IKK 16). Thus, selective inhibition of IKK may represent a novel therapeutic approach for the sepsis-induced cardiac dysfunction in CKD patients. Activation of transient receptor potential vanilloid receptor type 1 (TRPV1) improves outcome in sepsis/endotoxaemia. The identity of the endogenous activators of TRPV1 and the role of the channel in the cardiac dysfunction caused by sepsis/endotoxaemia is unknown. Here, I have shown that activation of TRPV1 by 12-(S)-HpETE and 20-HETE (potent ligands of TRPV1) leads to the release of calcitonin gene-related peptide (downstream mediator of TRPV1 activation), which protects the heart against the cardiac dysfunction caused by LPS.China Scholarship Counci

    IPO price determination in Chinese growth enterprise

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    1 online resource (v, 39 p.)Includes abstract and appendices.Includes bibliographical references (p. 28-30).After more than 20 years of development, China’s capital markets are not yet mature. In order to guide the reform of mature market, the study on the IPO price determination in GEM is necessary. We employ the factor analysis and multiple regression to analyze the issue of IPO pricing on Chinese GEM. Through factor analysis, five factors are extracted which reflect the companies’ intrinsic value. The result of the regression shows that IPO pricing of Chinese GEM is fair. We verify the nonexistence of behavior which lowers the offering price by underwriter. By way of excluding the irrational pricing hypothesis, we conduct the analysis of the IPO underpricing depending on the external factors. The result proves that the market expectation and speculation from investors affect the IPO underpricing most

    Genetic Variation and Geographical Differentiation of \u3cem\u3eElymus nutans\u3c/em\u3e (Poaceae: Triticeae) from West China

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    Elymus nutans Griseb. is not only an important alpine forage grass, but also as a crucial gene pool for improving cereal crops. Understanding and maintaining the genetic diversity of the species are essential for both conservation strategy and breeding programs. However, little is known about its genetic and geographical differentiation patterns. E. nutans is a perennial, caespitose and allohexaploid (2n=6x=42) species that contains the St, H and Y genomes. It is native to temperate and tropical Asia, ranging from western and central Asia in the west to China and Mongolia in the east, from Russia in the north to India and the Himalayas areas in the south (Clayton et al. 2006). It is distributed in the north, northwest and southwest China, particularly in the Qinghai-Tibet Plateau. E. nutans is a valuable forage grass in the alpine regions that is resistant to cold, drought and pests, which can be used to improve cereal crops. In addition, it can play an important role in the restoration of disturbed grasslands and the establishment of artificial grasslands, especially at altitudes from 3,000 to 4,500 m (Chen and Jia 2000). During recent decades, its distribution has contracted because of over-exploitation, habitat destruction and fragmentation. Therefore, it is urgent to understand and monitor the genetic and geographical differentiation of wild germplams of E. nutans

    Characterization of transient groundwater flow through a high arch dam foundation during reservoir impounding

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    AbstractEven though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world's highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks, which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality (PVI) method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results

    Experimental research on dynamic characteristics of a hybrid gas bearing-rotor system for high-speed permanent magnet machine

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    An experiment on the vibrational characteristics of a hybrid gas bearing-rotor system in a 45 kW high-speed permanent magnet machine test rig is conducted. Nonlinear methods of measurements and analyses, including bifurcation maps, frequency spectra, and axis orbits, are adopted to evaluate sub-synchronous vibration in rotor acceleration. The effects of bearing supply pressure and speed accelerating rates on the stability of the gas bearing-rotor system are determined. Experimental results show that half-speed whirling of the gas film is eliminated and the start of gas film whipping is delayed by using the appropriate bearing supply pressure plan, thereby improving stability. Meanwhile power frequency vibrational amplitude is the smallest during the acceleration process, including the critical speed, when the appropriate speed accelerating rates are employed
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