617 research outputs found

    The Impact of Capital Inflows on Emerging East Asian Economies: Is Too Much Money Chasing Too Little Good?

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    In recent years, emerging East Asian economies have experienced large capital inflows-especially a surge in portfolio inflows-and an appreciation of asset prices such as equities, land, and both nominal and real exchange rates. The paper reviews why a surge in capital inflows can increase asset prices, and then empirically investigates the effects by employing a panel vector autoregression (VAR) model. The empirical results suggest that capital inflows have indeed contributed to the asset price appreciation in this region, although capital inflow shocks explain a relatively small part of asset price fluctuations. How to manage these capital inflows is also discussed.Capital inflows; portfolio inflows; asset prices

    Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2

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    An abrupt first-order metal-insulator transition (MIT) without structural phase transition is first observed by current-voltage measurements and micro-Raman scattering experiments, when a DC electric field is applied to a Mott insulator VO_2 based two-terminal device. An abrupt current jump is measured at a critical electric field. The Raman-shift frequency and the bandwidth of the most predominant Raman-active A_g mode, excited by the electric field, do not change through the abrupt MIT, while, they, excited by temperature, pronouncedly soften and damp (structural MIT), respectively. This structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure

    Abrupt metal-insulator transition observed in VO2 thin films induced by a switching voltage pulse

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    An abrupt metal-insulator transition (MIT) was observed in VO2 thin films during the application of a switching voltage pulse to two-terminal devices. Any switching pulse over a threshold voltage for the MIT of 7.1 V enabled the device material to transform efficiently from an insulator to a metal. The characteristics of the transformation were analyzed by considering both the delay time and rise time of the measured current response. The extrapolated switching time of the MIT decreased down to 9 ns as the external load resistance decreased to zero. Observation of the intrinsic switching time of the MIT in the correlated oxide films is impossible because of the inhomogeneity of the material; both the metallic state and an insulating state co-exist in the measurement volume. This indicates that the intrinsic switching time is in the order of less than a nanosecond. The high switching speed might arise from a strong correlation effect (Coulomb repulsion) between the electrons in the material.Comment: 5 pages, 5 figure

    In-Depth Investigation of Statistical and Physicochemical Properties on the Field Study of the Intermittent Filling of Large Water Tanks

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    Large-demand customers, generally high-density dwellings and buildings, have dedicated ground or elevated water tanks to consistently supply drinking water to residents. Online field measurement for Nonsan-2 district meter area demonstrated that intermittent replenishment from large-demand customers could disrupt the normal operation of a water distribution system by taking large quantities of water in short times when filling the tanks from distribution mains. Based on the previous results of field measurement for hydraulic and water quality parameters, statistical analysis is performed for measured data in terms of autocorrelation, power spectral density, and cross-correlation. The statistical results show that the intermittent filling interval of 6.7 h and diurnal demand pattern of 23.3 h are detected through autocorrelation analyses, the similarities of the flow-pressure and the turbidity-particle count data are confirmed as a function of frequency through power spectral density analyses, and a strong cross-correlation is observed in the flow-pressure and turbidity-particle count analyses. In addition, physicochemical results show that the intermittent refill of storage tank from large-demand customers induces abnormal flow and pressure fluctuations and results in transient-induced turbid flow mainly composed of fine particles ranging within 2–4 μm and constituting Fe, Si, and Al

    Mechanisms of Acquired Resistance to AZD9291 A Mutation-Selective, Irreversible EGFR Inhibitor

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    IntroductionAZD9291, a third-generation and mutation-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is active against patients with EGFRT790M-mutant non–small-cell lung cancer (NSCLC) who failed prior treatment with EGFR TKIs. However, acquired resistance to AZD9291 is inevitable. In this study, we identified the mechanisms of acquired resistance to AZD9291 in EGFRT790M-mutant NSCLC.MethodsFour NSCLC patients with both an EGFR exon 19 deletion and the EGFRT790M mutation after developing acquired resistance to first-generation EGFR TKIs received AZD9291 at doses of 20 to 80 mg/day in a phase I trial (NCT01802632). Paired tumor samples before and after treatment were obtained to evaluate EGFR modifications, alternative pathway activation, and histologic transformation. Genetic alterations were analyzed using Sanger sequencing, fluorescence in situ hybridization, real-time polymerase chain reaction, and targeted exome sequencing.ResultsAll four patients achieved a partial response (median duration of response, 9 months [range, 9–11 months]) and subsequently showed resistance to AZD9291. EGFRT790M-mutant clones depopulated AZD9291-resistant tumors to below 1% (baseline, 14%–36%) in three patients with progression: one with the loss of EGFRLREAT747del/T790M-double mutant clones and two accompanied by transformation to small-cell carcinoma and focal fibroblast growth factor receptor 1 (FGFR1) amplification, respectively. EGFRT790M-mutant clones remained and the EGFR ligand was overexpressed in one patient with focal progression to AZD9291.ConclusionAcquired resistance mechanisms of AZD9291 in patients with EGFRT790M-mutant NSCLC who failed treatment with first-generation EGFR TKIs include the loss of EGFRT790M-mutant clones plus alternative pathway activation or histologic transformation and EGFR ligand–dependent activation

    A Critical Heat Generation for Safe Nuclear Fuels after a LOCA

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    This study applies a thermo-elasto-plastic-creep finite element procedure to the analysis of an accidental behavior of nuclear fuel as well as normal behavior. The result will be used as basic data for the robust design of nuclear power plant and fuels. We extended the range of mechanical strain from small or medium to large adopting the Hencky logarithmic strain measure in addition to the Green-Lagrange strain and Almansi strain measures, for the possible large strain situation in accidental environments. We found that there is a critical heat generation after LOCA without ECCS (event category 5), under which the cladding of fuel sustains the internal pressure and temperature for the time being for the rescue of the power plant. With the heat generation above the critical value caused by malfunctioning of the control rods, the stiffness of cladding becomes zero due to the softening by high temperature. The weak position of cladding along the length continuously bulges radially to burst and to discharge radioactive substances. This kind of cases should be avoid by any means
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