2,232 research outputs found

    Domain wall dynamics of the Ising chains in a transverse field

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    We show that the dynamics of an Ising spin chain in a transverse field conserves the number of domains (strings of down spins in an up-spin background) at discrete times. This enables the determination of the eigenfunctions of the time-evolution operator, and the dynamics of initial states with domains. The transverse magnetization is shown to be identically zero in all sectors with a fixed number of domains. For an initial state with a single string of down spins, the local magnetization, the equal-time and double-time spin-spin correlation functions, are calculated analytically as functions of time and the initial string size. The domain size distribution function can be expressed as a simple integral involving Bessel functions.Comment: 4 pages with three figure

    Enhanced photocatalytic and antibacterial activity of plasma-reduced silver nanoparticles

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    A non-thermal atmospheric pressure plasma jet has been used for the green synthesis of highly dispersed colloidal silver nanoparticles. The reducing species such as hydrogen radicals and hydrated electrons are identified, and the change in the solution pH is studied during AgNP formation. The structural properties and size of the plasma-reduced silver nanoparticles are characterized via X-ray diffraction, ultraviolet-visible spectroscopy, fluorescence spectroscopy and transmission electron microscopy. The size of the colloidal AgNPs is tuned by adjusting the initial concentration of AgNO3. The effect of terephthalic acid, a hydroxyl radical scavenger, on the reduction of Ag+ ion is studied. The typical catalytic activity data indicate the better performance of the plasma-reduced colloidal Ag nanoparticles than that obtained from the chemical reduction method. The antibacterial activity of the plasma-reduced Ag nanoparticles also shows a better performance than that of the chemically reduced AgNPs, highlighting the potential of the plasma reduction approach for the synthesis of metal nanoparticles, which are stable even after 30 days without a stabilizing agent. Additionally, the effects of hydroxyl scavengers (isopropyl alcohol) and Fenton's reagent (Fe2+ salt) on CV degradation are studied

    Liquidity and Asset Prices in Multiple Markets

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    Liquidity is generally viewed as a positive characteristic of a traded asset in positive net supply. Ceteris paribus, the higher liquidity of a given asset should be reflected in a higher price or a lower required return. This issue is of particular interest if the same asset is traded in multiple markets. In this setting, apart from the effect of liquidity on pricing in each market, there is the additional question of transmission of these liquidity effects across markets. This paper investigates the liquidity effect in asset pricing by studying the liquidity-premium relationship of an American Depositary Receipt (ADR) and its underlying share in the home market. Using the Amihud (2002) measure, the turnover ratio and trading infrequency as proxies for liquidity, we show that a higher ADR premium is associated with higher ADR liquidity, lower home share liquidity. We measure these effects, in terms of both the levels and changes, in both the premium and the liquidity variables. We find that the liquidity effects remain strong even after we control for firm size and a number of country characteristics, such as the expected change in the foreign exchange rate, the home country and the US stock market performance, as well as several variables measuring the openness and transparency of the home market

    Combustion synthesized TiO2 for enhanced photocatalytic activity under the direct sunlight-optimization of titanylnitrate synthesis

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    Optimized synthesis of Ti-precursor ‘titanylnitrate’ for one step combustion synthesis of N- and C-doped TiO2 catalysts were reported and characterized by using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), diffused reflectance UV–vis spectroscopy, N2 adsorption and X-ray photoelectron spectroscopy (XPS). XRD confirmed the formation of TiO2 anatase and nano-crystallite size which was further confirmed by TEM. UV-DRS confirmed the decrease in the band gap to less than 3.0 eV, which was assigned due to the presence of C and N in the framework of TiO2 as confirmed by X-ray photoelectron spectroscopy. Degradation of methylene blue in aqueous solution under the direct sunlight was carried out and typical results indicated the better performance of the synthesized catalysts than Degussa P-25

    IEEE 802.15.4-PHY Packet Detection and Transmission System With Differential Encoding For Low Power IoT Networks

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    Synchronization is the first operation in a digital base band receiver. The accuracy of the synchronizer shapes up the performance of the base band receiver. Synchronization is broadly divided into Carrier Frequency and Phase Synchronization, Symbol Timing and Frame Synchronization. If number of false detections in frame synchronization are high then large amount of power is wasted for processing unwanted packets. In this paper, we are proposing a packet detection and transmission system with differential encoding for low power IoT networks which reduces the number of false packet detections compared to existing preamble detection techniques. The proposed frame synchronization method decides packet is valid or not by cross correlating received packet with fixed preamble sequence and determine its boundaries. The proposed system is analyzed with smart metering power data and corresponding probabilities of packet missing and false detection, power consumption and bit error rate are analyzed. At 3 dB SNR the number of false detections are reduced by 170 compared to conventional correlation method thereby saving 15.8 % of processing power at receiver

    The Last Great Arbitrage: Exploiting the Buy-and-Hold Mutual Fund Investor

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    This paper demonstrates that an an institutional feature inherent in a multitude of mutual funds managing billions in assets generates fund NAVs that reflect stale prices. Since, in many cases, investors can trade at these NAVs with little or no transactions costs, there is an obvious trading opportunity. Simple, feasible strategies generate Sharpe ratios that are sometimes one hundred times greater than the Sharpe ratio of the underlying fund. These opportunities are especially prevalent in international funds that buy Japanese or European equities and in funds that invest in thinly traded securities in the U.S. When implemented, the gains from these strategies are matched by o setting losses incurred by buy-and-hold investors in these funds. In one particular example, we explore the consequences of trading between different Vanguard mutual funds, motivated via the rules inherent in University 403B plans. Compared to an equal-weighted buy-and-hold portfolio of international Vanguard funds with a 25% cumulative return, the strategy discussed in this paper produces a 139% return while being in the stock market less than 25% of the time

    Catalytic non-thermal plasma reactor for decomposition of dilute chlorobenzene

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    Oxidative decomposition of low concentrations of chlorobenzene (CB) in air was carried out in a NTP reactor. Typical results indicated the better performance on addition of metal oxide catalysts in plasma zone. It may be concluded that catalytic plasma approach has promise, especially for the removal of low concentraions of CB, where conventional techniques are not energetically feasible. Among the metal oxides studied, AgOx/MnOx showed the better performance than MnOx and CoOx. During the removal of 50 ppm of CB, AgOx/MnOx under humid conditions showed 100% selectivity to total oxidadtion at 260 J L-1, which may be assigned due to the formation of hydroxyl radical and/or due to in situ ozone decomposition on the catalyst surface that may lead to the formation of a powerful oxidant atomic oxygen. Oxidative decomposition of low concentrations of chlorobenzene in air was carried out in a NTP reactor. Results indicated the improved performance on addition of catalysts in plasma zone. It has been observed that the integration of metal oxides, promoted the total oxidation, whose activity was further enhanced on addition of water vapor. During the abatement of 50 ppm of CB, selectivity to CO2 was 100% at 260 J L-1 with AgOx/MnOx/SMF catalytic electrode

    Effect of carbon nanofibre addition on the mechanical properties of different Vf carbon-epoxy composites

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    Carbon-epoxy (C-epoxy) laminated composites having different fibre volume fractions (40, 50, 60 and 70) were fabricated with and without the addition of aminofunctionalized carbon nanofibres (A-CNF). Flexural strength, interlaminar shear strength (ILSS) and tensile strength of the composite laminates were determined. It was observed that, the ability of A-CNF to enhance the mechanical properties of C-epoxy diminished significantly as the fibre volume fraction (Vf) of the C-epoxy increased from 40 to 60. At 70Vf, the mechanical properties of the ACNF reinforced C-epoxy were found to be lower compared to the C-epoxy composite made without the addition of A-CNF. In this paper suitable mechanisms for the observed trends are proposed on the basis of the fracture modes of the composite

    人の集団に関する新たな評価方法の考察

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    九州大学応用力学研究所研究集会報告 No.20ME-S7 「非線形波動の数理と物理」RIAM Symposium No.20ME-S7 Mathematics and Physics in Nonlinear waves本研究では、金融工学の手法を用いて人の混雑を評価する理論の構築を試みた。我々は、人の混雑を表すダイナミクスは確率項を含むLogistic 方程式に従うと仮定し、この動きを正味現在価値やリアルオプション法によって評価した。また、金融工学では、割引率を用いることによってタイミングによる価値の違いが表現されるが今回のモデルでは、割引率を人の効用を割り引くために導入し、実データに基づく推定・考察もあわせて行った
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