4,835 research outputs found

    Fermions Tunneling from Higher-Dimensional Reissner-Nordstr\"om Black Hole: Semiclassical and Beyond Semiclassical Approximation

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    Based on semiclassical tunneling method, we focus on charged fermions tunneling from higher-dimensional Reissner-Nordstr\"{o}m black hole. We first simplify the Dirac equation by semiclassical approximation, and then a semiclassical Hamilton-Jacobi equation is obtained. Using the Hamilton-Jacobi equation, we study the Hawking temperature and fermions tunneling rate at the event horizon of the higher-dimensional Reissner-Nordstr\"{o}m black hole spacetime. Finally, the correct entropy is calculation by the method beyond semiclassical approximation.Comment: 7 page

    LEARNING BY TEACHING: Action Research into Changes in Metalearning Capacity of Taiwanese Secondary School Students

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    This is an action-based study, aiming to investigate the design, implementation, and evaluation of a pedagogical innovation intended to encourage the development of metalearning capacity in Taiwanese secondary school students. Even though the customary approaches to learning may boost performance in examinations, the students may have also established ignorance of themselves as learners and of the appropriateness of various learning strategies in different situations. In order to develop students into lifelong and self-directed learners, it is valuable to promote their awareness of their learning processes in different contexts and encourage them to take control over their learning strategy selection and deployment (Biggs, 1985). The innovative program was a year long English as a foreign language (EFL) elective course in a Taiwanese secondary school, developed and field-tested through a two-cycle action research project. The participants were grade 10 students (12 in the first cycle and 15 in the second) who took full part in the program. The first-round study collected data mainly from the students’ reflective journals; the second-round study involved additional data sources, including a semi-structured interview and an open-ended questionnaire. Qualitative content analysis, using the coding schemes modeled after previous literature, was adopted to examine the data. This study suggests the principles to facilitate the development of students’ metalearning capacity, namely engaging students in counter-normative role-taking experience, guiding them towards a deeper level of reflection, and building reciprocal interactions among students and between students and teachers. Resistance to this process of transformation might be related to the contextual culture in which the innovative program was situated, and could possibly be addressed by encouraging a change in teacher role and responsibility as well as in overall school climate

    Lifshitz spacetimes, solitons, and generalized BTZ black holes in quantum gravity at a Lifshitz point

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    In this paper, we study static vacuum solutions of quantum gravity at a fixed Lifshitz point in (2+1) dimensions, and present all the diagonal solutions in closed forms in the infrared limit. The exact solutions represent spacetimes with very rich structures: they can represent generalized BTZ black holes, Lifshitz space-times or Lifshitz solitons, in which the spacetimes are free of any kind of space-time singularities, depending on the choices of the free parameters of the solutions. We also find several classes of exact static non-diagonal solutions, which represent similar space-time structures as those given in the diagonal case. The relevance of these solutions to the non-relativistic Lifshitz-type gauge/gravity duality is discussed.Comment: revtex4, 5 figures. Typos are correcte

    Development of rheometer for semi-solid highmelting point alloys

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    A rheometer for semi-solid high-melting point alloys was developed based on the principle of a double-bucket rheometer, with which the solidifying of semi-solid high-melting point alloy melt could be effectively controlled by the control of temperature and the outer force-field; and different microstructures have also been obtained. This rheometer can be used to investigate the rheological behavior under different conditions by changing the Theological parameters. By way of full-duplex communication between the computer and each sensor, automatic control of the test equipment and real- timemeasurement of rheological parameters were realized. Finally, the influencing factors on torque are also quantitatively analyzed

    Probing Transverse Momentum Broadening via Dihadron and Hadron-jet Angular Correlations in Relativistic Heavy-ion Collisions

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    Dijet, dihadron, hadron-jet angular correlations have been reckoned as important probes of the transverse momentum broadening effects in relativistic nuclear collisions. When a pair of high-energy jets created in hard collisions traverse the quark-gluon plasma produced in heavy-ion collisions, they become de-correlated due to the vacuum soft gluon radiation associated with the Sudakov logarithms and the medium-induced transverse momentum broadening. For the first time, we employ the systematical resummation formalism and establish a baseline calculation to describe the dihadron and hadron-jet angular correlation data in pppp and peripheral AAAA collisions where the medium effect is negligible. We demonstrate that the medium-induced broadening ⟨p⊥2⟩\langle p_\perp^2\rangle and the so-called jet quenching parameter q^\hat q can be extracted from the angular de-correlations observed in AAAA collisions. A global χ2\chi^2 analysis of dihadron and hadron-jet angular correlation data renders the best fit ⟨p⊥2⟩∼13 GeV2\langle p_\perp^2 \rangle \sim 13~\textrm{GeV}^2 for a quark jet at RHIC top energy. Further experimental and theoretical efforts along the direction of this work shall significantly advance the quantitative understanding of transverse momentum broadening and help us acquire unprecedented knowledge of jet quenching parameter in relativistic heavy-ion collisions.Comment: 6 pages, 3 figure

    HOW TO IMPROVE THE HACCP SYSTEM IN AN INTERNATIONAL TOURIST HOTEL GROUP? CAUSE-AND -EFFECT ANALYSIS AND PDCA APPLICATION

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    The aim of this study is to discuss not only what the difficulties are to be confronted when a HACCP is introduced into international tourist hotels, but also how to apply effective solutions to overcome these crucial issues.  In-depth interviews were applied in this study to analyze the case of Taiwan’s X international tourist hotels. Based on the outcomes of interviews, a fish-bone diagram was carried out to analyze the practical difficulties encountered in implementing the HACCP system. Next, with the results of the cause and effect analysis, strategies for different problems were developed according to the interviewee’s points of view. PDCA analysis is used repeatedly to develop strategies and recommendations. In comparison to current literature that only provides piecemeal exploration of the difficulties of introducing the HACCP system and the effectiveness of implementing HACCP, this study takes an entire system view into consideration and enables further practical analysis and solutions.
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