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Search Results: 1 - 10 of 58727 matches for " Xiao-Chuan Chang "
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The diffuse gamma-ray flux associated with sub-PeV/PeV neutrinos from starburst galaxies
Xiao-Chuan Chang,Xiang-Yu Wang
Physics , 2014, DOI: 10.1088/0004-637X/793/2/131
Abstract: One attractive scenario for the excess of sub-PeV/PeV neutrinos recently reported by IceCube is that they are produced by cosmic rays in starburst galaxies colliding with the dense interstellar medium. These proton-proton ($pp$) collisions also produce high-energy gamma-rays, which finally contribute to the diffuse high-energy gamma-ray background. We calculate the diffuse gamma-ray flux with a semi-analytic approach and consider that the very high energy gamma-rays will be absorbed in the galaxies and converted into electron-position pairs, which then lose almost all their energy through synchrotron radiation in the strong magnetic fields in the starburst region. Since the synchrotron emission goes into energies below GeV, this synchrotron loss reduces the diffuse high-energy gamma-ray flux by a factor of about two, thus leaving more room for other sources to contribute to the gamma-ray background. For a $E_\nu^{-2}$ neutrino spectrum, we find that the diffuse gamma-ray flux contributes about 20% of the observed diffuse gamma-ray background in the 100 GeV range. However, for a steeper neutrino spectrum, this synchrotron loss effect is less important, since the energy fraction in absorbed gamma-rays becomes lower.
Star-forming galaxies as the origin of the IceCube PeV neutrinos
Xiao-Chuan Chang,Ruo-Yu Liu,Xiang-Yu Wang
Physics , 2014, DOI: 10.1088/0004-637X/805/2/95
Abstract: Star-forming galaxies, due to their high star-formation rates and hence large number of supernova remnants therein, are huge reservoirs of cosmic rays (CRs). These CRs collide with gases in the galaxies and produce high-energy neutrinos through $pp$ collisions. In this paper, we calculate the neutrino production efficiency in star-forming galaxies by considering realistic galaxy properties, such as the gas density and galactic wind in star-forming galaxies. To calculate the accumulated neutrino flux, we use the infrared luminosity function of star-forming galaxies obtained by {\em Herschel} PEP/HerMES survey recently. The intensity of CRs producing PeV neutrinos in star-forming galaxies is normalized with the observed CR flux at EeV ({1\,EeV=$10^{18}\,$eV}), assuming that supernova remnants or hypernova remnants in star-forming galaxies can accelerate protons to EeV energies. Our calculations show that the accumulated neutrino emission produced by CRs in star-forming galaxies can account for the flux and spectrum of the sub-PeV/PeV neutrinos under reasonable assumptions on the CR confinement time in these galaxies.
Character First
Xiao-chuan REN
Cross-Cultural Communication , 2010, DOI: 10.3968/784
Abstract: The fundamental task of education is to cultivate talents. Our students are supposed to acquire knowledge and more importantly they should learn to be people with good character. Focusing on the cultivation of students’ moral development and stimulation of their high self-discipline are the cornerstones of their life. In the current waves of globalization, good character can direct to a meaningful and fruitful life. Key words: character; education; cultivation Résumé: La tache fondamentale de l'éducation est de cultiver les talents. Nos élèves sont censés de pourvoir acquérir des connaissances et, surtout, ils devraient apprendre à être des gens avec un bon caractère. L'accent mis sur la cultivation du développement moral des élèves et la stimulation d'une haute autodiscipline sont les pierres de soubassement de leur vie. Dans la vague actuelle de mondialisation, un bon caractère peut les diriger vers une vie significative et fructueuse. Mots-Clés: caractère; education; cultivation
How to Practice Servant Leadership
Xiao-chuan REN
Studies in Literature and Language , 2010,
Abstract: As the focus has changed from the teacher to the learner and the teaching patterns emphasize the cultivation of learners’ learning abilities rather than simply teaching skills and knowledge, the teachers’ teaching capacity or leadership is of particular importance. This article deals with a new leading style: servant-leadership, and explores some applications in English teaching. Key words: servant-leadership; education; practice
A Study of Principles of Bible Translation from the Perspective of Martin Luther’s Bible Translation
Xiao-chuan REN
Canadian Social Science , 2008,
Abstract: This article deals with principles of Bible translation and highlights Martin Luther’s Bible translation. Before Martin Luther’s German Bible, Bible translations were characterized by theological translation. The translators treated the text with reverence and great caution for fear of distorting the meaning of the Bible. Their translations aimed at formal equivalence where the faithfulness to the text was the first priority. Beginning with Martin Luther’s translation, the translators emphasized the readers’ response and stressed the importance of translating into intelligible language. The translators also tended to adopt sense-for-sense translation so that the readers could fully understand the translation and get hold of the essence of the Bible. Key words: Bible translation, Martin Luther, principles Résumé: Cet article étudie la traduction de la Bible par Martin Luther comme le cas pariculier, ananlyse le principe de traduction de la Bible. Les précédentes traductions de la Bible avant Martin Luther sont faits à visage théologique. Les traducteurs en face des mots sacré, avec l’attitude prudente, pieuse et de respect, s'effor aient d’être fidèle au texte de la Bible et cherchait l’égalité de la forme de par crainte de s'écarter de ses intentions originales. A partir de Martin Luther, la traduction se concentre sur la réaction du lecteur. L'accent étant mis en lecture, la langue de la traduction est plus facile à comprendre par les lecteur. La paraphrase est adoptée comme la technique de traduction, afin que les lecteurs comprennent complètement le texte traduit à saisir l'essence spirituelle de la Bible. Mots-Clés: traduction de la Bible, Martin Luther, Principe
Death and Immortality: the Everlasting Themes
Xiao-chuan REN
Canadian Social Science , 2009,
Abstract: The themes of death and eternity impenetrate most of Emily Dickinson's poems. This paper will analyze and appreciate one of her famous poems--- “Because I could not stop for death” to help readers achieve better understanding of the themes. Key words: death; eternity; immortality Résumé: La plupart des poèmes d’Emily Dickenson ont pour thème la mort et l'éternité. Dans cet article, nous allons analyser l’un de ses plus célèbres poèmes - Parce que je ne pouvais pas m’arrêter pour la mort à fin d’aider les lecteurs à mieux comprendre ce thème. Mots-Clés: mort; éternité; immortalité


中国物理 B , 1993,
Abstract: We have investigated doped MBE GaAs films using photoreflectance (PR) spec-troscopy. Special spectral structures have been observed in the vicinity of the funda-mental band gap, which are quite different from the Franz-Keldysh oscillation (FKO) from uniform electric fields under flatband modulations. Numerical analysis has been performed for FKO from electric fields in the space charge region under non-flatband modulations. Some typical FKO line shapes are illustrated. For moderately doped samples the calculated line shapes are basically consistent with experiments. The surface electric field and the Fermi level pinning have also been deduced from exper-iments.
Symplectic Analytical Solutions for the Magnetoelectroelastic Solids Plane Problem in Rectangular Domain
Xiao-Chuan Li,Wei-An Yao
Journal of Applied Mathematics , 2011, DOI: 10.1155/2011/165160
Abstract: The transversely isotropic magnetoelectroelastic solids plane problem in rectangular domain is derived to Hamiltonian system. In symplectic geometry space with the origin variables—displacements, electric potential, and magnetic potential, as well as their duality variables—lengthways stress, electric displacement, and magnetic induction, on the basis of the obtained eigensolutions of zero-eigenvalue, the eigensolutions of nonzero-eigenvalues are also obtained. The former are the basic solutions of Saint-Venant problem, and the latter are the solutions which have the local effect, decay drastically with respect to distance, and are covered in the Saint-Venant principle. So the complete solution of the problem is given out by the symplectic eigensolutions expansion. Finally, a few examples are selected and their analytical solutions are presented.
ZnO-Based Transparent Thin-Film Transistors with MgO Gate Dielectric Grown by in-situ MOCVD

ZHAO Wang,DONG Xin,ZHAO Long,SHI Zhi-Feng,WANG Jin,WANG Hui,XIA Xiao-Chuan,CHANG Yu-Chun,ZHANG Bao-Lin,DU Guo-Tong,

中国物理快报 , 2010,
Optimization for set-point values in secondary cooling process with disturbance on job arriving time

LUO Xiao-chuan,

控制理论与应用 , 2012,
Abstract: Continuous caster is a machine in which the molten steel is solidified to slabs by spraying on it the cooling water. Nonlinear partial differential equations (PDE) of heat conduction cannot accurately describe the physical process, because of the uncertainties in molten steel temperature and ingredient, and the machine status that causes the variation in arriving time of the next job. Therefore, the optimal set-point values of the caster speed and the cooling water flow-rate are difficult to be determined. In practical industrial plants, those values are given by operators based on the look-up-table method which can not ensure the optimal efficiency and quality of slabs. By considering several operation performance functions and operation constraints, we present an optimal operation set-point model and develop an algorithm based on the genetic algorithm framework using weighted performance functions and central difference method. This model and algorithm are validated in experimental tests with real industrial data. In comparison with the look-up-table method, experimental results show that our method provides better operation set-point values which improve the production efficiency and slab quality.
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