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Exploring bouncing cosmologies with cosmological surveys

Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1414-1430页

作者： cai Yi-fu Department of Physics McGill UniversityMontréal QC H3A 2T8 Canada

From recent observational data two significant directions have been made in the field of theoretical cosmology recently. First, we are now able to make use of present observations, such as the Planck and BICEP2 data, to examine theoretical predictions from the standard inflationary ACDM which were made decades of years ago. Second, we can search for new cosmological signatures as a way to explore physics beyond the standard cosmic paradigm. In particular, a subset of early universe models admit a nonsingular bouncing solution that attempts to address the issue of the big bang singularity. These models have achieved a series of considerable developments in recent years, in particular in their perturbative frameworks, which made brand-new predictions of cosmological signatures that could be visible in current and forthcoming observations. Herein we present two representative paradigms of early universe physics. The first is the reputed new matter （or matter-ekpyrotic） bounce scenario in which the universe starts with a matter-dominated contraction phase and transitions into an ekpyrotic phase. In the setting of this paradigm, we have proposed some possible mechanisms of generating a red tilt for primordial curvature perturbations and confront the general predictions with recent cosmological observations. The second is the matter-bounce inflation scenario which can be viewed as an extension of inflationary cosmology with a matter contraction before inflation. We present a class of possible model constructions and review the implications on the current CMB experiments. Lastly a review of significant achievements of these paradigms beyond the inflationary ACDM model is made, which is expected to shed new light on the future direction of observational cosmology.

关键词： bouncing cosmology big bang singularity CMB observations

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Probing the origin of our universe through primordial gravitational waves by Ali CMB project

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Science China(Physics,Mechanics & Astronomy) 2016年第7期59卷 90-92页

作者： Yi-fu cai XinMin Zhang CAS Key Laboratory for Researches in Galaxies and Cosmology Department of Astronomy University of Science and Technology of ChinaChinese Academy of Sciences Theoretical Physics Division Institute of High Energy Physics Chinese Academy of Sciences

Gravitational waves （GW）, which were predicted by Einstein in 1916 based on the classical theory of General Relativ- ity （GR）, were recently detected by LIGO [1]. This break- through is expected to initiate a novel probe of cosmology, the nature of gravity as well as fundamental physics. In general, signals of GWs can be classified into two categories, which are waves from astro-physical and cosmological sources re- spectively. Accordingly, a number of astronomical and cos- mological experiments are under design across the world [2]. In particular, China is playing a very important role in this field by strengthening a series of fundamental scientific sub- iects, such as cosmic evolution, structure of matter,

关键词：宇宙起源引力波招商项目阿里天文物理经典理论爱因斯坦宇宙探测

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SYNTHESIS OF A SILICON-CONTAINING FLAME RETARDANT AND ITS SYNERGISTIC EFFECT WITH POTASSIUM-4-(PHENYLSULFONYL)BENZENESULFONATE(KSS) IN POLYCARBONATE(PC)

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Chinese Journal of Polymer Science 2013年第10期31卷 1352-1358页

作者： Dan-dan Yuan Xu-fu cai Department of Polymer Science and Materials State Key Laboratory of Polymer Materials Engineering Sichuan University

A novel flame retardant （DAPSiO）, containing silicon and nitrogen, was synthesized by using dichlorodiphenylsilane, γchloropropyl methyl dimethoxysilane and 1,2-ethanediamine. DAPSiO was used together with potassium-4-（phenylsulfonyl）benzenesulfonate （KSS） to prepare a flame-retardant system for polycarbonate （PC）. The structure of DAPSiO was characterized by Fourier transform infrared spectroscopy （FTIR）, and 1H-NMR tests. Flammability and thermal behaviors of PC/KSS/DAPSiO systems were estimated by limited oxygen index （LOI）, vertical burning test （UL-94） and thermogravimetric analysis （TGA） tests. The results showed that the flame retardancy and thermal stability of PC/KSS system were improved with the addition of DAPSiO. When 1 wt% DAPSiO and 0.5 wt% KSS were incorporated, the LOI value of PC was found to be 44, and class V-0 of UL-94 test was passed. The scanning electron microscopy （SEM） and FTIR indicated that PC/KSS/DAPSiO system held a more cohesive and denser char structure when compared with pure PC and PC/KSS system.

关键词： Flame retardant Thermal properties Silicon Polycarbonate.

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Effect of Cr on Characteristic of Rust Layer Formed on Low Alloy Steel in Flow-accelerated Corrosion Environment

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Journal of Iron and Steel Research International 2016年第6期23卷 602-607页

作者： Feng CHAI Shan JIANG cai-fu YANG Department of Engineering Steels Central Iron and Steel Research Insititute

The flow-accelerated corrosion experiments were carried out to research the effect of Cr on the rust layers formed on the carbon steel and Cr-containing steel,as well as the structure of rust layer of the two experimental *** influence of Cr on the flow-accelerated corrosion resistance and the corrosion morphology of inner rust layer formed on the Cr-containing steel were studied by the methods of polarization curves,scanning electron microscope,transmission electron microscope,and X-ray photoelectron *** distribution of Cr and its form of existence in the inner rust layer were *** results show that corroded mass loss of Cr-containing steel is lower than that of carbon steel and its inner rust layer is *** exists in the form of Fe2CrO4 and is enriched in the inner rust *** concentration could make the inner rust layer exhibit the tendency of *** phenomenon is related to fine *** inner rust layer becomes more compact because of the formation of fine Fe2CrO4,and the protectiveness of inner rust layer could be improved remarkably.

关键词： accelerated photoelectron amorphous remarkably steels finer enriched cathodic hence attributed

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Generalized Multi-component TC Hierarchy and Its Multi-component Integrable Coupling System

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Communications in Theoretical Physics 2005年第5X期44卷 793-798页

作者： XIA Tie-Cheng YOU fu-cai Department of Mathematics Shanghai University Shanghai 200444 China

A new 3M-dimensional Lie algebra X is constructed firstly. Then, the corresponding loop algebra X is produced, whose commutation operation defined by us is as simple and straightforward as that in the loop algebra *** follows that a generalscheme for generating multi-component integrable hierarchy is proposed. By taking advantage of X, a new isospectral problem is established, and then well-known multi-component TC hierarchy is obtained. Finally,an expanding loop algebra FM of the loop algebra X is presented. Based on the FM, the multi-component integrable coupling system of the generalized multi-component TC hierarchy has been worked out. The method in this paper can be applied to other nonlinear evolution equations hierarchies. It is easy to find that we can construct any finite-dimensional Lie algebra by this approach.

关键词： loop algebra multi-component TC hierarchy multi-component integrable coupling system

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Research,Development,and Production of V-N Microalloyed High Strength Rebars for Building in China

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Journal of Iron and Steel Research International 2008年第2期15卷 81-86页

作者： YANG cai-fu WANG Quan-li Central Iron and Steel Research Institute Beijing 100081 China Capital Iron and Steel Group Company Beijing 100041 China

The research,production,and application of V-N microalloyed high strength rebars in China were *** nitrogen in vanadium-containing rebars promotes the precipitation of fine V（C,N）particles,and markedly improves the precipitation strengthening effectiveness of ***,vanadium added to V-N microalloyed rebars can be reduced by 40% compared to the same strength level of vanadium-containing rebars.

关键词： high strength reinforced bar V-N microalloying precipitation strengthening

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Henry Tye: the future of theoretical physics and advice to young researchers

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National Science Review 2021年第8期8卷 216-219页

作者： Yi-fu cai Sheng-Feng Yan the Department of Astronomy School of Physical SciencesUSTC the National Institute for Nuclear Physics in Milan

Professor Henry Tye(戴自海) is a world-renowned expert in theoretical particle physics, string theory and cosmology. He was recently the IAS Professor at the Jockey Club Institute for Advanced Study(IAS) and the Hong Kong University of Science and Technology(HKUST),and is the Horace White Professor of Physics(Emeritus) at Cornell University. He has a lot of experience in research status in both China and the United States. Recently, NSR invited Professor Yi-fu cai(蔡一夫) from the University of Science and Technology of China(USTC)to interview Prof. Tye on his personal views on the future of theoretical physics, his own experience, and his advice to young researchers.

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Convergence of the Vlasov-Poisson-Boltzmann System to the Incompressible Euler Equations

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Acta Mathematica Sinica,English Series 2007年第4期23卷 761-768页

作者： Ling HSIAO fu cai LI Shu WANG Academy of Mathematics and Systems Science Beijing 100080 P. R Chinese Academy of Sciences China Department of Mathematics Nanjing University Nanjing 210093 P. R. China College of Applied Sciences Beijing University of Technology Beijing 100022 P. R. China

In this paper we establish the convergence of the Vlasov-Poisson-Boltzmann system to the incompressible Euler equations in the so-called quasi-neutral regime. The convergence is rigorously proved for time intervals on which the smooth solution of the Euler equations of the incompressible fluid exists. The proof relies on the relative-entropy method.

关键词： Vlasov-Poisson-Boltzmann system Euler equations of the incompressible fluid Relativeentropy method

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Ni segregation and thermal stability of reversed austenite in a Fe–Ni alloy processed by QLT heat treatment

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Rare Metals 2015年第11期34卷 776-782页

作者： Tao Pan Jing Zhu Hang Su cai-fu Yang Division of Structural Materials Central Iron and Steel Research Institute School of Materials Science and Engineering Tsinghua University

High-resolution transmission electron microscopy(HRTEM) and X-ray diffraction(XRD) were used to investigate Ni segregation and thermal stability of reversed austenite(RA) in a Fe–Ni alloy processed by quench–lamellarize–temper(QLT) heat treatment. The results show that the 77 K impact energy of the alloy increases with RA content increasing. As an austenite-stabilizing element, Ni is found to segregate in RA, though Ni is not evenly distributed within RA. The amount of segregations increases near the boundary(twice as high as the balanced content)and decreases to some extent in the center of the RA regions. Ni concentration in matrix near the boundary is lower than that in matrix far from the boundary because of Ni atom transportation from a to c near the boundary. RA in this alloy has high heat and mechanical stability but is likely to lose its stability and transform to martensite when a mechanical load is applied at ultralow temperatures(77 K), which induces plasticity.

关键词： Reversed austenite Quench–lamellarize–temper Compo

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Uniform Regularity for the Isentropic Compressible Magnetohydrodynamic System

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 410-416页

作者： Ji-shan FAN fu-cai LI GEN NAKAMURA Department of Applied Mathematics Nanjing Forestry UniversityNanjing 210037China Department of Mathematics Nanjing UniversityNanjing 210093China Department of Mathematics Hokkaido UniversitySapporo 060-0810Japan

In this paper we first establish the uniform regularity of smooth solutions with respect to the viscosity coefficients to the isentropic compressible magnetohydrodynamic system in a periodic domain T;.We then apply ou... 详细信息

关键词： isentropic compressible magnetohydrodynamic system uniform regularity

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