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Optimized sintering and mechanical properties of Y-TZP ceramics for dental restorations by adding lithium disilicate glass ceramics

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Journal of Advanced Ceramics 2021年第6期10卷 1326-1337页

作者： ke li Jiancun RAO Congqin NING State key Laboratory of High Performance Ceramics and Superfine Micro structure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China AIM Lab Maryland NanoCenterUniversity of MarylandCollege ParkMD 20742USA The Education Ministry key Lab of Resource Chemistry and Shanghai key Laboratory of Rare Earth Functional Materials Shanghai Normal UniversityShanghai 200234China

The novel dental ceramics can be fabricated at lower temperatures when sol-gel derived lithium disilicate glass ceramics(LDGC)was used as an additive for yttria stabilized tetragonal zirconia polycrystalline(Y-TZP)*** effect of LDGC on the sintering,mechanical,and translucent properties of Y-TZP ceramics was investigated in the present *** results showed that the LDGC additive effectively improved the densification of Y-TZP at 1100℃,which was much lower than the sintering temperature for pure *** sintered at 1100℃,the Y-TZP with 1 wt%LDGC reached a relative density of 95.45%,and prossessed a flexural strength of 482.4 MPa and a fracture toughness of 5.94 ***,its translucency was also ***,the addition of LDGC could result in an escape of yttrium atoms from the grain lattice of zirconia,which induced the tetragonal-monoclinic transformation of zirconia and abnormal growth of monoclinic *** escaped yttrium atoms diffused into the intergranular glass *** results indicated that the novel Y-TZP-LDGC ceramics has a great potential to be used for all-ceramic restorations.

关键词： yttria stabilized tetragonal zirconia polycrystalline(Y-TZP) lithium disilicate glass ceramics(LDGC) sintering mechanical properties dental restoration

Characteristics Analysis of Condensation outside Horizontal Tube Bundles and Novel Condensation Enhancement Method

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Journal of Thermal Science 2022年第3期31卷 934-945页

作者： li Nianqi TIAN ke ke Hanbing ZENG Min WANG Qiuwang key Laboratory of Thermo-Fluid Science and Engineering Ministry of EducationXi’an Jiaotong UniversityXi’an710049China key Lab on Steam Power System Wuhan Second Ship Design and Research InstituteWuhan430025China

Condensation is a phase-change heat-transfer phenomenon crucial in many industries involving latent heat release and mass ***-and-tube condensers are essential contributors to the condensation process,and their tube bundles serve as a ***,the thermal-hydraulic characteristics of condensation in a longitudinal-flow shell-and-tube condenser were investigated *** shell-side longitudinal-flow condensation on the horizontal tube bundles was studied considering inlet flow rate,overheating temperature,and non-condensable *** pressure drops and heat transfer coefficients were subdivided into several components to provide further ***-phase interface behavior analyses were conducted to demonstrate the outcomes with respect to the non-condensable gas layer,vapor quality,and non-condensable gas *** on the thorough quantitative analyses outlined above,the thermal resistance of the condensation on the horizontal tube bundle was *** thermal resistance outside the tube was found to dominate the condensation ***,hexagon clamping baffles(HCBs)were introduced as a novel solution to impair condensate boundary layers and provide perturbations to intensify condensation heat *** results revealed that the HCBs enhanced the total heat transfer coefficients by 8.1%–40.7%while reducing the critical overheating temperature and the threshold ratio between sensible and latent heat.

关键词： shell-and-tube condenser film condensation non-condensable gas thermal resistance analysis

Cohomology of the Universal Enveloping Algebras of Certain Bigraded lie Algebras

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Acta Mathematica Sinica,English Series 2018年第10期34卷 1611-1625页

作者： li Nan ZHONG Hao ZHAO Wen huai SHEN School of Mathematical Sciences South China Normal University Guangzhou 510631 P. R. China Department of Mathematics Yanbian University Yanji 133000 P. R. China

Let p be an odd prime and q = 2（p- 1）. Up to total degree t - s 〈 max（（5p^3 ＋ 6p^2 ＋6p ＋4）q- 10,p^4q}, the generators of H^s,t（U（L））, the cohomology of the universal enveloping algebra of a bigraded lie algebra L, are determined and their convergence is also verified. Furthermore our results reveal that this cohomology satisfies an analogous Poindare duality property. This largely generalizes an earlier classical results due to J. P. May.

关键词： Steenrod algebra Hopf algebra lie algebra spectral sequence stable homotopy groups of sphere

Reynolds number dependence of flow past a shallow open cavity

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Science China(Technological Sciences) 2014年第11期57卷 2161-2171页

作者： CHEN huai ZHONG Qiang WANG XingKui li DanXun State key Laboratory of Hydroscience and Engineering Tsinghua University

Measurements were carried out in a shallow open cavity with particle image velocimetry *** cavity has a lengthto-depth ratio of 4:1,and the upstream inflow conditions include laminar,transient,and turbulent regimes at seven different Reynolds *** measured instantaneous velocities were analyzed through ensemble average,vortex extraction,and proper orthogonal decomposition(POD)to investigate overall flow circulations,Reynolds stress distribution,spanwise vortex population,and the characteristics of the POD *** results reveal distinctive Reynolds number dependence of the cavity flow,*** increase in Reynolds number results in constant migration of the overall circulation,enhancement of Reynolds stress,reduction of correlation between vortex and Reynolds stress,and decrease of fractional energy of the characteristic POD ***,a phenomenological model was proposed to describe various features of cavity flow.

关键词： cavity flow Reynolds number Reynolds stress spanwise vortex particle image velocimetry

Big graph search： challenges and techniques

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Frontiers of Computer Science 2016年第3期10卷 387-398页

作者： Shuai MA Jia li Chunming HU Xuelian liN Jinpeng huai State key Laboratory of Software Development Environment School of Computer Science and Engineering Beihang University Beijing 100191 China

On one hand, compared with traditional rela- tional and XML models, graphs have more expressive power and are widely used today. On the other hand, various ap- plications of social computing trigger the pressing need of a new search paradigm. In this article, we argue that big graph search is the one filling this gap. We first introduce the ap- plication of graph search in various scenarios. We then for- malize the graph search problem, and give an analysis of graph search from an evolutionary point of view, followed by the evidences from both the industry and academia. After that, we analyze the difficulties and challenges of big graph search. Finally, we present three classes of techniques to- wards big graph search： query techniques, data techniques and distributed computing techniques.

关键词： graph search big data query techniques data techniques distributed computing

Cosmological implications of a B−L charged hidden scalar:leptogenesis and gravitational waves

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Chinese Physics C 2021年第11期45卷 45-59页

作者： ligong Bian Wei Cheng huai-ke Guo Yongchao Zhang Department of Physics Chongqing UniversityChongqing 401331China Chongqing key Laboratory for Strongly Coupled Physics Chongqing 401331China School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China CAS key laboratory of theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190ChinaUniversity of Chinese Academy of SciencesBeijing 100190China Department of Physics and Astronomy University of OklahomaNormanOK 73019USA School of Physics Southeast UniversityNanjing 211189China Department of Physics and McDonnell Center for the Space Sciences Washington UniversitySt.LouisMO 63130USA Center for High Energy Physics Peking UniversityBeijing 100871China

In this study,we investigated the cosmological implications of a complex singlet scalar S with non-trivial B−L charges in the conformal U(1)B−L *** was found that,in a sizable region of parameter space,S may disturb the resonant leptogenesis mechanism,which is used to generate baryon asymmetry,and affect the symmetry breaking dynamics in the strong first order phase *** stochastic gravitational waves(GWs)produced at the phase transition can be probed in future GW *** GW searches prefer a relatively light S at the TeV-scale;however,this is difficult to detect directly at future high-energy colliders.

关键词： leptogenesis first-order phase transition gravitational wave

Numerical study of collection efficiency and heat-transfer characteristics of packed granular filter

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Particuology 2019年第5期17卷 75-82页

作者： Junlin Chen Xunfeng li Xiulan huai Yongwei Wang Jingzhi Zhou Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

The collection mechanism and heat-transfer characteristics of a packed granular filter were investigated using a three-dimensional randomly packed granular filter model. The bridging method was introduced to optimize the grids of contact points between granules. The influences of granular bed depth, gas velocity, and gas temperature on grade collection efficiency were investigated. The results indicated that a decrease of temperature improved collection efficiency when the particle diameter was greater than 5 |xm. The grade collection efficiency maintained a stable value when the Stokes number, St, was less than 0.009, but increased linearly with ig(St) when St > 0.009. A logarithmic mean temperature difference method was used to obtain overall heat-transfer coefficients of gas-solid two-phase flow through the packed granular filter. The results showed that convective heat transfer was enhanced due to the intro-duction of solid particles in the bed. The overall heat-transfer coefficient increased approximately linearly with an increase in particle loading ratio. The Nusselt number was related to the Reynolds number, the Archimedes number, and the particle loading ratio.

关键词： Packed granular filter Gas-solid two-phase flow Grade collection efficiency Heat transfer

Homotopy Exponents of Stiefel Manifolds in the Stable Range

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Acta Mathematica Sinica,English Series 2016年第9期32卷 1080-1088页

作者： Hao ZHAO li Nan ZHONG Wen huai SHEN School of Mathematical Sciences South China Normal University Guangzhou 510631 P. R. China Department of Mathematics Yanbian University Yanji 133000 P. R. China

Let p be an odd prime. For the Stiefel manifold Wm＋k,k = SU（m ＋ k）/SU（m）, we obtain an upper bound of its p-primary homotopy exponent in the stable range k ≤ m with k ≤ （p - 1）2 ＋ 1.

关键词： Stiefel manifold homotopy exponent H-space

Structure and magnetic properties of NiCuZn ferrite materials with La doping

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Rare Metals 2017年第3期36卷 202-204页

作者： Yuan-Xun li Jie li Qiang li Guo-liang Yu huai-Wu Zhang State key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054China Institute of Electronic and Information Engineering in Dongguan University of Electronic Science and Technology of ChinaDongguan 523808China

Ni0.3Cu0.07Zn0.63Fe2-xLaxO4 ferrites were prepared by solid phase method and sintered at 1,150 ℃ for 6 *** phase formation,microstructure,and magnetic properties of samples were *** doping of La3＋,the samples contain two phases：LaFeO3 and NiCuZn *** electron microscope （SEM） image shows that La doping constrains the growth of NiCuZn ferrite,which is more *** doping improves magnetic properties of NiCuZn ferrite when x ≤ *** saturation magnetization （Ms） increases first;when x =0.03,the highest value is 75.35 *** permeability increases to the maximum value with frequency and then decreases with the concentration of La3＋ *** x =0.03,the maximum value of real permeability at 1 MHz is 333.5,and the loss angle tangent （tanδ） is not more than *** doping improves the properties of NiCuZn ferrite,which can be applied to low-frequency filters.

关键词： NiCuZn ferrite La doping Properties