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Studies on the Structure and Properties of Multiphase Al_2O_3 Abrasion-resistant Ceramics

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Chinese Journal of Structural Chemistry 2006年第7期25卷 805-810页

作者： WU ren-Ping yu Yan RUAN yu-Zhong College of Materials Science and Engineering Fuzhou University Fuzhou 350002 China

The Al2O3 abrasion-resistant ceramics is successfully prepared by using waste aluminum sludge as the main raw material with the addition of a little clay, talc and barium carbonate. The crystal structure and microstructure of ceramic are characterized by means of XRD, SEM, etc., and the physical and mechanical properties are also tested. The results show that besides the phase of corundum, a little mullite, Mg-Al spinel and hyalophane phases also exist in the product. These phases are produced via reaction in-situ, which can inhibit the overgrowth of Al2O3 grain in grain boundary, and improve the integral property of the material.

关键词： Al2O3 ceramic crystal structure property in-situ synthesis

Flow and transport simulation of Madeira River using three depth-averaged two-equation turbulence closure models

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Water Science and Engineering 2012年第1期5卷 11-25页

作者： Li-ren yu Environmental Software and Digital Visualization(ESDV) Sao Carlos 13561-120Brazil Association of United Schools-Higher Education Center of Sao Carlos(ASSER-CESUSC) Sao Carlos 13574-380Brazil

This paper describes a numerical simulation in the Amazon water system, aiming to develop a quasi-three-dimensional numerical tool for refined modeling of turbulent flow and passive transport of mass in natural waters. Three depth-averaged two-equation turbulence closure models, k-ε,k-w, and k-w, were used to close the non-simplified quasi-three-dimensional hydrodynamic fundamental governing equations. The discretized equations were solved with the advanced multi-grid iterative method using non-orthogonal body-fitted coarse and fine grids with collocated variable arrangement. Except for steady flow computation, the processes of contaminant inpouring and plume development at the beginning of discharge, caused by a side-discharge of a tributary, have also been numerically investigated. The three depth-averaged two-equation closure models are all suitable for modeling strong mixing turbulence. The newly established turbulence models such as the k-w model, with a higher order of magnitude of the turbulence parameter, provide a possibility for improving computational precision.

关键词： river modeling," numerical modeling contaminant transport," depth-averaged turbulence models multi-grid iterative method

Cohomology Theories in Triangulated Categories

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Acta Mathematica Sinica,English Series 2016年第11期32卷 1377-1390页

作者： Wei ren ren yu ZHAO Zhong Kui LIU School of Mathematical Sciences Fudan University Shanghai 200433 P. R. China Department of Mathematics Northwest Normal University Lanzhou 730070 P. R. China

Let C be a triangulated category with a proper class g of triangles. We prove that there exists an Avramov-Martsinkovsky type exact sequence in g, which connects ε-cohomology, ε-Tate cohomology and ε-Corenstein coh... 详细信息

关键词： Triangulated categories proper class of triangles cohomology theories

Through-Thickness Texture Gradient in Hot-Rolled 25Mn-2.5Si-2Al TWIP Steel

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Journal of Iron and Steel Research International 2013年第4期20卷 46-53页

作者： SU yu LI Lin FU ren-yu Department of Materials Science and Engineering Shanghai University

Texture is one of the important factors affecting sheet metal forming *** through-thickness texture gradient during the hot-rolling process of twinning induced plasticity（TWIP）steel sheet was investigated using electron backscatter diffraction and X-ray *** increasing reduction of the TWIP steel,the fraction of∑1 decreased,whereas the fractions of∑3,∑9,and∑*** 53%reduction,a similar trend could be found from its surface to the *** gradients of intensities of the fibers decreased with increasing hot-rolling *** intensities of face-centered cubic（fcc）shear textures E and Y were higher in the center than that at the surface for both *** 20% reduction,the intensity of fcc plain strain texture S orientation increased from the center to the surface.

关键词： twinning induced plasticity steel texture grain boundary character twinning

Comprehensive evaluation of surface air temperature reanalysis over China against urbanization-bias-adjusted observations

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Advances in Climate Change Research 2021年第6期12卷 783-794页

作者： ZHANG Si-Qi ren Guo-yu ren yu-yu ZHANG Ying-Xian XUE Xiao-Ying Department of Atmospheric Science School of Environmental StudiesChina University of GeosciencesWuhan430074China Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing100081China Key Laboratory for Cloud Physics China Meteorological AdministrationBeijing100081China

The reanalysis datasets (CRA40) have now been developed in China Meteorological Administration. We aim to compare the differences in surface air temperature (SAT) between observational that has been adjusted for urbanization bias and reanalysis data (NCEPV1, NCEPV2, ERA5, CFSR, MERRA, JRA55, 20CRV3 and CRA40) over China's Mainland during 1961–2015. The main results are presented as follows. The correlation and standard deviation between the reanalysis data and observations exhibit highly consistent interannual variability and dispersion, with the interannual SAT variability in JRA55 being closest to the observations for 1961–2015 and that of ERA5 for 1979–2015;the dispersions of 20CRV3 is most consistent with the observations for 1961–2015 and that of NCEPV1 for 1979–2015. Although annual mean SAT of the reanalysis is generally 0–2.0 ℃ lower than the observations, the bias in the SAT climatology of 20CRV3 is the least for 1961–2015 in all reanalysis datasets and that of CRA40 is the least for 1979–2015. The trends of NCEPV1 is closer to the observations than other reanalysis for 1961–2015 and that of 20CRV3 for 1979–2015. The biases in terms of interannual variability, dispersion, climatology, and linear trend are increase with altitude. Overall, in terms of the similarity of multiple measures to the urbanization bias-adjusted observations, JRA55 and CRA40 show the best performances for the periods 1961–2015 and 1979–2015 respectively in reproducing various aspects of climatological and climate change features in China's Mainland.

关键词： Temperature Reanalysis data Urbanization bias Adjusted observations Comparison Evaluation China

SWIFT J1749.4-2807: A neutron or quark star?

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Research in Astronomy and Astrophysics 2010年第9期10卷 815-820页

作者： Jun-Wei yu ren-Xin Xu School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China

We investigate a unique accreting millisecond pulsar with X-ray eclipses, SWIFT J1749.4-2807 （hereafter J1749）, and try to set limits on the binary system by various methods including use of the Roche lobe, the mass-radius relations of both main sequence （MS） and white dwarf （WD） companion stars, as well as the measured mass function of the pulsar. The calculations are based on the assumption that the radius of the companion star has reached its Roche radius （or is at 90%）, but the pulsar＇s mass has not been assumed to be a certain value. Our results are as follows. The companion star should be an MS one. For the case that the radius equals its Roche one, we have a companion star with mass M ≈ 0.51 Me and radius Rc ≈ 0.52 R⊙, and the inclination angle is i ≈ 76.5°; for the case that the radius reaches 90% of its Roche one, we have M ≈ 0.43M⊙, Rc ≈ 0.44R⊙ and i ≈ 75.7°. We also obtain the mass of J1749, Mp ≈ 1 M⊙, and conclude that the pulsar could be a quark star if the ratio of the critical frequency of rotation-mode instability to the Keplerian one is higher than - 0.3. The relatively low pulsar mass （about - M⊙） may also challenge the conventional recycling scenario for the origin and evolution of millisecond pulsars. The results presented in this paper are expected to be tested by future observations.

关键词： X-rays binaries i binaries eclipsing -- pulsars general -- pulsars individual SWIFT J1749.4-2807

Sharp estimates for Hübner’s upper bound function with applications

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Applied Mathematics(A Journal of Chinese Universities) 2010年第2期25卷 227-235页

作者： QIU Song-Liang ren Liang-yu School of Science Zhejiang Sci-Tech University Hangzhou 310018 China

New better estimates, which are given in terms of elementary functions, for the function r →（2/π）（1 -r2）κ（r）κ′（r）＋ logr appearing in Hubner＇s sharp upper bound for the Hersch-Pfluger distortion function are obtained. With these estimates, some known bounds for the Hersch-Pfluger distortion function in quasiconformal theory are improved, thus. improving the explicit quasiconformal Schwarz lemma and some known estimates for the solutions to the Ramanujan modular equations.

关键词： Estimate Hubner's inequality Hersch-Pfluger distortion function quasiconformal Schwarz lemma modular equation.

Crystalline mesoporous transition metal oxides： hard-templating synthesis and application in environmental catalysis

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Frontiers of Environmental Science & Engineering 2013年第3期7卷 341-355页

作者： Zhen MA Bei ZHOU yu ren Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAp3) Department of Environmental Science and Engineering Fudan University Shanghai 200433 China Energy Storage Center National Institute of Clean-and-Low-Carbon Energy Shenhua Group Future Science and Technology City Beijing 102209 China

Mesoporous silicas such as MCM-41 and SBA-15 possess high surface areas, ordered nanopores, and excellent thermal stability, and have been often used as catalyst supports. Although mesoporous metal oxides have lower surface areas compared to mesoporous silicas, they generally have more diversified functionalities. Mesopor- ous metal oxides can be synthesized via a soft-templating or hard-templating approach, and these materials have recently found some applications in environmental cata- lysis, such as CO oxidation, N20 decomposition, and elimination of organic pollutants. In this review, we summarize the synthesis of mesoporous transition metal oxides using mesoporous silicas as hard templates, high- light the application of these materials in environmental catalysis, and furnish some prospects for future develop- ment.

关键词： Keywords mesoporous materials silica metal oxide,hard-templating environmental catalysis

Analysis of p53 and vascular endothelial growth factor expression in human gallbladder carcinoma for the determination of tumor vascularity

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World Journal of Gastroenterology 2006年第3期12卷 415-419页

作者： yu Tian ren-yu Ding Ying-Hui Zhi ren-Xuan Guo Shuo-Dong Wu Department of General Surgery Second Affiliated Hospital China Medical University Shenyang110004 Liaoning Province China Department of General Surgery First Affiliated Hospital China Medical University Shenyang110001 Liaoning Province China Department of General Surgery Affiliated BeijingTiantan Hospital Capital University of Medical Sciences Beijing100050 China

AIM： To examine the expression of p53 and vascular endothelial growth factor （VEGF） as well as microvessel count （MVC） and to investigate the role of VEGF as an angiogenic marker and the possible role of p53 in the regulation of angiogenesis in human gallbladder carcinoma. METHODS： Surgically resected specimens of 49 gallbladder carcinomas were studied by immunohistochemical staining for p53 protein, VEGF, and factor VIII-related antigen. VEGF expression and mutant p53 expression were then correlated with Nevin stage, differentiation grade, MVC, and lymph node metastasis. RESULTS： Positive p53 protein and VEGF expressions were found in 61.2% and 63.3% of tumors, respectively. p53 and VEGF staining status was identical in 55.1% of tumors. The Nevin staging of p53- or VEGF-positive tumors was significantly later than that of negative tumors. The MVC in p53- or VEGF-positive tumors was significantly higher than that in negative tumors, and MVC in both p53- and VEGF-negative tumors was significantly lower than that in the other subgroups. CONCLUSION： Our findings suggest that pS3-VEGF pathway can regulate tumor angiogenesis in human gallbladder carcinoma. Combined analysis of p53 and VEGF expression might be useful for predicting the tumor vascularity of gallbladder cancer.

关键词： Gallbladder neoplasms Protein p53 Neovascularization, Pathology