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Numerical Simulation of Fluid Flow and Heat Transfer in Funnel Shaped Mold of Thin Slab Continuous Caster

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Journal of Iron and Steel Research International 2005年第6期12卷 14-19页

作者： ZHU Miao-yong WANG jun zhang ying Northeastern University Shenyang 110004 China

Thin slab casting is used widely in the world. The control of molten steel flow and solidification in the mold is difficult due to the high casting speed and complicated configuration of the mold. Numerical simulation was carried out to study the fluid flow and heat transfer in the funnel shaped mold. The influence of nozzle design, casting speed and nozzle submersion depth on the flow and temperature fields in the mold was investigated, and guidance for selecting configurations of submerged nozzle was obtained.

关键词： thin slab continuous casting fluid flow heat transfer numerical simulation

Gini Correlation for Feature Screening

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Acta Mathematicae Applicatae Sinica 2021年第3期37卷 590-601页

作者： jun-ying zhang Xiao-feng LIU Ri-quan zhang Hang-WANG Department of Mathematics Taiyuan University of TechnologyTaiyuan 030024China College of Data Science Taiyuan University of TechnologyTaiyuan 030024China School of Finance and Statistics East China Normal UniversityShanghai 200241China Department of Mathematics Shanxi Datong UniversityDatong 037009China

In this paper we propose the Gini correlation screening(GCS)method to select the important variables with ultrahigh dimensional *** new procedure is based on the Gini correlation coefficient via the covariance between the response and the rank of the predictor variables rather than the Pearson correlation and the Kendallτcorrelation *** new method does not require imposing a specific model structure on regression functions and only needs the condition which the predictors and response have continuous distribution *** demonstrate that,with the number of predictors growing at an exponential rate of the sample size,the proposed procedure possesses consistency in ranking,which is both useful in its own right and can lead to consistency in *** procedure is computationally efficient and simple,and exhibits a competent empirical performance in our intensive simulations and real data analysis.

关键词： ultrahigh dimension Gini correlation coefficient variable screening feature ranking

Exact Periodic Solutions to Generalized BBM Equation and Relevant Conclusions

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Acta Mathematicae Applicatae Sinica 2006年第3期22卷 509-516页

作者： jun-ying An Wei-guo zhang University of Shanghai for Science and Technology Shanghai 200093 China

In this paper, we consider generalized BBM equation with nonlinear terms of high *** the case of p=1/2, p=1 and p=2, the exact periodic solutions to G-BBM equation are obtained by means of proper transformation, which degrades the order of nonlinear terms. And we prove that if p ≠ 1/2,p ≠ 1 or p ≠ 2, G-BBM equation does not exist this kind of periodic solution.

关键词： Jacobi elliptic function nonlinear evolution equation periodic solutions

Minor antifungal aromatic glycosides from the roots of Gentiana rigescens(Gentianaceae)

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Chinese Chemical Letters 2009年第10期20卷 1215-1217页

作者： Min Xu Chong Ren Yang ying jun zhang State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of Sciences Kunming 650204 China

Two new phenolic glycosides, 2,3-dihydroxybenzoic acid methyl ester 3-O-β-o-glucopyranosyl-（1-6）-β-D-glucopyranoside （1） and 2,5-dihydroxylbenzofuran 5-O-β-D-xylopyranosyl-（1-6）-O-β-D-glucopyranoside （2）, were isolated as the minor chemical constituents from the roots of Gentiana rigescens, along with 15 known compounds. Their structures were elucidated by detailed spectroscopic analysis, including 1D, 2D NMR and chemical method. All of these compounds were isolated for the first time from the title plant. Moreover, compounds 1 and 2 were tested for the antifungal activities on three plant pathogens Peronophythora litchi, Glomerella cingulata, and Glorosprium musarum.

关键词： Gentiana rigescen Phenolic glycosides Anfifungal activity Plant pathogen

Cross-linked Polyamides Prepared through Direct Bulk Michael Addition and Polycondensation from 1,6-Hexanediamine and Methyl Acrylate

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Chinese Journal of Polymer Science 2020年第2期38卷 143-150,I0006页

作者： Sheng-Qing Yang Jin-Nan Zhao Jing-Bo Zhao Zhi-Yuan zhang jun-ying zhang Key Laboratory of Carbon Fiber and Functional Polymers(Beijing University of Chemical Technology) Ministry of Education/College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

Cross-linked polyamides(c PAs)were prepared through direct bulk Michael addition and subsequent *** mixed hexanediamine multi-esters(HDAMEs)were generated through the Michael addition of 1,6-hexanediamine(HDA)and methyl acrylate(MA)at50℃ with different HDA/MA molar *** polycondensation of HDAMEs then proceeded at 150 or 170℃ in flasks to obtain viscous fluids,and curing was continued in tetrafluoroethylene molds to obtain c PA *** Michael addition was monitored on the basis of FTIR and ESI-MS *** c PA films were characterized by DSC,TGA,dynamic mechanical analysis,and tensile *** directly prepared c PAs exhibited Tg of 1–39℃,tensile strength of up to 45 MPa,and strain at break from 18%to 40%.The c PAs with high tensile strength and good toughness were successfully synthesized through the direct bulk Michael addition from HDA and MA followed with polycondensation.

关键词： Michael addition Polycondensation Mechanical properties

Properties of polydimethylsiloxane hydrophobic modified duplex microarc oxidation/diamond-like carbon coatings on AZ31B Mg alloy

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Journal of Magnesium and Alloys 2021年第4期9卷 1291-1303页

作者： Xue-jun Cui Chuang-Ming Ning Guang-An zhang Lun-Lin Shang Li-Ping Zhong ying-jun zhang School of Materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities Zigong 643000China

A reliable,high-performance coating procedure was developed using PDMS to modify a duplex MAO/DLC coating on an AZ31B Mg ***,the duplex MAO/DLC coating was fabricated via a combined MAO and unbalanced magnetron sputter ***,a PDMS solution was used to modify the MAO/DLC coating via a conventional dip-coating *** surface characteristics,bond strength,hardness,tribological behaviour,and corrosion resistance of the coated samples were evaluated via SEM,CA,Raman spectroscopy,friction and wear behaviour,polarisation curve,and NSS *** PDMS modification reduced the HIT of MAO/DLC coating from 15.96 to 8.34GPa;this is ascribed to the penetration of PDMS,which has good rheological properties to form a viscoelastic Si-based organic polymer layer on the MAO/DLC ***,the PDMS-modified MAO/DLC coating was denser,hydrophobic,and had higher bond strength compared with MAO-and MAO/DLC-coated ***,the PDMS modification reduced the COF and wear rate of the duplex MAO/DLC *** indicates that the PDMS improved the tribological behaviour owing to the transferred Si oxide that originated from the Si-O network of the PDMS,as well as the low graphitisation of the DLC layer during ***,the corrosion current density of the MAO/DLC-coated sample modified by PDMS for 10min decreased by two order of magnitude compared with that of the MAO/DLC-coated sample but by five orders of magnitude compared with that of the bare *** NSS tests proved that the PDMS layer slowed the corrosion of the Mg alloy under long-term service,enhancing the corrosion protection *** results are attributed to the high bond strength and lubricant MAO/DLC layer,and the dual role of sealing and hydrophobicity of ***,PDMS modification is promising for the fabrication of protective materials for Mg alloys that require corrosion and wear resistance.

关键词： Magnesium alloy Microarc oxidation Diamond-like carbon Polydimethylsiloxane Tribological behaviour Corrosion resistance

Reconfigurable Intelligent Surface Assisted D2D Underlay Communications:A Two-Timescale Optimization Design

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Journal of Communications and Information Networks 2020年第4期5卷 369-380页

作者： Chang Cai Huiyuan Yang Xiaojun Yuan ying-jun Angela zhang Yi Liu Center for Intelligent Networking and Communications(CINC) University of Electronic Science and Technology of China(UESTC)Chengdu 611731China Department of Information Engineering The Chinese University of Hong KongHong Kong 999077China

The performance of a device-to-device(D2D)underlay communication system is limited by the co-channel interference between cellular users(CUs)and D2D *** address this challenge,a reconfigurable intelligent surface(RIS)aided D2D underlay system is studied in this paper.A two-timescale optimization scheme is proposed to reduce the required channel training and feedback overhead,where transmit beamforming at the base station(BS)and power control at the D2D transmitters are adapted to instantaneous effective channel state information(CSI);and the RIS phase shifts are adapted to slow-varying channel *** on the two-timescale optimization scheme,we aim to maximize the D2D ergodic weighted sum-rate(WSR)subject to a given outage probability constrained signal-to-interference-plus-noise ratio(SINR)target for each *** two-timescale problem is decoupled into two sub-problems,and the two sub-problems are solved *** results verified that the two-timescale based optimization performs better than two baselines,and also demonstrated a favourable trade-off between system performance and CSI overhead.

关键词： reconfigurable intelligent surface(RIS) device-to-device(D2D)underlay communication twotimescale optimization

Aliphatic Thermoplastic Poly(ether urethane)s Having Long PEG Sequences Synthesized through a Non-isocyanate Route

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Chinese Journal of Polymer Science 2015年第6期33卷 880-889页

作者： Yong Deng Su-qing Li 赵京波 Zhi-yuan zhang jun-ying zhang Wan-tai Yang Key Laboratory of Carbon Fiber and Functional Polymers (Beijing University of Chemical Technology) Ministry of Education State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology

A non-isocyanate route for synthesizing thermoplastic polyurethanes with excellent thermal and mechanical properties was described. Melt transurethane polycondensation of 1,6-bis（hydroxyethyloxy carbonyl amino）hexane with four poly（ethylene glycol）s （PEGs）, i.e. PEG400, PEG600, PEG1000, or PEG1500, was conducted at different molar ratios. A series of thermoplastic poly（ether urethane）s （TPEUs） with long PEG sequences were prepared. The TPEUs were characterized via gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray scattering, and tensile tests. The TPEUs exhibit Tg between 12.4 ℃ and -40.4 ℃, Tm of up to 149.8 ℃, and initial decomposition temperature over 239.4 ℃. The tensile strength of the TPEUs reaches 38.39 MPa with a strain at break of 852.92%.

关键词： Non-isoeyanate route Poly(ether urethane)s Transuretbane polycondensation Diurethanediol Thermoplastic.

Two New Phenolic Constituents from the Stems of Euphorbia griffithii

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Natural Products and Bioprospecting 2019年第6期9卷 405-410页

作者： Joseph Sakah Kaunda ying-jun zhang State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650204People’s Republic of China Graduate School of the Chinese Academy of Sciences Beijing 100039People’s Republic of China Yunnan Key Laboratory of Natural Medicinal Chemistry Kunming Institute of BotanyChinese Academy of SciencesKunming 650201People’s Republic of China

Phytochemical studies on MeOH extract of stems of Euphorbia griffithii led to the isolation of one new hydrolyzable tannin dimer,corilagiffithiin(1)and one new galloyl-glucoside(2),alongside six known ones(3-8).Their structures and absolute configurations were determined by in depth spectroscopic analyses and comparison of their 1D NMR and MS data with literature reported *** of sugar moieties were determined by acidic hydrolysis and subsequent GC analysis of their corresponding trimethylsilylated l-cysteine *** a concentration of 50μM,compounds 1-3 showed no anti-inflammatory activities.

关键词： Euphorbiaceae Euphorbia griffithii Phenolic glycosides Hydrolyzable tannins