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Simulation of the neck growth of non-isometric biosphere during initial sintering

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 263-274页

作者： Jixiang DU shuhua LIANG Xianhui wang Zhikang FAN Department of Material Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 China

Because powders are mostly non-isometric during the sintering process, copper powders were chosen to study the effects of four material transport mechanisms, including surface diffusion, grain-boundary diffusion, volume diffusion, and multi-couplings. These material transport mechanisms were studied with respect to sintering neck growth of a non-isometric biosphere during initial sintering. The evolution of the neck growth in the four transport mechanisms was simulated by Visual C＋＋ as well based on the model of different particles. The results show that the increase of the sintering temperature, both the grain-boundary diffusion and volume diffusion play primary roles in neck growth, while surface diffusion gradually becomes the secondary mechanism. Both the sintered neck and the shrinkage of the two centers increase with increasing temperature by means of the coupling diffusion mechanism. The radius of the sintering neck decreased, and the shrinkage rate of the two centers increased with an increase of the diameter ratio of the two spheres.

关键词： Sintering simulation Non-isometric biosphere model Diffusion mechanism Sintering neck

LEARNING RATES OF KERNEL-BASED ROBUST CLASSIFICATION

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Acta Mathematica Scientia 2022年第3期42卷 1173-1190页

作者： shuhua wang Baohuai SHENG School of Information Engineering Jingdezhen Ceramic UniversityJingdezhen 333403China Department of Finance Zhejiang Yuexiu UniversityShaoxing 312030China Department of Applied Statistics Shaoxing UniversityShaoxing 312000China

This paper considers a robust kernel regularized classification algorithm with a non-convex loss function which is proposed to alleviate the performance deterioration caused by the outliers.A comparison relationship between the excess misclassification error and the excess generalization error is provided;from this,along with the convex analysis theory,a kind of learning rate is *** results show that the performance of the classifier is effected by the outliers,and the extent of impact can be controlled by choosing the homotopy parameters properly.

关键词： Support vector machine robust classification quasiconvex loss function learning rate right-sided directional derivative

Fabrication of ZnS/CdS Heterojunction by Using Bimetallic MOFs Template for Photocatalytic Hydrogen Generation

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Chemical Research in Chinese Universities 2020年第6期36卷 1032-1038页

作者： ZHU Yuxin JIANG Xing LIN Lin wang shuhua CHEN Chao Key Laboratory of Jiangxi Province for Environment and Energy Catalysis College of ChemistryNanchang UniversityNanchang 330031 P.R.China

A new ZnS/CdS heterojunction is constructed through the direct sulfurization of a metal ions exchanged Zn/Cd-MOF precursor(MOF=metal-organic framework material).The composition,structure,morphology,photoabsorption and photoelectric performance of the ZnS/CdS are characterized by powder X-ray diffraction(PXRD),scanning electron microscope(SEM),transmission electron microscope(TEM),diffuse reflection spectrum(DRS),photoelectric current(PEC),electrochemical impedance spectroscopy(El S)and photoluminescence(PL)*** the metal ions are highly orderly separated by the organic ligands and the inherent porosity of the Zn/Cd-MOF,the as-synthesized ZnS/CdS possesses a large surface area and intimate contact at the heterogeneous interface with uniform ZnS/CdS *** photocatalytic hydrogen evolution activity of the ZnS/CdS is investigated under visible light irradiation(A^420 nm).It exhibits enhanced photocatalytic performance that the optimal ZnS/CdS achieves a maximum average hydrogen production rate of 2348μmol·h^-1 g^-1.A possible electron transfer mechanism is therefore proposed by the analyses of the Mott-Schottky plots.

关键词： ZnS/CdS heterojunction Zn/Cd-MOF precursor Photocatalytic hydrogen evolution

Calcium ion pinned vanadium oxide cathode for high-capacity and long-life aqueous rechargeable zinc-ion batteries

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Science China Chemistry 2020年第12期63卷 1767-1776页

作者： Min Du Feng Zhang Xiaofei Zhang Wentao Dong Yuanhua Sang Jianjun wang Hong Liu shuhua wang State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China Institute for Advanced Interdisciplinary Research(iAIR) University of JinanJinan 250022China

Rechargeable aqueous zinc ion batteries (ZIBs),with the easy operation,cost effectiveness,and high safety,are emerging candidates for high-energy wearable/portable energy storage ***,the unsatisfactory energy density and undesired long-term cycling performance of the cathode hinder the development of ***,we report the chemical preintercalation of a small amount of calcium ions into V2O5 as the cathode *** cathode of Ca0.04V2O5·1.74H2O (CVO)was demonstrated to have a high specific capacity of 400 mA h g^-1at the current density of 0.05 A g^-1and 187 mA h g^-1at 10 A g^-1,along with impressive capacity retention (100%capacity retention at 10 A g^-1 for 3,000 cycles).Meanwhile,the CVO//Zn battery exhibits a high energy density of 308 Wh kg^-1and a power density of 467 W kg^-1at 0.5 A g^-*** superior performance originates from the pinning effect of the calcium ions and the lubricating effect of the structural *** energy storage mechanism of the CVO cathode was also investigated in *** new phase (Zn3(OH)2V2O7·2H2O) generated upon cycling participates in the electrochemical reaction and thus contributes to the excellent electrochemical *** small amount of Ca^2+ pre-inserted into the interlayer of V2O5 sheds light on constructing cathodes with high energy density for ZIBs.

关键词： aqueous zinc-ion battery ion pre-intercalation vanadium pentoxide phase transition energy storage mechanism

Fabrication of Mesoporous SiO_(2)@CaSiO_(3) Hollow Spheres as Carriers for pH-sensitive Drug Delivery

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Chemical Research in Chinese Universities 2022年第4期38卷 999-1004页

作者： YUAN Mingwei SHI Shunli LUO Yanping YU Ying wang shuhua CHEN Chao Key Laboratory of Jiangxi Province for Environment and Energy Catalysis College of ChemistryNanchang UniversityNanchang330031P.R.China

Hollow mesoporous silica(HM-SiO_(2))was prepared by the improved stober *** this basis,HM-SiO_(2) was dispersed in an alkaline solution for surface ***,calcium source was introduced to combine with SiO_(3)^(2−) on the surface to form a CaSiO_(3) shell layer and an unprecedent SiO_(2)@CaSiO_(3) sphere with a hollow double-shell structure was *** as-synthesized SiO_(2)@CaSiO_(3) was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),N_(2)-BET,IR and UV-Vis techniques,and its sustained release capacity of doxorubicin(DOX)loading was *** drug loading capacity can be achieved to 0.692 mg DOX/mg SiO_(2)@CaSiO_(3),exhibiting pH-responsivity under low pH conditions.

关键词： Hollow nano-sphere SiO_(2)@CaSiO_(3) Drug delivery pH-sensitive

Late Paleozoic-Early Mesozoic tectonic evolution of the Paleo-Asian Ocean： geochronological and geochemical evidence from granitoids in the northern margin of Alxa, Western China

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Frontiers of Earth Science 2018年第1期12卷 191-214页

作者： Xin SHA Jinrong wang Wanfeng CHEN Zheng LIU Xinwei ZHAI Jinlong MA shuhua wang School of Earth Sciences Gansu Key Laboratory of Mineral Resources in Western China Lanzhou University Lanzhou 730000 China State Key Laboratory for Mineral Deposits Research Nanjing University Nanjing 210000 China

The Paleo-Asian Ocean （Southern Mongolian Ocean） ophiolitic belts and massive granitoids are exposed in the Alxa block, in response to oceanic subduction processes. In this work, we report petrographic, geochem- ical, and zircon U-Pb age data of some granitoid intrusions from the northern Alxa. Zircon U-Pb dating for the quartz diorite, tonalite, monzogranite, and biotite granite yielded weighted mean 206pb/238U ages o f 302 ±9.2 Ma, 246.5±54.6 Ma, 235±4.4 Ma, and 229.5±5.6 Ma, respectively. The quartz diorites （-302 Ma） exhibit geochemical similarities to adakites, likely derived from partial melting of the initially subducted Chaganchulu back-arc oceanic slab. The tonalites （-246.5 Ma） display geochemical affinities of I-type granites. They were probably derived by fractional crystallization of the modified lithospheric mantle-derived basaltic magmas in a volcanic arc setting. The monzo- granites （-235 Ma） are characterized by low A1203, but high Y and Yb with notably negative Eu anomalies. In contrast, the biotite granites （-229.5 Ma） show high A1203 but low Y and Yb with steep HREE patterns and the absence of negative Eu anomalies. Elemental data suggested that the biotite granites were likely derived from a thickened lower crust, but the monzogranites originated from a thin crust. Our data suggested that the initial subduction of the Chaganchulu oceanic slab towards the Alxa block occurred at - 302 Ma. This subduction process continued to the Early Triassic （-246 Ma） and the basin was finally closed before the Middle Triassic （-235 Ma）. Subsequently, the break-off of the subducted slab triggered asthenosphere upwelling （240-230 Ma）.

关键词： Paleo-Asian Ocean ALxa granite geochemistry

Experimental Study of Motion of Nitrogen Taylor Bubbles and Liquid Slugs in Inclined Tubes

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Chinese Journal of Aeronautics 2009年第4期22卷 349-354页

作者： Zhang Hua,wang shuhua,wang Jing Institute of Engineering Thermo-physics,Shanghai Jiao Tong University,Shanghai 200240,China [a]Institute of Engineering Thermo-physics Shanghai Jiao Tong University Shanghai 200240 China

This article studies rising velocity of Taylor bubbles and liquid slugs in liquid nitrogen at different axial positions in upward inclined tubes by means of a high speed motion analyzer. The bottom-closed tubes in the experiments are 1.0 m long with an inner diameter of 0.014 m or 0.018 m. The tube inclines upward from 0~ to 50~ with respect to the normal. Statistical method is used to analyze the data of the Taylor bubble and the liquid slug velocity. Reflecting the effects of the inclination angle on the rising velocity of Taylor bubbles and liquid slugs, the experimental results indicate the similar trend the Taylor bubble velocity and the liquid slug velocity have： it increases first, and then decreases with the increase of the inclination angle. Moreover, with the increase of the inclination angle, the liquid slug velocity becomes greater than Taylor bubble velocity.

关键词： cryogenic two-phase flow rising velocity high speed motion analyzer liquid nitrogen Taylor bubble liquid slug inclined tube

NaOH/Urea Swelling Treatment and Hydrothermal Degradation of Waste Cotton Fiber

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Journal of Renewable Materials 2020年第6期8卷 703-713页

作者： Lixia Gao Sheng Shi Wensheng Hou shuhua wang Zhifeng Yan Chao Ge College of Textile Engineering Taiyuan University of TechnologyJinzhong030600China Jihua 3542 Textile Company Limited Xiangyang441000China

In this study,waste cotton fabric was used as cellulose raw material and pretreated in aqueous NaOH/urea solution system to investigate the effect of NaOH/urea pretreatment solution on the hydrolysis of cotton *** cotton fiber was pretreated with different conditions of aqueous NaOH/urea solution,and the pretreated cotton fiber was hydrolyzed under the same conditions as the original cotton *** results of characterization analysis showed that water retention value of pretreated cotton fiber was higher than that of unpretreated ***,the cotton fiber presented both a convoluted structure and a coarser surface,XRD results suggested that the crystallinity degree of cellulose decreased dramatically,more cellulose II appeared,and the hydrogen bond is *** the different pretreatment conditions,the pretreatment effect was the best when the reaction temperature was 0°C,the solid-liquid ratio was 2:50,and the NaOH/urea ratio was 7:*** hydrolysis experiments of pretreated and unpretreated cotton fibers showed that when the hydrothermal temperature was 230°C,the heat preservation was 2 h,and the hydrochloric acid concentration was 5 wt.%,the glucose yield reached 29.99%.H+could catalyze the hydrolysis of cotton fiber more effectively due to damage to crystal structure and hydrogen bonds.

关键词： Waste cotton fibers NaOH/urea pretreatment hydrolyze recycling and reusing

Highly Uniform Alkali Doped Cobalt Oxide Derived from Anionic Metal-Organic Framework:Improving Activity and Water Tolerance for CO Oxidation

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Chemical Research in Chinese Universities 2020年第5期36卷 946-954页

作者： LEI Huijin ZHANG Xinlu JIN Jiongke wang shuhua DING Shunmin ZHANG Ning CHEN Chao Key Laboratory of Jiangxi Province for Environment and Energy Catalysis College of ChemistryNanchang 330031P.R.China

A sequence of alkali metal cation-exchanged Co metal-organic frameworks(Co-MOFs),therein after denoted as M@Co-MOF,M=Na+,K+,Rb\and Cs+,was prepared and used as the precursors to obtain the corresponding alkali doped cobalt oxide(defined as M/C03O4,M=Na+,K\Rb\and Cs+)through calcination under air *** cobalt oxide modified by unifbnn alkali metals exhibited a significant promotion of catalytic activity for CO *** activity of M/Co3O4 decreased in the order of Cs+>Na+>K+>Rb+.Experimental and theoretical results revealed that the anionic skeleton of Co-MOF could tacilely adsorb alkali metal cations and play a cnicial role in the formation of higlily unilonn alkali doped cobalt *** further characterizations,such as temperature-programmed reduction of H2(H2-TPR),oxygen temperature-programmed desorption(O2-TPD),X-ray photoelectron spectroscopy(XPS),and in situ diffuse reflectance infrared Fourier transiorm(DRIFT)spectra demonstrated that the enlianced catalytic activity is originated from the interfacial electron transfer as well as weakened the Co-O bond strength,which promoted oxygen desorption from CO3O4 and fomiation of cobalt species with the lower valence *** Cs/Co3O4 catalyst was maintained for 60 h without deactivation and still showed a high activity in the presence of water.

关键词： Anionic framework Alkali metal CO oxidation M/Co3O4 Metal-organic framework precursor