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Mechanism of Mg2+ dissolution from olivine and serpentine: Implication for bioleaching of high-magnesium nickel sulfide ore at elevated pH

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International Journal of Minerals,Metallurgy and Materials 2019年第9期26卷 1069-1079页

作者： jian-zhi Sun jian-kang wen Bo-wei Chen Biao Wu National Engineering Laboratory of Biohydrometallurgy GRINM Group Corporation Limited

To inhibit the dissolution of Mg^2+ during the bioleaching process of high-magnesium nickel sulfide ore, the effect of major bioleaching factors on the dissolution of Mg^2+ from olivine and serpentine was investigated and kinetics studies were carried out. The results indicated that the dissolution rate-controlling steps are chemical reaction for olivine and internal diffusion for serpentine. The most influential factor on the dissolution of Mg^2+ from olivine and serpentine was temperature, followed by p H and particle size. A novel method of bioleaching at elevated pH was used in the bioleaching of Jinchuan ore. The results showed that elevated pH could significantly reduce the dissolution of Mg^2+ and acid consumption along with slightly influencing the leaching efficiencies of nickel and cobalt. A model was used to explain the leaching behaviors of high-magnesium nickel sulfide ore in different bioleaching systems. The model suggested that olivine will be depleted eventually, whereas serpentine will remain because of the difference in the rate-controlling steps. Bioleaching at elevated pH is a suitable method for treating high-magnesium nickel sulfide ores.

关键词： olivine serpentine high-magnesium nickel sulfide ore bioleaching shrinking core model elevated pH

Modeling of coal consumption rate based on wavelet neural network

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International Journal of Modeling, Simulation, and Scientific Computing 2017年第3期8卷 78-92页

作者： Xiaoqiang wen Shuguang jian Department of Automation Northeast Electric Power University Jilin P.R.China

In this paper,two wavelet neural network(WNN)frames which depend on Morlet wavelet function and Gaussian wavelet function were *** order to improve the efficiency of model training,the momentum term was applied to modify the weights and thresholds,and the output of the network was summed up by function transformation of output layer *** the Gaussian Wavelet Neural Networks(GWNN)and Morlet Wavelet Neural Networks(MWNN)were applied to coal consumption rate(CCR)estimation in a thermal power plant,the results confirmed their potency in function *** addition,the influence of learning rate on the models was also discussed through the orthogonal experiment.

关键词： Wavelet neural network Morlet wavelet function Gaussian wavelet function estimation coal consumption rate

Optimal Technology Investment under Emission Trading Policy

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Journal of Systems Science and Systems Engineering 2020年第2期29卷 143-162页

作者： Shuo Huang Zhong wen jian Chen Ning Cui School of Economics and Management Tsinghua UniversityBeijing 100084China Beijing Foreign Studies University China Southern Asset Management Co. Ltd.

Low-carbon economy is gaining growing attention nowadays as global warming *** a market-based policy,emission trading policy is widely considered an effective means to achieve the doublewin of economic development and environmental *** such circumstances,carbon trading markets are developing rapidly in many countries and regions,demanding more attention to compliance strategy issues for emission-intensive *** this study,we build a dynamic programming model in search of the optimal emission trading and technology investment decisions for a make-to-order company faced with a stochastic demand under emission trading *** a comprehensive analysis of the proposed model,we find that an optimal emission permit level,which increases in carbon penalty and decreases in carbon price,exists in each *** for the abatement technology investment decision,the firm should invest only ff the investment cost per unit of abatement effort is less than a certain threshold,which increases in carbon penalty and carbon *** the basis of a two-period dynamic programming model,we further explore the problem of investment *** show how optimal investment decisions are influenced by the speed of technology progress under different *** findings are important for firms to choose the time of investment depending on specific situations.

关键词： Low-carbon emission trading compliance strategy investment-timing

Preparations of TiO_2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

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Journal of Environmental Sciences 2007年第1期19卷 80-85页

作者： HU Hai XIAO wen-jun YUAN jian SHI jian-wei CHEN Ming-xia SHANG GUAN wen-feng Research Center for Combustion and Environment Technology Shanghai Jiao Tong University. Shanghai 200030 China

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.

关键词： photocatalyst TiO2 films foam nickel sol-gel acetaldehyde degradation

Effect of flash processing on recrystallization behavior and mechanical performance of cold-rolled IF steel

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1234-1243页

作者： Peng-yu wen jian-sheng Han Hai-wen Luo Xin-ping Mao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Department of Ferrous Metallurgy University of Science and Technology BeijingBeijing 100083China

Flash processing(FP)has attracted considerable attention due to its high efficiency,economic advantages,and the extraordinary opportunity if offers to improve the mechanical properties of *** this study,we investigated the influences of FP on the recrystallization(REX)behavior and mechanical performance of cold-rolled IF *** a thermomechanical simulator,we performed both single-stage FPs,at heating rates of 200℃/s and 500℃/s,and two-stage FP,with an initial preheating to 400℃ at a rate of 5℃/s and then to peak temperatures at a rate of 200℃/*** comparison to continuous annealing(CA),single-stage FP can effectively refine the recrystallized grain sizes and produce a similar or even sharperγ(ND(normal direction)//{111})texture *** particular,the heating rate of 500℃/s led to an increase in the yield strength of about 23.2%and a similar *** contrast,the two-stage FP resulted in a higher REX temperature as well as a certain grain refinement due to the stored strain energy,i.e.,the driving force of REX,which was largely consumed during ***,both stronger{110}and weakerγtexture components appeared in the two-stage FP and were believed to be responsible for the early necking and deterioration in ductility.

关键词： flash processing interstitial-free steel recrystallization mechanical properties texture

A novel approach to extract Nb,Y and Ce from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4) system

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Rare Metals 2021年第7期40卷 1979-1986页

作者： wen-Cheng Gao jian-Kang wen Biao Wu He Shang Xue Liu National Engineering Laboratory of Biohydrometallurgy GRIMAT Engineering Institute Co.LtdBeijing 101407China GRINM Resources and Environment Tech.Co. LtdBeijing 101407China

In this work,a novel approach of leaching valuable metals,such as niobium,yttrium and cerium,from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4)system was experimentally *** the work,the effects of roasting temperature,roasting time,mass ratio of agents to ore and the types of leaching agents on the extraction of Nb,Y and Ce were investigated,and the roasting KHSO_(4)-H_(2)SO_(4)-ore system was thought as an effective method to extract these valuable *** was found that the recovery of Nb,Y and Ce can,respectively,reach 90.20%,97.22%and 98.41%in condition of roasting temperature of 300℃,roasting time of 2 h,mass ratio of KHSO_(4)-to-H_(2)SO_(4)to ore of 0.5:1:1,particle size of-74 lm(~95%),leaching solution of oxalic acid(30 g·L^(-1)),leaching temperature of 90℃and leaching liquid-to-solid ratio of 5:*** leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model,and the apparent activity energy was obtained to be14.16 kJ·mol^(-1).The results generated from this work will provide the fundamentals for extracting Nb,Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.

关键词： Roasting Extraction Niobium Yttrium Cerium Low grade

阿仑膦酸钠/壳聚糖/聚乙烯醇复合水凝胶膜的制备与表征

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中国组织工程研究 2025年第22期29卷 4720-4730页

作者：胡晨姜莹陈佳乔光伟董文马坚宁夏医科大学总医院口腔颌面外科宁夏回族自治区银川市750004 徐州市口腔医院口腔颌面外科江苏省徐州市221000 宁夏医科大学总医院口腔医院正畸科宁夏回族自治区银川市750004

背景:骨质疏松症是牙种植治疗的高风险因素,制备缓释阿仑膦酸钠的组织工程支架应用于骨质疏松患者口腔种植手术是当前口腔骨组织工程研究热点。目的:制备阿仑膦酸钠/壳聚糖/聚乙烯醇复合水凝胶膜,表征其缓释性能。方法:(1)采用物理交联... 详细信息

背景:骨质疏松症是牙种植治疗的高风险因素,制备缓释阿仑膦酸钠的组织工程支架应用于骨质疏松患者口腔种植手术是当前口腔骨组织工程研究热点。目的:制备阿仑膦酸钠/壳聚糖/聚乙烯醇复合水凝胶膜,表征其缓释性能。方法:(1)采用物理交联法制备不同质量比(壳聚糖与聚乙烯醇的质量比分别为3∶7、5∶5、7∶3)的壳聚糖/聚乙烯醇复合水凝胶膜与单纯的壳聚糖、聚乙烯醇水凝胶膜,通过表征水凝胶膜的形貌、水接触角、力学性能、溶胀率与细胞相容性筛选适宜的水凝胶膜作为阿仑膦酸钠的载体。(2)制备含0,0.4,1.2,2.0 mg/L阿仑膦酸钠的单纯壳聚糖/聚乙烯醇复合水凝胶膜,将大鼠骨髓间充质干细胞分别与4组水凝胶膜共培养,通过CCK-8法与CD44免疫荧光染色检测水凝胶膜的细胞相容性。将载药壳聚糖/聚乙烯醇复合水凝胶膜浸泡于PBS中,采用紫外可见分光光度法检测复合水凝胶膜的药物释放性能。结果与结论:(1)表征结果显示,随着水凝胶膜中聚乙烯醇质量的增加,水凝胶膜的结构密度增加、孔隙率减少,水接触角(均在90°以内)、断裂伸长率与抗压强度增大,平衡溶胀率降低,对大鼠骨髓间充质干细胞的增殖均无影响,单纯壳聚糖水凝胶膜可促进大鼠骨髓间充质干细胞的黏附,3∶7、5∶5比例复合水凝胶膜不影响大鼠骨髓间充质干细胞的黏附,单纯聚乙烯醇水凝胶膜、7∶3比例复合水凝胶膜抑制大鼠骨髓间充质干细胞的黏附,综合以上结果,选择5∶5复合水凝胶膜作为阿仑膦酸钠的载体。(2)CCK-8检测结果显示,含0.4,1.2 mg/L阿仑膦酸钠组复合水凝胶膜无细胞毒性;CD44免疫荧光染色结果显示,含0.4 mg/L阿仑膦酸钠组复合水凝胶膜不影响大鼠骨髓间充质干细胞的黏附,含1.2,2.0 mg/L阿仑膦酸钠组复合水凝胶膜抑制大鼠骨髓间充质干细胞的黏附;含0.4,1.2,2.0 mg/L阿仑膦酸钠的壳聚糖/聚乙烯醇复合水凝胶膜在最初6 h内爆发性释放阿仑膦酸钠,此后均匀稳定地释放阿仑膦酸钠,释放时间达96 h以上。(3)结果表明,5∶5比例的壳聚糖/聚乙烯醇复合水凝胶膜具有良好的理化性能、细胞相容性,可以作为阿仑膦酸钠的缓释载体。

关键词：阿仑膦酸钠壳聚糖聚乙烯醇水凝胶复合水凝胶膜种植体

Generalized Polynomial Chaos for Nonlinear random Pantograph Equations

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Acta Mathematicae Applicatae Sinica 2016年第3期32卷 685-700页

作者： wen-jie SHI Cheng-jian ZHANG School of mathematics and statistics Huazhong University of Science and Technology School of Mathematics and Computer Science Wuhan Textile University

This paper is concerned with the application of generalized polynomial chaos （gPC） method to nonlinear random pantograph equations. An error estimation of gPC method is derived. The global error analysis is given for the error arising from finite-dimensional noise （FDN） assumption, projection error, aliasing error and discretization error. In the end, with several numerical experiments, the theoretical results are further illustrated.

关键词： generalized polynomial chaos random pantograph equations error estimation finite-dimensional noise

Generalized system for strongly g-r-pseudomonotonic nonlinear variational inequalities in Hilbert spaces

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Applied Mathematics(A Journal of Chinese Universities) 2010年第1期25卷 63-68页

作者： YANG Xin-bo PENG jian-wen Department of Computer Science Chongqing Education College Chongqing 400067 China College of Mathematics and Computer Science Chongqing Normal University Chongqing 400047China

The approximation solvability of a generalized system for strongly g-r- pseudomonotonic nonlinear variational inequalities in Hilbert spaces is studied based on the convergence of the projection method. The results pr... 详细信息

关键词： Projection method strong g-r-pseudomonotonicity variational inequality convergence.