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Geochemistry of Sediments from a Subalpine Lake Sedimentary Succession in the Western Nanling Mountains,Southern China:Implications for Catchment Weathering During the Last 15400 Years

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Chinese Geographical Science 2022年第3期32卷 537-548页

作者： WANG Bingxiang ZHONG wei ZHU Chan OUYANG Jun wei Zhiqiang shang Shengtan School of Geography Sciences South China Normal UniversityGuangzhou 510631China Guangdong Center for Marine Development Research Guangzhou 510220China Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityZhuhaiGuangdong 519087China School of Earth Science and Engineering Sun Yat-sen UniversityZhuhai 519082China

In the present work,15400 yr old geochemical records of a core from the subalpine Daping swamp are presented with the aim to examine the relationship between the chemical weathering and the climatic changes in the region of the western Nanling Mountains,*** climate of the study region was deeply controlled by the East Asian summer *** results indicate that,in the past 15400 yrs,the values of chemical index of alteration(CIA)ranged from 73.9%to 88.2%(mean:85.3%),suggested a medium and high intensity of chemical *** local exogenous clastic materials,which were derived from the weathered residues,played a key role in contributing towards the *** the climate-induced chemical weathering exerted strong influences on the geochemical features of weathered residues,the geochemical characteristics of the sediments were deeply impacted by climatic *** and warmer conditions would favor increased chemical weathering,resulting in more leaching of soluble and mobile elements(e.g.,Ba and Sr)and leaving the resistant and immobile elements(e.g.,Al and Ti)enriched in the weathered *** materials were then eroded and transported into the lake,and led to the sediments characterized by the characteristic of having depleted soluble *** contrast,dry and cold conditions would result in an opposite *** this sense,the geochemical records can serve as proxies to indicate changes of chemical weathering intensity,which were closely related to the evolution of summer monsoon.

关键词： lacustrine sediments chemical weathering asian summer monsoon last deglacial western Nanling Mountains China

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Stellar structure of magnetars

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Science China(Physics,Mechanics & Astronomy) 2016年第4期59卷 66-70页

作者： JianMin Dong wei Zuo JianZhong Gu XinLe shang Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China China Institute of Atomic Energy Beijing 102413 China

Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated magnetars. The stellar structure together with the magnetic field configuration can be obtained at the same time within a self-consistent procedure. The magnetar mass and radius are found to be weakly enhanced by the strong magnetic fields. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.

关键词： neutron stars magnetic and electric fields equations of state of neutron-star matter

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Improving hydrogen storage thermodynamics and kinetics of Ce-Mg-Ni-based alloy by mechanical milling with TiF_(3)

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Journal of Magnesium and Alloys 2024年第4期12卷 1593-1607页

作者： Hongwei shang wei Zhang Xin wei Yaqin Li Zeming Yuan Jun Li Yanghuan Zhang School of Mechanical and Electrical Engineering Chuzhou UniversityChuzhou 239000China Department of Functional Material Research Central Iron and Steel Research InstituteNo.76 Xueyuannan RoadHaidian DistrictBeijing 100081China Key Laboratory of Integrated Exploitation of Bayan-Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010China China Rare Earth New Material(weishan)Co. Ltd.Jining 277600China

Mg-based hydrides are too stable and the kinetics of hydrogen absorption and desorption is not *** efficient way to improve these shortcomings is to employ reactive ball milling to synthesize the nanocomposite materials of Mg and *** this experiment,TiF_(3)was selected as an additive,and the mechanical milling method was employed to prepare the experimental *** alloys used in this experiment were the as-cast Ce_(5)Mg_(85)Ni_(10),as-milled Ce_(5)Mg_(85)Ni_(10)and Ce_(5)Mg_(85)Ni_(10)+3 wt.%*** phase transformation,structural evolution,isothermal and non-isothermal hydrogenation and dehydrogenation performances of the alloys were inspected by XRD,SEM,TEM,Sievert apparatus,DSC and *** revealed that nanocrystalline appeared in the as-milled *** with the as-cast alloy,ball milling made the particle dimension and grain size decrease dramatically and the defect density increase *** addition of TiF_(3)made the surface of ball milling alloy particles markedly coarser and more *** milling and adding TiF_(3)distinctly improved the activation and kinetics of the ***,ball milling along with TiF_(3)can decrease the onset dehydrogenation temperature of Mg-based hydrides and slightly ameliorate their thermodynamics.

关键词： Mg-based hydrides TiF_(3) Ball milling Thermodynamics Kinetics

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Grain refinement in the coarse-grained region of the heat-affected zone in low-carbon high-strength microalloyed steels

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 737-741页

作者： Ran wei Cheng-jia shang Kai-ming Wu International Research Institute for Steel Technology Wuhan University of Science and Technology Wuhan 430081 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The microstructural features and grain refinement in the coarse-grained region of the heat-affected zone in low-carbon high-strength microalloyed steels were investigated using optical microscopy, scanning electron microscopy, and electron backscattering dif- fraction. The coarse-grained region of the heat-affected zone consists of predominantly bainite and a small proportion of acicular ferrite. Bainite packets are separated by high angle boundaries. Acicular ferrite laths or plates in the coarse-grained region of the heat-affected zone formed prior to bainite packets partition austenite grains into many smaller and separate areas, resulting in fine-grained mixed microstruc- tures. Electron backscattefing diffraction analysis indicates that the average crystallographic grain size of the coarse-grained region of the heat-affected zone reaches 6-9 μm, much smaller than that of anstanite grains.

关键词： microalloyed steels welding grain refinement bainite acicular ferrite

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A conductive and biodegradable hydrogel for minimally delivering adipose-derived stem cells

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Science China(Technological Sciences) 2019年第10期62卷 1747-1754页

作者： shang YingYing LIANG wei TAN BaoYu XIAO Meng ZOU Yang LIU WenGuang WANG wei Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and Engineering Tianjin University

Injectable hydrogel is one of the most important biomaterials for tissue engineering and drug delivery. However, it is still a challenge to obtain an injectable hydrogel with conductive property on account of the poor water solubility of conductive polymers. Here, a conductive hydrogel with controllable biodegradability was constructed for minimally delivering adipose mesenchymal stem cells(ADSCs). Firstly, a disulfide containing and hyperbranched polymer structure poly(β-amino ester)(PBAE) with multi-acrylate end groups was synthesized by poly(ethylene glycol) diacrylate(PEGDA) and cystamine, and then tetraaniline(TA) was grafted on the PBAE chain to obtain a conductive PBAE-TA polymer. PBAE-TA shows a good water solubility, which can be crosslinked by thiol-modified hyaluronic acid(HA-SH) due to the click reaction between acrylate and thiol to in situ form a hydrogel within 1 min. The hydrogel illustrates a good electrical conductivity of 9.6×10–3 S/cm and a controllable biodegradable behavior in dithiothreotol(DTT) solution. PBAE-TA/HA-SH hydrogel was subcutaneously injected for delivering ADSCs. The gene expression of Cx43 and TGF-β1 were up-regulated by PBAE-TA/HA-SH hydrogel, suggesting an enhancement in the electrical coupling and an anti-inflammatory property. This injectable, biodegradable, and conductive hydrogel can effectively deliver stem cells, which might be used in skin, muscle, and myocardium regeneration.

关键词： injectable hydrogel conductivity biodegradability ADSCs

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A smoothed assumed enhanced strain method for frictional contact with constant strain elements

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4369-4385页

作者： Fushen Liu wei Sun Minghui Li Xiaonan shang Computing Center for Geotechnical Engineering Zhejiang UniversityHangzhou310058China Research Center of Coastal and Urban Geotechnical Engineering Zhejiang UniversityHangzhou310058China Engineering Research Center of Urban Underground Development of Zhejiang Province Hangzhou310058China School of Civil Engineering Sun Yat-sen UniversityGuangzhou510275China School of Energy Resource China University of Geosciences(Beijing)Beijing100083China

This paper presents a finite element framework for imposing frictional contact conditions on embedded fracture faces,implemented by the constant-strain assumed enhanced strain(AES)method,where penalty method is used to impose both non-penetration constraint and Coulomb’s law of *** proposed constant-strain AES method for modeling embedded frictional contact can be cast into an integration algorithm similar to those used in the classical plasticity theory,where displacement jump is calculated from the local traction equilibrium at Gauss point,so the method does not introduce any additional global degrees of ***,constant-strain elements are often desirable in practice because they can be easily created automatically for large-scale engineering applications with complicated *** encountered in other enriched finite element methods for frictional contact,the problem of normal contact pressure oscillations is also observed in the constant-strain AES ***,we developed a strain-smoothing procedure to effectively mitigate the *** investigated and verified the proposed AES framework through several numerical examples,and illustrated the capability of this method in solving challenging nonlinear frictional contact problems.

关键词： Assumed enhanced strain(AES)method Frictional contact Strain-smoothing method Penalty method

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Highly Stable CsPbBr_(3) Nanocrystal Phosphors by Surface Passivation and Encapsulation

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Chemical Research in Chinese Universities 2022年第2期38卷 588-595页

作者： shang Zheliang XUE weinan WANG wei LI Yan shanghai Key Laboratory of Functional Materials Chemistry Institute of Applied ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237P.R.China

The colloidal all-inorganic CsPbX_(3)(X=I, Br, Cl) perovskite nanocrystals(NCs) with unique optical properties have attracted considerable attention in the field of semiconductor nanocrystals, but their application is hindered by stability issues caused by surface defects and environmental factors. Usually with inert layer encapsulation, the stability of CsPbX_(3) NCs can be significantly enhanced. However, due to the loss of highly dynamic oleic acid/oleylamine ligands, it is usually accompanied by a decrease in the photoluminescence quantum yield(PLQY). Herein, we report a facile method for preparing CsPbBr_(3) NCs based green phosphors with high stability and bright emission. With modification of colloidal CsPbBr_(3) NCs by di-dodecyldimethylammonium bromide and sequent encapsulation in the as-synthesized mesoporous MOF-5, the green emitting phosphors with enhanced stability and a PLQY of 77% were obtained. The phosphors exhibit enhanced resistance against ambient oxygen, UV light, heat treatment and water. These excellent properties show the potential value of our prepared NCs as stable phosphors in light-emitting devices.

关键词： Perovskite nanocrystal Phosphor Surface passivation Encapsulation Mesoporous MOF-5

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Robust sliding mode control with ESO for dual-control missile

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Journal of Systems Engineering and Electronics 2016年第5期27卷 1073-1082页

作者： wei shang shengjing tang jie guo yueyue ma yuhang yun School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China

This paper proposes a novel composite dual-control bycombing the integral sliding mode control （ISMC） method basedon the finite time convergence theory with extended state observer（ESO） for a tracking problem of a missile with tail fins and reactionjetcontrol system （RCS）. First, the ISMC method based on finitetime convergence is utilized to design the control law of tail fins andthe pulse control of RCS for the dual-control system, ensuring thesystem with rapid response and high accuracy of tracking. Then,ESO is employed for the estimation of aerodynamic disturbancesinfluenced by the airflow of thruster jets. With the characteristicof high accuracy estimation of ESO, the chattering free trackingperformance of the attack angle command and the robustnessof the control law are achieved. Meanwhile, the stability of thedual-control system is analyzed based on finite time convergencestability theorem and Lyapunov’s theorem. Finally, numerical simulationsdemonstrate the effectiveness of the proposed design.

关键词： reaction-jet control system (RCS) tail fins system,integral sliding mode control extended state observer (ESO).

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Analysis model for damage of reinforced bars in RC beams under contact explosion

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Defence Technology（防务技术） 2024年第11期41卷 104-118页

作者： Chaozhi Yang Zhengxiang Huang Xin Jia wei shang Jian Zhang The 716th Research Institute China State Shipbuilding Corporation LimitedLianyungang222006China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China Hua'an Industry Group Ltd Qiqihar161006China

The load-bearing capacity of reinforced concrete(RC) beams primarily relies on internal reinforced ***, limited research has been conducted on the dynamic response of these bars. To address this gap, this study has established an analytical model using dimensional analysis for calculating the deformation of reinforced bars within RC beams subjected to contact explosion. Comparison with experimental data reveals that the model has a relative error of 5.22%, effectively reflecting the deformation of reinforced bars. Additionally, based on this model, the study found that while concrete does influence the deformation of reinforced bars, this influence can be disregarded in comparison to the material properties of the bars themselves. The findings of this study have implications for calculating the residual load-bearing capacity of damaged RC beams, evaluating the extent of damage to RC beams after blast loading, and providing guidance for the blast-resistant design of RC structures.

关键词： Reinforced concrete beam Contact explosion Reinforced bar Damage analysis Residual load-bearing capacity

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Tracking controller design for air handling units with uncertainties

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Building Simulation 2023年第4期16卷 547-556页

作者： Fang shang Yongshuai Ji wei Peng Jingdong Duan Yikai Yin Shandong Key Laboratory of Intelligent Buildings Technology School of Information and Electrical EngineeringShandong Jianzhu UniversityJinan 250101China QingDao iESLab Electronic Co. LTD.Jinan 250101China

As an important component of the heating,ventilating and air conditioning(HVAC)systems,air handling units(AHUs)are responsible for regulating indoor temperature and *** this paper,a multivariable nonlinear dynamic model of the AHUs with unknown strength of the humidity source is considered,and an improved backstepping controller is proposed to realize the tracking objective of the indoor temperature,relative humidity and carbon dioxide ***,the original system is represented in simplified state space form,and then the state transformation is introduced with a gain to overcome the difficulty caused by the unknown strength of the humidity ***,the improved backstepping controller is designed in a step-by-step ***,the stability of the closed-loop system is analyzed in ***,we consider the case that the AHUs work in summer of Jinan,China,as an *** simulation results show the effectiveness of the ***,the performance of the improved backstepping controller are compared with that of the decoupled sliding mode and PID controllers.

关键词： air handling units tracking control uncertain parameters backstepping

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