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Topsoil organic carbon mineralization and CO_2 evolution of three paddy soils from South China and the temperature dependence

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Journal of Environmental Sciences 2007年第3期19卷 319-326页

作者： ZHANG Xu-hui LI Lian-qing pan Gen-xing Institute of Resources Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China.

Carbon mineralization and its response to climatic warming have been receiving global attention for the last decade. Although the virtual influence of temperature effect is still in great debate, little is known on the mineralization of organic carbon （SOC） of paddy soils of China under warming. SOC mineralization of three major types of China＇s paddy soils is studied through laboratory incubation for 114 d under soil moisture regime of 70% water holding capacity at 20℃ and 25℃ respectively. The carbon that mineralized as CO2 evolved was measured every day in the first 32 d and every two days in the following days. Carbon mineralized during the 114 d incubation ranged from 3.51 to 9.22 mg CO2-C/gC at 20℃ and from 4.24 to 11.35 mg CO2-C/gC at 25℃ respectively; and a mineralizable C pool in the range of 0.24 to 0.59 gC/kg, varying with different soils. The whole course of C mineralization in the 114 d incubation could be divided into three stages of varying rates, representing the three subpools of the total mineralizable C： very actively mineralized C at 1-23 d, actively tnineralized C at 24--74 d and a slowly mineralized pool with low and more or less stabilized C mineralization rate at 75-114 d. The calculated Q10 values ranged from 1.0 to 2.4, varying with the soil types and N status. Neither the total SOC pool nor the labile C pool could account for the total mineralization potential of the soils studied, despite a well correlation of labile C with the shortly and actively mineralized C, which were shown in sensitive response to soil warming. However, the portion of microbial C pool and the soil C/N ratio controlled the C mineralization and the temperature dependence. Therefore, C sequestration may not result in an increase of C mineralization proportionally. The relative control of C bioavailability and microbial metabolic activity on C mineralization with respect to stabilization of sequestered C in the paddy soils of China is to be further studied.

关键词： C mineralization carbon pool laboratory incubation paddy soil soil warming

Effects of surface nanostructure on boundary lubrication using molecular dynamics

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Nanotechnology and Precision Engineering 2021年第3期4卷 54-62页

作者： Ling pan hui Yu Shiping Lu Guobin Lin School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China

Molecular dynamics simulations are used to study the boundary lubrication behaviors of squalane lubricant between two iron wall structures during shearing at different pressures and *** lubrication models with a smooth iron wall and a nanostructured iron wall,respectively,are constructed,and the density distribution of the lubricating film and the velocity distribution in the shearing process are *** mechanical response of the solid wall is output,and the friction coefficient is calculated.A tribological test is performed with a UMT-2 tribometer under sliding conditions to evaluate the reliability of the simulation *** results show that the surface nanostructure has a significant effect on the film thickness and delamination of the lubricating film but little effect on the velocity distribution of the lubricating *** nano strip groove helps to reduce the friction coefficient of the boundary lubrication system.

关键词： Boundary lubrication Rough surface Molecular dynamics Lubricating film Friction coefficient

Structure and Dynamics of Energy Materials from Machine Learning Simulations:A Topical Review

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Chinese Journal of Chemistry 2021年第11期39卷 3144-3154页

作者： Shu-hui Guan Cheng Shang Zhi-pan Liu Shanghai Academy of Agricultural Sciences Shanghai201403 China Collaborative Innovation Center of Chemistry for Energy Material Shanghai Key Laboratory of molecular Catalysis and Innovative MaterialsKey Laboratory of Computational Physical ScienceDepartment of ChemistryFudan UniversityShanghai200438 China

Energy materials featuring the capability to store and release chemical energy reversibly involve generally complex geometrical structures with multiple *** has been a great challenge to establish the quantitative relationship between the structure of materials and their dynamic physicochemical *** recent years,machine learning(ML)technique has demonstrated its great power in accelerating the research on energy *** topical review introduces the key ingredients and typical applications of ML to energy *** mainly focus on the ML based atomic simulation via ML potentials in different architectures/implementations,including high dimensional neural networks(HDNN),Gaussian approximation potential(GAP),moment tensor potentials(MTP)and stochastic surface walking global optimization with global neural network potential(SSW-NN)*** cases studies,namely,Si,LiC and LiTiO systems,are presented to demonstrate the ability of ML simulation in assessing the thermodynamics and kinetics of complex material *** highlight that the SSW-NN method provides an automated solution for global potential energy surface data collection,ML potential construction and ML simulation,which boosts the current ability for large-scale atomic simulation and thus holds the great promise for fast property evaluation and material discovery.

关键词： Machine learning Materials science Atomic simulation Thermodynamics Kinetics

Mineral structure and crystal morphologies of high-iron hydrargillite

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International Journal of Minerals,Metallurgy and Materials 2018年第5期25卷 505-514页

作者： hui-bin Yang Feng-qin Liu xiao-lin pan Hangzhou Yinsheng Enterprise Management Co. Ltd. School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Metallurgy Northeastern University

Various characterization methods, including scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller surface-area measurements, thermogravimetry–differential scanning calorimetry, X-ray diffraction, and infrared spectroscopy, were used to study the mineral structure and surface characteristics of high-iron hydrargillite. Gibbsite, goethite, and hematite were found to be the main mineral components of hydrargillite, whereas the goethite and hematite were closely clad to the surface of the multilayer gibbsite crystals. Compared with the synthetic gibbsite, the hydrargillite contained more structural micropores generated by the mineral evolution during the mineralization process. The gibbsite in hydrargillite contained less crystal water compared with the synthetic gibbsite, and it was a typical polymorphic structure. The isomorphous substitution of Al and Fe was observed in goethite. The dissolution-controlling step of hydrargillite was the ionic diffusion speed because of the goethite and hematite that closely covered and encapsulated the gibbsite crystals.

关键词： hydrargillite goethite gibbsite mineral structure crystal morphologies

Boron removal from metallurgical grade silicon by slag refining based on GA-BP neural network

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Rare Metals 2021年第1期40卷 237-242页

作者： Shi-Lai Yuan hui-Min Lu pan-pan Wang Chen-Guang Tian Zhi-Jiang Gao School of Materials Science and Engineering.Beijing University of Aeronautics and Astronautics Beijing 100191China

In order to investigate the boron removal effect in slag refining process,intermediate frequency furnace was used to purify boron in SiO2-CaO-Na3 AlF6-CaSiO3 slag system at 1,550℃,and back propagation(BP)neural network was used to model the relationship between slag compositions and boron content in SiO2-CaO-Na3 AlF6-CaSiO3 slag *** BP neural network predicted error is below 2.38%.The prediction results show that the slag composition has a significant influence on boron *** the basicity of slag by adding CaO or Na3 AlF6 to CaSiO3-based slag could contribute to the boron removal,and the addition of Na3 AlF6 has a better removal effect in comparison with the addition of *** oxidizing characteristic of CaSiO3 results in the ineffective removal with the addition of *** increase of oxygen potential(pO2)in the CaO-Na3 AlF6-CaSiO3 slag system by varying the SiO2 proportion can also contribute to the boron removal in silicon *** best slag composition to remove boron was predicted by BP neural network using genetic algorithm(GA).The predicted results show that the mass fraction of boron in silicon reduces from 14.0000×10-6 to0.4366×10-6 after slag melting using 23.12%SiO2-10.44%CaO-16.83%Na3 AlF6-49.61%CaSiO3 slag system,close to the experimental boron content in silicon which is below 0.5×10-6.

关键词： Metallurgical grade silicon Boron removal Slag system Genetic algorithm-back propagation neural network

A Review on Nano-/Microstructured Materials Constructed by Electrochemical Technologies for Supercapacitors

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Nano-Micro Letters 2020年第9期12卷 147-202页

作者： huizhen Lv Qing pan Yu Song xiao‑xia Liu Tianyu Liu Department of Chemistry Northeastern UniversityShenyang 110819People’s Republic of China Department of Chemistry Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA

The article reviews the recent progress of electrochemical techniques on synthesizing nano-/microstructures as supercapacitor *** a history of more than a century,electrochemical techniques have evolved from metal plating since their inception to versatile synthesis tools for electrochemically active materials of diverse morphologies,compositions,and *** review begins with tutorials on the operating mechanisms of five commonly used electrochemical techniques,including cyclic voltammetry,potentiostatic deposition,galvanostatic deposition,pulse deposition,and electrophoretic deposition,followed by thorough surveys of the nano-/microstructured materials synthesized ***,representative synthesis mechanisms and the state-of-the-art electrochemical performances of exfoliated graphene,conducting polymers,metal oxides,metal sulfides,and their composites are *** article concludes with summaries of the unique merits,potential challenges,and associated opportunities of electrochemical synthesis techniques for electrode materials in supercapacitors.

关键词： Nanostructure Microstructure Electrochemical Synthesis Supercapacitor

A Computational Investigation of the Group Effect of Pits on the Ultimate Strength of Steel Plates

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China Ocean Engineering 2018年第6期32卷 665-674页

作者： FU Qiang FANG hui WU Ren-xia YU Xue-hui LI Hua-jun Institute of Coastal and Offshore Engineering School of Engineering Ocean University of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Engineering Xi'an Jiaotong University

In this work, we focus on assessing the group effect of localized corrosion on the ultimate strength of the marine structural plates and study the load-deformation behaviors of plates of various slenderness and uniaxial ***, we investigate different corroded patterns from a single circular pit to 25 circular pits distributed over the plate and carry out hundreds of nonlinear finite element simulations by combining the number, depth, distribution of pits with imperfections and slenderness of plate. The distribution of multiple pits causes scattering of stress concentration on the plate, then the plastic section of plate changes with wider distribution of damage simultaneously. The ultimate strength arises when un-loading zone comprised of the yielding strips and holes extends across the plate. It can be concluded that the corroded condition defined as group effect of pits manipulates the deformation state and the loading capacity of plate at the ultimate strength mode that coincides with the proportion of effective loading area and section in the process of post-buckling. To validate the effect of pits group, we perform the numerical experiments of the post-buckling of steel plates containing pits in a row with different orientation.

关键词： group effect localized corrosion post-buckling ultimate strength

A theoretical model for impact protection of flexible polymer material

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 217-226页

作者： huifeng Xi hui pan Song Chen Heng xiao MOE Key Lab of Disaster Forecast and Control in Engineering School of Machanics and Construction EngineeringJinan UniversityGuangzhou 510632China Doctor Workstation of Xuwen County Guangdong Hydropower Energy Co. Ltd.Xuwen 524100China

The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is *** on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is *** feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by *** model is discretized and the relationship between local impact response andmaterial parameters is *** discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.

关键词： Flexible polymer material Viscoelastic material Kelvin modelDynamic response Elastic modulus and viscosity coefficient

Synthesis and Crystal Structure of a Novel Complex [Ag(NIT3Py)_3]·(ClO_4)(H_2O)

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Chinese Journal of Structural Chemistry 2005年第6期24卷 625-628页

作者： ZHANGChen-xia LIAODai-Zheng JIANGZong-hui YANShi-Ping SchoolofMaterialsScienceandEngineering TianjinUniversityTianjin300072China／／DepartmentofChemistryNankaiUniversityTianjin300071China DepartmentofChemistry NankaiUniversityTianjin300071China DepartmentofChemistry NankaiUniversityTianjin300071China／／StateKeyLaboratoryofCoordinationChemistryNanjing210093China

A novel complex [Ag(NIT3Py)3]?(ClO4)(H2O) has been synthesized and structurally characterized by X-ray diffraction method. It crystallizes in the rhombohedral system, space group R 3 with a = 15.8227(17), b = 15.8227(17), c = 31.445(3) ?, γ = 120°, V = 6817.8(12) ?3, Dc = 1.370 g/cm3, Z = 6, μ = 0.566 mm-1, Mr = 937.18, F(000) = 2916, R = 0.0715, wR = 0.2115 and GOF = 1.086. The structure consists of Ag(NIT3Py)3+ cation moiety, one water molecule and one perchloric ion. The Ag(I) ion is in a trigonal planar coordination environment formed by three nitrogen atoms from three NIT3Py ligand molecules.

关键词： crystal structure nitronyl nitroxide radical Ag(I) complex magnetism ferromagnetic interactions