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Analysis of the Hydraulic and Heat Transfer Evolution Mechanism of a Single Rock Fracture

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Journal of Earth Science 2023年第1期34卷 205-213页

作者： Biao Shu Fan zeng John Kemeny Runjun Zhu Keping Chen Jingqiang Tan Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University) Ministry of EducationSchool of Geosciences and Info-PhysicsCentral South UniversityChangsha410083China Department of Mining and Geological Engineering University of ArizonaTucson85719USA

Mineral dissolution and mechanical deformation of granite are two main mechanisms that affect permeability evolution of rock *** this study,two water flow-through experiments with large granite fractures were conducted at 200 0C with a constant flow rate for 24 h,under confining pressures of 5 and 10 MPa,*** pressure and temperature were measured,fracture aperture and permeability were calculated,and chemical element concentrations in effluent water were tested for mechanism *** permeability fluctuates up and down between 2.62 × 10^(-12)and 3.16 ×10^(-12)m^(2)at confining pressure of 5 MPa;while it decreased monotonously by 24% from 1.92 × 10^(-12)to1.45 × 10^(-12)m^(2)at a confining pressure of 10 *** heat transfer rates at both experiments stay stable at about 0.25 J/*** mass concentration of Ca,Na,K,and Si in effluent water are between 5 to 23mg/L,indicating slight dissolution of Ca-plagioclase,Na-plagioclase,and K-feldspar,as well as possible precipitation of minor amount of kaolinite or *** total amount of free-face dissolution and pressure dissolution are similar at 5 and 10 *** geochemical reaction counts for only small part of the aperture change,while the mechanical deformation counts the major part of the aperture change.

关键词： geothermal energy permeability heat transfer confining pressure hydraulic aperture

Comparison of antimony and arsenic behaviour at the river-lake junction in the middle of the Yangtze River Basin

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Journal of Environmental Sciences 2024年第2期136卷 189-200页

作者： Huiji Liu Wei zeng Ziyang Lai Mengchang He Chunye Lin Wei Ouyang Xitao Liu State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087China

As typical metalloid toxic elements widely distributed in environmental media,the geochemical behaviour of antimony(Sb)and arsenic(As)affects environmental *** selected the surface waters and sediments at the river-lake junction of Dongting Lake as the research objects,analysed the concentration and chemical partitioning of Sb and As,assessed its contamination and ecological risk levels,and discussed its sources and potential influencing *** concentrations of dissolved Sb and As in surface waters were low(<5.46μg/L),and the concentrations of Sb and As in surface sediments were 2.49-22.65mg/kg and 11.10-136.34 mg/kg,*** and As in sediments were mainly enriched in the fraction of residues,but the proportion of As in bioavailability was significantly higher than that of *** the contamination level of Sb was higher than that of As,the risk assessment code(RAC)showed that the ecological risk level of As was higher than that of *** erosion and mining activities(in the midstream of Zijiang River)were the main contaminated sources of Sb,while As was affect mainly by rainwater *** contamination and ecological risk of Sb in the inlet of the Zijiang River should receive considerable attention,while those of As in the inlet of the Xiangjiang River should also be seriously *** study highlights the need for multi-index-based assessments of contamination and ecological risk and the importance of further studies on the environmental behaviour of metalloids in specific hydrological conditions,such as river-lake junctions.

关键词： Contamination Ecological risks Antimony(Sb) Arsenic(As) River-lake junction Dongting Lake

Luminescence mechanism and energy level structure of Eu-doped GaN powders investigated by cathodoluminescence spectroscopy

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Science China(Physics,Mechanics & Astronomy) 2014年第4期57卷 628-631页

作者： WANG xiaoDan zeng XiongHui XU Ke MAO HongMin MA ChunLan Department of Physics Suzhou University of Science and Technology Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences

1.5at% Eu-doped GaN powders were prepared by a co-precipitation *** X-ray diffraction(XRD)results shows that there is only the wurtzite *** spectra were measured at room temperature and liquid nitrogen temperature,*** band-to-band luminescence of GaN was shifted from 373 nm to 368 nm with the temperature decreasing from room temperature to liquid nitrogen *** luminescence peaks at 537,557,579,590,597,614,653 and 701 nm are attributed to the Eu ions related transitions in the host of GaN powders and the peak positions were not influenced by the variation of *** the increase of accelerating voltage,the intensity of all luminescence peaks was *** strongest luminescence peak at 614 nm shows non-symmetrical shape and is composed of 612,615 and 621 nm through Lorentzian fitting,which indicates there are oxygen and nitrogen environments of the Eu3+ions in the Eu-doped GaN powders.

关键词： Eu GaN energy level spectrum

MoNi_(4)-NiO heterojunction encapsulated in lignin-derived carbon for efficient hydrogen evolution reaction

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Green Energy & Environment 2023年第6期8卷 1728-1736页

作者： Yanlin Qin Yunzhen Chen Xuezhi zeng Yingchun Liu Xuliang Lin wenli Zhang Xueqing Qiu School of Chemical Engineering and Light Industry Guangdong University of Technology100 Outer Ring West RoadGuangzhou University CityPanyu DistrictGuangzhou510006China Guangdong Provincial Key Laboratory of Plant Resources Biorefinery Guangdong University of Technology100 Outer Ring West RoadGuangzhou University CityPanyu DistrictGuangzhou510006China

Molybdenum nickel alloy has been proved to be an efficient noble-metal-free catalyst for hydrogen evolution reaction(HER) in alkaline medium, but its electrocatalytic activity and stability need to be further improved to meet industrial requirements. In this study, carboxymethylated enzymatic hydrolysis lignin(EHL) was used as a biomacromolecule frame to coordinate with transition metal ions and reduced by pyrolysis to obtain the MoNi_(4)-NiO heterojunction(MoNi_(4)-NiO/C). The oblate sphere structure of MoNi_(4)-NiO/C exposed a large catalytic active surface to the electrolyte. As a result, the hydrogen evolution reaction of MoNi_(4)-NiO/C displayed a low overpotentials of 41 mV to achieve 10 mA cm-2and excellent stability of 100 h at 100 mA cm^(-2)in 1 mol L^(-1)KOH, which was superior to that of commercial Pt/C. Lignin assisted the formation of NiO to construct the MoNi_(4)-NiO interface and MoNi_(4)-NiO heterojunction structure, which reduced the energy barrier by forming a more favorable transition states and then promoted the formation of adsorbed hydrogen at the heterojunction interface through water dissociation in alkaline media, leading to the rapid reaction kinetics. This work provided an effective strategy for improving the electrocatalytic performance of noble-metal-free electrocatalysts encapsulated by lignin-derived carbon.

关键词： Lignin-derived carbon Hydrogen evolution reaction MoNi_(4)–NiO interface Electrocatalysis

Reaction kinetics during direct alloying of manganese ore cored wire

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Journal of Iron and Steel Research International 2020年第3期27卷 282-294页

作者： Wei Wu Qi Gao Bo Zhang Hua-dong Meng Lu Lin Jia-qing zeng Metallurgical Technology Research Department Central Iron and Steel Research InstituteBeijing 100081China State Key Laboratory of Refractory and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

In order to increase the reaction rates between the molten steel and the slag and cut down the reduction time when the top slag of manganese ore is added into the molten steel,a method of directly alloying manganese ore has been experimented in a 500-kg induction *** results show that the manganese yield is greater than 90%when the wire feeding method is *** manganese yield is 43.26%within 1 *** contrast,the manganese yield for the top-slag adding process is only 10.98%for the same *** mass transfer rate of the manganese is greater in the molten steel than in the slag,and the limiting factor is the mass transfer rate of the manganese in the slag in the period of 10-30 *** slag composition area is closer to the area of high melting point for the wire feeding method than for the top-slag adding *** the slagging process,refining slag composed of C a O and SiO:is formed after 15 min;after 25-30 min,refining slag with a high basicity is formed and consists of CaO,SiO2 and Al203.

关键词： Manganese ore Cored wire Direct alloying process Reaction kinetics Mass transfer rate

Hybrid assembly of conducting nanofiber network for ultra-stretchable and highly sensitive conductive hydrogels

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Journal of Materials Science & Technology 2024年第2期169卷 1-10页

作者： Yalei Wang Shulong zeng Shaohong Shi Yuheng Jiang Zhiwei Du Bingzhen Wang Xiurong Li State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures School of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan UniversityChengdu 610065China

Conductive hydrogels have attracted extensive attention owing to their promising application prospects in flexible and wearable ***,achieving both high sensitivity and mechanical robustness remains ***,a novel and versatile conductive hydrogel based on the hybrid assem-bly of conductive cellulose nanofiber(CNF)networks has been designed and *** by the templating effect of CNFs and stabilizing effect of negatively charged poly(styrene sulfonate)(PSS),conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)was self-organized into three-dimensional nanostructures which constructed a robust conductive network after in-situ oxidative *** unique structure derived from CNF bio-template endowed polyacrylamide(PAM)hydrogels with improved electrical conductivity and excellent mechanical *** a result,the as-fabricated CNF/PEDOT:PSS/PAM hydrogel exhibited an ultimate tensile strain of 1881%and toughness of 3.72 MJ/m^(3),which were 4.07 and 8.27 times higher than the CNF-free hydrogel,*** significantly,the resultant hydrogel sensor showed highly desirable sensing properties,including remarkable sensing range(1100%),high gauge factor(GF=5.16),fast response time(185 ms),and commendable durability,as well as good ***,the hydrogel sensor was able to distinguish subtle physiological activities including phonation and facial expression,and monitor large human body motions such as finger flexion and elbow ***,it was feasible to integrate the strain sensor on the joints of robots to recognize complicated machine motion signals,showing potential in advanced human-machine interactions.

关键词： Strain sensor Cellulose nanofibers PEDOT:PSS Conductive hydrogel Templating method

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一类单种群模型的全局稳定性

中北大学学报（自然科学版） 2006年第2期27卷 171-174页

作者：魏福义曾文才华南农业大学理学院广东广州510642

用种群动力学的方法对单种群数学模型N=。N d(q+pN+N3)(其中p,q,d为实数且d<0)进行了研究,得到了该模型的稳定性条件,给出了相应条件下的平衡点和吸引域.该结论可以推广到单种群数学模型N=。N d(a+bN+cN2+N3)之中.

关键词：稳定性平衡点吸引域

Surfactant-assisted removal of 2,4-dichlorophenol from soil by zero-valent Fe/Cu activated persulfate

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Chinese Journal of Chemical Engineering 2022年第4期35卷 447-455页

作者： Ling Xu Ji Li wenbin zeng Kai Liu Yibing Ma Liping Fang Chenlu Shi Faculty of Material Science and Chemistry China University of GeosciencesWuhan 430074China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management Institute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangzhou 510650China Macao Environmental Research Institute Macao University of Science and TechnologyTaipaMacaoChina

The organic compounds contaminated soil substantially threatens the growth of plants and food *** this study,we synthesis zero-valent bimetallic Fe/Cu catalysts for the degradation of 2,4-dichlorophenol(DCP)in soils with persulfate(PS)in combination of organic surfactants and exploring the main environmental impact *** kinetic experiments show that the 5%(mass)dosage of Fe/Cu exhibits a higher degradation efficiency(86%)of DCP in soils,and the degradation efficiency of DCP increases with the increase of the initial PS *** conditions are favorable for the DCP degradation in *** importantly,the addition of Tween-80,and Triton-100 can obviously desorb DCP from the soil surface,which enhances the degradation efficiency of DCP in soils by Fe/Cu and PS reaction ***,the Quenching experiments demonstrate that SO_(4)^(-1)·and·OH are the predominant radicals for the degradation of DCP during the Fe/Cu and PS reaction system as well as non-radical also *** findings of this work provide an effective method for remediating DCP from soils.

关键词： Zero-valent iron and copper Advanced oxidation process Persulfate Chlorinated organic pollutants Surfactant

Jatropha curcas L. oil extracted by switchable solvent N, N-dimethylcyclohexylamine for biodiesel production

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Chinese Journal of Chemical Engineering 2016年第11期24卷 1640-1646页

作者： Shanjin zeng Chuandong Tao Richard Parnas Wei Jiang Bin Liang Yingying Liu Houfang Lu College of Chemical Engineering Sichuan University Chengdu 610065 China Institute of New Energy and Low Carbon Technology Sichuan University Chengdu 610065 China Institute of Materials Science Univ. of Connecticut Storrs. CT06269-3136 USA

Biodiesel, which is a renewable and environmentally friendly fuel, has been studied widely to help remedy increasing environmental problems. One of the key processes of biodiesel production is oil extraction from oilseed materials. Switchable solvents can reversibly change from molecular to ionic solvents under atmospheric CO_2,and can be used for oil extraction. N, N-dimethylcyclohexylamine(DMCHA), a switchable solvent, was used to extract oil from Jatropha curcas L. oil seeds to produce biodiesel. The appropriate extraction conditions were:1:2 ratio of seed mass to DMCHA volume, 0.3–1 mm particle size, 200 r·min-1agitation speed, 60 min extraction time, and 30 °C extraction temperature. The extraction ratio was about 83%. This solvent extracted the oil more efficiently than hexane, and is much less volatile. By bubbling CO_2 under 1 atm and 25 °C for 5 h, the oil was separated, and DMCHA was recovered after releasing CO_2 by bubbling N_2 under 1 atm and 60 °C for 2 h. The residual solvent content in oil was about 1.7%. Selectivity of DMCHA was evaluated by detecting the protein and sugar content in oil. Using the oil with residual solvent to conduct transesterification process, the oil conversion ratio was approximately 99.5%.

关键词： Jatrapha curcus L. oil Extraction N N-dimethylcyclohexylamine Switchable hydrophilic solvent Biodiesel