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Journal of Mountain Science 2013年第3期10卷 464-471页

作者： Deepak DHYANI Shalini DHYANI RK MAIKHURI G.B.Pant institute of Himalayan Environment and development Garhwal UnitSrinagar GarhwalUttarakhandIndia

Natural habitat ofHippophae salicifolia in Central Himalaya is continuously being degraded due to habitat destruction and harvesting. Although logging is prohibited, habitat destruction has increased because of regular road construction, repairing and broadening activities. In addition, Hippophae resources are continuously being harvested by lopping （both partial and complete） for fuelwood, fodder and fruits in higher Himalayan region. This paper presents a detailed analysis of relationship between density, demographic structure, and harvesting of H. salicifolia growing pockets in the five major valleys （Gangotri, Yamunotri, Niti, Mana and Bhyundhar） of Uttarakhand in Central Himalaya, India. A total of 12o quadrats were laid randomly to study population structure, regeneration, sex ratio and lopping using quadrats of lOO m2 （a4 in each valley） in Hippophae growing patches. Our study shows that the density, size distribution, and regeneration of Hippophae vary considerably among the major valleys. Trees in the Yamunotri valley have the highest density of large trees but the lowest density of seedlings. In contrast, there are few large trees but many seedlings in the Mana valley. The number and size of lopped trees also varied among the valleys. Lopping was greatest in Bhyundhar （11.4%） and Yamunotri （19.7%） and least in Niti （3.9%）. The size of lopped trees differed substantially as well. In Bhyundhar, the largest trees were taken while saplings were taken in Yamunotri. Our study revealed that unsustainable harvesting from plants for fuel, fencing and fruits along with road broadening activities in Central Himalaya are the main cause ofhabitat destruction. Our research highlights the urgent need for in-situ and ex-situ conservation of Hippophae salicifolia so that it＇s potential can be harnessed sustainably by rural hill societies for their socio-economic development.

关键词： Central Himalaya Seabuckthorn Dioecious Disturbance Habitat Conservation

Three-dimensional fracture of UO2 ceramic pellets by phase field modeling

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 169-180页

作者： Wei Xiong Xuan Ye Hongzhang Cheng Xiaoming Liu institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

Fracture is the primary failure type for the UO2ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional （3D） UO2ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

Nanostructure and Formation Mechanism of Pt-WO_3/C Nanocatalyst by Ethylene Glycol Method

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Journal of Wuhan University of Technology(Materials Science) 2011年第3期26卷 377-383页

作者：吴锋吴川 School of Chemical Engineering and Environment Beijing Institute of Technology National development Center for High Technology Green Materials

Pt-WO3 nanoparticles uniformly dispersed on Vulcan XC-72R carbon black were prepared by an ethylene glycol *** morphology,composition,nanostructure,electrochemical characteristics and electrocatalytic activity were characterized,and the formation mechanism was *** average particle size was 2.3 nm,the same as that of Pt/C *** W/Pt atomic ratio was 1/20,much lower than the design of 1/*** deposition of WO3·xH2O nanoparticles on Vulcan XC-72R carbon black was found to be very difficult by *** XPS and XRD,the Pt nanoparticles were formed in the colloidal solution of Na2WO4,the EG insoluble Na2WO4 resulted in the decreased relative crystallinity and increased crystalline lattice constant compared with those of Pt/C catalyst and,subsequently,the higher specific electrocatalytic activity as determined by *** Pt-mass and Pt-electrochemically-active-specific-surface-area based anodic peak current densities for ethanol oxidation were 422.2 mA·mg-1Pt and 0.43 mA·cm-2Pt,1.2 and 1.1 times higher than those of Pt/C catalyst,respectively.

关键词： Pt-based catalyst tungsten oxide ethylene glycol method fuel cell

Constant Volume Spray Auto-ignition Study of Alkanes

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China Petroleum Processing & Petrochemical Technology 2019年第1期21卷 71-79页

作者： Wang Jun Yang He Song Haiqing Tian Huayu Wang Pengfei SINOPEC research institute of Petroleum Processing

Spray auto-ignition experiments were carried out in a constant volume combustion chamber for some pure alkanes(n-paraffins with different chain length, cyclohexane, n-butyl cyclohexane, and isooctane) and blends of n-decane with Standard Blended fuel(isooctane/n-heptane) and product gasoline. Test results showed that the reaction activity of n-paraffins was relatively high. Meanwhile, the auto-ignition characteristics differed significantly with the molecular structures of alkanes. Adding different volume fractions of n-decane to Standard Blended fuel and product gasoline could improve the fuel reaction activity at varying degree. Finally, functional groups effects were used to simulate the relationship between the molecular topology and the auto-ignition quality.

关键词： spray auto-ignition reaction activity functional group alkane

Cathode Design for Proton Exchange Membrane fuel Cells in Automotive Applications

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Automotive Innovation 2021年第2期4卷 144-164页

作者： Haojie Wang Ruiqing Wang Sheng Sui Tai Sun Yichang Yan Shangfeng Du School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China institute of fuel Cells Shanghai Jiao Tong UniversityShanghai 200240China research institute of Rare Metals Guangdong Academy of SciencesGuangzhou 510650GuangdongChina School of Chemical Engineering University of BirminghamBirmingham B152TTUK

An advanced cathode design can improve the power performance and durability of proton exchange membrane fuel cells(PEMFCs),thus reducing the stack cost of fuel cell vehicles(FCVs).Recent studies on highly active Pt alloy catalysts,short-side-chain polyfluorinated sulfonic acid(PFSA)ionomer and 3D-ordered electrodes have imparted PEMFCs with boosted power *** achieve the compacted stack target of 6 kW/L or above for the wide commercialization of FCVs,developing available cathodes for high-power-density operation is critical for the ***,current developments still remain extremely challenging with respect to highly active and stable catalysts in practical operation,controlled distribution of ionomer on the catalyst surface for reducing catalyst poisoning and oxygen penetration losses and 3D(three-dimensional)-ordered catalyst layers with low Knudsen diffusion losses of oxygen *** review paper focuses on impacts of the cathode development on automotive fuel cell systems and concludes design directions to provide the greatest benefit.

关键词： fuel cell vehicle(FCV) Proton exchange membrane fuel cell(PEMFC) Cathode Mass transport Ionomer

Production,activation,and applications of biochar in recent times

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Biochar 2020年第3期2卷 253-285页

作者： Anil Kumar Sakhiya Abhijeet Anand Priyanka Kaushal Center for Rural development and Technology Indian Institute of Technology-DelhiNew Delhi 110016India

Biomass is a green energy source and is available in *** is a carbon-rich material derived from a wide range of biomass or organic waste through the thermochemical *** has received increasing attention because of its distinctive properties such as high carbon content,greater specific surface area,cation exchange capacity,nutrient retention capacity,and stable *** review paper extensively studies and reports the different pyrolysis processes,reactor types,the effect of process parameters on biochar yield,and its physicochemical properties,biochar activation methods,and *** also details the status of the research and development(R&D)progress in biochar production through conventional and advanced *** study found that unlike many products(at R&D stage)biochar has high potential to scale up and has a direct impact on crop yield,water purification(for domestic and industrial application),alternative fuels(clean solid fuel for cookstove),air purification,catalyst,biogas production,purification,and *** addition,the paper lists the merits and challenges in the novel biochar applications like hydrogen storage,electrochemical capacitor,and fuel cell technology.

关键词： Biomass Pyrolysis Biochar Application Review

Production of Integrated Automotive Part in High Pressure Diecasting Process Using Salt Core

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Journal of Rare Earths 2004年第Z2期22卷 57-60页

作者： Ki-Bae Kim Hyun-Kwang Seok Jun-Su Kim Advanced Materials research Center Korea Institute of Science and TechnologyP.O.Box 131CheongryangSeoul130-650Korea Advanced Materials Research CenterKorea Institute of Science and TechnologyP.O.Box 131CheongryangSeoul130-650Korea Research & Development CenterTechnology Union Co.Ltd742-1Paeksok-dongChonan-siChungchongnam-do330-220Korea

A new concept of salt core, a melting temperature of which is lower than the solidus temperature of cast alloy,was introduced to produce an integrated casting part having a complicated inner shape or requiring under-cut in high pressure die casting or squeeze casting process. A salt core, named a fusible core in this paper because the salt core can be easily extracted just as holding at a temperature under a solidus temperature of a casting alloy, was developed and applied to produce a fuel control part for automotive GDI engine in high pressure diecasting machine. A different salt material of a lower melting temperature than that of A1 alloy was mixed with a different ceramic particulate to improve a thermo-physical property of fusible core. The thermo-physical property of the fusible core was measured and a weight faction of the ceramic particulate was optimized. The selected core materials were poured in metallic mold by gravity to produce a fusible core for a fuel control part for automotive GDI engine. The fuel control part, which the fusible core was included inside, was successful to fabricate in a conventional diecasting machine with no melting of fusible core during casting.

关键词： salt core high pressure diecasting casting part for automotive fusible core

Intelligent and ecological coal mining as well as clean utilization technology in China: Review and prospects

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International Journal of Mining Science and Technology 2019年第2期29卷 161-169页

作者： Guofa Wang Yongxiang Xu Huaiwei Ren Mining institute China Coal Research Institute Coal Mining and Designing Department Tiandi Science & Technology Co. Ltd. State Key Laboratory of Coal Mining and Clean Utilization China Coal Research Institute

Coal is an essential fossil fuel in China; however, coal mining and its utilization are being under the increasing pressure from ecological and environmental protection. Therefore, the consulting project "Technical Revolution in Ecological and Efficient Coal Mining and Utilization & Intelligence and Diverse Coordination of Coal-based Energy System," initiated by Chinese Academy of Engineering, puts forward three stages(3.0, 4.0 and 5.0) of China's coal industry development strategy. Aimed at "reduced staff,ultra-low ecological damage, and emission level near to natural gas," breakthroughs should be achieved in the following three key technologies during the China Coal Industry 3.0 stage(2016–2025): including intelligent coal mining, ecological mining, ultra-low emission and environmental protection. This paper focuses on the development trends of the China Coal Industry 3.0 and its support for China Coal Industry 4.0 and 5.0 is analyzed and prospected as well, which may offer technical assistance and strategy orientation for realizing the transformation from traditional coal energy to clean energy.

关键词： Intelligent mining Ecological mining Clean utilization Environmental protection China’s coal industry

A perspective on influences of cathode material degradation on oxygen transport resistance in low Pt PEMFC

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Nano research 2023年第1期16卷 377-390页

作者： Huiyuan Li Xiaojing Cheng Xiaohui Yan Shuiyun Shen Junliang Zhang institute of fuel Cells School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China MOE Key Laboratory of Power&Machinery Engineering Shanghai Jiao Tong UniversityShanghai 200240China

A large-scale industrial application of proton exchange membrane fuel cells(PEMFCs)greatly depends on both substantial cost reduction and continuous durability ***,compared to effects of material degradation on apparent activity loss,little attention has been paid to influences on the phenomena of mass *** this review,influences of the degradation of key materials in membrane electrode assemblies(MEAs)on oxygen transport resistance in both cathode catalyst layers(CCLs)and gas diffusion layers(GDLs)are comprehensively explored,including carbon support,electrocatalyst,ionomer in CCLs as well as carbon material and hydrophobic polytetrafluoroethylene(PTFE)in *** is analyzed that carbon corrosion in CCLs will result in pore structure destruction and impact ionomer distribution,thus affecting both the bulk and local oxygen transport *** the catalyst degradation,an eventual decrease in electrochemical active surface area(ECSA)definitely increases the local oxygen transport resistance since a decrease in active sites will lead to a longer oxygen transport *** is also noted that problems concerning oxygen transport caused by the degradation of ionomer chemical structure in CCLs should not be *** cation contamination and chemical decomposition will change the structure of ionomer,thus worsening the local oxygen ***,it is found that the loss of carbon and PTFE in GDLs lead to a higher hydrophilicity,which is related to an occurrence of water flooding and increase in the oxygen transport resistance.

关键词： proton exchange membrane fuel cells(PEMFC) oxygen transport resistance degradation cathode catalyst layer gas diffusion layer