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Resonant-Superlinear Nonhomogeneous Dirichlet Problems

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Acta Mathematica Sinica,English Series 2023年第11期39卷 2091-2116页

作者： zhen hai liu Nikolaos S.PAPAGEORGIOU Center for Applied Mathematics of Guangxi Yulin Normal UniversityYulin 537000P.R.China Guangxi Key Laboratory of Universities Optimization Control and Engineering Calculation College of Mathematics and PhysicsGuangxi Minzu UniversityNanning 530006P.R.China Department of Mathematics National Technical UniversityZografou Campus15780 AthensGreece

We consider a Dirichlet nonlinear equation driven by the(p,2)-Laplacian and with a reaction having the competing effects of a parametric asymmetric superlinear term and a resonant *** show that for all small values of... 详细信息

关键词： Asymmetric reaction resonance superlinear term nonlinear regularity comparison principle critical groups solutions with sign information

Differential Evolution Hemivariational Inequalities with Anti-periodic Conditions

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1143-1160页

作者： Jing ZHAO Chun Mei GAN zhen hai liu School of Mathematics and Quantitative Economics Guangxi University of Finance and EconomicsNanning 530003P.R.China Guangxi Colleges and Universities Key Laboratory of Optimization Control and Engineering Calculation Guangxi Minzu UniversityNanning 530006P.R.China

The goal of this paper is to deal with a new dynamic system called a differential evolution hemivariational inequality(DEHVI)which couples an abstract parabolic evolution hemivariational inequality and a nonlinear differential equation in a Banach ***,by apply ing surjectivity result for pseudomonotone multivalued mappins and the properties of Clarke's subgradient,we show the nonempty of the solution set for the parabolic hemivariational ***,some topological properties of the solution set are established such as boundedness,closedness and ***,we explore the upper semicontinuity of the solution ***,we prove the solution set of the system(DEHVI)is nonempty and the set of all trajectories of(DEHVI)is weakly compact in C(I,X).

关键词： Differential parabolic hemivariational inequality Clarke subdifferential hyperbolicparabolic system parabolic-parabolic system existence result

Inverse Coefficient Problems for Nonlinear Parabolic Differential Equations

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Acta Mathematica Sinica,English Series 2008年第10期24卷 1617-1624页

作者： Yun Hua OU Alemdar HASANOV zhen hai liu Department of Mathematics Hu'nan University of Technology Zhuzhou Hu'nan 412007 P. R. China Applied Mathematical Sciences Research Center Kocaeli University Izmit-Kocaeli 41300 Turkey Department of Mathematics Central South University Changsha 410075 P. R. China

This paper is devoted to a class of inverse problems for a nonlinear parabolic differential equation. The unknown coefficient of the equation depends on the gradient of the solution and belongs to a set of admissible coefficients. It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence. Based on this result the existence of a quasisolution of the inverse problem is obtained in the appropriate class of admissible coefficients.

关键词： Parabolic equations Inverse coefficient problems Existence of quasisolutions

Improved hydrogen storage properties of LiBH4 confined with activated charcoal by ball milling

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Rare Metals 2019年第4期38卷 321-326页

作者： He Zhou Xin-Hua Wang hai-zhen liu Shi-Chao Gao Mi Yan State Key Laboratory of Silicon Materials School of Materials Science & Engineering Zhejiang University Hangzhou 310027 China State Key Laboratory of Advanced Transmission Technology Global Energy Interconnection Research Institute State Grid Corporation of China Beijing 102209 China

In order to enhance the hydrogen storage properties of LiBH4,activated charcoal (AC) was used as the scaffold to confine LiBH4 in this *** milling was used to prepare LiBH4/AC *** results show that dehydrogenation properties of ball-milled LiBH4/AC (LiBH4/AC-BM) are greatly improved compared with that of pristine LiBH4,ball-milled LiBH4 (LiBH4-BM) and hand-milled LiBH4/AC (LiBH4/AC-HM).The onset dehydrogenation temperature of LiBH4 for LiBH4/AC-BM is around 160 ℃,which is 170 ℃ lower than that of pristine *** around 400 ℃,LiBH4/AC-BM finishes the dehydrogenation with a hydrogen capacity of 13.6 wt%,which is approximately the theoretical dehydrogenation capacity of pure LiBH4 (13.8 wt%),while the dehydrogenation processes for LiBH4-BM and LiBH4/AC-BM do not finish even when they were heated to 600 ℃.The isothermal dehydriding measurements show that it takes only 15 min for LiBH4/AC-BM to reach a dehydrogenation capacity of 10.1 wt% at 350 ℃,whereas the pristine LiBH4 and the LiBH4/AC-HM release hydrogen less than 1 wt% under the same *** dehydrogenation process and the effect of AC were discussed.

关键词： Hydrogen storage properties Hydrogen storage materials Lithium borohydride Activated charcoal

Recent advances in metastable alloys for hydrogen storage:a review

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Rare Metals 2022年第6期41卷 1797-1817页

作者： Huai-Jun Lin Yan-Shan Lu liu-Ting Zhang hai-zhen liu Kaveh Edalati Adám Révész Institute of Advanced Wear and Corrosion Resistance and Functional Materials Jinan UniversityGuangzhou 510632China Guangdong Provincial Key Laboratory of Advance Energy Storage Materials South China University of TechnologyGuangzhou 510640China School of Materials and Energy Guangdong University of TechnologyGuangzhou 510006China School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Guangxi Novel Battery Materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Processing for Non-Ferrous Metallic and Featured Materials Guangxi UniversityNanning 530004China International Institute for Carbon-Neutral Energy Research(WPI-I2CNER) Kyushu UniversityFukuoka 819-0395Japan Department of Materials Physics E?tv?s UniversityBudapest 1518Hungary

Development of new materials with high hydrogen storage capacity and reversible hydrogen sorp-tion performances under mild conditions has very high value in both fundamental and application *** the past years,some new systems with metastable structures,such as ultra-fine nanocrystalline alloys,amorphous alloys,nanoglass alloys,immiscible alloys,high-entropy alloys,have been abundantly studied as hydrogen storage *** new hydrogen storage properties either from the kinetics or thermodynamics aspects have been *** this review,recent advances of studies on metastable alloys for hydrogen storage applications have been comprehensively *** materials preparation methods to synthesize metastable hydrogen storage alloys are firstly ***,hydrogen storage prop-erties of the metastable alloys are summarized and dis-cussed,focusing on the unique kinetics and thermodynamics properties by forming of such unique metastable *** examples,superior hydrogena-tion kinetics and higher hydrogen storage capacity have been achieved in Mg-based amorphous and nanoglass *** thermodynamics properties can be obtained in the immiscible Mg-Mn and Mg-Zr *** addition to highlighting the recent achievements of metastable alloys in the field of hydrogen storage,the remaining challenges and trends of the emerging research are also discussed.

关键词： Hydrogen storage Metastable alloys Kinetics Thermodynamics

Hydrogen storage properties of Nb-compounds-catalyzed LiBH4-MgH2

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Rare Metals 2017年第9期36卷 723-728页

作者： He Zhou hai-zhen liu Lou Xu Shi-Chao Gao Xin-Hua Wang Mi Yan State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Advanced Transmission Technology Global Energy Interconnection Research Institute State Grid Corporation of ChinaBeijing 102209China

In order to improve the hydrogen storage properties of LiBH4-MgH2 composite, two different kinds of Nb-based catalysts, NbC and NbF5, were added to LiBH4-MgH2 composite by ball milling, and the effect of catalysts on hydrogen storage properties of the modified LiBH4-MgH2 system was investigated. The experimental results show that LiBH4-MgH2 composite is a two-step dehydrogenation process, and Nb-based compounds can remarkably enhance its dehydrogenation kinetics. For the composite without addition of catalysts, the starting decomposition temperature for the first dehydrogenation step is around 320℃, and there is a long period of incubation time（around 220 min） for the occurrence of the second decomposition step even at high temperature of 450℃. It needs more than 10 h to complete the decomposition process and release around 9 wt% H2. After addition of 5 mol% NbF5, the starting decomposition temperature for the first dehydrogenation step is around 150℃, there is no incubation time for the second decomposition step, and it takes around 40 min to complete the second step and reaches a total dehydrogenation capacity of 9.5 wt%. NbF5 has better catalytic effect than NbC. Based on the hydrogenation/dehydrogenation behaviors and structural variation, the mechanism of catalytic effect was discussed.

关键词： Hydrogen storage properties Hydrogen storagematerials Lithium borohydride Magnesium hydride

Cycling hydrogen desorption properties and microstructures of MgH_(2)-AlH_(3)-NbF_(5) hydrogen storage materials

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Rare Metals 2021年第4期40卷 1003-1007页

作者： Xiao-Sheng liu hai-zhen liu Ning Qiu Yan-Bing Zhang Guang-Yao Zhao Li Xu Zhi-Qiang Lan Jin Guo Guangxi Novel Battery Materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Processing for Non-ferrous Metallic and Featured Materials School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research Institute Co.LtdBeijing 102209China Department of AC Construction State Grid Co.LtdBeijing 100031China State Grid DC Project Construction Branch Company Beijing 100052China

Magnesium hydride(MgH_(2)) is a candidate material for hydrogen ***_(2)-AlH_(3) composite shows superior hydrogen desorption properties than pure MgH_(2).However,this composite still suffers from poor cycling *** this work,NbF_(5) was utilized to improve the cycling properties of the MgH_(2)-AlH_(3) *** hydrogen desorption studies show that NbF_(5) significantly improves the cycling stability of MgH_(2)-AlH_(3).The MgH_(2)-AlH_(3)-NbF_(5) composite can release about 2.7 wt% of hydrogen at 300℃ for 1 h and the hydrogen desorption capacity can maintain at 2.7 wt% for more than100 *** comparison,the hydrogen desorption capacity of the MgH_(2)-AlH_(3) composite is decreasing with the cycle number *** capacity is reduced from a maximum value of 3.3 wt% to about 1.0 wt% after 40 ***-Emmett-Teller(BET) surface area measurements show that the particle size of MgH_(2)-AlH_(3) composite decreases after cycling,which means pulverization of the ***_(5) can to some extent suppress the pulverization of the composite during cycling,which partially contributes to the improvement of the cycling hydrogen desorption properties of the material.

关键词： Hydrogen storage materials Magnesium hydride Aluminum hydride Niobium fluoride Cycling properties

On Doubly Degenerate Quasilinear Parabolic Equations of Higher Order

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Acta Mathematica Sinica,English Series 2005年第1期21卷 197-208页

作者： zhen hai liu Department of Mathematics,Changsha University of Science and Technology Changsha 410077,P.R.China Department of Mathematics Changsha University of Science and Technology Changsha 410077 P. R. China

We deal with the existence of periodic solutions for doubly degenerate quasilinear parabolic equations of higher order,which can degenerate,on a part of the boundary,on a segment in the interior of the domain and in t... 详细信息

关键词： Double degeneration Quasilinear parabolic equations Periodic solutions

Improvement in hydrogen storage performance of MgH_(2) by vanadium doped with ZIF-8 derived a single-atom catalyst V-N-C

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Rare Metals 2024年第6期43卷 2623-2635页

作者： Fei-Fan Hong Wei-Tao Shi Ruo-Lin Zhao Yi Fan Zi-Qi liu Si-Zhi Ding hai-zhen liu Wen-zheng Zhou Jin Guo Zhi-Qiang Lan Guangxi Novel Battery Materials Research Center of Engineering Technology and Center on Nanoenergy Research Guangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China Nanning Engineering Technology Research Center for Power Transmission System of New Energy Vehicle Transportation CollegeNanning UniversityNanning 530200China

Herein,the successful preparation of a singleatom catalyst V-N-C using vanadium-doped zeolitic imidazolate framework(ZIF)-8 as a precursor is *** experimental results showed that the V-N-C had a good promoting effect on the hydrogen storage performance of MgH_(2),and the optimal addition amount of V-N-C was 10wt%.The hydrogenation and dehydrogenation apparent activation energies of 10 wt%V-N-C-catalyzed MgH_(2)were reduced by 44.9 and 53.5 kJ·mol^(-1),respectively,compared to those of additive-free MgH_(2).The 10 wt%V-N-C-catalyzed MgH_(2)could reabsorb 5.92 wt%of hydrogen in 50 min at 150℃,with a capacity retention rate of 99.1%after 30 cycles of hydrogen absorption and *** analysis showed that V-N-C was partially transformed into VN and metallic V when it was milled with MgH_(2);the in-situ-formed VN and metallic V played an important role in improving the hydrogen storage performance of MgH_(2).This approach provides a potential solution for obtaining high-performance Mg-based hydrogen storage materials through synergistic interactions between V,N and C.

关键词： MgH_(2) Hydrogen storage materials Catalyst Hydrogen storage perormance