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Current Research Progress in Magnesium Borohydride for Hydrogen Storage(A review)

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Progress in Natural Science:Materials International 2021年第6期31卷 809-820页

作者： Yujie lv Ying Wu School of Energy Power and Machinery Engineering North China Electric Power University Advanced Materials Research Institute North China Electric Power University Central Iron & Steel Research Institute Advanced Technology & Materials Co. Ltd Jiangsu JITRI Advanced Energy & Materials Research Institute Co. Ltd

Hydrogen storage in solid-state materials is believed to be a most promising hydrogen-storage technology for high efficiency, low risk and low cost. Mg(BH)is regarded as one of most potential materials in hydrogen storage areas in view of its high hydrogen capacities(14.9 wt% and 145–147 kg cm). However, the drawbacks of Mg(BH)including high desorption temperatures(about 250°C–580°C), sluggish kinetics, and poor reversibility make it difficult to be used for onboard hydrogen storage of fuel cell vehicles. A lot of researches on improving the dehydrogenation reaction thermodynamics and kinetics have been done, mainly including: additives or catalysts doping, nanoconfining Mg(BH)in nanoporous hosts, forming reactive hydrides systems, multi-cation/anion composites or other derivatives of Mg(BH). Some favorable results have been obtained. This review provides an overview of current research progress in magnesium borohydride, including: synthesis methods, crystal structures, decomposition behaviors, as well as emphasized performance improvements for hydrogen storage.

关键词： Magnesium borohydride Hydrogen storage Borohydrides Kinetics Thermodynamics

On the Hybrid Power Mean Involving the Two-Term Exponential Sums and Polynomial Character Sums

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Chinese Annals of Mathematics,Series B 2020年第4期41卷 547-558页

作者： Xingxing lv Xiaoxue LI School of Mathematics Northwest UniversityXi’an 710127China. Faculty of Science Xi’an Aeronautical UniversityXi’an 710077China.

The main purpose of this paper is using the analytic method and the properties of trigonometric sums and character sums to study the computational problem of one kind hybrid power mean involving two-term exponential s... 详细信息

关键词： The two-term exponential sums Kloosterman sums Dirichlet character of polynomials Hybrid power mean Identity

THEORETICAL ANALYSES ON DISCRETE FORMULAE OF DIRECTIONAL DIFFERENTIALS IN THE FINITE POINT METHOD

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Journal of Computational Mathematics 2022年第1期40卷 1-25页

作者： Guixia lv Longjun Shen Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsP.0.Box 8009-26Beijing 100088China

For the five-point discrete formulae of directional derivatives in the finite point method,overcoming the challenge resulted from scattered point sets and making full use of the explicit expressions and accuracy of the formulae,this paper obtains a number of theoretical results:(1)a concise expression with definite meaning of the complicated directional difference coefficient matrix is presented,which characterizes the correlation between coefficients and the connection between coefficients and scattered geometric characteristics;(2)various expressions of the discriminant function for the solvability of numerical differentials along with the estimation of its lower bound are given,which are the bases for selecting neighboring points and making analysis;(3)the estimations of combinatorial elements and of each element in the directional difference coefficient matrix are put out,which exclude the existence of ***,the theoretical analysis results are verified by numerical *** results of this paper have strong regularity,which lay the foundation for further research on the finite point method for solving partial differential equations.

关键词： Finite point method Finite difference Scattered point distribution Discrete directional differentials Theoretical analysis

Study on pathogenic genes of dwarfism disease by next-generation sequencing

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World Journal of Clinical Cases 2021年第7期9卷 1600-1609页

作者： lv-lv Yang Shi-Shan Liang Department of Pediatrics Quanzhou First HospitalQuanzhou 362000Fujian ProvinceChina

BACKGROUND There are many factors that lead to dwarfism,and the mechanism has not yet been ***-generation sequencing may identify candidate-related gene mutations,which may clarify the molecular *** To analyze genetic variation by using a constructed panel related to dwarfism by utilizing next-generation sequencing platform sequencing analysis to screen candidate-related gene *** Physical and laboratory characteristics,including clinical examination,growth hormone drug challenge test,serum insulin-like growth factor-1(IGF-1),IGF binding protein 3,other related tests,imaging examination,and chromosome karyotyping,were ***-generation sequencing was performed to analyze pathogenicity *** In the 39 dwarfism patients,10 had pathogenicity *** variation was found in the OBSL1,SLC26A2,PTPN11,COL27AI,HDAC6,CUL7,FGFR3,DYNC2H1,GH1,and ATP7B *** the 10 patients with pathogenicity variability,the related physical characteristics included double breast development and growth hormone deficiency,enuresis and indirect inguinal hernia on the left,two finger distance of 70.2 cm,head circumference of 49.2 cm,ischium/lower body length of 1.8 cm,weak limb muscles,and partial growth hormone *** 6 mo of growth hormone therapy,the concentrations of IGF-1 and IGF binding protein 3 increased from 215.2±170.3 to 285.0±166.0 and 3.9±1.4 to 4.2±1.1,*** OBSL1,SLC26A2,PTPN11,COL27AI,HDAC6,CUL7,FGFR3,DYNC2H1,GH1,and ATP7B genes may be related to the incidence of dwarfism,and more research needs to be performed to elucidate the mechanism.

关键词： Dwarfism Next-generation sequencing Pathogenicity variability Growth hormone Therapy Mechanism

Towards Safe Autonomous Driving:Decision Making with Observation‑Robust Reinforcement Learning

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Automotive Innovation 2023年第4期6卷 509-520页

作者： Xiangkun He Chen lv State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchunChina School of Mechanical and Aerospace Engineering Nanyang Technological University639798 NanyangSingapore

Most real-world situations involve unavoidable measurement noises or perception errors which result in unsafe decision making or even casualty in autonomous *** address these issues and further improve safety,automated driving is required to be capable of handling perception ***,this paper presents an observation-robust reinforcement learning against observational uncertainties to realize safe decision making for autonomous ***,an adversarial agent is trained online to generate optimal adversarial attacks on observations,which attempts to amplify the average variation distance on perturbed *** addition,an observation-robust actor-critic approach is developed to enable the agent to learn the optimal policies and ensure that the changes of the policies perturbed by optimal adversarial attacks remain within a certain ***,the safe decision making scheme is evaluated on a lane change task under complex highway traffic *** results show that the developed approach can ensure autonomous driving performance,as well as the policy robustness against adversarial attacks on observations.

关键词： Autonomous vehicle Robust reinforcement learning Safe decision making Adversarial attack

Error estimates of a finite element method for stochastic time-fractional evolution equations with fractional Brownian motion

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第1期13卷 192-213页

作者： Jingyun lv Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P.R.China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing 100049 P.R.China

The aim of this paper is to consider the convergence of the numerical methods for stochastic time-fractional evolution equations driven by fractional Brownian *** spatial and temporal regularity of the mild solution is *** numerical scheme approximates the problem in space by the Galerkin finite element method and in time by the backward Euler convolution quadrature formula,and the noise by the L *** strong convergence error estimates for both semi-discrete and fully discrete schemes are established.A numerical example is presented to verify our theoretical analysis.

关键词： Stochastic time-fractional evolution equations finite element method error estimates fractional Brownian motion

The Influence of Ultrasonic Frequency on the Properties of Ni-Co Coatings Prepared by Ultrasound-assisted Electrodeposition

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Acta Metallurgica Sinica(English Letters) 2013年第6期26卷 735-741页

作者： Minqi SHENG Chenkai lv Lan HONG Mingwang SHAO Kang WAN Fan lv School of Iron and Steel Soochow University Institute of Functional Nano & Soft Materials (FUNSOM) Soochow University

In this paper, Ni-Co coatings were electrodeposited onto carbon steel substrates with the aid of ultrasonic agitation. The coatings were analyzed by energy dispersive X-ray analysis （EDX）, X-ray diffraction analysis （XRD） and scanning electron microscopy （SEM）. The effects of the ultrasonic frequency on the roughness, hardness and corrosion resistance of the Ni-Co coatings were also investigated. The results indicated that the increase of the ultrasonic frequency from 20 to 120 kHz reduced the Ni content and the grain size of Ni-Co coatings. Moreover, the phase structure of the electrodeposited coatings was influenced by the ultrasonic frequency. Under 55 kHz ultrasonic agitation, the Ni-Co coating was single fcc phase and showed the finest roughness and the strongest corrosion resistance in 5 wt.% NaCl solution at the ambient temperature. Under ultrasonic agitation with frequency of 90 kHz, the coating was a mixture of fcc and hcp structure and showed the maximal hardness of about 420 HV. Therefore, ultrasonic agitation helped decrease the roughness, and enhance hardness and corrosion resistance of Ni-Co coatings.

关键词： Ni-Co alloys Coatings Electrodeposition Ultrasound Hardness Corrosion

Parameter identification for volumetric heat capacity and thermal conductivity in a quasi-linear thermodynamic system of sea ice

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International Journal of Biomathematics 2016年第3期9卷 211-225页

作者： Wei lv Department of MathematicsShanghai University Shanghai 200444 P. R. China

This paper is intended to determine physical parameters describing volumetric heat capacity and thermal conductivity of sea ice in u quasi-linear thermodynamic system using field observations. The quasi-linear thermodynamic system of sea ice with unknown physical parameters is described, and the existence and uniqueness of its solution is proved. Then the physical parameters are taken as control variable, temperature devi- ations as objective function, and a parameter identification model is established. The existence of its optimal solution is discussed. To solve the identification model, a new algorithm containing genetic algorithm, Hooke- Jeeves algorithm and semi-implicit finite difference scheme is constructed. The physical parameters are calculated using the obser- vations measured at Nella Fjord around Zhongshan Station, Antarctic in CHINARE 2006. For comparability and consistency with other works, a new internationM standard named TEOS-10 is used. To examine the validity of the identified results, another sim- ulation for temperature profiles in different measurement period is operated. Numerical results show that better simulations of temperature distribution are possible with the identified parameters than EC1993. Therefore not only the identified parameters can be applied in sea ice modeling, but also this study can enrich and supplement observations of sea ice.

关键词： Parameter identification quasi-linear thermodynamic system volumetricheat capacity thermal conductivity sea ice.

Recent advances in direct dehydrogenative biphenyl couplings

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Science China Chemistry 2017年第6期60卷 701-720页

作者： Fei lv Zhu-Jun Yao State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringCollaborative Innovation Center of Chemistry for Life ScieneesNanjing UniversityNanjing 210023China

Biphenyl moiety represents a unique structural motif of many natural and unnatural products with biological interests, and dehydrogenative couplings of two aryl C–H bonds under oxidative conditions is unambiguously the most efficient and direct preparation of these compounds. However, higher oxidation potential of benzene derivatives makes such oxidative couplings much more difficult than other arenes. Only very limited advances have been achieved on direct formation of the crucial C–C bond between two phenyl derivatives by dehydrogenative phenyl coupling in the last two decades. This article briefly summarized and commented a number of representative recent achievements in this attractive field, including homo-, cross-and intramolecular rearrangement and couplings, as well as their applications in organic synthesis.

关键词： biphenyl dehydrogenative coupling oxidation arene C–H bond activation