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Sequencing and analysis of the complete mitochondrial DNA of Russell's snapper (***)

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Progress in Natural Science:Materials International 2008年第10期18卷 1233-1238页

作者： Yusong Guo~(a,1) Zhongduo Wang~(a,b,1) Chuwu liu~(a,*) Yun liu~b ~a Fisheries College,Guangdong Ocean University,Zhanjiang 524025,China ~b College of Life Science,Hunan Normal University,Changsha 410081,China Fisheries College Guangdong Ocean University Zhanjiang 524025 China College of Life Science Hunan Normal University Changsha 410081 China

The entire mitochondrial DNA sequence (mitogenome) of Russell’s snapper (Lutjanus russellii) was determined using long PCR and primer-walking methodology,representing the first complete mitogenome accessioned for Lutjanid fishes (16,505 bp,Genbank Acces- sion ***514208).The mitogenome was similar in gene composition and order to those of other vertebrates,having 37 structural genes,i.e.,two ribosomal RNAs,22 transfer RNAs,and 13 protein-coding *** analyses based on the mtDNA sequence of Russell’s snapper supported a close relationship between Lutjaninae and Caesioninae,consistent with taxonomic hypotheses based on *** studies utilizing mitogenomes are needed to resolve high-level relationships among snappers.

关键词： Lutjanus russellii Mitochondrial DNA Mitogenome Complete mtDNA sequence Long PCR

Preparation and characterization of nanostructured Al_2O_3-13wt.%TiO_2 ceramic coatings by plasma spraying

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Rare Metals 2009年第5期28卷 465-470页

作者： WANG Dongsheng TIAN Zongjun SHEN Lida liu Zhidong HUANG Yinhui Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Nanostructured and conventional Al2O3-13wt.%TiO2 ceramic coatings were prepared by plasma spraying with nanostructured agglomerated and conventional powders, respectively. The microstructure and microhardness of the coatings were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and microhardness measurement. Meanwhile, the friction and wear behaviors were analyzed and compared using a ball-on-disk tribometer. The results show that the conventional coating has lamellar stacking characteristic and has some pores. However, the nanostructured coating shows a bimodal microstructure, which is composed of both fully melted regions and partially melted regions. According to the microstructural difference, the partially melted regions can be divided into liquid-phase sintered regions （a three-dimensional net or skeleton-like structure： Al2O3-rich submicron particles embedded in the TiO2-rich matrix） and solid-phase sintered regions （remained nanoparticles）. The microstructural characteristics of the liquid-phase sintered region are formed due to the selective melting of TiO2 nanoparticles during plasma spraying. On the other hand, the TiO2 and Al2O3 nanoparticles of the solid-phase sintered regions are all unmelted during plasma spraying. Due to the existence of nanostructured microstructures, the nanostructured coating has a higher microhardness, a lower friction coefficient, and a better wear resistance than the conventional coating.

关键词： surface coating nanostructured coating plasma spraying microstructure microhardness wear resistance

Recent advances in fermentative biohydrogen production

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Progress in Natural Science:Materials International 2008年第3期18卷 253-258页

作者： Xuemei liu a,b, Nanqi Ren a, Funan Song b, Chuanping Yang b, Aijie Wang a a Harbin Institute of Technology, Harbin 150010, China b Northeast Forestry University, Harbin 150040, China Harbin Institute of Technology Harbin 150010 China Northeast Forestry University Harbin 150040 China

Hydrogen energy, as a kind of clean energy with great potential, has been a hotspot for study worldwide. based on the recent research on biohydrogen production, this paper gives a brief review on the following aspects: fermentative hydrogen production process and the engineering control statagy, key factors affecting the effciency of hydrogen production, such as substrates, cysteine, metal ions, anaerobic fermentation terminal products, and formic acid and ammonia. Moreover, anaerobic fermentative hydrogen-producing strain and reg- ulation and control of enzyme gene in fermentative hydrogen production are also discussed. Finally, the prospect of anaerobic fermen- tative biohydrogen production is proposed in three study areas, namely developing new techniques for breeding hydrogen-producing bacteria, exploitations of more strains and gene resources, and intensifying the application of microbial molecular breeding in hydrogen production.

关键词： Fermentation biohydrogen production Regulation and control Novel strains

Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

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Journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.liu S.J.liu b.Wang W.b.Sun X.J.liu Z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),W-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

New exact solutions for free vibrations of rectangular thin plates by symplectic dual method

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Acta Mechanica Sinica 2009年第2期25卷 265-270页

作者： Y. Xing b. liu The Solid Mechanics Research Center, beihang University, 100083 beijing, China The Solid Mechanics Research Center Beihang University Beijing China

The separation of variables is employed to solve Hamiltonian dual form of eigenvalue problem for transverse free vibrations of thin plates, and formulation of the natural mode in closed form is performed. The closed-form natural mode satisfies the governing equation of the eigenvalue problem of thin plate exactly and is applicable for any types of boundary conditions. With all combinations of simplysupported （S） and clamped （C） boundary conditions applied to the natural mode, the mode shapes are obtained uniquely and two eigenvalue equations are derived with respect to two spatial coordinates, with the aid of which the normal modes and frequencies are solved exactly. It was believed that the exact eigensolutions for cases SSCC, SCCC and CCCC were unable to be obtained, however, they are successfully found in this paper. Comparisons between the present results and the FEM results validate the present exact solutions, which can thus be taken as the benchmark for verifying different approximate approaches.

关键词： Classical theory of thin plate Frequency Free vibrations Symplectic dual method Exact solution

Exact solution and transient behavior for torsional vibration of functionally graded finite hollow cylinders

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Acta Mechanica Sinica 2009年第4期25卷 555-563页

作者： H. M. Wang C. b. liu H. J. Ding Department of Mechanics Zhejiang University Department of Civil Engineering Zhejiang University

Exact solutions are obtained for transient torsio- nal responses of a finitely long, functionally graded hollow cylinder under three different end conditions, i.e. free-free, free-fixed and fixed-fixed. The cylinder with its external surface fixed is subjected to a dynamic shearing stress at the internal surface. The material properties are assumed to vary in the radial direction in a power law form, while keep invariant in the axial direction. With expansion in the axial direction in terms of trigonometric series, the governing equations for the unknown functions about the radial coordinate r and time t are deduced. by applying the variable substitution technique, the superposition method and the separation of variables consecutively, series-form solutions of the equations are obtained. Natural frequencies and the transient torsional responses are finally discussed for a functionally graded finite hollow cylinder.

关键词： Exact solution Functionally graded material Finite hollow cylinder Transient torsional vibration

Thermal shock fatigue behavior of TiC/Al_2O_3 composite ceramics

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Rare Metals 2008年第3期27卷 308-314页

作者： SI Tingzhi liu Ning ZHANG Qing＇ an YOU Xianqing School of Materials Science and Engineering Anhui University of Technolog3 Ma ＇anshan 243002 China School of Materials Science and Engineering Hefei University＇ of Technology Hefei 230009 China

The thermal shock fatigue behaviors of pure hot-pressed alumina and 30 wt.% TiC/Al2O3 composites were studied. The effect of TiC and Al2O3 starting particle size on the mechanical properties of the composites was discussed. Indentation-quench test was conducted to evaluate the effect of thermal fatigue temperature difference （ΔT） and number of thermal cycles （Ⅳ） on fatigue crack growth （Δa）. The mechanical properties and thermal fatigue resistance of TiC/Al203 composites are remarkably improved by the addition of TiC. The thermal shock fatigue of monolithic alumina and TiC/Al2O3 composites is due to a ＂true＂ cycling effect （thermal fatigue）. Crack deflection and bridging are the predominant reasons for the improvement of thermal shock fatigue resistance of the composites.

关键词： ceramic matrix composites TiC/Al2O3 composites thermal shock fatigue fatigue behavior fatigue resistance

PREPARATION AND XRD STUDY OF LITHIUM DEFICIENT Lib COMPOUND

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 667-671页

作者： Z.J.liu b.Y.Huang Z.Y.Li StateKeyLaboratoryforPowderMetallurgy CentralSouthUniversityChangsha410083China

The Lib compounds in lithium deficient state were prepared by three methods and its crystal structure was investigated by using XRD. It is found that the lattice constant c of the compound will increase step by step with decreasing Li content from 0.2796nm of the normal Lib to 0.2886, 0.2981 and 0.3118nm of the lithium deficient Lib. The change of the lattice constant is reversible.

关键词： Lib compound crystal structure electrode materials X-ray diffraction

Magnetic reversal and magnetic memory effect in melt-spun Pr_2Fe_(14)b/α-Fe nanocomposite ribbons

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Journal of Rare Earths 2015年第12期33卷 1303-1309页

作者：韩广兵苏浩高汝伟于淑云康仕寿朱明刚李卫 X.b.liu School of Physics Shandong University Division of Functional Materials Central Iron & Steel Research Institute Department of Physics University of Texas at Arlington

The influence of CoCr addition on the microstructure and magnetic properties was investigated in nanocomposite Pr2Fel4b/a-Fe alloys prepared by melt spinning. It was shown that the magnetic properties of Pr2Fel4b/ct-Fe nanocomposite were im- proved by an addition of 10 at.% CoCr, in particular, coercivity （Hc） from 4.9 up to 5.3 kOe, maximum energy product （（bH）max） from 10.6 up to 13.9 MGOe, and remanence （Mr） from 94.2 up to 98.4 emu/g. The field dependencies of the reversible and irreversible magnetization components were derived from the recoil loops. Combining with the initial magnetization curves, the results indi- cated that the pinning of domain walls at the grain boundaries dominated the magnetization reversal in Pr2Fe14b/ct-Fe nanocomposite alloys. The magnetic memory effect was studied by measuring the magnetic moment relaxation at a cycle negative magnetic field with time interval of 600 s. The exchange-spring magnets with magnetic memory effect have a high potential for high density magnetic recording.

关键词： magnetization reversal exchange coupling magnetic memory effect nanocomposite alloys coercivity rare earths