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FoRMATIoN oF GRADIENT coATING oF Fe-BASED ALLoY WITH RARE EARTHS BY PLASMA SURFAcING

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 713-718页

作者： L.J.Shang A.q.Sun J.F.chen c.M.Zhang q.K.cai collegeofMaterialsScienceandEngineering ShenyangPolytechnicUniversityShenyang110023China SchoolofMaterialsandMetallurgy NortheasternUniversityShenyang110004China

A gradient coating of Fe-based alloy was manufactured with rare earths (RE) by plasma surfacing on q235 steel substrate. The coatings were studied by using X-ray diffraction(XRD), scanning electron microscope(SEM), differential thermal analyzer(DTA), and electron probe micro-analyzer (EPMA). The results show that the phases of the two kinds of coatings(with and without RE) both include α-Fe, Fe7c3, Fe3c, cr2B, Fe2B and FeB. The microstructure of F314 coating is mainly hypereutectic, the pro-phases cr7c3 and cr2B are loose, crassi, spiculate and contain microcracks. The brittleness of the coating is high, and the average hardness is 787 HV. When 0.8wt% RE was added into the F314 alloy, the microstructure varied from hypoeutectic to hypereutectic continuously, The hardness appears as gradient distribution with the highest value of 773 HV, meanwhile, the brittleness decreases significantly. The formation of gradient structure depends on the fallowing factors: (i) the conversion of RE. The addition of RE lowers the elements point and Fe-c eutectic temperature, thus the base metal melting acutely. (ii) the heating of plasma arc. Graded temperature results in directional solidification, thus the gradient structure forms easily. The main reasons for the hardness decrease with RE addition in the alloy are the ratio of hard phase lowering and the hardness of the hard phase decreasing.

关键词： rare earth plasma surfacing Fe-base alloy microstructure graded coating

Using SPoT 5 fusion-ready imagery to detect chinese tamarisk(saltcedar)with mathematical morphological method

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International Journal of Digital Earth 2014年第3期7卷 217-228页

作者： q.S.Liu G.H.Liu c.Huang c.J.Xie State Key Laboratory of Resources and Environmental Information System Institute of Geographic Science and Natural Resources ResearchChinese Academy of SciencesBeijingChina

chinese tamarisk(saltcedar)is a deciduous shrub that occurs widely across the Yellow River Delta in *** spatial structure of chinese tamarisk is believed to have an influence on the landscape and habitats of rare *** this study,first,chinese tamarisk is detected using canny edge detector and mathematical morphological operators based on SPoT 5 fusion-ready *** the numbers,areas,locations,and patch spacing of chinese tamarisk patches are *** experiments show that the detection accuracy of chinese tamarisk patches is about 93.4%after the disconnection of connected *** distribution orientation of about 70%of the patches is approximately *** 91%of the minimum distances among the patches are between 12.5 and 57.5 *** rose graph indicates that the main azimuth between patches is north--northwest,and the second is northeast and *** present study indicates that the integrating canny edge detector with the algorithms for extracting circular and elliptical objects based on mathematical morphology is simple and effective for detecting chinese tamarisk patches and is easy to identify the spatial structure of chinese tamarisk patches,which reduces the time and labor for the visual interpretation of chinese tamarisk patches.

关键词： SPoT 5 chinese tamarisk spatial structure mathematical morphology patch

Finite Element Simulation on Thermal Fatigue of a Turbine Blade with Thermal Barrier coatings

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Journal of Materials Science & Technology 2014年第4期30卷 371-380页

作者： L.Yang q.X.Liu Y.c.Zhou W.G.Mao c.Lu Key Laboratory of Low Dimensional Materials & Application Technology(Ministry of Education) Xiangtan University Faculty of Materials Optoelectronic & PhysicsXiangtan University Department of Mechanical Engineering Curtin University

In this paper, a finite element model was developed for a turbine blade with thermal barrier coatings to investigate its failure behavior under cyclic thermal loading. Based on temperature and stress fields obtained from finite element simulations, dangerous regions in ceramic coating were determined in terms of the maximum principal stress criterion. The results show that damage preferentially occurs in the chamfer and rabbet of a turbine blade with thermal barrier coatings and its thermal fatigue life decreases with the increase of thermal stress induced by high service temperature.

关键词： Turbine blade Thermal barrier coatings Finite element model Thermal fatigue Life prediction

MoDIFIcATIoN oF SURFAcE MEcHANIcAL PRoPERTIES oF PoLYcARBoNATE BY B^+ AND o^+ IoNS IMPLANTATIoN

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 33-38页

作者： S.D. Yao c. Sun S.q. Zhou c.c. Sun Y.H. Lu L. Huang A. Vantomme q. Zhao G. Langouche Sch. of Phys. Peking Univ. Beijing 100871 China

By implanting B+ and o+ ions respectively into polycarbonate (Pc) plates, the surface mechanical properties of Pc have been improved. Measurement by Nano Indenter II showed that the hardness of samples increased 7-25 times than that before implantation; and the modulus of elasticity raised 2-5 times. The wear-resistance was tested by ball crusher; the width and depth of the wear-streak decreased by 1/3-1/2 or even more. The structure, deformation and appearance were analyzed by using Micro-FTIR Spectra, EScA method and the steps instrument. These analyses showed that the structure of Pc had been modified: a series of new cross-linking yielded, it depends on the Linear Energy Transition (LET) of implanted ions in the high polymer compounds.

关键词： polycarbonate ion implantation surface modification

EFFEcT oF NANocRYSTALLINE AND TWIN BoUNDARIES oN coRRoSIoN BEHAVIoR oF 316L STAINLESS STEEL USING SMAT

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 183-189页

作者： A.q. Lü Y. Zhang Y. Li G. Liu q.H. Zang c.M. Liu School of Materials and Metallurgy Northeastern University Shenyang 110004 China Jiuquan Iron ＆ Steel （Group） Go. Ltd Jiayuguan 735100 China State Key Laboratory for corrosion and Protection of Metals Institute of Metal Research The Chinese Academy of Sciences Shenyang 110015 China Shenyang National Laboratory for Materials Science Institute of Metal Research The Chinese Academy of Science Shenyang 110016 China

By means of surface mechanical attrition treatment （ SMAT）, the groin size with a diameter of aboat 60hm formed at about 20μm depth and numerous mechanical twins at about 50μm depth from the treated surface were synthesized in 316L stainless steel because of the different distributions of strain and strain rate along depth orientation. For instance the maximum strain rate reached 10^3-10^4s^-1 on the top surface. The relationship between the microsturcture and the corrosion property was studied in 0.05M H2So4＋ 0.25M Na2So4 aqueous solution, and the results show an extreme improvement of corrosion resistance owing to the appearance of twin boundaries and the obvious reduction in corrosion resistance attributed to the presence of nanocrystaline boundaries.

关键词： surface mechanical attrition treatment 316L stainless steel corrosion property twin boundary nanocrystaline boundary

Magnetism,optical,and thermoelectric response of cdFe_2o_4by using DFT scheme

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chinese Physics B 2018年第3期27卷 376-383页

作者： q Mahmood M Yaseen K c Bhamu Asif Mahmood Y Javed Shahid M Ramay Materials Growth and Simulation Laboratory Department of PhysicsUniversity of the Punjab Department of Physics University of AgricultureFaisalabad Department of Physics Goa University chemical Engineering Department College of Engineering King Saud University Physics and Astronomy Department College of Science King Saud University

comparative analysis of electronic, magnetic, optical, and thermoelectric properties of cdFe2o4, calculated by em- ploying PBEsol ＋ mBJ has been done. The PBEsol reveals metallic nature, while TB-mBJ illustrates ferromagnetic semiconducting behavior. The reasons behind the origin of ferromagnetism are explored by observing the exchange, crystal field, and John-Teller energies. The optical nature is investigated by analyzing dielectric constants, refraction, absorption coefficient, reflectivity, and optical conductivity. Finally, thermoelectric properties are elaborated by describing the electri- cal and thermal conductivities, Seebeck coefficient, and power factor. The strong absorption for the visible energy and high power factor suggest cdFe2o4 as the potential candidate for renewable energy applications.

关键词： frustrated magnetism density functional theory John-Teller distortion Hund's rule

Mathematical modeling and numerical computation of the effective interfacial conditions for Stokes flow on an arbitrarily rough solid surface

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 721-746页

作者： A.T.TRAN H.LE qUANG q.c.HE D.H.NGUYEN Research and Application center for Technology in civil Engineering University of Transport and CommunicationsHanoi 10000Vietnam Laboratoire Modelisation et Simulation Multi-Echelle Unite Mixte de Recherche 8208Centre National de la Recherche ScientifiqueUniversite Gustave EiffelMarne-la-Vallee F-77454France School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China

The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid *** distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily *** main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip *** solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly *** results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the *** comparison shows that the two proposed methods are particularly efficient and accurate.

关键词： effective slip length method of fundamental solution(MFS) boundary element method(BEM) Stokeslet micro-channel fluid/solid interface

cLE peptide-mediated signaling in shoot and vascular meristem development

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Frontiers in Biology 2017年第6期12卷 406-420页

作者： Thai q. Dao Jennifer c. Fletcher Plant Gene Expression center United States Department of Agriculture-Agricultural Research Service Albany CA 9471 O USA Department of Plant and Microbial Biology University of California Berkeley Berkeley CA 94720 USA

Multicellular organisms rely on the transmission of information between cells to coordinate various biological processes during growth and development. Plants, like animals, utilize small peptide ligands as signaling molecules to transmit information between cells. These polypeptides typically act as extracellular messengers that are perceived by membrane-bound receptors, which then transduce the signal into the recipient cell to modify downstream gene transcription. The cLAVATA3/EMBRYo SURRoUNDING REGIoN-RELATED (cLE) proteins represent one of the largest and best understood families of small polypeptides in plants. Members of the cLE family play critical roles in mediating cell fate decisions during plant development, particularly within the unique meristem structures that contain stem cell reservoirs acting as sources of cells for continuous organ formation. Here we review the roles of cLE family members in regulating the activity of the shoot apical meristems that generate the aerial parts of the plants, and of the vascular meristems that produce the sugar- and water-conducting tissues. A systematic literature search was performed using the Google Scholar and PubMed search engines. The keywords “cLE”, “cLV3”, “TDIF”, “meristem”, and “plant stem cells” were used as search terms. The 95 retrieved articles, dating from 1992, were organized by topic and their key findings incorporated into the text. We summarize our current understanding of how the cLE peptide cLV3 orchestrates the activity of shoot apical meristems, describing its expression, processing and movement, as well as its intracellular signal transduction pathways, key target genes and downstream gene regulatory networks. We also discuss the roles of cLE peptide signaling in the vascular meristems to promote procambial cell proliferation and suppress xylem differentiation. Signaling pathways mediated by cLE peptides are critical for stem cell maintenance and differentiation in shoot apical and vascular me

关键词： cLE cLV3 TDIF WUS stem cells procambium

SYNTHESIS AND IDENTIFIcATIoN oF coNDUcTING PoLYANILINE DoPED WITH RARE EARTH cHLoRIDE

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 872-876页

作者： Yang, c.M. Zhang, q.R. Fang, Z. central South Univ of Technology Changsha China

Polyaniline doped with rare earth chloride was synthesized in organic solvent and identified by elemental analysis and infrared spectroscopy. The experimental results show that there exists both doping and complexation at the same time in the resulting product. When pH4. Moreover, polyaniline doped with rare earth chloride exhibits better thermal stability than that doped with hydrochloric acid.

关键词： chlorine compounds composition conductive materials Electric conductivity organic polymers Rare earth compounds Synthesis (chemical)