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Synthesis of new Squarains Used as Organic Electroluminescent Materials

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Chinese Chemical Letters 1997年第5期8卷 403-406页

作者： Liu, n Lu, ZY Xie, MG Jiang, q SICHUAn UnIV DEPT CHEMCHENGDU 610064PEOPLES R CHINA

Two types of eight kinds of new squarains were designed and synthesized. Their structures were elucidated by IR,nMR,MS and elementary analysis. Their luminescent properties were determined,which indicated that they ca... 详细信息

关键词： OC Cl

Synthesis and Properties of Layered Oxides LiCo_(1-x)ni_xO_2

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Journal of Materials Science & Technology 1997年第5期13卷 405-408页

作者： Lin, q Chen, n Ye, W Liu, RM Luo, JS GEn RES InST nOnFERROUS MET BEIJING 100088PEOPLES R CHINA

The mechanism of LiCo1－xnixO2(x=0, 0.5, 1) synthesis from carbonates or hydrates was studied by thermogravimetric analysis and X-ray diffraction to identify the medium and final products. The synthesis process from carbonates can be divided into two steps. Below 300℃cobalt carbonate and/or nickel carbonate decompose forming oxides. Over 300℃ Li2CO3 decomposes and reacts with Co and/or ni oxides gradually, as a result Co++ and/or ni++ areoxidized to Co+++ and/or ni+++, finally LiCo1-xnixO2 forms. The proportion of cobalt tonickel in the starting mixture and atmosphere during synthesis affects the structure of ***1-xnixO2(x≤0.5) can be synthesized in air or oxygen and characterized by solid solutionof LiCoO2 and LiniO2. LiniO2 can be obtained only from hydrates and in oxygen *** and LiCo0.5ni0.5O2 have higher first charge capacity than that of LiCoO2. Their discharge capacity reaches a level with that of LiCoO2 and has reasonable reversibility.

关键词： Lithium batteries

Magnetohydrodynamic flows tuning in a conduit with multiple channels under a magnetic field applied perpendicular to the plane of flow

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Journal of Hydrodynamics 2017年第2期29卷 332-343页

作者： Y.Luo C.n.Kim M.q.Zhu Department of Mechanical Engineering Graduate SchoolKyung Hee UniversityYong-inKorea Department of Mechanical Engineering College of EngineeringKyung Hee UniversityYong-inKorea

In this study, three-dimensional liquid-metal magnetohydrodynamic flows in a conduit with multiple channels under a uniform magnetic field are numerically investigated. The geometry of the conduit is of a four-parallel-channels system including one inflow channel and three outflow channels. The liquid-metal flows into the inflow channel, then turns through 180° in the transi- tion segment, finally flows into three different outflow channels. This kind of channel system can induce counter flow and co-flow, which is rarely investigated before though the conceptual designs of duct flow in the blanket have suggested this type of flow. A structured grid system is chosen after a series of mesh independence tests in the present study. The axial velocity in the side layer near the first partitioning wall, located between the inflow channel and the first outflow channel, is the highest with the lowest electric potential formed therein. The pressure almost linearly decreases in the main flow direction, except in the transition segment. Moreover, the pressure gradient in the first outflow channel is the largest among the three outflow channels. The interdependency of the current, fluid velocity, pressure, electric potential is examined in order to describe the electromagnetic characteristics of the liquid-metal flows.

关键词： Liquid-metal magnetohydrodynamics multiple channels

Electronic and thermoelectric properties of alkali metal-based perovskites CsYbF3 and RbYbF3

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Chinese Physics B 2020年第11期29卷 473-478页

作者： q Mahmood n A noor T Ghrib nessrin A Kattan Asif Mahmood Shahid M Ramay Basic and Applied Scientific Research Center Imam Abdulrahman Bin Faisal UniversityP.O.Box 198231441DammamSaudi Arabia Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 198231441DammamSaudi Arabia Department of Physics Riphah International UniversityLahorePakistan Department of Physics Faculty of ScienceTaibah UniversityMedinaSaudi Arabia Chemical Engineering Department College of EngineeringKing Saud UniversityRiyadhSaudi Arabia Physics and Astronomy Department College of ScienceKing Saud University RiyadhRiyadhSaudi Arabia

The electronic and thermoelectric properties of alkali metal-based fluorides CsYbF3 and RbYbF3 are studied by using Wien2k and BoltzTraP *** structural and thermodynamic stability of these materials are confirmed by tolerance factor(0.94 and 0.99 for RbYbF3 and CsYbF3)and negative formation *** optimized lattice constants and bulk moduli are consistent with the results reported in the *** reported band gap for RbYbF3 is 0.86 eV which decreases to 0.83 eV by the replacement of Cs with *** electrical and thermal conductivities along with Seebeck coefficients decrease with temperature rising from 0 K to 800 *** large values of thermoelectric parameters for positive chemical potentials show that the character is dominated by *** studied materials have figures of merit 0.82 and 0.81 at room temperature respectively,for RbYbF3 and CsYbF3 and increase with temperature ***,the materials under study may have potential application values in thermoelectric generators and refrigerators.

关键词： density functional theory thermodynamic stability electrical conductivity figure of merit

Oxygen and nitrogen Effects on MC Carbide in K465 nickel-Base Superalloy

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稀有金属材料与工程 2009年第A3期38卷 13-16页

作者： Wang L n Zheng q Sun X F Guan H R Hu Z q Institute of Metals Research Chinese Academy of Sciences Shenyang 110015 China

Effects of oxygen and nitrogen on MC carbide in nickel-base superalloy K465 were investigated, because neither of the two gas elements was found to decide MC carbide morphology monotonically. The morphology of MC carbide under alloy solidified in conventional investment casting condition was observed to transform from script-type to block-type with the total oxygen and nitrogen content (gas content) in samples rising up from 1.2×10-6 mol/g to 2.6×10-6 mol/g. The area fraction and composition of the MC carbide also varied with increase of gas content. However, the morphology of MC carbide kept to be script-type even when gas content was up to 3.4×10-6 mol/g in samples solidified with a much higher cooling rate. These results indicate that effects of gas content on formation of MC carbide can be observed in specimens solidified with low cooling rate, but such changes in MC carbide cannot be found when the cooling rate is high.

关键词：氧碳化物氮含量物理性能碳化物

Investigations of mechanical, electronic, and magnetic properties of non-magnetic MgTe and ferro-magnetic Mg_(0.75)T M_(0.25)Te (TM = Fe, Co, ni): An ab-initio calculation

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Chinese Physics B 2016年第4期25卷 303-313页

作者： Mahmood q Alay-e-Abbas S M Mahmood I Asif Mahmood noor n A Department of Physics University of the Punjab Quaid-e-Azam Campus Department of Physics Government College University Faisalabad Department of Physics University of Sargodha Centre for High Energy Physics University of the Punjab Quaid-e-Azam Campus College of Engineering Chemical Engineering Department King Saud University

The mechanical, electronic and magnetic properties of non-magnetic MgTe and ferro-magnetic （FM） Mgo.75 TM025 Te （TM = Fe, Co, ni） in the zinc-blende phase are studied by ab-initio calculations for the first time. We use the generalized gradient approximation functional for computing the structural stability, and mechanical properties, while the modified Becke and Johnson local （spin） density approximation （mBJLDA） is utilized for determining the electronic and magnetic properties. By comparing the energies of non-magnetic and FM calculations, we find that the compounds are stable in the FM phase, which is confirmed by their structural stabilities in terms of enthalpy of formation. Detailed descriptions of elastic properties of Mgo.75TMo.25Te alloys in the FM phase are also presented. For electronic properties, the spin- polarized electronic band structures and density of states are computed, showing that these compounds are direct bandgap materials with strong hybridizations of TM 3d states and Te p states. Further, the ferromagnetism is discussed in terms of the Zener free electron model, RKKY model and double exchange model. The charge density contours in the （110） plane are calculated to study bonding properties. The spin exchange splitting and crystal field splitting energies are also calculated. The distribution of electron spin density is employed in computing the magnetic moments appearing at the magnetic sites （Fe, Co, ni）, as well as at the non-magnetic sites （Mg, Te）. It is found that the p-d hybridization causes not only magnetic moments on the magnetic sites but also induces negligibly small magnetic moments at the non-magnetic sites.

关键词： FP-LAPW + lo elastic parameters spin polarized electronic properties magnetic properties

Stability analysis of a discrete biological model

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International Journal of Biomathematics 2016年第2期9卷 65-83页

作者： A. q. Khan M. n. qureshi Department of MathematicsUniversity of Azad Jammu and Kashmir Muzaffarabad 13100 Pakistan

In this paper, we investigate the equilibrium point, local and global behavior of the unique positive equilibrium point, and rate of convergence of positive solutions of following discrete biological model： Xn＋1=Xne^ln（α）（1-Yn）,Yn＋1=（γδ-1）Yn（1＋1/γδ-1-Yn/Xn）, where parameters α,γ,δ and the initial conditions Xo, ]Io are positive real numbers. Some numerical examples are given to verify theoretical results.

关键词： Discrete biological model local stability global character rate of convergence.

Experimental study of the effect of wear parameters on the wear behavior of A356 alloy/cow horn particulate composites

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Defence Technology（防务技术） 2018年第1期14卷 77-82页

作者： B.q.Ochieze C.C.nwobi-Okoye P.n.Atamuo Lafarge Africa Plc Mfamosing Plant Department of Mechanical Engineering Chukwuemeka Odumegwu Ojukwu University

Experimental study of the effect of wear parameters on the wear behaviour of A356 alloy reinforced with cow horn particles(CHp) produced by spark plasma sintering was investigated. Experiments were conducted based on the plan of experiments generated through Taguchi's(L9) technique. Tribometer was used for the wear test and Scanning electron microscope was used to analyse the worn scar of the samples. The results shows that, A356 alloy reinforced with CHp exhibited better dry sliding wear resistance than the unreinforced alloy. Wear rate decreased as the amount of CHp reinforcement increased in the matrix. It was found that, the optimum level of the factors with minimized the wear loss were obtained at: wt%CHp(20%), applied load(10 n), sliding velocity(3 m/s) and sliding distance(2000 m). It can be seen that the wear track of the sample are(D ? 0.81 and L = 42.85 mm) and(D ? 0.54 and L= 27.03 mm) for A356 alloy and composites at optimum condition respectively. The results showed that the addition of cow horn particles as reinforcing materials in A356 alloy composites increased the wear resistance of the composites greatly.

关键词： A356alloy Cow horn particles Microstructure Analysis of variance and wear behaviour

EVALUATIOn OF THE PROBABILITY DISTRIBUTIOn OF PITTInG CORROSIOn FATIGUE LIFE In AIRCRAFT MATERIALS

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Acta Mechanica Sinica 2003年第3期19卷 247-252页

作者：王清远 n.KAWAGOISHI q.Chen R.M.PIDAPARTI Dept.of Civil Eng.and Mechanics Sichuan UniversityChengdu 610065China

Corrosion and fatigue properties of aircraft materials are known to have a considerable scatter due to the random nature of materials,loading,and environmental conditions.A probabilistic approach for predicting the pitting corrosion fatigue life has been investigated which captures the effect of the interaction of the cyclic load and corrosive environment and all stages of the corrosion fatigue process (*** pit nucleation and growth,pit-crack transition,short- and long-crack propagation).The probabilistic model investigated considers the uncertainties in the initial pit size,corrosion pitting current,and material properties due to the scatter found in the experimental *** Carlo simulations were performed to define the failure probability *** cumulative distribution functions of fatigue life agreed reasonably well with the existing experimental data.

关键词： pitting corrosion fatigue probabilistic modeling fatigue life prediction