检索结果-南通市图书馆

Mssbauer spectra of MnFe_(2-2x)Al_(2x)O_4(0≤x≤0.4) ferrites

在线全文

学校读者我要写书评

暂无评论

journal of central South University 2010年第6期17卷 1129-1132页

作者： BATOO K M KUMAR S PRAKASh R ALIMUDDIN SONG j I chUNG h jEONG h KOO B h lee c G King Abdullah Institute for Nanotechnology King Saud UniversityRiyadh 11451Saudi Arabia School of Nano and Advanced Materials Engineering Changwon National UniversityChangwon 641773Korea Department of Mechanical Engineering Changwon National UniversityChangwon 641773Korea Department of Applied Physics Aligarh Muslim UniversityAligarh 202002India Department of Precision & Mechanical Engineering and BK21 Eco-Friendly heat & cooling Energy Mechanical Research Team Gyeongsang National U niversityTongyeong 650160Korea

The effect of non-magnetic Al^3＋ ion doping on the magnetic properties of MnFe2-2x Al2xO4 （0 ≤x≤ 0.4） spinel ferrites was studied using Moessbauer spectroscopy measurements at room temperature. From the Moessbauer study, it is observed that the ：esolved hyperfine sextets are due to the distribution of Fe ions on the two sublattices of the spinel ferrites. The value of the isomer shift obtained from the fitting of the Moessbauer spectra indicates that Fe ions are in ＋3 state. A paramagnetic doublet is observed at ：iegree of inversion x=0.4, superimposed on the hyperfine sextets, indicating that the super-exchange interaction A-B decreases due to ：he dilution of sublattice by Al^3＋ ions. The hyperfine magnetic field decreases at both interstitial sites of tetrahedral （A） and 3ctahedral （B） with the increase in Al concentration.

关键词： ferrites hyperfine interactions Moessbauer spectroscopy isomer shift

Microstructural Evolution in Directionally Solidified Ni-Base Superalloy IN792+hf

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2008年第1期24卷 110-114页

作者： S.M.Seo I.S.Kim j.h.lee c.Y.jo h.Miyahara K.Ogi high Temperature Materials Research Group KIMS Changwon641-010Korea Dept.of Metall.& Mater.Eng. changwon Univ. Changwon641-773Korea Dept.of Mater.Sci.& Eng. Kyushu Univ. Fukuoka819-0395Japan Oita National college of Technology Oita 870-0152Japan

Microstructural evolution during directional solidification （DS） of Ni-base superalloy IN792＋hf has been investigated with an emphasis on theγ′precipitates and Mc-type *** quantitative image analyses revealed that the increase in the solidification rate up to 100μm/s at constant thermal gradient of 178 K/cm resulted in a fine and uniform distribution ofγ′*** relationship between the as-castγ′size and cooling rate was also determined for DS IN792＋*** the mean time,the Mc carbide size was found to be dependent both on the solidification rate and the S/L interface morphology while the area fraction of Mc carbide was significantly influenced by the S/L interface morphology.

关键词： IN792 Mc corbide Gamma prime Solidification rate

Fault detection method with PcA and LDA and its application to induction motor

在线全文

学校读者我要写书评

暂无评论

journal of central South University 2010年第6期17卷 1238-1242页

作者： jUNG D Y lee S M 王洪梅 KIM j h lee S h Daeho Tech company Limited Department of Electronics Engineering Inha University School of Mechatronics Changwon National University

A feature extraction and fusion algorithm was constructed by combining principal component analysis(PcA) and linear discriminant analysis(LDA) to detect a fault state of the induction *** yielding a feature vector with PcA and LDA from current signal that was measured by an experiment,the reference data were used to produce matching *** a diagnostic step,two matching values that were obtained by PcA and LDA,respectively,were combined by probability model,and a faulted signal was finally *** the proposed diagnosis algorithm brings only merits of PcA and LDA into relief,it shows excellent performance under the noisy *** simulation was executed under various noisy conditions in order to demonstrate the suitability of the proposed algorithm and showed more excellent performance than the case just using conventional PcA or LDA.

关键词： principal component analysis (PcA) linear discriminant analysis (LDA) induction motor fault diagnosis fusionalgorithm

Mathematical modeling and simulations of stress mitigation by coating polycrystalline particles in lithium-ion batteries

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： N.IQBAL j.chOI S.F.ShAh c.lee S.lee Department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyco_(z)O_(2)(x≥0.8)(NMc)particles with poly(3,4-ethylenedioxythiophene)(PEDOT).The simulation results show that the coating of primary NMc particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic conductivity,and larger thickness of the coating layer improve the stress *** paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMc active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation Ni-rich LiNixMnyco_(z)O_(2)(x>0.8)(NMc)

FTIR Studies on NO Adsorption on [co+Mg(Sr)] /ZSM-5

在线全文

学校读者我要写书评

暂无评论

chemical Research in chinese Universities 2002年第4期18卷 389-392页

作者： lee c. W. chONG P. j. KRIcT Taejon 305-606 KoreaKRICT Taejon 305-606 Korea

The adsorption of NO on /ZSM-5 zeolites with different contents was studied by means of FTIR spectroscopy. The dominant NO species adsorbed on /ZSM-5 was found to be in a dinitrosyl form, as demonstrated by the IR bands at 1 813 and 1 896 cm -1. NO was adsorbed in a mononitrosyl form as shown in the region of 1 937-1 939 cm -1 as a minor species. Samples /ZSM-5 showed a new band near 1 858 cm -1(w) attributable to the species of co_3O_4-NO. It was found that zeolite /ZSM-5 exhibits superior performance characteristics for ScR of NO molecules, and is promising as a useful catalyst. The typical catalyst /ZSM-5 for ScR resulted from the collaboration of the metal alkalinity and the ionic radius of the metal(such as Mg or Sr).

关键词： Infrared spectroscopy Nitric oxide Adsorption Mononitrosyl Dinitrosyl cobalt oxide

MODIFIcATION OF SODIUM SALT OF PARTIALLY cARBOXYMEThYLATED TAMARIND KERNEL POWDER ThROUGh GRAFTING WITh AcRYLONITRILE: SYNThESIS, chARAcTERIZATION AND SWELLING BEhAVIOR

在线全文

学校读者我要写书评

暂无评论

chinese journal of Polymer Science 2013年第12期31卷 1670-1684页

作者： j.h.Trivedi j.R.jivani K.h.Patel h.c.Trivedi P.G.Dept.of chemistry Sardar Patel UniversityVallabh Vidyanagar Amneal Phamaceuticals

A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PcMTKP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （cAN） as a redox initiator in an aqueous medium. The optimum reaction conditions for affording maximum percentage of grafting were established by successively varying reaction conditions such as concentrations of nitric acid, cAN, monomer （AN） as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields was discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer （Na-PcMTKP-g-PAN, percentage of grafting G = 413.76% and percentage of grafting efficiency GE = 96.48%） sample synthesized under the established optimized reaction conditions was hydrolyzed by 0.7 mol-L l NaOh solution at 90-95 ℃ to yield the superabsorbent hydrogel, h-Na-PcMTKP-g-PAN. The swelling behavior of the hydrogel was studied by carrying out its absorbency measurements in low conductivity water, 0.15 mol·L^-1 salt （Nacl, cacl2 and Alcl3） solutions and simulated urine （SU） solution at different timings. FTIR, TGA and SEM techniques were used to characterize the products.

关键词： Sodium salt of partially carboxymethylated tamarind kernel powder Acrylonitrile Graft copolymerization Superabsorbent hydrogels Swelling behavior.

Effect of interlayer addition on microstructure and mechanical properties of NiTi/stainless steel joint by electron beam welding

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2021年第2期61卷 16-24页

作者： h.Niu h.c.jiang M.j.Zhao L.j.Rong cAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of ScienceShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei230026China

NiTi/Stainless Steel(SS) sheets have been welded via a vacuum electron beam welding process, with three methods(offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding Fe Ni interlayer), to promote mechanical properties of the Ni Ti/SS joints. The joints with different interlayers are all fractured in the weld zone near the Ni Ti side, which is attributed to the enrichment of intermetallic compounds including Fe2 Ti and Ni3 Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding Fe Ni interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. compared with the brittle laves phase Fe2 Ti, Ni3 Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3 Ti and Fe2 Ti will be formed when the Fe Ni alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 MPa.

关键词： NiTi Stainless steel Electron beam welding Interlayer Mechanical property

Development of mathematical model with a genetic algorithm for automatic arc welding process

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2010年第3期23卷 230-240页

作者： D.T.Thao I.S.Kim j.W.jeong j.h.lee j.Y.Shim h.h.Kim Department of Mechanical Engineering Mokpo National University

This paper is to represent new algorithms to predict process parameters on top-bead width in robotic gas metal arc（GMA） welding *** models have been developed：linear, curvilinear and intelligent model based on full factorial design with two *** analysis was employed for optimization of the coefficients of linear and curvilinear models, while genetic algorithm（GA） was utilized to estimate the coefficients of an intelligent *** only the fitting of these models were checked and compared by using a variance test（ANOVA）, but also the prediction on top-bead width using the developed models were carried out based on the additional *** developed models were employed to investigate the characteristic between process parameters and top-bead *** solutions and graphical representation showed that the intelligent model developed can be employed for prediction of bead geometry in GMA welding process.

关键词： Top-bead width Genetic algorithm Multiple regression Robotic arc welding GMA welding

在线全文

学校读者我要写书评

暂无评论

journal of central South University 2009年第5期16卷 789-793页

作者： KIM j h lee S h 王洪梅 School of Mechatronics Changwon National University 9 Sarim-dong Changwon Gyeongnam 641-773 Korea

Fault detection technique is introduced with similarity measure. The characteristics of conventional similarity measure based on fuzzy number are discussed. With the help of distance measure, similarity measure is constructed explicitly. The designed distance-based similarity measure is applicable to general fuzzy membership functions including non-convex fuzzy membership function, whereas fuzzy number-based similarity measure has limitation to calculate the similarity of general fuzzy membership functions. The applicability of the proposed similarity measure to general fuzzy membership structures is proven by identifying the definition. To decide fault detection of flight system, the experimental data （pitching moment coefficients and lift coefficients） are transformed into fuzzy membership functions. Distance-based similarity measure is applied to the obtained fuzzy membership functions, and similarity computation and analysis are obtained with the fault and normal operation coefficients.

关键词： similarity measure fuzzy number, distance non-convex membership function