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Solving nonlinear differential equations of Vanderpol, Rayleigh and duffing by AGM

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Frontiers of Mechanical Engineering 2014年第2期9卷 177-190页

作者： M. R. AKBARI d. d. GANJI A. MAJIdIAN A. R. AHMAdI department of Civil Engineering and Chemical Engineering University of Tehran Yehran Iran department of Mechanical Engineering Babol University of Technology Babol Iran department of Mechanical Engineering Sari Branch Islamic Azad University Sari Iran

In the present paper, three complicated non- linear differential equations in the field of vibration, which are Vanderpol, Rayleigh and duffing equations, have been analyzed and solved completely by Algebraic Method （AGM）. Investigating this kind of equations is a very hard task to do and the obtained solution is not accurate and reliable. this issue will be emerged after comparing the achieved solutions by numerical method （Runge-Kutte 4th）. Based on the comparisons which have been made between the gained solutions by AGM and numerical method, it is possible to indicate that AGM can be successfully applied for various differential equations particularly for difficult ones. the results reveal that this method is not only very effective and simple, but also reliable, and can be applied for other complicated nonlinear problems.

关键词： Algebraic Method (AGM) Angular Frequency Vanderpol Rayleigh duffing

Brake Fault diagnosis through Machine Learning Approaches–A Review

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Structural durability & Health Monitoring 2017年第1期11卷 41-61页

作者： t.M.Alamelu Manghai R.Jegadeeshwaran V.Sugumaran School of Mechanical and Building Sciences VIT University Chennai CampusChennaiTamil NaduIndia-600127

diagnosis is the recognition of the nature and cause of a certain *** is generally used to determine cause and effect of a problem. Machine fault diagnosis isa field of finding faults arising in machines. to identify the most probable faults leadingto failure, many methods are used for data collection, including vibration monitoring,thermal imaging, oil particle analysis, etc. then these data are processed using methodslike spectral analysis, wavelet analysis, wavelet transform, short-term Fourier transform,high-resolution spectral analysis, waveform analysis, etc. the results of this analysis areused in a root cause failure analysis in order to determine the original cause of the *** paper presents a brief review about one such application known as machine learningfor the brake fault diagnosis problems.

关键词： Vibration analysis machine learning feature extraction feature selection feature classification brake fault diagnosis

Guinea pig model of tuberculosis

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Asian Pacific Journal of tropical Medicine 2009年第2期2卷 76-80页

作者： Pushpa Gupta U.d.Gupta Experimental Animal Facility National JALMA Institute for Leprosy & Other Mycobacterial DiseasesTajganjAgra 282001India

Animal models are being developed for testing different vaccine candidates as well as testing of new antitubercular since a long ***,guinea pigs and rabbits are animals which are frequently *** each model has got its merits as well as demerits and each of them differ from human tuberculosis in one aspect or the other but none of the model completely mimics the human *** of the different animal species, guinea pig model is one of the better models as it is very sensitive to *** infection but it has certain limitations like paucity of immunological ***,it is the best model for tuberculosis research.

关键词： Vaccines Animal Models tuberculosis Guinea pig

In-port-plug transmission line design of the ItER plasma position reflectometer

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Plasma Science and technology 2020年第6期22卷 15-20页

作者： J MARtÍNEZ-FERNÁNdEZ ÁCAPPA A SIMONEttO t EStRAdA E dE LA LUNA E J BLANCO Laboratorio Nacional de Fusión.CIEMAt Avda Complutense 40.Madrid 28040Spain CNR-IStP via Cozzi 5320125 MilanoItaly

this work describes the microwave design of the transmission line housed in the in-port-plug region of the ItER plasma position reflectometer(PPR).the design of the components of the inport-plug reflectometers(located in equatorial port-plug 10(EPP10) and in upper-port-plug 01(UPP01)) is *** a 3 d ray tracing code, the spatial position and optimum orientation angles of each set of emission and detection antennas were determined.A feasible path was then created from the obtained antenna positions and orientations to the primary vacuum *** tall waveguides were chosen to reduce ohmic *** to space constraints in the ItER crowded environment, bends in oversized waveguides were unavoidable, and thus mode conversion was *** keep mode conversion losses at bay, hyperbolic secant curvature bends had to be used whenever ***, E-plane bends in tall waveguides proved to be especially critical, making it necessary to employ other approaches when higher bending angles were *** conversion results were obtained by evaluating the mode coupling *** losses have also been computed and their results compared with commercial simulators, obtaining a perfect agreement.

关键词： reflectometry microwave technology ItER diagnostic

Effect of grain size on iron-boride nanoglasses

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Journal of Materials Science & technology 2023年第10期141卷 116-123页

作者： Melody M.Wang Mehrdad t.Kiani Abhinav Parakh Yue Jiang X.Wendy Gu department of Materials Science and Engineering Stanford UniversityStanfordCA 94305USA department of Mechanical Engineering Stanford UniversityStanfordCA 94305USA

Metallic nanoglasses are made of amorphous grains that are separated by lower-density amorphous boundaries,which have been proposed to enhance plasticity through the deflection of cracks and shear bands at *** has been difficult to experimentally control grain size and interfacial structure to understand their roles in plastic ***,we fabricate bulk nanoglasses via compaction and sintering of colloidally synthesized amorphous iron-boride *** nanoglasses have amor-phous grains with diameters from 116 nm to 576 nm and were tested using nanoindentation and mi-cropillar *** nanoglass with a grain size of 576 nm shows the highest elastic modulus and hardness of 101 GPa and 7.4 GPa,*** electron microscopy reveals that nanocrys-tals form within the nanoglasses during *** nanocrystal density correlates with higher nanoparticle crystallization enthalpy,an increase in plasticity,and a decrease in yield *** strain of 5.0%,yield strength of 3.8 GPa,and ultimate compressive strength of 2.7-3.8 GPa were *** show that the compaction of colloidal metallic glass nanoparticles results in robust bulk samples,with mechanical properties similar to that of other iron-based bulk metallic glasses.

关键词： Colloidal Nanoparticles Interface Nanoindentation Micropillar Plasticity

Unusual He-ion irradiation strengthening and inverse layer thickness-dependent strain rate sensitivity in transformable high-entropy alloy/metal nanolaminates:A comparison of Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu vs Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu

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Journal of Materials Science & technology 2022年第21期116卷 199-213页

作者： Y.F.Zhao H.H.Chen d.d.Zhang J.Y.Zhang Y.Q.Wang K.Wu G.Liu J.Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

In this work,we prepare transformable HEA/Cu nanolaminates(NLs)with equal individual layer thick-ness(h)by the magnetron sputtering technique,i.e.,Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu and Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu,and comparatively study He-ion irradiation effects on their microstructure and mechanical *** ap-pears that the as-deposited HEA/Cu NLs manifest two size h-dependent hardness regimes(i.e.,increased hardness at small h and hardness plateau at large h),while the He-implanted ones exhibit monotonically increased *** to the fashion that smaller h renders less irradiation hardening in bimetal NLs,the Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs manifest the trend that smaller h leads to greater irradiation *** contrast,the Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs exhibit the maximum irradiation hardening at a critical h=50 *** this critical size,smaller h results in lower radiation hardening(similar to bimetal NLs),while above this size,smaller h results in greater radiation hardening(similar to Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs).Moreover,these transformable HEA/Cu NLs display inverse h-dependent strain rate sensitivity(SRS m)before and after He-ion ***,compared with as-deposited samples,the irradi-ated Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs display reduced SRS,while the irradiated Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs dis-play enhanced *** unusual size-dependent irradiation strengthening and inverse h effect on SRS in irradiated samples were rationalized by considering the blocking effects of He bubbles on dislocation nucleation and motion,i.e.,dislocations shearing or bypassing He bubbles.

关键词： High entropy alloy/metal nanolaminates Interfaces Irradiation hardening Strain rate sensitivity Size effects

Physical and Chemical Properties and Crystal Structure transformation of Beeswax during Heat treatment

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Natural Science 2014年第11期6卷 871-877页

作者： t. Espolov J. Ukibayev d. Myrzakozha P. Perez-Lopez Y. Ermolaev Kazakh National technical University Almaty Kazakhstan Kazakhstan-Japan Innovation Center Kazakh National Agrarian University Almaty Kazakhstan

the object of research is the wax as a waste product of bees in the steppe and mountain areas of Almaty region of Kazakhstan. Purpose: to study the structure parameters and the homologous phase composition, morphology waxes of alpine and mountain areas of Kazakhstan and the establishment temperature-dependent patterns of their atomic-crystalline state. Methods: Radiography, gas chromatography, scanning electron microscopy and chemical methods of separation of multicomponent systems. the results were obtained in the atomic crystal and molecular structures of beeswax depending on the districts collecting materials. the technique of obtaining radiographs after dissolving beeswax in benzene, hexane and xylene was used. Submitted thermo-radiographic study samples were obtained. Batch analysis thermo-radiographs waxes after treatment with benzene, hexane and xylene showed that their structure is essentially different from the source and closer to the spectra of the crystallized wax melted and due to annihilation of stacking faults waxes native atoms after their dissolution in hexane, benzene and xylene and subsequent their recrystallization. the results obtained allow expanding the amount of information on the physico-chemical processes and structural transformations in beeswax as a composite of different genesis biomaterial. Scope: Beekeeping, plant, structural and analytical chemistry, biotechnology and biocomposites.

关键词： Wax Composite Biomaterial Radiography defect Structure

Properties of Soils of Abandoned Coal Mine Industrial Areas (Primorsky Krai, Russia)

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Journal of Geoscience and Environment Protection 2018年第6期6卷 78-92页

作者： Olga d. Arefieva Valentina G. tregubova Natalya V. Gruschakova Valerij t. Starozhilov Far Eastern Federal University Vladivostok Russian Federation

Lipovtsy coal field mine №4 processed north-western reserves of Lipovtsy field in Primorski Krai (Russia). In 1997, the mine was declared unprofitable and was abandoned by natural flooding with no arrangement of mine water discharge and in 2005 it was fully flooded. the main sources of pollution in the studied area are spoil heaps (mine wastes), underspoil filtering waters and mine waters which are being discharged on the surface after finishing of “hydraulic funnel” artificial support. the study of technogenic landscape of abandoned mine industrial area showed that its morphologic form is dominated by spoil heaps. Soils located near mine waste body differ from benchmark soils by chemical properties and size distribution. the influence of active hydrochemical mine and drainage water flows is the reason of the above-mentioned variation in soil properties. Results showed that, there exist a high correlation ratios between chemical composition of mine waters and water extracts from soil: Between the alkalinity of mine waters and electrical conductivity of soil water extracts (r = 0.73), between mine water iron content and pH of soil water extract (r = −0.56), between the solid residue of mine waters and electrical conductivity of soil water extracts (r = 0.72), between the mine waters calcium content and electrical conductivity of soil water extracts (r = −0.75), between the alkalinity of mine waters and silicon dioxide content of soil water extracts (r = 0.61), between the mineralization of mine waters and chrome content of soil water extracts (r = 0.73).

关键词： Luvisols Gleysols Spoil Heaps Abandoned Coal Mines Heavy Metals

Segregation enabled outstanding combination of mechanical and corrosion properties in a FeCrNi medium entropy alloy manufactured by selective laser melting

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Journal of Materials Science & technology 2022年第4期99卷 207-214页

作者： Heng duan Bin Liu Ao Fu Junyang He tao Yang C.t.Liu Yong Liu State Key Lab of Powder Metallurgy Central South UniversityChangsha 410083China Max-Planck-Institut für Eisenforschung Max-Planck-βe 1Düsseldorf 40237Germany department of Materials Science and Engineering City University of Hong KongHong KongChina department of Mechanical Engineering City University of Hong KongHong KongChina

Selective laser melting(SLM)has the advantage in preparing supersaturated solid solutions due to its unique thermal field and high solidification *** this study,a face-centered cubic single-phase FeCrNi medium entropy alloy(MEA)with an ultrahigh Cr content(~35 at.%)was additively manufactured by *** as-built MEA shows a hierarchical microstructure of coarse columnar grains and submicron dislocation cell structures,where the cell boundaries are probed segregated with Cr and C and decorated with nano *** appearance of these dislocation barriers results in an excellent combination of strength(σ_(0.2)=745 MPa,σ_(UtS)=1007 MPa)and ductility(ε_(f)=31%).the current MEA also shows a superb corrosion resistance with a corrosion current density of 0.06μA cm^(−2) in 3.5 wt.%NaCl solution,which is far lower than that of 316 *** high content of solutioned Cr in the MEA ensures sufficient Cr supply to form an integrated Cr_(2)O_(3) passive film,and the large number of cell boundaries acting as the diffusion channels lead to the fast formation of a stable passive film over the alloy surface.

关键词： Selective laser melting Microsegregation Strength ductility Corrosion resistance