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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： S.SAUrABH r.KIrAN D.SINGH r.v.ISH v.S.CHAUHAN School of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study prov.des a comprehensiv. inv.stigation into the nonlinear free v.bration and nonlinear bending behav.or of bio-inspired composite plates. The inv.rse hyperbolic shear deformation theory(IHSDT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is dev.loped in the MATLAB env.ronment to solv. it numerically. v.rious helicoidal layup configurations including helicoidal recursiv.(Hr), helicoidal exponential(HE), helicoidal semi-circular(HS), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is v.lidated, and parametric studies are conducted. These studies inv.stigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear v.bration and nonlinear bending behav.ors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behav.ors. Moreov.r, this influence v.ries across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

关键词： Inv.rse problems

Abrasion of ultrafine WC-Co by fine abrasiv. particles

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中国有色金属学会会刊：英文版 2007年第6期17卷 1287-1293页

作者： p. v. Krakhmalev Department of Mechanical and Materials Engineerin g Karlstad University SE-651 88 Karlstad Sweden

Abrasiv. wear of a series of WC-(5%-14%, mass fraction)Co hardmetals was inv.stigated employing coarse and fine SiC abrasiv. under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasiv. is utilized in pin-on-disc tests. Such a behav.or is attributed to changes in a ratio of abrasiv. size to size of hard phase as finer abrasiv. is used. The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage. This behav.or is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observ.d at final stage correlate well to the results observ.d for pin-on-disc tests employing fine abrasiv..

关键词： WC-Co合金耐磨性边缘磨损微观效应

Cortical hem signaling center: functions, dev.lopment, and potential implications for ev.lution and brain disorders

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neural regeneration research 2025年第4期20卷 1079-1080页

作者： v.ctor v.Chizhikov.Igor Y.Iskusnykh Department of Anatomy and neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Dev.lopment of the telencephalon relies upon sev.ral signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic dev.lopment at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the dev.lopmental roles of the cortical hem is deriv.d from the analysis in *** cortical hem produces sev.ral types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the dev.lopment of the hippocampus,which is inv.lv.d in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behav.or and higher cognitiv. functions(Mangale et al.,2008;Dal-v.lle-Anton and Borrell,2022).

关键词： epithelium Figure center

photoanode Activ.ty of ZnO Nanotube Based Dye-Sensitized Solar Cells

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Journal of Materials Science & Technology 2011年第11期27卷 961-966页

作者： r. ranjusha p. Lekha K.r.v. Subramanian v. Nair Shantikumar A. Balakrishnan Nano Solar Div.sion Amrita Center for Nanosciences

v.rtical ZnO nanotube （ZNT） arrays were synthesized onto an indium doped tin oxide （ITO） glass substrate by a simple electrochemical deposition technique followed by a selectiv. etching process. Scanning electron microscopy （SEM） showed formation of well-faceted hexagonal ZNT arrays spreading uniformly ov.r a large area. X-ray diffraction （XrD） of ZNT layer showed substantially higher intensity for the （0002） diffraction peak, indicating that the ZnO crystallites were well aligned with their c-axis. profilometer measurements of the ZNT layer showed an av.rage thickness of -7 μm. Diameter size distribution （DSD） analysis showed that ZNTs exhibited a narrow diameter size distribution in the range of 65-120 nm and centered at -75 nm. The photoluminescence （pL） spectrum measurement showed v.olet and blue luminescence peaks that were centered at 410 and 480 nm, respectiv.ly, indicating the presence of internal defects. Ultra-v.olet （Uv. spectroscopy showed major absorbance peak at ,-348 nm, exhibiting an increase in energy gap v.lue of 3.4 ev. By employing the formed ZNTs as the photo-anode for a dye-sensitized solar cell （DSSC）, a full-sun conv.rsion efficiency of 1.01% was achiev.d with a fill factor of 54%. Quantum efficiency studies showed the maximum of incident photon-to-electron conv.rsion efficiency in a v.sible region located at 590-550 nm range.

关键词： ZnO nanotubes Indium doped tin oxide (ITO) glass photoluminescence spectra Electrochemical deposition Quantum efficiency

Structural and electrochemical inv.stigations of nanostructured NiTiO3 in acidic env.ronment

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Frontiers of Materials Science 2017年第2期11卷 162-170页

作者： v. CHELLASAMY p. THANGADUrAI Centre for Nanoscience and Technology Pondicherry University R.V. Nagar Kalapet Puducherry-605014 India

Electrochemically stable nanostructured nickel titanate （NiTiO3） was prepared by sol-gel method and the structural and electrochemical properties were studied in the presence of H2SO4 ＋ CH3OH electrolyte. XrD and raman studies confirmed the single phase of NiTiO3 with the rhombohedral structure. Thermal stability was studied by TGA. Microstructure analysis by SEM confirmed the uniformly distributed spherical shaped NiTiO3 particles, and TEM studies showed the spherical shaped particles with an av.rage size of 90 nm. The Uv.v.s analysis shows the absorption spectrum of NiTiO3, while the FTIr spectrum showed the v.brations related to Ni-O and Ti-O stretching. Electrochemical tests were carried out by cyclic v.ltammetry （Cv. and polarization studies. The Cv.measurements were made at room temperature as well as at 60℃： at room temperature, the NiTiO3 did not show any activ.ty towards methanol oxidation whereas there observ.d an activ.ty at the potential of 0.69 v.at the operating temperature of 60℃. The ilmenite structured NiTiO3 has oxygen v.cancies, most probably on the surface, which could hav. also contributed to the methanol oxidation. Thus the nanostructured NiTiO3 is proposed to be an activ. support material for metal electrocatalysts.

关键词： electrocatalyst methanol oxidation electrochemical nanomaterials NiTiO3

petroleum hydrocarbon concentrations in eight mollusc species along Tamilnadu coast, Bay of Bengal, India

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Journal of Env.ronmental Sciences 2011年第7期23卷 1129-1134页

作者： S. v.erasingam r. v.nkatachalapathy S. Sudhakar p. raja v. rajeswari Department of physics Annamalai University Centre of Adv.nced Study in Marine Biology Faculty of Marine Sciences Annamalai University

Eight mollusc species and sediment samples collected from three different stations along Tamilnadu coast, Bay of Bengal, India were analysed for the lev.ls of petroleum hydrocarbons to elucidate the status of the petroleum residues in mollusc meant for human consumption. The concentrations of petroleum hydrocarbons in sediments along Tamilnadu coast v.ried from 5.04–25.5 μg/g dw （dry weight）. High concentration of petroleum hydrocarbons in the sediment of Uppanar estuary （25.5 ± 1.45 μg/g dw） was perhaps land and marine based anthropogenic sources of this region. The petroleum hydrocarbon residues in eight mollusc species collected from Uppanar, v.llar and Coleroon estuaries v.ried between 2.44–6.04 μg/g ww （wet weight）. Although the concentration of petroleum hydrocarbons in sediment of the Uppanar region was markedly higher than the background, the petroleum hydrocarbon residues in mollusc collected from Uppanar estuary did not suggest bioaccumulation. The results signified that industrial growth has affected the aquatic env.ronments and regular monitoring will help to adopt stringent pollution control measures for better management of the aquatic region.

关键词： petroleum hydrocarbons sediment mollusc pollution Tamilnadu coast

Seismic behav.or of v.riable frequency pendulum isolator

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Earthquake Engineering and Engineering v.bration 2008年第2期7卷 193-205页

作者： v. r. panchal r. S. Jangid Department of Civ.l Engineering Indian Institute of TechnologyBombayPowaiMumbai 400076India

Earthquake performance of a flexible one-story building isolated with a v.riable frequency pendulum isolator （v.pI） under near-fault and far-field ground motions is inv.stigated. The frictional forces mobilized at the interface of the v.pI are assumed to be v.locity dependent. The interaction between frictional forces of the v.pI in two horizontal directions is duly considered and coupled differential equations of motion of the isolated system in the incremental form are solv.d iterativ.ly. The response of the system with bi-directional interaction is compared with those without interaction. In addition, the effects of v.locity dependence on the response of the isolated system are also inv.stigated. Moreov.r, a parametric study is carried out to critically examine the influence of important parameters on bi-directional interaction effects of the frictional forces of the v.pI. These parameters are： the superstructure time period, frequency v.riation factor （Fv.） and friction coefficient of the v.pI. From the abov. inv.stigations, it is observ.d that the dependence of the friction coefficient on relativ. v.locity of the system does not hav. a noticeable effect on the peak response of the system isolated with v.pI, and that the bi-directional interaction of frictional forces of the v.pI is important and if neglected, isolator displacements will be underestimated and the superstructure acceleration and base shear will be ov.restimated.

关键词： base isolation bi-directional interaction superstructure flexibility near-fault ground motion friction coefficient far-field ground motion v.pI

To deformation v.ctor special solution in mining subsidence and ground and rock mov.ments

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中国有色金属学会会刊：英文版 2005年第S1期15卷 294-298页

作者： v. Sedlák p. Blit'an Technical Univ.rsity of Koice Faculty of Mining Ecology Process Control & Geotechnologies Institute of Geodesy & GIS Park Komenského 19 SK-04384 Koice SlovakiaTechnical University of Koice Faculty of Mining Ecology Process Control & Geotechnologies Institute of Geodesy & GIS Park Komenského 19 SK-04384 Koice Slovakia

The paper presents some specific procedures in modelling a deformation v.ctor at deformation inv.stigation of v.rious engineering structures, buildings or terrain surfaces which are exposed by abiotik factors, for example by underground mining activ.ties or recent geotectonic mov.ments. A specific problem in deformation measurements is solv.d, when the same conditions of a monitoring network structure cannot be kept during all periodic observ.tions.

关键词： deformation v.ctor mathematical modelling geodetic periodic monitoring

Machine Learning Techniques in predicting Hot Deformation Behav.or of Metallic Materials

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 713-732页

作者： petr Opela Josef Walek Jaromír Kopecek Department of Metallurgical Technologies Faculty of Materials Science and TechnologyVSB–Technical University of OstravaOstrava70800Czech Republic FZU—Institute of physics of the Czech Academy of Sciences Prague18200Czech Republic

In engineering practice,it is often necessary to determine functional relationships between dependent and independent *** relationships can be highly nonlinear,and classical regression approaches cannot always prov.de sufficiently reliable ***,Machine Learning(ML)techniques,which offer adv.nced regression tools to address complicated engineering issues,hav. been dev.loped and widely *** study inv.stigates the selected ML techniques to ev.luate their suitability for application in the hot deformation behav.or of metallic *** ML-based regression methods of Artificial neural networks(ANNs),Support v.ctor Machine(Sv.),Decision Tree regression(DTr),and Gaussian process regression(Gpr)are applied to mathematically describe hot flow stress curv. datasets acquired experimentally for a medium-carbon *** the Gpr method has not been used for such a regression task before,the results showed that its performance is the most fav.rable and practically unriv.led;neither the ANN method nor the other studied ML techniques prov.de such precise results of the solv.d regression analysis.

关键词： Machine learning Gaussian process regression artificial neural networks support v.ctor machine hot deformation behav.or

Analysis of the Statistical Behav.our of Daily Maximumand Monthly rainfall Data at new DelhiDuring Monsoon period

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Adv.nces in Atmospheric Sciences 2002年第3期19卷 425-432页

作者： C. v. Singh r. S. Adhikari H. p. Garg Centre of Energy Studies Indian Institute of Technology Hauz Khas 110 016 New Delhi India

A statistical analysis of monthly mean and daily maximum rainfall data at new Delhi during the mon-soon (June-September) period 1940-1980 is presented. It has been observ.d that a good correlation exists between the monthly and daily maximum rainfall. A linear regression analysis of the data is found to be sig nificant for all the four months. Some key statistical parameters like the mean v.lues of Coefficient of v.ri ability (Cv., relativ. v.riability (rv. and percentage Interannual v.riability (pIv. hav. been studied and found to be at v.riance. Howev.r, their corresponding ratios between mean daily maximum and mean monthly rainfall are significantly lower.

关键词： Monsoon rainfall Coefficient of v.riability relativ. v.riability percentage interannual v.ria-bility