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A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspir.d.helicoidal laminated composite structures

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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.VAISH V.S.CHAUHAN School of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspir.d.helicoidal composite laminates, inspir.d.by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspir.d.composite plates. The inverse hyperbolic shear.d.formation 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 developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(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 validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspir.d.composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspir.d.composite plate.

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Mineralogy, geochemistry and age dating of shear zone-hosted Nb-Ta-, Zr-Hf-, Th-, U-bearing granitic rocks in the Ghadir and El-Sella areas, South Eastern desert, Egypt

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Chinese Journal Of Geochemistry 2011年第4期30卷 453-478页

作者： Ali M.A. lentz d.r.2 Nuclear Materials Authority depatment of geology University of New Brunswick

The rare metal minerals of mineralized alter.d.granites within the Ghadir and El-Sella shear zones, are represented by betafite, U-minerals (uraninite and uranophane), zircon, monazite, xenotime, and rutile in the Ghadir shear zone. While they are columbite-tantalite minerals as ferrocolumbite, pyrochlore, and fergusonite, Th-minerals (cheralite, uranothorite, and huttonite monazite), Hf-zircon, monazite and xenotime in the El-Sella shear zone. Hf-zircon in the El-Sella and Ghadir shear zones (increasing from the core to the rim) contains high inclusions of U-Th, and rEE minerals such as cheralite, uranothorite, huttonite monazite and xenotime especially in the El Sella shear zone. The rare-metal minerals, identified from peralkminous granites of the shear zones are associated with muscovite, quartz, chlorite, fluorite, magnetite, and biotite that are restricted to the two shear zones. Uraninite (low Th content) occurring in the Ghadir shear zone indicates the hydrothermal origin, but there are thorite, uranothorite, cheralite, and Hf-zircon in the El Sella shear zone, also indicating the hyrothermal proccess after magmatic origin. Compositional variations of Ta/(Ta+Nb) and Mn/(Mn+Fe) in columbite from 0.07-0.42 and 0.04-0.33, respectively, and Hf contents in zircon are so high as to be 12%, especially in the rim in the El Sella shear zone. This feature re-flects the extreme degree of magmatic fractionation. Four samples from the alter.d.granites of the Ghadir shear zone also are very low in TiO2 (0.04 wt%-0.17 wt%), Sr [(82-121)×10-6], and Ba [(36-380)×10-6], but high in Fe2O3T (0.46 wt%-0.68 wt%), CaO (0.64 wt%-1.23 wt%), alkalis (8.59 wt%-8.88 wt%), rb [(11-203)×10-6], Zr [(98-121)×10-6], Nb [(9-276)×10-6], Ta [(2-139)×10-6], U [(14-63)×10-6], Th [(16-105)×10-6], Pb [(13-32)×10-6], Zn [(7-8)×10-6], Y [(15-138)×10-6], Hf [(3-9)×10-6], and ∑rEE [(81-395)×10-6, especially LrEE [(70-322)×10-6]. They are very high in Zr/Hf (15.07-85.96) and Nb/Ta (7.17-21.48), and low

关键词：剪切带矿物学花岗岩钽矿物锆石钽铌地球化学蝶

Characterization of water-in-cr.d. oil emulsions in oil spill response

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Journal of Environmental Sciences 2003年第4期15卷 506-509页

作者： MATHEr r.r. FOTHErINGHAM A.F. YANG r.d. HeriotWattUniversityScottishBordersCampus HeriotWattUniversityScottishBordersCampusHeriotWattUniversityScottishBordersCampus GalashielsUKGalashielsUKGalashielsUK

The formation of water in cr.d. oil emulsions occurs when cr.d. oils are spilled into sea. The water in cr.d. oil emulsions significantly change the properties of the spilled cr.d. oils and in turn influence the choices made relating to oil spill countermeasures. The water in cr.d. oil emulsions were characterized using various techniques in this study. The environmental scanning electron microscopy observation of water.d.oplets in the emulsions is also presented. It is a powerful tool in emulsion observations.

关键词： oil spill water in oil emulsions oil spill response dSC ESEM

Mineralogy and geochemistry of Nb-,Ta-,Sn-,U-,Th-,and Zr-bearing granitic rocks from Abu rusheid shear zones,South Eastern desert,Egypt

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Chinese Journal Of Geochemistry 2011年第2期30卷 226-247页

作者： Ali M.A. lentz d.r. Hall d.C. Nuclear Materials Authority P.O.530.El MaadiCairoEgypt department of Geology New Brunswick UniversityUNBCanada Microscopy and Microanalysis Facility New Brunswick UniversityUNBCanada

Granite-hosted,Nb-,Ta-,Sn-,U-,Th-,and Zr(Hf)-bearing mineralization from the Abu rusheid shear zones occurs about 97 km southwest of the town of Marsa Alam,South Eastern desert,*** SSE-trending brittle-ductile Abu rusheid shear zones crosscut the peralkalic granitic gneisses and cataclastic to mylonitic rocks(mylonite,protomlyonite,and ultramylonite).The northern shear zone varies in width from 1 to 3 m with a strike length of >500 m,and the southern shear zone is 0.5 to 8 m wide and >1 km *** shear zones locally host less alter.d.lamprophyre and locally shear.d.granitic aplite-pegmatite *** rare-metal minerals,identified from the peralkalic granitic gneisses and cataclastic to mylonitic rocks are associated with muscovite,chlorite,quartz,fluorite,pyrite,magnetite,and rare biotite that are restricted to the Abu rusheid shear zones;these are columbite-tantalite and pyrochlore(***) in the northern shear zone and ferrocolumbite in the southern shear *** occurs as inclusions in the columbite-tantalite minerals.U-and Th-minerals(uraninite,thorite,uranothorite,ishikawaite,and cheralite) and Hf-rich zircon ***(?) zircon contains numerous inclusions of rutile,fluorite,U-Th and rEE minerals,such as uranothorite,cheralite,monazite,and *** variations in Ta/(Ta+Nb) and Mn/(Mn+Fe) in columbite range from 0.07-0.42 and 0.04-0.33,respectively,and Hf contents in zircon from 1.92-6.46 of the two mineralized shear zones reflect the extreme degree of magmatic *** samples of peralkalic granitic gneisses and cataclastic to mylonitic rocks from the southern shear zone have very low TiO2(0.02 wt%-0.04 wt%),Sr [(15-20)×10-6],and Ba [(47-78)×10-6],with high Fe2O3T(0.94 wt%-1.99 wt%),CaO(0.14 wt%-1.16 wt%),alkalis(9.2 wt%-10.1 wt%),rb [(369-805)×10-6],Zr [(1033-2261)×10-6],Nb [(371-913)×10-6],U [(51-108)×10-6],Th [(36-110)×10-6],Ta [(38-108)×10-6],Pb [(39-364)×10-6],Zn [(21-424)×10-6],Y [(8-304)×10-6],Hf

关键词： uranium thorium zircon columbite-tantalite fluorite monazite xenotime age dating granitic gneisses South Eastern desert Egypt

STUdY ON PrOPErTIES OF PULSE ELECTr.d.POSITEd rE-Ni-W-P-SiC COMPOSITE COATINGS

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Acta Metallurgica Sinica(English Letters) 2007年第2期20卷 111-116页

作者： Z.C. Guo X.Y. Zhu r.d. Xu Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology Kunming 650093 China

The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electr.d.posited rE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of rE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the rE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and rE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of rE-Ni-W-P-SiC composite coatings are not obvious. The hardness of rE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of rE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.

关键词： frequency duty cycle electr.d.position rE-Ni-W-P-SiC composite coating

Polyethylene glycol fusion repair of sever.d.rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord

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Neural regeneration research 2025年第7期20卷 2095-2107页

作者： Emily A.Hibbard Liwen Zhou Cathy Z.Yang Karthik Venkudusamy Yessenia Montoya Alexa Olivarez George d.Bittner.d.le r.Sengelaub Program in Neuroscience Indiana UniversityBloomingtonINUSA department of Neuroscience University of Texas at AustinAustinTXUSA

Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically *** used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of sever.d.proximal and distal axons in rat sciatic *** have previously reported that sciatic nerve axons repair.d.by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor ***,our previous report showed that PEG-fusion of sever.d.sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target *** this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic *** adult male and female rats(Sprague–dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of *** action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury *** success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days *** 2–42 days postoperatively,we anterogr.d.ly labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intr.d.rmal injection of wheat germ agglutinin conjugated horser.d.sh ***-fusion repair reestablished axonal *** to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal ***,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repa

关键词： axotomy dorsal horn peripheral nerve injury plasticity polyethylene glycol(PEG) sciatic nerve sensory terminals wheat germ agglutinin horser.d.sh peroxidase

Geochemical and Nd-Sr Isotopic Compositions of Hypabyssal Adakites in the Tor.d.Ahmad Abad Magmatic Belt,Northern Central Iran Zone:Analysis of Petrogenesis and Geodynamic Implications

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Journal of Earth Science 2021年第6期32卷 1428-1444页

作者： Fazilat Yousefi ryan d.Mills Mahmoud Sadeghian david r.lentz Christina Wanhainen Habibollah Ghasemi Laicheng Miao department of Earth Sciences University of New BrunswickFrederictonCanada department of Geological Sciences University of North Carolina at Chapel HillChapel HillUSA Faculty of Earth Sciences Shahrood University of TechnologyShahroodIran department of Civil Environmental and Natural Resources EngineeringLulea University of TechnologyLuleaSweden Institute of Geology and Geophysics Chinese Academy of SciencesBeijing100029China

Eocene intermediate to felsic subvolcanic rocks of the Tor.d.Ahmad Abad magmatic belt(TAMB),in the northern part of the Central Iran zone,are exposed between the Tor.d.and Ahmad Abad regions in South-Southeast *** igneous rocks include hypabyssal dacite,trachyte,andesite,trachy-andesite,and basaltic andesite;they are mainly composed of phenocrysts and microcrystalline groundmass of pyroxene,amphibole,and plagioclase,with minor biotite and titanomagnetite;they form domal structures(plugs and stocks),dikes,and sills that intr.d.d into Neoproterozoic to cogenetic Eocene volcano-sedimentary *** on isotopic analysis of these intermediate to acidic rocks,initial ratios of^(143)Nd/^(144)Nd range from 0.512775 to 0.512893 and initial ratios of^(87)Sr/^(86)Sr range from 0.703746 to 0.705314,with quite positiveε_(Nd(i))values of+3.69 to+*** are enriched in light rare earth elements and large ion lithophile elements and depleted in heavy rare earth elements and high-field strength elements,the SiO_(2) content is(52-62)wt.%,and Na_(2)O content>3 wt.%,Al_(2)O_(3) content>16 wt.%,Ybd Yd Sr and Nd isotopic data are consistent with adakitic signatures originating by partial melting of the subducted Neo-Tethys oceanic slab(Sabzevar branch)and lithospheric suprasubduction zone *** mantle signatures typifying the rapidly emplaced adakitic rocks(slab(high-silica adakite)and suprasubduction zone(low-silica adakite)melts)together with their locally voluminous extent are evidences that support a locally extensional geodynamic setting;and the evidence is consistent with an evolution to local transpression in the Late Eocene in this convergent margin are environment to rifting(basalts to adakites)towards submarine conditions in the Neogene.

关键词： isotope geochemistry adakite rocks Central Iran zone Shahrood Iran

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TIPS FOr PArENTS :FOOd ANd drINK FOr YOUNG ATHLETES

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中国运动医学杂志 2000年第4期 447-448页

作者： ruth Carey r.d. L.d. Oregon Nutrition Consultant Portland

Prognostication of hydrocarbon generative potential in the onshore and offshore Niger.d.lta, Nigeria using TOC content and rock-eval pyrolysis techniques

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Chinese Journal Of Geochemistry 2014年第2期33卷 138-144页

作者： Nyantakyi E.K. Li Tao Hu Wangshui Borkloe J.K. Nagre r.d. Civil Engineering department Kumasi Polytechnic School of Earth Science Yangtze University Chemical Engineering department Kumasi Polytechnic College of Petroleum Engineering Yangtze University

This article prognosticates the hydrocarbon generation potential of core samples from fields A, B, C and d in Niger.d.lta, Nigeria. The objectives of this study are to characterize the quality of these core samples by organic geochemical analyses. A total of ten core samples collected from fields A, B, C and d in Niger.d.lta were analyzed using total organic carbon(TOC) content analysis, rock-eval pyrolysis technique. The analytical results of the studied core samples reveal that they have generally high total organic carbon contents(TOC), suggesting that conditions in the Niger.d.lta favour organic matter pr.d.ction and preservation. There is a variation in the kerogen types and this may be attributed to the relative stratigraphic positions of the core samples within the Niger.d.lta. The rock-eval results indicate that the samples from fields C and d contain pr.d.minantly Type II kerogen with a capacity to generate oil and gas and hence have good generative potential. The samples from fields A and B contain mainly Type III kerogen and are gas-prone with moderate generative potential.

关键词：尼日尔三角洲热解技术尼日利亚生烃潜力 TOC 岩石潜力预测干酪根类型