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Large scale silver nanowires network fabricated by meV hydrogen (H＋) ion beam irradiation

Chinese Physics B 2016年第4期25卷 268-273页

作者： Honey S Naseem S Ishaq A maaza m Bhatti m t Wan D Center of Excellence in Solid State Physics University of the Punjab Lahore Pakistan National Center for Physics Quaid-i-Azam University Islamabad 44000 Pakistan UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology College of Graduate Studies University of South Africa Muckleneuk ridge P. O. Box 392 Pretoria South Africa Nanosciences African Network (NANOAFNEt) iThemba LABS National Research Foundation Old Faure road P. O. Box 722 Somerset West 7129 South Africa Department of Physics Bahauddin Zakariya University Multan 60800 Pakistan School of materials Science and Engineering Shanghai University Shanghai 201900 China

A random two-dimensional large scale nano-network of silver nanowires （Ag-NWs） is fabricated by meV hydrogen （H＋） ion beam irradiation. Ag-NWs are irradiated under H＋ ion beam at different ion fluences at room temperature. the Ag-NW network is fabricated by H＋ ion beam-induced welding of Ag-NWs at intersecting positions. H＋ ion beam induced welding is confirmed by transmission electron microscopy （tem） and scanning electron microscopy （SEm）. moreover, the structure of Ag NWs remains stable under H＋ ion beam, and networks are optically transparent. morphology also remains stable under H＋ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under meV H＋ ion beam irradiation. the results exhibit that the formation of Ag-NW network proceeds through three steps： ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. this observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from meV to GeV. this high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices.

关键词： Ag nanowires H+ ion irradiation nanowelding large scale nano-network optical properties

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Influence of Heat Input on martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld metals

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Journal of materials Science & technology 2012年第4期28卷 343-352页

作者： m. mukherjee t.K. Pal Welding technology Centre Metallurgical and Material Engineering Department Jadavpur University

the effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel （409m） sheets （as received） with thickness of 4 mm was described in detail in this work. the welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires （308L and 316L） and shielding gas composition of Ar ＋ 5% CO2. the welded joints were evaluated by microstructure and charpy impact toughness. the dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy （SFE）, optical microscopy （Om） and transmission electron microscopy （tem）. It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

关键词： Heat input Ferritic-austenitic dissimilar weld martensite Grain size toughness

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methanol oxidation in acidic and alkaline electrolytes using PtRuIn/C electrocatalysts prepared by borohydride reduction process

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燃料化学学报 2018年第12期46卷 1462-1471页

作者： Santos m.C.L. Nandenha J. Ayoub J.m.S. Assumpao m.H.m.t. Neto A.O. Instituto de Pesquisas Energéticas e Nucleares IPEN/CNEN-SPAv.Prof.Lineu Prestes2242 Cidade UniversitáriaCEP 05508-000Sao PauloSPBrazil Universidade Federal de Sao Carlos UFSCar Campus Lagoa do Sino Rodovia Lauri Simoes de Barros Km 12 CEP 18290-000-Buri-Sao Paulo SP Brazil

PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. the synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( tem),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). the XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. temmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. the best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.

关键词： borohydride reduction process PtRuIn/C electrocatalysts methanol oxidation acidic and alkaline electrolytes polarization curves

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Antibacterial Characterization of Silver Nanoparticles against *** AtCC-15224

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Journal of materials Science & technology 2008年第2期24卷 192-196页

作者： m.Raffi F.Hussain t.m.Bhatti J.I.Akhter A.Hameed m.m.Hasan Department of Chemical and materials Engineering Pakistan Institute of Engineering and Applied Sciences(PIEAS)Islamabad-45650Pakistan Department of microbiology Faculty of Biological SciencesQuaid-i-Azam UniversityIslamabadPakistan Central Analytical Facility Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)Islamabad-45650Pakistan Physics Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)Islamabad-45650Pakistan

Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （tem）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEm） and tem studies showed that silver nanoparticles after interaction with *** have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.

关键词： Silver Nanoparticles Antibacterial Electron microscopy

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CO oxidation and 4-nitrophenol reduction over ceria-promoted platinum nanoparticles impregnated with ZSm-5 zeolite

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Journal of Rare Earths 2022年第8期40卷 1247-1254页

作者： Zeinhom m.El-Bahy mohammed t.Alotaibi Salah m.El-Bahy Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr City11884CairoEgypt Department of Chemistry Turabah University CollegeTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

Active new ceria-promoted platinum supported on ZSm-5 catalysts were prepared and characterized by X-ray diffraction(XRD),Fourier transform infrared spectra(FtIR),transform electron microscopy(tem),temperature programmed desorption(tPD),and FtIR of CO *** samples were prepared by the incipient wetness impregnation method and calcined at 500℃.the XRD patterns and FtIR spectra prove that the zeolite framework is kept unaltered after metal *** images prove the presence of Pt nanoparticles with particle size starting from 14 to 27 *** FtIR data suggest the formation of Pt-O-Ce ***-situ FtIR of CO adsorption over reduced samples proves the presence of Pt~0 only,and no Pt^(n+)-CO species are *** prepared catalysts were tested in both oxidation reaction(CO oxidation) in the gas phase and in reduction reaction(4-nitrophenol reduction) in the aqueous ***,CO oxidation by O_(2) results in the formation of a CO_(2) peak at 2347 cm^(-1) as the only CO oxidation product in the studied frequency *** intensity of the CO_(2) peak increases after the addition of Ce,and it is 4 times higher in Pt_(1) Ce_(0.5)ZSm-5 than that in the Ce-free *** to the FtIR data and previous reports,the increase in the catalytic activity may be due to the formation of Pt-O-Ce ***,Ce-promoted Pt_(1) ZSm5 also exhibits enhanced catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol by NaBH_(4) in the aqueous *** first-order rate constant of the reduction increases ≈13 times after incorporating equal ratios of Pt and Ce(Pt_(1) Ce_(1)ZSm-5),and the activation energy(E_(a)) decreases to 40% of that in the reaction over Pt_(1) ZSm-5.

关键词： 4-Nitrophenol CO oxidation tPD-CO Platinum-cerium ZSm-5 Rare earths

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Effect of equal channel angular pressing on aging treatment of Al-7075 alloy

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Progress in Natural Science:materials International 2015年第2期25卷 159-168页

作者： m.H.Shaeri m.Shaeri m.t.Salehi S.H.Seyyedein m.R.Abutalebi Department of metallurgy and materials Engineering Engineering Faculty Imam Khomeini International University Department of materials Science and Engineering Sharif University of Technology Department of metallurgy and materials Engineering Iran University of Science and Technology (IUST)

the effect of aging treatment on microstructure and mechanical properties of equal channel angular pressed Al-7075 alloy was *** Al-7075 alloy in the solid solution heat-treated condition was processed by equal channel angular pressing through route BCat both the room temperature and 120 1C. Only three passes of equal channel angular pressing was possible due to the low ductility of the alloy at both temperatures. Followed by equal channel angular pressing, the specimens have been aged at 120 1C for different aging times. mechanical properties were measured by Vickers microhardness and tensile tests and microstructural observations were undertaken using transmission electron microscopy, X-ray diffractometer as well as optical microscopy. microstructural investigations showed that ultrafine-grained materials with grain size in the range of 200–350 nm and 300–500 nm could be obtained after three passes of equal channel angular pressing at room temperature and 120 1C, respectively. Equal channel angular pressing of solid solution heat-treated Al-7075 alloy accelerates precipitation rate and subsequently leads to a significant decrease in aging time to attain maximum mechanical properties. Furthermore, it is possible to achieve maximum mechanical properties during equal channel angular pressing at 120 1C as a result of dynamic aging and formation of small η′ phase.

关键词： Equal channel angular pressing Grain refinement Aging treatment tem mechanical properties

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microstructure of Cu-based Amorphous Composite Coatings on AZ91D magnesium Alloy by Laser Cladding

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Journal of materials Science & technology 2009年第4期25卷 492-498页

作者： Kaijin Huang Changsheng Xie t.m. Yue State Key Laboratory of Advanced Welding Production technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of materials Processing and Die ＆ mould technology Huazhong University of Scienee and Technology Wuhan 430074 China Department of Industrial and Systems Engineering Hong Kong Polytechnic University Hung Horn Hong Kong China

to improve the sliding wear resistance of AZ91D magnesium alloy, Cu-based amorphous composite coatings made of Cuatti34Zr11Nis and Cu47ti34Zr11Ni8＋20 wt pct SiC powders were fabricated on AZ91D magnesium alloy by laser cladding, respectively. SEm （scanning electron microscopy）, EDS （energy dispersive X-ray spectroscopy）, XRD （X-ray diffraction） and tem （transmission electron microscopy） techniques were employed to study the phases of the coatings. the results show that the coatings mainly consist of amorphous phase and different intermetallic compounds. the reason of formation of amorphous phase and the function of SiC particles were explained in details.

关键词： Laser cladding Cu-based amorphous composite coating SiC particle AZ91D magnesium alloy

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Bifunctional luminescent and magnetic core/shell type nanostructures Fe_3O_4@CeF_3:tb^(3+)/SiO_2

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Journal of Rare Earths 2011年第12期29卷 1117-1122页

作者： m.Runowski t.Grzyb S.Lis Department of Rare Earths Faculty of ChemistryAdam Mickiewicz University

A facile co-precipitation and microemulsion methods were applied to obtain core/shell type nanoparticles. Cerium fluoride doped with terbittrn（Ⅲ） ions supplied intensive green luminescence of the system. Due to the presence of magnetite nanoparticles as cores, the prod- uct was highly sensitive to external magnetic field. Both sorts of nanostructures were encapsulated by silica shell. Such external layer of inert oxide can potentially increase the resistance of prepared nanostructttres to thermal oxidation, aggressive agents, changing ofpH or destructive radiation. morphology of the product was examined using transmission electron microscopy （tem）. Formations of the core/shell type nanostructures were clearly seen in the tem pictures. Powder X-ray diffraction （XRD） confirmed the structure of the products, their nanocrystallinity and amorphous nature of silica shell. Optical properties were investigated by measuring excitation and emission spectra. Such multifunctional luminescent and magnetic nanoparticles coated with easily functionalized silica shell could be applied in many field of science.

关键词： bifunctional nanoparticles magnetic nanoparticles luminescence core/shell rare earths

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Preparation of a New Polyoxometalate-based Nanoparticles

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Chinese Chemical Letters 2004年第6期15卷 714-716页

作者： XiaoHongWANG FengLI JingFuLIU m.t.POPE DepartmentofChemistry NortheastNormalUniversityChangchtm130024 DepartmentofChemistry GeorgetownUniversityWashingtonDC20057-1227U.S.A

Polyoxometalates (POms) α-K8 H6 [Si2W18ti6O77] (Si2W18ti6) loaded starch nanop-articles have been prepared and structurally characterized by elemental analyses, IR spectra and 29Si spectroscopy. the particle size of Si2W18ti6 /starch was estimated by a transmission electron microscope (tem) and a 1000HSA mALVIRN Zetasizer instrument. the result shows that the polyoxometalate retained the parent structure after encapsulated by starch microspheres.

关键词： Polyoxometalate nanoparticle synthesis.

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Effects of varying Alx moles on structure and luminescence properties of ZnAl_(x)O_(1.5x+1):0.1 mol%tb^(3+)nanophosphors prepared using citrate sol-gel method

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Journal of Rare Earths 2023年第3期41卷 358-364,I0002页

作者： V.m.maphiri L.t.melato m.R.mhlongo t.t.Hlatshwayo t.E.motaung L.F.Koao S.V.motloung Department of Physics Sefako Makgatho Health Science UniversityP.O.Box 94Medunsa0204South Africa Department of mathematics Non Destructive Testing and PhysicsVaal University of TechnologyAndries Potgieter BlvdVanderbijlpark1900South Africa Department of Physics University of PretoriaPretoria0002South Africa Department of Chemistry School of Science in the College of Science Engineering and TechnologyUniversity of South AfricaPreller StreetMuckleneuk RidgeCity of TshwaneP.O Box 392UNISA 0003South Africa Department of Chemistry Sefako Makgatho Health Science UniversityP.O.Box 94Medunsa0204South Africa Department of Physics University of the Free State(Qwaqwa Campus)Private Bag X13Phuthaditjhaba 9866South Africa Department of Chemical and Physical Sciences Walter Sisulu UniversityMthathaSouth Africa

Un-doped and ZnAl_(x)O_(1.5x+1):0.1 mol%tb^(3+)(ZAOt)nano-powders were synthesized via citrate sol-gel *** AIx moles were varied in the range of 0.25≤x≤*** X-ray powder diffraction(XRD)data reveal that for xthe prepared samples crystal structure consists of mixed phases of the cubic ZnAl_(2)O_(4) and hexagonal ZnO phases,while for x>1.5 the structure consists of single phase of cubic ZnAl_(2)O_(4).the Raman and Fourier-trans form infrared(FtIR)vibrational spectroscopy show the presence of vibrations emanating ZnAl_(2)O_(4) *** electron microscopy(SEm)and transmission electron microscopy(tem)show the presence of irregular sphere at x>2.0 attributed to ZnAl_(2)O_(4).the photoluminescence(PL)spectroscopy reveals emissions from both the host and tb^(3+)*** from tb^(3+)are observed at 382,414,439,458 nm and 489,545,585,621 nm,which were attributed to the^(5)D_(3)→^(7)F_(6,5,4,2) and ^(5^)D_(4)→^(7)F_(6,5,4,3),*** results confirm that the tb^(3+)occupation site depends on the Alx *** International Commission on Illumination(CIE)colour chromaticity shows that the emission colour can be tuned from blue to green by varying the AIx moles.

关键词： Citrate sol-gel ZnAl_(2)O_(4)/ZnO tb^(3+)-doped Al_(x)moles Photoluminescence Rare earths

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