DOCSLIB.ORG

Mas A~Iro.K~Noo Ka^No,， T~Da?Tadao Lwataiwata合 Eiichieiich I Kurakuramot皿oto-- O ，, Minoruminor U Takenaka--Takenaka Andan D Sadaesada E Yayamaguch皿aguchi I

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mas A~Iro.K~Noo Ka^No,， T~Da?Tadao Lwataiwata合 Eiichieiich I Kurakuramot皿oto-- O ，, Minoruminor U Takenaka--Takenaka Andan D Sadaesada E Yayamaguch皿aguchi I 'r PrProcaadng田崎dinga s ofof 世帽民削白川町田信副首..itw Fourth Intamtional 5"Symposiu暗闘..... m 。oan ADVANCEDADVANCE D 鈍NUCLEAUCLEAII R ENERGYENERG Y RESTRESEARC由CHH ROLES ASDAXO DIRECTIO.... DIRECTIOX OF 且MATERIALrA TE RlA ι SCISCIEXCE E. ... CE 1: IX、.. .w' SVCLEARc. ιEAR TECHXOLOGYTECH I'> OLOG1' POSITRONPOSITRO N ANNIBIANNIHILATIOL& TION N STUDYSTUD Y OFO P GlUlGRAPHITEPIUTE ,， GGLASSLIlS SYY CaRBONCARBO N JUQ)AN D C60/C70Cfi0 /C7o FULLDEFULLEREN蜘EE 阿Masayukasa 抑制i HHasegawa管記~gawa,， MasahirMas_a~iro.K~noo Ka^no,，_ T~da?Tadao lwataIwata合 EiichiEiich i KuraKuramot皿oto-- o ，, MinoruMinor u Takenaka--Takenaka andan d SadaeSada e YaYamaguch皿aguchi i InstituteInstitut e forfo r MaterialsMaterial s Research ,， TohokuTohok u University ,， SendaiSenda i 980 ,， JapanJapa n _. * _. PhonePhon e 022-227-6200022-227-620 0 eext.2454.認 t.2454 ， FaxFa x 022-215-2061022-215-206 1 PhysicsPhysic s DeDepartmentpartment ,， JapanJapa n AtomicAtoni c EnEnergergy y ResearchResearc h lnstituteInstitute,， TOkaiTokai,， IbarakiIbarak i 319319-11・11 ,， JapanJapa n 合会 PhonePhon e 0292-82-5470 ,， FaxFa x 0292-820292-82-529・5297 7 * ResearchResearc h InstituteInstitut e forfo r App1iedApplie d MeMechanicschanics ,， Kyusyu Kyusy u UniversityUniversity,， Kasuga ,， FukuokaFukuok a 816 ,， JapanJapa n PhonePhon e 092-573092-573-961・9611 1 ext.ext . 566 ,， FaxFa x 092-582092-582-420・4201 1 且ABSTRACTBSTR 且.CT: : ACARACA R ( AnAngulagular r CoCorrelatior. relation n ofo f AnnihilationAnnihilatio n Radiation)Radiation ) andan d positronpositro n Keyword*K~yword.:: PositronPositro n AnnAnnihilationihilation ,， lifetimelifetim e measurementsmeasurement s havehav e beenbeen 皿madade e on,， Graphite, Glassy Carbon, C , Fullerene, Graphite ， G1assy Carbon ， C 6600' Fu11erene ， HOPGHOP G (High1y(Highl y OrientedOriente d PyrPyrolytio1ytic c Graph-Graph­ Void ,， Pore ,， VoidVoi d TrappingTrapping~-Soccer, Soccer 8a11Bal l ite) ,， isotropicisotropi c fine-grainedfine-graine d graphite ,， VacancyVacanc y glassyglass y carbonscarbon s andan d C60/C70C50/C7 Q P?wder._powder . HOPGHOP G showedshowe d markedmarke d bimodalitybimodalit y a10ngalon g theth e c-c- axisaxi s andan d anisotropyanisotrop y ini n ACARACA R momentummomentu m 1.1.INTRODUCTIOlM'l'R ODUCT l: ONN distribution ,， whichwhic h stemste m fromfro m character-character­ isticisti c annihi1ationannihilatio n betweenbetwee n "inter1ayer""interlayer " GraphiteGraphit e hasha s beenbee n emp10yedemploye d asa s theth e posipositron trons s andan d 1[T-electron -e1ectrons s ini n graphigraphite te. 圃moderatooderator r andan d structura1structura l cocomponent岨lponents s ofo f ACARACA R curvescurve s ofo f theth e isotropicisotropi c graphitegraphit e fissionfissio n reactors ,， suchsuc h asa s gas-cooledgas-coole d andan d glassyglass y carbonscarbon s arear e eveneve n narrowernarrowe r one ,， becausebecaus e ofo f 10wlo w neutronneutro n crosscros s sec-sec­ thantha n tDattf^a t ofo f HOPGHOP G perpendicu1arperpendicula r tot o theth e tion ,， chemica1chemica l stabi1itystabilit y andan d highhig h melt-melt­ c-axis.c-axis . PositronPositro n 1ifetimeslifetime s ofo f 42042 0and and ingin g point.point . FurtherFurthe r recentlyrecentl y carboncarbo n 39039 0 - 48048 0 psec ,， muchmuc h longerlonge r thantha n thattha t ofo f materia1smaterials,， forfo r exampleexampl e graphitegraphit e andan d 22122 1 psecpse c ini n HOPG ,， werewer e observedobserve d forfo r theth e cabon-carboncabon-carbo n composites ,， havehav beco e becom圃e oneon e isotropicisotropi c graphitegraphit e andan d g1assyglass y carbonscarbon s ofo f theth e keyke y materialsmaterial s ini n theth e fie1dfiel d ofo f respective1yrespectively,， which whic h arear e duedu e tot o positronpositro n plasma-wa11plasma-wal l lnteractioninteractio n ini n fusionfusio n reac-reac­ trappingtrappin g ini n structura1structura l voidsvoid s ini n them.them . torstor s becausebecaus e ofo f itsit s 10wlo w atomicatomi number c number PositroPositron n 1ifetimelifetim e anand d ACAACAR R widtwidth h (FWHM)(FWHM ) anand d high-temperaturehigh-temperatur e characteristics.characteristics . canca n beb e we11wel l correlatedcorrelate d tot o voidvoi d sizessize s ForFo r fusionfusio n reactorreacto r app1icationapplication,， absorp-absorp­ (1.7(1. 7 tot o 5.05. 0 nm)nm ) oro f g1assyglass y carbonscarbon s whichwhic h tiontio n andan d desorptiondesorptio n ofo f hydrogenhydroge n isotopeisotop e havenav e beenbee n determineddetermine d byb y sma11smal l ang1eangl e atomsatom s arear e veryver y iimportan田lportant t andan d sensensitivel!l!:t- tive1y y neutronneutro n (SAN)(SAN ) scatteringscatterin g measuremeasur e .-唖 •intsnts. affectedaffecte d byb y structuralstructura l voids..void s J' andan d ACARACA R ..:urves curves andan d posipositro tron n 1ifetilifetiml' .e e ofo f radiation-inducedradiation-induce d vacanciesvacancie s andan d voidsvoids. C60/C70CCQ/C7 0 powderpowde r ag~eagree we11wel l withwit h thosethos e ofo f Consequent1yConsequentl y atomisticatomisti c informationinformatio n andan d gIassy-carbons.glass y carbons. ThisThi s showsshow s thattha t positronpositro n characterizationcharacterizatio n ofo f structuralstructura l voidsvoid s andan d wavewav e functionsfunction s extend ,， asa s ini n theth e voidsvoid s radiation-inducedradiation-induce d defectsdefect s isi s veryver y necesneces- ­ ofo f glassyglass y carbons ,， muchmuc h widerwide r thantha n openope n sary.sary . PositronPositro n annihi1ationannihilatio n hasha s beenbee n spacesspace s ofo f theth e octahedraloctahedra l intersticesinterstice s ofo f successivelysuccessivel y useduse d forfo r studiesstudie s ofo f vacan-vacan­ theth e face-centeredface-centere d cubiccubi c (FCC)(FCC ) structurestructur e ciescie s andan d voidsvoid s ini n meta1smetal s 【[1]1]. ForFo r ofo f C60C 60 crysta1crysta l andan d stro~g1ystrongly suggest~suggests carboncarbo n materia1smaterial s theth e usefu1nessusefulnes s ofo f thisthi s positionpositro n trappingtrappin g ini n thethe 町"soccesoccer r ballba11" " techniquetechniqu e hasha s beenbee n demonstrateddemonstrate d byb y vacancy.vacancy . Possib1ePossibl positron e positron statesstate s ini n theth e severa1severa l workersworker s [2[2-6]・6]. carboncarbo n materialsmaterial s arear e discusseddiscusse d withwit h a simp1esimpl e modelmode l ofo f voidvoi d volume-trapping.volume-trapping . *) ' sometimessometime s ca1ladcal l 3d asa s cavitiescavitie s oro r Pre1iminaryPreliminar y resu1tsresult s ono n neutronneutro n irradia-irradia­ pores.pores . tiontio n damagedamag e ini n HOPGHOP G arear e a1soals o presented.presented . - 119-119 • --， RecenRecent t excitinexciting g reporreport t oof f methomethod d merit国 ents s oon n HOPG,， glassg1assy y carboncarbons s anand d fofor r preparinpreparing g larglarge e quantitiequantities s oof f ththe e CCQ/C~~0/C707Q _powderpowde r wilwi11 l bbee compareco 園 ipared d anand d "socce"soccer r ballball" " CC60 60 moleculemolecules s [7[7] ] anand d ththe e discussediscussed d witwith h a simplsimple e void-trappingvoid-trappin g followinfollowing g discoverdiscovery y oof f superconductivitsUp'~rconductivityy modelmode1. iin n potassium-dopepotassium-doped d C民6nQ [8[&] ] havhave e raiseraised d greagreat t interesinterest t iin n ththe e structurstructure e anand d 2 2. DPEXPERIMENTAEIUMEN'1' AL L propertieproperties s oof f thithis s allotropia11otropic c forform m oof f carbocarbon n [9,10][9 ，10]. BecausBecause e oof f ththe e weaweak k FigurFigure e 1 showshows s crystacrysta1 l structuresstructure s intermoleculaintermo1ecu1ar r interaction,， ththe e solisolid d oof f diamondiamond d (a)(a )， , graphitgraphi te e (b )】 anand d ththe e C60 hahas s larg1arge e opeopen n spaces, fofor r example , (100(100) ) facface e oof f ththe e FCFCC C C - SampleSamples s useused d 6 ， ， 60 ・ aat- t ththe e octahedraoctahedral l intersticeinterstices s wherwhere e i:L n thi悦1I s studstudy y arare e listelisted d iin n Tab.lTab.1. A potassiupotassiurn m atomatorns s cacan n bbee accommodateaccornrnodated d iin n singlsingle e crystacrystal l platp1ate e oof f synthetisynthetic c diadia- ­ itits s structurestructure. ConsequentlConsequently y iit t iis s ververy y mon皿ond d witwith h (111(111) ) crystacrysta1 l facface e wawas s used.used . interestininteresting g tto o investigatinvestigate e positronpositro n HighlHighly y orienteoriented d pyrolytipyr01ytic c graphitegraphit e statestates s iin n soliso1id d CgC60 andQ and tto o comparcompare e thethern m (HOPG(HOPG) ) (2Y(ZYA A anand d ZYZYH H grade.， Unio Union n CarbideCarbid e witwith h thosthose e iin n graphitgraphite e anand d glassg1assy y ( Co.Co.) ) slabslabs s havhave e mosaimosaic c structurstructure e witwith h glass-likglass-like e ) carboncarbon. ththe e well-orientewe11-oriented d c-axic-axis s bubut t witwith h randorandom m orientatioorientation n oof f ththe e crystallitecrysta11ites s iin n ththe e RecentlRecent1y positron y positron lifetimlifetime e measuremeasure- ­ basabasal l planeplane. ThThe e averagaverage e crysta11itecrystallit e mentments s havhave e beebeen n carriecarried d ouout t bby y severasevera1 l sizsize e alona10ng g ththe e a-axia-axis s iis s abouabout t 225μm5 a m groupgroups s [11-13](11-13] ,， includininc1uding g uus s [6][6]. whilwhi1e e Turn7μ 皿 alona10ng g ththe e c-axic-axis s [3][3]. H0PGHOPG- - FurtheFurther r theoreticatheoretica1 l calculationca1cu1ations s shoshow w ZYZYA A wawas s subjectesubjected d tto o fasfast t neutroneutrop_ n irrairra= ; 18 4 positropositron n statestates s anand d lifetime1ifetimes_in_C60 s in C60 anand d diatiodiation n witwith h fluencf1uence e oof-8.3-~-iõI8f 8.3 x 10 n/car~/C;2 potassium-dopepotassium-doped d fullerenefu11erenes s [14,15][14 ， 15]~-. A11Al l aat t abouabout t 150°150 ・C iin n ththe e JMTJMTR R reactorreactor. TheTh e thesthese e experimentae 翠perimenta1 l studiestudies s havhave e reportedreporte d blochl~_ofk of HOPG-ZYHO fG -ZYH H 町wa'as s irradiateirradiated d tto o 1.41. 4 a positronpositro n 1ifetimelifetim e ofo f aboutabou t 40040 0 psecpse c ini n x 1010~u20 n/cmn/cm~2 ata t aboutabou t 6060 ・"CC inin 位田the JRR-2JRR- 2 C powders.powders .
Load more

Recommended publications
  • Graphene – Diamond Nanomaterials: a Status Quo Review
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 29 July 2021 doi:10.20944/preprints202107.0647.v1 Article Graphene – diamond nanomaterials: a status quo review 1 Jana Vejpravová ,* 1 Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic. * Correspondence: JV, [email protected] Abstract: Carbon nanomaterials with a different character of the chemical bond – graphene (sp2) and nanodiamond (sp3) are the building bricks for a new class of all-carbon hybrid nanomaterials, where the two different carbon networks with the sp3 and sp2 hybridization coexist, interact and even transform into one another. The unique electronic, mechanical, and chemical properties of the two border nanoallotropes of carbon ensure the immense application potential and versatility of these all-carbon graphene – diamond nanomaterials. The review gives an overview of the current state of the art of graphene – diamond nanomaterials, including their composites, heterojunctions, and other hybrids for sensing, electronic, energy storage, and other applications. Also, the graphene- to-diamond and diamond-to-graphene transformations at the nanoscale, essential for innovative fabrication, and stability and chemical reactivity assessment are discussed based on extensive theo- retical, computational, and experimental studies. Keywords: graphene; diamond; nanodiamond; diamane; graphene-diamond nanomaterials; all car- bon materials; electrochemistry; mechanochemistry; sensor; supercapacitor;
    [Show full text]
  • Evidence for Glass Behavior in Amorphous Carbon
    Journal of C Carbon Research Article Evidence for Glass Behavior in Amorphous Carbon Steven Best , Jake B. Wasley, Carla de Tomas, Alireza Aghajamali , Irene Suarez-Martinez * and Nigel A. Marks * Department of Physics and Astronomy, Curtin University, Perth, WA 6102, Australia; [email protected] (S.B.); [email protected] (J.B.W.); [email protected] (C.d.T.); [email protected] (A.A.) * Correspondence: [email protected] (I.S.-M.); [email protected] (N.A.M.) Received: 15 July 2020; Accepted: 24 July 2020; Published: 30 July 2020 Abstract: Amorphous carbons are disordered carbons with densities of circa 1.9–3.1 g/cc and a mixture of sp2 and sp3 hybridization. Using molecular dynamics simulations, we simulate diffusion in amorphous carbons at different densities and temperatures to investigate the transition between amorphous carbon and the liquid state. Arrhenius plots of the self-diffusion coefficient clearly demonstrate that there is a glass transition rather than a melting point. We consider five common carbon potentials (Tersoff, REBO-II, AIREBO, ReaxFF and EDIP) and all exhibit a glass transition. Although the glass-transition temperature (Tg) is not significantly affected by density, the choice of potential can vary Tg by up to 40%. Our results suggest that amorphous carbon should be interpreted as a glass rather than a solid. Keywords: amorphous carbon; liquid carbon; glass-transition temperature; molecular dynamics 1. Introduction Amorphous carbons are often described as one of the allotropes of carbon, along with graphite, diamond and fullerenes.
    [Show full text]
  • Fabrication of Glassy Carbon Microstructures by Soft Lithography
    Sensors and Actuators A72Ž. 1999 125±139 Fabrication of glassy carbon microstructures by soft lithography Olivier J.A. Schueller, Scott T. Brittain, George M. Whitesides ) HarÕard UniÕersity, Department of Chemistry and Chemical Biology, 12 Oxford Street, Cambridge, MA 02138, USA Received 22 April 1998; revised 10 August 1998; accepted 10 August 1998 Abstract This paper describes fabrication techniques for the fabrication of glassy carbon microstructures. Molding of a resin of polyŽ furfuryl alcohol. using elastomeric molds yields polymeric microstructures, which are converted to free-standing glassy carbon microstructures by heating Ž.T ;500±11008C under argon. This approach allows the preparation of macroscopic structures Ž several mm2. with microscopic features Ž.;2 mm . Deformation of the molds during molding of the resin allows preparation of curved microstructures. The paper also presents a method of incorporating these structures on a chip by masking and electroplating. q 1999 Elsevier Science S.A. All rights reserved. Keywords: Glassy carbon; Microfabrication; Soft lithography 1. Introduction dielectrics are deposited and patterned onto the surface; subtractive processes are based on etching. The range of This paper describes the preparation of glassy carbon structures that can be generated by etching is constrained microstructures by a procedure in which the microstruc- by the requirement of some etching procedures for specific tures of polymeric precursors to carbon are first formed by crystalline orientation: curved or rounded structures may wx micromolding, and then converted to glassy carbon by heat be particularly difficult to make 4 . treatmentŽ. 500±11008C under an inert atmosphere. Re- We have recently developed a range of microfabrication markably, the overall structure of the polymeric shape is techniques for the preparation of microstructures in or- wx largely retained during the carbonization stage, and the ganic polymers 7,8 .
    [Show full text]
  • The R3-Carbon Allotrope
    The R3-carbon allotrope: a pathway towards glassy carbon under high SUBJECT AREAS: MECHANICAL pressure PROPERTIES ELECTRONIC MATERIALS Xue Jiang1,2, Cecilia A˚ rhammar3, Peng Liu1, Jijun Zhao2 & Rajeev Ahuja1,4 STRUCTURE OF SOLIDS AND LIQUIDS 1Department of Materials and Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden, 2Key Laboratory of Materials ELECTRONIC STRUCTURE Modification by Laser, Ion and Electron Beams Dalian University of Technology, Ministry of Education, Dalian 116024, China, 3Sandvik Coromant, Lerkrogsv. 13, S-126 80 Stockholm, Sweden, 4Department of Physics and Astronomy, Box 516, Uppsala University, 75120, Uppsala, Sweden. Received 8 November 2012 Pressure-induced bond type switching and phase transformation in glassy carbon (GC) has been simulated Accepted by means of Density Functional Theory (DFT) calculations and the Stochastic Quenching method (SQ) in a 25 April 2013 wide range of pressures (0–79 GPa). Under pressure, the GC experiences a hardening transition from sp- and sp2-type to sp3-type bonding, in agreement with previous experimental results. Moreover, a new Published crystalline carbon allotrope possessing R3 symmetry (R3-carbon) is predicted using the stochastic SQ 23 May 2013 method. The results indicate that R3-carbon can be regarded as an allotrope similar to that of amorphous GC. A very small difference in the heat of formation and the coherence of the radial and angular distribution functions of GC and the R3-carbon structure imply that small perturbations to this crystalline carbon Correspondence and allotrope may provide another possible amorphization pathway of carbon besides that of quenching the liquid melt or gas by ultra-fast cooling. requests for materials should be addressed to J.Z.
    [Show full text]
  • High-Pressure Tetrahedral Amorphous Carbon Synthesized By
    pubs.acs.org/JPCC Article High-Pressure Tetrahedral Amorphous Carbon Synthesized by Compressing Glassy Carbon at Room Temperature Lijie Tan, Hongwei Sheng, Hongbo Lou, Benyuan Cheng, Yuanyuan Xuan, Vitali B. Prakapenka, Eran Greenberg, Qiaoshi Zeng, Fang Peng, and Zhidan Zeng* Cite This: J. Phys. Chem. C 2020, 124, 5489−5494 Read Online ACCESS Metrics & More Article Recommendations ABSTRACT: Tetrahedral amorphous carbon(ta-C) thin films with high sp3 fraction have extraordinary mechanical properties and wide applications. Despite intensive effort to increase the thickness of ta-C thin films in the past decades, bulk ta-C has not been achieved until date. In this study, by compressing a sp2- bonded amorphous carbon (glassy carbon) up to 93 GPa, we demonstrate that the formation of bulk ta-C is possible at high pressures and room temperature. We studied the atomic structure, stability, and mechanical properties of the ta-C synthesized under high pressure using in situ high-pressure X-ray diffraction and large-scale first-principles calculations. The high-pressure ta-C is mainly tetrahedrally bonded, with relatively large distortions in the sp3 C−C bonds. It can be preserved to approximately 8.5 GPa during pressure release, below which it transforms to disordered glassy carbon, accompanied by sp3-to-sp2 transition. Moreover, both the experiment and simulation show that the high-pressure ta-C has a high bulk modulus (363 ± 29 GPa, experimental) even comparable to diamond. These results deepen our understanding of amorphous carbon and help guide the synthesis of novel carbon materials using high pressure. − 1. INTRODUCTION bonding transitions under pressure.10,14 16 Utilizing the effect 3 Carbon forms a great variety of crystalline and disordered of pressure, various sp -bonded carbon forms have been structures owing to its flexibility in bonding (sp1-, sp2-, and sp3- synthesized by high-pressure and high-temperature (HPHT) hybridized bonds).
    [Show full text]
  • TEM Study of Amorphous Carbon with Fully Sp3-Bonded Structure
    2268 Microsc. Microanal. 23 (Suppl 1), 2017 doi:10.1017/S1431927617012004 © Microscopy Society of America 2017 TEM Study of Amorphous Carbon with Fully sp3-Bonded Structure Jianguo Wen1, Zhidan Zeng2, Liuxiang Yang2,3, Qiaoshi Zeng2, Hongbo Lou2, Hongwei Sheng2, Dean J. Miller1, Wenge Yang2,3 Ho-kwang Mao2,3 1Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439 2Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, China 3HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL 60439. In 2011, Lin etal found that glassy carbon was converted into a new carbon allotrope with a fully sp3-bonded amorphous structure under high pressure of about 45 GPa [1]. However, the transition was reversible upon releasing pressure. Recently, Zeng etal synthesized quenchable amorphous diamond from glassy carbon with the combination of high pressure and in situ laser heating [2]. To understand the atomic structure and chemical bonding, we studied the recovered carbon materials using aberration corrected TEM and electron energy-loss spectroscopy (EELS). We confirmed that the recovered material is amorphous diamond with completely tetrahedral sp3-bonds. We first investigated the structure and chemical bonding of the starting material. Glassy carbon (Fig. 1b) consists of numerous curved graphitic layers with interlayer distances ranging from 3.5- 3.9 Å. For comparison, we also studied curved graphitic carbon and amorphous carbon with different degree of crystallinity of graphitic carbon as shown in HREM images in Fig. 1. With the aberration-corrected TEM, some fragmented curved graphene can be observed in the amorphous carbon (Fig. 1c). EELS spectra of glassy carbon show a strong pre-peak at ~285 eV, corresponding to the transitions of 1s electrons to π∗ state, as a result of its nearly 100% sp2 bonds.
    [Show full text]
  • Compressed Glassy Carbon Maintaining Graphite-Like Structure
    www.nature.com/scientificreports OPEN Compressed glassy carbon maintaining graphite-like structure with linkage formation between Received: 24 July 2018 Accepted: 1 May 2019 graphene layers Published: xx xx xxxx Yuki Shibazaki1,2, Yoshio Kono3,4 & Guoyin Shen3,5 Amorphous diamond, formed by high-pressure compression of glassy carbon, is of interests for new carbon materials with unique properties such as high compressive strength. Previous studies attributed the ultrahigh strength of the compressed glassy carbon to structural transformation from graphite-like sp2-bonded structure to diamond-like sp3-bonded structure. However, there is no direct experimental determination of the bond structure of the compressed glassy carbon, because of experimental challenges. Here we succeeded to experimentally determine pair distribution functions of a glassy carbon at ultrahigh pressures up to 49.0 GPa by utilizing our recently developed double-stage large volume cell. Our results show that the C-C-C bond angle in the glassy carbon remains close to 120°, which is the ideal angle for the sp2-bonded honey-comb structure, up to 49.0 GPa. Our data clearly indicate that the glassy carbon maintains graphite-like structure up to 49.0 GPa. In contrast, graphene interlayer distance decreases sharply with increasing pressure, approaching values of the second neighbor C-C distance above 31.4 GPa. Linkages between the graphene layers may be formed with such a short distance, but not in the form of tetrahedral sp3 bond. The unique structure of the compressed glassy carbon may be the key to the ultrahigh strength. Carbon is known to display numerous allotropes, such as graphite, diamond, fullerenes, carbon nanotubes, and glassy carbon, because of its fexibility to form chemical bonds with sp-, sp2-, and sp3-hybridizations.
    [Show full text]
  • Immobilization of Fullerene C60 at Cathodically Polarized Glassy Carbon for Generation of Thin Nucleophilic Layers and Their Carboxylation and Alkylation J
    Immobilization of fullerene C60 at cathodically polarized glassy carbon for generation of thin nucleophilic layers and their carboxylation and alkylation J. Simonet, V. Jouikov To cite this version: J. Simonet, V. Jouikov. Immobilization of fullerene C60 at cathodically polarized glassy carbon for generation of thin nucleophilic layers and their carboxylation and alkylation. Carbon, Elsevier, 2020, 156, pp.438-444. 10.1016/j.carbon.2019.09.060. hal-02367955 HAL Id: hal-02367955 https://hal-univ-rennes1.archives-ouvertes.fr/hal-02367955 Submitted on 8 Jun 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Journal Pre-proof Title page Immobilization of fullerene C60 at cathodically polarized glassy carbon for generation of thin nucleophilic layers and their carboxylation and alkylation. Jacques Simonet[a]* and Viatcheslav Jouikov[a] [a] University of Rennes 1, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226, F-35000 Rennes, France Tel: +33 (0) 22-323-6293 E-mail: [email protected] [email protected] [a] Prof. J. Simonet, Prof. V. Jouikov, Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226, F-35000 Rennes, France E-mail: [email protected] or [email protected] Journal Pre-proof Graphical Abstract Journal Pre-proof Immobilization of fullerene C60 at cathodically polarized glassy carbon for generation of thin nucleophilic layers and their carboxylation and alkylation.
    [Show full text]
  • Preparation, Characterization and Applications of Functionalized Carbon Nano-Onions
    University of Kentucky UKnowledge Theses and Dissertations--Chemistry Chemistry 2013 PREPARATION, CHARACTERIZATION AND APPLICATIONS OF FUNCTIONALIZED CARBON NANO-ONIONS Mahendra K. Sreeramoju [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Sreeramoju, Mahendra K., "PREPARATION, CHARACTERIZATION AND APPLICATIONS OF FUNCTIONALIZED CARBON NANO-ONIONS" (2013). Theses and Dissertations--Chemistry. 20. https://uknowledge.uky.edu/chemistry_etds/20 This Doctoral Dissertation is brought to you for free and open access by the Chemistry at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Chemistry by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained and attached hereto needed written permission statements(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine). I hereby grant to The University of Kentucky and its agents the non-exclusive license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless a preapproved embargo applies. I retain all other ownership rights to the copyright of my work.
    [Show full text]
  • Nanostructures of Graphite and Amorphous Carbon - Fabrication and Properties
    THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Nanostructures of Graphite and Amorphous Carbon - Fabrication and Properties Hans Fredriksson Department of Applied Physics CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2009 I Nanostructures of Graphite and Amorphous Carbon ‐ Fabrication and Properties © HANS FREDRIKSSON, 2009 ISBN 978‐91‐7385‐307‐1 Doktorsavhandlingar vid Chalmers tekniska högskola Ny serie nr 2988 ISSN 0346‐718X Department of Applied Physics Chalmers University of Technology SE‐412 96 Göteborg SWeden Telephone + 46 (0)31‐772 1000 Cover: Optical extinction spectra from amorphous carbon nanostructures With decreasing sizes and SEM images of nanostructured graphite samples With three different feature sizes. Printed at Chalmers Reproservice Göteborg, SWeden 2009 II ABSTRACT Nanoscience is a well-established research area, which concerns properties and fabrication of objects with typical dimensions on the 1-100 nanometer length scale. A central issue has been the development of techniques for fabrication and characterization of nanometer sized objects, which have contributed considerably to progress in both practical applications and fundamental research. Still, a standing challenge in nanofabrication is to further decrease the size limit and increase the precision in structure fabrication, with a simultaneous increase in reliability and cost- efficiency. Other goals are to facilitate fabrication of nanostructures in a variety of materials, with different geometries and spatial distributions. Examples of practical applications of nanofabrication are, electronic devices, nanoparticle reinforced composite materials, materials for extraction and storage of energy, sensors and biomedical applications. In this thesis, the development and application of a nanofabrication technique termed hole-mask colloidal lithography (HCL) is described. The technique is based on self- assembly of nanospheres in combination with spin coating and thin film evaporation to produce supported nanostructured masks for etch and/or deposition processes.
    [Show full text]
  • Hardness Nano-Polycrystalline Diamonds
    INDUSTRIAL MATERIALS Microstructure and Mechanical Properties of High- Hardness Nano-Polycrystalline Diamonds Hitoshi SUMIYA* and Tetsuo IRIFUNE High-purity nano-polycrystalline diamonds synthesized by direct conversion of graphite under high pressure and high temperature have extremely high hardness, no cleavage and high thermal stability. Because of these features, they have an immeasurable potential for industrial uses in applications such as cutting tools and abrasion resistance materials. In order to clarify the factors contributing to their high hardness, the microstructures and mechanical properties of nano-polycrystalline diamonds synthesized by the direct conversion of various carbon materials were investigated. The results of indentation hardness tests revealed that polycrystalline diamonds synthesized from graphite under ≧15 GPa and at 2300°C to 2500°C (consisting of fine grains 10 to 30 nm in size and crystal layers) have very high Knoop hardness (Hk ≧120 GPa), whereas polycrystalline diamonds synthesized from non-graphitic carbons under ≧15 GPa and at 1800°C to 2000°C (consisting only of single nano-grains of 5 to 10 nm) have much lower hardness (Hk = 70 to 90 GPa). The observation results of the microstructures of these nano-polycrystalline diamonds beneath the indents suggest that the existence of lamellar structure and the degree of grain bonding strength decisively influence the hardness and toughness of polycrystalline diamonds. 1. Introduction cracks or contaminants. This nano-polycrystalline dia- mond consists of extremely fine grains, and is thought Recently, the authors succeeded in synthesizing sin- to exhibit extremely high hardness due to its lack of gle-phase polycrystalline specimens of dense and super- impurities and inclusions, but the specific mechanism hard diamond by direct conversion from graphite by which it reaches high hardness has been unclear.
    [Show full text]
  • Voltammetric Sensors for the Determination of Biomolecules/Doping Agents
    VOLTAMMETRIC SENSORS FOR THE DETERMINATION OF BIOMOLECULES/DOPING AGENTS A THESIS Submitted in partial fulfilment of the requirements for the award of the degree of DOCTOR OF PHILOSOPHY in CHEMISTRY by SUNITA BISHNOI G~NTRAL Lle,~ C 2 I Sc3. 4• ACC No ................. .p çi 4 DEPARTMENT OF CHEMISTRY INDIAN INSTITUTE OF TECHNOLOGY ROORKEE ROORKEE-247 667 (INDIA) MAY, 2011 Of INDIAN INSTITUTE OF TECHNOLOGY ROORKEE ROORKEE CANDIDATE'S DECLARATION I hereby certify that the work which is being presented in the thesis entitled, "VOLTAMMETRIC SENSORS FOR THE DETERMINATION OF BIOMOLECULES/DOPING AGENTS" in partial fulfilment of the requirements for the award of the Degree of Doctor of Philosophy and submitted in the Department of Chemistry of the Indian Institute of Technology Roorkee, Roorkee is an authentic record of my own work carried out during a period from July, 2007 to May, 2011 under the supervision of Dr. R.N. Goyal, Professor, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee. The matter presented in the thesis has not been submitted by me for the award of any other degree of this or any other Institute. (SUNITA BISHNOI) This is to certify that the above statement made by the candidate is correct to the best of my knowledge. (R.N. Goyal) Supervisor Date: The Ph.D. Viva-Voce Examination of Ms. Sunita Bishnoi, Research Scholar, has been held on ....Z.a:..il :. (I................. Signature of Su sor Signature of External Examiner ct)W— 1 ABSTRACT The need of highly sensitive and selective sensing probes having enormous practical applications and significant benefits over conventional technologies attracted researchers towards nanomaterials based technologies.
    [Show full text]