简介：WehavestudiedtheangularmagnetoresistanceofironpnictidesBaFe2-xNixAs2,whichshowsclear180degreeperiodicityasfittedbyacosinefunction.Inthex=0.065sample,thephaseofthetwo-foldsymmetrychanges90degreesabovethetetragonal-to-orthorhombicstructuraltransitiontemperatureTs.Sincethephaseatlowtemperatureisassociatedwiththerotationoforthorhombicdomainsbymagneticfield,weshowthatevenvacuumgreasecanpushthepresenceoforthorhombicdomainsattemperaturesmuchhigherthanTs.Ourresultssuggestthatresidualstressmayhavesignificanteffectsinstudyingthenematicordersanditsfluctuationsinironpnictides.

简介：ReactionsofCuSCNwithtetramethylthiuramdisulfideinCH3CNinthepresenceofstyreneandN,N,N',N',N'-pentamethyldiethylenetriaminegaverisetoanewcopper(Ⅰ)complexofN,N'-dimethyldithio-cabamate{[Cu(S2CNMe2)]2}n.ThetitlecompoundcrystallizedinthetriclinicP-1spacegroupwithlatticeparametersα=0.7610(4)nm,b=0.8911(4)nm,c=0.9268(5)nm,α=68.66(1)°,β=83.88(2)°,γ=79.31(2)°,V=0.5748(5)nm^3,Z=2.Thecompoundhasaunique1DchainstructurecomposedofCuSCSCuSCSeight-memberedringsandapairofCu-Sbonds,thestructureofwhichhasbeendeterminedbysingle-crystalX-raycrystallography.Theisolationofthiscompoundmayprovidesomehelpfulinformationforthecauseoftheinductionperiodsofthereverseatomtransferradicalpolymerization.

简介：Wereporteddiversesolitonoperationsinathulium/holmium-dopedfiberlaserbytakingadvantageofataperedfiber-basedtopologicalinsulator（TI）Bi2Te3saturableabsorber（SA）.TheSAhadanonsaturablelossof53.5%andamodulationdepthof9.8%.Stablefundamentallymode-lockedsolitonsat1909.5nmwithdistinctKellysidebandsontheoutputspectrum,apulserepetitionrateof21.5MHz,andameasuredpulsewidthof1.26pswereobservedinthework.Byincreasingthepumppower,bothbunchedsolitonswithsolitonnumberupto15andharmonicallymode-lockedsolitonswithharmonicorderupto10wereobtained.Toourknowledge,thisisthefirstreportofbothbunchedsolitonsandharmonicallymode-lockedsolitonsinafiberlaserat2μmregionincorporatedwithTIs.

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简介：Mode-andpolarization-divisionmultiplexingoffernewdimensionstoincreasethetransmissioncapacityofopticalcommunications.Selectiveswitchesarekeycomponentsinreconfigurableopticalnetworknodes.Anon-chipsilicon2×2mode-andpolarization-selectiveswitchthatcanroutefourdatachannelsontwomodesandtwopolarizationssimultaneouslyisproposedandexperimentallydemonstratedforthefirsttime,tothebestofourknowledge.Theoverallinsertionlossesarelowerthan8.6dB.Toreducetheinter-modalcrosstalk,polarizationbeamsplittersareaddedtofiltertheundesiredpolarizationsormodes.Themeasuredinter-modalandintra-modalcrosstalkvaluesarebelow-23.2and-22.8dBforallthechannels,respectively.

简介：TheAlkalineThermalTreatment（ATT）ofbiomassisoneofthefewbiomassconversionprocessesthathasapotentialforBECCS（bio-energywithcarboncaptureandstorage）.Combiningin-situcarboncapturewithcreatesacarbon-neutralprocessthathasthepotentialtobecarbon-negative.Thisstudyhasshownthattheconversionofcellulosetosuppressedcanbeachievedthroughthereformingofgaseousintermediatesinafixedbedof10%Ni/ZrO2.Reformingoccursatlowtemperatures≤773K,whichcouldallowforimprovedsustainability.

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简介：利用MP2和mPWPW91方法,在6-311G＊＊和6-311＋＋G＊＊基组水平上研究了RDX分别与硝基、氨基和迭氮基取代的氮杂杯[2]-间-芳烃[2]三嗪和氮杂杯[2]-对-芳烃[2]三嗪形成的分子间氢键相互作用,并借助自然键轨道（NBO）和分子中的原子（AIM）理论揭示了氢键的本质.结果表明,氮杂杯[2]-间-芳烃[2]三嗪复合物中氢键主要发生在RDX与三嗪环及其取代基之间;氮杂杯[2]-对-芳烃[2]三嗪复合物中氢键主要发生在RDX与杯芳烃环及其取代基之间.分子间相互作用能在-18.82--40.62kJ/mol之间;经基组叠加误差（BSSE）校正后,相互作用能顺序为e〉f≈b〉a〉c〉d和e′〉b′〉f′〉a′〉d′〉c′.两类复合物中,氨基取代的复合物分子间氢键强于硝基或叠氮基复合物分子间氢键,氨基氮杂杯[2]-对-芳烃[2]三嗪与RDX形成的氢键最强,有望作为降低火炸药感度、进行火炸药废水处理的候选物.为获得稳定性较强的RDX-氨基氮杂杯芳烃超分子炸药,应该选取介电常数较大的溶剂.

简介：Ahighlyeffcientandgeneralmethodforthesynthesisofpolyfunctionalized4H-pyransisestablishedthroughaone-potmulticomponentcyclocondensationofaromaticaldehydeswithCHacids,malononitrileandethylacetoacetateusingnanosilicasupportedtin(II)chlorideasacatalyst.InthismethodSnCl2/nanoSiO2wasusedasgreenandreusablecatalyst.Excellentyields,shortreactiontimes,simpleworkup,andinexpensivenessandcommerciallyavailabilityofthecatalystaretheadvantagesofthismethod.

简介：证明了指数型超椭圆方程x^2=p^2m-p^m＋n＋1无解（x，p，m，n），其中x，m，n∈N^＋，m〉n〉1，p∈P．上述结果部分解决了组合论中关于可逆Abel差集的Ma猜想．

简介：Rare-earthcompoundsolidsuperacidSO42-/TiO2/La3+wasprepared.Itscatalyticactivitywasexaminedunderdifferentsyntheticconditionsfortheesterificationofpropanoicacidandn-butylalcoholasprobingreaction.Theoptimumconditionswerealsofound,whichwerethepH=8,thedepositingtimewas24h,themassfractionofLa(NO3)3usedinsolidsuperacidwas5%,theconcentrationofH2SO4was1.25mol/L,thesoakingtimeinH2SO4was16handthecalciningtemperaturewas500°C.TheethyloleatewassynthesizedfromoleicacidandethanolinthepresenceofSO42-/TiO2/La3+.Theoptimumreactionconditionswereobtainedwhichwerethereactiontimewas6h,molarratioofoleicacidtoethanolwas1:4andthemassfractionofcatalystwas4%.

简介：MakinguseoftheZ2×Z2symmetry,wecouldstudythestructurenearmultipleS-treakingturningpoints.Inparticular,weshowthatthereexisttwokindsofsingularpointpaththroughdoubleSbreakingturningpointsandtripleSbieakingturningpoints,onetsquadraticturningporntpathandoneisquadraticpitchforkbifurcationpointpath.SomesimpleregularextendedsystemstocornputedoubleandtripleS-breakingturningpointsareproposed.Numericalexamplesarealsogreen

简介：AgraphGiscalledchromatic-choosableifitschoicenumberisequaltoitschromaticnumber,namelych(G)=χ(G).Ohba’sconjecturestatesthateverygraphGwith2χ(G)+1orfewerverticesischromaticchoosable.ItisclearthatOhba’sconjectureistrueifandonlyifitistrueforcompletemultipartitegraphs.Recently,Kostochka,StiebitzandWoodallshowedthatOhba’sconjectureholdsforcompletemultipartitegraphswithpartitesizeatmostfive.Butthecompletemultipartitegraphswithnorestrictionontheirpartitesize,forwhichOhba’sconjecturehasbeenverifiedarenothingmorethanthegraphsKt+3,2*(k-t-1),1*tbyEnotomoetal.,andKt+2,3,2*(k-t-2),1*tfort≤4byShenetal..Inthispaper,usingtheconceptoff-choosable(orL0-size-choosable)ofgraphs,weshowthatOhba’sconjectureisalsotrueforthegraphsKt+2,3,2*(k-t-2),1*twhent≥5.Thus,Ohba’sconjectureistrueforgraphsKt+2,3,2*(k-t-2),1*tforallintegerst≥1.

简介：TheapplicationofLanthanumBromide(LaBr3)detectorsprovidesauniqueopportunitytomeasurelifetimeofexcitedstatesinpicosecond-nanosecondregion.Reducingthebackgroundisofcriticalimportancetogetpreciseresults.Forsomeexcitedstatesfeedingfromisomerswithlifetimelongerthan1μs,itcanbeachievedbytheSpectrometerforHeavyAtomandNuclearStructure(SHANS)[1].143Eunucleiwerepopulatedviathe123Sb(24Mg,4n)fusion-evaporationreaction.Mostoftheevaporationresiduesatgroundstateorlong-livedisomersweretransferredtodetectionterminalafteraflightofabout1.4μsinSHANS.Inthecaseof143Eu,threetransitionshavebeenobserved(Fig.1).

简介：TiO2nanoparticlesweresynthesizedbyahomogeneouscontrolledprecipitationmethodusingindustrialtitaniumsulfate(Ti(SO4)2).TheobtainedpowderswerecharacterizedbyX-raydiffraction(XRD),transmissionelectronmicroscope(TEM),Fouriertransforminfraredspectroscopy(FTIR)andICPplasmaspectrometer.EDTAwasusedascomplexingagenttoimprovethepurityandtheformationofTiO2nanoparticles.Experimentalresultsindicatedthatthehigh-purityTiO2nanoparticleswere20nminmeansizeandnearlymonodispersed.

简介：Inthispaperwereportachemicaloscillationcatalyzedby[Ni(Me2[14]1,3-dieneN4)]2+(Me2[14]l,3-dieneN4denotes2,3-dimethyl-l,4,8,ll-tetraazacyclotetradeca-1,3-diene)inBrO3--pyruvicacid-H2SO4system.Thedomainoftheexistenceoftheoscillationwasobtained.Theeffectsofinitialconcentrationofthecomponentsontheoscillationwerestudied.Thefeaturesoftheoscillationsweredescribedindetail.WealsoexaminedtheeffectsofAg+,Hg2+,CCl4,freeradicalinhibitors,etc.ontheosillations.

简介：QuantumdynamicscalculationsforthetitlereactionH(2S)+S2(X3-Σg)→SH(X2Π)+S(3P)areperformedbyusingagloballyaccuratedoublemany-bodyexpansionpotentialenergysurface[J.Phys.Chem.A1155274(2011)].TheChebyshevrealwavepacketpropagationmethodisemployedtoobtainthedynamicalinformation,suchasreactionprobability,initialstate-specifiedintegralcrosssection,andthermalrateconstant.Itisfoundnotonlythatthereisareactionthresholdnear0.7eVinbothreactionprobabilitiesandintegralcrosssectioncurves,butalsothatboththeprobabilityandcrosssectionincreasefirstlyandthendecreaseasthecollisionenergyincreases.Theexistenceoftheresonancestructureinboththeprobabilityandcrosssectioncurvesisascribedtothedeeppotentialwell.Thecalculationoftherateconstantrevealsthatthereactionoccurringonthepotentialenergysurfaceoftheground-stateHS2isslowtotakeplace.