简介：NanosizedGa-containingZSM-5zeoliteswerepreparedviaisomorphoussubstitutionandimpregnationfollowedbycharacterizedusingvarioustechniques.Thecatalyticperformanceofthezeolitesforthearomatizationof1-hexenewasinvestigated.TheresultsindicatethatisomorphoussubstitutionpromotestheincorporationofGaheteroatomsintotheframeworkalongwiththeformationofextra-frameworkGaO+species（[GaO+]a）thathavestrongerinteractionswiththenegativepotentialoftheframework.Inaddition,basedonthePy-IRresultsandcatalyticperformance,the[GaO+]aspecieswithstrongerLewisacidsitesproducedabettersynergismwithmoderateBr?nstedacidsitesandthusimprovedtheselectivitytoaromaticcompounds.However,theimpregnationresultsintheformationofGa2O3phaseandsmallamountsofGaO+speciesthataremainlylocatedontheexternalsurface（[GaO+]b）,whichcontributetoweakerLewisacidsitesduetoweakerinteractionswiththezeoliteframework.During1-hexenearomatization,thenanosizedGaisomorphouslysubstitutedZSM-5zeolitesamples（Gax-NZ5）exhibitedbettercatalyticperformancecomparedtotheimpregnatedsamples,andthehighestaromaticyield（i.e.,65.4wt%）wasachievedovertheGa4.2-NZ5sample,whichcontainedwiththehighestGacontent.

简介：Weinvestigateeffectsofannealingonmagneticpropertiesofathick(Ga,Mn)Aslayer,andfindadramaticincreaseoftheCurietemperaturefrom65to115Kbypostgrowthannealingfora500-nm(Ga,Mn)Aslayer.AugerelectronspectroscopymeasurementssuggestthattheincreaseoftheCurietemperatureismainlyduetodiffusionofMninterstitialtothefreesurface.Thedouble-crystalx-raydiffractionpatternsshowthatthelatticeconstantof(Ga,Mn)Asdecreaseswithincreasingannealingtemperature.Asaresult,theannealinginducedreductionofthelatticeconstantismainlyattributedtoremovalofMninterstitial.

简介：Wereportthestudyofalowtemperatureclusterglassstatein5%Mn-dopedUGa3heavyfermioncompound.Thiscompoundtransformsfromaparamagneticstatetoaspin-clusterglassstate,whichisconfirmedbymeasuringthedcsusceptibilityandmagnetization.Theacsusceptibilityexhibitsafrequency-dependentpeakaroundTf,whichprovidesdirectevidenceoftheclusterglassstate.Byanalyzingthefield-dependentmagnetizationandfrequency-dependentacsusceptibilityindetail,wededucethatthiscompoundformsaspin-clusterglassstatebelowTf.

简介：Ni/SiO2andbimetallicNixGa/SiO2catalystswithdifferentNi/Gaatomicratios(x=10~2)wereinvestigatedfortheselectivehydrogenationofacetylene.ItwasfoundthatNixGa/SiO2showedhigherselectivitytoethylenethanNi/SiO2.ThisisattributedtotheformationNi-GaalloyandNi3Gaintermetalliccompound(IMC)wheretherewasachargetransferfromGatoNi,whichisfavorableforreducingtheadsorptionstrengthandamountofethyleneonNiatoms.Asaresult,theover-hydrogenation,theC–Cbondhydrogenolysisandthepolymerizationweresuppressed,andsubsequentlytheselectivitytoethylenewasenhanced.WiththedecreaseofNi/Gaatomicratio,theactivityandstabilityoftheNixGa/SiO2catalystsincreasedfirstandthendecreased,whiletheethyleneselectivitytendedtoincrease.Ni5Ga/SiO2exhibitedthebestperformance.Undertheconditionsof180°C,0.1MPa,andareactant(1.0vol%acetylene,5.0vol%H2and94vol%N2)withthespacevelocityof36,000mLh-1g-1,theacetyleneconversionmaintainedat100%onNi5Ga/SiO2during120htimeonstreamandtheselectivitytoethylenewas75%~81%afterreactionfor68h.ItwasalsofoundthattheformationofNi-GaalloyandNi3GaIMCsuppressedtheincorporationofcarbontoformNiCx,subsequentlyenhancingthecatalyststability.Additionally,withincreasingtheGacontent,thecatalystacidamountandstrengthtendedtoincrease,whichpromotedthepolymerizationandcarbondepositionandsothecatalystdeactivation.

简介：Grapheneanditsderivativeshaveattractedtremendousresearchinterestbecauseoftheiruniquecompositionandphysicochemicalproperties[1??3].However,thepotentialbiologicaltoxicityofGQDshasbecomeahealthriskbecauseoftheirinherentchemicalcompositionandnanoscaleproperties[4].Zebrafish(Daniorerio)isoneofthemostpromisinginvivomodelsystemsfortoxicitystudies[5].

简介：Inthispaper,theconductionband-edgenon-parabolicity(NP)andthecircularcross-sectionradiuseffectsonhydrogenicshallow-donorimpurityground-statebindingenergyinzinc-blende(ZB)InGaN/GaNcylindricalQWWsarereported.Thefinitepotentialbarrierbetween(In,Ga)NwellandGaNenvironmentisconsidered.Twomodelsoftheconductionband-edgenon-parabolicityaretakingintoaccount.Thevariationalapproachisusedwithintheframeworkofsinglebandeffective-massapproximationwithone-parametric1S-hydrogenictrialwave-function.ItisfoundthatNPeffectismorepronouncedinthewireofradiusequaltoeffectiveBohrradiusthaninlargeandnarrowwires.Moreover,thebindingenergypeakshiftstonarrowwireunderNPeffect.Agoodagreementisshowncomparedtothefindingsresults.

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简介：AmassofGaNnanowireshasbeensuccessfullysynthesizedonSi(111)substratesbymagnetronsputteringthroughammoniatingGa2O3/Cofilmsat950C.X-raydiffraction,scanningelectronmicroscopy,highresolutiontransmissionelectronmicroscopeandFouriertransformedinfraredspectraareusedtocharacterizethesamples.Theresultsdemonstratethatthenanowiresareofsingle-crystalGaNwithahexagonalwurtzitestructureandpossessrelativelysmoothsurfaces.ThegrowthmechanismofGaNnanowiresisalsodiscussed.更多还原

简介：利用同步辐射对天然金刚石晶体进行了形貌学研究，在近完事晶体内观察到晶体以平行{100}生长为主的正常生长，而不是前人所常见的平行{111}生长。生长带方向平行于（100）、（100）和（010）、（010）。生长带分布在偏离晶体中心的曲面内。由生长带的分布与形态可以观察到晶体不同晶面的生长速度具有明显差异。

简介：首先介绍了非线性聚集生长计算机模型与生长规则和非线性聚集生长的实验原理与装置,然后阐述了计算凝聚物分形维数的计算机模拟方法和实验方法,最后论述了非线性聚集生长理论在大气颗粒物、薄膜生长方面的应用。

简介：采用固一液一固（SLS）生长机制，研究常压下金催化硅纳米线的制备方法。实验中将硅基Au薄膜在氩氢气中退火，退火温度为1050℃和1080℃，退火完成后在扫描电镜下观察硅片表面的形貌变化，分析不同退火温度、通气量和金膜厚度下的实验结果，并在此基础上进一步讨论了各变量对硅纳米线的生长影响及其机理。

简介：利用室温光致荧光谱（PL）研究金属有机物化学气相沉积（MOCVD）方法中温度参数对InP衬底上生长In0.53Ga0.47As/InP量子阱材料质量的影响.通过两组实验分别研究并分析了生长温度对In0.53Ga0.47As层和InP层材料质量的影响,得到了In0.53Ga0.47As层和InP层最佳生长温度分别为650℃和600℃.利用优化条件制备In0.53Ga0.47As/InP基PIN型探测器,得到器件的暗电流较优化前小2个数量级.

简介：分形理论是现代非线性科学的一个重要分支,近年来发展越来越快,应用研究也越来越广泛。本文简要介绍了分形的基本理论及其在聚集生长研究中的应用,最后展望了分形理论的应用前景及其发展前景。

简介：初中物理总复习时教师在进行教学设计时既要依据教材又不拘泥于教材,对相关联的知识进行整合,结合学生的认知水平渐进性和累积性地构建相应的知识体系.复习课应彻底转变观念,变教为导,变学为思,循循善诱,科学探究,优化教学结构,充分发挥学生与教师的群体智慧,善于抓住课堂教学的生成点,让课堂教学充满创新活力,充分提升物理复习课的课堂价值.

简介：由中子辐照引起的(n，α)反应会在核反应堆材料中残留—些氦原子。氦为惰性元素，不与其它原子结合，在材料中的溶解度极低，而且原子半径小，因此很容易在材料中迁移。氦原子首先向晶界、位错等缺陷处聚集而形成气泡，氦泡的形成使系统的总能量降低。小的氦泡又通过热运动而融合为更大的氦泡。氦泡的存在对材料性能有相当大的影响，例如它会使材料的脆性增加，严重制约了核反应堆的使用寿命。因此，金属材料中的氦泡生长问题一直受到人们的关注。

简介：在超球坐标中,用类氢波函数基展开来计算电子偶素负离子(PS~-)系统的基态能量,然后用基态波函数计算体系的形状密度,从而确定基态的几何结构。

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简介：我们可以热爱各种各样的物质，这里总是乐趣无穷。

简介：相态变化主要有物理转变和化学反应两类。物理转变包括结晶／熔融、液晶转变等相转变、玻璃化转变；化学反应包括聚合、固化、交联、氧化和分解等。由于氟聚合物的使用环境温度与其的玻璃化转变温度比较接近，笔者主要借助DSC热分析仪、X射线衍射仪、红外原位反应池、高温高压反应池等仪器研究了氟聚合物在相态转化过程中的相关物理性能变化，探讨了相态转变时分子链锻是否会发生变化。

简介：以DLA模型为基础,模拟研究了粒子运动区域和粒子源距离的大小对非对称性聚集生长产生的影响。发现粒子随机运动区域和粒子源距离的大小对局部区域聚集生长产生重大的影响。