简介:利用法国巴黎天文台的南锡射电望远镜对ON2西部区域OH1612MHz脉泽首次进行观测,观测结果表明,西部区域的OH1612MHz脉泽的辐射频谱为典型的单峰结构。结合模型对西部区域的OH1612MHz脉泽谱线频谱图进行分析和研究。利用薄盘模型。得到相应于ON2西部区域的OH1612MHz脉泽单峰脉泽斑的位置在r=112.5AU,Y=7.6AU,其Keplerian运动速度为Ur=10.6kg/s,V1=-9.4km/s。
简介:目的调查正畸患者上颌恒侧切牙发生锥形牙的患病状况。方法对1612例在正畸科就诊患者的病历资料进行上颌侧切牙形态研究,对不同性别和不同错胎类型的患病率进行卡方检验。结果上颌锥形侧切牙的总体患病率为7.6%,男性患病率(8.3%)与女性患病率(7.1%)之间差异无统计学意义(P〉0.05)。安氏Ⅱ类错殆畸形中锥形牙的患病率(10.1%)显著高于I类(6.1%)和Ⅲ类(6.O%)(P〈0.05)。锥形侧切牙双侧发生者占40.2%,单侧发生者占59.8%,其中右侧(35.2%)多于左侧(24.6%)。结论上颌锥形侧切牙在正畸人群中的发病率高于普通人群,其在安氏Ⅱ类错殆畸形患者中的患病率显著高于I类和Ⅲ类错胎畸形患者。
简介:铝和铬的性质有不少相似之处.它们都是两性金属,既能溶于酸又能溶于强碱;都被冷的浓硝酸钝化,其氧化物Al2O3、Cr2O3都是熔点高、硬度大的物质,其氢氧化物Al(OH)3、Cr(OH)3都是难溶于水的两性氢氧化物,既能溶于酸又能溶于强碱.本文利用Al—H2O系统的(?)—pH图及Cr—H2O系统的(?)—pH图,对铝和铬及其氢氧化物的两性进行分析.一、Al—H2O系统(?)—pH图图1为Al—H2O系统的(?)—pH图,其作法是:(?)线代表H+/H2线.根据(?)(H+/H2)=-0.0592pH-(0.0592/2)1g(P(H2))
简介:MyWife,Edna,andIweremarriedonDecember17,1939.Aweeklater,itwasalmostChristmas,andI’dspentmostofmysmallsavingsonourweddingandhoneymoon.IhadnoprospectofincomeanytimesoonbecauseIworkedforalumbercompanythatwascloseddownforthewinter.Nevertheless,EdnaandIwentshoppingforeveryoneonourlist.Itwasacoldday,butwewereyoungandenthusiastic,scamperinginandoutofstores,pickingupgiftshereandthere.Ievendropped
简介:研究了至今为止已发现的20个河外H2O超脉泽源的观测参数。多数河外H2O超脉泽源的光度在几十至几百个L⊙之内,但TXFS2226-184源的河外H2O超脉泽源光度达6100L⊙它属于射电星系类型,主要是由于其谱线轮廓较宽所造成的一种例外情况。所有20个河外H2O超脉泽源的系统速度约为几百到几千km·s^-1,16个河外H2O超脉泽源的峰值流量密度小于1Jy,但有4个河外H2O超脉泽源的峰值流量密度大于6Jy(6.2~16Jy)。通过对这些河外H2O超脉泽源的观测参数特征的分析和研究,得到这些观测参数之间的相关关系为:河外H2O超脉泽源的峰值流量密度的对数分别与系统速度的对数和距离的对数之间存在着反相关关系。而河外H2O超脉泽源的光度的对数与距离平方和峰值流量密度乘积的对数之间存在着正相关关系。
简介:ThephaseandmorphologytransformationduringthehydrothermaltreatingprocessofY2O3wasevaluatedwithX-raydiffcrcnce(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),particlesizeandspecificsurfaceareadetermination.TheresultsshowedthatthecubicY2O3didnottransferintohexagonalY(OH)3inpurewater.Therefore,purehexagonalY(OH)3withnanotubeandmicrorodmorphologieswereobtainedbyhydrothermaltreatingY2O3at150℃for12hin15mlof2mol/LNaOHsolutionwithandwith-outPVAorPEGItwassuggestedthatthecharacteristicpreferentialgrowthofY(OH)3wasattributedtothestructureanisotropyofhexahedronY(OH)3.TheadditionofPVAorPEGcouldpromotetheformingprocessofnanotubesbyselectiveadsorptionondifferentcrystalplanes,whichalteredthegrowthratealongdifferentdirectionsandresultedinthediffusionlimitofconstructingionsinthecentertopofrods.Finally,Y(OH)3:EuandY2O3:Eunanotubeswerealsosynthesizedbyusingthismethod,andtheirphotoluminescencepropertieswereevaluated.
简介:AquantummechanicalcalculationwasperformedtostudytheTranslation-Vibration(T-V)energytransferofacolinearOH+O/OD+Osystem,forwhichDelvescoordinatesandR-matrixpropagatationmethodswereappliedtoaMulius-Blintpotentialenergysurface.ThecalculatedresultoftheT-Venergytransferprobabilityshowsstrongoscillationphenomenaandthecollisiondelaytimeofthetitlesystemwasinthe10-15—10-12stimescale.Thekineticisotopeeffectwasdiscussedinthisworktoo.