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用浸渍法制备了一系列不同Mo含量的MoO3/Al2O3催化剂.测量了这些样品的正电子湮没寿命谱(PALS)与符合多普勒展宽(CDB)谱,以研究其孔洞结构以及Mo分散.正电子寿命测量结果表明,Al2O3载体中存在两种不同尺寸的孔洞.掺入MoO3之后,Mo原子主要进入Al2O3的大孔中,使孔洞体积减小.符合多普勒展宽谱结果表明,当MoO
关键词:
3/Al2O3催化剂')" href="#">MoO3/Al2O3催化剂
正电子湮没寿命谱
符合多普勒展宽
Mo 分散 相似文献
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测量了磁性纳米Fe3O4颗粒的X射线衍射谱(XRD)、正电子湮没寿命谱(PALS)和符合多普勒展宽谱(CDBS),研究了不同压力和退火温度对磁性纳米Fe3O4颗粒物相、电子结构、缺陷及电子动量分布等的影响. XRD,PALS,CDBS测量结果表明:纳米Fe3O4颗粒的缺陷浓度随压力的增加而增大,但物相和缺陷类型并未发生变化;磁性纳米Fe3O4<
关键词:
正电子
3O4')" href="#">Fe3O4
寿命谱
多普勒展宽谱 相似文献
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金红石型Ti O2是一种非常好的稀磁半导体材料,其自身的本征缺陷与室温铁磁性起源密切相关.本文利用Doppler程序在广义梯度理论(GGA)的基础上,计算了正电子在金红石型Ti O2块材中不同缺陷处的湮没寿命.主要包括自由态正电子的湮没寿命,单空位和双空位处束缚态正电子的湮没寿命.并从理论上给出了含有空位缺陷时金红石型Ti O2的符合多普勒展宽能谱. 相似文献
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测量了不同C或B含量经不同烧结温度制备的Si基半导体、单晶Si、单晶SiO2、石墨和纯多晶B样品的正电子寿命谱和符合正电子湮没辐射Doppler展宽谱。结果表明,石墨的商谱谱峰最高,SiO2的谱峰次之,B的谱峰最低。随着B,C和O原子序数的增加,与正电子湮没的电子动量增加。含20%的C和含100ppm的B的样品的商谱的谱峰最高;含100ppm的B的样品的谱峰次之;含1ppm的B的样品的谱峰最低。随着烧结温度的升高,含100ppm的B的Si基半导体样品的商谱降低,正电子寿命增长,缺陷开空间和浓度升高。 相似文献
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Summary We report the measurements of the3
D(3s4d)-3
P(3s3p)3
D(3s5d)-3
P(3s3p), and3
P(3p
2)-3
P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between24Mg and26Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing
in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of
theI
2 transitions used as a reference and by the precision in the knowledge of the related wavelengths. 相似文献
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The systematic application of band contour techniques to account for most of the observed features of the ir spectra of s-triazine and s-triazine-d3 have been made as well as a critique as to the limitations of such methods. The experimental and computer methods used to study the gas phase infrared band contours of s-triazine and s-triazine-d3 are out-lined. Contours of the five E′ fundamentals of s-triazine have been recorded under moderate resolution and analyzed to give the Coriolis constants , i = 6–10. The effects of l-resonance are very apparent for ν8 and ν9, in the form of holes in the Q branches of these bands. Under the highest resolution available, ν6 and ν10 also show l-resonance effects. Values of the l-doubling constants were obtained for these four fundamentals. One of the parallel A2″ fundamentals of C3H3N3 (ν12) has also been studied. It lies close to ν10(E′) and an A × E type of second-order Coriolis resonance may be the cause of the intensity enhancement observed in the inner wings of the ν12 and ν10 bands. Hot bands of the type (νi + nν14 ? nν14) have been observed in the contours of ν8, ν10, and ν12. This is felt to be responsible for the large difference between our observed zeta sum (?1.30) and the theoretical sum (?1.00).The gas phase infrared band contours of the five E′ and 2A2″ fundamentals of C3N3D3 have also been recorded under moderate resolution. From P-R separations and by computer simulation of the contours, values of the Coriolis constants have been obtained for the E′ modes. The effects of l-resonance have been observed for ν8(E′) and ν10(E′) and values of the l-doubling constants have been estimated. An extensive series of hot bands of the type (ν12 + nν14 ? nν14) has been observed in the contour of the ν12 (A2″) fundamental. The mass effect on the Coriolis constants has been discussed.Infrared band contours of the overtone 2ν7 and seven degenerate E′ combination bands of C3N3H3 have been recorded under moderate resolution. Analysis of these contours using the P-R separation method and computer simulation of the contours has given values of for these bands. Fermi resonance between 2ν7 and ν6 has been analyzed. The importance of considering both the observed contour as well as the observed frequency when assigning higher tone bands is illustrated. 相似文献
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P. A. Markovin V. V. Lemanov M. E. Guzhva P. P. Syrnikov T. A. Shaplygina 《Physics of the Solid State》2014,56(5):989-995
The temperature dependences of the dielectric constant and dielectric hysteresis loops in ceramic samples of (1 ? x)SrTiO3?x KNbO3 and (1 ? x)SrTiO3?x KTaO3 (0 ≤ x ≤ 0.3) solid solutions prepared using different heat treatments have been investigated. Phase diagrams of the studied solid solutions have been constructed in the T-x coordinates. It has been shown that, after quenching of samples (spontaneous cooling at room temperature after long-term heating at the sintering temperature of the ceramic samples), the temperature of the induced phase transition increases because of the weakening of random electric fields associated with nonisovalent impurities due to their “frozen” nonequilibrium redistribution. For small concentrations x, strong dielectric relaxation is observed in the temperature range of 150–250 K. A model of relaxing centers, which is based on the local charge compensation of heterovalent impurities, has been proposed. 相似文献
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The infrared spectra of ammonia-borane, BH3NH3, and two of its deuterated isotropic species, BD3ND3 and BH3ND3, isolated in argon matrix at liquid hydrogen temperature have been measured. Well resolved bands for these three isotopic species have been observed for all the fundamentals. A complete frequency assignment based on C3v molecular symmetry has been made. A set of force constants have been calculated from the data for the two isotopes BH3NH3 and BD3ND3 using a valence force field. The agreement between experiment and frequencies calculated from these force constants for the mixed isotopic species, BH3ND3, substantiates the present assignment. 相似文献
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JETP Letters - Films of CH3NH3PbI3 organometallic perovskite, which is currently considered as a promising basic material for new-generation solar cells, as well as films containing CsPbI3... 相似文献
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Knorr K. Loidl A. Stühn B. Buevoz J. L. 《Zeitschrift für Physik B Condensed Matter》1981,41(4):315-320
Neutron diffraction experiments have been carried out on the magnetically ordered phases of ErPb3, HoPb3, ErTl3 and HoTl3. The magnetic moments were found to be sinusoidally modulated with a propagation vector of (0, 0.2, 0.5) for the Pb-compounds and (0.38, 0.38, 0.16) for the Tl-compounds.Work supported by the Bundesministerium für Forschung und Technologie 相似文献
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(LaO)3BO3中Eu^3+和Sm^3+的光致发光 总被引:4,自引:2,他引:2
研究了紫外光激发下,(LaO)3BO3基质中Eu^3+和Sm^3+的光谱性质,Eu^3+和Sm^3+的电荷迁移激发带及发光强度随组成和结构变化的规律性,并探讨了Eu^3+和Sm^3+自身浓度猝灭的机理。 相似文献