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排序方式: 共有559条查询结果,搜索用时 15 毫秒
1.
《Journal of Crystal Growth》2006,286(2):400-406
Radiofrequency (RF) nitrogen plasma sources are commonly employed in the growth of group III-nitrides by molecular beam epitaxy and reactive evaporation. These sources produce atomic nitrogen and excited molecules (N2*). In this work the relative flux of these two species produced by an RF source was studied by emission spectroscopy as a function of power, pressure, and argon dilution. Polycrystalline indium nitride thin films were synthesized under the same conditions. It was found that argon dilution had a strong influence on the production of active nitrogen, with maximum fluxes obtained around ∼40% N2. Film properties, as measured by X-ray diffraction, atomic force microscopy and Hall effect, were also optimized at this condition. It was observed that the Hall mobility scaled with the sum of N and N2* emission, suggesting that both species may be beneficial for InN growth. 相似文献
2.
3.
T. N. Srivastava R. C. Srivastava Mala Singh 《Journal of organometallic chemistry》1978,160(2):449-454
Iodine monohalides (ICl, IBr), cyanogen halides (CNBr, CNI) and thiocyanogen (SCN)2 add oxidatively to diaryltellurium(II), R2Te (R = Ph, p-Ch3OC6H4) under mild conditions (
°C). The resulting organotellurium(IV) derivatives react metathetically with silver pseudohalides to yield several new diaryltellurium(IV) pseudohalide derivatives. 相似文献
4.
Kinetics of oxidation of lactose, maltose, cellobiose and melibiose has been studied by hexacyanoferrate(III) in the presence of ammonia. A general mechanism involving the formation of intermediate enodiol anion has been suggested. The effects of dielectric constant and salts have been studied in detail. The oxidation products have been characterised by descending paper chromatography. Compensation effects have been observed. 相似文献
5.
合成了七(2,3-二-O-乙酰基-6-O-叔丁基二甲基硅烷基)-β-环糊精,并采用静态法成功地将其涂渍到弹性石英毛细管柱上。研究了其气相色谱分离性能,发现此固定相涂渍性好,柱效较高,热稳定性好,对卤代芳烃异构体以及难分离的二取代苯的位置异构体具有良好的分离能力。 相似文献
6.
Pentacoordinate complex cations of the general formula [(C6F5)2SbL3]3+ stabilized as solid salts in combination with tetraphenylborate (BPh4), tetrafluorobroate (BF4) anions, where L=DMSO, Ph3AsO, PyO, DMF, α-, β- and γ-picoline have been isolated. The newly formed complexes were characterized by elemental analysis, molar conductance measurements, solid-state IR and and NMR. From these results, a five-fold coordination around antimony was required. 相似文献
7.
8.
CrOx/ SBA-15介孔催化剂上丙烷在二氧化碳气氛中脱氢反应的研究 总被引:2,自引:0,他引:2
The structure and catalytic properties based on Chromium Oxide supported on mesoporous SBA-15 for oxidative dehydrogenation of propane by CO2 have been studied by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and propane pulsing experiments in the absence of gas-phase O2. It has been shown that propane conversion and propene yield increase with Cr loadings. The propane conversion and propene yield on CrOx(Cr: 10wt%)/SBA-15 catalyst for oxidative dehydrogenation of propane by CO2 at 550 ℃ reach 24.8% and 21.8%, respectively .The results of ESR, UV-Vis DRS and propane pulsing experiments indicate that CrⅢ in the CrOx/ SBA-15 catalyst is the main active species in oxidative dehydrogenation of propane by CO2 and CrⅥ, CrⅤ is inactive in dehydrogenation. 相似文献
9.
S. Parveen S. Singh D. Shukla M. Yasmin M. Gupta J. P. Shukla 《Journal of solution chemistry》2012,41(1):156-172
Ultrasonic velocity, density, refractive index and viscosity of binary mixtures of aniline with acetic acid (AA) and propionic
acid (PA) have been measured at 293.15, 303.15 and 313.15 K over the entire composition range. Further, the specific heat
ratio, heat capacity, effective Debye temperature and pseudo-Gruensisen parameter and non-linearity parameter have been evaluated
using ultrasonic absorption data. The deviation in isentropic compressibility, excess molar volume, excess intermolecular
free length, deviation in molar refraction, deviation in viscosity, relaxation time, enthalpy, entropy and Gibbs energy of
activation have been calculated from the experimental data and fitted with the Redlich-Kister polynomial equation. A comparative
study has also been made between experimental and theoretically calculated values of densities using the HBT and Rackett density
models. Mixing rules for the prediction of refractive index, e.g. Lorentz-Lorenz (L-L), Eykmen (Eyk), Weiner (W), Heller (H),
Gladstone-Dale (G-D), Arago-Biot (A-B) and Newton (N) have been applied to these binary mixtures. 相似文献
10.
《Tetrahedron letters》2014,55(52):7190-7193
An iron-catalyzed coupling reaction of methylarenes with thiols leading to thioesters has been developed. The reactions were carried out in water with tert-butyl hydroperoxide (TBHP) as the oxidant and polyoxyethanyl α-tocopheryl sebacate (PTS) as the surfactant. The reaction medium is compatible with a series of functional groups and can be reused. 相似文献