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51.
Seebauer EG Dev K Jung MY Vaidyanathan R Kwok CT Ager JW Haller EE Braatz RD 《Physical review letters》2006,97(5):055503
The technologically useful properties of a crystalline solid depend upon the concentration of defects it contains. Here we show that defect concentrations as deep as 0.5 microm within a semiconductor can be profoundly influenced by gas adsorption. Self-diffusion rates within silicon show that nitrogen atoms adsorbed at less than 1% of a monolayer lead to defect concentrations that vary controllably over several orders of magnitude. The results show that previous measurements of diffusion and defect thermodynamics in semiconductors may have suffered from neglect of adsorption effects. 相似文献
52.
53.
Hesitant fuzzy sets are considered to be the way to characterize vague phenomenon. Their study has opened a new area of research and applications. Set operations on them lead to a number of properties of these sets which are not evident in classical (crisp) sets make the area mathematically also very productive. Since these sets are defined in terms of functions and set of functions, which is not the case when the sets are crisp, it is possible to define several set operations. Such a study enriches the use of these sets. In this paper, four new operations are envisaged, defined and taken up to study a score of new identities on hesitant fuzzy sets. 相似文献
54.
The binary mixture of 4-n-pentyl phenyl 4-n′-hexyloxy benzoate (ME6O.5) and p-cyanophenyl trans-4-pentyl cyclohexane carboxylate (CPPCC) shows the presence of induced Smectic Ad phase. In the present work the phase diagram as well as static dielectric permittivity measurements of different mixtures throughout the composition range, are reported. The observed variation of dielectric anisotropy with molar concentration in the nematic and smectic phases is explained, assuming the formation of both homo- and hetero-dimers in the mixture. 相似文献
55.
Kazuto Takaishi Bikash Dev Nath Yuya Yamada Hiroyasu Kosugi Tadashi Ema 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):10089-10093
Unique self‐assembled macrocyclic multinuclear ZnII and NiII complexes with binaphthyl‐bipyridyl ligands (L) were synthesized. X‐ray analysis revealed that these complexes consisted of an outer ring (Zn3L3 or Ni3L3) and an inner core (Zn2 or Ni). In the ZnII complex, the inner Zn2 part rotated rapidly inside the outer ring in solution on an NMR timescale. These complexes exhibited dual catalytic activities for CO2 fixations: synthesis of cyclic carbonates from epoxides and CO2 and temperature‐switched N‐formylation/N‐methylation of amines with CO2 and hydrosilane. 相似文献
56.
Dev Raj Chopra Justin Seth Pearson Darius Durant Ritesh Bhakta Anil R. Chourasia 《Surface and interface analysis : SIA》2019,51(2):246-253
The Ti/CuO interface has been studied by the techniques of X-ray photoelectron spectroscopy and atomic force microscopy. Thin films of titanium were deposited on a CuO substrate at room temperature by the e-beam technique. The photoelectron spectra of titanium and copper were found to exhibit significant chemical interaction at the interface. The titanium overlayer was observed to get oxidized to TiO2, while the CuO was observed to get reduced to elemental copper. This chemical interaction was observed to occur until a thickness of 7 nm of the titanium overlayer. For thicknesses greater than this value, the presence of unreacted titanium in the sample was detected. Barrier characteristics at the Ti/CuO interface were also carried out for substrate temperatures of 300°C, 400°C, 500°C, and 600°C as a function of the titanium overlayer thickness. A linear trend in the barrier thickness of the overlayer was observed between 400°C and 600°C substrate temperatures. The atomic force microscopy micrographs of the unannealed samples depicted layer-by-layer growth of elemental titanium on copper. At the Ti/CuO interface in such samples, the micrographs exhibited island formation of TiO2 corresponding to the Volmer-Weber growth model. This formation has been interpreted as the relaxation in the strain energy. The percentage coverage of the underlying substrate by the TiO2 islands showed a linear trend for the thicknesses of the titanium overlayer investigated. The average size of these islands also showed a linear trend as a function of the thickness of the overlayer. 相似文献
57.
Phytochemical investigation of Cissus quadrangularis stems led to the isolation of one new phenolic glycoside (1) and two new lignan glycosides (7 &; 8) along with twelve known compounds (2–6 &; 9–15). Their chemical structures were determined on the basis of extensive spectroscopic analysis using 1D, 2D NMR, and mass spectrometric analysis. Among the known compounds, 4–6, 9 and 12 were isolated for the first time from the genus Cissus whereas compounds 10, 11 and 13 for the first time from this plant. 相似文献
58.
Cation-vacancy induced intrinsic magnetism in GaN and BN is investigated by employing density-functional theory based electronic structure methods. The strong localization of defect states favors spontaneous spin polarization and local moment formation. A neutral cation vacancy in GaN or BN leads to the formation of a net moment of 3 muB with a spin-polarization energy of about 0.5 eV at the low density limit. The extended tails of defect wave functions, on the other hand, mediate surprisingly long-range magnetic interactions between the defect-induced moments. This duality of defect states suggests the existence of defect-induced or mediated collective magnetism in these otherwise nonmagnetic sp systems. 相似文献
59.
Dev Raj Alok Kumar Rohit Kumar Singh Abhishek Singh Bhadouria A.S.K. Sinha Deepak Dwivedi 《Current Opinion in Electrochemistry》2022
As the application of electrocatalyst continues to expand, envisaging the hidden mechanisms occurring at various length scale affecting the catalytic efficiency became important. To enhance the stability of electrocatalyst and reduce the cost, it is of paramount importance to reveal the active site's dynamics (using in situ techniques for getting the real-time information) which directly affect the reactions such as oxygen evolution reaction, hydrogen evolution reaction, and so on. Since such reactions are crucial for many engineering and scientific applications, in situ characterization techniques are required, which could capture such reactions happening at a different length and time scale. This article analyzes the recent progress made in the field of electrocatalyst's characterization using in situ neutron techniques. The article also paves the future path and has delineated the future challenges involved in multiscale correlative techniques (e.g., neutron techniques in the combination of synchrotron or microscopic techniques) used for getting the multiscale (atomic to micrometer range) mechanistic information about the electrocatalyst's working and degradation. 相似文献
60.
Gupta Sanjay Kumar Misra Rahul Dev 《Journal of Thermal Analysis and Calorimetry》2019,136(4):1781-1793
Journal of Thermal Analysis and Calorimetry - In order to decrease the energy consumptions in energy conversion devices, boiling heat transfer augmentation is one of the important research... 相似文献