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51.
Formation and stability of room-temperature deposited amorphous (a-) alloy films of Ge with Ag, Au, Cu, Ni, Fe, Ga, In, Sn, Sb, Ni, Bi and Nb have been studied, using differential thermal analysis and electron microscopy, as a function of various parameters such as: solubility of alloying element (in c-Ge), its melting point, atomic size and electonegativity. It has been shown that the composition range R, up to which amorphous alloy films are obtained, is affected by the solubility of the alloying element and its melting point. The effect of solubility S is dominant when S > 1 at%. However, for , the range is entirely governed by the melting point of the alloying element. Solubility and melting point have also been found to play a decisive role in stabilizing the amorphous phase of Ge. However, atomic size and electronegativity differences do not seem to play any important role in either the formation or stability of the amorphous phase. 相似文献
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53.
Devandar Chauhan Prashant Kumar Nagar Kamakshi Pandey Harsh Pandey 《Macromolecular Symposia》2024,413(1):2300053
The world is constantly challenged regarding managing environmental and ecological contamination due to human and industrial activities. This is because of the constant threat posed by pollution. Nowadays, membrane-based technology is a growing field, making practically all the separation of foulant from wastewater possible. The membrane fouling resulting from the interaction between the foulant and the membrane surface presents a challenge for the technology in maintaining performance over extended periods of operation. As a result, there is a rising interest in research focusing mainly on creating patterned membrane surfaces that reduce fouling and effectively enhance the surface area. This article comprehensively overviews the most recent and cutting-edge techniques that can be applied to modify and construct high-performance patterned membranes suitable for ultrafiltration, microfiltration, nanofiltration, and reverse osmosis (UF, MF, NF, and RO) water purification processes. In this study, recent developments in membrane material are dissected, focusing on methods for improving surface chemistry, structure, and hydrodynamics, as well as the consequences of these characteristics on filtering performance. 相似文献
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R. C. Chopra 《Zeitschrift für Physik A Hadrons and Nuclei》1973,260(4):315-324
TheE2 andM1 reduced transition probabilities between the low lying levels, in the case of79Br and81Br, have been calculated on the core-excitation model. To account for the observed M1 transition probabilities admixture among the like spin states is considered. In addition, the ground state static moments have been computed. For the same amount of admixture among the like spin states, a good agreement with the experimental results is obtained, for both79Br and81Br. The results are compared with other existing theoretical calculations. From our analysis, we obtain, the quadrupole moment of the first excited 2+ state in the neighbouring even-even nuclei. It is in good agreement with the value calculated on the basis of the anharmonic vibrational model. 相似文献
56.
The photoinduced shift in the optical absorption edge and changes in the optical constants and their dispersion in the vicinity of the absorption edge (2–5 eV) have been studied in obliquely deposited thin films of Ge-chalcogenides. The variation of photo-optical changes as a function of various deposition conditions and composition throws light on the role of built-in microstructure and the relevant physical parameters necessary for the occurrence of large photoeffects. The photoinduced optical changes in 80°-films are partly (≈33%) reversible. This (reversible) part is equal to the total (completely reversible) optical changes in 0°-films. The irreversible part (≈67%) has been attributed to the observed photoinduced volume changes. The reversible optical changes have been understood in terms of configurational distortion and modifications in the electronic energy band structure, near the band edges induced by band gap irradiation. 相似文献
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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
59.
B. Josephson G. Jungner J. G. Reinhold D. W. Wilson L. Cuny Y. Abe S. Kawaguchi A. v. Christiani V. Anger O. Rosenheim R. Ehrström K. Täufel H. Thaler G. Widmann E. Kirk W. R. Bloor H. H. Williams B. N. Erickson I. Avrin S. S. Bernstein I. G. Macy G. Ellis L. A. Maynard R. N. Chopra A. C. Roy R. Feulgen H. Grünberg K. Imhäuser C. A. Grau V. Oliva E. Epstein H. Lieb 《Analytical and bioanalytical chemistry》1941,122(3-4):149-160
60.
Simperler A Kornherr A Chopra R Jones W Motherwell WD Zifferer G 《Physical chemistry chemical physics : PCCP》2007,9(30):3999-4006
The lactonisation of a CCR1 inhibitor (CC chemokine receptor 1, involved in autoimmune diseases) featuring a hydroxyl group in a gamma-position (gamma-OH) with respect to an amide group has been investigated in silico. The two key steps of the lactonisation reaction are (i) rearrangement to an optimal conformation and (ii) the formation of the lactone (ring closure) and expulsion of NH3. Quantum chemical calculations in the gas phase were employed to identify conformers of the molecule with favorable starting geometries for a lactonisation reaction. In total, calculations of 1296 conformers revealed that it is energetically feasible for an inhibitor molecule to adopt a conformation where the carbon atom of the amide group (C(amide)) is suitably close to the oxygen atom of the gamma-OH (O(gamma)) to facilitate a successful lactonisation reaction. Additionally, molecular dynamics methods were used to show that rearrangement to a suitable conformer for lactonisation to occur happens to a lesser extent when the CCR1 inhibitor was embedded in an amorphous trehalose matrix (a model carbohydrate excipient). The mechanism of the actual lactonisation was investigated using the complete Linear Synchronous Transit/Quadratic Synchronous Transit (LST/QST) method. This was performed in both the gas phase and in water and was found to be a concerted reaction. 相似文献