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81.
82.
Priya Kush Sanjeev Kumar Ujjain Dr. Navin Chand Mehra Dr. Pika Jha Dr. Raj Kishore Sharma Dr. Sasanka Deka 《Chemphyschem》2013,14(12):2793-2799
A simple, yet novel hydrothermal method has been developed to synthesize surfactant‐free Cu2ZnSnS4 nanocrystal ink in water. The environmentally friendly, 2–4 nm ultrafine particles are stable in water for several weeks. Detailed X‐ray diffraction (XRD) and high‐resolution transmission electron microscopy revealed the formation of single‐crystalline‐kesterite‐phase Cu2ZnSnS4. Elemental mapping by scanning electron microscopy/energy dispersive spectrometry corroborated the presence of all four elements in a stoichiometric ratio with minor sulfur deficiency. Finally, Raman spectroscopy ruled out the possible presence of impurities of ZnS, Cu2SnS3, SnS, SnS2, Cu2?xS, or Sn2S3, which often interfere with the XRD and optical spectra of Cu2ZnSnS4. X‐ray photoelectron spectroscopic studies of the as‐synthesized samples confirmed that the oxidation states of the four elements match those of the bulk sample. Optical absorption analyses of thin film and solution samples showed high absorption efficiency (>104 cm?1) across the visible and near‐infrared spectral regions and a band gap Eg of 1.75 eV for the as‐synthesized sample. A non‐ohmic asymmetric rectifying response was observed in the I–V measurement at room temperature. The nonlinearity was more pronounced for this p‐type semiconductor when the resistance was measured against temperature in the range 180–400 K, which was detected in the hot‐point probe measurement. 相似文献
83.
6-Triazolylpyridone derivatives were synthesized by coupling 4-(4-methoxyphenyl)-6-(1H-1,2,4-triazol-1-yl)-1-(3-chlorophenyl)pyridin-2(1H)-one with substituted benzenediazonium chlorides in the form of two isomers, which were separated by column chromatography and characterized by 1H and 13C NMR. Following the green approach, solvents were avoided as much as possible. The reaction monitoring was carried out by gas chromatography as well as thin-layer chromatography. The scope and limitation of the method are discussed. The structures of all the compounds have been assigned unambiguously on the basis of elemental analysis, infrared, and NMR spectral data and have been evaluated for antimicrobial and antitubercular activities. 相似文献
84.
Synthesis and In Vitro Antimicrobial Screening of New Azetidin‐2‐ones of 5‐Ethyl Pyridine‐2‐ethanol 下载免费PDF全文
Navin B. Patel Hemant R. Patel Faiyazalam M. Shaikh Dhanji Rajani 《Journal of heterocyclic chemistry》2014,51(3):775-787
A new series of azetidinones is described in this paper; Schiff base ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o ) were synthesized from 4‐[2‐(5‐ethylpyridin‐2‐yl)ethoxy]benzaldehyde, which was used to synthesize azetidinones ( 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m , 5n , 5o ), ( 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n , 6o ), and ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j , 7k , 7l , 7m , 7n , 7o ). The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, 1H NMR, and 13C NMR spectral data. All the products were screened against different strains of bacteria and fungi. Most of the monosubstituted and disubstituted chloro groups are more effective to both bacterial and fungal species in comparison with the standard drugs. 相似文献
85.
We present a solution to the problem of decoupling of a homonuclear two-spin system having weak isotropic scalar coupling. We describe non-selective pulse sequences that create an effective field perpendicular to the coupling interaction over a broad range of chemical shifts, with a magnitude proportional to the chemical shifts. Effective decoupling is achieved when the difference in chemical shifts imprinted on the perpendicular field is sufficiently larger than the coupling between the spins. The proposed methods scale down the chemical shifts. The pulse sequences may be useful in various applications in nuclear magnetic resonance spectroscopy. 相似文献
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87.
It was pointed out by P. Dorey that the three-point couplings between the quantum particles in affine Toda field theories have a remarkable Lie-theoretic interpretation. It is also well known that such theories admit quantum affine algebras as quantum symmetry groups, and widely believed that the quantum particles correspond to the so-called fundamental representations of these algebras. This led to the conjecture that Dorey's rule should describe when a fundamental representation occurs with non-zero multiplicity in a tensor product of two other fundamental representations. The purpose of this paper is to prove this conjecture, both for quantum affine algebras and for Yangians. The result reveals a hitherto unsuspected role played by Coxeter elements (and their twisted analogues) in the representation theory of these algebras. 相似文献
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89.
Surface oxidation of thin foils of NiMn alloy has been studied by transmission electron microscopy and electron diffraction. The surface was oxidized during bombardment with 50 keV protons at a residual pressure of 5 × 10?6 Torr at room temperature. In the first stage of oxidation small islands of MnO were formed on the surface of NiMn alloy. The oxide islands are irregularly distributed on both surfaces of the foil and are coherent with the NiMn base. Subsequent heating of the bombarded specimens was accompanied by formation of tetragonal MnO1.88 in an orientation where (110) MnO1.88z.dfnc; (101) NiMn. Comparison has been made with “normal” oxidation caused by heating of the specimens in approximately the same atmosphere. 相似文献
90.