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排序方式: 共有334条查询结果,搜索用时 15 毫秒
31.
In this paper, we find new proofs of modular relations for the Göllnitz-Gordon functions established earlier by S.-S. Huang and S.-L. Chen. We use Schröter’s formulas and some simple theta-function identities of Ramanujan to establish the relations. We also find some new modular relations of the same nature. 相似文献
32.
Rupom Borah Eramoni Saikia Sankar Jyoti Bora Bolin Chetia 《Tetrahedron letters》2017,58(12):1211-1215
A green and facile novel procedure has been developed for the synthesis of Cu2O nanoparticles within a very short reaction time using banana pulp extract as a reducing agent. The synthesized nanoparticles are well characterized by SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope) and powder XRD (X-ray Diffraction) methods. An environmental benign and highly efficient protocol for the ipso-hydroxylation of aryl and hetero arylboronic acids using bio-fabricated Cu2O nanoparticles as a catalyst and aqueous H2O2 as an oxidant has also been developed. The main advantages of this protocol are the base free reaction condition, reusable and heterogeneous catalytic system, and short reaction time with excellent yields. 相似文献
33.
Reenamoni Saikia Chaliha K. Annapurna Anal Tarafder V.S. Tiwari P.K. Gupta Basudeb Karmakar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):243-250
Precursor glass of composition 25K2O–25Nb2O5–50SiO2 (mol%) doped with Er2O3 (0.5 wt% in excess) was isothermally crystallized at 800 °C for 0–100 h to obtain transparent KNbO3 nanostructured glass–ceramics. XRD, FESEM, TEM, FTIRRS, dielectric constant, refractive index, absorption and fluorescence measurements were carried out to analyze the morphology, dielectric, structure and optical properties of the glass–ceramics. The crystallite size of KNbO3 estimated from XRD and TEM is found to vary in the range 7–23 nm. A steep rise in the dielectric constant of glass–ceramics with heat-treatment time reveals the formation of ferroelectric nanocrystalline KNbO3 phase. The measured visible photoluminescence spectra have exhibited green emission transitions of 2H11/2, 4S3/2 → 4I15/2 upon excitation at 377 nm (4I15/2 → 4G11/2) absorption band of Er3+ ions. The near infrared (NIR) emission transition 4I13/2 → 4I15/2 is detected around 1550 nm on excitation at 980 nm (4I15/2 → 4I11/2) of absorption bands of Er3+ ions. It is observed that photoluminescent intensity at 526 nm (2H11/2 → 4I15/2), 550 nm (4S3/2 → 4I15/2) and 1550 nm (4I13/2 → 4I15/2) initially decrease and then gradually increase with increase in heat-treatment time. The measured lifetime (τf) of the 4I13/2 → 4I15/2 transition also possesses a similar trend. The measured absorption and fluorescence spectra reveal that the Er3+ ions gradually enter into the KNbO3 nanocrystals. 相似文献
34.
Tin oxide (SnO2) thin films have been grown on glass substrates using atmospheric pressure chemical vapour deposition (APCVD) method. During
the deposition, the substrate temperature was kept at 400°C–500°C. The structural properties, surface morphology and chemical
composition of the deposited film were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and Rutherford
back scattering (RBS) spectrum. XRD pattern showed that the preferred orientation was (110) having tetragonal structure. The
optical properties of the films were studied by measuring the transmittance, absorbance and reflectance spectra between λ = 254 nm to 1400 nm and the optical constants were calculated. Typical SnO2 film transmits ∼ 94% of visible light. The electrical properties of the films were studied using four-probe method and Hall-voltage
measurement experiment. The films showed room temperature conductivity in the range 1.08 × 102 to 1.69 × 102 Ω−1cm−1. 相似文献
35.
We apply the extended transformation method to a non-power-law potential to generate a set of exactly solvable quantum systems in spaces of any dimensions. We derive exact analytic solutions of the Schrödinger equations with an exactly solvable non-power-law potential. For the transformed potentials obtained as a result, we calculate the quantized bound-state energy spectra and the corresponding wave functions. 相似文献
36.
Dechlorination of Ru(PPh3)2(TaiMe)Cl2 (TaiMe = p-Me-C6H4-N=N-C3H2NN(1)-Me (1), 1-methyl-2-(p-tolylazo)imidazole) has been carried out in acetone solution by Ag+ and reacted with N,N’-chelators to synthesise [Ru(PPh3)2 (TaiMe)(N,N’)]2+. The complexes have been isolated as their perchlorate salts. The N,N’ chelators are 1-alkyl-2-(phenylazo)imidazoles (PaiX,
X = Me, Et, CH2Ph); 2-(arylazo)pyridines, (Raap,p-R-C6H4-N=N-C5H4N; R = H, Me, Cl); 2-(arylazo)pyrimidines (Raapm,p-R-C6H4-N=N-C3N2H2; R = H, Me, Cl); 2,2’-bipyridine (bpy) and 1,10-phenanthroline (o-phen). Unsymmetrical N,N’ chelators may give two isomers
and this is indeed observed. The1H NMR spectral data refer to the presence of two isomers in the mixture in different proportions. With consideration of coordination
pairs in the order of PPh3, PPh3; N,N (N refers to N(immidazole)) and N’,N (N’ refers to N(azo)), the complexes have been characterised astrans-cis-cis andtrans-trans-trans configuration; the former predominates in the mixture. Electrochemical studies exhibit high potential Ru(III)/Ru(II) couple
and quasireversible N=N reduction. Electronic spectra show high intensity (ε ∼ 104) MLCT transition in the visible region (520 ±10) nm along with a shoulder (ε ∼ 103) in the longer wavelength region. 相似文献
37.
In this article, the similarity relations are studied, together with invertibility conditions and eigenvalues of intuitionistic fuzzy matrices (IFMs). Besides, idempotent, regularity, permutation matrix and spectral radius of IFMs are considered here with some properties and results for IFMs investigated. 相似文献
38.
We obtain approximate solutions of Altarelli-Parisi equations beyond leading logarithmic approximation. Our results suggest
quantitative utility of higher order terms in the structure function analysis of deep inelastic scattering. 相似文献
39.
Let G be a finite group G, K a field of characteristic p ≥ 17 and let U be the group of units in KG. We show that if the derived length of U does not exceed 4, then G must be abelian. 相似文献
40.
Das MR Sarma RK Saikia R Kale VS Shelke MV Sengupta P 《Colloids and surfaces. B, Biointerfaces》2011,83(1):16-22
A solution-based approach to the synthesis of silver (Ag) nanoparticles by chemical reduction of AgNO(3) in a graphene oxide (GrO) suspension is demonstrated. X-ray diffraction and transmission electron microscopy indicate that the Ag nanoparticles, of size range 5-25nm, were decorated on the GrO sheets. The size and shape of the Ag nanoparticles are dependent on the concentration of the AgNO(3) solution. Antimicrobial activity of such hybrids materials is investigated against the Gram negative bacteria Escherichia coli and Pseudomonous aeruginosa. The bacterial growth kinetics was monitored in nutrient broth supplemented with the Ag nanoparticle-GrO suspension at different conditions. It was observed that P. aeruginosa is comparatively more sensitive to the Ag nanoparticle-GrO suspension. 相似文献