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21.
We carried out an efficient and facile synthesis of Zn(II) complexes with heterocyclic ligands based on 2-substituted benzothiazole moieties, 2-(2′-hydroxynaphthyl)benzothiazole, 2-(2′-hydroxyphenyl)benzothiazole, and 2-(2′-merceptophenyl)benzothiazole, and amino acids, glycine and alanine, are reported and also examined for antifungal and antibacterial activities. Ligands and complexes were characterized by FTIR, 1H NMR, and elemental analysis. 相似文献
22.
We propose a new method for image encryption using fractional Fourier transform and chaos theory. Random phase masks are generated using iterative chaos functions. The input image is combined with the first random phase mask at the object plane and is then transformed using the fractional Fourier transform. After the first fractional Fourier transform, the second random phase mask, again generated by using the chaos functions, is used at the fractional plane. The second fractional Fourier transform operation is then carried out to obtain the encrypted image. Three types of chaos functions have been used: the logistic map, the tent map and the Kaplan–Yorke map. The mean square error and the signal-to-noise ratio between the decrypted image and the input image for the correct order and the incorrect order of the fractional Fourier transform have been calculated. The computer simulations are presented to verify the validity of the proposed technique. 相似文献
23.
Mathematical Notes - Michael Somos discovered several theta-function identities of various levels by computer and offered no proof for them. These identities highly resemble some of... 相似文献
24.
In the last few decades, there has been enormous growth in ferrite nanoparticles. Magnetic, optical, and electrical properties of ferrites gain consideration due to their use in various applications such as rechargeable lithium batteries, medical diagnostics, solar energy devices, and so forth. A vast increase in interest in ferrite nanoparticles has led them to be used as catalysts in various applications as they possess a large surface area-to-volume ratio. Furthermore, iron-based magnetic characteristics make it simple to retrieve catalysts by using an external magnet. Iron's catalytic potential, however, is far less than copper's. Therefore, the catalytic scope is substantially increased by substituting copper within the crystal lattice. Recently copper ferrite nanoparticles have caught the interest of numerous researchers due to low-cost magnetic material, stability under diverse conditions, and ease at which catalyst can be retrieved using an external magnetic field and utilized repeatedly. This review of data from year 2010 through 2022 emphasizes the synthesis method, structure, application in dyes degradation, catalytic potential in the number of coupling reactions, recyclability, and reusability of the magnetic catalyst. 相似文献
25.
G. Siddaramana Gowd Manoj Kumar Patra Sandhya Songara Anuj Shukla Manoth Mathew Sampat Raj Vadera Narendra Kumar 《Journal of luminescence》2012,132(8):2023-2029
Eu3+ doped Y2O3 nanophosphors have been synthesized using the simple colloidal precipitation method. Doping of Eu3+ ions in host yttria lattice has been achieved through slow re-crystallization process under wet-chemical conditions followed by annealing at high temperatures (300–1400 °C). The nanophosphors were characterized by using powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and spectrofluorometer techniques. XRD analysis reveals formation of pure cubic phase of Y2O3 in samples annealed at 700 °C or above. Further, the XRD data was successfully used to retrieve the crystallite size and size distribution from powder samples using the FW((1/5)/(4/5))M method. Crystallite size (11–50 nm) extracted from XRD has been found to be consistent with AFM measurements. The PL emission spectra of nanophosphors show bright red emission at 612 nm due to hypersensitive electric dipole (ED) 5D0–7F2 transition of Eu3+ ions in Y2O3 lattice. Further, photoluminescence studies indicate that optimum value of the Eu3+ to get best luminescence properties is 12 at%. Surface conjugations of these nanophosphors with water soluble dextran biomolecules have also been performed. Surface conjugated rare earth nanophosphors have great potential for bio-applications. 相似文献
26.
Angshuman Ghosh Soumen Kumar Dubey Dr. Maxcimilan Patra Jishu Mandal Narendra Nath Ghosh Priyanka Das Arpita Bhowmick Dr. Keka Sarkar Dr. Suprabhat Mukherjee Rajat Saha Dr. Subham Bhattacharjee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(63):e202201621
We have shown solvent- and substrate-dependent chiral inversion of a few glycoconjugate supramolecules. (Z)-F-Gluco, in which d -glucosamine has been attached chemically to Cbz-protected l -phenylalanine at the C terminus, forms a self-healing hydrogel through intertwining of the nanofibers wherein the gelators undergo lamellar packing in the β-sheet secondary structures with a single chiral handedness. Dihybrid (Z)-F-gluco nanocomposite gel was prepared by in-situ formation of silver nanoparticles AgNPs in the gel; this enhances the mechanical properties of the composite gel through physical crosslinking without altering the packing pattern. In contrast, (Z)-L-gluco bearing an l -leucine moiety does not form a hydrogel but an organogel. Interestingly, the chiral handedness of the aggregates of (Z)-L-gluco can be reversed by choosing suitable solvents. In addition to self-healing behavior, (Z)-L-gluco gel revealed shape persistency. Further, (Z)-F-gluco hydrogel is benign, nontoxic, non-immunogenic, and non-allergenic in animal cells. AgNP-loaded (Z)-F-gluco hydrogel showed antibacterial activity against both Gram-positive and Gram-negative bacteria. 相似文献
27.
28.
Magnesia (MgO) ceramic was machined using a pulsed Nd:YAG laser. A mathematical model was developed to predict machined effects. The model took into account the physical phenomena taking place during machining of the ceramic such as multiple reflections influencing the absorbed laser energy, thermal effects in vaporizing the material, dissociation energy losses and effect of vapor pressure in producing a cavity through the ceramic. The laser fluence, machining time and number of pulses required for machining a certain depth of cavity and the efficiency of machining in terms of the specific machining depth were estimated and compared with the experimental data, thus making the model useful for advance energy predictions and enhancement of machining efficiency. 相似文献
29.
N. Narendra 《Tetrahedron letters》2010,51(47):6169-6173
A simple protocol for the synthesis of a new class of trithiocarbonate-linked peptidomimetics and neoglycosylated amino acids is described. N-Protected amino alkyl thiols were treated with CS2 in the presence of triethylamine (TEA) to generate trithiocarbonate salt, which upon reaction with appropriate halides afforded dipeptidomimetics in good yields. Further, the procedure was also extended for the synthesis of N,N′-orthogonally protected trithiocarbonate-linked dipeptidomimetics. 相似文献
30.
K. Narendra Ch. Srinivasu Sk. Fakruddin P. Narayanamurthy 《The Journal of chemical thermodynamics》2011,43(11):1604-1611
The density, ultrasonic velocity, and viscosity of binary mixtures of (anisaldehyde + o-cresol, or +m-cresol, or +p-cresol) have been measured over the entire range of composition at T = (303.15, 308.15, 313.15, and 318.15) K. Using these data, various thermo-acoustic parameters such as deviation in adiabatic compressibility, Δβ, excess molar volume, VE, viscosity deviation, Δη and excess Gibb’s free energy of activation for viscous flow, ΔG1E have been calculated. The calculated deviation and excess functions have been fitted to the Redlich–Kister polynomial equation. The negative and positive values of deviation or excess thermo-acoustic parameters observed have been explained on the basis of the intermolecular interactions present in these mixtures. 相似文献