查看更多>>摘要：An approach for experimental assessment of the trend of variations of the electron density at the basic center for series of substituted pyridines, based on the shifts of infrared O-H stretching frequencies of selected proton donating species upon hydrogen bonding with the pyridine derivatives [delta v(OH)(exp)], is validated. Strong correspondence between theoretically evaluated atomic charges (Hirshfeld, CM5) and the electrostatic potential for the pyridine nitrogen in the monomeric derivatives and spectroscopic data for the delta v(OH)(exp) shifts (ref. 7) is established. The spectroscopic shifts correlate also excellently with the rate constants for quaternization of substituted pyridines with ethyl iodide. The omega B97X-D/6-311++G(3df,2pd) method is used in the computations, conducted in the present research.
查看更多>>摘要：In this study, a Zn0.5Cd0.5S/BiOBr composite photocatalyst was constructed using an in situ growth technique. SEM and TEM revealed that the ZCS/BiOBr photocatalyst has an irregular sheet structure, and Zn0.5Cd0.5S particles form a heterojunction structure with BiOBr. The 70-Zn0.5Cd0.5S/BiOBr heterojunction exhibited the highest photocatalytic degradation efficiency for methylene blue, and the decolorization rate of MB was 99.52% in 240 min. The degradation rates were 1.83 and 4.76 times those of Zn0.5Cd0.5S and BiOBr, respectively. After four cycles, there was no significant decrease in photocatalytic activity; the main active substances involved in the degradation process were h(+ )and .OH.
Allafchian, AlirezaBalali, FaridehVahabi, Mohammad RezaJalali, Seyed Amir Hossein...
8页
查看更多>>摘要：This study describes a facile synthesis of spherical silver nanoparticles (AgNPs) mediated by the extract of Eryngium billardieri Delar. with antibacterial and cytotoxicity studies using normal L-929 cell line. It is found that nanometer sized (31.72 nm), uniform and well dispersed AgNPs are obtained as shown by XRD, UV-Vis, FT-IR, DLS and TEM measurements. It is evidenced that the tested Gram-negative strains are readily controlled, such that MIC values of 50 and 200 mu g/L are sufficient to inhibit them. The MTT cytotoxicity results indicate that the effect of nanoparticle on L-929 cell line is time and dose dependent.
查看更多>>摘要：A highly efficient and novel atomistic simulation framework is first established for the thermal and mechanical behaviors of a whole microprocessor chip or its constituent functional modules, important for the performance and reliability of high-end microprocessor circuits. The largest simulated module contains about 55.3 thousand nano-transistors with around 107 billion atoms. Traditionally, the macroscopic continuous methods are difficult to treat nanoscale factors such as doping, thin dielectric layer, surface and interface in the nano-transistor devices, while the microscopic quantum mechanics method can only calculate one or several nano-transistors. This proposed simulation method realizes the integrated treatment of the above nanoscale factors and complex gate layout by coupling multiple interatomic potential models for different materials and designing efficient parallel algorithms, and bridges the mesoscale simulation gap between the aforementioned macroscopic and microscopic methods. The development provides the first atomic-scale simulation framework for predicting and modulating the thermal behavior of a microprocessor circuit or its functional module, which paves an exciting way to the atomic-resolution design of novel high-performance microprocessor chips in the post-Moore era.
查看更多>>摘要：Ag@ZnO yolk-shell nanospheres (Ag@ZnO YSNSs) are fabricated via a simple sonochemical method for chemical sensor application. It is found that the Ag@ZnO YSNSs exhibits remarkable sensitivity and ultra-high response towards ethanol vapor. Compared with the pristine ZnO hollow nanosphere (ZnO HNSs), Ag@ZnO YSNSs based gas sensor reduced the optimum working temperature from 420 to 320 ?, shorten the response/recovery time from 55/18 to 23/15 s, optimized the detection limit from 5.20 to 0.88 ppm, and enhanced the sensor response from 66 to 250. The unique yolk-void-shell nanostructure, the catalytic effect of noble metal Ag and abundant oxygen vacancies in Ag@ZnO YSNSs are responsible for that improvement.
查看更多>>摘要：We present a method to generate the high-order single harmonics on the harmonic spectra. It is shown that by properly choosing the chirp parameters, the laser intensities and the pulse durations of two-color chirped pulse, the high-order single and even double harmonics can be enhanced and generated on the harmonic spectra. The reason behind the single and double harmonic generation is because the nonlinear electron acceleration in the chirp region caused by the reversed sub-peak structure. The results are beneficial to the generation of single and double harmonic light sources.
查看更多>>摘要：The analysis of spin-lattice relaxation in nuclear quadrupole resonance (NQR) of spin -5/2 reported by Okubo and Igarashi (Z. Naturforsch. A. 56 (2001) 777) is extended to take account of the distribution of the initial non equilibrium populations created by a resonant radio-frequency pulse in powder. The proposed theory is applicable to axially symmetric electric field gradient tensor and is examined for spin-lattice relaxation of (127I) NQR in polycrystalline pyridine iodine monochloride measured at 469 MHz at 77 K.
查看更多>>摘要：NaBa12B7O21F4:xEu(3+) phosphors, where 0 < x <= 0.16, were obtained through the high temperature solid phase reaction method. The phosphors showed significant red fluorescence emission resulting from the dominant D-5(0)-> F-7(2) transitions. The optimum doping concentration of Eu3+ ions in the NaBa(12)B(7)O(21)F(4 & nbsp;)matrix were estimated to be 14 mol%. The phenomenon of concentration quenching was researched, and the concentration quenching of NaBa12B7O21F4:xEu(3+) phosphors maybe caused by the exchanging interaction of Eu3+ ions. Moreover, it was found that the optimal-component NaBa12B7O21F4:xEu(3+) phosphor showed high absolute luminescence quantum efficiency and had a millisecond fluorescence lifetime.
查看更多>>摘要：The cr-hole triel-bonded and cation-pi interactions are constructed in binary C5H5Tr center dot center dot center dot N-base and ternary Li+center dot center dot center dot C5H5Tr center dot center dot center dot N-base complexes (Tr--B, Al, Ga and N-base--NCH, NH3, NC-). A positive region of electrostatic potential appears near the triel (Tr--B, Al, Ga) atom in the plane of the aromatic ring after replacing the CH group of benzene by a triel atom. Using MP2/aug-cc-pVTZ method, the solvation effect and cooperativity effect were investigated by MEP, ELF, AIM and SAPT analysis. The results indicate that the cooperative effects between cr-hole triel-bonded and cation-pi interactions in Li+center dot center dot center dot C5H5Tr center dot center dot center dot N-base complexes are positive and will be weakened in water environment.
查看更多>>摘要：The polyvinylpyrrolidone (PVP-K30) stabilized iron-nickel bimetallic nanocomposites (PVP-nZVI/Ni) were successfully synthesized by the liquid-phase reduction, and they were designed for the adsorption/reduction of Cr(VI). The kinetics and isotherm experiments at different pH, initial concentrations and temperatures were conducted to analyse the removal mechanism. These results were further explained by the characterization before and after the reaction. Batch experiments showed that PVP-nZVI/Ni could maintain high removal amount of Cr(VI) at a wide pH region of 2 to 7 and equilibrium could be reached within 10 min at a maximum removal amount of 400 mg/g, indicating its potential of removing Cr(VI) from wastewater.
NSTL
Elsevier