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1.
The resistivity of composite nonlinear resistors (varistors) consisting of zinc oxide ceramic and high-density polyethylene, as well as IR spectra and X-ray diffraction patterns taken of the samples, are studied. The component composition of the resistor is shown to influence its resistivity and IR and X-ray spectra.  相似文献   
2.
The one-pot reaction between the novel proton transfer compound (pydaH2)2+(phendc)2−, LH2, and Cu(II) afforded the compounds (pydaH)2[Cu(phendc)2]·10H2O, 1, and (pydaH)2[Cu(phendc)(phendcH)]2·5H2O, 2, where pyda=2,6-diaminopyridine, and phendcH2=1,10-phenanthroline-2,9-dicarboxylic acid. The single crystal X-ray diffraction analysis of 1 and 2 revealed that these are two novel self-assembled 3D Cu(II) complex-organo-networks, in which (pydaH)+ ions and [Cu(phendc)2]2− or complex units are held together by ion pairing, H-bonding, and π–π interactions. Magnetic measurements over the temperature range 1.8–310 K revealed no significant magnetic coupling between Cu(II) centers in 1 or 2.  相似文献   
3.

A study on expansion flow inside a nozzle considering full mechanism chemistry of hydrogen and oxygen was carried out. In this study, a full implicit scheme for turbulent reactive flow was obtained by combining the second order TVD scheme of Yee and Harten (1987, Implicit TVD schemes for hyperbolic conservation laws in curvilinear coordinates. American Institute of Aeronautics and Astronautics Journal, 25(2), 266–274) with the efficient implicit lower-upper scheme of Shuen and Yoon (1989, Numerical study of chemically reacting flows using a lower-upper symmetric successive overrelaxation scheme. American Institute of Aeronautics and Astronautics Journal, 27(12), 1752–1756). The species equations, Navier–Stokes equations and turbulence model were implemented in the numerical scheme and solved in conjunction with full detailed finite rate chemistry. The numerical scheme is verified by comparison with experimental results of a converging–diverging nozzle. Effects of inlet pressure, temperature and fuel-oxidant mass ratio on nozzle flow field were studied. Variation of chemical species under different conditions was investigated by considering a chemical mechanism. Results show that increasing inlet pressure increases the rate of reactions due to increasing the concentration of reactants. For lower inlet pressure the radical H increases slightly in the diverging part of the nozzle, while for higher pressures it decreases along the nozzle. Inlet fuel–oxidant mass ratio affects the variation of all species with a greater effect for a near stoichiometric ratio. It was also shown that a higher inlet temperature provides a more enhanced reaction zone in the diverging part of the nozzle.  相似文献   
4.
Abstract

Synthesis of polyfunctionalized ketenimines via three-component reactions of rhodanine and 5-(4-dimethylaminobenzylidene)-rhodanine with dialkyl acetylenedicarboxylates and alkyl isocyanides is described. The reactions proceed smoothly under mild conditions leading to the desired products in good yields. In the case of methyl acetylenecarboxylate, the reaction led to methyl (Z)-3-({5-[(E)-1-(tert-butylamino)methylidene]-4-oxo-4,5-dihydro-1,3-thiazol-2-yl}sulfanyl)-2-propenoate in low yield.

GRAPHICAL ABSTRACT   相似文献   
5.
We study superdense coding with uniformly accelerated particle in single mode approximation and beyond single mode approximation. We use four different functions, the capacity of superdense coding, negativity, discord and the probability of success for evaluating the final results. In single mode approximation, all the four functions behave as expected, however in beyond single mode approximation, except the probability of success, the other three functions represent peculiar behaviors at least for special ranges where the beyond single mode approximation is strong.  相似文献   
6.
Inverse bremsstrahlung (collisional) absorption of the laser beam is studied in plasma with a generalized (q-nonextensive) electron velocity distribution and some kind of generalized electron density profile. It is shown that for some values of parameters designating the q-nonextensive electron velocity distribution function and its generalized density profile, the calculated absorption coefficient reduces to the already known cases with Maxwellian velocity distribution with linear and exponential density profiles.  相似文献   
7.
<正>In this work,we describe a new strategy for the electrochemical determination of captopril(CA) using ferrocenemonocarboxylic acid as a mediator and multiwall carbon nanotubes as sensors in aqueous solution at pH 7.0.The diffusion coefficient(D),and the kinetic parameters such as electron transfer coefficient(α).and heterogeneous rate constant(k_h),for CA were also determined using electrochemical approaches.Under the optimized conditions,the electrocatalytic oxidation peak current of captopril showed two linear dynamic ranges with a detection limit of 0.3×10~(-6) mol L~(-1) captopril.The linear calibration range was 0.8×10~(-6) to 65×10~(-6) mol L~(-1) using cyclic voltammetry.Finally,this modified electrode was also examined as a selective,simple and precise new electrochemical sensor for the determination of captopril in real samples such as drug and patient human urine.  相似文献   
8.
The Ni(II) complexes [Ni(L)2](ClO4)2 (1) and [Ni(L)2(NO3)2] (2), where L is the Schiff base ligand of 4,5,9,13,14-pentaaza-benzo[b] triphenylene, were synthesized and characterized by physico-chemical and spectroscopic methods. Nano-sized particles of (1) were prepared both by sonochemistry (3) and solvothermal (4) methods. NiO nanoparticles were obtained by calcination of the nano-structure complexes at 500 °C. The structures of the nano-sized compounds were characterized by X-ray powder diffraction and scanning electron microscopy. The thermal stabilities of the bulk complexes (1–2) and nano-sized particles (3–4) were studied by thermogravimetric and differential scanning calorimetry. The catalytic activities of complexes of (1–4) are reported. The free Schiff base and its Ni(II) complexes have been screened for antibacterial activities against three Gram-positive bacteria. The metal complexes are more active than the free Schiff base. Electrochemical studies show that the Ni complexes undergo irreversible reduction in MeCN solution.  相似文献   
9.
<正>The addition of 2,4-dihydroxyaceto(and benzo)phenone to propiolic ester is catalyzed by triphenylphosphine or tert-butyl isocyanide to form O-vinyl aryl derivatives in fairly good yields.  相似文献   
10.
In this paper, we investigate the positivity property for a class of 2-stage explicit Runge-Kutta (RK2) methods of order two when applied to the numerical solution of special nonlinear initial value problems (IVPs) for ordinary differential equations (ODEs). We also pay particular attention to monotonicity property. We obtain new results for positivity which are important in practical applications. We provide some numerical examples to illustrate our results.  相似文献   
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