Journal of Analytical Chemistry - In this article, a new spectrofluorometric method was developed for the determination of methamphetamine based on a turn-on luminescence response of captopril... 相似文献
The problem of controlling the relative position and velocity in multi-spacecraft formation flying in the planetary orbits is an enabling technology for current and future research. This paper proposes a family of tracking controllers for different dynamics of Spacecraft Formation Flying (SFF) in the framework of port-Hamiltonian (pH) systems through application of timed Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC). The leader–multi-follower architecture is used to address this problem. In this regard, first we model the spacecraft motion in the pH framework in the Earth Centered Inertial frame and then transform it to the Hill frame which is a special local coordinate system. By this technique, we may present a unified structure which encompasses linear/nonlinear dynamics, with/without perturbation. Then, using the timed IDA-PBC method and the contraction analysis, a new method for controlling a family of SFF dynamics is developed. The numerical simulations show the efficiency of the approach in two different cases of missions.
The electrochemical properties of vanadyl(IV) derivatives, namely salen Schiff base complexes of the type [VO(Salen)] (5-BrSalen, 5-NO2Salen, 5-MeOSalen, salpn (bis(salicylaldehyde)-1,3-propanediamine, 5-BrSalpn, 5-NO2Salpn, 5-MeOSalpn, Me2Salen, Salophen, 5-BrSalophen, and 5-MeOSalophen) were investigated. The equatorial Schiff base ligands affect the oxidation potentials via interaction with the d-orbitals of the vanadyl metal ion. The cathodic peak potential (Epc) becomes less negative according to the sequence MeO- < H- < Br- < NO2?. 相似文献
A theoretical investigation of the effect of different parameters on the flow and the temperature fields in a radiofrequency
inductively coupled plasma is carried out. The parameters studied are: central injection gas flow rate, total gas flow rate,
input power, and the type of plasma gas. The results obtained for argon and nitrogen plasmas at atmospheric pressure indicate
that the flow and the temperature fields in the coil region, as well as the heat flux to the wall of the plasma confinement
tube, are considerably altered by the changes in the torch operating conditions. 相似文献
A sensitive stripping voltammetric procedure for quantifying thorium is described. The chelate of thorium with the azo dye Mordant Blue 9 is adsorbed on the hanging mercury drop electrode, and the reduction current of the accumulated chelate is measured during a negative-going potential scan. Cyclic voltammetry is used to characterize the interfacial and redox behaviors. The effects of pH, dye concentration and accumulation potential are discussed. The detection limit is 4 × 10?10 M (4-min accumulation), a linear current-concentration relationship is observed up to 1.3 × 10?7 M, and the relative standard deviation (at the 6 × 10?8 M level) is 3.1%. Possible interferences by trace metals and organic surfactants are investigated. Simultaneous quantitation of thorium and nickel is illustrated. 相似文献
The chemiluminescence arising from the reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of acriflavine has been studied. The relationship between the chemiluminescence intensity and concentrations of TCPO, H2O2, acriflavine and the base sodium salicylate are reported. The kinetic parameters for the peroxyoxalate-chemiluminescence (PO-CL) of acriflavine were evaluated from the computer fitting of the corresponding chemiluminescence intensity-time plots. 相似文献
Following recent experimental works, herein we investigated chemical functionalization of a BN graphene-like sheet with hydrazine (N2H4) molecule based on the density functional theory. We found that the functionalization of the pristine sheet is not possible; while the presence of some structural defects such as Stone–Wales is essential to make it feasible. Functionalization energy of the defected sheet is calculated to be in the range of ?6.1 to ?7.4 kcal/mol at B3LYP/6-31G (d) level. Based on the obtained results, the functionalized BN sheet is found to be more soluble in water in comparison with the pristine sheet which is in good agreement with previous experimental reports. Also, it was found that the electronic properties of the defected sheet are slightly changed upon the chemical functionalization. 相似文献
We present novel inorganic–organic hybrid catalyst to accomplish domino multi‐component reaction (MCR) for synthesis of 3‐amino‐2′‐oxospiro[benzo[c]pyrano[3,2‐a]phenazine‐1,3′‐indoline]‐2‐carbonitrile/carboxylate derivatives. This methodology offers remarkable development by easy production of H3PMo12O40/Hyd‐SBA‐15 in regard to solving the problem of using harsh catalysts, also it demonstrates to be impressive and environmentally friendly in term of low reaction times and high yields. 相似文献