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101.
The application of contact transformation theory to the perturbed harmonic oscillator is reexamined in the light of the harmonic oscillator tensors previously presented. It is found that the recasting of the formalism of this problem in terms of harmonic oscillator tensors results in great simplifications, most of which stem from the introduction of the additional algebraic quantum numbers (l, m). The order of magnitude of each fragment of the Hamiltonian is easily recognizable, and the diagonal and nondiagonal parts contained therein are readily identifiable. The determination of the contact transformation operator is reduced to a simple formula. First, an analysis is made for a single mode of vibration, and it is subsequently extended to a multimode case. The perturbed diatomic vibrator is presented as an example. 相似文献
102.
Summary Copper(II) complexes derived from substituted cinnamic acids 3, 4-dimethoxycinnamic acid (3, 4-DMCH) and 3, 5-dimethoxycinnamic acid (3, 5-DMCH), of the formula [Cu(3, 4-DMC)2]·H2O (1), [Cu(3, 5-DMC)2]·H2O (2) were prepared. The magnetic properties of the complexes suggest dimeric structures typical of copper(II) acetate monohydrate-like complexes. X-band e.s.r. spectra of polycrystalline samples at low temperature are typical of triplet state systems S=1. Their ability to catalyze the aerial oxidation of 3, 5-di-t-butylcatechol was measured spectrophotometrically at 30°C. The complexes are models for oxidases. 相似文献
103.
A function is presented to test equality between lists. In any case the function requires at most one single traversal of the lists and behaves as follows:
- if there are no cycles, it works as standardEQU AL functions;
- if there are cycles, it does not give information about equality, but it can detect cycles, i.e. it signals which lists are cyclic.
104.
105.
Friedrich Boberg Maria Ruhr Karl-Heinz Garburg Alfons Garming 《Journal of heterocyclic chemistry》1986,23(3):759-766
Dihydro-1,2-oxazines 8 and 12-oxazines 12 are formed by the reaction of the nitronic acids of the adducts of α-nitroolefins and β-dicarbonyl compounds ( 6 ) by two ways: A ) The nitronic acids 6 are heated in a boiling solution of urea in ethanol or methanol. B ) The nitronic acids 6 are reduced with an aqueous solution of ammoniachloride and sodium sulfide. 1H-nmr and 13C-nmr investigations prove the constitutions. The mechanism is discussed. 相似文献
106.
Michèle Decouzon Jean-Fraçois Gal Jérôme Gayraud Pierre-Charles Maria Gian-Angelo Vaglio Paolo Volpe 《Journal of the American Society for Mass Spectrometry》1993,4(1):54-57
An accurate gas-phase acidity for germane (enthalpy scale, equivalent to the proton affinity of GeH3 ?), ΔH acid o(GeH4) = 1502.0 ± 5.1 kJ mol?1, is obtained by constructing a consistent acidity ladder between GeH4, and H2S by using Fourier transform-ion cyclotron resonance spectrometry, and 0 and 298.15 K values for the first bond dissociation energy of GeH4 are proposed: D0 o(H3Ge-H) = 352 ± 9 kJ mol?1; D o(H3Ge-H) = 358 ± 9 kJ mol?1, respectively. These results are compared with experimental and theoretical data reported in the literature. Methylgermane was found to be a weaker acid than germane by approximately 35 kJ mol?1: ΔH acid o = 1536.6 kJ mol?1. 相似文献
107.
Maurício Cavicchioli Antonio Carlos Massabni Luciana Rebelo Guilherme Eduardo Ernesto Castellano Armando Paduan-Filho Ana Maria da Costa Ferreira 《Transition Metal Chemistry》2007,32(3):355-361
Structural, electrochemical and spectroscopic data of a new dinuclear copper(II) complex with (±)-2-(p-methoxyphenoxy)propionic acid are reported. The complex {tetra-μ-[(±)-2-(p-methoxyphenoxy)propionato-O,O′]-bis(aqua)dicopper(II)} crystallizes in the monoclinic system, space group P21/n with a = 14.149(1) ?, b = 7.495(1) ?, c = 19.827(1) ?, β = 90.62(1) and Z = 4. X-ray diffraction data show that the two copper(II) ions are held together through four carboxylate bridges, coordinated
as equatorial ligands in square pyramidal geometry. The coordination sphere around each copper ion is completed by two water
molecules as axial ligands. Thermogravimetric data are consistent with such results. The ligand has an “L” type shape due
to the angle formed by the β-carbon of the propionic chain and the linked p-methoxyphenoxy group. This conformation contributes to the occurrence of a peculiar structure of the complex. The complex
retains its dinuclear nature when dissolved in acetonitrile, but it decomposes into the corresponding mononuclear species
if dissolved in ethanol, according to the EPR measurements. Further, cyclic voltammograms of the complex in acetonitrile show
that the dinuclear species maintains the same structure, in agreement with the EPR data in this solvent. The voltammogram
shows two irreversible reduction waves at E
pc = −0.73 and −1.04 V vs. Ag/AgCl assigned to the Cu(II)/Cu(I) and Cu(I)/Cu° redox couples, respectively, and two successive oxidation waves at E
pa =− 0.01 and +1.41 V vs. Ag/AgCl, assigned to the Cu°/Cu(I) and Cu(I)/Cu(II) redox couples, respectively, in addition to the oxidation waves of the
carboxylate ligand. 相似文献
108.
This paper presents a simple, rapid and reproducible method of analysis of salbutamol in pharmaceutical products, utilizing batch injection analysis (BIA) associated with amperometric detection. A study of salbutamol oxidation demonstrated a strong dependence between electrode fouling and pH. All determinations were done utilizing a glassy carbon electrode in presence of 3.0 mol l−1 NaOH. A large linear dynamic range from 8×10−7 to 2×10−4 mol l−1 was obtained by using an injected volume of 100 μl with a detection limit of 2.5×10−7 mol l−1. R.S.D. of 0.92% for 50 successive injections of 4×10−6 mol l−1 of salbutamol and a sample throughput of 60 samples per hour were achieved. The method was applied for salbutamol quantification in syrups. 相似文献
109.
Maria Cristina Righetti Maria Laura Di Lorenzo Elpidio Tombari 《European Polymer Journal》2007,43(11):4726-4738
The isothermal crystallization kinetics and melting behavior of poly(butylene terephthalate) (PBT) in binary blends with poly(ε-caprolactone) (PCL) was investigated as a function of PCL molecular mass by differential scanning calorimetry and optical microscopy. The components are miscible in the melt when oligomeric PCL (Mw = 1250) is blended with PBT, whereas only partial miscibility was found in mixtures with higher molecular mass (Mw = 10,000 and 50,000). The equilibrium melting point of PBT in the homopolymer and in blends with PCL was determined through a non-linear extrapolation of the Tm = f(Tc) curve. The PBT spherulitic growth rate and bulk crystallization rate were found to increase with respect to plain PBT in blends with PCL1250 and PCL10000, whereas addition of PCL50000 causes a reduction of PBT solidification rate. The crystallization induction times were determined by differential scanning calorimetry for all the mixtures through a blank subtraction procedure that allows precise estimation of the crystallization kinetics of fast crystallizing polymers. The results have been discussed on the basis of the Hoffman-Lauritzen crystallization theory and considerations on both the transport of chains towards the crystalline growth front and the energy barrier for the formation of critical nuclei in miscible and partially miscible PBT/PCL mixtures are widely debated. 相似文献
110.
Erik G.P. da Silva Ana Carolina do N. Santos Antnio C.S. Costa Dalva M. da N. Fortunato Ndia M. Jos Maria G.A. Korn Walter N.L. dos Santos Srgio L.C. Ferreira 《Microchemical Journal》2006,82(2):159-162
In the present work, a slurry sampling flame atomic absorption spectrometric method to determine directly manganese and zinc in powdered chocolate samples is proposed. The optimization step was performed using univariate methodology involving the following factors: nature and concentration of the acid solution, sonication time, and particle size. The established conditions led to the use of a sample mass of 150 mg, 2.0 mol L− 1 nitric acid solution, sonication time of 15 min, and a slurry volume of 50 mL. This method allows the determination of manganese and zinc with detection limit of 52 and 61 ng g− 1, respectively, and a precision expressed as relative standard deviation (RSD) of 2.6% and 3.2% (both, n = 10) for contents of manganese and zinc of 52.4 and 100.0 μg g− 1, respectively. The proposed method was applied for determination of manganese and zinc in five powdered chocolate samples. In these, the manganese content varied from 42.8 to 52.7 and from 88.6 to 102.4 μg g− 1 of zinc. The analytical results were compared with the results obtained by analysis of these samples after digestion using open vessel and acid bomb digestion procedures and determination using FS-FAAS. The statistical comparison by t-test (95% confidence level) showed no significant difference between these results. 相似文献