The complete symmetrization of quantum operators: new thoughts on an old problem

The complete symmetrization with respect to x, p _x,... of the operators associated with dynamical properties can sometimes lead to results different from those obtained by the conventional quantum formalism based on the rule op (A ²)=(op A)². For example, angular momentum operators M _z ² and M ² are modified by the additive constants ²/2 and 3 ²/2 respectively (M ²0 for electron in the ground state of H atom, rotator never at rest, but spectra unchanged); the average quadratic dispersion of energy is different from zero. These results can be interpreted by assuming that the system is never strictly isolated but communicates with the other systems of the universe by means of electromagnetic interactions. Quantum mechanics would give only average values over a sufficiently long time and would exhibit a quasi-ergodic character. Examples supporting this possibility are given, in particular that of arsines for which quantum forecasts correspond to average values over one year.Dedicated to Professor J. Koutecký on the occasion of his 65th birthday     

Emission characteristics of high-powered microwave induced plasma optical emission spectrometry by using nitrogen–oxygen mixture gas

A high-powered, microwave-induced nitrogen–oxygen plasma (N₂–O₂–MIP) generated by using an Okamoto cavity at atmospheric pressure was investigated when the observation height, the flow rate of carrier gas, and the oxygen content were varied as the experimental parameters. The emission characteristics of the plasma were evaluated with regard to the excitation temperature and the intensity ratio of atomic line to ionic line. The excitation temperature of the N₂–O₂–MIP was in the range of 5100–5700 K when the oxygen content was varied from 0 to 30% at the observation height of 7 mm and the carrier gas flow rate of 0.6 l/min. The intensity ratio of atomic line to ionic line was elevated with an increase in the oxygen content.     

Molecular and crystalline structure of the enol form of (dimorpholinophosphoryl)chloroacetaldehyde and (dimorpholinophosphoryl)-dibromomethane

The crystal and molecular structures of the products of the halogenation of the dimorpholide of ethoxyvinylphosphonic acid were determined by the method of x-ray structure analysis. It was established that (dimorpholinophosphoryl)chloroacetaldehyde only exists in the crystals as the Z-enol [(Z)-1-hydroxy-2-(dimorpholinophosphoryl)-2-chloroethene] with intra- and intermolecular H-bonds (=CH...O=P and OH...O=P). The (dimorpholinophosphoryl)dibromomethane forms centrosymmetric eight-membered cyclic dimers in the crystals due to intermolecular CH...O=P H-bonds. The structure of the morpholine and phosphoryl groups in both compounds was discussed.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2730–2737, December, 1992.     

Mechanical behaviour of biodegradable agricultural films under real field conditions

The mechanical behaviour of various types of biodegradable materials depends on their chemical composition and additives, the processing characteristics and the application conditions. The environmental conditions during storage and usage of these materials strongly influence their mechanical properties and behaviour. Ageing and degradation during the useful lifetime of biodegradable agricultural films causes losses in the mechanical performance of the material, as measured by monitoring the evolution of some of the critical mechanical properties. Such losses may be comparable to the corresponding losses of the conventional polyethylene agricultural films due to ageing, or they may be more drastic. In the present paper, the overall mechanical and ageing/degradation behaviour of experimental specially designed and manufactured low-tunnel and mulching biodegradable films, exposed to full-scale field conditions is analysed. Selected critical mechanical properties of these films manufactured with different grades of Mater-Bi material and additives, different thickness and processing schemes and exposed to real cultivation conditions in four different locations in Europe are investigated in the laboratory and compared against the corresponding behaviour of conventional agricultural films at various stages of their exposure time.     

Vertical proton affinities of CH2O and CH2OH+ in their ground singlet,excited triplet and ionized doublet states

Vertical proton affinities were calculated with closed and open shell direct SCF-MO methods for the ground, excited triplet and ionized doublet states of CH₂O and CH₂OH⁺.The computed gas phase basicity of CH₂O follows the order: CH₂O(¹ A ₁) > CH₂O*(³ A ₁ or ³ A ₂) > CH₂O⁺(² B ₂ or ² B ₁).     

Effect of glutaraldehyde on the activity of some DNA restriction endonucleases

The effect of the bifunctional crosslinking reagent glutaraldehyde on the activity of the restriction enzymes Bam HI,Hind III, EcoRI, and Tthlll I was investigated. The four enzymes exhibited differential sensitivity to inactivation. Tthlll I was the most sensitive, with activity losses occurring at levels of 0.0025% and above.Hind III was the most stable of the four and remained fully active at concentrations as high as 0.075%. Addition of BSA to incubation mixtures generally had a stabilizing effect. Implications of these results for the design of glutaraldehyde-based methods for the immobilization of restriction endonucleases are discussed.     

Peculiarities of the effect of the electronic nature of substituents on the basic properties of aliphatic amines

Changes in the hybrid state of atomic orbitals of nitrogen and p-character of LEP, which occur under the effect of saturated hydrocarbon radicals and polar substituents in aliphatic amines, differ substantially. Therefore, the effect of the both substituents on the basicity constants of amines cannot be described by the single formal type of interaction. The anomalous changes in the basicity in the series of primary, secondary, and tertiary alkylamines, which are discussed in the literature, and the correlations pK _BH+ = f(*) and G _B = f(*) are, in fact, imaginary, because the alkyl radicals at the N atom do not manifest the electron-donor properties.     

Hydrolysis of 1,2-disubstituted imidazolines in aqueous media

The kinetics of hydrolysis of 1,2-disubstituted imidazolines in aqueous media was studied (pH 2.0—12.5, T = 25—90 °C) by UV spectroscopy. The hydrolysis products were identified. The introduction of a branched substituent into position 2 of the imidazoline ring increases the hydrolytic stability of the compounds. The effect of the pH on the hydrolysis rate of imidazolines is discussed.     

Components of <Emphasis Type="Italic">Artemisia pontica</Emphasis>

Chemical components from the aerial part of the Kazakhstan population of Artemisia pontica, from which the rarely encountered flavonoids 7-O-methyl- and 4′,7-di-O-methyl-esters of apigenin were isolated for the first time, were identified. The complete chemical composition of the essential oil was established using GC-MS.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 143–145, March–April, 2005.     

Proton magnetic relaxation study of water orientation around I− and Li+

Proton relaxation time measurements are performed for 6m aqueous solutions of⁷LiI and⁶LiI in D₂O containing small amounts of H₂O. The measurements are done at low temperatures and yield maxima of the relaxation rate plotted against 1/T. From the maxima of the relaxation rates, proteon-I^– and proton-Li⁺ distances in the first coordination sphere of the ions are determined, and from the knowledge of the ion-water oxygen distance it is shown that for iodide a somewhat broadened H-bonded configuration is valid and that for Li⁺ the electric dipole orientation deviates from the radial direction. In order to test the reliability of the method a proton-¹²⁷I interaction study is also performed in KI solution in glycerol. The I-H distance obtained is in satisfactory agreement with that found in the aqueous system.