Low power upconversion using MLCT sensitizers

Selective low energy excitation of the metal-to-ligand charge transfer (MLCT) transition in [Ru(dmb)(3)](2+)(dmb = 4,4'-dimethyl-2,2'-bipyridine) in the presence of anthracene or 9,10-diphenylanthracene yields easily visualized upconverted singlet fluorescence resulting from triplet-triplet annihilation at low excitation power.     

Phosphorylthioacetamides in the synthesis of annulated quinoxalines

Diethoxyphosphorylthioacetamide in the reaction with 2,3-dichloroquinoxaline acted as a thionating reagent, giving diethoxyphosphorylacetonitrile and 2-chloro-3-[(3-chloro-2-quinoxalinyl)thio]quinoxaline. Reactions of phosphorylthioacetamides with N-methylquinoxalinium iodide in alcohol media in the presence of a base proceeded stereoselectively to afford cis-3-phosphoryl-1,3,3a,4,9,9a-hexahydro-2H-pyrrolo[2,3-b]quinoxaline-2-thiones. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1010–1013, May, 2007.     

Calorimetric studies of the interactions between micelle-forming and bilayer-forming amphiphiles

We develop a theoretical basis for detailed investigations of mixed aqueous solutions of amphiphiles by high resolution titration calorimetry (ITC). We review the phenomenology of phase behavior of these systems and formulate the questions addressed in thermodynamic studies. Based on the equations obtained, we introduce a general scheme of calorimetric measurements allowing to characterize comprehensively the energetics of the mixtures. We discuss the results of previous studies in relation to this scheme.     

Interaction of a low-pressure gas flame and heterogeneous catalytic processes on the reactor surface

Conclusions (1) It was shown that the Semenov theory in various modes of chain termination quantitatively describes oxyhydrogen combustion near the first ignition limit with allowance for the interaction between the flame and the catalytic processes on the reactor wall. (2) Numerical modeling of oxyhydrogen ignition in the diffusion-controlled chain-termination mode detected the dependence of the rate “constant” for heterogeneous chain initiation on the model of the reaction in the gas. (3) For the first time, the change in the specific rate of heterogeneous chain initiation during a single ignition was determined. (4) method for controlling the low-pressure flame mode by affecting tubes far from the reactor was proposed and applied. Original Russian Text ? E.N. Aleksandrov, S.N. Kozlov, N.M. Kuznetsov, 2006, published in Doklady Akademii Nauk, 2006, Vol. 407, No. 5, pp. 630–633. Presented by Academician A.E. Shilov October 5, 2005     

Planar oscillations and dissipative heating of viscoelastic plates with a piezoeffect

Planar oscillations of thin piezoplates are important within the context of using this type of piezoelements as resonator frequency filters, frequency stabilizers, elements of piezotransformers, and other technological devices. In the publications currently known one usually considers piezoplates with elastic material behavior and linear governing equations. By their mechanical nature, however, a number of piezoelements, particularly piezoceramics, are viscoelastic, which, depending on the loading conditions, can lead to substantial dissipative heating of the piezoelement and confine its operation [3]. The use of piezopolymers and their composites raises particularly important issues of dissipative heating. At the present time the behavior of a piezoelement including heating can be described by the theory of thermoelectroviscoelasticity (TEVE) [2, 3], including the interaction between electromechanical and thermal fields. The complexity of TEVE problems leads to the necessity of using numerical methods to solve them, with the finite element method (FEM) being widely used in recent years. The present study is devoted to stating and solving TEVE problems concerning thin piezoceramic plates by the FEM. We treat a thin piezoceramic plate, confined by an arbitrary contour L and polarized across its thickness. A harmonic potential difference e^it is supplied to electrodes located on the smooth boundaries of the plate. Convective heat exchange with the surrounding media of temperatures T _k ^s and T^s is implemented at the contour surfaces and boundaries free of electrodes. The heat transfer coefficients equal, respectively, _k ^T and ^T. The initial plate temperature is T₀. The smooth boundary are free of mechanical loading. The mechanical forces at the contour surfaces are distributed symmetrically with respect to the mean plane of the plate.S. P. Timoshenko Institute of Mechanics, Ukrainian Academy of Sciences, Kiev (Ukraine). Translated from Prikladnaya Mekhanika, Vol. 30, No. 2, pp. 69–76, February 1994.     

1-Adamantanecarboxylic Acid Esters of Certain Terpenols, Sterols, and Plant Phenols

Esters 1b-15b were prepared from cetyl alcohol 1a, terpenols 2a-6a, sterols 7a-10a, plant phenols 11a-13a, and alcohols 14a-15a by reaction with 1-adamantanecarboxylic acid chloride in the presence of pyridine.     

Kinetics of Addition of Alcohols to 3-Aroyl-2,4-dihydro-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones

The kinetics of the reaction of 3-aroyl-2,4-dihydro-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with aliphatic alcohols in toluene at 25°C were studied by spectrophotometry. The effects of electronic and steric factors in the nucleophile and substrate were estimated by treatment of the kinetic results by the Hammett and Taft equations.     

Synthesis of 1,4,7,7-tetramethylbicyclo[2.2.1]hept-exo-2-ylacylamines

A procedure has been developed for the selective preparation of 2-methylisoborneol by the action of methyllithium on camphane. It has been shown that the interaction of 2-methylisoborneol with aceto- and benzonitriles in the presence of sulfuric acid gives, as the result of a rearrangement of the carbon skeleton, high yields of the corresponding 1,4,7,7-tetramethylbicyclo[2.2.1]hept-exo-2-ylacylamines, which possess an anticataleptic action.Institute of Physical Organic Chemistry, Belarus Academy of Sciences, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 719–723, November–December, 1994.     

Frequency Characteristics of a Spatially-Confined Electrochemical Cell under Conditions of Convective Diffusion

A theory for the transfer function of an electrochemical cell under conditions of convective diffusion is constructed. The variational principle for the integration of the convective-diffusion equation is developed, which reduces the problem solution to selecting adequate trial functions. With the diffusion frequency exceeded, the decay in the frequency dependence of the transfer function is defined by the system geometry. At a certain balance between parameters of the electrode system the frequency dependence of the transfer function can be strictly analytical, i.e. of the ^–1 type.     

Reactions of potassium dibenzo-18-crown-6 pentacyanocobaltate(II) with some lewis bases

ESR has been applied to the interactions of [K(DBC)]₃[Co(CN)₅], in which DBC is dibenzo-18-crown-6, in methanol solution with triphenylphosphine, pyridine, and triethylamine. The ESR spectra are described for the paramagnetic [(NC)₅CoB]^3– adducts, where B is triphenylphosphine or pyridine.Translated from Teoreticheskaya i Éxperimental'naya Khimiya, Vol. 25, No. 2, pp. 234–237, March–April, 1989.