Effect of Target Erosion on Properties of Molybdenum Films

Russian Journal of Applied Chemistry - The influence exerted by the profile of the zone in which the target is sputtered on the structure and properties of molybdenum films produced by magnetron...     

Quasi-classical generalized CRF structures

In an earlier paper, we studied manifolds M endowed with a generalized F structure \(\Phi \in \mathrm{End}(TM\oplus T^*M)\), skew-symmetric with respect to the pairing metric, such that \(\Phi ^3+\Phi =0\). Furthermore, if \(\Phi \) is integrable (in some well-defined sense), \(\Phi \) is a generalized CRF structure. In the present paper, we study quasi-classical generalized F and CRF structures, which may be seen as a generalization of the holomorphic Poisson structures (it is well known that the latter may also be defined via generalized geometry). The structures that we study are equivalent to a pair of tensor fields \((A\in \mathrm{End}(TM),\pi \in \wedge ^2TM)\), where \(A^3+A=0\) and some relations between A and \(\pi \) hold. We establish the integrability conditions in terms of \((A,\pi )\). They include the facts that A is a classical CRF structure, \(\pi \) is a Poisson bivector field and \(\mathrm{im}\,A\) is a (non)holonomic Poisson submanifold of \((M,\pi )\). We discuss the case where either \(\mathrm{ker}\,A\) or \(\mathrm{im}\,A\) is tangent to a foliation and, in particular, the case of almost contact manifolds. Finally, we show that the dual bundle of \(\mathrm{im}\,A\) inherits a Lie algebroid structure and we briefly discuss the Poisson cohomology of \(\pi \), including an associated spectral sequence and a Dolbeault type grading.     

Universal regularities of hydraulic fracturing within the framework of the Perkins-Kern-Nordgren model

An algorithm that permits one to find a solution of the Perkins-Kern-Nordgren problem for standard regimes of hydraulic fracturing is suggested. The universal qualitative specifics, of the behavior of a crack is shown; in particular, the asymptotics of crack opening at the tip is found, and it is shown that the character of the crack is determined by the rate of increase or decrease in the crack size. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 3, pp. 149–157, May–June, 1998.     

Dynamic model of liquid motion in a porous medium

A theory which takes account of the role of inertial effects in liquid motion in a porous medium is developed. For a compressible liquid, not only the hydrodynamic equations but also the thermodynamic transfer equation are formulated. The initiation, propagation, and dissipation characteristics of eddy motion are considered. Matching conditions at the interface between the media and boundary conditions are obtained. An approximate formulation of the problem is given, isolating in the porous medium a basic flow region in which the classical Darcy law is valid. As an illustration, weakly perturbed liquid flow in a plane channel with an insert of porous material is investigated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 89–95, November–December, 1978.     

Reduction and submanifolds of generalized complex manifolds

We recall the presentation of the generalized, complex structures by classical tensor fields, while noticing that one has a similar presentation and the same integrability conditions for generalized, paracomplex and subtangent structures. This presentation shows that the generalized, complex, paracomplex and subtangent structures belong to the realm of Poisson geometry. Then, we prove geometric reduction theorems of Marsden-Ratiu and Marsden-Weinstein type for the mentioned generalized structures and give the characterization of the submanifolds that inherit an induced structure via the corresponding classical tensor fields.     

Validated LC‐MS/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study

A sensitive high‐performance liquid chromatography–tandem mass spectrometric (HPLC‐MS/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2 mL aliquots of alkalinized plasma by a single solvent extraction into hexane : dichloromethane. Reversed‐phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10 mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4 mL/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were m/z 489.3 → 312.2 for vardenafil and m/z 309.2 → 281.0 for alprazolam. The assay was linear over the concentration range of 0.2–100 ng/mL, with correlation coefficients ≥0.995. The intra‐ and inter‐day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2 ng/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study. Copyright © 2009 John Wiley & Sons, Ltd.