Crystal structure and nontrivial magnetic properties of CuII binuclear complex based on 4-methyl-2,6-bis{[2-(4,6-dimethyl-pyrimidin-2-yl)hydrazono]methyl}phenol

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Electron–phonon effect on the ground-state binding energy of hydrogenic impurity in quantum-well wire in presence of an electric field

The hydrogenic impurity binding energy in rectangular quantum well wire including both barriers of finite height and an applied electric field are studied. The polaron effects on the ground-state binding energy in electric field are investigated by means of Landau-Pekar variation technique. The results for the binding energy as well as polaronic correction are obtained as a function of the size of the wire, the applied electric field and the position of the impurity. Our calculations are compared with previous results in quantum wires of comparable dimensions.     

The polaron effect on the binding energy of a shallow donor impurity in quantum-well wires in an electric field

Using a variational technique, the effect of electron-longitudinal optical (LO) phonon interaction on the ground and the first few excited states of a hydrogenic impurity in a semiconductor quantum wire of rectangular cross section under an external electric field is studied theoretically for the impurity atom doped at various positions. The results for the binding energy as well as polaronic correction are obtained as a function of the size of the wire, the applied uniform electric field and the position of the impurity. It is found that the presence of optical phonons changes significantly the values of the impurity binding energies of the system. Taking into account the electron–LO phonon interaction the 1s→2p_y and 1s→2p_z transition energies are calculated as a function of applied electric field for different impurity positions.     

Nonuniqueness in a Free Boundary Problem from Combustion

We study a parabolic free boundary problem with a fixed gradient condition which serves as a simplified model for the propagation of premixed equidiffusional flames. We give a rigorous justification of an example due to J.L. Vázquez that the initial data in the form of two circular humps leads to the nonuniqueness of limit solutions if the supports of the humps touch at the time of their maximal expansion. A. Petrosyan was supported in part by NSF grant DMS-0701015. N.K. Yip was supported in part by NSF grant DMS-0406033.     

A minimum problem with free boundary for a degenerate quasilinear operator

In this paper we prove regularity (near flat points) of the free boundary 0\}\cap\Omega$" align="middle" border="0"> in the Alt-Caffarelli type minimum problem for the p-Laplace operator: 0\}}\right)dx\rightarrow \min\qquad (1 Received: 3 June 2003, Accepted: 9 June 2004, Published online: 8 February 2005Mathematics Subject Classification (2000): 35R35, 35J60The first author is partially supported by NSF Grant DMS-0202801 and NSF CAREER Grant DMS-0239771     

Regularity of a free boundary in parabolic potential theory

We study the regularity of the free boundary in a Stefan-type problem

with no sign assumptions on and the time derivative .

     

Effects of Polymer Binder,Surfactant and film Thickness on pH Sensitivity of Polymer Thick Film Sensors

Measuring the change of the conductivity of a Polyaniline (PANI) film while in contact with a solution is considered to be a costeffective tool for pH sensing. The device consists of a PANI film deposited between two identical electrodes, reducing the number of fabrication steps. To ensure the sensors display an optimum response to solutions of different pH values, it is important to understand the effect of the polymer binder, surfactant and film thickness. The effect of varying the amount of Polyvinyl butyral (PVB) and Hypermer (PS3) on the pH sensitivity of screen printed thick film sensors is reported.     

A free boundary problem for $\infty$–Laplace equation

We consider a free boundary problem for the p-Laplacian describing nonlinear potential flow past a convex profile K with prescribed pressure on the free stream line. The main purpose of this paper is to study the limit as of the classical solutions of the problem above, existing under certain convexity assumptions on a(x). We show, as one can expect, that the limit solves the corresponding potential flow problem for the -Laplacian in a certain weak sense, strong enough however, to guarantee uniqueness. We show also that in the special case the limit is given by the distance function. Received: 10 October 2000 / Accepted: 23 February 2001 / Published online: 19 October 2001     

Electrical and optical properties of chemically deposited conducting glass for SIS solar cells

Thin layers of conducting glass (SnO₂:F) of 3 ohm per square sheet resistance were chemically deposited on borosilicate glass for potential applications in SIS solar cells. The layers exhibit 90% optical transmission at the solar maximum (0.5 μm). In an optical investigation of the conducting glass at room temperature, a direct allowed transition at 4.1 eV was observed. Indirect allowed transition was also observed with an energy gap of 2.65 eV and an assisting phonon of 0.05 eV. These observations were supported by reflectance data obtained by an integrating sphere. A technique of making ohmic contacts with SnO₂:F layers is also described.     

A parabolic almost monotonicity formula

We prove the parabolic counterpart of the almost monotonicity formula of Caffarelli, Jerison and Kening for pairs of functions u _±(x, s) in the strip satisfying