Square wells, quantum wells and ultra-thin metallic films

The eigenvalue equations for the energy of bound states of a particle in a square well are solved, and the exact solutions are obtained, as power series. Accurate analytical approximate solutions are also given. The application of these results in the physics of quantum wells are discussed,especially for ultra-thin metallic films, but also in the case of resonant cavities, heterojunction lasers, revivals and super-revivals.Comment: 21 pages, 3 figure

Shape- and topology-dependent heat capacity of few-particle systems

Thermal properties of few-fermion (n < 5) systems are investigated. The dependence of the heat capacity on the topology and shape of the cavity containing the particles is analyzed. It is found that the maximum of the heat capacity, occuring at low T, discussed recently by Toutounji for a system with n = 1 fermions, is even more visible for n = 2, but fades away for n = 3 and 4. For large T, the classical behavior is obtained; however, when T -> 0, the heat capacity tends to zero exponentially, not linearly, as in macroscopic and even mesoscopic systems. The physical relevance of these results is discussed

Siewert solutions of transcendental equations, generalized Lambert functions and physical applications

We review the exact solutions of several transcendental equations, obtained by Siewert and his co-workers, in the '70s. Some of them are expressed in terms of the generalized Lambert functions, recently studied by Mez\"o, Baricz and Mugnaini. For some others, precise analytical approximations are obtained. In two cases, the asymptotic form of Siewert's solutions are written as Wright omega functions.Comment: 17 pages, 5 figure

Issues SMEs Face Within the Internationalisation Process

The paper presents the correlation between different variables and internationalisation, such as: the size of the company, the activity field, the level of innovation. It also emphasizes the barriers the SMEs face in the process. In the end of the paper, one presents some of the solutions proposed in order to sustain the SMEs overcome these barriers.SMEs, internationalisation, innovation, success.

Chloroplast to chromoplast transition in tomato fruit: spectral confocalmicroscopy analyses of carotenoids and chlorophylls in isolated plastids and time-lapse recording on intact live tissue

During evolution, chromoplasts have emerged as plastid structures which accumulate pigments to facilitate flower pollination and seed dispersal of fleshy fruit. There is good evidence that chromoplasts derive from chloroplasts (Pyke, 2007), even if nobody has ever recorded this transition. Structural changes occurring during chloroplast to chromoplast transition have been described in fleshy fruit by electron microscopy primarily in tomato (Rosso, 1968; Harris and Spurr, 1969) and in bell pepper (Spurr and Harris, 1968). During the differentiation process controlled breakdown of chlorophyll and disruption of the thylakoid membrane occurred, concomitant with an increase in the aggregation of carotenoids. Different carotenoid-accumulating bodies have been described, including plastoglobules, crystalline and microfibrillar structures, and internal membranous structures

THE INFLUENCE OF SPARE PARTS EXPENSES ON PRODUCTION COSTS WITH THE PREPARATION OF THE JIU VALLEY COAL

The activity of supply and that of exploitation of the spare parts from the composition of the equipments that realize the preparation of the Jiu Valley coal influence its production costs. In this respect, this paper deals with, during some periods of time, initially determined, the specific costs of the spare parts for the sieves, pumps and pipes, equipments, and also auxiliary equipments that are part of the endowment of the Exploitation of the Jiu Valley coal preparation. The results got can be used to rank and determine the causes which determine the high expenses of some spare parts categories as well as the possibility to reduce the production costs within E.P.C.V.J