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91.
The results of single-probe studies of thick and thin silicon p-n junctions are described. The electric fields in a diode with a p+-n junction and in a stabilitron with a p-n junction in the forward and reverse directions are studied. Measurements are made at various currents and temperatures. The p-n junctions are analyzed on the basis of the probe measurements. 相似文献
92.
Dorin Ieşan 《Meccanica》1986,21(2):94-96
Summary A problem of Truesdell concerning the theory of torsion is studied in the framework of micropolar elasticity.
Sommario Un problema di Truesdell relativo alla teoria di torsione viene studiato nell'ambito dell'elasticità micropolare.相似文献
93.
Summary The linear theory of thermoelasticity established by Green and Lindsay with the help of an entropy production inequality proposed by Green and Laws is generalized to the case of a homogeneous micropolar continuum. The basic equations are derived using invariance conditions under superposed rigid body motions.
Sommario La teoria lineare della termoelasticità stabilita da Green e Lindsay sulla base della disuguaglianza della produzione dell'entropia proposta da Green e Laws è generalizzata al caso di un continuo micropolare omogeneo. Le equazioni fondamentali vengono derivate usando condizioni di invarianza rispetto a moti rigidi sovrapposti.相似文献
94.
Dorin Lelea 《Heat and Mass Transfer》2007,44(1):33-41
In this paper, the conjugate heat transfer of the water flow inside the microtube (D
i/D
o = 0.1/03 and 0.1/0.5 mm) was investigated. The laminar regime was considered with Re up to 200, input heat transfer rate of Q
0 = 0.1 W and variable thermophysical properties of the water. Two different cases of the partial joule heating were considered
for the tube wall. In the first case the tube wall was heated near the inlet of the tube (upstream heating) while, in the
second case, the outlet portion of the wall was heated (downstream heating). In order to investigate the influence of the
tube material on the heat transfer behavior and limits of the axial conduction inside the wall, three different tube wall
materials were considered, stainless steel (k = 15.9 W/m K), silicon (k = 189 W/m K) and copper (k = 398 W/m K). 相似文献
95.
The additive manufacturing process is one of the technical domains that has had a sustained development in recent decades. The designers’ attention to equipment and materials for 3D printing has been focused on this type of process. The paper presents a comparison between the results of the bending tests and those of the simulation of the same type of stress applied on 3D-printed PLA and PLA–glass structures. The comparison of the results shows that they are close, and the simulation process can be applied with confidence for the streamline of filament consumption, with direct consequences on the volume and weight of additive manufactured structures. The paper determines whether the theories and concepts valid in the strength of materials can be applied to the additive manufacturing pieces. Thus, the study shows that the geometry of the cross-section, by its shape (circular or elliptical) and type (solid or ring shaped), influences the strength properties of 3D-printed structures. The use of simulation will allow a significant shortening of the design time of the new structures. Moreover, the simulation process was applied with good results on 3D-printed structures in which two types of filaments were used for a single piece (structure). 相似文献
96.
We introduce a duality for affine iterated function systems (AIFS) which is naturally motivated by group duality in the context
of traditional harmonic analysis. Our affine systems yield fractals defined by iteration of contractive affine mappings. We
build a duality for such systems by scaling in two directions: fractals in the small by contractive iterations, and fractals
in the large by recursion involving iteration of an expansive matrix. By a fractal in the small we mean a compact attractor
X supporting Hutchinson’s canonical measure μ, and we ask when μ is a spectral measure, i.e., when the Hilbert space has an orthonormal basis (ONB) of exponentials . We further introduce a Fourier duality using a matched pair of such affine systems. Using next certain extreme cycles,
and positive powers of the expansive matrix we build fractals in the large which are modeled on lacunary Fourier series and
which serve as spectra for X. Our two main results offer simple geometric conditions allowing us to decide when the fractal in the large is a spectrum
for X. Our results in turn are illustrated with concrete Sierpinski like fractals in dimensions 2 and 3.
Research supported in part by the National Science Foundation DMS 0457491. 相似文献
97.
In this paper we prove the existence of a deformation transforming an arbitrary open set into the ball, which has the following properties: it keeps constant the measure, the kth eigenvalue of Laplace–Dirichlet operator is continuous from the left and the first eigenvalue is decreasing. The deformation is given by a sequence of continuous Steiner symmetrizations, and the behavior of the eigenvalues is related to the stability of the Dirichlet problem. 相似文献
98.
Ordered mesoporous SiC with high specific surface area (650-800 m(2) g(-1)) and well ordered pore structure was obtained via nanocasting of polycarbosilanes into SBA-15 and subsequent conversion of the polymer at 1300 degrees C. 相似文献
99.
Dorin Bucur Eduard Feireisl Šárka Nečasová 《Journal of Mathematical Fluid Mechanics》2008,10(4):554-568
We consider a stationary Navier–Stokes flow in a bounded domain supplemented with the complete slip boundary conditions. Assuming
the boundary of the domain is formed by a family of unidirectional asperities, whose amplitude as well as frequency is proportional
to a small parameter ε, we shall show that in the asymptotic limit the motion of the fluid is governed by the same system
of the Navier–Stokes equations, however, the limit boundary conditions are different. Specifically, the resulting boundary
conditions prevent the fluid from slipping in the direction of asperities, while the motion in the orthogonal direction is
allowed without any constraint.
The work of Š. N. supported by Grant IAA100190505 of GA ASCR in the framework of the general research programme of the Academy
of Sciences of the Czech Republic, Institutional Research Plan AV0Z10190503. 相似文献
100.
Dorin Bucur Alessandro Giacomini Paola Trebeschi 《Proceedings of the American Mathematical Society》2008,136(7):2535-2545
For , we prove that all the functions of satisfy the Whitney property; i.e., if is such that (in the sense of capacity) on a connected set , then is constant on .