<title>Three-dimensional analysis of a tapered waveguide structure by a doubled-grid finite-differences method</title>

<p>Our work is to create a three-dimensional Simulator (3D) used for the study of the components to low geometry of design, and to determine in the volume structure the potential distributions and densities of free carriers in bias voltage given by solving the system of Poisson and two continuities equations. The initial version can simulate components of lifetime semiconductor. In this study, we make a comparison between the lifetime and relaxation semiconductor in the conduction mode. In order to create a larger Simulator, we'll perform a calculation by varying am bipolar lifetime way to move from lifetime semiconductor to relaxation semiconductor. We consider the case corresponding at two different values of diffusion lifetime τ<sub>0</sub> which is corresponding to a measured lifetime in current transport. The method of resolution consists to linearization of the equations transport by the finite differences method. The algorithm for solving linear and strongly coupled equations deduced from the physical model is the Newton-Raphson. However, in order to allow a better convergence and consequently an improvement of time computing 3D, a method combined, incorporating the Newton algorithm and the Gummel method was developed. PIN diodes are used for test of the simulation model</p>

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In situ investigation of the primary recrystallization of alpha titanium in HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110313 ◽

1978 ◽

Vol 36 (1) ◽

pp. 634-635

Author(s):

S. Naka ◽

R. Penelle ◽

R. Valle

Keyword(s):

Dimensional Analysis ◽

Texture Evolution ◽

Cold Work ◽

Three Dimensional ◽

Primary Recrystallization ◽

Thin Foils ◽

In Situ Investigation ◽

Grain Growth Model ◽

Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

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