New approach to the design of thyristor and transistor switching circuits

1987 ◽  
Vol 134 (2) ◽  
pp. 61 ◽  
Author(s):  
K. Mikołajuk ◽  
W.S. Kropacz
2009 ◽  
Vol 18 (07) ◽  
pp. 1205-1225 ◽  
Author(s):  
YEFIM BERKOVICH ◽  
ARIEH SHENKMAN ◽  
SAAD TAPUCHI

In this paper a novel method for circuit analysis is proposed. It is based on using symbolic analysis in matrix form, which is especially appropriate for repetitive similar calculations of the same circuit. This method, which applies hyper-complex numbers (hypernions), was first developed by the authors for analyzing the non-sinusoidal operation of electrical circuits. Now, the method has been extended to the analysis of electronic/switching circuits in which the sources and/or the parameters are step-wisely changed as a result of switching. Such circuits are common in different kinds of DC-DC converters (such as Buck, Boost, Cuk, etc.). The proposed method gives a new approach to the analysis of the above circuits by opening the possibility of treating them in a general-analytical form, just like in regular electrical circuits having a constant configuration and constant parameters. The computation of such kinds of circuits by using the proposed method becomes very simple, since the circuit does not have to be analyzed many times, each time for a different configuration, but all at once by performing a parallel computation. The theoretical presentation is accompanied by numerical examples.


1995 ◽  
Vol 05 (03) ◽  
pp. 317-336 ◽  
Author(s):  
N. FEMIA ◽  
G. SPAGNUOLO ◽  
V. TUCCI

The use of Interval Analysis for numerical simulation of power electronic circuits is discussed in this paper. It is shown that Interval Analysis is an optimal tool for such kind of applications since switching circuits operate upon sequences of time intervals bounded by instants that are zeros of non-linear non-monotonic functions. The main advantages offered by Interval Analysis are pointed out in the context of a new approach proposed to solve the problems of steady-state and transient analysis. In particular, it is shown that for steady-state analysis a robust and fast IA-based method can be adopted which generates a sequence of virtual solutions that converges towards the right steady-state solution within few iterations, without any prior knowledge about the mode of operation of the circuit. Some examples of applications are proposed, including chaos, subharmonics and circuit collapse.


1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.


Author(s):  
V. Mizuhira ◽  
Y. Futaesaku

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.


Author(s):  
K. Chien ◽  
R. Van de Velde ◽  
I.P. Shintaku ◽  
A.F. Sassoon

Immunoelectron microscopy of neoplastic lymphoma cells is valuable for precise localization of surface antigens and identification of cell types. We have developed a new approach in which the immunohistochemical staining can be evaluated prior to embedding for EM and desired area subsequently selected for ultrathin sectioning.A freshly prepared lymphoma cell suspension is spun onto polylysine hydrobromide- coated glass slides by cytocentrifugation and immediately fixed without air drying in polylysine paraformaldehyde (PLP) fixative. After rinsing in PBS, slides are stained by a 3-step immunoperoxidase method. Cell monolayer is then fixed in buffered 3% glutaraldehyde prior to DAB reaction. After the DAB reaction step, wet monolayers can be examined under LM for presence of brown reaction product and selected monolayers then processed by routine methods for EM and embedded with the Chien Re-embedding Mold. After the polymerization, the epoxy blocks are easily separated from the glass slides by heatingon a 100°C hot plate for 20 seconds.


Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.


Author(s):  
Arthur V. Jones

With the introduction of field-emission sources and “immersion-type” objective lenses, the resolution obtainable with modern scanning electron microscopes is approaching that obtainable in STEM and TEM-but only with specific types of specimens. Bulk specimens still suffer from the restrictions imposed by internal scattering and the need to be conducting. Advances in coating techniques have largely overcome these problems but for a sizeable body of specimens, the restrictions imposed by coating are unacceptable.For such specimens, low voltage operation, with its low beam penetration and freedom from charging artifacts, is the method of choice.Unfortunately the technical dificulties in producing an electron beam sufficiently small and of sufficient intensity are considerably greater at low beam energies — so much so that a radical reevaluation of convential design concepts is needed.The probe diameter is usually given by


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