Code control for parametric models of induction heaters

In this paper, we describe our approach to building controllable models of induction heaters. Parameters of equivalent circuits of aluminum heating inductors include certain components tied to secondary elements. As long as metal properties are subject to change during the heating process, resistive and reactive parts of equivalent circuits should be taken into account. Adjustable resistive components have rarely been used in circuit models. To control equivalent resistive two-terminal parts, we offer pulse code control of impedance-changing switches. Controlling switching time in models with series, parallel, and mixed connection provides required softness of resistive conductivity change. Control characteristics of current and voltage were obtained with use of a simulator. As the result of our numerical experiment, the set of operating parameters for an induction device was determined.

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Characterization of Self-Heating Process in GaN-Based HEMTs

Electronics ◽

10.3390/electronics9081305 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1305 ◽

Cited By ~ 1

Author(s):

Daniel Gryglewski ◽

Wojciech Wojtasiak ◽

Eliana Kamińska ◽

Anna Piotrowska

Keyword(s):

Communication Systems ◽

Accurate Determination ◽

Heating Process ◽

Equivalent Circuits ◽

High Electron ◽

Thermal Impedance ◽

Self Heating ◽

Gan Hemt

Thermal characterization of modern microwave power transistors such as high electron-mobility transistors based on gallium nitride (GaN-based HEMTs) is a critical challenge for the development of high-performance new generation wireless communication systems (LTE-A, 5G) and advanced radars (active electronically scanned array (AESA)). This is especially true for systems operating with variable-envelope signals where accurate determination of self-heating effects resulting from strong- and fast-changing power dissipated inside transistor is crucial. In this work, we have developed an advanced measurement system based on DeltaVGS method with implemented software enabling accurate determination of device channel temperature and thermal resistance. The methodology accounts for MIL-STD-750-3 standard but takes into account appropriate specific bias and timing conditions. Three types of GaN-based HEMTs were taken into consideration, namely commercially available GaN-on-SiC (CGH27015F and TGF2023-2-01) and GaN-on-Si (NPT2022) devices, as well as model GaN-on-GaN HEMT (T8). Their characteristics of thermal impedance, thermal time constants and thermal equivalent circuits were presented. Knowledge of thermal equivalent circuits and electro–thermal models can lead to improved design of GaN HEMT high-power amplifiers with account of instantaneous temperature variations for systems using variable-envelope signals. It can also expand their range of application.

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Investigation of the Heating Characteristics in a Reheating Furnace with Pulse Combustion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.291-294.1834 ◽

2013 ◽

Vol 291-294 ◽

pp. 1834-1838

Author(s):

Jia Qun Xia ◽

Hu Ping Li

Keyword(s):

Heat Balance ◽

Combustion Products ◽

Experimental Results ◽

Flue Gases ◽

Heating Process ◽

Operating Parameters ◽

Theoretical Computation ◽

Reheating Furnace ◽

Heat Efficiency ◽

Pulse Combustion

This paper presents a theoretical and experimental analysis of a pulse combustion in reheating furnace. Measurements of the composition content on flue gases and heat balance tests were carried out for operating parameters in reheating furnace. Experimental results show an intensive and efficient heating process. An attempt was made to perform theoretical computation of composition content in the reheating furnace. Satisfactory agreement between calculations and experimental results was found in certain regions. Discrepancies might be caused by sample of the combustion products which were assumed to be uniform distribution out of the reheating furnace. The results show that the pulse combustion has comparatively large influence upon both combustion and heat efficiency in a reheating furnace.

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Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072666 ◽

1973 ◽

Vol 31 ◽

pp. 444-445

Author(s):

P.J. Killingworth ◽

M. Warren

Keyword(s):

Electron Beam ◽

Organic Materials ◽

Operating Parameters ◽

Low Density ◽

Beam Diameter ◽

Incident Electron Beam ◽

Specimen Material ◽

Voltage Compensation ◽

Selection Of ◽

Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

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Electron sources: Past, present, and future

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149659 ◽

1993 ◽

Vol 51 ◽

pp. 764-765

Author(s):

David C Joy

Keyword(s):

Glass Tube ◽

Source Size ◽

Electron Gun ◽

Operating Parameters ◽

Operational Parameters ◽

Electron Sources ◽

Difficult Decision ◽

Probe Size ◽

Wide Range ◽

Overall Performance

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.

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Using stead-state visual evoked potentials to measure attentional switching time

PsycEXTRA Dataset ◽

10.1037/e536982012-583 ◽

1997 ◽

Author(s):

Stephen Morgan ◽

Jon Hansen ◽

Steven Hillyard

Keyword(s):

Evoked Potentials ◽

Visual Evoked Potentials ◽

Switching Time ◽

Attentional Switching ◽

Visual Evoked

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Non-Linear Dynamics of Cardiovascular Variability Signals

Methods of Information in Medicine ◽

10.1055/s-0038-1634981 ◽

1994 ◽

Vol 33 (01) ◽

pp. 81-84 ◽

Cited By ~ 14

Author(s):

S. Cerutti ◽

S. Guzzetti ◽

R. Parola ◽

M.G. Signorini

Keyword(s):

Dimensional Space ◽

Severe Heart Failure ◽

Parametric Models ◽

Deterministic Systems ◽

Finite Dimensional ◽

Return Maps ◽

Pathological Conditions ◽

Non Linear ◽

Space State

Abstract:Long-term regulation of beat-to-beat variability involves several different kinds of controls. A linear approach performed by parametric models enhances the short-term regulation of the autonomic nervous system. Some non-linear long-term regulation can be assessed by the chaotic deterministic approach applied to the beat-to-beat variability of the discrete RR-interval series, extracted from the ECG. For chaotic deterministic systems, trajectories of the state vector describe a strange attractor characterized by a fractal of dimension D. Signals are supposed to be generated by a deterministic and finite dimensional but non-linear dynamic system with trajectories in a multi-dimensional space-state. We estimated the fractal dimension through the Grassberger and Procaccia algorithm and Self-Similarity approaches of the 24-h heart-rate variability (HRV) signal in different physiological and pathological conditions such as severe heart failure, or after heart transplantation. State-space representations through Return Maps are also obtained. Differences between physiological and pathological cases have been assessed and generally a decrease in the system complexity is correlated to pathological conditions.

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