scholarly journals Voltage Followers for the Design of Sallen-Key Active Rc-Filters

2021 ◽  
Author(s):  
Vladislav Chumakov ◽  
Ilya Pakhomov ◽  
Alexey Titov ◽  
Nikolay Butyrlagin ◽  
Nikolay Prokopenko
Keyword(s):  
Low Temperature ◽  
Neutron Flux ◽  
Computer Modeling ◽  
Cryogenic Temperatures ◽  
Unity Gain ◽  
Radiation Resistant

In this paper consider the circuitry of voltage followers (VF) with unity-gain, intended for practical use in active Sallen-Key RC-filters (LPF, HPF, BPF, RF). The results of research and computer modeling of radiation-resistant and low-temperature VF in the LTSpice environment on models of CJFET transistors operating under the influence of neutron flux up to 10e14 n/cm2 and cryogenic temperatures up to -197°C are presented.

STATUS OF THE RADAPPERTIZATION OF MEATS1

1974 ◽  
Vol 37 (2) ◽  
pp. 86-93 ◽  
Author(s):  
D. B. Rowley ◽  
Abe Anellis ◽  
E. Wierbicki ◽  
A. W. Baker
Keyword(s):  
Sodium Chloride ◽  
Low Temperature ◽  
Proteolytic Enzymes ◽  
Model Systems ◽  
Human Consumption ◽  
Cured Meats ◽  
Radiation Resistant ◽  
Animal Feeding ◽  
Resistant Strains ◽  
Microbiological Data

Considerable progress has been made toward development of highly acceptable radappertized meats through application of a heat treatment to an internal temperature of 65–80 C to inactivate proteolytic enzymes before irradiation, low temperature (−30 ± 10 C) of the food during irradiation, and addition of low levels of tripolyphosphate and sodium chloride. To assure that radappertized meats are free of potential pathogens and spoilage microorganisms they are given a minimum radiation dose (MRD) computed to effect a 12 log cycle reduction in the most radiation resistant strains of Clostridium botulinum spores. Inoculated pack studies are carried out to obtain the specific microbiological data required for computing the MRD. Cured meats normally have a lower MRD than uncured meats. In model systems concentrations of sodium chloride (NaCl) up to 4.0% (w/v) present during irradiation had no effect on radiation resistance, but NaCl did inhibit recovery of irradiated spores. A mixture of salts (4.0% NaCl, 30 ppm NaNO2 500 ppm NaNO3) had essentially the same effect as NaCl alone. Of 11 genera of vegetative cells examined, Micrococcs radiodurans and Streptococcus faecium were shown to be the most resistant to low-temperature gamma irradiation. Before the radappertization process can be established commercially it is necessary to provide proof that products so treated are safe for human consumption. An intensive animal feeding study of radappertized (4.7–7.1 Mrads) beef was initiated in 1971 and is expected to be completed in 1976.

Static Performance of SiGe HBTs at Low Temperature

2014 ◽  
Vol 666 ◽  
pp. 59-63
Author(s):  
Maya Lakhdara ◽  
Saϊda Latreche ◽  
Christian Gontrand
Keyword(s):  
Low Temperature ◽  
Heterojunction Bipolar Transistors ◽  
High Performance ◽  
Industrial Process ◽  
Bipolar Transistors ◽  
Fundamental Aspect ◽  
Cryogenic Temperatures ◽  
Sige Hbt ◽  
Static Performance ◽  
The Impact

—This paper analyse is the impact of cryogenic temperatures for SiGe Heterojunction Bipolar Transistors (HBTs) base, realised in BiCMOS9 0.13μm industrial process. The use of these components in microwaves applications exposed to various temperatures is fundamental aspect to predict in precise way its electric characteristics. This paper investigates the temperature dependence from (170 K to 300 K) of DC, for NPN SiGe heterojunction bipolar transistors (HBTs) and notably modeling high performance Si/SiGe HBT for telecommunication and radar detection (>0.5THz) in low temperature (cryogenic temperature).

scholarly journals Analysis of argon isotope separation by low temperature adsorption

2020 ◽  
Vol 324 ◽  
pp. 01006
Author(s):  
Vitaly L. Bondarenko ◽  
Maxim Y. Kupriyanov ◽  
Artem I. Verkhovnyi
Keyword(s):  
Low Temperature ◽  
Adsorption Isotherms ◽  
Equations Of State ◽  
Isotope Separation ◽  
Critical Parameters ◽  
Cryogenic Temperatures ◽  
Isotope Mixture ◽  
Argon Isotopes ◽  
Argon Isotope ◽  
Analytical Expressions

In this work, the estimated calculated values of the critical parameters of argon isotopes 36Ar, 38Ar, 40Ar and the corresponding values of the constants of the Van der Waals, Redlich-Kwong and Peng-Robinson equations of state are obtained. The data obtained make it possible to calculate the adsorption isotherms of argon isotopes on microporous adsorbents. The technique proposed for obtaining analytical expressions for the adsorption isotherms of argon isotopes at cryogenic temperatures makes it possible to estimate the degree of influence of the pressure of the isotope mixture and its composition on the mixture separations coefficients.

scholarly journals High accuracy computational methods for behavioral modeling of thick-film resistors at cryogenic temperatures

2016 ◽  
Vol 34 (1) ◽  
pp. 212-225 ◽  
Author(s):  
Franciszek Balik ◽  
Andrzej Dziedzic
Keyword(s):  
Low Temperature ◽  
Thick Film ◽  
Behavioral Modeling ◽  
Cryogenic Temperatures ◽  
Exact Methods ◽  
Modeling Errors ◽  
Multidimensional Approximation ◽  
Computational Procedures ◽  
Freezing Liquid ◽  
Methods Of Calculations

AbstractThe aim of this work was to elaborate two-dimensional behavioral modeling method of thick-film resistors working in low-temperature conditions. The investigated resistors (made from 5 various resistive inks: 10 resistor coupons, each with 36 resistors with various dimensions), were measured automatically in a cryostat system. The low temperature was achieved in a nitrogen-helium continuous-flow cryostat. For nitrogen used as a freezing liquid the minimal temperature possible to achieve was equal to −195.85 °C (77.3 K). Mathematical model in the form of a multiplication of two polynomials was elaborated based on the above mentioned measurements. The first polynomial approximated temperature behavior of the normalized resistance, while the second one described the dependence of resistance on planar resistors dimensions. Special computational procedures for multidimensional approximation purpose were elaborated. It was shown that proper approximation polynomials and sufficiently exact methods of calculations ensure acceptable modeling errors.

Description of a High-Efficiency Floating-Piston Expander for a Miniature Cryocooler

2002 ◽  
Author(s):  
J. L. Smith ◽  
J. G. Brisson ◽  
M. J. Traum ◽  
C. Hannon ◽  
J. Gerstmann
Keyword(s):  
Low Temperature ◽  
Active Control ◽  
High Efficiency ◽  
Working Fluid ◽  
Cryogenic Temperatures ◽  
Helium Flow ◽  
Variable Volume ◽  
System Miniaturization ◽  
Operating Points ◽  
Novel Design

A cryogenic expander employing low-temperature helium is under development. This expander employs a floating piston operating between a warm variable volume and a cold variable volume to expand the working fluid. The piston’s position is dynamically regulated through an active control routine that actuates electromechanical valves. These valves control helium flow in and out of the variable volumes. Throttling through the warm-end valves regulates the piston’s velocity. The cold-end valves, operating at cryogenic temperatures, are of novel design to achieve system miniaturization and high efficiency at range of operating points.

scholarly journals Computer Modeling of Displacement Cascades in Beryllium Irradiated with Intensive Neutron Flux

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
T. Troev ◽  
N. Nankov ◽  
L. Petrov ◽  
E. Popov
Keyword(s):  
Neutron Flux ◽  
Fast Neutron ◽  
Computer Modeling ◽  
Computer Simulations ◽  
Neutron Fluence ◽  
Fast Neutrons ◽  
Radiation Defects ◽  
Helium Concentration ◽  
Vacancy Clusters ◽  
Displacement Cascades

Computer simulations of the radiation defects created in beryllium irradiated by fast neutrons (E>0.1 MeV) using the Geant4 and SRIM packages were carried out. The atom cascade displacements in Be at a neutron fluence of 1.6×1020 n/cm2 were determined to be 0.06 dpa and the helium concentration was calculated to be 168 appm. The concentration of 6Li has been estimated to be 5% in comparison to the He concentration. Nanoscale calculations were done in 30×30×30 nm cube of fast neutron-irradiated Be. A correlation between the Be primary knock-on atom (PKA) energies and the damage cascades has been established. The final defect distributions of single vacancies, divacancies, and small vacancy clusters were examined. Our results indicate that the damages caused by He atoms are about 3 times less than damages caused by Be primary knock-on atoms (PKAs).

Computer modeling in low temperature geochemistry

1979 ◽  
Vol 17 (4) ◽  
pp. 850 ◽  
Author(s):  
Robert W. Potter
Keyword(s):  
Low Temperature ◽  
Computer Modeling
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