Gradient Coils Temperature Controller in a Gradient System for MR Tomography

2007 ◽  
Author(s):  
Karel Bartusek ◽  
Zdenek Dokoupil ◽  
Eva Gescheidtova ◽  
Zdenek Smekal
Keyword(s):  
Gradient System ◽  
Gradient Coils ◽  
Temperature Controller ◽  
Mr Tomography

scholarly journals Design and development of polymerase chain reaction thermal cycler using proportional-integral temperature controller

2018 ◽  
Vol 14 (2) ◽  
pp. 213-218
Author(s):  
Chong Kim Soon ◽  
Nawoor Anusha Devi ◽  
Kok Beng Gan ◽  
Sue-Mian Then
Keyword(s):  
Polymerase Chain Reaction ◽  
Low Cost ◽  
Maximum Temperature ◽  
Gradient System ◽  
Chain Reaction ◽  
Temperature Controller ◽  
Proportional Integral ◽  
Integral Temperature ◽  
Polymerase Chain ◽  
Thermal Cycler

A thermal cycler is used to amplify segments of DNA using the polymerase chain reaction (PCR). It is an instrument that requires precise temperature control and rapid temperature changes for certain experimental protocols. However, the commercial thermal cyclers are still bulky, expensive and limited for laboratory use only.  As such it is difficult for on-site molecular screening and diagnostics. In this work, a portable and low cost thermal cycler was designed and developed. The thermal cycler block was designed to fit six microcentrifuge tubes. A Proportional-Integral temperature controller was used to control the thermal cycler block temperature. The results showed that the maximum temperature ramp rate of the developed thermal cycler was 5.5 °C/s. The proportional gain (Kp) and integral gain (Ki) of the PI controller were 15 A/V and 1.8 A/Vs respectively. Finally, the developed thermal cycler successfully amplified six DNA samples at the expected molecular weight of 150 base pair. It has been validated using the Eppendorf Mastercycler nexus gradient system and gel electrophoresis analysis

Magnetic Field Approximation in MR Tomography

PIERS Online ◽  
2007 ◽  
Vol 3 (8) ◽  
pp. 1250-1253
Author(s):  
Michal Hadinec ◽  
Pavel Fiala ◽  
Eva Kroutilova ◽  
M. Steinbauer ◽  
Karel Bartusek
Keyword(s):  
Magnetic Field ◽  
Field Approximation ◽  
Mr Tomography

A new Target Field Method for Optimizing Longitudinal Gradient Coils' Property

PIERS Online ◽  
2007 ◽  
Vol 3 (6) ◽  
pp. 865-869 ◽  
Author(s):  
Feng Qi ◽  
Xin Tang ◽  
Zhe Jin ◽  
Le Wang ◽  
Donglin Zu ◽  
...  
Keyword(s):  
Field Method ◽  
Gradient Coils ◽  
Longitudinal Gradient ◽  
Target Field

scholarly journals Relating a Rate-Independent System and a Gradient System for the Case of One-Homogeneous Potentials

2021 ◽  
Author(s):  
Alexander Mielke
Keyword(s):  
Gradient Flow ◽  
Careful Analysis ◽  
Flow Equation ◽  
Uniqueness Result ◽  
Gradient System ◽  
Independent System ◽  
Exact Relation ◽  
Flow Equations ◽  
Total Variation Flow ◽  
Energetic Solutions

AbstractWe consider a non-negative and one-homogeneous energy functional $${{\mathcal {J}}}$$ J on a Hilbert space. The paper provides an exact relation between the solutions of the associated gradient-flow equations and the energetic solutions generated via the rate-independent system given in terms of the time-dependent functional $${{\mathcal {E}}}(t,u)= t {{\mathcal {J}}}(u)$$ E ( t , u ) = t J ( u ) and the norm as a dissipation distance. The relation between the two flows is given via a solution-dependent reparametrization of time that can be guessed from the homogeneities of energy and dissipations in the two equations. We provide several examples including the total-variation flow and show that equivalence of the two systems through a solution dependent reparametrization of the time. Making the relation mathematically rigorous includes a careful analysis of the jumps in energetic solutions which correspond to constant-speed intervals for the solutions of the gradient-flow equation. As a major result we obtain a non-trivial existence and uniqueness result for the energetic rate-independent system.

scholarly journals Genetic recombination as a generalised gradient flow

2021 ◽  
Author(s):  
Frederic Alberti
Keyword(s):  
Arbitrary Number ◽  
Genetic Recombination ◽  
Reaction Network ◽  
Gradient Flow ◽  
Mass Action ◽  
Gradient System ◽  
Gradient Structure ◽  
Law Of Mass Action ◽  
Reversible Chemical Reaction ◽  
Time Partitioning

AbstractIt is well known that the classical recombination equation for two parent individuals is equivalent to the law of mass action of a strongly reversible chemical reaction network, and can thus be reformulated as a generalised gradient system. Here, this is generalised to the case of an arbitrary number of parents. Furthermore, the gradient structure of the backward-time partitioning process is investigated.

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