Tracking the individual magnetic wires' switchings in ferromagnetic nanowire arrays using the first-order reversal curves (FORC) diagram method

2015 ◽  
Vol 457 ◽  
pp. 280-286 ◽  
Author(s):  
Costin-Ionuţ Dobrotă ◽  
Alexandru Stancu
2008 ◽  
Vol 8 (11) ◽  
pp. 5725-5732 ◽  
Author(s):  
M. Ciureanu ◽  
F. Béron ◽  
P. Ciureanu ◽  
R. W. Cochrane ◽  
D. Ménard ◽  
...  

Nanowire arrays of Co and Ni have been obtained by current pulse electrodeposition into nanoporous alumina templates. By adjusting the pH of the bath, the microstructure of the Co wires was tailored, resulting in two types of arrays of crystalline Co—hcp, with c-axis nominally parallel (Co (c∥)), or nominally perpendicular (Co (c⊥)) to the wire. First-order reversal curve (FORC) diagrams provide information on average coercivity of the individual nanowire and the factors influencing the field created in the saturated array by the magnetostatic interactions. The dependences of this field on array geometry (wire length and diameter) and saturation magnetization were found to be in excellent agreement with theoretical predictions from a micromagnetic model. For arrays with lower wire diameter, the average coercivity of the individual wires is systematically higher than the coercivity of the array. The most important difference between the two Co series is in the dependence of the FORC diagrams on the wire diameter, with the Co (c⊥) showing significant pattern changes at large diameters. Two possible sources of those changes are discussed.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad Reza Zamani Kouhpanji ◽  
Ali Ghoreyshi ◽  
P. B. Visscher ◽  
Bethanie J. H. Stadler

Abstract Magnetic nanoparticles have been proposed as contact-free minimal-background nanobarcodes, and yet it has been difficult to rapidly and reliably decode them in an assembly. Here, high aspect ratio nanoparticles, or magnetic nanowires (MNWs), are characterized using first-order reversal curves (FORC) to investigate quantitative decoding. We have synthesized four types of nanowires (differing in diameter) that might be used for barcoding, and identified four possible “signature” functions that might be used to quickly distinguish them. To test this, we have measured the signatures of several combination samples containing two or four different MNW types, and fit them to linear combinations of the individual type signatures to determine the volume ratios of the types. We find that the signature which determines the ratios most accurately involves only the slope of each FORC at its reversal field, which requires only 2–4 data points per FORC curve, reducing the measurement time by a factor of 10 to 50 compared to measuring the full FORC.


2013 ◽  
Vol 429 ◽  
pp. 46-51 ◽  
Author(s):  
M. Almasi-Kashi ◽  
A. Ramazani ◽  
E. Golafshan ◽  
M. Arefpour ◽  
E. Jafari-Khamse

1994 ◽  
Vol 29 (1) ◽  
pp. 43-55 ◽  
Author(s):  
M Raoof ◽  
I Kraincanic

Using theoretical parametric studies covering a wide range of cable (and wire) diameters and lay angles, the range of validity of various approaches used for analysing helical cables are critically examined. Numerical results strongly suggest that for multi-layered steel strands with small wire/cable diameter ratios, the bending and torsional stiffnesses of the individual wires may safely be ignored when calculating the 2 × 2 matrix for strand axial/torsional stiffnesses. However, such bending and torsional wire stiffnesses are shown to be first order parameters in analysing the overall axial and torsional stiffnesses of, say, seven wire stands, especially under free-fixed end conditions with respect to torsional movements. Interwire contact deformations are shown to be of great importance in evaluating the axial and torsional stiffnesses of large diameter multi-layered steel strands. Their importance diminishes as the number of wires associated with smaller diameter cables decreases. Using a modified version of a previously reported theoretical model for analysing multilayered instrumentation cables, the importance of allowing for the influence of contact deformations in compliant layers on cable overall characteristics such as axial or torsional stiffnesses is demonstrated by theoretical numerical results. In particular, non-Hertzian contact formulations are used to obtain the interlayer compliances in instrumentation cables in preference to a previously reported model employing Hertzian theory with its associated limitations.


1966 ◽  
Vol 19 (2) ◽  
pp. 627-634 ◽  
Author(s):  
Mari J. K. Brown

Free recall of lists at different orders of approximation to English was compared to the recall of the same lists when the order of the words had been scrambled to destroy their sequential organization. Recall of the organized lists showed the typical improvement with increasing order of approximation. Recall of the scrambled lists was unrelated to the original order of approximation. The results indicate that increased recall with increasing order of approximation to English is not produced by systematic differences in the characteristics of the individual words comprising the approximations. When recall of the organized lists was scored in terms of the number of longer sequences present in recall, the number of recalled sequences of any given length increased as order of approximation to English increased, with the first order list showing proportionally less organization in recall than the second and higher order lists.


2019 ◽  
Vol 104 (6) ◽  
pp. e4.2-e4
Author(s):  
G Salis ◽  
N Medlicott ◽  
D Reith

BackgroundGentamicin is commonly used in the NICU setting and is often administered via long lines, which increases variability in the rate of administration. We aimed to model drug delivery pharmacokinetic parameters for intravenous gentamicin administered via umbilical venous catheters (UVCs).MethodsData was modelled from infusion simulations of gentamicin delivery using UVCs with a background flow rate of 0.5 ml/h.1 Different combinations of dose (2 mg, 5 mg) were given by bolus injection over 3–5 minutes, followed by a normal saline flush (1 ml, 2 ml). Gentamicin levels were measured at 5 minute intervals over an hour via high pressure liquid chromatography.Phoenix Certara (version 8.1) was used for modelling. An extravascular model with clearance removed was used to predict parameters: absorption constant (Ka), time lag (Tlag), and bioavailability (F). F was used to enable an estimate of the variability in dose administered. Different error models were tested to ascertain which best described the data.ResultsAn extravascular one compartment model with first order absorption and additive error best described the data. Estimates for the model with a 2 mg dose and 1 ml flush were Ka 0.34L/min, Tlag 1.28min, F 0.97, standard deviation (stdev) 0.14. For 2 mg, 2 ml flush, estimates were Ka 0.86L/min, Tlag 3.01min, F 0.87, stdev 0.01. For 5 mg, 1 ml flush, estimates were Ka 0.48L/min, Tlag 3.13min, F 1.03, stdev 0.12. For 5 mg, 2 ml flush, estimates were Ka 0.83L/min, Tlag 3.29min, F 1.09, stdev 0.02. For each model epsshrinkage and nshrinkage for Tlag and F were low, however nshrinkage for ka was 0.9999.ConclusionThis is the first known modelling of gentamicin delivery kinetics. The studies all had high nshrinkage for Ka, therefore the individual estimates of ka may be unreliable. Further studies with a higher number of replicates would provide more favourable data for estimating Ka.ReferenceLala AC ( 2016). Variability in neonatal gentamicin administration influencing drug delivery kinetics (Thesis, Master of Medical Science). University of Otago.Disclosure(s)No conflict of interest declared. Funding for research via the Freemasons Society of New Zealand.


Author(s):  
David Navas ◽  
Celia Sousa ◽  
Sergey Bunyaev ◽  
Gleb Kakazei

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