scholarly journals The thermodynamics of magnetization.

1936 ◽  
Vol 155 (884) ◽  
pp. 70-101 ◽  
Author(s):  
Edward Armand Guggenheim ◽  
Charles Galton Darwin
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Induction ◽  
Magnetic Field Intensity ◽  
Magnetic Energy ◽  
Comprehensive Treatment ◽  
Accurate Analysis ◽  
General Validity ◽  
Magnetic Systems ◽  
The Magnetic Field

An accurate analysis of the thermodynamics of magnetic systems has to our knowledge never been made. The accounts given in the usual sources of reference are slight. Quite recently Stoner has tried to remedy this deficiency by a paper full of interest, but there are several points in his treatment which seem to us not altogether free from objection. We are therefore attempting in the present paper to give an accurate and fairly comprehensive treatment of the subject, in which the method of approach is somewhat different. This treatment seems to clarify the situation considerably. In particular we give a much more thorough analysis of pressure-volume effects than has previously been attempted. At the end of our paper we consider the relation between some of Stoner's formulae and our own. The thermodynamics of magnetic systems may be regarded as an extension of the electrodynamics of such systems to take account of thermal changes and volume changes of the magnetic matter. The chief difficulty encountered was that of finding a logically consistent treatment of magnetic energy from a purely electrodynamic aspect. In most of the recognized text-books either the treatment is not self-consistent or else it is assumed that the ratio of the magnetic induction to the magnetic field intensity is a constant. In a thermodynamic treatment this assumption may not be made even for diamagnetic and paramagnetic substances, because even supposing it to be valid at constant temperature it will not be valid when the temperature varies. Nor ca it generally be accurate both for variations at constant volume and for variations at constant pressure. It is therefore essential to start with a formula for magnetic energy which is independent of any assumed relation between the magnetic induction and the magnetic field intensity other than that each is a single valued continuous function of the other. This subject has been discussed in another paper where a formula of general validity for magnetic energy was obtained. We shall make this the basis of the present treatment.

Tunable amplified spontaneous emission based on liquid magnetically responsive photonic crystals

2019 ◽  
Vol 7 (13) ◽  
pp. 3740-3743 ◽  
Author(s):  
Ying Li ◽  
Yue Long ◽  
Guoqiang Yang ◽  
Chen-Ho Tung ◽  
Kai Song
Keyword(s):  
Magnetic Field ◽  
Photonic Crystals ◽  
Spontaneous Emission ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Amplified Spontaneous Emission ◽  
The Magnetic Field

The wavelength of amplified spontaneous emission based on liquid magnetically responsive photonic crystals can be tuned by simply changing the magnetic field intensity.

scholarly journals A Novel Method for Improving Low-Temperature Flotation Performance of Nonpolar Oil in the Molybdenite Flotation

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 609 ◽  
Author(s):  
Wan ◽  
Qu ◽  
Li ◽  
He ◽  
Bu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Low Temperature ◽  
Interfacial Tension ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Maximum Surface ◽  
Flotation Recovery ◽  
Flotation Performance ◽  
The Magnetic Field

Nonpolar hydrocarbon oil (NHO) is one of the most extensively used collectors in the flotation of molybdenite due to its excellent selectivity. However, NHO has low sensibility at pulp temperature. At low temperatures (<283 K), although more kerosene is used, the recovery of molybdenite flotation is still lower than at room temperature. In this study, magnetizing treatment, which is an efficient, low-cost, innovative, and environmentally friendly emulsification method, was used to improve the flotation performance of NHO in low-temperature molybdenite flotation. The test results showed that, compared with unmagnetized kerosene (UMK), the optimum dosage of magnetized kerosene (MK) could be reduced by 11% at 298 K. At the same dosage of kerosene, the flotation recovery of MK was 3% higher than UMK at 278 K. The surface tension measurement results showed that the surface tension of MK rose periodically as the magnetic field intensity increased, and there was a maximum surface tension within each period. Further, the magnetic field intensity had the maximum flotation recovery of molybdenite at the maximum surface tension of MK. Combined with the analysis based on the Girifalco–Good theory and the static drop volume method of interfacial tension, the interfacial tension of kerosene–water was shown to decrease with the increase of the surface tension of kerosene. This finding indicates that the dispersibility of kerosene in pulp could be improved by reducing the size of oil droplets, thereby improving the molybdenite flotation recovery of kerosene at low-temperature pulp. It is helpful to improve the flotation recovery of molybdenite using NHO as a collector for low-temperature pulp (<283 K).

scholarly journals Optical Birefringence Growth Driven by Magnetic Field in Liquids: The Case of Dibutyl Phosphate/Propylamine System

2019 ◽  
Vol 10 (1) ◽  
pp. 164 ◽  
Author(s):  
Mikolaj Pochylski ◽  
Domenico Lombardo ◽  
Pietro Calandra
Keyword(s):  
Magnetic Field ◽  
Self Assembly ◽  
Magnetic Field Intensity ◽  
Magnetic Energy ◽  
Molar Ratio ◽  
Molecular Liquids ◽  
Microscopic Scale ◽  
Intensity Response ◽  
Soft Particles ◽  
The Magnetic Field

Magnetically-induced birefringence is usually low in molecular liquids owing to the low magnetic energy of molecules with respect to the thermal one. Despite this, it has been found that a mixture of dibutyl phosphate and propylamine at propylamine molar ratio (X) around 0.33 surprisingly gives an intense effect (∆n/λ ≈ −0.1 at 1 Tesla). In this paper the time- and intensity- response to the magnetic field of such mixture have been studied. It was found that the reaction to the magnetic field is unusually slow (from several minutes to hours) depending of the magnetic field intensity. On the basis of the data, the model of orientable dipoles dispersed in a matrix enables to interpret the magnetic field-induced self-assembly in terms of soft molecules-based nanostructures. The analogy with systems made of magnetically polarizable (solid or soft) particles dispersed in liquid carrier allows understanding, at the microscopic scale, the molecular origin and the supra-molecular dynamics involved in the observed behavior. The data present a novel phenomenon in liquid phase where the progressive building up/change of ordered and strongly interacting amphiphiles is driven by the magnetic field.

Viscosity of Potassium Dihydrogen Phosphate Aqueous Solution within Magnetic Field

2017 ◽  
Vol 898 ◽  
pp. 1783-1786
Author(s):  
Lei Zhang ◽  
Yi Su ◽  
Yu Lin Wu ◽  
Yao Liu ◽  
Yong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Extreme Values ◽  
Potassium Dihydrogen Phosphate ◽  
Experimental Results ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
The Magnetic Field

The viscosity of potassium dihydrogen phosphate, KH2PO4 (KDP), aqueous solution within magnetic field was studied. Experimental results showed that, the viscosity of saturated KDP solution exhibited multiple extreme values when the magnetic field intensity increased from 0 Gs to 2250 Gs. Influences of the magnetic field intensity on the viscosity of KDP solution were very complicated. It’s concerned with the temperature and the concentration of solution. As the KDP was produced from aqueous solution within magnetic field, the temperature and the concentration of solution also needed to be carefully controlled. Magnetic field with intensity values of 300 Gs, 600 Gs and 1800 Gs, all have the strong effects on the structures of KDP aqueous solution.

The role of the magnetic field intensity and geometry in the type III burst generation

Solar Physics ◽  
1990 ◽  
Vol 130 (1-2) ◽  
pp. 31-37 ◽  
Author(s):  
P. Zlobec ◽  
V. Ruždjak ◽  
B. Vršnak ◽  
M. Karlický ◽  
M. Messerotti
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Type Iii ◽  
The Magnetic Field

Improved the Performance of Focusing Deep Hyperthermia Inductive Heating for Breast Cancer Treatment by Using Ferro-Fluid with Magnetic Shielding System

2013 ◽  
Vol 325-326 ◽  
pp. 353-358 ◽  
Author(s):  
Thosdeekoraphat Thanaset ◽  
Santalunai Samran ◽  
Thongsopa Chanchai
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Fluid ◽  
Magnetic Field Intensity ◽  
Magnetic Shielding ◽  
Inductive Heating ◽  
Surrounding Healthy Tissue ◽  
The Magnetic Field ◽  
Shielding System ◽  
Deep Hyperthermia

The performance improved of focusing deep hyperthermia inductive heating for breast cancer treatment using magnetic fluid nanoparticles with magnetic shielding system has been presented in the paper and the results are discussed. It is a technique challenge in hyperthermia therapy is to control locally heat the tumor region up to an appropriate temperature to destroy cancerous cells, without damaging the surrounding healthy tissue by using magnetic fluid nanoparticles and cylindrical metal shielding with aperture. We show that the magnetic field intensity can be controlled by changing the aperture size to suitable. In addition, the position of the heating can be controlled very well with the magnetic fluid together with shielding system. In the simulation, the inductive applicator is a ferrite core with diameter of 7 cm and excited by 4 MHz signal. Results have shown that the temperature increments depend on the magnetic fluid nanoparticles. In addition, the magnetic field intensity without damaging the surrounding healthy tissue when used magnetic shielded system. These results demonstrate that it is possible to achieve higher temperatures and to focus magnetic field intensity where the nanoparticles and magnetic shielding system are used.

Etude Numérique de la Section Efficace de Diffusion d'un Faisceau Laser par un Plasma en Champ Magnétique. Application à la Détermination Expérimentale de la Direction du Champ Magnétique de Confinement

1973 ◽  
Vol 51 (3) ◽  
pp. 266-276 ◽  
Author(s):  
R. L. Meyer ◽  
G. Leclert ◽  
M. Felden
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Scattered Wave ◽  
Magnetic Field Direction ◽  
Section Efficace ◽  
Experimental Conditions ◽  
Champ Magnétique ◽  
The Magnetic Field

We study the influence of the magnetic field intensity and direction with respect to the wave vector on the scattering cross-section resonances. We deduce the best experimental conditions for studying these resonances. It is shown that the spectrum modulation of the scattered wave can be used to measure, in some configurations, the confining magnetic field direction.

Design and Fabrication of a Micro-Actuator Based on Electromagnetic Membrane Device

2012 ◽  
Vol 488-489 ◽  
pp. 1451-1456
Author(s):  
Rong Hua Ma ◽  
Jian Hao Zhong
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Physical Size ◽  
Ac Power ◽  
Coil Structure ◽  
Electro Magnetic ◽  
Ndfeb Permanent Magnet ◽  
The Magnetic Field ◽  
A Current

The purpose of this study is to develop a micro electro-magnetic actuator manufactured by MEMS-based fabrication and electroplating techniques. This actuator presented a novel technique in the electromagnetic fabrication and smaller physical size than the traditional counterparts for micro actuators and provides a faster response time and lower cost. A micro coil structure is released from FeCl3 etchant and bonded on a thin film (Parafilm”M”, Pechiney Plastic Packaging Inc.) to achieve an actuator-membrane structure. When an external AC power is applied to a micro coil, a magnetic field is created to attract and repel through an NdFeB permanent magnet, and the displacement of the membrane is increased as a current of AC power. The results show the measured magnetic field intensity weakens as the distance between the coil and the Gauss meter probe increases. However, it is observed that the magnetic field intensity does not increase linearly with the number of series coils, which is due to the distance between series coils.

Comparison of the Effects of Bias Voltage and Transverse Magnetic Field on the Macro-Particles Distribution on the Surface of TiN Films Prepared by Arc Ion Plating

2011 ◽  
Vol 337 ◽  
pp. 300-306
Author(s):  
Wen Chang Lang
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Transverse Magnetic ◽  
Key Factor ◽  
Influence Parameter ◽  
Two Parameters ◽  
Influence Degree ◽  
The Magnetic Field

The object of this article is to make research on the influence of transverse magnetic field and pulse bias on macro-particles on the surface of film, find the systematic law and analyze the influence law and reasons of the two parameters (transverse magnetic field and pulse bias), according to the mechanism of arc spot movement and the interaction between macro-particles and plasma. Moreover, this article aims at seeking the most important influence parameter and comparing the effect of the two parameters. Research in this paper indicates that: the key factor is the magnetic field controlled arc spot movement, because the influence of magnetic field on reducing macro-particles is much larger than bias, and the influence degree of bias on macro-particles varies with the magnetic field intensity; action of bias is obvious under the condition of low magnetic field intensity, but as the magnetic field intensity increases, its action becomes weaker and weaker; besides, purification effect of bias on particles in larger size is better than on particles in smaller size.

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