Thermodynamics of Ising Rare-Earth Magnet in the Static Fluctuation Approximation

2014 ◽  
Vol 116 (6) ◽  
pp. 919-924
Author(s):  
A. A. Khamzin ◽  
R. R. Nigmatullin
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yucan Zheng ◽  
Zhihua Zhang ◽  
Kunlong Yan ◽  
Hongmei Guo ◽  
Mei Li ◽  
...  

Abstract Background The aim of this study was to characterize patients who ingested multiple rare-earth magnets, reveal the harm of rare-earth magnet foreign bodies in the digestive tract, and develop a clinical management algorithm. Methods This was a retrospective review of patients with rare-earth magnet foreign bodies in the digestive tract admitted to a university-affiliated pediatric medical center in China, between January 2016 and December 2019; the subset of medical data evaluated included clinical symptoms, signs, treatments and outcomes. Results A total of 51 cases were included in this study, including 36(70.6%) males and 15(29.4%) females. The magnets were passed naturally in 24(47.1%) patients and removed by intervention in 27(52.9%) patients, including 5(9.8%) cases by endoscopy and 22(43.1%) cases by surgery. Twenty-two (43.1%)cases had gastrointestinal obstruction, perforation, and fistula. Compared with the non-surgical group, the time of the surgical group from ingestion to arriving at the hospital was longer([80(5–336) vs 26(2–216)]hours, p < 0.001) while there was no significant difference in the mean age or the number of magnets swallowed. Conclusions Magnets are attractive to children, but lead to catastrophic consequences including gastrointestinal obstruction, perforation, and surgical interventions when ingested multiple magnets. Endoscopic resection should be urgently performed in the presence of multiple magnets as early as possible within 24 h, even in asymptomatic patients.


2004 ◽  
Vol 51 (3) ◽  
pp. 160-164
Author(s):  
Ken-ichi Machida ◽  
Masahiro Itoh ◽  
Masahiro Masuda ◽  
Seiji Kojima

2008 ◽  
Vol 22 (03) ◽  
pp. 257-266 ◽  
Author(s):  
A. S. SANDOUQA ◽  
B. R. JOUDEH ◽  
M. K. AL-SUGHEIR ◽  
H. B. GHASSIB

Spin-polarized atomic deuterium (↓D) is investigated in the static fluctuation approximation with a Morse-type potential. The thermodynamic properties of the system are computed as functions of temperature. In addition, the ground-state energy per atom is calculated for the three species of ↓D : ↓D 1, ↓D 2, and ↓D 3. This is then compared to the corresponding ground-state energy per atom for the ideal gas, and to that obtained by the perturbation theory of the hard sphere model. It is deduced that ↓D is nearly ideal.


2019 ◽  
Vol 61 (2) ◽  
pp. 395
Author(s):  
А.В. Силантьев

Abstract —Anticommutator Green’s functions and energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been obtained in an analytical form within the Hubbard model and static fluctuation approximation. The energy states have been classified using the methods of group theory, and the allowed transitions in the energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been determined. It is also shown how the energy levels of fullerene C_20 with the I _ h symmetry group are split with the symmetry reduction.


2020 ◽  
Vol 7 ◽  

A three-dimensional field solution is presented foraxially polarized permanent magnet cylinders. The fieldcomponents are expressed in terms of finite sums of elementaryfunctions and are easily programmable. They can be used todetermine the operating point of rare-earth magnet cylinders.They are also useful for performing rapid parametriccalculations of field strength as a function of materialproperties and dimensions. The field components aredeveloped for different magnet arrangements by taking intoaccount the back iron. Also the method of images is used. Usingthe field equations, three-dimensional analytical expressionsare derived for computing the magnetic force between axiallypolarized permanent-magnet cylinders for different magneticarrangements. The field calculated results are in goodagreement with the experimental data.


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