• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.11-15
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• 2018

In this study, a cancer treatment by accumulating and aggregating ferromagnetic particles in newborn blood vessels was examined. It is necessary for this treatment to control dispersion-aggregation property of ferromagnetic particles. Ferromagnetic particles required in this method disperse at low magnetic field, aggregate at high magnetic field and maintain the aggregation even after removal of the magnetic field. In order to control the dispersion-aggregation property, the surface of magnetite particles was modified with higher fatty acids having different lengths. As a result, we succeeded to prepare propionic acid-modified magnetite particles that form irreversible aggregation by magnetic field. The model experiments simulating newborn blood vessels showed that these particles can block the flow by the magnetic field, and the blockage was maintained after removal of the magnetic field.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.44.2-44.2
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• 2019

Turbulent motions perturb magnetic field lines and produce magnetic fluctuations. The perturbations leave imprints of turbulence statistics on magnetic field. Observation of synchrotron radiation is one of the easiest ways to study turbulent magnetic field. First, we obtained the spatial spectrum of synchrotron polarization so that shows how the spectrum is affected by Faraday rotation and how to recover the statistics of underlying turbulence magnetic field. Since polarized synchrotron intensity arising from magnetized turbulence are anisotropic along the direction of mean magnetic field. Secondly, we studied quadrupole ratio to quantitatively describe the degree of anisotropy introduced by magnetic field at multi-wavelengths. This work demonstrated that the spectrum and quadrupole ratio of synchrotron polarization can be very informative tools to get detailed information about the statistical properties of MHD turbulence from radio observations of diffuse synchrotron polarization.

• Advances in materials Research
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• v.12 no.2
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• pp.101-118
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• 2023

The purpose of this paper is to study the effects of magnetic field and gravitational field on fiber-reinforced thermoelastic medium with memory-dependent derivative. Three-phase-lag model of thermoelasticity (3PHL) is used to study the plane waves in a fiber-reinforced magneto-thermoelastic material with memory-dependent derivative. A gravitating magneto-thermoelastic two-dimensional substrate is influenced by both thermal shock and mechanical loads at the free surface. Analytical expressions of the considered variables are obtained by using Laplace-Fourier transforms technique with the eigenvalue approach technique. A numerical example is considered to illustrate graphically the effects of the magnetic field, gravitational field and two types of mechanical loads(continuous load and impact load).

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.26.2-26.2
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• 2010

It has been a puzzle in solar physics how a low-lying magnetic structure such as a solar prominence surrounded by a strongly line-tied overlying field sometimes intrudes through the latter and goes into eruption. A numerical simulation study of the solar coronal plasma reveals that a ballooning instability can explain this type of eruptive process. We consider an idealized situation with two flux ropes merging. When magnetic field lines from different flux ropes reconnect, a new field line connecting farther footpoints is generated. Since the field line length abruptly increases, the field line expands outward. If the plasma beta is low, this expansion takes place more or less evenly over the whole field line. If, on the other hand, the plasma beta is high enough somewhere in this field line, the outward expansion is not even, but is localized as in a bulging balloon. This ballooning section of the magnetic field penetrates out of the overlying field, and eventually the originally underlying field and the overlying field come to interchange their apex positions. This process may explain how a field structure that has stably been confined by an overlying field can occasionally show a localized eruptive behavior.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.278-283
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• 1996

We constructed a single path cylindrical mirror analyser(CMA) using field terminator methods. With computer simulation, the best fit voltage ratio and position of the field terminaor was determined with maintain log-scale equipotential line near both end of the CMA. Then we construct field terminator with voltage divider of metal-oxide resisters which reduces the fringe field effect. The resolving power of the CMA was better than $\Delta$E/E=0.4%.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.2
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• pp.47-53
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• 2018

In this paper, we investigate a collision avoidance algorithm for unmanned aerial vehicles using potential field based on the relative velocity of obstacles. The potential field consists of the attraction force and the repulsive force that are generated for the target and the obstacles. And the field can be classified into the attractive potential field generated by the target and the repulsive potential field generated by the obstacle, respectively. In this study, we construct an attractive potential field as a function of the distance between the UAV and the target position. On the other hand, a repulsive potential field is created by a function of distance and the relative velocity of the obstacle with respect to the UAV. The proposed potential field based collision avoidance algorithm is evaluate through simulations.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.78-85
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• 1995

Ornithine decarboxylase(ODC) is an indicate enzyme in carcinogenesis. We divided Sprague Dawley rats into six groups: control, electric field exposure, X-ray only irradiation, X-ray irradiation with electric field exposure group, Sr-90 injected group and Sr-90 and electric field complex exposure group. The ODC activity was measured in rat's bone marrow cell every week. The results were summarized as follows: The ODC activitied was increased in X-ray irradiated, Sr-90 injected and Sr-90 and electric field complex exposed group as compared with that of control(p<0.05). The ODC activity was increased comparing that of control neither in X-ray and electric field complex exposed group nor electric field only exposed group. This result suggests that the electric field doesn't have myeloid carcinogenicity and myeloid cancer incidence caused by ionized radiation is suppressed by electric field exposure.

• Hwankyungkyoyuk
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• v.14 no.1
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• pp.43-55
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• 2001

The purpose of this study was to review the current status and problems of the national qualification system in the Environmental field focusing on deficiencies of the regulatory system and qualities of environmental professional including the Environmental control Professional Engineer, Environmental Engineer, Environmental Industrial Engineer and Environmental field. An overview of the environmental field, its current status, domestic qualification items and training conditions in environment-related areas, laws of environmental field, and data of the job analysis were reviewed. The concrete and extensive development plans for the qualification system of the Environmental field are as follows: First of all, a job analysis should be made of on the introduction of new systems or policy modification to reflect technical changes and national policies about the environmental field in the qualification exam. Second, it is essential to prepare policies that are suitable for the qualification system in the Environmental field and that improve its effectiveness. Third, the appropriate policy measures should be taken in order to elevate the social standing of Environmental field qualification holders.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.616-621
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• 2002

With biological effects by ELF (Extremely Low Frequency) magnetic field generated from power system, the transient magnetic field from electric appliances is a major issue presently. Because the transient magnetic field induces higher current than the power frequency field inside living bodies, transient magnetic field exposure has been much focused. In this paper, it is shown that transient magnetic field from electric home appliances can be characterized as magnetic dipole moment. In this method, the dipole moment vector is assumed by allowing an uncertainty of 6dB in the estimated field. A parameter M that represents biological interaction was applied also. The proposed method was applied to 7 types of appliances (hair drier, heater, VDT, etc.) and their equivalent magnetic dipole moment and harmonic components were estimated. As the results, the useful data for quantifying magnetic field distribution around electric appliances were obtained.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.3
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• pp.23-30
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• 2014

Purpose : The purpose of this study was to grasp the general status and trend of the driving rehabilitation research focusing on interested topics, study subjects, therapeutic approaches, study designs, etc. Methods : It targeted 18 papers published in the RISS (Research Information Service System) from 2000 to 2014, and performed a descriptive statistical analysis by classifying these papers to topics, study subjects, study forms, study designs, study fields, and researchers. Results : As a result of the analysis, for the study form in the driving rehabilitation field, the rate of experimental papers was 61.1%, the highest. Major study subjects turned out to be occupational therapists, the disabled, and the aged, in order. For the study quality and design, the rate of survey and non randomized-single experimental study, which correspond to stage IV, was the highest, and the general study quality was found to be low. For the study field, the rates of the roles and recognition of occupational therapists, evaluation on driving ability of the disabled, and institutional improvement and future measures were the highest, each of which being 16.7%. Conclusion : Through this study, major study subjects and study quality in the driving rehabilitation field could be grasped, and it could be found that for development of the driving rehabilitation field, higher quality researches on more various study subjects would be needed in the future.