• Food Science of Animal Resources
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• v.33 no.6
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• pp.723-729
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• 2013

In this study, the quality characteristics due to the influence of various thawing methods on electro-magnetic and air blast frozen beef were examined. The loin and round of second grade Hanwoo were sliced into 5-7 cm thickness and packed with aerobic packaging. The packaged beef samples, which were frozen by air blast freezing at $-45^{\circ}C$ and electro-magnetic freezing at $-55^{\circ}C$, were thawed by 4 thawing methods with refrigeration ($4{\pm}1^{\circ}C$), room temperature (RT, $25^{\circ}C$), cold water ($15^{\circ}C$), and microwave (2450 MHz). These samples were thawed to the point, which were core temperature reached $0^{\circ}C$. Analyses were carried out to determine drip and cooking loss, water holding capacity (WHC), moisture contents and sensory evaluation. Frozen beef thawed by microwave indicated a lower drip loss (0.66-2.01%) than the other thawing methods (0.80-2.50%). Cooking loss after electro-magnetic freezing indicated 52.0% by microwave thawing for round compared with 41.8% by refrigeration, 50.1% by RT, and 50.8% by cold water. WHC thawing by microwave with electro-magnetic freezing didn't showed any difference depending on the thawing methods, while moisture contents was higher thawing by microwave with electro-magnetic freezing than refrigeration (71.9%), RT (75.0%), and cold water (74.9%) for round. The texture of sensory evaluation for round thawed by microwave result was the highest than refrigeration (4.7 point), RT (6.4 point) and cold water (6.6 point), while sensory evaluation was no significant difference. Therefore, it was shown that microwave thawing is an appropriate way to reduce the deterioration of meat quality due to freezing.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.763-771
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• 2013

This study was carried out to investigate the effects of various temperatures of electro-magnetic resonance and air blast freezing methods on the physicochemical quality of meat. Beef (loin and round), pork (belly and ham) and chicken (breast and leg) were purchased at a commercial market, and the meat was frozen using three methods: air blast freezing ($-20^{\circ}C$ and $-45^{\circ}C$) and electro-magnetic resonance quick freezing. Changes in the physicochemical properties of meat were analyzed by drip loss, cooking loss, water holding capacity (WHC) and proximate compositions. In comparison, regardless of the animal species and cuts of meat, electro-magnetic resonance quick freezing (2 h) resulted in a completely frozen product in a much shorter time than $-20^{\circ}C$ and $-45^{\circ}C$ air blast freezing (24 h and 8 h, respectively). Drip loss of loin which had underwent electro-magnetic resonance quick freezing were significantly (p<0.05) lower than those of the other two treatments, but cooking loss and water holding capacity were the highest at 43.7% and 60.7%, respectively (p<0.05). Characteristics such as crude protein, crude fat and moisture compositions showed significant differences, depending on the cuts and freezing methods (p<0.05). The fat composition of electro-magnetic resonance quick frozen loin and round were significantly low (p<0.05). However, moisture content was the highest compared to other freezing methods, as 67.1% and 71.9%, respectively (p<0.05). Electro-magnetic resonance quick freezing was an appropriate way to reduce the deterioration of meat quality due to freezing, and the drip loss was least for the part with low moisture, low protein, and high fat.

• Korean Journal of Materials Research
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• v.11 no.11
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• pp.972-977
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• 2001

It was investigated the effect of ultrasonic treatment on magnetic property of ultra fine magnetic Fe powders ($\alpha$-Fe) for magnetic tape. The properties were characterized with vibrating sample magnetometer (VSM), particle size analyzer (PSA) and scanning electron microscope (SEM). At 4hours ultrasonic treatment of 70 kHz, magnetic properties such as squareness ratio (S.Q. : 0.8868), orientation ratio (O.R. : 2.45) and switching field distribution (S.F. D. : 0.394) before taping were relatively enhanced. Cumulative particle size distribution of less than 5$\mu\textrm{m}$ fine powder was above 90% below 1 hour leaving time after ultrasonic treatment and it was supposed that ultrasonic treatment prevent aggregation. The magnetic values of S.Q. and S.F.D. of tape manufactured at 70 kHz and 4hour ultrasonic treatment were improved from 0.7747, 0.3818 to 0.8037, 0.3706, respectively. Electro-magnetic property used as in-output signal characteristic was improved, which showed that ultrasonic treatment developed the magnetic properties.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.69-70
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• 2005

In order to prevent the arc blow at the FCA welding system with multi-torches, the effects of arc length on the magnetic flux at the FCA weldment was evaluated using electro-magnetic filed analysis. Magnetic flux density around arc are slightly increased with an increase in the arc length. Based on the FEA results, the minimum distance of torches to control arc blow was established.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1039-1041
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• 2003

There are many advantages of the Magnetic Bearing system, compared with conventional contacting bearing systems. Since the spindle in the Magnetic Bearing system is levitated by electro-magnetic forces and rotates without mechanical friction, it can run without lubrication. So, it can run in the extreme circumstances, e.g. a vacuum condition in the space.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.38-51
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• 2007

This paper describes research results for the measurement and analysis method of magnetic signatures generated from the ship's magnetic mock-up model. In this paper, we present the theoretical and experimental techniques for the separation of the permanent and the induced magnetic field from the measured magnetic signature of the mock-up model. Also, we describe the prediction method of the induced magnetic field generated from mock-up model using the Magnet s/w, one of the FEM analysis tools for the electro-magnetic field and the magnetic dipole modelling method based on the least square techniques. The proposed modelling and analysis methods can be used for the prediction and the analysis of the static magnetic field generated from the real naval ship as well as the mock-up model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1047-1048
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• 2010

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.4-4
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• 2004

• Structural Engineering and Mechanics
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• v.27 no.5
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• pp.609-623
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• 2007

The problem of a semi-infinite magneto-electro-elastically impermeable mode-III crack in a magneto-electro-elastic material is considered under the action of impact loads. For the case when a pair of concentrated anti-plane shear impacts, electric displacement and magnetic induction impacts are exerted symmetrically on the upper and lower surfaces of the crack, the magneto-electro-elastic field ahead of the crack tip is determined in explicit form. The dynamic intensity factors and dynamic energy density factor are obtained. The method adopted is to reduce the mixed initial-boundary value problem, by using the Laplace and Fourier transforms, into three simultaneous dual integral equations, one of which is converted into an Abel's integral equation and the others into a singular integral equation with Cauchy kernel. Based on the obtained fundamental solutions of point impact loads, the solutions of two kinds of different loading cases are evaluated by integration. For some particular cases, the present results reduce to the previous results.

• Journal of Biosystems Engineering
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• v.17 no.3
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• pp.223-228
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• 1992

This study was conducted to develop an electro-hydraulic three-point hitch control system using an electro-hydraulic servo valve and microcomputer and to investigate the performance of the three-point hitch control system through indoor and field experiments. 1. The results from indoor experiments coincided with those from computer simulation reported in the previous paper. However, the draft control with the value 4 of Kd showed a slight sustained oscillation after it reached the draft set. 2. From the field experiments, it appeared that the RMS errors increased with the ground speed of tractor. In position control, the three-point hitch control system with electro-hydraulic servo valve showed better performance than that with on-off electro-magnetic valve in the ground speed less than 1.6 m/s. In draft control, however, there was no significant differece in performance between those two systems. 3. In depth control, the both types of electro-hydraulic three-point hitch control system showed better performance than the conventional mechanical-hydraulic three-point hitch control system.