• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.70-75
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• 2013

The electrical separation joint as a filter circuit distributes the track circuit frequency. The electrical separation joint is classified into the interval where reinforcing bars are insulated and not insulated through the length of track circuit. In case of incorrectly setting up the length of electrical separation joint, the amplitude of current on the track circuit is not over standard current which is the standard of current on the track circuit and it effects on the close frequency on track circuit. Then, it makes an accident or makes a train not receive information for train control. In this paper, the electrical separation joint model is suggested and parameters are numerically calculated in the model. Moreover, the length of electrical separation joint is analyzed and is demonstrated by uisng Matlab and PSpice program.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1866-1870
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• 2019

Residual salt separation is an essential step in pyroprocessing because its reaction products, as prepared by electrochemical unit processes, contain frozen residual electrolyte species, which are generally composed of alkali-metal chloride salts (e.g., LiCl, KCl). In this study, a simple technique that utilizes high-temperature gas flux as a driving force to melt and push out the residual salt in the reaction products was developed. This technique is simple as it only requires the use of a heating gun in combination with a gas injection system. Consequently, $LiNO_3-ZrO_2$ and $LiCl-ZrO_2$ mixtures were successfully separated by the high-temperature gas injection (separation efficiency > 93%), thereby demonstrating the viability of this simple technique for residual salt separation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.67-79
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• 1996

This paper presents a composite luminance signal processing system for NTSC, PAL and SECAM standards. Eaxh of the three standards employs its own specifications of subcarmier bandwidth and luminance signal waveform. The proposed system, compatible to the specifications of the three standard and B/W TV, implements variable freqneucy characteristics by controlling filter coefficients. The major features of the system are a luminance/chroma separation unit and an aperture compensation unit. The luminance/chroma separation unit employes a notch filter selection a trap freqneyc to atenuate unwanted color signals in luminance signal bands. The aperture compensation unit comprises two subunits, to provide clear color definition for each of the three standards: a primary compensation circuit and a variable compensation circuits. The proposed system yields a 40 dB gain from the chroma/luminance separation and a 10 dB gain from the aperture compensation unit.

• Journal of Aerospace System Engineering
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• v.7 no.3
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• pp.20-25
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• 2013

In case of cube satellite, it is difficult to realize the same performance as commercial satellite due to its highly restricted unit accommodation space. To maximize the performance of the cube satellite, design concept considering the multi-function of satellite is required. In this paper, mechanism design of cube satellite which is applicable for the holding and release of multi-deployable structures has been proposed and investigated. In addition, a switch mechanism design for the autonomous system operation just after the cube satellite separation from P-POD has also been proposed. The effectiveness of the mechanism design for holding and release of multi-deployable structures has been demonstrated by EM test of the holding and release mechanism.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.2
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• pp.119-126
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• 1995

The purpose of this study is to develop the technique of energy recovery and energy saving by using the optimization of heat exchanger network synthesis. This article proposes a new method of determining the optimal target of a heat exchanger network synthesis problem of which data feature multiple pinch points. The system separation method we suggest here is to subdivide the original system into independent subsystems with one pinch point. The optimal cost target was evaluated and the original pinch rules at each subsystem were employed. The software developed in this study was applied to the Alko prosess, which is an alcohol production process, for the synthesis of heat exchanger network. It was possible to save about 15% of the total annual cost.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.145-152
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• 1998

This paper presents an optimum design of a rotor-bearing spindle system for a ultra centrifuge (80,000 RPM) supported by ball bearings with nonlinear stiffness characteristics. To obtain the nonlinear bearing stiffnesses, a ball bearing is modeled in five degrees of freedom and is analyzed quasi-statically. The dynamic behaviors of the nonlinear rotor-bearing system are analyzed by using a transfer-matrix method iteratively. For optimization. we use the cost function that simultaneously minimizes the weight of a rotor and maximizes the separation margins to yield the critical speeds as far from the operating speed as possible. Augmented Lagrange Multiplier (ALM) method is employed for the nonlinear optimization problem. The result shows that the rotor-bearing spindle system is optimized to obtain 9.5％ weight reduction and 21％ separation margin.

• Journal of Power System Engineering
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• v.3 no.1
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• pp.29-37
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• 1999

The flow characteristics of a NACA0012 airfoil was investigated in rectangular water circulating channel. The flow patterns around an airfoil at various angles of attack between $0^{\circ}\;and\;30^{\circ}\;at\;Re=1.91{\times}104$ were visualized and measured with 2-D PIV system and laser sheet illumination. Flow behaviors such as velocity distribution, kinetic energy and flow separation etc. around an airfoil were obtained by means of 2-D PIV system. The behaviors show the difference of flow pattern clearly and separation phenomena become more active with increasing angle of attack.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.3-8
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• 1999

In this paper, we propose a new active noise control system that cancels the only noise signal from the mixture selectively. A blind source separation realized by a dynamic recurrent neural network is used as a preprocessor of the active noise control system and separates the desired signal and the noise signal. The active noise control system adaptively generates an anti-noise signal to remove the only noise signal separated by the blind source separation. Computer simulation results show that the proposed scheme is effective to construct a selective attention system.

• Animal Bioscience
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• v.36 no.5
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• pp.810-817
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• 2023

Objective: The aim was to compare the behavioral response to full separation of cows and calves maintained together for 100 days or 24 h. Methods: Twelve Holstein-Friesian cow-calf pairs were enrolled into either treatment or industry groups (n = 6 cow-calf pairs/group). The treatment cows and calves were maintained on pasture together for 106±8.6 d and temporarily separated twice a day for milking. The Industry cows and their calves, were separated within 24 h postpartum. Triaxial accelerometer neck-mounted sensors were fitted to cows 3 weeks before separation to measure hourly rumination and activity. Before separation, cow and calf behavior was observed by scan sampling for 15 min. During the separation process, frequency of vocalizations and turn arounds were recorded. At separation, cows were moved to an observation pen where behavior was recorded for 3 d. A CCTV camera was used to record video footage of cows within the observation pens and behavior was documented from the videos in 15 min intervals across the 3 d. Results: Before separation, industry calves were more likely to be near their mother than Treatment calves. During the separation process, vocalization and turn around behavior was similar between groups. After full separation, treatment cows vocalized three times more than industry cows. However, the frequency of time spent close to barrier, standing, lying, walking, and eating were similar between industry and treatment cows. Treatment cows had greater rumination duration, and were more active, than industry cows. Conclusion: These findings suggest a similar behavioral response to full calf separation and greater occurrence of vocalizations, from cows maintained in a long-term, pasture-based, cow-calf rearing system when ompared to cows separated within 24 h. However, further work is required to assess the impact of full separation on calf behavior.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.257-265
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• 1995

Free amino acids were isolated from milk and their absolute amounts were determined by reversed phase high performance liquid chromatography after derivatization with dansyl chloride. The determination of D- and L-amino acids was based on achiral separation on a C18 column. It was found that milk contained totally 41.00 mg DL-amino acids in 100 mL milk. The level of D-amino acids to L-amino acids was determined by a column-switching system combining an achiral reversed phase separation and chiral chelate additive. The chiral separation was carried out with addition of the chiral Cu(N-benzyl-L-proline)2 chelate to the mobile phase in reversed phase liquid chromatography. It was found that the determination of 16 different amino acids is feasible in the milk sample with a C18 column separation and 12 D-amino acids out of the 16 amino acids can be determined via the column-switching system with chiral separation. 2.05% of D-glutamic acid and 2.93% of D-alanine were found in milk.