• Journal of Power Electronics
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• v.17 no.2
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• pp.422-431
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• 2017

The equivalent circuit of a three-leg, four-wire voltage source converter (VSC) is derived using switching functions. Simulations and experiments are conducted (i) to investigate the effects of the zero sequence on VSCs when a three-phase imbalance exists and (ii) to use the consistency of simulations and laboratory experiments to validate the equivalent circuit. The impact of a three-phase imbalance on the VSC has yet to be fully investigated because of the lack of an equivalent circuit to show rigorously how the zero sequence currents flow through the VSC.

• Physical Therapy Korea
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• v.1 no.1
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• pp.83-87
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• 1994

The purpose of this paper is to provide an overview of the clinical physical therapy program used at the University of Yonsei Rehabilitation Hospital, for the practicing university trained physical therapists who may be unfamiliar with patients who have suffered a myocardial infarction. The four primary phases of the cardiac physical therapy graded exercise program are: 1) coronary care unit program (phase I), 2) general ward program (phase II), 3) convalescence program (phase III), 4) maintenance program (phase IV). The exercise prescription defines the exercise intensity, duration, frequency, and mode of exercise a after pre- discharge low level graded exercise test(LL-GXT) or symptom limited maximum graded exercise test. A typical exercise routine consists of preparation warm-up exercise, therapeutic exercise, cool-down exercise. Physical therapy is involved in the acute care and rehabilitation of the patient after a myocardial infarction. Therefore, the physical therapist must throughly comprehened the cardiac anatomy, cycle, performance, conduction system, pathogenesis, risk factors, and exercise benefits.

• 한국전산유체공학회:학술대회논문집
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• 1996.05a
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• pp.58-67
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• 1996

This paper describes some computational results of various energy and environmental systems using Patankar's SIMPLE method. The specific topics handled in this study are jet bubbling reactor for flue gas desulfurization, cyclone-type afterburner for incineration, 200m tall stack for 500 MW electric power generation, double skin and heat storage systems of building energy saving for the utilization of solar heating, finally turbulent combustion systems with liquid droplet or pulverized coal particle. A control-volume based finite-difference method with the power-law scheme is employed for discretization. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, that is, SIMPLEC. Reynolds stresses are closed using the standard $k-{\varepsilon}$ and RNG $k-{\varepsilon}$ models. Two-phase turbulent combustion of liquid drop or pulverized coal particle is modeled using locally-homogeneous, gas-phase, eddy breakup model. However simple approximate models are incorporated for the modeling of the second phase slip and retardation of ignition without consideration of any detailed particle behavior. Some important results are presented and discussed in a brief note. Especially, in order to make uniform exit flow for the jet bubbling reactor, a well-designed structure of distributor is needed. Further, the aspect ratio in the double skin system appears to be one of important factors to give rise to the visible change of the induced air flow rate. The computational tool employed in this study, in general, appears as a viable method for the design of various engineering system of interest.

• KSBB Journal
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• v.15 no.1
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• pp.55-59
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• 2000

Protease-catalyzed liberation of sialyloligosaccharide from raw egg yolk was investigated in biphasic system, water-immiscible hexane system. Biphasic system 1, in which water was the continuous phase, was better than the opposite biphasic system ll in sialyloligosaccharide liberation. The optimal conditions of temperature, water content and reaction time were $30^{\circ}C$, 20% and 12 hours, respectively. Protease activity was strongly influenced by the amount of water present in the reaction mixture. The liberation of sialyloligosaccharide was accelerated by protease pre-treatment at $30^{\circ}C$ in 0.2 M NaCl solution, prior to addition of hexane (Biphasic system I).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.34-42
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• 2016

In order to prepare for the type approval test for the United States Coast Guard (USCG) Phase-II of Ballast Water Treatment System (BWTS), a phytoplankton mass culture was conducted in a mesocosm enclosure. We evaluated the response of the phytoplankton community after nutrient addition (+N, +P, and +NP) and investigated the development of the species with increasing culture time. After nutrient dosing, the phytoplankton population significantly (p < 0.05) increased from day 1 to day 3, depending on the nutrient treatments In particular, the specific growth rate of the phytoplankton community in the case of +NP treatment and + N treatment were estimated to be $2.47d^{-1}$ and $1.98d^{-1}$, respectively. The phytoplankton population density in the case of + NP treatment was approximately 50 times higher than that of the control group, suggesting that these treatments could be useful for mass culturing phytoplankton (> 75% of natural community) for the approval regulation of USCG Phase-II. In the phytoplankton community of the mesocosm, Pseudo-nitzchia spp. dominated in the logarithmic growth phase. The cell density decreased significantly (p < 0.05) with increasing time, coinciding with the nutrient limitation. At that time, the dominance of Pseudo-nitzchia spp. shifted to that of Cylindrotheca closterium. Therefore, the optimum nutrient concentration ($N:30{\mu}M$, $P:3{\mu}M$) and reasonable harvesting time (after 3 days in summer) found in this study for the mass culturing of phytoplankton may be helpful to meet the USCG Phase-II biological criteria to be used in BWTS.

• 전기의세계
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• v.20 no.4
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• pp.5-11
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• 1971

This is a study on the insulation methods of home appliances and wiring devices proper to the new electric distribution system, primary side is 22.9/13.2KV, 3 phase 4 wire multigrounding system and secondary side is 380/220V, 3 phase 4 wire common neutral system. 1800V is determined as the electrical insulation voltage of the functional insulation because the abnormal voltage rise of the neutral line is 1300V. In the case of the functional insulation faults, the following safety methods will be suggested to protect the accidental faults: (a) class I appliance (accessible metal part is earthed), (b) class II appliance (doublly insulated), (c) class III appliance (operates at low voltage source). The mechanisms of the wiring devices are not improved to guarantee for the harmful electric shock but also the electrical insulation voltage is rised to 2000V.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1796-1802
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• 2017

Objective: This experiment was conducted to evaluate the optimal space allowance on growth performance, blood profile and pork quality of growing-finishing pigs. Methods: A total of ninety crossbred pigs [$(Yorkshire{\times}Landrace){\times}Duroc$, $30.25{\pm}1.13kg$] were allocated into three treatments (0.96: four pigs/pen, $0.96m^2/pig$; 0.80: five pigs/pen, $0.80m^2/pig$; 0.69: six pigs/pen, $0.69m^2/pig$) in a randomized complete block design. Pigs were housed in balanced sex and had free access to feed in all phases for 14 weeks (growing phase I, growing phase II, finishing phase I, and finishing phase II). Results: There was no statistical difference in growing phase, but a linear decrease was observed on average daily gain (ADG, p<0.01), average daily feed intake (ADFI, p<0.01), and body weight (BW, p<0.01) with decreasing space allowance in late finishing phase. On the other hand, a quadratic effect was observed on gain to feed ratio in early finishing phase (p<0.03). Consequently, overall ADG, ADFI, and final BW linearly declined in response to decreased space allowance (p<0.01). The pH of pork had no significant difference in 1 hour after slaughter, whereas there was a linear decrease in 24 h after slaughter with decreasing space allowance. Floor area allowance did not affect pork colors, but shear force linearly increased as floor space decreased (p<0.01). There was a linear increase in serum cortisol concentration on 14 week (p<0.05) with decreased space allocation. Serum IgG was linearly ameliorated as space allowance increased on 10 week (p<0.05) and 14 week (p<0.01). Conclusion: Data from current study indicated that stress derived from reduced space allowance deteriorates the immune system as well as growth performance of pigs, resulting in poor pork quality. Recommended adequate space allowance in a grow-to-finish production system is more than $0.80m^2/pig$ for maximizing growth performance and production efficiency.

• Proceedings of the KSRS Conference
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• v.1
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• pp.372-375
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• 2006

The MSC is a high resolution multi-spectral camera system which is mounted on the KOMPSAT-II satellite. The electro-optic camera system has a refocusing mechanism which can be used in-orbit by ground commands. By adjusting locations of some elements in optics, the system can be focused precisely. The focus mechanism in MSC is implemented with stepper motor and potentiometer. By reading the value of the potentiometer, rough position of the motor can be understood. The exact location of the motor can not be acquired because the information from the potentiometer can not be so accurate. However, before and after certain events of the satellite, like a satellite launch, the direction of the movement or order of the magnitude of the movement can be understood. In this paper, the trend analysis of the focus motor position during the ground test phase is introduced. This result can be used as basic information for the focus calibration after launch. By studying the long term trend, deviation from the best focal point can be understood. The positions of the focus motors after launch are also compared.

• The Journal of the Petrological Society of Korea
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• v.17 no.2
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• pp.83-94
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• 2008

The Pungcheon-myeon, Andong, consists mainly of Precambrian metamorphic rocks, Jurassic igneous rocks, Cretaceous sedimentary rocks (Hasandong, Jinju and Iljik Formations) and Cretaceous igneous rocks (gabbroic rocks, dykes), in which several major faults are developed; Andong fault of ENE trend, which is the boundary fault of the Cretaceous Gyeongsang Basin and the Precambrian-Jurassic basement (Yeongnam Massif), Namhu fault parallel to it, Maebong fault of NNW direction, bow-shaped Gwangdeok fault of ENE direction which is convex toward SSE direction, and Hahoe fault of NNE direction. This paper is researched the geological structures around these major faults by means of the detailed geometric analysis on beddings, joints, faults and drag folds. As a result, a reverse slip faulting of top-to-the SSE movement accompanied with a regional drag folding is recognized from the arrangement of bedding poles measured around the Gwangdeok and Hahoe faults at its northeastern extension, and a zone of Gwangdeok drag fold of 150-300 m width, which is wider at the central and eastern parts of Gwangdeok fault and narrower at its western part and Hahoe fault, is also defined. It indicates that the Hahoe and Gwangdeok faults are a single fault and their movements are coeval unlike the results of earlier reasearchers. And, In this area are recognized two types of faults [(E)NE${\sim}$EW(fault I), WNW${\sim}$NNW (fault II), trending faults] and four types of joints [EW (I), (N)NW (II), NNE (III), NE (IV) trending joints]. These fractures were formed at least through four different events, named as Dn to Dn+3 phases. (1) Dn phase; the formation of joint (I) (Gwangdeok joint) and the intrusion of acidic dykes of EW trend under the compression of EW direction. (2) Dn+1 phase; the formations of joint (II) (Maebong joint), lens-shaped boudinage of acidic dykes, oblique-slip reverse fault (Fault I-Gwangdeok fault) under the compression of (N)NW direction, and the formation of regional zone of Gwangdeok drag fold accompanying the Gwangdeok faulting. (3) Dn+2 phase; those of joint (III), Fault II (Maebong fault) by dextral strike-slip movement of Maebong joint under the compression of NNE direction, and the extension cutting of Dn+1 structures due to the Maebong faulting. (4) Dn+3 phase; the jointing (IV) and the reactivation of Fault II as oblique-slip type with predominant dextral motion which took place under the compression of NE direction. It also suggests that the Maebong fault is not a tear fault deveolped during thrust tectonics of the Andong and Gwangdeok faults but is a post-fault during different tectonic event.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.697-708
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• 1992

Liquid Chromatographic behavior of Ni(II) in Isonitrosoethylacetoacetate Imine(IEAA-NR), Ni(IEAA-NH)(IEAA-NR)(R = H, CH_3, C-2H_5, n-C_4H_9, C_6H_5-CH_2) chelates were investigated by reversed-phase HPLC on Micropak MCH-5 column using methanol/water as mobile phase. The optimum conditions for the separation of Ni(IEAA-NH)(IEAA-NR) chelates were examined with respect to the effect of the flow rate, sample solvent, mobile phase strength and column temperature. It was fo$und that metal chelates were properly eluted in an acceptable range of capacity factor value(0{\le}logk'{\le}1). The dependence of the logarithm of capacity factor (k') on the volume fraction of water in the binary mobile phase as well as on the liquid-liquid extraction distribution ratio (Dc) in methanol-water/n-alkane extraction system showed the good linearties, and the dependence of the logarithm of capacity factor (k') on the column temperature and on the enthalpy exhibited the good linearties, and the compensation temperature ({\beta}) from the slope was 773.47{\circ}K. It was suggested that the retention of metal chelates was largely affected by the hydrophobic effect.