• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.869-875
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• 2007

Magnetic properties of electrical steel are, in general. measured by using Epstein frame or single sheet tester (SST). These methods, however, require very strict regulation of a specimen in its size and shape. thus, can not be easily applied to various types of specimen. On the other hand, a ring-test method, which measures only the isotropic properties, can be easily applied to most cases because it requires a toroidal-type specimen of arbitrary size. This method, especially, is considered as an unique available method for a bulk-type specimen. In this paper, a ring-test method is developed, and applied to the measurement of magnetic properties of a bulk-type electrical steel with a toroidal-type specimen. In the measurement, the magnetic properties and iron losses are measured and compared with each other at the both sinusoidal magnetic flux density and sinusoidal magnetic field intensity conditions under 0.2Hz and 60Hz alternating magnetic fields excitation. Through experimental measurements, a sinusoidal magnetic flux density condition is proven appropriate for the measurement of magnetic properties, including iron loss characteristics, of electrical steels.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1484-1494
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• 2017

We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

• Korean Journal of Human Ecology
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• v.21 no.1
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• pp.141-149
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• 2012

This study investigates the effects of wear training on blood pressure and blood lipid profiles. For the purpose of this research, 'wear training' refers to the alternating stimulation of temperature while using specific clothing under controlled situations ($18.8{\pm}0.2^{\circ}C$, $38{\pm}3%RH$). The participants alternated between two different garments producing a $1.5^{\circ}C$ difference in the innerest microclimate temperature over a period of 4 weeks. The experiments in this study were conducted in a comfortable environment after sufficient rest. The results were as follows. The systolic blood pressure and mean arterial pressure were lower in the post test than in the pre test (p<.05). The atherogenic index (AI) was also reduced and the LDL-C/HDL-C ratio increased (p<.05) in the post test. These results demonstrated that wear training positively affected improvement in vascular stiffness.

• Structural Engineering and Mechanics
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• v.25 no.1
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• pp.107-126
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• 2007

The problem related to the computation of bounds on plastic deformations for structures in plastic shakedown condition (alternating plasticity) is studied. In particular, reference is made to structures discretized by finite elements constituted by elastic perfectly plastic material and subjected to a special combination of fixed and cyclic loads. The load history is known during the steady-state phase, but it is unknown during the previous transient phase; so, as a consequence, it is not possible to know the complete elastic plastic structural response. The interest is therefore focused on the computation of bounds on suitable measures of the plastic strain which characterizes just the first transient phase of the structural response, whatever the real load history is applied. A suitable structural model is introduced, useful to describe the elastic plastic behaviour of the structure in the relevant shakedown conditions. A special bounding theorem based on a perturbation method is proposed and proved. Such theorem allows us to compute bounds on any chosen measure of the relevant plastic deformation occurring at the end of the transient phase for the structure in plastic shakedown; it represents a generalization of analogous bounding theorems related to the elastic shakedown. Some numerical applications devoted to a plane steel structure are effected and discussed.

• Environmental Engineering Research
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• v.22 no.4
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• pp.377-383
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• 2017

A tube-type ceramic membrane for microfiltration was developed, and the membrane module comprised of three membranes was also applied to biological carbon and nitrogen removal processes for post-treatment. Manufacturing the microfiltration membrane was successful with the structure and boundary of the coated and support layers within the membrane module clearly observable. Total kjeldahl nitrogen removal from effluent was additionally achieved through the elimination of solids containing organic nitrogen by use of the ceramic membrane module. Removal of suspended solids and colloidal substances were noticeably improved after membrane filtration, and the filtration function of the ceramic membrane could also easily be recovered by physical cleaning. By using the ceramic membrane module, the system showed average removals of organics, nitrogen, and solids up to 98%, 80% and 99.9%, respectively. Thus, this microfiltration system appears to be an alternative and flexible option for existing biological nutrient removal processes suffering from poor settling performance due to the use of a clarifier.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.111-116
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• 2011

Three-dimensional finite element analyses have been performed to improve the durability of bulkhead. To keep pace with design changes and concentrate on regions of interest, SUBMODEL technique in ABAQUS was used for analysis. An analysis was conducted with following load cases: 1) Cap press-fit, 2) Bearing crush, 3) Bolt assembly, 4) Hot assembly, 5) Firing load, 6) Alternating firing load, 7) 2nd hot assembly. Fatigue analysis was done using commercial software FEMFAT and fatigue factors at the interested regions such as bolt tip area, counter bore, breathing hole, honing clearance were calculated and compared to aid design validation. Finite element modeling in the area of thread engagement used a simple constraint equations. Increasing bolt length, to a minimum of 39 mm above joint face gives a better fatigue resistance to the bulkhead. Breathing hole helps not only circulate the air in the crankcase but also fatigue resistance of bulkhead by relieving the stress at the critical locations.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.653-662
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• 2000

A single experimental design (alternating treatment design) was used to compare the effects of the mobilization and heat therapy on the pain and mouth opening in patient with temporo-mandibular disorder (TMD). In the mobilization sessions, the physiotherapist performed two methods of the mobilization on the temporo-mandibular joints. In the heat therapy sessions, the patient received infrared and ultrasono on the temporo-mandibular joint. The mobilization and heat therapy were performed on alternate days during 10 days. Pain was measured by visual analogue scale (VAS) and mouth opening was measured by caliper. The results showed that mobilization and heat therapy were effective in pain reduce and mouth opening increase, and mobilization was superior to heat therapy in mouth opening increase and pain reduce.

• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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• pp.43-48
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• 2002

We carried out this subject to observe photoisomerization using 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group which has reversible to cis-trans by light irradiation. Spreading solutions for the LB films were prepared in chloroform($5.0{\times}10^{-5}$mol/L).We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of 8A5H and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in several solvents and mixture LB films.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.149-153
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• 1970

The present study deals with dynamical relationships between variations of common mackerel and horse mackerel catches in the waters adjacent to Korea for the years 1926 to 1969. The materials used here were obtained from Fishery Statistics published by the Bureau of Fisheries and the Fisheries Research and Development Agency of Korea, Secular variations of common mackerel and horse mackerel catches were classified intc five stages from A to E as shown in Fig. 2. As to variations of catch, the two species have alternating cycle trends occurring every ten years. With regard to the long period trend of catch, there is no correlation between annual variations of the species caught. Dynamical relationships between the two species showed a somewhat different pattern of catch as they transferred from one stage to another of the secular variations.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.3
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• pp.105-113
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• 2007

This study was conducted to analyze the effects of environmental factors such as soil moisture, light intensity, temperature and humidity on changes in cambial electrical resistance. To improve data quality, cambial electrical resistance was continuously measured at fixed points by using a data logger isolated from alternating current. The relationship between environmental factors and changes in cambial electrical resistance was also analyzed. The results are as follows: 1. Cambial electrical resistance is highly correlated to the temperature of the measured area(r=-0.934). Therefore, temperature compensation is needed to analyze the effects of other environmental factors on cambial electrical resistance changes. 2. If temperature is compensated for, the change of cambial electrical resistance is highly correlated to water vapor pressure(r=-0.836). 3. If temperature and humidity are compensated for, the change of cambial electrical resistance is highly correlated to intensity of light(r=-0.738). 4. Diurnal deviation of soil water potential is not more significantly related than the change of cambial electrical resistance. However, in the long-term, soil water potential and cambial electrical resistance are highly correlated(r=-0.831). This indicates that soil moisture significantly influences the long-term change of cambial electrical resistance.