• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.558-566
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• 2007

The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of refrigerant charge amount was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2400 mm length. The experimental results summarize as the followings : As the refrigerant charge ratio of $CO_2$ heat pump system increases, the discharge pressure and compressor ratio increases, but mass flow rate of refrigerant decreases. Also the compressor work increases with the increase of refrigerant charge ratio. However, the heating and cooling capacity of $CO_2$ heat pump decreases as the refrigerant charge ratio increases. The maximum heating COP of $CO_2$ heat pump system presented at 0.25 refrigerant charge ratio. It is possible to confirm the optimum charge ratio of $CO_2$ heat pump system by the viewpoint of heating COP.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.149-157
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• 2004

Implicit finite element analysis of the flat surface-straight edge hemming process is performed by using a commercial code ABAQUS/Standard. Methods of finite element modeling for springback simulation and contact pair definition are discussed. An optimal mesh system is chosen through the error analysis that is based on the smoothing of discontinuity in the state variables. This study has focused on the investigation of the influence of process parameters in flanging, pre-hemming and main hemming on final hem quality, which can be defined by turn-down, warp and roll-in. The parameters adopted in this parametric study are flange length, flange angle, flanging die corner radius, face angle and insertion angle of pre-hemming punch, and over-stroke of pre-hemming and main hemming punches.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.4
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• pp.496-505
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• 2007

This paper proposes closed-form plastic limit load solutions for elbows under in-plane bending, via three-dimensional (3-D), small strain FE limit analyses using elastic-perfectly plastic materials. A wide range of elbow and thinning geometries are considered. For systematic analyses of the effect of the axial thinning length on limit loads, two limiting cases are considered; a sufficiently long wall thinning, and the circumferential part-through surface crack. Closed-form plastic limit load solutions for wall thinning with intermediate longitudinal extents are then obtained from these two limiting cases. The effect of the axial extent of wall thinning on plastic limit loads for elbows is highlighted by comparing that for straight pipes. Although the proposed solutions are developed for the case when wall thinning exists in the center of elbows, it is also shown that they can be applied to the case when wall thinning exists anywhere within the elbow.

• Korean Journal of Agricultural Science
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• v.27 no.1
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• pp.20-24
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• 2000

External morphological characteristics of male and female of Degeeria separata, which was endoparasited in adult of the Asian ladybird, were studied by using the scanning electron microscopy (SEM). The antenna of Degeeria separata was consisted of three segment and arista. Aristae were about $750{\mu}m$ length and $30{\mu}m$ in diameter. The surface of antennae was covered with many sensilla. They were long or short, slender or thick, and straight or curved. Each three morphological types of sensilla were observed on the second and third segment of antennae. The mouthpart was sponging type. It was consisted with clypeus, labellum, labium, labrum, and maxillary palp. The labellum is $400{\mu}m$ width and double folded vertically. The leg consist of tarsus, tarsus claw, pulvilli, and empodium.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1A
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• pp.41-46
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• 2003

A MF/HF marine whip antenna with side whips, which are connected at an angle with the straight main whip, has reported In this paper, the effects of side whips on the antenna are simulated by using NEC-WIN and a novel MF/HF ship antenna with side whips is designed First of all, the gain, return loss, and radiation pattern of the antenna on infinite perfect conductor plane are simulated as function of the parameters of the side whip, such as the number, the location, the length of the side whip and the angle with the main whip. After that, the size of the antenna is decided and set up on an experimental ship in Korea Maritime University. The antenna on the ship are simulated and the simulated input impedances are good agreement with the measured results.

• Journal of the Korean Society of Clothing and Textiles
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• v.6 no.1
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• pp.39-49
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• 1982

This treatise deals with teen-agers' tendencies in selecting clothes, upon the recent liberalization measures of dress restriction. in regard to girl students' uniforms inmiddle and high schools, effective 1983. Results of my poll of 430 inquirees on the subject is outlined as follows; The surveyees have a preference for wearing box-style upper garments with a round-neck line and ribbon/tie collar. They also prefer to wear shirt cuffs mainly in set-in sleeve style. A straight skirt silhouetting the body line is anticipated to be longer in length than the knee line by 2 or 3 cm's. A dressy or sporty look would be most welcome, too. The ensemble of blue jeans and T-shirt blouse would be usual wear during school attendance. The reason why they like to choose trousers is considered to stem from the unisex look in fashion rather economical and practical purposes. Clothes material tends to be natural fabrics, single-colored and non-patterned. Color needs to be in a subdued mood, tuned with the same color and of neutral tint. In styling, emphasis is to be placed on femininity. In particular, the middle school girls wish to intensify 'Har-mony' in style while the high school misses are concerned with 'Individuality.'

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.316-321
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• 2002

The purpose of this study was to examine the effect of Ga-As(Gallium-Arsenide, wave length; 904 nm) infrared laser irradiation on healing of the experimentally crush injured rat sciatic nerves. The bilateral sciatic nerves of 43 adult male Sprague-Dawley rats were compressed surgically with a straight hemostat (1 mm width). The right legs of all the rats were irradiated using a 27 mW Ga-As infrared laser (laser irradiated group). The radiation procedure was administered for 3 minutes every day for 1, 3, 5, and 7 weeks in each group. Left legs were not irradiated and served as the control group. The numbers of total myelinated axon and degenerated myelin in the sciatic nerves of bilateral legs were measured and analyzed with mage analysis system in order to make a morphological analysis of the effect of the Ga-As infrared laser on injured nerves. Total number of myelinated axons was increased with time interval, especially in the 1, 3. and 5 week of irradiated group. Conversely, the number of degenerated myelin was decreased with time interval, especially in the irradiated group. The effects in the irradiated group were more pronounced than those of the control group. In conclusion, the Ga-As infrared laser irradiation is a useful adjuvant therapy to the regeneration of the peripheral nerve injury.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.245-250
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• 2020

Two specimens (407~438 mm in standard length) of a pleuronectid Atheresthes evermanni were collected by a gill-net from the coastal waters off Goseong-gun, middle East Sea of Korea. These specimens are characterized by a large mouth, narrow interorbital space, invisible eye at blind side, long and slender gill rakers, emarginated caudal fin, and almost straight lateral line. This is the first record of A. evermanni in Korean waters; we therefore add it to the Korean fish fauna and propose new Korean name, "Hwa-sal-chi-ga-ja-mi-sog" for the genus and "Hwa-sal-chi-ga-ja-mi" for the species, respectively.

• Journal of Fashion Business
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• v.26 no.2
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• pp.83-94
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• 2022

The purpose of this study was to analyze the reality of clothes-wearing among physically disabled women and propose trouser designs. As a research method, an in-depth interview method was adopted for 10 women in their 30s and 50s with lower limb disabilities who could wear trousers and use wheelchairs. The study results identified the following factors that should be considered in the design of trousers. First, a semi-casual design that could hide physical deficiencies, was not different from ready-made clothes and enabled various looks was desirable. Second, the proper material would have little transformation in the form, have remarkable durability and laundry fastness, two-directional stretch, and hide deficiencies with a sense of thickness and density. Third, an "L-frame" pattern in a sitting position, and a straight fit were desirable. Finally, pockets can impose pressure according to their form, size, position, and sewing method, highlighted the need for a sewing approach to minimize seams in the fabric. For adjustment, an elastic band would be a good choice in terms of type, length, position, and material as it could satisfy both the convenience of putting on and taking off and comfort in wearing at the same time. Decorative design details can also impose pressure according to a sense of thickness, which means that they should be avoided in parts that are close to the body or can impose pressure according to posture.

• Applied Microscopy
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• v.52
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• pp.6.1-6.5
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• 2022

We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07mm (n=30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5㎛. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.