• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.733-739
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• 2004

Model for optimally dimensioned PE film bag was developed according to fruit size to maintain best quality of 'Fuyu' persimmon in modified atmosphere packaging (MAP) storage based on relationship between quality and oxygen and carbon dioxide in PE film bag. Harvested persimmons were graded into five sizes, and average weights were LL:261, L:217, M:188, S:168, and SS:154 g. Five fruit units of each grade were optimized in five PE film bag sizes of $150{\times}376,\;140{\times}357,\;130{\times}344,\;130{\times}333,\;and\;120{\times}3l8\;mm$. To minimize quality deterioration such as softening and discoloration, optimal oxygen and carbon dioxide concentrations in PE film bag were 0.5-1.0 and 6.0-8.0%, respectively, and optimal thickness of PE film bag according to fruit size were LL:45, L:50, M:55, S:60, and $SS:65\;{\mu}m$. For all fruit sizes, model for PE film bag area $(mm^2)$ was good quadratic simple equation by fruit weight (g): $Y=-4055.707+627.993X_1-0.701{X_1}^2$. Model far optimal oxygen and carbon dioxide (Y) concentration in PE film bag was suited to linear multiple equation by fruit weight $(X_1,\;g)$ and PE film thickness $(X_2,\;{\mu}m)$. Equations for oxygen and carbon dioxide concentrations (%) were $Y=5.798-0.0109X_l-0.0491X_2\;and\;Y=-2.427+0.01927X_l +0.09646X_2$, respectively.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.84-93
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• 2010

Compaction of backfill material of Underground power lines is difficult, especially under pipeline. so it could cause structural problem because of low compaction efficiency. So various methods have been taken to solve the problem and one of them is CLSM(Controled low-strength material accelerated flow ability). But In other countries, these are already in progress for a long time to research and development and recently on practical steps. But, in our country, study for only general structures, not for underground power line structure that is being constructed at night rapidly. In this study, we performed property tests and indoor & outdoor test (3 cases). The tests showed flow ability reached at the limit construction(160 mm) flowability by 9 to 15 minute after starting to mix, and construction buoyant is lowering after placing CLSM by 70 % of theoretical buoyant that is calculated by unit weight of material. In this paper, we performed indoor tests and outdoor tests to estimate mechanical properties and to suggest construction method(using batch plant, setting spacer at 1.8 m and placing at 2m) for CLSM that using surplus soil. And the test showed good results for construction quality, workability and structure safety.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.812-817
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• 2011

Rolling stocks are often subjected to the effects of natural cross wind or train wind pressure due to the crossing train. These wind pressure cause the falling-off in running stability and turnover problem. It is sometimes reported that trains are blown over by a gust of wind in overseas. So, many countries enact regulations to secure the safety for wind speed. In this study, we analyzed the difference between the regulation for turnover safety of train which was enacted by Ministry of Land. Transport and Maritime Affairs and that based on the multi-body model. In case of multi-body model, it is assumed that the degrees of freedom for carbody and bogie are assigned an independent values respectively. The results show that the latter approach based on multi-body model can access the safety of turnover and replace the computational method which is accessing with lateral force, derailment coefficient and decrement of wheel load.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1068-1077
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• 1994

Blend samples of biodegradable copolyesterethylene(CPEE) with LDPE were prepared by melt-mixing through 0 to 100% per 10% interval for studying of common use of biodegradable polymer. Miscibility behavior of blend samples has been studied by observing the melting temperature change, melting enthalpy, cold crystallization temperature and crystallization enthalpy using differential scanning calorimetry. It was shown that 10~30% blend composition of CPEE had the partial miscibility from the results of thermal analysis. Valuable compatibility has been observed in all blend composition except the samples of 30~80% CPEE component from results of mechanical properties. Morphology of blends has been observed with scanning electron microscopy. Biodegrability of CPEE/LDPE blends has been evaluated by measuring the change of weight after the inoculation with specific microorganism.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.731-738
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• 2017

Twin-hulls frequently incur structural damage at connecting members between the hull and deck induced by pitching motions during voyages. so, reasonable reinforcement is necessary around vulnerable spots such as corner knuckle, the chine bottom and inner hull. Since guidelines for structural design are not clear, engineers often respond by reinforcing plate thickness, changing stiffener sizes and reducing frame spacing, etc. These members constitute about 85 % of the longitudinal dimensions of the ship, so it is necessary to locally reinforce certain points to minimize weight stress, and also solve construction cost problems while securing the freeboard margin. Therefore, we developed a new program by analyzing the structural design procedures for the twin car-ferries based on Korean Register of Shipping (KR) High Speed Craft Rules, identifying items that need to be added. In order to ensure the reliability of buckling estimations for procedures and design programs, we conducted a comparative study with other standards and confirmed that differences were minimal.

• The Korean Journal of Zoology
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• v.29 no.3
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• pp.201-207
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• 1986

The authors attempted to investigate the oxygen consumption rate of sexuals in the water-striders, Gerris paludum insuralis, at four temperature groups of 25, 30, 35 and $40^\\circ C$ in a series of studies on respiration of a heminetabolous insects. THe results are summarised as follows: (1) At $30^\\circ C$, the change of oxygen consumption rate according to the lapse of time was small in comparison with the other three temperature groups which shows a cyclic decreasing pattern. The rate during initial and final 5 minutes was much alike. Thereupon, the optimum temperature was regarded as $30^\\circ C$. (2) The oxygen consumption rate of male was higher than that of female. (3) The oxygen consumption rates at 25, 30, 35 and $40^\\circ C$ were 0.42, 0.49, 0.79 and 1.11 $\\mu$l/mg/h respectively. That is, the rate was increased as the temperature was increased. (4) The $Q_10$ of male showed a high value in the lower temperature interval ($25^\\circ C \\sim 35^\\circ C$), but the female showed a high value in the higher temperature interval ($30^\\circ C \\sim 40^\\circ C$). The mean $Q_10$ was 2.12. (5) The respiratory rate was decreased as the body weight was increased in the above fresh weight of 10mg and dry weight 5 mg. (6) The upper temperature threshold for respiration was $48.31^\\circ C$ and the lower temperature threshold was $17.68^\\circ C$. (7) The ceasing time of breathing at the other three temperature groups except $30^\\circ C$ was infered to be about 110 minutes after the start of experiment.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.9-18
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• 2019

Concrete, which is the most widely used building material in modern times, has been improved not only in strength but also in structural performance such as increase in toughness and ductility, weight reduction, and improvement in quality of human life. Due to the surge in demand for the building, there is a tendency to be used variously from architectural panel and architecture to interior accessories. In Korea, a light-transmitting concrete, LEFC(Light Emotion Friendly Concrete), that insert plastic rods to stimulate emotional sensation through the combination of light and concrete has developed. In previous research, it was confirmed that the use of a synthetic foam agent rather than an animal foam agent did not cause a fogging phenomenon. In this study, lightweight by applying foaming agent to LEFC and two types of fiber (Nylon Fiber, Polyvinyl Alcohol) were compared to achieve to investigate the fiber to be applied in future. An equation that can predict the loss and adhesion reduction of the concrete section according to the diameter of the rod (5mm, 10mm) and the interval (10mm, 15mm, 20mm) was proposed.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.34-44
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• 1990

The study was carried out to elucidate the effects of ovarian function on the thyroid gland, adrenal gland and uterus in female rats. One hundred and forty-four mature female rats were allotted into the three groups ; ovariectomized group, estradiol treated group and intact control group. The ovaries of 48 heads of rats were completely removed. Forty eight heads of rats were administered with $200{\mu}g$ of estradiol benzoate every 48 hours. Serum estradiol-$17{\beta}$ and progesterone levels were determined with radioimmunoassay method at 3, 6, 12, 24 hours and 5, 10, 15 days after treatment. The rats were necropsied to measure weights of thyroid gland, adrenal gland and uterus and to examine the histological changes in the organs. The results obtained were as follows ; 1. Serum estradiol-$17{\beta}$ levels were rapidly decreased below 27.20pg/ml 18 hours after ovariectomy. In estradiol treated rats the levels were rapidly increased 18 hours after treatment, but thereafter slowly decreased. The significant differences in the estradiol level were found between the group at every observation time. 2. Serum progesterone levels were significantly decreased after ovariectomy and estradiol injection. The lowest level was found in the group of ovariectomized rats. 3. The weights of thyroid glands decreased in ovariectomized rats rather than in intact rats 5 days after treatment. The weights tended to increase after estradiol injection but significant differences between the groups were seen on 10th and 15th days. 4. In the histological findings of thyroid glands, follicular epithelial cells were changed to be squamous 5 days after ovariectomy and accompanied pyknosis 10 days and karyorrhexis 15 days after ovariectomy. On the contrary follicular epithelial cells were changed to be columnar with hypertrophy 10 days after estradiol injection. 5. The significant differences in adrenal gland weights were recognized between all the groups 5 and 15 days after treatment in ovariectomized rats were lighter than intact rats and the adrenal gland weights were rather heavier in estradiol treated rats. 6. The days after ovariectomy the adrenal glands were atrophied accompanying with pyknosis in the cortical cells of zona fasciculata. The cells in zona fasciculata and zona reticularis started to hypertrophy 5 days after estradiol injection, but no changes were found in the zona glomerulosa of adrenal cortex and in the adrenal medulla. 7. The significant differences in uterus weights were recognized between the groups at each observation time. After ovariectomy the uterus weights decreased rapidly but after estradiol injection they increased rapidly. 8. Through histological examination of uterus, the atrophy and degeneration started to occur in endometrium and lamina propria 12 hours after ovariectomy, and in myometrium one day after ovariectomy, and the changes progressed rapidly after that. On the contrary, the myometrium was proliferated and hypertrophied from 12 hours after estradiol-$17{\beta}$ injection.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.529-536
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• 2011

Recently, there has been a growing interest in expanded sidewalks for existing bridges. The cantilever beam system applied to expanded sidewalks for existing bridges are connected with the concrete structure by adhesive anchor bolts. However, the extended sidewalks are currently constructed without standardized regulations, which lead to excessive design of the beam spacing and installation and the construction difficulties due to the excessive over-weight. Moreover, there is only limited analysis and experiment data on the post-installed adhesive anchor bolts, so the excessive number of bolts is used for the connection. This paper deals with a method to increase the effectiveness of beam sections and anchor bolts geometry for expanded sidewalk of existing bridge. The study results showed that the failure of cantilever beam connected by adhesive anchor bolts was dominated by bond failure of interface between concrete and bolt. Also, the results indicated the possibilities of improving serviceability as well as safety of the sidewalks by changing of beam section and prestressing the bolts.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.4
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• pp.17-24
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• 2010

The hollow RC(Reinforced concrete) pier has the merit of lightweight pier compared with solid RC pier. However, the hollow RC pier shows a low ductile behavior due to brittle failure of inside concrete. To overcome this problem, the internally confined hollow reinforced concrete column has been developed. In this study, the behavior of internally confined hollow RC piers were evaluated with safety ratio, ductility, total material cost, the total weight of the pier, etc. The chosen parameters for the study are hollow ratio, thickness of internal steel tube, intervals between vertical re-bars, numbers of horizontal re-bars, and strength of concrete. As a result of parameters study, the usage of a minimum necessary thickness of the internal steel tube is the most effective.