• Horticultural Science & Technology
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• v.31 no.3
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• pp.308-316
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• 2013

Fresh ginseng has a limited storage life due to the quality change caused by microbial spoilage as well as physiological deterioration. The present study investigated the effects of 1-methylcyclopropene (1-MCP) treatment, an inhibitor of ethylene action, on the microbial growth and quality maintenance of fresh ginseng during storage. Harvested fresh ginsengs were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 20 hours at $4^{\circ}C$ and then stored at room temperature (RT) for 18 days or low temperature ($4^{\circ}C$) for 160 days. After 18 days of storage at RT, the percentage weight loss in 1-MCP treated fresh ginseng (8.3%) is lower than that of control (10.1%). During long-term storage at $4^{\circ}C$, weight losses were increased slightly until 120 days without difference between non-treated and 1-MCP ginsengs. In contrast, after 120 days of storage at $4^{\circ}C$, higher increase in weight loss was observed in non-treated ginsengs than in 1-MCP treated ginsengs. Respiration rate and ethylene production of fresh ginseng were reduced by 1-MCP treatments at RT. The 1-MCP treatment also resulted in lower microbial population compared to those of non-treated ginsengs at RT. However, in ginsengs stored at $4^{\circ}C$ for short-term (45 days), no differences were noted in weight loss and microbial population between 1-MCP treated and non-treated ginsengs. Major ginsenosides was not changed by 1-MCP treatment during the 7 days of storage at RT. Results suggest that 1-MCP treatment can be used to maintain the freshness of ginseng at room temperature for short term storage and at low temperature for long term storage. 1-MCP treatment could be applied on fresh ginseng to avoid deleterious effect of exogenous ethylene during storage and shipping.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.569-579
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• 2005

An investigation for long-term strength characteristics of crushed sand concrete using crushed sands produced in Yang-san, Kim-hae and Jin-hae that can be assumed to respectively represent eastern, middle and western suburbs of Busan has been carried out. Concrete is composed of 70~80% of aggregates in whole volume so the effect of aggregates quality to the characteristics of concrete is very important. Since 1980s, aggregates used in concrete have already been substituted crushed stone because of the exhaustion of natural gravel and sand. Crushed sand tends to increase in using quantity because of the prohibition of sea sand picking and deterioration of river sand. Crushed sand is blended with river sand in order to investigate the quality changes and characteristics of concrete as variation of blend ratio of crushed sand (n, 50, 70, 80, 90, 100%). Slump and air content were measured to investigate the properties of fresh concrete. Unit weight, compressive strength and modulus of elasticity in age of 7, 28, 60, n, 180 days were measured to investigate properties of hardened concrete. Compressive strength, unit weight and modulus of elasticity were increased with a passage of time and they are expected to keep on increasing in long-term age as well. The experimental results of the qualifies of crushed aggregates in each producing area, were all satisfied with Korea Standard. The results of the measurement of slump exposed that slump preferably decreased as mixing rate increased till 70~80% but it increased to mixing rate 70~80%. The air content was exposed that it decreased by micro filler phenomenon according to that crushed sand b)ended ratio increased. According to the result of measuring unit weight in age of 7, 28, 60, 90, 180days, it increased in accordance with that blended ratio of crushed aggregates increases. As a result of measuring compressive strength and modulus of elasticity in age of 7, 28, 50, 90, 180days, compressive strength was highest when it is 70% of blended ratio.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.6
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• pp.520-529
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• 2016

The main purpose of this study was to analyze the performance of a medium-altitude long endurance unmanned aerial vehicle through reverse-engineering method. The external configuration data of the RQ-1 Predator was reverse-engineered from related photos and specification data available on public domains, which also were used to generate the CATIA modeling and weigh distribution data of the UAV. The aerodynamic characteristics of RQ-1 Predator were mainly predicted the vortex lattice method and an empirical method, which the propeller performance was analyzed by the empirical method proposed by Howe. The rate of climb, service ceiling, range, and the loiter endurance of the UAV was analyzed, which showed good agreement with the reference data.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.482-489
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• 1996

Dried-red pepper, whole and powdered types, was subjected to a storage-study by investigation the effects of packaging methods (polycloth & polyethylene/polycloth, whole dried-red pepper; nylon/polyethylene-lam-inated film, red pepper powder), temperature (ambient, $5{\sim}10^{\circ}C$) and gamma irradiation doses (0-10 kGy). After 6 months storage in polyclith sack at ambient temperature, all whole dried-red pepper showed quality deterioration, such as weight change, insect infestation, discoloration and chemical changes, After 2 years storage in combined packaging with polyethylene/polycloth sack of 5-7.5 kGy irradiated whole dried-red pepper at ambient temperature, however, quality deterioration was not observed. Gamma-irradiated red pepper powder (7.5-10kGy) showed a good quality in hygienic, physicochemical and organoleptic evaluation after 2 years of storage at ambient temperature.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.1-9
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• 2013

In order to increase endurance flight efficiency of long endurance electric powered UAV with solar cell, the light weight airframe design techniques are important. In this paper, the design of the main wing of electric powered UAV manufactured using Mylar film and fiber reinforced composite was conducted in order to achieve weight reduction and structural integrity of the structure. The shape of spar and size were determined using beam theory analysis. The finite element analysis of the wing was performed under various load condition derived from flight environment of EAV-2H. Finally, the static strength test of the main wing was conducted to verify structural integrity. It was found that the developed main wing weigh less than 42% than the previous EAV-2 and the main wing passed static strength test under ultimate load.

• Journal of the Society of Disaster Information
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• v.8 no.4
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• pp.391-400
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• 2012

Recently, the construction industry commonly uses FRP as a reinforcement material because of its material advantages. FRP attached reinforcement has various advantages such as high strength, stiffness, excellent durability and construction practicability comparing to its weight. However, external attachment of FRP is water-tighted with low water permeable material, not draining water, probably causing damages on a permanent structure. The study manufactured it through pultrusion and examined GP(glass fiber panel) of which material-mechanical properties are almost same as the existing FRP but durability and attachment performance are better by stationary experiments, testing load-deflection curve, destruction types and load-deflection relation under repetitive loading test. As a result of 2,000,000 fatigue tests, it did not result in the destruction and showed excellent permanent attachment and durability as it displays significantly low compressive strain of concrete.

• Journal of Radiation Protection and Research
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• v.37 no.3
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• pp.159-166
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• 2012

The present study was performed to investigate the toxicity of low-dose-rate irradiation in BALB/c mice. Twenty mice of each sex were randomly assigned to four groups of five mice each and were exposed to 0 (sham), 0.02, 0.2, or 2 Gy, equivalents to low-dose-rate irradiation to 3.49 $mGy{\cdot}h^{-1}$. Urine, blood, and blood biochemistry were analyzed, and organ weight was measured. The low-dose-rate irradiation did not induce any toxicologically significant changes in mortality, clinical signs, body weight, food and water consumption, urinalysis, and serum biochemistry. However, the weights of reproductive organs including the testis, ovary, and uterus decreased in a dose-dependent manner. Irradiation at 2 Gy significantly decreased the testis, ovary, and uterus weights, but did not change the weights of other organs. There were no adverse effects on hematology in any irradiated group and only the number of neutrophils increased dose dependently. The low-dose-rate irradiation exposure did not cause adverse effects in mice at dose levels of 2 Gy or less, but the reproductive systems of male and female mice showed toxic effects.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.342-350
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• 2008

This study was carried out to investigate the suitability of the pubertal assay and the enhanced TG 407 as methods for detection of endocrine-mediated effects. Thyroid function was also considered. Male and female Sprague-Dawley rats were gavaged daily with 0, 25, 50, 100 mg/kg metribuzin in corn oil during 30 days. The effects of metribuzin on thyroid gland, the genital organs and thyroid hormone were measured in male and female rats. Dose of metribuzin 50 mg/kg/day increased relative weight of testis, prostate, and seminal vesicle in male rats but relative weight of thyroid gland was not significantly different from control group. Dose of metribuzin 25 mg/kg/day decreased relative weight of thyroid gland in female rats. Another purpose of this study was to investigate the effects of endocrine-disruptors as like thyroid hormone in vitro. Luciferase activity was measured to detect reaction of test chemicals and thyroid hormone response elements in HeLaTRE cell. Dose of metribuzin from 1 to 1,000 nM increased to 106-122% of luciferase activity.

• Food Science and Preservation
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• v.9 no.1
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• pp.8-13
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• 2002

The effects of modified atmosphere (MA) storage far fresh red pepper and red bell pepper fruits were investigated with storing in high and few density polyethylene films (HDPE, LDPE) with various NaCl contents(0 g, 15 g, 20 g, 25 g). During the storage of pepper fruits, the weight loss, color change, mold emergence, and firmness were evaluated. The weight loss of pepper fruits packaged in HDPE and LDPE without NaCl was 3∼5%, even though it was 6∼19% in pepper fruits packaged with NaCl. The lutes of mold emergence of red pepper and red bell pepper fruits were lowered to 20∼45% as stored in HDPE and LDPE with NaCl but those of fruits stored in films without NaCl were high as 55∼65%. The color and firmness of pepper fruits were not much changed in comparison with those of non-packaged fruits as stored in HDPE and LDPE with or without NaCl.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.964-966
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• 2002

This paper presents a magnet circuit design procedure to reduce mover mass of the moving coil type linear direct motor (LDM). The procedure of optimization is based on the response surface methodology (RSM) and Sequential Quadratic Problem (SQP). This procedure of optimization is verified by the comparison of the result of the initial design between the result of the optimum design.