• Journal of the Korean Electrochemical Society
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• v.24 no.4
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• pp.77-92
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• 2021

The energy density of lithium-ion batteries (LIBs) determines the mileage of electric vehicles. For increasing the energy density of LIBs, it is necessary to develop high-capacity active materials that can store more lithium ions within constrained weight. The rapid progress made in cathode technology has realized the utilization of the near-theoretical capacity of cathode materials. In contrast, commercial LIBs have still exploited graphite as active material in anodes since the 1990s. The most promising way to increase anodes' capacity is to mix high-capacity and long-cycle-life silicon oxides (SiOx) with graphite. However, the low initial Coulombic efficiency (ICE) of SiOx limits its content below 15 wt%, impeding the capacity increase in anodes. To address this issue, various prelithiation techniques have been proposed, which can improve the ICE of high-capacity anode materials. In this review paper, we introduce the principles and expected effects of prelithiation techniques reported so far. According to the reaction mechanisms, the strategies are categorized. Mainly, we focus on the recent progress of solution-based chemical prelithiation methods with commercial viability, of which lithiation reaction occurs homogeneously at liquid-solid interfaces. We believe that developing a cost-effective and mass-scalable prelithiation process holds the key to dominating the anode market for next-generation LIBs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.372-379
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• 2023

International oil prices are expected to increase from $85 a barrel this year to up to $100 a barrel in the second half of the year; this is likely to increase orders for offshore plants in the global market. One main characteristic of offshore plants is that a large helideck is located on the top side, and aluminum alloys are used as the basic material of the structure for weight reduction and corrosion resistance. Shipowners are increasing the size of helicopters to quickly evacuate lives in the event of an emergency, and the safety use load of devices that can stably secure helicopters to the deck is also required to increase. Owing to the nature of the aluminum material, the structural strength caused by welding is greatly reduced; therefore, the fixing device must be designed by embedding it in the deck and fixing it with bolts. In this study, a model applying aluminum alloy 6082-T6 was developed to develop a helicopter fastening device that can be used for large helidecks (diameter = 28 m). The developed item was verified through nonlinear structural strength calculation to satisfy the load used for the actual fastening condition. The load condition with a 45° showed a lower ultimate strength than the 90° case owing to local plastic collapse. The nonlinear structural collapse behavior showed a result similar to that of the experimental test. The main contents derived from this study are considered to be reference materials when evaluating the structural strength of similar aluminum equipment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.365-372
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• 2024

The South Korean marine industry is emerging as a significant market, driven by the growing popularity of various water leisure activities, including sailing. This trend suggests a rising demand for sailing yachts. Consequently, since 2022, the design and development of a 28ft sailing yacht have been ongoing, supported by the government and the Ministry of Oceans and Fisheries, to promote yachting culture in South Korea. The Velocity Prediction Program (VPP) analysis was conducted using WinDesign during the preliminary design stage to evaluate performance and determine design parameters. The hydrodynamic model used for this vessel is based on regression methods developed from years of experience in naval architecture and yacht research at the Wolfson Unit, providing reliable estimates for most modern yachts. However, owing to the lack of specific hydrodynamic data from towing tank tests or CFD numerical analysis, verification of the hydrodynamic model has faced some challenges. Additionally, an incomplete weight estimate resulted in variable VCG values, potentially affecting stability and overall performance. The optimal boat speed for this vessel was determined at true wind speeds (TWS) of 4, 8, 12, 16, and 20 knots, using both the jib (up to 120° TWA) and the spinnaker (from 80° TWA). The optimized speed of the yacht was found to be comparable to that of international similar-class yachts.

• Journal of Sericultural and Entomological Science
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• v.26 no.2
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• pp.11-15
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• 1984

To save the labour reguired for separation of copulated moth during egg Production, some of the chemicals available at the market were on screen test for easy separation of copulated moth of silkworm. The obtained results are summarized as following. 1. In a separation ratio of copulated moth along with a treating time, TCTFE(Trichloro-trifluoroethane) completely separated the copulated moth in 10 minutes. The combinations of TCTFE plus Acetone (87.5 : 12.5 V/V) and TCTFE plus Acetic acid (50 : 50 V/V) take 25minutes for the complete separation of copulated moth. Use of Acetic acid solution only makes 100% separation of copulated moth in one hour and foully minutes and non$.$treatment shows only 47.5% of separation in three and half hours. On the other hand. There is no statistical significance between TCTFE Plus Acetone and control in the egg productivity. 2. The combination of TCTFE Plus Acetone (87.5 : 12.5 V/V) does not infuluence the egg productivity of the moth, showing 443 grains for an average number of egg per moth out of which 417 grains are for the number of fertilized eggs while control shows 452 grains for an avarage number of egg/moth and 428 grains for the number of fertilized eggs. However a sing1e use of TCTFE and Acetic acid shows less egg productivity and number of ferilized eggs per moth, respectively as compared to those of the control. In particular, a single use of acetic acid makes an increase of number of non-egg prodncible moth and it seems to be brought due to a chemical damage. 3. In a rearing test of the egg laid by the chemical treated moth, there are no differences among the treatments in all of the useful characters of the larvae; larval duration, survival rate, cocoon yield, single cocoon weight, single cocoon shell weight and cocoon shell ratio. In these regards, it is recognized that TCTFE can be practically used for the separation of copulated moth and the combination of TCTFE and Acetone promote its efiectiveness on the separation of copulated moth.

• Korean journal of applied entomology
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• v.57 no.2
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• pp.97-104
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• 2018

The larva of the white-spotted flower chafer, Protaetia brevitarsis seulensis (Coleoptera: Cetoniidae), is known to have important medicinal properties, such as anti-cancer activity. However, the consumer market for the larvae is depressed because of its high production cost which needs to be reduced. This study was carried out to evaluate two spent mushroom substrates as food source for chafer larvae to improve the productivity and reduce production cost. The larvae were fed with spent substrates of king oyster mushroom (Pleurotus eryngii) (P-SMS) and shiitake mushroom (Lentinula edodes) (L-SMS), with a control of fermented oak sawdust. Effects of the diets on the development of P. brevitarsis seulensis and contents of minor nutrient components in the larvae produced were examined. In the P-SMS diet, the larval rearing period was shorter at 16.2 days, while the rate of larval weight gain and the cocoon weight were higher at 156.3% and 4.1 g, respectively, than that in the L-SMS diet. The pupation rate was 100% and the adult emergence was higher at 93.3% in the P-SMS diet than in the L-SMS diet with no difference to the control diet. In the P-SMS diet, the total nitrogen content during rearing was higher at 10.28% and the minor nutrient component, particularly Fe (145.8 mg/kg), was higher than that in other diets. The oviposition preference of adults showed no significant difference among the diets. Economic analysis showed that P-SMS costs approximately 667,960 Won less per 100 kg of larvae produced, compared to that of the control diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.563-568
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• 2007

We report that the gamma linolenic acid content of pork is higher in finishing pigs fed diets containing hemp seed oil, evening primrose oil or borage oil as the sources of gamma linolenic acid. Thirty-six three crossing swines ($Landrace{\times}Yorkshire{\times}Duroc$), 80 kg in body weight, were randomly separated into four treatment groups with three pens per treatment and three animals per pen. The finishing swines were fed the experimental diets for 35 days until they reached the market weight of 110 kg. The animals were assigned to the four experimental diets: control diet containing 5.00% tallow, T1 containing 5.00% hemp seed oil (hemp seed oil 40:soybean oil 60), T2 containing 5.00% evening primrose oil (primrose oil 40:soybean oil 60) and T3 containing 5.00% borage oil (borage oil 40:soybean oil 60). The plasma triacylglycerol and total cholesterol content of the swine in the gamma fatty acids-fed groups were significantly (p<0.05) lower than those in the control group. No gamma linolenic acid was detected in the plasma of the control group, while tile level of gamma linolenic acid treatment groups was significantly (p<0.05) higher than the control in the order of T3, T2 and T1. Moreover, the level of gamma linolenic acid increased with increasing number of feeding days. There was a significant difference between the treatment groups (p<0.05). There was a difference in the amount of saturated fatty acid and polyunsaturated fatty acid accumulated in the pork according to the treatment groups or the parts of the pork meat. The level of n-3 fatty acid of pork was highest in T1, which had been fed the hemp seed oil, followed in order by T3 and T2 (p<0.05). The content of gamma linolenic acid in pork was highest in T3, which had been fed the borage oil, followed in order by T2 and T1 (p<0.05). In particular, the level of gamma linolenic acid in pork increased in the order of the back fat, pork belly, ham and loin.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.1
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• pp.35-40
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• 2015

Effect of packaging and storage methods for enhancing the shelf life and improving the postharvest quality of lettuce (Lactuca sativa L.) was studied during high temperature period. Lettuces were packed using four packaging and storage types: (A) plastic box container (control); (B) plastic box container covered with high density polyethylene (HDPE) film; (C) plastic box container with lettuce wrapped in linear low-density polyethylene (LLD-PE) film; and (D) plastic box container with lettuce with its stem. The quality parameters, such as fresh weight loss, SPAD value, and appearance of lettuce were investigated. The lettuce wrapped with LLD-PE film inside the plastic box container showed the lowest weight loss, highest SPAD value and best appearance compared to those exposed to the other packaging and storage methods during the three-week storage at $2^{\circ}C$. The results indicate that the marketability of lettuce can be optimized if proper packaging and storing is adopted. Prolonging the freshness even on low temperature storage will increase the potential of its sale ability in the domestic market even during summer season.

• Research in Plant Disease
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• v.14 no.1
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• pp.21-25
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• 2008

This study was conducted to decide disease incidence level of rice leaf blast required for reasonable fungicide application in paddy field. We induced the disease development by inoculating rice blast pathogens on rice seedlings (Jinmibyeo) in the greenhouse and transplanting the infected seedlings in the field two weeks after rice plants were transplanted. We scored the disease incidence, grouped and marked according to degree of percentage of diseased leaf area at maximum stage of disease development. The percent diseased leaf area (PDLA) had negative correlations with panicle number per hill, ripened grain (%), and total yield; their correlation coefficients (r), $-0.97^{**}$, $-1.00^{**}$ and $-0.96^{**}$, respectively. However, it had positive correlations with spikelets per panicle and thousand grain weight; their correlation coefficients (r), $0.98^{**}$ and $0.98^{**}$, respectively. Gain threshold (GT) calculated based on control cost and market price was estimated to be 8.35. Economic injury level (EIL) obtained based on GT and coefficient of damage of regression equation between disease incidence and the different yield components; panicle number per hill, spikelets per panical, ripened grain(%), thousand grain weight and yield were 41.8, 9.7, 19.1, 291.1 and 3.4%, respectively. Economic threshold (ET) for yield was 2.7% ($3.4%(EIL){\times}0.8$) on PDLA. These results suggest that application of fungicide is necessary when two under leaves are almost covered with lesions or contained more than twenty large lesions under leaves at maximum tillering stage.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.178-184
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• 2019

Strawberry ($Fragaria{\times}ananassa$) is one of the most important and popular fruit crops in the world, and 'Sulhyang' is one of the principal cultivars cultivated in the Republic of Korea for the domestic market. The growth and flower induction in strawberry is the process which influences directly on fruit bearing and yield of this crop. In this study, effect of benzyladenine (BA), gibberellic acid ($GA_3$), and salicylic acid (SA) on growth and flower bud induction in strawberry 'Sulhyang' was investigated. The 3-week-old runner plants, grown in 21-cell propagation trays, were potted and cultivated in growth chambers with $25^{\circ}C/15^{\circ}C$ (day/night) temperatures, 70% relative humidity (RH), and light intensity of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density (PPFD) provided by white light emitting diodes (LEDs). The runner plants were treated with one of three concentrations, 0 (control), 100, and $200mg{\cdot}L^{-1}$ of BA, $GA_3$, or SA solution. The chemicals were sprayed two times on leaves of runner plants at an interval of two weeks. After 9 weeks the results showed that the application of all chemicals caused reduction of root length and chlorophyll (SPAD) content as compared to the control. The lowest chlorophyll (SPAD) content was recorded in plants treated with $GA_3$. However, the treatment of $200mg{\cdot}L^{-1}$ $GA_3$ promoted leaf area, leaf fresh weight, and plant fresh weight. The greatest flower induction (85%) and number of inflorescences (4.3 inflorescences per plant) were observed in the treatment of $200mg{\cdot}L^{-1}\;SA$, followed by $100mg{\cdot}L^{-1}\;SA$. Overall, results suggest that foliar application of $GA_3$ solution could accelerate plant growth, while foliar application of SA solution could induce hastened flowering. Further studies may be needed to find out the relationship between $GA_3$ and SA solutions treated in a combination, and the molecular mechanism involved in those responses observed.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.2
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• pp.115-125
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• 2022

The purpose of this study was to examine the effect of packaging on quality maintenance of paprika (Capsicum annuum L. cv. Nagano RZ) stored at three different temperatures. In Korea, paprika is stored and distributed under ambient conditions. To ensure the freshness maintenance, determining optimal storage temperature is necessary. Paprika were unpacked (control) or packed with polyamide film and stored at 5℃, 10℃ and 20℃ for 35 days. Quality characteristics such as weight loss and appearance were examined. Paprika packed with polyamide film showed less quality changes compared to unpacked paprika under all the storage temperatures. The commercial properties tended to decrease rapidly during storage at 20℃ regardless of packing. The degree of weight loss was significantly lower in packed paprika compared to unpacked paprika. It was found that soluble solids, pigments, hardness, etc. were complexly affected by storage temperature and film packaging. For paprika, the storage temperature of 5℃ or 10℃ was effective in maintaining freshness; paprika packed in polyamide film packing maintained greater freshness than unpacked paprika. Our results showed that, packaging is required to preserve the freshness and to improve the marketability of paprika in the domestic market. It seems that it is necessary to continuously search for an effective packaging method.