• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.1
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• pp.27-35
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• 2017

In this study, an integrated 2-in-1 transformer for a low-weight and low-cost light-emitting diode lighting power supply is proposed. In the transformer, a power factor correction (PFC) inductor and an LLC resonant transformer are placed and integrated on a single magnetic core. The amount of mutual interference, represented by the coupling coefficient, between magnetic fluxes generated from each magnetic source is minimized by using the new shape core of an integrated 2-in-1 transformer. The design consideration on critical conduction mode PFC converter and LLC resonant converter using the proposed 2-in-1 integrated transformer is described, and the overall performance of the 150 W LED PSU shown through the experiment.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1099-1106
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• 2017

In this paper, a three phase inverter control methodology for photovoltaic generation system, which is a renewable energy source, was studied. The voltage source inverter type of the constant voltage supply type was selected as the three phase photovoltaic inverter, and SWPM method was selected as control technique. a small capacity three phase photovoltaic inverter system, which has a DSP with powerful high speed data processing ability as the main controller and a solar controller as current controller to supply a certain amount of current to charge the battery, was made and tested for SPWM function.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.412-417
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• 2004

In urban rail transit systems, ground faults in the DC traction power supply system are currently detected by the potential relay, 64P. Though it detects the fault it cannot identify the faulted region and therefore the faulted region could not be isolated properly. Therefore it could cause a power loss of the trains running on the healthy regions and the safety of the passengers in the trains could be affected adversely. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. A current limiting device, called Device X, is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. One type of the relaying schemes is called directional and differential ground fault protective relay which uses the current differential scheme in detecting the fault and uses the permissive signal from neighboring substation to identify the faulted region correctly. The other is called ground over current protective relay. It is similar to the ordinary over current relay but it measures the ground current at the device X not at the power feeding line, and it compares the current variation value to the ground current in Device X to identify the correct faulted line. Though both type of the relays have pros and cons and can identify the faulted region correctly, the ground over current protective relaying scheme has more advantages than the other.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.411-415
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• 2008

This paper presents on design factor considered in an altitude test cell facility to determine the best sizing to optimize exhaust diffuser pressure recovery and the exact cooling load required to be supplied under transient operation. Engine simulation was performed to analyse the exhaust gas temperature, exit mass flow rate, specific fuel consumption and exhaust velocity helpful in determining secondary mass air flow and the mixed air temperature entering the ejector. based on this, the amount of cooling load was deduced. It was found that improved pressure recovery reduces operational cost(air supply facility, cooling water).

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.376-387
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• 2019

Melons are mostly grown in soil, but it is susceptible to damage due to injury by continuous cropping such as Fusarium wilt and root rot. Hydroponic cultivation system can overcome the disadvantages of soil cultivation with precise nutrition management and a clean environment. When using the coir substrate, the most environmentally friendly organic substrate used for hydroponics, it is analyzed how the growth and fruit quality of the melon depends on the ratio of chips and dust and the amount of irrigation. The purpose of this study was to provide the basic data of melon hydroponics when cultivated in spring. The two types of the coir substrates used in the experiments were chip and dust ratios of 3 :7 and 5 : 5 respectively. The substrate with high dust ratios had excellent physical characteristics, such as container capacity and total porosity, and the drainage EC level showed a high value of $3.0-6.8dS{\cdot}m^{-1}$. When the amount of irrigation is provided based on the drainage rate, the group provided the nutrient solution on the basis of 10% drainage supplied 91 L per plant, which was reduced by about 30% compared to the group with the highest water supply. In addition, the total drainage showed less than 10 L per plant with a minimum water supply and was reduced by 30 - 70% in substrate with a high dust rates. In substrate with high water supply and high dust ratio, leaf growth and fruit enlargement were good, and the soluble solids content varies greatly from cultivar to cultivar. If you provided the amount of irrigation based on 10% drainage rate, the fruit weight will be decreased, but the amount of irrigation can be reduced. Therefore, it is considered that managing the water & nutrient properly taking into account the characteristics of coir substrate and cultivar can produce melon of uniform quality using hydroponics.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.343-352
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• 2012

Sulphur deficiency has become widespread over the past several decades in most of the agricultural area. Oilseed rape (Brassica napus L.) is a very sensitive to S limitation which is becoming reduction of quality and productivity of forage. Few studies have assessed the sulphur mobilization in the source-sink relationship, very little is known about the regulatory mechanism in interaction between sulphur and nitrogen during the short-term sulphur deficiency. In this study, therefore, amount of sulphur and nitrogen incorporated into amino acids and proteins as affected by different S-supplied level (Control: 1 mM ${SO_4}^{2-}$, S-deficiency: 0.1 mM ${SO_4}^{2-}$, and S-deprivation: 0 mM ${SO_4}^{2-}$) were examined. The amount of sulphur in sulphate (S-sulphate) was significantly decreased by 25.8% in S-deprivation condition, compare to control, but not nitrogen in nitrate (N-nitrate). The markedly increase of sulphur and nitrogen incorporated amino acids (S-amino acids and N-amino acids) was observed in both S-deficiency and S-deprivation treatments. The amount of nitrogen incorporated proteins (N-protein) was strongly decreased as sulphur availability while the amount of sulphur incorporated into proteins (S-protein) was not affected. A highly significant ($p{\leq}0.001$) relationship between S-sulphate and S-amino acid was observed whereas the increase of N-amino acids is closely associated with decrease of N-proteins. These data indicate that increase of sulphur and nitrogen incorporated into amino acids was from different nitrogen and sulphur metabolites, respectively

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.275-279
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• 1977

During the experimental rearing period of common carp in a small simple recirculating aquarium combined with frequent exchanges of water and cleanings, some observations were made on the conditions of fish growing which was directly and instantly affected by the cleaning frequency of strainer, changing rate of water, division and frequency of feed supply, prohibition of excess feeding and the amount of dissolved oxygen. The fish don't seem to be stressed by the manipulation for the change of rearing water, cleaning of detritus in the strainer and filter. It appeared that the most hazzardous matters to fish growth were : 1) supplying feed when fish do not show active response to feed supplied, and 2) giving ample amount of feed at one time. When especially the amount of the feed is within the range fish instantly can swallow, the water clarity is maintained even after feeding operation, but if any excess amount is given the fish intake into mouth much more feed than able to instantly swallow and try to swallow it resulting in much dissolving and suspension of feed materials in water, making the water quite cloudy. Consequently all the water as well as filter bed becomes significantly polluted.

• The Korea Journal of Herbology
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• v.32 no.2
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• pp.1-16
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• 2017

Objective : The study was for researching the activation methods about Korean overall medical crops business from 2010 to 2016. In addition, it was to be given to examining complement points and improving methods to the changeable domestic market of medical crops caused by a considerable export-import amount of them. Methods : By examining and analyzing data for the trend of medical crops production and their export-import trend from 2010 to 2015, I found it valuable to use it as the basic resources for researching the urgent problem of medical crops' business and its improvement. Results : 1. As surveying the trend of the domestic medical crops over the recent six years, I found that the export amount of them has drastically decreased, while the import amount has increased. And so, the prices of the domestic medical crops and their production are unstable. 2. By developing standardized medical crops which a trading counterpart country could prefer, we have to promote the export competitiveness. 3. We should reinforce an origin mark and geographical mark practice for domestic herbal materials and expand GMP. 4. We should prepare a standardization of herbal medicines by setting up an independent governmental department. Conclusion : 1. The government should present an appropriate supply-demand amount of the medical crops depending on the domestic needs and the export-import transactions. 2. There should be an institutional supportive system which is able to guarantee stable incomes of farmers through contract cultivation. 3. We should develop high value standardized medical crops.

• Fashion & Textile Research Journal
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• v.25 no.6
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• pp.673-689
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• 2023

To realize the traceability of sustainable textile products, this study presents a low-carbon process through energy savings in the textile material manufacturing process. Traceability is becoming an important element of Life Cycle Assessment (LCA), which confirms the eco-friendliness of textile products as well as supply chain information. Textile products with complex manufacturing processes require traceability of each step of the process to calculate carbon emissions and power usage. Additionally, an understanding of the characteristics of the product planning-manufacturing-distribution process and an overall understanding of carbon emissions sources are required. Energy use in the textile material manufacturing stage produces the largest amount of carbon dioxide, and the amount of carbon emitted from processes such as dyeing, weaving and knitting can be calculated. Energy saving methods include efficiency improvement and energy recycling, and carbon dioxide emissions can be reduced through waste heat recovery, sensor-based smart systems, and replacement of old facilities. In the dyeing process, which uses a considerable amount of heat energy, LNG, steam can be saved by using "heat exchangers," "condensate management traps," and "tenter exhaust fan controllers." In weaving and knitting processes, which use a considerable amount of electrical energy, about 10- 20% of energy can be saved by using old compressors and motors.

• Proceedings of the Korean Society of Crop Science Conference
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• 2007.04a
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• pp.65-73
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• 2007

The objective of this study is to understand how regulatory mechanisms respond to sugar status for more efficient carbon utilization and source-sink regulation in plants. So, we need to identify and characterize many components of sugar-response pathways for a better understanding of sugar responses. For this end, genes responding change of sugar status were screened using Arabidpsis cDNA arrays, and confirmed thirty-six genes to be regulated by sucrose supply in detached leaves by RNA blot analysis. Eleven of them encoding proteins for amino acid metabolism and carbohydrate metabolism were repressed by sugars. The remaining genes induced by sugar supply were for protein synthesis including ribosomal proteins and elongation factors. Among them, I focused on three hydrolase genes encoding putative $\beta$-galactosidase, $\beta$-xylosidase, and $\beta$-glucosidase that were transcriptionally induced in sugar starvation. Homology search indicated that these enzymes were involved in hydrolysis of cell wall polysaccharides. In addition to my results, recent transcriptome analysis suggested multiple genes for cell wall degradation were induced by sugar starvation. Thus, I hypothesized that enzyme for cell wall degradation were synthesized and secreted to hydrolyze cell wall polysaccharides producing carbon source under sugar-starved conditions. In fact, the enzymatic activities of these three enzymes increased in culture medium of Arabidopsis suspension cells under sugar starvation. The $\beta$-galactosidase encoded by At5g56870 was identified as a secretory protein in culture medium of suspension cells by mass spectrometry analysis. This protein was specifically detected under sugar-starved condition with a specific antibody. Induction of these genes was repressed in suspension cells grown with galactose, xylose and glucose as well as with sucrose. In planta, expression of the genes and protein accumulation were detected when photosynthesis was inhibited. Glycosyl hydrolase activity against galactan also increased during sugar starvation. Further, contents of cell wall polysaccharides especially pectin and hemicellulose were markedly decreased associating with sugar starvation in detached leaves. The amount of monosaccharide in pectin and hemicellulose in detached leaves decreased in response to sugar starvation. These results supported my idea that cell wall has one of function to supply carbon source in addition to determination of cell shape and physical support of plant bodies.