• Composites Research
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• v.28 no.3
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• pp.104-111
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• 2015

In this work, a structural design on 500W class horizontal axis wind turbine blade using natural-fibre composite is performed. The structural design result of flax composite blade is compared with the result of glass composite blade. The structural design of the wind turbine blade is carried out using the simplified methods such as the netting rule and the rule of mixture. The structural safety of the designed blade structure is investigated through the various load cases, stress, deformation and buckling analyses using the commercial FEM. The structural test of the manufactured prototype blade was performed to confirm the structural analysis results including strains, natural frequencies and deformations. According to the comparison results, it was confirmed that the analysis results are well agreed with the experimental results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.11-16
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• 1972

During the period from 1966 to 1968, total catches of Spanish mackerel averaged 6,000 to 7,000M/T per annual in Korea, and approximately 70 per cent of this amount was captured by drift nets. In an effort to improve the efficiency of drift nets, some experiments were conducted in 1969 to investigate the selectivity of material and mesh sizes. Seven different mesh sizes (80,85,95,100,105,110 and 115 mm) of both multi- and mono-filament netting were used, and the following results were obtained : 1, The body weight of Spanish mackerel taken with the seven different mesh sizes ranges from 0.5kg to 2.9kg, and the mode of body weight consists of three groups, 1kg ($21%$), 1.3kg($15\%$) and 1.5kg($19\%$). 2. For multi-filament net, 80 to 105mm mesh sizes were suitable to catch those three groups, and a little smalter than these for mono-filament net. 3. For Spanish mackerel only, the mono-filament material proved to have 1.5 times better selectivity than multi-filament : however, the latter proved superior for miscellaneous fish species due to its different size and shape. 4. Multi-filament net showed better selectivity for smaller species than mono-filament. (and mono-filament in general indicated opposite phenomenon.)

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.171-183
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• 1992

In this paper, the behaviour of cavitation erosion, influence of corrosion and corrosion control on slide bearing metals for internal combustion engine were investigated, and this experiment was done by the vibratory cavitation erosion tester. The main results obtained are as follows: 1. With decreasing the space between horn and specimen, the weight loss and its rate increased step by step. But the weight loss and its rate of 0.2mm space decreased conversely more than that of 0.4mm space at early stage. 2. The weight loss and its rate with change of pH were appeared to the order of pH2>pH12>pH7>pH4. And the weight loss and its rate at pH 4 decreased at best. 3. The weight loss and its rate by cavitation erosion for bearing metals were shown to the order of W.M7>W.M1>K.M4. 4. There appeared mainly small pit hole at pH2, and appeared the pit of netting thread type at pH12 by the results of the damaged surfaces at pH2 and pH12 environments that were sensitive to cavitation erosion. 5. With increasing the viscosity of lubricating oil, the weight loss rate by cavitation erosion became dull at the space below 0.5mm. 6. The protective efficiency of cavitation erosion-corrosion is superior inhibitor of chormate(25 ppm) to cathodic protection.

• Fashion & Textile Research Journal
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• v.13 no.5
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• pp.672-678
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• 2011

This was written based on the type and structure of korean man's waist belt in the early and middle era of the Chosun era. The waist belt was excavated from the Mokdaldong in the Daejeon city. The types of korean man's waist belt in the Chosun era were classified into Wondahae (i.e., round shape belt) and Gwangdahae. The Wondahae consist of two types which are circle shaped and straight types. The circle shaped wondahae contain one fringe in the main body of the belt and its joint part is decorated with a small network such as lacing decoration with the size about 1 cm around. The shape of the Wondahae has been changed from the circle shaped into the straight types and also has a tendency to be wider and longer as time went by. The standard form of the Gwangdahae is straight with about 2-3 cm width and elaborated by lacelike fringe as well. This also has a tendency to be wider starting from the 1600s show. The structure of this belts were divided into braid and ornament parts. The ornament part was constructed with the lacelike netting and fringe parts. The sophisticated craft techniques have a great decorative beauty. Through an analysis of FT-IR, the materials of those three belt are known which are made of the silk and the core thread was filled with cotton. Moreover, it can be confirmed that the glitter material of the ornament part were designed with gold foil and has been analyzed with SEM-EDX.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.563-567
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• 2002

Developing base data on luring fish schools into netting position by the use of underwater audible sound on japanese parrot fish Oplegnathus fasciatus found in the coastal waters of Jeju Island, S. Korea. Auditory threshold was determined by the heartbeat condition technique using pure tones coupled with a delayed electric shock. The audible range of japanese parrot fish extended from 80 Hz to 500 Hz with a peak sensitivity at 200 Hz. The mean auditory thresholds at the frequencies of 80 Hz, 100 Hz, 200 Hz,300 Hz and 500 Hz were 104 dB, 95 dB, 91 dB, 99 dB and 113 dB, respectively. As the frequency became higher than 200 Hz, the auditory threshold increased almost linearly with increasing frequency. Critical ratios of fishes measured in the presence of masking noise in the spectrum level range of 69$\~$78 dB (0 dB re 1$\mu$Pa/$\sqrt{Hz}$) ranged from 21 dB to 40 dB at test frequencies. The noise spectrum level at the start of masking was about 70 dB within the test frequency range. The sound pressure level of 100$\~$200 Hz recognized by japanese parrot fish under the ambient noise is above 91 dB and the critical ratio for them is above 21 dB.

• Parasites, Hosts and Diseases
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• v.52 no.4
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• pp.399-412
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• 2014

The infection status of zoonotic trematode metacercariae was investigated in a total of 2,293 freshwater fish collected from 11 rivers or streams in 9 administrative regions of Gangwon-do, Korea for 5 years (2009-2013). All fish were collected by netting methods and examined using the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 4 fish species, i.e., Pungtungia herzi, Squalidus japonicus coreanus, Acheilognathus rhombeus, and Ladislabia taczanowskii, from only Hantangang in Cheorwon-gun. Metagonimus spp. metacercariae were found in 1,154 (50.3%) fish and their average number per infected fish was 55.8. Among the positive fish species, especially Tribolodon hakonensis from Namdaecheon in Yangyang-gun and Plecoglossus altivelis from Osipcheon in Samcheok-si were most heavily infected. Centrocestus armatus metacercariae were detected in 611 (26.7%) fish and the average metacercarial burden per infected fish was 1,032. Two chub species, Zacco platypus and Zacco temminckii were highly and heavily infected with C. armatus metacercariae in almost all regions surveyed. Echinostoma spp. metacercariae were also found in 24 fish from a few localities, but their numbers per fish infected were very low. From the above results, it is confirmed that the metacercariae of intestinal flukes, especially Metagonimus spp. and C. armatus, were heavily infected, while C. sinensis metacercariae were rarely found in fish from Gangwon-do, Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.1
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• pp.60-65
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• 2000

The virtual mass of net is an important parameter in the analysis and control of net movement in the water. This experiment was performed with the purpose of getting a relation on the quantity of netting and virtual mass of trawl nets using the circulating water channel that can control flow speed. Twelve types of conical nets were examined. Resistance of the conical net at the steady and acceleration state was recorded as text on the personal computer through the tension meter and current meter. The results were obtained as follows ;1. Resistance(R) of the conical net is proportional to the degree of attack angle in the sam e amount of twine material.2. Coefficient of the resistance(Cd)could be defined by the following regression model as a function of Reynolds Number(Re). Cd=0.039Re-0.14743. Resistance(R) is proportional to TSA(Twine surface area) and defined as follows; R=21.398TSA-0.12194. Coefficient of virtual mass(CM) could be calculated by the following first order regression model. CM=37.557U-8.96845. Virtual mass is directly proportional to Volume of net(V) or d/l.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.336-343
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• 2014

Modern advanced-turboprop propellers are required to have high structural strength to cope with the thrust requirement at high speed. The high stiffness and strength carbon/epoxy composite material is used for the major structure and skin-spar-foam sandwich structural type is adopted for advantage in terms of the blade weight. As a design procedure for the present study, the structural design load is estimated through investigation on aerodynamic load and then flanges of spars from major bending loads and the skin from shear loads are sized using the netting rule and Rule of Mixture. In order to investigate the structural safety and stability, stress analysis is performed by finite element analysis code MSC. NASTRAN. It is found that current methodology of composite structure design is a valid method through the static structural test of prototype blade.

• Journal of the Korea Fashion and Costume Design Association
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• v.16 no.4
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• pp.117-136
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• 2014

The purpose of this study is to present a classification system of the hand-made and machine-made lace according to the configuration method and re-make the category and definition of lace to consider the emergence and development of major laces techniques. The re-made category and definition of the lace is as follows. The lace usually consists of ground and motifs, however, the techniques of netting and sprang are suitable for making ground than motif, so I think it is appropriate to exclude them from the category of the lace. Many scholars are excluded openwork embroidery fabric from the category of the lace. But, an openwork embroidery fabric is the basis of a needle point lace called true lace and is consist of motif and ground. I think it is appropriate to include it in the category of the lace. I think it is also appropriate to include in the category of the lace that the eyelet embroidery fabric which mimics the openwork embroidery fabric in the machine. Lace is redefined that a fabric with openwork decoration consists of motif and ground, constructed by a variety of ways such as plaiting, twisting, looping, knotting of threads or embroidering by hand or machine. The classification of the lace is presented as follows. Hand-made lace is classified bobbin lace, needle point lace, embroidery lace, knotted lace, crochet lace, and knitting lace. Machine-made lace is classified raschel lace, leaver lace, torchon lace, and machine-made embroidery laces which include tool lace, eyelet embroidery lace, chemical lace, etc.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.93-104
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• 2012

In this research LCA methodology was adapted and analyzed in quantifying estimation of estuarine environment. The analysed objects of estuarine environment were construction methods, facility, and input material into water, and estuarine ecosystem. In this research the function of LCA of estuarine environment was river with the view of controling water, utilizing water, and hydrophilic function. According to the result of research, environmental damage indicator of facility was decreased 346 Pt from 453 Pt at pre-maintenance to 107 pt at post-maintenance. Among raw and subsidiary materials, remicon, stone-netting bag, and pebbles were showing heavy environmental load in the order. Evironmental impact of input material into water system was analyzed from 1,827 Pt environmental load before construction to 1,080 Pt of post-maintenance, and damage indicator was improved at 747 Pt. Water quality was improved from 1,827 Pt (before construction) to 1,080 Pt(after construction), and ecosystem was improved after maintenance. Environmental indicator in ecosystem was analyzed 427 Pt(before construction) to 348 Pt(after construction), and damage indicator of Sumnjingang riverine system was improved as much as 79 Pt. In the conclusion, estuarine environmental monitoring through LCA in the area of facility, input material into water and ecosystem showed that close-to-nature stream was 1,172 Pt better than artificial stream in environmental aspects.