• 수산경영론집
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• 제51권2호
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• pp.71-87
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• 2020

Oysters are the most abundantly harvested type of shellfish in Korea. As export of this marine product increases, oysters have greatly contributed to an increase in fishing income. As the oyster aquaculture industry has rapidly grown since the late 1990s, issues of oyster-shell processing that occur in production processes have re-emerged as important topics in the oyster industry. The amount of oyster shells harvested in 2019 is estimated to be approximately 300,000 tons. With reductions in demand for pyrolytic fertilizer and feed, which are currently the greatest sources of demand, unprocessed shell quantities have doubled compared to 2018, causing them to be an issue once more. Such oyster-shell processing also incurs great costs, and a total of forty-six billion three hundred fifty million Korean won (46,350,000,000 KRW) has been provided from 2009 to 2020 for the use of oyster shells as a resource. According to current Korean laws, oyster shells are considered to be industrial waste if more than 300 kilograms are sent out in a day. Collection and processing must be conducted by a waste-consignment company. Consequently, there are many limitations to the use of oyster shells in Korea as a resource. However, in Japan, only oyster-shell waste is regulated by waste-processing As a result, local governments may apply exceptions when utilized as organic matter. Consequently, in Japan, oyster shells are being used as resources in more diverse fields than in Korea. This study observes the conditions and problems of oyster-shell processing in Korea and attempts to find new domestic oyster-shell resource solutions in light of Japan's recycling practices.

• Geomechanics and Engineering
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• 제22권3호
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• pp.227-236
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• 2020

Expansive soils are renowned for their swelling-shrinkage property and these volumetric changes resultantly cause huge damage to civil infrastructures. Likewise, subgrades consisting of expansive soils instigate serviceability failures in pavements across various regions of Pakistan and worldwide. This study presents the use of polypropylene fibers to improve the engineering properties of a local swelling soil. The moisture-density relationship, unconfined compressive strength (UCS) and elastic modulus (E₅₀), California bearing ratio (CBR) and one-dimensional consolidation behavior of the soil treated with 0, 0.2, 0.4, 0.6 and 0.8% fibers have been investigated in this study. It is found that the maximum dry density of reinforced soil slightly decreased by 2.8% due to replacement of heavier soil particles by light-weight fibers and the optimum moisture content remained almost unaffected due to non-absorbent nature of the fibers. A significant improvement has been observed in UCS (an increase of 279%), E₅₀ (an increase of 113.6%) and CBR value (an increase of 94.4% under unsoaked and an increase of 55.6% under soaked conditions) of the soil reinforced with 0.4% fibers, thereby providing a better quality subgrade for the construction of pavements on such soils. Free swell and swell pressure of the soil also significantly reduced (94.4% and 87.9%, respectively) with the addition of 0.8% fibers and eventually converting the medium swelling soil to a low swelling class. Similarly, the compression and rebound indices also reduced by 69.9% and 88%, respectively with fiber inclusion of 0.8%. From the experimental evaluations, it emerges that polypropylene fiber has great potential as a low cost and sustainable stabilizing material for widespread swelling soils.

• 지역연구
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• 제31권3호
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• pp.55-77
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• 2015

이 연구의 목적은 수도권 시군구별 입지요인이 제조업 기업들의 생애주기에 미치는 영향을 실증분석 하는 것이다. 한 기업도 가구와 마찬가지로 일련의 생애주기를 갖는다. 기업의 생애주기를 선행연구에서는 기업통계(firmography)로 정의하고 있으며, 이를 생성, 성장, 쇠퇴, 소멸의 단계로 구분하였다. 이 연구에서도 기업의 생애주기 단계를 동일하게 적용하였으며, 제조업 기업들을 대상으로 경공업과 중공업, 첨단제조업으로 구분하여 분석하였다. 수도권 시군구별 입지요인은 도시규모와 교통접근성, 사회 경제특성, 수도권 권역구분으로 구분하여 총 12개의 입지요인을 독립변수로 적용하였다. 분석결과, 경공업과 중공업, 첨단제조업 기업별로 기업의 생애주기에 미치는 유의미한 입지요인이 차이가 있었으며, 입지계수 또한 각각 다르게 나타났다. 이 연구결과는 기업유치를 통해 일자리를 늘리려는 지자체에서 신규기업의 생성뿐만 아니라 기존 기업의 성장을 도모하는 정책을 수립하는데 있어서 중요한 기초자료가 될 수 있을 것으로 기대된다.

• Journal of Ecology and Environment
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• 제42권3호
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• pp.103-110
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• 2018

Backgrounds: In arid grasslands, wells are subject to heavy trampling and grazing pressure, which can increase vulnerability to local land degradation. To investigate trampling and grazing, we surveyed plant communities at three well sites in the desert steppe of Mongolia, using 1600-m line transects from the wells. The sites (Bshrub, Sshrub, and shrubL) differed by concomitant shrub type (big shrub, small shrub, and shrub-limited) and livestock pressure (light, medium, and heavy). A plant classification scheme based on edibility and morphology (rosette or creeping type) was used to separate grazing and trampling effects on plant communities. Results: Edible plants were dominant at all sites but a fraction of grazing- and trampling-tolerant plants increased in the order Bshrub, Sshrub, and shrubL, following livestock pressure. Clear transition zones from inedible to edible plant groups were recognized but at different locations and ranges among the sites. Trampling-tolerant plants explained 90% of inedible plants at Sshrub with camels and horses, but grazing-tolerant plants prevailed (60%) at shrubL with the largest livestock number. Plant coverage increased significantly along the transects at Bshrub and Sshrub but showed no meaningful change at shrubL. Herbaceous plant biomass showed significant positive and negative trends at Bshrub and shrubL, respectively. Conclusions: Both grazing and trampling can produce larger fractions of inedible plants; in this, camel and horses can have considerable effects on desert-steppe plant communities through trampling.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.76.1-76.1
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• 2015

Optical resonances of metallic or dielectric nanoantennas enable to effectively convert free-propagating electromagnetic waves to localized electromagnetic fields and vice versa. Plasmonic resonances of metal nanoantennas extremely modify the local density of optical states beyond the optical diffraction limit and thus facilitate highly-efficient light-emitting, nonlinear signal conversion, photovoltaics, and optical trapping. The leaky-mode resonances, or termed Mie resonances, allow dielectric nanoantennas to have a compact size even less than the wavelength scale. The dielectric nanoantennas exhibiting low optical losses and supporting both electric and magnetic resonances provide an alternative to their metallic counterparts. To extend the utility of metal and dielectric nanoantennas in further applications, e.g. metasurfaces and metamaterials, it is required to understand and engineer their scattering characteristics. At first, we characterize resonant plasmonic antenna radiations of a single-crystalline Ag nanowire over a wide spectral range from visible to near infrared regions. Dark-field optical microscope and direct far-field scanning measurements successfully identify the FP resonances and mode matching conditions of the antenna radiation, and reveal the mutual relation between the SPP dispersion and the far-field antenna radiation. Secondly, we perform a systematical study on resonant scattering properties of high-refractive-index dielectric nanoantennas. In this research, we examined Si nanoblock and electron-beam induced deposition (EBID) carbonaceous nanorod structures. Scattering spectra of the transverse-electric (TE) and transverse-magnetic (TM) leaky-mode resonances are measured by dark-field microscope spectroscopy. The leaky-mode resonances result a large scattering cross section approaching the theoretical single-channel scattering limit, and their wide tuning ranges enable vivid structural color generation over the full visible spectrum range from blue to green, yellow, and red. In particular, the lowest-order TM01 mode overcomes the diffraction limit. The finite-difference time-domain method and modal dispersion model successfully reproduce the experimental results.

• Journal of Nutrition and Health
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• 제38권2호
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• pp.125-143
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• 2005

The purposes of this study were to investigate the characteristics of lifestyle and dietary habits of the colorectal cancer patients in Daegu and Kyungpook areas and to collect the data useful for nutrition education for the prevention of colorectal cancer in this community. The case subjects of the study were 123 patients diagnosed recently as colorectal cancer at Kyungpook National University Hospital. The control subjects were 182 persons who did not have any gastrointestinal diseases, including the patients from the department of orthopedic surgery and healthy volunteers. The survey covering general characteristics, life style, dietary habits, eating behaviors, and food intake frequency was administered by individual interviews using questionnaires. The results of the study suggest that high BMI, daily life stress, pessimistic personality, lack of physical activities, and familial cancer history might be the possible risk factors for the incidence of colorectal cancer. Dietary factors suspected as risk factors for colorectal cancer in the present study included strong preferences to meats, salty and fatty taste foods, low intake of water, alcohol drinking, smoking, coffee intake and irregular eating habits. A high consumption of seaweeds, green-yellow vegetables, light-colored vegetables, and green tea was suggested as a preventive factor for colorectal cancer. It is recommended to conduct more extensive and systematic surveys in the near future to reconfirm the risk factors of colorectal cancer in consideration of the characteristic food culture in this community. The results of the present study may be applied to nutritional education for the prevention of colorectal cancer for the local residents. (Korean J Nutrition 38(2): 125～143, 2005)

• 조명전기설비학회논문지
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• 제15권6호
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• pp.8-14
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• 2001

메탈핼라이드램프는 고효율, 고연색성이며 집광능력이 좋다. 그러나 메탈핼라이드 램프의 단점은 아크튜브내에서 음향공명현상이 발생되는 것으로 알려져 있다. 이러한 음향공명은 점등상태의 불안정과 기체의 심한 파동을 일으킨다. 심한 파동과 불안정한 점등으로 아크가 소멸되는 부위는 전압이 상승되고, 방전관내벽에 근접된 아크는 국부의 과열로 튜브를 금가게한다. 이 연구의 목적은 펄스스타트 메탈핼라이드램프 MH200[W]의 아크튜브내에서 음향공명을 감소시키는 것이다. 음향공명현상을 감소시키기 위하여 전자식안정기가 84.6[kHz]에서 94.2[kHz] 대역내에 있는 89[kHz]의 단독주파수인 정현고주파를 램프에 공급하기 위하여 설계되었다. 실험결과 고효율 펄스스타트 MH200[W] 램프의 방전관내에 음향공명 현상이 없었다.

• Journal of Periodontal and Implant Science
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• 제33권4호
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• pp.573-584
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• 2003

Bone remodeling results from the combined process of bone resorption and new bone formation which is regulated in part by some of Dexamethasone related proliferation & mineralization of cultured bone cell and polypeptide growth factors such as platelet derived growth factor(PDGF), which has been known to be an important local regulator of bone cell activity and participate in normal bone remodeling. To evaluate the effects of Dex and PDGF on bony healing of calvarial defect in rats, 10 ng/ml PDGF were applied on P group and 10 ng/ml PDGF and $10^7$ M Dex were applied PD group. 4 rats in each group were sacrificed at 7, 14. 21 days after operation respectively, and the tissue blocks were prepared for light microscope with H-E for evaluation of overall healing, with TRAP(tartrate resistant acid phosphatase) for evaluation of osteoclastic activity and with immunohistochemical staining for macrophages. The results were as follows : 1. In all group, healing aspects were progressed from 7 days to 21 days in soft and bony tissue, but complete repair were not observed in bony defect 2. PDGF and control group were showed similar bony healing aspect , but bony healing in combination of PDGF-BB and Dex were observed slower aspect compared to PDGF and control group from early healing times. 3. There were no significant difference on activities of osteoclast and macrophages in bony healing between control and experimental group In conclusion, PDGF were not influenced on bony healing of defect and combination of PDGF-BB and Dex were showed slower healing through early healing times. it was considered that Dex compared to PDGF did influenced on early hone formation factors in healing period

• 한국기계가공학회지
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• 제17권2호
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• pp.89-94
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• 2018

Due to industrial advancement and environmental concerns, there is a demand for light-weight material parts with high-performance characteristics. In order to meet this demand, various studies have been conducted on developing high-performance castings to achieve composite features by coating only specific parts that require high performance, with dissimilar joining, rather than coating the entire material part. This study analyzed the possibility of forming a local composite layer on an aluminum alloy through evaporation pattern casting, and the effects of parameters on the aluminum alloy.

• 한국의사학회지
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• 제24권1호
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• pp.57-62
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• 2011

With the discovery of WooJam JabJeo, Jang-Taegyung[1809~1887] was highlighted as a noted doctor who won fame in the neighborhood of Gwangju, but with 'WoodJam Mango' seeing the light of day, this study was able to confirm the appearance of a literary man enjoying a reputation enough to sway literary circles with his writing of poems. It's possible to confirm his past related to medical service only until age of 42, which is because description in "WooJam JabJeo" came to a halt there. The situation is that the contents of 'WooJam Mango' started from age of 46 and were carried on even until after his death by his followers. Therefore, there exists a very intense impression that he might have put a focus on the life as a literary man ever after his mid-40s. and considering that he breathed his last at the age of 79, it's not difficult for us to estimate that his life was predominantly a series of literary activities rather than a health care provider. The place names appearing in "WooJam JabJeo" and "WooJam Mango" are limited to today's Jeonlanam-do, and this researcher would say that the through-composed poems, which sang of the beauty of Gwangju area scenery are the works, deserve to get a spotlight in local history even today. Through the above discussion, this study could prove that WooJam is a flawless figure enough to represent Gwangju and Jeonlanam-do as a health care provider and a literary person as well.