• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.91-91
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• 2010

본 논문은 펄스 직류전원 (Pulse DC) 플라즈마 소스와 반응성 가스인 $CF_4$와 불활성 가스인 Ar를 혼합하여 산업에서 널리 사용되는 유기고분자인 Polymethylmethacrylate (PMMA), Polyethylene terephthalate (PET), 그리고 Polycarbonate (PC) 샘플을 건식 식각한 결과에 대한 것이다. 각각의 샘플은 감광제 도포 후에 자외선을 조사하는 포토레지스트 방법으로 마스크를 만들었다. 펄스 직류전원 플라즈마 시스템을 사용하면 다양한 변수를 줄 수 있다는 장점이 있다. 공정 변수는 Pulse DC Voltage는 300 - 500 V, Pulse DC reverse time $0.5{\sim}2.0\;{\mu}s$, Pulse DC Frequency 100~250 kHz 이었다. 변수 각각의 값이 높아질수록 고분자의 식각률이 높아졌다. 특히, PMMA의 식각률이 가장 높았으며 PET, PC 순이었다. 샘플 중 PC의 식각률이 가장 낮은 이유는 고분자 결합 중에 이중결합의 벤젠 고리 모양을 포함하고 있어 분자 결합력이 비교적 높기 때문으로 사료된다. 기계적 펌프만을 사용한 공정 전 압력은 30 mTorr이었다. 쓰로틀 밸브를 완전 개방한 상태에서 식각 공정 중 진공 압력은 $CF_4$ 가스유량이 늘어날수록 증가하였다. 식각률 역시 $CF_4$ 가스유량(총 가스 유량은 10 sccm)이 많을수록 증가함을 보여주었다 (PMMA: 10 sccm $CF_4$에서 330 nm/min, 3.5 sccm $CF_4$/6.5 sccm Ar에서 260 nm/min., PET: 10 sccm $CF_4$에서 260 nm/min, 3.5 sccm $CF_4$/6.5 sccm Ar에서 210 nm., PC: 10 sccm $CF_4$에서 230 nm, 3.5 sccm $CF_4c$/6.5 sccm Ar에서 160 nm). 이는 펄스 직류전원 플라즈마 식각에서 $CF_4$와 Ar의 가스 혼합비를 조절함으로서 고분자 소재의 식각률을 적절히 변화시킬 수 있다는 것을 의미한다. 표면 거칠기는 실험 후 표면단차 측정기와 전자 현미경 등을 이용하여 식각한 샘플의 표면을 측정하여 알 수 있었다. 실험전 기준 샘플 표면 거칠기는 PMMA는 1.53nm, PET는 3.1nm, PC는 1.54nm 이었다. 식각된 샘플들의 표면 거칠기는 PMMA는 3.59~10.59 nm, PET은 5.13~11.32 nm, PC는 1.52~3.14 nm 범위였다. 광학 발광 분석기 (Optical emission spectroscopy)를 이용하여 식각 공정 중 플라즈마 발광특성을 분석한 결과, 탄소 원자 픽 (424.662 nm)과 아르곤 원자 픽 (751.465 nm, 763.510 nm)의 픽의 존재를 확인하였다. 이 때 탄소 픽은 $CF_4$ 가스에서 발생하였을 것으로 추측한다. 본 발표를 통해 펄스 직류전원 $CF_4$/Ar의 고분자 식각 결과에 대해 보고할 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.501-510
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• 2016

Because hotels contain the cultural and artistic information of an era and plays a role as an iconic building to experience the unique regional culture, they are more than just a building. In recent years, as Jeju is emerging as a popular tourist city, a multi-functional and systematic plan for hotels is needed. Therefore, this study provides basic design data for hotel construction in the future by analyzing the public space of the luxury tourist hotels on Seogwipo-si. The public space of hotels, divided into service, food and beverage, banquet, leisure and convenience space, are categorized in terms of the cross combination type, entrance space form, plan type, unit space form to understand their relativity in the public space of hotels. This study reviewed the hotel construction based on the reference and literature, and, visited the sites to determine the current general status of hotels and then analyzed the architectural planning factors and spatial composition types.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.503-510
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• 2016

Even though children are exposed to the same amount of radiation, their effective dose amount is higher than those of adults. Therefore, it is very important to reduce the amount of unnecessary radiation exposure because children have a higher radiosensitivity and a smaller body size than adults. In this study, the proposal to seek ways to reduce the amount of radiation is drawn by comparing and analyzing CT Dose Index(CTDI) on the pediatric head CT which was performed at the Busan regional hospitals, to the national diagnostic reference levels. For this, the pediatric head CT scan was conducted among the CT equipments that were installed in downtown Busan. From 2,043 children 10 years old or less who were referred to the pediatric head CT scan, targeting the 28 CT equipments in the 24 hospitals that transmit dose reports to PACS, were examined retrospectively. As a result, the average value of CTDIvol, computed tomography dose index (CTDI) of infant brain, across the hospital, was 31.18 mGy, with DLP of $444.73mGy{\cdot}cm$, which exceeded the diagnostic reference level. The lower the age, the more management is needed for radiation. However, the reality is that the CT examinations are being conducted with a dose that exceeds the reference level as the age of the aged is exceeded. For this purpose, the study seeks to determine the degree of doses of doses outside the diagnostic reference level and analyze the cause of the excess dose and devise measures to reduce the dose reduction.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.497-510
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• 1992

This study was attempted to comparative investigate the types and regional distribution of the endocrine cells in several vertebrates immunohistochemically using seven antisera. From carp pancreas could be observed 4 types which are insulin-, glucagon-, som- and BPP-immunoreactive cells. Insulin-immunoreactive cells were mainly distributed at the periphery and a few cells occupied the central region of the islets. Glucagon-immunoreactive cells were distributed at the periphery of the islets, and som - and BPP-immunoreactive cells were located at the central region. From frog pancreas could be observed 4 types which are insulin-, glucagon-, som- and BPP-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the islets. Som-immunoreactive cells were distributed at the periphery of the islets, and glucagon- and BPP-immunoreactive cells were found as single cell or as small groups located between the pancreatic acini. From snake pancreas could be observed 3 types which are insulin-, glucagon- and som -immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the small islets, and they also were scattered at the periphery of the large islets. Glucagon-immunoreactive cells were distributed at the periphery of the islets, whereas som-immunoreactive cells were occupied the central region. From Ogolgae pancreas could be observed 4 types which are insulin-, glucagon-, som-and BPP-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the small islets, but at the periphery of the large one. Glucagon- immunoreactive cells were distributed at the periphery of the small islets and in the large islets showed scattering entired. Som-immunoreactive cells were distributed at the periphery of the small islets and in the large islets were located at the central region. A small numbers of BPP-immunoreactive cells were located at the periphery of the small islets and the exocrine regions. From the pancreas of the Korean native goat could be observed 6 types which are insulin-, glucagon-, som-, BPP-, 5-HT- and porcine-CG-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the islets. Som-immunoreactive cells were located at the periphery of the islets, but a tew were scattered at the central region of islets and in the epithelium of the secretory duct. Glucagon-, BPP-, 5-HT- and porcine CG-immunoreactive cells were distributed at the periphery of the islets. These findings indicated that the regional distribution patterns and cell types of pancreatic endocrine cells in vertebrates varies considerably among phylogenetically different vertebrates.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.504-510
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• 2015

This research was performed to evaluate soil contamination caused by copper depleted from ACQ-treated wood. Three years after the exposure of ACQ-treated wood in the field test sites, soil samples around the treated wood were collected and analyzed for the copper amount and distribution through soil. Soils around the deck posts installed in five different neighborhood parks located in Chonnam and Gyeongnam were investigated for copper contents. The results of the field test showed that the amount of copper leached from the end surface of treated wood buried under soil was more than 1.5 times the copper amount leached from the lateral surfaces, and the mobility of copper was very restricted in soil. The copper contents of soil within 10 cm from the treated deck posts installed in the parks showed to be less than 500 mg/kg, which are the limit values of the 2nd region set up by enforcement regulation of soil environment conservation act. The distribution ranges of copper in soil from the treated wood set up in the field test sites seemed to be much wider than those from deck posts, which may explained by the fact that the retentions of the treated samples used in the field test sites were much higher than those of the deck posts.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.510-521
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• 2001

Image retrieval system should be construct for searching fast, efficient image be extract the accurate feature information of image with more massive and more complex characteristics. Image retrieval system are essential differences between image databases and traditional databases. These differences lead to interesting new issues in searching of image, data modeling. So, cause us to consider new generation method of database, efficient retrieval method of image. In this paper, To extract feature information of edge using in searching from input image, we was performed to extract the edge by convolution Laplacian mask and input image, and we implemented the annotation-based and content-based image retrieval system for searching fast, efficient image by generation image database from extracting feature information of edge and metadata. We can improve the performance of the image contents retrieval, because the annotation-based and content-based image retrieval system is using image index which is made up of the content-based edge feature extract information represented in the low level of image and annotation-based edge feature information represented in the high level of image. As a conclusion, image retrieval system proposed in this paper is possible the accurate management of the accumulated information for the image contents and the information sharing and reuse of image because the proposed method do construct the image database by metadata.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.147-153
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• 2005

Naldrettite, recently discovered in the Mesamax Northwest deposit, Ungava region, northern Quebec, Canada, was reported as a new mineral. In order to confirm whether itis a natural equivalent of synthetic $Pd_2Sb$ phase or not, the pure $Pd_2Sb$ phase has been synthesized and investigated by reflected microscope, electron microprobe analyser, X-ray diffractometer, and micro-indentation hardness tester. Under reflected light synthetic $Pd_2Sb$ Phase is white with a creamy tint in both air and oil and weakly bireflectant. Anisotropism is strong, from brownish gray to greenish blue in air. Micro-indentation hardness test gives VHN100=293(242-322). Composition of the phase is $63.7\~64.3wt.\%\;Pd\;and\; 36.4\~36.8wt.\%$ Sb, and is entirely consistent. The phase, quenched from $500^{\circ}C$, is orthorhobic with space group $Cmc2_1$, and the cell parameters are a=3.366(1), b=17.523(3), c=6.929(2) ${\AA}$. All mineralogical properties of synthetic $Pd_2Sb$ compare very well with those of naldrettite, confirming that naldrettite is the natural analogue of the synthetic $Pd_2Sb$ phase.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.108-115
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• 2017

The purpose of this study was to investigate the influence of dental hygienist images and career advice among high school teachers. A self-reported questionnaire was administered to 212 high school teachers in Gwangju, South Korea. The questionnaire contained subject's general characteristics, images of dental hygienists, and career advice. We performed an independent t-test, the Kruskal-Wallis test, Pearson's correlation coefficient, multiple regression analysis, and logistic regression analysis using the IBM SPSS ver. 21.0 software. Using a five-point scale, the average of all the dental hygienist images was 3.50, with personal images receiving the most positive rating at 3.83 and social images receiving the least positive rating at 2.86. The images of dental hygienists were significantly more positive in instances where the subjects recognized the dental hygienist or received treatment within one year. There were positive correlations among different kinds of images. Through multiple regression analysis, occupational images were associated with business and social images. Business images were associated with occupational and personal images. Personal images were associated with business images, especially in cases where the subjects recognized the dental hygienist. Social images were associated with occupational images, especially in cases where subjects received treatment within one year. Through logistic regression analysis, career advice was associated with social and occupational images. Therefore, our study provides suggestions on how to enhance positive recognition of social images of dental hygienists.

• Journal of the Korean association of regional geographers
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• v.10 no.3
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• pp.497-510
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• 2004

This study searched for comparison with geography of Qing China, origin of geographical name, people's feature and costume, description on regional geography, and perception on locality on view of a geographer, Ji-Won Park, a renowned Korean scholar of practical learning on the late 18th century. This study on the first three chapters of his Yorha Ilgi - "Crossing the Amnok(Yalu) River("渡河錄")," "Several Records on Senyang("監京雜識")," and "Writing Essays, Riding Horses("馹迅隨筆")," focusing on landscape of Qing China, inquiry on geographical name, feature and costume, and descriptions on locality, gives a glimpse on Park's geographical view on geography of Qing China. His writing style to compare landscapes between Korea and Qing China, full of his love for Korean landscape, is very delicate and clear, Although he sentimentalized when he passed through Bonghwang-castle(鳳凰城) in China, his subtle and beautiful writing explains that land and mountains in Han-yang(Seoul) are much more wonderful than those in China. His vivid depiction of landscape and weather on his way in Qing China is remarkable and explanation on geographical names like Parhae(渤海), Yoha(遼河), Taejaha(太子河), Senyang(瀋陽) etc. is enough to stimulate readers' curiosity on geography.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.499-510
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• 2015

Artificial accelerated weathering test evaluated rocks from near the circuit road of Ulleungdo island, approximately 120 km from east of the Korean Peninsula. The tests subjected rock specimens to conditions based on the climate of the island. The specimens (such as basaltic breccia, trachyte, volcanic breccia) were preliminarily classified using a TAS diagram (XRF data) and based on the constituent minerals (XRD data); they were further classified by weathering degree according to their absorption ratios. During the artificial accelerated weathering, the absorption ratio of most of the specimens increased, but the point-load strength did not decrease in most cases, except for the volcanic breccia. The greater initial absorption ratio of trachyte rock specimen in comparison with the other specimens led to a greater increase of its absorption ratio during the artificial accelerated weathering test. The volcanic breccia specimens showed the greatest increase of absorption ratio and the biggest reduction ratio of the point- load strength during the tests. These results could aid prediction of the weathering rate of rocks in Ulleungdo island subjected to weathering processes; trachyte which appears to accelerate with time, and volcanic breccia whose mechanical strength can largely decrease in a relative short period of time. Proper measures therefore appear necessary for the prevention of natural disaster such as rock fall and landslide around the circuit road.