• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권3호
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• pp.235-240
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• 2006

Solitary plasmacytoma is a rare malignant neoplasm that originate in immunoglobulin-producing plasma cell. Solitary bone plasmacytoma can be found at any site throughout the skeleton and in most cases eventually progresses to multiple myeloma, of which it is thought to be an unusual presentation. On the other hand, extramedullary plasmacytoma has a tendency to occur in the head and neck region, mainly in association with the upper air passages. Incisional biopsy is the primary approach to make a definitive diagnosis, and immunohistochemical staining can be very helpful in understanding the nature of these tumors. We report a 66 years old patient with solitary bone plasmacytoma and a 36 years old patient with solitary extramedullary plasmacytoma with literatures review.

• 한국결정학회지
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• 제3권1호
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• pp.1-8
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• 1992

졸겔 및 공침법으로 제조된 티탄산 납 분말의 형태를 하소온도와 하소시간의 함수로 조사하였다. 질산 납과 사염화 티탄의 혼합용액을 사용하여 40-43℃ 및 9.0-9.7 pH에서 PbTiO3 전구체를 제조하였으며, 350-1000℃에서 1-10시간동안 공기중에서 이들을 히소시켰다. 하소온도와 시간의 증가에 따라 입자의 크기가 증가하고 응집이 심화되었다. 졸겔법으로 제조된 분말을 700℃에서 히소시킬 때, 초기에 형성된 침상형 혹은 각주 형의 입자들은 하소가 진행됨에 따라 다면체형으로 변한뒤, 모서리가 둥근 다면체형 입자로 성장하였다. 공침법으로 제조된 분말은 결정화 과정중에 형태가 변화되지 않았다.

• 한국안전학회지
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• 제30권3호
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• pp.7-12
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• 2015

CFRP composites are used as primary structural members in various industrial fields because their specific strength and specific stiffness are excellent in comparison to conventional metals. Their usage is expanding to high added-value industrial fields because they are more than 50% lighter than metals, and have excellent heat resistance and wear resistance. However, when CFRP composites suffer impact damage, destruction of fiber and interface delamination occur. This causes an unexpected deterioration of strength, and for this reason it is very difficult to ensure the reliability of the excellent mechanical properties. Therefore, for the destruction mechanism in bending with impact damage, this study investigated the reinforcement data regarding various external loads by identifying the consequential strength deterioration. Specimens were damaged by impact with a steel ball propelled by air pressure. Decrease in bending strength caused by the tension and compression of the impact side, and depending on the lamination direction of fiber and interface inside the specimen. From the bending test it was found that the bending strength reduced when the impact energy increased. Especially in the case of compression on the impact side, as tensile stress occurred at the damage starting point, causing rapid failure and a substantially reduced failure strength.

• 한국대기환경학회지
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• 제29권6호
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• pp.722-733
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• 2013

Ground-based measurements were conducted from August 25 to September 8 of 2011 for understanding characteristics of carbonaceous aerosols measured at Gosan. Chemical components and their sources were discussed by analysis of organic compounds with identification of primary and secondary products in particulate matter. Thus, organic carbon (OC) and elemental carbon (EC) based on the carbonaceous thermal distribution (CTD), which provides detailed carbon signature characteristics relative to analytical temperature, was used to improve the carbon fractionation of the analytical method. In addition, organic compounds by gas chromatography technique with the backward trajectories were discussed for characteristics of carbonaceous aerosols. Different air-masses were classified related to the OC thermal signatures and the organic molecular markers such as aromatic acids and PAHs. We concluded that the aging process was influenced by the long-range transport from East Sea area.

• 한국항공운항학회지
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• 제18권3호
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• pp.55-69
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• 2010

The role of airports in the metropolitan area in Korea is very important which is located on the center of Northeast Asia considered as the highest potential growth continent in the world air transport market. This study includes comparison on service quality between Gimpo Airport and Incheon Airport which are indicated as multi-airport system in the metropolitan area appraised by passengers from Korea, Japan and China, and analysis on primary factors of airport service which affect the customer satisfaction and loyalty. The service quality appraised in the order of Chinese, Korean, and Japanese and the analysis result indicated that the service quality factors which influence on customer satisfaction and loyalty were all different among passengers from three countries. Information service was the priority factor for customer satisfaction to Chinese and Korean, but Japanese considered that personal service was the most important factor. This research paper tried to provide many current issues and guides to operational strategy including plan for the specialized routes of multi-airport system in domestic metropolitan area.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.64-71
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• 2005

효과적인 초음속 연소를 위해 연료와 공기의 빠른 혼합이 필요하며, 혼합 향상을 위해 연료분사 방식에 대한 여러 연구들이 수행되어 왔다. 본 연구에서는 길이-깊이 비가 4.8, 후면 경사각이 $22.5^{\circ}$인 개방형 공동 모델을 사용하였으며, 마하수 1.92에서 운동량비에 따른 분사구 주변의 유동 특성 및 연소실 내 압력 분포를 슐리렌 가시화와 압력 측정을 사용하여 파악하였다. 운동량비는 연료의 침투거리와 분사지역의 유동에 큰 영향을 끼친다.

• 한국분말재료학회지
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• 제9권3호
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• pp.167-173
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• 2002

A new approach to produce nanostructured WC/Co composite powders by a mechanochemical process was made to improve the mechanical properties of advanced hardmetals. Homogeneous spherical W-Co salt powders were made by spray drying of aqueous solution from ammonium metatungstate($(NH_4)_6(H_2W_{12}O_{40})\cdo4H_2O$,AMT) and cobalt nitrate hexahydrate (Co(NO$_3$)$_2$.6$H_2O$). spray dried W-Co salt powders were calcined for 1 hr at $700^{\circ}C$ in atmosphere of air. The oxide powder was mixed with carbon black by ball milling and this mixture was heated with various temperatures and times in $H_2$. The $WO_3/CoWO_4$ composite oxide powders were obtained by calcinations at $700^{\circ}C$. The primary particle size of W/Co composite oxide powders by SEM was 100 nm. The reduction/carburization time decreased with increasing temperatures and carbon additions. The average size of WC particle carburized at $800^{\circ}C$ by TEM was smaller than 50 nm.

• 한국대기환경학회지
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• 제27권3호
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• pp.255-271
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• 2011

ACE-Asia (Asian Pacific Regional Aerosol Characterization Experiment) in spring 2001 was a turning point to trigger international research interest on Asian dust (AD). This basically arose from the lack of research on AD, the important natural phenomenon to characterize the Northeast Asia. In contrast, health risk related to AD has been the primary concern in Korea. Although due in part to severe AD events of 2001~2002, research and mitigation measures on AD in Korea are typically based on the assumption that AD events are increasing in frequency and severity. However, contrary to the trend in Korea, the number of AD days and emission amounts of AD in China have decreased since 1980s. This paper reviews the impacts of AD on ambient air quality and variations in toxic substances during the AD event, reflecting the concern in Korea. While a great amount of dust particles flow into Korea during the AD event, a considerable amount of dust particles are locally generated as well. Since dust particles are mixed with toxic substances as they pass over polluted areas, the levels of toxic substances become lower in dust particles that do not pass over polluted areas. Broadening the research scope on AD is warranted to understand the AD as an important natural phenomenon, irrespective of its associated health risk.

• Environmental Analysis Health and Toxicology
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• 제19권2호
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• pp.161-167
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• 2004

Air quality monitoring is a primary activity for industrial and social environment. The government identifies the pollutants that each industry must monitor. Especially, the VOCs (Volatile Organic Compounds), which are very harmful to human body and environment atmosphere, should be controlled under the government policy. However, the VOCs, which have not been confirmed in emission sources are very difficult to monitor. It is needed to develop the monitoring system that allow the continuous and in situ measurement of VOCs mixture in different environmental matrices. Gas chromatography and mass spectrometry are the most prevalent current techniques among those available for the analysis of VOCs. But, they need a large size analytical instrument, which costs a great deal for purchase and operation. In addition, it has some limitations for realtime environmental monitoring such as location problems and slow processing time. Recently, several companies have commercialized a portable VOCs measurement systems, which cannot classify various kinds of VOCs but total quantities. We have developed a VOCs measurement system, which recognizes various kinds and quantities of VOCs, such as benzene, toluene, and xylene (BTX). Also, it can be used as a stand- alone type and/or fixed type in the vehicle with rack for real -time environmental monitoring.

• KIEAE Journal
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• 제10권4호
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• pp.45-50
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• 2010

This study for middle school facilities is second following the study of the energy consumption of primary school facilities. There is not on the analysis of the current energy usage for middle school facilities in nations to set goals of energy reduction. Therefore, The purpose of this study is to present various analysis result of energy consumption which is a statistical analysis of domestic middle school facilities in South Korea. As a consequence, each average energy consumption at the domestic middle school facilities analyzed as following after changing as unit 'kWh' only for comparison with every energy source. It represents that the energy consumption of electric power was 183.7MWh(70.2%), gas consumption for heating was 46.5MWh(17.8%), oil consumption was 26.5MWh(10.1%), district energy was 5.1MWh(1.9%). This result describes that consumption of electric power was large greatly and it reflects the expectation that it will climb the demand regarding this energy in the future. In additionally, it analyzed average energy consumption with $74.4kWh/m^2$ by the unit area of air-conditioning and the district which has large energy consumption was Seoul with $91.6kWh/m^2$.