• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.5
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• pp.378-384
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• 1990

A neritic copepod previously known as Acartia clausi Giesbrecht in the Korean waters was taxonomically re-examined, and the species has been identified as Acartia omorii and Acartia hudsonica. These species are easily discriminated by the morphology of the 3rd segment of the 5th right leg in male and by the shape of the genital segment in female. A. omorii occurs along the coast of Korea, and A. hudsonica is restricted to the brackish waters of Pusan area.

• Atmosphere
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• v.26 no.2
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• pp.289-299
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• 2016

Optical properties of aerosols associated with haze events over Seoul were examined using ground-based skyradiometer and satellite-borne CALIOP and MODIS measurements over the 2009~2010 period. It is shown that aerosol optical thickness (AOT), ${\AA}ngstr{\ddot{o}}m$ exponents (${\alpha}$), and fine-mode particles increase during the haze events. The CALIOP-measured vertical profiles of aerosol during the haze events revealed that most of aerosols are loaded within layers below 4 km altitude. A large portion of these events appear to be related to the long-range transport of aerosols from China; about 35% and 18% of the haze events observed over Seoul were traced back to northern China and southern China, respectively. Compared with optical properties for locally-induced haze events (25%), these long-range transported aerosols are found to have relatively higher AOTs.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.405-410
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• 2009

This paper presents a case study that achieved both of serviceability and safety of the building through soil reinforcement and restoration around foundations subjected to serious differential settlement using D-ROG method. The building which has one basement floor and three ground floors is founded on soft ground and differential settlement occurred to the maximum extent of 678mm. The foundation type of the building is a independent mat foundation. Soil profiles consist of landfill layer, alluvial layer, weathered rock, and soft rock. The bearing layer consisting of gravel and weathered rock is located 16.0~17.0m below the bottom of the building. As a result of soil reinforcement and restoration, the recovery ratio of more than 90% can be attained with the maximum set-up of 657mm.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.571-578
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• 2009

Recently, micropiling techniques are increasingly applied in foundation rehabilitation/underpinning and seismic retrofitting projects where working space provides the limited access for conventional piling methods. Micropiling techniques provide environmental-friendly methods for minimizing disturbance to adjacent structures, ground, and the environment. Its installation is possible in restrictive area and general ground conditions. The cardinal features that the installation procedures cause minimal vibration and noise and require very low ceiling height make the micropiling methods to be commonly used for underpin existing structures. In the design point of view, the current practice obligates the bearing capacity of micropile to be obtained from skin friction of only rock-socketing area, in which it implies the frictional resistance of upper soil layer is ignored in the design process. In this paper, a new micropiling method and its verification studies via field installation are presented. The new method provides a specific way to grout bore-hole to increase frictional resistance between surrounding soil and pile-structure and it allows to consider the skin friction of micropiles for upper soil layer during design process.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.123-131
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• 2005

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of the anchors used in foundation system of underground structures which are applied to uplifting seepage forces. Small scaled pull-out tests in sand under saturated condition and dry condition were carried out. For estimating the group effects of the anchors, the upward displacement and the pullout load varied with spacing of the anchor were observed. The test results were compared with theoretical equation for the ultimate pull-out force. Also, the result of tests can be used to the finite element analysis program, $PENTAGON^{2D}$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.139-142
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• 2007

Malignant salivary gland tumor is rare neoplasm. In Korean population, retrospective study of malignant salivary gland tumor has not been performed. We analyzed 67 cases of malignant salivary gland tumors from 2001 to 2005 in Seoul National University Dental Hospital in Seoul, Korea. The mean age is 51.7 and the male to female ratio is 1:1.39. The most affected site is the palate. Histologically, the tumors were classified as adenoid cystic carcinoma(34.4%), mucoepidermoid carcinoma(31.3%), adenocarcinoma, NOS(11.9%), polymorphous low grade adenocarcinoma(3.0%), salivary duct carcionoma(6.0%), carcinoma ex pleomorphic adenoma(4.5%), myoepithelial carcinoma(4.5%), epithelial-myoepithelial carcinoma(1.5%), cyatadenocarcinoma(1.5%) and adenosquamous carcinoma(1.5%).

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.137.2-137.2
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• 2011

규표(圭表)는 남중하는 해의 그림자를 측정해 일 년의 길이와 절기를 알아내기 위한 관측 기기이다. 규표에 대한 우리 역사 기록에 따르면 조선시대에 8척과 40척 크기의 규표를 만들어 사용한 것으로 알려져 있다. 세종대에 간의대 서쪽에 설치한 40척 규표에 대해서는 그 구조와 크기가 상세히 기록되어 있지만 8척 규표에 대해서는 명종대의 관측 사실만이 남아있을 뿐이다. 8척 규표에 관한 국내 외 문헌과 중국에 남아 있는 유물을 조사하여 조선의 8척 규표 모델을 새롭게 복원하였다. 복원한 8척 규표는 주척(周尺, 1척=20.7cm)을 기준으로 규 21척, 표 8척의 크기이다. 오석으로 만든 규면에는 16척 길이의 눈금을 1분(2.07cm) 단위로 새겨놓았다. 청동으로 만든 표의 꼭대기에는 그림자를 명확히 나타내기 위해 길이 2척, 지름 1.2cm의 횡량(橫樑)을 설치하였다. 또한 횡량의 그림자를 정확하게 측정하기 위해 규면에 설치할 영부(影符)도 함께 연구 복원하였다. 규면에 새겨진 못(池)과 물홈(水渠)의 모양은 한국과 중국의 천문유물에 남아 있는 여러 자료와 구조적 기능을 고려해 결정하였다. 지금까지 국내에서 복원된 규표는 8척 규표에 대한 문헌 자료가 부족했기 때문에 40척 규표의 구조를 축소해서 만들어왔다. 이번에 복원한 조선의 8척 규표는 40척 규표의 축소 모형이 아닌 새로운 모델을 연구하여 제작한 것으로 한국천문연구원 앞뜰 간의 서편에 설치하였다.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2625-2627
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• 2002

A virtual laboratory for measurement and instrumentation must aim to realize an integrated environment. To achieve this goal, we designed and implemented a client/server distributed environment and developed a web-based virtual laboratory system for electronic circuits. The proposed virtual laboratory system is composed of four important components : Principle Classroom, Virtual Experiment Classroom, Evaluation Classroom and Overall Management System. Through our virtual laboratory, the learners will be capable of learning the concepts and theories related to electronic circuit experiments and how to operate the experimental equipments. Also, every activity occurred in our virtual laboratory is recorded on database and printed out on the preliminary report form. All of these can be achieved by the aid of the Management System. The database connectivity is made by PHP and the virtual laboratory environment is set up slightly differently for each learner. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing learning efficiencies as well as faculty productivity.

• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.113-121
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• 1988

The retention mechanism and separation of various aromatic sulfonic and carboxylic acids on reversed-phase liquid chromatographic column were studied in the mobile phase containing dodecyltrimethylammonium bromide (DTAB). The retention mechanism was found to be followed the ion-interaction model where the DTAB occupies a primary layer at the stationary phase while the sample anions and other co-anions in the system compete for forming the secondary layer. The capacity factors of samples were influenced by the several factors such as pH, concentration of various organic solvents, co-anions in the mobile phase and functional groups in sample molecules. Some mixtures of organic samples were attempted to separate under optimum condition.

• Journal of the Korean Ceramic Society
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• v.31 no.3
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• pp.298-304
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• 1994

Water-based magnetic fluids were made of the synthesized ultrafine magnetite with surfactants such as sodium oleate and loeic acid. The water-based magnetic fluid was prepared under the condition that added amounts of sodium oleate and oleic acid dissolved with NH4OH were 2.64$\times$10-2 mol, 1.5~2.0$\times$10-2 mol respectively. The water-based magnetic fluid was stable and should be dispersed well dispersion in the range of pH 9.0 to pH 11.0. As the solid content increased from 0.05 g/cc to 0.4 g/cc, the viscosity of water-based magnetic fluids increased from 2.5 cP to 152 cP and their magnetization at 5 KOe linearly increased from 3.1 emu/g to 26 emu/g. The aggregated powder after drying the water-based magnetic fluid was also successfully re-dispersed in dilute NH4OH solution and in kerosene.