• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.243-258
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• 2001

Gingival recession is exposure of the root surface with apical shift in the position of gingiva. The incidence of gingival recession is 8% in children and 100% after the age of 50. Recession tends to be found in patients with healthy gingiva, but more frequentely found in patients with periodontal disease, and it often causes mucogingival defects. Buccal surface of premolar is the area not only for severe gingival recession and cervical abrasion, but also the area of numbers of buccal frenum and less keratinized gingiva. Threrfore, the goal of this study was to observe the patients with periodontitis and examine whether there are clinical relations between gingival recession and cervical abrasion of premolar and other factors related with the condition of periodontal health. Generally healthy 218 patients who had periodontitis, aged between 18 and 78, were examined for depth of periodontal poket, width of attached gingival, gingival recession, cervical abrasion, and frenum of mid-buccal surface of premolar at the Department of Periodontics in Dankook University Dental Hospital and following is the result. 1. The average gingival recession and cervical abrasion of premolar with periodontal disease was 0.76mm and 0.29mm and each has 43% and 14% of incidence. Also the width of attached gingiva of mid-buccal surface was 1.77mm. the average periodontal pocket depth is 2.0mm and 47% of frequently seen was narrow single shaped frenum, and the interdistance of the frenum was mostly over 4mm. 2. With statistical significance(P<0.05), the incidence of gingival recession increased with age and was related much more with female than male, the first premolar than the second premolar, and with narrow attached gingiva and frenum. 3. With statistical significance(p<0.05), the incidence of cervical abrasion increased with age and was related with the area of the first premolar and narrow attached gingiva, but the sexual and frenum differences were not statistically significant (p>0.05). 4. The severity of gingival recession increased with age and was more related with female than male, the first premolar than the second premolar. And the area of narrow attached gingiva and frenum showed more gingival recession and the distance of frenum was more highly related than shape, and they were statistically significant (p<0.05). 5. With statistical significance(p<0.05), the severity of cervical abrasion increase with age and was observed at the first premolar and narrow attached gingiva. But the sexual and frenum differences were not statistically significant (p>0.05).

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3749-3754
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• 2012

Nanoporous carbons with a high specific surface area were prepared directly from thermoplastic acrylic resin as carbon precursor and MgO powder as template by carbonization over the temperature range, $500-1000^{\circ}C$. The effect of the carbonization temperature on the pore structure and $CO_2$ adsorption capacity of the obtained porous carbon was examined. The textural properties and morphology of the porous carbon materials were analyzed by $N_2/-196^{\circ}C$ and $CO_2/0^{\circ}C$ adsorption/desorption isotherms, SEM and TEM. The $CO_2$ adsorption capacity of the prepared porous carbon was measured at $25^{\circ}C$ and 1 bar and 30 bar. The specific surface area increased from 237 to $1251m^2/g$, and the total pore volumes increased from 0.242 to $0.763cm^3/g$ with increasing the carbonization temperature. The carbonization temperature acts mainly by generating large narrow micropores and mesopores with an average pore size dependent on the level of carbonization of the MgO-templated nanoporous carbons. The results showed that the MgO-templated nanoporous carbons at $900^{\circ}C$ exhibited the best $CO_2$ adsorption value of 194 mg/g at 1 bar.

• 한국통신학회논문지
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• 제34권12B호
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• pp.1329-1335
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• 2009

본 논문에서는 무선 인체 통신 네트워크에서 응급 데이터를 전송할 때 전송 지연시간을 보장하는 DCTW(Dual Channel Transmission Scheme for WBAN)기법을 제안한다. 무선 인체 통신 네트워크에서는 의학적인 응용을 고려하고 개발되었기 때문에, 의학적 데이터의 중요도에 따른 차등 전송 기법이 필요하다. DCTW에서는 응급 데이터 프레임의 전송을 위하여 협대역 채널을 사용하며 일반 데이터 프레임 전송을 위하여 광대역 채널을 사용한다. 협대역 채널을 통하여 응급데이터를 전송하기 때문에 긴급한 데이터를 보내고자 하는 노드가 데이터를 신속히 전송할 수 있도록 하여 전송 지연시간을 효과적으로 감소시켰다. 본 논문은 다양한 성능 분석을 통해 DCTW 기법이 다른 기법에 비해 우수함을 증명하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2063-2065
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• 2003

The control rod drive mechanisms in a reactor head are arranged too narrow for a human worker to approach. Moreover, the working environment is in high radiation area. In order to inspect defections in the surfaces of the reactor head and welding parts, a visual inspection device that can approach such a narrow and high radiation area is required. This paper introduces a tele-operated mobile robot for visual inspection of a reactor head, which has pan/tilt camera, fixed rear camera, ultrasonic collision detection system, and so on. Moreover, the host controller and digital video logging system are developed and integrated control software is also developed. The robot is operated by a wireless control, which gives flexibility for the inspection.

• 전기학회논문지P
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• 제62권3호
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• pp.139-144
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• 2013

In Korea, where most of the sites are narrow in space and their earth resistivity is relatively high, the spaces between grounding conductors are likely to be designed narrow in order to lower ground resistance and dangerous voltage below to the permitted safety values. In addition, ground nets are in the shape of square or rectangle depending on the location and size of the facilities and ground contact area, and inner conductors are laid out in grids like the pattern of nets. Nevertheless, with the existing designs, the marginal voltage for safety gets higher as the area is extended further outside, in comparison with that of inner mesh grounding, thus causing much difficulty maintaining them equipotential, and there exist limits in the burial, grounding grid design considering the dangerous voltage of muti-layered model in the constrained sites, was studied.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.91-97
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• 2011

In Korea, characterized in most cases by limited area or high earth resistivity, it is likely to design narrow distances between grounding conductors, with a view to keeping ground resistance and touch voltage below the safety margin values. A new grounding method is suggested, making use of double meshes, to lower touch voltage in a confined area, since it is difficult to lay the plugs under the ground with narrow gaps between them on a limited site. For the presentation of a new model, the suggested grounding system has been analyzed and studied in ground resistance, touch voltage and step voltage, using IEEE Std. 80 calculations and computer simulations.

• Journal of Korean Dental Science
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• 제15권1호
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• pp.92-99
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• 2022

This case report describes the immediate loading of narrow diameter implants in the mandibular incisor area using full-digital flow. The 3-dimensional position of the implants was planned using digital software, and the corresponding surgical template was fabricated. The implants were inserted immediately after extraction and on the same day, the interim abutment and bridge were placed. At 8 weeks after surgery, the stability of the implants was measured and a digital impression was made using a scan body. Customized titanium abutments and a cement-type full zirconia bridge were delivered. At 36 weeks' follow-up, no clinical or radiographic complications were detected, and the patient was satisfied with the results.

• 천문학회보
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• 제40권2호
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• pp.49.1-49.1
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• 2015

Star formation in galaxies that lie in dense environment tends to increase as the redshift of the cluster increases. At z~1.4, the situation turns to be complex; some clusters still harbor galaxies with vigorous star formation, and others are populated with relatively old, massive galaxies. We present the result from narrow-band photometric study of the fields around the radio galaxy 6CE 1100+3505 at z=1.44. Deep H- and H-narrow band data have been obtained using CFHT/WIRCAM which cover the corresponding wavelengths for redshifted $H{\alpha}$. While the number of IRAC 3.6, and $4.5{\mu}m$ selected sources show clear excess within the central ~1Mpc area from the radio galaxy, number of galaxies identified to show excess in H-narrow band is very small. We discuss the possible integrated star formation rate in this overdense structure, and the implication to the evolution of cosmic star formation rate as a function of environment.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.166-174
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• 2004

In urban area narrow commuter vehicles have attracted interest as a possible solution to reduce traffic congestion and parking problems. However, a narrow vehicle has an increased to overturn during hard cornering when compared to conventional vehicles. This tendency can be reduced by tilting it toward the inside of the turn. Two types of automatic tilting control systems which are Direct Tilt Control(DTC) and Steering Tilt Control(STC) have been developed. In this paper as one of the technique to improve the handling performance for the unusual vehicle the control system which blends both the DTC and the STC system is considered. It uses the merits of both the DTC and the STC system. As a control strategy for combination the switching control method is used. Finally, the fact that the unusual vehicle is safe under an emergency situation such as slippery road surface is proved by computer simulation.

• 한국습지학회지
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• 제11권1호
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• pp.29-37
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• 2009

본 연구는 경기도의 경안천 습지에서 번식 조류의 둥지 장소로서의 정수식물에 대한 선호성을 알아보고자 수행되었다. 6종의 조류가 정수식물에 번식하였으며 물닭 Fulica atra, 쇠물닭 Gallinula chloropus, 개개비 Acrocephalus orientalis, 덤불해오라기 Ixobrychus eurhythmus, 논병아리 Podiceps ruficollis, 뿔논병아리 Podiceps cristatus 등의 둥지가 발견되었다. 둥지 장소로 이용한 곳은 애기부들 Typha angustata, 갈대 Phragmites communis 와 줄플 Zizania latitolia 이었다. 특히 애기부들은 번식조류가 가장 선호하는 곳이었다. 그에 비해 쓰레기가 쌓인 곳이나 밀도가 빽빽한 곳은 둥지가 거의 없었다. 내부의 덤불에서는 둥지가 전혀 발견 되지 않았다. 소택지 내 둥지의 평균 밀도는 3.1개였으며 논섬이 17개/ha 로 밀도가 가장 높았다. 둥지 밀도는 소내섬 주변 지역이 광동교 인근보다 높았다. 이것은 애기부들의 규모와 수질과 관련될 것으로 보인다.