부여 백제시대 가마터의 고고지구자기 연구

이윤수,서광수,서만철 공주대학교 문화재보존과학연구소 2004 문화재과학기술 Vol.3 No.1

충남 부여군 가마터에 대한 고고지자기 연구를 실시하였다. 13개의 가마 시료로부터 구한 특성잔류자화는 열화학작용에 의해서 생성된 자철석에 의해서 수행되며, 가마가 575℃이상 가열된 후 식으면서 그 당시의 지구자기장에 의해서 획득된 것으로 밝혀졌다. 이번 연구에서 구한 특성잔류자화의 그 평균편각과 평균복각은 각각 3.9˚E와 39.4˚ (a_(95)=3.2˚)로서, 한반도의 시험적 영년변화곡선에 대비하여 구한 특성잔류자화의 획득 시기는 서기 1,583년(+44년, -36년)이다. The archaeomagnetic study is examined to determine archomagnetic age of the kiln located in Buyeo area, Chungnam province. The results document that the characteristic remanent magnetization(ChRM) for 13 samples is carried by magnetite grains formed by a thermochemical activity during cooling from more than 575˚C. The Site mean direction (declination and inclination) for the ChRM is 3.9˚E and 39.4˚ (a_(95)=3.2˚). We conclude that the ChRM acquired in A.D. 1,583 (+44 yr, -36 yr), correlating the t-KPSV (tentative Korea Paleoselcular Variation) curve.

일 최저기온 공간내삽을 위한 지형기후학적 최적 공간규모

정유란,서희철,윤진일,이광회 한국농림기상학회 2003 한국농림기상학회지 Vol.5 No.4

Cold air accumulation plays a critical role in formulating daily minimum temperature in complex terrain on radiative cooling nights, and spatial interpolation can be improved by accommodating this important topoclimatic variable. Little is known about the spatial scale for computing cold air accumulation which influences daily minimum temperature. Air temperature was measured at 10-minute intervals during September 2002 - February 2003 at eight locations within a 1 by 1 km hilly orchard area. Minimum temperature data for suspected radiative cooling nights were collected, and the deviations from reference observations at a near-by KMA automated weather station were calculated. A digital elevation model with a 10m cell size was used to calculate the cold air accumulation at 8 locations. Zonal averages of the cold air accumulation were computed for each location by increasing the cell radius from 1 to 10. Temperature deviations were regressed to a common logarithm of the smoothed averages of cold air accumulation to derive a linear relationship between the local temperature deviation and the site topography. The highest coefficient of determination (r² = 0.78) was found at a cell radius of 5, which corresponds to an approximately 1 ha boundary surrounding the point of interest.

연마방법에 따른 탄성의치의 표면거칠기와 Candida albicans의 부착율 변화

오주원,서재민,안승근,박주미,강철균,송광엽 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.2

연구 목적: 본 연구는 탄성의치 제작 시 주로 사용되는 polyamide를 수종의 연마방법을 사용하여 처리 후 Candida albicans의 부착정도와 표면거칠기를 비교하고자 하였다. 연구 재료 및 방법: 25×15×2 mm 크기의 polyamide 시편을 4군으로 나누어 연마재를 사용하여 기공용 lathe 연마하는 방법(기공실내 연마방법)과 각기 다른 2종의 실리콘 포인트로 진료실내 연마하는 방법, 그리고 실리콘포인트 연마 후 pumice로 연마하는 방법으로 처리하였다. C. albicans의 부착성을 평가하기 위해 5×106 CFU/ml의 C. albicans 현탁액에 시편을 2시간 동안 침적하였고 5회 수세처리 후 한천배지에서 배양하였다. 그리고 주사전자 현미경(JSM-5900, JEOL LTd., Tokyo, Japan) 촬영을 시행하였다. Profilometer (Surf-pak; Kawasaki, Japan)를 이용하여 표면거칠기를 측정하였고 통계처리를 위하여 SPSS 18.0 프로그램을 사용하였다. 일원변량분석으로 비교 분석하였고 사후검증은 C. albicans의 부착성 검증을 위해 Scheffe test를 시행하였으며 표면조도검증을 위해 Tamhane’s T2 test를 시행하였다(α=.01). 결과: 최대 거칠기 값을 보인 군은 2단계의 연마용 버를 사용한 것으로 0.32 ㎛±0.10 값을 나타냈으며, 가장 낮은 거칠기 값을 보인 것은 tungsten carbide를 사용하지 않고 기공용 lathe로만 연마를 한 군으로 0.02 ㎛±0.00의 거칠기 값을 나타냈다. C. albicans 부착 실험에서는 기공용 lathe만을 이용한 연마방법이 가장 적은 부착수를 보였으며 다른 세 군과 유의한 차이가 발견되었다(P<.01). 결론: 표면거칠기 및 미생물 부착능 실험 결과 기공실 연마만을 시행한 경우 유의하게 낮은 거칠기 값과 부착율을 보였다. Pumice로 추가 연마한 군은 진료실연마를 시행한 군에 비해 낮은 거칠기 값을 보였으나 C. albicans 부착에 있어서는 유의한 차이를 보이지 않았다(P>.01). Purpose: The purpose of this study was to compare the effect of 3 chairside polishing methods and laboratory polishing methods on surface roughness and C. albicans adhesion of polyamide denture base. Materials and methods: Using contact profilometer, the surface of polyamide specimens (25×15×2 mm) was studied after conventional polishing without finishing and after chiarside polishing with 2 chiarside polishing kits and chairside-pumice polishing following finishing with tungsten carbide bur. To evaluate the adhesion of C. albicans, C. albicans suspension was overlayed on the test specimen. And the specimens were incubated for 2 hours. Imprint culture method was achieved and counted the colony on the agar plate. Polished polyamide were evaluated using a scanning electron microscope. The statistics were conducted using one-way ANOVA and in case of difference, Scheffe test and Tamhane’s T2 test were used. Results: Surface roughness (Ra) of surfaces polished with 2 chairside polishing kits had higher than conventional polishing and pumice polishing. The highest roughness value was 0.32 ± 0.10 ㎛, and the lowest was 0.02 ± 0.00 ㎛. The adhesion of C. albicans on the specimens polished with chairside polishing group and pumice polishing group were increased than conventional polishing group (P<.01). Conclusion: Conventional laboratory polishing was found to produce the smoothest surface and the lowest adhesion of C. albicans. Two groups polished with Chairside polishing kits were similar with respect to surface roughness. Surface of the specimen polished with pumice is significantly smoother than 2 chairside polishing groups, but the result of C. albicans adhesion is that group polished with pumice was similar with 2 chairside polishing groups (P>.01).

경연 대회를 통한 초ㆍ중고생의 창의력 신장 효과에 관한 연구

이희복,육근철,류해일,김현섭,김희수,박달원,유병환,김선효,김여상,서광수,변두원,서명석,배성효,박종석,심규철,이성희 공주대학교 과학교육연구소 2001 과학교육연구 Vol.32 No.1

미래 사회를 대비하기 위한 개인의 개성을 존중과 창의적인 능력을 지닌 인간을 양성을 목적으로 충청남도 지역의 초 ㆍ 중고등학생들을 대상으로 한 창의력 경연대회가 공주대학교 과학교육연구소에서 개최되었다. 충청남도 초 ㆍ중 ㆍ 고등학생들을 대상으로 실시한 창의력 경연대회는 창조적 아이디어를 내어 스스로 문제를 해결해 나갈 수 있는 교육 프로그램을 제공하는 좋은 기회였음이 확인되었으나, 일부의 팀에서만 참신하고 재미있는 아이디어들이 제안되었다. 여학생의 참가자 수가 상당히 증가하였으며, 대체적으로 입상권의 학생들의 상당 부분이 여학생이라는 것이 특이할만하다. 학년이 올라감에 따라서 창의적인 아이디어를 내는 양이나 질에 있어서 뒤떨어지는 것으로 분석되었으며, 토론 학습의 적응력이 미흡하고 발표력 및 청취력에 있어서도 떨어지는 것으로 나타났다. 따라서 중 ㆍ고등학교의 학교교육에서도 학생들에게 프로젝트형 탐구학습 프로그램의 적용은 물론 토론식 수습을 통한 학생들의 사고의 전환의 기회를 제공해야 할 것으로 사료된다. The creativity competition was held to foster the creativity of elementary and secondary school students in the Institute of Science Education, Kongju national University. It was found that the creativity competition effected on the improvement of inventing creative ideas and problem solving activities. But, only some competitors participated in semifinal and final contests, presented original and interesting ideas. More female students participated in competition than last year. More female participants were awarded a prize than males. Totally, participants were defective in discussion and communication, and presentation and listening ideas. Increasing grades correlated inversely with creativity and originality. There is need of inquiry project teaming programs and presenting opportunities of conversion of thinking by discussing instructions in school

Topology Optimization of the Decking Unit in the Aluminum Bass Boat and Strength Verification using the FEM-program

Kwang-Cheol Seo,Jin Gwak,Joo-Shin Park 해양환경안전학회 2018 해양환경안전학회지 Vol.24 No.3

The objective of this paper is to optimize the cross-section of aluminum decking units used in the bass boats under operating conditions, and to verify the optimized model from the results via by ANSYS software. Aluminum decking unit is needed to endure specific loading while leisure activity and sailing. For a stiffer and more cost-neutral aluminum decking unit, optimization is often considered in the naval and marine industries. This optimization of the aluminum decking unit is performed using the ANSYS program, which is based on the topology optimization method. The generation of finite element models and stress evaluations are conducted using the ANSYS Multiphysics module, which is based on the Finite Element Method (FEM). Through such a series of studies, it was possible to determine the most suitable case for satisfying the structural strength found among the phase-optimized aluminum deck units in bass boats. From these optimization results, CASE 1 shows the best solution in comparison with the other cases for this optimization. By linking the topology optimization with the structural strength analysis, the optimal solution can be found in a relatively short amount of time, and these procedures are expected to be applicable to many fields of engineering.

Experimental investigation of dynamic trim control devices in fast speed vessel

Kwang-Cheol Seo,Nithin Gopakumar,Mehmet Atlar 한국항해항만학회 2013 한국항해항만학회지 Vol.37 No.2

The displacement Deep-V catamaran concept was developed in Newcastle University(UNEW) through development of the systematic Deep-V catamaran series. One of the most important Deep-V catamaran launched to date is Newcastle University’s own multi-purpose research vessel, The Princess Royal. The vessel was launched in 2011 and enhanced the Deep-V catamaran concept further with the successful adoption of a novel anti-slamming bulbous bow and tunnel stern for improved efficiency. It was however identified that the vessel has substantial amount of dynamic trim that limited the visibility of the captain. The dynamic trim also increased the wave-making resistance thereby preventing the vessel from attaining its maximum speed in certain sea states. This paper therefore presents the application of devices such as Trim Tabs, Interceptors, Transom Wedges and Integrated Transom Wedges-Tabs to control the dynamic trim and improvement of fuel efficiency of the vessel. All of these energy saving devices were fitted into a model for tests in Newcastle University’s Towing Tank. Model test verification confirmed that the optimum appendage was the interceptors, they produced a 5 % power saving and 1.2 degree trim reduction at 15 knots, and investigations of full scale trials will be scheduled with and without application of device to compare the improvement of performance.

Experiment with Axiom Propeller in Cavitation Tunnel

Seo, Kwang-Cheol The Korean Society of Marine Environment and safet 2014 海洋環境安全學會誌 Vol.20 No.3

The Axiom propeller is a unique 3 bladed propeller and it enables to generate the same amount of thrust going ahead as it does going astern because of its 's' type skew-symmetric blade section. A earlier variant of the design (Axiom I propeller) performed a low propeller efficiency, maximum 35 % efficiency, and further blade outline design was carried out to achieve a higher efficiency. The optimized new blade outline (Axiom II propeller) has more conventional Kaplan geometry shape than Axiom I propeller. Model tests of open water performance and propeller cavitation for both propellers were conducted at Emerson Cavitation Tunnel in order to compare their performances. Experiment results revealed that Axiom II propeller provides a maximum 53 % efficiency and provides better efficiency and cavitation performance over the Axiom I propeller under similar conditions.

Experiment with Axiom Propeller in Cavitation Tunnel

Kwang-Cheol Seo 해양환경안전학회 2014 海洋環境安全學會誌 Vol.20 No.3

The Axiom propeller is a unique 3 bladed propeller and it enables to generate the same amount of thrust going ahead as it does going astern because of its ‘s’ type skew-symmetric blade section. A earlier variant of the design (Axiom I propeller) performed a low propeller efficiency, maximum 35 % efficiency, and further blade outline design was carried out to achieve a higher efficiency. The optimized new blade outline (Axiom II propeller) has more conventional Kaplan geometry shape than Axiom I propeller. Model tests of open water performance and propeller cavitation for both propellers were conducted at Emerson Cavitation Tunnel in order to compare their performances. Experiment results revealed that Axiom II propeller provides a maximum 53 % efficiency and provides better efficiency and cavitation performance over the Axiom I propeller under similar conditions.

Experimental investigation of dynamic trim control devices in fast speed vessel

Seo, Kwang-Cheol,Gopakumar, Nithin,Atlar, Mehmet Korean Institute of Navigation and Port Research 2013 한국항해항만학회지 Vol.37 No.2

The displacement Deep-V catamaran concept was developed in Newcastle University(UNEW) through development of the systematic Deep-V catamaran series. One of the most important Deep-V catamaran launched to date is Newcastle University's own multi-purpose research vessel, The Princess Royal. The vessel was launched in 2011 and enhanced the Deep-V catamaran concept further with the successful adoption of a novel anti-slamming bulbous bow and tunnel stern for improved efficiency. It was however identified that the vessel has substantial amount of dynamic trim that limited the visibility of the captain. The dynamic trim also increased the wave-making resistance thereby preventing the vessel from attaining its maximum speed in certain sea states. This paper therefore presents the application of devices such as Trim Tabs, Interceptors, Transom Wedges and Integrated Transom Wedges-Tabs to control the dynamic trim and improvement of fuel efficiency of the vessel. All of these energy saving devices were fitted into a model for tests in Newcastle University's Towing Tank. Model test verification confirmed that the optimum appendage was the interceptors, they produced a 5% power saving and 1.2 degree trim reduction at 15 knots, and investigations of full scale trials will be scheduled with and without application of device to compare the improvement of performance.

Topology Optimization of the Decking Unit in the Aluminum Bass Boat and Strength Verification using the FEM-program

Seo, Kwang-Cheol,Gwak, Jin,Park, Joo-Shin The Korean Society of Marine Environment and safet 2018 해양환경안전학회지 Vol.24 No.3

The objective of this paper is to optimize the cross-section of aluminum decking units used in the bass boats under operating conditions, and to verify the optimized model from the results via by ANSYS software. Aluminum decking unit is needed to endure specific loading while leisure activity and sailing. For a stiffer and more cost-neutral aluminum decking unit, optimization is often considered in the naval and marine industries. This optimization of the aluminum decking unit is performed using the ANSYS program, which is based on the topology optimization method. The generation of finite element models and stress evaluations are conducted using the ANSYS Multiphysics module, which is based on the Finite Element Method (FEM). Through such a series of studies, it was possible to determine the most suitable case for satisfying the structural strength found among the phase-optimized aluminum deck units in bass boats. From these optimization results, CASE 1 shows the best solution in comparison with the other cases for this optimization. By linking the topology optimization with the structural strength analysis, the optimal solution can be found in a relatively short amount of time, and these procedures are expected to be applicable to many fields of engineering.