• 박물관보존과학
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• 제21권
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• pp.41-52
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• 2019

2017년 실시한 경주 고선사지 삼층석탑의 정밀안전진단 과정에서 1975년 석탑 이전 시 2층 탑신석이 회전되었을 가능성이 제기되었다. 이에 일제강점기와 1975년 해체 전후의 관련정보와 사진자료 등을 수집하여 석탑부재에 대한 정밀조사를 진행하였다. 분석결과 1943년 개건 전·후에는 부재의 변동이 없었으나 1975년 이전과정에서 2층 탑신석이 오른쪽 방향으로 90도씩 회전하였고, 1층과 2층의 옥개석 1매가 서로 바뀌었음이 확인되었다. 이러한 석탑부재의 변동이 오류인지를 확인하기 위해 3차원 스캐닝 정보를 토대로 정밀계측과 옥개석 부재의 재구성 등을 통해 검증해 보았다. 검증결과 현재 1층 옥개석 4매의 두께는 75~76cm, 2층은 78~79cm로 특이점이 발견되지 않았고, 옥개석 간 연접선의 형상 역시 자연스러웠다. 이에 고선사탑은 조성이후부터 1943년 사이에 중수(重修)된 숨은 연혁이 존재하며, 고대에 발생한 오류를 1975년 바로잡은 것이라고 결론지었다. 아울러, 2층 탑신석의 회전은 옥개석 위치변동에 따른 부수적 조치일 가능성을 제시하였다.

• 한국어류학회지
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• 제25권4호
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• pp.208-215
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• 2013

2011년 4~6월까지 충청북도 괴산군 청천면 달천 (조사지점 1)과 단양군 가대면 어상천 일대(조사지점 2)에서 묵납자루의 산란숙주조개 선호도를 실시하였다. 조사지점 1의 자연상태에서 묵납자루의 산란숙주조개 내 산란율은 곳체두드럭조개에 63.6%, 작은말조개 2.1%로 나타났고 작은대칭이와 칼조개에서 산란된 개체는 없었다. 묵납자루가 산란한 알 및 자어의 수는 곳체두드럭조개 1~41 ($12.0{\pm}9.21$)개, 작은말조개 6개였다. 실험 1의 결과 묵납자루는 곳체두드럭조개에만 산란하였고 산란율은 60%였으며, 산란한 알 및 자어의 수는 1~19 ($6.8{\pm}5.44$)개였다. 실험 2에서 묵납자루는 곳체두드럭조개, 작은말조개, 작은대칭이 모두에 산란하였고 산란율은 각각 75.0, 42.9, 21.4%였으며, 산란한 알 및 자어의 수는 각각 1~35 ($13.0{\pm}8.80$)개, 1~26 ($5.2{\pm}6.92$)개, 2~19 ($8.6{\pm}5.64$)개였다. 실험 3에서 묵납자루는 곳체두드럭조개에만 산란하였고 산란한 알은 2~10 ($6.7{\pm}4.16$)개였다. 묵납자루는 1종의 조개에만 산란하는 특이종(specialist)이라기보다는 일반종(generalist)이라고 생각되며, 곳체두드럭조개를 가장 선호하는 것으로 나타났다.

• 한국지반환경공학회 논문집
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• 제21권1호
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• pp.5-12
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• 2020

지진원으로부터 전파되는 진동은 거리에 따른 감쇠와 지형 혹은 지질구조에 따라 지역마다 다른 증·감폭 특성을 가진다. 지진원에서 기반암까지의 전파되는 진동은 이격거리에 따른 감쇠의 영향이 크며, 이는 감쇠식을 통해 쉽게 추정할 수 있다. 하지만 지표면에 전달되는 진동 추정은 기반암 상부에 위치한 토층 고유주기의 영향을 받기에 위치별 지질정보 파악이 중요하다. 지질정보 기반 진도 추정을 위해 지반조사 자료가 필요하며, Vs 주상도가 없을 경우 표준관입시험을 통해 대상지반의 강도 및 특성 파악에 주로 사용된다. 국토지반정보 포털시스템에서는 국내 지반에서 수행된 지반조사자료를 통합하여 관리하고 있으며, 표준관입시험 정보가 약 40만공을 구축되어 있다. 본 연구에서는 지반정보를 기반으로 체감형 진도정보 산출을 위해 권역별로 증폭계수 정량화 가능성을 검토하였다. 이때 SPT-N치를 자료를 통해 전단파 주상도를 생성하고, 대상지역에 지반응답해석을 수행하였다. 권역별 증폭계수와 지진파의 주기별 진도 분포는 해석방법 및 권역설정에 따라 큰 차이를 보였다.

• 한국환경복원기술학회지
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• 제22권6호
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• pp.97-114
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• 2019

This study aims to analyze the effect of urban ecosystem restoration projects by evaluating the short-term restoration performance of the project sites, from both qualitative and quantitative evaluations. In this study, for the qualitative evaluation, we derived the evaluation frame from previous studies and literature. For the quantitative evaluation, the changes in ecological connectivity after the restoration project were described using landscape permeability and network analysis. In addition, changes in habitat quality after the restoration project were evaluated by using InVEST Habitat Quality Model. These evaluations were applied to the three natural madang (ecological restoration) projects and two ecosystem conservation cooperation projects. As a result, three categories, 10 indicators, and 13 sub-indicators were derived from literature as the evaluation frame for this study. In the case of quantitative evaluation of restoration performance, habitat quality increased by 45% and ecological connectivity by 37% in natural-madang, and habitat quality by about 12% and ecological connectivity by about 19% in ecosystem conservation cooperation projects. This implies that the ecological restoration project can increase the ecological connectivity and the habitat quality of degraded sites even in a short period of time by improving the land-cover and land use. The results by applying the evaluation frame indicated that ecological and environmental factors and the ecological functions were improved by the restoration works, even though the magnitude of performances were diverse depending on the specific evaluation items, project type, and site characteristics. This study clarified that the success of ecological restoration project should be assessed by both of the short-term and long-term goals, which can be achieved by the maintenance and sustainable management, respectively.

• 대한치과보철학회지
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• 제33권2호
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• pp.317-334
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• 1995

The purpose of this study was to compare the bone formation, maturation around HA-and titaniumcoated dental implants in dog. 5 hydroxyapatite coated IMZ implants and 5 titanium coated IMZ implants were placed into the previously extracted site in the mandible of 5 adults dogs. All dogs were injected intravenously Tetracycline, Alizalin red S, and Calcein for bone fluorescent labelling, After the experimental period of 16weeks, the dogs were sacrificed and tissue samples around the implants were obtained. Microscopic observations(ligth, polariged and fluorescence microscope), morphometric analysis, line profile with EPMA, and quantitative analysis for Ca,P, and Ti were performed. The results were as follows ; 1. Bone maturations around the implants were relatively lower than those of natural teeth. No significant differences in bone maturation and remodeling patterns were observed between the two implants groups. 2. Calcification of bone surrounding the implants was initiated in 8-11 weeks for HA-coated implants, while it took 11 weeks or more for Ti-coated implants. 3. Bone-to-implants contact ratio of 82.63% was recorded for HA-coated group and 72.25% for titanium coated group, with no significant difference between the two groups. 4. Bone around the implants exhibited reduced quantity of Ca and P in the $100{\mu}m$ region relative to natural teeth, while the rest of the regions showed no statistical differences. No significant differences were found between the two implant groups. 5. There was a separation of HA layer from the implant core and subsequent infiltration of inflammatory cells into the resulting space in the HA-coated implants, and evidences of phagocytosis of HA particles by macrophages. Bone calcification was more rapid around HA-coated implants compared to titanium-coated implants, but HA coated implants did not show any significant differences either in the degree of calcification or the bone-to-implant contact ratio over Ti coated implants. HA coated implants may have complications associated with HA absorption and separation of HA layer from the implant core.

• 상하수도학회지
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• 제21권1호
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• pp.91-99
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• 2007

It is well-known that the presence of NOM (natural organic matter) in water has a negative effect on removing taste and odor compounds by activated carbon adsorption. Therefore, various means such as enhanced coagulation are applied to reduce the NOM. The presence of taste & odor compounds in drinking water even parts per trillion, is enough to generate customer dissatisfaction. Therefore, the aim of this study was to evaluate carbon usage rate (CUR) for conventional coagulation (CC) and enhanced coagulation (EC) in order to improve the efficiency of adsorption of taste and odor compounds. Also, Effect of CC and EC on molecular weight fraction and the early stage breakthrough of 2-MIB and Geosmin are evaluated. When the enhanced coagulation was adapted for pretreatment for activated carbon adsorption the operation period could be prolonged by 3.5~4 times. CUR for CC was about 2 times greater than CUR for EC and this means that EC has more adsorption capacity than CC. To analyze effect of EC and CC on breakthrough of 2-MIB quantitatively, adsorbed NOM mass was calculated based on unit mass of activated carbon. In the early stage breakthrough of 2-MIB, total adsorbed NOM was 23.72mg/g for CC and 34.56mg/g for EC. Therefore, it is shown that the early breakthrough term of 2-MIB and Geosmin was improved due to increased adsorbability. The low-molecular-weight NOM (500~2000Da) compounds were the most competitive, participating in direct competition with 2-MIB for adsorption site.

• 한국대기환경학회지
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• 제12권4호
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• pp.495-504
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• 1996

The concentrations of dimethylsulfide (DMS) were determined from both seawater and the overlying atmosphere from a station located in the Masan Bay area during a ten-day field campaign period of January 1996. The resulting data were also used to derive saturation ratios (SR) as well as sea-to-air fluxes of DMS. The concentrations and fluxes of DMS for both reservoirs varied extensively over two to three orders of magnitude: DMS in air and seawater were measured at 9 to 4,300 pptv (mean: 600 $\pm$ 1, 170, N=18) and at 0.24 to 10 nM (4.0 $\pm$ 3.4, N=13), respectively, while its fluxes were found from 0.02 to 23 mol $m^{-2} day^{-1} (3.1 \pm 6.8, N=11)$. A comparative analysis between our data and previously reported ones indicate that its atmospheric concentrations are abnormalously high, but its seawater counterparts are slightly lower than expected. In light of high pollution levels of organic-rich materials in and the associated high biological productivity of the study area, the sea-to-air-fluxes derived are notably low relative to those values typically reported from the coastal areas. These complicated features of DMS distributions/fluxes in the study site indicate that the near-by port- based anthropogenic activities from various industrial plants strongly interfere with natural processes leading to the production and release of DMS. It was however striking to find out relatively strong signals of diel cycle in its saturation ratios, concentration gradients between seawater and atmosphere, and the associated fluxes. Although it is yet difficult to provide meaningful explanations for the observed phenomena, the existence of clear diel cycle in some DMS-related parameters suggests that the natural processes may nonetheless exert important controls on the regional cycling of atmospheric sulfur species, of particular DMS.

• 한국지반공학회논문집
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• 제36권6호
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• pp.17-34
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• 2020

일반적으로 잔교식 구조물의 내진설계를 위한 응답스펙트럼 해석 시 기준서들에서는 지진응답해석을 통해 증폭된 가속도를 입력가속도 활용하도록 제시하고 있으나, 기준서에 따라 방법이 상이하여 설계 시 혼란을 야기할 수 있다. 이에, 본 연구에서는 동적원심모형실험을 통해 지반 내 다양한 깊이에서 지반 가속도를 산정하였으며, 산정된 지반가 속도를 활용하여 응답스펙트럼 해석을 수행하였다. 이후 실험 및 해석을 통해 도출된 잔교식 안벽 구조물의 모멘트 결과를 비교하였으며, 응답스펙트럼 해석 시 적절한 입력지반가속도를 결정하기 위한 방법을 제시하고자 하였다. 실험 및 해석을 비교한 결과, 탄성 지반 스프링을 적용하는 경우 구조물의 고유주기를 가장 적절하게 모사하는 것으로 나타났으며, 상부 지표면에서 증폭된 지진파를 입력가속도로 활용하는 것이 사질토 지반에 관입된 구조물 응답을 가장 합리적으로 모사하는 것으로 나타났다.

• 한국지진공학회논문집
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• 제11권4호
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• pp.1-11
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• 2007

This paper verifies the difference of the seismic behavior and seismic damage of the neighboring two reinforced concrete piers damaged by the 1995 Hyogoken Nanbu earthquake. The two piers were almost the same size, carrying slightly different dead load, and were provided with the same reinforcement arrangement except the amount of longitudinal reinforcement at the bottom portion of the piers. The pier with more reinforcement was completely collapsed due to this near field earthquake by shear failure at the longitudinal reinforcement cut-off while the other was only damaged at the bottom by flexure even though the longitudinal reinforcement cut-off was also existed at the mid height of the pier. According to the results of the pseudo dynamic test, the seismic damage was recognized to be greatly dependent on the ground motion characteristics even though the employed ground motions had the same peak acceleration. The severe damage was observed when the test employed the seismic wave that had strong influence to the longer period range compared to the initial natural period of the pier. On the other hand, based on the similar model experiment, the defect of gas-pressure welded splice of longitudinal reinforcement was revealed to save the piers against collapse due to the so-called fail-safe mechanism contrary to the intuitive opinion of some researchers. It was concluded that the primary cause of the collapse of the pier was the extremely strong intensity and peculiar characteristics of the earthquake motion according to both the site-specific and the structure-specific effects.

• 한국실내디자인학회논문집
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• 제26권5호
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• pp.65-74
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• 2017

The purpose of this research is to analyze characteristics of street elements when pedestrians have a view in the street. The research was utilized eye-tracking experiment and two times survey before and after experiment. The experiment is composed as follows. The data collection was conducted two days period from March 30 to 31, 2017. There were 43 participants who were all male and undergraduate students. In the data recording, the stimulus image was presented 65 seconds on a 23-inch monitor. Prior to analyzing data, the images were represented into five elements of AOI(area of interest). The fixation rate was divided by a period such as 'fixation time' and 'fixation count' parameters. The results were additionally obtained by linking analysis with the area ratio of AOI, time series analysis, and questionnaire. First of all, both building signs and advertisement standing boards draws attentions in participants. From a comparison between fixation rate and survey, the data have negative perspective view. Second, the advertisement standing boards are more eye-catching than other elements regardless of AOI size. It shows the priority of elements what should be developed in the environment. Third, the pavement is rarely seen in the fixation rate. Fourth, the trees are not a long frequency but viewed as a positive element. People want to keep the natural site in the street. In summative research, this method of extracting eye movement data would be provided a foundation data for developing streetscape plan based on scientific factors.