http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
개별검색 DB통합검색이 안되는 DB는 DB아이콘을 클릭하여 이용하실 수 있습니다.
통계정보 및 조사
예술 / 패션
<해외전자자료 이용권한 안내>
- 이용 대상 : RISS의 모든 해외전자자료는 교수, 강사, 대학(원)생, 연구원, 대학직원에 한하여(로그인 필수) 이용 가능
- 구독대학 소속 이용자: RISS 해외전자자료 통합검색 및 등록된 대학IP 대역 내에서 24시간 무료 이용
- 미구독대학 소속 이용자: RISS 해외전자자료 통합검색을 통한 오후 4시~익일 오전 9시 무료 이용
※ 단, EBSCO ASC/BSC(오후 5시~익일 오전 9시 무료 이용)
유공관 암거는 논의 타작물 재배를 위한 생산기반시설물에 있어서 배수성능을 향상시키기 위하여 사용되어왔다. 특히 무굴착 암거공법에 적용되고 있는 PVC 재질의 주름관은 경제성과 효율성 측면에서 간척농지 등에 적용될 가능성이 높다. 그러나 간척농지의 경우 염분이 다량 포함되어 있는 염수를 배출하여야 한다는 측면에서 일반적인 용수를 배출하는 경우와 다른 환경에 노출된다. 따라서 장기적으로 유공관 암거의 노후와 성능저하로 이한 파손으로 성능을 발휘하지 못할 수도 있다. 본 연구에서는 간척농지 등에 적용하기 위한 주름과 암거의 사용수명 예측을 위한 연구를 실시하였다. 사용수명을 예측하기 위한 time-shift factor를 결정하기 위하여 간척농지 및 사용된 재료의 차이가 있지만 간접적인 예측을 위하여 Litherland의 모델을 이용하였으며, 이를 통한 실험조건을 결정하였다. 간척농지와 유사한 환경을 노출하기 위하여 NaCl용액을 이용하였다. 비교대상으로는 증류수를 이용하였다. 시험은 20℃, 40℃, 60℃로 결정하였으며, 시험은 0일, 10일, 20일, 30일, 40일, 50일, 60일, 90일 및 100일간 노출 후 휨강도을 평가하였다. 시험결과를 분석하면 노출 시간이 증가할수록 휨강도는 감소하였다. 또한 온도가 높을수록 휨강도의 감소는 약간씩 증가하였다. 증류수 보다는 NaCl용액에 노출된 경우가 강도의 감소가 크게 나타났다.
Objectives: The purpose of this study is to evaluate the accuracy of the digital models from Cone beam computed tomography (CBCT) scans of orthodontic diagnostic models by comparing the Digital Imaging & Communication in Medicine (DICOM) file to Stereolithography (STL) conversion data obtained by various voxel sized CBCT machines with the digital model obtained by a 3D optical extraoral scanner. Materials and Methods: Three orthodontic diagnostic models were scanned with a 3D optical scanner and stored as STL file data. The three models were scanned with the 5 modes which were Object scan (100 μm), 300, 400 μm of RAYSCAN α+ and 300, 390 μm of Alphard 3030. The DICOM files were converted to STL file data. For each orthodontic model, two digital models obtained by CBCT and optical scanner were paired, and GOM inspect software was used to superimpose and obtain the deviation between two digital models. One way ANOVA test was performed to determine whether there is a statistical difference in the mean value of deviations between digital models by the 5 protocols. Results: In three diagnostic models, the mean values of the deviations between the digital model of the Object scan (100 μm) and the digital model of 3D optical scanner were the smallest in comparison with other image protocols and there was a statistically significant difference (p<0.001). The mean values of the deviations were in the range of 0.0967 ~0.1022 mm. On the other hand, deviations of STL data from 400 μm of RAYSCAN α+ showed the largest mean value from 0.4007 to 0.4534 mm. Conclusions: The STL file data of the Object scan (100 μm) of RAYSCAN α+ is more accurate than those of large voxel sized protocols of CBCT. It shows the availability as an orthodontic digital model.
Purpose: This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models. Materials and Methods: A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis. Results: The range of mean error between the cast scan model and the CBCT scan model was - 0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 μm. Conclusion: There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15 mm, and the average difference in model overlap was 53 μm. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.
This study was conducted to find out the best optimum design method for the design of reinforced concrete agricultural aqueduct abutment and pier structures. The mixed-discrete optimization and continuous optimization method were applied to the design of reinforced concrete agricultural aqueduct abutment and pier and the results of these optimization methods were compared each other. It is proved that mixed-discrete optimization method is more reliable, efficient and reasonable than continuous optimization method for the optimum design of the reinforced concrete agricultural aqueduct abutment and pier.
This study was conducted to find out the reasonable optimum design method of agricultural reinforced concrete structures. Selected design variables are the dimension of concrete section, reinforced steel area, and objective function is formulated by cost function. To test the reliability, efficiency, possibility of application and reasonability of optimum design method, both continuous optimization method and mixed-discrete optimization method were applied to the design of reinforced concrete superstructure of aqueduct and application results were discussed. It is proved that mixed-discrete optimization method is more reliable, efficient and reasonable than continuous optimization method for the optimum design of reinforced concrete agricultural structures.
Objective: The aim of this study was to compare the success rates of the manual and motor-driven mini-screw insertion methods according to age, gender, length of mini-screws, and insertion sites. Methods: We retrospectively reviewed 429 orthodontic mini-screw placements in 286 patients (102 in men and 327 in women) between 2005 and 2010 at private practice. Age, gender, mini-screw length, and insertion site were cross-tabulated against the insertion methods. The Cochran-Mantel-Haenszel test was performed to compare the success rates of the 2 insertion methods. Results: The motor-driven method was used for 228 mini-screws and the manual method for the remaining 201 mini-screws. The success rates were similar in both men and women irrespective of the insertion method used. With respect to mini-screw length, no difference in success rates was found between motor and hand drivers for the 6-mm-long mini-screws (68.1% and 69.5% with the engine driver and hand driver, respectively). However, the 8-mm-long mini-screws exhibited significantly higher success rates (90.4%, p < 0.01) than did the 6-mm-long mini-screws when placed with the engine driver. The overall success rate was also significantly higher in the maxilla (p < 0.05) when the engine driver was used. Success rates were similar among all age groups regardless of the insertion method used. Conclusions: Taken together, the motor-driven insertion method can be helpful to get a higher success rate of orthodontic mini-screw placement.
Recently, meteorological disasters have been increasing by climate change, excessive rainfall, and landslide. The purpose is to develop new fabricconcrete that can prevent and recover from damages because some of areas are vulnerable to meteorological disaster. Specifically, this technology canminimize time and space constraint when repairing the concrete structure and installing a formwork. The structure of fabric concrete is a mixture offabric concrete and a high-speed hardened cement, Silica sand, wollastonite mineral fiber, fabric material and waterproof PVC fabric. In this study, theratio of mechanical properties and durability of the fabric concrete mixture was evaluated by deriving the binder: silica sand mix ratio of the fabricconcrete mixture and substituting part of the cement amount with wollastonite mineral fiber. Best binder in performance evaluation: Silica sand mixratio is 6: 4 and the target mechanical performance and durability are the best when over 15% wollastonite binder is replaced by silicate mineral fiber.