http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
석탄폐석의 활용에 관한 실험적 연구 : 도로 토공재를 중심으로
박흥규,김남옥 관동대학교 1994 關大論文集 Vol.22 No.2
Statistics has it that coal refuses discarded every year through our coal mines amount to approximate 7 million tons,some 3 to 4 hundred tons piled on each coal mine.Recent years have witnessed the ever-in-creasing problems of environmental pollutions such as stream pollution,forest damage,and public nuisances,which are allegedly caused by coal refuses. In this regard, a few people interested are quite worried about the continual collapse of mining businesses. This we are able to attribute to the industrial rationalization policy of the government during 1990's. Here we consider that the radical method of mass consumption of coal refuses lies in the good use of them as construction materials. This,we are sure,will enable us to clear up a difficult problem of gathering aggregate,to expect to obtain the result of curtailment of expenditure in exploiting the coal mines with the rise-up of added value,and also to make activated community development of coal mine areas which are still stagnant,and also to better the environment in terms of the proper use of refuses. Thus we attempt to investigate the geotechnical characteristics of coal refuses, examining the possibility of the improvement method of soft soil for the strength increase.
미세 전기기계 시스템용 알루미늄 박막의 탄성계수 및 항복강도 평가
주영창,손동일,관동일 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.3
Nowadays, the aluminum films have wide application in micromechanical devices such as micro sensors and actuators, so that their mechanical properties come to be very important for reliability evaluation. However, there is no standardized method to evaluate the mechanical properties of material used in MEMS (micraelectromechanical system) device since the measured mechanical properties are influenced by many factors such as surface condition, friction force, etc. Hence, we intended to evaluate the mechanical properties of thin film in our study, which is important in mechanical operation. Because MEMS devices are usually operating in elastic range, the Young's modules and yield strength were evaluated by using microcantilever beam technique. First, Al cantilever beams were fabricated using the silicon bulk micromachining technology to have various film thickness. And then, the load-displacement curve was obtained by nanoindentation method. The linear relation in elastic range was utilized in deriving the Young's modulus of Al film, which gives us reproducible result regardless of film thickness. In high load range, the deviation from the linear relation was detected, so that the yield strength of Al film could be evaluated. It is found that the yield strength increases with decreasing film thickness. By applying the misfit dislocation theory and the Hall-Petch relation, the theoretical estimation could predict well the trend of yield strength.
GPS 상시관측소 인근의 나무에 의한 GPS 관측치 누락 및 사이클슬립 발생 빈도 분석
박관동,손동효,김두식 한국국토정보공사 2013 지적과 국토정보 Vol.43 No.2
The data quality at the permanent GPS site, which is considered as the control point in RTK or Network RTK surveys, directly affects the surveying efficiency. Because most of the GPS stations operated by National Geographic Information Institute in Korea are surrounded by trees, GPS observables frequently get lost and the frequency of cycle slip increases. In this study, we developed methods to analyze the missing data visually and quantitatively, and proved positive correlations between the frequency of cycle slips and trees. Through the test on six permanent sites in Korea, we found that the missing ratio is at least twice higher in the summer months than that of winter months when all the leaves are fallen down. In addition, it was found that the frequency of cycle slips was two to five times higher in summer months than winter. RTK와 네트워크 RTK 측량의 경우 기준점 역할을 하는 GPS 상시관측소의 자료품질이 측량 효율성에 직접적인 영향을 준다. 국내에서 운영 중인 대부분의 국토지리정보원 상시관측소 인근에는 나무들이 위치하고 있어 GPS 관측치가 누락되고, 사이클슬립이 빈번하게 발생하고 있다. 이 논문에서는 관측치가 누락되는 현상을 시각적·정량적으로 분석하는 방법을 고안하고, 사이클슬립 발생빈도와 나무와의 상관관계를 증명하였다. 국내 6개 관측소를 대상으로 분석한 결과 나뭇잎이 떨어지는 겨울철이 여름철에 비해 데이터 누락률이 최소 2배 이상 감소하였다. 사이클슬립 발생빈도의 경우 여름철이 겨울철보다 2배에서 5배정도 높은 것으로 나타났다.
Accuracy Comparison of GPT and SBAS Troposphere Models for GNSS Data Processing
박관동,이해창,김미소,김영국,서승우,박준표 사단법인 항법시스템학회 2018 Journal of Positioning, Navigation, and Timing Vol.7 No.3
The Global Navigation Satellite System (GNSS) signal gets delayed as it goes through the troposphere before reaching the GNSS antenna. Various tropospheric models are being used to correct the tropospheric delay. In this study, we compared effectiveness of two popular troposphere correction models: Global Pressure and Temperature (GPT) and Satellite-Based Augmentation System (SBAS). One-year data from a particular site was chosen as the test case. Tropospheric delays were computed using the GPT and SBAS models and compared with the International GNSS Service tropospheric product. The bias of SBAS model computations was 3.4 cm, which is four times lower than that of the GPT model. The cause of higher biases observed in the GPT model is the fact that one cannot get wet delays from the model. If SBAS-based wet delays are added to the hydrostatic delays computed using the GPT model, then the accuracy is similar to that of the full SBAS model. From this study, one can conclude that it is better to use the SBAS model than to use the GPT model in the standard code-pseudorange data processing.
정관동(Kwan-Dong Jung),엄기영(Ki-Young Eum),최찬용(Chan-Yong Choi),조수익(Su-Ik Jo),황인환(Hwan-In Hwang) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7
The method in a bid to make better use of limited urban space amidst increasingly expanding urban area have been attempted in various ways. Efficient using underground space is one of the examples. The pipe roof and excavation for underground crossing implemented in this study was the part of evaluation of such attempt. However, the pipe roof method for underground crossing may cause the ground surface to be uplifted or settled down, having effect on structure above the ground. Thus in this study, a laboratory model test designed to evaluate the effect on surface during implementing pipe roof and excavation was carried out. The ground displacement during pipe roof advancing and excavation is usually occurred in a radial shape but as the study focused on trackbed, the evaluation included ground settlement only. Thus, appropriately-scaled model was selected considering domestic geological characteristics and operation characteristics of traditional and high-speed rail trains and the qualitative evaluation of displacement was carried out with a certain ground loss depending on excavation after categorizing trackbed settlement pattern depending on depth of top soil.