• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1951-1955
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• 2010

우량관측용으로 사용되고 있는 강우량계는 전도형, 저수형, 로드셀형, 중량식 등이 있으며 이 중 측정과 신호의 처리가 간편한 전도형 우량계가 널리 사용되고 있다. 우량관측은 목적에 따라 기상청은 0.5 mm 급 전도형 우량계를 주로 사용하고 있으며, 국토해양부에서는 1 mm 급 전도형 우량계를 주로 사용하고 있다. 본 연구에서는 강우량 증가 및 강우강도에 따른 0.5 mm 및 1 mm 급 전도형 우량계의 측정값을 분석하여 실제값과 얼마의 오차를 보이는지 그 특성을 비교 분석하였다. 이 실험은 수문조사기기 검정대행기관인 유량조사사업단에서 우량계 검정에 사용하고 있는 강우량 검정용 기준기를 이용하여 10~20 mm 강우량 및 20~100 mm/h의 강우강도 변화에 따라 0.5 mm 및 1 mm 급 전도형 우량계의 측정값을 비교하여 각 우량계에 대한 특성을 분석하였다. 본 연구는 향후 실제 강우에 대한 같은 특성 분석 연구를 통해 이 결과를 확인 및 보완하는 연구를 진행할 예정이다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1801-1802
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• 2006

강우량계는 기상관측 장비중 비가 온 양을 측정하기 위한 장비로 전도형, 저수형, 중량형, 로드셀형 등 다양한 종류의 강우량계가 있다. 전도형 우량계의 경우 단순한 측정방법 및 유지보수의 용이성, 접점방식에 의한 신호의 디지털화 적용성이 우수하기 때문에 가장 널리 사용되고 있다. 전도형 우량계는 분해능에 따라 0.1mm, 0.2mm, 0.5mm, 그리고 1.0mm급으로 분류며, 저수지 관리를 위해 사용되고 있는 우량계는 1.0mm 급을 주로 사용하고 있으며, 보다 정밀하게 측정하기 위하여 0.5mm 급 우량계도 사용하고 있다. 이러한 전도형 우량계의 정확도를 검정하기 위한 방법으로 수자원연구원에 질량측정에 의한 검 교정을 할 수 있는 표준교정시스템이 구축되어 있으며, 이 시스템을 이용하여 0.5mm 및 1.0mm 전도형 우량계에 대하여 강우강도를 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 mm/h로 가변하면서 강우강도의 변화에 따른 분해능이 다른 우량계의 오차특성을 비교 분석하고자 한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.302-303
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• 2007

수문관측용으로 사용되는 강우량계는 측정의 편의성과 강인성의 장점 때문에 대부분 전도형 우량계를 사용하고 있다. 한국수자원공사에서는 약 160여개의 우량국을 관리하고 있으며, 2006년도 교정주기가 도래한 우량계 16개 및 특성 분석이 필요한 우량계 4개 등 총 20개에 대하여 한국수자원공사 수자원연구원에서 개발한 전도형 우량계 표준교정시스템을 이용하여 교정을 실시하였다. 우량계의 교정결과 버켓의 평균값이 기준값 1 mm에 대하여 0.95$\sim$1.04mm까지 다양하게 측정되었으나, 모두 기준인 $\pm$5 %를 만족하는 것으로 나타났으며, 전도형 우량계는 강우강도가 강할수록 측정되는 강우량이 많아지는 특성을 확인할 수 있었다.

• Explosives and Blasting
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• v.26 no.1
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• pp.7-14
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• 2008

In order to complete successfully the demolition of a silo structure by means of felling method, structural properties and the geometric design of blast mouth have to be considered. In this study, a commercial software, 3-dimensional applied element analysis (3D AEM), was used to investigate the effect of the geometrical parameters of blast mouth on the collapse behavior of the silo structure.

• Explosives and Blasting
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• v.26 no.2
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• pp.52-63
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• 2008

Recently the demand of demolition for the unnecessary cylindrical silo structure is increasing due to deterioration and unsatisfactory functional conditions and the issue of demolition is becoming a major highlight. This case study introduced the explosive demolition of the cylindrical silo structure by felling method. The results of explosive demolition conducted on cylindrical silo structure using the felling method show, A silo had collapsed precisely according to estimated direction but in case of B silo there was a minor difference. The lower colunms and ring girder support was designed to the hinge line but in reality the lower colunms of the silo did not do its structural support role and only the ring girder support did its role successfully. As for the impact vibration, most of the measurements were within the estimated range.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.5
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• pp.1-12
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• 2023

This study evaluated the overturning stability of portable tripod ladders used for high-altitude work such as tree management and pruning work in landscaping construction and management. Portable tripod ladders, which are included in general mobile or portable ladders frequently used in industrial sites, are supported in a triangular support structure, not a 4-point support like common A-type Ladders. In addition, since the working height is more than twice that of a mobile or portable ladder, the possibility of an overturning accident that threatens the safety of workers with a fall accident is high. Therefore, based on the overturning stability test specified in ANSI-ASC A14.7 and EN 131-Part 7, which are related standards for about 130 types of portable tripod ladders sold and used in Korea. An equation to calculate each moment according to working height was derived. Then, each calculated moment was compared to evaluate the safety factor for overturning and stability. As a result of the overturning stability evaluation according to each standard, when the provisions of EN 131-Part 7 were applied, portable tripod ladders with 8 steps in the rear direction and 6 steps or more in the side direction were evaluated as unstable against overturning, but according to ANSI-ASC A14.7 regulations. It was evaluated that the stability against overturning was secured in all directions and number of steps.

• Polymer(Korea)
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• v.27 no.3
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• pp.201-209
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• 2003

DC and AC electrical conductivity and electromagnetic interference shielding effectiveness of milled carbon fiber/nylon composites were investigated with the kind of nylon matrix. Percolation transition at which the conductivity is sharply increased was observed at about 7 vol% of milled carbon fiber. Nylon 46 as a matrix was more effective to obtain high electrical conductivity than nylon 6, and the difference in conductivity was occurred by the treatment of coupling agent. Frequency dependence of AC conductivity could be explained by relaxation phenomenon at just below percolation and resonance phenomenon at 40 vol% of carbon fiber, respectively. Negative temperature coefficient phenomenon was found in all composites. Electromagnetic interference shielding effectiveness was increased with the concentration of carbon fiber. At a high conductivity region the return loss was more dominant to the total shielding effectiveness than the absorption loss.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.211-217
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• 2004

The instrument used in this study consists of a lkg capacity loadcell and a Imm tipping bucket rain gauge. There are two signals: one is the weight of the water in the tipping bucket and the other is the pulse from the reversing mechanism of the tipping bucket. The loadcell measures the weight of water with a 0.0lmm resolution up to 1mm rainfall and the bucket reverses beyond 1mm. From this point, a pulse signal generates and the loadcell starts measuring the weight again. A field test was carried out with the range of rainfall intensity from 42mm/h to 250mm/h. The result shows an error range from -2.2% to + 2.6% in 12 measurement cases with a rainfall of l00mm or more. This result satisfies the WMO recommendation for rainfall intensity instrumentation which allows a 5% range. In a field experiment during 17 to 19 August, 2004, more than 100mm/h rainfall intensity was observed by this instrument, confirming that our instrument has a sufficient capacity of rainfall intensity measurement under extreme conditions like Jangma (Bai-u season). Compared with existing commercial models which employ a water drop measurement method, our method can give a practical solution for diagnostic check of remote rain gauges using two independent signals.

• 전기의세계
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• v.9
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• pp.40-45
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• 1962

Laplace 및 Possion의 방정식을 만족하는 전장 및 자장으로 구성된 2차원 및 축대칭 3차원의 potential장을 물의 유동장을 이용한 fluid mapper로 상사해석함에 있어서 세극유로에 있어서의 유체전도율은 매질전도율로 압력은 전위로 유동장의 세기는 전장의 세기로, 유량밀도는 전류밀도로 각각 상사되며 또한 사상형에 있어서는 사상영역외에 존재하는 유선은 등자위선을 의미함을 논문에서 밝혔다. 이 논문에서는 사상형 fluid mapper의 전 유로 및 사상영역에 잇어서의 유체력학적 현상을 이론적으로 규명하여 이를 전기적 등가회로와 상사 해석함으로써 사상형 fluid mapper가 내포하고 있는 제량간의 상호관계를 명백히 하며 몇 가지 대표적인 사례를 들어 사상형 fluid mapper의 응용에 대하여 기술하였다.

• Analytical Science and Technology
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• v.5 no.1
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• pp.79-82
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• 1992

A bipolar pulse conductometric detector has been developed for continuous on-line monitroring of the flowing sample streams. The conductometric detector was fast and easy to use due to the free of interferences by serial or parallel capacitances. The performance of the bipolar pulse conductometric detector was tested using dummy cells with $10^1{\sim}10^8$ ohm resistance range and found a linear response with a 0.01% relative standard deviation. The possible applications of the bipolar pulse conductometric detector was discussed.