• 한국구조물진단유지관리공학회 논문집
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• 제8권4호
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• pp.165-174
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• 2004

본 연구에서는 고속철도 ${\bigcirc}{\bigcirc}$역사 공사구간 중 굴착구간에 인접하여 하천이 위치하고 공사구간 좌측에는 항상 만수위 상태의 저수지가 있어 지반 굴착시 지하 5m 깊이에서 지하수위가 존재하는 구간에 설치된 부력앵커의 수평재하시험에 관한 연구이다. 따라서 본 연구에서는 지하수위 면이 발생하는 구간에 설치된 부력앵커의 현장 수평재하시험을 통해 영구적으로 지하수위에 의해 부력을 받는 구조물의 장기적인 안정성을 평가하고자 한다. 이를 위해 고강도 강봉이나 강연선을 사용, 지반과의 마찰력을 이용하여 부력에 저항하는 방법으로 충분한 인발력을 확보할 수 있는 Bar Type 앵커를 사용하였다. 고속철도의 제동과 가속에 의해 수평력을 받는 지하구조물 바닥 슬래브에 부력방지용 앵커를 설치하였다. 이로 인해 Bar Type 부력앵커에 발생되는 거동특성을 파악하기 위해 수평재하시험을 실시하여 고속철도의 주, 정차시 열차의 급제동및 출발에 의해 발생되는 수평력에 대한 부력앵커의 거동특성을 파악하고자 하였다.

• 대한수학회보
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• 제57권3호
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• pp.649-660
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• 2020

This paper proves a new regularity criterion for solutions to the Cauchy problem of the 3D Boussinesq equations via one directional derivative of the horizontal component of the velocity field (i.e., (∂_iu₁; ∂_ju₂; 0) where i, j ∈ {1, 2, 3}) in the framework of the anisotropic Lebesgue spaces. More precisely, for 0 < T < ∞, if $$\large{\normalsize\displaystyle\smashmargin{2}{\int\nolimits_o}^T}({\HUGE\left\|{\small{\parallel}{\partial}_iu_1(t){\parallel}_{L^{\alpha}_{x_i}}}\right\|}{\small^{\gamma}_{L^{\beta}_{x_{\hat{i}}x_{\bar{i}}}}+}{\HUGE\left\|{\small{\parallel}{\partial}_iu_2(t){\parallel}_{L^{\alpha}_{x_j}}}\right\|}{\small^{\gamma}_{L^{\beta}_{x_{\hat{i}}x_{\bar{i}}}}})dt<{{\infty}},$$ where ${\frac{2}{{\gamma}}}+{\frac{1}{{\alpha}}}+{\frac{2}{{\beta}}}=m{\in}[1,{\frac{3}{2}})$ and ${\frac{3}{m}}{\leq}{\alpha}{\leq}{\beta}<{\frac{1}{m-1}}$, then the corresponding solution (u, θ) to the 3D Boussinesq equations is regular on [0, T]. Here, (i, ${\hat{i}}$, ${\tilde{i}}$) and (j, ${\hat{j}}$, ${\tilde{j}}$) belong to the permutation group on the set 𝕊₃ := {1, 2, 3}. This result reveals that the horizontal component of the velocity field plays a dominant role in regularity theory of the Boussinesq equations.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.37-43
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• 2004

A measurement accuracy of theodolite system may be affected by a measurement environment, a measurement distance change and so on. This study was performed for measuring an accuracy when the height of scale bar is changed 0.05m, 0.5m, 1m and 1.5m under the distance 3m between two theodolites, the distance 4m from the theodolite system to scale bar and the distance 5m from the thodolite system to the horizontal target bar. And we could know that the best height is 0.05m and 1m.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1130-1134
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• 2005

To monitor the possibility of horizontal gene transfer between transgenic potato and bacteria in the environment, the gene flow from glufosinate-tolerant potato to bacteria in soils was investigated. The soil samples treated with the leaf tissue of either glufosinate-tolerant or glufosinate-sensitive potato were subjected to PCR and Southern hybridization to determine possible occurrence of glufosinate-resistant soil bacteria and to detect the bar (phosphinothricin acetyltransferase) gene, conferring tolerance to glufosinate. The bar gene was not detected from genomic DNAs extracted at different time intervals from the soil samples, which had been treated with the leaf tissue of either transgenic or non-transgenic potato for 2 to 8 weeks. In addition, the level of glufosinate-resistant bacteria isolated from the soil samples treated with the leaf tissue of transgenic potato was similar to that of the samples treated with non-transgenic potato after 4 months of incubation at $25^{\circ}C$. The bar gene was not detected in the genomic DNAs extracted from colonies growing on the plate containing glufosinate, indicating that the bacteria could acquire the resistant phenotype to glufosinate by another mechanism without the uptake of the bar gene from glufosinate-tolerant potato.

• 대한기계학회논문집
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• 제9권4호
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• pp.414-420
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• 1985

본 연구에서 상변화 물질은 얼음과 물을 택하였으며, 시편의 기하학적 형상은 원동형 얼음봉을 사용하였고 온도가 일정한 물속에 수평으로 잠겨진 상태에서 얼음봉 이 융해되는 현상을 가시화하고 이를 관찰하였다. 시편주위에 발생하는 자연대류현 상이 접면효과를 받지 않토록 하기 위하여 물탱크의 크기는 시편직경의 5배 이상으로 하였고 주위물의 온도는 정도가 최대인 4.deg. C 부근을 전후한 최저 2.5.deg. C에서 최고 15.deg. C 까지를 택하였다. 융해현상은 2차원 음영방법으로 가시화하고 사진으로 기록하였다. 융해되는 얼음봉의 형상은 Fourier수와 Stefan수의 곱으로 정의된 무차원시간(.zeta.)을 변수로 하여 나타내었다. 정해진 물의 온도에서 사진으로 기록된 결과를 콤퍼레이터 (comparator)를 이용하여 음영의 변화량을 구하여 각 원주각에서의 국부 Nusselt수와 평균 Nusselt수를 무차원시간에 대하여 구하였다.

• Journal of the Korean Wood Science and Technology
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• 제39권4호
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• pp.318-325
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• 2011

현장에서 시공성이 용이함과 동시에 강도 성능이 뛰어난 steel bar를 이용한 리기다소나무 옹벽을 제작하여 내력평가를 실시하였다. Steel bar를 이용한 목재옹벽은 횡목 4단과 종목 3단으로 적층하였으며, 높이 770 mm, 길이 2,890 mm, 폭 782 mm로 제작하였다. 적층 방법은 18 mm로 선공한 최상단과 최하단 횡목을 Steel bar에 삽입하며, 깊이 64 mm, 폭 18 mm의 슬릿을 낸 나머지 횡목과 종목을 Steel bar에 끼워 넣어 적층하였다. 완성 된 옹벽은 수평 재하 시험을 통한 내력 평가와 화상처리(AlCON 3D OPA-PRO system)를 통하여 구조물의 변형을 측정하였다. Steel bar옹벽에는 1개의 긴 횡목과 2개의 종목으로 구성된 접합부(Type-A)와 반턱으로 이음된 2개의 짧은 횡목이 2개의 종목으로 구성된 접합부(Type-B)가 공존하며, 이들을 각각 3개씩 제작하여 접합부의 압축형 전단내력 평가를 실시하였다. Steel bar옹벽의 수평 재하 시험결과 정각재 목재옹벽(박준철 등, 2010)보다 1.6배 이상의 강도를 나타냈으며, 이때 목재와 접합부의 파단은 발생하지 않았다. 접합부의 압축형 전단 내력 실험결과 Type-A의 평균 최대 하중은 130.13 kN, Type-B의 평균 최대 하중은 130.6 kN으로 측정되었다. 실험 결과 Steel bar를 이용한 목재옹벽은 정각재 목재옹벽보다 시공성이 우수하며 강도 또한 높게 측정되었다.

• 제어로봇시스템학회논문지
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• 제12권4호
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• pp.358-363
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• 2006

This paper demonstrates a new non-contact electronic joystick using single hall sensor which detects a horizontal vector of the magnetic field. Furthermore, in this paper, it is mathematically modeled that nonlinear characteristics between the output of hall sensor and the movement of joystick bar. The dynamic horizontal vector of magnetic flux is detected by the hall sensor while a permanent magnet is rotated with the joystick bar, which has two dimension detecting area. Using the nonlinear adjustment equations, the output signals of hall sensor have been linearized to give higher accuracy in the two dimension movement. Finally, through the real experiments, it is showed that the single hall sensor structure mechanism is superior to the dual sensor structure in sensing the two-dimensional motion without offset.

• 한국주조공학회지
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• 제16권2호
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• pp.116-123
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• 1996

The equipment for the horizontal continuous casting was built to produce hyper-eutectic Al-Si bars with a small cross-section of 25mm in diameter. The manufacturing processes including withdrawal cycle and secondary cooling methods were modified to refine the primary and the eutectic Si. The longitudinal casting speeds varied over the ranges of 670-1100mm/min for pure Al, and 200-350mm/min for Al-17wt%Si alloy. Due to the difference of cooling rate in the mould, microstructural asymmetry between the lower and the upper part of bar was observed. Thus, manufacturing processes such as cooling and withdrawal method were optimally combinated to get the homogeneous cast structure. With the increase of casting speed, the primary Si size was refined down to $30{\mu}m$ near the surface, and $80{\mu}m$ in the center of the bar.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.129-132
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• 2006

This paper is to investigate passing performance of high performance concrete between reinforcing bar depending on maximum size of coarse aggregates. Increase in maximum size of coarse results in decrease in water demand and sand to aggregate to secure target slump flow. The larger the maximum size of coarse aggregates is, the denser the space between reinforcing bar is, the amount of concrete passed through the reinforcing bar cage shows to decrease. HPC has favorable passing performance, regardless of aggregate size, when only vertical reinforcing bar is arranged. Whereas, when vertical and horizontal reinforcing bar is arranged at the same time, proper space between reinforcing bar is considered larger than 32mm in case of using 20mm coarse aggregate, 38mm in case of using 25mm aggregate. The increase in maximum size of coarse aggregate leads to increase compressive strength slightly. Length change shows to be decreased with the increase in maximum size of coarse aggregate.

• 한국운동역학회지
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• 제13권1호
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• pp.51-62
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• 2003

This study was attempted to kinematical characteristics of the El-grip swing with 1turn to el-grip in elite horizontal bar for the purpose of improving performance. The subjects were three males who were 2002 Busan Asian Games in men's team. The three dimensional motion analysis with DLT method was executed using three video cameras of analyzing the actual competition situation. In point of analyzing the actual competition situation, it is expected that gymnastics and coaches have the effective informations, and the following conclusion had resulted. 1. In case of release, It is impotant to make fast horizontal velocity of CM, high vertical position of CM, large hip and shoulder angle. Also It should be performed release motion of trunk rotation angle(+). 2. During LHR the action should be made at higher position than the CM and the shoulder joint is moving within $127{\pm}16.82$. It is important to make large lunk rotation angle. 3. During Hop, the RHR motion should be done in high position with short time and fast twisting action and to reduce the vertical speed is important.