• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.229-234
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• 2004

A Typhoon wave is generated by wind fields during the Passage of Typhoon. Transporting wind field makes wind wave and swell in the open sea, and then, those wave components are transported in the shallow water. Typhoon waves in the shallow water is generated by Typhoon wind field and incident wave. Bisides, Incident waves to the shallow water are deformated by topographic conditions. This paper estimated the analysis of the Typhoon waves by wind fields and incident waves according to wave action balance equation model. As the result of wave numerical experiment, wave field during the passage of Typhoon 'Memi' in the shallow water is strongly effect by wind fields. Wave action balance equaion can be partially used for Typhoon wave simulations.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.25-30
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• 1993

The buds of Hayward/Bruno tree were damaged from $-7^{\circ}C$ but serious damage was found on the buds treated at $-15^{\circ}C$ and $19^{\circ}C$. The bark tissue was more suceptible to low temperature than the bud. The trees were survived and bursted their at all on the top of the graft union and new shoots were formed from the rootstock of the tree. Yellowish area on the leaf surface was found, which is believed that as a result of low temperature. From these, the kiwifruit trees must be grafted with cold tolerant rootstocks will be clarified in future.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.520-538
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• 2019

In this study, it was proposed that a method of setting the target water quality for TOC using the watershed model and the load duration curves to manage non-biodegradable organics in the total water load management system. To simulate runoff and water quality of the watershed, the HSPF model is used which is appropriate for urban and rural areas. Additionally, the load duration curve is used to reflect the variable water quality correlated with various river flow rates in preparing the TMDL plans in the U.S. First, the model was constructed by inputting the loads calculated from the pollutant sources in 2015. After the calibration and verification process, the water quality by flow conditions was analyzed from the BOD and TOC simulation results. When the BOD achieved the target water quality by inputting the target year loads for 2020, the median and average values of TOC were proposed for the target water quality. The provisional method of TOC target water quality for the management of non-biodegradable organics, which is one of the challenges of the total water load management system, was considered. In the future, it is expected to be used as basic data for the conversion of BOD into TOC in the total water load management system.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.25-31
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• 2003

Numerical experiments have been conducted using the nonlinear combined refraction-diffraction model, in order to analyze the generation characteristics of stem wave, which is formed by the interaction between vertical structure and the oblique incident waves. The results of stem wave are discussed through the stem wave height distribution along/normal vertical structure, under the wide range of incident wave conditions-wave heights, periods, depths, and angles. Under the same wave height and period, the larger the incident wave angle, the higher the stem wave heights. According to the results of wave height distribution, in front of vertical structure, the maximum of stern wave heights occurs in the location bordering the vertical wall. Furthermore, the most significant result is that stem waves occur under the incident angles between $0^{\circ}\;and\;30^{\circ}$, and the stem wave height ratio has the maximum value, which is approximately 1.85 times the incident wave height when the incident wave angle becomes $23^{\circ}$.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.277-283
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• 2003

This paper constructed the 3D real-time numerical model for which predicts the water quality and movement characteristics of the inner bay, which consider the characteristics of the wind-driven current and density current in estuaries which generated by the river discharge from the Hyeong-san river and oceanic water of the Eastern sea. The constructed numerical model reappeared successfully the seawater circulation current of Yeong-il Bay, which used the input conditions of the real-time tidal current, river discharge and weather conditions at March of 2001 year. Also to observe the wind-driven current and density current in estuaries effected to the seawater circulation pattern of the inner bay, we investigated the analyzation for the each impact factors and the relationship with the water quality of Yeong-il bay

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.303-308
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• 2003

In this paper, wave numerical modeling was experimented for the analysis of impact factors for the wave transmission as the incident wave and topographic conditions in the narrow channel sea. Recently, Although the results of many researcher for the wave modelling, numerical equations have limited to simulation of wave transformation effects. Despite of thispresent problems, the models was used to design the coastal structures in barrow channel sites. Finally, this paper estimated the wave model(mild slope eq. model) as the analysis of the wave energy transmission according to changing of impact factors(width of channel, bottom slope in channel, incident wave angle, wave period). As the results of numerical experiment, the major impact factors which influence to wave energy transmission were the width of channel and incident wave direction. But in the case that the width of channel is larger than 3L(L=Length of wave), the reduction of wave energy was small.

• Korean Journal of Materials Research
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• v.6 no.5
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• pp.504-514
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• 1996

고상반응법과 sol-gel법으로 제조된 NASICON의 상온과 25$0^{\circ}C$에서의 X선 회절 데이터를 리트벨트 분석을 행하였다. monoclinic에서 rhombohedral로 상전이가 일어나도 원자들의 변위는 매우 작았다. 이들 상간의 ZrO6 팔면체와 Si(P)O4 사면체고 구성된 골격은 다소 다르게 나타남으로 인하여 Na 이온의 자리도 변하였다. 이들 방법으로 제조된 NASICON은 Zr이 부족한 비화학양론 화학식, Na 1+x+4yZr2-xSixP3-xO12으로 표현될 수 있었다. 제조법에 따라 Na 이온들의 자리 점유율이 변화하였다. 상온에서는 Na(1)과 Na(3)자리의 자리 점유율의 합이 거의 1에 가까웠으나, 25$0^{\circ}C$에서는 Na(1)과 mid Na 자리를 단위 화학식 당 한 개를 약간 상회하는 Na 이온이 점유하였다. 상온과 25$0^{\circ}C$에서의 Na 이온의 이동 경로가 다름을 알 수 있었다. 또한 25$0^{\circ}C$에서는 Na(1)자리와 Na(2)자리 사이에 mid Na가 존재하며, 이 자리가 Na 이온의 이동에 중요한 역할을 함을 알 수 있었다.

• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.723-727
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• 2004

Three kinds of $Si_3N_4$ powders (M-11, SN-ESP, and SN-E10) were gas-pressure sintered at $1700-1900^{\circ}C$ for 2 h under 18 atm $N_2$. Their densification behavior was investigated and compared as well as the mechanical properties and microstructure of the resulting ceramics. SN-ESP and SN-E10 started to reach nearly full densification at $1750^{\circ}C$ and showed almost no decomposition up to $1900^{\circ}C$. In contrast, M-11 was not fully densified until $1800^{\circ}C$ and showed about $3\%$ weigh loss at $1900^{\circ}C$ indicating poor thermal stability. SN-ESP and SN-E10 showed much higher strength both at room temperature and $1200^{\circ}C$ than M-11 when fully densified. Compared with SN-ESP, SN-E10 was not only a little better in strength (both at room temperature and $1200^{\circ}C$) and fracture toughness but also much higher in the Weibull modulus due to more interlocked microstructure by well elongated grains.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1095-1100
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• 2013

Piezo devices have large power density and simple structure compared with conventional electrical motors. Thus they can generate larger forces than the conventional actuators with small size. Their resopnses to commands are also very fast and thus the bandwidths are very wide. Thus the piezo devices are expected to be used widely in the future for actuating devices requiring fast response and large actuating force with small size. However, the piezo actuators need high voltage with high driving current due to their large capacitive property. In this paper, proposed is a simple method to drive piezo devices using voltage inversion circuit with coli inductance. The coil inductance carries the charges in the piezo device to the opposite side, inverting the polarity of the applied voltage, thus saving the power to drive the device with AC voltages. Experiments with real circuit demonstrates that the proposed scheme can improve the energy efficiency very much.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.8-13
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• 1985

Egremont russet 사과 품종(品種)의 종자에 여러가지 종피(種皮) 파상(破傷)을 한 후 발아(發芽), 유아(幼芽), 유근(幼根)의 생장(生長)과 생리적(生理的)인 왜화(矮花)에 대(對)하여 조사한 결과 다음과 같은 결과를 얻었다. 자엽(子葉)의 크기를 1/2로 절단하고 종피(種皮)를 제거(除去)한 Egremont russet 사과 품종(品種)의 종자(種子)에 $GA_3$를 처리한 것은 평균발아율(平均發芽率)이 55%였으며 동일조건(同一條件)에서 대조구(對照區)는 45%였다. 그리고 종피(種皮)가 완전(完全)한 것과 종피파상(種皮破傷)을 한 구(區)에서는 낮았다. 유아장(幼芽長)은 종피(種皮)를 완전히 남긴 것과 파상(破傷)한 구(區)에 $GA_3$를 처리하였을 때 촉진(促進)되었으나 전체적(全體的)으로 볼 때 종피(種皮)를 제거(除去)한 구(區)에서 더 길었다. 그러나 유근장(幼根長)은 $GA_3$처리에 의(依)해서 억제(抑制)되었으나 유근(幼根)의 직경(直徑)은 더 커졌다. 그리고 생리적(生理的)인 왜화(矮花)는 종피(種皮)를 남긴 구(區)에서 발생(發生)되었으며 $GA_3$ 처리에 의(依)해 극복되지 않았다. 자엽(子葉)의 녹색화(綠色化) 속도는 종피(種皮)를 제거(除去)하고 자엽(子葉)의 크기를 1/2로 절단한 구(區)에서 촉진(促進)되었다.