• 한국운동역학회지
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• 제16권1호
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• pp.119-128
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• 2006

This study was performed to see ground reaction force with different soccer studs with twelve players in Human Performance Laboratory(University of Calgary). Running speed was $4.0{\pm}0.2m/sec$ in straight running as well as vcut running. By using four different kinds of shoes; three different pairs of soccer shoes and one pair of jogging shoes, I reached a conclusion as following. In case of right and left ground reaction force, on the assumption that the positive magnitude of power is inversion and the negative is eversion, vcut running did not occur any inversion, which in the aspect of kinetic mechanics, thought to be decelerating movement. Because when eversion happens, it arises component force of power on heading direction about 8.6 times more than in the movement of straight running. In case of front and rear ground reaction, on the assumption that the positive magnitude of power is suspension power and the negative is propulsion, vcut movement is thought to be decelerating movement in the aspect of kinetic mechanics. Because on heading direction, this movement occurs component force of power about 1.8 times more suspension and 2.2 more propulsion than in the straight running movement. In case of vertical ground reaction, on the assumption that the first peak is the magnitude of power in impact and the second peak is the magnitude of power in active, we judged that the straight running movement performed more efficiently than the vcut movement in the aspect of kinetic mechanics. On the next study, I suppose that vcut running would make up an interesting subject in the aspect of improving kinetic performance ability.

• 한국가스학회지
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• 제24권4호
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• pp.32-38
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• 2020

화학반응기에 발생한 화재·폭발 사고사례를 기반으로 화학반응기에 설치되어 있는 예방조치의 문제점을 분석하였다. 화학반응기는 다품종의 화학제품을 생산하며, 반응폭주시 급격히 상승하는 압력을 해소하기 위해 파열판을 설치하고 파열판의 기능을 유지하기 위해 배출물질을 대기로 배출하도록 허용하고 있어 화재·폭발사고가 발생하였다. 이를 개선하기 위한 방안으로 안전건전성수준(SIL3)을 기반으로 한 안전계장시스템(SIS)을 화학반응기의 예방조치로 적용하였다. 화학반응기의 원재료를 적하하는 배관에 긴급차단밸브를 직렬로 2개 설치하여 반응폭주시 긴급차단밸브 2개 중 1개만 작동하여도 원재료 공급을 차단할 수 있도록 하고, 반응응제제 공급배관에는 자동 ON/OFF 밸브를 병렬로 설치하여 반응폭주시 1개의 밸브만 열려도 반응억제제가 투입될 수 있게 하였다.

• 공업화학
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• 제16권2호
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• pp.282-287
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• 2005

팔라듐 분리막은 수소에 대한 선택적 투과성능이 우수하여 수소의 분리 정제와 막반응기에 많이 이용된다. 무전해 도금법에 의해 팔라듐을 다공성 세라믹막 표면위에 도금하고 내구성을 향상하기 위한 후처리로서 사염화 티탄($TiCl_4$)을 이용한 에칭으로 팔라듐-세라믹 복합막을 제조하였다. 제조된 팔라듐-세라믹 복합막을 막반응기로 이용하여 수성가스전환반응에 적용하였으며, 여러 가지 실험 변수에 따른 CO 전환율을 조사하였다. 막반응기를 사용하지 않은 전통적인 반응기와 비교한 결과, 적정조건에서 막반응기의 CO의 반응전환율이 20~25% 이상 향상되었다. 막반응기에서의 수성가스반응은 120 h의 운전 결과, CO의 반응전환율이 변함없이 안정적으로 유지되었다.

• 한국환경과학회지
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• 제31권7호
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• pp.609-616
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• 2022

In this study, the effect of different reaction times for thermal-alkaline pretreatment on the solubilization and biogasification of polyhydroxybutyrate (PHB) were evaluated. Thermal-alkaline pretreatment tests were performed at 73 ℃ and pH 13 at 0-120 h reaction times. The mesophilic anaerobic batch tests were performed with untreated and pretreated PHB samples. The increase in the pretreatment reaction time results in a 52.8-98.8% increase of the abiotic solubilization efficiency of the PHB samples. The reaction time required to achieve solubilization efficiencies of 50%, 90%, and 95% were 10.5, 52.0, and 89.6 h, respectively. The biogasification of the untreated PHB samples achieved a specific methane production rate of 3.6 mL CH₄/g VSS/d and require 101.3 d for complete biogasification. The thermal-alkaline pretreatment significantly improved specific methane production rate (10.2-16.0 time increase), lag time (shortened by 76-81%), and time for complete biogasification (shortened by 21-83%) for the biogasification of the PHB samples when compared to those of the untreated PHB samples. The improvement was higher as the reaction time of the thermal-alkaline pretreatment increased. The findings of this study could be used as a valuable reference for the optimization of the biogasification process in the treatment of PHB wastes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.75-75
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• 2011

Recently, dye-sensitized solar cell (DSSC) attracts great attention as a promising alternative to conventional silicon solar cells. One of the key components for the DSSC would be the nanocrystalline TiO2 electrode, and the control of interface between TiO2 and TCO is a highly important issue in improving the photovoltaic conversion efficiency. In this work, we applied various interfacial layers, and analyzed their effect in enhancing photovoltaic properties. In overall, introduction of interfacial layers increased both the Voc and Jsc, since the back-reaction of electrons from TCO to electrolyte could be blocked. First, several metal oxides with different band gaps and positions were employed as interfacial layer. SnO2, TiO2, and ZrO2 nanoparticles in the size of 3-5 nm have been synthesized. Among them, the interfacial layer of SnO2, which has lower flat-band potential than that of TiO2, exhibited the best performance in increasing the photovoltaic efficiency of DSSC. Second, long-range ordered cubic mesoporous TiO2 films, prepared by using triblock copolymer-templated sol-gel method via evaporation-induced self-assembly (EISA) process, were utilized as an interfacial layer. Mesoporous TiO2 films seem to be one of the best interfacial layers, due to their additional effect, improving the adhesion to TCO and showing an anti-reflective effect. Third, we handled the issues related to the optimum thickness of interfacial layers. It was also found that in fabricating DSSC at low temperature, the role of interfacial layer turned out to be a lot more important. The self-assembled interfacial layer fabricated at room temperature leads to the efficient transport of photo-injected electrons from TiO2 to TCO, as well as blocking the back-reaction from TCO to I3-. As a result, fill factor (FF) was remarkably increased, as well as increase in Voc and Jsc.

• Korean Chemical Engineering Research
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• 제58권4호
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• pp.536-540
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• 2020

고분자연료전지(PEMFC) 고분자막의 지지체는 기계적 내구성 향상에 핵심적인 역할을 한다. 지지체로 사용하는 e-PTFE는 화학적으로 안정하여 PEMFC 구동과정에서 전기화학적인 열화에 대해서는 거의 연구되지 않았다. 본 연구에서는 e-PTFE가 Fenton 반응과정에서 발생한 라디칼과 과산화수소에 화학적으로 안정한지 검토하였다. Fenton 반응 과정에서 e-PTFE의 주사슬이 끊어져 지지체의 화학적 구조와 형태 변화가 발생하였고, 그에 따라 인장 강도가 감소하였다. 실제 PEMFC 구동과정에서 고분자막 이오노머의 전기화학적 열화는 라디칼과 과산화수소에 의해서 고분자막 내부에서 발생하므로, e-PTFE 지지체의 셀 내에서 전기화학적 열화도 발생할 수 있음을 본 연구 결과가 보였다.

• 대한기계학회논문집A
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• 제34권9호
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• pp.1217-1225
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• 2010

소듐을 냉각재로 사용하는 고속로의 증기발생기에서는 소듐과 물의 화학적 반응을 최소화하는 것이 중요한 문제이다. 소듐과 물의 반응 가능성을 줄여 증기발생기의 신뢰성을 향상시키기 위한 한가지 방안으로 이중벽관을 전열관으로 사용하는 증기발생기를 개발하고 있다. 이 증기발생기에서 중요한 현안은 이중벽관에서의 열전달 성능을 향상시키는 문제와 원자로 운전 중에 소듐과 물 반응사고가 일어나기 전에 전열관의 파손을 감지하는 기술을 개발하는 것이다. 이 논문에서는 이 현안을 극복할 수 있는 방안을 제시하였고, 이 기술을 활용하여 증기발생기의 개념을 설계하였다. 또한 이 개념에 적용되는 이중벽관을 설계 및 예비 제작하여 기계적 시험을 수행하였다.

• 대한환경공학회지
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• 제35권4호
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• pp.257-262
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• 2013

불산(HF)을 함유한 폐수는 주로 불소이온($F^-$)과 불화붕산염($BF{_4}{^-}$)을 포함하고 있으며, 불산 폐수처리는 보편적으로 칼슘을 이용한 응집 침전 공정을 사용하고 있다. 불소이온은 칼슘이온에 의해 높은 제거효율을 나타내지만 불화붕산염($BF{_4}{^-}$)의 경우 반응성이 낮아 총 불소 제거에 많은 어려움이 있다. 본 연구의 목적은 알루미늄을 이용하여 불화붕산염을 분해하여 총 불소 제거 효율을 향상 시키는데 있다. 불소처리공정 모사 반응기를 이용하여 pH, 알루미늄 주입량, 수온에 따른 불화붕산염의 분해 실험을 실시하였다. 실험결과 알루미늄을 이용한 불화붕산염 분해는 낮은 pH와 높은 수온 그리고 Al/T-F (Aluminum/Total Fluoride) mole ratio가 증가할수록 분해속도도 증가하였으며 반응시간 120분 후에는 큰 농도변화가 없는 것으로 나타났다. 연구결과 알루미늄을 이용한 처리를 통하여 불화붕산염을 포함한 폐수의 처리효율을 향상시킬 수 있을 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.107-109
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• 2004

In this paper, authors propose the sensor fusion system that can recognize multiple 3D objects from 2D projection images and tactile information. The proposed system focuses on improving recognition performance of 3D object. Unlike the conventional object recognition system that uses image sensor alone, the proposed method uses tactual sensors in addition to visual sensor. Neural network is used to fuse these informations. Tactual signals are obtained from the reaction force by the pressure sensors at the fingertips when unknown objects are grasped by four-fingered robot hand. The experiment evaluates the recognition rate and the number of teaming iterations of various objects. The merits of the proposed systems are not only the high performance of the learning ability but also the reliability of the system with tactual information for recognizing various objects even though visual information has a defect. The experimental results show that the proposed system can improve recognition rate and reduce learning time. These results verify the effectiveness of the proposed sensor fusion system as recognition scheme of 3D object.

• The Journal of Korean Physical Therapy
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• 제27권3호
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• pp.129-134
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• 2015

Purpose: The purpose of this study was to determine the influence of WBV exercise on CMJ and quadriceps muscle activation according to different frequency of vibration in soccer player and also to find effective frequency for leading appropriate treatment reaction. Methods: Thirty three subjects were randomly divided into three groups: the three groups are WBV group using 20 Hz frequency, WBV group using 30 Hz frequency and squat exercise group according to training method. The exercise program was conducted for six weeks. Subjects were measured on CMJ and quadriceps muscle activation. Results: Significant difference in CMJ was observed in the group I, II compared with the group III (p<0.05). Results of post-hoc, showed a significant difference in CMJ in on group I, II compared with the group III, but no a statistically significant difference between group I and II. Significant difference in quadriceps muscle activation was observed in the group I, II compared with the group III (p<0.05, p<0.01). Results of post-hoc, significant difference in quadriceps muscle activation in on group I, II compared with the group III and significant difference between group I and group II. Conclusion: This research intervened WBV for soccer players and compared the differences of CMJ and quadriceps muscle activation; as a result of the effective frequency for improving performance, there is a significant difference in CMJ and quadriceps muscle activation of WBV group with comparison of control group; and it was proved that WBV is effective using 30 Hz frequency for improving quadriceps muscle activation.