株式指數先物의 國內導入에 따른 去來對象 指數開發애 관한 硏究

윤병길 서울大學校 大學院 1994 국내석사

Lemna gibba G3 잎 표피하세포의 세포막전위에 관한 고찰

윤병길 서강대학교 1985 국내석사

現行 法人稅法上 減價償却制度의 問題點 改善方案에 關한 硏究

윤병길 慶南大學校 1989 국내석사

압전 및 마찰전기를 이용한 에너지 수확

윤병길 인하대학교 대학원 2016 국내박사

Energy harvesting technologies, which are environmental friendly and renewable, have attracted a great deal of attention due to pollution and fossil fuels depletion. Among them, energy harvesting device using triboelectric or piezoelectric effect can generate power by vibration, which is abundant, ubiquitous, and more accessible than solar and thermal energy. With the advent of the Internet of things (IoT), the electric power supply for Wireless Sensor Network (WSN) Module may be highly significant. The alternative to battery is an energy harvesting device. For combining IoT and energy harvesting technology, there is a need to reduce power consumption of WSN Module and enhance power generation of energy harvesting device. In this thesis, I fabricated energy harvesting device using piezo-/tribo-electric effect and measured various properties, such as open-circuit voltage, closed-circuit current of devices, piezoelectricity or chemical bonding, etc., and studied origin of power generation of devices based on piezo-/triboelectricity. In chapter 2, a study for energy harvesting device based on lead-free single crystalline LiNbO3 nanowires was presented. In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50 μm in length) single-crystalline LiNbO3 nanowires having a high piezoelectric coefficient (d33 approximately 25 pm V-1). By blending LiNbO3 nanowires with poly(dimethylsiloxane) (PDMS) polymer (volume ratio 1:100), we fabricated a flexible nanocomposite nanogenerator having a low dielectric constant (approximately 2.7). The nanogenerator generated stable electric power, even under excessive strain conditions (approximately 105 cycles). The different piezoelectric coefficients of d33 and d31 for LiNbO3 may have resulted in generated voltage and current for the e33 geometry that were 20 and 100 times larger than those for the e31 geometry, respectively. This study suggests the importance of the blending ratio and strain geometry for higher output-power generation in a piezoelectric nanocomposite-based nanogenerator. In chapter 3, a study for enhanced triboelectric energy harvesting performance in surface-treated polydimethylsiloxane (PDMS) was presented. Due to its flexibility, transparency, easy fabrication, and high negative polarity, polydimethylsiloxane (PDMS) has been considered as one of the most appropriate materials for the use in triboelectricnanogenerator (TENG) applications. Here, we report the significantly enhanced triboelectric surface charge of PDMS simply by sprinkling of NaOH solution. Fresh PDMS-based TENGs generated an open-circuit voltage of 3.8 V and a closed-circuit current of 65 nA after the contact/separation from an indium tin oxide (ITO) electrode. After sprinkling the PDMS surface with 1 M NaOH, in contrast, the resulting TENG generated voltage of 10.4 V and current of 179 nA. Exposing the PDMS to ultraviolet-ozone prior to sprinkling with NaOH solution resulted in a triboelectric voltage and current of 49.3 V and 1.16 μA, respectively, which are almost 15-fold larger than those of fresh PDMS. The origin of the enhanced triboelectric charge is related with an increase of polar Si single bond O bonds at the expense of non-polar Si–CH3 bonds in PDMS. This work demonstrates a cost-effective method for producing large-area and high-efficiency PDMS-based TENGs and helps clarify the triboelectric mechanism of PDMS.

음성지시에 따른 전통적 심폐소생술과 가슴압박소생술시 흉부압박 정확도와 피로도 비교.

윤병길 충주대학교 일반대학원 2012 국내석사

본 연구는 전통적 심폐소생술과 가슴압박소생술의 정확도와 피로도를 비교하기 위한 연구이다 연구목적 : 심폐소생술 교육을 받은 일반인이 흉부압박만 실시하는 가슴압박소생술(Hands- Only CPR : HOCPR)과 흉부압박과 인공호흡을 하는 전통적 심폐소생술(Treditional CPR : TCPR)을 수행 시 정확도와 피로도를 비교 분석하여 일반인을 위한 전화상담 시 지침 마련을 위한 기초자료를 제공하고자 한다. 연구방법 : 응급의료정보센터를 통하여 4시간이내의 심폐소생술 교육을 받은 후 6개월 이상 지난 일반인을 대상으로 하여, HOCPR 수행 군(52명), TCPR 수행 군(48명)을 2분간 시행하였다. 2010 미국심장협회 지침을 기준으로 흉부압박의 깊이, 흉부압박의 속도, 흉부압박의 위치로 흉부압박의 정확도를 측정하였고, 실험 전․후 심장 박동수 변화, 산소포화도 변화로 생리적 피로도를 측정하였으며, 주관적 피로도는 설문을 통하여 측정하였다. 연구결과 : 흉부압박의 정확도은 평균깊이와 흉부압박깊이의 정확도, 흉부압박위치의 정확도에서 가슴압박소생술 수행 군이 전통적 심폐소생술 수행군보다 높은 점수를 보였으나 유의한 차이는 없었다. 하지만 평균속도와 흉부압박 속도의 정확도에서는 가슴압박소생술 수행 군이 전통적 심폐소생술 수행군보다 유의하게 높게 나타났다. 생리적 피로도를 측정하기 위한 시행 전․후 심장박동수 변화와 산소포화도 변화에서 HOCPR 수행 군이 더 낮은 변화를 보였으나 유의한 차이는 없었으며, 주관적 피로도는 두 군 간에 유의한 차이를 보여 HOCPR 수행 군에서 주관적 피로를 덜 느끼는 것으로 나타났다. 결론 : 심폐소생술 교육을 받은 경험이 있는 일반인을 대상으로 시행한 가슴압박소생술과 전통적 심폐소생술의 흉부압박 정확도와 피로도를 비교한 결과 가슴압박소생술을 실시한 군에서 더 정확하게 압박하고, 피로도도 더 낮게 느끼는 것으로 나타났다. 이에 심폐소생술 음성지도 시 교육을 받은 일반인에게도 가슴압박소생술 지도가 더 효율적임이 나타났다. Objectives : By comparatively analyzing the accuracy of and fatigue felt by ordinary persons who have received CPR training when he/she performs hands-only CPR (HOCPR) that entails only chest compressions and traditional CPR (TCPR) that entails chest compressions and rescue breathing, we attempt to provide baseline data for the creation of dispatcher guidelines for the general public. Methods : Using ordinary persons who have received CPR training (lasting less than 4-hours) at least 6-months prior through the Emergency Medical Information Center as subjects, hands-only CPR (HOCPR) was conducted by 52 subjects and traditional CPR (TCPR) was conducted by 48 subjects for a 2-minute duration. The accuracy of chest compressions was measured using the 2010 American Heart Association; the fatigue levels of before-experiment and after-experiment were measured; and the subjective fatigue levels were measured through a questionnaire. Results : Although the HOCPR experimental group showed higher scores, compared to the TCPR experimental group, in the accuracies for average depth, chest compression depth and chest compression location in terms of the accuracy for chest compressions, there were no significant differences. However, there were significant differences between the two experimental groups in terms of the accuracies for average speed and chest compression speed. In terms of the changes in heart rate and oxygen saturation before-experiment and after-experiment for measuring physiological fatigue levels, although the HOCPR experimental group showed less changes, there were no significant differences. In terms of the subjective fatigue levels, there were significant differences between the two experimental groups with the HOCPR experimental group showing lower subjective fatigue levels. Conclusions : In the results of comparing the chest compression accuracies and fatigue levels in performing hands-only CPR (HOCPR) and traditional CPR (TCPR) using as subjects ordinary persons who have received CPR training, the experimental group that performed HOCPR showed better accuracy in terms of compression speed and showed lower fatigue levels. As such, these results showed that, for conducting voice-instructed CPR training on ordinary persons who have been trained, HOCPR training would be more effective.

Cr2O3/Fe3O4 코어/쉘 나노 입자의 교환 바이어스

윤병길 인하대학교 대학원 2011 국내석사

본 논문에서 반강자성/강자성 Cr2O3/Fe3O4 코어/쉘 나노 입자의 교환 바이어스(Exchange Bias; EB)를 연구하였다. 코어에 해당하는 Cr2O3는 고체 상 반응과 볼 밀링을 하여 얻었고, 쉘에 해당하는 Fe3O4는 철 산화물 도금 방법을 이용하였다. Cr2O3/Fe3O4 나노 입자는 자기장 냉각 (Field-cooling ; FC) 후 5 K에서 자기이력곡선의 측정 결과 수평(HEB~610 Oe) 및 수직(ΔM~5.6 emu/g) 이동을 보였다. 그리고 이 곡선의 이동은 Cr2O3의 Neel 온도(TN ~ 307 K)보다 낮은 300 K근처에서 사라졌다. HEB와 ΔM 값은 매우 큰 훈련 효과 (Training Effect)를 보이는데, 첫 번째와 두 번째 자기장 순환 사이에서 급격히 감소하였고, 이 이상의 순환에서는 천천히 감소하였다. 이 결과는 고정되고 비 보상된 강자성 스핀으로 이루어진 단일 자구가 형성되고 이 단일 자구가 자기장의 순환에 따라 다중 자구로 변화되는 것으로 해석 할 수 있었다.

Gastrodia elata enhances memory function.

윤병길 Kangwon National University 2010 국내석사

Gastrodia elata blume (GEB) is a Chinese herb that has been used as an anticonvulsant, analgesic and sedative agent. Accumulated evidences indicate that GEB might be effective at preventing the development of Alzheimer's disease (AD). In the present study, we examined whether the methanol extract of GEB (MEG), containing gastrodin and p-hydroxybenzyl alcohol could be effective in protecting against the memory deficits and neuronal toxicity induced by exogenous beta-amyloid (1 - 42) and trimethyl-tin (TMT) in mice. MEG had significantly attenuated memory impairments and hippocampal changes in the acetylcholine level and acetylcholinesterase activity induced by beta-amyloid (1 - 42). Furthermore, MEG had significantly attenuated behavioral deficits and hippocampal cell death induced by TMT. These results suggest that the use of MEG exerts beneficial effects on the neurodegeneration in response to beta-amyloid and TMT.