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TiO₂광촉매를 이용한 chloromethane류의 분해 특성
신중혁,전진 동신대학교 환경연구소 2004 환경연구 Vol.9 No.1
Titanium alkoxide를 가수분해하여 제조한 TiO₂ sol을 glass bead에 코팅한 다음 dichloromethane과 trichloromethane의 광분해 특성을 살펴보았다. 두 화합물의 광분해율은 50% 이하로 낮은 제거율을 보였으며, 초기농도가 100ppm정도의 낮은 범위에서는 농도에 따라 제거율이 증가하는 유사 1차 반응의 형태를 보였다. O₃과 H₂O₂의 첨가 용액에서 Chloromethane의 광분해 증가율이 크게 증가된 결과로부터 할로메탄의 분해는 조사된 UV 빛에 의해서라기보다 TiO2에 의해 생성된 라디칼 반응에 의존함을 확인할 수 있었다. Photodegradation properties of dichloromethane and trichloromethane were investigated by using the glass beads coated with TiO2 sol hydrolyzed by titanium alkoxide. Relatively low removal ratio that is below 50% was observed in those compounds and showed pseudo first order reaction type at low initial concentration. From the results of increased removal ratio in the solution added with 03 or H202, photo degradation of chloromathanes are mainly obeyed by the radical reaction rather than UV light irradiated.
Hydroxyapatite를 이용한 기능성 환경소재 개발
전진,신중혁 동신대학교 환경연구소 2003 환경연구 Vol.8 No.1
HAp를 환경소재로써 응용은 도모하기 위하여 항균성과 중금속 제거 등의 다 기능성을 가지면서 수중에서 일정 강도 이상을 계속 유지 할 수 있는 bead형태의 성형화 된 HAp를 제조하였다 900℃로 소성한 bead에 비해 500℃로 소성한 bead에서 중금속 제거율이 현저히 높게 나타났다. 실제 공정에 적용하기 위한 연속식 장치에서의 결과는 중금속 제거뿐만 아니라 pH까지 동시에 조절할 수 있었다. 음이온의 제거에서는 전기음성도가 큰 F^(-)의 제거율이 높았으나, Cl^(-), Br^(-)의 제거율은 매우 낮았다 Ag가 첨가된 HAp bead는 우수한 항균성을 나타내었다. 이상의 결과로부터 성형화 된 HAp는 중금속제거 및 pH조절 그리고 음이온 제거와 항균성 등의 다 기능성을 보유한 훌륭한 환경소재로써 활용할 수 있음을 알 수 있었다. Pelletized hydroxyapatites[Ca_(10)(PO₄)_(6)(OH)₂:HAps] which are stable in the wastewater and possess multi-functional properties such as antibacterial activity and high ion-exchangeability were manufactured by the milling method to promote its application as an environmental material. The removal rate of Pb^(2+) was much higher at the sample calcinated at 500°C than that of 900°C. The results of continuous flow system were revealed that the pelletized HAp could control both the concentration of heavy metal ions and pH simultaneously. The removal rate of the anions was greatly influenced by the electronegativity of the anion, and fluoride ion showed the highest removal rate among the halide ions. HAp bead contained 1.75wt% of Ag that was made by wet impregnation method showed a good antibacterial activity regardless the calcination temperature. From all the results, it can be confirmed that the HAp bead has functional properties such as ion-exchangeability, pH controlling, and antibacterial activity
마이크로 컴퓨터에 의한 심전도 데이타 압축 알고리즘의 개선
이명호,이경중,황선철,정혁구 연세대학교 대학원 1988 延世論叢 Vol.24 No.-
This paper represents an improved ECG data reduction algorithm which is very useful for real time ECG analysis based-on microcomputer. In order to increase data reduction rate of Turning Point(TP), existing real time data reduction algorithm. The results obtained from the improved Modified Turning point(MTP) data reduction algorithm applied to three different pattern ECG signals. (1) The average data reduction rate of MTP algorithm is 67%, which is increased by 17% than that of TP algorithm. (2) The average percent rms difference(APRD) which is a normalized value that indicates the error between two signals is 9.4% for TP algorithm, while the APRD of MTP algorithm is 6.2% for MTP algorithm. It means that the PRD can be improved by 3.19. Therefore, it gives more excellent resolution than that of TP algorithm.
工業敎育大學의 實驗實習施設 共同活用 및 運營에 關한 硏究
尹錫天,牟相榮,權五憲,千炳善,周赫鍾,李永臣,金健中,羅聲雄,洪錫雨,吳德成,盧泰天 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)
The College of Engineering was specialized to have a sole function for supplying technical high school teachers in 1977 and referred to as the College of Industrial Education according to the Government's policy. The economic impact mainly due to the oil-crises caused a severe problem to this college, namely discrepancy of supply to demand scale. Accordingly the number of student enrollment was to be fluctuated from 479 in 1979 through 800 in 1979 and 900 in 1980 to 430 in 1981. And the engineering departments have been attached to this Engineering Education College since 1981. These circumstanses met singnificant inefficiency in facility operation. This program aims at providing an overall relocation of the college facilities and preparing the practical system to make the joint-operation possible taking into account circulation, academic stream, budget, maintenance, etc. However this study could not get optimal spacing but some trade-off, considering the current situation.
Joong-Hyeok Heo,Dal-Heui Lee,고동찬,Ho-Wan Chang 한국지질과학협의회 2007 Geosciences Journal Vol.11 No.3
The objective of this study is to evaluate the effect ofionic strength and hardnes of trichloroethylene (TCE)-contami-nated synthetic groundwater on remediation using granular acti-vated carbon (GAC). The TCE sorption rate onto GAC in syntheticfrom 86.2% to 100%. As the ionic strength and hardness of thesynthetic groundwater increased, the TCE sorption rates decreased.The sorption kinetics of the GAC were also analyzed by kineticmodels. The Elovich model was more successfuly applicable to thesorption kinetics than the Pseudo-first-order model. During thesorption, a greater amount of cations in groundwater were adsorbedthan anions. The sorption capacity of GAC was affected by cationsin groundwater. The GAC surface area was 958.98 m2/g and the2/g, whichcomprised 33.2 % of the GAC surface area. Our experimentsshowed that TCE remediation was influenced by the ionic strengthand hardness of groundwater. The results of these experimentswere confirmed by two different models and sorption areas.Therefore, the ionic strength and hardnes of groundwater mustbe considered in the remediation of TCE-contaminated ground-water using GAC.
Beat map drawing method for large oriental bell based on operational deflection shape method
Joong Hyeok Lee,In Seok Park,Seockhyun Kim 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10
Oriental bells produce a peculiar sound in the form of beats, which are periodic repetitions of strong and weak sounds. A beating sound with a proper period gives the illusion of the bell being alive and breathing. To produce a good beating sound, appropriate modal parameters are required for beat tuning after casting the bell. Conventionally, modal parameters were extracted using frequency response functions of the excitation and response signals. However, a large oriental bell is usually struck by a heavy wooden hammer and hence, only the response signal can be measured. In this study, we extract the modal parameters using the response signal only and employ the data to predict the beat properties of the bell sound. Finally, the validity of the predicted beat properties is experimentally verified for a large oriental bell.