Emissions of hazardous substances in automobiles are caused by combustion of internal combustion engines, friction of brake pads and tire wear. In this study, we propose a method to reduce the harmful substances emitted in internal combustion engine by using HHO gas. In order to reduce the exhaust gas of the internal combustion engine, HHO gas having excellent combustion characteristics was added to the combustion chamber. The HHO gas generator was installed in the intake line and the HHO gas was introduced into the combustion chamber with the mixed gas through the intake line. At this time, we compared and analyzed the performance of the engine performance on the presence and absence of HHO gas.
In this study variable radius pulley is proposed, and the proposal should be applied to pulley of CVT. Variable radius pulley consists of two disks and sliding pins. Phase difference of two disks make a change pitch diameter. Therefore change speed is accomplished by changing pitch diameter of pulley. In this paper simulation for slot variation of rotary disk of the variable radius pulley was performed. Softwares for simulation are Pro/Engineer5 and Hypermesh11.0. The results of simulation are appropriate to put to practical use of the variable radius pulley
Many countries of the world has been devoting a lot of effort to reduce carbon emission. In order to reduce carbon emission, the high efficiency engine has been studied in the automotive industry. Of these, the spread and research of the diesel engine in Europe center are active. However the combustion characteristic of diesel engines have disadvantages of much NOx and soot emissions. In this study, the optimum regeneration point of the forced regeneration type DPF(Diesel Particulate Filter) that was equipped in medium-duty diesel vehicles using a mechanical fuel injection system have studied. DPF that is applied to the medium-duty diesel vehicle has a bent inlet pipe. The flow distribution characteristics of DPF according to the influence of the bent pipe have investigated. The flow distribution characteristics of DPF according to variation of the engine operating condition is considered to be useful data In order to decide the optimum regeneration point.
Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.
Recently, robot-assisted joint replacement surgeries are on the rise. Robot-assisted surgery can make more accurate outcome, and thus it will be more popular. For the accurate result, secure fixation of bone is necessary, but there are numerous difficulties for the secure fixation. Detecting bone motion is necessary to prevent some errors. Currently, optical sensor and location sensor are in use; however, these sensors can cause interventional problem for the friction between mechanical devices. This study shows how to compose the bone motion detecting device using electromagnetic sensor, how to commercialize the bone motion detecting device.
Recently, Clinical reports about reducing the delivery time, pain, instrument delivery, and C-section by increasing intrauterine pressure through giving a steady pressure on fundus have been released. However, the use of fundal pressure during the labor is a cause of great concern about medical malpractice and accidents caused by overpressure on fundus. To practice fundal pressure in safe way, medical device is designed. The device consists of inflatable belt, controller, and TOCO transducer; it inflates the belt to give air pressure onto fundus. In this study, we propose the shape of belt to give an air pressure on fundus equally, efficiently, and safely.
There are many types of reduction drives for industrial uses. However, it is essential to use precision reduction drives for accuracy of position controls on robot systems. Among the precision reduction drives, the cycloid reduction drive is well known for its high performances and widely used in precision industrial field. Cycloid reduction drives are mainly used in manipulators in robot system requiring a characteristic of a high precision control. When we design this cycloid reduction drive, there are many factors that must be considered. First, a geometrical analysis of a tooth shape must be drawn from the basic concept. Secondly, load distribution, stress distribution and sliding velocity on a tooth should be calculated exactly. Finally, a computer software to optimize the design of a cycloid tooth needs developing. In this study, many different kinds of factors concerning the characteristic of a cycloid tooth were researched on the basis of the analysis of load, stress and sliding velocity on a tooth. The computer expert system to design the cycloid reduction drive was developed using a Visual C++ compiler. In conclusion, the most important factors can be obtained easily as the user put the simple input data.
Catalytic activity changes of perovskite catalysts were examined with their A-site substitution. For the preparation of catalysts, Mn was used for B-site component and La, Ce, Sr, Ba, Ca, Ag were used for A-site component of the perovskite catalysts(ABO3) The effect of calcination temperature on methane combustion and perovskite structure was also investigated. The surface area and adsorbed oxygen species were tested with BET apparatus and O2-TPD, respectively. Perovskite catalysts whose A-site was partially substituted needed higher calcination temperature than un-substituted one to form the perovskite structure. From O2-TPD experiment, it was found that methane combustion activity was directly related to the oxygen desorbing ability of the catalysts. The prepared catalyst(LM-7) was stable at 600℃ for 72 hours of reaction.
Methane combustion over perovskite catalysts was investigated. For the preparation of catalysts, Co, Mn, Fe, and Ni were used as B-site components of the perovskite catalysts (ABO3) and La was used as A-site component. The effect of calcination temperature on methane combustion and perovskite structure was also investigated. The structure of perovskites, surface area, and adsorbed oxygen species were tested with XRD, BET apparatus, and O2-TPD, respectively. The formation of perovskite structure was affected by the calcination temperature. The catalyst desorbing oxygen at a lower temperature showed better activity for the methane combustion, therefore, the oxygen species desorbing at lower temperatures is responsible for the methane combustion.
Reaction conditions and catalysts were investigated for direct CF3I synthesis. Optimum reaction temperature was determined by pyrolysis of CF3H and catalytic reactions. Reactions with changing oxygen concentration were performed. As a result, yield of CF3I increased with decreasing oxygen concentration. Catalytic activity was changed with the weight ratio of the used metal salts. This result was stemmed from the change in the pore size of activated carbon by the metal salts. The optimum reaction conditions were: 600℃, space velocity of 45hr-1, and with 7wt% KF/AC catalyst.
본 논문에서는 최근 해안 환경을 더욱 친숙하게 이용하면서 건설된 부산 마린시티의 태풍 및 해일의 피해를 방지하기 위한 대책들에 대해 연구하였다. 마린시티를 바다 바로 앞에 건설하면서 태풍 및 침수피해가 늘 일어나고 있다. 마린시티 구역단면도와 침수피해 예측도를 통하여 파고의 높이에 따라 기존의 방조제가 해일을 막을 수 있는 한계와 침수예상을 통해 방재지도를 작성하였다. 이를 통해 임시 피난처 및 대피로를 지정하였고, 침수 위험단계를 4단계로 나누어 구역을 지정하였다. 피해를 저감해보고자 위험도 평가로 Hazard Analysis, Risk Analysis, Vulnerability Analysis를 실시하였고, 예방, 대비, 대응, 복구의 네 가지 단계를 통하여 대안을 도출해 보았다.
가시오갈피의 농가재배를 위한 기초자료를 얻고자 덕유산의 가시오갈피 자생지에 대한 환경특성과 생육상황에 관한 현지조사를 수행하여 분석한 결과는 다음과 같다. 1. 가시오갈피의 덕유산 자생지는 동경 127˚ 45', 북위 35˚ 52'의 해발 1,050～l,300m의 북경사면에 위치하고 있었다. 2. 자생지의 연평균기온은 5.8℃ , 최난월 (8월 )의 평균최고기온은 24.6℃ , 최한월 (1월 )의 평균최저기온은 -13.5℃ 로 추정되었으며, 상대습도는 95% 이상이었다. 3. 자생지의 기후는 냉온대 습윤기후로 구분되었으며 식물대는 낙엽광엽수림대로 나타났다. 4. 토양은 암갈색 자갈이 있는 사양토이며 유효토심은 20～50cm로서 얕았으며 토양의 pH는 5.2～5.6정도였고, 인산함량은 평균 10ppm으로 매우 낮았다. 5. 자생지내의 가시오갈피 생육은 낮은 조도(차광율 80%)로 인하여 매우 연약하게 자라고 있었으며, 번식은 실생번식이 아닌 근부맹아(root sucker)에 의한 영양번식을 하고 있었다. 6. 자생지 주변의 식생은 총 30여종이 발견되었으나 주로 까치박달나무 등의 교목 3종, 모감주나무 등의 관목 3종, 그리고 박쥐나물 등의 초본류 4종 등이 분포하고 있었다.
가시오가피(五加皮) (Eleutherococcus senticosus MAXIM)는 강장(强壯), 강간(强肝), 혈당강하(血糖降下). 항(抗)스트레스, 스테미너 보강등(補强等)에 효과(效果)가 있는 식물(植物)로 강원도 북부(北部) 및 덕유산(德裕山)에 자생(自生)하고 있으나 계식기술(繫繫殖技術)이 거의 개발(開發)되어 있지 않아 묘목(苗木)을 대량(大量) 생산(生産)키 위하여 삽목계식에 대한 일연(一連)의 시험(試驗)을 1990~1992년(年) 수행(遂行)한 결과(結果)는 다음과 같다. 1. 발근촉진제(發根促進劑) 처리(處理)에 의한 삽목후 Callus 형성(形成) 및 발근율(發根率)은 Rootone-F 분의처리(粉衣處理)가 IAA, NAA 및 IBA보다 양호(良好)하였다. 2. 삽수의 발근억제(發根抑制) 물질(物質) 제거처리(除去處理)는 삽목후 처리간(處理間) 차리(差異)가 없는 점으로 보아 억제물질(抑制物質)은 없는 것으로 판단(判斷)되었다. 3. 삽목시 발근(發根)이 잘되는 상토(床土)는 Perlite(1):Vermiculite(1)가 40%로 가장 좋았으며, 모래는 12%, 황토(黃土)에서는 전혀 발근(發根)되지 않았다. 4. 삽목시기(揷木時期)는 가시오가피(五加皮)는 9월(月) 20일(日)(반숙지삽(半熟枝揷)),지리오가피(五加皮)는 7월(月) 20일(日)(녹지삽(綠枝揷)) 또는 9월(月) 20일(一) 반숙지삽(半熟枝揷)에 삽목하는 것이 가장 좋았으며, 당오가피(五加皮)는 삽본시기 및 삽수에 관계(關係)없이 발근(發根)이 잘 되었다.