• 대한기계학회논문집B
• /
• 제24권6호
• /
• pp.852-859
• /
• 2000

The emission in the exhaust gas from diesel engine is effected by the fuel spray characteristics. The spray of D.I. diesel engine impinges on a piston cavity and a cylinder wall. It is very important to know exactly the distribution and behavior of the spray inside cylinder. The objective of this study is to develop more accurate evaporation model. The EPISO code was used to analyze the flow characteristics in the engine. The Wakil model and the Faeth model are applied to the EPISO code to analyze the behavior of impinging spray. And also experimental and numerical analysis were carried out. The spray behavior characteristics were investigated by changing injection pressure, ambient pressure and temperature. The behavior of impinging spray was strongly effected by the change of ambient pressure and temperature. The effects of evaporation and rebounding droplet should be considered.

• Journal of Chest Surgery
• /
• 제22권6호
• /
• pp.1084-1087
• /
• 1989

Subannular aortic aneurysm is a word-wide rare disease entity occurring predominantly in young black men. In Korea, there has been no report. We report one patient, 46 years old man, who had been operated urgently because of acute aortic insufficiency and aortic valvular vegetation after antibiotics treatment of Subacute bacterial endocarditis for 6wks. At the operative field, We found the bulging aneurysmal mass between the aorta and superior vena cava above the right pulmonary artery, which has subannular communicating opening into the left ventricular cavity, beneath the anterior commissure of the bicuspid aortic valve. Pathologic findings are consistent with "portion of vascular wall with features of aneurysm.* The patients survived aortic valve replacement and patch closure of subannular aneurysm, with no symptoms at one-year postoperative follow-up.w-up.

• Journal of Chest Surgery
• /
• 제21권2호
• /
• pp.379-382
• /
• 1988

We have experienced a case of right side chylothorax following closed chest injury. A 35-year-old man in his car was accidentally collided against obstacles on September 19, 1986 resulting in a contusion on right anterior chest wall. The only complaint noted on admission was right chest pain. Chest X-ray showed near total radiopaque density of right thorax. Conservative treatment of closed tube thoracostomy at right pleural cavity through midaxillary 7th intercostal space had been continued for 25 days without improvement. Chyle outflow through the chest tube was averaging 1,700cc per day. Oversewing of the thoracic duct and pleura by silk and pledgetted prolene sutures were done. There was no complication and recurrence till postoperative 20 days. Chylothorax following closed chest injury was never reported in this country, and will be a interesting clinical case report.

• Journal of Chest Surgery
• /
• 제44권3호
• /
• pp.247-249
• /
• 2011

We report a case of pseudo-pseudoaneurysm, which is a very rare complication of myocardial infarction. A 69-year-old man was admitted to our clinic with chest tightness and dyspnea. He had undergone aortic valve replacement with a pericardial bioprosthetic valve, ring mitral annuloplasty, and reconstruction of an aortic annular defect due to infective endocarditis with bovine pericardium 4 years prior. Echocardiography and computed tomography showed pericardial effusion and a 16-mm cavity at the anterolateral wall of the left ventricle. Magnetic resonance imaging suggested either pseudo-pseudoaneurysm or myocardial abscess. We successfully repaired the myocardial defect using a patch made from a vascular graft with pledgeted horizontal mattress sutures under cardiopulmonary bypass.

• Journal of Korean Vacuum Science & Technology
• /
• 제3권1호
• /
• pp.24-29
• /
• 1999

The characteristic behaviors of CH3Br were examined first for the dry etching of polysilicon in a Cl2/CH3Br/O2 plasma. CH3Br is revealed one of the excellent additive gases to control anisotropy of etching profile and to give no undercutting for various typed of polysilicons. CH3Br acts as a passivation precursor on the side wall in etch cavity by forming polymer-like films such as CHxBry(x+y=1,2). The decrease of etch selectivity due to the reaction if the C-containing species from CH3Br with the surface O atoms of SiO2 was overcome by the addition of O2 into plasma, resulting that the selectivity increased by 2~3 times. According to the results of optical emission signals, CH3Br should be dissociated into several fragments to give more hydrogen atoms than bromine atoms in our helical resonator system.

• 대한기계학회논문집B
• /
• 제25권12호
• /
• pp.1879-1886
• /
• 2001

n a enclosed square cavity occurred B nard convection, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the visualized image. As the flowing in a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to the thermocapillary convection.

• 한국가시화정보학회지
• /
• 제4권2호
• /
• pp.6-10
• /
• 2006

The functional spherical microcapsules were produced through the innovative conjunction of the well-defined amphiphilic block copolymer and the stable droplet phase flow in the micro chemical plant. The microcapsules were formed to have hollow inner cavity and outer surface wall with nano-pores. To examine the potential of encapsulating foreign biochemical molecules, Congo-red dye was loaded into the microcapsule. The release performance in the specific surroundings such as temperature, pH and time was evaluated quantitatively.

• Journal of Chest Surgery
• /
• 제24권4호
• /
• pp.371-375
• /
• 1991

Postemetic rupture of the esophagus is an intrathoracic catastrophe which is universally fatal if untreated immediately. We have experienced one case of Boerhaave`s syndrome at the Thoracic & Cardiovascular Surgery Yonsei University College of Medicine. He was 56 years old male who complained severe chest-pain, dyspnea with sudden vomiting after alcohol. Esophagogram showed barium leakage through rupture site on lower esophagus into left thoracic cavity. He had taken repair of the rupture site of lower esophagus and wrapping it with the body of the stomach wall because of relatively clean rupture margin even though 48 hours following the rupture. He has been uneventful in post-operative courses & he discharged with good conditions.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.2185-2190
• /
• 2008

In a high speed train, multi-layered panels for floor, side wall and roof are important sound insulating part. As these multi-layered panels require high bending strength vs. weight, corrugated steels or aluminium honeycomb panel are generally used. However, with some inevitable factors, these panels show lower sound insulation performance than that of the plate with the same weight. Transmission loss(TL) often severely decreases in a particular frequency range because of the decrease of the critical frequency, occurrence of local resonance modes and cavity resonance modes, which are not shown in a plate. In this study, frequency range and cause of the TL drop are investigated on the corrugated and honeycomb panels.

• 소성∙가공
• /
• 제24권1호
• /
• pp.20-27
• /
• 2015

Hot tensile tests were conducted at different temperatures ranging from $20^{\circ}C$ to $550^{\circ}C$ to evaluate the mechanical properties of Al5052 seamless tubes. Such tubes can provide the technological foundation for complex forming using hot air bulging. Hot air bulging is one of the recently developed hydroforming techniques and it has some limitations in terms of cycle times. The benefits of hot air bulging are weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. In order to extend the forming limits of Al lightweight material hot air bulging was investigated. A heated tube was placed in a heated die and sealed at the ends by sealing cylinders. The heated tube was subsequently expanded against the die cavity wall by internal pressure using air medium. The results of the current study show that axial feeding speed and air pressure have an effect on the formability of Al tubes during air bulging at elevated temperatures.