• Journal of Chest Surgery
• /
• v.14 no.4
• /
• pp.331-338
• /
• 1981

The inhalation of a foreign body into the tracheobronchial tree is a child is a life-threatening accident. Forgotten foreign bodies In the airways cause chronic pulmonary infections, allergic asthma, bronchiectatic changes, and lung abscess Foreign bodies that cannot be grasped by bronchoscopic forceps should be removed by thoracotomy and bronchotomy. This report describes our experience In 16 patients who were treated to remove inhaled foreign bodies from the airways after repeated bronchoscopies had been unsuccessful from 1963 to 1981 at the department thoracic surgery of Seoul National University Hospital. The surgical procedures are as follows: 12 patients bronchotomy, 2 patient pneumonectomy, 2 patients lobectomy. In these cases, the foreign bodies are 8 metallic material, 3 plastic material, 1 bean, 1 black snail, and 3 cases of no records. Bronchotomy must be performed as soon as possible in order to avoid more advanced pathologic changes In the Involved lung, such as bronchiectasis, fibrosis or abscess.

• Food Science and Preservation
• /
• v.2 no.1
• /
• pp.185-193
• /
• 1995

This paper was investigated the changes of the cell wall components, enzyme activities during ripening of jujuba fruits for elucidating the softening metabolism of jujuba fruits. Firmness were decreased during ripening. Moisture content did not show any notable cahanges until ripening stage but they decreased a little In overripe jujuba fruits. Polygalacturonase activities were not detected at nature green stage and $\beta$-galactosidase activities were until turning stage. But polygalacturonase activities in ripening and overripening were 51.31 and 100.72 units/100g-fr, wt. respectively. $\beta$-galactosidase activities were 16.05 and 182.55units/100g-fr. wt. in the same stages. The content of water-soluble protein was increased in overripening. Stage the contents of cell wall and alcohol-insoluble material were. decraesed during maturation, but water-soluble material was increased. The pectin and alkali-soluble hemicellulose were increased until ripening stage, but decreased in overripe jujube fruits. The total pectin and insoluble pectin during ripening, but decreased in overripe jujuba fruits.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.32 no.3
• /
• pp.234-240
• /
• 2019

In this work, the magnetic arc reduction phenomena encountered in AC relay contacts were analyzed. To this end, arc duration, instantaneous voltage, and current changes due to changes in the magnetic field were observed. The arc generated at the contact point was affected by the magnitude of the applied magnetic field; the voltage and current waveforms rapidly intersected, resulting in a decrease in arc duration and arc energy. Furthermore, the orientation of the N pole of the magnetic field was found to play a role in the effectiveness of potential arc prevention.

• Journal of Biomedical Engineering Research
• /
• v.28 no.6
• /
• pp.721-726
• /
• 2007

The study relates to achievement and analysis of 3-dimensional spatial pulse wave archived by a spatially arterial pulse diagnostic apparatus (SAPDA), wherein a pulse sensing part array consists of multiple hall devices and is located over a skin contacting part which consists of a magnetic material. When a radially arterial pulse is transferred to the magnetic material, which is contacted skin that results in changes in a magnetic field of the lower part of the pulse sensing part array, the changes in a magnetic field can be detected by the commercial Hall semiconductor device of the pulse sensing part array. Finally, according to development of SAPDA, the 3-dimensionally arterial pulse waveform can be measured noninvasively by detecting the changes of the magnetic field.

• Journal of Environmental Health Sciences
• /
• v.33 no.5
• /
• pp.451-455
• /
• 2007

This study was performed to evaluate the effects of input ratios of bulking material in aerobic composting of food wastes on variation of colony forming units(CFU) of fungi. Wood chips were used as a bulking material. Volume ratios of food wastes to wood chips in reactor of Control, WC-1 and WC-2 were 10/0, 10/5 and 10/10, respectively. Reactors were operated for 24 days with I hour stirring by 1rpm and 2 hours of the forced aeration rate of $80L/min{\cdot}m^3$ per day. WC-2 reached high temperature range faster than WC-1, and the maximum temperature of WC-2 was higher than that of WC-1. WC-2 reached high pH range faster than WC-1. and the maximum pH of WC-2 was higher than that of WC-1. WC-2 reached high Log(CFU/gram) range faster than WC-I, and the maximum Log(CFU/gram) of WC-2 was higher than that of WC-1. These all mean that the reaction velocity of composting of WC-2 was faster than that of WC-1. The profile of fungi changes in Log(CFU/gram) was similar to that of temperature changes (r=0.8861) not pH changes (r=0.1631).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.64-64
• /
• 2010

This paper presents the results of changes of optical properties of front materials in crystalline PV modules. If PV modules on the outdoor, transmittance of front materials is reduced by solar light. That is UV, IR included Solar spectrum will have change the properties of glass. Therefore decrease in transmittance leads to loss of the PV modules output. All the PV modules showed the loss in Isc by 1~5% within few hors. To investigate the changes we are analyzed using spectrophotometer from raw glass to laminated glass.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.46-47
• /
• 2008

Organic light-emitting diode is quick response speed, low power consumption and the self-interest has many advantages, such as insanity. So, organic light-emitting diode mechanism of light-emitting diode in order to more clearly understand the changes in the thickness of emitting materials for OLED characteristics of the simulation. emitting layer to a thickness of 10 [nm] ~ 100 [nm] changed the experiment, and hole transport layer 190 [nm] as a fixed. and emitting layer 10 [nm] ~ 100 [nm] to change the simulation results. Changes in the thickness of emitting layer gradually increased. depending on the emitting was 20 [nm] in the high 441 [lm / W] shows. and was gradually reduced. emitting layer 190 [nm] when fixed, hole transport layer, depending on changes in the thickness of 70 [nm] in the efficiency maximum value of 477 [lm / W], and was gradually reduced.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.315-318
• /
• 2004

The Advantages of hot machining are the reduction of cutting forces, tool wear, and the increase of material removal rates. In this study, a hot-machining characteristics of milling by CBN tip was exprimentely analyzed, and the influence of the surface temperature and the depth of cut on the tool life were investigated. The selection of a heating method for obtaining ideal temperature of metals in machining is important. Faulty heating methods could induce unwanted structural changes in the workpiece and increase the cost. This study uses gas flame heating. It is obtained that tungsten carbide-alloyed has a recrystallisation temperature range of $800-1000^{\circ}C$ which is the high heating temperature that might induce unwanted structural changes. If it is performed at temperatures higher than $800^{\circ}C$ in machining, the possibility of unwanted structural changes and the increased wear of tool can be shown. Consequently, in hot machining of tungsten carbide-alloy, this study has chosen $400^{\circ}C-600^{\circ}C$ because the heating temperature might be appropriate in view of the cost and workpiece considerations. The results of this study experimentally shows a new machining method for tungsten carbide-alloyed that decreases the wear rate of machining tools

• The Journal of Korean Academy of Prosthodontics
• /
• v.33 no.1
• /
• pp.24-31
• /
• 1995

This study was performed to investigate the color stability and shear bond strength of denture repair resins. The denture base resins used in this study were Premium Super-20(Lang Dental Mfg. Co., Inc.,.U.S.A.) as heat curing resin, Triad VLC Denture Base(Dentsply/York Division, U.S.A.), Triad Reline Material(Dentsply/York Division, U.S.A.), Repair Acrylic(Lang Dental Mfg. Co., Inc.,. U.S.A.), Toughron Rebase (MikiChemical Product, Kyoto, Japan), and Tokuso Rebase(Tokuyama Soda Co., Ltd., Japan) as denture repair resin. After fabrication of specimens, they stored for 20 months, then color changes and shear bond strength were measured by colorimeter(Model TC-6FX, Tokyo Denshoku Co.) and Instron Universial Test Machine. The results were as follows : 1. There were changes of $L^{\ast},\;a^{\ast},\;b^{\ast}$ and $DE^{\ast}$ in Triad VLC Denture Base after 20 months. 2. There were changes of $a^{\ast}$ in Toughron Rebase and Tokuso Rebase, and $b^{\ast}$ in Tokuso Rebase after 20 months. 3. The shear bond strength of Repair Acrylic and Toughron Rebase were higher than that of Tokuso Rebase and Triad Reline Material.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.4
• /
• pp.350-356
• /
• 2005

We report the space charge and the surface potential of the interface between metal and copper(Ⅱ)-phthalocyanine(CuPc) thin films by measuring the microwave reflection coefficients S/sub 11/ of thin films using a near-field scanning microwave microscope(NSMM). CuPc thin films were prepared on Au and Al thin films using a thermal evaporation method. Two kinds of CuPc thin films were prepared by different substrate heating conditions; one was deposited on preheated substrate at 150。C and the other was annealed after deposition. The microwave reflection coefficients S/sub 11/ of CuPc thin films were changed by the dependence on grain alignment due to heat treatment conditions and depended on thickness of CuPc thin films. Electrical conductivity of interface between metal and organic CuPc was changed by the space charge of the interface. By comparing reflection coefficient S/sub 11/ we observed the electrical conductivity changes of CuPc thin films by the changes of surface potential and space charge at the interface.