• The Journal of Korean Academy of Prosthodontics
• /
• v.38 no.1
• /
• pp.108-115
• /
• 2000

This study was designed to compare the effect of polishing on surface roughness of composite resin. We used Z100(3M) composite resin and placed the composite resin in the hole (4mm thick and 4mm in diameter) of vinyl plate and polymerized it under manufacturer's instructions. Samples were divided into 5 groups by polishing methods. Group 1 was control: resin was polymerized under glass plate, Group 2: resin was polymerized without any polishing procedure, Group 3: resin was polymerized with a polishing procedure of abrasive disc, Group 4: bonding agent was applyed in thin layer and polymerized on the polished polymerized resin surface. Group 5: resin was polymerized under transparent celluloid strip. The surface roughness of each specimen was measured with Sufacoder SEF-30D (Kosaka lab. Ltd) under 0.08mm cut off, 0.05mm/s stylus speed, ${\times}40$ horizontal magnification, ${\times}5000$ vertical magnification. The results were as follows : 1. Group 1 showed the most smooth surface in this study. 2. Group 3 showed more rough surface than Group 2. Considering the surface roughness, it would be better to make the shape completely before polymerize the resin. To finish and polish after the polymerization of resin makes less smooth surface. 3. When we use the transparent celluloid strip, minimum finishing procedures are recommended. Any polishing procedure could not recover the smooth resin surface of celluloid strip. 4. Application and polymerization of the thin layer of bonding agent on the polished surface showed the minimum surface smoothing effect.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.207-207
• /
• 2011

Amorphous transparent oxide semiconductors (a-TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). Recently, Nomura et al. demonstrated high performance amorphous IGZO (In-Ga-Zn-O) TFTs.1 Despite the amorphous structure, due to the conduction band minimum (CBM) that made of spherically extended s-orbitals of the constituent metals, an a-IGZO TFT shows high mobility.2,3 But IGZO films contain high cost rare metals. Therefore, we need to investigate the alternatives. Because Aluminum has a high bond enthalpy with oxygen atom and Alumina has a high lattice energy, we try to replace Gallium with Aluminum that is high reserve low cost material. In this study, we focused on the electrical properties of IZO:Al thin films as a channel layer of TFTs. IZO:Al were deposited on unheated non-alkali glass substrates (5 cm ${\times}$ 5 cm) by magnetron co-sputtering system with two cathodes equipped with IZO target and Al target, respectively. The sintered ceramic IZO disc (3 inch ${\phi}$, 5 mm t) and metal Al target (3 inch ${\phi}$, 5 mm t) are used for deposition. The O2 gas was used as the reactive gas to control carrier concentration and mobility. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of IZO:Al thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Journal of Oral Medicine and Pain
• /
• v.19 no.1
• /
• pp.125-136
• /
• 1994

Observation of elastic fiber's change of mouse TMJ due to several round factor, principally external stimulations, their influence on the TMJ structure's change and the analize of the consecutive evolution of the disease in most important. So, the author believe that the factor of TMJ feature is the elastic feature's change and it's the principal factor of the TMJ disease. For observation of the increase and disposition of elastic fiber that to regulate the elastic feature of tissue and allow it existence. For this propose, observation with histologic methods on 20mouse ICR of 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. The results were as follow : 1. In the early stage, the condyle of TMJ is originated from cartilage mass, and it's calcification is endochondral. 2. In the early stage, the disc is relatively thin and immature, but in the later stage the fiber is dense and the disposition is most functional. 3. Observation of the early stage, the elastic fiber is a thin fiber that to across antero- posterior direction, but in the later stage elastic fiber are developed, the disposition that in the early stage was perpendicular to articular surface, now in parallel. 4. The elastic fiber was observated most clearly in the retrodiscal tissue. 5. In conclusion, the elastic fiber is observed like a thin fiber 1 week from born, but the fiber to increase the weight and it dispose functionally, and 4 week from born, it can realize the normal function.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.79-80
• /
• 2002

This paper presents an experimental study of the effect of rolling speed and surface roughness on the mixed elastohydrodynamic (EHD) lubrication characteristics for point contact formed between a real, random, rough surface, steel ball and smooth glass disc. The Thin Film Colorimetic Interferometry measurement technique has been extended to give detailed information about in-contact deformation of the microgeometry. It has enabled to derive the amplitude reduction curve that shows progressive recovering of ball roughness features with increasing speed.

• Proceedings of the KOSOMBE Conference
• /
• v.1992 no.05
• /
• pp.123-126
• /
• 1992

In this paper, a numerical simulation of steady laminar and turbulent flow in a two dimensional model for the total artificial heart is presented. A trileaflet polyurethane valve was simulated at the outflow orifice while the inflow orifice had a trileaflet or a flap valve. The numerical solutions of the simulated model show that regions of relative stasis and trapped vortices were smaller wi thin the ventricular chamber wi th the flap valve at the inflow orifice than that with the trileaflet valve. The predicted Reynolds stresses distal to the inflow valve within the ventricular chamber were also found to be smaller with the flap valve than with the trileaflet valve. Analysis of the numerical solutions suggests that geometries similar to the flap valve(or a tilting disc valve) results in a better flow dynamics within the total artificial heart chamber compared to a trileaflet valve.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.1
• /
• pp.12-19
• /
• 2001

In this study, the physical properties of the piezoelectric sounder with metal-piezoelectric ceramics were analyzed. The dielectric and piezoeletric properties of 0.5wt% MnO$_2$ and NiO doped 0.1Pb(Mg$\_$1/3/Nb$\_$2/3/)O$_3$-0.45PbTiO$_3$-0.45PbZrO$_3$ ceramics were investigated aiming at acoustic transducer applications. The acoustic characteristics of a thin circular disc-type with metal-piezoceramics have been investigated. Also, the acoustic characteristics for the geometrical form of case were investigated. The piezoelectric sounder with 200kHz resonant frequency and 20kHz bandwidth was designed by considering the sharp directivity and the sound pressure.

• Journal of the Korean Magnetics Society
• /
• v.1 no.1
• /
• pp.30-36
• /
• 1991

A measurement system for magnetic anisotropy was built. The torque acting on the disc or sperical samples placed in uniform magnetic field was detected with a capacitive transducer which is connected with a transformer ratio-arm bridge. The output of the bridge was amplified with a lock-in amplifier. The cubic anisotropy constant for (100) of 3% Si-Fe was $3.3{\times}10^{4}\;J/m^{3}$. The calibration for the system was carried out with the shape anisotropy of a thin Ni wire.

• Mycobiology
• /
• v.37 no.1
• /
• pp.31-36
• /
• 2009

A phytochemical study on the flower of Calotropis gigantea (Linn.) using silica gel column chromatography and preparative thin layer chromatography, led to the first time isolation of Di-(2-ethylhexyl) phthalate (compound 1) and anhydrosophoradiol-3-acetate (compound 2). The structures of these compounds were confirmed by spectroscopic analyses (IR, HRTOFMS and NMR). The antibacterial and antifungal activities of ethyl acetate extract, compound 1 and compound 2 were measured using the disc diffusion method. Ethyl acetate extract and compound 1 presented better results than compound 2. The minimum inhibitory concentrations (MICs) of the extract and compounds were found to be in the range of $16{\sim}128{\mu}g/ml$. The cytotoxicity ($LC_{50}$) against brine shrimp nauplii (Artemia salina) were also evaluated and found to be 14.61 ${\mu}g/ml$ for ethyl acetate, 9.19 ${\mu}g/ml$ for compound 1 and 15.55 ${\mu}g/ml$ for compound 2.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.684-687
• /
• 2002

In optical disk drive(ODD), pickup actuator, which comprises a key part of an optical disk drive equipment. must be thin. compact, and high sensitive. Low tilt is also an important requirement for the actuator, since optical disks are to high density. This tilt occurs from around the axis parallel to the tangential and radial direction of the disk. The main reason of the moment is the coupling effect between focus driving system and tracking driving system. This paper analyzed tut quantity due to focusing and tracking force through coupled fields analysts with electromagnetic analysis and structural analysis.

• YAKHAK HOEJI
• /
• v.25 no.4
• /
• pp.137-143
• /
• 1981

In order to confirm the exact antipyretic component in the earthworm, etherial extract of American earthworm(Red Worm) was fractionated into five fractions by using silica gel column chromatography and thin layer chromatography. The fraction including free fatty acids was found to possess artipyretic response and standard arachidonic acid showed marked antipyretic response on typhoid vaccinated rabbits. Arachidonic acid was identified from the free fatty acid fraction of the earthworm by using gas liquid chromatography. Thus it was considered that the antipyretic activity of the free fatty acid may be due to the presence of arachidonic acid. Lipid-free earthworm powder was extracted with phosphate buffer (pH, 8.0, 0.1M) and all the proteins was salted out by ammonium sulfate. The crude precipitate was dialyzed and the impure proteins were eliminated at pH 5.4 and 4.6. The remaining protein solution was fractionated with various concentrations of acetone. The acetone fractions were identified by using S.D.S. polyacrylamide gel electrophoresis and disc gel electrophoresis. The precipitate at 85% acetone concentration and the remaining proteins in the supernatant did not exhibit the antipyretic activity.