• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.743-744
• /
• 2011

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.3
• /
• pp.217-222
• /
• 2015

There has been increased amount of atmospheric pollutants including NOx and SOx which cause acid rain and photochemical smog as a result of increased use of fossil fuels. In order to reduce the amount of pollutants produced by fossil fuel, wet scrubber system is introduced in this experiment. Wet scrubber system is applied to a diesel engine (3,298 cc) and the amount of smoke is measured before and after the application in terms of aspect ratio, filling rate, and flow rate. The result showed a lot of smoke reduction when wet scrubber system was applied, and also the aspect ratios and water spray flow rate were the important factors to improve smoke reduction.

• Restorative Dentistry and Endodontics
• /
• v.25 no.2
• /
• pp.202-211
• /
• 2000

The aim of this study was to compare the apical sealing ability of a new thermoplasticized gutta-percha filling technique, the Easy Filling and the Quick Obturation system with lateral condensation technique and Thermafil system to evaluate their clinical acceptabilities. Fifty-two extracted single-rooted teeth were instrumented to #35 using the .04 taper ProFile system. Four groups of 12 teeth were obturated by lateral condensation technique. Thermafil system and two new thermoplasticized gutta-percha techniques, the Easy Filling system and Quick Obturation system (Meta Dental co. Ltd. Korea), respectively. Four teeth served as controls. After the teeth were immersed in 2% methylene blue dye for 48 hours, they were resected horizontally at 1mm to 5mm level from the anatomical apex using a low-speed microtome. Each section was examined under a stereomicroscope at ${\times40}$ magnification and photographed. After each image was scanned, the leakage area was measured at each level using Brain 3 (Nosdia Tech., Korea) software. Leakage ratio was calculated for each group and was analyzed statistically to come up with the following results: 1. At 1mm level, the Quick Obturation system had the largest amount of apical leakage and it was statistically significant when compared with the lateral condensation group and the Thermafil group (p<0.05). 2. At 2mm and 3mm level, there were no significant difference of apical leakage among all four groups (p>0.05), and from 4mm level, no apical dye penetration was observed in all the groups. In conclusion, the apical seal produced by Easy Filling system and the Quick Obturation system was comparable to lateral condensation technique and Thermafil system except for the 1mm level. More improvement of the apical seal can be expected as the operator becomes skillful with the new techniques.

• Korean Journal of Metals and Materials
• /
• v.48 no.7
• /
• pp.667-673
• /
• 2010

Copper filling into TSV (through-silicon-via) and reduction of the filling time for the three dimensional chip stacking were investigated in this study. A Si wafer with straight vias - $30\;{\mu}m$ in diameter and $60\;{\mu}m$ in depth with $200\;{\mu}m$ pitch - where the vias were drilled by DRIE (Deep Reactive Ion Etching) process, was prepared as a substrate. $SiO_2$, Ti and Au layers were coated as functional layers on the via wall. In order to reduce the time required complete the Cu filling into the TSV, the PPR (periodic pulse reverse) wave current was applied to the cathode of a Si chip during electroplating, and the PR (pulse-reverse) wave current was also applied for a comparison. The experimental results showed 100% filling rate into the TSV in one hour was achieved by the PPR electroplating process. At the interface between the Cu filling and Ti/ Au functional layers, no defect, such as a void, was found. Meanwhile, the electroplating by the PR current showed maximum 43% filling ratio into the TSV in an hour. The applied PPR wave form was confirmed to be effective to fill the TSV in a short time.

• Transactions of Materials Processing
• /
• v.16 no.1 s.91
• /
• pp.20-24
• /
• 2007

Polypropylene substrate with hair-like nano features(aspect $ratio{\sim}10$) on the surface is fabricated by injection molding process. Pure aluminum plate is anodized to have nano pore array on the surface and used as a stamper for molding nano features, The size and the thickness of the stamper is $30mm{\times}30mm$ and 1mm. The fabricated pore is about 120nm in diameter and 1.5 um deep. For molding of a substrate with nano-hair type of surface features, the stamper is heated up over $150^{\circ}C$ before the filling stage and cooled down below $70^{\circ}C$ after filling to release the molded part. For heating the stamper, stamper itself is used as a heating element by applying electrical power directly to each end of the stamper. The stamper becomes cooled down without circulation of coolant such as water or oil. With this new stamper heating method, nano hairs with aspect ratio of about 10 was successfully injection molded. We also found the heating & cooling process of the stamper is good for releasing of molded nano-hairs.

• Journal of the Korea Institute of Building Construction
• /
• v.4 no.3
• /
• pp.93-100
• /
• 2004

In recent years, it has widely been studied on the light-weight composites for the purpose of the large space and thermal insulation of building structures. The purpose of this study is to evaluate the properties of light-weight composites made by binders as cement, resin and polymer cement slurry. The concrete composites are prepared with various conditions such as polymer-cement ratio, void-filling ratio, type of resin, filler content and light-weight aggregate content, tested for thermal conductivity. From the test results, the thermal conductivity of concrete composites with the binder of cement tends to decrease with increasing polymer-cement ratio, and to increase with increasing void-filling ratio. The thermal conductivity of concrete composites with the binder of resin are markedly affected by the light-weight aggregate content, type of resin and filler content. The composites made by polymer-modified concrete and polymer cement slurry have a good thermal insulation property. From the this study, we can recommend the proper mix proportions for thermal insulation Panel or concrete. Expecially. the thermal conductivity of concrete composites made by polyurethane resin is almost the same as that of the conventional expanded polystyrene resin.

• Design & Manufacturing
• /
• v.11 no.3
• /
• pp.29-34
• /
• 2017

Increased demand for parts with micro-pattern structure made of metals, ceramics, and composites in various fields such as medical ultrasonic sensors, CT collimators, and ultra-small actuator parts. Micro powder injection molding (PIM) is a technology for manufacturing micro size, high volume, complex, precision, net-shape components from either metal or ceramic powder. In the present study, a standard mold with a variable insert core capable of producing various micro patterns was investigated. An injection molding test was performed on a standard mold using a line type micro-pattern core having an aspect ratio of 2, a slenderness ratio of 70, a pattern size of $200{\mu}m$, and a pattern spacing of $150{\mu}m$. During the filling process, the deformation of the mold with large aspect ratio and slenderness ratio was analyzed by the experiment and the numerical simulation according to the position of the gate. We proposed a mold structure that minimizes mold deformation by gate modification and enables uniform pattern filling behavior.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.3
• /
• pp.266-272
• /
• 2015

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature ($27^{\circ}C{\pm}4^{\circ}C$) treated both rice cultivars were decreased than those of control temperature ($22^{\circ}C{\pm}4^{\circ}C$) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

• Journal of Advanced Research in Ocean Engineering
• /
• v.3 no.3
• /
• pp.149-157
• /
• 2017

Since sloshing effects influences ship motions including floater's natural frequencies. The significant factors changing ship motions are inner liquid impact loads and inertia forces and moments with respect to its filling ratio. This means that changing sloshing loads with sloshing effects reduction device (SERD) may control ship motions. In this regard, conceptual model for adjustable SERD was suggested by authors and then implanted into fully coupled program between vessel motion and sloshing. By changing clearances of baffles in the inner tank which were component of SERD, then the roll RAOs from each case were obtained. It is revealed that using well-controlled SERD can maintain natural frequencies of floater even inner tank has different filling ratio.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.131-136
• /
• 2002

In recent year, it has been investigated on the reduction of mass of structures for the purpose of the larger space and the economy with the industry developing very fast and qualitatively. So the purpose of this study is to investigate the manufacture of light weight concrete panel using the artificial light-weight aggregate as a part of the substitution of foamed styrene and polyurethane because of narrow allocable temperature zone in use. The compressive strength, flexural strength, unit weight, absorption test and thermal conductivity were practised at 3, 7 and 28 days after manufacturing the light-weight concrete lot the panel core: the filling ratio of continuous void was defied as 40%, 50%, and 60% and water-cement rate was 35, 40 and 45%. As a result of this, it was revealed that the mixture derived from filling ration of void of 50% and water-cement ratio 40% were developing the best properties of the others.