• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.10
• /
• pp.1146-1152
• /
• 2011

Ink transfer process is very important to determine quality of printed pattern, therefore its mechanism should be understood to control printing quality. Although there have been many attempts to understand ink transfer mechanism by numerical simulation and experimental studies, their model was too much simple to model realistic printing process and our understanding is not enough yet. In this paper we designed ink transfer visualization system to present flow visualization of ink transfer process for gravure offset printing. We considered rotational effect of blanket roll which is related with printing speed and used non-Newtonian fluid as working fluid such as Ag paste. For printing unit, cantilever-type blanket roll is used for convenient visualization of ink transfer. Serial images were captured continuously by using high-speed CMOS camera and long range microscope. We investigated the effects of various design parameters such as printing speed and pattern angle on the ink transfer process. We found more stretched ink filament for non-Newtonian fluid than Newtonian fluid. As increasing printing speed, length of stretched ink filament and height of break-up point are also increased. We also compared ink transfer process between CD and MD pattern and its relationship with ink transfer mechanism.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.3
• /
• pp.382-389
• /
• 2013

Propionate is an important intermediate product during the methane fermentation of organic matter, and its degradation is crucial for maintaining the performance of an anaerobic digester. In order to understand the effect of temperature on propionate degradation, an upflow anaerobic sludge blanket (UASB) reactor with synthetic wastewater containing propionate as a sole carbon source was introduced. Under the hydraulic retention time (HRT) of 10 h and influent propionate of 2,000 mg/l condition, propionate removal was above 94% at 30-$35^{\circ}C$, whereas propionate conversion was inhibited when temperature was suddenly decreased stepwise from $30^{\circ}C$ to $25^{\circ}C$, to $20^{\circ}C$, and then to $18^{\circ}C$. After a long-term operation, the propionate removal at $25^{\circ}C$ resumed to the value at 30- $35^{\circ}C$, whereas that at $20^{\circ}C$ and $18^{\circ}C$ was still lower than the value at $35^{\circ}C$ by 8.1% and 20.7%, respectively. Microbial community composition analysis showed that Syntrophobacter and Pelotomaculum were the major propionate-oxidizing bacteria (POB), and most POB had not changed with temperature decrease in the UASB. However, two POB were enriched at $18^{\circ}C$, indicating they were low temperature tolerant. Methanosaeta and Methanospirillum were the dominant methanogens in this UASB and remained constant during temperature decrease. Although the POB and methanogenic composition hardly changed with temperature decrease, the specific $COD_{Pro}$ removal rate of anaerobic sludge (SCRR) was reduced by 21.4%-46.4% compared with the control ($35^{\circ}C$) in this system.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.8
• /
• pp.1409-1419
• /
• 2016

The effect of pH on propionate degradation in an upflow anaerobic sludge blanket (UASB) reactor containing propionate as a sole carbon source was studied. Under influent propionate of 2,000 mg/l and 35℃, propionate removal at pH 7.5-6.8 was above 93.6%. Propionate conversion was significantly inhibited with stepwise pH decrease from pH 6.8 to 6.5, 6.0, 5.5, 5.0, 4.5, and then to 4.0. After long-term operation, the propionate removal at pH 6.5-4.5 maintained an efficiency of 88.5%-70.1%, whereas propionate was hardly decomposed at pH 4.0. Microbial composition analysis showed that propionate-oxidizing bacteria from the genera Pelotomaculum and Smithella likely existed in this system. They were significantly reduced at pH ≤5.5. The methanogens in this UASB reactor belonged to four genera: Methanobacterium, Methanospirillum, Methanofollis, and Methanosaeta. Most detectable hydrogenotrophic methanogens were able to grow at low pH conditions (pH 6.0-4.0), but the acetotrophic methanogens were reduced as pH decreased. These results indicated that propionate-oxidizing bacteria and acetotrophic methanogens were more sensitive to low pH (5.5-4.0) than hydrogenotrophic methanogens.

• Journal of Bio-Environment Control
• /
• v.14 no.1
• /
• pp.22-28
• /
• 2005

The use of blankets to preserve heat in oriental melon cultivation is a common practise without artificial heating and warming systems. Efficiency of blanket decreased with annually usage. This experiment was conducted to investigate the effect of double layer nonwoven fabrics on heat conservation, plant growth, fruit quality and yield of oriental melon in greenhouse. The results were compared among the non-woven fabrics of 9+3, 6+6, 6+3 and 12 ounce from transplanting to April 20, 2001, 2002. Night temperature within tunnel was high at 9+3, 6+6, 6+3 and 12 ounce in order. In plant growth, stem length, leaf numbers and exudate, under double layer nonwoven fabrics were better than single layer blanket of 12 ounce especially, 9+3 double layer blanket was the best. Fruit weight, flesh thickness, soluble solid and marketable yield rate remained same in all treatments. Fermented fruit rate was the highest in 12 ounce as $32.9\%,\;19.6\%\;under\;9+3,\;17.1\%\;under\;6+6,\;16.6\%$ under 6+3 double layer nonwoven fabric, respectively. Compared to 2,260kg yield per 10a of 12 ounce single layer nonwoven fabrics, $7\%$ was increased under 9+3 but $3\%\;and\;13\%$ were decreased under 6+6 and 6+3 double layer nonwoven fabrics, respectively. Compared to income, 4,499-thousand-won per 10a, of 12 ounce single layer blanket, $13\%\;and\;3$ were increased under 9+3 and 6+6 double layer nonwoven fabrics, respectively. Whereas, $10\%$ decreased under 6+3 double layer nonwoven fabrics. From this results it is evident that 9+3 double layer nonwoven fabrics was the best for thermokeeping, fruit quality, and was most economic under non heating system.

• Korean Journal of Materials Research
• /
• v.15 no.6
• /
• pp.426-430
• /
• 2005

Chemical mechanical polishing (CMP) is an essential process in the production of integrated circuits containing copper interconnects. The effect of alanine in reactive slurries representative of those that might be used in copper CMP was studied with the aim of improving selectivity between copper(Cu) film and tantalum-nitride(TaN) film. We investigated the pH effect of nano-colloidal silica slurry containing alanine through the chemical mechanical polishing test for the 8(inch) blanket wafers as deposited Cu and TaN film, respectively. The copper and tantalum-nitride removal rate decreased with the increase of pH and reaches the neutral at pH 7, then, with the further increase of pH to alkaline, the removal rate rise to increase soddenly. It was found that alkaline slurry has a higher removal rate than acidic and neutral slurries for copper film, but the removal rate of tantalum-nitride does not change much. These tests indicated that alanine may improve the CMP process by controlling the selectivity between Cu and TaN film.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.22 no.2
• /
• pp.101-110
• /
• 2004

The local surface strength variation of coated papers were measured at various speeds on a number of coated paper samples to study the effects of speed and ink tack on coating pick. Coating pick phenomenon is observed in an ink transfer variation curve as a decrease in the slope of the curve. On the other hand, it causes an actual decrease in net ink transfer to paper with an increase in speed. The effect of speed on coating pick depends on ink tack, ink film thickness and surface properties of coating layer formation of paper. A novel device to measure the surface strength can rate the coating paper in a different order. Comparison are made between dry test of coating paper pick and wet coating pick test of printing in IGT printability tester. Coating formulation is the main key to prevent from coating pick. The binder level increases, the coating pick and the slop decrease. The piling on blanket in printing is a problem when the coating pick is occur on a local area rather than average surface strength of coated papers.

• Journal of environmental and Sanitary engineering
• /
• v.13 no.2
• /
• pp.47-56
• /
• 1998

Effects of sulfate on the anaerobic substrate utilization were evaluated using UASB (Upflow Anaerobic Sludge Blanket) reactor. Effect of sulfate on the organic removal rate was dependent on the relative amount of microorganisms in the reactor, the operational condition, and the characteristics of sludge. When the sulfate shock was applied to 0.0 - 3.0g SO$_{4}$$^{2-}$/d, more than 95% of COD removal efficiency was achieved. Therefore, if F/M ratio was kept to low sufficiently with recirculation, it is shown that operation of the reactor was not affected significantly, though sulfate shock load was doubled compared to the normal operation. Provided that it is shocked by high strength of sulfate or temporary shock load is applied frequently the efficiency of reactor may be disadvantageous as well as the wash-out of sludge will be increased by decreasing the size to the accumulated frequency of granular sludge and the size with maximum frequency.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.7-11
• /
• 2003

This study investigate the hydration heat history with variation of surface insulating material in cold weather concreting. According to the results, the temperature of concrete lowers below zero in 24hours, so early frost damage occurs in the case of exposure and 1 fold bubble sheet, but the lowest temperature keeps above zero, so a adiabatic effect is very favorable in the case of double bubble sheet and 부직포. Compressive strength of core specimen at 7 and 28 days is highest In the case of double bubble sheet and 부직포. But, considering convenience of construction and economical efficiency, it is thought that the most effective surface insulating material is 1 fold bubble sheet +blanket.

• Journal of the Semiconductor & Display Technology
• /
• v.3 no.1
• /
• pp.15-20
• /
• 2004

Through shallow trench isolation (STI) chemical mechanical polishing (CMP) tests, we investigated the dependence of pad surface temperature on the abrasive and additive concentrations in ceria slurry under varying pressure using blanket film wafers. The pad surface temperature after CMP increased with the abrasive concentration and decreased with the additive concentration in slurries for the constant down pressure. A possible mechanism is that the additive adsorbed on the film surfaces during polishing decreases the friction coefficient, hence the pad surface temperature gets lower with increasing the additive concentration. This difference in temperature was more remarkable for the higher concentration of abrasives. In addition, in-situ measurement of spindle motor was carried out during oxide and nitride polishing. The averaged motor current for oxide film was higher than that for nitride film, meaning the higher friction coefficient.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2003.12a
• /
• pp.122-125
• /
• 2003

We investigated the effect of the abrasive and additive concentrations in Nano ceria slurry on the pad surface temperature under varying pressure through chemical mechanical polishing (CMP) test using blanket wafers. The pad surface temperature after CMP increased with the abrasive concentration and decreased with increase of the additive concentration in slurries for the constant down pressure. A possible mechanism is that the additive adsorbed on the film surface during polishing decreases the friction coefficient, hence the pad surface temperature gets lower with increase of the additive concentration. This difference of temperature was more remarkable for the higher concentration of abrasives. In addition, in-situ measurement of spindle motor was carried out during oxide and nitride polishing. The averaged motor current for oxide film was higher than that for nitride film, which means the higher friction coefficient.