• Journal of the Semiconductor & Display Technology
• /
• v.15 no.4
• /
• pp.27-32
• /
• 2016

In recent years, various researches have been conducted to improve process yields in accordance with miniaturization of semiconductor. APC(Advanced Process Control) is considered one of the methods to increase in process yields. APC is a process control technology that maintains optimal process conditions and improves the reliability of results by controlling and formulating the relationship among the various process parameters and results. We built up an optical diagnostic system with a three-channel spectrometer. The system detects signals those represent the changes of specific emission peaks intensity versus each reference and converts it into MFC control signals to get back the changes to the reference state. Controlling the MFC continues until the specific peak intensity changes into the normal state. Through this device, we tested a APC automatically responding to process changes during the plasma process. We could control gas flow while sputtering process on going and improve uniformity of plasma intensity with this system. Finally, we have got results those enhance the plasma intensity non-uniformity to 7.7% from 15.5%. Also, found unexpected oxygen flow what is estimated to be come out from IGZO target.

• Korea-Australia Rheology Journal
• /
• v.21 no.2
• /
• pp.83-89
• /
• 2009

Coating process plays an important role in information technology such as display, battery, chip manufacturing and so on. However, due to complexity of coating material and fast deformation of the coating flow, the process is hard to control and it is difficult to maintain the desired quality of the products. Moreover, it is hard to measure the coating process because of severe processing conditions such as high drying temperature, high deformation coating flow, and sensitivity to the processing variables etc. In this article, the coating process is to be re-illuminated from the rheological perspectives. The practical approach to analyze and quantify the coating process is discussed with respect to coating materials, coating flow and drying process. The ideas on the rheology control of coating materials, pressure and wet thickness control in patch coating process, and stress measurement during drying process will be discussed.

• Journal of Environmental Science International
• /
• v.15 no.7
• /
• pp.659-667
• /
• 2006

This research aims at applicability of adsorption process in order to satisfy the restricted Effluent Quality Standards for dyeing wastewater. The dyeing wastewater treated by biological process with carrier imbedded microorganisms was directly applied to the activated carbon adsorption in Process A, The dyeing wastewater treated by Fenton oxidation for the effluent of biological process was applied to the adsorption in Process B. It was found that the optimum conditions of adsorption with granular activated carbon are $20^{\circ}C$ and 120 minutes for the batch experiment. Langmuir equation was fitted better than Freundlich equation to the experimental data. The breakthrough time of adsorption column was determined by color rather than $COD_{Mn}$ for both Process A and Process B. The results revealed that the breakthrough time of adsorption for two processes was extended by the treatment of Fenton oxidation for dyeing wastewater treated by biological treatment than the direct application of dyeing wastewater treated by the biological treatment. Adsorption process can be applied in order to meet the restricted Effluent Quality Standards for dyeing wastewater.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.3 s.116
• /
• pp.72-78
• /
• 2006

The extraction properties of the biological waste originated from the Tobacco industry were evaluated. The biological waste have been recycled and transformed into a valuable material, so called a reconstituted tobacco sheet(Recon) by the papermaking process. In this process, The mechanical extraction process, which divides the mixed raw material slurry into the soluble stock and the insoluble stock, could affect not only the quality of final Recon product but also the productivity of whole Recon making process. This study investigated the effects of the extraction process on the slurry properties in detail. In order to quantify the amounts of the solubles which resided in the insoluble fibers, the washing treatment of the stock before and after squeezing process was applied. The amounts of the residual solubles showed little changes according to each stage of the extraction process. The fractionation of the slurry showed the difference in the amount of soluble in the stock depending on the size of the biological waste. After the extraction process, the bigger size fiber portion contained about 19%(by weight) in soluble after pressing but the smaller size fiber portion 9% in soluble. The fractionation ratio of the stocks also was changed by the screw press process, which could demonstrate the physical effects of the mechanical extraction.

• Journal of Hydrogen and New Energy
• /
• v.28 no.4
• /
• pp.352-360
• /
• 2017

Polygeneration process is widely used to pursuit high efficiency by sharing electricity, utility, refrigeration and the utilization of product chemicals. In this paper, performance analysis of the 450 MW Class polygeneration process was conducted with various syngas generated from coal and biomass gasifier. WGSR and PSA process were employed for hydrogen production and separation. Process modeling and dynamic simulation was carried out, and the results were compared with NETL report. Net power of the polygeneration process was 439 MW considering power consumption. More than 90% of CO was converted at WGSR and the hydrogen purity of PSA was more than 99.99%.

• Korean Chemical Engineering Research
• /
• v.44 no.1
• /
• pp.16-22
• /
• 2006

Biological hydrogen production processes are more environment-friendly and less energy intensive than thermochemical and electrochemical processes. The biological process can be divided into two categories: photosynthetic hydrogen production and hydrogen production by dark fermentation. Photosynthetic process produces hydrogen mainly from water and reduces $CO_2$ simultaneously. Dark fermentation is a dark and anaerobic process that produces hydrogen by fermentative bacteria from organic carbon. The article presents a survey of biological hydrogen production processes.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.10
• /
• pp.1430-1437
• /
• 2021

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD₅₄₀ = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.

• Journal of Environmental Health Sciences
• /
• v.22 no.4
• /
• pp.69-76
• /
• 1996

Biological process have the potential to remove pollutants such as biodegradable organic fraction, $NH_3-N$, ABS, etc. that may be partially removed by conventional water treatment. This study was performed to evaluate four different processes of biological pretreatment as Biological Fluidized Bed(BFB), Biological Filter(BF), Rotating Biological Contactor(RBC) and Honey Comb(HC). In a given condition it proved out that BFB and BF are prospective biological pretreatment processes because they were the most effective on the removal of organic matter and ammonia. Preozonation of raw water for biological processes increased in biodegradable organic fraction about 10-40% with 0.425-0.85 mg $O_3/mg$ DOC.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.81-82
• /
• 2000

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.6
• /
• pp.837-848
• /
• 2006

This paper presents the test results of biological aerated filtration(BAF) process to replace activated sludge process by enhancing treated effluent quality and reducing the costs. In BAF process both BOD and SS compounds in wastewater are degraded and removed by biological reaction and filtration. Upflow BAF with expanded polypropylene media and downflow BAF with ceramic media were used to investigate the effects of hydraulic and organic loads on effluent quality. As a result, in BAF processes which has different media, upflow BAF reactor shows 5% higher efficiency than downflow BAF and this phenomena caused by backwashing methods and operational conditions. The results of influence factors analyzed by Factor Analysis Method in BOD and SS treatment efficiency are the size of media, hight of media bed and type of media. The quantitative effects of media size are 5.73% in TBOD, 5.78% in SBOD and 7.65% in TSS, so we confirmed the main factor is media size.