• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.237-240
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• 2005

The demand of micro electrical mechanical system (MEMS) bio/chemical sensor is rapidly increasing. To prevent the contamination of sensing area, a filtration system is required in on-chip total analyzing MEMS bio/chemical sensor. A nano-filter was mainly applied in some application detecting submicron feature size bio/chemical products such as bacteria, fungi and so on. We suggested a simple nano-filter fabrication process based on replication process. The mother pattern was fabricated by holographic lithography and reactive ion etching process, and the replication process was carried out using polymer mold and UV-imprinting process. Finally the nano-filter is obtained after removing the replicated part of metal deposited replica. In this study, as a practical example of the suggested process, a nano-dot array was replicated to fabricate nano-filter fur bacteria sensor application.

• Membrane Journal
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• v.16 no.4
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• pp.268-275
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• 2006

Novel SILEMs were prepared by multi-stage phase separation process combined by the low temperature phase separation (LTPS) and the high temperature phase separation (HTPS) using room temperature ionic liquids (RTILs) which have a high ionic conductivity. PVDF and imidazolium series ionic liquids were used as membrane material and electrolyte, respectively. To study the ion conducting properties, the SILEMs were tested using LCR meter at temperature controlled from 30 to $130^{\circ}C$. Under humid conditions, with increasing temperature from 30 to $100^{\circ}C$, the ion conductivity of the cast $Nafion^{(R)}$ membrane increased linearly, but then started to decrease after $100^{\circ}C$. However, in the case of the SILEMs, with increasing operating temperature, the ion conductivity increased. Also, the ion conductivity behaviors of the SILEMs were almost same, regardless of humidity. The ion conductivity of the SILEMs was $2.7{\times}10^{-3}S/cm$ and increased almost linearly up to $2.2{\times}10^{-2}S/cm$ with increasing temperature to $130^{\circ}C$. The effects of an inorganic filler on the physical properties of the SILEMs were studied using the $SiO_2$. The addition of $SiO_2$ could improve the mechanical strength of the SILEMs, though the ionic conductivity was decreased slightly.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1760-1768
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• 2019

The use of lignocellulosic biomass such as rice straw can help subsidize the cost of producing value-added chemicals. However, inhibitory compounds, such as phenolics, produced during the pre-treatment of biomass, hamper the saccharification process. Laccase and electrochemical stimuli are both well known to reduce phenolic compounds. Therefore, in this study, we implemented a bioelectrochemical detoxification system (BEDS), a consolidated electrochemical and enzymatic process involving laccase, to enhance the detoxification of phenolics, and thus achieve a higher saccharification efficiency. Saccharification of pretreated rice straw using BEDS at 1.5 V showed 90% phenolic reduction (Ph_r), thereby resulting in a maximum saccharification yield of 85%. In addition, the specific power consumption when using BEDS (2.2 W/Kg Ph_r) was noted to be 24% lower than by the electrochemical process alone (2.89 W/kg Ph_r). To the best of our knowledge, this is the first study to implement BEDS for reduction of phenolic compounds in pretreated biomass.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.18-18
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• 1996

This paper reviews some of the most prominent and promising areas of chemical process control both in relations to batch and continuous processes. These areas include the modeling, optimization, control and monitoring of chemical processes and entire plants. Most of these areas explicitly utilize a model of the process. For this purpose the types of models used are examined in some detail. These types of models are categorized in knowledge-driven and datadriven classes. In the areas of modeling and optimization, attention is paid to batch reactors using the Tendency Modeling approach. These Tendency models consist of data- and knowledge-driven components and are often called Gray or Hybrid models. In the case of continuous processes, emphasis is placed in the closed-loop identification of a state space model and their use in Model Predictive Control nonlinear processes, such as the Fluidized Catalytic Cracking process. The effective monitoring of multivariate process is examined through the use of statistical charts obtained by the use of Principal Component Analysis (PMC). Static and dynamic charts account for the cross and auto-correlation of the substantial number of variables measured on-line. Centralized and de-centralized chart also aim in isolating the source of process disturbances so that they can be eliminated. Even though significant progress has been made during the last decade, the challenges for the next ten years are substantial. Present progress is strongly influenced by the economical benefits industry is deriving from the use of these advanced techniques. Future progress will be further catalyzed from the harmonious collaboration of University and Industrial researchers.

• Journal of the Korean Institute of Gas
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• v.7 no.3 s.20
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• pp.24-31
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• 2003

To operate process plant safely and economically, process monitoring is very important. There are a great number of data acquired through distributed control system and process information system. Fault monitoring is the task with difficulties owing to not only the huge amount of data, but also nonlinearity of chemical processes. In this research, the program, REFA, based on PCA and functional link associative neural network has developed. REFA has better learning capabilities, generalization abilities, and shorter learning time than existing neural network programs. In this work its usefulness has proven by application to Tennessee Eastman process.

• Textile Coloration and Finishing
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• v.30 no.3
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• pp.168-179
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• 2018

The modified surface of specialty carbon black(SCB) is one of the main technical factors for producing a uniform color and stable dispersion. In this work, the carboxylation or sulfonation process of SCB was used to improve the dispersive properties of hydrophilic solvents such as 1,6-hexanediol and propylene glycol monomethyl ether acetate(PGMEA). The results showed that the color strength of SCB DC2500G changed little with a range of 0.128~0.941(${\Delta}E$) compared to other SCB DC2500G material. In contrast, in the case of SCB EG410, there was a uniform color value with a range of 0.144~0.252(${\Delta}E$). Also, in our experiments, a modified SCB was confirmed by printing ink material as a melt coating paper. It may be possible that the SCB EG410 material can be advantageous as a gravure ink product. Finally, the modified SCB obtained from this research will have a large impact on the industry as a potential material for toners, paint, rubber, fillers, and other carbon black additives.

• Korean Journal of Materials Research
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• v.27 no.9
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• pp.501-506
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• 2017

Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with $15{\sim}20{\mu}m$ dia. of $Al_2O_3$ media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.606-611
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• 2016

Carbon dioxide injection is a widely known method of enhanced oil recovery (EOR). It is critical for the $CO_2$ EOR that the injected $CO_2$ to reach a condition fully miscible with oil. To reach the miscible point, a certain level of pressure is required, which is known as minimum miscibility pressure (MMP). In this study, a MMP prediction method using a process simulator is proposed. To validate the results of the simulation, those are compared to a slim tube experiment and several empirical correlations of previous literatures. Aspen HYSYS is utilized as the process simulator to create a model of $CO_2$/crude oil encounter. The results of the study show that the process simulator model is capable of predicting MMP and comparable to other published methods.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.61-66
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• 1998

Glycolipids produced by Pseudomonas aeruginosa YPJ-80 were characterized by chromatographic and spectorscopic techniques as a mixture of two rhamnolipids. For recovery of glycolipids from the culture broth, various isolation methods including ultrafiltration, adsorption and solvent extraction were compared. Ultrafiltration showed the best results in terms of glycolipids recovery. Further purification for spectroscopic analysis was carried out by adsorption chromatography and preparative thin layer chromatography. From the spectroscopic analysis, such as IR spectroscopy. FAB-MS, 1H-NMR and 13C-NMR and hydrolysis analysis, the glycolipids were identified as L-${\alpha}$-rhamnopyranosyl-${\beta}$-hydroxydecanoly-${\beta}$-hydroxydecanoate and 2-O-${\alpha}$-L-rhamnopyranosyl-${\alpha}$-L-rhamnopyranosyl-${\beta}$-hydroxydecanoyl-${\beta}$-hydroxydecanoate. Monorhamnolipid and dirhamnolipid lowered the surface tension of water to 28.1 mN/M and 29.3 mN/m, respectively.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.65-70
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• 1997

The effects on the enzymatic hydrolysis of waste paper treated with physical or chemical treatment were investigated. To gain the higher saccharification rate, physical or chemical treatment are necessary in enzymatic conversion process of waste paper. The major deterrents to the effective utilization of waste paper for enzymatic conversion process are phenolic compounds, cellulose crystallinity and coating materials. In the enzymatic hydrolysis of waste paper, the deterrents through enzymatic conversion process can be eliminated by the physical or chemical treatment. This study was performed to obtain the optimal condition for enzymatic conversion process of non-treated waste paper and to review effects on enzymatic conversion process of waste paper treated with physical or chemical methods. In the aspect of saccharification rate, waste paper treated with 1.5% sodium hypochlorite was the most effective and in physical treatment methods, multi-stage treatment(autohydrolysis+refining treatment) was more effective than the other physical treatment.