• Journal of Institute of Control, Robotics and Systems
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• v.8 no.10
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• pp.833-841
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• 2002

We develope a model that can manipulate the reflux ratio of a batch distillation process in real time for optimal operations. Firstly, reflux ratio decision model for batch distillation unit was developed using the simple short-cut method. Secondly, more detailed rigorous method was applied to improve the accuracy of the model. Based on these models, operational strategies for the optimal reflux ratio was proposed. The results are illustrated with suitable examples and compared with the results using commercial simulator.

• Applied Biological Chemistry
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• v.37 no.1
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• pp.9-13
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• 1994

Baikhaju, the traditional Korean rice wine was brewed and distilled at various conditions-at different pressure (760, 460, 260 mmHg), different reflux ratio (3.1 : 1, 1 : 1) and different column conditions (packed and unpacked), and distillation operation was investigated. The sample wine, Baikhaju showed alcohol content of 14.2%, acidity 8.3 (g/100 ml), ethyl acetate 49 ppm, fusel oil 657 ppm. As the distillation was proceeded, alcohol concentration of distillate was decreased and that was higher in atmospheric pressure rather than reduced pressure. When the pressure was increased, the slope showed the relation of alcohol concentration between still liquid and vapour was increased, and also as the reflux ratio was increased, alcohol concentration of distillate was increased, and that was 0.56 mole at the reflux ratio 3.1 : 1 at atmospheric pressure, where 0.54 mole at 1 : 1 reflux ratio. As the distillation was proceeded, the rate of distillation was decreased, and that was higher values in the reduced pressure than atmospheric pressure. The maximum value (0.14 ml/s) of rate of distillation was observed in the packed column at 260 mmHg. As the reflux ratio was increased, the rate of distillation was decreased, and that was 0.05 ml/sec at reflux ratio 3.1 : 1 at atmospheric pressure, where 0.06 ml/sec at 1 : 1 reflux ratio.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.941-946
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• 1992

Three different reflux policies are compared for a batch distillation process in which a fixed recovery with a given average purity of the distillate is required ; the first, for the constant distillate purity ; the second, for the constant reflux ratio ; finally, for the optimal reflux policy which gives the minimum operation time. The optimal reflux policy was obtained using pontryagin's maximum principle. Througy the numerical simulations for the three different binary mixtures, it was found that the time advantage of the optimal reflux operation over the constant overhead composition operation varies form 10.0 to 22.4% and the advantage over the constant reflux operation varies from 1106 to 36.6% in the three cases considered.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.322-326
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• 1997

The condensate in a single vertical reflux condenser with a tube of the large L/D ratio could carried over in both ways of fill-and-dump and the annular occurrent to steam flow. From the experimental observation made, a theoretical model based on the lumped parameter method is made to understand the dynamics of the reflux condenser. The present model predicts well the time period of fill-and-dump model and the natural vibrational frequency of the water column. This could be a first step to understand the complex phenomena in the reflux condenser such as itd improved thermal performance due to the well controlled pulsation in steam flow and the tube-to tube effect in the multi tube reflux condenser.

• Membrane and Water Treatment
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• v.4 no.4
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• pp.251-263
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• 2013

The internal reflux effect on dialysis through the retentate phase of a countercurrently cross-flow rectangular module is investigated. Theoretical analysis of mass transfer in cross-flow devices with or without recycling is analogous to heat transfer in cross-flow heat exchangers. In contrast to a device without reflux, considerable mass transfer is achievable if cross-flow dialyzers are operated with reflux, which provides an increase in fluid velocity, resulting in a reduction in mass-transfer resistance. It is concluded that reflux can enhance mass transfer, especially for large flow rate and feed-concentration operated under high reflux ratio.

• Korean Journal of Organic Agriculture
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• v.30 no.1
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• pp.75-87
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• 2022

Reflux esophagitis (RE) is a gastroesophageal reflux disease (GERD) caused by repeated reflux of gastric acid into the esophagus. The present study investigated the protective effect of natural mineral water on esophageal injury induced by gastric acid reflux. The cytotoxicity of mineral water was confirmed using Cell viability, proliferation and cytotoxicity assay kit. The protective effect of mineral water on esophageal injury was investigated in RE rat model. The results showed that no cytotoxicity of mineral water was observed in RAW264.7 cells. Mineral water decreased the ratio of esophageal damage, inhibited the increase of inflammatory-protein expression levels and increased the mucosa protection and tight junction proteins expression level in RE control rat. The results suggest that mineral water may have the potential to protect esophageal damage caused by gastric acid reflux and the potential to alleviate reflux esophagitis.

• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.349-359
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• 2020

Gastroesophageal reflux disease (GERD) is a disease that stomach contents continually refluxing, and is currently on the rise worldwide. The purpose of this study is to find natural materials that can reduce side effects and effectively treat chronic acid reflux esophagitis (CARE), one of GERD. First, the antioxidant activity was confirmed by varying the mixing ratio of Coptidis Rhizoma and Evodiae Fructus, which are effective against chronic reflux esophagitis. After, animal experiments were conducted using a 1:1 (CE) and 1:2 (CEE) combination ratio of Coptidis Rhizoma and Evodiae Fructus, which had the best antioxidant efficacy. Gross lesion of esophageal mucosa after CE or CEE treatment showed a superior enhancement compared with that of CARE control rats. Additionally, its inhibited MAPK phosphorylation and led NF-κB inactivation through the suppression of IκBα phosporylation by regulating Nrf2/Keap-1, and NF-κB inactivation induced reduced protein expressions including inflammatory mediators and cytokines. Moreover, its improved esophageal barrier function through upregulating protein expressions of tight junction protein, whereas downregulating protein expressions of MMPs. Taken together, a mixture of Coptidis Rhizoma and Evodiae Fructus can attenuate the esophageal mucosal ulcer by inhibiting MAPK and NF-κB pathway, and upregulating proteins associated with tight junction.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.420-425
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• 2014

Esophageal reflux of gastric contents causes esophageal mucosal damage and inflammation. Recent studies show that oxygen-derived free radicals mediate mucosal damage in reflux esophagitis (RE). Chlorogenic acid (CGA), an ester of caffeic acid and quinic acid, is one of the most abundant polyphenols in the human diet and possesses anti-inflammatory, antibacterial and anti-oxidant activities. In this context, we investigated the effects of CGA against experimental RE in rats. RE was produced by ligating the transitional region between the forestomach and the glandular portion and covering the duodenum near the pylorus ring with a small piece of catheter. CGA (10, 30 and 100 mg/kg) and omeprazole (positive control, 10 mg/kg) were administered orally 48 h after the RE operation for 12 days. CGA reduced the severity of esophageal lesions, and this beneficial effect was confirmed by histopathological observations. CGA reduced esophageal lipid peroxidation and increased the reduced glutathione/oxidized glutathione ratio. CGA attenuated increases in the serum level of tumor necrosis factor-${\alpha}$, and expressions of inducible nitric oxide synthase and cyclooxygenase-2 protein. CGA alleviates RE-induced mucosal injury, and this protection is associated with reduced oxidative stress and the anti-inflammatory properties of CGA.

• Biomedical Science Letters
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• v.27 no.2
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• pp.77-87
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• 2021

Reflux esophagitis (RE) is a disease that stomach contents, stomach acid, and pepsin continually refluxing and is curently increasing worldwide. This study was conducted to find natural materials that can reduce side effects and effectively treat RE. Animal experiments were conducted with a 1:1 (EA1), 1:5 (EA5) ratio of Evodiae Fructus and Arecae Semen known to be effective against reflux esophagitis. As a result of confirming the total lesion of the esophageal mucosa after EA1 or EA5 treatment in reflux esophagitis animals, it showed superior improvement compared to the RE-control rats. In addition, by regulating the expression of MPO and NADPH oxidase, the activation of NF-κB was inhibited, and the expression of COX-1 and COX-2 was regulated. Moreover, its improved esophageal barrier function through regulating protein expressions of tight junction protein and MMPs/TIMPs. Taken together, a mixture of Evodiae Fructus and Arecae Semen can attenuate the damage to the esophageal mucosa that not only inactivationed the NF-κB through oxidative stress control, but also by regulating tight junctions and MMPs/TIMPs. This effect was more excellent in the 1:1 mixture (EA1) than in the Evodiae Fructus and Arecae Semen 1:5 mixture (EA5).

• Applied Chemistry for Engineering
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• v.21 no.6
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• pp.616-620
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• 2010

This study was performed to recycle Propylene Glycol Monomethyl Ether Acetate (PGMEA) from Liquid Crystal Display (LCD) industry emission as a waste organic solvent by using a multistage distillation column and tried to decide optimum reflux ratio. From the final experiment result, it was confirmed ; in case the sample A, the PGMEA purity is more than 98% and the moisture is less than 0.05%, on the other hand, in case the sample B, the PGMEA purity is more than 95% when the reflux ratio is 6 and the moisture is less than 0.01% (Refer to Table 1 for the contents of sample A and B). These values means fine level which can be adapted in the LCD manufacture, requiring more than 90% common purity of recycling level.