• Journal of Industrial Technology
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• v.25 no.A
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• pp.151-156
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• 2005

Auto exhausts and air pollution can become trapped in the cabin of vehicle, reducing the amount of oxygen available for breathing. Driver may feel sleepy, headaches, nausea, confusion, dizziness and lower levels of oxygen can damage the driver's general health. Consequently, oxygen generator purified oxygen into the car to help driver get the oxygen driver's body needs. In this study, in order to evaluate the oxygen generator performance, the samples that the various conditions(humidity(50%, 100%), flow and oxygen concentration) were examined. There were three types of oxygen generator; sample 1($2.5{\ell}/min$, $36%O_2$), sample 2($4.5{\ell}/min$, $41%O_2$) and sample 3($5{\ell}/min$, $39%O_2$). As the humidity increased from 50% to 100%, the oxygen concentration of the sample 1(36%), 2(41%) and 3(39%) was reduced $31%O_2$, $38%O_2$ and $38%O_2$, respectively. Also, the each sample measured that effect of human in car on oxygen concentration, if the oxygen concentration is one person in car, each sample of oxygen concentration was $20.8%O_2$, $23.7%O_2$ and $21.2%O_2$. From the above results, it was shown that oxygen generator for car, if the oxygen concentration is increased, effect of humidity is reduced, and that in the sample of supplying a high-rate of oxygen, the oxygen concentration is increased. It was suggested that effect of humidity on oxygen generator for car can be reduced according to the supply of oxygen.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.310-318
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• 1999

The concentration breakthrough curves were examined to predict mass transfer coefficients of nitrogen and oxygen in adsorption column for design data of PSA process. Experimental breakthrough curves for bulk gas flow were compared with theoretical simulation results. For quantitative analysis of the adsorption, coupled Langmuir isotherm was considered and LDF model was used to describe the mass transfer effect. In the experimental and theoretical results, it was found that mass transfer coefficient was not affected by flow rate but strongly affected by pressure. As a result of this tendency, mass transfer resistance in this system was proved to belong to the macropore diffusion controlling region and the mass transfer coefficients could be expressed by exponential functions of pressure change. The mass transfer coefficients for one component, nitrogen or oxygen, were successfully applied to breakthrough curves for bulk mixed gases. The experimental curves were reasonably in consistent with the theoretical curves and the error time was less than 5 percent.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.837-847
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• 2000

For the treatment of wastewaters generated from beer industry and petrochemical company with high organic and nitrogen contents, laboratory scale of A/O Pure-Oxygen Biofilm (POB) process was developed and studied by means of the comparative economic analysis with extended aeration process. When the wastewater of beer company was initially treated by the A/O POB process in the ranges of 70 to 150 mg TOC/L diluted with tap water, higher than 92% of TOC removal was accomplished in the all ranges. In case of petrochemical wastewater, the initial TOC removal was as low as 52%, though, it increased to 86% after 32 days of operation and also the TKN removal marked 71% after 27 days. Continuous high removal rates were monitored in both the TOC and TKN parameters during the experimental period. Due to the cost for PSA (Pressure Swing Adsorption) setting and biomass supporting media installation, the initial construction cost of A/O POB process was 2.9 times higher than that of extended aeration process. However, the advantages such as low sludge production, no need for sludge recycling and low energy consumption allow the A/O POB process to have 2.5 times lower operation and maintenance costs. Consequently, in the long term of operation, it is likely that A/O POB process would show higher performance as well as cost effectiveness compared to extended aeration process.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.38-41
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• 1994

막분리(membrane separation)법은 막 전후의 압력차, 농도차 등을 추진력(driving foroe)으로 하여 분리대상물질에 대한 막의 선택투과성 차이를 이용, 분리를 행하는 것이다. 이 분리법은 기존의 분리공정인 심냉법(cryogenic separation)과는 달리 상변환 공정이 필요없어 에너지가 적게 들고 또한 PSA(pressure swing adsorption)법에서와 같은 cycle 운전이 필요없어 연속적으로 분리가 가능하며 시스템도 간단하다. 최근 기체 막분리의 경우 수소 및 탄산가스의 회수정제, 공기중의 산소와 질소의 분리 등에 실용화되고 있다. 여기서는 공기중의 산소를 분리하여 30-40% 산소부화공기(oxygen enriched air)를 간편하게 제조할 수 있는 산소부화막장치와 연소장치에의 응용기술 및 연구결과에 대해 간략히 소개하고자 한다.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1534-1538
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• 2010

Fed-batch cultures of Hansenula polymorpha were studied to develop an efficient biosystem to produce recombinant human serum albumin (HSA). To comply with this purpose, we used a high-purity oxygen-supplying strategy to increase the viable cell density in a bioreactor and enhance the production of target protein. A mutant strain, H. polymorpha GOT7, was utilized in this study as a host strain in both 5-l and 30-l scale fermentors. To supply high-purity oxygen into a bioreactor, nearly 100% high-purity oxygen from a commercial bomb or higher than 93% oxygen available in situ from a pressure swing adsorption (PSA) oxygen generator was employed. Under the optimal fermentation of H. polymorpha with highpurity oxygen, the final cell densities and produced HSA concentrations were 24.6 g/l and 5.1 g/l in the 5-l fermentor, and 24.8 g/l and 4.5 g/l in the 30-l fermentor, respectively. These were about 2-10 times higher than those obtained in air-based fed-batch fermentations. The discrepancies between the 5-l and 30-l fermentors with air supply were presumably due to the higher contribution of surface aeration over submerged aeration in the 5-l fermentor. This study, therefore, proved the positive effect of high-purity oxygen in enhancing viable cell density as well as target recombinant protein production in microbial fermentations.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.123-130
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• 2005

Zeolite X adsorbents with large surface area were prepared for using oxygen PSA adsorbent. Selective adsorption performance of nitrogen on the synthesized zeolite X adsorbent was improved by the cation exchange of adsorbent. The zeolite X which had over $650m^2/g$ surface area was synthesized at the conditions of $SiO_2\;:\;Na_2O\;:\;H_2O\;:\;Al_2O_3$ = 2.5 : 3.5 : 150 : 1 mole ratio, $98^{\circ}C$ temperature and 18 h synthesized time in 50 L reactor. The metal ions Li, Ag, Ca, Br, Sr, etc. were investigated for ion exchange with zeolite X. Ag ion was showed the highest ion exchange rate among these metal ions and all metal ions were exchanged with Na ion at equivalent rate. Compared with the NaX adsorbent, the ion exchanged zeolite X adsorbent remarkably improved its adsorption performance of nitrogen at the conditions of $10{\sim}40^{\circ}C$ temperature and 0~9 atm pressure. At an equilibrium pressure under 0.5 atm, adsorption performance of nitrogen on the ion exchanged zeolite adsorbent increased in the order of Ag > Li > Ca > Sr> Ba > K, whereas at an equilibrium pressure over 1 atm showed in the order of Li > Ag > Ca > Sr > Ba > K. Nitrogen/oxygen separation factor of Li ion exchanged zeolite X adsorbent was 13.023 at the partial pressure of nitrogen/oxygen gas mixture similar to air and $20^{\circ}C$ adsorption temperature.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.213-217
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• 2021

Benign prostate hyperplasia (BPH) is one of the most common elderly disease, and because of prolonged incubation period and many side effects of medication or surgical interventions, the use of dietary phytochemicals is considered as an effective measure for prevention of BPH. The purpose of this study is to investigate the mechanism of inhibition effect for BPH by flavonoids such as baicalein and kaempferol. BPH cells were collected through biopsy from patients with PSA of 4 or higher, followed by primary culture. In vitro experiments were conducted to evaluate mitochondrial respiration, intracellular reactive oxygen species (ROS) level and expression of inflammatory markers, genes, and anti-oxidants. In conclusion, baicalein and kaempferol have been demonstrated to inhibit BPH through lowering ROS, thereby reducing inflammation triggers, and reduced inflammation. This study is expected to be helpful in the development of flavonoids that have a clinical effect on suppressing BPH.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.315-317
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• 2005

공기중의 산소농축 PSA 기술로 RPSA(Rapid Pressure swing adsorption)이 적용되므로 1979년 이후 소형의 의료용 장치로 상업화되기 시작하였다. 산소발생기(산소농축기)의 경우에도 개량형 RPSA방식을 적용한 기술로써 최근 우리나라도 고령화 사회가 되므로써 의료용으로 사용이 확대되고 있으며, 기타 작업장이나 특수 시설 등에서 사용이 증대되고 있다. 이러한 산소농축기의 핵심부품 중의 하나인 흡착탑의 경우 흡착제 구성 및 흡착탑의 구조에 의하여 성능이 좌우되고 있다. 현재 상용화된 제올라이트의 각 흡착제의 흡착특성을 도출하기 위하여 압력, 온도, 수분함유량에 따른 파과곡선을 측정하여 흡착탑의 단수에 따른 최적 단수를 도출하였다.

• Journal of Powder Materials
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• v.30 no.3
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• pp.233-241
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• 2023

In this study, we evaluated the effects of acid leaching on the properties of Cr powder synthesized using self-propagating high-temperature synthesis (SHS). Cr powder was synthesized from a mixture of Cr2O3 and magnesium (Mg) powders using the SHS Process, and the byproducts after the reaction were removed using acid leaching. The properties of the recovered Cr powder were analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), particle size analysis (PSA), and oxygen content analysis. The results show that perfect selective leaching of Cr is challenging because of various factors such as incomplete reaction, reaction kinetics, the presence of impurities, and incompatibility between the acid and metal mixture. Therefore, this study provides essential information on the properties under acidic conditions during the production of high-quality Cr powder using a self-propagating high-temperature synthesis method.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.28-38
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• 2023

Plant viruses are responsible for worldwide production losses of numerous economically important crops. The most common plant RNA viruses are positivesense single-stranded RNA viruses [(+)ss RNA viruses]. These viruses have small genomes that encode a limited number of proteins. The viruses depend on their host's machinery for the replication of their RNA genome, assembly, movement, and attraction to the vectors for dispersal. Recently researchers have reported that chloroplast proteins are crucial for replicating (+)ss plant RNA viruses. Some chloroplast proteins, including translation initiation factor [eIF(iso)4E] and 75 DEAD-box RNA helicase RH8, help viruses fulfill their infection cycle in plants. In contrast, other chloroplast proteins such as PAP2.1, PSaC, and ATPsyn-α play active roles in plant defense against viruses. This is also consistent with the idea that reactive oxygen species, salicylic acid, jasmonic acid, and abscisic acid are produced in chloroplast. However, knowledge of molecular mechanisms and functions underlying these chloroplast host factors during the virus infection is still scarce and remains largely unknown. Our review briefly summarizes the latest knowledge regarding the possible role of chloroplast in plant virus replication, emphasizing chloroplast-related proteins. We have highlighted current advances regarding chloroplast-related proteins' role in replicating plant (+)ss RNA viruses.