• Title/Summary/Keyword: Oxygen membrane

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Recent Trend of Ultra-Pure Water Producing Equipment

  • Motomura, Yoshito
    • Proceedings of the Membrane Society of Korea Conference
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    • 1996.06a
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    • pp.121-147
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    • 1996
  • Since 1980, the water quality of ultra-pure water has been rapidly improved, and presently ultra-pore water producing equipment for 64Mbit is in operation. Table 1 shows the degree of integration of DRM and required water quality exlmple. The requirements of the ultra-pure water for 64Mbit are resistivity: 18.2 MQ/cm or higher, number of particulates: 1 pc/ml or less (0.05 $\mu$m or larger). bacteria count: 0.1 pc/l or less. TOC (Total Organic Carbon, index of organic snbstance) : 1ppb or less, dissolved oxygen: 5ppb or less, silica: 0.5ppb or less, heavy metal ions: 5ppb or less. The effect of metals on the silicon wafer has been well known, and recently it has been reported that the existence of organic substance in ultra-pure water is closely related to the device defect, drawing attention. It is reported that if organic substance sticks to the natural oxidation film, the oxide film remaims on the organic substance attachment in the hydrofluoric acid treatment (removal of natural oxidation film). The organic substance forms film on the silicon wafer, and harmful elements such as metals and N.P.S., components contained in the organic substance and the bad effect due to the generatinn of silicon carbide cannot be forgotten. In order to remove various impurities in raw water, many technological develoments (membrane, ion exchange, TOC removal, piping material, microanalysis, etc.) have been made with ultra-pure water producing equipment and put to practical use. In this paper, technologies put to practical use in recent ultra-pure vater producing equimeut are introduced.

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Automatic On-line BOD Measurement System Using A Microbial Membrane Electrode (미생물막 전극을 이용한 BOD 자동화 측정장치)

  • Oh, Hyuk;Kim, Hai Dong
    • Analytical Science and Technology
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    • v.8 no.3
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    • pp.335-340
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    • 1995
  • Automatic biochemical oxygen demand(BOD) measurement system has heen developed using a microbial membrane electrode, prepared from Bacillus subtilis and polyvinyl alcohol(PVA). The automatic BOD measurement system showed a linear response curve up to BOD 60 ppm using a glucose/glutamic acid standard solution, and all the BOD measurement processes are carried out automatically to calculate BOD whithin 10 min after each sample injection. The response times of the microbial electrode was 5 minutes with a 5 min recovery time between measurements and the relative error of the BOD estimation was within 10%.

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Development of the ultra/nano filtration system for textile industry wastewater treatment

  • Rashidi, Hamidreza;Sulaiman, Nik Meriam Nik;Hashim, Nur Awanis;Bradford, Lori;Asgharnejad, Hashem;Larijani, Maryam Madani
    • Membrane and Water Treatment
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    • v.11 no.5
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    • pp.333-344
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    • 2020
  • Advances in industrial development and waste management over several decades have reduced many of the impacts that previously affected ecosystems, however, there are still processes which discharge hazardous materials into environments. Among industries that produce industrial wastewaters, textile manufacturing processes play a noticeable role. This study was conducted to test a novel continuous combined commercial membrane treatment using polyvinylidene fluoride (PVDF), ultrafiltration (UF), and polyamide (PA) nanofiltration (NF) membranes for textile wastewater treatment. The synthetic textile wastewater used in this study contained sodium silicate, wax, and five various reactive dyes. The results indicate that the removal efficiency for physical particles (wax and resin) was 95% through the UF membrane under optimum conditions. Applying UF and NF hybrid treatment resulted in total effective removal of dye from all synthetic samples. The efficiency of sodium silicate removal was measured to be between 2.5 to 4.5% and 13 to 16% for UF and NF, respectively. The chemical oxygen demand in all samples was reduced by more than 85% after treatment by NF.

Olefin/Paraffin Separation though Facilitated Transport Membranes in Solid State

  • Hong, Seong-Uk;Won, Jong-Ok;Hong, Jae-Min;Park, Hyun-Chae;Kang, Yong-Soo
    • Proceedings of the Membrane Society of Korea Conference
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    • 1999.07a
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    • pp.15-18
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    • 1999
  • A simple mathematical model for facilitated mass transport through a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation. The current model demonstrates that the facilitation factor depends on the extent of concentration fluctuation, the time scale ratios of diffusion to chemical reaction and the ratio of the carrier concentration to the solute solubility in matrix. The model was examined against the experimental data on oxygen transport in membranes containing metallo-porphyrin carriers, and the agreement was exceptional (within 10% error). The basic concept of this approach was applied to separate olefin from olefin/paraffin mixtures. A proprietaty carrier, developed here, resulted that the selectivity of propylene over propane was more than 120 and the propylene permeance exceed 40 gpu.

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Current Status of One-Dimensional Nanostructured Catalysts for Polymer Electrolyte Membrane Fuel Cell (고분자 전해질 막 연료 전지용 1차원 나노 구조 촉매의 연구 현황)

  • Jeon, Kiung;Jung, Yeon Sik
    • Ceramist
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    • v.21 no.4
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    • pp.331-348
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    • 2018
  • With the expectation to overcome the problem of increasing energy consumption, polymer electrolyte membrane fuel cells are getting more attention as a promising environmentally friendly and sustainable next-generation energy conversion system. In spite of the rapid improvement of polymer electrolyte membrane fuel cells(PEMFCs), there are several critical issues still need to be resolved for practical commercialization. Out of the many issues, the main hurdle comes from oxygen reduction reaction(ORR), thus development of efficient ORR electrocatalysts is the main key for enhancing PEMFC performance. Among various catalysts, 1D nanostructured catalyst is a promising candidate because it holds many advantages that come from nanostructuring while supplementing the disadvantages of other nanostructures such as nanoparticles(0D) or gyroids(3D). This review focused on diverse 1D nanostructures and talks about their advantages as catalyst for ORR. Different 1D nanostructures will be introduced while applying the structures to different materials system showing the prospects of 1D nanostructures for improving PEMFC.

Study of Voltage Loss on Polymer Electrolyte Membrane Fuel Cell Using Empirical Equation (Empirical Equation을 이용한 고분자전해질 연료전지의 전압 손실에 대한 연구)

  • Kim, Kiseok;Goo, Youngmo;Kim, Junbom
    • Applied Chemistry for Engineering
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    • v.29 no.6
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    • pp.789-798
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    • 2018
  • The role of empirical equation to predict the performance of polymer electrolyte membrane fuel cell is important. The activation, ohmic and mass transfer losses were separated in a polarization curve, and the curve fitting according to each region was performed using Kim's model and Hao's model. Changes of each loss were compared according to operation variables of the temperature, pressure, oxygen concentration and membrane thickness. The existing model showed a good fitting convergence, but less fitting accuracy in the separated loss region. A new model using the convergence coefficient was suggested to improve the accuracy of performance prediction of fuel cells of which results were demonstrated.

Effect of aqueous Nigella sativa extract on the functional parameters of post-thaw human spermatozoa during vitrification

  • Nasiri, Zohreh;Ghorbani, Fatemeh;Seify, Mohammad;Sharbati, Aysan
    • Clinical and Experimental Reproductive Medicine
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    • v.49 no.2
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    • pp.110-116
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    • 2022
  • Objective: Sperm vitrification leads to the production of reactive oxygen species (ROS) that can damage the functional parameters of sperm. The present study aimed to investigate the antioxidant effect of Nigella sativa extract on motility, plasma membrane function, mitochondrial membrane potential (MMP), DNA damage, and intracellular ROS production. Methods: A total of 20 sperm samples were used. Samples were divided into six experimental groups, including groups with aqueous extract from N. sativa seeds at concentrations of 1% to 6%, a cryopreserved control group, and a fresh control group. Results: Statistical analysis showed significantly higher total sperm motility at concentrations of 3% to 6% than in the vitrified semen control group. Additionally, progressive motility and all motion characteristics at all concentrations were significantly higher than in the vitrified semen control group. The presence of N. sativa seed extract also improved the quality of the sperm parameters assayed in all experimental groups (1%-6%; intracellular ROS production, DNA damage, MMP, and sperm membrane function) compared to the control group. Conclusion: Higher concentrations of N. sativa led to improvements in all sperm parameters and sperm quality. These findings indicate that N. sativa seed extract is effective for improving the quality of sperm after vitrification.

Improved adsorption performance of heavy metals by surface modification of polypropylene/polyethylene media through oxygen plasma and acrylic acid

  • Hong, Jeongmin;Lee, Seungwoo;Ko, Dongah;Gwon, Eunmi;Hwang, Yuhoon
    • Membrane and Water Treatment
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    • v.11 no.3
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    • pp.231-235
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    • 2020
  • Industrialization and modern developments have led to an influx of toxic heavy metals into the aquatic environment, and the accumulation of heavy metals has serious adverse effects on humans. Among the various heavy metal treatment methods, adsorption is very useful and frequently used. Plastic materials, such as polypropylene and polyethylene, have been widely used as filter media due to their mechanical and chemical stability. However, the surface of plastic material is inert and therefore the adsorption capability of heavy metals is very limited. In this study, granular media and fiber media composed of polypropylene and polyethylene are used, and the surface modification was conducted in order to increase adsorption capability toward heavy metals. Oxygen plasma generated hydroxyl groups on the surface of the media to activate the surface, and then acrylic acid was synthesized on the surface. The grafted carboxyl group was confirmed by FT-IR and SEM. Heavy metal adsorption capability of pristine and surface modified adsorbents was also evaluated. Overall, heavy metal adsorption capability was increased by surface modification due to electrostatic interaction between the carboxyl groups and heavy metal ions. Fibrous PP/PE showed lower improvement compared to granular PP media because pore blockage occurred by the surface modification step, thereby inhibiting mass transfer.

Hyperoside Protects Cells against Gamma Ray Radiation-Induced Apoptosis in Hamster Lung Fibroblast

  • Piao, Mei Jing;Kim, Ki Cheon;Cho, Suk Ju;Chae, Sungwook;Kang, Sam Sik;Hyun, Jin Won
    • Natural Product Sciences
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    • v.19 no.2
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    • pp.127-136
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    • 2013
  • Ionizing radiation, including that evoked by gamma (${\gamma}$)-rays, induces oxidative stress through the generation of reactive oxygen species, resulting in apoptosis, or programmed cell death. This study aimed to elucidate the radioprotective effects of hyperoside (quercetin-3-O-galactoside) against ${\gamma}$-ray radiation-induced apoptosis in Chinese hamster lung fibroblasts, V79-4 and demonstrated that the compound reduced levels of intracellular reactive oxygen species in ${\gamma}$-ray-irradiated cells. Hyperoside also protected irradiated cells against DNA damage (evidenced by pronounced DNA tails and elevated phospho-histone H2AX and 8-oxoguanine content) and membrane lipid peroxidation. Furthermore, hyperoside prevented the ${\gamma}$-ray-provoked reduction in cell viability via the inhibition of apoptosis through the increased levels of Bcl-2, the decreased levels of Bax and cytosolic cytochrome c, and the decrease of the active caspase 9 and caspase 3 expression. Taken together, these results suggest that hyperoside defend cells against ${\gamma}$-ray radiation-induced apoptosis by inhibiting oxidative stress.

Effects of Flavonoids of Ginseng Leaves on Erythrocyte Membranes against Singlet Oxygen Caused Damage (일중항 산소($^1$O$_2$)에 의한 적헐구막 손상에 미치는 인삼잎 플라보노이드의 영향)

  • Soo-Nam Park;San
    • Journal of Ginseng Research
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    • v.14 no.2
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    • pp.191-199
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    • 1990
  • It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifolin and kaempferol from Ginseng leaves on singlet oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated. Each flavonoid aglycone (5-50$\mu$M) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging $^1O_2$ and free radicals Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by $^1O_2$. The $^1O_2$ and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by $^1O_2$ and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micells or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed.

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