• Journal of Digital Contents Society
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• v.9 no.2
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• pp.213-223
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• 2008

This study attempted to analyze background and industrial difference of RO and SO. RO was launched for solving a problem of terrestrial broadcasting. After solving a problem of terrestrial broadcasting system, RO has played a roll as a local media. On the other hand, SO was launched by government's policy so SO has been protected and brought up by government. Because market of RO and SO is overlap and competitive, RO has been restricted by government for issuing new license and renewal of permission. Presently, environment of media has been changed very dramatically, so various niche media are needed for various customer's needs. In addition, local media are in trouble of playing a role as a public broadcasting service in Korea. Therefore, RO might be a good solution. In this study for the analysis of the user's needs a survey was conducted. This study shows possibility of RO's roll and function as a local media.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.251-257
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• 2014

This research is focused on coagulation and sand filtration process as a pretreatment of RO seawater desalination. RO systems require sufficient and reliable pretreatment process to produce superior quality of RO feedwater that can mitigate RO membrane fouling. This experiment was conducted to investigate the effectiveness of coagulation and filtration process under various experimental conditions including different coagulant dose, flocculation mixing intensity and time, turbidity, and filtration rate. The experimental results showed that the optimum pretreatment conditions resulting in lower SDI value suitable for RO feedwater were coagulation pH 6.5, raw water turbidity greater than 4 NTU, and media bed depth greater than 550 mm. However, flocculation mixing intensity, coagulant dose, and filtration rate relatively affected little on the filtration efficiency.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.407-414
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• 2013

Full scale livestock wastewater treatment plant (100 t/d) was constructed and operated to develop compact and cost effective treatment process for public plant as well as individual farm. Liquid form of livestock wastewater after belt press filter was treated through MBR/NF/RO. NF/RO brine water was mixed with livestock wastewater sludge and treated using denitrification, coagulation and air flotation process. Mixed effluent of NF/RO and air flotation meet public livestock wastewater treatment standard, BOD, T-N and T-P, 30 mg/L, 60 mg/L, 8 mg/L below, respectively. Condensed sludge of air flotation returned belt press filter. Dewatered cake contained 90% water and could be used fertilizer after mixing sawdust.

• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.178-185
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• 2016

This study was designed to develop and to qualify a coffee alternative beverage using a mixture of coffee beans and roasted black beans (Rhynchosia nulubilis). Therefore, the total isoflavone content (TIC), total phenol content (TPC), antioxidant activity, anti-inflammatory activity, NFATc1 (Nuclear factor of activated T-cells c1) expression in RANKL (receptor activator of nuclear factor kappa-B ligand)-stimulated RAW264.7 cells and sensory evaluation were measured for 5 different Cb (coffee bean)-RoS (roasted seomoktae) mixture extracts (Cb100RoS0, Cb75RoS25, Cb50RoS50, Cb25RoS75, and Cb0RoS100). Cb0RoS100 had the highest TIC ($516.83{\pm}36.61mg/100g$) and TPC ($18.11{\pm}1.77mg$ TAE/100 g) along with the highest antioxidant activity as measured by DPPH radical scavenging activity ($73.55{\pm}8.11%$) and ABTS radical scavenging activity ($63.27{\pm}7.27%$). Also, Cb0RoS100 showed the highest anti-inflammatory activity as measured by NO production ($13.57{\pm}2.21{\mu}M$) and PGE2 production ($3.25{\pm}0.21ng/mL$). The more the RoS ratio was increased in the mixtures of Cb-RoS, the more the NFATc1 protein expression was decreased in RANKL-stimulated RAW264.7 cells. In case of sensory evaluation, Cb50RoS50 had the highest scores for flavor, delicate flavor and overall quality, which were similar to those in Cb alone (Cb100RoS0). We suggest that the use of RoS replacement instead of Cb in/as a coffee alternative beverage may help to reduce the risk of caffeine-related bone loss and/or bone disease by effectively blocking NFATc1 expression in RANKL-stimulated RAW264.7 cells compared with Cb alone.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.1-10
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• 2000

An experimental study regarding the effect of emulsions on RO is presented. Heavy oil was added to the sea water and the distilled water separately and treated for 30 minutes by a homogenizer to make emulsions. For the case of the sea water without heavy oil the permeate decreased from the beginning of the experiment. Chloride and conductivity increased with time, due to the fouling occurring as the suspended solids in the sea water accumulated on the membrane surface. Rejection rate of salt was 99.6~99.7%. As for the sea water containing heavy oil, the permeate decreased slowly from the beginning of the experiment. This result was the same for the case of the sea water only. However. chloride and conductivity increased significantly when heavy oil was added. In the second experiment with sea water containing heavy oil, the operation time of RO was reduced considerably. With addition of oil, the chloride increased greatly, while the permeate reduced comparatively. In the experiment where emulsion of $0.3{\sim}0.8mg/{\ell}$ was supplied to RO. oil concentration was about 10ppb in the permeate at the end of the experiment. In case of the distilled water containing heavy oil. the conductivity increased. However. the permeate reduced to 30% compared to the case of the sea water containing heavy oil. The case of sea water containing heavy oil showed an opposite result, but the effect of the addition of oil on RO was significant. Oil caused fouling of the RO and the contamination of the whole system, and as the result the system could not be operated properly. As a result the membrane capacity, the amount and water quality of permeate deteriorated significantly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.351-357
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• 2022

A conventional seawater reverse osmosis (SWRO) and a forward osmosis (FO) and reverse osmosis (RO) hybrid process to produce 1,000 m³/d of fresh water, were designed and compared in terms of carbon emission. When FO was adapted for the osmotic dilution, the required pressure for RO decreases, and thus energy consumption decreases. The decrease in carbon emission by decreased energy consumption (up to -0.73 kgCO₂/m³ using coal as the energy source) was compared with the increase in carbon emission by the FO system (+0.16 kgCO₂/m³), which is a function of various factors such as the number of FO modules and energy consumption. The comparison revealed that the FO-RO process causes less carbon emission compared with the SWRO process when the energy sources are coal and oil. However, if energy sources with low carbon emission such as solar, wind, and nuclear energy are selected, the carbon emission of the FO-RO process becomes higher than that of the SWRO process. This implies that the type of energy source is a key factor to determine the necessity of the FO-RO process from the aspect of carbon emission.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.1
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• pp.73-80
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• 2004

This study investigated the phenomena of membrane fouling by NOM and the effect of the fouling on removal of micro-pollutants. NOM has a great effect on decline of permeate flux. Permeate flow rate was reduced by 88% in RO and 34.8% in NF for 323hr operation period. Removal rate of $UV_{254}$, is 87.4% in RO and 78.5% in NF and removal rate of DOC is 42.7% in RO and 32.9% in NF for 2mg/l humic acid. Removal efficiency of the micro-pollutants by the RO and NF membranes fouled by humic acid was mostly lower than that by the new membrane. The concentration polarization which affects the flux and the rejection was thought to occur in the active layer of the membrane, as the membrane was getting fouled.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1289_1290
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• 2009

유해물질 제한지침(Restriction of Hazardous Substances Directive)은 유럽연합(EU)에서 시행되며 해로운 물질을 사용한 전자제품이나, 전기기기를 제한하는 지침이다. 일반적으로 RoHS(알오에이치에스)라고 적는다. 2003년 2월에 WEEE(Waste Electrical and Electronic Equipment)에 의해 제정 공포되고 2006년 7월 1일 발효되어 카드뮴, 납, 수은, 6가 크롬, 브롬계 난연제(PBBs, PBDEs)의 사용이 금지되었다. 중국에서도 이와 비슷한 제도 RoHS(일명 China RoHS)를 시행을 하고 있어 유럽에서 정한 6가지 품목과 규제 대상이 아니지만, 과학기기나 의학장비도 중국의 RoHS에는 규제 대상에 포함되어 있다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.42-48
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• 1992

RoA is an important figure of merits for estimating the performance of p-n junction infrared detectors. This paper presents the tunneling current contribution to RoA of $Hg_{1-x}Cd_{x}$Te n$^{+}$-p juction photodiodes. Then, a diffusion model, a thermal generation-recombination model, an indirect tunneling model via trap, and a band-to-band direct tunneling model are considered to calculate RoA. Using these models, RoA depending on temperature, doping concentration, and mole fraction is calculated. Also from these results, under various operating conditions the dominant dark current mechanisms cna be understood.

• Journal of information and communication convergence engineering
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• v.13 no.3
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• pp.167-171
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• 2015

A radio over fiber (RoF) system is a kind of analog optical transmission system and considered as a strong candidate for the next-generation fronthaul link in the future mobile network. In RoF systems, nonlinearity compensation is essential to increase the link capacity. In this paper, we propose a nonlinearity detection and compensation scheme using a monitoring channel in RoF systems. A monitoring channel is added at the transmitter site and used for transmitting a reference signal in an RoF transmission. The nonlinearity in the RoF transmission is detected by comparing the received monitoring signal and the original reference signal at the receiver site. Finally, the nonlinearity is compensated at the receiver by giving the reverse function of the detected nonlinearity. Our results show that the proposed scheme can almost remove the error vector magnitude degradation induced by the nonlinearity in the RoF system.