• Membrane Journal
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• v.18 no.1
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• pp.7-25
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• 2008

Sodium dodecyl sulfate, which was anionic surfactant, at a concentration higher than its critical micellar concentration was added to calcium solution for forming micelles. Then aggregates were formed by adsorption or binding of calcium ions on the surface of micelles, and gathering between them, and then rejected by two kinds of ceramic membranes to remove calcium ions. As result, rejection rates of calcium were higher than 99.98%. And in our experimental range the higher TMP trended to increase the resistance of membrane fouling ($R_f$), total permeate volume ($V_T$), dimensionless permeate flux ($J/J_o$) and permeate flux (J) because TMP was driving force. And we investigated effects of $N_2$-back-flushing time and filtration time, that was back-flushing period, during periodic $N_2$-back-flushing on ceramic membranes. As result, optimal BTs for NCMT-623l ($0.07{\mu}m$ pore size) and NCMT-7231 membrane ($0.10{\mu}m$) were 10 sec and 15 sec, respectively. Also, optimal FT was 5 min for both membranes, and the frequent $N_2$-back-flushing could decrease membrane fouling effectively. Then, the optimal conditions resulting from our experiments for synthetic calcium solution were applied to groundwater using as washing process of soymilk package. As result, rejection rates of calcium were higher than 99.98%.

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1011-1019
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• 1998

This work designed Sn-5%Pb-1.5%Ag-x%In solder alloy to develop the solder alloy with low Pb content. This solder alloy doesn't cause environmental pollution. and this study reviewed the probability of replacement of Sn-37%Pb solder as evaluation of melting range, wettability. microstructure, microhardne'ss, tensile strength, drossability of this new solder alloys. The level of international regulation in dissolution amount of Pb ion was 3ppm. But dissolution amount of Pb ion in Sn-5%Pb solder alloy confirmed not to threat the global environmental is 0.46ppm. The melting range of this solder alloy was $183-192^{\circ}C$. Also the range of solidification was very narrow within $5^{\circ}C$. The wettability was similar to Sn-37%Pb solder, and the effect of amount of In addition of wettability couldn't be founded. The probability of replacement in the melting range and wettability is very high. And microhardness of this solder alloy was 1.5 times of conventional type solder. Tensile strength of new solder alloys was a little high than that of conventional type solder. With increasing amount of In% addition, tensile strength was increased, but elongation was decreased. The solder alloy of l%In addition revealed AgSn and Pb on dendrite microstructure boundary, and $Ag_3Sn$, $Ag_3In$ and Pb were revealed on it at the solder alloy of 3% In addition. The drossability was superior to Sn-37%Pb solder alloy and the solder alloys of 2% In addition was not generated for 3hrs.

• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.134-144
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• 2010

In China, the enhancement of water services has become the most crucial issue confronted with the rapid urbanization and industrialization process. A huge financial gap to meet the demand for water infrastructure and need for adopting advanced operation technology precipitated the rapid growth of PPP over the last 10 years. Diverse schemes of PPP such as TOT, Divestiture, and Management Contract and Lease have been practiced. Local governments and private investors/operator have adjusted their objectives and strategies to avoid potential pitfalls behind BOT projects in China. However, current academic research outcomes do not properly reflect important issues of BOT projects or related case studies in China. This limitation has brought in the lack of assessment of important risks and success factors required for the improvement of the body of risk management. In this regard, this study uses the market analysis method to identify major schemes of PPP water projects and conducts case studies on five PPP projects to identify key risk and success factors in association with each different scheme. It is expected that the risk and success factors identified from the cases will be used as reference to Korean companies which plan to enter the Chinese water market.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.394-399
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• 2013

The recalcitrant hairs which are accumulated in the U-trap equipped to prevent the stench from the drainage produce the phenomenon of blocking the flow of water through the home drainage pathway. The chemical dissolution solutions commercially manufactured are excessively poured into U-trap to solve this blocking problem. In this study, the specially designed instrument was developed for the experiments to cut and crush the hairs of which main component are the recalcitrant keratin proteins. The performance of the instrument for cutting and crushing hairs was investigated using experimental methods. The cutting and weighing method was used in order to obtain the average length of a large amount of hairs cut by instrument. This method is relatively simple to measure the weight of cutting hairs to obtain the average length of the fibers, the values of average length showed not greater tolerances. Also the average cutting number was defined to evaluate the performance of the cutting and crushing instruments designed for this study. We were able to apply these evaluation methods to provide the criteria to obtain the optimal structure of instrument and proper operation time in the given experimental conditions. These experimental methods and results will provide the good example to design and to analyze the various device that can be used for cutting the fibers. The cutting and crushing instrument developed in this study showed the effective abilities to cutting the hairs. The general using the cuttting and crushing instrument at every home would be helpful to prevent water environmental pollution.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.143-150
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• 2013

The Honolulu Strategy is a framework document to address marine debris issue globally. The Fifth International Marine Debris Conference held in March 2011 and organized by NOAA and UNEP catalyzed the development of the Holonulu Strategy. Goals of the Strategy are to reduce the amount and impact of land-based, sea-based, and accumulated marine debris. A set of strategies for each goal were provided for education and awareness, legislation, and alternative technologies. The Strategy also lists indicators that could be used to evaluate outcomes of strategies. The adoption of the Honolulu Strategy by the international community has led the international organizations such as GPA, IMO, and CBD to strengthen their responses to the marine debris issue. UN has also set up specific actions that will be implemented until 2025 through its resolutions on marine debris. Recent global developments related to the marine debris issue might lead to a change in the character of the international marine debris management from the current soft law regime to a mandatory one. The Honolulu Strategy could provide a guideline when the Korean government formulates the Second Basic Plan for Marine Debris Management, especially with its prevention-oriented approaches, utilization of scientific policy development tools, and adoption of evaluation system using performance indicators.

• Analytical Science and Technology
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• v.25 no.3
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• pp.190-196
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• 2012

The human exposure of lead has usually detected the amount of lead in the whole blood, however, this method has a shortcoming to give the information on the short-term exposure to lead. In that sense, it is desirable to estimates the level of lead in plasma to draw the chronic bio-marker of lead exposure even though it is difficult to measure lead of several ng/L. An inductively coupled plasma-mass spectrometry (ICP-MS) method was developed for determining lead in plasma as the chronic bio-marker of lead of workers. To minimize the contamination of lead from the environment, we constructed class 1,000 clean room and compared the amount of floating dust before and after the operation of the clean room. The limit of detection (LOD) and the limit of quantification (LOQ) of lead in fetal bovine serum were 4.3 ng/L and 12.2 ng/L by NIOSH method (statistical calculation method) and 7.0 ng/L and 22.1 ng/L by signal/noise ratio, respectively. The accuracy was in a range of 92.3-101.3%, and the precision of the assay was less than 4% in the samples spiked in the concentration of 20 ng/L and 2,000 ng/L. The method was simple, reproducible and sensitive enough to permit reliable analysis of lead to the ng/L level in plasma and/or serum. The method was also useful for the biological monitoring of chronic exposure to lead.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.63-70
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• 2013

Experiments in a pilot-scale hybrid multi-stage unit system (HMUS) combination of ATAD and EGSB followed by SBR process for pig slurry treatment were conducted to demonstrate the feasibility of using autothermal thermophilic aerobic digestion (ATAD) and expended granular sludge bed (EGSB) followed by sequencing batch reactor (SBR) system. Contaminants in pig slurry with high organic matter, nitrogen (N) and phosphorus (P) content were completely removed in the combined process. The highest removal rate for CODcr among contaminants in the feed pig slurry was attained by about 43.3% in ATAD unit process. Also TS removal rate of 96.5% was attained and the highest in the next coagulation unit process. The highest removal rate of CODcr under operating parameter conditions of OLR(organic loading rate), 3-6Kg $COD/m^3{\cdot}day$ and line velocity, 1.5-4m/h was earned at 3days of HRT. The disinfection of pathogens was effective at 50,000mg/L of TS in ATAD unit process. Biogas production per organic removal was $2.3{\sim}8.5m^3/kgTS{\cdot}d$ (average $5.2m^3/kgTS{\cdot}d$) in EGSB unit process. The average removal rates of CODcr 71.7%, TS 64.1%, TN 45.9%, and TP 50.4% were earned in the intermittent aeration SBR unit process.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.228-233
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• 2010

About 55% of total energy is consumed in the industrial division. The industrial heat pump application will show magnificent energy saving effect as well as higher cost efficiency because of larger energy consuming volume of each facility and longer operation hour and higher stability against seasonal temperature change. Over 90% of dryer for industrial usage has hot wind heat source and hot wind dryer is the representative type covering 68.7% while its 30 ~ 50% lower heat efficiency causes lots of energy loss by exhaust air. Re-usage of exhaust air can improve energy efficiency of dryer because 68% heat energy or 78% of hot air lose in exhaust air. Therefore, high temperature heat pump dryer can be the best alternative. Comparing to the existing dryer with 30% ~ 50% energy efficiency, newly developing high temperature heat pump dryer will enhance energy efficiency up to 60% ~ 80% efficiency. In this paper, heat pump system for high temperature was designed, constructed and tested. The results have shown that system COPh is estimated as 3.3.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.130-136
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• 2008

목적: 방사성옥소 치료를 받는 많은 환자들이 장기간의 전처치와 격리 입원 동안에 신체적 불편함을 호소하므로 이를 줄여주기 위하여 첫째, 방사성옥소 치료 전 환자들이 저옥소식을 잘 지킬 수 있도록 도움을 주며 둘째, 4일간의 격리입원기간 동안 심리적 어려움과 신체 적불편함을 줄여줌으로써 환자의 만족도를 향상시키는 효과를 기대하고자 본 연구를 하였다. 대상 및 방법: 1. 연구자들의 브레인스토밍을 통해 환자들의 불편함을 파악하였다. 2. 방사성옥소 치료를 위해 입원한 환자 36명에게 입원 기간 동안 느낀 점을 기록하게 하고 이를 조사하였다. 3. 환자 퇴원시에 치료과정에 대한 만족도 설문을 문제점 개선 전 33명, 개선 후 22명에게 조사하였다. 결과: 문제점과 개선안을 도출하였으며 가능한 범위 내에서 개선활동을 실시하였다. 그리고 만족도 설문을 조사하였으며 개선 전 후를 비교하였다. 문제점으로 1) 저옥소식: 맛이 없다, 반찬 가려 먹기가 어렵다. 2) 치료병실 생활: 속이 메스꺼워 음식 섭취가 곤란하다, 병실이 춥다. 3) 호르몬제 투여중지: 전신이 나른하다, 몸이 붓는다가 도출되었으며 이를 해결하기 위한 개선 활동은 1) 입원 전 예약 시에 음식조절(저옥소식)에 대한 설명을 자세히 하였다. 2) 타부서와의 협의-협조사항(치료병실의 청결유지와 쾌적한 병실을 만들기 위해 16층 병동과 협의, 저옥소식 영양상담을 치료 과정중에 넣기 위해 영양과와 협의, 온열매트리스 설치와 보온이불 구입을 위해 시설팀과 협의 등)을 해결하려 노력했다. 3) 전반적인 개선활동(방사성옥소를 차질없이 구입, 치료병실의 치료 전 후 방사능오염 방지, 환자의 심리적 불안감 해소 등)을 하였다. 환자의 만족도 설문에 대한 개선 활동 전 후 비교 결과에서 '치료과정 전체에 대해 힘들었다'는 개선 전 후에 각각 80.6%, 81.8%로 큰 차이가 없었다. 또한 문제점으로 도출된 '저옥소식이 힘들었다'는 개선 전 후에 각각 24.1%, 27.8%로 역시 큰 차이가 없었다. 그러나 '병실생활이 힘들었다'는 개선 전 후에 각각 48.3%, 72.2%로 큰 차이를 보였다. 그리고 '호르몬 투여중지로 인해 힘들었다'는 개선 전 후에 각각 27.6%, 0%로 큰 차이를 보였다. 고찰 및 결론: 환자들의 불편함을 줄여주기 위하여 연구자들의 개선활동이 있었고 그 중에서 입원병실의 생활환경이 특히 향상되었다. 그러나 결과에서 '병실생활이 힘들었다'에 대한 답의 비율은 오히려 더 높아졌다. 이는 '호르몬 투여 중지로 힘들었다'로 답하는 환자의 비율이 상대적으로 줄었기 때문에 높아진 것으로 생각되었다. 방사성옥소 치료로 인해 생길 수밖에 없는 신체적 반응 때문에 대부분의 환자들은 항상 힘들었다고 할 것이다. 만족도 개선 활동으로 환자의 힘든 치료과정을 완전히 해소시켜 줄 수는 없었으나 환자입장에서 생각할 수 있게 된 계기가 되었으며 좀 더 향상된 치료환경을 제공하는 기회가 되었다.

• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.560-564
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• 2016

The objective of this study was to investigate the anti-Bacillus cereus activity of actinonin. Actinonin inhibited the growth of B. cereus in a dose dependent manner. The growth-inhibitory activity of actinonin was evaluated using a broth micro-dilution method, and minimum inhibitory concentration (MIC) and agar disk diffusion tests. B. cereus showed high susceptibility to actinonin in a concentration-dependent manner and MIC was determined to be $0.192{\mu}g/mL$. Additionally, 1 and 2 mM actinonin induced formation of B. cereus inhibition zones. In addition, as compared to B. cereus alone, B. cereus added with $10{\mu}M$ actinonin showed a lower level of cytotoxicity in HeLa cells in vitro. Thus, this study revealed that actinonin could be a potential source of a natural antimicrobial agent or a pharmaceutical component against B. cereus.