Liquid metal extraction (LME), a pyrometallurgical recycling method, is popular owing to its negligible environmental impact. LME mainly targets rare-earth permanent magnets having several rare-earth elements. Mg is used as a solvent metal for LME because of its selective and eminent reactivity with rare-earth elements in magnets. Several studies concerning the formation of Dy-Fe intermetallic compounds and their effects on LME using Mg exist. However, methods for reducing these compounds are unavailable. Fe reacts more strongly with B than with Dy; B addition can be a reducing method for Dy-Fe intermetallic compounds owing to the formation of Fe2B, which takes Fe from Dy-Fe intermetallic compounds. The FeB alloy is an adequate additive for the decomposition of Fe2B. To accomplish the former process, Mg must convey B to a permanent magnet during the decomposition of the FeB alloy. Here, the effect of Mg on the transfer of B from FeB to permanent magnet is observed through microstructural and phase analyses. Through microstructural and phase analysis, it is confirmed that FeB is converted to Fe2B upon B transfer, owing to Mg. Finally, the transfer effect of Mg is confirmed, and the possibility of reducing Dy-Fe intermetallic compounds during LME is suggested.

Rare earth magnets with excellent magnetic properties are indispensable in the electric device, wind turbine, and e-mobility industries. The demand for the development of eco-friendly recycling techniques has increased to realize sustainable green technology, and the supply of rare earth resources, which are critical for the production of permanent magnets, are limited. Liquid metal extraction (LME), which is a type of pyrometallurgical recycling, is known to selectively extract the metal forms of rare earth elements. Although several studies have been carried out on the formation of intermetallic compounds and oxides, the effect of oxide formation on the extraction efficiency in the LME process remains unknown. In this study, microstructural and phase analyses are conducted to confirm the oxidation behavior of magnets pulverized by a jaw crusher. The LME process is performed with pulverized scrap, and extraction percentages are calculated to confirm the effect of the oxide phases on the extraction of Dy during the reaction. During the LME p rocess, Nd i s completely e xtracted a fter 6 h, w hile D y remains as D y2Fe17 and Dy-oxide. Because the decomposition rate of Dy2Fe17 is faster than the reduction rate of Dy-oxide, the importance of controlling Dy-oxide on Dy extraction is confirmed.

The study aimed to determine effects of light emitting diode (LED) and the ultraviolet radiation (UVA) light of plant factory on plant growth and ascorbic acid content of spinach (Spinacia oleracea cv. Shusiro). Plants were grown in a NFT (Nutrient Film Technique) system for 28 days after transplanting with fluorescent light (FL, control), LEDs and UVA (Blue+UVA (BUV), Red and Blue (R:B(2:1)) + UVA (RBUV), Red+UVA (RUV), White LED (W), Red and Blue (R:B(2:1)), Blue (B), Red (R)) under the same light intensity (130 μmol·m-2·s-1) and photoperiod (16/8h = day/night). All the light sources containing the R (R, RB, RUV, and RBUV) showed leaf epinasty symptom at 21 days after transplanting (DAT). Under the RUV treatment, the lengths of leaf and leaf petiole were significantly reduced and the leaf width was increased, lowering the leaf shape index, compared to the R treatment. Under the BUV, however, the lengths of leaf and leaf petiole were increased significantly, and the leaf number was increased compared to B. Under the RBUV treatment, the leaf length was significantly shorter than other treatments, while no significant difference between the RBUV and RB for the fresh and dry weights and leaf area. Dry weights at 28 days after transplanting were significantly higher in the R, RUV and BUV treatments than those in the W and FL. The leaf area was significantly higher under the BUV treatment. The ascorbic acid content of the 28 day-old spinach under the B was significantly higher, followed by the BUV, and significantly lower in FL and R. All the integrated data suggest that the BUV light seems to be the most suitable for growth and quality of hydroponically grown spinach in a plant factory.

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from 0.002 μg/L to 0.013 μg/L and in 0.001 μg/L to 0.008 μg/L, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from 0.002 μg/L to 0.630 μg/L) and NDEA (from 0.005 μg/L to 0.100 μg/L) observed in the this study were low.

본 실험은 LED 광원이 시금치 품종 별 생육, 잎 형태 변화 및 세포 길이에 대한 영향을 구명하고자 수행하였다. 최아된 시금치(Spinacia oleracea.) 품종 ‘월드스타’와 ‘수시로’를 버미큘라이트에 육묘한 후 NFT 시스템에 정식 한 뒤 LED 적색광(R), 청색광(B), 혼합광(적색:청색=2:1)(RB) 및 백색광(W)에서 130μmol·m-2·s-1 PPFD 광도로 25일간 재배하였다. 정식 후 일주일 간격으로 25일 동안 엽장, 엽폭, 엽병, 엽수, 광합성률을 측정하였고, 상편생장지수(leaf epinasty index, LEI)는 잎이 최대로 전개된 후에 측정하였다. 상편생장이 발생된 잎 가운데와 가장자리를 자른 조직의 세포길이, 폭 및 세포면적은 400배율 광학현미경을 이용하여 측정하였다. 정식 후 25일째에는 엽면적, 뿌리길이, 지상부 및 지하부의 생체중, 건물중을 조사하였다. 지상부 생체중과 건물중, 엽수, 엽면적 모두 월드스타 품종이 수시로 품종에 비해 유의적으로 높았다. 건물중은 월드스타 품종의 경우 혼합광(RB)와 적색광(R) 두 처리구에서 청색광(B)와 흰색광(W) 두 처리보다 약 35% 유의적으로 높았다. 수시로 품종의 경우 혼합광(RB) 처리구에서 지상부 건물중이 가장 높아 건물중이 가장 낮았던 흰색광(W) 처리구에 비해 40% 높은 건물중 결과를 보였다. 두 품종 모두 혼합광(RB)와 적색광(R) 두 처리구에서만 정식 21일 이후 잎 상편생장(leaf epinasty)이 나타났고 적색광(R) 처리구에서 혼합광(RB) 처리구 보다 유의적으로 높아 잎 상편 생장은 적색광(R)과 관련이 있는 것을 알 수 있었다. 잎 가운데와 가장자리 부위 세포크기를 현미경으로 관찰한 결과 두 품종 모두 상편생장이 나타난 적색광(R) 처리구의 잎 가장자리 세포밀도가 잎 가운데 보다 낮은 것으로 나타나 앞서 보고된 연구결과들에서 제시한 상편생장과 잎 가운데와 가장자리 부위의 세포크기 차이 연관성을 뒷받침하고 있다. 또한 청색광(B)이 적색광(B)에서 발생되는 상편생장을 완화시켜주는 역할을 하는 것으로 보여 앞으로 두 광원의 적절한 혼합비율 규명이 필요한 것으로 판단된다. 또한, 엽형 변화가 심했던 수시로 품종보다는 월드스타 품종이 LED 광원을 이용한 식물공장 재배에 더 적합한 것으로 판단된다.

The chemical structures of perfluorinated compounds(PFCs) have unique properties such as thermal and chemical stability that make them useful components in a wide variety of consumer and industrial products. Two of these PFCs, perfluorooctane sulfonate(PFOS) and perfluorooctanoic acid(PFOA), have received attention and were the most commonly detected. In this study it was analyzed the concentrations of 8 PFCs in samples were collected from drinking water treatment plants for 5 years(2012-2016). PFOS and PFOA were also high concentration and frequency. The mean concentrations of PFOA and PFOS were detected 0.0026-0.0069 μg/L and 0.0009-0.0024 μg/L in samples from drinking water treatment plants. These were relatively lower or similar compared to PFOS concentrations in Osaka(Japan). In general, these levels are below health-based values set by international authoritative bodies for drinking water. These results will be serve as the first monitoring data for PFCs in drinking water and be useful for characterizing the concentration distribution and management of PFCs in future studies.

PURPOSES :This study was initiated to estimate the utilities of usage attributes of BRT and Bimodal Trams using a conjoint analysis method in order to identify the important features pertaining to the use of BRT and Bimodal Trams.METHODS :For this purpose, important attributes and those level in the use of BRT and Bimodal Trams in the city of Sejong were identified. Next, a profile questionnaire pertaining to BRT and Bimodal Trams was designed for the conjoint analysis, and a survey was conducted in the city of Sejong. Using SPSS software, conjoint analysis was performed to identify the important attributes vis｀-a-vis the use of BRT and Bimodal Trams in the city of Sejong. Finally, the utilities for individual attributes were calculated based on the models estimated by the conjoint analysis.RESULTS :The results of the conjoint analysis were used to identify the important attributes. With regard to the usage of BRT, users indicated that fare was the most important attribute with the highest utility. In the case of Bimodal Trams, the users indicated that the number of seats and internal environment were the most important attributes with the highest utilities.CONCLUSIONS :Based on the results of the conjoint analysis, the important attributes pertaining to the use of BRT and Bimodal Trams in the city of Sejong were identified. Our study indicates that BRT in the city of Sejong needs to be upgraded to improve the utilities of the important attributes. Currently, Bimodal Trams has not been introduced completely in the city of Sejong. However, in the future, when the introduction of Bimodal Trams is completed, the important attributes should be emphasized in order to improve the quality of its service.

급격한 산업화 및 인구증가로 물부족 문제가 가속화됨에 따라 최근 수처리 공정은 방류수 수질기준을 준수하여 방류하는 단순한 수준을 넘어서 보다 엄격한 수질을 만족시켜야하는 방향으로 발전하고 있는 추세이다. 이러한 노력의 일환으로 많은 하⋅폐수 처리장에서 생물학적 처리와 멤브레 인이 결합된 MBR 공정을 적용하고 있으나, 적용 현장별 특징을 충분히 반영하지 못한 설계로 MBR 공정의 우수한 처리성능을 제대로 활용하지 못하고 있는 실정이다. 이에, 본 연구에서는 산업단지 내에 설치되는 폐수처리시설의 입지여건과 특성을 반영하여 저유량 및 수질의 불균질화 문제를 해결하기 위한 설계사례 등 을 제시하고자 하였다.

이 연구에서는 풍력-태양광 하이브리드 가로등 구조물에 대한 동적 응답을 계측하여, 서로 다른 터빈을 적용하였을 때의 진동 특성 및 공진현상을 비교하였다. 2엽 및 3엽 풍력터빈을 적용하였으며, 하이브리드 가로등이 가지고 있는 진동 특성은 가동 중인 조건에서의 동특성과 가진력을 비교하여 분석하였다. 최근 제안된 방법을 통해 가속도 계측자료를 이용하여 변위 응답을 추정하였고, 2엽 풍력터빈을 적용한 경우 동적 변위 응답의 진폭은 공진 하의 조건에서 4~6cm 범위에 있고, 3엽 풍력터빈을 적용한 경우에는 공진이 발생하지 않아 변위는 2mm 이내로 제한됨을 알 수 있었다.

Plant breeding is a multidisciplinary science of changing the genetic makeup of plants in order to generate desired traits or characteristics, and thus it can be accomplished through many different techniques ranging from simply selecting plants with desirable traits for propagation to more complex molecular techniques. Both conventional and genetically modified (GM) plant breeding alter or modify the genes of a plant so that a better variety is developed. Breeding using GM tools is achieved for the same reasons as conventional breeding. One prominent distinction is that instead of randomly mixing genes in conventional breeding, which occurs as a result of a sexual cross, a specific gene is directly transferred or selectively inactivated in the new plant variety through GM plant breeding. Site-specific mutagenesis and selection of gene knockout mutants are readily carried out in model plant species, such as Arabidopsis. However, targeted mutation of a specific gene is technically impractical, if not impossible, in most cases. As an alternative approach, RNA interference (RNAi), which is mediated by small interfering RNA (siRNA) and microRNA (miRNA), is routinely employed for targeted silencing of genes in academic and biotechnological studies. Recently, engineered nuclease-based genome editing tools, such as zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), have been developed to induce site-specific genome modifications in both animals and plants. ZFNs are chimeric DNA restriction enzymes that consist of the nuclease domain of the Fok1 restriction enzyme, which triggers double strand breaks in genomic DNAs, and a custom-designed ZF DNA-binding domain, which guides the ZFNs to specific sequences within genomic DNAs. The double-strand breaks are rejoined by cellular DNA repair machinery, resulting in targeted mutagenesis or targeted gene replacement. In this work, we employed the ZFN tool to specifically inactivate two flowering genes, such as FCA and GI that also mediate high temperature responses and clock output signaling, respectively, in a bioenergy grass crop, Brachypodium distachyon. We designed extensive sets of ZF recognition sequences that recognize target sequences within the FCA and GI genes. The potential ZFN cassettes were transformed into Brachypodium ecotype Bd21-3. The transformants will be screened to identify those carrying targeted gene mutations. We will also discuss the extension of the ZFN tool to other plant species, including crops.