• Title/Summary/Keyword: MOF-5

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Preparation of a Composite of Sulfated Zirconia/Metal Organic Framework and its Application in Esterification Reaction

  • Park, Eun Young;Hasan, Zubair;Ahmed, Imteaz;Jhung, Sung Hwa
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1659-1664
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    • 2014
  • A porous metal-organic framework (MOF), MIL-101, was synthesized in the presence of sulfated zirconia (SZ) to produce acidic SZ/MIL-101 composites for the first time. The composites were characterized with XRD, nitrogen adsorption, FT-IR, scanning electron microscope, chemical analysis and so on. The composites (SZ/MIL-101s) were successfully applied in a liquid-phase esterification for a high yield of ester. This catalytic result of SZ/MIL-101, compared with that of pure SZ or MIL-101 (showing a negligible yield of ester), suggests that the SZ in the composite is highly active in the acid catalysis probably because of the well-dispersed active species of SZ. Moreover, the esterification is catalyzed in heterogeneous mode as confirmed by negligible esterification after filtration of the catalyst. Finally, microwaves can be efficiently applied both in the synthesis of the composites and the esterification reaction to accelerate the two processes of synthesis and esterification by about 5 times.

Microwave Synthesis of a Porous Metal-Organic Framework, Nickel(II) Dihydroxyterephthalate and its Catalytic Properties in Oxidation of Cyclohexene

  • Lee, Ji-Sun;Halligudi, Shiva B.;Jang, Nak-Han;Hwang, Dong-Won;Chang, Jong-San;Hwang, Young-Kyu
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1489-1495
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    • 2010
  • A porous coordination solid of nickel(II) dihydroxyterephthalate has been synthesized by the microwave-assisted (MW) method. The synthesized nickel(II) dihyroxylterephthalate was designated by the general formula of [$Ni_2$(dhtp) $(H_2O)_2]{\cdot}8H_2O$ (where, dhtp = 2,5-dihydroxyterephthalate, denoted by Ni-DHTP). The effect of microwave-irradiation temperature and time of irradiation on the porosity and morphological changes in the solids have also been investigated. The catalytic performance of Ni-DHTP synthesized by MW method has been studied in the oxidation of cyclohexene with aqueous $H_2O_2$, which gave cyclohexene oxide as the primary product and 2-cyclohexene-1-ol as a major product.

CO2 Capture & Separation in Microporous Materials: A Comparison Between Porous Carbon and Flexible MOFs (다공성 물질을 이용한 CO2 포집 및 분리: 다공성 탄소와 유연한 MOF 비교 연구)

  • Jung, Minji;Park, Seoha;Oh, Hyunchul;Park, Kwi-il
    • Korean Journal of Materials Research
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    • v.28 no.7
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    • pp.417-422
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    • 2018
  • The stereotype of flexible MOFs(Amino-MIL-53) and carbonized porous carbon prepared from renewable resources is successfully synthesized for $CO_2$ reduction application. The textural properties of these microporous materials are investigated, and their $CO_2$ storage capacity and separation performance are evaluated. Owing to the combined effects of $CO_2-Amino$ interaction and its flexibility, a $CO_2$ uptake of $2.5mmol\;g^{-1}$ is observed in Amino-MIL-53 at 20 bar 298 K. In contrast, $CH_4$ uptake in Amino-MIL-53 is very low up to 20 bar, implying potential sorbent for $CO_2/CH_4$ separation. Carbonized samples contain a small quantity of metal residues(K, Ca, Mg, S), resulting in naturally doped porous carbon. Due to the trace metal, even higher $CO_2$ uptake of $4.7mmol\;g^{-1}$ is also observed at 20 bar 298 K. Furthermore, the $CH_4$ storage capacity is $2.9mmol\;g^{-1}$ at 298 K and 20 bar. To evaluate the $CO_2$ separation performance, the selectivity based on ideal adsorption solution theory for $CO_2/CH_4$ binary mixtures on the presented porous materials is investigated.

A Study on the Outages Due to Voltage Expanding in Closing High Voltage Capacitor (고압 커패시터 투입시 전압확대에 따른 사고 사례 연구)

  • Cho, Nam-Hoon;Jung, Jum-Soo;Park, Yong-Woo;Ha, Bok-Nam;Lee, Hyung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.9
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    • pp.94-102
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    • 2008
  • Capacitor switching is essential for the economic operation and proper voltage control of KOREA electric utility distribution system. Voltage transients produced by capacitor switching (around 2.0 per unit at substation and 2.5 or less per unit at customer site, and lasting less then 1[ms]) do not have the magnitude or duration to interfere with the operation of computers, but they do disrupt the operation of adjustable speed drivers. The result of our research, ASD manufacturers should learn from the computer industry and design products that will operate satisfactory In the electrical envelopment in which they will be placed. In this case history, the inductors on the input to ADSs in order to prevent nuisance tripping from capacitor switching(and other causes within the apartment) proved to be an effective, low-cost solution.

Assessment of Bacteriological Safety of the Seawater and Ark shell (Scapharca subcrenata) in Yeoja Bay, Korea (전남 여자만 해수 및 새꼬막(Scapharca subcrenata)의 세균학적 위생 평가)

  • SHIN, SoonBum;OH, Eun Gyoung;JEONG, Sang Hyeon;LEE, Hee Jung;KIM, Yeon Kye;LEE, Tae Seek
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.5
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    • pp.1435-1443
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    • 2016
  • This study evaluated the sanitary state of seawater and shellfish in Yeoja bay from January 2014 to June 2016. The sampling stations for sanitary survey in Yeoja Bay was composed of 50 stations for seawater and 4 stations for ark shell and the samples have been collected monthly at a stated date. The total and fecal coliforms in seawater and Escherichia coli (E. coli) in shellfish were investigated as sanitary indicator bacteria, respectively. The geometric mean and the estimated 90th percentile ranges of total and fecal coliforms for seawater were <1.8-3.9, <1.8-2.6 and <1.8-29.7, <1.8-9.3 MPN/100 mL, respectively. The range of E. coli levels for ark shell were <20~330 MPN/100 g. The sanitary state in Yeoja bay was evaluated clean area according Korea criteria and conditionally approved area according US criteria and Class B area according EU criteria.

A Study on Inspection Status of Port State Control and Improvement Measures in Korea (우리나라 항만국통제 점검 실태와 문제점 개선에 관한 연구)

  • Kim, Sun-Tai;Gang, Sang-Geun;Jeong, Jae-Yong;Kim, Deug-Bong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.6
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    • pp.671-676
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    • 2014
  • Based on the data of PSC information management system of MOF(Ministry of oceans and fisheries) and APCIS(Asia-Pacific Computerized Information System) of Tokyo-MOU information system, the result of the evaluation on the reality of PSC was done, and base on 2009, it showed a trend of decrease in every DFR(Deficiency Rate) and DTR(Detention Rate). But for vessels built for more than 30 years, flags of convenience vessels, RO-RO ferry and general cargo vessel, small size vessels with gross tonnage less than 1,000 ton showed a high DFR and DTR. Each harbours is classified by the total harbours' average DFR which was 82.5 % and the average DTR was 5.1 %, excluding the Jeju harbour, showing a hugh deviation for classification of each harbour. Classification of each harbour has to be inspected by PSC and it showed a great unbalance of the number of vessels for each territory for inspection. the biggest problem with our country's PSC, where it was pointed out by the PSCO was lack of workers and independent inspection by just one worker. To strength the substantiality of the inspection of our country is to have concentrated inspection on the high risk cautious vessels, forming a human network each classified by four different sectors of the area, recalculating the amount of assignment of inspection classified by each harbour and securing workforce the PSCO improvements are necessary.

Changes of Surface Temperature and Electromyography Activities by Local Heat and Cold (온열과 냉의 국소적용에 의한 체표면 온도와 근전도 활동의 변화)

  • Choi, Seok-Ju;Lim, Sang-Wan;Kim, Su-Hyon;Mun, Dal-Ju
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.5 no.2
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    • pp.61-72
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    • 2007
  • INTRODUCTION: Local heat and cold application has been frequently used as means of muscle relaxation and blood circulation or reinforcing muscle strength, relaxing muscle tension in clinical situation. In particular, it has been known that long-term heat and cold application for relaxing muscle tension inhibits muscle spasticity or tension. But, it has been rarely reported that what influences of heat and cold application on activation of muscle action potential. Therefore, this study aims to analyze surface temperature and electromyography activities according to the heat and cold application. METHODE: Subjects of this research were 10 normal men and women (5 men, 5 women). Hot pack and cold pack was applied to vastus medialis muscle of thigh and rectus femoris muscle for 20 min. Surface temperature of vastus medialis muscle and rectus femoris muscle was measured, knee joint of subjects was in $45^{\circ}$ flexion, sitting on a chair, maximal isometric contraction was induced, surface electromyography (sEMG) signals were collected and root mean square (RMS) and median frequency (MOF) were analyzed. All measurements were conducted before and immediately after experiment, 10 min., 20 min. and 30 min. after experiment. Data were analyzed with SPSS 12.0 program, comparison of changes in superficial temperature and sEMG signals through repeated measurement was conducted with repeated measures ANOVA and significance level $\alpha$ was 0.05. RESULTS: Changes of surface temperature of vastus medialis muscle according to cold application were radically decreased immediately after application, but it was recovered after 30 min. of application and it showed significant difference (F4. 36=72.216, P<0.001). Surface temperature of rectus femoris also showed radical decrease immediately after application, but it was recovered after 30 min. of application and showed significant difference (F4. 36=88.930, P<0.001). Changes of surface temperature of vastus medialis muscle according to heat application were radically increased immediately after application, but it was recovered after 30 min. of application and it showed significant difference (F4. 36=27.267, P<0.001). Surface temperature of rectus femoris also showed radical decrease immediately after application, but it was recovered after 30 min. of application and showed significant difference (F4. 36=19.774, P<0.001). Changes of sEMG by heat and cold application were no statistical difference. Surface temperature of skeletal muscle after heat and cold application showed significant change for 30 min., but it was found that increase or decrease of surface temperature had not great influence on sEMG activities.

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Impacts of Local Meteorology caused by Tidal Change in the West Sea on Ozone Distributions in the Seoul Metropolitan Area (서해 조석현상에 따른 국지기상 변화가 수도권 오존농도에 미치는 영향)

  • Kim, Sung Min;Kim, Yoo-Keun;An, Hye Yeon;Kang, Yoon-Hee;Jeong, Ju-Hee
    • Journal of Environmental Science International
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    • v.28 no.3
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    • pp.341-356
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    • 2019
  • In this study, the impacts of local meteorology caused by tidal changes in the West Sea on ozone distributions in the Seoul Metropolitan Area (SMA) were analyzed using a meteorological model (WRF) and an air quality (CMAQ) model. This study was carried out during the day (1200-1800 LST) between August 3 and 9, 2016. The total area of tidal flats along with the tidal changes was calculated to be approximately $912km^2$, based on data provided by the Environmental Geographic Information Service (EGIS) and the Ministry of Oceans and Fisheries (MOF). Modeling was carried out based on three experiments, and the land cover of the tidal flats for each experiment was designed using the coastal wetlands, water bodies (i.e., high tide), and the barren or sparsely vegetated areas (i.e., low tide). The land cover parameters of the coastal wetlands used in this study were improved in the herbaceous wetland of the WRF using updated albedo, roughness length, and soil heat capacity. The results showed that the land cover variation during high tide caused a decrease in temperature (maximum $4.5^{\circ}C$) and planetary boundary layer (PBL) height (maximum 1200 m), and an increase in humidity (maximum 25%) and wind speed (maximum $1.5ms^{-1}$). These meteorological changes increased the ozone concentration (about 5.0 ppb) in the coastal areas including the tidal flats. The increase in the ozone concentration during high tide may be caused by a weak diffusion to the upper layer due to a decrease in the PBL height. The changes in the meteorological variables and ozone concentration during low tide were lesser than those occurring during high tide. This study suggests that the meteorological variations caused by tidal changes have a meaningful effect on the ozone concentration in the SMA.

New Governmental National Agenda and New Executive Bodies' R&D Strategic Goals on Geoscience and Mineral Resources (신정부 국정과제 및 지질자원 분야 R&D 정책 방향 분석)

  • Ahn, Eun-Young;Lee, Jae-Wook;Park, Jung-Kyu
    • Economic and Environmental Geology
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    • v.46 no.5
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    • pp.469-476
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    • 2013
  • With the advent of a new Korean government, a new national agenda (140 items) was reported. Additionally, Work Plans of the executive bodies were also released, including the Ministry of Science, ICT and Future Planning (MSIP); the Ministry of Trade, Industry and Energy (MOTIE); the Ministry of Oceans and Fisheries (MOF); and the Ministry of Environment (MOE); the Ministry of Land, Infrastructure, and Transport (MOLIT). For government-supported research institutes, it will be important to watch and analyze the changes in the government's primary policies and strategic goals. In this paper, we analyzed new governmental research and development (R&D) policy with respect to geoscience and mineral resources technology. The results indicated that the executive bodies emphasized, for the job creating 'creative economy' and the 'safety and integration society', the establishment of the creative economy; science and technology development based on creativity and innovation; creation of new growth engines by fusion and diffusion; construction of stable energy systems; promotion of environmental industry; and creating satisfactory land services. In the area of geoscience and mineral resources technology, it is time to search for a new, creative, and interagency fusion R&D contents to meet the needs of the public and boost its national competitiveness.

A Study on the Improvement Measures for the Safe Maneuvering of Passenger Ships in Port Area through Analysis of Marine Accidents (여객선 해양사고 분석을 통한 안전한 항내조선 개선방안에 관한연구)

  • Chong, Dae-Yul
    • Journal of Navigation and Port Research
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    • v.46 no.1
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    • pp.18-25
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    • 2022
  • MOF strengthen the law and institutions for safety management after the capsize accident of passenger ship "Sewol" on April 16, 2014. Nevertheless, about 13 cases of marine accidents such as collisions, contact, and stranding have occurred in coastal passenger ships over the past 5 years. Particularly, according to the judgment of KMST, most of the main causes of passenger ship accidents occurred within harbor areas because of the master's improper ship-handling or inattention. And so, this study analyzed four cases of marine accidents on passenger ships that occurred in the port areas and examined the environmental, institutional, material, and human factors that contributed to the master's improper ship-handling and behavior, and the results are as follows. First, as an environmental factor, the size of the turning basin was not enough. Second, as an institutional factor, the VTS control was not properly supported, the master lacked sufficient training for safe ship-handling in the port area and up-to-date charts were not provided. Third, as a material factor, the digital type speed log capable of the ship's speed in real-time was not installed on the ship's wing bridge. Lastly, as a human factor, the master could not take proper bridge resources and the passage plan was not proper. Therefore, it is suggested in this paper that the size of the turning basin should be adjusted to meet the prescribed standards, the master of passenger ships should receive the ship-handling simulation training among other safety training to ensure safe ship-handling of the master in the port area as improvement measures.