• Title/Summary/Keyword: 효율적

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Heterogeneous Oxidation of Liquid-phase TCE over $CoO_x/TiO_2$ Catalysts (액상 TCE 제거반응을 위한 $CoO_x/TiO_2$ 촉매)

  • Kim, Moon-Hyeon;Choo, Kwang-Ho
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.3
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    • pp.253-261
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    • 2005
  • Catalytic wet oxidation of ppm levels of trichloroethylene (TCE) in water has been conducted using $TiO_2$-supported cobalt oxides at a given temperature and weight hourly space velocity. 5% $CoO_x/TiO_2$ might be the most promising catalyst for the wet oxidation at $36^{\circ}C$ although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Characterization of the $CoO_x$ catalyst by acquiring XPS spectra of both fresh and used Co surfaces gave different surface spectral features of each $CoO_x$. Co $2p_{3/2}$ binding energy of Co species exposed predominantly onto the outermost surface of the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $Co_2TiO_4$ and $CoTiO_3$. The spent catalyst possessed a 780.3 eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD measurements indicated that the phase structure of Co species in 5% $CoO_x/TiO_2$ catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.

The Effect of addition of CuO to Fe2O3/ZrO2 Oxygen Carrier for Hydrogen Production by Chemical Looping (매체 순환식 수소제조공정에 적합한 Fe2O3/ZrO2 산소전달입자에 구리 산화물 첨가가 미치는 영향에 관한 연구)

  • Lee, Jun Kyu;Kim, Cho Gyun;Bae, Ki Kwang;Park, Chu Sik;Kang, Kyoung Soo;Jeong, Seong Uk;Kim, Young Ho;Joo, Jong Hoon;Cho, Won Chul
    • Korean Chemical Engineering Research
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    • v.54 no.3
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    • pp.394-403
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    • 2016
  • $H_2$ production by chemical looping is an efficient method to convert hydrocarbon fuel into hydrogen with the simultaneous capture of concentrated $CO_2$. This process involves the use of an iron based oxygen carrier that transfers pure oxygen from oxidizing gases to fuels by alternating reduction and oxidation (redox) reactions. The enhanced reactivities of copper oxide doped iron-based oxygen carrier were reported, however, the fundamental understandings on the interaction between $Fe_2O_3$ and CuO are still lacking. In this study, we studied the effect of dopant of CuO to $Fe_2O_3/ZrO_2$ particle on the morphological changes and the associated reactivity using various methods such as SEM/EDX, XRD, BET, TPR, XPS, and TGA. It was found that copper oxide acted as a chemical promoter that change chemical environment in the iron based oxygen carrier as well as a structural promoter which inhibit the agglomeration. The enhanced reduction reactivity was mainly ascribed to the increase in concentration of $Fe^{2+}$ on the surface, resulting in formation of charge imbalance and oxygen vacancies. The CuO doped $Fe_2O_3/ZrO_2$ particle also showed the improved reactivity in the steam oxidation compared to $Fe_2O_3/ZrO_2$ particle probably due to acting as a structural promoter inhibiting the agglomeration of iron species.

A Quick-and-dirty Method for Detection of Ground Moving Targets in Single-Channel SAR Single-Look Complex (SLC) Images by Differentiation (미분을 이용한 단일채널 SAR SLC 영상 내 지상 이동물체의 탐지방법)

  • Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.30 no.2
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    • pp.185-205
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    • 2014
  • SAR ground moving target indicator (GMTI) has long been an important issue for SAR advanced applications. As spatial resolution of space-borne SAR system has been significantly improved recently, the GMTI becomes a very useful tool. Various GMTI techniques have been developed particularly using multi-channel SAR systems. It is, however, still problematic to detect ground moving targets within single channel SAR images while it is not practical to access high resolution multi-channel space-borne SAR systems. Once a ground moving target is detected, it is possible to retrieve twodimensional velocities of the target from single channel space-borne SAR with an accuracy of about 5 % if moving faster than 3 m/s. This paper presents a quick-and-dirty method for detecting ground moving targets from single channel SAR single-look complex (SLC) images by differentiation. Since the signal powers of derivatives present Doppler centroid and rate, it is very efficient and effective for detection of non-stationary targets. The derivatives correlate well with velocities retrieved by a precise method with a correlation coefficient $R^2$ of 0.62, which is well enough to detect the ground moving targets. While the approach is theoretically straightforward, it is necessary to remove the effects of residual Doppler rate before finalizing the ground moving target candidates. The confidence level of results largely depends on the efficiency and effectiveness of the residual Doppler rate removal method. Application results using TerraSAR-X and truck-mounted corner reflectors validated the efficiency of the method. While the derivatives of moving targets remain easily detectable, the signal energy of stationary corner reflectors was suppressed by about 18.5 dB. It results in an easy detection of ground targets moving faster than 8.8 km/h. The proposed method is applicable to any high resolution single channel SAR systems including KOMPSAT-5.

Risk Management and Strategies in Airport Security Check (공항 보안검색에 있어서의 위험관리와 대응과제)

  • Kim, Jae-Woon
    • Korean Security Journal
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    • no.34
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    • pp.89-113
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    • 2013
  • Travel by airplane using airport in globalized modern society is familiar to our life but such airport can be a target of terrorists who would threaten our safety. However, aviation terrorism which is represented by 9.11 terror gives horror beyond our imagination to modern people. Since the first airplane hijacking in Peru in 1931 happened, security organization in each nation has taken various prevention measures to block aviation terrorism. The most realistic measures to prevent aviation terrorism would be security check activity to control approach of terrorist that passengers on airplane and cargos are checked to find out dangerous article like explosive etc. But security check activity in Korea shifted to security check activity focused on private security for efficiency of airport operation differently from security check activity in advanced countries where public interests is strengthened according to risk of terror after 9.11 system. That is, since Incheon airport opened in March 2001, security check system focused on the police was changed. Now Incheon international airport Corporation instructs and supervises security check job and private security personnel are in charge of actual security check activity. But this check system has limitation in blocking terror activity by terrorists which is systematized and intelligent as time passes due to deteriorated job satisfaction of private security personnel and confusing supervising system. Accordingly, it is suggested to introduce risk management skill which is one of management strategy of private corporation for security check activity to prevent terror activity. With this skill, risk factors of aviation terror are identified and analyzed regularly, and each process such as setting of priority, activity to reduce risk, and assessment of security is carried out. And it would be necessary to do efforts, for example, to properly change level of security check according to threat of terror such as to place policeman at airport security in case threat of terror is severe. On the other hand, it is necessary to establish national police organization for good communication of security check activity in field and supervising function, which can encourage systematization and specialization of aviation security job.

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A Study of Improvement for the Prediction of Groundwater Pollution in Rural Area: Application in Keumsan, Korea (농촌지역 지하수의 오염 예측 방법 개선방안 연구: 충남 금산 지역에의 적용)

  • Cheong, Beom-Keun;Chae, Gi-Tak;Koh, Dong-Chan;Ko, Kyung-Seok;Koo, Min-Ho
    • Journal of Soil and Groundwater Environment
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    • v.13 no.4
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    • pp.40-53
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    • 2008
  • Groundwater pollution prediction methods have been developed to plan the sustainable groundwater usage and protection from potential pollution in many countries. DRASTIC established by US EPA is the most widely used groundwater vulnerability mapping method. However, the DRASTIC showed limitation in predicting the groundwater contamination because the DRASTIC method is designed to embrace only hydrogeologic factors. Therefore, in this study, three different methods were applied to improve a groundwater pollution prediction method: US EPA DRASTIC, Modified-DRASTIC suggested by Panagopoulos et al. (2006), and LSDG (Land use, Soil drainage, Depth to water, Geology) proposed by Rupert (1999). The Modified-DRASTIC is the modified version of the DRASTIC in terms of the rating scales and the weighting coefficients. The rating scales of each factor were calculated by the statistical comparison of nitrate concentrations in each class using the Wilcoxon rank-sum test; while the weighting coefficients were modified by the statistical correlation of each parameter to nitrate concentrations using the Spearman's rho test. The LSDG is a simple rating method using four factors such as Land use, Soil drainage, Depth to water, and Geology. Classes in each factor are compared by the Wilcoxon rank-sum test which gives a different rating to each class if the nitrate concentration in the class is significantly different. A database of nitrate concentrations in groundwaters from 149 wells was built in Keumsan area. Application of three different methods for assessing the groundwater pollution potential resulted that the prediction which was represented by a correlation (r) between each index and nitrate was improved from the EPA DRASTIC (r = 0.058) to the modified rating (r = 0.245), to the modified rating and weights (r = 0.400), and to the LSDG (r = 0.415), respectively. The LSDG seemed appropriate to predict the groundwater pollution in that it contained land use as a factor of the groundwater pollution sources and the rating of each class was defined by a real pollution nitrate concentration.

Estimation of $CO_2$ saturation from time-lapse $CO_2$ well logging in an onshore aquifer, Nagaoka, Japan (일본 Nagaoka 육상 대수층에서 시간차 $CO_2$ 물리검층으로부터 $CO_2$ 포화도의 추정)

  • Xue, Ziqiu;Tanase, Daiji;Watanabe, Jiro
    • Geophysics and Geophysical Exploration
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    • v.9 no.1
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    • pp.19-29
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    • 2006
  • The first Japanese pilot-scale $CO_2$ sequestration project has been undertaken in an onshore saline aquifer, near Nagaoka in Niigata prefecture, and time-lapse well logs were carried out in observation wells to detect the arrival of injected $CO_2$ and to evaluate $CO_2$ saturation in the reservoir. $CO_2$ was injected into a thin permeable zone at the depth of 1110m at a rate of 20-40 tonnes per day. The total amount of injected $CO_2$ was 10400 tonnes, during the injection period from July 2003 to January 2005. The pilot-scale demonstration allowed an improved understanding of the $CO_2$ movement in a porous sandstone reservoir, by conducting time-lapse geophysical well logs at three observation wells. Comparison between neutron well logging before and after the insertion of fibreglass casing in observation well OB-2 showed good agreement within the target formation, and the higher concentration of shale volume in the reservoir results in a bigger difference between the two well logging results. $CO_2$ breakthrough was identified by induction, sonic, and neutron logs. By sonic logging, we confirmed P-wave velocity reduction that agreed fairly well with a laboratory measurement on drilled core samples from the Nagaoka site. We successfully matched the history changes of sonic P-wave velocity and estimated $CO_2$ saturation a(ter breakthrough in two observation wells out of three. The sonic-velocity history matching result suggested that the sweep efficiency was about 40%. Small effects of $CO_2$ saturation on resistivity resulted in small changes in induction logs when the reservoir was partially saturated. We also found that $CO_2$ saturation in the $CO_2$-bearing zone responded to suspension of $CO_2$ injection.

Statistical Optimization of Solid Growth-medium for Rapid and Large Screening of Polysaccharides High-yielding Mycelial Cells of Inonotus obliquus (단백다당체 고생산성의 Inonotus obliquus 균주의 신속 개량을 위한 고체 성장배지의 통계적 최적화)

  • Hong, Hyung-Pyo;Jeong, Yong-Seob;Chun, Gie-Taek
    • KSBB Journal
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    • v.25 no.2
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    • pp.142-154
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    • 2010
  • The protein-bound innerpolysaccharides (IPS) produced by suspended mycelial cultures of Inonotus obliquus have promising potentials as an effective antidiabetic as well as an immunostimulating agents. To enhance IPS production, intensive strain improvement process should be carried out using large amount of UV-mutated protoplasts. During the whole strain-screening process, the stage of solid growth-culture was found to be the most time-requiring step, thus preventing rapid screening of high-yielding producers. In order to reduce the cell growth period in the solid growth-stage, therefore, solid growth-medium was optimized using the statistical methods such as (i) Plackett-Burman and fractional factorial designs (FFD) for selecting positive medium components, and (ii) steepest ascent (SAM) and response surface (RSM) methods for determining optimum concentrations of the selected components. By adopting the medium composition recommended by the SAM experiment, significantly higher growth rate was obtained in the solid growth-cultures, as represented by about 41% larger diameter of the cell growth circle and higher mycelial density. Sequential optimization process performed using the RSM experiments finally recommended the medium composition as follows: glucose 25.61g/L, brown rice 12.53 g/L, soytone peptone 12.53 g/L, $MgSO_4$ 5.53 g/L, and agar 20 g/L. It should be noted that this composition was almost similar to the medium combinations determined by the SAM experiment, demonstrating that the SAM was very helpful in finding out the final optimum concentrations. Through the use of this optimized medium, the period for the solid growth-culture could be successfully reduced to about 8 days from the previous 15~20 days, thus enabling large and mass screening of high producers in a relatively short period.

Anti-atherogenic Effect of Isoflavone through Hypolipidemic, Anti-oxidative and Anti-inflammatory Actions in C57BL/6 Mice (C57BL/6 Mice에서 이소플라본의 지질강하, 항산화, 항염증효과를 통한 항동맥경화 효과)

  • Cho, Hye-Yeon;Yang, Jeong-Lye;Noh, Kyung-Hee;Kim, Jin-Ju;Kim, Young-Hwa;Huh, Kyung-Hye;Song, Young-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.3
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    • pp.276-283
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    • 2007
  • This study was carried out to investigate the effect of isoflavone on the atherogenic effect in C57BL/6 mice. C57BL/6 female mice, 5 weeks of age, were fed on chow diets for 2 weeks during adjustment period. Mice weighing approximately $17.9{\pm}0.9\;g$ were divided into 4 groups and were fed on the experimental diets containing isoflavone for 8 weeks. Experimental groups were control (atherogenic diet), IF-10 (atherogenic diet with isoflavone 10 mg/100 g diet), IF-40 (atherogenic diet with isoflavone 40 mg/100 g diet) and IF-100 (atherogenic diet with isoflavone 100 mg/100 g diet). Food efficiency ratio was not different among the experimental groups. Plasma triglyceride (TG) concentrations were lower after 4 weeks in isoflavone supplementation groups than in control group, whereas monocyte chemoattractant protein-1 and thiobarbituric acid reactive substances (TBARS) levels of plasma were significantly (p<0.05) decreased in the isoflavone supplementation groups in a dose dependent manner. Both hepatic TG and cholesterol levels were significantly lowered in IF-100 than control. Hepatic glutathione concentrations were higher in the IF-100 group than in the other groups. Hepatic antioxidant enzyme activities including glutathione-reductase, glutathione-peroxidase, catalase, and Mn-superoxide dismutase were significantly higher in the isoflavone supplemen-tation groups in a dose dependent manner. From the above results, it is concluded that isoflavone may reduce the risk of atherosclerosis via hypolipidemic, anti-oxidative and anti-inflammatory effects.

Development of Overhead Projector Films, CD-ROM, and Bio-Cosmos Home Page as Teaching Resources for High School Biology (고교 생물의 오버헤드 프로젝터용 필름 제작 및 전달 매체로서의 CD-ROM과 홈페이지의 설계)

  • Song, Bang-Ho;Sin, Youn-Uk;Choi, Mie-Sook;Park, Chang-Bo;Ahn, Na-Young;Kang, Jae-Seuk;Kim, Jeung-Hyun;Seo, Hae-Ae;Kwon, Duck-Kee;Sohn, Jong-Kyung;Chung, Hwa-Sook;Yang, Hong-Jun;Park, Sung-Ho
    • Journal of The Korean Association For Science Education
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    • v.19 no.3
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    • pp.428-440
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    • 1999
  • The colorful overhead projector films, named as Bio-cosmos II, including photographs, pictures, concept maps, and diagrams, were developed and manufactured as audio-visual teaching aids and teaching resources for students' biology learning in high school, and the CD-ROM and web sites for their application to the school were also constructed. The content of the films was organized based upon the analysis of seven different biology textbooks approved by the Ministry of Education. The films were designated based on various instructional strategies and manufactured using multimedia with various educational softwares. The CD-ROM was composed of the scenes as logo, initial main, chapters list, contents, and quit. Initial main scene indicated various chapters according to the texts of biology areas in General Science, Biology I, and II. Each chapters linked with the scenes for detailed concept maps, the downstream real subjects, and contents. The subject screens were composed of various types of summarized diagrams including lesson contents, figures, pictures, photographs, and their explanation, experimental procedures and results, tables for summarized contents, and additional animation with video captures, explanations, glossary, etc. Most files were manufactured in software Adobe Photoshop by scanning the pictures, figures and photographs, and then the explanation, modification, storing with PICT or PSD files, and transformation with JPG files, were processed in the aspect of high quality in terms of instructional strategies and graphic skills on gracefulness, clearness, colorfulness, brightness, and distinctness. A 14 films for biology areas in General Science, 80 for Biology I, and 142 for Biology II were manufactured and loaded to the CD-ROM and web site, and the files had been attempted to opened with an internet home-page of http://gic.kyungpook.ac.kr/biocosmos.

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Field Application Techniques of Simultaneous Mating Disruptor Against Grapholita molesta and G. dimorpha (복숭아순나방과 복숭아순나방붙이에 대한 동시 교미교란제의 현장 적용 기술)

  • Cho, Jum-Rae;Park, Chang-Gyu;Park, Il-Kweon;Kim, Yonggyun
    • Korean journal of applied entomology
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    • v.57 no.3
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    • pp.209-220
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    • 2018
  • Mating disruption (MD) has been widely used to effectively control Grapholita molesta in apple orchards. A simultaneous mating disruption (SMD) techniques have been developed to control both G. molesta and G. dimorpha. This study was performed to determine the practical parameters to apply the SMD technique to field conditions. To determine the application amount of SMD lures, a dispenser containing 10 mg pheromone was placed at different numbers of trees in an orchard. Application at every other tree (= one dispenser per two trees) was relatively safe to expect effective MD efficiency in both wax and polyethylene (PE) formulations. One time application at the end of March was enough to maintain a year round MD efficacy against both species. A fence treatment using food trap was applied to prevent any immigratory mated females from nearby untreated regions. To enhance the food trap by adding host-derived secondary compounds, terpinyl acetate (TA) was screened to be effective to attract females of Grapholita molesta among six compounds contained in apple fruit extracts. Among different TA concentrations, 0.05% TA treatment was the most effective to attract the adults. A mixture of TA and sugar was effective to attract and kill females and called FAKT (female attract-to-kill techniques). FAKT was treated at approximately 6 m interval at the edge of the apple orchards. The females trapped by the FAKT included mated females possessing vitellogenic oocytes. SMD supplemented with FAKT maintained the high MD efficacy and significantly suppressed leaf damage induced by the two insect pests compared to control or single SMD treatment.