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Modern Research in Catalysis 2014年第3期3卷 99-106页

作者： Suk-Hwan Kang Jae-Hong Ryu Jin-Ho Kim Hyo-Sik Kim chan-gi lee Yun-Jo lee Ki-Won Jun Petroleum Displacement Technology Research Center Korea Research Institute of Chemical Technology (KRICT) Yuseong Daejeon Korea Plant Engineering Center Institute for Advances Engineering (IAE) Yongin-si Korea

Fischer-Tropsch synthesis (FTS) reaction for the direct production of gasoline range hydrocarbons (C5-C9) from syngas was investigated on Ru, Pt, and La promoted Co/ZSM-5 (Si/Al = 25) catalysts. The hybrid catalysts were characterized by BET surface area, XRD, H2-TPR, NH3-TPD and XPS analyses. These physico-chemical properties were correlated with activity and selectivity of the catalysts. The promoted Co/ZSM-5 hybrid catalysts were found to be superior to the unpromoted Co/ZSM-5 catalyst in terms of better C5-C9 selectivity. Pt-Co/ZSM-5 exhibited the highest catalytic activity because of the small cobalt particle size.

关键词： Fischer-Tropsch Synthesis Cobalt Hybrid Catalyst Promoter Gasoline ZSM-5 Syngas

Bubble and Heat Transfer Phenomena in Viscous Slurry Bubble Column

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Advances in Chemical Engineering and Science 2014年第4期4卷 417-429页

作者： Hyo Sik Kim Jin Ho Kim chan gi lee Suk Hwan Kang Kwang Jae Woo Ho Jin Jung Dong Wook Kim Plant Engineering Center Institute for Advanced Engineering (IAE) Gyongki-do Korea DAEWOONG E & S Daejeon Korea Department of Environmental Engineering Kongju National University Cheonan Korea

Heat transfer and bubble phenomena were investigated by adopting the drift flux model in a viscous slurry bubble column reactor (SBCR), having a diameter of 0.0508 m(ID) and height 1.5 m. The effects of superficial gas velocity (0.002 -0.164 m/s), solid concentration (0 - 20 wt%) and liquid viscosity (paraffin oil;16.9 mPa•s and squalane;25.9 mPa•s) on the gas holdup and heat transfer characteristics were examined. It was observed that the gas holdup increased with increasing superficial gas velocity (UG), but decreased with increasing solid concentration (SC) or slurry viscosity. The degree of non-uniformity in a SBCR could be determined by the modified drift flux model at the heterogeneous flow regime. The local heat transfer coefficient (h) between the immersed heater and the bed decreased with increasing liquid viscosity and SC, but it increased with increasing UG. The modified Nusselt number including the gas holdup and local heat transfer coefficient was well correlated in terms of dimensionless groups such as Reynolds and Prandtl numbers.

关键词： Gas Holdup Slurry Bubble Column Heat Transfer Drift Flux Model

Effect of esterification reaction of citric acid and ethylene glycol on the formation of multi-shelled cobalt oxide powders with superior electrochemical properties

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Nano Research 2014年第12期7卷 1738-1748页

作者： gi Dae Park Jong-Heun lee Jung-Kul lee Yun chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea Department of Chemical Engineering Konkuk University 1 Hwayang-dong Gwangjin-gu Seou1143-701 Republic of Korea

In this study, for the first time, polymeric precursors have been used in the preparation of yolk-shell powders using a large-scale spray drying process. An esterification reaction between the carboxyl group of citric acid and the hydroxyl group of ethylene glycol inside the droplet produced organic polymers during the drying process of the droplet. During the spray drying process, the polymeric precursors enabled the formation of multi-shell cobalt oxide yolk- shell powders with superior electrochemical properties. The maximum number of shells of the particles in the yolk-shell powders post-treated at 300, 400, and 500 ℃ were six, five, and four, respectively. The initial discharge capacities of the cobalt oxide yolk-shell powders post-treated at 300, 400, and 500 ℃ were 1,188, 1,331, and 1,110 mAh·g^-1, and their initial charge capacities were 868, 1,005, and 798 mAh·g^-1, respectively. The discharge capacities of the powders post- treated at 300, 400, and 500 ℃ after 100 cycles were 815, 958, and 670 mAh·g^-1, respectively and their corresponding capacity retentions measured after the first cycles were 92%, 93%, and 82%, respectively. The pure phase Co3O4 yolk-shell powders post-treated at 400 ℃ had low charge transfer resistance and high lithium-ion diffusion rate.

关键词： yolk-shell energy storage synthesis design lithium battery spray drying

Quantitative analysis of mechanical properties associated with aging treatment and microstructure in Mg-Al-Zn alloys through machine learning

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Journal of Materials Science & Technology 2022年第12期107卷 52-63页

作者： Joung Sik Suh Byeong-chan Suh Sang Eun lee Jun Ho Bae Byoung gi Moon Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor *** this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine *** regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging *** simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous *** overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured *** neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of *** tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.

关键词： Magnesium alloy Aging treatment Microstructure Mechanical properties Machine learning

Fabrication of heteroatom-doped cobalt oxide yolk-shell microsphere using recycled solution from waste materials and their excellent electrochemical properties as an anode material for lithium-ion batteries

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Rare Metals 2024年第10期43卷 4934-4947页

作者： Yeong Beom Kim chanho Kim Seung-Hyun Kim Yun chan Kang Dongju lee gi Dae Park Department of Advanced Materials Engineering Chungbuk National UniversityChungbuk 28644Korea Department of Materials Science and Engineering Korea UniversitySeoul 136-713Korea Research Institute YKSintering Co.Ltd.Chungbuk 28581Korea

Heteroatom-doped transition metal oxides have attracted great attention as advanced anode materials for lithium-ion batteries due to their high theoretical capacity and superior ***,the limited resource availability has led to a substantial rise in prices for valuable metals such as Ni and Co,posing a significant challenge for their *** address this issue,recycling of these metals from waste materials have gained prominence,and particularly the recovery of Co has been mostly focused on its economic ***,we introduced a novel recycling strategy for fabrication of heteroatomdoped CoO_(x)(comprising mainly Co_(3)O_(4)with a minor CoO phase)anode with a yolk–shell structure for lithium-ion batteries,by separating Co from cemented tungsten carbide *** employing a simple leaching process and subsequent spray pyrolysis,the yolk–shell structured microsphere comprising CoO_(x)was successfully ***,the presence of other waste metals in the leachate facilitated multi-heteroatom doping during ***,the introduction of various dopants into CoO_(x)induced oxygen vacancy formation,thereby enhancing the electrochemical properties of the CoO_(x)*** a result,compared with the phase-pure(undoped)CoO_(x)yolk–shell,the heteroatom-doped CoO_(x)yolk–shell exhibited robust cycling stability(602 mAh·g^(-1)for 200 cycles at 1 A·g^(-1))and excellent rate capability(210 mAh·g^(-1)at 10 A·g^(-1)).

关键词： Recycling Heteroatom doping Cobalt oxide Anode Lithium-ion batteries

Creep and tensile properties of press molding joined GMT-sheets

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 170-174页

作者： Jin-Woo KIM Dong-gi lee Center for NDE Iowa State University Department of Mechatronics Engineering Chosun University

GMT-sheet is used in automobile bumper with high rigidity and strength, and its joining strength is influenced by lap length, one of the joined molding conditions. Fracture strength was calculated by dividing fracture load with cross-sectional area. Total five repeated measurements were made to obtain the average value. Tensile test was conducted at room temperature for 10 specimens. In addition, the effect of compression ratio on creep and tensile performance during lap joined molding was discussed. With increasing lap length, the lap joining efficiency of GMT-sheet was increased. However, higher compression ratio reduced the joining efficiency. Creep test on GMT-sheet showed abrupt fracture without tertiary creep. This can be explained by the weak thermal resistance of the resin. If GMT-sheet was exposed to high temperature for a long time, it was easily failed by external force.

关键词： GMT-sheet randomly oriented composite unidirectional oriented composite compression ratio lap joint

Gene editing of authentic Brassica rapa flavonol synthase 1 generates dihydroflavonol-accumulating Chinese cabbage

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Horticulture Research 2023年第12期10卷 58-69页

作者： Sangkyu Park Hyo lee Jaeeun Song chan Ju Lim Jinpyo Oh Sang Hoon lee Saet Buyl lee Jong-Yeol lee Sunhyung Lim Jin A.Kim Beom-gi Kim Metabolic Engineering Division National Institute of Agricultural SciencesRural Development AdministrationJeonju54874South Korea Institute of Biotechnology and Breeding Asiaseed Inc.Icheon17414South Korea Food and Nutrition Division National Institute of Agricultural SciencesRural Development AdministrationWanju55365South Korea Department of Horticultural Biotechnology School of BiotechnologyHankyong National UniversityAnseong17579South Korea

Flavonols are the major class of flavonoids of green Chinese cabbage(Brassica rapa ***).The *** genome harbors seven flavonol synthase genes(BrFLSs),but they have not been functionally ***,transcriptome analysis showed four BrFLSs mainly expressed in Chinese *** them,only BrFLS1 showed major FLS activity and additional flavanone 3β-hydroxylase(F3H)activity,while BrFLS2 and BrFLS3.1 exhibited only marginal F3H *** generated BrFLS1-knockout(BrFLS1-KO)Chinese cabbages using CRISPR/Cas9-mediated genome editing and obtained transgene-free homozygous plants without off-target mutation in the T1 generation,which were further advanced to the T2 generation showing normal ***-ESI-QTOF-MS analysis revealed that flavonol glycosides were dramatically decreased in the T2 plants,while dihydroflavonol glycosides accumulated concomitantly to levels corresponding to the reduced levels of *** PCR analysis revealed that the early steps of phenylpropanoid and flavonoid biosynthetic pathway were upregulated in the BrFLS1-KO *** accordance,total phenolic contents were slightly enhanced in the BrFLS1-KO plants,which suggests a negative role of flavonols in phenylpropanoid and flavonoid biosynthesis in Chinese *** surveys revealed that the BrFLS1-KO Chinese cabbages showed normal head formation and reproductive phenotypes,but subtle morphological changes in their heads were *** addition,their seedlings were susceptible to osmotic stress compared to the controls,suggesting that flavonols play a positive role for osmotic stress tolerance in *** *** this study,we showed that CRISPR/Cas9-mediated BrFLS1-KO successfully generated a valuable breeding resource of Chinese cabbage with distinctive metabolic traits and that CRISPR/Cas9 can be efficiently applied in functional Chinese cabbage breeding.

关键词： steps slightly phenolic

Meta Shack–Hartmannwavefront sensor with large sampling density and large angular field of view:phase imaging of complex objects

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Light(Science & Applications) 2024年第9期13卷 1908-1918页

作者： gi-Hyun Go Dong-gu lee Jaeyeon Oh Gookho Song Doeon lee Mooseok Jang Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology(KAIST)DaejeonRepublic of Korea

Shack–Hartmann wavefront sensors measure the local slopes of an incoming wavefront based on the displacement of focal spots created by a lenslet array,serving as key components for adaptive optics for astronomical and biomedical ***,the challenges in increasing the density and the curvature of the lenslet have limited the use of such wavefront sensors in characterizing slowly varying wavefront ***,we develop a metasurfaceenhanced Shack–Hartmann wavefront sensor(meta SHWFS)to break this limit,considering the interplay between the lenslet parameters and the performance of *** experimentally validate the meta SHWFS with a sampling density of 5963 permm2 and a maximum acceptance angle of 8°which outperforms the traditional SFWFS by an order of ***,to the best of our knowledge,we demonstrate the first use of a wavefront sensing scheme in single-shot phase imaging of highly complex patterns,including biological tissue *** proposed approach opens up new opportunities in incorporating exceptional light manipulation capabilities of the metasurface platform in complex wavefront characterization.

关键词： angular curvature exceptional

Autonomous Optimal Coordination Scheme in Protection System of Power Distribution Network by Using Multi-Agent Concept

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Transactions of Tianjin University 2008年第2期14卷 106-111页

作者： lee Seung-Jae KIM Tae-Wan lee gi-Young Next-Generation Power System Technology Center Myongji UniversityYongin449-728KyunggidoKorea

A protection system using a multi-agent concept for power distribution networks is *** digital over current relay(OCR)is developed as an agent by adding its own intelligence,self-tuning and communication *** main advantage of the multi-agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual *** order to cope with frequent changes in the network operation condition and faults,an OCR agent,proposed in this paper,is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other *** this kind of coordination and information exchanges,not only a local but also a global protective scheme is *** in a simple distribution network show the effectiveness of the proposed protection system.

关键词： multi-agent system over current relay(OCR) communication protection of distribution network

Surgical repair of intractable chylous ascites following laparoscopic anterior resection

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World Journal of Gastroenterology 2015年第19期21卷 6077-6081页

作者： gi Won Ha Min Ro lee Research Institute of Clinical Medicine Chonbuk National University Medical School

Chylous ascites is the accumulation of a milk-like peritoneal fluid rich in triglycerides and it is an unusual complication following surgical treatment of colorectal cancer. Conservative management is usually sufficientin patients with chylous ascites after surgery. However,we describe a patient with intractable chylous ascites after laparoscopic anterior resection for sigmoid colon cancer who failed initial conservative treatment. This patient was successfully managed by surgery.

关键词： Sigmoid colon cancer Laparoscopy Anteriorresection Chylous ascites Surgical repair