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Effects of Hybrid Voltages on Oxide Formation on 6061 Al-alloys During Plasma Electrolytic Oxidation

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Chinese Journal of Aeronautics 2009年第5期22卷 564-568页

作者： Kai Wang Bon Heun Koo Chan Gyu Lee young joo kim Sunghun Lee Eungsun Byon School of Nano & Advanced Materials Engineering Changwon National University Changwon 641-773 Korea Surface Technology Research Center Korea Institute of Materials Science Changwon 641-010 Korea

Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X-ray diffration （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometry （EDS） are conducted on the specimens, which have been PEO-treated under hybrid voltages of different direct current （DC） values （140-280 V） with constant alternate current （AC） amplitude （200 V）. Attention is paid to the composition, properties and growth mechanism of oxide layers formed with hybrid voltages. Moreover, the main effects of DC value are discussed. Ceramic layers with a double-layer structure which combines hard outer and soft inner layers are found to be consist of α-Al2O3,γ-Al2O3 and mullite. With the DC values increasing, the growth of the ceramic layers tends to have increasingly obvious three-stage feature.

关键词： plasma electrolytic oxidation oxide layer aluminum alloys alkaline electrolyte hybrid voltages

Effects of electrolytes variation on formation of oxide layers of 6061 Al alloys by plasma electrolytic oxidation

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中国有色金属学会会刊：英文版 2009年第4期19卷 866-870页

作者： Kai WANG Bon-Heun KOO Chan-Gyu LEE young-joo kim Sung-Hun LEE Eungsun BYON School ofNano ＆ Advanced Materials Engineering Changwon National University Changwon 641-773 Korea Surface Technology Research Center Korea Institute of Materials Science Changwon 641-010 Korea

Plasma electrolytic oxidation(PEO) processes were carried out to produce ceramic layers on 6061 aluminum substrates in four kinds of electrolytes such as silicate and aluminate solution with and without sodium *** PEO processes were carried out under a hybrid voltage(260 V DC combined with 200 V,60 Hz AC amplitude) at room temperature for 5 *** composition,microstructure and element distribution analyses of the PEO-treated layers were carried out by XRD and SEM & *** effect of the electrolyte contents on the growth mechanism,element distribution and properties of oxide layers were *** is obvious that the layers generated in aluminate solutions show smoother surfaces than those in silicate ***,an addition of fluorine ion can effectively control the layer porosity;therefore,it can enhance the properties of the layers.

关键词：等离子电解氧化 6061合金氧化层对格质变等离子体电解氟硅酸钠铝酸钠溶液

Indolocarbazole-Based Small Molecule Cathode-Active Material Exhibiting Double Redox for High-Voltage Li-Organic Batteries

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Energy & Environmental Materials 2024年第5期7卷 90-98页

作者： Hyunji Park Hyojin Kye Jong-Sung Lee young-Chang joo Dong joo Min Bong-Gi kim Soo young Park Ji Eon Kwon Laboratory for Supramolecular Optoelectronic Materials (LSOM) Department of Materials Science and Engineering Research Institute of Advanced Materials (RIAM) Seoul National University Functional Composite Materials Research Center Jeonbuk Institute of Advanced Composite Materials Korea Institute of Science and Technology (KIST) Department of Organic and Nano System Engineering Konkuk University Department of Materials Science and Engineering Seoul National University Department of JBNU-KIST Industry Academia Convergence Research Jeonbuk National University

Most organic electrode materials （OEMs） for rechargeable batteries employ n-type redox centers, whose redox potentials are intrinsically limited <3.0 V versus Li+/Li. However, p-type materials possessing high redox potentials experience low specific capacities because they are capable of only a single redox reaction within the stable electrochemical window of typical ***, we report 5,11-diethyl-5,11-dihydroindolo[3,2-b]carbazole （DEICZ） as a novel p-type OEM, exhibiting stable plateaus at high discharge potentials of3.44 and 4.09 V versus Li+/Li. Notably, the second redox potential of DEICZ is within the stable electrochemical window. The mechanism of the double redox reaction is investigated using both theoretical calculations and experimental measurements, including density functional theory calculations, ex situ electron spin resonance, and X-ray photoelectron spectroscopy. Finally,hybridization with single-walled carbon nanotubes （SWCNT） improves the cycle stability and rate performance of DEICZ owing to theπ–πinteractions between the SWCNT and co-planar molecular structure of DEICZ, preventing the dissolution of active materials into the electrolyte. The DEICZ/SWCNT composite electrode maintains 70.4%of its initial specific capacity at 1-C rate and also exhibits high-rate capability, even performing well at 100-C rate.

关键词： composite electrodes flexible batteries indolocarbazoles organic rechargeable batteries p-type

SUMS OF DUAL TOEPLITZ PRODUCTS ON THE ORTHOGONAL COMPLEMENTS OF FOCK-SOBOLEV SPACES

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Acta Mathematica Scientia 2024年第3期44卷 810-822页

作者：陈泳 young joo Lee Department of Mathematics Hangzhou Normal UniversityHangzhou311121China Department of Mathematics Chonnam National UniversityGwangju61186Korea

We consider dual Toeplitz operators on the orthogonal complements of the FockSobolev spaces of all nonnegative real ***,for symbols in a certain class containing all bounded functions,we study the problem of when an operator which is finite sums of the dual Toeplitz products is compact or ***,for bounded symbols,we construct a symbol map and exhibit a short exact sequence associated with the C^(*)-algebra generated by all dual Toeplitz operators with bounded symbols.

关键词： dual Toeplitz operators Fock-Sobolev spaces symbol map

Programmable directional color dynamics using plasmonics

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Microsystems & Nanoengineering 2024年第1期10卷 325-334页

作者： Gyurin kim Doeun kim Soeun Ko Jang-Hwan Han Juhwan kim joo Hwan Ko young Min Song Hyeon-Ho Jeong School of Electrical Engineering and Computer Science Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Department of Semiconductor Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Artificial Intelligence(AI)Graduate School Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual ***,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural ***,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer *** nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission ***,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible ***,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

关键词： directional prevailing exceptional

Stable immobilization of lithium polysulfides using three-dimensional ordered mesoporous Mn_(2)O_(3) as the host material in lithium-sulfur batteries

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Carbon Energy 2024年第6期6卷 99-112页

作者： Sung joon Park Yun Jeong Choi Hyun-seung kim Min joo Hong Hongjun Chang Janghyuk Moon young-Jun kim Junyoung Mun Ki Jae kim Department of Energy Science Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea Department of Energy Engineering Konkuk UniversitySeoulRepublic of Korea Advanced Batteries Research Center Korea Electronic Technology InstituteSeongnamRepublic of Korea Department of Future Energy Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Department of Energy Systems Engineering Chung-Ang UniversitySeoulRepublic of Korea SKKU Advanced Institute of Nanotechnology Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwonRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwonRepublic of Korea

Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy ***,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical *** this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle ***-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain *** OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g^(-1) after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g^(-1) even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g^(-1)).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.

关键词： host material lithium-sulfur battery ordered mesoporous structure shuttle effect transition-metal oxides

Advancements in hemostatic strategies for managing upper gastrointestinal bleeding: A comprehensive review

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World Journal of Gastroenterology 2024年第15期30卷 2087-2090页

作者： Ah young Lee joo young Cho Division of Gastroenterology Department of Internal MedicineCha Gangnam Medical CenterCha University College of MedicineSeoul 06135Korea

Upper gastrointestinal(GI)hemorrhage presents a substantial clinical *** management typically involves resuscitation and endoscopy within 24 h,although the benefit of very early endoscopy(<12 h)for high-risk patients is *** goals include stopping acute bleeding,preventing rebleeding,and using a multimodal approach encompassing endoscopic,pharmacological,angiographic,and surgical *** agents such as vasopressin,prostaglandins,and proton pump inhibitors are effective,but the increase in antithrombotic use has increased GI bleeding *** hemostasis,particularly for nonvariceal bleeding,employs techniques such as electrocoagu-lation and heater probes,with concerns over tissue injury from monopolar *** methods such as Hemospray and Endoclot show promise in creating mechanical tamponades but have ***,the first-line therapy includes thermal probes and hemoclips,with over-the-scope clips emerging for larger ulcer *** gold probe,combining bipolar electrocoagulation and injection,offers targeted coagulation but has faced device-related *** advancements involve combining techniques and improving endoscopic imaging,with studies exploring combined approaches showing *** research is crucial for developing standardized and effective hemorrhage management strategies.

关键词： Upper gastrointestinal bleeding Hemostasis Endoscopy Probe Spray Clip

Intraductal papillary bile duct adenocarcinoma and gastrointestinal stromal tumor in a case of neurofibromatosis type 1

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World Journal of Gastroenterology 2018年第4期24卷 537-542页

作者： Jung Min Lee Jae Min Lee Jong Jin Hyun Hyuk Soon Choi Eun Sun kim Bora Keum Yoon Tae Jeen Hoon Jai Chun Hong Sik Lee Chang Duck kim Dong Sik kim joo young kim Division of Gastroenterology and Hepatology Department of Internal Medicine Institute of Gastrointestinal Medical Instrument Research Korea University College of Medicine Division of Gastroenterology and Hepatology Department of Internal Medicine Korea University Anam Hospital Division of HBP Surgery and Liver Trans- plantation Department of Surgery Korea University College of Medicine Department of Pathology Korea University College of Medicine

We report our experience with a synchronous case of gastrointestinal stromal tumor(GIST) and intraductal papillary neoplasm of the bile duct(IPNB) in anelderly woman with neurofibromatosis type 1(NF-1). A 72-year-old woman presented with a 2-mo history of right upper abdominal pain unrelated to diet and indigestion. Fourteen years earlier, she had been diagnosed with NF-1, which manifested as café au lait spots and multiple nodules on the skin. Computed tomography(CT) revealed a multilocular low-density mass with septation, and mural nodules in the right hepatic lobe, as well as a 1.7-cm-sized well-demarcated enhancing mass in the third portion of the duodenum. The patient subsequently underwent right hepatectomy and duodenal wedge resection. We present here the first report of a case involving a synchronous IPNB and GIST in a patient with NF-1. Our findings demonstrate the possibility of various tumors in NF-1 patients and the importance of diagnosis at an early

关键词： Neurofibromatosis type 1 Intraductal papillary neoplasm of the bile duct Gastrointestinal stromal tumor Synchronous

Disordered Structure and Reversible Phase Transformation from K-Birnessite to Zn-Buserite Enable High-Performance Aqueous Zinc-lon Batteries

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Energy & Environmental Materials 2024年第3期7卷 100-111页

作者： Nibagani Naresh Suyoon Eom Sang Jun Lee Su Hwan Jeong Ji-Won Jung young Hwa Jung joo-Hyung kim Department of Materials Engineering and Convergence Technology Gyeongsang National University(GNU)Jinju 52828South Korea School of Material Science and Engineering(Ceramic Engineering) Gyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering University of Ulsan(UOU)Ulsan 44776South Korea PLS-ⅡBeamline Division Pohang Accelerator Laboratory(PAL)Pohang 37673South Korea

The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity *** this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal *** degree of disorderness increases owing to the hetero-atom doping and graphene oxide *** is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered *** GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O ***,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.

关键词： aqueous zinc-ion batteries birnessite buserite disordered structure phase transformation