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A Self‑Regenerable Fiber Sloughing Its Heavy Metal Skin for Ultrahigh Separation Capability

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Advanced Fiber Materials 2023年第6期5卷 2127-2142页

作者： Youngkyun Jung Ji Su Park Kyung‑Won Jung Young gun Ko Jae‑woo Choi Center for Water Cycle Research Korea Institute of Science and TechnologySeoul 02792Republic of Korea Center for Bionics Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Chemical Engineering and Materials Science Sangmyung UniversitySeoul 03016Republic of Korea Division of Energy&Environment Technology KIST SchoolKorea University of Science and Technology(UST)Seoul 02792Republic of Korea

Developing efficient separation materials for recovering metal resources from aqueous environments is crucial for the sustainable water–food–energy nexus,which addresses the interdependence between energy production,water production,and energy *** material-based separation processes have demonstrated outstanding ***,electric energy and chemicals are used to frequently replace the separation materials used in such processes owing to their short life *** study presents a methodology for designing the self-regenerable fiber(SRF)according to the types of metals through a self-regeneration *** SRF can semi-permanently recover the metal resources from water through a repetitive adsorption–crystallization–detachment process of metal ions on its *** ionic metal resources are adsorbed and crystallized with the counter-anions on the SRF ***,the metal crystals are self-detached from the SRF surface by the collision between the crystals and curvature and non-sticky surface of the ***,a module containing the SRF maintains its metal recovery capability even during continuous injection of the metal solution without its *** findings highlight the significance of interfacial engineering and further guide the rational design of energy/environmentally friendly resource recovery modules.

关键词： Self-regeneration model Self-regenerable fiber Semi-permanent adsorption capability Metal crystal growth-detachment

Effect of ammonia gas etching on growth of vertically aligned carbon nanotubes/nanofibers

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 130-134页

作者： Sang-Gook kim Sooh-Yung kim Hyung-woo LEE Department of Mechanical Engineering Massachusetts Institute of Technology 77 Massachusetts Ave Cambridge MA 02139 USA National Core Research Center for Hybrid Materials Solution Pusan National University

The etching effect of ammonia （NH3） on the growth of vertically aligned nanotubes/nanofibers （CNTs） was investigated by direct-current plasma enhanced chemical vapor deposition （DC-PECVD）. NH3 gas etches Ni catalyst layer to form nanoscale islands while NH3 plasma etches the deposited amorphous carbon. Based on the etching effect of NH3 gas on Ni catalyst, the differences of growing bundles of CNTs and single strand CNTs were discussed; specifically, the amount of optimal NH3 gas etching is different between bundles of CNTs and single strand CNTs. In contrast to the CNT carpet growth, the single strand CNT growth requires shorter etching time （5 min） than large catalytic patterns （10 rain） since nano dots already form catalyst islands for CNT growth. Through removing the plasma pretreatment process, the damage from being exposed at high temperature substrate occurring during the plasma generation time is minimized. High resolution transmission electron microscopy （HTEM） shows fishbone structure of CNTs grown by PECVD.

关键词： carbon nanotube ammonia etching nickel catalyst plasma enhanced chemical vapor deposition (PECVD)

High-power and long-life supercapacitive performance of hierarchical, 3-D urchin-like W18049 nanostructure electrodes

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Nano Research 2016年第3期9卷 633-643页

作者： Sangbaek Park Hyun-woo Shim Chan woo Lee Hee Jo Song Jae-Chan kim Dong-Wan kim Department of Materials Science and Engineering Seoul National University Seoul 151-744 Republic of Korea School of Civil Environmental and Architectural Engineering Korea University Seou1136-713 Republic of Korea

We report the facile, one-pot synthesis of 3-D urchin-like W18O49 nanostructures （U-WO） via a simple solvothermal approach. An excellent supercapacitive performance was achieved by the U-WO because of its large Brunauer-Emmett- Teller （BET） specific surface area （ca. 123 m2.g-1） and unique morphological and structural features. The U-WO electrodes not only exhibit a high rate-capability with a specific capacitance （Csp） of -235 F·g-1 at a current density of 20 A.g-1, but also superior long-life performance for 1,000 cycles, and even up to 7,000 cycles, showing -176 F·g-1 at a high current density of 40 A.g-1.

关键词： hierarchical structure W18O49 high-power long cycle life supercapacitor

HER2-induced metastasis is mediated by AKT/JNK/EMT signaling pathway in gastric cancer

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World Journal of Gastroenterology 2016年第41期22卷 9141-9153页

作者： Yiseul Choi Young San Ko Jinju Park Youngsun Choi Younghoon kim Jung-Soo Pyo Bo gun Jang Douk Ho Hwang woo Ho kim Byung Lan Lee Department of Tumor Biology Cancer Research Institute Seoul National Universit College of Medicine Department of Anatomy Seoul National University College of Medicine Department of Pathology Seoul National University College of Medicine Department of Pathology Eulji University Hospital Eulji University College of Medicine Department of Pathology Jeju National University Hospital Ischemic/Hypoxic Disease Institute Medical Research Center Seoul National University College of Medicine

AIM To investigated the relationships between HER2, c-Jun N-terminal kinase(JNK) and protein kinase B(AKT) with respect to metastatic potential of HER2-positive gastric cancer(GC) *** Immunohistochemistry was performed on tissue array slides containing 423 human GC specimens. Using HER2-positve GC cell lines SNU-216 and NCI-N87, HER2 expression was silenced by RNA interference, and the activations of JNK and AKT were suppressed by SP600125 and LY294002, respectively. Transwell assay, Western blot, semi-quantitative reverse transcriptionpolymerase chain reaction and immunofluorescence staining were used in cell culture experiments. RESULTS In GC specimens, HER2, JNK, and AKT activations were positively correlated with each other. In vitro analysis revealed a positive regulatory feedback loop between HER2 and JNK in GC cell lines and the role of JNK as a downstream effector of AKT in the HER2/AKT signaling pathway. JNK inhibition suppressed migratory capacity through reversing EMT and dual inhibition of JNK and AKT induced a more profound effect on cancer cell *** HER2, JNK and AKT in human GC specimens are positively associated with each other. JNK and AKT, downstream effectors of HER2, co-operatively contribute to the metastatic potential of HER2-positive GC cells. Thus, targeting of these two molecules in combination with HER2 downregulation may be a good approach to combat HER2-positive GC.

关键词： Gastric cancer HER2 c-Jun N-terminal kinase Protein kinase B Metastatic potential

Segregation of voiced and unvoiced components from residual of speech signal

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Journal of Central South University 2012年第2期19卷 496-503页

作者： JO Cheol-woo kim Jae-hee School of Mechatronics Changwon National University

In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture of two sources and the ratio varies according to the content or the intention of speaker. It had been investigated to separate the voiced and unvoiced components for different source models. Source signals were modeled based on the residual signal measured from inverse filtering. Three different source models were assumed. The parameters of each model were optimized for the original speech signal using a genetic algorithm. The resulting parameters were compared in terms of the mel-cepstral distance to the original signal, the spectrogram and the spectral envelope from the synthesized signal. The optimization method achieves an improvement of 15% for the Klatt model, but there is little improvement in the modified residual case.

关键词： voice source model synthesis optimization genetic algorithm

Multi-View Multi-Modal Head-Gaze Estimation for Advanced Indoor User Interaction

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Computers, Materials & Continua 2022年第3期70卷 5107-5132页

作者： Jung-Hwa kim Jin-woo Jeong Department of Computer Engineering Kumoh National Institute of TechnologyGumi39177Korea Department of Data Science Seoul National University of Science and TechnologySeoul01811Kore

Gaze estimation is one of the most promising technologies for supporting indoor monitoring and interaction ***,previous gaze estimation techniques generally work only in a controlled laboratory environment because they require a number of high-resolution eye *** makes them unsuitable for welfare and healthcare facilities with the following challenging characteristics:1)users’continuous movements,2)various lighting conditions,and 3)a limited amount of available *** address these issues,we introduce a multi-view multi-modal head-gaze estimation system that translates the user’s head orientation into the gaze *** proposed system captures the user using multiple cameras with depth and infrared modalities to train more robust gaze estimators under the aforementioned *** this end,we implemented a deep learning pipeline that can handle different types and combinations of *** proposed system was evaluated using the data collected from 10 volunteer participants to analyze how the use of single/multiple cameras and modalities affect the performance of head-gaze *** various experiments,we found that 1)an infrared-modality provides more useful features than a depth-modality,2)multi-view multi-modal approaches provide better accuracy than singleview single-modal approaches,and 3)the proposed estimators achieve a high inference efficiency that can be used in real-time applications.

关键词： Human-computer interaction deep learning head-gaze estimation indoor monitoring

Species delimitation in the green algal genus Codium (Bryopsidales) from Korea using DNA barcoding

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Acta Oceanologica Sinica 2015年第4期34卷 114-124页

作者： LEE Hyung woo kim Myung Sook Department of Biology Jeju National University

Codium, one of the largest marine green algal genera, is difficult to delimit species boundary accurately based on morphological identification only. DNA barcoding is a powerful tool for discriminating species of seaweeds. The plastid elongation factor TU （tufA） is considered as maker to perform DNA barcoding of green algal species than rbcL gene due to universality and rapid evolution rate. We conducted DNA barcoding application to Codium specimens from the Jeju Island, Korea to overcome the limit of morphological identification and to confirm the species diversity. As a result of applying tufA marker, we newly generated fifty-five tufA barcodes to resolve eight species. TufA marker exhibited 6.1%–21.8% interspecific divergences, wider than the gap of rbcL exon 1, 3.5%–11.5%. Molecular analysis of rbcL exon 1 sequences of Codium revealed eight distinct species like tufA analysis separated in five phylogenetic groups. DNA barcoding of the genus Codium using tufA marker is more helpful to overcome the limit of morphological identification, and this is more potential to reveal cryptic species and to resolve the relationships among subspecies than rbcL analysis alone. The complement of tufA barcoding and rbcL analyses including morphology for the genus Codium in the northwestern Pacific will give much more reliable achievement for discovering species diversity and resolving the phylogenetic relationships.

关键词： Codium DNA barcoding rbcL Species delimitation tufA

A facile synthesis of hierarchical Sn3O4 nanostructures in an acidic aqueous solution and their strong visible- light-driven photocatalytic activity

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Nano Research 2015年第11期8卷 3553-3561页

作者： Hui Song Su-Young Son Seul Ki kim gun Young Jung School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST) Gwangju 500-712 Republic of Korea Carbon Convergence Materials Research Center Institute of Advanced Composite Materials Korea Institute of Science and Technology (KIST) Jeollabuk-do 565-905 Republic of Korea

Hierarchical tin（Ⅲ） oxide, Sn3O4, nanospheres were synthesized via hydrothermal reaction under strongly acidic ambient conditions. The morphology of Sn3O4 varied with decreasing pH. The prickly SnaO4 nanospheres changed into SnaO4 nanospheres covered with single-crystalline nanoplates having a high BET surface area of ca. 55.05 m^2·g^-1 and a band gap of ca. 2.25 eV. Small amounts （0.05 g） of the hierarchical Sn3O4 nanostructures completely decomposed a 30% methyl orange （MO） solution in 100 mL deionized water within 15 min under one sun condition （UV ＋ visible light）. The Sn3O4 photocatalyst exhibited a fast decomposition rate of 1.73 ×10^-1 min^-1, which is a 90.86% enhancement relative to that of the commercially available P25 photocatalyst. The high photocatalytic activity of the hierarchical Sn3O4 nanostructures is attributed to its ability to absorb visible light and its high surface-to-volume ratio.

关键词： Sn3O4 hierarchical structure hydrothermal morphology engineering photocatalyst

Efficient electron extraction of SnO_(2) electron transport layer for lead halide perovskite solar cell

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npj Computational Materials 2020年第1期6卷 836-843页

作者： Junu kim Kwang S.kim Chang woo Myung Center for Superfunctional Materials Department of PhysicsSchool of Natural ScienceUlsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea Center for Superfunctional Materials Department of ChemistrySchool of Natural ScienceUlsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea

SnO_(2) electron transport layer(ETL)has been spotlighted with its excellent electron extraction and stability over TiO_(2) ETL for perovskite solar cells(PSCs),rapidly approaching the highest power conversion ***,how... 详细信息

关键词： ETL layer perovskite