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Thermal stress analysis method considering geometric effect of risers in sand mold casting process 被引量:1
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作者 S.Y.Kwak H.Y.Hwang C.Cho 《China Foundry》 SCIE CAS 2014年第6期531-536,共6页
Solidif ication and f luid f low analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to contro... Solidif ication and f luid f low analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to control the defects related to thermal stresses, such as large deformation and crack generation during casting. The riser system is an essential part of preventing the shrinkage defects in the casting process, and it has a great inf luence on thermal phenomena. The analysis domain is dramatically expanded by attaching the riser system to a casting product due to its large volume, and it makes FEM mesh generation diff icult. However, it is diff icult to study and solve the above proposed problem caused by riser system using traditional analysis methods which use single numerical method such as FEM or FDM. In this paper, some research information is presented on the effects of the riser system on thermal stress analysis using a FDM/FEM hybrid method in the casting process simulation. The results show the optimal conditions for stress analysis of the riser model in order to save computation time and memory resources. 展开更多
关键词 thermal stress sand mold casting RISER numerical analysis hybrid method simulation
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Investigation of the sodium storage mechanism of iron fluoride hydrate cathodes using X-ray absorption spectroscopy and mossbauer spectroscopy
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作者 Ghulam Ali Muhammad Akbar +4 位作者 Faiza Jan Iftikhar Qamar Wali Beata Kalska Szostko Dariusz Satuła Kyung Yoon Chung 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期535-542,I0014,共9页
Elucidation of a reaction mechanism is the most critical aspect for designing electrodes for highperformance secondary batteries.Herein,we investigate the sodium insertion/extraction into an iron fluoride hydrate(FeF_... Elucidation of a reaction mechanism is the most critical aspect for designing electrodes for highperformance secondary batteries.Herein,we investigate the sodium insertion/extraction into an iron fluoride hydrate(FeF_(3)·0.5H_(2)O)electrode for sodium-ion batteries(SIBs).The electrode material is prepared by employing an ionic liquid 1-butyl-3-methylimidazolium-tetrafluoroborate,which serves as a reaction medium and precursor for F^(-)ions.The crystal structure of FeF_(3)·0.5H_(2)O is observed as pyrochlore type with large open 3-D tunnels and a unit cell volume of 1129A^(3).The morphology of FeF_(3)·0.5H_(2)O is spherical shape with a mesoporous structure.The microstructure analysis reveals primary particle size of around 10 nm.The FeF_(3)·0.5H_(2)O cathode exhibits stable discharge capacities of 158,210,and 284 mA h g^(-1) in three different potential ranges of 1.5-4.5,1.2-4.5,and 1.0-4.5 V,respectively at 0.05 C rate.The specific capacities remained stable in over 50 cycles in all three potential ranges,while the rate capability was best in the potential range of 1.5-4.5 V.The electrochemical sodium storage mechanism is studied using X-ray absorption spectroscopy,indicating higher conversion at a more discharged state.Ex-situ M?ssbauer spectroscopy strengthens the results for reversible reduction/oxidation of Fe.These results will be favorable to establish high-performance cathode materials with selective voltage window for SIBs. 展开更多
关键词 Iron fluoride Sodium-ion batteries PYROCHLORE X-ray absorption spectroscopy Mössbauer spectroscopy
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Near-infrared studies of nova V5584 Sgr in the pre-maximum and early decline phase
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作者 Ashish Raj D.P.K.Banerjee +1 位作者 N.M.Ashok Sang Chul KIM 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第7期993-1004,共12页
We present near-infrared spectroscopic and photometric observations of nova V5584 Sgr taken during the first 12 d following its discovery on Oct. 26.439 UT2009. The evolution of the spectra is shown from the initial P... We present near-infrared spectroscopic and photometric observations of nova V5584 Sgr taken during the first 12 d following its discovery on Oct. 26.439 UT2009. The evolution of the spectra is shown from the initial P Cygni phase to an emission line phase. The prominent carbon lines seen in the JHK spectra closely match those observed in an Fe II class nova outburst. The spectra show first-overtone CO bands in emission between 2.29-2.40 μm. By examining WISE and other publicly available data, we show that the nova underwent a pronounced dust formation phase between February- April 2010. 展开更多
关键词 line: identification -- techniques: spectroscopic -- stars: individual(V5584 Sgr) -- novae cataclysmic variables
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Experimental test of an extension of the Rosenzweig-Porter model to mixed integrable-chaotic systems experiencing time-reversal invariance violation
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作者 Xiaodong Zhang Jiongning Che Barbara Dietz 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第12期203-213,共11页
We report on the theoretical and experimental investigations of the transition of a typical quantum system with mixed regular-integrable classical dynamics to one with violated time-reversal(T)invariance.The measureme... We report on the theoretical and experimental investigations of the transition of a typical quantum system with mixed regular-integrable classical dynamics to one with violated time-reversal(T)invariance.The measurements are performed with a flat superconducting microwave resonator with circular shape in which chaoticity is induced by using either long antennas or inserting two circular disks into the cavity,and by magnetizing a ferrite disk placed at its center,which leads to violation of T invariance.We propose an extension of the Rosenzweig-Porter(RP)model,which interpolates between mixed regular-chaotic instead of integrable dynamics and fully chaotic dynamics with violated T-invariance,and derive a Wigner-surmise like analytical expression for the corresponding nearest-neighbor spacing distribution.We propose a procedure involving this result and those for the RP model to determine the size of T-invariance violation and chaoticity and validate it employing the experimental eigenfrequency spectra. 展开更多
关键词 wave chaos quantum chaos quantum billiards microwave billiards random matrix theory microwave experiments
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Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells
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作者 Inhyeok Cho Jiwon Yun +4 位作者 Boseok Seong Junseok Kim Sun Hee Choi Ho-Il Ji Sihyuk Choi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期1-9,I0001,共10页
PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula... PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated. 展开更多
关键词 Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy
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Post-impact lake environment changes in the Hapcheon impact crater,Korea
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作者 Jaesoo Lim Sujeong Park +1 位作者 Arum Jung Sung Won Kim 《Episodes》 2024年第3期477-496,共20页
The recently confirmed Hapcheon impact crater in Korea is a complex impact structure 7 km in diameter,with clear rims and impact-driven underground lacustrine sedimentary features.We investigated the lithological feat... The recently confirmed Hapcheon impact crater in Korea is a complex impact structure 7 km in diameter,with clear rims and impact-driven underground lacustrine sedimentary features.We investigated the lithological features of deposits within the impact crater using drilled sedimentary cores(23HIC01,20CR05,20CR09,and 20CR10),which consisted of an ascending order of impact breccias,lake sediments,and subaerial(e.g.,wetland)sediments.The impact breccia deposits in the 20CR05 and 23HIC01 cores contain shatter cones,which are a macroscopic indication of a meteorite impact.The overlying lake sediments were divided into three stages.The early stage of the post-impact lake environment corresponded to the lowermost lake sediments with frequent microfaults and slump-turbidite events.This stage is characterized by high calcite content of up to 13%.The middle stage showed a stable depositional environment,with silty to sandy lamination and bedding,and fewer microfaults.The final stage of the post-impact lake environment appears to have been very short and dramatic.This ended with the final slumping event,which appears to have been triggered by an abrupt outburst of lake water.This study demonstrates early post-impact lake sedimentation processes and crater instability in terms of soft-sediment deformation structures(e.g.,microfaults and slumps). 展开更多
关键词 shatter cone lithological features deposits hapcheon impact crater sedimentary cores hic cr cr impact breccia impact crater post impact lake environment impact structure
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Preparation of 2,5-Bis(Aminomethyl)Furan by Direct Reductive Amination of 2,5-Diformylfuran over Nickel-Raney Catalysts 被引量:4
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作者 Ngoc-Thuc Le Areum Byun +2 位作者 Yohan Han Kee-In Lee Hyungrok Kim 《Green and Sustainable Chemistry》 2015年第3期115-127,共13页
The direct reductive amination of 2,5-diformylfuran (DFF) with ammonia to 2,5-bis(aminomethyl)furan (BAF) was demonstrated, for the first time, over the commercial type Nickel-Raney and acid treated Nickel-Raney catal... The direct reductive amination of 2,5-diformylfuran (DFF) with ammonia to 2,5-bis(aminomethyl)furan (BAF) was demonstrated, for the first time, over the commercial type Nickel-Raney and acid treated Nickel-Raney catalysts. The effects of reaction parameters such as reaction medium, temperature and hydrogen pressure were described. The acid treated Nickel-Raney catalyst exhibited the highest BAF yield in the THF-water mixed reaction medium. The relatively higher Ni0 species composition and larger surface area of the acid treated Nickel-Raney catalyst with specific reaction conditions contributed greatly to the BAF formation. The oligomeric species, such as furanic imine trimers and tetramers confirmed by MALDI-MS analysis were presented as the intermediates of DFF reductive amination. 展开更多
关键词 Reductive Amination Primary Amine 2 5-Bis(Aminomethyl)Furan 5-Diformylfuran NICKEL RANEY Catalyst
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Facile Surface Functionalization of Electrospun Elastic Nanofibers Via Initiated Chemical Vapor Deposition for Enhanced Neural Cell Adhesion and Alignment
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作者 Yerim Jang Soonjong Roh +5 位作者 Younghak Cho Youngmee Jung Kangwon Lee Nakwon Choi Jin Yoo Hyejeong Seong 《Advanced Fiber Materials》 SCIE EI CAS 2024年第5期1583-1595,共13页
An advanced approach for functionalizing the surfaces of electrospun poly(l-lactide-co-ε-caprolactone)(PLCL)nanofibers for biomedical applications is presented here.Using initiated chemical vapor deposition(iCVD),a c... An advanced approach for functionalizing the surfaces of electrospun poly(l-lactide-co-ε-caprolactone)(PLCL)nanofibers for biomedical applications is presented here.Using initiated chemical vapor deposition(iCVD),a coating of the copolymer p(PFMA-co-DVB)containing poly(pentafluorophenyl methacrylate)(PFMA)and divinylbenzene(DVB)was applied to the PLCL nanofibers.This coating facilitated efficient immobilization of the biomolecules on the PLCL nanofiber surfaces,allowing precise adjustments to the polymer composition through modulation of the monomer flow rates.The resulting copolymer exhibited superior efficiency for immobilizing IgG,as confirmed by immunofluorescence intensity analysis.In vitro studies conducted with different neural cell types demonstrated that the laminin-coated iCVD-functionalized PLCL nanofibers maintained their inherent biocompatibility while significantly enhancing cell adhesion.By exploiting the elastic nature of the PLCL nanofibers,cell elongation could be successfully manipulated by controlling the nanofiber alignment,as demonstrated by scanning electron microscopy and quantification of the immunofluorescence image orientation.These findings highlight the potential of iCVD-modified PLCL nanofibers as versatile platforms for neural tissue engineering and various biomedical applications,allowing valuable biomaterial surface modifications for enhanced cellular interactions. 展开更多
关键词 Electrospun nanofiber Initiated chemical vapor deposition Poly(l-lactide-co-ε-caprolactone) Post-surface modification Neural cells
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Photonic control of ligand nanospacing in self-assembly regulates stem cell fate
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作者 Sungkyu Lee Jounghyun Yoo +39 位作者 Gunhyu Bae Ramar Thangam Jeongyun Heo Jung Yeon Park Honghwan Choi Chowon Kim Jusung An Jungryun Kim Kwang Rok Mun Seungyong Shin Kunyu Zhang Pengchao Zhao Yuri Kim Nayeon Kang Seong-Beom Han Dahee Kim Jiwon Yoon Misun Kang Jihwan Kim Letao Yang Solmaz Karamikamkar Jinjoo Kim Yangzhi Zhu Alireza Hassani Najafabadi Guosheng Song Dong-Hwee Kim Ki-Bum Lee Soong Ju Oh Hyun-Do Jung Hyun-Cheol Song Woo Young Jang Liming Bian Zhiqin Chu Juyoung Yoon Jong Seung Kim Yu Shrike Zhang Yongju Kim Ho Seong Jang Sehoon Kim Heemin Kang 《Bioactive Materials》 SCIE CSCD 2024年第4期164-180,共17页
Extracellular matrix(ECM)undergoes dynamic inflation that dynamically changes ligand nanospacing but has not been explored.Here we utilize ECM-mimicking photocontrolled supramolecular ligand-tunable Azo^(+)self-assemb... Extracellular matrix(ECM)undergoes dynamic inflation that dynamically changes ligand nanospacing but has not been explored.Here we utilize ECM-mimicking photocontrolled supramolecular ligand-tunable Azo^(+)self-assembly composed of azobenzene derivatives(Azo^(+))stacked via cation-πinteractions and stabilized with RGD ligand-bearing poly(acrylic acid).Near-infrared-upconverted-ultraviolet light induces cis-Azo^(+)-mediated inflation that suppresses cation-πinteractions,thereby inflating liganded self-assembly.This inflation increases nanospacing of“closely nanospaced”ligands from 1.8 nm to 2.6 nm and the surface area of liganded selfassembly that facilitate stem cell adhesion,mechanosensing,and differentiation both in vitro and in vivo,including the release of loaded molecules by destabilizing water bridges and hydrogen bonds between the Azo^(+)molecules and loaded molecules.Conversely,visible light induces trans-Azo^(+)formation that facilitates cation-πinteractions,thereby deflating self-assembly with“closely nanospaced”ligands that inhibits stem cell adhesion,mechanosensing,and differentiation.In stark contrast,when ligand nanospacing increases from 8.7 nm to 12.2 nm via the inflation of self-assembly,the surface area of“distantly nanospaced”ligands increases,thereby suppressing stem cell adhesion,mechanosensing,and differentiation.Long-term in vivo stability of self-assembly via real-time tracking and upconversion are verified.This tuning of ligand nanospacing can unravel dynamic ligand-cell interactions for stem cell-regulated tissue regeneration. 展开更多
关键词 Dynamic self-assembly Ligand nanospacing In vivo tracking Stem cell adhesion Stem cell fate
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Room-temperature sputtered electrocatalyst WSe2 nanomaterials for hydrogen evolution reaction 被引量:4
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作者 Jae Hyeon Nam Myeong Je Jang +4 位作者 Hye Yeon Jang Woojin Park Xiaolei Wang Sung Mook Choi Byungjin Cho 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第8期107-111,I0004,共6页
The low-temperature physical vapor deposition process of atomically thin two-dimensional transition metal dichalcogenide(2D TMD) has been gaining attention owing to the cost-effective production of diverse electrochem... The low-temperature physical vapor deposition process of atomically thin two-dimensional transition metal dichalcogenide(2D TMD) has been gaining attention owing to the cost-effective production of diverse electrochemical catalysts for hydrogen evolution reaction(HER) applications. We, herein, propose a simple route toward the cost-effective physical vapor deposition process of 2D WSe2 layered nanofilms as HER electrochemical catalysts using RF magnetron sputtering at room temperature(<27℃). By controlling the variable sputtering parameters, such as RF power and deposition time, the loading amount and electrochemical surface area(ECSA) of WSe2 films deposited on carbon paper can be carefully determined. The surface of the sputtered WSe2 films are partially oxidized, which may cause spherical-shaped particles. Regardless of the loading amount of WSe2, Tafel slopes of WSe2 electrodes in the HER test are narrowly distributed to be ~120–138 mV dec-1, which indicates the excellent reproducibility of intrinsic catalytic activity. By considering the trade-off between the loading amount and ECSA, the best HER performance is clearly observed in the 200 W-15 min sample with an overpotential of 220 mV at a current density of 10 mA cm-2. Such a simple sputtering method at low temperature can be easily expanded to other 2D TMD electrochemical catalysts, promising potentially practical electrocatalysts. 展开更多
关键词 Two dimensional nanomaterials Sputtering WSe2 nanofilm ELECTROCATALYST Hydrogen evolution reaction
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SYNCRIP controls miR-137 and striatal learning in animal models of methamphetamine abstinence 被引量:3
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作者 Baeksun Kim Sung Hyun Tag +12 位作者 Eunjoo Nam Suji Ham Sujin Ahn Juhwan Kim Doo-Wan Cho Sangjoon Lee Young-Su Yang Seung Eun Lee Yong Sik Kim Il-Joo Cho Kwang Pyo Kim Su-Cheol Han Heh-In Im 《Acta Pharmaceutica Sinica B》 SCIE CAS CSCD 2022年第8期3281-3297,共17页
Abstinence from prolonged psychostimulant use prompts stimulant withdrawal syndrome.Molecular adaptations within the dorsal striatum have been considered the main hallmark of stimulant abstinence. Here we explored str... Abstinence from prolonged psychostimulant use prompts stimulant withdrawal syndrome.Molecular adaptations within the dorsal striatum have been considered the main hallmark of stimulant abstinence. Here we explored striatal miRNA-target interaction and its impact on circulating miRNA marker as well as behavioral dysfunctions in methamphetamine(MA) abstinence. We conducted miRNA sequencing and profiling in the nonhuman primate model of MA abstinence, followed by miRNA qPCR,LC-MS/MS proteomics, immunoassays, and behavior tests in mice. In nonhuman primates, MA abstinence triggered a lasting upregulation of miR-137 in the dorsal striatum but a simultaneous downregulation of circulating miR-137. In mice, aberrant increase in striatal miR-137-dependent inhibition of SYNCRIP essentially mediated the MA abstinence-induced reduction of circulating miR-137. Pathway modeling through experimental deduction illustrated that the MA abstinence-mediated downregulation of circulating miR-137 was caused by reduction of SYNCRIP-dependent miRNA sorting into the exosomes in the dorsal striatum. Furthermore, diminished SYNCRIP in the dorsal striatum was necessary for MA abstinence-induced behavioral bias towards egocentric spatial learning. Taken together, our data revealed circulating miR-137 as a potential blood-based marker that could reflect MA abstinence-dependent changes in striatal miR-137/SYNCRIP axis, and striatal SYNCRIP as a potential therapeutic target for striatum-associated cognitive dysfunction by MA withdrawal syndrome. 展开更多
关键词 METHAMPHETAMINE ABSTINENCE WITHDRAWAL STRIATUM miR-137 SYNCRIP Biomarker Behavior
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Hybrid functional microfibers for textile electronics and biosensors
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作者 Bichitra Nanda Sahoo Byungwoo Choi +1 位作者 Jungmok Seo Taeyoon Lee 《Journal of Semiconductors》 EI CAS CSCD 2018年第1期117-134,共18页
Fibers are low-cost substrates that are abundantly used in our daily lives. This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions f... Fibers are low-cost substrates that are abundantly used in our daily lives. This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions for specific applications ranging from textile electronics to biomedical applications. By incorporating various nanomaterials such as carbon nanomaterials, metallic nanomaterials, and hydrogel-based biomaterials, the functions of fibers can be precisely engineered. This review also highlights the performance of the functional fibers and electronic materials incorporated with textiles and demonstrates their practical application in pressure/tensile sensors,chemical/biosensors, and drug delivery. Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructions with biomimetic properties have attracted substantial attention in the field of tissue engineering. We also discuss the current limitations of functional textile-based devices and their prospects for use in various future applications. 展开更多
关键词 textile electronics biosensors functional microfibers hybrid nanomaterials nanotechnology
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Computational screening of sodium solid electrolytes through unsupervised learning
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作者 Damdae Park Wonsuk Chung +3 位作者 Byoung Koun Min Ung Lee Seungho Yu Kyeongsu Kim 《npj Computational Materials》 CSCD 2024年第1期844-855,共12页
All-solid-state Na-ion batteries haveemerged as alternatives to all-solid-state Li-ion batteries owing to the global abundance of Na element.However,finding a commercially viable Na-ion solid-state electrolyte(SSE)rem... All-solid-state Na-ion batteries haveemerged as alternatives to all-solid-state Li-ion batteries owing to the global abundance of Na element.However,finding a commercially viable Na-ion solid-state electrolyte(SSE)remains challenging due to the relatively poor understanding of the structures effective for conduction compared to those for Li-ion SSE.In this study,we develop a screening framework based on an unsupervised machine learning technique to characterize Na-ion SSEs according to their lattice structures. 展开更多
关键词 SOLID ELEMENT ELECTROLYTE
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Brain physiome:A concept bridging in vitro 3D brain models and in silico models for predicting drug toxicity in the brain 被引量:4
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作者 Yoojin Seo Seokyoung Bang +7 位作者 Jeongtae Son Dongsup Kim Yong Jeong Pilnam Kim Jihun Yang Joon-Ho Eom Nakwon Choi Hong Nam Kim 《Bioactive Materials》 SCIE 2022年第7期135-148,共14页
In the last few decades,adverse reactions to pharmaceuticals have been evaluated using 2D in vitro models and animal models.However,with increasing computational power,and as the key drivers of cellular behavior have ... In the last few decades,adverse reactions to pharmaceuticals have been evaluated using 2D in vitro models and animal models.However,with increasing computational power,and as the key drivers of cellular behavior have been identified,in silico models have emerged.These models are time-efficient and cost-effective,but the prediction of adverse reactions to unknown drugs using these models requires relevant experimental input.Accordingly,the physiome concept has emerged to bridge experimental datasets with in silico models.The brain physiome describes the systemic interactions of its components,which are organized into a multilevel hierarchy.Because of the limitations in obtaining experimental data corresponding to each physiome component from 2D in vitro models and animal models,3D in vitro brain models,including brain organoids and brain-on-a-chip,have been developed.In this review,we present the concept of the brain physiome and its hierarchical organization,including cell-and tissue-level organizations.We also summarize recently developed 3D in vitro brain models and link them with the elements of the brain physiome as a guideline for dataset collection.The connection between in vitro 3D brain models and in silico modeling will lead to the establishment of cost-effective and time-efficient in silico models for the prediction of the safety of unknown drugs. 展开更多
关键词 Brain physiome In vitro 3D platform Brain organoid Brain-on-a-chip In silico model
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Exosome-guided direct reprogramming of tumor-associated macrophages from protumorigenic to antitumorigenic to fight cancer 被引量:3
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作者 Hyosuk Kim Hyun-Ju Park +12 位作者 Hyo Won Chang Ji Hyun Back Su Jin Lee Yae Eun Park Eun Hye Kim Yeonsun Hong Gijung Kwak Ick Chan Kwon Ji Eun Lee Yoon Se Lee Sang Yoon Kim Yoosoo Yang Sun Hwa Kim 《Bioactive Materials》 SCIE CSCD 2023年第7期527-540,共14页
Highly immunosuppressive tumor microenvironment containing various protumoral immune cells accelerates malignant transformation and treatment resistance.In particular,tumor-associated macrophages(TAMs),as the predomin... Highly immunosuppressive tumor microenvironment containing various protumoral immune cells accelerates malignant transformation and treatment resistance.In particular,tumor-associated macrophages(TAMs),as the predominant infiltrated immune cells in a tumor,play a pivotal role in regulating the immunosuppressive tumor microenvironment.As a potential therapeutic strategy to counteract TAMs,here we explore an exosome-guided in situ direct reprogramming of tumor-supportive M2-polarized TAMs into tumor-attacking M1-type macrophages.Exosomes derived from M1-type macrophages(M1-Exo)promote a phenotypic switch from anti-inflammatory M2-like TAMs toward pro-inflammatory M1-type macrophages with high conversion efficiency.Reprogrammed M1 macrophages possessing protein-expression profiles similar to those of classically activated M1 macrophages display significantly increased phagocytic function and robust cross-presentation ability,potentiating antitumor immunity surrounding the tumor.Strikingly,these M1-Exo also lead to the conversion of human patient-derived TAMs into M1-like macrophages that highly express MHC class II,offering the clinical potential of autologous and allogeneic exosome-guided direct TAM reprogramming for arming macrophages to join the fight against cancer. 展开更多
关键词 EXOSOME Cancer therapy Tumor microenvironment Tumor-associated macrophage Direct conversion
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A MEMS ultrasound stimulation system for modulation of neural circuits with high spatial resolution in vitro 被引量:4
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作者 Jungpyo Lee Kyungmin Ko +8 位作者 Hyogeun Shin Soo-Jin Oh CJustin Lee Namsun Chou Nakwon Choi Min Tack Oh Byung Chul Lee Seong Chan Jun Il-Joo Cho 《Microsystems & Nanoengineering》 EI CSCD 2019年第1期356-366,共11页
Neuromodulation by ultrasound has recently received attention due to its noninvasive stimulation capability for treating brain diseases.Although there have been several studies related to ultrasonic neuromodulation,th... Neuromodulation by ultrasound has recently received attention due to its noninvasive stimulation capability for treating brain diseases.Although there have been several studies related to ultrasonic neuromodulation,these studies have suffered from poor spatial resolution of the ultrasound and low repeatability with a fixed condition caused by conventional and commercialized ultrasound transducers.In addition,the underlying physics and mechanisms of ultrasonic neuromodulation are still unknown.To determine these mechanisms and accurately modulate neural circuits,researchers must have a precisely controllable ultrasound transducer to conduct experiments at the cellular level.Herein,we introduce a new MEMS ultrasound stimulation system for modulating neurons or brain slices with high spatial resolution.The piezoelectric micromachined ultrasonic transducers(pMUTs)with small membranes(submm membranes)generate enough power to stimulate neurons and enable precise modulation of neural circuits.We designed the ultrasound transducer as an array structure to enable localized modulation in the target region.In addition,we integrated a cell culture chamber with the system to make it compatible with conventional cell-based experiments,such as in vitro cell cultures and brain slices.In this work,we successfully demonstrated the functionality of the system by showing that the number of responding cells is proportional to the acoustic intensity of the applied ultrasound.We also demonstrated localized stimulation capability with high spatial resolution by conducting experiments in which cocultured cells responded only around a working transducer. 展开更多
关键词 NEURAL STIMULATION SYSTEM
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Inverse Problem of Flame Surface Properties of Wood using a Repulsive Particle Swarm Optimization Algorithm 被引量:1
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作者 Kyung-Beom Yoon Won-Hee Park 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第2期173-178,共6页
The convective heat transfer coefficient and surface emissivity before and after flame occurrence on a wood specimen surface and the flame heat flux were estimated using the repulsive particle swarm optimization algor... The convective heat transfer coefficient and surface emissivity before and after flame occurrence on a wood specimen surface and the flame heat flux were estimated using the repulsive particle swarm optimization algorithm and cone heater test results. The cone heater specified in the ISO 5660 standards was used, and six cone heater heat fluxes were tested. Preservative-treated Douglas fir 21 mm in thickness was used as the wood specimen in the tests. This study confirmed that the surface temperature of the specimen, which was calculated using the convective heat transfer coefficient, surface emissivity and flame heat flux on the wood specimen by a repulsive particle swarm optimization algorithm, was consistent with the measured temperature. Considering the measurement errors in the surface temperature of the specimen, the applicability of the optimization method considered in this study was evaluated. 展开更多
关键词 Repulsive particle swarm optimization Cone calorimeter Flame heat flux Flame surface properties
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Picomolar-sensitiveβ-amyloid fibril fluorophores by tailoring the hydrophobicity of biannulatedπ-elongated dioxaborine-dyes 被引量:1
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作者 Jusung An Peter Verwilst +5 位作者 Hira Aziz Jinwoo Shin Sungsu Lim Ilwha Kim Yun Kyung Kim Jong Seung Kim 《Bioactive Materials》 SCIE 2022年第7期239-248,共10页
The pathological origin of Alzheimer’s disease(AD)is still shrouded in mystery,despite intensive worldwide research efforts.The selective visualization ofβ-amyloid(Aβ),the most abundant proteinaceous deposit in AD,... The pathological origin of Alzheimer’s disease(AD)is still shrouded in mystery,despite intensive worldwide research efforts.The selective visualization ofβ-amyloid(Aβ),the most abundant proteinaceous deposit in AD,is pivotal to reveal AD pathology.To date,several small-molecule fluorophores for Aβspecies have been developed,with increasing binding affinities.In the current work,two organic small-molecule dioxaborine-derived fluorophores were rationally designed through tailoring the hydrophobicity with the aim to enhance the binding affinity for Aβ_(1-42) fibrils-while concurrently preventing poor aqueous solubility-via biannulate donor motifs in D-π-A dyes.An unprecedented sub-nanomolar affinity was found(K_(d)=0.62±0.33 nM)and applied to super-sensitive and red-emissive fluorescent staining of amyloid plaques in cortical brain tissue ex vivo.These fluorophores expand the dioxaborine-curcumin-based family of Aβ-sensitive fluorophores with a promising new imaging agent. 展开更多
关键词 Β-AMYLOID Small-molecular fluorescent probe Dioxaborine-dye Hydrophobicity tailoring Alzheimer’s disease
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Simultaneous creation of multiple vortex-antivortex pairs in momentum space in photonic lattices
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作者 Feng Li Sergei V.Koniakhin +6 位作者 Anton V.Nalitov Evgeniia Cherotchenko Dmitry D.Solnyshkov Guillaume Malpuech Min Xiao Yanpeng Zhang Zhaoyang Zhang 《Advanced Photonics》 SCIE EI CAS CSCD 2023年第6期92-100,共9页
Engineering of the orbital angular momentum(OAM)of light due to interaction with photonic lattices reveals rich physics and motivates potential applications.We report the experimental creation of regularly distributed... Engineering of the orbital angular momentum(OAM)of light due to interaction with photonic lattices reveals rich physics and motivates potential applications.We report the experimental creation of regularly distributed quantized vortex arrays in momentum space by probing the honeycomb and hexagonal photonic lattices with a single focused Gaussian beam.For the honeycomb lattice,the vortices are associated with Dirac points.However,we show that the resulting spatial patterns of vortices are strongly defined by the symmetry of the wave packet evolving in the photonic lattices and not by their topological properties.Our findings reveal the underlying physics by connecting the symmetry and OAM conversion and provide a simple and efficient method to create regularly distributed multiple vortices from unstructured light. 展开更多
关键词 VORTEX photonic lattice orbital angular momentum TOPOLOGY SYMMETRY
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Acute liver injury induces expression of FGF23 in hepatocytes via orphan nuclear receptor ERRγ signaling
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作者 Yoon Seok Jung Yong-Hoon Kim +7 位作者 Kamalakannan Radhakrishnan Jung-Ran Noh Jung Hyeon Choi Hyo-Jin Kim Jae-Ho Jeong Steven Dooley Chul-Ho Lee Hueng-Sik Choi 《Genes & Diseases》 SCIE CSCD 2023年第3期679-682,共4页
Fibroblast growth factor 23(FGF23)is an osteocyte-and osteoblast-derived hormone that primarily regulates phosphate and vitamin D metabolism.Circulatory FGF23 levels are abnormally increased in pathological conditions... Fibroblast growth factor 23(FGF23)is an osteocyte-and osteoblast-derived hormone that primarily regulates phosphate and vitamin D metabolism.Circulatory FGF23 levels are abnormally increased in pathological conditions like acute or chronic kidney injury,resulting in disease progression as well as increased rates of morbidity and mortality.^(1) However,FGF23 production in acute liver injury is not fully investigated.In this study. 展开更多
关键词 FGF23 ACUTE VITAMIN
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