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Charge transfer in graphene/polymer interfaces for CO2 detection

Nano Research 2018年第7期11卷 3529-3536页

作者： Myungwoo Son Yusin Pak Sang-Soo Chee Francis Malar Auxilia Kihyeun Kim Byung-Kee Lee Sungeun Lee Sun Kil Kang Chaedeok Lee Jeong Soo Lee Ki Kang Kim yun hee jang Byoung Hun Lee Gun-Young Jung Moon-Ho Ham School of Materials Science and Engineering Research Institute for Solar and Sustainable Energies Gwangju Institute of Science & Technology 723 Cheomdangwagi-ro Buk-gu Gwangju 61005 Republic of Korea Materials & Devices Advanced Research Institute LG Electronics Woomyeon R&D Campus 38 Baumoe-ro Seocho-gu Seoul 06763 Republic of Korea Department of Energy and Materials Engineering Dongguk University Seoul 04620 Republic of Korea Energy Systems Engineering Daegu Gyeongbuk Institute of Science & Technology 333 Technojungang-daero Hyeonpung-myeon Dalseong-gun Daegu 42988 Republic of Korea

Understanding charge transfer processes between graphene and functional materials is crucial from the perspectives of fundamental sciences and potential applications, including electronic devices, photonic devices, and sensors. In this study, we present the charge transfer behavior of graphene and amine-rich polyethyleneimine （PEI） upon CO2 exposure, which was significantly improved after introduction of hygroscopic polyethylene glycol （PEG） in humid air. By blending PEI and PEG, the number of protonated amine groups in PEI was remarkably increased in the presence of water molecules, leading to a strong electron doping effect on graphene. The presence of CO2 gas resulted in a large change in the resistance of PEI/PEG-co-functionalized graphene because of the dramatic reduction of said doping effect, reaching a maximum sensitivity of 32% at 5,000 ppm CO2 and an applied bias of 0.1 V in air with 60% relative humidity at room temperature. This charge transfer correlation will facilitate the development of portable graphene-based sensors for real-time gas detection and the extension of the applications of graphene-based electronic and photonic devices.

关键词： graphene polyethyleneimine (PEI) polyethylene glycol carbon dioxide charge transfer

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Health risks of pest control and disinfection workers after the COVID-19 outbreak in South Korea

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Journal of Environmental Sciences 2024年第5期139卷 350-363页

作者： yun-hee Choi Da-An Huh Lita Kim Sang ji Lee Kyong Whan Moon Department of Health and Safety Convergence Science Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841South Korea BK21 FOUR R&E Center for Learning Health System Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841South Korea Institute of Sciences Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841South Korea Department of Health and Environmental Science Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841South Korea

The exposure patterns of pest control and disinfection workers have changed after the coronavirus disease 2019(COVID-19)outbreak,but the health risks of chemical exposure have not been *** identified these workers’chemical exposure patterns and risks before and after the COVID-19 *** used data conducted between 2018(pre-pandemic)and 2021(post-pandemic)from three-year cross-sectional surveys on pest control and disinfection *** and dermal exposure concentrations were estimated using equations based on a biocidal product risk assessment model from the Korean National Institute of Environmental *** non-carcinogenic and carcinogenic risks of chemicals were calculated using the United States Environmental Protection Agency risk assessment *** found that the annual work frequency(50^(th)percentile)of foggers using disinfectants increased the most among all the work types,from 140 uses/year to 176 uses/year after the COVID-19 ***,all chemicals’non-carcinogenic and carcinogenic risks increased regardless of exposure *** the worst scenario(95^(th)percentile),the margin of exposure for citric acid,benzethonium chloride,benzyl-C12-16-alkyldimethyl chlorides,and sodium chlorite of inhalation exposure,and isopropyl alcohol and benzyl-C12-16-alkyldimethyl chlorides of dermal exposure were acceptable(>100)before the COVID-19outbreak but became unacceptable(10^(-6))before and after the COVID-19 outbreak but comparatively high after the COVID-19 ***,significantly more workers experienced health symptoms after the COVID-19outbreak(p<0.05),with the most common being muscle lethargy(31%),skin/face stinging(28.7%),and breath shortness/neck pain(24.1%).

关键词： Biocide Disinfection Health risk assessment Occupational exposure Pest control

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Random pinhole attenuator for high-power laser beams

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High Power Laser Science and Engineering 2024年第3期12卷 116-121页

作者： Seong Cheol Park Hyeok yun Jin Woo Yoon Seong Ku Lee Jae hee Sung Il Woo Choi Chang hee Nam Kyung Taec Kim Department of Physics and Photon Science Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea Center for Relativistic Laser Science Institute for Basic ScienceGwangjuRepublic of Korea Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea

The intensity attenuation of a high-power laser is a frequent task in the measurements of optical *** intensity can be attenuated by inserting an optical element,such as a partial reflector,polarizer or absorption *** devices are,however,not always easily applicable,especially in the case of ultra-high-power lasers,because they can alter the characteristics of a laser beam or become easily *** this study,we demonstrated that the intensity of a laser beam could be effectively attenuated using a random pinhole attenuator(RPA),a device with randomly distributed pinholes,without changing the beam *** this device,a multi-PW laser beam was successfully attenuated and the focused beam profile was measured without any alterations of its *** addition,it was confirmed that the temporal profile of a laser pulse,including the spectral phase,was ***,the RPA possesses significant potential for a wide range of applications.

关键词： high-power laser intensity attenuation laser diagnostics

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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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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon yun Boseok Seong Junseok Kim Sun hee Choi Ho-Il Ji Sihyuk Choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

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.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

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Practical operating flexibility of a bifunctional freestanding membrane for efficient anion exchange membrane water electrolysis across all current ranges

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Carbon Energy 2024年第9期6卷 306-324页

作者： Hong-Jin Son Jeemin Hwang Min Young Choi Seung hee Park Jae Hyuk jang Byungchan Han Sung Hoon Ahn Department of Bio-Chemical Engineering Chosun UniversityGwangjuRepublic of Korea Fuel Cell Research and Demonstration Center Hydrogen Energy Research DivisionKorea Institute of Energy Research(KIER)Buan-gunJeollabuk-doRepublic of Korea Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoulRepublic of Korea Center for Research Equipment Korea Basic Science InstituteDaejeonRepublic of Korea

This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic ***,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is *** method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss *** evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis *** technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current *** symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient *** results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology.

关键词： AEM water electrolysis fibrous membrane iR correction free operational stability symmetric configuration

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Ionizing terahertz waves with 260 MV/cm from scalable optical rectification

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Light(Science & Applications) 2024年第6期13卷 1075-1087页

作者： Hyeongmun Kim Chul Kang Dogeun jang Yulan Roh Sang Hwa Lee Joong Wook Lee Jae hee Sung Seong Ku Lee Ki-Yong Kim Advanced Photonics Research Institute GISTGwangju61005Korea Department of Physics and Optoelectronics Convergence Research Center Chonnam National UniversityGwangju61186Korea Pohang Accelerator Laboratory POSTECHPohang37673Korea Center for Relativistic Laser Science Institute for Basic ScienceGwangju61005Korea Institute for Research in Electronics and Applied Physics Department of PhysicsUniversity of MarylandCollege ParkMaryland20742USA

Terahertz(THz)waves,known as non-ionizing radiation owing to their low photon energies,can actually ionize atoms and molecules when a sufficiently large number of THz photons are concentrated in time and ***,we demonstrate the generation of ionizing,multicycle,15-THz waves emitted from large-area lithium niobate crystals via phase-matched optical rectification of 150-terawatt laser pulses.A complete characterization of the generated THz waves in energy,pulse duration,and focal spot size shows that the field strength can reach up to 260 megavolts per *** particular,a single-shot THz interferometer is employed to measure the THz pulse duration and spectrum with complementary numerical *** intense THz pulses are irradiated onto various solid targets to demonstrate THz-induced tunneling ionization and plasma *** study also discusses the potential of nonperturbative THz-driven ionization in gases,which will open up new opportunities,including nonlinear and relativistic THz physics in plasma.

关键词： optical interferometer matched

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ELK3-ID4 axis governs the metastatic features of triple negative breast cancer

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Oncology Research 2024年第1期32卷 127-138页

作者： JIN-HO CHOI JOO DONG PARK SEUNG hee CHOI EUN-SU KO HYE JUNG jang KyunG-SOON PARK Department of Biomedical Science CHA UniversitySeongnamKorea

Purpose:Cancer cell metastasis is a multistep process,and the mechanism underlying extravasation remains ***3 is a transcription factor that plays a crucial role in regulating various cellular processes,including cancer *** on the finding that ELK3 promotes the metastasis of triple-negative breast cancer(TNBC),we investigated whether ELK3 regulates the extravasation of TNBC by forming the ELK3-ID4 ***4 functions as a transcriptional regulator that interacts with other transcription factors,inhibiting their activity and subsequently influencing various biological processes associated with cell differentiation,survival,growth,and ***:We assessed the correlation between the expression of ELK3 and that of ID4 in TNBCs using bioinformatics analyses,QRT-PCR,western blot analysis,luciferase reporter assays,and chromatin ***,adhesion,invasion,and lung metastasis assays were employed to determine whether the ELK3-ID4 axis regulates the metastatic features of ***:We found that ELK3 binds directly to a binding motif close to the ID4 promoter to repress promoter *** expression of E-cadherin in TNBC was regulated by the ELK3-ID4 *** vitro and in vivo analyses showed that inhibiting ID4 expression in ELK3-knockdown MDA-MB-231(ELK3KD)cells restored the ability to extravasate and ***:The results indicate that the ELK3 regulates ID4 promoter activity,and that the ELK3-ID4 axis regulates the metastatic characteristics of TNBC ***,the data suggest that the ELK3-ID4 axis regulates metastasis of TNBCs by modulating expression of E-cadherin.

关键词： E-cadherin Extravasation Colonization

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Unravelling the role of the combined effect of metallic charge transfer channel and SiO_(x) overlayer in the Zr/Si-Fe_(2)O_(3):Au:SiO_(x) nanorod arrays to boost photoelectrochemical water splitting

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Journal of Energy Chemistry 2024年第3期90卷 370-379,I0009页

作者： Tae Sik Koh Periyasamy Anushkkaran Love Kumar Dhandole Mahadeo A.Mahadik Weon-Sik Chae Hyun Hwi Lee Sun hee Choi Jum Suk jang Division of Biotechnology SafetyEnvironment and Life Science InstituteCollege of Environmental and Bioresource SciencesJeonbuk National UniversityIksan 54896Republic of Korea Department of Integrative Environmental Biotechnology College of Environmental and Bioresource SciencesJeonbuk National UniversityIksan 54596Republic of Korea Extreme Materials Research Center Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Daegu Center Korea Basic Science InstituteDaegu 41566Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

Hematite(α-Fe_(2)O_(3)) based photoanodes have been extensively studied due to various intriguing features that make them viable candidates for a photoelectrochemical(PEC) water splitting ***,we propose a Zr-doped Fe_(2)O_(3) photoanode decorated with facilely spin-coated Au nanoparticles(NPs) and microwave-assisted attached Si co-doping in conjunction with a SiO_(x) overlayer that displayed a remarkable photocurrent density of 2.01 mA/cm^(2) at 1.23 V *** kinetic dynamics at the photoelectrode/-electrolyte interface was examined by employing systematic electrochemical *** Au NPs played a dual role in increasing PEC water ***,the Schottky interface that was formed between Au NPs and Zr-Fe_(2)O_(3) lectrode ensured the prevention of electron flow from the photoanode to the metal,increasing the number of available charges as well as suppressing surface charge ***,Au extracted photoholes from the bulk of the Zr-Fe_(2)O_(3) and transported them to the outer SiO_(x) overlayer,while the SiO_(x) overlayer efficiently collected the photoholes and promoted the hole injection into the ***,Si co-doping enhanced bulk conductivity by reducing bulk charge transfer resistance and improving charge carrier *** study outlines a technique to design a metallic charge transfer path with an overlayer for solar energy conversion.

关键词： Hematite Microwave attachment Au nanoparticles SiO_(x) overlayer Water splitting

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Unification of Gravitational and Strong Interaction Fields Using Partial Gauge Symmetry

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Journal of High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 515-533页

作者： Young Hwan yun Kiho jang Zero Theoretical Physics Lab Seoul Republic of Korea

We propose the new field potential by maintaining both the symmetry of the scalar gauge and the conservation law keeping N?ether’s theorem, while disregarding the symmetry of the vector gauge. The new potential forms like the well-type potential where a particle behaves almost freely but is very hard to escape without external energy, which can be interpreted as local confinement and asymptotic freedom. By assuming a 2-dimensional metric tensor in 4-dimensional space-time, we suggest the existence of 3 kinds of particles that resemble QCD with 3 color charges. We also show that the mass term exists but comes to zero and derive the charge and spin values. We can regard the particle with this new potential as a gluon, and the interaction in this well-type potential as a strong interaction for the properties of mass, charge, spin, and its behavior. We suggest the eight-fold way with this new particle, which is similar to the existing method based on SU (3) symmetry. Even though the strong interaction has been analyzed in the standard model and string theory, we build a new consistent model based on the theory of relativity including Riemann geometry, and show the unification of gravitational and strong interactional field.

关键词： Strong Interaction Gauge Symmetry Relativity QCD Confinement Asymptotic Freedom

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Defining and tracing subtypes of patient-derived xenograft models in pancreatic ductal adenocarcinoma

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Cancer Communications 2024年第8期44卷 915-920页

作者： Sangyeop Hyun Youngmin Han Jae yun Moon Young-Ah Suh Won-Gun yun Wooil Kwon Jong-Eun Lee Daeun Kim Ja-Lok Ku Jin-Young jang Daechan Park Department of Molecular Science and Technology Ajou UniversitySuwonRepublic of Korea Department of Surgery and Cancer Research Institute Seoul National University College of MedicineSeoulRepublic of Korea Molecular Science and Technology Research Center Ajou UniversitySuwonRepublic of Korea DNA Link Inc. SeoulRepublic of Korea Korean Cell Line Bank Laboratory of Cell BiologyCancer Research InstituteSeoul National University College of MedicineSeoulRepublic of Korea

Patient-derived xenograft(PDX)models have been used to explore therapeutic opportunities for pancreatic ductal adenocarcinoma(PDAC)[1].Although original tumor characteristics are altered by cancer-stromal interactions... 详细信息

关键词： adenocarcinoma ductal xenograft

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