检索结果-南通市图书馆

Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 687-697页

作者： Sun Hee KIM hyung jeong yang Kam Swee NG Department of Computer Science Chonnam National University

Missing values occur in bio-signal processing for various reasons,including technical problems or biological *** missing values are then either simply excluded or substituted with estimated values for further *** the missing signal values are estimated for electroencephalography (EEG) signals,an example where electrical signals arrive quickly and successively,rapid processing of high-speed data is required for immediate decision *** this study,we propose an incremental expectation maximization principal component analysis (iEMPCA) method that automatically estimates missing values from multivariable EEG time series data without requiring a whole and complete data *** proposed method solves the problem of a biased model,which inevitably results from simply removing incomplete data rather than estimating them,and thus reduces the loss of information by incorporating missing values in real *** using an incremental approach,the proposed method alsominimizes memory usage and processing time of continuously arriving *** results show that the proposed method assigns more accurate missing values than previous methods.

关键词： Electroencephalography (EEG) Missing value imputation Hidden pattern discovery Expectation maximization Principal component analysis

Boosting the catalytic activity toward oxygen reduction via a heterostructure of porous iron oxide-decorated 2D NiO/NG nanosheets

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第6期93卷 669-681,I0016页

作者： Kakali Maiti Matthew T.Curnan hyung Jun Kim Kyeounghak Kim jeong Woo Han Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbuk 37673Republic of Korea Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoul 08826Republic of Korea Department of Chemical Engineering Clean-Energy Research InstituteHanyang UniversitySeoul 04763Republic of Korea CSIR-Institute of Minerals and Materials Technology RRL CampusAcharya ViharBhubaneswarOdisha 751013India

As a noble metal substitute,two-dimensional(2D)hierarchical nano-frame structures have attracted great interest as candidate catalysts due to their remarkable advantages-high intrinsic activity,high electron mobility,and straightforward surface ***,they may replace Pt-based catalysts in oxygen reduction reaction(ORR)***,a simple method is developed to design hierarchical nano-frame structures assembled via 2D NiO and N-doped graphene(NG)*** procedure can yield nanostructures that satisfy the criteria correlated with improved electrocatalytic performance,such as large surface area,numerous undercoordinated atoms,and high defect ***,porous NG nanosheet architectures,featuring NiO nanosheets densely coordinated with accessible holey Fe_(2)O_(3) moieties,can enhance mesoporosity and balance *** improvements can facilitate charge transport and expose formerly inaccessible reaction sites,maximizing active site density *** functional theory(DFT)calculations reveal favored O_(2) adsorption and dissociation on Fe_(2)O_(3) hybrid structures when supported by 2D NiO and NG nanomaterials,given 2D materials donated charge to Fe_(2)O_(3) active *** systematic studies reveal that synergistic contributions are responsible for enriching the catalytic activity of Fe_(2)O_(3)@NiO/NG in alkaline media-encompassing internal voids and pores,unique hierarchical support structures,and concentrated N-dopant and bimetallic atomic ***,this work expands the toolbox for designing and synthesizing highly efficient 2D/2D shelled functional nanomaterials with transition metals,endeavoring to benefit energy conversion and related ORR applications.

关键词： N-doped graphene Holey Fe_(2)O_(3)nanocrystals NiO nanosheets High catalytic performance ORR

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

在线全文

学校读者我要写书评

暂无评论

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

Trifunctional robust electrocatalysts based on 3D Fe/N-doped carbon nanocubes encapsulating Co4N nanoparticles for efficient battery-powered water electrolyzers

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第6期6卷 124-139页

作者： hyung Wook Choi Hongdae Lee Jun Lu Seok Bin Kwon Dong In jeong Beum Jin Park Jiwon Kim Bong Kyun Kang Gun Jang Dae Ho Yoon Ho Seok Park SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Chemical Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Electronic Materials Devicesand Equipment EngineeringSoonchunhyang UniversityAsan CityChungnamRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwonRepublic of Korea

Herein,we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs,where Co_(4)N nanoparticles are encapsulated by Fe embedded in N-doped carbon nanocubes to synthesize hierarchically structured Co_(4)N@Fe/N-C for rechargeable zinc-air batteries and overall water-splitting *** confirmed by theoretical and experimental results,the high intrinsic oxygen reduction reaction,oxygen evolution reaction,and hydrogen evolution reaction activities of Co_(4)N@Fe/N-C were attributed to the formation of the heterointerface and the modulated local electronic ***,Co_(4)N@Fe/N-C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure,uniform distribution of Co_(4)N,and conductive encapsulation by Fe/***,the rechargeable zinc-air battery with Co_(4)N@Fe/N-C delivers a high specific capacity of 789.9 mAh g^(-1) and stable voltage profiles over 500 ***,the overall water electrolyzer with Co_(4)N@Fe/N-C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts,delivering a high Faradaic efficiency of 96.4%.Along with the great potential of the integrated water electrolyzer powered by a zinc-air battery for practical applications,therefore,the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

关键词： battery-powered electrolyzers hierarchical structure Prussian blue analog trifunctional electrocatalyst zinc-air battery

Role of marine natural products in the development of antiviral agents against SARS‑CoV‑2:potential and prospects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Marine Life Science & Technology 2024年第2期6卷 280-297页

作者： D.P.Nagahawatta N.M.Liyanage Thilina U.Jayawardena H.H.A.C.K.Jayawardhana Seong‑Hun jeong hyung‑Jun Kwon You‑Jin Jeon Department of Marine Life Sciences Jeju National UniversityJeju 690-756Republic of Korea Department of Chemistry Biochemistry and PhysicsUniversitédu QuébecàTrois-RivièresTrois-RivièresQC G8Z 4M3Canada Marine Science Institute Jeju National UniversityJeju 63333Republic of Korea Functional Biomaterial Research Center Korea Research Institute of Bioscience and BiotechnologyJeongeup-siRepublic of Korea

A novel coronavirus,known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has surfaced and caused global concern owing to its ***-CoV-2 is the causative agent of coronavirus disease 2019;however,it was only discovered at the end of the year and was considered a pandemic by the World Health ***,the develop-ment of novel potent inhibitors against SARS-CoV-2 and future outbreaks is urgently *** naturally occurring bioactive substances have been studied in the clinical setting for diverse *** intricate infection and replication mechanism of SARS-CoV-2 offers diverse therapeutic drug targets for developing antiviral medicines by employing natural products that are safer than synthetic *** natural products(MNPs)have received increased attention in the development of novel drugs owing to their high diversity and ***,this review article investigates the infection and replication mechanisms,including the function of the SARS-CoV-2 genome and ***,we highlighted anti-SARS-CoV-2 therapeutic intervention efforts utilizing MNPs and predicted SARS-CoV-2 inhibitor design.

关键词： SARS-CoV-2 Marine natural products Drug targets Inhibitors

Defect Engineering in Earth-Abundant Cu_(2)ZnSnSe_(4) Absorber Using Efficient Alkali Doping for Flexible and Tandem Solar Cell Applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2024年第2期7卷 249-256页

作者： Muhammad Rehan Ara Cho Inyoung jeong Kihwan Kim Asmat Ullah Jun-Sik Cho Joo hyung Park Yunae Jo Sung Jun Hong Seung Kyu Ahn SeJin Ahn Jae Ho Yun Jihye Gwak Donghyeop Shin Photovoltaics Research Department Korea Institute of Energy Research(KIER)152-Gajeong-roYuseong-guDaejeon 34129Korea Department of Renewable Energy Engineering University of Science and Technology(UST)217-Gajeong-roYuseong-guDaejeon 34113Korea Korea Institute of Energy Technology(KENTECH) 50772 Ujeong-roNaju Jeonnam 58217Korea

To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was ***,high-quality CZTSe films were grown at 480℃by a single co-evaporation,which is applicable to polyimide(PI)*** of the alkali-free substrate,Na and K alkali doping were systematically studied and optimized to precisely control the alkali distribution in *** bulk defect density was significantly reduced by suppression of deep acceptor states after the(NaF+KF)*** the low-temperature deposition with(NaF+KF)PDTs,the CZTSe device on glass yields the best efficiency of 8.1%with an improved Voc deficit of 646 *** developed deposition technologies have been applied to *** the first time,we report the highest efficiency of 6.92%for flexible CZTSe solar cells on ***,CZTSe devices were utilized as bottom cells to fabricate four-terminal CZTSe/perovskite tandem cells because of a low bandgap of CZTSe(~1.0 eV)so that the tandem cell yielded an efficiency of 20%.The obtained results show that CZTSe solar cells prepared by a low-temperature process with in-situ alkali doping can be utilized for flexible thin-film solar cells as well as tandem device applications.

关键词： alkali doping Earth-abundant Cu_(2)ZnSnSe_(4) flexible solar cells four-terminal tandem cells low-temperature process

Limitations of teleporting a qubit via a two-mode squeezed state

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2019年第5期7卷 I0001-I0007页

作者： SEOK hyung LIE HYUNSEOK jeong Center for Macroscopic Quantum Control Department of Physics and Astronomy Seoul National University

Recently, a teleportation scheme using a two-mode squeezed state to teleport a photonic qubit, so called a“hybrid” approach, has been suggested and experimentally demonstrated as a candidate to overcome the limitations of all-optical quantum information processing. We find, however, that there exists the upper bound of fidelity when teleporting a photonic qubit via a two-mode squeezed channel under a lossy *** increase of photon loss decreases this bound, and teleportation better than this limit is impossible even when the squeezing degree of the teleportation channel becomes infinity. Our result indicates that the hybrid scheme can be valid for fault-tolerant quantum computing only when the photon loss rate can be suppressed under a certain limit.

关键词： teleport a photonic qubit experimentally demonstrated photon loss decreases

Stone extraction balloon-guided repeat self-expanding metal stent placement

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2010年第24期16卷 3087-3090页

作者： hyung Hun Kim jeong Seop Moon Soo hyung Ryu Jung Hwan Lee You Sun Kim Division of Gastroenterology Department of Internal MedicineSeoul Paik Hospital Inje University College of Medicine

Self-expanding metal stent (SEMS) placement offers safe and effective palliation in patients with upper gastrointestinal obstruction due to a malignancy. Well described complications of SEMS placement include tumor growth, obstruction, and stent migration. SEMS occlusions are treated by SEMS redeployment, argon plasma coagulation application, balloon dilation, and surgical bypass. At our center, we usually place the second SEMS into the first SEMS if there is complete occlusion by the tumor. We discovered an unusual complication during SEMS redeployment. The guide-wire passed through the mesh of the first SEMS and caused the second SEMS to become entangled with the first SEMS. This led to the distortion and malfunction of the second SEMS, which worsened the gastric outlet obstruction. For lowering the risk of entanglement, we studied stone extraction balloon-guided repeat SEMS placement. This is the first report of a SEMS entangled by the mesh of the first SEMS and stone extraction balloon-guided repeat SEMS placement for lowering the risk of this complication.

关键词： Gastric outlet obstruction Self-expanding metal stent

Plasma Levels of Monocyte Chemotactic Protein 3 and Beta-Nerve Growth Factor Increase with Amnestic Mild Cognitive Impairment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2009年第2期6卷 143-147页

作者： Kang Soo Lee Ji hyung Chung Kyung Hye Lee Min-jeong Shin Byoung Hoon Oh Soo hyung Lee Chang hyung Hong Department of Psychiatry Yonsei University College of Medicine Institution of Behavioral Science in Medicine Yonsei University College of Medicine Yonsei University Research Institute of Science for Aging Yonsei University Department of Food and Nutrition College of Health Science Korea University Department of Family Medicine Seoul Medical Center Department of Psychiatry Ajou University School of Medicine Memory Impairment Center Ajou University Hospital Ajou University School of Medicine

A number of studies have investigated peripheral inflammatory indices, including plasma cytokines and related molecules according to subtypes of dementia, but not in mild cognitive impairment （MCI）. In this study, we used multiplex cytokine assay to assess the plasma levels of 22 cytokines in patients with MCI subtyped as amnestic and non-amnestic, according to cognitive features. When comparing the levels of plasma growth factors, chemokines and cytokines, plasma levels of monocyte chemotactic protein 3 （MCP-3）, and beta-nerve growth factor （β-NGF） in these two groups, they were found to be significantly higher in amnestic MCI patients than in non-amnestic MCI patients, after adjusting for age and gender. This suggests that plasma MCP-3 and β-NGF may be useful in differentiating subtypes of MCI.

关键词： mild cognitive impairment cytokine plasma inflammation biomarker

Leptin and peroxisome proliferator-activated receptor γ expression in colorectal adenoma

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第6期18卷 557-562页

作者： hyung Hun Kim You Sun Kim Yun Kyung Kang jeong Seop Moon Department of Internal Medicine Seoul Paik HospitalInje University College of MedicineSeoul 100-032South Korea Department of Pathology Seoul Paik HospitalInje University College of MedicineSeoul 100-032South Korea Hyung Hun Kim Department of Internal Medicine Kosin University College of MedicineBusan 602-702South Korea

AIM： To investigate the expressions of leptin and per- oxisome proliferator-activated receptor y （PPARG） in relation to body mass index （BMI）. METHODS： We evaluated leptin and PPARG expres- sion in 30 adenomas over 1 cm in size by immunohisto- chemical staining. In addition, clinicopathologic features including BMI were assessed. RESULTS： PPARG and leptin expression showed a strong positive correlation （P = 0.035）. The average BMI of the leptin-positive group was higher than that of the leptin-negative group （25.4 ＋ 3.4 kg/m2 vs 22.6 ＋ 2.4 kg/m2, P = 0.018）, and leptin expression was sig- nificantly correlated with high BMI （P = 0.024）. Leptinexpression was more frequently observed in intermedi- ate/high grade dysplasia than in low grade dysplasia （P = 0.030）. However, PPARG expression was not cor- related with BMI and grade of dysplasia. CONCLUSION： BMI has influenced on the leptin ex- pression of colorectal adenoma. The exact mechanism underlies the strong correlation between leptin and PPARG expression needs further study.

关键词： Leptin Peroxisome proliferator-activated re-ceptor y Obesity Body mass index Colorectal adenoma