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      • KCI등재

        Prevalence and Risk Factors of Cerebral Small Vessel Disease in a Chinese Population-Based Sample

        Fei Han,Fei-Fei Zhai,Quan Wang,Li-Xin Zhou,Jun Ni,Ming Yao,Ming-Li Li,Shu-Yang Zhang,Li-Ying Cui,Zheng-Yu Jin,Yi-Cheng Zhu 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.2

        Background and Purpose Epidemiological data of cerebral small vessel disease (CSVD) in the general population of China are lacking. We report on the prevalence of lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMBs) in a community-based sample in China and compare the results with those of other studies. Methods This was a cross-sectional analysis of the population-based Shunyi Study in China. A total of 1,211 stroke-free participants (mean age, 55.6±9.3 years; 37.4% men) with available 3 Tesla (3T) magnetic resonance images were included in this analysis. Demographic information and risk factor data were assessed. The overall and age-specific prevalence of lacunes, WMH, and CMBs was evaluated. Associations between cardiovascular risk factors and the presence of these lesions were analyzed by multiple logistic regression. Results Our study showed a prevalence of 14.5% for lacunes, 72.1% for periventricular hyperintensity (PVH), 65.4% for deep white matter hyperintensity (DWMH), and 10.6% for CMBs. When compared with other community-based samples, individuals in the same age group showed a higher burden of lacunes and a relatively lower prevalence of CMBs. Advanced age was independently associated with the prevalence of these CSVD markers, while the presence of hypertension increased the risk of lacunes, PVH/DWMH, and CMBs in deep or infratentorial locations. Conclusions A higher burden of lacunes but a relatively lower prevalence of CMBs was observed in this Chinese population. This notable result highlights the challenge of CSVD prevention in China. Chinese have a risk factor profile for CSVD similar to those in other populations.

      • Diffusion Mechanism of Lithium Ion through Basal Plane of Layered Graphene

        Yao, Fei,Gü,neş,, Fethullah,Ta, Huy Quang,Lee, Seung Mi,Chae, Seung Jin,Sheem, Kyeu Yoon,Cojocaru, Costel Sorin,Xie, Si Shen,Lee, Young Hee American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.20

        <P>Coexistence of both edge plane and basal plane in graphite often hinders the understanding of lithium ion diffusion mechanism. In this report, two types of graphene samples were prepared by chemical vapor deposition (CVD): (i) well-defined basal plane graphene grown on Cu foil and (ii) edge plane-enriched graphene layers grown on Ni film. Electrochemical performance of the graphene electrode can be split into two regimes depending on the number of graphene layers: (i) the corrosion-dominant regime and (ii) the lithiation-dominant regime. Li ion diffusion perpendicular to the basal plane of graphene is facilitated by defects, whereas diffusion parallel to the plane is limited by the steric hindrance that originates from aggregated Li ions adsorbed on the abundant defect sites. The critical layer thickness (<I>l</I><SUB>c</SUB>) to effectively prohibit substrate reaction using CVD-grown graphene layers was predicted to be ∼6 layers, independent of defect population. Our density functional theory calculations demonstrate that divacancies and higher order defects have reasonable diffusion barrier heights allowing lithium diffusion through the basal plane but neither monovacancies nor Stone-Wales defect.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2012/jacsat.2012.134.issue-20/ja301586m/production/images/medium/ja-2012-01586m_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja301586m'>ACS Electronic Supporting Info</A></P>

      • SCISCIESCOPUS

        Humidity-assisted selective reactivity between NO<sub>2</sub> and SO<sub>2</sub> gas on carbon nanotubes

        Yao, Fei,Duong, Dinh Loc,Lim, Seong Chu,Yang, Seung Bum,Hwang, Ha Ryong,Yu, Woo Jong,Lee, Il Ha,,neş,, Fethullah,Lee, Young Hee Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.12

        <P>In spite of the technical importance of detecting environmental SO<SUB><I>x</I></SUB> and NO<SUB><I>x</I></SUB> gases, a selective detection has not been realized because of their similar chemical properties. In this report, adsorption and desorption of SO<SUB>2</SUB> and NO<SUB>2</SUB> gas on carbon nanotubes are investigated in terms of different humidity levels at room temperature. A random-network single walled carbon nanotube (SWCNT) resistor is constructed by a dip-pen method using a SWCNT/dichloroethane (DCE) solution. In the case of SO<SUB>2</SUB> gas adsorption, the resistance increases at high humidity level (92%) and shows no obvious change at low humidity levels. On the other hand, in the case of NO<SUB>2</SUB> gas adsorption, the resistance always decreases independent of moisture levels. Our density functional theory (DFT) calculations show that this selective behavior originates from cooperative charge compensation between the SO<SUB>2</SUB>–<I>n</I>H<SUB>2</SUB>O complex and the p-type CNT resistor. The change of response time and recovery time with different moisture levels is further investigated. This humidity-assisted gas reaction provides a simple route to detect these two gases selectively.</P> <P>Graphic Abstract</P><P>Selective detection of SO<SUB>2</SUB> and NO<SUB>2</SUB> gas has been successfully realized on carbon nanotubes by introducing humidity in this study. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm03227a'> </P>

      • SCIESCOPUSKCI등재

        Low Specific On-resistance SOI LDMOS Device with P<sup>+</sup>P-top Layer in the Drift Region

        Yao, Jia-Fei,Guo, Yu-Feng,Xu, Guang-Ming,Hua, Ting-Ting,Lin, Hong,Xiao, Jian The Institute of Electronics and Information Engin 2014 Journal of semiconductor technology and science Vol.14 No.5

        In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

      • SCOPUSKCI등재

        The Synthesis of Eu<sup>3+</sup> Doped with TiO<sub>2</sub> Nano-Powder and Application as a Pesticide Sensor

        Yao, Fei,Sun, Yang,Tan, Chunlei,Wei, Song,Zhang, Xiaojuan,Hu, Xiaoyun,Fan, Jun Korean Chemical Society 2011 대한화학회지 Vol.55 No.6

        Using tetrabutyl titanate as precursor, $Eu^{3+}$ doped $TiO_2$ nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with $Eu^{3+}$ doped $TiO_2$ was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was quenched by chlorpyrifos and the quenching rate constant ($k_q$) was $1.24{\times}10^{11}\;L/mol{\cdot}s$ according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of $TiO_2$ nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (${\Delta}G_{et}$) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was proportional to chlorpyrifos concentration. The range of detection was $5.0{\times}10^{-10}-2.5{\times}10^{-7}mol/L$ and the election limit ($3{\sigma}$) was $3.2{\times}10^{-11}$ mol/L.

      • Carbon-Based Materials for Lithium-Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices.

        Yao, Fei,Pham, Duy Tho,Lee, Young Hee Wiley-VCH 2015 ChemSusChem Vol.8 No.14

        <P>A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent supply of mature energy-storage systems. As a result, lithium-ion batteries and electrochemical capacitors have lately attracted broad attention. Nevertheless, it is well known that both devices have their own drawbacks. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies of both devices to improve their electrochemical performance further. In this Review, electrochemical storage mechanisms based on carbon materials for both lithium-ion batteries and electrochemical capacitors are introduced. Non-faradic processes (electric double-layer capacitance) and faradic reactions (pseudocapacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolytes is briefly reviewed. Furthermore, impedance behavior based on Nyquist plots is discussed. We demonstrate the influence of cell conductivity, electrode/electrolyte interface, and ion diffusion on impedance performance. We illustrate that relaxation time, which is closely related to ion diffusion, can be extracted from Nyquist plots and compared between lithium-ion batteries and electrochemical capacitors. Finally, recent progress in the design of anodes for lithium-ion batteries, electrochemical capacitors, and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed.</P>

      • Component-based model for posttensioned steel connections against progressive collapse

        Yan Fei Zhu,Chang Hong Chen,Ying Huang,Zhaohui Huang,Yao Yao,Leon M. Keer 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.4

        A component-based method for the estimation of the posttensioned (PT) steel frame against progressive collapse is proposed and presented in the current paper. A mechanical model of PT steel connections is developed and benchmarked with experimental data of a PT beam-column substructure from literature. The developd mechanical models of four PT connections are able to capture the initial elastic stiffness, decompression load, and residual stiffness under lateral loading. Then, analysis of a reduced-scale three-storey two-bay PT steel frame is carried out with sufficient accuracy by incorporating the proposed joint model into the frame analysis. The proposed method is then applied to assessing progressive collapse of a one-storey two-bay PT frame under middle column removal scenario, and is verified against existing experimental and ANSYS finite element results. Three resistance mechanism for progressive collapse of the PT frame are evaluated, which consists of angle flexural mechanism, beam compression arching action and strand tensile catenary action. Finally, parameter analyses of the PT frames are conducted to investigate the effects of the connection details on the behavior and resistance of progressive collapse. The proposed model can be used to predict the quasi-static behavior of PT frames under monotonic vertical loading conditions with satisfactory accuracy.

      • KCI등재

        Dynamic increase factor for progressive collapse analysis of semi-rigid steel frames

        Yan Fei Zhu,Chang Hong Chen,Yao Yao,Leon M. Keer,Ying Huang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.2

        An empirical and efficient method is presented for calculating the dynamic increase factor to amplify the applied loads on the affected bays of a steel frame structure with semi-rigid connections. The nonlinear static alternate path analysis is used to evaluate the dynamic responses. First, the polynomial models of the extended end plate and the top and seat connection are modified, and the proposed polynomial model of the flush end plate connection shows good agreement as compared with experimental results. Next, a beam model with nonlinear spring elements and plastic hinges is utilized to incorporate the combined effect of connection flexibility and material nonlinearity. A new step-by-step analysis procedure is established to obtain quickly the dynamic increase factor based on a combination of the pushdown analysis and nonlinear dynamic analysis. Finally, the modified dynamic increase factor equation, defined as a function of the maximum ratio value of energy demand to energy capacity of an affected beam, is derived by curve fitting data points generated by the different analysis cases with different column removal scenarios and five types of semi-rigid connections.

      • KCI등재

        Efficiently targeted therapy of glioblastoma xenograft via multifunctional biomimetic nanodrugs

        Zhipeng Yao,Xiaochun Jiang,Hong Yao,Yafeng Wu,Fan Zhang,Cheng Wang,Chenxue Qi,Chenhui Zhao,Zeyu Wu,Min Qi,Jia Zhang,Xiaoxiang Cao,Zhichun Wang,Fei Wu,Chengyun Yao,Songqin Liu,Shizhang Ling,Hongping Xi 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

        Background: Glioblastoma multiforme (GBM) is a fatal malignant primary brain tumor in adults. The therapeutic efficacy of chemotherapeutic drugs is limited due to the blood-brain barrier (BBB), poor drug targeting, and short biological half-lives. Multifunctional biomimetic nanodrugs have great potential to overcome these limitations of chemotherapeutic drugs. Methods: We synthesized and characterized a biomimetic nanodrug CMS/PEG-DOX-M. The CMS/PEG-DOX-M effectively and rapidly released DOX in U87 MG cells. Cell proliferation and apoptosis assays were examined by the MTT and TUNEL assays. The penetration of nanodrugs through the BBB and anti-tumor efficacy were investigated in the orthotopic glioblastoma xenograft models. Results: We showed that CMS/PEG-DOX-M inhibited cell proliferation of U87 MG cells and effectively induced cell apoptosis of U87 MG cells. Intracranial antitumor experiments showed that free DOX hardly penetrated the BBB, but CMS/PEG-DOX-M effectively reached the orthotopic ntracranial tumor through the BBB and significantly inhibited tumor growth. Immunofluorescence staining of orthotopic tumor tissue sections confirmed that nanodrugs promoted apoptosis of tumor cells. This study developed a multimodal nanodrug treatment system with the enhanced abilities of tumor-targeting, BBB penetration, and cancer-specific accumulation of chemotherapeutic drugs by combining chemotherapy and photothermal therapy. It can be used as a flexible and effective GBM treatment system and it may also be used for the treatment of other central nervous systems (CNS) tumors and extracranial tumors.

      • SCIESCOPUSKCI등재

        Low Specific On-resistance SOI LDMOS Device with P<SUP>+</SUP>P-top Layer in the Drift Region

        Jia-Fei Yao,Yu-Feng Guo,Guang-Ming Xu,Ting-Ting Hua,Hong Lin,Jian Xiao 대한전자공학회 2014 Journal of semiconductor technology and science Vol.14 No.5

        In this paper, a novel low specific onresistance SOI LDMOS Device with P<SUP>+</SUP>P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped P<SUP>+</SUP> region which is connected to the P-top layer in the drift region. The P<SUP>+</SUP> region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel P<SUP>+</SUP>P-top device also present cost efficiency due to the fact that the P<SUP>+</SUP> region can be fabricated together with the P-type body contact region without any additional mask.

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