http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Porous PVDF as effective sonic wave driven nanogenerators.
Cha, SeungNam,Kim, Seong Min,Kim, HyunJin,Ku, JiYeon,Sohn, Jung Inn,Park, Young Jun,Song, Byong Gwon,Jung, Myoung Hoon,Lee, Eun Kyung,Choi, Byoung Lyong,Park, Jong Jin,Wang, Zhong Lin,Kim, Jong Min,Ki American Chemical Society 2011 Nano letters Vol.11 No.12
<P>Piezomaterials are known to display enhanced energy conversion efficiency at nanoscale due to geometrical effect and improved mechanical properties. Although piezoelectric nanowires have been the most widely and dominantly researched structure for this application, there only exist a limited number of piezomaterials that can be easily manufactured into nanowires, thus, developing effective and reliable means of preparing nanostructures from a wide variety of piezomaterials is essential for the advancement of self-powered nanotechnology. In this study, we present nanoporous arrays of polyvinylidene fluoride (PVDF), fabricated by a lithography-free, template-assisted preparation method, as an effective alternative to nanowires for robust piezoelectric nanogenerators. We further demonstrate that our porous PVDF nanogenerators produce the rectified power density of 0.17 mW/cm3 with the piezoelectric potential and the piezoelectric current enhanced to be 5.2 times and 6 times those from bulk PVDF film nanogenerators under the same sonic-input.</P>
p‐Type Conduction Characteristics of Lithium‐Doped ZnO Nanowires
Lee, JunSeok,Cha, SeungNam,Kim, JongMin,Nam, HyeWon,Lee, SangHyo,Ko, WonBae,Wang, Kang L.,Park, JeaGun,Hong, JinPyo WILEY‐VCH Verlag 2011 Advanced Materials Vol.23 No.36
<P><B>p‐type ZnO nanowires (NWs) based on a simple hydrothermal technique with a lithium dopant</B> are demonstrated. It is demonstrated that Li substitution of Zn occurrs because of thermally induced migration due to post‐annealing in the presence of oxygen. The stable formation of p‐type ZnO:Li NWs is revealed using a NW field‐effect transistor and a simple n‐type ZnO thin film/p‐type annealed ZnO:Li NW homojunction diode.</P>
High Performance Electrocatalysts Based on Pt Nanoarchitecture for Fuel Cell Applications
Lee, Young-Woo,Cha, SeungNam,Park, Kyung-Won,Sohn, Jung Inn,Kim, Jong Min Hindawi Limited 2015 Journal of nanomaterials Vol.2015 No.-
<P>Fuel cells, converting chemical energy from fuels into electricity directly without the need for combustion, are promising energy conversion devices for their potential applications as environmentally friendly, energy efficient power sources. However, to take fuel cell technology forward towards commercialization, we need to achieve further improvements in electrocatalyst technology, which can play an extremely important role in essentially determining cost-effectiveness, performance, and durability. In particular, platinum- (Pt-) based electrocatalyst approaches have been extensively investigated and actively pursued to meet those demands as an ideal fuel cell catalyst due to their most outstanding activity for both cathode oxygen reduction reactions and anode fuel oxidation reactions. In this review, we will address important issues and recent progress in the development of Pt-based catalysts, their synthesis, and characterization. We will also review snapshots of research that are focused on essential dynamics aspects of electrocatalytic reactions, such as the shape effects on the catalytic activity of Pt-based nanostructures, the relationships between structural morphology of Pt-based nanostructures and electrochemical reactions on both cathode and anode electrodes, and the effects of composition and electronic structure of Pt-based catalysts on electrochemical reaction properties of fuel cells.</P>
Metal-Insulator Phase Transition in Quasi-One-Dimensional VO<sub>2</sub>Structures
Hong, Woong-Ki,Cha, SeungNam,Sohn, Jung Inn,Kim, Jong Min Hindawi Limited 2015 Journal of nanomaterials Vol.2015 No.-
<P>The metal-insulator transition (MIT) in strongly correlated oxides has attracted considerable attention from both theoretical and experimental researchers. Among the strongly correlated oxides, vanadium dioxide (VO2) has been extensively studied in the last decade because of a sharp, reversible change in its optical, electrical, and magnetic properties at approximately 341 K, which would be possible and promising to develop functional devices with advanced technology by utilizing MITs. However, taking the step towards successful commercialization requires the comprehensive understanding of MIT mechanisms, enabling us to manipulate the nature of transitions. In this regard, recently, quasi-one-dimensional (quasi-1D) VO2structures have been intensively investigated due to their attractive geometry and unique physical properties to observe new aspects of transitions compared with their bulk counterparts. Thus, in this review, we will address recent research progress in the development of various approaches for the modification of MITs in quasi-1D VO2structures. Furthermore, we will review recent studies on realizing novel functional devices based on quasi-1D VO2structures for a wide range of applications, such as a gas sensor, a flexible strain sensor, an electrical switch, a thermal memory, and a nonvolatile electrical memory with multiple resistance.</P>
Structural Analysis of ZnO Nanowires Synthesized by Using a Low-temperature Hydro-thermal Method
이상효,이준석,WonBae Ko,강태성,홍진표,SeungNam Cha 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10
Structural properties of vertically aligned ZnO nanowires (NWs) prepared with hydrothermal synthesis at various temperatures and different precursor concentrations are systematically described. The ZnO NWs are synthesized via an aqueous solution method with zinc nitrate (Zn(NO<SUB>3</SUB>)<SUB>2</SUB>∙6H<SUB>2</SUB>O) hexahydrate and hexamethylenetetramine (HMT) on ZnO seed layers. The growth speed and shape of ZnO NWs are particularly determined, depending on various mole concentrations. The structural analysis of the ZnO NWs is performed using X-ray diffraction, scanning electron microscopy and tunneling electron microscopy. Finally, the correlation of structural results with growth conditions, such as mole concentration and growth temperature of chemical precursors is discussed, based on Gibbs free energy.
Gunjakar, Jayavant L.,Inamdar, Akbar I.,Hou, Bo,Cha, SeungNam,Pawar, S. M.,Abu Talha, A. A.,Chavan, Harish S.,Kim, Jongmin,Cho, Sangeun,Lee, Seongwoo,Jo, Yongcheol,Kim, Hyungsang,Im, Hyunsik The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.19
<P>A mesoporous nanoplate network of two-dimensional (2D) layered nickel hydroxide Ni(OH)2 intercalated with polyoxovanadate anions (Ni(OH)2-POV) was built using a chemical solution deposition method. This approach will provide high flexibility for controlling the chemical composition and the pore structure of the resulting Ni(OH)2-POV nanohybrids. The layer-by-layer ordered growth of the Ni(OH)2-POV is demonstrated by powder X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The random growth of the intercalated Ni(OH)2-POV nanohybrids leads to the formation of an interconnected network morphology with a highly porous stacking structure whose porosity is controlled by changing the ratio of Ni(OH)2 and POV. The lateral size and thickness of the Ni(OH)2-POV nanoplates are ∼400 nm and from ∼5 nm to 7 nm, respectively. The obtained thin films are highly active electrochemical capacitor electrodes with a maximum specific capacity of 1440 F g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP>, and they withstand up to 2000 cycles with a capacity retention of 85%. The superior electrochemical performance of the Ni(OH)2-POV nanohybrids is attributed to the expanded mesoporous surface area and the intercalation of the POV anions. The experimental findings highlight the outstanding electrochemical functionality of the 2D Ni(OH)2-POV nanoplate network that will provide a facile route for the synthesis of low-dimensional hybrid nanomaterials for a highly active supercapacitor electrode.</P>
Lee, Sanghyo,Ko, Wonbae,Oh, Yujin,Lee, Jongsun,Baek, Gwangho,Lee, Younhee,Sohn, Junginn,Cha, Seungnam,Kim, Jongmin,Park, Jeagun,Hong, Jinpyo Elsevier 2015 Nano energy Vol.12 No.-
<P><B>Abstract</B></P> <P>Wearable energy harvesting devices are of increasing importance for the realization of flexible smart electronics, as the basic building blocks of power sources are able to convert the mechanical energy induced from body movement to electricity. Here, we report the electrical responses of a textile substrate-based triboelectric nanogenerator (T-TENG), including nanostructured surface configurations provided by Al nanoparticles and PDMS, in which no intricate fabrication process was performed or required. Along with analysis of the working principle and finite element simulation, the textile-based output power density of 33.6mW/cm<SUP>2</SUP> was obtained from the periodic mechanical stress of an adjustable bending machine, and this was used to activate commercially available light emitting diode (LED) bulbs. Additionally, we demonstrated the generation of sufficient energy from clothes attached to a commercial arm sleeve to power the LED devices from the activity of a human arm. Our practical cloth approach may contribute to a general framework for developing functional and self-powered wearable electronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Textle substrate was used to develope functional self-powered energy harvester. </LI> <LI> Electrical features of T-TENG was manipulated by various surface configurations. </LI> <LI> A self-powered clothes was demonstrated as one example of energy harvester. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Textile substrate-based triboelectric nanogenerator (T-TENG) including nanostructured surface configurations provided by Al nanoparticles and PDMS has been demonstrated for the generation of energy from clothes attached to a commercial arm sleeve in order to power the LED devices from the activity of a human arm.</P> <P>[DISPLAY OMISSION]</P>