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Articles 1 - 24 of 24
Full-Text Articles in Engineering
Nonlocal Transistor Based On Pure Crossed Andreev Reflection In A Euo-Graphene/Superconductor Hybrid Structure, Yee Sin Ang, Lawrence Ang, C Zhang, Zhongshui Ma
Nonlocal Transistor Based On Pure Crossed Andreev Reflection In A Euo-Graphene/Superconductor Hybrid Structure, Yee Sin Ang, Lawrence Ang, C Zhang, Zhongshui Ma
Faculty of Engineering and Information Sciences - Papers: Part A
We study the interband transport in a superconducting device composed of graphene with EuO-induced exchange interaction. We show that pure crossed Andreev reflection can be generated exclusively without the parasitic local Andreev reflection and elastic cotunnelling over a wide range of bias and Fermi levels in an EuO-graphene/superconductor/EuO-graphene device. The pure nonlocal conductance exhibits rapid on-off switching and oscillatory behavior when the Fermi levels in the normal and the superconducting leads are varied. The oscillation reflects the quasiparticle propagation in the superconducting lead and can be used as a tool to probe the subgap quasiparticle mode in superconducting graphene, which …
Confined Sno2 Quantum-Dot Clusters In Graphene Sheets As High-Performance Anodes For Lithium-Ion Batteries, Chengling Zhu, Shenmin Zhu, Kai Zhang, Zeyu Hui, Hui Pan, Zhixin Chen, Yao Li, Di Zhang, Dawei Wang
Confined Sno2 Quantum-Dot Clusters In Graphene Sheets As High-Performance Anodes For Lithium-Ion Batteries, Chengling Zhu, Shenmin Zhu, Kai Zhang, Zeyu Hui, Hui Pan, Zhixin Chen, Yao Li, Di Zhang, Dawei Wang
Faculty of Engineering and Information Sciences - Papers: Part A
Construction of metal oxide nanoparticles as anodes is of special interest for next-generation lithium-ion batteries. The main challenge lies in their rapid capacity fading caused by the structural degradation and instability of solid-electrolyte interphase (SEI) layer during charge/discharge process. Herein, we address these problems by constructing a novel-structured SnO2-based anode. The novel structure consists of mesoporous clusters of SnO2 quantum dots (SnO2 QDs), which are wrapped with reduced graphene oxide (RGO) sheets. The mesopores inside the clusters provide enough room for the expansion and contraction of SnO2 QDs during charge/discharge process while the integral structure …
Encapsulation Of Fe3o4 Nanoparticles Into N, S Co-Doped Graphene Sheets With Greatly Enhanced Electrochemical Performance, Zunxian Yang, Kun Qian, Jun Lv, Wenhuan Yan, Jiahui Liu, Jingwei Ai, Yuxiang Zhang, Tailiang Guo, Xiongtu Zhou, Sheng Xu, Zaiping Guo
Encapsulation Of Fe3o4 Nanoparticles Into N, S Co-Doped Graphene Sheets With Greatly Enhanced Electrochemical Performance, Zunxian Yang, Kun Qian, Jun Lv, Wenhuan Yan, Jiahui Liu, Jingwei Ai, Yuxiang Zhang, Tailiang Guo, Xiongtu Zhou, Sheng Xu, Zaiping Guo
Faculty of Engineering and Information Sciences - Papers: Part A
Particular N, S co-doped graphene/Fe3O4 hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe3O4 nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe3O4 composite electrode exhibits a high initial reversible capacity …
Graphene/Pvdf Flat-Sheet Membrane For The Treatment Of Ro Brine From Coal Seam Gas Produced Water By Air Gap Membrane Distillation, Yun Chul Woo, Youngjin Kim, Wang-Geun Shim, Leonard D. Tijing, Minwei Yao, Long D. Nghiem, June-Seok Choi, Seung-Hyun Kim, Ho Kyong Shon
Graphene/Pvdf Flat-Sheet Membrane For The Treatment Of Ro Brine From Coal Seam Gas Produced Water By Air Gap Membrane Distillation, Yun Chul Woo, Youngjin Kim, Wang-Geun Shim, Leonard D. Tijing, Minwei Yao, Long D. Nghiem, June-Seok Choi, Seung-Hyun Kim, Ho Kyong Shon
Faculty of Engineering and Information Sciences - Papers: Part A
No abstract provided.
Klein Tunneling And Cone Transport In Aa-Stacked Bilayer Graphene, Matthew Sanderson, Yee Sin Ang, C Zhang
Klein Tunneling And Cone Transport In Aa-Stacked Bilayer Graphene, Matthew Sanderson, Yee Sin Ang, C Zhang
Yee Sin Ang
We investigate the quantum tunneling of electrons in an AA-stacked bilayer graphene (BLG) n-p junction and n-p-n junction. We show that Klein tunneling of an electron can occur in this system. The quasiparticles are not only chiral but are additionally described by a "cone index." Due to the orthogonality of states with different cone indexes, electron transport across a potential barrier must strictly conserve the cone index, and this leads to the protected cone transport which is unique in AA-stacked BLG. Together with the negative refraction of electrons, electrons residing in different cones can be spatially separated according to their …
Intraband Nonlinear Terahertz Waves Absorption Of Gapped Graphene, Asya Tawfiq, Yee Sin Ang, Chao Zhang
Intraband Nonlinear Terahertz Waves Absorption Of Gapped Graphene, Asya Tawfiq, Yee Sin Ang, Chao Zhang
Yee Sin Ang
The effect of bandgap opening on the intraband nonlinear optical response of graphene in terahertz frequency regime is theoretically investigated. The nonlinear optical response of gapped graphene is found to be sensitively influenced by the bandgap level and temperature. © 2012 IEEE.
Nonlinear Optical Response Of Graphene Superlattice In Terahertz Frequency Regime, Yee Sin Ang, Chao Zhang
Nonlinear Optical Response Of Graphene Superlattice In Terahertz Frequency Regime, Yee Sin Ang, Chao Zhang
Yee Sin Ang
We investigate the nonlinear optical response of a Kronig-Penney type graphene superlattice in which the Fermi velocity of the massless Dirac quasiparticle anisotropically depends on the direction of propagation. Such velocity anisotropy results in enhanced nonlinear optical response in terahertz frequency regime.
A Fe/Fe3o4/N-Carbon Composite With Hierarchical Porous Structure And In Situ Formed N-Doped Graphene-Like Layers For High-Performance Lithium Ion Batteries, Yao Li, Qing Meng, Shenmin Zhu, Zeng-Hui Sun, Hao Yang, Zhixin Chen, Chengling Zhu, Zaiping Guo, Di Zhang
A Fe/Fe3o4/N-Carbon Composite With Hierarchical Porous Structure And In Situ Formed N-Doped Graphene-Like Layers For High-Performance Lithium Ion Batteries, Yao Li, Qing Meng, Shenmin Zhu, Zeng-Hui Sun, Hao Yang, Zhixin Chen, Chengling Zhu, Zaiping Guo, Di Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
Fe/Fe3O4/N-carbon composite consisting of a porous carbon matrix containing a highly conductive N-doped graphene-like network and Fe/Fe3O4 nanoparticles was prepared. The porous carbon has a hierarchical structure which is inherited from rice husk and the N-doped graphene-like network formed in situ. When used as an anode material for lithium batteries, the composite delivered a reversible capacity of approximately 610 mA h g(-1) at a current density of 200 mA g(-1) even after 100 cycles, due to the synergism between the unique hierarchical porous structures, highly electrically conductive N-doped graphene- like networks and nanosized particles of Fe/Fe3O4. This work provides a …
Enhanced Tensile Properties Of Aluminium Matrix Composites Reinforced With Graphene Encapsulated Sic Nanoparticles, Alireza Fadavi Boostani, S Tahamtan, Zhengyi Jiang, Dongbin Wei, Siamak Yazdani, R Azari Khosroshahi, R Taherzadeh Mousavian, Jianzhong Xu, X M. Zhang, Dianyao Gong
Enhanced Tensile Properties Of Aluminium Matrix Composites Reinforced With Graphene Encapsulated Sic Nanoparticles, Alireza Fadavi Boostani, S Tahamtan, Zhengyi Jiang, Dongbin Wei, Siamak Yazdani, R Azari Khosroshahi, R Taherzadeh Mousavian, Jianzhong Xu, X M. Zhang, Dianyao Gong
Faculty of Engineering and Information Sciences - Papers: Part A
Due to a high propensity of nano-particles to agglomerate, making aluminium matrix composites with a uniform dispersion of the nano-particles using liquid routes is an exceptionally difficult task. In this study, an innovative approach was utilised to prevent agglomeration of nano-particle by encapsulating SiC nano-particles using graphene sheets during ball milling. Subsequently, the milled mixture was incorporated into A356 molten alloy using non-contact ultrasonic vibration method. Two different shapes for graphene sheets were characterised using HRTEM, including onion-like shells encapsulating SiC particles and disk-shaped graphene nanosheets. This resulted in 45% and 84% improvement in yield strength and tensile ductility, respectively. …
Defects Induced Ferromagnetism In Plasma-Enabled Graphene Nanopetals, Zengji Yue, Donghan Seo, Kostya Ostrikov, Xiaolin Wang
Defects Induced Ferromagnetism In Plasma-Enabled Graphene Nanopetals, Zengji Yue, Donghan Seo, Kostya Ostrikov, Xiaolin Wang
Faculty of Engineering and Information Sciences - Papers: Part A
Ferromagnetism in graphene is fascinating, but it is still a big challenge for practical applications due to the weak magnetization. In order to enhance the magnetization, here, we design plasma-enabled graphene nanopetals with ultra-long defective edges of up to 105 m/g, ultra-dense lattice vacancies, and hydrogen chemisorptions. The designed graphene nanopetals display robust ferromagnetism with large saturation magnetization of up to 2 emu/g at 5 K and 1.2 emu/g at room temperatures. This work identifies the plasma-enabled graphene nanopetals as a promising candidate for graphene-based magnetic devices. 2014 AIP Publishing LLC.
Coherent And Tunable Terahertz Radiation From Graphene Surface Plasmon Polaritons Excited By An Electron Beam, Shenggang Liu, Chao Zhang, Min Hu, Xiaoxing Chen, Ping Zhang, Sen Gong, Tao Zhao, Renbin Zhong
Coherent And Tunable Terahertz Radiation From Graphene Surface Plasmon Polaritons Excited By An Electron Beam, Shenggang Liu, Chao Zhang, Min Hu, Xiaoxing Chen, Ping Zhang, Sen Gong, Tao Zhao, Renbin Zhong
Faculty of Engineering and Information Sciences - Papers: Part A
Although surface plasmon polaritons (SPPs) resonance in graphene can be tuned in the terahertz regime, transforming such SPPs into coherent terahertz radiation has not been achieved. Here, we propose a graphene-based coherent terahertz radiation source with greatly enhanced intensity. The radiation works at room temperature, it is tunable and can cover the whole terahertz regime. The radiation intensity generated with this method is 400 times stronger than that from SPPs at a conventional dielectric or semiconducting surface and is comparable to that from the most advanced photonics source such as a quantum cascade laser. The physical mechanism for this strong …
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Shi Xue Dou
Electron-phonon coupling strength was studied in graphene-MgB2 composites to explore the possibilities for a higher superconducting transition temperature (Tc). For the first time in the experimental work on MgB2, the Raman active E2g mode was split into two parts: a softened mode corresponding to tensile strain and a hardened mode attributed to the carbon substitution effect. The tensile strain effect is suggested to improve Tc of graphene-MgB2 composites because it increases the electron-phonon coupling strength of MgB2.
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Faculty of Engineering and Information Sciences - Papers: Part A
Electron-phonon coupling strength was studied in graphene-MgB2 composites to explore the possibilities for a higher superconducting transition temperature (Tc). For the first time in the experimental work on MgB2, the Raman active E2g mode was split into two parts: a softened mode corresponding to tensile strain and a hardened mode attributed to the carbon substitution effect. The tensile strain effect is suggested to improve Tc of graphene-MgB2 composites because it increases the electron-phonon coupling strength of MgB2.
Rapid Synthesis Of Free-Standing Moo3/Graphene Films By The Microwave Hydrothermal Method As Cathode For Bendable Lithium Batteries, Lukman Noerochim, Jia-Zhao Wang, David Wexler, Zhong Chao, Hua-Kun Liu
Rapid Synthesis Of Free-Standing Moo3/Graphene Films By The Microwave Hydrothermal Method As Cathode For Bendable Lithium Batteries, Lukman Noerochim, Jia-Zhao Wang, David Wexler, Zhong Chao, Hua-Kun Liu
Faculty of Engineering and Information Sciences - Papers: Part A
Highly flexible, binder-free, MoO3 nanobelt/graphene film electrode is prepared by a two-step microwave hydrothermal method. Graphene is first prepared by an ultra-fast microwave hydrothermal method and then mixed with MoO3 solution to synthesize the MoO3 nanobelt/graphene composite, which exhibits the combination of stacked graphene sheets and uniform MoO3 nanobelts with widths of 200-500 nm and lengths of 5-10 μm. The charge-discharge measurements show that the as-synthesized MoO3/graphene hybrid materials demonstrate excellent rate capability, large capacity, and good cycling stability compared to the pure MoO3 film. An initial discharge capacity of 291 mAh g-1 can be obtained at 100 mA g-1, …
Enhanced Rate Performance Of Cobalt Oxide/Nitrogen Doped Graphene Composite For Lithium Ion Batteries, Dan Li, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Dianzeng Jia, Zaiping Guo
Enhanced Rate Performance Of Cobalt Oxide/Nitrogen Doped Graphene Composite For Lithium Ion Batteries, Dan Li, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Dianzeng Jia, Zaiping Guo
Faculty of Engineering and Information Sciences - Papers: Part A
Ultrafine Co3O4 nanocrystals homogeneously attached to nitrogen doped reduced graphene oxide (rGO) by the hydrothermal reaction method are demonstrated as anode materials for lithium ion batteries. Transmission electron microscope images revealed that the crystal size of Co3O4 in Co3O4/N-rGO and Co3O4/rGO is 5-10 nm, much smaller than that of bare Co3O4, indicating that the reduced graphene oxide sheets with Co3O4 nanocrystals attached could hinder the growth and aggregation of Co3O4 crystals during synthesis. The graphene sheets can also effectively buffer the volume change of Co3O4 upon lithium insertion/extraction, thus improving the cycling performance of the composite electrodes. The doped nitrogen …
In Situ One-Step Synthesis Of A 3d Nanostructured Germanium-Graphene Composite And Its Application In Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, David Wexler, Hua-Kun Liu
In Situ One-Step Synthesis Of A 3d Nanostructured Germanium-Graphene Composite And Its Application In Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, David Wexler, Hua-Kun Liu
Faculty of Engineering and Information Sciences - Papers: Part A
A germanium-graphene nanocomposite material with three-dimensional nanostructures has been synthesized by an efficient one-step, in situ, and aqueous-based method. The electrochemical properties of the germanium-graphene nanocomposite have been evaluated by galvanostatic discharge-charge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Results show that the germanium-graphene nanocomposite has a much more stable cycling performance than that of the pure germanium, with a capacity of about 832 mA h g-1 after 50 cycles. The rate capability is also improved significantly. The superior performance is attributed to the graphene content, which increases the material's conductivity, enlarges the specific surface area, delivers enough sites to …
Controlled Fabrication Of Si Nanoparticles On Graphene Sheets For Li-Ion Batteries, Shenmin Zhu, Chengling Zhu, Jun Ma, Qing Meng, Zaiping Guo, Ziyong Yu, Tao Lu, Yao Li, Di Zhang, Woon Ming Lau
Controlled Fabrication Of Si Nanoparticles On Graphene Sheets For Li-Ion Batteries, Shenmin Zhu, Chengling Zhu, Jun Ma, Qing Meng, Zaiping Guo, Ziyong Yu, Tao Lu, Yao Li, Di Zhang, Woon Ming Lau
Faculty of Engineering and Information Sciences - Papers: Part A
A new route is presented for the synthesis of Si nanoparticle/Graphene (Si-Gr) composite by a sonochemical method and then magnesiothermic reduction process. During the process, silica particles were firstly synthesized and deposited on the surface of graphene oxide (SiO2-GO) by ultrasonic waves, subsequent low-temperature magnesiothermic reduction transformed SiO 2 to Si nanoparticles in situ on graphene sheets. The phase of the obtained materials was influenced by the weight ratio of Mg to SiO 2-GO. With the optimized ratio of 1 : 1, we can get Si nanoparticles on Gr sheets, with the average particle size of Si around 30 nm. …
A Unique Sandwich-Structured C/Ge/Graphene Nanocomposite As An Anode Material For High Power Lithium Ion Batteries, Dan Li, Kuok H. Seng, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Zaiping Guo
A Unique Sandwich-Structured C/Ge/Graphene Nanocomposite As An Anode Material For High Power Lithium Ion Batteries, Dan Li, Kuok H. Seng, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Zaiping Guo
Faculty of Engineering and Information Sciences - Papers: Part A
A unique sandwich-structured C/Ge/graphene composite with germanium nanoparticles trapped between graphene sheets is prepared by a microwave-assisted solvothermal reaction followed by carbon coating and thermal reduction. The graphene sheets are found to be effective in hindering the growth and aggregation of GeO2 nanoparticles. More importantly, the graphene sheets, coupled with the carbon coating, can buffer the volume changes of germanium in electrochemical lithium reactions. The unique sandwich structure features a highly conductive network of carbon, which can improve both the conductivity and the structural stability of the electrode material, and exemplifies a promising strategy for the development of new high …
Graphene-Polymer Multilayer Heterostructure For Terahertz Metamaterials, Zaiquan Xu, Caiyun Chen, Steve Qing Yang Wu, Bing Wang, Jinghua Teng, Chao Zhang, Qiaoliang Bao
Graphene-Polymer Multilayer Heterostructure For Terahertz Metamaterials, Zaiquan Xu, Caiyun Chen, Steve Qing Yang Wu, Bing Wang, Jinghua Teng, Chao Zhang, Qiaoliang Bao
Faculty of Engineering and Information Sciences - Papers: Part A
The optical response and plasmon coupling between graphene sheets for graphene/polymer multilayer heterostructures with controlled separation were systematically investigated. Anomalous transmission of light was experimentally observed in mid-infrared range. The position of the broad passband in the transmission spectra was observed to red-shift with the increase of the number of layers.
Klein Tunneling And Cone Transport In Aa-Stacked Bilayer Graphene, Matthew Sanderson, Yee Sin Ang, C Zhang
Klein Tunneling And Cone Transport In Aa-Stacked Bilayer Graphene, Matthew Sanderson, Yee Sin Ang, C Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
We investigate the quantum tunneling of electrons in an AA-stacked bilayer graphene (BLG) n-p junction and n-p-n junction. We show that Klein tunneling of an electron can occur in this system. The quasiparticles are not only chiral but are additionally described by a "cone index." Due to the orthogonality of states with different cone indexes, electron transport across a potential barrier must strictly conserve the cone index, and this leads to the protected cone transport which is unique in AA-stacked BLG. Together with the negative refraction of electrons, electrons residing in different cones can be spatially separated according to their …
Synthesis Of Mn3o4-Encapsulated Graphene Sheet Nanocomposites Via A Facile, Fast Microwave Hydrothermal Method And Their Supercapacitive Behaviour, Li Li, Kuok Hau Seng, Zhixin Chen, Hua-Kun Liu, Ivan P. Nevirkovets, Zaiping Guo
Synthesis Of Mn3o4-Encapsulated Graphene Sheet Nanocomposites Via A Facile, Fast Microwave Hydrothermal Method And Their Supercapacitive Behaviour, Li Li, Kuok Hau Seng, Zhixin Chen, Hua-Kun Liu, Ivan P. Nevirkovets, Zaiping Guo
Faculty of Engineering and Information Sciences - Papers: Part A
Well-crystallized Mn3O4-anchored reduced graphene oxide (rGO) nanocomposites have been successfully synthesized via a facile, effective, energy-saving, and scalable microwave hydrothermal technique for potential application as supercapacitor material. Integrating these nanostructures resulted in a strong synergistic effect between the two materials, consequently leading to a hybrid composite with higher specific capacitance compared to the bare Mn3O4 nanoparticles. The results from different sorts of characterization indicate that the Mn3O4 particles were deposited and anchored on graphene sheets. The capacitance value of the rGO(31.6%)–Mn3O4 nanocomposite reached 153 F/g, much higher than that of the bare Mn3O4 (87 F/g) at a scan rate of …
Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang
Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
We theoretically investigate the nonlinear terahertz photon-mixing effect in graphene and topological insulator. We show that the nonlinear intraband optical absorption in both materials dominate over the linear response under a very moderate external electric field strength. The nonlinear response is thermally enhanced and the optical nonlinearity is well-preserved even in high temperature regime.
Nonlinear Optical Response Of Graphene Superlattice In Terahertz Frequency Regime, Yee Sin Ang, Chao Zhang
Nonlinear Optical Response Of Graphene Superlattice In Terahertz Frequency Regime, Yee Sin Ang, Chao Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
We investigate the nonlinear optical response of a Kronig-Penney type graphene superlattice in which the Fermi velocity of the massless Dirac quasiparticle anisotropically depends on the direction of propagation. Such velocity anisotropy results in enhanced nonlinear optical response in terahertz frequency regime.
Low Temperature Graphene Growth, Shailesh Kumar, N Mcevoy, T. Lutz, G. Keeley, Nicholas Whiteside, Werner Blau, G. Duesberg
Low Temperature Graphene Growth, Shailesh Kumar, N Mcevoy, T. Lutz, G. Keeley, Nicholas Whiteside, Werner Blau, G. Duesberg
Faculty of Engineering and Information Sciences - Papers: Part A
We demonstrate the growth of graphene films on nickel substrates by chemical vapour deposition using acetylene at temperatures as low as 750 degrees celsius, opening a viable route for its scalable production. Raman spectroscopy was used to confirm defect-free mono and multilayer graphene at and above this temperature, and of defective graphene at lower temperatures. Atomic force microscopy and scanning electron microscopy performed directly on the films give an indication of graphene flake size, morphology and also the topography on substrate. An unexpected dependence of graphene thickness on precursor dwell time is reported. This together with low temperature growth suggests …