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Full-Text Articles in Engineering
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Shi Xue Dou
Flexible silicon/single-walled carbon nanotube (Si/SWCNT) composite paper was prepared using the pulsed laser deposition (PLD) method to deposit Si onto SWCNT paper. In the composite, Si mainly shows nanoworm-like morphology. Increasing deposition time results in an increased amount of Si microspheres. Electrochemical measurements show that the capacity of the composite paper is improved by the presence of Si. The Si/SWCNT composite with only 2.2% Si shows a capacity of 163 mA h g−1 at a current density of 25 mA g−1 up to 50 cycles, which is more than 60% improvement of the capacity of pristine CNT paper. The Si …
Nanocoating Of Particles For Optimal Doping And Universal Enhancement Of Current-Carrying Ability In "Organic" Mgb2-Xcx Superconductors, Olga V. Shcherbakova, Alexey V. Pan, S X. Dou, Rashmi Nigam, David Wexler
Nanocoating Of Particles For Optimal Doping And Universal Enhancement Of Current-Carrying Ability In "Organic" Mgb2-Xcx Superconductors, Olga V. Shcherbakova, Alexey V. Pan, S X. Dou, Rashmi Nigam, David Wexler
Shi Xue Dou
The universal approach of liquid mixing has been found to produce “organic” MgB2−xCx superconductors with structural and supercurrent-carrying properties unattainable by other techniques. We show by transmission electron microscopy combined with energy dispersive spectroscopy that these unique properties are enabled through coating of boron particles with a nanolayer of carbon. The subsequent reaction between carbon-encapsulated boron and magnesium results in enhanced carbon content x in the crystal lattice, as determined by x-ray diffraction pattern analysis. Among various carbon-containing compounds investigated, polycarbosilane has been found to be the optimal dopant for MgB2 superconductor, producing the largest critical current density due to …
Increased Superconductivity For Cnt Doped Mgb2 Sintered In 5t Pulsed Magnetic Field, Wenxian Li, Ying Li, Rong Hua Chen, Rong Zeng, Lin Lu, Yun Zhang, Michael Tomsic, Matthew Rindfleisch, S. X. Dou
Increased Superconductivity For Cnt Doped Mgb2 Sintered In 5t Pulsed Magnetic Field, Wenxian Li, Ying Li, Rong Hua Chen, Rong Zeng, Lin Lu, Yun Zhang, Michael Tomsic, Matthew Rindfleisch, S. X. Dou
Shi Xue Dou
The superconductivity of carbon nanotube (CNT) doped MgB2 sintered in pulsed magnetic field (PMF) was investigated with Raman scattering measurements and Raman spectral fit analysis. Although the carbon (C) substitution for the boron (B) is increased for the sample sintered in PMF, its superconductivity is advanced comparing with the sample sintered without PMF. The improved critical transition temperature, Tc, is attributed to the strengthening of the electron-phonon coupling (EPC) in MgB2, as reflected by the broadened E 2g mode in the Raman spectra, because the carbon atoms are homogeneously distributed in the boron planes.
Chemical Modification Of Precursor Solution For Long Length Ybco Coated Conductor Fabrication, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Gye-Won Hong, Hee-Gyoun Lee, Jin-Heung Kim, Hyungsik Chung, X. L. Wang, S. X. Dou
Chemical Modification Of Precursor Solution For Long Length Ybco Coated Conductor Fabrication, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Gye-Won Hong, Hee-Gyoun Lee, Jin-Heung Kim, Hyungsik Chung, X. L. Wang, S. X. Dou
Shi Xue Dou
Long length MOD processing of YBCO conductor requires high performance precursor solution without degradation during the process. In this study, effect of chemical modification of precursor solution on MOD processing was investigated to meet the requirement. Highly stable YBCO precursor solution was synthesized with PVP (polyvinylpyrrolidone) and crack-free thick precursor film was successfully fabricated. However, annealed YBCO film shows porous microstructures originated from large HF gas generation from thick films and residual carbon from additives. Reduction of fluorine content is required to densify microstructures. In order to reduce fluorine content, F-free Cu-precursor solution was synthesized. YBCO film with Jc = …
Vortex Dynamics For Low- Type-Ii Superconductors, X B Xu, H Fangohr, Z H Wang, M Gu, S.L. Liu, Dongqi Shi, S. X. Dou
Vortex Dynamics For Low- Type-Ii Superconductors, X B Xu, H Fangohr, Z H Wang, M Gu, S.L. Liu, Dongqi Shi, S. X. Dou
Shi Xue Dou
Based on a model appropriate for “marginally type-II” superconducting system, we study the dynamics of vortices with competing interactions by Langevin dynamics simulation. In addition to pinned states and plastic flow, we find that the moving vortex system forms ordered bubble configurations and stripe structures, depending on pinning strength and driving force. The vortex system exhibits a marked hysteresis in its velocity-force characteristic, which results from a dynamical stripe reordering due to intervortex attraction.
Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou
Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou
Shi Xue Dou
MOD solutions for YBCO coated conductors were synthesized with fluorine-free Y & Cu precursor. The fluorine content in the precursor solution was significantly reduced and a fast calcination profile was realized. A crack-free & thick precursor film was successfully obtained just after less than 2 hours of calcination in wet O2 atmosphere. Optimization of the precursor solution with Sm addition enables further improvement of thickness and uniformity of precursor films. The calcinated precursor film was successfully converted to dense and uniform YBCO film after annealing in wet Ar/O2 atmosphere. The measured critical current value was about 273 A/cm-w (Jc ~ …
A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou
A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou
Shi Xue Dou
Co3O4 has shown acceptable electrochemical properties as the anode material of Li secondary batteries. In detail, its capacity reached about 700 mAh/g, twice as high as graphite, and 93.4% of initial capacity was retained after 100 cycles. EIS (electrochemical impedance spectroscopy) analyses revealed that after the 1st cycle, the insertion or extraction of Li ions in Co3O4 can occur homogeneously and reversibly (randless-like behavior, homogeneous mixture: Co + Li2O (in the state of Li insertion), Co3O4 (in the state of Li extraction)). In fact, the coulombic efficiency of Co3O4 was almost 100% except for the 1st cycle. According to P. …
Dependence Of Magnetoelectric Properties On Sintering Temperature For Nano-Sic-Doped Mgb2/Fe Wires Made By Combined In Situ/Ex Situ Process, Wenxian Li, Rong Zeng, Jiazhao Wang, Y Li, S. X. Dou
Dependence Of Magnetoelectric Properties On Sintering Temperature For Nano-Sic-Doped Mgb2/Fe Wires Made By Combined In Situ/Ex Situ Process, Wenxian Li, Rong Zeng, Jiazhao Wang, Y Li, S. X. Dou
Shi Xue Dou
Very fine nano-SiC particles (nm) were doped into a MgB2 superconductor. The influence of self-field supercurrent on the high-field performance of the nano-SiC-doped MgB2/Fe wires is discussed based on comparison of the critical current densities of the in situ processed nano-SiCdoped MgB2 wires and those of the nano-SiC-doped MgB2/Fe wires processed by the combination of in situ/ex situ methods.
Chemical Solution Deposition Of Lamno3 Buffer Layers For Coated Conductors, Xuebin Zhu, Hechang Lei, Dongqi Shi, Li Zhang, Lin Wang, Yuping Sun, Wenhai Song, S. X. Dou, Jian Yang, Hongwei Gu
Chemical Solution Deposition Of Lamno3 Buffer Layers For Coated Conductors, Xuebin Zhu, Hechang Lei, Dongqi Shi, Li Zhang, Lin Wang, Yuping Sun, Wenhai Song, S. X. Dou, Jian Yang, Hongwei Gu
Shi Xue Dou
Chemical solution deposition (CSD) is used to prepare LaMnO3 (LMO) buffer layers on different substrates. The results show that biaxially oriented LMO films can be successfully prepared on single-crystal SrTiO3 (STO) and STO buffered single-crystal LaAlO3 substrates when humid 4%H-2-N-2 annealing atmosphere is used. The orientation of LMO-Ni is (110)-oriented even when the annealing atmosphere is humid 4%H-2-N-2. When CSD-derived STO-Ni is used as a template, biaxially oriented LMO buffer layers with c-axis orientation can be successfully prepared. The results provide an effective route to prepare LMO-based buffer layers using CSD.
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Shi Xue Dou
In this work, the authors report on significant flux pinning enhancement in MgB2 that has been easily obtained using a liquid additive, silicon oil. MgB2 bulk samples with 0 up to 30 wt % silicon oil added were prepared by an in situ reaction. Results showed that the Si and C released from the decomposition of the silicon oil formed Mg2Si and substituted into B sites, respectively. Increasing the amount of the Si oil up to 15 wt % has resulted in the reduction of the lattice parameters, as well as Tc and R(300 K)/R(Tc) values, accompanied by a significant …
Chemical Solution Deposition Of Lamno3-Based Films For Coated Conductors, Dongqi Shi, Xuebin Zhu, Jung Ho Kim, Hechang Lei, Lin Wang, Yuping Sun, Rong Zeng, S. X. Dou
Chemical Solution Deposition Of Lamno3-Based Films For Coated Conductors, Dongqi Shi, Xuebin Zhu, Jung Ho Kim, Hechang Lei, Lin Wang, Yuping Sun, Rong Zeng, S. X. Dou
Shi Xue Dou
LaMnO3-based films were prepared using the chemical solution deposition method. It was found that the films on perovskite oxide single crystal substrates are highly (h00)-oriented when the annealing atmosphere is oxygen or air; however, when the substrate is yttrium-stabilized ZrO2, only the La1-NmO3 films are highly (h00)-oriented, and other LaMnO3-based films are (110)-oriented. Under a reducing annealing atmosphere, the atmosphere must be wet in order to create a suitable oxygen partial pressure to crystallize the LaMnO3-based films. After annealing under a wet reducing atmosphere the LaMnO3-based films are directly deposited on Ni tapes; however, when SrTiO3-buffered Ni types are used, …
Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain
Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain
Shi Xue Dou
Flux-pinning mechanism of MgB2 doped with 10 wt % silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence of the critical current density, jc(B), was analysed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For both types of sintered samples, the temperature dependence of Bsb(T) at low temperature is in good agreement with the δl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. At temperatures close to the critical temperature, however, there is evidence for δTc pinning, …