28 results on '"Zhong, Hui"'
Search Results
2. Effects of B4C Addition on the Microstructure and Magnetic Properties of FePt-C Granular Thin Films for Perpendicular Magnetic Recording
- Author
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Dedong Yu, Qiang Wang, Yanqing Fu, Zhong Hui, Tongbo Zhang, Weibin Cui, and Xiaoqian Zhou
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010302 applied physics ,Materials science ,Magnetoresistance ,02 engineering and technology ,Coercivity ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Grain size ,Electronic, Optical and Magnetic Materials ,Reflection (mathematics) ,Nuclear magnetic resonance ,0103 physical sciences ,Perpendicular ,Electrical and Electronic Engineering ,Thin film ,Composite material ,0210 nano-technology - Abstract
Effects of B4C addition on the microstructure and magnetic properties of FePt and FePt-C thin films have been studied. A high coercivity of 2.11 T with good squareness is achieved by B4C addition. By analyzing the mechanism and different isolation effects of B4C and C as segregants, a double-layer approach has been developed and a coercivity of 1.96 T is achieved with column-like FePt grains. The grain size and the size distribution are not deteriorated substantially compared with the single-layer case. These results indicate that addition of B4C as segregant is beneficial for the modification of microstructure and magnetic properties.
- Published
- 2017
3. Electrochemical Characteristics of Melt Spun Nanocrystalline and Amorphous Mg20Ni6M4 (M=Co, Cu) Alloys Applied to Ni-MH Battery
- Author
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Dong Liang Zhao, Tai Yang, Guofang Zhang, Yang Huan Zhang, Hong Wei Shang, and Zhong Hui Hou
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Materials science ,Metallurgy ,Alloy ,General Medicine ,engineering.material ,Microstructure ,Electrochemistry ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,engineering ,Melt spinning ,Spinning - Abstract
The melt-spinning technique was used to synthesize the Mg20Ni6M4 (M=Co, Cu) alloys with nanocrystalline and amorphous structure. The microstructures of the as-spun alloys were characterized by XRD and TEM. The electrochemical hydrogen storage properties of the alloys were measured. The results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The discharge capacity and high rate discharge ability (HRD) of the alloys notably augment with the rising of the spinning rate. The action of the melt spinning on the cycle stability of the alloys is associated with the substitution element. For the (M=Co) alloy, the melt spinning exerts a dramatically positive impact, whereas for the (M=Cu) alloy, its impact is negative.
- Published
- 2012
4. Impact of Melt Spinning on Electrochemical Hydrogen Storage Characteristics of Mg20Ni9M1 (M=Cu, Co) Alloys
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Tai Yang, Zhong Hui Hou, Guofang Zhang, Yang Huan Zhang, Hong Wei Shang, and Dong Liang Zhao
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Materials science ,Metallurgy ,Alloy ,General Engineering ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,engineering ,Grain boundary ,Melt spinning ,Spinning - Abstract
The melt-spinning technique is used to fabricate the Mg20Ni9M1 (M=Cu, Co) alloys with nanocrystalline and amorphous structure. The microstructures of the as-spun alloys were characterized by XRD and TEM. The electrochemical hydrogen storage properties of the alloys were measured. The results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure and small amount of amorphous phase is visible on the grain boundaries of the as-spun (M=Co) alloy. The discharge capacity and high rate discharge ability (HRD) of the alloys visibly grow with the rising of the spinning rate. The action of the melt spinning on the cycle stability of the alloys is associated with substitution element. For M=Cu, the capacity retaining rate (SN) evidently falls with the growing of the spinning rate; whereas for M=Co, it first declines and then augments.
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- 2012
5. Electrochemical and Gaseous Hydrogen Storage Capacities of As-Spun Nanocrystalline and Amorphous Mg2Ni0.6M0.4 (M=Cu, Co) Alloys
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Ying Cai, Guofang Zhang, Feng Hu, Xia Li, Yin Zhang, and Zhong Hui Hou
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Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,Desorption ,engineering ,Melt spinning ,Spinning - Abstract
The melt spinning technology was used to prepare the Mg2Ni0.6M0.4 (M=Cu, Co) hydrogen storage alloys in order to obtain a nanocrystalline and amorphous structure. The microstructures of the alloys were characterized by XRD, TEM. The effects of the melt spinning on the electrochemical and gaseous hydrogen storage capacities of the alloys were investigated. The results indicate that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if a limited spinning rate is applied, while the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure and the amount of the amorphous phase grows evidently with the rising of the spinning rate, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning enhances the electrochemical and gaseous hydrogen storage capacities of the alloys dramatically. Simultaneously, it ameliorates the hydriding kinetics of the alloys substantially. As the spinning rate grows from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the discharge capacity increases from 53.3 to 140.4 mAh/g for the (M=Cu) alloy and from 113.3% to 402.5% for the (M=Co) alloy; the gaseous hydrogen desorption capacity ( ) in 100 min augments from 2.29% to 2.87% for the (M=Cu) alloy and from 2.42% to 3.08% for the (M=Co) alloy.
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- 2012
6. Electrochemical Cycle Stability and Kinetics of the As-Cast and Spun La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0-0.2) Alloys
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Le Le Chen, Guofang Zhang, Dong Liang Zhao, Zhong Hui Hou, Yang Huan Zhang, and Xiao Gang Liu
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Materials science ,Metallurgy ,Alloy ,General Engineering ,Electrochemical kinetics ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Chemical engineering ,Electrode ,engineering ,Melt spinning ,High-resolution transmission electron microscopy - Abstract
The poor electrochemical cycle stability of Re-Mg-Ni system A2B7-type electrode alloys has limited their practical application as the negative electrode materials of Ni-MH battery. In order to improve the electrochemical cycle stability of the La-Mg-Ni system A2B7-type electrode alloys, the partial substitution of Zr for La has been performed. The La0.75-xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0–0.2) electrode alloys were fabricated by casting and melt-spinning. The microstructures and the electrochemical cycle stability and kinetics of the alloys were investigated. The structure characterized by XRD, SEM and HRTEM reveals that the as-cast and spun alloys have a multiphase structure, composing of two main phases (La, Mg)2Ni7 and LaNi5 as well as a residual phase LaNi2. The as-spun Zr-free alloy displays an entire nanocrystalline structure, but a like amorphous structure is detected in the as-spun alloy substituted by Zr, suggesting that the substitution of Zr for La facilitates the formation of an amorphous structure. The electrochemical measurement indicates that both the substitution of Zr for La and the melt spinning remarkably ameliorate electrochemical cycle stability of the alloys. Furthermore, the high rate discharge ability (HRD), the electrochemical impedance spectrum (EIS) and the potential-step measurements all indicate that both of the melt spinning and the Zr substitution bring on a notable decline of the electrochemical kinetics of the alloys.
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- 2012
7. Electrochemical Hydrogen Storage Performances of the Nanocrystalline and Amorphous Mg2Ni-Type Alloys
- Author
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Zhong Hui Hou, Tai Yang, Guofang Zhang, Chao Xu, Dong Liang Zhao, and Yang Huan Zhang
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Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,engineering ,Melt spinning ,High-resolution transmission electron microscopy ,Spinning - Abstract
The melt-spinning technique is applied to the preparation of the nanocrystalline and amorphous Mg2Ni-type alloys with nominal compositions of Mg20Ni10-xMnx (x=0, 1, 2, 3, 4). The microstructures of the as-cast and spun alloys were characterized by XRD and HRTEM. The electrochemical performances of the as-spun alloys are measured by an automatic galvanostatic system. The results show that the as-spun Mg20Ni10 alloy displays an entire nanocrystalline structure, whereas the as-spun Mg20Ni6Mn4 alloy exhibits a nanocrystalline and amorphous structure, confirming that the substitution of Mn for Ni facilitates the glass formation in the Mg2Ni-type alloy. And the amorphization degree of the as-spun alloys substituted by Mn increases with the growing of the spinning rate. The substitution of Mn for Ni and the melt spinning ameliorate electrochemical hydrogen storage characteristics of the alloys substantially. The electrochemical discharge capacity and cycle stability of the alloys are considerably enhanced by increasing the amount of Mn substitution and the spinning rate. The high rate discharge ability (HRD) of the alloys first augments and then falls with the growing of the Mn content and the spinning rate.
- Published
- 2012
8. Ameliorated Hydrogen Storage Kinetics of Mg20Ni7M3 (M=Co, Cu) Alloys by Melt Spinning
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Dong Liang Zhao, Tai Yang, Li Cui Chen, Hong Wei Shang, Yang Huan Zhang, and Zhong Hui Hou
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Materials science ,Hydrogen ,Metallurgy ,Alloy ,Analytical chemistry ,chemistry.chemical_element ,General Medicine ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,chemistry ,engineering ,Melt spinning ,Spinning - Abstract
In order to obtain a nanocrystalline and amorphous structure in the Mg2Ni-type alloy, the melt spinning was applied to fabricate the Mg20Ni7M3 (M=Co, Cu) hydrogen storage alloys. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the gaseous and electrochemical hydrogen storage kinetics of the alloys were investigated. The results indicate that the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as spinning rate grows to 20 m/s, while the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if a limited spinning rate is applied, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably ameliorates the gaseous hydriding and dehydriding kinetics of the alloys. The hydrogen absorption ratio ( ) and hydrogen desorption ratio ( ) are enhanced from 81.9% to 94.7% and from 34.9% to 57.3% for the (M=Co) alloy, and from 57.2% to 92.8% and from 21.6% to 49.6% for the (M=Cu) alloy by raising spinning rate from 0 (as-cast was defined as the spinning rate of 0 m/s) to 30 m/s. Furthermore, the high rate discharge ability (HRD), the limiting current density (IL) and the hydrogen diffusion coefficient (D) of the alloys notably increase with the growing of the spinning rate.
- Published
- 2012
9. An Investigation of the Electrochemical Hydrogen Storage Performances of the RE-Mg-Ni-Based A2B7-Type Electrode Alloys Prepared by Melt Spinning
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Dong Liang Zhao, Zhong Hui Hou, Xiao Gang Liu, Le Le Chen, Tai Yang, and Yang Huan Zhang
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Materials science ,Hydrogen ,Metallurgy ,Alloy ,General Engineering ,Limiting current ,chemistry.chemical_element ,engineering.material ,Microstructure ,Hydrogen storage ,chemistry ,Chemical engineering ,Phase (matter) ,engineering ,Melt spinning ,Spinning - Abstract
The RE-Mg-Ni-based A2B7-type La0.75−xPrxMg0.25Ni3.2Co0.2Al0.1 (x = 0, 0.1, 0.2, 0.3, 0.4) electrode alloys were synthesized by melt spinning technology. The impacts of the melt spinning and the substitution of Pr for La on the microstructures and electrochemical characteristics of the alloys were investigated in detail. The results reveal that the as-cast and spun alloys have a multiphase structure, containing two main phases (La, Mg)2Ni7 and LaNi5 as well as a residual phase LaNi2. The melt spinning results in a notable grain refinement of the alloys without altering the phase structure of the alloys. The discharge capacity of the (x=0.1) alloy first mounts up and then falls with rising the spinning rate. And the as-spun (10 m/s) alloy yields the maximum discharge capacity with the variation of Pr content. Furthermore, the measurements of the electrochemical hydrogen storage kinetics reveal that the high rate discharge ability (HRD), the hydrogen diffusion coefficient (D) and the limiting current density (IL) of the alloys first increases then decreases with rising the spinning rate and the amount of Pr substitution.
- Published
- 2012
10. Preparation and Hydrogen Storage Kinetics of Nanocrystalline and Amorphous Mg20Ni10-xMx (M=Co, Cu; x=0-4) Alloys
- Author
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Dong Liang Zhao, Zhong Hui Hou, Hong Wei Shang, Feng Hu, Yang Huan Zhang, and Guofang Zhang
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Materials science ,Hydrogen ,Alloy ,Metallurgy ,General Engineering ,Analytical chemistry ,Electrochemical kinetics ,chemistry.chemical_element ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,chemistry ,engineering ,Melt spinning - Abstract
In order to obtain a nanocrystalline and amorphous structure in the Mg2Ni-type alloy, the Ni in Mg2Ni alloy has been partially substituted by M (M=Co, Cu), and the melt spinning has been used to fabricate the Mg20Ni10-xMx (M=Co, Cu; x=0-4) hydrogen storage alloys. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of substituting Ni with M (M=Co, Cu) on the gaseous and electrochemical hydrogen storage kinetics of the as-spun alloys were investigated. The results indicate that the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, while the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The substitution of M (M=Co, Cu) for Ni exerts a trifling impact on the hydriding kinetics of the alloys, but it renders a marked enhancement of dehydriding capacity and kinetics. Furthermore, the measurements of the high rate discharge ability (HRD) and the hydrogen diffusion coefficient (D) as well as the electrochemical impedance spectra (EIS) of the alloys exhibit that the electrochemical kinetics of the as-spun (30 m/s) alloys is significantly ameliorated by substituting Ni with M (M=Co, Cu).
- Published
- 2012
11. Hydriding and Dehydriding Kinetics of Nanocrystalline and Amorphous Mg20Ni6M4 (M=Cu, Co) Alloys
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Guofang Zhang, Dong Liang Zhao, Ying Cai, Zhong Hui Hou, Yang Huan Zhang, and Hong Wei Shang
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Materials science ,Metallurgy ,Alloy ,General Engineering ,Analytical chemistry ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,engineering ,Melt spinning ,High-resolution transmission electron microscopy ,Spinning - Abstract
It was well known that the Mg2Ni-type alloy with a nanocrystalline/amorphous structure possesses superior hydrogen storage kinetics. In order to obtain a nanocrystalline and amorphous structure, the melt spinning was applied to prepare the Mg2Ni-type Mg20Ni6M4 (M=Cu, Co) hydrogen storage alloys. The microstructures of the as-cast and spun alloys were characterized by XRD, SEM and HRTEM. The gaseous hydriding and dehydriding kinetics of the alloys was measured. The results show that the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as spinning rate approaches to 20 m/s, while the as-spun (M=Cu) alloys hold an entire nanocrystalline structure whatever spinning rate is, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning markedly improves the gaseous hydrogen storage kinetics of the alloys. As the spinning rate grows from 0 (as-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) is enhanced from 57.7% to 91.4% for the (M=Cu) alloy and from 77.1% to 93.5% for the (M=Co) alloy. And hydrogen desorption ratio ( ) is raised from 28.7% to 59.0% for the (M=Cu) alloy and from 54.5% to 70.2% for the (M=Co) alloy, respectively.
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- 2012
12. Improved Physical and Electrochemical Hydrogen Storage Kinetics of the Mg20Ni10-XMx (M=Cu, Co; X=0, 4) Alloys by Melt Spinning
- Author
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Dong Liang Zhao, Li Zhao Guo, Hong Wei Shang, Ying Cai, Yang Huan Zhang, and Zhong Hui Hou
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Materials science ,Metallurgy ,Alloy ,General Engineering ,engineering.material ,Microstructure ,Electrochemistry ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,engineering ,Melt spinning ,Spinning - Abstract
It has come to light that the Mg2Ni-type alloy with a nanocrystalline/amorphous structure possesses superior hydrogen storage kinetics. The Mg2Ni-type Mg20Ni10-xMx (M=Cu, Co; x=0, 4) hydrogen storage alloys were synthesized by a melt-spinning technique. The microstructures of the as-cast and spun alloys were characterized by XRD, SEM and HRTEM. The gaseous and electrochemical hydrogen storage kinetics of the alloys was measured. The results show that whatever spinning rate the as-spun (M=Cu) alloys hold an entire nanocrystalline structure. As spinning rate approaches to 20 m/s, the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Furthermore, such substitution results in the formation of secondary phases Mg2Cu and MgCo2 instead of changing the major phase of Mg2Ni. The melt spinning markedly improves the gaseous and electrochemical hydrogen storage kinetics of the alloys. The hydrogen absorption ratio (R5a ), hydrogen desorption ratio (R20d ) and the high rate discharge ability (HRD) notably mount up with the growing of the spinning rate.
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- 2012
13. Enhanced Electrochemical Hydrogen Storage Characteristics of the as-Spun Mg2Ni-Type Alloys by Substituting Ni with M (M=Cu, Co)
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Bao Wei Li, Dong Liang Zhao, Hui Ping Ren, Zai Guang Pang, Zhong Hui Hou, and Yang Huan Zhang
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Materials science ,Metallurgy ,Alloy ,General Engineering ,Analytical chemistry ,engineering.material ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Phase (matter) ,engineering ,Melt spinning ,High-resolution transmission electron microscopy - Abstract
Mg2Ni-type Mg20Ni10-xMx (M=Cu, Co; x=0, 1, 2, 3, 4) electrode alloys with nanocrystalline and amorphous structure were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by XRD, SEM and HRTEM. The electrochemical hydrogen storage properties of the experimental alloys were measured. The obtained results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Furthermore, such substitution results in the formation of secondary phases Mg2Cu and MgCo2 instead of changing the major phase of Mg2Ni. The substitution of M (M=Cu, Co) for Ni markedly improves the electrochemical performances of the alloys, involving the discharge capacity and the cycle stability as well as the high rate discharge ability.
- Published
- 2012
14. Enhanced Electrochemical Cycle Stability of RE-Mg-Ni System A2B7-Type Alloys by Melt Spinning and Substituting La with Pr
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Le Le Chen, Bao Wei Li, Xiao Gang Liu, Zhong Hui Hou, Yang Huan Zhang, and Hui Ping Ren
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Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Microstructure ,Casting ,Chemical engineering ,Phase (matter) ,Electrode ,engineering ,Melt spinning ,High-resolution transmission electron microscopy ,Spinning - Abstract
The poor electrochemical cycle stability of RE–Mg–Ni system A2B7-type electrode alloys have limited their practical application as the negative electrode materials of Ni–MH battery. In order to improve the electrochemical cycle stability of the La–Mg–Ni system A2B7-type electrode alloys, the partial substitution of Pr for La has been performed. The La0.75−xPrxMg0.25Ni3.2Co0.2Al0.1 (x = 0–0.4) electrode alloys were fabricated by casting and melt-spinning. The microstructures and electrochemical cycle stability of the as-cast and spun alloys were investigated by XRD, SEM and HRTEM. The results show that the as-cast and spun alloys have a multiphase structure, consisting of two main phases (La, Mg)2Ni7 and LaNi5 as well as a residual phase LaNi2. The substitution of Pr for La brings on a notable grain refinement of the as-cast alloys instead of altering the phase structure of the alloys. The electrochemical measurement indicates that the cycle stability of the alloy remarkably grows with increasing both Pr content and spinning rate. The substitution of Pr for La and the melt spinning significantly ameliorate electrochemical cycle stability of the alloys. The capacity retaining rate (S100) of the as-spun (15 m/s) alloys at 100th charging/discharging cycle is enhanced from 72.38% to 90.33% by increasing Pr content from 0 to 0.4. And that of the Pr0.3 alloy is increased from 78.11% to 92.32% by growing spinning rate from 0 (as-cast was defined as the spinning rate of 0 m/s) to 20 m/s.
- Published
- 2011
15. Gaseous and Electrochemical Hydrogen Storage Performances of Nanocrystalline and Amorphous Mg20-xLaxNi10(x=0-6) Alloys Prepared by Melt-Spinning
- Author
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Yang Huan Zhang, Zai Guang Pang, Hui Ping Ren, Bao Wei Li, Zhong Hui Hou, and Yin Zhang
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Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Electrochemistry ,Microstructure ,Nanocrystalline material ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,engineering ,Melt spinning ,Spinning - Abstract
The nanocrystalline and amorphous Mg2Ni-type Mg20-xLaxNi10 (x = 0, 2, 4, 6) hydrogen storage alloys were prepared by melt-spinning technology. The microstructures and hydrogen storage performances of the alloys were characterized. The results show that no amorphous phase is detected in the as-spun La-free alloy, but the as-spun alloys substituted by La hold a major amorphous phase, confirming that the substitution of La for Mg increases the glass forming ability of the Mg2Ni-type alloy. Melt-spinning remarkably improves the hydrogen storage performances of the alloys. When the spinning rate increases from 0 (As-cast was defined as spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption capacity of the alloy (x = 2) at 200°C and 1.5 MPa in 10 min rises from 1.26 to 2.60 wt%, and its electrochemical discharge capacity grows from 197.2 to 406.5 mAh/g at a current density of 20 mA/g.
- Published
- 2011
16. Electrochemical Hydrogen Storage Characteristics of (Mg1-XZrX)2Ni (x = 0 - 0.3) Alloys Prepared by Mechanical Alloying
- Author
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Shi Hai Guo, Dong Liang Zhao, Guofang Zhang, Yang Huan Zhang, Xia Li, and Zhong Hui Hou
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Discharge potential ,Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Electrochemistry ,Microstructure ,Amorphous solid ,Hydrogen storage ,Chemical engineering ,Phase (matter) ,Electrode ,engineering - Abstract
The electrode alloys (Mg1-xZrx)2Ni (x = 0, 0.3) were prepared by mechanical alloying (MA). Mg in the alloy was partially substituted by Zr in order to improve the electrochemical hydrogen storage characteristics of the Mg2Ni-type alloy. The effects of substituting Mg with Zr as well as milling duration on the microstructures and electrochemical performances of the alloys were investigated in detail. The results showed that the substitution of Zr facilitates the formation of amorphous Mg2Ni-type phase. The electrochemical measurement indicated that the substitution of Zr significantly enhances the discharge capacity and cycle stability of the alloys, and it markedly improved the discharge potential characteristic of the alloys. For a fixed alloy, the electrochemical performances, including the cycle stability and the discharge voltage characteristic as well as discharge capacity, of the alloys were markedly improved with prolonging of the ball-milling duration.
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- 2011
17. Effect of annealing on photoluminescence and microstructures of InGaN/GaN multi-quantum well with Mg-doped p-type GaN
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Yang Zhi-Jian, Feng Yu-Chun, Yu Tong-Jun, Niu Hanben, Li Zhong-Hui, Guo Bao-ping, and Zhang Guo-Yi
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Photoluminescence ,Materials science ,business.industry ,Annealing (metallurgy) ,Doping ,General Physics and Astronomy ,Microstructure ,Quantum size effect ,symbols.namesake ,Stark effect ,symbols ,Optoelectronics ,Metalorganic vapour phase epitaxy ,business ,Quantum well - Abstract
InGaN/GaN multi-quantum well structure with Mg-doped p-type GaN was grown by low-pressure metalorganic vapour phase epitaxy. After rapid-thermal-annealing at 700 and 900 degrees C, both the red-shift and the blue-shift of the photoluminescence (PL) peak, the decreased and the enhancement of the PL intensity were observed. The transmission electron microscopic images showed that InGaN multi-quantum-dots-like (MQD-like) structures with dimensions less than 5×10nm were formed in InGaN wells. The changes of PL spectra could be tentatively attributed to the competition between the red-shift mechanism of the quantum-confined Stark effect and the blue-shift mechanism of the quantum size effect due to MQD-like structures.
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- 2005
18. Effects of B4C Addition on the Microstructure and Magnetic Properties of FePt-C Granular Thin Films for Perpendicular Magnetic Recording.
- Author
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Yu, Dedong, Zhou, Xiaoqian, Zhang, Tongbo, Zhong, Hui, Fu, Yanqing, Cui, Weibin, and Wang, Qiang
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GRANULAR materials ,THIN films ,MAGNETIC recorders & recording ,ANISOTROPY ,MICROSTRUCTURE - Abstract
Effects of B4C addition on the microstructure and magnetic properties of FePt and FePt-C thin films have been studied. A high coercivity of 2.11 T with good squareness is achieved by B4C addition. By analyzing the mechanism and different isolation effects of B4C and C as segregants, a double-layer approach has been developed and a coercivity of 1.96 T is achieved with column-like FePt grains. The grain size and the size distribution are not deteriorated substantially compared with the single-layer case. These results indicate that addition of B4C as segregant is beneficial for the modification of microstructure and magnetic properties. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
19. Dynamic splitting tensile behaviour of engineered geopolymer composites with hybrid polyvinyl alcohol and recycled tyre polymer fibres.
- Author
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Zhong, Hui and Zhang, Mingzhong
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POLYVINYL alcohol , *COMPUTED tomography , *STRAIN rate , *INORGANIC polymers , *FIBERS , *DYNAMIC loads , *SCANNING electron microscopy , *POLYMERIC composites - Abstract
Partial replacement of the widely used polyvinyl alcohol (PVA) fibre in engineered geopolymer composites (EGC) with recycled fibres can reduce the material cost and improve sustainability. This study investigates the effect of hybrid PVA and recycled tyre polymer (RTP) fibre content on the quasi-static and dynamic splitting tensile behaviour and microstructure of ambient-cured fly ash-slag based EGC through split Hopkinson pressure bar, scanning electron microscopy and X-ray computed tomography tests. Results indicate that the presence of PVA or RTP fibres can considerably improve the quasi-static and dynamic splitting tensile behaviour of geopolymers. All investigated mixtures are characterised by remarkable strain rate sensitivity within the considered test range, which can be well described using the proposed relationship between dynamic increase factor and strain rate for predictions of dynamic properties. Replacing PVA fibre with 0.25–0.5% RTP fibre can lead to better dynamic splitting tensile properties of EGC compared to that with 2.0% PVA fibre, which can be mainly ascribed to the improved synergistic effect of hybrid fibres in controlling the cracks. The microscopic images reveal that the failure mode of RTP fibres is not sensitive to the strain rate due to its hydrophobic surface feature, which could benefit the energy absorption capacity of EGC under dynamic loading. EGC containing hybrid PVA and RTP fibres holds promise as a cost-effective and sustainable material for applications against dynamic loadings. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
- View/download PDF
20. Synthesis and electromagnetic properties of ferroelectric–ferromagnetic composite material
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Zhong, Hui and Zhang, Huaiwu
- Subjects
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FERROELECTRIC crystals , *ISOSTATIC pressing , *ELECTROMAGNETIC interference , *MICROSTRUCTURE - Abstract
Abstract: Ferroelectric–ferromagnetic composite materials which possess both capacitive and inductive properties for suppressing electromagnetic interference (EMI) were synthesized by usual ceramic technology. These composite materials have relatively high dielectric constant () and high relaxation frequency (fr>1.8GHz). The influences of different composition on the electromagnetic properties of composite materials were investigated. The microstructures of the sintered ceramics were observed and analyzed by SEM. It was found that the average grain size of sintered ceramics was smaller than 5μm and the densities ranged from 4.9 to 5.3g/cm3. [Copyright &y& Elsevier]
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- 2005
- Full Text
- View/download PDF
21. Effects of different sintering temperature and Mn content on magnetic properties of NiZn ferrites
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Zhong, Hui and Zhang, Huaiwu
- Subjects
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FERRITES , *MAGNETIC properties , *IRON metallurgy , *MICROMECHANICS - Abstract
Abstract: Mn-doped NiZn ferrites with compositions of Ni0.44Zn0.56MnxFe2-xO4 (where , 0.05, 0.10 and 0.15) were prepared by conventional ceramic technology. The effects of different sintering temperature (Ts) such as 1180, 1220 and 1260°C and Mn content on magnetic properties of the above series of samples were investigated. Initial permeability increases with the increasing of Mn content at and 1260°C, but decreases at °C. In addition, all Mn substituted ceramic samples especially sintered at 1220°C possess higher quality factor (Q factor) than the NiZn ferrites with no Mn content. [Copyright &y& Elsevier]
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- 2004
- Full Text
- View/download PDF
22. Self-assembly of spherically hollow ammonium perchlorate architectures: Preparation, characterization, and thermal decomposition performance.
- Author
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Cheng, Zhipeng, Wang, Yi, Zhang, Yu, Gao, Yuan, Sha, Zhengyue, Xiao, Zhirou, Dai, Benlin, and Zhong, Hui
- Subjects
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AMMONIUM perchlorate , *SALTING out (Chemistry) , *SOLID propellants , *SUPERSATURATION , *DIMETHYL sulfoxide , *PROPELLANTS , *CRYSTAL growth - Abstract
[Display omitted] • A novel spherical AP architectures was constructed. • DMSO serves as a solvent while OA is an antisolvent. • AP crystal nucleus grows on the DMSO droplet surface. • The thermal decomposition performance was improved. Ammonium perchlorate (AP) is the most common oxidant of composite solid propellants, and its morphology significantly affects its performance. The acquisition of regular spherical APs has always been an urgent but challenging task. In this work, spherical APs with hollow architectures were prepared by adopting a fast and facile antisolvent crystallization strategy, in which dimethyl sulfoxide (DMSO) and oleic acid (OA) were used as the solvent and antisolvent, respectively. The OA antisolvent could temporally stabilize the AP-DMSO droplets and form metastable microreactors for AP crystal growth on the OA/DMSO droplet interfaces. The as-obtained AP products presented well-preserved spherically hollow architectures assembled by abundant small subunits. Crystallization supersaturation was determined to be the main influencing factor. High supersaturation yielded large spherically hollow APs assembled from rod-like subunits, whereas low supersaturation obtained small spherically hollow APs assembled from ellipsoid-like subunits. Then, the thermal decomposition performance of representative spherical APs with hollow architectures was investigated. The proposed method not only provided a rapid synthetic route to high-quality spherical APs but could also be generalized in the preparation of other spherical crystalline materials. The spherical APs with hollow architectures are expected to have wide application prospects in the field of composite solid propellants. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. A facile and novel synthetic route to nanoflowers
- Author
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Cheng, Zhipeng, Xu, Jiming, Zhong, Hui, Li, Dong, Zhu, Pengcheng, and Yang, Yi
- Subjects
- *
NANOSTRUCTURED materials , *OPTICAL diffraction , *FOURIER transform infrared spectroscopy , *THERMOGRAVIMETRY , *TRANSMISSION electron microscopes , *SCANNING electron microscopes , *SPECTRUM analysis - Abstract
Abstract: Ni(OH)2 nanoflowers with thin nanosheets as building blocks were synthesized using a homogeneous precipitation method with NH4F as a complexing agent and a NH4OH solution as an OH− supplier in an aqueous NiCl2 solution. A series of techniques, including X-ray diffraction, fourier transform infrared spectroscopy, thermogravimetric analysis, high-resolution transmission electron microscopy, field-emission scanning electron microscope, and UV–Vis spectroscopy, was used to characterize the nanoflowers. Investigations on the formation process of the flowers indicated that NH4F is vital to the formation of the special flower-like microstructures. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
24. Self-assembly of - nanoparticles into rice ball shaped microstructures via a pyrolytic route
- Author
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Cheng, Zhipeng, Xu, Jiming, Zhong, Hui, Yang, Yi, and Chen, Weifan
- Subjects
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NANOPARTICLES , *FERRIC oxide , *MOLECULAR self-assembly , *PYROLYSIS , *MICROSTRUCTURE , *X-ray diffraction , *X-ray photoelectron spectroscopy , *SCANNING electron microscopy , *THERMOGRAVIMETRY - Abstract
Abstract: Rice ball shaped - Fe2O3 microstructures have been synthesized using a single-step Fe(NO3)3 solution calcination route without the assistance of any other additions. A series of techniques, including XRD, XPS, FE-SEM and DLS ones, were used to characterize the product. Thermogravimetric (TG) analysis provided insight into the decomposition process of the Fe(NO3)3 precursor. A possible growth mechanism of the rice ball shaped - Fe2O3 microstructures was explained. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
25. Fabrication and photocatalytic activity of a novel porous AgBr microstructure.
- Author
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Ju, Chengjia, Cheng, Zhipeng, Zhao, Pusu, Chu, XiaoZhong, Zhong, Hui, Zhang, Lili, and Xu, Jiming
- Subjects
- *
SILVER metallurgy , *PHOTOCATALYTIC oxidation , *RHODAMINE B , *PHOTOCATALYSTS , *POLLUTANTS - Abstract
Highlights • Porous AgBr is synthesized through a facile two-step method. • AgBr/AgCl alloy is used as a sacrificing template. • Porous AgBr exhibits enhanced photocatalytic activity and recyclability. Abstract A novel porous AgBr microstructure with an average diameter of 1–4 μm was prepared for the first time through a facile two-step method, including the formation of AgBr/AgCl alloyed materials and the subsequent removal of AgCl. Field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS) were utilized to characterize the morphology, phase structure and elemental composition of the as-prepared products, respectively. The photocatalytic activity of the as-prepared products was investigated by the degradation of rhodamine B (RhB) under visible-light irradiation. The porous AgBr microstructure significantly enhanced the photocatalytic activity compared with AgCl and AgBr/AgCl alloys. The porous AgBr photocatalyst has potential application on pollutant degradation under sunlight. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Synthesis of quasi-spherical AgBr microcrystal via a simple ion-exchange route.
- Author
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Cheng, Zhipeng, Chu, XiaoZhong, Sheng, Zhenhuan, Xu, Jiming, Zhong, Hui, and Zhang, Lu
- Subjects
- *
SILVER bromide , *MICROCRYSTALLINE polymers , *ION exchange (Chemistry) , *SILVER chloride , *CETYLTRIMETHYLAMMONIUM bromide , *HYDROTHERMAL synthesis , *WAVELENGTHS - Abstract
Uniform quasi-spherical silver bromide (AgBr) microcrystal was synthesized through a simple ion-exchange route, in which silver chloride (AgCl) was used as the template and cetyltrimethyl ammonium bromide (CTAB) was the Br source. AgBr microcrystal was quasi-spherical with a diameter of approximately 5 μm in the synthesis, CTAB molecules slowly released Br − under hydrothermal condition, and then an ion-exchange reaction with Cl − proceeded at the AgCl surface at the initial stage, Br − then diffused from the AgCl surface to the interior. Finally, Cl − in AgCl structure was consumed completely by Br − , producing pure AgBr. The AgBr product can absorb solar energy with wavelengths shorter than 480 nm, which is consistent with previously reported results. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. Ag/AgBr/rGO nanocomposite: Synthesis and its application in photocatalysis.
- Author
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Meng, Xian-hua, Shao, Xin, Li, Huai-yong, Yin, Jie, Wang, Jie, Liu, Feng-zhen, Liu, Xue-hua, Wang, Min, and Zhong, Hui-ling
- Subjects
- *
NANOCOMPOSITE materials , *SILVER bromide , *CHEMICAL synthesis , *PHOTOCATALYSIS , *SCANNING electron microscopes , *ADSORPTION (Chemistry) - Abstract
Abstract: Ag/AgBr is a highly efficient visible-light plasmonic photocatalyst but suffers from severe aggregation of the particles. To settle this problem, we simply added a small amounts of graphene oxide (GO) to the Ag/AgBr reaction system. Expectedly, well monodispersed Ag/AgBr particles bonded on the rGO sheets (Ag/AgBr/rGO) was obtained, as observed by SEM. The adsorptive and photocatalytic activities of the as-prepared samples were investigated by degradation of RhB under visible light irradiation. Compared with pure Ag/AgBr, Ag/AgBr/rGO nanocomposite shows enhanced performance in both the adsorptive and photocatalytic activities. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
28. Controllable fabrication of flower-like Co–B microstructures.
- Author
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Xu, Yongai, Cheng, Zhipeng, Lu, Xiaopan, Zhong, Hui, Xu, Jiming, and Huang, Hui
- Subjects
- *
MICROSTRUCTURE , *FABRICATION (Manufacturing) , *CITRATES , *SODIUM compounds , *COLLOIDS - Abstract
Abstract: Flower-like Co–B microstructures were synthesized by using a trace-level sodium citrate-assisted wet chemical route in which Co(OH)2 colloid, KBH4 and polyvinyl pyrrolidone (PVP) were used as Co source, B source, and protective agent, respectively. The Co–B microstructures were composed of numerous smooth nanoflakes that radiated from the center of the microstructure to form a floral pattern with a diameter of 2–3μm. The original Co(OH)2 colloid served as a hard template. The presence of trace concentrations of sodium citrate is indispensable for the preparation of Co–B flowers. Sodium citrate concentration directly influences the shape of the product. High sodium citrate concentration hinders the acquisition of high-quality Co–B flowers. The possible formation mechanism of flower-like Co–B microstructures was presented based on the experimental results. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
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