Author
Xu Ke-Wei
Other affiliations: Chang'an University
Bio: Xu Ke-Wei is an academic researcher from Xi'an Jiaotong University. The author has contributed to research in topics: Thin film & Sputter deposition. The author has an hindex of 13, co-authored 55 publications receiving 468 citations. Previous affiliations of Xu Ke-Wei include Chang'an University.
Topics: Thin film, Sputter deposition, Grain growth, Crystallite, Creep
Papers published on a yearly basis
Papers
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TL;DR: In this article, the surface energies for 38 surfaces of fcc metals were calculated by using the modified embedded-atom method and the results showed that the average values of the surface energy are very close to the polycrystalline experimental data.
Abstract: The surface energies for 38 surfaces of fcc metals Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Rh and Ir have been calculated by using the modified embedded-atom method. The results show that, for Cu, Ag, Ni, Al, Pb and Ir, the average values of the surface energies are very close to the polycrystalline experimental data. For all fcc metals, as predicted, the close-packed (111) surface has the lowest surface energy. The surface energies for the other surfaces increase linearly with increasing angle between the surfaces (hkl) and (111). This can be used to estimate the relative values of the surface energy.
67 citations
TL;DR: The main aims of this article were to examine the Sr-HAC's in vitro biocompatibility, including acute toxicity, hemolytic reaction, pyrogen reaction, and cytoxicity, and to evaluate its in vivo degradability during intramuscular and femur implantation, and also to investigate the influence of Sr doses on these properties.
Abstract: In previous studies, we developed a new type of Sr-incorporated hydroxyapatite cement (Sr-HAC), which was shown to have many excellent physiochemical properties, by an ionic cement route (Guo et al., Biomaterials 2005;26:4073-4083). As a further study, the main aims of this article were to examine the Sr-HAC's in vitro biocompatibility, including acute toxicity, hemolytic reaction, pyrogen reaction, and cytoxicity, to evaluate its in vivo degradability during intramuscular and femur implantation, and also to investigate the influence of Sr doses on these properties. The in vitro results show that all of the Sr-HAC samples exhibit satisfactory biocompatibility, and the Sr/(Sr+Ca) molar ratio has an important effect on these properties. For example, the Sr-HAC with a Sr/(Sr+Ca) molar ratio of 5% (5% Sr-HAC) has higher biocompatibility than both the one with a Sr/(Sr+Ca) molar ratio of 10% (10% Sr-HAC) and the Sr-free one. The in vivo results of both the rabbit intramuscular and femur implantation experiments show that the Sr-HAC samples exhibit a much faster degradation rate than the Sr-free one, and that this also depends on the Sr/(Sr+Ca) molar ratio. Specifically, the mean degradation rate of the 10% Sr-HAC increases by an amplitude of 73.9 wt % compared with that of the Sr-free HAC. In addition, the optical transmission photographs show that the Sr doses play an important role on the interface between the implants and the new bone. The energy dispersion X-ray spectrum analysis indicates that there exists a gradient distribution of Sr element in the tight and bioactive interface between the implants and new bone, indicating that the Sr element takes a share in the mineralization of the new bone together with Ca element. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
60 citations
TL;DR: In this article, solid diffusion process was used to form a diffusion alloying layer on the surface of ZM5 magnesium alloy to improve corrosion and wear resistance, which was mainly composed of Mg-Al-Zn intermetallic compounds and Mg−Al−Zn solid solution transition zone.
Abstract: In this research, solid diffusion process was used to form a diffusion alloying layer on the surface of ZM5 magnesium alloy to improve corrosion and wear resistance. It is shown that the solid diffusion layer was mainly composed of Mg–Al–Zn intermetallic compounds and Mg–Al–Zn solid solution transition zone that had more Zn and Al elements than untreated ZM5 magnesium substrate. The continued immersion test in 3% NaCl solution displayed that the diffusion-treated specimen had better corrosion resistance compared to the untreated ZM5 specimen. The polarization test indicated that the Mg–Al–Zn intermetallic compounds of the diffusion alloying layer were an effective corrosion barrier to decrease the corrosion rate for ZM5 magnesium alloy when exposed to 3% NaCl solutions. In addition, the microhardness values of the Mg–Al–Zn intermetallic compounds were much higher than those of the substrate and this would greatly contribute to the enhancement of wear resistance.
46 citations
TL;DR: In this paper, the authors used a nanoindentation instrument to study the penetration depth and the stress exponent of Cu at low and high loads, and found that penetration depth was time-dependent and serrated at low loads.
40 citations
TL;DR: Investigation of mechanical properties and microstructures of the CPC/PLGA composite immersed in 0.9% saline solution for different time and its in vivo degradation behaviors after implanting in rabbit muscle and femur bone showed that the composite exhibits outstanding biocompatibility and bioactivity and more excellent osteoconduction and degradability than the pure CPC.
Abstract: A new type of bone cement composite was successfully achieved by mixing degradable biosecure polylactic-co-glycolic acid (PLGA) fibers with high initial strength calcium phosphate cement (CPC). Its higher initial strength was mainly responsible for the in situ reinforcing effect of residual tetra-calcium phosphate monoxide (r-TTCP) particles reported in our previous work. So this bone cement composite containing fibers and the controlling group could be termed as CPC/PLGA composite and pure CPC or fiber-free group, respectively. In this study, we had investigated mechanical properties and microstructures of the CPC/PLGA composite immersed in 0.9% saline solution for different time and its in vivo degradation behaviors after implanting in rabbit muscle and femur bone, respectively. Results showed that the incorporation of the degradable fibers not only greatly increased the initial toughness and flexural strength of the CPC/PLGA composite but also significantly improved its later osteo-conduction as well as degradation rate. The rabbit muscle implant tests showed that the weight loss ratio of the CPC/PLGA composite increased by 41.03% as compared to the pure CPC. And the rabbit femur implant tests showed that the composite exhibits outstanding biocompatibility and bioactivity and more excellent osteoconduction and degradability than the pure CPC.
26 citations
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TL;DR: An overview of the recent results achieved on ion-substituted calcium phosphates prepared at low temperature, i.e. by direct synthesis in aqueous medium or through hydrolysis of more soluble calcium phosphate based materials is provided.
697 citations
TL;DR: An overview on the chemistry, kinetics of setting and handling properties (setting time, cohesion and injectability) of CPCs for bone substitution, with a focus on their mechanical properties shows that, although the mechanical strength of CPC's is generally low, it is not a critical issue for their application for bone repair.
528 citations
TL;DR: An overview of the different approaches taken in the application of calcium phosphate cements for drug delivery in the skeletal system is provided, and the most significant achievements are identified.
459 citations
TL;DR: This study shows that the optimal content of added Sr is 2 wt.% for binary Mg-Sr alloys in the rolled state and that the as-rolled Mg -2Sr alloy in vivo produces an acceptable host response.
380 citations
TL;DR: In this paper, a metal-organic framework-derived nitrogen-doped nanoporous carbon was used as an electrocatalyst for the nitrogen reduction reaction (NRR) by using renewable electricity.
373 citations