Fang Geng
材料科学技术（英文）
Three-dimensional honeycomb-structured magnesium (Mg) scaffolds with interconnected pores of accurately
controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactive β-
tricalcium phosphate (β-TCP) coatings were prepared on the porous Mg to further improve its biocompatibility,
and the biodegradation mechanism was simply evaluated in vitro. It was found that the mechanical properties
of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength
similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed
that the human osteosarcoma cells (UMR106) were well adhered and proliferated on the surface of the β-
TCP coated porous Mg, which indicates that the β-TCP coated porous Mg is promising to be a bone tissue
engineering scaffold material.
关键词:
Magnesium
,
Bone tissue engineering
,
β-TCP coating
,
Biocompatibility
材料科学技术（英文）
Three-dimensional honeycomb-structured magnesium (Mg) scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactive beta-tricalcium phosphate (beta-TCP) coatings were prepared on the porous Mg to further improve its biocompatibility, and the biodegradation mechanism was simply evaluated in vitro. It was found that the mechanical properties of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed that the human osteosarcoma cells (UMR106) were well adhered and proliferated on the surface of the beta-TCP coated porous Mg, which indicates that the beta-TCP coated porous Mg is promising to be a bone tissue engineering scaffold material.
关键词:
Magnesium;Bone tissue engineering;beta-TCP coating;Biocompatibility;simulated body-fluid;mechanical-properties;cancellous bone;foam;scaffolds;magnesium;hydroxyapatite;porosity;bioceramics;fabrication;ph
Electrochimica Acta
A carbon coated Li3V2(PO4)(3) cathode material for lithium ion batteries was synthesized by a sol-gel method using V2O5, H2O2, NH4H2PO4, LiOH and citric acid as starting materials, and its physicochemical properties were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), transmission electron microscope (TEM), and electrochemical methods. The sample prepared displays a monoclinic structure with a space group of P2(1)/n, and its surface is covered with a rough and porous carbon layer. In the voltage range of 3.0-4.3 V, the Li3V2(PO4)(3) electrode displays a large reversible capacity, good rate capability and excellent cyclic stability at both 25 and 55 degrees C. The largest reversible capacity of 130 mAh g(-1) was obtained at 0.1C and 55 degrees C, nearly equivalent to the reversible cycling of two lithium ions per Li3V2(PO4)(3) formula unit (133 mAh g(-1)). It was found that the increase in total carbon content can improve the discharge performance of the Li3V2-(PO4)(3) electrode. In the voltage range of 3.0-4.8 V, the extraction and reinsertion of the third lithium ion in the carbon coated Li3V2(PO4)(3) host are almost reversible, exhibiting a reversible capacity of 177 mAh g(-1) and good cyclic performance. The reasons for the excellent electrochemical performance of the carbon coated Li3V2(PO4)(3) cathode material were also discussed. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
Li3V2(PO4)(3);sol-gel method;carbon surface layer;electrochemical;performance;lithium-ion batteries;carbothermal reduction method;state synthesis;routine;vanadium fluorophosphate;electrode materials;phosphates;lifepo4;li3fe2(po4)(3);composites;insertion
杨金瑞
,
余尚先
,
顾江楠
高分子材料科学与工程
通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.
关键词:
羟甲基酚化合物
,
羟甲基酚树脂
,
DEPT135
,
结构参数
Science
Strengthening materials traditionally involves the controlled creation of internal defects and boundaries so as to obstruct dislocation motion. Such strategies invariably compromise ductility, the ability of the material to deform, stretch, or change shape permanently without breaking. Here, we outline an approach to optimize strength and ductility by identifying three essential structural characteristics for boundaries: coherency with surrounding matrix, thermal and mechanical stability, and smallest feature size finer than 100 nanometers. We assess current understanding of strengthening and propose a methodology for engineering coherent, nanoscale internal boundaries, specifically those involving nanoscale twin boundaries. Additionally, we discuss perspectives on strengthening and preserving ductility, along with potential applications for improving failure tolerance, electrical conductivity, and resistance to electromigration.
关键词:
strain-rate sensitivity;stacking-fault energy;nano-scale twins;cu-al;alloys;nanocrystalline metals;mechanical-properties;activation;volume;copper;deformation;behavior
Chinese Journal of Inorganic Chemistry
A carbon-coated Li3V2(PO4)(3) Composite cathode material was synthesized by a sol-gel method using V2O5, LIOH center dot H2O, H2O2, NH4H2PO4 and citric acid as starting materials. Properties of the prepared composite material were investigated using XPS, XRD, SEM, Raman spectroscopy, TEM, and various electrochemical techniques. The relationship among structure, calcination temperature, electronic conductivity and the electrochemical performance of samples was also studied. The sample obtained had a monoclinic structure with a space group of P2(1)/n and a rough and porous carbon surface layer. The electronic conductivity of the carbon-coated Li3V2(PO4)3 samples synthesized at 800 degrees C was about a factor of similar to 10(4) higher than that of carbon-free Li3V2(PO4)(3) prepared by solid-state hydrogen reducing reaction. The results show that the carbon-coated Li3V2(PO4)(3) is superior in the electrochemical performance to the carbon-free sample. In the voltage range of 3.0 similar to 4.3 V, the carbon-coated Li3V2(PO4)(3) synthesized at 800 degrees C displays large reversible capacities (128 mAh center dot g(-1) at 0.1C and 109 mAh center dot g(-1) at 2C, respectively) and excellent cyclic stability. The reason for the excellent electrochemical performance of the carbon coated Li3V2(PO4)(3) is discussed.
关键词:
Li3V2(PO4)(3);sol-gel method;carbon-coated;lithium-ion batteries;state synthesis routine;electrochemical performance;high-capacity;lifepo4;pyrolysis;precursor;surface;xps;fe
Andrej Atrens
材料科学技术（英文）
Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.
关键词:
Stress corrosion cracking
,
null
,
null
