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
Hanwei HE
,
Kechao ZHOU
材料科学技术（英文）
A new method for preparation of TaC coating on C/C composite material is reported. The amorphous ethylate tantalum jellied as the precursor is prepared and spread densely on the surface of the C/C composite material so as to form a multilayer film. In a graphitization furnace the multilayer film is transformed into TaC coating at various temperatures. Ethylate tantalum film is characterized by FT-IR (Fourier transform infrared) spectra, XRD (X-ray diffraction) and SEM (scanning electron microscopy) and TaC coating is characterized by XRD and SEM. At 1200℃ the coating contained TaC and Ta¬2O5, and at above 1400℃ only TaC is formed. The coating formed at 1600℃ is a continuous stratum structure, and that formed at 1600℃ is a porous net structure. Analysis on thermodynamics and formation mechanism of TaC indicates that, after ethylate tantalum is decomposed, Ta2O¬5 is first produced and then transformed into Ta2C, and newly formed Ta2C is transformed into TaC by the sufficient C at last.
关键词:
C/C composite
,
composite
,
material
,
TaC
,
coating
,
ethyl
Y.G. Cao
,
X.Y. Sun
金属学报(英文版)
J-integral and crack opening displacement δ(COD) were important parameters for characterization of fractures in engineering materials. The relationship between J-integral and COD has been investigated for a long time and was enerally represented as J = m σyδ, where σy is the yield strength and m is a function of specimen geometry and material properties. To determine the value of m, extensive studies and experiments have been performed. The method that used the fracture-surface topography analysis (FRASTA) for determining J-integral from fracture surfaces of materials was introduced. On the basis of the relationship between COD and fracture surface average profile, the relationship between J-integral and COD was deduced and compared with the generally used equation. The method was experimentally confirmed to be able to provide a new way to determine the relationship between J-integral and COD.
关键词:
FRASTA
,
null
,
null
姜志进
原子核物理评论
在核吸收与随动者吸收理论的基础上,给出了在有QGP相变情况下高能重离子碰撞中的J/Ψ微分产生截面,并用其讨论了CERN的NA50合作组给出的入射动量为158 AGeV/c的Pb-Pb碰撞中的J/Ψ反常抑制现象。理论较好地解释了实验结果。
关键词:
J/Ψ反常抑制
,
核吸收
,
随动者
吉日木图
原子核物理评论
研究自旋和轨道量子数不同的介子之间的质量劈裂对检验夸克势模型非常重要.在以往的夸克势模型计算中,η_c-J/ψ的质量劈裂都很难达到实验的值.用正规化形状因μ~2/(q~2+μ~2),在对完整的动量空间中的Breit夸克势实施一次正规化下研究了η_c-J/ψ和新介子ηb与Υ(1s)之间的质量劈裂.结果表明,正规化形状因子中的屏蔽质量μ应与介子折合质量有关,当将其展开为介子折合质量的三阶多项式时,上述介子质量劈裂可以精确重现实验的结果.另外,由于完整的Breit 势包含有自旋一轨道耦合相互作用的项,因而还可以研究χ_(c0),χ_(c1)和χ_(c2)之间的质量劈裂.
关键词:
夸克势模型
,
矩阵元
,
介子束缚态
,
正规化
,
质量劈裂
董元篪
,
魏寿昆
,
彭(忄育)强
,
朱元凯
金属学报
<正> As一向认为是钢铁中的有害元素。除少数耐腐蚀钢种外,脱As是钢铁冶炼的一个问题。欲脱As必先知As在铁液中的热力学行为。文献中只报道过As的活度相互作用系数e_(As)~C,e_(As)~S及e_(As)~N。本文是继续前文研究As在Fe液中的热力学行为,旨在利用下列反应: 3(CaC_2)+2[As]=(Ca_3As_2)+6[C] (1) 求出Fe-As-C-j熔体中的
关键词:
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
陈建刚
,
卢凤双
,
张敬霖
,
张建生
,
张建福
金属功能材料
3J33(C)马氏体时效钢是以无碳(或超低碳)铁镍马氏体为基体的时效强化型高弹性合金.采用工业电炉处理合金,高温固溶处理后,再经过4次变温循环相变,基体组织由高温固溶后220 μm的粗大等轴晶细化为15 μm左右的均匀细小晶粒.进一步时效处理后,合金抗拉强度、屈服强度、弹性极限、硬度提高10%以上,断面收缩率、断后伸长率、冲击吸收功提高30%以上.
关键词:
马氏体时效钢
,
变温循环相变
,
时效
,
力学性能
