First principle calculation within the Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) using Local Density Approximation as implemented in Quantum ESPRESSO has been significantly used...First principle calculation within the Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) using Local Density Approximation as implemented in Quantum ESPRESSO has been significantly used to investigate the structural and Piezoelectric, properties of Perovskite ZrTi(PbO3)2. From structural properties calculation, the ground state total energy of -2417.12 eV has been obtained which led to an equilibrium lattice constant of a= 5.620Åfor ZrTi(PbO3)2. Our obtained optimized atomic positions and atomic effective charge shows that the optimized ZrTi(PbO3)2 is stable and the Piezoelectric stress tensor is calculated using Berry-phase approach within density functional perturbation theory (DFPT). From our calculation, we have obtained the stress tensor elements with values of d1,5 = 6.81, d3,1 = 1.69, and d3,3 = 6.18, which is in agreement with the values obtained for tetragonal PbTiO3.展开更多
The Zr-rich(Zr0.8Ti0.2)B2 and the Ti-rich(Ti0.8Zr0.2)B2 solid solutions are formed when TiB2 and ZrB2 are hot-pressed.To forecast the properties of the two solid solutions,their valence electron structure was analyzed...The Zr-rich(Zr0.8Ti0.2)B2 and the Ti-rich(Ti0.8Zr0.2)B2 solid solutions are formed when TiB2 and ZrB2 are hot-pressed.To forecast the properties of the two solid solutions,their valence electron structure was analyzed based on the empirical electron theory(EET) of solids and molecules.We used three different models,the average atom model,the average cell model and the real cell model,and compared with the calculation results from the three models.In the real cell model,the lattice constants of the solid solu-tions were supposed to be changed or unchanged.The results showed that different models could only result in slight change in the hybridization levels of the metal atoms in the two solid solutions and little difference between the calculation values.However,they can not change the variant trend of the va-lence electron structure nor the properties of the solid solutions.Thus,the three models and the methods are appropriate and the calculation results are reasonable and consistent.展开更多
以固态氧化物为原料,采用固态合成工艺制备Pb(Zn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(ZrTi)O3(PZN-PNN-PZT)压电陶瓷,并研究了锆钛比(r(Zr)/r(Ti))、Ba2+的A位取代及Ba2+、La3+的A位复合取代对压电陶瓷电性能的影响。结果表明,PZN-PNN-PZT...以固态氧化物为原料,采用固态合成工艺制备Pb(Zn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(ZrTi)O3(PZN-PNN-PZT)压电陶瓷,并研究了锆钛比(r(Zr)/r(Ti))、Ba2+的A位取代及Ba2+、La3+的A位复合取代对压电陶瓷电性能的影响。结果表明,PZN-PNN-PZT压电陶瓷在r(Zr)/r(Ti)=1.03下,进行Ba2+,La3+的A位复合取代后,即式子在Pb0.92Ba0.04La0.04(Ni1/3Nb2/3)y(Zn1/3Nb2/3)z Zrm Tin O3时压电性能最佳,其介电常数εT33/ε0=5 657,压电常数d33=709pC/N,机电耦合系数kp=0.69,品质因数Qm=45,居里温度TC=180.9℃。展开更多
The aim of the present paper is to characterize bioinspired chitosan （CS） ＋ hydroxyapatite （HA） coatings with various components ratio on a zirconium alloy with titanium. The coatings were characterized by FT-IR,...The aim of the present paper is to characterize bioinspired chitosan （CS） ＋ hydroxyapatite （HA） coatings with various components ratio on a zirconium alloy with titanium. The coatings were characterized by FT-IR, SEM, hydrophilic/hydrophobic balance, adherence, roughness, electrochemical stability and in vitro cell response. Electrochemical tests, including potentio- dynamic polarization curves and electrochemical impedance spectroscopy, were performed in normal saline physiological solution. Cell viability of MC3T3-E1 osteoblasts, lactate dehydrogenase, nitric oxide, and Reactive Oxygen Species （ROS） levels, as well as actin cytoskeleton morphology, were evaluated as biological in vitro tests. The results on in vitro cell response indicated good cell membrane integrity and viability for all samples, but an increased cell number, a decreased ROS level and a better cytoskeleton organization were noticed for the sample with a higher CS content. The coating with highest CS concen- tration indicated the best performance based on the experimental data. The highest hydrophilic character, highest resistance to corrosion and best biocompatibility as well recommend this coating for bioapplications in tissue engineering.展开更多
文摘First principle calculation within the Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) using Local Density Approximation as implemented in Quantum ESPRESSO has been significantly used to investigate the structural and Piezoelectric, properties of Perovskite ZrTi(PbO3)2. From structural properties calculation, the ground state total energy of -2417.12 eV has been obtained which led to an equilibrium lattice constant of a= 5.620Åfor ZrTi(PbO3)2. Our obtained optimized atomic positions and atomic effective charge shows that the optimized ZrTi(PbO3)2 is stable and the Piezoelectric stress tensor is calculated using Berry-phase approach within density functional perturbation theory (DFPT). From our calculation, we have obtained the stress tensor elements with values of d1,5 = 6.81, d3,1 = 1.69, and d3,3 = 6.18, which is in agreement with the values obtained for tetragonal PbTiO3.
基金Supported by the National Natural Science Foundation of China (Grant No. 90505015)
文摘The Zr-rich(Zr0.8Ti0.2)B2 and the Ti-rich(Ti0.8Zr0.2)B2 solid solutions are formed when TiB2 and ZrB2 are hot-pressed.To forecast the properties of the two solid solutions,their valence electron structure was analyzed based on the empirical electron theory(EET) of solids and molecules.We used three different models,the average atom model,the average cell model and the real cell model,and compared with the calculation results from the three models.In the real cell model,the lattice constants of the solid solu-tions were supposed to be changed or unchanged.The results showed that different models could only result in slight change in the hybridization levels of the metal atoms in the two solid solutions and little difference between the calculation values.However,they can not change the variant trend of the va-lence electron structure nor the properties of the solid solutions.Thus,the three models and the methods are appropriate and the calculation results are reasonable and consistent.
文摘以固态氧化物为原料,采用固态合成工艺制备Pb(Zn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(ZrTi)O3(PZN-PNN-PZT)压电陶瓷,并研究了锆钛比(r(Zr)/r(Ti))、Ba2+的A位取代及Ba2+、La3+的A位复合取代对压电陶瓷电性能的影响。结果表明,PZN-PNN-PZT压电陶瓷在r(Zr)/r(Ti)=1.03下,进行Ba2+,La3+的A位复合取代后,即式子在Pb0.92Ba0.04La0.04(Ni1/3Nb2/3)y(Zn1/3Nb2/3)z Zrm Tin O3时压电性能最佳,其介电常数εT33/ε0=5 657,压电常数d33=709pC/N,机电耦合系数kp=0.69,品质因数Qm=45,居里温度TC=180.9℃。
文摘The aim of the present paper is to characterize bioinspired chitosan （CS） ＋ hydroxyapatite （HA） coatings with various components ratio on a zirconium alloy with titanium. The coatings were characterized by FT-IR, SEM, hydrophilic/hydrophobic balance, adherence, roughness, electrochemical stability and in vitro cell response. Electrochemical tests, including potentio- dynamic polarization curves and electrochemical impedance spectroscopy, were performed in normal saline physiological solution. Cell viability of MC3T3-E1 osteoblasts, lactate dehydrogenase, nitric oxide, and Reactive Oxygen Species （ROS） levels, as well as actin cytoskeleton morphology, were evaluated as biological in vitro tests. The results on in vitro cell response indicated good cell membrane integrity and viability for all samples, but an increased cell number, a decreased ROS level and a better cytoskeleton organization were noticed for the sample with a higher CS content. The coating with highest CS concen- tration indicated the best performance based on the experimental data. The highest hydrophilic character, highest resistance to corrosion and best biocompatibility as well recommend this coating for bioapplications in tissue engineering.
