The vibrational modes of BaTiO3 in different crystalline phases have been investigated by means of density functional theory pseudo potential method.The evidence of tetragonal to orthorhombic and orthorhombic to rhomb...The vibrational modes of BaTiO3 in different crystalline phases have been investigated by means of density functional theory pseudo potential method.The evidence of tetragonal to orthorhombic and orthorhombic to rhombohedral phase transitions present for 8 nm BaTiO3 ceramics further demonstrates that the similar successive transitions in 8 nm BaTiO3 ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions are as those in coarse BaTiO3 ceramics.展开更多
Carbon nitride （CN,） and diamond-like carbon （DLC） coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N2 were used to synthesize CNx to evaluate the relationship ...Carbon nitride （CN,） and diamond-like carbon （DLC） coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N2 were used to synthesize CNx to evaluate the relationship between the atomic percentage of ni- trogen and hemocompatibility. Auger electron spectroscopy and atomic force microscopy indicated atomic percentages of N of 0.12 and 0.22 and that the CNx coatings were smooth. An in vitro study of the hemocompatibility of the coatings revealed that both CNx coatings had better anticoagulant properties and lower platelet adhesion than DLC. Compared with CN0.1〉 the CN0.22 coating showed longer dynamic clotting time （about 42 min）, static clotting time （23.6 min） and recalcification time （45.6 s）, as well as lower platelet adhesion （102 cells μm-2）, aggregation, and activation. The presence of nitrogen in the CNx coatings in- duced their enhanced hemocompatibility compared with DLC.展开更多
文摘为了研究Ba_(1-x)Nd_(2x/3)TiO_3纳米管的铁电性能,以阳极氧化法制备所得Ti O2纳米管为模板,采用水热法在不同Nd(NO_3)_3浓度和不同水热温度下制备出掺钕BaTiO_3纳米管,并利用扫描电子显微镜(SEM)、X线衍射仪(XRD)和铁电分析仪对样品的表面形貌、微观结构和铁电性能进行分析.实验结果表明:较高的Nd(NO_3)_3掺杂浓度和水热反应温度均有利于TiO_2纳米管向Ba_(1-x)Nd_(2x/3)TiO_3纳米管的转变,从而提高Ba_(1-x)Nd_(2x/3)TiO_3纳米管的结晶度.Nd(NO3)3浓度为0.010 mol/L、水热温度为200℃条件下所得Ba_(1-x)Nd_(2x/3)TiO_3纳米管的表面形貌最好,且其电滞回线具有良好的滞后性,表明样品具有优良的铁电性能,剩余极化强度Pr达到0.82μC/cm2,矫顽场Ec为2.390 k V/cm.
基金supported by the National Basic Research Program of China(2002CB613301)the National Natural Science Foundation of China(50872094)Hainan University Research Fund
文摘The vibrational modes of BaTiO3 in different crystalline phases have been investigated by means of density functional theory pseudo potential method.The evidence of tetragonal to orthorhombic and orthorhombic to rhombohedral phase transitions present for 8 nm BaTiO3 ceramics further demonstrates that the similar successive transitions in 8 nm BaTiO3 ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions are as those in coarse BaTiO3 ceramics.
基金supported by the National Basic Research Program of China (Grant No. 2012CB933604)the National Natural Science Foundation of China (Grant No. 11075116),the National Natural Science Foundation of China "The effect of functionalization induced by ion beam on cell and blood compatibility of graphene" (2013)+1 种基金the Open Research Fund of the State Key Laboratory of Bioelectronics, Southeast Universitythe Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, China
文摘Carbon nitride （CN,） and diamond-like carbon （DLC） coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N2 were used to synthesize CNx to evaluate the relationship between the atomic percentage of ni- trogen and hemocompatibility. Auger electron spectroscopy and atomic force microscopy indicated atomic percentages of N of 0.12 and 0.22 and that the CNx coatings were smooth. An in vitro study of the hemocompatibility of the coatings revealed that both CNx coatings had better anticoagulant properties and lower platelet adhesion than DLC. Compared with CN0.1〉 the CN0.22 coating showed longer dynamic clotting time （about 42 min）, static clotting time （23.6 min） and recalcification time （45.6 s）, as well as lower platelet adhesion （102 cells μm-2）, aggregation, and activation. The presence of nitrogen in the CNx coatings in- duced their enhanced hemocompatibility compared with DLC.
