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
The high-dense nanocrystalline BaTiO3(BT)ceramics with grain size smaller than 100nm have been successfully prepared by the two step sintering and the spark plasma sintering(SPS)process.The successive transitions in n...The high-dense nanocrystalline BaTiO3(BT)ceramics with grain size smaller than 100nm have been successfully prepared by the two step sintering and the spark plasma sintering(SPS)process.The successive transitions in nanograin BT ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions,similar to those in coarse BT ceramics,were revealed by in-situ temperature dependent Raman spectrum.The multiphase coexistence and the diffused phase transition character were demonstrated in the 8nm nanocrystalline BT ceramics.展开更多
Monolithic ZrB2,W coatings and ZrB2/W multilayers with different modulation periods and modulation ratios were synthesized by ion beam assisted deposition at room temperature and 400°C.X-ray diffraction(XRD),scan...Monolithic ZrB2,W coatings and ZrB2/W multilayers with different modulation periods and modulation ratios were synthesized by ion beam assisted deposition at room temperature and 400°C.X-ray diffraction(XRD),scanning electron microscopy(SEM),surface profiler,and nanoindention were employed to investigate the influences of the deposition temperature and the modulation period on the growth,textures,interface structure,and mechanical properties of the multilayers.The results indicated that the multilayer with modulation period of 13 nm synthesized at room temperature possessed a higher hardness of 23.8 GPa.Deposition temperature gave a significant contribution to mechanical property enhancement.The 400°C-deposition temperature led to a maximum hardness and elastic modulus value of 32.1 and 399.1 GPa for ZrB2/W multilayer with a modulation period of 6.7 nm.Its critical load increased to 42.8 mN and residual stress decreased to-0.7 GPa.A higher deposition temperature can cause an increase in interfacial atomic mixture and mobility of surface species,which induceds an increase in areal atomic density and dislocation pinning.These results as well as small nanoscale grain sizes should be related to hardness increase.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
ZrB2/ZrAlN multilayered coatings with various modulation ratios(t ZrB2:t ZrAlN)and constant modulation periods were prepared by magnetron sputtering system at room temperature.SEM,XRD,surface profiler and nano-indente...ZrB2/ZrAlN multilayered coatings with various modulation ratios(t ZrB2:t ZrAlN)and constant modulation periods were prepared by magnetron sputtering system at room temperature.SEM,XRD,surface profiler and nano-indenter were employed to investigate the influences of tZ rB 2:tZrAlNon the microstructure and mechanical properties of the coatings.Sharp interfaces and nanoscale multilayered modulation were confirmed by SEM.The multilayer with modulation period of 40 nm and ratio of 3:1 displayed the highest hardness(36.4 GPa)and critical fracture load(76.477 mN)with lower stress.The polycrystalline structure and multilayered modulate structure were directly responsible for the enhanced mechanical properties.展开更多
This article concerns the investigation of blood protein adsorption on carbon paper and multi-wall carbon nanotubes(MWCNTs).Mouse fibroblast cell adhesion and growth on MWCNTs was also studied.The results showed that ...This article concerns the investigation of blood protein adsorption on carbon paper and multi-wall carbon nanotubes(MWCNTs).Mouse fibroblast cell adhesion and growth on MWCNTs was also studied.The results showed that fibrinogen adsorption on carbon paper was much lower than that on MWCNTs,which means that platelets readily aggregate on the surface of MWCNTs.Mouse fibroblast cells implanted on MWCNTs tended to grow more prolifically than those implanted on carbon paper.The cell concentration observed on MWCNTs increased from 1.2×105/mL for a single day culture to 2×105/mL for a 7-day culture.No toxicity reaction was observed during the culturing period.These results indicated that MWCNTs possessed excellent tissue compatibility.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("973"Project)(Grant No.2002CB613301)the National Natural Science Foundation of China(Grant No.50872093)
文摘The high-dense nanocrystalline BaTiO3(BT)ceramics with grain size smaller than 100nm have been successfully prepared by the two step sintering and the spark plasma sintering(SPS)process.The successive transitions in nanograin BT ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions,similar to those in coarse BT ceramics,were revealed by in-situ temperature dependent Raman spectrum.The multiphase coexistence and the diffused phase transition character were demonstrated in the 8nm nanocrystalline BT ceramics.
基金supported by the National Natural Science Foundation of China(Grant No.50872094,50872093)the Key Project of Applied Basic and Advanced Technology Research Plan of Tianjin"Design and synthesis of superhard nanomulitilayers with boride layers"(2011)
文摘Monolithic ZrB2,W coatings and ZrB2/W multilayers with different modulation periods and modulation ratios were synthesized by ion beam assisted deposition at room temperature and 400°C.X-ray diffraction(XRD),scanning electron microscopy(SEM),surface profiler,and nanoindention were employed to investigate the influences of the deposition temperature and the modulation period on the growth,textures,interface structure,and mechanical properties of the multilayers.The results indicated that the multilayer with modulation period of 13 nm synthesized at room temperature possessed a higher hardness of 23.8 GPa.Deposition temperature gave a significant contribution to mechanical property enhancement.The 400°C-deposition temperature led to a maximum hardness and elastic modulus value of 32.1 and 399.1 GPa for ZrB2/W multilayer with a modulation period of 6.7 nm.Its critical load increased to 42.8 mN and residual stress decreased to-0.7 GPa.A higher deposition temperature can cause an increase in interfacial atomic mixture and mobility of surface species,which induceds an increase in areal atomic density and dislocation pinning.These results as well as small nanoscale grain sizes should be related to hardness increase.
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.
基金supported by the National Natural Science Foundation of China(Grant No.50872094)the International Collaboration Project of Tianjin Science and Technology Plan(Grant No.07ZCGHHZ01500)Key Project of Applied Basic and Advanced Technology Research Plan of Tianjin"Design and Synthesis of Superhard"Nanomuliti Layers with Boride Layers(2010)
文摘ZrB2/ZrAlN multilayered coatings with various modulation ratios(t ZrB2:t ZrAlN)and constant modulation periods were prepared by magnetron sputtering system at room temperature.SEM,XRD,surface profiler and nano-indenter were employed to investigate the influences of tZ rB 2:tZrAlNon the microstructure and mechanical properties of the coatings.Sharp interfaces and nanoscale multilayered modulation were confirmed by SEM.The multilayer with modulation period of 40 nm and ratio of 3:1 displayed the highest hardness(36.4 GPa)and critical fracture load(76.477 mN)with lower stress.The polycrystalline structure and multilayered modulate structure were directly responsible for the enhanced mechanical properties.
基金Supported by open-program of State Key Laboratory of Bioelectronics,Southeast University.
文摘This article concerns the investigation of blood protein adsorption on carbon paper and multi-wall carbon nanotubes(MWCNTs).Mouse fibroblast cell adhesion and growth on MWCNTs was also studied.The results showed that fibrinogen adsorption on carbon paper was much lower than that on MWCNTs,which means that platelets readily aggregate on the surface of MWCNTs.Mouse fibroblast cells implanted on MWCNTs tended to grow more prolifically than those implanted on carbon paper.The cell concentration observed on MWCNTs increased from 1.2×105/mL for a single day culture to 2×105/mL for a 7-day culture.No toxicity reaction was observed during the culturing period.These results indicated that MWCNTs possessed excellent tissue compatibility.
