Comparative study of oxidation ability between boron-doped diamond （BDD） and lead oxide （PbO_2） electrodes

The electrochemical oxidation capabilities of two high-performance electrodes,the boron-doped diamond film on Ti(Ti/BDD)and the lead oxide film on Ti(Ti/PbO2),were discussed.Hydroxyl radicals(·HO)generated on the electrode surface were detected by using p-nitrosodimethylaniline(RNO)as the trapping reagent.Electrochemical oxidation measurements,including the chemical oxygen demand (COD)removal and the current efficiency(CE),were carried out via the degradation ofp-nitrophenol(PNP)under the galvanostatic condition.The results indicate that an indirect reaction,which is attributed to free hydroxyl radicals with high activation,conducts on the Ti/BDD electrode,while the absorbed hydroxyl radicals generated at the Ti/PbO2 surface results in low degradation efficiency.Due to quick mineralization which combusts PNP to CO2 and H2O absolutely by the active hydroxyl radical directly,the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO2 electrode,notwithstanding the number of hydroxyl radicals produced on PbO2 is higher than that on the BDD surface.     

钙钛矿电子结构的密度泛函理论研究

应用密度泛函理论(DFT)计算方法,优化了K2Ti2O5的稳定几何构型,并计算了此钙钛矿体系的能带结构和态密度等基态物理性质.结果表明,K2Ti2O5属于间接绝缘体氧化物,其理论带隙宽度为2.6 eV.Ti原子处于氧原子的中心,其d轨道分裂为能量较高的eg和能量较低的t2g轨道,各轨道都靠近费米能级变为占据或半占据状态...     

Ti6Al4V合金表面纳米管阵列的制备

以氢氟酸和铬酸为电解液,采用阳极氧化法在Ti6Al4V合金表面制备高密度的纳米管阵列.利用场发射扫描电镜、X射线衍射仪和X射线光电子能谱对多孔氧化膜的形貌和结构进行分析,利用极化曲线和电化学阻抗谱研究了电解液中CrO3的作用机理.结果表明:电解液种类决定能否形成多孔氧化膜,而电解液的浓度影响多孔氧化膜的形貌和孔径大小;纳米管阵列氧化膜主要由大部分非晶态组织的TiO2,Al2O3和少部分晶态的Al2TiO5,Al3Ti5O2,Al2O3组成,氧化膜内的Al,Ti原子比高于基体中的Al,Ti原子比;CrO3浓度的高低会影响氧化膜的结构.     

加热温度对铸态Ti1100氧化及表面形貌的影响

研究了铸态Ti1100在不同温度下保温5小时的氧化增重和表面形貌.结果表明,随着加热温度的升高,铸造Ti1100氧化加重.300℃基本不氧化;500℃-700℃,Ti1100试样增重0.28-0.62%;1100℃氧化增重严重,达到12.73%;钛的氧化增重为吸氧.用JSM-6360LV型扫描电子显微镜观察试样表面形貌,300-600℃氧化膜极薄且致密;700℃试样表面有少量的氧化腐蚀坑,表面较致密;900℃试样表面有较多的突起氧化层,表面不致密;1100℃氧化层为板片状TiO2.氧化过程为高温时,氧化膜晶粒粗大变得疏松,氧通过氧化膜扩散进基体.     

Ti基体上形成微弧氧化膜组成和结构的研究

在甘油磷酸钙和醋酸钙电解液中采用直流电源对纯Ti进行了微弧氧化。采用微弧氧化方法所制备的氧化膜具有粗糙多孔的结构,且微孔直径随着电压的增加而增大。AES分析表明在基体与氧化膜界面发生了扩散,从基体钛到氧化膜的表面氧的浓度逐渐增大,钛的浓度逐渐减小。XPS分析表明氧化膜的组成随着所施加的微弧氧化电压而改变,微弧氧化电压为200V时TiO2、Ti2O3和TiO占Ti的原子百分比分别为72．61％、22．08％和5.31％;当微弧氧化电压为350V时氧化膜表面Ti元素只由TiO2、Ti2O3组成,且占Ti的原子百分比分别为85．48％、14．52％。     

The Theoretical Study of O_2 Adsorption on NiTi (100) and (110) Surfaces

1　IntroductionNiTishapememoryalloyhaswidelybeenusedinmanyfieldsduetoitsexcellentmechanicalproperties ,uniqueshapememoryeffectandsuperelasticity .In 1970’s ,thegoodbiocompatibilityofNiTialloywasdiscoveredanditwasfurtherusedforvariousbiomedicalapplica tions ,suchasorthopaedicsurgery ,cardiovascularandgas trointestinalsurgery[1-4] .Thehighmechanicalpropertiesandbiocompatibilityofthebiomedicalmaterialsarenec essaryfortheirefficientuseinhumanbody .Thecorrosionresistanceofthealloyandthetoxicityo…     

Nanodiamond films deposited at moderate temperature on pure titanium substrate pretreated by ultrasonic scratching in diamond powder suspension

Nanocrystalline diamond （NCD） film deposition on pure titanium and Ti alloys is extraordinarily difficult because of the high diffusion coefficient of carbon in Ti, the large mismatch in their thermal expansion coefficients, the complex nature of the interlayer formed during diamond deposition, and the difficulty to achieve very high nucleation density. In this investigation, NCD films were successfully deposited on pure Ti substrate by using a novel substrate pretreatment of ultrasonic scratching in a diamond powder-ethanol suspension and by a two-step process at moderate temperature. It was shown that by scratching with a 30-μm diamond suspension for 1 h, followed by a 10-h diamond deposition, a continuous NCD film was obtained with an average grain size of about 200 nm. Detailed experimental results on the preparation, characterization, and successful deposition of the NCD films on Ti were discussed.     

PCVD-Ti(CNO)薄膜的性能及结构分析

研究了Ｔｉ（ＣＮ）薄膜内氧的作用,研究结果表明,Ｔｉ（ＣＮ）薄膜内加入氧后可以消除薄膜的柱状晶结构,薄膜的断面呈致密的纤维状组织。随着反应气体中空气或ＣＯ２气体流量的增加,Ｔｉ（ＣＮＯ）薄膜的硬度呈上升趋势,并在空气的流量为４０ｍＬ·ｍｉｎ－１或ＣＯ２的流量为１５ｍＬ·ｍｉｎ－１时（分别约占气体总量的１５％和６％）,薄膜的硬度达到最大值。     

The theoretical study of O<Subscript>2</Subscript> adsorption on NiTi (100) and (110) surfaces

The discrete variational Xa method (DV-Xα) within the framework of density-functional theory was applied to study O₂ molecule adsorption on NiTi (100) and (110) surfaces. The bond order and charge distribution between Ti and O atoms for two possible O₂ molecule adsorption ways on NiTi (100) and (110) surfaces were calculated. It is found that the adsorption way for O−O bond perpendicular to NiTi surface is preferred to that for O−O bond parallel to NiTi surface, and O₂ molecule only interacted with one nearest surface titanium atom during the adsorption process. Mulliken population and the partial density of state analysis show that the interaction between Ti and O atoms is mainly donated by O 2p and Ti 4s electrons on NiTi(110) surface, O 2p and Ti 4s, 4p electrons on NiTi(100) surface, respectively. The total density of state analysis shows that NiTi(100) surface is more favorable for O₂ molecule adsorption. HUA Ying-jie: Born in 1966. Funded by the National Natural Science Foundation of China (No. 50081001)     

Nano K_2Ti_4O_9 Whisker Enhanced Solid Lubrication Coating for Cutting Application

1　IntroductionWiththedevelopmentofmanufactureindustry ,vari ouskindsofmachinesbringgreatconveniencetopeople’slife .Butalongwiththem ,resourcesexhaustionanden vironmentalpollutionhavebroughtsomenegativeeffectstohumanlife .Metalcuttingisthemainbranchofman…     

TiO2/Ti电催化膜电极的制备及其对盐酸四环素废水的处理

为高效降解盐酸四环素(TCH)废水,以氢氧化钠、乙醇和水为溶剂,以平板微孔钛膜为钛源和基膜,采用水热法制备出原位生长二氧化钛纳米线的钛基电催化膜(TiO₂ NWs/Ti膜)。运用扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和电化学测试等手段,对TiO₂ NWs/Ti膜电极的形貌、晶型和电化学性能等进行表征,并以TiO₂ NWs/Ti膜为阳极构建电催化膜反应器(ECMR)处理盐酸四环素废水。结果表明:原位生长的催化剂锐钛矿TiO₂纳米线直径约为40 nm,均匀生长在Ti膜上;负载TiO₂纳米线可以显著提高Ti膜电极的电化学性能和催化活性,在常温常压下,当盐酸四环素废水质量浓度为50 mg/L、停留时间为10 min、电流密度为0.8 mA/cm2、pH值为7.0、Na2SO4质量浓度为15 g/L、溶液体积为100 mL时,盐酸四环素去除率可达99.5%,TOC去除率可以达到70.5%,明显高于Ti膜构建ECMR(40.2%和12.8%),且经过10次重复使用,催化性能基本保持较高水平。     

Ti基系列阳极的制备及电解染料废水实验研究

采用热氧化法制备了Ti／PbO2、Ti／SnO2-Sb2O3／PbO2、Ti／SnO2-Sb2O3／PbO2-Cu、Ti／SnO2-Sb2O3／PbO2-Ni和Ti／SnO2-Sb2O3／PbO2-Fe5种钛基系列阳极,进行电催化氧化处理模拟染料废水酸性品红溶液的实验研究,比较了不同电极的处理效率、反应速率,同时分析了酸性品红降解过程。结果表明：相对于Ti／PbO2和Ti／SnO2—Sb2O3／PbO2阳极,金属掺杂改性电极Ti／SnO2-Sb2O3／PbO2-Fe和Ti／SnO2-Sb2O3／PbO2-Ni对酸性品红有着更好的去除效率和降解速率,而Cu掺杂电极Ti／SnO2-Sb2O3／PbO2-Cu改性效果不明显。5种电极的电催化氧化过程均符合一级动力学模型。酸性品红在Ti／SnO2-Sb2O3／PbO2-Fe阳极上电催化氧化降解过程的紫外-可见光谱图表明在电流密度75mA／cm^2、电解质Na2SO4浓度12g／L的条件下,处理100mg／L的酸性品红模拟废水,60min内其特征吸收峰消失,酸性品红基本去除,但同时生成了部分小分子中间产物。     

含Ti介孔氧化铝分子筛的合成与表征

采用烷氧基金属作铝源、钛源Triton X-100作模板。于室温合成了具有MSU-2结构的含Ti介孔氧化铝分子筛，并用XRD、TEM、N2-吸附和UV-vis DRS对其结构和Ti物种的形态进行了表征．研究结果表明。Ti对氧化铝骨架有稳定作用,引入Ti后,样品的表面积和孔容增加,研究还表明,当wn／wAl≤696时，Ti以孤立的单核物种存在于氧化铝骨架,随Ti含量增加，Ti物种聚集为氧化物簇,与TiO2-Al2O3复合氧化物相比，该氧化物簇在介孔孔壁中更难长大，故当Ti含量较高时，Ti氧化物簇迁移至孔壁表面，造成孔道部分堵塞,但直至n／wAl=33％,未见明显的TiO2晶相出现,表明介孔氧化铝分子筛中Ti物种具有较高的分散度．     

Comparison of room-temperature multiferroics in Bi4Fe2TiO12 film and bulk

It was reported that both dielectricity and magnetism at room temperature were appreciably improved in Bi₄Fe₂TiO₁₂ film compared with Bi₄Fe₂TiO₁₂ bulk. X-ray diffraction profiles reveal similar crystalline nature and random orientation of the two, but X-ray photoelectron spectroscopy (XPS) experiments indicate that it is 1.4 eV lower binding energy of core-state O1s in the film relative to that of the bulk, so the improvement of multiferroics in the film is attributed to oxygen vacancies and high fraction of interface. The results have promising applications in multifunctional integrated devices.     

Simulation and experiment of vortex transport properties in a Type Ⅱ superconductor with grain boundary

We firstly described a simulation model to investigate the influence of grain boundary(GB)on the vortex transport properties in YBCO film.It is found that the size of inhomogeneous area caused by GB as well as the average velocity in transverse and longitudinal directions shows an angular dependence when the angle between the GB and the sample edge varies.We have also studied the impact of magnetic field intensity on dynamic behavior of vortex lattice and found that a lower vortex density makes it difficult for the vortex lattice to transfer from pinning state to flow state.As the magnetic field is decreased beyond a critical value,sharp jumps and strong fluctuations were observed in the I-V curve.Finally,we conducted measurements on a thin film YBa2Cu3O7 with an individual artificial grain boundary to support the simulation process.     

射频磁控溅射制备类金刚石薄膜

采用射频磁控溅射法在Si和Ti合金基体上沉积出类金刚石(DLC)薄膜.利用拉曼光谱仪、划痕仪和扫描电子显微镜分析了DLC薄膜的结构、膜基附着力和表面形貌.结果表明:射频磁控溅射法能够制备出表面平整、结构致密的DLC薄膜;同时基体材料的不同不会影响DLC薄膜的键合结构,Si基体上涂层附着力为30N,Ti基体上膜基结合力大于40 N.     

Theoretical calculation and experimental study of influence of oxygen vacancy on the electronic structure and hemocompatibility of rutile TiO2

In this work, the relationship between electronic structure and hemocompatibility of oxygen deficient rutile TiO_2?x was studied by both theoretical calculation and experimental study. Based on the local density functional theory, first-principals method was performed to calculate the electronic structure of rutile TiO₂ with different oxygen vacancy concentration. In the range of less than 10% of (or equal) physically realistic O vacancy concentration, the band gap of rutile TiO₂ increases with increasing O vacancy concentration, leading the TiO₂ changes from a p-type to an n-type semiconductor. The valance band of TiO₂ is predominated by O 2p orbital, while the conduction band is occupied by Ti 3d orbital for different O vacancy concentration. The O vacancy results in the occupation of electrons at the bottom of conduction band of TiO₂, and the donor density increases with increasing O vacancy concentration. When materials come in contact with blood, the n-type semiconductor feature of oxygen deficient TiO_2?x with the bottom of conduction band occupied by electrons would prevent charge transfer from fibrinogen into the surface of materials, thus inhibiting the aggregation and activation of platelets, therefore improving the hemocompatibility of rutile TiO_2-x .

     

组合法制备Pb（ZrxTi（1-x））O3组分梯度薄膜

在无蒸馏和无惰性气氛保护的条件下,快速制备了用于组合合成Pb(ZrxTi1-x)O3薄膜的前驱溶液PT和PZ。采用组合法在Pt/Ti/SiO2/Si衬底上制备了一系列Pb(ZrxTi1-x)O3组分梯度薄膜。经XRD分析表明,薄膜具有钙钛矿结构,择优取向为(111)。SEM结果显示薄膜厚度在500nm左右。电滞回线的测试表明,下梯度薄膜PZT-654表现出良好的铁电性能,明显优于其它薄膜。PZT-654梯度薄膜的剩余极化强度Pr为38.4μC/cm2,矫顽场Ec为75.0kV/cm,有较大的极化偏移,Poffset为12.9μC/cm2,表现出梯度铁电薄膜的特性。     

Al2O3对3Ti/Si/2C体系自蔓延高温合成Ti3SiC2的影响

以3Ti/Si/2C粉体为原料,通过自蔓延高温合成技术合成了Ti3SiC2材料。研究了Al2O3助剂对自蔓延高温合成Ti3SiC2的影响。研究结果表明,3Ti/Si/2C粉体会发生自蔓延反应,产物的组成相为TiC、Ti3SiC2和Ti5Si3,产物中Ti3SiC2含量约为23%。添加适量的细粒度Al2O3可显著促进反应合成Ti3SiC2,3Ti/Si/2C/0.1Al2O3原料反应后得到的产物中Ti3SiC2含量达64%。     

Preparation and properties of SrBi_(2.2) Ta_2O_9 thin film

1INTRODUCTION Ferroelectricfilmshaveattractedmuchatten tionduetotheirpotentialapplicationsinelectronic devices,suchaspyroelectricinfrareddetectors,opticalswitches,actuators,dynamicrandomac cessmemories(DRAMS)[1,2],andnon volatile randomaccessmemories(NVRAMS)[3,4].Re cently,thereisinterestinthestudyofbismuthlayerstructuredferroelectricmaterialsformemory applications.Inparticular,strontiumbismuthtan tanate(SBT),oneofthebismuthlayerstructuredcompounds,isapromisingcandidateforferroelec t…