Electrochemical oxidation of a textile dye wastewater using a Pt/Ti electrode

Textile dye wastewater (TDW) from a reactive azo dyeing process was treated by an electrochemical oxidation method using Ti/Pt as anode and stainless steel 304 as cathode. Due to the strong oxidizing potential of the chemicals produced (chlorine, oxygen, hydroxyl radicals and other oxidants) when the wastewater was passed through the electrolytic cell the organic pollutants were oxidized to carbon dioxide and water. A number of experiments were run in a batch, laboratory-scale, pilot-plant, and the results are reported here according to residence time and initial addition of HCl in raw wastewater. When of 2 ml of HCl 36% were added and after 18 min of electrolysis at 0.89 A/cm(2), chemical oxygen demand (COD) was reduced by 86%, biochemical oxygen demand (BOD(5)) was reduced by 71%, ADMI color units were reduced by 100%, and TKN was reduced by 35%. The biodegradability of the wastewater was improved because the COD/BOD ratio decreased from 2.16 to 1.52. At the same time the efficiency of the electrode was about 170 g h(-1) A(-1) m(-2). and the mean energy consumption was 21 kW h/kg of COD. These results indicate that this electrolytic method could be used for effective TDW oxidation or as a feasible detoxification and color removal pretreatment stage for biological post treatment.     

RF sputtered PLZT thin film on Pt/Ti electrode

PLZT (7.5/65/35) thin films were deposited by rf magnetron sputtering on single crystal Si substrates using an oxide sintered target with excess PbO. The effects of postannealing and bottom Pt/Ti electrodes on the thin film crystal structures and ferroelectric properties were studied. Film deposited at 200°C or below crystallizes to a perovskite phase after annealing treatment at 550°C or above, and the crystal structure depends on the annealing treatment. The best crystal structures and electronic properties were obtained when the thin films were annealed at 600°C to 650°C for 1 h in O₂. For the Pt/Ti two-layer bottom electrode, the thickness of the Ti layer has a dominant effect. When the Ti layer was too thick or too thin, the PLZT thin film structures consist mainly of pyrochlore phases. However, using an appropriate Ti layer thickness, PLZT thin films having good crystal structures and ferroelectric properties can be obtained, with typical remanent polarization value of 220 mC/m² and coercive field strength of 6.5 MV/m     

Low-voltage field emission from silver-modified porous glass

Planar silver layers have been produced on the surface of porous glass (PG) membranes by multiple impregnations with an aqueous AgNO₃ solution, followed by hydrogen reduction of the salt to silver metal. In all cases, electron emission from the surface of the metallized porous glasses is observed above threshold electric fields lower than 2 V/μm. The emittance of the Ag/PG membranes decreases as the amount of silver increases above a nominal monolayer.     

Efficient field emission from tetrapod-like zinc oxide nanoneedles

Tetrapod-like zinc oxide (ZnO) nanoneedles were fabricated using a simple and economical method of rapid heating high purity zinc powders at 900 °C. No catalyst and vacuum were employed in the experiment. Field-emission measurements showed that the turn-on field of the synthesized tetrapod-like ZnO nanoneedles was as low as 1.8 V/μm at the emission current density of 1.0 μA/cm² and the emission current density reached 1.0 mA/cm² under an applied field of about 3.9 V/μm. The low turn-on field, high emission current density, and good electron emission stability make the ZnO nanoneedles one of the promising candidates for field-emission displays.     

Design and fabrication of multilayer actuator using floating electrode

PZT (lead zirconate titanate) multilayer actuators were of interest due to their small volume, fast response, low power consumption and low driving voltage. But this multilayer actuator had some problems. However, due to internal stress around electrodes, crack and delamination were very important issues. Around the edge of conventional inter-digital electrodes, non-uniform electric field generates the stress concentration, which causes the ceramic crack and delamination. The internal stress distribution in multilayer actuator was analysed by a numerical simulation. And by using float electrode, multilayer actuator was manufactured to decrease internal stress concentration of inter-digital electrode. The float electrode could suppress the electric field concentration and cracking in the actuator.

Destruction mechanism in multilayer ceramic actuators has been investigated under cyclic electric fields. Crack propagation has been observed dynamically by using optical microscopy, and the accompanying characteristic of acoustic emission was measured.     

Pt/YSZ电极烧制工艺研究

借助交流阻抗谱测试技术和扫描电镜,研究了Pt/YSZ电极烧制工艺条件对其性能的影响.研究表明,制作Pt/YSZ电极时烧结温度越高,电极阻抗越大,氧传感器响应越慢,但O2的电极还原反应速率控制步骤(＞600℃,吸附氧原子Oatm在Pt表面向YSZ的扩散过程;＜500℃,气相O2分子在Pt/YSZ界面附近的解离吸附过程)未发生变化;电极烧结的升/降温速率对电极阻抗和氧传感器响应时间有显著影响,降温速率增大还会使电极反应激活能发生突变(＞600℃,激活能由169kJ/mol突然增至(217±4)kJ/mol);当Pt/YSZ电极工作温度＜500℃时,其最优烧制工艺为烧结温度700℃,升/降温速率0.5～1℃/min.     

Reactive ion etching of Pt electrode using O2-based plasma

We have studied the reactive ion etching (RIE) of Pt electrode using O₂ plasma with additional gases. Dual frequency RIE tool was used to obtain a high-energy ion bombardment. We have investigated the Pt etching profile using O₂/HBr/Ar plasma. We reveal that there is a optimal gas flow ratio for attaining the node separation of Pt electrodes at small critical-dimension (CD) pattern.     

Nanostructure and chemical characterisation of individual NiFe/Pt multilayer nanowires

NiFe/Pt multilayer nanowires have been successfully fabricated by pulse electrodeposition into the channels of porous anodic aluminum oxide (AAO) templates, and characterized at the nanoscale. Individual nanowires have uniform structure and regular periodicity. The NiFe and Pt layers are polycrystalline, with random orientation fcc lattice structure crystallites and grain sizes 3-10 nm, and the average layer growth rate is 30 nm/s for NiFe and 4 nm/s for Pt. Nanoscale chemical analysis of individual NiFe/Pt nanowires by EDX and EELS shows that they contain alternating NiFe and Pt layers, with a small approximately 1% inclusion of Pt in the NiFe layer due to electrochemical co-deposition.     

Efficient field emission from vertically grown planar ZnO nanowalls on an ITO-glass substrate

Vertically grown planar ZnO nanowalls, with typical dimensions of 40-80?nm thickness and several micrometers wide, were electrodeposited on an indium-tin-oxide (ITO)-glass substrate at 70?°C. X-ray photoelectron spectroscopy (XPS) studies reveal that the nanowalls consist of ZnO covered with a Zn(OH)(2) overlayer. An x-ray diffraction (XRD) study shows that these nanowalls have the wurtzite structure and are highly crystalline. The corresponding Raman and photoluminescence spectra further indicate the presence of oxygen deficiency. These ZnO nanowalls exhibit excellent field emission performance, with not only a considerably lower turn-on field of 3.6?V?μm(-1) (at 0.1?μA?cm(-2)) but also a higher current density of 0.34?mA?cm(-2) at 6.6?V?μm(-1) than most ZnO nanowires and other one-dimensional nanostructures reported to date.     

Electrochemical treatment in relation to pH of domestic wastewater using Ti/Pt electrodes

This paper describes an electrochemical treatment of domestic wastewater (DW) using 0.8% (w/v) sodium chloride as electrolyte. In this technique, DW was passed through an electrolytic cell using Ti/Pt as anode and Stainless Steel 304 as cathode. Due to the strong oxidizing potential of the chemicals produced (chlorine, oxygen, hydroxyl radicals and other oxidants), the organic pollutants and nutrients (organic nitrogen, phosphorous) were wet oxidized to carbon dioxide, and nitrogen as well as phosphorous was precipitated as Ca(3)(PO(4))(2). Experiments were run in a continuous, laboratory-scale, pilot plant, at 40 degrees C and the efficiency of oxidation was studied in relation to pH. It was found that in alkaline conditions the electrolysis was more efficient. At pH 9, NaCl concentration 0.8% (w/v), current density 0.075 A/cm(2) and for 1h of electrolysis, COD was reduced by 89%, volatile suspended solids (VSS) by 90%, ammonia nitrogen by 82% and total phosphorous by 98%. The efficiency of electrolysis went up to 35 g COD(r)/(hm(2)A) and the energy consumption to 12.4 kWh/kg COD(r). It is concluded that the application of electrolytic oxidation of DW is more advantageous compared to conventional biological treatment especially for small works.     

Cu丝上沉积Ti/TiN多层膜的研究

铜丝可用于尿毒症患者腹膜透析置管术中的替代导丝。为了减少或消除铜离子对生物组织的损害,增加铜丝表面的生物相容性,同时又保持铜丝较好的塑性变形能力,本文采用电弧离子镀工艺在铜丝上沉积Ti/TiN多层膜。研究结果显示,镀膜铜丝表面光亮呈金黄色。沉积膜有明显的周期性层状特征,TiN相和金属Ti相周期性交替分布。其中,TiN相具有(111)晶面择优取向。沉积膜与铜丝结合良好,弯曲时镀膜铜丝没有出现微裂纹和膜脱落现象。室温消毒液浸泡和高温蒸汽消毒处理后,镀膜铜丝表面没有变化。腹膜透析置管术中使用镀膜铜丝,患者腹膜炎发生率明显降低,镀制Ti/TiN多层膜的铜丝适合应用于腹膜透析手术。     

钴钝化多孔硅的制备及其场发射特性研究

采用化学染色腐蚀法在Co(NO3)2 和HF酸组成的腐蚀液中制备了钴钝化多孔硅,其表面形貌由垂直于表面分布的尺度为0.5~1.5μm 的硅尖组成,部分硅尖顶端还有0.1~0.5μm的圆形孔洞,硅尖的面密度约为1.0×108 个/cm2,多孔硅层厚度约为2μm。XPS分析结果表明,钴原子仅存在于多孔硅表面非常薄的一层内。其场发射具有较好的可靠性和可重复性,开启场强一般为2.3V/μm 左右,场强为5.4V/μm时,亮点均匀而且密集,发射电流密度达到30μA/cm2 左右。     

The magnetic and magnetooptical properties of Fe/Ti, Zr, Pt and Fe/Ti, Zr, Pt/Fe thin-film magnetic structures

The results of investigation of the magnetic and magnetooptical properties of two-layer Fe/Ti, Zr, Pt and three-layer Fe/Ti, Zr, Pt/Fe thin-film magnetic structures are presented. The nonmagnetic layer exhibits a strong effect on the magnetic properties of samples. The magnitude of the saturation field of three-layer magnetic structures oscillates as a function of thickness of the nonmagnetic layer; the period of this oscillation depends on the thickness of the Fe layer. The Pt layer strongly affects the spectral dependences of the equatorial Kerr effect in the structures investigated.     

Ti/TiO2多层膜的光电性能研究

用真空蒸发和自然氧化法在玻璃基底上制备了Ti／TiO2多层膜，并检测了薄膜的光电性能。电性能检测表明Ti／TiO2多层膜存在类负阻效应，多层膜的层间的类负阻效应比表面的更明显，薄膜的层间电阻率高于表面电阻率；用分光光度计测得试样退火前后的透射谱；用X射线衍射仪和扫描电镜检测了Ti／TiO2多层膜的晶体结构和表面形貌。     

VOx/TiOx/Ti多层薄膜的制备工艺与内耗研究

用磁控反应溅射法在玻璃和镅片衬底上制备Vox/TiOx/Ti多层薄膜.用X射线衍射(XRD)、QJ31单臂电桥、薄膜内耗仪等测试了薄膜的晶体结构、电阻、内耗.分别进行了薄膜的制备工艺与内耗研究.测试分析结果表明:试样的晶体结构、电阻-温度曲线、杨氏模量的突变均表明多层薄膜在66℃左右发生相变.样品的电阻温度系数为-4.35%/℃.并且真空退火有利于二氧化钒相生成.     

Field emission from the structure of well-aligned TiO2/Ti nanotube arrays

Well-aligned TiO₂/Ti nanotube arrays were synthesized by anodic oxidation of titanium foil in 0.5 wt.% HF in various anodization voltages. The images of filed emission scanning electron microscopy indicate that the nanotubes structure parameters, such as diameter, wall thickness and density, can be controlled by adjusting the anodization voltage. The peaks at 25.3° and 48.0° of X-ray diffraction pattern illuminate that the TiO₂ nanotube arrays annealed at 500 °C are mainly in anatase phase. The filed emission (FE) properties of the samples were investigated. A turn-on electric field 7.8 V/µm, a field enhancement factors approximately 870 and a highest FE current density 3.4 mA/cm² were obtained. The emission current (2.3 mA/cm² at 18.8 V/µm) was quite stable within 480 min. The results show that the FE properties of TiO₂/Ti have much relation to the structure parameters.     

Research of optical and structural properties in Cu/Ti multilayer films

The Cu/Ti multilayer (ML) films were deposited on Si(1 0 0) and Si(1 1 1) substrate with a series of pair layers with Vanguard sputtering system. The influences of periodic number and substrate structure on UV-reflectivity of Cu/Ti superlattice films were investigated carefully. The result shows that the Cu/Ti ML films have clear layer-structure. The ML films deposited on Si(1 0 0) and Si(1 1 1) have UV-reflectivity of about 90% and 67% at 200 nm, respectively, but they have lower soft X-ray reflectivity of about 1.9% at 13.04 nm in terms of wavelength, with near normal incidence of 5°. The transmission microscope image indicates that the fabricated Cu/Ti ML films have superlattice structure.     

Deflection of wafers and cantilevers with Pt/LNO/PZT/LNO/Pt/Ti/SiO2 multilayered structure

The present paper describes a Pt/LNO/PZT/LNO/Pt/Ti/SiO₂ multilayers deposited on 4-inch Si wafers. We have evaluated the variation of the deflection of the Si wafers with deposition of each of the thin films. The deposition of the multilayers has resulted in downward deflection (center is higher than edge) of the Si wafers. The multilayers have been also deposited onto SOI wafers and fabricated into piezoelectric micro cantilevers through MEMS bulk micromachining. The micro cantilevers have shown the upward deflection. We have characterized the ferroelectric and piezoelectric properties of the PZT thin films through electrical tests of the micro cantilevers. The dielectric constant, saturation polarization, remanent polarization and coercive field were measured to be 1050, 31.3 μC/cm², 9.1 μC/cm² and 21 kV/cm, respectively. The transverse piezoelectric constant, d₃₁, was measured to be − 110 pm/V from the DC response of the micro cantilevers.     

Imaging the domain pattern of the canted magnetization state in Co/Pt multilayer films

The exact magnetization pattern of magnetic films close to a spin-reorientation transition is difficult to analyze due to the intrinsically three-dimensional (3d) variation of the orientation of the local magnetization. We present a technique how this can be performed, based on the analysis of high quality 2d polarization maps from a single scanning electron microscope with polarization analysis (SEMPA) measurement with tilted sample. The key tool is the statistical distribution of all occurring polarization doublets, visualized in a 2d histogram plot. From the shape of the distribution the type of transition—canted-phase, or coexisting phases—can be inferred. For the canted-phase state, the canting angle can be accurately determined from geometrical considerations. With help of the histogram the image data can be analyzed and the three components of the magnetization can be calculated for most points of the image. For a Co/Pt multilayer film we found a cone state. The magnetization forms a complex pattern consisting of out-of-plane domains while the in-plane magnetization shows a maze pattern.