EIS analysis of hydrophobic and hydrophilicTiO2 film

Titanium oxide films were formed on metallic titanium substrates by employing a thermal treatment at 800 °C under air atmosphere. Component and microstructure of the oxide films were characterized by XRD and SEM method. Water contact angles on titanium oxide film surface were measured in both dark and sunlight illumination condition. Corrosion tests were carried in seawater solution under different illuminate conditions. Electrochemical impedance spectroscopy (EIS) techniques were used to study the changes on TiO₂ film. Results indicated that: hydrophilic TiO₂ film suffered a severe photo-corrosion effect in seawater due to their semiconductor properties under sunlight condition, but the hydrophobic TiO₂ film under dark condition exhibited a good corrosion resistance.     

微束等离子弧熔化沉积TiAl/Ti2AlNb梯度材料的组织与相变

采用微束弧热态焊技术熔化沉积Ti₂AlNb合金丝材,在TiAl基合金环状试样上制备出Ti₂AlNb基合金梯度材料。利用金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)方法及显微硬度测试,对沉积态TiAl/Ti₂AlNb梯度材料的显微组织、相组成和显微硬度进行了分析。结果表明：微束弧热态焊技术熔化沉积的Ti₂AlNb基合金组织由β相、O相和α₂相组成,并且随着距离母材距离的增加,梯度材料呈现出γ+α₂/γ→β(固溶体)+O→β₂+O+α₂(魏氏组织)→β(固溶体)+O的相变趋势。梯度材料的硬度呈现出波浪式的分布。另外结合各元素对组织稳定性的影响,以及微束等离子技术所具有的特殊热循环和热积累效应,对梯度材料在微束等离子沉积过程中的相变规律进行了解释。     

镁盐在反应染料废水治理中的应用研究

以含有活性艳红、活性艳黄、活性艳蓝等多种反应染料的高浓度染料废水为试验对象,在反应时间、ｐＨ 值、镁盐加入量、Ｃａ（ＯＨ）２ 的协同影响、与其他絮凝剂比较等几方面系统地研究了镁盐在反应染料废水ＣＯＤ 去除及脱色中的应用。结果表明：对于反应染料废水,镁盐对其ＣＯＤ 去除及脱色效果优于其他试剂。实验最佳条件为ｐＨ＞ １０．５,反应时间０．５ｈ。Ｃａ（ＯＨ）２ 与镁盐吸附处理具有协同作用     

TC4钛合金扩散连接区热变形特性行为研究

以TC4钛合金扩散连接区为研究对象,在变形温度920,950,980,1010 ℃及应变速率0.01,0.1,1,10 s-1的条件下进行热变形试验,研究了变形温度和应变速率对TC4钛合金扩散连接区流变应力和微观组织的影响规律。研究结果表明：TC4钛合金扩散连接区在高温下具有明显的动态软化特征,流变应力随变形温度的升高而降低,随变形速率的提高而增大;高温变形后扩散连接界面消失,随变形温度的增加,等轴α相的体积分数减少,同时伴有短棒状和板条状的次生α相出现,且次生α相的体积分数随应变速率增加逐渐降低;当变形温度达到1010 ℃时,出现马氏体α′相;以双曲正弦形式修正的Arrhenius方程为基础,建立了TC4钛合金扩散连接区双曲正弦本构方程以及热加工图,确定TC4钛合金扩散连接区的最佳变形温度为920~950 ℃,变形速率为0.01~0.1 s-1。     

以碱土金属为助剂的 CuO/CeO2水煤气变换催化剂的催化性能

采用共沉淀法制备了系列CuO/CeO_2-MO(M=Mg、Ca、Sr和Ba)催化剂,通过X射线粉末衍射、M_2物理吸附、N_2O选择性化学吸附、H_2程序升温还原和循环伏安法等手段对催化剂的物化性能进行表征,考察了富氢条件下水煤气变换反应中碱土金属氧化物作为助剂对CuO/CeO_2催化剂性能的影响。结果表明,BaO作为助剂可降低载体CeO_2和CuO的晶粒度,有效增大催化剂的比表面积,提高铜组分的表面分散度,并有利于更多与载体表面氧空位有强相互作用的CuO物种的形成,从而获得较高的催化活性。MgO、CaO和SrO的添加对催化剂活性影响较小。关联活性数据和结构表征结果,推断CuO/CeO_2催化剂在水煤气变换反应中的有效活性位是与载体CeO_2表面氧空位强相互作用的单质Cu。     

An improved strategy to synthesize graphite oxide with controllable interlayer spacing as coatings for anticorrosion application

A facile method to synthesize nanoscale graphene oxide (GO) with controllable interlayer spacing was carried out using two-step oxidation process and much less acid to improve the efficiency of the oxidation. The X-ray diffraction results demonstrated that GO had been successfully prepared from graphite because of disappearance of characteristic peaks of pristine graphite at about 2θ = 26.5° along with appearance of a sharp major peak of GO at about 2θ = 9.4°. The increased basal spacing d₀₀₁ of as-prepared GO could reach as high as 9.39 Å, suggesting higher degree of oxidation than that prepared by the classical Hummers' synthesis, and characterization results from Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy further confirmed this conclusion. The influence of GO on anti-corrosion performance of nanocomposite coatings composited with the 2,5-dimethoxyaniline (DMA) conductive polymer was examined via potentiodynamic polarization curve tests in 3.5 wt% NaCl aqueous solution. The results demonstrated that the incorporation of GO significantly decreased the corrosion current density (i_corr = 2.62 μA/cm²) in the case of GO-PDMA coating, reflecting excellent physical isolation of GO and its synergistic effect with PDMA against the infiltration of water and corrosive electrolyte.     

High nitrogen carbon material with rich defects as a highly efficient metal-free catalyst for excellent catalytic performance of acetylene hydrochlorination

In this work,we developed a simple strategy to synthesize a carbon material with high nitrogen and rich carbon defects.Our approach polymerized diaminopyridine(DAP) and ammonium persulfate(APS).Following a range of different temperature pyrolysis approaches,the resulting rough surface was shown to exhibit edge defects due to N-doping on graphite carbon.A series of catalysts were evaluated using a variety of characterization techniques and tested for catalytic performance.The catalytic performance of the N-doped carbon material enhanced alongside an increment in carbon defects.The NC-800 catalyst exhibited outstanding catalytic activity and stability in acetylene hydrochlorination(C_2 H_2 GHSV=30 h~(-1),at 220℃,the acetylene conversion rate was 98%),with its stability reaching up to 450 h.Due to NC-800 having a nitrogen content of up to 13.46%,it had the largest specific surface area and a high defect amount,as well as strong C_2 H_2 and HCl adsorption.NC-800 has excellent catalytic activity and stability to reflect its unlimited potential as a carbon material.     

Facile fabrication of ordered assembled TiO2/g-C3N4 nanosheets with enhanced photocatalytic activity

A series of assembled porous TiO₂/g-C₃N₄ (TC) powders composed of spherical nanoparticles were synthesized by controlling the molar ratio of urea to tetrabutyl titanate (TBOT) in a facile hydrothermal process. A nanosheets-constructed hierarchical structure was obtained at the molar ratio of urea to TBOT of 10:1, which possessed uniform mesopores with bimodal distribution (0.5–1.5 nm and 2–20 nm) and interconnected macropores between TC nanosheets. The specific surface area achieved 98.4 m² g^?1. X-ray diffraction (XRD) patterns and high resolution transmission electron microscope (HRTEM) analysis proved that the nanosheets are made of overlapping TC nanocomposite. Photoluminescence (PL) spectra results illustrated that a well-defined hierarchical porous structure is particularly desired for the low recombination rate of carriers. Further, the TC-decorated carbon fiber (CF) cloth was obtained based on the nanosheets assembled hierarchical structure, which showed more outstanding photocatalytic behavior with high degradation capability for Rhodamine B (RhB) (99.9%) and tetracycline hydrochloride (89.8%) at 60 min by 500 W Xe lamp irradiation. After five consecutive cycles, the degradation efficiencies of TC/CF cloth for both RhB and tetracycline hydrochloride all remained above 90% of the initial value.     

Fabrication of barium titanate ceramics via digital light processing 3D printing by using high refractive index monomer

A digital light processing (DLP) technology has been developed for 3D printing lead-free barium titanate (BTO) piezoelectric ceramics. By comparing the curing and rheological properties of slurries with different photosensitive monomer, a high refractive index monomer acryloyl morpholine (ACMO) was chosen, and a design and preparation method of BTO slurry with high solid content, low viscosity and high curing ability was proposed. By further selecting the printing parameters, the single-layer exposure time was reduced and the forming efficiency has been greatly improved. Sintered specimens were obtained after a nitrogen-air double-step debinding and furnace sintering process, and the BTO ceramics fabricated with 80 wt% slurry shows the highest relative density (95.32 %) and piezoelectric constant (168.1 pC/N). Furthermore, complex-structured BTO ceramics were prepared, impregnated by epoxy resin and finally assembly made into hydrophones, which has significance for the future design and manufacture of piezoelectric ceramic-based composites that used in functional devices.     

电力市场环境下的发电容量充裕性（一）单一能量市场情形

能否完全依靠单一能量市场来确保发电容量充裕性是一个存在广泛争论的重要问题。研究了在完全竞争的单一能量市场中的发电容量充裕性问题,建立了相关的理论分析模型,研究结果表明没有足够的理论依据证明这种市场模式能够确保发电容量充裕性;根据对采用这种市场模式的实际电力市场的运营情况分析,表明了单一能量市场在引导充裕发电投资方面确实存在问题。理想条件下的理论模型分析和现实情况下的影响因素讨论均表明,单一能量市场模式难以确保发电容量的充裕性。这些研究有助于理解和把握电力市场环境下发电容量充裕性问题的基本特征。