电流密度对AlSi7Mg0.3铝合金微弧氧化陶瓷层性能的影响

以采用微弧氧化技术在AlSi7Mg0.3铝合金表面制备的陶瓷层为研究对象,利用XRD和SEM等手段分析了陶瓷层的相组成及表面形貌,探讨了电流密度对成膜速率、膜层结构的影响,借助拉伸实验研究了陶瓷膜与基体的结合强度.研究结果表明:电流密度过大会使陶瓷层成膜速率加快、表面质量下降、结合力降低;微弧氧化陶瓷层主要由γ-Al_2O_3、α-Al_2O_3和少量Al_2(SiO_4)O组成,电流密度的变化会导致陶瓷层内γ-Al_2O_3和α-Al_2O_3的含量变化,在一定范围内,电流密度越高,γ-Al_2O_3的含量越多,陶瓷层性能越好;陶瓷层界面结合强度随着电流密度增加而增加,但过大的电流密度反而导致界面结合强度减小.     

γ-Al_2O_3球和蜂窝陶瓷负载Fe_2O_3臭氧氧化降解丙烯酸废水的研究

以γ-Al_2O_3颗粒和蜂窝陶瓷为载体,采用硝酸盐浸渍法制备了负载Fe_2O_3的两种催化剂,Fe_2O_3/γ-Al_2O_3催化剂和Fe_2O_3/蜂窝陶瓷催化剂.分别测试了蜂窝陶瓷、Fe_2O_3/蜂窝陶瓷催化剂和γ-Al_2O_3、Fe_2O_3/γ-Al_2O_3催化剂的比表面积;以丙烯酸废水中的丙烯酸作为目标污染物,分别对比了单独臭氧氧化、Fe_2O_3/γ-Al_2O_3催化剂和Fe_2O_3/蜂窝陶瓷催化对丙烯酸的降解效果.结果表明,Fe_2O_3/蜂窝陶瓷和Fe_2O_3/γ-Al_2O_3催化剂对丙烯酸的COD的去除率分别为93.4%和83.1%,比单独臭氧氧化时的COD去除率69.9%有大幅度的提高;Fe_2O_3/蜂窝陶瓷和Fe_2O_3/γ-Al_2O_3催化剂对丙烯酸的TOC的去除率分别为82.7%和75.2%,与单独臭氧氧化时TOC去除率相比,分别提高了31%和24%.     

(Y,Ce)TZP-Al_2O_3陶瓷显微组织对力学性能及热稳定性的影响

研究了(Y、Ce)TZP-Al_2O_3陶瓷的显微组织对其力学性能和热稳定性的影响。结果表明,试样表面t-ZrO_2失稳相变是造成低温时效和热循环条件下材料强度下降的主要原因。添加CeO_2稳定剂和Al_2O_3相可较大幅度地提高(Y,Ce)TZP-Al_2O_3陶瓷的力学性能及热稳定性。1550℃烧结晶粒尺寸0.9μm,其力学性能和热稳定性综合性能优越。     

热压烧结制备Mg稳定Na-β"-Al_2O_3电解质陶瓷及其性能

分别以α-Al_2O_3,(α+θ)-Al_2O_3和γ-Al OOH为铝源,采用固相法合成了Mg稳定的β"-Al_2O_3粉体,通过比较各产物中β"相的含量,确定了最佳铝源。以最佳铝源制备的β"-Al_2O_3粉体为原料,进一步通过热压烧结工艺制备了固体电解质陶瓷片,研究了烧结温度对烧结体中的β"相含量、断面形貌、相对致密度以及离子电导率等的影响。借助XRD,TG-DSC,FESEM和EIS对样品进行了测试表征。结果表明:以γ-Al OOH为铝源所制备粉体产物的纯度最高(β"相含量高达99.8%),且能在较宽的温度范围内保持稳定(1 115～1 600℃),而热压烧结温度同时影响陶瓷片中β"相的含量和相对致密度。当烧结压力为30 MPa,烧结温度为1 450℃时,陶瓷片中β"-Al_2O_3的含量高达95%,此时的陶瓷片结构致密、均匀,室温离子电导率约为3.8×10~(-4)S·cm~(-1)。     

部分稳定氧化锆结构陶瓷的应用研究通过鉴定

我院承担江苏省科委下达的“部分稳定氧化锆结构陶瓷的应用研究”课题,经过课题组努力,所研制的CeO_2-ZrO_2-Al_2O_3、Y_2O_3-ZrO_2-Al_2O_3-TiC基复合陶瓷粉体及材料制备技术,具有较高的实用价值,粉体性能指标达到目前国际先进水平.经生产试用,研制成功的陶瓷拉丝模使用寿命是硬质合金模的2.94倍,陶瓷热挤压模使用寿命比热作模具钢3Cr_2W8V模具提高三倍,处于国内领先水平。     

溶胶-凝胶+机械球磨法制备纳米α-Al_2O_3/Ni复合粉体

采用溶胶-凝胶+机械球磨法制备了纳米α-Al_2O_3/Ni复合粉体,研究了α-Al_2O_3/Ni复合粉体的微观结构及其在球磨过程中的结构演变和形貌演变,探讨了复合粉体的球磨细化机理.结果表明:通过溶胶-凝胶法制备的复合胶体经1 200℃煅烧2h后可获得晶体结构完整的α-Al_2O_3/Ni复合粉体,粉体微观结构为脆性α-Al_2O_3纳米颗粒包覆于Ni颗粒表面的壳核型球形结构.在机械球磨过程中,α-Al_2O_3/Ni复合粉体的颗粒形貌经历了由球状到层片状再到类球状的变化,球磨20h时复合粉体的细化效果最佳.2种物相的晶粒尺寸在球磨初期细化速率很快,纳米晶α-Al_2O_3在球磨5h时平均晶粒尺寸迅速减小为27nm,球磨20h后出现部分非晶化;Ni晶粒尺寸则在5、10h时减小至22、17nm,球磨10h以后晶粒尺寸趋于稳定.复合粉体经球磨20h后可获得α-Al_2O_3弥散分布于Ni颗粒中的超级分散体系.     

γ-Al_2O_3催化臭氧深度处理蔗渣制浆废水

对单独臭氧氧化处理制浆废水与γ-Al_2O_3催化臭氧深度处理制浆废水进行了对比研究,结果表明:γ-Al_2O_3对臭氧具有一定的催化作用,能够显著提高废水的COD_(Cr)去除率;随着主要影响因素pH值、反应温度、臭氧浓度和催化剂用量的增加,COD_(Cr)去除率均先增大后降低;同时,γ-Al_2O_3催化臭氧还能够有效地降低废水中AOX(可吸附有机卤化物)的含量;实验室条件下,处理30 min,AOX去除率可达80.4%.文中还采用扫描电镜对再生前后的γ-Al_2O_3、采用UV和GC-MS对处理前后的废水进行分析,结果显示,γ-Al_2O_3催化臭氧能大幅降低废水中的有机物种类和含量,并且能较好地降解难生物降解的有机物,其作为催化剂具有良好的稳定性,重复使用8次后,经过焙烧再生,仍可保持88.5%的催化活性.     

碱金属氯化物在载体γ—Al2O3上存在状态的研究

本文用X-射线衍射、透射电子显微镜、选区电子衍射研究了LiCl/γ-Al_2O_3、KCl/γ-Al_2O_3、CsCl/γ-Al_2O_3诸体系,结果表明,加热KCl与γ-Al_2O_3或者CsCl与γ-Al_2O_3的混合物,KCl、CsCl能在γ-Al_2O_3表面呈单层分散,它们的最大单层分散量分别为0.051gKCl/100m~2γ-Al_2O_3,0.082gCsCl/100m~2γ-Al_2O_3,而加热LiCl和γ-Al_2O_3混合物时,LiCl则和γ-Al_2O_3反应生成体相化合物Li_2O·5Al_2O_3。     

利用合成渣对钢水脱氮的研究

试验研究了CaO-TiO_2-Al_2O_3,CaO-Al_2O_3-SiO_2 及CaO-B_2O_3-SiO_2渣系中TiO_2,Al_2O_3。及B_2O_3 含量对钢水脱氮率的影响。在三个渣系中,随着 TiO_2,Al_2O_3 及B_2O_3 含量的变化,脱氮率有一最大值,其脱氮率可达 55％—65％。钢和渣中氧位愈低,脱氮率愈高。增加渣中碳、铅及钢中铝的含量,可以提高合成渣脱氮效果。     

机械诱发自蔓延反应合成Ti_3AlC_2的机理研究

以3Ti／Al／2C粉体为原料,采用机械合金化的方法以合成Ti3AlC2材料。研究结果表明,在机械合金化过程中诱发自蔓延反应,反应会产生大量坚硬的小块体颗粒,大小约为0．2-11mm。粉体的组成相为TiC、Ti3AlC2、Ti2AlC,而块体仅含有TiC和Ti3AlC2。获得的粉体和块体产物中Ti3AlC2含量分别约为63wt％和84．8wt％。提出了一个机械诱发自蔓延反应合成Ti3AlC2的反应机制,即Ti3AlC2是从固相TiC与Ti-Al液相中形核并长大。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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