在O2和NO存在下Ir催化氧化黑烟的研究

模拟柴油机尾气中O2和NO的氛围,研究了以Ir为基础的催化剂对黑烟的催化氧化。与Pt/SiO2比较,Ir/SiO2对黑烟氧化有其相似的催化活性,但有更高的CO选择性。通过测定Ir含量对催化活性和CO选择性的影响,发现在研究的范围内(0到5%),随着Ir含量的增加,催化活性增加,CO选择性降低。此外,测定了氧化物载体对催化活性及CO选择性的影响,得到了催化活性顺序为Ir/ZSM-5>Ir/SiO2>Ir/γ-Al2O3,CO选择性顺序为Ir/ZSM-5相似文献   

K2O对Pt／γ—A12O3上CO选择性氧化反应的助催效应

采用等体积浸渍法制备Pt／γ—Al2O3催化剂，通过添加K2O考察其对改善富氢气氛中CO选择性氧化性能的影响。结果表明，当加入K2O的质量分数为0．034，且采取在负载Pt后再添加的方式时，可显著改善催化剂的低温活性，在120℃时CO转化率可达90％。降低富氢气中CO浓度有助于提高CO转化率。O2／CO增加也可提高CO转化率，但O2／CO的增加并不能提高CO氧化的选择性。为了同时得到CO高转化率和CO氧化高选择性，O2／CO(V：V)为1．0～1．8。用BET、XRD和CO—TPD等表征方法说明了K2O的助催效应。     

不同载体和前驱体对钴基催化剂浆相费托合成性能的影响

以SiO2和γ-Al2O3为载体，以硝酸钴、醋酸钻和氯化钴为前驱体，利用浸渍法制备出钻基细粒子催化剂。用X射线衍射、程序升温还原、比表面测试等技术考察了钴基催化剂的结构和还原性能，分析了不同载体和前驱体对浆相费托反应性能的影响。结果表明，SiO2载体上钴物种的分散度和还原度均高于γ-Al2O3载体，因而Co／γ-Al2O3催化剂的活性最差，CO转化率远低于Co／SiO2催化剂。不同钴前驱体所制备的Co／SiO2催化剂钴物种的分散度和还原度有很大的差别，其相应的Co／SiO2催化剂的浆相费托活性顺序由大到小依次为：Co(NO3)2，Co(NO3)2 Co(CH3CO2)2，Co(CH3CO2)2，CoCl2。     

复合载体对Ni基甲烷化催化剂性能的影响

通过对Ni基甲烷化催化剂的不同复合载体进行研究发现:与纯γ-Al2O3载体相比,由ZrO2,MgO,SiO2,TiO2与γ-Al2O3复合形成的复合载体,均对CO甲烷化催化性能有一定影响,而以γ-Al2O3/MgO,γ-Al2O3/SiO2两种复合型载体对CO甲烷化活性和选择性促进最为明显。同时,γ-Al2O3/MgO复合载体表现出良好的热稳定性,催化剂活性衰减小。     

助剂及载体对MoO3,MxOy/SiO2催化剂性质及甲烷部分氧化性能的影响

在常压下 ,以氧气为氧化剂 ,用两种不同制法的载体分别制备催化剂 (MoO3 ·MxOy/SiO2 ) ,用于甲烷部分氧化反应 ,对比结果表明用醇盐法所制SiO2 (ZSiO2 )做成的催化剂比用市售SiO2 (QSiO2 )做成的催化剂反应活性和选择性好 ,助剂V2 O5加入提高了CH4 转化率和CO2 ,CO选择性 ,降低了HCHO产率和选择性 ,B2 O3 加入提高了CH4 转化率 ,HCHO产率和其选择性 ,降低了CO2 ,CO选择性 ,TPR结果表明载体ZSiO3 的应用减少了载体表面弱酸性位 ,但助剂V2 O5和B2 O3 的加入使MoO3 与ZSiO2 发生了不同的相互作用 ,从而影响了催化剂表面的活性氧物种 ;NH3 TPD结果表明载体ZSiO3 的应用及助剂B2 O3 的加入增加了催化剂表面弱酸性位     

负载Pt催化剂在卤代硝基苯氢化反应中的催化性能研究

考察了常压、303K反应条件下，γ—Al2O3、TiO2和ZrO2上负载的铂催化剂在卤代硝基苯的氢化反应中的催化性能，同时考察了过渡金属(Cr，Mn，Fe，Co，Ni和Cu)改性Pt/ZrO2的催化性能．不同负载的铂催化剂加氢活性次序为：Pt／TiO2＞Pt／γ—Al2O3＞Pt/ZrO2，相应的对氯苯胺(p—CAN)选择性次序为：Pt／TiO2＞Pt／ZrO2＞Pt／γ—Al2O3．KBH4处理过的催化剂显示了较高的催化活性．Mn、Fe和Co的引入同时提高了Pt／ZrO2催化剂的催化活性和p—CAN选择性．PtNi／ZrO2催化剂随着Ni含量的增加，催化活性降低，但产物p—CAN的选择性都超过99％．     

CO选择性氧化催化剂K—Pt／γ—A12O3催化剂的TPD／TPR研究

用TPD和TPR技术考察了K的添加对CO选择性氧化催化剂Pt／γ-A12O3的表面吸附性能及还原性能的影响，结合催化剂的活性进行了讨论．结果表明，添加适量K2O有助于增加弱吸附态CO的数量，并影响Pt的还原过程，使Pt变得难于还原．当ω(K2O)＝3．4％时，CO的低温脱附量最大，催化剂还原温度最低．同时，120℃时转化率可达到90％以上．     

乙醇-H_2O蒸汽相中合成高硅沸石的研究

在乙醇-H2O混合蒸汽相中,合成高硅ZSM-5、ZSM-35沸石的纯相。研究了SiO2/Al2O3、乙醇/H2O、Na2O/SiO2等因素对合成高硅ZSM-5、ZSM-35沸石的影响。实验证明,乙醇是合成ZSM-35沸石的有效模板剂。     

K2O对Pt/γ-Al2O3上CO选择性氧化反应的助催效应

采用等体积浸渍法制备Pt/γ-Al2O3催化剂,通过添加K2O考察其对改善富氢气氛中CO选择性氧化性能的影响.结果表明,当加入K2O的质量分数为0.034,且采取在负载Pt后再添加的方式时,可显著改善催化剂的低温活性,在120 °C时CO转化率可达90%.降低富氢气中CO浓度有助于提高CO转化率.O2/CO增加也可提高CO转化率,但O2/CO的增加并不能提高CO氧化的选择性.为了同时得到CO高转化率和CO氧化高选择性,O2/CO(V∶V)为1.0～1.8.用BET、XRD和CO-TPD等表征方法说明了K2O的助催效应.     

甲烷部分氧化制合成气反应机理的原位时间分辨IR光谱和Raman光谱表征

采用原位时间分辨红外光谱、原位显微Raman光谱、脉冲反应－质谱、TPR和以CO为探针分子的IR光谱等技术对SiO2、γ-Al2O3负载的Rh、Ru催化剂上甲烷部分氧化（POM）制合成气反应机理进行了研究。实验结果表明，在H2还原的Rh/SiO2上，CO是VCH4／VO2／VAr(2/1/45)混合气反应的初级产物，由CH4直接氧化生成CO和H2是该催化剂上POM反应的主要途径。CO2是Ru/SiO2和Ru/γ-Al2O3上POM反应的初级产物，因而燃烧－重整机理是相应催化剂上CO和H2生成的主要途径。反应条件下催化剂表面氧（O^2-)物各浓度的差异很可能是导致上述催化剂体系上POM反应机理不同的主要原因，其本质可能源于Rh和Ru对氧的亲合力的不同。Rh/γ-Al2O3上POM反应的机理与催化剂的焙烧温度有关，当焙烧温度低于600℃时，催化剂的POM行为与Rh/SiO2类似，CO为反应的初级产物，当焙烧温度为900℃时，CO2为POM反应的初级产物。不同焙烧温度的Rh/γ－Al2O3上POM反应机理不同的主要原因之一也取决于反应条件下催化剂表面氧物种浓度差异，其本质可能源于高温（900℃）焙烧的催化剂中Al2O3与Rh物种间存在着较强的相互作用，从而降低了Rh物种的可还原性。     

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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