掺杂La_2O_3的CuW电触头的组织及电性能

采用液-固掺杂工艺将La(NO3)3与WO3混合,经干燥、La(NO3)3裂解和WO3还原等工艺制备含有La2O3的稀土W粉,采用粉末冶金-熔渗法制备含有La2O3的CuW电触头;研究了保温时间对La(NO3)3裂解的影响以及La2O3对CuW电触头性能的影响. 结果表明:用液-固混料法制备的稀土W粉,La2O3分布均匀,粉末粒度较细;La(NO3)3裂解粉末的颗粒随着保温时间的延长而长大;掺杂La2O3的CuW触头耐电弧烧蚀性能有显著的提高.     

Mn2O3/HY催化聚丙烯的临氧裂解反应动力学

采用热重分析仪,在常压O2气氛(流量为50 mL/min)中,以不同的速率(10、20和30℃/min)升温,研究Mn2 O3/HY催化聚丙烯的临氧裂解反应,采用高斯拟合峰模型对反应进行分析,并使用分布活化能模型(DAEM)得到动力学预测曲线.结果表明:高斯拟合峰模型可以对聚丙烯临氧裂解各反应阶段进行较好的拟合,聚丙烯...     

钒掺杂改性层状钙钛矿K2La2Ti3O10的光催化性能

通过高温固相法,制备出V5 掺杂的K2-xLa2Ti3-xVxO10 (x=0～1.0) 系列层状钙钛矿.采用X 射线衍射、紫外可见漫反射光谱和比表面积对样品进行表征.研究K2-xLa2Ti3-xVxO10 作为光催化剂在波长大于290 nm 光辐射下,裂解水产生氢气的光催化活性,并讨论V5 掺杂对层状钙钛矿K2La2Ti3O10 光催化活性的影响.实验结果表明,适量掺杂的V5 可有效地提高K2La2Ti3O10 裂解水的光催化活性,450 W 汞灯照射5 h 后,1 g的K2-xLa2Ti3-xVxO10(x=0.1) 光催化剂可催化分解甲醇溶液(体积分数为10%)产生氢气约16 μmol.     

镍基催化剂上焦油组分裂解反应研究

以甲苯为煤焦油模型化合物,研究了镍基催化剂对焦油组分催化裂解反应特性的影响.采用浸渍和分步浸渍的方法制备了Ni/Al2O3和Ni/MgO-Al2O3两个系列镍基催化剂,考察了催化剂组成(Ni含量、MgO含量)、反应条件(温度、空速、水蒸气含量)对焦油组分催化转化的影响.结果表明:Ni含量在0.2％左右时,Ni/Al2O3具有较高的催化活性,催化剂的活性随着Ni含量的继续增加而下降,作为助催化剂的MgO可以减少催化剂表面积炭.高温有利于H2和CO的生成,但不利于CH4的生成.水/甲苯比是影响焦油催化裂解的重要因素,较高水/甲苯比有利于H2的产生,而不利于CO和CH4的生成.     

臭氧与丙烯酸丁酯反应机理的理论研究

在B3LYP/6-31+G(d,p)水平上优化了臭氧与丙烯酸丁酯反应体系各驻点物种的几何构型,并在相同水平上通过频率计算和内禀反应坐标(IRC)分析对过渡态结构及连接性进行了验证.采用G3//B3LYP方法对所有驻点进行单点能计算,构建了O3+CH3CH2CH2CH2OC(O)CHCH2反应体系的势能剖面,对Criegee自由基的单分子异构化反应进行了分析.研究结果表明,丙烯酸丁酯的臭氧化反应符合Criegee机理,存在两种反应路径,根据势能面分析,生成产物CH2OO和CH3CH2CH2CH2OC(O)CHO的反应是臭氧化物中间体(IM)裂解的优势路径.其Criegee自由基CH2OO和CH3CH2CH2CH2OC(O)CHOO因不具有α-CHn基团(n=1,2,3)而不可能发生单分子氢迁移异构化反应,只可通过环化异构化反应通道形成具有双氧环状结构的最终产物CH2O2和CH3CH2CH2CH2OC(O)CHO2.     

CH_2=C(CH_3)COOCH_3+O_3反应机理及主通道速率常数的理论研究

采用CBS-QB3方法构建了CH_2=C(CH_3)COOCH_3+O_3反应体系的势能剖面,并对其反应机理及速率常数进行了研究.计算表明,标题反应首先经过渡态TSa生成一个稳定的五元环臭氧化物中间体IMa,然后中间体IMa按不同O-O键的断裂方式发生五元环裂解反应,分别生成产物P1(CH_2OO+CH_3OC(O)C(CH_3)O)和P2(CH_2O+CH_3OC(O)C(CH_3)OO).利用经典过渡态理论(TST)并结合Wigner矫正模型计算了200~1200 K范围内标题反应的速率常数K~(TST/W).结果表明,294 K时,CH_2=C(CH_3)COOCH_3+O_3反应速率常数为4.76×10~(-18)cm~3·molecule~(-1)·s~(-1),与Bernard等对类似反应所测的实验值十分吻合.     

助燃催化剂对煤粉在高炉喷吹快速热解中的影响

选取KMnO4、Fe2O3、MnO2和CaO作为助燃催化剂,采用H2/Ar等离子体热解试验装置和快速升温热解红外连用试验装置来模拟煤粉在高炉喷吹条件下的快速热解过程,对混合煤粉的快速热解过程进行了研究,得到了助燃催化剂与煤的裂解程度(裂解气体收率)、裂解气体成分的关系,对助燃催化剂的催化裂解机理进行了讨论。     

助燃催化剂对煤粉在高炉喷吹快速热解中的影响

选取KMnO4、Fe2O3、MnO2和CaO作为助燃催化剂,采用H2/Ar等离子体热解试验装置和快速升温热解红外连用试验装置来模拟煤粉在高炉喷吹条件下的快速热解过程,对混合煤粉的快速热解过程进行了研究,得到了助燃催化剂与煤的裂解程度(裂解气体收率)、裂解气体成分的关系,对助燃催化剂的催化裂解机理进行了讨论。     

聚酰亚胺高温热解反应的分子动力学模拟

使用ReaxFF分子动力学(ReaxFF-MD)模拟方法研究聚酰亚胺固化物在3 000、3 500和4 000 K温度下的热裂解特性.结果表明,热解的引发反应主要是酰胺键的断裂,热解的主要产物是H_2O、H_2和大分子碳团簇,同时观察到少量CO、HCN和N_2等小分子.当反应温度升高,裂解速度加快,其中H_2生成速率明显加快.分别观察到H_2O和H_2的2种主要生成途径.反应过程中可以观察到类似石墨烯结构的碳团簇的形成.使用ReaxFF方法模拟聚酰亚胺高温热解可以得到与实际实验相一致的结果并能跟踪反应过程.     

蒜头果油臭氧化物的裂解方法研究

开展了蒜头果油臭氧化物的安全裂解方法的研究,考察了用O2和H2O2两种氧化剂裂解臭氧化物生成ω-羧基长链脂肪酸三甘油酯的反应条件.实验结果表明:蒜头果油臭氧化物用H202进行裂解比用Q反应条件温和,1,15.十五二酸二甲酯的得率更高.在55℃下用H2O2作为氧化剂,裂解反应2 h,1,15-十五二酸二甲酯的得率达到80.51%.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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