自蔓延冶金法制备硼粉的基础研究

提出采用自蔓延冶金法制备硼粉的新工艺·计算知B2O3 Mg反应体系的绝热温度(Tad)为2604K,对B2O3 Mg反应体系的相关反应进行了热力学分析,确定了采用自蔓延模式的可行性·差热分析(DTA)表明反应体系850～930℃放热峰的表观活化能为903 75kJ·mol-1,反应级数为n=1·X射线衍射分析表明燃烧产物主要由MgO,Mg3B2O6和B2O3等相组成,确定了燃烧产物的浸出条件以及三步浸出方案·光谱分析及化学分析表明硼粉纯度可达92 43%,平均粒度为0 5～0 8μm·     

激光气相法制备超细硼粉工艺参量监测

用３００Ｗ ＣＷ－ＣＯ２激光引发化学气相反应，以ＢＣｌ３和Ｈ２为原料制备超细硼粉，非接触式测温方法监测反应焰温度、反应焰模式以及反应参量对反应焰温度的影响规律。Ｈｅ－Ｎｅ激光粉体密度测定法监测粉体制备的动态过程，给出有关计算方法，并测定了粉体在反应焰中的分布状态。     

无定形硼粉的HTPB团聚新方法改进

以端羟基聚丁二烯（HTPB）为主要原料,乙醇、乙酸乙酯为溶剂,对无定形硼粉进行了团聚改性处理,研究了团聚改性后硼粉对密度的影响,采用XPS光电子能谱,透射电镜、红外光谱等手段分析了硼粉改性效果,总结了其相关性能的表征结果,并对无定形硼粉改性前后与HTPB混合物黏度进行了测试分析。结果表明,无定形硼粉团聚改性后,硼粒子的球性度提高,松装密度大大增加,其表面明显有一层包覆层,而且与HTPB混合物的黏度较无定形硼粉的大大降低,这对制备推进剂药浆工艺性能有利。     

机械磨细对新疆和田地区火山岩粉活性影响试验

为了提高新疆和田地区火山岩粉的活性,拓宽其在混凝土工程中的应用,借鉴目前常用的机械磨细的球磨方法,使粉体材料更加细化,并改善其颗粒分布。对4种细度的火山岩粉,采用勃氏法测试其比表面积,激光粒度法分析其颗粒级配及分布,多龄期胶砂强度指数法去验证掺加该火山岩粉后的胶凝体系宏观力学性能变化,最后用SEM及EDS观察分析微观形貌及产物,揭示微观变化与宏观强度,即火山灰活性提升的关系。试验结果表明:机械磨细的方法可以有效地改善火山岩粉的颗粒分布,比表面积每增加80 m²/kg左右则小于50%通过率颗粒粒径减小0.6~0.8 μm;掺火山岩粉胶凝体系随龄期的延长,宏观上其抗折强度和抗压强度均有持续的提高,而且抗折强度增加速率更快,但强度增加随火山岩粉变细而增长的幅度放缓。根据宏观力学性能的变化及SEM及EDS的微观观察分析,得出结论:机械磨细可提高火山岩粉活性的主要原因为颗粒变细的“微集料”填充作用,以及其参与水泥基体系水化反应能力的提升。     

不同粉磨工艺水泥的颗粒、矿物组成分布及性能

研究了采用不同粉磨工艺制备的水泥的颗粒分布及矿物组成分布对水泥与混凝土物理性能的影响．研究结果表明：水泥颗粒分布与粉磨设备条件及工艺参数密切相关,选用高效选粉机,增大循环负荷及控制适当的比表面积,可获得较窄的颗粒分布;由于C3S易磨性较好,易富集于水泥细颗粒中,通过提高水泥颗粒的集中程度及适当增大比表面积,可有效地把熟料中的C3S富集于30μm以下的水泥颗粒中;当水泥熟料质量、混合材质量、水泥比表面积控制水平较接近,水泥颗粒分布集中(主要集中在5～30μm范围)时,水泥的标准稠度需水量较大,凝结时间较长,1d强度较低,但3d,28d抗压强度较高,在混凝土中则表现为新拌混凝土泌水较严重,1d抗压强度偏低,3d．28d抗压强度增幅较大．     

激光热解制备超细硅粉

通过激光引发化学气相热解反应，在连续流动体系中，由原料硅烷（ＳｉＨ４）制备了超细硅粉．不同焰温制备出的粉体可以由非晶态到晶态变化．采用非接触测温技术，研究了反应参数的变化对反应焰温的影响．粉体ＴＥＭ测定结果表明为单分散球形颗粒．     

纳米Ni粉对肉桂醛选择性加氢反应性能研究

文章采用固相法合成纳米Ni粉,通过XRD、XPS、TEM、SEM和IR等测试手段对其结构进行了表征,并对纳米Ni粉进行掺杂贵金属Pt、Pd改性,以肉桂醛选择加氢反应为探针反应,考察催化剂的催化加氢性能。研究结果表明,固相法合成的纳米Ni粉为高纯度、粒径分布均匀的纳米颗粒,平均粒径为24 nm。对纳米Ni粉和改性的纳米Ni粉的催化加氢性能的考察结果显示,上述催化剂催化肉桂醛加氢反应的催化能力表现为:Pd掺杂的纳米Ni粉纳米Ni粉Pt掺杂的纳米Ni粉。     

碳化铬/铁基自熔合金复合涂层真空反应钎涂

以纯铁粉、硅粉、硼铁粉、铬铁粉、胶体石墨及镍粉为原料,通过真空反应钎涂在低碳钢基体上制备了碳化铬/铁基自熔合金复合涂层,涂层表面光滑、平整且与基体为冶金结合.应用扫描电子显微镜、能谱仪、X射线衍射仪及显微硬度计,研究了涂层的组织结构、成分分布和硬度分布.结果表明:涂层为复合结构,其组织由Fe-Ni固溶体基底和原位合成的六棱柱Cr3C2相组成.涂层与基体间存在过渡区,过渡区内元素和硬度呈梯度分布;涂层表面硬度可达85HR15N以上.     

木薯淀粉接枝丙烯酸的研究

研究了木薯淀粉与丙烯酸的接枝共聚合反应.选用(NH_4)_2S_2O_8、FeCl_3、H_2O_2—FeSO_4、KMnO_4等不同引发剂作比较,结果表明过硫酸铵是一种很有开发前景的引发剂,其最佳反应条件是丙烯酸浓度为1M,反应温度为50℃,反应时间为2h.对所得共聚物的吸水量及保水率进行了测试.     

轻烧粉-氢氧化钠法制备氢氧化镁的研究

以轻烧粉经酸化、氧化除铁等精制过程得到的氯化镁溶液为原料,以氢氧化钠为沉淀剂制备氢氧化镁。研究了pH值对轻烧粉酸化除铁的影响,考察了原料的物质的量比、反应温度、加料时间、陈化时间等因素对产品质量的影响,得到了轻烧粉精制和反应制备氢氧化镁的最佳工艺条件。采用扫描电子显微镜（SEM）、X射线粉末衍射仪（XRD）和激光粒度分布测试仪等对实验产品进行表征。结果表明,该工艺制备的氢氧化镁纯度达到98%以上,CaO质量分数低于0.1%,颗粒呈片状结构,粒度分布均匀,形貌规则。     

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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