高温超导体制备条件的人工神经网络识别

高温超导体的制备条件要求严格,其掺杂量大小、烧结温度控制等都直接影响实验样本的超导性质。近几年高温超导研究已积累大量实验数据,如何应用人工智能方法处理这些数据寻找更好的合成条件颇有意义。人工神经网络方法在许多领域己显示其处理复杂数据和模式识别的优越性,但尚未应用到化合物制备研究方面。本文对此作了初步尝试。     

硅钼杂多阴离子薄膜修饰电极的研究和应用——线性扫描伏安法测定水中可溶性硅酸盐

本文研究了以玻碳电极为基体的1:12硅钼杂多酸根(SiMo_(12)O_(40)~(4-)简称12-MSA)修饰电极的制备及其电化学行为,将12-MSA电极应用于线性扫描伏安法测定天然水中可溶性硅酸盐,结果满意.硅浓度在8.0×10~(-7)～1.7×10~(-3)mol/L,相对标准偏差(n=7)为1.85％,加标回收率为98.2％～103.6％,SiMo_(12)电极具有优良的选择性和稳定性。     

SAPO－5，－11和－34分子筛模板剂的脱除及其结构的热致变化

用水热法合成了ＳＡＰＯ－５，－１１和－３４硅磷酸铝类分子筛。并对经不同温度焙烧处理的样品进行表征，结果表明：分子筛中模块剂的热分解过程与其结构和孔大小有较大的关系。在ＳＡＰＯ－５和ＳＡＰＯ－３４分子筛中，外部联接的Ｔ－Ｏ－Ｔ键的反对称伸缩振动峰（１２４０ｃｍ~（－１）－１０３８ｃｍ~（－１））和其对称伸缩振动（７３４ｃｍ~（－１）－６００ｃｍ~（－１））及双环的变形振动（６００－５００ｃｍ~（－１））的吸收峰对样品的结晶度比较敏感。但在ＳＡＰＯ－１１中，分子筛骨架中Ｔ－Ｏ－Ｔ反对称伸缩振动（１２２５ｃｍ~（－１）和１０３８ｃｍ~（－１））随结晶度的下降而基本保持不变，但内四面体（ＴＯ_４）的对称伸缩振动，反对称伸缩振动峰及Ｔ－Ｏ弯曲振动峰随样品焙烧温度的升高而减弱并分裂。红外吸收带向低频方向移动。ＳＥＭ－ＥＤＡＸ结果表明：随样品焙烧温度的升高，结晶度下降，分子筛晶形变得不规则，晶面越来越粗糙，但结晶度的下降并非由于其中ＰＯ_４四面体的热分解所引起，而是由外部联结的Ｔ－Ｏ－Ｔ键的断裂，双环被破坏及骨架元素间的重排所引起。     

Single-Molecule single crystals of isotactic polystyrene

Single-molecule single crystals were grown from amorphous droplets of fractionated isotactic polystyrene. The crystals were analyzed by electron microscopy and electron diffraction. The molecular mass distribution could be matched with a statistical analysis of single-molecule particles (amorphous and crystals). Proof was brought that single molecules of isotactic polystyrene do not reach equilibrium dimensions on crystallization, rather assume the lamellar morphology with chain-folded macroconformation, also known from crystallization of polymolecular crystals. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America. US Government contract No. DE-AC05-840R-21400.

     

用DSC研究纯三水铝石溶出动力学

在DSC上研究了NaOH溶液中合成三水铝石的溶出过程动力学。应用非等温反应动力学模型计算了动力学参数,分析和确定了反应机理。模型计算结果与用DSC测得的结果吻合。     

Synthesis, Crystal Structure and NLO Properties of a Novel Ruthenium(II) Complex with Unusual Coordination Mode

A new Schiff base 4-[N-hydroxyethyl-N-(methyl)amino]benzaldehyde S-methyl dithiocarbazate (HL, where H is a dissociable proton) and the ruthenium complex [Ru(bpy)₂L]PF₆ (bpy = 2,2′-bipyridine) have been synthesized. The structural determinations of the ligand and its ruthenium complex, by X-ray crystallography, show that the ligand is coordinated as a monoanionic bidentate N, S-donor, forming a four-member chelate ring with a bite angle of 65.91°. The complex shows intense MLCT transitions in the visible region. Fluorescent and electrochemical properties have been also studied. The complex in DMF solution exhibited a strong two-photon absorption (t.p.a.) at 532 nm nanosecond laser pulses. The t.p.a. coefficient β, t.p.a. cross-section σ and the third-order optical nonlinearity χ⁽³⁾ of the complex and the ligand have been determined by the Z-scan technique.     

Effects of Calcination on the Physical and Photocatalytic Properties of TiO<Subscript>2</Subscript> Powders Prepared by Sol–Gel Template Method

TiO₂ powders were prepared by sol–gel template method and calcined under different conditions. XRD, BET and TEM were used to characterize the TiO₂ powders obtained. The photocatalytic activity of TiO₂ was investigated by the degradation of methyl orange. It was found that TiO₂ powder has the highest photocatalytic activity at a calcination temperature of 673 K. The effects of physical properties such as surface area, crystallinity and crystal phase on the photocatalytic activity of TiO₂ were discussed.     

乙二胺铜－铁氰复合修饰电极薄膜的电沉积和结构表征及电化学性质

乙二胺铜－铁氰复合修饰电极薄膜的电沉积和结构表征及电化学性质陈昌国，李海梅，黄宗卿（重庆大学化工学院重庆６３００４４）关键词：铜、乙二胺，铁氰，修饰电极，光谱普鲁士兰（ＰＢ）修饰电极因其独特的电致变色现象而倍受关注。在１９７８年以来的十余年间里已相继...     

ANN原子参数法预报合金相晶型及晶格常数

运用人工神经网络方法，以二元合金组成元素的电子结构为基本特征，对二元合金相晶型作了区分，进一步对其晶格常数作了预报，结果令人满意。     

用共振电离飞行时间质谱仪分析土壤中超痕量气态金

采用激光共振电离飞行时间质谱技术（简称ＲＩＳ－ＴＯＦ技术）对土壤中超痕量气态金的含量进行了分析研究。ＲＩＳ－ＴＯＦ谱仪具有极高的灵敏度和很强的选择性，避免了对样品的预富集过程。本文给出了该谱仪对金元素的检测限和６５个土壤中气态金样品的分析结果，以及用中子活化法随机抽样检查的结果。