稀土在低硫铌钛钢中的作用

在实验条件下采用50kg真空感应炉炼和两段控制轧制工艺，并采用WE－60型万能拉伸试验机，JB－30B型冲击试验机，MM6型及OLYMPUS－PME3型光学金相显微镜，IBAS－2000图相分析等手段研究了稀土对低硫铌钛钢性能，组织及夹杂物的影响。在低硫铌钛钢中的试验结果表明，稀土元素的加入使力学性能变化各异，它使钢的横向屈服点和抗拉强度先下降而后上升；延伸率则无下降而后上升；稀土对钢的横向冲击功则表现为先上升而后下降，并且在－20℃以上，适量的稀土加入可以明显改善其冲击功的各向异性；稀土的加入并不能改变钢的显微组织类型，钢的组织为铁素体＋珠光体，但稀土会使钢中珠光体数量增加，铁素体数量减少，在钢中夹杂物方面，稀土加入则表现为它一方面 化钢液，使钢中夹杂物数量减少，另一方面是使钢中夹杂物的颗粒球化，细化和弥散化，从而改善夹杂物的分布。     

高镍钢中镍的测定

以王水溶解试样，用氨水作沉淀剂，并加入适量三乙醇胺及柠檬酸进行掩蔽，以消除铁及铬等元素的干扰，在pH=3-6的酸性介质中，加入过量的EDTA标准溶液，使镍与EDA形成稳定的络合物，以PAN为指示剂，用硫酸铜标准溶液滴定过量的EDTA标准溶液，从而求得镍的含量。     

溶胶-凝胶法制备高取向Bi4Ti3O12/SrTiO3(100)薄膜

Bi4Ti3O12具有良好的铁电、电光等性能山、特别是Bi4Ti3O12薄膜很适合作永久性存储材料，也可用于电光器件问．在微电子学、光电子学、集成光学、集成铁电学等领域均有广泛开发和应用前景，国外已用溅射法、激光沉积法制备出c轴取向Bi。Ti3Ol。薄膜【’，＼山东大学用MOCVD法制     

Determination of boron in boron-alloyed steels by inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) procedure has been developed and examined for the determination of boron content (0.01 up to about 2% B) in boron-alloyed steels such as POLDI ATA BOR (65% Fe, 19%Cr, 12% Ni, 1.5% Mn, 1% B), POLDI ATA BOR EXTRA (62% Fe, 18% Cr, 13% Ni, 2.5% Mo, 1.5% Mn, 1% B) and POLDI ATA BOR-R (75% Fe, 18% Cr, 3.5% Ti, 1.8% B). The steel sample is dissolved with a mixture of hydrochloric, nitric, sulfuric and phosphoric acids in a quartz vessel. Borides of alloyed metals, especially of iron and chromium, are quantitatively decomposed. The presence of phosphoric acid in a sample solution reduces the volatility of boric acid with water vapour.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Aminolysis ofO-alkylO-4-nitropyenyl chloromethylphosphonates in reverse micellar solutions of the nonionic surfactant

The reaction ofn-hexylamine withO-alkylO-4-nitrophenyl chloromethylphosphonates in toluene solutions of poly(ethylene glycol)-600 monolaurate (PM) has been studied by spectrophotometry. The reverse micelles of the nonionic surfactant increase more than tenfold the observed rate constant of aminolysis. The catalytic activity of the surfactant is practically independent of the alkyl radical length of phosphonate. An increase in the concentration of amine results in a decrease in the catalytic efficiency. The character of the dependence of the rate constant on the concentration of PM is affected by the alkyl chain length of the substrate. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1735–1738, September, 1998.     

Ascorbate oxidase

Ascorbate oxidase fromCucurbita sp. was isolated by ammonium sulfate precipitation and DEAE-dextran-silochrome column chromatography. The thermal and pH stabilities of the purified enzyme were investigated. TheK _M forl-ascorbic acid (1.5 mM) and chlorohydroquinone (0.37 mM) was determined. Substrate specificity of ascorbate oxidase was investigated and compared with those of laccases fromCoriolus hirsutus andCerrena maxima. Ascorbate oxidase was covalently bound to a polymeric membrane and used in an enzyme electrode for ascorbic acid.     

稀土变质热锻模具铸钢高温磨损性能的研究

研究了稀土（RE）变质热锻模具铸钢的高温磨损性能，并与热锻模具钢H13钢和3Cr2W8V钢进行对比，探讨了稀土元素的作用和热锻模具铸钢的高温磨损机理。结果表明：随着RE加入量的增加，热锻模具铸钢的磨损率先减后增，RE加入量在质量分数为0．05％时热锻模具铸钢具有最佳的高温磨损性能。RE变质热锻模其铸钢的高温耐磨性明最高于H13钢和3Cr2W8V钢。高温磨损机理为氧化磨损和氧化物的疲劳剥落，磨屑为块状的Fe2O3和Fe3O4。     

Extraction-spectrophotometric study on the vanadium(V)-2,3-dihydroxynaphthalene — iodonitrotetrazolium chloride — water — chloroform system and its analytical application

The formation of a new ternary ion-associate complex of vanadium(V) with 2,3-dihydroxynaphthalene and iodonitrotetrazolium chloride with a composition ratio of 1:2:1 is reported. The complex is quantitatively extracted from water into chloroform. The molar absorptivity (ɛ) of the extract at λ _max=340 nm is 2.5 × 10⁴ dm³/mol cm, and Beer’s law is obeyed for concentrations ranging from 0.1 to 0.9 μg/cm³ V(V). The following constants are determined: the extraction constant, the association constant, the distribution constant, and the recovery factor. The effects of foreign ions and reagents are studied. A selective and sensitive method is developed for determination of vanadium in steels.     

Synthesis of an enzyme-like imprinted polymer with the substrate as the template, and its catalytic properties under aqueous conditions

Transition state analogues (TSAs) have long been regarded as ideal templates for the preparation of catalytically active synthetic imprinted polymers. In the current work, however, a new type of molecularly imprinted polymer (MIP) was synthesized with the substrate (homovanillic acid, HVA) as the template and hemin introduced as the catalytic center, with the use of plural functional monomers to prepare the active sites. The MIP successfully mimicked natural peroxidase, suggesting that it may not be imperative to employ a TSA as the template when preparing enzyme-like imprinted polymers and that the imprinted polymer matrix provided an advantageous microenvironment around the catalytic center (hemin), essentially similar to that supplied by apo-proteins in natural enzymes. Significantly, by taking advantage of the special structure of hemin and multiple-site interactions provided by several functional monomers, the intrinsic difficulties for MIPs in recognizing template molecules in polar solutions were overcome. The newly developed polymer showed considerable recognizing ability toward HVA, catalytic activity, substrate specificity and also stability, which are the merits lacked by the natural peroxidase. Meanwhile, the ease of recovery and reuse the MIP implies the potential for industrial application.     

Study on the anodic reaction of Ni in an alkaline solution by transient pH detection based on scanning electrochemical microscopy (SECM)

The anodic reaction of Ni in an alkaline solution was studied by the tip–substrate voltammetry mode of scanning electrochemical microscopy (SECM) and cyclic voltammetry (CV). A platinum microdisc electrode was selected as the tip electrode, which functioned as a pH sensor with transient response capability. The pH value of the solution near the Ni electrode surface varied while the Ni substrate oxidation reaction occurred, and the pH variation could be detected by the tip faradic current. The cyclic voltammogram results showed that two types of hydroxides: i.e. α‐Ni(OH)₂ and β‐Ni(OH)₂ were formed during Ni oxidation in the lower potential region. In the proceedings of α‐Ni(OH)₂ → γ‐NiOOH and β‐Ni(OH)₂ → β‐NiOOH, the process of OH^? concentration decrease in the solution was ahead and behind of electron transfer in the solid phase, respectively. These results indicate that the OH^? adsorption process occurs as an elementary step in the former reaction and the H⁺ diffusion process from the inner to the outer layer of the solid phase occurs as a subsequent step in the latter reaction. The results also revealed that the oxide film on the Ni surface has a two‐layer structure. The real potential of the oxygen evolution reaction (OER) on the Ni surface with different cycles is also analyzed in the paper. Copyright © 2007 John Wiley & Sons, Ltd.