硫脲型整合树脂在分析上的应用 Ⅰ.岩样中微量银的中子活化分析

前言银和其他贵金属元素一样,在地壳中比较稀少,按其自然丰度为第67号元素,平均含量仅0.07 ppm。由于地质样品成分非常复杂,为测定其微量银,必须进行严格的化学分离。但是迄今文献中报道的许多分离分法,步骤都相当冗长,一般采用氯化银反     

EMD与KOH溶液的相互影响

利用滴定分析、热失重分析以及XRD方法研究了EMD和KOH溶液混合后的变化。结果表明:碱与MnO2可以相互作用并导致体系温度的升高,碱浓度的下降,EMD中形成Mn3O4以及MnO2中结合水的损失。相互作用的结果与所加KOH溶液的浓度、EMD中的水含量、二者用量的比例关系以及体系的温度有关。     

Development of nano indium tin oxide (ITO) grains by alkaline hydrolysis of In(III) and Sn(IV) salts

Indium tin oxide (ITO) nano powders of different compositions (In: Sn = 90: 10, 70: 30 and 50: 50) were prepared by heat treatment (300-450°C) of mixed hydroxides of In(III) and Sn(IV). The hydroxides were obtained by the reaction of aq. NH₃ with mixed aq. solutions of In(NO₃)₃ and SnCl₄. FTIR and TG/DTA studies revealed that powders existed as In(OH)₃H₂O—SnO₃H₂H₂O in the solid state and then they transformed to In₂O₃—SnO₂ via some metastable intermediates after 300°C. Cubic phase of In₂O₃ was identified by XRD for the oxides up to 30% of Sn. Particle size measurements of the solid dispersed in acetone and SEM study for microstructure showed that the oxides were in the nano range (55-75 nm) whereas the size range determined from Debye-Scherrer equation were 11–24 nm.     

苯基荧光酮分光光度法测定聚烯烃树脂中的钛

应用苯基荧光酮 -聚乙烯醇 -Tween -80显色体系测定了聚烯烃树脂中的钛 ,建立了测定聚烯烃树脂中钛离子的灵敏、快速的分析方法。考察了测定条件 ,在测定过程中 ,以抗坏血酸还原作用消除了Fe3+ 、V5+ 等干扰。配合物最大吸收波长为 5 3 5nm ,其表观摩尔吸光系数ε =1 0× 10 5L/ (mol·cm) ,线性范围为 0～ 0 12 μg/ml。合成试样回收率为 97 3 %～ 10 1% ,相对标准偏差不大于 1 63 % ;加标回收率为 99 95 %～ 10 1 3 % ,该方法选择性高 ,准确性好 ,简便易行     

Electroplating of nickel-cadmium alloys from alkaline solutions

The electroplating of Ni-Cd alloy coatings was carried out from alkaline baths (pH 10). For comparison, electroplating of the parent metals, Ni and Cd, was performed individually under the same conditions. The cathodic current efficiency for codeposition was high and decreased with increasing current density. The codeposition process is an anomalous type of plating with Cd being the preferentially deposited metal. The Ni content in the deposits increased with increasing current density. This increase in Ni content improves the corrosion resistance and microhardness of the deposits. X-ray diffraction analysis showed that the deposits consist of a mixture of Ni, β, γ, γ¹ phases.     

一步法合成松香改性酚醛树脂

探讨了一步法合成松香改性酚醛树脂的反应机理，确定了最佳原料组成及合成工艺，由此制备出高溶解粘度和矿油容纳度的松香改性酚醛树脂，是一种性能优异的高级胶印油墨连接料     

Synthetic resins: XV. Chelation ion exchange properties of 2,4- dinitrophenylhydrazone of resacetophenone-formaldehyde resin

A number of copolymers were synthesised by condensing the 2,4-dinitrophenylhydrazone of resacetophenone with substituted benzoic acids/ phenols and formaldehyde in the presence of sodium hydroxide or hydrochloric acid. The decomposition temperature, solubility and viscosity of the polymers have been determined. The ion-exchange properties have been studied by using a batch equilibrium method. The distribution of a number of metal ions between an aqueous solution and the resin have been measured. A wide range of pH and variable ionic strengths have been investigated.     

稀土树脂相分光光度法研究

在HCl—KCl(pH0.5)介质中,稀土—三溴偶氮胂二元络合物能较好地被阴离子交换树脂吸附。RE_2O_8在0～8μg/25ml范围内符合比尔定律,以双波长等吸收点法(测量波长λ_1=650nm,参比波长λ_2=740nm)扣除树脂背景影响,应用于稀土矿中稀土总量测定,结果令人满意。     

Microstructure-related fracture toughness and fatigue crack growth behaviour in toughened, anhydride-cured epoxy resins

Fracture toughness and fatigue crack propagation (FCP) of plain and modified anhydride-cured epoxy resin (EP) were studied at ambient temperature. Liquid carboxyl-terminated acrylonitrile-butadiene (CTBN) and silicon (SI) rubber dispersions were used as tougheners for the EP. The morphology of the modified EP was characterized by dynamic mechanical analysis (DMA) and by scanning electron microscopy (SEM). The fracture toughness, K_c, of the compositions decreased with increasing deformation rate. K_c of the EP was slightly improved by CTBN addition and practically unaffected by incorporation of the SI dispersion when tests were performed at low cross-head speed, v. Both modifiers improved K_c at high v, and also the resistance to FCP, by shifting the curves to higher stress intensity factor ranges, ΔK, by comparison with the plain EP. It was established that both fracture and fatigue performance rely on the compliance, J_R, at the rubbery plateau, and thus on the apparent molecular mass between crosslinks, M_c. The failure mechanisms were less dependent upon the loading mode (fracture, fatigue), but differed basically for the various modifiers. Rubber-induced cavitation and shear yielding of the EP were dominant for CTBN, whereas crack bifurcation and branching controlled the cracking in SI-modified EP. The simultaneous use of both modifiers resulted in a synergistic effect for both the fracture toughness at high deformation rate and the FCP behavior.