Transmission Electron Microscopic Observation of the Martensitic Phase Transformation in Tetragonal ZrO2

The present work involves the observation of phase transformation in Y₂O₃-containing tetragonal ZrO₂ polycrystals (Y-TZP) using electron microscopy. The observations indicate that the martensitic phase transformation ususally starts from grain boundaries. Transformation was also observed at the tip of a microcrack and its adjacent region. Our observations also indicate that the tetragonal ZrO₂ grains do not all transform at the same time at the fracture surfaces.     

Influence of Antioxidants on Maillard Browning Reaction in a Casein-Glucose Model System

Mixtures of casein and glucose with and without antioxidants were prepared to give a moisture content of 11%, and stored at 37°C. under 60% relative humidity for O-60 days. The effects of antioxidants on the Maillard reaction were monitored by browning, available lysine and furosine level. Browning decreased with the addition of α-tocopherol, BHT, BHA or propyl gallate but not ascorbic acid in mixtures stored 60 days. All antioxidants improved the retention of available lysine and lowered the concentration of furosine compared to the control.     

~(99)Mo-~(99m)Tc同位素辐照靶件研制

本文叙述了用含10%~(235)U燃料棒芯体,研制~(99)Mo-~(99m)Tc同位素辐照靶件的制备工艺。研制工艺分为:将燃料芯体铝包壳用碱溶法减壁厚,芯体切割,压密合,旋压端塞,焊封以及质量检验等工艺。研制出的靶件经入堆考验和同位素分离等实验,证明性能良好,结构合理。为钼-鍀同位素实验研究和生产创造了有利条件。     

GK1F型机车油水分离器冻结的原因及改进措施

1前言莱钢集团运输部现有GK1F型机车9台,由于生产节奏不断加快,机车运用率高达90%以上,致使机车故障增加。而冬季机车油水分离器空气管路被冻结的故障更为严重,管路积水排不出,严重影响机车制动效果,危及机车的安全运行。2原因分析经分析发现,问题根源为油水分离器的排污阀,GK1     

氚在305铝合金及其预生膜中渗透率的研究

文章叙述了氚在305铝合金及其预生膜中渗透率的测量方法,推导出计算氚在305铝合金及其预生膜中的渗透率的经验公式。实验结果表明氚在镀预生膜的铝中的渗透率低,在100-250℃铝表面镀层阻挡氚渗透效果极为明显,而且温度越高效果越显著。     

一种保鲜膜重卷机的优化方案及其实现

介绍了对保鲜膜重卷机进行优化的一种有效方案。对保鲜膜卷绕长度的计量进行细分,并用电感式接近开关替代传统的机械式行程开关,从而实现了对保鲜膜长度的精确控制。     

Defect Centers in Gamma-Irradiated Single-Crystal Al2O3

The γ-irradiation-induced optical absorption spectra of annealed Al₂O₃ single crystals were analyzed. The samples were beat-treated in O₂ or vacuum from 1600° to 1800°C. Four absorption bands are reported with average peak positions at 3.4,4.8,5.5, and 6.6 eV for samples annealed in O₂ at ≥ 1750°C. Vacuum anneals up to 1800°C and O₂ anneals at < 1700°C failed to generate observable bands in the energy range studied. There is also evidence that one or more bands exist at >6.6 eV. The radiation-induced change in the absorption spectra is reported and the defect centers responsible for the measured optical absorption bands are discussed with respect to the aliovalent impurities in the host lattice. Special attention is given to the role of the Fe³⁺ impurity ion.     

硅肥中有效硅含量的测定方法研究

采用氟硅酸钾容量法对硅肥中测定有效硅含量的实验条件进行了研究。氟硅酸钾容量法能够准确、快速、简便测定硅肥中有效硅含量。推荐沉淀冷却时间应控制在30min以上;沉淀的洗涤温度应控制在15℃以下;滴定指示剂可选用酚酞;通过对氟硅酸钾分析纯的水解,验证此方法水解完全。     

COMPUTING POLARIZATION CURVES FOR THE ROTATING DISK ELECTRODE BY ORTHOGONAL COLLOCATION

Concentration and potential profiles in the mass-transfer boundary layer adjacent to a rotating disk electrode may be computed approximately by the method of orthogonal collocation. Because the method lends itself to the iterative solution of nonlinear problems, it can handle nonlinear electrode kinetics expressions in the boundary conditions as well as migration and homogeneous reaction terms in the transport equations. Calculation of the current density at various applied potentials generates theoretical polarization curves.

This paper outlines the formulation of the collocation method and presents sample results for the effect of migration on current in a ternary electrolyte, for concentration overpotential calculations, and for simulated polarization curves with multiple electrode reactions and with coupled homogeneous reactions. Although the treatment presented here is limited to the one-dimensional, steady-state model of the rotating disk, it can be generalized to solve multidimensional problems.