稀土在降低电解渗硼层脆性中的作用

采用熔盐电解法分别对45钢试样进行了渗硼和稀土-硼共渗处理,用三点弯曲声发射试验测定其脆性。对比实验结果表明,稀土元素的加入可大大降低电解渗硼层的脆性。通过裂纹形貌观察、稀土元素在硼化物和α-Fe中的固溶分析以及对Fe_2B点阵常数的影响,探讨了稀土元素对降低电解渗硼层脆性的原因。     

N-(1, 3, 4-噻二唑-2-基)-N′-芳酰基脲的合成及其生物活性

N-(1;3;4-噻二唑-2-基)-N′-芳酰基脲的合成及其生物活性;噻二唑;芳酰基脲;合成;生物活性;植物生长调节剂     

全硅ZSM—5分子筛填充柱的制备及应用

合成了全硅ZSM-5分子筛，制备了一种新型的全硅ZSM－5分子筛填充柱，成功地在室温下进行了O2，N2分离，并利用物化色谱法，准确而快速地测定了O2,N2在全硅ZSM－5分子筛填充柱上的吸附热。     

2′,7′-二氯荧光素荧光光谱法测定食盐中的IO-3含量

在 pH 1.4～3.4的 H2SO4 介质中,IO-3 与过量 I- 反应生成 I2,I2 与2′,7′-二氯荧光素反应,引起荧光猝灭,体系荧光强度降低,由此建立了荧光光谱法测定食盐中 IO-3 含量的新方法.体系的荧光发射波长λem=515 nm,体系的荧光强度降低值△IF 与 IO-3含量在0.40～2.00 μg·mL-1 之间呈良好的线性关系,回归方程为△IF＝12.675ρ-3.499(ρ的单位μg·mL-1),相关系数r=0.998 0.该法灵敏度高,选择性好,用于食盐中 IO-3 的含量的测定,结果满意.     

硫羟乳酸作为络合滴定掩蔽剂的研究

本文系统地研究了硫羟乳酸在络合滴定中的掩蔽性能。发现在ｐＨ３．０用ＥＤＴＡ滴定了Ｔｈ＾４＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋，Ｂｉ＾３＋，Ｂｈ＾２＋和Ｃｕ＾２＋。在ｐＨ５．５滴定Ｙｂ＾３＋，Ｌａ＾３＋或Ｃｅ＾３＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋，Ｂｉ＾３＋，Ｈｇ＾２＋，Ｃｕ＾２＋和Ｃｒ＾３＋，在ｐＨ１０．０滴定Ｍｇ＾２＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋     

Generalized Thermo Vacuum State Derived by the Partial Trace Method

By virtue of the technique of integration within an ordered product of operators, we present a new approach for deriving the generalized thermo vacuum state which is simpler in form than that obtained from the Takahashi -Umezawa method, using this new approach, the thermo field dynamics can be developed. Applications of the new state are discussed.     

圆锥曲线焦点弦与相应准线的关系

文[1] 探讨了抛物线焦点弦与其准线之间的性质,耐人寻味.笔者经过探究,圆锥曲线焦点弦与焦点相应准线存在如下一些性质.……     

Polarization-Independent All-Fibre Comb Filter with Dynamically Halved Channel Spacing

A polarization-independent all-fibre comb filter with dynamically halved channel spacing is proposed. The filter is based on high-birefringent fibre Sagnac interferometers and its channel spacing can be dynamically halved by turning on an optical switch. A good agreement between the numerical simulation and the experimental results is achieved.     

Structural and Upconversion Fluorescence Properties of Er^3＋／Yb^3＋-Codoped Lead-Free Germanium-Bismuth Glass

We study the structural and infrared-to-visible upconversion fluorescence properties of Er^3 /yb^3 -codoped leadfree germanium-bismuth glass. The structure of lead-free germanium-bismuth-lanthanum glass is investigated by peak-deconvolution of F~aman spectroscopy. Intense green and red emissions centred at 525, 546, and 657nm,corresponding to the transitions ^2H11/2 → 4I15/2, ^4S3/2 → 4I15/2, and 4F9/2 → 4I15/2, respectively, are observed at room temperature. The quadratic dependence of the 525, 546, and 657nm emissions on excitation power indicates that a two-photon absorption process occurs under 975nm excitation.     

CuNiAl形状记忆合金相变和裂纹形核及扩展的原位研究

采用扫描电子显微镜(SEM)和透射电镜(TEM)原位拉伸技术研究了形状记忆合金CuNiAl应力诱发马氏体相变以及它与裂纹形核、扩展的交互作用.结果表明,裂尖应力集中能诱发层错及不同形态的马氏体.在TEM中加载时,裂纹前方的马氏体能从一种形态转变为另一种形态,甚至逆变成母相.微裂纹可以在马氏体/母相界面以及两个马氏体的交汇处形核.当裂纹扩展一段距离,裂尖应力集中足够大时,可产生滑移带,这时微裂纹更容易沿滑移带形核.