基于红外衰减全反射法的高弹改性沥青组分析出表征

通过测试2种不同高弹改性沥青的宏观性能发现,高弹1#改性沥青的延度和针入度随时间推移明显降低,软化点呈升高趋势,-10℃低温弯曲应变显著下降,而高弹2#改性沥青宏观力学性能并没有发生明显衰变;采用红外衰减全反射法(ATR)结合红外光谱定量分析法对2种不同高弹改性沥青的组分析出问题进行了研究,发现高弹1#在60℃的温度下随时间延长逐渐从改性沥青表面析出,且析出迁移量逐渐增加,而高弹2#基本不发生组分析出,其组分抗迁移能力优于高弹1#。证明高弹1#改性沥青宏观性能衰变的原因是由于高弹改性剂随时间延长逐渐析出至沥青表面所致。

氮化物荧光粉的制备及稳定性研究

采用高温固相法可以制备得到Ca1-xSrxAlSiN3:0.02Eu^(2+)系列荧光粉。通过X射线衍射仪、扫描电子显微镜和稳态荧光光谱仪对样品的物相、晶体形貌和发光性能进行表征,可以分析不同Sr^(2+)和Ca^(2+)含量的荧光粉样品的晶体颗粒形貌和激发发射光谱的差异。研究发现,随着Sr^(2+)含量的增多,荧光粉样品的晶体形貌逐渐变为长条形,发射光谱逐渐蓝移。对荧光粉样品进行蒸煮,对比蒸煮前后的发射光谱与扫描电镜照片,经过蒸煮后的样品颗粒表面变得粗糙,出现裂缝,发射峰蓝移,发射强度降低。同时,随着荧光粉中Sr^(2+)含量的增多,样品蒸煮后的表面劣化程度和发射衰减程度都有明显的增强,这表明Sr^(2+)含量会影响荧光粉的稳定性,而且Sr^(2+)比Ca^(2+)更易被氧化。

ATR-FTIR法测定汽油中碳酸二甲酯的质量分数

利用液体衰减全反射-傅里叶变换红外光谱法（ATR-FTIR）快速测定汽油中碳酸二甲酯的质量分数，并且利用朗伯-比尔定律对其进行定量分析。结果表明，当碳酸二甲酯质量分数为0.5%~10.0%时，该方法具有良好的线性关系，检出限为0.15%，回收率为101.4%~118.4%，相对标准偏差低于1%。该方法具有简单、准确、快速、重复性好、成本低的优点。

Enhancement of heat radiative characteristics of coatings by ultra-attenuation

The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.

Behaviors of field emitters under pulsed voltages

In this paper we described our study of the behaviors of field emitters driven by square-wave voltages. We observed phenomena under pulsed voltages that generally do not manifest themselves under direct-current voltages. We interpreted these phenomena with the cathode and anode combined treated as equivalent to a resistor and a condenser in series connection. First,because of the delay caused by the charging process of the condenser, the waveform of the voltage across the cathode-anode gap was remarkably distorted. Second, the resistor led to considerable attenuation in field emission, which was clearly observable within each pulse and became more dramatic with increasing repetition frequency of the pulses. Furthermore, the field emission currents under direct-current voltages were lower than those under pulsed voltages. This disparity is attributed to rising resistance in the circuit with rising temperature. We also discussed the restrictions that the waveform distortion and current attenuation could impose on potential field emitter applications.