微流蒸发光散射检测器的研制及评价

构建了适用于纳升级到微升级流量的毛细管分离体系的微流蒸发光散射检测器(μELSD),实现了其与毛细管液相色谱(eLC)的联用.对雾化器孔径和雾化毛细管内径、蒸发管内径和长度、光散射池尺寸、雾化毛细管位置和辅助载气流量等参数进行了优化.在最优条件下,微流蒸发光散射检测器检出限为直接进样葡萄糖1 ng(S/N＞ 10),线性范围0.01～1.0 μg,重复性好,峰面积RSD(n=6)为0.4％,峰高RSD(n=6)为0.3％.本检测器已成功应用cLC-μELSD平台,使用C18毛细管色谱柱(内径250 μm),0.1％甲酸铵溶液(pH 4.5)-甲醇(60∶40,V/V)为流动相,分离检测了3种常用甜味剂,表明本研究构建的系统可以应用于实际分离检测中,具有分析时间快、溶剂消耗量少、样品需求量小的优点.     

Monitoring the reaction between AlCl_3 and o-xylene by using terahertz spectroscopy

Terahertz time-domain spectroscopy(THz-TDS)is used to study the interaction between AlCl3and o-xylene in a temperature range from 300 K to 368 K.For comparison,the three isomers of o-,m-,and p-xylene are measured by using THz-TDS.The o-xylene carries out isomerization reaction in the presence of catalyst AlCl3.The absorption coefficient of the mixed reaction solution is extracted and analyzed in the frequency range from 0.2 THz to 1.4 THz.The temperature dependence of the absorption coefficient,which is influenced by both the dissolution of AlCl3and the production of the two other isomer resultants,is obtained,and it can indicate the process of the isomerization reaction.The results suggest that THz spectroscopy can be used to monitor the isomerization reaction and other reactions in chemical synthesis,petrochemical and biomedical fields.     

Fast lateral photovoltaic effect in ferroelectric LiNbO_3 single crystals

We report the fast lateral photovoltaic effect in pure congruent LiNbO3 crystal induced by pulsed laser and continuous wave laser with wavelengths of 355, 532, and 1064 nm. A typical ultrafast photovoltage can be observed on the surface perpendicular to the c axis, With the rise time of 1.5 ns and the full-width at half-maximum of 1-2 ns, when the laser pulse inhomogeneously irradiates on the crystal. The peak open-circuit photovoltages show a linear dependence on the incident laser intensities. The mechanism of the photovoltaic characteristics is proposed.     

Consistency-dependent optical properties of lubricating grease studied by terahertz spectroscopy

The optical properties of four kinds of lubricating greases (urea, lithium, extreme pressure lithium, molybdenum disulfide lithium greases) with different NLGL (National Lubricant Grease Institute of America) numbers were investigated using terahertz time-domain spectroscopy. Greases with different NLGL grades have unique spectral features in the terahertz range. Comparison of the experimental data with predictions based on Lorentz--Lorenz theory exhibited that the refractive indices of each kind of lubricating grease were dependent on the their consistency. In addition, molybdenum disulfide (MoS₂) as a libricant additive shows strong absorption from 0.2 to 1.4 THz, leading to higher absorption of MoS₂-lithium grease than that of lithium grease.     

Monitoring the reaction between AICl3 and o-xylene by using terahertz spectroscopy

Terahertz time-domain spectroscopy （THz-TDS） is used to study the interaction between AlCl3 and o-xylene in a temperature range from 300 K to 368 K. For comparison, the three isomers of o-, m-, and p-xylene are measured by using THz-TDS. The o-xylene carries out isomerization reaction in the presence of catalyst AlCl3. The absorption coefficient of the mixed reaction solution is extracted and analyzed in the frequency range from 0.2 THz to 1.4 THz. The temperature dependence of the absorption coefficient, which is influenced by both the dissolution of AlCl3 and the production of the two other isomer resultants, is obtained, and it can indicate the process of the isomerization reaction. The results suggest that THz spectroscopy can be used to monitor the isomerization reaction and other reactions in chemical synthesis, petrochemical and biomedical fields.     

在太赫兹波段的开口共振环的不同开口形状对透过率频谱的影响

通过对不同开口形状的太赫兹(THz)波段共振环(SRR)的有限时域差分(FDTD)模拟,发现了SRR不同开口形状在发生共振时对开口间距的平均值具有相同的透过率频谱分布的均值效应;并且观察到了在开口边缘很尖的特殊条件下,SRR开口将出现导通现象.此结果可为今后SRR开口工艺设计与质量控制提供参考,也可为SRR工作机理的进一步分析研究提供有关的依据. 关键词： 太赫兹 开口共振环 开口形状 FDTD     

基于Vague集的第三方物流客户满意度评价方法研究

首先分析了已有研究中对第三方物流客户满意的评价指标体系,接着将Vague集评价思想引入到该领域中,借助偏差函数确定各个指标的权重,通过正负理想解的定义,确定待评价对象与正负理想解之间的距离,最后借助指标函数的定义得到了各个方案的评价值.研究成果对物流企业改善服务,提高市场竞争力具有一定的促进作用.     

微流蒸发光散射检测器与毛细管液相色谱的联用及其在银杏叶提取物分析中的应用

将微流蒸发光散射检测器( μELSD)与毛细管液相色谱(cLC)联用,应用于中药银杏叶提取物及其分散片制剂的分离检测领域。首先对 μELSD仪器参数进行优化。通过调节漂移管温度与载气流量,提高了分析物的响应,并减小了噪声。然后,搭建了cLC-μELSD分离检测平台,其相对常规LC可大大减小实验试剂消耗。流动相A为0.05%(体积分数,下同)三氟乙酸(TFA)水溶液,流动相B为含0.05% TFA的甲醇溶液。最优的洗脱梯度条件为:0~10 min,5%B~25%B;10~25 min,25%B~38%B;25~35 min,38%B;35~40 min,38%B~42%B;40~55 min,42%B~50%B。银杏叶提取物和复杂中药制剂银杏叶提取物分散片都得到了较好的分离,并在其中鉴定到紫外波段几乎无吸收的重要内酯类活性成分白果内酯以及银杏内酯A、B和C。测定了不同厂家银杏叶提取物中萜类内酯洗脱时间的相对标准偏差,结果均不大于2.42%,表明该体系在目标物的分析上具有良好的重现性。实验证明所建立的cLC-ELSD体系在复杂中药体系的分离检测中有良好的应用性。     

Ultraviolet laser-induced voltages in LaSrAlO4 single crystal

Laser-induced ultrafast photovoltaic effect is observed in LaSrAlO4 single crystal at ambient temperature without any applied bias. An open-circuit photovoltage is obtained when the wafer is irradiated by a 248-nm-KrF laser pulse of 20 ns duration. The response time and full width at half maximum of the photovoltage pulse are 6 ns and 19 ns, respectively, indicating that LaSrAlO4 single crystal has potential application in ultraviolet detector.