三波段法计算机配色的研究

本文分析了三刺激值方法和全光谱方法计算机配色的优缺点,建立了三波段法计算机配色系统。这种方法,根据人眼标准观察者三刺激值的最大值分别落在可见光范围内的红区、绿区和蓝区的特点,把可见光范围的光谱均分为三个波段,在每个波段上,应用三刺激值配色,对三个波段上的色差又采用最小二乘法方法优化,最终确定所需要的配方。实验表明,三波段法配色具有三刺激值配色和全光谱匹配两种方法的优点。     

太赫兹科学技术的发展与实验室建设

近年来,太赫兹科学技术受到了世界各国政府、企业和科技部门的高度重视,得到了迅猛的发展,这不仅是因为太赫兹波本身具有独特的性质,更因为太赫兹科学技术给人们展示了广阔的应用前景。本文首先对太赫兹波及其有关特性进行介绍,说明太赫兹科学技术具有重要的学术价值和重大的应用前景。其次,重点说明太赫兹辐射源和探测技术的发展,进而介绍我们实验室在太赫兹波谱与成像方面所开展的一些工作。最后,结合太赫兹光电子学重点实验室的建设,介绍我们实验室正在开展的研究工作。     

Protic Ionic Liquids with Ammonium Salts as Lubricants for Magnetic Thin Film Media

The newly synthesized perfluoropolyether (PFPE) whose terminal group is an ammonium salt with a carboxylic acid has better frictional and anti-corrosion properties when compared to the conventional PFPEs. The friction is almost independent of the PFPE structure, but depends on the amine structures. This modified PFPE uniformly covers the magnetic surfaces; this is why it not only reduces the friction, but also has an effect on the corrosion resistance.     

星载差分吸收光谱仪摆镜控制系统设计

针对差分吸收光谱仪搭载于地球同步轨道卫星时对地成像的要求,设计了一种扫描摆镜转动控制系统。从摆镜控制结构设计、控制电路设计两个方面阐述了摆镜系统的方案。摆镜系统受载荷主控器控制,接收控制指令并回传当前摆镜位置状态,通过LMD18200驱动芯片进行功率输出,由步进电机和谐波减速器构成的驱动器驱动摆镜转动,编码器读取摆镜角度信息。给出了PWM(Pulse Width Modulation)波占空比的测定办法,并提出通过回转到成像起始点之前的方式,消除回程误差对成像区域步距不确定性的影响。实验结果表明该系统的步距角均值偏差小于1″,最大偏差小于5″,标准偏差小于2″。该光谱仪摆镜控制系统满足步距精度指标要求。     

FT-NIR光谱法测定烟叶中钙、镁元素

采用傅立叶变换近红外光谱仪对220个烟叶样品进行光谱采集,用偏最小二乘法建立钙元素和镁元素的校正模型,并通过剔除异常值优化模型。模型经过优化后的结果:钙元素近红外模型的R2值、SEE值、SEP值和RPD值分别为98.39%、0.11、0.15和5.7,模型因子数为14;镁元素近红外模型的R2值、SEE值、SEP值和RPD值分别为89.39%、0.04、0.06和2.2,模型因子数为14。用F检验和t检验说明近红外模型的预测值和化学值之间没有明显差异。结果表明,近红外光谱法可用于烟叶中的钙、镁元素的同时快速定量测定。     

Preliminary study on the application of visible–near infrared spectroscopy and chemometrics to classify Riesling wines from different countries

Visible (VIS) and near infrared (NIR) spectroscopy combined with chemometrics was used in an attempt to classify commercial Riesling wines from different countries (Australia, New Zealand, France and Germany). Commercial Riesling wines (n = 50) were scanned in the VIS and NIR regions (400–2500 nm) in a monochromator instrument, in transmission mode. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and stepwise linear discriminant analysis (SLDA) based on PCA scores were used to classify Riesling wines according to their country of origin. Full cross validation (leave-one-out) was used as the validation method when classification models were developed. PLS-DA models correctly classified 97.5%, 80% and 70.5% of the Australian, New Zealand and European (France and Germany) Riesling wines, respectively. SLDA calibration models correctly classified 86%, 67%, 67% and 87.5% of the Australian, New Zealand, French and German Riesling wines, respectively. These results demonstrated that the VIS and NIR spectra contain information that when used with chemometrics allow discrimination between wines from different countries. To further validate the ability of VIS–NIR to classify white wine samples, a larger sample set will be required.     

基于TDLAS的分布式激光甲烷监控系统研究

结合可调谐激光吸收光谱技术(TDLAS)研究完整分布式激光甲烷监控系统,包括TDLAS监测系统整体架构设计、光源和气体传感器、光电转换、信息采集等部分设计,分析甲烷检测设计难点,并与国内外多监测点的在线气体监测系统比较,说明其具备的优势。     

Growth of silicon carbide nanorods from the hybrid of lignin and polysiloxane using sol-gel process and polymer blend technique

We report here the formation of silicon carbide (SiC) nanorods from organic-inorganic hybrid of the commercially available lignin and sol-gel derived nanosized silica. The SiC nanorods were identified by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface morphology shows the formation of continuous nanorods of diameter in the range of 50-200 nm. The X-ray diffraction (XRD) pattern show peaks at 2θ = 35.5° and 60.2° indicate the formation of β-SiC and a sharp peak at 2θ = 22.1° suggests the presence of unreacted crystalline silica (crystoballite). The characteristic vibration of SiC at 791 cm^− 1 in Fourier transform infrared spectroscopy (FTIR) was also observed.     

Controlled doping of double walled carbon nanotubes and conducting polymers in a composite: An in situ Raman spectroelectrochemical study

The interaction of double wall carbon nanotubes (DWCNTs) and the conducting polymer poly(3,4-ethylenedioxythiphene)/polystyrenesulfonate (PEDOT/PSS) was studied by in-situ Raman spectroelectrochemistry. The mixing of DWCNTs with PEDOT/PSS caused a partial doping of the outer tube of DWCNTs, which was indicated by the relative change of the Raman intensity of the DWCNTs features. On the other hand, the bands corresponding to inner tubes of DWCNTs and to the polymer were almost untouched by assembling both species into a composite. The in-situ Raman spectroelectrochemical experiments have shown that the changes in electronic structure of inner tubes of DWCNTs embedded in PEDOT/PSS matrix are dependent on the doping level. While at the low doping level of the composite, the Raman features of inner tubes of DWCNTs do not change significantly, at high doping level they reflect the changes caused by the applied electrochemical potential similar to those observed in the polymer-free DWCNTs.     

Effect of DC current polarization on the electrochemical behaviour of La2NiO4+δ and La3Ni2O7+δ-based systems

The electrode performance of La₂NiO₄ and La₃Ni₂O₇ as cathode materials for solid oxide fuel cells (SOFC) was analyzed. The study was focused on the electrode polarization resistance of the interfaces formed by the cathodes with Ce_0.8Sm_0.2O_2−δ + 2%Co electrolyte. The study was extended to cathodes based on La₂NiO₄-Ce_0.8Sm_0.2O_2−δ composite and Pt to analyze the effect of changing the electronic and/or ionic transport properties on the electrode interface resistance. The electrode performance was studied in open circuit conditions and with DC current polarization. Important differences in the performance of the pure cathode materials were obtained as function of DC current flux. However, in La₂NiO₄-Ce_0.8Sm_0.2O_2−δ composite the DC current flux produces minor changes in the electrode polarization resistance. The aging process also affects the OCV electrode performance of cathodes based on Pt and pure ceramics, whereas the effect is practically invaluable in La₂NiO₄-Ce_0.8Sm_0.2O_2−δ composite. The electrode performance is higher for the composite cathode compared to pure ceramic electrodes for OCV or for low values of DC polarization. However, the important decrease in the interface resistance obtained for high values of DC current flux for La₂NiO₄ and La₃Ni₂O₇ cathodes increases their electrode performances to values close to those obtained in La₂NiO₄-Ce_0.8Sm_0.2O_2−δ composite. This retains the cathode overpotential with values as low as 140 mV at 750 °C for values of current load of 530 mA cm⁻² for both pure and composite La₂NiO₄-based cathodes. The low cathode overpotential allows to estimate values of power density between 300 and 350 mW cm⁻² at 750 °C for La₂NiO₄, La₃Ni₂O₇ and La₂NiO₄-Ce_0.8Sm_0.2O_2−δ composite, operating with Ce_0.8Sm_0.2O_2−δ + 2%Co electrolyte, with 300 μm in thickness, and a Ni-Ce_0.8Sm_0.2O_2−δ cermet anode with H₂ as fuel.