Determination of calcium and magnesium in the Solanaceae plant by near infrared spectroscopy combined with interval combination optimization algorithm

Determination of the content of inorganic nutrients was done as part of a project to improve crop yield by use of fertilizers. Near-infrared spectroscopy coupled with interval combination optimization was used to determine the inorganic nutrients of calcium and magnesium in the Solanaceae plant. Interval combination optimization was employed to choose effective intervals with the merit of assigning smaller weights to less significant variables. Compared with full spectrum partial least squares regression, interval combination optimization improved the predictive accuracy and precision for both calcium and magnesium. The result was a high predictive ability for calcium, with a root mean squared error prediction of 0.159%, and for magnesium, with a root mean squared error prediction of 0.064%. In this study, the superiority of interval combination optimization over full spectrum partial least squares was shown in the aspects of effective variables and accurate results. Near-infrared spectroscopy combined with interval combination optimization was efficient for the determination of inorganic nutrients, calcium and magnesium, in the Solanaceae plant.     

Monitoring insect pest infestation via different spectroscopic techniques

Nowadays, monitoring and observing insect pest populations is a major and crucial issue in agriculture, especially for crop protection. Spectroscopic techniques are well recognized for detecting and monitoring insect pests in the field and also the internal quality of fruit. There are several spectroscopic techniques with specific characteristic features, including mass spectrometry, ultraviolet–visible spectroscopy, infrared spectroscopy, and nuclear resonance spectroscopy. Nevertheless, limitations and complexity are the constraints of these technologies. In this paper, the spectroscopic and imaging spectroscopic techniques are discussed, compared, and investigated, namely fluorescence light detection and ranging (LIDAR) to study the fluorescence of diverse types of planthopper (Hemiptera) and moth (Lepidoptera), visible and near-infrared (Vis/NIR) spectroscopy to detect internal insect-infested jujubes, NIR spectroscopy to determine spectral properties of oil palm bagworms, hyperspectral transmittance image for detecting insect-damaged vegetable soybeans, and remote sensing measurement to detect bagworm infestation in oil palm plantations. These techniques are found to be reliable methods for better monitoring of insect pest movement in the harvested plant and in the ground, for the detection of insect-damaged vegetable soybeans and internal insect infestation in jujubes, and for the determination of oil palm bagworm spectral properties.     

基于MC-UVE、GA算法及因子分析对葡萄酒酒精度近红外定量模型的优化研究

对葡萄酒酒精度偏最小二乘（Partial least squares,PLS）回归模型进行优化研究。使用近红外光谱仪采集葡萄酒样本的光谱数据,用于建立酒精度定量模型,实现在线快速检测。通过蒙特卡罗无信息变量消除（Monte Carlo uninformative variable elimination,MC-UVE）和遗传算法（Genetic algorithm,GA）进行变量选择,基于被选择的变量分别进行PLS和因子分析（Factor analysis,FA）,建立回归模型。结果表明,MC-UVE-GA-FAR模型预测集相关系数（R²）为0.946,预测均方根误差（Root mean square error of prediction,RMSEP）为0.215,效果优于MC-UVE-GA-PLS模型。与基于全范围光谱所建PLS回归模型相比,模型效果有所提升,而且模型所选变量个数仅为6,极大地简化了模型。MC-UVE和GA算法与FA分析结合可以实现模型的优化。     

Extraction and application of natural pigments for fabrication of green dye-sensitized solar cells

Four dye-sensitized solar cell devices are designed and fabricated based on natural dyes extracted from Celosia Cristata, Saffron, Cynoglossum, and eggplant peel, as photosensitizers. The UV–vis technique has been served to determine maximum absorption of natural extract and pre-dyed photoanode. The Fourier transform infrared (FT-IR) was employed to cover the presence of functional groups. The cyclic voltammetry method has been employed to assess the possibility of charge transfer from dried natural dyes to the photoelectrode. The performance of natural-based dye-sensitized solar cells is determined subsequently. The highest power conversion efficiency was ca. 1.38%, which belonged to Celosia Cristata extract. The devices were examined for higher efficiencies, individually, co-sensitized arrangement and/or in tandem with each other.     

PbSe量子点近红外光源的CH_4气体检测

研制了一种新型的PbSe量子点近红外光源,其光致发光谱较窄,能有效匹配气体的红外吸收峰。采用配位溶剂法合成出5.1 nm的PbSe量子点,并将其沉积到Ga N芯片上(沉积厚度为165.5μm),经过紫外光照处理和固化后制成了光致发光的近红外光源。该光源第一激子吸收峰位于1 592 nm,光致发光峰位于1 665 nm,其发射光谱包含了1 625~1 840 nm之间的CH_4气体的全部的吸收谱。利用其进行CH_4气体浓度检测实验,结果表明,系统的检测下限可以达到100×10~(-6),检测误差为2%。这种由PbSe量子点近红外光源构成的新型检测系统具有低功耗、低成本和高效能等优点,将其应用在气体检测中时可以略去滤光片,其在红外气体检测领域中有着较广阔的应用前景。     

荧光染料超薄层对有机电致发光器件发光光谱的影响

采用在主体材料上蒸镀一层超薄层的方法,研究了三种有机小分子荧光染料dimethylquinacridon(DMQA)、4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethy ljulolidyl-9-enyl)-4-pyran(DCJTB)和5,6,11,12-tetraphenylnaphthacene(Rubrene)的浓度效应对有机电致发光器件(OLED)电致发光光谱的影响。结果表明,与常规掺杂器件相比,染料超薄层器件的光谱中出现了微弱的主体材料的发光峰,浓度猝灭现象更为明显。三种染料的浓度猝灭程度从高到低依次为DMQA、DCJTB和Rubrene。同时,我们使用此三种染料配制了溶液,测试了它们在不同浓度下的光致发光光谱强度,进一步探讨了掺杂剂浓度猝灭强弱与器件的发光光谱特性的关系。     

利用光谱数据快速检测土壤含水量的方法研究

应用美国ASD公司的FieldSpec HandHeld型可见/近红外光谱仪获得了52份不同含水量土壤的可见/近红外漫反射光谱数据,并通过实验测定了各土壤样本的含水量值,运用相关系数法寻找出了光谱对于土壤水分的敏感波段,然后利用单一敏感波段处的光谱数据建立了一元回归模型, 并检测了土壤含水量。实验结果表明, 该模型对土壤水分的检测效果比较好,模型的预测相关系数r为0.966 5,预测均方根误差RMSEP为0.012 1,为快速、准确检测土壤含水量提供了一条新的途径。     

杂环偶氮染料薄膜的全息光存储

采用含杂原子的偶氮染料TADEB、DMTAM、DMTAA和DMTAMB掺杂高分子聚合物PMMA制成薄膜,利用四波混频全息光路系统,研究了它们的全息光存储性质。实验结果显示DMTAA样品的衍射效率最高,可达到22%,是一种存储性能较为优良的永久性全息光存储介质材料。     

反射式血氧饱和度检测方法的研究

近红外光谱技术可实现组织中血氧代谢的实时无损伤在体测量, 在生物医学领域得到了广泛应用。 本文利用红光、红外光双光束对指尖进行了基于反射式原理的血氧饱和度(SPO2)检测。通过改变入射光的强度, 并在距入射光1.5cm处采集其反射信号, 观察光强变化对光学体积描记（PPG）信号的影响。实验表明在入射光强不同时, 光到达生物组织层次不同, 所得信号幅度、信噪比都不同。以此提出改变光强法来检测组织不同层次的血氧饱和度。     

Anchoring of Fluorophores to Plasma-chemically Modified Polymer Surfaces and the Effect of Cucurbit[6]uril on Dye Emission

Polypropylene supports were functionalized by plasma-deposition of polymeric allylamine layers. The surface amino groups generated were wet-chemically reacted with xanthene dyes resulting in fluorescent polymer films. The effect of polymer-attachment of the dyes on their emission features was studied fluorometrically and different methods were tested to improve the fluorescence properties of the films. Modification with cucurbit[6]uril (CB6) yields a moderately enhanced fluorescence as well as an improved photostability. The observed effect is most likely due to CB6-induced rigidization of the linker molecules which seems to reduce fluorescence quenching dye–dye and fluorophore–surface interactions.