基于RGB颜色信息聚类的光谱反射率重建

针对光谱反射率研究中因训练样本数据量大造成的冗杂等问题，提出了一种基于RGB信息进行聚类的样本分类方法。首先对颜色进行聚类并确定聚类个数，后对每一类光谱反射率使用BP神经网络分别进行重建。对于实验结果，使用ΔE₀₀、均方根误差（RMSE）以及适应度系数等标准进行评价，同时与主成分分析算法进行对比。从实验分析可得出，在聚类数目为7时光谱反射率重建效果最好，这时的平均CIE2000的色差为0.836，平均RMSE为0.0149，平均适应度系数为99.82%，并且，在最后对重建色差较大的色块进行了优化处理。实验证明，颜色聚类方法可以很好的应用于光谱反射率重建。     

红外光谱技术在食品检测中的应用

红外光谱在食品检测研究中的应用较为广泛, 具有样品前处理简单、操作方便、易于推广, 且对气体、液体和固体样品均可准确检测等优点, 表现出良好的发展前景。本文概述红外光谱技术的检测基本原理和化学计量学在红外光谱技术中的应用, 在简要对比常用检测分析方法的优缺点基础上, 对红外光谱技术在食品鉴伪、品质研究、有害物检测和成分分析等领域的研究进展进行了综述, 详细介绍该技术与化学计量学结合评价食品品质的应用实例, 同时提出目前研究存在的局限性, 并陈述改进建议, 且对该技术在食品检测研究的未来发展方向作出展望, 以期为该技术的深入研究提供参考。     

煤与高岭石表面性质对凝聚过程的影响机制

煤泥水中含大量高岭石等黏土矿物，为其絮凝沉降带来较大的困难。为明确矿物性质对凝聚过程的影响机制，在应用扩展的DLVO理论计算煤和高岭石颗粒间作用力的基础上，采用聚焦光束反射测量仪监测了CaCl2用量为4.50 mmol/L时20 g/L的煤和高岭石的悬浮液在60, 100和150 r/min的搅拌转速下的凝聚过程。结果表明，颗粒间的静电作用力在颗粒表面间距2?200 nm范围内起主导作用，高岭石的电负性较大，在凝聚过程中更难发生靠近和碰撞；较高的转速可为颗粒提供较大的动量，有利于提高碰撞频率，缩短完成凝聚所需时间，实验条件下，煤和高岭石的凝聚时间分别由74和123 s缩短至47和89 s。疏水性作用力在颗粒表面间距小于2 nm的范围内起主导作用，决定了颗粒的黏附效率；煤因强疏水性，在碰撞后更易黏附，且能抵抗更高的流体剪切作用，可由19.32 μm凝聚形成100 μm的大凝聚体，而高岭石则因其亲水性难以得到较大粒度的凝聚体，均小于30 μm。     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.     

基于中红外漫反射光谱技术测定精米中直链淀粉含量的研究

研究了基于傅里叶中红外漫反射光谱(DR-FTIR)技术结合偏最小二乘法(PLS)、主成分分析法(PCR)、经典最小二乘法(CLS)、逐步多元线性回归法(SMLR)快速测定精米中直链淀粉含量。实验选取了161个精米样品作为研究对象,通过光谱预处理,异常值剔除,波谱区间选择对模型进行了优化。结果表明:采用PLS建模,通过多元散射校正,向后区间偏最小二乘法预处理后,所构建的模型效果最优。此时,建模区间为3 800~3 500、3 100~3 000、2 900~2 400、2 300~1 300、1 000~900 cm~(-1),模型相关系数R为0.995 6,校正均方差为0.291,预测均方差为1.23;同时,实验另选了34种精米样品对模型进行了准确性验证。结果显示验证集样品的红外预测值与真实值高度相关,线性拟合方程为Y=0.994X+0.068,相关系数R为0.994 9,说明实验所开发的直链淀粉DR-FTIR模型是有效的,预测结果准确度好,模型稳定性高。     

A spectroscopic method for quick evaluation of tint strength and tint tone of titania (rutile) pigment and factors affecting them

Titanium dioxide (TiO₂) manufacturing industries measure optical properties such as brightness, colour, tint strength, tint tone, gloss, scatter coefficient, and others to ensure the quality of the product. Product characterization and process control generally focus on the optical properties, which determine its quality. In this work, titania rutile pigment with varying tint strength and tint tone is analyzed and a correlation is established between particle size and the optical properties such as tint strength and tint tone. It is observed that optical properties of titania pigment depends on the particle size as well as particle size distribution. A relatively faster evaluation of tint strength and tint tone can be made using the reflectance and particle size measurements. Analytical samples were prepared by ultrasonic dispersion of pigment in water containing calgon as dispersing agent. To verify the accuracy of the method, pigment tint strength and tint tone obtained from this study are compared with those resulting from traditional analysis. The results showed that the new method is viable.     

Design of data feature-driven 1D/2D convolutional neural networks classifier for recycling black plastic wastes through laser spectroscopy

In this study, two types of convolutional neural network (CNN) classifiers are designed to handle the problem of classifying black plastic wastes. In particular, the black plastic wastes have the property of absorbing laser light coming from spectrometer. Therefore, the classification of black plastic wastes remains still a challenging problem compared to classifying other colored plastic wastes using existing spectroscopy (i.e., NIR). When it comes the classification problem of black plastic wastes, effective classification techniques by the laser spectroscopy of Fourier Transform-Infrared Radiation (FT-IR) with Attenuated Total Reflectance (ATR) and Raman to analyze the classification problem of black plastic wastes are introduced. Due to the strong ability of extracting spatial features and remarkable performance in image classification, 1D and 2D CNN through data features are designed as classifiers. The technique of chemical peak points selection is considered to reduce data redundancy. Furthermore, through the selection of data features based on the extracted 1D data with peak points is introduced. Experimental results demonstrate that 2DCNN classifier designed with the help of 2D data feature selection as well as 1DCNN classifier shows the best performance compared with other reported methods for classifying black plastic wastes.     

光度计测定镜质体反射率工作曲线的建立与应用

为了优化配煤,提高镜质体反射率测试精度,以MSP UV-VI2000型光度计为例,介绍了测定镜质体反射率的原理和测试流程。推导出了测定反射率的通用公式和专用公式。对2种公式进行比较发现:专用公式需要校准设备,过程繁琐。通用方法具有普遍适用的特点,其基本步骤为人工读数,做曲线,计算反射率值,绘制直方图。根据公式,分析了工作曲线的最大量程,反射率的分辨能力。重点比较分析了不同斜率的2条光度计工作曲线以及在测试过程中如何选择工作曲线。最后提出了光度计测定镜质体反射率应遵循的原则。     

Non-destructive Determination of High Oleic Acid Content in Single Soybean Seeds by Near Infrared Reflectance Spectroscopy

Soybean [Glycine max (L.) Merr] with increased oleic acid is desirable to improve oxidative stability and functionality of soybean seed oil. Recently, soybean genotypes with high oleic acid (≥70 %) were developed by breeding programs. Efficient and effective identification of high oleic acid soybean genotypes using non-destructive near infrared reflectance (NIR) on whole seeds would greatly enhance progress in breeding programs. The objective of this study was to develop a calibration equation for NIR determination of high oleic acid from single soybean seeds. A total of 600 intact, single F₂ seeds were scanned by NIR. Spectral data were collected between 400 and 2,500 nm at 2 nm intervals. The relationship between NIR spectral patterns of each soybean seed and its oleic acid content was examined. The best predicted equations for oleic acid were selected on the basis of minimizing the standard error of cross-validation and increasing the coefficient of determination. Validation demonstrated that the equations for determining total oleic acid and over 50 % oleic acid content had high predictive ability (r ² = 0.91 and r ² = 0.99, respectively). To validate the newly developed equation, F₂ seeds from a different genetic background were tested. Again, high oleic acid from single soybean seeds was accurately predicted from various genetic backgrounds. Therefore, applying the calibration equations to NIR will be useful to rapidly and efficiently select high oleic acid soybean genotypes in breeding programs.     

太阳能选择性吸收涂层设计及空气高温稳定性测试

使用光学软件TFCalc设计了2种金属陶瓷太阳能选择性吸收涂层,根据反射率曲线,优选出Al–Al2O3复合涂层,并按照设计的最优涂层结构,采用磁控溅射法在铜基体上制备了Al–Al2O3复合涂层。研究了涂层在300°C/3 h热处理前后的结合强度、太阳光反射率和表面形貌。结果表明,经300°C空气高温处理3 h后,涂层临界载荷由11.62 N下降到8.75 N,太阳光谱吸收率由93%(该值与TFCalc模拟结果基本一致)下降到86%。显微分析证实涂层性能下降是由于热处理后,涂层表面不再致密平整所致。