高光谱成像在食品质量评估方面的研究进展与应用(一)

近年来频发的国内食品质量与安全问题受到全社会的高度重视。因此,需要采用现代化检测技术快速、准确获取食品品质和安全信息。高光谱成像技术是一项将光谱与成像科学相结合的光学分析技术。通过同时获取食品的光谱和空间图像信息,高光谱成像技术能够快速、无损获取食品的品质信息及其空间分布,从而实现食品内外部品质信息的全方位检测,因此在食品安全检测应用领域具有巨大潜力。本文介绍了高光谱成像技术的基本原理,并综述了其在肉类品质检验方面的研究进展。     

组态软件及可编程控制器在造纸废水处理中的应用

针对一体化反应器处理造纸废水提出了运用自动化控制技术取代人工操作，在此基础上构建了造纸废水处理自动控制系统。该系统以工业控制机为上位机，PLC为下位机，辅以相应的监测仪器和采集模块，通过组态软件MCGS的管理和BP网络预测控制模型的挂接，完成实验室条件下造纸废水处理的自动控制，为进一步研究造纸废水处理自动控制提供可行途径。     

The influence of nitrogen incorporation on the optical properties of anodic Ta2O5

Anodic oxides were grown on sputter-deposited Ta in different aqueous solutions. A photoelectrochemical investigation was performed in order to estimate the band gap of the films as a function of the anodizing bath composition and formation voltage, i.e. thickness. Photoelectrochemical results provided evidence of sub-band gap photocurrent for films formed in a bath containing ammonium ions at pH 9. Elemental depth profiles obtained by glow discharge optical emission spectroscopy revealed the presence of nitrogen species in the outer part of the anodic films, which is bonded to Ta according to XPS analysis. A mechanism of nitrogen incorporation is proposed in order to account for the pH dependence of film composition.     

Chemical composition and corrosion protection of silane films modified with CeO2 nanoparticles

The present work aims at understanding the role of CeO₂ nanoparticles (with and without activation in cerium(III) solutions) used as fillers for hybrid silane coatings applied on galvanized steel substrates.The work reports the improved corrosion protection performance of the modified silane films and discusses the chemistry of the cerium-activated nanoparticles, the mechanisms involved in the formation of the surface coatings and its corrosion inhibition ability.The anti-corrosion performance was investigated using electrochemical impedance spectroscopy (EIS), the scanning vibrating electrode technique (SVET) and d.c. potentiodynamic polarization. The chemical composition of silanised nanoparticles and the chemical changes of the silane solutions due to the presence of additives were studied using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), respectively.The NMR and XPS data revealed that the modified silane solutions and respective coatings have enhanced cross-linking and that silane-cerium bonds are likely to occur.Electrochemical impedance spectroscopy showed that the modified coatings have improved barrier properties and the SVET measurements highlight the corrosion inhibition effect of ceria nanoparticles activated with Ce(III) ions. Potentiodynamic polarization curves demonstrate an enhanced passive domain for zinc, in the presence of nanoparticles, in solutions simulating the cathodic environment.     

Pd/Ce0.6Zr0.4O2/Al2O3 as advanced materials for three-way catalysts: Part 1. Catalyst characterisation, thermal stability and catalytic activity in the reduction of NO by CO

Pd-loaded Ce_0.6Zr_0.4O₂ solid solutions supported on Al₂O₃ are investigated as catalysts for the reduction of NO by CO. The attention is focused on the role of the Ce_0.6Zr_0.4O₂ and of the Pd dispersion on the catalytic activity. The system shows a very high activity below 500 K, which is almost independent on the Pd dispersion. The high activity is attributed to a promoting effect of the Ce_0.6Zr_0.4O₂ on the NO conversion. Investigation of the influence of high temperature treatments disclosed a thermal stabilisation of both Ce_0.6Zr_0.4O₂ and Al₂O₃ in the Ce_0.6Zr_0.4O₂/Al₂O₃ system.     

Application of near infrared spectroscopy for the rapid determination of antioxidant activity of bamboo leaf extract

This study was carried out to evaluate the feasibility of using near infrared (NIR) spectroscopy for determining three antioxidant activity indices of the extract of bamboo leaves (EBL), specifically 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), and 2,2′-azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS). Four different linear and nonlinear regressions tools (i.e. partial least squares (PLS), multiple linear regression (MLR), back-propagation artificial neural network (BP-ANN), and least squares support vector machine (LS-SVM)) were systemically studied and compared in developing the model. Variable selection was first time considered in applying the NIR spectroscopic technique for the determination of antioxidant activity of food or agricultural products. On the basis of these selected optimum wavelengths, the established MLR calibration models provided the coefficients of correlation with a prediction (r_pre) of 0.863, 0.910, and 0.966 for DPPH, FARP, and ABTS determinations, respectively. The overall results of this study revealed the potential for use of NIR spectroscopy as an objective and non-destructive method to inspect the antioxidant activity of EBL.     

α-ALDC产生菌的抗性标记与融合条件初探

利用青霉素和链霉素分别对α-ALDC产生菌枯草芽孢杆菌3226-5、V-20进行抗药性标记，筛选得到稳定的青霉素抗性标记株P-67和链霉素抗性标记株S-17，并以P-67和S-17为融合的亲本对其原生质体融合条件进行了初探。     

细菌纤维素合成菌株发酵条件的考察

菌株QAX0 2 1 9# 进行液态发酵可产生不溶性的凝胶膜 ,通过纤维素酶水解等实验确定其发酵产物为纤维素 ,同时研究了乙醇、溶氧含量、培养方式以及接种量对菌体合成纤维素的影响。结果为 :以 8%接种量 ,在发酵培养基中添加一定量的乙醇 ,可显著提高纤维素产量     

新型表面活性剂柠檬酸单酯的溶液性能研究及其在凝胶油中的应用

凝胶油不仅在功能食品中得到广泛应用,而且在药物制剂、化妆品领域也有重要应用前景。本文通过直接酯化法合成了两种柠檬酸单酯,并对其作为凝胶因子性能进行了研究。利用表面张力仪、电导率仪以及动态光散射仪等方法对两种柠檬酸酯的溶液聚集行为和胶束形成热力学进行了分析。结果表明,25℃下,柠檬酸月桂醇单酯和柠檬酸异癸醇单酯的临界胶束浓度分别为3.30mmol/L和6.40 mmol/L。同时,研究了离子强度对胶束形成过程的影响,结果表明,无机盐不仅影响胶束聚集数,而且使得柠檬酸异癸醇单酯的胶束尺寸降低约100 nm,柠檬酸月桂醇单酯的胶束尺寸降低约200 nm。凝胶油性能研究结果表明,最低凝胶浓度为7%,溶胶-凝胶转变温度为45~53℃之间,两种柠檬酸酯均能与植物油形成凝胶。生物相容性研究结果表明,两种柠檬酸酯在浓度为200mg/L时对微生物生长没有显著影响,具有良好的生物相容性。     

利用有机凝胶因子提高花生酱稳定性的工艺研究

使用紫虫胶作为有机凝胶因子制备稳定型花生酱,并对其工艺条件进行优化。以析油率为指标,紫虫胶添加量、加热温度、加热时间和冷却温度为因素变量,进行响应面优化试验,得到了最优工艺条件,并进行了花生酱感官评鉴。结果表明,紫虫胶添加量为3.2%(w/w)、加热温度为90 ℃、加热时间为40 min、冷却温度为1 ℃时,制得的有机凝胶花生酱最稳定,此时析油率仅1.24%。在最优工艺条件下制备的有机凝胶花生酱与商品花生酱相比,析油率更低,感官品质更好。