Local charge regulation by doping Li+ in BaGa2O4:Bi3+ to generate multimode luminescence for advanced optical Morse code

In the field of advanced anti-counterfeiting research, it is a hot issue to develop a multimodal anti-counterfeiting material with adjustable luminescence characteristics. Here, persistent luminescent materials of BaGa₂O₄:xBi³⁺ (x = 0-0.02) and BaGa₂O₄:0.005Bi³⁺,yLi⁺ (y = 0.001–0.02) were synthesized by a solid state reaction at high temperature. BaGa₂O₄: Bi³⁺ exhibited a broad blue emission at ～470 nm (transition from [GaO₄]) and a sharp NIR emission at ～710 nm (³P₁→¹S₀ transition of Bi³⁺), upon UV excitation at 250 nm. Incorporation of Li⁺ in BGO: 0.005Bi³⁺ induced the emission color shifting from blue to green. After stoppage of UV excitation, the BGO:0.005Bi³⁺ exhibited white afterglow with emission peaks at the range of 500–700 nm. However, incorporation of Li⁺ leaded to a stronger green afterglow and a weaker NIR afterglow. When the afterglow disappeared, the sample outputted afterglow again after heating processing. The prepared samples exhibited time- and temperature-dependent multimode luminescence, so they were used as components, combined with Morse code to realize multi-modal dynamic anti-counterfeiting. The outcomes in this work indicate that the prepared luminescent materials have broad prospects in advanced anti-counterfeit applications.     

红外辐射联合回火与冷激杀菌技术对胡萝卜粉品质的影响

首先研究不同红外辐射温度(100,110,120℃)及辐射时间(2.5,5,10 min)对胡萝卜粉微生物及品质的影响,然后根据栅栏效应原理研究红外辐射-回火、红外辐射-冷激联合杀菌对胡萝卜粉微生物、色调值、类胡萝卜素含量等品质的影响。结果表明:100℃、10 min的红外辐射处理使细菌和真菌分别降低了1.9 lg(CFU/g)和2.32 lg(CFU/g),110℃、5 min的红外辐射处使细菌和真菌分别降低了1.58 lg(CFU/g)和2.57 lg(CFU/g)。在上述两种处理条件下胡萝卜粉的水分活度从0.238分别降至0.123和0.147,胡萝卜粉中总类胡萝卜素含量从308.8μg/g降至227.8μg/g和238.8μg/g,色差值(ΔE)为9.11和7.89。与红外辐射单独作用相比,联合回火后的处理没有显著影响细菌数目,处理后保持在5.40~5.80 CFU/g,霉菌、酵母数却在处理过程中显著减少,然而减少量较低,总数仍不低于4.5 lg(CFU/g)。红外辐射-冷激联合处理相比红外辐射单独处理,100℃、10 min联合冷激7 d处理可将细菌数量降低0.25 lg(CFU/g),可将霉菌与酵母数量降低0.28 lg(CFU/g),110℃、5 min联合冷激7 d处可将细菌数量降低0.26 lg(CFU/g),可将霉菌、酵母数量降低0.40 lg(CFU/g),且这些处理下胡萝卜粉的色调值、水分活度、类胡萝卜素含量变化不显著。本试验结果表明,红外辐射-冷激处理具有协同效应,且处理过程中胡萝卜粉的色调值及总类胡萝卜素含量不受影响,这为低水分粉体食品红外辐射联合杀菌提供了参考。     

Dendrimer as nanocarrier for drug delivery

Dendrimers are novel three dimensional, hyperbranched globular nanopolymeric architectures. Attractive features like nanoscopic size, narrow polydispersity index, excellent control over molecular structure, availability of multiple functional groups at the periphery and cavities in the interior distinguish them amongst the available polymers. Applications of dendrimers in a large variety of fields have been explored. Drug delivery scientists are especially enthusiastic about possible utility of dendrimers as drug delivery tool. Terminal functionalities provide a platform for conjugation of the drug and targeting moieties. In addition, these peripheral functional groups can be employed to tailor-make the properties of dendrimers, enhancing their versatility. The present review highlights the contribution of dendrimers in the field of nanotechnology with intent to aid the researchers in exploring dendrimers in the field of drug delivery.     

Carbon nanotube–polyaniline composites

The last decade has seen a growing interest in hybrid electrically conducting nanocomposites. This article aims to provide a detailed overview of the present status of research in carbon nanotube–polyaniline (CNT/PANI) composites, from processing to structural and property evaluations. CNT/PANI are synthesized by electrochemical and chemical processing. When chemical methods are used, the main challenge is to obtain processable CNT/PANI in the emeraldine salt (ES) form composites. Stable dispersions of ES–CNT in organic media are prepared using the post doping method, inverse emulsion polymerization, or ex situ polymerizations. On the contrary, stable water dispersions of CNT/ES are prepared using hydrophilization of a preformed CNT/ES composite, direct synthesis of micelle–CNT hybrid templates, interfacial polymerization, covalent functionalization of CNT with a water soluble polymer, or using electrostatic interactions between two oppositely charged ES and CNT aqueous colloids. Moreover, the strategies for the synthesis of ternary CNT/PANI composites incorporating noble metal nanoparticles, metal oxide, or graphene sheets are also presented and analyzed in depth. Finally, we give a review of potential applications, including chemical sensors, capacitors, fuel cells and electronic devices.     

Electroactive phases of poly(vinylidene fluoride): Determination,processing and applications

Poly(vinylidene fluoride), PVDF, and its copolymers are the family of polymers with the highest dielectric constant and electroactive response, including piezoelectric, pyroelectric and ferroelectric effects. The electroactive properties are increasingly important in a wide range of applications such as in biomedicine, energy generation and storage, monitoring and control, and include the development of sensors and actuators, separator and filtration membranes and smart scaffolds, among others. For many of these applications the polymer should be in one of its electroactive phases. This review presents the developments and summarizes the main characteristics of the electroactive phases of PVDF and copolymers, indicates the different processing strategies as well as the way in which the phase content is identified and quantified. Additionally, recent advances in the development of electroactive composites allowing novel effects, such as magnetoelectric responses, and opening new applications areas are presented. Finally, some of the more interesting potential applications and processing challenges are discussed.     

Evaluation of FRP/wood adhesively bonded epoxy joints on environmental exposures

This article describes the evaluation of the durability of joints composed of wood adherends with a bonded layer of fibre-reinforced polymer (FRP) fabric. Carbon and glass fibres in an epoxy matrix were studied. The main purpose of FRP usage with timber in the construction industry is generally to improve the stiffness/strength of reinforced members without any influence on their service-life or any environmental impact. From the perspective of the timber reinforcement process, optimal dimensional stability during moisture changes in wood should be one of the most important criteria for such joints. Therefore, FRP/wood joints were evaluated with regard to the influence of real external environmental conditions on the bondline over a period of 40?months. During exposure to these conditions, specimen failures and defects were continuously visually evaluated. The decisive factor in this evaluation was bond integrity, verified by the tensile shear strength of the FRP/wood joint. After the experimental study, it was noted that the first 20?months have a significant effect on bondline failure occurrences, which involve decreases in tensile shear strength. In the next 20?months, the FRP/wood bondlines resist other severe hygrothermal stresses without significant strength decreases. An additional observed parameter was the percentage of wood failure in the bonded area of single lap joints, which characterises the mode of failure of the bonded joint. To determine the influence of ageing on adhesive due to ultraviolet radiation and varying temperature, infrared absorption spectroscopy analysis was performed to reveal changes in the macromolecular structure of the epoxy adhesive. Findings showed that UV radiation had a significant influence on the degradation of the adhesive structure.     

高分子材料在红外隐身中的应用研究

高分子材料在红外隐身材料中占有十分重要的地位。文章首先从斯特潘——玻尔兹曼定律出发,阐述了红外隐身技术的基本原理。然后按照高分子材料在红外隐身涂料中扮演角色的不同,分类介绍了红外隐身材料的国内外研究现状。最后分析了各类隐身材料的优缺点,对未来隐身材料的发展做出展望。     

高纯六氟乙烷中氯化氢的傅里叶变换红外定量分析

电子行业用作清洗和蚀刻的特种气体六氟乙烷对杂质组分HCl的含量要求严格控制在一定范围,本文建立了用傅里叶变换红外光谱仪分析其中HCl杂质的分析方法,并实现了对产品中HCl的定量分析。     

建筑用红外反射隔热涂料的研究进展

本文详述了红外反射隔热涂料的国内外研究进展,指出了该领域全色系、多功能、智能变色三个研发切入点,提出彩色及深色建筑涂料市场存在巨大缺口,并认为红外反射隔热填料与红外反射颜料、色浆等技术的结合是建筑涂料未来的发展趋势。     

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.