辽宁本溪变色萤石的矿物学特征和变色机理研究

变色萤石是一种在日光和白炽灯下颜色有显著差别的萤石品种，变色萤石稀有珍贵，具有极强的观赏价值。辽宁本溪是我国变色萤石的重要产地。本文以辽宁本溪变色萤石为研究对象，通过基本宝石学测试、拉曼光谱、红外光谱、电子探针、X射线荧光光谱、LA-ICP-MS测试和荧光发射光谱测试，总结了辽宁本溪变色萤石的宝石学特征、变色机理以及荧光特征。变色萤石在日光下呈现深蓝色―灰蓝色，在白炽灯下呈现紫红色。稀土元素、放射性元素的存在对于变色萤石的颜色影响很大，变色萤石在日光下呈现蓝色是Y³⁺色心、YO₂色心、胶体钙色心和2F-色心共同作用的结果。其具有变色效应与胶体钙色心和2F-色心有关。变色萤石中存在磷灰石矿物包裹体。变色萤石在长波紫外灯下发射弱蓝色荧光，但随着温度的升高荧光发射增强，这与杂质元素替代和放射性辐照产生的晶格缺陷有关。本文的结果有利于加深对于辽宁本溪变色萤石变色效应和荧光的认识。     

坦桑尼亚Umba谷电气石的变色效应

坦桑尼亚Umba谷的电气石,随光通过电气石的路径长度的增加,其颜色由绿变为红,这种颜色变化称为“Usambara”效应,与以前描述的任何颜色变化效应是不同的,采用比色法对这种电气石进行分析,分析结果表明,Usambara效应是一种复杂现象,它包括光路径长度不同而造成的变色效应和不同光源下观察到的变色效应（变石效应）。     

变色羊毛绒线的研制

本文介绍应用光谱、色谱原理研制光敏变色羊毛绒线,用特殊的染料以特定的配方染制的毛线具有变色效果,在不同光源下呈现不同的颜色。     

铬和钒在宝石变色效应中的作用

运用现代分析手段，对变石、合成变石、变色石榴石、合成及天然变色蓝宝石等多种变色宝石的化学成分及紫外-可见光光谱进行了分析，并运用晶体场理论讨论了变色效应的成因，着重分析了各种变色宝石中Cr和V在变色效应中的作用。变色效应是光源性质和宝石中致色离子的选择性吸收共同作用的结果。宝石对红、绿光的吸收达到基本平衡，才能在日光和白炽光下产生明显不同的颜色。     

热敏变色微胶囊的变色色谱拓展及其应用

为解决热敏变色材料色谱范围窄、颜色变化单一的问题,以使用原位聚合法得到的热敏变色微胶囊为基础模板,将其分别与制备的红、黄色微胶囊进行拼色实验。通过减法混色原理,不同颜色的微胶囊混合后会呈现出另一种颜色,达到了色谱拓展的目的。借助扫描电子显微镜及红外光谱仪表征了微胶囊的形貌和结构,测试了拼色样品的色差、反射率、K/S值。结果表明:成功制备出了以甲醛-三聚氰胺树脂为壁材、三芳甲烷类基础变色体系为芯材的热敏变色微胶囊;随着外界温度的变化,微胶囊混合体系的颜色也发生显著变化,实现了在不同色调之间的可逆变化,拓展了热敏变色微胶囊的变色色谱范围。     

中药茜草染色棉织物的pH值响应变色性能

为了开发pH值敏感变色纺织品,分析了不同提取剂和提取液的pH值变化对茜草提取液颜色和紫外可见吸收光谱的影响;探讨了染色pH值对织物颜色参数的影响及茜草染色织物在不同pH值环境下的变色特性。结果表明,不同提取剂对茜草色素的溶出成分不同;紫外可见光谱显示苯环的E带和K带红移;乙醇、助提剂和NaOH碱性提取液分别在400、430、510 nm呈现吸收峰。茜草提取液在pH值=3.0～11.0的条件下,呈现黄色、橙色、红色的递变;茜草在酸性和碱性条件下染色的织物分别呈黄色和红色。黄、红色谱茜草染色织物在pH值=3.0～11.0环境范围内均能呈现酸黄碱红的颜色变化,且变色可逆性良好。     

可逆热致变色油墨的色度学特性研究

本文研究了活化温度为31℃的3种含隐色染料基的热致变色油墨的色度学特性.这3种油墨具有相似的颜料粒径分布和同等厚度且对氧等离子体腐蚀相对稳定的微胶囊壳.油墨颜色与温度、引起颜色滞后的样品热史两个因素有关.比较脱色和着色过程,在CIELAB色空间中所观测的滞后环面积决定了样品上色差的大小.同一样品所能达到的最大色差是由样品不同的热史和温度决定.4个特征温度描述了引起颜色滞后的2个化学反应.当冷却到低于活化温度时,脱色状态的稳定性超过10h.热致变色效应的可逆性随着最高加热温度约呈线性降低.     

基于图像分析检测青菜叶绿素含量

为研究利用图像分析技术快速测定青菜叶绿素含量的方法,本研究将青菜分别置于不同环境进行贮藏,采用图像分析技术和分光光度计法测定了贮藏期间青菜叶颜色参数值(L*、a*、b*、ΔL*、Δa*、Δb*、(Δa*2+Δb*2)1/2、色差ΔE)和叶绿素含量,并使用不同函数模型(y=Ax+B、y=A/x+B、y=Alnx+B和ln(lny)=Alnx+B)对颜色参数和叶绿素含量进行拟合分析。结果表明:不同贮存环境下,青菜叶颜色参数ΔE与叶绿素含量之间存在稳定的线性关系,可以用函数模型y=Ax+B进行表达。利用图像分析技术建立青菜叶颜色参数ΔE与叶绿素含量之间关系定标模型相关系数为0.990 9,其定标均方根误差为0.071 7,用未参与定标的纸盒贮藏青菜叶作为预测集,其预测相关系数为0.992 8、预测均方根误差为0.010 4。     

变色丝绸的研制

变色丝绸是采用特殊染色方法染制而成的,在不同光源照射下色调变化异常显著,这不但与照射光源的光谱特性有关,而且与染物表面对照射光波的反射特性有关。文中对变色丝绸的变色原理、变色染料的选用、染色工艺及操作方法进行了较详细的论述。     

色度学基本知识(五)

五、色差和均匀标度色度图 1.色差前面我们介绍了关于颜色的定量表示方法。例如用CIE测色制的三个刺激值X、Y、Z表示,或者用色度坐标x、y和明度Y表示。这些都是属于确定某种颜色的问题。如果有     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the