新鲜芫荽关键性香气成分的鉴定与分析

采用溶剂辅助风味蒸发法(SAFE),结合气相色谱-质谱联机(GC-MS),通过双柱对新鲜芫荽中的挥发性成分进行了鉴定,并通过谱库检索和保留指数比对,共计从新鲜芫荽中鉴定出化合物87种,其中烃类28种,醛类20种,醇类22种,酸类4种,酯类7种,酮类3种,杂环及其他类3种。通过芳香萃取物稀释分析法(AEDA),结合气相色谱-嗅闻技术(GC-O)对新鲜芫荽进行了分析,共鉴定出21种活性香气成分,其中关键性香气成分有5种[香气稀释因子(FD)≥81],分别是反-2-十二烯醛、反-2-十三烯醛、反-2-十四烯醛、3-甲硫基丙醛、反-2-癸烯醛。     

基于GC-MS和GC-O法分析两种芫荽籽精油特征性香气成分

采用气相色谱-质谱技术（GC-MS）对两种芫荽籽精油中的挥发性成分进行分析鉴定,共鉴定出42种香气化合物。通过香气强度法结合气相色谱-嗅闻技术（GC-O）对两种精油进行分析,其中12种为特征性香气成分（香气强度≥3）,分别是芳樟醇、4-松油烯醇、香叶醇、2-(4-甲基苯基）丙-2-醇、2,6-二甲基-1,7-二烯-3,6-二醇、2,6-二甲基-3,7-辛二烯-2,6-二醇、甲位蒎烯、dl-柠檬烯、乙酸香叶酯、2-莰酮（樟脑）、邻伞花烃和芳樟醇氧化物,3种关键香气成分（香气强度≥5）为芳樟醇、香叶醇和邻伞花烃。     

陈皮的挥发性香气分析

为了深入探究陈皮的挥发性香气成分,采用溶剂辅助风味蒸发法（SAFE）提取陈皮中的挥发性成分,利用气相色谱-质谱联用仪（GC-MS）和气相色谱-嗅闻联用技术（GC-O）对陈皮和九制陈皮中的挥发性风味物质进行鉴定,结果共鉴定出93挥发性成分,46种香气活性物质。为了确定关键香气物质,采用香气提取物稀释分析法（AEDA）对两种陈皮的香气活性成分作进一步分析,结果显示：萜烯类、醇类和醛类化合物是主要的香气活性物质,其中柠檬烯、月桂烯是两者共有的关键香气成分。此外,1,4-二甲基-4-乙酰基-1-环己烯、橙花醇、香茅醛、肉豆蔻醛和α-甜橙醛是陈皮中的关键香气成分;香兰素、香芹酚、紫苏醇、芳樟醇、香芹酮和β-紫罗酮是九制陈皮中关键香气成分。通过对两种陈皮的关键性风味物质进行对比分析,确定出两种陈皮中对风味贡献较大的香气化合物及其差异组分,从而为陈皮类产品的开发提供理论支撑。     

加速溶剂萃取GC-MS分析烟叶中香气成分

采用加速溶剂萃取提取烤烟烟叶中香气成分,并用气相色谱-质谱联用仪鉴定分析。采用标准谱库检索结合自动质谱退卷积定性系统鉴定,结果共鉴定出45种含量较高的香气成分,其中有18种酮、8种醇、8种醛、3种酯、2种酸、1种酚、4种其它类化合物和新植二烯等。结果显示加速溶剂萃取结合气相色谱-质谱联用仪可快速提取分析烟叶中主要香气成分。     

干草果中的关键香气成分分析

草果是一种天然香料植物,为了确定干草果中的关键香气成分,采用溶剂萃取结合溶剂辅助风味成分蒸发的方法提取了干草果果壳和干草果种仁中的挥发性成分,使用气相色谱-质谱-嗅觉检测器联用仪对所得提取物进行了分析,鉴定出22个香气活性成分;通过与标准品的香气特征、质谱、保留指数进行比对,对它们进行了定性。以2-辛醇和2-异丙基苯酚为内标,对22个香气活性成分(OACs)进行了定量分析,结果表明,OACs在干草果种仁中的含量大于在干草果果壳中的含量。计算了OACs的香气活性值;根据香气活性值,确定出了干草果中的19种关键香气成分。其中,反-2-癸烯醛、1,8-桉叶素、芳樟醇、反-2-十二烯醛、辛醛、反-2-辛烯醛、癸醛、β-蒎烯、正己醛、α-松油醇、香兰素是果壳和种仁共有的关键香气物质,它们使得二者香气具有相似之处;而(E,E)-2,4-癸二烯醛、壬醛、橙花醇、香叶醇、香叶醛、乙酸香叶酯、反式橙花叔醇、4-松油醇是导致二者香气有所不同的主要成分。     

SPME-GC-MS结合GC-O分析猪肉香精挥发性风味成分

采用固相微萃取法分别提取常压和加压制备的猪肉香精中挥发性成分,并结合气相色谱-质谱联用技术和气相色谱-嗅闻技术对萃取成分进行鉴定,结果显示：常压香精中共鉴定出46种挥发性成分,包括烃类5种（6.58%）,醛类16种（21.2%）,醇类10种（6.07%）,酯类和酸类共计9种（4.98%）,杂环及其它化合物6种（37.19%）。加压香精中共鉴定出38种挥发性成分,包括烃类3种（1.49%）,醛类14种（9.65%）,醇类6种（1.96%）,酯类、酮类和酸类共计5种（2.09%）,杂环及其它化合物10种（47.73%）。从两者中共同鉴定出的化合物有22种,包括α-蒎烯、壬醛、苯甲醛、反-2-壬烯醛、枯茗醛、反,反-2,4-癸二烯醛、蘑菇醇、4-萜烯醇、4-甲基-5-羟乙基噻唑、2-戊基呋喃、草蒿脑、茴香脑等。     

焙烤对核桃乳关键性香气成分的影响分析

以新疆核桃为原料，考察焙烤时间对核桃乳关键性香气成分的影响。通过感官分析法对核桃乳进行评价，采用溶剂辅助风味蒸发法（SAFE）提取核桃乳中的挥发性成分，并利用GC-MS和气相色谱-嗅闻-质谱联机（GC-O-MS）对核桃乳中的香气成分进行鉴定。结果表明，共从4个不同焙烤时间核桃乳中鉴定出109种挥发性化合物，主要为含氮类、醛类、醇类、杂环类和酮类等。其中，焙烤23 min核桃乳样品中，每类化合物的含量均相对较高。GC-O-MS结果显示，共从4个样品中检出69种香气化合物，同时检出化合物18种。其中，反,反-2,4-癸二烯醛、5-甲基呋喃醛、反-2-壬烯醛、2-乙基-3,6-二甲基吡嗪、2-乙基吡嗪、1-辛烯-3-醇、糠醇和4-乙烯基愈创木酚是焙烤核桃乳中的关键香气物质。综合分析结果发现，焙烤23 min核桃乳样品中，香气化合物的数量最多、香气强度较高，整体呈现典型的坚果、焙烤风味，具有较好的风味特征。     

基于GC-MS与GC-O法分析两种桔子油中特征性香气成分

采用气相色谱-质谱技术(GC-MS)分别对红桔油和绿桔油中的挥发性成分进行分析鉴定,在红桔油中鉴定出34种香气化合物,绿桔油中鉴定出26种香气化合物.通过香气强度法结合气相色谱-嗅闻技术(GC-O)对两种油中的关键香气物质(香气强度≥5)进行分析鉴定,最终确定了红桔油中的10种特征性香气成分,5种关键香气物质柠檬烯、γ...     

固相微萃取-气质联用分析锦橙果皮香气成分

为促进锦橙果皮在精细化工和食品加工中的应用,用固相微萃取-气质联用技术对锦橙果皮的香气成分进行了分析研究,通过谱库检索结合气相色谱保留指数定性方法,分离并鉴定出72个组分,已鉴定化合物占总离子流出峰面积的95.84%,主要香气成分的相对质量分数是:D-柠檬烯(68.7%)、β-月桂烯(9.92%)、芳樟醇(2.91%)、桧烯(2.15%)、香叶醛(2.14%)、橙花醛(1.46%)、α-蒎烯(1.27%)、癸醛(1.26%)。主要的香气成分是萜烯类化合物。     

木姜子干果挥发性成分的提取与分析

采用同时蒸馏萃取法(SDE法)对木姜子干果中的挥发性成分进行提取,并用气相色谱-质谱联用仪对成分进行分析鉴定,以峰面积归一化法对各成分进行定量。得到鉴定的挥发性成分共77种,其中相对质量分数较高的成分包括d-苧烯(14.51%)、香叶醛(9.81%)、橙花醛(8.47%)、芳樟醇(7.03%)、甲基庚烯酮(4.15%)、α-松油醇(3.22%)、香叶醇(3.07%)、β-石竹烯(2.58%)、氧化石竹烯(2.56%)、α-蒎烯(2.46%)。简要阐述了各香气成分对木姜子干果香气特征的贡献情况。     

Effects of calcination condition on expansion property of MgO-type expansive agent used in cement-based materials

Previous research indicated that the expansion property of MgO-type expansive agent (MEA) depended strongly on the calcining conditions, i.e. kiln temperature and residence time. However, the intrinsic effect of calcination condition on the expansion property of MEA has not been clearly demonstrated. In the present work, the effects of calcination condition on the microstructure, hydration activity, and expansion property of MEA have been investigated, and their correlations are also studied. Results indicate that the microstructure of MEA is the intrinsic factor that controlling its expansion property, which is influenced by the calcination condition. MEA produced under higher temperature and longer residence time has less interior pores, larger crystal size of MgO, and smaller specific surface area, thus resulting in lower hydration activity and slower expansion at early age, but larger “ultimate” expansion at late age. While, a new expansion model of MEA is proposed to explain these results.     

Material and environmental parameter effects on the leaching of cement pastes: Experiments and modelling

Results already published on the leaching of cement pastes have shown that the kinetics depends sensitively on the material and environment. However and because of the variability of the tested materials and leaching protocols, it is difficult to compare these data and quantify the effect of each parameter. In this paper, a large experimental database on the leaching kinetics of cement pastes is built. Four parameters are investigated: type of cement (portland cement, silica fume cement, slag cement, ternary cement with slag and fly ash); water-to-cement ratio (0.5; 0.4; 0.25), temperature (26 °C; 72 °C; 85 °C) and chemical composition of the leaching solution (pure water, mineralised water, ammonium nitrate solution). Firstly, the database is used to calculate the leaching kinetics of the cementitious materials. Secondly, a simplified model predicting the one-dimensional leaching kinetics for other water-to-cement ratios and temperature up to 85 °C is presented.     

Toughening of polypropylene with styrene/ethylene‐butylene/styrene triblock copolymer: Effects of reactive and nonreactive compatibilization

The effects of the compatibilization on the toughening of polypropylene (PP) by melt blending with styrene/ethylene‐butylene/styrene triblock copolymer (SEBS) in a twin‐screw extruder were investigated. The compatibilizers used were an SEBS functionalized with maleic anhydride, a PP functionalized with acrylic acid, and a bifunctional compound, p‐phenylenediamine (PPD). The effects of the compatibilization were evaluated through the mechanical properties and by the determination of the phase morphology of the blends by scanning electron microscopy. Reactive compatibilized blends show up to a 30‐fold increase in impact strength compared to neat PP, which was likely to have been due to the reaction of the bifunctional compound (PPD) with the acid acrylic and maleic anhydride groups, which rendered both morphological and mechanical stability to these blends. The addition of the PPD to the blends significantly changed their phase morphologies, leading to larger dispersed particles' average diameters, probably due to the morphological stabilization at the initial processing steps during extrusion, with the occurrence of the chemical reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1081–1094, 2003     

Photocatalytic degradation of air pollutants — From modeling to large scale application

Indoor as well as outdoor air quality and their limiting values remain a major problem to our present-day society.This paper addresses the modeling of the decomposition process of nitrogen monoxide (NO) on reactive concrete surfaces under the controlled exposition of a UV source. Within this model the external mass transfer of the pollutant and the internal molecule diffusion-reaction were considered. A first-order kinetics equation is derived with respect to the NO concentration and a site-competitive adsorption between NO/NO₂ and water molecules, resulting in a dependence of the reaction kinetics on the relative humidity. Using the proposed model, a reaction rate constant k and an adsorption equilibrium constant K_d can be derived which describe an active paving stone accurately. Experimental results from a self-developed photoreactor with continuous flow mode were used to validate the proposed kinetic expression. Furthermore, the effect of variations in process conditions such as irradiance and relative humidity on the two constants k and K_d is investigated. All modeling work provides a sound foundation for the translation of this process to real outside conditions. In this regard an upcoming project in a Dutch city is described in brief.     

(SrZrO_3)_(10)(SrTiO_3)_(90)缓冲层对PZT结晶及性能的影响

采用Sol-gel法制备了PbZr0.52Ti0.48O3 (PZT)薄膜,并研究了(SrZrO3)10(SrTiO3)90((SZO)10(STO)90)缓冲层对PZT薄膜结晶和性能的影响.X射线衍射(XRD)结果表明:(SZO)10(STO)90缓冲层对PZT薄膜结晶有取向诱导作用,由(SZO)10(STO)90诱导的PZT薄膜有很强的(111)择优取向,缓冲层将PZT薄膜的取向度α由45.0%提高到了90.1%以上;PZT的(111)择优取向提高了薄膜的电性能,使剩余极化强度Pr从26.8 μC/cm2增大到38.8 μC/cm2.     

硫氰酸锰及其相关衍生物的合成及化学表征

合成了金属有机配合物非线性光学晶体硫氰酸汞锰，及其相关衍生物，二二甲亚砜合硫氰酸汞锰，乙二醇一甲醚合硫氰酸汞锰，二水合二N，N－二甲基乙酰胺合硫氰酸汞锰，二水合二N－甲基－α－吡咯烷酮合硫氰酸汞锰。采用元素分析，红外光谱以及紫外－可见－近红外透央求我谱分析对其进行了化学表征。     

Design and processing of ZnO doped tricalcium phosphate based materials: Influence of β/α polymorph phase assemblage on microstructural evolution

Tricalcium phosphate (TCP) based biomaterials are excellent candidates in hard tissue engineering due to their similarity to the natural bone composition and outstanding properties. The presence of additives such as (Mg²⁺, Zn ²⁺, F⁻, CO₃²⁻ and/or SiO₄⁻) in solid solution in the structure of TCP, affects the stability of its different polymorphs and therefore the properties of TCP based biomaterials. It is known that the incorporation of zinc in TCP in the non-toxic level stimulates bone growth and its mineralization, hence its interest. Nevertheless its effect on phase assemblage and microstructure evolution has not been clearly established. The main purpose of this study was to synthesize TCP and zinc doped monophasic/biphasic α/β-TCP dense biomaterials, by solid-state sintering process, with different ZnO contents and controlled phase proportions and microstructure on the final material. The effect of ZnO content and sintering temperature on phase assemblage, densification and microstructural evolution has been investigated.     

Optimizing multiple qualities in as‐spun polypropylene yarn by neural networks and genetic algorithms

This investigation considers a quantitative procedure for determining the values of critical process parameters in melt spinning to optimize the qualities of denier, tenacity, breaking elongation, and denier variance in as‐spun polypropylene yarn. An orthogonal array in the Taguchi method defines the minimum set of parameter‐level combinations that are experimentally tested. The significant process parameters, namely the third extruder barrel temperature, spinning temperature, metering pump speed, and take‐up velocity, are identified on the basis of the analysis of variance and F test. After a confirmation experiment is conducted to ensure the reproducibility of the experimental results, the back‐propagation neural network establishes a continuous system linking 10 process parameters and four qualities. The technique for order preference by similarity to an ideal solution can be used to obtain a performance measure for assessing multiple qualities. The genetic algorithm attempts to find parameter values for optimizing the quality performance, including the denier, tenacity, breaking elongation, and denier variance. Finally, the experimental results demonstrate that the smallest denier, largest tenacity, smallest breaking elongation, and second smallest denier variance of as‐spun polypropylene yarn can be achieved with the proposed approach in melt spinning. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2532–2541, 2006     

Selective plasma‐induced grafting of polystyrene onto polyolefin blends

Plasma pretreatment has been used to generate reactive radicals and oxygenated groups on polymer surfaces for graft polymerization. The polymer substrates studied were composed of a polypropylene–polyethylene (PP–PE) copolymer, which was predominantly PP, and also contained blended ethylene–propylene rubber (EPR) as either about 15 or about 60 mol %. A pure PP substrate was also studied for comparison. The grafted polymer was polystyrene (PS). Raman microspectroscopic 2‐dimensional mapping was used to elucidate the role of crystallinity and EPR in the plasma treatment and graft polymerization process. It was found that the plasma pretreatment favored the EPR component of the substrate and the graft yield was related to the EPR content. Crystallinity seemed to have a much less significant effect on the grafting reaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1643–1652, 2003     

Porosity and specific surface area of Roman cement pastes

Mercury porosimetry, water vapour and nitrogen adsorption were used to follow the hydration of Roman cements — belite cements calcined at low temperature. Generally, unimodal distribution of pore sizes was observed, with the threshold pore width decreasing considerably with increasing curing time. An open porous structure with the threshold pore diameter between 0.2 and 0.8 μm and the specific surface area not exceeding 20 m²/g was produced at early ages when quick growth of the C–A–H phases is observed. The surface area reached up to 120 m²/g and the threshold pore width shifted to around 0.02 μm when the subsequent formation of C–S–H gel filled the larger pores. Both mercury porosimetry and water vapour adsorption were found to be capable of following the progress of hydration of the Roman cements with high reliability at least for a comparative evaluation of historic Roman cement mortars and repair materials used in restoration projects.