近红外光谱在测定汽油重要指标中的应用

介绍了近红外光谱在汽油生产控制分析中的应用。在标准方法测定数据的基础上,采用偏最小二乘法建立了适合催化汽油和成品汽油测定RON、芳烃、烯烃的分析模型,并用大量试样对所建分析模型的可靠性进行了考察。结果表明,近红外光谱的测定结果与标准方法的测定结果有很好的一致性。近红外光谱技术的应用可以提高分析效率,降低分析成本,对装置的平稳运行和成品汽油的优化调和起到积极作用。     

近红外光谱法在快速测定汽油性质中的应用

在标准方法测定数据的基础上,运用化学计量学方法,建立了非成品汽油的辛烷值、芳烃、烯烃含量的近红外光谱校正模型,并用常规分析方法验证了模型的准确性和重复性。实验表明,近红外光谱法能在3～5min内快速、准确地一次测定非成品汽油的辛烷值、芳烃、烯烃含量。     

分数阶微分在红外光谱数据预处理中的应用

比较了Grumwald-Letnikov分数阶微分算法和常用的Savitzky-Golay算法对汽油样品近红外光谱数据1阶微分和2阶微分结果。对25个汽油样品和41个煤炭样品的近红外光谱数据通过Savitzky-Golay算法进行平滑,平滑后1阶微分和平滑后2阶微分处理;通过Grumwald-Letnikov算法进行平滑后的0.2～2.2阶的21个阶次的微分处理。汽油样品的处理数据结合汽油的辛烷值、初馏点指标数据和煤炭样品的处理数据结合煤炭挥发分、氢含量和氮含量指标数据分别通过PLS建立数据模型,利用留一法全交互验证选取最优主成分。通过预测残差平方和(PRESS)和相关系数(R)对数据,处理方法进行评估。结果表明:分数阶微分可以应用于近红外光谱的数据预处理,对于相同数据的不同指标取得最优值的分数阶微分的阶次是不同的。     

基于近红外光谱的茶叶中粗纤维快速测定方法研究

近红外光谱技术由于其操作简单、无需前处理、不破坏样品、无需化学试剂等特点受到人们的青睐,在众多领域得到研究和应用。本文就利用近红外光谱技术快速检测茶叶中粗纤维含量的方法进行研究,首先确定了茶叶样品粉碎时的最佳颗粒度和采集样品近红外光谱时的最佳装样厚度,选用135个茶叶样品作为试验对象,结合国标方法(GB/T 8310-2013)测定样品的粗纤维含量值,利用偏最小二乘方法建立了茶叶中粗纤维含量快速测定的近红外模型,并对60个未参加建模的茶叶样品进行了预测,将模型预测结果与国标方法结果进行成对结果 t检验,统计分析结果证明近红外方法与国标方法不存在显著差异,证明了近红外光谱法在茶叶中粗纤维快速检测中应用的可行性。     

近红外光谱技术在中药栀子渗漉液理化指标快速分析中的应用研究

用声光可调滤光器(AOTF)-近红外(NIR)光谱法在线分析栀子渗漉液密度及栀子苷含量。在线收集栀子渗漉液样品,建立栀子渗漉液的含量、比重数据库,同时采集近红外光谱图谱,用偏最小二乘(PLS1)法分别建立NIR光谱与含量、比重数据之间的校正模型,并对在线过程中收集的预测集样品进行含量预测来验证所建模型。结果表明,渗漉液NIR光谱与含量、比重数据之间的校正模型相关系数R2分别为0.956 0和0.978 2,外部样品预测平均相对偏差分别为0.09%,2.84%;该方法精密度RSD分别为0.06%,2.96%;稳定性RSD分别为0.63%,1.89%;预测回收率分别为100.0%,99.9%。近红外光谱技术在栀子渗漉液密度及淫羊藿苷含量分析中具有快速、直接、多成分同时测定,并能实现现场分析。     

近红外漫反射分析技术在测定共聚聚丙烯中乙烯含量的应用

文章探讨了利用近红外漫反射分析技术快速判断共聚聚丙烯中的乙烯含量的应用。用近红外漫反射法收集了样品近红外光谱图。利用中红外方法测定共聚聚丙烯样品的乙烯含量。利用偏最小二乘法线性回归法建立了聚丙烯中聚乙烯含量的近红外光谱预测模型。将近红外法测定结果与中红外方法测定结果进行了比较,对光谱测量的重复性进行了考察。结果表明,利用近红外光谱法与中红外方法的测定结果无显著差异,近红外法具有准确,快速,操作简便和低成本等特点。     

基于中红外光谱的汽油组成快速分析方法

研究了中红外光谱用于车用汽油组成快速分析的方法,建立了多种汽油标号通用的苯、芳烃、烯烃和MTBE含量的校正模型,相关系数分别为0.9939、0.9942、0.9793、0.9987,对车用汽油中苯、芳烃、烯烃和MTBE含量的预测标准偏差为0.0179、0.354、0.695、0.0345,实验证明中红外光谱测定值和色谱法测定值之间具有较好的相关性,该方法能为生产和储运销环节的质量控制快速提供分析数据。     

近红外光谱技术在油品检测中的应用

油品在检测过程中,常需要对其如汽油辛烷值、汽油烃类含量、柴油十六烷值等指标进行检测,如果都在实验室进行专业分析的话,费用高且时效性不强。而近红外光谱技术就可以解决这一点,此方法可以对油品的部分项目进行实时检测,是一种快速、廉价、对样品没有损耗的方法。本文通过近红外光谱技术对汽油中烃类物质的分析检测,展示近红外光谱技术在油品分析中的具体应用。     

制浆材综纤维素和聚戊糖含量的近红外预测

用传统方法测定了156个制浆材样品的综纤维素和聚戊糖含量并采集了样品的近红外光谱。对原始光谱进行多元散射校正后,运用偏最小二乘法和交互验证的方法,确定最佳主成分数分别为9和10并建立样品综纤维素和聚戊糖含量的校正模型。独立验证中两个模型的决定系数R_(val)~2分别为0.903 4、0.940 1,预测均方根误差(RMSEP)分别为0.69%、0.78%,相对分析误差(RPD)值分别为3.22、4.09,绝对偏差(AD)分别为-1.00%~1.20%、-1.39%~1.31%,两个校正模型较好地预测了验证集样品的综纤维素和聚戊糖含量,基本满足制浆造纸工业中快速测定的需求。     

近红外光谱法快速测定高含量精制甘油中的甘油含量

采用偏最小二乘法(PLS)建立了快速测定高含量精制甘油中甘油含量的近红外光谱校正模型,该模型主因子数为4,相关系数(R2)为99.12%,校正标准偏差(RMSECV)为0.027;以预测集对模型进行验证,结果表明,R2为99.17%,预测标准偏差(RMSEP)为0.023,对同一样品预测值的相对标准偏差(RSD)为0.04%。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。