溶致变色法测定吡唑啉类化合物的分子二阶极化率

近年来一些具有π电子共轭的有机化合物引起了人们广泛的兴趣。这是因其中有的化合物具有较大的二阶分子极化率,因而有可能用作非线性光学材料,获得二次谐波(SHG)以及在电-光调制技术中得到应用。测定分子的二阶极化率一般的方法是通过所谓电场诱导二阶谐波测定,即EFISH法完成,但对一般的化学实验室要建该项设备并非易事,为此近年来对发展简易的测定方法受到重视。利用溶致变色法来测定上述数据是化学实验室易于完成的一种方法。其优点是理论基本健全、方法简单而且在测定中还     

双羟乙氨基-硝基型偶氮生色分子的二阶非线性极化率

设计并合成了6种具有D-π-A型和D-π-A-π-D型共轭结构的双羟乙氨基给体-硝基受体型偶氮化合物,用溶致变色法测算了分子的二阶非线性极化率。实验结果表明,双羟乙氨基和硝基是一对有效的给体、受体组合,它们与偶氮共轭链相连组成的分子具有较大的二阶非线性极化率,其中,具有D-π-A-π-D二维共轭结构的化合物,它包含两条从给体到受体的共轭链,二阶非线性极化率β1 064达到297.4×10(-30)esu,并且这个分子的透明性在6个分子中也是最好的,光学损耗最小。     

1-(芘-1-基)-3-(噻吩-3-基)丙烯酮的合成、理论计算及三阶非线性光学性质

合成一种非线性光学(NLO)有机材料查尔酮:1-(芘-1-基)-3-(噻吩-3-基)丙烯酮,通过1 H NMR、IR、HR-MS表征了其结构。采用4f相位相干成像技术测定了它的三阶NLO性质,相关参数为:脉宽4ns,激光波长为450nm,非线性吸收系数(β)=7.3×10-10 m/W,非线性折射率(n2)=-3.6×10-17 m2/W,三阶非线性极化率(χ(3))=4.12×10-11 esu;并测定了紫外光谱、荧光光谱和DSC曲线。采用密度泛函方法计算了它的轨道能量和极化率,结果表明电子转移可在分子内部进行,显示出良好的NLO活性。     

对称型双偶氮化合物的合成及其三阶非线性光学性能研究

设计并合成了一组含有二苯砜和二苯醚结构的对称型双偶氮化合物,通过红外光谱、紫外-可见吸收光谱、核磁共振和元素分析等方法对化合物材料的结构进行了表征。采用单光束Z-扫描的方法研究了它们的三阶非线性光学性能。所有化合物在稀溶液中都具有10-12(esu)数量级的三阶非线性极化系数,并且分别由非线性吸收和非线性折射两方面所贡献;分子内同时含有二苯砜吸电子基团和二甲氨基供电子基团的化合物(Azo2)的三阶非线性极化系数最大。考察化合物的分子结构对三阶非线性光学性能的影响,发现共轭型有机分子的三阶非线性光学性能是与其共轭体系的大小密切相关的。在设计这类分子结构时,关键就在于如何有效地形成大的共轭体系。     

偶氮化合物的电晕极化薄膜及其非线性光学性能研究

在有机物中,给体受体取代的偶氮化合物,由于它们具有几乎最高的二阶非线性光学效应以及作为一类新的、有前景的电光材料而倍受重视。在这方面,材料分子的非中心对称的有序排列是首先重要的。把非线性光学活性分子如偶氮化合物溶于聚合物中,再用电场极化方法得到分子有序排列的聚合物薄膜,这是目前认为最有效的材料宏观形态工程。     

印刷具有梯度折射率微结构的硫卤玻璃衍射光学元件的研究

通过一种高效而廉价的显微热极化工艺,在硫卤玻璃中刻印出覆盖可见到中红外波长且具有梯度折射率(GRIN)微结构的衍射光学元件(DOE)。研究了显微热极化的主要极化参数(极化电压U)对硫卤玻璃的微观形貌、微结构、衍射效果和梯度折射率的影响规律。在U为0.75~1.00 kV范围内发现了有效印刷GRIN微结构硫卤玻璃的形成区。表面形貌的深度、衍射级数随着U的增加而增加,但显微热极化对光学透过影响较小而不影响实际应用。显微热极化印刷后硫卤玻璃表面可以观察到周期长度为25 μm且最大相位差高达0.60λ(λ=632.8 nm)的GRIN微结构。其衍射性能的主要来源是近阳极一侧亚表面的K⁺迁移和玻璃结构重排形成周期性分布的GRIN微结构。     

三聚氰胺荧光熄灭法测定Ag(Ⅰ)的研究

基于Ag(Ⅰ)对三聚氰胺的荧光熄灭作用,建立了测定Ag(Ⅰ)的荧光分析方法.在pH为5.0的HAcNaAc缓冲体系中,测定的最大激发波长λex为256.0 nm,最大发射波长λem为363.0 nm,线性范围为2.0x10-6 ～2.4×10-2 mol/L,检出限为4.3×10-7 mol/L.将其用于废定影液中痕量Ag(Ⅰ)的测定,结果满意.     

酞菁氧钛/咔唑化合物的合成与其二阶非线性光学性能的研究

合成了具有潜在非线性光学性能的酞菁氧钛(简写为TiOPc)/咔唑化合物,用红外光谱、元素分析进行了表征,并通过实验得到了合成该化合物最佳工艺条件:n(TiOPc-SO2Cl)∶n(咔唑)=1∶1 5,反应温度150℃,反应时间为240min时,产率达到75 2%。采用溶剂化变色法估算了其二阶非线性光学性能。结果表明,其二阶非线性光学系数与基态偶极距的复合量βCTμg的值为33 9×10-30esu.D。     

二阶非线性Maker条纹测试及模拟

据Maxwell方程及电磁波在界面上的边界条件,采用Math CAD软件对1064 nm基频光在二阶非线性介质中的传播进行Maker条纹模拟,得到二阶非线性介质中产生532nm倍频光的强度模拟公式。同时对倍频晶体材料、电场/温度场极化后玻璃的实验Maker条纹测试结果与理论结果进行比较。结果表明:倍频晶体的Maker测量结果与模拟相吻合;对电场/温度场极化玻璃样品的模拟结果,在一定范围内与测量结果相一致。理论模拟可对样品制备、Maker条纹测试及二阶非线性极化机理探讨具有一定的指导意义。     

一种三齿吡啶配体的合成及光谱性质研究

以2-乙酰噻吩和对甲基苯甲醛为原料设计合成了1,5-二(2',2″-噻吩基)-3-对甲基苯基-1,5-戊二酮(化合物A)和2,6-二(2',2″-噻吩基)-4-对甲苯基-吡啶(化合物B),利用LC-MS、1H NMR确认了这两种化合物的化学结构。用紫外可见分光光度计对化合物A和B的光谱性质进行了探究,发现在300~400 nm波长范围内,化合物B相对于化合物A具有更强的光吸收性能(λ_B=329 nm,logε=4.5;λ_A=261 nm,logε=4.3)。     

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。