片状卤化银晶体的制备、结构与性能的研究——Ⅱ.pAg对片状颗粒的尺寸、纵横比、碘离子分布及离子电导率的影响

本文研究了双注法制备片状卤化银微晶时,pAg值对所形成的卤化银片状颗粒的尺寸、纵横此、碘离子分布以及离子电导率的影响。随着pAg值的升高,片状颗粒的尺寸和纵横比都相应地增大和升高,且越来越多的碘离子从颗粒中心向外层迁移,直至到达表层,这说明存在晶体的重结晶过程。表面层的溴碘原子比是用X射线光电子能谱仪(XPS)测定的,并测量了不同pAg值下制备的不同尺寸的片状卤化银乳剂的介电损耗频谱。其结果表明,片状颗粒的尺寸影响其离子电导率,表层碘含量的影响不明显。     

掺杂正八面体AgBr乳剂介电频谱的研究——Cd~(2+)、Br~-离子的影响

测定了单分散正八面体AgBr乳剂中加入不同量CdBr_2和KBr以后的介电吸收频谱。发现Cd~(2+)离子的表面掺杂使正八面体AgBr乳剂的介电吸收峰向低频方向位移。这种变化在CdBr_2的加入量为0—2×10~(-2)mol/mol AgBr范围内尤为明显。说明掺杂Cd~(2+)使正八面体AgBr乳剂中AgBr微晶的介电电导率σ_2显著下降。能进入AgBr微晶表面层晶格中的Cd~(2+)离子的数量不仅与乳剂中Cd~(2+)离子的浓度有关,而且与乳剂中的Br~-离子浓度有关。通过简单的水洗,可以将掺杂的Cd~(2+)大部分除去。水洗后,样品的介电吸收峰又向高频方向回移。在本实验条件下,Cd~(2+)离子掺杂的这种“可逆性”表明进入AgBr微晶中的Cd~(2+)离子主要是处在AgBr微晶的表面层内。样品介电吸收峰频率位置的这种可逆变化表明:非均匀电介质中的界面极化效应在保持连续相不变时,受分散相颗粒表面层物质的组成和结构的影响很大。     

AgBr颗粒大小的UV测量及应用研究

针对生产过程中使用激光粒度仪测量AgBr颗粒粒径分布过程中测量结果经常出现偏离测量标准的问题,对激光粒度分布仪测定AgBr颗粒粒径分布过程中,颗粒的散射过程基于Mie散射理论进行了理论计算和分析。理论分析表明产生偏离测量标准的原因主要是AgBr颗粒的复折射率和AgBr颗粒晶型的影响造成的。实验室利用双注乳化技术制备了X1、X2、X3型三种不同粒径大小的AgBr立方体颗粒乳剂,并用紫外分光光度法(UV)对乳剂颗粒进行了表征。实验表明:AgBr颗粒乳剂的特征吸收峰位与颗粒大小存在一定的线性关系,这种线性关系反映了颗粒平均粒径的大小。对X3型不同批次乳剂进行了粒径分布统计和特征吸收峰位测量,粒径分布统计表明X3型乳剂颗粒体积平均径变化范围为0.620～0.690μm,相对应的特征吸收峰峰位变化范围为383～403 nm,并用线性方程表征了两者之间的关系。提供了一种测量AgBr乳剂颗粒大小的新方法,对判断问题乳剂有重要的指导意义,对常规颗粒大小的测量方法完善提供了重要的参考价值。     

片状多层结构卤化银微晶的制备,结构和性能的研究Ⅱ

本文利用可控双注法制备了一系列碘含量相同、分布不同的片状多层结构Ag(Br,I)微晶,在前文的基础上,进一步研究了它们的不同结构与感光性能之间的关系。结果表明,当片状多层结构微晶中心有一个较大的AgBr层(例如该层所占银量超过总银量的10％)时,不管富碘层的位置何在,其敏度都不高于相同碘量但碘呈均匀分布的单层片状颗粒。对于同一类型结构,相同碘量的片状多层结构微晶乳剂,当微晶中心不存在AgBr层或中心AgBr层很小时,边缘AgBr层(或贫碘层)适当大,敏度较高。但微晶中心碘含量超过一定范围,不利于薄层、窄分布的片状颗粒的制备。     

某些稳定剂对卤化银乳剂微晶体的离子电导率的影响

利用Maxwell-Wagner效应,采用介电损耗测定法,在10kHz—3MHz的频率范围内,研究了苯亚磺酸钠(sodium benzosulfinate,简称BSI),1-苯基-5-巯基四氮唑(1-phenyl-5-mercaptotrazole,简称PMT)和5-甲基-7-羟基-1,3,4-三氮吲(口乃木)利嗪(5-methyl-7-hydroxyl-1,3,4-triazaindolizine,简称TAI)对卤化银乳剂微晶体的离子电导率的影响。加入BSI(4.76—19.07g/M AgBr)并不引起离子电导率的降低,而加入PMT和TAI(只是0.93g/M AgBr)却使离子电导率降低2个对数单位,升高了卤化银乳剂微晶体的离子电导活化能△E和表面电位eφ_s(约升高0.12eV)。进一步的研究表明:在乳剂微晶体中所含的碘,对于TAI吸附在微晶体上所引起的离子电导率的降低具有很强的抑制作用。文中对稳定剂对于离子电导性质影响的根据进行了讨论。     

中国塑料专利

有机纳米橡胶颗粒增强环氧树脂自修复微胶囊的制备方法一种有机纳米橡胶颗粒增强环氧树脂自修复微胶囊的制备方法,包括以下步骤:(1)将有机纳米橡胶颗粒分散在环氧树脂及其稀释剂的混合物中,搅拌均匀,用三辊研磨机研磨处理得到稳定分散的纳米相增强环氧树脂;(2)将乳化剂溶解在去离子     

掺杂立方AgBr乳剂介电频谱的研究——Ⅰ.Cd~( )、Cu~( )离子的影响

测定了立方AgBr乳剂经添加不同量Cd(NO_3)_2、CdCl_2、CdBr_2、Cu(NO_3)_2、CuCl_2、CuBr_2、KCl和KBr以后的介电频谱,发现Cd~( )离子只有在卤素离子存在的情况下才能进入AgBr微晶的表面层晶格,使AgBr微晶表面层内填隙银离子浓度降低,从而使AgBr乳剂的介电吸收峰明显向低频方向偏移。Cu~( )离子很难进入AgBr微晶的表面层晶格,因而对介电吸收峰的位置和形状没有明显影响。这种差别可能主要是由于Cd~( )和Cu~( )离子的离子半径、电子层构型及晶体中的配位情况不同所引起的。 最后,对Sillars方程应用于照相乳剂体系的条件作了初步探讨。     

SiO2光子晶体的垂直沉积制备与光学性能研究

采用改进的St(o)ber法合成了不同粒径的单分散SiO2微球颗粒,用种子液法制备了平均粒径约为550 nm的单分散SiO2微球颗粒,在可见光波段垂直沉积制备了SiO2光子晶体薄膜.采用紫外-可见分光光度计测试了不同反应物浓度配比所得微球制备的光子晶体薄膜的光学性能,并分析了退火对光反射性能的影响.     

单分散二氧化硅超细颗粒的制备

利用3种不同类型的表面活性剂反胶团体系制备SiO2超细颗粒,并与传统的Stober制备方法进行了对比. 在阴离子表面活性剂AOT和非离子表面活性剂TritonX-100两类体系中,得到了单分散的SiO2超细颗粒．在AOT体系中颗粒粒径随体系水含量w。的增大而增大;而TritonX-100体系中,颗粒粒径随w。的增大而减小;在阳离子表面活性剂(如CTAB,TOMAC)体系中无法得到SiO2超细颗粒．对不同体系所得颗粒的粒径标准偏差及粒度分布进行了对比,结果表明制备粒径小于100 nm的SiO2颗粒,反胶团法明显优于Stober方法,粒径相对标准偏差较低, 而对粒径大于100 nm的颗粒,Stober方法仍不失为一种很好的制备途径．     

电导法确定离子交换树脂中反离子的解离度

测定了低频下强酸离子交换树脂 001×7 和弱酸离子交换树脂 D152 的树脂床层在不同浓度电解质溶液中的电导率,利用两相分散系统的复合介电常数方程计算了树脂颗粒相的电导率,进而由树脂颗粒相的当量离子电导和无限稀释溶液中的当量离子电导求得反离子的解离度。结果表明:利用上述方法确定离子交换树脂中反离子的解离度是可行的。对于离子交换树脂床层,由于树脂颗粒外表面分散层中的反离子可沿树脂颗粒外表面切向迁移进行导电,Hanai 的复合介电常数方程需进行修正。对于弱酸离子交换树脂,也可直接通过测定等电导点的方法来确定树脂颗粒相的电导率。离子价数对反离子的解离度影响较大,离子价数越高,反离子的解离度越小。对于一价离子,H 的解离度比 K 和 Na 的解离度要低很多。     

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。