降温速率对磷酸二氢铵介稳区影响的研究

采用聚焦光束反射测量（FBRM）技术测定了磷酸二氢铵溶液介稳区宽度。测定了不同降温速率下磷酸二氢铵溶液的成核温度,得到对应的磷酸二氢铵结晶介稳区宽度。结果表明：在降温速率一定时,磷酸二氢铵溶液过冷度随温度降低而增加,介稳区变宽;在不同降温速率下,介稳区宽度随降温速率增加而增加,其中降温速率为 1.0 ℃/min时介稳区宽度最大,降温速率为0.2 ℃/min和0.1 ℃/min时介稳区宽度不变。     

磷酸二氢铵结晶介稳区的研究

研究了不同温度、不同降温速率及不同搅拌速度下磷酸二氢铵（MAP）水溶液介稳区宽度,同时研究了杂质离子Mg^2＋,Fe^3＋,Al^3＋对MAP水溶液介稳区宽度的影响。介稳区宽度随温度升高和搅拌速度增大而变窄;随降温速率增大而变宽,且溶液结晶成核级数与饱和温度无关。Mg^2＋,Fe^3＋,Al^3＋等杂质离子的存在均使介稳区宽度变宽,Fe^3＋和Al^3＋对介稳区的影响都很大,Mg^2＋对其影响较小。在饱和温度为50℃、杂质质量分数为0.005%时,Fe^3＋使介稳区变宽2.3℃,Al^3＋使介稳区变宽1.1℃;Al^3＋质量分数为0.1%时,使介稳区变宽9.3℃。并得到介稳区宽度与铝离子质量分数的定量关系,为MAP工业结晶过程的控制提供理论依据。     

L-酒石酸水溶液结晶介稳区和诱导期的测定

在20~60℃温度范围内,采用激光法测定L-酒石酸在水中的结晶介稳区宽度和诱导期,分别研究了饱和温度、冷却速率和搅拌速率对L-酒石酸结晶介稳区宽度的影响以及过饱和度对L-酒石酸诱导期的影响。结果表明:结晶介稳区宽度随着饱和温度、搅拌速率的增大和冷却速率的降低而变窄,并推算出表观成核级数m,给出了成核速率方程,此外实验测定结晶诱导期随过饱和度S增大而变短,基于经典成核理论和诱导期数据,计算出L-酒石酸在水中20℃和25℃下的固液界面张力。     

L-酒石酸水溶液结晶介稳区和诱导期的测定

在20~60℃温度范围内,采用激光法测定L-酒石酸在水中的结晶介稳区宽度和诱导期,分别研究了饱和温度、冷却速率和搅拌速率对L-酒石酸结晶介稳区宽度的影响以及过饱和度对L-酒石酸诱导期的影响。结果表明:结晶介稳区宽度随着饱和温度、搅拌速率的增大和冷却速率的降低而变窄,并推算出表观成核级数m,给出了成核速率方程,此外实验测定结晶诱导期随过饱和度S增大而变短,基于经典成核理论和诱导期数据,计算出L-酒石酸在水中20℃和25℃下的固液界面张力。     

DMT甲醇溶液结晶介稳区性质的研究

研究了对苯二甲酸二甲酯（ＤＭＴ）甲醇溶液的结晶特性。测定了ＤＭＴ在甲醇中的溶解度、ＤＭＴ甲醇溶液于不同降温速率、搅拌转速下的结晶介稳区宽度以及不同过饱和度下的结晶成核诱导期。结果表明：ＤＭＴ在甲醇溶液中的溶解度随温度升高而增加;溶液的结晶介稳区随降温速率的增加变宽,随搅拌转速的增加而变窄,且ＤＭＴ甲醇溶液的结晶诱导期随相对过饱和度的增加而缩短。     

铵明矾在氯化钠溶液中结晶介稳区和诱导期的测定

在293. 15～323. 15 K温度范围内,采用激光法测定了铵明矾在氯化钠溶液中的介稳区宽度和诱导期,分别研究了不同饱和温度、搅拌速率和降温速率对铵明矾介稳区的影响以及各温度下过饱和度对铵明矾诱导期的影响。结果显示,铵明矾在氯化钠溶液中的结晶介稳区均随着搅拌速率和饱和温度的增大而变窄,随着降温速率的升高而变宽;根据Sangwal的3D成核理论方程推算出铵明矾在氯化钠溶液中的成核活化能;此外实验测定铵明矾的诱导期随着过饱和度和饱和温度的增大而缩短,根据诱导期实验数据和经典成核理论,计算出293. 15～303. 15 K温度范围内铵明矾在氯化钠溶液中的界面张力。     

降温速率对过硫酸铵结晶介稳区影响的研究

用电阻法测定过硫酸铵溶液的结晶介稳区宽度;采用不同的降温速率进行了过硫酸铵结晶热力学数据的测定,得到了过硫酸铵各个降温速率下的过饱和浓度曲线,从而得到了过硫酸铵结晶的介稳区宽度。结果表明:在相同的降温速率下,过硫酸铵的过饱和浓度随温度的升高而增大,在温度为40~50℃的范围内,过硫酸铵介稳区宽度明显增大;在不同的降温速率下,介稳区宽度总体最大的是降温速率为40℃/h。这为过硫酸铵工业结晶的生产提供了理论依据。     

硫酸铵介稳区宽度的研究及成核动力学计算

介稳区宽度(MSZW)是无机盐工业结晶过程设计的重要参数,在工业生产硫酸铵过程中,可将结晶条件控制在介稳区以制备高纯度大颗粒硫酸铵。采用多温法测定了313.15~343.15 K温度范围硫酸铵的介稳区宽度。研究了显著影响硫酸铵介稳区宽度的因素,如冷却速率、初始组成、搅拌速率、溶液体积及晶种。实验结果表明,硫酸铵介稳区宽度随初始组成、搅拌速率、晶种质量的增加而降低;随冷却速率的提高而变宽;溶液体积则对介稳区宽度没有影响。以溶解度数据为基础,通过范特霍夫方程计算了硫酸铵的溶解焓。采用自洽N伥vlt型方程及3D成核理论,由实验介稳区宽度数据估算硫酸铵成核动力学,得到了临界成核参数,包括成核级数m、成核常数K和固-液界面能γ。     

磷酸二氢钠结晶介稳区宽度的研究

溶液的介稳区宽度是结晶过程的基础研究之一。实验测定了纯磷酸二氢钠溶液在不同饱和温度下的介稳区宽度及25℃时含有杂质的磷酸二氢钠溶液的介稳区宽度,同时考察了pH值和降温速率对溶液介稳区宽度的影响。介稳区宽度的测定结果对指导磷酸二氢钠的结晶过程有参考价值。     

绿原酸结晶介稳区宽度的测定

采用激光装置测定不同条件下绿原酸在乙醇和水中的溶解度及超溶解度,并比较了不同温度、降温速率和搅拌速率下绿原酸的介稳区宽度。结果表明介稳区宽度随温度降低,降温速率升高及搅拌速率减小而变宽,乙醇和水体系中进行结晶的最优条件均为降温速率12℃·h~(-1)和搅拌速率300 r·min~(-1),其介稳区宽度分别介于3.7~6.3℃和3.7~8.0℃。     

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。