纳米Fe2O3的制备与气敏性质的研究

报道了纳米氧化铁的制备工艺，采用沉淀法、溶胶凝胶法制备了纳米α-Fe2O3、γ-Fe2O3粉体，用热重－差热分析（TG－DTA）、X射线衍射（XRD）、透射电镜（TEM）和二次粒度分布对粒子进行表征，并制作了气体敏感元件。讨论了纳米氧化铁的制备工艺对气敏性质的影响。     

铁(Ⅱ)无机物热解制备γ-Fe2O3及其机理

用硫酸亚铁为原料,以氢氧化钠、氨水或碳酸钠水溶液作沉淀剂,得到相应的氢氧化物或碳酸盐沉淀物作前驱体,在存在SO42-或CO32-时,500℃下进行热解,即使原料中含有少量Fe(Ⅲ),热解产物仍为纯γ-Fe2O3.用X射线衍射、透射电镜对产物进行了表征.发现其转变机理为:Fe(Ⅱ)的无机物先经空气中的氧气氧化成Fe3O4,而后进一步被氧化成γ-Fe2O3.在无SO42-或CO32-时,在相同的条件下进行热解,产物却为α-Fe2O3.     

酶诱发均匀沉淀法制备纳米Fe2O3

以硝酸铁和尿素为原料，草酸为掩蔽剂，室温下采用脲酶催化分解尿素诱发均匀沉淀，制备了纳米氧化铁前驱物。经TG-DTA，KFIR，XRD等测试表明，前驱物经热处理(500℃，2h)后，可得到α-Fe2O3纳米微粒，平均粒径44nm；SEM测试显示，Fe2O3粒子呈球形且大小很均匀，但存在团聚问题尚待解决。     

掺杂金属离子对铁的有机物热解产物的影响及其机理

系统研究了掺杂金属离子对硬脂酸铁热解产物的影响。结果显示：影响热解产物的因素不仅与掺杂离子的半径有关,而且还与其离子的电荷及电子构型有关,即掺杂离子极化力的大小决定热解产物的种类。当掺杂离子的极化力较小时,其对应的硬脂酸盐热解形成的碳酸盐能稳定存在,从而有利于生成γ-Fe2O3;反之则有利于生成α—Fe2O3。通过实验还发现：运用该观点同样可以很好地解释掺杂金属离子对其它铁的有机物热解产物的影响,提出对γ—Fe2O3起稳定作用的主要原因可能在于掺杂金属离子有机物热解形成的、处于γ—Fe2O3晶体表面的CO3^2-。     

不同晶型Fe2O3前驱物对高温变换催化剂性能的影响

针对节能型高温变换催化剂工业生产的需要,分别以α -Fe2O3,γ-Fe2O3和无定形氧化铁为前驱物制备了节能型高温变换催化剂,通过比表面积和孔径分布测定、XRD、TPR、催化活性测试等,研究了前驱物晶型对催化剂性质和CO变换反应活性的影响,以γ -Fe2O3制备的催化剂还原前后晶型变化最小,还原过程放热最少,催化活性最高,最适宜作节能型高温变换催化剂的前驱物.     

氧化铁的制备原理及脱硫活性研究

氧化铁（FexOy）在工业应用领域是重要的材料，为考察氧化铁（FexOy）的常温脱硫活性，对羟基氧化铁（FeOOH）制备氧化铁的原理进行了初步探讨，并对不同途径制备的FexOy结构特征和脱硫活性进行了研究．结果显示，采用γ-FeOOH缓慢脱水制备的纳米线状γ-Fe2O3具有很高的脱硫活性和较大的比表面积和比孔容，用其制备脱硫剂具有耐温变的特点，可用于低、中温脱硫场合．     

纳米α-Fe2O3的溶胶-凝胶法合成和表征的研究

以FeCl3.6H2O为铁源,采用溶胶-凝胶工艺制备出分散性较好、粒径均匀的纳米α-Fe2O3。系统研究了表面活性剂、pH、煅烧温度对纳米Fe2O3的晶型和粒径的影响,并借助XRD、FTIR、TEM测试手段对产物进行表征。研究发现：加入不同表面活性剂,Fe2O3粒子晶型转变的温度不同。当采用的表面活性剂为十二烷基苯磺酸钠（SDBS）,500℃煅烧前驱物时,发现制备过程中溶液的pH对产物粒子的晶型有较大的影响。     

单晶态α-Fe_2O_3纳米管的制备及其形成机理探讨

在非水溶剂正丁醇中,采用简单的有机溶剂回流加热法,在不加任何表面活性剂和分散剂的条件下,以Fe（OH）3溶胶为前驱物,通过在有机溶剂中回流加热脱水,得到了分散性良好的α-Fe2O3纳米管。对产物进行表征,XRD结果证实产物为三角晶系的α-Fe2O3,且纯度较高;TEM分析表明产物为分散性良好的单晶。进一步研究了该纳米管的形成机理,为先形成薄片状结构,再进一步卷曲为管状形貌。     

两种表面活性剂在制备纳米氧化铁过程的影响研究

以Fe Cl3和尿素为原料,分别以十二烷基磺酸钠和亚油酸钠为分散剂,采用均匀沉淀法制备纳米Fe2O3,研究了两种表面活性剂在制备纳米Fe2O3过程的影响。用XRD、FESEM对纳米氧化铁的晶体结构、晶粒度和形貌进行表征。用红外光谱仪对前驱物氢氧化铁与表面活性剂的作用进行表征。结果表明亚油酸根与Fe3+存在化学键合作用,能够有效改进制备过程中一次粒子易团聚成大颗粒的问题,制得的Fe2O3为α-Fe2O3,呈球形、晶粒度25.2nm且分散性好;十二烷基磺酸钠与Fe3+不存在化学键合作用,制得的Fe2O3晶粒度65.7nm且分散性差。     

酶诱发均匀沉淀法制备纳米Fe2O3

以硝酸铁和尿素为原料,草酸为掩蔽剂,室温下采用脲酶催化分解尿素诱发均匀沉淀,制备了纳米氧化铁前驱物.经TG-DTA,FTIR,XRD等测试表明,前驱物经热处理(500 ℃,2 h)后,可得到α-Fe     

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。