溶胶-凝胶模板法制备三维有序大孔TiO_2微球

采用无皂乳液聚合方法自制的单分散聚苯乙烯(PS)微球乳液为原料,并以PS微球自组装制备了有序胶体晶体模板("蛋白石"),采用溶胶-凝胶模板法制备了三维有序大孔TiO2微球("反蛋白石"),其孔呈六边形,孔径分布均一,约为200 nm,运用SEM,XRD对其形貌特征及晶型进行表征。结果表明,采用表面含有羧基的单分散聚苯乙烯微球及高的硅油粘度制得的模板有序度高;控制煅烧温度可以改变有序大孔TiO2微球的晶型,当煅烧温度为500℃时,其晶型为锐钛型,当煅烧温度为700℃时,其晶型则为金红石型。     

聚苯乙烯胶晶模板法制备三维有序大孔SiO2材料

以聚苯乙烯微球(polystyrene microsphere)自然沉积形成的胶体晶体作模板,将以正硅酸甲酯制备的SiO2溶胶填充到模板间隙中,原位形成凝胶,最后通过焙烧除去模板,得到三维有序大孔SiO2.通过SEM检测,观察到六方和四方2种有序的大孔排列方式.大孔孔径及孔径收缩率分别为240nm和19%.2种排列中,大孔之间由小窗口连通,构成三维有序大孔结构.XRD显示,制备的3DOM材料由无定形SiO2组成.     

以聚苯乙烯为模板制备有序大孔氧化铝

采用少皂乳液聚合法成功制备了单分散的聚苯乙烯微球,以微球自组装后的聚苯乙烯胶体晶体为大孔模板,铝溶胶为前驱体填充模板,干燥焙烧除去模板后制备了氧化铝载体。用激光粒度仪、扫描电镜、X射线衍射和氮气吸脱附对聚苯乙烯胶体晶体和氧化铝载体进行了表征。结果表明:少皂乳液聚合法制备的聚苯乙烯微球具有粒径较小(100~350 nm)、单分散性好(0.005)、收率高(约80%)等优点;自组装的胶体晶体呈规则有序排列,微球表面光滑洁净,并以此为模板成功制备了具有三维有序结构的、大孔孔径可调的氧化铝材料。     

有序大孔二氧化硅微球的制备研究

采用乳液聚合法合成了单分散改性聚苯乙烯（PS）乳胶粒,利用PS乳胶粒自组装制得胶体晶体（“蛋白石”）微球,通过溶胶-凝胶模板法制备了有序大孔SiO2（“反蛋白石”）微球,通过SEM对改性PS乳胶粒、胶体晶体微球和有序大孔SiO2微球表面形貌进行了表征。结果表明,改性PS乳胶粒呈单分散性,粒径为317 nm;胶体晶体微球表面PS乳胶粒排列有序;有序大孔SiO2微球表面呈有序多孔,其孔呈六边形,孔径分布均一,约为200 nm。     

利用不同造孔剂制备Al2O3多孔陶瓷

以炭黑和自制的PS微球（聚苯乙烯微球）、PMMA微球（聚甲基丙稀酸甲酯微球）为造孔剂制备氧化铝多孔陶瓷,通过SEM和其他方法对其强度、密度、外观形貌进行比较。结果表明,用PS微球与PMMA微球为造孔剂的多孔陶瓷在强度、气孔率等这些方面对多孔陶瓷的影响相近,炭黑对多孔陶瓷的各方面影响最大,以炭黑为造孔剂的多孔陶瓷比以PS微球与PMMA微球为造孔剂的多孔陶瓷的强度大、但是气孔率的稳定性差且不易控制。     

低温制备SiC多孔陶瓷及性能

采用SiC微粉为骨料,聚碳硅烷为粘结剂,混合后溶于THF中干燥过筛,经模压成型后于1000℃保护气氛下低温烧结制备SiC多孔陶瓷。运用XRD、SEM及孔隙率测定手段对陶瓷样品的物相结构、微观形貌及孔隙率进行研究,考察了不同聚碳硅烷含量对SiC多孔陶瓷抗弯强度、线收缩率及气孔率的影响。结果表明,随着聚碳硅烷含量的增加,SiC多孔陶瓷的线收缩率和失重比均增加,抗弯强度和显气孔率均先增加后下降,抗弯强度在聚碳硅烷含量为13%时达到最大值为58.45MPa,开口气孔率在PCS含量为5%时达到最大值为37.2%。     

化学气相沉积法制备新型有序大孔碳球及其表征

以二氧化硅(SiO_2)胶体微球为模板,以苯蒸气为碳源,采用胶晶模板法和化学气相沉积法,将苯蒸气在高温下碳化并沉积在SiO_2胶晶模板表面,通过氢氟酸的溶蚀作用去除SiO_2胶晶模板,制备了新型有序大孔碳球;通过场发射扫描电子显微镜、透射电子显微镜、X-射线衍射仪和物理吸附仪等对样品结构进行了表征。结果表明,当苯蒸气沉积时间为4h时,大孔碳球结构完整、排列有序,为石墨晶型。该研究为碳材料在生物医药领域的应用研究提供了新的思路和参考。     

不同生物模板低温烧结制备SiC木材陶瓷的对比研究

分别以毛竹、竹纤维、脱脂棉为模板,采用聚碳硅烷(PCS)有机溶剂浆料浸渍法,在惰性气氛下低温热解制备了SiC木材陶瓷,分别对烧成产物的微观形貌、线收缩率、体积密度、力学性能和元素组成等特征变化进行了讨论分析。结果表明:以PCS为陶瓷先驱体,选用不同生物模板,在1000℃下可低温烧结制备出SiC木材陶瓷。毛竹模板和竹纤维模板制备得到的木材陶瓷能较好地保留模板材料的原有结构,脱脂棉制模板则形成了不规则的通孔结构。随着PCS含量的增加,三种模板烧成的SiC木材陶瓷的线收缩率均逐渐降低;体积密度逐渐增大;竹纤维和脱脂棉模板制备的SiC木材陶瓷的抗弯强度逐渐增大,毛竹模板制备的SiC木材陶瓷的抗弯强度先上升后下降。相同PCS含量下,毛竹结构SiC木材陶瓷抗弯强度更大。     

有序多孔型硅热电材料的制备与性能研究

利用二氧化硅纳米微球为模板,先将Ag(银)纳米颗粒修饰在二氧化硅纳米微球表面(Ag@SiO_2微球),再将其以二维模板的形式有序排布在Si(硅片)表面,以H~+含量比较高的H_2O_2与HF作为腐蚀液,反应结束后得到孔径与分布较均匀的有序多孔硅。发现由于多孔硅的有序孔与内部空气形成声子晶体模型,加强了声子散射,使得有序多孔硅热导率相对于无序多孔硅有一定提高。     

聚碳硅烷应用的研究进展

聚碳硅烷(PCS)作为碳化硅(Si C)陶瓷的先驱体,具有陶瓷产率高、制备连续纤维可改性加工性优异以及自交联性良好等特点,被广泛用于航空航天等高科技领域。本文就聚碳硅烷的性能以及它在SiC陶瓷和其他方面的应用进行了阐述。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.