玻璃纤维增强氯氧镁水泥的抗冻性及其机理

利用冻融试验方法,测定了冻融循环对普通和高性能玻璃纤维增强氯氧镁水泥(glass fiber reinforced magnesium oxychloride cement,GRMC)弯曲性能的影响,并运用XRD和SEM-EDS分析了冻融前后GRMC水化产物的组成和微观结构的差异。结果表明,普通GRMC试件冻融前后的主要物相均为5Mg(OH)2·MgCl2·8H2O(5·1·8),浸水48 h后部分5·1·8分解为Mg(OH)2;冻融循环25次后Mg(OH)2被碳化为MgCO3,在孔隙中大量存在叶片状MgCO3。双掺15%复合抗水外加剂和20%矿渣的高性能GRMC试件,在浸水48 h、冻融25次条件下物相都未发生明显变化,水泥基体仍由5·1·8凝胶体和2MgO·SiO2·aq凝胶相互连生而成,5·1·8针棒状晶体在孔隙中大量存在,冻融循环对GRMC试件的水化产物的组成和微观结构没有影响,具有较好的抗冻性。     

高性能玻璃纤维增强氯氧镁水泥的加速寿命试验与微观机理

利用SIC( strand in cement)试验方法,测定了玻璃纤维增强氯氧镁水泥(glass fiber reinforced magnesium oxychloride cement,GRMC)板材在80℃热水加速老化试验条件下的弯曲强度变化,研究了其加速试验寿命,并运用XRD、DSC -TG、FT-IR和SEM分析其水化产物组成和微观结构形貌,观察了玻璃纤维在氯氧镁水泥基体中的腐蚀特征.结果表明:未添加任何改性剂的普通GRMC在80℃热水加速老化2.5d后,其主要水化产物5·1 ·8大量分解,物相以叶片状的Mg( OH)2为主,促使玻璃纤维被基体腐蚀,导致力学性能急剧下降,预期使用寿命不超过4y.掺加复合抗水外加剂和矿渣的高性能GRMC由于5·1 ·8相的稳定存在和玻璃纤维不被腐蚀,在加速老化试验条件下的强度保留率高达60％以上,预期使用寿命超过了50 y.因此,5·1 ·8的稳定存在是保证高性能GRMC的玻璃纤维稳定性和长期耐久性的重要基础.     

矿物掺合料对高阿利特水泥混凝土性能的影响研究

本文研究了矿渣、粉煤灰和烧页岩等矿物掺合料对高阿利特水泥混凝土氯离子渗透性、力学性能及浆体孔结构的影响.试验结果表明:单掺矿渣或粉煤灰能提高抗氯离子渗透能力,复合掺加矿物掺合料可充分发挥各自的性能特性,更有效地提高耐久性能;适量单掺矿渣和烧页岩以及复合掺加矿物掺合料可以提高混凝土的强度;从机理上分析,高阿利特水泥熟料可有效激发矿物掺合料的潜在水化活性,细化了浆体孔径,从而提高了混凝土的抗氯离子渗透性能和强度.     

磷渣粉-硅灰掺合料对氯氧镁水泥微观结构和性能的影响

研究了磷渣粉-硅灰复合掺合料对氯氧镁水泥微观结构和宏观性能的影响。采用场发射扫描电镜分析了氯氧镁水泥的微观结构,并用正交试验分析了其力学性能和耐水性。结果表明,磷渣粉-硅灰复合掺合料改善了氯氧镁水泥的微观结构,水化产物排列紧凑,结构致密;磷渣粉-硅灰复合掺合料显著提高了氯氧镁水泥的强度和耐水性,硅灰对氯氧镁水泥性能的影响最大,其次是氯化镁溶液的波美度,最后是磷渣粉的掺量。     

C-S-H纳米晶核对矿物掺合料复合胶凝材料水化性能的影响研究

水泥中掺入大量矿物掺合料易造成其早期强度低、施工周期长等问题。本文研究了C-S-H晶核对含矿物掺合料的复合胶凝材料体系水化性能的影响规律;通过热力学计算阐述了C-S-H晶核降低水化产物成核势垒的机理,并通过离子溶出与沉积探讨大掺量矿物掺合料胶凝体系水化机理。结果表明:矿物掺合料复合胶凝材料体系水化能力较弱,这是由于Ca²⁺溶出受到制约,C₃S的水化反应缓慢;当加入晶核后,水泥中硅酸盐相溶解-结晶能力得到大幅提升,使得矿物掺合料水泥体系的水化反应活性接近纯水泥体系。研究表明,C-S-H晶核可解决大掺量矿物掺合料胶凝体系所带来的水化能力严重不足问题。     

含有活性或惰性掺合料的复合胶凝材料硬化浆体的微观结构特征

用压汞法测定了不同温度条件下养护的含有粉煤灰或石英粉的复合胶凝材料硬化浆体的孔隙率.用扫描电镜观察了硬化浆体的微观形貌,同时测定了各种组成的复合胶凝材料的净浆强度.常温水化初期,活性与惰性矿物掺合料都只具有物理填充的作用,硬化浆体的孔隙率和强度由矿物掺合料的掺量所决定.高温水化条件下粉煤灰的火山灰反应提前发生.随水化龄期延长,粉煤灰逐渐发生火山灰反应,使硬化浆体结构密实,其强度逐步提高.活性与惰性矿物掺合料对复合胶凝材料浆体结构与性能的影响的差异在水化后期逐渐显现.     

矿物掺合料对瓷砖胶浸水性能的影响

为提高瓷砖胶的浸水性能，本文研究了矿渣粉、偏高岭土两种矿物掺合料单掺与复掺对瓷砖胶浸水后拉伸粘接强度、吸水量及粘接层浸湿面积的影响规律，揭示了矿物掺合料在瓷砖胶中的作用机制。研究结果表明：当矿渣粉或偏高岭土单掺时，随着矿物掺合料掺量的增加，瓷砖胶浸水后的拉伸粘接强度逐渐增大，且偏高岭土对瓷砖胶浸水后的拉伸粘接强度的提升作用要优于矿渣粉。矿渣粉、偏高岭土单掺与复掺均显著提高了瓷砖胶浸水后的拉伸粘接强度，其中矿渣粉与偏高岭土以质量比1∶1（质量分数为6%）复掺时，瓷砖胶浸水后粘接强度达到最大值，为1.65 MPa。矿物掺合料单掺或复掺均可降低瓷砖胶的吸水量与粘接层浸湿面积，减缓水向瓷砖胶内部的渗透，其中复掺比单掺更有利于降低瓷砖胶的吸水量，而对粘接层浸湿面积的影响则取决于复掺时偏高岭土的掺量。物相及显微结构分析发现，掺入矿渣粉与偏高岭土后，阻碍了片状、板状羟钙石在骨料颗粒表面以及瓷砖-瓷砖胶界面的生成与结晶，形成更多C—S—H水化产物与聚合物膜复合结构层，使过渡界面的粘接结构更加密实，从而导致瓷砖胶浸水性能提高。     

复掺超细掺合料的高性能混凝土抗硫酸盐侵蚀试验研究

通常采用低水胶比、掺加高效减水剂和大掺量超细掺合料可有效改善混凝土水泥石、界面过渡区两个微结构,大大提高混凝土密实度,使混凝土强度、抗渗性、抗侵蚀性高性能化,特别是复掺超细掺合料的高性能混凝土有更佳的宏观性能。针对单掺Ⅱ级粉煤灰混凝土早期强度低的弱点,采用Ⅱ级粉煤灰和YK-Ⅲ高耐久性混凝土矿物外加剂复掺的高性能混凝土,不仅提高了各龄期强度,而且在硫酸盐侵蚀试验中,取得了优异的抗蚀效果。     

水化热抑制剂对复合胶凝材料体系早期水化动力学的影响

本文研究了水化热抑制剂(TRI)对水泥-粉煤灰-矿渣复合胶凝材料早期水化过程。通过改变矿物掺合料在胶凝材料中的质量占比以及TRI的掺量,研究了胶凝材料的水化特性,并基于Krstulovic-Dabic水化动力学模型计算了反应速率常数、几何晶体生长指数等动力学参数。结果表明,矿物掺合料和TRI复合使用会延缓胶凝材料水化并降低最大放热速率;复合胶凝材料的水化过程均有结晶成核与晶体生长、相边界反应以及扩散3个阶段,Krstulovic-Dabic水化动力学模型能较好地模拟各复合胶凝材料的水化过程;矿物掺合料和TRI会影响复合胶凝材料水化产物的结晶成核以及晶体生长,并降低复合胶凝材料各阶段的水化速率。     

矿物掺合料和减水剂对桥梁混凝土水泥石水化热的影响

采用等温量热法研究高效减水剂对普通、中热水泥掺入不同品种及不同掺量的掺合料后水化热的耦合作用规律,分析了减水剂、矿物掺合料及两者双掺对水泥水化热及放热速率的影响.结果表明:矿物掺合料可减缓水泥水化放热的速率,推迟放热峰值的出现,粉煤灰的缓凝效果和削峰效果较矿渣要显著.外加剂对掺粉煤灰水泥的早期水化热有显著的降低作用.     

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.     

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。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.