石灰石粉在复合胶凝材料中的水化性能

用扫描电镜、X射线衍射和能谱技术研究石灰石粉在复合胶凝材料中的水化性能和水化产物.结果表明:石灰石粉的掺入会降低复合胶凝材料的强度,但对后期(180 d)强度的影响会逐步减小;石灰石粉与普通硅酸盐水泥在早期(28 d)水化程度较低,后期会与铝酸盐发生水化生成水化碳铝酸钙;在铝酸钙水泥的激发下,石灰石粉早期就能参与水化生成水化碳铝酸钙.     

磨细石灰石粉对水泥浆体水化特性的影响

通过凝结时间试验、量热分析、TG-DSC分析和XRD分析研究了石灰石粉对水泥水化特性的影响.试验结果表明:石灰石粉能够促进水泥的凝结硬化,改变水泥水化历程,使诱导期缩短,加速期提前;石灰石粉导致新相水化碳铝酸钙的形成,对水泥水化产物产生影响.     

大掺量石灰石粉-水泥复合体系水化机理的研究

通过XRD、综合热分析、水化放热等测试手段对大掺量石灰石粉-水泥复合体系的水化机理进行分析,分析结果表明：石灰石粉对水泥早期水化有显著的促进作用,石灰石粉比表面积越大,效果越明显,在水化后期,部分石灰石粉参与水化反应生成少量水化碳铝酸钙,掺有石灰石粉的水化浆体中凝胶数量较纯水泥系统少。     

建筑垃圾粉活化对硫铝酸水泥基材料的影响

研究不同热活化制度下活化的建筑垃圾粉对硫铝酸水泥基材料的力学性能,凝结时间和工作性能的影响规律,并分析胶凝体系的水化放热特点及其微观产物的变化.结果表明:在不同掺量热活化的建筑垃圾粉下,硫铝酸水泥基材料的力学性能有不同程度的增强,其中600℃热活化后的建筑垃圾粉的砂浆力学性能与工作性能最优.同时,掺入热活化活化建筑垃圾粉后会使得胶凝体系的流动度下降,但能提高其力学性能,降低水化放热总量,生成水化碳铝酸钙.     

不同矿物掺合料在复合胶凝材料中水化特性的对比研究

通过强度、X射线衍射(XRD)、差热-热重(DTA-TG)及扫描电镜(SEM)测试,对比研究了玻璃粉、石灰石粉和钢渣粉在水泥基材料中的水化特性.结果表明:养护早期,钢渣粉、石灰石及玻璃粉在胶凝体系中主要作为惰性材料起到填充作用,单掺15％的石灰石粉和钢渣粉能促进胶凝体系早期强度增长.养护至90 d时,由于掺合料的二次水化作用,复合胶凝体系的强度增长率高于纯水泥样;石灰石粉能与熟料中的铝相发生水化反应生成单碳水化碳铝酸钙;钢渣粉胶凝体系内,除了水泥水化继续生成的氢氧化钙之外,钢渣粉中的活性物质如C2S和C3S后期水化也能生成氢氧化钙,使得体系内氢氧化钙含量随龄期增加而增加;玻璃粉在养护后期能与氢氧化钙发生火山灰反应,且玻璃粉火山灰反应消耗的氢氧化钙量大于水泥水化的氢氧化钙量,导致玻璃粉体系内氢氧化钙含量随龄期增加而降低.     

己二酸对掺石灰石粉水泥浆性能的影响

为探究掺加石灰石粉的水泥浆中加入己二酸的作用效果,对添加己二酸的掺石灰石粉水泥浆体流动性、强度、水化热及化学结合水的影响规律进行了研究.利用X射线衍射和扫描电镜技术手段对其机理进行分析.结果表明:己二酸的加入提高了掺石灰石粉水泥浆体的流动度、3 d强度、早期水化温升值和早期水化结合水量,掺入己二酸在3d时生成更多的水化碳铝酸钙,水化产物结构更加致密.     

石灰石粉在水泥基材料中的作用及对其耐久性的影响

作为水泥基材料的矿物掺合料,石灰石粉对它的凝结硬化、微观结构和耐久性能会有显著影响。本文概述了石灰石粉在水泥基材料中的4个作用:晶核、填充、化学和稀释作用。在一定的掺量范围内,石灰石粉的粒径越小或者掺量越大,能加速硅酸盐水泥的水化、改善孔结构和硬化水泥浆体的界面,从而提高基体性能。当石灰石粉粒径较大或者掺量过多时,石灰石粉反而起稀释作用,降低基体性能。然后基于石灰石粉的4个作用机理,综述了其对水泥基材料渗透性、碳化性能、硫酸盐腐蚀、抗冻性、钢筋锈蚀的影响。最后对掺石灰石粉水泥基材料的进一步研究工作提出了建议。     

活性与惰性掺合料对复合胶凝材料水化性能的影响

采用ESEM、MIP、XRD及SEM等测试技术研究活性(粉煤灰)和惰性(石灰石粉)掺合料对复合胶凝材料强度、孔结构及水化产物等的影响,以此揭示水泥-粉煤灰-石灰石粉胶凝材料体系的水化特性。结果表明:石灰石粉和粉煤灰复掺具有比粉煤灰更好的减水效应,复合胶凝材料的强度也比单掺粉煤灰高;石灰石粉和粉煤灰复掺时,能够很好地填充熟料颗粒间的孔隙,显著改善孔结构,降低孔隙率,使孔隙结构得到细化;石灰石粉在复合胶凝材料中后期水化明显,生成水化碳铝酸钙;SEM照片也证实了石灰石粉水化活性以及对孔结构的改善作用。石灰石粉和粉煤灰复掺能优化复合胶凝材料体系,提高材料的水化性能。     

高温条件下超高性能水泥基复合材料水化放热研究

超高性能水泥基复合材料组分复杂,高温养护会使水泥基材料水化过程发生显著变化,其早期水化、硬化及微结构形成机理仍存在众多疑惑.本文利用等温量热仪对不同水灰比、不同养护温度、不同矿物掺合料下的超高性能水泥基复合材料的水化放热过程进行研究.试验结果表明,减小水灰比、提高养护温度都将促进超高性能水泥基复合材料的水化放热进程;此外,硅灰的掺入能明显促进水化,但粉煤灰却有着延缓的作用.     

超细熟料活性效应及充填效应对石灰石硅酸盐水泥性能影响

为提高水泥熟料的有效利用率,降低水泥生产成本,改善石灰石硅酸盐水泥性能。用超细熟料、石灰石粉配制了石灰石硅酸盐水泥,在此基础上,研究了超细熟料充填效应对石灰石硅酸盐水泥堆积密实度、净浆流动性和胶砂强度的影响,以及超细熟料活性效应对胶砂强度和水化产物的影响。结果表明:超细熟料-石灰石粉复合水泥的颗粒充填堆积密实度与净浆流动性有一定的关联性,即堆积密实度越大越能改善净浆流动性;与普通细度水泥熟料对比,超细熟料具有更高的水化活性,提高了复合水泥的抗压、抗折强度,超细熟料掺量为30%时各龄期的活性效应最为理想;超细熟料的填充密实效应提高了复合水泥胶砂强度,当超细熟料掺量为30%时填充效应对强度影响最显著;与普通细度水泥熟料对比,超细熟料中的C_3A与石灰石粉中的CaCO_3反应生成了更多的水化碳铝酸钙。     

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.     

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.     

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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

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.     

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.     

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.