固化模拟放射性核素Sr对磷酸镁水泥水化特性的影响EI北大核心CSCD

研究了固化模拟放射性核素Sr对磷酸镁水泥性能的影响,通过分析固化体水化热、物相组成及微观形貌,探讨了Sr对磷酸镁水泥水化特性的影响机理。结果表明:固化体的力学性能优异,1 d抗压强度即可达到国家标准的4.5倍以上;磷酸镁水泥固化体具有优异的抗浸出性,42 d浸出率及累计浸出分数远低于国家标准的要求;Sr会阻碍磷酸盐在水化初期的水解及电离,同时MgO溶解及水化产物MgKPO_4·6H_2O生成的速率随Sr掺量增大而减缓;掺入Sr后水化产物生成量大幅下降是水化初期抗压强度降低的主要原因,随着龄期增长,水化产物结晶程度降低、结构改变以及孔隙孔径增大成为固化体抗压强度降低的主要原因。     

固化模拟放射性核素Sr对磷酸镁水泥水化特性的影响

研究了固化模拟放射性核素Sr对磷酸镁水泥性能的影响,通过分析固化体水化热、物相组成及微观形貌,探讨了Sr对磷酸镁水泥水化特性的影响机理。结果表明:固化体的力学性能优异,1 d抗压强度即可达到国家标准的4.5倍以上;磷酸镁水泥固化体具有优异的抗浸出性,42 d浸出率及累计浸出分数远低于国家标准的要求;Sr会阻碍磷酸盐在水化初期的水解及电离,同时MgO溶解及水化产物MgKPO_4·6H_2O生成的速率随Sr掺量增大而减缓;掺入Sr后水化产物生成量大幅下降是水化初期抗压强度降低的主要原因,随着龄期增长,水化产物结晶程度降低、结构改变以及孔隙孔径增大成为固化体抗压强度降低的主要原因。     

新型磷酸镁水泥固化挥发型重金属锌的研究

利用新型磷酸镁水泥对挥发型重金属锌做固化研究。通过测定磷酸镁水泥的抗压强度、Zn ²⁺的浸出毒性、水化产物的组成,观察固化后水泥表面微观结构,分析了锌在磷酸镁水泥中的赋存状态及化学态,以此来探究新型磷酸镁水泥对重金属锌的固化效果及机理。结果表明：Zn ²⁺的掺量由0增至4%（质量分数,下同）时,56 d龄期的抗压强度降低了21.9%。当Zn ²⁺掺量为4%时,1 d龄期的浸出质量浓度达最大值6.6 mg/L。Zn ²⁺抑制磷酸镁水泥的水化过程,磷酸镁水泥对锌的固化作用包括物理包覆和化学结合。锌主要以Zn₂（PO₄）（OH）沉淀物质形态被固化在水泥中,Zn ²⁺经磷酸镁水泥固化后+2价态并未改变。     

沸石改性磷酸镁水泥固化模拟放射性核素133Cs

利用沸石改性磷酸镁水泥,对模拟放射性核素133Cs进行固化,研究了固化体的抗压强度、抗冲击性、抗浸泡性、抗冻融性和抗浸出性,并分析了固化体的物相组成、孔结构和微观形貌.试验结果表明,沸石改性磷酸镁水泥含Cs固化体具有较好的力学性能;掺入沸石改善了固化体的抗冻融性、抗浸泡性和抗浸出性,掺入10％沸石使Cs+的42 d累积浸出分数下降了42.2％,沸石一方面增强了固化体的密实程度,提高了固化体的机械固化能力,另一方面沸石的晶体结构增强了固化体对Cs+的吸附固化能力.     

粉煤灰对硫氧镁水泥抗压强度的影响

为了研究粉煤灰对硫氧镁水泥抗压强度的影响,对不同H2O/MgSO4摩尔比的硫氧镁水泥掺入粉煤灰后的硬化体的抗压强度进行了测试,讨论了粉煤灰对硫氧镁水泥抗压强度和水化产物的影响.结果表明,在龄期1d时,各配比硫氧镁水泥抗压强度均随粉煤灰掺量的增加(0％～50％)而降低,在28 d龄期时,对于H2O/MgSO4的摩尔比为20时,硫氧镁水泥抗压强度随粉煤灰掺量增加而增加,对于H2O/MgSO4的摩尔比为28时,硫氧镁水泥抗压强度随粉煤灰掺量增加而呈降低趋势.粉煤灰颗粒的填充孔隙作用使得硫氧镁水泥硬化体更加密实,可提高硫氧镁水泥抗压强度.     

硼砂对磷酸镁水泥抗压强度的影响研究

研究了磷酸二氢钾与重烧氧化镁的质量比(P/M)、水胶比对磷酸镁水泥(MPC)硬化性能的影响,并探讨了硼砂对磷酸镁水泥性能的影响.测试了磷酸镁水泥的抗压强度,并利用XRD和SEM分析了磷酸镁水泥的水化产物的物相组成和微观形貌.结果表明,磷酸镁水泥的抗压强度随P/M质量比的增加先增大后减小,当P/M=1∶3时达到最大值,此时产生的水化产物为结晶度很好的板状晶体;随着水胶比的增大,磷酸镁水泥的抗压强度先增大后减小,当其在0.12～0.14时达到最大值;随着硼砂掺量的增加,磷酸镁水泥各龄期的抗压强度先增大后减小,且随着龄期的增长抗压强度逐渐增大;加入硼砂后,磷酸镁水泥晶体呈现出裂纹和缺陷.     

磷酸钾镁水泥基材料与硅酸盐水泥混凝土的粘结性能研究

为了研究磷酸钾镁水泥基材料与硅酸盐水泥混凝土的粘结性能,测试了磷酸钾镁水泥基材料浆体的抗压强度,同时测试了磷酸钾镁水泥基材料浆体与不同状态的硅酸盐水泥砂浆的粘结抗折强度和收缩变形,分析了磷酸钾镁水泥基材料硬化体的物相组成、微观形貌以及与硅酸盐水泥砂浆基体的粘结界面结构.结果表明:双掺粉煤灰和石灰石粉,使磷酸钾镁水泥基材料硬化体的结构更完善,抗压强度、粘结抗折强度和体积稳定性均明显提高.保持硅酸盐水泥砂浆基体的龄期大于7d和气干含水状态,磷酸钾镁水泥基材料与硅酸盐水泥砂浆界面的结合力加强,粘结抗折强度明显提高.     

原材料及配比对磷酸镁水泥强度的影响

研究了M/P比值(Mg O与K2HPO4的质量比),水胶比(W/C),硼砂掺量,Mg O比表面积对磷酸镁水泥早期强度的影响,采用扫描电子显微镜对磷酸镁水泥的微观形貌进行了表征。结果表明:磷酸镁水泥1 h的抗压强度随M/P比值的增大而减小,在水化龄期为3 d和7 d时,M/P比值为4:1时磷酸镁水泥石的强度最高,最高强度达到了74.68 MPa,水胶比对磷酸镁水泥石早期强度影响不大,7 d强度随着水胶比的增大而减小,磷酸镁水泥在水化早期随着硼砂掺量的增加,水化产物晶体变得细小,晶体缺陷增多,结构疏松,其强度随着硼砂掺量增加而降低,后期水化产物连接成一体,结构致密,7 d的强度几乎没有变化。水化龄期在7 d内,磷酸镁水泥石的强度随Mg O比表面积的增大而增大。     

偏硅酸钠掺量对高硼废液水泥固化体力学性能的影响

为研究偏硅酸钠掺量对高硼废液水泥固化体力学性能的影响,测试了3％、5％、7％(质量分数)碱当量下水泥固化体的抗压强度,采用量热实验、XRD、FT-IR、TG-DSC、SEM等分析技术,对水化产物建立起宏观性能和微观结构的联系,探究力学性能变化的微观机理.实验结果表明:对于普硅水泥-高硼溶液体系,以偏硅酸钠为激发剂,相同龄期下,随着碱当量的增加,试样的抗压强度随之增加;碱当量为5％以上时,试样的各龄期抗压强度可显著提高,28 d抗压强度达10.36 MPa以上.碱当量的增加使得水化产物中的氢氧化钙增多,从而填充了水泥固化体中的空隙,使其强度提高;产物中的C-S-H凝胶是固化体抗压强度的主要来源.     

利用磷酸镁水泥固化富集型重金属铜和镍研究

利用磷酸镁水泥对富集型重金属铜和镍进行固化研究。对掺入硝酸铜和硝酸镍水泥的抗压强度、铜镍离子浸出质量浓度、水化产物组成等进行测定,观测水泥表面的微观形貌,分析铜镍离子在水泥中的化学态及赋存状态。研究表明：硝酸铜掺量为0~3%（质量分数）时,水泥的抗压强度随着铜离子掺量的增加呈现先增大后减小的趋势,当硝酸铜掺量为1%时,水泥7 d抗压强度达到最大值46.05 MPa;硝酸镍掺量为0~3%（质量分数）时,水泥的抗压强度随着镍离子掺量的增加而逐渐减小,当硝酸镍掺量由0增加到3%时,水泥7 d的抗压强度降低了约29%。水泥的密实度与铜镍离子的固化效果直接相关。在硝酸铜和硝酸镍掺量都为3%时,水泥1 d铜离子浸出质量浓度最高为1.95 mg/L、镍离子浸出质量浓度最高为0.97 mg/L,均远低于相关国家标准。铜主要以+2价态的Mg_0.95Cu_0.05O形式存在,镍主要以+2价态的Ni（OH）₂无定形沉淀形式存在。     

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.     

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.     

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。