化学团聚作用对烧结微细粉尘除尘效率的影响

工业烟气中粒径10μm以下的微细颗粒物通过静电除尘器捕集效率较低,以烧结烟气中微细粉尘为研究对象,采用化学团聚协同作用提高静电除尘效率。选取聚丙烯酰胺(PAM)、葡甘露聚糖(KGM)和聚合氯化铝(PAC) 3种絮凝剂考察其团聚效果。结果表明,化学团聚作用显著增大了微细颗粒平均直径,其中PM10粒级的颗粒体积分数最高减少了75. 608%; 3种絮凝剂中KGM团聚效果最好,团聚前、后粉尘峰值粒径分别为11. 565、37. 825μm;在选取的浓度范围内,絮凝剂质量浓度越高团聚效果越好;烟气温度变化对PM2. 5级别颗粒团聚效果的影响不是很显著。通过正交试验分析得出,当入口烟温为100℃、絮凝剂KGM质量浓度为0. 1 g/L时,粉尘颗粒物峰值粒径达到40μm左右,除尘效果可达到97%以上。     

超临界快速膨胀法制备植物甾醇超细微粒

通过药物颗粒的微细化,降低其粒度,增大比表面积,进而提高药物颗粒的溶解度,可以有效地改善难溶药物的生物利用度。该文采用超临界流体快速膨胀法(RESS)微细化植物甾醇颗粒。利用SEM分析了沉淀颗粒的形貌及粒径大小。分析了过程参数与所制备颗粒粒度的关系。研究发现,当喷嘴内径Dn从60μm减小到40μm,植物甾醇颗粒粒径由10～20μm减小为5μm;预膨胀压力p0从15MPa增加到25MPa时,颗粒粒径由10～15μm降至5μm;预膨胀温度T0由318K升高到333K时,颗粒粒径由5～10μm减小为1μm,粒径分布也趋于均匀。喷嘴温度Tn对粒径无显著影响。该法制备得到1～20μm无定形植物甾醇微细颗粒,且具有更高的溶解速率,比原料植物甾醇早3h达到饱和溶解度。     

机制砂中石粉粒径及颗粒分布对胶砂性能的影响

通过对机制砂石粉自身特性,包括细度、粒径和颗粒级配分布对机制砂胶砂流动度、胶砂力学性能的影响的研究,从而对机制砂石粉的关键粒径和最优颗粒级配进行了界定。研究结果表明,45μm为石粉的关键粒径,45μm以下石粉含量以及石粉的颗粒分布对于机制砂胶砂性能影响都十分显著;机制砂整体石粉含量为20%时,机制砂中45μm以下石粉含量为5%,45~75μm石粉含量为10%,机制砂都能获得最佳的胶砂流动度和强度。     

新疆油田采出水中固体悬浮颗粒结构和性能研究

多种表征手段结合,研究了新疆油田矿场采出水中固体悬浮颗粒的结构及理化性质,实验结果表明:该矿场采出水中固体悬浮颗粒含量小于80 mg/L,粒径较大颗粒(10μm)占总颗粒的85%以上;加入絮凝剂聚氯化铝后,大量颗粒发生沉降,粒径较大颗粒(10μm)占总颗粒的95%以上,而粒径较小颗粒含量不足5 mg/L;不同粒径分布区间颗粒的Zeta电位不同,较小粒径颗粒(5μm)的Zeta电位较高,溶液状态较为稳定;加入絮凝剂后,Zeta电位降低,导致较小粒径颗粒易于发生沉降;结合电感耦合等离子体发射光谱、X射线荧光及元素分析,可知该固体悬浮颗粒中含有8种非金属元素和22种金属元素,元素C、O、Ca含量最高,加入絮凝剂后,元素Al和一些二价金属元素含量增高;X射线衍射表征技术表明颗粒主要以碳酸钙的方解石和文石以及卤化物形态存在。     

水泥颗粒组成的统计数据分析

对34个中小水泥企业的工业产品进行了水泥颗粒分析,并检验了样品的抗压强度。采用排序法分析了水泥颗粒特征粒径、平均粒径、均匀性系数、特征粒径与均匀性系数的乘积、<10μm颗粒组成及<35μm颗粒组成等指标与其对应强度的关系。研究表明:我国水泥产品的颗粒组成趋于合理,但>60μm的粗颗粒含量平均为10.8%,仍然偏粗。对水泥工业产品而言,特征粒径与均匀性系数的乘积值与强度有较好的相关性。<10μm组分含量是影响3d抗压强度的重要因素;<35μm组分含量是影响28d强度的主要因素。     

磷渣颗粒级配与磷渣水泥强度的关系

将3个工厂的磷渣,按粉磨时间序列处理成若干不同颗粒级配的试样,配制成一系列磷渣硅酸盐水泥(磷渣掺量均为30%),进行胶砂强度检验。采用灰色关联分析方法研究磷渣各粒径范围颗粒含量与水泥强度之间的关系。结果表明,磷渣中含磷量不同,磷渣的颗粒分布对水泥各龄期强度的影响也有很大差异,即磷(P2O5)质量分数为3.5%,粒径<10μm的磷渣颗粒对强度有削弱作用;磷(P2O5)质量分数为1.44%,粒径<10μm的磷渣颗粒对强度有增强作用;磷(P2O5)质量分数为2.64%,粒径<10μm的磷渣颗粒对3d强度有削弱作用,而对28d强度有增强作用。     

煤矸石颗粒群分布与煤矸石水泥活性的关系研究

本文将纯硅酸盐水泥、煤矸石按不同的粉磨时间序列处理成若干个不同颗粒群分布的试样,配制成一系列煤矸石硅酸盐水泥(煤矸石掺量均为30％),进行胶砂强度检验。采用灰色关联分析方法研究了煤矸石各粒径范围颗粒含量与煤矸石水泥强度的相互关系。结果表明:(1)煤矸石粒径在10μm以下的颗粒体积百分数与煤矸石水泥的强度均为正关联,而大于10μm的颗粒与煤矸石水泥的强度均为负关联,说明小于10μm的颗粒对强度增长有积极贡献;而大于10μm的颗粒对强度增长不利。(2)R-R分布表明:在煤矸石达到一定细度的条件下,宽分布试样有较多的小于10μm颗粒。     

石膏旋流器分离性能的试验研究

通过对影响水力旋流器分离性能的三个因素:底流管径、进料浓度和入口压力进行正交试验,得出影响旋流器分离效果的各因素主次顺序,并对各影响因素进行分析。通过分级实验得出,经分离后底流口颗粒粒径集中于20μm以上,溢流颗粒粒径则集中于20μm以下。随着颗粒粒径的增大,分离效率也在增大,当粒径达到30μm时,效率已经接近100%,旋流器起到明显的分级、增浓效果。     

进料位置与风速对旋风分级器颗粒分级效果的影响

根据旋风分级器内气流速度分布特点进行了进料区域划分,运用非稳态离散相模型和分级实验对比了3个代表性进料位置对颗粒运动轨迹及分级精度的影响,分析了1μm和10μm颗粒在不同区域内的受力情况。结果表明,边壁区域进料造成粗组分中细粉夹带现象严重,分级精度差;中部进料区域内流场强度大,粗颗粒受离心力强,细颗粒受轴向气流曳力大,有利于减少颗粒在分级区的停留时间,实现粗、细颗粒的快速分级,对改善分级精度有利;中心位置进料延长了粗颗粒的分级运动路程,增加了粗组分跑损的概率,模拟计算15μm的粗颗粒进入细组分的质量分数达到11.7%。经实验验证,入口气速在10~22 m·s~(-1),中部区域进料时分级后粗、细组分粒度分布曲线重合区面积最小,分级粒径比率值平均提高了25.3%,研究结果为离心气流分级设备的进料位置设计提供了一定的指导。     

分散染料粒径及分布对聚乳酸纤维混纺织物染色性能的影响

测定了C.I.分散蓝56等6种染料的上染百分率。系统地研究了影响C.I.分散蓝56分散稳定性的因素。测定了染料颗粒重量平均粒径Dw,重量比表面积Sw。应用JL9200激光粒度仪,测试进口DyStar Dianix嫩黄XF染料平均粒径约为0.85μm;染料颗粒粒径分布服从正态分布,粒径小于0.98μm的染料颗粒约占85%。对比两种国产染料的粒径测试发现都在1.6μm以上,累积平均粒径基本在8～10μm之间,是进口染料9倍,且分布不均匀。通过研究分散染料粒径与染色性能关系,选取了球磨工艺条件,得到均匀稳定分散染料液体。用研磨改进细度后分散染料染色,上色率平均提高7%以上。     

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.     

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。     

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.     

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.