砂磨机湿法粉磨制备超细氧化锌粉体的研究

以粗颗粒氧化锌为原料,通过砂磨机湿法粉磨的方法制备超细氧化锌。用马尔文激光粒度仪、扫描电镜（SEM）对研磨前后的氧化锌粉体进行了表征。考察了分散剂种类及用量、pH、固含量、研磨时间对研磨效果的影响,得出最佳研磨条件：转速为3 000 r/min,固含量为15%（质量分数）,pH为11,聚乙二醇20000加入量为0.5%（质量分数）,研磨时间为40 min。在此条件下可以制备d₅₀约为6 μm、d₉₀为10 μm的超细活性氧化锌粉体。     

正交试验优化镨黄陶瓷色料超细研磨工艺参数

采用湿法介质搅拌磨超细研磨微米粒级镨锆黄色料,制备了亚微米粒级的水基悬浮液。试验以中位径d50及粒度分布均匀性系数n为指标,采用四因素三水平正交试验,获取研磨最优参数组合。最佳研磨参数为:固含量30wt%、介质填充率80vol%、搅拌线速度6.89m/s、研磨时间1.25h。     

水泥熟料的粉磨动力学研究

采用行星磨对水泥熟料进行不同时间段的研磨,通过测定粉磨产物的粒度分布、比表面积和45 μm筛余值,以Rosin-Rammler-Bennet(RRB)方程作为粒度分布模型,运用线性回归分析和粉磨动力学的特征粒径分析的方法,对熟料进行了粉磨动力学研究和粉磨性能评价.实验结果表明:经过研磨后,水泥熟料粉体的比表面积、特征粒径和均匀性系数与粉磨时间的对数或双对数呈线性关系,熟料的粉磨速度方程为dS/dt=170.66/t,且熟料粉磨细度不宜高于550 m~2·kg~(-1).     

采用高压辊磨和搅拌磨湿法超细研磨的研究

采用一种高压辊磨与搅拌磨的复合粉碎系统进行了湿法超细研磨碳酸钙物料实验研究.结果表明,碳酸钙物料经高压辊磨增加预磨次数一次,可使后续搅拌磨产出的产品中小于2 μm颗粒的百分比大约提高10%.另外,与单一搅拌磨湿磨所获得的产品细度相比,这种碳酸钙物料若经过高压辊预磨,能使后续湿法超细研磨所需能量降低10%～30%.为了说明复合粉碎系统中高压辊磨预磨的作用,讨论了各种不规则形状的颗粒受压时产生微裂隙的现象.颗粒经过高压作用后,其内部发生的压应力松弛后出现的微裂隙对后期粉碎作业有较大的影响.经模拟分析表明,受压颗粒内部裂隙的传播路径及其行为与材料的各向异性和应力分布有关.     

湿法球磨制备超细钴蓝粉体的研究

钴蓝颜料是重要的无机颜料之一.超细研磨是钴蓝生产中不可缺少的重要环节.本文就钴蓝颜料的湿法超细研磨进行了研究,对影响研磨效果的助磨剂品种及用量、介料比、料浆浓度、研磨时间等因素分别作了探讨,结果表明在l.0％六偏磷酸钠,介料比3∶1,料浆浓度25％,研磨时间24h的研磨条件下,能制得 d50 =0.78 μm并且均匀分布的超细钴蓝粉体.     

研磨设备和工艺参数对氧化锆粉体粒度的影响

为了研究不同研磨设备及研磨工艺参数对粉体团聚体的解聚效果,以d50=1.355μm的氧化锆粉体为研究对象,研究了研磨设备和工艺参数对氧化锆料浆粒度的影响。首先,分别采用立式球磨机、立式珠磨机和卧式砂磨机为研磨设备,以φ2 mm的氧化锆球作为研磨介质,以m介质∶m物料=5∶1的介质物料比研磨15 h后,检测研磨后氧化锆料浆的粒度。结果表明,卧式砂磨机的研磨效果最优,研磨后氧化锆料浆的d50=0.303μm。然后,采用卧式砂磨机为研磨设备,以φ2 mm的氧化锆球作为研磨介质,选择介质物料比(m介质∶m物料)、料浆固含量(w)、线速度和研磨时间作为试验因素,进行四因素三水平(m介质∶m物料分别为4∶1、5∶1和6∶1,料浆固含量(w)分别为35%、45%和55%,线速度分别为5、10和15 m·s-1,研磨时间分别为20、25和30 h)正交试验,检测研磨后氧化锆料浆的粒度。结果表明:采用卧式砂磨机为研磨设备,当介质物料比(m介质∶m物料)为4∶1,料浆固含量(w)为45%,线速度为10 m·s-1,研磨时间为25 h时,研磨效果最佳,研磨后氧化锆料浆的d50约为0.3μm。     

生料细度对易烧性和粉磨功耗的影响

通过对不同细度生料的易烧性及粉磨功指数进行试验研究后，得出当生料的80 μm细度小于17％时，f-CaO与生料细度呈指数关系，随着细度的变粗，f-CaO增加。生料细度每增减1％，f-CaO升高或降低0.1％。但是当80 μm细度大于17％时，f-CaO与细度的关系比较复杂，呈多项式分布。随着生料80 μm细度的减小，生料的粉磨功耗逐渐升高，物料难磨。当生料细度每降低1%时，生料粉磨功耗将增加0.1~0.2 kWh/t。生料中位径D50与粉磨功耗的关系式为：D50×Wi11.5=1.48×1015。     

西沟煤直接液化条件及超声对液化效果的影响

以新疆阜康西沟原煤(200目)为研究对象,四氢萘为制浆和供氢溶剂,利用正交及单因素实验确定西沟煤适宜的液化条件.结果表明,T=435℃,p=7 MPa,m(solvent)∶m(coal)=1.75∶1和t=60 min为适宜的液化条件.此条件下,rη(oil)=75.33％.进一步探讨了煤粒径及超声处理对液化效果的影响.西沟原煤经胶体磨研磨后直接液化:研磨1h,粒径9.98 μm,η(oil)=59.96％;研磨2h,粒径2.60 μm,η(oil) =60.03％;研磨3h,粒径1.10 μm,r(oil) =60.02％;研磨4h,粒径0.76 μm,η(oil) =60.06％.若研磨后先超声处理再液化,研磨1h,2h,3h和4h后油产率为80.73％,81.25％,84.27和82.63％,比不超声分别提高了20.77％,21.22％,24.25％和22.57％.     

搅拌磨湿法制备氧化铝超细粉的研究

以粗颗粒氧化铝粉为原料,采用搅拌磨湿法工艺制备了-5．0um颗粒产率为99．68％的氧化铝超细粉。按正交表L16（4^5）安排正交试验,通过方差分析确定了制备氧化铝超细粉的最佳球磨条件,并分析了各因素对球磨过程的影响程度。在本研究的实验条件下,制备氧化铝超细粉的最佳条件为：球磨质量分数50％、球磨时间10．0h、搅拌转速500r／min、球料比7：1。     

研磨体大小对水泥熟料粉磨动力学的影响

论文就球磨机中研磨体大小对水泥熟料的破碎速率、初始破碎分布函数和粒度分布规律进行研究,实验所用研磨体的尺寸为φ20 mm, φ30 mm和φ40 mm,物料为-1.70+1.18 mm粒级的水泥熟料.研究结果表明:不同大小的研磨体对水泥熟料的粉磨遵循一级粉磨动力学方程,破碎速率随研磨体尺寸增大;初步研究认为研磨体大小对初始破碎分布参数有一定的影响;粉磨较短时间如16 min以前,大尺寸研磨体(φ40 mm 和φ30 mm)粉碎得到的细粉量多于小尺寸研磨体(φ20 mm), 延长粉磨时间到32 min以后,三种研磨体粉碎得到的水泥熟料的粒度分布相当.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.