串联流化床反应器冷态实验研究

为了解决攀枝花高钙、镁钛精矿采用电炉冶炼之后所得的高钛渣的直接氯化问题,进行了快速流化床-湍流床-快速流化床三级串联组成的串联流化床反应器的冷态研究.测定了流化床颗粒的速度和浓度分布,研究了固相的停留时间和流动形态,对快速流化床的流化速度、湍流床的轴向浓度分布进行了考察,比较了湍流床和沸腾床对同样强度颗粒的碾碎率,结果证明了湍流床具有较高的抗粘结能力.     

流化床H—198催化剂丁烯氧化脱氢制丁二烯研究进展

本文对H-198催化剂在挡板鼓泡床、湍流床、快速床等反应器内催化情况进行了考察。研究证实,开发细颗粒、宽筛分适于较高流速操作的湍流床或快速流化床,对提高丁烯氧化脱氢制丁二烯有更高效果。     

循环流化床锅炉流体动力学研究

在循环流化床锅炉炉膛内，分为湍流床和快床２个区域，论述了由鼓泡流化床与从气力输送状态向循环流化术转化过程中的炉内流体动力学现象，研究了湍流床开始出现到完全转化为湍流化床及快床时，炉内气体速度变化的规律和相庆的计算公式。     

流化床压力脉动的递归分析

在自行搭建的冷态流化床实验台的基础上,采集了风帽入、出口处的压力脉动信号,通过对比、分析不同压力测点的压力信号递归图,来观察流化床内流化特性的差异。改变空气流量,借助递归率RR、确定性DET、递归熵ENTR,最长对角线Lmax、层状度LAM、竖直或水平线段长度均值TT等参数来定量分析鼓泡床、节涌床、湍流床和快速流化床4种流型的动力学特性。结果表明:递归定量分析能够有帮助于理解流化床的流动机理,对气固二相流的流型识别具有一定意义。     

丁烯氧化脱氢制丁二烯流化床反应器研究进展

基于 H—198催化剂丁烯空速为300～400h~(-1)的特性,我们开展了湍流流化床反应器及快速流化床反应器的基础研究和过程开发研究。研究证实,湍流流化床反应器或快速流化床反应器比鼓泡流化床反应器对于提高丁烯转化率,丁二烯收率具有更高的效果,为发展丁烯氧化脱氢制丁二烯开创了一条新的研究途径。     

循环流化床流体动力特性研究

循环流化床的设计和放大需要对其流动特性进行细致地研究,文章采用RSM模型对新型的双外循环流化床流场进行了三维的数值模拟,得到了在不同入射速度下的流化床主、副床的三维的速度分布、压强分布及湍流强度分布等,给出了主床在典型位置x方向的上分布图,并与实验结果进行了对比。结果表明,在不同入射速度下RSM模型数值模拟结果与实验结果符合均较好,模拟计算可以很好地反映流化床中真实的流动状况,可以用于反应过程的性能评价,为设备优化设计和相似放大提供依据。     

循环流化床颗粒浓度波动信号多重分形测度分析

由于循环流化床气－固两相流动规律相当复杂，使得至今对其流动规律的认知仍不足以直接用于循环流床的工业设计与放大。近十多年来，确定性混沌理论已被用于循环流化床动力学特性的研究，与其密切相关的分形理论也被用于流化床流动特性的研究。然而，这些研究所用均是采用单分形理论，而单分形理论对解释循环流化床复杂的非线性气－固流动行为显得能力不足。为了探讨循环流化床内颗粒流体系统非线性、非均匀性和混沌特性机理。本文引入不同测试多重分形分析的方法，用小波变换模极大值与多重分形测度分析方法相结合，检测循环流化床颗粒浓度波动信号奇异性并得出多重分形奇异谱。结果表明循环流化床颗粒浓度波动信号具有明显的多重分形特性。小波变换多重分形方法可以用来描述床内颗粒流动特性，为探讨循环流化床颗粒流体系统非均匀机制提出了一种新的方法。     

串行流化床内气固流动控制

针对化学链燃烧分离CO₂技术特点，在一串行流化床（循环床+喷动床）冷态实验装置上，以CaSO₄载氧体为实验原料（d_p= 0.6 mm），研究串行流化床气固流动特性。基于床内压力分布特征，提出将循环床（空气反应器）沿床高方向划分为鼓泡段和快速流化段2个流型区域，将喷动床（燃料反应器）沿床高方向划分为喷动段、鼓泡段和悬浮段3个流型区域，得出串行流化床内气固流动控制机理。研究并考察了循环床流化风速度、喷动床喷动风速度对串行流化床内反应器间（空气反应器和燃料反应器）气体串混、颗粒循环速率以及床层压降的影响。研究结果表明，流化风是床内颗粒循环的驱动力，流化风速度应控制在 3.77～4.05 m·s^-1；喷动风速度对床内颗粒循环以及系统稳定运行起着关键作用，建议将喷动风速度控制在0.42～0.56 m·s^-1。     

气-固流化床压力脉动递归图分析

引入递归图分析方法对具有混沌与分形特性的气-固循环流化床压力脉动信号进行分析,针对Logisitc模型比较了递归图特征量递归率、确定性、平均对角线长度、分叉性与最大Lyapunov指数之间的关系,得出了递归图特征量对于混沌特性具有表征作用的结论。研究了递归图特征量在气-固循环流化床不同床型下的变化规律,递归图特征量在固定床型、湍流床型、气力输送床型下保持稳定,在鼓泡床型、快速流化床型下分别迅速递增或递减,因此递归图特征量同样可以对循环流化床不同床型进行辨识。     

柱形流化床传热特性的数值模拟

对Shedid等搭建的圆柱体流化床采用欧拉?欧拉法进行三维数值模拟,考察了颗粒球形度、表观进气速度和床料初始堆积高度对流化床内垂直加热壁面与流动床料之间对流传热特性的影响,采用有效导热系数分别计算气相和固相的对流传热系数。结果表明,随表观进气速度增大,流化床内颗粒物料湍流运动加剧,加热壁面平均温度和流体平均温度下降,壁面流体间传热平均温度差减小,壁面流体间对流传热系数增大;随初始床料高度增加,流化床内颗粒与加热壁面的接触面积增大,导致固相平均对流传热系数增大。     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。