喷雾热解法制备Bi系超导粉末的研究

本文主要研究喷雾热解方法制备铋系超导粉末的工艺影响因素,实验结果表明溶液的浓度对雾化效率有很大影响;加热温度、空气的流量、雾滴的大小对颗粒的形状、大小、分布有较大的影响;通过改变喷雾热解参数,达不到使颗粒在热解过程中的完全分解的目的;控制热处理温度和气氛是控制物相的关键因素,在700℃,5 h,氮气气氛下可以得到铅完全固溶的2212相前驱体装管粉末.     

化学沉淀法制备YAlO3超微粉体

以碳酸氢铵为沉淀剂,金属硝酸盐为反应原料,采用化学沉淀法制备了YAlO3(YAP)超微粉体.通过XRD研究了硝酸盐溶液浓度、沉淀剂溶液的pH值、焙烧温度对生成粉体物相纯度的影响.结果表明:沉淀物中Y和Al两元素按物质的量比1∶ 1均匀混合是制备YAP纯相的关键, 前驱体在1200℃焙烧2h得到YAP纯相,较高焙烧温度及分步焙烧方式所得粉体相纯度较低.     

前驱体对熔盐法合成Bi2WO6光催化剂及其性能的影响

分别以Bi(NO3)3和Na2WO4溶液直接混合所得沉淀、加氨水所得沉淀及Bi(NO3)3×5H2O+Na2WO4×2H2O为前驱体,采用熔盐法合成Bi2WO6光催化剂粉体,研究了不同前驱体所制粉体的物相、形貌,以其为催化剂,在可见光照射下降解罗丹明B溶液. 结果表明,用后二者为前驱体均可得到薄片状纯相Bi2WO6粉体. 加氨水所得沉淀为前驱体所制Bi2WO6粉体的光催化性能最好,在可见光照射下对0.01 mmol/L RhB溶液的降解率在60 min内达99%.     

若干网络形成体对Bi系玻璃形成及性能的影响

本文研究了添加少量B_2O_3,Sio_2和P_2O_5等玻璃网络形成体对Bi-Sr-Ca-Cu-O系统玻璃形成能力、稳定性和性质的影响。结果表明:Bi在Bi系玻璃中主要以[BIO_3]三配位形式存在,该玻璃呈逆玻璃状态;晶化热处理后主晶相为85K的2212低温超导相,未发现110K的2223高温相;引入少量B_2O_3,SiO_2和P_2O_5能明显提高玻璃形成能力和稳定性,改变析晶程序,促进2223高温相生成;当同时加入少量Sb_2O_3时,则会降低玻璃熔融温度,加速2223高温相生成,改善其电磁性能。从玻璃结构和2223相形成机理对上述结果作了解释。     

新法合成碳酸锌纳米晶及其数据挖掘

以七水硫酸锌粉末与碳酸氢铵粉末作原料,在适量的表面活性剂(聚乙二醇 400)存在下,在室温下充分混合研磨得到反应混合物,洗去其中的可溶性无机盐后烘干,所得前驱体为结晶良好的纯相碳酸锌纳米晶,从而获得了一种简易的合成纳米氧化锌前驱体的新方法. 基于均匀设计、回归分析及最优计算,对纳米碳酸锌合成实验中得到的小型数据库作数据挖掘,所获取的优化工艺条件为：反应物摩尔比nNH4HCO3:nZnSO4·7H2O=1:1,表面活性剂用量20 μL,研磨时间40 min. 在此条件下合成的碳酸锌粉末及其在350℃煅烧2 h所得到的氧化锌粉末的一次粒子的平均粒径分别约35和20 nm.     

Bi_2Sr_2CaCu_2O_y超导晶体的多色性及其显微结构特点

应用透射电镜和光学显微镜研究了熔融急冷法制备的Bi系高温超导体的显微结构。首次报道了Bi系超导晶体具有明显的多色性。实验证明:针状超导晶体沿α轴择优生长。在试样表面异相成核生长的2212晶体垂直于外表面择优取向排列。     

BaFe_(12)O_(19)纳米粉体的制备与表征

利用Fe(OH)(HCOO)2和Ba(CH3COO)2为原料,C7H8O7.H2O为螯合剂,制得了均一的柠檬酸盐前驱体溶液,将所得的溶液进行喷雾干燥制得了含铁和钡的柠檬酸盐粉体。以制得的粉体为固相反应的前驱体,通过简单的固相分解反应制得了片状的BaFe12O19纳米粉体。同时利用高沸点的液体石蜡对前驱体进行预处理,进一步热分解,得到棒状的BaFe12O19纳米粉体。对前驱体进行了红外(IR)表征。利用热重(TG)技术和X射线粉末衍射(XRD)技术跟踪了前驱体的热分解过程并对所得产物的物相进行了确定。所得产物的形貌由透射电镜(TEM)给出。     

Bi2WO6花瓣状微球的无助剂合成及其光催化性能

以Bi(NO3)3·5H2O和Na2WO4·2H2O为原料,采用无助剂水热法合成了Bi2WO6花瓣状微球,利用扫描电镜(SEM)、X射线衍射(XRD)、紫外-可见漫反射光谱(UV-vis DRS)、N2吸附-脱附等温线等方法对Bi2WO6微球形貌与结构进行表征,以罗丹明B(RhB)为降解模型,考察了水热反应温度、水热反应时间和前驱体溶液pH值对Bi2WO6微球光催化性能的影响。结果表明:前驱体溶液pH值对Bi2WO6微球的光催化性能影响最大。前驱体溶液为酸性时,有利于花瓣状Bi2WO6微球的生成;前驱体溶液为碱性时,有杂质相Bi3.84W0.16O6.24生成。在适宜的水热反应条件(前驱体溶液pH值0.5,反应温度150℃,反应时间24 h)下,合成的斜方晶型Bi2WO6微球具有花瓣状形貌,微球直径为0.5~3.0μm,表面平均孔径为18.9 nm,比表面积为27.9 m2/g,氙灯(150 W)光照75 min,对20 mg/L的RhB脱色率可达100%,说明花瓣状Bi2WO6微球具有优良的可见光催化活性。     

一种印染废水处理材料的制备方法——马建锋;崔冰莹;李定龙.CN102335586A

本发明公开了一种印染废水处理材料的制备方法,在膨润土中加入盐酸或硫酸制成泥浆,和生石灰粉末混合,再加入十二烷基苯磺酸钠溶液中,沉淀分离,烘干,碾磨成粉末;将得到的粉末在剧烈搅拌下缓慢加入中性无机前驱体,焙烧得到多孔黏土异构材料粉末:浸泡于磷酸溶液中得到吸附有磷酸的粉末;将文蛤壳和醋酸混合反应,取上清液,将所得的     

C_uO对Bi(Pb)—Sr—Ca—Cu—O系微晶玻璃超导性能的影响

用DTA、XRD、SEM等手段研究了Bi_(0.7)Pb_(0.3)SrCaCu_xO_y(x=1.6,1.8,2.O,2,2.2.4)系统的晶化过程、晶相组成和晶体形貌,详细讨论了CuO对该系统高超导相2212、2223形成以及对超导性能的影响。研究结果表明:CuO含量的增加有利于超导相的形成,在CuO=2.0mol附近该系统超导性能呈现最佳值。     

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.     

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.     

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。