39 resultados para 48-404
Resumo:
一种制备巯基官能化MCM-48介孔分子筛的方法是将巯丙基三甲氧基硅烷溶解于甲苯中,再加入经过焙烧的MCM-48分子筛,回流12~24小时;产物经离心分离后,用甲苯洗涤直至无未反应的巯丙基三甲氧基硅烷存在,于100℃-120℃下烘干,得到巯基官能化的MCM-48分子筛;具有巯基官能化的产品具有三维孔道结构,不易堵塞,对汞离子的吸附效果好的优点。
Resumo:
本发明公开了一种MCM-48介孔分子筛的制备方法,按原料组成质量百分比将3.1~16.8%的十六烷基三甲基溴化铵和0.75~1.63%的氢氧化钠溶解在66.4~87.1%的去离子水中,在强烈搅拌下缓慢加入正硅酸乙酯,继续搅拌反应30分钟后,转移至密闭反应器中在80~150℃晶化1~3天后,加入HCl调节pH值到6~9,再在80~150℃继续晶化2天;将晶化产物经过滤、洗涤、晾干后,在550℃下焙烧6小时,得到MCM-48分子筛。分子筛的产率高达97%,BET比表面积达到1137m↑[2]/g,孔径为2.6纳米左右,该制备方法简单、易操作。
Resumo:
We report on the preparation of luminescent silica mesoporous molecular sieves (MCM-48) activated by the europium complex Eu(DBM)(3) . 2H(2)O (where DBM = dibenzoylmethane), using a simple wet impregnation method. Different concentrations of Eu(DBM)(3) . 2H(2)O were introduced into the MCM-48 cubic structure, and the resulting samples were washed with ethanol for different times. UV-Vis absorption measurements and thermogravimetric analysis were used to estimate the amount of Eu complex that has been incorporated within the pores of the MCM-48 host. The various samples were characterized by X-ray powder diffraction (XRD), infrared spectroscopy, diffuse reflectance (DR) and fluorescence measurements. The results reveal that Eu complexes have been successfully introduced into the pores of MCM-48 without disrupting the structure. All the impregnated MCM-48 materials show the typical red luminescence of Eu3+ when excited with a UV lamp. Shifts of the absorption maxima were observed in the DR and fluorescence excitation spectra and will be discussed in relation with guest-host interactions between the organic complex and the silica matrix. The decay profiles of the europium luminescence in the different samples were also measured and discussed.
Resumo:
中国科学院山西煤炭化学研究所
Efficient synthesis of high-quality MCM-48 silicas through mixed surfactants and pH adjustment route
Resumo:
以醋酸铅 ,硝酸氧锆 ,钛酸四丁酯为原料用溶胶 -凝胶法制备了纳米 Pb( Zr0 .52 Ti0 .48) O3 ( PZT)。结果表明 ,随溶剂中乙二醇单甲醚与水的比例的增大 ,PZT粉体的晶化温度增高 ,晶粒的粒径尺寸也增大 ,当V( C3 H8O2 ) / V( H2 O) =4 .4 7时 ,不仅凝胶完成时间短 ,且可得到粒度分布集中、晶化温度低的 PZT粉体。用原子力显微镜测定 PZT的粒径为 6 0~ 70 nm,用 TG-DTA分析确定在 4 43℃即可发生晶化反应 ,在 5 0 0℃下结晶完善。通过对不同温度下热处理的粉体的红外光谱和 X射线衍射的分析 ,对溶胶 -凝胶法制备 PZT粉体形成钙钛矿结构的过程进行了研究。
Resumo:
采用活体注射秋水仙碱制备鱼类肾细胞染色体、PHA肌肉注射制备肾细胞染色体和鱼类早期胚胎制备染色体等多种方法。以空气干燥法制片Giemsa染色,对鲻鱼Mugil cephalus Linnaeus、真鲷Pagrosomus major(Temminck et Schlegel)、黑鲷Sparus macrocephalus(Basilewsky)、黑鮶Sebastes schlegeli (Hilgendorf)、石鲽Kareius bicoloratus (Basilewsky)、牙鲆Paralichthys olivaceus (Temminck et Schlegel)等分属四目、五科的六种海产鱼的染色体组型进行了考察和分析。研究结果表明:1、一般活体注射秋水仙碱制备海产鱼肾细胞染色体方法的有丝分裂指数虽然略低于PHA制备肾细胞染色体方法的有丝分裂指数。但它是最快最简便且很有效的方法,利用鱼类早期胚胎制备海产鱼染色体标本的方法也很有效,但要受到生物季节的限制。2、通过对六种海产鱼染色体组型分析得到,鲻鱼为48条端部着丝点染色体;真鲷的二倍体2n=48,有1对亚端部着丝点染色体。其余全部为端部着丝点染色体;黑鲷的二倍体2n=48。有3对中部着丝点染色体。2对亚中部着丝点染色体,其余全部为端部着丝点染色体。黑鮶的二倍体2n=48,有1对中部着丝点染色体,其余全部为端部着丝点染色体,石鲽的二倍体2n=48。全部为端部着丝点染色体;牙鲆的二倍体2n=48,全部为端部着丝点染色体。本文还对鱼类染色体的多态现象以及染色与进化的关系进行了讨论。