992 resultados para 48-404
Resumo:
介绍了一套用于硅多条阵列探测器中的高密度多通道电荷灵敏放大器的研制和阵列探测器电子学的发展现状和工作原理,提出了设计原则和设计思路,特别介绍了一个新开发的用于硅多条探测器中的48路电荷灵敏前置放大器的设计和实际测量结果。它具有低成本、高密度的特点,好于1%的能量分辨和良好的长期稳定性。
Resumo:
采用开顶箱(OTC)法,研究了高浓度臭氧(80±8nmol·mol-1)熏蒸处理对蒙古栎叶片中总酚、类黄酮、单宁及丙二醛(MDA)含量的影响,使用1,1-二苯基苦基苯肼(DPPH)法测定了蒙古栎叶片的总抗氧化能力.结果表明:蒙古栎叶片中总酚、类黄酮、缩合单宁和MDA的含量都有所增加,其中总酚和缩合单宁含量分别增加了48.17%和26.77%,差异显著(P<0.05);类黄酮和MDA含量分别增加了24.66%和5.26%,差异不显著(P>0.05);蒙古栎叶片总抗氧化能力显著增强(P<0.05),且与叶片中总酚和缩合单宁含量呈显著的正相关关系.
Resumo:
Nanocrystalline Pb(Zr0.52Ti0.48)O-3 was prepared from lead acetate, zirconium oxynitrate and titanium tetra-n-butoxide by a sol-gel method. It is found that both the crystallization temperature of precursor PZT and PZT product size were increased with increase of V(C3H8O2)/V(H2O) ratio in solution used. At V(C3H8O2)/V(H2O) = 4.47 the gel was formed moderately quick, and the nanocrystalline PZT with uniform granularity and low crystallizing temperature could be obtained. The diameter of the final nanocrystalline was ranged 60similar to70 nm as measured by atomic force microscopy (AFM). The crystallizing temperature of the precursor PZT was 443degreesC and the crystallization reaction was completed at 500degreesC by DTA and TG. The sol-gel reaction process was monitored by FT-IR and XRD.
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。