Purification of Multiwalled Carbon Nanotubes and Characterization of Their Oxygen-Containing Surface Groups

Corresponding author. Email: [email protected].[中文文摘]用兼具酸性和氧化性的HNO3水溶液可方便地除去残留在原生态多壁碳纳米管(CNT)上的Ni-MgO催化剂组分,同时在其表面产生某些含氧官能团,使原生态多壁碳纳米管的疏水性表面变为亲水性表面.采用Boehm中和滴定法以及X射线衍射(XRD)、热脱附谱(TPD)、傅里叶变换红外(FTIR)光谱和X射线光电子能谱(XPS)等技术对HNO3处理过的多壁碳纳米管的相组成和表面含氧官能团进行测量和表征.结果表明:所生成表面含氧官能团的总量以经7.0mol·L-1硝酸378K处理24h的CNT为最高;3种主要表面含氧官能团的含量高低顺序为,羧基>内酯型羧基>酚型羟基.[英文文摘]We conveniently removed the Ni-MgO catalyst components from an as-grown multiwalled carbon nanotube (CNT) using an aqueous HNO3 solution with strong acidity and oxidizability as a purifying reagent. Some oxygen-containing surface groups were generated at the CNT surface, which converted the hydrophobic surface into a hydrophilic surface. The phase composition and the oxygen-containing surface groups of the CNTs treated by nitric acid were determined and characterized using Boehm′s neutralizing titration method and X-ray powder diffraction (XRD), temperature-programmed desorption (TPD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. The results indicated that the total content of the formed oxygen-containing surface groups was the highest for the CNTs treated with 7.0 mol·L-1 aqueous HNO3 at 378 K for 24 h. The content of the three major oxygen-containing surface groups was: carboxyl>lactonic carboxyl>phenolic hydroxyl.国家重点基础研究发展规划项目(973)(2009CB939804);福建省重大科技专项专题项目(2009HZ0002-1

Ecotoxicological Effects of Lead and Copper on Seed Germination of Wheat

通过种子萌发试验,研究了不同浓度的Pb2+和Cu2+对小麦种子萌发、幼苗生长以及对小麦α-淀粉酶活性的生态毒理效应。结果表明:Pb2+在低浓度下(5Mg·l-1)对小麦种子萌发过程中的各项指标皆为抑制作用;Pb2+、Cu2+胁迫对小麦α-淀粉酶活性存在低浓度激活和高浓度抑制的效应,且浓度越高,抑制作用越强;Cu2+对小麦种子萌发各项指标的抑制率大于Pb2+,Pb2+、Cu2+对小麦根生长的毒害作用大于对地上部的影响。By seed germination experiments, We studied ecotoxicological effects of Pb2+, Cu2+ on the seed germination, seedling growth and α-amylase activity of wheat.The results showed that the seed germination and seedling growth of wheat could be promoted at low concentrations of Pb2+ (under 0.5 mg·L-1), while they would be inhibited when the concentration of Pb2+ was high; Cu2+ in high concentrations (above 5 mg·L-1) could reduce the germination rate, the seedling growth and vigor markedly; the activity of α-amylase could be enhanced at low concentrations of Pb2+ or Cu2+ but be inhibited at high concentrations, and the injury became severer with the increase of concentration; the inhibition of Cu2+ on seedling growth indices of wheat were larger than that of Pb2+, the stress effects of Pb2+ or Cu2+ was stronger on seed germination than seedling growth.国家高技术研究发展计划(863计划)项目(2007AA10Z441);上海市科委项目(07DZ12055);上海市科委项目(07JC14025

Effects of Cadmium Stress on Seed Germination and Seedling Growth of Dwarf Beans

为比较系统地探讨Cd2+的生物毒性,作者以水培法研究了不同浓度的Cd2+溶液对四季豆种子萌发和幼苗生长发育过程中植物外部生长指标及内部生理生化变化的影响。结果表明:当Cd2+浓度较低时,Cd2+对种子萌发及幼苗生长发育毒害作用较小,一定浓度范围内(0.05~0.5Mg/l)还有促生作用,高浓度Cd2+(5~100Mg/l)能严重抑制四季豆幼苗根及下胚轴的生长;Cd2+胁迫对四季豆幼苗体内过氧化物酶(POd),超氧化物歧化酶(SOd),过氧化氢酶(CAT)活性存在低浓度激活和高浓度抑制的效应,且同一浓度的Cd2+对四季豆幼苗POd、CAT活性的抑制作用表现为根系大于下胚轴,Cd2+浓度>0.5Mg/l时,根系SOd活性大于下胚轴中的活性;Cd2+胁迫下,四季豆下胚轴和根的丙二醛(MdA)含量增加,且根部含量大于下胚轴的量。Cd2+对矮生四季豆种苗生长发育的影响因Cd2+浓度及幼苗部位的不同而异。In order to explore the biological toxicity of Cd2+more systematically, the effects of Cd2+ on the external and internal physiological and biochemical changes in the process of dwarf beans seed germination and seedling growth were studied with hydroponic culture experiments.The results showed that when the concentration of Cd2+ at low level, the effects of Cd2+ on the seed germination and seedling growth were not significant.Seeds germination were activated at a certain extent when Cd2+ concentration ranged from 0.05mg/L to 0.5 mg/L concentrations.The roots and Hypocotyls of seedling exhibited a significant decrease in growth at higher level of Cd2+ concentrations (5～100mg/L).The activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT)could be enhanced at low Cd2+concentrations but inhibited at higher concentration.The activities of POD, CAT were more inhibited in roots than in Hypocotyls at the same Cd2+ concentrations, while that of SOD was higher in roots than in Hypocotyls when the concentration of Cd2+ was more than 0.5mg/L.The malondialdehyde (MDA) contents were continuously increased with Cadmium exposure in both roots and Hypocotyls.The effects of Cd2+on the dwarf beans’growth were varied with the concentration of Cd2+ and the parts of plants.“2007AA10Z441”项目的资助;“07JC14025”项目的资助;“07DZ12055”项目的资

基于移相相与获取皮秒精度窄脉宽TTL信号的方法

 本发明涉及距离选通成像技术领域,公开了一种基于移相相与获取皮秒精度窄脉宽TTL信号的方法。该方法使用多路发生器使距离选通中的每路TTL脉冲触发信号(包括脉冲激光器触发信号和ICCD的触发信号)一分为二,形成两路相位和幅度完全相同的时序信号；采用皮秒级精度延时线技术对分路后的其中一路信号进行延时,使两路信号产生相移；然后使这两路信号经过逻辑与门,进行逻辑相与操作,从而压缩脉宽。本发明通过对两路信号相移的精确控制可以得到高精度的脉宽信号和脉宽压缩精度,压缩的脉宽可以接近TTL信号的极限,即1ns量级,可用于距离选通三维成像和水下成像等有高精度时序要求的选通应用领域

基于人眼视觉的直视型微光成像系统MRC模型

首次将最小可分辨对比度(MRC)的概念引入到了直视型微光成像系统.在人眼视觉的基础上,从信号检测的角度出发,推导出了直视型微光成像系统的MRC模型.该模型综合考虑了空间因素和时间因素对成像系统的影响,给出了系统在不同目标照度、不同对比度情况下探测图像时的极限灵敏阈.模拟结果表明,由此得到的直视型微光成像系统的极限分辨率与实际系统给出的分辨率基本一致,是一种能更全面地评价微光成像系统性能的模型

基于人眼视觉的直视型微光成像系统MRC模型

首次将最小可分辨对比度(MRC)的概念引入到了直视型微光成像系统.在人眼视觉的基础上,从信号检测的角度出发,推导出了直视型微光成像系统的MRC模型.该模型综合考虑了空间因素和时间因素对成像系统的影响,给出了系统在不同目标照度、不同对比度情况下探测图像时的极限灵敏阈.模拟结果表明,由此得到的直视型微光成像系统的极限分辨率与实际系统给出的分辨率基本一致,是一种能更全面地评价微光成像系统性能的模型

基于距离选通的激光成像同步控制系统

 本发明公开了一种基于距离选通的激光成像同步控制系统,该系统包括计算机软件界面、USB接口、微控制器、FPGA、外围电路、延时精调电路、PCB板和运算放大器,其中,从计算机软件界面发送出来的数据经USB接口传送至微控制器；微控制器将脉冲激光器和ICCD各自触发信号的频率、脉宽参数和这两路触发信号的延时和相互延时的控制参数传至FPGA；FPGA接收到这些控制参数后,产生触发脉冲激光器和ICCD的具有频率可调、脉宽可调、延时和交互延时可调(粗调)的两路TTL信号,这两路信号再经延时精调电路后实现延时和交互延时的精调,最终触发脉冲激光器和ICCD。利用本发明,达到能够灵活设置成像参数的目的,并且结构紧凑,便于搬运,使用方便,稳定性好

一种链霉菌发酵代谢产物新奥霉素的分离提取方法

本发明公开一种链霉菌发酵代谢产物新奥霉素的分离提取方法，方法包括：首先将发酵液先加热升温至60℃，杀灭发酵液中的链霉菌活菌体，通过滤布或陶瓷微滤膜除去新奥霉素发酵液中培养基固形物和菌体杂质后，除去固形物的发酵液经大孔吸附树脂吸附处理，然后，用阳离子交换树脂吸附富集大孔吸附树脂流出液中的新奥霉素，最后，采用0.5‑5.0％氨水进行解析、浓缩，制成新奥霉素母液，或添加载体，烘干制成粉剂。本发明提供了一种新的低成本制备新型生物农药新奥霉素母药或制剂的方法