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由1,10-邻菲咯啉合成1,10-邻菲咯啉-5,6-二酮反应的副产物的形成与控制研究表明,1,10-邻菲咯啉在5,6位二酮化反应中的副反应产物及主产物分离时产生的副产物均为4,5-二氮杂芴-9-酮,二酮化反应条件(包括作为氧化剂的强混合酸H2SO4/HNO3的加入量、时间和温度)和主产物分离时体系的酸度对副产物的形成有重要影响,优化了二酮化反应条件和产物分离时的体系pH控制范围。在此优化条件下,可有效控制副产物的形成,使主产物1,10-邻菲咯啉-5,6-二酮的收率达到92%以上。 相似文献
74.
Hui Xie Yanyan Niu Ying Deng Hui Cheng Chengxiang Ruan Guangjiu Li Wei Sun 《中国化学会会志》2021,68(1):114-120
In this paper, an electrochemical aptamer sensor was proposed for the highly sensitive detection of mercury ion (Hg2+). Carbon nanofiber (CNF) was prepared by electrospinning and high‐temperature carbonization, which was used for the loading of platinum nanoparticles (PtNPs) by the hydrothermal method. The Pt@CNF nanocomposite was modified on the surface of carbon ionic liquid electrode (CILE) to obtain Pt@CNF/CILE, which was further decorated by gold nanoparticles (AuNPs) through electrodeposition to get Au/Pt@CNF/CILE. Self‐assembling of the thiol‐based aptamer was further realized by the formation of Au‐S bond to get an electrochemical aptamer sensor (Aptamer/Au/Pt@CNF/CILE). Due to the specific binding of aptamer probe to Hg2+ with the formation of T‐Hg2+‐T structure, a highly sensitive quantitative detection of Hg2+ could be achieved by recording the changes of current signal after reacting with Hg2+ within the concentration range from 1.0 × 10?15 mol/L to 1.0 × 10?6 mol/L and the detection limit of 3.33 × 10?16 mol/L (3σ). Real water samples were successfully analyzed by this method. 相似文献
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Zhi-Cheng Wang Wan-Tong Li Shigui Ruan 《Journal of Dynamics and Differential Equations》2008,20(3):573-607
In this paper, we study the existence, uniqueness and stability of traveling wave fronts in the following nonlocal reaction–diffusion
equation with delay
Under the monostable assumption, we show that there exists a minimal wave speed c* > 0, such that the equation has no traveling wave front for 0 < c < c* and a traveling wave front for each c ≥ c*. Furthermore, we show that for c > c*, such a traveling wave front is unique up to translation and is globally asymptotically stable. When applied to some population
models, these results cover, complement and/or improve a number of existing ones. In particular, our results show that (i)
if ∂2
f (0, 0) > 0, then the delay can slow the spreading speed of the wave fronts and the nonlocality can increase the spreading
speed; and (ii) if ∂2
f (0, 0) = 0, then the delay and nonlocality do not affect the spreading speed.
相似文献
78.
本文通过对La1/3Sr2/3Fe1-xCoxO3系列样品进行X射线衍射(XRD)和变温电阻率(p~T)、比热(C~T)、磁化率(M~T)等测试,研究了Co掺杂对该系列样品的晶体结构和电热磁性质的影响.结果表明,随着Co掺杂量的增加,晶胞体积单调减小;电阻中电荷有序(charge ordering,CO)的特征逐渐消失.Co含量低的样品随着温度降低发生顺磁-反铁磁(PM-AFM)转变和金属-绝缘体(M-I)转变;Co含量高的样品则在磁转变温度以下表现出团簇玻璃型短程铁磁有序行为,并且在整个测量温区内具有金属导电特性.这些证明Co掺杂引起电子的局域化效应是导致体系电磁和输运行为发生变化的主要原因. 相似文献
79.
<正>Cr ion implantations in glass with the different doses of D=1.493×10~(17) and 4.976×10~(17) ion/cm~2 are obtained by metal vapor vacuum arc(MEVVA).The effects of the different Cr ion implanted doses on terahertz(THz) transmission property are analyzed from THz time-domain spectroscopy.The results show that the more the Cr ion implanted dose in the micro-area implantation glasses,the larger the THz transmission except the larger absorption at 0.24 THz.This is an effect attributed to the coupling of plasmas on both the implantation and the implantation affected zones of the Cr ion implantation glass. 相似文献
80.
A series of novel ruthenium-manganese oxide (denoted as RunMn1−nOx) has been formed by oxidative co-precipitating. The precursor was obtained by mixing Mn(VII) (potassium permanganate), Mn(II) (manganese acetate) and Ru(III) (ruthenium chloride) in neutral aqueous solution at room temperature. The powder of RunMn1−nOx was obtained by calcinating the precursor at appropriate temperature. The crystalline structure and electrochemical performance of the powder have been studied as a function of the calcination temperature. At appropriate calcination temperature (e.g. 170 °C), the powder is in hydrous amorphous phase with a high specific capacitance. When the calcination temperature reaches up to 350 °C, the crystal form of α-MnO2 is formed, but the ruthenium oxide still keeps amorphous structure, which will lead to the decrease of specific capacitance of the composite electrode materials. The X-ray photoelectron spectroscopy (XPS) analysis shows that the powder of RunMn1−nOx prepared in this study belongs to the composite of RuO2-MnO2. The results from cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS) indicate that the ruthenium weight density of 9 wt% in RunMn1−nOx can improve the cost-performance of ruthenium-manganese composite electrode. 相似文献