煤中自由基热演化的模拟实验研究

有机质自由基的演化与温度有密切关系,因而可以作为古温标用于沉积盆地的热历史研究.利用36组热模拟实验得到了煤中自由基浓度与其镜质体反射率之间的关系,模拟实验的温度范围为300～550℃,模拟时间为30～480min.实验结果表明,煤中的自由基浓度随煤阶的增加而增大,大约在镜质体反射率为1.75%时达到最大值,随后自由基浓度开始下降.依据模拟实验得到的数据研究了煤中自由基浓度随时间和温度的变化关系,并建立了自由基浓度与时间—温度指数(TTI)的定量模式,该模式可以作为研究沉积盆地古地温的一种新方法.     

光度法测定常见蔬菜的抗氧化活性

在稀硫酸介质中,羟自由基迅速氧化丁基罗丹明B,使其褪色.在558 nm处测定吸光度的变化,可间接测定羟自由基的生成量;蔬菜提取物可以清除溶液中的羟自由基,从而使溶液的吸光度下降程度减弱.由此建立了一种测定蔬菜对羟自由基的清除率的新方法.测试了菠菜、油菜、香菜等10种蔬菜的抗氧化活性,其中菠菜、油菜、香菜的抗氧化活性较强.     

Surface Grafting of Polymers onto Nano-Sized Particles in Solvent-Free Dry-System and in Ionic Liquid

1 Introduction We have reported the grafting of various polymers onto the surface of inorganic nano-sized particles, such as silica, titanium oxide, and carbon black~([1]). The polymer-grafted nano-sized particles are known to have excellent properties, such as a good dispersibility in solvents and polymer matrices~([1, 2]). However, scale-up production of polymer-grafted nano-sized particles was hardly achieved, because complicated procedures, such as centrifugation, filtration, and solvent e…     

Synthesis of carbon nanotube arrays using ethanol in porous anodic aluminum oxide template

Carbon nanotube (CNT) arrays confined by porous anodic aluminum oxide (AAO) template were synthesized using ethanol as reactant carbon source at low pressure. Images by scanning electron microscope (SEM) and low magnification transmission electron microscopy (TEM) show that these CNTs have highly uniform outer diameter and length, absolutely controlled by the diameter and depth of nano-channel arrays of the AAO. High resolution transmission electron microscopy (HRTEM) imaging indicates that the graphitization of the CNT walls is better than the results reported on this kind of template-based CNT arrays, although it is not so good as that of multiwalled carbon nanotubes (MWCNTs) synthesized by catalysis. CNTs synthesized using acetylene as reactant gas show much less graphitization than those prepared using ethanol by comparing the results of HRTEM and Raman spectroscopy. The etchingeffects of decomposed OH radicals on the amorphous carbon and the roughness of AAO nano-channel arrays on the CNTs growth were employed to explain the graphitization and growth of the CNTs.     

某些自由基清除剂对哇巴因致豚鼠心律失常的影响——自由基可能参与洋地黄类的毒性过程

本文采用哇巴因致豚鼠心律失常模型,以哇巴目致室性早搏量、致室颤量和致死量作为衡量洋地黄类毒性的指标,观察GSH、三七皂甙Rg_1、Rb_1和AA等自由基清除剂对洋地黄美毒性的影响。结果表明:GSH、三七皂甙Rg_1、Rb_1和AA对哇巴因所致的心律失常均有不同程度的对抗作用,可减轻洋地黄类毒性。提示自由基可能参与洋地黄类的毒性过程。     

碱金属原子和OH三级反应速率常数研究

本文利用简化的单分子反应速率理论计算了低压下碱金属原子Na、K、Rb、Cs与OH 自由基反应(A+OH+M→AOH+M)的三级速率常数(200—2000K),并给出了该速率常数与温度关系的简化表达式.     

The Numerical Simulation of Flow Field of Jet System

In this paper, the internal fluid motion of a jet system is described by the Navier Stokes mechanics equations. For the simulation of the motion, the penalty function finite element method is used, and the velocity vectors and stream function curves are obtained. Using the Prandtl theory, this paper derives the free jet velocity and the jet bunch width in a half-space, the latter of which is amended by experiment. The results obtained in this paper are applied to micro-type high pressure water jet cleaner and the ejector of rocket engine.     

Reaction of CH radical with O<Subscript>2</Subscript> by time-resolved FTIR spectroscopy

The Methylidyne radical, CH, plays a crucial role in several complex environments such as planetary atmos- pheres and interstellar clouds, and is one of the most im- portant and active intermediate in hydrocarbon flames[1]. The CH involving reactions, including chemiionization, oxidation of hydrocarbons, the soot formation[2—5], and especially the formation of prompt NO[6], are of funda- mental interest in combustion chemistry, owing to the high reactivity and the large enthalpy of formatio…     

Near-环的5/2型J-根

本文引进5/2型N-群并定义near-环N的5/2型J_(5/2)(N).有例子表明J_2(N)J_(5/2)(N),J_(5/2)(N)J_3(N).我们证明了J_(5/2)(N)是N的半素理想,N→J_(5/2)(N)是根映射以及J_(5/2)(I)=J_(5/2)(N)∩I,其中I是N=N_0的理想,而且是N的直和项.