褐藻多糖铈配合物对质粒DNA及牛血清白蛋白的裂解作用

以褐藻糖胶、褐藻酸及褐藻演粉为配体，分别与四价的铈（Ce^4 ）结合，形成了水溶性的褐藻多糖铈配合物，在生理中性条件下，它们对牛血清白蛋白（BSA）均有一定的裂解作用，但对质粒DNA（Plasmide DNA）仅有褐藻淀粉铈配合物有非常明显的裂解作用。     

关于N-苯基-萘胺的光分解过程

采用ESR方法研究了α-和β-N-苯基取代萘胺在苯溶液中的分解过程及其反应中间体.结果表明,有三种自由基被检测到,即H,C₁₀H·₇和C₆H·₅(H)N·自由基.其中值得注意的是萘自由基的生成,这意味着在一定的光解条件下,苯基萘胺分子中的C-N键可发生断裂,萘基可从氮原子上断裂下来.同时,通过调节自旋捕捉剂的浓度与添加光敏剂,可以明显地改变三种自旋捕获物的相对生成比例,借此得到三种自由基结构与光稳定性的信息.此外,本文还结合量子化学的计算讨论了此光解过程各种自由基生成的可能性.     

壳聚糖辐射效应的研究（Ⅰ）──辐照剂量与分子量的关系及辐射裂解的G（S）值

通过粘度的测量，考察了壳聚糖在不同条件下经不同剂量γ射线辐照所引起的分子量的变化，并分别计算了真空和空气中壳聚糖辐射裂解的Ｇ（Ｓ）值。     

不同脱铝深度稀土超稳Y沸石的催化性能的研究

本文选择正庚烷、正十六烷、环己烯和α-甲基萘作为探针分子考察了四种脱铝深度的稀土超稳Y沸石对短链烃、长链烃、单环烯烃和多环芳烃的催化性能,同时将催化性能与稀土超稳Y沸石的酸性关联起来。结果表明:四种沸石对各种探针分子的裂解活性依次为正十六烷>正庚烷>α-甲基萘>环己烯。对单个探针反应,除REUSY-38外,其余样品的裂解活性和选择性均与骨架铝有关而与非骨架铝无关;裂解活性随(N_(AI))_E的减少,酸强度的增加而增加,即REUSY-2>REUSY-2m>REUSY-1。反应温度的升高和脱铝深度的加深,都会导致探针反应的裂解深度的增加。     

Raman Spectrum of Epitaxial Graphene on SiC （0001） by Pulsed Electron Irradiation

We report new Raman features of epitaxial graphene （EG） on Si-face 4H-SiC prepared by pulsed electron irradiation （PEI）. With increasing graphene layers, frequencies of G and 2D peaks show blue-shifts and approach those of bulk highly-oriented pyrolytic graphite. It is indicated that the EG is slightly tension strained and tends to be strain-free. Meanwhile, single Lorentzian line shapes are well fitted to the 2D peaks of EG on SiC（O001） and their full widths at half maximum decrease with the increasing graphene layers, which indicates that the multilayer EG on Si-face can also contain turbostratic stacking by our PEI route instead of only AB Bernal stacking by a traditional thermal annealing method. It is worth noting that the stacking style plays an important role on the charge carrier mobility. Therefore our findings will be a candidate for growing quality graphene with high carrier mobility both on the Si- and C-terminated SiC substrate. Mechanisms behind the features are studied and discussed.     

浅谈中专学生物理学习的缺陷和应对途径

由于中专学生的学习动机、知识掌握水平与物理知识和技能的积累水平比较低,这在很大程度上困扰了中专物理老师的教学.要想彻底改变这种现状,老师一定要立足学生的学习乡长,从学生的实际出发,选择多种教学方式和教学手段,激发学生的学习积极性,树立他们学习成功的自信息,最终改善中专学生的学习物理状态.接下来,本文将根据笔者多年的中专物理教学经验,浅谈中专学生物理学习的缺陷和应对途径.     

初中物理课堂教学中培养学生的创新能力途径分析

随着新课程改革的逐渐深入,初中物理教学也有了很大的改革,初中物理教学的最终目的已经不再是像过去那样追求知识点的掌握与应用,而是注重对学生创新能力的培养.因此在知识经济时代的大背景下,初中物理教学的目标之一就是培养学生的创造性和创新能力,物理教师必须在课堂教学过程中巧妙运用科学的教学方法来实施创新教育,本文正是对这一问题展开了探讨.     

生物油催化裂解转化制取三苯

通过不同孔特征的分子筛(HZSM-5、HY沸石和MCM-41)实现生物油催化转化为三苯(苯、甲苯和对甲苯). 基于三苯的产率和选择性,芳香化合物逐次降低顺序为: HZSM-5>MCM-41>HY沸石.用HZSM-5催化裂解生物油产生芳香化合物的最大产率为33.1%,选择性为86.4%. 研究了反应条件对生物油催化裂解的影响,结合催化剂表征结果,讨论了催化剂的结构与性能之间的关系.     

煤油裂解产物/空气与煤油/空气在宽温度范围内点火延迟的对比研究

Kerosene is an ideal endothermic hydrocarbon. Its pyrolysis plays a significant role in the thermal protection for high-speed aircraft. Before it reacts, kerosene experiences thermal decomposition in the heat exchanger and produces cracked products. Thus, to use cracked kerosene instead of pure kerosene, knowledge of their ignition properties is needed. In this study, ignition delay times of cracked kerosene/air and kerosene/air were measured in a heated shock tube at temperatures of 657–1333 K, an equivalence ratio of 1.0, and pressures of 1.01 × 10⁵–10.10 × 10⁵ Pa. Ignition delay time was defined as the time interval between the arrival of the reflected shock and the occurrence of the steepest rise of excited-state CH species (CH*) emission at the sidewall measurement location. Pure helium was used as the driver gas for high-temperature measurements in which test times needed to be shorter than 1.5 ms, and tailored mixtures of He/Ar were used when test times could reach up to 15 ms. Arrhenius-type formulas for the relationship between ignition delay time and ignition conditions (temperature and pressure) were obtained by correlating the measured high-temperature data of both fuels. The results reveal that the ignition delay times of both fuels are close, and an increase in the pressure or temperature causes a decrease in the ignition delay time in the high-temperature region (> 1000 K). Both fuels exhibit similar high-temperature ignition delay properties, because they have close pressure exponents (cracked kerosene: τ_ign∝P^-0.85; kerosene:τ_ign∝P^-0.83) and global activation energies (cracked kerosene: E_a = 143.37 kJ·mol^-1; kerosene: E_a = 144.29 kJ·mol^-1). However, in the low-temperature region (< 1000 K), ignition delay characteristics are quite different. For cracked kerosene/air, while the decrease in the temperature still results in an increase in the ignition delay time, the negative temperature coefficient (NTC) of ignition delay does not occur, and the low-temperature ignition data still can be correlated by an Arrhenius-type formula with a much smaller global activation energy compared to that at high temperatures. However, for kerosene/air, this NTC phenomenon was observed, and the Arrhenius-type formula fails to correlate its low-temperature ignition data. At temperatures ranging from 830 to 1000 K, the cracked kerosene ignites faster than the kerosene; at temperatures below 830 K, kerosene ignition delay times become much shorter than those of cracked kerosene. Surrogates for cracked kerosene and kerosene are proposed based on the H/C ratio and average molecular weight in order to simulate ignition delay times for cracked kerosene/air and kerosene/air. The simulation results are in fairly good agreement with current experimental data for the two fuels at high temperatures (> 1000 K). However, in the low-temperature NTC region, the results are in very good agreement with kerosene ignition delay data but disagree with cracked kerosene ignition delay data. The comparison between experimental data and model predictions indicates that refinement of the reaction mechanisms for cracked kerosene and kerosene is needed. These test results are helpful to understand ignition properties of cracked kerosene in developing regenerative cooling technology for high-speed aircraft.