基于随机抽样法的多群核数据不确定性影响分析

基于随机抽样方法,研究多群核数据不确定性对反应堆物理计算的影响。首先利用SCALE软件包中核数据协方差矩阵和自主开发的随机抽样模块SAMP,得到多群微观截面等核数据的抽样值,之后分别使用SCALE/TRITON和PARCS程序进行组件计算及堆芯稳态计算,最后通过统计分析得到组件和堆芯计算结果的不确定度。以Almaraz压水堆核电厂装载的燃料组件和首循环堆芯为对象,研究了不同燃耗下有效增殖因子、动力学参数、核素浓度和双群均匀化宏观截面等组件计算结果,以及堆芯功率分布等堆芯计算结果的不确定度。分析结果表明:组件计算结果不确定度多随燃耗变化,快群宏观截面不确定度总体高于热群;堆芯计算结果受核数据不确定性影响显著,其中稳态径向功率分布的最大不确定度为1.9%左右。     

胺基功能化的炭材料上二氧化碳吸附的密度泛函理论研究

本文利用色散作用校正的密度泛函理论研究了炭材料上含氮官能团对CO₂吸附的作用。通过计算比较了不同含氮官能团炭材料结构片段吸附二氧化碳后的结构参数和能量,由于较强的静电作用和形成弱氢键,含单个苯环的酰胺和吡啶类的吸附剂吸附二氧化碳的作用强于单个苯胺和吡咯类吸附剂。但当增加苯环数时,色散作用主导的吡咯型吸附剂的吸附能力显著增强。以上结果预示着酰胺和吡咯类将是大π体系中具有良好CO₂吸附性能的吸附剂。因而,色散作用在CO₂吸附过程中也占据着重要地位。计算得到的结果与我们之前的实验结果一致,并且将有利于筛选更有效的二氧化碳吸附剂。     

二维层状分子筛前驱体的合成、改性及催化应用

二维层状分子筛前驱体具有三维分子筛的层结构单元,具备母体分子筛的特性,其开放二维片层骨架结构给合成新分子筛以及基于其改性得到新衍生结构分子筛提供新机遇,是近年来分子筛研究领域一个新热点。大量二维片层前驱体可直接合成或通过三维分子筛后处理获得,基于二维片层前驱体人们发展了溶胀、剥层、柱撑、原子扩孔、层重组等层操纵的策略,通过这些策略一些常规方法难以合成或不符合理论规则的分子筛被合成出来,这极大地丰富了二维层状分子筛前驱体的研究领域,扩展了其应用范围。本文概述了二维层状分子筛前驱体的结构特点,系统总结了近年来二维层状分子筛前驱体的合成方法,在此基础上着重阐述了其改性获得新结构分子筛的新策略,并介绍了在多相催化反应中的应用。     

新型“NH-叔丁亚砜-烯”配体的合成及其在转移氢化反应中的应用

邻叔丁基亚砜苄胺与2-乙烯基苯甲醛(或2-苯乙烯-苯甲醛)经缩合反应制得亚胺,再经硼氢化钠还原合成了两个新型的NH-叔丁亚砜-烯类三齿柔性配体(4a和4b),其结构经1H NMR,13C NMR和HR-MS表征。考察了4a或4b与Ir的络合物催化苯乙酮的转移氢化反应,转化率分别为94%和51%。     

Stochastic resonance in an over-damped linear oscillator

For an over-damped linear system subjected to both parametric excitation of colored noise and external excitation of periodically modulated noise, and in the case that the cross-correlation intensity between noises is a time-periodic function,we study the stochastic resonance(SR) in this paper. Using the Shapiro–Loginov formula, we acquire the exact expressions of the first-order and the second-order moments. By the stochastic averaging method, we obtain the analytical expression of the output signal-to-noise ratio(SNR). Meanwhile, we discuss the evolutions of the SNR with the signal frequency, noise intensity, correlation rate of noise, time period, and modulation frequency. We find a new bona fide SR. The evolution of the SNR with the signal frequency presents periodic oscillation, which is not observed in a conventional linear system. We obtain the conventional SR of the SNR with the noise intensity and the correlation rate of noise. We also obtain the SR in a wide sense, in which the evolution of the SNR with time period modulation frequency presents periodic oscillation. We find that the time-periodic modulation of the cross-correlation intensity between noises diversifies the stochastic resonance phenomena and makes this system possess richer dynamic behaviors.     

Nano-Crystalline Diamond Films with Pineapple-Like Morphology Grown by the DC Arcjet vapor Deposition Method

A nano-crystlline diamond film is grown by the dc arcjet chemical vapor deposition method. The film is characterized by scanning electron microscopy, high-resolution transmission electron microscopy （HRTEM）, x-ray diffraction （XRD） and Ftaman spectra, respectively. The nanocrystalline grains are averagely with 80hm in the size measured by XRD, and further proven by Raman and HRTEM. The observed novel morphology of the growth surface, pineapple-like morphology, is constructed by cubo-octahedral growth zones with a smooth faceted top surface and coarse side surfaces. The as-grown film possesses （100） dominant surface containing a little amorphous sp2 component, which is far different from the nano-crystalline film with the usual cauliflower-like morphology.     

现代新型测试总线技术综述

AXIe是一种针对模块化测试设备的开放式标准,继承了AdvancedTCA模块化标准架构的优点,参考了VXI、PXI、LXI和IVI等现有标准,提供了一种长寿命周期、模块化、高性能、强扩展性的柔性平台;详细介绍了AXIe1.0基础体系结构及关键技术,AXIe2.0软件标准框架,以及AXIe3.1半导体测试扩展技术及其特点,并对AXIe总线的现状和发展趋势进行展望。     

线性过阻尼分数阶Langevin方程的共振行为

通过将广义Langevin方程中的系统内噪声建模为分数阶高斯噪声,推导出分数阶Langevin方程, 其分数阶导数项阶数由系统内噪声的Hurst指数所确定.讨论了处于强噪声环境下的线性过阻尼分数阶 Langevin方程在周期信号激励下的共振行为,利用Shapiro-Loginov公式和Laplace变换, 推导了系统响应的一、二阶稳态矩和稳态响应振幅、方差的解析表达式.分析表明,适当参数下, 系统稳态响应振幅和方差随噪声的某些特征参数、周期激励信号的频率及系统部分参数的变化出现了 广义的随机共振现象.