基于矿物质定量热分析的灰熔融反应动力学

利用矿物质定量热分析理论对三种典型煤样灰熔融过程进行了详细分析,借助化学反应动力学相关概念,计算了灰样熔融反应动力学参数,结果表明:灰样熔融过程呈明显的三阶段反应过程,即初始熔融阶段、矿物共熔阶段以及熔融末期;熔融初始阶段反应活化能均大于后面两个阶段,矿物共熔过程活化能较初始阶段明显下降;在理论上证明了灰熔融逐渐加剧的过程。     

A design strategy of achievable linear optics for a complex storage ring lattice

A design strategy is discussed in this paper,and it provides much convenience for effectively exploring achievable linear optics and globally investigating the flexibility of a complex lattice with superperiodicity.A matching method of fractional steps,which means separately finding the standard cell setting and the matching cell setting,is adopted to simplify the complexity of the linear beam optics design in the complex lattice.The multi-objective genetic algorithm is used to find most of all the stable linear optics,and reach a target solution after multi-generational propagation,both in the standard cell and the matching cell.A fitting algorithm with gradient information is used to restore the periodicity and symmetry of the lattice,and finely adjust the linear optics for further optimization.This design strategy is applied in the Shanghai Synchrotron Radiation Facility(SSRF)storage ring,and the results are presented.     

Tune optimization of the third generation light source storage ring based on Frequency Map Analysis

Tune optimization is necessary to optimize the nonlinearity of the third generation light source storage ring. In this paper we summarize the common strategies for choosing a tune and discuss tune op-timization. Frequency Map Analysis (FMA) is applied as a tune scanning tool to reveal information about nonlinear resonances and guide the tune optimization. The Shanghai Synchrotron Radiation Facility (SSRF) storage ring is taken as a test lattice, and the optimum solutions are presented in this paper. Moreover, the third order regular structural resonances excited by sextupoles are particularly investigated, and it is found that these resonances distort the tune shifts with amplitude and show a stop-band like the linear structural resonances.     

Impact parameter and beam energy dependence for azimuthal asymmetry of direct photons and free protons in intermediate energy heavy-ion collisions

Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we have calculated the impact parameter and beam energy dependence for azimuthal asymmetry, characterized by directed transverse flow parameter F and elliptic asymmetry coeffcient v2, of direct photons and the corresponding free protons in intermediate energy heavy-ion collisions. It is further shown the anti-correlated azimuthal asymmetry between direct photons and free protons.     

Two-Dimensional Breather Lattice Solutions and Compact-Like Discrete Breathers and Their Stability in Discrete Two-Dimensional Monatomic β-FPU Lattice

We restrict our attention to the discrete two-dimensional monatomic β-FPU lattice. We look for two- dimensional breather lattice solutions and two-dimensional compact-like discrete breathers by using trying method and analyze their stability by using Aubry＇s linearly stable theory. We obtain the conditions of existence and stability of two-dimensional breather lattice solutions and two-dimensional compact-like discrete breathers in the discrete two- dimensional monatomic β-FPU lattice.     

小波分析及其在高光谱噪声去除中的应用

为了消除高光谱遥感图像中光谱曲线的锯齿型噪声,提高利用光谱曲线进行信息提取研究时的精度,文章使用USGS(united states geological survey)光谱库中的植被光谱进行模拟,添加了信噪比为30的噪声后采用小波阈值法进行噪声去除,并利用信噪比、均方误差和光谱角三项指标以及综合评估系数η来对去噪效果进行评估,寻找出最佳的参数组合。实验表明,使用db12,db10,sym9,sym6等小波对含噪光谱进行3～7层分解,采用软阈值函数处理小波变换系数并使用Heursure阈值方案进行阈值估计,然后根据第一层小波分解的噪声水平估计进行阈值调整可以得到满意的去噪效果。不过该方法对噪声水平有一定的依赖性,针对不同噪声水平时需探索更合适的参数组合。     

Improved nonlinear optimization in the storage ring of the modern synchrotron radiation light source

In the storage ring of the third generation light sources, nonlinear optimization is an indispensable course in order to obtain ample dynamic acceptances and to reach high injection efficiency and long beam lifetime, especially in a low emittance lattice. An improved optimization algorithm based on the single resonance approach, which takes relative weight and initial Harmonic Sextupole Integral Strength （HSIS） as search variables, is discussed in this paper. Applications of the improved method in several test lattices are presented. Detailed analysis of the storage ring of the Shanghai Synchrotron Radiation Facility （SSRF） is particularly emphasized. Furthermore, cancellation of the driving terms is investigated to reveal the physical mechanism of the harmonic sextupole compensation. Sensitivity to the weight and the initial HSIS as well as dependence of the optimum solution on the convergent factor is analyzed.     

叶片开缝的离心风机流场研究

本文提出在离心叶轮轮盖与叶片之间开缝,使得叶片压力面侧的高压气体射流到吸力面侧的低速尾迹区,从而直接给叶轮内的低速流体提供能量,减弱了叶轮内由于二次流所导致的射流-尾迹结构,并可用于消除或解决部分负荷时常发生的离心叶轮积灰问题.对某离心风机整机的数值模拟表明,在设计流量和小流量情况下,叶轮开缝后使叶片表面分离区域减小,整个流道速度分布更为均匀,改善了叶轮内部流场的流动状况,提高了离心叶轮性能和整机性能.研究表明,本方法对于提高离心式流体机械性能是有效的.     

一种突出目标的多光谱遥感信息提取方法

为了突出目标在多光谱遥感图像中的信息,克服由阈值法所带来的人为误差,提出了一种突出遥感目标信息的方法。利用光谱能级匹配法提取目标在图像中的相似度,并将其作为目标信息波段加入到原始数据中去,进行波段归一化处理,以减少不同波段数据的量纲或数量级的影响,进行MNF变换并合成RGB假彩色图像。以新疆哈图地区的重点成矿岩性——凝灰质粉砂岩为例,进行重点目标突出的结果表明,信息增强后的图像颜色更加丰富,与原始假彩色合成图像相比,可以识别出更多的岩石类型,比原始图像的MNF变换划分出更多地物类型。     

三维时域有限差分法计算金纳米粒子尺寸与SERS活性的关联

通过合成一系列不同粒径(16～160 nm)的金纳米粒子.观察到120～135 nm的金纳米粒子在632.8nm波长激发下具有最高的SERS活性,这与前人报道的电磁场理论及实验的结果不同.利用三维时域有限差分法对金纳米粒子的SERS活性与其尺寸以及入射光波长的关系进行模拟计算.在632.8 nm激发线下,金纳米粒子二聚体体系在粒径为110 nm左右具有最佳增强效应,其光电场耦合最强的热点处的增强因子高达109考虑到体系的平均SERS增强因子通常会比最大值低约2个数量级,计算得到的107的增强因子与实验测量值相符.同时对目前实验上尚难以合成的大尺寸的金纳米粒子进行模拟,结果表明受多极矩和大尺寸效应的影响在粒径220 nm时又出现SERS增强另一峰值.在325 nm的紫外激发线下,计算得到的增强因子仅为102.