CCD对高空间分辨率波前干涉检测的影响

推导并用实验验证了光强与入射波前在单位像元面积里成近似线性关系,从而得到入射波前经CCD采样后的功率谱密度（PSD）公式.根据该公式,模拟分析了影响CCD采集系统的系统传递函数的各个因素：入射波前、CCD的填充因子及CCD的曝光时间,得出了他们与系统传递函数的定性关系,并且通过实验明确CCD曝光时间对高空间分辨率波前检测不确定度的影响,为高空间分辨率干涉设计提供了理论依据.     

流-固界面波的激光激发与光偏转检测

基于光偏转原理,研制了可用于流-固界面波探测的光纤传感装置.在此基础上,建立了以调Q Nd∶YAG激光为流-固界面波激发光源的实验系统.实验上探测了激光在空气-铝、水-铝和酒精-铝等界面上激发的界面波波形.根据实验波形,算得在这三种界面上的泄漏Rayleigh波和Scholte波的速度分别为2889 m/s和339 m/s、2916 m/s和1512 m/s、2872 m/s和1184 m/s,此实验值与理论计算值相比,偏差小于5％.     

一种利用电光效应测量微小转角的新方法

利用线性电光效应发展出一种新的、高准确度的微小转角测量法.根据W.L. She等人提出的线性电光效应耦合波理论,求得出射光强与入射光强比值（即出射率）对入射光方向的依赖曲线,利用该曲线,通过测量出射率可以确定入射光的方向.并根据此原理,设计了一套简单的装置,该装置可以测量出物体微小转角的变化量,同时测量范围及准确度都可通过外加电场和入射光波长加以调节.对此微小转角测量法作了理论分析,在LiNbO3器件上,得到测量范围大于3′,准确度为3.5″的设计结果.     

Kinetic theory of anionic copolymerization with constant monomer ratio, 2 . Molecular weight distribution

The kinetic differential equations for the anionic copolymerization with constant monomer ratio are treated by Laplace transformation and a graphical technique. A theoretical method is established by which all molecular parameters of the copolymers, such as the molecular distribution (MWD), the average molecular weight and the polydispersity, can be calculated from reaction rate constants, initial conditions and polymerization time. Three-dimensional plots obtained by numerical computation are presented to illustrate the influence of the reaction conditions on the MWD's of the copolymers.     

Production of COx-Free Hydrogen and Few-Layer Graphene Nanoplatelets by Catalytic Decomposition of Methane over Ni-Lignin-Derived Nanoparticles

Nickel (Ni)-lignin nanocomposites were synthesized from nickel nitrate and kraft lignin then catalytically graphitized to few-layer graphene-encapsulated nickel nanoparticles (Ni@G). Ni@G nanoparticles were used for catalytic decomposition of methane (CDM) to produce COx-free hydrogen and graphene nanoplatelets. Ni@G showed high catalytic activity for methane decomposition at temperatures of 800 to 900 °C and exhibited long-term stability of 600 min time-on-stream (TOS) without apparent deactivation. The catalytic stability may be attributed to the nickel dispersion in the Ni@G sample. During the CDM reaction process, graphene shells over Ni@G nanoparticles were cracked and peeled off the nickel cores at high temperature. Both the exposed nickel nanoparticles and the cracked graphene shells may participate the CDM reaction, making Ni@G samples highly active for CDM reaction. The vacancy defects and edges in the cracked graphene shells serve as the active sites for methane decomposition. The edges are continuously regenerated by methane molecules through CDM reaction.     

Ag@CH3NH3PbI3等离激元效应增强钙钛矿太阳能电池性能的数值研究

由于银纳米粒子结构的表面等离激元共振特性对有机无机卤化物钙钛矿的新型太阳能电池性能有一定影响,利用comsol mutiphysics多物理场仿真软件对Ag@CH3 NH3 PbI3纳米粒子等离激元效应增强钙钛矿太阳能薄膜电池性能进行研究,对粒子半径和粒子间距对于能量的影响进行了计算;对光敏层能量增强的机理进行了解释;并对电场分布进行了详细说明.依据实验数据,给出优化后的银纳米粒子阵列和钙钛矿光敏层的厚度以及强度,为实验制备高效稳定的钙钛矿太阳能电池提供理论指导.     

一种基于自适应单元删除率的BESO方法

在ESO中采用动态删除率能有效地提高优化效率和稳定性,但现有的动态删除率策略都含有经验参数,确定删除率的过程较为复杂。本文提出了一种用于BESO的无经验参数自适应单元删除率确定方法。通过分析单元删除率对优化稳定性的影响,得到了结构优化过程中单元删除率的理想变化规律和单元灵敏度均匀化信息对删除率的影响情况,并据此分析了经验参数引入的原因,从而构造了评价单迭代步的单元灵敏度均匀化程度指标。然后,基于单迭代步的单元灵敏度均匀化程度指标,构造了全部迭代步信息下的单元灵敏度均匀化程度相对指标,结合单元删除率的推荐范围值,给出了一种自适应于结构优化进程的单元删除率自适应函数。最后,给出了基于自适应单元删除率的BESO方法实现流程。经典算例的结果对比说明,本文方法在保证优化质量相近的情况下,具有更好的优化效率和稳定性。     

时滞Rucklidge系统Hopf分岔分析与电路实现

以一类新的单时滞Rucklidge系统为分析对象,通过计算时滞系统的平衡点,分析该系统在各平衡点的稳定性和Hopf分岔的存在性,得到其发生Hopf分岔的条件。Matlab多组数值仿真验证了理论分析的正确性。基于此设计了一种可切换时滞与非时滞的混沌电路,并运用Multisim14.0进行仿真,实验结果表明,该电路可行且有效。     

一类改进最大熵方法的可调参数分析

在结构可靠性分析中,引入含可调参数的转换函数能对传统的最大熵方法进行改进,获得更高的失效概率预测精度。但是,此可调参数的最佳取值很难确定。针对这一问题,引入概率守恒方程,从功能函数转换前后所得概率密度函数出发,建立其最大熵值的变化关系,给出转换前后最大熵值之差的理论形式。通过对三种典型单调非线性转换函数开展算例研究,发现功能函数转换前后的最大熵值之差与转换函数的最佳可调参数值有关。改变可调参数值驱使最大熵值之差变化的同时,改进最大熵方法能遍历到更好的失效概率估计值。     

Structure and Processing Properties of Nine Yam (Dioscorea opposita Thunb) Starches from South China: A Comparison Study

In order to explore the processing and application potential of Chinese yam starch, nine kinds of Chinese yam starch (GY11, GY5, GY2, GXPY, LCY, SFY, MPY, SYPY, ASY) from South China were collected and characterized. The chemical composition, rheological properties, thermal properties, and in vitro starch digestion were compared, and the correlation between the structure and processing properties of these yam starches was analyzed using Pearson correlation. The results show that GY2 had the highest amylose content of 28.70%. All the yam starches were similarly elliptical, and all the yam starch gels showed pseudoplastic behavior. Yam starches showed similar pasting temperatures and resistant starch content, but SYPY showed the largest particle size (28.4 μm), SFY showed the highest setback (2712.33 cp), and LCY showed the highest peak viscosity (6145.67 cp) and breakdown (2672.33 cp). In addition, these yam starches also showed different crystal types (A-type, B-type, C-type), relative crystallinity (26.54–31.48%), the ratios of 1045/1022 cm⁻¹ (0.836–1.213), pasting properties, and rheological properties, so the yam starches have different application potentials. The rheological and pasting properties were related to the structural properties of starch, such as DI, Mw, and particle size, and were also closely related to the thermodynamic properties. The appropriate processing methods and purposes of the processed products of these yam starches can be selected according to their characteristics.