Multi-linear Variable Separation Approach to Solve a (2+1)-Dimensional Generalization of Nonlinear Schrödinger System

By using a Bäcklund transformation and the multi-linear variable separation approach, we find a new general solution of a (2+1)-dimensional generalization of the nonlinear Schrödinger system. The new “universal” formula is defined, and then, rich coherent structures can be found by selecting corresponding functions appropriately.     

光腔模式及光束传输的特征向量算法

发展了一种新颖的适用于光腔模式及光束传输模拟计算的特征向量法.该方法的核心是基于菲涅耳-基尔霍夫衍射积分理论构造了一种新的光腔传输矩阵,通过求解激光谐振腔的本征积分方程,即可一次求解得到表征腔镜上多个光场模式振幅及相位分布的特征向量组;而谐振腔内或腔外任意地方的光场分布,也可采用该方法进行光束传输模拟而求得.对与该方法有关的单元划分、形函数选取、误差及稳定性分析等问题进行了论述,分析表明:合适的单元划分和形函数选取有利于提高计算速度、精度和稳定性.     

Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration

Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.     

三维声场边界元法几乎奇异积分问题分析

以三维声场问题为例,提出一种准确计算高阶单元几乎奇异积分的半解析算法.首先分析高阶单元几何特征,构造近似几何量,然后应用扣除法,将奇异积分核函数分解为规则核函数与近似几何量表达的奇异核函数.规则核函数积分采用常规Gauss数值积分计算,奇异核函数积分采用半解析算法计算.给出三维声场内问题和外问题经典算例,计算了近边界点的声压,结果证明本文半解析算法的有效性和准确性.     

基于线性方程组数学分离模型建立光纤传感过程检测复方缬沙坦氢氯噻嗪片溶出度

基于线性方程组数学分离模型建立在线过程检测复方缬沙坦氢氯噻嗪片溶出度方法。分别扫描缬沙坦和氢氯噻嗪的紫外吸收光谱,两组分在最大吸收波长处完全重叠。根据朗伯比尔定律吸光度加和性原理,分别测定两组分在最大吸收波长处的吸光系数,建立线性方程组数学分离模型,采用光纤传感过程分析技术(FODT)检测缬沙坦氢氯噻嗪片的溶出度,并与HPLC法相比较。在规定的溶出介质中,两种成分同时实时测定,并且FODT累积溶出度与HPLC法相比较结果无显著性差异(p>0.05)。不同批次药物的溶出行为一致,说明制剂工艺稳定,均匀度好。溶出曲线显示缬沙坦溶出快于并高于氢氯噻嗪,且30 min时两组分的溶出度均大于80%符合美国药典规定。结果表明,应用线性方程组数学分离模型结合FODT法可实现复方缬沙坦氢氯噻嗪片中双组分溶出度的同时检测,并可提供双组分的溶出过程曲线和全部溶出数据,直观反映各组分在各溶出时段的快慢,为此药建立标准提供依据。与HPLC法单点数据相比优势明显,更有利于药品评价和抽验质量分析。     

用隆格-楞兹矢量推导玻尔公式

利用隆格一楞兹矢量这一守恒量,在经典力学的框架中推导了量子力学中的玻尔能级公式,这样可以避开复杂的积分,使求解过程大大简化.     

Comparative study of heterogeneous magnetic state above TC in La0.82Sr0.18CoO3 cobaltite and La0.83Sr0.17MnO3 manganite

The magnetic, transport and structural properties are studied for La_0.83Sr_0.17MnO₃ and La_0.82Sr_0.18CoO₃ single crystals with nearly the same doping and the metallic ground state. Their comparisons have shown that ferromagnetic clusters originate in the paramagnetic matrix below Т^?>T_C in both samples and exhibit similar properties. This suggests the possible universality of such phenomena in doped mixed-valence oxides of transition metals with the perovskite-type structure. The cluster density increases on cooling and plays an important role on the physical properties of these systems. The differences in cluster evolutions and scenarios of their insulator–metal transitions are related to different magnetic behaviors of the matrixes in these crystals that is mainly due to distinct spin states of the Mn³⁺ and Co³⁺ ions.     

一种新的参数估计方法及其在混沌信号盲分离中的应用

为了有效地估计非线性映射中的参数,本文采用一种容积准则近似该映射的加权积分函数. 基于由状态空间模型建模的参数,提出了一种新的参数估计方法. 混沌信号的盲分离是一种具有挑战性的参数估计问题.将新的参数估计方法应用在该问题上, 实现混沌信号的有效重构.仿真结果表明该算法具有较快的收敛速度和较高的数值精度, 并能有效地分离原始混沌信号.     

集成成像三维显示系统显示性能的研究进展

集成成像三维显示技术是利用透镜阵列获取和显示立体图像的一种三维显示技术。本文首先综述了集成成像三维显示系统的特点,考虑其系统性能主要受分辨率、景深和观看视场角的限制,对近年来集成成像三维显示系统在增大分辨率、景深和观看视场角方面的研究进展做了综合论述,比较分析了各种改进方法的优劣。最后,对我国集成成像三维显示技术的研究现状进行了总结,并简述了本研究小组在该领域取得的若干研究成果。     

液态Ga-In合金中的团簇分离现象

与以往试验及模拟计算方法不同,文章利用从头计算分子动力学研究了液态Ga, In及Ga-In合金的偏结构. 发现合金偏双体相关函数gGaGa(r), gInIn(r)的第一峰的位置分别与液态纯Ga和纯In的第一峰 位置接近, gGaIn(r)第一峰位置大于纯Ga和纯In第一峰位置的平均值,说明液态Ga-In合金中异类原子 呈现排斥倾向, Ga-Ga, In-In团簇更容易出现.在纯Ga, 纯In中占据最高含量的1311键对在液态合金中占主导 地位,说明Ga-Ga, In-In团簇共存于液态Ga-In合金中. Voronoi多面体分析发现,随着In含量的增加, 在Ga_100-xIn_x(30 ≤x≤qslant 50 at.% ) 区域内, Ga原子周围主配位数出现突变,由12降为10,证明Ga-Ga和In-In团簇倾向于分离.该研究结果不同于 通常的微观不均匀模型,揭示了液态Ga-In合金中团簇分离的机制.