芯片-系统电磁脉冲耦合的高性能全波电磁模拟

目的是研究高性能的电磁场仿真软件,对真实的芯片-系统电磁脉冲耦合过程进行高分辨率、高置信度的电磁仿真。研究重点是针对多尺度问题,突破算法的并行计算瓶颈。基于自主软件平台快速研发出仿真软件,在高性能计算平台上完成对真实复杂问题的全波电磁仿真。通过对某真实机箱内部芯片的电磁脉冲耦合仿真分析,验证了本文提出的算法的高性能、高效率的特性。     

A subspace expanding technique for global zero finding of multi-degree-of-freedom nonlinear systems

A subspace expanding technique(SET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains, which are called cells. The covering set of the cells is identified by parallel calculations with the root bracketing method. The covering set can be found first in a low-dimensional subspace, and then gradually extended to higher dimensional spaces with the introduction of more equations and variables into the calculations. The results show that the proposed SET is highlyefficient for finding zeros in high-dimensional spaces. The subdivision technique of the cell mapping method is further used to refine the covering set, and the obtained numerical results of zeros are accurate. Three examples are further carried out to verify the applicability of the proposed method, and very good results are achieved. It is believed that the proposed method will significantly enhance the ability to study the stability, bifurcation,and optimization problems in complex MDOF nonlinear dynamic systems.     

Variational quantum eigensolvers by variance minimization

The original variational quantum eigensolver (VQE) typically minimizes energy with hybrid quantum-classical optimization that aims to find the ground state. Here, we propose a VQE based on minimizing energy variance and call it the variance-VQE, which treats the ground state and excited states on the same footing, since an arbitrary eigenstate for a Hamiltonian should have zero energy variance. We demonstrate the properties of the variance-VQE for solving a set of excited states in quantum chemistry problems. Remarkably, we show that optimization of a combination of energy and variance may be more efficient to find low-energy excited states than those of minimizing energy or variance alone. We further reveal that the optimization can be boosted with stochastic gradient descent by Hamiltonian sampling, which uses only a few terms of the Hamiltonian and thus significantly reduces the quantum resource for evaluating variance and its gradients.     

固态燃料小型FAE装置空中爆炸场效应分析

通过一次引爆固态复合粉尘燃料小型FAE装置与等质量TNT在自由空间的爆炸对比实验,获得了不同距离的峰值超压值,并运用粉尘爆炸下极限浓度对云雾爆轰区半径进行了估算。结果表明,固态燃料小型FAE装置空爆峰值超压分布规律不同于TNT,云雾爆轰区内的峰值超压不呈现单调减的特征,而是在有限范围内呈现波动趋势;云雾爆轰区外的峰值超压随距离增大迅速衰减,但固态燃料小型FAE装置的峰值超压大于相同距离处等质量的TNT。高速摄影观测结果显示,固态燃料小型FAE装置爆炸的化学反应持续时间大于等质量TNT。     

Arsenic speciation and other parameters of surface and ground water samples of Jamshoro,Pakistan

This study evaluated and interpreted complex data sets of water samples collected from different sampling origins of ground water (hand pump and tube well) and surface water (municipal, river and canal). The aim was to provide information concerning the apportionment of pollution sources to obtain better information about water quality and possible distribution of As with respect to its speciation. The As (III) formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, while total iAs in water samples was adsorbed on titanium dioxide (TiO₂) and determined by electrothermal atomic absorption spectrometry. The accuracy of the proposed methodologies was confirmed by standard addition method. The recoveries of As (III) and total inorganic arsenic (iAs) were found to be >98%. The results revealed that the ground water of the area under study was more contaminated as compared to surface water samples. The mean concentration of As (III) and As (V) in the surface water samples was found to be 15.8 and 6.00?µg?L^?1, respectively, whereas, in the case of ground water samples, the contents of As (III) and As (V) ranged from 6.20 to 51.0 and 6.40 to 53.0?µg?L^?1, respectively. Principal component analysis performed on a combined (tube well and hand pump) samples data set extracted two significant factors explaining more than 60% of total variance, which suggested that the contamination sources might be natural or anthropogenic.     

热力藕合问题的交替算法

在极大的加热速率下,针对CV型非Fourier介质,提出一个热力耦合问题的解耦交替计算方法,即交替地计算两个解除了耦合的问题,逐步地得到足够精度的解。这两个问题分别是已知温度时空分布的热Hooke介质的应力分析问题和已知位移、应变和应力时空分布的非Fourier介质的热传导问题。这个方法也适用于Fourier介质,与每一解耦问题实施计算的方法无关。用简例说明了随交替计算次数的增加,其结果趋近于准确解;同时给出了对Fourier介质板一个瞬态问题的应用例子。     

软运筹学研究的回顾与展望

软运筹学处理是“议题”的一种软科学方法，是传统运筹学的一个新发展，柔性运筹学是软运筹学发展的初级阶段。软运筹学的发展趋势是更多地采用“物理——事理——人理方法论”；更多地采用“还原论与整体论”相结合的研究手段、更多地采用模糊数学方法、更多地采用“人机结合、以人为主”的技术路线、更多地采用“软计算”。     

光学向量-矩阵乘法器教学演示实验

为了在光计算教学中提供让学生更易于形象理解光的并行计算能力和实现方式的教学环境,基于向量-矩阵乘法的基本原理,采用LED阵列、光敏管阵列、柱面透镜、薄透镜等简易的基础光学元件搭建了4×4的光学向量-矩阵乘法器教学演示实验.该演示实验展示了并行光计算系统的基本功能实现和构成要素,有助于学生对光计算有初步的形象认识和了解,认知本课程的目的和意义,有利于激发学生对课程学习的兴趣.     

行波管多信号非线性注波互作用的网络并行计算

把网络并行计算技术应用于微波管的研究领域,提出了用于计算2.5维行波管多信号非线性注波互作用的基于TCP/IP协议的网络并行计算模型,编写了模拟行波管多信号非线性注波互作用过程的网络并行计算程序,其可在工作站和微机组成的计算机网络环境中实现并行计算。计算结果表明,该网络并行算法能够有效地减少行波管多信号非线性注波互作用的计算时间,提高工作效率。     

Al/Mg波阻抗梯度材料加强型Whipple结构超高速撞击特性研究

波阻抗梯度材料加强型Whipple结构具有优异的防护性能。本文的目的是研究Al/Mg波阻抗梯度材料加强型Whipple结构在5.0 km/s撞击速度下的超高速撞击特性,以及除具有高阻抗的迎撞击面在弹丸中产生更高的冲击压力和温升外,影响波阻抗梯度材料防护性能的主要因素。本文中提出一种由铝合金表层和镁合金基底组成的面密度等效于1.5 mm厚铝合金的新型波阻抗梯度防护屏,采用二级轻气炮在5.0 km/s的撞击速度下对Al/Mg波阻抗梯度材料加强型和铝合金Whipple结构进行了初步超高速撞击对比实验,研究了超高速撞击防护屏穿孔、碎片云和后墙损伤特性。与铝合金防护结构相比,Al/Mg防护结构具有防护屏穿孔翻边更明显、后墙损伤较轻微、碎片云扩散半角大和撞击坑细化程度高4个主要特征。本文中开展了理论分析与计算,研究了冲击耦合过程、波传播特性和热力学状态等。结果表明：不受面密度影响,Al/Mg防护屏能改变冲击波在靶中的传播特征,使弹丸破碎程度更高,并且提升了防护屏中的内能转化率,具有优异的动能耗散特性。因此,与同等面密度的铝合金Whipple结构相比,Al/Mg结构具有更优异的防护性能。