L (Q)格值模型的初等子模型

将带广义量词Q的一阶逻辑的二值弱模型推广到取值于完备弱可补格上,对有限的线性序弱可补格,讨论了关于L(Q)模型的初等子模型的一些性质,如强升和强降L－S－T定理,初等图像在初等扩充下的保持性等。     

一种深度学习网络的树木点云骨架重建方法

基于激光雷达(light detection and ranging, LiDAR)数据重建树体三维模型并精准获取林木空间枝干结构参数是精准林业发展的必然趋势。本文研究面向激光点云提出了一种融合基于晶格投影的深度学习网络,以及面向提取的枝干点云的树木模型骨架重建的方法。该深度学习网络包括旋转不变性模块、晶格投影与重心插值模块,多尺度变换与卷积操作层,通过将旋转变换后的点云晶格投影到三个坐标平面上再分别重心插值获得变换系数,解决了三维点云因排列无序而造成空间卷积困难的问题。以海南多类树木为研究对象,首先,把带枝叶标签的林木点云基团带入构造的深度学习网络中训练网络参数,实现测试样本中的林木数据的枝叶分离。其次,对分类后的树木枝干点云垂直分层并空间聚类,获取每层的聚类中心点并按相邻层中心点距离最小原则实现骨架链表构造,同时采用自适应随机抽样一致(random sample consensus, RANSAC)方法来计算的圆柱体拟合半径,以重建树木的各级枝干。最后,根据中心点连通的链表结构以及角度变化最小准则自动识别树木中的主枝干和各个一级分枝。通过与实测数据比对验证表明,深度学习枝叶分类准确...     

可压Euler方程的格子Boltzmann方法:二维情形

根据微观和宏观之间的质量、动量和能量守恒原理，构建了一个可用于模拟可压流体的D2V19格子Boltzmann模型，利用Chapman—Enskog分析可从该模型推导出宏观流体力学方程-Euler方程．利用该模型对三种典型激波管进行数值模拟并与Riemann解析解进行比较和分析，发现该模型能较好的捕捉激波，精度令人满意，证明了该模型对可压流体的适用性．该模型适用于气体多方指数为任意值的系统．     

埋地输油管道两相泄漏过程的格子Boltzmann模型

埋地输油管道易发生腐蚀泄漏,同时伴随着巨大的能源损失,并且对管道周围环境造成污染。根据格子Boltzmann方法的并行运算能力强、算法简单、编程容易等特点,针对埋地输油管道两相泄漏过程中流体流动特征以及两相流体间的相互作用,建立埋地输油管道两相泄漏过程的格子Boltzmann模型,并进行格子Boltzmann算法数值计算前期准备工作,确定数值计算步骤及终止准则。     

Simulation of wind gust structure in the atmospheric boundary layer with Lattice Boltzmann Method

Cold fronts occur in northern East Asia during winter and spring.After cold frontal passage,airflow is downward and accompa-nying strong winds fluctuate significantly;this is termed wind gusts.Analysis of observation data shows that wind gust structure has coherent characteristics.This is important for entrainment of spring dust storms into the upper boundary layer,where they are transported great distances.The Lattice Boltzmann Method(LBM) is a computational fluid technique based on the Boltzmann transport equation.The LBM has been used to study complex motion such as turbulence,because it describes motion at the micro level.In this paper,Large eddy simulation is introduced in the LBM,enabling simulation of turbulent flow in the atmospheric boundary layer.The formation and development of wind gusts are simulated,and a coherent structure with a combination of wave and vortex is obtained.This explains the mechanism of soil erosion and sand entrainment by the coherent structure of wind gusts.     

基于Ritz-POD法的格构式塔架结构风致振动分析

根据自立式塔架结构脉动风荷载的空间分布形式,实现了本征特征分解(proper orthogonal decomposition,POD)和基于荷载-里兹模态分析相结合的Ritz-POD算法求解Ritz振型,并结合谐波激励法(harmonic excitation method,HEM)和荷载-响应相关法(load response correlation method,LRC)实现了塔架结构风振响应和等效静力风荷载(equivalent static wind load,ESWL)的高效分析。计算结果表明:采用40阶基于荷载-里兹振型和100阶传统自由振动振型计算的节点风振响应和等效静力风荷载结果及变化规律一致且二者吻合度高,说明较少阶Ritz振型的计算精度是能够保障的。并且较少阶Ritz振型减少了谐波激励法与荷载-响应相关法的运算工作量,提高了风致振动分析的效率。另外,本文利用大型通用有限元软件SAP2000基于MATLAB系统的应用程序接口(API)开发环境,实现了塔架结构风致动力响应和等效静力风荷载的高效分析平台,可为其他大型复杂工程的风致振动分析提供参考。     

新型节能点阵智能控制系统

以AT89C52单片机为主控芯片,将LED点阵、门禁系统和语音系统结合在一起组成一个智能点阵控制系统,该系统能够实现在人体靠近感应系统时门自动打开,同时播放迎宾致辞,并利用后台时间控制整个系统的工作时间的功能.该系统有效地解决了点阵长期工作造成寿命短、能源损耗大和功能单一等缺点,具有很好的应用前景.     

Down-conversion characteristics of Eu3+ doped M2Y2Si2O9 (M = Ba,Ca, Mg and Sr) nanomaterials for innovative solar panels

Down-conversion properties of Eu³⁺ doped M₂Y₂Si₂O₉ (M = Ba, Ca, Mg, Sr) phosphors have been investigated in detail. These phosphors were synthesized via the simple, fast and cost-effective sol-gel technique at a temperature of 950 °C. Color coordinates and emission color can be altered by the varying concentration of dopant ion in Ca₂Y₂Si₂O₉ phosphor. Optimum luminescence intensity was obtained when doping 0.03 mol of Eu³⁺ ion. Using the excitation wavelength of 395 nm, these silicates showed strong red color, pure and sharp spectral peaks in visible region due to ⁵D₀→⁷F_1-3 transitions of Eu³⁺ present in the lattice. Effect of reaction temperature on luminescence was also analyzed for these phosphors. The sharp peaks in the X-ray diffraction pattern indicated the high crystallinity of prepared phosphors. Ca₂Y₂Si₂O₉ has shown an orthorhombic crystal structure. The FTIR results confirmed the metal-oxygen vibrational modes available in the range of 400–1600 cm^?1. Transmission electron microscopy images have revealed that the variation of alkaline earth metal provided a very different crystal structure. Excellent down conversion response of these phosphor materials can provide a great significance in the application of the coming solar devices.     

On lattice consensus methods

We investigate the consensus problem for classifications of three types: partitions, dendrograms, and n-trees For partitions or dendrograms, lattice polynomials define natural consensus functions We extend these lattice methods to n-trees, introducing a general class of consensus functions that includes the intersection consensus functions in current use These lattice consensus methods have a number of desirable mathematical properties We prove that they all satisfy the Pareto Axiom For each of the three classification types, we determine which lattice consensus functions satisfy the Betweenness AxiomAuthor partially supported by a research grant from the Faculty Research Committee, Bowling State University     

独立决定和非二元性选择函数的Arrow不可能性定理

研究Arrow不可能性定理的弱化问题，将独立不相关条件(IIA)弱化为独立相关决定条件，证明在非二元性选择函数环境下对IIA弱化后Arrow不可能性定理仍然成立，并将它推广到选择函数不具有连通性的群格序决策问题。所得结论表明导致IIA弱化后，不可能性定理仍然成立的根本原因不是选择函数的连通性。