Al-20%Cu多晶粒竞争生长的原位观测及汇聚型枝晶淘汰模型构建

采用同步辐射成像技术研究Al-20%Cu(质量分数)亚共晶合金的晶粒竞争生长动力学,并建立与实验结果相一致的数学模型。结果表明,对于发散型竞争生长,遵循“正常淘汰”规则。对于汇聚型竞争生长,成分过冷的作用加速非择优取向晶粒中一次枝晶臂的生长速度,导致非择优取向枝晶出现“异常淘汰”现象,淘汰择优取向枝晶。探讨汇聚型竞争生长的“正常淘汰”与“异常淘汰”之间的临界条件,建立枝晶生长速率、枝晶臂间距和枝晶倾斜角之间的数学关系,又称“二次枝晶臂阻挡模型”,可以快速预测晶界位相和淘汰类型。

Influences of Used Parameters of Screw Distributor upon Mixture Paving Segregation

The paving segregation of asphalt mixture was closely related to the structure size and using parameters for the screw distributor of paver,and the paving uniformity of the mixture was determined by the screw blade diameter,pitch,and the position of the mixture in the screw distributor.Through researching the kinematics of the mixture in the screw distributor,the mathematical model was established,and the mathematical model was related with structural parameters,used parameters and material parameters.Through the mathematical model,the various parameters on the screw distributor job performance were analyzed,and the unstable area,meta-stable area and stable area were determined.In the project,the full-scale test in actual project was conducted by using the AC25 mixture.By changing the using parameters compare the paving operations,the results show that,the reasonable parameter will greatly improve the uniformity of paving,and the surface proportion of structural depth of mixture decrease from the 2.13 to 1.60.

EVOLUTIONARY DYNAMIC MODEL OF POPULATION WITH NICHE CONSTRUCTION AND ITS APPLICATION RESEARCH

Based on the theories and approaches in biomechanics, the mechanism and pattern of niche construction were discussed systematically. Through establishing the spatial pattern of niche and its measuring-fitness formula, and the dynamic system models of single- and two-population with niche construction, including corresponding theoretical analysis and numerical simulation on their evolutionary dynamics of population and the mechanism of competitive coexistence, the co-evolutionary relationship between organisms and their environments was revealed. The results indicate that population dynamics is governed by positive feedback between primary ecological factors and resource content. Niche construction generates an evolutionary effect in system by influencing the fitness of population. A threshold effect exists in single population dynamic system, in dynamic system of two competitive populations, niche construction can lead to alternative competitive consequences, which may be a potential mechanism to explain the competitive coexistence of species.

Theory and Application of System Integration for Real-Time Monitoring of Core Rock-Fill Dam Filling Construction Quality

The theory and method of system integration for the real-time monitoring of core rock-fill dam filling con- struction quality are studied in this paper. First, the importance analysis of system integration factors is carried out with the analytic hierarchy process. Then, according to the analysis result of integration factors, the conceptual model of system integration is built based on function integration, index integration, technology integration and information integration, the index structure of core rock-fill dam filling construction quality control is constructed and the method of function integration and technology integration is studied. The mathematical model of process monitoring is built according to monitoring objective, process and indexes. Research results have been applied in Nuozhadu core rock-fill dam construction management, realizing system integration through building appropriate monitoring work flow and comprehensive information platform of digital dam.

Medium-term scheduling of operating states in electric power systems

This article presents a mathematical model for the medium-term scheduling of the operating states of electric power systems.The scheduling period is divided into several time intervals.The model can be used to determine the equilibrium state in which each supplier earns maximum profit from supplying electricity to the wholesale market.We estimated the maximum value of public welfare,which indicates the total financial gains of suppliers and consumers,to determine the prices at the nodes of the power system.This was done by considering the balance constraints at the nodes of the power system and constraints on the allowable values of generation,power flows,and volumes of energy resources consumed over several time intervals.This problem belongs to the class of bi-level Stackelberg game-theoretic models with several leaders.The market equilibrium is modeled simultaneously in several intervals,given the multiplicity and duration of interactions.We considered two approaches for solving the multi-interval equilibrium state problem.The first approach involved directly solving a system of joint optimality conditions for electricity suppliers and consumers.The second approach involved iterative searches until the equilibrium state was reached.This article presents the results of medium-term scheduling using a case study of a simplified real-world power system.

Study on Ground Deformation during Shield Tunnel Construction

Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the assumption of linear small deformation,a mathematical model of the relationship between ground deformation and construction parameters is set up.The principle and method of optimization for estimating ground deformation is studied.The actual measured data are compared with the results of theoretical analysis in a case.Considering different ground formations in different construction sites with different adverse effects on surface and underground structures,the ground surface deformations caused by shield tunneling is an aimed topic in this paper.The contributions and research implications are the revealed relationships between the ground deformation and the shield tunneling parameters during construction.

STEAM教育视角下中学数学建模题的研制

该文以STEAM教育为切入视角,提出了研制数学建模题的“五步构造法”,并以有相关背景的高考原题的改编为例展示了该方法的具体运用。

单T型半桥DAB变换器的工作模式分析

针对宽电压运行直流源接入直流电网的应用场景,文章提出一种基于T型三电平结构新型直流变换器,通过开关函数构造法推导该变换器在四自由度控制下的工作模式以及传输功率和电感电流均方根值的数学模型。

基于学习通教学平台的数学建模竞赛培训模式的实践与研究

文章以常州大学为例,探讨基于学习通教学平台的数学建模竞赛培训模式的实践与研究。首先分析了学习通教学平台的优势,介绍了数学建模竞赛培训的常见模式;接着提出了基于学习通教学平台的数学建模竞赛培训模式构建思路及教学内容规划,并对其教学实施进行了探讨。通过研究,旨在为数学建模竞赛培训提供一种新的教学模式,以期提高学生的数学建模竞赛能力。

艺术介入乡村建设的设计竞赛与实践模式

研究艺术介入乡村建设的设计竞赛与实践案例,探究两者价值差异与融合路径,为我国乡村建设提供经验启示。多途径收集高价值竞赛与实践案例,依据社区营造切入点,从人、文、景、地、产五方面进行分类,筛选出典型案例进行深入解构,从切入点、设计手段、资源整合等层面纵向分析设计竞赛与实践案例的路径特点,横向对比二者的异同优劣。归纳得出实践与竞赛纵向的显著规律,在两者横向对比中提炼之间差异、联系及转化融合的可能方式。对现有艺术乡建设计竞赛与实践案例的分析反思,有利于探索两者未来的融合发展方向。

高职院校数学建模竞赛资源转化的实践研究

针对数学建模竞赛跨学科、跨专业的特点,为实现优质竞赛资源的普惠化,基于数学建模竞赛进行资源转化和应用推广。通过深入剖析2010—2021年间全国大学生数学建模竞赛的相关资源和优秀成果,将其进行梳理整合,分别从竞赛资源转化为专业课程资源、高职数学实践教学资源和职业素养资源三个方面进行实践研究。利用数学建模竞赛的资源转化,填补了学科性竞赛资源转化的空白,深化了高等数学与专业课程间的赛教融合,促进了高职院校复合型职业技能人才的培养。

基于VOSviewer的测评机构市场竞争特征分析模型的构建

网络安全等级保护在网络安全保障、网络强国建设方面发挥着至关重要的作用。随着资质管理从审核推荐模式向服务认证模式的转变,网络安全等级保护测评机构的资质管理得到网络安全界越来越多的关注。在分析网络安全等级保护测评机构投标项目信息的基础上,应用VOSviewer知识图谱软件构建一种市场竞争特征分析模型,为等级测评行业的高质量发展提供参考借鉴。首先对采集数据进行清洗以及基于相似度去重;然后采用机器学习算法对项目信息进行“关键词”(项目类型、项目所属行业)的抽取和标注;最后将项目信息进行RefWorks格式转换并导入VOSviewer,可视化呈现测评机构的竞争关系和市场特征。

STEAM教育理念落地:数学文化项目学习模式构建及案例开发

STEAM教育是集科学、技术、工程、艺术和数学于一体的跨学科实践活动,正成为国内外教育理论与实践发展的潮流。STEAM教育理念是以数学为基础,通过科学和技术去解读艺术与工程,所以,基于数学的广泛应用性推广和发展STEAM教育理念尤为重要。该研究分析了目前STEAM教育理念落地数学教育的现实困境,将数学文化作为STEAM教育理念落地数学教育的突破口,首次尝试将项目学习引入数学文化教学中,构建了数学文化项目学习模式,以促进STEAM教育理念与数学教育的深度融合,是对STEAM教育实践范式的一次新探索;开发设计了“从测影计时到铜壶滴漏”数学文化项目学习典型案例,充分体现出项目学习模式在数学文化教育中具有培养学生综合素养及实践创新能力的作用。

基于AHP法的大型LNG工厂开工复产问题研究

为了研究大型LNG工厂开工复产问题及原因,以某大型LNG工厂开工复产情况为依据,结合AHP法数学建模。研究表明,使用AHP法可将模糊定性的问题汇总量化为科学权重,有效解决了因数据不足、量化标准不一而造成的分析瓶颈,降低了复产风险。该工程中三台压缩机正常启动是正常开工的关键。三机启动后要注意安全隐患的发生,同时不能延误工期影响生产。下步可针对开工难点及生产难点进行流程、设备上的改造。找出节能降耗与系统平稳共赢点。

图书馆的竞争型资源建设——以国家工程技术图书馆为例

在经典“五力模型”的基础上,根据图书馆与企业的差异性,分析图书馆资源建设中的各个关键作用力量,提出图书馆的竞争型资源建设框架,并分析该框架的具体内容。以国家工程技术图书馆的竞争型资源建设为例进行实例分析,表明图书馆竞争型资源建设行之有效。

建筑物化阶段CO_(2)减排量DEA数学建模研究

常规的数学建模方法在建筑物化阶段难以准确测算边界结构,为准确模拟CO_(2)减排量计算结果,使用DEA算法,建模分析建筑物化阶段CO_(2)减排量。获取建筑材料加工运输以及使用阶段具体减排参数,设定DEA数学模型测算边界,分别计算其时间边界与空间边界,构建DEA数学模型总体框架,计算建筑物化阶段CO_(2)减排总量,实现建筑物化阶段CO_(2)减排量的数学建模。实验结果显示,该数学模型在现场浇筑与直接装配的工程中,均能得到更准确的模拟结果,模型应用误差更小,CO_(2)减排量计算结果的准确性得到优化。

推进辽宁省A市开放式小区建设的实践调查研究

以国务院发布的《关于进一步加强城市规划建设管理工作的若干意见》为背景,调查了国内外近年来新建设的开放式小区现状,并以辽宁省A市4个典型小区为例,对小区开放后的一些问题进行了整理和总结,初步分析了开放式小区的利弊,并通过仿真软件模拟开放式小区,建立了多种因素影响下的MATLAB数学模型,定量比较了开放前及开放后的小区。根据研究结果,提出了如下建议:建设开放式小区应坚持以人为本的原则,应从法律法规、监管体系、社会环境等多方面入手,合理规划并建设社区。研究结果可为辽宁省A市开放式小区建设及管理提供参考。

《排水系统数学模型构建及应用标准》解读

为规范上海市新一轮排水规划编制、排水系统“厂、站、网”一体化运行监管平台建设、水务行业数字化转型升级等相关工作中排水模型的构建和应用,上海市住房和城乡建设管理委员会组织编制了《排水系统数学模型建立及应用标准》。文章对该地方标准的制定和基本规定、数据收集与处理、模型构建与测试、模型率定与验证、模型评价与验收、模型应用与维护等关键要点进行了解读。

“赛课一体”模式下数学建模课程群的构建与实践

数学建模与数学学科同步产生,却因数学建模竞赛而被人们熟知。全国大学生数学建模不仅是我国最具影响力的竞赛之一,也是推动我国数学教育改革的驱动力之一。文章回顾了数学建模的起源与发展,分析了数学建模课程建设中存在的问题,探索了基于“赛课一体”的数学建模教学改革模式,通过课程组建设、组织校赛、优化课程内容,将数学建模竞赛、数学建模课程建设和课程思政相融合,以赛促教、以赛促学,全面提升学生的素养和创新能力。

“三新”背景下高中数学课堂教学策略探究

“三新”(新课标、新教材、新高考)改革,对高中数学课堂教学来说,既是机遇也是挑战。为此,教师要优化教学策略,引入游戏化教学方式,实施项目式学习模式,创设数学实验室,推行数学写作,开展数学建模竞赛,以此发展学生的数学思维,提升学生的数学核心素养,打造高效数学课堂。文章基于“三新”背景,探究高中数学课堂教学的创新策略,积极推动高中数学课堂教学改革。