数学物理方程的MATLAB数值解法与可视化

选取数学物理方程及其初、边值问题的差分格式,使用有限差分法,利用M atlab得出其图形解;直接利用M at-lab的PDE工具箱,借助图形用户界面得到数学物理方程的图形解;对结果进行了分析总结.     

基于认知风格的Web目录检索界面实证分析

提出基于认知风格模型的检索界面设计原则,以搜索引擎Google作为实验对象,基于认知风格理论,从界面整体风格、主目录和子目录排列方式、命中网站的排序方式、检索结果的表示方式及相关目录显示5个方面分析Google检索界面并提出相应的优化策略。     

电子商务网站的用户隐喻认知初探

利用人们的隐喻认知现象,探索网站界面信息组织中的隐喻应用,对于促进用户理解界面信息具有积极意义。在梳理有关隐喻概念及其有关隐喻认知机理基础上,实验探索网络用户学习抽象概念时认知隐喻的影响作用,并对现有网络界面中的隐喻要素进行用户评价,从而为隐喻化界面构建提供理论依据。     

Individualization of data-segment-related parameters for improvement of EEG signal classification in brain-computer interface

In electroencephalogram (EEG) modeling techniques, data segment selection is the first and still an important step. The influence of a set of data-segment-related parameters on feature extraction and classification in an EEG-based brain-computer interface (BCI) was studied. An auto search algorithm was developed to study four datasegment-related parameters in each trial of 12 subjects’ EEG. The length of data segment (LDS), the start position of data (SPD) segment, AR order, and number of trials (NT) were used to build the model. The study showed that, compared with the classification ratio (CR) without parameter selection, the CR was increased by 20% to 30% with proper selection of these data-segment-related parameters, and the optimum parameter values were subject-dependent. This suggests that the data-segment-related parameters should be individualized when building models for BCI.     

一种新的径向导热界面参数插值格式

以变系数径向导热问题为研究对象,由傅里叶导热定律提出了较之文献更为合理的热导计算方法.根据流的相容性原理分别推导得出极坐标、柱坐标和球坐标系下新的界面半径和界面导热系数插值格式.通过几个变系数和非线性导热问题对插值格式进行考核,并与文献中的插值格式进行对比.结果表明,推导的格式充分考虑了变截面和变物性的综合影响,对于非线性和变系数导热问题能得到更精确的结果.     

倾斜界面绕射波时距曲线特征及其应用

根据几何地震学原理推导了倾斜界面情况下的绕射波时距曲线方程,采用2种方法证明倾斜界面反射波与绕射波交点位置解的存在性及其唯一性.理论分析表明,倾斜界面绕射波时距曲线仍具有双曲线特征,且最小旅行时点的位置始终在绕射点正上方,与地层倾角等因素无关,是水平界面情况的一般形式.定性和定量研究了交点坐标趋向于无穷大时的临界参数计算公式,数值实例验证了这一结论.采用实际地震资料指出了常规地震容易导致的解释误区.     

Pd/CeO2催化CO氧化活性对载体CeO2形貌的依赖效应

Pd纳米颗粒的氧化还原性能对Pd/CeO₂催化氧化反应的性能至关重要,且与Pd-CeO₂的界面结构密切相关.我们发现Pd/CeO₂的低温催化CO氧化活性高度依赖于载体CeO₂的形貌和暴露晶面.利用胶体沉积法,得到Pd/CeO₂八面体和Pd/CeO₂立方块两种催化剂.结果表明暴露{111}晶面的CeO₂八面体负载Pd催化剂的催化CO氧化活性远优于暴露{100}晶面的CeO₂立方块负载Pd催化剂.DFT理论模拟计算结果表明,催化剂表面的Pd物种的氧化还原活性可能决定催化剂的可还原性和催化活性:钯从氧化态到金属态的循环更容易在CeO₂(111)上进行,而这取决于Pd与载体CeO₂之间的相互作用.我们的结果表明,催化剂表面活性Pd物种的氧化还原性能对Pd/CeO₂的催化活性至关重要,可以通过调控载体暴露的晶面实现Pd与载体CeO₂之间的相互作用,最终实现对催化剂可还原性和催化活性的可控调变.     

智能环境关键技术研究

智能环境是信息技术为人类服务提供的一种新概念和新技术,它帮助人们更加有效地工作,提高人们的生活质量.介绍了智能环境的概念及应用,讨论了智能环境中的节点系统、通信技术、人类自然感觉界面、可信任和安全等关键技术.     

论网页与界面设计中艺术的运用

随着时代的发展．网站建设越来越接近于一门艺术而不仅仅是一项技术。网页的艺术设计,日益被网站建设者所注重。在目前国内对此领域研究甚少的情况下,作者将网页艺术设计与其他艺术设计形式进行比较,尝试从网页艺术设计的内容、原则和特点三个方面,对这个新的艺术设计领域进行初步的归纳总结和理论探讨。作者认为网页艺术设计是艺术与技术的高度统一。网页艺术设计包含视听元素与版式设计两项内容：以主题鲜明、形式与内容相统一、强调整体为设计原则;具有交互性与持续性、多维性、综合性、版式的不可控性、艺术与技术结合的紧密性五个特点。明确了“美”和“功能”都是为了更好地表达网站主题这一观点。     

Theoretical and experimental studies of heat transfer with moving phase-change interface in freezing and thawing of porous potting soil

Soil in a cold region is subject to frequent freezing and thawing cycles. Soil frozen for a prolonged period may cause adverse freeze damage to the plants due to cell dehydration or root cell rupture. It is important to understand the detailed heat transfer behaviors of the freezing and thawing processes to prevent freeze damage, and to devise proper mitigation measures for effective pot planting in cold regions. A theoretical model was developed to analyze the transient moving phase-change interface heat transfer in the freezing and thawing of porous potting soil. The theoretical derivation is based on the assumption that the soil freezes completely at a single temperature. Microscopic poromechanic effects on heat transfer behavior were ignored. The spatial domain of the problem was simplified to a 1 D spherical coordinate system with variation in the radial direction. Green＇s function was applied to solve for the time-dependent body temperature. Experiments were conducted for validation of the theoretical model Reasonable agreement between the theoretical predictions and experimental measurements was obtained. The theoretical model developed can be easily used to determine the sensitivity of various parameters in the freezing/thawing processes, e.g., thermal properties of soil, ambient temperature, and planting pot size.