利用刚性体识别的三维尺寸标注完备性检查

为了实现有循环约束的尺寸完备性的自动检查,将循环约束的判断问题转化为刚性体的识别问题,提出一种基于刚性体识别的三维尺寸完备性检查方法.首先引入定位元的概念,并建立了基于恒定度求交的定位元组选择机制;然后以定位元组为基准,提出基于轨迹相交法的刚性体识别方法;再通过向刚性体内部添加虚尺寸,利用等价定位元组的固定实现了刚性体的合并;最后根据刚性体的合并状态和尺寸的使用状态,分析了尺寸的4种完备性状态.以一个有循环约束和冗余尺寸的模型为例演示了尺寸完备性的检查过程,验证了该方法的有效性和稳定性.     

基于混沌时间序列的负荷预测及其关键问题分析

通过对混沌时间序列进行分析,找出了运用它进行电力系统负荷预测的关键因素:"取舍规则"、嵌入维数和延时的选取.笔者还建立了一种"取舍规则",并运用它进行了实例分析,结果表明基于该"取舍规则"进行负荷预测的效果良好.     

Dried jujube classification using support vector machine based on fractal parameters and red,green and blue intensity

A new method that combines fractal theory and red, green and blue (RGB) colour intensity was developed to sort dried jujube fruits by using support vector machine (SVM). Our result shows that the new method is fast and accurate in dried jujube fruits classification. The SVM models based on fractal parameters only achieved 85.18–92.73% total accuracy rate. The total classification accuracy of SVM based on RGB intensity values was 94.44%. However, the SVM models based on combining fractal parameters with RGB intensity values achieved 94.44–98.15% total accuracy rate. The best classification accuracy (98.15%) was found when using SVM model based on combining fractal measures (FM) with RGB intensity values (C = 512, γ = 0.0078125). Therefore, the SVM model based on combining FMs with RGB intensity is recommended in dried jujube fruits classification.     

An empirical study of cultural dimensions and e-government development: implications of the findings and strategies

We aim to examine whether national culture has an impact on e-government development. We used methods of correlation and multiple regression to analyse two sets of index: (1) Hofstede's cultural dimension index and (2) the e-government development index of the 2010 United Nations e-government survey. We found that there is a correlation to a various degree between e-governmental development and the cultural dimensions defined by Hofstede. Of the five cultural dimensions, we found that, individualism (i.e. the extent to which an individual is integrated into a group), power distance (i.e. the extent to which a society accepts the differences and inequalities in power distribution) and long-term orientation (i.e. the extent to which a culture programs its members to accept delayed satisfaction of their material, social and emotional needs) are significantly correlated with e-government development. The implications of the findings and the strategies proposed by this study could help governments and decision makers design and implement policies that take into account cultural factors to improve e-government services and their overall development. This study confirms and supports previous research and extends the scope of, and updates the results of, similar studies in the field.     

Places that Support Human Flourishing: Lessons from Later Life

This review paper contends that by paying attention to the quality of life issues raised by older people, planners may promote better places for all. Recent research in the UK that asked older people to identify quality of life criteria revealed that health, income, social networks, community participation, information, activities, home, neighbourhood and mobility are key areas where old age can be enriched. The paper argues that of these, home, neighbourhood and mobility are paramount for four reasons. Firstly, older people are seen as situated, even fixed, in domestic environments; secondly, society has responded to later life by creating age-segregated spaces; thirdly, lessening mobility may increase the importance of the local arena and fourthly the interplay between the self and the environment underpins or undermines independence. The significance of place means that planners, even more than other professionals, need to be age aware. Drawing on recent national and international research this paper contemplates what a more age-friendly place might be like and considers how issues of age can interact with the broader planning agendas of sustainability, cohesion and liveability to create places that promote well-being for every member of the community.     

结合方式和试样尺寸对矾土基浇注料受热爆裂性能的影响

为了考察试样尺寸对浇注料受热爆裂性能的影响,研究了以低水泥、超低水泥、硅溶胶、α-bond及MgO-SiO2-H2O结合的矾土基浇注料不同坯体尺寸的抗爆裂性能及物理性能,发现试样尺寸对浇注料爆裂性能的影响与其中低温物理性能密切相关:1)坯体较密实且强度较高者,试样大小对受热爆裂性能影响较大;而初始坯体气孔较多且强度不高或初始坯体较密实而强度一般者,试样大小对受热爆裂性能影响不大。2)当试样尺寸较大时,各体系结合浇注料都较容易发生爆裂,结合方式对浇注料爆裂影响不大;而试样尺寸较小时,以水合结合试样更容易发生爆裂。     

Ageing of aluminium hydroxide flocs

The ageing processes of kaolinite suspensions flocculated with Al₂(SO₄)₃ under a variety of different but well-controlled flocculation conditions were studied by measuring their average diameter, diameter distribution, strength and electrophoretic mobility.Three periods could be distinguished in the ageing process. Initially shrinkage of the flocs is mainly due to cementation-aggregation. In the first 6–8 h, dependent on the flocculation conditions, the average diameter reduces from 500 to 220 μm. During the following 4 days a shrinkage to 180 μm occurs, mainly due to condensation-polymerization and crystallization. In the third period, the average diameter increases because of Oswald ripening of the crystals.During each period the change of the diameter as a function of age can mathematically be described by: d_f,i = d∞ + d′· t_i^+i−ω. With d_∞, d′ and ω constants dependent on the flocculation conditions.During ageing, the floc diameter distribution narrows. The shrinkage of the flocs during ageing is definitely not due to erosion of particles from the floc surface.The change of the electrophoretic mobility during ageing provides information on the thickness and homogeneity of the layer of insoluble hydroxides around the destabilized clay particles.The influence of a wide range of different flocculation process parameters on the floc ageing process is summarized, as is the influence of the ageing process on floc strength and floc density. The evolution of the effective floc density can be described by: .The constants K_p and a are functions of the ratio quantity of suspended solids vs coagulant dose.     

钢网在墙体抹灰砂浆塑性阶段抗裂性能试验研究

针对墙体抹灰砂浆上墙后易出现裂缝的工程现状,选择了几种典型的镀锌钢网,通过加速试验手段进行抹灰砂浆抗裂性能试验,比较和分析了不同规格钢网抵抗砂浆塑性阶段裂缝效果的差异,为合理选用墙体防裂钢网提供了有益的数据和资料。     

中国“城乡一体化”进程中园林规划领域运用“五维理论”的探索研究

中国"城乡一体化"的规划与建设,不能盲目化、西化,要有自己的特色,要有适应中国本土的园林规划理论和方法。风景园林师就像一个大地医生,要去给大地号脉,"五维理论"就像中医中的"人体经络理论"一样,研究环境的一种内在气息、内在本质。运用"五维空间"园林设计理念就是:园林设计应以"三维空间"为基础,安排其在第四维(时间轴)上进行表现,并在第五维(能量场)上调整合理,最终达到整体和谐的景致效果。通俗地讲就是,园林设计不仅要研究可见、有形的景观因素,还要研究不可见、无形的景观因素。     

岩爆实验碎屑分类及其研究方法

 利用中国矿业大学(北京)岩爆过程模拟实验系统,进行一系列的应变岩爆实验。对岩爆碎屑不同尺度,可以采用不同方法提取其信息,包括对面积约为100 mm2的中粒碎屑SEM(扫描电子显微镜)扫描,粗粒碎屑的断口表面形貌三维激光扫描和岩爆碎屑颗粒的尺寸特征测量。测量参数为质量、长度、宽度和厚度。为了便于对不同尺度的岩爆碎屑进行研究的方便,将岩爆碎屑分为粗粒、中粒、细粒和微粒4组,对不同粒组采用不同的研究方法。以花岗岩为例,介绍不同方法计算分形维数的过程及结果。采用倍分长度区间、SEM裂纹图像处理的二值法及小岛法进形分形维数计算时,其线性关系都较好,但不同方法计算获得的分维值不同。根据不同粒组的分形结果,可以分析不同尺度下的岩爆碎屑破碎程度,并为进一步研究岩爆过程的能量变化特征提供基础。