论我国城市开放空间系统的优化

城市开放空间系统优化是强化生态城市建设,进而推动城市可持续发展的重要途径。本文讨论了我国城市开放空间系统优化的重大意义,指出:城市的可持续发展强烈呼唤生态城市建设,而生态城市建设必须以城市开放空间系统的优化为支撑。解析了城市开放空间系统的空间形态结构和要素组成结构,阐明了开放空间系统的实用功能、生态功能、文化功能、景观功能和调控功能等,提出了城市开放空间系统优化的理论基础和应遵循的基本原则。在此基础上,着重论述了城市开放空间系统优化的基本对策和空间布局结构优化、圈层一体化优化、系统要素优化等主要工作内容。     

我国农村救护车资源布局优化:以河南省郸城县为例

优化农村救护车资源的配置有助于缩短急救服务的响应时间,对于维护重症伤(病)员的生命安全具有重要意义。本研究以河南省郸城县为例,将15分钟作为急救车路上所需响应时间,研究了该县当前救护车资源布局下农村居民的可达性;应用ArcGIS中的p-中位模型优化了郸城救护车布局点,并运用SPSS16中的配对样本t检验对比了优化前后郸城居民救护车服务可达性变化;应用ArcGIS中的最小覆盖面模型求解了覆盖郸城县域所需的最少救护车布局点数。研究显示,通过优化能有效提高居民的救护车资源可达性,在县域范围内布局13个左右的救护车资源能基本覆盖所有居民点。这一数量对与郸城具有相似自然社会背景的黄淮海平原县域具有借鉴意义。最后,文章还讨论了研究存在的局限。     

An Explicit Integration Scheme for Solving Dynamic Problems of Solid and Porous Media

In this article, an explicit integration scheme for dynamic finite element analysis is developed and the formulations for linear elastic solid and two-phase porous media are derived. The accuracy and stability characteristics analyses show this scheme is second-order accurate, which is the same as the Central Difference Method (CDM), and possesses a broader scope of stability within the range of normal damping ratios of media. Comparing with the CDM, this explicit scheme requires no matrix factorization even if a non diagonal damping matrix is included. Therefore, the dynamic finite element equations can be integrated economically provided that the mass matrix is diagonal. To demonstrate the validity of the present scheme, three examples are provided. First, taking a single-degree-of-freedom system as an example, the results obtained by the proposed scheme are compared with the exact solutions. Second, the dynamic responses of half-space saturated porous media, subjected to a concentrated load pulse at the surface, are analyzed. Both examples show that the results obtained by the proposed scheme agree well with the analytical solutions. Finally, the dynamic responses of a plane strain plate due to a load pulse are analyzed, respectively, by the proposed procedure and the commercial code ABAQUS (both implicit module and explicit module), and the CPU costs are compared.     

Sceattas in Anglo-Saxon Graves

ANGLO-SAXON SILVER PENNIES (sceattas) are rare as gravegoods, but their provision was a regular element of burial practice in a small minority of later 7th-century-furnished inhumations and later burials. Although the number both of coins and burials is very small, they show patterns of deposition and treatment that have both a cultural and a broader chronological significance. This sample provides a window on social and symbolic attitudes to the coinages as elements of the broader material culture of contemporary society, and constitutes important corroborating evidence that the Primary Phase issues embodied a new degree of monetisation in 7th-century England.     

基于特色产业簇群的城市群空间结构优化研究

城市群在区域经济社会发展中的作用越来越重要。阐述了产业簇群理论、层域理论、空间相互作用理论和生态学理论等城市群空间结构优化依据。深入分析了特色产业簇群视角的城市群空间结构演变过程。构建了全球、国家和区域等不同尺度的廊道组团网络化城市群空间结构优化模式。最后,作者提出了思想观念创新、市场一体化建设、城乡统筹协调发展、特色产业簇群培育等城市群空间结构优化路径等。     

中国东北地区四中心城市功能关系优化

大连、沈阳、长春、哈尔滨是中国东北地区4个大区级中心城市,在新的历史时期其城市功能定位和发展关系协调至关重要。论文认为,未来15年,沈阳的政治、文化、信息中心作用不会改变,但是,面对其他城市的快速发展和竞争,其大区"龙头"作用特别是经济核心地位会相对下降。大连会渐显其大区核心地位和"龙头"作用。长春、哈尔滨市的次级中心地位依旧,分别承担起国家汽车、光电子、现代农业基地和重型装备制造业、冰雪旅游、对俄贸易中心的功能。     

Simple Homogenization-Topology Optimization Approach for the Pushover Analysis of Masonry Walls

ABSTRACT

A topology optimized rigid triangular FE macro-model with non-linear homogenized interfaces for the pushover analysis of in plane loaded masonry is presented. The shape of the mesh and the position of the interfaces is evaluated through a topology optimization approach that detects the main compressive stress fluxes in the structure. Different values of the horizontal action are considered to derive an adaptive mesh or an optimal discretization that is suitable for multiple loads. Masonry properties are calibrated by means of a homogenization approach in the nonlinear range. To tackle elastic and inelastic deformations, interfaces are assumed to behave as elasto-plastic with softening in both tension and compression, with orthotropic behavior. The two-step procedure competes favorably with classic equivalent frame approaches because it does not require a-priori assumptions on the mesh and on the length of the rigid offsets. An example of technical relevance is discussed, relying into a multi-story masonry wall loaded up to failure.     

Spinning Yarns: The Archaeological Evidence for Hand Spinning and its Social Implications,c ad 1200–1500

THIS PAPER EXAMINES the archaeological evidence for hand spinning in medieval Britain from c 1200 to c 1500. Ceramic, stone and baked clay spindle whorls have dominated the excavated finds, but a new corpus of lead-alloy spindle whorls, recorded through the Portable Antiquities Scheme and Scottish Treasure Trove, is presented here. Analysis of the metal whorls’ distribution, manufacture, dating and decoration is provided, illuminating the wide social and economic contexts in which they were used. From memento mori of pious spinners to sexually potent objects representative of lubricious gossips, the ubiquitous spindle whorl was a universal tool that had a powerful agency. The artefacts are small finds embodying daily life but also tie into the wider national economy of the High and Late Middle Ages.     

Down at the old Ship and Ball — taverns,trade and daily life in the London Borough of Southwark

SUMMARY: Archaeological excavations in Southwark over the past 50 years have proved to be a very prolific source of evidence for the material culture of people living in this part of London from the 16th century onwards. This lecture, the fourth held by SPMA in honour of the late Geoff Egan, focuses on a remarkably rich and varied assemblage of 17th- and 18th-century artefacts excavated on a site in Tanner Street in 2012. Covering a wide spectrum of activities, occupations and levels of society, these include ceramics, glass, clay tobacco pipes, pewter, copper-alloy, wood, leather, bone and ivory, with objects as diverse as cloth seals, spoons, book mounts, wine bottles and glasses, bird feeders and a mallet for playing pall mall, and sources ranging from the English Midlands to the Far East.     

Professionalising Teaching: enhancing the status of teaching,improving the experience of learning and supporting innovation in higher education

Extant literature on professions suggests that there is a readily recognisable set of characteristics of a profession, but this is a contested issue, particularly in the area of recognising the professionalism of those who teach and support learning in higher education. In the UK, the Institute for Learning and Teaching was set up as a result of the Dearing report to recognise the experience and expertise of those working in these areas. The ILT offers a model for professionalising teaching, to which continuous professional development (CPD) is key. Geographers and those who teach related subjects are already in the vanguard of this activity.