HDPE/木粉改性复合材料的制备及其长效吸水性能研究

加入HDPE-g-MAH、CG-8831和KH-550制备HDPE/木粉改性复合材料。研究其长效吸水性,发现吸水率随时间延长先快速增加,浸水35 d后缓慢增至平衡,HDPE-g-MAH改性效果最好,其饱和吸水率仅为1.503%。利用Fick第二扩散定律拟合吸水动力学曲线,得扩散系数D的顺序:HDPE-g-MAH增容HDPE/木粉复合材料HDPE/木粉复合材料KH-550改性HDPE/木粉复合材料CG-8831改性HDPE/木粉复合材料。并证明该吸水过程符合Fick第二扩散定律,相关系数R2值达0.99以上。HDPE/木粉改性复合材料尺寸变化系数CDCWCT。     

Vertical dynamic interactions of poroelastic soils and embedded piles considering the effects of pile-soil radial deformations

The paper presents an analytical solution for the vertical dynamic interaction analysis of a poroelastic soil layer and an embedded pile with the consideration of pile-soil radial deformations. The soil is treated a three-dimensional porous continuum and described by the Boer’s poroelastic model, while the pile is treated as a two-dimensional rod with both radial and vertical deformations of which the equation of motion is derived by the Hamilton’s variational principle. Without the introduction of potential functions, first take the volumetric strain of soil skeleton and pore fluid pressure as intermediate variables to deal with the equations of motion for the soil and then use the separation of variables to solve the equations of motion for the soil and the pile. By imposing the boundary and continuity conditions of the pile-soil system, the dynamic impedance in frequency domain and the velocity response in time domain of the pile top are obtained. The present solution is then verified by comparing with the corresponding finite element model computation results and the existing solutions. The effects of the pile-soil parameters on the dynamic characteristic of the pile-soil system are also analyzed. Some significant conclusions are drawn, which can provide useful reference for related engineering practice.     

冒险游戏场的起源、实例与启示

游戏是儿童成长中不可或缺的部分,儿童友好城市的重要硬件措施是建设儿童游戏据点。冒险游戏场作为代表性场所,在治愈儿童心理问题、培养儿童责任感、激发儿童危机意识和自我保护技能等方面发挥了重要作用。冒险游戏场在国外已有70余年的实践历史,但我国对冒险游戏场的研究尚处于初级阶段,在实践方面仍属空白。本文从剖析冒险游戏场的起源与核心思想入手,重点围绕欧美和日本的发展背景,对其发展历史进行系统梳理,再深入解读"常设"和"非常设"的三个典型案例,总结出设计理念"自由化"、空间要素"自然化"、场所运营"专业化"三个关键启示,为我国儿童公共空间的研究提供借鉴和参考。     

“带地进城”:农业转移人口渐进式市民化对策

落实农业转移人口市民化是构建和谐社会与推进新型城镇化的重要抓手,本文通过对市民化途径的分析研究,认为渐进式市民化是当前实现农业转移人口市民化的有效途径.同时,梳理实施市民化过程中的受阻原因,结合新型城镇化关于“人的城镇化”的发展要求,提出“带地进城”的过渡性发展对策,并分析该对策所具有的优势,着力解决农业现代化与新型城镇化同步发展、农业转移人口落户制度建设、基本公共服务设施建设等问题,以期实现农业转移人口既好又快的渐进式市民化转型.     

地形探测器接地压力对铣刨机切深精度影响的ANFIS预测

基于自适应神经网络模糊推理系统(ANFIS),利用铣刨机切深精度测定试验获得的样本数据,建立了地形探测器限深轮接地压力、铣刨深度与铣刨机切深精度之间的映射关系,并进行了验证试验,结果表明了该预测方法的有效性,同时,也为不同铣刨深度下限深轮接地压力的选择提供了依据。     

核电站DEG制冷机冷媒泄漏分析处理及防止

制冷机换热铜管的蚁穴腐蚀问题在近年来为人们逐渐认识,但国内相关的案例较少,本文通过对某核电站DEG制冷机发生的冷媒泄漏原因调查、铜管腐蚀机理分析,找出了导致铜管腐蚀的来源,根据分析的结果,给出了处理方案,最后,根据蚁穴腐蚀的分析结论,提出了防止蚁穴腐蚀发生的对策。     

教学生命周期视角下课程质量生态环境构建

按照课程启动、质量计划、质量保证、质量控制、课程结束的教学生命周期,建立教学共同体责任矩阵,构建课程质量生态环境,对课程质量施以保证服务。课程启动沿用迈阿密大学课程教学过程规划模式,说明和定义课程的需求,将布卢姆教育目标分类法运用于识别课程目标,围绕教学目标开展教学活动和学习过程评价,提供课程质量计划,采用价值链分析法了解教学行为的“增值”和“贬值”,评估教学行为对教学价值的贡献。在课程质量控制阶段,制定多元化评价模式和实践策略,通过“促进学习的评价”和“做为学习的评价”两种形成性评价关注学生的学习过程。在课程结束时,通过师师反馈、师生反馈及第三方反馈进行课程质量改进。将学习投入作为衡量课程质量的重要因素,数据分析表明,学生在课程满意度和学习绩效等方面具有较高认同度。     

‘Resistance was futile!’ Cycling’s discourses of resistance to UK automobile modernism 1950–1970

This paper investigates the place of utility cycling (cycling as a means of transport rather than as a sport or leisure activity) under urban modernism in the UK. In many western contexts the dominant feature of urban modernism was its emphasis on accommodating private vehicles to the neglect of other forms of mobility. The result was the production of a ‘car-system’ with significant change to urban and rural environments. This paper assesses resistance to what we term ‘automobile modernism’ during the high watermark of its planning and implementation (1950–1970), using the UK Cyclists’ Touring Club (now known as Cycling UK) archive. We make three contributions. First, and primarily, we highlight how cycling advocacy contested automobile modernism’s claim that cycling was ‘outmoded’. In so doing we note significant continuity in policy debates and political advocacy regarding cycling’s place in the road environment around issues such as segregation from motor vehicles. Contemporary attempts to promote cycling, as well as a wider urban sustainability agenda, are heavily influenced by this history. Second, we highlight a commonality between cycling and other resistance to automobile modernism in terms of rural and urban landscape impacts. Third, we highlight how the CTC ‘professionalized’ its advocacy to resist automobile modernism.     

Using discussion logic in analyzing online group discussions: A text mining approach

We propose a Discussion Logic-based Text Analytics (DiLTA) framework, which combines theories developed in social science and text mining fields. The framework extracts features that uncover discussion logic and uses these features in analyzing online discussions. A series of models are proposed including conversation disentanglement, coherence analysis, and visualization. Validation experiments showed that DiLTA achieved significantly superior performance over existing text analytics methods in reconstructing internal structure. A case study using DiLTA-enabled visualization on a healthcare forum illustrates the great potential of DiLTA in assisting comprehension of the internal linkage, structure, and logic of online group discussions.     

Charles Marville and the Landscapes of the Carrières d’Amérique

Charles Marville’s photographs of Paris preserve the look of streets slated for demolition under Georges-Eugène Haussmann. This article examines his photographs of the Carrières d’Amérique, or America Quarries – gypsum quarries in the outlying Parisian neighbourhood of Belleville. At a time when the rezoning of districts that were formerly extra muros was still controversial, Belleville was seen as a crime-ridden area. Marville’s photographs become documents that refute contemporary narratives of criminality. Borrowing Walter Benjamin’s view that the city ‘opens up’ to the flâneur ‘as a landscape’, the article analyses Marville’s landscapes of the Carrières d’Amérique as images that juxtapose the city, the work site, and the no-man’s land or terrains vagues at Paris’s outer limits.