The spatial economics of geothermal district energy in a small, low-density town: a case study of Mammoth Lakes, California

This research focuses on the spatial economics of geothermal district energy (DE) systems that distribute hot fluids through a pipeline network to multiple thermal customers. We argue here that DE is held back by uncertainty about its economic feasibility when implemented in real places. DE works best with high urban densities, but in the US the best geothermal resources are in the less-populated west. Economic geography theory suggests that the optimal size of a DE firm's service area should depend on the trade-off between the economies of scale inherent in a large service area and the greater network development costs and heat loss involved in serving a large area. The HEATMAP© software program developed by Washington State University was used to study the feasibility of numerous scenarios for a proposed DE system in Mammoth Lakes, California. Results indicate that the core area of the town is large enough, dense enough, and in close enough proximity to the resource for profitable DE development. Proposed ski village developments would increase the thermal load density and significantly enhance its ability to remain competitive with other fuels, even in pessimistic sensitivity analyses regarding geothermal heat input costs, public participation, and retro-fitting costs.     

国外化工数据编篡进展简介

介绍了美国ＤＩＰＰＲ、德国ＤＥＴＨＥＲＭ和日本ＮＩＳＴ的组织情况和编篡工作，从此得到启示，以求加速我国化工物性数据编篡工作的发展。     

亟需加快我国研究型大学高水平思想库的建设

思想库在当今社会有着非常重要的作用 ,为政府、企业团体等提供关于重大问题的决策咨询 ,是现代社会不可或缺的机构。研究型大学是一个国家高层次人才聚集的地方 ,有着丰富的信息资料和学术氛围的优势。美国的许多研究型大学都建设有思想库 ,并有着重要影响 ,而我国研究型大学中思想库的建设相对滞后。本文对美国研究型大学中思想库研究的特点进行分析 ,以期对我国的研究型大学建立思想库提供参考。     

美国3年来钽铌进口情况述评

依据英国金属网公布的2003年、2004年、2005年第1季度美国钽铌原料和制品进口统计数据．评述了美国钽铌市场的状况,着重关注了中国向美国出口钽铌的情况。     

Composite bending-dominated hollow nanolattices: A stiff,cyclable mechanical metamaterial

Manufacturing ultralight and mechanical reliable materials has been a long-time challenge. Ceramic-based mechanical metamaterials provide significant opportunities to reverse their brittle nature and unstable mechanical properties and have great potential as strong, ultralight, and ultrastiff materials. However, the failure of ceramics nanolattice and degradation of strength/modulus with decreasing density are caused by buckling of the struts and failure of the nodes within the nanolattices, especially during cyclic loading. Here, we explore a new class of 3D ceramic-based metamaterials with a high strength–density ratio, stiffness, recoverability, cyclability, and optimal scaling factor. Deformation mode of the fabricated nanolattices has been engineered through the unique material design and architecture tailoring. Bending-dominated hollow nanolattice (B-H-Lattice) structure is employed to take advantages of its flexibility, while a few nanometers of carbonized mussel-inspired bio-polymer (C-PDA) is coherently deposited on ceramics’ nanolayer to enable non-buckling struts and bendable nodes during deformation, resulting in reliable mechanical properties and outperforming the current bending-dominated lattices (B-Lattices) and carbon-based cellulose materials. Meanwhile, the structure has comparable stiffness to stretching-dominated lattices (S-Lattices) while with better cyclability and reliability. The B-H-Lattices exhibit high specific stiffness (>10⁶?Pa·kg^?1·m^?3), low-density (～30?kg/m³), buckling-free recovery at 55% strain, and stable cyclic loading behavior under up to 15% strain. As one of the B-Lattices, the modulus scaling factor reaches 1.27, which is lowest among current B-Lattices. This study suggests that non-buckling behavior and reliable nodes are the key factors that contribute to the outstanding mechanical performance of nanolattice materials. A new concept of engineering the internal deformation behavior of mechanical metamaterial is provided to optimize their mechanical properties in real service conditions.     

近期美国乙烯市场综述

综述了近期美国乙烯的供应与需求状况，回顾了近期乙烯价格走势，分析了美国乙烯市场变化的影响因素。     

基于SysML的可执行体系结构框架

目前可执行体系结构的相关研究缺乏统一的描述框架和分析设计方法.为此,结合系统建模语言(SysML)中的行为图、需求图和结构图,改进美国国防部体系结构框架的三视图体系结构,在此基础上提出一种可执行体系结构框架模型,并规范可执行开发过程.应用结果表明,该框架是可行的,能为下一步体系结构的动态仿真评估验证提供方法指导.     

赖特有机建筑与"天人合一"思想

世界著名建筑大师赖特的有机建筑始终坚持"与自然和谐共生"的设计理念,创造了无数经典之作,在世界范围内引起了很大反响,至今仍为人们所迷恋.赖特的有机建筑分成草原式住宅和美国风住宅两个阶段,这两种风格的住宅创作均体现出中国哲学的"天人合一"思想.因此,挖掘中国传统哲学的内在精神,以此来诠释赖特的有机建筑,可以更加深入地体会建筑的内在涵义,并从中吸取一些对当代建筑创作有益的精髓.     

美国国家公园规划体系评述

对美国国家公园规划体系进行了调查，介绍了美国国家公园规划发展的三个阶段，物质形态规划（Master Plan）阶段，综合行动计划（Comprehensive Action Plan）阶段和决策体系（Framework of Decision Making）阶段及每个阶段的特点，总结了美国现行国家公园规划决策体系的逻辑关系和构成要素，最后对美国国家公园规划进行了评述。