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.     

再论我国发展注气提高采收率技术

在我国未来的石油工业中，提高石油采收率处于愈来愈重要的地位，这将是一项迫切而重大的战略任务。我国油田类型多，地质情况复杂，应该多元化地发展该项技术，尤其是我国的低渗透油藏，虽然地质储量在50×１０^８ｔ以上，但动用程度很差。现根据最近在美国、加拿大查阅的资料，再论注气技术，希望对近混相驱注气技术、注N₂推动与原油能混相的气体段塞(CO₂、富含C₂~C₆中间分子量烃等)的混相驱技术、利用注气体混合物(CO₂/C₁、CO₂/N₂、C₁/N₂等)来改善单井吞吐的增产效果技术和轻质油油藏注空气驱（低温氧化）技术等予以重视，以此促进我国注气技术的发展。     

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。     

美国对“国有企业私有化抵消补贴”的认定及我国的策略

美国商务部判断国有企业私有化抵消补贴方法经历了几次修改。1989年美国商务部认为国有企业独立交易实现的私有化将会消除过去得到的补贴;1991年美国商务部又得出相反的结论。1993年美国商务部推出了“三步法”,要求被申请人自行证明私有化过程中补贴利益的完全偿还,以证明补贴利益没有被传递。目前美国商务部运用的是“同一主体法”,即如果交易前后的实体为同一个实体,则补贴将会传递给新所有者,私有化之后的企业会获得补贴利益;反之,则不会获得补贴利益。我国的策略是坚持WTO主张的独立交易法进行认定。     

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。     

Experimental heat transfer in supercritical water flowing inside channels (survey)

This literature survey is for heat transfer to supercritical water flowing in channels. The objectives are to assess the work that was done and to understand the specifics of heat transfer at these conditions. Our exhaustive literature search, which included over 450 papers, showed that the majority of experimental data were obtained in vertical tubes, some data in horizontal tubes and just a few in other flow geometries including bundles. In general, the experiments showed that there are three heat transfer modes in fluids at supercritical pressures: (1) normal heat transfer, (2) deteriorated heat transfer with lower values of the heat transfer coefficient (HTC) and hence higher values of wall temperature within some part of a test section compared to those of normal heat transfer and (3) improved heat transfer with higher values of the HTC and hence lower values of wall temperature within some part of a test section compared to those of normal heat transfer. The deteriorated heat transfer usually appears at high heat fluxes and lower mass fluxes. Also, a peak in HTC near the critical and pseudo-critical points was recorded. Due to the limited number of publications that are devoted to heat transfer in bundles cooled with water at supercritical pressures, more work is definitely needed to provide the additional information for design purposes.     

What is the future of solar energy? Economic and policy barriers

The most important characteristics and limitations of solar energy were reviewed in this study. The analysis of different aspects indicated that the most important global challenges of solar energy development were climatic challenges, technical constraints, and unwillingness to make investments. After describing current conditions and predicting the future of solar energy, this study analyzed the policies formulated by developed countries to develop this from of energy. Accordingly, China has gotten ahead of other countries in this industry due to the technological production of solar panels and governmental supports. Finally, the economic estimation of solar energy was presented by dealing with the economic barriers to this form of energy in developed countries. According to the significant growth in the reduction of solar energy electricity production cost, this source of energy can be used as a major source in the future. It was then recommended to use a hybrid of solar energy with other sources such as wind to reduce the costs.