淬火速率对AA7108铝合金的微观结构和力学性能的影响

在480°C固溶温度对AA7108铝合金进行不同工艺的淬火。将合金连续冷却、淬火至中间温度（400,300和200°C）并保温不同时间,再进行工业两步人工时效处理,以获得最大强度（T6）。T6态淬火材料的拉伸试验表明,材料的强度很大程度上取决于冷却/保温时间。通过透射电子显微镜（TEM）观察材料中沉淀物结构来解释材料的力学性能差异。     

冬冷夏热地区利用发热电缆地板采暖的经济性分析

我国长江中下游地区是冬冷夏热地区,天然热环境差。随着人民生活水平的提高,越来越多的用户要求冬季采暖。本文根据国家节能要求,分析了该地区利用发热电缆地板采暖的经济性,论证了其可行性。     

Characteristics and Nature of Metal Fog in Molten Salts

In this paper are reported the characteristicsand nature of metal fog in molten cryolite-aluminamixtures on the basis of laboratory experiments andquantum chemistry studies.The metal fog is thefinely divided metal particles in the molten salts,and it dissolves partly in the molten cryolite to formatomic clusters,such as(Al_nNa_m)~(x+) type.     

A thermodynamic description of the Si-rich Si-Fe system

Phase equilibria in the Si-rich domain of the Si-Fe system have been reassessed based on the recent DTA experimental results.Thermodynamic properties of liquid phase have been reassessed using the associated solution model.The properties of DIAMOND A4 mixture phase have been added in order to evaluate the phase equilibria for the pure silicon materials.The assessed system is able to reproduce the experimental values in the whole composition range of the Si-Fe system.     

Explaining experience curves for new energy technologies: A case study of liquefied natural gas

Many new energy technologies seem to experience a fall in unit price as they mature. In this paper we study the unit price of liquefying natural gas in order to make it transportable by ship to gas power installations all over the world. Our point of departure is the experience curve approach, however unlike many other studies of new energy technologies, we also seek to account for autonomous technological change, scale effects and the effects of upstream competition among technology suppliers. To our surprise we find that upstream competition is by far the most important factor contributing to the fall in unit price. With respect to the natural gas business, this may have implications for the future development in prices as the effect of increased upstream competition is temporary and likely to weaken a lot sooner than effects from learning and technological change. Another more general policy implication, is that while promoting new energy technologies, governments must not forget to pay attention to competition policy.     

A novel key pre-distribution scheme for wireless distributed sensor networks

A novel key pre-distribution scheme for sensor networks is proposed, which enables sensor nodes to communicate securely with each other using cryptographic techniques. The approach uses the rational normal curves in the projective space with the dimension n over the finite field F q . Both secure connectivity and resilience of the resulting sensor networks are analyzed. By choosing the parameters q and n properly, this key pre-distribution scheme has some advantages over the previous known schemes. In addit...