白噪声驱动的高阶KdV型方程的Cauchy问题

主要研究受白噪声驱动的高阶KdV型方程的Cauchy问题.通过在某些Bourgain空间中建立双线性估计、三线性估计,并利用Ito公式、BDG不等式和停时技巧,建立相应的局部适定性和整体适定性.这些技巧可以用以研究其他具有哈密顿结构的方程的局部适定性和整体适定性.     

快速城市化下福州市的热环境变迁

福建省是国务院提出建设实施的首个"国家生态文明试验区",福州作为福建省省会,其良好的生态环境有着举足轻重的作用.针对福州在发展过程中由非"火炉"城市一跃成为中国新三大"火炉"之首的现象,利用遥感技术反演和提取地表温度及其他城市生态参数,分析它们在1989—2013年间的变化以及"火炉"形成的原因和驱动力.研究发现,在24年间福州的城市热岛效应显著加剧,反映此变化的城市热岛比例指数(URI)从0.29上升到0.53.热场剖面和时空变化分析显示,城市热场的空间结构很大程度上被土地覆盖类型的空间格局所左右.总的看来,城市不透水面面积增大,斑块集聚,植被和水体面积减少且斑块趋于破碎,加上城市通风廊道受阻,导致了福州逐渐演化成为"火炉"城市.该研究为现代城市缓解热岛效应,实现健康可持续发展提供了借鉴和支持.     

基于热固耦合的柴油机气缸盖有限元分析

针对柴油发动机缸盖失效问题,在ABAQUS软件中以某现产柴油发动机构建仿真模型,通过实验数据标定模型温度边界,运用热固耦合理论对缸盖的温度分布、应力及变形分布进行仿真分析.对于分析中发现的热应力集中的缸盖鼻梁区,提出了缸心外凸、平齐和内凹的3种对比优化设计方案,并进行仿真验证.仿真结果表明,采用缸心内凹设计,降低缸心区域壁厚,可以有效降低鼻梁区最大应力.与试验对比,仿真模型的温度分布符合实际缸盖温度分布,验证了此方法的准确性,为解决柴油发动机缸盖失效问题提供了有效的优化设计方法.     

水源热泵系统效率评价方法的研究

为了能够更准确地对热泵系统效率进行评价,对性能系数(COP)和火用效率这两种热泵系统效率的评价方法进行比较分析,并通过实验验证了两种方法得出的结论不同。火用效率评价方法弥补了COP评价方法中的不足,将两者相结合评价热泵系统效率更科学合理。     

基函数的阶数对无单元伽辽金方法精度的影响

无单元伽辽金(Element-Free Galerkin)方法是无网格方法中很重要的一种数值计算方法,利用无单元伽辽金方法求解二维稳态热传导方程,当选取基函数为线性基、二次基时,分别将数值解和解析解对比,分析了基函数的阶数对无单元伽辽金方法精度的影响,并说明无单元伽辽金方法是一种高精度的数值计算方法 .     

"气泡聚变"与冷聚变

论述了“气泡聚变”与冷聚变都属于新型聚变，指出中性粒子与核的聚变可在任何温度条件下进行，强调要用新观念与新思维来正确对待新奇核现象。     

城市民用建筑节能探讨

简要阐述了城市民用建筑节能的必要性，论述了节能应遵循的基本原则。提出民用建筑节能潜力不可估量,意义重大。     

An equation of entransy transfer and its application

Entransy is a physical quantity describing heat transfer ability, and heat transfer is accompanied by entransy transfer. Thermal energy is conserved in its transfer process, while entransy is dissipated because of the irreversibility of its transfer process. As a result, entransy transfer must have its rules which are different from those of thermal energy transfer. Based on the definition of entransy, an entransy transfer equation is derived, which describes the entransy transfer processes of a multi-component viscous fluid subject to heat transfer by conduction and convection, mass diffusion and chemical reactions. The expressions of entransy flux and entransy dissipation are obtained simultaneously, and their physical mechanism is clarified. And further, the theory and method of optimizing heat transfer applying the entransy transfer equation to the steady-state convection heat transfer process are expounded. The minimum thermal resistance principle and the entransy dissipation extremum principle are obtained by applying the steady-state entransy transfer equation to the steady-state convection heat transfer process. The cases of the single-component steady-state convection heat transfer and the steady-state heat conduction show the application of the theory and method.     

Applications of membrane distillation technology in energy transformation process-basis and prospect

Membrane distillation technology is a new type of efficient separation technology that combines traditional distillation technology and membrane separation technology. In the study, applications of membrane distillation technology in thermal engineering and refrigerating engineering with typical energy transformation process were presented. Desorption and regeneration process of saline solution by vacuum membrane distillation was proposed on the basis of the concentration and separation properties of membrane distillation. Membrane distillation technology could be used in lithium bromide absorption refrigeration system, energy storage system, and the regeneration process of liquid desiccant solution in temperature-humidity independent control air-conditioning system. The aim of the applications was to use the low-grade energy such as waste heat, solar energy and geothermal energy adequately and to improve the available temperature difference of heat source. According to latent heat transfer and thermal conduction across the membrane in direct contact membrane distillation process, a novel membrane heat exchanger with both heat transfer and mass transfer processes was proposed. The heat exchanger could be used as the solution heat exchanger of lithium bromide absorption refrigeration system and as the special heat exchanger that recovered heat and pure water simultaneously. Some feasible process flows about the applications of membrane distillation technology to energy transformation process were listed and analyzed. Finally, future research emphases were indicated.     

Entropy generation extremum and entransy dissipation extremum for heat exchanger optimization

The applicability of the extremum principles of entropy generation and entransy dissipation is studied for heat exchanger optimization. The extremum principle of entransy dissipation gives better optimization results when heat exchanger is only for the purpose of heating and cooling, while the extremum principle of entropy generation is better for the heat exchanger optimization when it works in the Brayton cycle. The two optimization principles are approximately equivalent when the temperature drops of the streams in a heat exchanger are small. Supported by Major State Basic Research Development Program of China (Grant No. 2007CB206901)