Micro-Raman investigations on the structures of the surface and the inner of MgSO<Subscript>4</Subscript> droplets

Spherical MgSO4 droplets were deposited by a syringe on the hydrophobic Teflon substrate. Using micro-Raman technique, the laser beam was highly focused twice on the surface and in the center of spherlcel droplets. The Raman spectra for the surface and the inner of MgSO4 droplets were accordingly obtained, suggesting formation of a thin layer of gels on MgSO4 droplets at low relative humidity. The gel layer covered the surface and exhibited a significant delay in response to the change of amblent relative humidity, resulting in the structural difference between the surface and the inner of MgSO4 droplets.     

Micro-Raman investigations on the structures of the surface and the inner of MgSO_4 droplets

Spherical MgSO4 droplets were deposited by a syringe on the hydrophobic Teflon substrate. Using micro-Raman technique, the laser beam was highly focused twice on the surface and in the center of spherical droplets. The Raman spectra for the surface and the inner of MgSO4 droplets were accord-ingly obtained, suggesting formation of a thin layer of gels on MgSO4 droplets at low relative humidity. The gel layer covered the surface and exhibited a significant delay in response to the change of ambi-ent relative humidity, resulting in the structural difference between the surface and the inner of MgSO4 droplets.     

卷积型加权残值法求解梁的瞬态热传导问题

通过卷积将热传导方程构造成包含初始条件的新的具有完整初值问题特征的控制方程．对于新的控制方程以伽辽金加权残值法进行求解,经对梁的瞬态热传导问题的计算表明,该方法是一种精度好效率高的求解热传导同题的计算方法．     

燃料电池轿车用PCU水冷装置的设计与试验

提出了一种燃料电池轿车用DC/DC,DC/AC集成系统动力控制单元(PCU)的高效低阻水冷装置的设计方法.根据强化传热原理,将发热元件贴在水冷装置上,热量传导到装置内部,再由对流换热传递给冷却水带出到外部冷却设备进行散热.采用加菱形肋柱强化散热的设计思路,增加散热面积,同时由于肋柱使流道面积减小,冷却液流速增大,能有效地提高PCU的工作效率、增加工作寿命、改善工作条件.最后建立了试验测试平台进行验证.     

试重组迁移矩阵及现场混合动平衡方法

针对全息动平衡方法在现场应用中可能存在因试重起车次数受限、无法获得足够的转子特征响应参数的问题,提出了一种基于试重组的全息现场混合动平衡方法．借鉴Darlow混合法中模态试重组的思想,通过对模态试重比的简化假设,利用迁移矩阵的线性可叠加性将对应于某单一平衡面的迁移矩阵扩展为对应于某阶模态试重组的迁移矩阵,从而减少了平衡高阶不平衡量所需的试重起车次数,提高了现场平衡效率,且平衡效果良好．通过对一台300MW汽轮发电机组的现场动平衡过程的试验分析,表明了该方法的可行性和有效性．     

基于逆边界元法的内燃机噪声源识别方法

对内燃机复杂噪声源进行识别和排序是内燃机噪声控制的关键．基于逆边界元法（IBEM）的噪声源识别技术,利用边界元法建立了声场与结构表面振动速度之间的声学传递向量（ATV）．将常规的声压测量作为输入数据,在逆向数值计算方法的基础上能够精确地重构出结构表面法向振动速度,进而获得源面详细的振声特征信息．针对某轿车柴油机,测试了额定工况下近场144个场点声压,应用该方法在发火频率点处,重构出了柴油机表面法向振动速度分布．通过对比预测和实测声场点声压,验证了该方法的有效性．在噪声面板贡献量分析的基础上,对该柴油机各功能部件的噪声贡献量进行了排序,并得知额定工况下该柴油机的机体裙部是主要的噪声辐射部位．应用实例说明了该方法对复杂噪声源识别易于实施。具有更广的工程适应性．     

FC-空间中的极大极小不等式和鞍点定理

利用交定理,在不具有任何凸结构的FC-空间中证明了一些极大极小不等式和一个鞍点定理．     

Analysis of contact melting around a horizontal elliptical cylinder heat source

The process of AT-driven contact melting of the solid phase change material （PCM） around a horizontal elliptical cylinder heat source is analyzed. Aiming at the problem existed in the published literature, namely the thickness of boundary layer tends to be infinite at φ = 90°, and considering the difference of normal angle between the horizontal elliptical cylinder surface and the solid-liquid interface of PCM, a new mathematic model is proposed, and the fundamental equations for the melting process are derived with the film theory. The new pressure distribution inside the boundary layer, the variation law of normal angle of the solid-liquid interface, the thickness of the boundary layer and the relationship between the melting velocity and resultant force are obtained. The solutions of the fundamental equations under different elliptical compression coefficients are analyzed and discussed. It is found that the thickness of the boundary layer obtained by the new model is a finite value and accords with the experimental result at φ = 90°.     

污水土地处理系统污染物迁移转化的模拟研究

综合考虑污染物在土壤中的生物吸收作用、机械吸收作用、化学吸收作用、土壤胶体的吸收作用和代换性吸收作用,建立了污染物在土壤中的迁移转化模型,模拟计算土壤中各种污染物在迁移转化过程中的浓度变化,为污水土地处理的管理和控制提供了定量化依据．     

基于资源流转的乡村旅游地社会发展研究

乡村旅游地的旅游开发必然引起自然资源、文化资源、基础设施、旅游服务设施等资源要素的重组。资源要素重组过程中会导致城乡发展反向性与一体化的对立、城乡环境乡土性与现代化的对立、旅游经营本土性与飞地化的对立、收入分配市场性与小康化的对立,不利于乡村旅游地的可持续发展。本文构建了基于资源流转的乡村旅游地社会发展模型,分析了乡村旅游地的发展趋势、动力系统及其矛盾,并从制度以及技术层面提出了乡村旅游地资源优化配置的对策。