巷道的空气动力时效对通风系统可靠性的影响

通过对老虎台煤矿各类巷道的空气动力时效变化对通风系统可靠性影响的调查，分析了时效变化的影响因素、危害，提出了时效变化对通风系统可靠性影响的处理措施。

THERMAL EFFECTS OF BUILDING′S EXTERNAL SURFACES IN CITY——Characteristics of Heat Flux into and out of External Wall Surfaces

This study examined the thermal effects of building′s external wall surfaces, using observational data of spatial-temporal distribution of surface temperature, air temperature, and heat flux into and out of external surface. Results indicate that external wall surface temperature and nearby air temperature vary with the change of orientation, height and season. In general, the external wall surface temperature is lower near the ground, and is higher near the roof, than nearby air temperature. But north wall surface temperature is mostly lower than nearby air temperature at the same height; south wall surface temperature during the daytime in December, and west wall surface temperature all day in August, is respectively higher than nearby air temperature. The heat fluxes into and out of external wall surfaces show the differences that exist in the various orientations, heights and seasons. In December, south wall surface at the lower sites emits heat and north wall surface at the higher sites absorbs heat. In April, all external wall surfaces, emit heat near the ground and absorb heat near the roof. In August, west wall surface all day emits heat, and other wall surfaces just show the commensurate behavior with that in April.

添加Y对富铜纳米相强化铁素体钢拉伸性能的改善

针对富Cu纳米相强化铁素体钢空气时效后拉伸脆断的问题,选取含与不含Y的2种对比合金钢进行相关研究。采用光镜(OM)、扫描电镜(SEM)观测了钢的基体组织、断口及氧化层;高分辨透射电镜(HRTEM)和X射线能谱(EDS)分析了纳米析出相的形貌、尺寸、数量密度、化学成分和晶体结构。结果表明:含Y钢中的含Y富Cu纳米析出粒子平均尺寸变大但数量密度降低,铁素体晶粒变细,钢的拉伸强度、塑韧性改善;Y的拖曳效应使氧化层变薄且钢基体-氧化层、氧化层之间结合牢固。富Cu纳米相强化铁素体钢空气时效后拉伸性能的改善,来源于Y的细化晶粒、抗氧化和净化效果。