基于时空消耗理论的城市快速路长度计算方法

随着城市交通压力的不断增大,我国许多大中型城市都展开了快速路建设的热潮,针对城市快速路网长度的研究,基于供需平衡的原理,文章提出一种基于时空消耗法的快速路网长度计算方法,使快速路的时空总量等于快速路上所有车辆的时空总量,进而得到快速路长度计算模型,并应用到济南市快速路计算实例中。计算结果与济南市快速路实际规划里程相对一致,此方法可以作为确定城市快速路规划里程的计算依据。     

气-液-固三相流化床冷态实验

以氮气为气相、蒸馏水为液相、铜粉为固相构建了的气-液-固三相流化床冷态实验装置,流化床反应器内径为50 mm、高为500 mm.采用Hilbert-Huang Transform分析了布风板上表面处压力脉动信号,考察了布风板压差和床内两固定测点间压差随气体流速的变化关系,使用降速法得到了气-液-固三相流化床的最小流化速度,并通过同步图像采集验证了该最小流化速度.结果表明:气体流速为14.85 mm/s时,固体颗粒之间碰撞剧烈,气、液、固三相混合均匀;随着气体流速的增加,两固定测点间压降呈现先降低,后增加,最后又降低的变化趋势;气-液-固三相流化床的最小流化速度约为17.4 mm/s.     

乙酸乙酯合成反应液的快速气相色谱分析

利用充填有GDX—104(60～80目)的不锈钢色谱柱,以氢气做载气,TCD检测器检测,分析了乙酸乙酯合成反应液中反应物与产物的含量。本方法的精密度与准确度均较高,RSD为0.89％,回收率为99.5％,难分离物质对的分离度R>1.2,分析时间小于3min。     

Superfine Spherical Hollow Ammonium Dihydrogen Phosphate Fire-Extinguishing Particles Prepared by Spray Drying

Superfine spherical hollow ammonium dihydrogen phosphate fire-extinguishing particles are prepared by spray drying and modified in situ with silicon oil emulsion. The results show that the amount of rough particles increased observably when the proportion of silicon oil emulsion is increased from 9 to 15 wt%, while no significant difference is detected when the proportion of silicon oil emulsion was varied from 0 to 9 wt%. The flowability of particles is improved with an increase in the proportion of silicon oil emulsion; 9.0 wt% is the optimal proportion of silicon oil emulsion for improving the hydrophobic performance of particles. Fire-extinguishing tests show that the fire-extinguishing capability of spray-dried superfine spherical hollow ammonium dihydrogen phosphate fire-extinguishing particles is much better than the two varieties of existing superfine dry chemical fire-extinguishing agents.     

Phase separation of impact‐modified PVC/PMMA blends under melt‐blending conditions

Poly (vinyl chlride)/Poly (methyl methacrylate) (PVC/PMMA) blends were prepared by melt blending at 160°C and 190°C over an entire composition range. The miscibility of the blends was characterized by dynamic mechanical thermal analysis, transmission electron microscopy, and light transmittance testing. The blends prepared at 160°C were homogeneous on our observed scale, while the blends prepared at 190°C clearly showed phase separation. The stress‐strain behaviors of the blends prepared at 160°C were investigated. The results showed that the toughness of the blends could be improved by an increase of PVC content, resulting effectively in a removal of intrinsic strain softening, a decrease in yield stress, and an increase in strain hardening. Furthermore, a core‐shell structured modifier was introduced into the PVC/PMMA blends, and the impact property of the blends was studied. The results showed that the addition of rubber particles could improve the toughness of the two series of blends. However, the blends prepared at 190°C had higher impact strengths than those prepared at 160°C, a result which may be attributed to phase separation. J. VINYL ADDIT. TECHNOL., 19:11–17, 2013. © 2013 Society of Plastics Engineers     

Study on compression–expansion behaviour of PBXs substitutive materials

ABSTRACT

In this work, polymer-bonded sugars were used as a substitutive material for polymer-bonded explosives (PBXs). Their production process and damage mechanism under compressive process were analysed. We also investigated the initial Poisson’s ratio of PBXs as well as their mechanical properties under quasi-static compression and variation of Poisson’s ratio during the one-dimensional compressive process. Compressive expansion behaviour due to compressive loading was investigated comprehensively. It was found that due to the damage caused by the loading process, volumetric strain and Poisson’s ratio showed three stages characteristic. Experimental results proved that compression–expansion had occurred during the one-dimensional compressive process. Simulation results verified that PBXs crystal underwent mainly transgranular fracture under quasi-static compression.     

多孔波纹板错流旋转床流体力学性能研究

以空气-水为介质,研究了两种板间距填料结构的流体力学性能。结果表明：多孔板错流旋转床气相压降随填料板数、气量、超重力因子的增加而增大,与液量几乎无关;在相近操作条件下该床压降不足逆流床的1／10;应用MATLAB语言编制应用程序对实验数据的回归分析得出了气相压降的关联式。     

不同微生物发酵剂及木醋液在草炭发酵中应用效果研究

草炭与硬杂木锯末以2．6：1比例混匀后，接种不同微生物发酵剂和喷施500倍木醋液，在温室里容积为2．5m^3的发酵槽中进行对比试验，试验结果：喷施500倍木醋液比对照最高发酵温度高7℃，平均发酵温度高4℃；大于40℃以上中高发酵温度多7天；HA总比对照增加11．47％，HA游含量也略高于对照。在只接种微生物发酵剂的处理中，最高发酵温度是酵素菌56℃〉高温纤维分解菌55℃〉秸秆速腐剂54℃〉EM53℃〉对照46℃；在喷施木醋液条件下接种发酵剂，最高发酵温度是高温纤维分解菌57℃=酵素菌57℃〉速腐剂50℃〉EM48℃。HA总及HA游含量也是高温纤维分解菌＋木醋液与酵素菌＋木醋液两个处理明显高于对照及其他接种剂处理。     

变截面管沿壁薄膜压力计算

本文对自调匀整器中的气体压力传感器的压力分布进行了研究,利用二维 N—S 方程计算出沿壁薄膜内压力分布的表达式。从而,为气体压力传感器的传压孔位置的确定提供可行的方法。     

Facile Synthesis of Fluorine Doped Rutile TiO2 Nanorod Arrays for Photocatalytic Removal of Formaldehyde

Catalysis Letters - It is crucial to explore a facile synthesis of rutile TiO2 nanorods anchored at carbon cloth at low temperature for applicable air purifier. Herein, antler-like TiO2 rectangular...