Promotional effect of Ce on the activity of In/W–ZrO2 for selective reduction of NO x with methane

The Ce modified In/W–ZrO₂ catalysts were prepared by impregnation and mechanical mix method. Their activities for SCR of NO _x with methane were investigated. The activity of the In/W–ZrO₂ catalyst was enhanced by addition of Ce with both methods, while the promotional effect was more pronounced for catalyst prepared by mechanical mix method compared to impregnation method. The function of Ce was to improve the oxidation of NO to NO₂. The maximum NO _x conversion over the mechanical mixed catalyst can be stabilized at 74% at 450 °C in a dry gas flow and 37% at 500 °C in wet flow (24,000 h⁻¹). For the impregnated catalysts, Ce was found to compete with In to adsorb on strong acid site over W–ZrO₂ support and inhibited the formation of InO⁺, which resulted in the lower activity of these catalysts than mechanical mixed catalysts.     

温度对Cr26Mo1超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响

通过循环极化曲线、Mott-Schottky曲线以及电化学阻抗谱等方法研究了温度对Cr26Mol超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响.结果表明:随着温度升高,Cr26Mol超纯高铬铁素体不锈钢的自腐蚀电位降低,腐蚀电流密度增大,点蚀电位下降,钝化膜阻抗降低.Cr26Mol不锈钢钝化膜的半导体类型和性质在不同温度下发生改变.Cr26Mol不锈钢发生点蚀的孕育期随着温度的升高而缩短,点蚀敏感性增加,已发生点蚀的试样不能够自修复.     

温度对Cr26Mol超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响

通过循环极化曲线、Mott-Schottky曲线以及电化学阻抗谱等方法研究了温度对Cr26Mo1超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响.结果表明:随着温度升高,Cr26Mo1超纯高铬铁素体不锈钢的自腐蚀电位降低,腐蚀电流密度增大,点蚀电位下降,钝化膜阻抗降低.Cr26Mo1不锈钢钝化膜的半导体类型和性质在不同温度下发生改变.Cr26Mo1不锈钢发生点蚀的孕育期随着温度的升高而缩短,点蚀敏感性增加,已发生点蚀的试样不能够自修复.     

VMI模式下成本控制优化与物料配送研究

在VMI模式下对库存成本控制与物料配送进行了深入研究,建立了基于时间发货策略的库存成本控制与物料配送模型。对库存成本进行分解得到了完整的总成本表达式,通过优化方法对模型进行求解得到了最优化发货周期、补货数量与最小库存成本。研究结果有助于增强企业快速响应市场需求的能力,降低企业的投入成本,提高企业的竞争能力。模型在企业分销系统中得到了实例应用。     

大理石-萤石型碳钢焊条电弧物理特性分析

采用汉诺威焊接质量分析仪对大理石-萤石型碳钢焊条电弧物理特性进行了研究,发现熔滴的"桥内过渡"是大理石-萤石型碳钢焊条熔滴行为的主要特征,提出以T1＞2.05 ms时间段内短路频率N与该时间段内累计的短路时间∑(T1)作为判据,评价大理石-萤石型碳钢焊条的工艺性.     

一种简易数控非圆截面的车削

设计了一种加工非圆零件的简易数控车床,通过对凸轮零件加工的分析计算,提出了消除因伺服系统的滞后所造成的加工零件拐角处的偏差的方法,并在实际编程加工中验证该方法的可行性,同时也充分证明了该设计的实用性.     

Platinum supported on reduced graphene oxide as a catalyst for hydrogenation of nitroarenes

Reduced graphene oxide (RGO)-supported platinum (Pt) catalyst was prepared by simple ethylene glycol (EG) reduction and used for hydrogenation of nitroarenes. Characterizations showed that EG as a reductant exhibited more advantages than the widely used hydrazine hydrate to fabricate monodispersed, small sized Pt nanoparticles on the surface of RGO. The yield of aniline over the Pt/RGO-_EG catalyst reached 70.2 mol-_AN/(mol-_Pt min) at 0 ^oC, which is 12.5 and 19.5 times higher than that of multi-walled carbon nanotube- and active carbon-supported Pt catalysts, respectively. When the reaction temperature was increased to 20 ^oC, the catalytic activity of Pt/RGO-_EG jumped to 1138.3 mol-_AN/(mol-_Pt min), and it was also extremely active for the hydrogenation of a series of nitroarenes. The unique catalytic activity of Pt/RGO-_EG is not only related to the well dispersed Pt clusters on the RGO sheets but also the well dispersion of Pt/RGO-_EG in the reaction mixture.     

液化气钢瓶车载GPS移动配售系统

根据"十二五"上海燃气转型发展新形势,液化石油气用户将呈现分布范围广、不均匀、流动性大的特点,通过国内外液化气行业移动配送系统应用现状与趋势分析,结合上海实际,上海液化石油气经营有限公司开发了基于上海燃气服务平台,利用GPS设备运用于液化气钢瓶车辆配送、销售的集成系统并成功运用,以期对推动行业更及时、准确地实现瓶装液化气全配送服务。     

Climate history of the middle reach of the Yangtze river over the past 9000 years: A speleothem isotopic record from Za cave,Hubei, China

A stalagmite in Qingjiang, Hubei, has yielded the records of hydrogen and oxygen as well as carbon isotopic changes and provided a climate history of 9000 years. The hydrogen isotopic ratio in fluid inclusions and the oxygen isotopic ratio in stalagmite calcite are controlled by meteoric water, which is in response to ambient temperature or precipitation amount. The carbon isotopic ratio, sensitive to the nature of vegetation, also can be used to reconstruct the climate history. The carbon-14 and U-series dated stalagmite records reveal that climate oscillated in the middle reach of Yangtze river over the past 9000 years: (1) 9.0-6.5 kaBP, a cooler and more humid condition; (2) 6.5-4.0 kaBP, with warmer and drier weather; (3) 4.0-2.0 kaBP, cold weather with heavy precipitation, and (4) 2.0 kaBP to present, tendency to be warmer and drier.

     

碘化多壁碳纳米管制备含有Ag/MWCNTs复合材料的银-环氧树脂浆料

提出一种将多壁碳纳米管碘化后制备银/多壁碳纳米管（Ag/MWCNTs）复合材料的方法。通过球磨对碘化多壁碳纳米管进行了功能化,并通过透射电子显微镜（TEM）、X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、拉曼光谱和热重分析（TG）对其进行了表征。结果表明,经碘化处理后,银纳米粒子（Ag-NPs）能更好地粘附在碳纳米管表面,改善了银纳米粒子与碳纳米管之间的连接。羟基（-OH）基团的伸缩振动明显增强,激活了碳纳米管的表面,增加了碳纳米管表面Ag⁺形核的数量。在260 ℃以下,Ag/MWCNTs复合材料的质量损失小于MWCNTs的质量损失。最后,制备了银-环氧树脂浆料,发现使用Ag/MWCNTs复合物制备的浆料具有最低的电阻率和最高的热导率。