Photocatalytic degradation of phenol with mesoporous TiO2?xBx

We report a facile approach for preparing mesoporous boron-doped TiO₂ materials by combining the sol?Cgel process with the dehydration of glucose. Specifically a high surface carbon material was formed by dehydration of glucose, then used as template. This material and the TiO₂ dry gel were calcinated to produce porous TiO₂. The as-synthesized boron-doped TiO₂ was in pure anatase crystallite phase with high surface area. X-ray photoelectron spectroscopy (XPS) results showed that boron was incorporated into the anatase TiO₂ lattice to form TiO_2?xB_x. The absorption spectra of TiO_2?xB_x extended into the visible region to 460?nm. The TiO_2?xB_x exhibited much higher photocatalytic activity on phenol degradation than pure TiO₂. It showed that the phenol degradation by-products of TiO_2?xB_x were different from that of pure TiO₂. Mechanism of the photocatalytic degradation of phenol at TiO_2?xB_x was also proposed.     

基于CNN-GRU的瓦斯浓度预测模型及应用*

为解决传统瓦斯浓度预测方法预测精度低和适用性不强等问题,提出运用卷积神经网络（CNN）提取瓦斯浓度时间序列的变化趋势及局部关联特征,应用门自适应矩估计（Adam）优化的控循环单元神经网络（GRU）,在关联特征基础上进行时序性预测的组合方法,并以铜川玉华煤矿监测数据为样本,对比CNN-GRU组合模型、传统机器学习模型LSTM和GRU模型的预测效果。研究结果表明:CNN-GRU模型的预测精度和收敛速度均优于LSTM和GRU模型;CNN-GRU平均绝对误差和均方根误差分别可降低至0.042,0.006,运行效率分别提高59.15%,35.04%,研究结果可为矿井瓦斯灾害防治提供依据。     

基于酸催化的生物质制乙醇工艺条件优化

纤维素乙醇被认为是最佳的替代燃料之一,但依然存在纤维素水解效率低和水解糖液中有害物质影响酵母菌活性等问题,从而导致其生产成本过高,无法实现工业化生产。选取水稻秸秆、小麦秸秆、高粱秸秆、毛竹等4种典型生物质,进行了基于酸催化法与同步酶解发酵法制取纤维素乙醇工艺条件的优选研究,采用DNS还原糖测定法测定原料还原糖转化量以表征预处理效果,并使用气相色谱法测定乙醇转化率。结果表明:水稻以5%固体装载量在125℃下经0.5%稀硫酸处理10 min后,产糖率达28.74%,处理效果在4种生物质中最优;发酵2 d后的水稻和小麦的乙醇转化率分别为51%和54%,显著高于高粱与毛竹;发酵5 d后高粱和毛竹的乙醇转化率达到了61%和65%,高于水稻和小麦。以上结果对改善传统生物质生产纤维素乙醇产率低的问题,具有一定的实际指导意义。     

提高军官常服皮鞋穿着与视觉舒适性探讨

本文通过军人脚型测量分析、军鞋审美取向调查分析、军鞋重量与运动性能试验分析等探讨研究,获得了脚型、式样、重量等相关数据,对于新式军鞋研究、生产和使用具有一定的参考作用。     

室内环境安全及污染控制

近年来室内装修污染健康危害事件不断发生,成为居民投诉的热点,室内环境安全也已成为学术界和政府部门关心的焦点.本文以九江地区室内环境质量状况为例,指出了室内空气污染的来源,分析了各种室内主要污染物对人体健康的影响,对如何防治室内污染,达到居住环境安全的问题进行初步的探讨.     

小径管焊口未焊透深度射线检测特殊工艺

本文介绍了JB/T 4730.2-2005标准未能涵盖的、适用于在用压力管道的小径管焊口未焊透深度射线检测的一种特殊工艺,并配套设计了特殊的未焊透深度RT对比试块。     

采用模拟试验方法对一起一氧化碳中毒死亡事故的分析

运用模拟试验的方法查清了一起CO中毒死亡事故的原因,查明了事故的直接责任者,确定了石灰窑停窑操作的关键步骤,为今后避免类似事故提供参考.     

Chemical poison and regeneration of SCR catalysts for NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> removal from stationary sources

Selective catalytic reduction (SCR) of NO _x with NH₃ is an effective technique to remove NO _x from stationary sources, such as coal-fired power plant and industrial boilers. Some of elements in the fly ash deactivate the catalyst due to strong chemisorptions on the active sites. The poisons may act by simply blocking active sites or alter the adsorption behaviors of reactants and products by an electronic interaction. This review is mainly focused on the chemical poisoning on V₂O₅-based catalysts, environmental-benign catalysts and low temperature catalysts. Several common poisons including alkali/alkaline earth metals, SO₂ and heavy metals etc. are referred and their poisoning mechanisms on catalysts are discussed. The regeneration methods of poisoned catalysts and the development of poison-resistance catalysts are also compared and analyzed. Finally, future research directions in developing poisoning resistance catalysts and facile efficient regeneration methods for SCR catalysts are proposed.     

世界粮食日纪念币

2004年10月16日是“联合国粮农组织”确定的第24个“世界粮食日”。