Long-term stability of an Au/Al2O3 catalyst prepared by incipient wetness in continuous-flow glucose oxidation

A 0.3% Au/Al₂O₃ catalyst prepared by the incipient wetness (IW) method was investigated in the continuous-flow liquid-phase glucose oxidation. Therefore, a continuous stirred tank reactor (CSTR) system equipped with an ultrasonic separator was used. The continuous-flow glucose oxidation was carried out at 40 °C, pH 9 and 1 bar oxygen partial pressure. Residence time and glucose concentration were varied. The IW gold catalyst showed very high activity and selectivity to gluconic acid within its 110 days of operation and, thus, an excellent long-term stability. Even after severe microbial contaminations of the catalyst, its activity could be completely restored by in situ regeneration with 2-propanol.     

基于互补原理确定黄土高原Budyko方程的流域特性参数

Budyko方程的流域特性参数一般根据植被覆盖度等下垫面特征进行确定,但相关资料不易获取。本文针对黄土高原地区29个小流域,通过分析流域特性参数、植被覆盖度和互补关系中大气湿润指数之间的关系发现,大气湿润指数能够间接反映植被覆盖度的大小,进而能够利用常规气象数据确定流域特性参数,并拟合出了经验公式。相比采用固定流域特性参数,这种方法能够提高Budyko方程对实际蒸散发量的模拟效果。相比于植被覆盖度等下垫面资料,常规气象数据时间序列长、且更易获取,因此本方法具有较好的应用前景。     

金属基复合材料制备中有害界面反应的控制和润湿性的改善工艺

介绍了液态法制备颗粒增强金属基复合材料（以SiCp／Al为例）过程中，如何控制增强相颗粒和基体之间发生的有害界面反应、改善增强颗粒与基体润湿性的常用方法。结果表明，添加Si元素、添加Ti、Zr、Nb、V等合金元素、表面涂覆和处理以及控制工艺方法和参数都可有效地抑制有害的界面反应发生和改善基体和增强相的润湿性。     

表面活性剂对甘蓝叶子润湿性能试验

研究了十二烷基硫酸钠（SDS），十二烷基苯磺酸钠（LAS），烷基酚聚氧乙烯醚（OP－10），异辛醇聚氧乙烯醚（JFC）以及LAS与OP复配体系对甘蓝叶子的润湿性能。结果表明：单一表面活性剂OP润湿性能较好，LAS与OP复配体系的润湿性能与OP相近。     

干旱灾害成灾过程数值模拟研究

以有限区域大气运动模式和土壤水热传导模式为基础,采用地表水分蒸发、地表水渗透、植被的蒸腾作用与根系吸水作用、地面风场4种过程作为模型的耦合方案,建立了用于干旱灾害成灾过程数值模拟的数学耦合模型.利用该数学模型模拟计算了1995年7月1～30日发生在长江中下游地区的干旱灾害,其干旱过程可分为土壤可供水量满足农作物需水量阶段、根系层土壤供水量小于农作物需水量阶段、农作物干旱阶段3个阶段,实践证明该模型对干旱灾害的发生发展过程具有很好的模拟能力.     

巷道断面与风筒断面形状对局部通风工作面热环境模拟结果的影响

在运用计算流体力学(CFD)的方法模拟解算矿井热环境时,为了便于对直角坐标中计算域的网格划分和离散化方程的简化,经常对巷道和风筒的几何形状进行假设或简化成规则的形状.对应用计算流体力学的方法模拟局部通风掘进工作面热环境时巷道断面形状、风筒出口形状等对模拟解算结果的影响进行了解算和分析.     

基于GIS考虑准动态湿度指数的滑坡危险性预测水文-力学耦合模型研究

降雨在区域浅层滑坡灾害危险性预测研究中起着关键作用。为综合斜坡地形因素和由降雨引起的地表水下渗、地下水径流对斜坡稳定性的影响,结合基于物理过程的无限斜坡模型和基于数字高程模型 DEM 的简化运动波模型,提出考虑准动态湿度指数的滑坡危险性预测水文-力学耦合模型。该模型基于地理信息系统GIS平台,采用矢量-栅格复合单元对斜坡进行危险性分析(即以斜坡单元为基本研究对象,用栅格数据进行单个斜坡单元稳定性分析)。首先,基于极限平衡理论推导无限斜坡模型;然后,在考虑降雨强度以及持续时间的情况下应用简化的运动波模型计算降雨入渗和地下水径流作用过程中的地形准动态湿度指数,得到滑坡土体饱和因子在时间和空间上的分布情况,并在此基础上实现水文模型与无限斜坡模型的耦合;最后,以三峡库区巴东新城区滑坡灾害危险性预测为例,验证模型在区域浅层滑坡灾害危险性预测中具有较高的精度。     

Enhanced gas-condensate production by wettability alteration to gas wetness

Many gas-condensate reservoirs experience a sharp drop in gas production due to condensation near the wellbore as pressure drops lower than the dew point. Wettability alteration approach has been demonstrated successful in laboratory. However few experiments have been conducted in real reservoir rock with a low permeability. The gas-condensate reservoirs impaired by condensation near the wellbore usually have low permeabilities. In this study, we conducted experiments in the rock sampled from the target gas field (Dongpu). Firstly a new and cheaper chemical was developed to change the rock wettability from preferential water- to gas-wetness effectively. This chemical was thermally stable at a temperature of 170 °C. Experimental results also showed that this chemical was effective at very high salinity. Secondly spontaneous water imbibition tests were run to show the effect of wettability alteration on recovery. Thirdly relative permeability data of gas and water were measured with and without wettability alteration to preferential gas-wetness. Experimental results demonstrated that the relative permeabilities of both the gas and the water phases were increased significantly after the wettability alteration to preferential gas-wetness. The residual water saturation was decreased and the gas production was enhanced greatly due to the wettability alteration.     

Effects of loading transition metal(Mn,Cr,Fe,Cu) oxides on oxygen storage/release properties of CeO_2-ZrO_2 solid solution

Cerium zirconium-based(CZ) oxygen storage materials(OSMs) play a crucial role in three-way catalysts(TWCs),while CZ needs to be modified to satisfy more rigorous emission standard.In this study,transition metal(TMs=Mn,Cr,Fe,Cu) oxides modified CZ were prepared by incipient wetness impregnation method to improve the oxygen storage capacity of CZ-based materials.To clearly illustrate the influence of TM oxides,N_2 adsorption-desorption,X-ray diffraction(XRD),oxygen storage capacity(OSC),temperature programmed reduction by H_2(H_2-TPR) and X-ray photoelectron spectroscopy(XPS) were used to characterize the physical and chemical properties of samples.It is found that,all modified CZ have higher OSC,lower reduction temperatures than those of pristine CZ.Interaction between TMOs and CZ take precedence over specific surface to influence OSC.Notably,FeO_x/CZ has the highest OSC,which is about 1.9 times that of CZ and it could be attributed to synergistic effect between FeO_x and CZ;CuO_x/CZ has the lowest reduction temperature which is 168℃lower than that of CZ,and it can be explained by hydrogen spillover effect.     

基于双区加热法的汽轮机蒸汽湿度测量误差分析研究

蒸汽湿度对汽轮机的安全性和经济性有着重要的影响。基于双区加热法湿度测量理论,本文充分考虑到取样流量、散热损失以及汽化长度等因素对双区加热探针湿度测量方法的影响,通过建立数学模型,对双区加热法测量原理及测量误差进行分析,为优化探针结构设计、提高测量精度提供了理论依据。