Influence of inorganic anions and organic additives on photocatalytic degradation of methyl orange with supported polyoxometalates as photocatalyst

A novel supported polyoxometalate(POM),phosphotungstic acid immobilized into yttrium-doped TiO2(HPW-Y-TiO2) nano photocatalyst was prepared via sol-gel and impregnation method.The samples were characterized using Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD) and N2 absorption-desorption analysis.The results showed that the supported POM exhibited Keggin structure and anatase phase with large BET surface area.The influences of inorganic anions and organic additives on the photocatalytic degradation of azo dye methyl orange with HPW-Y-TiO2 as photocatalyst under UV light(λ≥365 nm) were investigated.Results showed that inorganic anions Cl-,SO42-,CO32-and NO3-had inhibition effect on the degradation of methyl orange.A great enhancement of degradation rate was obtained while H2O2 and ethyl alcohol were applied.The degradation rates improved with the increase of H2O2 concentration.The optimum additive amount of ethyl alcohol was 0.5 mol/L.The possible mechanisms of the effects of additives on methyl orange degradation were discussed.     

Photocatalytic degradation of methyl orange by polyoxometalates supported on yttrium-doped TiO_2

A series of novel photocatalysts, H3PW12O40-Y-TiO2 nanocomposites with different H3PW12O40 loading levels (10%-40%) were prepared by impregnation method. And the Y-TiO2 support, doped with yttrium, was synthesized via sol-gel technique. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), nitrogen adsorption-desorption analysis and scanning electron microscopy (SEM). The processes allowed obtaining Keggin structure and crystallized anatase with large BET surface area as well as uniform distribution. The effects of H3PW12O40 loadings, catalyst dose, initial pH and concentration of dye solution on the degradation kinetics of methyl orange under UV light (λ≥365 nm) were discussed. Kinetics studies showed that the photocatalytic degradation of methyl orange fitted the apparent first-order reaction. Methyl orange was totally degraded in 21 min under optimum conditions: 20% loading, 0.03 g dose and pH 1.0. The catalyst was stable and easily to be separated from reaction system for recovery.     

含CO2天然气井井喷流场特征

为研究含CO2天然气井井喷后的流场特性进而为确定安全防护距离提供科学依据,采用流体力学理论与计算流体力学(CFD)技术相结合的方法分析了井喷的流场特征,阐述了井喷流场各个阶段的扩散机理,模拟所需的定解条件及数值计算方法.井喷整个过程可划分为临界流、等熵膨胀、可压缩射流、不可压缩射流、重气扩散和非重气扩散6个阶段.采用CFD模拟方法模拟得出含CO2天然气井井喷气体速度场,气体膨胀速度可达700 m/s以上;分析了CO2浓度分布规律,在等熵膨胀区的内层区域CO2气体质量浓度均匀分布,而在外层区域内,CO2 的质量浓度急剧降低,CO2质量浓度随扩散距离的变化符合高斯分布.理论预测与模拟结果具有很好的一致性,表明提出的井喷流场理论分析与CFD模拟方法是切实可行的.     

电爆炸箔加速飞片的动力学模型

本文分析了爆炸金属箔加速飞片的物理过程，介绍计算飞片速度的经验模型和动力学模型。在动力学模型的计算中，利用高斯曲线形的拟功率曲线代替实测功率曲线。飞片速度的计算结果与实验符合较好。     

阴离子交换纤维的制备及吸附Cr(Ⅵ)性能研究

采用共辐射引发接枝共聚法在聚丙烯纤维上接枝苯乙烯-二乙烯苯,通过氯甲基化反应和胺化反 应制备强碱性阴离子交换纤维。当单体体积分数为20％-25％,辐射剂量率为1.2~1.8 kGy/h时,接枝率 可以控制在150%~250%。当氯甲基化反应温度(38±2)℃,反应时间15~25 h,胺化反应温度(30±2)℃, 反应时间15-20 h时,制备的强碱性阴离子交换纤维交换容量达到3.00 mmol/g以上。将该纤维对Cr(Ⅵ) 进行吸附试验,结果纤维对Cr(Ⅵ)的吸附以液膜扩散为主,吸附速度很快,8 min可达到吸附饱和,吸附反应 速率常数为0.015 s-1,静态吸附饱和容量为257.6 mg/g,吸附行为符合Freundlish等温吸附模型。     

沟槽式爆炸逻辑网络炸药技术的发展

综述了沟槽式爆炸逻辑网络炸药技术的国内外发展状况，包括配方的选择、炸药安全性、混药、压药和装药等工艺研究，并提出了我国今后的研究方向。     

炸药爆炸事故冲击波,热辐射和房屋倒塌的伤害效应

讨论了冲击波伤害机理，包括直接伤害和位移伤害机理，推导了冲击波肺伤害死亡半径，头部和身体撞击死亡半径耳鼓膜破裂半径公式；讨论了火球热辐射伤害效应，推导了其伤害半径公式；讨论了房屋倒塌的伤害效应，介绍了其死亡人数的估计方法。     

井下运输系统环境状况的灰色聚类分析

根据煤矿生产实际，应用灰色系统理论建立了井下劳动环境聚类指标体系，按照安全人机工５程学的观点，从人生理对劳动环境的适应程序出了，确定了不同劳动环境灰类的灰数给出了不同灰类的白化函数，标定了灰色聚类权，并计算出聚类系数，针对矿井不同运输子系统，进行了灰色聚类分析，确定出不同运输子系统的劳动环境状况，以便进一步改善井下作业环境，减少或杜绝事故的发生。     

催化剂Pd/CeO_2中Pd与CeO_2之间的SMSI对汽车尾气的催化活性的影响

在汽车尾气模拟配气的条件下 ,用XRD和CO吸附技术研究了催化剂Pd/CeO2 中的Pd与CeO2 之间的SMSI对尾气的催化活性。结果发现高温还原能在催化剂Pd/CeO2 上形成SMSI ,并且这种强相互作用能够显著地提高催化剂对尾气的催化活性     

多点起爆炸药形成平面波数值模拟分析

为了获得体积小,平面性好的炸药平面波发生器,设计了4点起爆薄层炸药形成平面波的物理模型,用非线性有限元方法对平面波形成过程进行了数值模拟,得到了不同时刻的波形图像,输出平面波波形时间差小于0.05μs.研究结果可为多点起爆炸药平面波发生器的设计提供依据.