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A series of CdS with various shapes of microsphere, flower-like and leaf-like were templatefreely synthesized by a hydrothermal method. Powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and UV-vis absorption spectroscopy (UV-vis) were applied to characterize the morphology, optical and other physical properties of the as-prepared CdS. An optical spectrum analyzer was used to measure the wavelength of the illuminant on the slurry in the activity evaluations of photocatalytic reduction of CO2 over CdS. Both sources of cadmium and sulfur had great impact on the CdS morphology as can be seen in the SEM images. By means of a series of activity evaluations, the microspheric CdS made from cadmium nitrate and thioacetamide showed better photocatalytic activity for the reduction of CO2 to methyl formate (MF) in methanol than the flower-like and leaf-like CdS catalysts. 相似文献
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Photocatalytic reduction of CO2 was carried out on villiform spherical catalysts of Pd-TiO2 in isopropanol solution. The catalysts were synthesized by hydrothermal method, their structures, morphologies and optical absorption properties were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis absorption spectroscopy (UV-vis). The photocatalytic activities with different loading amounts and morphologies were evaluated for determining the dominant effect and optimizing the catalyst preparation. Based on a villiform spherical TiO2 with the largest specific surface area in our experiments, we prepared a set of catalysts with various loading amounts of palladium and tested them by bubbling CO2 through the slurry of catalyst and isopropanol. The highest formation rate of isopropyl formate was 276.6 μmol/g·cat/h. Eventually we proposed the reaction mechanism. 相似文献
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在间歇操作的淤浆床反应器中,以TiO2为催化剂,考察了溶液pH值和温度对4BS染料的吸附和光催化降解的影响。结果表明,吸附平衡受溶液的pH值和温度的影响,酸性和较高温度有利于4BS染料吸附,并可用Langmuir等温吸附方程加以描述。在pH值为3.6,25℃和催化剂用量为2.0g/L条件下,4BS染料的降解效果较好。在实验研究的基础上得到了消除固液混合和外扩散影响的反应动力学方程。 相似文献
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含磁性γ-Fe2O3核的TiO2/Al2O3催化剂的制备及光催化性能 总被引:7,自引:2,他引:5
TiO2作为光催化剂,可有效地用于水处理,但存在催化剂如何回收再利用和反应器怎样放大设计的问题。该文提出了含磁性核的TiO2催化剂的合成方法,并对典型污染物的降解作了动力学研究,力求解决此类问题。首先,采用共沉法和溶胶-凝胶法制得磁载光催化剂TiO2/A l2O3/γ-Fe2O3,并对该催化剂分别用TEM和XRD进行了形貌和晶相表征。随后,研究了该催化剂对可溶性染料中间体对硝基甲苯邻磺酸(NTS)和直接耐酸大红染料(4BS)的光催化降解性能。结果表明:该催化剂在水溶液中具有良好的分散效果和较高的催化活性,以250 W高压汞灯为光源,经1.5 h的光催化降解,染料去除率可达90%以上;在外加磁场的作用下,催化剂可与液相迅速分离。经实验数据处理,发现NTS在该催化剂上的光催化降解过程符合零级反应动力学模型。 相似文献
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本文针对无菌熔接片的加热升温过程进行数值模拟分析,具体考察了熔接片基片材质、所施加电压以及电阻线电导率等三个参数对其加热升温过程的影响结果表明,在所考察的镍、铜和不锈钢三种基片中铜为综合性能较好的材料:此外,所施加电压与电阻线的电导率对熔接片的升温加热过程也有明显影响。本文的研究结果能为无菌熔接片的优化设计提供一定的指导作用,进而促进开放式医用导管无菌熔接技术与装备的发展。 相似文献
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为了对轮式移动机器人(WMR)进行光滑、鲁棒、稳定的轨迹跟踪控制,分析了生物激励神经动力学原理,研究了非线性模型预测控制策略,提出了一种基于神经动力学思想的模型预测终端控制方法。首先,针对传统控制方法存在的初始速度跳变问题,利用神经动力学在信息处理方面的优良特性,设计了神经动力学控制模块;然后,根据模型预测控制原理给出了一个优化控制模块;最后,设计了终端域和线性反馈终端控制器来保证系统的全局渐近稳定性。仿真结果表明:利用所设计的控制方法进行曲线跟踪时,被控WMR系统收敛到参考轨迹的时间可从12s降到5s,初始线速度/角速度分别从[-3,4]m/s和[-5,6]rad/s缩小到[0,2]m/s和[-3,3]rad/s,且系统输出有界光滑,使WMR在完成轨迹跟踪的同时实现了全局渐进稳定。由于文中核心算法的推导过程不受WMR运动学模型限制,故该研究结论亦可应用于其他结构的移动机器人。 相似文献
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A series of CdS with various shapes of microsphere, flower-like and leaf-like were templatefreely synthesized by a hydrothermal method. Powder X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET), scanning electron microscopy(SEM) and UV-vis absorption spectroscopy(UV-vis) were applied to characterize the morphology, optical and other physical properties of the as-prepared CdS. An optical spectrum analyzer was used to measure the wavelength of the illuminant on the slurry in the activity evaluations of photocatalytic reduction of CO_2 over CdS. Both sources of cadmium and sulfur had great impact on the CdS morphology as can be seen in the SEM images. By means of a series of activity evaluations, the microspheric CdS made from cadmium nitrate and thioacetamide showed better photocatalytic activity for the reduction of CO_2 to methyl formate(MF) in methanol than the flower-like and leaf-like CdS catalysts. 相似文献