ZSM-5 zeolite was in-situ synthesized from metakaolin or s alumina sources, respectively. The ZSM-5 zeolite was characterized pinel by incorporating additional silica and by X-ray diffractometry （XRD）, scanning elec...ZSM-5 zeolite was in-situ synthesized from metakaolin or s alumina sources, respectively. The ZSM-5 zeolite was characterized pinel by incorporating additional silica and by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） spectroscopy and N2 adsorption measurement. This supported zeolite was tested on the methanol to propylene （MTP） processes. Experimental results showed that the ZSM-5 zeolite exhibited high selectivity for propylene. The yield of propylene on ZSM-5 zeolite made from metakaolin was increased by 17.73%, while that on ZSM-5 zeolite made from spinel was raised by 9.90%, compared to that achieved with the commercial ZSM-5 zeolite. The significant increase in propylene production is probably due to the distinctive morphology of the ZSM-5 zeolite, which possessed a rough external surface covered with sphere-like particles and distribution of small crystals sized at around 400--500 nm. This morphology could help to generate more crystal defects so that more active centers could be exposed to the reaction mixture. In addition, the zeolite product had a gradient pore distribution and many medium Brǒnsted acid sites, both of which might also contribute to the increased propylene production.展开更多
Dear Editors, Hydrogen is a promising candidate for use in the future as an alternative to traditional petroleum fuels. Electrochemi- cal water splitting is an efficient way to produce hydrogen. It is well known that ...Dear Editors, Hydrogen is a promising candidate for use in the future as an alternative to traditional petroleum fuels. Electrochemi- cal water splitting is an efficient way to produce hydrogen. It is well known that platinum and other precious metals have high HER efficiency. The high cost and scarcity of these precious metals, however, limit their applicability to large-scale hydrogen production. Therefore, considerable attention has been focused recently on exploitation of non-precious catalysts.展开更多
文摘目的分析基于双能量CT影像组学模型术前预测进展期胃腺癌短径≥0.6 cm淋巴结转移(LNM)的价值。方法回顾性分析经手术切除的进展期胃腺癌患者,根据病理结果纳入36例pN3期114枚转移淋巴结(转移组)和26例pN0期65枚非转移淋巴结(非转移组),入组淋巴结短径均≥0.6 cm,将淋巴结分为训练集(n=125)和验证集(n=54)。对比组间原发肿瘤及淋巴结CT特征,采用广义估计方程(GEE)构建临床模型。提取静脉期融合图和碘图中的淋巴结影像组学特征,以组内相关系数(ICC)检验和Boruta算法筛选特征,构建影像组学模型,采用受试者工作特征(ROC)曲线和决策曲线分析(DCA)评价模型的诊断效能和临床收益。结果单因素及多因素GEE分析显示,原发肿瘤部位及最大径、淋巴结边缘及脂肪分数为LNM独立预测因素(P均<0.05),以之构建的临床模型预测训练集和验证集LNM的曲线下面积(AUC)分别为0.74和0.76。经ICC检验(ICC>0.8)及Boruta算法筛选,最终保留27个影像组学特征;以之建立的影像组学模型预测训练集和验证集LNM的AUC分别为0.99和0.98,均高于临床模型(P均<0.01),且临床收益更优。结论基于双能量CT影像组学模型术前预测进展期胃腺癌短径≥0.6 cm LNM具有较高价值。
基金the financial support from National Natural Science Foundation of China(20776124 and 20736011)
文摘ZSM-5 zeolite was in-situ synthesized from metakaolin or s alumina sources, respectively. The ZSM-5 zeolite was characterized pinel by incorporating additional silica and by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） spectroscopy and N2 adsorption measurement. This supported zeolite was tested on the methanol to propylene （MTP） processes. Experimental results showed that the ZSM-5 zeolite exhibited high selectivity for propylene. The yield of propylene on ZSM-5 zeolite made from metakaolin was increased by 17.73%, while that on ZSM-5 zeolite made from spinel was raised by 9.90%, compared to that achieved with the commercial ZSM-5 zeolite. The significant increase in propylene production is probably due to the distinctive morphology of the ZSM-5 zeolite, which possessed a rough external surface covered with sphere-like particles and distribution of small crystals sized at around 400--500 nm. This morphology could help to generate more crystal defects so that more active centers could be exposed to the reaction mixture. In addition, the zeolite product had a gradient pore distribution and many medium Brǒnsted acid sites, both of which might also contribute to the increased propylene production.
基金supported by the National Natural Science Foundation of China(Grant Nos.51272050 and 51572051)the 111 project(Grant No.B13015)of the Ministry Education of China awarded to the Harbin Engineering University
文摘Dear Editors, Hydrogen is a promising candidate for use in the future as an alternative to traditional petroleum fuels. Electrochemi- cal water splitting is an efficient way to produce hydrogen. It is well known that platinum and other precious metals have high HER efficiency. The high cost and scarcity of these precious metals, however, limit their applicability to large-scale hydrogen production. Therefore, considerable attention has been focused recently on exploitation of non-precious catalysts.
