目的探讨Med-Logics0、-10和-20刀片制作准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)角膜瓣的特点。方法入选近视患者共210例(420眼)行LASIK,按所应用刀片的不同,分为0、-10和-20刀片组,每组各70例(140眼)。术后7d,...目的探讨Med-Logics0、-10和-20刀片制作准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)角膜瓣的特点。方法入选近视患者共210例(420眼)行LASIK,按所应用刀片的不同,分为0、-10和-20刀片组,每组各70例(140眼)。术后7d,应用OCT分别测量每个角膜上0°、90°两条经线所在截面上特定7个点的角膜瓣厚度,并对每个角膜瓣上14个测量点的角膜瓣厚度进行对比分析。采用独立样本t检验、单因素方差分析对数据进行统计学处理。结果 0、-10和-20刀片组中央角膜瓣厚度均值分别为(134.0±14.0)μm、(113.5±10.4)μm和(107.9±12.6)μm,0刀片组明显高于-10刀片组和-20刀片组,而-10刀片组和-20刀片组差异没有统计学意义(P>0.05)。三组角膜中央区域和周边区域差异均有统计学意义(均为P<0.005)。三组中制作角膜瓣双眼鼻侧和颞侧角膜瓣厚度比较,各组内差异均有统计学意义(均为P<0.05)。三组中各自角膜上两条经线所在截面的平均角膜瓣厚度差异均无统计学意义(均为P>0.05)。0刀片组中与理论值差值≤15μm者有948个测量点(48.4%);-10刀片组中与理论值差值≤15μm者有1118个测量点(57.0%);-20刀片组中与理论值差值≤15μm者有1020个测量点(52.0%)。结论 110Moria微型角膜刀应用常规0刀片、-10和-20刀片角膜瓣,重现性较好,-10刀片和-20刀片相比角膜瓣中央区角膜瓣厚度和全角膜平均厚度无明显差异,三组角膜瓣的厚度值鼻侧和颞侧相比有显著性差异。展开更多
The influences of CeO2-ZrO2 and γ-Al2O3 mixing methods on the catalytic activity and stability of partial oxidation of methane （POM） were investigated over Ni/Ce0.7Zr0.3O2-Al2O3 catalysts. The catalysts were charac...The influences of CeO2-ZrO2 and γ-Al2O3 mixing methods on the catalytic activity and stability of partial oxidation of methane （POM） were investigated over Ni/Ce0.7Zr0.3O2-Al2O3 catalysts. The catalysts were characterized by XRD, TPR, H2-chemsorption, and TG-DTA. For fresh catalysts, the results showed that the salt precursor mixing catalyst （ATOM） presented better performance than the catalysts prepared by the precipitator mixing method （MOL） and the powder mechanically mixing method （MECH）. The result of XRD suggested that the interaction between CeO2-ZrO2 and Al2O3 in ATOM sample was stronger than the others, which led to more lattice defects and thereby better initial activity. Moreover, the MECH sample had the best stability and the least coke deposition in 24 h stability tests. The results of TPR and H2-chemsorption indicated that the intimate contact of Ni-Al in MECH sample enhanced the ability of resisting coke deposition and metal sintering.展开更多
The effect of the mixing ways of Ce0.7Zr0.3O2-Al2O3 mixed oxides on the partial oxidations of methane （POM） was investigated over Pd/Ce0.7Zr0.3O2-Al2O3 catalysts, the mixing ways including salt precursor mixing （A...The effect of the mixing ways of Ce0.7Zr0.3O2-Al2O3 mixed oxides on the partial oxidations of methane （POM） was investigated over Pd/Ce0.7Zr0.3O2-Al2O3 catalysts, the mixing ways including salt precursor mixing （ATOM）, precipitator mixing （MOL）, and powder mechanically mixing （MECH）, respectively. The test results indicated that among the three samples, Pd/ATOM had the best catalytic activity while Pd/MOL had the best stability in the stability test. Both the activity sequences of the fresh and used samples were consistent with the order of Pd dispersion. According to the X-ray diffraction （XRD） and BET characterization, the interaction of Ce^4＋, Zr^4＋, and Al^3＋ in the ATOM mixed oxide was in favor of performing higher catalytic activity and thermal stability. The stability test indicated that Pd/MOL had the highest Pd dispersion and least coke formation on the active sites calculated by the Hz-chemisorption and TG results, which was considered to relate to its superior activity of POM to other catalysts.展开更多
基金973 Program (2004CB719503)Key Program of Natural Science Foundation of Tianjin (07JCZDJC01600)Program for New Century Excellent Talents in University (NCET-06-0243)
文摘The influences of CeO2-ZrO2 and γ-Al2O3 mixing methods on the catalytic activity and stability of partial oxidation of methane （POM） were investigated over Ni/Ce0.7Zr0.3O2-Al2O3 catalysts. The catalysts were characterized by XRD, TPR, H2-chemsorption, and TG-DTA. For fresh catalysts, the results showed that the salt precursor mixing catalyst （ATOM） presented better performance than the catalysts prepared by the precipitator mixing method （MOL） and the powder mechanically mixing method （MECH）. The result of XRD suggested that the interaction between CeO2-ZrO2 and Al2O3 in ATOM sample was stronger than the others, which led to more lattice defects and thereby better initial activity. Moreover, the MECH sample had the best stability and the least coke deposition in 24 h stability tests. The results of TPR and H2-chemsorption indicated that the intimate contact of Ni-Al in MECH sample enhanced the ability of resisting coke deposition and metal sintering.
基金973 Program (2004CB719503)Key Program of Natural Science Foundation of Tianjin (07JCZDJC01600)Program for New Century Excellent Talents in University (NCET-06-0243)
文摘The effect of the mixing ways of Ce0.7Zr0.3O2-Al2O3 mixed oxides on the partial oxidations of methane （POM） was investigated over Pd/Ce0.7Zr0.3O2-Al2O3 catalysts, the mixing ways including salt precursor mixing （ATOM）, precipitator mixing （MOL）, and powder mechanically mixing （MECH）, respectively. The test results indicated that among the three samples, Pd/ATOM had the best catalytic activity while Pd/MOL had the best stability in the stability test. Both the activity sequences of the fresh and used samples were consistent with the order of Pd dispersion. According to the X-ray diffraction （XRD） and BET characterization, the interaction of Ce^4＋, Zr^4＋, and Al^3＋ in the ATOM mixed oxide was in favor of performing higher catalytic activity and thermal stability. The stability test indicated that Pd/MOL had the highest Pd dispersion and least coke formation on the active sites calculated by the Hz-chemisorption and TG results, which was considered to relate to its superior activity of POM to other catalysts.
