The computational fluid dynamics(CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hydrotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were a...The computational fluid dynamics(CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hydrotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were added to the model by user-defined function(UDF), showing the distribution of temperature and content of sulfides, nitrides, bicyclic aromatics and monocyclic aromatics in different parts of the reaction bed. When the pressure was 6.5 MPa, the amount of mixing hydrogen was 0.84%(m), the space velocity was 2 h-1 and the inlet temperature was 633 K, the temperature reached a maximum at a height of 0.15 m, and the range of radial temperature reached its maximum(2.5 K) at a height of 0.15 m. It indicated that the proper ratio of height to diameter of catalyst bed in the tubular reactor was 5-6. The increase of inlet temperature, the mixing hydrogen and the decrease of space velocity led to the decrease in the content of bicyclic aromatics, sulfides and nitrides, and the increase in monocyclic aromatics content, while the high temperature increased. The results were in good agreement with experimental data, indicating to the high accuracy of the model.展开更多
目的探讨胃炎评价(operative link on gastritis assessment,OLGA)系统及基于肠化的胃炎评价(operative link on gastritis assessment based on intestinal metaplasia,OLGIM)系统对慢性萎缩性胃炎患者发生癌变的风险预测价值,以及可...目的探讨胃炎评价(operative link on gastritis assessment,OLGA)系统及基于肠化的胃炎评价(operative link on gastritis assessment based on intestinal metaplasia,OLGIM)系统对慢性萎缩性胃炎患者发生癌变的风险预测价值,以及可能的其他胃癌相关危险因素。方法回顾性分析2016年7月-2018年11月在南方医科大学深圳医院经内镜结合病理确诊慢性萎缩性胃炎或肠化的643例患者资料。标准胃镜检查评估有无萎缩及其范围,病理证实并评估萎缩、肠化严重程度,以及有无上皮内瘤变。采用OLGA及OLGIM系统进行萎缩和肠化分期,比较OLGA和OLGIM低分级与高分级患者高级别上皮内瘤变(high-grade intraepithelial neoplasia,HGIN)检出率。结果 OLGA高分级患者HGIN检出率(13.89%,10/72)显著高于低分级患者(3.85%,22/571,χ2=13.618,P<0.001);OLGIM高分级患者HGIN检出率(13.41%,11/82)显著高于低分级患者(3.74%,21/561,χ2=14.150,P<0.001);OLGA与OLGIM均为高分级患者,HGIN检出率进一步升高[21.21%(7/33)比4.10%(25/610),χ2=19.389,P<0.001]。Logistic回归分析显示,OLGA、OLGIM高分级患者发生HGIN的危险度是低分级患者的2.640倍(95%CI:1.083~6.439,P=0.033)及2.747倍(95%CI:1.156~6.528,P=0.022),OLGA与OLGIM均为高分级患者,比值比为6.300(95%CI:2.497~15.897,P<0.001)。结论 OLGA与OLGIM系统对慢性萎缩性胃炎有较好的癌变风险预测价值,是患者进行胃镜精查和制定随访策略的重要参考依据。展开更多
文摘The computational fluid dynamics(CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hydrotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were added to the model by user-defined function(UDF), showing the distribution of temperature and content of sulfides, nitrides, bicyclic aromatics and monocyclic aromatics in different parts of the reaction bed. When the pressure was 6.5 MPa, the amount of mixing hydrogen was 0.84%(m), the space velocity was 2 h-1 and the inlet temperature was 633 K, the temperature reached a maximum at a height of 0.15 m, and the range of radial temperature reached its maximum(2.5 K) at a height of 0.15 m. It indicated that the proper ratio of height to diameter of catalyst bed in the tubular reactor was 5-6. The increase of inlet temperature, the mixing hydrogen and the decrease of space velocity led to the decrease in the content of bicyclic aromatics, sulfides and nitrides, and the increase in monocyclic aromatics content, while the high temperature increased. The results were in good agreement with experimental data, indicating to the high accuracy of the model.
文摘目的探讨胃炎评价(operative link on gastritis assessment,OLGA)系统及基于肠化的胃炎评价(operative link on gastritis assessment based on intestinal metaplasia,OLGIM)系统对慢性萎缩性胃炎患者发生癌变的风险预测价值,以及可能的其他胃癌相关危险因素。方法回顾性分析2016年7月-2018年11月在南方医科大学深圳医院经内镜结合病理确诊慢性萎缩性胃炎或肠化的643例患者资料。标准胃镜检查评估有无萎缩及其范围,病理证实并评估萎缩、肠化严重程度,以及有无上皮内瘤变。采用OLGA及OLGIM系统进行萎缩和肠化分期,比较OLGA和OLGIM低分级与高分级患者高级别上皮内瘤变(high-grade intraepithelial neoplasia,HGIN)检出率。结果 OLGA高分级患者HGIN检出率(13.89%,10/72)显著高于低分级患者(3.85%,22/571,χ2=13.618,P<0.001);OLGIM高分级患者HGIN检出率(13.41%,11/82)显著高于低分级患者(3.74%,21/561,χ2=14.150,P<0.001);OLGA与OLGIM均为高分级患者,HGIN检出率进一步升高[21.21%(7/33)比4.10%(25/610),χ2=19.389,P<0.001]。Logistic回归分析显示,OLGA、OLGIM高分级患者发生HGIN的危险度是低分级患者的2.640倍(95%CI:1.083~6.439,P=0.033)及2.747倍(95%CI:1.156~6.528,P=0.022),OLGA与OLGIM均为高分级患者,比值比为6.300(95%CI:2.497~15.897,P<0.001)。结论 OLGA与OLGIM系统对慢性萎缩性胃炎有较好的癌变风险预测价值,是患者进行胃镜精查和制定随访策略的重要参考依据。
