目的基于当前版本华西肠癌数据库(Database from Colorectal Cancer,DACCA)分析2007–2022年期间结直肠癌(colorectal cancer,CRC)患者的分布情况及其预后差异和特征,为临床决策提供一定的依据。方法根据制定的筛选条件,从截至2022年6...目的基于当前版本华西肠癌数据库(Database from Colorectal Cancer,DACCA)分析2007–2022年期间结直肠癌(colorectal cancer,CRC)患者的分布情况及其预后差异和特征,为临床决策提供一定的依据。方法根据制定的筛选条件,从截至2022年6月23日更新的DACCA中收集符合研究条件的CRC患者。分析不同常住地CRC患者的分布情况以及生存情况。常住地根据四川省内18个地级市和3个自治州[简称“21市(州)”]进行划分。结果本研究汇集了2007–2022年期间共5416例符合筛选标准的数据。其中CRC患者来源集中在前3位的是成都市(44.77%)、眉山市(5.78%)和南充市(4.56%)。根据CRC患者来源地的叠加趋势热力图分析结果显示,患者基本上按照“绵阳市—成都市—雅安市”为轴线划分出东、西两个区域,大多数患者(5359例,98.95%)分布在东部区域,西部区域分布较少(57例,1.05%);东部区域患者分布较为集中(尤其是成都市),而西部区域患者则呈零星散发分布,且西部区域患者数量增加缓慢且无聚集现象。DACCA中整体CRC患者的1、3和5年累积总生存率分别为96.2%、89.7%和85.1%。多因素Cox比例风险回归模型分析结果显示,性别为男性、年龄为中和老年组(≥35岁)、肿瘤性质为腺癌(相对于黏液腺癌)、分化程度为低分化、pTNM分期为Ⅲ和Ⅳ期、有梗阻和穿孔是CRC患者中位总生存期缩短的危险因素(均P<0.05)。Kaplan-Meier法绘制的CRC生存曲线显示,21市(州)中除内江市的CRC患者总生存情况差于整体CRC患者(P<0.05)外,其余20市(州)的CRC患者总生存情况与整体CRC患者相比差异无统计学意义(P>0.05)。结论基于DACCA中2007–2022年期间的数据分析显示,东部区域集中了大部分CRC患者,其中成都市高度聚集,而西部区域呈零星分布且无聚集现象。现有数据经统计分析仅发现内江市的CRC患者的累积总生存情况差于整体CRC患者外,其他市(州)的CRC患者�展开更多
Aiming at the problem that the existence of inclusions in the tundish continuous casting process can easily lead to quality defects of the slab,the stainless steel continuous casting tundish was taken as the research ...Aiming at the problem that the existence of inclusions in the tundish continuous casting process can easily lead to quality defects of the slab,the stainless steel continuous casting tundish was taken as the research object.The effects of flow control device,inclusion density and inclusion size on the mixing characteristics of molten steel and inclusion behavior in tundish were studied.The results showed that compared with the tundish without flow control device,the average residence time of molten steel was prolonged by about 49 s,the dead zone volume fraction was reduced by 8.93%,and the piston fluid integral rate was increased by 12.68%.In the turbulence inhibitor(TI)tundish with weir-dam combination,the removal rate of inclusions with a density of 2700 kg m^(-3) and a particle size of 5 lm is 63.32%,while the removal rate of large inclusions with a density of 150μm could reach 89.04%.When the inclusion particle size was 10-50μm and the density was 2700-4500 kg m^(-3),the effect of inclusion density on inclusion removal rate was small.At the same time,when weir-dam combination TI tundish was set,the inclusions were mainly limited to the slag-metal interface of the first and second chambers of the tundish.The removal rate of inclusions in the first chamber was generally improved,with 10μm inclusions accounting for 47.67% and 150μm inclusions accounting for 60.69%.Furthermore,it has the best effect on the removal of small-size inclusions,especially those less than 70μm.展开更多
A bended ribbon biomass particle model was developed to explore the dynamic transport properties inside a riser reactor.Residence time distribution(RTD)of the particles was analyzed by using the Eulerian-Lagrange meth...A bended ribbon biomass particle model was developed to explore the dynamic transport properties inside a riser reactor.Residence time distribution(RTD)of the particles was analyzed by using the Eulerian-Lagrange method.The effects of sampling height,particle density,particle size and gas-to-solid mass ratio on RTD were investigated.The coupled Computational Fluid Dynamics and Discrete Element Method(CFD-DEM)model was verified firstly by experimental data on pressure drop and residence time distribution density function.The simulation results demonstrated that the ribbon biomass particles display a typical annular-core spatial distribution during transportation.The RTD of particles exhibit an approximate single-peaked normal distribution.The mean residence time(MRT)can reach up to 0.7 s when the particle density is 1200 kg/m^(3).Particle with higher density has longer mean residence time.The flow patterns are closer to plug flow if particle length over 12 mm.The particle flow pattern is not sensitive to changes in particle density and size,while the gas-to-material mass ratio has a significant impact on it.展开更多
In continuous biomass torrefaction plants,the products'yields,composition and homogeneity highly depend on the residence time of particles.A characterization of particle residence time distribution(RTD)was therefo...In continuous biomass torrefaction plants,the products'yields,composition and homogeneity highly depend on the residence time of particles.A characterization of particle residence time distribution(RTD)was therefore carried out in an industrial-scale multiple hearth furnace on poplar wood chips using radio frequency identification tracers.The effects of operating conditions,namely,mass flow rate of biomass,shaft speed of the rabbling system and interdental length on the RTD were studied.The increase of shaft speed and mass flow rate reduces particles’mean residence time.Lowering the length between two successive teeth also increases the bed speed.Uncontrollable biomass accumulation(also called“bulldozing”)was observed during several tests.This phenomenon is favored by a high mass flow rate of resources,a small interdental length between the teeth and a low shaft speed.RTD measurements were compared to the axial dispersion model.For all tests,the Peclet number is ranging between 20 and 62,indicating that the multiple hearth furnace cannot be modelled as an ideal plug flow reactor.展开更多
The particle residence time distribution(RTD)and axial dispersion coefficient are key parameters for the design and operation of a pressurized circulating fluidized bed(PCFB).In this study,the effects of pressure(0.1-...The particle residence time distribution(RTD)and axial dispersion coefficient are key parameters for the design and operation of a pressurized circulating fluidized bed(PCFB).In this study,the effects of pressure(0.1-0.6 MPa),fluidizing gas velocity(2-7 m·s^(-1)),and solid circulation rate(10-90 kg·m^(-2)·s^(-1))on particle RTD and axial dispersion coefficient in a PCFB are numerically investigated based on the multiphase particle-in-cell(MP-PIC)method.The details of the gas-solid flow behaviors of PCFB are revealed.Based on the gas-solid flow pattern,the particles tend to move more orderly under elevated pressures.With an increase in either fluidizing gas velocity or solid circulation rate,the mean residence time of particles decreases while the axial dispersion coefficient increases.With an increase in pressure,the core-annulus flow is strengthened,which leads to a wider shape of the particle RTD curve and a larger mean particle residence time.The back-mixing of particles increases with increasing pressure,resulting in an increase in the axial dispersion coefficient.展开更多
Understanding the residence time distribution(RTD)of a continuous hydrothermal reactor is of great significance to improve product quality and reaction efficiency.In this work,an on-line measurement system is attached...Understanding the residence time distribution(RTD)of a continuous hydrothermal reactor is of great significance to improve product quality and reaction efficiency.In this work,an on-line measurement system is attached to a continuous reactor to investigate the characteristics of RTD.An approach that can accurately fit and describe the experimental measured RTD curve by finding characteristic values is proposed for analysis and comparison.The RTD curves of three experiment groups are measured and the characteristic values are calculated.Results show that increasing total flow rate and extending effective reactor length have inverse effect on average residence time,but they both cause the reactor to approach a plug flow reactor and improve the materials leading.The branch flow rate fraction has no significant effect on RTD characteristics in the scope of the present work except the weak negative correlation with the average residence time.Besides,the natural convection stirring effect can also increase the average residence time,especially when the forced flow is weak.The analysis reveals that it is necessary to consider the matching of natural convection,forced flow and reactor size to control RTD when designing the hydrothermal reactor and working conditions.展开更多
A millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by...A millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by means of contraction and expansion of the reaction channel. The liquid holdup was greatly increased through connection of multiple mixing units. Structure optimization of the reactor was carried out by computational fluid dynamics simulation, from which the effect of reactor internals on mixing and the influence of parallel branching structure on heat transfer were discussed. The UV–vis absorption spectroscopy was used to determine the residence time distribution in the reactor, and characteristic parameters such as skewness and dimensionless variance were obtained. Further, a chained stagnant flow model was proposed to precisely describe the trailing phenomenon caused by fluid stagnation and laminar flow in small scale reactors, which enables a better fit for the experimental results of the asymmetric residence time distribution. In addition, the heat transfer performance of the reactor was investigated, and the overall heat transfer coefficient was 110–600 W m^(-2)K-1in the flow rate range of 10–40 m L/min.展开更多
文摘目的基于当前版本华西肠癌数据库(Database from Colorectal Cancer,DACCA)分析2007–2022年期间结直肠癌(colorectal cancer,CRC)患者的分布情况及其预后差异和特征,为临床决策提供一定的依据。方法根据制定的筛选条件,从截至2022年6月23日更新的DACCA中收集符合研究条件的CRC患者。分析不同常住地CRC患者的分布情况以及生存情况。常住地根据四川省内18个地级市和3个自治州[简称“21市(州)”]进行划分。结果本研究汇集了2007–2022年期间共5416例符合筛选标准的数据。其中CRC患者来源集中在前3位的是成都市(44.77%)、眉山市(5.78%)和南充市(4.56%)。根据CRC患者来源地的叠加趋势热力图分析结果显示,患者基本上按照“绵阳市—成都市—雅安市”为轴线划分出东、西两个区域,大多数患者(5359例,98.95%)分布在东部区域,西部区域分布较少(57例,1.05%);东部区域患者分布较为集中(尤其是成都市),而西部区域患者则呈零星散发分布,且西部区域患者数量增加缓慢且无聚集现象。DACCA中整体CRC患者的1、3和5年累积总生存率分别为96.2%、89.7%和85.1%。多因素Cox比例风险回归模型分析结果显示,性别为男性、年龄为中和老年组(≥35岁)、肿瘤性质为腺癌(相对于黏液腺癌)、分化程度为低分化、pTNM分期为Ⅲ和Ⅳ期、有梗阻和穿孔是CRC患者中位总生存期缩短的危险因素(均P<0.05)。Kaplan-Meier法绘制的CRC生存曲线显示,21市(州)中除内江市的CRC患者总生存情况差于整体CRC患者(P<0.05)外,其余20市(州)的CRC患者总生存情况与整体CRC患者相比差异无统计学意义(P>0.05)。结论基于DACCA中2007–2022年期间的数据分析显示,东部区域集中了大部分CRC患者,其中成都市高度聚集,而西部区域呈零星分布且无聚集现象。现有数据经统计分析仅发现内江市的CRC患者的累积总生存情况差于整体CRC患者外,其他市(州)的CRC患者�
基金financially supported by the National Natural Science Foundation of China(Nos.52174321,51874203 and 52074186).
文摘Aiming at the problem that the existence of inclusions in the tundish continuous casting process can easily lead to quality defects of the slab,the stainless steel continuous casting tundish was taken as the research object.The effects of flow control device,inclusion density and inclusion size on the mixing characteristics of molten steel and inclusion behavior in tundish were studied.The results showed that compared with the tundish without flow control device,the average residence time of molten steel was prolonged by about 49 s,the dead zone volume fraction was reduced by 8.93%,and the piston fluid integral rate was increased by 12.68%.In the turbulence inhibitor(TI)tundish with weir-dam combination,the removal rate of inclusions with a density of 2700 kg m^(-3) and a particle size of 5 lm is 63.32%,while the removal rate of large inclusions with a density of 150μm could reach 89.04%.When the inclusion particle size was 10-50μm and the density was 2700-4500 kg m^(-3),the effect of inclusion density on inclusion removal rate was small.At the same time,when weir-dam combination TI tundish was set,the inclusions were mainly limited to the slag-metal interface of the first and second chambers of the tundish.The removal rate of inclusions in the first chamber was generally improved,with 10μm inclusions accounting for 47.67% and 150μm inclusions accounting for 60.69%.Furthermore,it has the best effect on the removal of small-size inclusions,especially those less than 70μm.
基金support of the National Natural Science Foundation of China (grant No.51906092)China Tobacco Jiangxi Industrial Corporation Limited.
文摘A bended ribbon biomass particle model was developed to explore the dynamic transport properties inside a riser reactor.Residence time distribution(RTD)of the particles was analyzed by using the Eulerian-Lagrange method.The effects of sampling height,particle density,particle size and gas-to-solid mass ratio on RTD were investigated.The coupled Computational Fluid Dynamics and Discrete Element Method(CFD-DEM)model was verified firstly by experimental data on pressure drop and residence time distribution density function.The simulation results demonstrated that the ribbon biomass particles display a typical annular-core spatial distribution during transportation.The RTD of particles exhibit an approximate single-peaked normal distribution.The mean residence time(MRT)can reach up to 0.7 s when the particle density is 1200 kg/m^(3).Particle with higher density has longer mean residence time.The flow patterns are closer to plug flow if particle length over 12 mm.The particle flow pattern is not sensitive to changes in particle density and size,while the gas-to-material mass ratio has a significant impact on it.
文摘In continuous biomass torrefaction plants,the products'yields,composition and homogeneity highly depend on the residence time of particles.A characterization of particle residence time distribution(RTD)was therefore carried out in an industrial-scale multiple hearth furnace on poplar wood chips using radio frequency identification tracers.The effects of operating conditions,namely,mass flow rate of biomass,shaft speed of the rabbling system and interdental length on the RTD were studied.The increase of shaft speed and mass flow rate reduces particles’mean residence time.Lowering the length between two successive teeth also increases the bed speed.Uncontrollable biomass accumulation(also called“bulldozing”)was observed during several tests.This phenomenon is favored by a high mass flow rate of resources,a small interdental length between the teeth and a low shaft speed.RTD measurements were compared to the axial dispersion model.For all tests,the Peclet number is ranging between 20 and 62,indicating that the multiple hearth furnace cannot be modelled as an ideal plug flow reactor.
基金Financial support of this work by National Natural Science Foundation of China(51976037)。
文摘The particle residence time distribution(RTD)and axial dispersion coefficient are key parameters for the design and operation of a pressurized circulating fluidized bed(PCFB).In this study,the effects of pressure(0.1-0.6 MPa),fluidizing gas velocity(2-7 m·s^(-1)),and solid circulation rate(10-90 kg·m^(-2)·s^(-1))on particle RTD and axial dispersion coefficient in a PCFB are numerically investigated based on the multiphase particle-in-cell(MP-PIC)method.The details of the gas-solid flow behaviors of PCFB are revealed.Based on the gas-solid flow pattern,the particles tend to move more orderly under elevated pressures.With an increase in either fluidizing gas velocity or solid circulation rate,the mean residence time of particles decreases while the axial dispersion coefficient increases.With an increase in pressure,the core-annulus flow is strengthened,which leads to a wider shape of the particle RTD curve and a larger mean particle residence time.The back-mixing of particles increases with increasing pressure,resulting in an increase in the axial dispersion coefficient.
基金supported by the National Natural Science Foundation of China(52242609)the National Key R&D Program of China(2020YFA0714400)。
文摘Understanding the residence time distribution(RTD)of a continuous hydrothermal reactor is of great significance to improve product quality and reaction efficiency.In this work,an on-line measurement system is attached to a continuous reactor to investigate the characteristics of RTD.An approach that can accurately fit and describe the experimental measured RTD curve by finding characteristic values is proposed for analysis and comparison.The RTD curves of three experiment groups are measured and the characteristic values are calculated.Results show that increasing total flow rate and extending effective reactor length have inverse effect on average residence time,but they both cause the reactor to approach a plug flow reactor and improve the materials leading.The branch flow rate fraction has no significant effect on RTD characteristics in the scope of the present work except the weak negative correlation with the average residence time.Besides,the natural convection stirring effect can also increase the average residence time,especially when the forced flow is weak.The analysis reveals that it is necessary to consider the matching of natural convection,forced flow and reactor size to control RTD when designing the hydrothermal reactor and working conditions.
基金funded by the National Natural Science Foundation of China (Nos. 21991103, 21991104, 22008074, 22008072)Natural Science Foundation of Shanghai (No. 20ZR1415700)China Postdoctoral Science Foundation (Nos. 2020M671025,2019TQ0093)。
文摘A millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by means of contraction and expansion of the reaction channel. The liquid holdup was greatly increased through connection of multiple mixing units. Structure optimization of the reactor was carried out by computational fluid dynamics simulation, from which the effect of reactor internals on mixing and the influence of parallel branching structure on heat transfer were discussed. The UV–vis absorption spectroscopy was used to determine the residence time distribution in the reactor, and characteristic parameters such as skewness and dimensionless variance were obtained. Further, a chained stagnant flow model was proposed to precisely describe the trailing phenomenon caused by fluid stagnation and laminar flow in small scale reactors, which enables a better fit for the experimental results of the asymmetric residence time distribution. In addition, the heat transfer performance of the reactor was investigated, and the overall heat transfer coefficient was 110–600 W m^(-2)K-1in the flow rate range of 10–40 m L/min.
