To satisfy the mechanical and biological requirement of porous bone substitutes, porous Ti with two different pore sizes designed in advance was fabricated by the space-holder sintering process. Mechanical properties ...To satisfy the mechanical and biological requirement of porous bone substitutes, porous Ti with two different pore sizes designed in advance was fabricated by the space-holder sintering process. Mechanical properties of the porous Ti were explored via room temperature compressive tests. The pore sizes and shapes are uniform throughout the specimens with porosities ranging from 36% to 63%. The compression strength and the elastic modulus are in the range from 94.05 to 468.57 MPa and 2.662 to 18 GPa, respectively. It is worth noting that the relationship between the compressive strength and the porosities is completely linear relation beyond the effect of pore size distributions on the mechanical properties. The value of the constant C achieved from the Gibson-Ashby model suggests that the pore sizes affect the yield strength of the porous Ti and the values of density exponent （n） for porous Ti with two different pore sizes are higher than 2, which suggests that the deformation mode of the porous Ti with a porosity ranging from 36% to 63% is mainly buckling of the cell struts.展开更多
Extractive distillation was investigated for separation of the minimum azeotrope of n-propanol/water, via the Aspen Plus simulation platform. Experimental data of n-propanol/water, which could pass the thermodynamic c...Extractive distillation was investigated for separation of the minimum azeotrope of n-propanol/water, via the Aspen Plus simulation platform. Experimental data of n-propanol/water, which could pass the thermodynamic consistency test, were regressed to get suitable binary interaction parameters(BIPs) by the UNIQUAC thermodynamic model. The azeotrope system was heterogeneous in the simulation with built-in BIPs, which was contrary to the experimental data. The study focused on the effect of thermodynamic parameters on the prediction of phase behavior, and process design of extractive distillation. N-methyl-2-pyrrolidone(NMP) and ethylene glycol were used as solvents to implement the separation. Processes with built-in and regressed BIPs were explored,based on the minimum total annual cost(TAC). There were significant differences in the phase behavior simulation using different thermodynamic parameters, which showed the importance of BIPs in the design and optimization of extractive distillation.展开更多
Compared to the traditional lumped-parameter model, computational fluid dynamics （CFD） attracted more attentions due to facilitating more accurate reactor design and optimization methods when analyzing the heat tran...Compared to the traditional lumped-parameter model, computational fluid dynamics （CFD） attracted more attentions due to facilitating more accurate reactor design and optimization methods when analyzing the heat transfer in the industrial packed bed. Here, a model was developed based on the CFD theory, in which the heterogeneous fluid flow was resolved by considering the oscillatory behavior of voidage and the effective fluid viscosity. The energy transports in packed bed were calculated by the convection and diffusion incorporated with gaseous dispersion in fluid and the contacting thermal conductivity of packed particles in solids. The heat transfer coefficient between fluid and wall was evaluated by considering the turbulence due to the packed particles adjacent to the wall. Thus, the heat transfer in padded bed can be predicted without using any adjustable semi-empirical effective thermal conductivity coefficient. The experimental results from the literature were employed to validate this model.展开更多
Objective： To assess the medical community＇s awareness and practice regarding delirium in the intensive care unit （ICU）. Methods： One hundred and ten predesigned questionnaires were distributed to ICU practition...Objective： To assess the medical community＇s awareness and practice regarding delirium in the intensive care unit （ICU）. Methods： One hundred and ten predesigned questionnaires were distributed to ICU practitioners in the affiliated hospitals of Zhejiang University. Results： A total of 105 valid questionnaires were collected. Totally, 55.3% of the clinicians considered that delirium was common in the ICU. Delirium was believed to be a significant or serious problem by 70.5% of respondents, and under-diagnosis was acknowledged by 56.2% of the respondents. The incidence of ICU delirium is even more under-estimated by the pediatric doctors compared with their counterparts in adult ICU （P〈0.05）. Primary disease of the brain （agreed by 82.1% of the respondents） was believed to be the most common risk factor for delirium. None of the ICU professionals screened delirium or used a specific tool for delirium assessment routinely. The vast majority （92.4%） of respondents had little knowledge on the diagnosis and the standard treatment of delirium. Conclusions： Although delirium is considered as a serious problem by a majority of the surveyed ICU professionals, it is still under-recognized in routine critical care practice. Data from this survey show a disconnection between the perceived significance of delirium and the current practices of monitoring and treatment in ICU in China.展开更多
基金Project （2012CB619100） supported by the National Basic Research Program of China
文摘To satisfy the mechanical and biological requirement of porous bone substitutes, porous Ti with two different pore sizes designed in advance was fabricated by the space-holder sintering process. Mechanical properties of the porous Ti were explored via room temperature compressive tests. The pore sizes and shapes are uniform throughout the specimens with porosities ranging from 36% to 63%. The compression strength and the elastic modulus are in the range from 94.05 to 468.57 MPa and 2.662 to 18 GPa, respectively. It is worth noting that the relationship between the compressive strength and the porosities is completely linear relation beyond the effect of pore size distributions on the mechanical properties. The value of the constant C achieved from the Gibson-Ashby model suggests that the pore sizes affect the yield strength of the porous Ti and the values of density exponent （n） for porous Ti with two different pore sizes are higher than 2, which suggests that the deformation mode of the porous Ti with a porosity ranging from 36% to 63% is mainly buckling of the cell struts.
基金Supported by the National Natural Science Foundation of China(21676152)the Key Research Project of Shandong Province(2016GSF116004)
文摘Extractive distillation was investigated for separation of the minimum azeotrope of n-propanol/water, via the Aspen Plus simulation platform. Experimental data of n-propanol/water, which could pass the thermodynamic consistency test, were regressed to get suitable binary interaction parameters(BIPs) by the UNIQUAC thermodynamic model. The azeotrope system was heterogeneous in the simulation with built-in BIPs, which was contrary to the experimental data. The study focused on the effect of thermodynamic parameters on the prediction of phase behavior, and process design of extractive distillation. N-methyl-2-pyrrolidone(NMP) and ethylene glycol were used as solvents to implement the separation. Processes with built-in and regressed BIPs were explored,based on the minimum total annual cost(TAC). There were significant differences in the phase behavior simulation using different thermodynamic parameters, which showed the importance of BIPs in the design and optimization of extractive distillation.
基金Supported by National Natural Science Foundation of China(21676266,21676269)the "Strategic Priority Research Program" of the Chinese Academy of Sciences(XDB17020100)the National Key Projects for Fundamental Research and Development of China(2016YFA0202801)
文摘Compared to the traditional lumped-parameter model, computational fluid dynamics （CFD） attracted more attentions due to facilitating more accurate reactor design and optimization methods when analyzing the heat transfer in the industrial packed bed. Here, a model was developed based on the CFD theory, in which the heterogeneous fluid flow was resolved by considering the oscillatory behavior of voidage and the effective fluid viscosity. The energy transports in packed bed were calculated by the convection and diffusion incorporated with gaseous dispersion in fluid and the contacting thermal conductivity of packed particles in solids. The heat transfer coefficient between fluid and wall was evaluated by considering the turbulence due to the packed particles adjacent to the wall. Thus, the heat transfer in padded bed can be predicted without using any adjustable semi-empirical effective thermal conductivity coefficient. The experimental results from the literature were employed to validate this model.
文摘Objective： To assess the medical community＇s awareness and practice regarding delirium in the intensive care unit （ICU）. Methods： One hundred and ten predesigned questionnaires were distributed to ICU practitioners in the affiliated hospitals of Zhejiang University. Results： A total of 105 valid questionnaires were collected. Totally, 55.3% of the clinicians considered that delirium was common in the ICU. Delirium was believed to be a significant or serious problem by 70.5% of respondents, and under-diagnosis was acknowledged by 56.2% of the respondents. The incidence of ICU delirium is even more under-estimated by the pediatric doctors compared with their counterparts in adult ICU （P〈0.05）. Primary disease of the brain （agreed by 82.1% of the respondents） was believed to be the most common risk factor for delirium. None of the ICU professionals screened delirium or used a specific tool for delirium assessment routinely. The vast majority （92.4%） of respondents had little knowledge on the diagnosis and the standard treatment of delirium. Conclusions： Although delirium is considered as a serious problem by a majority of the surveyed ICU professionals, it is still under-recognized in routine critical care practice. Data from this survey show a disconnection between the perceived significance of delirium and the current practices of monitoring and treatment in ICU in China.
