[Objective]The work is devoted to the study of irreversible deformation of artificial samples subjected to a set of standard experiments,with an aim to study their mechanical properties.The principal idea of the study...[Objective]The work is devoted to the study of irreversible deformation of artificial samples subjected to a set of standard experiments,with an aim to study their mechanical properties.The principal idea of the study is related to the preparation of an artificial material with an established constitutive behavior model.The existence of such a well-described material provides future opportunities to conduct controllable experiments on various mechanical processes in rock-like material for further development and validation of theoretical models used in rock mechanics.[Methods]A set of artificial samples was prepared for careful assessment through a number of loading tests.Experimental work was carried out to determine the rheological properties under conditions of triaxial compression tests and uniaxial tension.Triaxial loading tests are completed for 9 samples with varying radial stress levels(0-5 MPa).The samples are loaded up to the yield point with control of radial and volumetric strain.The experimental results,which contain the obtained interrelationships between axial and radial stresses and strains,are analyzed using the Drucker-Prager yield surface.Material hardening is taken into account through the non-associated plastic flow law with the cap model.Numerical modeling of sample loading is performed through the finite difference method.Mathematical model parameters are adjusted to minimize the discrepancy between numerical modeling results and experimental data.The design of a series of experimental studies necessary to determine all the parameters of the model has been studied.[Results]It is shown that the formulated mathematical model allows to reliably reproduce the inelastic behavior of the studied material,and it can be used to solve a set of applied problems in continuum mechanics,the problem of numerical simulation of hydraulic fracture growth in an elastoplastic medium in particular.It was found that for the entire range of applied lateral loads(0-5 MPa),the elastic limit varied from 2 to 4 MPa,after which the material began to behave plastically.It was also determined that at lateral loads≥3 MPa,compaction began to appear in the material beyond the yield point.Judging by the dependence of volumetric strains under a lateral load equal to 1.4 MPa,compaction should begin to appear even at lateral loads lower than 3 MPa.[Conclusion]Taking the plastic behavior of the material into account is necessary when moving on to modeling the hydraulic fracturing process in such a material,and the resultant plasticity parameters for the model material can be used for numerical modeling of elastoplastic deformation of the rock under consideration,including processes such as hydraulic fracture growth in a poroelastoplastic medium.[Significance]The suggested procedure to interpret results of experimental studies can be used for further numerical modeling of mechanical processes in rock masses with inelastic strain accumulation.This opportunity can increase the reliability of geomechanical models used for the optimization of hydrocarbon fields development.展开更多
The research demonstrated that laser powder bed fusion(LPBF)coupled with controlled annealing at 1200°C,could significantly increase the proportion of coincidence site lattice(CSL)grain boundary,thereby achieving...The research demonstrated that laser powder bed fusion(LPBF)coupled with controlled annealing at 1200°C,could significantly increase the proportion of coincidence site lattice(CSL)grain boundary,thereby achieving an outstanding synergy of enhanced strength and exceptional ductility.The plastic deformation behavior,strain hardening behavior,and fracture behavior of LPBF 316L steel annealing at 1200℃for 20 h were studied through quasi-in-situ tensile process.It was found that LPBF 316L steel formed a certain proportion of deformation twins during the tensile process,and the formation of twins changed the crystal orientation,thus promoting further slip and crystal deformation.The synergistic effect of slip and twin promoted higher plasticity.LPBF process coupled with controlled annealing at 1200°C for 20 h leads to a ultimate tensile strength of 613 MPa and total elongation of 73.8%.展开更多
A new dimensionless number is proposed for dynamic plastic deformation analysis of clamped circular plates under underwater explosion loads by introducing dimensional analysis method to the basic dynamical governing e...A new dimensionless number is proposed for dynamic plastic deformation analysis of clamped circular plates under underwater explosion loads by introducing dimensional analysis method to the basic dynamical governing equations of circular plates.The relation between dimensionless final plastic deformation of circular plates and the new dimensionless number is established based on massive underwater explosion test data.Meanwhile,comparative analysis was discussed with two other published dimensionless parameters which indicated the new dimensionless number proposed in this paper is more effective and extensive to predict the dynamic plastic response of circular plates under underwater explosion condition.展开更多
The electric vertical takeoff and landing(e VTOL)aircraft shows great potential for rapid military personnel deployment on the battlefield.However,its susceptibility to control loss,complex crashes,and extremely limit...The electric vertical takeoff and landing(e VTOL)aircraft shows great potential for rapid military personnel deployment on the battlefield.However,its susceptibility to control loss,complex crashes,and extremely limited bottom energy-absorbing space demands higher comprehensive crashworthiness of its subfloor thin-walled structures.This study investigated the energy absorption capacity of novel concave polygonal carbon fiber reinforced plastics(CFRP)tubes under multi-angle collisions.Quasistatic compression experiments and finite element simulations were conducted to assess the failure mode and energy absorption.The influences of cross-section shapes,loading conditions,and geometry parameters on crashworthiness metrics were further analyzed.The results revealed that,under the similar weight,concave polygonal tubes exhibited superior energy absorption under axial loads compared to regular polygonal and circular tubes,attributed to the increased number of axial splits.However,both regular and concave polygonal tubes,particularly the latter,demonstrated reduced oblique energy absorption compared to traditional square tubes with the increasing ratio of SEA value decreased from 20%-16%.Notably,this reduction in energy absorption can be compensated for by the implementation of inward and outward crusher plugs,and with them,the concave polygonal tubes demonstrated outstanding overall crashworthiness performance under multiple loading conditions.This concave cross-sectional design methods could serve as a guidance for the development of the eVTOL subfloor.展开更多
Conventional plasticizers deteriorate mechanical and viscoelastic properties of the propellants due to their migration upon aging and long-term storage,which affects reliability and safety properties during exploitati...Conventional plasticizers deteriorate mechanical and viscoelastic properties of the propellants due to their migration upon aging and long-term storage,which affects reliability and safety properties during exploitation.To address this issue,conventional plasticizer,dioctyl adipate(DOA),is replaced by reactive one,castor oil(CO).In addition,three different types of HTPB were used to obtain propellants with designed viscoelastic and mechanical properties.The CO increased propellants viscosity,without a significant impact on the propellant processability,regardless to the type of prepolymer.Conversely,mechanical properties were different depending on the type of resin,which were further analyzed by gel permeation chromatography(GPC).Addition of CO formed a denser polymer network and shifted T_(g) to higher values,compared to the compositions with DOA.The tensile strength of CO-containing propellants was lower at +20℃ and +50℃ compared to the reference compositions,while the strain at maximum load and strain at break were significantly increased with pronounced plastic deformation,especially for samples at -30℃.The inclusion of CO in the propellants composition gives more room for adjusting a wide range of mechanical properties.展开更多
In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy technology.Physical properties of the alloy,including density,microstructure,melting point,and constant-volu...In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy technology.Physical properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are tested.Via the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1×10^(-3)-5.2×10^(3)s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is obtained.Evolution of the Cu-10Ta microstructure that occurs during high-strain-rate impact is analyzed.Results indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain rate.Under strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less pronounced.Furthermore,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong impact.Analysis reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.展开更多
A method was established for determination of the reducing substances released from plastic blood bags to anticoagulant.The samples were extracted with a solid-phase extraction procedure using dichloromethane as extra...A method was established for determination of the reducing substances released from plastic blood bags to anticoagulant.The samples were extracted with a solid-phase extraction procedure using dichloromethane as extract solvents.The extracts were measured with GC-MS.Several reducing substances,such as 1,2-benzenedicarboxylic acid,alkane and bis(2-ethylhexyl) phthalate,etc were found in anticoagulant.The method was simple and can be used for the quality control of plastic blood bags.展开更多
Brominated flame-retardant,such as deca-BDE,TBBP-A,TBBP-A-bis is one kind of the additives of plastic product for flame retardation.European has published a direction to restrict the used amount of brominated flame-re...Brominated flame-retardant,such as deca-BDE,TBBP-A,TBBP-A-bis is one kind of the additives of plastic product for flame retardation.European has published a direction to restrict the used amount of brominated flame-retardant,because of their toxicity.The present work reports a GC-MS method for the determination of the brominated retardants.The method meets the requirements of the direction 2002/95/EC,and has been applied to the real sample analysis.展开更多
OBJECTIVE Major depressive disorder(MDD) is a common mental illness,which shows serious dysfunction in emotion,motivation and cognition. The imbalance of monoamine neurotransmitter is the classic pathogenesis of depre...OBJECTIVE Major depressive disorder(MDD) is a common mental illness,which shows serious dysfunction in emotion,motivation and cognition. The imbalance of monoamine neurotransmitter is the classic pathogenesis of depression,but more and more evidence indicates that glutamatergic transmission may be the key factor leading to the occurrence of depression. However,the role of the membrane expression and regulation of glutamate receptors in the development of depression has not been elucidated. To address this issue,we have done series of experiments. METHODS Different methods and techniques,such as behavior,morphology,molecular biology and electrophysiology,were applied to investigate the impact of glutamate receptors and their subunits in the regulation of synaptic plasticity and the mechanism in depressive animal models. RESULTS Chronic social defeat stress(CSDS) can induce depressive behaviors in wildtype(WT) mice but not caspase-1 knockout(KO) mice. Further experiments showed that,in WT mice,CSDS induced a significant decrease in the membrane expression levels of the GluR1 and GluR2 subunits of AMPA receptors,the amplitudes of m EPSC in hippocampal CA1,meanwhile the long-term potentiation(LTP) at hippocampus SC-CA1 pathway was also impaired. Oppositely,this CSDS-induced reduction of the membrane expression of AMPA receptors was prevented by the knockout of caspase-1 or caspase-1 inhibitor,in which the expression of GluA1 and GluA2 were upregulated from(60.2±3.4)% and(63.9±3.7)% to(120.1±5.9)%and(112.6±9.6)%,respectively,while the total protein level of AMPA receptor subunits were not affected.On the other hand,a chronic intracerebroventricular injection of IL-1β,a downstream signal molecule of caspase-1,could induce depression-and anxiety-like behaviors in caspase-1 KO mice. CONCLUSION The caspase-1 can mediate the stress-induced depression-like behaviors by down-regulation of the membrane expression of AMPA receptors in hippocampus,the inhibition or knock-out of caspase-1can increase the expression of AMPA receptors in the membrane,thus reversing the depression-like behavior. Caspase-1 may serve as new target for depression therapy.展开更多
To prepare the porous NC-based(nitrocellulose-based) gun propellants,the batch foaming process of using supercritical CO_2 as the physical blowing agent is used.The solubilities of CO_2 in the single-base propellants ...To prepare the porous NC-based(nitrocellulose-based) gun propellants,the batch foaming process of using supercritical CO_2 as the physical blowing agent is used.The solubilities of CO_2 in the single-base propellants and TEGDN(trimethyleneglycol dinitrate) propellants are measured by the gravimetric method,and SEM(scanning electron microscope) is used to observe the morphology of foamed propellants.The result shows that a large amount of CO_2 could be dissolved in NC-based propellants.The experimental results also reveal that the energetic plasticizer TEGDN exerts an important influence on the pore structure.The triaxial tensile failure mechanism for solid-state nucleation is used to explain the nucleation of NC-based propellants in the sol id state.Since some specific foaming behaviors of NC-based propellants can not be explained by the failure mechanism,a solid-state nucleation mechanism which revises the triaxial tensile failure mechanism is proposed and discussed.展开更多
A method was established for qualitative and quantitative determination of the reducing substances from plastic blood bags aqueous extract.The samples were extracted with a solid-phase extraction procedure,dichloromet...A method was established for qualitative and quantitative determination of the reducing substances from plastic blood bags aqueous extract.The samples were extracted with a solid-phase extraction procedure,dichloromethane qua extract solvents,and were measured with GC-MS.With this method,we determined several reducing substances from plastic blood bags aqueous extract and fixed quantify on DEHP (di (2-ethylhexyl) phthalate),one of the dominating reducing substances.The method was simple and can be used for the quality control of plastic blood bags.展开更多
A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical e...A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.展开更多
文摘[Objective]The work is devoted to the study of irreversible deformation of artificial samples subjected to a set of standard experiments,with an aim to study their mechanical properties.The principal idea of the study is related to the preparation of an artificial material with an established constitutive behavior model.The existence of such a well-described material provides future opportunities to conduct controllable experiments on various mechanical processes in rock-like material for further development and validation of theoretical models used in rock mechanics.[Methods]A set of artificial samples was prepared for careful assessment through a number of loading tests.Experimental work was carried out to determine the rheological properties under conditions of triaxial compression tests and uniaxial tension.Triaxial loading tests are completed for 9 samples with varying radial stress levels(0-5 MPa).The samples are loaded up to the yield point with control of radial and volumetric strain.The experimental results,which contain the obtained interrelationships between axial and radial stresses and strains,are analyzed using the Drucker-Prager yield surface.Material hardening is taken into account through the non-associated plastic flow law with the cap model.Numerical modeling of sample loading is performed through the finite difference method.Mathematical model parameters are adjusted to minimize the discrepancy between numerical modeling results and experimental data.The design of a series of experimental studies necessary to determine all the parameters of the model has been studied.[Results]It is shown that the formulated mathematical model allows to reliably reproduce the inelastic behavior of the studied material,and it can be used to solve a set of applied problems in continuum mechanics,the problem of numerical simulation of hydraulic fracture growth in an elastoplastic medium in particular.It was found that for the entire range of applied lateral loads(0-5 MPa),the elastic limit varied from 2 to 4 MPa,after which the material began to behave plastically.It was also determined that at lateral loads≥3 MPa,compaction began to appear in the material beyond the yield point.Judging by the dependence of volumetric strains under a lateral load equal to 1.4 MPa,compaction should begin to appear even at lateral loads lower than 3 MPa.[Conclusion]Taking the plastic behavior of the material into account is necessary when moving on to modeling the hydraulic fracturing process in such a material,and the resultant plasticity parameters for the model material can be used for numerical modeling of elastoplastic deformation of the rock under consideration,including processes such as hydraulic fracture growth in a poroelastoplastic medium.[Significance]The suggested procedure to interpret results of experimental studies can be used for further numerical modeling of mechanical processes in rock masses with inelastic strain accumulation.This opportunity can increase the reliability of geomechanical models used for the optimization of hydrocarbon fields development.
基金Project(52474418)supported by the National Natural Science Foundation of ChinaProject(YDZJSX2022A012)supported by the Central Guiding Local Science and Technology Development Foundation,China。
文摘The research demonstrated that laser powder bed fusion(LPBF)coupled with controlled annealing at 1200°C,could significantly increase the proportion of coincidence site lattice(CSL)grain boundary,thereby achieving an outstanding synergy of enhanced strength and exceptional ductility.The plastic deformation behavior,strain hardening behavior,and fracture behavior of LPBF 316L steel annealing at 1200℃for 20 h were studied through quasi-in-situ tensile process.It was found that LPBF 316L steel formed a certain proportion of deformation twins during the tensile process,and the formation of twins changed the crystal orientation,thus promoting further slip and crystal deformation.The synergistic effect of slip and twin promoted higher plasticity.LPBF process coupled with controlled annealing at 1200°C for 20 h leads to a ultimate tensile strength of 613 MPa and total elongation of 73.8%.
基金supported by the National Natural Science Foundation of China(12402444)。
文摘A new dimensionless number is proposed for dynamic plastic deformation analysis of clamped circular plates under underwater explosion loads by introducing dimensional analysis method to the basic dynamical governing equations of circular plates.The relation between dimensionless final plastic deformation of circular plates and the new dimensionless number is established based on massive underwater explosion test data.Meanwhile,comparative analysis was discussed with two other published dimensionless parameters which indicated the new dimensionless number proposed in this paper is more effective and extensive to predict the dynamic plastic response of circular plates under underwater explosion condition.
基金financially supported by the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.24qnpy041)the Science and Technology Innovation Key R&D Program of Chongqing(Grant No.CSTB2023TIAD-STX0030)。
文摘The electric vertical takeoff and landing(e VTOL)aircraft shows great potential for rapid military personnel deployment on the battlefield.However,its susceptibility to control loss,complex crashes,and extremely limited bottom energy-absorbing space demands higher comprehensive crashworthiness of its subfloor thin-walled structures.This study investigated the energy absorption capacity of novel concave polygonal carbon fiber reinforced plastics(CFRP)tubes under multi-angle collisions.Quasistatic compression experiments and finite element simulations were conducted to assess the failure mode and energy absorption.The influences of cross-section shapes,loading conditions,and geometry parameters on crashworthiness metrics were further analyzed.The results revealed that,under the similar weight,concave polygonal tubes exhibited superior energy absorption under axial loads compared to regular polygonal and circular tubes,attributed to the increased number of axial splits.However,both regular and concave polygonal tubes,particularly the latter,demonstrated reduced oblique energy absorption compared to traditional square tubes with the increasing ratio of SEA value decreased from 20%-16%.Notably,this reduction in energy absorption can be compensated for by the implementation of inward and outward crusher plugs,and with them,the concave polygonal tubes demonstrated outstanding overall crashworthiness performance under multiple loading conditions.This concave cross-sectional design methods could serve as a guidance for the development of the eVTOL subfloor.
基金the support of this research from the Serbian Ministry of Education,Science and Technological Development(Grant No.451-03-68/2023-14/200325)Ministry of Defense(Grant No.VA-TT/1/22-24)。
文摘Conventional plasticizers deteriorate mechanical and viscoelastic properties of the propellants due to their migration upon aging and long-term storage,which affects reliability and safety properties during exploitation.To address this issue,conventional plasticizer,dioctyl adipate(DOA),is replaced by reactive one,castor oil(CO).In addition,three different types of HTPB were used to obtain propellants with designed viscoelastic and mechanical properties.The CO increased propellants viscosity,without a significant impact on the propellant processability,regardless to the type of prepolymer.Conversely,mechanical properties were different depending on the type of resin,which were further analyzed by gel permeation chromatography(GPC).Addition of CO formed a denser polymer network and shifted T_(g) to higher values,compared to the compositions with DOA.The tensile strength of CO-containing propellants was lower at +20℃ and +50℃ compared to the reference compositions,while the strain at maximum load and strain at break were significantly increased with pronounced plastic deformation,especially for samples at -30℃.The inclusion of CO in the propellants composition gives more room for adjusting a wide range of mechanical properties.
文摘In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy technology.Physical properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are tested.Via the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1×10^(-3)-5.2×10^(3)s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is obtained.Evolution of the Cu-10Ta microstructure that occurs during high-strain-rate impact is analyzed.Results indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain rate.Under strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less pronounced.Furthermore,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong impact.Analysis reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.
文摘A method was established for determination of the reducing substances released from plastic blood bags to anticoagulant.The samples were extracted with a solid-phase extraction procedure using dichloromethane as extract solvents.The extracts were measured with GC-MS.Several reducing substances,such as 1,2-benzenedicarboxylic acid,alkane and bis(2-ethylhexyl) phthalate,etc were found in anticoagulant.The method was simple and can be used for the quality control of plastic blood bags.
文摘Brominated flame-retardant,such as deca-BDE,TBBP-A,TBBP-A-bis is one kind of the additives of plastic product for flame retardation.European has published a direction to restrict the used amount of brominated flame-retardant,because of their toxicity.The present work reports a GC-MS method for the determination of the brominated retardants.The method meets the requirements of the direction 2002/95/EC,and has been applied to the real sample analysis.
文摘OBJECTIVE Major depressive disorder(MDD) is a common mental illness,which shows serious dysfunction in emotion,motivation and cognition. The imbalance of monoamine neurotransmitter is the classic pathogenesis of depression,but more and more evidence indicates that glutamatergic transmission may be the key factor leading to the occurrence of depression. However,the role of the membrane expression and regulation of glutamate receptors in the development of depression has not been elucidated. To address this issue,we have done series of experiments. METHODS Different methods and techniques,such as behavior,morphology,molecular biology and electrophysiology,were applied to investigate the impact of glutamate receptors and their subunits in the regulation of synaptic plasticity and the mechanism in depressive animal models. RESULTS Chronic social defeat stress(CSDS) can induce depressive behaviors in wildtype(WT) mice but not caspase-1 knockout(KO) mice. Further experiments showed that,in WT mice,CSDS induced a significant decrease in the membrane expression levels of the GluR1 and GluR2 subunits of AMPA receptors,the amplitudes of m EPSC in hippocampal CA1,meanwhile the long-term potentiation(LTP) at hippocampus SC-CA1 pathway was also impaired. Oppositely,this CSDS-induced reduction of the membrane expression of AMPA receptors was prevented by the knockout of caspase-1 or caspase-1 inhibitor,in which the expression of GluA1 and GluA2 were upregulated from(60.2±3.4)% and(63.9±3.7)% to(120.1±5.9)%and(112.6±9.6)%,respectively,while the total protein level of AMPA receptor subunits were not affected.On the other hand,a chronic intracerebroventricular injection of IL-1β,a downstream signal molecule of caspase-1,could induce depression-and anxiety-like behaviors in caspase-1 KO mice. CONCLUSION The caspase-1 can mediate the stress-induced depression-like behaviors by down-regulation of the membrane expression of AMPA receptors in hippocampus,the inhibition or knock-out of caspase-1can increase the expression of AMPA receptors in the membrane,thus reversing the depression-like behavior. Caspase-1 may serve as new target for depression therapy.
基金funded by the priority academic program development of Jiangsu Higher Education Institutions
文摘To prepare the porous NC-based(nitrocellulose-based) gun propellants,the batch foaming process of using supercritical CO_2 as the physical blowing agent is used.The solubilities of CO_2 in the single-base propellants and TEGDN(trimethyleneglycol dinitrate) propellants are measured by the gravimetric method,and SEM(scanning electron microscope) is used to observe the morphology of foamed propellants.The result shows that a large amount of CO_2 could be dissolved in NC-based propellants.The experimental results also reveal that the energetic plasticizer TEGDN exerts an important influence on the pore structure.The triaxial tensile failure mechanism for solid-state nucleation is used to explain the nucleation of NC-based propellants in the sol id state.Since some specific foaming behaviors of NC-based propellants can not be explained by the failure mechanism,a solid-state nucleation mechanism which revises the triaxial tensile failure mechanism is proposed and discussed.
基金supported by Chongqing Research Program of Basic Research and Frontier Technology (No.cstc2013jcyj A70004)Scientific and Technological Research Program of Chongqing Municipal Education Commission (No.KJ1501314 )Chongqing University of Science & Technology (No.CK2014Z27)
文摘A method was established for qualitative and quantitative determination of the reducing substances from plastic blood bags aqueous extract.The samples were extracted with a solid-phase extraction procedure,dichloromethane qua extract solvents,and were measured with GC-MS.With this method,we determined several reducing substances from plastic blood bags aqueous extract and fixed quantify on DEHP (di (2-ethylhexyl) phthalate),one of the dominating reducing substances.The method was simple and can be used for the quality control of plastic blood bags.
文摘A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.
