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碳纳米管选择性分布增韧聚乳酸/聚己二酸对苯二甲酸丁二醇酯共混材料
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作者 李桂丽 冯巧 +6 位作者 陈树芳 尹田欣 何彝昕 谢丹 毛辰静 邵春光 高蓬 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2024年第7期63-69,共7页
采用碳纳米管(CNTs)来调控聚乳酸(PLA)/聚己二酸对苯二甲酸丁二醇酯(PBAT)共混材料的微结构和宏观性能,探究了CNTs添加量对PLA/PBAT共混物结晶行为、相形貌及热力学性能的影响规律,基于润湿理论量化分析了CNTs选择性分布的原因,探讨了C... 采用碳纳米管(CNTs)来调控聚乳酸(PLA)/聚己二酸对苯二甲酸丁二醇酯(PBAT)共混材料的微结构和宏观性能,探究了CNTs添加量对PLA/PBAT共混物结晶行为、相形貌及热力学性能的影响规律,基于润湿理论量化分析了CNTs选择性分布的原因,探讨了CNTs增韧PLA/PBAT共混材料的内在机制。结果表明,CNTs选择性分布在PBAT中,显著增大了PBAT相的粒径,使共混材料相形貌粗化,暗示CNTs不具备增容作用;提高CNTs的添加量,共混材料拉伸强度略有降低,断裂伸长率大幅提升;CNTs的质量分数为1%时,PLA/PBAT/CNTs试样的断裂伸长率达到最大,与未添加CNTs的PLA/PBAT试样相比提高了258.6%。 展开更多
关键词 聚乳酸 聚己二酸对苯二甲酸丁二醇酯 碳纳米管 选择性分布 增韧
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Divergent responses of growth rate and antioxidative system of ten Bacillus strains to acid stresses 被引量:1
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作者 Xiaoran Shan Jiayi chen +3 位作者 Jiaen Zhang Ziqiang Liu shufang chen Hui Wei 《Soil Ecology Letters》 CSCD 2024年第1期107-118,共12页
Response of growth rate and antioxidative system of ten Bacillus strains to acid stresses was assayed.Strong acid treatment significantly decreased the growth rate of the strains.Acid stresses increased the GPX activi... Response of growth rate and antioxidative system of ten Bacillus strains to acid stresses was assayed.Strong acid treatment significantly decreased the growth rate of the strains.Acid stresses increased the GPX activity and GSSG content of the tested strains.Divergent changes occurred in ROS and antioxidative system(SOD,CAT,GR,MDA and GSH).Environmental changes including soil acidification exert obvi-ous stresses on soil ecosystems and influence soil microor-ganisms.In this study,ten microbial strains were incubated under different acid treatments to investigate responses of microbial growth and antioxidative system to acid stress.All the strains belong to Bacillus genus,but exhibit distinct ecological functions.We observed that these microbial strains had obviously different pH tolerance threshold,in spite of the close phylogenetic classification among strains.Acid stresses exerted significant effects on microbial antiox-idative system,including superoxide dismutase(SOD),cata-lase(CAT)and glutathione transferring enzymes(GPX and GR)and reactants(GSH and GSSH),but the effects were strain specific.Furthermore,we found acid stress effects on total variances of the investigated microbial antioxidative system along the first two principal components(PCs).Activities of CAT and SOD contributed substantially to PC1 that reflected obvious acid effects on NC7 and ZC4,and closely related to intracellular malondialdehyde content.The GSSG activities and GSH/GSSG contributed greatly to PC2 that unveiled acid stress effects on most of the microbial strains.Our results highlight substantially heterogeneous responses of microbial strains to acid stress and support that phylogenetic closeness does not imply functional similarity of soil microorganisms under environmental changes. 展开更多
关键词 soil acidification microbial strain acid tolerance capacity microbial growth oxidative stress antioxidative system
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Migration characteristics and profile control capabilities of preformed particle gel in porous media 被引量:1
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作者 Nanjun Lai shufang chen +2 位作者 Lei Tang Yuaojie Huang Hongwei Xu 《Petroleum》 EI CSCD 2022年第4期483-498,共16页
Inspired by the viscoelastic displacement theory,a product called preformed particle gel(PPG)is developed as conformance control agent to enhance oil recovery and control excess water production.The migration law of P... Inspired by the viscoelastic displacement theory,a product called preformed particle gel(PPG)is developed as conformance control agent to enhance oil recovery and control excess water production.The migration law of PPG suspension in porous media is related to its deep profile control and displacement capability.Laboratory experiments indicate that PPG suspension has good viscosity increasing,and the apparent viscosity decreases with the increase of shear rate.PPG suspension is mainly elastic,and its network structure makes it have certain shear stability.PPG particles realize migration in porous media in the way of“accumulation and blockage/pressure increase/deformation and migration”.When the ratio of the PPG particle size to the pore throat diameter d ranges from 35.52 to 53.38,the particles can match through the porous medium.When the permeability difference of the parallel model is 5,PPG suspension has the highest profile improvement rate,69.10%.PPG suspension can adjust the planar heterogeneity,and increase the oil recovery rate by 20.75%.The PPG suspension can effectively start“cluster"、“film”and“blind end residual oil”,and has a high oil washing efficiency.The core NMR T2 spectrum shows that PPG suspension mainly reduces oil saturation in mesopores and macropores.After PPG flooding,the EOR capacity of small pores is the highest,39.11%. 展开更多
关键词 Preformed particle gel(PPG) Migration law Profile control Flow characteristics Microscopic oil displacement
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Threshold analysis for epidemic models with high-risk immunization on networks 被引量:1
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作者 Qingchu Wu shufang chen 《International Journal of Biomathematics》 2015年第3期73-82,共10页
In this paper, an SIRS epidemic model with high-risk immunization was investigated, where a susceptible neighbor of an infected node is immunized with rate h. Through analyzing the discrete-time model, we found that t... In this paper, an SIRS epidemic model with high-risk immunization was investigated, where a susceptible neighbor of an infected node is immunized with rate h. Through analyzing the discrete-time model, we found that the epidemic threshold above which an epidemic can prevail and persist in a population is inversely proportional to 1 - h value. We also studied the continuous-time epidemic model and obtained a different result: the epidemic threshold does not depend on the immunization parameter h. Our results suggest that the difference between the discrete-time epidemic model and the continuous-time epidemic model exists in the high-risk immunization. 展开更多
关键词 Complex network epidemic dynamics MODEL dynamic immunization.
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