The reliability based optimization （RBO） issue of composite laminates trader fundamental frequency constraint is studied. Considering the tmcertainties of material properties, the frequency constraint reliability of...The reliability based optimization （RBO） issue of composite laminates trader fundamental frequency constraint is studied. Considering the tmcertainties of material properties, the frequency constraint reliability of the structure is evaluated by the combination of response surface method （RSM） and finite element method. An optimization algorithm is developed based on the mechanism of laminate frequency characteristics, to optimize the laminate in terms of the ply amount and orientation angles. Numerical examples of composite laminates and cylindrical shell illustrate the advantages of the present optimization algorithm on the efficiency and applicability respects. The optimal solutions of RBO are obviously different from the deterministic optimization results, and the necessity of considering material property uncertainties in the composite structural frequency constraint optimization is revealed.展开更多
A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffr...A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.展开更多
The production of reactive oxygen species(ROS)by NADPH oxidase,which is also referred to as respiratory burst oxidase homolog(RBOH),affects several processes in plants.However,the role of RBOHs in cell wall lignificat...The production of reactive oxygen species(ROS)by NADPH oxidase,which is also referred to as respiratory burst oxidase homolog(RBOH),affects several processes in plants.However,the role of RBOHs in cell wall lignification is not well understood.In this study,we show that PuRBOHF,an RBOH isoform,plays an important role in secondary wall formation in pear stone cells.ROS were closely associated with lignin deposition and stone cell formation according to microscopy data.In addition,according to the results of an in situ hybridization analysis,the stage-specific expression of PuRBOHF was higher in stone cells than in cells of other flesh tissues.Inhibitors of RBOH activity suppressed ROS accumulation and stone cell lignification in pear fruit.Moreover,transient overexpression of PuRBOHF caused significant changes in the amount of ROS and lignin that accumulated in pear fruit and flesh calli.We further showed that PuMYB169 regulates PuRBOHF expression,while PuRBOHF-derived ROS induces the transcription of PuPOD2 and PuLAC2.The findings of this study indicate that PuRBOHF-mediated ROS production,which is regulated by a lignin-related transcriptional network,is essential for monolignol polymerization and stone cell formation in pear fruit.展开更多
Mixed culture fermentation(MCF)is challenged by the unqualified activity of enriched bacteria and unwanted methane dissolution under low temperatures.In this work,caproate production from xylose was investigated by MC...Mixed culture fermentation(MCF)is challenged by the unqualified activity of enriched bacteria and unwanted methane dissolution under low temperatures.In this work,caproate production from xylose was investigated by MCF at a low temperature(20°C).The results showed that a 9 d long hydraulic retention time(HRT)in a continuously stirred tank reactor was necessary for caproate production(~0.3 g/L,equal to 0.6 g COD/L)from xylose(10 g/L).The caproate concentration in the batch mode was further increased to 1.6 g/L.However,changing the substrate to ethanol did not promote caproate production,resulting in~1.0 g/L after 45 d of operation.Four genera,Bifidobacterium,Caproiciproducens,Actinomyces,and Clostridium_sensu_stricto_12,were identified as the enriched caproate-producing bacteria.The enzymes in the fatty acid biosynthesis(FAB)pathway for caproate production were identified via metagenomic analysis.The enzymes for the conversion of(C_(n+2))-2,3-Dehydroxyacyl-CoA to(C_(n+2))-Acyl-CoA(i.e.,EC 1.3.1.8 and EC 1.3.1.38)in the reverseβ-oxidation(RBO)pathway were not identified.These results could extend the understanding of low-temperature caproate production.展开更多
基金National Natural Science Foundation of China (51412060104HK0123)
文摘The reliability based optimization （RBO） issue of composite laminates trader fundamental frequency constraint is studied. Considering the tmcertainties of material properties, the frequency constraint reliability of the structure is evaluated by the combination of response surface method （RSM） and finite element method. An optimization algorithm is developed based on the mechanism of laminate frequency characteristics, to optimize the laminate in terms of the ply amount and orientation angles. Numerical examples of composite laminates and cylindrical shell illustrate the advantages of the present optimization algorithm on the efficiency and applicability respects. The optimal solutions of RBO are obviously different from the deterministic optimization results, and the necessity of considering material property uncertainties in the composite structural frequency constraint optimization is revealed.
基金Project supported by the National Natural Science Foundation of China (No. 50674062)the Key Projects in the National Science & Technology Pillar Program (No. 2006BAC21B03)the Beijing Science and Technology Plan Projects of China (No. D07040300690000)
文摘A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.
基金This work was supported by the National Natural Science Foundation of China(31701865)the Liaoning Provincial Natural Science Foundation of China(2019-MS-276)the Research Foundation of the Education Bureau of Liaoning Province and the China Agriculture Research System of MOF and MARAE.
文摘The production of reactive oxygen species(ROS)by NADPH oxidase,which is also referred to as respiratory burst oxidase homolog(RBOH),affects several processes in plants.However,the role of RBOHs in cell wall lignification is not well understood.In this study,we show that PuRBOHF,an RBOH isoform,plays an important role in secondary wall formation in pear stone cells.ROS were closely associated with lignin deposition and stone cell formation according to microscopy data.In addition,according to the results of an in situ hybridization analysis,the stage-specific expression of PuRBOHF was higher in stone cells than in cells of other flesh tissues.Inhibitors of RBOH activity suppressed ROS accumulation and stone cell lignification in pear fruit.Moreover,transient overexpression of PuRBOHF caused significant changes in the amount of ROS and lignin that accumulated in pear fruit and flesh calli.We further showed that PuMYB169 regulates PuRBOHF expression,while PuRBOHF-derived ROS induces the transcription of PuPOD2 and PuLAC2.The findings of this study indicate that PuRBOHF-mediated ROS production,which is regulated by a lignin-related transcriptional network,is essential for monolignol polymerization and stone cell formation in pear fruit.
基金the National Natural Science Foundation of China(Nos.51808120 and 52170127)China Postdoctoral Science Foundation(No.2019M652235)the Program for Innovative Research Team in Science and Technology in Fujian Province University(China)(IRTSTFJ).
文摘Mixed culture fermentation(MCF)is challenged by the unqualified activity of enriched bacteria and unwanted methane dissolution under low temperatures.In this work,caproate production from xylose was investigated by MCF at a low temperature(20°C).The results showed that a 9 d long hydraulic retention time(HRT)in a continuously stirred tank reactor was necessary for caproate production(~0.3 g/L,equal to 0.6 g COD/L)from xylose(10 g/L).The caproate concentration in the batch mode was further increased to 1.6 g/L.However,changing the substrate to ethanol did not promote caproate production,resulting in~1.0 g/L after 45 d of operation.Four genera,Bifidobacterium,Caproiciproducens,Actinomyces,and Clostridium_sensu_stricto_12,were identified as the enriched caproate-producing bacteria.The enzymes in the fatty acid biosynthesis(FAB)pathway for caproate production were identified via metagenomic analysis.The enzymes for the conversion of(C_(n+2))-2,3-Dehydroxyacyl-CoA to(C_(n+2))-Acyl-CoA(i.e.,EC 1.3.1.8 and EC 1.3.1.38)in the reverseβ-oxidation(RBO)pathway were not identified.These results could extend the understanding of low-temperature caproate production.
