C/C composites with banded structure pyrocarbon were fabricated by fast chemical vapor infiltration（CVI）,with C3H6 as carbon source,N2 as carrier gas,and three-dimensional（3D） 12K PAN-based carbon fabric with high...C/C composites with banded structure pyrocarbon were fabricated by fast chemical vapor infiltration（CVI）,with C3H6 as carbon source,N2 as carrier gas,and three-dimensional（3D） 12K PAN-based carbon fabric with high density of 0.94 g/cm3 as preform.Experimental results indicated that the fracture characteristics of C/C composites were closely related to the frequency of high-temperature treatment（HTT） at the break of CVI process.According to the load？displacement curves,C/C composites showed a pseudoplastic fracture after twice of HTT.After three times of HTT,load？displacement curves tended to be stable with a decreasing bending strength at 177.5 MPa.Delamination failure and intrastratal fiber fracture were observed at the cross-section of C/C composites by scanning electronic microscope.Because the content of pyrocarbon and fibers has a different distribution in layers,the C/C composites show different fracture characteristics at various regions,which leads to good toughness and bending strength.展开更多
Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chem...Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.展开更多
Using natural gas as carbon source, 2D needle felt as preform, 2D-C/C composites were prepared by thermal gradient chemical vapor infiltration. Their microstructures were observed under polarized light microscope （PL...Using natural gas as carbon source, 2D needle felt as preform, 2D-C/C composites were prepared by thermal gradient chemical vapor infiltration. Their microstructures were observed under polarized light microscope （PLM） and scanning electron microscope （SEM）, and the flexural behaviors before and after heat-treatment were studied with a universal mechanical testing machine. The fracture mechanism of the composites was discussed in detail. The results show that, carbon matrix exhibits pure smooth laminar （SL） characteristic including numerous wrinkled layered structures and some inter-laminar micro-cracks. With the decreasing density, the strength of the composites decreases and the toughness increases slightly; after 2500 °C heat-treatment, the inter-laminar micro-cracks in matrix increase, the strength decreases, and the toughness obviously increases. The fracture mode of the composites changes from brittle to pseudo-plastic characteristic due to more crack deflections in SL matrix.展开更多
KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the ele...KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the electron/ion transfer by tuning electronic structure,thus providing favorable electrochemical performance.Herein,through the regulation of surface defect engineering in reduced graphene oxide(rGO),the Fe–C bonds were formed between KFSF and rGO.The Fe–C bonds formed work in regulating the Fe-3d orbital as well as promoting the migration ability of K ions and increasing the electronic conductivity of KFSF.Thus,the KFSF@rGO delivers a high capacity of 119.6 mAh g^(-1).When matched with a graphite@pitch-derived S-doped carbon anode,the full cell delivers an energy density of 250.5 Wh kg^(-1) and a capacity retention of 81.5%after 400 cycles.This work offers a simple and valid method to develop high-performance cathodes by tuning defect sites.展开更多
A unidirectional carbon/carbon composite (1D-C/C) of low bulk density with textures of poruns granular and isotropic carbons sharply manifests brittle fracture and does not display high pseudoplasticity as expected. ...A unidirectional carbon/carbon composite (1D-C/C) of low bulk density with textures of poruns granular and isotropic carbons sharply manifests brittle fracture and does not display high pseudoplasticity as expected. The results of transmisson electron microscopy (TEM) studies show that the strong interface of fiber-matrix should determine its fracture mode.展开更多
Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the U...Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the United States of America.In this study,the performance of the 3-and 9-story Los Angeles pre-Northridge SAC buildings are analyzed considering ductile and brittle beam-column connection failures,and their uncertainty.This paper contributes to understanding the influence of uncertainty associated with connections brittle fracture on building interstory deformation capacity and its impact on bias and variability of fragility functions and loss assessment.The results show that considering brittle connections leads to significantly l arger d rift demands a nd t o h igher r epair costs,particularly under intense ground shaking.New fragility curve parameters are derived that account for the effect of the uncertainty of the strength and deformation capacity of brittle connections.展开更多
基金Project (50802115) supported by the National Natural Science Foundation of ChinaProject (2011CB605801) supported by the National Basic Research Program of China
文摘C/C composites with banded structure pyrocarbon were fabricated by fast chemical vapor infiltration（CVI）,with C3H6 as carbon source,N2 as carrier gas,and three-dimensional（3D） 12K PAN-based carbon fabric with high density of 0.94 g/cm3 as preform.Experimental results indicated that the fracture characteristics of C/C composites were closely related to the frequency of high-temperature treatment（HTT） at the break of CVI process.According to the load？displacement curves,C/C composites showed a pseudoplastic fracture after twice of HTT.After three times of HTT,load？displacement curves tended to be stable with a decreasing bending strength at 177.5 MPa.Delamination failure and intrastratal fiber fracture were observed at the cross-section of C/C composites by scanning electronic microscope.Because the content of pyrocarbon and fibers has a different distribution in layers,the C/C composites show different fracture characteristics at various regions,which leads to good toughness and bending strength.
基金National Yang Ming Chiao Tung University Far Eastern Memorial Hospital Joint Research Programs(NYCU-FEMH 109DN03,110DN06,111DN04,112DN05).
文摘Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.
基金Projects(51221001,51202193)supported by the National Natural Science Foundation of ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘Using natural gas as carbon source, 2D needle felt as preform, 2D-C/C composites were prepared by thermal gradient chemical vapor infiltration. Their microstructures were observed under polarized light microscope （PLM） and scanning electron microscope （SEM）, and the flexural behaviors before and after heat-treatment were studied with a universal mechanical testing machine. The fracture mechanism of the composites was discussed in detail. The results show that, carbon matrix exhibits pure smooth laminar （SL） characteristic including numerous wrinkled layered structures and some inter-laminar micro-cracks. With the decreasing density, the strength of the composites decreases and the toughness increases slightly; after 2500 °C heat-treatment, the inter-laminar micro-cracks in matrix increase, the strength decreases, and the toughness obviously increases. The fracture mode of the composites changes from brittle to pseudo-plastic characteristic due to more crack deflections in SL matrix.
基金support from the National Key R&D Program of China(Grant No.2023YFE0202000)National Natural Science Foundation of China(Grant No.52102213)Science Technology Program of Jilin Province(Grant No.20230101128JC).
文摘KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the electron/ion transfer by tuning electronic structure,thus providing favorable electrochemical performance.Herein,through the regulation of surface defect engineering in reduced graphene oxide(rGO),the Fe–C bonds were formed between KFSF and rGO.The Fe–C bonds formed work in regulating the Fe-3d orbital as well as promoting the migration ability of K ions and increasing the electronic conductivity of KFSF.Thus,the KFSF@rGO delivers a high capacity of 119.6 mAh g^(-1).When matched with a graphite@pitch-derived S-doped carbon anode,the full cell delivers an energy density of 250.5 Wh kg^(-1) and a capacity retention of 81.5%after 400 cycles.This work offers a simple and valid method to develop high-performance cathodes by tuning defect sites.
文摘A unidirectional carbon/carbon composite (1D-C/C) of low bulk density with textures of poruns granular and isotropic carbons sharply manifests brittle fracture and does not display high pseudoplasticity as expected. The results of transmisson electron microscopy (TEM) studies show that the strong interface of fiber-matrix should determine its fracture mode.
文摘Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the United States of America.In this study,the performance of the 3-and 9-story Los Angeles pre-Northridge SAC buildings are analyzed considering ductile and brittle beam-column connection failures,and their uncertainty.This paper contributes to understanding the influence of uncertainty associated with connections brittle fracture on building interstory deformation capacity and its impact on bias and variability of fragility functions and loss assessment.The results show that considering brittle connections leads to significantly l arger d rift demands a nd t o h igher r epair costs,particularly under intense ground shaking.New fragility curve parameters are derived that account for the effect of the uncertainty of the strength and deformation capacity of brittle connections.
