The formation of intragranular ferrite at inclusions was analyzed by SEM-EDX in a vanadium microalloyed steel with an excess amount of sulfur. The precipitation of MnS at aluminum oxides may result in Mn depletion, wh...The formation of intragranular ferrite at inclusions was analyzed by SEM-EDX in a vanadium microalloyed steel with an excess amount of sulfur. The precipitation of MnS at aluminum oxides may result in Mn depletion, which, in turn, promotes the formation of intragranular ferrite. The morphology of intragranular ferrite changed with undercooling. At higher temperatures intragranular ferrite is nearly equiaxed whereas it is plate-like at lower temperatures.展开更多
The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using ...The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.展开更多
The effects of hydrogen on the mechanical response of pure iron with randomly distributed hydrogen atoms under nanoindentation were systematically investigated by molecular dynamics simulations with the aim to further...The effects of hydrogen on the mechanical response of pure iron with randomly distributed hydrogen atoms under nanoindentation were systematically investigated by molecular dynamics simulations with the aim to further understand hydrogen embrittlement mechanism in the steels.The simulations results revealed that,for the three models with[001],[110]and[111]surface normal,hydrogen reduced the critical load of the pop-in event,promoted the dislocation slipping and reduced the plastic region size and dislocation density around the indenter compared to the hydrogen free model.Meanwhile,the different mechanical responses of the three models with different surface normal were further explained in the perspective of Schmid factor.展开更多
In this study,the impact of retained austenite on corrosion initiation,propagation,and resistance of ultrafine bainitic steels in marine environments based on the one-step and two-step bainitic isothermal transformati...In this study,the impact of retained austenite on corrosion initiation,propagation,and resistance of ultrafine bainitic steels in marine environments based on the one-step and two-step bainitic isothermal transformation was investigated using a combination of theoretical calculations and experimental methods.According to the results,the microstructure of ultrafine bainitic steels was composed of parallel arranged bainite ferrite(BF)and retained austenite(RA).The fraction of the block RA was significantly reduced,whereas the amount of the film RA increased through the two-step bainitic transformation.In the initial stage of corrosion,micro-galvanic effects occurred between the multiphases due to the difference in nobility,leading to the selective dissolution of BF sheaves,which is adjacent to the block RA in the one-step bainitic steel.However,uniformly distributed film RA in the two-step bainitic steel acted as a barrier against corrosion propagation.The electrochemical measurements and neutral salt spray tests revealed a relatively lower corrosion rate for the two-step bainitic steel,indicating a higher corrosion resistance than the one-step bainitic steel.The corrosion products layer mainly consisted ofα-FeOOH,γ-FeOOH,and Fe_(3)O_(4),which were stable and favorable for the formation of a protective rust layer.展开更多
The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. ...The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.展开更多
Gastric cancer(GC)ranks fifth in global cancer diagnosis and fourth in cancer-related death.Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival,the low ...Gastric cancer(GC)ranks fifth in global cancer diagnosis and fourth in cancer-related death.Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival,the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages,which leads to unsatisfactory prognosis and high recurrence rates.With the recent advances in genome analysis,biomarkers have been identified that have clinical importance for GC diagnosis,treatment,and prognosis.Modern molecular classifications have uncovered the vital roles that signaling pathways,including EGFR/HER2,p53,PI3K,immune checkpoint pathways,and cell adhesion signaling molecules,play in GC tumorigenesis,progression,metastasis,and therapeutic responsiveness.These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients.Nevertheless,the relative significance,temporal activation,interaction with GC risk factors,and crosstalk between these signaling pathways in GC are not well understood.Here,we review the regulatory roles of signaling pathways in GC potential biomarkers,and therapeutic targets with an emphasis on recent discoveries.Current therapies,including signaling-based and immunotherapies exploited in the past decade,and the development of treatment for GC,particularly the challenges in developing precision medications,are discussed.These advances provide a direction for the integration of clinical,molecular,and genomic profiles to improve GC diagnosis and treatments.展开更多
基金This project was sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the Education Ministry of China and by the Scientific Research Fund of the Education Bureau of Hubei Province, China (No.2004Q001).
文摘The formation of intragranular ferrite at inclusions was analyzed by SEM-EDX in a vanadium microalloyed steel with an excess amount of sulfur. The precipitation of MnS at aluminum oxides may result in Mn depletion, which, in turn, promotes the formation of intragranular ferrite. The morphology of intragranular ferrite changed with undercooling. At higher temperatures intragranular ferrite is nearly equiaxed whereas it is plate-like at lower temperatures.
基金supported by the National Natural Science Foundation of China(Nos.U20A20279 and 51601137)the Hubei Province Key Laboratory of Systems Science in Metallurgical Process(No.Y202207).
文摘The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(Nos.52071238,&U20A20279)the National Key Research and Development Program of China(No.2022YFB3706701)the 111 Project(No.D18018).
文摘The effects of hydrogen on the mechanical response of pure iron with randomly distributed hydrogen atoms under nanoindentation were systematically investigated by molecular dynamics simulations with the aim to further understand hydrogen embrittlement mechanism in the steels.The simulations results revealed that,for the three models with[001],[110]and[111]surface normal,hydrogen reduced the critical load of the pop-in event,promoted the dislocation slipping and reduced the plastic region size and dislocation density around the indenter compared to the hydrogen free model.Meanwhile,the different mechanical responses of the three models with different surface normal were further explained in the perspective of Schmid factor.
基金supported by the Wuhan Knowledge Innovation Program(20220108101020316)the Hubei Province Key Laboratory of Systems Science in Metallurgical Process(Y202104)the National Nature Science Foundation of China(52071238 and U20A20279).
文摘In this study,the impact of retained austenite on corrosion initiation,propagation,and resistance of ultrafine bainitic steels in marine environments based on the one-step and two-step bainitic isothermal transformation was investigated using a combination of theoretical calculations and experimental methods.According to the results,the microstructure of ultrafine bainitic steels was composed of parallel arranged bainite ferrite(BF)and retained austenite(RA).The fraction of the block RA was significantly reduced,whereas the amount of the film RA increased through the two-step bainitic transformation.In the initial stage of corrosion,micro-galvanic effects occurred between the multiphases due to the difference in nobility,leading to the selective dissolution of BF sheaves,which is adjacent to the block RA in the one-step bainitic steel.However,uniformly distributed film RA in the two-step bainitic steel acted as a barrier against corrosion propagation.The electrochemical measurements and neutral salt spray tests revealed a relatively lower corrosion rate for the two-step bainitic steel,indicating a higher corrosion resistance than the one-step bainitic steel.The corrosion products layer mainly consisted ofα-FeOOH,γ-FeOOH,and Fe_(3)O_(4),which were stable and favorable for the formation of a protective rust layer.
基金financial support from the National Natural Science Foundation of China (Nos. 51531007 and 51771050)the National program for the Young Top-notch Professionalsthe Fundamental Research Funds for the Central Universities (N170205002)
文摘The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.
基金National Natural Science Foundation of China#U20A20379National Key Research and Development Program of China#2018YFA0902801+2 种基金100 Top Talents Program of Sun Yat-Sen University(ZSQYBRJH0001)Guangdong Basic and Applied Basic Research Foundation#2021A1515010117Guangdong Provincial Key Laboratory of Digestive Cancer Research#2021B1212040006.
文摘Gastric cancer(GC)ranks fifth in global cancer diagnosis and fourth in cancer-related death.Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival,the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages,which leads to unsatisfactory prognosis and high recurrence rates.With the recent advances in genome analysis,biomarkers have been identified that have clinical importance for GC diagnosis,treatment,and prognosis.Modern molecular classifications have uncovered the vital roles that signaling pathways,including EGFR/HER2,p53,PI3K,immune checkpoint pathways,and cell adhesion signaling molecules,play in GC tumorigenesis,progression,metastasis,and therapeutic responsiveness.These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients.Nevertheless,the relative significance,temporal activation,interaction with GC risk factors,and crosstalk between these signaling pathways in GC are not well understood.Here,we review the regulatory roles of signaling pathways in GC potential biomarkers,and therapeutic targets with an emphasis on recent discoveries.Current therapies,including signaling-based and immunotherapies exploited in the past decade,and the development of treatment for GC,particularly the challenges in developing precision medications,are discussed.These advances provide a direction for the integration of clinical,molecular,and genomic profiles to improve GC diagnosis and treatments.
