In as-cast Mg?2.1Gd?1.1Y?0.82Zn?0.11Zr(mole fraction,%)alloy,lamellar microstructures that extend from grain boundaries to the interior ofα-Mg grains are identified as clusters ofγ′using a scanning transmission ele...In as-cast Mg?2.1Gd?1.1Y?0.82Zn?0.11Zr(mole fraction,%)alloy,lamellar microstructures that extend from grain boundaries to the interior ofα-Mg grains are identified as clusters ofγ′using a scanning transmission electron microscope equipped with a high-angle annular dark-field detector.Under a total strain-controlled low-cyclic loading at573K,the mechanical response and failure mechanism of Mg?2.1Gd?1.1Y?0.82Zn?0.11Zr alloy(T6peak-aging heat treatment)were investigated.Results show that the alloy exhibits cyclic softening response at diverse total strain amplitudes and573K.The experimental observations using scanning electron microscopy show that the micro-cracks initiate preferentially at the interface between long-period stacking order structures andα-Mg matrix and extend along the basal plane ofα-Mg.The massive long-period stacking order structures distributed at grain boundaries impede the transgranular propagation of cracks.展开更多
Two years after the coronavirus disease 2019(COVID-19)outbreak,an increasing number of patients continue to suffer from long COVID(LC),persistent symptoms,and/or delayed or long-term complications beyond the initial 4...Two years after the coronavirus disease 2019(COVID-19)outbreak,an increasing number of patients continue to suffer from long COVID(LC),persistent symptoms,and/or delayed or long-term complications beyond the initial 4 weeks from the onset of symptoms.Constant fatigue is one of the most common LC symptoms,leading to severely reduced quality of life among patients.Ginseng Radix et Rhizoma—known as the King of Herbs in traditional Chinese medicine—has shown clinical anti-fatigue effects.In this review,we summarize the underlying anti-fatigue mechanisms of Ginseng Radix et Rhizoma extracts and their bioactive compounds,with a special focus on anti-viral,immune remodeling,endocrine system regulation,and metabolism,suggesting that Ginseng Radix et Rhizoma is a potentially promising treatment for LC,especially regarding targeting fatigue.展开更多
Objective: To observe the clinical efficacy of electroacupuncture plus interferential current therapy(ICT) in treating chronic fatigue syndrome(CFS), and to explore the mechanism. Methods: Sixty eligible CFS patients ...Objective: To observe the clinical efficacy of electroacupuncture plus interferential current therapy(ICT) in treating chronic fatigue syndrome(CFS), and to explore the mechanism. Methods: Sixty eligible CFS patients were randomized into a treatment group and a control group, 30 in each group. The treatment group was intervened by electroacupuncture plus ICT, while the control group was by electroacupuncture alone. The therapeutic efficacies were evaluated after 2 treatment courses and compared between the two groups. Results: The recovery rate and total effective rate were respectively 43.3% and 93.3% in the treatment group, versus 20.0% and 80.0% in the control group. There were significant differences in comparing the recovery rate and total effective rate between the two groups(P<0.05), showing that the recovery rate and total effective rate in the treatment group were higher than those in the control group. Conclusion: Electroacupuncture plus ICT can produce a remarkable efficacy in treating CFS.展开更多
In-service Very-High-Cycle-Fatigue(VHCF)regime of compressor vane and turbine rotor blades of the Al-based alloy VD-17and superalloy GS6K,respectively,was considered.Surface crack origination occurred at the lifetime ...In-service Very-High-Cycle-Fatigue(VHCF)regime of compressor vane and turbine rotor blades of the Al-based alloy VD-17and superalloy GS6K,respectively,was considered.Surface crack origination occurred at the lifetime more than 1500 hours for vanes and after 550 hours for turbine blades.Performed fractographic investigations have shown that subsurface crack origination in vanes took place inspite of corrosion pittings on the blade surface.This material behavior reflected lifetime limit that was reached by the criterion VHCF.In superalloy GS6K subsurface fatigue cracking took place with the appearance of flat facet.This phenomenon was discussed and compared with specimens cracking of the same superalloy but prepared by the powder technology.In turbine blades VHCF regime appeared because of resonance of blades under the influenced gas stream.Both cases of compressor-vanes and turbine blades in-service cracking were discussed with crack growth period and stress equivalent estimations.Recommendations to continue aircrafts airworthiness were made for in-service blades.展开更多
基金Project(2015TP1035)supported by the Science and Technology Planning Project of Hunan Province,ChinaProject(531107040183)supported by the Fundamental Research Funds for the Central Universities,China
文摘In as-cast Mg?2.1Gd?1.1Y?0.82Zn?0.11Zr(mole fraction,%)alloy,lamellar microstructures that extend from grain boundaries to the interior ofα-Mg grains are identified as clusters ofγ′using a scanning transmission electron microscope equipped with a high-angle annular dark-field detector.Under a total strain-controlled low-cyclic loading at573K,the mechanical response and failure mechanism of Mg?2.1Gd?1.1Y?0.82Zn?0.11Zr alloy(T6peak-aging heat treatment)were investigated.Results show that the alloy exhibits cyclic softening response at diverse total strain amplitudes and573K.The experimental observations using scanning electron microscopy show that the micro-cracks initiate preferentially at the interface between long-period stacking order structures andα-Mg matrix and extend along the basal plane ofα-Mg.The massive long-period stacking order structures distributed at grain boundaries impede the transgranular propagation of cracks.
基金funded by the Science&Technology Development Fund of the Tianjin Education Commission for Higher Education(2018KJ010)。
文摘Two years after the coronavirus disease 2019(COVID-19)outbreak,an increasing number of patients continue to suffer from long COVID(LC),persistent symptoms,and/or delayed or long-term complications beyond the initial 4 weeks from the onset of symptoms.Constant fatigue is one of the most common LC symptoms,leading to severely reduced quality of life among patients.Ginseng Radix et Rhizoma—known as the King of Herbs in traditional Chinese medicine—has shown clinical anti-fatigue effects.In this review,we summarize the underlying anti-fatigue mechanisms of Ginseng Radix et Rhizoma extracts and their bioactive compounds,with a special focus on anti-viral,immune remodeling,endocrine system regulation,and metabolism,suggesting that Ginseng Radix et Rhizoma is a potentially promising treatment for LC,especially regarding targeting fatigue.
基金supported by Taihe Hospital, Hubei University of Medicine
文摘Objective: To observe the clinical efficacy of electroacupuncture plus interferential current therapy(ICT) in treating chronic fatigue syndrome(CFS), and to explore the mechanism. Methods: Sixty eligible CFS patients were randomized into a treatment group and a control group, 30 in each group. The treatment group was intervened by electroacupuncture plus ICT, while the control group was by electroacupuncture alone. The therapeutic efficacies were evaluated after 2 treatment courses and compared between the two groups. Results: The recovery rate and total effective rate were respectively 43.3% and 93.3% in the treatment group, versus 20.0% and 80.0% in the control group. There were significant differences in comparing the recovery rate and total effective rate between the two groups(P<0.05), showing that the recovery rate and total effective rate in the treatment group were higher than those in the control group. Conclusion: Electroacupuncture plus ICT can produce a remarkable efficacy in treating CFS.
文摘In-service Very-High-Cycle-Fatigue(VHCF)regime of compressor vane and turbine rotor blades of the Al-based alloy VD-17and superalloy GS6K,respectively,was considered.Surface crack origination occurred at the lifetime more than 1500 hours for vanes and after 550 hours for turbine blades.Performed fractographic investigations have shown that subsurface crack origination in vanes took place inspite of corrosion pittings on the blade surface.This material behavior reflected lifetime limit that was reached by the criterion VHCF.In superalloy GS6K subsurface fatigue cracking took place with the appearance of flat facet.This phenomenon was discussed and compared with specimens cracking of the same superalloy but prepared by the powder technology.In turbine blades VHCF regime appeared because of resonance of blades under the influenced gas stream.Both cases of compressor-vanes and turbine blades in-service cracking were discussed with crack growth period and stress equivalent estimations.Recommendations to continue aircrafts airworthiness were made for in-service blades.
