This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),YGdTbDyHo.Results indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with t...This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),YGdTbDyHo.Results indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with the alloy elements distributed homogeneously.Upon hydrogen absorption,the phase structure of the HEA changed from a solid solution with an hexagonal-close-packed(HCP)structure to a high-entropy hydride with an faced-centered-cubic(FCC)structure without any secondary phase precipitated.The alloy demonstrated a maximum hydrogen storage capacity of 2.33 H/M(hydrogen atom/metal atom)at 723 K,with an enthalpy change(ΔH)of-141.09 kJ·mol^(-1)and an entropy change(ΔS)of-119.14 J·mol^(-1)·K^(-1).The kinetic mechanism of hydrogen absorption was hydride nucleation and growth,with an apparent activation energy(E_(a))of 20.90 kJ·mol^(-1).Without any activation,the YGdTbDyHo alloy could absorb hydrogen quickly(180 s at 923 K)with nearly no incubation period observed.The reason for the obtained value of 2.33 H/M was that the hydrogen atoms occupied both tetrahedral and octahedral interstices.These results demonstrate the potential application of HEAs as a high-capacity hydrogen storage material with a large H/M ratio,which can be used in the deuterium storage field.展开更多
Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed composit...Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied locations.Transmission electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys.In this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs.By using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was clarified.Moreover,the perspective related to application of TEM techniques in HEAs are also discussed.展开更多
The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annula...The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent icing.This study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber.Additionally,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the system.The research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI chamber.However,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy efficiency.The nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI chamber.Increasingθfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.展开更多
This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict ...This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict the occurrence of TrRD.The in vitro experiment was performed on forty-eight porcine eyes using a pendulum device.We examined dynamic mechanical responses at four energy levels.A FE model,based on experimental results and published data,was used to simulate TrRD.Fifty-one additional eyes underwent immediate pathological examination following blunt impact.A dynamic variation of velocities was observed post-impact,displaying an approximate cosine oscillation-attenuation profile.Energy absorption increased as the initial energy and differed significantly at four energy levels(p<0.001).FE simulation showed a peak strain of 0.462 in the anterior vitreous body and a peak stress of 1.408 MPa at the cornea at the high-energy level.During the energy transfer,the stress was initially observed in retinal region along the impact direction at the separation.TrRD were observed in injured eyes,where a few detachments were detected in control eyes.Correlations were performed between the proportion of pathological outcomes and FE results.In conclusion,this study suggests that stress contributes to the development of retinal detachment,providing an indicator to distinguish the occurrence of TrRD.展开更多
1.Introduction Damping alloys are considered to be the most direct and effective approach to reducing unwanted vibration and noise in industrial applications.In particular,it is urgent to develop damping alloys that h...1.Introduction Damping alloys are considered to be the most direct and effective approach to reducing unwanted vibration and noise in industrial applications.In particular,it is urgent to develop damping alloys that have highdamping capacity(tanδ)as well as high strength,and a large operating temperature range to meet the demands of extreme working conditions,such as outer space.However,the application temperature of existing damping alloys is limited,which is one of the biggest challenges for developing highperformance damping alloys.For Fe-Mn binary alloys.展开更多
目的:探讨局部晚期鼻咽癌患者营养状况及其与预后相关性。方法:分析2015年8月至2017年3月湖北省肿瘤医院收治的局部晚期鼻咽癌住院患者53例,联合运用患者主观整体营养评估量表(patient-generated subjective global assessment,PGSGA)...目的:探讨局部晚期鼻咽癌患者营养状况及其与预后相关性。方法:分析2015年8月至2017年3月湖北省肿瘤医院收治的局部晚期鼻咽癌住院患者53例,联合运用患者主观整体营养评估量表(patient-generated subjective global assessment,PGSGA)、体格测量、血液学指标和放化疗不良反应,全面评估患者营养状况;采用Kaplan-Meier法及Cox风险比例回归模型对患者生存及影响因素进行分析。结果:53例患者中,94.3%(50/53)的患者出现体质量下降,下降均值为(6.89±0.54)kg,50.9%(27/53)的患者体质量下降≥10%;PG-SGA评估的患者重度营养不良发生率为84.9%(45/53);淋巴细胞计数、红细胞、血红蛋白、白蛋白与PG-SGA评分高度负相关(P<0.05),口腔黏膜炎、吞咽困难或疼痛、厌食、体质量下降百分比与PG-SGA评分高度正相关(P<0.05);单因素及多因素分析显示,TNM分期晚、治疗期间体质量下降≥10%与局部晚期鼻咽癌患者预后不良相关,而白细胞计数增加(在正常值范围内)与局部晚期鼻咽癌患者预后良好相关,差异均具有统计学意义(P=0.036,P=0.016,P=0.024)。结论:局部晚期鼻咽癌患者营养不良发生率高;PG-SGA评分联合体格测量、血液学指标和放化疗不良反应,能够更全面地评估患者营养状况;TNM分期晚、治疗期间体质量下降≥10%是局部晚期鼻咽癌患者预后的不良因素,而白细胞计数增加(在正常值范围内)是患者预后的有利因素。展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21171018 and 51271021)the State Key Laboratory for Advanced Metals and Materials。
文摘This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),YGdTbDyHo.Results indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with the alloy elements distributed homogeneously.Upon hydrogen absorption,the phase structure of the HEA changed from a solid solution with an hexagonal-close-packed(HCP)structure to a high-entropy hydride with an faced-centered-cubic(FCC)structure without any secondary phase precipitated.The alloy demonstrated a maximum hydrogen storage capacity of 2.33 H/M(hydrogen atom/metal atom)at 723 K,with an enthalpy change(ΔH)of-141.09 kJ·mol^(-1)and an entropy change(ΔS)of-119.14 J·mol^(-1)·K^(-1).The kinetic mechanism of hydrogen absorption was hydride nucleation and growth,with an apparent activation energy(E_(a))of 20.90 kJ·mol^(-1).Without any activation,the YGdTbDyHo alloy could absorb hydrogen quickly(180 s at 923 K)with nearly no incubation period observed.The reason for the obtained value of 2.33 H/M was that the hydrogen atoms occupied both tetrahedral and octahedral interstices.These results demonstrate the potential application of HEAs as a high-capacity hydrogen storage material with a large H/M ratio,which can be used in the deuterium storage field.
基金financially supported by the National Natural Science Foundation of China(Nos.51971017,52271003,52071024,52001184,and 52101188)the National Science Fund for distinguished Young Scholars,China(No.52225103)+3 种基金the Funds for Creative Research Groups of China(No.51921001)the National Key Research and Development Program of China(No.2022YFB4602101)the Projects of International Cooperation and Exchanges NSFC(No.52061135207)the Fundamental Research Funds for the Central Universities,China(No.FRF-TP-22-130A1)。
文摘Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied locations.Transmission electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys.In this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs.By using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was clarified.Moreover,the perspective related to application of TEM techniques in HEAs are also discussed.
基金Shenyang Key Laboratory of Aircraft Icing and Ice Protection,Grant Number XFX20220303Education Department of Hunan Province,China,Grant Number 23A0504National Natural Science Foundation of China,Grant Number 52275108.
文摘The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent icing.This study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber.Additionally,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the system.The research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI chamber.However,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy efficiency.The nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI chamber.Increasingθfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.
基金supported by the National Nature Science Foundation of China(Grant Nos.11972066,U20A20390,and 11827803)the support of Open Fund of State Key Laboratory of Virtual Reality Technology and Systems。
文摘This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict the occurrence of TrRD.The in vitro experiment was performed on forty-eight porcine eyes using a pendulum device.We examined dynamic mechanical responses at four energy levels.A FE model,based on experimental results and published data,was used to simulate TrRD.Fifty-one additional eyes underwent immediate pathological examination following blunt impact.A dynamic variation of velocities was observed post-impact,displaying an approximate cosine oscillation-attenuation profile.Energy absorption increased as the initial energy and differed significantly at four energy levels(p<0.001).FE simulation showed a peak strain of 0.462 in the anterior vitreous body and a peak stress of 1.408 MPa at the cornea at the high-energy level.During the energy transfer,the stress was initially observed in retinal region along the impact direction at the separation.TrRD were observed in injured eyes,where a few detachments were detected in control eyes.Correlations were performed between the proportion of pathological outcomes and FE results.In conclusion,this study suggests that stress contributes to the development of retinal detachment,providing an indicator to distinguish the occurrence of TrRD.
基金supported by the National Natural Science Foundation of China(Nos.52071024,52225103,51971017,52271003,and 52101188)the Funds for Creative Research Groups of NSFC(No.51921001)+6 种基金Projects of International Cooperation and Exchanges of NSFC(Nos.51961160729 and 52061135207)National Key Research and Development Program of China(Nos.2022YFB3705201 and 2022YFB4602101)111 Project(No.BP0719004)Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)the Fundamental Research Funds for the Central Universities of China:FRF-TP-22-005C2,FRF-TP-22-001C2Project funded by China Postdoctoral Science Foundation(2020M680009)by Key Laboratory of Construction Hydraulic Robots of Anhui Higher Education Institutes,Tongling University(Grant No.TLXYCHR-O-21YB02).
文摘1.Introduction Damping alloys are considered to be the most direct and effective approach to reducing unwanted vibration and noise in industrial applications.In particular,it is urgent to develop damping alloys that have highdamping capacity(tanδ)as well as high strength,and a large operating temperature range to meet the demands of extreme working conditions,such as outer space.However,the application temperature of existing damping alloys is limited,which is one of the biggest challenges for developing highperformance damping alloys.For Fe-Mn binary alloys.
文摘目的:探讨局部晚期鼻咽癌患者营养状况及其与预后相关性。方法:分析2015年8月至2017年3月湖北省肿瘤医院收治的局部晚期鼻咽癌住院患者53例,联合运用患者主观整体营养评估量表(patient-generated subjective global assessment,PGSGA)、体格测量、血液学指标和放化疗不良反应,全面评估患者营养状况;采用Kaplan-Meier法及Cox风险比例回归模型对患者生存及影响因素进行分析。结果:53例患者中,94.3%(50/53)的患者出现体质量下降,下降均值为(6.89±0.54)kg,50.9%(27/53)的患者体质量下降≥10%;PG-SGA评估的患者重度营养不良发生率为84.9%(45/53);淋巴细胞计数、红细胞、血红蛋白、白蛋白与PG-SGA评分高度负相关(P<0.05),口腔黏膜炎、吞咽困难或疼痛、厌食、体质量下降百分比与PG-SGA评分高度正相关(P<0.05);单因素及多因素分析显示,TNM分期晚、治疗期间体质量下降≥10%与局部晚期鼻咽癌患者预后不良相关,而白细胞计数增加(在正常值范围内)与局部晚期鼻咽癌患者预后良好相关,差异均具有统计学意义(P=0.036,P=0.016,P=0.024)。结论:局部晚期鼻咽癌患者营养不良发生率高;PG-SGA评分联合体格测量、血液学指标和放化疗不良反应,能够更全面地评估患者营养状况;TNM分期晚、治疗期间体质量下降≥10%是局部晚期鼻咽癌患者预后的不良因素,而白细胞计数增加(在正常值范围内)是患者预后的有利因素。
