To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the...To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.展开更多
This study carried out comprehensive analysis on sedimentology, magnetic susceptibility （7of） and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change info...This study carried out comprehensive analysis on sedimentology, magnetic susceptibility （7of） and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change information during the 129.14-122.98 Ma interval. Based on the results of the Xlf and of the redness （a＊）, the section can be divided into two segments： （1） 129.14-126.3 Ma, with the lowest Xlf values and strongly variable relatively high values of redness and （2） 126.3-122.98 Ma, with high Elf values and relatively low redness. Analysis of the lithology and facies as well as the magnetic minerals and their contents points to a detrital origin of the magnetic minerals and this allow us to interpret the relationship between magnetic susceptibility variations and climate changes. Our study shows that the climate was significantly dry and hot during the whole studied interval although the interval between 126.3 Ma and 122.98 was a little bit cooler with increased humidity.展开更多
目的探讨揿针干预对乳腺癌术后患者下丘脑-垂体-肾上腺轴(Hypothalamic-pituitaryadrenal axis,HPA)功能相关负性情绪的中期调节效果。方法采用多中心随机双盲对照试验设计,纳入41例乳腺癌术后伴轻中度负性情绪患者,即医院焦虑抑郁量表(...目的探讨揿针干预对乳腺癌术后患者下丘脑-垂体-肾上腺轴(Hypothalamic-pituitaryadrenal axis,HPA)功能相关负性情绪的中期调节效果。方法采用多中心随机双盲对照试验设计,纳入41例乳腺癌术后伴轻中度负性情绪患者,即医院焦虑抑郁量表(Hospital anxiety and depression scale,HADS)评分为1-14分,随机分为揿针组(n=18)与安慰剂揿针组(n=23)。干预组采用背俞穴揿针留置,对照组使用无针尖安慰揿针留置,每周更换2次,持续3周。主要结局指标为HADS评分,次要指标包括欧洲癌症研究与治疗组织生活质量问卷(European Organization for Research and Treatment of Cancer Quality of life questionnaire,EORTC QLQ-C30)及匹兹堡睡眠质量指数(Pittsburgh sleep quality index,PSQI),于基线、干预3周及随访5周评估。结果干预3周后,揿针组HADS焦虑评分较基线显著改善(t=-2.84,P=0.012),且与安慰剂组相比,组间差异具有统计学意义(t=-3.51,P=0.001),此效应持续至随访期。在生活质量方面,揿针组EORTC QLQ-C30评分在干预3周后即显著优于安慰剂组(t=-2.70,P=0.010),且此优势在随访期进一步扩大(46.4±7.09 vs.56.3±10.3,t=-3.56,P=0.001)。在睡眠质量方面,尽管干预结束时组间PSQI评分存在差异(P=0.040),但随访期间该差异无统计学意义(P=0.0765),提示睡眠改善效果未能持久维持。结论背俞穴揿针干预能持续、有效地缓解乳腺癌术后患者的焦虑情绪,并显著提升其生活质量,其作用机制可能与调节HPA轴功能有关。然而,该疗法对睡眠质量的改善作用较为短期,未来需结合多维度干预策略以巩固疗效。展开更多
基金National Natural Science Foundation of China(51504138,51674118,52271177)Hunan Provincial Natural Science Foundation of China(2023JJ50181)Supported by State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(P2024-022)。
文摘To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.
基金co-supported by the Chinese NSFC funds (Nos.41272127, 40972025, 40571017)IGCP580
文摘This study carried out comprehensive analysis on sedimentology, magnetic susceptibility （7of） and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change information during the 129.14-122.98 Ma interval. Based on the results of the Xlf and of the redness （a＊）, the section can be divided into two segments： （1） 129.14-126.3 Ma, with the lowest Xlf values and strongly variable relatively high values of redness and （2） 126.3-122.98 Ma, with high Elf values and relatively low redness. Analysis of the lithology and facies as well as the magnetic minerals and their contents points to a detrital origin of the magnetic minerals and this allow us to interpret the relationship between magnetic susceptibility variations and climate changes. Our study shows that the climate was significantly dry and hot during the whole studied interval although the interval between 126.3 Ma and 122.98 was a little bit cooler with increased humidity.
文摘目的探讨揿针干预对乳腺癌术后患者下丘脑-垂体-肾上腺轴(Hypothalamic-pituitaryadrenal axis,HPA)功能相关负性情绪的中期调节效果。方法采用多中心随机双盲对照试验设计,纳入41例乳腺癌术后伴轻中度负性情绪患者,即医院焦虑抑郁量表(Hospital anxiety and depression scale,HADS)评分为1-14分,随机分为揿针组(n=18)与安慰剂揿针组(n=23)。干预组采用背俞穴揿针留置,对照组使用无针尖安慰揿针留置,每周更换2次,持续3周。主要结局指标为HADS评分,次要指标包括欧洲癌症研究与治疗组织生活质量问卷(European Organization for Research and Treatment of Cancer Quality of life questionnaire,EORTC QLQ-C30)及匹兹堡睡眠质量指数(Pittsburgh sleep quality index,PSQI),于基线、干预3周及随访5周评估。结果干预3周后,揿针组HADS焦虑评分较基线显著改善(t=-2.84,P=0.012),且与安慰剂组相比,组间差异具有统计学意义(t=-3.51,P=0.001),此效应持续至随访期。在生活质量方面,揿针组EORTC QLQ-C30评分在干预3周后即显著优于安慰剂组(t=-2.70,P=0.010),且此优势在随访期进一步扩大(46.4±7.09 vs.56.3±10.3,t=-3.56,P=0.001)。在睡眠质量方面,尽管干预结束时组间PSQI评分存在差异(P=0.040),但随访期间该差异无统计学意义(P=0.0765),提示睡眠改善效果未能持久维持。结论背俞穴揿针干预能持续、有效地缓解乳腺癌术后患者的焦虑情绪,并显著提升其生活质量,其作用机制可能与调节HPA轴功能有关。然而,该疗法对睡眠质量的改善作用较为短期,未来需结合多维度干预策略以巩固疗效。
