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
针对印刷电路板(printed circuit board,PCB)缺陷检测过程中,因包含丰富的小目标缺陷,易出现漏检、误检现象,提出一种基于改进增强金字塔实时检测变换器(enhance pyramid real time detection transformer,EP-RTDETR)小目标PCB表面缺陷...针对印刷电路板(printed circuit board,PCB)缺陷检测过程中,因包含丰富的小目标缺陷,易出现漏检、误检现象,提出一种基于改进增强金字塔实时检测变换器(enhance pyramid real time detection transformer,EP-RTDETR)小目标PCB表面缺陷检测算法。首先,使用CSPDarknet替代原始骨干网络,以增强模型的特征提取能力;其次,设空间移动卷积门控线性单元(spatial moving point convolutional gated linear unit,SMPCGLU)模块改造C2f中的Bottleneck,增强了特征的门控调制能力和空间自适应性;再次,引入可学习位置编码,改进尺度交互机制,增强对不同位置信息的响应能力;然后,基于跨尺度特征融合模块(cross-scale feature-fusion module,CCFM)模块设计小目标增强金字塔结构(small object enhance pyramid,SOEP),增强的特征层和精细的特征融合使模型能够更准确地定位和识别小目标;最后,设计MPDIoU(minimum point distance-based intersection over union)+NWD(normalized wasserstein distance)loss,在加快模型收敛速度的同时更加关注小目标缺陷,回归结果更加准确。试验结果表明,相较于基准模型,准确率P提高了4.6%,召回率R提高了5.1%,平均精度均值mAP50提高了4.6%,参数量减少了16.38 M,浮点数减少了48.3,FPS提高了8.51 s,能够更好地进行小目标PCB表面缺陷检测。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。
文摘针对印刷电路板(printed circuit board,PCB)缺陷检测过程中,因包含丰富的小目标缺陷,易出现漏检、误检现象,提出一种基于改进增强金字塔实时检测变换器(enhance pyramid real time detection transformer,EP-RTDETR)小目标PCB表面缺陷检测算法。首先,使用CSPDarknet替代原始骨干网络,以增强模型的特征提取能力;其次,设空间移动卷积门控线性单元(spatial moving point convolutional gated linear unit,SMPCGLU)模块改造C2f中的Bottleneck,增强了特征的门控调制能力和空间自适应性;再次,引入可学习位置编码,改进尺度交互机制,增强对不同位置信息的响应能力;然后,基于跨尺度特征融合模块(cross-scale feature-fusion module,CCFM)模块设计小目标增强金字塔结构(small object enhance pyramid,SOEP),增强的特征层和精细的特征融合使模型能够更准确地定位和识别小目标;最后,设计MPDIoU(minimum point distance-based intersection over union)+NWD(normalized wasserstein distance)loss,在加快模型收敛速度的同时更加关注小目标缺陷,回归结果更加准确。试验结果表明,相较于基准模型,准确率P提高了4.6%,召回率R提高了5.1%,平均精度均值mAP50提高了4.6%,参数量减少了16.38 M,浮点数减少了48.3,FPS提高了8.51 s,能够更好地进行小目标PCB表面缺陷检测。
