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成釉细胞瘤的锥形束CT表现分析 被引量:5
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作者 罗晶晶 游梦 +2 位作者 文陈妮 许来青 郑广宁 《华西口腔医学杂志》 CAS CSCD 北大核心 2014年第4期373-377,共5页
目的对成釉细胞瘤的锥形束CT(CBCT)表现进行总结分析,为其临床诊断提供依据。方法对病理确诊的有完整CBCT影像资料的37例成釉细胞瘤病例进行回顾性分析,观察其不同CBCT表现。结果 37例资料中,31例为原发病例,6例为复发病例。CBCT表现:3... 目的对成釉细胞瘤的锥形束CT(CBCT)表现进行总结分析,为其临床诊断提供依据。方法对病理确诊的有完整CBCT影像资料的37例成釉细胞瘤病例进行回顾性分析,观察其不同CBCT表现。结果 37例资料中,31例为原发病例,6例为复发病例。CBCT表现:37例病变中,有36例(97.3%)为骨内型,其中多房型17例,单房型17例,蜂窝型2例;1例(2.7%)为骨外型,即软组织型。88.2%(15/17)多房型病变内见舌形嵴;34例(94.4%)颌骨呈唇颊侧或(和)腭舌侧膨隆,颌骨骨密质局部不连续。结论 CBCT检查能精确地反映成釉细胞瘤病变形态和内部结构,对其术前诊断及手术计划具有重要的指导意义。 展开更多
关键词 成釉细胞瘤 临床诊断
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下颌管分支的锥形束CT影像学分析 被引量:3
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作者 郭毅 张巧红 韩晓倩 《华西口腔医学杂志》 CAS CSCD 北大核心 2015年第2期158-160,共3页
目的运用锥形束CT(CBCT)分析下颌管分支发生的概率及其类型。方法选取拍摄CBCT影像的216例(女104例,男112例)患者为研究对象,对CBCT的下颌管分支影像进行观测并进行分类。结果 216例(432侧)患者中,39例(18.06%)50侧(11.57%)观测到下颌... 目的运用锥形束CT(CBCT)分析下颌管分支发生的概率及其类型。方法选取拍摄CBCT影像的216例(女104例,男112例)患者为研究对象,对CBCT的下颌管分支影像进行观测并进行分类。结果 216例(432侧)患者中,39例(18.06%)50侧(11.57%)观测到下颌管分支,其中女18例(17.31%),男21例(18.75%)。下颌管分支分为4类,第Ⅰ类17侧(3.94%),第Ⅱ类11侧(2.55%),第Ⅲ类20侧(4.63%),第Ⅳ类2侧(0.46%)。结论 CBCT对下颌管分支的检出率较高,口腔颌面外科医生在进行下颌手术时应注意下颌管分支这一解剖变异。 展开更多
关键词 下颌管分支 束CT 解剖学 放射影像学
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根尖周病中锥形束CT与根尖片识别病损差异的研究进展 被引量:6
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作者 高静 申静 《华西口腔医学杂志》 CAS CSCD 北大核心 2015年第2期209-213,共5页
随着影像学技术的进步,锥形束CT(CBCT)作为口腔临床检查的一种辅助手段,已经广泛应用于口腔医学的各个领域。它具有分辨率高、辐射量低、成像迅速、三维重建、失真小、对硬组织成像好等诸多优点。传统的根尖片是以二维图像的形式显示三... 随着影像学技术的进步,锥形束CT(CBCT)作为口腔临床检查的一种辅助手段,已经广泛应用于口腔医学的各个领域。它具有分辨率高、辐射量低、成像迅速、三维重建、失真小、对硬组织成像好等诸多优点。传统的根尖片是以二维图像的形式显示三维物体及其周围结构,仅显示重叠的近远中向骨质破坏,不能显示颊舌向骨质破坏。CBCT作为一种三维成像技术,可以从矢状位、冠状位和轴位显示组织的三维结构,克服了根尖片二维图像重叠、变形等缺陷。CBCT的三维成像技术较传统根尖片具有独特优势,与根尖片相比,CBCT在观察骨质结构和根尖骨质破坏方面具有更高的灵敏度。本文就CBCT与根尖片在根尖病损识别中的差异研究进展作一综述。 展开更多
关键词 根尖周病 根尖片
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Structural Color Dynamic Graphics Display Based on Microlens Array 被引量:1
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作者 LI Xue-han LIU Ling-zhi +1 位作者 HUANG Min LI Xiu 《印刷与数字媒体技术研究》 北大核心 2025年第2期162-168,共7页
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be... It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display. 展开更多
关键词 Structural color Microlens array Dynamic graphics display Moirémagnification Optical anti-counterfeiting
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Annealing temperature influence on forming limit curve and fracture toughness of aluminium/silver bilayer sheets 被引量:1
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作者 Mohammad Delshad GHOLAMI Mojtaba KHODAKARAMI +1 位作者 Mohammad ABADIAN Ramin HASHEMI 《Journal of Central South University》 2025年第1期34-48,共15页
This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the pre... This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities. 展开更多
关键词 cold roll bonding Ag/Al bilayer sheet mechanical properties forming limit curve fracture toughness
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Deformations and extensions of modified λ-differential Lie-Yamaguti algebras
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作者 TENG Wen PAN Yuewei 《中山大学学报(自然科学版)(中英文)》 北大核心 2025年第4期115-127,共13页
The modifiedλ-differential Lie-Yamaguti algebras are considered,in which a modifiedλ-differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modifiedλ-differential operator.First we introduce t... The modifiedλ-differential Lie-Yamaguti algebras are considered,in which a modifiedλ-differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modifiedλ-differential operator.First we introduce the representation of modifiedλ-differential Lie-Yamaguti algebras.Furthermore,we establish the cohomology of a modifiedλ-differential Lie-Yamaguti algebra with coefficients in a representation.Finally,we investigate the one-parameter formal deformations and Abelian extensions of modifiedλ-differential Lie-Yamaguti algebras using the second cohomology group. 展开更多
关键词 Lie-Yamaguti algebra modifiedλ-differential operator representation and cohomology one-parameter formal deformation Abelian extension
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The first discovery of non-avian dinosaur egg clutch(Macroolithus yaotunensis,Elongatoolithidae)from the Upper Cretaceous Qiupa Formation of Tantou Basin
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作者 ZHU Xu-Feng CHANG Fei +10 位作者 LI Yu ZHANG Xu-Huang GAO Dian-Song WANG Qiang QIU Rui WANG Xiao-Lin LIU Di JIA Song-Hai JIA Guang-Hui ZHANG Jian-Hua XU Li 《古脊椎动物学报(中英文)》 北大核心 2025年第2期159-172,共14页
The Upper Cretaceous of Tantou Basin in western Henan has yielded many vertebrate fossils,which are featured by several non-avian dinosaurs.Meanwhile,studies on their eggs were yet inadequate though many eggshells hav... The Upper Cretaceous of Tantou Basin in western Henan has yielded many vertebrate fossils,which are featured by several non-avian dinosaurs.Meanwhile,studies on their eggs were yet inadequate though many eggshells have been reported.The newly discovered material 41HⅤ0199 was excavated from the Upper Cretaceous Qiupa Formation in 2021.The block preserves eight complete eggs arranged in two partial rings that form a partial clutch,and there are some scattered eggshells preserved closely with the block,showing a concave-up to concave-down ratio of 54.5:45.5,which indicates that the scattered eggshells come from the clutch and the clutch had been partially broken before it was buried.Based on morphological and microstructural characteristics,the eggs and eggshells can be assigned to Macroolithus yaotunensis(Elongatoolithidae),an oospecies known to be related to oviraptorids,which leads Yulong mini to be its probable producer.Besides,some eggshells show microstructural signs indicating egg retention,which marks the second example of egg retention in the oofamily Elongatoolithidae. 展开更多
关键词 Tantou Basin Upper Cretaceous Qiupa Formation dinosaur egg Macroolithus
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First discovery of Neogene proboscidean fossils in southeast China
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作者 LI Chun-Xiao TANG Jian-Rong +7 位作者 WANG Shi-Qi WANG Lin-Chang ZHENG Ying-Kai DENG Ke LIN Min CHEN Run-Sheng ZHOU Guo-Wu CHEN Zhong-Yang 《古脊椎动物学报(中英文)》 北大核心 2025年第1期43-56,共14页
Stegolophodon is an age-informative genus of mammals that had a widespread distribution during the Neogene.This paper reports the discovery of Stegolophodon fossils from the Middle Miocene lower Fotan Formation at the... Stegolophodon is an age-informative genus of mammals that had a widespread distribution during the Neogene.This paper reports the discovery of Stegolophodon fossils from the Middle Miocene lower Fotan Formation at the Zhangpu locality,Fujian Province,China.This discovery represents the first evidence of Neogene proboscidean fossils in southeastern China.The newly found molar materials have low tooth crowns,very straight lophs/lophids,and an indistinct median sulcus.The mesoconelets and posterior cingulum are well-developed,while the second posterior pretrite central conule is significantly reduced.These specimens closely resemble Stegolophodon pseudolatidens in cheek tooth morphology,and can thus be attributed to the same species.This discovery fills a gap in the fossil record of large mammals in this region during the Neogene and provides valuable insights into the evolution of proboscideans and paleoenvironments. 展开更多
关键词 southeastern China Middle Miocene proboscidean Stegolophodon MORPHOLOGY
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Tuning support morphology to control alloy over PtCo/γ-Al_(2)O_(3) for the preferential oxidation of CO
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作者 SONG Lichuan ZHONG Liding +3 位作者 SHEN Jia LOU Yake GUO Yun WANG Li 《燃料化学学报(中英文)》 北大核心 2025年第1期96-105,共10页
The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influen... The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO. 展开更多
关键词 PtCo catalysts γ-Al_(2)O_(3) support morphology CO-PROX
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Porous spherical MnCo_(2)S_(4) as high⁃performance electrode material for hybrid supercapacitors
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作者 LUO Min WANG Xiaonan +3 位作者 ZHANG Yaqin PANG Tian LI Fuzhi SHI Pu 《无机化学学报》 北大核心 2025年第2期413-424,共12页
Porous spherical MnCo_(2)S_(4) was synthesized by a simple solvothermal method.Thanks to the well-designedbimetallic composition and the unique porous spherical structure,the MnCo_(2)S_(4) electrode exhibited an excep... Porous spherical MnCo_(2)S_(4) was synthesized by a simple solvothermal method.Thanks to the well-designedbimetallic composition and the unique porous spherical structure,the MnCo_(2)S_(4) electrode exhibited an exceptionalspecific capacitance of 190.8 mAh·g^(-1)at 1 A·g^(-1),greatly higher than the corresponding monometallic sulfides MnS(31.7 mAh·g^(-1))and Co_(3)S_(4)(86.7 mAh·g^(-1)).Impressively,the as-assembled MnCo_(2)S_(4)||porous carbon(PC)hybridsupercapacitor(HSC),showed an outstanding energy density of 76.88 Wh·kg^(-1)at a power density of 374.5 W·kg^(-1),remarkable cyclic performance with a capacity retention of 86.8% after 10000 charge-discharge cycles at 5 A·g^(-1),and excellent Coulombic efficiency of 99.7%. 展开更多
关键词 transitional metal sulfide SUPERCAPACITOR porous spherical structure
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A comprehensive study of the mechanical properties of rock-like materials for inelastic deformation model establishment
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作者 TRIMONOVA Mariia STEFANOV Yuri +1 位作者 DUBINYA Nikita BAKEEV Rustam 《地质力学学报》 北大核心 2025年第3期475-490,共16页
[Objective]The work is devoted to the study of irreversible deformation of artificial samples subjected to a set of standard experiments,with an aim to study their mechanical properties.The principal idea of the study... [Objective]The work is devoted to the study of irreversible deformation of artificial samples subjected to a set of standard experiments,with an aim to study their mechanical properties.The principal idea of the study is related to the preparation of an artificial material with an established constitutive behavior model.The existence of such a well-described material provides future opportunities to conduct controllable experiments on various mechanical processes in rock-like material for further development and validation of theoretical models used in rock mechanics.[Methods]A set of artificial samples was prepared for careful assessment through a number of loading tests.Experimental work was carried out to determine the rheological properties under conditions of triaxial compression tests and uniaxial tension.Triaxial loading tests are completed for 9 samples with varying radial stress levels(0-5 MPa).The samples are loaded up to the yield point with control of radial and volumetric strain.The experimental results,which contain the obtained interrelationships between axial and radial stresses and strains,are analyzed using the Drucker-Prager yield surface.Material hardening is taken into account through the non-associated plastic flow law with the cap model.Numerical modeling of sample loading is performed through the finite difference method.Mathematical model parameters are adjusted to minimize the discrepancy between numerical modeling results and experimental data.The design of a series of experimental studies necessary to determine all the parameters of the model has been studied.[Results]It is shown that the formulated mathematical model allows to reliably reproduce the inelastic behavior of the studied material,and it can be used to solve a set of applied problems in continuum mechanics,the problem of numerical simulation of hydraulic fracture growth in an elastoplastic medium in particular.It was found that for the entire range of applied lateral loads(0-5 MPa),the elastic limit varied from 2 to 4 MPa,after which the material began to behave plastically.It was also determined that at lateral loads≥3 MPa,compaction began to appear in the material beyond the yield point.Judging by the dependence of volumetric strains under a lateral load equal to 1.4 MPa,compaction should begin to appear even at lateral loads lower than 3 MPa.[Conclusion]Taking the plastic behavior of the material into account is necessary when moving on to modeling the hydraulic fracturing process in such a material,and the resultant plasticity parameters for the model material can be used for numerical modeling of elastoplastic deformation of the rock under consideration,including processes such as hydraulic fracture growth in a poroelastoplastic medium.[Significance]The suggested procedure to interpret results of experimental studies can be used for further numerical modeling of mechanical processes in rock masses with inelastic strain accumulation.This opportunity can increase the reliability of geomechanical models used for the optimization of hydrocarbon fields development. 展开更多
关键词 plastic deformation internal friction shear strength triaxial compression “Brazilian”test loading diagrams
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Identification of Ichthyoplankton Species in the East China Sea off the Coast of Zhoushan Archipelago Using An Integrated Strategy of Morphology and DNA Barcoding
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作者 LIANG Zibin JIANG Rijin +3 位作者 MCHURA Magati Tereza YIN Rui ZHOU Yongdong CHEN Yongjiu 《浙江海洋大学学报(自然科学版)》 2025年第1期49-59,共11页
The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term o... The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment. 展开更多
关键词 Zhoushan Archipelago ICHTHYOPLANKTON MORPHOLOGY DNA barcoding species diversity conservation management
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Analytical solutions of vertical load on deep rectangular jacked pipe considering tunnelling-induced ground loss
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作者 LI Jian-ye FANG Qian +4 位作者 LIU Xiang WANG Gan HUANG Jun DU Jian-ming ZHANG Zi-yi 《Journal of Central South University》 2025年第5期1855-1872,共18页
Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation... Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed. 展开更多
关键词 rectangular pipe jacking tunnel vertical load multi-layer parabolic soil arch model soil arching
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Enhancement of damage tolerance in Ti-6554 alloy through twinning and hetero-deformation induced strengthening synergy
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作者 FU Ming-zhu LUO Wei +7 位作者 LI Si-yun YAO Wen-xi PENG Shu-xian LIU Yi-kui LIU Ji-xiong ZHANG Ping-hui LIU Hui-qun PAN Su-ping 《Journal of Central South University》 2025年第3期744-759,共16页
Heterogeneous structure exhibits superiority in improving mechanical properties,whereas their effects on fatigue damage properties have rarely been studied.In this work,we employed a high-throughput gradient heat trea... Heterogeneous structure exhibits superiority in improving mechanical properties,whereas their effects on fatigue damage properties have rarely been studied.In this work,we employed a high-throughput gradient heat treatment method(757−857℃)to rapidly acquire the solution microstructure of the Ti-6554 alloy with different recrystallization degrees(0%,40%and 100%),followed by the same aging treatment.The results showed that theβ-hetero structure exhibited a yield strength(σ_(YS))of 1403 MPa,an increase of 6.7%,and a remarkable improvement in uniform elongation(UE)of 109.7%,reaching 6.5%,compared to the homogeneous structure.Interestingly,introducing a heterogeneous structure not only overcame the traditional trade-off between strength and ductility but also enhanced fatigue crack propagation(FCP)performance.During FCP process,β-hetero structure,through hetero-deformation induced(HDI)strengthening effects,promoted the accumulation of geometric necessary dislocations(GNDs)within coarseα_(S) phase,enabling faster attainment of the critical shear stress of twinning and increasing twinning density.This facilitated stress relief,improved plastic deformation in the crack tip zone,and increased the critical fast fracture threshold from 30.4 to 36.0 MPa·m^(1/2)showing an enlarged steady state propagation region.This study provides valuable insights on tailoring fatigue damage tolerance through heterogeneous structure for titanium alloys. 展开更多
关键词 Ti-6554 alloy fatigue crack propagation hetero-deformation induced(HDI)strengthening deformation induced nano-scale twins
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Surface structure and their environment-dependent stability of NaMn_(2)O_(4)
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作者 SUN Shun-ping SUN Hong-fei +2 位作者 WANG Yu-rui CHEN Li-yong JIANG Yong 《Journal of Central South University》 2025年第5期1697-1709,共13页
As cathode materials for alkali-ion batteries,sodium manganese oxides have been receiving considerable and continuous attention in recent decades.In this work,the structure and environment-dependent stability of NaMn_... As cathode materials for alkali-ion batteries,sodium manganese oxides have been receiving considerable and continuous attention in recent decades.In this work,the structure and environment-dependent stability of NaMn_(2)O_(4) surface were studied based on the first principles calculations.The surface stability diagram of NaMn_(2)O_(4) involving various different terminations of(100),(110)and(111)surfaces was constructed,and the stability of these different terminations could be compared as a function of chemical environment.It is found that the(100)-MnO and(111)-ONa terminations are two more stable terminations under the investigated chemical conditions.And the surface energies of(110)surfaces are negative under the investigated chemical potential,hence,(110)surfaces are unstable.The surface energy of NaMn_(2)O_(4) as a function of O chemical potential is also investigated under constant Na chemical potential.The structure relaxation indicates that the surface rumpling and surface reconstruction can affect the electronic structure of the surface,thereby reducing surface energy and stabilizing the surface.Furthermore,the Wulff shape of NaMn_(2)O_(4) was also constructed based on Gibbs-Wulff theorem. 展开更多
关键词 NaMn_(2)O_(4) first principles SURFACE Wulff construction structure
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Abnormal texture and sensitivity to strain rate during hot-tension of Mg alloy sheets
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作者 ZHANG Hong-yang NIE Hui-hui +1 位作者 XU Xiong LIANG Wei 《Journal of Central South University》 2025年第3期991-1007,共17页
The deformation behavior of hot-rolled AZ31 magnesium(Mg)alloy sheet was analyzed when subjected to uniaxial tension along its normal direction at temperatures ranging from 100 to 400℃and strain rates ranging from 0.... The deformation behavior of hot-rolled AZ31 magnesium(Mg)alloy sheet was analyzed when subjected to uniaxial tension along its normal direction at temperatures ranging from 100 to 400℃and strain rates ranging from 0.5 to 100 mm/min.Based on the stress−strain curves and the dynamic material model,the hot processing map was established,which demonstrates that the power dissipation factor(η)is the most sensitive to strain rate at 400℃via absorption of dislocations.At 400℃,sample at 0.5 mm/min possessesηof 0.89 because of its lower kernel average misorientation(KAM)value of 0.51,while sample at 100 mm/min possessesηof 0.46 with a higher KAM value of 1.147.In addition,the flow stress presents a slight decrease of 25.94 MPa at 10 mm/min compared to that at 100 mm/min and 100℃.The reasons are twofold:a special~34°texture component during 100℃-100 mm/min favoring the activation of basal slip,and dynamic recrystallization(DRX)also providing softening effect to some extent by absorbing dislocations.Difference in activation of basal slip among twin laminas during 100℃-100 mm/min results in deformation inhomogeneity within the grains,which generates stress that helps matrix grains tilt to a direction favorable to basal slip,forming the special~34°texture component. 展开更多
关键词 Mg alloy sheet hot deformation TWINNING abnormal texture strain rate
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Atomic-scale understanding of martensitic transformation and transition-induced twinning in deformed Fe-Mn alloys
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作者 ZHANG Hong-bo LI Hong-kui +2 位作者 OU Xiao-qin SHEN Jie SONG Min 《Journal of Central South University》 2025年第4期1211-1222,共12页
In the present study,molecular dynamic simulation(MD)was used to investigate the plastic deformation process of the Fe-Mn alloys with different Mn contents.The influences of Mn contents ranging from 10%to 30%(at%)on t... In the present study,molecular dynamic simulation(MD)was used to investigate the plastic deformation process of the Fe-Mn alloys with different Mn contents.The influences of Mn contents ranging from 10%to 30%(at%)on the deformation behavior and the controlling mechanism of the Fe-base alloys were analyzed.The results show that phase transformations and{112}<111>_(BCC)deformation twinning occur in all Fe-Mn alloys but follow different deformation paths.In the Fe-10%Mn alloy the deformation twinning mechanism obeys the FCC-related path,the Fe-20%Mn alloy involves both the FCC-and HCP-related paths,and the deformation of the Fe-30%Mn alloy is dominated by the HCP-related twinning path.The addition of Mn can increase the stacking fault energy and retard the activation of slip systems as well as the formation of stacking faults.Thus,a higher content of Mn can delay the FCC®ε-martensite and the subsequentε-martensite®BCC phase transition at the intersection of twoε-martensitic bands.Therefore,the addition of Mn alloying element increases the yield strength and reduces the elastic modulus of the Fe-Mn alloys.The formation of deformation twins will contribute to the work-hardening effect and delay the necking and fracture of alloys.It is expected that the results in the present study will provide theoretical reference for the design and optimization of high-performance steels. 展开更多
关键词 Fe-Mn steel tensile deformation molecular dynamics simulation phase transformation
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Revealing laws of element diffusion and hot deformation characteristics during homogenization process of Alloy 625 Plus
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作者 DU Shu-yang DONG Yan-wu +2 位作者 JIANG Zhou-hua MEDOVAR Lev STOVPCHENKO Ganna 《Journal of Central South University》 2025年第7期2349-2363,共15页
Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during hom... Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during homogenization and the hot deformation behavior of the homogenized ingot were investigated in this study.The results indicate that:(1)the solidified ingot exhibits a typical dendritic microstructure,and significant element segregation occurs,leading to the presence of Ti,Nb,and Mo-rich precipitates in the interdendritic region;(2)Following homogenization,the degree of element segregation in the ingot is significantly reduced.The diffusion coefficients(D)of Ti,Nb,and Mo under various homogenization conditions were calculated.Subsequently,the diffusion constants(D_(0))and activation energies(Q)of Ti,Nb,and Mo were obtained to be 0.01432,0.00397 and 0.00195 cm^(2)/s and 244.851,230.312,and 222.125 kJ/mol,respectively.Finally,the diffusion kinetics formulas for Ti,Nb,and Mo in Alloy 625 Plus were established.After homogenization at 1220℃for 8 h,the alloy exhibits low deformation resistance,a high degree of recrystallization,and optimal deformation coordination ability.Therefore,this represents a rational single-stage homogenization process. 展开更多
关键词 solidification microstructure MICROSEGREGATION HOMOGENIZATION diffusion kinetics hot deformation
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Deformation mechanism of a novel pipe-roof composite slab:An experimental and theoretical investigation
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作者 LU Bo JIA Peng-jiao +3 位作者 ZHAO Wen NI Peng-peng BAI Qian CHENG Cheng 《Journal of Central South University》 2025年第3期1044-1059,共16页
Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space developmen... Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space development. Whilst the load-bearing of pipe-roof structures has been the subject of much research, uncertainties of deformation mechanism and the derivation of reliable calculation methods remain a challenge. For efficient design and wider deployment, this paper presents a bidirectional bending test to investigate the bending stiffnesses, load capacities and deformation mechanisms. The results show that the STS specimens exhibit good ductility and experience bending failure, and their deformation curves follow a half-sine wave upon loading. On this basis, the development of an STS composite slab deformation prediction model is proposed, along with the estimation for its bending stiffness. Theoretical predictions are shown to be in good agreement with the experimental measurements, with a maximum error of less than 15%. The outcomes of this investigation can provide references for the design and application of STS structures. 展开更多
关键词 steel tube slab deformation characteristics bending stiffness theoretical model
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Effect of hot deformation on grain structure and quench sensitivity in 7085 aluminum alloy
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作者 LI Cheng-bo ZHAO Cai +2 位作者 CAO Pu-li ZHU Dai-bo XIAO Bo 《Journal of Central South University》 2025年第4期1223-1236,共14页
The effect of hot deformation on the quench sensitivity of the 7085 alloy was studied through hardness testing and microstructure characterization.The findings indicate that hot deformation enhances the quench sensiti... The effect of hot deformation on the quench sensitivity of the 7085 alloy was studied through hardness testing and microstructure characterization.The findings indicate that hot deformation enhances the quench sensitivity of the 7085 alloy,with the hardness difference between water quenching and air cooling increasing from 5.4%(before hot deformation)to 10.4%(after hot deformation).In the undeformed samples,the Al3Zr particles within the grains exhibit better coherent with the Al matrix.During slow quenching,only theηphase is observed on Al3Zr particles and at the grain boundaries.Hot deformation leads to a mass of recrystallization and the formation of subgrains with high dislocation density.This results in an increase in the types,quantities,and sizes of heterogeneous precipitates during quenching.In the slow quenching process,high angle grain boundaries are best for the nucleation and growth of theηphase.Secondly,a substantial quantity ofηand T phases precipitate on the non-coherent Al3Zr phase within the recrystallized grains.The locations with high dislocation density subgrains(boundaries)serve as nucleation positions for theηand T phases precipitating.Additionally,the Y phase is observed to precipitate at dislocation sites within the subgrains. 展开更多
关键词 hot deformation 7085 aluminum alloy MICROSTRUCTURE heterogeneous precipitation quench sensitivity
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