期刊文献+
共找到6,055篇文章
< 1 2 250 >
每页显示 20 50 100
Aerothermal performance of turbine during flight cycle based on fluid-thermal-structure multidisciplinary coupling method
1
作者 Yunda ZHANG Zhengping ZOU +2 位作者 Chao FU Yifan WANG Jun ZENG 《Chinese Journal of Aeronautics》 2026年第1期35-54,共20页
The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Rel... The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation. 展开更多
关键词 Flight cycle Fluid-thermal-structure Multidisciplinary coupling Quasi-steady-state TURBINE
原文传递
Durability of SAP-modified Fully Recycled Concrete under Freeze-Thaw Cycles
2
作者 XING Zhengguang PENG Erxing +3 位作者 ZHANG Mingyi PEI Wansheng HU Xiaoying SUN Haoyue 《Journal of Wuhan University of Technology(Materials Science)》 2026年第1期179-188,共10页
This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw ... This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance. 展开更多
关键词 Recycled concrete SAP freeze-thaw cycle pore structure DURABILITY
原文传递
Forecasting solar cycles using the time-series dense encoder deep learning model
3
作者 Cui Zhao Shangbin Yang +1 位作者 Jianguo Liu Shiyuan Liu 《Astronomical Techniques and Instruments》 2026年第1期43-54,共12页
The solar cycle(SC),a phenomenon caused by the quasi-periodic regular activities in the Sun,occurs approximately every 11 years.Intense solar activity can disrupt the Earth’s ionosphere,affecting communication and na... The solar cycle(SC),a phenomenon caused by the quasi-periodic regular activities in the Sun,occurs approximately every 11 years.Intense solar activity can disrupt the Earth’s ionosphere,affecting communication and navigation systems.Consequently,accurately predicting the intensity of the SC holds great significance,but predicting the SC involves a long-term time series,and many existing time series forecasting methods have fallen short in terms of accuracy and efficiency.The Time-series Dense Encoder model is a deep learning solution tailored for long time series prediction.Based on a multi-layer perceptron structure,it outperforms the best previously existing models in accuracy,while being efficiently trainable on general datasets.We propose a method based on this model for SC forecasting.Using a trained model,we predict the test set from SC 19 to SC 25 with an average mean absolute percentage error of 32.02,root mean square error of 30.3,mean absolute error of 23.32,and R^(2)(coefficient of determination)of 0.76,outperforming other deep learning models in terms of accuracy and training efficiency on sunspot number datasets.Subsequently,we use it to predict the peaks of SC 25 and SC 26.For SC 25,the peak time has ended,but a stronger peak is predicted for SC 26,of 199.3,within a range of 170.8-221.9,projected to occur during April 2034. 展开更多
关键词 Solar cycle Forecasting TIDE Deep learning
在线阅读 下载PDF
Fluid mechanics approach to assess airflow dynamics during the respiratory cycle in a child nasal airway with adenoid hypertrophy
4
作者 Zahid Ullah Khan Xizhuo Jiang +1 位作者 Jingliang Dong Xiaodong Wang 《Acta Mechanica Sinica》 2026年第1期162-177,共16页
The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow ... The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow mechanics in the child’s nasal upper airway with adenoid hypertrophy,with an adenoid nasopharyngeal ratio(AN of 0.9),under cyclic inhalation and exhalation.An inlet respiratory cycle with three different flow rates(3.2 L/min calm breathing,8.6 L/min normal breathing,and 19.3 L/min intensive breathing)was simulated by using the computational fluid dynamics approach.To better capture the interaction between airflow and the flexible airway tissue,fluid-structure interaction analysis was performed at the normal breathing rate.Comparing the airflow dynamics during inhalation and exhalation,the pressure drops,nasal resistance,and wall shear stress show significant differences in the nasopharyngeal region for all different flow rates.This observation suggests that the inertial effect associated with the transient flow is important during exhalation and inhalation.Furthermore,the considerable temporal variation in flow rate distribution across a specific cross-section of the nasal airway highlights the critical role of transient data in virtual surgery planning and data for clinical decisions. 展开更多
关键词 Computational fluid dynamics Child nasal airway Nasal breathing cycle Flow mechanics Nasal resistance Pressure drop Wall shear stress
原文传递
The extract of Cyperus rotundus rhizome promotes hair growth and modulates hair cycle in vivo and in vitro
5
作者 Yunwei Hu Keke Hu +4 位作者 Jiaying Liang Xingjiang Zhang Huijuan Li Jianxin Wu Qing Huang 《Chinese Journal of Natural Medicines》 2026年第2期203-214,共12页
Hair loss,a multifactorial disorder characterized by follicular miniaturization and excessive shedding,significantly impairs psychological well-being and quality of life.Cyperus rotundus rhizome(CR),a traditional Chin... Hair loss,a multifactorial disorder characterized by follicular miniaturization and excessive shedding,significantly impairs psychological well-being and quality of life.Cyperus rotundus rhizome(CR),a traditional Chinese medicine used for various ailments,has not been evaluated for efficacy in treating hair loss.This study presents the first comprehensive assessment of the hair growth-promoting effects of ethanol extract from CR on mouse primary dermal papilla cells(MDPCs)and human immortalized hair DPCs(IHHDPCs),employing cell counting kit-8(CCK-8),scratch assay,reverse transcription-quantitative polymerase chain reaction(RT-q PCR),and Western blot(WB).CR treatment activated the Wnt/β-Catenin signaling pathway by upregulating Wnt10b,increasingβ-Catenin protein levels and promoting its nuclear translocation,while simultaneously downregulating transforming growth factor-beta 1(TGF-β1),BMP4,and dickkopf-related protein 1(DKK1)in MDPCs.These molecular changes enhanced cell proliferation and increased secretion of key growth factors—insulin-like growth factor 1(IGF1),keratinocyte growth factor(KGF),and vascular endothelial growth factor(VEGF)—thereby stimulating hair growth and prolonging the anagen phase,which was confirmed in an ex vivo hair follicle(HF)organ culture model.Chromatographic analysis identified the petroleum ether fraction(CRP),enriched in sesquiterpenes,as the primary bioactive component.Both CR and CRP promoted IHHDPC proliferation,migration,and growth factor expression through activation of the Wnt/β-Catenin pathway,with CRP exhibiting superior bioactivity.Furthermore,both treatments stimulated HF cycling,increased follicular density,and upregulated Ki67 andβ-Catenin expression in the dorsal skin of C57BL/6 mice.Collectively,these findings demonstrate that CR and CRP promote hair growth and modulate the hair cycle via enhancement of Wnt/β-Catenin signaling,providing a scientific basis for the potential clinical application of C.rotundus rhizomes in hair loss therapy and the development of related pharmaceuticals or cosmetics. 展开更多
关键词 Cyperus rotundus Hair growth Hair cycle WNT/Β-CATENIN
原文传递
Study on the strength deterioration characteristics and microscopic mechanisms of moraine soil under freeze-thaw cycles
6
作者 Peng-fei Wang Ming-li Li +3 位作者 Ming Chang Jun-lin Jiang Fan Yang Zhi-qiang Zuo 《Journal of Groundwater Science and Engineering》 2026年第1期15-31,共17页
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,... To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau. 展开更多
关键词 Moraine soil in the Qinghai-Xizang Plateau F-T cycle Standard triaxial tests soil strength degradation Mohr-Coulomb criterion Microscopic pore structure
在线阅读 下载PDF
Oxygen-Pressure Protocol Breaking Cycle Limit of Continuously Reversible Lithium-Oxygen Batteries
7
作者 Xinhang Cui Fenglong Xiao +10 位作者 Guoliang Zhang Zhangliu Tian Qingshan Bao Yanlu Li Deliang Cui Qilong Wang Feng Dang Wei Chen Haohai Yu Huaijin Zhang Gang Lian 《Nano-Micro Letters》 2026年第5期391-404,共14页
Lithium-oxygen(Li-O_(2))battery is favored among“beyond lithiumion”technologies for sustainability because of its exceptional energy density.Major impediments are the poor cycle stability and grievous capacity degra... Lithium-oxygen(Li-O_(2))battery is favored among“beyond lithiumion”technologies for sustainability because of its exceptional energy density.Major impediments are the poor cycle stability and grievous capacity degradation at high current densities.We address these issues by a“killing two birds with one stone”O_(2)-pressure protocol.It first resolves efficient O_(2) mass transport at high rates..The accelerated reaction kinetics optimizes the composition and growth pathway of discharge products.This protocol secondly achieves protection of Li anodes via densifying corrosion layers on them.Consequently,the battery delivers both ultrahigh discharge capacity(>9,000 mAh g^(-1))at 3,000 mA g^(-1) and excellent cycling stability.Under a dual-strategy effect of high-pressure O_(2) and artificial protection layers,the battery actualizes over 11-fold increase in cycle life of 5,170 h(2,585 cycles).The strategy opens avenues for advancing Li-O_(2) batteries towards practical application and confers the extension to other gas-based batteries. 展开更多
关键词 Li-O_(2)batteries O_(2)pressure cycle life Li anode protection Rate performance
在线阅读 下载PDF
Experimental study on damage evolution and failure precursor characteristics of granite under thermal shock cycles
8
作者 Zhenjiang Huang Mingxuan Shen +5 位作者 Yu Zhao Chaolin Wang Jing Bi Yongfa Zhang Shuang Dang Yuhang Zhao 《International Journal of Mining Science and Technology》 2026年第1期125-148,共24页
Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens un... Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions,employing acoustic emission monitoring,digital image correlation,and three-dimensional scanning technology.A systematic analysis was conducted on the patterns of damage evolution,failure precursor,and response mechanisms under combined thermal and cyclic loading.Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count,with temperature having a more pronounced effect than cycle count.Notably,damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400℃ and stabilizes after 5 thermal cycles.Fracture surfaces evolve from initially planar to rugged morphologies,with peak-valley height differences at 600℃ being approximately three times greater than those at 200℃.Furthermore,based on acoustic emission energy entropy analysis,we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure.These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering. 展开更多
关键词 GRANITE Thermal shock cycles Acoustic emission Thermal damage Failure precursor
在线阅读 下载PDF
Effects of freeze-thaw cycles on aggregate stability of sandy loam on the Eastern Qinghai-Tibet Plateau
9
作者 FENG Xiao DUN Yaoquan +2 位作者 QU Jianjun TIAN Qin DONG Lili 《Journal of Mountain Science》 2026年第1期417-433,共17页
Freeze-thaw cycles(FTCs)have an important effect on soil aggregate stability by altering soil structures,thereby influencing soil wind and water erosion on the eastern Qinghai-Tibet Plateau.However,the effects of FTCs... Freeze-thaw cycles(FTCs)have an important effect on soil aggregate stability by altering soil structures,thereby influencing soil wind and water erosion on the eastern Qinghai-Tibet Plateau.However,the effects of FTCs on the stability of these soils remain unclear.Here,we conducted freeze-thaw simulations in laboratory to investigate the effects of FTCs(0 to 15 cycles)on the wet-and dry-sieving aggregate stability of undisturbed sandy loam from Maqu county,which was treated with different initial soil moisture contents(1%to 25%in increments of 4%)and initial aggregate diameters(<2,2-5,5-10,and 10-15 mm).Results show that soil aggregates with initial diameters larger than 2 mm exhibit higher soil organic carbon contents(1.45%-1.57%)and silt contents(34.63%-35.52%)than those smaller than 2 mm(0.93%and 31.38%,respectively).The stability of both wet-and dry-sieving aggregates increases with larger initial diameters.Increasing initial soil moisture content from 1%to 25%reduces aggregate stability,with reductions of 2.4%-88.0%for wet-sieving aggregates and 2.1%-25.5%for dry-sieving aggregates(>2 mm).With increasing FTCs,wet-sieving aggregate(>2 mm)stability exhibits a fluctuating upward trend,with increases of 79.2%-87.4%after 15 FTCs,while dry-sieving aggregate(>2 mm)stability decreases significantly(5.7%-21.7%)upon the first FTC and remains unchanged thereafter.The stability of both the wet-and dry-sieving aggregates smaller than 2 mm remains unchanged with increasing FTCs(p>0.05).SOC content decreases by 22.3%on average with increasing FTCs from 1 to 15 and shows no significant correlations with wet-and dry-sieving aggregate stability.Higher silt content(r=0.39,p<0.05)and lower sand content(r=-0.38,p<0.05)enhances the wet-sieving aggregate stability of sandy loam.Frequent FTCs tend to improve wet-sieving aggregate stability but reduce dry-sieving aggregate stability in the sandy loam.The findings provide certain guidance for preventing freeze-thaw-induced wind erosion. 展开更多
关键词 Freeze-thaw cycles Sandy loam Soil aggregate stability Initial aggregate diameter Soil erosion Soil organic carbon
原文传递
一种带有比较器交错的2-bit/cycle高速SAR ADC
10
作者 费秘 岳宏卫 韦善于 《微电子学》 北大核心 2025年第6期941-948,共8页
针对传统2-bit/cycle逐次逼近模数转换器(SAR ADC)中需要2^(N)个额外单位电容来提高速度的问题,基于CMOS 40 nm工艺提出了一种带有比较器交错的2-bit/cycle高速SAR ADC。该结构通过在最后一个比较周期自动切换不同尺寸大小的比较器来等... 针对传统2-bit/cycle逐次逼近模数转换器(SAR ADC)中需要2^(N)个额外单位电容来提高速度的问题,基于CMOS 40 nm工艺提出了一种带有比较器交错的2-bit/cycle高速SAR ADC。该结构通过在最后一个比较周期自动切换不同尺寸大小的比较器来等效减小参考电压的方法,将电容式数模转换器(CDAC)单位电容的使用量降低50%。此外,提出的比较器速度反馈系统能够在输入电压差较低时提高比较器的速度,并通过在采样保持电路中采用两段栅压自举和引入补偿电容的方法来降低噪声与失真。仿真结果表明,该ADC的分辨率为10 bit,采样频率为700 MS/s,在Nyquist输入频率下的SNDR为55.05 dB,SFDR为67.27 dB,整体功耗为2.91 mW,Walden FoM为9.20 fJ/conv.。 展开更多
关键词 2-bit/cycle 速度反馈 高速 SAR ADC 比较器交错
原文传递
Carbon emissions in China’s steel industry from a life cycle perspective:Carbon footprint insights 被引量:9
11
作者 Xiaocong Song Shuai Du +5 位作者 Chenning Deng Peng Shen Minghui Xie Ci Zhao Chen Chen Xiaoyu Liu 《Journal of Environmental Sciences》 2025年第2期650-664,共15页
China is the most important steel producer in the world,and its steel industry is one of themost carbon-intensive industries in China.Consequently,research on carbon emissions from the steel industry is crucial for Ch... China is the most important steel producer in the world,and its steel industry is one of themost carbon-intensive industries in China.Consequently,research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals.We constructed a carbon dioxide(CO_(2))emission model for China’s iron and steel industry froma life cycle perspective,conducted an empirical analysis based on data from2019,and calculated the CO_(2)emissions of the industry throughout its life cycle.Key emission reduction factors were identified using sensitivity analysis.The results demonstrated that the CO_(2)emission intensity of the steel industry was 2.33 ton CO_(2)/ton,and the production and manufacturing stages were the main sources of CO_(2)emissions,accounting for 89.84%of the total steel life-cycle emissions.Notably,fossil fuel combustion had the highest sensitivity to steel CO_(2)emissions,with a sensitivity coefficient of 0.68,reducing the amount of fossil fuel combustion by 20%and carbon emissions by 13.60%.The sensitivities of power structure optimization and scrap consumption were similar,while that of the transportation structure adjustment was the lowest,with a sensitivity coefficient of less than 0.1.Given the current strategic goals of peak carbon and carbon neutrality,it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies,increase the ratio of scrap steel to steelmaking,and build a new power system. 展开更多
关键词 Iron and steel industry Life cycle Carbon dioxide(CO_(2))emissions Carbon footprint China
原文传递
鸭瘟病毒Cycleave荧光PCR检测方法的建立
12
作者 于新友 李天芝 苗立中 《中国动物传染病学报》 北大核心 2025年第2期106-110,共5页
为建立一种敏感、快速和特异的鸭瘟病毒(DPV)检测方法,本研究根据NCBI收录的DPV UL6基因序列,设计了1对特异性引物和1条Cycling探针,通过优化反应条件,建立了检测DPV的Cycleave荧光PCR检测方法。结果显示:该方法特异性高,不与其他常见... 为建立一种敏感、快速和特异的鸭瘟病毒(DPV)检测方法,本研究根据NCBI收录的DPV UL6基因序列,设计了1对特异性引物和1条Cycling探针,通过优化反应条件,建立了检测DPV的Cycleave荧光PCR检测方法。结果显示:该方法特异性高,不与其他常见鸭病病原体发生交叉反应,检测DPV灵敏度可达6.5拷贝/μL,批内与批间的变异系数均小于2%。研究表明,建立的DPV Cycleave荧光定量PCR方法特异性高、敏感性高、重复性好,可用于临床样品检测,为鸭瘟的诊断和防控奠定了基础。 展开更多
关键词 鸭瘟病毒 Cycling探针 cycleave荧光PCR 检测
在线阅读 下载PDF
Mechanical and microstructural properties of schist exposed to freezethaw cycles,dry-wet cycles,and alternating actions 被引量:2
13
作者 Jiajia Gao Jiajian Jin +5 位作者 Daguo Wang Shaogang Lei Jianguo Lu Huan Xiao Jinhe Li Huadong Li 《International Journal of Mining Science and Technology》 2025年第5期783-800,共18页
In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural prope... In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural properties of schist subjected to four conditions were investigated:freeze-thaw cycles in air(FTA),freeze-thaw cycles in water(FTW),dry-wet cycles(DW),and dry-wet-freeze-thaw cycles(DWFT).Uniaxial compressive strength(UCS),water absorption,ultrasonication,low-field nuclear magnetic resonance,and scanning electron microscopy analyses were conducted.The integrity attenuation characteristics of the longitudinal wave velocity,UCS,and elastic modulus were analyzed.The results showed that liquid water emerged as a critical factor in reducing the brittleness of schist.The attenuation function model accurately described the peak stress and static elastic modulus of schist in various media(R2>0.97).Different media affected the schist deterioration and half-life,with the FTW-immersed samples having a half-life of 28 cycles.Furthermore,the longitudinal wave velocity decreased as the number of cycles increased,with the FTW showing the most significant reduction and having the shortest half-life of 208 cycles.Moreover,the damage variables of compressive strength and elastic modulus increased with the number of cycles.After 40 cycles,the schist exposed to FTW exhibited the highest damage variables and saturated water content. 展开更多
关键词 SCHIST Mechanical property Microstructure Freeze-thaw cycles Dry-wet cycles
在线阅读 下载PDF
High cycle fatigue performance at 650℃and corresponding fracture behaviors of GH4169 joint produced by linear friction welding 被引量:2
14
作者 Shitong MA Xiawei YANG +6 位作者 Zhenguo GUO Yu SU Xinyuan HE Ju LI Jun TAO Bo XIAO Wenya LI 《Chinese Journal of Aeronautics》 2025年第1期622-637,共16页
GH4169 joints manufactured by Linear Friction Welding(LFW)are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue(HCF)performance at 650℃.The yield and ultimate tensile strengths are 58... GH4169 joints manufactured by Linear Friction Welding(LFW)are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue(HCF)performance at 650℃.The yield and ultimate tensile strengths are 582 MPa and 820 MPa,respectively.The HCF strength of joint reaches 400 MPa,which is slightly lower than that of Base Metal(BM),indicating reliable quality of this type of joint.The microstructure observation results show that all cracks initiate at the inside of specimens and transfer into deeper region with decrease of external stress,and the crack initiation site is related with microhardness of matrix.The Electron Backscattered Diffraction(EBSD)results of the observed regions with different distances to fracture show that plastic deformation plays a key role in HCF,and the Schmid factor of most grains near fracture exceeds 0.4.In addition,the generation of twins plays a vital role in strain concentration release and coordinating plastic deformation among grains. 展开更多
关键词 High cycle fatigue GH4169 superalloy Linear friction welding Fracture mechanism Microstructure evolution
原文传递
Hemispheric prediction of solar cycles 25 and 26 from multivariate sunspot time-series data via Informer models 被引量:2
15
作者 Jie Cao Tingting Xu +6 位作者 Linhua Deng Xueliang Zhou Xinhua Zhao Nanbin Xiang Fuyu Li Miao Wan Weihong Zhou 《Astronomical Techniques and Instruments》 2025年第1期16-26,共11页
Solar activity plays an important role in influencing space weather,making it important to understand numerous aspects of spatial and temporal variations in the Sun's radiative output.High-performance deep learnin... Solar activity plays an important role in influencing space weather,making it important to understand numerous aspects of spatial and temporal variations in the Sun's radiative output.High-performance deep learning models and long-term observational records of sunspot relative numbers are essential for solar cycle forecasting.Using the multivariate time series of monthly sunspot relative numbers provided by the National Astronomical Observatory of Japan and two Informer-based models,we forecast the amplitude and timing of solar cycles 25 and 26.The main results are as follows:(1)The maximum amplitude of solar cycle 25 is higher than the previous solar cycle 24 and the following solar cycle 26,suggesting that the long-term oscillatory variation of sunspot magnetic fields is related to the roughly centennial Gleissberg cyclicity.(2)Solar cycles 25 and 26 exhibit a pronounced Gnevyshev gap,which might be caused by two non-coincident peaks resulting from solar magnetic flux transported by meridional circulation and mid-latitude diffusion in the convection zone.(3)Hemispheric prediction of sunspot activity reveals a significant northsouth asynchrony,with activity level of the Sun being more intense in the southern hemisphere.These results are consistent with expectations derived from precursor methods and dynamo theories,and further provide evidence for internal changes in solar magnetic field during the decay of the Modern Maximum. 展开更多
关键词 Solar magnetic fields Solar cycle Deep learning
在线阅读 下载PDF
Qingqi Guxue Decoction induces S cell cycle arrest to inhibit replication of severe fever with thrombocytopenia syndrome virus 被引量:2
16
作者 Xixi Shi Zining Wang +5 位作者 Zixiang Liu Qinting Lin Mengqian Huang Tze Yean Lim Xiaoyan Li Tao Wang 《Virologica Sinica》 2025年第2期260-274,共15页
Severe fever with thrombocytopenia syndrome(SFTS)is a novel emerging acute infectious disease caused by severe fever with thrombocytopenia syndrome virus(SFTSV),characterized by high fever and thrombocytopenia.It has ... Severe fever with thrombocytopenia syndrome(SFTS)is a novel emerging acute infectious disease caused by severe fever with thrombocytopenia syndrome virus(SFTSV),characterized by high fever and thrombocytopenia.It has been proved that traditional Chinese medicine(TCM)has displayed definite therapeutic effects on viral hemorrhagic fever,indicating its potential to treat SFTS.In this study,SFTS-relative key targets were predicted via gene ontology(GO)analysis and kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis.Molecular docking was then used to select stable binders.Molecules matched TCMs were identified,and a new prescription,Qingqi Guxue decoction(QQGX),was formulated to clear heat and nourish blood,with a resulting drug composition network.We explored the optimal drug proportion for QQGX.Through an in-depth study of molecular mechanisms,we found that QQGX induces S phase arrest by promoting the degradation of cyclin A2(CCNA2)and cyclin-dependent kinase 2(CDK2),thereby inhibiting SFTSV replication.Finally,we verified the effectiveness and safety of QQGX based on the mouse liver bile duct organoid model infected with SFTSV.In summary,our study prepared a TCM decoction using the method of network pharmacology.This decoction has a significant inhibitory effect on the replication of SFTSV and provides a new treatment strategy for hemorrhagic fever with TCM. 展开更多
关键词 Qingqi Guxue decoction(QQGX) Severe fever with thrombocytopenia syndrome virus(SFTSV) Traditional Chinese medicine(TCM) Cell cycle S arrest
原文传递
Microstructure deterioration of sandstone under freeze-thaw cycles using CT technology:The effects of different water immersion conditions 被引量:2
17
作者 Bei Qiu Lifeng Fan Xiuli Du 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1599-1611,共13页
In cold regions,rock structures will be weakened by freeze-thaw cycles under various water immersion conditions.Determining how water immersion conditions impact rock deterioration under freeze-thaw cycles is critical... In cold regions,rock structures will be weakened by freeze-thaw cycles under various water immersion conditions.Determining how water immersion conditions impact rock deterioration under freeze-thaw cycles is critical to assess accurately the frost resistance of engineered rock.In this paper,freeze-thaw cycles(temperature range of-20℃-20℃)were performed on the sandstones in different water immersion conditions(fully,partially and non-immersed in water).Then,computed tomography(CT)tests were conducted on the sandstones when the freeze-thaw number reached 0,5,10,15,20 and 30.Next,the effects of water immersion conditions on the microstructure deterioration of sandstone under freezethaw cycles were evaluated using CT spatial imaging,porosity and damage factor.Finally,focusing on the partially immersed condition,the immersion volume rate was defined to understand the effects of immersion degree on the freeze-thaw damage of sandstone and to propose a damage model considering the freeze-thaw number and immersion degree.The results show that with increasing freeze-thaw number,the porosities and damage factors under fully and partially immersed conditions increase continuously,while those under non-immersed condition first increase and then remain approximately constant.The most severe freeze-thaw damage occurs in fully immersed condition,followed by partially immersed condition and finally non-immersed condition.Interestingly,the freeze-thaw number and the immersion volume rate both impact the microstructure deterioration of the partially immersed sandstone.For the same freeze-thaw number,the damage factor increases approximately linearly with increasing immersion volume rate,and the increasing immersion degree exacerbates the microstructure deterioration of sandstone.Moreover,the proposed model can effectively estimate the freeze-thaw damage of partially immersed sandstone with different immersion volume rates. 展开更多
关键词 Freeze-thaw cycles Water immersion condition Computed tomography(CT) Microstructure deterioration SANDSTONE
在线阅读 下载PDF
Performance of stabilized copper mine tailings with freeze-thaw and wet-dry seasonal cycles 被引量:2
18
作者 Uddav Ghimire Tejo V.Bheemasetti Hee-Jeong Kim 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1418-1428,共11页
Approximately 3.44 billion tons of copper mine tailings(MT)were produced globally in 2018 with an increase of 45%from 2010.Significant efforts are being made to manage these tailings through storage facilities,recycli... Approximately 3.44 billion tons of copper mine tailings(MT)were produced globally in 2018 with an increase of 45%from 2010.Significant efforts are being made to manage these tailings through storage facilities,recycling,and reuse in different industries.Currently,a large portion of tailings are managed through the tailing storage facilities(TSF)where these tailings undergo hydro-thermal-mechanical stresses with seasonal cycles which are not comprehensively understood.This study presents an investigative study to evaluate the performance of control and cement-stabilized copper MT under the influence of seasonal cycles,freeze-thaw(F-T)and wet-dry(W-D)conditions,representing the seasonal variability in the cold and arid regions.The control and cement-stabilized MT samples were subjected to a maximum of 12 F-T and 12 W-D cycles and corresponding micro-and-macro behavior was investigated through scanning electron microscope(SEM),volumetric strain(εvT,wet density(r),moisture content loss,and unconfined compressive strength(UCS)tests.The results indicated the vulnerability of Copper MT to 67%and 75%strength loss reaching residual states with 12 F-T and 8 W-D cycles,respectively.Whereas the stabilized MT retained 39%-55%and 16%-34%strength with F-T and W-D cycles,demonstrating increased durability.This research highlights the impact of seasonal cycles and corresponding strength-deformation characteristics of control and stabilized Copper MT in cold and arid regions. 展开更多
关键词 Copper mine tailings(MT) Stabilization Seasonal cycles Cold and arid region
在线阅读 下载PDF
Regulatory signatures involved in the cell cycle pathway contribute to egg production heterosis in chicken 被引量:1
19
作者 Jingwei Yuan Yuanmei Wang +8 位作者 Yanyan Sun Yunlei Li Aixin Ni Qin Li Hanhan Yang Xinying Xu Yunhe Zong Hui Ma Jilan Chen 《Journal of Animal Science and Biotechnology》 2025年第2期551-564,共14页
Background Crossbreeding is widely promoted as an efficient strategy to improve the productivity in agriculture.The molecular mechanism underlying heterosis for egg production is always intriguing in chicken.The trans... Background Crossbreeding is widely promoted as an efficient strategy to improve the productivity in agriculture.The molecular mechanism underlying heterosis for egg production is always intriguing in chicken.The transcriptional dynamic changes play a crucial role in the formation of heterosis,but little is known for the egg production traits.Results In present study,we measured the continuous manifestation of heterosis ranging from 2.67%to 10.24%for egg number in the crossbreds generated by reciprocal crossing White Leghorn and Beijing You chicken.The high-quality transcriptomes of ovary for purebreds(WW and YY)and crossbreds(WY and YW)in 5 laying stages were sequenced and integrated to identify regulatory networks relevant to the heterosis.We found highly conserved transcriptional features among 4 genetic groups.By using weighted gene co-expression network analysis(WGCNA),we obtained multiple gene co-expression modules that were significantly correlated with egg number for each group.The common KEGG pathways including apelin signaling pathway,cell cycle,ribosome,spliceosome and oxidative phosphorylation,were screened for the 2 crossbreds.Then,we identified consensus co-expression modules(CMs)that showed divergent expression pattern among crossbred(WY or YW)and purebreds(WW and YY).The hub genes of CMs were again overrepresented in the cell cycle pathway,and the crossbreds exhibited temporally complementary dominance of hub genes in the 5 laying stages.These results suggested that the crossbreds inherited from both parents to maintain the ovary function by cell cycle-related genes,contributing to the persistent heterosis for egg production.Furthermore,the dominant genes including MAD2L1,CHEK2 and E2F1 were demonstrated to function in ovarian follicle development and maturation and could be the candidate genes for egg production heterosis.Conclusion Our study characterized the dynamic profile of genome-wide gene expression in ovary and highlighted the role of dominant expression of cell cycle pathway genes in heterosis.These findings provided new insights for the molecular mechanism of egg production heterosis,which would facilitate the rational choice of suitable parents for producing crossbred chickens with higher egg production. 展开更多
关键词 Cell cycle CHICKEN DOMINANCE Egg production heterosis Ovary transcriptome WGCNA
在线阅读 下载PDF
Macro-micro tests of cohesive soil under varied normal and shear stresses subjected to drying-wetting cycles 被引量:1
20
作者 Fangyue Luo Ga Zhang Yangping Yao 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第9期5893-5905,共13页
The mechanical behavior of cohesive soil is sensitized to drying-wetting cycles under confinements.However,the hydromechanical coupling effect has not been considered in current constitutive models.A macro-micro analy... The mechanical behavior of cohesive soil is sensitized to drying-wetting cycles under confinements.However,the hydromechanical coupling effect has not been considered in current constitutive models.A macro-micro analysis scheme is proposed in this paper to investigate the soil deformation behavior under the coupling of stress and drying-wetting cycles.A new device is developed based on CT(computerized tomography)workstation to apply certain normal and shear stresses on a soil specimen during drying-wetting cycles.A series of tests are conducted on a type of loess with various coupling of stress paths and drying-wetting cycles.At macroscopic level,stress sensor and laser sensor are used to acquire stress and strain,respectively.The shear and volumetric strain increase during the first few drying-wetting cycles and then become stable.The increase of the shear stress level or confining pressure would cause higher increase rate and the value of shear strain in the process of drying-wetting cycles.At microscopic level,the grayscale value(GSV)of CT scanning image is characterized as the proportion of soil particles to voids.A fabric state parameter is proposed to characterize soil microstructures under the influence of stress and drying-wetting cycle.Test results indicate that the macroand micro-responses show high consistence and relevance.The stress and drying-wetting cycles would both induce collapse of the soil microstructure,which dominants degradation of the soil mechanical properties.The evolution of the macro-mechanical property of soil exhibits a positive linear relationship with the micro-evolution of the fabric state parameter. 展开更多
关键词 Cohesive soil Drying-wetting cycle Coupled loading Macro and micro test FABRIC
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部