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On Wiener Index of Power of Paths and Cycles
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作者 LIU Sai-hua LI Xiao-rong 《Chinese Quarterly Journal of Mathematics》 2025年第1期49-58,共10页
The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their dista... The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2. 展开更多
关键词 Wiener index kth power of a path kth power of a cycle
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Regulatory signatures involved in the cell cycle pathway contribute to egg production heterosis in chicken
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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
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Chemokines and PI3K/AKT signaling pathway mediate the spontaneously ruptured hepatocellular carcinoma through the regulation of the cell cycle
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作者 Yan Zhang Yang-Liu Zhou +4 位作者 Na Xu Tao Meng Zhen-Zhen Wang Fa-Ming Pan Li-Xin Zhu 《Hepatobiliary & Pancreatic Diseases International》 2025年第5期511-526,共16页
Background:The incidence of spontaneously ruptured hepatocellular carcinoma(srHCC)has been shown to significantly elevate mortality rates.However,the precise mechanisms underlying srHCC remain poorly understood.Method... Background:The incidence of spontaneously ruptured hepatocellular carcinoma(srHCC)has been shown to significantly elevate mortality rates.However,the precise mechanisms underlying srHCC remain poorly understood.Methods:Analysis was conducted on the data of 198 hepatocellular carcinoma(HCC)patients to inves-tigate the factors contributing to srHCC.The clinical data of 33 transcriptome HCC patients were served for verification.An in-depth transcriptome analysis was conducted to investigate the distinctions between 26 cases of srHCC and 35 cases of non-ruptured hepatocellular carcinoma(nrHCC).Weighted Gene Co-expression Network Analysis(WGCNA)tool was utilized to develop a gene co-expression network.Gene ontology(GO)and Kyoto encyclopedia of genes and genomes(KEGG)pathways enrichment,and protein-protein interaction(PPI)network were carried out.The corresponding samples for spontaneously rup-tured hepatocellular carcinoma tissue(srHCC-T)and ruptured hepatocellular carcinoma paracancerous tissue(srHCC-P)were selected for verification.Transcriptional data were validated through reverse tran-scription quantitative polymerase chain reaction(RT-qPCR).Immunofluorescence(IF),immunohistochem-istry(IHC)and Western blot were used to detect the protein expression.Results:Our results showed that white blood cell(WBC)and monocyte levels were significant inde-pendent risk factors for srHCC(P<0.05).There was a strong association between the srHCC-T and the expression of cell cycle-related genes BUB1B and macrophage function-related gene MACRO.Furthermore,chemokines and the PI3K/AKT signaling pathway play a crucial role in regulating the cell cycle process through a complex network of interactions,ultimately impacting the occurrence of srHCC.Conclusions:Our study confirms that chemokines and the PI3K/AKT signaling pathway mediate the occur-rence of HCC rupture by regulating the cell cycle.We provide a theoretical basis for the clinical treatment of srHCC. 展开更多
关键词 Spontaneously ruptured hepatocellular carcinoma Non-ruptured hepatocellular carcinoma TRANSCRIPTOME Cell cycle CHEMOKINES
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基于改进CycleGAN的小样本玉米病害图像扩充方法
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作者 李艳玲 张博翔 +3 位作者 李飞涛 Bacao Fernando 司海平 陈丽娜 《华中农业大学学报》 北大核心 2025年第5期198-207,共10页
针对玉米病害图像识别任务存在数据集获取困难、样本不足及不同类别病害样本不均衡等问题,设计一种基于改进CycleGAN(cycle-consistent adversarial networks)的图像数据增强方法。首先,使用较小感受野的卷积核优化CycleGAN网络结构,生... 针对玉米病害图像识别任务存在数据集获取困难、样本不足及不同类别病害样本不均衡等问题,设计一种基于改进CycleGAN(cycle-consistent adversarial networks)的图像数据增强方法。首先,使用较小感受野的卷积核优化CycleGAN网络结构,生成高质量样本图像,减少过拟合现象发生;其次,将SE(squeeze-excitation)注意力机制嵌入到生成器的残差模块中,增强CycleGAN对病害特征的提取能力,使网络更准确地捕捉小目标病害或域间差异不明显的特征。结果显示,改进后的CycleGAN相较于原始CycleGAN、DCGAN、DCGAN+和WGAN算法,生成病害图像的FID分数分别降低了43.33、32.67、24.24和19.72,GAN-train与GANtest相较于原始CycleGAN提升了3.13、4.25百分点;采用改进的CycleGAN图像扩充方法构建玉米病害数据集,基于该数据集的玉米叶片病害识别模型准确率在3种网络架构上均得到有效提升:AlexNet提升3.90百分点,VGGNet提升4.41百分点,ResNet提升3.44百分点,在ResNet网络架构上与传统数据增强算法相比病害识别率提升5.79百分点。结果表明,改进的CycleGAN网络有效解决了玉米病害图像数据集匮乏的问题。 展开更多
关键词 数据增强 玉米叶片病害 残差模块 循环一致性生成对抗网络
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基于改进CycleGAN的非配对CMR图像增强
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作者 郑伟 吴禹波 +2 位作者 冯晓萌 马泽鹏 宋铁锐 《河北大学学报(自然科学版)》 北大核心 2025年第2期204-215,共12页
心脏磁共振成像(cardiac magnetic resonance,CMR)过程中患者误动、异常幅度的呼吸运动、心律失常会造成CMR图像质量下降,为解决现有的CMR图像增强网络需要人为制作配对数据,且图像增强后部分组织纹理细节丢失的问题,提出了基于空频域... 心脏磁共振成像(cardiac magnetic resonance,CMR)过程中患者误动、异常幅度的呼吸运动、心律失常会造成CMR图像质量下降,为解决现有的CMR图像增强网络需要人为制作配对数据,且图像增强后部分组织纹理细节丢失的问题,提出了基于空频域特征学习的循环一致性生成对抗网络(cycle-consistent generative adversavial network based on spatial-frequency domain feature learning,SFFL-CycleGAN).研究结果表明,该网络无须人为制作配对数据集,增强后的CMR图像组织纹理细节丰富,在结构相似度(structural similarity,SSIM)和峰值信噪比(peak signal to noise ratio,PSNR)等方面均优于现有的配对训练网络以及原始的CycleGAN网络,图像增强效果好,有效助力病情诊断. 展开更多
关键词 心脏磁共振成像 图像增强 空频域特征 循环一致性生成对抗网络
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鸭瘟病毒Cycleave荧光PCR检测方法的建立
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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
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改进CycleGAN的半监督建筑物提取算法
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作者 卢鹏 仲闯 《计算机工程》 北大核心 2025年第3期241-251,共11页
建筑物提取需要大量的标注数据进行训练,收集和标注数据需要耗费大量时间。为了在小样本遥感图像数据集上基于半监督学习实现建筑物提取的目的,构建4组建筑物提取数据集,提出了一种基于循环一致性生成对抗网络(CycleGAN)的建筑物提取算... 建筑物提取需要大量的标注数据进行训练,收集和标注数据需要耗费大量时间。为了在小样本遥感图像数据集上基于半监督学习实现建筑物提取的目的,构建4组建筑物提取数据集,提出了一种基于循环一致性生成对抗网络(CycleGAN)的建筑物提取算法。首先,在生成器中引入全局注意力机制(GAM)以增强对建筑物和图像背景细节特征的区分;其次,在判别器中加入谱归一化层以增强训练稳定性,解决了训练过程中梯度消失问题;最后,改进对抗损失和循环一致性损失以提高生成图像的质量,避免生成图像的过度平滑化,并引入Identity损失以限制生成器不会自主修改输入图像的颜色,保证输入图像与输出图像颜色组成的一致性。实验结果表明,在第1组小样本数据集上,与UNIT、MUNIT、U-GAT-IT、SPatchGAN、QS-Attn模型进行半监督实验对比,结构相似性(SSIM)值和准确率分别至少提高了3、8.1百分点,在扩充数据规模的数据集上,使用改进后的算法进行全监督和半监督实验对比,验证了改进后的算法在小样本遥感图像数据集上实现建筑物半监督提取的有效性。 展开更多
关键词 建筑物提取 循环一致性生成对抗网络 谱归一化 全局注意力机制 半监督
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Mechanical and microstructural properties of schist exposed to freezethaw cycles,dry-wet cycles,and alternating actions 被引量:2
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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
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High cycle fatigue performance at 650℃and corresponding fracture behaviors of GH4169 joint produced by linear friction welding 被引量:2
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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
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Hemispheric prediction of solar cycles 25 and 26 from multivariate sunspot time-series data via Informer models 被引量:1
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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
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Carbon emissions in China’s steel industry from a life cycle perspective:Carbon footprint insights 被引量:4
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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
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Recent advances in regulating the cell cycle through inhibiting CDKs for cancer treatment 被引量:1
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作者 Weijiao Chen Xujie Zhuang +6 位作者 Yuanyuan Chen Huanaoyu Yang Linhu Shen Sikai Feng Wenjian Min Kai Yuan Peng Yang 《Chinese Journal of Natural Medicines》 2025年第3期286-298,共13页
The inhibition of cyclin-dependent kinases(CDKs)is considered a promising strategy for cancer treatment due to their role in cell cycle regulation.However,CDK inhibitors with no selectivity among CDK families have not... The inhibition of cyclin-dependent kinases(CDKs)is considered a promising strategy for cancer treatment due to their role in cell cycle regulation.However,CDK inhibitors with no selectivity among CDK families have not been approved.A CDK inhibitor with high selectivity for CDK4/6 exhibited significant treatment effects on breast cancer and has become a heavy bomb on the market.Subsequently,resistance gradually decreased the efficacy of selective CDK4/6 inhibitors in breast cancer treatment.In this review,we first introduce the development of selective CDK4/6 inhibitors and then explain the role of CDK2 activation in inducing resistance to CDK4/6 inhibitors.Moreover,we focused on the development of CDK2/4/6 inhibitors and selective CDK2 inhibitors,which will aid in the discovery of novel CDK inhibitors targeting the cell cycle in the future. 展开更多
关键词 Cell cycle cyclin-dependent kinase(CDK) CDK inhibitor RESISTANCE
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Effects of high temperature and thermal cycles on fracture surface's roughness of granite:An insight on 3D morphology 被引量:1
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作者 Qixiong Gu Zhen Huang +5 位作者 Kui Zhao Wen Zhong Li Liu Xiaozhao Li Yun Wu Ma Dan 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第2期810-826,共17页
The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle o... The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles. 展开更多
关键词 GRANITE Thermal cycles High temperature Fracture surface roughness ANISOTROPIC Thermal damage
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Impacts of the annual cycle of background SST in the tropical Pacific on the phase and amplitude of ENSO
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作者 Song Jiang Congwen Zhu Ning Jiang 《Atmospheric and Oceanic Science Letters》 2025年第1期12-17,共6页
The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO).... The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO).However,there is no consensus yet on its anomalous impacts on the phase and amplitude of ENSO.Based on data during 1982-2022,results show that anomalies of the antisymmetric mode can affect the evolution of ENSO on the interannual scale via Bjerknes feedback,in which the positive(negative)phase of the antisymmetric mode can strengthen El Niño(La Niña)in boreal winter via an earlier(delayed)seasonal cycle transition and larger(smaller)annual mean.The magnitude of the SST anomalies in the equatorial eastern Pacific can reach more than±0.3◦C,regulated by the changes in the antisymmetric mode based on random sensitivity analysis.Results reveal the spatial pattern of the annual cycle associated with the seasonal phase-locking of ENSO evolution and provide new insight into the impact of the annual cycle of background SST on ENSO,which possibly carries important implications for forecasting ENSO. 展开更多
关键词 Annual cycle SST anomaly Antisymmetric mode ENSO
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Microstructure deterioration of sandstone under freeze-thaw cycles using CT technology:The effects of different water immersion conditions 被引量:1
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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
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Performance of stabilized copper mine tailings with freeze-thaw and wet-dry seasonal cycles 被引量:1
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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
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Proposal of Integrations to the Italian Road Regulation on Cycle Mobility:Learning from Foreign Best Practices
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作者 Michèle Pezzagno 《Journal of Civil Engineering and Architecture》 2025年第2期92-103,共12页
Under many aspects Italy would be ideal for cycling:the weather is favourable for a good part of the year and many historic centres are characterized by roads which would mainly be suitable for bicycle traffic.The pos... Under many aspects Italy would be ideal for cycling:the weather is favourable for a good part of the year and many historic centres are characterized by roads which would mainly be suitable for bicycle traffic.The positive aspects relating to cycling are well known,but unfortunately,the use of bicycles in Italy is still poor and the main cause of this phenomenon is certainly relating to a general lack of safety in cycling.In the last decade,in Italy the trend of road accidents and victims is generally decreasing,but,at the same time,the number of cyclists involved in road accidents increased by 24,5%,therefore,more attention to cyclists as Vulnerable Road Users is absolutely needed.The causes of this high accident rate is mainly relating to a lack of national legislation or to standards which are old,often overlapped to regional guidelines,uneven,confusing and in some case also contradictory.In terms of cycle network planning,it should be reminded that in Italy there is no regulation that establishes the criteria for a functional classification of bicycle paths.As a consequence,the infrastructure geometry and facilities(bicycle parking,places of refreshments,cycle repair shops,etc.)are not properly put in relation to the role played by the cycle path in the territory.In the course of time,we assisted to the realization of isolated cycle path trunks,generally out of a planning strategy and characterized by their own geometry.Therefore,taking also inspiration by the standards developed in other European Countries,this research tries to provide guidelines for pre-normative functional classification of cycle paths,for their design and planning,in order to obtain safe and homogeneous cycling routes in Italy.It should be noted that the technical solutions,devices and traffic regulations,adopted in other countries,are very effective for a safe cycle mobility,but need to be revised in relation to the existing Italian law. 展开更多
关键词 cycling safety cycle path planning vulnerable road users infrastructure geometry
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On the Occurrence of Different Classes of Solar Flares during the Solar Cycles 23 and 24
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作者 Longo Wilfried Sanon Wendpuiré Ousmane Compaoré +1 位作者 Somaïla Koala Jean Louis Zerbo 《Journal of High Energy Physics, Gravitation and Cosmology》 2025年第1期28-38,共11页
In this study we review the occurrence of different types (A, B, C, M, and X classes) of solar flares during different solar cycle phases from 1996 to 2019 covering the solar cycles 23 and 24. During this period, a to... In this study we review the occurrence of different types (A, B, C, M, and X classes) of solar flares during different solar cycle phases from 1996 to 2019 covering the solar cycles 23 and 24. During this period, a total of 19,126 solar flares were observed regardless the class: 3548 flares in solar cycle 23 (SC23) and 15,668 flares in solar cycle 24 (SC24). Our findings show that the cycle 23 has observed the highest occurrences of M-class and X-class flares, whereas cycle 24 has pointed out a predominance of B-class and C-class flares throughout its different phases. The results indicate that the cycle 23 was magnetically more intense than cycle 24, leading to more powerful solar flares and more frequent geomagnetic storms, capable of generating significant electromagnetic emissions that can affect satellites and GPS signals. The decrease in intense solar flares during cycle 24 compared to cycle 23 reflects an evolution in solar activity patterns over time. 展开更多
关键词 Solar Flare Solar cycle Solar cycle Phase Solar Flare Class OCCURRENCE
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Solar cycles during the seventeenth century revealed by equatorial aurora records
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作者 Yong Wei LiMei Yan 《Earth and Planetary Physics》 EI CAS 2025年第1期182-187,共6页
Solar cycles are fundamental to astrophysics,space exploration,technological infrastructure,and Earth's climate.A better understanding of these cycles and their history can aid in risk mitigation on Earth,while al... Solar cycles are fundamental to astrophysics,space exploration,technological infrastructure,and Earth's climate.A better understanding of these cycles and their history can aid in risk mitigation on Earth,while also deepening our knowledge of stellar physics and solar system dynamics.Determining the solar cycles between 1600 and 1700-especially the post-1645 Maunder Minimum,characterized by significantly reduced solar activity-poses challenges to existing solar activity proxies.This study utilizes a new red equatorial auroral catalog from ancient Korean texts to establish solar cycle patterns from 1623 to 1700.Remarkably,a further reevaluation of the solar cycles between 1610 and 1755 identified a total of 13 cycles,diverging from the widely accepted record of 12 cycles during that time.This research enhances our understanding of historical solar activity,and underscores the importance of integrating diverse historical sources into modern analyses. 展开更多
关键词 solar cycle Maunder Minimum solar activity red equatorial aurora West Pacific geomagnetic anomaly
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基于CycleGAN的土壤CT/SEM图像多尺度融合方法
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作者 黄梓菡 韩巧玲 +2 位作者 赵玥 赵燕东 宋美慧 《林业科学》 北大核心 2025年第8期116-128,共13页
【目的】针对土壤CT图像超分辨率重建任务依赖成对数据集的问题,提出一种基于循环生成对抗网络(CycleGAN)的土壤CT/SEM图像多尺度融合方法(MSF-CycleGAN),提升土壤CT图像质量,降低高分辨率采集CT图像成本,为农林业的智能化管理提供新的... 【目的】针对土壤CT图像超分辨率重建任务依赖成对数据集的问题,提出一种基于循环生成对抗网络(CycleGAN)的土壤CT/SEM图像多尺度融合方法(MSF-CycleGAN),提升土壤CT图像质量,降低高分辨率采集CT图像成本,为农林业的智能化管理提供新的技术支持。【方法】首先,构建土壤CT图像和土壤SEM图像数据集,共包含3种含水率下多次冻融循环的土柱样本,为后续图像分辨率提升提供数据基础。其次,引入适用于跨域转换的CycleGAN网络模型应用于土壤CT/SEM图像多尺度融合任务,利用CT与SEM图像的不同成像特性补充低分辨率土壤CT图像信息。为提高生成图像的分辨率,在生成器A中加入上采样模块,在生成器B中加入下采样模块。为增强图像的真实性和一致性,采用双线性插值法将原始图像上采样后加入身份损失函数的计算。最后,基于改进ConvNeXt网络模型对融合高分辨率图像进行孔隙分割,构建三维孔隙模型并进行参数提取。【结果】在相同试验条件下,本研究从定性、定量角度对比MSF-CycleGAN与超分辨率重建算法,证明MSF-CycleGAN多尺度融合方法能够提高土壤CT图像的分辨率且效果比超分辨率重建算法更明显。引入SEM图像和身份损失函数,验证了二者设计的有效性。对50%、75%、100%含水率土柱的图像多尺度融合试验表明,融合后的土壤三维模型能够观察到更多细小孔隙,孔隙数量增加2倍,孔隙率较融合前提高3.93%,孔隙成圆率提高3.64%,分形维数提高0.55%。孔隙参数量化试验表明,基于高分辨率融合图像分割量化的孔隙参数在冻融循环下的变化更符合现有研究规律,证明本研究方法能够准确、有效提高土壤CT图像的分辨率。【结论】本研究论证将土壤CT图像与SEM图像进行多尺度融合提高CT图像分辨率的可行性,为降低采集高分辨率图像成本提供了新的技术路线,能够推动土壤结构研究的精细化与智能化发展。 展开更多
关键词 土壤 多尺度融合 循环生成对抗网络 CT图像 SEM图像
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