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Application of Motic Digital Microscope Mutual System in the Experimental Teaching of Medicinal Plants
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作者 Hailin LU Min GUO +3 位作者 Shenggao YIN Bin LI Yonghua LI Haicheng WEN 《Medicinal Plant》 2025年第2期88-90,共3页
In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly effi... In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy. 展开更多
关键词 microscope Medicinal plants Mutual system Experimental teaching
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An investigation of single-phased metallic solidification process using high-temperature confocal laser scanning microscope combined with differential scanning colorimetry
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作者 Xing-zhi Zhou De-yong Wang +6 位作者 Tian-peng Qu Dong Hou Shao-yan Hu Jun Tian Xiang-long Li Lei Fan Zhi-xiao Zhang 《Journal of Iron and Steel Research International》 2025年第2期437-451,共15页
To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1... To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates. 展开更多
关键词 NUCLEATION Metallic solidification process Differential scanning colorimetry High-temperature confocal laser scanning microscope Interfacial wetting-lattice mismatch heterogeneous nucleation model
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VMD与时间-空间分数阶扩散模型联合分段TEM滤波 被引量:1
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作者 谭超 谭继伟 +4 位作者 沈艳军 袁永榜 欧星作 闵薪宇 孙其浩 《重庆邮电大学学报(自然科学版)》 北大核心 2025年第2期204-214,共11页
为滤除瞬变电磁(transient electromagnetic method,TEM)信号中的噪声,提出一种变分模态分解(variational mode decomposition,VMD)与时间-空间分数阶非线性扩散模型(time-space fractional-order diffusion model,TSFDM)的分段滤波方... 为滤除瞬变电磁(transient electromagnetic method,TEM)信号中的噪声,提出一种变分模态分解(variational mode decomposition,VMD)与时间-空间分数阶非线性扩散模型(time-space fractional-order diffusion model,TSFDM)的分段滤波方法。针对TEM信号的特点,将采样信号进行动态阈值分段处理;采用VMD对每一段信号自适应分解,保留第一个内涵模态(intrinsic mode function,IMF)分量作为初次滤波数据;分别使用差分离散和使用带位移的Grunwald-Letnikov逼近法来近似求解时间-空间分数阶扩散方程的时间Caputo分数阶导数和空间Riemann-Liouville分数阶导数,建立迭代收敛差分方程,设置平滑算子得到TSFDM滤波器;利用叠加平均法对TSFDM迭代计算得到的二次滤波信号进行拼接得到完整TEM信号。仿真结果表明,使用所提方法后,整体信号质量提高约22 dB,后期信号信噪比提高约38 dB,与原始信号接近;与传统方法相比,所提方法各项评价指标更优;实测TEM信号中衰减特征被保留,有效还原了频域曲线变化趋势。 展开更多
关键词 瞬变电磁信号(tem)滤波 变分模态分解 阈值分段 时间-空间分数阶扩散模型(TSFDM) 差分方程
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基于TEM8写作新题型实证分析的英语专业教学改革思辨
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作者 张丽娟 许慧洁 《浙江工业大学学报(社会科学版)》 2025年第2期224-229,235,共7页
教育部高等学校外语专业教学委员会直接指导下的规模化标准考试TEM8是国内检验英语专业水平的最高等级测试,是检验英语专业办学质量的重要指标之一,在“新文科”建设背景下更是进行教学建设和教学改革的重要参考依据。基于现场阅卷和教... 教育部高等学校外语专业教学委员会直接指导下的规模化标准考试TEM8是国内检验英语专业水平的最高等级测试,是检验英语专业办学质量的重要指标之一,在“新文科”建设背景下更是进行教学建设和教学改革的重要参考依据。基于现场阅卷和教学实践经验,聚焦2019年TEM8写作,探讨新题型中应该引起教学高度关注的测试点,解读其中试题设计、评分标准和评分结果的内在逻辑关联,以期为英语专业教学改革提供有益参考。为加强TEM8考试正向反拨作用,应该推动以培养思辨能力为宗旨的课程体系改革、以人文通识教育为目标的课程内容改革和以自主学习机制为支撑的教学模式改革。 展开更多
关键词 tem8写作 英语专业 思辨能力 人文通识教育 自主学习
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原位TEM双离子束辐照钨的位错环演化研究
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作者 马鹏飞 刘艳 +5 位作者 曹留烜 张亚培 李修锐 田文喜 秋穗正 苏光辉 《原子能科学技术》 北大核心 2025年第4期874-883,共10页
钨由于在高温下具有优良的抗辐照性能而被认为可应用于聚变堆中面向等离子体材料(PFM,plasma-facing material)。聚变堆中产生大量热负荷和中子以及氢氦气体原子使钨的应用面临苛刻的环境考验。为了进一步探究钨应用于PFM时辐照损伤剂... 钨由于在高温下具有优良的抗辐照性能而被认为可应用于聚变堆中面向等离子体材料(PFM,plasma-facing material)。聚变堆中产生大量热负荷和中子以及氢氦气体原子使钨的应用面临苛刻的环境考验。为了进一步探究钨应用于PFM时辐照损伤剂量对其辐照性能的影响机制,本文采用Kr^(+)&He^(+)双离子束以不同的辐照损伤剂量对钨进行辐照。通过原位TEM观察辐照损伤剂量对<100>和1/2<111>位错环的演化现象影响,并对其演化进行量化分析。结果表明,辐照损伤剂量的增加导致1/2<111>位错环生成与长大以及<100>位错环消失。Kr^(+)&He^(+)双离子束辐照下,<100>位错环的增殖与湮灭对钨的机械性能产生重大影响。本文深化了对钨的辐照损伤研究,为钨在聚变堆中的应用提供基础。 展开更多
关键词 面向等离子体材料 双离子束辐照 原位tem 位错环
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窗口气室原位TEM在负载型金属催化剂研究中的应用进展
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作者 刘傲天 姜健准 +3 位作者 满毅 李劭轩 柳颖 白羽 《石油化工》 北大核心 2025年第9期1355-1362,共8页
窗口气室原位TEM能够模拟催化剂真实工作压力环境,近年来受到越来越多的关注。综述了两种典型原位可控环境TEM的特点,介绍了窗口气室原位TEM在负载型单金属催化剂、负载型双/多金属催化剂和负载型单原子金属催化剂领域的应用进展,展望... 窗口气室原位TEM能够模拟催化剂真实工作压力环境,近年来受到越来越多的关注。综述了两种典型原位可控环境TEM的特点,介绍了窗口气室原位TEM在负载型单金属催化剂、负载型双/多金属催化剂和负载型单原子金属催化剂领域的应用进展,展望了该技术未来的发展潜力。 展开更多
关键词 原位tem 环境tem 窗口气室 负载型金属催化剂 催化剂表征 微观结构
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电性源TEM磁场两分量正演方法研究
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作者 李奇霖 张永超 +2 位作者 王光杰 李志远 王若 《地球物理学进展》 北大核心 2025年第4期1601-1609,共9页
为进一步探讨多分量探测是否有利于增大探测深度,本文首先从TEM三分量方法出发,详细推导了晚期三分量响应的近似表达式;其次,结合近似表达式自变量影响因素,对不同收发距下y、z两分量在深部探测的衰减特征进行研究;最后以油气藏地质条... 为进一步探讨多分量探测是否有利于增大探测深度,本文首先从TEM三分量方法出发,详细推导了晚期三分量响应的近似表达式;其次,结合近似表达式自变量影响因素,对不同收发距下y、z两分量在深部探测的衰减特征进行研究;最后以油气藏地质条件为参考,对磁场两分量探测深度进行了定性分析.研究结果表明:y分量是有效的TEM方法接收分量,且信号强度与收发距存在密切关系,适当收发距下y分量可以弥补z分量晚期衰减快的缺陷,两分量接收可以提高TEM探测的信噪比和减少反演的多解性. 展开更多
关键词 瞬变电磁 磁场y分量 探测深度 正演
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In-situ observation and analysis of high temperature behavior of carbides in GCr15 bearing steel by confocal laser scanning microscopy 被引量:2
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作者 Jun Ren Yue Teng +4 位作者 Xiang Liu Xi Xu Hui-gai Li Ke Han Qi-jie Zhai 《Journal of Iron and Steel Research International》 2025年第2期409-417,共9页
The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution ki... The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution kinetics of primary carbides during either heating or soaking.Dissolution of carbides proceeded in three stages(fast→slow→faster)as either temperature or holding time was increased.During the heating process and during the first and third stages of the soaking process,the original size of the carbides determined the steepness of the slope,but during the middle(“slow”)stage of the soaking process,the slope remained zero.The initial size of the carbides varied greatly,but their final dissolution temperature fell within the narrow range of 1210-1235℃,and the holding time remained within 50 min.Fractal analysis was used to study the morphological characteristics of small and medium-sized carbides during the dissolution process.According to changes in the fractal dimension before and after soaking,the carbides tended to evolve towards a more regular morphology. 展开更多
关键词 Bearing steel High-temperature confocal laser scanning microscope In-situ observation Primary carbide Fractal analysis
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FIB-TEM解析微生物铀矿化:以松辽盆地海力锦砂岩型铀矿为例
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作者 金伟国 尹烁 +1 位作者 王庆飞 潘家永 《现代地质》 北大核心 2025年第2期248-262,共15页
针对砂岩型铀矿中微生物与矿物互作机制证据链薄弱的关键科学问题,本研究以松辽盆地海力锦矿床姚家组下段含铀独居石为研究对象,通过微区矿物学分析揭示其溶蚀过程与铀活化机理。基于钻孔岩心系统取样,采用FIB-TEM联用技术首次在独居石... 针对砂岩型铀矿中微生物与矿物互作机制证据链薄弱的关键科学问题,本研究以松辽盆地海力锦矿床姚家组下段含铀独居石为研究对象,通过微区矿物学分析揭示其溶蚀过程与铀活化机理。基于钻孔岩心系统取样,采用FIB-TEM联用技术首次在独居石溶蚀界面识别出氢铀云母与沥青铀矿纳米矿物组合,结合电子探针原位分析发现溶蚀相独居石平均损失75%初始铀。研究揭示:(1)石英包裹效应导致独居石选择性溶蚀特征,开放体系下溶蚀强度提升3~4个数量级;(2)溶蚀界面纳米矿物相的定向分布指示微生物代谢产生的有机酸主导磷铀耦合释放过程;(3)建立的生物膜催化动力学模型显示,微生物介导的界面反应使铀活化至沉淀。该研究不仅为微生物与纳米矿物间协同成矿机制提供了关键的显微尺度证据,而且对于促进铀矿地质学研究向更精细的微观领域深入拓展具有重要的意义。 展开更多
关键词 海力锦铀矿床 独居石溶解动力学 微生物铀矿化 FIB-tem联用技术 纳米矿物
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基于改进DeepLabV3+的水稻白叶枯病原菌TEM图像分割
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作者 王静 范馨月 《激光杂志》 北大核心 2025年第6期89-95,共7页
针对多个水稻白叶枯病原菌挤压、重叠及杂质干扰等因素,导致细胞边界清晰度下降、轮廓分割不准确等问题,提出改进DeepLabV3+图像分割方法。首先,为排除外部因素干扰,根据细胞分裂不同状态进行分类,使用YOLOv4目标检测模型提取每个类别... 针对多个水稻白叶枯病原菌挤压、重叠及杂质干扰等因素,导致细胞边界清晰度下降、轮廓分割不准确等问题,提出改进DeepLabV3+图像分割方法。首先,为排除外部因素干扰,根据细胞分裂不同状态进行分类,使用YOLOv4目标检测模型提取每个类别病原菌图像;其次,为防止在单一尺度特征提取的目标方式使图像上大目标特征提取冗余以及小目标发生丢失,导致输出特征层清晰度降低的问题,通过多尺度特征融合网络结构提高特征学习的表征能力和精度;进而,引入通道注意力机制,突出对重要影响通道信息特征的学习能力,抑制冗余信息;最后,与经典分割模型DeepLabV3+、Unet、PSPNet和YOLOv10对比,根据mIOU、Precision、Accuracy、Recall以及mPA评价指标结果分析,表明改进DeepLabV3+模型在水稻白叶枯病原菌TEM图像分割精度与效果上均有一定提升。 展开更多
关键词 DeepLabV3+ 多尺度融合 通道注意力 图像分割 tem图像
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Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope
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作者 Qiang Liu Xiang Li +3 位作者 Shen Du Ming Gao Yanbin Yin Jiongming Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期102-110,共9页
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest... During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels. 展开更多
关键词 mold flux low basicity BUBBLES three-dimensional X-ray microscope VISCOSITY
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复杂条件下深埋条带采空区TEM探测技术
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作者 马炳镇 《煤炭技术》 CAS 2025年第1期125-130,共6页
城市郊区的电磁环境较为复杂,为实现复杂条件下深埋煤矿条带采空区有效探查,采用施工装置灵活、对低阻积水采空区响应敏感的TEM(瞬变电磁法)进行探测。先对勘探区地表探测条件的复杂性进行了分析介绍,然后讨论了条带采空区覆岩三带发育... 城市郊区的电磁环境较为复杂,为实现复杂条件下深埋煤矿条带采空区有效探查,采用施工装置灵活、对低阻积水采空区响应敏感的TEM(瞬变电磁法)进行探测。先对勘探区地表探测条件的复杂性进行了分析介绍,然后讨论了条带采空区覆岩三带发育规律与围岩介质电性特征,分析其探测目标体与围岩介质存在较明显的电阻率差异,使其具备了较好的地球物理勘探前提条件。项目实施过程中,首先做好设计及施工阶段有效针对性的技术保障措施,保证获取的一手数据资料质量可靠;其次,在资料处理阶段,采用电磁噪声干扰校正技术和约束反演技术,提高对地质异常体的探测分辨能力,实现对目标体的有效探测。经钻探验证探测成果可靠,为后期注浆治理工作提供了有力支撑。 展开更多
关键词 tem探测 条带采空区 电磁干扰校正 约束反演
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高校英语阅读教学与TEM4阅读理解的有机融合
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作者 王禹莹 孙慧敏 《英语广场(学术研究)》 2025年第5期133-136,共4页
TEM4作为国内考查英语专业学生语言综合运用能力的关键性测试,其中阅读理解部分占有较大比重且一直是学生需要攻克的难点之一。本文以近三年TEM4阅读部分为切入点,探讨江苏省某独立学院将英语阅读教学与TEM4有机融合的教学实践及其效果... TEM4作为国内考查英语专业学生语言综合运用能力的关键性测试,其中阅读理解部分占有较大比重且一直是学生需要攻克的难点之一。本文以近三年TEM4阅读部分为切入点,探讨江苏省某独立学院将英语阅读教学与TEM4有机融合的教学实践及其效果。研究发现,通过将TEM4阅读理解融入英语阅读课堂内外,优化教学设计和方法,教师可以为学生提供更为系统且有针对性的学习指导,提高学生综合阅读能力和思维能力,培养其良好的阅读习惯,从而辅助其提升阅读部分的得分率,进一步提高考试通过率。 展开更多
关键词 tem4 英语阅读 阅读教学
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Impact of message fatigue and individual behavioral responses on epidemiological spread in temporal simplicial networks 被引量:1
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作者 Xiao-Nan Fan Xuemei You 《Chinese Physics B》 2025年第3期32-43,共12页
Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refer... Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refers to the psychological response characterized by feelings of boredom and anxiety that occur after receiving an excessive amount of similar information.This phenomenon can alter individual behaviors related to epidemic prevention.Additionally,recent studies indicate that pairwise interactions alone are insufficient to describe complex social transmission processes,and higher-order structures representing group interactions are crucial.To address this,we develop a novel epidemic model that investigates the interactions between information,behavioral responses,and epidemics.Our model incorporates the impact of message fatigue on the entire transmission system.The information layer is modeled using a static simplicial network to capture group interactions,while the disease layer uses a time-varying network based on activity-driven model with attractiveness to represent the self-protection behaviors of susceptible individuals and self-isolation behaviors of infected individuals.We theoretically describe the co-evolution equations using the microscopic Markov chain approach(MMCA)and get the epidemic threshold.Experimental results show that while the negative impact of message fatigue on epidemic transmission is limited,it significantly weakens the group interactions depicted by higher-order structures.Individual behavioral responses strongly inhibit the epidemic.Our simulations using the Monte Carlo(MC)method demonstrate that greater intensity in these responses leads to clustering of susceptible individuals in the disease layer.Finally,we apply the proposed model to real networks to verify its reliability.In summary,our research results enhance the understanding of the information-epidemic coupling dynamics,and we expect to provide valuable guidance for managing future emerging epidemics. 展开更多
关键词 Monte Carlo simulation microscopic Markov chain approach message fatigue information-epidemic coupled spreading simplicial complex
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小线框源TEM拟MT二维反演技术及超前地质预报应用
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作者 韩自强 万玛龙智 +4 位作者 李祥丰 杨永强 朱小明 雒成贤 唐立 《煤田地质与勘探》 北大核心 2025年第8期203-215,共13页
【目的】针对瞬变电磁法(transient electromagnetic method,TEM)超前地质预报多维反演计算效率低,难以实用化的瓶颈,提出一种基于时频转换的小线框源TEM拟大地电磁法(magnetotelluric,MT)二维反演技术。【方法】首先证明小线框源TEM晚... 【目的】针对瞬变电磁法(transient electromagnetic method,TEM)超前地质预报多维反演计算效率低,难以实用化的瓶颈,提出一种基于时频转换的小线框源TEM拟大地电磁法(magnetotelluric,MT)二维反演技术。【方法】首先证明小线框源TEM晚期视电阻率与MT卡尼亚视电阻率在超前地质预报常用参数下具有显著相似性;引入最佳时频转换系数(C_(TF))实现晚期视电阻率向卡尼亚视电阻率的快速转换,转换偏差最大平均值为3.7%,转换偏差整体较小;进而利用MT成熟的反演方法处理转换数据。【结果】(1)拟MT一维反演结果中,电阻率相对误差最大为6.14%,深度相对误差最大为5.73%,反演误差整体较小。(2)拟MT二维反演结果中,含水构造上方测线的反演结果能够确定含水构造的边界位置和真实深度,反演电阻率更接近含水构造的真实电阻率值;含水构造以外测线的反演结果能够反映出低阻含水构造的存在,但各具体反演参数与实际存在一定偏差。【结论】该方法在普通PC端计算耗时<20 min,提升了计算效率和预报精度,为TEM超前地质预报提供实用化二维反演新途径。 展开更多
关键词 瞬变电磁法(tem) 小线框源 大地电磁法(MT) 超前地质预报 二维反演 时频转换 卡尼亚视电阻率
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透射电镜中STEM成像技术的原理、分类及应用
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作者 张放 梁超伦 郭琳娜 《分析仪器》 2025年第5期95-103,共9页
近年来,透射电子显微技术取得了突飞猛进的发展,扫描透射技术(STEM)尤为瞩目。作为一种能够在原子尺度上实现材料微结构与精细化学组分表征分析的先进手段,STEM为从微观尺度理解材料宏观性能提供了关键依据。本文系统介绍并对比了透射... 近年来,透射电子显微技术取得了突飞猛进的发展,扫描透射技术(STEM)尤为瞩目。作为一种能够在原子尺度上实现材料微结构与精细化学组分表征分析的先进手段,STEM为从微观尺度理解材料宏观性能提供了关键依据。本文系统介绍并对比了透射电镜中几种典型的扫描透射成像技术,包括环形明场像(ABF)、环形暗场像(ADF)、积分差分相位衬度像(iDPC)及4D-STEM技术,深入解析其成像原理、技术特点及科学研究中的代表性应用案例,旨在帮助科研工作者更全面地理解STEM成像技术体系,并为其在各自学术与科研领域的应用提供参考。 展开更多
关键词 透射电镜 ABF-Stem ADF-Stem iDPC-Stem 4D-Stem
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Hybrid CO_(2) thermal system for post-steam heavy oil recovery:Insights from microscopic visualization experiments and molecular dynamics simulations
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作者 Ning Lu Xiaohu Dong +4 位作者 Haitao Wang Huiqing Liu Zhangxin Chen Yu Li Deshang Zeng 《Energy Geoscience》 2025年第2期233-248,共16页
The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments... The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments and molecular dynamics(MD)simulations,this study investigates the microscopic enhanced oil recovery(EOR)mechanisms underlying residual oil removal using hybrid CO_(2) thermal systems.Based on the experimental models for the occurrence of heavy oil,this study evaluates the performance of hybrid CO_(2) thermal systems under various conditions using MD simulations.The results demonstrate that introducing CO_(2) molecules into heavy oil can effectively penetrate and decompose dense aggregates that are originally formed on hydrophobic surfaces.A stable miscible hybrid CO_(2) thermal system,with a high effective distribution ratio of CO_(2),proficiently reduces the interaction energies between heavy oil and rock surfaces,as well as within heavy oil.A visualization analysis of the interactions reveals that strong van der Waals(vdW)attractions occur between CO_(2) and heavy oil molecules,effectively promoting the decomposition and swelling of heavy oil.This unlocks the residual oil on the hydrophobic surfaces.Considering the impacts of temperature and CO_(2) concentration,an optimal gas-to-steam injection ratio(here,the CO_(2):steam ratio)ranging between 1:6 and 1:9 is recommended.This study examines the microscopic mechanisms underlying the hybrid CO_(2) thermal technique at a molecular scale,providing a significant theoretical guide for its expanded application in EOR. 展开更多
关键词 Heavy oil Hybrid CO_(2)thermal system Microscopic visualization experiment Molecular dynamics simulation Microscopic mechanism
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Revealing high-temperature oxidation behavior and structure evolution of SnS:an electron microscopic investigation
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作者 Si-Kang Zheng Zhen-Hua Zhang +8 位作者 Yan-Yan Tao Xiao-Meng Yang Jie Liu Hong-Hui Wang Guang Han Xu Lu Guo-Yu Wang Bin Zhang Xiao-Yuan Zhou 《Rare Metals》 2025年第6期4086-4094,共9页
SnS,a well-known van der Waals chalcogenide,is susceptible to oxidation in high-temperature or highhumidity environments,significantly impacting its functional performance and device stability.Conversely,oxidation can... SnS,a well-known van der Waals chalcogenide,is susceptible to oxidation in high-temperature or highhumidity environments,significantly impacting its functional performance and device stability.Conversely,oxidation can be used as an effective strategy for surface engineering,allowing for structure modulation or design,property tuning and application exploration.However,there is currently a gap in understanding the relationship between the oxidation behavior of SnS,the structure of its oxidized surface,and the dependence on oxidation temperature.In this study,we systematically investigated the evolution of SnS surfaces under thermal oxidation using electron microscopy.The microstructure evolution(e.g.,surface structures,phases,defects,and interface)of SnS during high-temperature oxidation has been fully characterized and studied based on cross-sectional samples.Various surface heterostructures were constructed,including SnO_(2)/SnS,SnO_(2)/SnS_(2)/SnS,and SnO_(2)/Sn_(2)S_(3)/SnS,offering significant potential for the surface functionalization of SnS-based systems.Accordingly,oxidation mechanisms at different stages were elucidated based on the detailed and clear picture of microstructures.This research not only deepens our understanding of the fundamental science of SnS oxidation but also provides valuable insights for preventing and developing surface oxidation engineering in SnS and other van der Waals chalcogenides/materials. 展开更多
关键词 SNS Oxidation Heterogeneous surfaces Electron microscopic investigation Formation mechanism
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Macro-and micro-mechanical response and damage mechanism of sandstone under high-temperature conditions
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作者 Laiwei Wu Yanli Huang +5 位作者 Junmeng Li Guiyuan Wang Yingshun Li Xiaotong Li Junzhi Chen Chuning Ji 《International Journal of Mining Science and Technology》 2025年第2期265-274,共10页
The thermal effects of coal combustion considerably influence the physical and chemical properties,structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. I... The thermal effects of coal combustion considerably influence the physical and chemical properties,structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. In this study, the impacts of temperature on the physical and chemical characteristics(i.e., mineral phase, microstructure, and mechanical strength) of sandstone were investigated by employing experimental methods, including microstructural analysis, uniaxial acoustic emission(AE), and nuclear magnetic resonance(NMR). The results indicate that temperature alters the mineral phase and the pore characteristics, and these two factors jointly affect the mechanical properties of sandstone. The influence of temperature on the mechanical strength of sandstone is categorized into low-temperature strengthening and high-temperature damage, with a threshold temperature identified at 600 ℃. The lowtemperature strengthening effect encompasses both pore strengthening and mineral phase strengthening, while the high-temperature damage effect primarily results from pore damage. As the experimental temperature rises, both the number of AE events and the AE energy transition from a surge in the postpeak failure stage to a stepwise increase during the loading process. This transition implies that the failure mode of the sandstone sample evolves from brittle failure to tensile failure. 展开更多
关键词 Thermal effects Mineral phase Pore structure Acoustic emission energy Microscopic morphology
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Macro and micro mechanical behaviors and micro damage theory of rock at low temperature freeze-thaw cycles
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作者 XIAO Peng CHEN Youliang +1 位作者 FERNÁNDEZ-STEEGER Tomás Manuel RAFIG Azzam 《Journal of Mountain Science》 2025年第6期2227-2240,共14页
Aiming at challenges posed by rock freezethaw(FT)in cold regions rock mass engineering,it is of great significance to analyze its macro-and micromechanical properties and damage laws for the smooth progress of constru... Aiming at challenges posed by rock freezethaw(FT)in cold regions rock mass engineering,it is of great significance to analyze its macro-and micromechanical properties and damage laws for the smooth progress of construction.In this study,indoor freezethaw cycle(FTC)tests on sandstone were conducted to analyze the mass change rate,density change rate,longitudinal wave velocity change rate,microstructure change and mechanical properties of sandstone after FTC.A microscopic FT damage variable reflecting the FT damage was defined based on the changes of rock porosity before and after the FTC,enabling the derivation of the total damage variable under the coupled action of FTC and mechanical loading.A damage evolution equation and a microscopic damage constitutive model for rock under coupled FTC and confining pressure were established by using Lemaitre’s strain equivalence principle,the theory of continuous damage mechanics,and the assumption that the failure of rock micro-units follows the SMP criterion.The rationality and accuracy of the model were verified using triaxial compression test data for FT-damaged rock.The results show that both macroand micro-mechanical properties of sandstone are degraded under the action of FTC,resulting in significant damage.The developed microscopic damage constitutive model can reflect the stress-strain characteristics of the whole process of FT rock triaxial compression,with excellent agreement observed between experimental and theoretical curves.This validates the reliability of the model and the methodology for determining its parameters.Additionally,defining the microscopic FT damage variable based on rock porosity changes is demonstrated to be a feasible and highly accurate approach to reflect rock FT damage degree.This model expands the damage model for rock under the coupling effect of FTC and confining pressure,further illuminating the damage mechanism and failure law in such environments.The findings provide references for the construction of rock mass engineering in cold regions. 展开更多
关键词 Freeze-thaw cycles Mechanical properties Microscopic freeze-thaw damage variable Damage evolution Constitutive model
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