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Formation estimation and evolution mechanism of the pressure arch for non-circular tunnels under asymmetrical stress field

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Science China(Technological Sciences) 2024年第9期67卷 2919-2938页

作者： sun zhenyu ZHANG DingLi XU Tong CHEN Xu Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

The tunneling-induced stress redistribution is dependent on the tunnel shape and the in-situ stress field, and the previous arch characterization method based on the circumferential or maximum principal stresses is only suitable for the circular tunnels under the hydrostatic stress field. In this study, a unified characterization method of the pressure arch for non-circular tunnels under the arbitrary stress field is proposed. By comparing the variations of compressive stress in different directions due to excavation, the ratio of the most significant increase in compressive stress is presented to characterize the arch effect, and the corresponding numerical algorithm is given. Since the proposed method takes the stress element as the basic analytical model, it can be easily applied to various complex excavation situations. Thereafter, combined with the established folding catastrophic model, an objective and unified quantitative method of the pressure arch boundaries is given. Using the proposed method, the longitudinal evolution of the pressure arch is analyzed. According to the expansion rate of the arch boundaries, three evolution stages including the initial formation, rapid expansion and stabilization are categorized. Parametric studies are conducted to illustrate the effect of ground properties and support stiffness on the pressure arch formation. It is found that the ground strength parameters and burial depth affect the arch range at a decreasing rate, while they have little effect on the arch shape. The lateral pressure coefficient has a significant effect on both the shape and range of the pressure arch. Increasing the support stiffness helps reduce the pressure arch range with a decreasing rate, while the synchronous variation of the elastic moduli of the surrounding rock and support does not affect the arch range under a certain relative elastic modulus. Finally, field monitoring is conducted to validate the proposed method in actual support design.

关键词： pressure arch stress redistribution numerical simulation quantitative characterization longitudinal evolution parametric study

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Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1936-1951页

作者： zhenyu sun Dingli Zhang Qian Fang Yanjuan Hou Nanqi Huangfu Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing100044China

To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface *** rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown *** to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the *** case is divided into three stages due to the different effects of the active rockbolts and the passive surface *** fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be *** using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are *** proposed analytical solutions are validated by a series of 3D numerical *** parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock *** results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable *** tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain *** proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support

关键词： Analytical model Longitudinal tunnel displacement Fictitious pressure Active rockbolts Surface support reaction pressure Tunnel design

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Coupled Cu doping and Z-scheme heterojunction for synergistically enhanced tetracycline photodegradation

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Nano Research 2024年第7期17卷 5937-5948页

作者： Huidong Shen Chunming Yang Song Hong Leiduan Hao Liang Xu Alex W.Robertson zhenyu sun Country State Key Laboratory of Organic-Inorganic Composites College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China Department of Physics University of WarwickCoventry CV 47ALUK

Semiconductor-based photocatalysis by utilizing solar energy for sustainable organic pollutant elimination has been a promising tactic to alleviate environmental ***,the development of robust and efficient photocatalysts to degrade organic pollutants still faces major challenges because of insufficient charge *** we design and fabricate a heterojunction consisting of copper,carbon-modified TiO_(2),and sulfur-doped g-C_(3)N_(4)nanosheets(i.e.,S-C_(3)N_(4)/Cu/C-TiO_(2)).The heterostructure affords a remarkable synergistic photocatalysis for tetracycline hydrochloride degradation,achieving an 82.6%removal efficiency within 30 min under visible light irradiation,about 15.4 and 7.3 times higher than that of S-C_(3)N_(4)and C-TiO_(2),*** superior performance is attributed to the synergy between Cu doping and the Z-scheme heterojunction,which not only enhances the interfacial electric field effect,facilitating charge separation,but also boosts the redox *** charge carrier transfer between Cu/C-TiO_(2)and S-C_(3)N_(4)follows a Z-scheme,as verified by trapping experiments,electron spin-resonance spectroscopy,and density functional theory ***,the tetracycline hydrochloride degradation pathways are enunciated by liquid chromatograph mass spectrometry *** work provides an effective approach for constructing high-performance photocatalysts that have potential in environmental remediation.

关键词： photocatalysis Cu doping Z-scheme heterojunction electrons and holes separation tetracycline degradation

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Effect of Size Change on Mechanical Properties of Monolayer Arsenene

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 206-212页

作者：郭娟刘贵立孙震宇 School of Architecture and Civil Engineering Shenyang University of TechnologyShenyang 110870China

The Young's modulus, shear modulus and Poisson's ratio of monolayer arsenene with different sizes were calculated by finite element method, so as to explore the influence of dimension and orientation on the mechanical properties of monolayer arsenene. The calculation results show that the small size has a significant effect on the mechanical properties of the monolayer arsenene. The smaller the size, the larger the Young's modulus and Poisson's ratio of the monolayer arsenene. The size change has a great influence on the Young's modulus of the arsenene handrail direction, and the Young's modulus of the zigzag direction is not sensitive to the size change. Similarly, the size change has a significant effect on the shear modulus of arsenene in the handrail direction, while the shear modulus in the zigzag direction has no significant effect on its size change. For the Poisson's ratio, the situation is just the opposite, and the effect of the size change on the Poisson's ratio of the arsenene zigzag direction is greater than that of the handrail direction.

关键词： finite element method arsenene size change mechanical properties

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Electrocatalytic Reduction of CO_(2)to CO with Almost 100%Faradaic Efficiency Using Oxygen-Vacancy Enriched Two-Dimensional MgO

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CCS Chemistry 2024年第6期6卷 1477-1486页

作者： Yu Han sunggi An Xinyu Zhan Leiduan Hao Liang Xu Song Hong Dongmin Park Yuxin Chen Yiwen Xu Jiwen Zhao Xinyi Tan Alex W.Robertson Yousung Jung zhenyu sun State Key Laboratory of Organic-Inorganic Composites College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029 Department of Chemical and Biomolecular Engineering(BK21four) Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141 Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081 Department of Physics University of WarwickCoventry

The design and development of cheap,abundant,and efficient electrocatalysts for selective CO_(2)electroreduction is highly desirable yet remains an ongoing ***,we report on our discovery of the use of two-dimensional MgO rich in oxygen vacancies(VO)as an electrocatalyst for the efficient reduction of CO_(2)to yield CO in 1-butyl-3-methylimidazolium hexafluorophosphate dissolved in *** faradaic efficiency toward CO reaches as high as 99.6±0.24%with a current density of up to 40.8 mA cm−*** functional theory calculations illustrate that the introduction of VO in MgO substantially lowers the reaction-free energy for the transformation of ^(*)COO^(−) to ^(*)COOH,the potential determining step,which greatly boosts CO_(2)conversion *** work opens the way to realizing economic and efficient CO_(2)electrolysis of group II metals.

关键词： CO_(2)reduction electrocatalysis CO MgO ionic liquid oxygen-vacancy

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Development of in situ characterization techniques in molecular beam epitaxy

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Journal of Semiconductors 2024年第3期45卷 9-32页

作者： Chao Shen Wenkang Zhan Manyang Li zhenyu sun Jian Tang Zhaofeng Wu Chi Xu Bo Xu Chao Zhao Zhanguo Wang Laboratory of Solid State Optoelectronics Information Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 101804China School of Physics Science and Technology Xinjiang UniversityUrumqi 830046China School of New Energy and Electronics Yancheng Teachers UniversityYancheng 224002China Key Laboratory of Optoelectronic Materials and Devices Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

Ex situ characterization techniques in molecular beam epitaxy(MBE)have inherent limitations,such as being prone to sample contamination and unstable surfaces during sample transfer from the MBE *** recent years,the need for improved accuracy and reliability in measurement has driven the increasing adoption of in situ characterization *** techniques,such as reflection high-energy electron diffraction,scanning tunneling microscopy,and X-ray photoelectron spectroscopy,allow direct observation of film growth processes in real time without exposing the sample to air,hence offering insights into the growth mechanisms of epitaxial films with controlled *** combining multiple in situ characterization techniques with MBE,researchers can better understand film growth processes,realizing novel materials with customized properties and extensive *** review aims to overview the benefits and achievements of in situ characterization techniques in MBE and their applications for material science *** addition,through further analysis of these techniques regarding their challenges and potential solutions,particularly highlighting the assistance of machine learning to correlate in situ characterization with other material information,we hope to provide a guideline for future efforts in the development of novel monitoring and control schemes for MBE growth processes with improved material properties.

关键词： epitaxial growth thin film in situ characterization molecular beam epitaxy(MBE)

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等离子喷涂Cr_(2)O_(3)/8YSZ复合涂层微观组织及抗热冲击性能研究

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西北工业大学学报 2024年第4期42卷 625-633页

作者：袁湖川孙登月孟庆栋田招刚孙振宇燕山大学国家冷轧板带装备及工艺工程技术研究中心河北秦皇岛066004

为了探究Cr_(2)O_(3)/8YSZ复合涂层高温性能,利用等离子喷涂技术在Q235钢表面制备了4种不同混合比例的Cr_(2)O_(3)/8YSZ复合涂层(8YSZ含量分别为50%,30%,20%,0%)。通过热场发射扫描电镜对涂层的形貌进行SEM表征并对涂层的截面元素分布进... 详细信息

为了探究Cr_(2)O_(3)/8YSZ复合涂层高温性能,利用等离子喷涂技术在Q235钢表面制备了4种不同混合比例的Cr_(2)O_(3)/8YSZ复合涂层(8YSZ含量分别为50%,30%,20%,0%)。通过热场发射扫描电镜对涂层的形貌进行SEM表征并对涂层的截面元素分布进行EDS线扫,采用X射线衍射仪分析复合涂层的物相组成,利用表面轮廓仪测量了复合涂层的表面粗糙度,使用全自动显微维氏硬度计对涂层的显微硬度进行测量,采用划痕仪对涂层的抗划伤性能进行对比,利用Gleeble-3800热物理实验模拟机对涂层的抗热冲击性能进行测试,并对热冲击之后的截面形貌进行观察分析。结果表明,当Cr_(2)O_(3)与8YSZ比例为7∶3时,由于8YSZ对垂直裂纹的偏转作用以及涂层内部存在的孔隙和裂纹对热应力的释放作用,该样本涂层具有较好的抗热冲击性能。

关键词：等离子喷涂 Cr_(2)O_(3) 8YSZ 复合涂层抗热冲击性能

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人工智能与实验动画:技术与实验情感的平衡

亚洲学术论坛

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亚洲学术论坛 2024年第2期1卷 48-52页

作者：孙振瑜吉利学院四川成都641423

在探讨人工智能与实验动画的融合时,不得不提及的是:技术与情感表达之间的微妙平衡。实验动画作为一种艺术家思索的表现形式,其核心在于探索和表达人类情感的深层次维度。然而,随着人工智能(AI)技术的融入,实验动画创作面临了一些新的... 详细信息

在探讨人工智能与实验动画的融合时,不得不提及的是:技术与情感表达之间的微妙平衡。实验动画作为一种艺术家思索的表现形式,其核心在于探索和表达人类情感的深层次维度。然而,随着人工智能(AI)技术的融入,实验动画创作面临了一些新的难点。如何在技术进步与实验情感之间找到平衡点,成为当下实验动画领域亟待解决的问题。本文主要以实验动画中实验情感为切入点,结合人工智能语境阐述了AI技术与实验情感的平衡之法,从情感算法、人机协作以及反馈优化三点展开论述,力求为今后实验动画相关研究提供解决思路。

关键词：实验动画人工智能实验情感

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激光雷达在变电站测量中的应用

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农村电气化 2024年第7期 25-30页

作者：孙震宇国网冀北北京送变电有限公司北京房山102401

针对电力系统中变电站运行维修作业和设备运输的安全问题,文章探讨了应用激光雷达的解决方案,并引入了点云处理技术,对激光雷达测量结果进行优化处理,提高了测量效率与准确度。为满足变电站特定环境与测量需求,制定并实施了一套点云处... 详细信息

针对电力系统中变电站运行维修作业和设备运输的安全问题,文章探讨了应用激光雷达的解决方案,并引入了点云处理技术,对激光雷达测量结果进行优化处理,提高了测量效率与准确度。为满足变电站特定环境与测量需求,制定并实施了一套点云处理算法的特殊优化策略,在模拟环境中取得了有效验证。将优化过的激光雷达和点云处理软件成功应用到变电站的实际测量中,通过三维扫描生成了高质量的变电站模型。这一新型测量方式使得维护作业的安全距离得以精确测量,大大提高了作业的安全性。

关键词：激光雷达变电站测量安全距离三维扫描

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两种基于深度网络的股票价格预测方法研究

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现代信息科技 2024年第6期8卷 86-89页

作者：孙震宇云南师范大学数学学院云南昆明650500 云南省现代分析数学及其应用重点实验室云南昆明650500

股票是一种重要的投资渠道,如何更准确地预测股票价格是一个热门的研究课题。由于股票数据的非线性、非平稳以及前后相关等复杂特点,传统的股票价格预测方法已经到达性能瓶颈。随着深度学习方法的兴起,LSTM和GRU等深度神经网络预测模型... 详细信息

股票是一种重要的投资渠道,如何更准确地预测股票价格是一个热门的研究课题。由于股票数据的非线性、非平稳以及前后相关等复杂特点,传统的股票价格预测方法已经到达性能瓶颈。随着深度学习方法的兴起,LSTM和GRU等深度神经网络预测模型受到了极大的关注。基于厦门港务股票和上证指数的历史交易数据,利用了LSTM和GRU两种模型对收盘价进行预测研究,通过5个指标MAE、MSE、RMSE、MAPE和R^(2)给出了模型评价。

关键词：股票价格预测 LSTM模型 GRU模型

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