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Frost heaving force considering synchronous damage to tunnel lining and surrounding rocks under freeze—thaw cycles

Journal of Mountain Science 2023年第4期20卷 1131-1146页

作者： LIU wen-jun LING Tong-hua HE wen-chao LIU Xian-jun School of Civil Engineering Changsha University of Science and TechnologyChangsha410114China Logistics and Infrastructure Department Huaihua UniversityHuaihua418099China

In areas with seasonal freezing,when the tunnel lining concrete is saturated with water infiltrating the interior,the lining and the surrounding rocks will simultaneously ***,the current calculation of the frost heaving force fails to consider the synchronous damage to the lining and surrounding rocks under freeze-thaw ***,as per the elastic calculation model of the frost heaving force and model of steady-state heat transfer of circular tunnels,this study introduces the frost heaving rate of lining and surrounding ***,the analytical solution of frost heaving force is obtained for simultaneous frost heaving of lining and surrounding rocks under any steady-state temperature ***,based on the fracture theory and meso-damage mechanics,the damage variables of lining and surrounding rocks under freeze-thaw cycles are extracted,representing their elastic modulus and ***,the formula of frost heaving force for synchronous damage to the lining and surrounding rocks at any steady-state temperature field is *** calculation results demonstrate that the lower the temperature inside the lining,the greater the frost heaving *** the increasing number of freeze-thaw cycles,frost heaving force tends to gradually increase initially,reaching a peak value at 85 freeze-thaw cycles,decreasing to 80%of the peak value at 140 cycles before reaching a constant *** lining participates in frost heaving,increasing the frost heaving *** initial increase rate of frost heaving force is 15.7%.Changing the fitting coefficients s1 and s2 of the lining and surrounding rocks can effectively control the magnitude of the frost heaving force in the tunnels.

关键词： Freeze-thaw cycles Frost heaving force Concrete lining Tunnel surrounding rock Synchronous damage

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Numerical Investigations on Harbor Oscillations Induced by Falling Objects

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China Ocean Engineering 2023年第3期37卷 458-470页

作者： GAO jun-liang BI wen-jing ZHANG Jian ZANG jun School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources Guangzhou 510611China Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYUK

In this paper,the open-sourced computational fluid dynamics software,OpenFOAM~?,is used to study the fluctuation phenomenon of the water body inside a horizontally one-dimensional enclosed harbor basin with constant water depth triggered by falling wedges with various horizontal falling positions,initial falling velocities and *** on both Fourier transfo rm analysis and wavelet spectrum analysis for the time series of the free surface elevations inside the harbor basin,it is found for the first time that the wedge falling inside the harbor can directly trigger harbor *** influences of the three factors(including the horizontal falling position,the initial falling velocity,and the mass)on the response amplitudes of the lowest three resonant modes are also *** results show that when the wedge falls on one of the nodal points of a resonant mode,the mode would be remarkably ***,when the wedge falls on one of the anti-nodal points of a resonant mode,the mode would be evidently *** initial falling velocity of the wedge mainly has a remarkable effect on the response amplitude of the most significant mode,and the latter shows a gradual increase trend with the increase of the *** for the other two less significant modes,their response amplitudes fluctuate around certain constant values as the initial falling velocity *** general,the response amplitudes of all the lowest three modes are shown to gradually increase with the mass of the wedge.

关键词： harbor oscillations seiches falling objects resonant mode response amplitude

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A Study on the Properties of Resin Transfer Molding Cyanate Ester and Its T800 Grade Carbon Fiber Composites

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Fluid Dynamics & Materials Processing 2019年第1期15卷 27-37页

作者： Qiuren ou Peijun Ji jun Xiao Ling Wu College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China Research Institute of special Aerospace Materials and Processing Technology Beijing100074China

The properties of resin transfer molding(RTM)cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer,differential scanning calorimetry(DSC),FT-IR,dynamic mechanical analyzer(DMA),thermal gravimetric analysis(TGA),mechanical property testing,and scanning electron microscopy(SEM).The results showed that the temperature of cyanate ester suitable for RTM process was 70℃.Curing process of the resin was 130℃/2 h+160℃/2 h+200℃/2 h+220℃/4 *** transition temperature and heat decomposition temperature of the cured resin are 289℃and 415℃,*** properties of T800/RTM cyanate composites are 13.5%higher than that of T700/RTM cyanate composites and equal to that of T800/Prepreg cyanate *** of T800/RTM cyanate composites was proved to be 291℃.Fracture pattern of the composites was flat,which proved excellent interface properties between fiber and resin in this composite.

关键词： RTM cyanate ester viscosity glass transition temperature heat decomposition temperature mechanical properties

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Construction of fault diagnosis system for control rod drive mechanism based on knowledge graph and Bayesian inference

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Nuclear Science and Techniques 2023年第2期34卷 58-75页

作者： Xue‑jun Jiang wen Zhou Jie Hou Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

Knowledge graph technology has distinct advantages in terms of fault *** this study,the control rod drive mechanism(CRDM)of the liquid fuel thorium molten salt reactor(TMSR-LF1)was taken as the research object,and a fault diagnosis system was proposed based on knowledge *** subject–relation–object triples are defined based on CRDM unstructured data,including design specification,operation and maintenance manual,alarm list,and other forms of expert *** this study,we constructed a fault event ontology model to label the entity and relationship involved in the corpus of CRDM fault events.A three-layer robustly optimized bidirectional encoder representation from transformers(RBT3)pre-training approach combined with a text convolutional neural network(TextCNN)was introduced to facilitate the application of the constructed CRDM fault diagnosis graph database for fault *** RBT3-TextCNN model along with the Jieba tool is proposed for extracting entities and recognizing the fault query intent *** on the dataset collected from TMSR-LF1 CRDM fault diagnosis unstructured data demonstrate that this model has the potential to improve the effect of intent recognition and entity ***,a fault alarm monitoring module was developed based on WebSocket protocol to deliver detailed information about the appeared fault to the operator ***,the Bayesian inference method combined with the variable elimination algorithm was proposed to enable the development of a relatively intelligent and reliable fault diagnosis ***,a CRDM fault diagnosis Web interface integrated with graph data visualization was constructed,making the CRDM fault diagnosis process intuitive and effective.

关键词： CRDM Knowledge graph Fault diagnosis Bayesian inference RBT3-TextCNN Web interface

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Root canal therapy combined with endoscopic sinus surgery for odontogenic sinusitis:Efficacy comparison in a cohort study

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World Journal of Clinical Cases 2025年第5期13卷 13-21页

作者： jun-wen Xiao Ping Yu Zhang Zhao Department of Stomatology Wuhan No.9 HospitalWuhan 430081Hubei ProvinceChina Department of Otorhinolaryngology People's Hospital of Xishui CountyHuanggang 438200Hubei ProvinceChina Department of Otorhinolaryngology Hubei No.3 People’s Hospital of Jianghan UniversityWuhan 430033Hubei ProvinceChina

BACKGRouND Odontogenic maxillary sinusitis,often triggered by dental issues like periapical periodontitis,significantly contributes to chronic sinusitis,mainly affecting adults around 50 years old,emphasizing the need for a multidisciplinary diagnostic and treatment *** To investigate the therapeutic effect and clinical value of root canal therapy combined with nasal endoscopic surgery compared with simple root canal the-rapy in the treatment of severe odontogenic maxillary sinusitis caused by peria-pical *** The clinical data,diagnosis,and treatment of 200 patients with severe odonto-genic maxillary sinusitis caused by periapical periodontitis from October 2020 to October 2021 were analyzed *** them,63 patients were treated with simple root canal therapy as the control group,and 137 patients were treated with root canal therapy combined with nasal endoscopic surgery as the observation *** therapeutic effect,Lund-Kennedy endoscopic score,paranasal sinus Lund-Mackay score,complication rate,recurrence rate,and patient satisfaction were compared between the two *** First,we compared the effective rates:23 cases were cured,22 were improved,and 8 were ineffective in the control group,yielding a total effective rate of 84.90%.Meanwhile,97 cases were cured,34 improved,and 6 were ineffective in the observation group,resulting in a total effective rate of 95.62%.The observation group had a higher total effective rate compared with the control group(P0.05)was observed in this score between the two *** treatment,the Lund–Kennedy endoscopic score decreased in both *** Lund–Kennedy endoscopic score of the observation group at 3 and 6 mo after treatment was lower compared to that of the control group(P<0.05).Third,we compared the Lund–Mackay score of paranasal *** treatment,there was no si

关键词： Root canal therapy Nasal endoscopic surgery Periapical periodontitis Odontogenic maxillary sinusitis Therapeutic effect Clinical value

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Buckling of a stiff thin film on a compliant substrate under anisotropic biaxial prestrain

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Science China(Physics,Mechanics & Astronomy) 2016年第2期59卷 57-66页

作者： Zhi Cheng ou Xiao Hu Yao Xiao Qing Zhang Xue jun Fan School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 51064China Department of Mechanical Engineering Lamar UniversityBeaumont 77710USA

The structure of stretchable electronics is based on the buckling of a thin film on a compliant substrate. Under anisotropic biaxial prestrains, this structure may buckle into several patterns, including cylindrical, checkerboard, and undulating patterns. The displacement and energy of each pattern are deduced analytically. By comparing their minimum potential energies, the critical buckling condition of each pattern is determined. After secondary bifurcation, the checkerboard pattern occurs just above the critical prestrains, but the undulating pattern dominates other regions. The buckling amplitude and wavenumber of the undulating pattern are shown under biaxial prestrains. Even if the structure is under equi-biaxial prestrains, it may buckle into an asymmetric undulating pattern.

关键词： film substrate buckling biaxial anisotropic undulating

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Microstructure and microsegregation of directionally solidified Ti–45Al–8Nb alloy with different solidification rates

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Rare Metals 2016年第1期35卷 70-76页

作者： Xiang-jun Xu Lin Song Xiao-ou Jin Dong-Dong Han Xin Wang jun-Pin Lin Materials and Chemistry School Zhongyuan University of Technology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing School of Architecture and Engineering Heilongjiang University

Microstructure and microsegregation of directionally solidified Ti-45Al-8Nb alloy were investigated by scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and electron probe microanalyzer（EPMA）.For the alloy solidified at the solidification rates（v） ranging from 10 to 400 μm·s^（-1）,the microstructure of the mushy zone exhibits a cellular-dendritic structure at lower growth rate（v=10-50 μm·s^（-1）） and a typical dendritic morphology at higher growth rate（v = 100-400 μm·s^（-1））.The relationship between primary dendrite arm spacing（λ_1）and v is λ_1=1.08×10~3v^（-0.35）.Al and Nb elements segregate at interdendritic zone and in the dendritic core,*** solid of mushy zone,a relatively flat concentration profile is observed for the typical dendrite structure,and Nb enriches in B2 phase induced by β→α＋β*** content of B2 phase is hardly affected by *** extent of microsegregation in steady-state zone decreases at a lower growth rate because holding the samples at higher temperature after solidification for a long time can homogenize the solid effectively.

关键词： Nb-containing TiAl alloy Solidification Microstructure Microsegregation

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A Note on Lower Bound of Centered L_2 -discrepancy on Combined Designs

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Acta Mathematica Sinica,English Series 2012年第4期28卷 793-800页

作者： Yi Ju LEI Zu jun ou Hong QIN Na Zou Department of Mathematics Xinxiang University Faculty of Mathematics and Statistics Central China Normal University College of Mathematics and Computer Science Jishou University School of Statistics and Mathematics Zhongnan University of Economics and Law

This note provides a theoretical justification of optimal foldover plans in terms of uniformity. A new lower bound of the centered Lu-discrepancy values of combined designs is obtained, which can be used as a benchmark for searching optimal foldover plans. our numerical results show that this lower bound is sharper than existing results when more factors reverse the signs in the initial design. Keywords Centered L2-discrepancy, optimal foldover plan, uniformity, uniformity pattern

关键词： Centered L2-discrepancy optimal foldover plan uniformity uniformity pattern

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Impact of travel speed on the microstructure and mechanical properties of adjustable-gap bobbin-tool friction stir welded Al–Mg joints

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 710-717页

作者： Dong Wu wen-ya Li Yan-jun Gao jun Yang Quan wen Nektarios Vidakis Achillefs Vairis State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Travel TechnologiesNorthwestern Polytechnical UniversityXi'an 710072China Capital Aerospace Machinery Company Beijing 100076China Department of Mechanical Engineering Hellenic Mediterranean UniversityHeraklionCrete 71004Greece

The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this *** microstructure was studied using optical microscopy and electron backscatter diffraction(EBSD).Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical *** joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed *** EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization *** attention was given to the relationship between the local microstructure and mechanical *** measurements show that the average hardness of the stir zone(SZ) was greater than that of the base material, which was only affected slightly by the travel *** tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.

关键词： friction stir welding bobbin-tool aluminum alloy microstructure mechanical properties adjustable-gap

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Nonlinear Degenerate Parabolic Equation with Nonlinear Boundary Condition

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Acta Mathematica Sinica,English Series 2005年第4期21卷 847-854页

作者： wen jun SUN Shu WANG LCP Institute of Applied Physics and Computational Mathematics P. O. Box 8009 Beijing 100080 P. R. China College of Applied Science Beijing University of Technology Ping Le Yuan Chao Yang District Beijing 100022 P. R. China

In this paper, we obtain the necessary and sufficient conditions on the global existence of all positive （weak） solutions to a nonlinear degenerate parabolic equation with nonlinear boundary condition.

关键词： Nonlinear degenerate parabolic equation Global existence Blow-up

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