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Construction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： Yong ZHAO Tingyu zhu Li yu Ming lu Sichuan–Xizang Railway Co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the ***,a comprehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to control the heat release of hot *** ventilation,ice chillers and other applicable measures are used to control the ambient ***,a monitoring and early warning system is established to prevent *** cooling strategy has been applied in the field with good results.

关键词： high geothermal tunnels cooling strategy comprehensive cooling measures safety and security

Accurate electron affinity of atomic cerium and excited states of its anion

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Chinese Physics B 2020年第7期29卷 275-280页

作者： Xiao-Xi Fu Ru-Lin Tang yu-zhu lu Chuan-Gang Ning Department of Physics State Key Laboratory of Low-Dimensional Quantum PhysicsTsinghua UniversityBeijing 100084China Collaborative Innovation Center of Quantum Matter Beijing 100084China

Electron affinities(EA)of most lanthanide elements still remain unknown owing to their relatively lower EA values and the fairly complicated electronic *** the present work,we report the high-resolution photoelectron spectra of atomic cerium anion Ce−using the slow electron velocity-map imaging method in combination with a cold ion *** electron affinity of Ce is determined to be 4840.62(21)cm^-1 or 0.600160(26)***,several excited states of Ce(^4H9/2,^4I9/2,^2H9/2,^2G9/2,^2G7/2,^4H13/2,^2F5/2,and ^4I13/2)are observed.

关键词： electron affinity cerium anion slow electron velocity-map imaging cold ion trap

Recent Progress in Two-dimensional Nanomaterials Following Graphene for Improving Fire Safety of Polymer(Nano)composites

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Chinese Journal of Polymer Science 2021年第8期39卷 935-956,I0004页

作者： Wei Cai Bi-Bo Wang Xin Wang yu-lu zhu Zhao-Xin Li Zhou-Mei Xu Lei Song Wei-Zhao Hua yuan Hua State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230000China Suzhou Advanced Research Institute University of Science and Technology of ChinaSuzhou 215000China

The high fire safety of polymer nanocomposites is being pursued by research institutions around the *** addition to intrinsic flame retardancy strategy,the additive-type flame retardants have attracted increasing attention due to low commercial cost and easy fabrication ***,traditional additive-type flame retardants usually need high addition amount to achieve a desirable effect which causes many side-effects on the overall performance of polymer materials,such as deteriorated mechanical property and *** present two-dimensional(2D)nanomaterials have also been applied to reduce the fire hazards of polymer(nano)composites with the coupling of barrier function and catalysis as well as carbonization *** though most research work mainly focus on graphene-based flame retardants,more emerging two-dimensional nanomaterials are taking away research attention,due to their complementary and unique properties,mainly including hexagonal boron nitride(h-BN),molybdenum disulfide(MoS2),metal organic frameworks(MOF),carbon nitride(CN),titanium carbide(MXene)and black phosphorene(BP).In this review,except for graphene,the flame retardant mechanism involving different layered nanomaterials are also ***,the functionalization method and flame retardancy effect of different layered nanomaterials are emphatically discussed for offering an effective reference to solve the fire hazards of polymer ***,this work objectively evaluates the practical significance of polymer/layered nanomaterials composites for industrial application.

关键词： Polymer(nano)composites Layered nanomaterials Fire safety Flame retardant mechanism

Spinal Vertebral Fracture Detection and Fracture Level Assessment Based on Deep Learning

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Computers, Materials & Continua 2024年第4期79卷 1377-1398页

作者： yuhang Wang Zhiqin He Qinmu Wu Tingsheng lu yu Tang Maoyun zhu The Electrical Engineering College Guizhou UniversityGuiyang550025China Guizhou Provincial Orthopedics Hospital Guiyang550025China

This paper addresses the common orthopedic trauma of spinal vertebral fractures and aims to enhance doctors’diagnostic ***,a deep-learning-based automated diagnostic systemwithmulti-label segmentation is proposed to recognize the condition of vertebral *** whole spine Computed Tomography(CT)image is segmented into the fracture,normal,and background using U-Net,and the fracture degree of each vertebra is evaluated(Genant semi-qualitative evaluation).The main work of this paper includes:First,based on the spatial configuration network(SCN)structure,U-Net is used instead of the SCN feature extraction *** attention mechanismandthe residual connectionbetweenthe convolutional layers are added in the local network(LN)*** filtering is added in the global network(GN)stage,and each layer of the LN decoder feature map is filtered separately using dot product,and the filtered features are re-convolved to obtain the GN output ***,a network model with improved SCN(M-SCN)helps automatically localize the center-of-mass position of each vertebra,and the voxels around each localized vertebra were clipped,eliminating a large amount of redundant information(e.g.,background and other interfering vertebrae)and keeping the vertebrae to be segmented in the center of the *** segmentation of the clipped portion was subsequently performed using *** paper uses VerSe’19,VerSe’20(using only data containing vertebral fractures),and private data(provided by Guizhou Orthopedic Hospital)for model training and *** with the original SCN network,the M-SCN reduced the prediction error rate by 1.09%and demonstrated the effectiveness of the improvement in ablation *** the vertebral segmentation experiment,the Dice Similarity Coefficient(DSC)index reached 93.50%and the Maximum Symmetry Surface Distance(MSSD)index was 4.962 mm,with accuracy and recall of 95.82%and 91.73%,*** vertebrae w

关键词： Deep learning vertebral fracture detection medical image processing

Using Machine Learning to Identify and Optimize Sensitive Parameters in Urban Flood Model Considering Subsurface Characteristics

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International Journal of Disaster Risk Science 2024年第1期15卷 116-133页

作者： Hengxu Jin yu Zhao Pengcheng lu Shuliang Zhang Yiwen Chen Shanghua Zheng Zhizhou zhu Key Laboratory of VGE of Ministry of Education Nanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

This study presents a novel method for optimizing parameters in urban flood models,aiming to address the tedious and complex issues associated with parameter ***,a coupled one-dimensional pipe network runoff model and a two-dimensional surface runoff model were integrated to construct an interpretable urban flood ***,a principle for dividing urban hydrological response units was introduced,incorporating surface attribute *** K-means algorithm was used to explore the clustering patterns of the uncertain parameters in the model,and an artificial neural network(ANN)was employed to identify the sensitive ***,a genetic algorithm(GA) was used to calibrate the parameter thresholds of the sub-catchment units in different urban land-use zones within the flood *** results demonstrate that the parameter optimization method based on K-means-ANN-GA achieved an average Nash-Sutcliffe efficiency coefficient(NSE) of *** to the ANN-GA and K-means-deep neural networks(DNN) methods,the proposed method better characterizes the runoff generation and flow *** study demonstrates the significant potential of combining machine learning techniques with physical knowledge in parameter optimization research for flood models.

关键词： Artifcial neural network Coupled urban fooding model Genetic algorithm K-means algorithm Subcatchment delineation Uncertain parameters

Topological Stability and Entropy for Certain Set-valued Maps

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Acta Mathematica Sinica,English Series 2024年第4期40卷 962-984页

作者： yu ZHANG yu Jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the dynamics(including shadowing property,expansiveness,topological stability and entropy)of several types of upper semi-continuous set-valued maps are mainly considered from differentiable dynamical systems points of *** is shown that(1)if f is a hyperbolic endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has theε-shadowing property,and moreover,if f is an expanding endomorphism then there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has the Lipschitz shadowing property;(2)when a set-valued map F is generated by finite expanding endomorphisms,it has the shadowing property,and moreover,if the collection of the generators has no coincidence point then F is expansive and hence is topologically stable;(3)if f is an expanding endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that h(F_(f,U,ε))=h(f);(4)when F is generated by finite expanding endomorphisms with no coincidence point,the entropy formula of F is ***,the dynamics of the set-valued maps based on discontinuous maps on the interval are also considered.

关键词： Set-valued map orbit space hyperbolic endomorphism perturbation shadowing expansiveness topological stability entropy

Implications for fault reactivation and seismicity induced by hydraulic fracturing

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Petroleum Science 2024年第2期21卷 1081-1098页

作者： Zi-Han Sun Ming-Guang Che Li-Hong zhu Shu-Juan Zhang Ji-yuan lu Chang-yu Jin Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent TechnologyNortheastern UniversityShenyang110819LiaoningChina Research Institute of Petroleum Exploration&Development PetroChina Company LimitedBeijing100084China The Exploration and Development Research Institute of Daqing Oilfield Limited Company Daqing163458HeilongjiangChina

Evaluating the physical mechanisms that link hydraulic fracturing(HF) operations to induced earthquakes and the anticipated form of the resulting events is significant in informing subsurface fluid injection operations. Current understanding supports the overriding role of the effective stress magnitude in triggering earthquakes, while the impact of change rate of effective stress has not been systematically addressed. In this work, a modified critical stiffness was brought up to investigate the likelihood, impact,and mitigation of induced seismicity during and after hydraulic fracturing by developing a poroelastic model based on rate-and-state fraction law and linear stability analysis. In the new criterion, the change rate of effective stress was considered a key variable to explore the evolution of this criterion and hence the likelihood of instability slip of fault. A coupled fluid flow-deformation model was used to represent the entire hydraulic fracturing process in COMSOL Multiphysics. The possibility of triggering an earthquake throughout the entire hydraulic fracturing process, from fracturing to cessation, was investigated considering different fault locations, orientations, and positions along the fault. The competition between the effects of the magnitude and change rate of effective stress was notable at each fracturing stage. The effective stress magnitude is a significant controlling factor during fracturing events, with the change rate dominating when fracturing is suddenly started or stopped. Instability dominates when the magnitude of the effective stress increases(constant injection at each fracturing stage) and the change rate of effective stress decreases(the injection process is suddenly stopped). Fracturing with a high injection rate, a fault adjacent to the hydraulic fracturing location and the position of the junction between the reservoir and fault are important to reduce the Coulomb failure stress(CFS) and enhance the critical stiffness as

关键词： Hydraulic fracturing Coulomb failure stress Rate-and-state fraction model Linear stability analysis Critical stiffness Seismically induced fault

Radiation Spectral Analysis of 3D Dust Molecular Clusters(PAHs)and Peptoids under Ionization and Electric Field in ISM

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Research in Astronomy and Astrophysics 2024年第1期24卷 70-77页

作者： Ruiqing Wu Chunhua zhu Guoliang Lü Xiaojiao Zhang Xizhen lu Jinlong yu Wujin Chen Mengqiu Long School of Physics and Electronics Central South UniversityChangsha 410083China School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China School of Microelectronics and Physics Hunan University of Technology and BusinessChangsha 410205China College of Mechanical and Electronic Engineering Tarim UniversityAlar 843300China School of Medicine Xinjiang Medical UniversityUrumqi 830011China

Polycyclic aromatic hydrocarbons(PAHs),PANHs,and peptoids dust spectral calculations from the interstellar medium(ISM)are important for dust observations and *** goal is to calculate the radiation spectrum of spherical PAHs dust clusters in a vacuum containing ionized and applied in the presence of an electric *** propose a new simple computational model to calculate the size of three-dimensional spherical dust clusters formed by different initial dust *** the Vienna Ab-initio Simulation Package code,the density functional theory with the generalized approximation was used to calculate the electron density gradient and obtain the radiation spectrum of *** the radius of spherical dust clusters is~[0.009-0.042]μm,the dust radiation spectrum agrees well with the Z=0.02 mMMP stellar spectra,and the PAHs radiation spectrum of NGC 4676 at wavelengths of(0-5]μm and(5-10]μm,*** the ionized state,the N-PAH,C_(10)H_(9)N,2(C_(4)H_(4))^(1+),and peptoids 4(CHON),(C_(8)H_(10)N_(2)O_(5))^(1+)dust clusters at 3.3μm,while the 2(C_(22)H_(21)N_(3)O_(2))^(1+),4(CHON)dust clusters at 5.2μm have obvious *** is a characteristic of part of PAHs and peptoids clusters radiation at the nearinfrared wavelength of 2μ***,especially after applying an electric field to the dust,the emission spectrum of the dust increases significantly in the radiation wavelength range[3-10]μ***,the dust clusters of PAHs,PANHs,and peptoids of the radius size~[0.009-0.042]μm are likely to exist in the ISM.

关键词： ISM:structure ISM:molecules radiation mechanisms:general (ISM:)dust extinction

Cooperative game penetration guidance for multiple hypersonic vehicles under safety critical framework

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Chinese Journal of Aeronautics 2024年第1期37卷 247-255页

作者： Jieqing CHEN Ruisheng SUN yu lu School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China

The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced with space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framework is *** this scheme,a multiHV cooperative game model is proposed in a minimum optimization form which can simplify the solving process and accelerate the computing ***,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear *** order to obtain better performance of guidance strategy,a composite guidance law under the safety critical control framework is presented to allocate guidance strategies appropriately in the whole *** is shown that the proposed scheme can guarantee successful penetration while avoiding threat ***,a comparative simulation with a two-on-three game is conducted to verify the effectiveness of the proposed method.

关键词： Hypersonic vehicles Safety critical control Penetration game Space constraints Cooperative guidance