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Mechanical behavior and damage constitutive model of sandstone under hydro-mechanical (H-M) coupling

International Journal of Mining Science and Technology 2024年第6期34卷 837-853页

作者： tao Tan Chunyang zhang Yanlin Zhao Xiaoshuang Li School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Safety and Health in Metal Mines Maanshan 243000China Sinosteel Maanshan General Institute of Mining Research Co. Ltd.Maanshan 243000China School of Resource&Environment and Safety Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Urban Construction Changzhou UniversityChangzhouJiangsu 213164China

Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under H-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under H-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under H-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to H-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under H-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and H-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under H-M coupling, overcome the inconvenience of existing D-C models

关键词： H-M coupling Water-saturated sandstone Mechanical mechanism Energy evolution D-C model

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A Nitsche-Based Element-Free Galerkin Method for Semilinear Elliptic Problems

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Advances in Applied Mathematics and Mechanics 2024年第1期16卷 24-46页

作者： tao zhang Xiaolin Li School of Mathematics Physics and Data ScienceChongqing University of Science and TechnologyChongqing 401331China School of Mathematical Sciences Chongqing Normal UniversityChongqing 400047China Key Laboratory for Optimization and Control Ministry of Education Chongqing Normal UniversityChongqing 400047China

A Nitsche-based element-free Galerkin(EFG)method for solving semilinear elliptic problems is developed and analyzed in this *** existence and uniqueness of the weak solution for semilinear elliptic problems are proved based on a condition that the nonlinear term is an increasing Lipschitz continuous function of the unknown function.A simple iterative scheme is used to deal with the nonlinear integral *** proved the existence,uniqueness and convergence of the weak solution sequence for continuous level of the simple iterative scheme.A commonly used assumption for approximate space,sometimes called inverse assumption,is *** order error estimates in L 2 and H1 norms are proved for the linear and semilinear elliptic *** the actual numerical calculation,the characteristic distance h does not appear explicitly in the parameterβintroduced by the Nitsche *** theoretical results are confirmed numerically。

关键词： Meshless method element-free Galerkin method Nitsche method semilinear elliptic problem error estimate

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Optimized the vanadium electrolyte with sulfate-phosphoric mixed acids to enhance the stable operation at high-temperature

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 13-26页

作者： Ling Ge tao Liu Yimin zhang Hong Liu School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan 430081China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Hubei Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources Wuhan University of Science and TechnologyWuhan 430081China Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource Wuhan University of Science and TechnologyWuhan 430081China School of Resource and Environmental Engineering Wuhan University of TechnologyWuhan 430070China

Herein, the influence of the concentration design and comprehensive performance of the sulfate-phosphoric mixed acid system electrolyte is investigated to realize an electrolyte that maintains high energy density and stable operation at high temperatures. Static stability tests have shown that VOPO4 precipitation occurs only with vanadium(V) electrolyte. The concentration of vanadium ion of 2.0–2.2 mol·L^(–1), phosphoric acid of 0.10–0.15 mol·L^(–1), and sulfuric acid of 2.5–3.0 mol·L^(–1) are suitable for a vanadium redox flow battery in the temperature range from –20 to 50 ℃. The equations for predicting the viscosity and conductivity of electrolytes are obtained by the response surface method. The optimized electrolyte overcomes precipitation generation. It has 2.8 times higher energy density than the non-phosphate electrolyte, and a coulomb efficiency of 94.0% at 50 ℃. The sulfate-phosphoric mixed acid system electrolyte promotes the electrode reaction process, increases the current density, and reduces the resistance. This work systematically optimizes the concentrations of composition of positive and negative vanadium electrolytes with mixed sulfate-phosphoric acid. It provides a basis for the different valence states and comprehensive properties of sulfate-phosphoric mixed acid system vanadium electrolytes under extreme environments, guiding engineering applications.

关键词： all vanadium redox flow battery mixed-acid vanadium electrolyte concentration optimization response surface methodology high-temperature stability

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Synthesis and applications of carbon nanospheres:A review

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Particuology 2024年第4期87卷 325-338页

作者： Yaqi Yao Jinming Xu Yanqiang Huang tao zhang State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

The synthesis of carbon nanospheres(CNS)has developed rapidly in recent years,and they are widely used owing to the tunability of their porous structures and surface properties and the unique hydrodynamic advantages conferred by their spherical *** review summarizes the methods used to synthesize CNS and their applications in various *** review first describes the four main methods of CNS synthesis,*** template,spray-drying,hydrothermal carbonization,Stöber and chemical vapor depo-sition ***,applications in the fields of energy storage,adsorption,biological medicine,and catalysis are ***,some insights on the development and design of CNS are presented.

关键词： Carbon nanosphere Synthesis Application

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A residual denoising and multiscale attention-based weighted domain adaptation network for tunnel boring machine main bearing fault diagnosis

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Science China(Technological Sciences) 2024年第8期67卷 2594-2618页

作者： ZHONG tao QIN ChengJin SHI Gang zhang ZhiNan tao JianFeng LIU ChengLiang State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

As a critical component of a tunnel boring machine(TBM),the precise condition monitoring and fault analysis of the main bearing is essential to guarantee the safety and efficiency of the TBM cutter ***,under conditions of strong noise and complex working environments,traditional signal decomposition and machine learning methods struggle to extract weak fault features and achieve high fault classification *** address these issues,we propose a novel residual denoising and multiscale attention-based weighted domain adaptation network(RDMA-WDAN)for TBM main bearing fault *** approach skillfully designs a deep feature extractor incorporating residual denoising and multiscale attention modules,achieving better domain adaptation despite significant domain *** residual denoising component utilizes a convolutional block to extract noise features,removing them via residual ***,the multiscale attention module uses a 4-branch convolution and 3 pooling strategy-based channel–spatial attention mechanism to extract multiscale features,concentrating on deep fault *** training,a weighting mechanism is introduced to prioritize domain samples with clear fault *** optimizes the deep feature extractor to obtain common features,enhancing domain adaptation.A low-speed and heavy-loaded bearing testbed was built,and fault data sets were established to validate the proposed *** experiments show that in noise domain adaptation tasks,proposed the RDMA–WDAN significantly improves target domain classification accuracy by 42.544%,23.088%,43.133%,16.344%,5.022%,and 9.233%over dense connection network(DenseNet),squeeze–excitation residual network(SE-ResNet),antinoise multiscale convolutional neural network(ANMSCNN),multiscale attention module-based convolutional neural network(MSAMCNN),domain adaptation network,and hybrid weighted domain adaptation(HWDA).In combined noise and working condition domain a

关键词： tunnel boring machine(TBM) main bearing fault diagnosis domain adaptation antinoise cross working RDMA-WDAN

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Diabetic retinopathy identification based on multi-sourcefree domain adaptation

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1193-1204页

作者： guang-Hua zhang guang-Ping Zhuo Zhao-Xia zhang Bin Sun Wei-Hua Yang Shao-Chong zhang School of Big Data Intelligent Diagnosis&Treatment Industry Taiyuan UniversityTaiyuan 030032Shanxi ProvinceChina Shanxi Key Laboratory of Intelligent Optimization Computing and Blockchain Technology Taiyuan Normal UniversityTaiyuan 030619Shanxi ProvinceChina Shanxi Eye Hospital Taiyuan 030002Shanxi ProvinceChina College of Computer Science and Technology Taiyuan Normal UniversityTaiyuan 030619Shanxi ProvinceChina Shenzhen Eye Institute Shenzhen Eye HospitalJinan UniversityShenzhen 518040Guangdong ProvinceChina

AIM:To address the challenges of data labeling difficulties,data privacy,and necessary large amount of labeled data for deep learning methods in diabetic retinopathy(DR)identification,the aim of this study is to develop a source-free domain adaptation(SFDA)method for efficient and effective DR identification from unlabeled ***:A multi-SFDA method was proposed for DR *** method integrates multiple source models,which are trained from the same source domain,to generate synthetic pseudo labels for the unlabeled target ***,a softmax-consistence minimization term is utilized to minimize the intra-class distances between the source and target domains and maximize the inter-class *** is performed using three color fundus photograph datasets(APTOS2019,DDR,and EyePACS).RESULTS:The proposed model was evaluated and provided promising results with respectively 0.8917 and 0.9795 F1-scores on referable and normal/abnormal DR identification *** demonstrated effective DR identification through minimizing intra-class distances and maximizing inter-class distances between source and target ***:The multi-SFDA method provides an effective approach to overcome the challenges in DR *** method not only addresses difficulties in data labeling and privacy issues,but also reduces the need for large amounts of labeled data required by deep learning methods,making it a practical tool for early detection and preservation of vision in diabetic patients.

关键词： diabetic retinopathy multisource-free domain adaptation pseudo-label generation softmaxconsistence minimization

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A quantum-enhanced magnetometer using a single high-spin nucleus in silicon

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Chinese Physics B 2024年第9期33卷 110-115页

作者： tao Xin Ke zhang Jun Li Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Physikalisch-Technische Bundesanstalt Bundesallee 10038116 BraunschweigGermany Institute of Quantum Precision Measurement State Key Laboratory of Radio Frequency Heterogeneous IntegrationShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg *** particular,quantum probes prepared in nonclassical coherent states have recently been recognized as a useful resource for ***,there has been considerable interest in constructing magnetic quantum sensors that combine high resolution and high ***,we explore a nanoscale magnetometer with quantum-enhanced sensitivity,based on 123Sb(I=7/2)nuclear spin doped in silicon,that takes advantage of techniques of spin-squeezing and coherent *** the optimal squeezed initial state,the magnetic field sensitivity may be expected to approach 6 aT·Hz^(−1/2)·cm^(−3/2) and 603 nT·Hz^(−1/2) at the single-spin *** magnetic sensor may provide a novel sensitive and high-resolution route to microscopic mapping of magnetic fields as well as other applications.

关键词： quantum magnetometer silicon quantum qubit nuclear electrical resonance

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Therapeutic potential of targeting protein tyrosine phosphatases in liver diseases

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Acta Pharmaceutica Sinica B 2024年第8期14卷 3295-3311页

作者： Ao Wang Yi zhang Xinting Lv guang Liang Department of Pharmacy and Institute of Inflammation Zhejiang Provincial Affiliated People’s HospitalHangzhou Medical CollegeHangzhou 310014China Key Laboratory of Natural Medicines of the Changbai Mountain Ministry of EducationYanbian UniversityYanji 133002China Chemical Biology Research Center School of Pharmaceutical SciencesWenzhou Medical UniversityWenzhou 325035China

Protein tyrosine phosphorylation is a post-translational modification that regulates protein structure to modulate demic organisms’homeostasis and *** physiological process is regulated by two enzyme families,protein tyrosine kinases(PTKs)and protein tyrosine phosphatases(PTPs).As an important regulator of protein function,PTPs are indispensable for maintaining cell intrinsic physiology in different systems,as well as liver physiological and pathological *** of PTPs has been implicated in multiple liver-related diseases,including chronic liver diseases(CLDs),hepatocellular carcinoma(HCC),and liver injury,and several PTPs are being studied as drug therapeutic ***,given the regulatory role of PTPs in diverse liver diseases,a collated review of their function and mechanism is ***,based on the current research status of targeted therapy,we emphasize the inclusion of several PTP members that are clinically significant in the development and progression of liver *** an emerging breakthrough direction in the treatment of liver diseases,this review summarizes the research status of PTP-targeting compounds in liver diseases to illustrate their potential in clinical ***,this review aims to support the development of novel PTP-based treatment pathways for liver diseases.

关键词： Tyrosine phosphorylation PTPs Signal transduction CLDs HCC Allosteric inhibitor PROTACs Drug development

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Significant contribution of carbonyls to atmospheric oxidation capacity(AOC)during the winter haze pollution over North China Plain

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Journal of Environmental Sciences 2024年第5期139卷 377-388页

作者： Xue Yang Gen zhang guang Pan Guolan Fan Houyong zhang Xuan Ge Mingyue Du School of Municipal and Environmental Engineering Shandong Jianzhu UniversityJi’nan 250101China State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological SciencesBeijing 100081China Shandong Jinan Ecological Environment Monitoring Center Ji’nan 250101China

Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been clearly *** we measured carbonyl compounds and other trace gasses together with PM_(2.5)over urban Jinan in North China Plain during the *** higher carbonyl concentrations(average:14.63±4.21 ppbv)were found during wintertime haze pollution,about one to three-times relative to those on nonhaze days,with slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)were the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze *** from observational-based model(OBM)with atmospheric oxidation capacity(AOC)indicated that AOC significantly increased with the increasing carbonyls during the winter haze *** photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls *** variation with carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene was further confirmed to be the major precursor for *** study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls would be an effective way to mitigate haze pollution in urban area of the NCP region.

关键词： Carbonyls Haze Observation-based model Source apportionment Atmospheric oxidation capacity

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How to achieve energy efficiency in buildings without compromising indoor air quality:A case study on enthalpy exchangers

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Science China(Technological Sciences) 2024年第9期67卷 2648-2658页

作者： LI Hao zhang tao LIU XiaoHua Department of Building Science Tsinghua UniversityBeijing 100084China

As a representative heat recovery device,the fixed-plate enthalpy exchanger possesses the advantages of high recovery effectiveness,low pressure drop,and small space ***,indoor contaminants may transfer to fresh air through the enthalpy exchanger simultaneously,causing cross-contamination ***,the cross-contamination risk of the fixed-plate enthalpy exchanger has been under-researched in previous *** a result,this study experimentally investigates the energy performance,formaldehyde and ammonia transfer rates of paper-based and membrane-based enthalpy *** results illustrate that the enthalpy recovery effectiveness of the plate exchangers ranges from 60%–85%.The formaldehyde transfer rate through the exchangers varies from 5%–23%,and the ammonia transfer rate is 0–15%.The high effectiveness and low contaminant transfer rates are conducive to the promising application of the fixed-plate enthalpy *** addition,the energy reclaimed increases with the increase of the absolute indoor-outdoor enthalpy *** formaldehyde and ammonia transfer rates and cross-contamination risk slightly decrease with increasing temperature but significantly increase with increasing ***,the experimental results demonstrate that the contaminant transfer rates through the membranebased exchanger are lower than those of the paper-based *** study provides a reference for the fixed-plate enthalpy exchanger design in practical applications.

关键词： building energy efficiency enthalpy recovery heat recovery effectiveness cross-contamination

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