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A whole process damage constitutive model for layered sandstone under uniaxial compression based on Logistic function

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Journal of Central South University 2024年第7期31卷 2411-2430页

作者： LIU Dong-qiao GUO yun-peng LING Kai LI jie-yu State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China

Bedding structural planes significantly influence the mechanical properties and stability of engineering rock *** study conducts uniaxial compression tests on layered sandstone with various bedding angles(0°,15°,30°,45°,60°,75°and 90°)to explore the impact of bedding angle on the deformational mechanical response,failure mode,and damage evolution processes of *** develops a damage model based on the Logistic equation derived from the modulus’s degradation considering the combined effect of the sandstone bedding dip angle and *** model is employed to study the damage accumulation state and its evolution within the layered rock *** research also introduces a piecewise constitutive model that considers the initial compaction characteristics to simulate the whole deformation process of layered sandstone under uniaxial *** results revealed that as the bedding angle increases from 0°to 90°,the uniaxial compressive strength and elastic modulus of layered sandstone significantly decrease,slightly increase,and then decline *** corresponding failure modes transition from splitting tensile failure to slipping shear failure and back to splitting tensile *** indicated by the modulus’s degradation,the damage characteristics can be categorized into four stages:initial no damage,damage initiation,damage acceleration,and damage deceleration *** theoretical damage model based on the Logistic equation effectively simulates and predicts the entire damage evolution ***,the theoretical constitutive model curves closely align with the actual stress−strain curves of layered sandstone under uniaxial *** introduced constitutive model is concise,with fewer parameters,a straightforward parameter determination process,and a clear physical *** study offers valuable insights into the theory of layered rock mechanics and holds implications for ensuring the safety of rock engineering.

关键词： layered sandstone uniaxial compression damage evolution Logistic function constitutive model

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HPLC Fingerprint Combined with Chemometrics and Network Pharmacology for Q-Markers Prediction Analysis of Saposhnikovia divaricata

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Journal of Analysis and Testing 2024年第1期8卷 83-94页

作者： Renguo Zhang Xinjian Liu Tong Wang jie yu Mengyuan Wang Jianmin Sun Xueling yu Na Niu Ligang Chen College of Chemistry Chemical Engineering and Resource UtilizationKey Laboratory of Forest Plant EcologyNortheast Forestry UniversityHarbin 150040China

Saposhnikovia divaricata(SD)has high medicinal and edible value,but relatively little research has been done on its qual-ity markers(Q-markers).To further clarify the Q-markers of SD with their corresponding pharmacodynamic *** this experiment,14 batches of SD were identified and screened for Q-marker candidate components using a combination of HPLC fingerprint with similarity analysis,principal component analysis,hierarchical cluster analysis,and partial least squares discriminant ***,network pharmacology was used to predict Q-markers and core *** results showed that 5-O-methylvisammioside,cimifugin,and prim-O-glucosylcimifugin could be used as Q-markers of SD;while,MAPK1,MAPK3,PIK3CA,JUN,and MAPK8 were the core targets of SD for drug *** further evaluate the bind-ing efficiency of Q-markers,molecular docking of the main active ingredients of SD to the core targets was *** results showed that the compounds bind well to their targets,and binding energies were all less than-5 kcal/*** Q-markers obtained from the screening were closely related to the core target genes,which could achieve therapeutic effects by modulating the relevant signaling *** study offers a reference for the establishment of a set of quality control evaluation system for SD potential Q-markers prediction analysis,and lays the foundation for elucidating the mechanism of actionunderlying itspharmacodynamic substance.

关键词： Saposhnikovia divaricata Q-markers Fingerprint Chemometrics Network pharmacology Molecular docking

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First Record of Middle Eocene Elephant Ancestors’Footprints in the Gonjo Basin,East Tibet Plateau

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Journal of Earth Science 2024年第4期35卷 1224-1235页

作者： Asma Tahir Huazhou yao Junaid Khan Yangui Li He Zhao yue yu Tang yuan Institute of Geological Survey China University of GeosciencesWuhan430074China Wuhan Center China Geological SurveyWuhan430205China State Key Laboratory of Geological Processes and Mineral Resources Wuhan430078China Chengdu Center China Geological SurveyChengdu610081China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

It is the first time that the fossil footprints of a group of Middle Eocene elephant ancestors have been discovered in the Gonjo Basin,East Tibet *** Gonjo Formation is attributed to the Middle Eocene Epoch(U-Pb age=44.7±1.2 Ma)and consists mainly of purplish-red,medium-to coarse-grained sandstones,siltstones interbedded with mudstones,and conglomerates with sedimentary structures like ripple marks,rip-up clasts,and trough-cross bedding,suggesting fluvial-lacustrine *** group of fossil footprints has a characteristic oval-concave shape,and the toe impressions are *** fossil footprints are overstepped with a pockmarked texture resembling Proboscipeda *** than 165 fossil footprints of the group are relatively well-preserved with different diameters,which is evidence of highly social behavior and trackmakers of different ages,including calves,juveniles,adolescents,and *** size frequency of the fossil footprints enabled us to deduce the body mass,shoulder height,and hip-height distribution of the trackmakers that crossed the East Tibet Plateau 44.7 Ma *** trackmakers comprised an estimated average hip-height of 111.8 cm,an average shoulder height of 172.8 cm for males/155.9 cm for females,and an average body mass of approximately 1218.1 kg for males/907.8 kg for *** abundance of fossil footprints reveals that in the Middle Eocene Epoch,the environment was extraordinarily conducive for the elephant ancestors to live in the East Tibet region.

关键词： Proboscipeda enigmatica East Tibet Plateau Gonjo Formation fossil footprints fluvial-lacustrine

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Development of a scintillating-fiber-based beam monitor for the coherent muon-to-electron transition experiment

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Nuclear Science and Techniques 2024年第4期35卷 156-164页

作者： yu Xu yun-Song Ning Zhi-Zhen Qin yao Teng Chang-Qing Feng Jian Tang yu Chen Yoshinori Fukao Satoshi Mihara Kou Oishi School of Physics Sun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China High Energy Accelerator Research Organization(KEK) Ibaraki 305‑0801Japan Department of Physics Imperial College LondonLondon SW72AZUK

The coherent muon-to-electron transition(COMET)experiment is a leading experiment for the coherent conversion of μ^(-)N→e^(-)N using a high-intensity pulsed muon beamline,produced using innovative slow-extraction ***,it is critical to measure the muon beam *** set up a muon beam monitor(MBM),where scintillating fibers woven in a cross shape were coupled to silicon photomultipliers to measure the spatial profile and timing structure of the extracted muon beam for the *** MBM detector was tested successfully with a proton beamline at the China Spallation Neutron Source and took data with good performance in the commissioning *** development of the MBM,including its mechanical structure,electronic readout,and beam measurement results,are discussed.

关键词： Beam instrumentation Profile monitor Scintillating fiber Silicon photomultipliers

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System error iterative identification for underwater positioning based on spectral clustering

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Journal of Systems Engineering and Electronics 2024年第4期35卷 1028-1041页

作者： LU yu WANG Jiongqi HE Zhangming ZHOU Haiyin XING yao ZHOU Xuanying College of Sciences National University of Defense TechnologyChangsha 410073China

The observation error model of the underwater acous-tic positioning system is an important factor to influence the positioning accuracy of the underwater *** the position inconsistency error caused by considering the underwater tar-get as a mass point,as well as the observation system error,the traditional error model best estimation trajectory(EMBET)with little observed data and too many parameters can lead to the ill-condition of the parameter *** this paper,a multi-station fusion system error model based on the optimal polynomial con-straint is constructed,and the corresponding observation sys-tem error identification based on improved spectral clustering is ***,the reduced parameter unified modeling for the underwater target position parameters and the system error is achieved through the polynomial *** a multi-sta-tion non-oriented graph network is established,which can address the problem of the inaccurate identification for the sys-tem ***,the similarity matrix of the spectral cluster-ing is improved,and the iterative identification for the system errors based on the improved spectral clustering is ***,the comprehensive measured data of long baseline lake test and sea test show that the proposed method can accu-rately identify the system errors,and moreover can improve the positioning accuracy for the underwater target positioning.

关键词： acoustic positioning reduced parameter system error identification improved spectral clustering accuracy analy-sis

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Development and applications of the quasi‐dynamic triaxial apparatus for deep rocks

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Deep Underground Science and Engineering 2024年第1期3卷 70-90页

作者： Jinzhi Luo Yanyan Cai Jin yu Jianzhi Zhang yaoliang Zhu yao Wei School of Civil Engineering Huaqiao UniversityXiamenFujianChina Zijin School of Geology and Mining Fuzhou UniversityFuzhouChina

The mechanical behaviors of deep rocks have always posed a challenge for the implementation and safe operation of major underground engineering *** this end,this study modified the existing mainstream rock mechanics instruments equipped with a dynamic disturbance loading system and developed a second‐generation TFD‐2000/D triaxial *** first‐generation device is equipped with an independent disturbance system and an advanced EDC‐580 all‐digital servo controller,which can apply disturbing load independently,implement the function of cyclic disturbance,and combine dynamic and static *** instrument was found to be reliable for use in analyzing the damage process of rocks in the disturbance test of *** second‐generation instrument tackles three limitations of the first‐generation instrument:(i)it upgrades the strain measurement system and uses extensometers with linear variable differential transformers to accurately measure deformation;(ii)it uses the self‐balanced chamber to replace the Hoek–Franklin triaxial cell and auto‐balancing triaxial pressure chamber;and(iii)the loading rod is independently equipped with an EDC‐580 all‐digital servo controller,which measures precise *** experimental findings confirmed that the second‐generation instrument can be used for rock mechanics testing under cyclic disturbance loading,the disturbance–stress relaxation cycle,and the creep–fatigue *** this sense,the second‐generation instrument can be a useful addition to deep rock mechanical instruments and provide a valuable reference.

关键词： complex stress conditions deep rock disturbance loading modification of instrument rock mechanics

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Effect of electrical parameters and slag system on macrostructure of electroslag ingot

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China Foundry 2024年第1期21卷 44-50页

作者： Bing-jie Wang yu Wang Meng-jun Wang Lei Zhao Li-zhong Chang Xiao-fang Shi School of Metallurgy engineering Anhui University of TechnologyMa'anshan 243002AnhuiChina

To investigate the influence of electric parameters and slag system on the solidification quality of electroslag ingot during electroslag remelting,different power supply modes,current strengths and remelting slag systems were used to conduct electroslag remelting experiments on 304L austenitic stainless steel,and the macrostructure of electroslag ingots was *** results indicate that the depth of the metal pool decreases with the reduction of remelting frequency in the low frequency power supply *** effects of different power supply modes,such as low-frequency,direct current straight polarity(DCSP),and direct current reverse polarity(DCRP),on reducing the depth of the metal pool increase in that *** reducing the remelting current strength in the same power supply mode,the depth of metal pool is *** compared to the binary slag system of 70%CaF2+30%Al2O3,the ternary slag system of 60%CaF2+20%Al2O3+20%CaO is more effective in reducing the depth of the metal pool during *** the 60%CaF2+20%Al2O3+20%CaO ternary slag system results in a shallower and flatter metal pool,with columnar crystal growth occurring closer to the axial *** effect is observed for both low frequency and direct current(DC)power supply modes.

关键词： electroslag remelting frequency slag system solidification quality

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The effect of seismic action on stability of saline soil subgrade in cold region based on isothermal stratification method

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Earthquake Research Advances 2024年第3期4卷 66-81页

作者： jie Cheng yu Zhang Ying Ma Xuerui Chen Ning An School of Traffic and Transportation Lanzhou Jiaotong UniversityLanzhou730070China Key Laboratory of Railway Industry of Plateau Railway Transportation Intelligent Management and Control Lanzhou Jiaotong UniversityLanzhou730070China Gansu Institute of Engineering Geology Lanzhou730030China

With the change of seasons, the shear strength of saline soil subgrade filler will change with the change of external temperature, which will aggravate the adverse effects of seismic on the subgrade. To explore the influence of seismic action on the stability of saline soil subgrade under the influence of temperature on the strength of saline soil subgrade filler, this paper first carried out saline soil shear tests at different temperatures to obtain the influence of temperature on the shear strength of saline soil. Then, the temperature field of the saline soil subgrade was simulated, and then based on the subgrade isothermal stratification model and FLAC3D, the displacement and acceleration amplification effects of seismic action on the shady slope, sunny slope and subgrade of saline soil subgrade in different months were analyzed. The following conclusions were finally drawn: under the action of seismic, In the process of the change of subgrade temperature of Qarhan-Golmud Expressway between 7.7°C and 27°C, the change of saline soil cohesion is the main factor affecting the stability of subgrade slope, and the maximum and minimum values of subgrade surface settlement appear in September and June of each year,respectively. In August, the differences of settlement between the shady slope and the sunny slope shoulder of the subgrade were the largest, and the acceleration of the shady slope and the sunny slope and the inside of the subgrade changed most significantly in the vertical direction. Special attention should be paid to the seismic early warning in the above key months;In the range from both sides of the shoulder to the centerline of the roadbed,the acceleration amplification effect starts to increase significantly from about 3m from the centerline of the roadbed to the centerline, so it is necessary to pay attention to the seismic design of this range.

关键词： Subgrade stability Saline soils Acceleration amplification effect Seismic design

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Incorporation of source contributions to improve the accuracy of soil heavy metal mapping using small sample sizes at a county scale

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Pedosphere 2024年第1期34卷 170-180页

作者： jie SONG Xin WANG Dongsheng yu Jiangang LI Yanhe ZHAO Siwei WANG Lixia MA State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Chinese Academy of Sciences University Beijing 100049China Agricultural and Rural Bureau of Luanping County Luanping 068250China

Estimating heavy metal(HM) distribution with high precision is the key to effectively preventing Chinese medicinal plants from being polluted by the native soil. A total of 44 surface soil samples were gathered to detect the concentrations of eight HMs(As, Hg, Cu, Cr, Ni, Zn, Pb, and Cd) in the herb growing area of Luanping County, northeastern Hebei Province, China. An absolute principal component score-multiple linear regression(APCS-MLR) model was used to quantify pollution source contributions to soil HMs. Furthermore, the source contribution rates and environmental data of each sampling point were simultaneously incorporated into a stepwise linear regression model to identify the crucial indicators for predicting soil HM spatial distributions. Results showed that 88% of Cu, 72% of Cr, and 72% of Ni came from natural sources;50% of Zn, 49% of Pb, and 59% of Cd were mainly caused by agricultural activities;and 44% of As and 56% of Hg originated from industrial activities. When three-type(natural, agricultural, and industrial) source contribution rates and environmental data were simultaneously incorporated into the stepwise linear regression model, the fitting accuracy was significantly improved and the model could explain 31%–86% of the total variance in soil HM concentrations. This study introduced three-type source contributions of each sampling point based on APCS-MLR analysis as new covariates to improve soil HM estimation precision, thus providing a new approach for predicting the spatial distribution of HMs using small sample sizes at the county scale.

关键词： absolute principal component score-multiple linear regression Chinese herbal medicine influencing factors spatial distribution stepwise multiple regression

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Mapping soil organic matter in cultivated land based on multi-year composite images on monthly time scales

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Journal of Integrative Agriculture 2024年第4期23卷 1393-1408页

作者： jie Song Dongsheng yu Siwei Wang Yanhe Zhao Xin Wang Lixia Ma Jiangang Li State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Agricultural and Rural Bureau of Luanping County Luanping 068250China Chinese Academy of Sciences University Beijing 100049China

Rapid and accurate acquisition of soil organic matter(SOM)information in cultivated land is important for sustainable agricultural development and carbon balance *** study proposed a novel approach to predict SOM with high accuracy using multiyear synthetic remote sensing variables on a monthly *** obtained 12 monthly synthetic Sentinel-2 images covering the study area from 2016 to 2021 through the Google Earth Engine(GEE)platform,and reflectance bands and vegetation indices were extracted from these composite *** the random forest(RF),support vector machine(SVM)and gradient boosting regression tree(GBRT)models were tested to investigate the difference in SOM prediction accuracy under different combinations of monthly synthetic *** showed that firstly,all monthly synthetic spectral bands of Sentinel-2 showed a significant correlation with SOM(P<0.05)for the months of January,March,April,October,and ***,in terms of single-monthly composite variables,the prediction accuracy was relatively poor,with the highest R^(2)value of 0.36 being observed in *** monthly synthetic environmental variables were grouped in accordance with the four quarters of the year,the first quarter and the fourth quarter showed good performance,and any combination of three quarters was similar in estimation *** overall best performance was observed when all monthly synthetic variables were incorporated into the ***,among the three models compared,the RF model was consistently more accurate than the SVM and GBRT models,achieving an R^(2)value of *** for band 12 in December,the importance of the remaining bands did not exhibit significant *** research offers a new attempt to map SOM with high accuracy and fine spatial resolution based on monthly synthetic Sentinel-2 images.

关键词： soil organic matter Sentinel-2 monthly synthetic images machine learning model spatial prediction

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