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Characteristics of orthorhombic anisotropic seismic response induced by horizontal in situ stress in vertical transversely isotropic media

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Science China Earth Sciences 2024年第7期67卷 2291-2310页

作者： Xinpeng pan Chengxu LU Zhizhe ZHAO Jianxin LIU School of Geoscience and Info-Physics Central South UniversityChangsha 410083China Hunan Key Labraory of Nonferrous resources and Geological Disaster Exploration Central South University Changsha 410083China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University) Ministry of EducationChangsha 410083China PowerChina Zhongnan Engineering Corporation Limited Changsha 410014China

Sedimentary strata typically exhibit the characteristics of transverse isotropy(VTI)with a vertical axis of ***,fractures in sedimentary strata tend to produce anisotropic closure due to horizontal in situ stress,resulting in pronounced orthorhombic anisotropy in VTI media under such stress conditions and influencing the propagation behavior of seismic *** studies have primarily focused on the elastic wave velocity anisotropy induced by applied stress in isotropic background media,neglecting the impact of VTI background media on the anisotropy induced by horizontal in situ stress and the response characteristics of seismic wave *** address these gaps,we first establish the effective elastic stiffness tensor of VTI media under horizontal in situ stress using nonlinear acoustoelastic ***,we derive the accurate and linearized approximate equations for P-wave seismic reflectivity of VTI media under horizontal in situ stress,based on wave equations and scattering theory,***,we compare and analyze the characteristics of orthorhombic anisotropic seismic response induced by horizontal in situ stress at various types of elastic reflection *** results demonstrate that the linearized approximation of the seismic reflection response characteristics closely aligns with the accurate equations under conditions of small stress below 10 MPa,effectively capturing the azimuth-dependent orthorhombic anisotropy induced by horizontal in situ stress in VTI *** results of this study also provide a novel theoretical approach and valuable insights into the seismic prediction of in situ stress.

关键词： Horizontal in situ stress Nonlinear acoustoelastic theory Linear slip theory Orthorhombic anisotropy Stress seismic prediction

Mechanisms of liver injuries caused by traditional Chinese medicines

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Hepatobiliary & pancreatic Diseases International 2024年第3期23卷 310-312页

作者： Shui-Fang Jin Qi pan Jin-Peng Zhou Xiao-Ping pan Intensive Care Unit The First Affiliated Hospital of Zhejiang Chinese Medical University(Zhejiang Provincial Hospital of Chinese Medicine)Hangzhou 310006China Institute of Liver Diseases College of Basic Medical SciencesZhejiang Chinese Medical UniversityHangzhou 310053China The Second Clinical Medical College of Zhejiang Chinese Medical University Hangzhou 310056China

Drug-induced liver injury(DILI)is a common adverse drug reaction,which can even result in liver failure[1,2].The Chinese Medical Association issued the Guidelines for the Diagnosis and Treatment of DILI based on the roussel Uclaf Causality Assessment Method(rUCAM)in 2015[3].A previous study reported that traditional Chinese medicines(TCMs),herbal and dietary supplements,and antituberculosis drugs were the main causes of DILI in China[4].Herb-induced liver injury(HILI)refers to liver injury caused by TCMs,natural drugs,and their related preparations[5].

关键词： drugs tuberculosis TCM

An ensemble and cost-sensitive learning-based root cause diagnosis scheme for wireless networks with spatially imbalanced user data distribution

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Science China(Information Sciences) 2024年第7期67卷 331-332页

作者： Qi WANG Zhiwen pan Nan LIU National Mobile Communications research Laboratory Southeast University Purple Mountain Laboratories

root cause diagnosis, a key component of self-healing, plays a vital role in fault management. The spatially imbalanced network key performance indicators (KPIs) reported by users increase the difficulty of identifying root *** [1,2], the image inpainting technique is inspired to address issues caused by sparse reports across the coverage area.

关键词： Wireless networks

Achieving high strength and rapid degradation in Mg-Gd-Ni alloys by regulating LPSO phase morphology combined with extrusion

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Journal of Magnesium and Alloys 2024年第6期12卷 2312-2326页

作者： Kai Ma Jingfeng Wang Yinhong Peng Chaoneng Dai Yuanlang pan Ye Wang Danqian Wang Jinxing Wang Yanlong Ma Fusheng pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044PR China National Engineering research Center for Magnesium Alloys Chongqing 400044PR China College of Chemistry and Chemical Engineering Chongqing UniversityChongqing 401331PR China College of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054PR China

In this study,Mg-13.2Gd-4.3Ni alloys containing continuous bulk-shaped long-period stacking ordered(LPSO),lamellar LPSO,and a small amount of eutectic phase were prepared,and the evolution of microstructure at different extrusion temperatures and its influence on mechanical and degradation properties as well as corrosion mechanism were *** before extrusion can effectively promote the precipitation of lamellar LPSO in ***400 with higher volume fraction of non-DrXed grains exhibited higher strength,which was mainly due to strong texture,high dislocation density,and high volume fraction of lamellar *** EX420 with higher volume fraction of DrXed grains showed higher degradation rate,which was mainly due to the higher density of grain *** EX400 exhibited excellent comprehensive properties with tensile yield strength(TYS)of 334 MPa,ultimate tensile strength(UTS)of 484 MPa and elongation(EL)of 7.4%,ultimate compressive strength(UCS)of 638 MPa and compressive yield strength(CYS)of 443 MPa,degradation rate of 86.1 mg/cm^(2)/h at 93℃in 3 wt.%KCl solution.

关键词： Mg-Gd-Ni alloys LPSO Mechanical properties Degradation rate

Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum

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Journal of Mountain Science 2024年第2期21卷 484-499页

作者： pan Sipei LIANG Jiale CHEN Wanxu PENG Yelin College of Land Management Nanjing Agricultural UniversityNanjing 210095China National&Local Joint Engineering research Center for rural Land resources Use and Consolidation Nanjing 210095China Jiangsu Provincial Key Laboratory of Geographic Information Technology School of Geography and Ocean ScienceNanjing UniversityNanjing 210023China Key Laboratory of Natural resources Monitoring and Supervision in Southern Hilly region Ministry of Natural ResourcesChangsha 410118China Yunnan Key Laboratory of Plateau Geographic Processes and Environmental Changes Faculty of GeographyYunnan Normal UniversityKunming 650500China Hubei Key Laboratory of regional Ecology and Environmental Change School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China

The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food *** spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic ***,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains *** address the gap,in virtue of spatial analysis and geographically weighted regression(GWr)model,the cropland use change in the Yangtze river Basin(YrB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope *** showed that the slope spectrum curves of cropland area-frequency in the YrB showed a first upward then a downward *** change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution *** analysis of morphological parameters of cropland slope spectrum revealed that the further down the YrB,the stronger the flattening characteristics,the more obvious the *** province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was *** most common cropland use change type in the YrB was horizontal expansion *** factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study *** research is of practical significance for the rational utilization of cropland at the watershed scale.

关键词： Cropland climbing Land use change Slope spectrum Driving factors Geographically weighted regression Yangtze river Basin

Shear strength degradation of gas hydrate-bearing sediment due to partial hydrate dissociation

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Journal of rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2749-2763页

作者： Yuan Zhou Jiazuo Zhou pan Chen Changfu Wei State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China China University of Geosciences Wuhan430074China

Extraction of methane hydrate from subseafloor reservoir may potentially trigger seabed slides and induce *** address the problems,it is crucial to properly characterize the phase equilibrium condition of pore hydrate and the shear strength of the *** one of the key constitutive components,the phase equilibrium condition enforces a constraint over pore gas pressure,temperature and unhydrated water *** a constraint,however,has been traditionally ignored in analyzing the mechanical behavior of hydrate-bearing *** this paper,a series of stepwise hydrate dissociation tests was performed,and the phase equilibrium condition of pore hydrate was determined,providing an effective way to evaluate the unhydrated water content during hydrate ***,a series of direct shear tests was also conducted to explore the shear strength characteristics of the *** is shown that the shear strength of the hydrate-bearing soil can be significantly influenced by pore gas pressure,unhydrated water content,hydrate saturation and several other *** particular,the measured shear strength depends upon the initial water content of the sample,pointing to a potential problem that the shear strength could be wrongly determined if not properly interpreted.A shear strength criterion,which enforces the equilibrium condition of pore hydrate,is developed for hydrate-bearing soil,establishing a link between the equilibrium condition and the shear *** proposed equation describes well the shear strength characteristics of hydrate-bearing soils,remarkably unifying the effects of pore pressure,temperature,water content and hydrate saturation.

关键词： Hydrate-bearing soil Phase equilibrium condition Shear strength Unhydrated water content Mechanical behavior

Scenario Modeling-Aided AP Placement Optimization Method for Indoor Localization and Network Access

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China Communications 2024年第3期21卷 37-50页

作者： pan Hao Chen Yu Qi Xiaogang Liu Meili School of Mathematics and Statistics Xidian UniversityXi’an 710126China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China School of Software Nanchang Hangkong UniversityNanchang 330063China

Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures,received signal strength(rSS)-based indoor localization systems have received much *** placement of access points(APs)significantly influences localization accuracy and network ***,the indoor scenario and network access are not fully considered in previous AP placement optimization *** study proposes a practical scenario modelingaided AP placement optimization method for improving localization accuracy and network *** order to reduce the gap between simulation-based and field measurement-based AP placement optimization methods,we introduce an indoor scenario modeling and Gaussian process-based rSS prediction *** that,the localization and network access metrics are implemented in the multiple objective particle swarm optimization(MOPSO)solution,Pareto front criterion and virtual repulsion force are applied to determine the optimal AP ***,field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and rSS prediction model.A thorough comparison confirms the localization and network access improvement attributed to the proposed anchor placement method.

关键词： indoor localization MOPSO network access rSS prediction

Coalbursts in China: Theory, practice and management

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Journal of rock Mechanics and Geotechnical Engineering 2024年第1期16卷 1-25页

作者： Yishan pan Yimin Song Hao Luo Yonghui Xiao Institute of Disaster rock Mechanics Liaoning UniversityShenyang110036China School of Civil Engineering North China University of TechnologyBeijing100144China College of Computer Science Liaoning UniversityShenyang110036China School of Physics Liaoning UniversityShenyang110036China

Coalburst is one of the most serious disasters that threaten the safe production of coal mines, and this disaster is particularly serious in China. This paper presents an overview of coalbursts in China since 1980s. From the "stress and energy" and "regional and local" perspectives, the achievements in the theory, practice and management of coalbursts in China are systematically summarized. A theoretical system of coalbursts has been formed to reveal the deformational behavior of coalbursts and explain the mechanism of coalbursts. The occurrence conditions of coalbursts are put forward and the critical stress is obtained. The stress index method for risk evaluation of coalbursts before mining is proposed, and the deformation localization prediction method of coalbursts is put forward. The relationship between energy release and absorption in the process of coalbursts is found, and the prevention and control methods of coalbursts, including the regional method, the local method and support, are presented. The safety evaluation index of coalburst prevention and control is put forward. The integrated prevention and control method for coal and gas outbursts is proposed. The prevention and control technology and equipment of coalbursts have also been developed. Amongst them, the distribution law of the critical stress in China coalburst mines is discovered. The technology and equipment for monitoring, prevention and control of coalbursts, as well as for integrated prevention and control of combined coalbursts and other disasters, have been developed. The energy-absorbing and coalburst-preventing support technology for roadways is invented, and key engineering parameters of coalburst prevention and control are pointed out. In China, coalburst prevention and control laws and standards have been developed. Technical standards for coalbursts are formulated, statute and regulations for coal mines are established, and regulatory documents are promoted.

关键词： Coalbursts rockbursts Dynamic disaster Energy-absorbing support Monitoring and early warning

Promotion effects of salt-alkali on ammonia volatilization in a coastal soil

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Pedosphere 2024年第1期34卷 191-199页

作者： Zhenqi SHI Dongli SHE Yongchun pan Yongqiu XIA College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China Jiangsu Province Engineering research Center for Agricultural Soil-Water Efficient Utilization Carbon Sequestration and Emission ReductionNanjing 210098China Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Coastal ecosystems are highly susceptible to salt-related problems due to their formation process and geographical location. As such ecosystems are the most accessible land resources on Earth, clarifying and quantifying the effects of salt-alkali conditions on N concentration and ammonia(NH_(3)) volatilization are pivotal for promoting coastal agricultural productivity. The challenge in establishing this effect is to determine how salt-alkali conditions impact NH_(3) volatilization through direct or indirect interactions. An incubation experiment using a coastal soil from a paddy farmland, combined with the structural equation modeling(SEM) method, was conducted to reveal the net effects of salt-alkali on NH_(3) volatilization and the role of environmental and microbial factors in mutual interaction networks. The specific experimental design consisted of four salt treatments(S1, S2, S3, and S4: 1‰, 3‰, 8‰, and 15‰ NaCl by mass of soil, respectively), four alkaline treatments(A1, A2, A3, and A4: 0.5‰, 1‰, 3‰, and 8‰ NaHCO_(3)by mass of soil, respectively) and a control without NaCl or NaHCO_(3) addition(CK), and each treatment had three urea concentrations(N1, N2, and N3: 0.05, 0.10, and 0.15 g N kg^(-1) soil,respectively) and three replicates. At the N1, N2, and N3 levels, NH_(3)volatilization increased by 9.31%–34.98%, 3.07%–26.92%, and 2.99%–43.61% as the NaCl concentration increased from 1‰ to 15‰, respectively, compared with CK. With an increase in the NaHCO_(3)concentration from 0.5‰ to 8‰, NH_(3) volatilization increased by 8.36%–56.46%, 5.49%–30.10%, and 30.72%–73.18% at the N1, N2, and N3 levels, respectively, compared with CK. According to the SEM method, salinity and alkalinity had positive direct effects on NH_(3)volatilization, with standardized path coefficients of 0.40 and 0.19, *** the total effects(net positive and negative effects) in the SEM results, alkalinity had a greater influence than salinity(total standardized coefficien

关键词： alkalinity coastal ecosystem NH_(3)emission N-transforming microbe salinity structural equation modeling