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A novel mitigation measure for normal fault-induced deformations on pile-raft systems
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作者 Mohammadreza Jahanshahi Nowkandeh Mehdi Ashtiani 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第1期15-33,共19页
Evidence from recent earthquakes has shown destructive consequences of fault-induced permanent ground movement on structures.Such observations have increased the demand for improvements in the design of structures tha... Evidence from recent earthquakes has shown destructive consequences of fault-induced permanent ground movement on structures.Such observations have increased the demand for improvements in the design of structures that are dramatically vulnerable to surface fault ruptures.In this study a novel connection between the raft and the piles is proposed to mitigate the hazards associated with a normal fault on pile-raft systems by means of 3D finite element(FE)modeling.Before embarking on the parametric study,the strain-softening constitutive law used for numerical modeling of the sand has been validated against centrifuge test results.The exact location of the fix-head and unconnected pile-raft systems relative to the outcropping fault rupture in the free-field is parametrically investigated,revealing different failure mechanisms.The performance of the proposed connection for protecting the pile-raft system against normal fault-induced deformations is assessed by comparing the geotechnical and structural responses of both types of foundation.The results indicate that the pocket connection can relatively reduce the cap rotation and horizontal and vertical displacements of the raft in most scenarios.The proposed connection decreases the bending moment response of the piles to their bending moment capacity,verging on a fault offset of 0.6 m at bedrock. 展开更多
关键词 normal fault rupture failure mechanism pile-raft system pocket connection finite element modeling
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Depth-Guided Vision Transformer With Normalizing Flows for Monocular 3D Object Detection
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作者 Cong Pan Junran Peng Zhaoxiang Zhang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期673-689,共17页
Monocular 3D object detection is challenging due to the lack of accurate depth information.Some methods estimate the pixel-wise depth maps from off-the-shelf depth estimators and then use them as an additional input t... Monocular 3D object detection is challenging due to the lack of accurate depth information.Some methods estimate the pixel-wise depth maps from off-the-shelf depth estimators and then use them as an additional input to augment the RGB images.Depth-based methods attempt to convert estimated depth maps to pseudo-LiDAR and then use LiDAR-based object detectors or focus on the perspective of image and depth fusion learning.However,they demonstrate limited performance and efficiency as a result of depth inaccuracy and complex fusion mode with convolutions.Different from these approaches,our proposed depth-guided vision transformer with a normalizing flows(NF-DVT)network uses normalizing flows to build priors in depth maps to achieve more accurate depth information.Then we develop a novel Swin-Transformer-based backbone with a fusion module to process RGB image patches and depth map patches with two separate branches and fuse them using cross-attention to exchange information with each other.Furthermore,with the help of pixel-wise relative depth values in depth maps,we develop new relative position embeddings in the cross-attention mechanism to capture more accurate sequence ordering of input tokens.Our method is the first Swin-Transformer-based backbone architecture for monocular 3D object detection.The experimental results on the KITTI and the challenging Waymo Open datasets show the effectiveness of our proposed method and superior performance over previous counterparts. 展开更多
关键词 Monocular 3D object detection normalizing flows Swin Transformer
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Neuroimaging in atypical normal tension glaucoma:debating routine implementation in the absence of classic neurological findings
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作者 Umay Güvenç Gülizar Demirok +1 位作者 Güner Üney Selma Uzman 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第3期509-517,共9页
●AIM:To assess the necessity of neuroimaging in patients with neurological or atypical findings of normal tension glaucoma(NTG)who do not exhibit typical glaucoma manifestations.●METHODS:A retrospective analysis was... ●AIM:To assess the necessity of neuroimaging in patients with neurological or atypical findings of normal tension glaucoma(NTG)who do not exhibit typical glaucoma manifestations.●METHODS:A retrospective analysis was conducted on 90 atypical NTG patients who underwent cranial magnetic resonance imaging(MRI)due to atypical symptoms.The demographic characteristics,clinical parameters,and radiological findings were recorded.●RESULTS:Among the patients,66.7%had abnormal radiology results,with the most common findings being gliosis(34.4%),sequelae of cerebrovascular events and vascular malformations(14.4%),and benign intracranial mass lesions(11%).Non-glaucomatous visual field defects were more frequently observed in patients with abnormal neuroimaging results.However,there were no significant differences in intraocular pressure,optic disc parameters,retinal nerve fiber layer thickness,and visual field indices between patients with normal and abnormal radiological results.The mean age of the patients was 58.74y.Interestingly,there was a significant age difference,with the abnormal radiology group having a higher median age(P=0.021).●CONCLUSION:The study highlights the importance of cranial imaging in older NTG patients to detect underlying pathologies and prevent misdiagnosis.It suggests that neuroimaging may be warranted in NTG patients with atypical visual field defects incompatible with glaucoma.However,routine neuroimaging in all NTG patients without classic neurological signs may not be necessary. 展开更多
关键词 normal tension glaucoma NEUROIMAGING atypical visual field defects
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A Normalizing Flow-Based Bidirectional Mapping Residual Network for Unsupervised Defect Detection
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作者 Lanyao Zhang Shichao Kan +3 位作者 Yigang Cen Xiaoling Chen Linna Zhang Yansen Huang 《Computers, Materials & Continua》 SCIE EI 2024年第2期1631-1648,共18页
Unsupervised methods based on density representation have shown their abilities in anomaly detection,but detection performance still needs to be improved.Specifically,approaches using normalizing flows can accurately ... Unsupervised methods based on density representation have shown their abilities in anomaly detection,but detection performance still needs to be improved.Specifically,approaches using normalizing flows can accurately evaluate sample distributions,mapping normal features to the normal distribution and anomalous features outside it.Consequently,this paper proposes a Normalizing Flow-based Bidirectional Mapping Residual Network(NF-BMR).It utilizes pre-trained Convolutional Neural Networks(CNN)and normalizing flows to construct discriminative source and target domain feature spaces.Additionally,to better learn feature information in both domain spaces,we propose the Bidirectional Mapping Residual Network(BMR),which maps sample features to these two spaces for anomaly detection.The two detection spaces effectively complement each other’s deficiencies and provide a comprehensive feature evaluation from two perspectives,which leads to the improvement of detection performance.Comparative experimental results on the MVTec AD and DAGM datasets against the Bidirectional Pre-trained Feature Mapping Network(B-PFM)and other state-of-the-art methods demonstrate that the proposed approach achieves superior performance.On the MVTec AD dataset,NF-BMR achieves an average AUROC of 98.7%for all 15 categories.Especially,it achieves 100%optimal detection performance in five categories.On the DAGM dataset,the average AUROC across ten categories is 98.7%,which is very close to supervised methods. 展开更多
关键词 Anomaly detection normalizing flow source domain feature space target domain feature space bidirectional mapping residual network
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Unveiling the silent link:Normal-tension glaucoma's enigmatic bond with cardiac blood flow
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作者 Prasanna Venkatesh Ramesh Arvind Kumar Morya +5 位作者 Ajanya K Aradhya Pavithra Pannerselvam Sai Thaejesvi Gopalakrishnan Shruthy Vaishali Ramesh Aji Kunnath Devadas Navaneeth Krishna 《World Journal of Cardiology》 2024年第1期10-15,共6页
This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma(NTG),a condition that continues to baffle clinicians and researchers alike.NTG,ch... This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma(NTG),a condition that continues to baffle clinicians and researchers alike.NTG,characterized by optic nerve damage and visual field loss despite normal intraocular pressure,has long puzzled clinicians.One emerging perspective suggests that alterations in ocular blood flow,particularly within the optic nerve head,may play a pivotal role in its pathogenesis.While NTG shares commonalities with its high-tension counterpart,its unique pathogenesis and potential ties to cardiovascular health make it a fascinating subject of exploration.It navigates through the complex web of vascular dysregulation,blood pressure and perfusion pressure,neurovascular coupling,and oxidative stress,seeking to uncover the hidden threads that tie the heart and eyes together in NTG.This review explores into the intricate mechanisms connecting cardiovascular factors to NTG,shedding light on how cardiac dynamics can influence ocular health,particularly in cases where intraocular pressure remains within the normal range.NTG's enigmatic nature,often characterized by seemingly contradictory risk factors and clinical profiles,underscores the need for a holistic approach to patient care.Drawing parallels to cardiac health,we examine into the shared vascular terrain connecting the heart and the eyes.Cardiovascular factors,including systemic blood flow,endothelial dysfunction,and microcirculatory anomalies,may exert a profound influence on ocular perfusion,impacting the delicate balance within the optic nerve head.By elucidating the subtle clues and potential associations between cardiology and NTG,this review invites clinicians to consider a broader perspective in their evaluation and management of this elusive condition.As the understanding of these connections evolves,so too may the prospects for early diagnosis and tailored interventions,ultimately enhancing the quality of life for those living with NTG. 展开更多
关键词 normal tension glaucoma Vascular dysregulation Ocular blood flow Blood pressure Perfusion pressure Oxidative stress
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Assessment of vegetation cover changes and the contributing factors in the Al-Ahsa Oasis using Normalized Difference Vegetation Index(NDVI)
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作者 Walid CHOUARI 《Regional Sustainability》 2024年第1期42-53,共12页
The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influ... The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influenced by both expansion and degradation factors.Therefore,it is important to study the spatiotemporal variation of vegetation cover for the sustainable management of oasis resources.This study used Landsat satellite images in 1987,2002,and 2021 to monitor the spatiotemporal variation of vegetation cover in the Al-Ahsa Oasis,applied multi-temporal Normalized Difference Vegetation Index(NDVI)data spanning from 1987 to 2021 to assess environmental and spatiotemporal variations that have occurred in the Al-Ahsa Oasis,and investigated the factors influencing these variation.This study reveals that there is a significant improvement in the ecological environment of the oasis during 1987–2021,with increase of NDVI values being higher than 0.10.In 2021,the highest NDVI value is generally above 0.70,while the lowest value remains largely unchanged.However,there is a remarkable increase in NDVI values between 0.20 and 0.30.The area of low NDVI values(0.00–0.20)has remained almost stable,but the region with high NDVI values(above 0.70)expands during 1987–2021.Furthermore,this study finds that in 1987–2002,the increase of vegetation cover is most notable in the northern region of the study area,whereas from 2002 to 2021,the increase of vegetation cover is mainly concentrated in the northern and southern regions of the study area.From 1987 to 2021,NDVI values exhibit the most pronounced variation,with a significant increase in the“green”zone(characterized by NDVI values exceeding 0.40),indicating a substantial enhancement in the ecological environment of the oasis.The NDVI classification is validated through 50 ground validation points in the study area,demonstrating a mean accuracy of 92.00%in the detection of vegetation cover.In general,both the user’s and producer’s accuracies of NDVI classification are extremely high in 1987,2002,and 2021.Finally,this study suggests that environmental authorities should strengthen their overall forestry project arrangements to combat sand encroachment and enhance the ecological environment of the Al-Ahsa Oasis. 展开更多
关键词 normalized Difference Vegetation Index(NDVI) Vegetation cover Ecological environment Land use and land cover(LULC) Urban expansion Al-Ahsa Oasis
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Shear sliding of rough-walled fracture surfaces under unloading normal stress
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作者 Qian Yin Chun Zhu +5 位作者 Jiangyu Wu Hai Pu Qi Wang Yuanchao Zhang Hongwen Jing Tianci Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2658-2675,共18页
Through high-precision engraving,self-affine sandstone joint surfaces with various joint roughness coefficients(JRC=3.21e12.16)were replicated and the shear sliding tests under unloading normal stress were conducted r... Through high-precision engraving,self-affine sandstone joint surfaces with various joint roughness coefficients(JRC=3.21e12.16)were replicated and the shear sliding tests under unloading normal stress were conducted regarding various initial normal stresses(1e7 MPa)and numbers of shearing cycles(1 e5).The peak shear stress of fractures decreased with shear cycles due to progressively smooth surface morphologies,while increased with both JRC and initial normal stress and could be verified using the nonlinear Barton-Bandis failure criterion.The joint friction angle of fractures exponentially increased by 62.22%e64.87%with JRC while decreased by 22.1%e24.85%with shearing cycles.After unloading normal stress,the sliding initiation time of fractures increased with both JRC and initial normal stress due to more tortuous fracture morphologies and enhanced shearing resistance capacity.The surface resistance index(SRI)of fractures decreased by 4.35%e32.02%with increasing shearing cycles due to a more significant reduction of sliding initiation shear stress than that for sliding initiation normal stress,but increased by a factor of 0.41e1.64 with JRC.After sliding initiation,the shear displacement of fractures showed an increase in power function.By defining a sliding rate threshold of 5105 m/s,transition from“quasi-static”to“dynamic”sliding of fractures was identified,and the increase of sliding acceleration steepened with JRC while slowed down with shearing cycles.The normal displacement experienced a slight increase before shear sliding due to deformation recovery as the unloading stress was unloaded,and then enhanced shear dilation after sliding initiation due to climbing effects of surface asperities.Dilation was positively related to the shear sliding velocity of fractures.Wear characteristics of the fracture surfaces after shearing failure were evaluated using binary calculation,indicating an increasing shear area ratio by 45.24%e91.02%with normal stress. 展开更多
关键词 Unloading normal stress Rough fracture surface Shear sliding normal displacement Shear wear characteristics
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Analysis of College Students’ Test Scores Based on Two-Component Mixed Generalized Normal Distribution
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作者 Luliang Wen Haiwu Rong Yanjun Qiu 《Journal of Data Analysis and Information Processing》 2023年第1期69-80,共12页
In order to improve the fitting accuracy of college students’ test scores, this paper proposes two-component mixed generalized normal distribution, uses maximum likelihood estimation method and Expectation Conditiona... In order to improve the fitting accuracy of college students’ test scores, this paper proposes two-component mixed generalized normal distribution, uses maximum likelihood estimation method and Expectation Conditional Maxinnization (ECM) algorithm to estimate parameters and conduct numerical simulation, and performs fitting analysis on the test scores of Linear Algebra and Advanced Mathematics of F University. The empirical results show that the two-component mixed generalized normal distribution is better than the commonly used two-component mixed normal distribution in fitting college students’ test data, and has good application value. 展开更多
关键词 Two-Component Mixed Generalized normal Distribution Two-Component Mixed normal Distribution ECM Algorithm Test Scores
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地震勘探专业名词“Normal Moveout”的中文翻译刍议
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作者 安勇 《内江科技》 2023年第9期33-34,54,共3页
英文专有名词的翻译具有极强的专业性和特殊性,是深入学习和理解国外专业理论的基础。Nomal Moveout作为地震勘探中一个非常重要的专有名词,笔者认为,其常用的中文翻译“正常时差”是否妥当,值得商榷。本文首先阐述了Normal Moveout在... 英文专有名词的翻译具有极强的专业性和特殊性,是深入学习和理解国外专业理论的基础。Nomal Moveout作为地震勘探中一个非常重要的专有名词,笔者认为,其常用的中文翻译“正常时差”是否妥当,值得商榷。本文首先阐述了Normal Moveout在地震勘探的物理意义,然后分析了基础英文词汇的中文释义,根据两者的关联性,认为将Normal Moveout翻译为“垂直时差”或“法线时差”更为合理、精准,具有专业性。 展开更多
关键词 地震勘探 正常时差 专业名词 英文词汇 专有名词 中文翻译 normal 专业性
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Regulatory mechanisms of retinal ganglion cell death in normal tension glaucoma and potential therapies 被引量:2
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作者 Wen-Cui Shen Bing-Qing Huang Jin Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第1期87-93,共7页
Normal tension glaucoma(NTG)is a multifactorial optic neuropathy characterized by normal intraocular pressure,progressive retinal ganglion cell(RGC)death,and glaucomatous visual field loss.Recent studies have describe... Normal tension glaucoma(NTG)is a multifactorial optic neuropathy characterized by normal intraocular pressure,progressive retinal ganglion cell(RGC)death,and glaucomatous visual field loss.Recent studies have described the mechanisms underlying the pathogenesis of NTG.In addition to controlling intraocular pressure,neuroprotection and reduction of RGC degeneration may be beneficial therapies for NTG.In this review,we summarized the main regulatory mechanisms of RGC death in NTG,including autophagy,glutamate neurotoxicity,oxidative stress,neuroinflammation,immunity,and vasoconstriction.Autophagy can be induced by retinal hypoxia and axonal damage.In this process,ischemia can cause mutations of optineurin and activate the nuclear factor-kappa B pathway.Glutamate neurotoxicity is induced by the over-stimulation of N-methyl-D-aspartate membrane receptors by glutamate,which occurs in RGCs and induces progressive glaucomatous optic neuropathy.Oxidative stress also participates in NTG-related glaucomatous optic neuropathy.It impairs the mitochondrial and DNA function of RGCs through the apoptosis signal-regulating kinase-JUN N-terminal kinase pathway.Moreover,it increases inflammation and the immune response of RGCs.Endothelin 1 causes endothelial dysfunction and impairment of ocular blood flow,promoting vasospasm and glaucomatous optic neuropathy,as a result of NTG.In conclusion,we discussed research progress on potential options for the protection of RGCs,including TANK binding kinase 1 inhibitors regulating autophagy,N-methyl-D-aspartate receptor antagonists inhibiting glutamate toxicity,ASK1 inhibitors regulating mitochondrial function,and antioxidants inhibiting oxidative stress.In NTG,RGC death is regulated by a network of mechanisms,while various potential targets protect RGCs.Collectively,these findings provide insight into the pathogenesis of NTG and potential therapeutic strategies. 展开更多
关键词 AUTOPHAGY endothelin 1 glutamate neurotoxicity inhibitor nerve regeneration NEUROINFLAMMATION normal tension glaucoma oxidative stress retinal ganglion cell VASOCONSTRICTION
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OpenNAU:An open-source platform for normalizing,analyzing,and visualizing cancer untargeted metabolomics data 被引量:1
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作者 Qingrong Sun Qingqing Xu +3 位作者 Majie Wang Yongcheng Wang Dandan Zhang Maode Lai 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2023年第5期550-562,共13页
Objective:As an important part of metabolomics analysis,untargeted metabolomics has become a powerful tool in the study of tumor mechanisms and the discovery of metabolic markers with high-throughput spectrometric dat... Objective:As an important part of metabolomics analysis,untargeted metabolomics has become a powerful tool in the study of tumor mechanisms and the discovery of metabolic markers with high-throughput spectrometric data which also poses great challenges to data analysis,from the extraction of raw data to the identification of differential metabolites.To date,a large number of analytical tools and processes have been developed and constructed to serve untargeted metabolomics research.The different selection of analytical tools and parameter settings lead to varied results of untargeted metabolomics data.Our goal is to establish an easily operated platform and obtain a repeatable analysis result.Methods:We used the R language basic environment to construct the preprocessing system of the original data and the LAMP(Linux+Apache+MySQL+PHP)architecture to build a cloud mass spectrum data analysis system.Results:An open-source analysis software for untargeted metabolomics data(openNAU)was constructed.It includes the extraction of raw mass data and quality control for the identification of differential metabolic ion peaks.A reference metabolomics database based on public databases was also constructed.Conclusions:A complete analysis system platform for untargeted metabolomics was established.This platform provides a complete template interface for the addition and updating of the analysis process,so we can finish complex analyses of untargeted metabolomics with simple human-computer interactions.The source code can be downloaded from https://github.com/zjuRong/openNAU. 展开更多
关键词 Untargeted metabolomics LAMP architecture shiny normalIZATION reference metabolomics
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1991-2020 climate normal in the European Alps:focus on high-elevation environments 被引量:1
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作者 NIGRELLI Guido CHIARLE Marta 《Journal of Mountain Science》 SCIE CSCD 2023年第8期2149-2163,共15页
Alps are an important geographical area of the European continent and,in this area,temperature increase is most evident.However,the 1991-2020 climate normal in the Alps has still not been thoroughly investigated.Aimin... Alps are an important geographical area of the European continent and,in this area,temperature increase is most evident.However,the 1991-2020 climate normal in the Alps has still not been thoroughly investigated.Aiming to fill this gap with a focus on high-elevation environments,minimum and maximum daily air temperature acquired by 23 automatic weather station were used.The results show that the mean annual values of minimum and maximum temperature for the 1991-2020 climate normal in the Alps are-2.4℃ and 4.4℃,respectively,with a warming rate of 0.5℃/10 years.The mean annual temperature comparison between 1961-1990 and 1971-2000,1961-1990 and 1981-2010,1961-1990 and 1991-2020 climate normal show an increase of 0.3℃,0.5℃ and 0.9℃,respectively.The results also confirm that seasonal and annual temperatures are rising through the whole Alpine arc,mainly in summer and autumn.This work highlights that annual minimum and maximum temperature do not seem to be affected by a positive elevation-dependent warming.Instead,a positive elevation-dependent warming in the maximum values of the annual minimum temperature was found.If anthropogenic emissions maintain the trend of the last decades,the expected mean annual temperature of the 2001-2030 climate normal is-0.2℃,with an increase of 0.5℃ if compared to the 1991-2020 climate normal and with an increase of 1.5℃ if compared to the 1961-1990 climate normal.This study highlights the warming rate that is now present in the European Alps,provides indications on the warming rate that will occur in the coming years and highlights the importance of carrying out investigations that consider not only the last 30-year climate normal,but also the most recent 30-year climate normal by comparing them with each other. 展开更多
关键词 Air temperature trend Climate normal Climate change High mountain climate ALPS
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Frictional behavior of quartz gouge during slide-hold-slide considering normal stress oscillation 被引量:1
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作者 Kang Tao Wengang Dang 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第3期108-121,共14页
Slide-hold-slide(SHS)test is an essential experimental approach for studying the frictional stability of faults.The origin SHS framework was established based on a consistent constant normal stress,which cannot truly ... Slide-hold-slide(SHS)test is an essential experimental approach for studying the frictional stability of faults.The origin SHS framework was established based on a consistent constant normal stress,which cannot truly reflect the stress disturbance around fault zones.In this paper,we conducted a series of'dynamic SHS tests',which includes normal stress oscillations in the relaxation stage with different oscillation amplitudes and frequencies on synthetic quartz gouge using a double direct shear assembly.The experimental results reveal that the amplitude of the normal load oscillation has a remarkable effect on the frictional relaxation and healing patterns.However,the frequency of the normal load oscillation has a minor effect.Additionally,the shear loading rate is proportional to the normal loading rate during the relaxation stage,and the normal stiffness of the quartz layer remains nearly constant under various loading conditions.The creep rate during the hold phase is not obviously affected by the normal load oscillation,while the precursory slip is also sensitive to the oscillation amplitude.This study provides insights into the evolution of frictional stability in discontinuities and is beneficial for controlling relative disasters in fault zones. 展开更多
关键词 Slide-hold-slide test normal load oscillation Frictional healing Fault stability
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Sliding modes of fault activation under constant normal stiffness conditions 被引量:1
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作者 Chuanqing Zhang Jie Xu +3 位作者 Shengji Jin Guojian Cui Yuhang Guo Lingyu Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第5期1213-1225,共13页
Fault activation has been the focus of research community for years.However,the studies of fault activation remain immature,such as the fault activation mode and its major factors under constant normal stiffness(CNS)c... Fault activation has been the focus of research community for years.However,the studies of fault activation remain immature,such as the fault activation mode and its major factors under constant normal stiffness(CNS)conditions associated with large thickness of fault surrounding rock mass.In this study,the rock friction experiments were conducted to understand the fault activation modes under the CNS conditions.Two major parameters,i.e.the initial normal stress and loading rate,were considered and calibrated in the tests.To reveal the response mechanism of fault activation,the local strains near the fault plane were recorded,and the macroscopic stresses and displacements were analyzed.The testing results show that the effect of displacement-controlled loading rate is more pronounced under the CNS conditions than that under constant normal load(CNL)conditions.Both the normal and shear stresses drop suddenly when the stick-slip occurs.The decrease and increase of the normal stress are synchronous with the shear stress in the regular stick-slip scenario,but mismatch with the shear stress during the chaotic stick-slip process.The results are helpful for understanding the fault sliding mode and the prediction and prevention of fault slip. 展开更多
关键词 Fault activation Rock friction mechanics Sliding modes Constant normal stiffness(CNS) Displacement-controlled loading rates ROCKBURST
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半连续Bernoulli-Normal两部回归模型及变量选择
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作者 鲁亚会 江涛 《统计与决策》 北大核心 2023年第7期52-57,共6页
对于半连续两部回归模型,考虑到每个回归部分都会遇到大量的候选变量,此时就会产生变量选择问题。文章主要研究Bernoulli-Normal两部回归模型的变量选择问题。先提出一种基于Lasso惩罚函数的变量选择方法,但考虑到Lasso估计量不具有Ora... 对于半连续两部回归模型,考虑到每个回归部分都会遇到大量的候选变量,此时就会产生变量选择问题。文章主要研究Bernoulli-Normal两部回归模型的变量选择问题。先提出一种基于Lasso惩罚函数的变量选择方法,但考虑到Lasso估计量不具有Oracle性质,又提出一种基于自适应Lasso惩罚函数的变量选择方法。模拟结果表明:两种方法都能够对Bernoulli-Normal回归模型进行变量选择,且自适应Lasso方法的变量选择性能往往优于Lasso方法。 展开更多
关键词 Bernoulli-normal回归模型 变量选择 Lasso惩罚 自适应Lasso惩罚
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THE EXISTENCE AND STABILITY OF NORMALIZED SOLUTIONS FOR A BI-HARMONIC NONLINEAR SCHR?DINGER EQUATION WITH MIXED DISPERSION
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作者 罗庭健 郑世骏 朱世辉 《Acta Mathematica Scientia》 SCIE CSCD 2023年第2期539-563,共25页
In this paper,we study the ground state standing wave solutions for the focusing bi-harmonic nonlinear Schrodinger equation with aμ-Laplacian term(BNLS).Such BNLS models the propagation of intense laser beams in a bu... In this paper,we study the ground state standing wave solutions for the focusing bi-harmonic nonlinear Schrodinger equation with aμ-Laplacian term(BNLS).Such BNLS models the propagation of intense laser beams in a bulk medium with a second-order dispersion term.Denoting by Qpthe ground state for the BNLS withμ=0,we prove that in the mass-subcritical regime p∈(1,1+8/d),there exist orbit ally stable ground state solutions for the BNLS when p∈(-λ0,∞)for someλ0=λ0(p,d,‖Qp‖L2)>0.Moreover,in the mass-critical case p=1+8/d,we prove the orbital stability on a certain mass level below‖Q*‖L2,provided thatμ∈(-λ1,0),where■and Q*=Q1+8/d.The proofs are mainly based on the profile decomposition and a sharp Gagliardo-Nirenberg type inequality.Our treatment allows us to fill the gap concerning the existence of the ground states for the BNLS when p is negative and p∈(1,1+8/d]. 展开更多
关键词 elliptic equations bi-harmonic operator normalized solutions profile decomposition
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Promoting normal childbirth:Research status and application of upright positions in the second stage of labour
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作者 Yu Zang Hong Lu 《International Journal of Nursing Sciences》 CSCD 2023年第1期129-131,共3页
In recent years,more and more attention has been paid to normal childbirth.The World Health Organization(WHO),International Confederation of Midwives(ICM),Chinese Maternal and Child Health Association(CMCHA)have activ... In recent years,more and more attention has been paid to normal childbirth.The World Health Organization(WHO),International Confederation of Midwives(ICM),Chinese Maternal and Child Health Association(CMCHA)have actively advocated normal childbirth[[1],[2],[3]].It is proved that normal childbirth can improve birth outcomes. 展开更多
关键词 BIRTH CHILD normal
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A comparative study for determining rock joint normal stiffness with destructive uniaxial compression and nondestructive ultrasonic wave testing
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作者 Zhenghu Zhang Jianbo Zhu Jianhui Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第7期1700-1712,共13页
Rock joints are one of the vital discontinuities in a natural rock mass.How to accurately and conveniently determine joint normal stiffness is therefore significant in rock mechanics.Here,first,seven existing methods ... Rock joints are one of the vital discontinuities in a natural rock mass.How to accurately and conveniently determine joint normal stiffness is therefore significant in rock mechanics.Here,first,seven existing methods for determining joint normal stiffness were introduced and reviewed,among which MethodⅠ(the indirect measurement method),MethodⅡ(the direct determination method),MethodⅢ(the across-joint strain gauge measurement method)and MethodⅣ(the deformation measuring ring method)are via destructive uniaxial compression testing,while MethodⅤ(the best fitting method),MethodⅥ(the rapid evaluation method)and MethodⅦ(the effective modulus method)are through wave propagation principles and nondestructive ultrasonic testing.Subsequently,laboratory tests of intact and jointed sandstone specimens were conducted following the testing requirements and pro-cedures of those seven methods.A comparison among those methods was then performed.The results show that Method I,i.e.the benchmark method,is reliable and stable.MethodⅡhas a conceptual drawback,and its accuracy is acceptable at only very low stress levels.Relative errors in the results from MethodⅢare very large.With MethodⅣ,the testing results are sufficiently accurate despite the strict testing environment and complicated testing procedures.The results from MethodⅤare greatly unstable and significantly dependent on the natural frequency of the transducers.The joint normal stiffness determined with MethodⅥis stable and accurate,although data processing is complex.MethodⅦcould be adopted to determine the joint normal stiffness corresponding to the rock elastic deformation phase only.Consequently,it is suggested that MethodsⅠ,ⅣandⅥshould be adopted for the mea-surement of joint normal stiffness.The findings could be helpful in selecting an appropriate method to determine joint normal stiffness and,hence,to better solve discontinuous rock mass problems. 展开更多
关键词 normal stiffness Rock joint Uniaxial compression Ultrasonic wave
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Experimental Studies on Cyclic Shear Behavior of Steel-Clay Interface Under Constant Normal Load
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作者 YU Shi-wen WANG Jie +1 位作者 LIU Jun-wei WANG Teng 《China Ocean Engineering》 SCIE EI CSCD 2023年第3期519-524,共6页
The degradation of the shear stress between pile-clay interface caused by undrained cyclic jacking affects the jacking force.A series of large displacement monotonic shear,cyclic shear and post-cyclic monotonic steel ... The degradation of the shear stress between pile-clay interface caused by undrained cyclic jacking affects the jacking force.A series of large displacement monotonic shear,cyclic shear and post-cyclic monotonic steel plate-clay interface shear te sts were performed under the constant normal load(CNL)condition to inve stigate the effects of normal stre ss,cyclic amplitude,and number of cycles on a steel plate-clay interface using the GDS multi-function interface shear tester.Based on the experimental results,in monotonic shear tests,change of shear stress took place in the specimen,the shear stress rapidly reached the peak value at shear displacement of 1 mm,and then abruptly decreased to the residual value.In cyclic shear te sts,accumulated displacement was a better parameter to describe the soil degradation characteristics,and the degradation degree of shear stress became greater with the increasing of normal stress and accumulated displacement.Shear stress in post-cyclic monotonic shear tests did not generate a peak value and was lower than that in monotonic shear tests under the same normal stress.The soil was completely disturbed and reached the residual strength when the cumulative displacement approached 6 m.An empirical equation to evaluate shear stress degradation mechanism was formulated and the procedure of parameter identification was presented. 展开更多
关键词 cyclic shear steel-clay interface constant normal load cumulative displacement residual strength
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THE EXISTENCE OF GROUND STATE NORMALIZED SOLUTIONS FOR CHERN-SIMONS-SCHRODINGER SYSTEMS
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作者 毛宇 吴行平 唐春雷 《Acta Mathematica Scientia》 SCIE CSCD 2023年第6期2649-2661,共13页
In this paper,we study normalized solutions of the Chern-Simons-Schrödinger system with general nonlinearity and a potential in H^(1)(ℝ^(2)).When the nonlinearity satisfies some general 3-superlinear conditions,w... In this paper,we study normalized solutions of the Chern-Simons-Schrödinger system with general nonlinearity and a potential in H^(1)(ℝ^(2)).When the nonlinearity satisfies some general 3-superlinear conditions,we obtain the existence of ground state normalized solutions by using the minimax procedure proposed by Jeanjean in[L.Jeanjean,Existence of solutions with prescribed norm for semilinear elliptic equations,Nonlinear Anal.(1997)]. 展开更多
关键词 Chern-Simons-Schrodinger system non-constant potential Pohozaev identity ground state normalized solution
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