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天然和饱水红砂岩三轴压缩蠕变变形试验研究

三峡大学学报（自然科学版） 2025年第1期47卷 9-15页

作者：刘桃根胡凯李玲王伟湖南工学院土木与建筑工程学院湖南衡阳421002 河海大学岩土工程科学研究所南京210098 江西职业技术大学建筑工程学院江西九江332007

蠕变特性和长期强度是红砂岩地区岩体工程安全评价的关键要素,饱水软化效应对红砂岩蠕变特性和长期强度具有重要影响.采用全自动岩石三轴压缩伺服流变仪,开展天然与饱水红砂岩的三轴压缩试验和三轴压缩蠕变试验.试验结果表明:峰值强度... 详细信息

蠕变特性和长期强度是红砂岩地区岩体工程安全评价的关键要素,饱水软化效应对红砂岩蠕变特性和长期强度具有重要影响.采用全自动岩石三轴压缩伺服流变仪,开展天然与饱水红砂岩的三轴压缩试验和三轴压缩蠕变试验.试验结果表明:峰值强度、弹性模量和蠕变破坏应力因饱水软化效应而降低,围压对其降幅有削弱作用,蠕变破坏应力与峰值强度的比值在0.75~0.98之间;饱水软化效应能增强蠕变瞬时变形,减弱蠕变变形及蠕变应变速率;环向应变比轴向应变更早进入稳态蠕变阶段和加速蠕变阶段;稳态蠕变速率与偏压的变化关系符合指数函数关系;长期强度因饱水软化作用而降低,却因围压增加而增大,长期强度与峰值强度的比值在0.62~0.92之间;裂纹损伤应力与长期强度相差较大,裂纹损伤应力视为长期强度有待进一步考究.

关键词：红砂岩蠕变特性长期强度饱水软化效应裂纹损伤应力

Transformation method and wave control

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Acta Mechanica Sinica 2010年第6期26卷 889-898页

作者： Zheng Chang Jin hu Geng-kai hu School of Aerospace Engineering Beijing Institute of Technology 100081 BeijingChina School of Information and Electronics Beijing Institute of Technology100081 BeijingChina

Transformation method provides an efficient way to control wave propagation by *** transformed relations for field and material during a transformation are essential to fulfill this *** propose a systematic method to derive the transformed relations for a general physic process,the constraint conditions are obtained by considering geometrical and physical constraint during a mapping. The proposed method is applied to Navier＇s equation for elastodynamics,Helmholtz＇s equation for acoustic wave and Maxwell＇s equation for electromagnetic wave,the corresponding transformed relations are derived,which can be used in the framework of transformation method for wave *** show that contrary to electromagnetic wave,the transformed relations are not uniquely determined for elastic wave and acoustic wave,so we have a freedom to choose them *** the obtained transformed relations,we also provide some examples for device design,a concentrator for elastic wave,devices for illusion acoustic and illusion optics are conceived and validated by numerical simulations.

关键词： Wave control Elastic wave Acoustic wave Electromagnetic wave Local affine transformation

Multi-threaded code generation from Signal program to OpenMP

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Frontiers of Computer Science 2013年第5期7卷 617-626页

作者： kai hu Teng ZHANG Zhibin YANG State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China School of Computer Science and Engineering Beihang University Beijing 100191 China IRIT-CNRS Universite de Toulouse Toulouse 31062 France

The use of multi-core processors will become a trend in safety critical systems. For safe execution of multi- threaded code, automatic code generation from formal spec- ification is a desirable method. Signal, a synchronous lan- guage dedicated for the functional description of safety crit- ical systems, provides soundness semantics for determinis- tic concurrency. Although sequential code generation of Sig- nal has been implemented in Polychrony compiler, deter- ministic multi-threaded code generation strategy is still far from mature. Moreover, existing code generation methods use certain multi-thread library, which limits the cross plat- form executions. OpenMP is an application program inter- face （API） standard for parallel programming, supported by several mainstream compilers from different platforms. This paper presents a methodology translating Signal program to OpenMP-based multi-threaded C code. First, the intermedi- ate representation of the core syntax of Signal using syn- chronous guarded actions is defined. Then, according to the compositional semantics of Signal equations, the Signal pro- gram is synthesized to dependency graph （DG）. After par- allel tasks are extracted from dependency graph, the Signal program can be finally translated into OpenMP-based C code which can be executed on multiple platforms.

关键词： multi-thread synchronous language Signal,code generation OpenMP

Rainfall occurrence and its relation to flood damage in China from 2000 to 2015

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Journal of Mountain Science 2018年第11期15卷 2492-2504页

作者： WEI Li hu kai-heng hu Xu-dong Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of Sciences Chengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China University of Chinese Academy of Sciences Beijing 100049 China

China is highly susceptible to flood disasters and subjected to great damage every ***, the flood frequency has exhibited an increasing trend in recent years. Most flood events,including flash floods and river flood, are induced by rainfall. This study investigates annual variations of rainfall occurrence over China during the period from 2000 to 2015 at the national and regional scale using daily rainfall data from the Tropical Rainfall Measuring Mission. The Mann-Kendall test is performed for trend detection, and statistical data of flood damage published by China's government,including destroyed crop area, damaged buildings,direct economic loss, percentage of GDP(gross domestic product), and death toll are correlatively analysed with rainfall occurrences. The results show that storm rain events show the greatest variation among three rainfall types(moderate rain, heavy rain and storm rain). The variation coefficients of rainfall over Northeast China, North China, and Northwest China are the highest, whereas that for Southwest China is the smallest. Moderate rain, heavy rain over Central China, and moderate rain over Southwest China exhibits decreasing trends, whereas the remaining exhibit increasing trends. The correlation between the rainfall occurrences and these flood damage indices at the national scale shows that only direct economic loss has a strong positive correlation with rainfall occurrences, and the other indices have weaker correlations. The correlation is strong in three north regions, except for death toll in Northwest China. In contrast, the correlation between flood damage and rainfall is weak in East China, Central China, Southwest China, and South China. Overall,death toll is strongly correlated with the number of damaged buildings, implying that flood fatalities in China are likely associated with building collapse, and are dominated by specific extreme events. This study can provide a scientific reference for flood management in

关键词： Flood damage Rainfall occurrence Storm rainfall Coefficient of variation

Grain-size effect on dislocation source-limited hardening and ductilization in bulk pure Ni

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Journal of Materials Science & Technology 2023年第23期154卷 9-21页

作者： kai hu Jun Yi Bo huang Gang Wang Institute of Materials School of Materials Science and Engineering Shanghai University Shanghai 200444 China

Dislocation source-limited hardening and ductilization is an effective strategy to obtain superior strength-ductility synergy in some engineering structural metals. Recent works demonstrated that the synergy could be enhanced by grain-size reduction. However, the mechanism of grain-size dependence is still a mystery. In this work, bulk pure Ni produced by electrodeposition and subsequent annealing, with grain sizes ranging from ∼20 nm to ∼20 µm, were methodically investigated to unravel the mechanism of the grain-size effect on dislocation source-limited hardening and ductilization. The high-density nano-twinning in the as-electrodeposited nanograined specimens exhibited better thermodynamic stability than the peers with random high-angle grain boundaries, leading to fine recrystallized grains with low-density dislocations. The low dislocation density enabled extra hardening beyond grain boundary strengthening via yield-point behavior with grain sizes ranging from ∼110 nm to ∼10 µm and extra ductilization over ∼500 nm. This work demonstrated that the prerequisite for dislocation source-limited hardening was that the dislocation density of the specimen should be lower than the size-dependent critical value of ((1.1 × 107 /d ) m^(–2), d is the grain size in unit of the meter) where a transition from forest-dominated hardening to dislocation source-limited hardening could occur. On the other hand, dislocation source-limited ductilization only worked when the grain size was comparable to/larger than the theoretical dislocation mean slip distance. Dislocation source-limited ductilization resulted from more room in grains for accumulation of dislocations and deformation nano-stacking faults enabling the higher work hardening rate. This work offered an altogether new avenue to obtain stronger and more ductile metallic materials through utilizing grain-size dependent dislocation source-limited hardening and ductilization.

关键词： Dislocation source-limited hardening Dislocation source-limited ductilization Grain size Yield point Hall-Petch slope

Green Therapy of Cancer:A Promising Grope for Anticancer Strategy by Modern Chinese Medicine

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Chinese Journal of Integrative Medicine 2018年第8期24卷 568-572页

作者： ZHOU Tian hu kai-wen Department of Oncology Dongfang Hospital Affiliated to Beijing University of Chinese Medicine

In 2003, a 61-year old highly respected director of the Surgery Department of Dongfang Hospital Affiliated to Beijing University of Chinese Medicine was diagnosed as advanced lung cancer, moderately differentiated adenocarcinoma, coverinqmore than two thirds of the thoracic aorta, multiple mediastinal nodal metastases, pleural effusion ＂Only 3 months could be expected＂, a cruel fact came out after deliberation of many seasoned medical specialists. In the whole career of this surgery professor, he used the lancet as his weapon to save lives. But this time after weighing the pros and cons again and again, he required a ＂tender＂ plan with no lancet.

关键词： CGT In Green Therapy of Cancer:A Promising Grope for Anticancer Strategy by Modern Chinese Medicine QOL

A debris-flow impact pressure model combining material characteristics and flow dynamic parameters

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Journal of Mountain Science 2018年第12期15卷 2721-2729页

作者： TANG Jin-bo hu kai-heng Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Impact force is a crucial factor to be considered in debris-resisting structure design. The impact of debris flow against a structural barrier depends not only on the flow dynamics but also on the barrier material. Based on the structural vibration equation and energy conservation law, a simple model for calculating debris-flow impact pressure is proposed, which includes the mechanical impedance of the material, debris-flow velocity and Froude number. Twenty-five impact tests have been conducted using different kinds of materials: steel, black granite, white granite, marble and polyvinyl chloride(PVC) board, and the ratio of the maximum impact time to the vibration period of the structure is determined for the model. It is found that the ratio's square root shows a linear relationship with the material solid Froude number. This indicates that the impedance of the structures plays an important role in the flow-barrier interaction. Moreover, the debrisflow impact force is found to decrease with the travel time of the elastic stress wave though the structures.

关键词： Debris flows Impact pressure Dynamical responses Mechanical impedance

Contrasting Impacts of South and North Tropical Indian Ocean Sea Surface Temperature Anomalies on East Asian Summer Climate

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Atmospheric and Oceanic Science Letters 2015年第6期8卷 327-332页

作者： hu kai-Ming State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics & Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences

Using observational data and model simulations,the author find that the North Indian Ocean(NIO)sea surface temperature(SST)anomalies can trigger an eastward atmospheric Kelvin wave propagating into the equatorial western Pacific,inducing an anomalous anticyclone over the subtropical Northwest Pacific(NWP)and resulting in prominent summer climate anomalies in the East Asia-Northwest Pacific(EANWP)***,the response of tropospheric temperatures and atmospheric Kelvin waves to the South Indian Ocean(SIO)SST anomalies is weak;as a result,the impact of the SIO SST anomalies on the EANWP summer climate is *** contrasting impacts of NIO and SIO SST anomalies on the EANWP summer climate is possibly due to the different mean state of SSTs in the two *** summer,the climatological SSTs in the NIO are higher than in the SIO,leading to a stronger response of atmospheric convection to the NIO SST anomalies than to the SIO SST ***,compared with the SIO SST anomalies,the NIO SST anomalies can lead to stronger tropospheric air temperature anomalies and atmospheric Kelvin waves to affect the EANWP summer climate.

关键词： Indian Ocean Northwest Pacific anticyclone East As

A Scalable Infrastructure for Online Performance Analysis on CFD Application

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Chinese Journal of Aeronautics 2012年第4期25卷 546-558页

作者： hu kai DING Yi ZHANG Xinyu JIANG Shu School of Computer Science and Engineering Beihang UniversityBeijing 100191China

The fast-growing demand of computational fluid dynamics（CFD） application for computing resources stimulates the development of high performance computing（HPC） and meanwhile raises new requirements for the technology of parallel application performance monitor and *** response to large-scale and long-time running for the application of CFD,online and scalable performance analysis technology is required to optimize the parallel programs as well as to improve their operational *** a result,this research implements a scalable infrastructure for online performance analysis on CFD application with homogeneous or heterogeneous *** infrastructure is part of the parallel application performance monitor and analysis system（PAPMAS） and is composed of two modules which are scalable data transmission module and data storage *** paper analyzes and elaborates this infrastructure in detail with respect to its design and ***,some experiments are carried out to verify the rationality and high efficiency of this infrastructure that could be adopted to meet the practical needs.

关键词： computational aerodynamics computational fluid dynamics scalability online analysis data transmission data storage