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International Journal of Mining Science and Technology 2022年第3期32卷 487-497页

作者： Longjun Dong Qing Tao qingchun hu Sijia Deng Yongchao Chen Qiaomu Luo Xihong Zhang School of Resources and Safety Engineering Central South UniversityChangsha 410083China School of Civil and Mechanical Engineering Curtin UniversityPerth 6102Australia

Acoustic emission(AE)localization plays an important role in the prediction and control of potential hazardous sources in complex ***,existing location methods have less discussion on the presence of unknown empty *** paper proposes an AE source location method for structures containing unknown empty areas(SUEA).Firstly,this method identifies the shape,size,and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE ***,the unknown AE source can be located considering the identified empty *** lead break experiments were performed to verify the effectiveness and accuracy of the proposed *** specimens were selected containing empty areas with different positions,shapes,and *** show the average location accuracy of the SUEA increased by 78%compared to the results of the existing *** can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels,bridges,railroads,and caves in practical engineering.

关键词： Acoustic emission Source location Empty area identification

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热流道板真空钎焊有限元模拟与分析

焊接 2024年第2期 51-56,73页

作者：胡青春滕智姜晓平梁灿棉华南理工大学广州510641 广东星联精密机械有限公司广东佛山528251

采用BNi-2镍基钎料对热流道板进行真空钎焊,须根据钎焊件设定加热工艺曲线。加热工艺曲线的设定是钎焊过程最重要的环节之一,决定着钎焊的质量和效率。该文结合真空加热的特点及钎焊要求,运用Ansys有限元软件数值模拟的方法,对壁厚、体... 详细信息

采用BNi-2镍基钎料对热流道板进行真空钎焊,须根据钎焊件设定加热工艺曲线。加热工艺曲线的设定是钎焊过程最重要的环节之一,决定着钎焊的质量和效率。该文结合真空加热的特点及钎焊要求,运用Ansys有限元软件数值模拟的方法,对壁厚、体积较大的多层热流道板真空钎焊进行仿真分析,通过对比不同工艺方案及不同钎焊件的模拟结果,探究真空钎焊过程升温规律,从而调整各阶段的相关参数及制定合理的加热工艺曲线,避免了现场反复调试参数造成的资源浪费,节约了时间和成本,提高了效率。此外,通过在实际钎焊试验过程中布置热电偶对钎焊件测量温度,并与数值模拟结果对比,两者基本吻合,验证了有限元分析的准确性,能为之后其他零部件的真空钎焊提供参考。

关键词：热流道板真空钎焊加热工艺曲线数值模拟

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Velocity-Free MS/AE Source Location Method for Three-Dimensional Hole-Containing Structures

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Engineering 2020年第7期6卷 827-834页

作者： Longjun Dong qingchun hu Xiaojie Tong Youfang Liu School of Resources and Safety Engineering Central South UniversityChangsha 410083China Department of Geophysics Colorado School of MinesGoldenCO 80401USA

Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex ***,the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing *** meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures,a velocity-free MS/AE source location method is developed in this *** avoids manual repetitive training by using equidistant grid points to search the path,which introduces A*search algorithm and uses grid points to accommodate complex structures with irregular *** also takes advantage of the velocity-free source location *** verify the validity of the proposed method,lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm10 cm10 *** was cut out into a cylindrical empty space with a size of/6cm10 *** on the arrivals,the classical Geiger method and the proposed method are used to locate lead-breaking *** show that the locating error of the proposed method is 1.20 cm,which is less than 2.02 cm of the Geiger ***,the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.

关键词： Microseismic source Acoustic emission Velocity-free location method Three-dimensional hole-containing structures

A DAMAGE MECHANICS MODEL FOR FATIGUE LIFE PREDICTION OF FIBER REINFORCED POLYMER COMPOSITE LAMINA

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Acta Mechanica Solida Sinica 2011年第5期24卷 399-410页

作者： Wenjing Shi Weiping hu Miao Zhang qingchun Meng Institute of Solid Mechanics School of Aeronautics Science and Engineering BeiHang University Beijing 100191 China

A damage mechanics fatigue life prediction model for the fiber reinforced polymer lamina is established. The stiffness matrix of the lamina is derived by elastic constants of fiber and matrix. Two independent damage degrees of fiber and matrix are introduced to establish constitutive relations with damage. The damage driving forces and damage evolution equations for fiber and matrix are derived respectively. Fatigue tests on 0° and 90° unidirectional laminates are conducted respectively to identify parameters in damage evolution equations of fiber and matrix. The failure criterion of the lamina is presented. Finally, the life prediction model for lamina is proposed.

关键词： fiber reinforced polymer composite lamina continuum damage mechanics fatigue life prediction fiber breakage matrix cracking

Prognostic implications of overt congestion in heart failure with preserved ejection fraction and the interaction with spironolactone:Insights from TOPCAT

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Chinese Medical Journal 2024年第10期137卷 1249-1251页

作者： Yingwen Lin Hengli Zhao Dongtu hu Jia huang You Peng Juncong Li Dingli Xu qingchun Zeng State Key Laboratory of Organ Failure Research Department of CardiologyNanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China Guangdong Provincial Key Laboratory of Clinical Pharmacology Medical Research InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhouGuangdong 510515China Department of Radiology The Third Affiliated Hospital of Guangzhou Medical UniversityGuangzhouGuangdong 510150China Department of Obstetrics and Gynecology Nanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China

To the Editor:Heart failure with preserved ejection fraction(HFpEF)is a clinical entity characterized by impaired diastolic *** recently,there have been few studies directly evaluating how volume status impacts future cardiac events for patients with *** supporting the application of spironolactone in HFpEF is mainly derived from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist(TOPCAT)*** though primary analysis of the trial reached a neutral result,subgroup and subsequent post hoc analyses have confirmed its efficacy in selected groups of patients,suggesting that identifying the potential subgroups of patients who would benefit from spironolactone treatment is important.[1]Data regarding the impact of congestion status on the efficacy of spironolactone in HFpEF are lacking.

关键词： function. fraction impaired

Simulation Analysis on Quasistatic Characteristics of Multistage Face Gears with Double Crown Surfac

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Computer Modeling in Engineering & Sciences 2019年第2期118卷 447-470页

作者： Xingbin Chen qingchun hu Zhongyang Xu Yao Ding Qianli Mai Chune Zhu School of Mechanical and Automotive engineering South China University of TechnologyGuangzhou510641China eBizprise Technology(TJ)Limited Tianjin300040China Institute for Biomedical and Pharmaceutical Sciences Guangdong University of TechnologyGuangzhou510006China.

The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical ***,it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number ***,the interference problems between two stages and big stress concentration are *** crown surface configuration technology and structure design were introduced to optimize the meshing *** improve the double crown design feasibility and meshing stability,it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various influence factors on the contact condition and quasi-static characteristics of multistage face gears *** relevant scatter plots are fitted by comparing the contact results with different crown quantities and friction coefficients to intuitively obtain the variation regularity of maximum deformation,maximum strain,maximum stress and maximum strain *** natural frequency and mode coefficient are also determined by modal analysis under these two *** the above mentioned studies verified the contact conjugate properties of double crown surface configuration were *** results can provide a foundation for structure optimization and transmission reliability of multistage face gears.

关键词： Multistage face gears quasi-static contact characteristics modal characteristics double crown surface simulation analysis.

Spatial-temporal differentiation and influencing factors of rural settlements in mountainous areas: an example of Liangshan Yi Autonomous Prefecture, Southwestern China

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Journal of Mountain Science 2024年第1期21卷 218-235页

作者： WANG Yumeng DENG qingchun YANG Haiqing LIU hui YANG Feng ZHAO Yakai School of Geographical Sciences China West Normal UniversityNanchong 637009China Sichuan Provincial Engineering Laboratory of Monitoring and Control for Soil Erosion in Dry Valleys China West Normal UniversityNanchong 637009China Liangshan Soil Erosion and Ecological Restoration in Dry Valleys Observation and Research Station Xide 616753China

Rural settlement is the basic spatial unit for compact communities in rural area. Scientific exploration of spatial-temporal differentiation and its influencing factors is the premise of spatial layout rationalization. Based on land use data of Liangshan Yi Autonomous Prefecture(hereinafter referred to as Liangshan Prefecture) in Sichuan Province, China from 1980 to 2020, compactness index, fractal dimension, imbalance index, location entropy and the optimal parameters-based geographical detector(OPGD) model are used to analyze the spatial-temporal evolution of the morphological characteristics of rural settlements, and to explore the influence of natural geographical factors, socioeconomic factors, and policy factors on the spatial differentiation of rural settlements. The results show that:(1) From 1980 to 2020, the rural settlements area in Liangshan Prefecture increased by 15.96 km^(2). In space, the rural settlements are generally distributed in a local aggregation, dense in the middle and sparse around the periphery. In 2015, the spatial density and expansion index of rural settlements reached the peak.(2) From 1980 to 2020, the compactness index decreased from 0.7636 to 0.7496, the fractal dimension increased from 1.0283 to 1.0314, and the fragmentation index decreased from 0.1183 to 0.1047. The spatial morphological structure of rural settlements tended to be loose, the shape contour tended to be complex, the degree of fragmentation decreased, and the spatial distribution was significantly imbalanced.(3) The results of OPGD detection in 2015 show that the influence of each factor is slope(0.2371) > traffic accessibility(0.2098) > population(0.1403) > regional GDP(0.1325) > elevation(0.0987) > poverty alleviation(0). The results of OPGD detection in 2020 show that the influence of each factor is slope(0.2339) > traffic accessibility(0.2198) > population(0.1432) > regional GDP(0.1219) > poverty alleviation(0.0992) > elevation(0.093). Natural geographical facto

关键词： Rural settlements Location entropy Geographical detector Spatiotemporal differentiation Influencing factors

Amelioration of habitat since the early Holocene contributed to the origin of agriculture in the farming-pastoral zone of northern China

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Science China Earth Sciences 2024年第8期67卷 2535-2546页

作者： Xin JIA Zhiping ZHANG Yonggang SUN Runqi JIANG Shuangwen YI Wei CHEN Jue SUN Guoqiang LI Shuzhi WANG Enrui LI Xiaonong hu qingchun BAO Harry F.LEE huayu LU Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Schlool of History and Culture Chifeng UniversityChifeng 024000China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Institute of Archaeology Chinese Academy of Social SciencesBeijing 100710China Ulanqab Museum Ulanqab 012000China The Institute of Cultural Relics and Archaeology Hohhot 010011China Department of Geography and Resource Management The Chinese University of Hong KongHong Kong 999077China Key Laboratory of Virtual Geographic Environment(Ministry of Education of PRC) Nanjing Normal UniversityNanjing 210023China School of Geography Nanjing Normal UniversityNanjing 210023China Institute of Environmental Archaeology Nanjing Normal UniversityNanjing 210023China

The origin of agriculture in the farming-pastoral zone of northern China remains in *** central region of the Inner Mongolia Plateau is located in the core area of the farming-pastoral zone;thus,it is a critical region for exploring the origin of the dryland farming system in northern *** study selected the Yumin Site and Banan Site,which belong to the Yumin Culture-the beginning of Neolithic culture in Inner Mongolia-as the research *** on the quartz optically stimulated luminescence(OSL)dating on the sedimentary sections from the Yumin site(YM)and Banan site(BN1 and BN2),the Holocene chronology framework of each section was *** that,by identifying carbonized grains in the Yumin site and the multi-proxy analysis of each section,we investigated the relationship between the origin of agriculture and climate change in this *** results revealed that the timing of the origin of agriculture recorded in the Yumin site lagged behind the timing of a significant increase of precipitation during the early Holocene but coincided with the timing of a significant increase of vegetation around 8.4 *** phenomenon was further confirmed by the published high-resolution paleoenvironmental records from the surrounding area of the Yumin *** propose that with the gradual amelioration of hydrothermal conditions since the beginning of the Holocene,the regional ecosystem had been improved,resulting in the gradual conversion of the land surface from infertile sand to organic-rich soil,providing an appropriate environmental foundation for the origin of dryland farming in northern China around 8.4 *** study highlighted that the“accumulative environmental effects”during the early Holocene played a vital role in the origin of agriculture in northern China and provided a reference for agricultural management in the context of future climate change.

关键词： Origin of agriculture Accumulative environmental effects Yumin Culture Northern China Holocene

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Extraction and bioactivities of the chemical composition from Pleurotus ostreatus:a review

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Journal of Future Foods 2024年第2期4卷 111-118页

作者： qingchun Zhao Xiaopeng Liu Lili Cui Changyang Ma National R&D Center for Edible Fungus Processing Technology Henan UniversityKaifeng 475004China Functional Food Engineering Technology Research Center Kaifeng 475004China Joint International Research Laboratory of Food&Medicine Resource Function Kaifeng 475004China

Pleurotus ostreatus as an edible mushroom with pharmacological potential,belonging to class basidiomycetes of kingdom Mycota is known to have immense therapeutic *** contains polysaccharides,proteins,sterols,volatile oils and *** has a variety of biological activities,including anti-oxidant,anti-hyperlipidemic,anti-tumor,immunoregulatory and *** paper summarizes the extraction methods,chemical components and biological activities of ***,and find it is good resources to develop medicine and health food.

关键词： Pleurotus ostreatus Extraction methods Chemical components Biological activities

Integrated neural tracing and in-situ barcoded sequencing reveals the logic of SCN efferent circuits in regulating circadian behaviors

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Science China(Life Sciences) 2024年第3期67卷 518-528页

作者： Meimei Liao Xinwei Gao Chen Chen Qi Li qingchun Guo He huang Erquan Zhang Dapeng Ju College of Biological Sciences China Agriculture UniversityBeijing 100193China National Institute of Biological Sciences(NIBS) Beijing 102206China Chinese Institute for Brain Research Beijing 102206China School of Biomedical Engineering Capital Medical UniversityBeijing 100069China Department of Anesthesiology The Second Affiliated HospitalChongqing Medical UniversityChongqing 401336China Tsinghua Institute of Multidisciplinary Biomedical Research Tsinghua UniversityBeijing 102206China

The circadian clock coordinates rhythms in numerous physiological processes to maintain organismal homeostasis. Since the suprachiasmatic nucleus(SCN) is widely accepted as the circadian pacemaker, it is critical to understand the neural mechanisms by which rhythmic information is transferred from the SCN to peripheral clocks. Here, we present the first comprehensive map of SCN efferent connections and suggest a molecular logic underlying these projections. The SCN projects broadly to most major regions of the brain, rather than solely to the hypothalamus and thalamus. The efferent projections from different subtypes of SCN neurons vary in distance and intensity, and blocking synaptic transmission of these circuits affects circadian rhythms in locomotion and feeding to different extents. We also developed a barcoding system to integrate retrograde tracing with in-situ sequencing, allowing us to link circuit anatomy and spatial patterns of gene expression. Analyses using this system revealed that brain regions functioning downstream of the SCN receive input from multiple neuropeptidergic cell types within the SCN, and that individual SCN neurons generally project to a single downstream brain *** map of SCN efferent connections provides a critical foundation for future investigations into the neural circuits underlying SCNmediated rhythms in physiology. Further, our new barcoded tracing method provides a tool for revealing the molecular logic of neuronal circuits within heterogeneous brain regions.

关键词： circadian rhythms SCN output circuit neural tracing barcoded GFP in situ sequencing