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基于局部粗粒化离散元的冰水堆积体隧道围岩破坏特征与加固措施研究

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岩石力学与工程学报 2021年第3期40卷 576-589页

作者：谢亦朋张聪阳军生陈彬傅金阳祝志恒中南大学土木工程学院湖南长沙410075 中南林业科技大学土木工程学院湖南长沙410004 中铁五局集团有限公司湖南长沙410007

以川藏铁路拉林段藏噶隧道穿越冰水堆积体段为工程背景,基于数字图像技术与离散元方法,在识别冰水堆积体的工程地质特征的基础上,提出一种考虑块石真实形态特征的冰水堆积体局部粗粒化模拟方法,并通过数值计算探讨隧道开挖引起的冰水堆... 详细信息

以川藏铁路拉林段藏噶隧道穿越冰水堆积体段为工程背景,基于数字图像技术与离散元方法,在识别冰水堆积体的工程地质特征的基础上,提出一种考虑块石真实形态特征的冰水堆积体局部粗粒化模拟方法,并通过数值计算探讨隧道开挖引起的冰水堆积体围岩破坏特征以及细观破坏机制,最终提出相应的预加固措施。研究结果表明,冰水堆积体隧道围岩在开挖后沿全环渐进式破坏,具体表现为"初始松动区形成-剪切破裂面发育-松动区扩展-剪切破裂面延伸"的动态循环过程,松动区内的颗粒接触劣化证明了土体间的剪切破裂的发育扩展。此外,力链结构特征的演化规律揭示了强力链结构由环状退化为链状,最终导致块石骨架失效、围岩松动破坏这一细观机制。工程应用结果表明,提出的"全断面帷幕注浆+超前管棚+小导管"的预加固措施可显著抑制冰水堆积体隧道围岩破裂面与松动区的发育,有效控制围岩开挖稳定,钻孔取芯与隧道变形监测均满足工程需求。

关键词：隧道工程冰水堆积体隧道局部粗粒化离散元模拟破坏特征围岩预加固

京珠高速公路洋碰隧道水害原因分析及安全性评价

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隧道建设（中英文） 2020年第5期40卷 747-754页

作者：刘浩祝志恒李林毅广东交科检测有限公司广东广州510550 中南大学土木工程学院湖南长沙410075

针对降雨引发的岩溶地区隧道水害影响隧道运营安全问题,以京珠高速公路洋碰隧道为例,通过地质勘探与水连通试验,探明隧址区不良地质情况与水连通特性,采用数值仿真方法探究雨后高水压下隧道结构应力场、渗流场的特征规律,并结合病害情... 详细信息

针对降雨引发的岩溶地区隧道水害影响隧道运营安全问题,以京珠高速公路洋碰隧道为例,通过地质勘探与水连通试验,探明隧址区不良地质情况与水连通特性,采用数值仿真方法探究雨后高水压下隧道结构应力场、渗流场的特征规律,并结合病害情况提出整治措施。研究结果表明:1)地表强降雨、地层岩溶发育、灌入式雨水下渗通道是此次水害的主要原因,而这些原因综合导致的隧道外水压力过高是病害发生的直接原因;2)由于排水能力相对不足,地层高水头下隧道结构(尤其是隧底和拱顶)仍承受较高水压力,大幅削弱了衬砌结构安全性,易引发边墙、隧底的裂损问题;3)采取"增设泄水廊道+地表封堵及引流+增设边墙泄水孔"的整治措施后,整治效果良好。

关键词：高速公路隧道水害岩溶高密度电法水连通试验数值模拟

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用于玻璃温室天沟连接处的断桥式螺栓研究

现代工业经济和信息化 2022年第8期12卷 240-243页

作者：朱志恒山东农业大学山东泰安271018

研发了玻璃温室天沟连接使用的节能型变径断桥式螺栓,运用数值模拟的方法研究了该螺栓的变形及传热过程,用公式计算的方法计算了该螺栓的传热量,确定了该螺栓的抗拉强度。研究结果表明,该变径断桥式螺栓相对于普通的钢制螺栓保温性能提... 详细信息

研发了玻璃温室天沟连接使用的节能型变径断桥式螺栓,运用数值模拟的方法研究了该螺栓的变形及传热过程,用公式计算的方法计算了该螺栓的传热量,确定了该螺栓的抗拉强度。研究结果表明,该变径断桥式螺栓相对于普通的钢制螺栓保温性能提高了96.4%,抗拉强度为22.57 MPa,能够满足天沟连接的强度需求。

关键词：玻璃温室天沟断桥式螺栓保温性能

Few-shot incremental radar target recognition framework based on scattering-topology properties

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Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI Weigang zhu Bakun zhu Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China Department of Electronic and Optical Engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new classes of ISAR *** this paper,a few-shot incremental target recognition framework based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old knowledge,and improves compatibility with new ***,a feature embedding network,with few parameters,is designed based on the graph neural *** embedding network is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brownian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new classes with old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brownian distance metric Graph neural networks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

Stress-strain relationship for reactive powder concrete with recycled powder under uniaxial compression

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1015-1027页

作者： Peng zhu Yunming zhu Wenjun QU Liyu XIE College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China

The recycled powder(RP)from construction wastes can be used to partially replace cement in the preparation of reactive powder *** this paper,reactive powder concrete mixtures with RP partially replacing cement,and natural sand instead of quartz,are *** curing is used,instead of steam curing that is normally requested by standard for reactive powder *** influences of RP replacement ratio(0%,10%,20%,30%),silica fume proportion(10%,15%,20%),and steel fiber proportion(0%,1%,2%)are *** effects of RP,silica fume,and steel fiber proportion on compressive strength,elastic modulus,and relative absorption energy are analyzed,and theoretical models for compressive strength,elastic modulus,and relative absorption energy are established.A constitutive model for the uniaxial compressive stress-strain relationship of reactive powder concrete with RP is *** the increase of RP replacement ratio from 0% to 30%,the compressive strength decreases by 42% and elastic modulus decreases by 24%.

关键词： recycled powder reactive powder concrete elastic modulus relative absorbed energy stress-strain relationship

Carbon Emission Effects Driven by Evolution of Chinese Dietary Structure from 1987 to 2020

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Chinese Geographical Science 2024年第1期34卷 181-194页

作者： zhu Yuanyuan ZHANG Yan zhu Xiaohua Key Laboratory of Geographic Process Analysis&Simulation Hubei Province Central China Normal UniversityWuhan430079China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important *** study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary *** results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption *** dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality *** the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing *** per capita food carbon emissions of residents in urban and rural showed an overall upward *** total food carbon emissions in urban increased significantly,while that in rural increased first and then *** influence of beef and mutton on carbon emissions is the highest in dietary *** with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.

关键词： dietary structure structural evolution carbon emission effects carbon neutrality China

Designing hierarchical structures for innovative cooling textile

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Nano Research 2024年第10期17卷 9202-9224页

作者： Xiran Du Jinlei Li Bin zhu Jia zhu National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210023China School of Sustainable Energy and Resources Nanjing UniversitySuzhou 215163China

The potential of personal cooling technologies in reducing air conditioning energy consumption and enhancing human thermal comfort is *** review focuses on recent advancements in hierarchical structure design for innovative cooling *** with insights into fundamental heat transfer processes between the human body,textile,and the surroundings,we uncover key control *** the advanced hierarchical structure designs enabling effective radiation,sweat evaporation,conduction management,and integration of cold energy sources for realizing effective human body cooling are systematically ***,we explore multifunctional designs beyond cooling,including switchable cooling-heating and ***,we engage in discussions on unifying cooling performance tests and additional multiple requirements to make strides toward practical *** review is anticipated to be a valuable resource,providing the scientific and industrial communities with a quick grasp of past advancements,current challenges,and future directions in achieving effective human body cooling.

关键词： thermal comfort personal cooling textile hierarchical structures

Old Pinus massoniana forests benefit more from recent rapid warming in humid subtropical areas of central-southern China

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JOURNAL OF FORESTRY RESEARCH 2024年第1期35卷 1-16页

作者： Li, Wenxin zhu, Liangjun zhu, Lianhua Jing, Mengdan Qian, Censhi zhu, Yu Cherubini, Paolo Cent South Univ Forestry & Technol Coll Life Sci & Technol Changsha 410004 Peoples R China Swiss Fed Inst Forest Snow & Landscape Res WSL CH-8903 Birmensdorf Switzerland Univ British Columbia Fac Forestry Dept Forest & Conservat Sci 3041-2424 Main Mall Vancouver BC V6T 1Z4 Canada

Trees progress through various growth stages, each marked by specific responses and adaptation strategies to environmental conditions. Despite the importance of age-related growth responses on overall forest health and management policies, limited knowledge exists regarding age-related effects on dendroclimatic relationships in key subtropical tree species. In this study, we employed a dendrochronological method to examine the impact of rapid warming on growth dynamics and climatic sensitivity of young (40-60 years) and old (100-180 years) Pinus massoniana forests across six sites in central-southern China. The normalized log basal area increment of trees in both age groups increased significantly following rapid warming in 1984. Trees in young forests further showed a distinct growth decline during a prolonged severe drought (2004-2013), whereas those in old forests maintained growth increases. Tree growth was more strongly influenced by temperature than by moisture, particularly in old forests. Spring temperatures strongly and positively impacted the growth of old trees but had a weaker effect on young ones. Old forests had a significantly lower resistance to extreme drought but faster recovery compared to young forests. The "divergence problem" was more pronounced in younger forests due to their heightened sensitivity to warming-induced drought and heat stress. With ongoing warming, young forests also may initially experience a growth decline due to their heightened sensitivity to winter drought. Our findings underscore the importance of considering age-dependent changes in forest/tree growth response to warming in subtropical forest management, particularly in the context of achieving "Carbon Peak & Carbon Neutrality" goals in China.

关键词： Tree rings Pinus massoniana Age effects Drought resilience Subtropical forests Rapid warming TREE-RING EVIDENCE CLIMATE-CHANGE GROWTH ENHANCEMENT SPRING PHENOLOGY RADIAL GROWTH TEMPERATURE CARBON NORTHERN DECLINE PHOTOSYNTHESIS

Synergistic catalysis of the N-hydroxyphthalimide on flower-like bimetallic metal-organic frameworks for boosting oxidative desulfurization

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Petroleum Science 2024年第1期21卷 674-682页

作者： Jing He Kun zhu Wei Jiang Dong-Ao zhu Lin-Hua zhu Hai-Yan Huang Wen-Shuai zhu Hua-Ming Li Institute for Energy Research Jiangsu UniversityZhenjiang212013JiangsuChina College of Chemistry and Chemical Engineering Hainan Normal UniversityKey Laboratory of Water Pollution Treatment and Resource Reuse of Hainan ProvinceHaikou571158HainanChina

Synergic catalytic effect between active sites and supports greatly determines the catalytic activity for the aerobic oxidative desulfurization of fuel *** this work,Ni-doped Co-based bimetallic metal-organic framework(CoNi-MOF)is fabricated to disperse N-hydroxyphthalimide(NHPI),in which the whole catalyst provides plentiful synergic catalytic effect to improve the performance of oxidative desulfurization(ODS).As a bimetallic MOF,the second metal Ni doping results in the flower-like morphology and the modification of electronic properties,which ensure the exposure of NHPI and strengthen the synergistic effect of the overall *** with the monometallic Co-MOF and naked NHPI,the NHPI@CoNi-MOF triggers the efficient activation of molecular oxygen and improves the ODS performance without an *** sulfur removal of dibenzothiophene-based model oil reaches 96.4%over the NHPI@CoNi-MOF catalyst in 8 h of ***,the catalytic product of this aerobic ODS reaction is sulfone,which is adsorbed on the catalyst surface due to the difference in *** work provides new insight and strategy for the design of a strong synergic catalytic effect between NHPI and bimetallic supports toward high-activity aerobic ODS materials.

关键词： Metal-organic frameworks Doped Bimetallic N-hydroxyphthalimide Aerobic processes Oxidative desulfurization