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Mechanical responses of anchoring structure under triaxial cyclic loading

Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 545-560页

作者： Peng Wang Nong Zhang qun wei Xingliang Xu Guangzhen Cui Aoran Li Sen Yang Jiaguang Kan State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou221116China School of Civil Engineering Xuzhou University of TechnologyXuzhou221116China School of Mechanical Engineering Jiangsu University of TechnologyChangzhou213001China

Dynamic load on anchoring structures(AS)within deep roadways can result in cumulative damage and failure.This study develops an experimental device designed to test AS under triaxial loads.The device enables the investigation of the mechanical response,failure mode,instability assessment criteria,and anchorage effect of AS subjected to combined cyclic dynamic-static triaxial stress paths.The results show that the peak bearing strength is positively correlated with the anchoring matrix strength,anchorage length,and edgewise compressive strength.The bearing capacity decreases significantly when the anchorage direction is severely inclined.The free face failure modes are typically transverse cracking,concave fracturing,V-shaped slipping and detachment,and spallation detachment.Besides,when the anchoring matrix strength and the anchorage length decrease while the edgewise compressive strength,loading rate,and anchorage inclination angle increase,the failure intensity rises.Instability is determined by a negative tangent modulus of the displacement-strength curve or the continued deformation increase against the general downward trend.Under cyclic loads,the driving force that breaks the rock mass along the normal vector and the rigidity of the AS are the two factors that determine roadway stability.Finally,a control measure for surrounding rock stability is proposed to reduce the internal driving force via a pressure relief method and improve the rigidity of the AS by full-length anchorage and grouting modification.

关键词： Triaxial stress Dynamic-static combination load Cyclic loading Anchoring structure(AS) Cumulative damage

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Propagation form of internal cracks induced by continuous casting soft reduction and control strategy for internal quality

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Journal of Iron and Steel Research(International) 2024年第3期31卷 622-633页

作者： Pu Wang Liang Chen qun-wei Tang wei-tao Li Shao-xiang Li Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China weifang Special Steel Group Co..Ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were investigated.The results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross section.The cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or below.The control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of 0.33-0.99.At this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： Continuous casting Soft reduction Crack propagation Internal quality Control strategy

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Effect of alumina occurrence form on metallurgical properties of hematite and magnetite pellets

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Journal of Iron and Steel Research(International) 2024年第4期31卷 797-809页

作者： Jian Pan Chen-mei Tang Cong-cong Yang De-qing Zhu Zheng-qi Guo wei-qun Huang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina Exploration and Development of Geology and Mineral Resources Co. Ltd.Nanchang 330030JiangxiChina

The effect of alumina occurrence form on the metallurgical properties of both hematite and magnetite pellets was investigated at the same Al_(2)O level of 2 wt.%,including reduction index(RI),low-temperature reduction disintegration index(RDI),reduction swelling index(RSI),and high-temperature softening-dripping performance.The mineralogy of fired pellets was also studied to reveal the influence of alumina occurrence form on the phase composition and microstructure.From the results,the alumina occurrence form presents tremendous impacts on the metallurgical perfor-mance of both magnetite and hematite pellets.Addition of all alumina occurrence forms contributes to inferior reducibility of pellets,especially in the case of gibbsite for magnetite pellets with a RI of 58.4%and kaolinite for hematite pellets with a RI of 56.8%.However,addition of all alumina occurrence forms improves the RDI of magnetite pellets,while there is no significant difference among various alumina occurrence forms.In contrast,alumina occurrence forms have little influence on the RDI of hematite pellets.The presence of free alumina,gibbsite,and kaolinite tends to improve the RSI of hematite and magnetite pellets,whereas hercynite gives the opposite trend with a RSI of 25.6%.For softening-dripping performance of magnetite pellets,all alumina occurrence forms contribute to narrower softening-melting interval.Meanwhile,alumina,gibbsite,and kaolinite give narrower softening-dripping interval,at 229,217,and 88℃,respectively,whereas addition of hercynite results in the largest melting range at 276℃ due to its high melting point.Regarding hematite pellets,free alumina,gibbsite,and hercynite tend to enlarge melting range,whereas kaolinite contributes to lower dripping temperature of 1148℃ and narrow softening-dripping interval of 88℃ due to the formation of a greater amount of slag phase at high temperatures.

关键词： Oxidized pellet Magnetite Hematite Alumina occurrence form Metallurgical performance Blast furnace

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Balanced pairs and relative tilting objects in recollements of abelian categories

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Acta Mathematica Sinica,English Series 2024年

作者： Pei Yu ZHANG Meng Hui LIU Da Jun LIU Jia qun wei School of Mathematics-Physics and Finance Anhui Polytechnic University Department of Mathematics Zhejiang Normal University

In this paper, we study the relationship of balanced pairs in a recollement. As an application of balanced pairs, we introduce the notion of the relative tilting objects, and give a characterization of relative tilting objects, which is similar to Bazzoni characterization of n-tilting modules. Finally, we investigate the relationship of relative tilting objects in a recollement.

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Three new Ag-based full-Heusler alloys:Ag_(2)TiGa,Ag_(2)VGa,and Ag_(2)TiTl

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ChemPhysMater 2022年第3期1卷 211-218页

作者： qun wei Rui Zhang Meiguang Zhang Yun Zhang Linghang Cao Junqin Zhang School of Physics Xidian UniversityXi’an 710071China College of Physics and Optoelectronic Technology Baoji University of Arts and SciencesBaoji 721016China School of Microelectronics Xidian UniversityXi’an 710071China

There are various new structures with superior performance for Heusler alloy materials that are widely used in spintronic materials,thermoelectric materials,and other fields.In this study,three new Ag-based full-Heusler alloys(Ag 2 TiGa,Ag 2 VGa,and Ag 2 TiTl)are proposed.The stability,mechanical properties,and electronic proper-ties of these three new Ag-based Heusler alloys were studied using first-principles calculations.The results showed that the compression resistance,shear resistance,stiffness,and elastic anisotropy of Ag 2 VGa were greater than those of Ag 2 TiGa and Ag 2 TiTl,whereas the ductility of Ag 2 TiGa and Ag 2 TiTl was better than that of Ag 2 VGa.The spin density of states of Ag 2 VGa has evident spin splitting near the Fermi level,and the total magnetic moment of the Ag 2 VGa structure is 2.28μB,which indicates that Ag 2 VGa is magnetic.These studies enrich research on Ag-based Heusler alloys and provide theoretical references for subsequent theoretical and experimental research.

关键词： Heusler alloys Frist-principles calculations Mechanical properties Magnetic properties

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产业数字化对地区税收收入的影响研究

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当代财经 2024年第1期 46-58页

作者：席卫群杨青瑜江西财经大学财税与公共管理学院江西南昌330013

加快推进产业数字化,既是实现经济高质量发展的必然选择,也是促进地区税收收入增长的必由之路。为此,在阐释产业数字化、地区全要素生产率和地区税收收入三者之间关系的基础上,利用2011—2019年我国省级面板数据,实证分析产业数字化对... 详细信息

加快推进产业数字化,既是实现经济高质量发展的必然选择,也是促进地区税收收入增长的必由之路。为此,在阐释产业数字化、地区全要素生产率和地区税收收入三者之间关系的基础上,利用2011—2019年我国省级面板数据,实证分析产业数字化对地区税收收入的影响及作用机制。研究表明:产业数字化能够显著地促进地区税收收入增长,且产业数字化在不同地区、不同税种、不同工业化程度中呈现一定的异质性特征。机制分析发现,产业数字化会促进地区税收收入增长,是通过作用于地区全要素生产率实现的。因此,需要持续深入地推进产业数字化发展,提高地区全要素生产率,进而促进税收收入效应的提升;同时完善现行税收制度,制定区域性税收扶持政策,缩小区域间“数字鸿沟”,并进一步加强税收征管力度,减少产业数字化的地区间税收收入转移效应和流失效应。

关键词：数字经济产业数字化地区税收收入税收征管全要素生产率

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Relationship between LTP and the nuclear protein induced by calcineurin

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Chinese Science Bulletin 1998年第16期43卷 1384-1387页

作者： Jie Luo qun wei Beijing Normal Univ Dept Biol Biochem & Mol Biol Lab Beijing 100875 Peoples R China

Results demonstrate that calcineurin plays a role in long term potentiation (LTP) in the hippocampus. A 45 ku enzyme was administered, which exhibits Ca 2+/calmodulin independent activity to rats, and the protein components of nuclear extracts from the cell-free system of rat hippocampus were tested. It is found that the level of a component significantly increased in nuclear extracts following the activation of calcineurin. The concentration of the component in the nucleus is also markedly increased following hippocampal LTP elicited by ginsenosides. These results suggest that the activation of calcineurin induces a pre-existing protein component to translocate to the nucleus in the hippocampus. The nuclear translocation of the component may be required for LTP in the hippocampus.

关键词： calcineurin nuclear protein learning and memory long-term potentiation (LTP).

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小麦绿色高产栽培技术

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农业技术与装备 2024年第2期 160-162页

作者：魏群连云区农村产权交易中心(连云区农业技术指导站) 江苏连云港222000

传统栽培技术模式下,小麦产量与质量并不理想,导致种植效益较差,影响粮食安全稳定性,不利于小麦产业可持续发展,在此背景下,积极创新应用小麦绿色高产栽培技术具有重要的现实意义。以连云区为例,重点对小麦绿色高产栽培关键技术要点展... 详细信息

传统栽培技术模式下,小麦产量与质量并不理想,导致种植效益较差,影响粮食安全稳定性,不利于小麦产业可持续发展,在此背景下,积极创新应用小麦绿色高产栽培技术具有重要的现实意义。以连云区为例,重点对小麦绿色高产栽培关键技术要点展开了研究。

关键词：小麦绿色高产栽培技术连云区

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高频低能冲击扰动下锚固结构渐进失效试验研究

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煤炭学报 2024年第1期49卷 309-319页

作者：张农王朋阚甲广许兴亮谢正正魏群中国矿业大学矿业工程学院江苏徐州221116 中国矿业大学煤炭精细勘探与智能开发全国重点实验室江苏徐州221116 徐州工程学院土木工程学院江苏徐州221116 江苏理工学院机械工程学院江苏常州213001

高频低能冲击扰动对巷道围岩及锚固结构造成持续疲劳损伤,是深部巷道趋向失稳的重要诱因,合理构建抗冲击动载巷道锚固支护体系及避免锚固结构失效已经成为深部煤炭开采面临的重要课题之一。采用理论分析、实验室试验、数值模拟等方法,... 详细信息

高频低能冲击扰动对巷道围岩及锚固结构造成持续疲劳损伤,是深部巷道趋向失稳的重要诱因,合理构建抗冲击动载巷道锚固支护体系及避免锚固结构失效已经成为深部煤炭开采面临的重要课题之一。采用理论分析、实验室试验、数值模拟等方法,研究了冲击载荷下锚固结构内部应力传递转化机制,阐明了锚固结构累积损伤与渐进失效机理,提出了冲击动载巷道控制准则。结果表明:压缩应力、拉伸应力与压拉快速转换形成的震荡效应是造成锚固结构损伤的三大要素;压缩、拉伸作用下介质抗压强度与不协调变形是导致锚固界面破坏的关键因素,锚固结构在内部法向驱动力作用下损伤累积,切线模量为负或单次动载冲击变形量持续逆势上扬时锚固结构失效,压缩、拉伸、震荡叠加影响下锚固结构预紧力损失及内部损伤存在明显的累积突变效应,内部裂隙以张拉裂隙为主,整体破坏从震荡效应向拉伸效应再向压缩破坏效应逐渐演化。通过提高围岩/锚固剂协调变形能力,增加锚固长度调动大范围岩体承载、保护锚固界面,保持锚固结构承载区抗剪阻滑强度大于动载冲击时内部法向驱动力,同时削弱震荡效应可有效降低锚固结构累积损伤程度。最后提出了降能-高阻-让压的冲击动载巷道控制技术准则,包括远场卸压、近场强支、破碎围岩改性、预紧力维持和让压结构,可为类似条件巷道维控提供指导。

关键词：冲击动载高频低能锚固结构累积损伤渐进失效

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Accelerating inverse crystal structure prediction by machine learning:A case study of carbon allotropes

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Frontiers of physics 2020年第6期15卷 97-103页

作者： Wen Tong qun wei Hai-Yan Yan Mei-Guang Zhang Xuan-Min Zhu School of Physics and Optoelectronic Engineering Xidian UniversityXi'an 710071China College of Chemistry and Chemical Engineering Baoji University of Arts and SciencesBaoji 721013China College of Physics and Optoelectronic Technology Baoji University of Arts and SciencesBaoji 721016China School of Information Guizhou University of Finance and EconomicsGuiyang 550025China

Based on structure prediction method,the machine learning method is used instead of the density functional theory(DFT)method to predict the material properties,thereby accelerating the material search process.In this paper,we established a data set of carbon materials by high-throughput calculation with available carbon structures obtained from the Samara Carbon Allotrope Database.We then trained a machine learning(ML)model that specifically predicts the elastic modulus(bulk modulus,shear modulus,and the Young's modulus)and confirmed that the accuracy is better than that of AFLOW-ML in predicting the elastic modulus of a carbon allotrope.We further combined our ML model with the CALYPSO code to search for new carbon structures with a high Young's modulus.A new carbon allotrope not included in the Samara Carbon Allotrope Database,named Cmcm-C24,which exhibits a hardness greater than 80 GPa,was firstly revealed.The Cmcm-C24 phase was identified as a semiconductor with a direct bandgap.The structural stability,elastic modulus,and electronic properties of the new carbon allotrope were systematically studied,and the obtained results demonstrate the feasibility of ML methods accelerating the material search process.

关键词： machine learning crystal structure prediction carbon

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