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Microstructure Evolution and Mechanical Properties of Friction Stir Welded Al-Cu-Li Alloy

Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 855-871页

作者： Peng Chen Wenhao Chen Jiaxin Chen Zhiyu Chen yang Tang Ge Liu bensheng Huang Zhiqing Zhang School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China Sichuan Provincial Engineering Research Center of Advanced Materials Manufacturing Technology for Shale Gas High-Efficient Exploitation Southwest Petroleum UniversityChengdu 610500China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China School of Robot Engineering Yangtze Normal UniversityChongqing 408100China

The investigation concentrates on friction stir welded(FSW)Al-Cu-Li alloy concerning its local microstructural evolution and mechanical *** grain features were characterized by electron back scattered diffraction(EBSD)technology,while precipitate characterization was conducted by using transmission electron microscopy(TEM)aligned along[011]Al and[001]Al zone *** mechanical properties are evaluated through micro-hardness and tensile *** can be found that nugget zones exhibit finely equiaxed grains evolved through complete dynamic recrystallization(DRX),primarily occurring in continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX).In the thermal-mechanically affected zone(TMAZ),numerous sub-structured grains,exhibiting an elongated morphology,were created due to partial DRX,signifying the dominance of CDRX,DDRX,and geometric dynamic recrystallization(GDRX)in this region.T_(1)completely dissolves in the nugget zone(NZ)leading to the formation of Guinier-Preston zones and increase ofδ′,β′and S′.Conversely,T_(1)partially solubilizes in TMAZ,the lowest hardness zone(LHZ)and heat affected zone(HAZ),and the residual T_(1)undergoes marked coarsening,revealing various T_(1)*** solubilization and coarsening of T_(1)are primary contributors to the degradation of hardness and strength.θ′primarily dissolves and coarsens in NZ and TMAZ,whilst this precipitate largely coarsens in HAZ and LHZ.σ,TB,grain boundary phases(GBPs)and precipitate-free zone(PFZ)are newly generated during FSW.σexists in the TMAZ,LHZ and HAZ,whereas TB nucleates in *** and PFZ mostly develop in LHZ and HAZ,which can cause strain localization during tensile deformation,potentially leading to LHZ joint fracture.

关键词： Al-Cu-Li alloy Friction stir welding Microstructure evolution Mechanical properties

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A review on the transformation of birnessite in the environment:Implication for the stabilization of heavy metals

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Journal of Environmental Sciences 2024年第5期139卷 496-515页

作者： Miao Shi Qingzhu Li Qingwei Wang Xuelei Yan bensheng Li Linhai Feng Chao Wu Rongrong Qiu Hongkai Zhang Zhihui yang Weichun yang Qi Liao Liyuan Chai School of Metallurgy and Environment Central South UniversityChangsha 410083China National Engineering Research Centre for Control and Treatment ofHeavy Metal Pollution Central South UniversityChangsha 410083China Water Pollution Control Technology Key Lab of Hunan Province Changsha 410083China

Birnessite is ubiquitous in the natural environment where heavy metals are retained and easily *** surface properties and structure of birnessite change with the changes in external environmental conditions,which also affects the fate of heavy *** the effect and mechanism of the birnessite phase transition process on heavy metals is the key to taking effective measures to prevent and control heavy metal ***,the four transformation pathways of birnessite are summarized first in this ***,the relationship between transformation pathways and environmental conditions is *** relevant environmental conditions include abiotic(e.g.,co-existing ions,pH,oxygen pressure,temperature,electric field,light,aging,pressure)and biotic factors(e.g.,microorganisms,biomolecules).The phase transformation is achieved by the key intermediate of Mn(Ⅲ)through interlayer-condensation,folding,neutralizationdisproportionation,and dissolution-recrystallization *** AOS(average oxidation state)of Mn and interlayer spacing are closely correlated with the phase transformation of *** but not least,the mechanisms of heavy metals immobilization in the transformation process of birnessite are summed *** involve isomorphous substitution,redox,complexation,hydration/dehydration,*** transformation of birnessite and its implication on heavy metals will be helpful for understanding and predicting the behavior of heavy metals and the crucial phase of manganese oxides/hydroxides in natural and engineered environments.

关键词： Birnessite Transformation Heavy metals Pathways Mechanism

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In-building coverage of millimeter-wave wireless networks from channel measurement and modeling perspectives

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Science China(Information Sciences) 2020年第8期63卷 5-20页

作者： Peize ZHANG Cheng YI bensheng yang Cheng-Xiang WANG Haiming WANG Xiaohu YOU State Key Laboratory of Millimeter Waves Southeast University National Mobile Communications Research Laboratory Southeast University

To progress cost-effective deployment of millimeter-wave(mm Wave) wireless networks for indoor users, the prediction of indoor-to-indoor(I2I) and outdoor-to-indoor(O2I) coverage based on field measurement studies is of great interest to the future generation mobile communication system. First, measurements in I2I and O2I scenarios, which have advantages in terms of achieving a fair comparison of channel characteristics across different mm Wave bands and bandwidths, are performed. Next, the developed dual-slope path loss model with a break-point distance is found to well fit omnidirectional and directional measured I2I data, especially at 39.5 GHz, revealing that the transition from lit or shadow regions to totally blocked regions is abrupt. Combined with space-time propagation characteristics, the indoor blockage effect on path loss and angular spread is investigated, therein being essential for the design of beam-steering and tracking algorithms. Double-directional measurement results show that most dominant paths arrive along the line-ofsight path, and only a few in-building reflections can be detected in higher frequency bands. Based on the joint analysis of channel measurement and modeling results, several mm Wave network design and in-building coverage enhancement insights are presented.

关键词： building entry loss channel modeling in-building coverage millimeter-wave communication propagation measurements

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Progress of gaseous arsenic removal from flue gas by adsorption:Experimental and theoretical calculations

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Journal of Environmental Sciences 2024年第2期136卷 470-485页

作者： Xuelei Yan Qingzhu Li Xiaowei Huang bensheng Li Shengtu Li Qingwei Wang School of Metallurgy and Environment Central South UniversityChangsha 410083China National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution Central South UniversityChangsha 410083China National Engineering Research Center for Rare Earth Materials General Research Institute for Non-Ferrous MetalsBeijing 100088China

Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution *** mainly exists in the form of highly toxic As_(2)O_(3)in the flue ***,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution *** gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic *** the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in ***,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further *** on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic *** addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this ***,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.

关键词： Gaseous arsenic Flue gas Adsorption Theoretical calculation Mechanism

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Analysis of Maximum Liquid Carrying Capacity Based on Conventional Tubing Plunger Gas Lift

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Energy Engineering 2024年第6期121卷 1521-1533页

作者： Yanqun Yu Wenhao Xu Yahui Huangfu Jinhai Liu bensheng Wang Kai Liu College of Mechanical and Electronic Engineering China University of Petroleum(East China)Qingdao266580China Energy Technology&Services Oil Production Services Company CNOOCTianjin300450China

China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable productionof these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately graspthe drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift inthe plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellboreconfigurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculationmethod for the maximum daily fluid production rate based on the work regime with the highest fluid recovery ratewere determined. For the first time, the critical flow rate method was proposed as a constraint for the maximumliquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift withdifferent casing sizes were developed. The results showed that for 23/8 casing plunger-lift, with a well depth ofshallower than 808 m, the maximum drainage rate was 33 m3/d;for 27/8 casing plunger-lift, with a well depth ofshallower than 742 m, the maximum drainage rate was 50.15 m3/d;for 31/2 casing plunger-lift, with a well depthof shallower than 560 m, the maximum drainage rate was 75.14 m3/d. This research provides a foundation for thescientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonableplunger-lift work regimes.

关键词： Unconventional well conventional tubing string plunger gas lift critical flow rate liquid carry-over chart version

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Effects of a periodic intermittent theta burst stimulation in Alzheimer's disease

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General Psychiatry 2024年第1期37卷 53-63页

作者： Xingqi Wu Yibing Yan Panpan Hu Lu Wang Yue Wu Pan Wu Zhi Geng Guixian Xiao Shanshan Zhou Gongjun Ji bensheng Qiu Ling Wei yanghua Tian Hesheng Liu Kai Wang Department of Neurology First ffiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina School of Mental Health and Psychological Sciences Anhui Medical UniversityHefeiAnhuiChina Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders HefeiAnhuiChina Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health HefeiAnhuiChina Department of Psychology and Sleep Medicine The Second Affliated Hospital of Anhui Medical UniversityHefeiAnhuiChina Center for Biomedical Imaging University of Science and Technology of ChinaHefeiAnhuiChina institute of Artificial Intlligence Hefei Comprehensive National Science CenterHefeiAnhuiChina Department of Neuroscience Medical University of South CarolinaCharlestonSouth CarolinaUSA

Background Previous studies havedemonstrated that excitatory repetitive transcranial magnetic stimulation(rTMS)can improve the cognitive function of patients with Alzheimer's disease(AD).Intermittent theta burst stimulation(iTBS)is a novel excitatory rTMS protocol for brain activity stimulation with the ability to induce long-term potentiation-like plasticity and represents a promising treatment for ***,the long-term effects of iTBS on cognitive decline and brain structure in patients with AD *** We aimed to explore whether repeating accelerated iTBS every three months could slow down the cognitive decline in patients with *** In this randomised,assessor-blinded,controlled trial,iTBS was administered to the left dorsolateral prefrontal cortex(DLPFC)of 42 patients with AD for 14days every *** included the Montreal Cognitive Assessment(MoCA),a comprehensive neuropsychological battery,and the grey matter volume(GMV)of the *** were evaluated at baseline and after *** longitudinal pipeline of the Computational Anatomy Toolbox for SPM was used to detect significant treatment-related changes over *** The iTBS group maintained MoCA scores relative to the control group(t=3.26,p=0.013)and reduced hippocampal atrophy,which was significantly correlated with global degeneration scale *** baseline Mini-Mental State Examination(MMSE)score,apolipoprotein E genotype and Clinical Dementia Rating were indicative of MoCA scores at ***,the GMV of the left(t=0.08,p=0.996)and right(t=0.19,p=0.977)hippocampus were maintained in the active group but significantly declined in the control group(left:t=4.13,p<0.001;right:t=5.31,p<0.001).GMV change in the left(r=0.35,p=0.023)and right(r=0.36,p=0.021)hippocampus across the intervention positively correlated with MoCA changes;left hippocampal GMV change was negatively correlated with global degeneration scale(r=-0.32,p=0.041)*** D

关键词： stimulation Alzheimer maintained

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西部典型矿区弱胶结地层岩石的物理力学性能特征

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煤炭学报 2019年第3期44卷 865-873页

作者：孙利辉纪洪广杨本生河北工程大学矿业与测绘工程学院河北邯郸056038 北京科技大学土木与资源工程学院北京100083 河北省煤炭资源综合开发与利用协同创新中心河北邯郸056038

西部矿区弱胶结岩层与中东部矿区岩层力学性能之间的差别认识不清是导致西部矿区开采过程中灾害性事故频发的根本原因。通过现场调研、理论分析、实验室实验等方法,研究了我国煤矿区弱胶结地层地域分布规律,选取新疆矿区大井南一井和苇... 详细信息

西部矿区弱胶结岩层与中东部矿区岩层力学性能之间的差别认识不清是导致西部矿区开采过程中灾害性事故频发的根本原因。通过现场调研、理论分析、实验室实验等方法,研究了我国煤矿区弱胶结地层地域分布规律,选取新疆矿区大井南一井和苇子沟矿、鄂尔多斯矿区的营盘壕矿、大海则矿、陶忽图矿、高头窑矿等6对典型矿井岩石物理力学数据,分析了密度、孔隙率、含水率、弹性模量、抗压强度、抗拉强度、黏聚力、内摩擦角、泊松比等参数随埋深变化规律。现场采集了红庆河煤矿的砂质泥岩进行了崩解实验。研究结果表明:弱胶结地层主要分布在我国的新疆地区、鄂尔多斯盆地矿区、蒙东矿区,岩石成岩不充分,岩石强度普遍偏低,具有明显的松、散、弱的特性;西部矿区岩性主要为砂岩、砂质泥岩及泥岩,胶结物大多为泥质;岩石密度与埋深呈正相关,随埋深增加呈线性递增,岩石孔隙率、含水率与埋深呈负相关;岩石的弹性模量、抗压强度、抗拉强度、黏聚力随埋深增加具有一定的线性递增关系;岩石的泊松比、内摩擦角与埋深无明显的相关性;实验发现弱胶结岩石遇水后具有强烈的崩解性,循环次数越多,崩解后的粒径越小越均匀,弱胶结岩石的强崩解性是导致西部矿区采场导水裂隙带高度增大的主要因素;弱胶结岩石强度普遍低于中东部同类岩石强度;建立岩石物理力学性能集合可进一步明确中西部岩石间差别。

关键词：西部矿区保水采煤弱胶结岩石物理力学性能煤系地层

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深部巷道薄厚组合壳支护适用性模拟分析

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煤矿安全 2022年第7期53卷 189-194,200页

作者：孙利辉宋家乐贺庆丰丁斌彭世龙熊怀鑫杨贤达杨本生河北工程大学矿业与测绘工程学院河北邯郸056038 矿山地质灾害成灾机理与防控重点实验室陕西西安710054 河北省煤炭资源综合开发与利用协同创新中心河北邯郸056038

深部巷道在高应力作用下出现大变形,传统锚杆支护技术难以控制巷道围岩稳定。以羊东矿埋深1000 m的回风大巷为工程背景,实测了原岩应力,分析了原岩应力与回风大巷之间的关系;研发了深部巷道薄厚组合壳支护结构,采用数值模拟方法分析了... 详细信息

深部巷道在高应力作用下出现大变形,传统锚杆支护技术难以控制巷道围岩稳定。以羊东矿埋深1000 m的回风大巷为工程背景,实测了原岩应力,分析了原岩应力与回风大巷之间的关系;研发了深部巷道薄厚组合壳支护结构,采用数值模拟方法分析了不同侧压系数下巷道薄厚组合壳的适用性。结果表明:现场最大主应力为水平主应力,平均为27.97 MPa,侧压系数在1.23~1.42之间,最大水平主应力与回风大巷夹角为68°,属于大角度斜交,巷道局部易出现破坏;综合分析围岩变形破坏、支护体受力等指标,千米埋深下侧压系数在0.5~2.0之间时,巷道薄厚组合壳支护结构能够有效控制巷道稳定;侧压系数大于2时,则需要提高薄壳刚度、锚注强度,方能满足控制巷道稳定的要求。

关键词：深部巷道高应力场波纹钢板侧压系数薄厚组合壳支护

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深井软岩巷道连续“双壳”治理底鼓机理与技术

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采矿与安全工程学报 2014年第4期31卷 587-592页

作者：杨本生高斌孙利辉杨万斌河北工程大学资源学院河北省资源勘测研究重点实验室河北省煤炭矿井建设工程技术研究中心河北邯郸056038 河北工程大学土木工程学院河北邯郸056038

底鼓治理是巷道支护的难题之一,亦是巷道支护的重点和关键。根据新景矿中条带轨道巷现场调查和监测,分析了深井工程软岩巷道底鼓影响因素和机理分析。分析认为底鼓主要是巷道底板处于无支护状态下首先发生剪切破坏,而后由于水理作用导... 详细信息

底鼓治理是巷道支护的难题之一,亦是巷道支护的重点和关键。根据新景矿中条带轨道巷现场调查和监测,分析了深井工程软岩巷道底鼓影响因素和机理分析。分析认为底鼓主要是巷道底板处于无支护状态下首先发生剪切破坏,而后由于水理作用导致岩层进一步破碎和挤压流动。应用连续"双壳"支护理论,分析了连续"双壳"治理底鼓机理,构建了"底板浅孔注浆(浅部壳体)+深部锚索束高压注浆(深部壳体)"的连续"双壳"治理底鼓技术,取得良好效果。

关键词：深井巷道工程软岩底鼓治理连续“双壳” 支护机理

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强动压松软煤层巷道煤帮变形破坏特征及锚注加固试验研究

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采矿与安全工程学报 2019年第2期36卷 232-239页

作者：孙利辉杨贤达张海洋李星杨本生河北工程大学矿业与测绘工程学院河北邯郸056038 河北省资源勘测研究重点实验室河北邯郸056038 河北省煤炭资源综合开发与利用协同创新中心河北邯郸056038 冀中能源邯郸矿业集团有限公司河北邯郸056002 中国平安财产保险股份有限公司内蒙古分公司内蒙古呼和浩特010010

松软煤层巷道受动压影响巷帮强烈变形破坏,传统支护难以保证巷道服役期内正常使用。以云驾岭煤矿1213工作面回风巷受动压扰动巷帮大变形问题为例,分析巷帮强烈变形破坏特征,研究巷帮滑移变形机理,提出巷帮锚注加固技术。结果表明:煤体... 详细信息

松软煤层巷道受动压影响巷帮强烈变形破坏,传统支护难以保证巷道服役期内正常使用。以云驾岭煤矿1213工作面回风巷受动压扰动巷帮大变形问题为例,分析巷帮强烈变形破坏特征,研究巷帮滑移变形机理,提出巷帮锚注加固技术。结果表明:煤体强度低、巷道轴向与最大水平主应力近似垂直、强烈的动压扰动、巷帮支护系统与煤体强度不耦合、侧向支承压力等是导致巷帮大变形的主要原因;受开采扰动作用巷帮产生滑移破坏,使高帮侧部分锚杆支护失效,增加了巷帮灾害发生危险;巷帮注浆提高了破碎煤体的完整性和承载能力,帮锚索将浅部潜在破坏煤体与深部稳定煤体锚固在一起限制巷帮变形。现场试验及矿压监测表明:巷道煤帮总体变形仅为224mm,保证了巷道服役期内正常使用。该巷帮治理技术适用于动压影响下的松软煤巷巷帮加固。

关键词：开采扰动松软煤层巷帮大变形锚注滑移变形

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