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室温和深冷轧制对纯Al再结晶{111}/{111}近奇异晶界的影响

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金属学报 2024年

作者：李振想王卫国 gregory s rohrer 洪丽华陈松林燕周邦新福建理工大学材料科学与工程学院福建理工大学晶界工程研究所上海大学材料研究所 Department of Material science and Engineering Carnegie Mellon University

{111}/{111}近奇异晶界比一般晶界更耐蚀，研究此类晶界的形成条件、影响因素和生成机制，设法调控此类晶界并提高其比例是改善相关铝合金晶界腐蚀性能的根本途径。为了解铝合金生成{111}/{111}近奇异晶界的本征行为，本工作选择高纯Al ... 详细信息

{111}/{111}近奇异晶界比一般晶界更耐蚀，研究此类晶界的形成条件、影响因素和生成机制，设法调控此类晶界并提高其比例是改善相关铝合金晶界腐蚀性能的根本途径。为了解铝合金生成{111}/{111}近奇异晶界的本征行为，本工作选择高纯Al (99.99%)为实验材料，首先经室温反复多向锻造和370℃再结晶退火获得晶粒尺寸均匀、平均晶粒尺寸约为20μm且晶粒取向随机分布的组织均匀化初始样品；再将初始样品分别在室温(25℃)和-196℃深冷进行厚度减缩量为80%的轧制变形，及370℃、30 min再结晶退火处理。采用EBsD和基于五参数分析的晶界界面匹配定量表征方法对两样品进行测试和分析。结果表明，经-196℃深冷轧制并再结晶的样品，其{111}/{111}近奇异晶界比例达到6.0%，相比室温轧制并再结晶的样品提升了120%。XRD、EBsD及硬度结果表明，经室温和-196℃深冷轧制的样品中均形成了较强的{011}形变织构；较比室温轧制，经-196℃深冷轧制的样品内残余压应力更大，晶粒碎化更严重、储能更高。在后续370℃退火过程中，经室温和-196℃深冷轧制的样品，其再结晶机制均以{011}取向生长为主；较比于室温轧制，经-196℃深冷轧制的样品可提供更大的晶界迁移驱动力，其样品再结晶组织的平均晶粒尺寸更大且{011}再结晶织构更强。统计结果表明，{011}取向晶粒与其他取向的晶粒毗连所形成的晶界中存在较高比例的{111}/{111}近奇异晶界；同时，为{011}取向晶粒与其相邻的且具有{011}漫散取向的晶粒间也形成较多的{111}/{111}近奇异晶界，这是导致经-196℃深冷轧制及再结晶的样品中{111}/{111}近奇异晶界比例较高的主要原因。

关键词：高纯Al 深冷轧制近奇异晶界晶界界面匹配择尤取向

不同温度轧制Al-Zn-Mg-Cu合金再结晶后的{111}/{111}近奇异晶界

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金属学报 2023年第7期59卷 947-960页

作者：王宗谱王卫国 gregory s rohrer 陈松洪丽华林燕冯小铮任帅周邦新福建工程学院晶界工程研究所福州350118 福建工程学院材料科学与工程学院福州350118 Department of Materials science and Engineering Carnegie Mellon UniversityPittsburghPA15213-3890USA 上海大学材料研究所上海200072

经470~520℃双级固溶处理的国产Al-Zn-Mg-Cu (7A85)合金分别在250、300、350、400和450℃施行厚度减缩量为80%的轧制变形后,立即经520℃、30 min完成再结晶退火处理。采用基于电子背散射衍射和五参数分析的晶界界面匹配表征方法对上述... 详细信息

经470~520℃双级固溶处理的国产Al-Zn-Mg-Cu (7A85)合金分别在250、300、350、400和450℃施行厚度减缩量为80%的轧制变形后,立即经520℃、30 min完成再结晶退火处理。采用基于电子背散射衍射和五参数分析的晶界界面匹配表征方法对上述试样进行测试和分析发现,轧制温度对后续再结晶退火{111}/{111}近奇异晶界的形成有显著影响,表现为{111}/{111}近奇异晶界比例随轧制温度的升高呈现先上升、然后下降至一定值并保持基本恒定的变化规律;经300℃轧制及后续再结晶退火,{111}/{111}近奇异晶界比例达到极大值5.0%,是奇异晶界(共格孪晶界)比例的近10倍。对试样显微组织进行观察和分析表明,经300℃轧制,样品中形成特定变形亚结构,并且具备一定形变储能,在后续再结晶退火过程中,其组织演化以连续再结晶为主,有利于{111}/{111}近奇异晶界的形成。相反,经350℃及以上温度轧制,试样发生了不连续动态再结晶,不利于后续退火{111}/{111}近奇异晶界的形成;经250℃轧制,试样内存在较高储能,在后续退火过程中发生了不连续再结晶,也不利于{111}/{111}近奇异晶界的形成。离线原位表面侵蚀实验和高分辨透射电子显微镜观察表明,{111}/{111}近奇异晶界的腐蚀抗力显著高于一般晶界,此类晶界具有旋错结构特征,其结构有序度显著高于一般晶界。

关键词： Al-Zn-Mg-Cu合金超高强铝合金近奇异晶界晶界界面匹配晶界腐蚀

高温压缩变形Al-Zn-Mg-Cu合金动态再结晶后的{111}/{111}近奇异晶界

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金属学报 2023年

作者：刘光辉王卫国 gregory s rohrer 陈松林燕童芳冯小铮周邦新福建理工大学晶界工程研究所 Department of Materials science and Engineering Carnegie Mellon University 福建理工大学材料科学与工程学院上海大学材料研究所

将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 s-1、真应变为1.20的压缩变形，压缩后立即水冷。采用电子背散射衍射和基于五参数分析的晶界界面匹配定量表征方法对... 详细信息

将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 s-1、真应变为1.20的压缩变形，压缩后立即水冷。采用电子背散射衍射和基于五参数分析的晶界界面匹配定量表征方法对上述3个样品的显微组织和晶界特征分布进行观察分析。结果表明，高温压缩后的显微组织不均匀，存在间隔分明的细晶组织和粗晶组织，其中细晶组织中的晶界以小角度晶界(LAGB)为主，粗晶组织中的晶界以大角度晶界(HAGB)为主；粗、细晶组织中的{111}/{111}近奇异晶界({111}/{111}-NsB)比例均随压缩温度的升高而增大，其中经520℃压缩的试样，其LAGB中的{111}/{111}-NsB占总晶界的比例为8.77%,HAGB中的{111}/{111}-NsB占总晶界的比例为4.53%。进一步考察各试样的应力-应变曲线以及450℃压缩30%时的显微组织特征可见，应变介于0.05～0.70为稳态流变阶段，主要发生初次动态再结晶(DRX)，其主要由粗晶及其HAGB构成。应变介于0.70～1.20为二次硬化阶段，主要发生二次DRX，其中不连续DRX(DDRX)和连续DRX(CDRX)同时进行，且优先发生在某些微区；不论是DDRX因形核和核心长大生成的HAGB，还是CDRX因亚晶合并引入的LAGB，均使对应微区的晶粒细化，导致样品总体流变应力急剧上升。二次DRX阶段，CDRX行为随压缩温度的提高而增强，{111}/{111}-NsB比例也随之增加，特别是LAGB中的{111}/{111}-NsB比例快速增加。

关键词： Al-Zn-Mg-Cu合金近奇异晶界晶界界面匹配连续动态再结晶

轧制变形及再结晶00Cr12铁素体不锈钢中的{011}/{011}近奇异晶界

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中国科学：技术科学 2024年第3期54卷 459-476页

作者：黄新宇王卫国 rohrer gregory s 徐刚陈松冯小铮张厚安陈文哲周邦新福建理工大学晶界工程研究所福州350118 福建理工大学材料科学与工程学院福州350118 Department of Materials science and Engineering Carnegie Mellon UniversityPittsburgh 15213-3890USA 厦门理工学院材料科学与工程学院厦门361024 上海大学材料研究所上海200072

不同于低层错能面心立方结构的奥氏体不锈钢,高层错能体心立方结构的铁素体不锈钢在形变及再结晶等组织重构过程中很难形成结构稳定且十分耐蚀的奇异晶界(共格孪晶界).研究{011}/{011}近奇异晶界的影响因素和形成机理,将有可能为改善铁... 详细信息

不同于低层错能面心立方结构的奥氏体不锈钢,高层错能体心立方结构的铁素体不锈钢在形变及再结晶等组织重构过程中很难形成结构稳定且十分耐蚀的奇异晶界(共格孪晶界).研究{011}/{011}近奇异晶界的影响因素和形成机理,将有可能为改善铁素体不锈钢,特别是低Cr铁素体不锈钢晶间腐蚀性能提供晶界工程新思路.本文选用经固溶处理和组织均匀化处理的00Cr12低Cr铁素体不锈钢为实验材料,5个平行试样分别在350℃,500℃,580℃,650℃和690℃进行厚度减缩量为70%的单向轧制变形后,立即进行750℃、2 h再结晶退火处理.使用基于电子背散射衍射和五参数分析的晶界界面匹配表征方法对上述样品进行测试和分析发现,轧制温度对00Cr12铁素体不锈钢再结晶{011}/{011}近奇异晶界比例有显著影响,再结晶后的{011}/{011}近奇异晶界比例随再结晶退火前轧制温度的升高先上升再下降,其中经650℃轧制的样品,其再结晶后{011}/{011}近奇异晶界比例达到极大值6.82%.取向分布函数(ODF)和重叠极图晶界迹线分析表明,经650℃轧制的样品,其再结晶组织中形成了强的{011}织构;具有{011}及其漫散取向的晶粒之间较多地存在/θ取向差关系(θ为绕的旋转角),其关联晶界为{011}/{011}近奇异晶界,这是经650℃轧制的样品,其再结晶后{011}/{011}近奇异晶界比例达到极大值的原因.离线原位表面侵蚀实验表明,{011}/{011}近奇异晶界的腐蚀抗力显著高于一般晶界.因此,基于本文研究结果,进一步调控并提高{011}/{011}近奇异晶界的比例将有助于从根本上显著改善00Cr12铁素体不锈钢晶间腐蚀性能.

关键词： 00Cr12铁素体不锈钢近奇异晶界晶界界面匹配晶间腐蚀

High Temperature Iron Ethylene Polymerization Catalysts Bearing N,N,N'-2-(1-(2,4-Dibenzhydryl-6-fluorophenylimino)ethyl)-6-(1-(arylphenylimino)ethyl)pyridines

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Chinese Journal of Polymer science 2024年第2期42卷 188-201,I0007页

作者： Chantsalnyam Bariashir Qiu-Yue Zhang Bayasgalan Ulambayar gregory A.solan Tong-Ling Liang Wen-Hua sun Institute of Chemistry and Chemical Technology Mongolian Academy of SciencesUlaanbaatar13330Mongolia Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular science Institute of ChemistryChinese Academy of SciencesBeijing100190China Department of Chemistry University of LeicesterUniversity RoadLeicesterLE17RHUK state Key Laboratory for Oxo synthesis and selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

The N,N,N'-ferrous chloride complexes,[2-{CMeN(2,4-(CHPh)_(2)-6-FC_(6)H_(2))}-6-(CMeNAr)C_(5)H_(3)N]FeCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3) Fe1,2,6-Et_(2)C_(6)H_(3)Fe2,2,6-^(i)Pr_(2)C_(6)H_(3) Fe3,2,4,6-Me_(3)C_(6)H_(2) Fe4 and 2,6-Et_(2)-4-MeC_(6)H_(2) Fe5),each possessing one N-2,4-dibenzhydryl-6-fluorophenyl group,were readily synthesized from their respective unsymmetrical bis(imino)pyridines,*** identification of Fe2 highlighted the variation in the steric properties provided by the dissimilar N-aryl *** pre-treatment with either MAO or MMAO,complexes Fe1-Fe5 all displayed,at an operating temperature of 80℃,high activities for ethylene polymerization with levels falling in the order:Fe4> Fe1> Fe5> Fe2> ***,Fe4/MAO displayed the highest activity of 1.94×10^(7) g_(PE)·mol_(Fe)^(-1)·h^(-1) of the study with only a modest loss in performance at 90℃.Generally,the resulting polyethylenes were highly linear(T_(m) range:122-132℃),narrowly disperse and of low molecular weight(M_(w) range:6.73-46.04kg·mol^(-1)),with the most sterically hindered Fe3 forming the highest molecular weight polymer of the ***-group analysis by ^(1)H-and ^(13)CNMR spectroscopy revealed saturated alkyl(n-propyl and i-propyl) and unsaturated vinyl chain ends indicative of the role of both β-H elimination and chain transfer to aluminum as termination *** comparison with previou sly reported iron precatalysts with similar tridentate ligand skeletons,it is evident that the introduction of a large benzhydryl group in combination with a fluorine as the ortho-substituents of one N-aryl group has the effect of enhancing thermal stability of the iron polymerization catalyst whilst maintaining appreciable polymer molecular weight.

关键词： Iron catalyst Ethylene polymerization Linear polyethylene Fluoride effect Thermal stability

Criteria for selecting Carbon subsurface and Ocean storage site in Developing Countries: A Review

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American Journal of Climate Change 2024年第2期13卷 103-139页

作者： gregory Mwenketishi Hadj Benkreira Nejat Rahmanian school of Engineering Faculty of Engineering and Digital Technologies University of Bradford Bradford UK

Important first phases in the process of implementing CO2 subsurface and ocean storage projects include selecting of best possible location(s) for CO2 storage, and site selection evaluation. sites must fulfill a number of criteria that boil down to the following basics: they must be able to accept the desired volume of CO2 at the rate at which it is supplied from the CO2 source(s);they must as well be safe and reliable;and must comply with regulatory and other societal requirements. They also must have at least public acceptance and be based on sound financial analysis. site geology;hydrogeological, pressure, and geothermal regimes;land features;location, climate, access, etc. can all be refined from these basic criteria. In addition to aiding in site selection, site characterization is essential for other purposes, such as foreseeing the fate and impacts of the injected CO2, and informing subsequent phases of site development, including design, permitting, operation, monitoring, and eventual abandonment. According to data from the IEA, in 2022, emissions from Africa and Asias emerging markets and developing economies, excluding Chinas, increased by 4.2%, which is equivalent to 206 million tonnes of CO2 and were higher than those from developed economies. Coal-fired power generation was responsible for more than half of the rise in emissions that were recorded in the region. The difficulty of achieving sustainable socio-economic progress in the developing countries is entwined with the work of reducing CO2 emissions, which is a demanding project for the economy. Organisations from developing countries, such as Bangladesh, Cameroon, India, and Nigeria, have formed partnerships with organisations in other countries for lessons learned and investment within the climate change arena. The basaltic rocks, coal seams, depleted oil and gas reservoirs, soils, deep saline aquifers, and sedimentary basins that developing countries (Bangladesh, Cameroon, India, and Nigeria etc.

关键词： Aquifer CCUs site selection Carbon Dioxide Capture and storage (CCs) CO2 sequestration CCs Governmental Regulation CO2 Environment Impact Geological storage

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science Bulletin 2024年第7期69卷 850-852页

作者：周晓东 gregory Y.H.Lip 郑明华 Department of Cardiovascular Medicine the Heart Centerthe First Affiliated Hospital of Wenzhou Medical UniversityWenzhou 325000China Liverpool Centre for Cardiovascular science at University of Liverpool Liverpool John Moores University and Liverpool Heart&Chest HospitalLiverpool L693BXUK Department of Clinical Medicine Aalborg UniversityAalborg 9000Denmark MAFLD Research Center Department of Hepatologythe First Affiliated Hospital of Wenzhou Medical UniversityWenzhou 325000China Institute of Hepatology Wenzhou Medical UniversityWenzhou 325000China Key Laboratory of Diagnosis and Treatment for the Development of Chronic Liver Disease in Zhejiang Province Wenzhou 325000China

Heart failure with preserved ejection fraction(HFpEF)has an estimated incidence rate of approximately 27 cases per 10,000 person-year[1].Furthermore,the prevalence of HFpEF is on the rise and is expected to exceed that of heart failure with reduced ejection fraction(HFr EF)[2].In the near future,HFpEF is expected to become the predominant subtype of heart failure[2].

关键词： predominant fraction 射血分数保留型

Vaginal Birth after Cesarean after Zavanelli Maneuver: A Woman’s Right to Choose

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Open Journal of Obstetrics and Gynecology 2024年第7期14卷 1091-1095页

作者： Nicole Jenkins gregory Vurture Jonathan D. Baum Department of Obstetrics and Gynecology Jersey Shore University Medical Center Neptune NJ USA

Introduction: Vaginal birth after cesarean (VBAC) plays an essential role in lowering cesarean rates. Despite endorsement, trial of labor after cesarean (TOLAC) attempt rates remain low, in part due to fear of lawsuits. Zavanelli maneuver is a last resort procedure in the management of shoulder dystocia. We discuss a case of a woman determined to have a vaginal birth after her prior birth was complicated by shoulder dystocia requiring a Zavanelli maneuver. Her physicians were reluctant to allow her a TOLAC given her prior obstetric history. Case: A 34-year-old para 1 with prior cesarean delivery due to shoulder dystocia that required Zavanelli maneuver presents determined to pursue VBAC in her current pregnancy. she considered her delivery route options and addressed her modifiable risk factors. she consulted with multiple perinatologists who agreed that a TOLAC was reasonable, however she had to travel more than 70 miles (from Pennsylvania to New Jersey) to find an obstetrical practice and hospital willing to consider VBAC. she transferred care and the remainder of her prenatal course was uncomplicated. she went into labor at 41 weeks and had a successful VBAC without complication. In a thank you letter to her obstetrician, she described her birth experience as euphoric. Conclusion: This case illustrates how a woman’s choice of delivery route may be impacted by fear of litigation. Local providers focused on her prior delivery instead of her overall improved risk profile. Delivery route decisions should be based on a thorough evaluation of all risk factors and individualized to meet the reproductive goals of each woman. .

关键词： Vaginal Birth after Cesarean Zavanelli Autonomy Case Report

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有向图上的一些猜想和开放问题

数学进展 2024年第1期53卷 1-12页

作者：艾江东 gregory GUTIN 史永堂 Ander YEO 南开大学数学科学学院核心数学与组合数学教育部重点实验室天津300371 伦敦大学皇家霍洛威学院计算机科学系英国萨里郡TW200EX 南开大学组合数学中心核心数学与组合数学教育部重点实验室天津300371 南丹麦大学数学与计算机科学系丹麦欧登塞M区DK-5230 约翰内斯堡大学数学与应用数学系南非约翰内斯堡2006

讨论了有向图上的几个猜想和开放问题.一些尚未解决的问题是新的.

关键词：有向图出度圈路分划最大有向割集拟核 seymour二次邻域猜想无圈2-染色