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低碳钢在NaNO3溶液中的应力腐蚀开裂

中国腐蚀与防护学报 1987年第1期 73-76页

作者：赵克清 w.dahl 西德阿亨大学冶金所鞍钢钢研所

对碳钢和低合金钢,特别是一系列高强钢构件,除用作与硝酸盐直接接触的化工设备外,用于氮肥厂的钢结构、混凝土中的钢筋,地下管道以及高温热风炉等都观察到过由硝酸盐引起的应力腐蚀开裂。过去人们主要用恒载荷法或恒变形法在较高温度(9... 详细信息

对碳钢和低合金钢,特别是一系列高强钢构件,除用作与硝酸盐直接接触的化工设备外,用于氮肥厂的钢结构、混凝土中的钢筋,地下管道以及高温热风炉等都观察到过由硝酸盐引起的应力腐蚀开裂。过去人们主要用恒载荷法或恒变形法在较高温度(90℃到沸点)和较高浓度的硝酸盐介质中研究各种因素对低合金钢或碳钢应力腐蚀开裂的影响。近来发现,在室温和含较低浓度NO的介质中,即使碳钢或低合金钢所受的机械应力低于屈服点也会出现应力腐蚀,并且在硝酸盐介质中除恒载荷条件下能产生应力腐蚀外,还会产生与应变率有关的应力腐蚀,它不存在阳极极化临界电位。由于以往的工作或者没有采用恒电位控制,

关键词：应力腐蚀开裂断面收缩率延伸率 NaNO3 自然腐蚀电位碳素钢低碳钢

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钢水喷镁精炼及其对钢性能的影响

工程科学学报 1983年第3期 1-35页

作者：赵凤林,T.EI.Gammal,w.dahl 北京钢铁学院冶金系西德阿亨大学冶金所西德阿亨大学冶金所博士教授所长教授

由于镁对钢的脱氧、脱硫、净化钢水及转变夹杂物形态的良好作用,近年来许多冶金工作者致力于加镁精炼钢水的研究工作,但因在冶金温度下镁的蒸汽压很高,而其在钢水的溶解度又极小,加入困难,这方面的研究多归于失败。本文利用阿亨大学热... 详细信息

由于镁对钢的脱氧、脱硫、净化钢水及转变夹杂物形态的良好作用,近年来许多冶金工作者致力于加镁精炼钢水的研究工作,但因在冶金温度下镁的蒸汽压很高,而其在钢水的溶解度又极小,加入困难,这方面的研究多归于失败。本文利用阿亨大学热力学数据库计算了以氩作为载气喷镁的脱氧、脱硫作用,以及压力和氩量对其影响,通过实验制定了行之有效的喷吹工艺,选择了合适的控制参数。在1-3大压下,氩量为0.1-0.3N.L/m:n,可以向钢水成功地喷入镁。经过镁精炼的钢水,氧含量可降至4ppm,硫含量降至10ppm,氧化物及硫化物的评级均为0级,其尺寸均在5μm之下。随着喷镁量的增加(钢水重量的0.062至％0.56％),夹杂物中镁的氧化物及硫化物量增加,夹杂物总量减少且呈球形,此种夹杂物在热形变中不变形。因此在通常材料中所存在的各向异性完全消失,特别是缺口冲击韧性横向性能值提高了2～3倍。文章对材料在不同温度下的冲击韧性、过渡温度及断口夹杂物的形态进行了研究和论述。

关键词：镁精炼镁处理夹杂物钢中硫化物夹杂缺口冲击韧性硫化锰硫化物热力学数据库硫含量钢水熔融金属

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氢对纯铁屈服行为的影响

金属学报 1987年第5期 437-440页

作者：隗学礼 J.Felefli w.dahl K.w.Lange 中国科学院金属研究所西德Aachen工业大学

一、引言 Fe和钢中加入氢会导致其力学性能特别是屈服行为明显的变化.Cracknell等把充氢后屈服台阶的消失归于氢在微孔洞中聚集,形成高压,并导致局部屈服.然而Vaughen等

关键词：屈服行为纯铁工业铁充氢塑性变形预变形

Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8页

作者： wéi wú Zhihui Luo Dao-Xin Yao Meng wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: while the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. we propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo

Citrobacter Causing Septic Arthritis: A Case Report

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Infectious Diseases & Immunity 2024年第3期4卷 146-148页

作者： Kimberly K.Levine Mary dahl Abubakar Tauseef Joseph Thirumalareddy Department of Internal Medicine Creighton University School of MedicineOmaha 68124NEUSA

The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and *** Citrobacter infections are infrequently diagnosed in environmental contexts,the rising incidence of nosocomial manifestations underscores the importance of considering this organism in the differential diagnosis of hospital-acquired *** present a case of patient with septic arthritis of the shoulder who had been originally admitted for the management of acute-on-chronic congestive heart failure exacerbation and severe *** hospital day 1,joint aspiration cultures and Gram stain confirmed the presence of Citrobacter koseri,a pathogen not commonly associated with septic arthritis,and ceftriaxone was administered to target *** hospital day 7,antibiotic was transitioned to levofloxacin,every other day for 4 *** patient was discharged to an acute rehabilitation facility after a 14-day hospital *** case stresses the importance of maintaining a broad differential diagnosis for any patients who present with fever and joint inflammation or swelling,especially in a postoperative setting.

关键词： Citrobacter koseri Bacteremia Septic arthritis

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Pervasive Attentive Neural Network for Intelligent Image Classification Based on N-CDE’s

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Computers, Materials & Continua 2024年第4期79卷 1137-1156页

作者： Anas w.Abulfaraj Department of Information Systems Faculty of Computing and Information TechnologyKing Abdulaziz UniversityRabigh21911Saudi Arabia

The utilization of visual attention enhances the performance of image classification *** attentionbased models have demonstrated notable performance,but many of these models exhibit reduced accuracy when confronted with inter-class and intra-class similarities and ***-Controlled Differential Equations(N-CDE’s)and Neural Ordinary Differential Equations(NODE’s)are extensively utilized within this ***’s possesses the capacity to effectively illustrate both inter-class and intra-class similarities and differences with enhanced *** this end,an attentive neural network has been proposed to generate attention maps,which uses two different types of N-CDE’s,one for adopting hidden layers and the other to generate attention *** distinct attention techniques are implemented including time-wise attention,also referred to as bottom N-CDE’s;and element-wise attention,called topN-CDE’***,a trainingmethodology is proposed to guarantee that the training problem is sufficiently *** classification tasks including fine-grained visual classification andmulti-label classification,are utilized to evaluate the *** proposedmethodology is employed on five publicly available datasets,including CUB-200-2011,ImageNet-1K,PASCAL VOC 2007,PASCAL VOC 2012,and MS *** obtained visualizations have demonstrated that N-CDE’s are better appropriate for attention-based activities in comparison to conventional NODE’s.

关键词： Differential equations neural-controlled DE image classification attention maps N-CDE’s

The quasi-Gramian solution of a non-commutative extension of the higher-order nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第3期76卷 51-61页

作者： H w A Riaz J Lin Department of Physics Zhejiang Normal UniversityJinhua 321004China

The nonlinear Schr?dinger(NLS)equation,which incorporates higher-order dispersive terms,is widely employed in the theoretical analysis of various physical *** this study,we explore the non-commutative extension of the higher-order NLS *** treat real or complex-valued functions,such as g_(1)=g_(1)(x,t)and g_(2)=g_(2)(x,t)as non-commutative,and employ the Lax pair associated with the evolution equation,as in the commutation *** derive the quasi-Gramian solution of the system by employing a binary Darboux *** soliton solutions are presented explicitly within the framework of *** visually understand the dynamics and solutions in the given example,we also provide simulations illustrating the associated ***,the solution can be used to study the stability of plane waves and to understand the generation of periodic patterns within the context of modulational instability.

关键词： integrable systems Darboux transformation solitons

Recent Advances in the Synthesis and Polymerization of New CO_(2)-Based Cyclic

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Chinese Journal of Chemistry 2024年第4期42卷 430-443页

作者： Matteo Lanzi Arjan w.Kleij Institute of Chemical Research of Catalonia(ICIQ) The Barcelona Institute of Science and Technology(BIST)Av.Països Catalans 1643007 TarragonaSpain Catalan Institute of Research and Advanced Studies(ICREA) Pg.Lluís Companys 2308010 BarcelonaSpain

Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates,whose recent reactivity has been expanded towards the formation of tailor-made engineering *** minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO_(2)based *** addition,their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring-opening of the carbonate *** perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO_(2).

关键词： Carbon dioxide Cyclic carbonates Functional macromolecules Heterocycles Polycarbonates Recycling Ring opening polymerization