Four new orientation relationships of Mg_(17)Al_(12) phase with magnesium matrix in Mg-8Al-0.5Zn alloys

Although the non-basal precipitates, those not parallel to the basal plane, are more effective to block basal slip in Mg-Al alloys, the crystallographic orientation relationship(OR) between these precipitates and the α-Mg matrix has not been well established. In this work, the crystallography of the non-basal Mg_(17)Al_(12) precipitates in AZ80 alloy was systematically investigated by transmission electron microscopy(TEM). By tilting to a suitable electron beam direction, different kinds of non-basal precipitates were recognized in TEM, and the following four new ORs between the non-basal Mg_(17)Al_(12) precipitates and the matrix were revealed: ■, and ■.Furthermore, these ORs and their habit planes were explained using the edge-to-edge matching model. The findings in this work can provide some guidelines for designing the microstructure of Mg-Al alloys to enhance their precipitation hardening potential.

Morphology and orientation relationship of VC precipitates in HSLA steel

The morphology and distribution of VC precipitates in HSLA steel as well as the orientation relationship between VC precipitate and α-Fe were studied by transmission electron microscopy （TEM）. The chemical composition of the VC precipitate was analyzed qualitatively by using analytical electron microscopy （AEM） equipped with an energy dispersive spectrum （EDS） system. The VC precipitate is needle-like in shape with a size of about 10 nm in length and is homogeneously dispersed in the α-Fe matrix. The smaller lattice misfit along the 〈100〉 lattice direction of α-Fe matrix leads to VC precipitate forming with its long axes nearly parallel to the 〈100〉 lattice direction of α-Fe matrix. It is confirmed that the orientation relationship between VC precipitate and α- Fe is the ＂N-W＂ orientation relation by selected area electron diffraction （SAED） patterns.

TiN/γ-Fe interface orientation relationship and formation mechanism of TiN precipitates in Mn18Cr2 steel

A Mn18Cr2 steel containing TiN precipitates was fabricated by vacuum induction melting.The morphology of TiN precipitates and the interface orientation relationship between TiN and γ-Fe were characterized by means of SEM,TEM and SAED,and the formation mechanism of TiN precipitates in Mn18Cr2 steel was clarified.Results show that the TiN precipitates are more likely to exhibit a cubic-shaped morphology and form both within the grain and at the grain boundary of γ-Fe.The interface orientation relationship between TiN and γ-Fe is determined as follows:(100)_(TiN)//■_(γ-Fe),■_(TiN)//■_(γ-Fe).Because of the smallest interfacialmisfit,the secondary close-packed lane {100} of TiN preferentially combines with the close-packed plane {111} of γ-Fe during the precipitation in order to minimize the interface energy.After nucleation,the TiN precipitates exhibit cubic appearance due to the fact that the TiN has a FCC structure with rock salt type structure.This study provides reference for the material design of the austenitic high-manganese steels with excellent yield strength.

Special Orientation Relationships Observed at the Early Stages of Recrystallization in Pure AlMn Alloy

Electron Back Scattering Diffraction (EBSD) technique in a SEM was used to obtain local orientationalinformation on new grains and their surrounding deformed matrices at the early stages of recrystallization in pureA1-1 .3%Mn alloy. Results show that special orientation relationships including twin-relationship often exist betweennew grains, between new grains and deformed grains or between deformed grains. The occurrence of such specialorientation relationships is attributed to the special deformation behavior in the samples with large initial grain size.The formation of recrystallization twins is discussed in a different way to those of traditional ones.

Multiple eutectic orientation relationships in undercooled Ni-38wt.%Si eutectic alloy

Eutectic orientation relationships(EORs) in an undercooled Ni-38 wt.%Si alloy were analyzed by electron backscatter diffraction. A total of seven EORs were identified, and three of them were found at the under-cooling degree ?T≈31 K. It is found that their orientations of the primary NiSi phase are same but the misorientation between the neighboring NiSi2 grains can be either 50° or 60°. The multiple EORs were ascribed to a possible change in the growth direction of the primary phase, the change of the primary phase from the NiSi phase to the NiSi2 phase, and the transition from coupled to uncoupled eutectic growth. The current work shows that epitaxial growth of the second eutectic phase on the primary eutectic phase can obey either a single EOR or multiple EORs, which is a unique phenomenon.

Analysis of Orientation Relationships,Carbon Partitioning and Strengthening Mechanism of a Novel Ultrahigh Strength Steel

The orientation relationships,carbon partitioning and strengthening mechanism of a novel ultrahigh strength steel were analyzed in depth during the complex process of heat treatment.The experimental results reveal that the(011)α//()γ,[100]α//[011]γ orientation relationships can be drawn between martensite and retained austenite.The position and angle of martensite and retained austenite are shown more clearly from the stereographic projections.Moreover,the calculated results show that the carbon content near the austenite interface is the highest in the shorter carbon allocation time.With the further increase of time,its carbon content gradually decreases.Furthermore,a model of the relationship between yield strength and strengthening mechanism was established.It was proved that the main strengthening components contributing to the yield strength include Orowan strengthening,grain-size strengthening and dislocation hardening.The main strengthening mechanism of steel in this experiment is dislocation strengthening.

习近平新时代中国特色社会主义思想的世界观和方法论:辩证关系、核心要义与实践指向

把握好习近平新时代中国特色社会主义思想的世界观和方法论,要正确认识和处理世界观和方法论的关系、习近平新时代中国特色社会主义思想的世界观和方法论与马克思主义世界观和方法论的关系、与中华优秀传统文化的关系、与习近平新时代中国特色社会主义思想的关系。要从不同维度深刻领悟其核心要义,即必须坚持人民至上、必须坚持自信自立、必须坚持守正创新、必须坚持问题导向、必须坚持系统观念、必须坚持胸怀天下。习近平新时代中国特色社会主义思想的世界观和方法论具有强烈的实践指向性,要在学好用好马克思主义哲学的基础上,在“两个结合”中不断推进马克思主义中国化时代化,为新时代新征程推进中国式现代化提供行动指南。

主观规范与吸烟者戒烟行动计划:戒烟意向和关系导向特征的作用

考察吸烟主观规范和戒烟主观规范对戒烟行动计划的预测作用及戒烟意向的中介作用和关系导向特征的调节作用。对694名经常吸烟者进行问卷调查,结果表明:(1)吸烟者两种规范显著预测戒烟行动计划;(2)戒烟意向在两种规范与行动计划间起中介作用;(3)关系导向特征正向调节吸烟主观规范和戒烟意向的关系。结果说明,吸烟者两种规范对戒烟意向及戒烟行动计划的预测作用具有共存性及拮抗性,且关系导向特征增强吸烟主观规范的预测作用。

创新的新动力:智能时代人机关系驱动员工创新行为的影响研究

人工智能时代的到来使得人机关系表现出相互融合、相互协作的新形态,创新是企业经营和发展的重要源泉,企业应用智能机器协助工作对员工创新行为的影响则是当前组织行为学的一个重要研究点。文章基于资源保存理论和自我决定理论,通过引入中介变量学习目标导向和调节变量伦理氛围探究人机关系影响员工创新行为的路径。实证研究表明:人机关系正向影响员工的创新行为;学习目标导向中介人机关系与员工创新行为之间的关系;伦理氛围不仅可调节人机关系对学习目标导向的影响,还可调节学习目标导向的中介作用。根据上述研究结论,文章提出管理者应重视智能机器的引入对员工产生的影响,意识到学习目标导向的重要性,注重在企业中塑造良好的伦理氛围。

创造性与“新文科”的现代取向——以“第一轴心期”转向“第二轴心期”为背景

一般认为,大理科是以创造性为基本取向的学科,大文科则以秩序的供给呈现出保守的一面。其实这是一个误解。创造性是现代科学文化、人文文化与社会科学文化的共同特征。人文社会科学知识的刷新,也就是它的创造性,丝毫也不弱于大理科。从传统文化的“两创”扩展出来的新文科“两创”命题,促使人们意识到大文科在维护人文价值与创新知识体系上的双重责任。文科在目前大学体制中的被动处境,是文科新旧更替的现实动力。新文科需要以当下的“现代”品格确立其学科特性,以求新文科能够成功顺应科技革命掀起的知识变革大潮,让新文科能够重现“第一轴心期”的人文学辉煌,一改文科尾随理工科的颓势。为此,文科需要祛除“无用即大用”的自辩自限,以学科的跨越、知识的综合、当下“现代”呈现的“第二轴心期”的全新解释为取径,确立自己的宏大使命。新文科之“新”的根本含义即在于此。

Mg-Sn基合金沉淀强化研究进展

Mg-Sn基合金是应用前景广阔的时效强化型合金,添加合金元素可以细化Mg_(2)Sn沉淀相,并增强其时效强化效果,合金化元素选择及添加量是优化Mg-Sn合金力学性能的关键因素。本文总结了6种有理和9种无理的Mg_(2)Sn与Mg基体的取向关系,具有有理取向的Mg_(2)Sn沉淀位于基面呈板状和棒状,而无理取向的Mg_(2)Sn沉淀为非基面的板状和盘状。结合形貌和取向,进一步综述合金元素对Mg_(2)Sn沉淀相形核和生长的影响规律,其中Al、Zn元素促使非基面Mg_(2)Sn相析出;Ag、Na元素为Mg_(2)Sn相提供更多的形核位点;Ca和Y元素形成高熔点的三元相,时效效果不理想。基于研究现状,展望了Mg-Sn基合金研究趋势和方向。

树冠位置对香樟叶形态性状和异速生长关系的影响

为深入了解树冠位置对植物叶形态性状的影响,在常绿乔木香樟树冠上下2层和东南西北4个方位开展调查取样,系统分析了不同树冠位置间叶形态性状(叶长、叶宽、叶厚、叶柄长、叶柄直径和叶形指数)及其异速生长关系的差异性。结果表明,叶形态性状在不同树冠方位间均差异显著,但上下2层变化趋势不完全一致。在树冠上层,除叶形指数和叶炳长外,其余4个性状均表现为东侧最大。在树冠下层,除叶形指数外,其余5个性状指标均表现为东侧最小。在同一方位上,叶形态性状在上下2层间也存在一定差异,其中叶形指数多为下层高于上层,而其他形态性状多呈相反趋势。此外,树冠层次和方位的交互作用对叶片长、叶片厚、叶柄长和叶柄直径有显著影响。各层次和各方位叶形态性状间多为异速生长关系(即异速生长指数不等于1),且多无显著差异。在所有树冠层次和树冠方位,叶宽与叶厚、叶宽与叶炳长、叶长与叶厚及叶长与叶柄长之间均呈异速生长关系。可见,树冠位置对香樟叶形态性状的影响较大,但形态性状间的异速生长关系相对稳定,这是香樟叶形态性状表型可塑性和内在关系稳定性的重要体现。

新型城镇化、市场化改革与数字经济发展

随着中国正式迈入新发展阶段,高效推进新型城镇化建设,进一步加速数字经济发展,着力构建高水平现代化市场体系已然成为中国“十四五”时期乃至未来助力高质量发展的关键举措。基于中国30个省份2011-2020年的面板数据,综合运用面板向量自回归模型、耦合协调度模型、双重固定效应模型等方法客观揭示了新型城镇化、市场化改革与数字经济三大系统的互动关系、耦合协调发展程度及其有效驱动因素,得到以下研究结论:第一,新型城镇化能够显著推动地区市场化改革,市场化改革有利于促进数字经济发展;新型城镇化与数字经济则能够彼此支持、相互促进;第二,中国新型城镇化、市场化改革与数字经济的耦合协调程度稳步提升,三大系统间的互动联系愈发密切,协调发展态势已基本形成,但总体呈现由东向西的区域梯度差距分布;第三,固定资产投资、政府干预、科技创新等因素则是驱动三大系统耦合协调发展的关键。由此表明,创新完善宏观调控政策,科学引导,精准施策,统筹推动新型城镇化、市场化改革与数字经济的稳健发展,合理实现三者间的高水平联动,将是当代中国实现经济转型与高质量发展的题中应有之义。

中德两国数字教育平台建设目标定位探究——基于中德相关政策文本的目标模型构建与分析

教育数字化转型大势所趋下,中国和德国分别建立了国家级数字教育平台,即中国国家智慧教育公共服务平台和德国国家教育数字化平台。通过对两国相关政策文本进行三级编码分析,分别构建出各自的目标定位模型,并在此基础上展开比较分析与逻辑透视。分析结果表明,中德国家数字教育平台拥有共识性目标,具有对教育资源、教育质量的共同关切;但同时二者的定位取向和理性权衡存在着差异,德国国家数字化平台展现出循证取向和工具理性,中国国家智慧教育平台体现出理念取向和价值理性。不过殊途同归,中德国家数字教育平台的目标定位都理应回归本质,牢牢把握教育基本逻辑,建立和谐共生的人技关系,以维护人的主体性与发展性为轴心。

服务型与技术型职业院校发展状况比较研究:基于大语言模型

为深入探讨服务型职业院校与技术型职业院校在资源投入、参与教学改革以及助推企业发展三个关键方面的行业差异,为职业教育的精准发展提供理论支撑和实践指导,利用大语言模型ChatGPT,从职业院校发布的质量年度报告中抽取主谓宾结构信息,以此为基础构建本体关系的三元组,进而深入剖析服务型与技术型职业院校在资源投入、教学改革以及企业发展助推等三个维度上的具体差异。结果显示,服务型职业院校更注重服务类专业的实践教学和职业素养培养,致力于提升学生的服务能力和综合素质,以满足服务行业对人才的需求;而技术型职业院校则更侧重于技术类专业的教学设备、实训基地建设与技术更新,旨在培养具备专业技术能力和创新精神的技术人才。

他者性师生关系:内涵、特征与实践路径——基于他者伦理学的视角

师生关系是教育教学中最基本的一对关系,和谐稳定的师生关系有利于教育工作的顺利进行。基于他者伦理学提出的他者性师生关系是一种“我—他”关系、“非对称”关系以及伦理责任关系,其表现出的特征包括学生作为“绝对他者”具有“他异性”、教师作为“责任主体”具有“为他性”、师生交往的时间观念具有“异质性”。他者性师生关系的实践方略主要涵扩以下三个方面:一是从“为己”到“为他”,转变教师个人的主体观念;二是从“平等对话”到“伦理责任”,重塑师生之间的交往逻辑;三是从“素质关怀”到“人文关怀”,革新师生之间的交往模式。

基于产状Fisher分布的岩石节理最小样本容量确定方法

节理产状是影响岩体结构及其工程性质的关键参数之一,因此准确计算节理的平均产状是岩体工程性质研究的基础。由于节理产状的离散性,合理确定节理的最小样本容量对于计算节理组的平均产状具有重要意义。基于Fisher分布,阐释了节理产状随机数的生成方法,提出一种考虑“超越上半球投影产状”(OEBEUHP)的平均产状计算方法。随机生成不同数量、不同κ值的Fisher分布产状来研究节理样本容量对平均产状准确性的影响,在保证准确率不低于0.95的情况下,建立了最小样本容量与Fisher分布常数κ值的经验关系。研究结果表明:节理样本容量对平均产状的统计准确性影响显著,样本容量越大,平均产状的统计准确率越高;最小样本容量与κ值呈明显的反比例关系,反比例系数为1 007.23。通过对三峡地下厂房上游边墙和乌东德水电站平洞PD5-2节理的统计分析,验证了该经验关系的适用性,能够有效指导节理产状的采样工作。

铝单晶扭转变形行为及静态再结晶机理

对〈123〉取向铝单晶进行了不同应变量下常温单向扭转变形及后续退火处理,利用电子背散射衍射(EBSD)技术对退火前后试样进行了表征,分析了铝单晶不同应变量与退火条件下微观组织演变与静态再结晶行为。结果表明:铝单晶常温扭转变形过程中发生晶格旋转,其形变基体内部由平行于活化滑移平面{111}的变形微带组成。位错在扭转变形中形成并通过相互作用而导致位错堆积,从而诱发铝单晶晶格旋转和取向散射。退火温度为500℃时,晶界迁移速率增加,形变铝单晶中取向差在20°~45°高能晶界的二次再结晶晶粒优先生长,导致其晶粒尺寸持续增长至1 mm左右。随着应变量和退火温度的增加,再结晶晶粒由相邻形变基体围绕〈111〉、〈123〉和〈122〉方向旋转20°~60°形核产生,30°~50°〈111〉型取向关系逐渐占据主导地位。

需求导向下合肥市公园绿地空间布局研究

立足主体需求的视角,采用GIS空间分析方法,剖析合肥市公园绿地的分布格局特征,探究公园绿地空间配置水平。结果表明:研究区域内公园绿地总体呈现“核心-边缘”圈层式的空间分布格局,各类型公园的空间分布形态差异显著;整体上公园绿地表征为显著性聚类的空间聚集格局,其中居住区公园的聚集格局表现为显著聚类,综合公园和区域公园则为随机分布;研究区域内近30%的居住小区不在公园绿地的服务覆盖范围内,各类公园的覆盖范围存在较大差距;公园绿地同小区的平衡协调关系具有较强的空间异质性。通过探析公园绿地的空间布局特征,以期为同类型城市绿地系统规划提供支撑。

Revealing the phase-transformation path in a FeCoNiSnx eutectic high entropy alloy system by crystallographic orientation relationships

High entropy alloys are the focus of current research.An accurate description of their phase-transformation path,however,is a challenge when their phase constituent and transformation process are complex.In this study,a FeCoNiSn x eutectic high entropy alloy(EHEA)system was investigated and a novel FeCoNiSn EHEA composed of BCC+HCP phases was reported.The transition from the hypoeutectic to the fully eutectic and then to the hypereutectic microstructure with the Sn addition was characterized by the electron backscatter diffraction(EBSD)technology,and the phase-transformation path was clari-fied by crystallographic orientation relationships.The studies reveal that the primary phase of FeCoNiSn x(x=0.2,0.4)is FCC structure,and a further Sn addition induces an obvious phase-transformation from FCC to BCC in both the primary phase and eutectic lamellar,which satisfies the Kurdjumov-Sachs(K-S)or Nishiyama-Wasserman(N-W)variant orientation relationship.The mechanical results confirm that the phase structure and microstructure transition caused by Sn addition do significantly improve the strength and hardness of FeCoNiSn x EHEAs,but have serious adverse effects on plasticity.This study would be of significance to understanding the phase-transformation process in HEAs and preparing the HEAs with aimed mechanical properties.