Giant Volume Magnetostriction Caused by Itinerant Electron Metamagnetic Transition and Pronounced Invar Effects in La(Fe_xSi_(1-x))_(13) Compounds

A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.

Critical behavior in the itinerant ferromagnet SmMn_(2)Ge_(2)

Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple magnetic phases.The critical behavior of the ferromagnetic phase transition is investigated by employing the modified Arrott plot with the Kouvel-Fisher method.The critical temperature TCis determined to be around 342.7 K with critical exponents ofβ=0.417 andγ=1.122,and the interaction function is found to be J(r)~r^(-4.68),suggesting the coexistence of long-range and shortrange magnetic interactions.Our results contribute to the understanding of complex magnetism in Sm Mn_(2)Ge_(2),which may provide fundamental guidance in future spintronic applications.

CrAlGe:An itinerant ferromagnet with strong tunability by heat treatment

We present a comprehensive investigation on CrAlGe and realize that it is an itinerant ferromagnet with strong tunability of the Curie temperature T_(C)and the spontaneous momentμ_(0)depending on annealing heat treatment.While the value of T_(C) was previously reported to be 80 K withμ_(0)≈0.41μB,in this work the two quantities attain values as high as 170 K and 0.66μ_(B),respectively.Heat treatment does not cause changes of the lattice parameters and symmetry,but results in a slight narrowing of the Bragg peaks.The strong tunability of the itinerant ferromagnetism indicates significantly tunable hybridization between the Cr 3d electrons and the conduction bands,in agreement with the dominant Cr–Al/Ge bonds of this compound.Further tuning along the same line towards even stronger or weaker itinerant ferromagnetism promises an interesting follow-up to clarify the localized-itinerant duality of the 3d electrons in this compound.

Itinerant Topological Magnons in SU (2) Symmetric Topological Hubbard Models with Nearly Flat Electronic Bands

We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly flat electronic bands,on a Kagome lattice,is considered as the prototype.This model exhibits ferromagnetic order when the lowest electronic band is half-filled.Using the numerical exact diagonalization method with a projection onto this nearly flat band,we can obtain the magnonic spectra.In the flat-band limit,the spectra exhibit distinct dispersions with Dirac points,similar to those of free electrons with isotropic hoppings,or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry.Significantly,the non-flatness of the electronic band may induce a topological gap at the Dirac points,leading to a magnonic band with a nonzero Chern number.More intriguingly,this magnonic Chern number changes its sign when the topological index of the electronic band is reversed,suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band.Our work suggests interesting directions for the further exploration of,and searches for,itinerant topological magnons.

Resistance Anomaly and Linear Magnetoresistance in Thin Flakes of Itinerant Ferromagnet Fe_(3)GeTe_(2)

Research interests in recent years have expanded into quantum materials that display novel magnetism incorporating strong correlations,topological effects,and dimensional crossovers.Fe_(3)GeTe_(2)represents such a twodimensional van der Waals platform exhibiting itinerant ferromagnetism with many intriguing properties.Up to date,most electronic transport studies on Fe_(3)GeTe_(2)have been limited to its anomalous Hall responses while the longitudinal counterpart(such as magnetoresistance)remains largely unexplored.Here,we report a few unusual transport behaviors on thin flakes of Fe_(3)GeTe_(2).Upon cooling to the base temperature,the sample develops a resistivity upturn that shows a crossover from a marginally-ln T to a-T^(1/2)dependence,followed by a lowertemperature deviation.Moreover,we observe a negative and non-saturating linear magnetoresistance when the magnetization is parallel or antiparallel to the external magnetic field.The slope of the linear magnetoresistance also shows a nonmonotonic temperature dependence.We deduce an anomalous contribution to the magnetoresistance at low temperatures with a scaling function proportional-HT^(1/2),as well as a temperature-independent linear term.Possible mechanisms that could account for our observations are discussed.

Quality of life and influencing factors between local and itinerant populations during the COVID-19 pandemic

Objective:To determine the difference in quality of life and its influencing factors between local and itinerant populations in Nanjing during COVID-19.Methods:The quality of life questionnaire,which was based on the Brief Scale of WHO Quality of Life and redesigned by the research group,was used to randomly investigate 1150 people in 5 districts of Nanjing.Results:A total of 1112 valid questionnaires were collected(local population,n=558;itinerant population,n=554).The quality of life of the itinerant population was significantly lower than the local population.The itinerant population scores in physiology,psychology,social relationships,and environment were lower than the local population(all P values<0.05).COVID-19 had a greater impact on the itinerant population than on the local population,especially in medical assistance,enjoyment of life,and interpersonal relationships(all P values<0.05).Conclusion:The itinerant population had a lower quality of life than that of the local population during the prevention and control pandemic of COVID-19,thus more social support and help is warranted.

Around China in 80 Days (Ⅲ) On the road with itinerant Americans

ＡｒｏｕｎｄＣｈｉｎａｉｎ８０Ｄａｙｓ（Ⅲ）ＯｎｔｈｅｒｏａｄｗｉｔｈｉｔｉｎｅｒａｎｔＡｍｅｒｉｃａｎｓＢｙＢＩＬＬＢＲＯＷＮＮＥＡＲｄｕｓｋｗｅｓｉｄｌｅｄｕｐａｌｏｎｇｓｉｄｅａＴｉｂｅｔａｎｃｏｎｖｏｙａｎｄｐｒｅｐａｒｅｄｔｏｂｅｄｄｏｗｎ...

Stories of Itinerant Workers in Beijing

IANGXiangfenisacheerful19-year-oldpeasantgirl.Sheiscontentwithherlife,andfeelsasthoughshehasbeenlivingunderaluckystareversinceshegraduatedfromjuniormiddleschool.ShecomesfromasmallvillageinShandongProvince.HerwholefamilystilllivesinShandong,butWangnow...

基于场动力理论的巡回指导教师专业发展机制研究

巡回指导教师是特殊教育学校教师角色变革与转型的重要产物,对其专业发展的关注是推动我国融合教育高质量发展的必然要求。基于场动力理论,采用主题分析法,深描巡回指导教师专业发展的困境、动力与路径,构建其专业发展机制的逻辑解释框架。研究结果表明,巡回指导教师数量少,在专业发展中面临融合教育理念推进困难、外部教育环境复杂、多重角色冲突难协调等困境。因此,巡回指导教师需要形成基于职业认同、自我效能感及专业发展意愿的内生动力,并在外界环境的支持下,通过自主学习和反思、积极参与科研与实践形成专业发展的内部通路;通过积极接受培训、参与专业发展共同体等实践活动,形成专业发展的外部通路,进而实现其可持续发展。

创建“枫桥式人民法庭”的路径探析

新时代“枫桥经验”被赋予了鲜明的时代特征,即“矛盾不上交、平安不出事、服务不缺位”。作为司法审判系统的末梢,人民法庭处在司法服务群众的最前沿,在践行“枫桥经验”中尚存在诸多问题,主要表现为诉源治理工作开展不够深入、非诉讼纠纷化解资源分散、统一协作机制运行不畅、缺乏长效制度机制及经费保障、参与基层社会治理的边界存在模糊地带等。究其根源,主要是部分人民法庭运用“枫桥经验”开展工作的观念意识、路径方法没有与时俱进所致。为更好地发挥人民法庭厚植党的执政根基、能动司法为民服务的作用,应转变司法服务理念,坚持源头预防为先、非诉机制挺前,不断完善矛盾纠纷多元化解工作机制。

Gate-tunable Berry curvature in van der Waals itinerant ferromagnetic Cr_(7)Te_(8)

The anomalous Hall effect(AHE)that associated with the Berry curvature of occupied electronic states in momentum-space is one of the intriguing aspects in condensed matter physics,and provides an alternative for potential applications in topological electronics.Previous experiments reported the tunable Berry curvature and the resulting magnetization switching process in the AHE based on strain engineering or chemical doping.However,the AHE modulation by these strategies are usually irreversible,making it difficult to realize switchable control of the AHE and the resultant spintronic applications.Here,we demonstrated the switchable control of the Berry-curvature-related AHE by electrical gating in itinerant ferromagnetic Cr_(7)Te_(8)with excellent ambient stability.The gate-tunable sign reversal of the AHE can be attributed to the redistribution of the Berry curvature in the band structure of Cr_(7)Te_(8)due to the intercalation-induced change in the Fermi level.Our work facilitates the applications of magnetic switchable devices based on gate-tunable Berry curvature.

革新意识与思想觉醒——俄国巡回展览画派的早期实践活动与审美图景

俄国19世纪最大的民主艺术协会——巡回展览协会(画派),成立于1870年,一直存续至1923年,由坚持现实主义原则的俄国画家群体创立,在俄国艺术史上打开了一个前所未有的崭新局面,让俄国艺术在此历史时期迸发出蓬勃的生命力。巡回展览画派诞生的前身和最初形态由“十四人反叛”事件开始,这群皇家美术学院的优等生们在艺术创作的反思和觉醒中奋起,从早期以“合作社”互助的形式凝聚到后来转变和发展为以画派协会的机制运转,期间进行了不同形式和规模的组织实践尝试。巡回展览画派作为艺术团体,它的运作模式、创作的革新意识和美学思想在不断探索的过程中逐渐形成了独特的实践路径和审美图景,串联起一条具备非凡内涵的发展脉络。

近代中国民营图书流通事业论略——以平教会与华洋义赈会巡回文库为例

近代中国巡回文库多由图书馆、学校教育部门或民教馆等公立事业单位举办,但社会力量与民间组织也参与了巡回文库事业建设。民营巡回文库种类因地而异,作为公共巡回文库,平教会巡回文库始终致力于民众教育与公共服务建设。作为服务于各地合作社员的文库,华洋义赈会合作巡回书库则立意于合作教育与农事知识普及。由于合作社员大多为基层民众且人数甚多,合作巡回书库兼具公共性与专业性双重服务属性。

上海市闵行区颛桥社区巡回医疗门诊药品利用和可及性分析

目的回顾性分析上海市闵行区颛桥社区2019~2022年巡回医疗门诊患者处方数据,评价历年巡回医疗门诊药品利用及常用药品可及性情况,以进一步满足社区患病人群用药需求,提升家庭医生团队服务能力。方法通过闵行区颛桥社区医疗卫生信息系统,提取并分析2019~2022年巡回医疗门诊患者医保类型、疾病分布、药品费用、用药种类、用药频度等数据。结果2019~2021年,闵行颛桥社区巡回医疗处方数量占总处方30%以上;2022年因新冠疫情影响,和2021年相比,占比下降40.84%。2019~2022年,门诊处方次均药费区间155.36~178.54元;高血压、冠心病、糖尿病、睡眠障碍等慢病占总就诊人次49%以上;2019~2022年比较,医保类型(含普通医保、其他居民、医疗互助帮困、无保老人、其他类型)处方人次构成比(χ^(2)=1881.168,P=0.000)、疾病类型(高血压、冠心病、糖尿病、睡眠障碍、其他疾病)处方人次构成比(χ^(2)=3255.282,P=0.000)差异有统计学意义。颛桥社区巡回医疗门诊患者疾病构成比在不断变化;单品种金额排序前10位药品品种、DDDs排序前10位药品品种处于不断变化之中。2019年,单品种DDDs排序前10位药品中,DDC值区间0.33~2.93元,2020年为0.26~2.93元,2021年和2022年均小于6.0元。结论巡回医疗门诊患者的用药需求和社区药品供给在不断调整变化,但巡回医疗已成为社区患者重要就诊方式。新服务模式有利于居民和家庭医生保持长期签约服务关系,有利于慢病健康管理,在实践中显示积极作用。颛桥社区巡回医疗门诊4年来的药品DDC值维持较低水平,人民群众的药品可及性得到提升。

随班就读巡回指导工作现状及反思:巡回指导教师的视角

研究从三个地区20名视障儿童巡回指导教师的视角,对随班就读巡回指导工作现状进行全面深入的解读;探讨巡回指导工作开展的重点与难点。在教师对自身工作反思与建议的基础上,概括出目前随班就读巡回指导工作的主要问题是:巡回指导制度不完善导致教师内部动机不足,相应支持缺乏,工作全面但不深入。研究从加强巡回指导制度建设,提高观念意识,深入挖掘巡回指导工作内涵,以及巡回指导教师培养四个方面提出了相应建议。

计量保障现状及发展趋势

分析了当前计量保障的多元化需求,介绍了计量保障现状及国内外最新研究动态,剖析了不同计量保障方式的特点,预测了未来计量保障的多元化发展趋势。

浅谈为基层部队卫生装备巡检巡修的做法和体会

基层部队卫生装备由于使用不当、部件磨损、老化等方面的原因,不可避免地会出现故障,需要靠维修来恢复装备原有的性能。合理地维修不仅能延长装备的使用寿命,还能减少和降低医疗事故的发生。

流动穆斯林城市社会适应性实证研究——以兰州市回族、东乡族为例

本文以兰州市流动穆斯林为例,在因子分析的基础上探讨流动穆斯林城市社会适应性现状及影响因素,结论如下:流动穆斯林城市社会适应性综合水平很低,"自我认同"因子最低,"城市归宿"次之,"身份判断"最高;流动穆斯林城市社会适应性有明显个体差异,文化程度和家庭月经济收入对其有明显正向促进作用,职业的影响不显著,年龄的影响出现波动现象;民族因素及文化认同是影响流动穆斯林城市社会适应性的深层次因素。

脑科学中若干非线性动力学问题

对近年发展起来的脑科学中的非线性问题作一介绍。这些问题得到脑科学界的广泛注意。它们是同步,混沌与混沌周游,噪声与随机共振。在很多不同背景下的神经生理实验表明脑皮层的振荡活动都存在同步与去同步现象。混沌在人与动物的脑中扮演着重要的角色,混沌周游与Freeman模型被认为与联想记忆或记忆的动态连接有关。适当噪声强度导致信噪比的极大提高——随机共振是脑神经系统能检测到极其微弱信号的工作机制。噪声也导致同步态并使之稳定。此外,噪声的一些其他作用也在本文中提及。

结构变迁理论视角下的流动穆斯林城市适应的障碍性因素分析——以兰州市回族、东乡族为例

随着城市化进程的加快,越来越多的少数民族人口进入城市,尤其是大城市。这一群体在接受"城市化"和"现代化"洗礼的过程中,相对于一般的进城务工人员,由于加入了民族意识、民族宗教习俗、民族价值文化等因素,从而使其城市适应变得更加复杂和艰难。本研究从社会结构变迁的角度出发,以兰州市流动穆斯林社会调查为基础,对影响流动穆斯林城市适应的障碍性因素(民族因素、自身因素、社会环境因素和制度因素)进行了深入、细致的分析;并阐述了流动穆斯林城市适应的关键障碍因素:地理距离、经济条件及心理文化。随着城市化进程的进一步加快,与以往的农民工城市适应的关键障碍因素不同,制度因素已不再是阻碍流动穆斯林城市适应最主要的因素,而是呈现出多元化的特点。