Observation of Quantum Anomalous Hall Effect and Exchange Interaction in Topological Insulator/Antiferromagnet Heterostructure

Integration of a quantum anomalous Hall insulator with a magnetically ordered material provides an additional degree of freedom through which the resulting exotic quantum states can be controlled. Here, an experimental observation is reported of the quantum anomalous Hall effect in a magnetically-doped topological insulator grown on the antiferromagnetic insulator Cr₂O₃. The exchange coupling between the two materials is investigated using field-cooling-dependent magnetometry and polarized neutron reflectometry. Both techniques reveal strong interfacial interaction between the antiferromagnetic order of the Cr₂O₃ and the magnetic topological insulator, manifested as an exchange bias when the sample is field-cooled under an out-of-plane magnetic field, and an exchange spring-like magnetic depth profile when the system is magnetized within the film plane. These results identify antiferromagnetic insulators as suitable candidates for the manipulation of magnetic and topological order in topological insulator films.     

分解信号为正交本征模态函数的方法

利用快速滤波建立了一种对信号进行本征模态函数分解的全新方法。该方法与筛选方法相比较,具有操作简单,运算速度快,尤其适用于长信号的本征模态分解。该方法的另一个重要特点是分解所得各本征模态函数及非模态函数是严格正交的,不会产生模态混淆。     

Multifunctional Electrospun Nanofibers for Enhancing Localized Cancer Treatment

Localized cancer treatment is one of the most effective strategies in clinical destruction of solid tumors at early stages as it can minimize the side effects of cancer therapeutics. Electrospun nanofibers have been demonstrated as a promising implantable platform in localized cancer treatment, enabling the on‐site delivery of therapeutic components and minimizing side effects to normal tissues. This Review discusses the recent cutting‐edge research with regard to electrospun nanofibers used for various therapeutic approaches, including gene therapy, chemotherapy, photodynamic therapy, thermal therapy, and combination therapy, in enhancing localized cancer treatment. Furthermore, it extensively analyzes the current challenges and potential breakthroughs in utilizing this novel platform for clinical transition in localized cancer treatment.     

Localized surface plasmons of a single ambichiral nanostructure

Localized surface plasmons (SPs) of single ambichiral nanostructures (ACNs) were investigated using the discrete-dipole approximation. The extinction, absorption cross sections, and local electric filed magnitudes of a single ACN were calculated and compared with those obtained from the single chiral nanostructure (CN) as reference structure. The results showed that two localized SP peaks appear in ACN, while exist only one peak in CN. We found that the optical properties of ACNs are same as CN at low angular displacements, where the morphology of ACNs is closed to CN.     

非晶态合金的局域剪切变形与断裂机制

从自由体积模型、绝热剪切模型、位错模型及力学模型等方面全面综述了非晶态合金的局域剪切变形与断裂机制,提出了“自由体积＋绝热升温”模型并解释了合金的变形与断裂过程,最后简要讨论了该领域目前存在的问题及今后的发展趋势。     

形变诱发纳米晶局域固态非晶化的研究进展

形变诱发纳米晶金属材料局域固态非晶化转变是近年来提出的获得局域固态非晶化组织的一种新途径,这种转变机制使得以位错、变形孪晶、晶界滑动和晶粒转动为主要变形机制的纳米晶材料中可能存在一种全新的塑性变形机制,并且,局域固态非晶化的临界转变条件和转变机制可为材料的结构优化设计提供依据。概括了国内外实验及数值模拟手段关于形变诱发局域固态非晶化转变的研究,例如采用机械球磨、高压扭转变形、经典力场和分子动力学等方法,证明了形变诱发局域固态非晶化转变的存在。此外,还分析了发生局域固态非晶化转变的内在机制。基于晶体相场模型的优势,提出用该方法模拟局域固态非晶化转变的突出之处,表明了晶体相场法能够有效研究局域固态非晶化转变过程。     

过渡金属氮化物TinNm小团簇结构中的定域键

Ti、N形成的小团簇TinNm,当n＋m≤4时,一般出现线形和平面构型;当n＋m=5或6时,TinNm团簇异构体既有线形结构,也有平面结构,还有少数立体结构。线形结构大多形成强弱交替的定域键。平面结构中Ti—N键,随着原子数的增加,逐渐从共价键向离子键过渡,Ti失去电子增多,N得到电子也增多。而立体构型中大多形成离域键,验证了Anderson理论。     

焊接接头局部腐蚀的研究进展

因焊接接头局部腐蚀而造成的装置、设备和构件的失效事故屡见不鲜,造成了重大的经济损失甚至人身伤亡。然而迄今为止,对焊接接头局部腐蚀的行为、过程和机制的认识仍然比较有限。对国内外在焊接接头局部腐蚀的主要类型、研究方法、常见工程材料焊接接头的局部腐蚀行为以及腐蚀控制技术等方面的研究现状及主要进展做了详细介绍,最后对焊接接头局部腐蚀研究的发展方向进行了展望。     

Asymmetries influence on critical curves of the synthetic antiferromagnetic structures in magnetic random access memory

The influence of various physical parameters on magnetizations processes of two interacting ferromagnetic particles with significance for synthetic antiferromagnetic structures as a component of the magnetic random access memory are presented. Because the real structures are not perfectly symmetric, the alterations of the perfect structure reflected in magnetization processes especially on critical curves are analyzed. The effects of the coupling constant, magnetostatic interactions and anisotropy are also analyzed.     

用于HIT太阳能电池的本征非晶硅薄膜

带本征薄层的异质结（HIT）太阳能电池要求本征非晶硅薄膜具有生长速率低，暗电导大，光学带隙宽的特点。采用等离子增强化学气相沉积（PECVD）制备符合HIT太阳能电池要求的本征非晶硅薄膜，并通过分析薄膜的透射光谱，采用Tauc法计算了薄膜的光学带隙，为约1．87eV，衬底温度为180℃，放电功率为80W时获得的薄膜性能最佳。     

局域表面等离子体共振效应气体传感器的研究进展

贵金属纳米结构的局域表面等离子体共振光学在光催化、光学传感器、表面增强光谱学、太阳能电池等领域具有广阔的应用前景。基于贵金属的局域表面等离子体共振效应传感器的性能主要依赖于贵金属的结构,总结了纳米贵金属粒子性质以及各种结构的制备方法和应用,并展望了未来表面等离子体共振效应传感器的发展趋势。     

工人冒险作业时的内在心理结构研究

采用逆转理论及访谈方法，研究发现：煤矿工人在冒险作业时，其内在的心理结构深受文化程度、事故记录的影响。一般来说，文化程度高、非事故组的煤矿工人大都倾向于具有正面的元动机特征（ 内在心理结构） ，如唤醒回避、超前计划、尝试完成活动、服从规章制度及关心他人等，而工龄、工种、用工形式及年龄却很少发生影响     

新型铝锂合金的微观组织及其在局部腐蚀中的作用

新型铝锂合金由于其低密度、高比强度、高比刚度、高弹性模量、高损伤容限等优良性能日益广泛地应用于航空航天领域。然而,由于特殊的微观组织以及锂元素极高的化学活性,新型铝锂合金容易发生局部腐蚀,严重影响合金构件的使用寿命和安全可靠性。对新型铝锂合金的微观组织及其在合金腐蚀过程中的作用研究进展进行了综述,以期为新型铝锂合金的研究与应用提供一定参考。     

氧化锌中的本征点缺陷对材料光电性能的影响

ZnO薄膜中的本征点缺陷对材料的电学、发光性能有着至关重要的影响.目前,对本征点缺陷的研究是ZnO领域的一大热点,也是实现ZnO基光电器件的关键技术之一.本文结合最新研究,扼要综述了本征点缺陷的电荷特性、对本征ZnO为n型的作用机理、对p型ZnO制备的影响及点缺陷对薄膜绿光发光的贡献.     

第二相在铝合金局部腐蚀中的作用机制

铝合金中通常含有一些时效析出相及杂质相等第二相粒子,这些第二相粒子对铝合金局部腐蚀行为产生重大影响.概括了析出相θ(Al2Cu)、η(MgZn2)、β(Mg3Al2)及含Fe杂质相FeAl3等在铝合金局部腐蚀中的作用机制,重点介绍了S相(Al 2CuMg)和T1相(Al2CuLi)对铝合金局部腐蚀作用机制的不同观点.     

Static hole in a two-dimensional antiferromagnet

The energetics of static hole in a 2D antiferromagnetic (AF) is studied. AF is described by magnon operators in the LSW approximation, while the holes by fermionic operators. The energy spectrum of the magnons in the presence of the hole is determined from the perturbed Green’s function.     

聚琥珀酰亚胺的合成及特性黏数的测定

以马来酸酐为原料,合成了高分子量的聚琥珀酰亚胺。通过傅立叶变换红外光谱表征,表明分子中具有五元环酰亚胺结构,推断了反应机理。经热失重-差热分析,可知聚琥珀酰亚胺分解温度在387℃。用极限黏度法测定了聚琥珀酰亚胺分子量(因聚琥珀酰亚胺对毛细管壁的吸附,用常规测试处理的方法难以得到)。文中分别对流出时间t及溶液密度ρ进行校正,得到较好的测试结果,测得分子量为11110,比文献报道的高。     

Intrinsic Conductance of Domain Walls in BiFeO3

Ferroelectric domain walls exhibit a number of new functionalities that are not present in their host material. One of these functional characteristics is electrical conductivity that may lead to future device applications. Although progress has been made, the intrinsic conductivity of BiFeO₃ domain walls is still elusive. Here, the intrinsic conductivity of 71° and 109° domain walls is reported by probing the local conductance over a cross section of the BiFeO₃/TbScO₃ (001) heterostructure. Through a combination of conductive atomic force microscopy, high‐resolution electron energy loss spectroscopy, and phase‐field simulations, it is found that the 71° domain wall has an inherently charged nature, while the 109° domain wall is close to neutral. Hence, the intrinsic conductivity of the 71° domain walls is an order of magnitude larger than that of the 109° domain walls associated with bound‐charge‐induced bandgap lowering. Furthermore, the interaction of adjacent 71° domain walls and domain wall curvature leads to a variation of the charge distribution inside the walls, and causes a discontinuity of potential in the [110]_p direction, which results in an alternative conductivity of the neighboring 71° domain walls, and a low conductivity of the 71° domain walls when measurement is taken from the film top surface.     

Reusable Localized Surface Plasmon Sensors Based on Ultrastable Nanostructures

Nanoparticle arrays created by nanosphere lithography are widely used in sensing applications since their localized surface plasmon resonances are extremely sensitive to changes in the local dielectric environment. A major drawback for any biologically oriented sensing application of conventionally produced particle arrays is the lack of stability of the nanoparticles in aqueous media and buffer solutions. Here, a robust and reusable nanoscale sensing platform based on localized surface plasmon resonances of gold nanoparticles embedded in a silicon dioxide matrix is presented. The architecture exhibits extremely high stability in aqueous environments and can be regenerated several times by simple mechanical cleaning of the surface. The platforms surface is ultraflat by design, thus making it an ideal substrate for any bio‐oriented sensing application.