Weak Delocalization in Graphene on a Ferromagnetic Insulating Film

Graphene has been predicted to develop a magnetic moment by proximity effect when placed on a ferromagnetic film, a promise that could open exciting possibilities in the fields of spintronics and magnetic data recording. In this work, the interplay between the magnetoresistance of graphene and the magnetization of an underlying ferromagnetic insulating film is studied in detail. A clear correlation between both magnitudes is observed but through a careful modeling of the magnetization and the weak localization measurements, that such correspondence can be explained by the effects of the magnetic stray fields arising from the ferromagnetic insulator is found. The results emphasize the complexity arising at the interface between magnetic and 2D materials.     

Al2O3–CaO macroporous ceramics containing hydrocalumite-like phases

A mechanism to explain the lower onset strengthening temperature induced by CaCO₃ in alumina-based macroporous ceramics is proposed, which relies on hydrocalumite-like phase formation during processing. Close to 600 °C, such phases are decomposed to lime and mayenite (12CaO·7Al₂O₃), where the latter, due to its intrinsic nanoporosity and high thermal reactivity, generates bonds between the ceramic particles at ∼700 °C, resulting in microstructure strengthening. Based on this premise, the authors concluded that other Ca²⁺ sources could act similarly. Indeed, compositions containing Ca(OH)₂ or CaO showed the same effect on the onset strengthening temperature, which reinforces the proposed mechanism. The results attained indicated that macroporous insulators could be thermally treated at lower temperatures, just to acquire enough mechanical strength for installation, finishing in-situ their firing process. Besides that, lower sintering temperatures could be used to produce macroporous ceramics that would be applied in low thermal demand environments, e.g. aluminum industries.     

温度、湿度和风速对红外检测绝缘子的影响分析

为研究温度、湿度和风速对红外成像法检测绝缘子的影响,提高绝缘子红外检测的准确性,以110 kV绝缘子串为例,采用有限元分析方法研究温度、湿度和风速对均匀污秽和非均匀污秽条件下绝缘子串温度分布的影响。仿真表明:相同条件下,均匀污秽绝缘子温度略高于非均匀污秽绝缘子温度;温度对绝缘子红外检测影响较小;相对环境湿度显著影响绝缘子温度分布,湿度越低,越不利于检测,容易造成误检,其中相对湿度80%时,零值绝缘子容易被检测;风速对绝缘子温度分布影响较大,风速越大,对绝缘子温度分布影响越大,因此,对绝缘子进行红外检测时,风速不宜大于4 m/s。仿真结果可用于指导电网红外巡检工作,保障绝缘子红外巡检结果的准确性,从而实现电网的安全稳定运行。     

Motion-based method for estimating time required to attach self-adhesive insulators

A self-adhesive insulator is a component of a home appliance that is used to suppress vibration or prevent humidity affecting the internal parts of the appliance. There is a wide range of types and designs available, allowing them to be applied to areas having different shapes. At the design stage, once an insulator design has been developed sufficiently to identify its dimensions and features, the attaching time and baseline cost must be estimated with reasonable accuracy to enable a comparison of vendor quotes. However, the current estimation method is not sufficiently accurate in terms of the baseline cost. This paper presents a motion-based time-estimating scheme with which the time required for the attachment of such insulators can be calculated more accurately. The scheme has been developed by analyzing the motions needed to attach 350 insulators and then designating representative motions and their time values. For this purpose, a modular arrangement of predetermined time standards (MODAPTS) is adopted. Motion-based time-estimation method is useful in terms of simplicity and accuracy. It enables design engineers to estimate the time required for the attachment based only on a drawing of the insulator and a few MODAPTS rules. Estimates made with this method should vary from the actual value by no more than 9.5%.     

Effect of MgO Addition on the Bondability and Interfacial Reaction between Dielectric and Glass-Ceramics for the Fabrication of Multi-Component Ceramic Substrates

Bondability and interfacial reaction between dielectric and insulator layers have been examined to obtain a basic understanding of bonding mechanisms. Lead-containing complex perovskite was used as a dielectric material. Two kinds of glass-ceramics were used as insulator material; lead borosilicate glass containing Al_2O3 (insulator A) and the same containing Al₂O₃ and M_gO (insulator B). Dielectric and insulator layers did not bond when insulator A was used. When insulator B was used, however, strong bonding was achieved between the two layers by firing the powder compacts at temperatures between 800° and 1000°C. Addition of M_gO to lead borosilicate glass increased the thermal expansion coefficient to that of the dielectric and enhanced the formation of reaction layers, resulting in good bonding. Two reaction layers were identified. The main reaction products were enstatite and bredigite for one layer contacting the dielectric, and enstatite and a compound with the same diffraction pattern as that of faujasite for the other layers contacting insulator B.     

Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

Topological crystalline insulators (TCIs) are predicted to be a promising candidate material for ultra‐broadband photodetectors ranging from ultraviolet (UV) to terahertz (THz) due to its gapless surface state and narrow bulk bandgap. However, the low responsivity of TCIs‐based photodetectors limits their further applications. In this regard, a high‐performance photodetector based on SnTe, a recently developed TCI, working in a broadband wavelength range from deep UV to mid‐IR with high responsivity is reported. By taking advantage of the strong light absorption and small bandgap of SnTe, photodetectors based on the as‐grown SnTe crystalline nanoflakes as well as specific short channel length achieve a high responsivity (71.11 A W^?1 at 254 nm, 49.03 A W^?1 at 635 nm, 10.91 A W^?1 at 1550 nm, and 4.17 A W^?1 at 4650 nm) and an ultra‐broad spectral response (254–4650 nm) simultaneously. Moreover, for the first time, a durable flexible SnTe photodetector fabricated directly on a polyethylene terephthalate film is demonstrated. These results prove the great potential of TCIs as a promising material for integrated and flexible optoelectronic devices.     

复合绝缘子动载机械性能探讨

对不同长度复合绝缘子在不同基础拉伸载荷下叠加不同强度扭矩进行了拉扭组合试验,并分别对单联和双联、压接式和楔接式复合绝缘子进行了拉扭组合试验。试验结果表明,在正常情况下耐张串载荷对复合绝缘子蠕变性能的影响不大,因此复合绝缘子可应用于耐张串。     

应用质量管理实现500kV线路带电作业的实践

本介绍合肥供电公司如何应用质量管理理论和方法开展质量管理(QC)小组活动，实现500kV线路带电更换四联串耐张绝缘子的创新与实践过程。本成果是全国电力行业QC成果第10名，并获得全国优秀QC成果奖。     

Adiabatic photo-steering theory in topological insulators

Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are selected as the optimal systems that exhibit a prominent change in their properties following the application of this method. Two specific examples of photo-steered quantum phenomena, which reflect topological aspects of the electronic systems at hand, are presented. One is the integer quantum Hall effect described by the Haldane model, and the other is the quantum spin Hall effect described by the Kane–Mele model. The topological quantities associated with these phenomena are the conventional Chern number and spin Chern number, respectively. A recent interesting idea, time-reversal symmetry breaking via a temporary periodic external stimulation, is also discussed.     

复合绝缘子弱憎水性状态描述方法Ⅲ——液滴面积法的适用性

寻求合适的方法及参数来描述染污复合绝缘子的弱憎水性状态,对弱憎水性状态给出明确的定义,并对当前已有的7个憎水等级进一步细化。通过10μL靛蓝溶液在染污高温硫化硅橡胶试片表面的垂直投影面积,来反映污层的憎水性状况,并尝试将液滴面积与染污绝缘芯棒的污闪电压建立联系,以揭示弱憎水性阶段憎水性能改变对绝缘子污闪特性的影响。结合液滴在污层表面的形态以及试品的污闪特性,在人工污秽试验的基础上将当前憎水等级HC7进一步细化为四个阶段,分别是HC7A、HC7B、HC7C及HC7D。比较液滴面积、液滴接触角以及喷水分级试验结果,将新憎水等级HC7B定义为弱憎水性状态。试验研究认为:液滴面积法弥补了液滴接触角法在染污试品呈弱憎水性状态下的不足,可以用于弱憎水性阶段的憎水特性研究;而憎水性较强时,面积法对憎水性的辨识能力有限,选用接触角法更适合此阶段的研究。