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991.
Fengmei Wang Tofik A. Shifa Peng Yu Peng He Yang Liu Feng Wang Zhenxing Wang Xueying Zhan Xiaoding Lou Fan Xia Jun He 《Advanced functional materials》2018,28(37)
The exponentially growing works on 2D materials have resulted in both high scientific interest and huge potential applications in nanocatalysis, optoelectronics, and spintronics. Of especial note is that the newly emerged and promising family of metal phosphorus trichalcogenides (MPX3) contains semiconductors, metals, and insulators with intriguing layered structures and architectures. The bandgaps of the members in this family range from 1.3 to 3.5 eV, significantly enriching the application of 2D materials in the broad wavelength spectrum. In this review, emphasizing their remarkable structural, physicochemical, and magnetic properties, as well as the numerous applications in various fields, the innovative progress on layered MPX3 crystals is summarized. Different from other layered materials, these crystals will advance a fascinating frontier in magnetism and spintronic devices with their especially featured atomic layered nanosheets. Thus, their crystal and electronic structures, along with some related researches in magnetism, are discussed in detail. The assortments of growth methods are then summarized. Considering their potential applications, the prominent utilization of these 2D MPX3 nanoscrystals in catalysis, batteries, and optoelectronics is also discussed. Finally, the outlook of these kinds of layered nanomaterials is provided. 相似文献
992.
文章以问卷调查和深度访谈相结合的方式获取中国学龄儿童使用英语听说APP的学习内容、学习动机、时长、终端、使用体验和存在问题等第一手数据.通过数据分析对学龄儿童使用听说APP的行为特征和倾向性进行描述,借助建构主义心理学理论从学生和教师因素分析了如何改进此类APP的设计,进而为改进学龄儿童英语听说类APP的框架设计提供决策依据. 相似文献
993.
本文分析了光电电流互感器的测试与校验的方法,阐述了光电电流互感器的结构和工作原理,并对光电电流互感器的测试系统进行了研究,同时还对光电电流互感器的虚拟校验仪进行了说明,最后总结了光电电流互感器测试与校验方法的要点,旨在研究出适合光电电流互感器的测试发展,从而推动光电电流互感器的发展和应用. 相似文献
994.
针对脉冲频率调制(PFM)开关电源(SMPS)集成电路,提出了抗电磁干扰(EMI)设计的两种方法.通过采用零电流检测电路,控制开关电源集成电路中的开关金属氧化物半导体场效应晶体管(MOSFET)在第一个谷底导通,从而降低导通电流的尖峰值.通过采用恒压和恒流设计技术,使开关电源集成电路中的电压和电流得到限制,有助于降低电流纹波.采用CSMC lμm 40 V高压工艺设计了PFM开关电源集成电路SX1618,将以上两种抗电磁干扰设计方法应用在该电路的设计中,并设计了针对性的保护结构.完成SX1618整体仿真和版图设计后进行了流片和封装,并将其应用在实际的开关电源中,经测试,开关电源的抗电磁干扰能力符合标准. 相似文献
995.
996.
997.
We theoretically predict the appearance of a persistent charge current in a Rashba ring with a normal and a ferromagnetic lead under no external bias. This charge current is the result of the breaking of the time inversion symmetry in the original persistent pure spin current induced by the Rashba spin-orbit coupling (RSOC) in the ring due to the existence of the ferromagnetic lead. With the Keldysh Green''s function technique, we find that not only the magnitude and sign but also the spin polarization of the generated charge current is determined by the system parameters such as the magnetization direction of the ferromagnetic lead, the tunneling coefficient, the strength of the RSOC and the exchange energy of the ferromagnetic lead, which are all tunable in experiments, that is, a controllable persistent spin-polarized charge current can be obtained in such a device. 相似文献
998.
Minjie Liu Gaoshan Huang Ping Feng Qinglei Guo Feng Shao Ziao Tian Gongjin Li Qing Wan Yongfeng Mei 《半导体学报》2017,38(6):064006-5
Silicon nanomembrane (SiNM) transistors gated by chitosan membrane were fabricated on plastic substrate to mimic synapse behaviors. The device has both a bottom proton gate (BG) and multiple side gates (SG). Electrical transfer properties of BG show hysteresis curves different from those of typical SiO2 gate dielectric. Synaptic behaviors and functions by linear accumulation and release of protons have been mimicked on this device:excitatory post-synaptic current (EPSC) and paired pulse facilitation behavior of biological synapses were mimicked and the paired-pulse facilitation index could be effectively tuned by the spike interval applied on the BG. Synaptic behaviors and functions, including short-term memory and long-term memory, were also experimentally demonstrated in BG mode. Meanwhile, spiking logic operation and logic modulation were realized in SG mode. 相似文献
999.
In this paper, the MCI (multipath crossover interconnection) technique for octagon single and symmetrical spiral inductors has been presented to improve the quality factor. The metal wires of the single and symmetrical inductors formed by the top metal are divided into multiple segments according to the depth of the skin effects. The outermost path of the metal is crossover-interconnected to the innermost path by the underlayer metal and via The crossover technique makes the lengths of the total current paths between two ports approximately equal to each other. Therefore, the induced magnetic flux and resistance of each path can be balanced and the Q-factor of spiral inductors can be enhanced. The proposed MCI technique has been validated by the electromagnetic simulation with the 130-nm 1P6M SiGe BiCMOS process. For the devices with occupying areas of 240×240μm2, results of electromagnetic simulation show that about 24% improvement in the Q-peak (3.3 GHz) of the MCI single inductor as compared to conventional single inductors (3.1 GHz), and about 88.1% improvement in the Q-peak (3.2 GHz) of the MCI symmetrical inductor as compared to conventional symmetrical inductors (1.8 GHz). 相似文献
1000.
Sook-Yee Yoon 《Tetrahedron letters》2008,49(27):4282-4285
A dithiacyclophane was employed as a precursor to the title compound. A conformational study of the dithiacyclophane revealed a unique phenomenon in its terphenyl unit: one ring is rigidly held, the other terminal ring undergoes free rotation and the central ring exhibits restricted mobility. The aromatic protons of the biphenyl unit are all shielded by the dihydropyrene unit and well resolved in the 1H NMR spectrum, consistent with a ring current effect extended to eight conjugated carbon atoms away from the molecular plane of dihydropyrene. 相似文献