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51.
Yong Li Qiyuan Feng Sihua Li Ke Huang Mangyuan Ma Weiliang Gan Haibiao Zhou Xiangjun Jin Xiao Renshaw Wang Yalin Lu Wen Siang Lew Qingyou Lu Fusheng Ma 《Advanced functional materials》2020,30(3)
Magnetic skyrmions are topologically nontrivial spin structures, and their existence in ferromagnetically coupled multilayers has been widely reported with a disordered arrangement. Here, a nucleation scenario of ordered skyrmions in nanostructured synthetic antiferromagnetic (SAF) multilayers is proposed and experimentally demonstrated using direct magnetization imaging, indirect magnetometer and magnetoresistance measurement, and micromagnetic simulation. Instead of relying on Dzyaloshinskii–Moriya interaction, the antiferromagnetic interlayer exchange coupling in the SAF multilayers fulfills the role of nucleation and stabilization of skyrmions. The robustness of the proposed skyrmion nucleation scenario is examined against temperature from 4.5 to 300 K and device size from 400 to 1200 nm. Interestingly, these synthetic skyrmions still behave well with a size less than 100 nm. The higher stability than generic magnetic domains can be attributed to topological protection. The results thus provide an artificial skyrmion platform to meet the functional needs of high density and designable arrangement in magnonic and spintronic applications. 相似文献
52.
Peigen Li Teng Ding Junqin Li Chunxiao Zhang Yubo Dou Yu Li Lipeng Hu Fusheng Liu Chaohua Zhang 《Advanced functional materials》2020,30(15)
Because the intrinsic Ge vacancies in GeTe usually lead to high hole concentration beyond the optimal range, many previous studies tend to consider Ge vacancies as negative effects on increasing the figure of merit ZT of GeTe‐based alloys, and consequently have proposed various approaches to suppress Ge vacancies. However, in this work, it is demonstrated that the Ge vacancies can have great positive effects on enhancing the ZT of GeTe‐based alloys when the hole concentration falls into the optimal range. First, hole concentration of GeTe is reduced close to the optimal range by co‐alloying of Pb and Bi, and then the Ge vacancies are increased by adding excess Te into the Ge0.8Pb0.1Bi0.1Te1+x. The Ge vacancies can cause lattice shrinkage and promote rhombohedral‐to‐cubic phase transition. As revealed by first‐principle calculations, theoretical simulations, and experimental tests, Ge vacancies can facilitate the band convergence, suppress the bipolar transport at higher temperature range, and reduce the lattice thermal conductivity. Combining these effects, a peak ZT of 1.92 at 637 K and an average ZT of 1.34 within 300–773 K in Ge0.8Pb0.1Bi0.1Te1.06 can be obtained, demonstrating the great significance of utilizing vacancy‐type defects for enhancing ZT. 相似文献
53.
随着城市的发展,大量人口涌进城市,城市面临着前所未有的压力.利用人群轨迹数据,发现一些人们尚未知道的隐式知识服务社会.本文利用主成分分析PCA和主题模型结合的方法发现波动位置(简称FL)及其主题.即在连续时间片下,空间紧密,主题相同的波动位置形成不同的事件区域(简称EZ).事件区域的研究意义在于理解城市时空下的位置相关性,为城市规划、城市建设等公共服务提供预警.最后本文实验数据采用了微软亚洲研究院Geolife公开数据验证. 相似文献
54.
We report the construction of a novel biosensing nanodevice to detect single, sequence-specific target DNA molecules. Nanodevice assembly occurs through the association of an immobilized F1-ATPase molecular motor and a functionalized gold nanorod via a single 3',5'-dibiotinylated DNA molecule. Target-dependent 3',5'-dibiotinylated DNA bridges form by combining ligation and exonucleation reactions (LXR), with a specificity capable of selecting against a single nucleotide polymorphism (SNP). Using dark field microscopy to detect gold nanorods, quantitation of assembled nanodevices is sufficient to distinguish the presence of as few as 1800 DNA bridges from nonspecifically bound nanorods. The rotary mechanism of F1-ATPase can drive gold nanorod rotation when the nanorod is attached via the DNA bridge. Therefore, rotation discriminates fully assembled devices from nonspecifically bound nanorods, resulting in a sensitivity limit of one zeptomole (600 molecules). 相似文献
55.
This article aims at designing a wavelet alternative to Fourier transform infrared spectra (FTIR). In order to select the most suitable wavelet parameters to perform, several decomposition levels and 53 wavelets were tested by trial and error approach, respectively. The result indicated that discrete meyer wavelet (dmey) associated with its third decomposition level was very efficient for this purpose. On the base of it, a novel library named as Fourier transform infrared wavelet coefficients library (FTIR-WC) has been constructed. Finally, two tools such as library search and structure elucidation were developed to evaluate the capability of the new library system. The results obtained were also compared with those from FTIR library by a variety of indices. The results suggested that the new library performed better but with less volume. This work is expected to propose a novel and practical strategy in infrared spectroscopic analysis. 相似文献
56.
陈福生 《南昌大学学报(理科版)》1990,14(1):1
本文应用理论物理方法研究处于非平衡态的恒星大气,考虑及辐射压力、快速自转和起潮力的作用,得到非球对称情况下的恒星风运动方程。 相似文献
57.
58.
陈福生 《南昌大学学报(理科版)》1988,12(2):1
本文根据含有较多磁单极的一类加速天体的引力场度?,研究加速天体的某些?力学性质,我们得出结论:(1)具有加速运动的天体,即使不?的转动,也会造成两极与?道间的温差。(2)两个极区温度不同,θ=0的极区温度高于θ?π的极区温度。磁菏q的作用能使天体表面温度降低,使引力半径减小, 相似文献
59.
本文利用凝胶渗透色谱和应力松弛方法研究了顺-1,4-聚异戊二烯的粘弹性能对分子量及分布的依赖性。实验结果表明,生胶的松弛模量和最长松弛时间与分子量和分子量分布都有依赖关系,主要是改变τm=KMwβ关系中的K值,对β值的影响甚小。由于本体聚合物的链缠结而导致的非牛顿效应使生胶的τm与KMw的关系偏离3.4法则,这可用缠结网络密度来校正。探讨了生胶的应力松弛过程是橡胶分子链的滑移和解缠结兼有的两种运动。低分子量级份对链缠结网络有显著影响,起稀释剂作用,使网络的临界缠结分子量增高。 相似文献
60.