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排序方式: 共有95条查询结果,搜索用时 15 毫秒
71.
针对当前行人运动特征监测方案中存在运动信息种类单一、特征提取不完善、识别算法复杂且需要依赖专业检测设备等问题,提出基于智能移动端内置惯性传感器的行人运动特征自动辨识方案,为运动特征识别提供准确多样的运动信息。采集移动端MEMS加速度计输出信息后,分别提取加速度数据的三种时域及频域特征后,通过训练最邻近规则分类器实现行人行走、跑步和上下楼梯运动模式的自动识别。不同年龄不同身高的男女性运动特征提取实验结果表明,基于最邻近规则的移动端行人运动特征辨识方法对4种日常活动的平均查准率和查全率分别达到88.7%和90.3%,对提高微惯性行人导航系统普适性具有促进作用。 相似文献
72.
Gaopei Pan 《中国物理 B》2022,31(12):127101-127101
We summarize the recent developments in the model design and computation for a few representative quantum many-body systems, encompassing quantum critical metals beyond the Hertz-Millis-Moriya framework with pseudogap and superconductivity, SYK non-Fermi-liquid with self-tuned quantum criticality and fluctuation induced superconductivity, and the flat-band quantum Moiré lattice models in continuum where the interplay of quantum geometry of flat-band wave function and the long-range Coulomb interactions gives rise to novel insulating phases at integer fillings and superconductivity away from them. Although the narrative choreography seems simple, we show how important the appropriate model design and their tailor-made algorithmic developments - in other words, the scientific imagination inspired by the corresponding fast experimental developments in the aforementioned systems - compel us to invent and discover new knowledge and insights in the sport and pastime of quantum many-body research. 相似文献
73.
Weilun Jiang 《中国物理 B》2022,31(4):40504-040504
We systematically test the performance of several Monte Carlo update schemes for the (2+1)d XY phase transition of quantum rotor model. By comparing the local Metropolis (LM), LM plus over-relaxation (OR), Wolff-cluster (WC), hybrid Monte Carlo (HM), hybrid Monte Carlo with Fourier acceleration (FA) schemes, it is clear that among the five different update schemes, at the quantum critical point, the WC and FA schemes acquire the smallest autocorrelation time and cost the least amount of CPU hours in achieving the same level of relative error, and FA enjoys a further advantage of easily implementable for more complicated interactions such as the long-range ones. These results bestow one with the necessary knowledge of extending the quantum rotor model, which plays the role of ferromagnetic/antiferromagnetic critical bosons or Z2 topological order, to more realistic and yet challenging models such as Fermi surface Yukawa-coupled to quantum rotor models. 相似文献
74.
Co-assembly of ABC linear triblock copolymer/nanoparticle into bump-surface multicompartment hybrids in selective solvent was studied through self-consistent field theory (SCFT) simulation. Results from three-dimensional SCFT simulation showed that the hybrid morphology depended on the length and number of grafted chains, whereas the number and shape of bumps relied on nanoparticle size. Moreover, the simulation results showed that the length and number of grafted chains had equivalent effect on hybrid morphology. Calculated results indicated that entropy was a more important factor than enthalpy in the co-assembly. 相似文献
75.
运用平面波展开法(PWE),针对光子晶体在短波长段发光二极管(LED)领域上的应用,主要选择高频禁带模式,研究了4种具有较大应用潜力的二维光子晶体结构,包括正方空气柱结构、三角空气柱结构、正方介质柱结构和三角介质柱结构。在不同晶格常数、占空比(AFF)、柱半径和晶格常数比下,分析了TE模式和TM模式光子禁带的变化。数据分析表明,光子禁带中心波长随AFF增加而变小。相比于其他结构,正方介质柱结构更适于短波段光子晶体LED来提高其出光效率,三角介质柱结构和三角空气柱结构适合用于构造短波段偏振光LED。 相似文献
76.
Mechanism of micro-waviness induced KH<sub>2</sub>PO<sub>4</sub> crystal laser damage and the corresponding vibration source 下载免费PDF全文
The low laser induced damage threshold of the KH2PO4 crystal seriously restricts the output power of inertial confinement fusion.The micro-waviness on the KH2PO4 surface processed by single point diamond turning has a significant influence on the damage threshold.In this paper,the influence of micro-waviness on the damage threshold of the KH2PO4 crystal and the chief sources introducing the micro-waviness are analysed based on the combination of the Fourier modal theory and the power spectrum density method.Research results indicate that among the sub-wavinesses with different characteristic spatial frequencies there exists the most dangerous frequency which greatly reduces the damage threshold,although it may not occupy the largest proportion in the original surface.The experimental damage threshold is basically consistent with the theoretical calculation.For the processing parameters used,the leading frequency of micro-waviness which causes the damage threshold to decrease is between 350-1 μm-1 and 30-1 μm-1,especially between 90-1 μm-1 and 200-1 μm-1.Based on the classification study of the time frequencies of microwaviness,we find that the axial vibration of the spindle is the chief source introducing the micro-waviness,nearly all the leading frequencies are related to the practical spindle frequency(about 6.68 Hz,400 r/min) and a special middle frequency(between 1.029 Hz and 1.143 Hz). 相似文献
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采用自旋波的理论研究反铁磁层间耦合强度和不同自旋值对铁磁—反铁磁双层系统磁性质的影响,在层间反铁磁耦合情况下.得出了不同自旋值时每层子晶格交叉点的温度,在低温下表现出量子效应。 相似文献