准各向同性高温超导股线交流损耗的实验研究

高温超导体的交流损耗直接影响超导电力装置的运行成本和稳定性,是判断超导电力设备设计是否合理的重要特性之一.在阐述准各向同性高温超导股线结构特点的基础上,首先对准各向同性高温超导股线的交流损耗和磁滞损耗进行仿真研究,利用有限元软件Comsol Multiphysics分析了交流背景磁场下的损耗,然后在对光纤布拉格光栅(optical fiber Bragg grating,简称FBG)波长与损耗关系标定的基础上,使用光纤布拉格光栅测量交流背景磁场下的交流损耗.理论计算与实验结果相吻合,表明在工频和液氮温度下股线的交流损耗以磁滞损耗为主.     

融合心率变异性与表情的非接触心理压力检测

针对现有心理压力检测方法主观性强、准确率低,且无法连续监测的问题,提出了一种融合心率变异性(HRV)与人脸表情的非接触式心理压力检测方法.该方法通过成像式光电容积描记(IPPG)技术从视频图像中提取HRV信息,并通过VGG19网络建立表情识别模型,获得人脸表情.将HRV及表情共同作为特征输入,利用支持向量机进行训练分类...     

受光阑限制厄米-双曲正弦-高斯光束的解析传输公式

从Collins公式出发,使用厄米多项式展开的方法,对厄米-双曲正弦-高斯光束（HShG）光束通过有硬边光阑限制的近轴ABCD光学系统的传输进行了研究,将其在输出面上的场分布表示成为不完全伽马函数的形式,得出解析表达式。并讨论了该光束的传输特性和该方法的优越性。     

Resistive switching memory for high density storage and computing

The resistive random access memory (RRAM) has stimulated a variety of promising applications including programmable analog circuit, massive data storage, neuromorphic computing, etc. These new emerging applications have huge demands on high integration density and low power consumption. The cross-point configuration or passive array, which offers the smallest footprint of cell size and feasible capability of multi-layer stacking, has received broad attention from the research community. In such array, correct operation of reading and writing on a cell relies on effective elimination of the sneaking current coming from the neighboring cells. This target requires nonlinear I-V characteristics of the memory cell, which can be realized by either adding separate selector or developing implicit build-in nonlinear cells. The performance of a passive array largely depends on the cell nonlinearity, reliability, on/off ratio, line resistance, thermal coupling, etc. This article provides a comprehensive review on the progress achieved concerning 3D RRAM integration. First, the authors start with a brief overview of the associative problems in passive array and the category of 3D architectures. Next, the state of the arts on the development of various selector devices and self-selective cells are presented. Key parameters that influence the device nonlinearity and current density are outlined according to the corresponding working principles. Then, the reliability issues in 3D array are summarized in terms of uniformity, endurance, retention, and disturbance. Subsequently, scaling issue and thermal crosstalk in 3D memory array are thoroughly discussed, and applications of 3D RRAM beyond storage, such as neuromorphic computing and CMOL circuit are discussed later. Summary and outlooks are given in the final.     

Theoretical investigation of total-asymmetric simple exclusion processes with attachment and detachment

In this paper, traffic systems with attachment and detachment have been studied by total-asymmetric simple exclusion processes (TASEPs). Attachment and detachment in a one-dimensional system is a type of complex geometry that is relevant to biological transport with the random update rule. The analytical results are presented and have shown good agreement with the extensive Monte Carlo computer simulations.     

倍增型有机光电探测器的研究进展

介绍了倍增型有机光电探测器的发展、工作机理、性能调控及相关的应用探索.2015年张福俊课题组以单载流子传输通道的给受体混合(质量比约为100∶1)薄膜为有源层,率先报道了界面附近受陷电子诱导空穴隧穿注入的倍增型有机光电探测器,并抑制了器件的暗电流密度.通过优化有源层厚度调控了界面附近受陷电荷的体分布,制备出超窄响应的倍...     

超导量子干涉器件读出电路中匹配变压器的传输特性研究

在磁通调制超导量子干涉器件(SQUID)的读出电路中, 匹配变压器具有放大信号和阻抗匹配的功能, 是实现SQUID低噪声读出的关键元件. 利用模拟SQUID电路对匹配变压器进行性能测试, 研究了不同绕制匝数变压器的传输特性, 确定最佳绕制匝数比. 在变压器拾取SQUID电压信号的耦合网络中, 研究了不同电容对变压器传输特性的影响, 实现了变压器耦合网络参数的匹配和优化. 室温下匝数比为1:20的匹配变压器在匹配电容C=1μF时, 输出源电压增益为21.2, 带宽范围可达到210 kHz. 最后在基于磁通调制式DC SQUID读出电路中, 对匹配变压器的工作性能进行了评估与验证. 关键词： 超导量子干涉器件读出电路 匹配变压器 低噪声 传输特性     

一种应用于心磁噪声抑制的选择性平均方法研究

在心磁信号探测中, 抑制环境噪声是提取心磁信号的关键. 为了提高心磁信号的信噪比, 信号平均得到了广泛地使用. 然而, 由于局部干扰噪声的存在, 对整段数据进行平均的传统方法不可避免地会带来心磁信号的失真. 本文通过采取模版匹配的方式, 提出了一种选择性平均方法. 结果显示, 本方法能有效剔除带有低频波动、脉冲毛刺等干扰的数据段, 获取高质量的平均心磁信号. 关键词： 心磁 信号平均 噪声抑制 信噪比