磁控RF-SIM卡的设计与实现

在非接触式手机移动支付日益盛行的背景下,结合智能卡、RFID、磁控等技术,提出一种磁控RF-SIM卡的设计和实现模式.该磁控RF-SIM卡由多芯片的硬件架构和多任务、多应用的卡操作系统软件架构组成.它为RF-SIM卡产品带来更大的竞争力,为推动手机移动支付的发展提供了有益的帮助.     

量子磁盘表面磁场分布模拟

量子磁盘由于记录点尺寸很小,用常规的磁场测量方法无法对其表面磁场分布数值图进行测试。为了证实量子磁盘的可行性,该文对量子磁盘表面的磁场分布用有限元软件进行模拟计算,在假设量子磁盘的磁化方向为水平磁化的前提下,得到了圆形量子点直径为20nm;量子点间距离为10nm;方形量子点边长为20nm,间距为20nm的情况下量子磁盘的二维表面磁场分布图,证实了其表面磁场分布具有明显的周期性,周期长度为量子点大小加上量子点间距离。并且所得到的磁场分布图为量子磁盘的理论研究提供了一定的参考数据。     

Knowledge work and practices of seeing: Epistemologies of the eye,gaze, and professional vision

Much practice within organizations is to some extent embodied in and centered on the visual capacities of the agent, the acting subject. Distinguishing between ‘epistemologies of the eye’, i.e. theories of how knowledge is acquired through visual practices, and ‘practices of seeing’, i.e. theories and studies of how vision and visuality are actually used in everyday working life, the paper points to the need to understand vision and visuality in organizational practice. Using the case of functional magnetic resonance imaging (fMRI), it is suggested that professional vision, i.e. practices of seeing that are shared within epistemic communities, is firstly technologically mediated and, secondly, based on the ability to combine vision, speech, gesture, and other embodied and cognitive resources in order to make sense of the images produced by fMRI technology. The paper concludes that organization theory should examine practices of seeing in greater detail and as part of the project in order to understand how knowledge is constituted and used as a collectively constituted resource within organizations.     

Safety First: Recognizing and Managing the Risks to Child Participants in Magnetic Resonance Imaging Research

Specialized and up-to-date knowledge is required to identify and manage the risks associated with advanced biomedical research. Additional complexities need to be considered when the research involves infants or young children. In this article, we focus on recent information about the physical risks of pediatric magnetic resonance imaging research and highlight information gaps. With an eye to assisting institutional review boards and researchers, we consider strategies for the management of these risks and formulate key questions aimed at exposing hidden hazards. Institutional review boards should ask these questions, and researchers should bear them in mind as they develop research protocols.     

Disclosure of Unknown Harms in Magnetic Resonance Imaging Research

Unknown harms are by their nature difficult to communicate. While magnetic resonance imaging (MRI) has known risks (e.g., metal projectiles, dislodgement of medical implants), this imaging modality also has potential unknown long-term negative health effects associated with its static magnetic fields. We carried out a research ethics board (REB) file review of previously approved MRI research studies and found that unknown risks were either left undisclosed or were inadequately disclosed to research participants and REBs. This article outlines issues raised by our REB file review and suggests steps that should be taken in order to satisfactorily communicate information about potential unknown harms of MRI.     

Multivariate functional response low‐rank regression with an application to brain imaging data

We propose a multivariate functional response low‐rank regression model with possible high‐dimensional functional responses and scalar covariates. By expanding the slope functions on a set of sieve bases, we reconstruct the basis coefficients as a matrix. To estimate these coefficients, we propose an efficient procedure using nuclear norm regularization. We also derive error bounds for our estimates and evaluate our method using simulations. We further apply our method to the Human Connectome Project neuroimaging data to predict cortical surface motor task‐evoked functional magnetic resonance imaging signals using various clinical covariates to illustrate the usefulness of our results.     

钙钛矿锰氧化物为基体的二相复合体低场室温高磁电阻研究

综述了国内外对钙钛矿锰氧化物为基体的二相复合体低场磁电阻研究现状,提出了钙钛矿锰氧化物低场室温高磁电阻实现的新途径。     

组合磁光光纤光栅的磁场敏感性分析

磁光光纤光栅是一种具有磁光效应的特殊光栅,可直接用于本征型的磁场传感或通过磁控的方式实现可调光子信息处理。该文采用分段均匀模型分析了几种组合磁光光纤Bragg光栅中左右旋圆偏振光的偏振相关损耗对磁场的敏感性,计算表明,均匀磁光光纤光栅的中心区段对磁场最为敏感。提出了一种比均匀磁光光栅更加灵敏的F-P型组合光栅传感结构,可更好地用于较弱磁场下偏振相关损耗的检测。     

微流量智能电磁流量计的研究

根据电磁流量计的基本原理,对其微流量测量技术进行了研究。文中提出了一种运用等效坎截面法的变器结构设计,并对相应的权重函数和阻力损失进行了计算。通过对几种信号处理方法的比较,选择了较佳的基线信号处理方法。在此基础上,围绕单片机展开设计,实现了仪表的智能化和有效的功能。根据流量计栓定规程对样机进行实液标定的结果表明,样机设计达到了预期效果。     

Sex differences in the development of mild cognitive impairment and probable Alzheimer’s disease as predicted by hippocampal volume or white matter hyperintensities

This study examined biological sex differences in the development of mild cognitive impairment (MCI) and probable Alzheimer’s disease (AD) development as predicted by changes in the hippocampus or white matter hyperintensities. A secondary data analysis of the National Alzheimer’s Coordinating Center Uniform Data Set was conducted. We selected samples of participants with normal cognition at baseline who progressed to MCI (n = 483) and those who progressed to probable AD (n = 211) to determine if hippocampal volume or white matter hyperintensities (WMH) at baseline predicted progression to probable AD or MCI and whether the rate of progression differed between men and women. The survival analyses indicated that changes in hippocampal volumes affected the progression to probable AD (HR = 0.535, 95% CI [0.300–0.953]) only among women. White men had an increased rate of progression to AD (HR = 4.396, CI [1.012–19.08]; HR = 4.665, 95% CI [1.072–20.29]) compared to men in other race and ethnic groups. Among women, increases in hippocampal volume ratio led to decreased rates of progressing to MCI (HR = 0.386, 95% CI [0.166–0.901]). Increased WMH among men led to faster progression to MCI (HR = 1.048. 95% CI [1.011–1.086]). Women and men who were older at baseline were more likely to progress to MCI. In addition, results from longitudinal analyses showed that women with a higher CDR global score, older age at baseline, or more disinhibition symptoms experienced higher odds of MCI development. Changes in hippocampal volumes affect the progression to or odds of probable AD (and MCI) more so among women than men, while changes in WMH affected the progression to MCI only among men.