同轴方形载流线圈间的磁力(英文)

为获得二同轴方形载流线圈间相互作用磁力，计算出了线圈间的互感系数。将虚功原理作为一种简捷方法加以运用，对该力极值位置进行了分析和图示。讨论平面内二同心方形线圈载流时一线圈不受磁张力的优良力学状态。     

The Efficacy of Different Methods for Informing the Public About the Range Dependency of Magnetic Fields from High Voltage Power Lines

The AC electric and magnetic fields associated with high voltage power lines have become a concern as a possible health risk. In most cases the strength of these fields decreases as the inverse square of the distance from the line. In earlier work, we found that laypeople do not understand how rapidly field strength decreases with distance. Most believe that any high voltage power line they can see is exposing them to strong fields. This paper confirms the earlier finding and explores a number of strategies which might be used in risk communications to correct this misperception. We found it relatively easy to provide subjects with a better understanding of the range-dependency of magnetic field strength. Moreover, the quality of this acquisition was apparently independent of the manner in which they were instructed. Such successful instruction is markedly different from the well-established difficulty of teaching people about many qualitative domains, such as physics or ideas in probability. Clearly, while some erroneous beliefs are highly resistant to change, others can be altered quite readily. We suspect that an important distinction between knowledge about the range-dependency of power-frequency magnetic fields and less tractable topics involves the presence or absence of prior folk-theories or "mental models" of the domain.     

Prevalence analysis of urinary incontinence after radical prostatectomy and influential preoperative factors in a single institution

Aims: To assess prevalence of urinary incontinence (UI) after radical prostatectomy (RP) and to analyze which preoperative characteristics of the patients have influence on UI.

Methods: Between 2002 and 2012, 746 consecutive patients underwent RP for clinically localized prostate cancer. We defined UI according to International Continence Society (ICS) definition: “the complaint of any involuntary leakage of urine” after 12?months of recovery, international consultation on incontinence questionnaire (ICIQ-SF) and pads/day was collected too. Clinical features and magnetic resonance imaging measurements were assessed. A multivariable logistic regression model predicting incontinence were built-in after adjust by cofounding factors and bootstrapping.

Results: About 172 (23%) of the patients were classified as incontinent according to the ICS definition. The mean value of the ICIQ-SF was 10.87 (±4). 17.8% of patients use at least one pad/day, 11.9% use more than one pad/day. The preoperative factors independently influential in UI are: age [OR: 1.055; CI 95% (1.006–1.107), p?=?.028], urethral wall thickness [OR: 5.03; CI 95% (1.11–22.8), p?=?.036], history of transurethral resection of the prostate [OR: 6.13; CI 95% (1.86–20.18), p?=?.003] and membranous urethral length [OR: 0.173; CI 95% (0.046–0.64), p?=?.009]. The predictive accuracy of the model is 78.7% and the area under the curve (AUC) value 71.7%.

Conclusions: Urinary incontinence after radical prostatectomy has different prevalence depending on the definition. Age, prior transurethral resection of the prostate (TURP), membranous urethral length (MUL) and urethral wall thickness (UWT) were risk factors.     

The digital rainbow: Some history and applications of numerical spectrum analysis

Statistical concepts and techniques are basic to scientific investigation. One concept that enjoys both a theoretical and a physical existence is the spectrum. A spectrum may be described as a display of the intensity or variability of a phenomenon versus period or frequency. Spectra are particularly useful in the study of systems subject to resonance, but have many other uses. This paper begins with some of the historical development of the field, describing a sequence of contributions by Michelson, Schuster, Einstein, Fisher, Bartlett, Tukey, and Whittle. The paper next presents collaborative applications to the study of the free oscillations of the earth, to the dispersion of seismic surface waves and to nuclear-magnetic-resonance spectroscopy. Finally, there is mention of open problems and opinions on future directions.     

A Stochastic Geometry Model for Functional Magnetic Resonance Images

In functional magnetic resonance imaging, spatial activation patterns are commonly estimated using a non-parametric smoothing approach. Significant peaks or clusters in the smoothed image are subsequently identified by testing the null hypothesis of lack of activation in every volume element of the scans. A weakness of this approach is the lack of a model for the activation pattern; this makes it difficult to determine the variance of estimates, to test specific neuroscientific hypotheses or to incorporate prior information about the brain area under study in the analysis. These issues may be addressed by formulating explicit spatial models for the activation and using simulation methods for inference. We present one such approach, based on a marked point process prior. Informally, one may think of the points as centres of activation, and the marks as parameters describing the shape and area of the surrounding cluster. We present an MCMC algorithm for making inference in the model and compare the approach with a traditional non-parametric method, using both simulated and visual stimulation data. Finally we discuss extensions of the model and the inferential framework to account for non-stationary responses and spatio-temporal correlation.     

帕金森病患者额叶质子磁共振波谱与额叶认知功能

目的利用氢质子磁共振波谱（1H MRS）技术研究帕金森病（PD）患者额叶的代谢变化与额叶认知功能的关系。方法PD患者20例和正常对照20例行1H MRS检查,测定双侧额叶的N-乙酰天门冬氨酸/肌酸（NAA/Cr）、N-乙酰天门冬氨酸/胆碱复合物（NAA/Cho）和胆碱复合物/肌酸（Cho/Cr）比值,同时测定MMSE、画钟试验、重复100减7试验、连线测验、词语流畅性测验,计算其相关性。结果H＆Y分级≥3级的重症PD患者额叶NAA/Cr比值与画钟试验、连线测验、词语流畅性测验之间的相关性具有统计学意义,与重复100减7试验及MMSE无相关性。结论重症PD患者额叶NAA/Cr比值与画钟试验、连线测验、词语流畅性测验相关,因而可用以评估额叶认知功能。     

微波ECR等离子体参数测量及分析

利用双探针测试了微波ＥＣＲ等离子体参数，发现获得大面积均匀等离子体源强烈依赖于轴向磁场梯度，等离子体参数受气压影响亦很大．测量结果与理论分析一致．     

毫米波回旋管的非线性分析

本文对四毫米(75GHz)回旋管进行了非线性分析。从电磁场作用下单粒子轨道理论出发,计算了工作在H_(521)和H_(041)模式,二次回旋谐波的两种管型的优化电子效率,并对影响效率的各因素进行了分析讨论。为了抑制热测中发现的8mm基波振荡讯号(H_(221)模),进行了必要的计算和分析。为设计中确定管子的最佳效率,以及调整热测条件等提供了理论依据。     

带引导场圆极化自由电子激光器的电子稳态轨迹

本文用扰动方法,逐级求解了带导引场圆极化自由电子激光器的电子非线性稳态运动方程。计算表明,在一级近似下,文中给出的电子稳态轨迹包含了文献[1]的结果,并且具有比[1]的结果更合理的物理意义。     

磁化黑洞吸积盘的磁耦合过程

对磁化黑洞吸积盘的提能机制之一磁耦合(MC)过程作了详细的讨论,重点分析了MC过程的等效电路模型,在满足磁通守恒条件下引入Kerr度规,得到了黑洞视界面与吸积盘之间的一种更为合理的映射关系。