浅谈发热现象及应对方法

高压设备接头发热对设备的正常运行非常重要,同时也是供电可靠率的一项重要指标。现在红外测温能及时发现运行设备的发热缺陷,并将信息反馈到检修班组及时进行处理。本文对发现的发热现象的分析、如何应对也是现在设备检修的首要问题。设备检修时检修人员要严格按照检修工艺工作,对检修后设备检测接触电阻,人员的技术培训,以及对各类型发热的案例、应对方法进行了介绍。     

环周声波扫描测井仪（CAST）原理及应用

人们正在努力使地层的描述像井眼特征那样更全面、更容易理解,作为成像装置,声成像测井仪主要应用于确定地层的构造特征、沉积环境,描述确定井眼的几何形态和井壁垮塌情况。此外,它还能在套管中确定套管厚度,了解套管的变形和腐蚀情况。文章描述了声成像测井仪器的工作原理,基本模型和测井过程中不同衰减因素的影响以及具体应用,使人们认识到声成像测井仪的重要性。     

SAR成像系统重频抖动的影响及补偿

合成孔径雷达(SAR)系统要求时间严格同步,从而可利用脉冲间的相干性进行方位处理。推导了重频抖动造成的时间同步误差对SAR成像方位聚焦的影响以及其极限值,并给出了补偿方法。采用实际系统参数进行了仿真验证,并分析了存在重频抖动误差的实际SAR成像雷达系统,实测数据处理和补偿结果验证了理论的有效性。所提方法对实际雷达系统的设计、问题分析和SAR成像处理误差补偿有指导意义,具有较高的实用价值。     

高帧率步进频穿墙成像雷达扫频方法

步进频是穿墙成像雷达的常用波形,传统采用锁相合成技术的步进频穿墙成像雷达的跳频时间长,帧率很低,难以满足穿墙雷达实时成像的要求。为了解决这个问题,提出了一种新的扫描方案,可以通过现场可编程门阵列（FPGA）实现对扫描方式的可调控制,在不影响回波波形及成像效果的情况下显著提高了步进频穿墙成像雷达的帧率。在2 MHz的频率步长以及2.5 GHz的频段范围内时,实际成像帧率可以达到14 Hz,在一定程度上满足了实时成像的要求。试验测试结果验证了所提方法的可行性。     

基于回波数据压缩的MIMO-SAR成像方法

针对多发多收合成孔径雷达（MIMO-SAR）高分辨成像的回波数据量过大问题,提出了一种基于数据压缩的MIMO-SAR成像方法。通过对MIMO-SAR回波数据的分析,补偿了由于MIMO雷达收发分置导致的相位误差;其次利用距离徙动算法(RMA)对回波数据进行预处理并分析了其稀疏性;然后针对预处理后的回波数据进行压缩传输,在接收端利用压缩感知重构算法获得回波数据在距离多普勒域的稀疏表示并进行成像处理。仿真结果表明,所提方法可以在大幅压缩MIMO-SAR回波数据的基础上实现准确成像。     

Pictures and prose: exploring the impact of literary and film tourism

While literary tourism has a long history traceable back to the seventeenth century, the considerable growth of interest and popularity in literary tourism research among academics and the tourism industry has been recognised only since the mid-1990s [Hebert, D. T. (1996). Artistic and literary places in France as tourist attractions. Tourism Management, 17(2), 77–85]; [Squire, S. J. (1993). Valuing countryside: Re?ections on Beatrix Potter tourism. Area, 24, 5–10]; [Squire, S. J. (1994). The cultural values of literary tourism. Annals of Tourism Research, 21, 103–120]. With this in mind, this paper aims to investigate how tourism stakeholders can take advantage of the positive promotional impacts that a book and film linkage can have on specific destinations. It also examines how tourism patterns and trends in these destinations have been subsequently influenced and transformed. Within an exploratory case study mode, special emphasis will be placed on two international case studies (Ireland and Indonesia – in particular Bali) which have been associated with internationally recognised books and their subsequent blockbuster films. The findings suggest that both literary and film tourism have a positive effect on these destinations due to an increased growth in their tourism arrivals once the location was referred to in a book and afterwards used as the setting in the related film. This paper will add to the current knowledge base on film and literary tourism and create an awareness of the strength of this form of tourism for international tourism destinations.     

高端医学影像先进医疗器械业发展战略探析

本文以新兴产业之一的生物医学工程产业为研究对象，并以其中的高端医学影像先进医疗器械业为例，在对其产业发展的中外现状与动向论述基础上，指出国内产业发展的问题所在，并从经济社会学关于产业发展“嵌入性”及社会资本理论“公共财”视角提出整合既有力量，构建医学视角的医学影像医疗器械平台和经济社会学视角的医学影像医疗器械产业平台，建立适应高端医学影像先进医疗器械业良性发展的运行机制和产业发展环境。     

On technological objects and the adoption of technological product innovations: rules, routines and the transition from analogue photography to digital imaging

We extend the transformational model of social activity proposedin recent realist social theory by importing into it a theoryof technological objects and technological change. The paperbegins with an account of the transformational model, focusingparticularly on the relationship between routines and socialrules. We then outline a theory of what we call the ‘technicalidentity’ of technological objects, drawing on the notionof collective assignments of agentive functions proposed bythe philosopher John Searle. Finally, we link this theory tothe transformational model and derive three broad categoriesof technological change. The framework as a whole is illustratedwith empirical material drawn from a recent study of the shiftfrom analogue photography to digital imaging in consumer photography.     

Effect of electromagnetic field accompanying the magnetic resonance imaging on human heart rate variability – a pilot study

The effect of electromagnetic field on cardiovascular system in the literature is defined in ambiguous way. The aim of this study was to evaluate the effect of electromagnetic field on the heart rate variability (HRV) during the examination with magnetic resonance. Forty-two patients underwent Holter ECG heart monitoring for 30 minutes twice: immediately before and after the examination with magnetic resonance imaging (MRI). HRV was analysed by assessing a few selected time and spectral parameters. Is has been shown that standard deviation of NN intervals (SDNN) and very low frequency rates increased, whereas the low frequency:high frequency parameter significantly decreased following the MRI examination. These results show that MRI may affect the HRV most likely by changing the sympathetic-parasympathetic balance.     

Attributes of nuclear imaging centers impacting physician referrals for single-photon emission computed tomography myocardial perfusion imaging tests

Aim: To evaluate nuclear imaging center attributes that cardiologists and primary care physicians (PCPs) consider when referring patients for single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) tests, and how these attributes impact physician referral decisions in the United States.

Methods: A targeted literature review and seven one-to-one interviews with physicians and imaging center directors were conducted to identify attributes that could impact physicians’ referral decisions. The impact of the identified attributes was assessed via an online discrete choice survey among eligible PCPs and cardiologists randomly selected from a nationally representative panel, and quantified with an odds ratio (OR) scale estimated with a multivariable logistic regression.

Results: Nine two-level attributes were identified: ease of the referral process, waiting time for tests, insurance preauthorization assistance, time to receive results, conclusive test reports, patient satisfaction, a protocol for rapid conversion from an exercise to a pharmacological stress test, patient communication, and assistance with parking/wheelchair access. A total of 410 physicians, including 208 (50.7%) cardiologists and 202 (49.3%) PCPs completed the survey. Among all physicians, a protocol that allows for a rapid conversion from an exercise to a pharmacological stress test (OR?=?2.9) and preauthorization assistance (OR?=?2.6) were the most impactful attributes. Additionally, cardiologists preferred imaging centers that provide an easy referral process (OR?=?2.7), while PCPs favored centers offering a conclusive test report (OR?=?2.4).

Limitations: Some center features that might impact physician referral decision were not evaluated in this study, if they were not easily changeable from an imaging center’s perspective.

Conclusions: The availability of a protocol for rapid conversion from an exercise to a pharmacological stress test and preauthorization assistance had the most significant impact on physician referral decisions for SPECT-MPI. Additionally, cardiologists preferred centers providing an easy referral process, while PCPs favored those offering a concluding statement and actionable steps in test reports.