基于STC89C52与IPM调压调频高压电源

利用Boost电路作为调压模块的设计,利用IPM智能功率模块构成全桥逆变电路实现调频模块设计,采用STC89C52作为核心控制器件,产生相应的控制电压PWM信号以及和控制频率的PFM信号,通过IR2105芯片实现驱动,控制开关管的导通,通过隔离驱动电路实现电能的通断控制,实现电源的电压、频率和幅值可调。实验结果证明该电源具有结构简单、损耗小、体积小、重量轻等优点。同时系统采用的IPM模块拥有自驱动能力、短路保护、欠压保护、过流保护和过热保护等保护,模块化的驱动电路设计,电路的内部引线电感极小,因而使得系统更稳定可靠。     

The Development and Clinical Application of Acoustical Technique in Hip Joint

In many orthopedic conditions affecting thejoints,detail pathoanatomical diagnosis is oftendifficult withoutrelying heavily on the use of diag-nostic imaging techniques and resorting to invasivemethods ofinvestigation[1] .Moreover,convention-al imaging techniques derived mainly from subjec-tive visual interpretation of data and cannot pro-vide mechanical information of structure.Mollan[1] critically investigated the varioustechnical aspects associated with an acousticaltechnique for the study …     

A Design and Construction of 4 Channel Biotelemetry Device Employing Indoor

In this study, 4 channel biotelemetry device was designed and implemented for monitoring physiological and biological signals of the patients at indoor. Body temperature, respiratory rate, heart rate, electrocardiogram (ECG) and electromyogram (EMG) signals were transmitted using 10 mW 433 MHz and 500 mW 868 MHz FM/FSK transmitter with 9.6 Kps transmission speed. At indoor, receive signal strength indicator (RSSI) levels were measured and compared with 433 and 868 MHz carrier frequency. The placement of repeater at indoor was decided as a result of RSSI measurement.     

基于USB技术的工控检测数据存储设计

详细介绍了把现场检测数据存储到移动存储器的设计方法,探讨了如何使用单片机实现U SB移动存储的控制。设计了一个系统,能把现场检测的模拟信号转换成可以被移动存储器识别的数字信号,自动在存储器中建立文件并存储检测数据。给出了电路的整体框图和部分关键电路的连线图,简要说明了软件设计。最后,针对该系统进行实验,结果表明系统符合工况要求。     

心阻抗图波形重建中六导联电极带的设计

目的 设计从胸部体表6个不同部位同步检测阻抗信号的六导联电极带。方法 3条环形电极为电流电极，六对方片电极为电压电极，并制作成颈电极带和胸电极带，由程控电路自动切换不同规格的电极带。结果 1200多例临床检测表明，该电极带测得的胸部体表阻抗信号，可以重建出符合生理意义的主动脉、肺部动脉、心室的体表阻抗变化分量，自动切换电路能正确地选择所需要的电极带。结论 本文设计的六导联电极带符合临床使用要求。     

YY0709-2009医用报警系统标准难点分析与解读

目的分析和解读医用电气设备和医用电气系统中报警系统的主要技术指标视觉报警信号特征和听觉报警信号特征的标准要求。方法结合设计实例和常见问题,对视觉报警信号特征的“距离”要求和“操作者的位置”要求,听觉报警信号的“时域特征”和“频域特征”进行分析,同时对报警信号设计提供建议。结果实现对视觉报警信号特征,听觉报警信号时频特征:脉冲数、脉冲间隔、脉冲群间期、脉冲振幅差异、脉冲有效持续时间、上升时间、下降时间、脉冲频率、谐波数量、谐频与基频幅值差异和音调的论述。结论正确理解标准要求,对产品设计和检验具有重要意义,有助于提高产品质量水平,保障人民群众用械安全。     

Design and Construction of a Low Cost dsPIC Controller Based Repetitive Transcranial Magnetic Stimulator (rTMS)

In this work, a digital signal peripheral interface controller (dsPIC) based repetitive transcranial magnetic stimulator (rTMS) was designed and tested under low voltages. In addition, some limited knowledge of TMS, especially design parameters and notions concerned with it, also were investigated. The reason employing the dsPIC in the design is that design parameters can effectively be controlled. Pulse width modulation and switching output of the control unit, which is necessary to control the rTMS device, were controlled in a more effective way. The other novelty is that developed system can be used for therapeutic or diagnostic purposes in future work provided by digital signal processing performance of dsPIC. Bounded-cylindrical in shape head model made from nonmagnetic material, was used during the tests of the system. Spectrum analyses of clicking sounds were performed with FFT by using MATLAB. The effectiveness of the designed system have been proved by its’ measurement results compared with previous works.     

Wavelet Transformation Based Watermarking Technique for Human Electrocardiogram (ECG)

Nowadays, watermarking has become a technology of choice for a broad range of multimedia copyright protection applications. Watermarks have also been used to embed prespecified data in biomedical signals. Thus, the watermarked biomedical signals being transmitted through communication are resistant to some attacks. This paper investigates discrete wavelet transform based watermarking technique for signal integrity verification in an Electrocardiogram (ECG) coming from four ECG classes for monitoring application of cardiovascular diseases. The proposed technique is evaluated under different noisy conditions for different wavelet functions. Daubechies (db2) wavelet function based technique performs better than those of Biorthogonal (bior5.5) wavelet function. For the beat-to-beat applications, all performance results belonging to four ECG classes are highly moderate.     

神经阈值图谱实验方法的研究

目的：通过对神经刺激阈值的研究，以了解神经电生理学的信号传递及离子通道等神经生理基础的特性。方法：通过神经阈值刺激仪向动物神经纤维束输出刺激电信号，将数字式肌电图仪的电极置放在动物神经支配的肌肉上，检测该肌肉的肌电信号，并反馈至神经阈值检测系统，记录输出刺激电信号的相关参数。结果：通过肌电图仪记录肌肉活动的微小电位差，以了解神经或肌肉的功能状态。电刺激的改变通过精密神经阈值刺激仪作用于相应的神经上，作出波形、频率、占空比及振幅的改变，以获得实验的结果——神经阈值；同时在实验中，我们还使用泰克四踪存储示波器监测从靶向肌肉反馈信号的电流和电压值。结论：阈值大小与占空比无关，但与神经粗细有关；双向波比单向波阈值低，这与去极化导致神经疲劳有关。     

基于睡眠脑电信号和深度学习的抑郁症识别研究

目的 基于睡眠脑电信号,探索深度学习Vision Transformer(ViT)结合Transformer网络对抑郁症患者识别的有效性。方法 首先对28例抑郁症患者和37例正常对照的睡眠脑电信号进行预处理,并将信号转为图像格式,保留其频域及空间域特征信息,之后将图像输送到ViT-Transformer编码网络,分别学习抑郁症患者和正常对照的快速眼动（rapid eye movement, REM）睡眠期和非快速眼动（non-rapid eye movement, NREM）睡眠期的脑电信号特征,并对抑郁症进行识别。结果 基于ViT-Transformer网络,从不同脑电频率角度,发现delta、theta和beta波的组合对抑郁症识别具有比较好的结果。其中,REM期delta-theta-beta波组合的脑电信号特征对抑郁症识别的准确率达92.8%,精准率为93.8%,抑郁症患者的召回率为84.7%,F0.5值为0.917±0.074;NREM期delta-theta-beta波组合的脑电信号特征对抑郁症的识别准确率为91.7%,精准率为90.8%,召回率为85.2%,F0.5值为0...     

带有量化的事件触发预测控制

针对存在量化的网络控制系统,提出了一种基于事件触发机制的预测控制设计方法,其中,信号从传感器传送到控制器和从控制器传送到执行器时需要被量化。建立了带有事件发生器的网络化模型,设计了事件触发机制,给出了预测控制律的设计方法,分析了闭环系统稳定性条件。最后,通过数值仿真验证了本文方法的有效性。     

紧张状态下累积性疲劳的短时心电特征分析研究

目的 现阶段大部分对人体疲劳进行检测与分类的研究都是通过模拟驾驶或者睡眠剥夺的方法来诱发快速疲劳,在进行长期疲劳检测时是否存在一种短时心电特征可作为累积性疲劳的生物标记物尚不明确。 方法 本文采用了一种新的实验方案,具体实施方法是动态跟踪14名被试在参加大学生电子设计大赛期间的心电信号,并收集被试的主观疲劳量表与睡眠时长,首先计算心率变异性、心电熵值、高低频值、平均RR间期等13项特征,接着对清醒与疲劳时的心电特征差值使用威尔科克森符号秩检验进行比较。 结果 实验结果表明,被试在缺少睡眠的情况下主观疲劳程度会加深,短时心电特征的高频值、高低频之比和庞加莱图SD2具有统计学意义。 结论 通过累积性疲劳实验在常见的心电特征中进行探索性分析后发现了具有统计学意义的检测疲劳的生物标记物,短时心电特征未来可用于累积性疲劳的检测。     

听觉皮层优势半球及频率分布的功能MRI研究

目的 研究正常人调幅音刺激任务时听觉皮层的优势半球及不同频率任务刺激时初级及次级听觉皮层的激活情况.方法 对25名健康受试者采用事件相关Sparse设计、正弦调幅音任务下的EPI序列fMRI数据采集,实验刺激声音分别为0.5、2、4 kHz纯音经8 Hz正弦调幅,双耳同时呈现,利用SPM2软件进行数据分析,观察听觉皮层激活的优势半球及不同载波频率调幅音的激活部位、体积和强度.结果 25名受试者中9名由于EPI采集时头动超过最大限度而失败.余16名受试者主要表现为初级听觉皮层激活,且左侧激活的强度和体积均高于右侧.双侧初级听觉皮层的激活体积和强度均随刺激频率的增高而减小;其中6名左侧、7名右侧初级听觉皮层激活的部位表现出清晰的高频偏内,低频偏外的频率响应分布特点.在其他个体,这种分布不明显.次级听觉皮层的激活无明显规律.结论 正常人对调幅音的响应以左侧大脑半球为优势半球;随着刺激频率的增加,初级听觉皮层激活的强度和体积下降,fMRI激活部位的频率分布特点表现为高频偏内,低频偏外.     

交流电压源作用介观LC串联电路的量子效应

利用不变量理论讨论介观LC串联电路系统在交流电压源作用下,得到介观LC电路系统的态随时间演化,结果表明在一定条件下系统态函数具有压缩效应。     

一例长距离多接头的大规模220kV电缆耐压局放同步检测试验

耐压试验同时进行局放检测的高压试验已逐步成为电缆线路竣工投运前或进行维修维护后验证线路绝缘品质的一种有效手段。本文通过报告一例长距离多接头的大规模220kV电缆线路耐压局放同步检测试验,着重介绍应对大规模电缆线路耐压局放试验的基本步骤和方法,主要通过大量图片来展示如何使用和安装高频脉冲电流局放传感器HFCT以实现高灵敏度和高质量的局放检测,同时也介绍了分布式光纤局放同步检测装置的系统构成及其功能特点。对于如何应对使用非无局放耐压电源所必须承受的强大电晕放电噪音干扰,通过试验过程中的一些数据案例分析,说明了线路各个接头点局放检测的同步性及其可比性可以成为区分电缆内部信号与外部信号的有力判据。论文最后还介绍了对于个别维修后作为重点监护的接头,加装了几套短时性或临时性的局放在线监测装置实施短期连续实时监测,为电缆线路的安全运行和维护管理提供有力的数据支持。     

次声信号数据采集系统的研制

次声信号数据采集系统所采集的是0-20Hz的次声信号。该信号通过传声器转换为相应的电压信号。计算机实时采集、处理次声信号,分析次声信号的各主要频率成分和强度大小、对分析结果进行图形显示,曲线自动输出,并生长、打印最终结果。     

Reliability of the Parabola Approximation Method in Heart Rate Variability Analysis Using Low-Sampling-Rate Photoplethysmography

Photoplethysmographic signals are useful for heart rate variability analysis in practical ambulatory applications. While reducing the sampling rate of signals is an important consideration for modern wearable devices that enable 24/7 continuous monitoring, there have not been many studies that have investigated how to compensate the low timing resolution of low-sampling-rate signals for accurate heart rate variability analysis. In this study, we utilized the parabola approximation method and measured it against the conventional cubic spline interpolation method for the time, frequency, and nonlinear domain variables of heart rate variability. For each parameter, the intra-class correlation, standard error of measurement, Bland-Altman 95% limits of agreement and root mean squared relative error were presented. Also, elapsed time taken to compute each interpolation algorithm was investigated. The results indicated that parabola approximation is a simple, fast, and accurate algorithm-based method for compensating the low timing resolution of pulse beat intervals. In addition, the method showed comparable performance with the conventional cubic spline interpolation method. Even though the absolute value of the heart rate variability variables calculated using a signal sampled at 20 Hz were not exactly matched with those calculated using a reference signal sampled at 250 Hz, the parabola approximation method remains a good interpolation method for assessing trends in HRV measurements for low-power wearable applications.     

Muscle Fatigue Detection in EMG Using Time–Frequency Methods, ICA and Neural Networks

The electromyography (EMG) signals give information about different features of muscle function. Real-time measurements of EMG have been used to observe the dissociation between the electrical and mechanical measures that occurs with fatigue. The purpose of this study was to detect fatigue of biceps brachia muscle using time–frequency methods and independent component analysis (ICA). In order to realize this aim, EMG activity obtained from activated muscle during a phasic voluntary movement was recorded for 14 healthy young persons and EMG signals were observed in time–frequency domain for determination of fatigue. Time–frequency methods are used for the processing of signals that are non-stationary and time varying. The EMG contains transient signals related to muscle activity. The proposed method for the detection of muscle fatigue is automated by using artificial neural networks (ANN). The results show that ANN with ICA separates EMG signals from fresh and fatigued muscles, hence providing a visualization of the onset of fatigue over time. The system is adaptable to different subjects and conditions since the techniques used are not subject or workload regime specific.     

适用于生物医学信号功率谱分析的计算机实用程序

This paper presents a useful program for the power spectra analysis of biomedical signals on a microcomputer. The frequency spectra to show the allocation of frequency were calculated from the acquired biomedical signal via a window algorithm and the real signal special handling. The frequency spectra became normalized power spectra through algorithm and could be displayed on a monitor or printer in the mode of histogram. We have got good results using this program to compute the power spectra of phrenic nerve discharges from the rabbit.     

Current Technologies of Synthetic Biosensors for Disease Detection: Design,Classification and Future Perspectives

Synthetic biology aims to endow living cells with new functions by incorporating functional gene networks into them. By overexpressing, blocking and rewiring native gene pathways, synthetic biologists have harnessed this promising technology to reprogram cells to perform diverse tasks such as drug discovery, biopharmaceutical manufacturing, gene therapy and tissue engineering, etc. In this review, we focus on current technologies of synthetic biosensors for disease detection. We start with the design principle of synthetic biosensors. Then we move towards the characteristics of simple synthetic biosensors, which can respond to a single input signal, and complex synthetic biosensors including Boolean gate biosensors, cascade biosensors, time-delay biosensors, oscillator biosensors and hysteretic biosensors, which can respond to more than two input signals and perform complex tasks. Synthetic biosensor has showed great potential in disease detection, but it is still in its infancy stage. More efforts should be made in identifying and constructing clinically relevant regulation systems. Computational tools are also needed in the design process in order to guarantee the precision of the synthetic biosensor. The ultimate goal of a synthetic biosensor is to act as a therapeutic sensor-effector device that connects diagnostic input with therapeutic output and therefore provides all-in-one diagnostic and therapeutic solutions for future gene- and cell-based therapies.