Analysis of pulse-wave propagation characteristics in abdominal aortic sclerosis disease

In this work,a bidirectional fluid-structure coupling finite element analysis model of the abdominal aorta was established,with the various vascular elastic modulus as the main parameters for atherosclerosis,taking into consideration blood's dynamic viscosity and compressibility.Pressure and velocity pulse-wave propagation were investigated through the application of a full-coupling analysis algorithm.The effect of atherosclerosis degree on the propagation characteristics of pulse waves in the bifurcated abdominal aorta was quantitatively analyzed.Arterial bifurcation can cause substantial attenuation on the peak of pressure pulse waveform and an increase in wave velocity during the cardiac cycle.The elastic modulus and bifurcation properties of the arterial wall directly affected the peak value and wave propagation velocity of the pressure pulse wave.The preliminary results of this work will be crucial in guiding the evolution of the pressure pulse wave and the initial diagnosis of atherosclerotic disease through the waveform.

Cardiovascular Diseases Detecting via Pulse Analysis

In this research, we have performed pulse analysis on the data of 127 subjects collected from Department of Cardiology at Shandong Provincial Hospital in China. By taking the first and third derivatives of an entire pulse wave, we have firstly identified the locations of wave foot, systolic peak, and reflected point. Then we calculated Reverse Shoulder Index (RSI) and Ratio of Distance of the evaluated subjects, and correlated them to age, the history of hypertension, and different cardiovascular diseases of the subjects.

APPLICATION OF TRANSIENT ELECTROMAGNETIC PULSE IN DETECTING SUBSURFACE TARGETS

A basic scheme for detecting subsurface targets with nanosecond EM pulse and anespecially developed high quality travelling-wave antenna are described.The antenna is a sortof sector antenna with structure of three layers,which possesses higher radiation efficiency andbetter travelling-wave properties.A fine resolution graphic system and a high speed display areemployed in terminal processing.Metal pipes buried about 1 m under the earth can be detectedand clearly displayed.High resolution and short processing time of the system,compared withother similar devices,make it suitable for engineering use.

Acoustic wave detection of laser shock peening

In order to overcome the existing disadvantages of offline laser shock peening detection methods, an online detection method based on acoustic wave signals energy is provided. During the laser shock peening, an acoustic emission sen- sor at a defined position is used to collect the acoustic wave signals that propagate in the air. The acoustic wave signal is sampled, stored, digitally filtered and analyzed by the online laser shock peening detection system. Then the system gets the acoustic wave signal energy to measure the quality of the laser shock peening by establishing the correspondence between the acoustic wave signal energy and the laser pulse energy. The surface residual stresses of the samples are measured by X-ray stress analysis instrument to verify the reliability. The results show that both the surface residual stress and acoustic wave signal energy are increased with the laser pulse energy, and their growth trends are consistent. Finally, the empirical formula between the surface residual stress and the acoustic wave signal energy is established by the cubic equation fitting, which will provide a theoretical basis for the real-time online detection of laser shock peening.

NUMERICAL SIMULATION OF THE TEMPERATURE FIELD IN A SOLDER BALL UNDER PULSED LASER AND ITS EFFECT ON THE VIBRATION OF THE SOLDER

The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat source. Finite element method is applied to analyzed the temperature field in the solder ball, and experi- ment is conducted to test the vibration. the results show that,that, the temperature field flucturates with the same frequency as that of the laser pulse, which in turn causes a forced vibration of the same frequency in the liquid solder ball.

Noninvasive method for determining blood pressure and contours of arterial and volume pulses

A noninvasive method for monitoring blood pressure, based on the principles established by Riva-Rocci and Korotkoff (K), is described;it furnishes, after a single compression-deflation cycle of the arm-encircling cuff, values of sys-tolic and diastolic blood pressures as well as the contours of the brachial arterial pulse and the corresponding volume pulse. K-sounds are detected by a single microphone situated in the cubital fossa, and the time-varying cuff pressure P(t) is read by a piezoresistive pressure sensor. The behavior of P(t) during deflation is resolved into two parts, P(t)=p(t)+b(t);p is a train of posi-tive going pulses (arising from arterial pulsa-tions), whereas b is a slowly changing baseline. Noise pulses in the microphone output are re-jected by using the observation that the first few K-sounds are emitted when p is close to a maxi-mum, and the last few when dp/dt is close to a maximum. The performance of the instrument is illustrated by showing how it copes with ambi-ent noise and involuntary manual perturbations of P, and by presenting contours of various pulses.

Electron acceleration by tightly focused radially polarized few-cycle laser pulses

Within the framework of plane-wave angular spectrum analysis of the electromagnetic field structure, a solution valid for tightly focused radially polarized few-cycle laser pulses propagating in vacuum is presented. The resulting field distribution is significantly different from that based on the paraxial approximation for pulses with either small or large beam diameters. We compare the electron accelerations obtained with the two solutions and find that the energy gain obtained with our new solution is usually much larger than that with the paraxial approximation solution.

Design of High-speed Sampling System in Pulse Laser Application

In measurement system by means of pulse laser, such as plasma measuring, laser ranging, the amplitude of echoed laser wave is very weak and difficult to detect by traditional analog electronic technology. A digital high speed data acquisition and processing system was designed to meet the accuracy requirement. It adopted high speed AD chip and advantage FPGA chip as core unit. Experiment results have verified this system can reach to 1GHz sample rate and can catch weak echo wave effectively and the measuring accuracy is improved markedly.

Four-wave mixing model solutions for polarization control of terahertz pulse generated by a two-color laser field in air

A four-wave mixing （FWM） model is used to analyze the polarization control of terahertz （THz） pulse generated by a two-color laser field in air. The analytic formula for the THz intensity varying with the THz polarizer angle, and the relative phase between the two pulses, are obtained. The corresponding numerical results agree well with both numerical result obtained from a quantum model and measured data reported. Moreover, possible phenomena are predicted for variables not found in other experiments. Compared with the quantum model, the FWM model gives analytic formulas and clear physical pictures, and has the advantage of efficient computing time.

关于脉搏波谐波产生机理、分布特性及相关心率检测方法的研究

传统中医认为人体特定的脉搏波频率特性与其脏腑的功能有关。为了研究和阐明脉搏波谐波的产生机理和分布特征,通过对理想脉搏波的离散傅里叶变换进行理论研究,并将真实脉搏波的频谱与理想脉搏波频谱进行比较和分析,验证了真实脉搏波谐波现象存在的合理性。在此基础上,文章提出了一种基于脉搏波谐波特性的更为稳定的心率计算方法。该研究为脉搏波的频域分析奠定了理论基础,对各种类似的准周期信号的分析也具有一定的应用和参考价值。

变压器内部电弧故障快速检测方法研究与对比

变压器内部短路电弧故障是变压器最危险、最严重的故障,极有可能造成变压器油箱的形变和破裂,乃至变压器油的燃烧与爆炸,对人员生命安全、变电站财产安全、电网运行安全都造成了严重威胁。实现变压器内部短路电弧故障的快速检测有利于及时发出断路器分闸信号,从而缩短电弧燃弧时间,减小电弧能量,降低燃爆可能性。为寻找适用于电弧故障快速检测的信号及特征,首先搭建了基于电容电感串联谐振的油中工频大电流电弧实验平台,并实现了油中工频电弧的电压、电流、压力波、光、电磁脉冲、气泡形态等关键电弧特性的测量;发现压力波存在前期快速振荡-后期持续上升两阶段,光信号存在间隔约10 ms的脉冲,电弧电流过零点时必定会产生电磁脉冲,上述压力波、光和电磁脉冲3种信号及其特性有望应用于变压器内部短路电弧故障的快速检测;最后对比了这3种故障检测方法的优缺点,并指出这些方法在工程实际应用前急需进一步解决的问题。

基于光电容积脉搏波描记法的柔性血压传感器标定方法研究

基于光电容积脉搏波描记法(Photo Plethysmo Graphy,PPG)的柔性传感器可进行心率(Heart Rate,HR)和血压(Blood Pressure,BP)检测,但是对其检测结果的标定报道甚少.据此,本文提出一种基于模拟血液循环的反射式PPG心率检测和血压标定系统.以蠕动泵来产生脉动流,通过调节其转速的大小来控制模拟血液输送的频率和压力,从而引起弹性乳胶管内模拟血液体积的变化,而改变反射光的信号周期与强度,贴近于人体脉搏测量过程的实际场景.该系统心率检测误差均值为0.27778,95%一致性界限为(-2.59562,3.15117),所测收缩压(Systolic Blood Pressure,SBP)和舒张压(Diastolic Blood Pressure,DBP)的拟合优度分别为0.97185和0.98111.经标定后的柔性PPG传感器对4名志愿者检测的SBP和DBP的平均偏差(Mean Deviation,MD)±标准差(Standard Deviation,SD)均值分别为(1.21±2.16)mmHg和(0.76±2.02)mmHg,均符合且远小于美国医疗仪器促进协会(Association for the Advancement of Medical Instrumentation,AAMI)所制定的衡量血压计精度的标准指标(5±8)mmHg.结果表明,该系统能够准确高效地标定柔性PPG传感器,为实现便携式可穿戴设备的精准血压检测提供标定基础.

基于谐波分析法观察抑郁症患者脑网络形态学改变

目的评估基于谐波分析法观察抑郁症(DD)患者脑网络形态学改变的可行性。方法对55例DD患者(DD组)和46名正常对照者(NC组)采集全脑3D高分辨T1WI,利用FreeSurfer 5.3.0工具构建脑网络6种形态学特征,包括脑区顶点数、表面积、灰质体积、平均皮层厚度、高斯曲率及折叠指数,以拉普拉斯矩阵特征分解获得公共谐波;比较组间不同形态学特征所在谐波能量及脑区灰质体积。结果组间不同形态学特征总谐波能量差异均无统计学意义(P均>0.05)。组间特定谐波能量差异有统计学意义(P均<0.05),主要包括脑区顶点数谐波能量差异为第2、6、15、44、57谐波,表面积谐波能量差异为第2、6、16、57谐波,灰质体积谐波能量差异为第2、12、13、15、57谐波,平均皮层厚度谐波能量差异为第2、19、35、36、44谐波,高斯曲率谐波能量差异为第34、40、54、57谐波,以及折叠指数谐波能量差异为第5、16、21、57谐波。DD组左脑区颞横皮质区域灰质体积显著大于NC组(t=2.900,P=0.004)。结论谐波分析法可用于观察DD患者脑网络形态学改变。

载人离心机训练用高精度耳脉搏波生理信号检测装置的设计与实现

目的:设计一种载人离心机训练用高精度耳脉搏波生理信号检测装置,以解决载人离心机训练时飞行员耳脉搏波信号无法准确计量、校准的问题。方法:高精度耳脉搏波生理信号检测装置由耳脉搏波采集传感器、信号采集控制单元和上位机信号处理模块组成。其中,耳脉搏波采集传感器外形为耳夹样式,主要由外壳、内壳和弹性钢片组成;信号采集控制单元硬件由电源模块、光源恒压模块、信号采集模块、主控模块和数据传输模块组成,软件部分在嵌入式系统上开发实现;上位机信号处理模块将信号处理划分为信号预处理和脉搏波信号监测显示2个阶段。采用生理电信号检定仪对该装置检测的耳脉搏波信号进行测试,以验证该装置的检测性能;采用该装置在不同载荷下进行载人离心机训练试验,以验证该装置的有效性和稳定性。结果:该装置检测的电压测量误差、幅频特性和共模抑制比均在JJG 760—2003《心电监护仪检定规程》和JJG 954—2019《数字脑电图仪检定规程》允许的范围内;该装置能够实时检测载人离心机训练时飞行员的耳脉搏波信号,且受运动干扰较小,信号质量稳定。结论:采用该装置可以准确得到载人离心机训练时飞行员的耳脉搏波波幅的变化,能够有效反映飞行员在正加速度作用下的脑血流量变化。

光电容积脉搏波技术在可穿戴医疗设备中的应用及其未来发展

光电容积脉搏波(Photoplethysmography,PPG)技术,作为一种非侵入式的生理参数监测方法,在心率、血氧饱和度以及其他生理指标的实时监测中已广泛应用。随着可穿戴技术的快速发展,PPG技术在医疗设备领域呈现出广阔的应用前景。本文详细讨论了PPG技术的基本原理、在可穿戴医疗设备中的应用现状及面临的挑战,同时探索了技术的未来发展方向。

肱踝脉搏波传导速度的影响因素及其与全身炎症反应指数的相关性分析

目的探讨全身炎症反应指数(SIRI)与肱踝脉搏波传导速度(BaPWV)的相关性及临床价值。方法于2018年1月至2019年12月,在闽东自然人群通过整体抽样收集共212名志愿者的临床相关资料,包括临床基线资料,空腹抽血检验血常规、血生化,测量BaPWV。以BaPWV值1400m/s为界分为BaPWV正常组及升高组。通过单因素分析及Pearson检验分析两组数据,差异有统计学意义的变量,纳入多因素logistic回归分析,评估SIRI与BaPWV这两个指标之间的相关性,并分析BaPWV的影响因素。结果BaPWV升高组的年龄、高血压、吸烟情况、收缩压、舒张压、总胆固醇、甘油三酯、低密度脂蛋白、白细胞、中性粒细胞、空腹血糖、同型半胱氨酸、SIRI水高于BaPWV正常组,差异有统计学意义(P<0.05),SIRI与BaPWV呈正相关(r=0.357,P<0.001)。多因素logistic回归分析结果显示,年龄(β=0.110,OR=1.116,95%CI:1.069~1.165,P<0.001)、收缩压(β=0.034,OR=1.034,95%CI:1.001~1.068,P=0.041)、舒张压(β=0.083,OR=1.086,95%CI:1.033~1.142,P=0.001)是BaPWV增高的独立影响因素,而SIRI并非BaPWV增高的独立影响因素。结论SIRI可能与动脉硬化发展过程中具有一定相关性,但并非起决定作用,临床上应更多关注年龄、收缩压、舒张压这些BaPWV增高独立影响因素,并及时采取相应干预措施,以便对动脉硬化风险更好临床管理。

血清MMP2/TIMP2比值与老年2型糖尿病患者并发AS的相关性分析

目的探讨血清基质金属蛋白酶-2/金属蛋白酶组织抑制因子-2(MMP2/TIMP2)比值与老年2型糖尿病(T2DM)患者并发主动脉硬化(AS)之间的关系。方法回顾性分析2022年1月至2023年4月万宁市人民医院收治的180例初次诊断为T2DM的老年患者的临床资料,并根据是否并发AS[颈动脉-股动脉脉搏波传导速度(cfPWV)>10 m/s]分为AS组(n=69)和非AS组(n=111)。另选取同时期来院体检健康者采用倾向性评分法匹配90例为对照组。比较3组对象的一般资料、实验室指标以及血清MMP2、TIMP2水平和MMP2/TIMP2比值。采用Spearman相关分析探究老年T2DM患者cfPWV与各项指标的相关性。采用多因素logistic回归模型分析,老年T2DM患者并发AS的影响因素。绘制受试者工作特征(ROC)曲线,分析并比较MMP2/TIMP2比值与多指标联合检测对老年T2DM患者并发AS的诊断价值。结果非AS组稳态模型胰岛素抵抗指数(HOMA-IR)、血清三酰甘油(TG)、MMP2水平及MMP2/TIMP2比值高于对照组,血清TIMP2水平低于对照组,差异有统计学意义(P<0.05)。AS组年龄、合并高血压比例高于非AS组(P<0.05)。AS组HOMA-IR、血清TG、MMP2水平及MMP2/TIMP2比值高于对照组和非AS组,血清TIMP2水平低于对照组和非AS组,差异均有统计学意义(P<0.05)。相关性分析结果显示,非AS组患者的cfPWV与HOMA-IR、TC、LDL-C、MMP2、MMP2/TIMP2比值呈正相关(r=0.217、0.264、0.216、0.197、0.703,P<0.05),与TIMP2呈负相关(r=-0.524,P<0.01);AS组患者cfPWV与MMP2、MMP2/TIMP2比值呈正相关(r=0.659、0.857,P<0.01),与TIMP2呈负相关(r=-0.532,P<0.01)。logistic回归分析显示,年龄增长(OR=1.108,95%CI:1.022~1.201,P=0.012)、高血压病(OR=2.877,95%CI:1.174~7.051,P=0.021)及MMP2/TIMP2比值升高(OR=5.147,95%CI:2.392~11.074,P<0.001)是老年T2DM患者并发AS的的独立危险因素。ROC曲线分析结果显示,MMP2/TIMP2比值及多指标联合检测诊断老年T2DM患者并发AS的曲线下面积分别为0.850(95%CI:0.789~0.899,P<0.01)和0.886(95%CI:0.831~0.929,P<0.01),灵敏度分别为73.91%、82.61%,特异度分别为89.19%、82.88%,约登指数分别为0.631、0.655。多指标联合检测的诊断效能明显大于MMP2/TIMP2比值,差异具有统计学意义(Z=2.233,P=0.026)。MMP2/TIMP2比值诊断老年T2DM患者并发AS的最佳截断值为3.23。结论MMP2/TIMP2比值升高为老年T2DM患者并发AS的独立危险因素,对老年T2DM并发AS的诊断有辅助价值,多指标联合检测可提高诊断效能。

甘油三酯-葡萄糖指数与颈动脉结构和弹性功能关联性及中介效应

目的探讨一般成年人群甘油三酯-葡萄糖指数(triglyceride-glucose index,TyG)与颈动脉结构和弹性功能的关系。方法选取2021年6月~2021年12月期间在唐都医院进行年度体检的健康志愿者的临床超声资料,进行横断面研究,共纳入志愿者594例。根据TyG指数水平的三分位数范围分为3组:T1组(4.24±0.10),T2组(4.45±0.06),T3组(4.71±0.11),各组人数均为198。通过多元线性模型估计TyG指数,颈动脉内中膜厚度(carotid intima-media thickness,CIMT)与脉搏波传导速度(pulse wave velocity,PWV)之间的关系。采用中介效应分析身体质量指数(body mass index,BMI)、血压、血糖和血脂指标在TyG指数与CIMT及PWV关联性中的中介作用。结果随着TyG指数水平的升高,调查对象各项数据依组逐次变化,T1、T2与T3组吸烟的比例逐次升高并有统计学差异,相邻组及跨组比较均P<0.05;年龄、女性比例、BMI、总胆固醇、低密度脂蛋白胆固醇、甘油三酯、空腹血糖、饮酒比例、CIMT与PWV逐渐增高,高密度脂蛋白胆固醇逐渐减低,相邻组及跨组比较均P<0.01。多元线性回归分析发现,调整协变量后,TyG指数每增加1个单位,CIMT增加0.54μm(95%CI:0.13~0.64;P<0.01),PWV增加0.28 m/s(95%CI:0.20~0.37;P<0.01)。中介效应分析发现,SBP以间接介导的方式对PWV产生正向影响,其中介效应占比为18.2%。结论TyG指数是正常成年人群CIMT及PWV的独立危险因素。TyG指数通过SBP介导以间接方式与PWV呈正相关。

基于脉搏波信号和血管弹性腔模型的动脉血压连续测量方法

目的为满足健康监护中的连续测量血压的要求,研究并实现一种基于脉搏波信号和血管弹性腔模型的动脉血压拟合计算方法。方法利用自制的穿戴式人体生理参数监测系统收集测试对象的脉搏波信号、心电信号以及血压数据。根据心电信号与脉搏波信号的时间关系,推导出收缩压和脉搏波传导时间的回归分析方程,而舒张压的测量,则是通过脉搏波的波形系数分析以及血管单弹性腔模型的参数计算完成。结果试验结果表明,该方法血压测量结果的平均偏差和标准偏差为(0.51±0.74)kPa([384±5.54)mmHg],达到了美国医疗仪器促进协会建议的(0.665±1.064)kPa([5±8)mmHg]标准。结论结合脉搏波信号和弹性腔模型可以估算人体血压值,为连续血压测量提供了新的实现方法。

激光参数及激光超声探测方法对超声信号影响

文中通过激光超声激发过程理论模型,获得激光超声信号的波形特点,并分析相关参数对激发超声信号的影响。应用两种不同的激光超声探测方法对激光超声信号进行探测,即分别采用超声探头和基于双波混合干涉的光学探测方式搭建两种实验装置。实验针对入射激光参数对激发超声信号的影响及两种探测方法获得激光超声信号的特点进行分析。通过实验验证了理论分析结果,得出入射激光参数会影响激发超声的幅度,而基于双波混合干涉的光学探测方式可以获得更为完整的超声波形信息。