Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

Nitrogen monoxide vector of ultrasonic atomizing inhalation improves vertebro-basilar artery insufficiency Hemodynamic changes are detected by transcranial Doppler test

BACKGROUND： Latest researches at home and abroad indicate that glycerol trinitrate plays its function because it can metabolize into nitrogen monoxide （NO） in vivo. OBJECTIVE： To study the therapeutic effects of NO vector of ultrasonic atomizing inhalation on vertebro-basilar artery insufficiency （VBI） through transcranial Doppler （TCD） detection and serum NO content and indirect effect of TCD on cerebral blood flow changes. DESIGN： Randomized grouping and controlled clinical study. SETTING： Department of Neurology, the Fourth People＇s Hospital of Jinan. PARTICIPANTS： A total of 130 patients who were diagnosed as VBI were selected from Department of Neurology, the Fourth People＇s Hospital of Jinan from December 2001 to December 2005. The involved inpatients were checked by CT and MRI, and met the VBI diagnostic standard enacted by the Fourth National Academic Meeting of Cerebrovascular Disease in 1995. All patients and their relatives provided the confumed consent. They were randomly divided into low-dose treatment group （n =60）, high-lose treatment group （n =30） and control group （n =40）. METHODS： Patients in the low-dose and high-dose treatment groups were given ultrasonic atomizing inhalation of 3 mg and 5 mg glycerol trinitrate, respectively, for 20 minutes, once a day. In addition, ligustrazine and energy mixture were used once a day for three days in a course. Cases in the control group were only given ligustrazine and energy mixture. All selected cases accepted TCD, blood NO content was checked at the time of beginning, after the first time and after a period of treatment. According to the TCD test, VBI patients were divided into two groups （high-low flow velocity）. The vertebral artery （VA） and basal artery （BA） of left or right sides were detected by 2 Hz detector via occipital window. MAIN OUTCOME MEASURES： ①Blood flow velocity of systolic phase, blood flow velocity of diastole phase and vascular resistance in left and right VA and BA detected by using TCD before treatment, after treatment for one course; ②content of serum NO indirectly measured by using nitric acid disoxidation technique. RESULTS： All 130 VBI patients were involved in the final analysis. ①Changes of hemodynamic indexes： Systolic phase of VA and diastole phase of BA were higher in low-dose treatment group than that in the control group after first treatment, and there was significant difference （P 〈 0.05）; meanwhile, systolic phase and diastole phase of VA and systolic phase of BA were also higher in treatment group than that in the control group after one course （P 〈 0.05）. However, both systolic phase and diastole phase of VA and BA were lower in high-dose treatment group than that in the control group after first treatment and one course, and there was significant difference （P 〈 0.05）. ②Content of serum NO： After first treatment, there was no significant difference between low-dose treatment group and high-dose treatment group （P 〉 0.05）; but both groups were higher than control group, and there was significant difference （P 〈 0.05, 0.01）. CONCLUSION： NO vector of ultrasonic atomizing inhalation can improve VBI so as to improve cerebral blood-supply state.

APPROACH OF IMPROVING PRECISION IN ULTRASONIC DOPPLER BLOODSTREAM SPEED MEASUREMENT BY CHAOS-BASED FREQUENCY DETECTING

It is critical for cerebral vascular disease diagnosis through Doppler to detect the maximum and the minimum of the carotid blood flow speed accurately. A kind of Duffing system under an external periodic power with dump is introduced in the letter, numerical analysis is carried out by four-order Runge-Kutta method. An oscillator array is designed according to the frequency of the ultrasonic wave. When the external signals are inputted, computational algorithm is used to scan the array in turn and analyze the result, and the frequency can be determined. Based on the methods above, detecting the carotid blood flow speed accurately is realized. The Signal-to-Noise Ratio (SNR) of-20.23dB is obtained by the result of experiments. In conclusion, the SNR has been improved and the precision of the measured bloodstream speed has been increased, which can be 0.069% to 0.13%.

Simultaneous measurement of velocity profile and liquid film thickness in horizontal gas–liquid slug flow by using ultrasonic Doppler method

Horizontal gas-liquid two-phase flows widely exist in chemical engineering,oil/gas production and other important industrial processes.Slug flow pattern is the main form of horizontal gas-liquid flows and characterized by intermittent motion of film region and slug region.This work aims to develop the ultrasonic Doppler method to realize the simultaneous measurement of the velocity profile and liquid film thickness of slug flow.A single-frequency single-channel transducer is adopted in the design of the field-programmable gate array based ultrasonic Doppler system.A multiple echo repetition technology is used to improve the temporal-spatial resolution for the velocity profile.An experiment of horizontal gas-liquid two-phase flow is implemented in an acrylic pipe with an inner diameter of 20 mm.Considering the aerated characteristics of the liquid slug,slug flow is divided into low-aerated slug flow,high-aerated slug flow and pseudo slug flow.The temporal-spatial velocity distributions of the three kinds of slug flows are reconstructed by using the ultrasonic velocity profile measurement.The evolution characteristics of the average velocity profile in slug flows are investigated.A novel method is proposed to derive the liquid film thickness based on the instantaneous velocity profile.The liquid film thickness can be effectively measured by detecting the position and the size of the bubbles nearly below the elongated gas bubble.Compared with the time of flight method,the film thickness measured by the Doppler system shows a higher accuracy as a bubble layer occurs in the film region.The effect of the gas distribution on the film thickness is uncovered in three kinds of slug flows.

A gas kick early detection method outside riser based on Doppler ultrasonic wave during deepwater drilling

The feasibility of gas kick early detection outside the riser was analyzed based on gas-liquid multiphase flow theory.Then an experimental platform for gas kick early detection based on Doppler ultrasonic wave was established and the propagation experiments in two-phase flow of gas-water(sucrose solutions)were conducted.The time and frequency domains of the Doppler ultrasonic wave signals during the experiments were analyzed.The results show that:(1)No matter the pump was on or off,the detected average Doppler ultrasonic signal voltage increased first and then decreased with the increase of the gas void fraction,and had a quadratic function relation with gas void fraction,so the average voltage change of the monitored signals can be used to deduce the approximate gas void fraction.The Doppler ultrasonic wave signal voltage was significantly reduced in magnitude and variation in the solution with higher viscosity,and the viscosity has stronger impact on the magnitude of signal than density.(2)When the pump was stopped,the Doppler shift increased with the increase of gas void fraction,and the two showed a nearly linear relation,so the detected amount of Doppler shift can reflect the variation of gas void fraction quantitatively.When the pump was on,the sound energy produced by frequency converter had a more significant impact on amplitude spectrum than gas void fraction,so it is impossible to determine whether gas kick occurs by frequency domain signal analysis.(3)This method is a non-contact measurement,with no contact with the drilling fluid and no disruption to the drilling operation.It can quantitatively characterize the gas void fraction according to the change of Doppler ultrasonic signal,enabling earlier detection of gas kick.

Enhancement of the corrosion resistance of the Mg alloy ZW61 by dual-frequency ultrasonic vibration

Ultrasonic vibration was introduced into the casting of quasicrystal-reinforced magnesium alloy ZW61.The microstructure,mechanical properties,and corrosion resistance were studied.The dual-frequency ultrasonic field(DUF)treatment reduced the α-Mg grain size from 502μm to 69μm,and the aggregated lamellar I-phase was refined into tiny dot-like shapes with a smaller area fraction.Static corrosion and electrochemical tests indicated that DUF decreased the corrosion rate from 10 mm·y^(-1)to 3mm·y^(-1)with a denser protective oxide film.DUF not only significantly enlarged the effective cavitation area but also reduced the dependence of transient cavitation on the initial bubble radius.The ratio R_(max)^(3)/t_(c) was used to qualitatively characterize the cavitation strength,and cavitation dynamics calculations indicated that DUF had higher cavitation strength compared to single-frequency ultrasonic field(SUF).An equation for corrosion rate versus microstructural parameters(grain size,second phase fraction,potential difference)was developed,which could well predict the corrosion rate of magnesium alloy ZW61 without and with different ultrasonic vibrations.

Three-Dimensional Velocity Distribution Measurement Using Ultrasonic Velocity Profiler with Developed Transducer

This study describes an ultrasonic velocity profiler that uses a new ultrasonic array transducer with unique 5-element configuration, with all five elements acting as transmitters and four elements as receivers. The receivers are designed to reduce the amount of uncertainty. As the fluid moves through this setup, four Doppler frequencies are obtained. The multi-dimensional velocity information along the measurement line can be reconstructed. The transducer has a compact geometry suitable for a wide range of applications, including narrow flow areas. The transducer’s basic frequency and sound pressure are selected and evaluated to be compatible with the application. First, to confirm the measurement ability, the measurement of the developed system in two-dimensional flow is validated by comparing it to the theoretical data. The uncertainty of measurement was within 15%. Second, the three-dimensional measurement in turbulent and swirling flow is proved experimentally to check the applicability of the proposed technique.

眼部超声Doppler血流计的研制

眼部正常的血液供应是维持眼部组织正常生理功能的基础。该文介绍了一种无创检测眼部血流速度瞬时相对变化和眼部血流状况的超声Doppler血流计,该血流计由超声波信号发生器、超声波换能器、放大器、混频器、A/D转换器和微型计算机等组成,可实时、在体、无创检测眼部血流速度和血容量的相对变化,具有结构简单、使用方便等特点。

糖尿病患者颅外段脑动脉粥样硬化的彩色超声Doppler检测及临床意义

目的 探讨2型糖尿病患者颅外段脑动脉粥样硬化的彩色超声Doppler变化，对缺血性脑病，特别是脑梗塞的及早诊断提供重要依据。方法 应用二维声像图，彩色血流显像及频谱Doppler对80例2型糖尿病惠者和100例健康对照组进行颈动脉．椎动脉检测．连接超声工作站，将信息收集贮存以便分析，结果 糖尿病组超声检出粥样硬化斑者63例，斑块发生率为79％。非糖尿病组检出斑块14例，斑块发生率为14％。根据声像图特点，斑块分为四型，软斑为脑梗塞的危险信号。斑块与脑梗塞的侧向分辨力为93％。两组斑块发生率经X^2检验，有显著性差别（P〈0．005）。结论 颅外段脑动脉粥样硬化是糖尿病的重要井发症之一，彩色超声显像及Doppler可清晰显示硬化的程度、斑块大小，性质、部位、血流动力学参数及Doppler形态的改变等，为临床预测脑梗塞提供诊断依据。

SOURCE OF DOPPLER EFFECT IN BLOOD FLOW

Ordinary the Doppler effect in blood now was explained with thevariation of period or wavelenth. From vector compositing, the Doppler errect inblood flow is now explained with the variation of propergation velocity of ultrasound in different coordinates systems. The basic rormula of Doppler frequencyshift is derived' The experimental results are discussed.

SY-TI型调制脉冲超声Doppler血流检测仪的研制

1 仪器组成及工作原理1.1 仪器组成本文所用调制型脉冲超声Doppler血流检测仪主要由三部分组成,即主机部分、记录部分及Doppler信号处理与频谱分析部分。其主要技术指标是,工作频率:5.0±0.000002MHz,辐射声强:连续正弦波小于8.0mW/cm^2,调制脉冲波小于2.0mW/cm^2;调制脉冲频率,为7.5kHz;空间采样尺寸,1.0～15.0mm可调;空间采样分辨率,1.5～2.0mm;可测深度,0.0～8.0±0.1cm;诊断深度,连续波0.0～3.0cm,脉冲波0.4～3.0cm;

多普勒超声波技术在河道断面流速流量监测中的应用

基于多普勒超声波技术的基本原理,分析其在河道断面流速流量监测中的具体应用,包括多点流速剖线测量、走航式流量测量、湍流监测。通过一条典型河流的应用实例,验证了该技术在复杂河道条件下的有效性和高效性。结果表明,多普勒超声波技术为水文过程研究和河流管理提供了重要的数据支持。

彩色多普勒超声在子宫内膜息肉患者中的诊断效果及超声征象

目的探讨彩色多普勒超声在子宫内膜息肉患者中的诊断效果及超声征象。方法选择2021年6月—2023年2月疑似子宫内膜息肉患者135例为对象,所有患者均开展两种形式的检查,即在本次调研中重点研究经腹部彩色多普勒超声和经阴道超声检查,以宫腔镜下定位活组织病理检查结果作为“金标准”,分析经腹部彩色多普勒超声和经阴道超声在子宫内膜息肉患者中的诊断效果,比较患者彩色多普勒超声征象。结果135例疑似经子宫内膜息肉患者经“金标准”检查阳性96例,阳性率为71.11%。经腹联合经阴道超声检查用于子宫内膜息肉患者中诊断准确度、灵敏度、特异度、阳性及阴性预测值高于单一检查的患者(均P<0.05);金标准阳性患者子宫肌层与内膜分界模糊、病灶内部回声不均匀、血流丰富病例数多于阴性患者(P<0.05);RI和PI水平均低于阴性患者(均P<0.05)。结论经腹部彩色多普勒超声和经阴道超声检查用于子宫内膜息肉患者中具有较高检出率,二者联合检查能提高诊断效能,且患者具有典型的超声征象,能指导临床诊疗。

Experimental Study of Liquid Metal Flow for the Development of a Contact-Less Control Technique

The article presents an experimental study on the flow of an eutectic gallium alloy in a cylindrical cell,which is placed in an alternating magnetic field.The magnetic field is generated by a coil connected to an alternating current source.The coil is located at a fixed height in such a way that its plane is perpendicular to the gravity vector,which in turn is parallel to the axis of the cylinder.The position of the cylinder can vary in height with respect to the coil.The forced flow of the considered electrically conductive liquid is generated due to the action of the localized electromagnetic force.It is assumed that under the action of the alternating magnetic field,the liquid is heated uniformly,and the resulting heat is quickly absorbed by the forced flow,so that liquid free convection can be neglected.The experiment is carried out using an ultrasonic Doppler anemometer.One transducer is installed in the axially located cylinder sluice and the other transducer is placed in the near-wall region.According to the results,a velocity profile,corresponding to a two-tori flow pattern can be hardly obtained in the low frequency range of the power supply.However,this is possible in the high frequency range.The average velocity profiles depend essentially on the location of the coil relative to the cell.The spectral analysis of velocity signals shows that the amplitude of the velocity pulsations is comparable to the average value of the flow velocity.Such experimental results and their verification through comparison with numerical calculations are intended to support the development of new methods for reducing the intensity of vortex flows during the electromagnetic separation of impurities through an electromagnetic induction mechanism(able to produce an electromotive force that displaces particles).

彩色多普勒血流成像联合超声弹性成像对乳腺良恶性结节的鉴别诊断价值

目的探讨彩色多普勒血流成像(CDFI)联合超声弹性成像(UE)检查对乳腺良恶性结节的鉴别诊断价值。方法80例乳腺结节患者(共92个结节)均进行CDFI以及UE检查,以手术病理检查结果作为诊断“金标准”,分析CDFI、UE单独及联合检查对乳腺良恶性结节的鉴别诊断效能。结果CDFI检查诊断乳腺恶性结节的准确度为78.26%(72/92),特异度为77.78%(42/54),灵敏度为78.95%(30/38);UE检查诊断乳腺恶性结节的准确度为76.09%(70/92),特异度为88.89%(48/54),灵敏度为57.89%(22/38);CDFI联合UE检查诊断乳腺恶性结节的准确度为91.30%(84/92),特异度为88.89%(48/54),灵敏度为94.74%(36/38);CDFI联合UE检查诊断乳腺恶性结节的灵敏度及准确度均高于UE、CDFI单独检查。结论CDFI联合UE检查对乳腺良恶性结节具有较高的鉴别诊断效能,比单一诊断更具有优势。

基于超声导管的心输出量测量方法

提出了一种基于超声导管的心输出量测量方法,该超声导管具有两种不同中心频率的单振元换能器。使用超声导管、流量泵、体模等组成血流循环回路,实现了血流速度的检测与肺动脉图像管腔区域的分割,进而完成了心输出量测量。测量结果与蠕动泵预设流量值的平均相对误差小于2%,表明超声导管用于心输出量测量是可行的。

超声多普勒对藏族孕晚期胎儿脐带血流动力学的影响

目的探讨超声多普勒对藏族孕晚期胎儿脐带血流动力学的影响。方法选取2022年1月~2023年12月在我院行产前检查及生产的孕产妇69例。以孕周将28~31+6周设为A组、32~35+6周设为B组、36~40周设为C组,用彩色多普勒超声系统自动测量功能,采集胎儿脐动脉的搏动指数(PI)、阻力指数(RI)、脐动脉收缩期/舒张期流速比值(S/D)参数,记录并进行统计学处理。结果PI:A组1.17±0.13、B组1.04±0.14、C组0.96±0.15;RI:0.67±0.06、0.63±0.05和0.60±0.06;RI:3.10±0.52、2.87±0.51和2.53±0.40;PI、RI及S/D在不同孕周之间均有统计学差异,随着孕周增长呈下降趋势。结论高原地区(>3000米)正常妊娠胎儿脐带胎盘循环阻力随着孕周增加逐渐减低,孕晚期胎儿脐动脉PI、RI及S/D平均值较平原地区高。

超声波多普勒效应实验中异常信号来源的分析与实验研究

在超声波多普勒效应实验中发现接收器会接收到来自其超声波源的异常信号。为解释这一现象,从声波传输路径出发,假设了两种信号形成的可能路径,分别开展了物理建模分析和实验验证。最终证明实验中的异常信号源于相邻超声波源经天花板和地面的反射。进一步从理论和实验上验证了正常实验中相邻实验不会影响本地的测量结果。在面对特殊物理现象时,引导学生利用“实验现象-提出问题-提出猜想-建模分析-实验验证”的研究范式,最终解释了实验现象,训练了学生的实验思维,提高了学生解决问题的能力。

高频超声联合彩色多普勒超声检查诊断胆囊息肉样病变的价值

目的:评估高频超声联合彩色多普勒超声检查在胆囊息肉样病变(polypoid lesions of gallbladder,PLG)诊断中的应用价值。方法:选取北京电力医院在2022年4月-2023年8月收诊的108例PLG患者作为研究对象,采用高频超声(探头频率7.5-11.0MHz)与彩色多普勒超声(探头频率34.5MHz)对其进行联合检查。所有患者在入院后接受检查,并随后接受手术治疗,以手术探查和术中冰冻组织病理检查结果为金标准。结果:高频超声联合彩色多普勒超声检查在PLG良恶性鉴别诊断中表现出更高的诊断准确率、灵敏度和特异度,且对PLG不同病理组织类型的诊断符合率也优于单一检查(P<0.05);对于PLG良恶性病灶的病灶形态、病灶直径、病灶回声特点、病灶数量、胆囊壁增厚概率、病灶内有血流信号概率的比较,差异均有统计学意义(P<0.05)。结论:高频超声联合彩色多普勒超声检查是诊断PLG的有效方法,有助于早期检出PLG的良恶性,值得临床推广应用。

彩超诊断小儿肠系膜淋巴结炎的临床意义

目的:探讨彩色多普勒血流显像(color doppler flow imaging,CDFI)诊断小儿肠系膜淋巴结炎的临床价值。方法:回顾性分析2020年1月至2022年12月本院收治的86例疑似小儿肠系膜淋巴结炎的患儿临床资料,均行常规超声及CDFI检查,统计肠系膜淋巴结炎检出情况,并以临床综合诊断为金标准,分析两种超声诊断小儿肠系膜淋巴结炎的灵敏度、特异度、准确度、阳性预测值、阴性预测值;采用kappa检验验证两种超声诊断小儿肠系膜淋巴结炎与临床综合诊断的一致性;比较肠系膜淋巴结炎患儿治疗前后血流状况变化;比较本病与非本病患儿最大肠系膜淋巴结横径、纵径差异;分析超声图像表现。结果:86例疑似患儿经临床综合诊断确诊68例为肠系膜淋巴结炎,其中常规超声检出60例,阳性检出率为88.24%;CDFI检出67例,阳性检出率为98.53%;CDFI诊断小儿肠系膜淋巴结炎的灵敏度、准确度高于常规超声(P<0.05);kappa检验显示,常规超声诊断小儿肠系膜淋巴结炎与临床综合诊断的一致性尚可(kappa=0.698,P=0.000),CDFI诊断小儿肠系膜淋巴结炎与临床综合诊断的一致性极好(kappa=0.897,P=0.000);68例患儿治疗后无血流占比高于治疗前(P<0.05);肠系膜淋巴结炎患儿最大肠系膜淋巴结横径、纵径高于非肠系膜淋巴结炎患儿(P<0.05);肠系膜淋巴结炎:肠系淋巴结多分布于右下腹,形态呈椭圆形、肾形,包膜完整,呈均匀低回声,皮髓质界限模糊,且血流显像存在血流信号,以条状血流多见。正常肠系膜淋巴结:可探及淋巴结分布于右下腹、脐周居多,形态上呈长椭圆形、肾形,低回声,血流显像示内部无血流信号,也可伴星点状血流。结论:CDFI在小儿肠系膜淋巴结炎诊断中价值较高,可提高疾病诊断的灵敏度、准确度,便于开展针对性治疗。