空心圆柱横截面内超声脉冲波声场的可视化研究

为了研究超声脉冲波在钢、铁、铝等空心圆柱状金属材料中的传播规律，用光学玻璃为样品，当超声脉冲波垂直于样品侧壁入射时，用研制的动态光弹系统，研究了超声脉冲纵波、横波声场的传播情况，自动记录了0-99．9μs超声波在空心圆柱横截面内经内外壁多次反射的传播图像（时间间隔0．1μs），观察了超声脉冲波在传播过程中相互耦合和频散的声场图像．由此来模拟超声波在空心圆柱金属材料中的传播行为．

固井水泥声阻抗对斜入射超声脉冲波的影响

以Isolation Scanner的工作方式为背景,采用有限差分方法模拟中心频率为250kHz的超声脉冲波自井内流体中斜入射于套管内壁界面时产生的各种模式波的声学特征与水泥环性质之间的关系。研究发现,当水泥环声阻抗不同时,接收波列的各种模式波的幅度有很大的差异,即随着水泥环声阻抗的依次降低,套管中S0模式的Lamb波逐渐增强,A0模式的Lamb波逐渐减弱;A0模式Lamb波的声衰减与水泥环声阻抗的关系是随着水泥环声阻抗的减小其声衰减系数增加。结果表明,根据A0模式Lamb波的幅度和衰减信息可以判断水泥环声阻抗的大小,为评价套管外介质的声阻抗提供了依据。通过接收波列的时域波形直接识别第Ⅱ界面是不现实的,但通过对接收波形的频谱分析有望反演水泥环的厚度。

超声脉冲波法检测混凝土缺陷试验分析

通过超声脉冲波对T梁混凝土进行检测,如某部分混凝土存在空洞,不密实或裂缝等缺陷,破坏了混凝土的整体性,通过该处的超声波与无缺陷混凝土相比较,声时明显偏长,波幅和频率明显降低,从而判断混凝土的缺陷情况。

脉冲波组织多普勒超声心动图检测肥胖患者心脏结构和心功能

目的:应用脉冲波组织多普勒超声心动图检测超重和单纯肥胖患者的心脏结构和心功能,以探讨单纯肥胖患者早期心脏功能的改变。方法:根据体重指数将143例无其他心血管疾病者分为正常体重组(体重指数18.5～23.9kg/m2,n=57),超重组(体重指数24.0～27.9kg/m2,n=53),肥胖组(体重指数≥28.0kg/m2,n=33),比较各组间左心房内径(LAD)、室间隔(IVS)厚度、左心室后壁(PW)厚度、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室重量(LVM)、左心室射血分数(LVEF)、二尖瓣舒张早期血流速度峰值(E)和二尖瓣舒张晚期血流速度峰值(A);脉冲波组织多普勒超声心动图测量二尖瓣环侧壁收缩期运动峰速度(Sm)及二尖瓣环侧壁舒张早期运动峰速度(Em),E/A,E/Em的差异,并分析这些指标与体重指数的相关性。结果:与正常体重组比较,超重组左心房内径增大、室间隔增厚,差异有统计学意义(P<0.05)。与正常体重组比较,肥胖组左心房内径、舒张末期室间隔厚度、左心室后壁厚度、左心室舒张末期内径、左心室收缩末期内径、左心室重量均增加,二尖瓣环侧壁收缩期运动峰速度、二尖瓣环侧壁舒张早期运动峰速度下降,而E/Em增加,差异均有统计学意义(P<0.05)。心脏结构和心功能变化与体重指数的相关性:左心房内径,舒张末期室间隔厚度,左心室后壁厚度,左心室舒张末期内径、左心室收缩末期内径、左心室重量与体重指数呈正相关,传统的表示左心室收缩功能和舒张功能的超声参数左心室射血分数、E/A与体重指数均无相关性,而脉冲波组织多普勒超声心动图参数二尖瓣环侧壁收缩期运动峰速度、二尖瓣环侧壁舒张早期运动峰速度与体重指数呈负相关,E/Em与体重指数呈正相关。结论:单纯肥胖可导致左心房内径、左心室壁厚度、左心室内径增加,而脉冲波组织多普勒超声心动图能够早期检测出肥胖所致的亚临床收缩及舒张功能的改变。

超声波在固体中沿圆柱形空腔散射的可视化研究

采用和金属声速接近的光学玻璃为样品．利用研制的动态光弹成像系统，研究了玻璃内圆柱形空腔对脉冲纵波和横波的散射情况，拍摄了纵波入射一对横穿圆柱形空腔的传播图像，记录了0—99．9μs时间内超声波声场散射的传播规律，利用开发的软件系统计算了超声波的爬波速度，并绘制了传播区域的声应力场图．由此来模拟超声波在非透明固体材料空腔中的传播行为，为超声波检测固体材料内部和表面缺陷提供了实验依据．

超声波检测砼缺陷的基本原理、方法和影响因素

为了进一步推广超声波检测技术的应用，笔者根据《超声法检测砼缺陷技术规程》，并结合多年的检测实践经验，阐述了超声波检测砼缺陷的基本概念、原理、测试方法和影响因素。

脉冲波组织多普勒超声心动图检测肥胖患者心脏结构和心功能

探究脉冲波组织多普勒超声心动图检测肥胖患者心脏结构和心功能的改变。方法 选取60例在我院检查者,病例收集时间为2022.3-2023.10月,按体重指数分为30例正常体重组(体重指数18.5~22.9kg/m2)为对照组,30例肥胖者(体重指数≥30.0kg/m2)为研究组,将两组患者左心房内径、舒张末期室间隔厚度、左心室后壁厚度、左心室舒张末期内径、左心室收缩末期内径、左心室重量指数、左心室射血分数、E/A、Sm、Em、E/Em进行比较。结果 与对照组比较,研究组左心房内径、舒张末期室间隔厚度、左心室后壁厚度、左心室舒张末期内径、左心室收缩末期内径、左心室重量指数、E/A、E/Em均增加,P<0.05。两组患者比较,研究组左心室射血分数、Sm、Em均降低,P<0.05。结论 脉冲波组织多普勒超声心动图在评估肥胖患者的心脏结构和功能方面具有不可替代的价值,可以通过及早发现和干预心脏问题,提高肥胖患者的生活质量和降低心血管风险,值得推广。

冲击回波法检测混凝土结构

针对目前超声脉冲波检测混凝土结构缺陷的不足,系统地阐述了冲击回波法检测结构厚度和内部缺陷、表面开口裂缝深度的原理、试验设备、实验方法和检测混凝土结构的优越性.试验分析表明冲击回波法可检测只具有一个检测面的单层混凝土结构、检测深度也有显著的提高,受结构混凝土材料组分与结构状况差异的影响也较小.

光弹法研究固体圆柱横截面上的脉冲声场

为了研究超声脉冲波在钢、铁、铝等金属棒内的传播规律,检验已有的声学理论,采用和金属声速接近的光学玻璃为样品,当超声垂直于样品侧壁入射时,利用研制的动态光弹成像系统研究了玻璃园棒内超声脉冲纵波、横波、瑞利波声场的传播特性。自动记录了0-99.9μs时间内各种超声波声场在玻璃园棒横截面上的传播图像(时间间隔0.1μs),由此来模拟超声脉冲波在金属棒横截面中的传播行为。

超声法检测混凝土质量的试验研究

采用简便有效的方法查明混凝土各种缺陷的性质、范围及大小,以便进行技术处理,是工程建设、运营养护过程中一个重要问题。目前,在诸多混凝土质量的无损检测方法中,应用最广泛、最有效的是超声法检测。

超声法检测预应力混凝土预留孔道灌浆质量的研究

后张法预应力混凝土施工中 ,灌浆是否饱满 ,将直接影响预应力构件的整体强度和耐久性。本文通过现场试验并结合工程实测 ,介绍了用超声脉冲波检测混凝土预留孔道的灌浆质量。

预应力梁锁孔混凝土的超声法检测与分析

结合长春龙家堡机场航站楼大跨度预应力梁锁孔检测的工程实例,介绍用超声脉冲波法检测预应力混凝土梁预留孔道的灌密情况.讨论提高超声波检测混凝土构件的准确度问题.并在现有检测规程的基础上将超声检测技术的方法进行了改进,为有效监测预应力混凝土梁的施工质量提供科学可靠的保障.

多普勒超声心动图测定肺动脉收缩压的研究

目的 :评估脉冲波多普勒超声心动图 (PWDE)测定肺动脉收缩压 (PASP)的准确性。方法 :4 9例心脏病患者采用 (PWDE)分别测量左右心室流出道射血前期 (PEP) ,射血期 (ET)和平均加速度 (ACCm) ,然后根据 PEP× ACCm / ET=F分别求出左右心室流出道 FL和 FR,再根据 FR/ FL =PASP/ BASP (肱动脉收缩压 )求出 PASP。并同步采用连续波多普勒超声心动图 (CWDE)测定三尖瓣返流压差 (PG- d) ,再以 PG- d加上右房压估测 PASP。结果 :采用 PWDE测定的 PASP (PASP- pd)的范围 2 7.4～ 119mm Hg (1mm Hg=0 .133k Pa) ,平均 (5 6 .2 8± 18.9) mm Hg。采用 CWDE估测的 PASP (PASP- cd)范围 2 7～ 98.5 mm Hg,平均为 (5 2 .0 2± 18.83) mm Hg,PASP- pd与 PASP- cd两者高度相关 ,相关系数为 r=0 .90 7。结论 :采用 PWDE测定 PASP准确可靠 。

双脉冲波多普勒超声评价舒张期左心室节段心肌运动及其邻近心室腔内同步血流的耦合情况

目的应用双脉冲波多普勒超声实时同步观测正常左心室壁局部心肌组织运动及相邻位点腔内多普勒血流速度频谱，评价舒张期左心室壁节段心肌应变与相邻流场压差的时空相关关系。方法应用脉冲波多普勒／组织多普勒（PW／TDI）频谱技术对86例行常规体检的健康受试者的二尖瓣处及左心室3个标准心尖长轴切面各室壁基底段、中段、心尖段的心肌舒张早期峰值速度、舒张晚期峰值速度、舒张早期血流峰值速度进行定量观察，并分析舒张期正常左心室局部心肌应变与相邻血液流场压差的时空关系。结果①左心室壁各节段舒张早期和晚期心肌运动峰值速度以及相邻腔内位点舒张早期血流峰值速度由基底、中段至心尖逐步减低（P〈0．01）。②二尖瓣环舒张早期峰值速度与二尖瓣口舒张早期血流峰值速度具有相关性（r=0．418，P〈0．001）。正常人各室壁节段心肌舒张早期峰值速度与相邻血流舒张早期峰值速度均存在相关关系，其中整体r=0．412，P〈0．001；后间隔r=0．610，P〈0．001。③左心室室壁部分节段心肌长轴应变与相邻血液流场压差间具有相关性，其中后间隔r=0．319，P〈0．005。结论左心室各节段心肌舒张早期峰值速度与相邻血流舒张早期峰值速度以及部分节段心肌长轴应变与血液流场压差间具有相关性，这种相关关系的建立有可能为临床早期精确评价左心室流固耦合提供一种全新的方法。

Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent:Pathological characteristics

AIM： To investigate the pathological characteristics of non-thermal damage induced by pulsed high intensity focused ultrasound （PHIFU） combined with ultrasound contrast agent （UCA）, SonoVue （Bracco SpA, Milan, Italy） in rabbit liver VX2 tumor. METHODS： Liver VX2 tumor models were established in 20 rabbits, which were divided randomly into PHIFU combined with ultrasound contrast agent group （PHIFU ＋ UCA group） and sham group. In the PHIFU ＋ UCA group, 0.2 mL of SonoVue was injected intravenously into the tumor, followed by ultrasound exposure of Isp 5900 W/cm^2. The rabbits were sacrificed one day after ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. The remaining tumor tissues were sent for 2,3,5-Triphenyltetrazolium chloride （TTC） staining. RESULTS： Before Trc staining, tumor tissues in both the sham and the PHIFU ＋ UCA groups resembled gray fish meat, After TIC staining, the tumor tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue, Histological examination showed signs of tumor cell injury in PHIFU ＋ UCA group, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis. Electron microscopic examination revealed tumor cell volume reduction, karyopyknosis, chromatin margination, intercellular space widening, the presence of high electro＇n-density apoptotic bodies and vacuoles in cytoplasm. CONCLUSION： The non-thermal effects of PHIFU combined with UCA can be used to ablate rabbit liver VX2 tumors.

Effects of low-intensity pulsed ultrasound stimulation on porous hydroxyapatite blocks for posterolateral fusion of lumbar spine in rabbits

he effects of porous hydroxyapatite blocks（PHABs） and an adjunct low-intensity pulsed ultrasound stimulation（LIPUS） on the fusion rate in a rabbit spinal posterolateral fusion（PLF） model were evaluated.Twenty rabbits underwent PLF with autograft and PHABs were randomly assigned to two groups：treated group with 20 min LIPUS daily and untreated control group for 4 weeks until euthanasia.The fused motion segments were subjected to manual palpation,gross observation,and radiographic investigation before histomorphologic and scanning electron microscopic analyses.Statistical differences between the LIPUS group and the control group are found in the fusion rate,bone density gray scale,trabecular bone formation,osteoblast-like cells,chondrocytes and positive expression of BMP-2 and TGF-β1 in the junction zone（significance level p〈0.05）.The results suggest that LIPUS can increase fusion rates and accelerate bone in-growth into PHAB.Hence,PHAB and LIPUS may be used together to increase fusion rates in a rabbit spinal fusion model with a promising extension to human application.

Effects of Pulse Ultrasound on Adsorption of Geniposide on Resin 1300 in a Fixed Bed

The effects of pulse ultrasound with different pulse parameters on the breakthrough curves of Geniposide on Resin 1300 were studied. The mass transfer model describing the adsorption process was constructed. Adsorption capability and the overall mass-transfer coefficient were obtained by fitting the constructed mass-transfer model and the experimental data. The effects of pulse ultrasound on adsorption of Geniposide on Resin1300 in a fixed bed were studied and compared. Amount of Geniposide adsorbed on Resin 1300 in the presence of ultrasound is lower than that in the absence of ultrasound, but the mass-transfer rate with ultrasonic irradiation is higher than that without ultrasound. Furthermore, mass transfer rate is enhanced by pulse modulation. In the conditions studied, the adsorption equilibrium constant decreases with increasing ultrasonic power, while the overall mass-transfer co-efficient increases. With increasing pulse duty ratio, adsorption equilibrium constant decreases initially, reaches a minimum when pulse duty ratio is 0.5, and then increases. On the contrary, the overall mass-transfer coefficient in-creases initially and reaches a maximum when pulse ratio is 0.5, and then decreases. Effects of pulse period on ad-sorption equilibrium and mass transfer rate reached the peak at pulse period of 28.6 ms.

Mechanism of ultrasonic-pulse electrochemical compound machining based on particles

The electric double layer with the transmission of particles was presented based on the principle of electrochemistry.In accordance with this theory,the cavitation catalysis removal mechanism of ultrasonic-pulse electrochemical compound machining(UPECM) based on particles was proposed.The removal mechanism was a particular focus and was thus validated by experiments.The principles and experiments of UPECM were introduced,and the removal model of the UPECM based on the principles of UPECM was established.Furthermore,the effects of the material removal rate for the main processing parameters,including the particles size,the ultrasonic vibration amplitude,the pulse voltage and the minimum machining gap between the tool and the workpiece,were also studied through UPECM.The results show that the particles promote ultrasonic-pulse electrochemical compound machining and thus act as the catalyzer of UPECM.The results also indicate that the processing speed,machining accuracy and surface quality can be improved under UPECM compound machining.

Performance of engineered cementitious composite containing stone slurry powder waste

Most of the materials used in engineered cementitious composite are fine in size to achieve ductile nature.Stone slurry powder(SSP)is an inert material obtained from stone industries as by-product which may cause hazardous impact on environment.In this research work,partial replacement of silica sand(SS)and fine sand(FS)by SSP with different contents(25%and 50%each)for making engineered cementitious composite has been explored.The performance was evaluated on the basis of strength,tensile strain,mid span deflection capacity,ultra-sonic pulse velocity and microstructure.Mechanical strength was found to be increased at 25%SSP in both replacements;whereas,strength decreased slightly at 50%replacement.Tensile strain,mid span deflection and quality of concrete were enhanced with increase in SSP content.Using SSP formed denser cementitious composite can help to save the natural resources and contribute in making green cementitious composite.

FPGA-based High-precision Measurement Algorithm for the Ultrasonic Echo Time of Flight

Based on the evaluation of advantages and disadvantages of high-precision digital time interval measuring algorithms, and combined with the principle of the typical time-difference ultrasonic flow measurement, the requirements for the measurement of echo time of flight put forward by the ultrasonic flow measurement are analyzed. A new high-precision time interval measurement algorithm is presented, which combines the pulse counting method with the phase delay interpolation. The pulse counting method is used to ensure a large dynamic measuring range, and a double-edge triggering counter is designed to improve the accuracy and reduce the counting quantization error. The phase delay interpolation is used to reduce the quantization error of pulse counting for further improving the time measurement resolution. Test data show that the systexn for the measurement of the ultrasonic echo time of flight based on this algorithm and implemented on an Field Programmable Gate Army（FleA） needs a relatively short time for measurement, and has a measurement error of less than 105 ps.