Experimental Study on Ultrasonic Cavitation Intensity Based on Fluorescence Analysis

The Ultrasonic cavitation effect has been widely used in mechanical engineering,chemical engineering,biomedicine,and many other fields.The quantitative characterization of ultrasonic cavitation intensity has always been a difficulty.Based on this,a fluorescence analysis method has been adopted to explore ultrasonic cavitation intensity in this paper.In the experiment of fluorescence intensity measurement,terephthalic acid(TA)was used as the fluorescent probe,ultrasonic power,ultrasonic frequency,and irradiation time were independent variables,and fluorescence intensity and fluorescence peak area were used as experimental results.The collapse of cavitation bubble will cause molecular bond breakage and release·OH,and the non-fluorescent substance TA will form the strong fluorescent substance TAOH with·OH.The spectra of the treated samples were measured by a F-7000 fluorescence spectrophotometer.The results showed that the fluorescence intensity and fluorescence peak area increased rapidly after ultrasonic cavitation treatment,and then increased slowly with the increase of ultrasonic power,which gradually increased with the increase of irradiation time.They first decreased and then increased with the increase of ultrasonic frequency from 20 kHz to 40 kHz.The irradiation time was the most influential factor,and the cavitation intensity of low frequency was higher overall.The fluorescence intensity and fluorescence peak area of the samples increased by 2-20 times after ultrasonic treatment,which could increase from 69 and 5238 to 1387 and 95451,respectively.After the irradiation time exceeded 25 min,the growth rate of fluorescence intensity slowed down,which was caused by the decrease of gas content and TA concentration in the solution.The study quantitatively characterized the cavitation intensity,reflecting the advantages of fluorescence analysis,and provided a basis for the further study of ultra-sonic cavitation.

Mechanism and Kinetic Model of In-situ TiB_2/7055Al Nanocomposites Synthesized under High Intensity Ultrasonic Field

In-situ TiB2/7055Al nanocomposites are fabricated by in situ melt chemical reaction from 7055Al-K2TiF6-KBF4 system under high intensity ultrasonic field,and the mechanism and kinetic model of in-situ melt chemical reaction are investigated.X-ray diffraction （XRD） and scanning electron microscope （SEM） analyses indicate that the sizes of in-situ TiB2 nanoparticles are in the range of 80-120 nm.The results of ice-water quenched samples show that the whole process contains four stages,and the overall in-situ reaction time is 10 minutes.The in situ synthesis process is controlled mainly by chemical reaction in earlier stage （former 3 minutes）,and by the particulate diffusing in later stage.The mechanism of key reaction between Al3Ti and AlB2 under high intensity ultrasonic in the 7055Al-K2TiF6-KBF4 system is the reaction-diffusion-crack-rediffusion.Furthermore,the reactive kinetic models in 7055Al-K2TiF6-KBF4 system are established.

Influence of high intensity ultrasonic vibration on microstructure of in-situ synthesized Mg_2Si/Mg composites

Coarse and agglomerated primary Mg2Si phase in in-situ synthesized Mg2Si/Mg composite with 4%Si was treated in remelting process by means of high intensity ultrasonic vibration. The effects of ultrasonic vibration duration and temperature on size,morphology and distribution of the primary Mg2Si were studied. The evolution mechanism was discussed. The microstructures of the composites were investigated by means of optical microscopy(OM) and scanning electronic microscopy(SEM). The components were inspected with energy dispersion spectrum(EDS) and X-ray diffraction(XRD). The results indicate that ultrasonic vibration does not alter two constituents of the composites,but changes the size and distribution of aggregated primary Mg2Si particles. The size of primary Mg2Si particles decreases with the increase of vibration duration and vibrating temperature. High intensity ultrasonic has little effects on the primary Mg2Si morphology. The high intensity ultrasonic vibration is an effective means to prepare well-proportioned in-situ synthesized magnesium matrix composites.

Experimental Study on the Effect of High-intensity Focused Ultrasound (HIFU) Using Sonablate-500 in the Ablation of Canine Prostate

To investigate the safety, feasibility and effectiveness of transrectal high-intensity focused ultrasound （HIFU） in the ablation of canine prostate, 20 dogs were divided randomly into 5 groups. Sixteen canine prostates were treated with the third-generation transrectal HIFU device （Sonablate-500^TM）. Transrectal ultrasound images of the prostate and prostatic urethra were observed preoperatively and postoperatively. Serial study was performed 30 min, 30 days, 60 days and 180 days after the therapy. The rectum, periprostatic tissues, and prostate were excised en bloc and the tissues were fixed for gross and histological analysis. Our results showed that the average maximal diameter of prostatic urethra was 0.59-0.11 cm before the operation and 2.57±0.98 cm 60 days after the operation. The volume of prostate was 6.5±3.12 cm^3 before the treatment while the volume was 4.13±0.23 cm^3 60 days after the treatment and the differences were statistically significant （P〈0.05）. Histologically, there was a clear demarcation between the necrotic area of the treated tissues and the unaffected surrounding tissues. All the necrotic tissues in the targeted zone broke off and the prostatic urethra became cavitary 60 days later. The more frequent complications were urinary retention and frequency and hematuria. No rectal injury occurred during the treatment. It is concluded that the third-generation transrectal HIFU is capable of destroying prostatic tissue, substantially increasing the width of the prostatic urethra without causing injury to the adjacent tissues. The risk of postoperative complications associated with HIFU was low. HIFU may become a safe, effective and minimally invasive alternative for the treatment of prostatic diseases.

高血压血瘀证的Wave Intensity技术检测

目的探讨应用Wave Intensity技术检测临床评估高血压血瘀证的可行性。方法用ALOKA Prosoundα10彩色多普勒超声仪,对高血压65例血瘀证和62例非血瘀证患者,及50例健康者检查,获取W1(前向压缩波)、W2(前向膨胀波)、NA(低振幅负向波)、时间参数(R-W1、W1-W2)等数据。结果高血压非血瘀证组的W1值较对照组增高,而血瘀证组W2、NA值较非血瘀证和对照组增高,差异均有显著性意义(P<0.01)。结论 WI技术血流动力学参数为临床综合评估血瘀证患者的心脏、血管功能提供新方法。

Effects of ultrasonic bonding parameters on reliability of flip chip GaN-based light emitting diode

This work applied the ultrasonic bonding to package flip chip GaN-based light emitting diodes （flip chip LEDs） on Si substrates. The effects of ultrasonic bonding parameters on the reliability of flip chip GaN-based LED were investigated. In the sequent aging tests, samples were driven with a constant current of 80 mA for hundreds hours at the room temperature. It was found that the electroluminescence （EL） intensity variation had a large correlation to the ultrasonic power, and then to the bonding temperature and force. A high bonding temperature and ultrasonic power and a proper bonding force improved the EL intensity significantly. It was contributed to a strong atom inter-diffusion forming a stable joint at the bonding interface, The temperature fluctuation in the aging test was the main factor to generate a high inner stress forming delamination at the interface between the chip and Au bump. As a result, delamination had retarded the photons to emit out of the LED packaging and decay its EL intensity.

Ultrasonic characterization of modified Cr_2O_3 coatings by reflection coefficient spectroscopy

Pores,microcracks and density of plasma sprayed Cr2O3 coatings before and after high-intensity pulsed ion beam(HIPIB) irradiation were investigated using the ultrasonic reflection coefficient spectroscopy(URCS).The URCS was analyzed based on an acoustic transmission model for the multi-layered structure.The longitudinal velocity in the coatings was calculated from the experimental URCS,and the attenuation coefficient expression was deduced by comparing the experimental and numerical fitting amplitude spectral lines.The longitudinal velocity of as-sprayed Cr2O3 coating is 2 002 m/s,and increases to 2 099 and 2 148 m/s after being irradiated by HIPIB with 1 and 5 shots.Correspondingly,the factor A changes from 0.046 to 0.026 and 0.020 and n from 1.702 to 1.658 and 1.649 in the attenuation coefficient expression of α=Af n.It is observed that the surface morphology of Cr2O3 coatings changes from rough and porous to smooth and uniform with the increase of shot number,which accords with the ultrasonic analyses reasonably.The URCS seems to provide a convenient and nondestructive method to characterize surface modification of the plasma sprayed coatings.

Complications of high intensity focused ultrasound in patients with recurrent and metastatic abdominal tumors

AIM: To analyze the local and systemic complications of high intensity focused ultrasound (HIFU) for patients with recurrent and metastatic abdominal tumors.METHODS: From Aug 2001 to Aug 2004, 17 patients with recurrent and metastatic abdominal tumors were enrolled in this study. Real-time sonography was taken, and vital signs, liver and kidney function, skin burns, local reactions, and systemic effects were observed and recored before, during, and after HIFU. CT and MRI were also taken before and after HIFU.RESULTS: All 17 patients had skin burns and pain in the treatment region; the next common complication was neurapraxia of the stomach and intestines to variable degrees. The other local and systemic complications were relatively rare. Severe complications were present in two patients; one developed a superior mesenteric artery infarction resulting in necrosis of the entire small intestines, and the other one suffered from a perforation in terminal ileum due to HIFU treatment. CONCLUSION: Although HIFU is a one of noninvasive treatments for the recurrent and metastatic abdominal tumors, there are still some common and severe complications which need serious consideration.

Zinc matrix composites prepared by ultrasonic assisted casting method

By ultrasonic assisted casting method SiC_p/ZA27 composites with particle diameter of 0.520μm, and volume fraction of 2%8% were prepared. The composites microstructure, effects of particles size and volume fraction on the composites properties and the function mechanism of high intensity ultrasonic in the melt were studied. The SiC particulates are uniform macro-distribution in the matrix. The TEM results show that the interface between SiC_p/ZA27 is planar without reaction products and precipitations, and there are lots of dislocations in the matrix. With the increase of the volume fraction and the size of the SiC particulates, the tensile strength, elastic modulus and Brinell-hardness of the composites increase, while elongation ratio decreases. Because of the small clusters of the micro-sized particles, the yield strength of the small diameter SiC particles reinforced composites is lower than that of the large diameter SiC partiles reinforced ones. The results show that the SiC/ZA27 composites with SiC particulates uniformly disperse in the matrix, and good cohesion between SiC_p and ZA27 is believed to be the result of the cooperative effects of acoustic cavitation and high speed acoustic streaming in ZA27 alloy melt.

低强度超声波在污水生物脱氮中的研究进展

“双碳目标”背景下新型生物脱氮工艺更具有碳减排潜力。然而,以厌氧氨氧化工艺为代表的新型生物脱氮工艺在维持稳定运行状态方面受多种因素影响,导致脱氮效率不稳定,限制了其实际应用与推广。低强度超声波技术作为一种清洁高效的物理方法具有促进污泥活性、筛选微生物菌群的特点,与生物方法相结合可提高整体脱氮效果。论文围绕低强度超声波在强化生物脱氮性能中的作用展开讨论,介绍了超声波生物效应机理,分析了声能密度、辐照时间、超声频率等影响生物脱氮的因素,并从氮转化速率、污泥活性、微生物群落及污水生物脱氮的潜在机理方面综述了低强度超声波在污水生物脱氮中的应用,旨在为低强度超声波在脱氮实际应用中提供支撑。

超声优化水凝胶支架用于促进金纳米粒子的经皮递送

背景:金纳米粒子在多功能经皮给药系统的开发中具有重要意义,较小尺寸的金纳米粒子可通过细胞间路径向真皮层渗透,然而由于易团聚和胶体形态的限制,金纳米粒子存在着难以局限发挥效应、递送效率低的问题。目的:通过结合相变纳米液滴与生物黏附性水凝胶开发一种超声优化的水凝胶支架,用于金纳米粒子的经皮递送。方法:利用乳剂溶剂挥发法制备包载金纳米粒子的超声相变纳米液滴,并将其装载到聚多巴胺修饰的甲基丙烯酰化明胶水凝胶内制备复合水凝胶支架,对超声响应性纳米金载体进行结构与化学组分的表征,对复合水凝胶支架的微观结构、孔隙率、渗透性、流变学、体外止血及抗菌性能等进行表征。通过Live/Dead染色评价复合水凝胶支架的细胞相容性,并评估低强度脉冲超声对支架材料渗透性、孔隙率和力学性能的优化效果。结果与结论:①透射电镜和紫外-可见光光谱证明纳米金载体的成功构建,粒径及电位检测结果显示超声响应性纳米金载体具有较好的稳定性;②Live/Dead染色证明,复合水凝胶支架具有一定的生物相容性;③扫描电镜下可见复合水凝胶支架具有多孔网状结构,且部分大孔内部可见纳泡受超声辐照后产生的直径约2μm的微孔,结合渗透性实验说明强度脉冲超声可以优化水凝胶支架的孔隙和渗透性;复合水凝胶支架的止血性能优于止血海绵、聚多巴胺@甲基丙烯酰化明胶水凝胶支架;在低强度脉冲超声辐照下,复合水凝胶支架具有良好的抗氧化效应与抗菌性能;④热成像结果显示金纳米粒子包载在超声响应的纳泡中,在受到超声激励下可以得到更均匀的播散;⑤力学性能测试结果表明,负载含金纳米粒子的相变纳米液滴后水凝胶支架的储能模量增加,表现出更强的力学性能,断裂伸长率为122%,延展性优于不含金纳米粒子的相变纳米液滴组(P<0.05);⑥结果表明,复合水凝胶支架具备良好的生物相容性、抗菌性、抗氧化性及止血作用。

基于超声时频分析与残差网络的生物组织变性识别

为了能对高强度聚焦超声(HIFU)治疗过程中的生物组织进行实时准确的变性识别,提出了一种基于超声时频分析与残差网络(ResNet)的生物组织变性识别方法。首先,采用广义S变换(GST)方法对生物组织超声回波信号进行时频分析,得到二维时频图;然后,通过迁移学习,将在ImageNet数据集上训练得到的参数应用于超声回波信号数据集;最后,利用ResNet101模型从生物组织变性前后的时频图中学习和提取有效的变性信息,并可视化变性特征轨迹,实时地完成生物组织变性识别。实验结果表明:相较于现有基于信号能量,AR系数以及熵特征的变性识别方法,GST-ResNet方法无需人为经验选取特征参数,具有更高的识别率,可以实时准确地完成生物组织的变性识别。

面向开环扫描系统的超声图像畸变校正方法

超声显微成像技术广泛应用于工业无损检测领域。相较于闭环、半闭环扫描系统硬件复杂、成本高,开环扫描系统结构简单、成本低,但由于无反馈机制会导致步进电机的非线性运动引起图像像素错位畸变。因此,消除非线性运动带来的错位畸变是采用开环扫描系统实现高质量超声成像的关键。该文提出集最大值投影法、最大类间方差法和中心坐标校正法于一体的MIP-Otsu-C3M方法,对开环扫描系统获得的硬币回波数据采用最大值投影法获取初始灰度图像,采用最大类间方差法获取感兴趣区域的B扫描图像边缘像素位置,并采用中心坐标校正法成功消除像素错位,解决了超声C扫描图像畸变问题。对消除错位畸变的回波数据进行飞行时间法和傅里叶变换法图像重建,直接获得了非畸变的三维图像和透视图像。该新颖算法也验证了最大值投影法可拓展至图像畸变校正应用。

双频点骨伤愈合超声波治疗仪的研究与设计

针对骨折、骨裂和骨挫伤等骨伤治疗中存在的恢复周期长、手术创伤和术后恢复期不便等问题,研制一款基于STM32单片机的骨伤愈合超声波治疗仪。该治疗仪以低强度脉冲超声波为治疗手段,通过刺激骨组织和神经系统的生物学反应,促进骨伤部位的修复和再生,并且具有非侵入性、无副作用等优点。通过实物测试证明,该治疗仪输出功率稳定,总体性能优良。目前该治疗仪已与某医院联合进行临床试验,为低强度脉冲超声波的应用开发提供一定参考。

Determination of stress intensity factors in ultrasonic fatigue loading

The application of displacement and energy approaches to the determination of stress intensity factors in ultrasonic fatigue crack growth (fcg) studies is discussed.The particular advantages as well as the limitations of the two approaches are evaluated.Two types of ultrasonic fatigue loading with different stress ratios are exerted on the specimen respectively: the ultrasonic fatigue loading with a stress ratio R=-1 and the ultrasonic fatigue excitations superposed upon a static mean stress with R】-1 From comparison the conclusion is formed that the energy approach developed in the investigation is more accurate,concise and suitable than commonly adopted approaches and/or formulas proposed.Experimental fcg data on a titanium alloy Ti-6Al-4V and the characteristic mechanism of the ultrasonic fcg are investigated.

超声与高分辨磁共振成像检查评价颈动脉斑块易损性的对比研究

目的探讨在高分辨磁共振成像(MRI)评估的基础上采用超声评估颈动脉斑块易损性的价值。方法收集2023年3月至2023年5月于茂名市人民医院同时进行超声、高分辨MRI检查的16例颈动脉斑块患者的临床资料,共检出27个颈动脉易损性斑块(含极低回声或低回声斑块,厚度≥3.5 mm)。基于高分辨动态对比增强MRI序列(DCEMRI)和超声造影,分析斑块内新生血管(IPN)的检出率。在采用高分辨MRI对颈动脉易损性斑块进行分析的基础上,通过解剖定位匹配,观察易损性成分在超声的主要表现,并测量极低回声区的超声灰阶强度(即超声回声强度),通过超声灰阶值分析超声对于区分易损性斑块成分[斑块内出血(IPH)和脂质坏死核心]的潜在价值。结果在27个颈动脉易损性斑块中,超声造影显示24个斑块内部出现超声造影剂微气泡灌注,DCE-MRI显示24个斑块出现强化。DCEMRI和超声造影对颈动脉IPN的诊断符合率为78%(21/27)。通过对18个易损性斑块极低回声区代表的成分进行分析发现18个斑块均在解剖定位上匹配成功,其中,高分辨MRI诊断7个斑块内的极低回声区为IPH,为亚急性出血,T1加权成像(T1WI)和时间飞跃(TOF)序列对亚急性出血敏感,表现为稍高或高信号;11个斑块内的极低回声区是脂质坏死核心。IPH的超声回声强度明显低于脂质坏死核心的超声回声强度,差异有统计学意义(P﹤0.05)。结论超声检查具有潜在区分易损性斑块成分的价值,有助于对颈动脉易损性斑块的早期诊断与干预,从而减少其对患者健康带来的危害。

米索前列醇对高强度聚焦超声治疗子宫肌瘤的影响

目的 探究治疗前1小时经阴道给予患者米索前列醇400μg,对高强度聚焦超声(high intensity focused ultrasound,HIFU)治疗子宫肌瘤的超声时间及治疗效果的影响。方法 回顾性分析2020年7月至2022年1月在嘉兴市妇幼保健院诊断为子宫肌瘤并接受HIFU治疗的患者123例,按照治疗方法分为常规HIFU治疗组(对照组,n=66)和米索前列醇联合HIFU治疗组(米索前列醇组,n=57),比较两组的超声时间,治疗中、治疗后不良并发症,治疗后6个月子宫肌瘤体积及临床症状随访。结果 米索前列醇组术中出现治疗区疼痛率显著高于对照组,差异有统计学意义(P<0.05)。米索前列醇组中,超声时间显著短于对照组,差异有统计学意义(P<0.05)。两组治疗后子宫肌瘤体积、子宫肌瘤体积缩小率及临床症状情况比较,差异无统计学意义(P>0.05)。结论 在HIFU治疗前1小时对患者经阴道给予400μg米索前列醇治疗子宫肌瘤,可显著缩短超声时间,对提高治疗效率有着积极作用,但并未显著减小治疗后6月的子宫肌瘤体积及减轻患者相关临床症状。

声光衍射法测量液体中超声声强的数据处理方法

为将半导体激光器用于构建声光效应及声速声强测量教学实验装置,推导了超声光栅远场衍射光场分布,给出了超声光栅相位调制系数分别与声强和各级衍射光强度的关系,总结了从衍射光场图像提取声强值的数据处理方法.通过建立交替使用氦氖激光器或半导体激光器的实验系统,进行了液体中超声声强测量的比较实验,验证了半导体激光器作为光源实现声光衍射法超声声强测量的可行性.

超声波污泥过程减量研究现状及其与新型生物脱氮工艺联用措施探讨

剩余污泥产量的逐年攀升已成为困扰我国污水处理行业发展的严峻问题,超声波技术(即高强度超声波)因具有从源头减少污泥产量的优点而倍受研究者重视。介绍了超声波污泥过程减量技术的原理及主要影响因素,综述了为提高污泥过程减量率和降低能耗的超声波改进技术研究现状,包括超声波与物化方法、与传统污水生物处理工艺的联用法。针对超声波与传统污水生物处理工艺联用存在污泥减量和出水水质恶化的矛盾,结合低强度超声波能够提高污泥生物活性并促进短程硝化过程的优点,总结出一种不同强度超声波耦合新型污水生物处理工艺(短程硝化-反硝化,短程硝化/短程反硝化-厌氧氨氧)的方法并对其技术优势进行探讨。

超声差分衰减截距成像监测高强度聚焦超声致热损伤

目的 观察以超声差分衰减截距成像监测高强度聚焦超声(HIFU)所致热损伤的可行性。方法 基于原始超声成像数据和声衰减截距数学模型开发超声差分衰减截距算法;分别以80、131、165和205 W声功率对离体猪里脊组织进行HIFU辐照,观察B型超声声像图、超声差分衰减截距图所见及猪里脊组织损伤,计算不同声功率HIFU辐照前、后热损伤区域即焦域的平均超声差分衰减截距(Δα_(0))、B型超声声像图和超声差分衰减截距图的对比度噪声比(CNR),绘制CNR动态变化曲线。结果 以80 W声功率辐照后,B型超声声像图中未见区别于背景的亮区,超声差分衰减截距图中焦域出现微弱亮区,猪里脊组织未见损伤区域;以131 W声功率辐照后,B型超声声像图中未见区别于背景的亮区,超声差分衰减截距图中见较小亮黄色区域,猪里脊组织见白色热损伤区;以165 W声功率辐照后,B型超声声像图中未见区别于背景的亮区,超声差分衰减截距图中出现亮点并于治疗结束时形成区别于背景的高亮区,猪里脊组织可见白色热损伤区;以205 W声功率辐照过程中,B型超声声像图中似见模糊微弱亮区但肉眼较难辨别,超声差分衰减截距图中可见明显高亮区且随消融时间延长而逐渐增大,猪里脊组织见白色热损伤区。至辐照结束时,131、165、205 W声功率超声差分衰减截距图的Δα_(0)平均值分别由0.04、0.07、0.10 dB/cm增至0.31、0.42、0.75 dB/cm。CNR动态变化曲线显示,131、165、205 W声功率超声差分衰减截距图的CNR曲线始终处于B型超声声像图的CNR曲线之上。结论 以超声差分衰减截距成像监测HIFU所致离体猪里脊组织热损伤可行,且监测效果优于B型超声。