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1.
功率超声振动系统的研究进展   总被引:3,自引:1,他引:2       下载免费PDF全文
林书玉 《应用声学》2009,28(1):10-19
功率超声振动系统是功率超声技术中的关键部分,其主要部分包括功率超声换能器、超声变幅杆以及超声工具头或超声辐射器。本文就功率超声换能振动系统设计中经常遇到的一些关键问题进行了简要的归纳和总结,目的在于为功率超声换能器的优化设计和性能改善提供一些有用的设计指南和解决措施。同时,对一些新的功率超声振动系统进行了介绍,并简要分析了其发展趋势和应用领域。  相似文献   

2.
研究了功率超声作用下,直径为10 mm Al-1%Si合金键合线水平连铸坯的微观组织形貌以及溶质元素在基体中的分布情况.实验结果表明:在功率超声作用下,铸坯的凝固组织得到了细化,Si元素在α(Al)基体中的固溶度及其分布的均匀性得到了提高,溶质偏析得到了抑制.从功率超声对Al-1%Si合金凝固过程中的溶质扩散,结晶温度间隔,液穴形态,温度场和流动场以及合金微观组织形貌的影响出发,尝试性地对功率超声抑制溶质元素微观偏析的机理进行探讨性的解释和说明. 关键词: 功率超声 水平连铸 Al-1%Si合金 溶质偏析  相似文献   

3.
功率超声在结晶过程中应用的进展   总被引:6,自引:0,他引:6       下载免费PDF全文
功率超声在结晶过程中的应用研究促进了结晶技术的发展,丰富了功率超声学和相关学科相互交叉的学术内容。以实例陈述了超声强化溶液结晶过程在化工、食品和制药行业中的应用,从熔融结晶和电结晶两方面阐述了超声改善金属结晶,综述了高分子材料和生物大分子等聚合物结晶过程中超声波的应用,总结了超声波对纳米晶型材料制备和性能的影响,着重说明了功率超声在食品冷冻中冰结晶过程的研究现状和发展方向。最后,总结了超声对结晶的强化机理。  相似文献   

4.
董胜林 《应用声学》1993,12(5):38-38
功率超声是利用超声振动形式的能量使物质的一些物理、化学和生物特性或状态发生改变,或使这种改变的过程加速的一门科学技术。与检测超声不同,功率超声是利用超声能量来对物质进行处理、加工,最常用的频率范围,是从几千赫到几十千赫,功率范围由几瓦到几万瓦。声能对物质的作用机制是功率超声较为独特的问题,也是一个比较复杂的问题,为此必须了解和究各种应用中的作用机理。  相似文献   

5.
超声波加工新技术   总被引:2,自引:0,他引:2  
超声波在国防和国民经济中的用途可分为两大类,一类是检测超声,另一类是功率超声.检测超声是利用超声波来进行各种检验和测量的技术.而功率超声则是利用超声波振动形式的能量使物质的一些物理、化学和生物性质或状态发生改变,或者使这种改变过程加快的这样一门技术,与检测超声不同,功率超声是用能量来对物质进行处理、加工.它最常用的频率是从几千赫到几十千赫,而功率由几瓦到几万瓦.由于功率超声加工技术具有许多特点,与其他加工技术相比,常能大幅度提高加工速度和效率,提高加工质量和完成一般技术所不能完成的工作.因此一在…  相似文献   

6.
郝乃澜 《应用声学》1992,11(1):47-47
超声在食品方面的应用可分为:(1)用于食品检测的小功率超声工艺;(2)用于提高食品产量和改善食品质量的大功率超声工艺。小功率超声主要用于检测诸如声速、声衰减、反射、散射等声学参量,以此获得有关食品结构或成份特征的信息。这些特征包括:液体溶解度、悬浮液中的固体含量、固体的粒度、多孔物质中的相体积比和气泡线度、乳液中的颗粒大小等等。人们已经对大量食品进行过研究,例如:腌熏的猪肉、肉类、鱼类、胶体食品、蛋类、奶制品、水果、蔬菜、果汁、葡萄酒、脂肪和油类等。近年来,许多用小功率超声获得的结果越来越引起人们的关注。  相似文献   

7.
利用超声-微波协同法提取废弃番茄叶中的叶绿素.通过单因素及正交试验研究了溶剂、乙醇浓度、微波功率、超声温度、超声时间、料液比、微波时间7个因素对叶绿素提取量的影响,再进行正交试验和验证实验.结果表明最佳工艺条件是:乙醇浓度90%、微波功率500W、超声温度70℃、超声时间40min、料液比1∶10(g/mL)、微波时间...  相似文献   

8.
这里所说的功率超声,主要是指利用较大的超声能量进行清洗、加工、处理,以及超声治疗和外科手术等,所使用的频率一般在10kHz—60kHz(有的达MHz以上),声强度从零点几瓦/cm~2到几百瓦/cm~2(一些特殊应用还要高). 我国从事功率超声的研究,已有近三十年的历史.五十年代后期,除研制出供科研用的较大型的超声设备之外,一般的功率超声设备已供应市场.目前,功率超声已渗透到国防和国民经济的许多重要领域.诸如:机械、电子、半导体、冶金、化工、能源、医药、农业、原子能以及纺织、印染和工艺美术等行业.一支功率超声的科研队伍已逐步成长起来,为国家解决了一批生产技术中的难题.特别是近几年为国家做出了显著的成绩,已有几十项成果受到省市级部门的奖励,有的还受到中央部门和国家级的奖励.设备的生产能力已达到一定的规模,每年可为市场提供约四千台设备,年产值约三千多万元.不仅通用设备已逐渐系列化,而且一些专用设备和半自动化与自动化的设备也已陆续投入市场. 国际学术交流,也陆续开展起来.近几年来已提供近十篇文章参加了国际性的学术交流,有的受到国外同行的重视和好评.我国功率超声的研究已跻身于国际行列. 下面想从功率超声的基础研究,设备的研制和生产,功率超声的应用和对国民经济建设的作用三方面,阐?  相似文献   

9.
功率超声如同超声学的其他分支学科一样,由于它在技术上具有某些独特的优点,所以近年来发展迅速,应用范围也越来越广泛。 功率超声处理技术主要包括:超声清洗,超声塑料及金属焊接,超声搪锡,超声加工;超声乳化、粉碎、分散、雾化、提取、凝聚;超声加速干燥、过滤,超声金属成形,超声处理种子,超声治疗和外科术等.本文着重介绍功率超声换能器振动系统及其在某些领域中应用的发展情况。 一、换能器、变幅杆振动系统1.功率超声换能器 超声处理用的电声换能器,按其材料分类,主要有两类:一类是压电换能器,其特点是电声转换效率高,采用夹心式结构可…  相似文献   

10.
《应用声学》2009,28(3):189-189
主办单位:中国声学学会功率超声分会协办单位:中国科学院声学研究所陕西师范大学深圳职业技术学院经中国声学学会功率超声分会研究决定,2009年11月上旬在广东省深圳市召开2009年全国功率超声学术会议。会议的主要内容是:回顾两年来国内外功率超声学科发展动态,进行学术交流,参观访问。另外,  相似文献   

11.
Power ultrasound, as an emerging green technology has received increasing attention of the petroleum industry. The physical and chemical effects of the periodic oscillation and implosion of acoustic cavitation bubbles can be employed to perform a variety of functions. Herein, the mechanisms and effects of acoustic cavitation are presented. In addition, the applications of power ultrasound in the petroleum industry are discussed in detail, including enhanced oil recovery, oil sand extraction, demulsification, viscosity reduction, oily wastewater treatment and oily sludge treatment. From the perspective of industrial background, key issue and resolution mechanism, current applications and future development of power ultrasound are discussed. In addition, the effects of acoustic parameters on treatment efficiency, such as frequency, acoustic intensity and treatment time are analyzed. Finally, the challenges and outlook for industrial application of power ultrasound are discussed.  相似文献   

12.
肖咏梅  赵贞  毛璞  王伟 《应用声学》2009,28(2):156-160
综述了超声辐照对于酶活性和酶催化反应的影响,以及各种超声参数对反应的影响,并展望了超声辐照在酶促反应中的应用前景。  相似文献   

13.
Traditionally the community of scientists involved with ultrasound has been divided broadly into those who use it as a measurement device with no effect on the medium (high frequency low power ultrasound e.g. non-destructive testing) and those who use it to produce physical or chemical effects in a medium (higher power low frequency ultrasound e.g. sonochemistry). Divisions also exist within the broad spectrum of those involved with the latter. In the early days of sonochemistry this did not prove to be a major problem, the subject was new and the field was expanding within the chemistry community. However at a point some years ago Jean-Louis Luche made the very important observation that sonochemistry applications could be subdivided into reactions which were the result of "true" and "false" effects [Synthetic Organic Chemistry by J.-L. Luche, 1998, p. 376]. Essentially these terms referred to real chemical effects induced by cavitation and those effects that could be mainly ascribed to the mechanical impact of bubble collapse. These mechanical effects have not held the interest of synthetic chemists as much as the so-called true ones but nevertheless they are certainly important in areas such as processing. In this paper I will attempt to show that there are links that can be made across many of the ultrasound "disciplines" and that these links can only serve to strengthen research in the general area of power ultrasound. If research on power ultrasound is strong then research into "pure" sonochemistry will also flourish and "false" sonochemistry will be born again as a significant research area.  相似文献   

14.
Kinetics of chitosan fragmentation by ultrasonic irradiation at frequency of 20 kHz, and the effects of experimental variables (power of ultrasound, chitosan concentration and solution temperature) on fragmentation were investigated. The kinetics studies were followed by measuring solution viscosity of the original and its fragments, and determining average number of chain scission of the fragments. The effects of ultrasonic power, chitosan concentration and solution temperature on fragmentation process were followed by viscometry and size exclusion chromatography. The chemical structure of the original chitosan and its fragments were examined by (1)H NMR spectroscopy and elemental analysis. The experimental results showed that the rate of fragmentation increased with an increase in power of ultrasound. Chain scission increased with an increase in power of ultrasound; and solution temperature, but a decrease in chitosan concentration. The chemical structure and polydispersity of the original and the fragments were nearly identical. A model based on experimental data to describe the relationship between chain scission and experimental variables (power of ultrasound; irradiation time; reduced concentration, c[eta]; and solution temperature) was proposed. It was concluded that ultrasonic irradiation is a suitable method to perform partial depolymerization and to obtain moderate macromolecules from large ones.  相似文献   

15.
In this review, the recent applications of power ultrasound technology in improving the functional properties and biological activities of biopolymers are reviewed. The basic principles of ultrasonic technology are briefly introduced, and its main effects on gelling, structural, textural, emulsifying, rheological properties, solubility, thermal stability, foaming ability and foaming stability and biological activity are illustrated with examples reviewing the latest published research papers. Many positive effects of ultrasound treatment on these functional properties of biopolymers have been confirmed. However, the effectiveness of power ultrasound in improving biopolymers properties depends on a variety of factors, including frequency, intensity, duration, system temperature, and intrinsic properties of biopolymers such as macromolecular structure. In order to obtain the desired outcomes, it is best to apply optimized ultrasound processing parameters and use the best conditions in terms of frequency, amplitude, temperature, time, pH, concentration and ionic strength related to the inherent characteristics of each biopolymer. This will help employ the full potential of ultrasound technology for generating innovative biopolymers functionalities for various applications such as food, pharmaceuticals, and other industries.  相似文献   

16.
Crystal size distribution as a function of power in ultrasound ablation is simulated by using a theoretical method based on population and radius of bubbles. In this method, population and radius of bubbles are related to ultrasound power and Debye temperature of crystals. The best power for production of crystals with uniform size is obtained from the theory. In addition, it is shown that the population of bubbles effects the radius of the productions and the radius of bubbles influences the population of products. Results from the theory are supported by experimental results.  相似文献   

17.
This work focuses on the effects of different ultrasound power densities on the microstructural changes and physicochemical properties of okara fibers, which are composed of carbohydrate-based polymers. Okara suspensions were treated with ultrasound at different power densities (0, 1, 2, 3, 4, and 5 W/mL) for 30 min, after which the ultrasound-treated okara were hydrolyzed by trypsin to obtain okara fibers. The ultrasound treatment of the okara fibers induced structural disorganization and changes, evidenced mainly in their morphological characteristics and their relative crystallinity degrees. Increasing the ultrasound power broke the okara fibers into flaky and stacked structures. When the ultrasound power density reached 4 W/mL, the parenchyma became compact and the hourglass structure fractured. The mean particle size of the okara fiber was reduced from 82.24 µm to 53.96 µm, and the homogeneity was enhanced significantly. The relative crystallinity of the okara fibers was reduced from 55.14% to 36.47%. The okara fiber surface charge decreased when the ultrasound power was increased. However, after ultrasound treatment at 4 W/mL (800 W), the okara fiber suspension exhibited the highest viscosity value and a higher swelling capacity, water-holding capacity, and oil-holding capacity. Therefore, the results indicated that the selection of processing conditions for okara fibers is critical and that okara fiber modification using a high ultrasound treatment might improve their use in potential applications.  相似文献   

18.
A review of research into the uses of low level ultrasound in cancer therapy   总被引:14,自引:0,他引:14  
The use of low power ultrasound in therapeutic medicine is a developing field and this review will concentrate on the applications of this technology in cancer therapy. The effects of low power ultrasound have been evaluated in terms of the biological changes induced in the structure and function of tissue. The main fields of study have been in sonodynamic therapy, improving chemotherapy, gene therapy and apoptosis therapy. The range of ultrasonic power levels that can be effectively employed in therapy appears to be narrow and this may have hindered past research in the applications in cancer treatment.  相似文献   

19.
The growth of silver bromide nanoparticles on polyester fiber was achieved by sequential dipping steps in alternating bath of potassium bromide and silver nitrate under ultrasound irradiation. The effects of ultrasound irradiation, concentration and sequential dipping steps in growth of the AgBr nanoparticles have been studied. Particle sizes and morphology of nanoparticle are depending on power of ultrasound irradiation, sequential dipping steps and concentration. These systems depicted a decrease in the particles size accompanying an increase in the sonication power. Results suggest that an increasing of sequential dipping steps and concentration led to an increasing of particle size. The physicochemical properties of the nanoparticles were determined by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM).  相似文献   

20.
The effects of high-intensity ultrasound on the physicochemical and gelling properties of Litopenaeus vannamei (L. vannamei) myofibrillar protein (MP) were investigated. MP solutions were subjected to ultrasound treatment (power 100 W, 300 W, and 500 W). It was found that the carbonyl and free amino contents of MP increased significantly with increasing ultrasound power, accompanied by enhanced emulsification properties. The increase of free radical and carbonyl content indicated that ultrasound induced the oxidation of MP. With the increase of ultrasound power, it was found that the total sulfhydryl content of the shrimp MP decreased, but the surface hydrophobicity increased significantly, which might be closely related to the conformational changes of MP. Meanwhile, a significant increase of β-sheet but a decrease of α-helix in the secondary structure of MP was observed with increasing ultrasound power, indicating that ultrasound treatment induced the stretching and flexibility of MP molecules. SDS-PAGE showed that L. vannamei MP consisted of myosin heavy chain, actin, myosin light chain, paramyosin and tropomyosin. Ultrasound treatment could lead to some degree of oxidative aggregation of MP. The results of rheological properties indicated that ultrasound treatment enhanced the viscoelasticity of MP and further improved the gel strength of MP gel. This study can provide a theoretical basis for the functional modification of shrimp MP and the processing of its surimi products.  相似文献   

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