超声功率对电化学沉积铜过程速率的影响

测定了H2SO4-CuSO4溶液中，超声频率为24kHz时，超声功率对铜电化学阴极沉积过程速率的影响。实验结果表明，在超声作用下铜电化学阴极沉积过程的电流密度明显提高，即超声作用能提高过程的沉积速率。超声对铜电化学沉积过程速率强化程度随超声功率的增加而增大；在相同温度和超声功率下，超声强化速率的效果从反应控制区域（低操作过电位）向传质控制区（高操作过电位）过渡时而更加显著；在其它条件相同的情况下，超声对铜电化学沉积过程速率的强化程度随温度的升高而减小：超声强化速率的效果与溶液中铜离子的浓度基本无关。     

δ/γ transformation in non-equilibrium solidified peritectic Fe-Ni alloy

Through phase transformation kinetic analysis and experimental observation, the δ/γ transformation occurring in the non-equilibrium peritectic Fe-4.33at.%Ni alloys was systematically investigated. According to JMA solid-state transformation kinetic theory, the Time-Temperature-Transformation (TTT) curves of the δ/γ transformation in peritectic Fe-Ni alloy were calculated. On this basis, the physical correlation between the δ/γ transformation and the initial undercooling of melt (△T) was elucidated. The results indicate that the change of △T can alter not only the overall δ/γ transformation pathways but also the transformation fraction with respect to each transformation mechanism.     

恒载超声雾化制取金属粉末的改进方法

本文提出一种改进的超声雾化制取金属粉末方法。克服了因变幅杆负载变化所引起的粉末产率的周期变化，给出装置的框图及有关的参数和实验结果。     

Influence of ultrasonic combined supercritical-CO2 electrodeposition process on copper film fabrication: Electrochemical evaluation

Introducing ultrasound irradiation to the electrodeposition process can significantly improve the physical and chemical properties of deposited films. Meanwhile, the beneficial effects from supercritical-CO_2, such as high diffusivity, high permeability, low surface tension, etc., would improve the electrodeposition process with better surface quality. In the shed of the light, the present work deals with the preparation of copper (Cu) films using the integrated techniques, i.e., ultrasonic-assisted supercritical-CO₂ (US-SC-CO₂) electrodeposition approach. For comparison, Cu films were also prepared by normal supercritical-CO₂ (SC-CO₂) and conventional electrodeposition methods. To investigate the characteristics of Cu films, surface morphology analysis, roughness analysis, X-ray diffraction studies (XRD), Linear polarization, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were performed. In this work, EIS analysis was utilized for interfacial charge transfer resistance analysis with 5 mM [Fe(CN)₆]^−3/−4 redox system and corrosion analysis with 3.5 wt% NaCl solution. The observed results revealed that the film prepared with the US-SC-CO₂ method have superior properties than those produced by normal SC-CO₂ and conventional methods. Due to the combination of US-SC-CO₂, the cavitation implosion occurs rapidly that enriches the deposited film quality, such as sufficient grain size, smoother surface, enhanced corrosion resistance, and charge carrier dynamics. On the other hand, the ultrasound effect with SC-CO₂ helped to remove the weakly adhered metal ions on the electrode’s surface.     

Influence of ultrasonic vibration on micro-extrusion

Micro-forming is a miniaturization technology with great potential for high productivity. Some technical challenges, however, need to be addressed before micro-forming becomes a commercially viable manufacturing process. These challenges include severe tribological conditions, difficulty in achieving desired tolerances, and short tool-life due to inability of available die materials to withstand the forces exerted on miniature dies and punches. Some of these problems can be mitigated using ultrasonic technology.The principal objectives of this work were to investigate the possibility of applying ultrasonic vibrations in the micro-forming process, to design a set of tooling for ultrasonic micro-extrusion and to observe experimentally how ultrasonic oscillations influences the forming load and the surface finish. The test results showed a significant drop on the forming load when ultrasonic vibrations were imposed, and also a significant improvement in the surface of the micro-formed parts. Based on the preliminary test results, the study demonstrated high potential for using ultrasonic oscillations as a way to overcome the difficulties brought by the miniaturization.     

太赫兹金属器件电铸工艺中电流密度研究

微电铸工艺是太赫兹全金属光栅器件成型的关键工序。金属光栅质量取决于电铸工艺中金属离子沉积的均匀性, 而电铸槽阴极附近电流密度的分布直接影响金属离子沉积的均匀性。在阳极与阴极间添加开孔的绝缘玻璃挡板可以改善阴极电流密度分布的均匀性, 研究了挡板与阴极的距离以及挡板开孔大小对阴极电流密度分布的影响, 仿真结果表明: 添加开孔绝缘挡板有助于改善阴极处的电流密度分布; 当添加的玻璃挡板开孔大小与阴极尺寸一致时, 挡板距离阴极越近, 阴极的电流密度分布越均匀。根据仿真结果设计了相应的挡板, 电铸工艺获得了较好质量的均匀金属层, 从而验证了上述仿真分析的有效性。     

Degradation of azo dye Acid black 1 using low concentration iron of Fenton process facilitated by ultrasonic irradiation

A combination of ultrasonic and low concentration iron (<3 mgL(-1)) of Fenton process (US/Fenton) has been used to treat wastewater containing Acid black 1 (AB1). The results show that the oxidation power of low concentration iron of Fenton could be significantly enhanced by ultrasonic irradiation. The degradation of AB1 in aqueous solution by US/Fenton can receive better results compared with either Fenton oxidation or ultrasonic alone. Many operational parameters, such as ultrasonic power density, the pH value, the Fe(2+) dosage, the H(2)O(2) dosage, AB1 concentration and the temperature, affecting the degradation efficiency were investigated. Also, the effects of various inorganic anions (such as Cl(-), NO(3)(-), CO(3)(2-), etc.) on the oxidation efficiency of US/Fenton were studied. Under the given test conditions, 98.83% degradation efficiency was achieved after 30 min reaction by US/Fenton. The effect of various inorganic anions was in the following decreasing order: SO(3)(2-)>CH(3)COO(-)>Cl(-)>CO(3)(2-)>HCO(3)(-)>SO(4)(2-)>NO(3)(-). The results show that the US/Fenton can be an effective technology for the treatment of organic dyes in wastewater.     

Study on the changes of ultrasonic parameters over supercritical Ni-Co electroplating process

This work discusses the influence of changes to ultrasound (US) parameters over the nickel cobalt (Ni-Co) metal thin film properties produced by supercritical CO₂ (SC-CO₂) electroplating. Additionally, Ni-Co films were produced by conventional electroplating and silent SC-CO₂ and compared against each other.The discussion on metal thin film properties revolves around variations to the bath type ultrasonic power (15 W and 20 W) and frequency (42 k Hz and 72 kHz) during experiments. The properties provided by the three electroplating processes and analyzed include: grain sizes, film elemental content analyses, surface microstructures, film hardness, corrosion resistance, surface roughness, crystalline structure and preferential growth, etc. From the results it was clear that quality of films produced by US-SC-CO₂ was improved compared to that of films produced by silent SC-CO₂, which itself was better than those produced by conventional electroplating. However, when US power was varied we observed a decline in the mechanical properties of the produced films.The combination of ultrasonic agitation with SC-CO₂ allows for improved mechanical properties such as: lower surface roughness, finer grain size and surface morphologies, increased corrosion resistance and film hardness. The ultrasound agitation applied to SC-CO₂ electroplating enhanced the formation of alloyed metal as ultrasonic agitation increased the electrolyte flowability during electroplating process resulting in increased mass transfer while at the same time achieving a surface cleaning effect which removed metal ions with poor adhesion and other unwanted particles. Moreover, application of ultrasonic agitation avoids the use of surfactants so only changes to the physical phenomena and no changes to the chemical composition of the deposited thin films were observed, meaning less pollution to the electrolyte and higher purity of the deposited films.The US-SC-CO₂ electroplating method described in this work effectively enhanced the mechanical properties of the deposited thin films compared to those produced by both silent SC-CO₂ and conventional electroplating processes.     

Influence of subcutaneous fat in surface heating of ultrasonic diagnostic transducers

The transducers of diagnostic ultrasonic equipment generate undesired local heating at the applied part of the transducer surface. The assessment of this heating is fundamental in warranting patient safety. On the standard IEC 60601-2-37, methods have been established for the reliable measurement of heating, where three tissue models based on tissue-mimicking materials are recommended: soft tissue mimic only, bone mimic close to the surface of soft tissue, and skin mimic at the surface of soft tissue. In the present work, we compared the last-mentioned tissue model with a new one using a layer of porcine subcutaneous fat inserted between the soft tissue and skin-mimicking materials. We verify significant statistical differences between models, with the average temperature rise measured for the tests without subcutaneous fat at 6.7 °C ± 1.7 °C and for the ones with subcutaneous fat at 8.9 °C ± 1.8 °C (k = 2; p = 0.95). For each model, the procedure was performed 10 times in repeatability conditions of measurement. It has been suggested that the influence of subcutaneous fat for external transducers heating evaluation should be considered, as the presence of many millimeters of subcutaneous fat is a common condition in patients. Otherwise, the transducer surface heating and, therefore, the risk to the patient may be underestimated.     

Invar Behavior in Fe-Ni Alloys is Predominantly a Local Moment Effect Arising from the Magnetic Exchange Interactions Between High Moments

I argue that the main models that have been advanced to explain Invar behavior in Fe-Ni alloys (the original, classical, Invar system) can all be shown to be critically deficient, except one: The local moment frustration model of Rancourt and Dang ( Phys. Rev. B , 54 , 12225, 1996). The latter model explains all the measured structural, magnetic, and magnetovolume features of the Fe-Ni alloys with 0-65 apc (atomic percent) Fe, based on the assumptions that these systems are predominantly high-moment in character at the temperatures of interest and that the Fe-Fe pairs have large inter-atomic separation dependencies of their magnetic exchange parameters. The large magnetovolume Fe-Fe couplings are understood (based on ab initio electronic structure calculations) as a precursor effect of the low-moment/high-moment (LM/HM) transition that has recently been observed to occur at larger Fe concentrations, as a continuous transition occurring in the range , 65-75 apc Fe (Lagarec, Ph.D. thesis, 2001).     

General qualifications for the sign of thermal expansion coefficients at low temperatures

It is shown by arguments of plausibility that when interatomic forces include mainly central two body interactions, then the sign of the thermal expansion coefficient for isotropic solids at low temperature can be negative only for solids that lack symmetry of inversion. It is deduced that for RbBr and RbI, angular three-body forces play an important role in the nearest neighbor interactions.     

超声探头的响应特性及暂态回波模型

建立检测系统的数学模型,可以更好地理解超声检测的物理本质。分析了超声波从产生、介质中传播、缺陷耦合以及接收的全过程,将缺陷回波表示为探头响应函数与缺陷响应的时域卷积。利用空间脉冲响应和基尔霍夫近似建立了超声波与平面型缺陷的耦合模型,用大平面试块底面回波和大平面响应进行反卷积求得了探头的响应函数,并详细分析了探头在不同偏置位置时不同大小缺陷响应的特点,发现缺陷回波由直达回波和边缘回波组成,直达回波和边缘回波极性相反,且直达回波的幅值远远大于边缘回波。     

数字式超声成象的相干处理

本文介绍一种新的医学超声成象处理方法－相干处理。这种方法保留和利用了不同通道中信号的相干性，因此能增强图象分辩率，改进图象的质量。     

An apparatus for the measurement of thermal expansion of solids at low temperatures

A dilatometer, using the three terminal capacitance technique, suitable for measurement of linear thermal expansion of solids in the temperature range 1.3–300 K is described. The dialtometer is designed such that the mounting system for the specimen does not undergo any significant changes in dimensions when the specimen is heated. The apparatus, therefore, yields in principle absolute values of α, the coefficient of linear thermal expansion. The performance of the apparatus has been checked by measurements on copper in the temperature range of 77–300 K. Some preliminary results on the behaviour of α for Y₁Ba₂Cu₃O_6.9 compound in the vicinity of superconducting transition temperature,T _c are also described. The system can detect relative changes in length Δl/l ₀ of about 10⁻⁸. Attempts are being made to improve the sensitivity.     

超声测距变结构控制系统的研究

本文在超声测距系统中采用了变结构控制理论，根据所测物体的反射界面和介质性质，自动调节超声波发射换能器的功率，建立了超声测距系统的数学模型，对系统方程进行了理论分析，研究了变结构控制系统的设计方法，并结合应用实例，对钻井法凿井用超声波测井仪中超声测距系统进行了计算机仿真，并在实验室进行了实验。     

An investigation of generalized lamb waves using ultrasonic reflectivity measurements

Ultrasonic critical angle reflectivity method is used to measure the phase velocity of generalized Lamb waves in cadmium and zinc platings. In addition to the free propagating modes, leaky-wave modes are also observed. Leaky waves are considered using principles familiar from the discussion of surface waves in anisotropic media and a relatively good agreement is obtained between the theoretical computations and measured data.     

Influence of atmospheric refraction on the performance of an outdoor ultrasonic pulse compression system

Nowadays, many ultrasonic sensory systems are being developed to operate outdoors, where they are finding a variety of applications, such as local positioning, vehicle navigation or obstacle detection. To assure the reliable operation of these systems under any meteorological condition, it is necessary to achieve a thorough comprehension of the effects that the different atmospheric phenomena can have on the propagation of these acoustic waves. This paper deals with one of these phenomena, atmospheric refraction, and its influence on the performance of an ultrasonic system whose signals are detected by matched filtering.     

Study on a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa

Microcystis aeruginosa, as a typical alga, produces microcystin with strong liver toxicity, seriously endangering the liver health of human and animals. Inhibiting the bloom of the Microcystis aeruginosa in lakes becomes a significant and meaningful work. Ultrasonic cavitation is currently considered to be the most environmentally friendly and effective method for the removal of Microcystis aeruginosa. However, the commercialized ultrasonic algae removal systems require multi-Langevin transducers to achieve omnidirectional ultrasonic irradiation due to the single irradiation direction of the Langevin transducer, resulting in the complex design and high energy consumption. To achieve a low-cost, simple structure, and high-efficiency algae removal system, a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa is proposed. The proposed system is major composed of a novel omnidirectional ultrasonic transducer, which generates the omnidirectional ultrasonic irradiation by its shaking-head motion coupled by two orthogonal bending vibration modes. Modal simulation, sound field simulation, and cavitation bubble radius simulation are first carried out to optimize the geometric sizes of the proposed transducer and verify the correctness of the omnidirectional ultrasonic irradiation principle. Then the vibration characteristics of the transducer prototype are measured by vibration tests and impedance tests. Finally, the feasibility and effectiveness of the proposed omnidirectional ultrasonic removal system for Microcystis aeruginosa are evaluated through the algae removal experiments. The experimental results exhibit that the algal cells damaged by ultrasonic irradiation from the proposed system do not have the ability to self-repair. In addition, the algal removal rates reached 55.41% and 72.97% after 30 min of ultrasonic treatment when the corresponding ultrasonic densities are 0.014 W/mL and 0.021 W/mL, respectively. The proposed omnidirectional ultrasonic algae removal system significantly simplifies the configuration and reduces energy consumption, presenting the potential promise of algae removal and environmental protection.     

超声波防除积垢节能技术及设备开发

传热设备的积垢问题一直是人们急于解决的一大难题，不仅影响热能利用和生产正常运转，而且会降低产品质量，增加生产成本。通过机理研究、室内试验和工厂试验，揭示了超声波防除积垢的机理，筛选出最佳的声场参数，研制出一种新型的超声波防除积垢设备，室内试验和工厂试验结果表明，超声波技术不但可以防止新垢的产生，而且可以有效地去除已有积垢，显著地提高蒸发系统传热系数和生产能力，可停止使用化学清洗剂，从而延长传热设备使用寿命，避免污染环境，该技术有可能广泛地应用于制糖工业、化肥工业、制浆造纸工业等诸多领域。