氨水鼓泡吸收的实验研究——添加剂影响

为了探讨添加剂对鼓泡吸收的影响，利用滴重法测量了氨水溶液在添加剂异辛醇和正辛醇作用下的表面张力；利用可视化方法研究了氨水的鼓泡吸收特性。研究结果显示，少量添加剂可以使氨水溶液的表面张力迅速降低：当添加剂浓度一定时，在氨水浓度较低情况下，氨水的表面张力随着氨水浓度的增加而增加，但是，当氨水浓度超过10％以后，氨水溶液的表面张力反而随着氨水浓度的增加而降低；鼓泡吸收过程中，氨气流量对鼓泡频率影响较小，但是流量增大会导致最大气泡体积、最大吸收高度、以及单个气泡的舍伍德数增大；对于单个气泡而言，在一定浓度范围内，添加剂正辛醇和异辛醇可以强化鼓泡吸收。     

用超声波速度方法测试硝酸溶液浓度

用超声波分析溶液浓度的方法是基于声速与溶液相份的关系，这种关系还受到温度的较大影响，本文报道了超声速度与硝酸溶液浓度、温度关系的测量工作，实验结果显示，在质量百分比浓度为５０￣１００％范围内，声速随浓度增加而降低；在温度为１０￣５５℃范围内，声速也随温度升高而降低。根据实验结果计算了纯ＨＮＯ３液体的声速－浓度关系，本文还给出了声速法测硝酸浓度的智能仪器原理。     

超声空化效应对溶液电导率的影响

大功率超声作用于溶液时会产生空化效应,并影响溶液的物理化学性质,如电导率、液体粘度及液体表面张力等。文章对不同功率的超声作用于弱电解质溶液时其电导率的变化进行了实验研究,发现溶液电导率与超声波强度有关。当强度增大到有空化产生时,电导率开始减小;继续增大强度,溶液电导率减小到一定程度后有小幅回升现象出现。且液体内空化效应的出现将导致液体的电导率减小,空化达到一定强度时,空化效应引起的局部瞬态高温高压、冲击波和微射流导致的新导电粒子,会使电导率小幅回升。     

液体表面张力的实验研究

肥皂泡的形成与液体表面张力密切相关，而液体表面张力又与溶液的性质紧密联系。通过正交试验设计法配制不同配比溶液，利用力敏传感器法测量各自的表面张力系数大小，并测量用不同溶液吹出的肥皂泡直径大小。实验结果表明，液体表面张力最大时，存在一个最佳的浓度配比方案：而液体表面张力的大小和肥皂泡的直径大小之间并不存在线性关系。     

模拟冷却水中Al_2O_3纳米颗粒分散条件的优化

在模拟冷却水中添加Al_2O_3纳米颗粒制备纳米流体,用zeta电位表征纳米流体的稳定性。研究了十二烷基苯磺酸钠(SDBS)浓度、超声处理时间、溶液pH值对纳米流体稳定性的影响及最佳优化条件。单因素实验结果表明,随着SDBS浓度、超声处理时间、溶液pH值的增加,纳米颗粒zeta电位绝对值#ζ#均先增加后减小。在此基础上,运用响应曲面法中的BoxBehnken设计(BBD)模型对纳米颗粒分散条件进行优化,结果显示,SDBS浓度对zeta电位的贡献最大,其次为溶液p H值;SDBS浓度与pH值、超声时间与pH值两两之间的交互作用较明显;BBD模型给出模拟冷却水中纳米颗粒分散稳定性的优化条件为SDBS浓度0.339%(质量分数),超声时间61 min,pH值8.05,预测#ζ#为50.8 mV,实验测得优化条件下#ζ#为50.6 mV,与预测值接近。     

纳米溴化锂溶液稳定性及其沸腾温度研究

对既有溴化锂溶液、纳米微粒及其相应分散剂配制的纳米溶液,对比测试其与纯溴化锂溶液的表面张力和沸腾温度,探讨了该纳米溶液的热物性及稳定性。实验发现,添加纳米微粒溶液的表面张力明显降低,经过温度工艺处理后,发现溶液中纳米微粒的颗粒度降低,纳米微粒在溴化锂溶液中几乎完全溶解,纳米溶液显现出很好的稳定性,其表面张力和沸腾温度均比纯溴化锂溶液有所降低。研究表明,最佳组份配制的纳米溶液与纳米微粒和相关分散剂有关,经过严格温度处理工艺流程,可获得稳定性、热物性良好的纳米溴化锂溶液,有利于在工程中应用。     

声场强化溶液蒸发的效果及机理

声场效应对溶液蒸发过程实验表明,声场促进溶液的蒸发,不同的声场作用参数和不同的温度,影响效果不同,溶液蒸发效率提高2％-6％,平均效率提高达4％以上。对水．乙醇以及苯．乙醇二组分溶液的超声蒸发动力学过程进行了分析,表明蒸发速率随时间的关系表现出线性的关系,两组分之间的体积百分比越接近,蒸发速率随时间越容易表现出线性的变化关系。通过液气两相平衡、成核和挥发等过程的分析．认为声场强化溶液蒸发的作用机理是声场具有“空化效应”。声场降低溶液的表面张力,从而降低了成核势垒．促进了液体内部的能量交换。增加了汽化成核几率,使溶液蒸发过程得以强化。     

以酚醛树脂和沥青炭纤维为基础的炭质复合材料

权酚醛树脂和沥青炭纤维为基础的炭质复合材料，具有较高的耐热性和稳定性。该材料的性能在很大程度上取决于聚合物基质和填充剂之间的异相界面反应，首先是浸润和粘着。为保证最佳的浸润条件，创建牢固的粘着接触，研究了沥青炭纤维表面张力，酚醛树脂浸渍剂溶液浓度等对浸润性能的影响。为了缩短制品的成型时间，减少能耗，还研究了成型温度制度对炭质复合材料性质的影响。     

细胞对硅橡胶复合膜渗透蒸发分离性能的影响

利用自制的硅橡胶复合膜对乙醇-水模型溶液、含有干酵母的乙醇-水模型溶液、以及实际发酵液进行渗透蒸发分离乙醇实验,研究了细胞对膜性能的影响、结果表明：与纯乙醇模型溶液的分离相比,膜对含有干酵母的乙醇-水模型溶液、真实发酵液的分离表现出更好的性能,显示细胞的存在和活动对膜传质有一定的促进作用．连续发酵过程中,在一定的细胞浓度下（10g／L）,硅橡胶膜维持了长期稳定的分离性能;产品乙醇的有效分离降低了其对酵母细胞的抑制作用,使沉积在膜面上的细胞层促进了膜的分离性能;但提高细胞浓度（15g／L）后却因更厚的细胞层的堆积造成膜面传递状况劣化,使膜性能下降．因此发酵液中的细胞浓度、膜面上的细胞沉积以及膜性能之间存在一种最佳的相互促进和搭配关系．     

阳离子丙烯酸酯共聚物表面活性剂的结构及溶液性能

通过自由基溶液共聚合法合成了无规型阳离子丙烯酸酯共聚物表面活性剂,利用红外光谱(FT-IR)和核磁共振谱(1H-NMR和13C-NMR)对聚合产物的结构和组成进行了表征,考察了浓度、温度等对聚合物丙酮溶液的增比黏度和聚合物水溶液表面张力的影响。结果表明,聚合物丙酮溶液的增比黏度随溶液浓度增加总体呈现上升趋势,在相同溶液浓度下,其增比黏度随温度升高呈先降低后升高再降低的趋势;聚合产物可将水溶液的表面张力降低到43mN/m,其临界胶束浓度为0.8 g/L;聚合物水溶液的表面张力随温升高而降低,且随溶液pH值增大而增大。     

Decolorization of methyl orange by ozonation in combination with ultrasonic irradiation

The combination of ultrasound and ozone for the decolorization of azo dye, methyl orange, was studied. The effect of ultrasonic power, ozone gas flow rate, gaseous ozone concentration, initial dye concentration, pH and hydroxyl radical scavenger on the decolorization of methyl orange was investigated. The results showed that the synergistic effect was achieved by combining ozone with ultrasonic irradiation for the decolorization of methyl orange. The synergistic effect was more significant when the system temperature was raised due to the heat effect of ultrasonic irradiation. The decolorization of methyl orange fits the pseudo first order kinetic model. The decolorization rate increased with the increase of ultrasonic power, ozone gas flow rate, gaseous ozone concentration. However, the decolorization rate decreased with the increasing initial dye concentration. Either pH or sodium carbonate has little effect on the decolorization rate, indicating that the low frequency ultrasound enhanced ozonation process for the decolorization of methyl orange is mainly a direct reaction rather than radical reaction.     

Comparison of ultrasonic distillation to sparging of liquid mixtures

The application of intense ultrasound to a liquid-gas interface results in the formation of an ultrasonic fountain and generates both mist and vapor from the liquid. Here, the composition of the vapor and aerosol above an ultrasonic fountain is determined as a function of irradiation time and compared with the results of sparging for five different solutions. The experimental apparatus for determining the efficiency of separation consists of a glass vessel containing a piezoelectric transducer driven at either 1.65 or 2.40 MHz. Dry nitrogen is passed over the ultrasonic fountain to remove the vapor and aerosol. The composition of the liquid solutions are recorded as a function of irradiation time using gas chromatography, refractive index measurement, nuclear magnetic resonance, or spectrophotometry. Data are presented for ethanol-water and ethyl acetate-ethanol solutions, cobalt chloride in water, colloidal silica, and colloidal gold. The experiments show that ultrasonic distillation produces separations that are somewhat less complete than what is obtained using sparging.     

Action of ultrasound on the rise of a liquid in a capillary tube and its dependence on the properties of the liquid

The dependence of the ultrasonic capillary effect on the viscosity, vapor pressure, surface tension, and gas content of the liquid is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 3, pp. 513–519, September, 1980.     

超声对Ti/SnO2+Sb2O3/PbO2电极材料结构及电极性能的影响

用SEM和XRD技术测定和分析了不同超声波作用时间下Ti／SnO2 Sb2O3／PbO2电极材料的表面形貌和结构，应用循环伏安法研究了超声波作用时间对Ti／SnO2 Sb2O3／PbO2电极在1．0mol／LH2SO4溶液中的伏安特性的影响．实验结果表明：超声波作用于电极材料会对电极表面的形貌和结构产生影响；电极经超声处理20min后，其循环伏安峰电流与未经超声波作用时相比增加了近1倍；电极的电化学活性表面积随超声波作用时间的延长呈先增大后减小的趋势，在本实验中超声波作用时间为20min时，伏安电荷最大，即活性表面积最大.     

Transport and fate of volatile organic chemicals in unsaturated, nonisothermal, salty porous media: 1. Theoretical development.

A wide variety of volatile organic chemicals (VOC) have been applied to agricultural land or buried in chemical waste sites. The fate of these chemicals depends upon several mechanisms such as sorption, degradation, and transport in liquid and gaseous phases. Understanding the transport mechanisms affecting the volatile chemicals can lead to better management strategies. A theory describing inorganic solute transport, water and heat transfer, and the fate and transport of VOC in porous media has been developed. This theory includes matric water pressure head, solution osmotic pressure head, gravity pressure head, temperature, inorganic solute concentration, and VOC concentration gradients as driving forces for heat and mass transfer. The effect of surface tension, as a function of VOC concentration and temperature, on the matric water pressure head is included. The VOC can be associated with gas, liquid, and solid phases of the porous media. The gas and liquid phases are mobile, but the solid phase is immobile. The transfer of VOC across the gas/liquid, liquid/solid, and gas/solid interfaces is included using sorption-equilibrium assumptions at the interfaces. The VOC can degrade. This degradation is described by a first-order decay rate. The theory can be used to predict spatial and temporal variations of water content, temperature, inorganic concentration and the total concentration of VOC within a porous medium. The concentration of VOC in each phase can be predicted also.     

Generation of gas bubbles in microflow using micropipette with ultrasound

Ultrasound was applied to a micropipette micromixer to improve dispersion of gas and liquid in a microchannel. Flow visualization using a high-speed camera was performed to examine the effect of ultrasonic irradiation on bubble generation in the microchannel. Basically, nitrogen gas was injected using a (0.5 µm ID) glass micropipette into ethanol flowing in a rectangular (100 µm×200 µm) microchannel on polydimethylsiloxane (PDMS). Gas and liquid flow rates were regulated using mass flow controllers. At aflow condition that is typical of bubbly flow, ultrasound was transmitted into the microchannel using a piezo-electric (PZT) transducer over a range of operating voltages (2 to 200 Vp-p) and frequencies (50 to 60 kHz). Images captured during the action of the PZT transducer indicate that bubble formation is influenced by ultrasound. When subjected to ultrasound above 50 Vp-p and at the resonant frequency of the PZT transducer, bubbles formed that were smaller and closer together, signifying enhanced shearing of the gas at the micropipette tip by the liquid. The observation of gas slugs occurring sooner might be attributed to the coalescence of gas bubbles that became closely spaced.     

双频复合超声强化无水葡萄糖溶液结晶成核研究

溶液结晶技术在许多领域有着广泛的应用,其中结晶成核是溶液结晶的关键环节。以无水α-葡萄糖为研究对象,采用双频复合超声(25 k Hz+40 k Hz)强化糖液结晶成核,研究了溶液浓度、超声功率和作用时间对成核速率的影响,对单频和双频作用的晶核形态进行了对比,并采用碘化钾溶液中碘的释放量研究超声空化产额。研究结果表明:在同等条件下,双频复合超声降低了溶液成核的初始浓度,提高了成核速率,同时得到粒度均匀的晶核;双频复合超声的空化产额远高于单频25 k Hz超声和单频40 k Hz超声的空化产额,双频复合超声具有协同作用。双频复合超声强化溶液成核是一种快速、高效、节能的方法。     

微圆管内R1234ze(E)流动沸腾的环状流特性模拟研究

本文建立了制冷剂R1234ze(E)在微圆管内流动沸腾过程中的环状流模型,对传热和气液两相流动压降进行了模拟研究。综合考虑重力、表面张力及气液界面剪切力的影响,模拟分析了周向液膜不均匀分布特性及该特性对流动与换热的影响,经验证,计算结果与已有实验结果吻合较好,此外还研究了不同因素对环状流区域表面传热系数与压降的影响。模拟结果表明：在流动起始区域,截面液膜厚度的分布受重力作用影响,随着流动沸腾过程的进行,该影响作用开始减弱,且有重力作用时的环状流平均表面传热系数高于无重力作用时的环状流平均表面传热系数,随着重力加速度的增加,环状流的平均表面传热系数不断增大;随着质量流速的增大,表面传热系数与压降均随之增大;随着管径增大,表面传热系数与压降均随之减小。     

Experimental Study on Distribution Characteristics of Condensate Droplets Under Ultrasonic Vibration

This paper studied the effect of ultrasound on distribution characteristics of condensate droplets on a vertical metal surface. The surface was made of aluminum and coated with PVC film to obtain durable condensate droplets. Visualization of the condensation process was carried out under the action of ultrasonic vibration with a constant frequency of 20 kHz. The effects of ultrasonic power on surface coverage of condensate droplets, first shedding time of condensate droplets, total number of shedding, heat flux and condensation heat transfer coefficient were analyzed. Furthermore, the mechanism of ultrasonic vibration on accelerating the shedding of condensate droplets was discussed. The results indicated that the shedding of condensate droplets was accelerated by ultrasound compared with those without ultrasound. In addition, the shedding period of condensate droplets was decreased with the increase of ultrasonic power. Contrarily, the heat flux and the condensation heat transfer coefficient were increased with the increase of ultrasonic power. The maximum enhancement ratio of heat transfer coefficient reached 2.67 compared with that without applying ultrasound. This study shows that ultrasound has a good application prospect in strengthening condensation heat transfer, particularly for space applications in microgravity environment.     

点聚焦超声辐照下液体中的声场和声化学场分布

通过数值模拟和实验分别研究了点聚焦超声换能器在液体中直接辐照和间接辐照时产生的声场和声化学场分布。研究结果表明,在直接辐照时,数值模拟得到的液体中声压较大位置与声化学反应场位置相一致:在聚焦超声焦点处及液体表面附近。当使用间接辐照时,焦点处声压减小,在试管底与超声换能器之间形成驻波。为了增加间接辐照时容器内的声压,实验使用底端贴有薄膜的双通试管,通过计算机模拟和实验证明在该情况下,容器内声压,特别是容器焦点处声压和声化学反应场有所增强。