基于［bmim］NTF2离子液体的MHD驱动

针对离子液体在化学、物理领域较少现象,提出了离子液体可作为一种新型的流体材料应用于微流控芯片。离子液体驱动方法是基于磁流体力学(MHD)原理,采用电磁场相互作用所产生的洛伦兹力,直接作用于流体以驱动流体前进的驱动方式。为了能对离子液体的驱动现象进行直观的观测和验证,设计了电磁驱动下离子液体的流速测量实验。实验结果显示,离子液体在0.4 T稳恒磁场中,8 V直流电压下流量为7.8 μL/s。对比实验与理论结果,可知电磁场驱动下离子液体的运动规律,以此可促进离子液体在微流控技术和光电子器件等领域的应用。     

Dispersive Fourier Transform Spectrometry with Variable-Thickness Variable-Temperature Liquid Cells

Dispersive Fourier transform spectrometry (DFTS) of liquids with variable-thickness variable-temperature cells is described. Different evaluative and computational methods are discussed and comparisons with the free layer method are shown with the aid of experimental results. Data for germanium and liquid chlorobenzene are presented.     

基于光纤干涉法的液体表面张力系数测量及温度影响研究

为了提高液体表面张力系数的测量精度,并充分 发挥光纤干涉法的高精度、 非接触等优点,提出了一种利用干涉原理的空心光纤(HOF)液体表面张力系数测量 方法。即利用HOF一端与单模光纤(SMF)相连,另一端与待测液面接触形成Fabry-Perot(F- P)腔 实现液体表面张力系数的测量。毛细效应使得被测液体进入HOF内,不同 的表面张力导致HOF形成的F-P腔腔长发生变化,通过检测F-P腔两个相邻干 涉峰的间距就可以间接得出液体的表面张力系数大小。实验中,分别测定了相同 温度下5种不同液体的表面张力系数和不同温度下蒸馏水的表面张力系数,对测 量的结果进行最小二乘法线性拟合。实验中,温度的改变采用水浴加热法,不同温 度下蒸馏水表面张力系数的测量结果与理论值的最大误差为0.26%。 本文方法结构 简单,容易操作,有较高的灵敏度,可为实际液体表面张力系数测量提供参考。     

新型软光电材料-离子液体电光调制特性

采用实验方法研究了新型软光电材料离子液体的电光调制特性。研究表明外加低频交流电信号时, 光功率输出与电信号相同频率振荡, 振幅受调制信号幅度和频率的共同影响, 电压幅度越大, 电压频率越低, 光输出振荡幅度越大; 外加直流电信号时, 光功率输出呈光开关状态。对影响光功率变化的因素, 如离子液体种类、调制部分物理尺寸以及离子液体折射率、电导率等进行了研究分析, 并对实验现象进行初步解释。     

Microwave Measurement of Dielectric Constant of Liquids and Solids Using Partially Loaded Slotted Waveguide (Short Papers)

An accurate method is described for the measurement of the dielectric constant of liquids and solids. The dielectric material partially loads a slotted rectangular waveguide and the guide wavelength is measured for two different thicknesses of the dielectric. The guide wavelengths are related to the dielectric constant of the material through a characteristic equation which can be solved graphically or numerically. Some experimental results are obtained and found to be in close agreement with the values of the dielectric constant available in the literature.     

液芯光纤近红外光谱特性研究

通过实验测试了液芯光纤的液芯溶液在1510～1590nm近红外波段的透光特性和不同液芯溶液的红外光谱曲线，分析了影响液芯光纤透射率的因素，为寻找可实际应用于光通信波段的液芯光纤材料提供了一些实验数据。     

Thermal self-actions of laser beams

Theoretical and experimental studies of thermal self-defocusing and self-focusing CW laser beams in liquids and solids are given. An analytical theory of thermal self-actions, including aberration phenomena, is developed. Special attention is given to the problem of thermal self-defocusing in liquids with flows (wind or convection). The new effect of continuous light-beam deflection in absorbing moving media is discussed.     

Compact substrate integrated waveguide sensor for liquids permittivity measurement

A compact substrate integrated waveguide (SIW) liquids permittivity sensor structure that utilizes half-mode (HM) and slow-wave (SW) techniques for the miniaturization of SIW sensor is presented in this paper. First, HM miniaturization technique is applied to SIW resonator cavity. Sensor width is reduced by 50% in comparison to the conventional resonator. Due to the complexity of the relationship between the complex permittivity of the substrate and liquids under test, artificial neural network tool is used as a simple and fast method to determine liquids’ complex permittivity through the measured resonant frequency and unloaded quality factor. The sensor is fabricated, and good agreement with simulations is observed according to the obtained experimental results. In the second step, SW and HM techniques are applied to the SIW sensor. The application of the HM and SW techniques indicate that an increase in sensor miniaturization while obtaining a better quality factor could be achieved. Furthermore, HM-SW-SIW is not fabricated, and we are satisfied with simulation results since we have fabricated other components. Moreover, good correspondence between the measurement and simulation results is obtained. Finally, a comparison between the structures presented in this paper and those published previously is made, demonstrating that a minimum of 25% miniaturization is achieved while maintaining acceptable characteristics.     

基于MapReduce云计算模型的自由液面模拟

Simulating turbulent liquids with breaking waves and splashes is among the most desired features in fluid animation. Lagrangian methods such as Smoothed Particle Hydrodynamics method (SPH) are a promising way to capture such properties . However, the Particlebased liquid surface simulation has not been applied very well since its consumption is way too large. This paper derives the governing equations in SPH approaches and parallelizes the dynamicsbased surface simulation with the MapReduce program models which apply the SPH approach in Cloud Computing. Compared to the serial methods , this approach obtained a 3.11 times speedup on the experimental platform.     

研究液体表面特性的激光动态光散射系统

本文介绍了我们已建立的用微机控制的激光散射实验系统,并用已知常规液体及低介面张力的二相微乳体系样品测量,实验结果与预期相符。     

折射率匹配液的稳定性及其对全息记录与再现的影响

用全息干涉计量的方法测量三维应力场分布要用到折射率匹配液,但它对系统的成像及稳定性会有影响,因此有必要对该影响进行专门研究。在理论分析的基础上设计并完成了实验研究,用加折射率匹配液前、后,以及加折射率匹配液后不同时间记录的数字全息图重构再现像,并比较这些再现像的成像位置和相位后发现:折射率匹配液会减小再现像的重构距离,但不改变全息再现像的大小,且折射率匹配液需大约15 h才能稳定。     

Method for accurate measurement of complex permittivity of tissueequivalent liquids

A microwave method for determining the electrical properties of lossy liquids is presented. The method is optimised for measuring the complex permittivity of human tissue equivalent liquids typically used together with human head phantoms in SAR (specific absorption rate) measurements. The method presented has a considerably better performance than conventional methods     

Measurement of low-absorption coefficients using the beat frequency shift between transverse modes of a laser

A new method of absorption measurement of liquids is presented. This method takes advantage of the shift in beat frequency between a strong Gaussian mode, forming a thermal lens in the liquid, and a weak first transverse mode acting as a probe to detect the thermal lens. The light absorption coefficients of the liquids are directly related to the beat frequency changes that are measured on an RF spectrum analyzer. The approach is general in that it can be used to measure the focal length of any weak lens. It appears to be more sensitive by nearly an order of magnitude than the methods that measure change in spot size.     

Modular Type III Porous Liquids Based on Porous Organic Cage Microparticles

The dispersion of particulate porous solids in size-excluded liquids has emerged as a method to create Type III porous liquids, mostly using insoluble microporous materials such as metal–organic frameworks and zeolites. Here, the first examples of Type III porous liquids based on porous organic cages (POCs) are presented. By exploiting the solution processability of the POCs, racemic and quasiracemic cage microparticles are formed by chiral recognition. Dispersion of these porous microparticles in a range of size-excluded liquids, including oils and ionic liquids, forms stable POC-based Type III porous liquids. The flexible pairing between the solid POC particles and a carrier liquid allows the formation of a range of compositions, pore sizes, and other physicochemical properties to suit different applications and operating conditions. For example, it is shown that porous liquids with relatively low viscosities or high thermal stability can be produced. A 12.5 wt% Type III porous liquid comprising racemic POC microparticles and an ionic liquid, [BPy][NTf₂], shows a CO₂ working capacity (104.30 µmol g_L⁻¹) that is significantly higher than the neat ionic liquid (37.27 µmol g_L⁻¹) between 25 and 100 °C. This liquid is colloidally stable and can be recycled at least ten times without loss of CO₂ capacity.     

Effect of Electron Drag on Performances of Carbon Nanotubes as Flow Sensors

Experimentally, the electron drag effect on carbon nanotube surface in flowing liquids was investigated. It was found that electric current could be generated in metallic carbon nanotubes immersed in the liquids. Carbon nanotubes were synthesized on Si substrate by hot filament chemical vapor deposition. The experimental results showed that the flow--induced current on the surface of carbon nanotube films was closely depended on the flow rate, concentration, properties and temperature of liquids. The flow--induced current was increased with the increasing of flow rate, concentration and temperature of liquids. The obtained results were discussed in detail.     

Multifocus Structures of Ultrashort Self-Focusing Laser Beam Observed in a Three-Photon Fluorescent Medium

Self-focusing effect and multifocus structures of an ultrashort (${sim}$160-fs) pulsed laser beam of ${sim}$ 1.3-$mu$ m wavelength are investigated in several organic liquids. The intensity-dependent self-focusing formation and multifocus structures of the infrared (IR) laser beam were directly observed in a three-photon active fluorescent dye solution cell, in which a high contrast image of the spatial structure of the self-focusing beam can be obtained due to the cubic dependence of the fluorescence intensity on the local IR laser intensity. By combining this dye solution cell with another cell filled with various transparent organic liquids, the contributions of these tested liquids to the observed self-focusing effect are elucidated. The numerical simulations for this type of self-focusing behavior are presented, based on the assumption that the major contribution to the observed self-focusing is the nonlinear refractive-index change of the solvent due to electronic-cloud distortion. The simulation results are in fairly good agreement with the experimental results.      

Calculation of the far-field halfpower width and mirror reflection coefficients of double-heterostructure lasers

A comparison is made between theoretical and experimental values of the beamwidth of a d.h. injection laser. The importance of the obliquity factor is pointed out. The good agreement between theory and experiment permits the determination of material properties from laser-diode measurements. Further, mirror reflection coefficients for lasers immersed in different liquids are calculated. Marked differences in the values of the Fresnel reflection coefficients, for normal incidence, are found.     

Quartz resonator as sensor for viscous/conductive liquids

A theoretical and experimental study of an AT-cut quartz crystal resonator as a sensor for viscous conductive liquids has been performed. A novel continuous-flow cell system and an 11 MHz quartz crystal were used for the experiments. Results are presented for aqueous dilute solutions of potassium chloride (KCl) and potassium nitrate (KNO/sub 3/).<>     

基于激光技术实现液体浓度测量的新方法

提出了一种基于激光的技术来实现流动液体浓度的实时检测。整个实验装置主要包括:耦合在单模光纤中的二极管激光器,三角形光学单元,高分辨率的半导体位移传感器。它能够在很大的范围内对二维混合液体的浓度进行实时检测,同时达到很高的分辨率。其优点是体积小,可靠性高,价格便宜。实验结果表明,测量值与真实值十分相符。