首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 93 毫秒
1.
《应用声学》1999,18(2):2
本文从理想混合液的基本假设出发,由声速公式导出了混合液的特性声阻抗表达式。在此基础上对二元混合液的特性声阻抗进行了讨论。对甘油和乙醇,进行了混合实验,由本文导出的公式所计算出的混合液的特性声阻抗值与由实验所测得的值符合较好。  相似文献   

2.
通过液体声速与表面张力系数之间的关系及理想混合液的基本假设 ,导出理想混合液表面张力系数的表达式 ,讨论了二元混合液的表面张力系数 ,给出了计算混合液表面张力系数的新方法 .  相似文献   

3.
本文考虑到绝热压缩系数与温度的关系,导出了混合液声速与温度、液体比例的关系式。测量了由两种挥发速度不同的液体组成的混合液的声速与温度、液体比例的关系。结果表明,由于挥发速度不同,给测量结果带来较大误差。本文结果除对充液聚焦球内液体选择和配制有重要意义外,也适用于其它各种混合液。  相似文献   

4.
含苯混合液拉曼光谱的特征及其应用的研究   总被引:1,自引:0,他引:1  
本文以苯和四氯化碳混合液为例,研究了含苯混合液拉曼光谱的特征,定性得出了苯与四氯化碳的质量比和其特征峰强度比的线性关系.并通过焓值计算,提出了在非极性分子混合液中定性鉴别苯的存在和含量的方法.  相似文献   

5.
韩康健  季振林 《声学学报》2023,48(2):373-382
为研究有限振幅声波作用下圆孔的非线性声学特性,提出了基于三维时域计算流体动力学(CFD)仿真的圆孔非线性声阻抗提取方法,通过求解层流方程来模拟声信号在圆孔及上下游的传播,以及采用横向周期性边界条件来考虑高穿孔率时圆孔之间相互作用的影响。研究了不同幅值声波作用下孔径、厚度和穿孔率对声阻抗的影响规律,通过对质点振速幅值、频率和板厚等组成的无量纲参量进行非线性回归分析,得到了圆孔非线性声阻抗的拟合公式,并将其转换为可考虑多频声波影响的时域模型。最后结合声阻抗时域模型和有限差分方法计算了直通穿孔管消声器在小振幅和有限振幅声波作用下的传递损失,通过与实验测量结果的比较,验证了拟合公式的准确性和实用性。  相似文献   

6.
闫向宏  张亚萍 《计算物理》2002,19(6):507-511
根据Jacobson的液体分子自由程理论和液体声速与分子自由程的关系,推导出多元有机混合液声速的温度系数,压力系数和非线性声参量B/A的计算公式,并根据组成多元有机混合液各组分特性参量(密度,自由程,非线性声参量B/A,等压膨胀系数,等温压缩系数等),利用给出的公式对声速的温度系数,压力系数,非线性声参量B/A进行了数值计算,并将计算结果与实验结果进行了比较。  相似文献   

7.
盛胜我 《应用声学》1988,7(3):12-16
抗性消声器的消声性能与管口辐射特性密切相关。本文主要研究存在气流时管口声阻抗的变化。在实验室管道系统中,测定了管口声压反射系数以及声阻抗的变化,并与理论分析的结果加以比较,提出了相应的半经验半理论公式。实验结果与理论计算符合良好。理论与实验都表明,气流对管口的反射系数与声阻抗有一定的影响。当反射系数接近1时,随气流速度的增高,管口辐射声功率将明显变化。  相似文献   

8.
本文叙述了充液聚焦球内低声速液体的声速测量,测得了声速与温度、混合比的关系曲线。用Wood混合液声速公式和测量结果导出了低声速液体的声速与温度、混合比的经验公式,解释了测量声速曲线和公式声速曲线出现的差异,本文对充液聚焦球内低声速液体的设计提供了实验基础和理论依据。  相似文献   

9.
杨同盛 《应用声学》1991,10(5):28-29
充液聚焦球内混合液的混合比是充液聚焦球的性能参数.本文给出了混合液比例变更的计算方法,最大限度地利用了原混合液,在充液聚焦球的使用上可获得经济效益.  相似文献   

10.
卢义刚  冯金垣  董彦武  仝杰 《物理学报》1999,48(11):2082-2086
依据Jacobson液体分子自由程理论及液体声速与分子自由程关系,推导出二元有机混合液的声速温度系数表达式.由此计算出的二元有机混合液的声速温度系数值与实验值符合较好. 关键词:  相似文献   

11.
本文以乙醇-甲酰胺,乙腈-甲酰胺,乙醇-环己酮,乙腈-环己酮四种混合溶液为研究对象,采用激光拉曼光谱对四种溶液体系的闪点行为进行讨论和研究。通过测定四种溶液体系的拉曼光谱和闪点,结合溶液拉曼光谱的特征峰强度比和拉曼位移的变化,探索四种溶液闪点的变化规律。试验结果表明,随着溶液浓度的增大,溶质的拉曼特征峰强线性增加,混合溶液的闪点降低。采用三次多项式分别对四种溶液体系的闪点与拉曼特征峰、溶液浓度的关系进行拟合,拟合结果良好。混合溶液的闪点随拉曼特征峰强比、溶液浓度的变化趋势相同。该试验方法将有助于从分子结构角度分析混合溶液的闪点变化规律,同时该方法可用于混合溶液闪点的实时在线检测。  相似文献   

12.
介绍了EAST 装置离子回旋加热系统中的两种实现阻抗匹配的方式, 用三支节液态调配器取代传统的 滑竿式三支节调配器和用液态相移器与单支节液态调配器相结合组成液态阻抗匹配系统。通过对液态阻抗匹配 系统的分析, 表明这两种方式都能够较好地实现阻抗匹配。  相似文献   

13.
ABSTRACT

Monte Carlo simulations in the isothermal-isobaric ensemble are used to investigate the formation of an ordered, biaxial nematic phase in a binary mixture of thermotropic liquid crystals. The orientational dependence of the interaction between molecules of each pure component is the same as in the well-known Maier-Saupe model; each pure component of the mixture is therefore capable of forming a uniaxial nematic phase. For the interaction between molecules of different components, we use the same Maier-Saupe model but change the sign of the coupling constant. As a consequence a T-shaped arrangement of these molecules is energetically favoured. The formation of the biaxial phase occurs in two steps. At higher temperatures T, one of the components forms a uniaxial nematic phase whereas the other is in a quasi two-dimensional restricted isotropic liquid state. We develop a simple theoretical model to understand the high degree of (ostensible) nematic order in the latter. At lower T, the second component becomes nematic and then the entire mixture of the two compounds has biaxial symmetry. The biaxial nematic phase does not demix into domains rich in molecules of one or the other species.  相似文献   

14.
Awasthi A  Shukla JP 《Ultrasonics》2003,41(6):477-486
Complex formation in ternary liquid mixtures of dimethylsulfoxide (DMSO) with phenol and o-cresol in carbontetrachloride has been studied by measuring ultrasonic velocity at 2 MHz, in the concentration range of 0.019-0.162 (in mole fraction of DMSO) at varying temperatures of 20, 30 and 40 degrees C. Using measured values of ultrasonic velocity, other parameters such as adiabatic compressibility, intermolecular free length, molar sound velocity, molar compressibility, specific acoustic impedance and molar volume have been evaluated. These parameters have been utilized to study the solute-solute interactions in these systems. The ultrasonic velocity shows a maxima and adiabatic compressibility a corresponding minima as a function of concentration for these mixtures. The results indicate the occurrence of complex formation between unlike molecules through intermolecular hydrogen bonding between oxygen atom of DMSO molecule and hydrogen atom of phenol and o-cresol molecules. The excess values of adiabatic compressibility and intermolecular free length have also been evaluated. The variation of both these parameters with concentration also indicates the possibility of the complex formation in these systems. Further, to investigate the presence of O-HO bond complexes and the strength of molecular association with concentrations, the infrared spectra of both the systems, DMSO-phenol and DMSO-o-cresol, have been recorded for various concentrations at room temperature (20 degrees C). The results obtained using infrared spectroscopy for both the systems also support the occurrence of complex formation through intermolecular hydrogen bonding in these ternary liquid mixtures.  相似文献   

15.
D. Lukas  N. Pan  M. Weng  E. Kostakova  P. Mikes  M. Pociute 《Physica A》2010,389(11):2164-2176
The classic theory to derive the characteristic Rayleigh wavelength, i.e., the distance between neighbouring droplets into which an originally cylindrical liquid body disintegrates, as a consequence of Rayleigh instability, is analysed in terms of the phenomenon of self-organization due to the mechanism of ‘fastest forming instability’. The paper aims at simulating this self-organization with Monte Carlo dynamics while accounting spatial interactions in lattices of Markov Random Fields that enable also modelling of Plateau-Rayleigh instability of instable mixtures of dispersed immiscible liquids. The Hammersley and Clifford theorem, concerning the general form of energy function, belonging to Markov Random Fields, is introduced for detailed classification of a simple model used for computer simulation. The relevant Auto-model, with Kawasaki dynamics, is chosen to investigate the liquid jet and the instability of the liquid’s cylindrical film. The computer-simulated outputs show encouraging agreement with the classic analytical predictions on main features of the Rayleigh instability. The model is also used as a foundation stone for developing a simple analytical approach for the estimation of Rayleigh wavelength of jets and cylindrical films, composed of instable mixtures of immiscible liquids. Qualitatively, the theory agrees with both computer simulation and experiment.  相似文献   

16.
采用三支节液态调配器使离子回旋加热(ICRH)天线系统达到阻抗匹配,在阻抗匹配的条件下结合频率调制技术来减小由天线输入阻抗变化所引起的反射功率。数值模拟了频率调制前后天线负载与反射系数的变化关系,用来验证频率调制对ICRH天线中阻抗匹配装置的影响。模拟结果表明:三支节液态调配器结合频率调制方法,能更好地降低天线传输系统的反射系数,使得发射机的功率通过天线辐射更加有效地耦合到等离子体中去。  相似文献   

17.
W-Mo系复合材料的制备及其特性波阻抗   总被引:1,自引:0,他引:1       下载免费PDF全文
 采用放电等离子烧结技术,在相同的温度(1 473 K)及压力(30 MPa)下,制备出不同配比的致密的W-Mo系复合材料样品。采用高精度超声波脉冲回波重合方法,精确测量了超声波在样品中传播的横、纵波声速,并由此得到样品的特性波阻抗值。对样品的相组成分析及电子探针分析的结果表明,W-Mo系复合材料主要是以W、Mo机械混合的形式通过粘结相获得致密化的。因此,选用混合物模型对其特性波阻抗值进行了理论预测,与实测值的比较表明该模型能对W-Mo系复合材料的特性波阻抗作出比较准确的预测。  相似文献   

18.
苯-水混合液体的乳化机理研究   总被引:6,自引:0,他引:6       下载免费PDF全文
 以研究液体混合材料的冲击压缩状态方程和高温高压条件下的相变机理为最终目标,测量了在常态下苯-水-乳化剂三元样品均匀混合的表面张力、稳定性和粒度分布等量化指标,并讨论了不同制备方法对乳状液性质的影响。实验数据表明,苯-水-乳化液属于热力学不稳定体系;表面张力介于苯和水的张力之间,但不等于二者的简单平均,这与文献值一致;苯-水-乳液的制备、存储和使用环境温度不易超过53 ℃;用超声波处理后的乳液粒度分布区域变窄,但平均粒度变化不明显。本研究为解决液体混合物、特别是难于互溶的多元液体物质爆轰实验样品初始状态的量化难题提供了可靠的数据,对类似实验的制样也具有参考价值。  相似文献   

19.
In this study, the effect of the metallization thickness in finlines on semiconcuctor substrate is researched. The propagation parameters are computed to measure the inluence of the metallization. The theory and numerical results are presented to the propagation constant and characteristic impedance of the bilateral and unilateral finlines. The full wave analysis of the transverse transmission line — TTL method is used to determine the electromagnetic fields of the structure in Fourier transform domain — FTD. Applying the suitable boundary conditions, the moment method and expanding the fields in a set of suitable bases functions, a homogeneous matrix system is obtained and the propagation constant is computed. The characteristic impedance is obtained using the relation of the voltage in the slot and the transmitted power by the structure.Computational programs are developed to obtain numerical results to the propagation parameters composed by the propagation constant and characteristic impedance.This work received financial support by CAPES and CNPq.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号