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将表面增强拉曼散射(SERS)光谱与磁性流体的结合应用于SERS即时(POC)检测,首先将银纳米粒子修饰到磁性Fe3O4纳米粒子表面制备磁性等离子体(AgMNPs)。AgMNPs的强磁响应性能够快速分离和检测鱼皮表面的目标分析物。制备了具有不同腔体的微流体芯片,通过磁场限制磁流体在不同腔体内的分布,从而增强了SERS信号并将检测限提高了两个数量级。磁性流体POC传感器以优异的选择性和低至皮摩尔级的高灵敏度成功检测到鱼中的孔雀石绿(MG)。实现了一种无标记、无损的光学传感方法,具有检测食品或环境中各种有害成分的潜力。 相似文献
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磁性碳纳米管吸附去除水中甲基橙的研究 总被引:1,自引:0,他引:1
采用高温催化裂解法制备碳纳米管,对其用浓硝酸氧化法进行纯化处理,并用化学共沉淀方法制备了磁性碳纳米管(简称磁性管)。利用场发射扫描电子显微镜对磁性管进行了表征。将磁分离技术应用于碳纳米管吸附性能研究,探索碳纳米管负载磁性颗粒后对甲基橙的吸附性能,寻找最佳实验条件,对吸附质溶液进行紫外-可见吸收光谱分析。同时,进行了磁性管的脱附和再吸附性能研究。 相似文献
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介绍了磁性流体拉法第旋转的形成原因,影响因素及数学模型,结果表明,磁性流本中磁性粒子磁场中成链状结构的链长度对拉法第旋转的形成起决定作用,磁场强度,磁性流体饱和磁化强度,样品池厚度,光波长及温度等都具有一定作用。 相似文献
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本文叙述了磁性荧光粉的制备方法、性能和使用方法;探讨了在制备过程中影响荧光亮度和磁力强度的一些主要因素;并研究了磁性荧光粉在水介质中使用时的分散情况.确定了制取优质磁性荧光粉的最佳条件,以及配制水磁悬液时所采用的分散剂的种类和条件.同时与日、美同类产品在技术性能上做了比较. 相似文献
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The Stockmayer fluid is often used to describe a polar fluid. The dipolar Yukawa (DY) fluid is also a useful model for such fluids and is convenient for theoretical applications. Here we use the mean spherical approximation (MSA) and perturbation theory (PT) to study the heat capacities of the DY fluid model of a polar fluid and compare these results with Monte Carlo simulations for this model polar fluid. We find that the DY fluid shows the same features as the Stockmayer fluid does; demonstrating the utility of the DY fluid and further finding that the MSA and PT approaches give reasonably accurate results for the heat capacity. 相似文献
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五维地震流体识别,即利用五维地震资料对复杂储层含流体特征进行识别和描述,为业内研究的前沿和重要难题。该文首先从岩石物理机制出发,研究了含流体各向异性储层参数与物性参数的关系,构建了高敏感参数的各向异性因子f^ani,并验证了该流体因子的合理性以及实用性。其次,利用各向异性反演算法尽可能地挖掘五维地震数据中丰富的方位各向异性信息,反演得到用来表征地下流体的各向异性因子,实了现五维地震流体识别。实际应用结果表明,基于新的各向异性因子及各向异性反演算法能够稳定可靠地从五维地震数据中获取储层流体特征,为五维地震流体识别提供了一套新的理论方法。 相似文献
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Jing-Ming Guo Chwan-Hwa Wu 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(6):1348-1358
The variable radius method is proposed to approximate the radius of the ionization channel in the one and a half-dimensional (1.5-D) fluid models for studying streamer development, in which the unreasonable constant radius in the traditional 1.5-D fluid models is corrected. The streamer development and propagation between the 1.5-D fluid model with the variable radius method and the two-dimensional (2-D) fluid model using the same initial and external conditions are compared. The radius in each stage of streamer development from the 1.5-D fluid model with the variable radius method shows agreement to a certain degree with that of the 2-D fluid model. The purpose of this paper is not to negate the role of the 2-D fluid models, but to explore the potential of the 1.5-D fluid models and make them more useful and accurate as well as to understand the evolution of streamer radius. The streamer development from the 1.5-D fluid model with the variable radius method not only maintains simplicity of the 1.5-D fluid models, but also presents agreement with the 2-D fluid models for streamers 相似文献
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Vatsala Mathur & Kavita Khandelwal 《advances in applied mathematics and mechanics.》2016,8(5):784-794
This paper presents an analysis of unsteady flow of incompressible fractional
Maxwell fluid filled in the annular region between two infinite coaxial circular
cylinders. The fluid motion is created by the inner cylinder that applies a longitudinal
time-dependent shear stress and the outer cylinder that is moving at a constant velocity.
The velocity field and shear stress are determined using the Laplace and finite
Hankel transforms. Obtained solutions are presented in terms of the generalized G and
R functions. We also obtain the solutions for ordinary Maxwell fluid and Newtonian
fluid as special cases of generalized solutions. The influence of different parameters
on the velocity field and shear stress is also presented using graphical illustration.
Finally, a comparison is drawn between motions of fractional Maxwell fluid, ordinary
Maxwell fluid and Newtonian fluid. 相似文献
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了解疏水表面的滑移规律对其在流动减阻方面的应用至关重要.利用耗散粒子动力学(dissipative particle dynamics, DPD)方法研究了微通道疏水表面的滑移现象.采用固定住的粒子并配合修正的向前反弹机制,构建了DPD固体壁面边界模型,利用该边界模型模拟了平板间的Couette流动.研究结果表明,通过调整壁面与流体间排斥作用强度,壁面能实现从无滑移到滑移的转变,壁面与流体间排斥作用越强,即疏水性越强,壁面滑移越明显,并且滑移长度与接触角之间存在近似的二次函数关系.无滑移时壁面附近密度分布均匀,有滑移时壁面附近存在低密度区域,低密度区域阻碍了动量传递,致使壁面产生滑移. 相似文献
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We study the dynamics of the noncommutative fluid in the Snyder space perturbatively at the first order in powers of the noncommutative parameter. The linearized noncommutative fluid dynamics is described by a system of coupled linear partial differential equations in which the variables are the fluid density and the fluid potentials. We show that these equations admit a set of solutions that are monochromatic plane waves for the fluid density and two of the potentials and a linear function for the third potential. The energy–momentum tensor of the plane waves is calculated. 相似文献
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ZHOU Shi-Qi 《理论物理通讯》2002,38(9)
The Ornstein Zernike equation is solved with the Rogers Young approximation for bulk hard sphere fluidand Lennard-Jones fluid for several state points. Then the resulted bulk fluid radial distribution function combinedwith the test particle method is employed to determine numerically the function relationship of bridge functional as afunction of indirect correlation function. It is found that all of the calculated points from different phase space statepoints for a same type of fluid collapse onto a same smooth curve. Then the numerically obtained curve is used tosubstitute the analytic expression of the bridge functional as a function of indirect correlation function required in themethodology [J. Chem. Phys. 112 (2000) 8079] to deterrnine the density distribution of non-uniform hard spherefluid and Lennard Jones fluid. The good agreement of theoretical predictions with the computer simulation data isobtained. The present numerical procedure incorporates the knowledge of bulk fluid radial distribution function intothe constructing of the density functional approximation and makes the original methodology more accurate and moreflexible for various interaction potential fluid. 相似文献
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This study deals with the accretion of an isotropic fluid onto a Born-Infeld black hole. For this purpose, we have formulated the fluid velocity energy density and rate of mass accretion for a singularity free black hole with the help of the barotropic equation of state and conservation laws. We have plotted the governing results to inspect the physical significance of the matter flow around the specific black hole. The spherically symmetric accretion has been analyzed for a stiff fluid, dust fluid, quintessence fluid and phantom fluid. The plotted critical quantities have been discussed by finding the critical radius, and all the plots have been shown in two regions. The fluid velocity and the energy density have positive and negative regions. It has been found that the black hole mass increases for the stiff fluid, dust fluid and quintessence fluid, but it decreases for the phantom fluid. 相似文献
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基于单相流体的概念,超临界流体的异常传热行为已经被研究很多年了,但是关于其流动传热机理仍没有统一的认识.本文通过理论分析和实验研究了超临界二氧化碳在竖直管内向上流动过程中,浮升力和流动加速效应对其流动结构和传热过程的影响.结果表明,没有确凿的实验证据表明超临界流体的异常传热行为是浮升力和流动加速直接导致的,存在的估计浮升力和流动加速效应准则均是在常物性流体的基础上,做了大量假设得出的,不同的研究者采用浮升力和流动加速准则分析超临界流体的传热恶化得出的结论不一致.最后,基于拟沸腾理论分析超临界流体的传热恶化过程,提出超临界沸腾数区分了超临界流体正常传热与恶化传热的转换边界,为超临界流体流动传热研究提供新思路,超临界沸腾数对建立用于不同技术的超临界流体动力循环的最佳运行条件具有重要意义. 相似文献