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1.
为实现微流控芯片上微液滴的检测与计数,设计了光纤式检测与计数单元,使用TracePro软件进行建模仿真以便为检测信号处理提供依据。根据液滴通过检测区域时引起的光强变化来实现计数,分析了照明光束准直性、液滴尺寸、液滴相对溶液折射率以及接收光纤相距芯片距离对光强变化的影响。仿真实验结果表明,照明光束准直性越差,液滴半径越大,相对溶液折射率越低,接收光纤距离越近,相对光强变化越明显,并且液滴大小决定着光强变化曲线中是否会出现双波谷现象,液滴半径小于13 μm时,液滴检测信号为明显的单波谷,半径大于17 μm时,液滴信号为明显双波谷。根据仿真结果提出了检测信号的处理方法,表明该单元可以实现微流控芯片上微液滴的检测与计数功能。  相似文献   

2.
制备复合液滴的微尺度流动方法   总被引:1,自引:0,他引:1       下载免费PDF全文
微尺度流动能够一步到位地制备不同结构和功能、尺寸在微米量级的复合液滴.文章回顾了几种常见的基于复合液滴的微尺度流动方法,包括同轴电雾化、复合流动聚焦、微流控芯片、玻璃微毛细管等,并对各种技术的原理和进展进行了简要概括和分析.在这类流动中,不同种类的流体在一定的几何结构通道或外力场作用下平稳地拉伸成微细射流并最终破碎成复合液滴.在同轴电雾化和复合流动聚焦技术中,从毛细管流出的流体能够形成稳定的锥-射流结构,当外力作用改变时能够形成不同的流动模式.在微流控芯片和玻璃微毛细管技术中,流体被约束在固定管道内,不同管道构型下能够形成不同的流动形态.这些方法都采用纯物理机理,过程稳定、易于操作,制备的复合液滴粒径可控,单分散性好,微观结构可设计,在科学研究和工程实际中具有重要的应用价值.   相似文献   

3.
本文基于VOF(Volume of Fluid)相界面追踪方法,建立了流动聚焦微通道中双乳液液滴形成的模型,研究了互不相溶的三种流体在微流控系统中形成双重液滴的典型物理过程,给出了双重液滴形成的典型工况,分析了流动参数和工质物性对液滴形成过程的影响。结果表明:双重乳液液滴形成过程可分为滴式与喷式两种模式;外流体流量增大时液滴形成模式由滴式转变为喷式,所形成的双重液滴尺寸减小;中间流体流量变化对液滴形成模式、所形成的双重乳液内液滴尺寸影响不明显,外液滴随中间流体流量增大而增大。  相似文献   

4.
液滴不对称分裂是获得不同尺寸微液滴的优选方法,研究液滴不对称分裂行为对于生物医学、能源化工及食品工程等领域具有重要意义.本文研制T型微通道芯片并设计搭建T型微通道液滴半阻塞不对称分裂行为可视化实验平台,研究流量调控对微液滴分裂比的影响规律,并建立理论模型对分裂比进行预测,得到以下结论:液滴不对称挤压分裂过程分为挤压前期、挤压后期和快速夹断阶段,在挤压前期,液滴颈部宽度随时间呈线性变化,在挤压后期,颈部宽度随时间呈指数关系,而在快速夹断阶段,液滴颈部向心收缩的界面附加压力占主导,液滴颈部宽度剧烈收缩,呈断崖式减小;调控分支通道流量可对液滴不对称分裂比进行调控,且调控作用受毛细数影响较大;基于液液流动压降模型的液滴分裂比预测模型能够有效预测液滴分裂比.  相似文献   

5.
采用H型放电间隙的介质阻挡放电装置,在氩气和空气的混合气体中,得到了三种新颖的等离子体发光斑图。较于传统获得的斑图,这三种发光斑图是产生在单层气隙与双层气隙结合的气隙装置之中。通过相机拍摄到的斑图照片,可以发现单层气隙和双层气隙中微放电通道呈现的发光亮度、颜色、放电面积等状态有所不同,这表明微放电通道所处的等离子体状态可能各不相同。通过分析这三种等离子体发光斑图,利用发射光谱法首次研究了单层气隙和双层气隙内微放电通道的等离子体参量。实验通过采集氮分子第二正带系(C~~3Π__u→B~~3Π__g)的发射谱线计算了单层气隙和双层气隙内微放电丝的分子振动温度,并进一步利用氩原子696.57nm(2P_2→1S_5)谱线的展宽分析了单层气隙和双层气隙内微放电丝的电子密度。结果发现:在左右相同厚度的双层气隙中,耦合微放电丝的分子振动温度基本相同,电子密度也趋于一致,单层气隙内微放电丝的分子振动温度要高于双层气隙内微放电丝,电子密度则小于双层气隙内微放电丝。单层气隙和双层气隙中不同微放电通道等离子体状态的差异性使之形成多种折射率的等离子体光子晶体,其周期性排布将具有更加丰富的带隙结构。  相似文献   

6.
针对微流控芯片通道三维形貌的可视化测量需求,搭建了一套反射式离轴双波长像面数字全息显微测量系统。首先,利用分辨率靶和标准样片对系统的横向、纵向分辨率和放大倍数进行标定实验,结果表明双波长全息显微系统在横向宽度及纵向深度测量中具有较好的准确性和可行性。然后,利用该系统分别对由PDMS材料制成的直通道、圆形小室结构微流控芯片以及硅基底微流控芯片通道进行三维形貌检测,并得到定量结果:直通道结构深度为48.6μm,宽度为75.8μm;圆形小室微通道深度为48.5μm,宽度为76.6μm;硅基底微流控芯片测量得到通道深度为61.6μm。上述结果与白光干涉仪的测量结果具有良好的一致性,说明双波长全息显微系统具有较高的可靠性和准确性,可为微流控芯片微通道检测提供新的成像检测方法。  相似文献   

7.
采用软模板法制备出了聚二甲基硅氧烷微流控装置。利用该装置讨论了正硅酸乙酯和氨水的用量分别对反应体系凝胶化时间的影响,确定了制备SiO2微球的优化反应体系,即二甲基乙酰胺、正硅酸乙酯和氨水的体积比为8∶4∶1,实验所需的反应温度为60 ℃。实验发现:在微流体通道中,分散相的流速越大,粒径越大;连续相流速越大,粒径越小。因此,通过控制微流控装置中分散相和连续相的流速制备了粒径40~220 m的单分散SiO2微球,并对其形貌进行表征。光学显微镜和粒径分析均表明所制备的SiO2微球球形度高,单分散性好。  相似文献   

8.
娄钦  臧晨强  王浩原  李凌 《计算物理》2019,36(2):153-164
将高精度的二氧化碳状态方程与气液两相流格子Boltzmann方法中的伪势模型耦合,研究微通道内二氧化碳气液两相流动的界面动力学行为,包括二氧化碳气泡和液滴的分裂、合并、变形,以及气液两相二氧化碳在演化过程中的质量交换.研究发现:当分裂和合并行为达到平衡,并且两相之间不发生质量交换时流动达到稳态.稳态时的流型主要依赖于表面张力,惯性力,管道的润湿性,以及初始体积分数.当表面张力较大时,微通道内形成的二氧化碳气泡或液滴会收缩成圆形,此时二氧化碳气泡或液滴会堵塞微通道,形成段塞流;随着表面张力的减小,形成的气泡或液滴不容易收缩,在微通道内更容易发生变形,出现泡状流或环状流.当壁面润湿性为强疏水性时,二氧化碳在微通道中的流动为环状流,其它润湿性下,流型为段塞流.体积分数较小时,二氧化碳两相流动的流型为段塞流,体积分数较大时,流型为环状流.  相似文献   

9.
受限于加工工艺,目前多数的声表面波微流控芯片,主要依靠普通的直通道调节细胞流速,从而控制微球在通道中的排列。但其形成的声场通常无法满足低能量、多功能的微流控需要。本文在普通声表面波微流控芯片的基础上,分别在频域和时域内构建声学微结构,并改变微结构阵列中铜柱间距,模拟仿真了微流控芯片输出端的电势,发现其输出端电压得到了明显的改善。当输入电信号频率在0-30MHz时,输出端电势增加约0.25V;在0-1000ns内,输出端电势增加0.015V左右;进而可以探索开发性价比更高的声波微流控芯片,针对病理检测等所存在的问题进行分析优化,提出新的细胞分离等技术。  相似文献   

10.
徐春秀  蔡龙飞 《光谱实验室》2011,28(3):1517-1519
以发射波长为473nm的二极管泵浦激光器为激发光源,搭建适于微流控液滴检测的共聚焦激光诱导荧光检测系统.系统玻璃芯片采用简易加工技术加工而成.并用2%十八烷基三氯硅烷将微通道处理为具有强疏水性质.荧光素钠溶液在T形通道交叉处被十四烷剪切形成液滴,液滴流经检测点时被激光诱导荧光系统检测.荧光素钠的检出限为1.1×10<'...  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

13.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

14.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

15.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

16.
17.
A transient suppression method for piezoelectric ceramic transducer is presented. By adding some special pedestal pulses to the original transmitted signal, the transient effects in the output of the transducer can be just precisely transmission by use of a narrowband transducer. canceled, thereby achieving the broadband The experimental results show that the transient responses of the sinusoid pulses and coded signals are suppressed successfully and the acoustic waveforms radiated into the surrounding water are improved significantly.  相似文献   

18.
We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.  相似文献   

19.
The(2 1)-dimensional nonlinear Schr(o)dinger(NLS)equation with spatially inhomogeneous nonlinearities is investigated,which describes propagation of light in(2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities.New types of optical modes and nonlinear effects in optical media are presented numerically.The results reveal that the regular split of beam can be obtained in (2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities,by adjusting the guiding parameter.Furthermore,the stability of beam regular split is discussed numerically,and the results reveal that the beam regular split is stable to the finite initial perturbations.  相似文献   

20.
In the real-world application of face recognition system, owing to the difficulties of collecting samples or storage space of systems, only one sample image per person is stored in the system, which is so-called one sample per person problem. Moreover, pose and illumination have impact on recognition performance. We propose a novel pose and illumination robust algorithm for face recognition with a single training image per person to solve the above limitations. Experimental results show that the proposed algorithm is an efficient and practical approach for face recognition.  相似文献   

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