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51.
Traditional cell/particle isolation methods are time-consuming and expensive and can lead to morphology disruptions due to high induced shear stress. To address these problems, novel lab-on-a-chip-based purification methods have been employed. Among various methods introduced for the separation and purification of cells and synthetics particles, acoustofluidics has been one of the most effective methods. Unlike traditional separation techniques carried out in clinical laboratories based on chemical properties, the acoustofluidic process relies on the physical properties of the sample. Using acoustofluidics, manipulating cells and particles can be achieved in a label-free, contact-free, and highly biocompatible manner. To optimize the functionality of the platform, the numerical study should be taken into account before conducting experimental tests to save time and reduce fabrication expenses. Most current numerical studies have only considered one-dimensional harmonic standing waves to simulate the acoustic pressure distribution. However, one-dimensional simulations cannot calculate the actual acoustic pressure distribution inside the microchannel due to its limitation in considering longitudinal waves. To address this limitation, a two-dimensional numerical simulation was conducted in this study. Our numerical simulation investigates the effects of the platform geometrical and operational conditions on the separation efficiency. Next, the optimal values are tested in an experimental setting to validate these optimal parameters and conditions. This work provides a guideline for future acoustofluidic chip designs with a high degree of reproducibility and efficiency. 相似文献
52.
The acoustic radiation force resulting from acoustic waves have been extensively studied for the contact-free generation of organized patterning arrays. The precise arrangement of microscopic objects clustered at the pressure nodes is critical to the development of functional structures and patterned surfaces. However, the size of the clusters is restricted by the saturation limit of the acoustic nodes. Here, we present a bulk acoustic wave (BAW) platform, which employs a two-dimensional acoustic wave to propel particles of various sizes. Experimentally, when particles are large, significant acoustic energy is scattered and partly absorbed by the matched layers in front of the sensors. The acoustic radiation force from a convergent acoustic pressure field agglomerates the large polystyrene (PS) particles towards the central region instead of the pressure nodes. The parametric analysis has been performed to assess the transition in the particles from clustering at the organized nodal arrays to agglomerating in the central region, which is a function of particle size, particle concentration, and load voltage. Statistically, the particles can agglomerate with a cluster ratio greater than 70%, and this ratio can be improved by increasing the load power/voltage supplied to the transducers. With its ability to perform biocompatible, label-free, and contact-free self-assembly, this concept offers a new possibility in the fabrication of colloidal layers, the recreation of tissue microstructure, the development of organoid spheroid cultures, the migration of microorganisms, and the assembly of bioprinting materials. 相似文献
53.
Microfluidic technology has great advantages in the precise manipulation of micro and nano particles, and the separation of micro and nano particles based on ultrasonic standing waves has attracted much attention for its high efficiency and simplicity of structure. This paper proposes a device that uses three modes of ultrasonic standing waves to continuously separate particles with positive acoustic contrast factor in microfluidics. Three modes of acoustic standing waves are used simultaneously in different parts of the microchannel. According to the different acoustic radiation force received by the particles, the particles are finally separated to the pressure node lines on both sides and the center of the microchannel. In this separation method, initial hydrodynamic focusing and satisfying various equilibrium constraints during the separation process are the key. Through numerical simulation, the resonance frequency of the interdigital transducer, the distribution of sound pressure in the liquid, and the relationship between the interdigital electrode voltage and the output sound pressure are obtained. Finally, the entire separation process in the microchannel was simulated, and the separation of the two particles was successfully achieved. This work has laid a certain theoretical foundation for the rapid diagnosis of diseases in practical applications. 相似文献
54.
艾明 《中国无机分析化学》2013,3(1):74-76
研究了采用氢化物发生-原子吸收光谱法测定食品中痕量汞的方法,通过采用氢化物发生器,选择合适浓度的载流和硼氢化钾,获得了较为满意的分析结果。在测定汞含量5~20μg/kg的食品标准样品时,测试结果相对标准偏差RSD为2.2%~3.7%,回收率为84.9%~97.5%,检出限为0.2μg/L,完全满足食品行业汞元素痕量检测要求,操作简便、快速。 相似文献
55.
Since the quality factor of an acoustic wave resonator (AWR) reached 1011, AWRs have been regarded as a good carrier of quantum information. In this paper, a scheme to construct a NOON state with two AWRs assisted by a nitrogen‐vacancy‐center ensemble (NVE) is proposed. The two AWRs cross each other vertically, and the NVE is located at the center of the crossing. By considering the decoherence of the system and using resonant interactions between the AWRs and the NVE, and the single‐qubit operation of the NVE, a NOON state can be achieved with a fidelity higher than 98.8% when the number of phonons in the AWR is . 相似文献
56.
57.
Abstract Algorithms are developed for constructing random variable generators for families of densities. The generators depend on the concavity structure of a transformation of the density. The resulting algorithms are rejection algorithms and the methods of this article are concerned with constructing good rejection algorithms for general densities. 相似文献
58.
We study a problem in stochastic functional differential equations which, in addition to a standard one-one-parameter noise term involves a random perturbation of the memory. This problem can also be regarded as a first order hyperbolic system of stochastic partial differential equations with given initial data and nonlocal boundary data. Existence and uniqueness of a solution is established and the generator of the associated Markov process is analyzed. Thereafter, for two model problems arising from first- and second-order integro-differential equations suggested by physical applications we establish asymptotic stability in probability of the associated stochastic processes. 相似文献
59.
60.
Shixiong Chen Xiaotian Zhao Ming Jin Wanqiu Huang Guodong Ye Haiyan Pan Decheng Wan 《Journal of polymer science. Part A, Polymer chemistry》2021,59(17):1899-1911
Four 1,5-diphenyl-3-aromatic heterocyclyl-2-pyrazoline-based sulfonium salt photoacid generators (PAGs) with different aromatic heterocycles substituted on C3 atom and dimethyl sulfonium group on C5 atom were synthesized. These PAGs were highly photosensitive in the 365–425 nm light-emitting diode region, and the intramolecular charge transfer from the pyrazoline ring to sulfonium salts induced efficient photolysis and high ΦH+. The heterocycles as well as their substituted positions significantly influenced the energy of the S2 orbital, which was determined by the electrochemical and absorption properties of the PAGs. The raising of the S2 orbital energy enlarged the energy gap of S0–S2 and S1–S2, resulting in blue shift of the absorption spectra and increase in the quantum yield of photoacid generation (ΦH+), respectively. When the energy of excited electrons was higher than that of the S2 orbital, the transition from S0 to S2 (π–π*) occurred before the C-S cleavage on S1 and the PAGs showed high ΦH+ values (0.52–0.72). The transition from S0 to S1 (π–σ*) occurred when the energy of electrons is lower than that of the S2 orbital, and the PAGs showed low ΦH+ value. The photopolymerization kinetics demonstrated that these PAGs were highly efficient cationic photoinitiators. 相似文献