Particuology
·
2015
·
IF 2.11
Haifeng Jiang,Qianghui Xu,Chao Huang,Lin Shi
Nanofluids were prepared by dispersing Cu nanoparticles (∼20 nm) in n-tetradecane by a two-step method. The effective thermal conductivity was measured for various nanoparticle volume fractions (0.0001–0.02) and temperatures (306.22–452.66 K). The experimental data compares well with the Jang and Choi model. The thermal conductivity enhancement was lower above 391.06 K than for that between 306.22 and 360.77 K. The interfacial thermal resistance increased with increasing temperature. The effective thermal conductivity enhancement was greater than that obtained with a more viscous fluid as the base media at 452.66 K because of nanoconvection induced by nanoparticle Brownian motion at high temperature.
研究领域:
材料科学
·
热物理学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Xiaoping Li,Jiaxin Pan,Jinwen Shi,Yanlin Chai,Songwei Hu,Qiaorong Han,Yanming Zhang,Xianwen Li,Dengwei Jing
Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO 2 nanoparticles to various polymer polyacrylamide (PAM) solutions were examined in this work. The optimal combination of SiO 2 nanoparticles with cationic polyacrylamide was confirmed. Interestingly, the addition of SiO 2 nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO 2 nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.
研究领域:
流体力学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
·
2018
·Vol. 51
·期 9
·095401
·
IF 2.119
Shuofeng Liang,Leicheng Yin,ZhenZhen Zhang,Jiangying Xia,Kang Xie,Gang Zou,Zhijia Hu,Qijin Zhang
The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10−5 s to 1.61 × 10−4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.
研究领域:
光学
·
物理学
·
统计力学
·
光子学
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2016
·Vol. 29
·期 3
·1603374
·
IF 18.96
Chuanrui Chen,Fangzhi Mou,Leilei Xu,Shaofei Wang,Jianguo Guan,Zunpeng Feng,Quanwei Wang,Lei Kong,Wei Li,Joseph Wang,Qingjie Zhang
Graphical Intelligent photoresponsive isotropic semiconductor micromotors are developed by taking advantage of the limited penetration depth of light to induce asymmetrical surface chemical reactions. Independent of the Brownian motion of themselves, the as-proposed isotropic micromotors are able to continuously move with both motion direction and speed just controlled by light, as well as precisely manipulate particles for nanoengineering.
研究领域:
材料科学
·
纳米技术
·
光化学
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Jian Lv,Xiao-Yuan Wang,Xin-Yue Zhou,Da-Wei Li,Ruo-Can Qian
Targeted delivery and labeling of single living cells in heterogeneous cell populations are of great importance to understand the molecular biology and physiological functions of individual cells. However, it remains challenging to perfuse fluorescence markers into single living cells with high spatial and temporal resolution without interfering neighboring cells. Here, we report a single cell perfusion and fluorescence labeling strategy based on nanoscale glass nanopipettes. With the nanoscale tip hole of 100 nm, the use of nanopipettes allows special perfusion and high-resolution fluorescence labeling of different subcellular regions in single cells of interest. The dynamic of various fluorescent probes has been studied to exemplify the feasibility of nanopipette-dependent targeted delivery. According to experimental results, the cytoplasm labeling of Sulfo-Cyanine5 and fluorescein isothiocyanate is mainly based on the Brownian movement due to the dyes themselves and does not have a targeting ability, while the nucleus labeling of 4′,6-diamidino-2-phenylindole (DAPI) is originated from the adsorption between DAPI and DNA in the nucleus. From the finite element simulation, the precise manipulation of intracellular delivery is realized by controlling the electro-osmotic flow inside the nanopipettes, and the different delivery modes between nontargeting dyes and nucleus-targeting dyes were compared, showcasing the valuable ability of nanopipette-based method for the analysis of specially defined subcellular regions and the potential applications for single cell surgery, subcellular manipulation, and gene delivery.
研究领域:
细胞生物学
·
分子生物学
·
生物物理学
✓ 已验证
DOI
PubMed
高影响因子
Advanced Intelligent Systems
·
2024
·
IF 6.8
Yang Liu,Ying Feng,Linlin Liu,Miao An,Huaming Yang
Micro/nanorobots (MNRs) are promising for biomedical applications due to their unconstrained nature and small enough size to pass through many tiny environments. However, the efficient movement of MNRs in liquid environments is still a challenge due to the low Reynolds number environment and the Brownian motion of particles. Herein, emerging MNRs with hydrogel-loaded magnetic particles are designed. The proposed hydrogel MNRs (HMNRs) exhibit biocompatible and controllable characteristics. The motion controllability of HMNRs is realized by applying oscillating magnetic field and customized magnetic field. Experimentally, it is demonstrated that the HMNR swarms driven by the oscillating magnetic field exhibit a faster motion speed than the MNR swarms composed of magnetic particles. The HMNRs show precise controllability of the movement in the complex pipeline under the control of customized magnetic field. This method can offer a more benign approach to the general production of HMNRs for biological applications.
研究领域:
生物医学工程
·
纳米技术
·
机器人学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2019
·
IF 3.556
Hongyan Sun,Ruyuan Jiao,Hui Xu,Guangyu An,Dongsheng Wang
In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles , were employed to investigate the effect of particle size on coagulation mechanisms with varying coagulation parameters. Results showed that it is easier for nanoparticles to cause self-aggregation because of Brownian motion, while interception and sedimentation are the mainly physical processes affecting particle transport for microparticles, so they are more stable and disperse more easily. The particle size distribution and particle concentration had distinct influence on the coagulation mechanisms. Under neutral conditions, as the amount of coagulant increased, the coagulation mechanism for nanoparticles changed from charge neutralization to sweep flocculation and the nanoparticles became destabilized, re-stabilized and again destabilized. For microparticles, although the coagulation mechanism was the same as that of nanoparticles, the increased rate of aluminum hydroxide precipitation exceeded the adsorption of incipiently formed soluble alum species, resulting in the disappearance of the re-stabilization zone. Under acidic conditions, Brownian motion dominates for nanoparticles at low particle concentrations, while sweep flocculation is predominant at high particle concentrations. As for microparticles, charge neutralization and sweep flocculation are the mechanisms for low and high particle concentrations respectively. Under alkaline condition, although the mechanisms for both nano- and microparticles are the same, the morphology of flocs and the kinetics of floc formation are different. At low particle concentrations, nanoparticles have larger growth rate and final size of flocs, while at high particle concentrations, nanoparticles have higher fractal dimension and recovery factors.
研究领域:
环境科学
·
化学工程
·
胶体与表面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Rui Xu,Xiangwen Zhou,Tianyin Shen,Changsheng Deng,Shaochang Hao,Xingyu Zhao,Jianjun Li,Bing Liu,Jingtao Ma
Nanocrystalline materials with excellent properties are of great interest, but little is known about how to maintain grain size uniformity, which is essential for the reliability of nanomaterials . A fascinating question is whether it is possible to achieve a narrow size distribution of colloidal clusters in the gel. The nanocrystalline materials could be prepared by sintering the gel. Based on the above ideas, the growth mechanism of colloidal particles in the zirconium-based sol-gel transition is studied. The study showed that the primary zirconium hydroxide colloidal particles based on zirconium tetramers would aggregate into clusters of about 70 nm due to the Brownian motion. The clusters would form the Zr-O-Zr bonds and the three-dimensional gel network structure. The three-dimensional gel network could restrict the movement of free water molecules, making the zirconium sol instantly transform into the zirconium gel. The aging temperature would not affect the size of the colloidal clusters in the zirconium gel. Therefore, the uniform nanocrystalline zirconia could be prepared by sintering zirconium gel, which demonstrated the superiority of the internal gelation process for preparing nanocrystalline materials.
研究领域:
材料科学
·
化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2021
·
IF 3.882
Yuehua Zhao,Yuyuan Lu,Dapeng Wang
Emulsions stabilized by both nanoparticles and surfactants often display longer shelf life than those stabilized by nanoparticles or surfactants alone. Although numerous works have been conducted to understand the effect of nanoparticles and surfactants on the variation of interfacial tension, little is known about interfacial diffusion when both nanoparticles and surfactants are present at interfaces. In this work, we used single-particle fluorescence tracking to study the lateral diffusion of individual hydrophobic nanoparticles at hexane–glycerol interfaces adsorbed by different amounts of nonionic surfactants. When the surfactant concentration is over a threshold, we found that the nanoparticle diffusion exhibits a two-regime behavior involving short-time Brownian and the emergence of subdiffusive, non-Gaussian, and dynamically anticorrelated diffusion in the long lag time regime. A stepwise analysis rationalized diffusion in different lag time regimes, leading to a mechanistic interpretation regarding the two-regime behavior. These results could provide insight into the understanding of the synergistic effect for the surfactant-assistant Pickering emulsion.
研究领域:
胶体科学
·
表面化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2019
·
IF 13.903
Hua Sun,Zonghua Wang,Yan He
Polymer network gels usually exhibit spatial heterogeneity of local defects and cross-link density, which can affect their elasticity on the microscopic scale differently. The ability to evaluate the formation and distribution of these heterogeneities is important for guiding the application of gels in biology, medicine, and separation science. Previously, it has been reported that single-particle tracking based microrheology could provide local properties of gel networks with high resolution; however, the particle probes have been limited to spherical micro/nanotracers undergoing translational motions. In this work, we used single gold nanorods (AuNRs) as rotational microrheology probes to study the polyacrylamide gelation process by dual-channel polarization dark-field microscopy. The AuNRs were in Brownian motion during the initial stages of the gelation. As the reaction continues, individual AuNRs are confined locally and almost lost translational motion, but still maintained rotational motion. As the reaction proceeded further, the rotation state of the AuNRs gradually changed from free rotation in 3D to restricted rotation in 2D and eventually stopped completely. The appearance of the intermediate 2D plane indicated the existence of localized anisotropic compression of the gel during the heterogeneous gelation process. Our method can be further applied to investigate the formation of different polymer gels and a wide variety of heterogeneous biophysical and soft material systems.
研究领域:
材料科学
·
生物物理学
·
软物质物理
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）