COMPOSITES COMMUNICATIONS
·
2019
·
IF 0
Zhihao Sun,Zhaoqian Yan,Rui Yin,Xiaoshuai Huang,Kaicheng Yue,Anran Li,Lei Qian
With tunable negative permittivity, flexible and collapsible films composed of polyvinylpyrrolidone modified graphene and poly(vinylidene fluoride) were fabricated by solution casting method. Interestingly, a secondary percolation behavior was observed from σ ac , and two percolation thresholds ranged from 3.75 to 6.25 wt% and 12.5 to 18.75 wt%, respectively. Meanwhile, the results indicated that the obtained composite films achieved negative permittivity at a lower GR content (3.75 wt%), which was ascribed to better dispersion of the modified GR in the matrix. The negative dielectric curves could be well in accordance with Lorentz model and Drude model, respectively. It was also first discovered that different types of negative dielectric behavior corresponded well to the two percolation phenomena of σ ac , which was ascribed to the different microstructures.
研究领域:
材料科学
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电子工程
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产品关联
DOI
POLYMER
·
2019
·
IF 3.771
Jing Shao,Jing-Wen Wang,Da-Nian Liu,Lei Wei,Sen-Qiang Wu,Hua Ren
A high permittivity acrylic resin (AE)-based percolative composite with two-dimensional (2D) MXene nanosheets as the conducting fillers was fabricated. The Ti 3 C 2 T x MXene nanosheets were delaminated (referred to d-Ti 3 C 2 T x ) and then modified with polypyrrole (PPy). The d-Ti 3 C 2 T x /AE and PPy- d -Ti 3 C 2 T x /AE composite films with different filler loadings were obtained with the solution casting method. The dielectric constants of 6.36 vol %d-Ti 3 C 2 T x /AE and 5.98 vol %PPy- d -Ti 3 C 2 T x /AE are 493 and 265 at 10 2 Hz, respectively, approximately 140 and 75 times of pure AE (3.5). Meanwhile, the dielectric loss of PPy- d -Ti 3 C 2 T x /AE composite maintains at a relative low level (0.23 at 10 3 Hz) when the volume fraction of PPy- d -Ti 3 C 2 T x gets close to the percolation threshold ( f c = 6.39). The large enhancement in dielectric constant of composite is closely relevant to the microcapacitor effect and the free charge accumulation caused by the formation of interfaces between the conducting fillers and polymer matrix .
研究领域:
材料科学
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电气工程
·
纳米技术
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产品关联
DOI
高影响因子
iScience
·
2022
·
IF 6.107
Peiliu Li,Xianfu Huang,Ya-Pu Zhao
Viscous fingering is an extensively observed phenomenon in porous media or Hele-Shaw cells. In general, this instability is particularly difficult to control for given fluids and geometries. Therefore, investigating a control method of viscous fingering is quite attractive. Here, we present that electro-visco-fingering (EVF) in fluids with different relative permittivity shows a controllable performance under electric fields. The theoretical model is established from the perspective of force analysis to indicate that active control of EVF is achieved by the competition between the Maxwell stress jump and hydrostatic pressure gradient. In addition, an Electric Control number (E C ) is adopted to characterize the electric effect on EVF and experimentally confirmed for broad ranges of flow rates and voltages. Unlike the electro-osmotic flow, this method shows a considerable achievement in energy efficiency. Our work provides a new way to actively control viscous fingering and opens new routes for applications of interfacial instabilities.
研究领域:
流体力学
·
应用物理
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DOI
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 6
·517
·
IF 4.4
Yunyu Sun,Hao Wang,Jiwei Jiang,Hui Zhang,Limei Liu,Keying Zhang,Bo Song,Bin Dong
Inspired by the collective behaviors of active systems in nature, the collective behavior of micromotors has attracted more and more attention in recent years. However, little attention has been paid to the collective behavior of the immobilized micromotor, i.e., the micropump. In this paper, a unique pentacene-based micropump is reported, which demonstrates dynamic collective behavior activated by white light irradiation. The light irradiation may generate the photochemical reactions between pentacene and water, leading to the electroosmotic flow. As a result, this micropump is capable of pumping the surrounding solution inward along the substrate surface based on the electroosmosis mechanism. Intriguingly, the inward pumping causes the agglomeration of the tracer particles on the surface of the micropump. In addition, the aggregation can migrate following the change in the light irradiation position between two adjacent micropumps. Based on the aggregating and migrating behaviors of this pentacene-based micropump, we have achieved the conductivity restoration of the cracked circuit.
研究领域:
材料科学
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生物仿生学
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纳米技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2018
·
IF 3.794
Rui Yin,Yubai Zhang,Wen Zhao,Xiaoshuai Huang,Xiaomin Li,Lei Qian
Graphene platelets/aluminium nitride (GPLs/AlN) metacomposites with double percolation property of thermal and electrical conductivity were successfully fabricated by spark plasma sintering . Microstructures and phase composition of the GPLs/AlN metacomposites were investigated by field emission scanning electron microscopy , X-ray diffraction and Raman spectroscopy . With increase of the GPLs contents, the double percolation property of thermal (19.27 wt% GPL) and electrical conductivity (19.03 wt% GPL) was found. Moreover, the negative permittivity behavior was also observed when the GPLs content reached 19.50 wt%, which was attributed to the formation of continuous GPLs networks. Finally, the equivalent circuit models were used to analyze the negative permittivity behavior. As the reactance ( Z′′ ) converted from negative to positive, the inductors were introduced into the equivalent circuit models, and the GPLs/AlN metacomposites went through the capacitive-inductive transition with the increasing GPLs content, corresponding to the negative permittivity behavior.
研究领域:
材料科学
·
物理学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Zhao Cui,Meng Zhang,Yang Yuan,Hui Jia,Huu Hao Ngo,Jie Wang
The focus of this study is on the enhanced concentration effect of the pump effect in forward osmosis (FO) and electroosmotic integrated chip. The study investigates the strengthening effect of the FO process, driven by the pump effect, on the electroosmotic flow process under the same energy consumption, using low-concentration heavy metal ions (Cr 3+ ) as the target enrichment. In the chip system, the pump effect, caused by capillary pressure difference, successfully replaces the osmotic pressure of the draw solution as a new driving force for the FO process. By adjusting the size and number of channels and avoiding errors, the study achieves the highest efficiency of the FO process in the chip, concentrating Cr 3+ from 1.26 × 10 −4 mol/L to 8.01 × 10 −4 mol/L (6.4 times) within 32 min. Excluding the influence of the electrokinetic (EK) limit of low-concentration samples, the concentration efficiency of an individual electroosmotic chip in this study is positively correlated with cross-nanochannel voltage (V cn ). The integrated FO and electroosmosis chip reduce the duration required to concentrate 50 mL Cr 3+ sample to the limit from 90 min to 16 min (5.6 times) compared to the single electroosmotic process. Furthermore, a series of Cr 3+ samples with concentrations below the detection limit of the UV–vis spectrophotometer were concentrated and detected by the integrated chip. The results indicate that the concentration limit of the FO-electroosmotic integrated chip for samples can increase the detection limit of Cr 3+ from 1.37 × 10 −4 mol/L to 3.67 × 10 −6 mol/L.
研究领域:
环境科学
·
分析化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2023
·
IF 5.2
Shuai Yuan,Mingyong Zhou,Xijiang Liu,Bingyan Jiang
The coupling of pressure-driven flow (PDF) and electroosmotic flow (EOF) has been widely applied in the field of microfluidics. However, the adverse effects of pressure induced by PDF on EOF in a confined space cannot be ignored. Herein, the interactions of these two streams when the Reynolds number ( Re ) varies from 0.1 to 10 are systematically explored through numerical simulations to gain an in-depth understanding of the mechanism of the pressure effect on mass species transport and to generate optimal separation of samples. The simulation results show that the length of the sample increases linearly and the molecular diffusion is accelerated due to the pressure effect caused by the EOF channel structure and PDF extrusion, which reduces the separation quality and even leads to the failure of electrophoresis . However, the deformation of the sample cannot be effectively resisted by increasing the applied voltage . A better separation effect can be obtained only when Re =0.1. To surmount the above disadvantages, a novel porous polymer plug with pores smaller than 5 μm that provides a region that has high flow resistance but allows the electromigration of charged analytes is established in the EOF channel. The experimental results show that this plug can effectively neutralize the EOF outlet pressure when Re ≤5. The shape of the sample is not distorted and the maximum gray values decreased by 26%, 30% and 49% respectively in 7 s when Re =0.1, 1 and 5, which are much better than the results without the plug.
研究领域:
微流控技术
·
分析化学
·
生物工程
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产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Ruo-Can Qian,Jian Lv,Yi-Tao Long
Recently, a variety of strategies have been developed for single-cell detection. However, the precise probing of the given area at single-cell level is still a challenge. Here, we put forward a rapid and targeted imaging approach for the mapping of subcelluar domains, which realizes the precise injection of multifluorescence into a single living cell via an ultrasmall quartz capillary nanopipette (∼100 nm) and can successfully transport different fluorescent probe molecules to the pointing subcellullar area around the tip in the cytoplasm within 20 s. This method is also applied for monitoring the loss of intracellular mitochondrial membrane potential under the treatment of metformin in a single MCF-7 breast cancer cell. The major driven force in the nanopipette, electroosmotic flow, is evaluated by a theory calculation method and finite element simulations, and the solution indicates a confined solute distribution profile around the tip within the working range. Overall, the nanopipette approach realizes the precise and simultaneous delivery of multiple probe molecules into the single living cell through the electroosmotically modulated, nondestructive, and one-step injection, which is especially powerful and convenient for multichannel single-cell imaging and monitoring, indicating favorable potential for understanding, monitoring, and controlling the biological processes from the single cell to subcellular organelles.
研究领域:
细胞生物学
·
生物物理学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Xin Qian,Lan Xia,Baian Ji,Yike Huang,Zhining Xia
To improve separation efficiency and address the adverse effects of electro-osmosis, a coated capillary was used to shield the electroosmosis. A nanoflow pump was used to control the flow of the electrophoretic medium, thereby extending the time of the electrophoretic action. Furthermore, by using a coated capillary that is only 10 cm long as the separation column, the electric field strength could reach as high as 250 V/mm. These strategies strengthened the interaction between the enantiomers and the chiral selector, thus enhancing the resolution of enantiomers. As a result, complete separation of the amlodipine enantiomers could be achieved by halting the electrophoretic medium. Further extending the duration of flow stoppage can increase the resolution several-fold. The method established in this study exhibits excellent accuracy and precision. Despite experiencing a long period of flow stoppage, the relative standard deviations of both migration time and resolution remain less than 2%. This method not only remarkably enhanced the resolution of amlodipine enantiomers but also demonstrated broad applicability in separating other chiral enantiomers, particularly for those substances that are difficult to separate using conventional capillary electrophoresis.
研究领域:
分析化学
·
药物分析
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2018
·
IF 6.653
Lei Liu,Ke Zhang
Developing novel methods for the removal of heavy-metal ions from wastewater with low costs, special selectivity and high efficiency is quite important in water restoration and comprehensive ecological improvement. In this work, a nanopore-based strategy was suggested and related segregation apparatus was built to separate multiple heavy-metal ions in water by selective complexation. The results indicated that the prioritization of the selecting order for the complexing agent (thiacalix[4]arene-p-tetrasulfonate (TCAS)) to heavy-metal ions was Cu(II) > Cd(II) > Pb(II) > Ba(II). Meanwhile, higher driven voltage corresponded to a faster separation speed, while it could cause the decomposition of complexed heavy-metal ions when excessed the threshold. On the other hand, pH value would affect the hydrolysis of heavy-metal ions, the complexation of the calixarene to the heavy-metal ions and the speed of the electroosmotic flow. In our experiments, the maximum separation efficiency was achieved when the driven voltage was 1.5 V and the pH value was 5.0, corresponding to the best separation rate of 94.8%, 95.2%, 92.8%, 93.6%, for Cu(II), Cd(II), Pb(II) and Ba(II), respectively.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Minerals
·
2019
·Vol. 9
·期 1
·44
·
IF 2.25
Lidong Dai,Haiying Hu,Wenqing Sun,Heping Li,Changcai Liu,Mengqi Wang
The electrical conductivity of dry sintered olivine aggregates with various contents of magnetite (0, 3, 5, 7, 10, 20, and 100 vol. %) was measured at temperatures of 873–1273 K and a pressure of 2.0 GPa within a frequency range of 0.1–106Hz. The changes of the electrical conductivity of the samples with temperature followed an Arrhenius relation. The electrical conductivity of the sintered olivine aggregates increased as the magnetite-bearing content increased, and the activation enthalpy decreased, accordingly. When the content of interconnected magnetite was higher than the percolation threshold (~5 vol. %), the electrical conductivity of the samples was markedly enhanced. As the pressure increased from 1.0 to 3.0 GPa, the electrical conductivity of the magnetite-free olivine aggregates decreased, whereas the electrical conductivity of the 5 vol. % magnetite-bearing sample increased. Furthermore, the activation energy and activation volume of the 5 vol. % magnetite-bearing sintered olivine aggregates at atmospheric pressure were calculated to be 0.16 ± 0.04 eV and −1.50 ± 0.04 cm3/mole respectively. Due to the high value of percolation threshold (~5 vol. %) in the magnetite impurity sample, our present results suggest that regional high conductivity anomalies in the deep Earth’s interior cannot be explained by the presence of the interconnected magnetite-bearing olivine aggregates.Keywords:electrical conductivity;magnetite;olivine aggregates;percolation threshold;high temperature and high pressure
研究领域:
地球物理学
·
矿物学
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产品关联
DOI
高影响因子
POLYMER TESTING
·
2020
·
IF 3.275
Lei Wei,Jing-Wen Wang,Xin-Hua Gao,Hou-Qing Wang,Xin-Zhu Wang,Hua Ren
Bimodal network composite was prepared using a two-step method containing graphene modified by γ-(2, 3-epoxypropoxy) propyl trimethoxysilane (KH560), short chain poly(dimethyl siloxane) (C S -PDMS) and long chain poly(dimethyl siloxane) filled with treated fumed silica (C L -h-PDMS). A series of composites with different filler contents (including reduced graphene oxide and reduced graphene oxide grafted with KH560, referred to rGO and KrGO, respectively) were prepared to explore their percolation thresholds ( fc ). We discover that the dielectric constant and loss of 1.32 vol% KrGO/h-PDMS composite were 18.8 and 0.13 at 10 2 Hz before fc , respectively, which was 2.1 and 0.12 times that of rGO/h-PDMS, and 6.6 and 2.1 times that of pure h-PDMS. The origin is that KH560 insulting layer increases the interlayer distance of graphene sheets to cut down the leakage current . In addition, the modulus of 1.32 vol% KrGO/h-PDMS is less than 3 MPa.
研究领域:
材料科学
·
电气工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）