Browsing Engineering (Faculty of) by Author "Li, Dongqing"
Now showing items 1-16 of 16
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Effects of ionic concentration gradient on electroosmotic flow mixing in a microchannel
Peng, Ran; Li, Dongqing (Elsevier, 2014-11-08)Effects of ionic concentration gradient on electroosmotic flow (EOF) mixing of one stream of a high concentration electrolyte solution with a stream of a low concentration electrolyte solution in a microchannel are ... -
Electrokinetic motion of single nanoparticles in single PDMS nanochannels
Peng, Ran; Li, Dongqing (Springer, 2017-01)Electrokinetic motion of single nanoparticles in single nanochannels was studied systematically by image tracking method. A novel method to fabricate PDMS-glass micro/nanochannel chips with single nanochannels was presented. ... -
Electroosmotic flow in single PDMS nanochannels
Peng, Ran; Li, Dongqing (Royal Society of Chemistry, 2016-05-23)The electroosmotic flow (EOF) velocity in single PDMS nanochannels with dimensions as small as 20 nm is investigated systematically by the current slope method in this paper. A novel method for the fabrication of single ... -
Electroosmotic flow velocity in DNA modified nanochannels
Li, Jun; Li, Dongqing (Elsevier, 2019-10-01)Electroosmotic flow (EOF) is systematically investigated in DNA grafted hard PDMS (h-PDMS) channels with size ranging from 50 nm to 2.5 μm by using the current-slope method. The effects of the DNA types, the incubation ... -
Fabrication and electrokinetic motion of electrically anisotropic Janus droplets in microchannels
Li, Dongqing; Li, Mengqi (Wiley, 2016-09-07)This paper presents experimental investigations of the fabrication and the motion of electrically anisotropic Janus droplets in a microchannel under externally applied direct current (DC) electrical field. The fabrication ... -
Fabrication of nanochannels on polystyrene surfaces
Peng, Ran; Li, Dongqing (Biomicrofluidics, 2015-05)Solvent-induced nanocrack formation on polystyrene surface is investigated experimentally. Solubility parameter and diffusion coefficient of alcohols are employed to elucidate the swelling and cracking processes as well ... -
Fabrication of polydimethylsiloxane (PDMS) nanofluidic chips with controllable channel size and spacing
Peng, Ran; Li, Dongqing (Royal Society of Chemistry, 2016-08-09)The ability to create reproducible and inexpensive nanofluidic chips is essential to the fundamental research and applications of nanofluidics. This paper presents a novel and cost-effective method for fabricating a single ... -
Focusing particles by induced charge electrokinetic flow in a microchannel
Li, Dongqing; Song, Yongxin; Wang, Chengfa; Pan, Xin-xiang; Li, Mengqi (Wiley, 2016-02-16)A novel method of sheathless particle focusing by induced charge electrokinetic flow in a microchannel is presented in this paper. By placing a pair of metal plates on the opposite walls of the channel and applying an ... -
Manipulation and separation of oil droplets by using asymmetric nano-orifice induced DC dielectrophoretic method
Zhao, Kai; Li, Dongqing (Elsevier, 2018-02-15)Emulsion droplets are versatile tools in chemical and biological fields and the separation of emulsion droplets is one of the most crucial steps in research and industry. This work developed a nano-orifice based DC ... -
Nonlinear electrokinetic motion of electrically induced Janus droplets in microchannels
Li, Mengqi; Li, Dongqing (Elsevier, 2019-03-07)The nonlinear electrokinetic motion of electrically induced Janus droplets (EIJDs) in a microchannel is studied in this paper. The EIJDs were fabricated by operating the positively charged aluminum oxide nanoparticles to ... -
A novel microfluidic resistive pulse sensor with multiple voltage input channels and a side sensing gate for particle and cell detection
Zhou, Tong; Song, Yongxin; Yuan, Yapeng; Li, Dongqing (Elsevier, 2019-04-04)Traditionally, a resistive pulse sensor (also known as Coulter counter) works by letting a particle pass through a small orifice in an electrolyte solution. The detection sensitivity mainly relies on the volume ratio of ... -
Redistribution of charged aluminum nanoparticles on oil droplets in water in response to applied electrical field
Li, Dongqing; Li, Mengqi (Springer, 2016-05-18)Janus droplets with two opposite faces of different physical or chemical properties have great potentials in many fields. This paper reports a new method for making Janus droplets by covering one side of the droplet with ... -
Redistribution of mobile surface charges of an oil droplet in water in applied electric field
Li, Dongqing; Li, Mengqi (Elsevier, 2016-10)Most researches on oil droplets immersed in aqueous solutions assume that the surface charges of oil droplets are, similar to that of solid particles, immobile and distributed uniformly under external electric field. ... -
Self-propulsion of aluminum particle-coated Janus droplet in alkaline solution
Li, Mengqi; Li, Dongqing (Elsevier, 2018-12-15)Janus droplet motion powered by gas bubbles is studied in this paper. The Janus droplets were fabricated by partially covering one side of an oil droplet with aluminum particles under gravity effect. By placing the Janus ... -
Separation of nanoparticles by a nano-orifice based DC-dielectrophoresis method in a pressure-driven flow
Zhao, Kai; Peng, Ran; Li, Dongqing (Royal Society of Chemistry, 2016-10-07)A novel DC-dielectrophoresis (DEP) method employing a pressure-driven flow for the continuous separation of micro/nano-particles is presented in this paper. To generate the DEP force, a small voltage difference is applied ... -
Vortices around Janus droplets under externally applied electrical field
Li, Dongqing; Li, Mengqi (Springer, 2016-05)In this study, the Janus droplet is an oil droplet covered with aluminum oxide nanoparticles on one side of the droplet surface under applied DC electrical field. The vortices around Janus droplets fixed on a horizontal ...