Jiyeon Choi

Bio: Jiyeon Choi is an academic researcher from University of Central Florida. The author has contributed to research in topics: Laser & Femtosecond. The author has an hindex of 18, co-authored 85 publications receiving 1094 citations. Previous affiliations of Jiyeon Choi include Centre national de la recherche scientifique & University of Bordeaux.

Flow-Electrode Capacitive Deionization Using an Aqueous Electrolyte with a High Salt Concentration

Abstract: Flow-electrode capacitive deionization (FCDI) is novel capacitive deionization (CDI) technology that exhibits continuous deionization and a high desalting efficiency. A flow-electrode with high capacitance and low resistance is required for achieving an efficient FCDI system with low energy consumption. For developing high-performance flow-electrode, studies should be conducted considering porous materials, conductive additives, and electrolytes constituting the flow-electrode. Here, we evaluated the desalting performances of flow-electrodes with spherical activated carbon and aqueous electrolytes containing various concentrations of NaCl in the FCDI unit cell for confirming the effect of salt concentration on the electrolyte of a flow-electrode on desalting efficiency. We verified the necessity of a moderate amount of salt in the flow-electrode for compensating for the reduction in the performance of the flow-electrode, attributed to the resistance of water used as the electrolyte. Simultaneously, we con...

A novel three-dimensional desalination system utilizing honeycomb-shaped lattice structures for flow-electrode capacitive deionization

Abstract: A highly compact and scalable three-dimensional desalination cell was realized by utilizing honeycomb-shaped porous lattice scaffolds. It did not require a free-standing ion exchange membrane and a thick current collector. Furthermore, the porous structure can act as a structural scaffold. Therefore, it can be readily scaled-up in three dimensions allowing enhanced salt removal capacity. This provides great potential for scale-up and commercialization of desalination using the capacitive deionization technology.

Surface-modified spherical activated carbon for high carbon loading and its desalting performance in flow-electrode capacitive deionization

Abstract: We have synthesized a new type of activated carbon (AC) containing ion-selective functional groups, trimethylammonium (AC-N) for anodes and sulfonate (AC-S) for cathodes, for high carbon loading of flow-electrodes. The AC-N and AC-S were partially covered with a 50 nm-thick polymer layer and their surfaces became more hydrophilic than that of bare AC. In the case of bare AC, the maximum carbon concentration in the flow electrodes was 10%, while in the case of the surface-modified AC (AC-N and AC-S), it increased to a maximum of 35% and decreased the viscosity due to the electrostatic repulsion. Moreover, with the increase in carbon concentration, the salt removal efficiencies were improved from 8.2% to 27.7%. This increase in efficiency was attributed to the formation of percolating networks, which occurred because of high carbon loading. The resulting improvement in electronic conductivity at higher loading led to a higher current, and thus an improved salt removal efficiency. Therefore, we expect that the surface-modified AC electrode can be used as a dispersant for hydrophobic AC particles in aqueous solution, as well as in flow electrodes to improve desalting performance in FCDI systems.

3D Patterning at the Nanoscale of Fluorescent Emitters in Glass

Abstract: Three-dimensional fluorescent nanostructures are photoinduced by a near-infrared high repetition rate femtosecond laser in a silver-containing femto-photoluminescent glass. By adjusting the laser dose (fluence, number of pulses, and repetition rate), these stabilized intense fluorescent structures, composed of silver clusters, can be achieved with a perfect control of the luminescence intensity, the emission spectrum, and the spatial distribution at the nanometer scale. This novel approach opens the way to the fabrication of stable fluorescent nanostructures in three dimensions in glass for applications in photonics and optical data storage.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Ultracapacitors: Why, How, and Where is the Technology

Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Fluorescent silver nanoclusters

Abstract: Silver nanoclusters are a class of fluorophores with attractive features, including brightness, photostability and subnanometer size. In this review we overview the different scaffolds that are used as stabilizer for silver nanoclusters (e.g. polymers, dendrimers, DNA oligomers, cryogenic noble gas matrixes, inorganic glasses, zeolites and nanoparticles), and we briefly discuss the recent advances.

Developing luminescent silver nanodots for biological applications

Abstract: Though creation and characterization of water soluble luminescent silver nanodots were achieved only in the past decade, a large variety of emitters in diverse scaffolds have been reported. Photophysical properties approach those of semiconductor quantum dots, but relatively small sizes are retained. Because of these properties, silver nanodots are finding ever-expanding roles as probes and biolabels. In this critical review we revisit the studies on silver nanodots in inert environments and in aqueous solutions. The recent advances detailing their chemical and physical properties of silver nanodots are highlighted with an effort to decipher the relations between their chemical/photophysical properties and their structures. The primary results about their biological applications are discussed here as well, especially relating to their chemical and photophysical behaviours in biological environments (216 references).