Zhong Chen

Bio: Zhong Chen is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Medicine & Chemistry. The author has an hindex of 80, co-authored 1000 publications receiving 28171 citations. Previous affiliations of Zhong Chen include Institute of High Performance Computing Singapore & National Institute of Education.

Carbothermal Synthesis of Nano-iron-carbon Composites for Arsenate Removal from High-arsenic Acid Wastewater

Abstract: The current carbothermal method involves impregnation and reduction of ferric salt with the problems of low product activity and high cost, limiting the large-scale production and application of nano-zero-valent iron (nZVI). In this work, the nano-iron-carbon composites (CB-nZVI) were successfully synthesized at a high efficiency, low consumption and batch production process and showed a rapid and efficient As(V) removal from high-arsenic acid wastewater (pH<2 and As(V)> 5 g/L). More than 99.77% As(V) was removed by CB-nZVI under optimum reaction conditions of pH 1.7, initial As(V) concentration 5 g/L and nZVI dosage 11 g/L at 40 ℃ with approximately 11 mg/L As(V) still remained in the filtrate. A novel continuous two-stage treatment process was proposed with only 0.12 mg/L As(V) remained in the filtrate, which met the demands specified in Emission Standard of Pollutants for the Sulfuric Acid Industry issued by Ministry of Environmental Protection of China (GB26132–2010), and solid wastes were greatly reduced at the same time. The iron species distributed on the CB-nZVI core-shell structure possessed a high chemical reduction potential gradient driving force which resulted in the adsorbed As(V) would further be reduced to As(III) and As(0) and then diffusing across the thin oxide layer, leading to accumulating or immobilizing the arsenic at the CB-nZVI. Moreover, strongly acidic condition and Fe/C micro-electrolysis could accelerate the corrosion of CB-nZVI and generate iron oxides for As(V) adsorption. These results suggested that CB-nZVI has great potential for the disposal of strongly acidic wastewater with high concentration in the smelting industry.

Stability of Hybrid Organic-Inorganic Perovskite CH3NH3PbBr3 Nanocrystals under Co-Stresses of UV Light Illumination and Temperature

Abstract: Hybrid organic–inorganic metal halide perovskite nanocrystals (NCs) are among the candidates for color conversion materials in displays, especially in NC-based micro-light-emitting diode (micro-LED) displays. However, these NCs are still lacking long-term stability, which has hindered their large-scale applications. We mimic the working conditions, which include ultraviolet light illumination at 323 K and three different types of atmosphere (N2, vacuum, and air), respectively, to investigate the stability of CH3NH3PbBr3 NCs embedded in the polyvinylidene fluoride matrix. X-ray diffraction results indicate the generation of NH4Pb2Br5, which is produced from the encapsulated CH3NH3PbBr3 NCs in all three atmospheres, and the decomposition generates a large amount of accompanying interface defects at the surface area of NCs, resulting in the significant decrease of the photoluminescence (PL) intensity. This work highlights the stability-related mechanism of CH3NH3PbBr3 NCs under combined external stresses that mimic operating conditions. In addition, this work also suggests a new method for conducting aging tests and contributes to developing effective routes towards higher stability of perovskite NCs.

Nanostructured photoelectrochemical solar cells with polyaniline nanobelts acting as hole conductors

Abstract: Nanostructured photoelectrochemical solar cells have been prepared by combining a Sb2S3-sensitized photoactive electrode, polyaniline nanobelts, and a Ag counter electrode to form a layered structure. Here, Sb2S3 acts as an absorbing semiconductor, and polyaniline acts as both a hole conductor and light absorber (a hole-conducting dye). Via the optimization that eventually determines the chemical bath deposition duration to be 3 h, the cell shows a high photovoltaic performance with 7.05 mA/cm2-short-circuit current density, 0.695 V-open-circuit voltage, 0.457 fill factor, and 2.24 % power conversion efficiency. The prepared devices are stable under room light in ambient conditions (even without encapsulation).

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Principles of Neural Science

Abstract: I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...