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.

Immobilization of well-dispersed Ag nanoparticles on calcium niobate nanosheets as highly active catalyst towards reduction of 4-nitrophenol

Abstract: Ag nanoparticles were successfully deposited onto calcium niobate nanosheets using the electrostatic self-assembly method, followed by UV irradiation photoreduction. Various characterization techniques including XRD, SEM, HRTEM, BET and XPS have been utilized to study the material crystalline structure, microstructure, pore size and surface properties. Silver nanoparticles in the size range of 2–8 nm are well dispersed on the surface of the calcium niobate nanosheets. The as-synthesized Ag-Ca2Nb3O10 was a mesoporous material with a broad pore size distribution. Ag-Ca2Nb3O10 exhibited remarkable catalytic activity for the reduction of 4-nitrophenol (4-NP) by NaBH4 solution under ambient conditions, and no obvious activity degradation was observed after 5 cycles of durability test. The reduction has a pseudo-first-order rate constant of 18.01 × 10−3 s − 1 and an activity parameter of 6.00 s − 1 g − 1. The activation energy (Ea) of the reduction reaction was calculated as 59.63 kJ mol−1. The catalyst was recycled several times without any significant catalytic activity loss. This work provides a facile route to synthesize a highly efficient catalyst for the reduction of organic pollutants.

Temperature-Dependent Carrier Recombination and Efficiency Droop of AlGaN Deep Ultraviolet Light-Emitting Diodes

Abstract: We investigate temperature-dependent carrier transfer and efficiency droop on AlGaN-based deep ultraviolet light-emitting diodes. The Shockley-Read-Hall (SRH) recombination and carrier leakage are highly associated with the poor thermal stability. The existence of Auger recombination and carrier leakage is identified by the m-power method. A modified ABC model with an additional term f ( n ) related to carrier leakage is employed to analyze the evolution of multiple recombination mechanisms. The SRH process strongly suppresses both Auger recombination and carrier leakage at low currents. At high currents, the latter two processes are responsible for the efficiency droop and exhibit an anti-correlation upon temperature.

An Efficient Method for Adventitious Root Induction from Stem Segments of Brassica Species

Abstract: Plant propagation via in vitro culture is a very laborious and time consuming process. The growth cycle of some of the crop species is slow even in the field and the consistent commercial production is hard to maintain. Enhanced methods of reduced cost, materials and labour significantly impact the research and commercial production of field crops. In our studies, stem-segment explants of Brassica species were found to regenerate adventitious roots (AR) in aeroponic systems in less than a week. As such, the efficiency of root regeneration from stem explants of six cultivar varieties of Brassica spp were tested without the use of any plant hormones. New roots and shoots were regenerated from Brassica alboglabra (Kai Lan), Brassica oleracea var. acephala (purple kale), Brassica rapa L. ssp. Chinensis L (Pai Tsai, Nai Bai C and Nai Bai T) explants after 3 to 5 days of growing under 20±2°C cool root zone temperature (C-RZT) and 4 to 7 days in 30±2°C ambient root zone temperature (A-RZT). However, Brassica rapa nipposinica (Mizuna) explants were only able to regenerate in C-RZT. All regenerated explants were able to develop into whole plants, with higher biomass obtained from plants that grown in C-RZT. Moreover, explants from both RZTs produced higher biomass than plants grown from seeds (control plants). Regeneration efficiency was affected by RZTs and explant cuttings of donor plants. Photosynthetic CO2 assimilation rate (Asat) and stomatal conductance (gs sat) were not significantly differentiated between plants derived from seeds and explants at both RZTs. As such, this method of regeneration using aeroponics is suitable for all commercial cultivars studied. The findings of this study could be applicable in the mass propagation of vegetable crops, shortening the growth cycle as seed germination and seedling development periods can be eliminated.

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...