Zhong Chen

Bio: Zhong Chen is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Chemistry & Catalysis. 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.

Damage advancement behavior in braided composite structures for mini aerial vehicles

Abstract: This work provides a systematic approach to accurately predict damage progression in a composite structure subjected to bending load. Landing gear structures for unmanned aerial vehicles were fabricated from braided textile preforms and assessed for flexural behavior. A multiscale finite element analysis model was developed for analyzing the progressive damage of these structures under bending loads. Microscale and mesoscale analyses were carried out first. Subsequently, the results of microscale and mesoscale analyses were used as inputs in macroscale analyses that predicted the progressive damages in the entire landing gear structure. The numerical results were validated by experimental studies.

The Digital Field-Frequency Lock System of High-Resolution NMR Spectrometer

Abstract: To obtain a high-resolution NMR spectrum, the NMR spectrometer needs ultra-high magnetic field which is very hard to be stable. The temporal variation of magnetic field causes the change of nuclear resonance frequency from one transient to another, thus worsens the accumulative signal, and the high-resolution spectrum cannot be obtained. This paper gives the design of the digital field-frequency lock system which uses PID to implement feedback control and the way of combining internal and external loops to lock the resonance frequency, based on the phase-locked theory. The digital field-frequency lock technique can make the resonance frequency and RF frequency maintain very good relative stability, thus avoids the lines moving and eliminates the effect of the unstable magnetic field. The system can effectively improve the long-term stability of the ultra-high magnetic field and obtain high-resolution spectra.

Selection of intra- or inter-molecular multiple-quantum coherences in NMR of highly polarized solution

Abstract: In highly polarized scalar-coupled liquid systems, nuclear magnetic resonance signals from multiple-quantum coherences (MQCs) may be formed by inter-molecular dipolar and/or intra-molecular scalar couplings. Selection of specific signals can simplify the spectra, which may help us understand the underlying physical mechanisms in complex coupled spin systems. In this paper, a pulse sequence with three selective radio-frequency (RF) pulses and phase cycling was designed for this purpose. For an IpSq (p, q = 1 , 2 , 3 , … ) spin system, there are three kinds of MQC signals, which originate from intra-molecular I–S, inter-molecular I–S, and inter-molecular S–S (or I–I) coherences. These three kinds of signals can be detected separately by proper phase cycling of RF pulses, which is independent of coupling constants. The intra- and inter-molecular MQC signals can also be detected separately with specific preparation periods, but this method is sensitive to coupling constants. Our theoretical predictions are in good agreement with experimental observations. The method proposed herein can be extended to heteronuclear cases.

A review on the recent progress in superhydrophobic surfaces with special adhesions

Abstract: Superhydrophobic surfaces with special liquid adhesions have attracted a lot of interests both in academic research and in industries because of the many potential applications. This review focuses on the recent progress (within the last two years) in the fabrication, theoretical modeling, and application of superhydrophobic surfaces with various adhesive forces. In combination with our research work, in this paper, we review the research status of typical natural and biomimetic superhydrophobic surfaces, such as the preparation and applications of superhydrophobic surfaces with high/or low adhesion, superhydrophobic surfaces with controllable adhesion, superhydrophobic surfaces with directional adhesion, superhydrophobic surfaces with responsive liquid adhesion, and superhydrophilic/superhydrophobic pattern. Finally, the problems/obstacles related to practical applicability of superhydrophobic surfaces with special adhesion in real life are addressed as well.

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...