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.

Determining Two-Dimensional Phosphor Surface Temperature Distribution of Phosphor-Coated LEDs Based on Hyper-Spectral Imaging

Abstract: We present a high-resolution non-contact method for the measurement of two-dimensional (2D) phosphor surface temperature distribution (PSTD) of phosphor-coated light-emitting diodes (pc-LEDs) based on advanced hyper-spectral imaging technology. The studied pc-LEDs with a surface-mounted device structure are mainly consisted of blue InGaN/GaN-based LED chips (with a spectral emission at about 456 nm), red (Sr,Ca)AlSiN3: Eu2+ phosphors (with a spectral emission at around 623 nm), and transparent silicone gels. Experimental temperature results are compared with those of micro-thermocouple ( $\mu $ -TC) and infrared thermal imaging (TI), and fairly good agreements can be noticed. However, the spatial resolution of this proposed method is more than one order of magnitude higher than that of TI method, and the proposed method provides more detailed surface temperature information of phosphors than the latter. Therefore, we believe that this proposed method can serve as useful tools for the non-contact measurement of PSTD in pc-LEDs with or without optics lens.

Investigations on the Effects of NMR Experimental Conditions in Human Urine and Serum Metabolic Profiles

Abstract: Studying on the effects of the experimental conditions to the spectra data are very important for NMR-based metobonomics since the resonance signals were sensitive to the experimental conditions. In this paper, NOEPER and NOEPER-CPMG pulse sequences are adopted to acquire the 1H NMR spectra of the human urine and serum samples respectively, and two important parameters, i.e., the experimental temperature and the saturation power of NOEPER sequence, are investigated. Resonance peaks shifting and signal intensity changing can be observed in both the urine spectra and the serum spectra when the experimental temperature was changed. For example, intensity of resonance signal of LDL, VLDL, valine and choline would increase obviously in the serum spectra with the experimental temperature increasing. Those evidences implied that it is important to acquire the 1H NMR spectra of the samples in the same temperature. In addition, water suppression profiles of the NOEPER pulse sequence are obtained with several different values of saturation power, in which signals whose chemical shifts are closed to that of water would decrease their intensity with the saturation power rising. Those results demonstrate that trade-off between the water suppression and signal decrease must be taken into consideration. As a matter of experience, lower saturation power is recommended if the water signal has been suppressed enough.

High Efficient Reconstruction of Single-shot T2 Mapping from OverLapping-Echo Detachment Planar Imaging Based on Deep Residual Network.

Abstract: Purpose: An end-to-end deep convolutional neural network (CNN) based on deep residual network (ResNet) was proposed to efficiently reconstruct reliable T2 mapping from single-shot OverLapping-Echo Detachment (OLED) planar imaging. Methods: The training dataset was obtained from simulations carried out on SPROM software developed by our group. The relationship between the original OLED image containing two echo signals and the corresponded T2 mapping was learned by ResNet training. After the ResNet was trained, it was applied to reconstruct the T2 mapping from simulation and in vivo human brain data. Results: Though the ResNet was trained entirely on simulated data, the trained network was generalized well to real human brain data. The results from simulation and in vivo human brain experiments show that the proposed method significantly outperformed the echo-detachment-based method. Reliable T2 mapping was achieved within tens of milliseconds after the network had been trained while the echo-detachment-based OLED reconstruction method took minutes. Conclusion: The proposed method will greatly facilitate real-time dynamic and quantitative MR imaging via OLED sequence, and ResNet has the potential to reconstruct images from complex MRI sequence efficiently.

Facile synthesis of MgAl2O4 with high crystallinity from KCl–MgCl2 composite molten salts

Abstract: MgAl2O4 (MA) powder has been synthesised by heating an equimolar composition of commercial Al2O3 and calcined MgO via a molten salt synthesis (MSS) method Phase compositions, microstructures, elements distributions, particle size and specific surface area of as-synthesised MA at various temperatures were investigated The synthesis reaction of MA from Al2O3 and MgO is incomplete at 1000 and 1100°C for 4 h in KCl–MgCl2 molten salts MgAl2O4 powder can be produced via the MSS method at 1200°C for 4 h, which is ∼200°C lower than that of conventional solid–solid reaction (SSR) method Fine MA particles can be formed at 1000, 1100 and 1200°C for 4 h, and most of them aggregate With the increase in reaction temperature from 1000 to 1200°C, the particle size of as-synthesised MA powder decreases and specific surface area increases The average grain size and the specific surface area of the fabricated powder at 1200°C for 4 h are 757 μm and 07566 m2 g-1, respectively Single MA crystalline phase is detected

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...