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.

Influence of Different CH4/N2 Ratios on Structural and Mechanical Properties of a-CNx:H Film Synthesized Using Plasma Focus

Abstract: Carbon nitride films were synthesized by operating the dense plasma focus device with different CH4/N2 admixture gas ratios and fixed 20 focus shots. The pressure and axial distance from anode tip were kept constant at 3 mbar and 8 cm respectively. Raman and X-ray photoelectron spectroscopy (XPS) techniques were used to observe the effect of CH4/N2 ratio on carbon nitride bonding. The XPS analysis showed that the terminating group C≡N is more dominant for the films synthesized using higher concentration of nitrogen which gives softer films. Field emission scanning electron microscopy results showed that the deposited films consist of nanoparticles and their agglomerates. The size of agglomerates increases with decreasing concentration of nitrogen in CH4/N2 admixture gas. Nanoindentation results showed the increase in hardness and elastic modulus values of films with decreasing concentration of nitrogen in CH4/N2 admixture gas. The hardness and elastic modulus values were found to be dependent on sp3 content in the film as well as the C≡N. The hardness and elastic modulus values of 10.7 and 229.8 GPa respectively were achieved for the films deposited with fixed 20 focus deposition shots and using CH4/N2 admixture gas ratio of 7:3.

Dynamic Alterations in Spontaneous Brain Activity in Mothers: A Resting-State Functional Magnetic Resonance Imaging Study

Abstract: Becoming a mother is one of the most monumental experiences in a woman’s lifetime. Women typically bear the primary caregiving responsibility for their infants, and they undergo numerous changes both mentally and physically, including behavioral, emotional, and hormonal changes, during the postpartum period. Studies have indicated that hormonal, experiential, and temporal factors significantly regulate emotional and cognitive brain functions during the postpartum period [1]. The determination of the neural basis of a maternal brain is critically important for understanding mother-infant attachments and thus perpetuating the human species. Until recently, limited investigations of the neuroanatomical and functional status of mothers have contributed to understanding the processing of maternal behaviors. Previous studies using magnetic resonance imaging (MRI) technology have indicated that the brains of mothers undergo both structural and functional changes during the postpartum period. Structural MRI has indicated that brain structures in mothers show dynamic plasticity, including alterations in grey matter volume. These longitudinal voxel-based morphometry studies have confirmed that pregnancy induces substantial structural changes, such as alterations in the grey matter volume in regions associated with social cognition and maternal motivation and behavior [2]. Longitudinal task-related functional MRI (fMRI) studies have shown that emotional reactivity is increased 4–6 weeks postpartum in healthy women [3]. Activity in prefrontal areas during response inhibition tasks decreases over time during the postpartum period [4]. The results of these studies indicate that the neural mechanisms of cognitive and emotional processing likely vary in healthy mothers, which suggests that structurally and functionally important adaptations occur during the postpartum period. Researchers have found that the risk of postpartum mental disorders, such as depression, anxiety, and mood swings, is increased for several months after delivery among primiparous mothers [5]. A resting-state fMRI (rsfMRI) study investigated postpartum depression and discovered that depressed mothers show significant increases in regional homogeneity (ReHo) in the posterior cingulate gyrus, parietal lobe, and frontal lobe [6]. These studies revealed that the resting-state activity of the default mode network might be associated with impaired empathic and self-other relational processing in women with postpartum depression [7]. However, most published studies have focused on postpartum depression, while few have explored the patterns of spontaneous brain activity in healthy mothers. Recently, a study of postpartum women without depression indicated that spontaneous neural Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12264-019-00392-7) contains supplementary material, which is available to authorized users.

Microencapsulated phase change materials composited Al 2 O 3 –SiO 2 aerogel and the thermal regulation properties

Abstract: Phase change materials (PCMs) are effective energy storage application, which can be combined with aerogels to improve heat conversion rate in building insulation materials. A low-cost microencapsulated PCMs (MEPCM) composited Al2O3–SiO2 aerogels (MEPCM/ASA) have been successfully prepared by in situ sol–gel method following by ambient pressure drying (APD). The aerogels and the phase change microcapsules were well bonded without destroying the aerogels network structure. The morphology, microstructure, thermal conductivity, energy storage efficiency, and thermal stability of the MEPCM/ASA composite were comprehensively investigated. The experimental results showed that the composite revealed small shrinkage (4.1 wt%), high specific surface area (380.22 m2/g), and low thermal conductivity (0.0507 W/(m K)) at room temperature. The latent heat of the composites containing 50 wt% MEPCM reached 28.91 J/g around 26.7 °C. The MEPCM/ASA possessed good phase change behavior, low undercooling, and excellent thermal cycling stability. It was anticipated to provide a new path to achieve simultaneous enhancement of thermal insulation and thermal storage, and the application in building materials were of great importance for energy saving.

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...