NeuDATool:an Open Source Neutron Data Analysis Tools,Supporting GPU Hardware Acceleration,and across-Computer Cluster Nodes Parallel

Empirical potential structure refinement is a neutron scattering data analysis algorithm and a software package. It was developed by the disordered materials group in the British spallation neutron source (ISIS) in 1980s, and aims to construct the most-probable atomic structures of disordered materials in the field of chemical physics. It has been extensively used during the past decades, and has generated reliable results. However, it implements a shared-memory architecture with open multi-processing (OpenMP). With the extensive construction of supercomputer clusters and the widespread use of graphics processing unit (GPU) acceleration technology, it is now possible to rebuild the EPSR with these techniques in the effort to improve its calculation speed. In this study, an open source framework NeuDATool is proposed. It is programmed in the object-oriented language C++, can be paralleled across nodes within a computer cluster, and supports GPU acceleration. The performance of NeuDATool has been tested with water and amorphous silica neutron scattering data. The test shows that the software can reconstruct the correct microstructure of the samples, and the calculation speed with GPU acceleration can increase by more than 400 times, compared with CPU serial algorithm at a simulation box that has about 100 thousand atoms. NeuDATool provides another choice to implement simulation in the (neutron) diffraction community, especially for experts who are familiar with C++ programming and want to define specific algorithms for their analysis.     

Photoreduction of mercury(II) in the presence of algae, Anabaena cylindrical

The photochemical and biological reduction of Hg(II) in the presence of algae, anabaena cylindrical, was investigated under the irradiation of metal halide lamps placed in cooling trap for maintaining constant temperature by water circulation (lambda >or=365 nm, 250 W). The photoreduction rate of Hg(II) increased with increasing algae concentration. The addition of Fe(III) and humic substances into the suspensions of algae also enhanced the photoreduction of Hg(II). Alteration of pH value affected the photoreduction of Hg(II) in aqueous solution with or without the addition of algae. The concentration of dissolved gaseous mercury (DGM), the reduced product of Hg(II), increased with increasing exposure time and then gradually approached to a steady state. The influence of initial Hg(II) concentration on the photoreduction of Hg(II) with algae was studied by irradiating the suspensions of anabaena cylindrical at pH 7.0 with initial concentrations (C(0)) of Hg(II) at 50, 100, 120, 150 and 180 microg L(-1), respectively, the light-induced reduction of Hg(II) followed the apparent pseudo first-order kinetics. The initial photoreduction rate could be expressed by the equation: r(A)=0.0871+0.00129 C(0), with a correlation coefficient R=0.9994. The overall mercury mass balance study on the photo-reductive process revealed that more than 39.86% of Hg(II) from the algal suspension was reduced to volatile metallic mercury.     

Microwave-assisted one-pot synthesis of benzo[b][1,4]thiazin-3(4H)-ones via Smiles rearrangement

The synthesis of benzo[b][1,4]thiazin-3(4H)-one derivatives in a simple and efficient method from the one-pot reaction of substituted 2-chlorobenzenthiols, chloroacetyl chloride, and primary amines via Smiles rearrangement under microwave irradiation gave high yields (65-92%) of the products with short reaction time (15-20 min).     

Interfacial Evolution of Lithium Dendrites and Their Solid Electrolyte Interphase Shells of Quasi‐Solid‐State Lithium‐Metal Batteries

Unstable electrode/solid‐state electrolyte interfaces and internal lithium dendrite penetration hamper the applications of solid‐state lithium‐metal batteries (SSLMBs), and the underlying mechanisms are not well understood. Herein, in situ optical microscopy provides insights into the lithium plating/stripping processes in a gel polymer electrolyte and reveals its dynamic evolution. Spherical lithium deposits evolve into moss‐like and branch‐shaped lithium dendrites with increasing current densities. Remarkably, the on‐site‐formed solid electrolyte interphase (SEI) shell on the lithium dendrite is distinctly captured after lithium stripping. Inducing an on‐site‐formed SEI shell with an enhanced modulus to wrap the lithium precipitation densely and uniformly can regulate dendrite‐free behaviors. An in‐depth understanding of lithium dendrite evolution and its functional SEI shell will aid in the optimization of SSLMBs.     

Nanoparticle‐Assisted Alignment of Carbon Nanotubes on DNA Origami

Aligning carbon nanotubes (CNTs) is a key challenge for fabricating CNT‐based electronic devices. Herein, we report a spherical nucleic acid (SNA) mediated approach for the highly precise alignment of CNTs at prescribed sites on DNA origami. We find that the cooperative DNA hybridization occurring at the interface of SNA and DNA‐coated CNTs leads to an approximately five‐fold improvement of the positioning efficiency. By combining this with the intrinsic positioning addressability of DNA origami, CNTs can be aligned in parallel with an extremely small angular variation of within 10°. Moreover, we demonstrate that the parallel alignment of CNTs prevents incorrect logic functionality originating from stray conducting paths formed by misaligned CNTs. This SNA‐mediated method thus holds great potential for fabricating scalable CNT arrays for nanoelectronics.     

Recent Advances in the Synthesis,Surface Modifications and Applications of Core‐Shell Magnetic Mesoporous Silica Nanospheres

The hierarchically structured core‐shell magnetic mesoporous silica nanospheres (Mag‐MSNs) have attracted extensive attention, particularly in studies involving reliable preparations and diverse applications of the multifunctional nanomaterials in multi‐disciplinary fields. Intriguingly, Mag‐MSNs have been prepared with well‐designed synthesis strategies and used as adsorbent materials, biomedicines, and in proteomics and catalysis due to their excellent magnetic responsiveness, enormous specific surface area and readiness for surface modifications. Through a carefully designed surface modification of Mag‐MSNs, the performance and application prospects of the material are greatly improved. Typically, the introduction of various molecular matrices into the shell of Mag‐MSNs facilitates the combination of surface modifications and magnetic separation technology. So far, as sustainable chemistry is concerned, it is important to recover the functionalized core‐shell Mag‐MSNs after the reaction and reuse them without losing activity. In this review, the design conceptions and the construction of core‐shell Mag‐MSNs are discussed. Furthermore, various surface modification approaches of core‐shell Mag‐MSNs are summarized, and recent applications of these functionalized nanomaterials in the fields of biomedicine, catalysis, proteomics and wastewater treatment are exemplified.     

Identification of Catalytic Sites for Oxygen Reduction in Metal/Nitrogen‐Doped Carbons with Encapsulated Metal Nanoparticles

The development of metal‐N‐C materials as efficient non‐precious metal (NPM) catalysts for catalysing the oxygen reduction reaction (ORR) as alternatives to platinum is important for the practical use of proton exchange membrane fuel cells (PEMFCs). However, metal‐N‐C materials have high structural heterogeneity. As a result of their high‐temperature synthesis they often consist of metal‐N_x sites and graphene‐encapsulated metal nanoparticles. Thus it is hard to identify the active structure of metal‐N‐C catalysts. Herein, we report a low‐temperature NH₄Cl‐treatment to etch out graphene‐encapsulated nanoparticles from metal‐N‐C catalysts without destruction of co‐existing atomically dispersed metal‐N_x sites. Catalytic activity is much enhanced by this selective removal of metallic nanoparticles. Accordingly, we can confirm the spectator role of graphene‐encapsulated nanoparticles and the pivotal role of metal‐N_x sites in the metal‐N‐C materials for ORR in the acidic medium.     

Correlation between rheological behavior and structure of multi-component polymer systems

Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers, owing to its sensitivity to the structure change of hetero- geneous systems. In this article, recent progress in the studies on the morphology/structure and rheological properties of heterogeneous systems is summarized, mainly reporting the findings of the authors and their collaborators, involving the correlation between the morphology and viscoelastic relaxation of LCST-type polymer blends, the microstructure and linear/nonlinear viscoelastic behavior of block copolymers, time scaling of shear-induced crystallization and rheological response of poly- olefins, and the relationship between the structure/properties and rheological behavior of filled polymer blends. It is suggested that a thorough understanding of the characteristic rheological response to the morphology/structure evolution of multiphase/multi-component polymers facilitates researchers’ op- timizing the morphology/structure and ultimate mechanical properties of polymer materials.     

Syntheses,structures and luminescent properties of four d-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand

Four d¹⁰-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand (Htpim), {[Zn₂(Htpim)₄Cl₄] · 8H₂O}_n (1), {[Cd(tpim)₂(H₂O)₂] · 4CH₃OH}_n (2), {[Cu₂(Htpim)(PPh₃)₂I₂] · CH₃CN}_n (3) and {[Ag(Htpim)](NO₃) · CH₂Cl₂}_n (4), have been synthesized and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. Both complexes 1 and 2 show one dimensional ribbon-like structures. Via intermolecular hydrogen bonds, a 2D supramolecular network and 3D framework are formed for 1 and 2, respectively. Complex 3 shows a 1D zigzag chain with a CuI₂Cu rhomboid dimer. Complex 4 shows a 1D ladder-like polymer with two different metallacycles. The luminescent properties of all the complexes have been studied in the solid state.