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Stainless-steel bipolar plates (BPPs) are of great significance in low-cost, easily processable, lightweight proton exchange membrane fuel cells (PEMFCs) despite the challenge presented by corrosion in protective coatings. Localized corrosion along the grain boundaries in a crystal film is common, but few preventive measures have been developed so far. Thus, we propose a novel strategy using a tantalum (Ta) and carbon (C) co-modification to improve the chemical stability of titanium carbide (TiC)-based coatings (Cr/Ta/TiC/C). During the film growth, the subjacent Ta atoms were thermally diffused throughout the columnar structure of TiC and reacted with the C layer. The reaction product, i.e., TaC, acted as a chemical passivator to the grain boundary. Combined with the C capping layer, these functional layers synergistically suppressed any localized corrosion. Therefore, corrosion current densities within the United States Department of Energy’s technical recommendations were achieved in both potentiostatic and potentiodynamic polarization. Meanwhile, by controlling the Ta metal dispersion, the interfacial contact resistance between the multilayer structure and the carbon paper can be reduced to 7.1 mΩ·cm−2 at a compaction force of 140 N·cm−2. The substantial improvement in the corrosion resistance and conductivity of BPP places our work among the most efficient anticorrosion systems in PEMFC applications reported so far.

Novel polyaniline-titanium nitride (PANI-TiN) nanocomposites were synthesized by one step chemical oxidation polymerization at a low temperature and PANI-TiN/epoxy coatings with enhanced corrosion resistance were obtained based on the synergistic effect of TiN nanoparticles and PANI nanorods. PANI-TiN nanocomposites and resultant epoxy coatings were characterized by Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS). Their anticorrosion performance in a 3.5 wt.% NaCl aqueous solution was investigated by the electrochemical impedance spectroscopy (EIS) and polarization curves. The results indicated that the corrosion resistance of PANI/epoxy coatings can be highly enhanced by introducing TiN nanoparticles to the PANI nanorods and the PANI-TiN/epoxy composite coating with 0.4 wt.% TiN (mass ratio to epoxy) exhibited the best corrosion protective performance, whose corrosion potential (Ecorr = −0.338 V) was positively shifted by 0.235 V compared with pure epoxy matrix (Ecorr = −0.573 V), and the corrosion current density was reduced by two orders of magnitude. The chemical structure of the rust layer and the anticorrosion mechanism were studied via X-ray diffraction analysis (XRD) and XPS. TiN nanoparticles showed a remarkably inhibiting effect on the agglomeration of PANI nanorods in epoxy coating. The corrosion resistance was attributed to the mixed mechanism of “passivation effect” of highly dispersed PANI and “labyrinth effect” of TiN nanoparticles.

Long-term cycling stability is a main issue for the application of manganese-based electrodes in pseudocapacitors. Herein, we demonstrate a facile approach to enhance the cycling stability of birnessite electrodes by pre-adding slight Mn2+ into the aqueous electrolyte. The cycling performance of the electrode and the morphology of birnessite change with Mn2+ concentration, which are ascribed to the electrochemical oxidation of Mn2+ or the reduction of birnessite during the charge/discharge cycling process. By controlling a low concentration of Mn2+, the birnessite electrode exhibits enhanced capacitance and cycling stability, while a hierarchical nanosheets assembled nanowall array architecture is achieved after the prolonged cycling. The resulting electrode delivers a superior rate capability (60% retention at 20 A g−1) and a high cycling stability (93% retention after 10000 cycles). This work opens up a new strategy for the development of manganese-based electrodes with high rate performance and long-term cycling stability.

It has not been considered in the reported literatures that the current or the cyclic number of galvanostatic charge-discharge process controls the morphology growth of manganese oxide materials. Here, standing birnessite nanosheets assembled porous honeycomb architecture is in situ formed on Ni foam by electrochemical oxidation of hydrothermally synthesized Mn3O4 nanospheres electrodes via a electrochemical cycling technique. The birnessite morphology much depends on the conditions of the electrochemical cycling. By tuning the current and cycle number, Mn3O4 nanospheres are converted to birnessite with optimal morphology, while a high pseudocapacitive performance is achieved. The optimized birnessite electrodes exhibit a high level of specific capacitance (377 F g−1 at 1 A g−1), a superior rate capability (227 F g−1 at 30 A g−1) and a good cycling stability (75% retention after 4000 cycles). This work provides useful strategies for developing high-performance manganese oxide electrodes.

The high resolution image reconstruction takes an important place in the solar physics research, but the solar high resolution observation has been hindered severely for a long time due to huge observation data volume, slow reconstruction speed and other factors. In order to treat the huge volume of quasi real-time solar observation data and cope with the computing burden of the same magnitude for high resolution reconstruction of solar image, a number of advanced ground-based solar telescopes at home and abroad have adopted the speckle masking, a method of reconstruction algorithm that can be parallely realized, to reconstruct the high resolution image. Good treatment results are obtained from this method. However, it is still hard to meet the demand for solar observation data treatment at the current efficiency, since the volume of solar telescope observation data is increasing. This paper is directed at the demands of China′s new solar telescopes such as the NVST (The 1 m New Vacuum Solar Telescope) and ONSET (Optical and Near-Infrared Solar Eruption Tracer). By analyzing the computing time of each module with the Triple-Spectral method through actual measurement, the paper reaches a conclusion that the data exchange performance is a key bottleneck affecting the reconstruction effect. On this basis, the paper puts forward a universal method of global-shared low-exchange parallel high resolution image reconstruction. This method takes the Triple-Spectral as the core algorithm for image reconstruction and uses the message passing interface (MPI) and shared memory mechanism, allowing the reconstruction computing process to read and write the data in the shared memory at high speed after algorithm optimization. The shared memory, which is created for storage of image data and image reconstruction results respectively according to the size of the image, will be subsequently mapped into each process, giving access to read the processing data and store the reconstruction results independently. While computing the image reconstruction, each child process will not apply the MPI communication to obtain the sub-block image data. Instead, it will read the associated data from the shared memory according to the sub-block image numbering. After the sub-block image reconstruction is done, each child process will store the reconstruction results directly into the shared memory according to the sub-block image numbering, instead of sending the results to the host process via MPI communication. In this way the communication between processes is reduced, the comunication time saved and the data exchange efficiency improved. The experiment results show that on one 16-core PC server, it takes only about 12.4 s for reconstructing the 100-frame ONSET 1660×1660 pixel image and 5.6 s for the 100-frame NVST 1024×1024 pixel image under this method. Good efficiency is achieved in the reconstruction of solar telescope data for ONSET and NVST with different apertures, proving that this method has certain efficiency and universality. The parallel combination of the Triple-Spectral and K-T has greatly reduced the communication process and data exchange in the course of image reconstruction, saved the communication time and improved the reconstruction efficiency. To be further mentioned, the achievement of good efficiency on one server would bring the method into flexible application and save the equipment cost substantially. With the aid of the research outcome of the paper, it is expected to tackle the puzzles remained in the high resolution reconstruction of NVST and ONSET, and bring down the data storage burden. Its fulfillment of real-time high resolution reconstruction has laid a solid foundation for the follow-up researches.

Core-shell ZnO/oxygen-doped g-C 3 N 4 nanocomposite was prepared via hydrothermal method with the addition of hydrogen peroxide (H 2 O 2 ) and its visible light photocatalytic performance was investigated. In the process of hydrothermal reaction, g-C 3 N 4 nanosheets were oxidized by hydrogen peroxide and then dehydration reaction occurred between C-OH groups to form the C-O-C groups, resulting in a relatively stable oxygen doped g-C 3 N 4 nanosheets wrapped on the surface of ZnO nanoparticles. The photocatalytic performance of ZnO/oxygen-doped g-C 3 N 4 sample showed significant photocatalytic activity, higher than ZnO, g-C 3 N 4 nanosheets and ZnO/g-C 3 N 4 samples. The PL spectra indicated that the stable core-shell heterojunction of ZnO/oxygen-doped g-C 3 N 4 composite could block the recombination rate of electron−hole pairs effectively and remarkably enhanced photocatalytic activity.

In this work, the CMK-3 is successfully prepared with SBA-15 as the template and first annealed to 2000 &deg, C to improve thermal conductivity. The annealed CMK-3 has a thermal conductivity of 6.981 W m&minus, 1 K&minus, 1 higher than un-annealed CMK-3. The annealed CMK-3 is used to encapsulate the RT44HC, and RT44HC/annealed CMK-3 has 10-fold of thermal conductivity and enhanced thermal stability than RT44HC. The RT44HC/annealed CMK-3 has a large melting enthalpy of 177.8 J g&minus, 1 and good thermal stability. The RT44HC/annealed CMK-3 has optical absorptive coefficient of visible range of solar spectrum, which identify seven-fold higher than RT44HC. The RT44HC/annealed CMK-3 has great photo-thermal performance, and the photo-driven energy charging and discharging rate of RT44HC/annealed CMK-3 is almost 30-fold larger than the RT44HC. The results show that the annealed CMK-3 is a great mesoporous carbon nanomaterial for phase change materials and the annealed CMK-3 based phase change material has great potential in solar thermal utilizations such as solar water heating system and solar heating building systems.

A novel strategy to construct polybenzimidazole linked crosslinking networks (PLCNs) is proposed. A benzoxazine-ended PBI oligomer (BPBI) is prepared, which can react with PBI from the ended benzoxazine groups to form PLCNs. It is proved that the ring-opening reaction of benzoxazine is activated by benzimidazoles mainly from the N–H site in a BIm-rich background and forms phenoxy-type, phenolic-type and crosslinking structures successively under heat. Crosslinked by 15 wt% of BPBI, properties of PBI are remarkably improved with 74% enhancement on tensile strength, 78 °C improvement on sub-Tg transition temperature and 49% increasement on acid uptake. Besides, PBI-Ben(15)-356%PA exhibits a high proton conductivity of 0.122 S cm−1 with a low activation energy of 17.2 kJ mol−1 under 180 °C. As BPBI is thermally stable at room temperature and can crosslink commercial PBI simply by heat, it exhibits promising commercial prospects in the application of polymer electrolyte fuel cells.

The Mingantu Ultrawide Spectral Radioheliograph (MUSER) is a synthetic-aperture radio interferometer built in Ming'antu, Inner Mongolia, China. As a solar-dedicated interferometric array, the MUSER can produce high-quality radio images in a frequency range of 400 MHz-15 GHz with high temporal, spatial, and spectral resolution. Implementing of the data processing system for the MUSER is a major challenge to performing high-cadence imaging in wideband and obtaining more than two orders of higher multiple frequencies. There is an urgent need to build a pipeline for processing the massive amount of MUSER data generated each day. In this article, we present a high-performance distributed data processing pipeline (DDPP) built on the OpenCluster infrastructure for processing MUSER observational data, including data storage, preprocessing, image reconstruction, deconvolution, archiving, and real-time monitoring. We comprehensively elaborate the system architecture of the pipeline and the implementation of each subsystem. The DDPP is automatic, robust, scalable, and manageable. The processing performance under a parallel CPU/GPU hybrid system meets the requirements of MUSER data processing.

As a dedicated synthetic aperture radio interferometer in China, the MingantU SpEctral Radioheliograph (MUSER), initially known as the Chinese Spectral RadioHeliograph (CSRH), has entered the stage of routine observation. More than 23 million data records per day need to be effectively managed to provide high-performance data query and retrieval for scientific data reduction. In light of these massive amounts of data generated by the MUSER, in this paper, a novel data management technique called the negative database (ND) is proposed and used to implement a data management system for the MUSER. Based on the key-value database, the ND technique makes complete utilization of the complement set of observational data to derive the requisite information. Experimental results showed that the proposed ND can significantly reduce storage volume in comparison with a relational database management system (RDBMS). Even when considering the time needed to derive records that were absent, its overall performance, including querying and deriving the data of the ND, is comparable with that of a relational database management system (RDBMS). The ND technique effectively solves the problem of massive data storage for the MUSER and is a valuable reference for the massive data management required in next-generation telescopes.

A phase transition from spinel Mn3O4 to layered birnessite has been reported through electrochemically induced activation in aqueous electrolyte for high performance supercapacitor, battery and water splitting applications. Here, Li2SO4, MgSO4 and K2SO4 aqueous electrolytes were used for the activation of Mn3O4 electrode to investigate the effect of electrolyte cation on the electrochemical activation. The Mn3O4 electrode exhibited different activated results in the three electrolytes, including the efficiency of phase transition, morphology of resulting birnessite and capacitive performance of the activated electrode. The cations affect the proceeding of H+ insertion or the peeling-off of birnessite nanosheets during the phase transition process, resulting in the formation of nanosheet materials with different lateral dimensions. Effect of electrolyte cation on the electrochemical behavior of nanosheets electrode is further investigated. The nanosheets electrode activated in K2SO4 exhibits capable capacitive behavior with reasonable specific capacitance and cycling stability. Understanding how different cations affect the phase transition of Mn3O4 together with its capacitive performance will conduce to the development of manganese oxide electrode systems with high performance.

In this work, a mixture of polyethylene and ethylene-propylene-diene copolymer is used as a base polymer to prepare the paraffin/expanded graphite composite by extrusion technology. The as-prepared phase change material has tensile strength of 8.1 MPa, bending strength of 14.7 MPa, thermal conductivity of 2.08 W m -1 K -1 and melting enthalpy of 139 J g -1 . We found that the polyethylene has an advantage of increasing the compactness of phase change material and the ethylene-propylene-diene copolymer could improve the compatibility of phase change material. The polyethylene and ethylene-propylene-diene copolymer could confine the phase change materials in the narrow space to improve the mechanical property, and the optimized ratio of polyethylene and ethylene-propylene-diene copolymer could improve the dispersity of expanded graphite to increase thermal conductivity. The optimized phase change material shows great photo-thermal performance with storage capacity of 1700J in 270s, which takes 8.3% of time than pure paraffin. This work provides a strategy to prepare a robust phase change material with good mechanical and thermal properties and photo-thermal performance.

The volume of data generated by modern astronomical telescopes is extremely large and rapidly growing. However, current high-performance data processing architectures/frameworks are not well suited for astronomers because of their limitations and programming difficulties. In this paper, we therefore present OpenCluster, an open-source distributed computing framework to support rapidly developing high-performance processing pipelines of astronomical big data. We first detail the OpenCluster design principles and implementations and present the APIs facilitated by the framework. We then demonstrate a case in which OpenCluster is used to resolve complex data processing problems for developing a pipeline for the Mingantu Ultrawide Spectral Radioheliograph. Finally, we present our OpenCluster performance evaluation. Overall, OpenCluster provides not only high fault tolerance and simple programming interfaces, but also a flexible means of scaling up the number of interacting entities. OpenCluster thereby provides an easily integrated distributed computing framework for quickly developing a high-performance data processing system of astronomical telescopes and for significantly reducing software development expenses.

Interleukin-12 (IL-12) serves an important role in immune responses and antitumor activity. The study of the association between autophagy and cancer cells remains controversial. The present study aimed to investigate the effect of IL‑12 on autophagy in the human breast cancer cell lines MDA‑MB‑231 and MCF‑7, and the possible molecular mechanism. Breast cancer cells were treated with different concentrations of recombinant IL‑12. The expression of the autophagy-associated protein microtubule‑associated protein light chain 3 (LC3) was determined using western blot analysis, fluorescein isothiocyanate‑labeled LC3 was detected using fluorescence microscopy and autophagosomes were examined using transmission electron microscopy. Alterations in the phosphatidylinositol 3‑kinase/Rac‑α serine/threonine protein kinase (PI3K/Akt) and 5'‑AMP‑activated protein kinase subunit β‑1 (AMPK) pathways, in addition to pathway‑associated proteins, were detected using western blotting, following treatment with IL‑12 and pretreatment with the PI3K/Akt activator insulin‑like growth factor or the AMPK inhibitor compound C. It was observed that IL‑12 was able to upregulate the expression of the autophagy‑associated protein LC3 in a concentration‑ and time‑dependent manner, and induce the formation of autophagosomes in the two cell lines, and that the above effects involved the inhibition of the PI3K/Akt signaling pathway and the activation of the AMPK signaling pathway.

As a dedicated solar radio interferometer, the MingantU SpEctral RadioHeliograph (MUSER) generates massive observational data in the frequency range of 400 MHz -- 15 GHz. High-performance imaging forms a significantly important aspect of MUSER's massive data processing requirements. In this study, we implement a practical high-performance imaging pipeline for MUSER data processing. At first, the specifications of the MUSER are introduced and its imaging requirements are analyzed. Referring to the most commonly used radio astronomy software such as CASA and MIRIAD, we then implement a high-performance imaging pipeline based on the Graphics Processing Unit (GPU) technology with respect to the current operational status of the MUSER. A series of critical algorithms and their pseudo codes, i.e., detection of the solar disk and sky brightness, automatic centering of the solar disk and estimation of the number of iterations for clean algorithms, are proposed in detail. The preliminary experimental results indicate that the proposed imaging approach significantly increases the processing performance of MUSER and generates images with high-quality, which can meet the requirements of the MUSER data processing.

FCM is populated in image segmentation for its simplicity and easily realization. The classic FCM segmentation used only the gray value for segmentation, and is liable to stuck at local values, and the result is relied on cluster center of initial selection. In this paper, we present a Genetic fuzzy c-means (GFCMS) algorithm that incorporates spatial information for segmentation. The first improvement is to use the spatial information of pixel in FCM algorithm. The second improvement is to use the genetic algorithm for searching the global optimum. The results of the experiment validates that the algorithm has better adaptability and gets the correct global optimum.

In this paper, we present a novel algorithm for fuzzy segmentation of infrared image data using fuzzy clustering. A conventional FCM assigns the data into group, where the data is nearest to the center of group. Although FCM is populated in image segmentation, it still has the following disadvantages: (1) a conventional FCM algorithm does not consider spatial information for clustering. (2) The algorithm is sensitive to noise. In this paper we present a fuzzy-means algorithm that incorporates spatial information and the prior probability of a pixel neighborhood into the membership function for clustering. The modified FCM has a great improvement for noisy image and infrared image segmentation.

This study is to investigate a new representation of a partition of an image domain into a number of regions using a level set method derived from a statistical framework. The proposed model is composed of evolving simple closed planar curves by a region-based force determined by maximizing the posterior image densities over all possible partitions of the image plane containing three terms: a Bayesian term based on the prior probability, a regularity term adopted to avoid the generation of excessively irregular and small segmented regions, and a term based on a region merging prior related to region area, which is applied to allow the number of regions to vary automatically during curve evolution and therefore can optimize the objective functional implicitly with respect to the number of regions. This formulation leads to a system of coupled curve evolution equations, which is easily amenable to a level set implementation, and an unambiguous segmentation because the evolving regions form a partition of the image domain at all times during curve evolution. Given these advantages, the proposed method can get good performance and experiments show promising segmentation results on both synthetic and real images.