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  • Laser-Induced Creation of Antiferromagnetic 180-Degree Domains in NiO/Pt Bilayers

    Meer, Hendrik; Wust, Stephan; Schmitt, Christin; Herrgen, Paul; Fuhrmann, Felix; Hirtle, Steffen; Bednarz, Beatrice; Rajan, Adithya; Ramos, Rafael; Niño, Miguel Angel; Foerster, Michael; Kronast, Florian; Kleibert, Armin; Rethfeld, Baerbel; Saitoh, Eiji; Stadtmüller, Benjamin; Aeschlimann, Martin; Kläui, Mathias (Advanced Functional Materials, Wiley, 2023-03-18) [Article]
    The antiferromagnetic order in heterostructures of NiO/Pt thin films can be modified by optical pulses. After the irradiation with laser light, the optically induced creation of antiferromagnetic domains can be observed by imaging the created domain structure utilizing the X-ray magnetic linear dichroism effect. The effect of different laser polarizations on the domain formation can be studied and used to identify a polarization-independent creation of 180° domain walls and domains with 180° different Néel vector orientation. By varying the irradiation parameters, the switching mechanism can be determined to be thermally induced. This study demonstrates experimentally the possibility to optically create antiferromagnetic domains, an important step towards future functionalization of all optical switching mechanisms in antiferromagnets.
  • Sintering-free catalytic ammonia cracking by vertically standing 2D porous framework supported Ru nanocatalysts

    Kim, Seok-Jin; Nguyen, Thien Si; Mahmood, Javeed; Yavuz, Cafer T. (Chemical Engineering Journal, Elsevier BV, 2023-03-18) [Article]
    Catalytic ammonia decomposition enables ammonia to be a hydrogen gas carrier for a carbon-free fuel economy. The challenge is to obtain high conversion yields and rates at low temperatures for a prolonged time. A promising approach is to engineer a catalyst support to minimize deleterious effects like sintering. Here, we compared a conventional 2D planar porous framework support with a vertically standing 2D structure to ascertain the effects of support geometry on the catalytic performance. The catalysts were made by loading ruthenium (Ru) nanoparticles onto the structures, and the catalytic activities were monitored by varying the ammonia (NH3) feeding rate and reaction temperature. Unlike the planar version, the vertically standing 2D support prevented nanoparticle aggregation, retained the original nanoparticle size, and showed an excellent hydrogen production rate (95.17 mmol gRu-1min-1) at a high flow rate of 32,000 ml gcat-1h-1 at a temperature of 450 ℃.
  • A universal framework for single-cell multi-omics data integration with graph convolutional networks

    Gao, Hongli; Zhang, Bin; Liu, Long; Li, Shan; Gao, Xin; Yu, Bin (Briefings in bioinformatics, Oxford University Press (OUP), 2023-03-17) [Article]
    Single-cell omics data are growing at an unprecedented rate, whereas effective integration of them remains challenging due to different sequencing methods, quality, and expression pattern of each omics data. In this study, we propose a universal framework for the integration of single-cell multi-omics data based on graph convolutional network (GCN-SC). Among the multiple single-cell data, GCN-SC usually selects one data with the largest number of cells as the reference and the rest as the query dataset. It utilizes mutual nearest neighbor algorithm to identify cell-pairs, which provide connections between cells both within and across the reference and query datasets. A GCN algorithm further takes the mixed graph constructed from these cell-pairs to adjust count matrices from the query datasets. Finally, dimension reduction is performed by using non-negative matrix factorization before visualization. By applying GCN-SC on six datasets, we show that GCN-SC can effectively integrate sequencing data from multiple single-cell sequencing technologies, species or different omics, which outperforms the state-of-the-art methods, including Seurat, LIGER, GLUER and Pamona.
  • Customizable Graphite-on-Paper based Keypads: Toward Disposable and Recyclable Wireless Human-Machine Interfaces

    Zulfiqar, Muhammad Hamza; Hassan, Mahmood Ul; Maqbool, Khawaja Qasim; Zubair, Muhammad; Mehmood, Muhammad Qasim; Riaz, K.; Massoud, Yehia Mahmoud (IEEE Journal on Flexible Electronics, Institute of Electrical and Electronics Engineers (IEEE), 2023-03-17) [Article]
    There is a rapid increase in the use of affordable electronic devices and human-machine interfaces (HMIs) with short serviceable life in almost every aspect of our lives. It’s estimated that the Waste Electrical and Electronic Equipment (WEEE) and e-waste generated in year 2021 was 57.5 million metric tons (Mt) and it is expected that the production of e-waste will increase to 110 Mt by the end of 2050. To mitigate these wastes, green HMIs are required which can be customized for multiple applications and can be recycled or disposed of with minimal environmental impact. This work presents customizable graphite-on-paper (GOP) based keypad consists of interdigitated capacitive (IDC) touch sensors is demonstrated as HMIs to interact with different electronic and media applications wirelessly. The GOP keypads are fabricated through facile and green fabrication process by direct writing of graphite on flexible paper substrate. The GOP keypads can be fabricated in a home setting as the required materials are readily available, i.e., paper, pencils, Arduino. The GOP keypads can be easily disposed of or recycled at the end of its life or requirement due to the employment of biodegradable materials like paper and graphite. The IDC touch sensors are optimized by analyzing the number of electrode fingers, finger’s width, finger’s overlap length and spacing between the electrode fingers. The same GOP keypad is customized to interact with different electronic and media applications wirelessly i.e., laptop cursor navigation, calculator app on mobile, numeric keypad etc. The customizable GOP keypads have potential to be used as green wireless HMIs to enforce a circular economy by mitigating electronic and plastic waste, which leads to the vision of a sustainable and green world.
  • An overlooked soil carbon pool in vegetated coastal ecosystems: National-scale assessment of soil organic carbon stocks in coastal shelter forests of China.

    Li, Yuan; Fu, Chuancheng; Wang, Weiqi; Zeng, Lin; Tu, Chen; Luo, Yongming (The Science of the total environment, Elsevier BV, 2023-03-17) [Article]
    Protection and restoration of vegetated coastal ecosystems provide opportunities to mitigate climate change. Coastal shelter forests as one of vegetated coastal ecosystems play vital role on sandy coasts protection, but less attention is paid on their soil organic carbon (OC) sequestration potential. Here, we provide the first national-scale assessment of the soil OC stocks, fractions, sources and accumulation rates from 48 sites of shelter forests and 74 sites of sandy beaches across 22° of latitude in China. We find that, compared with sandy beaches, shelter forest plantation achieves an average soil desalination rate of 92.0 % and reduces the soil pH by 1.3 units. The improved soil quality can facilitate OC sequestration leading to an increase of soil OC stock of 11.8 (0.60–64.2) MgC ha−1 in shelter forests. Particulate OC (POC) is a dominant OC fraction in both sandy beaches and shelter forests, but most sites are >80 % in shelter forests. The low δ13C values and higher C:N ratios, which are more regulated by climate and tree species, together with high POC proportions suggest a substantial contribution of plant-derived OC. Bayesian mixing model indicates that 71.8 (33.5–91.6)% of the soil OC is derived from local plant biomass. We estimate that soil OC stocks in Chinese shelter forests are 20.5 (7.44–79.7) MgC ha−1 and 4.53 ± 0.71 TgC in the top meter, with an accumulation rate of 45.0 (6.90 to 194.1) gC m−2 year−1 and 99.5 ± 44.9 GgC year−1. According to coastal shelter forest afforestation plan, additional 1.72 ± 0.27 TgC with a rate of 37.9 ± 17.1 GgC year−1 can be sequestrated in the future. Our findings suggest that construction of coastal shelter forests can be an effective solution to sequester more soil carbon in coastal ecosystems.

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