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Precambrian mafic dyke swarms in the North China Craton and their geological implications
A map of major Precambrian mafic dyke swarms and related units in the North China Craton is compiled, and the features and geological implications of these swarms are demonstrated. The Archean dyke swarms are available to portray the early crustal growth and cratonization. The middle Paleoproterozoic （2200-1850 Ma） swarms and related magmatic series could constrain the tectonic evolution： They approve that the craton was amalgamated by two sub-cratons. The late Paleoproterozoic （1800-1600 Ma）, Mesoproterozoic （1400-1200 Ma） and Neoproterozoic （1000-800 Ma） series swarms are important in paleogeographic reconstruction： they indicate that North China might have connected with some of the North European and North American cratons during Proterozoic. Dyke swarms are not only geological timescales and tectonic markers but also evolution indicators of lithospheric mantle： they imply a rejuvenation of the sub-continental lithospheric mantle of North China at 1780-1730 Ma. These swarms occurred with several rifts, including the Hengling （2200-1970 Ma）, Xuwujia （1970-1880 Ma）, Xiong＇er （1800-1600 Ma）, Yan-Liao （1730-1200 Ma）, and Xu-Huai （1000-800 Ma）. Among them, the Xuwujia rift was possibly continental arc associated; whereas the others were intra-continental. In addition, the Xiong＇er and Xu-Huai rifts were possibly triple junctions along the present southern and southeastern margins of the Craton, respectively. Different tectonic set- tings of these rifts and dyke swarms would result in diversified series of ore deposits.
Journal Article
In situ ammonium formation mediates efficient hydrogen production from natural seawater splitting
Seawater electrolysis using renewable electricity offers an attractive route to sustainable hydrogen production, but the sluggish electrode kinetics and poor durability are two major challenges. We report a molybdenum nitride (Mo
2
N) catalyst for the hydrogen evolution reaction with activity comparable to commercial platinum on carbon (Pt/C) catalyst in natural seawater. The catalyst operates more than 1000 hours of continuous testing at 100 mA cm
−2
without degradation, whereas massive precipitate (mainly magnesium hydroxide) forms on the Pt/C counterpart after 36 hours of operation at 10 mA cm
−2
. Our investigation reveals that ammonium groups generate in situ at the catalyst surface, which not only improve the connectivity of hydrogen-bond networks but also suppress the local pH increase, enabling the enhanced performances. Moreover, a zero-gap membrane flow electrolyser assembled by this catalyst exhibits a current density of 1 A cm
−2
at 1.87 V and 60
o
C in simulated seawater and runs steadily over 900 hours.
Efficient catalysts for seawater electrolysis are crucial for sustainable hydrogen production but struggle with slow kinetics and low durability. Here, the authors report a molybdenum nitride catalyst that in situ generates ammonium groups, enhancing both performance and stability in natural seawater.
Journal Article
Fashion illustration : wedding dress inspiration
\"A wedding dress is the dream dress of every woman. This book invites Peng Jing (China Top 10 Fashion Designer) as the writer to introduce the working process of wedding dress, relationship between wedding dress design and illustrations, and how to paint wedding dress illustrations from the perspective of design and painting. It includes knowledge such as painting tools and materials, body structure, texture expression and detail expression, and detailed step-by-step tutorials of illustrations and a large amount of delicate illustration works, including wedding dresses, formal dresses, Chinese wedding dresses and accessories. Through this book, readers can master the basics of wedding dress illustration easily and paint excellent wedding dress illustrations.\"-- Publisher's description.
Book
Thermally activated delayed fluorescence (TADF) organic molecules for efficient X-ray scintillation and imaging
X-ray detection, which plays an important role in medical and industrial fields, usually relies on inorganic scintillators to convert X-rays to visible photons; although several high-quantum-yield fluorescent molecules have been tested as scintillators, they are generally less efficient. High-energy radiation can ionize molecules and create secondary electrons and ions. As a result, a high fraction of triplet states is generated, which act as scintillation loss channels. Here we found that X-ray-induced triplet excitons can be exploited for emission through very rapid, thermally activated up-conversion. We report scintillators based on three thermally activated delayed fluorescence molecules with different emission bands, which showed significantly higher efficiency than conventional anthracene-based scintillators. X-ray imaging with 16.6 line pairs mm
−1
resolution was also demonstrated. These results highlight the importance of efficient and prompt harvesting of triplet excitons for efficient X-ray scintillation and radiation detection.
Triplet exciton harvesting through thermally activated delayed fluorescence is shown to be effective also under X-ray excitation, increasing the efficiency and imaging quality of X-ray detectors based on organic scintillation.
Journal Article
Immunological and inflammatory profiles in mild and severe cases of COVID-19
COVID-19 is associated with 5.1% mortality. Although the virological, epidemiological, clinical, and management outcome features of COVID-19 patients have been defined rapidly, the inflammatory and immune profiles require definition as they influence pathogenesis and clinical expression of COVID-19. Here we show lymphopenia, selective loss of CD4+ T cells, CD8+ T cells and NK cells, excessive T-cell activation and high expression of T-cell inhibitory molecules are more prominent in severe cases than in those with mild disease. CD8+ T cells in patients with severe disease express high levels of cytotoxic molecules. Histochemical studies of lung tissue from one fatality show sub-anatomical distributions of SARS-CoV-2 RNA and massive infiltration of T cells and macrophages. Thus, aberrant activation and dysregulation of CD8+ T cells occur in patients with severe COVID-19 disease, an effect that might be for pathogenesis of SARS-CoV-2 infection and indicate that immune-based targets for therapeutic interventions constitute a promising treatment for severe COVID-19 patients.
Immunophenotyping of patients with COVID-19 is ongoing, but much remains to be learned. Here the authors analyze 41 hospitalized patients with COVID-19 and show a higher degree of lymphopenia in various immune cell subsets as well as cytotoxicity and T cell inhibitory marker expression in severe cases compared with mild.
Journal Article
All this and more : a novel
\"From the critically acclaimed, bestselling author of The Cartographers and The Book of M comes an inventive new novel about a woman who wins the chance to rewrite every mistake she's ever made... and how far she'll go to find her elusive \"happily ever after.\" But there's a twist: the reader gets to decide what she does next to change her fate. Meek, play-it-safe Marsh has just turned forty-five, and her life is in shambles. Her career is stagnant, her marriage has imploded, and her teenage daughter grows more distant by the day. Marsh is convinced she's missed her chance at everything--romance, professional fulfillment, and adventure--and is desperate for a do-over. She can't believe her luck when she's selected to be the star of the global sensation All This and More, a show that uses quantum technology to allow contestants the chance to revise their pasts and change their present lives. It's Marsh's only shot to seize her dreams, and she's determined to get it right this time. But even as she rises to become a famous lawyer, gets back together with her high school sweetheart, and travels the world, she begins to worry that All This and More's promises might be too good to be true. Because while the technology is amazing, something seems a bit off... Can Marsh really make her life everything she wants it to be? And is it worth it?\"-- Provided by publisher.
Book
Dirac-source field-effect transistors as energy-efficient, high-performance electronic switches
The operating power of field-effect transistors is constrained in part by the minimum change in voltage needed to change the current output. This subthreshold swing (SS) limit is caused by hotter electrons from a thermal electron source leaking over the potential of the gate electrode. Qiu et al. show that graphene can act as a Dirac source that creates a narrower distribution of electron energies. When coupled to a carbon nanotube channel, the decrease in SS would allow the supply voltage to be decreased from 0.7 to 0.5 volts. Science , this issue p. 387 A graphene source of cold electrons lowers the subthreshold swing and supply voltage in field-effect transistors. An efficient way to reduce the power consumption of electronic devices is to lower the supply voltage, but this voltage is restricted by the thermionic limit of subthreshold swing (SS), 60 millivolts per decade, in field-effect transistors (FETs). We show that a graphene Dirac source (DS) with a much narrower electron density distribution around the Fermi level than that of conventional FETs can lower SS. A DS-FET with a carbon nanotube channel provided an average SS of 40 millivolts per decade over four decades of current at room temperature and high device current I 60 of up to 40 microamperes per micrometer at 60 millivolts per decade. When compared with state-of-the-art silicon 14-nanometer node FETs, a similar on-state current I on is realized but at a much lower supply voltage of 0.5 volts (versus 0.7 volts for silicon) and a much steeper SS below 35 millivolts per decade in the off-state.
Journal Article