Magnesium isotope geochemistry of the carbonate-silicate system in subduction zonesOA

The lighter magnesium(Mg) isotopic signatures observed in intraplate basalts are commonly thought to result from deep carbonate recycling, provided that the sharp difference in Mg isotopic composition between surface carbonates and the normal mantle is preserved during plate subduction. However, deep subduction of carbonates and silicates could potentially fractionate Mg isotopes and change their chemical compositions. Subducting silicate rocks that experience metamorphic dehydration lose a smal...     

Ionic Liquid Studies Lead to New Ways of Urea Derivative Synthesis

An environment-friendly ap-proach to producing sym-metric urea derivatives hasbeen developed by Deng Youquanand his colleagues at the Centre forGreen Chemistry and Catalysis un-der the CAS Lanzhou Institute ofChemical Physics.Urea derivatives, together withisocyanates and carbonates, are N-containing compounds. As importantchemicals, their production in theworld is enormous. For example, theoutput of isocyanates in 2001 ex-ceeded five megatons.Unfortunately, they are mainlymanufactured b…     

A Newly Established Fernery

With the financial supportfor botanical gardensfrom the Ministry ofFinance, a fern garden has recentlybeen established at the CASKunming Institute of Botany.Ferns are on the top of theevolutionary tree of spore plants.Some fern species are valued asornaments, medication and food.With a 250-square-meter exhibitiongreenhouse and a 50-square-meterbreeding room, the sanctuary hasmore than 300 typical fern speciesoriginally distributed in tropical,subtropical and temperate zones invarious ecolog…     

Space telescope set to open a new chapter in China's solar researchOA

<正>One year after China launched its first dedicated space telescope to study the Sun, the Advanced Space-based Solar Observatory(ASO-S) is now fine-tuned and ready for discoveries during the activity peak of this solar cycle. ‘ASO-S has completed its in-orbit tests, and all instruments are in stable operation. Some early results are already in the pipeline,’ said the mission’s chief scientist, Gan Weiqun, as the telescope was officially delivered to his co-workers at the Purple Mountain O...     

Deep carbon cycling during subduction revealed by coexisting diamond-methane-magnesite in peridotite

<正>Subduction is an important process for transferring materials from the surface into the deep mantle.During subduction,recycled carbon can be released from the subducting slab to the mantle wedge through various decarbonation processes.Both oxidized(CO₂/CO₃^2-) and reduced(CH₄) carbon-bearing species have been discovered in(ultra)high-pressure(HP-UHP) subduction zones worldwide [1-3].Diamond is a typical index mineral for UHP metamorphism.     

Mapping uncovered a multi-phase arc-back-arc system in the southern Beishan during the Permian

<正>The Central Asian orogenic belt(CAOB),surrounded by the Baltica and Siberia cratons to the north,and the Tarim and North China cratons to the south,records successive evolution cycles of subduction and accretion/collision from Neoproterozoic to the Paleozoic that consumed and eventually closed the Paleo-Asian Ocean[1].Tectonic models of the terminal orogenesis are contentious,with discussions ranging from the time and location of final closure of the Paleo-Asian Ocean to the regional co...     

Robotic mobile and mirror milling of large-scale complex structuresOA

<正>Large-scale complex structures,such as spacecraft cabins,aircraft composite skins and launch vehicle fuel tanks,are the core components of the equipment in aerospace,energy,shipbuilding and other fields.Their milling quality and efficiency are factors directly affecting the performance and productivity of spacecraft,aircraft and other key equipment.This kind of structure generally features large dimension,high accuracy,     

Photodegradable polar-functionalized polyethylenesOA

The degradation of plastics has attracted much attention from the global community.Polyethylenes(PEs),as the most abundant synthetic plastics,are most frequently studied.PE is non-degradable and non-polar because of the sole presence of the pure hydrocarbon components.Concurrent incorporation of both in-chain cleavable and functional groups into the PE chain is an effective pathway to overcome the non-degradable and non-polar issue;however,the method for achieving this pathway remains elusive.He...     

Testing flexible polymer solar cells in near-spaceOA

<正>Since the big success of the Vanguard1 mission,being the first solar-powered satellite,the use of solar cells in space developed very rapidly.Today,conventional solar cell technologies for space are based on silicon and GaAs modules.If significantly higher power conversion efficiencies (PCEs) are required,