Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mecha...Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mechanism of Ti O_(2)and Ti N inclusions in molten Ca O–Si O_(2)–B_(2)O_(3)-based fluorine-free mold flux were explored by in situ single hot thermocouple technology combined with X-ray photoelectron spectroscopy.The results showed that Ti O_(2) inclusions are effectively dissolved by the molten slag within 76 s, during which the original octahedral [Ti O_(6)]^(8-)structures are destroyed and convert to the networker tetrahedral [Ti O_(4)]^(4-)structures. However, the dissolution rate is much lower for Ti N inclusions than for Ti O_(2)inclusions. This can be attributed to the fact that the Ti N particles need to be oxidized and then dissolved in the molten slag to form tetrahedral [Ti O4]4-and octahedral [Ti O_(6)]^(8-)structures during the Ti N inclusion dissolution process, which is accompanied by the generation of a large amount of N_(2)gas. Moreover, Ca Ti O_(3)crystals tend to nucleate and grow on bubble surfaces with sufficient octahedral [Ti O_(6)]^(8-)structures and Ca^(2+)ions, eventually resulting in the molten slag being in a solid–liquid mixed state.展开更多
The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of South China. Here, we present the detailed geochronological, geochemical and petrological analyses fo...The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of South China. Here, we present the detailed geochronological, geochemical and petrological analyses for the Jinlongyan(JLY) granite in northwest Fujian Province, southeast China. LA–ICP–MS zircon U–Pb dating yielded a weighted average ^(206)Pb/^(238)U age of 224.1 ±3.3 Ma. The granite is mainly comprised of K-feldspar,plagioclase, quartz, biotite and minor amphibole. It is characterized by enrichments in Rb, Th, REEs(total REE = 295.1–694.3 ppm), and HFSEs(e.g., Zr = 289–520 ppm, Hf = 9.3–15.0 ppm, Y = 36.2–68.2 ppm) but depletions in Ba, Sr, Eu and Ti. The granite is metaluminous to weakly peraluminous and show a clear A-type granite geochemical signature with high SiO_2(70.89 wt%–75.76 wt%), total alkalis(Na_2O + K_2O = 7.51 wt%–8.72 wt%), Ga/Al ratios(10000 Ga/Al = 2.72–3.43). Insitu zircon Hf isotope analysis shows their eHf(t) values ranging from-7.2 to-3.2, with Mesoproterozoic T2DM ages(1308–1525 Ma). Whole-rock Nd isotope data show their eNd(t) values in the range of-9.5 to-9.1 and yield paleoproterozoic TDMages(1606–1985 Ma). These characteristics indicate that the JLY A-type granite magma was formed by the partial melting of Meso-Paleoproterozoic crust rocks in the Cathaysia Block. Our study of the JLY A-type granite, together with other Triassic A-type granitesin South China, defines an extensional environment in the late Triassic which probably was caused by the collision of the South China Block with Indochina Block.展开更多
Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biol...Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biological interfaces.While electronic skin continues to achieve higher sensitivity and faster response,its ultimate performance is fundamentally limited by the nature of low-frequency AC currents.Herein,highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers(MNFs)in thin layers of polydimethylsiloxane(PDMS).Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli,the skin-like optical sensors show ultrahigh sensitivity(1870 k·Pa^-1),low detection limit(7 mPa)and fast response(10μs)for pressure sensing,significantly exceeding the performance metrics of state-of-the-art electronic skins.Electromagnetic interference(EMI)-free detection of high-frequency vibrations,wrist pulse and human voice are realized.Moreover,a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated.These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.展开更多
A novel type of mid-IR microresonator,the chalcogenide glass(ChG)microfiber knot resonator(MKR),is demonstrated,showing easy fabrication,fiber-compatible features,resonance tunability,and high robustness.ChG micro fib...A novel type of mid-IR microresonator,the chalcogenide glass(ChG)microfiber knot resonator(MKR),is demonstrated,showing easy fabrication,fiber-compatible features,resonance tunability,and high robustness.ChG micro fibers with typical diameters around 3μm are taper-drawn from As2S3 glass fibers and assembled into MKRs in liquid without surface damage.The measured Q factor of a typical 824μm diameter ChG MKR is about 2.84×104 at the wavelength of 4469.14 nm.The free spectral range(FSR)of the MKR can be tuned from2.0 nm(28.4 GHz)to 9.6 nm(135.9 GHz)by tightening the knot structure in liquid.Benefitting from the high thermal expansion coefficient of As2S3 glass,the MKR exhibits a thermal tuning rate of 110 pm·℃^-1 at the resonance peak.When embedded in polymethyl methacrylate(PMMA)film,a 551μm diameter MKR retains a Q factor of 1.1×10^4.The ChG MKRs demonstrated here are highly promising for resonator-based optical technologies and applications in the mid-IR spectral range.展开更多
As miniature fibre-optic platforms,micro/nanofibres(MNFs)taper-drawn from silica fibres have been widely studied for applications from optical sensing,nonlinear optics to optomechanics and atom optics.While continuous...As miniature fibre-optic platforms,micro/nanofibres(MNFs)taper-drawn from silica fibres have been widely studied for applications from optical sensing,nonlinear optics to optomechanics and atom optics.While continuous-wave(CW)optical waveguiding is frequently adopted,so far almost all MNFs are operated in low-power region(e.g.,<0.1 W).Here,we demonstrate high-power low-loss CW optical waveguiding in MNFs around 1550-nm wavelength.We show that a pristine MNF,even with a diameter down to 410 nm,can waveguide an optical power higher than 10 W,which is about 30 times higher than demonstrated previously.Also,we predict an optical damage threshold of 70 W.In highpower CW waveguiding MNFs,we demonstrate high-speed optomechanical driving of microparticles in air,and second harmonic generation efficiency higher than those pumped by short pulses.Our results may pave a way towards high-power MNF optics,for both scientific research and technological applications.展开更多
Optical micro/nanofibers(MNFs)taper-drawn from silica fibers possess intriguing optical and mechanical properties.Recently,MNF array or MNFs with identical geometries have been attracting more and more attention,howev...Optical micro/nanofibers(MNFs)taper-drawn from silica fibers possess intriguing optical and mechanical properties.Recently,MNF array or MNFs with identical geometries have been attracting more and more attention,however,current fabrication technique can draw only one MNF at a time,with a low drawing speed(typically 0.1 mm/s)and a complicated process for high-precision control,making it inefficient in fabricating multiple MNFs.Here,we propose a parallel-fabrication approach to simultaneously drawing multiple(up to 20)MNFs with almost identical geometries.For fiber diameter larger than 500 nm,measured optical transmittances of all as-drawn MNFs exceed 96.7%at 1550-nm wavelength,with a diameter deviation within 5%.Our results pave a way towards high-yield fabrication of MNFs that may find applications from MNF-based optical sensors,optical manipulation to fiber-to-chip interconnection.展开更多
Dear Editor,As one of the oldest domesticated livestock, pigs were independently domesticated in the Near East and East Asia,approximately 10,000 years ago (Larson et al., 2010).
基金financially supported by the Fellowship of China National Postdoctoral Program for Innovative Talents(No.BX20220357)the National Science Foundation of China (No.52130408)。
文摘Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mechanism of Ti O_(2)and Ti N inclusions in molten Ca O–Si O_(2)–B_(2)O_(3)-based fluorine-free mold flux were explored by in situ single hot thermocouple technology combined with X-ray photoelectron spectroscopy.The results showed that Ti O_(2) inclusions are effectively dissolved by the molten slag within 76 s, during which the original octahedral [Ti O_(6)]^(8-)structures are destroyed and convert to the networker tetrahedral [Ti O_(4)]^(4-)structures. However, the dissolution rate is much lower for Ti N inclusions than for Ti O_(2)inclusions. This can be attributed to the fact that the Ti N particles need to be oxidized and then dissolved in the molten slag to form tetrahedral [Ti O4]4-and octahedral [Ti O_(6)]^(8-)structures during the Ti N inclusion dissolution process, which is accompanied by the generation of a large amount of N_(2)gas. Moreover, Ca Ti O_(3)crystals tend to nucleate and grow on bubble surfaces with sufficient octahedral [Ti O_(6)]^(8-)structures and Ca^(2+)ions, eventually resulting in the molten slag being in a solid–liquid mixed state.
基金financially supported by the Chinese National Natural Science Foundation (41373024)Opening Foundation of State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences (201307)
文摘The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of South China. Here, we present the detailed geochronological, geochemical and petrological analyses for the Jinlongyan(JLY) granite in northwest Fujian Province, southeast China. LA–ICP–MS zircon U–Pb dating yielded a weighted average ^(206)Pb/^(238)U age of 224.1 ±3.3 Ma. The granite is mainly comprised of K-feldspar,plagioclase, quartz, biotite and minor amphibole. It is characterized by enrichments in Rb, Th, REEs(total REE = 295.1–694.3 ppm), and HFSEs(e.g., Zr = 289–520 ppm, Hf = 9.3–15.0 ppm, Y = 36.2–68.2 ppm) but depletions in Ba, Sr, Eu and Ti. The granite is metaluminous to weakly peraluminous and show a clear A-type granite geochemical signature with high SiO_2(70.89 wt%–75.76 wt%), total alkalis(Na_2O + K_2O = 7.51 wt%–8.72 wt%), Ga/Al ratios(10000 Ga/Al = 2.72–3.43). Insitu zircon Hf isotope analysis shows their eHf(t) values ranging from-7.2 to-3.2, with Mesoproterozoic T2DM ages(1308–1525 Ma). Whole-rock Nd isotope data show their eNd(t) values in the range of-9.5 to-9.1 and yield paleoproterozoic TDMages(1606–1985 Ma). These characteristics indicate that the JLY A-type granite magma was formed by the partial melting of Meso-Paleoproterozoic crust rocks in the Cathaysia Block. Our study of the JLY A-type granite, together with other Triassic A-type granitesin South China, defines an extensional environment in the late Triassic which probably was caused by the collision of the South China Block with Indochina Block.
基金This work was supported by the National Key Research and Development Program of China(2016YFB1001300)the National Natural Science Foundation of China(No.11527901)the Fundamental Research Funds for the Central Universities.
文摘Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biological interfaces.While electronic skin continues to achieve higher sensitivity and faster response,its ultimate performance is fundamentally limited by the nature of low-frequency AC currents.Herein,highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers(MNFs)in thin layers of polydimethylsiloxane(PDMS).Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli,the skin-like optical sensors show ultrahigh sensitivity(1870 k·Pa^-1),low detection limit(7 mPa)and fast response(10μs)for pressure sensing,significantly exceeding the performance metrics of state-of-the-art electronic skins.Electromagnetic interference(EMI)-free detection of high-frequency vibrations,wrist pulse and human voice are realized.Moreover,a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated.These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.
基金National Natural Science Foundation of China(11527901,61635009,61922040)Fundamental Research Funds for the Central Universities。
文摘A novel type of mid-IR microresonator,the chalcogenide glass(ChG)microfiber knot resonator(MKR),is demonstrated,showing easy fabrication,fiber-compatible features,resonance tunability,and high robustness.ChG micro fibers with typical diameters around 3μm are taper-drawn from As2S3 glass fibers and assembled into MKRs in liquid without surface damage.The measured Q factor of a typical 824μm diameter ChG MKR is about 2.84×104 at the wavelength of 4469.14 nm.The free spectral range(FSR)of the MKR can be tuned from2.0 nm(28.4 GHz)to 9.6 nm(135.9 GHz)by tightening the knot structure in liquid.Benefitting from the high thermal expansion coefficient of As2S3 glass,the MKR exhibits a thermal tuning rate of 110 pm·℃^-1 at the resonance peak.When embedded in polymethyl methacrylate(PMMA)film,a 551μm diameter MKR retains a Q factor of 1.1×10^4.The ChG MKRs demonstrated here are highly promising for resonator-based optical technologies and applications in the mid-IR spectral range.
基金supported by the National Key Research and Development Project of China(2018YFB2200404)the National Natural Science Foundation of China(62175213,62175122,and 92150302)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(LR21F050002)the Fundamental Research Funds for the Central Universities.
文摘As miniature fibre-optic platforms,micro/nanofibres(MNFs)taper-drawn from silica fibres have been widely studied for applications from optical sensing,nonlinear optics to optomechanics and atom optics.While continuous-wave(CW)optical waveguiding is frequently adopted,so far almost all MNFs are operated in low-power region(e.g.,<0.1 W).Here,we demonstrate high-power low-loss CW optical waveguiding in MNFs around 1550-nm wavelength.We show that a pristine MNF,even with a diameter down to 410 nm,can waveguide an optical power higher than 10 W,which is about 30 times higher than demonstrated previously.Also,we predict an optical damage threshold of 70 W.In highpower CW waveguiding MNFs,we demonstrate high-speed optomechanical driving of microparticles in air,and second harmonic generation efficiency higher than those pumped by short pulses.Our results may pave a way towards high-power MNF optics,for both scientific research and technological applications.
基金supported by the National Natural Science Foundation of China(62175213 and 92150302)the National Key Research and Development Program of China(2018YFB2200404)+2 种基金the New Cornerstone Science Foundation(NCI202216)the Natural Science Foundation of Zhejiang Province(LR21F050002)the Fundamental Research Funds for the Central Universities(2023QZJH27).The authors thank Dong Han for suggestions on the processing of fiber clamps,and also thank Wei Wang for her assistance with SEM.
文摘Optical micro/nanofibers(MNFs)taper-drawn from silica fibers possess intriguing optical and mechanical properties.Recently,MNF array or MNFs with identical geometries have been attracting more and more attention,however,current fabrication technique can draw only one MNF at a time,with a low drawing speed(typically 0.1 mm/s)and a complicated process for high-precision control,making it inefficient in fabricating multiple MNFs.Here,we propose a parallel-fabrication approach to simultaneously drawing multiple(up to 20)MNFs with almost identical geometries.For fiber diameter larger than 500 nm,measured optical transmittances of all as-drawn MNFs exceed 96.7%at 1550-nm wavelength,with a diameter deviation within 5%.Our results pave a way towards high-yield fabrication of MNFs that may find applications from MNF-based optical sensors,optical manipulation to fiber-to-chip interconnection.
基金supported by the National Natural Science Foundation of China (31822052)the National Thousand Youth Talents Plan, the Major Projects of the National Social Science Foundation of China (17ZDA221)
文摘Dear Editor,As one of the oldest domesticated livestock, pigs were independently domesticated in the Near East and East Asia,approximately 10,000 years ago (Larson et al., 2010).
