Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating techniques.The crushing in vacuo results pr...Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating techniques.The crushing in vacuo results provide information to directly constrain the timing of fluid activity and the age of amphibolite-facies retrogression.The stepwise heating results could further be used to decipher the thermal history of the UHP rocks.Amphiboles from amphibolites and quartz vein within garnetamphibolite lens analyzed by in vacuo crushing yield similarly shaped age spectra and exhibit relatively flat age plateaus for the last several steps.The characteristics of gas release patterns and geochronological data testify to the presence of significant excess40Ar within the fluid inclusions.The age plateaux with weighted mean ages（WMA） ranges from 488 to 476 Ma for amphiboles and 403 Ma for quartz（2σ）.These data points constitute amphibole WMA yielding excellent isochrons with isochron ages of 469 and 463 Ma with initial40Ar/36Ar ratios of 520 and 334,respectively.The isochron ages are interpreted to represent initial amphibolite-facies retrogression.The data points constituting the quartz age plateaux give an isochron age of 405 Ma with initial40Ar/36Ar ratio of 295,recording a significant aqueous fluid flow episode during the early Devonian.Age spectra obtained by stepwise heating of amphibole residues remaining after crushing experiments are characterized by younger and relatively complex age spectra,which are probably influenced by the combined effects of resetting argon and/or mineral inclusions.Nevertheless,we note that the spectra shapes have features in common:excluding the last two steps,minimum apparent ages are found at temperatures of around 500 ℃,corresponding to319 and 249 Ma,perhaps representing the time of isotopic resetting or resulting from release gas from mineral inclusions of,e.g.,biotite or feldspar.Maximum apparent ages are obtained at temperatures of around 800℃,corresponding to 418 and 413 Ma,which probably reflect mixed ages of radiogenic resetting and original amphibole.These results indicate that the Yuka eclogites and their retrogressed equivalents were overprinted by multiple thermal events in the Silurian and possibly as young as the Triassic.展开更多
ABSTRACT： The joint methods of ^40Ar/^39Ar laser stepwise heating and in vacuo crushing have been applied to date amphiboles from the North Qaidam ultra-high pressure metamorphic amphibolites. Two amphibole samples a...ABSTRACT： The joint methods of ^40Ar/^39Ar laser stepwise heating and in vacuo crushing have been applied to date amphiboles from the North Qaidam ultra-high pressure metamorphic amphibolites. Two amphibole samples analyzed by laser heating yielded saddle-shaped age spectra with total gas ages of 574.5±2.5 and 562.5=±2.5 Ma. These ages are much older than the reported zircon U-Pb ages （-495 Ma） from Yuka eclogite, indicating the presence of excess ^40Ar. In order to decipher the occur- rence of excess ^40Ar and constrain the age of amphibolite-facies retrogression, two duplicate amphibole samples were further employed for ^40Ar/^39Ar in vacuo crushing analyses. Both samples exhibit similar monotonically declining release spectra, which are characterized by rapid decline of anomalously old apparent ages in the early steps. The data of the late steps yielded concordant apparent ages with pla- teau ages of 460.9±1.2 and 459.6±1.8 Ma. We interpret that gases released in the early steps derive from the significant excess ^40Ar containing secondary fluid inclusions （SFIs） due to their distribution characteristics along cracks leading to be easily extracted, whereas those released in the later steps rep- resent the contribution of the small primary fluid inclusions （PFIs）.展开更多
Lithium(Li)metal is an attractive anode material with high capacity(3860 mAh g^(−1))and low potential(−3.04 V vs.standard hydrogen electrode)that shows highly promising for applications requiring high energy density.H...Lithium(Li)metal is an attractive anode material with high capacity(3860 mAh g^(−1))and low potential(−3.04 V vs.standard hydrogen electrode)that shows highly promising for applications requiring high energy density.However,the low electrochemical potential of Li metal makes it extremely reactive and inevitably forming a native oxidized layer in the ambient environment and repeatedly being consumed when exposed to liquid electrolytes.It is therefore beneficial to replace the poorly controlled native passivation layer with a tailored artificial SEI to improve interface management between Li and electrolyte and enhance the stability of Li metal battery.Here,we use an integrated glovebox-atomic layer deposition(ALD)-X-ray photoelectron spectroscopy(XPS)setup to in-situ investigating the pristine Li surface and the surface composition after Ar,H_(2)O_(2),N_(2)and NH_(3)plasma treatment processes.We find that the pristine Li foil is naturally being covered with a native oxidized layer,which is mainly composed of LiOH,Li_(2)O and Li_(2)CO_(3).These investigated plasmas can efficiently remove the oxidized layer from the Li metal surface,in which metallic Li surface is obtained after Ar or H2 plasma treatments,where Ar plasma is more efficient.While O_(2)plasma treatment produces a Li_(2)O layer,and N_(2)or NH_(3)plasma treatment leads to a Li3N(including a certain amount of LiON)layer on the Li surface.When employing the representative metallic Li(by Ar plasma treatment),Li_(2)O layer coated Li(by O_(2)plasma treatment)and Li3N layer coated Li(by N_(2)plasma treatment)foils as electrodes in symmetric Li metal batteries,the Li3N coated Li electrode exhibits much higher stability than that of metallic and Li_(2)O layer coated Li foils.Improved electrochemical performance has also been achieved in LiMn_(2)O_(4)(LMO)||Li full cells using Li anode with Li3N protective coating layer.Our work reveals the detailed process of surface engineering of Li metal anodes with plasma treatments by in vacuo XPS,which may also be extended to other gas-treatment or plasma-treatment for stabilization of high energy density Li metal anodes and other metal-based anodes.展开更多
Pneumonia remains the single leading cause of childhood death worldwide.Despite the commercial availability of multiple pneumococcal conjugate vaccines(PCVs),high dosage cost and supply shortages prevent PCV delivery ...Pneumonia remains the single leading cause of childhood death worldwide.Despite the commercial availability of multiple pneumococcal conjugate vaccines(PCVs),high dosage cost and supply shortages prevent PCV delivery to much of the developing world.The current work presents high-yield pneumococcal conjugates that are immunogenic in animals and suitable for use in human vaccine development.The 13-valent pneumococcal conjugate vaccine(PCV-13)investigated in this research incorporated serotypes 1,3,4,5,6A,6B,7F,9V,14,18C,19A,19F,and 23F.Pneumococcal polysaccharides(PnPSs)and CRM197 carrier protein were produced and purified in-house,and used to prepare PnPS-CRM conjugates using unique,cyanide-free,in vacuo glycation conjugation methods.In vitro characterization confirmed the generation of higher molecular weight PnPS-CRM conjugates low in free protein.In vivo animal studies were performed to compare PnuVax's PCV-13 to the commercially available PCV-13,Prevnar®13(Pfizer,USA).A boost dose was provided to all groups post-dose 1 at t?14 days.Post-dose 2 results at t?28 days showed that all 13 serotypes in PnuVax's PCV-13 were boostable.Per serotype IgG GMCs demonstrated that PnuVax's PCV-13 is immunogenic for all 13 serotypes,with 10 of the 13 serotypes statistically the same or higher than Prevnar®13 post-dose 2.As a result,the novel polysaccharideprotein conjugates developed in this work are highly promising for use in human PCV development.The in vacuo conjugation technique applied in this work could also be readily adapted to develop many other conjugate vaccines.展开更多
基金funded by the Chinese Academy Sciences-Royal Netherlands Academy of Arts and Sciences(CAS-KNAW)Joint PhD Training Programme(ISK/3523/PhD)the joint research project between the CAS and the De Koninklijke Nederlandse Akademie van Wetenschappen(06CDP002)
文摘Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating techniques.The crushing in vacuo results provide information to directly constrain the timing of fluid activity and the age of amphibolite-facies retrogression.The stepwise heating results could further be used to decipher the thermal history of the UHP rocks.Amphiboles from amphibolites and quartz vein within garnetamphibolite lens analyzed by in vacuo crushing yield similarly shaped age spectra and exhibit relatively flat age plateaus for the last several steps.The characteristics of gas release patterns and geochronological data testify to the presence of significant excess40Ar within the fluid inclusions.The age plateaux with weighted mean ages（WMA） ranges from 488 to 476 Ma for amphiboles and 403 Ma for quartz（2σ）.These data points constitute amphibole WMA yielding excellent isochrons with isochron ages of 469 and 463 Ma with initial40Ar/36Ar ratios of 520 and 334,respectively.The isochron ages are interpreted to represent initial amphibolite-facies retrogression.The data points constituting the quartz age plateaux give an isochron age of 405 Ma with initial40Ar/36Ar ratio of 295,recording a significant aqueous fluid flow episode during the early Devonian.Age spectra obtained by stepwise heating of amphibole residues remaining after crushing experiments are characterized by younger and relatively complex age spectra,which are probably influenced by the combined effects of resetting argon and/or mineral inclusions.Nevertheless,we note that the spectra shapes have features in common:excluding the last two steps,minimum apparent ages are found at temperatures of around 500 ℃,corresponding to319 and 249 Ma,perhaps representing the time of isotopic resetting or resulting from release gas from mineral inclusions of,e.g.,biotite or feldspar.Maximum apparent ages are obtained at temperatures of around 800℃,corresponding to 418 and 413 Ma,which probably reflect mixed ages of radiogenic resetting and original amphibole.These results indicate that the Yuka eclogites and their retrogressed equivalents were overprinted by multiple thermal events in the Silurian and possibly as young as the Triassic.
基金funded by the National Natural Science Foundation of China (Nos. 41703054, 41503053)the Guangxi Natural Science Foundation Program (Nos. 2016GXNSFCA380022, 2014GXNSFBA118231)the Chinese Academy of Sciences-Royal Netherlands Academy of Arts and Sciences Joint PhD Training Programme (No. O8PhD-08)
文摘ABSTRACT： The joint methods of ^40Ar/^39Ar laser stepwise heating and in vacuo crushing have been applied to date amphiboles from the North Qaidam ultra-high pressure metamorphic amphibolites. Two amphibole samples analyzed by laser heating yielded saddle-shaped age spectra with total gas ages of 574.5±2.5 and 562.5=±2.5 Ma. These ages are much older than the reported zircon U-Pb ages （-495 Ma） from Yuka eclogite, indicating the presence of excess ^40Ar. In order to decipher the occur- rence of excess ^40Ar and constrain the age of amphibolite-facies retrogression, two duplicate amphibole samples were further employed for ^40Ar/^39Ar in vacuo crushing analyses. Both samples exhibit similar monotonically declining release spectra, which are characterized by rapid decline of anomalously old apparent ages in the early steps. The data of the late steps yielded concordant apparent ages with pla- teau ages of 460.9±1.2 and 459.6±1.8 Ma. We interpret that gases released in the early steps derive from the significant excess ^40Ar containing secondary fluid inclusions （SFIs） due to their distribution characteristics along cracks leading to be easily extracted, whereas those released in the later steps rep- resent the contribution of the small primary fluid inclusions （PFIs）.
基金FWO-Vlaanderen(No.GO87418N and 1S68518N)BOF-GOA UGent(No.01G01019)Solvay SA for financial support。
文摘Lithium(Li)metal is an attractive anode material with high capacity(3860 mAh g^(−1))and low potential(−3.04 V vs.standard hydrogen electrode)that shows highly promising for applications requiring high energy density.However,the low electrochemical potential of Li metal makes it extremely reactive and inevitably forming a native oxidized layer in the ambient environment and repeatedly being consumed when exposed to liquid electrolytes.It is therefore beneficial to replace the poorly controlled native passivation layer with a tailored artificial SEI to improve interface management between Li and electrolyte and enhance the stability of Li metal battery.Here,we use an integrated glovebox-atomic layer deposition(ALD)-X-ray photoelectron spectroscopy(XPS)setup to in-situ investigating the pristine Li surface and the surface composition after Ar,H_(2)O_(2),N_(2)and NH_(3)plasma treatment processes.We find that the pristine Li foil is naturally being covered with a native oxidized layer,which is mainly composed of LiOH,Li_(2)O and Li_(2)CO_(3).These investigated plasmas can efficiently remove the oxidized layer from the Li metal surface,in which metallic Li surface is obtained after Ar or H2 plasma treatments,where Ar plasma is more efficient.While O_(2)plasma treatment produces a Li_(2)O layer,and N_(2)or NH_(3)plasma treatment leads to a Li3N(including a certain amount of LiON)layer on the Li surface.When employing the representative metallic Li(by Ar plasma treatment),Li_(2)O layer coated Li(by O_(2)plasma treatment)and Li3N layer coated Li(by N_(2)plasma treatment)foils as electrodes in symmetric Li metal batteries,the Li3N coated Li electrode exhibits much higher stability than that of metallic and Li_(2)O layer coated Li foils.Improved electrochemical performance has also been achieved in LiMn_(2)O_(4)(LMO)||Li full cells using Li anode with Li3N protective coating layer.Our work reveals the detailed process of surface engineering of Li metal anodes with plasma treatments by in vacuo XPS,which may also be extended to other gas-treatment or plasma-treatment for stabilization of high energy density Li metal anodes and other metal-based anodes.
文摘Pneumonia remains the single leading cause of childhood death worldwide.Despite the commercial availability of multiple pneumococcal conjugate vaccines(PCVs),high dosage cost and supply shortages prevent PCV delivery to much of the developing world.The current work presents high-yield pneumococcal conjugates that are immunogenic in animals and suitable for use in human vaccine development.The 13-valent pneumococcal conjugate vaccine(PCV-13)investigated in this research incorporated serotypes 1,3,4,5,6A,6B,7F,9V,14,18C,19A,19F,and 23F.Pneumococcal polysaccharides(PnPSs)and CRM197 carrier protein were produced and purified in-house,and used to prepare PnPS-CRM conjugates using unique,cyanide-free,in vacuo glycation conjugation methods.In vitro characterization confirmed the generation of higher molecular weight PnPS-CRM conjugates low in free protein.In vivo animal studies were performed to compare PnuVax's PCV-13 to the commercially available PCV-13,Prevnar®13(Pfizer,USA).A boost dose was provided to all groups post-dose 1 at t?14 days.Post-dose 2 results at t?28 days showed that all 13 serotypes in PnuVax's PCV-13 were boostable.Per serotype IgG GMCs demonstrated that PnuVax's PCV-13 is immunogenic for all 13 serotypes,with 10 of the 13 serotypes statistically the same or higher than Prevnar®13 post-dose 2.As a result,the novel polysaccharideprotein conjugates developed in this work are highly promising for use in human PCV development.The in vacuo conjugation technique applied in this work could also be readily adapted to develop many other conjugate vaccines.
