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Microstructures and Phase Transition in Omphacite: Constraints on the P-T Path of Shuanghe Eclogite (Dabie Orogen)

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Journal of Earth Science 2020年第2期31卷 254-261页

作者： Zhanjun Xie xiangwen liu Zhenmin Jin Zhuoyue Li School of Earth Sciences China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China Engineering Research Center of Nano-Geo Materials of Ministry of Education China University of GeosciencesWuhan 430074China

Omphacite microstructures are important to decipher the metamorphic pressuretemperature(P-T)conditions of eclogite during subduction and exhumation *** we present a systematic microstructural investigation of omphacite using transmission electron microscopy(TEM)in an ultrahigh-pressure(UHP)eclogite sample from Shuanghe,Dabie orogen,*** omphacite can be divided into two phases:(1)Omp-1,exhibits as the main part of omphacite with P2/n space group containing small amount of dislocations and numerous antiphase domains(APDs).(2)Omp-2,shows as banded subgrains with C2/c space group containing large amount of *** two phases of omphacite have almost the same crystallography orientation and bounded by dislocation *** these dislocation walls,we found some barroisite and albite *** barroisite microcrystals contain large amount of dislocations and show a topological relation with host *** the albite microcrystals contain small amount of dislocations and does not show topological relation with *** microstructures could give us the following metamorphic information to constrain the P-T path of eclogite:Firstly,this two omphacite space groups should be evolved from the same precursor C2/c omphacite,which had been underwent strongly plastic deformation during the syn-to late-peak metamorphic ***,the precursor C2/c omphacite began to be retrograded and altered by small amount of barroisite microcrystals along its dislocation walls under the P-T condition of 2.2–2.6 GPa and 650–700℃ at the early amphibole eclogite ***,large amount of Na and other elements were exsolved from some precursor C2/c omphacite subgrains and crystallized numerous albite microcrystals at their boundaries,which is the necessary for the space group of C2/c surviving under the lower P-T conditions(1.7–1.9 GPa and 630–690 C)during the middle amphibole eclogite ***,the rest of precursor C2/c omphacite subgrains w

关键词： microstructure omphacite eclogite TEM P-T path

Rational design of graphyne-based dual-atom site catalysts for CO oxidation

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Nano Research 2023年第1期16卷 343-351页

作者： Zhenwei Zhang Liang Zhang Xiaoyang Wang Yuan Feng xiangwen liu Wenming Sun Department of Chemistry Beijing Key Laboratory for Optical Materials and Photonic DevicesCapital Normal UniversityBeijing 100048China Linyi Vocational University of Science and Technology(Linyi Institute of Industrial Technology) Linyi 276000China Dassault Systemes(Shanghai)Information Technology Co. Ltd.Shanghai 200120China Institute of Analysis and Testing Beijing Academy of Science and Technology(Beijing Center for Physical and Chemical Analysis)Beijing 100094China TianHe Supercomputing Center of Huaihai Linyi 276000China

There are increasing concerns about the environmental impact of rising atmospheric carbon monoxide concentrations,thus it is necessary to develop new catalysts for efficient CO *** on first-principles calculations,the potential ofγ-graphyne(GY)as substrate for metals in the 4th and 5th periods under single-atom and dual-atoms concentration modes has been systematically *** was found that single-atom Co,Ir,Rh,and Ru could effectively oxidate CO molecules,especially for single ***,proper atoms concentration could boost the CO oxidation activity by supplying more reaction centers,such as Rh^(2)/*** was determined that two Rh atoms in Rh^(2)/GY act different roles in the catalytic reaction:one structural and another *** tests suggest that substituting the structural Rh atom in the center of acetylenic ring by Co or Cu atom is a possible way to maintain the reaction performance while reducing the noble metal *** systemic investigation will help in understanding the fundamental reaction mechanisms on GY-based *** emphasize that properly exposed frontier orbital of functional metal atom is crucial in adsorption configuration as well as entire catalytic *** study constructs a workflow and provides valuable information for rational design of CO oxidation catalysts.

关键词： density functional theory calculations CO oxidation single-atom catalyst graphyne dual-atom site catalyst

An Investigation of Dislocation in Olivine Phenocrysts from the Hawaiian Basalts

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Journal of Earth Science 2020年第6期31卷 1183-1189页

作者： Zhuo-Yue Li Da-Peng Wen Yong-Feng Wang xiangwen liu School of Earth Sciences State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China Global Tectonic Center School of Earth SciencesChina University of GeosciencesWuhan 430074China Engineering Research Center of Nano-Geo Materials of Ministry of Education China University of GeosciencesWuhan 430074China

Intracrystalline distortions(like undulose extinction,dislocations,and subgrain boundaries)in olivine from naturally-deformed peridotites are generally taken as signs of dislocation ***,similar features in olivine phenocrysts that have been found in basaltic magmas are still not well *** particular,whether subgrain boundaries in olivine phenocrysts arise from plastic deformation or grain growth is still debated(in the latter case,they are essentially grain boundaries but not subgrain ***,we used hereinafter subgrain-boundary-like structures instead of subgrain boundaries to name this kind of intracrystalline distortion).Here we carried out a detailed study on dislocations and subgrainboundary-like(SG-like)structures in olivine phenocrysts from two Hawaiian basaltic lavas by means of petrographic microscopy,scanning electron microscopy,and transmission electron microscopy(TEM).Abundant and complex dislocation substructures(free dislocations,dislocation walls,and dislocation tangles)were observed in the decorated olivine grains,similar to those in olivine from peridotite xenoliths entrained by the Hawaiian *** measured average dislocation density is(2.9±1.3)×1011 m-2,and is three to five orders of magnitude higher than that in laboratory-synthesized,undeformed *** observations on samples cut across the SG-like structures by FIB(focused ion beam)demonstrated that this kind of structures is made of an array of *** observations clearly indicate that these structures are real subgrain boundaries rather than grain *** facts suggest that the observed high dislocation densities and subgrain boundaries cannot result from crystal crystallization/growth,but can be formed by plastic *** deformation features do not prove that the olivine phenocrysts(and implicitly mantle xenoliths)were deformed after their capture by the basaltic magmas,but can be ascribed to a former deformation event

关键词： olivine phenocryst dislocation subgrain boundary deformation Hawaiian basalts

Au/LaVO_(4)Nanocomposite:Preparation,Characterization,and Catalytic Activity for CO Oxidation

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Nano Research 2008年第1期1卷 46-55页

作者： Junfeng liu Wei Chen xiangwen liu Kebin Zhou Yadong Li Department of Chemistry Tsinghua UniversityBeijing 100084China College of Chemistry and Chemical Engineering Graduate University of the Chinese Academy of SciencesBeijing 100049China

The size of the gold particles is a very important parameter to get active *** paper reports a novel colloidal deposition method to prepare Au/LaVO_(4)nanocomposite catalyst with monodispersed Au colloids and uniform LaVO_(4)nanoplates in nonpolar *** Au colloids with tunable size(such as 2,5,7,11,13,and 16 nm)and LaVO_(4)nanocrystals with well-defi ned shapes were pre-synthesized assisted with oleic acid/*** the following immobilization process,the particle size and shape of Au and LaVO_(4)were nearly ***-prepared Au/LaVO_(4)nanocomposite showed high catalytic activity for CO oxidation at room *** sizes of gold particles were well-defi ned before the immobilization process,size effect of gold particles was easy to be investigated and the results show that 5-nm Au/LaVO_(4)nanocomposite has the highest activity for CO *** synthetic method can be extended further for the preparation of other composite nanomaterials.

关键词： Au/LaVO_(4) nanocomposite colloidal deposition catalytic activity

Factors Limiting the Forecast Skill of the Boreal Summer Intraseasonal Oscillation in a Subseasonal-to-Seasonal Model

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Advances in Atmospheric Sciences 2019年第1期36卷 104-118页

作者： Zheng HE Pangchi HSU xiangwen liu Tongwen WU Yingxia GAO Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Weather Modification Office of Heilongjiang Province Heilongjiang Meteorological Bureau Climate Model Division National Climate CenterChina Meteorological Administration

In this study,we evaluate the forecast skill of the subseasonal-to-seasonal(S2S)prediction model of the Beijing Climate Center(BCC)for the boreal summer intraseasonal oscillation(BSISO).We also discuss the key factors that inhibit the BSISO forecast skill in this *** on the bivariate anomaly correlation coefficient(ACC)of the BSISO index,defined by the first two EOF modes of outgoing longwave radiation and 850-hPa zonal wind anomalies over the Asian monsoon region,we found that the hindcast skill degraded as the lead time *** ACC dropped to below 0.5for lead times of 11 days and longer when the predicted BSISO showed weakened strength and insignificant northward *** identify what causes the weakened forecast skill of BSISO at the forecast lead time of 11 days,we diagnosed the main mechanisms responsible for the BSISO northward *** same analysis was also carried out using the observations and the outputs of the four-day forecast lead that successfully predicted the observed northward-propagating *** found that the lack of northward propagation at the 11-day forecast lead was due to insufficient increases in low-level cyclonic vorticity,moistening and warm temperature anomalies to the north of the convection,which were induced by the interaction between background mean flows and BSISO-related anomalous *** BCC S2S model can predict the background monsoon circulations,such as the low-level southerly and the northerly and easterly vertical shears,but has limited capability in forecasting the distributions of circulation and moisture anomalies.

关键词： BCC S2S model boreal summer intraseasonal oscillation forecast skill northward propagation

A novel structure of ultra-high-loading small moleculesencapsulated ZIF-8 colloid particles

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Nano Research 2024年第4期17卷 2929-2940页

作者： Pengfei Duan Yunhe An Xiaoxiao Wei Yanjie Tian Di Guan xiangwen liu Lanqun Mao Institute of Analysis and Testing Beijing Academy of Science and Technology(Beijing Center for Physical and Chemical Analysis)Beijing 100089China College of Chemistry Beijing Normal UniversityBeijing 100875China

The safety of nanoparticle-based drug delivery systems(DDSs)for cancer treatment is still a challenge,restricted by the intrinsic cytotoxicity of drug carriers and leakage of loaded ***,we propose a novel nanocarrier’s cytotoxicity avoidance strategy by synthesizing an encapsulation core–shell structure of zeolitic imidazolate framework-8(ZIF-8)-based colloid particles(CPs)with an amorphous ZIF-8 *** encapsulation structure achieves an ultra-high loading rate(LR)of 90%(i.e.,9 mg doxorubicin(DOX)per 1 mg ZIF-8)for DOX and the protection of DOX from ***,to deliver unit-dose drug,this ultra-high LR of 90%significantly reduces the usage of ZIF-8 to 1.2%(2 orders of magnitude)compared to that of DOX@ZIF-8 with a 10%LR,in which cytotoxicity of ZIF-8 could well below the safety limit and then be relatively ***,drug delivery efficacy,scale-up ability,and universality of this encapsulation structure have been further *** findings suggest the great potential of this ZIF-8-based encapsulation core–shell structure in the field of drug delivery.

关键词： metal-organic frameworks zeolitic imidazolate framework-8(ZIF-8) drug delivery nanoparticles nanostructures

Improvement of 6–15 Day Precipitation Forecasts Using a Time-Lagged Ensemble Method

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Advances in Atmospheric Sciences 2014年第2期31卷 293-304页

作者： JIE Weihua WU Tongwen WANG Jun LI Weijing liu xiangwen University of Chinese Academy of Sciences Beijing Climate Center China Meteorological Administration Department of Earth and Atmospheric Sciences University of Nebraska–Lincoln NE 68588 - 0340 USA

A time-lagged ensemble method is used to improve 6-15 day precipitation forecasts from the Beijing Climate Center Atmospheric General Circulation Model,version *** approach averages the deterministic predictions of precipitation from the most recent model run and from earlier runs,all at the same forecast valid *** lagged average forecast （LAF） method assigns equal weight to each ensemble member and produces a forecast by taking the ensemble *** analyses of the Equitable Threat Score,the Hanssen and Kuipers Score,and the frequency bias indicate that the LAF using five members at time-lagged intervals of 6 h improves 6-15 day forecasts of precipitation frequency above 1 mm d-1 and 5 mm d-1 in many regions of China,and is more effective than the LAF method with selection of the time-lagged interval of 12 or 24 h between ensemble *** particular,significant improvements are seen over regions where the frequencies of rainfall days are higher than about 40％-50％ in the summer season; these regions include northeastern and central to southern China,and the southeastem Tibetan Plateau.

关键词： time-lagged ensemble system lagged average forecast 6-15 day forecasts precipitation

Progress of MJO Prediction at CMA from Phase I to Phase II of the Sub-Seasonal to Seasonal Prediction Project

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Advances in Atmospheric Sciences 2023年第10期40卷 1799-1815页

作者： Junchen YAO xiangwen liu Tongwen WU Jinghui YAN Qiaoping LI Weihua JIE Center for Earth System Modeling and Prediction of China Meteorological Administration Beijing 100081China

As one of the participants in the Subseasonal to Seasonal(S2S)Prediction Project,the China Meteorological Administration(CMA)has adopted several model versions to participate in the S2S *** study evaluates the models’capability to simulate and predict the Madden-Julian Oscillation(MJO).Three versions of the Beijing Climate Center Climate System Model(BCC-CSM)are used to conduct historical simulations and re-forecast experiments(referred to as EXP1,EXP1-M,and EXP2,respectively).In simulating MJO characteristics,the newly-developed high-resolution BCC-CSM outperforms its *** terms of MJO prediction,the useful prediction skill of the MJO index is enhanced from 15 days in EXP1 to 22 days in EXP1-M,and further to 24 days in *** the first forecast week,the better initial condition in EXP2 largely contributes to the enhancement of MJO prediction ***,during forecast weeks 2–3,EXP2 shows little advantage compared with EXP1-M because the increased skill at MJO initial phases 6–7 is largely offset by the degraded skill at MJO initial phases 2–*** at initial phases 2–3,EXP1-M skillfully captures the wind field and Kelvin-wave response to MJO convection,leading to the highest prediction skill of the *** results reveal that,during the participation of the CMA models in the S2S Project,both the improved model initialization and updated model physics played positive roles in improving MJO *** efforts should focus on improving the model physics to better simulate MJO convection over the Maritime Continent and further improve MJO prediction at long lead times.

关键词： Madden-Julian Oscillation(MJO) Subseasonal to Seasonal(S2S) prediction skill improvement initial phase

Sub-seasonal to Seasonal Hindcasts of Stratospheric Sudden Warming by BCC_CSM1.1(m):A Comparison with ECMWF

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Advances in Atmospheric Sciences 2019年第5期36卷 479-494页

作者： Jian RAO Rongcai REN Haishan CHEN xiangwen liu Yueyue YU Yang YANG Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and Technology State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Fredy and Nadine Herrmann Institute of Earth Sciences The Hebrew University of Jerusalem Edmond J.Safra Campus Climate Model Division National Climate Center China Meteorological Administration Institute of Urban Meteorology China Meteorological Administration

This study focuses on model predictive skill with respect to stratospheric sudden warming(SSW) events by comparing the hindcast results of BCC_CSM1.1(m) with those of the ECMWF's model under the sub-seasonal to seasonal prediction project of the World Weather Research Program and World Climate Research Program. When the hindcasts are initiated less than two weeks before SSW onset, BCC_CSM and ECMWF show comparable predictive skill in terms of the temporal evolution of the stratospheric circumpolar westerlies and polar temperature up to 30 days after SSW onset. However, with earlier hindcast initialization, the predictive skill of BCC_CSM gradually decreases, and the reproduced maximum circulation anomalies in the hindcasts initiated four weeks before SSW onset replicate only 10% of the circulation anomaly intensities in observations. The earliest successful prediction of the breakdown of the stratospheric polar vortex accompanying SSW onset for BCC_CSM(ECMWF) is the hindcast initiated two(three) weeks earlier. The predictive skills of both models during SSW winters are always higher than that during non-SSW winters, in relation to the successfully captured tropospheric precursors and the associated upward propagation of planetary waves by the model initializations. To narrow the gap in SSW predictive skill between BCC_CSM and ECMWF, ensemble forecasts and error corrections are performed with BCC_CSM. The SSW predictive skill in the ensemble hindcasts and the error corrections are improved compared with the previous control forecasts.

关键词： sub-seasonal to seasonal(S2S)hindcast stratospheric sudden warming BCC_CSM ensemble forecast error correction