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Applications of mercury stable isotopes for tracing volcanism in the geologic record

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science China earth sciences 2024年第5期67卷 1436-1458页

作者： Qing GONG Ming-Xing LING Wang ZHENG State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China school of earth system science Institute of Surface-Earth System ScienceTianjin UniversityTianjin 300072China

Mercury(Hg)enrichments in ancient sediments have been used as a proxy of volcanism,especially large igneous province(LIP)***,considering the existence of other potential Hg sources besides volcanoes and the diverse factors(e.g.,organic matters,clay minerals,sulfide minerals and Fe oxides)that can affect Hg sequestration,there are considerable uncertainties to simply regard sedimentary Hg anomalies as signatures of volcanic *** stable isotopes,a promising tool for tracing the origins and transformations of Hg,have been increasingly used for determining the causes of Hg spikes and understanding the geochemical behavior of Hg in the geologic *** date,lots of researches have applied Hg concentrations and Hg isotopes to identify LIP volcanisms linking with significant geological events such as mass extinctions,ocean anoxic events and other environmental perturbations that mainly occurred in the ***,the results in previous studies clearly show that not all Hg enrichments are derived from volcanic inputs,which emphasize the need for more caution in using Hg as a fingerprint of *** a better understanding of Hg isotopes in the future,there will be important implications for Hg isotopes to reconstruct volcanic activities in the rock records and their impacts on biological evolution.

关键词： Mercury stable isotopes Large igneous province Mass extinction event Ocean anoxic event

Elucidation of the last steps of photo-ammonification:analytical method development and mechanism elucidation

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Frontiers of Environmental science & Engineering 2024年第8期18卷 101-106页

作者： Yingjing Miao Hui Wang Chunpeng Yang Ruochun Zhang Hao Zhang Peizhe Sun school of Environmental science and Engineering Tianjin UniversityTianjin 300072China SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China school of earth system science Tianjin UniversityTianjin 300072China

The mechanisms underlying the photo-ammonification of nitrogenous organic compounds(NOCs)remain unclear,partly due to the analytical challenges of small NOC *** study introduced a simple methodology for accurately and simultaneously quantifying multiple small NOCs during ammonification *** developed method employed phenyl isothiocyanate as derivatization reagents,followed by high-performance liquid chromatography analysis to measure primary and secondary amines,amides,as well as NH4+over variable photo-ammonification *** our experimental setup,vacuum ultraviolet(VUV)irradiation serves as the controlled reaction environment to simulate harsh photo-ammonification *** NOCs,including pyridine,N,N-dimethylformamide,and acrylonitrile,were chosen due to their structural diversity and environmental relevance as model *** method was able to achieve excellent nitrogen mass balance,and revealed that the last steps of photo-ammonification involved oxidation of nitrogen-adjacent carbon to amide followed by the cleavage of N-C *** novel method may also help quantitative investigation of nitrogen transformations in different environmental contexts.

关键词： Ammonification NOCs Amines Nitrogen mass balance

Analysis of amino acid enantiomers in ambient aerosols:Effects and removal of coexistent aerosol matrix

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Journal of Environmental sciences 2024年第3期137卷 732-740页

作者： Ying Li Xiaoying Li Libin Wu Luhan Shi ShanWang Pingqing Fu Yingyi Zhang Senchao Lai The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSchool of Environment and EnergySouth China University of TechnologyGuangzhou 510006China Institute of Surface-earth system science School of Earth System ScienceTianjin UniversityTianjin 300072China now at Hong Kong university of science and Technology Hong Kong 00852China

Amino acids(AAs)including D-and L-enantiomers are a group of organic nitrogen species in ambient *** to the low abundances of AAs(level of ng/m^(3))and the matrix effects by coexistent components,it is challenging to quantify AA enantiomers in ambient aerosols especially under pollution *** this study,we present an optimized method for analyzing AA enantiomers in atmospheric aerosol samples including a pretreatment process and the detection by high performance liquid chromatography coupled to a fuorescence detector(HPLC-FLD).Matrix effects caused by coexistent chemicals on AA enantiomers analysis in ambient aerosol samples were investigated especially for those collected in pollution *** results revealed that the determination of AA enantiomers is significantly affected by the coexistent organic carbon(as a proxy of organic matter)and water-soluble ion of NH_(4)^(+).To remove the matrix effects,we applied a pretreatment using the solid phase extraction column coupled with alkaline adjustment to sample *** pretreatment,18 AAs including 6 pairs of D-and L-enantiomers(i.e.,leucine,isoleucine,valine,alanine,serine,and aspartic acid)can be successfully separated and quantified in aerosol samples by *** recoveries are in the range of 67%-106%.This method was successfully applied to the urban aerosol samples from pollution and non-pollution periods for AA enantiomers *** suggest that the concentrations of D-AAs and the ratio of D-AA/L-AA are indicative of the contribution of bacterial sources and the infuence of biomass burning.

关键词： Amino acid enantiomers Atmospheric aerosol Organic carbon Ammonia Chiral ratio

Constraints on what controls millennial-scale basin-wide denudation across mountain belts, Asia

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science China earth sciences 2024年

作者： Ye YANG Steven A.BINNIE Sheng XU Cong-Qiang LIU Tibor J.DUNAI Institute of Surface-earth system science School of Earth System Science Tianjin University Institute of Geology and Mineralogy University of Cologne

The terrestrial cosmogenic nuclide dataset consisting of 123310Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate,tectonics and topography on earth-surface denudation processes.10Be-derived basin-wide denudation rates were recalculated using a Monte Carlo simulation approach that relied on pixel-by-pixel production *** rates derived span four orders of magnitude,from 7.4±0.7 mm kyr-1（1σ;Central Tibetan Plateau） to 9,646+777744mm kyr-1（1σ;Southern Tibetan Plateau）,with a median of 186 mm *** our results with the traditional basin-wide production rate scaling model using a centroid coordinate and mean elevation,suggests that 96.6%of production rates will be underestimated using the latter method,especially for basins with a large *** bias between both methods reaches as large as 40%,caused by basin hypsometry and the nonlinear scaling of production rate with elevation and *** of the correlations between uniformly recalculated denudation rates and tectonics,climate,topography,and rock lithology will facilitate the extrapolation of denudation rates in unknown basins using available *** the perspective of local scales,precipitation coupled with neotectonics-driven landslides is likely the most influential factor in subtropical Taiwan Island,while topography primarily constrains surface denudation rates in the eastern Tibetan Plateau within a narrow range of *** highland regions with glacier coverage,such as the Pamir,central and southern Tibetan Plateau,high denudation rates are affected by glaciation,whereas lower precipitation and high erosion base level may limit river incision and evolving relief in the Central Tibetan *** contrast to local-scale findings highlighting a dominant factor constraining denudation rate,our large-scale quantitative analyses across the Asian mountain belts finds that （1） topographic metrics including

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Investigation of Ce/BEA as a passive NO_(x)adsorber:*** occurrences of cerium and adsorption behavior

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Journal of Rare earths 2024年第7期42卷 1265-1271,I0003页

作者： Minghui Yu Yiying Ding Xiaojie Yu Siwei Yan Meiqing Shen Jianqiang Wang Jun Wang Gurong Shen school of Materials science and Engineering Tianjin UniversityTianjin300350China school of Chemical Engineering and Technology Tianjin UniversityTianjin300350China National Rare earth Catalysis Research Institute Dongying257000China

Ce/BEA has great potential as a passive NO_(x)absorber(PNA)to reduce the NO_(x)emissions during the cold start phase especially in diesel engine for its high resistance to CO and suitable NO_(x)desorption temperature ***,as a novel material,its physical and chemical properties still remain *** this work,Ce/BEA was synthesized by ion-exchange method to identify the active species in NO_(x)adsorption,compared with aggregated Ce species in Ce/SiAlO_(x) prepared by impregnation method.X-ray diffraction(XRD),high resolution-transmission electron microscopy(HR-TEM)and aberration-corrected-scanning transmission electron microscopy(AC-STEM)were performed to confirm the isolated single atom formation of Ce species in Ce/***-vis diffraction reflection spectra(DRS)and X-ray photoelectron spectroscopy(XPS)were conducted to find the difference of chemical environment between the isolated Ce species and aggregated *** performance evaluation and temperature programmed reduction of hydrogen(H_(2)-TPR)results show the high NO_(x)storage capacity and active oxygen species quantity in Ce/*** is also found that the main NO_(x)adsorption species are Ce^(4+)-O^(∗)rather than Ce^(3+).NO_(x)-diffuse reflectance infrared Fourier transform spectroscopy(NO_(x)-DRIFTS)confirms that the bidentate nitrite species are the critical NO_(x)adsorption intermediates and the conception of NO_(x)adsorption and desorption processes is proposed.

关键词： Passive NO_(x)absorber Ce/BEA Isolated Ce species Rare earths

Investigation of Ce/BEA as a passive NO_(x)adsorber:*** aging deactivation mechanism

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Journal of Rare earths 2024年第8期42卷 1524-1530,I0004页

作者： Yiying Ding Minghui Yu Xiaojie Yu Meiqing Shen Jianqiang Wang Jun Wang Gurong Shen school of Chemical Engineering and Technology Tianjin UniversityTianjin300350China school of Materials science and Engineering Tianjin UniversityTianjin300350China National Rare earth Catalysis Research Institute Dongying257000China

Ce/BEA has the potential to be applied as a novel passive NO_(x)absorber(PNA)in the after-treatment of vehicles due to its considerable NO_(x)storage ***,as a vehicle exhaust after-treatment material,it must withstand the test of long-term hydrothermal *** work examined the deactivation mechanism of Ce/BEA during hydrothermal aging.3.0 wt%Ce/BEA was prepared using the ionexchange method,and then subjected to hydrothermal treatment at 650℃with 10%H_(2)O for 1-12 h to obtain samples with different aging *** comparison,the H-BEA support was aged under the same ***-Emmett-Teller(BET)method,X-ray diffraction(XRD),NH_(3)temperature programmed reduction(NH_(3)-TPD),^(27)Al MAS nuclear magnetic resonance(^(27)Al MAS NMR),H_(2)temperature programmed reduction(H_(2)-TPR),and high resolution-transmission electron microscopy(HR-TEM)were performed to characterize the changes in PNA performance,structure,Ce species,and *** HR-TEM and H_(2)-TPR results show that CeO_(x)particles appear after hydrothermal aging,which results from the detachment and aggregation of active Ce *** on the^(27)Al MAS NMR results,we conclude that BEA zeolite dealumination leads to the loss of acidic sites and the transformation of active Ce species on the acidic sites into the less active CeO_(x).This is the primary reason for the hydrothermal aging deactivation of Ce/BEA.

关键词： Passive NO_(x)adsorber Ce/BEA Hydrothermal aging CeO_(x) Dealumination Rare earths

Principle of Hydrogen Isotope Geochemistry Paleo-altimeter and its Potential in Reconstructing Paleo-elevation of the Southeastern Tibetan Plateau

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1051-1063页

作者： CUI Fengzhen LIU-ZENG Jing LI Yunshuai XU Qiang TANG Maoyun WANG Heng SUN Zhaotong school of earth system science Tianjin UniversityTianjin 300072China State Key Laboratory of earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China school of earth science and Technology Southwest Petroleum UniversityChengdu 610500China Chongqing earthquake Agency Chongqing 401147China

The reconstruction of paleo-elevation serves a dual purpose to enhance our comprehension of geodynamic processes affecting terrestrial landforms and to contribute significantly to the interpretation of atmospheric circulation and *** oxygen(δ~(18)O_w)and deuterium(δD_w)isotopes in atmospheric precipitation are systematically depleted with the increase of altitude,which are typical and widely applicated *** utilization of hydrogen isotope of hydrous silicate minerals within the shear zone system,volcanic glass,and plant leaf wax alkanes offers valuable insights for addressing evaporation and *** this paper,we review the principle,application conditions,and influencing factors of the hydrogen isotope *** addition,we discuss the feasibility of utilizing this technique for quantitatively estimating the paleo-elevation of the southeastern Tibetan Plateau,where multiple shear zones extend over hundred kilometers parallel to the topographic gradient.

关键词： paleo-elevation hydrogen isotope hydrous silicate minerals volcanic glass Tibetan Plateau

Event-triggered adaptive tracking control of a class of nonlinear systems with asymmetric time-varying output constraints

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Frontiers of Information Technology & Electronic Engineering 2024年第8期25卷 1134-1144页

作者： Yitao YANG Lidong ZHANG school of science Tianjin University of TechnologyTianjin 300384China

This article investigates the event-triggered adaptive neural network(NN)tracking control problem with deferred asymmetric time-varying(DATV)output *** deal with the DATV output constraints,an asymmetric time-varying barrier Lyapunov function(ATBLF)is first built to make the stability analysis and the controller construction ***,an event-triggered adaptive NN tracking controller is constructed by incorporating an error-shifting function,which ensures that the tracking error converges to an arbitrarily small neighborhood of the origin within a predetermined settling time,consequently optimizing the utilization of network *** is theoretically proven that all signals in the closed-loop system are semi-globally uniformly ultimately bounded(SGUUB),while the initial value is outside the constraint ***,a single-link robotic arm(SLRA)application example is employed to verify the viability of the acquired control algorithm.

关键词： Adaptive control Deferred asymmetric time-varying output constraints Error-shifting function Event-triggered control

Enhancing Deep Learning Soil Moisture Forecasting Models by Integrating Physics-based Models

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Advances in Atmospheric sciences 2024年第7期41卷 1326-1341页

作者： Lu LI Yongjiu DAI Zhongwang WEI Wei SHANGGUAN Nan WEI Yonggen ZHANG Qingliang LI Xian-Xiang LI school of Atmospheric sciences Sun Yat-sen UniversityGuangzhou 510275China Southern Marine science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Guangzhou 510275China Institute of Surface-earth system science School of Earth System ScienceTianjin UniversityTianjin 300072China College of Computer science and Technology Changchun Normal UniversityChangchun 130123China

Accurate soil moisture(SM)prediction is critical for understanding hydrological ***-based(PB)models exhibit large uncertainties in SM predictions arising from uncertain parameterizations and insufficient representation of land-surface *** addition to PB models,deep learning(DL)models have been widely used in SM predictions ***,few pure DL models have notably high success rates due to lacking physical ***,we developed hybrid models to effectively integrate the outputs of PB models into DL models to improve SM *** this end,we first developed a hybrid model based on the attention mechanism to take advantage of PB models at each forecast time scale(attention model).We further built an ensemble model that combined the advantages of different hybrid schemes(ensemble model).We utilized SM forecasts from the Global Forecast system to enhance the convolutional long short-term memory(ConvLSTM)model for 1–16 days of SM *** performances of the proposed hybrid models were investigated and compared with two existing hybrid *** results showed that the attention model could leverage benefits of PB models and achieved the best predictability of drought events among the different hybrid ***,the ensemble model performed best among all hybrid models at all forecast time scales and different soil *** is highlighted that the ensemble model outperformed the pure DL model over 79.5%of in situ stations for 16-day *** findings suggest that our proposed hybrid models can adequately exploit the benefits of PB model outputs to aid DL models in making SM predictions.

关键词： soil moisture forecasting hybrid model deep learning ConvLSTM attention mechanism