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Seasonal variations of leaf wax n-alkane distributions and δ^(2) H values in peat-forming vascular plants from the Dajiuhu peatland, central China

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Frontiers of Earth Science 2022年第3期16卷 774-785页

作者： Jiantao XUE Xueying Zhang Jinzhi LI Zhiqi zhang Huaiying YAO Research Center for Environmental Ecology and Engineering School of Environmental Ecology and Biological EngineeringWuhan Institute of TechnologyWuhan 430073China Administration of Dajiuhu National Wetland Park of Shennongjia Shennongjia 442417China Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

Leaf wax n-alkane compositions have been widely applied to reconstruct paleoclimate histories in peat deposits,yet understanding of how the n-alkanes vary during seasonal plant growth remains limited.Here we report variations in the molecular and wax-derived nalkane hydrogen isotope(δ^(2) Halk)in the three dominant vascular plant species(Sanguisorba officinalis,Carex argyi,Euphorbia esula)and surface peat deposits nearby from the Dajiuhu peatland over a growing season.All three species show a relatively high carbon preference index(CPI)in the beginning of the growing season,with the CPI values reaching as high as 50 in two of the three species.Two species(S.officinalis,E.esula)display relatively stable average chain length(ACL)values over the four sampling intervals,with standard derivations of 0.2-0.3.In contrast,C.argyi exhibits a significant fluctuation of ACL values(averaging 28.11.4)over the growing season.Theδ^(2) Halk in all three species decreased during leaf growth.In the final stage of growth,theδ^(2) Halk values of the three species are similar to those in the surface peats collected from the peatland.Combining the results of our measurements of alkane concentration andδ^(2) H values,it is likely that de novo synthesis of leaf wax n-alkanes in the peatforming plant species is mainly at the early stage of leaf development.In the following months,the removal process exceeds renewal,resulting in a general decrease of the concentration of the total n-alkanes and the integratedδ^(2) Halk values.Thus theδ^(2) Halk values probably integrate the environmental variations at the end of the plant growth period rather than the whole period or the early growth period.These results are significant and have the potential to improve the utility ofδ^(2) Halk values in paleoenvironmental reconstructions.

关键词： peat-forming vascular plants n-alkanes δ^(2)H ratio seasonal variations central China

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Silicalite-1 zeolite encapsulated Fe nanocatalyst for Fenton-like degradation of methylene blue

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Chinese Journal of Chemical Engineering 2023年第1期53卷 251-259页

作者： Hongwei Guo Linyuan Chen Xueying Zhang Huanhao Chen Yan Shao State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China School of Environmental Science and Engineering Nanjing Tech UniversityNanjing 211816China

Encapsulation of Fe nanoparticles in zeolite is a promising way to significantly improve the catalytic activity and stability of Fe-based catalysts during the degradation process of organic pollutants.Herein,Fe nanocatalysts were encapsulated into silicalite-1(S-1)zeolite by using a ligand-protected method(with dicyandiamide(DCD)as a organic ligand)under direct hydrothermal synthesis condition.High-resolution transmission electron microscopy(HRTEM)results confirmed the high dispersion of Fe nanocatalysts which were successfully encapsulated within the voids among the primary particles of the S-1 zeolite.The developed S-1 zeolite encapsulated Fe nanocatalyst(Fe@S-1)exhibited significantly improved catalytic activity and reusability in the catalytic degradation process of methylene blue(MB).Specifically,the developed Fe0.021@S-1 catalyst showed high catalytic degradation activity,giving a high MB degradation efficiency of 100%in 30 min,outperformed the conventional impregnated catalyst(Fe/S-1).Moreover,the Fe@S-1 catalyst afforded an outstanding stability,showing only ca.7.9%activity loss after five cycling tests,while the Fe/S-1 catalyst presented a significantly activity loss of 50.9%after only three cycles.Notably,the encapsulation strategy enabled a relatively lower Fe loading in the Fe@S-1 catalyst in comparison with that of the Fe/S-1 catalyst,i.e.,0.35%vs.0.81%(mass).Radical scavenging experiments along with electron spin resonance(ESR)measurements confirmed that the major role ofOH in the MB degradation process.Specifically,Fe@S-1 catalyst with high molar ratio of[Fe(DCD)]Cl3 is beneficial to form Fe complexes/nanoclusters in the voids(which has large pore size of 1–2 nm)among the primary particles of the zeolite,and thus improving the diffusion and accessibility of reactants to Fe active sites,and thus exhibiting a relatively higher degradation efficiency.This work demonstrates that zeolite-encapsulated Fe nanocatalysts present potential applications in the advanced oxidation of wastewater treatment.

关键词： Zeolite Encapsulation Fe nanocatalyst Degradation Methylene blue

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Silver-catalyzed unstrained C(CO)–alkyl bond scission via[3+2]/retro-[3+2]cycloaddition of ketones with N-isocyanoiminotriphenylphosphorane

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Science China Chemistry 2021年第7期64卷 1157-1163页

作者： Zikun Wang Linxuan Li Xueying Zhang Xihe Bi Department of Chemistry Northeast Normal UniversityChangchun 130024China State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 300071China

C(CO)–alkyl bonds are ubiquitous in a variety of organic molecules,and their selective activation and functionalization are important for the reconstruction of simple ketones into valuable building blocks.However,due to the thermodynamic and kinetic stability,the cleavage and transformation of the unstrained C(CO)–alkyl bonds remain a significant challenge.Herein,we report a novel silver-catalyzed scission of the unstrained C(CO)–alkyl bond of ketones by reacting with N-isocyanoiminotriphenylphosphorane(NIITP)under mild conditions.This method could transform a variety of unstrained ketones into iminophosphoranes and nitriles in high yields.Experimental and computational studies disclosed the reaction proceeded through an unprecedented[3+2]/retro-[3+2]cycloaddition mechanism.

关键词： silver-catalyzed C-C bond scission unstrained ketones tertiary alcohol intermediates cycloaddition

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Perpendicular magnetic anisotropy based spintronics devices in Pt/Co stacks under different hard and flexible substrates

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Science China(Information Sciences) 2023年第2期66卷 256-266页

作者： Sylvain EIMER Houyi CHENG Jinji LI Xueying Zhang Chao ZHAO Weisheng ZHAO Hefei Innovation Research Institute Anhui High Reliability Chips Engineering LaboratoryBeihang University Fert Beijing Institute MIIT Key Laboratory of Spintronics School of Integrated Circuit Science and EngineeringBeihang University School of Physics and Quantum Information Research Center Southeast University Truth Instruments Co.Ltd. Beihang-Geortek Joint Microelectronics Institute Qingdao Research InstituteBeihang University Beijing Superstring Academy of Memory Technology

The magnetic properties in substrate/Pt/Co multilayers, such as perpendicular magnetic anisotropy(PMA), are of particular interest for spintronic devices. In particular, it is important to obtain a strong PMA on the flexible substrate in the field of wearable devices and structural health monitoring.However, the different stacks deposition and regulation conditions on the magnetic properties of the films lack systematic research. Here, we investigate the magnetic properties in Pt/Co structures with different hard and flexible substrates, layer thicknesses, and the different deposition temperatures of the buffer layer.We found that the coercive field and magnetodynamic behavior of the films change with these factors. Moreover, depositing the buffer layer under high temperature can effectively adjust the crystalline state of the films, thus affecting the performance of the films. After depositing the buffer layer at 800℃, our films can obtain a better crystalline state and PMA. The measurement results of the magneto-optical Kerr microscope show that the magnetic domain wall motion of the films can be controlled by different substrate and buffer layer conditions. It was expected that ultra-fast magnetic moment switching can be achieved by optimizing the conditions to reduce the power consumption of the device. The experimental results also show that the optimized film conditions can also obtain strong PMA on the flexible substrate. These findings help to understand magnetic properties in these structures and show the promising prospect for wearable devices and other spintronic devices.

关键词： Pt/Co stacks perpendicular magnetic anisotropy magnetodynamic behavior spintronics flexible devices high temperature deposition

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Current advances of biocontainment strategy in synthetic biology

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Chinese Journal of Chemical Engineering 2023年第4期56卷 141-151页

作者： xueying Zhu Zhaoyang zhang Bin Jia Yingjin Yuan Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Synthetic biotechnology has led to the widespread application of genetically modified organisms(GMOs)in biochemistry, bioenergy, and therapy. However, the uncontrolled spread of GMOs may lead to genetic contamination by horizontal gene transfer, resulting in unpredictable biosafety risks. To deal with these challenges, many effective methods have been developed for biocontainment. In this article, we summarize and discuss recent advances in biocontainment strategies from three aspects: DNA replication, transcriptional regulation, and protein translation. We also briefly introduce the efforts in the biocontainment convention, such as the recent publication of the Tianjin Biosecurity Guidelines for the Code of Conduct for Scientists.

关键词： Genetically modified organisms(GMOs) Biocontainment Biosecurity Synthetic biology Molecular biology Biotechnology

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Fecal microbiota transplantation: standardization or diversification?

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Science China(Life Sciences) 2019年第12期62卷 1714-1716页

作者： Xueying Zhang Hongliang Tian Qiyi Chen Huanlong Qin Ning Li Intestinal Microenvironment Treatment Center Shanghai Tenth People’s Hospital Tongji University School of Medicine

Call for standardization of fecal microbiota transplantation(FMT)The gut microbiota plays an important role in human health and disease.Dysbiosis is often recognized in patients with diseases of the digestive and other systems(Blaser,2019;Li et al.,2018b;Qin et al.,2018).FMT refers to the administration of fecal material containing distal gut microbiota from a healthy person(donor)to a patient(recipient)to restore the gut microecology of the recipient(Kelly et al.,2015).Clinical guidelines have strongly recommended FMT for the treatment of relapsed or refractory Clostridium difficile infection(CDI)(Mullish et al.,2018).FMT has also shown potential clinical benefits in many other diseases related to dysbiosis,including inflammatory bowel disease(IBD),irritable bowel syndrome(IBS),functional constipation(FC),liver diseases,metabolic syndrome,autism,and cancer(Huang et al.,2018;Li et al.,2018a;zhang et al.,2018).Because of its broad curative potential,FMT has become a topic of great interest.More than 3,000 published articles have reported treatment of different diseases with FMT,and over 380 FMT trials have been registered on the ClinicalTrials.gov website.

关键词： donor standardization registered

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Cyclic constitutive equations of rock with coupled damage induced by compaction and cracking

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International Journal of Mining Science and Technology 2022年第5期32卷 1153-1165页

作者： Chonghong Ren Jin Yu xueying Liu Zhuqing zhang Yanyan Cai Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen 361021China Xiamen Rail Transit Group Corporation Limited Xiamen 361021China

In this paper,the cyclic constitutive equations were proposed to describe the constitutive behavior of cyclic loading and unloading.Firstly,a coupled damage variable was derived,which contains two parts,i.e.,the compaction-induced damage and the cracking-induced damage.The compaction-induced damage variable was derived from a nonlinear stress–strain relation of the initial compaction stage,and the cracking-induced damage variable was established based on the statistical damage theory.Secondly,based on the total damage variable,a damage constitutive equation was proposed to describe the constitutive relation of rock under the monotonic uniaxial compression conditions,whereafter,the application of this model is extended to cyclic loading and unloading conditions.To validate the proposed monotonic and cyclic constitutive equations,a series of mechanical tests for marble specimens were carried out,which contained the monotonic uniaxial compression(MUC)experiment,cyclic uniaxial compression experiments under the variable amplitude(CUC-VA)and constant amplitude(CUC-CA)conditions.The results show that the proposed total damage variable comprehensively reflects the damage evolution characteristic,i.e.,the damage variable firstly decreases,then increases no matter under the conditions of MUC,CUC-VA or CUC-CA.Then a reasonable consistency is observed between the experimental and theoretical curves.The proposed cyclic constitutive equations can simulate the whole cyclic loading and unloading behaviors,such as the initial compaction,the strain hardening and the strain softening.Furthermore,the shapes of the theoretical curves are controlled by the modified coefficient,compaction sensitivity coefficient and two Weibull distributed parameters.

关键词： Cyclic constitutive equations Rock Coupled damage Compaction Cracking

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Spatial-temporal Analysis of Emotions in Society in News

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Journal of Geodesy and Geoinformation Science 2022年第2期5卷 98-110页

作者： An HUAI Xueying Zhang Weicheng AI Tianyang CAO Key Laboratory of Virtual Geographic Environment Ministry of EducationNanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Spatial-temporal analysis of emotions in society has become popular in many studies integrating geography with the humanities,and has shown its influence on social sensing and geo-computation for social sciences.Emotions in society are often volatile,irrational,and vulnerable to the social environment.A critical challenge is to analyze changes in long-term and large-scale emotions in society.In this paper,we propose exploiting this challenge by using spatial-temporal analysis.After extracting emotional,temporal,and spatial information,a spatial standardization approach based on adataset of administrative district changes addresses the problem of Chinese toponym changes.Finally,over 1.7 million news data from the People’s Daily from 1956 to 2014 were collected to explore the changes,spatial distribution,and driving factors of emotions in society using spatial-temporal analysis.The experimental results found that the spatial-temporal analysis of emotions in society in the news is consistent with the results of related sociological research.

关键词： spatial-temporal analysis emotional change newsdata social sensing long-term and large-scale emotion

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Spintronics intelligent devices

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 17-43页

作者： Wenlong Cai Yan Huang Xueying Zhang Shihong Wang Yuanhao Pan Jialiang Yin Kewen Shi Weisheng Zhao Fert Beijing Institute MIIT Key Laboratory of SpintronicsSchool of Integrated Circuit Science and EngineeringBeihang UniversityBeijing100191China Beihang-Goertek Joint Microelectronics Institute Qingdao Research InstituteBeihang UniversityQingdao266000China

Intelligent computing paradigms have become increasingly important for the efficient processing of massive amounts of data.However,using traditional electronic devices to implement these intelligent paradigms is currently mismatched and limited by their energy,area,and speed.Spintronics,which exploits the magnetic and electrical properties of electrons,could break through these limitations and bring new possibilities to electrical devices.In particular,the tunneling magnetoresistance effect,merging quantum and spintronics,enables spintronic devices to be compatible with standard integrated circuits with a magnetic tunnel junction(MTJ)design,showing great potential for implementing hardware-based intelligent frameworks.In this review,we introduce the specific capabilities of MTJs,including nonvolatility,stochasticity,plasticity,and nonlinearity,which are highly favorable in artificial intelligence algorithms.We then present how these devices could impact the development of intelligent computing,including in-memory computing,probabilistic computing,and neuromorphic computing.Finally,we discuss their challenges and perspectives in intelligent hardware implementations.

关键词： tunneling magnetoresistance effect magnetic tunnel junction in-memory computing probabilistic computing neuromorphic computing

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Research on microwave radiation features and lunar regolith parameters inversion of the Rümker region

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Science China Earth Sciences 2021年第6期64卷 1005-1014页

作者： xueying WANG Zhenzhan WANG Jingshan JIANG Dehai zhang Key Laboratory of Microwave Remote Sensing National Space Science CenterChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

Chang'e-5(CE-5)mission is expected to land and sample in the Rümker region,north of the Oceanus Procellarum.To select optimal sampling points,the microwave radiation features in this mare unit are analyzed,and the dielectric constant and thickness of lunar regolith are retrieved based on Chang'e lunar microwave sounder(CELMS)data.According to the microwave brightness temperature(TB)maps,TB varying with frequency at noon and midnight are different,in which noon TB increases with frequency,but midnight TB does not follow this rule.Moreover,there are differences among TB distributions at the three higher frequencies,especially in the southern part.In addition,a great TB difference between noon and midnight can be seen in Rümker E that shows higher daytime temperature but lower nighttime temperature.The inversion results reveal that the dielectric constant is lower in the west and north,higher in the middle and east,and the largest value occurs in Rümker E.As for the regolith thickness,most areas are uniform and no more than 4 m,with the thickest and thinnest regolith appearing in the northwest and Rümker E,no less than 6 m and about 2.5 m,respectively.Considering the safety and operability of landing and sampling,the northwest with thick regolith is recommended,while the Rümker E should be eluded.

关键词： Rümker region Microwave sounder Brightness temperature Lunar regolith dielectric constant Lunar regolith thickness

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