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Al-containing Ge-rich IWV:rapid synthesis via interzeolite transformation and application in Baeyer-Villiger oxidation

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Science China Chemistry 2024年第7期67卷 2282-2291页

作者： Meichen jiao Chunmin Jia Hao Xu Peng Wu Xian-Ming Zhang School of Chemistry&Material Science Shanxi Normal UniversityTaiyuan 030006China Shanghai key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China School of Chemistry Taiyuan University of TechnologyTaiyuan 030024China

Ge-containing Lewis acidic zeolites are typically synthesized using a conventional hydrothermal strategy from amorphous silica sources,through a long time-and energy-consuming approach limiting their wide *** study reports a rapid synthesis strategy for a series of IWV aluminogermanosilicate zeolites(T-x-Al)with a wide range of Si/Ge molar ratios(5–15)by interzeolite transformation of dealuminated FAU(DA-FAU).Notably,Ge-rich IWV could be obtained with crystallization time as short as one day by the equimolecular Si/Ge ratio *** effect of synthetic parameters was investigated and the obtained T-x-Al samples were characterized by XRD,SEM,EDS,ICP,^(29)Si and^(27)Al MAS NMR,FTIR,and N_(2)physisorption *** with a previously reported IWV germanosilicate(H-3),T-x-Al displayed a better catalytic activity in Baeyer-Villiger(BV)oxidation,attributed to the presence of the active framework Ge sites with the assistance of the extraframework Al *** cyclic catalysis tests revealed that the presence of framework Al species contributed to the stability of the ***,T-x-Al,with 14-membered ring(MR)supercages,outperformed the typical 12-MR Sn-beta catalyst in the BV oxidation of large ketone-like 2-admantanone,indicating a promising potential application in the macromolecular catalytic process.

关键词： Ge-rich IWV interzeolite transformation Al assistance Baeyer-Villiger oxidation

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基于传播树的多特征谣言检测方法

电子学报 2024年第5期52卷 1609-1618页

作者：张鑫昕潘善亮茅琴娇宁波大学信息科学与工程学院浙江宁波315211 宁波工程学院网络空间安全学院浙江宁波315211

目前网络谣言的检测方法主要是从传播路径中寻找信息,大多只采用文本信息作为初始传播特征,因此难以捕捉到丰富的传播结构表示.本文根据谣言的传播路径,提取文本和用户可信度特征,构建一种基于传播树的多特征谣言检测模型.模型通过图卷... 详细信息

目前网络谣言的检测方法主要是从传播路径中寻找信息,大多只采用文本信息作为初始传播特征,因此难以捕捉到丰富的传播结构表示.本文根据谣言的传播路径,提取文本和用户可信度特征,构建一种基于传播树的多特征谣言检测模型.模型通过图卷积网络聚合文本传播信息,使用多头注意力机制挖掘文本传播树的层内依赖关系,同时对用户传播树中的每个用户构建可信度序列,并采用M-Attention模块捕获有效的用户可信度特征.实验结果表明,本文提出的方法在Twitter15、Twitter16和Weibo数据集上的检测准确率达到89.3%、91.7%和96.4%,相比当前最优的传播树模型Bi-GCN(Binary Graph Convolutional Network)分别提升4.8%、4.2%和3%.

关键词：谣言检测传播结构图卷积网络注意力机制自然语言处理

Electron vortex generations in photoionization of hydrogen atoms by circularly-polarized chirped attosecond pulses

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Communications in Theoretical Physics 2024年第1期76卷 111-118页

作者： Bingshuang Zhang Xiaoyu Liu Fengzheng Zhu Liguang jiao Aihua Liu Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China College of Physics Jilin UniversityChangchun 130012China Helmholtz-Institut Jena D-07743 JenaGermany State key Laboratory of Transient Optics and Photonics Chinese Academy of SciencesXi'an 710119China

By numerically solving the time-dependent Schr?dinger equation and employing the analytical perturbative model,we investigated the chirp-induced electron vortex in the photoionization of hydrogen atoms by a pair of counter-rotating circularly polarized chirped attosecond extremely ultraviolet *** demonstrated that single-photon ionization of hydrogen atoms generates photoelectron momentum distributions(PMDs)with distinct helical vortex structures either with or without a time delay between two counter-rotating circularly polarized laser *** structures are highly sensitive to both the time delay between the pulses and their chirp *** analytical model reveals that the splitting of vortex spirals is caused by the sign changing of the chirp-induced frequency-dependent time *** showed that to obtain the counterpart of the PMD under a pair of counter-rotating circularly polarized chirped pulses,both chirp parameters and ordering of pulses need to be reversed.

关键词： photoionization ultrafast processes ultrafast dynamics electron vortex

Soil type and wetting intensity control the enhancement extent of N_(2)O efflux in soil with drought and rewetting cycles

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International Soil and Water Conservation Research 2024年第1期12卷 137-144页

作者： Panpan jiao Lei Yang Zhongwu Li Peng Zheng Xiaodong Nie School of Geographical Sciences Hunan Normal UniversityChangsha 410081China State key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau The Research Center of Soil and Water Conservation and Ecological EnvironmentChinese Academy of Sciences and Ministry of EducationYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China University of Chinese Academy of Sciences Beijing 100049China key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Climate change alters the intensity and frequency of drought and rewetting(D/W)events;however,the influence patterns of D/W on soil N_(2)O efflux in the water-limited area were not fully ***,the impacts of D/W cycles varying in different extent of rewetting and frequency to N_(2)O efflux in two kinds of soil on the Loess Plateau were *** incubation conditions consisted of 1)D/W treatments with four 7-day cycles from 10%water holding capacity(WHC)to 60%WHC or 90%WHC,2)constant moisture of 60%WHC and 90%*** pulse of N_(2)O efflux rate under 10-60%WHC treatment was higher than that under 10-90%WHC treatment in calcic cambisols,while opposite trend was observed in earth-cumuli-orthic ***,the pulse of N_(2)O efflux rate decreased as cycle number increased for different wetting intensities and soil *** direct N_(2)O efflux under 10-60%WHC and 10-90%WHC treatments were 5.49 and 1.89μg N_(2)O-N g^(-1)soil in calcic cambisols,with those being 1.92 and 10.85μg N_(2)O-N g^(-1)soil in earth-cumuli-orthic anthrosols,*** N loss in earth-cumuli-orthic anthrosols was approximately 5.74 times greater than that in calcic cambisols under 10-90%WHC treatment,whereas the N loss under 10-60%WHC treatment was about 2.86 times greater in calcic cambisols than that in earth-cumuli-orthic *** study suggested that extreme rainfall events can enhance the N_(2)O efflux and N loss in agricultural soils on the Loess Plateau in terms of soil type and wetting intensity,which should not be ignored in the N fertilizer management.

关键词： Drought/rewetting cycles N_(2)O efflux Wetting intensity Microbial biomass N Dissolved organic N Loess plateau

Synergistic enhancement of Ce-ZnO/g-C_(3)N_(4)photocatalytic performance using N,O-bis-vacancy induction and S-scheme heterojunctions

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Journal of Rare Earths 2024年第5期42卷 817-826,I0001页

作者： Guyu Zhang Yuan Zhang xinlei Zhao Yujiang jiao Yumin Yan Jianhui Jiang Engineering Laboratory of Chemical Resources Utilization in South xinjiang of xinjiang Production and Construction Corps College of Chemistry a Chemical EngineeringTarimUniversityAlar843300China

The photocatalytic decontamination of organic pollutants is an environmentally friendly and efficient water treatment *** introduction of vacancies,heterojunctions,and doping can enhance the performance of photocatalysts for such *** this study,N,O double-vacancy Ce-ZnO/g-C_(3)N_(4)S-scheme heterojunction photocatalysts were prepared,It is found that the electron separation and transfer efficiencies are considerably improved by the presence of nitrogen vacancies in graphitic ca rbon nitride(g-C_(3)N_(4))and oxygen vacancies in ZnO,in addition to the S-scheme heterojunction created between the two *** the degradation of methylene blue and ciprofloxacin,the degradation rates exhibited by Ce-ZnO/g-C_(3)N_(4)are significantly higher than those of the g=C_(3)N_(4)/ZnO *** remarkable photocatalytic performance of Ce-ZnO/g-C_(3)N_(4)may result from three key factors;(ⅰ)Ce doping,which produces impurity energy levels;(ⅱ)the generation of electron capture centres by the N and O vacancies;and(ⅲ)the synergistic effect of the S-type heterojunction formed at the interface between the two materials,This study therefore provides new approaches for the use of doping,vacancies,and heterojunctions to induce the efficient degradation of organic pollutants.

关键词： Photocatalysis Vacancy S-scheme Ce-ZnO/g-C_(3)N_(4) Degradation Rare earths

Hydrochemical Characteristics and Evolution of Underground Brine in Lop Nur,Northwestern China

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 786-800页

作者： BO Ying LIU Chenglin jiao Pengcheng LU Fenglin ZHANG Hua MNR key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

Lop Nur is located at the eastmost end of the Tarim Basin in xinjiang,Northwestern *** study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur,based on analytical data from 429 water samples(mainly brine).It is found that in the NE-SW direction,from the periphery to the Luobei sub-depression,while the hydrochemical type varies from the sodium sulfate subtype(S)to the magnesium sulfate subtype(M),the corresponding brine in the phase diagram transfers from the thenardite phase(Then)area,through the bloedite phase(Blo),epsomite phase(Eps),picromerite phase(Picro),finally reaching the sylvite phase(Syl)*** for the degree of evolution,the sequence is the peripheryke's *** on chemical compositions of brine from drillhole LDK01 and previous lithological studies,the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration-dilution periods.

关键词： brine evolution isotope enrichment potassium Lop Nur

Theoretical screening of cooperative N-bridged dual-atom sites for efficient electrocatalytic nitrogen reduction with remolding insight

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Nano Research 2024年第4期17卷 3413-3422页

作者： Huimei Chen Yan Yang Chi jiao Zhiwen Zhuo Junjie Mao Yan Liu key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China

The electrocatalytic nitrogen reduction reaction(e-NRR)is a promising alternative method for the Haber–Bosch ***,it still faces many challenges in searching for high activity,stability,and selectivity catalysts and ascertaining the catalytic mechanism with complete ***,a series of graphene-based N-bridged dual-atom catalysts(M1-N-M2/NC)are systematically investigated via first-principle calculation and a high-throughput screening *** result unveils that N_(2) adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts(SACs).Moreover,V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts,with extremely low limiting potentials of-0.20 and-0.18 V,***,the adsorption site competition between*N_(2) and*H,as well as the competitive twin reactions of hydrogen evolution reaction(HER)on intermediates(N_(n)H_(m))during the e-NRR process,is systematically evaluated to form a remodeling insight for the reactions in mechanism,and the e-NRR of new proposed dual-atom catalysts(DACs)is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR *** work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

关键词： nitrogen reduction dual-atom catalysts high-throughput screening hydrogen evolution reaction density functional theory calculations

Inner-shell ionization cross sections of atoms by positron impact

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Communications in Theoretical Physics 2024年第6期76卷 142-147页

作者： Yuan-Cheng Wang Jia Ma Li-Guang jiao Stephan Fritzsche College of Physical Science and Technology Shenyang Normal UniversityShenyang 110034China Helmholtz-Institut Jena D-07743 JenaGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH D-64291 DarmstadtGermany College of Science Shenyang Aerospace UniversityShenyang 110136China College of Physics Jilin UniversityChangchun 130012China Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena07743 JenaGermany

The relativistic binary-encounter-Bethe model with Wannier-type threshold law is employed to obtain the inner-shell ionization cross sections of multi-electron atoms(Ni,Cu,Y,Ag,Au,Yb,Ta,and Pb)for positron impact energies from the thresholds up to 105ke *** is good agreement between the present calculations and the experimental *** constant in the acceleration term derived from the Wannier law is determined to be 0.2 and 0.5 for the K-and L-shells,respectively.

关键词： positron scattering ionization cross section binary-encounter-Bethe model

Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land,Northwest China

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Pedosphere 2024年第1期34卷 63-77页

作者： Yanwu PEI Laiming HUANG Ming'an SHAO jiao WANG Yinglong ZHANG Yellow River Delta Modern Agricultural Engineering Laboratory Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Natural Resources and Environment Northwest Agriculture and Forestry UniversityYangling 712100China State key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences of Chinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Shenmu Ecological Association Shenmu 719399China

Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen(δ^(2)H) and oxygen(δ^(18)O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species(Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content(SWC), the soil water profile of the three species stands was divided into active(0.01 g g^(-1)45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep(59.2%±9.7%, moist layer and groundwater),intermediate(57.4%±9.8%, stable and moist layers), and shallow(54.4%±10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early(June) dry season;then, they switched to the active and stable layers in the rainy season(July–September) for water resources(50.1%–62.5%). In the late(October–November) dry season, P. sylvestris(54.5%–66.2%) and A. pedunculata(52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila(52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant pheno

关键词： desert ecosystem MixSIAR model plant water uptake soil moisture stable isotopes vegetation restoration water-use efficiency