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Broadband isolated attosecond pulse generation in a two-color laser field combined with an orthogonally polarized laser pulse

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 1-6页

作者： DU HongChuan wang xiaoshan HU BiTao School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China

We present a method to generate broadband isolated attosecond pulses. Using a two-color laser field, which is synthesized by a mid-infrared （12.5 fs, 2000 nm） and a weaker （12 fs, 800 nm） pulse in the x direction, a modulated supercontinuum from 290 to 430 eV is obtainable. By properly adding a second-harmonic control field of the driving pulse in the y direction, the short quantum path is well selected and a smooth supercontinuum from 290 to 440 eV is generated. The bandwidth of the supercontinuum can be controlled by adjusting the electric field of the control pulse in the x direction. When the electric field increases to 0.051 a.u., a smooth supercontinuum from 295 to 520 eV is obtained. Using this method we expect that isolated 63-as attosecond pulses with tunable central wavelengths are straightforwardly *** present a method to generate broadband isolated attosecond pulses. Using a two-color laser field, which is synthesized by a mid-infrared （12.5 fs, 2000 nm） and a weaker （12 fs, 800 nm） pulse in the x direction, a modulated supercontinuum from 290 to 430 eV is obtainable. By properly adding a second-harmonic control field of the driving pulse in the y direction, the short quantum path is well selected and a smooth supercontinuum from 290 to 440 eV is generated. The bandwidth of the supercontinuum can be controlled by adjusting the electric field of the control pulse in the x direction. When the electric field increases to 0.051 a.u., a smooth supercontinuum from 295 to 520 eV is obtained. Using this method we expect that isolated 63-as attosecond pulses with tunable central wavelengths are straightforwardly obtained.

关键词： HHG supercontinuum attosecond pulses

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Mercury in leaf litter in typical suburban and urban broadleaf forests in China

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Journal of Environmental Sciences 2011年第12期23卷 2042-2048页

作者： Zhenchuan Niu xiaoshan Zhang Zhangwei wang Zhijia Ci Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons）（（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons）（（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

关键词： mercury broadleaf forests leaf litter soil flux

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Isolated attosecond pulse generation combining propagation effects and a modulated chirped polarization gating technique

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Science China(Physics,Mechanics & Astronomy) 2013年第5期56卷 888-895页

作者： DU HongChuan LUO LaoYong wang xiaoshan HU BiTao School of Nuclear Science and Technology Lanzhou University

We propose a theoretical scheme to generate a broadband supercontinuum using a modulated chirped polarization gating technique. By this technique, a broadband continuum of 155 eV can be obtained at microscopic level. The modulations on the supercontinuum can be eliminated after propagation. Then a smooth broadband supercontinuum with the bandwidth of 155 eV can be generated. As a result, isolated sub-100-attosecond pulses with tunable central wavelengths could be obtained straightforwardly. Our simulations also reveal that an isolated attosecond pulse can still be generated by using multicycle driving laser pulses, and the central wave- length of isolated attosecond pulse can be controlled by adjusting the delay rj （ra is the delay of the two counter-rotating circularly polarized pulses.）.

关键词： HHG supercontinuum attosecond pulse

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Difference between focal mechanisms of Dayao earthquake doublet sequence

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Earthquake Science 2009年第6期22卷 667-673页

作者： xiaoshan wang Xiangdong Feng Guiling Diao Libing wang Lingling Cai Earthquake Administration of Hebei Province Shijiazhuang 050021 China Hongshan Benchmark Seismic Station Longyao 055350 China

Using the maximum amplitude ratios of vertical component of P and S waves recorded by a regional network, 921 focal mechanisms of Dayao earthquake doublet sequence are determined by means of synthetic seismograms of a point source of dislocation in a plane layered medium. Among them, 389 focal mechanisms are in the aftershock sequence of M6.2 earthquake occurred on 21 July, 2003 and the other 532 focal mechanisms are in the aftershock sequence of M6.1 earthquake occurred on 16 October, 2003 in Dayao, Yurman. The focal mechanism consistent parameter a of the two aftershock sequences are calculated and analyzed. According to the focal mechanism consistent parameter a, the focal mechanisms of the first aftershock sequence are more consistent than those of the second. According to the comparison of CMT solutions of the two M6 earthquakes, the physical mechanism of the doublet in the intra-plate earthquake is very complex, and many processes are involved and interacted with each other. This doublet provides insights into earthquake clustering, triggering and stress cycling.

关键词： focal mechanism consistent parameter a Dayao earthquake doublet difference

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Recent Development of Gas Sensing Platforms Based on 2D Atomic Crystals

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Research 2021年第1期2021卷 1445-1482页

作者： Jiacheng Cao Qian Chen xiaoshan wang Qiang Zhang Hai-Dong Yu Xiao Huang Wei Huang Frontiers Science Center for Flexible Electronics Xi’an Institute of Flexible Electronics(IFE)and Xi’an Institute of Biomedical Materials&EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi’an 710072China Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)30 South Puzhu RoadNanjing 211800China

Sensors,capable of detecting trace amounts of gas molecules or volatile organic compounds(VOCs),are in great demand for environmental monitoring,food safety,health diagnostics,and national *** the era of the Internet of Things(IoT)and big data,the requirements on gas sensors,in addition to sensitivity and selectivity,have been increasingly placed on sensor simplicity,room temperature operation,ease for integration,and *** key to meet these requirements is the development of high-performance gas sensing ***-dimensional(2D)atomic crystals,emerged after graphene,have demonstrated a number of attractive properties that are beneficial to gas sensing,such as the versatile and tunable electronic/optoelectronic properties of metal chalcogenides(MCs),the rich surface chemistry and good conductivity of MXenes,and the anisotropic structural and electronic properties of black phosphorus(BP).While most gas sensors based on 2D atomic crystals have been incorporated in the setup of a chemiresistor,field-effect transistor(FET),quartz crystal microbalance(QCM),or optical fiber,their working principles that involve gas adsorption,charge transfer,surface reaction,mass loading,and/or change of the refractive index vary from material to *** the gas-solid interaction and the subsequent signal transduction pathways is essential not only for improving the performance of existing sensing materials but also for searching new and advanced *** this review,we aim to provide an overview of the recent development of gas sensors based on various 2D atomic crystals from both the experimental and theoretical *** will particularly focus on the sensing mechanisms and working principles of the related sensors,as well as approaches to enhance their sensing ***,we summarize the whole article and provide future perspectives for the development of gas sensors with 2D materials.

关键词： Crystal simplicity attractive

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Efficient CO_(2) electroreduction over N-doped hieratically porous carbon derived from petroleum pitch

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Journal of Energy Chemistry 2021年第5期30卷 113-120页

作者： Hui Ning Dianliang Guo xiaoshan wang Zhonghao Tan Wenhang wang Zhongxue Yang Linqing Li Qingshan Zhao Jian Hao Mingbo Wu College of Chemical Engineering College of New EnergyInstitute of New EnergyState Key Laboratory of Heavy Oil ProcessingChina University of Petroleum(East China)Qingdao 266580ShandongChina Stare Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Yinchuan 750021NingxiaChina

Developing of economic and efficient catalysts is critical for the application of electroreduction of carbon dioxide to highly valuable ***,we present a facile method to synthesize N-doped hieratically porous carbon through pyrolysis of petroleum pitch followed by ammonia *** found mesopores are favored formation by removing of asphaltene from petroleum pitch during the carbonation ***,ammonia etching can not only increase the pyridinic-N content,but also upgrade the ratio of meso-to micro-pores of carbon *** the N-doped hieratically porous carbon as catalyst for carbon dioxide electroreduction,the Faradaic efficiency of carbon monoxide reaches 83%at-0.9 V *** reversible hydrogen electrode(RHE)in 0.1 M KHCO_(3).This superior performance is attributed to the synergistic effects of highly pyridinic-N content in conjunction with the hieratically porous architecture,rendering abundant exposed and accessible active sites for electroreduction of CO_(2).Our work provides a new strategy for the large-scale preparation of high-performance,low-cost catalysts for CO_(2) electroreduction.

关键词： Petroleum pitch Carbon dioxide Electroreduction Porous carbon

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Realization of Oriented and Nanoporous Bismuth Chalcogenide Layers via Topochemical Heteroepitaxy for Flexible Gas Sensors

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Research 2022年第4期2022卷 211-221页

作者： Zhiwei wang Jie Dai Jian wang Xinzhe Li Chengjie Pei Yanlei Liu Jiaxu Yan Lin wang Shaozhou Li Hai Li xiaoshan wang Xiao Huang Wei Huang Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)30 South Puzhu RoadNanjing 211816China Frontiers Science Center for Flexible Electronics Xi'an Institute of Flexible Electronics(IFE)and Xi'an Institute of Biomedical Materials EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi'an 710072China Key Laboratory for Organic Electronic e Information Displays(KLOEID)and Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts and Telecommunications9 Wenyuan RoadNanjing 210023China

Most van der Waals two-dimensional(2D)materials without surface dangling bonds show limited surface activities except for their edge *** Bi_(2)Se_(3),a topological insulator that behaves metal-like under ambient conditions,has been overlooked on its surface ***,through a topochemical conversion process,ultrathin nanoporous Bi_(2)Se_(3) layers were epitaxially deposited on BiOCl nanosheets with strong electronic coupling,leading to hybrid electronic states with further bandgap *** oriented nanoporous Bi_(2)Se_(3) layers possessed largely exposed active edge sites,along with improved surface roughness and film forming ability even on inkjet-printed flexible *** room-temperature NO_(2) sensing performance was achieved compared to other 2D materials under bent *** work demonstrates that creating nanoscale features in 2D materials through topochemical heteroepitaxy is promising to achieve both favorable electronic properties and surface activity toward practical applications.

关键词： chemical bonds roughness

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GLOBAL WEAK SOLUTIONS FOR AN ATTRACTION-REPULSION CHEMOTAXIS SYSTEM WITH p-LAPLACIAN DIFFUSION AND LOGISTIC SOURCE

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Acta Mathematica Scientia 2024年第3期44卷 909-924页

作者：王晓闪王忠谦贾哲 Department of Mathematics Luoyang Normal UniversityLuoyang471934China School of Mathematics Science Jiangsu Second Normal UniversityNanjing210013China School of Mathematics and Statistics Linyi UniversityLinyi276005China

This paper is concerned with the following attraction-repulsion chemotaxis system with p-Laplacian diffusion and logistic source:■The system here is under a homogenous Neumann boundary condition in a bounded domainΩ ■ R^(n)(n≥2),with χ,ξ,α,β,γ,δ,k_(1),k_(2)> 0,p> *** addition,the function f is smooth and satisfies that f(s)≤κ-μs~l for all s≥0,with κ ∈ R,μ> 0,l> *** is shown that(ⅰ)if l> max{2k_(1),(2k_(1)n)/(2+n)+1/(p-1)},then system possesses a global bounded weak solution and(ⅱ)if k_(2)> max{2k_(1)-1,(2k_(1)n)/(2+n)+(2-p)/(p-1)} with l> 2,then system possesses a global bounded weak solution.

关键词： global weak solutions attraction-repulsion p-Laplacian logistic source

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Orientation controlled preparation of nanoporous carbon nitride fibers and related composite for gas sensing under ambient conditions

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Nano Research 2017年第5期10卷 1710-1719页

作者： Suqin Li Zhiwei wang xiaoshan wang Fangfang Sun Kai Gao Ningxian Hao Zhipeng Zhang Zhongyuan Ma Hai Li Xiao Huang Wei Huang Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Jiangsu National Synergistic Innovation Centerfor Advanced Materials (SICAM) Nanjing Tech University 30 South Puzhu Road Nanjing 211816 China

Creating pores in suprastructures of two-dimensional （2D） materials while controlling the orientation of the 2D building blocks is important in achieving large specific surface areas and tuning the anisotropic properties of the obtained functional hierarchical structures. In this contribution, we report that arranging graphitic carbon nitride （g-C3N4） nanosheets into one-dimensional （1D） architectures with controlled orientation has been achieved by using 1D oriented melem hydrate fibers as the synthetic precursor via a polycondensation process, during which the removal of water molecules and release of ammonia gas led to the creation of pores without destroying the 1D morphology of the oriented structures. The resulting porous g-C3N4 fibers with both meso- and micro-sized pores and largely exposed edges exhibited good sensing sensitivity and selectivity towards NO2. The sensing performance was further improved by hybridization of the porous fibers with Au nanoparticles （Au NPs）, leading to a detection limit of 60 ppb under ambient conditions. Our results suggest that the highly porous g-C3N4 fibers and the related hybrid structures with largely exposed graphitic layer edges are excellent sensing platforms and may also show promise in other electronic and electrochemical applications.

关键词： graphitic carbon nitride Au nanoparticle gas sensing porous fiber chemiresistive sensor

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Memantine combined with environmental enrichment improves spatial memory and alleviates Alzheimer's disease-like pathology in senescence-accelerated prone-8(SAMP8) mice

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The Journal of Biomedical Research 2012年第6期26卷 439-447页

作者： Jingde Dong Mi Zhou Xiaoqiang Wu Mingyang Du xiaoshan wang Department of Geriatric Neurology Department of Neurology Nanjing Brain Hospital Affiliated to Nanjing Medical UniversityNanjingJiangsu 210029China.

Memantine is a N-methyl-D-aspartate (NMDA) receptor antagonist approved for the treatment of moderate to severe Alzheimer's disease (AD). Environmental enrichment (EE) has shown significant beneficial effects on func- tional improvement in AD. In this study, we sought to determine whether combining these two distinct therapies would yield greater benefit than either drug used alone. We investigated the effect of memantine combined with EE on spatial learning and memory and AD-like pathology in a widely used AD model, the senescence-accelerated prone mice (SAMP8). The SAMP8 mice were randomly assigned to enriched housing (EH) or standard housing (SH), where either memantine (20 mg/kg) or saline was given by gastric lavage once daily continuously for eight weeks. Our results showed that, when provided separately, memantine and EE significantly improved spatial learning and memory by shortening escape latencies and increasing the frequency of entrance into the target quadrant. When combined, memantine and EE showed additive effect on learning and memory as evidenced by significant shorter escape latencies and higher frequency of target entrance than either drug alone. Consistent with the behavior results, pathological studies showed that both memantine and EE significantly reduced hippocampal CA1 neurofibrilliary tangles (NFTs) as well as amyloid beta precursor protein (APP) levels. Combining both therapies synergistically lessened NFTs and APP expression compared to either drug alone in SAMP8 mice, indicating that the combination of memantine with EE could offer a novel and efficient therapeutic strategy for the treatment of AD.

关键词： memantine environmental enrichment SAMP8 mouse spatial memory Alzheimer's disease (AD)

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