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Journal of Environmental Sciences 2020年第10期32卷 55-63页

作者： xin xing Na Li jie Cheng Yonggang Sun Zhongshen Zhang xin Zhang Zhengping Hao Key Laboratory of Environmental Nanotechnology and Health Effects Research Center for Eco-Enuironmental SciencesChinese Academy of SciencesBeijing 100085China National Engineering Laboratory/or VOCs Pollution Control Material&Technology Research Center/or Environmental Material and Pollution Control TechnologyUniversity of Chinese Academy of SciencesBeijing 101408China

In this work, a series of Cu-ZSM-5 catalysts with different SiO2/Al2O3 ratios(25, 50, 100 and200) were synthesized and investigated in n-butylamine catalytic degradation. The n-butylamine can be completely catalytic degradation at 350 ℃ over all Cu-ZSM-5 catalysts. Moreover, Cu-ZSM-5(25) exhibited the highest selectivity to N2, exceeding 90% at 350 ℃. These samples were investigated in detail by several characterizations to illuminate the dependence of the catalytic performance on redox properties, Cu species, and acidity. The characterization results proved that the redox properties and chemisorption oxygen primarily affect n-butylamine conversion. N2 selectivity was impacted by the Bronsted acidity and the isolated Cu^2+ species. Meanwhile, the surface acid sites over Cu-ZSM-5 catalysts could influence the formation of Cu species. Furthermore, in situ diffuse reflectance infrared Fourier transform spectra was adopted to explore the reaction mechanism. The Cu-ZSM-5 catalysts are the most prospective catalysts for nitrogen-containing volatile organic compounds removal, and the results in this study could provide new insights into catalysts design for VOC catalytic oxidation.

关键词： CH3CH2CH2CH2NH2 Selective oxidation Cu-ZSM-5 Cu species Acid sites

Mobile Edge Communications, Computing, and Caching(MEC3) Technology in the Maritime Communication Network

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China Communications 2020年第5期17卷 223-234页

作者： jie Zeng Jiaying Sun Binwei Wu xin Su Chongqing University of Posts and Telecommunications Chongqing 400065China Tsinghua University 100084BeijingChina University of Electronic Science and Technology of China Chengdu 610054China

With the increasing maritime activities and the rapidly developing maritime economy, the fifth-generation(5G) mobile communication system is expected to be deployed at the ocean. New technologies need to be explored to meet the requirements of ultra-reliable and low latency communications(URLLC) in the maritime communication network(MCN). Mobile edge computing(MEC) can achieve high energy efficiency in MCN at the cost of suffering from high control plane latency and low reliability. In terms of this issue, the mobile edge communications, computing, and caching(MEC3) technology is proposed to sink mobile computing, network control, and storage to the edge of the network. New methods that enable resource-efficient configurations and reduce redundant data transmissions can enable the reliable implementation of computing-intension and latency-sensitive applications. The key technologies of MEC3 to enable URLLC are analyzed and optimized in MCN. The best response-based offloading algorithm(BROA) is adopted to optimize task offloading. The simulation results show that the task latency can be decreased by 26.5’ ms, and the energy consumption in terminal users can be reduced to 66.6%.

关键词： best response-based offloading algorithm(BROA) energy consumption mobile edge computing(MEC) mobile edge communications,computing,and caching(MEC3) task offloading

Dramatic sediment load changes and sedimentation characteristics upstream of the Three Gorges Dam due to the large reservoirs construction

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Frontiers of Earth Science 2024年第3期18卷 565-578页

作者： jie LIU Wenwu ZHANG Ying SHEN xin WANG National Inland Waterway Regulation Engineering Research Center Chongqing Jiaotong UniversityChongqing 400074China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China School of River&Ocean Engineering Chongqing Jiaotong UniversityChongqing 400074China Tianjin Research Institute for Water Transport Engineering Tianjin 300456China

After the construction of cascade reservoirs in the upper reaches of the Three Gorges Reservoir(TGR),the sediment load outflow of the upper Yangtze River Basin(YRB)has been significantly altered,decreasing from 491.8 Mt/yr(1956–2002)to 36.1 Mt/yr(2003–2017)at Yichang *** has widely affected river hydrology,suspended sediment grain size distribution,and channel *** study analyzed hydrological variations in water discharge and sediment load of the upper YRB over the past 62 years(1956–2017)by employing a double mass *** variations in the source areas of sediment yielding for the upper YRB were quantified,and field measurement data of the cross-channel profile were collected to investigate the sedimentation process in the TGR from 2003 to *** than 90%of the sediment load reduction in the upper YRB may be explained by human *** Jinshajiang River was no longer the largest sediment source area for the Zhutuo station(accounting for 5.23%)in the 2013–2017 time span,and the sediment rating rates for the inflow and outflow of the TGR shifted to negatively correlated.A longitudinal fining trend was revealed in the suspended sediment ***,the mean median grain size of suspended sediment in the TGR had an increasing trend in the 2013–2017 *** result may be closely related to sediment regulation in reservoirs and incoming sediment load *** in the TGR decreased sharply from 299.8 Mt/yr in 2003–2012 to 47.2 Mt/yr in 2013–2017,but the sedimentation rate of the TGR remained at>80%***,some cross sections in the fluctuating backwater zone experienced scouring.

关键词： cascade reservoirs sediment load sedimentation characteristics suspended sediment grain size Three Gorges Reservoir

Effects of upper mantle wind on mantle plume morphology and hotspot track:Numerical modeling

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Science China Earth Sciences 2024年第12期67卷 3881-3899页

作者： jie xin Huai ZHANG Yaolin SHI Felipe ORELLANA-ROVIROSA College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of SciencesBeijing 101408China

A mantle thermal plume may be tilted,deflected,or even split-up by mantle lateral flows(mantle wind)during its ascent,which in turn changes the spatial distribution of various geological-magmatic responses,such as magmatic activity in the overriding plate and hotspot tracks on the surface,affecting the reliability of the constraints on absolute plate motion *** research on tilted mantle plumes has focused mainly on the lower/whole mantle *** mantle plumes formed in whole/layered mantle convection suffer lateral tilt in the upper mantle,and how this affects the magmatic activity along the surface hotspot track as well as the plume-related tectonic processes,are important scientific issues in mantle thermalplume dynamics and plate tectonics *** study introduces a thermal Stokes-fluid-dynamics numerical model(in ASPECT software)and pyrolite parameters constrained by mineral physics data,and quantitatively analyzes the tilted/deflected morphology of upper-mantle plumes and the concomitant surface-hotspot location-evolution characteristics under the combined effects of overriding-plate-motion driven flow(Couette)and upper mantle counter-flow(Poiseuille).We find that this composite upper-mantle wind can lead to(1)Plume head-and-upper-conduit horizontal motion in the opposite direction of the overriding plate motion and also with respect to the conduit roots,such that the magmatic spacing is increased;(2)Near-periodic split-up and ascent of a laterally-moving plume conduit,whose split-up/ascent period depends mainly on the thermo-chemical buoyancy of the plume itself;and(3)Under specific conditions of thermo-chemical buoyancy of a main“parent”plume interacting with upper mantle winds,two secondary“child”plumes hundreds of kilometers apart can sprout and ascend sequentially/subsimultaneously through the upper mantle in a very short period of time(2–4 Myr).The resulting oscillating/jumping behavior of hotspot locations along the overriding pl

关键词： Hotspot track Mantle plume Upper mantle wind Absolute plate motion Plume-derived magmatism Numerical modeling

Influence of topography,soil properties and plant community on the biomass of Abies georgei *** seedlings in Southeast Tibet

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Journal of Mountain Science 2022年第9期19卷 2664-2677页

作者： ZHANG xin-sheng ZHOU Chen-ni LU jie Institute of Tibet Plateau Ecology Tibet Agricultural&Animal Husbandry UniversityNyingchi 860000China Key Laboratory of Forest Ecology in Tibet Plateau Tibet Agricultural&Animal Husbandry UniversityMinistry of EducationNyingchi 860000China Linzhi National Forest Ecosystem Observation&Research Station of Tibet Nyingchi 860000China Key Laboratory of Alpine Vegetation Ecological Security in Tibet Nyingchi 86000China

Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site *** objectives of this study was to explore the distribution characteristics of AGB(above-ground biomass)and BGB(below-ground biomass)of Abies georgei *** seedlings of different ages,and investigate the effects of topography(slope aspect,altitude),plant community characteristics(crown density,species diversity,etc.),and soil properties(soil physical and chemical properties)on the biomass and its *** in five age classes(1–2,3–4,5–6,7–8,and 9–10 years old)were collected by full excavation from 6 elevations(3800 m,3900 m,4000 m,4100 m,4200 m,4300 m)on the north and south slopes of Sejila Mountain in Tibet.15seedlings of each age class were investigated at one *** individual effects of seedling age(SA)and the interaction effects of SA,slope aspect(SL),and elevation(EG),namely,SL×EG,SL×SA,EG×SA,and SL×EG×SA,had significant effects on the AGB of the seedlings(p<0.05),whereas BGB was only significantly affected by SA(p<0.001).The AGB and BGB of the seedlings showed a binomial growth trend with the increase in seedling age,and had an allometric relationship at different elevations,α(allometric exponential)varied from 0.913 to 1.046 in the northern slope,and from 1.004 to 1.268 in the southern *** biomass of seedlings on the northern slope was remarkably affected by stand factors,with a contribution rate of 47.8%,whereas that on the southern slope was considerably affected by soil factors with a contribution rate of 53.2%.The results showed that age was the most important factor affecting seedling *** allometric pattern of seedling biomass was relatively stable,but in a highaltitude habitat,*** *** seedlings increased the input of *** seedling biomass allocation and its influencing factors is useful for evaluating plants’ability to acquire resources and surviv

关键词： Biomass allocation Allometric relationship Stand characteristic Soil factors Abies georgei var.smithii seedlings Sejila Mountain,Tibet

An adaptive large neighborhood search for the multi-point dynamic aggregation problem

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Control Theory and Technology 2024年第3期22卷 360-378页

作者： Shengyu Lu Bin xin jie Chen Miao Guo School of Automation Beijing Institute of TechnologyBeijing 100081China National Key Lab of Autonomous Intelligent Unmanned Systems Beijing 100081China Department of Control Science and Engineering Tongji UniversityShanghai 201804China

The multi-point dynamic aggregation(MPDA)problem is a challenging real-world *** the MPDA problem,the demands of tasks keep changing with their inherent incremental rates,while a heterogeneous robot fleet is required to travel between these tasks to change the time-varying state of each *** robots are allowed to collaborate on the same task or work separately until all tasks are *** is challenging to generate an effective task execution plan due to the tight coupling between robots abilities and tasks'incremental rates,and the complexity of robot *** effectiveness consideration,we use the variable length encoding to avoid redundancy in the solution *** creatively use the adaptive large neighborhood search(ALNS)framework to solve the MPDA *** the proposed algorithm,high-quality initial solutions are generated through multiple problem-specific solution construction *** heuristics are also used to fix the broken solution in the novel integrated decoding-construction repair process of the ALNS *** results of statistical analysis by the Wilcoxon rank-sum test demonstrate that the proposed ALNS can obtain better task execution plans than some state-of-the-art algorithms in most MPDA instances.

关键词： Adaptive large neighborhood search(ALNS) Multi-point dynamic aggregation(MPDA) Heuristic solution construction Multi-robot collaboration

The equilibrium stability for a smooth and discontinuous oscillator with dry friction

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Acta Mechanica Sinica 2016年第2期32卷 309-319页

作者： Zhi-xin Li Qing-jie Cao Alain Léger School of Astronautics Centre for Nonlinear Dynamics Research Harbin Institute of Technology Harbin 150001 China Laboratoire de Mecanique et d' Acoustique CNRS 31 Chemin Joseph Aiguier 13402 Marseille Cedex 20 France

In this paper,we investigate the equilibrium stability of a Filippov-type system having multiple stick regions based upon a smooth and discontinuous（SD） oscillator with dry *** sets of equilibrium states of the system are analyzed together with Coulomb friction conditions in both（ f_n,f_s） and（x,˙x） *** the stability analysis,Lyapunov functions are constructed to derive the instability for the equilibrium set of the hyperbolic type and La Salle＇s invariance principle is employed to obtain the stability of the nonhyperbolic *** demonstrates the existence of a thick stable manifold and the interior stability of the hyperbolic equilibrium set due to the attractive sliding mode of the Filippov property,and also shows that the unstable manifolds of the hyperbolic-type are that of the endpoints with their saddle *** calculations show a good agreement with the theoretical analysis and an excellent efficien y of the approach for equilibrium states in this particular Filippov ***,the equilibrium bifurcations are presented to demonstrate the transition between the smooth and the discontinuous regimes.

关键词： SD oscillator Equilibrium set Dry friction Coulomb’s cone

Quantum anomalous hall effect in collinear antiferromagnetism

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npj Computational Materials 2023年第1期9卷 1655-1660页

作者： Peng-jie Guo Zheng-xin Liu Zhong-Yi Lu Department of physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices Renmin University of China100872 BeijingChina

The two-dimensional Quantum Hall effect with no external magnetic field is called the Quantum anomalous Hall (QAH) effect. Sofar, experimentally realized QAH insulators all exhibit ferromagnetic order and the QAH effect only occurs at very low *** the other hand, up to now the QAH effect in collinear antiferromagnetic (AFM) materials has never been reported and thecorresponding mechanism has never been proposed. In this work, we realize the QAH effect by proposing a four-band lattice modelwith static AFM order, which indicates that the QAH effect can be found in AFM materials. Then, as a prototype, we demonstratethat a monolayer CrO can be switched from an AFM Weyl semimetal to an AFM QAH insulator by applying strain, based onsymmetry analysis and the first-principles electronic structure calculations. Our work not only proposes a scenario to search for QAHinsulators in materials, but also reveals a way to considerably increase the critical temperature of the QAH phase.

关键词： materials effect effect

Automatic recognition of intersecting features of freeform sheet metal parts

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1439-1449页

作者： Chun-jie ZHANG Xiong-hui ZHOU Cong-xin LI National Die and Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

This paper presents an approach for recognizing both isolated and intersecting geometric features of freeform surface models of parts,for the purpose of automating the process planning of sheet metal *** developed methodology has three major steps:subdivision of B-spline surfaces,detection of protrusions and depressions,and recognition of geometric features for sheet metal forming *** input geometry data format of the part is based on an IGES CAD surface model represented in the form of trimmed B-spline *** surface is classified or subdivided into different curvature regions with the aid of curvature property surfaces obtained by using symbolic computation of B-spline *** regions satisfying a particular geometry and topology relation are recognized as protrusion and depression(DP) *** DP shapes are then classified into different geometric features using a rule-based approach.A verified feasibility study of the developed method is also presented.

关键词： Feature recognition (FR) Freeform surface Feature intersection Sheet metal forming

Bridging peripheral nerves using a deacetyl chitin conduit combined with short-term electrical stimulation

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Neural Regeneration Research 2014年第10期9卷 1075-1078页

作者： Zhongli Zhang xin Li Songjie Zuo jie xin Peixun Zhang Department of Traumatic Orthopedics Weifang People’s Hospital Department of Physiology Weifang Medical College National Institute for Radiological Protection Chinese Center for Disease Prevention and Control Department of Trauma&Orthopedics Peking University People’s Hospital

Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation （0.1 ms, 3 V, 20 Hz, for 1 hour）. At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, ifber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimu-lation can promote peripheral nerve repair.

关键词： nerve regeneration peripheral nerve injury deacetyl chitin conduit electrical stimulation NSFC grant neural regeneration