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Thermal stability of permafrost under U-shaped crushed rock embankment of the qinghai-Tibet Railway

Advances in Climate Change Research 2024年第1期15卷 158-169页

作者： Kun-ming XU Guan-Li JIANG Ji CHEN qing-Bai wu State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Beiluhe Observation Station of Frozen Soil Environment and Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China

The U-shaped crushed rock embankment(UCRE),of which widely utilized in the permafrost regions along the qinghai-Tibet Railway,has the capability to rapidly reduce the ground temperature of the underlying ***,there remains uncertainty regarding the adaptation of UCRE to climate change and its long-term cooling *** study focuses on nine UCRE monitoring sites along the qinghai-Tibet Railway to analyze the dynamic variations of the ground temperature underlying permafrost from 2006 to *** efficiency of UCRE in stabilizing permafrost temperature in different permafrost zones is evaluated by considering the permafrost table,ground temperature,and MAGT,as well as the temperature difference between the top and bottom of the crushed rock layer and the ground temperature variation index(GTVI).The results show that UCRE is suitable for application in extremely unstable warm permafrost regions where the MAGT is higher than-0.5℃.Moreover,UCRE effectively diminishes the disparity in permafrost thermal stability between the sunny and shaded shoulders of the *** short-term and long-term effect of cooling permafrost is experiencing a change related with permafrost ***,in stable cold permafrost regions with MAGT lower than-1.5℃,the long-term cooling effect of UCRE on permafrost seems to gradually di-minishes,but UCRE continues to fulfill the role of stabilizing the underlying permafrost thermal state over the *** results show that UCRE can quickly restore and stabilize the thermal state of permafrost in the early stages of construction,and adapt to the influence of future climate *** findings provide important guidance for understanding the variations of permafrost thermal stability beneath the embankment in permafrost regions,as well as for improving the embankment stability and operational safety of the qinghai-Tibet Railway.

关键词： qinghai-Tibet Railway U-shaped crushed rock embankment Climate change Permafrost zone Ground temperature variation index Long-term coolingrole

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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

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Warming intensified the effects of nitrogen addition on N_(2)O emissions from alpine meadow in the northern qinghai-Tibet Plateau

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Advances in Climate Change Research 2024年第1期15卷 101-112页

作者： ming-Jie LI Yi-qing GE Hasbagan GANJURJAV Guo-Zheng HU Hong-Bao wu Jun YAN Shi-Cheng HE qing-Zhu GAO Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081China National Agricultural Experimental Station for Agricultural Environment Nagqu 852100China Ecology and Nature Conservation Institute Chinese Academy of ForestryBeijing 100091China College of Resource and Environment Anhui Science and Technology UniversityFengyang 233100China Nagqu Agriculture Animal Husbandryand Prataculture Science and Technology Research and Extension CenterNagqu 852100China Tongliao Experimental Middle School Tongliao 028000China

Warming and nitrogen(N)addition may impact soil nitrous oxide(N_(2)O)emissions,but the relationship between plant community composition and soil microbial activities remains *** a two-year field study in the qinghai-Tibet Plateau,open-top chambers were used to quantify the effects of warming,N-addition,and their interactions on N_(2)O *** found that the N-addition greatly increased N_(2)O emissions by 77.4%in 2018 when compared to the control *** contrast,warming showed little effect on N_(2)0 emissions but did increase the activity of enzymes associated with soil nitrification and denitrification.A combined effect of warming and N-addition of resulted in 208.6%(2018)and 90.8%(2019)increase in N_(2)0 emissions,respectively,compared to the individual treatments of warming or *** warming in alpine meadows is causally linked to increased legume biomass which is further intensified with the *** legume biomass(pming further intensifies this *** increased dominance of legumes and microbial N content contributes to this *** outcomes suggest that warming and atmospheric N deposition can stimulate N_(2)O emissions of alpine meadows inthefuture.

关键词： Alpine meadow Community composition Nitrogen addition Nitrous oxide flux qinghai-Tibet Plateau Warming

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Formal Modeling and Verification of Carrier-borne Aircraft Ammunition Support Operation Scheduling

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Ruan Jian Xue Bao/Journal of Software 2024年第9期35卷

作者： Jin, Zhao Jin, Lu Zhang, Bo-Wen wu, qing-Shun Feng, Shuo Li, Guan-Feng Xu, ming-Liang School of Computer and Artificial Intelligence Zhengzhou University Zhengzhou 450001 China Engineering Research Center of Intelligent Swarm Systems Ministry of Education Zhengzhou 450001 China National Supercomputing Center in Zhengzhou Zhengzhou 450001 China Beijing Institute of Astronautical Systems Engineering Beijing 100076 China The 713 Research Institute of China Shipbuilding Industry Corporation Zhengzhou 450015 China

As an efficient scheduling method, the intelligent planning of ammunition support operation of carrier-borne air craft is an important way to boost the development of advanced technology of aircraft carrier engineering. Ensuring the correctness of operation planning schemes under the high safety-critical attribute has gradually become the key technical bottleneck restricting the security of their practical application deployments. Aiming at the challenges posed by the difficulties in modeling ammunition support systems, describing operation execution behavior, and realizing formal verification tools, this study proposes a behavior model for ammunition support systems based on the separation logic idea, where the theorem prover Coq is employed to conduct formal verification on the operation planning scheme. First, a serialized two-tier resource heap model that conforms to the characteristics of ammunition support operation is proposed. Subsequently, a set of modeling language and operational semantics are constructed based on this model to describe job execution behavior. Finally, a proof assistant tool is implemented in Coq. The usability and engineering practicability of the tool are verified by interactive demonstrations of several typical ammunition support operation planning schemes. © 2024 Chinese Academy of Sciences. All rights reserved.

关键词： Aircraft

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The Role of Renewable Protocatechol Acid in Epoxy Coating Modification: Significantly Improved Antibacterial and Adhesive Properties

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Chinese Journal of Polymer Science 2024年第1期42卷 63-72,I0008页

作者： ming-Xuan Chen Jin-Yue Dai Li-Yue Zhang Shuai-Peng Wang Jing-Kai Liu Yong-Gang wu Xin-wu Ba Xiao-qing Liu School of Chemistry and Materials Science Hebei UniversityBaoding 071000China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China Key Laboratory of Marine Materials and Related Technologies Chinese Academy of SciencesNingbo 315201China

It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.

关键词： Epoxy coatings Thermosets Catechol structure Antibacterial High adhesion

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Numerical Study on Local Flow and Heat Transfer Characteristics of Supercritical CO_(2) in PCHE with Sinusoidal Channels

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Journal of Thermal Science 2024年第1期33卷 41-55页

作者： WENZhexi LV Yigao LI qing wu Jinglin School of Energy Science and Engineering Central South UniversityChangsha 410083China

Local heat transfer and flow characteristics,which is crucial to the overall performance of supercritical CO_(2) recuperators,is rarely examined in details in reported *** this paper,the local heat transfer and flow characteristics of supercritical CO_(2) in sinusoidal channel printed circuit heat exchangers are numerically investigated under the working conditions of *** on the simplified physical model constituted by10 pitches,the variations of Re,heat flux,Nu,secondary flow and other relevant parameters along the flow direction are analyzed *** is further made between the high and low temperature recuperators(HTR and LTR).It's observed that the local heat transfer and flow characteristics vary greatly from the inlet to the outlet,especially in the *** of 127.5% and 61.7% can be observed on the cold side of the LTR for Re and heat transfer coefficient h, *** indicate that the temperature difference and heat transfer coefficient h should not be regarded as constant and the distribution of h should be carefully considered in the design of the *** complicated interactions among the varying thermophysical properties,buoyancy and the periodically changed centrifugal force are believed to be the key that shapes the flow ***,the changes of the wavy angle θ are found to have greater influence than the changes of mass flow rate in reshaping the flow field when θ>25°.Though gravity direction strongly affects the local heat transfer and flow characteristics,it's also found that the effects on the overall thermal-hydraulic performance are relatively *** the installation direction that yields a_y=g should better be avoided for the sinusoidal channel printed circuit heat exchanger.

关键词： printed circuit heat exchanger supercritical CO_(2) sinusoidal channel heat transfer recuperator

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Enhanced hydrogen evolution reaction in FePt film with remanence due to decrease in domain walls

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Rare Metals 2024年第3期43卷 1108-1115页

作者： Hong Hong Dong-Xue Liu Jun Li Jun-ming Li Li-Qian wu Bo Yang qing-Qi Cao Dun-Hui Wang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresJiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing210093China Hangzhou Dianzi University Hangzhou310018China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China

As an effective strategy to improve the properties of electrocatalysts,magnetic field-assisted electrocatalytic water splitting has attracted increasing attention ***,the corresponding enhancements mostly depend on the exertion of an external magnetic field during electrochemical reactions,which results in a high cost of industrial production,and makes the magnetic field manipulation of electrocatalysis become a challenging *** this work,instead of the external magnetic field,a bias magnetic field is self-supplied by the remanence state of a ferromagnetic electrocatalyst of *** to the assistance of this bias magnetic field,the FePt film in the remanence state shows the overpotential of 229 mV during hydrogen evolution reaction,which is much lower than that in its demagnetization state(283 mV).Our findings demonstrate that the remanence in ferromagnetic electrocatalysts can improve the catalytic performance,which is attributed to the decrease in domain walls.

关键词： Remanence Magnetic domains Electrocatalysis Hydrogen evolution reaction(HER)

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Classification of complete 3-dimensional self-shrinkers in the Euclidean space R^(4)

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Science China Mathematics 2024年第4期67卷 873-882页

作者： qing-ming Cheng Zhi Li Guoxin Wei Department of Applied Mathematics Faculty of ScienceFukuoka UniversityFukuoka 814-0180Japan College of Mathematics and Information Science Henan Normal UniversityXinxiang 453007China School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China

In this paper,we completely classify 3-dimensional complete self-shrinkers with the constant norm S of the second fundamental form and the constant f3in the Euclidean space R^(4),where hij’s are components of the sec... 详细信息

关键词： mean curvature ow self-shrinker the generalized maximum principle

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Nest site selection of white-naped crane(Grus vipio) at Zhalong National Nature Reserve, Heilongjiang, China

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Journal of Forestry Research 2014年第4期25卷 947-952页

作者： qing-ming wu Hong-fei ZOU Jian-zhang MA College of Wildlife Resource Northeast Forestry University

White-naped crane （Grus vipio） is a globally threatened spe- cies. It is very important to analyze its nest site selection in circum- stances where there are multiple disturbances, and also helpful to accu- mulate valuable information about this threatened species and supply scientific suggestions for conservation and management. We studied nest site selection and the effects of environmental variables on nesting habits of white-naped crane at Zhalong National Nature Reserve, Qiqihar City, Heilongiiang, China, during March-May of 2002-2008. White-naped crane responded and adapted to changes in the quality of the spatial environments of landscape and microhabitat under multiple environ- mental disturbances. Nest site selection included two scales and two choices, namely the choice of nest site habitat type within the macro-habitat scale and nest site micro-habitat selection within the mi- cro-habitat scale. Nest sites were recorded only in reed marshes. The choice of nest site micro-habitat included three basic elements and six factors, namely incubation element （nest parameters factor, incubation temperature factor and incubation humidity factor）, safety element （pro- tection factor and concealment factor）, and food element （water factor）. Water, remnant reed clusters, and fire were major resource management challenges during the breeding period for the white-naped crane in this Reserve.

关键词： factor analysis environmental variable Grus vipio nestsite selection pattern Zhalong Nature Reserve

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Communication Resource-Efficient Vehicle Platooning Control With Various Spacing Policies

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 362-376页

作者： Xiaohua Ge qing-Long Han Xian-ming Zhang Derui Ding IEEE School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourne VIC 3122Australia

Platooning represents one of the key features that connected automated vehicles may possess as it allows multiple automated vehicles to be maneuvered cooperatively with small headways on roads. However, a critical challenge in accomplishing automated vehicle platoons is to deal with the effects of intermittent and sporadic vehicle-to-vehicle data transmissions caused by limited wireless communication resources. This paper addresses the co-design problem of dynamic event-triggered communication scheduling and cooperative adaptive cruise control for a convoy of automated vehicles with diverse spacing policies. The central aim is to achieve automated vehicle platooning under various gap references with desired platoon stability and spacing performance requirements, while simultaneously improving communication efficiency. Toward this aim, a dynamic event-triggered scheduling mechanism is developed such that the intervehicle data transmissions are scheduled dynamically and efficiently over time. Then, a tractable co-design criterion on the existence of both the admissible event-driven cooperative adaptive cruise control law and the desired scheduling mechanism is derived. Finally, comparative simulation results are presented to substantiate the effectiveness and merits of the obtained results.

关键词： Automated vehicles constant time headway spacing constant spacing cooperative adaptive cruise control event-triggered communication vehicle platooning

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