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时间域航空电磁法在多年冻土调查研究中的应用

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物探与化探 2024年第2期48卷 342-347页

作者：余学中谢汝宽单希鹏何怡原孙思源李诗珺中国自然资源航空物探遥感中心北京100083 自然资源部航空地球物理与遥感地质重点实验室北京100083

多年冻土空间分布调查在冰冻圈研究中具有重要意义。目前国内冻土空间分布调查通常采用地面物探结合测井的探测方法,获得局部点上或线上数据,或者采用不同的遥感模型,模拟估算区域性多年冻土厚度。笔者利用获取的时间域航空电磁数据,根... 详细信息

多年冻土空间分布调查在冰冻圈研究中具有重要意义。目前国内冻土空间分布调查通常采用地面物探结合测井的探测方法,获得局部点上或线上数据,或者采用不同的遥感模型,模拟估算区域性多年冻土厚度。笔者利用获取的时间域航空电磁数据,根据电阻率计算结果推断多年冻土空间分布特征。推断结果与已知测井资料对比分析表明,根据时间域航空电磁数据反演结果推断的多年冻土层厚度与已知测井测温确定的结果平均误差为18.5%,表明采用时间域航空电磁法开展多年冻土厚度调查是有效的,具有较高的准确性。由于时间域航空电磁测量具有高效、受地形影响小等技术优势,可应用于青藏高原、东北大兴安岭等地区的大面积、快速、定量化的多年冻土调查,为全面调查研究多年冻土空间分布及其对生态环境变化的影响提供新的、有效的技术解决方案。

关键词：多年冻土时间域航空电磁法青藏高原

Rapid Unconscious Acquisition of Conditioned Fear with Low-Spatial-Frequency but Emotionally Neutral Stimuli

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Research 2024年第1期2023卷 753-762页

作者： Yujie Chen si Chen Zhongju sun Xilei Zhang Xiangyong yuan Liang Wang Yi Jiang State Key Laboratory of Brain and Cognitive Sciences CAS Center for Excellence in Brain Science and Intelligence TechnologyInstitute of PsychologyChinese Academy of SciencesBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 100049China Chinese Institute for Brain Research Beijing 102206China CAS Key Laboratory of Mental Health Institute of PsychologyChinese Academy of SciencesBeijing 100101China

It has long been proposed that emotionally“prepared”(i.e.,fear-related)stimuli are privileged in the unconscious acquisition of conditioned ***,as fear processing is suggested to highly depend on the coarse,low-spatial-frequency(LSF)components of the fear-related stimuli,it is plausible that LSF may play a unique role in the unconscious fear conditioning even with emotionally neutral ***,we provided empirical evidence that,following classical fear conditioning,an invisible,emotionally neutral conditioned stimulus(CS+)with LSF,but not with high spatial frequency(HSF),can rapidly elicit stronger skin conductance responses(SCRs)and larger pupil diameters than its CS−*** comparison,consciously perceived emotionally neutral CS+with LSF and HSF elicited comparable *** together,these results support that the unconscious fear conditioning does not necessarily entail emotionally prepared stimuli but prioritizes LSF information processing and highlight the crucial distinctions between the unconscious and the conscious fear *** findings not only coincide with the postulation that a rapid,spatial-frequency-dependent subcortical route is engaged in unconscious fear processing but also suggest the existence of multiple routes for conscious fear processing.

关键词： neutral necessarily diameters

Malvidin Mitigates Sepsis-induced Cardiac Injury by Modulating the TLR4-iNOS-COX-2 Inflammatory Pathway and the Bax/Bcl-2/Cyto-C Mitochondrial Apoptosis Pathway in a p38 MAPK-dependent Manner

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Biomedical and Environmental Sciences 2024年第2期37卷 221-227页

作者： ZHANG Wei yuan si Long QIANG Jing Chao HUANG He LI Da sun Ying ZHANG Hong Gang Department of Vascular Surgery The First People’s Hospital of LianyungangLianyungang 222005JiangsuChina Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening College of PharmacyJiangsu Ocean UniversityLianyungang 222005JiangsuChina Jinzhou Medical University postgraduate training base(Lianyungang First People’s Hospital) Lianyungang 222005JiangsuChina

In critical care medicine,sepsis is a dangerous systemic condition that is highly prevalent and is associated with high morbidity and mortality rates^([1]).The high mortality rate associated with sepsis is closely related to multi-organ dysfunction,with heart injury being particularly critical and considered the starting point of multi-organ injury^([2]).

关键词： mortality Apoptosis TLR4

Pyrolysis Empirical Modeling of Polyester Glass Fiber Reinforced Plastics Using Sestak-Berggren Model Method

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Journal of Thermal Science 2024年第2期33卷 725-738页

作者： NAN Wei JI Wenhui yuan Yanping yuan Zhongyuan sun Yong School of Mechanical Engineering Southwest Jiaotong UniversityChengdu610031China CRRC Changchun Railway Vehicles Co. LtdChangchun130062China

Polyester Glass Fiber Reinforced Plastic(Polyester GFRP),a thermosetting plastic comprised of glass fiber and polyester polymer compounds,is extensively utilized in high-speed *** its pyrolysis mechanism is crucial as it significantly influences the combustion characteristics and fire safety ***,kinetic research on polyester GFRP primarily focuses on employing the Coats-Redfern method to derive a theoretical kinetic ***,the pyrolysis process of polyester GFRP is complex and the aforementioned theoretical model fails to accurately describe the pyrolysis ***,this study seeks to utilize the Sestak and Berggren(SB) model as a methodological approach to reveal the complex reaction mechanism during the pyrolysis *** on thermogravimetric analysis,the entire pyrolysis process of polyester GFRP is divided into two primary ***,model-free methods are employed to ascertain the activation energy and pre-exponential *** results show that the fitted empirical models of the two main pyrolysis stages are f(α)=(1-α)^(1.47)[-ln(1-α)]^(1.50) and f(α)=(1-α)^(1.77)[-ln(1-α)]^(1.72),*** predicted results are in good agreement with experimental data under different heating rates,which indicates that the empirical model can sufficiently describe the pyrolysis process of polyester GFRP.

关键词： polyester GFRP model-fitting methods empirical models pyrolysis

Global Zero-relaxation Limit Problem of the Electro-diffusion Model Arising in Electro-Hydrodynamics

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Acta Mathematicae Applicatae sinica 2024年第1期40卷 241-268页

作者： Ming-hua Yang si-ming Huang Jin-yi sun Department of Mathematics Jiangxi University of Finance and EconomicsNanchang330032China School of Public Administration Guangdong University of Foreign StudiesGuangzhou510006China College of Mathematics and Statistics Northwest Normal UniversityLanzhou730070China

In this paper,we study a global zero-relaxation limit problem of the electro-diffusion model arising in electro-hydrodynamics which is the coupled Planck-Nernst-Poisson and Navier-Stokes *** is,the paper deals with a singular limit problem of{u^(∈)_(t)+u^(∈)·▽u^(∈)-Δu^(∈)+▽P^(∈)=Δφ^(∈)▽φ^(∈),in R^(3)×(0,∞),▽·u^(∈)=0,in R^(3)×(0,∞),n^(∈)_(t)+u^(∈)·▽n^(∈)-Δn^(∈)=-▽·(n^(∈)▽φ^(∈)),in R^(3)×(0,∞),ct+u^(∈)·▽c^(∈)-Δc^(∈)=▽·(c^(∈)▽φ^(∈)),in R^(3)×(0,∞),∈^(-1)φ^(∈)_(t)=Δφ^(∈)-n^(∈)+c^(∈),in R^(3)×(0,∞),(u^(∈),n^(∈),c^(∈),φ^(∈))|t=0=(u0,n0,c0,φ0),in R^(3) involving with a positive,large parameter^(∈).The present work show a case that(u^(∈),n^(∈),c^(∈))stabilizes to(u^(∞),n∞,c∞):=(u,n,c)uniformly with respect to the time variable as^(∈)→+∞with respect to the strong topology in a certain Fourier-Herz space.

关键词： fourier-Herz space littlewood-Paley decomposition stability limit dissipative system

Implication of community-level ecophysiological parameterization to modelling ecosystem productivity:a case study across nine contrasting forest sites in eastern China

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Journal of Forestry Research 2024年第1期35卷 1-11页

作者： Minzhe Fang Changjin Cheng Nianpeng He Guoxin si Osbert Jianxin sun School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China Research Institute of Energy Saving Environmental ProtectionOccupational Safety and HealthChina Academy of Railway Sciences Corporation LimitedBeijing 100081China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Parameterization is a critical step in modelling ecosystem ***,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations often arise from inappropriate model *** we compared five methods for defining community-level specific leaf area(SLA)and leaf C:N across nine contrasting forest sites along the North-South Transect of Eastern China,including biomass-weighted average for the entire plant community(AP_BW)and four simplified selective sampling(biomass-weighted average over five dominant tree species[5DT_BW],basal area weighted average over five dominant tree species[5DT_AW],biomass-weighted average over all tree species[AT_BW]and basal area weighted average over all tree species[AT_AW]).We found that the default values for SLA and leaf C:N embedded in the Biome-BGC v4.2 were higher than the five computational methods produced across the nine sites,with deviations ranging from 28.0 to 73.3%.In addition,there were only slight deviations(simplified selective sampling methods,and no significant difference between the predictions of AT_BW and AP_BW except the Shennongjia *** findings in this study highlights the critical importance of computational strategies for community-level parameterization in ecosystem process modelling,and will support the choice of parameterization methods.

关键词： Biome-BGC Community traits Forest Ecosystems Model parameterization

Flower-like CuS/γ-Fe_(2)O_(3) van der Waals heterostructures with highefficient electromagnetic wave absorption

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Nano Research 2024年第4期17卷 3324-3333页

作者： Na Lu Jingshen Xu Mengwei yuan Genban sun Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

The escalating electromagnetic(EM)pollution issues and the demand to elevate military stealth technology make it imperative to develop cost-effective and high-performance electromagnetic wave(EMW)absorbing *** this paper,the flower-like CuS/γ-Fe_(2)O_(3) van der Waals(vdW)heterostructures have been synthesized via a facile two-step solvothermal *** flower-like CuS skeleton increases the attenuation path of EMW while reducing the material *** contents ofγ-Fe_(2)O_(3) nanoparticles anchor between the flower-like CuS nanosheets to constitute a heterogeneous structure,which enables dielectric and magnetic loss synergistically to optimize impedance matching and remarkably improve the EMW absorption *** minimum reflection loss(RLmin)is-49.36 dB with a thickness of only 1.6 mm and the effective absorption bandwidth(EAB)reaches 4.64 GHz(13.36–18 GHz).By adjusting the thickness of the absorber,the EAB can cover 96%of the GHz ***,the superior absorption of-61.53 dB at middle frequency band can be obtained by adjusting the amount of Fe_(2)O_(3) *** this study,the adjustment of EM parameters and the optimization of impedance matching have been achieved by constructing a novel vdW heterogeneous structure,which provides fresh ideas and references for the design of high-performance EMW absorbing materials.

关键词： flower-like CuS γ-Fe_(2)O_(3) van der Waals heterostructures impedance matching electromagnetic wave absorption

Influence of calendering process on the structural mechanics and heat transfer characteristics of lithium-ion battery electrodes via DEM simulations

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Particuology 2024年第2期85卷 252-267页

作者： Junpeng Zhang Jingna sun Huagui Huang Zhenge yuan National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004China Xingtai Naknor Technology Co. LtdXingtai054000China

Elucidating the intricate correlation between calendering,structure,and performance is crucial to comprehending the relationship between performance parameters and process steps of lithium-ion batteries(LIBs).Discrete element method(DEM)simulations were adopted in this work to calculate the interparticle force and stress tensor under incremental calendering process conditions,which revealed the effect of the anisotropy of complex contact force network on the anisotropy of heat transfer within porous *** thermal conductivity of electrode was predicted using porosity to characterize the process-structure-performance *** comprehensive influence of contact number and con-tact area between particles and current collector determines the magnitude of interfacial thermal resistance and interfacial heat transfer *** the first time,this work quantitatively analyzed the structural mechanics and heat transfer mechanism during calendering process of porous electrodes,and the results indicate a promising way to optimize and design battery electrode structures.

关键词： Li-ion battery electrode Structural mechanicsAnisotropy Thermal conductivity Discrete element method

Synthesis of multifunctional additives for solid propellants:Structure,properties and mechanism

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Defence Technology（防务技术） 2024年第3期33卷 308-316页

作者： Pingan Zhang Lina sun Jianmin yuan Jianru Deng College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082PR China College of Material Science and Engineering Hunan UniversityChangsha 410082PR China Hu Bei Sanjiang Aerospace Jianghe Chemical Technology Co. LtdYichang 444200PR China

To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB by adopting appropriate synthesis *** replacing 10% of HTPB binder in the propellant formulation,it can effectively enhance the interfacial bond strength between the propellant binder matrix and solid fillers(AP(ammonium perchlorate)and RDX(cyclotrimethylene-trinitramine)),the mechanical properties of the HTPB/AP/RDX/Al propellant were superior to blank control propellant with an improvement of 35.4% in tensile strength,62.0% enhancement in elongation at break,and reduce the propellant burn rate by 10.7% with any energy *** function mechanism of AEHTPB-CN was systematically elucidated through experiments and computer simulation *** results show that the tertiary amine group in AEHTPB-CN can react with AP to form ammonium ionic bonds,and the hydroxyl and cyano groups can form hydrogen bonding interactions with AP,which enables AEHTPB-CN to be firmly adsorbed on the AP surface through chemical and physical *** RDX,the interfacial bonding effect of AEHTPB-CN is attributed to their ability to form C-H···N≡C weak hydrogen bonding interaction between the cyano group and RDX methylene group.

关键词： Hydroxyl-terminated polybutadiene(HTPB) HTPB propellant Chemical modification Bonding agent Mechanism