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BOUNDARY ELEMENT APPROXIMATION OF STEKLOV EIGENVALUE PROBLEM FOR HELMHOLTz EQUATION

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Journal of Computational Mathematics 1998年第2期16卷 165-178页

作者： Tang, WJ guan, z Han, HD Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China Tsing Hua Univ Dept Appl Math Beijing 100084 Peoples R China

Steklov eigenvalue problem of Helmholtz equation is considered in the present paper. Steklov eigenvalue problem is reduced to a new variational formula on the boundary of a given domain, in which the self-adjoint property of the original differential operator is kept and the calculating of hyper-singular integral is avoided. A numerical example showing the efficiency of this method and an optimal error estimate are given.

关键词： Steklov eigenvalue problem differential operator error estimate boundary element approximation

DYNAMIC STRAIN AGING BEHAVIOR OF K40S ALLOY

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Acta Metallurgica Sinica(English Letters) 2003年第6期16卷 473-477页

作者： F.M. Yang, X.F. Sun, H.R. guan and z.Q. HuInstitute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016, China Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016 China

The dynamic strain aging behavior during tensile tests of K40S alloy has been investigated in the temperature range of 25-1100℃ with the strain rate range from 10-4 to 10-3s-1. The results show that four different types of serration, identified as A, B, C and E type serration were observed in the temperature range of 300-600℃. The strain exponents for onset of the serrated flow were calculated as 1.21, 2.19 and 1.61, and the activation energies as 121, 40 and 67kJ/mol for E, B and C type serration respectively. The main mechanism for dynamic strain aging discussed in light of the strain exponent and the activation energy.

关键词： dynamic strain aging serrated flow strain exponent activation energy

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小动脉征：T4a结肠癌分期的影像学特征

国际医学放射学杂志 2024年第2期 250-250页

作者： z.guan z.W.Li D.Yang T.Yu H.J.Jiang X.Y.zhang 束宏敏

摘要目的通过分析现有和新提出的pT1-3和pT4a期肿瘤的影像学特征分布，寻找一个显著特征并验证其诊断效能。方法回顾性收集2016年1月—2017年12月共3个中

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The stress-thermal equivalence“memory effect”in glass materials

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 175-176页

作者： Pengfei guan Beijing Computational Science Research Center Beijing 100193China

Glass materials,including metallic,organic,and silicate glasses,are crucial in various engineering applications due to their unique disordered atomic packing ***,these materials suffer from stress decay under constant... 详细信息

关键词： glasses glass stress

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A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： Wei WEI Feng guan Xin FANG College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate

Brain Mechanisms Underlying Panic Attack and Panic Disorder

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Neuroscience Bulletin 2024年第6期40卷 795-814页

作者： Xuyan guan Peng Cao Tsinghua Institute of Multidisciplinary Biomedical Research Tsinghua UniversityBeijing102206China National Institute of Biological Sciences(NIBS) Beijing102206China

Panic disorder is a psychiatric disorder characterized by recurrent panic attacks,with a prevalence of~4%in the general population,causing heavy personal and socioeconomic *** similarities of animal defense responses to clinical panic attack symptoms in humans make it possible to translate neuroanatomical pathways identified in animal studies to panic disorder in ***,in this review we first present a basic overview of panic disorder in humans including the main subtypes,models commonly used to trigger panic attacks,related hypotheses,the neurotransmitter systems that may be involved,and the current clinical treatments to give the reader a comprehensive understanding of panic *** animal section introduces the models that trigger panic-like behavior in animals and the brain regions that may be involved,providing insights for future elucidation of the neural circuit mechanisms behind panic attacks.

关键词： Panic disorder Panic attack Defense responses Animal studies Humans

3D Localization for Multiple AUVs in Anchor-Free Environments by Exploring the Use of Depth Information

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1051-1053页

作者： Yichen Li Wenbin Yu Xinping guan the Department of Automation Shanghai Jiao Tong UniversityShanghai 200240 the Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai Jiao Tong UniversityShanghai 200240China

Dear Editor,This letter investigates the cooperative localization problem for multiple autonomous underwater vehicles(AUVs)in underwater anchor-free environments,where AUV localization errors grow without bound due to the accumulated errors in inertial measurements(termed accumulated errors hereafter)and the lack of anchors(with known positions).

关键词： AUVs underwater hereafter

Proactive Resilience Enhancement of Power Systems with Link Transmission Model-based Dynamic Traffic Assignment Among Electric Vehicles

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1320-1330页

作者： Haoyuan Yan Tianyang zhao zhanglei guan Energy Electricity Research Center Jinan UniversityGuangzhou 510632China Energy Research Institute Nanyang Technological UniversitySingapore IEEE

The rapid development of electric vehicles(EVs)is strengthening the bi-directional interactions between electric power networks(EPNs)and transportation networks(TNs)while providing opportunities to enhance the resilience of power systems towards extreme *** quantify the temporal and spatial flexibility of EVs for charging and discharging,a novel dynamic traffic assignment(DTA)problem is *** DTA problem is based on a link transmission model(LTM)with extended charging links,depicting the interaction between EVs and power *** models the charging rates as continuous variables by an energy boundary *** consider the evacuation requirements of TNs and the uncertainties of traffic conditions,the DTA problem is extended to a two-stage distributionally robust *** is further incorporated into a two-stage distributionally robust unit commitment problem to balance the enhancement of EPNs and the performance of *** problem is reformulated into a mixed-integer linear programming problem and solved by off-the-shelf commercial *** studies are performed on two test *** effectiveness is verified by the numerical results,e.g.,reducing the load shedding amount without increasing the unmet traffic demand.

关键词： Coupled transportation and power network link transmission model resilience enhancement

Reduced magma generation and its implications for the Pulang giant porphyry Cu-polymetallic deposit in Northwest Yunnan,China

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Acta Geochimica 2024年第4期43卷 802-813页

作者： Jingwei guan Tao Ren Lei Wang Shenjin guan Lianrong Wu Baosheng Shi Faculty of Land Resources Engineering Kunming University of Science and TechnologyKunming 650093People’s Republic of China Diqing Nonferrous Metals Co. LtdShangri-La 674400People’s Republic of China

The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the zhongdian area in the center of the Sanjiang Tethys tectonic domain,which was formed by the westward subduction of the Garze-Litang oceanic slab beneath the zhongza ***-pyrrhotite-pyritemolybdenite occurs as disseminations,veins,veinlets,and stockworks distributed in the K-silicate alteration zone in the monzonite porphyry,which is superimposed by *** chemical compositions of biotite and amphibole analyzed by electron probe microanalysis(EPMA)indicate that the ore-forming magma and exsolved fluids experienced a continuous decrease in the oxygen fugacity(fO_(2)).Primary amphibolite and biotite(type I)crystallized at relatively high temperatures(744-827°C)and low fO_(2)(log fO_(2)=−12.26 to−11.91)during the magmatic *** fluids exsolved from the magma have a relatively lower temperature(621-711°C)and fO_(2)(log fO_(2)=−14.36 to−13.32)than the original *** addition,the presence of a high abundance of pyrrhotite and an insufficiency of primary magnetite and sulfate in the ore(i.e.,anhydrite and gypsum)indicate that the deposit may be a reduced porphyry *** and fluid fO_(2)results,combined with previous research on magmatic fO_(2)at the Pulang deposit,indicate that the magma associated with the reduced Pulang ore assemblages was initially generated as a highly oxidized magma that was subsequently reduced by sedimentary rocks of the Tumugou Formation.

关键词： Porphyry deposit Oxygen fugacity(fO_(2)) Contamination of surrounding rock Pulang zhongdian arc