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LONG-TERM CREEP ASSESSMENT OF VISCOELASTIC POLYMER BY TIME-TEMPERATURE-STRESS SUPERPOSITION

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Acta Mechanica Solida Sinica 2012年第6期25卷 571-578页

作者： wenbo luo Chuhong Wang Xiaoling Hu Tingqing Yang College of Civil Engineering and Mechanics Xiangtan University Department of Mechanics Huazhong University of Science and Technology

Nonlinear viscoelastic creep properties of poly （methyl methacrylate） at various temperatures and stress levels were measured in short-term tests to check the applicability of time-temperature-stress superposition principle, which is the combined form of time-temperature superposition principle and time-stress superposition principle. A unified master creep compli- ance curve was constructed from the short-term tests by joint application of time-temperature superposition and time-stress superposition. The unified master curve establishes the creep com- pliance over two years, which is 4.2 decades longer than the test duration. Moreover, it is verified that in nonlinear viscoelastic cases, the time-temperature shift factors are dependent on stresses at which the shifts are applied, while the time-stress shift factors are dependent on temperatures.

关键词： time-dependent polymer viscoelastic creep time-temperature-stress superposi-tion master curve pair-shift

TIME-TEMPERATURE-STRESS EQUIVALENCE AND ITS APPLICATION TO NONLINEAR VISCOELASTIC MATERIALS

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Acta Mechanica Solida Sinica 2001年第3期14卷 195-199页

作者： luo wenbo Yang Ting-Qing An Qunli Department of Mechanics Huazhong University of Science and TechnologyWuhan 430074China Institute of Fundamental Mechanics and Material Engineering Xiangtan UniversityXiangton 411105China

Stress-dependence of the intrinsic time of viscoelastic materialsis investigated. The influence of stress level on the intrinsic timeis considered to be similar to that of temperature, pressure, solventcon- centration, damage and physical aging. Thetime-temperature-stress equivalence principle is proposed, byemploying which, the creep curves at different temperatures andstress level can be shifted into a master curve at referencetemperature and stress level.

关键词： creep viscoelasticity time-temperature-stress equivalence principle

Growth and Carbon Metabolism Responses to Flooding Timing and Frequency in Three Marsh Plants in Sanjiang Plain

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湿地科学 2014年第1期12卷 15-21页

作者： LIU Zinan WANG Xue luo wenbo SHENG Lianxi Key Laboratory for Wetland Ecology and Vegetation Restoration of National Environmental Protection Northeast Normal University Changchun 130024 Jilin P.R.China Division of Biological Sciences University of Montana Missoula 59812 USA

Flooding timing and frequency may have different effects on the growth and carbon metabolism of plants in wetlands. We tested this hypothesis using three marsh plants in Sanjiang Plain, which were growing in different flooding timing and frequency environments for 24 days. The three marsh plants in different elevations along a water-level gradient, high-elevation species Calamagrostis angustifolia, mid-elevation species Carex limosa and low-elevation species Carex lasiocarpa. Our experiment included 6 kinds of treatments: control, longer flooding timing, medial flooding timing and frequency(2 treatments), and higher flooding frequency(2 treatments). Longer flooding timing and higher flooding frequency treatments led to similar reductions in biomass accumulation and relative growth rate of Calamagrostis angustifolia, whereas growth of Carex limosa was not affected by either flooding timing or frequency. However, biomass accumulation and relative growth rate of Carex lasiocarpa was only reduced by the higher flooding frequency. Starch and soluble sugar contents of Calamagrostis angustifolia were negatively affected by flooding frequency. On Carex limosa, higher flooding frequency resulted in higher starch content, but longer flooding timing led to accumulated starch content in Carex lasiocarpa. Soluble sugar contents of Carex lasiocarpa and Carex li mosa were not affected by either flooding timing or flooding frequency. These results indicated that growth responses of the three marsh plants to flooding timing and frequency was closely related to the different physiology of carbohydrate metabolism.

关键词：植物学研究演化植物生理学

Decoding fear of negative evaluation from brain morphology:A machine-learning study on structural neuroimaging data

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Quantitative Biology 2022年第4期10卷 390-402页

作者： Chunliang Feng Frank Krueger Ruolei Gu wenbo luo Key Laboratory of Brain Cognition and Education Sciences(South China Normal UniversityMinistry of Education)Guangzhou 510631China Guangdong Provincial Key Laboratory of Mental Health and Cognitive Science Center for Studies of Psychological ApplicationSchool of PsychologySouth China Normal UniversityGuangzhou 510631China School of Systems Biology George Mason UniversityFairfaxVA 22030USA Department of Psychology George Mason University of MannheimMannheim 68159Germany Key Laboratory of Behavioral Science Institute of PsychologyChinese Academy of SciencesBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 100101China Research Center of Brain and Cognitive Neuroscience Liaoning Normal UniversityDalian 116029China

Background:Fear of negative evaluation(FNE),referring to negative expectation and feelings toward other people’s social evaluation,is closely associated with social anxiety that plays an important role in our social *** the neural markers of FNE may be of theoretical and practical significance to psychiatry research(e.g.,studies on social anxiety).Methods:To search for potentially relevant biomarkers of FNE in human brain,the current study applied multivariate relevance vector regression,a machine-learning and data-driven approach,on brain morphological features(e.g.,cortical thickness)derived from structural imaging data;further,we used these features as indexes to predict self-reported FNE score in each ***:Our results confirm the predictive power of multiple brain regions,including those engaged in negative emotional experience(e.g.,amygdala,insula),regulation and inhibition of emotional feeling(e.g.,frontal gyrus,anterior cingulate gyrus),and encoding and retrieval of emotional memory(e.g.,posterior cingulate cortex,parahippocampal gyrus).Conclusions:The current findings suggest that anxiety represents a complicated construct that engages multiple brain systems,from primitive subcortical mechanisms to sophisticated cortical processes.

关键词： fear of negative evaluation social anxiety structural magnetic resonance imaging machine learning relevance vector regression

Single-trial ERP evidence for the three-stage scheme of facial expression processing

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Science China(Life Sciences) 2013年第8期56卷 835-847页

作者： ZHANG DanDan luo wenbo luo YueJia Institute of Affective and Social Neuroscience Shenzhen University State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University School of Psychology Liaoning Normal University Laboratory of Cognition and Mental Health Chongqing University of Arts and Sciences Sichuan Research Center of Applied Psychology Chengdu Medical College

Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the current study, we investigated the six discriminating components on a single-trial level to clarify whether the amplitude difference between experimental conditions results from a difference in the real variability of single-trial amplitudes or from latency jitter across trials. It is found that there were consistent amplitude differences in the single-trial P1, N170, VPP, N3, and P3 components, demonstrating that a substantial proportion of the average amplitude differences can be explained by the pure variability in amplitudes on a single-trial basis between experimental conditions. These single-trial results verified the three-stage scheme of facial expression processing beyond multitrial ERP averaging, and showed the three processing stages of "fear popup", "emotional/unemotional discrimination", and "complete separation" based on the single-trial ERP dynamics.

关键词： facial expression single trial event-related potential (ERP) three stages

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Thermal stability analysis of a satellite-borne optical bench based on quasi-kinematic support

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Earth and Planetary Physics 2023年第1期7卷 119-124页

作者： Huan Zhang ChunYu Yu Le Suo wenbo luo Ding Yuan JiaMing Ou Beijing Institute of Spacecraft System Engineering Beijing 100094China Institute of Remote Sensing Satellite China Academy of Space TechnologyBeijing 100094China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacaoChina

Macao Science Satellite-1(known as MSS-1)is a low-inclination mission that will be launched at the beginning of *** optical bench is used for accessing high-precision strength and direction measurements of the magnetic *** this paper,we present a thermal stability design for the optical bench based on quasi-kinematic support by kinematic hinges on the *** change in angles with the finite element method(FEM)model modified by thermal deformation test data is *** robustness of the structure is also investigated via the Monte Carlo *** main results are ***,the peak-to-peak value(Vp-p)of the inter-boresight angle is at most 1.24″,and the Vp-p of the inter-boresight angle modification and analysis is no more than 3.13″,both of which are better than those on the Swarm satellites in ***,the 90°fibers of the carbon-reinforced arm need to be strictly controlled during the technological process.

关键词： thermal stability finite element method Monte Carlo

High-tenacity in-situ Ti/Zr-based bulk metallic glasses composites fabricated by industrial high-pressure die casting

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Journal of Materials Science & Technology 2024年第3期170卷 177-185页

作者： Yang Li wenbo luo Ying Jin Zhiyong Xue Guiqing Wang Yanan Ren Haoxin Li Haibo Ke Baoan Sun Weihua Wang Institute for Advanced Materials North China Electric Power UniversityBeijing 102206China Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China

The glass-forming ability and mechanical properties of metallic glasses and their composites are well known to be sensitive to the preparation conditions and are highly deteriorated by industrial preparing conditions such as low-purity raw materials and low ***,we showed that a series of in-situ bulk metallic glass composites(BMGCs)which exhibit excellent ductility and segmental work hardening were successfully developed utilizing a high vacuum high-pressure die casting(HV-HPDC)technology along with industrial-grade raw *** tensile properties of these BMGCs are systematically investigated and correlated with the alloy *** compared with the copper mold suction casting method,the volume fraction difference of the dendrite phase for the BMGCs with the same composition is not significant when fabricated by the HV-HPDC,whereas the size of theβ-phase is generally *** BMGCs with the composition of Ti_(48)Zr_(20)(V_(12/17)Cu_(5/17))19 Be 13 obtained by the HV-HPDC process show ductility up to 11.3%under tension at room temperature and exhibit a certain amount of work *** conditions need to be met to enable the BMGCs,which are prepared by vacuum die-casting to retain favorable ductility:(1)The volume fraction ofβphase stays below 62%±2%;(2)The equiaxed crystals with a more uniform size in the range of 5-10μ***,the results of the present study provided guidance for developing BMGCs with good ductile properties under industrial conditions.

关键词： Vacuum die casting Bulk metallic glass composites Mechanical properties β-phase

Design,preparation,microstructure and mechanical property of the lightweight radiation-shielding Mg-Ta-Al composites basing differential temperature hot rolling

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Journal of Magnesium and Alloys 2024年第6期12卷 2433-2446页

作者： wenbo luo Songya Feng Xiuzhu Han Li Zhou Qinke Kong Zhiyong Xue Jianzhao Wang Mei Zhan Xianhua Chen Fusheng Pan Institute for Advanced Materials North China Electric Power UniversityBeijing 102206China Beijing Institute of Spacecraft System Engineering Beijing 100094China Sinosteel Equipment&Engineering Co Ltd.Beijing100080China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Inner Mongolia 014030China School of Materials Science Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China

A novel lightweight,radiation-shielding Mg-Ta-Al layered metal-matrix composite(LMC)was successful designed by doping the extremely refractory metal(Ta)into Mg *** Mg-based LMCs sheets shows excellent radiation-dose shield effect,about 145 krad·a^(−1),which is about 17 times of traditional Mg alloy,while its surface density is only about 0.9 g·cm^(−2),reducing by 60%than that of pure *** quantitate relationship between radiation-dose and the materials’thickness was also confirmed to the logistic function when the surface density is in the range of 0.6-1.5 g·cm^(−2).Meantime,the rolling parameters,interface microstructure and mechanical properties in both as-rolled and annealing treated samples were *** sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface,as well as a thin Al film with a thickness of about 10μ*** special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al *** interface bonding strength reaches up to 54-76 *** ultimate tensile strength(UTS)and yield strength(TYS)of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa,respectively,along with an elongation of 5.8%.The molecular dynamics(MD)analysis results show that the two interfaces exhibit different formation mechanism,the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement,while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

关键词： Dissimilar metals composites Mg based alloys Radiation shielding Hot rolling Lightweight

Enhancing pain modulation: the efficacy of synchronous combination of virtual reality and transcutaneous electrical nerve stimulation

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General Psychiatry 2023年第6期36卷 501-511页

作者： Yanzhi Bi Xu Liu Xiangyue Zhao Shiyu Wei Jingwei Li Faguang Wang wenbo luo Li Hu CAS Key Laboratory of Mental Health Institute of PsychologyChinese Academy of SciencesBeijingChina Department of Psychology University of Chinese Academy of SciencesBeijingChina Research Center of Brain and Cognitive Neuroscience Liaoning Normal UniversityDalianLiaoningChina School of Inteligent Manufacturing Wenzhou PolytechnicWenzhouZhejangChina Key Laboratory of Brain and Cognitive Neuroscience DalianLiaoningChina

Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain ***,their standalone applications often yield limited analgesic effects,particularly in certain painful *** Our hypothesis was that the combination of VR with TENS in a synchronous manner could produce the best analgesic effect among the four experimental *** To address this challenge,we proposed a novel pain modulation strategy that synchronously combines VR and TENS,aiming to capitalise on both techniques'complementary pain modulation ***-two healthy subjects participated in the study and underwent three types of interventions:VR alone,a combination of VR with conventional TENS,and a combination of VR with synchronous ***,a control condition with no intervention was *** pain intensity,pain unpleasantness,positive and negativeaffect scores,and electroencephalographic(EEG)data were collected before and after the *** delve into the potential moderating role of pain intensity on the analgesic efficacy of VR combined with synchronous TENS,we incorporated two distinct levels of painful stimuli:one representing mild to moderate pain(ie,low pain)and the other representing moderate to severe pain(ie,high pain).Results Our findings revealed that both combination interventions exhibited superior analgesic effects compared with the VR-alone intervention when exposed to low and high pain ***,the combination of VR with synchronous TENS demonstrated greater analgesic efficacy than the combination of VR with conventional *** data further supported these results,indicating that both combination interventions elicited a greater reduction in event-related potential magnitude compared with the VR-alone intervention during exposure to low and high pain ***,the synchronous combination intervention induced a more significant reduc

关键词： pain stimulation alone