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Elastic Modulus Effect Related with Nonlinear Internal Friction

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Chinese Physics Letters 1992年第1期9卷 26-29页

作者： tan qi Laboratory of Internal Friction and Defects in Solids University of Science and Technology of ChinaHefei 230026

The behavior of elastic modulus related with strain amplitude is *** was found that modulus behaves softening when internal friction exhibits normal amplitude-dependent effects,while increases slightly with the appearance of anomalously amplitude-dependent *** the decrease of frequency of measurement,the variation of modulus with amplitude becomes small.A trial for obtaining information from amplitude internal friction peak was made on the basis of Debye equations.

关键词： friction softening modulus

Bainite isothermal transformation of Si–Mn–Mo alloy by phase structure factor calculation under different rare earth contents

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Rare Metals 2014年第4期33卷 427-432页

作者： Yan-Liang Yi Yi-Long Liang qi-Bing tan The Key Laboratory for Mechanical Behavior and Microstructure of Materials School of Materials and MetallurgyGuizhou University

The effect of rare earth （RE） on bainite trans- formation mechanism is not yet unified in the academia. Therefore, further studying the effect of RE on bainite transformation mechanism will have important guiding significance for the development of bainite steels. In this paper, using differential dilatometer （DIL805A/D）, heat treatment was performed and C-curve was drawn. The effect of phase structure factor on bainite transformation under two different fractions of RE in Si-Mn-Mo bainite steels was investigated by the empirical electron theory （EET） of solids, molecules, dilatometry, and metallogra- phy. Experimental results show that RE makes Fe-C- RE segregation structural unit of Si-Mn-Mo bainite steels increase, i.e., the values of phase structure factor （na, FDC） increase, and delay bainite transformation due to the drag effect resulting from the segregation of RE ferrite island interphase and the retardation of RE to carbon diffusion in Si-Mn-Mo bainite steels. Beside this, C-curve is shifted to right and down, and microstructures of bainite ferrite and substructures are finer.

关键词： Phase structure factor C-curve Substructure Rare earths

EFFECT OF BIAS STRESS ON NON-LINEAR INTERNAL FRICTION OF Al-Mg ALLOY

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Acta Metallurgica Sinica(English Letters) 1992年第3期5卷 166-171页

作者： tan qi University of Science and Technology of China,Hefei,China Univ of Science and Technology of China Hefei China

The influence of longitudinal and torsional bias stresses on anomalous amplitude-dependent internal friction was *** longitudinal bias stress may always weaken the anomalous amplitude-dependent effect,while the torsional one may induce different effects from differ- ent directions *** stress effect exhibits only in properly heat treated and cold worked ahoy *** anomalous amplitude-dependent internal friction peaks,P_3,P_2 and P_1, are found to be related closely to slant dislocation kink ***,the application of bias stress to internal friction would be contributed to the study on dislocation structure.

关键词： internal friction bias stress anomalous amplitude effect dislocation kink

A fast classification scheme and its application to face recognition

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第7期14卷 561-572页

作者： Xiao-hu MA Yan-qi tan Gang-min ZHENG School of Computer Science and Technology Soochow University

To overcome the high computational complexity in real-time classifier design, we propose a fast classification scheme. A new measure called 'reconstruction proportion' is exploited to reflect the discriminant information. A novel space called the 'reconstruction space' is constructed according to the reconstruction proportions. A point in the reconstruction space denotes the case of a sample reconstructed using training samples. This is used to search for an optimal mapping from the conventional sample space to the reconstruction space. When the projection from the sample space to the reconstruction space is obtained, a new sample after mapping to the new discriminant space would be classified quickly according to the reconstruction proportions in the reconstruction space. This projection technique results in a diversion of time-consuming calculations from the classification stage to the training stage. Though training time is prolonged, it is advantageous in that classification problems such as identification can be solved in real time. Experimental results on the ORL, Yale, YaleB, and CMU PIE face databases showed that the proposed fast classification scheme greatly outperforms conventional classifiers in classification accuracy and efficiency.

关键词： Reconstruction proportion Reconstruction space Real-time classification Face recognition

A Systematic Review of the Definition,Measurement,and Associated Factors of Pandemic Fatigue

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China CDC weekly 2024年第36期6卷 924-933,I0007页

作者： Ruohan Chen qi tan Bowen Su Shuqi Wang Zhanwei Du WHO Collaborating Center for Infectious Disease Epidemiology and Control School of Public HealthLKS Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Laboratory of Data Discovery for Health Limited Hong Kong Science ParkHong Kong Special Administrative RegionChina Nanjing Tech University Nanjing CityJiangsu ProvinceChina School of Cybersecurity Northwestern Polytechnical UniversityXi’an CityShaanxi ProvinceChina.

The rapid emergence and widespread transmission of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)have prompted governments worldwide to enact policies and measures to manage the virus’s *** interventions have substantially contributed to controlling disease ***,they have also significantly disrupted daily life,leading to increased public fatigue and resistance to sustained control measures,a phenomenon known as pandemic *** develop a comprehensive understanding of pandemic fatigue,this review systematically explores the concept and identifies quantitative indicators for measuring *** reviewed studies on pandemic fatigue across various countries,summarized the contributing factors,and analyzed its impact on personal protective *** findings indicate that the enforcement of health measures significantly influences the onset of pandemic fatigue,while individual perceptions of risk can negatively affect personal protective behaviors,creating a feedback loop with increasing *** results underscore the importance of considering the current severity of the pandemic and individual decisionmaking processes in the implementation of *** our understanding of pandemic fatigue is essential for developing effective policy responses in preparation for future potential epidemics.

关键词： fatigue protective prompt

The Spread Spectrum GFDM Schemes for Integrated Satellite-Terrestrial Communication System

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China Communications 2019年第12期16卷 165-175页

作者： Yang Yang Lidong Zhu Xing Mao qi tan Zongmiao He National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

Recently, integrated Satellite-Terrestrial(S-T) communication system, especially the integration of satellite communication with 5G/6G, is regarded as a research hotpot. Future integrated S-T communication systems are demanding a more compatible and robust physical layer waveform. Considering physical layer access waveform design, this paper proposed a novel Spread Spectrum Generalized Frequency Division Multiplexing(SS-GFDM) scheme for integrated S-T communication system. Traditional GFDM has many advantages such as excellent adaptability and low out-ofband(OOB) radiation. However, because of intrinsic inter carrier interference(ICI) and low signal-to-noise ratio(SNR), the multiple access performance is degraded. In this paper, we introduced CDMA technology into GFDM. Two different spread spectrum modes, Cyclic Code Shift Keying(CCSK) soft spread spectrum and Direct Sequence Spread Spectrum(DSSS), are considered and compared in this paper to illustrate the benefits of GFDM-CDMA in low SNR scenario. Moreover, this scheme integrates the slot-ALOHA protocol with GFDM-CDMA, which extends access freedom in frequency, time and code domain. The simulation and analysis results show that the proposed GFDM-CDMA scheme reduces the performance degradation caused by interference. It is effective in typical satellite channel with low complexity. Meanwhile, the peak-average-power-ratio(PAPR) and access performance has been enhanced significantly.

关键词： integrated satellite-terrestrial communication physical layer access waveform GFDM-CDMA S-ALOHA

Centrifuge study on behavior of raft foundation after tunnelling in soft clay

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Underground Space 2024年第4期17卷 161-169页

作者： Jian Yu Jiaming Liu Chun Fai Leung Maosong Huang qi Wen Jorgin tan Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationTongji UniversityShanghai 200092China Centre for Offshore Research and Engineering Department of Civil and Environmental EngineeringNational University of Singapore119077Singapore Land Transport Authority 219428Singapore

Ground losses due to tunneling would induce settlement of nearby raft *** study the change in behavior of the raft foundations over time due to tunnel excavation in soft clay,a series of centrifuge model tests were *** results reveal that the raft stiffness has a significant influence on the development of the gap between the raft and the *** width of the gap beneath the flexible foundation would increase over time,leading to a further increase in tensile strain after excavation,whereas the gap for raft foundations with a large stiffness would reduce with time,causing a gradual decrease in tensile *** modification factor(MF)design approach is also evaluated with the test results and demonstrates that the MF design approach would underestimate the tensile strain of the flexible raft and provide a relatively conservative prediction for larger stiffnesses.

关键词： Tunnelling Raft Clay Deflection ratio Centrifuge test

Stochastic scheduling with compatible job families by an improved Q-learning algorithm 36

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Stochastic scheduling with compatible job families by an imp...

Factors influencing oil recovery by surfactant-polymer flooding in conglomerate reservoirs and its quantitative calculation method

第36届中国控制会议

作者： Yilin Xiao qi tan Lei Zhou Hao tang School of Electrical Engineering and Automation Hefei University of Technology

ISBN: (纸本)9781538629185

We consider a system that a single batch processing machine can serve compatible job families(jobs from different families can be processed together in the same batch). The system is characterized by random jobs arrival, random processing time and unlimited buffer capacities. Optimization scheduling method needs to be used with the objective to minimize average cycle time in the long run. First, the stochastic scheduling problem is modeled as a continuous time Markov decision process(CTMDP) with average-cost criteria. Then, a Q-learning algorithm combined with simulated annealing technique(SA-Q learning) is used to derive the optimal or near-optimal policy to schedule the batch processing machine. Computational simulations on randomly generated instances show the effectiveness of the method.

关键词： Batch scheduling compatible job families CTMDP SA-Q learning

来源： cnki会议评论

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Petroleum Science 2022年第3期19卷 1198-1210页

作者： Feng-qi tan Chun-Miao Ma Jian-Hua qin Xian-Kun Li Wen-Tao Liu College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China Key Laboratory Computational Geodynamics Chinese Academy of SciencesBeijing100049China Xinjiang Oilfield Company PetroChinaKaramayXinjiang834000China

This study aims to clarify the factors influencing oil recovery of surfactant-polymer(SP)flooding and to establish a quantitative calculation model of oil recovery during different displacement stages from water flooding to SP *** conglomerate reservoir of the Badaowan Formation in the seventh block of the Karamay Oilfield is selected as the research object to reveal the start-up mechanism of residual oil and determine the controlling factors of oil recovery through SP flooding experiments of natural cores and microetching *** experimental results are used to identify four types of residual oil after water flooding in this conglomerate reservoir with a complex pore structure:oil droplets retained in pore throats by capillary forces,oil cluster trapped at the junction of pores and throats,oil film on the rock surface,isolated oil in dead-ends of flow *** the four types of residual oil identified,the SP solution can enhance oil recovery by enlarging the sweep volume and improving the oil displacement ***,the viscosity-increasing effect of the polymer can effectively reduce the permeability of the displacement liquid phase,change the oil-water mobility ratio,and increase the water ***,the stronger the shear drag force of the SP solution,the more the crude oil in a porous medium is ***,the surfactant can change the rock wettability and reduce the absorption capacity of residual oil by lowering interfacial *** the same time,the emulsification further increases the viscosity of the SP solution,and the residual oil is recovered effectively under the combined effect of the above two *** the four start-up mechanisms of residual oil identified after water flooding,enlarging the sweep volume and improving the oil displacement efficiency are interdependent,but their contribution to enhanced oil recovery are *** SP flooding system primarily enlarges the sweep volume by increasing viscos

关键词： Conglomerate reservoir Water flooding Surfactant-polymer flooding Residual oil type Influencing factor Enhanced oil recovery Computational model