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Decision-making under uncertainty for buildings exposed to environmental hazards

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Journal of Safety Science and Resilience 2022年第1期3卷 1-14页

作者： hao qin School of Engineering The University of NewcastleNewcastleNSW 2308Australia School of Civil Engineering The University of QueenslandBrisbaneQld 4072Australia

Buildings are exposed to risks from environmental hazards such as earthquakes,windstorms and ***-stantial uncertainties from various sources are inevitably involved in the risk estimation and decision-making for activities such as design and disaster risk mitigation for *** makers seek to achieve economic efficiency while ensure building safety by managing the extreme tail risk that is typically a concern when facing low-probability,high-consequence ***,risk preferences and tolerances play an important role in the decision process,which often vary among different decision *** conventionally used minimum expected life-cycle cost criterion(MELC)fails to adequately cope with large uncertainty and risk *** this end,this paper presents the application of a set of decision models beyond the MELC to support decision-making under uncertainty for buildings exposed to environmental *** objective is to provide risk-informed de-cision support for decision-makers with a wide range of risk appetites while taking into account uncertainties involved in the life-cycle *** features,strengths and weaknesses of these decision models are discussed from a practical point of *** application and selection of the decision models are demonstrated by two practical decision problems:(i)seismic design of a high-rise commercial building,and(ii)wind hazard mitigation for a low-rise residential *** examples illustrate how the decisions for choosing seismic design levels and wind mitigation measures vary when different decision models and model settings are applied.

关键词： Decision-making Life-cycle cost Environmental hazards Uncertainty Risk preferences

Effects of pressure oscillation on aerodynamic characteristics in an aero-engine combustor

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Chinese Journal of Aeronautics 2021年第2期34卷 454-465页

作者： hao qin Guanqiong TANG Xionghui WANG Design and Research Center AECC Commercial Aircraft Engine Co.Ltd.Shanghai 200241China

The effects of pressure oscillation on aerodynamic characteristics in an aero-engine combustor are investigated. A combustor test rig is designed to simulate the pressure drop characteristics of a practical annular combustor. The pressure drop characteristics are firstly measured under atmosphere condition with non-reacting flow(or cold flow), and the air mass flow proportion of each component(dome/liner) are obtained;these properties are base lines for comparison with combustion state. The combustion tests are then carried out under conditions of inlet temperature 340–450 K, fuel air ratio 0.010–0.028. The stability map and the oscillation frequencies are obtained in the tests, the results show that pressure oscillation amplitude increases with the increase of fuel air ratio. Phase trajectory reconstruction is applied to classify the pressure oscillation motion;there are three motions captured in the tests including: ‘‘disk", ‘‘ring" and ‘‘cluster". The pressure drops across the dome under strong pressure oscillation are distinctly divergent from the cold flow, and the changes of pressure drops are mainly affected by pressure oscillation amplitude, but is less influenced by pressure oscillation motion nor oscillation frequencies. Based on the mass flow conservation, the reduction of effective flow area of combustor under strong pressure oscillation is demonstrated. Liner wall temperatures are analyzed through Multiple Linear Regression(MLR)method to estimate the reduction of the air mass flow proportion of the liner cooling under strong pressure oscillation. Finally, the air mass flow proportions of each component under strong pressure oscillation are estimated, the results show that the pressure oscillation motion also has influence on air mass flow proportion.

关键词： Aerodynamic Aero-engine Combustor Multiple Linear Regression Nonlinear Phase trajectory reconstruction Pressure oscillation

Soil nutrient patchiness affects nutrient use efficiency,though not photosynthesis and growth of parental Glechoma longituba ramets:both patch contrast and direction matter

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Journal of Plant Ecology 2010年第2期3卷 131-137页

作者： hao-qin Xiong State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Graduate University of Chinese Academy of Sciences Beijing 100049China Department of Environmental Science and Engineering Southwest Forestry UniversityKunming 650224China

Aims Most plants are clonal in *** ramets can share water,nutrients and photosynthate,especially when they experience patchy *** contrast(i.e.a difference in resources among patches)and patch direction(***–sink relations)are among the basic attributes of spatial ***,I hypothesize that young established ramets in nutrient-rich patches support old ramets in nutrient-poor patches when ramets are subjected to different patch contrasts and patch *** In a greenhouse experiment,old and young ramets of Glechoma longituba were grown in four combinations consisting of patch contrast and patch *** patch direction refers to a patch combination in which parent ramets grow in nutrient-rich patches while connected daughter ramets grow in nutrient-poor ones and plus patch direction is the opposite *** photosynthesis and fluorescence traits,harvested all ramets,took morphological measures,weighed their dry mass and determined their nutrient uptake and *** Findings For parental ramets of ***,patch contrast and patch direction and their interactions had no significant effects on net photosynthetic rate,maximal fluorescence yield,photochemical quenching(quenching refers to any process which decreases the fluorescence intensity of a given substance),non-photochemical quenching,nutrient uptake,biomass and stolon weight *** direction alone significantly affected root weight *** patch contrast enhanced N use efficiency(NUE)and P use efficiency(PUE);plus patch direction decreased NUE,but increased PUE;the patch contrast by patch direction interaction affected PUE and K use efficiency(KUE).There were significant interactions between patch direction and patch contrast on PUE and *** is concluded that soil nutrient patchiness may influence nutrient use strategies,but not nutrient uptake,photosynthesis and growth of parent ramets of *** connected to daughter ramets,an

关键词： chlorophyll fluorescence Glechoma longituba growth and allocation nutrient use strategy photosynthesis soil nutrient patchiness

Enhanced visible-light photocatalytic activity of a g-C_3N_4/m-LaVO_4 heterojunction: band offset determination

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Science Bulletin 2016年第8期61卷 645-655页

作者： Xiaoping Liu hao qin Weiliu Fan School of Chemistry and Chemical Engineering Shandong University State Key Laboratory of Crystal Materials Shandong University

Band offset is a dominant factor affecting the photocatalytic performance of heterostructure photocatalysts. Therefore, controlling the band gap structure of semiconductors is a key challenge in the development of efficient photocatalysts. We used a typical in situ-method to prepare diverse graphite-phase carbon nitride(g-C_3N_4)samples from melamine, thiourea, and a mixture thereof,and found that they exhibited band gaps between2.3–2.8 e V. From UV–Vis spectra and X-ray photoelectron spectroscopy measurements, we determined that the g-C_3N_4 samples exhibited different band gap values and valence band positions. On this basis, we constructed g-C_3N_4/m-La VO_4 heterojunctions with different band offsets. UV–Vis spectra and X-ray photoelectron spectroscopy measurements revealed that the valence band offsets(VBOs) of the different heterojunctions were similar, but their conduction band offsets(CBOs) were significantly different. Photocatalytic experiments revealed that the reaction rate was enhanced with an increase in the CBO value. Furthermore, the three-phase g-C_3N_4/g-C_3N_4/mLa VO_4 heterojunction composed of m-La VO_4 and mixed g-C_3N_4 showed the highest photocatalytic activity, which was mainly due to the construction of a multilevel structure. This work investigates the influence of the band offset on heterojunction photoelectrochemical properties and provides a new strategy to improve the photocatalytic activity by constructing multilevel structures.

关键词： Carbon nitride.Visible light photocatalysis ~PrecursorsBand offset. MultilevelHeterojunction

Facile fabrication of a nanoporous Si/Cu composite and its application as a high-performance anode in lithiumion batteries

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Nano Research 2016年第4期9卷 908-916页

作者： Caixia Xu qin hao Dianyun Zhao School of Chemistry and Chemical Engineering University of Jinan Jinan 250022 China

Nanoporous （NP） Si/Cu composites are fabricated by means of alloy refining followed by facile electroless deaUoying in mild conditions. NP-SidCu composites with a three-dimensional porous network nanoarchitecture with different Cu contents are obtained by changing the feeding ratio of alloy precursors. Owing to the rich porosity and integration of conductive Cu into a nanoporous Si backbone, the NP-Si^Cu15 composite exhibits modified conductivity and reduced volumetric expansion/fracture during repeated charging-discharging processes in lithium-ion batteries （LIBs）, thus exhibiting much higher cycling reversibility than NP-Si92Cu8 and pure NP-Si. With the advantages of unique performance and easy preparation, NP-Si/Cu composite has potential for application as an advanced anode material for LIBs.

关键词： porous silicon composite lithium-ion batteries dealloying

Precessing motion in stratified radial swirl flow

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Chinese Journal of Aeronautics 2016年第2期29卷 386-394页

作者： qin hao Lin Yuzhen Li Jibao National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power Engineering Beihang University AVIC Commercial Aircraft Engine Co. Ltd.

Vortex/flame interaction is an important mechanism for unsteady combustion in a swirl combustion system. Technology of low emission stirred swirl （TeLESS）, which is characterized with stratified swirl flow, has been developed in Beihang University to reduce NOx emission. However, large-scale flow structure would be induced in strong swirl flow. Experiments and computational fluid dynamics （CFD） simulation were carried out to investigate the unsteady flow feature and its mechanism in TeLESS combustor. Hotwire was firstly applied to testing the unsteady flow feature and a distinct mode with 2244 Hz oscillation frequency occurred at the pilot swirl outlet. The flow mode amplitude decayed convectively. Large eddy simulation （LES） was then applied to predicting this flow mode and know about its mechanism. The deviation of mode prediction compared with hotwire test was 0.8%. The spiral isobaric structure in pilot flow passage indicates that precessing vortex core （PVC） existed. The velocity spectrum and phase lag analysis suggest that the periodic movement at the pilot outlet was dominated by precessing movement. Negative tangen- tial momentum gradient reflects that the swirl flow was unstable. Another phenomenon was found out that the PVC movement was intermittently rotated alon~ the symmetric axis.

关键词： Large eddy simulationPrecessing motion Stratified flow Swirl flow Unsteady flow

Resource Allocation in Multi-User Cellular Networks:A Transformer-Based Deep Reinforcement Learning Approach

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China Communications 2024年第5期21卷 77-96页

作者： Zhao Di Zheng Zhong qin Pengfei qin hao Song Bin State Key Laboratory of Integrated Services Networks Xidian University710071China China Academy of Space Technology Beijing 100081China

To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing *** this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user *** first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)***,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource *** results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance.

关键词： dynamic resource allocation multi-user cellular network spectrum efficiency user fairness

PEMFC Identification Based on a Fractional-Order Hammerstein State-Space Model with ADE-BH Optimization

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China Petroleum Processing & Petrochemical Technology 2023年第2期25卷 155-164页

作者： qin hao Qi Zhidong Ye Weiqin Sun Chengshuo Nanjing University of Science and Technology Nanjing 210094China

Considering the fractional-order and nonlinear characteristics of proton exchange membrane fuel cells(PEMFC),a fractional-order subspace identification method based on the ADE-BH optimization algorithm is proposed to establish a fractional-order Hammerstein state-space model of ***,a Hammerstein model is constructed by connecting a linear module and a nonlinear module in series to precisely depict the nonlinear property of the *** the modeling process,fractional-order theory is combined with subspace identification,and a Poisson filter is adopted to enable multi-order derivability of the data.A variable memory method is introduced to reduce computation time without losing ***,to improve the optimization accuracy and avoid obtaining locally optimum solutions,a novel ADEBH algorithm is employed to optimize the unknown parameters in the identification *** this algorithm,the Euclidean distance serves as the theoretical basis for updating the target vector in the absorption-generation operation of the black hole(BH)***,simulations demonstrate that the proposed model has small output error and high accuracy,indicating that the model can accurately describe the electrical characteristics of the PEMFC process.

关键词： PEMFC Hammerstein model Fractional subspace identification ADE-BH optimization

The Sensitive Regions Identified by CNOPs of Three Typhoon Events

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Atmospheric and Oceanic Science Letters 2010年第3期3卷 170-175页

作者： qin Xiao-hao The State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

In this paper, several sets of observing system simulation experiments (OSSEs) were designed for three typhoon cases to determine whether or not the additional observation data in the sensitive regions identified by conditional nonlinear optimal perturbations (CNOPs) could improve the short-range forecast of typhoons. The results show that the CNOPs capture the sensitive regions for typhoon forecasts, which implies that conducting additional observation in these specific regions and eliminating initial errors could reduce forecast errors. It is inferred from the results that dropping sondes in the CNOP sensitive regions could lead to improvements in typhoon forecasts.

关键词： adaptive observations conditional nonlinear optimal perturbation sensitive regions Observing system simulation experiments typhoon forecast