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AWells-Riley/based COVID-19 infectiousrisk assessment model combining both short rangeandroom scale effects

Building Simulation 2024年第1期17卷 93-111页

作者： Yinshuai feng Yifan Fan Xiaoyu Luo Jian Ge College of Civil Engineering and Architecture Zhejiang UniversityHangzhouChina Center for Balance Architecture Zhejiang UniversityHangzhouChina International Research Center for Green Building and Low-Carbon City International CampusZhejiang UniversityHainingChina

There is growing evidence of the high transmission potential of COVID-19 through virus-laden *** aerosols are inhaled in various concentrations,an overall assessment of transmission risks at different indoor scales is ***,a comprehensive risk assessment method that evaluates the direct link between short-range and room-scale zones is stl *** this paper,a risk assessment model combining both short-range and room-scale effects is developed to obtain effective reproduction number in confined indoor environments,called Turbulent Jet Wells Riley(TJWR)*** with the viral load data and aerosol generation data of different human respiratory activities,the monte Carlo simulation method is applied to calculate the quanta emission rate,which further provides the input parameters of the TJWR *** known outbreaks(Hangzhou banquet hall X,Guangzhou restaurant Y,and Hong Kong restaurant Z,China)are chosen to validate the TJWR *** show that the TJWR model is more efficient than the original Wells-Riley *** average relative error of the TJWR model ranges between 9%and 44%,while for the Wells-Riley model,it ranges between 57%and 78%.The TJWR model also proves that infection risk assessments using the well-mixed assumption can systematically underestimate the transmission risk for those close to the ***,there is a significant positive linear correlation between the total number of exposed individuals at the short-range and the effective reproduction *** newly developed TJWR model has great potential for rapid and real-time overall airborne transmission risk assessment in buildings and cities.

关键词： COVID-19 airborne transmission infection risk Wells-Riley model monte Carlo simulation

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Regulatory mechanisms for Transcriptional Bursting Revealed by an Event-Based model

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Research 2024年第3期2023卷 217-231页

作者： Renje Wu Bangyan Zhou Wei Wang feng Liu National Laboratory of Solid State microstructures Department of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093P.R.China Institute for Brain Sciences Nanjing UniversityNanjing 210093P.R.China.

Gene transcription often occurs in discrete bursts, and it can be difficult to deduce the underlying regulatory mechanisms for transcriptional bursting with limited experimental data. Here, we categorize numerous states of single eukaryotic genes and identify 6 essential transcriptional events, each comprising a series of state transitions;transcriptional bursting is characterized as a sequence of 4 events, capable of being organized in various configurations, in addition to the beginning and ending events. By associating transcriptional kinetics with mean durations and recurrence probabilities of the events, we unravel how transcriptional bursting is modulated by various regulators including transcription factors. Through analytical derivation and numerical simulation, this study reveals key state transitions contributing to transcriptional sensitivity and specificity, typical characteristics of burst profiles, global constraints on intrinsic transcriptional noise, major regulatory modes in individual genes and across the genome, and requirements for fast gene induction upon stimulation. It is illustrated how biochemical reactions on different time scales are modulated to separately shape the durations and ordering of the events. Our results suggest that transcriptional patterns are essentially controlled by a shared set of transcriptional events occurring under specific promoter architectures and regulatory modes, the number of which is actually limited.

关键词： kinetics essentially constraints

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Effect of oxide inclusions on mnS precipitates and tensile mechanical property of high-strength low-alloy steel

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Journal of Iron and Steel Research International 2024年第5期31卷 1210-1220页

作者： Xiao-yong Gao Hong Wei Li-feng Zhang School of mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of materials Science and Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of mechanical and materials Engineering North China University of TechnologyBeijing100144China

The key role of oxide inclusions on the microstructure and mechanical property of a high-strength low-alloy steel was *** field emission scanning electron microscope equipped with energy-dispersive spectrometry was used to characterize mnS *** inclusions play an important role in the shape control of mnS *** oxides fovored to decrease the size and the aspect ratio of mnS *** less oxide inclusions in the steel,approximately over 16.7%mnS precipitates were with aspect ratio a>5 and pure mnS precipitates accounted for 75.9%in ***,with more oxide inclusions in the steel,only 7.4%mnS precipitates were with a>5 and pure mnS precipitates accounted for 60.1%in *** of mnS by oxide inclusions improved the strength and inhibited the *** oxide inclusions in the steel increased the yield strength and tensile strength of the steel in both longitudinal and transverse directions,and lowered the anisotropy of the mechanical property.

关键词： High-strength low-alloy steel mnS Oxide inclusion mechanical property Anisotropy

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multi-Objective Optimization of VBHF in Deep Drawing Based on the Improved QO-Jaya Algorithm

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Chinese Journal of mechanical Engineering 2024年第1期37卷 189-202页

作者： Xiangyu Jiang Zhaoxi Hong Yixiong feng Jianrong Tan State Key Laboratory of Fluid Power and mechatronic Systems Zhejiang UniversityHangzhou 310027China Key Laboratory of Advanced manufacturing Technology of Zhejiang Province Zhejiang UniversityHangzhou 310027China Ningbo Innovation Center Zhejiang UniversityNingbo 315100China

Blank holder force(BHF)is a crucial parameter in deep drawing,having close relation with the forming quality of sheet ***,there are different BHFs maintaining the best forming effect in different stages of deep *** variable blank holder force(VBHF)varying with the drawing stage can overcome this problem at an *** optimization of VBHF is to determine the optimal BHF in every deep drawing *** this paper,a new heuristic optimization algorithm named Jaya is introduced to solve the optimization *** improved“Quasi-oppositional”strategy is added to Jaya algorithm for improving population ***,an innovated stop criterion is added for better ***,the quality evaluation criteria for wrinkling and tearing are ***,the Kriging models are developed to approximate and quantify the relation between VBHF and forming defects under random ***,the optimization models are established and solved by the improved QO-Jaya algorithm.A VBHF optimization example of component with complicated shape and thin wall is studied to prove the effectiveness of the improved Jaya *** optimization results are compared with that obtained by other algorithms based on the TOPSIS method.

关键词： Variable blank holder force multi-objective optimization QO-Jaya algorithm Algorithm stop criterion

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mechanistic insights into stepwise activation of malachite for enhancing surface reactivity and flotation performance

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International Journal of minerals,metallurgy and materials 2024年第10期31卷 2159-2172页

作者： Qicheng feng Wanming Lu Han Wang Qian Zhang State Key Laboratory of Complex Nonferrous metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green Separation and Enrichment of Strategic mineral Resources Kunming University of Science and TechnologyKunming 650093China

malachite is a common copper oxide mineral that is often enriched using the sulfidization-xanthate flotation ***,the direct sulfidization method cannot yield copper concentrate ***,a new sulfidization flotation process was developed to promote the efficient recovery of *** this study,Cu^(2+) was used as an activator to interact with the sample surface and increase its reaction sites,thereby strengthening the mineral sulfidization process and *** to single copper ion activation,the flota-tion effect of malachite significantly increased after stepwise Cu^(2+) *** potential,X-ray photoelectron spectroscopy(XPS),time-of-flight secondary ion mass spectroscopy(ToF-SImS),scanning electron microscopy and energy dispersive spectrometry(SEm-EDS),and atomic force microscopy(AFm)analysis results indicated that the adsorption of S species was significantly enhanced on the mineral surface due to the increase in active Cu sites after Cu^(2+) stepwise ***,the proportion of active Cu-S spe-cies also increased,further improving the reaction between the sample surface and subsequent ***-transform infrared spec-troscopy(FT-IR)and contact angle tests implied that the xanthate species were easily and stably adsorbed onto the mineral surface after Cu^(2+) stepwise activation,thereby improving the hydrophobicity of the mineral ***,the copper sites on the malachite sur-face after Cu^(2+) stepwise activation promote the reactivity of the mineral surface and enhance sulfidization flotation of malachite.

关键词： malachite copper ions stepwise activation flotation mechanism enhanced sulfidization

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Porous silica nano-flowers stabilized Pt-Pd bimetallic nanoparticles as heterogeneous catalyst for efficiently synthesizing guaiacol from 2-methoxycyclohexanol

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Chinese Journal of Chemical Engineering 2024年第6期70卷 222-233页

作者： Junbo feng Junyan Wu Dongdong Yan Yadong Zhang School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization Pingdingshan 467000China Jiyuan Research Institute Zhengzhou UniversityJiyuan 459000China School of materials and Chemical Engineering Zhongyuan University of TechnologyZhengzhou 450007China

Porous silica nano-flowers(KCC-1)immobilized Pt-Pd alloy NPs(Pt-Pd/KCC-1)with different mass ratios of Pd and Pt were successfully prepared by a facile in situ one-step reduction,using hydrazinium hydroxide as a reducing *** as-synthesized silica nanospheres possess radial fibers with a distance of 15 nm,exhibiting a high specific surface area(443.56 m^(2)·g^(-1)).meanwhile,the obtained Pt-Pd alloy NPs are uniformly dispersed on the silica surface with a metallic particle size of 4-6 nm,which exist as metallic Pd and Pt on the surface of monodisperse KCC-1,showing the transfer of electrons from Pd to *** as-synthesized 2.5%Pt-2.5%Pd/KCC-1 exhibited excellent catalytic activity and stability for the continuous dehydrogenation of 2-methoxycyclohexanol to prepare *** with Pt or Pd single metal supported catalysts,the obtained 2.5%Pt-2.5%Pd/KCC-1 shows 97.2%conversion rate of 2-methoxycyclohexanol and 76.8%selectivity for guaiacol,which attributed to the significant synergistic effect of bimetallic Pt-Pd alloy ***,turn over frequency value of the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs achieved 4.36 s^(-1),showing higher catalytic efficiency than other two monometallic *** pathways of dehydro-aromatization of 2-methoxycyclohexanol over the obtained catalyst are ***,the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs prove their potential in the dehydrogenation of 2-methoxycyclohexanol,while the kinetics and mechanistic study of the dehydrogenation reaction over the catalyst in a continuous fixed-bed reactor may provide valuable information for the development of green,outstanding and powerful synthetic pathway of guaiacol.

关键词： Supported catalyst Nanoparticles Dehydrogenation 2-methoxycyclohexanol Guaiacol

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Short-time maritime target detection based on polarization scattering characteristics

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Journal of Systems Engineering and Electronics 2024年第1期35卷 55-64页

作者： CHEN Shichao LUO feng TIAN min LYU Wanghan College of Computer and Information Engineering(College of Artificial Intelligence) Nanjing Tech UniversityNanjing 211816China Hangzhou Institute of Technology Xidian UniversityHangzhou 311200China

In this paper,a detection method combining Cameron decomposition based on polarization scattering characteristics in sea clutter background is ***,the Cameron decomposition is exploited to fuse the radar echoes of full polarization channels at the data *** to the artificial material structure on the surface of the target,it can be shown that the non-reciprocity of the target cell is stronger than that of the clutter ***,based on the analysis of the decomposition results,a new feature with scattering geometry characteristics in polarization domain,denoted as Cameron polarization decomposition scattering weight(CPD-SW),is extracted as the test statistic,which can achieve more detailed descriptions of the clutter scattering characteristics utilizing the difference between their scattering ***,the superiority of the proposed CPD-SW detector over traditional detectors in improving detection performance is verified by the IPIX measured dataset,which has strong stability under short-time observation in threshold detection and can also improve the separability of feature space zin anomaly detection.

关键词： sea clutter small target radar detection Cameron decomposition characteristics analysis

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Coarse-fine joint target parameter estimation method based on AN-RSC in OFDm passive radar

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Journal of Systems Engineering and Electronics 2024年第2期35卷 339-349页

作者： WANG Chujun WAN Xianrong YI Jianxin CHENG feng School of Electronic Information Wuhan UniversityWuhan 430072China

In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDm)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational ***,the modulation symbol domain(mSD)method is used to roughly estimate the delay and Doppler of ***,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(mmV)model(mmV-AN)is used to manifest the signal sparsity in the continuous Doppler *** the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay *** results based on the OFDm signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other *** addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.

关键词： passive radar orthogonal frequency division multiplexing(OFDm)signal atomic norm(AN) parameter estimation

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An optimized time-adaptive aerothermal coupling calculation method for aerothermal analysis of disc cavity system

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Chinese Journal of Aeronautics 2024年第9期37卷 164-177页

作者： Shuai BI Junkui mAO Lei WANG feng HAN College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 20016China AECC Aeroengine Control System Institute Wuxi 214063China Integrated Energy Institute Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In order to further achieve the balance between the calculation accuracy and efficiency of the transient analysis of the aero-engine disc cavity system,an Optimized Time-adaptive Aerother-mal Coupling calculation(OTAC)method has been *** combines one-dimensional tran-sient calculation of air system,Conventional Sequence Staggered(CSS)method,Time-adaptive Aerothermal Coupling calculation(TAC)method and differential evolution optimization algorithm to obtain an efficient and high-precision aerothermal coupling calculation method of air *** both the heat conduction in the solid domain and the flow in the fluid domain as unsteady states in the OTAC,the interaction of fluid-solid information within a single coupling time step size was implemented based on the CSS ***,the coupling time step size was automatically adjusted with the number of iterations by using the Proportional-Integral-Deri vative(PID)*** show that when compared with the traditional loosely coupling method with a fixed time step size,the computational accuracy and efficiency of the OTAC method are improved by 8.9%and 30%,*** with the tight coupling calculation,the OTAC method can achieve a speedup of 1 to 2 orders of magnitude,while the calculation error is maintained within 6.1%.

关键词： Air system 1D-3D coupling Conjugate heat transfer Transient calculation Adaptive time step size

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Kriging model Averaging Based on Leave-One-Out Cross-Validation method

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Journal of Systems Science & Complexity 2024年第5期37卷 2132-2156页

作者： feng Ziheng ZONG Xianpeng XIE Tianfa ZHANG Xinyu School of mathematics Statistics and MechanicsBeijing University of TechnologyBeijing 100124China Academy of mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

In recent years,Kriging model has gained wide popularity in various fields such as space geology,econometrics,and computer *** a result,research on this model has *** this paper,the authors propose a model averaging estimation based on the best linear unbiased prediction of Kriging model and the leave-one-out cross-validation method,with consideration for the model *** authors present a weight selection criterion for the model averaging estimation and provide two theoretical justifications for the proposed ***,the estimated weight based on the proposed criterion is asymptotically optimal in achieving the lowest possible prediction ***,the proposed method asymptotically assigns all weights to the correctly specified models when the candidate model set includes these *** effectiveness of the proposed method is verified through numerical analyses.

关键词： Asymptotic optimality best linear unbiased prediction cross-validation Kriging model model averaging

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