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Machine learning-assisted sparse observation assimilation for real-time aerodynamic field perception

Science China(Technological Sciences) 2024年第5期67卷 1458-1469页

作者： zhao QingYu HUANG jun GUO YuXin PAN YuXuan ji jingjing HUANG YongAn State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Accurate aerodynamic distribution perception and real-time flight state evaluation are crucial for flight safety,e.g.,stall detection.However,the observations are usually sparse due to limitations in sensor mounting space and cost,and a reconstruction technology is urgently required.Herein,a machine learning-assisted assimilation method based on sparse observations has been proposed.Different from the traditional reconstruction methods focusing on boundary condition correction,the proposed method formulates the flow field pressure distribution as a linear superposition of flow field modes,thereby forming a real-time reconstruction pattern that combines offline modal extraction using computational fluid dynamics(CFD)with real-time determination of modal weights using a neural network.In this study,CFD simulations were conducted under 800different operating conditions for common modal extraction and model training.The weights of these modes were determined online based on merely five observations for reconstructing the full pressure field.A pressure reconstruction with a relative error of 6.1%and a mean square error of 0.003 was achieved within the prescribed condition range.The computational cost was just2 ms for each reconstruction run,significantly faster than the 20 min required by the classical reconstruction ensemble transform Kalman filter.It also showed that the method maintains almost the same accuracy amidst 1.5%measurement noise.As practical examples,shock waves and the change of lift coefficient were analyzed using the proposed method,providing remarkable evidence for the capability of the method in supporting stall detection.These validate the method’s effectiveness and explore its potential in real-time and accurate monitoring of an aircraft.

关键词： aerodynamic force sparse observation neural networks pressure field reconstruction

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Safflower Yellow Inhibits Progression of Hepatocellular Carcinoma by Modulating Immunological Tolerance via FAK Pathway

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Chinese Journal of Integrative Medicine 2024年第4期30卷 339-347页

作者： ji Hua-feng YANG Zi-qiang HAN jun-jun LI He-fang jiN zhao-qing CHEN Wei-qing CHEN Fei-hua GONG Mou-chun Department of General Surgery First People's Hospital of Hangzhou Lin'an DistrictHangzhou(311300)China

Objective To explore the anti-tumor effect of safflower yellow(SY)against hepatocellular carcinoma(HCC)and the underlying potential mechanism.Methods An in vitro model was established by mixing Luc-Hepa1-6 cells and CD3^(+)CD8^(+)T cells,followed by adding programmed cell death protein 1(PD-1)antibody(Anti-mPD-1)with or without SY.The apoptosis was detected by flow cytometry and the level of inflammatory cytokines was determined by enzyme-linked immunosorbent assay.The protein levels of programmed cell death 1 ligand 1(PD-L1),chemokine ligand(CCL5),C-X-C motif chemokine ligand 10(CXCL10)were measured by Western blot.An in situ animal model was established in mice followed by treatment with anti-mPD-1 with or without SY.Bioluminescence imaging was monitored with an AniView 100 imaging system.To establish the FAK-overexpressed Luc-Hepa1-6 cells,cells were transfected with adenovirus containing pcDNA3.1-FAK for 48 h.Results The fluorescence intensity,apoptotic rate,release of inflammatory cytokines,and CCL5/CXCL10 secretion were dramatically facilitated by anti-mPD-1(P<0.01),accompanied by an inactivation of PD-1/PD-L1 axis,which were extremely further enhanced by SY(P<0.05 or P<0.01).Increased fluorescence intensity,elevated percentage of CD3+CD8+T cells,facilitated release of inflammatory cytokines,inactivated PD-1/PD-L1 axis,and increased CCL5/CXCL10 secretion were observed in Anti-mPD-1 treated mice(P<0.01),which were markedly enhanced by SY(P<0.05 or P<0.01).Furthermore,the enhanced effects of SY on inhibiting tumor cell growth,facilitating apoptosis and inflammatory cytokine releasing,suppressing the PD-1/PD-L1 axis,and inducing the CCL5/CXCL10 secretion in Anti-mPD-1 treated mixture of Luc-Hepa1-6 cells and CD3+CD8+T cells were abolished by FAK overexpression(P<0.01).Conclusion SY inhibited the progression of HCC by mediating immunological tolerance through inhibiting FAK.

关键词： hepatocellular carcinoma safflower yellow Chinese medicine tumor microenvironment programmed cell death protein 1 focal adhesion kinase

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Degradation of warm permafrost and talik formation on the Qinghai-Tibet Plateau in 2006-2021

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Advances in Climate Change Research 2024年第2期15卷 275-284页

作者： Qi-Hang MEI ji CHEN You-Qian LIU Shou-Hong ZHANG jing-Yi zhao Tian-Chun DONG jun-Cheng WANG Yao-jun zhao Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment Key Laboratory of Cryospheric Science and Frozen Soil EngineeringNorthwest Institute of Eco-Environmental and ResourcesChinese Academy of SciencesLanzhou 730000China China Railway Qinghai-Tibet Group Co.Ltd Xining 810007China University of Chinese Academy of Sciences Beijing 100049China

Permafrost is degrading globally,particularly those with low thermal stability on the Qinghai-Tibet Plateau,owing to climate change.However,the inadequacy of direct research on permafrost degradation based on in-situ monitoring limits the prediction of permafrost degradation and engineering practices.This study explored the processes and modes of permafrost degradation into talik by analyzing ground temperature data from five points in the hinterland of the Qinghai-Tibet Plateau from 2006 to 2021.The results showed that the degradation of the warm permafrost layer with a geothermal gradient of zero occurred simultaneously in the top and bottom directions.The rate of permafrost degradation from the top down and bottom up increase during the degradation process,but the increase of the former is more drastic after the formation of thawed interlayer.Additionally,the construction of the Qinghai-Tibet Railway changed the degradation modes of the permafrost in adjacent natural sites through horizontal heat transfer,particularly after through talik formation under the embankment.The findings suggest that taking countermeasures before or immediately after forming thawed interlayer is more effective.When evaluating the thermal impact of projects in warm permafrost regions,special attention should be given to the horizontal heat transfer process that may result from the formation of a through talik.

关键词： Warm permafrost Degradation Talik Qinghai-Tibet Plateau Climate change

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A novel small-signal equivalent circuit model for GaN HEMTs incorporating a dual-field-plate

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Journal of Semiconductors 2024年第5期45卷 61-68页

作者： jinye Wang jun Liu Zhenxin zhao School of Integrated Circuit Science and Engineering Hangzhou Dianzi UniversityHangzhou 310018China

An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP networks.The equivalent circuit of the gate-FP is identical to that of the intrinsic transistor.In order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the source-FP.The analytical extraction procedure of the model parameters is presented based on the proposed equivalent circuit.The verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm technology.Compared with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.

关键词： small-signal model dual field-plate(FP) GaN high-electron-mobility transistors(HEMT) parameter extraction

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Hemin-functionalized polypyrrole/paper-derived biochar electrocatalysts:Enhanced sensor platforms for H2O2

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Progress in Natural Science:Materials International 2024年第2期34卷 280-289页

作者： Yuhang jiang Tianshuang Bao Xiangchuan zhao Qi Wang Yue Cao jun Cao Xingxiang ji Weimeng Si School of Materials Science and Engineering Shandong University of Technology State Key Laboratory of Biobased Material and Green Papermaking Qilu University of Technology (Shandong Academy of Sciences)

As a H2O2electrochemical biomimetic enzyme sensor,the stability,repeatability and sensitivity of hemin-based composites are closely connected with the loading of hemin on high-performance matrix.Herein,polypyrrole/paper-derived carbon（PPy/PC） nanocomposite was used for the construction of a hemin-based non-enzymatic sensor to detect H2O2.Where the poplar wood is used to obtain crude cellulose through a straightforward papermaking process.This crude cellulose is then subjected to pyrolysis to yield the desired paper-based carbon material.The hemin-decorated PPy/PC was demonstrated possessing remarkable electrocatalytic activity for H2O2reduction,and the possible mechanism of the reactions was discussed.The electrochemical sensor,utilizing the HPPy/PC composite,achieved a low detection limit of 30 nM,along with enhanced selectivity and stability under optimized conditions.The favorable results observed can primarily be attributed to the superior electrochemical performance of PPy/PC,as well as its unique 3D interconnected structure.This structure effectively impedes the self-dimerization of hemin,thereby ensuring the generation of active catalytic species.

关键词： Biochar H2O2 sensing Hemin Paper-based carbon materials Paper-making process

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Quantitative characterizations of anisotropic dynamic properties in organic-rich shale with different kerogen content

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Petroleum Science 2024年第2期21卷 855-865页

作者： jian-Yong Xie Yan-Ping Fang Xing-Hua Wu jian'er zhao jun-Cheng Dai jun-Xing Cao ji-Xin Deng State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu610059SichuanChina Key Lab of Earth Exploration&Information Techniques of Ministry of Education Geophysical InstituteChengdu University of TechnologyChengdu610059SichuanChina PetroChina Southwest Oil&Gasfield Company Chengdu610017SichuanChina

Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore fluid.We employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying KC.These artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different directions.Observations revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of kerogen.All elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC variations.In the range of low KC(10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.

关键词： Elastic properties Organic shale Anisotropy Kerogen content Physical modeling

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Dual-Confined Bead-Like CoSe_(2)@NC@NCNFs Bifunctional Catalyst Boosting Rechargeable Zinc-Air Batteries

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Chinese Journal of Chemistry 2024年第4期42卷 397-405页

作者： Kuixing Ding jiugang Hu Liming zhao Huanan Yu Shan Cai Yi Yang jun Tan Hongshuai Hou Xiaobo ji College of Chemistry and Chemical Engineering Central South UniversityChangshaHunan410083 China College of Materials and Chemistry China Jiliang UniversityHangzhouZhejiang310018 China College of Standardization China Jiliang UniversityHangzhouZhejiang310018 China

Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe_(2)@NC@NCNFs bifunctional catalyst was designed and fabricated by confining cubic CoSe_(2)nanoparticles to three-dimensional(3D)porous MOFs-derived nitrogen-doped carbon(NC)and one-dimensional(1D)N-doped carbon nanofibers(NCNFs)through a facile encapsulate strategy.The 1D/3D continuous network structure contributes to the improvement of specific surface area and electronic conductivity,while the strong synergistic effect between CoSe_(2)sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion resistance.The as-constructed CoSe_(2)@NC@NCNFs catalyst exhibits high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V(vs.RHE)in ORR and a low overpotential of 280 mV at 10 mA·cm^(−2)in OER.More encouragingly,the rechargeable ZABs with CoSe_(2)@NC@NCNFs cathode deliver high peak power densities(126.8 mW·cm^(−2)),large specific capacities(763.1 mA·h·g^(−1)),and robust charge-discharge cycling stability over 240 cycles.This study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.

关键词： Dual-confined Electrospinning Cobalt selenide Bifunctional catalysts Rechargeable zinc-air batteries

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Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

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Science China Earth Sciences 2024年第5期67卷 1698-1713页

作者： Bing HAN Wenbao HU Guoze zhao ji TANG State Key Laboratory of Earthquake Dynamics Institute of GeologyBeijing 100029China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education Yangtze UniversityWuhan 430100China

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.

关键词： MT responses Identifying SEM anomaly Vector electric dipole responses Localizing SEM sources by inversion

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Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI Xin zhao Yanlong ZHANG ji-Feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

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Multiple exciton generation effect in photocatalytic overall water splitting

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Science China Chemistry 2024年第2期67卷 424-425页

作者： Xiaolei Guo ji-jun Zou Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China

This highlight is based on recent research published in Nature Energy by Li and co-workers [1] from Northwestern Polytechnology University, reporting an exceeding 100% internal quantum efficiency(IQE) in photocatalytic overall water splitting. This breakthrough promises a bright future for efficient photocatalyst design by utilizing the multiple exciton effect(MEG).

关键词： splitting effect utilizing

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