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Debris Flow Susceptibility Evaluation in Meizoseismal Region:A Case Study in Jiuzhaigou,China

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Journal of Earth Science 2024年第1期35卷 263-279页

作者： yongwei Li Linrong Xu Yonghui Shang Shuyang Chen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-Speed Railway Construction Technology Central South UniversityChangsha 410075China School of Civil Engineering Central South University of Forestry and TechnologyChangsha 410004China

Jiuzhaigou is situated on a mountain-canyon region and is famous for frequent tectonic *** abundance of loose co-seismic landslides and collapses were produced on gullies after the Jiuzhaigou Earthquake on August 8,2.17,which was served as material source for debris flow in later *** flow appears frequently which are seriously endangering the safety of people's lives and *** the earliest debris flow appeared in areas where no case ever reported *** debris flow susceptibility evaluation(DFSE)is used for predicting the areas prone to debris flow,which is urgently required to avoid hazards and help to guide the strategy of preventive ***,this work employs debris flow in Jiuzhaigou to reveal the characteristics of disaster-pregnant environment and to explore the application of machine learning in *** new viewpoints are suggested:(i)Material density factor of debris flow is first adopted in this work,and it is proved to be a critical factor for triggering debris flows by sensitivity analysis method.(ii)Deep neural network and convolutional neural network(CNN)achieve relatively good area under the curve(AUC)values and are 0.02.-0.02. higher than traditional machine learning methods.(iii)Watershed units combined with CNNbased model can achieve more accurate,reliable and practical susceptibility *** work provides an idea for prevention of debris flow in mountainous lands.

关键词： machine learning earthquakes debris flow susceptibility convolutional neural network deep neural network watershed unit

Orthogonal waveform design with fractional programming on the ambiguity suppression of SAR systems

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Science China(Information Sciences) 2024年第9期67卷 263-279页

作者： Yunkai DENG yongwei ZHANG Zhimin ZHANG Wei WANG Heng ZHANG Department of Space Microwave Remote Sensing System Aerospace Information Research InstituteChinese Academy of Sciences

Waveform diversity(WD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, WD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar(SAR) *** these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density(PSD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio(CAR) and satisfactory imaging performance. Initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PSD variable, which sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PSD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in SAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization SAR systems.

关键词： synthetic aperture radar (SAR) waveform diversity (WD) ambiguity suppression orthogonal waveform fractional programming power spectrum density (PSD)

Simulation of Two-Phase Flowback Phenomena in Shale Gas Wells

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Fluid Dynamics & Materials Processing 2024年第2期20卷 349-364页

作者： yongwei Duan Zhaopeng Zhu Hui He Gaoliang Xuan Xuemeng Yu Oil Gas Engineering Research Institute PetroChina Jilin OilfieldSongyuan138000China

The gas-water two-phaseﬂow occurring as a result of fracturingﬂuidﬂowback phenomena is known to impact signiﬁcantly the productivity of shale gas *** this work,this two-phaseﬂow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model(EDFM).This model assumes the region outside the stimulated reservoir volume(SRV)as a single-medium while the SRV region itself is described using a double-medium strategy which can account for theﬂuid exchange between the matrix and the *** shale gas adsorption,desorption,diffusion,gas slippage effect,fracture stress sensitivity,and capillary imbibition have been *** shale gas production,pore pressure distribution and water saturation distribution in the reservoir have been *** inﬂuences of hydraulic fracture geometry and nonorthogonal hydraulic fractures on gas production have been determined and discussed *** simulation results show that the daily gas production has an upward and downward trend due to the presence of a large amount of fracturingﬂuid in the reservoir around the hydraulic *** smaller the angle between the hydraulic fracture and the wellbore,the faster the daily production of shale gas wells decreases,and the lower the cumulative *** fractures can increase the control volume of hydraulic fractures and improve the production of shale gas wells.

关键词： Shale gas fracturingﬂuid backﬂow the stimulated reservoir volume gas-water two-phase production

Intravascular photoacoustic and optical coherence tomography imaging dual-mode system for detecting spontaneous coronary artery dissection: A feasibility study

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Journal of Innovative Optical Health Sciences 2024年第1期17卷 77-86页

作者： yongwei Wang Yuyang Wan Zhongjiang Chen MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science South China Normal University Guangzhou 510631P.R.China College of Biophotonics South China Normal University Guangzhou 510631 P.R.China School of Medical Technology and Engineering Fujian Medical University Fuzhou 350004 P.R.China

In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary artery dissection(SCAD)*** provides high-resolution and high-penetration images of intramural hematoma(IMH)at different depths,so it is especially useful for imaging deep blood clots associated with imaging *** can readily visualize the double-lumen morphology of blood vessel walls to identify intimal *** also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine *** results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.

关键词： Spontaneous coronary artery dissection(SCAD) intravascular optical coherence tomography(IVOCT) intravascular photoacoustic imaging(IVPAI)

Downstream Competition and Upstream Innovation:Theory and Evidence from China

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China Finance and Economic Review 2024年第1期13卷 67-87页

作者： Jing Dai Guanchun Liu Ziqi Ye Haiou Mao yongwei Ye School of Finance Hubei University of Economics Lingnan College Sun Yatsen University School of Business Administration Zhongnan University of Economics and Law College of Economics and Management Huazhong Agricultural University School of Public Economics and Management Shanghai University of Finance and Economics

Competition is the catalyst of corporate innovation,which is the foundation of a country's core *** the view of vertical industrial chain,this paper examines how downstream competition affects upstream firms'innovation *** innovation helps reduce the production cost of each product,increasing demand of intermediate products caused by downstream competition enhances the marginal revenue of upstream firms'innovation,thus leading to an innovation incentive *** identify causality,we utilize China's WTO accession,a quasinatural experiment,to calculate downstream competition combined with import tariff reduction and input-output table,and then run a difference-in-difference *** the data of Annual Survey of Industrial Firms and State Intellectual Property Office,our results find that downstream competition has a significantly positive impact on upstream firms'innovation,and this effect is more pronounced in firms with less industry competition,greater initial innovation capacity and weaker financial ***,the number of firms,the degree of industry competition and the scale of intermediate products in the downstream sector increase,confirming the market size *** sum,our findings document that downstream competition can motivate upstream firms to innovate through vertical industrial chain,providing some useful insights for China to build a fair market competition environment and promote innovation-driven growth regime.

关键词： downstream competition upstream firms'innovation vertical industrial chain market size effect

Mechanism of the electromagnetic force to control hydrodynamic noise from an airfoil model and its action mode

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Chinese Journal of Acoustics 2024年第2期43卷 173-198页

作者： LIU yongwei WANG Lu QIN Qikai ZHENG Penghui SHANG Dejiang National Key Laboratory of Underwater Acoustic Technology Harbin Engineering UniversityHarbin 150001 Key Laboratory of Marine Information Acquisition and Security(Harbin Engineering University) Ministry of Industry and Information TechnologyHarbin 150001 College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001

A method is proposed to control the flow and reduce the hydrodynamic noise by applying the constant electromagnetic force into the boundary layer. The flow and sound fields from an airfoil model with and without the electromagnetic force are calculated. Results show that along the flow direction, electromagnetic force can delay the flow separation on the airfoil surface, suppress small discrete vortices, reduce turbulent fluctuation pressure on the airfoil surface, and decrease the hydrodynamic noise. The change law of the hydrodynamic noise effect reduced by the electromagnetic force is summarized in terms of the Reynolds number, attack angle, and electromagnetic effective *** on the numerical calculation results, an actual model is experimentally measured in the water circulating tank to validate the abovementioned effect. Since the transition area pressure of the airfoil model is the lowest and the area is limited, the application of electromagnetic force into this area can achieve the lowest noise effect and decrease the power consumption. The effect of the magnetic leak is analyzed. The results provide a new method for the suppression of hydrodynamic noise in airfoil models.

关键词： airfoil noise flow

Gypenosides ameliorate morphine-induced immunosuppression with an increased proportion of thymic T lymphocyte subsets and are involved in the regulation of the cAMP-CREM/CREB-IL-2.pathway

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Genes & Diseases 2024年第3期11卷 120-123页

作者： Hui Wang Zhonghao Li Qisheng Wang Weixin Lin Ziting Zhou Xinru Mu yongwei Jiang Shengfeng Lu Shaodong Chen Zhigang Lu Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine in Prevention and Treatment of Tumor Nanjing University of Chinese MedicineNanjingJiangsu 210023China Key Laboratory of Acupuncture and Medicine Research of Ministry of Education Nanjing University of Chinese MedicineNanjingJiangsu 210023China College of Pharmacy Nanjing University of Chinese MedicineNanjingJiangsu 210023China School of Medicine Xiamen UniversityXiamenFujian 361102China

Opioid abuse can suppress the lymphatic system function,and produce severe immunosuppression that poses a significant risk of opportunistic infections such as methicillinresistant Staphylococcus aureus(MRSA)pneumonia.^(1,2.Gypenosides(Gps)are the most important immunomodulator components in the Chinese herbal medicine Gynostemma pentaphyllum.

关键词： herbal Gypenosides immunosuppression

Cambricon-QR:a sparse and bitwise reproducible quantized training accelerator

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High Technology Letters 2024年第1期30卷 52-60页

作者：李楠 ZHAO yongwei ZHI Tian LIU Chang DU Zidong HU Xing LI Wei ZHANG Xishan LI Ling SUN Guangzhong School of Computer Science and Technology University of Science and Technology of ChinaHefei 230026P.R.China State Key Laboratory of Processors Institute of Computing TechnologyChinese Academy of SciencesBeijing 100086P.R.China Cambricon Tech.Ltd Beijing 100191P.R.China Institute of Software Chinese Academy of SciencesBeijing 100086P.R.China

Quantized training has been proven to be a prominent method to achieve deep neural network training under limited computational *** uses low bit-width arithmetics with a proper scaling factor to achieve negligible accuracy ***-Q is the ASIC design proposed to efficiently support quantized training,and achieves significant performance ***,there are still two caveats in the ***,Cambricon-Q with different hardware specifications may lead to different numerical errors,resulting in non-reproducible behaviors which may become a major concern in critical ***,Cambricon-Q cannot leverage data sparsity,where considerable cycles could still be squeezed *** address the caveats,the acceleration core of Cambricon-Q is redesigned to support fine-grained irregular data *** new design not only enables acceleration on sparse data,but also enables performing local dynamic quantization by contiguous value ranges(which is hardware independent),instead of contiguous addresses(which is dependent on hardware factors).Experimental results show that the accuracy loss of the method still keeps negligible,and the accelerator achieves 1.61×performance improvement over Cambricon-Q,with about 10%energy increase.

关键词： quantized training sparse accelerator Cambricon-QR

Highly Sensitive Ammonia Gas Sensors at Room Temperature Based on the Catalytic Mechanism of N,C Coordinated Ni Single-Atom Active Center

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Nano-Micro Letters 2024年第12期16卷 515-531页

作者： Wenjing Quan Jia Shi Min Zeng Wen Lv Xiyu Chen Chao Fan yongwei Zhang Zhou Liu Xiaolu Huang Jianhua Yang Nantao Hu Tao Wang Zhi Yang National Key Laboratory of Advanced Micro and Nano Manufacture Technology Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Department of Micro/Nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Shanghai Key Laboratory of Intelligent Sensing and Detection Technology School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237People’s Republic of China

Significant challenges are posed by the limitations of gas sensing mechanisms for trace-level detection of ammonia(NH3).In this study,we propose to exploit single-atom catalytic activation and targeted adsorption properties to achieve highly sensitive and selective NH3 gas ***,Ni singleatom active sites based on N,C coordination(Ni-N-C)were interfacially confined on the surface of two-dimensional(2.)MXene nanosheets(Ni-N-C/Ti_(3)C_(2.Tx),and a fully flexible gas sensor(MNPE-Ni-N-C/Ti_(3)C_(2.Tx)was *** sensor demonstrates a remarkable response value to 5 ppm NH3(2..3%),excellent selectivity for NH3,and a low theoretical detection limit of 12.1 *** analysis by density functional calculation reveals that the Ni single-atom center with N,C coordination exhibits specific targeted adsorption properties for ***,its catalytic activation effect effectively reduces the Gibbs free energy of the sensing elemental reaction,while its electronic structure promotes the spill-over effect of reactive oxygen species at the gas-solid *** sensor has a dual-channel sensing mechanism of both chemical and electronic sensitization,which facilitates efficient electron transfer to the 2. MXene conductive network,resulting in the formation of the NH3 gas molecule sensing ***,the passivation of MXene edge defects by a conjugated hydrogen bond network enhances the long-term stability of MXene-based electrodes under high humidity *** work achieves highly sensitive room-temperature NH3 gas detection based on the catalytic mechanism of Ni single-atom active center with N,C coordination,which provides a novel gas sensing mechanism for room-temperature trace gas detection research.

关键词： Gas sensor Single atom Catalytic activation Targeted adsorption End-sealing passivation