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Progress on statistical models of evaluating inclusions in clean steels

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Journal of Iron and Steel Research International 2022年第8期29卷 1153-1163页

作者： zheng Wang yue-hui Guan Hai-wen Luo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Jiang Yin Xing Cheng Alloy Material Co. Ltd.Jiangyin 214432JiangsuChina

Non-metallic inclusions are critical for the fatigue failure of clean steels in service;especially,the large and hard inclusions are *** it is not possible to measure all the inclusions in the large-volume clean steels,statistical models have been developed to evaluate inclusions,aiming at predicting the maximum inclusion size in the large volume from the data of inclusions,which are derived from the limited observations on small-volume *** statistical models were reviewed together with their supporting *** particular,the block maxima and the threshold types of models were discussed through a thorough comparison as they are both widely used and based on the extreme value *** predicted results not only are used to distinguish the different cleanliness levels of steels,but also help to estimate fatigue ***,future research is proposed to focus on tackling the present difficulties encountered by statistical models,including the sufficient credibility of obtained results and the robustness of models for applications.

关键词： Clean steel Maximum inclusion prediction Statistical model Extreme value theory Fatigue failure

Prodrugs of hydrogen sulfide and related sulfur species: recent development

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Chinese Journal of Natural Medicines 2020年第4期18卷 296-307页

作者： YUAN zheng-Nan zheng yue-Qin WANG Bing-He Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State UniversityAtlantaGeorgia 30303USA

Hydrogen sulfide(H2S) is commonly referred to as the third gasotransmitter with firmly established physiological roles. Prodrug approaches have been broadly applied to deliver H2S for various applications and mechanistic studies. Since S-persulfidation and glutathionylation are known to be important in cellular signaling by sulfur species, there have been interests in developing donors of persulfide and glutathione persulfide as well. In this review, we discuss the recent development in area of prodrugs for various sulfur species.

关键词： H2S S-persulfidation Light-sensitive H2S prodrugs

Phase Synchronization in Coupled Oscillators: Dynamical Manifestations

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Chinese Physics Letters 2001年第7期18卷 874-877页

作者： zheng Zhi-gang HU gang Bambi Hu Department of Physics Beijing Normal UniversityBeijing 100875 Department of Physics and Center for Nonlinear Studies Hong Kong Baptist UniversityHong Kong Department of Physics University of HoustonHouston TX77204USA

Phase synchronized entrainment of coupled oscillators with distributed natural frequencies is studied by exploring the dynamical *** route from partial to complete phase synchronization is identified as a cascade of transitions from high-to low-dimensional tori(quasiperiodicities)interrupted by intermittent *** ON-OFF intermittency is found at the onset of ***-induced chaos originates from the mixing of intermittent ON-OFF time scales.

关键词： chaos Phase chaos

Rapid detection to long ship wake in synthetic aperture radar satellite imagery

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Journal of Oceanology and Limnology 2019年第5期37卷 1523-1532页

作者： CHEN Peng LI Xiunan zheng gang Second Institute of Oceanography Ministry of Natural Resources

The maritime administrative department employs synthetic aperture radar (SAR) satellite remote sensing technology to obtain evidence of illegal discharge of ships. If the ship is discharged during navigation, it forms a long dark wake on the SAR image due to the suppression of the Bragg wave by the oil fi lm. This study investigates key techniques for rapid detection of long ship wakes, thereby providing law enforcement agencies with candidate ships for possible discharge. This paper presents a rapid long ship wake detection method that uses satellite imaging parameters and the axial direction of the ship in images to determine the potential detection area of the wake. Then, the threshold of long ship wake detection is determined using statistical analysis, the area is binarized, and isolated points are removed using a morphological filter operator. The method was tested with ENVISAT Synthetic Aperture Radar and GF-3 SAR data, and results showed that the method was eff ective, and the overall accuracy of the decision reaches 71%. We present two innovations;one is a method that draws a Doppler shift curve, and uses the SAR imaging parameters to determine the detection area of the long wake to achieve rapid detection and reduce the image detection area. The other is where a classical linear fitting method is used to quickly and accurately determine whether the detected dark area is a long ship wake and realizes the twisted long ship wake detection caused by the sea surface flow field, which is otherwise diffi cult to detect by the traditional Radon and Hough transform methods. This method has good suppression performance for the dark spot false alarm formed by low speed wind region or upward flow. The method is developed for maritime ship monitoring system and will promote the operational application of maritime ship monitoring system.

关键词： marine pollution illegal discharge linear fi t oil spill synthetic aperture radar (SAR) long ship wake

Trapping Mechanism for Long Waves over Circular Islands with Power Function Profiles

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Journal of Ocean University of China 2017年第4期16卷 655-660页

作者： zheng Jinhai FU Danjuan WANG gang State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098P.R.China College of Harbour Coastal and Offshore EngineeringHohai UniversityNanjing 210098P.R.China

Long waves such as tsunamis can be trapped by islands due to wave refraction,and these trapped waves will cause huge damage even in the sheltered shoreline of the *** all waves propagating into the topography and finally reaching the coastline are called perfect trapped modes,while any waves escaping from the topography are called leaky *** these long waves can be trapped is dependent on the depth profile of the *** paper presents analytic solutions of the ray path for waves propagating into the circular island with power function *** height distributions over the island are further investigated based on the principia that crowded rays correspond to large wave height and sparse rays correspond to small wave *** trapped mechanism for water waves over the island is revealed based on their ray ***,the perfectly trapped criterion is derived,that is,when the slope gradient at the topography toe is greater than twice the ratio of the water depth to the radial distances,all wave rays propagating on the island will finally reach the coastline,and the waves are perfectly trapped.

关键词： trapped wave circular island ray theory trapped criterion

Detection approach for unusable shared bikes enabled by reinforcement learning and PageRank algorithm

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Journal of Safety Science and Resilience 2023年第2期4卷 220-227页

作者： Yu Zhou Ran zheng gang Kou Colege of Economics and Management Inner Mongolia UniversityHohhot 010021China School of Business Administration Southwestern University of Finance and EconomicsChengdu 611130China

Existing research models can neither indicate the availability of shared bikes nor detect unusable ones owing to a lack of information on bike maintenance and *** improve awareness regarding the availability of shared bikes,we propose an innovative approach for detecting unusable shared bikes based on reinforcement learning and the PageRank *** proposed method identifies unusable shared bikes depending on the local travel data and provides a ranking of the shared bikes according to their availability *** a sliding time window,the value function for the reinforcement learning model was determined by considering the cumulative number of unavailable shared bikes,the proportion of rental cancelations at the same stations,and the mean time between the *** learning was then used to identify shared bikes with the worst *** availability ranking for the shared bikes below the reward threshold was performed using the PageRank *** proposed detection approach was applied to a trip dataset of a real-world bike-sharing system to illustrate the modeling process and its *** detection results of unusable shared bikes in the absence of failure and feedback data can provide essential information to support the maintenance management decisions regarding shared bikes.

关键词： Bike-sharing system Bike availability Maintenance Failure Shared bike Intelligent transportation Reinforcement learning PageRank algorithm Detection

Synchronized Firing in Coupled Inhomogeneous Excitable Neurons

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Communications in Theoretical Physics 2002年第10期38卷 415-420页

作者： zheng Zhi-gang WANG Fu-Zhong Department of Physics Beijing Normal University Beijing 100875 China Department of Physics Jinzhou Teachers College Jinzhou 121003 Liaoning Province China Department of Physics Jinzhou Teachers College Jinzhou 121003 Liaoning Province China

We study the firing synchronization behavior of the inhomogeneous excitable media. Phase synchronizationof neuron firings is observed with increasing the coupling, while the phases of neurons are different (out-of-phase synchronization). We found the synchronization of bursts can be greatly enhanced by applying an external forcing (in-phasesynchronization). The external forcing can be either a periodic or just homogeneous thermal noise. The mechanismresponsible for this enhancement is *** numbers: 05.45.-a, 87.10.

关键词： excitable media, phase synchronization, FitzHugh-Nagumo model

Modeling and experimental validation of vertical landing reusable launch vehicle under symmetric landing conditions

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Chinese Journal of Aeronautics 2022年第12期35卷 156-172页

作者： Shuai yue Qing LIN Guang zheng Zhonghua DU School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Aerospace System Engineering Shanghai Shanghai 201109China Key Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo 315211China

This paper illustrates the dynamic modeling,experimental validation of Reusable Launch Vehicle under symmetric landing ***,a new quasi-3D dynamic landing model of vehicle under 2-2 and 1-2-1 symmetric landing mode is established,which can predict the plane motion of the main body and the spatial motion of landing struts and *** strut force,footpad-ground contact force and the liquid spring damper are also included in the ***,the landing impact experiments are performed for 2-2 and 1-2-1 symmetric landing *** main and auxiliary strut force are obtained,along with the force-stroke diagram of *** comparing with experimental data,the accuracy of simulation model is *** is found that the simulation model possesses good match with tested responses in damping stroke and main strut *** simulation and experiment also indicate the same trend in auxiliary strut force and main body *** main discrepancies attribute to the simplified structural flexibility and nonlinear contact。

关键词： Dynamics Impact Landing gear Launch vehicle Modeling

Bifunctional Ion Pair Catalysts from Chiral a-Amino Acids

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Chinese Journal of Chemistry 2019年第11期37卷 1111-1119页

作者： Hongyu Wang Changwu zheng gang Zhao Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China College of Chemistry Chemical Engineering and Materials ScienceShandong Normal UniversityJinanShandong 250014China School of Pharmacy Shanghai University of Traditional Chinese MedicineShanghai 201203China

What is the most favorite and original chemistry developed in your research group?Our research focuses on the field of asymmetric organocatalysis and natural product *** work draws upon and impacts the design and synthesis of N-and P-containing bifunctional ion pair catalysts from a-amino acids,and their applications as organocatalysts or ligands in asymmetric synthesis.

关键词： synthesis. asymmetric organo