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Reinforcement learning based adaptive control for uncertain mechanical systems with asymptotic tracking

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Defence Technology（防务技术） 2024年第4期34卷 19-28页

作者： Xiang-long Liang Zhi-kai yao yao-wen Ge Jian-yong yao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China College of Automation&College of Artificial Intelligence Nanjing University of Post and TelecommunicationNanjing210023China

This paper mainly focuses on the development of a learning-based controller for a class of uncertain mechanical systems modeled by the Euler-Lagrange formulation.The considered system can depict the behavior of a large class of engineering systems,such as vehicular systems,robot manipulators and satellites.All these systems are often characterized by highly nonlinear characteristics,heavy modeling uncertainties and unknown perturbations,therefore,accurate-model-based nonlinear control approaches become unavailable.Motivated by the challenge,a reinforcement learning(RL)adaptive control methodology based on the actor-critic framework is investigated to compensate the uncertain mechanical dynamics.The approximation inaccuracies caused by RL and the exogenous unknown disturbances are circumvented via a continuous robust integral of the sign of the error(RISE)control approach.Different from a classical RISE control law,a tanh(·)function is utilized instead of a sign(·)function to acquire a more smooth control signal.The developed controller requires very little prior knowledge of the dynamic model,is robust to unknown dynamics and exogenous disturbances,and can achieve asymptotic output tracking.Eventually,co-simulations through ADAMS and MATLAB/Simulink on a three degrees-of-freedom(3-DOF)manipulator and experiments on a real-time electromechanical servo system are performed to verify the performance of the proposed approach.

关键词： Adaptive control Reinforcement learning Uncertain mechanical systems Asymptotic tracking

Recent advances in promising drugs for primary prevention of gastroesophageal variceal bleeding with cirrhotic portal hypertension

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 4-13页

作者： Ji-yao Sheng Zi-Fan Meng Qiao Li yong-Sheng Yang Department of Hepatobiliary and Pancreatic Surgery the Second Hospital of Jilin UniversityChangchun 130041China Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases the Second Hospital of Jilin UniversityChangchun 130041China

Background:Gastroesophageal variceal bleeding is one of the most severe complications of patients with cirrhosis.Although primary prevention drugs,including non-selectiveβ-blockers,have effectively reduced the incidence of bleeding,their efficacy is limited due to side effects and related contraindications.With recent advances in precision medicine,precise drug treatment provides better treatment efficacy.Data sources:Literature search was conducted in PubMed,MEDLINE and Web of Science for relevant articles published up to May 2022.Information on clinical trials was obtained from https://clinicaltrials.gov/and http://***/.Results:The in-depth understanding of the pathogenesis and advances of portal hypertension has enabled the discovery of multiple molecular targets for promising drugs.According to the site of action,these drugs could be classified into four classes:intrahepatic,extrahepatic,both intrahepatic and extrahepatic targets and others.All these classes of drugs offer advantages over traditional treatments in prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.Conclusions:This review classified and summarized the promising drugs,which prevent gastroesophageal variceal bleeding by targeting specific markers of pathogenesis of portal hypertension,demonstrating the significance of using the precision medicine strategy to discover and develop promising drugs for the primary prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.

关键词： Cirrhotic portal hypertension Target drug Primary prevention Bleeding

Design,synthesis,and biological evaluation of novel chrysin derivatives as poly(ADP-ribose)polymerase 1(PARP1)inhibitors for the treatment of breast cancer

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Chinese Journal of Natural Medicines 2024年第5期22卷 455-465页

作者： YANG yao TONG Jing XIE Xianshun CAO Hong FU yong LUO yong LIU Shan CHEN Wen YANG Ning Hengyang Medical School University of South ChinaHengyang 421200China Emergency Department Hengyang Medical SchoolThe Second Affiliated HospitalUniversity of South ChinaHengyang 421200China Hengyang Medical School The Second Affiliated HospitalUniversity of South ChinaHengyang 421200China Hemato-oncology Department Hengyang Medical SchoolThe Second Affiliated HospitalUniversity of South ChinaHengyang 421200China Department of Breast and Thyroid Surgery Hengyang Medical SchoolThe Second Affiliated HospitalUniversity of South ChinaHengyang 421200China

In this study,we reported the discovery and structure-activity relationship analysis of chrysin derivatives as a new class of inhibitors targeting poly(ADP-ribose)polymerase 1(PARP1).Among these derivatives,compound 5d emerged as the most effective chrysin-based inhibitor of PARP1,with an IC50 value of 108 nmol·L^(-1).This compound significantly inhibited the proliferation and migration of breast cancer cell lines HCC-1937 and MDA-MB-436 by inducing DNA damage.Furthermore,5d induced apoptosis and caused an extended G1/S-phase in these cell lines.Molecular docking studies revealed that 5d possesses a strong binding affinity toward PARP1.In vivo,in a xenograft model,5d effectively reduced tumor growth by downregulating PARP1 expression.Overall,compound 5d shows promise as a potential therapeutic agent for the treatment of BRCA wild-type breast cancer.

关键词： Chrysin derivatives PARP1 Antitumor DNA damage Small molecules

Impact of letters to the editor and publications in 2023

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Zoological Research 2024年第1期45卷 136-137页

作者： Xiu-Ping Zhang Xue-Long Jiang yong-Gang yao Editorial Office of ZR&ZRDC Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China

A letter to the editor constitutes a short communication addressing a range of topics pertinent to the readership of a journal(Dkhar,2018).This format offers several benefits,such as timeliness,accessibility,innovation,and conciseness,thereby serving as an effective means to disseminate cuttingedge scientific ideas.Over the past five years,there has been a considerable increase in the number of letters published,representing the highest growth rate(approximately 20%)observed in the last three decades(Figure 1A).In the field of academic publishing,letters to the editor are typically more concise than typical research papers.

关键词： journal editor Figure

The homogenous growth of Co-based coordination compound on graphene nanosheet for high-performance K-organic battery and its reaction mechanism

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Rare Metals 2024年第4期43卷 1622-1634页

作者： Qian-Qian Peng Yi-Ting Wang Shuo Qi yao Xiao yong Wang Shuang-Qiang Chen School of Environmental and Chemical Engineering Shanghai University School of Chemistry and Materials Engineering Wenzhou University

Metal coordination compounds（MCCs） are gaining popularity for potassium-ion batteries（PIBs）owing to their tuneable structure,multiple reaction sites,low cost and unique morphology.However,they are generally subjected to intrinsic features of the sluggish ionic diffusion coefficient,low electronic conductivity and slow kinetics.Herein,a new MCC material of cobalt-1,3,5-trioxy-2,4,6-triamino-benzo（Co-TB） coordination compound was synthesized and homogenously grown on the surface of graphene nanosheets（GNS）,forming a Co-TB@GNS composite with enhanced electronic conductivity and flexible capability.Benefiting from the overall enhanced conductivity,high surface area and abundant activated K-storage sites,Co-TB@GNS electrodes have exhibited superior cycling performance with high reversible capacities(312 mAh·g-1after 100 cycles at 100 mA·g-1,224 mAh·g-1after 500 cycles at 1 A·g-1) and better rate performances compared with the pure Co-TB compound when served as PIB's anodes.Furthermore,multiple in-situ measurement techniques have jointly confirmed that the organic functional groups（C=O,C=N and C=C of benzene rings） and Co2+in Co-TB are the main reversible K-storage sites,including in-situ Fourier transform infrared spectroscopy（FTIR） and X-ray diffraction（XRD）,and partial capacity contribution is originated from GNS by the apparent K-storage behavior in the in-situ XRD pattern,proving the possibility of K-storage for metal-organic materials.

关键词： Metal coordination compounds Potassium-ion battery Cobalt coordination compound K-storage mechanism

Improved forecasting via physics-guided machine learning as exemplified using“21·7”extreme rainfall event in Henan

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Science China Earth Sciences 2024年第5期67卷 1652-1674页

作者： Qi ZHONG Zhicha ZHANG Xiuping yao Shaoyu HOU Shenming FU yong CAO Linguo JING China Meteorological Administration Training Center Beijing 100081China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Zhejiang Meteorological Observatory Hangzhou 310017China Hebei Provincial Weather Modification Center Shijiazhuang 050020China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China National Meteorological Center Beijing 100081China School of Computer Science Chengdu University of Information TechnologyChengdu 610225China

As a natural disaster,extreme precipitation is among the most destructive and influential,but predicting its occurrence and evolution accurately is very challenging because of its rarity and uniqueness.Taking the example of the“21·7”extreme precipitation event(17–21 July 2021)in Henan Province,this study explores the potential of using physics-guided machine learning to improve the accuracy of forecasting the intensity and location of extreme precipitation.Three physics-guided ways of embedding physical features,fusing physical model forecasts and revised loss function are used,i.e.,(1)analyzing the anomalous circulation and thermodynamical factors,(2)analyzing the multi-model forecast bias and the associated underlying reasons for it,and(3)using professional forecasting knowledge to design the loss function,and the corresponding results are used as input for machine learning to improve the forecasting accuracy.The results indicate that by learning the relationship between anomalous physical features and heavy precipitation,the forecasting of precipitation intensity is improved significantly,but the location is rarely adjusted and more false alarms appear.Possible reasons for this are as follows.The anomalous features used here mainly contain information about large-scale systems and factors which are consistent with the model precipitation deviation;moreover,the samples of extreme precipitation are sparse and so the algorithm used here is simple.However,by combining“good and different”multi models with machine learning,the advantages of each model are extracted and then the location of the precipitation center in the forecast is improved significantly.Therefore,by combining the appropriate anomalous features with multi-model fusion,an integrated improvement of the forecast of the rainfall intensity and location is achieved.Overall,this study is a novel exploration to improve the refined forecasting of heavy precipitation with extreme intensity and high variability,and provides a reference for the deep fusion of

关键词： Extreme precipitation event Refined assessment Anomalous physical features Multi-model fusion Machine learning

Association between Serum Ferritin Levels and Metabolic-associated Fatty Liver Disease in Adults:a Cross-sectional Study Based on the NHANES

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Current Medical Science 2024年第3期44卷 494-502页

作者： Jiang-hui LI Xue-yao MA Yun YI Lu-rao LI Zhi-yong XU Ying CHANG Department of Gastroenterology Zhongnan Hospital of Wuhan UniversityWuhan430071China Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases Wuhan430071China Endoscopy Center The People’s Hospital of YingshanHuanggang438799China

Objective Ferritin,initially acting as an iron-storage protein,was found to be associated with metabolic diseases.Our study was designed to investigate the association between serum ferritin and metabolic-associated fatty liver disease(MAFLD)using data from the National Health and Nutrition Examination Survey(NHANES)of the United State of America.Methods A cross-sectional study was conducted,enrolling a total of 2145 participants from the NHANES in the 2017–2018 cycles.Hepatic steatosis and liver fibrosis were assessed by ultrasound images and several non-invasive indexes.Multiple regression analysis was conducted to determine the associations between serum ferritin concentration and MAFLD and liver fibrosis.Results The analysis revealed that participants with higher serum ferritin levels(Q3 and Q4 groups)had a higher prevalence of MAFLD than those with the lowest serum ferritin levels[Q3 vs.Q1:OR=2.17(1.33,3.53),P<0.05 in fatty liver index(FLI);Q4 vs.Q1:OR=3.13(1.91,5.13),P<0.05 in FLI].Additionally,participants with the highest serum ferritin levels(Q4 group)displayed a higher prevalence of liver fibrosis[Q4 vs.Q1:OR=2.59(1.19,5.62),P<0.05 in liver stiffness measurement;OR=5.06(1.12,22.94),P<0.05 in fibrosis-4 index],with significantly increased risk observed in participants with concomitant diabetes[OR=7.45(1.55,35.72),P=0.012].Conclusion Our study revealed that elevated serum ferritin levels are associated with a higher prevalence of MAFLD and advanced liver fibrosis in patients.Elevated serum ferritin levels combined with diabetes are important risk factors for liver fibrosis.

关键词： serum ferritin liver fibrosis metabolic-associated fatty liver disease National Health and Nutrition Examination Survey

Fracture geometry and breakdown pressure of radial borehole fracturing in multiple layers

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Petroleum Science 2024年第1期21卷 430-444页

作者： Yu-Ning yong Zhao-Quan Guo Shou-Ceng Tian Lu-yao Ma Tian-Yu Wang Mao Sheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Beijing Petroleum Machinery Company Limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smart Energy Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

Radial borehole fracturing that combines radial boreholes with hydraulic fracturing is anticipated to improve the output of tight oil and gas reservoirs.This paper aims to investigate fracture propagation and pressure characteristics of radial borehole fracturing in multiple layers.A series of laboratory experiments with artificial rock samples(395 mm×395 mm×395 mm)was conducted using a true triaxial fracturing device.Three crucial factors corresponding to the vertical distance of adjacent radial borehole layers(vertical distance),the azimuth and diameter of the radial borehole are examined.Experimental results show that radial borehole fracturing in multiple layers generates diverse fracture geometries.Four types of fractures are identified based on the connectivity between hydraulic fractures and radial boreholes.The vertical distance significantly influences fracture propagation perpendicular to the radial borehole axis.An increase in the vertical distance impedes fracture connection across multiple radial borehole layers and reduces the fracture propagation distance along the radial borehole axis.The azimuth also influences fracture propagation along the radial borehole axis.Increasing the azimuth reduces the guiding ability of radial boreholes,which makes the fracture quickly curve to the maximum horizontal stress direction.The breakdown pressure correlates with diverse fracture geometries observed.When the fractures connect multi-layer radial boreholes,increasing the vertical distance decreases the breakdown pressure.Decreasing the azimuth and increasing the diameter also decrease the breakdown pressure.The extrusion force exists between the adjacent fractures generated in radial boreholes in multiple rows,which plays a crucial role in enhancing the guiding ability of radial boreholes and results in higher breakdown pressure.The research provides valuable theoretical insights for the field application of radial borehole fracturing technology in tight oil and gas reservoirs.

关键词： Multi-layer radial boreholes Hydraulic fracturing Fracture propagation Pressure characteristic

Regulation of the quantum barrier and carrier transport toward high-efficiency quasi-2D Dion-Jacobson tin perovskite solar cells

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Journal of Energy Chemistry 2024年第8期95卷 200-207页

作者： Huanhuan yao Chang Shi Tai Wu Shurong Wang Mingyu Yin Liming Ding yong Hua Feng Hao School of Materials and Energy University of Electronic Science and Technology of China College of Chemistry and Molecular Engineering Peking University Yunnan Key Laboratory for Micro/Nano Materials & Technology School of Materials and Energy Yunnan University Center for Excellence in Nanoscience (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS) National Center for Nanoscience and Technology

Quasi-2D Dion-Jacobson（DJ） tin halide perovskite has attracted much attention due to its elimination of Van der Waals gap and enhanced environmental stability.However,the bulky organic spacers usually form a natural quantum well structure,which brings a large quantum barrier and poor film quality,further limiting the carrier transport and device performance.Here,we designed three organic spacers with different chain lengths(ethylenediamine（EDA）,1,3-propanediamine（PDA）,and 1,4-butanediamine（BDA）) to investigate the quantum barrier dependence.Theoretical and experimental characterizations indicate that EDA with short chain can reduce the lattice distortion and dielectric confinement effect,which is beneficial to the effective dissociation of excitons and the inhibition of trap-free non-radiative relaxation.In addition,EDA cation shows strong interaction with the inorganic octahedron,realizing large aggregates in precursor solution and high-quality films with improved structural stability.Furthermore,femtosecond transient absorption proves that EDA cations can also weaken the formation of small n-phases with large quantum barrier to achieve effective carrier transport between different nphases.Finally,the quasi-2D DJ（EDA）FA9Sn10I31solar cells achieves a 7.07% power conversion efficiency with good environment stability.Therefore,this work sheds light on the regulation of the quantum barrier and carrier transport through the chain length of organic spacer for qua si-2D DJ lead-free perovskites.

关键词： Carrier transport Chain lengths Lattice distortion Organic spacers Quantum well