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Aerodynamic Performance of Three Flapping wings with Unequal Spacing in Tandem Formation

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Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： Min Chang Ziyi Xu Zengshuang Chen li li Xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation

Association of accelerometer-measured sleep duration and different intensities of physical activity with incident type 2 diabetes in a population-based cohort study

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Journal of Sport and Health Science 2024年第2期13卷 222-232页

作者： Xinyi Jin Yilin Chen Hongliang Feng Mingqing Zhou Joey W.Y.Chang Yaping liu Alice Pik Shan Kong Xiao Tan Yun-Kwok wing Yannis Yan liang Jihui Zhang Guangdong Cardiovascular Institute Guangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhou 510080China Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention Guangdong Cardiovascular InstituteGuangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou 510080China School of Medicine South China University of TechnologyGuangzhou 510641China Center for Sleep and Circadian Medicine The Affiliated Brain Hospital of Guangzhou Medical UniversityGuangzhou 510180China The Second School of Clinical Medicine Southern Medical UniversityGuangzhou 510282China Guangdong Mental Health Center Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou 510120China li Chiu Kong Family Sleep Assessment Unit Department of PsychiatryFaculty of MedicineThe Chinese University of Hong KongHong Kong 999077China Department of Psychiatry Faculty of MedicineThe Chinese University of Hong KongHong Kong 999077China Department of Medicine and Therapeutics Faculty of MedicineThe Chinese University of Hong KongHong Kong 999077China Department of Medical Sciences Uppsala UniversityUppsala 75185Sweden Department of Big Data in Health Science Zhejiang University School of Public HealthHangzhou 310058China Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China Guangzhou 510260China

Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort ***:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK *** duration(short:8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and *** was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death ***:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were *** with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes *** increased risk among short sleepers seems to be protected against by *** with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did ***:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk.

关键词： light physical activity Sleep duration Triaxial accelerometer Type 2 diabetes UK Biobank

An Evaluation of Tropical Cyclone Genesis Forecast over the Western North Pacific and the South China Sea from the CMA-TRAMS

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Journal of Tropical Meteorology 2024年第1期30卷 20-28页

作者：李梦婕陈子通戴光丰田群梁卓轩林青张艳霞 Guangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction CMAGuangzhou 510641 China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081 China Guangdong Meteorological Observatory Guangzhou 510641 China

Tropical cyclone(TC) genesis forecasting is essential for daily operational practices during the typhoon *** updated version of the Tropical Regional Atmosphere Model for the South China Sea(CMA-TRAMS) offers forecasters reliable numerical weather prediction(NWP) products with improved configurations and fine resolution. While traditional evaluation of typhoon forecasts has focused on track and intensity, the increasing accuracy of TC genesis forecasts calls for more comprehensive evaluation methods to assess the reliability of these predictions. This study aims to evaluate the effectiveness of the CMA-TRAMS for cyclogenesis forecasts over the western North Pacific and South China Sea. Based on previous research and typhoon observation data over five years, a set of localized, objective criteria has been proposed. The analysis results indicate that the CMA-TRAMS demonstrated superiority in cyclogenesis forecasts, predicting 6 out of 22 TCs with a forecast lead time of up to 144 h. Additionally, over 80% of the total could be predicted 72 h in advance. The model also showed an average TC genesis position error of 218.3 km, comparable to the track errors of operational models according to the annual evaluation. The study also briefly investigated the forecast of Noul(2011). The forecast field of the CMA-TRAMS depicted thermal and dynamical conditions that could trigger typhoon genesis, consistent with the analysis field. The 96-hour forecast field of the CMA-TRAMS displayed a relatively organized threedimensional structure of the typhoon. These results can enhance understanding of the mechanism behind typhoon genesis,fine-tune model configurations and dynamical frameworks, and provide reliable forecasts for forecasters.

关键词： CMA-TRAMS cyclogenesis numerical weather prediction tropical cyclone

Circadian rhythm dysfunction and psychopathology in the offspring of parents with bipolar disorder:a highrisk study in the Chinese population

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General Psychiatry 2024年第3期37卷 388-400页

作者： Binbin Lei Hongliang Feng Lulu Yang Jing Wang Jie Chen Weidong Song Chao Jiang Kun Zhang Qunfeng Wang Jessie Chi Ching Tsang Ngan Yin Chan Yaping liu Joey W.Y.Chan Jiyang Pan Bin Zhang Tao li Kathleen Ries Merikangas Jihui Zhang Yun Kwok wing Guangdong Cardiovascular Institute Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouGuangdongChina Guangdong Mental Health Center Guangdong Provincial People's Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhouGuangdongChina li Chiu Kong Family Sleep Assessment Unit Department of PsychiatryFaculty of MedicineThe Chinese University of Hong KongHong KongChina Center for Sleep and Circadian Medicine The Affiliated Brain Hospital of Guangzhou Medical UniversityGuangzhouGuangdongChina Department of Psychiatry Faculty of MedicineThe Chinese University of Hong KongNew TerritoriesHong KongChina Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China Guangzhou Medical UniversityGuangzhouGuangdongChina Shenzhen Nanshan Center for Chronic Diseases Control(Shenzhen Nanshan Mental Health Center) ShenzhenChina Department of Clinical Psychology Shenzhen Fuyong People's HospitalShenzhenChina Department of Mental Illness Prevention and Treatment Shenzhen Longgang Center for Chronic Diseases ControlShenzhenChina Department of Neurology Zhongnan Hospital of Wuhan UniversityWuhanHubeiChina Sleep Medical Center The First Affiliated Hospital of Jinan UniversityGuangzhouGuangdongChina Department of Psychiatry Nanfang HospitalSouthern Medical UniversityGuangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired IntelligenceGuangzhouGuangdongChina Department of Neurobiology Affiliated Mental Health Center&Hangzhou Seventh People's HospitalZhejiang University School of MedicineHangzhouZhejiangChina Genetic Epidemiology Research Branch Intramural Research ProgramNational Institute of Mental HealthBethesdaMarylandUSA

Background Understanding the evolution of circadian rhythm dysfunction and psychopathology in the high-risk population has important implications for the prevention of bipolar ***,some of the previous studies on the emergence of psychopathologies and circadian dysfunction among high-risk populations were inconsistent and *** To examine the prevalence rates of sleep and circadian dysfunctions,mental disorders and their symptoms in the offspring of parents with(O-BD)and without bipolar disorder(O-control).Methods The study included 191 O-BD and 202 O-control subjects aged 6-21 years from the Greater Bay Area,*** diagnoses and symptoms of sleep/circadian rhythm and mental disorders were assessed by the Diagnostic Interview for Sleep Patterns and Disorders,and the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and lifetime Version,*** estimating equations and shared frailty proportional hazards models of survival analysis were applied to compare the outcomes in the *** Adjusting for age,sex and region of recruitment,there was a significantly higher risk of delayed sleep phase symptoms(9.55%vs 2.58%,adjusted OR:4.04)in O-BD than in O-control.O-BD had a nearly fivefold higher risk of mood disorders(11.70%vs 3.47%,adjusted OR:4.68)and social anxiety(6.28%vs 1.49%,adjusted OR:4.70),a fourfold higher risk of depressive disorders(11.17%vs 3.47%,adjusted OR:3.99)and a threefold higher risk of mood symptoms(20.74%vs 10.40%,adjusted OR:2.59)than *** analysis revealed that O-BD children(aged under 12 years)had a nearly 2-fold higher risk of any mental and behavioural symptoms than O-control,while there was a nearly 4-fold higher risk of delayed sleep phase symptoms,a 7.5-fold higher risk of social anxiety and a 3-fold higher risk of mood symptoms in O-BD adolescents(aged 12 years and over).Conclusions There was an increase in delayed sleep phase symptoms in O-BD

关键词： prevention dysfunction bipolar

Gut Microbiome in Colorectal Cancer:Clinical Diagnosis and Treatment

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Genomics, Proteomics & Bioinformatics 2023年第1期21卷 84-96页

作者： Yali liu Harry cheuk-Hay Lau wing Yin Cheng Jun Yu Institute of Digestive Disease and The Department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseLi Ka Shing Institute of Health SciencesCUHK Shenzhen Research InstituteThe Chinese University of Hong KongHong Kong Special Administrative Region 999077China

Colorectal cancer(CRC)is one of the most frequently diagnosed cancers and the leading cause of cancer-associated *** studies have shown that both genetic and environmental risk factors contribute to the development of *** metagenomic studies of CRC have identified gut dysbiosis as a fundamental risk factor in the evolution of colorectal *** enormous efforts and substantial progresses have been made in understanding the relationship between human gut microbiome and CRC,the precise mechanisms involved remain *** data have shown a direct causative role of the gut microbiome in DNA damage,inflammation,and drug resistance in CRC,suggesting that modulation of gut microbiome could act as a powerful tool in CRC prevention and ***,we provide an overview of the relationship between gut microbiome and CRC,and explore relevant mechanisms of colorectal *** next highlight the potential of bacterial species as clinical biomarkers,as well as their roles in therapeutic *** limiting the clinical translation of gut microbiome and strategies for resolving current challenges are further discussed.

关键词： Gut microbiome Colorectal cancer Diagnostic biomarker Immunotherapy Chemotherapy

Time-history performance optimization of flapping wing motion using a deep learning based prediction model

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Chinese Journal of Aeronautics 2024年第5期37卷 317-331页

作者： Tianqi WANG liu liU Jun li lifang ZENG School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China Huanjiang Laboratory Zhuji 311800China

Flapping wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and *** wing motion is a very important factor that affects the performance of the aircraft,and previous works have always focused on the time-averaged performance ***,the time-history performance is equally important in the design of motion mechanism and flight control *** this paper,a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented,which is designed in order to obtain the optimal two-dimensional flapping wing ***,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics *** aerodynamic surrogate model for flapping wing is obtained after the convergence of *** surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and ***,the optimization framework is used to optimize the flapping wing motion in two specific cases,in which the optimized propulsive efficiencies have been improved by over 40%compared with the ***,a dimensionless parameter C_(variation)is proposed to describe the variation of the time-history characteristics,and it is found that C_(variation)of lift varies significantly even under close time-averaged *** the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried *** final optimal flapping wing motion balances good time-averaged and time-history performance.

关键词： FWMAV Flapping wing motion Deep learning Unsteady aerodynamic performance Optimization Time-history curve

Data-driven active vibration control for helicopter with trailing-edge flaps using adaptive dynamic programming

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Chinese Journal of Aeronautics 2024年第6期37卷 151-166页

作者： Yu CHEN Qun ZONG Xiuyun ZHANG Jinna li School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China School of Information and Control Engineering Liaoning Petrochemical UniversityFushun 113001China

The helicopter Trailing-Edge Flaps(TEFs)technology is one of the recent hot topics in morphing wing *** employing controlled deflection,TEFs can effectively reduce the vibration level of ***,designing specific vibration reduction control methods for the helicopters equipped with trailing-edge flaps is of significant practical *** paper studies the optimal control problem for helicopter-vibration systems with TEFs under the framework of adaptive dynamic programming combined with Reinforcement Learning(RL).Time-delay and disturbances,caused by complexity of helicopter dynamics,inevitably deteriorate the control performance of vibration *** solve this problem,a zero-sum game formulation with a linear quadratic form for reducing vibration of helicopter systems is presented with a virtual *** this context,an off-policy reinforcement learning algorithm is developed to determine the optimal control *** algorithm utilizes only vertical vibration load data to achieve a policy that reduces vibration,attains Nash equilibrium,and addresses disturbances while compensating for time-delay without knowledge of the dynamics of the helicopter *** effectiveness of the proposed method is demonstrated in a virtual platform.

关键词： Active control Adaptive dynamic program-ming Helicopter rotor Vibration control Zero-sum game

Hydraulic fracturing behaviors of shale under coupled stress and temperature conditions simulating different burial depths

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International Journal of Mining Science and Technology 2024年第6期34卷 783-797页

作者： Qin Zhou Zheming Zhu Wei liu Huijun Lu Zidong Fan Xiaofang Nie Cunbao li Jun Wang li Ren MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Downhole Operating Company CNPC Chuanqing Drilling and Exploration Engineering Co.Ltd.Shenzhen 518060China School of Architecture and Civil Engineering Xihua UniversityChengdu 610065China Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Shenzhen UniversityShenzhen 518060China

Fracture propagation in shale under in situ conditions is a critical but poorly understood mechanical process in hydraulic fracturing for deep shale gas reservoirs. To address this, hydraulic fracturing experiments were conducted on hollow double-wing crack specimens of the Longmaxi shale under conditions simulating the ground surface(confining pressure σ_(cp)=0, room temperature(Tr)) and at depths of 1600 m(σ_(cp)=40 MPa, Ti=70 ℃) and 3300 m(σ_(cp)=80 MPa, high temperature Ti=110 ℃) in the study *** in situ stress was found to significantly increase fracture toughness through constrained microcracking and particle frictional bridging mechanisms. Increasing the temperature enhances rather than weakens the fracture resistance because it increases the grain debonding length, which dissipates more plastic energy and enlarges grains to close microdefects and generate compressive stress to inhibit microcracking. Interestingly, the fracture toughness anisotropy in the shale was found to be nearly constant across burial depths, despite reported variations with increasing confining pressure. Heated water was not found to be as important as the in situ environment in influencing shale fracture. These findings emphasize the need to test the fracture toughness of deep shales under coupled in situ stress and temperature conditions rather than focusing on either in situ stress or temperature alone.

关键词： Hydraulic fracturing Fracture toughness Shale Anisotropy Deep rock mechanics

Inverse aerodynamic design for distributed propulsion wing with expected circulation distribution

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CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 206-223页

作者： Sun, Pengbo Zhou, Zhou li, Xu Wang, Kelei Northwestern Polytech Univ Sch Aeronaut Xian 710072 Peoples R China

Distributed Propulsion wing (DPW) technology offers significant advantages in terms of flight energy savings, but the strong aerodynamic coupling between the propulsive internal flow and aerodynamic external flow brings significant design challenges. As the primary DPW profile design is of great significance, this paper proposes a hybrid method to solve the inverse problem mainly based on the formula relationship between the required aerodynamic loads and the profile shape, which is more direct and instructive compared with traditional parametric iterative methods. The aerodynamic characteristics are described by the circulation distribution in the Fourier series form, then the mean camber line of the profile is solved through the re-derived airfoil theory considering disk's influence. Further CFD correction methods are also proposed. To validate the effectiveness and feasibility of the proposed hybrid inverse method, several DPW profile design tests are then conducted. Finally, the relationship between 2D and realistic 3D unit shape is also researched. The results show that the proposed inverse design method has great accuracy and convergence speed in the design tests, and shows good robustness against changes of the design parameters. The 2D profile shape and the actual 3D shape of DPW unit can establish an aerodynamicpropulsion equivalent relationship based on the same internal mass fluxes. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Inverse problem Aerodynamic load Fourier series Flux FLOW SIMULATION SHAPE DESIGN HYBRID OPTIMIZATION