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

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 maneuverability.Flapping 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 optimization.However,the time-history performance is equally important in the design of motion mechanism and flight control system.In 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 motion.Firstly,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics method.The aerodynamic surrogate model for flapping wing is obtained after the convergence of training.The surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and moment.Secondly,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 baselines.Thirdly,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 performances.Considering the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried out.The 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

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Thioacetamide Additive Homogenizing Zn Deposition Revealed by In Situ Digital Holography for Advanced Zn Ion Batteries

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Nano-Micro Letters 2024年第6期16卷 261-275页

作者： Kaixin Ren Min Li Qinghong Wang Baohua liu Chuang Sun Boyu Yuan Chao Lai lifang Jiao Chao Wang School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou 221116JiangsuPeople’s Republic of China Jiangsu Key Laboratory of Advanced Laser Materials and Devices School ofPhysics and Electronic EngineeringJiangsu Normal UniversityXuzhou 221116JiangsuPeople’s Republic of China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai University300071 TianjinPeople’s Republic of China

Zinc ion batteries are considered as potential energy storage devices due to their advantages of low-cost,high-safety,and high theoretical capacity.However,dendrite growth and chemical corrosion occurring on Zn anode limit their commercialization.These problems can be tackled through the optimization of the electrolyte.However,the screening of electrolyte additives using normal electrochemical methods is time-consuming and labor-intensive.Herein,a fast and simple method based on the digital holography is developed.It can realize the in situ monitoring of electrode/electrolyte interface and provide direct information concerning ion concentration evolution of the diffusion layer.It is effective and time-saving in estimating the homogeneity of the deposition layer and predicting the tendency of dendrite growth,thus able to value the applicability of electrolyte additives.The feasibility of this method is further validated by the forecast and evaluation of thioacetamide additive.Based on systematic characterization,it is proved that the introduction of thioacetamide can not only regulate the interficial ion flux to induce dendrite-free Zn deposition,but also construct adsorption molecule layers to inhibit side reactions of Zn anode.Being easy to operate,capable of in situ observation,and able to endure harsh conditions,digital holography method will be a promising approach for the interfacial investigation of other battery systems.

关键词： Digital holographic microscopy In situ observation Electrode/electrolyte interface Zn dendrites Screening electrolyte additives

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Rh(Ⅱ)-catalyzed intermolecular carboamination of pyridines via double Csp^(2)-H bond activations

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Science China Chemistry 2024年第1期67卷 374-382页

作者： Zhongfeng Luo Jingxing Jiang lifang Zou Xiaoyu Zhou Junshan liu Zhuofeng Ke Fengjuan Chen Huanfeng Jiang Wei Zeng Key Laboratory of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510641China School of Materials Science and Engineering PCFM LabSun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Chinese Medicine Pharmaceutics School of Traditional Chinese MedicineSouthern Medical UniversityGuangzhou 510515China

We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp^(2)-H functionalizations.A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized azaindoles.Mechanistic studies including DFT calculations unveil that relay carbenoidelectrophilic addition to pyridines and the sequential pyridyl Csp^(2)-H amination are involved in this transformation.The postsynthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.

关键词： Rh-catalysis azaindoles pyridyl Csp^(2)-H bond carboamination coupling-cyclization

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Brain circuits for retching-like behavior

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National Science Review 2024年第1期11卷 145-160页

作者： lifang Huo Zhimin Ye Meiling liu Ziqing He Meizhu Huang Dapeng Li Qian Wu Qian Wang Xiaoqun Wang Peng Cao Ji Dong Congping Shang School of Basic Medical Sciences Guangzhou National Laboratory The Fifth Afflliated Hospital Guangzhou Medical University Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory) Department of Neurobiology School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and Repair Advanced Innovation Center for Human Brain Protection Capital Medical University State Key Laboratory of Cognitive Neuroscience and Learning IDG/McGovern Institute for Brain Research Beijing Normal University Changping Life Science Laboratory National Institute of Biological Sciences

Nausea and vomiting are important defensive responses to cope with pathogens and toxins that invade the body. The nucleus of the solitary tract(NTS) is important for initiating these responses. However, the molecular heterogeneities and cellular diversities of the NTS occlude a better understanding of these defensive responses. Here, we constructed the single-nucleus transcriptomic atlas of NTS cells and found multiple populations of NTS neurons that may be involved in these defensive responses. Among these, we identified Calbindin1-positive(Calb1+) NTS neurons that are molecularly distinct from Tac1+neurons.These Calb1+neurons are critical for nausea and retching induced by cereulide; an emetic toxin secreted by Bacillus Cereus. Strikingly, we found that cereulide can directly modulate vagal sensory neurons that innervate Calb1+NTS neurons, a novel mechanism distinct from that for nausea and retching induced by Staphylococcal enterotoxin A. Together, our transcriptomic atlas of NTS neurons and the functional analyses revealed the neural mechanism for cereulide-induced retching-like behavior. These results demonstrate the molecular and cellular complexities in the brain that underlie defensive responses to the diversities of pathogens and toxins.

关键词： vomiting nausea nucleus of the solitary tract Calbindin1 neural circuits

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Research on a Composite Biomass Insulation Material with Geopolymers as Binders and Forestry Waste as Fillers

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Journal of Thermal Science 2022年第2期31卷 590-605页

作者： LI Hongqiang ZOU Si liu Tiantian WANG Shuang ZOU Jun ZHANG Xiaofeng liu lifang BAI Chengying ZHANG Guoqiang College of Civil Engineering Hunan UniversityChangsha 410082China National Center for International Research Collaboration in Building Safety and Environment(NCIRCBSE) Hunan UniversityChangsha 410082China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan UniversityChangsha 410082China State Key Laboratory of Plant Physiology and Biochemistry China Agricultural UniversityBeijing 100193China College of Energy and Power Engineering Changsha University of Science and TechnologyChangsha 410114China College of Civil Engineering Hunan University of Science and TechnologyXiangtan 411201China Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China

A composite biomass insulation material,which uses geopolymers as adhesives and forestry waste as fillers,was proposed and experimentally tested.The orthogonal experimental method was adopted to analyze the optimum theoretical oxide molar ratios and the mass ratio of mixing water to binder(m_(w2)/m__(B))for preparing geopolymers.The influences of curing regimes(including one-stage and two-stage curing methods)and m_(w2)/m_(B) ratios of the insulation materials on mechanical,thermal,and hydraulic performances were also studied by experiment.The results indicated that the optimum combination scheme of preparing geopolymers was molar ratio x_(SiO_(2))/x_(Na_(2)O)=3.3,x_(SiO_(2))/x_(Al_(2)O_(3))=3.2 and m_(w2)/m_(B)=0.5 with the highest mechanical strength of 34.21 MPa.Besides,the best curing conditions of the composite material were the curing temperatures of 85°C and 70°C under the two-stage curing regime,which could achieve the low heat conductivity of 0.123 and 0.125 W/(m·K),and the high mechanical strength of 1.70 MPa and 1.71 MPa,respectively.The optimum m_(w2)/m_(B)ratios of the biomass material were 0.5 to 0.55 with heat conductivity of 0.114 to 0.125 W/(m·K).This novel composite insulation material has satisfying physical performances,which is helpful for achieving building energy conservation.

关键词： sawdust forestry waste energy conservation prefabricated buildings composite biomass insulation materials

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Fault diagnosis based on dial-test data in datacenter networks

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Journal of Systems Engineering and Electronics 2019年第5期30卷 1035-1043页

作者： QI Xiaogang WANG Bingchun liu lifang School of Mathematics and Statistics Xidian UniversityXi’an 710071China School of Computer Science and Technology Xidian UniversityXi’an 710071China Xidian-Ningbo Information Technology Institute Ningbo 315200China

The fast growth of datacenter networks,in terms of both scale and structural complexity,has led to an increase of network failure and hence brings new challenges to network management systems.As network failure such as node failure is inevitable,how to find fault detection and diagnosis approaches that can effectively restore the network communication function and reduce the loss due to failure has been recognized as an important research problem in both academia and industry.This research focuses on exploring issues of node failure,and presents a proactive fault diagnosis algorithm called heuristic breadth-first detection(HBFD),through dynamically searching the spanning tree,analyzing the dial-test data and choosing a reasonable threshold to locate fault nodes.Both theoretical analysis and simulation results demonstrate that HBFD can diagnose node failures effectively,and take a smaller number of detection and a lower false rate without sacrificing accuracy.

关键词： datacenter network node failure proactive fault diagnosis

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SEM-Based Method for Performance Evaluation of Wired LANs

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第3期35卷 403-412页

作者： Qi Xiaogang Xu Chunxia liu lifang School of Mathematics and Statistics Xidian University School of Computer Science and Technology Xidian University

For wired local area networks(LANs),their effectiveness and invulnerability are very critical.It is extraordinarily significant to evaluate the network performance effectively in the design of a reasonable network topology and the performance improvement of the networks.However,there are many factors affecting the performance of the networks,and the relation among them is also complicated.How to evaluate the performance of the wired LANs more accurately has been a heavy challenge in the network research.In order to solve the problem,this paper presents a performance evaluation method that evaluates the effectiveness and invulnerability of the wired LANs.Compared to traditional statistical methods,it has the distinct advantage of being able to handle several dependent variables simultaneously and tolerates the measurement errors among these independent variables and dependent variables.Finally,the rationality and validity of this method are verified by the extensive experimental simulation.

关键词： wired local area networks(LANs) structural equation model(SEM) node contribution performance prediction network topology

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Research on performance of complex networks based on principal component analysis

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The Journal of China Universities of Posts and Telecommunications 2019年第1期26卷 40-48页

作者： Xu Chunxia Qi Xiaogang liu lifang School of Mathematics and Statistics Xidian University School of Computer Science and Technology Xidian University

For complex networks, their effectiveness and invulnerability are extremely important. With the development of complex networks, how to evaluate the effectiveness and invulnerability of these networks becomes an important research topic. The relationship among many influencing factors is very complicated, so it is essential to confirm the weighting coefficient of these influencing factors. Principal component analysis(PCA) is proposed to evaluate the performance of complex networks. It can improve one-sidedness of the single evaluation index and select different evaluation models according to different complex networks, which make the evaluation result more accurate. Performance of complex networks can be predicted according to comprehensive evaluation model. To verify the rationality and validity of this method, several small-world networks with different probability values and scale-free network are chosen to evaluate the network performance. Finally, simulation results show that PCA can be applied to performance evaluation of complex networks.

关键词： complex networks network topology principal component analysis performance prediction

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A 1G-cell floating-gate NOR flash memory in 65 nm technology with 100 ns random access time

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Science China(Information Sciences) 2015年第4期58卷 158-165页

作者： liu lifang WU Dong liu XueMei HUO ZongLiang liu Ming PAN LiYang Institute of Microelectronics University of Tsinghua Tsinghua National Laboratory for Information Science and Technology Laboratory of Nano-Fabrication and Novel Devices Integrated Technology Institute of MicroelectronicsChinese Academy of Sciences

A 1G-cell NOR flash memory chip has been designed and fabricated successfully with 65 nm technology. To compromise the array efficiency and chip speed, the paper establishes an array model including parasitics of the whole array, and optimizes the sector structure as 512 wordlines(WLs) and 4096 bitlines(BLs).Furthermore, by adding other models of long and thin metal lines, we have analyzed the speed of critical circuit nodes. As a result, the agreement of WL delay between simulation and measurement verifies the accuracy of the array model and lines models. The test results indicate that the chip achieves random access time of 100 ns and page read time of 25 ns under 3.3 V voltage supply.

关键词： NOR flash memory giga-level 65 nm technology array efficiency high speed

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3,3-二甲基-1-丁醇抑制肠道三甲胺生成可缓解溃疡性结肠炎及继发性肝损伤

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中国药科大学学报 2024年第2期55卷 246-256页

作者：王鑫楠刘丽芳中国药科大学中药学院生药学系南京211198 江苏省疾病预防控制中心南京210009

溃疡性结肠炎(ulcerative colitis,UC)是多种因素导致的肠道慢性疾病,严重的肠炎会引起肝脏损伤。肠道炎症诱发菌群紊乱,导致肠道中过多的胆碱转化为三甲胺;宿主中过低的胆碱生物利用度是造成肝脏损伤的重要原因。3,3-二甲基-1-丁醇(3,3... 详细信息

溃疡性结肠炎(ulcerative colitis,UC)是多种因素导致的肠道慢性疾病,严重的肠炎会引起肝脏损伤。肠道炎症诱发菌群紊乱,导致肠道中过多的胆碱转化为三甲胺;宿主中过低的胆碱生物利用度是造成肝脏损伤的重要原因。3,3-二甲基-1-丁醇(3,3-dimethyl-1-butanol,DMB)作为胆碱的结构类似物,可有效抑制肠道中胆碱转化为三甲胺,本研究旨在探究DMB能否通过减少肠道内的胆碱的不良转化来改善UC小鼠结肠炎症及继发性肝损伤。采用葡聚糖硫酸钠诱导的结肠炎模型,造模结束后,评估结肠及肝组织病理,检测肝功能相关生化指标,使用超高效液相色谱串联质谱法检测UC所致的体内胆碱代谢变化。结果表明,DMB能够减轻UC小鼠体重下降指数,缓解结肠炎症,减少肝脏损伤,对小鼠的血清、肠道内容物与肝脏进行胆碱相关代谢物的检测,发现DMB能够有效抑制肠道中胆碱转化为三甲胺,提高宿主的胆碱利用度,有效缓解结肠炎的恶化,从而减少由于严重的肠道病变导致的肝脏受损。

关键词：胆碱代谢结肠炎肠道菌群代谢三甲胺

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