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Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： dong wang jing YANG Kai XIONG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

A benchmark-based method for evaluating hyperparameter optimization techniques of neural networks for surface water quality prediction

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 13-27页

作者： Xuan wang Yan dong jing Yang Zhipeng Liu Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Green Building in West China Xi’an University of Architecture and TechnologyXi’an710055China

Neural networks(NNs)have been used extensively in surface water prediction tasks due to computing algorithm improvements and data *** essential step in developing an NN is the hyperparameter *** practice,it is common to manually determine hyperparameters in the studies of NNs in water resources *** may result in considerable randomness and require significant computation time;therefore,hyperparameter optimization(HPO)is *** study adopted five representatives of the HPO techniques in the surface water quality prediction tasks,including the grid sampling(GS),random search(RS),genetic algorithm(GA),Bayesian optimization(BO)based on the Gaussian process(GP),and the tree Parzen estimator(TPE).For the evaluation of these techniques,this study proposed a method:first,the optimal hyperparameter value sets achieved by GS were regarded as the benchmark;then,the other HPO techniques were evaluated and compared with the benchmark in convergence,optimization orientation,and consistency of the optimized *** results indicated that the TPE-based BO algorithm was recommended because it yielded stable convergence,reasonable optimization orientation,and the highest consistency rates with the benchmark *** optimization consistency rates via TPE for the hyperparameters hidden layers,hidden dimension,learning rate,and batch size were 86.7%,73.3%,73.3%,and 80.0%,*** the evaluation of HPO techniques directly based on the prediction performance of the optimized NN in a single HPO test,the proposed benchmark-based HPO evaluation approach is feasible and robust.

关键词： Neural networks Hyperparameter optimization Surface water quality prediction Bayes optimization Genetic algorithm

Prediction and interpretation of photocatalytic NO removal on g-C_(3)N_(4)-based catalysts using machine learning

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Chinese Chemical Letters 2024年第2期35卷 477-483页

作者： jing Li Xinyan Liu Hong wang Yanjuan Sun Fan dong School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu 611731China Research Center for Carbon-Neutral Environmental & Energy Technology Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu 611731China

Predictive modeling of photocatalytic NO removal is highly desirable for efficient air pollution ***,great challenges remain in precisely predicting photocatalytic performance and understanding interactions of diverse features in the catalytic ***,a dataset of g-C_(3) N_(4)-based catalysts with 255 data points was collected from peer-reviewed publications and machine learning(ML)model was proposed to predict the NO removal *** result shows that the Gradient Boosting Decision Tree(GBDT)demonstrated the greatest prediction accuracy with R 2 of 0.999 and 0.907 on the training and test data,*** SHAP value and feature importance analysis revealed that the empirical categories for NO removal rate,in the order of importance,were catalyst characteristics>reaction process>preparation ***,the partial dependence plots broke the ML black box to further quantify the marginal contributions of the input features(e.g.,doping ratio,flow rate,and pore volume)to the model output *** ML approach presents a pure data-driven,interpretable framework,which provides new insights into the influence of catalyst characteristics,reaction process,and preparation conditions on NO removal.

关键词： Machine learning g-C_(3)N_(4)-based catalysts NO removal Interpretability Catalytic informatics

Animal models of eosinophilic esophagitis,review and perspectives

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Animal Models and Experimental Medicine 2024年第2期7卷 127-135页

作者： dong Li Yujia Wei jing wang Bo wang Department of Dermatology Huazhong University of Science and Technology Tongji Medical College Tongji HospitalWuhanChina Health Management Center Huazhong University of Science and Technology Tongji Medical College Tongji HospitalWuhanChina Department of Gastroenterology Huazhong University of Science and Technology Tongji Medical College Tongji HospitalWuhanChina

Eosinophilic oesophagitis(EoE)is an allergen/immune-mediated chronic esophageal disease characterized by esophageal mucosal eosinophilic infiltration and esophageal *** the disease was originally attributed to a delayed allergic reaction to allergens and a Th2-type immune response,the exact pathogenesis is complex,and the efficacy of existing treatments is ***,the study of the pathophysiological process of EOE has received increasing *** models have been used extensively to study the molecular mechanism of EOE pathogenesis and also provide a preclinical platform for human clinical intervention studies of novel therapeutic *** maximize the use of existing animal models of EOE,it is important to understand the advantages or limitations of each modeling *** paper systematically describes the selection of experimental animals,types of allergens,and methods of sensitization and excitation during the preparation of animal models of *** also discusses the utility and shortcomings of each model with the aim of providing the latest perspectives on EoE models and leading to better choices of animal models.

关键词： anaphylaxis disease models animal eosinophilic esophagitis methods

Macrocyclic peptides:up-and-coming weapons to combat antimicrobial resistance

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Signal Transduction and Targeted Therapy 2024年第5期9卷 1786-1787页

作者： Wen-jing wang Xiang-Min dong Guo-Bo L Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengduSichuanChina Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education Department of Medicinal ChemistryWest China School of PharmacySichuan UniversityChengduSichuanChina

Recently,two companion papers published in Nature reported a first-in-class tethered macrocyclic peptide antibiotic targeting carbapenem-resistant ***(CRAB)and unveiled their unique antibacterial mechanism,which invol... 详细信息

关键词： outer macrocyclic Macrocyclic

Effect of long reaction distance on gas composition from organic-rich shale pyrolysis under high-temperature steam environment

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International Journal of Coal Science & Technology 2024年第3期11卷 102-119页

作者： Lei wang Rui Zhang Guoying wang jing Zhao dong Yang Zhiqin Kang Yangsheng Zhao Key Laboratory of In-Situ Property Improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China The In-Situ Steam Injection Branch of State Center for Research and Development of Organic-Rich Shale Exploitation Taiyuan University of TechnologyTaiyuan030024China College of Mining Engineering Taiyuan University of TechnologyTaiyuan030024China School of Energy Science and Engineering Henan Polytechnic UniversityJiaozuo454002China

When high-temperature steam is used as a medium to pyrolyze organic-rich shale,water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis,thus affecting the generation law and release characteristics of gas *** this study,based on a long-distance reaction system of organic-rich shale pyrolysis via steam injection,the effects of steam temperature and reaction distance on gas product composition are analyzed in depth and compared with other pyrolysis *** advantages of organic-rich shale pyrolysis via steam injection are then *** volume concentration of hydrogen in the gas product obtained via the steam injection pyrolysis of organic-rich shale is the highest,which is more than 60%.The hydrogen content increases as the reaction distance is extended;however,the rate of increase changes *** the reaction distance from 800 to 4000 mm increases the hydrogen content from 34.91%to 69.68%and from 63.13%to 78.61%when the steam temperature is 500°C and 555°C,***,the higher the heat injection temperature,the smaller the reaction distance required to form a high concentration hydrogen pyrolysis environment(hydrogen concentration>60%).When the steam pyrolysis temperature is increased from 500°C to 555°C,the reaction distance required to form a high concentration of hydrogen is reduced from 3800 to 800 *** with the direct retorting process,the volume concentration of hydrogen obtained from high-temperature steam pyrolysis of organic-rich shale is 8.82 and 10.72 times that of the commonly used Fushun and Kivite furnaces,*** pyrolysis of organic-rich shale via steam injection is a pyrolysis process in a hydrogen-rich environment.

关键词： Steam temperature Pyrolysis gas Hydrogen-rich Reaction distance Direct retorting

Characteristics and stability of oxide+carbonitride in H13 steel at 1250℃

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Journal of Iron and Steel Research(International) 2024年第1期31卷 134-142页

作者： Xiao-lin Sun Han-jie Guo jing Guo Fei wang dong Xu Gao-yang Song Shuai wang School of Materials Science and Engineering Hebei University of EngineeringHandan056038HebeiChina School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China High Temperature Materials Research Institute Central Iron and Steel Research Institute Co.Ltd.Beijing100081China Technology Innovation Center for High Quality Cold Heading Steel of Hebei Province Hebei University of EngineeringHandan056038HebeiChina

The morphology,size,quantity,and composition of complex oxide+carbonitride in H13 steel held at 1250℃for 5,10,and 15 h were *** results show that the ratio and number of complex carbonitrides with cores in H13 steel are gradually increased when holding at 1250℃compared with those in the original H13 steel,and the core size *** are one or more oxide cores in(Ti_(x),V_(1-x))(Cy,N_(1-y)),including xCaO·zAl_(2)O_(3),xCaO·yMgO·zAl_(2)O_(3),and CaO after holding at 1250℃,in addition to MgO·Al_(2)O_(3)and Al_(2)O_(3)in the original *** equilibrium temperature for(Ti_(x),V_(1-x))(Cy,N_(1-y))precipitation at the solidification front and decomposition in the solid state was theoretically analyzed,which was affected by the x value and the product of Ti and N contents in H13 ***,the composition of(Ti_(x),V_(1-x))(Cy,N_(1-y))is influenced by the oxide *** is convinced that(Ti_(x),V_(1-x))(Cy,N_(1-y))with oxide cores has a higher stability,especially for oxides with a high Al_(2)O_(3)*** treatment at high temperature facilitates a more reasonable analysis of oxide+carbonitride,and the generation mechanism of oxide+carbonitride was discussed.

关键词： Complex carbonitride Decomposition Oxide core Characteristic Stability

Crosslinked solubilizer enables nitrate-enriched carbonate polymer electrolytes for stable,high-voltage lithium metal batteries

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Science Bulletin 2024年第2期69卷 209-217页

作者： Chuyang jing Kuan Dai dong Liu Wenran wang Libao Chen Chunxiao Zhang Weifeng Wei State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China College of Materials and Chemical Engineering Hunan Institute of EngineeringXiangtan 411104China

High-voltage lithium metal batteries(LMBs)have been considered promising next-generation highenergy-density ***,commercial carbonate electrolytes can scarcely be employed in LMBs owing to their poor compatibility with metallic lithium.N,N-dimethylacrylamide(DMAA)-a crosslinkable solubilizer with a high Gutmann donor number-is employed to facilitate the dissolution of insoluble lithium nitrate(LiNO3)in carbonate-based electrolytes and to form gel polymer electrolytes(GPEs)through in situ *** Lit solvation structure of the GPEs is regulated using LiNO3 and DMAA,which suppresses the decomposition of LiPFe and facilitates the formation of an inorganic-rich solid electrolyte ***,the Coulombic efficiency(CE)of the LillCu cell assembled with a GPE increases to 98.5%at room temperature,and the high-voltage LillNCM622 cell achieves a capacity retention of 80.1%with a high CE of 99.5%after 400 *** bifunctional polymer electrolytes are anticipated to pave the way for next-generation high-voltage LMBs.

关键词： Crosslinked solubilizer Lithium nitrate Carbonate electrolytes Gel polymer electrolytes Lithium metal batteries

Grain size refinement of additive manufactured Ce-TZP ceramics by coupled two-step pre-sintering and HIP

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Journal of Advanced Ceramics 2024年第5期13卷 621-629页

作者： Ruoshi Zhao Hongbing Yang Xintong Liu Hezhen Li Chang-An wang jing Ma Yanhao dong State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Ceria-stabilized tetragonal zirconia polycrystal(Ce-TZP)has exceptional fracture toughness and flaw tolerance due to facile t‒m phase transformation ***,its wider-range applications are limited by its relatively low strength due to its large grain size and low transformation stress,which results in yield-like ***,we combined additive manufacturing(AM),pressureless two-step sintering,and hot isostatic pressing(HIP),and addressed the challenging grain size refinement problem in *** successfully produced dense ultrafine-grained Ce-TZP ceramics with an average grain size below 500 nm,a three-point bending strength above 800 MPa,and a single-edge-notch-beam fracture toughness in the range of 11‒12 MPa·m^(1/2).The critical roles of processing design,mixed Ce valences,and ***-stabilization of tetragonal polymorphs were *** work offers insights and strategies for the future development of stronger and tougher Ce-TZP ceramics that can compete with tetragonal yttria-stabilized zirconia in various applications,including additive manufacturing.

关键词： zirconia additive manufacturing(AM) two-step sintering hot isostatic pressing(HIP) grain size refinement