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Fresh-Keeping Decision and Coordination of Fresh Agricultural Product Supply Chain Considering Carbon Cap-and-Trade under Different Dominance

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 30-51页

作者： Yang Yang Guanxin yao China Institute for Agricultural Equipment Industrial Development Jiangsu UniversityZhenjiang212013China Jiangsu Modern Logistics Research Base Yangzhou UniversityYangzhou225009China

In the context of low carbon,this paper discussed the impact of the carbon cap-and-trade policy on the fresh-keeping decision-making of two-echelon fresh agricultural product supply chains under different dominance,and designed cost-sharing contracts to coordinate the supply chain of fresh agricultural products dominated by suppliers and retailers *** results showed that:dominance has no effect on the fresh-keeping decision and total revenue of fresh agricultural product supply chain,but it affects the internal income distribution,and dominance does not always bring more benefits;the implementation of carbon cap-and-trade reduces the fresh-keeping decision-making of fresh agricultural products supply chain and reduces the free-rider income of followers;the role of higher carbon trading price is twofold,which not only brings about the speculation of leading enterprises,but also promotes the application of low-carbon technologies;consumers’high preference for freshness,low-cost and high-efficiency low-carbon technology are all conducive to improving the fresh-keeping efforts and benefits of the supply chain;cost-sharing contracts can coordinate the supply chain of fresh agricultural products.

关键词： Dominant power carbon cap-and-trade policy fresh agricultural product supply chain fresh-keeping decision-making

Numerical investigation of non-uniform temperature fields for proppant and fluid phases in supercritical CO_(2)fracturing

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Particuology 2024年第7期90卷 149-163页

作者： Boyu Liu Jun yao Research Center of Multiphase Flow in Porous Media China University of Petroleum(East China)Qingdao 266000China

The non-uniform temperature distribution in supercritical CO_(2)(Sc-CO_(2))fracturing influences the density,viscosity,and volume expansion or shrinkage rate of Sc-CO_(2),impacting proppant *** study presents a coupled computational fluid dynamics-discrete element method and heat transfer model to examine the effects of proppant bed shape and the heat transfers of proppant-wall,proppant-fluid,and fluid-wall on the fluid and proppant temperature *** Sc-CO_(2)volume expansion is assessed under various temperature conditions by evaluating the volume-averaged Sc-CO_(2)*** factors,including proppant size,shape,thermal conductivity,concentration,temperature difference,and injection velocity,are carefully analyzed to elucidate their *** findings elucidate the existence of four distinct zones in the fluid temperature *** zone exhibits different magnitudes of temperature change under diverse conditions and undergoes dynamic transformations with the development of the proppant *** fluid-wall heat transfer and the fluid temperatures in Zones C and D are significantly subject to the fluid injection velocity(governing the heating duration),the temperature difference between fluid and formation(impacting the magnitude of heat flux),and the proppant bed shape(controlling the effective heating area).Additionally,the proppant-wall and proppant-fluid heat transfers determine the temperatures of both the proppant bed and the fluid within Zone B,showing a strong correlation with proppant thermal conductivity,proppant size,injection velocity,and temperature *** proposed coupled model provides valuable insights into the temperature distributions and flow behaviors of temperature-dependent fracturing fluids and proppants.

关键词： CFD-DEM Heat transfer Compressible fluid CO_(2)sequestration Proppant transport

Limits of Uneven Battery Power in Modular Multilevel Converter-based Battery Energy Storage Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 686-695页

作者： yao Pan Xiaofeng Sun Wei Zhao Xin Li yao Cai Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

For modular multilevel converter-based battery energy storage systems (MMC-BESS), uneven power among batteries of SMs will be deduced by battery aging, battery fault, etc., which will degrade performance and even lead to system failure. For maintaining the balance of capacitor voltage, this paper analyzes the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analysis, an analytical method is proposed that only the dc and fundamental frequency components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability of power distribution among batteries. Meanwhile, increase of fundamental frequency component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally, simulation model and experiment prototype are built for verifying the theoretical analysis and current limits calculation method, and satisfactory results are provided.

关键词： Arm current balance of capacitor voltage current limits MMC-BESS uneven power

Preparation of TiO_(2) Nano-Flower Coating on Ti Substrates with Good Physical Sterilization Effect and Biocompatibility

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1581-1589页

作者： Ruoyu Di Yonghua Sun Runhua yao Sen Pei Xiaohong yao Ruiqiang Hang Shanxi Key Laboratory of Biomedical Metal Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan030024China College of Safety and Emergency Management Engineering Taiyuan University of TechnologyTaiyuan030024China

We report a facile solution method to form titanium oxide(TiO_(2))nano-flower structure on the titanium(Ti)substrates for realizing good physical sterilization and *** first prepare TiO_(2) nanotubes(NT)with a diameter of about 80-100 nm and a length of about 5μm on Ti substrates by anodization,which is utilized as ***,we employ immersion treatment in different concentrations of phosphoric acid solution at 75℃ for 5 h to realize the transformation from TiO_(2) NT to TiO_(2) nano-flower *** addition,we studied the effects of phosphoric acid concentration(1 wt%,2.5 wt%,5 wt% and 10 wt%)on the TiO_(2) nano-flower structure,and the antibacterial properties and biocompatibility of the TiO_(2) nano-flower *** results show that TiO_(2) nano-flower structure become larger and thicker with the increase in the phosphoric acid concentration,and the thickness of the coating can reach 6.88μ***,the TiO_(2) nano-flower structure shows good physical sterilization effect,especially for the TiO_(2) nano-flower structure formed in 10 wt%H^(3)PO_(4. solution,the antibacterial rate can reach 95%.In addition,the TiO_(2) nano-flower structure have no toxicity to the osteoblasts and support cell growth.

关键词： Anodization Biocompatibility Physical sterilization TiO_(2)nano-flower

A deformation criterion of pressurized non-circular cross-section cabin and its effects on cruise performance of BWB civil aircraft

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Chinese Journal of Aeronautics 2024年第6期37卷 78-88页

作者： Siyi GUO Zhenli CHEN Xuanyu yao School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Aero Engine Academy of China Beijing 101304China

Blended-Wing-Body(BWB)aircraft is promoted as one of the most possible layouts to achieve more sustainable civil *** to the non-circular cross-section of the center-body,a bulge deformation forms over the upper surface of the body under the coupled loads of the internal pressurization of the cabin and the aerodynamic bending moments of the wing,which reduces the lift-to-drag ratio of BWB *** a limited deformation,the relationship between the aerodynamic performance and the structural weight needs to be *** this work,the effects of stiffness constraints on the center-body deformation,structural weight of the airframe and aerodynamic performance were investigated by using an analytical model of the Pultruded Rod Stitched Efficient Unitized Structure(PRSEUS)for the airframe and the computational fluid dynamics method,*** results show that as the stiffness constraint increases,the spacings between the rod stringers and the frame stiffeners decrease,and the structural weight increases inversely.A 5.2% reduction of the lift-to-drag ratio is encountered at cruise for a medium deformation design of 4..8 mm/m.A higher aerodynamic penalty is suffered when the stiffness constraint is further *** final deformation criterion is different when the weight vector of the aerodynamic performance and structural weight is different.

关键词： Blended-Wing-Body(BWB) Deformation PultrudedRod Stitched Effi-cient Unitized Structure(PRSEUS) Cabin structure Stiffness constraint

Active Fault Tolerant Nonsingular Terminal Sliding Mode Control for Electromechanical System Based on Support Vector Machine

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 189-203页

作者： Jian Hu Zhengyin Yang Jianyong yao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Effective fault diagnosis and fault-tolerant control method for aeronautics electromechanical actuator is concerned in this *** borrowing the advantages of model-driven and data-driven methods,a fault tolerant nonsingular terminal sliding mode control method based on support vector machine(SVM)is proposed.A SVM is designed to estimate the fault by off-line learning from small sample data with solving convex quadratic programming method and is introduced into a high-gain observer,so as to improve the state estimation and fault detection accuracy when the fault *** state estimation value of the observer is used for state reconfiguration.A novel nonsingular terminal sliding mode surface is designed,and Lyapunov theorem is used to derive a parameter adaptation law and a control *** is guaranteed that the proposed controller can achieve asymptotical stability which is superior to many advanced fault-tolerant *** addition,the parameter estimation also can help to diagnose the system faults because the faults can be reflected by the parameters *** comparative simulation and experimental results illustrate the effectiveness and advancement of the proposed controller compared with several other main-stream controllers.

关键词： Aeronautics electromechanical actuator Fault tolerant control Support vector machine State observer Parametric uncertainty

Multi-Robot Cooperative Localization:Time-Varying Unobservable Subspace Analysis and Consistent Algorithm Design

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Journal of Systems Science & Complexity 2024年第5期37卷 1937-1955页

作者： HAO Ning HE Fenghua yao Yu School of Astronautics Harbin Institute of TechnologyHarbin 150000China

This paper investigates the problem of cooperative localization(CL)for a multi-robot system(MRS)under dynamic measurement topology,which involves a group of robots collectively estimating their poses with respect to a common reference frame using ego-motion measurements and robot-to-robot relative *** authors provide a theoretical analysis of the time-varying unobservable subspace and propose a consistent cooperative localization ***,the authors introduce the relative measurement graph(RMG)to represent the relative pose measurements obtained by the MRS at each ***,the authors derive the local observability matrix over a time *** equivalent relationship is established between the local observability matrix and the spectral matrices of the ***,the authors present a method for constructing the unobservable subspace based on the RMG under different topology *** on this analysis,the authors design a consistent cooperative localization algorithm that satisfies the constraints of the time-varying unobservable *** analytical optimal solution is derived for the constrained optimization *** Carlo numerical simulations are conducted to demonstrate the consistency and accuracy of the proposed method.

关键词： Consistency cooperative localization multi-robot system null space relative measurement graph time-varying unobservable subspace

Initial costates derived by near-optimal reference sequence and least-squares method

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Chinese Journal of Aeronautics 2024年第5期37卷 377-391页

作者： Shaozhao LU yao ZHANG Quan HU School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

In this paper,we present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion with continuous low *** proposed solver consists of two primary components:training a Multilayer Perceptron(MLP)for generating reference sequence and Time of Flight(TOF)to the target,and deriving a system of linear algebraic equations for obtaining the initial *** overcome the challenge of generating training samples for the MLP,the backward generation method is proposed to obtain five different training *** training database and sample form are determined by analyzing the input and output correlation using the Pearson correlation *** best-performing MLP is obtained by analyzing the training results with various hyper-parameter combinations.A reference sequence starting from the initial states is obtained by integrating forward with the near-optimal control vector from the output of ***,a system of linear algebraic equations for estimating the initial costates is derived using the reference sequence and the necessary conditions for *** results demonstrate that the proposed initial costates solver improves the convergence ratio and reduce the function calls of the shooting ***,Monte-Carlo simulation illustrates that the initial costates solver is applicable to different initial velocities,demonstrating excellent generalization ability.

关键词： Relative motion Expanding training database Multilayer perceptron Initial costates Least-squares method

Lesson Learned from COVID-19 Retrospective Study: An Entropy-Based Clinical-Interpretable Scorecard for Mortality Risk Control at ICU Admission

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Tsinghua Science and Technology 2024年第1期29卷 34-45页

作者： Chong yao Chonghui Huangqi Anpeng Huang Laboratory of Network Information Security Beihang UniversityBeijing 100191China Andrew and Erna Viterbi School of Engineering University of Southern CaliforniaLos AnglesCA 90089USA Beijing Goodwill Information and Technology Co. Ltd.and Mobile Health LaboratoryPeking UniversityBeijing 100871China

With severe acute respiratory syndrome coronavirus 2 spreading globally and causing 2019 coronavirus disease(COVID-19),a challenge that we unprepared for was about how to optimally plan and distribute limited top-medical resources for patients in need of urgent *** address this challenge,physicians desperately needed a scientific tool to methodically differentiate between cases with varying *** this study,the unique data of COVID-19 intensive care unit(ICU)patients provided by the national medical team in Wuhan were classified into discrete and continuous variable *** continuous data were discretized using an entropy-based method and transformed into serial information margins,in which each information margin is related to a specific symptom or clinical ***,all these native and processed discrete data were used to configure a readable scorecard through logistic regression,which is the desired scientific tool aforementioned.A total of 322 ICU patients(age:[median:64.interquartile range:54.75],males:178[55.28%],and death:72[22.36%])were included in the *** of mortality in COVID-19 patients can be evaluated using a scorecard model(calibration slope:1.34.,Brier:0.04.,Dxy=0.972,and population stability index=0.071),with desired model performances(accuracy=0.94.,area under curve=0.99,sensitivity=1,and specificity=0.939).This new model can interpret clinical meanings from complex data,and compare it with existing machine learning methods through a black-box *** new data-information model answers a critical question of how a computing algorithm produces clinically meaningful results that will help physicians logically allocate medical resources for COVID-19 ***,this tool has limitations,giving that this research is a retrospective ***,this tool will be tested further and optimized for adaptation to similar clinical cases in the future.

关键词： COVID-19 scorecard clinical-interpretable machine learning ICU admission control