检索结果-南通市图书馆

Surrogate-assisted differential evolution using manifold learning-based sampling for highdimensional expensive constrained optimization problems

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第7期37卷 252-270页

作者： Teng long Nianhui YE Rong CHEN Renhe SHI Baoshou zhang School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle of Ministry of Education Beijing 100081China China Academy of Launch Vehicle Technology Beijing 100076China

To address the challenges of high-dimensional constrained optimization problems with expensive simulation models,a Surrogate-Assisted Differential Evolution using Manifold Learning-based Sampling(SADE-MLS)is *** SADE-MLS,differential evolution operators are executed to generate numerous high-dimensional candidate *** alleviate the curse of dimensionality,a Manifold Learning-based Sampling(MLS)mechanism is developed to explore the high-dimensional design space *** MLS,the intrinsic dimensionality of the candidate points is determined by a maximum likelihood ***,the candidate points are mapped into a low-dimensional space using the dimensionality reduction technique,which can avoid significant information loss during dimensionality ***,Kriging surrogates are constructed in the low-dimensional space to predict the responses of the mapped candidate *** candidate points with high constrained expected improvement values are selected for global ***,the local search process assisted by radial basis function and differential evolution is performed to exploit the design space *** numerical benchmarks are tested to compare SADE-MLS with other ***,SADE-MLS is successfully applied to a solid rocket motor multidisciplinary optimization problem and a re-entry vehicle aerodynamic optimization problem,with the total impulse and lift to drag ratio being increased by 32.7%and 35.5%,*** optimization results demonstrate the practicality and effectiveness of the proposed method in real engineering practices.

关键词： Surrogate-assisted differential evolution Dimensionality reduction Solid rocket motor Re-entry vehicle Expensive constrained optimization

Phase-field simulation of precipitation kinetics and creep properties of Ni-Al-Cr/Ta superalloys

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第4期67卷 1139-1150页

作者： YANG ShuaiGe zhang Zan ZHUO JiCheng long HongLi LI YongSheng National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China

The precipitation kinetics ofγ'-Ni_(3)(Al,Ta)phase and creep properties of Ni-15Al-x Ta at.%superalloys are investigated by the crystal plasticity phase-field *** results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage,while the creep lifetime is *** large external strain intensifies the creep damage and shortens the creep life of Ni-15Al-3Ta at.%*** kinetics evolution and elements distribution are revealed in the quaternary Ni-10Al-8.5Cr-xT a(x=1.5 at.%,2.0 at.%,2.5 at.%)superalloys by the multi-component phase-field *** anti-phase boundary(APB)changes the coarsening mechanism ofγ'phase,and Ta promotes the precipitation ofγ'phase with an increasing volume fraction and particle *** composition difference betweenγ'andγphases increases with the rising of Ta content,the strong partitioning of Ta toγ'phase strengthens the partitioning of Ni and Cr toγmatrix,and Ta shows a superiority than Al in the lattice site occupation of L1_(2)-Ni_(3)(Al,X)*** an importantγ'phase forming element,the optimization of Ta content is essential for improving the mechanical properties of Ni-based superalloys.

关键词： Ni-Al-Ta alloys creep properties kinetics phase-field

Astronomical forcing and sedimentary noise modeling of lake-level changes in the Middle Eocene Chezhen Sag,Bohai Bay Basin,eastern China

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2024年第2期18卷 446-459页

作者： Xuwei LUAN Jinliang zhang Na LI Tao CHEN long SUN Xuecai zhang Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China Management Center of Oil and Gas Exploration Sinopec Shengli OilfieldDongying 257000China

The accurate determination of geological age is a key to understanding the history and process of paleolake evolution and oil and gas exploration in continental lake ***,improving the accuracy of geological age has always been a difficult scientific problem.A 609-m-thick,continuous lacustrine mudstone and sandstone succession in Chezhen Sag(eastern China)provides an ideal middle Eocene sedimentary record for establishing a high-resolution stratigraphic chronology *** on spectrum analysis and sliding window spectrum analysis of the natural gamma(GR)logging data of well Che 271(C271)in Chezhen Sag,the periods of 405 kyr and 40.1 kyr were filtered by a Gaussian bandpass filter,and a“floating”astrochronological time scale(ATS)was *** total number of 405 kyr eccentricity cycles were 13.6 and 40.1 kyr obliquity cycles were 138 which recorded from the upper member 4(Es4U)to the member 3(Es3)of the Eocene Shahejie Formation,and the depositional duration was 5.53 *** Coefficient(COCO)analysis and evolutionary Correlation Coefficient(eCoCo)analysis found that the optimal sedimentary rate of different *** noise simulation revealed the history of paleolake water changes in the Middle Eocene in the Chezhen Sag,according to which four sequences are *** study shows that the lake level change of Chezhen Sag in the middle Eocene shows prominent 1.2 Myr cycles and an antiphase well-coupled relationship with obliquity ***,we propose a model to explain the relationship between the orbital cycle and lake level change in the continental lake *** the obliquity of the earth increases,the middle and high latitudes of the earth will be closer to the sun,the direct sunlight will be higher,and the meridional sunshine will increase,thus accelerating the evaporation process of lake basin *** the seasonal changes are obvious(maximum period of 1.2 Myr ultra-long obliquity),this effect is more signific

关键词： Chezhen Sag cyclostratigraphy astrochronological time scale sedimentary noise

A Survey on Blockchain-Based Federated Learning:Categorization,Application and Analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2451-2477页

作者： Yuming Tang Yitian zhang Tao Niu Zhen Li Zijian zhang Huaping Chen long zhang School of Cyberspace Science&Technology Beijing Institute of TechnologyBeijing100081China School of Computer Science&Technology Beijing Institute of TechnologyBeijing100081China Southeast Institute of Information Technology Beijing Institute of TechnologyPutian351100China Qianxin Technology Group Co. Ltd.Beijing100044China

Federated Learning(FL),as an emergent paradigm in privacy-preserving machine learning,has garnered significant interest from scholars and engineers across both academic and industrial *** its innovative approach to model training across distributed networks,FL has its vulnerabilities;the centralized server-client architecture introduces risks of single-point ***,the integrity of the global model—a cornerstone of FL—is susceptible to compromise through poisoning attacks by malicious *** attacks and the potential for privacy leakage via inference starkly undermine FL’s foundational privacy and security *** these reasons,some participants unwilling use their private data to train a model,which is a bottleneck in the development and industrialization of federated *** technology,characterized by its decentralized ledger system,offers a compelling solution to these *** inherently prevents single-point failures and,through its incentive mechanisms,motivates participants to contribute computing ***,blockchain-based FL(BCFL)emerges as a natural progression to address FL’s *** study begins with concise introductions to federated learning and blockchain technologies,followed by a formal analysis of the specific problems that FL *** discusses the challenges of combining the two technologies and presents an overview of the latest cryptographic solutions that prevent privacy leakage during communication and incentives in *** addition,this research examines the use of BCFL in various fields,such as the Internet of Things and the Internet of ***,it assesses the effectiveness of these solutions.

关键词： Federated learning blockchain privacy-preserving

Enhanced Sensing Mechanism Based on Shifting an Exceptional Point

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2024年第3期6卷 285-292页

作者： Xuan Mao Guo-Qing Qin Hao zhang Bo-Yang wang Dan long Gui-Qin Li Gui-Lu long Department of Physics State Key Laboratory of Low-Dimensional Quantum PhysicsTsinghua UniversityBeijing 100084China Beijing Institute of Radio Measurement The Second Academy of China Aerospace Science and Industry Corporation(CASIC)Beijing 100854China Purple Mountain Laboratories Nanjing 21111China Frontier Science Center for Quantum Information Beijing 100084China Beijing Academy of Quantum Information Sciences Beijing 100193China

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here, we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP nondemolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most effective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high-sensitivity sensors in different physical systems.

关键词： mechanism shifting exceptional

Flexible resource allocation optimization model considering global K-means load clustering and renewable-energy consumption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Clean Energy 2024年第5期8卷 129-143页

作者： Jie Jiao Puyu He Yuhong zhang Jiyuan zhang Zhuhan long Hanjing Liu State Grid Sichuan Electric Power Company Economic Research Institute ChengduChina

Vigorously developing flexible resources in power systems will be the key to building a new power system and realizing energy *** investment construction cost and operation cost of various flexible resources are different,and the adjustment ability is different in different ***,the optimization of complementary allocation of various resources needs to take into account the economy and adjustment ability of different *** this paper,the global K-means load clustering model is pro-posed and the 365-day net load is reduced to eight typical daily net loads by ***,a two-level optimization model of flexible resource complementary allocation considering wind power and photovoltaic consumption is *** flexible resources involved include the flexible transformation of thermal power,hydropower,pumped storage,energy storage,and demand *** upper-layer model optimizes the capacity allocation of various flexible resources with the minimum investment and construction cost as the goal and the lower layer optimizes the operating output of various units with the minimum operating cost as the *** results of the example analysis show that the flexible capacity of thermal power units has nothing to do with the abandonment rate of renewable *** the abandonment rate of renewable energy decreases,the optimal capacity of pumped storage,electrochemical energy storage,and hydropower units *** the power-abandonment rate of renewable energy is 5%,the optimal allocation capacity of thermal power flexibility transformation,pumped storage,electrochemical energy storage,hydropower unit,and adjustable load in Province A is 5313,17090,5830,72113,and 4250 MW,*** the condition that the renewable-energy abandonment rate is 0,5%,and 10%respectively,the configured capacity of pumped storage is 20000,17090,and 14847 MW,respectively.

关键词： wind power photovoltaic power K-means clustering algorithm flexible resources complementary configuration operation optimization

Review on birefringence in borates based on birefringence-active functional groups and arrangements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第7期67卷 2155-2170页

作者： Qianzhen zhang Ran An Zhihua Yang Xifa long Shilie Pan Yun Yang Research Center for Crystal Materials State Key Laboratory of Functional Materials and Devices for Special Environmental ConditionsXinjiang Key Laboratory of Functional Crystal MaterialsThe Xinjiang Technical Institute of Physics&ChemistryChinese Academy of SciencesUrumqi 830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

As a fundamental parameter of the optical crystals,birefringence plays a vital role in many optical applications,such as phase modulation,light splitting,and polarization,especially the phase matching process of the nonlinear optical *** big birefringence not only benefits to the miniaturization of related devices,but also broadens the phase-matching wavelength range of nonlinear optical *** design and synthesis of crystals with large birefringence becomes a hot research topic due to its more and more important applications in the optical modulation and laser technology ***,crystals with birefringence greater than 0.05 in the borate system are reviewed and classified according to different birefringent active groups,and the relationship between structure and properties is thoroughly *** is hoped that this review will provide a clear understanding of what kinds of building units and arrangements would have more opportunity to get adequate birefringence in borate systems and provide the statistical references to encourage the emergence of better crystal materials with large birefringence.

关键词： birefringence borate optical functional crystal structural anisotropy arrangement of functional units

Electrical control of excitonic oscillator strength and spatial distribution in a monolayer semiconductor

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8424-8430页

作者： Yanming wang Junrong zhang Tianhua Ren Meng Xia long Fang Xiangyi wang Xingwang zhang Kai zhang Junyong wang School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Nanophotonic Materials and Devices&Key Laboratory of Nanodevices and Applications i-LabSuzhou Institute of Nano-Tech and Nano-Bionics(SINANO)Chinese Academy of SciencesSuzhou 215123China Institute of Applied Physics and Materials Engineering University of MacaoTaipaMacao 999078China College of New Energy Inner Mongolia University of TechnologyHohhot 010051China

Electrical modulation of luminescence is significant to modern light-emitting *** transition metal dichalcogenides are emerging direct-bandgap luminescent materials with unique excitonic properties,and the multiple exciton complexes provide new opportunities to modulate the property of luminescence in atomically thin ***,we report an electrical control of exciton emission in the oscillator strength and spatial distribution of excitons in a monolayer *** modulation of excitonic emission intensity with a degree of modulation of~92%has been demonstrated by an electric field at room *** spatial carrier redistribution tuned by a lateral electric field results in distinct excitonic emission patterns by *** modulation approach to exciton oscillator strength and distribution provides an efficient way to investigate the exciton diffusion dynamics and to construct electrically tunable optoelectronic devices.

关键词： monolayer semiconductor exciton electrical modulation spatial distribution

Damage on intestinal barrier function and microbial detoxification of deoxynivalenol:A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第8期23卷 2507-2524页

作者： Jia Chen Xinran zhang Ziqi He Dongwei Xiong Miao long Key Laboratory of Livestock Infectious Diseases Ministry of Education/College of Animal Science and Veterinary Medicine ShenyangAgricultural UniversityShenyang 110866China

Deoxynivalenol(DON)is a mycotoxin that is produced by various species of Fusarium and is ubiquitous in food and *** low concentrations,it can cause metabolic disorders in animals and humans and,at high concentrations,it can lead to pathological changes in the *** impact of DON on human/animal health and animal productivity has thus attracted a great deal of attention around the *** causes severe damage to the intestine,including compromised intestinal barrier,mucosal damage,weakened immune function,and alterations in gut microbiota *** effects exacerbate intestinal infections and inflammation in livestock and poultry,posing adverse effects on overall ***,research into biological methods for DON detoxification is a crucial avenue for future *** includes the utilization of adsorption,enzymatic degradation,and other biological approaches to mitigate DON's impact,offering new strategies for prevention and treatment of DON-induced *** research will focus on identifying highly efficient detoxifying microorganisms or enzymes to reduce DON levels in food and feed,thereby mitigating its risks to both animals and human health.

关键词： deoxynivalenol(DON) intestinal barrier function mucus barrier immune function flora composition biological detoxification