检索结果-南通市图书馆

Thermal stability enhancement and prediction by ANN model

在线全文

学校读者我要写书评

暂无评论

Energy and AI 2024年第2期16卷 125-136页

作者： Ziyu liu Xiaoyi yang School of Energy and Power Engineering Energy and Environment International CenterBeihang UniversityBeijing100191China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Supersonic aircraft requires thermal endurance of aviation fuel in the process of cooling engine and aircraft. As the composition of petroleum-based jet fuel (RP-3) is confined by crude oil and refining process, sustainable alternative jet fuel with green house gas reduction become to undertake the composition optimization for improving thermal stability. For designing aviation fuel with robust thermal stability and the detail understanding of thermal stability mechanism, RP-3, Fischer–Tropsch fuel, and additives with cyclic structure for absorbing free radical, were investigated thermal stability by modifying different blend ratios under different conditions. Thermal endurance degree was assessed by chroma and deposition tendency. FT blend with cyclic hydrocarbon can improve thermal endurance degree. In compliance with individual optimized blend ratio, the contribution follows methyl cyclopentane > decalin > methyl cyclohexane > tetralin > n-propyl-benzene > 1,2.4 trimethyl-benzene. The appropriate blend ratio could undertake hydrogen donors for terminating the propagation of oxygen-carrying radical, but hydrocarbons with cyclic structure could enhance deposition tendency. Methyl cyclopentane and its oxidation derivatives take the roles of solvent by anti-polymerization and hydrogen donor by opening cyclic structure in the thermal endurance process, and thus lead to a wide range of blend ratio for improving significantly thermal stability. β-scission leading to C–C bond cleavage is the major reaction at the early decomposition stage, which resulted in most abundant derivatives plus C2. The effects of additives on thermal stability are complex and nonlinear on the tendency of thermal deposits and thermal endurance degree, and thus the appropriate ANN-thermal stability model has been trained based on the experiment data and can achieve above 0.995 correlation coefficient. ANN - thermal stability model can predict not only the content of derivatives including ester, o

关键词： Sustainable jet fuel Thermal stability ANN Thermal endurance Fuel pyrolysis

Progress on the program of Si-compatible two-dimensional semiconductor materials and devices

维普期刊数据库评论

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(Information Sciences) 2024年第6期67卷 152-171页

作者： Mingsheng XU Yuwei WANG Jiwei liu Deren yang College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University

Two-dimensional(2.) materials are at the forefront of innovation, heralding a new era for nextgeneration electronics and optoelectronics. These materials are distinguished by their unique structural characteristics: they have no hanging bonds on their surface, exhibit weakened electrostatic shielding in the Z-direction, and boast atomic thickness in their monolayers. These features have led to groundbreaking discoveries in electrical, optical, and magnetic properties, paving the way for advancements in low-power electronics, valleytronics, infrared detectors, and memory devices. Despite these promising developments,Si-based technologies continue to dominate the landscape of next-generation electronics and optoelectronics,as well as heterogeneous integration. In response to this ongoing evolution, the National Natural Science Foundation of China(NSFC) initiated a major program in 2.2. dubbed “Si-compatible two-dimensional semiconductor materials and devices”. This study reviews the progress made under the NSFC Program,spotlighting its main achievements and outlining key future research directions. Additionally, it sheds light on the challenges that researchers in the 2. domain face, particularly in developing Si-compatible 2. technologies.

关键词： two-dimensional materials Si-based CMOS technologies electronics and optoelectronics heterogeneous integration low-power

Adaptive multi-channel Bayesian graph attention network for IoT transaction security

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Digital Communications and Networks 2024年第3期10卷 631-644页

作者： Zhaowei liu Dong yang Shenqiang Wang Hang Su School of Computer and Control Engineering Yantai UniversityYantai264005China Department of Electronics Information and BioengineeringPolitecnico di MilanoMilan20133Italy

With the rapid advancement of 5G technology,the Internet of Things(IoT)has entered a new phase of appli-cations and is rapidly becoming a significant force in promoting economic *** to the vast amounts of data created by numerous 5G IoT devices,the Ethereum platform has become a tool for the storage and sharing of IoT device data,thanks to its open and tamper-resistant ***,Ethereum account security is necessary for the Internet of Things to grow quickly and improve people's *** modeling Ethereum trans-action records as a transaction network,the account types are well identified by the Ethereum account classifi-cation system established based on Graph Neural Networks(GNNs).This work first investigates the Ethereum transaction ***,experimental metrics reveal that the Ethereum transaction network is neither optimal nor even satisfactory in terms of accurately representing transactions per *** flaw may significantly impede the classification capability of GNNs,which is mostly governed by their *** work proposes an Adaptive Multi-channel Bayesian Graph Attention Network(AMBGAT)for Ethereum account clas-sification to address this *** uses attention to enhance node features,estimate graph topology that conforms to the ground truth,and efficiently extract node features pertinent to downstream *** extensive experiment with actual Ethereum transaction data demonstrates that AMBGAT obtains competitive performance in the classification of Ethereum accounts while accurately estimating the graph topology.

关键词： Internet of things Graph representation learning Node classification Security mechanism

Regulating Effect of Substrate Temperature on Sputteringgrown Ge/Si QDs under Low Ge Deposition

维普期刊数据库评论

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 Wuhan University of Technology(Materials Science) 2024年第4期39卷 888-894页

作者：舒启江 yang Linjing liu Hongxing 黄鹏儒 Institute of Information Yunnan University of Chinese MedicineKunming 650500China Guangxi Key Laboratory of Information Materials and Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials School of Material Science&EngineeringGuilin University of Electronic TechnologyGuilin 541004China

The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectroscopy,and photoluminescence(PL)*** experimental results indicate that temperatures higher than 750℃effectively increase the crystallization rate and surface smoothness of the Si buffer layer,and temperatures higher than 600℃significantly enhance the migration ability of Ge atoms,thus increasing the probability of Ge atoms meeting and nucleating to form QDs on Si buffer layer,but an excessively high temperature will cause the QDs to undergo an Ostwald ripening process and thus develop into super large *** addition,some PL peaks were observed in samples containing small-sized,high-density Ge QDs,the photoelectric properties reflected by these peaks were in good agreement with the corresponding structural characteristics of the grown *** results demonstrate the viability of preparing high-quality QDs by magnetron sputtering at high deposition rate,and the temperature effect is expected to work in conjunction with other controllable factors to further regulate QD growth,which paves an effective way for the industrial production of QDs that can be used in future devices.

关键词： Ge/Si QDs deposition temperatures evolution law photoelectric performance

On the Probability of Generating a Primitive Matrix

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第4期37卷 1755-1771页

作者： CHEN Jingwei FENG Yong liu yang WU Wenyuan Chongqing Key Laboratory of Automated Reasoning and Cognition Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Chongqing College University of Chinese Academy of SciencesChongqing 400714China Key Laboratory of Advanced Manufacturing Technology of Ministry of Education Guizhou UniversityyGuiyang 550025China Information Science and Engineering Chongqing Jiaotong UniversityChongqing 400074China

Given a k×n integer primitive matrix A(i.e.,a matrix can be extended to an n×n unimodular matrix over the integers)with the maximal absolute value of entries‖A‖bounded by an integer λ from above,the authors study the probability that the m×n matrix extended from A by appending other m-k row vectors of dimension n with entries chosen randomly and independently from the uniform distribution over{0,1,…,λ-1}is still *** authors present a complete and rigorous proof of a lower bound on the probability,which is at least a constant for fixed m in the range[k+1,n-4].As an application,the authors prove that there exists a fast Las Vegas algorithm that completes a k×n primitive matrix A to an n×n unimodular matrix within expected O(n^(ω)log‖A‖)bit operations,where O is big-O but without log factors,ω is the exponent on the arithmetic operations of matrix multiplication.

关键词： Integer matrix matrix completion probabilistic algorithm unimodular matrix

A heat transfer model for liquid film boiling on micro-structured surfaces

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第5期11卷 352-364页

作者： Pengkun Li Qifan Zou Xiuliang liu Ronggui yang School of Energy and Power Engineering Huazhong University of Science and Technology State Key Laboratory of Coal Combustion Huazhong University of Science and Technology

High heat transfer coefficient(HTC) and critical heat flux(CHF) are achieved in liquid film boiling by coupling vibrant vapor bubbles with a capillary liquid film, which has thus received increased interest for thermal management of high-power electronics. Although some experimental progress has been made, a high-fidelity heat transfer model for liquid film boiling is lacking. This work develops a thermal-hydrodynamic model by considering both evaporation atop the wick and nucleate boiling inside the wick to simultaneously predict the HTC and CHF. Nucleate boiling is modeled with microlayer evaporation theory, where a unified scaling factor is defined to characterize the change of microlayer area with heat flux. The scaling factor η is found to be independent of wicking structure and can be determined from a few measurements. This makes our model universal to predict the liquid film boiling heat transfer for various micro-structured surfaces including micropillar, micropowder, and micromesh. This work not only sheds light on understanding fundamental mechanisms of phase-change heat transfer, but also provides a tool for designing micro-structured surfaces in thermal management.

关键词： liquid film boiling heat transfer model critical heat flux heat transfer coefficient thermal management

Path Planning and Tracking Control for Parking via Soft Actor-Critic Under Non-Ideal Scenarios

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 181-195页

作者： Xiaolin Tang Yuyou yang Teng liu Xianke Lin Kai yang Shen Li IEEE the College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China the Clinical Research Center and Medical Pathology Center Chongqing University Three Gorges HospitalChongqing UniversityWanzhou 404000 the Department of Automotive and Mechatronics Engineering Ontario Tech UniversityOshawa ON LIG OC5Canada the School of Civil Engineering Tsinghua UniversityBeijing 100084China

Parking in a small parking lot within limited space poses a difficult task. It often leads to deviations between the final parking posture and the target posture. These deviations can lead to partial occupancy of adjacent parking lots, which poses a safety threat to vehicles parked in these parking lots. However, previous studies have not addressed this issue. In this paper, we aim to evaluate the impact of parking deviation of existing vehicles next to the target parking lot(PDEVNTPL) on the automatic ego vehicle(AEV) parking, in terms of safety, comfort, accuracy, and efficiency of parking. A segmented parking training framework(SPTF) based on soft actor-critic(SAC) is proposed to improve parking performance. In the proposed method, the SAC algorithm incorporates strategy entropy into the objective function, to enable the AEV to learn parking strategies based on a more comprehensive understanding of the environment. Additionally, the SPTF simplifies complex parking tasks to maintain the high performance of deep reinforcement learning(DRL). The experimental results reveal that the PDEVNTPL has a detrimental influence on the AEV parking in terms of safety, accuracy, and comfort, leading to reductions of more than 2.%, 54%, and 2.%respectively. However, the SAC-based SPTF effectively mitigates this impact, resulting in a considerable increase in the parking success rate from 71% to 93%. Furthermore, the heading angle deviation is significantly reduced from 2.2. degrees to 0.43degrees.

关键词： Automatic parking control strategy parking deviation(APS) soft actor-critic(SAC)

Data-driven Reactive Power Optimization of Distribution Networks via Graph Attention Networks

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 874-885页

作者： Wenlong Liao Dechang yang Qi liu Yixiong Jia Chenxi Wang Zhe yang Wind Engineering and Renewable Energy Laboratory Ecole Polytechnique Federale de Lausanne(EPFL)Lausanne 1015Switzerland the College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China the Department of Electrical and Electronic Engineering(Energy Digitalization Laboratory) The University of Hong KongHong KongChina the Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong KongChina

Reactive power optimization of distribution networks is traditionally addressed by physical model based methods,which often lead to locally optimal solutions and require heavy online inference time *** improve the quality of the solution and reduce the inference time burden,this paper proposes a new graph attention networks based method to directly map the complex nonlinear relationship between graphs(topology and power loads)and reactive power scheduling schemes of distribution networks,from a data-driven *** graph attention network is tailored specifically to this problem and incorporates several innovative features such as a self-loop in the adjacency matrix,a customized loss function,and the use of max-pooling ***,a rulebased strategy is proposed to adjust infeasible solutions that violate *** results on multiple distribution networks demonstrate that the proposed method outperforms other machine learning based methods in terms of the solution quality and robustness to varying load ***,its online inference time is significantly faster than traditional physical model based methods,particularly for large-scale distribution networks.

关键词： Reactive power optimization graph neural network distribution network machine learning data-driven

Bionic Design and Experimental Validation of a Robotic Airship Inspired by the Physalia physalis

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第2期21卷 740-753页

作者： Yueneng yang Lili Chen Zhiyang {2. Shifeng Zhang College of Aerospace Science and Engineering National University of Defense TechnologyNo.109Deya RoadKaiFu DistrictChangsha410073China Aerospace Technology Institute China Aerodynamics Research and Development CenterMianyang621000China

The robotic airship is one of the most unique and promising green aircraft,however,as a“lighter-than-air aircraft”and“thermal aircraft”,its long-endurance flight has great difficulties in decreasing drag and controlling buoyancy and pressure under thermal *** this work,we reported a robotic airship inspired by the Physalia physalis,imitating its morphology,physiological structure,and biological *** hull is designed by imitating the morphology of the Physalia physalis,and the gasbags including a helium balloon,two ballonets,and a thermoregulation gasbag are designed by imitating the physiological structure and biological behaviors of the pneumatophore,bladder,and gland of the Physalia physalis,*** results show that the bionic airship has an increase of about 40%in lift-to-drag and decreases the pressure in helium balloon by 47.5%under thermal effects,and has better aerodynamic performances and thermoregulation performances than conventional airships.

关键词： Robotic airship Bionic design Aerodynamic performances Thermoregulation Physalia physalis