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Journal of Thermal science 2024年第2期33卷 675-695页

作者： zhang Hao ZHAO Hongxia zhang Xiuao ZENG Hongxuan deng Jianqiang school of Energy and Power Engineering Shandong UniversityJi’nan250061China school of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an710049China

The steam ejector is a crucial component in the waste heat recovery *** performance determines the amount of recovered heat and system ***,poor ejector performance has always been the main bottleneck for system ***,this study proposes an optimization methodology to improve the steam ejector's performance by utilizing computational fluid dynamics(CFD) techniques,response surface methodology(RsM),and genetic algorithm(GA).Firstly,a homogeneous equilibrium model(HEM) was established to simulate the two-phase flow in the steam ***,the orthogonal test was presented to the screening of the key decision variables that have a significant impact on the entrainment ratio(ER).Next,the RsM was used to fit a response surface regression model(RsRM).Meanwhile,the effect of the interaction of geometric parameters on the performance of the steam ejector was ***,GA was employed to solve the RsRM's global optimal ER *** results show that the RsRM exhibits a good fit for ER(R^(2)=0.997).After RsM and GA optimization,the maximum ejector efficiency is 27.94%,which is 48.38% higher than the initial ejector of 18.83%.Furthermore,the optimized ejector efficiency is increased by 46.4% on average under off-design ***,the results reveal that the combination of CFD,RsM,and GA presents excellent reliability and feasibility in the optimization design of a two-phase steam ejector.

关键词： two-phase steam ejector optimization methodology CFD techniques response surface methodology genetic algorithm homogeneous equilibrium model

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synthesis of multifunctional additives for solid propellants:structure,properties and mechanism

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Defence Technology（防务技术） 2024年第3期33卷 308-316页

作者： Pingan zhang Lina sun Jianmin yuan Jianru deng College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082PR China College of Material science and Engineering Hunan UniversityChangsha 410082PR China Hu Bei sanjiang Aerospace Jianghe Chemical Technology Co. LtdYichang 444200PR China

To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB by adopting appropriate synthesis *** replacing 10% of HTPB binder in the propellant formulation,it can effectively enhance the interfacial bond strength between the propellant binder matrix and solid fillers(AP(ammonium perchlorate)and RDX(cyclotrimethylene-trinitramine)),the mechanical properties of the HTPB/AP/RDX/Al propellant were superior to blank control propellant with an improvement of 35.4% in tensile strength,62.0% enhancement in elongation at break,and reduce the propellant burn rate by 10.7% with any energy *** function mechanism of AEHTPB-CN was systematically elucidated through experiments and computer simulation *** results show that the tertiary amine group in AEHTPB-CN can react with AP to form ammonium ionic bonds,and the hydroxyl and cyano groups can form hydrogen bonding interactions with AP,which enables AEHTPB-CN to be firmly adsorbed on the AP surface through chemical and physical *** RDX,the interfacial bonding effect of AEHTPB-CN is attributed to their ability to form C-H···N≡C weak hydrogen bonding interaction between the cyano group and RDX methylene group.

关键词： Hydroxyl-terminated polybutadiene(HTPB) HTPB propellant Chemical modification Bonding agent Mechanism

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Constructions of optimal binary locally repairable codes via intersection subspaces

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science China(Information sciences) 2024年第6期67卷 418-432页

作者： Wenqin zhang deng TANG Chenhao yING yuan LUO school of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Locally repairable codes（LRCs）, which can recover any symbol of a codeword by reading only a small number of other symbols, have been widely used in real-world distributed storage systems, such as Microsoft Azure storage and Ceph storage Cluster. since binary linear LRCs can significantly reduce coding and decoding complexity, constructions of binary LRCs are of particular interest. The aim of this paper is to construct dimensional optimal binary LRCs with disjoint local repair groups. We introduce a method to connect intersection subspaces with binary LRCs and construct dimensional optimal binary linear LRCs with locality 2b（b 3） and minimum distance d 6 by employing intersection subspaces deduced from the direct sum. This method will sufficiently increase the number of possible repair groups of dimensional optimal LRCs, thus efficiently expanding the range of the construction parameters while keeping the largest code rates compared with all known binary linear LRCs with minimum distance d 6 and locality 2b.

关键词： locally repairable codes disjoint local repair groups distributed storage systems intersection subspaces direct sum

A New Vehicle Detection Framework Based on Feature-Guided in the Road scene

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Computers, Materials & Continua 2024年第1期78卷 533-549页

作者： Tianmin deng Xiyue zhang Xinxin Cheng school of Traffic and Transportation Chongqing Jiaotong UniversityChongqing400074China

Vehicle detection plays a crucial role in the field of autonomous driving ***,directly applying deep learning-based object detection algorithms to complex road scene images often leads to subpar performance and slow inference speeds in vehicle *** a balance between accuracy and detection speed is crucial for real-time object detection in real-world road *** paper proposes a high-precision and fast vehicle detector called the feature-guided bidirectional pyramid network(FBPN).Firstly,to tackle challenges like vehicle occlusion and significant background interference,the efficient feature filtering module(EFFM)is introduced into the deep network,which amplifies the disparities between the features of the vehicle and the ***,the proposed global attention localization module(GALM)in the model neck effectively perceives the detailed position information of the target,improving both the accuracy and inference speed of ***,the detection accuracy of small-scale vehicles is further enhanced through the utilization of a four-layer feature pyramid *** results show that FBPN achieves an average precision of 60.8% and 97.8% on the BDD100K and KITTI datasets,respectively,with inference speeds reaching 344.83 frames/s and 357.14 frames/*** demonstrates its effectiveness and superiority by striking a balance between detection accuracy and inference speed,outperforming several state-of-the-art methods.

关键词： Driverless car vehicle detection channel attention mechanism deep learning

Winter wheat yield improvement by genetic gain across different provinces in China

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Journal of Integrative Agriculture 2024年第2期23卷 468-483页

作者： Wei Chen Jingjuan zhang Xiping deng Key Laboratory of Disaster Monitoring and Mechanism simulating of shaanxi Province/school of Geography and Environment Baoji University of Arts and SciencesBaoji 721013China Centre for Crop and Food Innovation Murdoch University90 South StreetMurdochWA 6150Australia state Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F UniversityYangling 712100China

The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in *** on two sets of data,production yield from the National Bureau of statistics of China and experimental yield from literature,this study aims to(1)illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China,(2)explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China,and(3)compare the yield gap between experimental yield and production *** results show that both the production and experimental yields significantly increased along with the variety *** national annual yield increase ratio for the production yield was 1.67%from 1978 to 2018,varying from 0.96%in sichuan Province to 2.78%in Hebei Province;such ratio for the experimental yield was 1.13%from 1937 to *** yield gap between experimental and production yields decreased from the 1970s to the *** study reveals significant increases in some yield components consequent to variety replacement,including thousand-grain weight,kernel number per spike,and grain number per square meter;however,no change is shown in spike number per square *** biomass and harvest index consistently and significantly increased,whereas the plant height decreased significantly.

关键词： genetic gain winter wheat yield yield components

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special issue on electrochemical energy storage and conversion

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Frontiers in Energy 2024年第2期18卷 125-127页

作者： yun ZHENG Gaixia zhang sixu deng Jiujun zhang Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China Department of Electrical Engineering École de Technologie Supérieure(ÉTS)Universitédu QuébecMontréalH3C 1K3Canada Department of Chemical and Materials Engineering Concordia UniversityMontrealQC H3G 1M8Canada

The escalating global consumption of fossil fuels has significantly elevated the levels of CO_(2)in the atmosphere,leading to an undesirable global energy crisis and environmental *** deployment of renewable energy resources is crucial to mitigate these *** recent years,there has been noteworthy progress in electrochemical energy storage and conversion techniques and devices,including hydrogen energy and fuel cells,advanced energy storage and power batteries,and CO_(2)electrochemical conversion and utilization.

关键词： electrochemical energy elevated

Orthogonal waveform design with fractional programming on the ambiguity suppression of sAR systems

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science China(Information sciences) 2024年第9期67卷 263-279页

作者： yunkai deng yongwei zhang Zhimin zhang Wei WANG Heng zhang Department of space Microwave Remote sensing system Aerospace Information Research InstituteChinese Academy of Sciences

Waveform diversity(WD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, WD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar(sAR) *** these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density(PsD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio(CAR) and satisfactory imaging performance. Initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PsD variable, which sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PsD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in sAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization sAR systems.

关键词： synthetic aperture radar (sAR) waveform diversity (WD) ambiguity suppression orthogonal waveform fractional programming power spectrum density (PsD)

Dynamic thermal rating assessment of oil-immersed power transformers for multiple operating conditions

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High Voltage 2024年第1期9卷 195-205页

作者： Chen zhang Xuzhu Dong Jiangjun Ruan yongqing deng school of Electrical Engineering and Automation Wuhan UniversityWuhanHubeiChina

In this article,the dynamic thermal rating assessment method of oil-immersed power transformer with multiple operating conditions is proposed,considering the constraints of hot spot temperature(HsT),top oil temperature,losses of life and the maximum allowable current of on-load tap changer(OLTC)or bushing,which can determine the dynamic load curves under different operating conditions and give the most sensitive constraints to limit the dynamic load *** improve the accuracy of HsT estimation,the temperature estimation model is also improved and the thermal parameters are optimised using the HsT measured by optical ***,several application examples are studied for transformers in different *** results show that the normal cyclic dynamic transformer rating(DTR)is mainly limited by the losses of life when the ambient temperature is high,and the average load factor can be increased to 0.82 with a maximum load capacity of *** main limiting factor of short-term DTR is the OLTC or bushing current constraint,and the average load factor can be increased to *** maximum load capacity of the transformer under both operating conditions is 23%and 50%higher than its rated load capacity,indicating that the transformer still has a large load potential available.

关键词： load thermal power

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

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Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： Q.K.Liu L.deng Q.Wang X.zhang F.Q.Meng y.P.Wang y.Q.Gao H.B.Cai s.P.Zhu Graduate school China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China school of Nuclear science and Technology University of Science and Technology of ChinaHefei 230026China shanghai Institute of Laser Plasma Shanghai 201800China HEDPs Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China school of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BsRs)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BsRs evolution driven by broadband lasers.

关键词： scattering kinetic simplified

Energy Management of Price-maker Community Energy storage by stochastic Dynamic Programming

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CsEE Journal of Power and Energy systems 2024年第2期10卷 492-503页

作者： Lirong deng Xuan zhang Tianshu yang Hongbin sun yang Fu Qinglai Guo shmuel s.Oren Department of Electrical Engineering Shanghai University of Electric PowerShanghai 200000China Tsinghua-Berkeley shenzhen Institute Tsinghua UniversityShenzhen 518055China Department of Industrial Engineering and Operations Research University of California BerkeleyBerkeleyCAUSA Risk Analytics and Optimization Chair EPFLSwitzerlandand also with Power Systems LaboratoryETH Zurich8092 ZurichSwitzerland state Key Laboratory of Power systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

In this paper,we propose an analytical stochastic dynamic programming(sDP)algorithm to address the optimal management problem of price-maker community energy *** a price-maker,energy storage smooths price differences,thus decreasing energy arbitrage ***,this price-smoothing effect can result in significant external welfare changes by reduc-ing consumer costs and producer revenues,which is not negligible for the community with energy storage *** such,we formulate community storage management as an sDP that aims to maximize both energy arbitrage and community *** incorporate market interaction into the sDP format,we propose a framework that derives partial but sufficient market information to approximate impact of storage operations on market *** we present an analytical sDP algorithm that does not require state *** from computational efficiency,another advantage of the analytical algorithm is to guide energy storage to charge/discharge by directly comparing its current marginal value with expected future marginal *** studies indicate community-owned energy storage that maximizes both arbitrage and welfare value gains more benefits than storage that maximizes only *** proposed algorithm ensures optimality and largely reduces the computational complexity of the standard *** Terms-Analytical stochastic dynamic programming,energy management,energy storage,price-maker,social welfare.

关键词： Analytical stochastic dynamic programming energy management energy storage price-maker social welfare