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Optimizing urban block morphologies for net-zero energy cities:Exploring photovoltaic potential and urban design prototype

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Building Simulation 2024年第4期17卷 607-624页

作者： Xiaotian Geng dong xie Zhonghua Gou School of Urban Design Wuhan UniversityWuhanChina

The morphology of urban areas plays a crucial role in determining solar potential,which directly affects photovoltaic capacity and the achievement of net-zero *** study focuses on the City of Melbourne to investigate the utilization of solar energy across different urban densities and proposes optimized *** analysis encompasses blocks with diverse population densities,examining medium and high-density *** utilizing a multi-objective genetic optimization approach,the urban morphology of these blocks is *** findings indicate that low-density blocks exhibit photovoltaic potential ranging from 1 to 6.6 times their total energy *** and high-density blocks achieve photovoltaic potential levels approximately equivalent to 40%-85%of their overall energy ***,significant variations in photovoltaic potential are observed among different urban forms within medium and high-density ***“elevated corners with central valley”prototype is proposed as an effective approach,enhancing the overall photovoltaic potential by approximately 14%.This study introduces novel analytical concepts,shedding light on the intricate relationship between urban morphologies and photovoltaic potential.

关键词： net-zero energy solar energy urban density urban morphology multi-objective optimization photovoltaic potential

Quantum estimation of detection efficiency with no-knowledge quantum feedback

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Chinese Physics B 2018年第6期27卷 151-155页

作者： dong xie Chunling Xu Faculty of Science Guilin University of Aerospace Technology Guilin 541004 China

We investigate that no-knowledge measurement-based feedback control is utilized to obtain the estimation precision of the detection efficiency. We show that no-knowledge measurement is the optimal way to estimate the detection *** higher precision can be achieved for the lower or larger detection efficiency. It is found that no-knowledge feedback can be used to cancel decoherence. No-knowledge feedback with a high detection efficiency can perform well in estimating frequency and detection efficiency parameters simultaneously; simultaneous estimation is better than independent estimation given by the same probes.

关键词： no-knowldege feedback parameter estimation simultaneous measurement

Sign-changing Solutions to Nonlinear Elliptic Equations with Hardy Potential and Critical Parameter in R^2

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Acta Mathematicae Applicatae Sinica 2019年第3期35卷 689-694页

作者： Chao-dong xie Zhi-hui CHEN School of Economics&Management Guizhou University for Ethinic MinoritiesGuizhou 550025China chool of Mathematics South China University of TechnologyGuangzhou 510640China

In this paper,a new Hilbert space is defined which is embedded into W01,q(Ω)for 1≤q<*** using sign-changing critical point theory,we prove the existence of infinitely many sign-changing solutions in this new space f... 详细信息

关键词： elliptic PDE sign-changing solution critical point

Adaptive vertical handoff algorithm in heterogeneous networks

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The Journal of China Universities of Posts and Telecommunications 2007年第1期14卷 22-25,44页

作者： xie Sheng-dong WU Meng Communication and Information Engineering Institute Nanjing University of Posts and Telecommunications Nanjing 210003 China

The integration of cellular network （CN） and wireless local area network （WLAN） is the trend of the next generation mobile communication systems, and nodes will handoff between the two kinds of networks. The received signal strength （RSS） is the dominant factor considered when handoff occurs. In order to improve the handoff efficiency, this study proposes an adaptive decision algorithm for vertical handoff on the basis of fast Fourier transform （FFT）. The algorithm makes handoff decision after analyzing the signal strength fluctuation which is caused by slow fading through FFT. Simulations show that the algorithm reduces the number of handoff by 35%, shortens the areas influenced by slow fading, and enables the nodes to make full use of WLAN in communication compared with traditional algorithms.

关键词： vertical handoff signal strength slow fading fast Fourier transform

Non-Fourier heat conduction induced thermal shock fracture behavior of multi-crack auxetic honeycomb structures

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Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2093-2112页

作者： Junsong HU Baoling WANG Yang YANG dong xie School of Civil Engineering University of South China Key Lab of Hunan for the Technologies of Energy Conservation in Prefabricated Buildings School of Science Harbin Institute of TechnologyShenzhen

The investigation of non-Fourier thermal shock fracture behavior in multicrack auxetic honeycomb structures(HSs) is presented. By employing a non-Fourier heat conduction model, the corresponding temperature and thermal stress fields are established. Subsequently, a thermal stress intensity factor(TSIF) model for the auxetic HSs,accounting for multi-crack interactions, is developed. Finally, using the fracture-based failure criterion, the non-Fourier multi-crack critical temperature of the auxetic HSs is determined. This investigation thoroughly examines the effects of the non-Fourier effect(NFE), auxetic property, crack spacing, and crack location on the thermal shock fracture behavior of the auxetic HSs. Results indicate that a stronger NFE leads to weaker thermal shock resistance in auxetic HSs. Regardless of the presence of the NFE, the auxetic property consistently increases the multi-crack critical temperature of the ***, the interaction of multi-crack inhibits thermal shock crack propagation in HSs.

关键词： 45E05 auxetic honeycomb structure (HS) multi-crack non-Fourier effect (NFE) O343 thermal shock fracture

Quantum metrology with coherent superposition of two different coded channels

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Chinese Physics B 2021年第9期30卷 111-116页

作者： dong xie Chunling Xu Anmin Wang College of Science Guilin University of Aerospace TechnologyGuilin 541004China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

We investigate the advantage of coherent superposition of two different coded channels in quantum *** a continuous variable system,we show that the Heisenberg limit 1/N can be beaten by the coherent superposition without the help of indefinite causal *** in parameter estimation,we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum switch which can generate indefinite causal *** analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as 1/N^(m) for m≥*** results can help to construct a high-precision measurement equipment,which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation.

关键词： quantum metrology quantum switch quantum Fisher information coherent superposition

Kinetics of magnesium preparation by vacuum-assisted carbothermic reduction method

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Rare Metals 2016年第2期35卷 192-197页

作者： Wei-dong xie Jie Chen Hao Wang Xi Zhang Xiao-dong Peng Yan Yang School of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University Bai He Tan Project Department Yangtze Three Gorges Technology & Economy Development Co. Ltd

Metallic magnesium was prepared by vacuumassisted carbothermic reduction method, and its morphologies were observed and analyzed. The reduction ratios of reactions were carried out under various vacuums, reaction temperatures, and time. Reaction kinetics of carbothermic reduction process was investigated. The results reveal that the morphologies of metallic magnesium sample that crystallized in the bottom and top sections of the condensation cap appear as the shape of feather with close-packing needle structure and the shape of schistose with metal luster,compactly clumpy structure, respectively. The reduction ratio of reaction process can be facilitated through reducing vacuum, increasing temperature, lengthening time, or their combinations and can reach up to 83.7 % under the condition of 10 Pa and 1573 K with 60 min reaction time. At1423-1573 K, the reaction rate constant k of carbothermic reduction of magnesia in vacuum gets greater with the increase of temperature. The reaction activity energy is190.28, 219.71 and 451.12-528.54 k J mol-1when the procedure of carbon gasification reaction, interfacial reaction, or gaseous diffusion is the reaction rate-determining step at 1423-1573 K, respectively. The gaseous diffusion procedure has the largest activity energy value and is,therefore, the main reaction rate-determining step.

关键词： Magnesium Carbothermic reduction Magnesia Vacuum Kinetics

Microstructure, mechanical properties, and corrosion resistance of Mg–9Li–3Al–1.6Y alloy

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Rare Metals 2016年第5期35卷 374-379页

作者： Hao-Miao Yang Nan-Yi Zhang Na Liu Wei-dong xie Xiao-dong Peng College of materials Science and Engineering Chongqing University School of Physics & Electron Engineering Yangtze Normal University

Mg–9Li–3Al–1.6Y alloys were prepared through mixture method. The microstructure, mechanical properties, and corrosion resistance of the as-cast and asextruded alloys were studied by optical microscopy（OM）,scanning electronic microscopy（SEM）, X-ray diffraction（XRD）, mechanical properties testing, and electrochemical measurement. The as-cast Mg–9Li–3Al–1.6Y alloy with the average grain size of 325 lm is composed of b-Li matrix, block a-Mg, and granule Al2Y phases. After extrusion, the grain size of the as-cast alloy is obviously refined and reaches to 75 lm; the strength and elongation of the extruded alloy are enhanced by 17.20 % and49.45 %, respectively, owing to their fine microstructure and reduction of casting defects. The as-extruded alloy shows better corrosion resistance compared to the as-cast one, which may be related to the low stored energy and dislocation density in the extruded alloy, also the homogenization treatment before extrusion.

关键词： Magnesium alloy Microstructures Mechanical properties Corrosion resistance

SCTP performance improvement based on virtual receiver window

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The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 67-72页

作者： WANG Feng-hua xie dong-liang ZHANG Peng State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications

This article puts forward one algorithm for stream control transfer protocol （SCTP） improvement with limited receiver buffer （RBUF）. As is well known, SCTP is one of the most important transfer control protocol, but most researches focus on the situations without the RBUF limit. In this study, we analyze the impact of the RBUF size on the performance. Computer simulations show that the network utility is low in reliable transfer, when the RBUF size is smaller than bandwidth delay product. By studying the transmission sequence number （TSN） transfer progress, we find that the peer receiver window （PEER_RWND）, which lags behind the true receiver window （RWND）, leads to the poor network utility. To improve SCTP performance with limited RBUF, the virtual receiver window （VIRTUAL_RWND） is introduced. Based on the VIRTUAL_RWND, one algorithm is proposed to increase the sending rate. Computer simulations have evaluated an excellent performance of the proposed algorithm at both ideal link without lost packet and nonideal link with lost packet.

关键词： SCTP limited receiver buffer VIRTUAL_RWND