SwePub - sökning: WFRF:(Wang Wenlong)

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1.	Luo, Yifei, et al. (författare) Technology Roadmap for Flexible Sensors 2023 Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295 Forskningsöversikt (refereegranskat)abstract Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
2.	Liao, Wenlong, et al. (författare) A Review of Graph Neural Networks and Their Applications in Power Systems 2022 Ingår i: Journal of Modern Power Systems and Clean Energy. - : Journal of Modern Power Systems and Clean Energy. - 2196-5625 .- 2196-5420. ; 10:2, s. 345-360 Forskningsöversikt (refereegranskat)abstract Deep neural networks have revolutionized many machine learning tasks in power systems, ranging from pattern recognition to signal processing. The data in these tasks are typically represented in Euclidean domains. Nevertheless, there is an increasing number of applications in power systems, where data are collected from non-Euclidean domains and represented as graph-structured data with high-dimensional features and interdependency among nodes. The complexity of graph-structured data has brought significant challenges to the existing deep neural networks defined in Euclidean domains. Recently, many publications generalizing deep neural networks for graph-structured data in power systems have emerged. In this paper, a comprehensive overview of graph neural networks (GNNs) in power systems is proposed. Specifically, several classical paradigms of GNN structures, e.g., graph convolutional networks, are summarized. Key applications in power systems such as fault scenario application, time-series prediction, power flow calculation, and data generation are reviewed in detail. Furthermore, main issues and some research trends about the applications of GNNs in power systems are discussed.
3.	Liao, Wenlong, et al. (författare) Scenario Generation for Cooling, Heating, and Power Loads Using Generative Moment Matching Networks 2022 Ingår i: CSEE JOURNAL OF POWER AND ENERGY SYSTEMS. - : Power System Technology Press. - 2096-0042. ; 8:6, s. 1730-1740 Tidskriftsartikel (refereegranskat)abstract Scenario generations of cooling, heating, and power loads are of great significance for the economic operation and stability analysis of integrated energy systems. In this paper, a novel deep generative network is proposed to model cooling, heating, and power load curves based on generative moment matching networks (GMMNs) where an auto-encoder transforms high-dimensional load curves into low-dimensional latent variables and the maximum mean discrepancy represents the similarity metrics between the generated samples and the real samples. After training the model, the new scenarios are generated by feeding Gaussian noises to the scenario generator of the GMMN. Unlike the explicit density models, the proposed GMMN does not need to artificially assume the probability distribution of the load curves, which leads to stronger universality. The simulation results show that the GMMN not only fits the probability distribution of multi-class load curves very well, but also accurately captures the shape (e.g., large peaks, fast ramps, and fluctuation), frequency-domain characteristics, and temporal-spatial correlations of cooling, heating, and power loads. Furthermore, the energy consumption of generated samples closely resembles that of real samples.
4.	Wang, Chaoqian, et al. (författare) A stepwise microwave synergistic pyrolysis approach to produce sludge-based biochars : Feasibility study simulated by laboratory experiments 2020 Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 272, s. 1-10 Tidskriftsartikel (refereegranskat)abstract A stepwise microwave synergistic pyrolysis (SMSP) approach is proposed as a new way to relieve disposal problems of the sewage sludge. Here the sludge is first pre-pyrolyzed by a conventional heating stage, and then rapidly pyrolyzed by a microwave-induced heating stage without any extra microwave absorbers or blending needed. Under simulated process pyrolysis conditions, the dried sludge, intermediate and final sludge-based biochar samples were prepared in the laboratory. Their chemical composition, microstructure and morphology, and leaching toxicity of heavy metals were carefully characterized and analyzed by various techniques such as proximate and ultimate analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), and scanning electron microscope equipped with energy-dispersive x-ray spectroscopy (SEM-EDX). Results showed that the pre-pyrolytic biochar can be rapidly heated up to 1100 °C within 5 min under microwave irradiation. The pre-pyrolytic stage increased the carbonization and ash enrichment degree of the sludge which itself acted as a good microwave absorber while achieving a quick temperature rise under microwave irradiation. The ash remaining ratio and the specific surface area of the biochar derived from the SMSP approach (labelled as SBC2) are increased by 6.46% and 16.17% respectively, compared with the conventional biochar sample (SBC1). And SBC2 still had diverse surface functional groups kept after SMSP. The residual ratios of Ni, Cu, Zn, Pb, Cr and Cd in SBC2 was more noticeable than in SBC1 but the leaching ratios quite the contrary. Vitrification is also well proved by the increment of quartz peak detected by XRD tests, and the formation of melted glassy spheres with elemental composition of Si, Ca, Al observed by SEM-EDX. It can favorably increase solidification level and decrease leaching toxicity of heavy metals in the SBC2. The feasibility of this proposed SMSP concept has been positively supported by our experimental results. The properties of the sludge-based biochar produced from the SMSP approach also show great potential to be utilized as precursors to produce various adsorbents.
5.	Gao, Lihua, et al. (författare) Interfacial phenomenon and Marangoni convection of Fe–C melt on coke substrate under in situ observation 2023 Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1 Tidskriftsartikel (refereegranskat)abstract The interfacial phenomenon between liqiuid iron and coke is important for determining the melting efficiency in the blast furnace iron-making process. In this study, the interaction observed in the case of the iron-carbon (Fe–C) melt on coke substrate was investigated using a high-temperature vacuum wettability test equipment. The Fe–C melt did not wet and spread on the coke substrate with different graphitization degrees (r 0) at a high temperature of 1450 °C. The contact angles changed from 124.5° to 105.3°, and the r 0 increased from 9.30 to 50.00%, thus indicating a nonwetting state. The deepening of graphitization decreased the contact angle. Thereby, increasing the contact area between liquid iron and the carbonaceous material, which facilitated carbon dissolution. The irregular movements of Fe–C melt were observed in situ during the wetting process. The horizontal force of the droplet caused by interfacial tension and the contact angle; the Marangoni convection owing to the gradient of carbon concentration; and the impulse force caused by the generation, aggregation, and release of SiO bubbles at the interface were attributed to the driving force.
6.	Hoffmann, Thomas J, et al. (författare) Genome-wide association study of prostate-specific antigen levels in 392,522 men identifies new loci and improves cross-ancestry prediction 2023 Annan publikation (övrigt vetenskapligt/konstnärligt)abstract We conducted a multi-ancestry genome-wide association study of prostate-specific antigen (PSA) levels in 296,754 men (211,342 European ancestry; 58,236 African ancestry; 23,546 Hispanic/Latino; 3,630 Asian ancestry; 96.5% of participants were from the Million Veteran Program). We identified 318 independent genome-wide significant (p≤5e-8) variants, 184 of which were novel. Most demonstrated evidence of replication in an independent cohort (n=95,768). Meta-analyzing discovery and replication (n=392,522) identified 447 variants, of which a further 111 were novel. Out-of-sample variance in PSA explained by our new polygenic risk score reached 16.9% (95% CI=16.1%-17.8%) in European ancestry, 9.5% (95% CI=7.0%-12.2%) in African ancestry, 18.6% (95% CI=15.8%-21.4%) in Hispanic/Latino, and 15.3% (95% CI=12.7%-18.1%) in Asian ancestry, and lower for higher age. Our study highlights how including proportionally more participants from underrepresented populations improves genetic prediction of PSA levels, with potential to personalize prostate cancer screening.
7.	Kevrekidis, P. G., et al. (författare) Adiabatic invariant analysis of dark and dark-bright soliton stripes in two-dimensional Bose-Einstein condensates 2018 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 97:6 Tidskriftsartikel (refereegranskat)abstract In the present work, we develop an adiabatic invariant approach for the evolution of quasi-one-dimensional (stripe) solitons embedded in a two-dimensional Bose-Einstein condensate. The results of the theory are obtained both for the one-component case of dark soliton stripes, as well as for the considerably more involved case of the two-component dark-bright (alias "filled dark") soliton stripes. In both cases, analytical predictions regarding the stability and dynamics of these structures are obtained. One of our main findings is the determination of the instability modes of the waves as a function of the parameters of the system (such as the trap strength and the chemical potential). Our analytical predictions are favorably compared with results of direct numerical simulations.
8.	Kevrekidis, P. G., et al. (författare) Dynamics of interacting dark soliton stripes 2019 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 100:3 Tidskriftsartikel (refereegranskat)abstract In the present work we examine the statics and dynamics of multiple parallel dark soliton stripes in a two-dimensional Bose-Einstein condensate. Our principal goal is to study the effect of the interaction between the stripes on the transverse instability of the individual stripes. The cases of two-, three-, and four-stripe states are studied in detail. We use a recently developed adiabatic invariant formulation to derive a quasianalytical prediction for the stripe equilibrium position and for the Bogoliubov-de Gennes spectrum of excitations of stationary stripes. We subsequently test our predictions against numerical simulations of the full two-dimensional Gross-Pitaevskii equation. We find that the number of unstable eigenmodes increases as the number of stripes increases due to (unstable) relative motions between the stripes. Their corresponding growth rates do not significantly change, although for large chemical potentials, the larger the stripe number, the larger the maximal instability growth rate. The instability induced dynamics of multiple stripe states and their decay into vortices are also investigated.
9.	Li, Bo, et al. (författare) Thermal management performance improvement of phase change material for autonomous underwater vehicles' battery module by optimizing fin design based on quantitative evaluation method 2022 Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 46:11, s. 15756-15772 Tidskriftsartikel (refereegranskat)abstract Efficient thermal management of lithium battery modules has become a thorny problem in the development of autonomous underwater vehicles (AUVs), especially under high current discharge. In this article, the fin/phase change material (PCM) composite structure was proposed for AUV's battery thermal management with consideration of natural convection. The temperature behavior of the battery and the melting behavior of PCM were investigated under different key parameters. In addition, the heat transfer mechanism of the melting process of the PCM was revealed. More importantly, the dimensionless temperature control performance (TCP) factor and the dimensionless heat storage performance (HSP) factor were introduced as new criteria to quantitatively evaluate the impact of different design parameters on the battery thermal management performance. The results showed that utilizing fins can significantly accelerate the melting of the PCM. Increasing the number of fins can reduce the temperature of the battery and improve the uniformity of the battery temperature distribution. Compared with the pure PCM, the total time required for PCM melting in the fin/PCM battery thermal management unit with different numbers of fins is reduced by at least 11.5%. The decrease of the time of complete PCM melting is not linearly correlated with the length ratio of fins. The fin number of N = 6, length ratio of R = 0.8, and angle between fins of φ = 36° were identified as the optimal parameters of fin/PCM composite structures. The TCP and HSP were enhanced by 38.1% and 4.54%, respectively. The conclusions of this work can provide reference for the accurate design of fin/PCM composite structures for the thermal management of AUV batteries. Highlights: The fin/phase change material composite structure was introduced for autonomous underwater vehicles' battery thermal management. The temperature and melting behavior were investigated with natural convection. The temperature control performance factor and heat storage performance factor were proposed as new evaluation criteria. Temperature deviation index was used to measure the battery temperature uniformity. The performance was enhanced by optimizing the design parameters of fin.
10.	Li, Qishuang, et al. (författare) Identification of the cytochrome P450s responsible for the biosynthesis of two types of aporphine alkaloids and their de novo biosynthesis in yeast 2024 Ingår i: Journal of Integrative Plant Biology. - 1672-9072 .- 1744-7909. ; In Press Tidskriftsartikel (refereegranskat)abstract Aporphine alkaloids have diverse pharmacological activities; however, our understanding of their biosynthesis is relatively limited. Previous studies have classified aporphine alkaloids into two categories based on the configuration and number of substituents of the D-ring and have proposed preliminary biosynthetic pathways for each category. In this study, we identified two specific cytochrome P450 enzymes (CYP80G6 and CYP80Q5) with distinct activities toward (S)-configured and (R)-configured substrates from the herbaceous perennial vine Stephania tetrandra, shedding light on the biosynthetic mechanisms and stereochemical features of these two aporphine alkaloid categories. Additionally, we characterized two CYP719C enzymes (CYP719C3 and CYP719C4) that catalyzed the formation of the methylenedioxy bridge, an essential pharmacophoric group, on the A- and D-rings, respectively, of aporphine alkaloids. Leveraging the functional characterization of these crucial cytochrome P450 enzymes, we reconstructed the biosynthetic pathways for the two types of aporphine alkaloids in budding yeast (Saccharomyces cerevisiae) for the de novo production of compounds such as (R)-glaziovine, (S)-glaziovine, and magnoflorine. This study provides key insight into the biosynthesis of aporphine alkaloids and lays a foundation for producing these valuable compounds through synthetic biology.
11.	Liao, Wenlong, et al. (författare) An Open-Source Toolbox with Classical Classifiers for Electricity Theft Detection 2021 Ingår i: 2021 IEEE 2nd China International Youth Conference on Electrical Engineering, CIYCEE 2021. - : Institute of Electrical and Electronics Engineers Inc.. Konferensbidrag (refereegranskat)abstract Recently, there is increasing interest in detecting electricity thieves for economic benefits for power companies, and many works aim to improve the accuracy of electricity theft detection. Nevertheless, a core obstacle that currently hinders the direct comparison of classifiers for electricity theft detection is the lack of a standard and public dataset, since fraudulent power load profiles are usually difficult to collect for various reasons, including cost, cumber, and confidentiality. Therefore, this paper presents an open-source toolbox, which generates different kinds of fraudulent power load profiles from attack models, and integrates classical classifiers (e.g., support vector machine, multi-layer perceptron, convolutional neural network, long short-term memory, bidirectional long short-term memory) with different performance as baselines for the comparison with new algorithms. Users can easily generate datasets and modify parameters of classical classifiers guided by user friendly interactive interfaces. The codes, toolbox, and user manuals are available online and it is free to use and extend them.
12.	Liao, Wenlong, et al. (författare) Data-driven Missing Data Imputation for Wind Farms Using Context Encoder 2022 Ingår i: Journal of Modern Power Systems and Clean Energy. - : Journal of Modern Power Systems and Clean Energy. - 2196-5625 .- 2196-5420. ; 10:4, s. 964-976 Tidskriftsartikel (refereegranskat)abstract High-quality datasets are of paramount importance for the operation and planning of wind farms. However, the datasets collected by the supervisory control and data acquisition (SCADA) system may contain missing data due to various factors such as sensor failure and communication congestion. In this paper, a data-driven approach is proposed to fill the missing data of wind farms based on a context encoder (CE), which consists of an encoder, a decoder, and a discriminator. Through deep convolutional neural networks, the proposed method is able to automatically explore the complex nonlinear characteristics of the datasets that are difficult to be modeled explicitly. The proposed method can not only fully use the surrounding context information by the reconstructed loss, but also make filling data look real by the adversarial loss. In addition, the correlation among multiple missing attributes is taken into account by adjusting the format of input data. The simulation results show that CE performs better than traditional methods for the attributes of wind farms with hallmark characteristics such as large peaks, large valleys, and fast ramps. Moreover, the CE shows stronger generalization ability than traditional methods such as auto-encoder, K-means, k-nearest neighbor, back propagation neural network, cubic interpolation, and conditional generative adversarial network for different missing data scales.
13.	Liao, Wenlong, et al. (författare) Fault diagnosis of power transformers using graph convolutional network 2021 Ingår i: CSEE Journal of Power and Energy Systems. - : Power System Technology Press. - 2096-0042. ; 7:2, s. 241-249 Tidskriftsartikel (refereegranskat)abstract Existing methods for transformer fault diagnosis either train a classifier to fit the relationship between dissolved gas and fault type or find some similar cases with unknown samples by calculating the similarity metrics. Their accuracy is limited, since they are hard to learn from other algorithms to improve their own performance. To improve the accuracy of transformer fault diagnosis, a novel method for transformer fault diagnosis based on graph convolutional network (GCN) is proposed. The proposed method has the advantages of two kinds of existing methods. Specifically, the adjacency matrix of GCN is utilized to fully represent the similarity metrics between unknown samples and labeled samples. Furthermore, the graph convolutional layers with strong feature extraction ability are used as a classifier to find the complex nonlinear relationship between dissolved gas and fault type. The back propagation algorithm is used to complete the training process of GCN. The simulation results show that the performance of GCN is better than that of the existing methods such as convolutional neural network, multi-layer perceptron, support vector machine, extreme gradient boosting tree, k-nearest neighbors and Siamese network in different input features and data volumes, which can effectively meet the needs of diagnostic accuracy.
14.	Liao, Wenlong, et al. (författare) Scenario Generations for Renewable Energy Sources and Loads Based on Implicit Maximum Likelihood Estimations 2022 Ingår i: Journal of Modern Power Systems and Clean Energy. - : Journal of Modern Power Systems and Clean Energy. - 2196-5625 .- 2196-5420. ; 10:6, s. 1563-1575 Tidskriftsartikel (refereegranskat)abstract Scenario generations for renewable energy sources and loads play an important role in the stable operation and risk assessment of integrated energy systems. This paper proposes a deep generative network based method to model time-series curves, e.g., power generation curves and load curves, of renewable energy sources and loads based on implicit maximum likelihood estimations (IMLEs), which can generate realistic scenarios with similar patterns as real ones. After training the model, any number of new scenarios can be obtained by simply inputting Gaussian noises into the data generator of IMLEs. The proposed approach does not require any model assumptions or prior knowledge of the form in the likelihood function being made during the training process, which leads to stronger applicability than explicit density model based methods. The extensive experiments show that the IMLEs accurately capture the complex shapes, frequency-domain characteristics, probability distributions, and correlations of renewable energy sources and loads. Moreover, the proposed approach can be easily generalized to scenario generation tasks of various renewable energy sources and loads by fine-tuning parameters and structures.
15.	Liao, Wenlong, et al. (författare) Simple Data Augmentation Tricks for Boosting Performance on Electricity Theft Detection Tasks 2023 Ingår i: IEEE transactions on industry applications. - : Institute of Electrical and Electronics Engineers (IEEE). - 0093-9994 .- 1939-9367. ; 59:4, s. 1-12 Tidskriftsartikel (refereegranskat)abstract In practical engineering, electricity theft detection is usually performed on highly imbalanced datasets (i.e., the number of fraudulent samples is much smaller than the benign ones), which limits the accuracy of the classifier. To alleviate the data imbalance problem, this article proposes simple data augmentation tricks (SDAT) to boost performance on electricity theft detection tasks. SDAT includes five simple but powerful operations: adding noises to electricity consumption readings, drifting values of electricity consumption readings, quantizing electricity consumption readings to a level set, adding a fixed value to electricity consumption readings, and adding changeable values to electricity consumption readings. In addition, eight potential tricks are also mentioned. Numerical simulations are conducted on a real-world dataset. The simulation results show that SDAT can significantly boost the performance of different classifiers, especially for small datasets. Besides, specific suggestions on how to select parameters of SDAT are provided for its migration use to other datasets.
16.	Tian, Wenlong, et al. (författare) mu J-level multi-cycle terahertz generation in a periodically poled Rb:KTP crystal 2021 Ingår i: Optics Letters. - : The Optical Society. - 0146-9592 .- 1539-4794. ; 46:4, s. 741-744 Tidskriftsartikel (refereegranskat)abstract We demonstrate multi-cycle terahertz (MC-THz) generation in a 15.5 mm long periodically poled rubidium (Rb)-doped potassium titanyl phosphate (Rb:PPKTP) crystal with a poling period of 300 mu m. By cryogenically cooling the crystal to 77 K, up to 0.72 mu J terahertz energy is obtained at a frequency of 0.5 THz with a 3 GHz bandwidth. A maximum internal optical-to-terahertz conversion efficiency of 0.16% is achieved, which is comparable with results achieved using periodically poled lithium niobate crystal. Neither photorefractive effects nor damage was observed with up to 900 mJ/cm(2), showing the great potential of Rb:PPKTP for multi-millijoule-level MC-THz generation.
17.	Ticknor, Christopher, et al. (författare) Spectral and dynamical analysis of a single vortex ring in anisotropic harmonically trapped three-dimensional Bose-Einstein condensates 2018 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 98:3 Tidskriftsartikel (refereegranskat)abstract In the present work, motivated by numerous recent experimental developments we revisit the dynamics of a single vortex ring in anisotropic harmonic traps. At the theoretical level, we start from a general Lagrangian dynamically capturing the evolution of a vortex ring and not only consider its spectrum of linearized excitations, but also explore the full nonlinear dynamical evolution of the ring as a vortical filament. The theory predicts that the ring is stable for 1 <= lambda <= 2, where lambda = omega(z)/omega(r) is the ratio of the trapping frequencies along the z and r axes, i. e., for spherical to slightly oblate condensates. We compare this prediction with direct numerical simulations of the full three-dimensional Gross-Pitaevskii equation (GPE) capturing the linearization spectrum of the ring for different values of the chemical potential and as a function of the anisotropy parameter.. We identify this result as being only asymptotically valid as the chemical potential mu -> 8, revealing how the stability interval narrows and, in particular, its upper bound decreases for finite mu. Finally, we compare at the dynamical level the results of the GPE with the ones effectively capturing the ring dynamics, revealing the unstable evolution for different values of lambda, as well as the good agreement between the two.
18.	Wang, Longguang, et al. (författare) NTIRE 2023 Challenge on Stereo Image Super-Resolution : Methods and Results 2023 Ingår i: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops (CVPRW). - Vancover : Institute of Electrical and Electronics Engineers (IEEE). - 9798350302493 - 9798350302509 ; , s. 1346-1372 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract In this paper, we summarize the 2nd NTIRE challenge on stereo image super-resolution (SR) with a focus on new solutions and results. The task of the challenge is to super-resolve a low-resolution stereo image pair to a high-resolution one with a magnification factor of x4. Compared with single image SR, the major challenge of this challenge lies in how to exploit additional information in another viewpoint and how to maintain stereo consistency in the results. This challenge has 3 tracks, including one track on distortion (e.g., PSNR) and bicubic degradation, one track on perceptual quality (e.g., LPIPS) and bicubic degradation, as well as another track on real degradations. In total, 175, 93, and 103 participants were successfully registered for each track, respectively. In the test phase, 21, 17, and 12 teams successfully submitted results with PSNR (RGB) scores better than the baseline. This challenge establishes a new benchmark for stereo image SR.
19.	Wang, Wenlong, et al. (författare) Chaotic temperature and bond dependence of four-dimensional Gaussian spin glasses with partial thermal boundary conditions 2018 Ingår i: Physical review. E. - : American Physical Society. - 2470-0045 .- 2470-0053. ; 98:6 Tidskriftsartikel (refereegranskat)abstract Spin glasses have competing interactions and complex energy landscapes that are highly susceptible to perturbations, such as the temperature or the bonds. The thermal boundary condition technique is an effective and visual approach for characterizing chaos and has been successfully applied to three dimensions. In this paper, we tailor the technique to partial thermal boundary conditions, where the thermal boundary condition is applied in a subset (three out of four in this work) of the dimensions for better flexibility and efficiency for a broad range of disordered systems. We use this method to study both temperature chaos and bond chaos of the four-dimensional Edwards-Anderson model with Gaussian disorder to low temperatures. We compare the two forms of chaos, with chaos of three dimensions, and also the four-dimensional +/- J model. We observe that the two forms of chaos are characterized by the same set of scaling exponents, bond chaos is much stronger than temperature chaos, and the exponents are also compatible with the +/- J model. Finally, we discuss the effects of chaos on the number of pure states in the thermal boundary condition ensemble.
20.	Wang, Wenlong, et al. (författare) Evidence of many thermodynamic states of the three-dimensional Ising spin glass 2020 Ingår i: Physical Review Research. - : American Physical Society. - 2643-1564. ; 2:4 Tidskriftsartikel (refereegranskat)abstract We present a large-scale simulation of the three-dimensional Ising spin glass with Gaussian disorder to low temperatures and large sizes using optimized population annealing Monte Carlo. Our primary focus is investigating the number of pure states regarding a controversial statistic, characterizing the fraction of centrally peaked disorder instances, of the overlap function order parameter. We observe that this statistic is subtly and sensitively influenced by the slight fluctuations of the integrated central weight of the disorder-averaged overlap function, making the asymptotic growth behavior very difficult to identify. Modified statistics effectively reducing this correlation are studied, and essentially monotonic growth trends are obtained. The effect of temperature is also studied, finding a larger growth rate at a higher temperature. Our state-of-the-art simulation and variance reduction data analysis suggest that the many pure states picture is most likely and coherent.
21.	Wang, Wenlong, et al. (författare) Fractal dimension of interfaces in Edwards-Anderson spin glasses for up to six space dimensions 2018 Ingår i: Physical review. E. - : American Physical Society. - 2470-0045 .- 2470-0053. ; 97:3 Tidskriftsartikel (refereegranskat)abstract The fractal dimension of domain walls produced by changing the boundary conditions from periodic to antiperiodic in one spatial direction is studied using both the strong-disorder renormalization group algorithm and the greedy algorithm for the Edwards-Anderson Ising spin-glass model for up to six space dimensions. We find that for five or fewer space dimensions, the fractal dimension is lower than the space dimension. This means that interfaces are not space filling, thus implying that replica symmetry breaking is absent in space dimensions fewer than six. However, the fractal dimension approaches the space dimension in six dimensions, indicating that replica symmetry breaking occurs above six dimensions. In two space dimensions, the strong-disorder renormalization group results for the fractal dimension are in good agreement with essentially exact numerical results, but the small difference is significant. We discuss the origin of this close agreement. For the greedy algorithm there is analytical expectation that the fractal dimension is equal to the space dimension in six dimensions and our numerical results are consistent with this expectation.
22.	Wang, Wenlong, et al. (författare) Melting of a two-dimensional monodisperse cluster crystal to a cluster liquid 2019 Ingår i: Physical review. E. - : American Physical Society. - 2470-0045 .- 2470-0053. ; 99:4 Tidskriftsartikel (refereegranskat)abstract Monodisperse ensembles of particles that have cluster crystalline phases at low temperatures can model a number of physical systems, such as vortices in type-1.5 superconductors, colloidal suspensions, and cold atoms. In this work, we study a two-dimensional cluster-forming particle system interacting via an ultrasoft potential. We present a simple mean-field characterization of the cluster-crystal ground state, corroborating with Monte Carlo simulations for a wide range of densities. The efficiency of several Monte Carlo algorithms is compared, and the challenges of thermal equilibrium sampling are identified. We demonstrate that the liquid to cluster-crystal phase transition is of first order and occurs in a single step, and the liquid phase is a cluster liquid.
23.	Wang, Wenlong, et al. (författare) Pinning effects in a two-dimensional cluster glass 2021 Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 104:14 Tidskriftsartikel (refereegranskat)abstract We study numerically the nonequilibrium glass formation and depinning transition of a system of two-dimensional cluster-forming monodisperse particles in the presence of pinning disorder. The pairwise interaction potential is nonmonotonic and is motivated by the intervortex forces in type-1.5 superconductors but also applies to a variety of other systems. Such systems can form cluster glasses due to the intervortex interactions following a thermal quench, without underlying disorder. We study the effects of vortex pinning in these systems. We find that a small density of pinning centers of moderate depth has a limited effect on vortex glass formation, i.e., formation of vortex glasses is dominated by intervortex interactions. At higher densities, pinning can significantly affect glass formation. The cluster glass depinning, under a constant driving force, is found to be plastic, with features distinct from non-cluster-forming systems such as clusters merging and breaking. We find that, in general, vortices with cluster-forming interaction forces can exhibit stronger pinning effects than regular vortices.
24.	Wang, Wenlong, et al. (författare) Ring dark solitons in three-dimensional Bose-Einstein condensates 2019 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 100:5 Tidskriftsartikel (refereegranskat)abstract In this work we present a systematic study of the three-dimensional extension of the ring dark soliton, examining its existence, stability, and dynamics in isotropic harmonically trapped Bose-Einstein condensates. Detuning the chemical potential from the linear limit, the ring dark soliton becomes unstable immediately but can be fully stabilized by an external cylindrical potential. The ring has a large number of unstable modes which are analyzed through spectral stability analysis. Furthermore, a few typical destabilization dynamical scenarios are revealed with a number of interesting vortical structures emerging, such as the two or four coaxial parallel vortex rings. In the process of considering the stability of the structure, we also develop a modified version of the degenerate perturbation theory method for characterizing the spectra of the coherent structure. This semianalytical method can be reliably applied to any soliton with a linear limit to explore its spectral properties near this limit. The good agreement of the resulting spectrum is illustrated via a comparison with the full numerical Bogolyubov-de Gennes spectrum. The application of the method to the two-component ring dark-bright soliton is also discussed.
25.	Wang, Wenlong, et al. (författare) Solving the one-dimensional Ising chain via mathematical induction : an intuitive approach to the transfer matrix 2019 Ingår i: European journal of physics. - : IOP PUBLISHING LTD. - 0143-0807 .- 1361-6404. ; 40:6 Tidskriftsartikel (refereegranskat)abstract The aim of this work is to present a formulation to solve the one-dimensional Ising model using the elementary technique of mathematical induction. This formulation is physically clear and leads to the same partition function form as the transfer matrix method, which is a common subject in the introductory courses of statistical mechanics. In this way our formulation is a useful tool to complement the traditional more abstract transfer matrix method. The method can be straightforwardly generalised to other short-range chains, coupled chains and is also computationally friendly. These two approaches provide a more complete understanding of the system, and therefore our work can be of broad interest for undergraduate teaching in statistical mechanics.
26.	Wang, Wenlong, et al. (författare) Three-dimensional universality class of the Ising model with power-law correlated critical disorder 2019 Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 100:14 Tidskriftsartikel (refereegranskat)abstract We use large-scale Monte Carlo simulations to test the Weinrib-Halperin criterion that predicts new universality classes in the presence of sufficiently slowly decaying power-law correlated quenched disorder. While new universality classes are reasonably well established, the predicted exponents are controversial. We propose a method of growing such correlated disorder using the three-dimensional Ising model as a benchmark system for both generating disorder and studying the resulting phase transition. Critical equilibrium configurations of a disorder-free system are used to define the two-value distributed random bonds with a small power-law exponent given by the pure Ising exponent. Finite-size scaling analysis shows a new universality class with a single phase transition, but the critical exponents nu(d) = 1.13(5), eta(d) = 0.48(3) differ significantly from theoretical predictions. We find that depending on the details of the disorder generation, disorder-averaged quantities can develop peaks at two temperatures for finite sizes. Finally, a layer model with the two values of bonds spatially separated in halves of the system genuinely has multiple phase transitions, and thermodynamic properties can be flexibly tuned by adjusting the model parameters.
27.	Wang, Yan Feng, et al. (författare) Experimental study on immersion phase change cooling of lithium-ion batteries based on R1233ZD(E)/ethanol mixed refrigerant 2023 Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 220 Tidskriftsartikel (refereegranskat)abstract To improve heat dissipation and temperature uniformity for the lithium-ion battery module of electric vehicle, the immersion phase change cooling characteristics of R1233ZD(E)/Ethanol mixed refrigerant were studied experimentally in a staggered battery module, which is composed of 50 batteries. At 101.3 kPa saturated vapor pressure, coupled wall boiling and forced convection heat transfer was analyzed under different discharge rates (1 C, 2 C, and 3 C), filling volume fractions of R1233ZD(E) (0.463, 0.540, 0.630, 0.735, and 0.857), and inlet volume flow rates (652.0, 1086.0, 1521.0, and 2172.0 mL min- 1). Meanwhile, the outlet vapor quality of the two-phase flow was calculated according to energy conservation. The results show that the heat generation of the battery was dominated by the operating current. With the decrease of the output power of the battery, the heat generation first increases rapidly, then increases gently, and finally decreases sharply. When low boiling point R1233ZD(E) was mixed into ethanol, wall boiling heat transfer was effectively enhanced, and the temperature uniformity of the battery module could be improved by up to 57.0\%. However, the outlet vapor quality of the two-phase flow showed that when the volume fraction of R1233ZD(E) exceeded 0.803, wall boiling departed from the nucleate boiling regime as well as heat transfer and temperature quantities changed accordingly. Forced convection heat transfer of liquid-phase played a leading role in reducing the temperature rise of the battery module, and its contribution increased with the increase of refrigerant inlet flow rate. When the inlet flow rate increased from 652.0 mL min- 1 to 1086.0 mL min- 1, the module temperature rise decreased by 14.8%. Nevertheless, forced convection of liquid-phase weakened battery wall boiling, which adversely affected the temperature uniformity of the battery module.
28.	Wang, Yusen, et al. (författare) Gated Recurrent Unit Network-Based Short-Term Photovoltaic Forecasting 2018 Ingår i: Energies. - : MDPI. - 1996-1073. ; 11:8 Tidskriftsartikel (refereegranskat)abstract Photovoltaic power has great volatility and intermittency due to environmental factors. Forecasting photovoltaic power is of great significance to ensure the safe and economical operation of distribution network. This paper proposes a novel approach to forecast short-term photovoltaic power based on a gated recurrent unit (GRU) network. Firstly, the Pearson coefficient is used to extract the main features that affect photovoltaic power output at the next moment, and qualitatively analyze the relationship between the historical photovoltaic power and the future photovoltaic power output. Secondly, the K-means method is utilized to divide training sets into several groups based on the similarities of each feature, and then GRU network training is applied to each group. The output of each GRU network is averaged to obtain the photovoltaic power output at the next moment. The case study shows that the proposed approach can effectively consider the influence of features and historical photovoltaic power on the future photovoltaic power output, and has higher accuracy than the traditional methods.
29.	Yang, Dechang, et al. (författare) Data-Driven Optimization Control for Dynamic Reconfiguration of Distribution Network 2018 Ingår i: Energies. - : MDPI. - 1996-1073. ; 11:10 Tidskriftsartikel (refereegranskat)abstract To improve the reliability and reduce power loss of distribution network, the dynamic reconfiguration is widely used. It is employed to find an optimal topology for each time interval while satisfying all the physical constraints. Dynamic reconfiguration is a non-deterministic polynomial problem, which is difficult to find the optimal control strategy in a short time. The conventional methods solved complex model of dynamic reconfiguration in different ways, but only local optimal solutions can be found. In this paper, a data-driven optimization control for dynamic reconfiguration of distribution network is proposed. Through two stages that include rough matching and fine matching, the historical cases which are similar to current case are chosen as candidate cases. The optimal control strategy suitable for the current case is selected according to dynamic time warping (DTW) distances which evaluate the similarity between the candidate cases and the current case. The advantage of the proposed approach is that it does not need to solve complex model of dynamic reconfiguration, and only uses historical data to obtain the optimal control strategy for the current case. The cases study shows that the optimization results and the computation time of the proposed approach are superior to conventional methods.
30.	Yang, Hao, et al. (författare) Intramolecular hydroxyl nucleophilic attack pathway by a polymeric water oxidation catalyst with single cobalt sites 2022 Ingår i: Nature Catalysis. - : Springer Nature. - 2520-1158. ; 5:5, s. 414-429 Tidskriftsartikel (refereegranskat)abstract Exploration of efficient water oxidation catalysts (WOCs) is the primary challenge in conversion of renewable energy into fuels. Here we report a molecularly well-defined heterogeneous WOC with Aza-fused, pi-conjugated, microporous polymer (Aza-CMP) coordinated single cobalt sites (Aza-CMP-Co). The single cobalt sites in Aza-CMP-Co exhibited superior activity under alkaline and near-neutral conditions. Moreover, the molecular nature of the isolated catalytic sites makes Aza-CMP-Co a reliable model for studying the heterogeneous water oxidation mechanism. By a combination of experimental and theoretical results, a pH-dependent nucleophilic attack pathway for O-O bond formation was proposed. Under alkaline conditions, the intramolecular hydroxyl nucleophilic attack (IHNA) process with which the adjacent -OH group nucleophilically attacks Co4+=O was identified as the rate-determining step. This process leads to lower activation energy and accelerated kinetics than those of the intermolecular water nucleophilic attack (WNA) pathway. This study provides significant insights into the crucial function of electrolyte pH in water oxidation catalysis and enhancement of water oxidation activity by regulation of the IHNA pathway.
31.	Zhang, Xiaorong, et al. (författare) Review of chemical looping process for carbonaceous feedstock Conversion : Rational design of oxygen carriers 2022 Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 325 Forskningsöversikt (refereegranskat)abstract The chemical looping partial oxidation (CLPO) process as a technology of chemical looping process (CLP) is recognized as a potential strategy for the efficient and clean conversion of fuels into syngas/H2. Herein, in view of the importance of low-cost high-performance metal oxides as oxygen carriers (OCs) for this conversion, we systematically review the classification and CLPO applications of such OCs and discuss the improvement of OC reactivity and stability via the creation of metal–metal or metal–support synergism, the generation of oxygen vacancies, and the enhancement of deactivation resistance. Further, we present the results of theoretical and experimental characterizations probing ion diffusion and surface reactions to provide insights into the related reaction mechanisms and touch on the challenges and opportunities of developing metal oxides with excellent reactivity and long-term cycling stability in CLP. Thus, this review facilitates the design and performance regulation of OCs for future energy conversion systems.
32.	Zhao, Li-Chen, et al. (författare) Spin soliton with a negative-positive mass transition 2020 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 101:4 Tidskriftsartikel (refereegranskat)abstract We obtain a striking spin soliton in a two-component Bose-Einstein condensate and investigate its motions in the presence of a constant force. The initially static spin soliton first moves in a direction opposite to the force and then changes direction, showing an extraordinary ac oscillation. The underlying mechanism is uncovered: the spin soliton can exhibit a periodic transition between negative and positive inertial mass because of a particular relation between its energy and moving velocity. We then develop a quasiparticle model that can account for this extraordinary oscillation. Important implications and possible applications are discussed.
33.	Zhu, Ruijin, et al. (författare) Short-term prediction for wind power based on temporal convolutional network 2020 Ingår i: Energy Reports. - : Elsevier BV. - 2352-4847. ; 6, s. 424-429 Tidskriftsartikel (refereegranskat)abstract The fluctuation and intermittence of wind power bring great challenges to the operation and control of the distribution network. Accurate short-term prediction for wind power is helpful to avoid the risk caused by the uncertainties of wind powers. To improve the accuracy of short-term prediction for wind power, the temporal convolutional network (TCN) is proposed in this paper. The proposed method solves the problem of long-term dependencies and performance degradation of deep convolutional model in sequence prediction by dilated causal convolutions and residual connections. The simulation results show that the training process of TCN is very stable and it has strong generalization ability. Furthermore, TCN shows higher forecasting accuracy than existing predictors such as the support vector machine, multi-layer perceptron, long short-term memory network, and gated recurrent unit network.

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