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Distributed Secondary Control Based on Dynamic Diffusion Algorithm for Current Sharing and Average Voltage Regulation in DC Microgrids

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journal of Modern Power Systems and Clean Energy 2024年第2期12卷 597-607页

作者： Dawei Liao Fei Gao Daniel j.Rogers Wentao Huang dong Liu Houjun Tang Department of Electrical Engineering Shanghai Jiao Tong UniversityShanghaiChina Department of Engineering Science University of OxfordOxford OX12JDU.K. IEEE

This paper introduces a distributed secondary control scheme for achieving current sharing and average voltage regulation objectives in a DC *** proposed scheme employs a dynamic diffusion algorithm(DDA)instead of the consensus algorithm to enable distributed communication among *** help understand DDA,the relation of DDA and other diffusion algorithms is discussed in detail and its superiority is shown by comparison with diffusion and consensus ***,considering the discrete nature and different sampling time of the digital controller and communication network,a z-domain model of the entire DC microgrid is *** influence of communication and secondary control parameters on the system stability is *** on the established model,the tolerable communication rates are ***-time simulations conducted on the OPAL-RT platform validate the effectiveness of the proposed scheme,showcasing its advantages in terms of convergence speed and stability.

关键词： Cooperative control DC microgrid diffusion algorithm discrete-time modeling distributed secondary control

Coordinate-wise monotonic transformations enable privacy-preserving age estimation with 3D face point cloud

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Science China(Life Sciences) 2024年第7期67卷 1489-1501页

作者： Xinyu Yang Runhan Li Xindi Yang Yong Zhou Yi Liu jing-dong j.Han School of Life Sciences Peking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Academy for Advanced Interdisciplinary StudiesCenter for Quantitative Biology(CQB)Peking UniversityBeijing 100871China Beijing Key Lab of Traffic Data Analysis and Mining School of Computer and Information TechnologyBeijing Jiaotong UniversityBeijing 100044China Clinical Research Institute Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China

The human face is a valuable biomarker of aging,but the collection and use of its image raise significant privacy *** we present an approach for facial data masking that preserves age-related features using coordinate-wise monotonic *** first develop a deep learning model that estimates age directly from non-registered face point clouds with high accuracy and *** show that the model learns a highly indistinguishable mapping using faces treated with coordinate-wise monotonic transformations,indicating that the relative positioning of facial information is a low-level biomarker of facial *** visual perception tests and computational3D face verification experiments,we demonstrate that transformed faces are significantly more difficult to perceive for human but not for machines,except when only the face shape information is *** study leads to a facial data protection guideline that has the potential to broaden public access to face datasets with minimized privacy risks.

关键词： face point cloud age estimation face verification privacy coordinate-wise monotonic transformation

Local search yields a PTAS for fixed-dimensional k-means problem with penalties

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journal of the Operations Research Society of China 2024年第2期12卷 351-362页

作者： Fan Yuan Da-Chuan Xu dong-Lei Du dong-Mei Zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China Faculty of Management University of New BrunswickFrederictonNB E3B 9Y2Canada School of Computer Science and Technology Shandong Jianzhu UniversityJinan 250101ShandongChina

We study a problem called the k-means problem with penalties(k-MPWP),which is a natural generalization of the typical k-means *** this problem,we have a set D of client points in R^(d),a set F of possible centers in R^(d),and a penalty cost Pj>O for each point j∈*** are also given an integer k which is the size of the center point *** want to find a center point set S■F with size k,choose a penalized subset of clients P■D,and assign every client in D\P to its open *** goal is to minimize the sum of the squared distances between every point in D\P to its assigned centre point and the sum of the penalty costs for all clients in *** using the multi-swap local search technique and under the fixed-dimensional Euclidean space setting,we present a polynomial-time approximation scheme(PTAS)for the k-MPWP.

关键词： Approximation algorithm k-means Local search Penalty

Numerical Investigations on the Resonance Errors of Multiscale Discontinuous Galerkin Methods for One-Dimensional Stationary Schrödinger Equation

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Communications on Applied Mathematics and Computation 2024年第1期6卷 311-324页

作者： Bo dong Wei Wang Department of Mathematics University of Massachusetts DartmouthNorth DartmouthMA02747USA Department of Mathematics and Statistics Florida International UniversityMiamiFL33199USA

In this paper,numerical experiments are carried out to investigate the impact of penalty parameters in the numerical traces on the resonance errors of high-order multiscale discontinuous Galerkin(DG)methods(dong et *** j Sci Comput 66:321–345,2016;dong and Wang in j Comput Appl Math 380:1–11,2020)for a one-dimensional stationary Schrödinger *** work showed that penalty parameters were required to be positive in error analysis,but the methods with zero penalty parameters worked fine in numerical simulations on coarse *** this work,by performing extensive numerical experiments,we discover that zero penalty parameters lead to resonance errors in the multiscale DG methods,and taking positive penalty parameters can effectively reduce resonance errors and make the matrix in the global linear system have better condition numbers.

关键词： Discontinuous Galerkin(DG)method Multiscale method Resonance errors One-dimensional Schrödinger equation

Machine learning ensemble model prediction of northward shift in potato cyst nematodes(Globodera rostochiensis and ***)distribution under climate change conditions

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journal of Integrative Agriculture 2024年第10期23卷 3576-3591页

作者： Yitong He Guanjin Wang Yonglin Ren Shan Gao dong Chu Simon j.McKirdy Shandong Engineering Research Centre for Environment-friendly Agricultural Pest Management College of Plant Health andMedicineQingdao Agricultural UniversityQingdao 266109China Harry Butler Institute Murdoch UniversityMurdochWA 6150Australia School of Information Technology Murdoch UniversityPerthWA 6150Australia Hebei Dahaituo National Nature Reserve Management Centre Chicheng 075500China

Potato cyst nematodes(PCNs)are a significant threat to potato production,having caused substantial damage in many *** the future distribution of PCN species is crucial to implementing effective biosecurity strategies,especially given the impact of climate change on pest species invasion and *** learning(ML),specifically ensemble models,has emerged as a powerful tool in predicting species distributions due to its ability to learn and make predictions based on complex data ***,this research utilised advanced machine learning techniques to predict the distribution of PCN species under climate change conditions,providing the initial element for invasion risk *** first used Global Climate Models to generate homogeneous climate predictors to mitigate the variation among ***,five machine learning models were employed to build two groups of ensembles,single-algorithm ensembles(ESA)and multi-algorithm ensembles(EMA),and compared their *** this research,the EMA did not always perform better than the ESA,and the ESA of Artificial Neural Network gave the highest performance while being *** results indicated that the distribution range of PCNs would shift northward with a decrease in tropical zones and an increase in northern ***,the total area of suitable regions will not change significantly,occupying 16-20%of the total land surface(18%under current conditions).This research alerts policymakers and practitioners to the risk of PCNs’incursion into new ***,this ML process offers the capability to track changes in the distribution of various species and provides scientifically grounded evidence for formulating long-term biosecurity plans for their control.

关键词： invasive species distribution future climates homogeneous climate predictors single-algorithm ensembles multi-algorithm ensembles artificial neural network

Poly(heptazine imide)nanocrystal for hydrogen peroxide evolution in the dark by accumulating photo-generated electrons

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Nano Research 2024年第9期17卷 8036-8044页

作者： Song Kou Shu lian Xiaodong Xie Wei Ren Yu jin jiahui Bao Honghui Ou Guidong Yang XjTU-Oxford International joint Laboratory for Catalysis School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’an 710049China Fujian-Taiwan-Hongkong-Macao Science and Technology Cooperation Base of Intelligent Pharmaceutics Institute of OceanographyCollege of Materials and Chemical EngineeringMinjiang UniversityFuzhou 350108China School of Food and Bioengineering Fujian Polytechnic Normal UniversityFuqing 350300China

Organic conjugated polymers have received extensive attention due to their unique electronic ***,there have been relatively few reports on the dark photocatalytic reactions utilizing organic conjugated ***,we report the successful synthesis of an organic conjugated polymer based on poly(heptazine imide)nanocrystals(CNNCs)for H_(2)O_(2)evolution and biomedical applications using a simple salt molten method and sonication-centrifugation *** results show that these colloid CNNCs have the characteristics of photogenerated electrons accumulation and realize dark photocatalysis with high reducibility under visible light ***,these accumulating photogenerated electrons can reduce O_(2)in darkness to produce H_(2)O_(2).In addition,cytotoxicity tests were conducted and it was found that H_(2)O_(2)produced under dark conditions could oxidize L-arginine(L-Arg)to NO,which effectively killed tumors in the *** work provides an important strategy to construct organic conjugated semiconductor nanocrystals and applying them to future energy and biomedical fields.

关键词： poly(heptazine imide) photocatalysis photogenerated electrons hydrogen peroxide evolution cancer treatment

Recent advancements in thermal conductivity of magnesium alloys

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journal of Magnesium and Alloys 2024年第5期12卷 1687-1708页

作者： Hao Lv jun Tan Qian Yuan Fanglei Wang Yunxuan Zhou Quan dong Aitao Tang jürgen Eckert Bin jiang Fusheng Pan National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 12Leoben A-8700Austria Erich Schmid Institute of Materials Science Austrian Academy of SciencesJahnstraße 12Leoben A-8700Austria

As highly integrated circuits continue to advance,accompanied by a growing demand for energy efficiency and weight reduction,materials are confronted with mounting challenges pertaining to thermal conductivity and lightweight *** virtue of numerous intrinsic mechanisms,as a result,the thermal conductivity and mechanical properties of the Mg alloys are often inversely related,which becomes a bottleneck limiting the application of Mg *** on several effective modification methods to improve the thermal conductivity of Mg alloys,this paper describes the law of how they affect the mechanical properties,and clearly indicates that peak aging treatment is one of the best ways to simultaneously enhance an alloy's thermal conductivity and mechanical *** the most frequently used Mg alloy,cast alloys exhibit substantial potential for achieving high thermal ***,recent reports indicate that hot deformation can significantly improve the mechanical properties while maintaining,and potentially slightly enhancing,the alloy's thermal *** presents a meaningful way to develop Mg alloys for applications in the field of small-volume heat dissipation components that require high *** comprehensive review begins by outlining standard testing and prediction methods,followed by the theoretical models used to predict thermal conductivity,and then explores the primary influencing factors affecting thermal *** review summarizes the current development status of Mg alloys,focusing on the quest for alloys that offer both high thermal conductivity and high *** concludes by providing insights into forthcoming prospects and challenges within this field.

关键词： Mg alloy Thermal conductivity Mechanical properties Solute atom Second phase

Effects of Aging at 550℃ on α'-Martensitic Transformation of High Si-Bearing Metastable Austenitic Stainless Steel Weld Metal

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1467-1479页

作者： Yakui Chen Shitong Wei dong Wu Shanping Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The high Si-bearing 15Cr-9Ni-Nb metastable austenitic stainless steel weld metal was prepared via gas tungsten arc welding and then processed by stabilized heat treatment(SHT)at 850℃ for 3 *** effects of 550℃ aging on the α'-martensitic transformation of the as-welded and the SHT weld metals were *** results showed that the weld metal had poor thermal stability of *** precipitation of NbC during the 850℃ SHT made the thermal stability of the local matrix decrease and led to the formation of a large amount of C-depleted α'-*** precipitation of coarse σ-phase at the δ-ferrite led to the Cr-depleted zone and the formation of Cr-depleted α'-martensite at the early stage of 550℃ *** homogenized diffusion of C and Cr in the matrix during 550℃ aging led to the restoration of austenitic thermal stability and the decrease of α'-martensite *** C-depleted α'-martensite content in the SHT weld metal decreased rapidly at the early stage of aging due to the fast diffusion rate of the C atom in the matrix,while the Cr-depleted α'-martensite decreased at the later stage of aging due to the decreased diffusion rate of the Cr.

关键词： Metastable austenitic stainless steel weld metal α'-martensitic transformation δ-ferrite σ-phase

Overlooked interaction between redox-mediator and bisphenol-A in permanganate oxidation

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Environmental Science and Ecotechnology 2024年第5期21卷 248-255页

作者： Honglong Zhang Qiaoqiao Zhao Kangbao Zhong Ruopeng Bai jiaojiao dong jun Ma jing Zhang Timothy j.Strathmann School of Environment Harbin Institute of TechnologyHarbin150090PR China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing100084PR China School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Chemical Theory and MechanismChongqing UniversityChongqing401331PR China College of Environment and Ecology Chongqing UniversityChongqing400045PR China Department of Civil and Environmental Engineering Colorado School of Mines1500 Illinois StreetGoldenCO80401United States

Research efforts on permanganate(Mn(VII))combined with redox-mediator(RM),have received increasing attention due to their significant performance for bisphenol-A(BPA)***,the mechanisms underpinning BPA degradation remain *** we show the overlooked interactions between RM and BPA during permanganate oxidation by introducing an RMdN-hydroxyphthalimide(NHPI).We discovered that the concurrent generation of MnO_(2) and phthalimide-N-oxyl(PINO)radical significantly enhances BPA oxidation within the pH range of *** detection of radical cross-coupling products between PINO radicals and BPA or its derivatives corroborates the pivotal role of radical cross-coupling in BPA ***,we observed the formation of an NHPI-BPA complex,which undergoes preferential oxidation by Mn(VII),marked by the emergence of an electronrich domain in *** findings unveil the underlying mechanisms in the Mn(VII)/RM system and bridge the knowledge gap concerning BPA transformation via *** research paves the way for further exploration into optimizing complexation sites and RM dosage,significantly enhancing the system's efficiency in water treatment applications.

关键词： Permanganate Redox-mediator Bisphenol-A Radical cross-coupling Complexation