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Mg/MgO interfaces as efficient hydrogen evolution cathodes causing accelerated corrosion of additive manufactured Mg alloys:A DFT analysis

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Journal of Magnesium and Alloys 2024年第1期12卷 110-119页

作者： Man-Fai Ng Kai Xiang Kuah Teck Leong tan Daniel John Blackwood Department of Materials Science&Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Republic of Singapore Institute of High Performance Computing(IHPC) Agency for ScienceTechnology and Research(A∗STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore

The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide *** Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes ***,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox *** determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic *** results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.

关键词： Magnesium Magnesium oxide Interface Hydrogen evolution DFT

Rethinking multi-spatial information for transferable adversarial attacks on speaker recognition systems

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 620-631页

作者： Junjian Zhang Hao tan Le Wang Yaguan Qian Zhaoquan Gu Guangzhou University GuangzhouChina Department of New Networks Peng Cheng LaboratoryShenzhenChina Harbin Institute of Technology(Shenzhen) ShenzhenChina Zhejiang University of Science and Technology HangzhouChina

Adversarial attacks have been posing significant security concerns to intelligent systems,such as speaker recognition systems(SRSs).Most attacks assume the neural networks in the systems are known beforehand,while black-box attacks are proposed without such information to meet practical *** black-box attacks improve trans-ferability by integrating multiple models or training on multiple datasets,but these methods are *** by the optimisation strategy with spatial information on the perturbed paths and samples,we propose a Dual Spatial Momentum Iterative Fast Gradient Sign Method(DS-MI-FGSM)to improve the transferability of black-box at-tacks against ***,DS-MI-FGSM only needs a single data and one model as the input;by extending to the data and model neighbouring spaces,it generates adver-sarial examples against the integrating *** reduce the risk of overfitting,DS-MI-FGSM also introduces gradient masking to improve *** authors conduct extensive experiments regarding the speaker recognition task,and the results demonstrate the effectiveness of their method,which can achieve up to 92%attack success rate on the victim model in black-box scenarios with only one known model.

关键词： speaker recognition spoofing attacks

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扰动线性多智能体系统的分布式资源分配算法

中国科学：信息科学 2024年第4期54卷 911-926页

作者：时侠圣孙长银穆朝絮安徽大学自主无人系统技术教育部工程研究中心合肥230601 安徽大学安徽省无人系统与智能技术工程研究中心合肥230601 安徽大学人工智能学院合肥230601 天津大学电气与自动化信息工程学院天津300192

针对一般异构线性多智能体系统的分布式资源分配问题,结合智能体动力学特性设计一类分布式优化算法,旨在实现扰动抑制的同时完成资源的最优分配.面对扰动模型已知干扰信号,本文利用智能体状态信息设计一种自适应分布式优化算法,其中拉... 详细信息

针对一般异构线性多智能体系统的分布式资源分配问题,结合智能体动力学特性设计一类分布式优化算法,旨在实现扰动抑制的同时完成资源的最优分配.面对扰动模型已知干扰信号,本文利用智能体状态信息设计一种自适应分布式优化算法,其中拉格朗日(Lagrange)乘子对偶变量控制参数自动增加,直至拉格朗日乘子对偶变量达到一致.当智能体状态信息不可测时,本文将上述算法修改为基于输出反馈的分布式优化算法.当全局成本函数强凸时,借助拉萨尔(LaSalle)不变性引理证明上述所提算法渐近收敛到全局最优解.面对未知扰动信号,本文利用扩张状态观测器技术设计一种分布式优化算法.当未知扰动信号为常数或其微分趋于零时,利用李雅普诺夫(Lyapunov)理论证明上述算法渐近收敛至全局最优解.最后利用数值仿真验证上述算法有效.

关键词：异构多智能体系统资源分配自适应通信权重状态反馈输出反馈未知扰动

Emergence of machine language: towards symbolic intelligence with neural networks

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National Science Review 2024年第4期11卷 27-30页

作者： Yuqi Wang Xu-Yao Zhang Cheng-Lin Liu Tieniu tan Zhaoxiang Zhang State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of Sciences

Representation learning is a core issue in artificial intelligence (AI). Currently,there exists a disparity in the choice of representation between humans and machines. Humans rely on discrete language for communicati...

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A Two-layer Framework for Mitigating the Con-gestion of Urban Power Grids Based on Flexible Topology with Dynamic Thermal Rating

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Protection and Control of Modern Power Systems 2024年第4期9卷 83-95页

作者： Yi Su Jiashen Teh Qian Luo Kangmiao tan Jiaying Yong the School of Automation and Electronic In-formation Xiangtan Universityxiangtan 411100China IEEE the School of Electrical and Electronic Engineering Universiti Sains Malaysia(USM)Penang 11800Malaysia the School of Computer Sciences Universiti Sains Malaysia(USM)Penang 11800Malaysia the Institute of Power Engineering College of EngineeringUniversiti Tenaga Nasional(UNITEN)Kajang 43000Malaysia

The urban power grid(UPG)combines transmission and distribution *** studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with safety margins and load *** situation is expected to worsen with the proliferation of renewable energy and electric *** this paper,a two-layer congestion mitigation framework is proposed,one which considers the congestion of the UPG with flexible *** the upper-layer,the particle swarm optimization algorithm is employed to optimize the power supply distribution(PSD)of substation *** is known as the upper-layer *** lower-layer model recalculates the new PSD,known as the lower-layer PSD,based on the topology candidates.A candidate topology is at an optimum when the Euclidean distance mismatch between the upper-and lower-layer PSDs is the *** optimum topology is tested by standard power flow to ascertain its *** optimum transitioning sequence between the initial and optimum topologies is also determined by the two-layer framework to minimize voltage deviation and line overloading of the UPG considering dynamic thermal *** proposed framework is tested on a 56-node test *** show that the proposed framework can significantly reduce congestion,maintain safety margins,and determine the optimum transitioning sequence.

关键词： Congestion mitigation urban power grid two-layer framework transitioning sequence dynamic thermal rating

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On B(5,20)2-Groups

Algebra Colloquium 2024年第3期31卷 429-440页

作者： E.A.Alhassan Y.L.tan Y.Li School of Mathematical Sciences Jiangsu UniversityZhenjiangJiangsu 212013China Department of Mathematics Brock UniversitySt.CatharinesOntario L2S 3A1Canada

A finite group G is said to be a B(n,k)group if for any n-element subset[a_(1),…,a_(n)]of G,|{a_(i)a_(j)|1≤i,j≤n}|≤*** is of interest to characterize the structure of B(n,k)groups for n(n+1)/2≤k≤n^(2)-*** B(5,k)groups for 15≤k≤19 have been investigated by several *** this paper,we give a complete characterization of B(5,20)2-groups by showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n,k)groups small squaring property central extension GAP

Numerical investigation of the photo-thermal characteristics of a direct absorption solar collector using Monte Carlo and finite volume methods

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Science China(Technological Sciences) 2024年第8期67卷 2436-2448页

作者： ZHU YanLong LI SuNing FAN JianHua KONG WeiQiang YUAN Yuan tan HePing School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Civil Engineering and Mechanical Engineering Technical University of DenmarkKoppels AlléBuilding 4042800 Kgs.LyngbyDenmark School of Vehicle and Energy Yanshan UniversityQinhuangdao 066004China

In this study, a novel model of photothermal conversion in a direct absorption solar collector based on the Monte Carlo and finite volume methods was built and validated and the temperatures of the novel and traditional solar collectors were compared. The sensitivity of the parameters to the radiative heat loss was investigated. Finally, the radiative heat transfer characteristics were discussed using the radiative exchange factor. The results of this study validated the advantages of the novel solar collector at both the surface and fluid temperatures. Under the conditions used in this study, the maximum temperature difference of the novel solar collector was 30 K, compared with 193 K for the traditional solar collector. Furthermore, the collector was divided into several units along the flow direction. The radiative exchange factor indicated that with an increase in the attenuation coefficient, the percentage of radiation intensity in the total solar radiation absorbed by the corresponding unit ***, it decreased with an increase in the incident angle and scattering albedo. These results provide a reference for addressing the low efficiency and thermal damage caused by traditional solar collectors at high temperatures.

关键词： direct absorption solar collector radiative heat transfer Monte Carlo

A Systematic Review of the Definition,Measurement,and Associated Factors of Pandemic Fatigue

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China CDC weekly 2024年第36期6卷 924-933,I0007页

作者： Ruohan Chen Qi tan Bowen Su Shuqi Wang Zhanwei Du WHO Collaborating Center for Infectious Disease Epidemiology and Control School of Public HealthLKS Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Laboratory of Data Discovery for Health Limited Hong Kong Science ParkHong Kong Special Administrative RegionChina Nanjing Tech University Nanjing CityJiangsu ProvinceChina School of Cybersecurity Northwestern Polytechnical UniversityXi’an CityShaanxi ProvinceChina.

The rapid emergence and widespread transmission of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)have prompted governments worldwide to enact policies and measures to manage the virus’s *** interventions have substantially contributed to controlling disease ***,they have also significantly disrupted daily life,leading to increased public fatigue and resistance to sustained control measures,a phenomenon known as pandemic *** develop a comprehensive understanding of pandemic fatigue,this review systematically explores the concept and identifies quantitative indicators for measuring *** reviewed studies on pandemic fatigue across various countries,summarized the contributing factors,and analyzed its impact on personal protective *** findings indicate that the enforcement of health measures significantly influences the onset of pandemic fatigue,while individual perceptions of risk can negatively affect personal protective behaviors,creating a feedback loop with increasing *** results underscore the importance of considering the current severity of the pandemic and individual decisionmaking processes in the implementation of *** our understanding of pandemic fatigue is essential for developing effective policy responses in preparation for future potential epidemics.

关键词： fatigue protective prompt

Compound events of heatwave and dust storm in the Taklamakan Desert

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Science China Earth Sciences 2024年第7期67卷 2073-2083页

作者： Yuzhi LIU Jianping HUANG Ziyuan tan Chenglong ZHOU Dan LI Yongkun XIE Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China Taklamakan National Station of Observation and Research for Desert Meteorology in Xinjiang Urumqi 830002China

Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global ***,the association between heatwaves and dust storms is poorly *** this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the *** results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),*** than 40% of heatwaves existed with dust events,which significantly lagged behind ***,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the *** high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD *** anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by *** climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.

关键词： Heatwave Dust storm Compound events Taklamakan Desert