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BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

Research in Astronomy and Astrophysics 2024年第5期24卷 169-184页

作者： zhong-Mu Li Cai-Yan Mao Institute of Astronomy and Information Dali UniversityDali 671003China

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(G_(BP)-G_(RP)) < 0.5 mag). It makes the CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess con

关键词： Galaxy stellar content-(Galaxy:)open clusters and associations general-stars fundamental parameters

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Recent Advances in Nickel Catalyzed Carbonylative Reactions via the Insertion of Carbon Monoxide

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Chinese Journal of Chemistry 2024年第2期42卷 177-189页

作者： Xinzhou Chen Gang Chen zhong Lian Department of Dermatology State Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan UniversityChengduSichuan 610041China

Carbonyl compounds have attracted considerable attention due to their extensive applications in drug ***,they are important synthetic intermediates for the construction of carbon-carbon and carbon-heteroatom ***-metal-catalyzed carbonylation via the insertion of co is one of the most efficient and straightforward strategies to access carbonyl ***,most of the transition-metal-catalyzed carbonylative reactions require expensive and toxic noble-metal ***,there is a growing demand for the exploration of nickel-catalyzed carbonylative reactions via the insertion of CO due to the earth abundance and low cost of *** with the well-established palladium-catalyzed carbonylative reactions,nickel-catalyzed analogous transformations have been relatively *** is primarily because CO strongly binds to nickel,often resulting in catalyst *** recent years,some research groups have focused on using CO surrogates or NN_(2) pincer nickel catalyst to circumvent the formation of Ni(CO)_(4).Nickel-catalyzed carbonylation has been applied in the construction of carbonyl-containing compounds,such as ketones,carboxylic acids,thioesters,acyl chloride and carboxamides.

关键词： Carbonylation Nickel catalysis Carbon monoxide C1 chemistry Carbonyl-containing compounds

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Underwater Pulse Waveform Recognition Based on Hash Aggregate Discriminant Network

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Journal of Ocean University of China 2024年第3期23卷 654-660页

作者： WANG Fangchen zhong Guoqiang WANG Liang College of Computer Science and Technology Ocean University of ChinaQingdao 266100China College of Marine Technology Ocean University of ChinaQingdao 266100China

Underwater pulse waveform recognition is an important method for underwater object *** existing works focus on the application of traditional pattern recognition methods,which ignore the time-and space-varying characteristics in sound propagation channels and cannot easily extract valuable waveform *** propagation channels in seawater are time-and space-varying convolutional *** the extraction of the waveform features of underwater acoustic signals,the effect of high-accuracy underwater acoustic signal recognition is identified by eliminating the influence of time-and space-varying convolutional channels to the greatest extent *** propose a hash aggregate discriminative network(HADN),which combines hash learning and deep learning to minimize the time-and space-varying effects on convolutional channels and adaptively learns effective underwater waveform features to achieve high-accuracy underwater pulse waveform *** the extraction of the hash features of acoustic signals,a discrete constraint between clusters within a hash feature class is *** constraint can ensure that the influence of convolutional channels on hash features is *** addition,we design a new loss function called aggregate discriminative loss(AD-loss).The use of AD-loss and softmax-loss can increase the discriminativeness of the learned hash *** results show that on pool and ocean datasets,which were collected in pools and oceans,respectively,by using acoustic collectors,the proposed HADN performs better than other comparative models in terms of accuracy and mAP.

关键词： convolutional channel hash aggregate discriminative network aggregate discriminant loss waveform recognition

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Design and simulation investigations on charge transport layers‑free in lead‑free three absorber layer all‑perovskite solar cells

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Frontiers of Optoelectronics 2024年第2期17卷 69-85页

作者： Guangdong Li Mingxiang Xu zhong Chen School of Physics Southeast UniversityNanjing 211189China

The multiple absorber layer perovskite solar cells(PSCs)with charge transport layers-free(CTLs-free)have drawn widespread research interest due to their simplified architecture and promising photoelectric *** the circumstances,the novel design of CTLs-free inversion PSCs with stable and nontoxic three absorber layers(triple Cs_(3)Bi_(2)I_(9),single MASnI_(3),double Cs_(2)TiBr_(6))as optical-harvester has been numerically simulated by utilizing wxAMPS simulation software and achieved high power conversion efficiency(PCE)of 14.8834%.This is owing to the innovative architecture of PSCs favors efficient transport and extraction of more holes and the slender band gap MASnI_(3)extends the absorption spectrum to the near-infrared periphery compared with the two absorber layers architecture of ***,the performance of the device with p-type-Cs_(3)Bi_(2)I_(9)/p-type-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture is superior to the one with the p-type-Cs_(3)Bi_(2)I_(9)/ntype-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture due to less carrier recombination and higher carrier life time inside the absorber *** simulation results reveal that Cs_(2)TiF_(6)double perovskite material stands out as the best ***,an excellent PCE of 21.4530%can be obtained with the thicker MASnI_(3)absorber layer thickness(0.4μm).Lastly,the highestperformance photovoltaic devices(28.6193%)can be created with the optimized perovskite doping density of around E15 cm^(3)(Cs_(3)Bi_(2)I_(9)),E18 cm^(3)(MASnI_(3)),and 1.5E19 cm^(3)(Cs_(2)TiBr_(6)).This work manifests that the proposed CTLs-free PSCs with multi-absorber layers shall be a relevant reference for forward applications in electro-optical and optoelectronic devices.

关键词： Multiple absorber layer PSCs CTLS-free·Inverted Narrow-band gap Simulation

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Reliability Assessment of a New General Matching Composed Network

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China Communications 2024年第2期21卷 245-257页

作者： Zhengyuan Liang Junbin Liang Guoxuan zhong Guangxi Key Laboratory of Multimedia Communications and Network Technology School of ComputerElectronics and InformationGuangxi UniversityNanning 530004China Jiangxi Engineering Laboratory of IoT Technologies for Crop Growth Ji’an 343000China

The reliability of a network is an important indicator for maintaining communication and ensuring its stable operation. Therefore, the assessment of reliability in underlying interconnection networks has become an increasingly important research issue. However, at present, the reliability assessment of many interconnected networks is not yet accurate,which inevitably weakens their fault tolerance and diagnostic capabilities. To improve network reliability,researchers have proposed various methods and strategies for precise assessment. This paper introduces a novel family of interconnection networks called general matching composed networks(gMCNs), which is based on the common characteristics of network topology structure. After analyzing the topological properties of gMCNs, we establish a relationship between super connectivity and conditional diagnosability of gMCNs. Furthermore, we assess the reliability of g MCNs, and determine the conditional diagnosability of many interconnection networks.

关键词： conditional diagnosability interconnection networks network reliability super connectivity

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Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites

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Earth and Planetary Physics 2024年第2期8卷 382-390页

作者： Hui Wang ChengZhi Wang YunFang zhong Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is0 in the Southern Hemisphere.

关键词： polar electrojet interplanetary magnetic field Bx local time asymmetry hemispheric difference

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Study of 26 Galactic Open Clusters with Extended Main-sequence Turnoffs

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Research in Astronomy and Astrophysics 2024年第6期24卷 28-37页

作者： Yang-Yang Deng zhong-Mu Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Institute of Astronomy and Information Dali UniversityDali 671003China

Recent studies indicate that some Galactic open clusters(OCs)exhibit extended main-sequence turnoff(eMSTO)in their color–magnitude diagrams(CMDs).However,the number of Galactic OCs with eMSTO structures detected so far is limited,and the reasons for their formation are still *** work identifies 26 Galactic OCs with undiscovered eMSTOs and investigates the causes of these *** population types and fundamental parameters of cluster samples are acquired using CMD fitting *** them,the results of 11 OCs are reliable as the observed CMDs are *** propose the crucial role of stellar binarity and confirm the importance of stellar rotation in reproducing eMSTO *** results also show that the impact of age spread is important,as it can adequately explain the structure of young OCs and fit the observed CMDs of intermediate-age OCs better.

关键词： (stars:)binaries:general Galaxy:fundamental parameters (Galaxy:)open clusters and associations:general (stars:)Hertzsprung Russell and C-M-diagrams

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A Joint Activity and Data Detection Scheme for Asynchronous Grant-Free Rateless Multiple Access

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China Communications 2024年第1期21卷 34-52页

作者： Wei Zhang Xiaofeng zhong Shidong Zhou Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

This paper considers the frameasynchronous grant-free rateless multiple access(FAGF-RMA)scenario,where users can initiate access at any symbol time,using shared channel resources to transmit data to the base *** coding is introduced to enhance the reliability of the *** literature has shown that FA-GFRMA can achieve lower access delay than framesynchronous grant-free rateless multiple access(FSGF-RMA),with extreme reliability enabled by rateless *** support FA-GF-RMA in more practical scenarios,a joint activity and data detection(JADD)scheme is *** the feature of sporadic traffic,approximate message passing(AMP)is exploited for transmission signal matrix ***,to determine the packet start points,a maximum posterior probability(MAP)estimation problem is solved based on the recovered transmitted signals,leveraging the intrinsic power pattern in the *** iterative power-pattern-aided AMP algorithm is devised to enhance the estimation performance of *** results verify that the proposed solution achieves a delay performance that is comparable to the performance limit of FA-GF-RMA.

关键词： asynchronous grant-free JADD rateless codes

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Superior comprehensive properties of LaFe_(11.8)Si_(1.2)/Ce_(60)Co_(40) magnetocaloric composites

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Journal of Rare Earths 2024年第6期42卷 1073-1086,I0003页

作者： Xichun zhong Yuanxin Li Yucai Wu Jiaohong Huang Cuilan Liu Jian Liu zhongwu Liu Minglong zhong Zhenchen zhong R.V.Ramanujan School of Materials Science and Engineering South China University of TechnologyGuangzhou510640China Baotou Research Institute of Rare Earths Baotou014030China Center for Advanced Solidification Technology School of Materials Science and EngineeringShanghai UniversityShanghai200444China Jiangxi KeyLaboratory for Rare Earth Magnetic Materials and Devices&Institute for Rare Earth Magnetic Materials and Devices(IREMMD) Jiangxi University of Science and TechnologyGanzhou341000China School of Materials Science and Engineering Nanyang Technological University639798Singapore Singapore-HUJ Alliance for Research and Enterprise(SHARE) The Smart Grippers for Soft Robotics(SGSR)ProgrammeCampus for Research Excellence and Technological Enterprise(CREATE)138602Singapor

LaFe_(11.8)Si_(1.2)/10 wt%Ce_(60)Co_(40) composites were prepared by spark plasma sintering and subsequent diffusion annealing.A novel core-shell structure is observed with the LaFe11.8Si1.2 particles as the core and the(La,Ce)_(2)(Fe,Co,Si)_(17)(2:17)phase as the *** diffusion annealing time(t_(a))increases,this core-shell structure is replaced by the formation of the(La,Ce)_(1)(Fe,Co,Si)_(13) *** at 1323 K for 12 h results in samples with(-ΔSM)^(max) of 9.30 J/(kg·K)(Δμ0H=2 T),good mechanical properties((σbc)^(max)=402 MPa,ε=4.21%)and thermal conductivity of 8.7 W/(m·K).Thus,bulk composites with excellent comprehensive properties for magnetic refrigeration are obtained in this work.

关键词： LaFe_(11.8)Si_(1.2)/Ce_(60)Co_(40)composites Spark plasma sintering Diffusion annealing Microstructure evolution Magnetocaloric effect Rareearths

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Supercritical CO_(2) Cycles for Nuclear-Powered Marine Propulsion:Preliminary Conceptual Design and Off-Design Performance Assessment

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Journal of Thermal Science 2024年第1期33卷 328-347页

作者： LI Zhaozhi SHI Mingzhu SHAO Yingjuan zhong Wenqi Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China

Using the efficient,space-saving,and flexible supercritical carbon dioxide(sCO_(2)) Brayton cycle is a promising approach for improving the performance of nuclear-powered *** purpose of this paper is to design and compare sCO_(2) cycle power systems suitable for nuclear-powered *** the characteristics of nuclear-powered ships,this paper uses different indicators to comprehensively evaluate the efficiency,cost,volume,and partial load performance of several nuclear-powered sCO_(2) *** load-following strategies are also designed and *** results show that the partial cooling cycle is most suitable for nuclear-powered ships because it offers both high thermal efficiency and low volume and cost,and can maintain relatively high thermal efficiency at partial ***,the new load-following strategy that adjusts the turbine speed can keep the compressor away from the surge line,making the cycle more flexible and efficient compared to traditional inventory and turbine bypass strategies.

关键词： supercritical CO_(2)cycle nuclear marine propulsion off-design performance

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