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Variable projection algorithms with sparse constraint for separable nonlinear models

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Control Theory and Technology 2024年第1期22卷 135-146页

作者： hui-Lang xu Guang-Yong Chen Si-Qing cheng Min Gan Jing Chen College of Computer and Data Science Fuzhou UniversityFuzhou350116FujianChina Fujian Key Laboratory of Network Computing and Intelligent Information Processing Fuzhou UniversityFuzhou350116FujianChina Key Laboratory of Intelligent Metro of Universities in Fujian Fuzhou UniversityFuzhou350116FujianChina Engineering Research Center of Big Data Intelligence Ministry of EducationFuzhou UniversityFuzhou350116FujianChina School of Science Jiangnan UniversityWuxi214122JiangsuChina

Separable nonlinear models are widely used in various fields such as time series analysis, system modeling, and machine learning, due to their flexible structures and ability to capture nonlinear behavior of data. However, identifying the parameters of these models is challenging, especially when sparse models with better interpretability are desired by practitioners. Previous theoretical and practical studies have shown that variable projection (VP) is an efficient method for identifying separable nonlinear models, but these are based on \(L_2\) penalty of model parameters, which cannot be directly extended to deal with sparse constraint. Based on the exploration of the structural characteristics of separable models, this paper proposes gradient-based and trust-region-based variable projection algorithms, which mainly solve two key problems: how to eliminate linear parameters under sparse constraint;and how to deal with the coupling relationship between linear and nonlinear parameters in the model. Finally, numerical experiments on synthetic data and real time series data are conducted to verify the effectiveness of the proposed algorithms.

关键词： Variable projection(VP) Non-smooth constraint Separable nonlinear models

Improved mass relations of mirror nuclei

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Nuclear Science and Techniques 2024年第9期35卷 178-185页

作者： cheng xu Man Bao Department of Physics University of Shanghai for Science and TechnologyShanghai 200093China

In this study,we revisit the previous mass relations of mirror nuclei by considering 1/N-and 1/Z-dependent terms and the shell effect across a *** root-mean-squared deviation is 66 keV for 116 nuclei with neutron number N≥10,as com-pared with experimental data compiled in the AME2020 *** predicted mass excesses of 173 proton-rich nuclei,including 98 unknown nuclei,are tabulated in the Supplemental Material herein with competitive accuracy.

关键词： Nuclear mass Mirror nuclei Proton-rich nuclei

A synthesis of the Cretaceous wildfire record related to atmospheric oxygen levels?

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Journal of Palaeogeography 2024年第1期13卷 149-164页

作者： Da-Wei Lü Wen-xu Du Zhi-hui Zhang Yuan Gao Tian-Tian Wang Jin-cheng xu Ao-Cong Zhang cheng-Shan Wang Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals College of Earth Sciences and EngineeringShandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina School of Earth Sciences and Resources China University of GeosciencesBejing 100083China Institute of Earth Sciences China University of Geosciences(Bejing)Beijing 100083China

The Cretaceous was a significant greenhouse period in Earth's history with higher atmospheric CO_(2) levels and temperatures than today. Although evidence of combustion has been widely described from the Cretaceous deposits, our understanding of the spatiotemporal diversification pattern and process of the Cretaceous wildfires is still limited. In this study, we comprehensively synthesize a total of 271 published Cretaceous wildfire occurrences based on the by-products of burning, including fossil charcoal, pyrogenic inertinite(fossil charcoal in coal), and pyrogenic polycyclic aromatic hydrocarbons(PAHs). Spatially, the dataset shows a distinctive distribution of reported wildfire evidence characterized by high concentration in the middle latitudinal areas of the Northern Hemisphere(30°N-60°N) over the Cretaceous. Temporally, an overall increasing trend of the reported wildfire data from the Early Cretaceous to the Late Cretaceous is coincident with higher atmospheric O_(2) levels. However, the spatial and temporal patterns may result from many types of factors, such as taphonomy, preservation, and researcher biases, instead of a real picture of the Cretaceous wildfire evolution. To better understand the spatiotemporal diversification of the Cretaceous wildfire, more investigations on the record of wildfire occurrences during this period would be necessary in the future.

关键词： Wildfire Cretaceous Atmospheric oxygen Taphonomy Charcoal

Mold breakout prediction based on computer vision and machine learning

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Journal of Iron and Steel Research International 2024年第8期31卷 1947-1959页

作者： Yan-yu Wang Qi-can Wang Yong-chang Zhang Yong-hui cheng Man Yao xu-dong Wang School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina Key Laboratory of Solidification Control and Digital Preparation Technology Dalian University of TechnologyDalian 116024LiaoningChina

Breakout is the most serious production accident in continuous casting and must be detected and predicted by stable and reliable *** sticking region,which forms on the local copper plate and expanded into a"V"shape,is the typical precursor of ***,computer vision technology was exploited to visualize the temperature change rate of the copper plate based on the temperature signals from thermocouples;then,the static and dynamic features of the abnormal sticking region were ***,logistic regression and Adaboost models were used to study and identify these features,resulting in the development of a mold breakout prediction model based on computer vision and machine *** test results demonstrate that the proposed model can effectively distinguish anomalous temperature patterns and considerably reduce false alarms without any missing *** a result,the proposed method could offer valuable insights into the realm of abnormality detection and prediction during continuous casting process.

关键词： Abnormality detection Image processing Adaboost Logistic regression Continuous casting

Picomolar antimalarial agent from a Chinese medicinal plant

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Science China Chemistry 2022年第1期65卷 82-86页

作者： Bin Zhou Flavia M.Zimbres Joshua H.Butler cheng-hui xu Reagan S.Haney Yan Wu Maria B.Cassera Jian-Min Yue State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China Department of Biochemistry and Molecular Biology Center for Tropical and Emerging Global Diseases(CTEGD)University of GeorgiaAthensGeorgia 30602United States

In our long-term efforts searching for antimalarial agents from Chinese medicinal plants,seven novel dimeric sesquiterpenoids(1–7)with significant antimalarial activity were isolated and characterized from the whole plants of Sarcandra glabra *** by solid data acquired by diverse *** them,compound 3 with an EC50 value of 4.3 pM against the chloroquine-resistant Plasmodium falciparum is the most potent antimalarial agent reported hitherto,about 1,000-fold stronger than *** article further consolidates and refines our previously delineated structure-activity relationship for this antimalarial compound class.

关键词： medicinal plants dimeric sesquiterpenoids antimalarial agent structure-activity relationship

Single-wall carbon nanotube fiber non-woven fabrics with a high electrothermal heating response

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Nano Research 2024年第6期17卷 5621-5628页

作者： Xinyu Jiao Lele xu Xinyang Sun Chao Shi Peng-Xiang Hou Chang Liu hui-Ming cheng Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China Faculty of Materials Science and Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Carbon nanotube(CNT)fibers have great promise for constructing multifunctional fabrics with high electrical conductivity,good electro-heating ability,excellent flexibility,and a low ***,the inter-fiber contacts in the fabric greatly reduce these advantages and limit their ***,a simple pressure-fusing method to fabricate single-wall CNT(SWCNT)fiber non-woven fabrics(NWFs)that are composed of interconnected SWCNT fibers with fused joints is reported,which have good flexibility,a low density of 0.46 g/cm^(3),a high electrical conductivity of 3.7×10^(5)S/m,and a record high specific electrical conductivity of 803(S·m^(2))/*** also showed excellent electrical heating ability,so that a temperature of~160℃was rapidly reached at a low voltage of 2 *** with their low density,the SWCNT fiber NWFs are promising for use as a heating unit for low temperature battery protection and de-icing applications.

关键词： carbon nanotube fiber nonwoven fabrics fusing electrothermal heating

Effectiveness of Histopathological Examination of Ultrasound-guided Puncture Biopsy Samples for Diagnosis of Extrapulmonary Tuberculosis

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Biomedical and Environmental Sciences 2024年第2期37卷 170-177页

作者： GU Wen Fei SHI Xia MA Xin YU Jun Lei xu Jin Chuan QIAN cheng cheng HU Zhi Dong ZHANG hui Shanghai Public Health Clinical Center Fudan UniversityShanghai 201508China School of Laboratory Medicine and Life Science Wenzhou Medical UniversityWenzhou 325000ZhejiangChina Department of Laboratory Medicine Zhejiang Putuo HospitalZhoushan 316100ZhejiangChina Zhongshan Hospital Fudan UniversityShanghai 200032China

Objective To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis(EPTB).Methods This study was conducted at the Shanghai Public Health Clinical Center.A total of 115patients underwent ultrasound-guided puncture biopsy,followed by MGIT 960 culture(culture),smear,Gene Xpert MTB/RIF(Xpert),and histopathological *** assays were performed to evaluate their effectiveness in diagnosing EPTB in comparison to two different diagnostic criteria:liquid culture and composite reference standard(CRS).Results When CRS was used as the reference standard,the sensitivity and specificity of culture,smear,Xpert,and histopathological examination were(44.83%,89.29%),(51.72%,89.29%),(70.11%,96.43%),and(85.06%,82.14%),*** on liquid culture tests,the sensitivity and specificity of smear,Xpert,and pathological examination were(66.67%,72.60%),(83.33%,63.01%),and(92.86%,45.21%),*** examination showed the highest sensitivity but lowest ***,we found that the combination of Xpert and histopathological examination showed a sensitivity of 90.80%and a specificity of 89.29%.Conclusion Ultrasound-guided puncture sampling is safe and effective for the diagnosis of *** with culture,smear,and Xpert,histopathological examination showed higher sensitivity but lower *** combination of histopathology with Xpert showed the best performance characteristics.

关键词： Extrapulmonary tuberculosis Diagnosis Biopsy Histopathological examination Puncture samples

Precipitation evolution and properties of Cu-15Ni-8Sn alloys via Al microalloying during ageing

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Rare Metals 2024年第10期43卷 5216-5228页

作者： Wei Luo Li-Jun Peng xu-Jun Mi Hao-Feng Xie Yi-cheng Cao Shu-hui Huang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd. GRIMAT Engineering Institute Co. Ltd. General Research Institute for Nonferrous Metals School of Materials Science and Engineering South China University of Technology

Studies have shown that microalloying Cu-Ni-Sn alloys using Al inhibits discontinuous precipitation reactions;however,the mechanism has not been investigated ***,this study explored the properties and precipitation evolution of Cu-15Ni-8Sn alloys without and with 1 wt%Al（Cu-15Ni-8Sn-1Al） during ageing at 500℃ through X-ray diffraction （XRD）,scanning electron microscopy and high-angle annular dark-field scanning transmission electron *** results revealed that in Cu-15Ni-8Sn alloy,DO22ordering first occurred after spinodal decomposition,subsequently transitioning to an L12ordering phase,during which the discontinuous precipitates gradually nucleated at the grain boundaries and formed *** alloy hardness increased sharply with ordering and then decreased rapidly after reaching its peak value,due to the dominance of the discontinuous precipitation ***,the DO22ordered phase did not appear during the ageing of Cu-15Ni-8Sn-1Al alloy,and a Ni3(Alx,Sn1-x) intermetallic compound with L12structure was formed,consuming Ni and Sn atoms,thereby significantly suppressing the discontinuous precipitation reaction and improving the stability during prolonged *** tensile strength （yield strength） of Cu-15Ni-8Sn and Cu-15Ni-8Sn-1Al alloys at peak hardness were 855 （755） and 936 MPa （892 MPa）,respectively,and their main strengthening mechanisms were solid solution strengthening and precipitation *** addition of 1 wt% Al effectively improved the precipitation strengthening effect of Cu-Ni-Sn alloys but severely decreased the ductility.

关键词： Al addition Cu-15Ni-8Sn Precipitation sequence Strengthening mechanism

Bioinspired 3D flexible devices and functional systems

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National Science Review 2024年第3期11卷 271-295页

作者： xu cheng Zhangming Shen Yihui Zhang Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Laboratory of Flexible Electronics Technology Tsinghua University

Flexible devices and functional systems with elaborated three-dimensional(3D) architectures can endow better mechanical/electrical performances, more design freedom, and unique functionalities, when compared to their two-dimensional(2D) counterparts. Such 3D flexible devices/systems are rapidly evolving in three primary directions, including the miniaturization, the increasingly merged physical/artificial intelligence and the enhanced adaptability and capabilities of heterogeneous *** challenges exist in this emerging research area, such as relatively poor controllability in the locomotion of soft robotic systems, mismatch of bioelectronic interfaces, and signal coupling in multi-parameter sensing. By virtue of long-time–optimized materials, structures and processes, natural organisms provide rich sources of inspiration to address these challenges, enabling the design and manufacture of many bioinspired 3D flexible devices/systems. In this Review, we focus on bioinspired 3D flexible devices and functional systems, and summarize their representative design concepts, manufacturing methods, principles of structure-function relationship and broad-ranging applications. Discussions on existing challenges, potential solutions and future opportunities are also provided to usher in further research efforts toward realizing bioinspired 3D flexible devices/systems with precisely programmed shapes,enhanced mechanical/electrical performances, and high-level physical/artificial intelligence.

关键词： bioinspired designs biomimetic 3D structures 3D flexible electronics 3D functional systems direct 3D manufacture 2D-to-3D assembly