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基于变系数多因子半参数分布的高维动态高阶矩投资组合研究

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中国管理科学 2023年第12期31卷 272-280页

作者：黄光麟鲁万波西南财经大学统计学院四川成都611130 西南财经大学管理科学与工程学院四川成都611130

高维动态高阶矩投资组合的应用目前面临着“维数灾难”与“模型误设”两大难题。本文结合变系数多因子模型与时变半参数分布提出了一种基于半参数因子模型的动态协高阶矩建模方法,给出了模型设定、模型估计和模型检验方法。通过多因子... 详细信息

高维动态高阶矩投资组合的应用目前面临着“维数灾难”与“模型误设”两大难题。本文结合变系数多因子模型与时变半参数分布提出了一种基于半参数因子模型的动态协高阶矩建模方法,给出了模型设定、模型估计和模型检验方法。通过多因子模型有效缓解了动态协高阶矩估计存在的“维数灾难”问题,同时引入时变半参数结构有效解决了“模型误设”问题。实证结果表明:相较于现有的投资组合模型,基于半参数因子模型的动态高阶矩投资组合能够产生更高且更稳定的经济价值,同时更加契合金融资产收益率的时变特征,能够有效为金融市场参与者提供风险管理技术和科学决策依据。

关键词：多因子模型半参数结构时变协高阶矩建模动态投资组合

Photoacoustic/ultrasound dual-modal imaging of human nails: A pilot study

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Journal of Innovative Optical Health Sciences 2024年第6期17卷 15-28页

作者： Yanting Wen Yijie huang lin huang Dan Wu Renbin Zhong Shixie Jiang Yudi Zhang Ting Liu Xiaotian Liu Huabei Jiang Department of Ultrasound Chengdu Fifth People's Hospital Chengdu 611137P.R.China School of Computer Science and Technology Chongqing University of Posts and Telecommunications Chongqing 400065 P.R.China School of Electronic Science and Engineering University of Electronic Science and Technology Chengdu 611731 P.R.China Department of Psychiatry University of Florida College of Medicine GainesvilleFL 32610USA Department of Medical Engineering University of South Florida Tampa 33620USA

Traditional diagnostic techniques including visual examination,ultrasound(US),and magnetic resonance imaging(MRI)have limitations of in-depth information for the detection of nail disorders,resolution,and *** pilot study,for thefirst time,evaluates a dualmodality imaging system that combines photoacoustic tomography(PAT)with the US for the multiparametric quantitative assessment of human *** study involved a small cohort offive healthy volunteers who underwent PAT/US imaging for acquiring the nail unit *** PAT/US dual-modality imaging successfully revealed thefine anatomical structures and microvascular distribution within the nail and nail ***,this system utilized multispectral PAT to analyze functional tissue parameters,including oxygenated hemoglobin,deoxyhemoglobin,oxygen saturation,and collagen under tourniquet and cold stimulus tests to evaluate changes in the microcirculation of the nail *** quantitative analysis of multispectral PAT reconstructed images demonstrated heightened sensitivity in detecting alterations in blood oxygenation levels and collagen content within the nail bed,under simulated different physiological *** pilot study highlights the potential of PAT/US dual-modality imaging as a real-time,noninvasive diagnostic modality for evaluating human nail health and for early detection of nail bed pathologies.

关键词： Nail photoacoustic tomography ultrasound multi-modality quantitative parameter

First wetland mapping at 10-m spatial resolution in South America using multi-source and multi-feature remote sensing data

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Science China Earth Sciences 2024年第10期67卷 3252-3269页

作者： Weiwei SUN Gang YANG Yuling huang Dehua MAO Ke huang lin ZHU Xiangchao MENG Tian FENG Chao CHEN Yong GE Department of Geography and Spatial Information Techniques Ningbo UniversityNingbo 315211China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences&Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Natural Resources and Planning Bureau Shanghai Pudong New DistrictShanghai 200100China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China School of Geography Science and Geomatics Engineering Suzhou University of Science and TechnologySuzhou 215009China

Wetland degradation has been accelerating in recent years globally. Accurate information on the geographic distribution and categories of wetlands is essential for their conservation and management. Despite being the world′s fourth largest continent, South America has limited research on wetland mapping, and there is currently no available map that provides comprehensive information on wetland distribution and categories in the region. To address this issue, we used Sentinel-1, Sentinel-2 and SRTM data, developed a sample collection method and a wetland mapping method with a collection of multi-source features such as optical features, polarization features and shape features for South American wetlands. We produced a 10-m resolution wetland map based on the Google Earth Engine(GEE) platform. Our Level-1 wetland cover map accurately captured six wetland sub-categories with an overall accuracy of 96.24% and a kappa coefficient of 0.8649, while our Level-2 water cover map included five sub-categories with an overall accuracy of 97.23% and a kappa coefficient of0.9368. The results show that the total area of existing wetlands in South America is approximately 1,737,000 km~2, which is6.8% of the total land area. Among the ten wetland categories, shallow sea had the largest area(960,527.4 km~2), while aquaculture ponds had the smallest area 1513.6 km~2. Swamp had the second largest area(306,240.1 km~2). Brazil, Argentina,Venezuela, Bolivia, and Colombia were found to have the largest wetland areas, with Brazil and Colombia having the most diverse wetland categories. This product can serve as baseline data for subsequent monitoring, management, and conservation of South American wetlands.

关键词： Wetland mapping Google Earth Engine Sentinel imagery South America

Efficient Polytelluride Anchoring for Ultralong-Life Potassium Storage: Combined Physical Barrier and Chemisorption in Nanogrid-in-Nanofiber

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Nano-Micro Letters 2024年第4期16卷 364-378页

作者： Qinghua Li Dandan Yu Jian Peng Wei Zhang Jianlian huang Zhixin Liang Junling Wang Zeyu lin Shiyun Xiong Jiazhao Wang Shaoming huang guangzhou Key Laboratory of Low‑Dimensional Materials and Energy Storage Devices School of Materials and EnergyGuangdong University of TechnologyGuangzhou 510006People’s Republic of China College of Materials and Chemistry China Jiliang UniversityHangzhou 310018People’s Republic of China Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongInnovation CampusSquires WayNorth WollongongNSW 2522Australia

Metal tellurides(MTes) are highly attractive as promising anodes for high-performance potassium-ion batteries. The capacity attenuation of most reported MTe anodes is attributed to their poor electrical conductivity and large volume variation. The evolution mechanisms, dissolution properties, and corresponding manipulation strategies of intermediates(K-polytellurides, K-pTe_(x)) are rarely mentioned. Herein,we propose a novel structural engineering strategy to confine ultrafine CoTe_(2) nanodots in hierarchical nanogrid-in-nanofiber carbon substrates(CoTe_(2)@NC@NSPCNFs) for smooth immobilization of K-pTe_(x) and highly reversible conversion of CoTe_(2) by manipulating the intense electrochemical reaction process. Various in situ/ex situ techniques and density functional theory calculations have been performed to clarify the formation, transformation, and dissolution of K-pTe_(x)(K_(5)Te_(3) and K_(2)Te), as well as verifying the robust physical barrier and the strong chemisorption of K_(5)Te_(3) and K_(2)Te on S, N co-doped dual-type carbon substrates. Additionally, the hierarchical nanogrid-in-nanofiber nanostructure increases the chemical anchoring sites for K-pTe_(x), provides sufficient volume buffer space, and constructs highly interconnected conductive microcircuits, further propelling the battery reaction to new heights(3500 cycles at 2.0 A g^(-1)). Furthermore, the full cells further demonstrate the potential for practical applications. This work provides new insights into manipulating K-pTe_(x) in the design of ultralong-cycling MTe anodes for advanced PIBs.

关键词： Polytelluride dissolution Nanogrid-in-nanofiber structure Physicochemical adsorption Reaction mechanism Ultralonglife potassium storage

Z-scheme Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)heterojunctions enable exceptional visible photocatalytic degradation of organic pollutant

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Rare Metals 2024年第7期43卷 3161-3172页

作者： Feng huang Muhammad Humayun Gang Li Ting-Ting Fan Wen-lin Wang Yu-lin Cao Anton Nikiforov Chun-Dong Wang Jing Wang Key Laboratory of Analytical Science and Technology of Hebei Province Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of EducationState Key Laboratory of New Pharmaceutical Preparations and ExcipientsCollege of Chemistry and Materials ScienceHebei UniversityBaoding071002China Energy Water and Environment LabCollege of Humanities and SciencesPrince Sultan University11586 RiyadhSaudi Arabia Baoding Green Yijia Environmental Protection Technology Ltd Baoding 071051China Physics Laboratory Industrial Training CenterShenzhen Polytechnic UniversityShenzhen 518055China Department of Applied Physics Ghent University9000 GhentBelgium School of Integrated Circuits Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan 430074China

One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized ***,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(Ti)Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant *** NH_(2)-MIL-125(Ti)nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi_(4)O_(5)Br_(2).The as-prepared Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)presents more than 90%degradation of various pollutants,outperforming the counterpart individual *** various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials,in which the migration path of carriers from the material's interior to the surface can be reduced,in turn enhancing migration efficiency and separation capability significantly.A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors,radical trapping experiments and liquid chromatography mass spectrometry *** work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts,as well as the effective purification of wastewater in environmental remediation.

关键词： Z-scheme heterojunctions Photocatalysis Alkaline solution stripping Bi_(4)O_(5)Br_(2) NH_(2)-MIL-125(Ti)

Simulation and reconstruction of particle trajectories in the CEPC drift chamber

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Nuclear Science and Techniques 2024年第8期35卷 9-22页

作者： Meng‑Yao Liu Wei‑Dong Li Xing‑Tao huang Yao Zhang Tao lin Ye Yuan Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China Institute of High Energy Physics Beijing 100049China University of Chinese Academy of Sciences Beijing 100049China

The circular electron-positron collider(CEPC)is designed to precisely measure the properties of the Higgs boson,study electroweak interactions at the Z-boson peak,and search for new physics beyond the Standard *** a component of the 4th conceptual CEPC detector,the drift chamber facilitates the measurement of charged *** study implemented a Geant4-based simulation and track reconstruction for the drift *** the simulation,detector construction and response were implemented and added to the CEPC simulation *** development of track reconstruction involves track finding using the combinatorial Kalman filter method and track fitting using the tool of *** the simulated data,the tracking performance was *** results showed that both the reconstruction resolution and tracking efficiency satisfied the requirements of the CEPC experiment.

关键词： CEPC Drift chamber Detector simulation Track reconstruction

A review of ultra-high temperature heat-resistant energetic materials

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Defence Technology（防务技术） 2024年第8期38卷 33-57页

作者： Rongzheng Zhang Yuangang Xu Feng Yang Pengcheng Wang Qiuhan lin Hui huang Ming Lu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

Heat-resistant energetic materials refer to a type of energetic materials that possess a high melting point,high stability and operational safety. By studying the structures of these energetic materials has showed that the thermal stability can be enhanced by introducing amino groups to form intra/inter-molecular hydrogen bonds, constructing conjugate systems and designing symmetrical structures. This article aims to review the physical and chemical properties of ultra-high temperature heat-resistant energetic compounds and provide valuable theoretical insights for the preparation of ultra-high temperature heatresistant energetic materials. We also analyze the selected 20 heat-resistant energetic materials with decomposition temperatures higher than 350℃, serving as templates for the synthesis of various highperformance heat-resistant energetic materials.

关键词： Heat-resistant energetic materials Organic synthesis Conjugated Hydrogen bond Symmetrical structure Stabilization

桤木制浆造纸研究现状与我国桤木浆的开发利用

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林业科学研究 1999年第6期12卷 656-661页

作者：陈炳星周志春李光荣黄光霖杨林福建省南纸股份有限公司福建南平353000 中国林业科学研究院亚热带林业研究所浙江富阳311400

就桤木商用种植的生产潜力、制浆造纸和材性研究现状等进行综合评述。桤木是一种商用种植较有发展前景的阔叶树种，生长迅速、固氮能力强，木材性质类似于杨木和桦木，可用来开发研制不同的浆种，与针叶木浆或其它阔叶木浆配抄可以生产... 详细信息

就桤木商用种植的生产潜力、制浆造纸和材性研究现状等进行综合评述。桤木是一种商用种植较有发展前景的阔叶树种，生长迅速、固氮能力强，木材性质类似于杨木和桦木，可用来开发研制不同的浆种，与针叶木浆或其它阔叶木浆配抄可以生产高质量的印刷纸和书写纸等。鉴于我国丰富的桤木遗传资源和现有的生产经营水平，大力发展桤木纸浆原料林，开发利用桤木木浆具有广阔的前景，对于缓解针叶木浆之不足，降低纸浆生产成本，使我国造纸业在木材原料价格上处于竞争优势具有重要意义。

关键词：桤木制浆造纸木材性状开发利用

DynIceData:a gridded ice-water classification dataset at short-time intervals based on observations from multiple satellites over the marginal ice zone

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Big Earth Data 2024年第2期8卷 249-273页

作者： lin huang Yubao Qiu Yang Li Shuwen Yu Wanyang Zhong Changyong Dou Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijingChina International Research Center of Big Data for Sustainable Development Goals BeijingChina University of Chinese Academy of Sciences BeijingChina School of Resources and Geosciences China University of Mining and TechnologyXuzhouChina

High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the *** individual satellite sensors provide periodic sea ice obser-vations with spatial resolutions of tens of meters,information regarding changes that occur over short time intervals of minutes or hours is *** this study,a gridded ice-water classification dataset with a high temporal resolution was developed based on observations acquired by multiple satellite sensors in the Marginal Ice Zone(MIZ).This dataset-DynIceData-which combines Sentinel-1 Synthetic Aperture Radar(SAR)data with Gaofen-3(GF-3)SAR and SDGSAT-1 thermal infrared imagery was used to obtain observations of the MIZ with a range of temporal resolutions ran-ging from minutes to tens of *** areas of the Arctic covered include the Kara Sea,Beaufort Sea,and Greenland Sea during the period from August 2021 to August ***-oriented segmen-tation and thresholding were used to obtain the ice-water classifi-cation map from Sentinel-1 and GF-3 SAR image pairs and Sentinel-1 SAR and SDGSAT-1 thermal image *** time interval between the images in each pair ranged from 1 minute to 68 ***-kilometer grid sample granules with a spatial resolution of 25 m for the GF-3 SAR data and 30 m for the SDGSAT-1 thermal data were *** classification was verified as having an overall accuracy of at least 95.58%.The DynIceData dataset consists of 7338 samples,which could be used as reference data for further research on rapid changes in sea ice patterns at different short time scales and provide support for research on thermodynamic and dynamic models of sea ice in combination with other environmen-tal data,thus potentially improving the accuracy of sea ice forecast-ing using Artificial *** dataset can be accessed at https://***/10.57760/sciencedb.j00001.00784.

关键词： Sea ice dynamics ice-water classification GF-3 SDGSAT-1 marginal ice zone