检索结果-南通市图书馆

维普期刊数据库博看期刊

Phylogenetic pattern of alpine plants along latitude and longitude in Hengduan Mountains Region

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2017年第1期39卷 37-43页

作者： Xinhui Li hang sun College of Environmental Science and Engineering Southwest Forestry University Key Laboratory of Biodiversity and Biogeography Kunming Institute of Botany Chinese Academy of Sciences

To detect the horizontal pattern of phylogenetic structure shown by alpine plants, we measured phylogenetic structure using net related index(NRI) and net nearest taxon index(NTI), and analyzed the phylogenetic structure patterns of alpine plants along longitude, latitude and environmental gradients in the Hengduan Mountains Region(HDMR). Our results show that: 1) the phylogenetic structure tended to cluster with increasing latitude and longitude; 2) for NRI, latitude was closer related than longitude,while for NTI, longitude was closer related than latitude, though they both not significantly relate to *** phylogenetic structure tended towards overdispersion in the southern HDMR, with good climate conditions of higher mean annual temperature and more mean annual precipitation. In contrast, with harsh climate conditions of lower mean annual temperature and less mean annual precipitation, the increasing environmental stress led to phylogenetic clustering in the northern HDMR. The results highlighted that in the alpine region of HDMR, environmental filters and geographical isolation had a great effect on the latitudinal and longitudinal alpine species distribution, respectively.

关键词： Environmental filter Geographical isolation Hengduan Mountains Region Horizontal pattern NRI NTI

Model-data-driven P-wave impedance inversion using ResNets and the normalized zero-lag cross-correlation objective function

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第6期19卷 2711-2719页

作者： Yu-hang sun Yang Liu CNPC Key Laboratory of Geophysical Prospecting and State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China China University of Petroleum(Beijing) Karamay CampusKaramayXinjiang834000China

Model-driven and data-driven inversions are two prominent methods for obtaining P-wave impedance,which is significant in reservoir description and *** on proper initial models,most model-driven methods primarily use the limited frequency bandwidth information of seismic data and can invert P-wave impedance with high accuracy,but not high *** data-driven methods mainly employ the information from well-log data and can provide high-accuracy and highresolution P-wave impedance owing to the superior nonlinear curve fitting capacity of neural ***,these methods require a significant number of training samples,which are frequently *** obtain P-wave impedance with both high accuracy and high resolution,we propose a model-data-driven inversion method using Res Nets and the normalized zero-lag cross-correlation objective function which is effective for avoiding local minima and suppressing random *** using initial models and training samples,the proposed model-data-driven method can invert P-wave impedance with satisfactory accuracy and *** on synthetic and field data demonstrate the proposed method’s efficacy and practicability.

关键词： Model-data-driven P-wave impedance inversion Res Nets Zero-lag cross-correlation

Image Segmentation-P300 Selector: A Brain–Computer Interface System for Target Selection

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第5期79卷 2505-2522页

作者： hang sun Changsheng Li He Zhang Mechanical Engineering Nanjing University of Science and TechnologyNanjing210018China

Brain–computer interface (BCI) systems, such as the P300 speller, enable patients to express intentions withoutnecessitating extensive ***, the complexity of operational instructions and the slow pace of characterspelling pose challenges for some patients. In this paper, an image segmentation P300 selector based on YOLOv7-mask and DeepSORT is proposed. The proposed system utilizes a camera to capture real-world objects forclassification and tracking. By applying predefined stimulation rules and object-specificmasks, the proposed systemtriggers stimuli associated with the objects displayed on the screen, inducing the generation of P300 signals in thepatient’s brain. Its video processing mechanism enables the system to identify the target the patient is focusing oneven if the object is partially obscured, overlapped, moving, or changing in number. The system alters the target’scolor display, thereby conveying the patient’s intentions to caregivers. The data analysis revealed that the selfrecognitionaccuracy of the subjects using this method was between 92% and 100%, and the cross-subject P300recognition precision was 81.9%–92.1%. This means that simple instructions such as “Do not worry, just focuson what you desire” effectively discerned the patient’s intentions using the Image Segmentation-P300 selector. Thisapproach provides cost-effective support and allows patients with communication difficulties to easily express theirneeds.

关键词： Brain-computer interface deep learning electroencephalogram P300 YOLOv7-mask

Current progress and future prospects in phylofloristics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2018年第4期40卷 141-146页

作者： Rong Li Lishen Qian hang sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 China University of Chinese Academy of Sciences Beijing 100049 China

The species composition of regional plant assemblages can in large part be explained by a long history of biogeographical and evolutionary events. Traditional attempts of floristic studies typically focus on the analyses of taxonomic composition, often ignoring the rich context that evolutionary history can provide. In 2014, Swenson and Umafia introduced the term ＇phylofloristics＇ to define a phylogenetically enabled analysis of the species composition of regional floras. Integrating phylogenetic information into tradi- tional floristic analysis can provide a promising way to explore the ecological, biogeographic, and evolutionary processes that drive plant assemblies at multiple spatial scales. In this review, we sum- marize the current progress on the phylogenetic structure, spatial phylogenetic pattern, origin and diversification, phylogenetic regionalization of fioristic assemblages, and application of phylogenetic information in biodiversity conservation. These summaries highlight the importance of incorporating phylogenetic information to improve our understanding of floristic assembly from an evolutionary perspective. The review ends with a brief outlook on future challenges for phylofloristic studies, including generating a highly resolved species-level phylogenetic tree, compiling detailed and refined information regarding the geographic distribution of all plant life, extracting trait information from publications and herbarium specimens, and developing technological and methodological approaches for big data analysis.

关键词： Big data Biogeography Ecology Evolution Flora Mega-phylogeny

How cushion communities are maintained in alpine ecosystems： A review and case study on alpine cushion plant reproduction

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2017年第4期39卷 221-228页

作者： Jianguo Chen Yanbo Li Yang Yang hang sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming Yunnan China University of Chinese Academy of Sciences Beijing 100049 China

Cushion species occur in nearly all alpine environments worldwide. In past decades, the adaptive and ecosystem-engineering roles of such highly specialized life forms have been well studied. However, the adaptive strategies responsible for cushion species reproductive success and maintenance in severe alpine habitats remain largely unclear. In this study, we reviewed the current understanding of reproductive strategies and population persistence in alpine cushion species. We then present a preliminary case study on the sexual reproduction of Arenaria polytrichoides(Caryophyllaceae), a typical cushion species inhabiting high elevations of the Himalaya Hengduan Mountains, which is a hotspot for diversification of cushion species. Finally, we highlight the limitations of our current understanding of alpine cushion species reproduction and propose future directions for study.

关键词： Alpine ecosystem Cushion plant Community recruitment Growth rate Life-span Reproduction

Karyomorphology of three endemic plants(Brassicaceae:Euclidieae and Arabideae)from the Qinghai-Tibet Plateau and its significance

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2020年第3期42卷 135-141页

作者： Wenguang sun Haixia Wang Rui Wu hang sun Zhimin Li CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China School of Life Science Engineering Research Center of Sustainable Development and Utilization of Biomass EnergyYunnan Normal UniversityKunming 650500.China University of the Chinese Academy of Sciences Beijing 100049China

In the paper,chromosome number and karyotype of three endemic genera from China are reported for the first *** results show that Anzhengxia yechengnica has a karyotype formula2 n=2 x=14=6 m+8 sm and belongs to Stebbins-3 A;Shangrilaia nana karyotype formula is2 n=2 x=14=10 m+4 sm(2 sat) and belongs to Stebbins-1 A;Baimashania pulvinata karyotype formula is 2 n=2 x=16=12 m(2 sat)+4 sm and belongs to Stebbins-1 *** and Shangrilaia are monospecific genera belonging to tribe Euclidieae and both have a basic chromosome x=***,which belongs to tribe Arabideae,has two species which have a basic chromosome x=*** implications of these cytological data are compared with morphological support and the implications for each tribe are *** also summarize chromosomal number variation and its systematic implications of two tribes from the Qinghai-Tibet Plateau.

关键词： Karyotype Endemic species Anzhengxia Shangrilaia Baimashania Qinghai-Tibet Plateau

Is the East Asian flora ancient or not?

在线全文

学校读者我要写书评

暂无评论

National Science Review 2018年第6期5卷 920-932页

作者： Yong-Sheng Chen Tao Deng Zhuo Zhou hang sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of Sciences College of Life Science Northeast Agricultural University University of Chinese Academy of Sciences

The East Asian flora(EAF) is a key biodiversity hotspot for understanding the origin and evolution of Northern Hemisphere floras, but there is an ongoing debate on whether it is a museum or a cradle for seed plants. Within the EAF, two main floras, the Sino-Himalayan Flora(mainly the Rhododendron Flora) and the Sino-Japanese Flora(mainly the Metasequoia Flora), have been recognized. Previous studies suggested that the EAF is ancient and the Metasequoia Flora is older than the Rhododendron Flora. To test this hypothesis, we synthesized molecular as well as fossil data on seed plants, focusing on the biogeographical origins and historical evolution of the EAF. We compared the ages of its two constituent floras, and examined the impact of the Asian monsoon and other environmental changes on the development of EAF through meta-analysis. Our results suggest that the EAF might be relatively young, with most of its clades originating since the Miocene. The Rhododendron Flora and the Metasequoia Flora are probably of a similar age. The formation and development of the Asian monsoon might have been the main factors that have driven the evolution of EAF. In the Rhododendron Flora, the north-south mountain chains increased the concentration of species and reduced extinction, and the barriers between the east and west have resulted in species differentiation, which triggered it to become a diversity center. The EAF appears to have multiple biogeographical origins, having closely affiliated not only with other floras in the Northern Hemisphere, but also with Gondwanan floras.

关键词： Asian monsoon East Asian Flora Metasequoia Flora Rhododendron Flora temporal and spatial evolution

Steered coherence and entanglement in the Heisenberg XX chain under twisted boundary conditions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第7期30卷 139-144页

作者： Yu-hang sun Yu-Xia Xie School of Science Xi'an University of Posts and TelecommunicationsXi'an 710121China

We study steered coherence(SC)and entanglement in a three-spin Heisenberg XX model under twisted boundary conditions and show that their strengths can be significantly enhanced by tuning the twist *** optimal twist angleθ_(opt)for achieving the maximum l_(1) norm of SC isπin the region of weak field B and decreases gradually fromπto 0 when B increases after a critical value,while for the relative entropy of SC,θ_(opt)equalsπin the weak field region and 0 *** entanglement and the critical temperature above which the entanglement vanishes can also be significantly enhanced by tuning the twist angle from 0 toπ.

关键词： quantum coherence entanglement twisted boundary conditions

Global and regional tree species diversity

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2019年第2期12卷 210-215页

作者： Hong Qian Tao Deng hang sun Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA Key Laboratory for Plant Biodiversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China

Aims Understanding tree species richness at a global scale and the ori-gin and maintenance of patterns of tree species richness across the world is crucial to preserving tree species *** recently published global tree database(***)is the only source with tree lists at both global and national ***,our review and assessment show that many species included in GlobalTreeSearch are not tree *** addition,several thou-sands of tree species in the botanical literature have not been included in *** exact number of tree species in the world remains *** study aims to correct errors with GlobalTreeSearch and to estimate the number of tree species in the world based on a large number of regional *** We standardized nomenclature and spellings of the species names according to The Plant *** used 62 floristic sources,along with plant growth form and height,to assess the GlobalTreeSearch species checklist and to determine the degree to which GlobalTreeSearch incorrectly treated non-tree species as tree *** Findings Based on our review on 60.8%of the species in the GlobalTreeSearch database and the number of additional tree species that we have found from 62 continental,national,regional and local floris-tic sources,we found that about 8.7%of the species included in GlobalTreeSearch are not tree species(they are herbs,shrubs or vines).We estimate that there would be about 61000 tree species(including approximately 5500 species that are primarily shrubs but occasionally trees)in the world.

关键词： GlobalTreeSearch global tree species richness plant checklist national tree lists