检索结果-南通市图书馆

An audio‐based risky flight detection framework for quadrotors

IET Cyber-Systems and Robotics 2024年第1期6卷 1-14页

作者： Wansong Liu Chang Liu Seyedomid Sajedi Hao Su Xiao Liang Minghui Zheng department of Mechanical and aerospace Engineering University at BuffaloBuffaloNew YorkUSA department of Civil Structural and Environmental EngineeringUniversity at BuffaloBuffaloNew YorkUSA department of Mechanical and aerospace Engineering North Carolina State UniversityRaleighNorth CarolinaUSA

Drones have increasingly collaborated with human workers in some workspaces,such as *** failure of a drone flight may bring potential risks to human beings'life safety during some aerial *** of the most common flight failures is triggered by damaged *** quickly detect physical damage to propellers,recognise risky flights,and provide early warnings to surrounding human workers,a new and compre-hensive fault diagnosis framework is presented that uses only the audio caused by pro-peller rotation without accessing any flight *** diagnosis framework includes three components:leverage convolutional neural networks,transfer learning,and Bayesian ***,the audio signal from an actual flight is collected and trans-ferred into time–frequency ***,a convolutional neural network‐based diagnosis model that utilises these spectrograms is developed to identify whether there is any broken propeller involved in a specific drone ***,the authors employ Monte Carlo dropout sampling to obtain the inconsistency of diagnostic results and compute the mean probability score vector's entropy(uncertainty)as another factor to diagnose the drone ***,to reduce data dependence on different drone types,the convolutional neural network‐based diagnosis model is further augmented by transfer *** is,the knowledge of a well‐trained diagnosis model is refined by using a small set of data from a different *** modified diagnosis model has the ability to detect the broken propeller of the second ***,to reduce the hyperparameters'tuning efforts and reinforce the robustness of the network,Bayesian optimisation takes advantage of the observed diagnosis model performances to construct a Gaussian pro-cess model that allows the acquisition function to choose the optimal network *** proposed diagnosis framework is validated via real experimental flight tests and has a reasonably hig

关键词： aerial robotics deep learning flying robots propeller diagnosis

来源：

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

Long-lived lunar volcanism sustained by precession-driven core-mantle friction

引用

National Science Review 2024年第2期11卷 114-123页

作者： Shuoran Yu Xiao Xiao Shengxia Gong Nicola Tosi Jun Huang Doris Breuer Long Xiao Dongdong Ni State Key Laboratory of Lunar and Planetary sciences Macau University of Science and Technology Planetary Science Institute State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences CAS Key Laboratory of Planetary sciences Shanghai Astronomical Observatory Institute of Planetary Research German Aerospace Centre(DLR)

Core-mantle friction induced by the precession of the Moon's spin axis is a strong heat source in the deep lunar mantle during the early phase of a satellite's evolution, but its influence on the long-term thermal evolution still remains poorly explored. Using a one-dimensional thermal evolution model, we show that core-mantle friction can sustain global-scale partial melting in the upper lunar mantle until ～3.1 Ga, thus accounting for the intense volcanic activity on the Moon before ～3.0 Ga. Besides, core-mantle friction tends to suppress the secular cooling of the lunar core and is unlikely to be an energy source for the long-lived lunar core dynamo. Our model also favours the transition of the Cassini state before the end of the lunar magma ocean phase(～4.2 Ga), which implies a decreasing lunar obliquity over time after the solidification of the lunar magma ocean. Such a trend of lunar obliquity evolution may allow volcanically released water to be buried in the lunar regolith of the polar regions. As a consequence, local water ice could be more abundant than previously thought when considering only its accumulation caused by solar wind and comet spreading.

关键词： Moon precession orbit volcanism

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Comprehensive review on ethnomedicinal, phytochemistry and pharmacological profile of Ficus Religiosa L.

引用

Journal of Traditional Chinese Medicine 2024年第5期44卷 1052-1057页

作者： Rahul Rawat Harish Kumar Neetu Singh Aakash Deep Balasubramanian Narasimhan Surender Singh Yadav Sanjiv Kumar department of Pharmaceutical sciences Chaudhary Bansi Lal University department of Botany Maharshi Dayanand University Faculty of Pharmaceutical sciences Maharshi Dayanand University

Ficus religiosa L.(F. religiosa) or sacred fig is a large perennial tree belonging to the family Moraceae or mulberry family. Though the tree has pan-tropical distribution but originally it is indigenous to the Indian subcontinent and Indochina region. Popularly the tree is named "Pepal or bodhi tree". Traditionally, it is practiced for the treatment of asthma, nose bleeding, heart disorders, diabetes, wound healing, ear problems, constipation, hyperlipidemia, gonorrhea, ulcers and infectious disorders. Chemical analysis demonstrated the presence of numerous bioactives including tannins, phenols, saponins, sugars, alkaloids, methionine, terpenoids, flavonoids, glycosides, proteins, separated amino acids, essential and volatile oils and steroids etc., which are probably responsible for its diverse pharmacological actions. The present work is an attempt to compile up-to-date comprehensive information on F. religiosa that covers its taxonomy, ethnomedicinal importance, phytochemistry, pharmacological attributes and clinical trials. Keeping in mind the various health attributes of F. religiosa, future research can be aimed at in-depth elucidation of the structure-function relationship and multifactorial signalings pathways.

关键词： Ficus religiosa clinical trials ethnomedicine health benefits pharmacology phytoconstituents

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Regio-and Stereoselective Polymerization of Bio-based Ocimene by Rare-Earth Metal Catalysts

引用

Chinese Journal of Polymer Science 2024年第2期42卷 223-229,I0008页

作者： Qi-Yuan Wang Li-Peng Sang Zhen Zhang Yang Jiang Hui Tian Xia Zhao Xiang Guo Shi-Hui Li State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China Science and Technology on aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechonologyXiangyang441003China Shanxi Coal Chemical Industry Technology Research Institute Xi’an710000China Hubei Institute of aerospace Chemotechonology Xiangyang441003China

Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.

关键词： Biobased monomer Terpenes Ocimene Rare-earths Polymerization Regio/stereoselectivity Elastomer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Feature-aided pose estimation approach based on variational auto-encoder structure for spacecrafts

引用

Chinese Journal of Aeronautics 2024年第8期37卷 329-341页

作者： Yanfang LIU Rui ZHOU Desong DU Shuqing CAO Naiming QI department of aerospace Engineering Harbin Institute of TechnologyHarbin 150001China Suzhou Research Institute of HIT Suzhou 215104China Shanghai Institute of Spaceflight Control Technology Shanghai 201109China Shanghai Key Laboratory of aerospace Intelligent Control Technology Shanghai 201109China

Real-time 6 Degree-of-Freedom(DoF)pose estimation is of paramount importance for various on-orbit *** from the development of deep learning,Convolutional Neural Networks(CNNs)in feature extraction has yielded impressive achievements for spacecraft pose *** improve the robustness and interpretability of CNNs,this paper proposes a Pose Estimation approach based on Variational Auto-Encoder structure(PE-VAE)and a Feature-Aided pose estimation approach based on Variational Auto-Encoder structure(FA-VAE),which aim to accurately estimate the 6 DoF pose of a target *** methods treat the pose vector as latent variables,employing an encoder-decoder network with a Variational Auto-Encoder(VAE)*** enhance the precision of pose estimation,PE-VAE uses the VAE structure to introduce reconstruction mechanism with the whole ***,FA-VAE enforces feature shape constraints by exclusively reconstructing the segment of the target spacecraft with the desired *** evaluation against leading methods on public datasets reveals similar accuracy with a threefold improvement in processing speed,showcasing the significant contribution of VAE structures to accuracy enhancement,and the additional benefit of incorporating global shape prior features.

关键词： Pose estimation Variational auto-encoder Feature-aided Pose Estimation Approach On-orbit measurement tasks Simulated and experimental dataset

来源：

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

Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

引用

National Science Review 2024年第1期11卷 8-10页

作者： David J.Bottjer department of Earth sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

All-optical driven soft crawler with complexmotion capabilities

引用

International Journal of Smart and Nano Materials 2024年第2期15卷 348-364页

作者： Chenchu Zhang Jin Wang Linhan Zhao Renfei Chen Qiangqiang Zhao Jie Zhao Fating Liu Yucheng Bian Heng Zhang Yisen Wang Chaowei Wang Ying Hu Anhui Province Key Lab of aerospace Structural Parts Forming Technology and Equipment Institute of Industry and Equipment TechnologyHefei University of TechnologyHefeiChina CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision InstrumentationUniversity of Science and Technology of ChinaHefeiChina GBA Branch of aerospace Information Research Institute Chinese Academy of SciencesGuangzhouChina

The emergence of millimeter-scale soft actuators has signifi-cantly expanded the potential applications in areas such as search and rescue,drug delivery,and human assistance,due to their high *** these advancements,achieving precise control over the intricate movements of soft crawlers poses a significant *** this study,we have developed an all-optical approach that enables manipulation of propul-sive forces by simultaneously modifying the magnitude and direction of friction forces,thereby enabling complex motions of soft ***,the approach is not constrained by specific actuator shapes,and theoretically,any elongated photothermal actuator can be *** actuator was designed with an isosceles trapezoid shape,featuring a top width of 2mm,a bottom width of 4 mm,and a length of 8 *** our,manipulation approach,we showcase a proof-of-concept for complex soft robotic motions,including crawling(achieving speeds of up to 2.25 body lengths per minute),turning,avoiding obstacles,handling and trans-ferring objects approximately twice its own weight,and navi-gating narrow spaces along programmed *** results showcasethis all-optical manipulationapproach as a promising,yet unexplored tool for the precision and wireless control for the development of advanced soft actuators.

关键词： Light driven soft actuator all-optical manipulation laser manipulation

来源：

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

Late Ordovician Mass Extinction: Earth, fire and ice

引用

National Science Review 2024年第1期11卷 51-65页

作者： David A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A Blood Hepatocellular Carcinoma Signature Recognizes Very Small Tumor Nodules with Metastatic Traits

引用

Journal of Clinical and Translational Hepatology 2024年第6期12卷 551-561页

作者： Kun Chen Junxiao Wang Liping Jiang Fei Zhao Ruochan Zhang Zhiyuan Wu Dongmei Wang Yuchen Jiao Hui Xie Chunfeng Qu State Key Lab of Molecular Oncology Department of ImmunologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Senior department of Oncology Fifth Medical Center of Chinese PLA General HospitalBeijingChina aerospace Medical Center/aerospace Center Hospital Peking University Aerospace Clinical CollegeBeijingChina State Key Lab of Molecular Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Background and Aims:Hepatocellular carcinoma(HCC)cases with small nodules are commonly treated with radi-ofrequency ablation(RFA),but the recurrence rate remains *** study aimed to establish a blood signature for identifying HCC with metastatic traits ***:Data from HCC patients treated between 2010 and 2017 were retrospectively collected.A blood signature for meta-static HCC was established based on blood levels of alpha-fetoprotein and des-γ-carboxy-prothrombin,cell-free DNA(cfDNA)mutations,and methylation changes in target genes in frozen-stored plasma samples that were collected before RFA *** HCC blood signature was validated in patients prospectively enrolled ***:Of 251 HCC patients in the retrospective study,33.9% experienced recurrence within 1 year *** HCC blood signature identified from these patients included des-γ-carboxy-prothrombin≥40mAU/mL with cfDNA mutation score,where cfDNA mutations occurred in the genes of TP53,CTNNB1,and TERT *** signature effectively predicted 1-year post-RFArecurrence of HCC with 92% specificity and 91% sensitivity in the retrospective dataset,and with 87% specificity and 76% sensitivity in the prospective dataset(n=32 patients).Among 14 cases in the prospective study with biopsy tissues available,positivity for the HCC blood signature was associated with a higher HCC tissue score and shorter distance between HCC cells and ***:This study established an HCC blood signature in pre-RFA blood that potentially reflects HCC with metastatic traits and may be valuable for predicting the disease’s early recurrence post-RFA.

关键词： Liquid biopsy Liver dysplastic nodules Radiofrequency ablation Hepatocellular carcinoma Recurrence prediction Metastatic nodules

来源：

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

A dataset of lake level changes in China between 2002 and 2023 using multi-altimeter data

引用

Big Earth Data 2024年第1期8卷 166-188页

作者： Shanmu Ma Jingjuan Liao Ruofan Jing Jiaming Chen 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

Lake water levels are an important indicator of water balance and water cycles,and are essential for climate and environmental change studies and water resource ***,lake level measurements are scarce or inconsistent throughout the country,and traditional gauge measurements of many lakes are not feasible,so satellite altimetry is a vital alternative to gauge lake ***,the accuracy and sam-pling frequency of lake level time series are usually low because of time and space coverage limitations;therefore,it is necessary to utilize multialtimeter data to monitor lake levels and obtain lake level changes over long time *** this study,we extracted the water level changes in 988 lakes(>10 km^(2))in China between 2002 and 2023 based on ICESat/-2,Cryosat-2,Jason-1/2/3,and Sentinel-3A/3B altimetry data using waveform retracking,lake level extraction,lake level time series construction,the fusion of multi-altimeter lake level time series,and outlier removal.A total of 55%of the lakes in this dataset have been monitored for more than 10 years,and 34%have more than 12 times the annual average water level *** the same time,in situ data from 21 lakes were used for validation,and the average root mean square error(RMSE)for each of the datasets of ICESat/-2,Cryosat-2,Jason-1/2/3,and Sentinel-3A/3B versus the in situ lake levels are 0.223 m,0.163 m,0.207 m,0.596 m,0.295 m,0.275 m,0.243 m,and 0.317 m,respectively,and the mean RMSE of the fused lake levels reaches 0.332 *** the monitoring period,the water levels in Chinese lakes generally *** overall annual average rate of change at the 20 and 10-year scales was 0.123 m/a and 0.151 m/a,respectively,among which the overall water levels in large lakes increased *** lakes with a faster rate of decline in the water level were primarily *** water storage in each lake region in China shows an upward trend,with the most significant increase in the Tibetan Plateau reg

关键词： Lake level multi-altimeter China spatiotemporal variation

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：