检索结果-南通市图书馆

Data-driven discovery of linear dynamical systems from noisy data

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第1期67卷 121-129页

作者： wANG YaSen YUAN Ye FANG HuaZhen DING Han School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China department of Mechanical Engineering University of KansasLawrence 66045USA

In modern science and engineering disciplines,data-driven discovery methods play a fundamental role in system modeling,as data serve as the external representations of the intrinsic mechanisms within ***,empirical data contaminated by process and measurement noise remain a significant obstacle for this type of *** this study,we have developed a data-driven method capable of directly uncovering linear dynamical systems from noisy *** method combines the Kalman smoothing and sparse Bayesian learning to decouple process and measurement noise under the expectation-maximization framework,presenting an analytical method for alternate state estimation and system ***,the discovered model explicitly characterizes the probability distribution of process and measurement noise,as they are essential for filtering,smoothing,and stochastic *** have successfully applied the proposed algorithm to several simulation *** results demonstrate its potential to enable linear dynamical system discovery in practical applications where noise-free data are intractable to capture.

关键词： system identification sparse Bayesian learning Kalman smoothing process and measurement noise

Cosmological interpretation for the stochastic signal in pulsar timing arrays

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 43-50页

作者： Yu-Mei wu Zu-Cheng Chen Qing-Guo Huang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China department of Astronomy Beijing Normal UniversityBeijing 100875China Advanced Institute of Natural Sciences Beijing Normal UniversityZhuhai 519087China department of Physics and Synergistic Innovation Center for Quantum Effects and Applications Hunan Normal UniversityChangsha 410081China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

The pulsar timing array(PTA)collaborations have recently reported compelling evidence for a stochastic signal consistent with a gravitational-wave *** this paper,we combine the latest data sets from NANOGrav,PPTA,and EPTA to explore cosmological interpretations for the PTA signal from first-order phase transitions,domain walls,and cosmic strings,*** find that the domain wall model is strongly disfavored with the Bayes factors compared with the first-order phase transitions and cosmic strings being 1/90 and 1/189,respectively,breaking the degeneracy among these models in individual data *** also find that:(1)a strong phase transition at temperatures below the electroweak scale is favored,and the bubble collisions make the dominant contribution to the energy density spectrum;(2)a small reconnection probability pwed by strings in(super)string theory is favored at the 95%confidence level,and ground-based detectors can further constrain the parameter space.

关键词： puslar timing arrays gravitational-wave background first-order phase transitions domain walls cosmic strings

Unveiling the size effect of nitrogen-doped carbon-supported copper-based catalysts on nitrate-to-ammonia electroreduction

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 2438-2443页

作者： Ran Li Taotao Gao wenxi Qiu Minghao Xie Zhaoyu Jin Panpan Li College of Materials Science and Engineering Sichuan UniversityChengdu 610065China Institute for Advanced Study Chengdu UniversityChengdu 610106China Materials Science and Engineering Program and walker department of Mechanical Engineering The University of Texas at AustinAustinTexas 78712USA Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China

The electrocatalytic nitrate reduction reaction(NitRR)represents a promising approach toward achieving economically and environmentally sustainable ***,it remains a challenge to regulate the size effect of electrocatalysts to optimize the catalytic activity and ammonia ***,the Cu-based catalysts were tailored at the atomic level to exhibit a size gradient ranging from single-atom catalysts(SACs,0.15–0.35 nm)to single-cluster catalysts(SCCs,1.0–2.8 nm)and nanoparticles(NPs,20–30 nm),with the aim of studying the size effect for the NO_(3)^(-)-to-NH_(3) reduction ***,the Cu SCCs exhibit enhanced metal–substrate and metal–metal interactions by taking advantageous features of Cu SACs and Cu ***,Cu SCCs achieve exceptional electrocatalytic performance for the NitRR with a maximum Faradaic efficiency of ca.96%NH_(3)and the largest yield rate of ca.1.99 mg·h^(-1)·cm^(-2) at-0.5 V *** hydrogen electrode(RHE).The theoretical calculation further reveals the size effect and coordination environment on the high catalytic activity and selectivity for the *** work provides a promising various size-controlled design strategy for aerogel-based catalysts effectively applied in various electrocatalytic reactions.

关键词： nitrate electroreduction ammonia electrosynthesis size effect single-cluster catalyst

Preliminary exploration of animal models of congenital choledochal cysts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

world Journal of Gastroenterology 2024年第10期30卷 1420-1430页

作者： Shu-Hao Zhang Yue-Bin Zhang Duo-Te Cai Tao Pan Ken Chen Yi Jin wen-Juan Luo Zong-wei Huang Qing-Jiang Chen Zhi-Gang Gao department of General Surgery Children’s HospitalZhejiang University School of MedicineHangzhou 310000Zhejiang ProvinceChina

BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing *** surgical techniques can achieve satisfactory outcomes for treatment of ***,recent studies have focused more on clinical issues rather than basic ***,we need appropriate animal models to further basic *** To establish an appropriate animal model that may contribute to the investigation of the pathogenesis of *** Eighty-four specific pathogen-free female Sprague-Dawley rats were randomly allocated to a surgical group,sham surgical group,or control group.A rat model of CC was established by partial ligation of the bile *** reliability of the model was confirmed by measurements of serum biochemical indices,morpho-logy of common bile ducts of the rats as well as molecular biology experiments in rat and human *** Dilation classified as mild(diameter,≥1 mm towas observed in 17,17,and 2 rats in the surgical group,respectively,while no dilation was observed in the control and sham surgical *** levels of alanine aminotransferase,aspartate aminotrans-ferase,total bilirubin,direct bilirubin,and total bile acids were significantly elevated in the surgical group as compared to the control group 7 d after surgery,while direct bilirubin,total bilirubin,and gamma-glutamyltransferase were further increased 14 d after *** of the biochemical indices gradually decreased to normal ranges 28 d after *** protein expression trend of signal transducer and activator of transcription 3 in rat model was consistent with the human CC *** The model of partial ligation of the bile duct of juvenile rats could morphologically simulate the cystic or fusiform CC,which may contribute to investigating the pathogenesis of CC.

关键词： Choledochal cyst Animal model Partial ligation Cystic and fusiform dilation Juvenile rats

Defining failure of endoluminal biliary drainage in the era of endoscopic ultrasound and lumen apposing metal stents

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

world Journal of Gastroenterology 2024年第29期30卷 3534-3537页

作者： Faisal S Ali Sushovan Guha department of Gastroenterology Hepatologyand NutritionUniversity of Texas Health Science Center at HoustonHustonTX 77054United States department of Clinical Sciences Tilman J.Fertitta Family College of MedicineUniversity of HoustonHoustonTX 77204United States

The role of endoscopy in pathologies of the bile duct and gallbladder has seen notable advancements over the past two *** advancements in stent technology,such as the development of lumen-apposing metal stents,and adoption of endoscopic ultrasound and electrosurgical principles in therapeutic endoscopy,what was once considered endoscopic failure has transformed into failure of an approach that could be salvaged by a second-or third-line endoscopic *** of these advancements in routine patient care will require formal training and multidisciplinary acceptance of established techniques and collaboration for advancement of experimental techniques to generate robust evidence that can be utilized to serve patients to the best of our ability.

关键词： Endoscopic ultrasound Guided biliary drainage Gallbladder Biliary obstruction Lumen-apposing metal stent

Mechanistic insights toward identification and interaction of plant parasitic nematodes:A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Soil Ecology Letters 2024年第1期6卷 11-27页

作者： Bisma Jan Ali Haider Shah Mudasir Ahmad Bhat Arif Tasleem Jan Ishfaq Ahmad wani Ali Asghar Shah Section of Microbiology Baba Ghulam Shah Badshah UniversityRajouriJ&K185234India department of Biotechnology Baba Ghulam Shah Badshah University RajouriJ&K185234India department of Botany Baba Ghulam Shah Badshah University RajouriJ&K185234India department of Zoology School of Biosciences and BiotechnologyBaba Ghulam Shah Badshah University RajouriJ&K185234India

Nematode identification serves as an important param-eter to study their behaviour,importance and *** of classical morphometric based identifica-tion methods prove to be lacking due to insufficient knowledge on morphological variations among closely related *** approaches such as DNA and protein-based information,microarray,probing,sequence-based methods and others have been used to supplement morphology-based methods for nematode *** and certain protein-based nematode-associated molecular patterns(NAMPs),can be perceived by the host plants,and can initiate a signalling *** review primarily emphasizes on an updated account of different classical and modern tools used for the identification of *** we also summa-rize the mechanism of some important signalling pathways which are involved in the different plant nematode *** constitute most diverse and least studied group of soil inhabiting *** are ecologically and physiologically important,however,wide range of nematodes show harmful impact on the individuals that live within their *** parasitic nematodes(PPNs)are transparent,pseudocoelomate,free living or parasitic *** lack morphometric identification methods due to insufficient knowl-edge on morphological variations among closely related *** such,molecular approaches such as DNA and protein-based information,microarray,probing,sequence-based methods and others have been used to supplement morphology-based methods for their *** invade the defense response of different plant species,parasitic nematodes have evolved different molecular *** and certain protein-based nematode-associated molecular patterns(NAMPs),can be perceived by the host plants,and can initiate a signaling *** overcome the host confrontation and develop certain nematode feeding sites,some members can inject effectors into

关键词： nematode identification plant nematode interaction DNA fingerprinting nematode-associated molecular patterns signaling path-ways

Gender-Based Analysis of User Reactions to Facebook Posts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2024年第1期7卷 75-86页

作者： Yassine El Moudene Jaafar Idrais Rida El Abassi Abderrahim Sabour Mathematical Engineering and Computer Science Laboratory Faculty of SciencesIbn Zohr UniversityAgadir 8706Morocco department of Computer Science Mathematical−High School of Technology Ibn Zohr UniversityAgadir 8706Morocco

Online Social Networks(OSNs)are based on the sharing of different types of information and on various interactions(comments,reactions,and sharing).One of these important actions is the emotional reaction to the *** diversity of reaction types available on Facebook(namely FB)enables users to express their feelings,and its traceability creates and enriches the users’emotional identity in the virtual *** paper is based on the analysis of 119875012 FB reactions(Like,Love,Haha,wow,Sad,Angry,Thankful,and Pride)made at multiple levels(publications,comments,and sub-comments)to study and classify the users’emotional behavior,visualize the distribution of different types of reactions,and analyze the gender impact on emotion *** of these can be achieved by addressing these research questions:who reacts the most?which emotion is the most expressed?

关键词： profiling knowledge extraction data mining emotion mining social media data crawling Facebook reactions gender

Linking of Chemical Reactions and Silica Nanoparticle Contact Using Synthetic Helical Molecules

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第15期42卷 1781-1796页

作者： Sheng Zhang Ming Bao Mieko Arisawa Masahiko Yamaguchi state Key Laboratory of Fine Chemicals Dalian University of TechnologyDalianLiaoning 116024China department of Bioscience and Biotechnology Graduate Schoolof Bioresource and Bioenvironmental SciencesKyushu UniversityFukuoka 819-0395Japan

Biological cells exhibit diverse phenomena induced through linking of chemical reactions of molecules and solid surface *** is then a significant topic in the field of chemistry to study phenomena induced through this linking using synthetic systems,which can promote our understanding of biological phenomena and can be applied to the development of novel *** nanoparticles(sNPs),which are synthetic inorganic materials,are attractive for such purposes,because of their following characteristics:they can adsorb large amounts of molecules on their surfaces,they can aggregate through contact between SNPs as well as contact between molecules and SNPs,and the molecules can be easily removed from solutions by *** contact of sNP surfaces with molecules then affects chemical reactions of molecules and also behaviors of *** article describes systems derived from synthetic helical molecules and sNPs,which exhibit notable phenomena including selective adsorption and molecular recognition,equilibrium shift,step kinetics with induction period,precipitation with flow and sweeping,and disaggregation and desorption by sonication,in which the high affinity of helical molecules with sNP surfaces plays important *** models that explain the phenomena are *** applications are also discussed,including the separation of molecules,capture of intermediates,the storage and release of molecules,equilibrium shift,clocking,and the translation of mechanical stimulations into chemical reactions.

关键词： Silica nanoparticles Chemical reactions Molecular recognition Linking Nanoparticles Adsorption Chirality Precipitation

Velocity transformation for compressible wall-bounded turbulence——An approach through the mixing length hypothesis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 108-125页

作者： Xuke Zhu Yubin Song Xiaoshuo Yang Zhenhua Xia State Key Laboratory of Fluid Power and Mechatronic Systems and department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China

In an endeavor to establish a connection between the mean velocity profile in compressible wall-bounded turbulence and its incompressible analogue,a refined version of the Trettel and Larsson's(TL)transformation is systematically derived and rigorously assessed across diverse flow *** the recently proposed intrinsic compressibility effects and modeling the multi-layer structure of mixing lengths,the proposed transformation demonstrates exceptional performance in collapsing 57canonical flow cases,including cooled channel and pipe flows,channel flows with pseudo heat sources,as well as adiabatic and diabatic boundary layer ***,the transformation seamlessly extends to low Reynolds number cooled channel and pipe flows,achieving a level of accuracy unparalleled by other transformations in the current state-of-the-art.

关键词： mixing length hypothesis compressible wall-bounded turbulence velocity transformation law of the wall