期刊文献+
共找到100,554篇文章
< 1 2 250 >
每页显示 20 50 100
Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms 被引量:3
1
作者 Keyao Li Yiming Wang +6 位作者 Dapu Pi Baoli Li Haitao Luan Xinyuan Fang Peng Chen Yanqing Lu Min Gu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第1期28-35,共8页
Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since... Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display. 展开更多
关键词 holographic encryption optical secret sharing cascaded liquid crystal hologram multi-dimensional multiplexing
下载PDF
Assessment of the Drafting Quality of Request Forms Submitted to the Malaria and Parasitology Units at the Institut Pasteur de Cote d’Ivoire
2
作者 Yao Serge-Stéphane Ako Ako Bérenger Aristide +4 位作者 Sylvain Beourou Ouattara Yacouba N’Guessan Tiacoh Landry N’Dri Kouadio Thierry-Borel Toure André Offianan 《Journal of Biosciences and Medicines》 2024年第5期330-339,共10页
Biological tests provide information on the medical analysis requested by both the patient and the prescriber. It is a communication link between the prescriber and the laboratory staff. The lack of some information o... Biological tests provide information on the medical analysis requested by both the patient and the prescriber. It is a communication link between the prescriber and the laboratory staff. The lack of some information on request forms not only affects the drafting quality of the test and patient care, but could also make thousands of data produced by healthcare centers unusable. The aim of this study was to assess the drafting quality of request forms submitted to the Malaria and Parasitology Units at the Institut Pasteur de Côte d’Ivoire. Methods: It was a descriptive cross-sectional study to assess the drafting quality of request forms of various prescribers received at the Institut Pasteur de Côte d’Ivoire. This study was conducted at the Malaria and Parasitology Units, department of Parasitology and Mycology (Institut Pasteur de Côte d’Ivoire), from 6<sup>th</sup> December 2020 to 6<sup>th</sup> December 2021. The information on each request forms was recorded on a data collection form designed for this purpose. Each data collection form corresponds to a request forms and each test to a patient. Results: Out of a total of 1990 request forms received, the patient’s age and sex were missing on 18% and 26.8% of the tests respectively. More than half (51.80%) of request forms did not indicate the patient’s place of residence. Clinical information was not provided on 45.90% of the tests. Prescribers omitting their signatures were 51%, stamps were 50.3% and contacts were 71.2%. Only 5.4% of request forms were of good drafting quality. Providing all the required information on the forms could facilitate the use and analysis of data and samples. 展开更多
关键词 Laboratory QUALITY Request forms Information
下载PDF
Bioaccumulation,subcellular distribution and chemical forms of cadmium in Aster subulatus Michx.
3
作者 LIANG Xue-lian CHEN Wei +7 位作者 JIANG Wen-yan LIAO Jie YANG Yu-xia WANG Hai-jun LI Hui-ling LU Wei-fan WANG Tian-shun XIE Hong-zhao 《南方农业学报》 CAS CSCD 北大核心 2024年第8期2386-2395,共10页
【Objective】Through analyzing the bioaccumulation capacity,subcellular distribution and chemical forms of cadmium(Cd)in Aster subulatus Michx.,this study was to provide reference for revealing the Cd tolerance mechan... 【Objective】Through analyzing the bioaccumulation capacity,subcellular distribution and chemical forms of cadmium(Cd)in Aster subulatus Michx.,this study was to provide reference for revealing the Cd tolerance mechanism of A.subulatus Michx.【Method】After cultured for 24 d under the action of Hoagland nutrient solution and gradient Cd concentrations(0,30,60 and 90 mg/L),A.subulatus Michx.were harvested,and its leaf,stem and root were treated by differential centrifugation,chemical reagent extraction,and digested with graphite digester,respectively,then the Cd content in the root,stem and leaf were determined by atomic absorption spectroscopy.【Result】The experimental results indicated that the bioaccumulation capacity of Cd in A.subulatus Michx.was root>stem>leaf,and the maximum Cd concentration in the root,stem and leaf of A.subulatus Michx.were 130.74,78.69 and 56.62 mg/kg(fresh matter),respectively.Most of Cd stored in the cell wall and the soluble fractions of the root and leaf of A.subulatus Michx.,with only a smaller portion Cd in organelle fraction.Analysis result of subcellular Cd content showed that 52.27%-58.61%of Cd for root was mainly stored in the soluble fraction,but 42.10%-63.28%of Cd for leaf was mainly stored in the cell wall fraction.The concentration of pectates and protein integrated-Cd was higher in the root and leaf compared to other chemical forms Cd.Pectates and protein integrated-Cd was the main chemical forms Cd in the root and leaf of A.subulatus Michx.,and their percentages were 68.91%-74.80%and 57.38%-83.80%,respectively.Cd treatment could significantly increase the proportion of water-soluble organic acid Cd from 13.64%to 22.72%in root and undissolved phosphate Cd from 10.02%to 32.78%in leaf with increasing Cd concentration in the culture medium.【Conclusion】The root,stem and leaf of A.subulatus Michx.has strong bioaccumulation capacity to Cd,Cd is primarily stored in the soluble fractions of the root and cell wall fractions of the leaf,and less toxic pectates and protein integrated-Cd is the main chemical forms Cd in the root and leaf of A.subulatus Michx.,this might be the main mechanism of Cd tolerance in A.subulatus Michx. 展开更多
关键词 Aster subulatus Michx. CADMIUM BIOACCUMULATION chemical form subcellular distribution
下载PDF
Familial Forms of Spondyloarthritis Study of 100 Senegalese Multiplex Families
4
作者 Adama Bah Chiekh Ahamadou Bamba Diaw +10 位作者 Dieynaba Sala Tamara Kane Adama Doucouré Siddiki Charifah Ramadhane Bouchrane Harine Abdel Aziz Garba Aissatou N’diaye Mondukpe Joane Immanuelle Houansou Laurine Marlyse Adogle Yaye Aminata Gueye Moustapha Niasse Saidou Diallo 《Open Journal of Rheumatology and Autoimmune Diseases》 2024年第3期132-143,共12页
Introduction: Spondyloarthritis (SpA) comprises a group of chronic inflammatory rheumatic diseases characterized by predominant axial involvement. These include ankylosing spondylitis (AS), reactive arthritis (ReA), p... Introduction: Spondyloarthritis (SpA) comprises a group of chronic inflammatory rheumatic diseases characterized by predominant axial involvement. These include ankylosing spondylitis (AS), reactive arthritis (ReA), psoriatic arthritis (PsA), arthritis associated with inflammatory bowel diseases (IBD), SAPHO syndrome (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis), juvenile spondyloarthritis (JSPA), and undifferentiated SpA. Their exact cause is unknown but is believed to stem from a combination of factors. The first familial forms were described by de Blécourt et al. in 1961. The objective was to evaluate the epidemiological, clinical, therapeutic and evolutionary aspects of familial forms of SpA and in particular, to prove the severity of the disease in family members compared to index cases in the rheumatology department of the Aristide Le Dantec University Hospital in Dakar. Methodology: This was a prospective, cross-sectional and descriptive study with an analytical aim on patients with the familial form of spondyloarthritis defined by the existence of at least one other family member with SpA outside the propositus, collected within the Aristide Le Dantec rheumatology department in Dakar over a period of 10 years between January 2012 and December 2021. There were two phases of study, the first of which consisted of collecting index cases with miserly SpA and the second of which consisted of family screening after consent. The data analysed were epidemiological, clinical, paraclinical, therapeutic and evolving. Results: Out of 100 families of 1905 members, 667 SpA patients included, i.e. a prevalence of 35%, including 225 (33.73%) men and 412 women (61.17%), i.e. a ratio of 1.8. The mean age at diagnosis among relatives was 26.3 years (range 13 and 80 years), 47.14 years among the propositus, in whom the mean age at onset was 36.26 years and that of relatives 49.9 years in the first degree, 15 years in the second degree and 1 year in the third degree. The time to diagnosis was 11.20 years in the first degree, 2.5 years in the second degree, 1 year in the third degree and 10.88 years in the case of the proposes. The number of marriages in families was 420 of which 116 were consanguineous (consanguinity rate 27.62%), 19% among the propositus. HLA-B27 positive in 92% of the proposers and 33.43% in the families;70% of the propositus had an inflammatory syndrome and 17.54% in the families;87% of sacroilliitis in the propositus and 5.54% in the families. Clinical forms were dominated by undifferentiated SpA (338 cases) and APS (295 cases). The average BASFI was 3.23 on D0;2.59 in the 3rd month and 1 in the 6th month for the propositus versus 2.55 at D0;1.86 at the 3rd month and 1.55 in the 6th month in the families. Average BASDAI was 3.92 at D0;3.12 at the 3rd month and 2.07 at the 6th month in the propositus and 3 at D0;2.21 at the 3rd month and 1 at the 6th month in the families. Autoimmune associated conditions were 18 cases, degenerative 24 cases, autoinflammatory 2 metabolic cases 18 cases. They all received: NSAIDs, methotrexate, salazopyrine (11 cases) and anti-TNF-α (1 case). The evolution was generally favourable. Conclusion: SpA is on the rise in Senegalese hospitals, frequent in young people, SPA and undifferentiated SpA are the most frequent, management is essentially based on conventional care, and the disease is less severe in family members than index cases. 展开更多
关键词 Familial forms of Spondyloarthritis Propositus Senegal
下载PDF
Schur Forms and Normal-Nilpotent Decompositions
5
作者 LI Zhen 《应用数学和力学》 CSCD 北大核心 2024年第9期1200-1211,共12页
Real and complex Schur forms have been receiving increasing attention from the fluid mechanics community recently,especially related to vortices and turbulence.Several decompositions of the velocity gradient tensor,su... Real and complex Schur forms have been receiving increasing attention from the fluid mechanics community recently,especially related to vortices and turbulence.Several decompositions of the velocity gradient tensor,such as the triple decomposition of motion(TDM)and normal-nilpotent decomposition(NND),have been proposed to analyze the local motions of fluid elements.However,due to the existence of different types and non-uniqueness of Schur forms,as well as various possible definitions of NNDs,confusion has spread widely and is harming the research.This work aims to clean up this confusion.To this end,the complex and real Schur forms are derived constructively from the very basics,with special consideration for their non-uniqueness.Conditions of uniqueness are proposed.After a general discussion of normality and nilpotency,a complex NND and several real NNDs as well as normal-nonnormal decompositions are constructed,with a brief comparison of complex and real decompositions.Based on that,several confusing points are clarified,such as the distinction between NND and TDM,and the intrinsic gap between complex and real NNDs.Besides,the author proposes to extend the real block Schur form and its corresponding NNDs for the complex eigenvalue case to the real eigenvalue case.But their justification is left to further investigations. 展开更多
关键词 Schur form normal matrix nilpotent matrix tensor decomposition vortex identification
下载PDF
Evaluation of Laboratory Request Forms Completion in a Tertiary Medical Laboratory of the Democratic Republic of Congo
6
作者 Mamy Ngole Dahlia Pambu +3 位作者 Nathan Luana Dophie Tshibuela Ritha Nyembu Kibambe Bizette Bizeti Nsangu 《Journal of Biosciences and Medicines》 2024年第6期94-100,共7页
Background: The inadequacy in the completeness of the Laboratory Request Form (LRF) has been reported as one of the major sources of errors during the pre-analytical step of laboratory analysis. To prevent the occurre... Background: The inadequacy in the completeness of the Laboratory Request Form (LRF) has been reported as one of the major sources of errors during the pre-analytical step of laboratory analysis. To prevent the occurrence of such errors, this study aimed at assessing the level of completeness of LRFs. Methods: A retrospective analysis of laboratory request forms was conducted at the Clinical Biology Laboratory of the Kinshasa University Clinic, DR Congo, between November 2021 to May 2022. The LRFs were evaluated according to the completeness of all sections including administrative data of the patient, data of physician who ordered the test, relevant patient’s clinical data and data of the biological sample. Results: From a total of 2842 LRFs evaluated, none was fully completed with all required information. Particularly, patient’s clinical data including the medical history, provisional diagnosis and current treatment, were the most absent in 99% LRFs. However, two sections related to patient’s ID and prescribed test were informed in 100% LRFs. Conclusion: The results of this preanalytical audit can serve as an improvement opportunity focused on strengthening awareness about complete filling of LRF. 展开更多
关键词 AUDIT Laboratory Requisition form Clinical Biology Laboratory COMPLETENESS
下载PDF
Intelligent 6G Wireless Network with Multi-Dimensional Information Perception 被引量:1
7
作者 YANG Bei LIANG Xin +3 位作者 LIU Shengnan JIANG Zheng ZHU Jianchi SHE Xiaoming 《ZTE Communications》 2023年第2期3-10,共8页
Intelligence and perception are two operative technologies in 6G scenarios.The intelligent wireless network and information perception require a deep fusion of artificial intelligence(AI)and wireless communications in... Intelligence and perception are two operative technologies in 6G scenarios.The intelligent wireless network and information perception require a deep fusion of artificial intelligence(AI)and wireless communications in 6G systems.Therefore,fusion is becoming a typical feature and key challenge of 6G wireless communication systems.In this paper,we focus on the critical issues and propose three application scenarios in 6G wireless systems.Specifically,we first discuss the fusion of AI and 6G networks for the enhancement of 5G-advanced technology and future wireless communication systems.Then,we introduce the wireless AI technology architecture with 6G multidimensional information perception,which includes the physical layer technology of multi-dimensional feature information perception,full spectrum fusion technology,and intelligent wireless resource management.The discussion of key technologies for intelligent 6G wireless network networks is expected to provide a guideline for future research. 展开更多
关键词 6G wireless network artificial intelligence multi-dimensional information perception full spectrum fusion
下载PDF
Vanishing Theorems for p-Harmonic Forms on Submanifolds in Spheres
8
作者 Nan Li 《Journal of Contemporary Educational Research》 2024年第4期48-53,共6页
In this paper,we present some vanishing theorems for p-harmonic forms on-super stable complete submanifold M immersed in sphere Sn+m.When 2≤1≤n-2,M has a flat normal bundle.Assuming that M is a minimal submanifold ... In this paper,we present some vanishing theorems for p-harmonic forms on-super stable complete submanifold M immersed in sphere Sn+m.When 2≤1≤n-2,M has a flat normal bundle.Assuming that M is a minimal submanifold andδ>1(n-1)p2/4n[p-1+(p-1)2kp],we prove a vanishing theorem for p-harmonicℓ-forms. 展开更多
关键词 p-harmonic forms Vanishing theorems SUBMANIFOLDS
下载PDF
The Path,Trends,and Approaches of the Civilization Evolution of Rural Marriage Forms
9
作者 Renxiu Chen 《Review of Educational Theory》 2024年第1期6-9,共4页
Rural marriage has characteristics such as close relationship with labor production,deep integration of traditional culture,shy and introverted expression of subjective emotions,and illegal and rough marriage.The civi... Rural marriage has characteristics such as close relationship with labor production,deep integration of traditional culture,shy and introverted expression of subjective emotions,and illegal and rough marriage.The civilization evolution of rural marriage forms is moving towards a path that is conducive to the development of production and the pursuit of happiness for farmers,the construction of rural spiritual civilization,and the comprehensive development of rural society.This study analyzes the direction of the evolution of rural marriage form civilization,predicts the trend of rural marriage form civilization evolution,and proposes the future path of rural marriage form civilization evolution,including adhering to human’s most original value expectations of marriage life,drawing nourishment from excellent traditional Chinese culture,and continuously adjusting marriage and family policy tools to keep up with changes in the world of life. 展开更多
关键词 Rural Marriage forms Civilization Evolution Marriage Squeeze Civilized Rationality
下载PDF
基于WinForm窗体的光谱扫描系统设计
10
作者 黄利强 《信息与电脑》 2024年第17期117-120,共4页
目前,国内市场上广泛使用的紫外–可见分光光度计、紫外–荧光分光光度计大部分不具备自动波长扫描功能,只能人工操作和读数,因此使用受到了极大的限制。本文设计了一款基于Visual C#WinForm窗体的光谱仪软件,通过串口接收紫外–可见分... 目前,国内市场上广泛使用的紫外–可见分光光度计、紫外–荧光分光光度计大部分不具备自动波长扫描功能,只能人工操作和读数,因此使用受到了极大的限制。本文设计了一款基于Visual C#WinForm窗体的光谱仪软件,通过串口接收紫外–可见分光光度计、紫外–荧光分光光度计等光谱仪器的检测数据,并在电脑端对数据进行处理后,可以自动计算出吸光度、透光率、荧光强度等光谱参数,直观地显示波长扫描光谱图。 展开更多
关键词 C# Win form Visual Studio 光谱扫描系统
下载PDF
Seismic fragility analysis of highway bridges considering multi-dimensional performance limit state 被引量:16
11
作者 Wang, Qi'ang Wu, Ziyan Liu, Shukui 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2012年第2期185-193,共9页
Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility... Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility that considers multi-dimensional performance limit state parameters and makes a first attempt to develop fragility curves for a multi-span continuous (MSC) concrete girder bridge considering two performance limit state parameters: column ductility and transverse deformation in the abutments. The main purpose of this paper is to show that the performance limit states, which are compared with the seismic response parameters in the calculation of fragility, should be properly modeled as randomly interdependent variables instead of deterministic quantities. The sensitivity of fragility curves is also investigated when the dependency between the limit states is different. The results indicate that the proposed method can be used to describe the vulnerable behavior of bridges which are sensitive to multiple response parameters and that the fragility information generated by this method will be more reliable and likely to be implemented into transportation network loss estimation. 展开更多
关键词 highway bridge seismic hazard multi-dimensional performance limit state fragility curves sensitivity
下载PDF
Development and Evolution of Papermaking in Ancient China based on the Uses and Forms of Paper 被引量:1
12
作者 Xiaohui Yi 《Paper And Biomaterials》 CAS 2023年第3期38-46,共9页
In the past,scholars have divided the history of Chinese papermaking into different stages based on the development of ancient papermaking technology,emphasizing the development and progress of papermaking in differen... In the past,scholars have divided the history of Chinese papermaking into different stages based on the development of ancient papermaking technology,emphasizing the development and progress of papermaking in different historical periods but paying less attention to the changes in the form of paper.Here,the stages are defined based on changes in use and function rather than technological developments.When this approach is combined with the history of printing,books,calligraphy,and painting,the history of Chinese papermaking can be divided into the writing paper,writing and printing paper,printing paper,and calligraphy and painting paper periods.Different periods of paper have significant differences in texture,form,and performance owing to their different applications.This significant difference provides a reference for the identification of ancient papers and reveals the internal connection between the history of printing,books,calligraphy,painting,and papermaking. 展开更多
关键词 papermaking in ancient China uses and forms printing history CALLIGRAPHY painting history
下载PDF
Envelope Method and More General New Global Structures of Solutions for Multi-dimensional Conservation Law
13
作者 Gui-Qin Qiu Gao-Wei Cao +1 位作者 Xiao-Zhou Yang Yuan-An Zhao 《Communications on Applied Mathematics and Computation》 2023年第3期1180-1234,共55页
For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will b... For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will be generated.In this paper,by proposing and investigating the plus envelope,the minus envelope,and the mixed envelope of 2D non-selfsimilar rarefaction wave surfaces,we obtain and the prove the new structures and classifications of interactions between the 2D non-selfsimilar shock wave and the rarefaction wave.For the cases of the plus envelope and the minus envelope,we get and prove the necessary and sufficient criterion to judge these two envelopes and correspondingly get more general new structures of 2D solutions. 展开更多
关键词 Riemann problem Non-selfsimilar shock wave Non-selfsimilar rarefaction wave ENVELOPE multi-dimensional conservation law
下载PDF
Research and Practice on the Multi-dimensional Course Goal Achievement Evaluation of Software Engineering
14
作者 Ying Jiang Hongbin Wang Jiaman Ding 《计算机教育》 2023年第12期265-271,共7页
According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteris... According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteristics of hybrid teaching in Kunming University of Science and Technology.Then a multi-dimensional evaluation system for course goal achievement of software engineering is proposed.The practice’s results show that the multi-dimensional course goal achievement evaluation is helpful to the continuous improvement of course teaching,which can effectively support the evaluation of graduation outcomes. 展开更多
关键词 Software engineering Course goal achievement evaluation multi-dimensional
下载PDF
An Ordinal Multi-Dimensional Classification(OMDC)for Predictive Maintenance
15
作者 Pelin Yildirim Taser 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1499-1516,共18页
Predictive Maintenance is a type of condition-based maintenance that assesses the equipment's states and estimates its failure probability and when maintenance should be performed.Although machine learning techniq... Predictive Maintenance is a type of condition-based maintenance that assesses the equipment's states and estimates its failure probability and when maintenance should be performed.Although machine learning techniques have been frequently implemented in this area,the existing studies disregard to the nat-ural order between the target attribute values of the historical sensor data.Thus,these methods cause losing the inherent order of the data that positively affects the prediction performances.To deal with this problem,a novel approach,named Ordinal Multi-dimensional Classification(OMDC),is proposed for estimating the conditions of a hydraulic system's four components by taking into the natural order of class values.To demonstrate the prediction ability of the proposed approach,eleven different multi-dimensional classification algorithms(traditional Binary Relevance(BR),Classifier Chain(CC),Bayesian Classifier Chain(BCC),Monte Carlo Classifier Chain(MCC),Probabilistic Classifier Chain(PCC),Clas-sifier Dependency Network(CDN),Classifier Trellis(CT),Classifier Dependency Trellis(CDT),Label Powerset(LP),Pruned Sets(PS),and Random k-Labelsets(RAKEL))were implemented using the Ordinal Class Classifier(OCC)algorithm.Besides,seven different classification algorithms(Multilayer Perceptron(MLP),Support Vector Machine(SVM),k-Nearest Neighbour(kNN),Decision Tree(C4.5),Bagging,Random Forest(RF),and Adaptive Boosting(AdaBoost))were chosen as base learners for the OCC algorithm.The experimental results present that the proposed OMDC approach using binary relevance multi-dimensional classification methods predicts the conditions of a hydraulic system's multiple components with high accuracy.Also,it is clearly seen from the results that the OMDC models that utilize ensemble-based classification algorithms give more reliable prediction performances with an average Hamming score of 0.853 than the others that use traditional algorithms as base learners. 展开更多
关键词 Machine learning multi-dimensional classification ordinal classification predictive maintenance
下载PDF
Data inversion of multi-dimensional magnetic resonance in porous media
16
作者 Fangrong Zong Huabing Liu +1 位作者 Ruiliang Bai Petrik Galvosas 《Magnetic Resonance Letters》 2023年第2期127-139,I0004,共14页
Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension all... Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension allows the study of the correlation,exchange processes,and separation of overlapping spectral information.The multi-dimensional concept has been re-implemented over the last two decades to explore molecular motion and spin dynamics in porous media.Apart from Fourier transform,methods have been developed for processing the multi-dimensional time-domain data,identifying the fluid components,and estimating pore surface permeability via joint relaxation and diffusion spectra.Through the resolution of spectroscopic signals with spatial encoding gradients,multi-dimensional MR imaging has been widely used to investigate the microscopic environment of living tissues and distinguish diseases.Signals in each voxel are usually expressed as multi-exponential decay,representing microstructures or environments along multiple pore scales.The separation of contributions from different environments is a common ill-posed problem,which can be resolved numerically.Moreover,the inversion methods and experimental parameters determine the resolution of multi-dimensional spectra.This paper reviews the algorithms that have been proposed to process multidimensional MR datasets in different scenarios.Detailed information at the microscopic level,such as tissue components,fluid types and food structures in multi-disciplinary sciences,could be revealed through multi-dimensional MR. 展开更多
关键词 multi-dimensional MR Data inversion Porous media Inverse Laplace transform FOURIERTRANSform
下载PDF
Performance-based global reliability assessment of a high-rise frame-core tube structure subjected to multi-dimensional stochastic earthquakes 被引量:2
17
作者 Liu Zhangjun Ruan Xinxin Liu Zixin 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2022年第2期395-415,共21页
When evaluating the seismic safety and reliability of complex engineering structures,it is a critical problem to reasonably consider the randomness and multi-dimensional nature of ground motions.To this end,a proposed... When evaluating the seismic safety and reliability of complex engineering structures,it is a critical problem to reasonably consider the randomness and multi-dimensional nature of ground motions.To this end,a proposed modeling strategy of multi-dimensional stochastic earthquakes is addressed in this study.This improved seismic model has several merits that enable it to better provide seismic analyses of structures.Specifically,at first,the ground motion model is compatible with the design response spectrum.Secondly,the evolutionary power spectrum involved in the model and the design response spectrum are constructed accordingly with sufficient consideration of the correlation between different seismic components.Thirdly,the random function-based dimension-reduction representation is applied,by which seismic modeling is established,with three elementary random variables.Numerical simulations of multi-dimensional stochastic ground motions in a specific design scenario indicate the effectiveness of the proposed modeling strategy.Moreover,the multi-dimensional seismic response and the global reliability of a high-rise frame-core tube structure is discussed in detail to further illustrate the engineering applicability of the proposed method.The analytical investigations demonstrate that the suggested stochastic model of multi-dimensional ground motion is available for accurate seismic response analysis and dynamic reliability assessment of complex engineering structures for performance-based seismic resistance design. 展开更多
关键词 multi-dimensional stochastic ground motion dimension-reduction representation frame-core tube structure global dynamic reliability performance-based seismic design
下载PDF
Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence 被引量:1
18
作者 Jiazhen ZHAO Shengping HE +2 位作者 Ke FAN Huijun WANG Fei LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第8期1465-1482,共18页
Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Ar... Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions scenario.Thereafter, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained). 展开更多
关键词 wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence
下载PDF
Subcellular Distribution and Chemical Forms of Cadmium in the Medicine Food Homology Plant Platycodon grandiflorum(Jacq.)A.DC.
19
作者 Jia An Xiang Wang +7 位作者 Yajiang Jing Jianping Huang Qilong Wang Gang Zhang Jing Gao Liang Peng Wenli Huang Yonggang Yan 《Phyton-International Journal of Experimental Botany》 SCIE 2023年第5期1405-1420,共16页
Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd ... Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd levels to be regulated or reduced,it is necessary to first elucidate the mechanism of Cd uptake and accumulation in the plant,in addition to its detoxification mechanisms.This present study used inductively couple plasma-mass-spectrometry to analyze the subcellular distribution and chemical forms of Cd in different tissues of P.grandiflorum.The experimental results showed that Cd was mainly accumulated in the roots[predominantly in the cell wall(50.96%-61.42%)],and it was found primarily in hypomobile and hypotoxic forms.The proportion of Cd in the soluble fraction increased after Cd exposure,and the proportion of insoluble phosphate Cd and oxalate Cd increased in roots and leaves,with a higher increase in oxalate Cd.Therefore,it is likely that root retention mechanisms,cell wall deposition,vacuole sequestration,and the formation of low mobility and low toxicity forms are tolerance strategies for Cd detoxification used by P.grandiflorum.The results of this study provide a theoretical grounding for the study of Cd accumulation and detoxification mechanisms in P.grandiflorum,and they can be used as a reference for developing Cd limits and standards for other medicine food homology plants. 展开更多
关键词 CADMIUM Platycodon grandiflorum inductively coupled plasma-mass-spectrometry subcellular distribution chemical forms heavy metal tolerance medicine food homology
下载PDF
Microstructure and forming mechanism of metals subjected to ultrasonic vibration plastic forming: A mini review
20
作者 Qinghe Cui Xuefeng Liu +4 位作者 Wenjing Wang Shaojie Tian Vasili Rubanik Vasili Rubanik Jr. Dzmitry Bahrets 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第6期1322-1332,共11页
Compared with traditional plastic forming,ultrasonic vibration plastic forming has the advantages of reducing the forming force and improving the surface quality of the workpiece.This technology has a very broad appli... Compared with traditional plastic forming,ultrasonic vibration plastic forming has the advantages of reducing the forming force and improving the surface quality of the workpiece.This technology has a very broad application prospect in industrial manufactur-ing.Researchers have conducted extensive research on the ultrasonic vibration plastic forming of metals and laid a deep foundation for the development of this field.In this review,metals were classified according to their crystal structures.The effects of ultrasonic vibration on the microstructure of face-centered cubic,body-centered cubic,and hexagonal close-packed metals during plastic forming and the mech-anism underlying ultrasonic vibration forming were reviewed.The main challenges and future research direction of the ultrasonic vibra-tion plastic forming of metals were also discussed. 展开更多
关键词 ultrasonic vibration plastic forming crystal structure MICROSTRUCTURE forming mechanism
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部