期刊文献+
共找到117,261篇文章
< 1 2 250 >
每页显示 20 50 100
ICP-MS Analysis of Inorganic Elements in Astragalus membranaceus from Gansu Province
1
作者 Juandi WANG Zhiqiang ZHANG +4 位作者 Yifan YU Xiao MA Ruifeng YANG Yuanjun LANG Ruijuan ZHU 《Medicinal Plant》 2025年第3期5-9,14,共6页
[Objectives]To investigate the content and distribution of inorganic elements in Astragalus membranaceus sourced from various regions in Gansu Province.[Methods]28 batches of A.membranaceus samples were collected and ... [Objectives]To investigate the content and distribution of inorganic elements in Astragalus membranaceus sourced from various regions in Gansu Province.[Methods]28 batches of A.membranaceus samples were collected and subsequently digested using the Multiwave 7000 super microwave digestion system.The contents of aluminum(Al),barium(Ba),beryllium(Be),cobalt(Co),chromium(Cr),iron(Fe),gallium(Ga),magnesium(Mg),manganese(Mn),nickel(Ni),antimony(Sb),tin(Sn),strontium(Sr),titanium(Ti),thallium(Tl),vanadium(V),and zinc(Zn)were quantified utilizing a PerkinElmer 2000 inductively coupled plasma mass spectrometer.Principal component analysis was performed utilizing SPSS 25.0 to identify the distinctive characteristic elements of A.membranaceus.Additionally,systematic cluster analysis was conducted using these characteristic elements as variables to investigate the relationship between the primary inorganic elements and the geographical origin of A.membranaceus.[Results]17 inorganic elements were identified in A.membranaceus specimens collected from Gansu Province,with characteristic elements including Ba,Co,Fe,Ga,Mn,Zn,and Sn.The contents of inorganic elements in various sources of A.membranaceus exhibited significant variability and demonstrated distinct clustering characteristics.[Conclusions]A.membranaceus,originating from Gansu Province,exhibits a high content of inorganic elements.However,variations in ecological environments can lead to differences in the specific inorganic elements that are enriched.This study aims to provide a reference for the further development and application of A.membranaceus. 展开更多
关键词 ICP-MS ASTRAGALUS membranaceus GEOGRAPHICAL origin INORGANIC elements Principal component analysis Cluster analysis
暂未订购
WPPSI-III in Sudan:Validity,reliability,and confirmatory factor analysis in khartoum kindergarten and primary schools
2
作者 Rwaa Omer Ali Ahmed Salaheldin Farah Attallah Bakhiet +2 位作者 Ayman Mohamed Taha Abdelaziz Ahmed FadlAlMawla AbdulRadi Ismael Salamah Albursan 《Journal of Psychology in Africa》 2025年第4期431-439,共9页
The study aims to determine the validity and reliability of the Wechsler Preschool and Primary Scale of Intelligence–Third Edition(WPPSI-III)scores in a sample of kindergarten and lower primary pupils from Khartoum S... The study aims to determine the validity and reliability of the Wechsler Preschool and Primary Scale of Intelligence–Third Edition(WPPSI-III)scores in a sample of kindergarten and lower primary pupils from Khartoum State,Sudan.It also aims to examine whether test’s factor structure in this sample replicated that of the original WPPSI-III.The study sample consisted of 384 kindergarten and primary school children in Khartoum State(females=50%mean age=4.14,SD=1.37),selected using stratified random sampling across its seven localities:Khartoum,Jebel Awliya,Khartoum Bahri,East Nile,Omdurman,Ombada,Karari.For concurrent validation,the children additionally completed the Goodenough Draw-a-Man Test,and the Colored Progressive Matrices.WPPSI-III scores demonstrated high internal consistency across the subtest items.Confirmatory factor analysis indicators for total,verbal,and performance intelligence were all excellent.The scale also showed weak to strong score stability ranging from 0.25(weak)to 0.88(strong)based on the Spearman-Brown equation,0.25 to 0.75 based on the Guttman split-half method.The Cronbach’s alpha coefficient scores ranged from 0.54 to 0.93.The WPPSI-III and Goodenough Draw-a-Man Test scores concurrent validity scores were poor(0.05)to modest(0.31),and while those with the Colored Progressive Matrices test were poor(r=0.04–0.18).Thesefindings provide evidence to suggest that the WPPSI-III is appropriate for research use with kindergarten and lower primary school students in Khartoum State,Sudan. 展开更多
关键词 intelligence tests VALIDATION RELIABILITY primary schools kindergartens confirmatory factor analysis cognitive abilities WPPSI-III SUDAN
在线阅读 下载PDF
Nursing interventions’impact on cardiovascular complications after gastrointestinal surgery in intensive care unit:Risk factor analysis
3
作者 Ling Wang Peng Yang +1 位作者 Xue-Qing He Han Xia 《World Journal of Gastrointestinal Surgery》 2025年第8期133-141,共9页
BACKGROUND Cardiovascular(CV)complications are common in intensive care unit(ICU)patients after gastrointestinal surgery and are associated with increased mortality and prolonged hospital stay.The optimization of post... BACKGROUND Cardiovascular(CV)complications are common in intensive care unit(ICU)patients after gastrointestinal surgery and are associated with increased mortality and prolonged hospital stay.The optimization of postoperative nursing interventions,particularly pain management,is crucial for reducing such complications.AIM To investigate the effects of enhanced recovery nursing on CV complications after gastrointestinal surgery in ICU patients and associated risk factors.METHODS A retrospective analysis was conducted on 78 adult patients who underwent gastrointestinal surgery in the ICU of our hospital between February 2023 and September 2024.Among them,40 patients received standard care(control group),while 38 received enhanced recovery nursing(observation group).We compared the incidence of CV complications and nursing satisfaction between the two groups.Patients were divided into CV complication and non-complication groups based on complication occurrence,and logistic regression analysis was used to identify risk factors.RESULTS In the control and observation groups,the incidence of CV complications was 30.0%(12/40)and 18.4%(7/38),with a nursing satisfaction rate of 70.0%(28/40)and 92.1%(35/38),respectively.The postoperative pain score at 14 days was significantly lower in the observation group(0.27±0.15)compared to the control group(1.65±0.37),with all differences being statistically significant(P<0.05).Univariate analysis indicated significant differences in age,body mass index,hypertension,diabetes,smoking history,history of heart failure,and previous myocardial infarction(P<0.05).Multivariate logistic regression identified heart failure history,previous myocardial infarction,age,hypertension,and diabetes as independent risk factors,with odds ratios of 1.195,1.528,1.062,1.836,and 1.942,respectively(all P<0.05).CONCLUSION Implementing enhanced recovery nursing for ICU patients after gastrointestinal surgery is beneficial in reducing the incidence of CV complications and improving nursing satisfaction. 展开更多
关键词 Enhanced recovery nursing interventions Intensive care unit Gastrointestinal surgery Cardiovascular complications Risk factor analysis
暂未订购
Distribution of Traditional Chinese Medicine Syndromes and Syndrome Elements of Chronic Heart Failure Based on Network Analysis and Hierarchical Cluster Analysis
4
作者 ZHOU Yi HUANG Pinxian +1 位作者 LI Xiaoqian HE Jiancheng 《Chinese Medicine and Culture》 2025年第1期50-60,共11页
Traditional Chinese medicine(TCM)has played a significant role in the prevention and treatment of chronic heart failure(CHF).To study TCM diagnosis of CHF,a total of 278 Chinese clinical research articles on the study... Traditional Chinese medicine(TCM)has played a significant role in the prevention and treatment of chronic heart failure(CHF).To study TCM diagnosis of CHF,a total of 278 Chinese clinical research articles on the study of CHF syndromes in recent 40 years retrieved from Web of Science,Scopus,Pub Med,Embase,CNKI,Wanfang Data,Cq VIP,and Sino Med.According to cumulative frequency analysis,network analysis,and hierarchical cluster analysis,the study found the distribution of CHF syndromes was syndrome of qi deficiency with blood stasis,syndrome of qi and yin deficiency,syndrome of yang deficiency with water flooding,syndrome of heart blood stasis obstruction,syndrome of turbid phlegm,and syndrome of collapse due to primordial yang deficiency.The syndrome elements on location of illness were heart,kidney,lung,and spleen.The syndrome elements on nature of illness were qi deficiency,blood stasis,yang deficiency,yin deficiency,water retention,and turbid phlegm.These findings can provide reference to the research on diagnosis and treatment of CHF,and contribute to the study on syndrome standardization and objective research of TCM diagnosis. 展开更多
关键词 Chronic heart failure Traditional Chinese medicine Hierarchical cluster analysis Network analysis SYNDROME Syndrome differentiation Syndrome element
暂未订购
Research on the Construction of an Evaluation System for Innovation and Entrepreneurship Capabilities of Normal University Students Based on Factor Analysis Method
5
作者 Fang Liu Chi Li Lihua Jia 《Journal of Contemporary Educational Research》 2025年第8期320-327,共8页
Under the National Innovation-Driven Development Strategy,establishing a scientifically sound evaluation system for normal university students’innovation and entrepreneurship capabilities serves as a crucial foundati... Under the National Innovation-Driven Development Strategy,establishing a scientifically sound evaluation system for normal university students’innovation and entrepreneurship capabilities serves as a crucial foundation for optimizing innovation education models and enhancing teacher candidates’comprehensive competencies.Based on existing indicator frameworks,we designed a questionnaire and applied exploratory factor analysis(EFA)to screen indicators,reduce dimensionality,and analyze weighting.This process identified key metrics for evaluating pedagogical students’innovation capacities,ultimately constructing a targeted assessment system for normal university students.The study provides theoretical support for cultivating teacher trainees’innovative capabilities while contributing to the national innovation strategy implementation. 展开更多
关键词 factor analysis Innovation and entrepreneurship capability Indicator system Evaluation system UNIVERSITIES Normal university students
在线阅读 下载PDF
The enrichment of hazardous elements, rare earth elements and other inorganic constituents in a thick coal seam of the Lower Indus Basin, Pakistan
6
作者 Hassan Nasir Mangi Liqiang Ma +4 位作者 Robert B.Finkelman Detian Yan Jing Li Lara Sindhu Umar Ashraf 《International Journal of Coal Science & Technology》 2025年第3期291-312,共22页
The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objecti... The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objectively assess the mineralogical and geochemical characteristics of a thickest low-rank coal seam in the Lower Indus Basin southeastern Pakistan,and further investigate different controlling factors.The analytical results of major oxides,trace elements,and rare earth elements revealed that the weathering conditions were progressively variable and moderate.The sediment source,mainly of felsic and intermediate composition,was dominated by granitic rocks.The geochemical assessment reveals different depositional factors like marine environment influenced,while transitional and freshwater sediments influenced the center of the coal peat mire.Strontium,Zinc,and several hazardous trace elements,including Cu,Ni,Cr,and Co,have higher concentrations in these coals compared to world low-rank,U.S.,and Chinese coals.The relatively higher concentration of Sr in the thick coal seam in the Lower Indus Basin,compared to other coals seams in Pakistan and the enrichment of Sr was primarily controlled by the denudation of crystalline rocks and marine influx in the coal-basin.The REY distribution pattern showed that enrichment of medium and heavy rare earth elements is higher than light rare earth elements in the coal seam.The Gd distribution pattern in the coal seam demonstrated that strong positive anomalies had a good affinity with paleo-acidic water concentration in the study area.The higher concentration of Sr and other elements enables a better assessment understanding of the coal geochemical history. 展开更多
关键词 Coal geochemical analysis Trace elements STRONTIUM Hazardous elements Rare earth elements Lower-Indus Basin
在线阅读 下载PDF
Application of Detrital Apatite U-Pb Geochronology and Trace Elements for Provenance Analysis,Insights from a Study on the Yarlung River Sand
7
作者 Yufeng Du Guangwei Li +4 位作者 Danyang Liu Xianyan Wang Dongxu Cai Xiaolu Dong Qi Yu 《Journal of Earth Science》 SCIE CAS CSCD 2024年第4期1118-1129,共12页
Detrital U-bearing minerals(e.g.,zircon,apatite)U-Pb ages with specific trace-element geochemistry,are frequently used in provenance analyses.In this study,we focus on the Yarlung River drainage in South Xizang,charac... Detrital U-bearing minerals(e.g.,zircon,apatite)U-Pb ages with specific trace-element geochemistry,are frequently used in provenance analyses.In this study,we focus on the Yarlung River drainage in South Xizang,characterized by two distinct lithologic units:The Gangdese batholith to the north(mainly granitoids)and the Tethyan Himalaya(mainly sedimentary rocks)to the south,which plays a crucial role in the erosion of the Tibetan Plateau.To constrain the provenance of the Yarlung River Basin,we performed trace-element and U-Pb age analyses of detrital apatite from the river sands of the Yarlung River and its tributaries.Our findings indicate that the detrital apatite U-Pb age patterns of the north tributaries exhibit main peaks at approximately 40 and 60 Ma,consistent with the corresponding U-Pb age patterns of detrital zircon published.Further,their trace element casts fall mainly in the Type I granite region,also indicating the Gangdese arc-dominated source.However,those of the south tributaries(∼60–20 Ma)exhibit a different age distribution from the detrital zircon U-Pb groups(∼110–150,∼500,and 1100 Ma),suggesting that the detailed apatite U-Pb signals can provide excellent constraints on the provenance of igneous and metamorphic rock sources but less so for sedimentary rock sources.Combined with previous detrital zircon data in the study area,our detrital apatite information can highlight young metamorphic events from a complex background(i.e.,Niyang and Nianchu rivers),which offers additional constraints on the provenance of the Yarlung River Basin.Generally,a combination of geochemistry and geochronology of multi-detrital heavy minerals,such as zircon and apatite,can provide powerful tools for provenance analysis. 展开更多
关键词 APATITE detrital apatite U-Pb age trace elements provenance analysis Yarlung River Tibetan Plateau GEOCHRONOLOGY
原文传递
A State-Migration Particle Swarm Optimizer for Adaptive Latent Factor Analysis of High-Dimensional and Incomplete Data
8
作者 Jiufang Chen Kechen Liu +4 位作者 Xin Luo Ye Yuan Khaled Sedraoui Yusuf Al-Turki MengChu Zhou 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第11期2220-2235,共16页
High-dimensional and incomplete(HDI) matrices are primarily generated in all kinds of big-data-related practical applications. A latent factor analysis(LFA) model is capable of conducting efficient representation lear... High-dimensional and incomplete(HDI) matrices are primarily generated in all kinds of big-data-related practical applications. A latent factor analysis(LFA) model is capable of conducting efficient representation learning to an HDI matrix,whose hyper-parameter adaptation can be implemented through a particle swarm optimizer(PSO) to meet scalable requirements.However, conventional PSO is limited by its premature issues,which leads to the accuracy loss of a resultant LFA model. To address this thorny issue, this study merges the information of each particle's state migration into its evolution process following the principle of a generalized momentum method for improving its search ability, thereby building a state-migration particle swarm optimizer(SPSO), whose theoretical convergence is rigorously proved in this study. It is then incorporated into an LFA model for implementing efficient hyper-parameter adaptation without accuracy loss. Experiments on six HDI matrices indicate that an SPSO-incorporated LFA model outperforms state-of-the-art LFA models in terms of prediction accuracy for missing data of an HDI matrix with competitive computational efficiency.Hence, SPSO's use ensures efficient and reliable hyper-parameter adaptation in an LFA model, thus ensuring practicality and accurate representation learning for HDI matrices. 展开更多
关键词 Data science generalized momentum high-dimensional and incomplete(HDI)data hyper-parameter adaptation latent factor analysis(LFA) particle swarm optimization(PSO)
在线阅读 下载PDF
Simultaneous Determination of Rare Earth Elements by Dual-System Iterative Target Transformation Factor Analysis
9
作者 Liu, Delong Yang, Yansheng 《Journal of Rare Earths》 SCIE EI CAS CSCD 1999年第2期68-71,共4页
Dualcolor systems were used to reduce the collinearity of multicomponent spectra, which is described by the angles between spectra vectors. Combined with iterative target transformation factor analysis, single rare ea... Dualcolor systems were used to reduce the collinearity of multicomponent spectra, which is described by the angles between spectra vectors. Combined with iterative target transformation factor analysis, single rare earth element was determined in its mixture. The calculated results show that the average angle between rare earth spectra in one color system(trichloroarsenazorare earths, pH 34) is 45, and that in two color systems(trichloroarsenazorare earths, pH 34, 14) is 215. This technique makes it easy to select the real number of the components in mixtures, and the determination results show dualcolor system method is an effective technique in rare earth mixture analysis. 展开更多
关键词 Rare earths Multicomponent analysis Iterative target transformation factor analysis
在线阅读 下载PDF
An <i>in silico</i>Analysis of Upstream Regulatory Modules (URMs) of Tapetum Specific Genes to Identify Regulatory <i>cis</i>-Elements and Transcription Factors 被引量:1
10
作者 Preeti Apurve Sharma Pradeep Kumar Burma 《American Journal of Molecular Biology》 2018年第1期13-25,共13页
The present work presents an iin silicoi analysis of Upstream Regulatory Modules (URMs) of genes expressed in tapetum specific manner in dicotyledon and monocotyledon plants. In the current analysis, we identified sev... The present work presents an iin silicoi analysis of Upstream Regulatory Modules (URMs) of genes expressed in tapetum specific manner in dicotyledon and monocotyledon plants. In the current analysis, we identified several motifs conserved in these URMs of which ten were observed to be part of known icisi-elements using tools and databases like MEME, PLACE, MAST and TFSEARCH. We also identified that binding sites for two transcription factors, DOF and WRKY71 were found to be present in majority of the URMs. 展开更多
关键词 TAPETUM Specific Promoter CIS-elements Transcription factors
暂未订购
Assessment of trace elements distribution and sources from snowpits in the Lambert Glacier region,coastal East Antarctica
11
作者 Yalalt Nyamgerel Soon Do Hur +3 位作者 Tseren-Ochir Soyol-Erdene Cunde Xiao Hyejung Jung Jeonghoon Lee 《Geoscience Frontiers》 2025年第3期425-437,共13页
The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,partic... The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,particularly those evaluating multiple metals across several snowpits,making interpretation challenging.This study investigates the distributions and sources of trace elements-including Cd,Ba,Pb,U,Bi,V,Mn,Fe,Cu,Zn,and As-across four snowpits in the Lambert Glacier Basin,East Antarctica.The trace elements exhibit site-,element-,and season-dependent variations,with higher concentrations observed at inland sites.In contrast,δ^(18)O and ion concentrations decrease with increasing distance from the coast and elevation,underscoring the influence of marine emissions.Crustal sources primarily contributed to Ba,U,V,Mn,and Fe,while non-crustal sources predominantly contributed to Cd,Bi,Zn,Pb,Cu,and As.Positive matrix factorization(PMF)analysis indicates that trace element concentrations in Pits 2 and 3 are influenced by both crustal and non-crustal sources,while Pit 4 reflects a mixed-source influence.Pit 1(coastal site)also indicates the mixed sources with influence of a highly dynamic marine climate and environment.The PMF results reveal similarities in emission sources and atmospheric transport patterns across the snowpits,facilitating a more comprehensive interpretation of longer ice core records.Overall,this study provides valuable insights into trace element distributions and enhances our understanding of past environmental and climatic conditions. 展开更多
关键词 Trace elements Spatial variation ANTARCTICA Lambert Glacier Basin Positive matrix factorization
暂未订购
Identification of the Nonlinear Distributions of Elements with Multifractal: A Case Study of the Er’renshan Ore Field, NW China
12
作者 GONG Qiuli LIU Yanpeng 《Acta Geologica Sinica(English Edition)》 2025年第5期1509-1526,共18页
Geochemical surveys are essential for understanding the spatial distribution of ore-forming elements.However,these surveys often involve compositional data,the weight concentrations,which do not meet the requirements ... Geochemical surveys are essential for understanding the spatial distribution of ore-forming elements.However,these surveys often involve compositional data,the weight concentrations,which do not meet the requirements of statistical methods due to the closure effect.In this study,we applied an integrated approach combining compositional data,multifractal,and multivariate statistical analyses to identify the nonlinear complexity of the spatial distributions of elemental concentrations in the Er’renshan ore field.Initially,the raw concentrations were transformed into log-ratios following the principles of composition data theory to alleviate the impact of the closure effect.Multifractal analysis was then conducted to characterise the nonlinear complexity of the concentration distributions.Furthermore,principal component analysis(PCA)and factor analysis(FA)were applied to identify spurious correlations and the potential factors controlling the distribution patterns.The results demonstrate that:a)the raw data are biased,while the log-ratio data are unbiased and more reliable;b)the spatial distributions of elemental concentrations exhibit nonlinear complexity;and c)the elemental distribution in the study area is largely controlled by structural factors. 展开更多
关键词 nonlinear complexity compositional data FRACTAL multivariate statistical analysis element distribution
在线阅读 下载PDF
Study on Trace Elements in Rehmannia glutinosa Libosch. by Principal Component Analysis and Clustering Analysis
13
作者 申明金 陈丽 曹洪斌 《Agricultural Science & Technology》 CAS 2013年第12期1764-1768,共5页
[Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering anal... [Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering analysis of R. glutinosa medicinal materials from different sources were conducted with contents of six trace elements as indices. [Result] The principal component analysis could comprehen- sively evaluate the quality of R. glutinosa samples with objective results which was consistent with the results of clustering analysis. [Conclusion] Principal component analysis and clustering analysis methods can be used for the quality evaluation of Chinese medicinal materials with multiple indices. 展开更多
关键词 Rehmannia glutinosa Libosch. (Radix Rehmanniae) Trace elements Principal component analysis Clustering analysis
在线阅读 下载PDF
Determination of Harmful Elements and Analysis of Pollution Level in Lysimachia christinae
14
作者 Li WAN Ya GUO +2 位作者 Qin XIANG Qi XIAO Wenwu YANG 《Medicinal Plant》 CAS 2022年第5期31-33,共3页
[Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass... [Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass spectrometry and analyzed by single index and comprehensive index.[Results]The seven heavy metal elements showed good linearity in their respective concentration ranges.The recoveries of the samples were 84.5%-109.5%,and the RSD values were 2.30%-5.10%.Comparing the measured results of heavy metal elements with the limit values stipulated in the 2020 edition of the Chinese Pharmacopoeia and other standards,the Cr element in 19 batches of samples exceeded the standard,and the Zn element in 7 batches of samples exceeded the standard.The exceeding rates were 100.0%and 36.8%,respectively;the content of other heavy metal elements did not exceed the standard.The order of individual index from large to small was Cr,Zn,Cd,Hg,Cu,As,and Pb,and the average comprehensive pollution level was mild pollution and above.[Conclusions]L.christinae was mainly polluted by Cr,followed by Zn;this study can provide basic data for drafting of the limit standard for heavy metal elements in L.christinae. 展开更多
关键词 Lysimachia christinae Heavy metals elements Harmful elements ICP-MS Microwave digestion Single factor index method Comprehensive index method Pollution level analysis Quality control
暂未订购
Characterization of dissolved organic matter in urban sewage using excitation emission matrix fluorescence spectroscopy and parallel factor analysis 被引量:41
15
作者 Weidong Guo Jing Xu +3 位作者 Jiangping Wang Yingrou Wen Jianfu Zhuo Yuchao Yan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第11期1728-1734,共7页
Wastewater dissolved organic matter (DOM) from different processing stages of a sewage treatment plant in Xiamen was characterized using fluorescence and absorption spectroscopy. Parallel factor analysis modeling of... Wastewater dissolved organic matter (DOM) from different processing stages of a sewage treatment plant in Xiamen was characterized using fluorescence and absorption spectroscopy. Parallel factor analysis modeling of excitation-emission matrix spectra revealed five fluorescent components occurring in sewage DOM: one protein-like (C1), three humic-like (C2, C4 and C5) and one xenobiotic-like (C3) components. During the aerated grit chamber and primary sedimentation tank stage, there was only a slight decrease in fluorescence intensity and the absorption coefficient at 350 nm (a 350 ). During the second aeration stage, high concentration of protein-like and short-wavelength-excited humic-like components were significantly degraded accompanied by significant loss of DOC (80%) and a 350 (30%), indicating that C1 and C2 were the dominant constituents of sewage DOM. As a result, long-wavelength- excited C4 and C5 became the dominant humic-like components and the DOM molecular size inferred from the variation of spectral slope S (300–650 nm) and specific absorption (a 280 /DOC) increased. Combination use of F max of C1 and the ratio of C1/C5, or a 350 may provide a quantitative indication for the relative amount of raw or treated sewage in aquatic environment. 展开更多
关键词 dissolved organic matter SEWAGE fluorescence EEM parallel factor analysis
原文传递
Finite element analysis of elasto-plastic plate bending problems using transition rectangular plate elements 被引量:4
16
作者 B. Kanber O. Yavuz Bozkurt 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2006年第4期355-365,共11页
In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based... In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based on a practical rule. The transition plate elements are all quadrilateral and can be used to obtain efficient finite element models using minimum number of elements. The mesh convergence rates of the models including the transition elements are compared with the regular element models. To verify the developed elements, simple tests are demonstrated and various elasto-plastic problems are solved. Their results are compared with ANSYS results. 展开更多
关键词 Finite element method Transition plate elements Elasto-plastic analysis. Plate bending problems
在线阅读 下载PDF
Application of 1D/3D finite elements coupling for structural nonlinear analysis 被引量:13
17
作者 岳健广 A.Fafitis +1 位作者 钱江 雷拓 《Journal of Central South University》 SCIE EI CAS 2011年第3期889-897,共9页
An element coupling model (ECM) method was proposed to simulate the global behavior and local damage of a structure.In order to reflect the local damage and improve the computational efficiency,three-dimensional (3D) ... An element coupling model (ECM) method was proposed to simulate the global behavior and local damage of a structure.In order to reflect the local damage and improve the computational efficiency,three-dimensional (3D) solid elements and one-dimensional (1D) beam element were coupled by the multi-point constraint equations.A reduced scale 1?8 model test was simulated by the ECM and a full three dimensional model (3DM) contrastively.The results show that the global behavior and local damages of ECM agree well with the test and 3DM.It is indicated that the proposed method can be used in the structural nonlinear analysis accurately and efficiently. 展开更多
关键词 elements coupling model global behavior local damage multi-point constraint equations nonlinear analysis
在线阅读 下载PDF
Analysis of metallic elements dissolution in the Astragalus at different decocting time by using LIBS technique 被引量:5
18
作者 Weiwei HAN Maogen SU +5 位作者 Duixiong SUN Yaopeng YIN Yupeng WANG Chunli GAO Fuchun YANG Yanbiao FU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第8期137-143,共7页
Astragalus is an important traditional Chinese herb that has therapeutic potential in the treatment of diseases. In this study, the dissolution of metallic elements during the material decoction process was investigat... Astragalus is an important traditional Chinese herb that has therapeutic potential in the treatment of diseases. In this study, the dissolution of metallic elements during the material decoction process was investigated using laser-induced breakdown spectroscopy(LIBS). The Ca, Mg, Al, and Fe in the drug residues, liquid, and vapor were selected for the study of the transfer of elements after different decocting times. It was found that the intensities of the spectral lines for these elements in the drug liquid increased with increasing decocting times.The contrast trend was observed in the residues and only calcium was detected in the vapor.Furthermore, the relative mass concentrations of Ca, Mg, Al, and Fe in the liquid were quantitatively determined by a combination of the standard addition method and calibrationfree-LIBS method by adding the standard concentration solution of Cu and Cd elements into the drug liquids, it can be found that the maximum error between Cd concentration calculated by internal CF-LIBS and the standard is within 10%. This provides a new method of achieving the on-line monitoring and analysis of metallic elements in the production of traditional Chinese medicines. 展开更多
关键词 ASTRAGALUS DECOCTION LASER-INDUCED breakdown spectroscopy metallic elements DISSOLUTION quantitative analysis
暂未订购
In situ Analysis of Major Elements, Trace Elements and Sr Isotopic Compositions of Apatite from the Granite in the Chengchao Skarn-Type Fe Deposit, Edong Ore District: Implications for Petrogenesis and Mineralization 被引量:2
19
作者 Zhenghan Li Dengfei Duan +2 位作者 Shaoyong Jiang Ying Ma Hongwei Yuan 《Journal of Earth Science》 SCIE CAS CSCD 2018年第2期295-306,共12页
Major elements, trace elements and Sr isotopic compositions of apatite from the granite in the Chengchao skarn-type Fe deposit of Edong ore district of Middle-Lower Yangtze River metallogenic belt were measured using ... Major elements, trace elements and Sr isotopic compositions of apatite from the granite in the Chengchao skarn-type Fe deposit of Edong ore district of Middle-Lower Yangtze River metallogenic belt were measured using EMPA (electron microprobe), LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometer) and LA-MC (multicollector)-ICP-MS methods in order to reveal the petroge- netic and metallogenic significance of the skarn-type iron deposits. The results show that the apatite in Chengchao granite is fluorapatite, which displays slight variation in major elements. The REE distribution pattern of the apatite is similar to that of the whole rocks, with strong negative Eu anomaly and low Sr/Y ratio. The concentration of Mn in apatite is low (140 ppm-591 ppm) and the Sr isotopic composition shows a limited variation from 0.706 9 to 0.708 2. The high oxygen fugacity of the Chengchao granite, implied by the low Mn content in apatite, is possibly attributed to contamination of the gypsum from sedimentary rock strata, which has long been thought to be an important factor that controls the Fe mineralization in the Middle-Lower Yangtze River metallogenic bell This study also proves that the Eu/Eu* value and Sr/Y ra- tio in apatite can be effectively used to identify the adakitie affinity. The in situ Sr isotope analysis of apatite is in consistent with the bulk rock analysis, which indicates that the apatite Sr isotope can represent the ini- tial Sr isotopic compositions of the magma. The Sr isotope and negative Eu anomaly in apatite imply that the Chengchao granite is likely sourced from crust-mantle mixed materials. 展开更多
关键词 APATITE in situ analysis Sr isotopes trace elements adakite identification oxygen fugacity.
原文传递
Modifying the Autism Spectrum Rating Scale(6–18 years)to a Chinese Context:An Exploratory Factor Analysis 被引量:10
20
作者 Hao Zhou Lili Zhang +10 位作者 Xuerong Luo Lijie Wu Xiaobing Zou Kun Xia Yimin Wang Xiu Xu Xiaoling Ge Yong-Hui Jiang Eric Fombonne Weili Yan Yi Wang 《Neuroscience Bulletin》 SCIE CAS CSCD 2017年第2期175-182,共8页
The purpose of this study was to explore the psychometric properties of the Chinese version of the autism spectrum rating scale(ASRS). We recruited 1,625community-based children and 211 autism spectrum disorder(ASD... The purpose of this study was to explore the psychometric properties of the Chinese version of the autism spectrum rating scale(ASRS). We recruited 1,625community-based children and 211 autism spectrum disorder(ASD) cases from 4 sites, and the parents of all participants completed the Chinese version of the ASRS. A robust weighted least squares means and variance adjusted estimator was used for exploratory factor analysis. The3-factor structure included 59 items suitable for the current sample. The item reliability for the modi?ed Chinese version of the ASRS(MC-ASRS) was excellent. Moreover,with 60 as the cut-off point, receiver operating characteristic analysis showed that the MC-ASRS had excellent discriminate validity, comparable to that of the unmodi?ed Chinese version(UC-ASRS), with area under the curve values of 0.952(95% CI: 0.936–0.967) and 0.948(95% CI:0.930–0.965), respectively. Meanwhile, the con?rm factor analysis revealed that MC-ASRS had a better construct validity than UC-ASRS based on the above factor solution in another children sample. In conclusion, the MC-ASRS shows better ef?cacy in epidemiological screening for ASD in Chinese children. 展开更多
关键词 Autism spectrum disorder Screening Epidemiology Exploratory factor analysis Children
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部