期刊文献+
共找到23篇文章
< 1 2 >
每页显示 20 50 100
Scaling behavior of nucleotide cluster in DNA sequences
1
作者 CHENG Jun TONG Zi-shuang ZHANG Lin-xi 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2007年第5期359-364,共6页
In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the sc... In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the scaling behavior of P ( S ) ∝ e ?αS, where S represents nucleotide cluster size. The cluster-size distribution P(S1+S2) with the total size of sequential C-G cluster and A-T cluster S1+S2 were also studied. P(S1+S2) follows exponential decay. There does not exist the case of large C-G cluster following large A-T cluster or large A-T cluster following large C-G cluster. We also discuss the relatively random walk length function L(n) and the local compositional complexity of nucleotide sequences based on a new model. These investigations may provide some insight into nucleotide cluster of DNA sequence. 展开更多
关键词 Nucleotide cluster DNA sequences scaling behavior
下载PDF
Scaling Behaviors of Polymers on Lipid Membranes:Coupling of Polymer Chain Dynamics and Surface Thermal Fluctuations
2
作者 Zi-Ren Chen Wu Zhou Lei Shen 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2023年第3期459-464,I0010,共7页
Despite extensive researches on the motion of polymer chains on lipid membranes,the effect of membrane fluctuations on polymer chain dynamics remains poorly understood.Here we report single molecule tracking experimen... Despite extensive researches on the motion of polymer chains on lipid membranes,the effect of membrane fluctuations on polymer chain dynamics remains poorly understood.Here we report single molecule tracking experiments that allow for comparable measurements of polymer chain diffusion dynamics on nanotubular and planar phospholipid membranes.We observe a super-diffusion behavior and no apparent chain-length-dependent mobility of polymer chains on nanotubular membranes,while a Brownian motion and apparent chain-lengthdependent mobility of polymer chains on planar membranes.We suggest the super-diffusion nature of polymer chains may be due to the thermal-fluctuations of lipid nanotubes,which can be described from a statistical thermodynamic phenomenon coupling of polymer chain dynamics and surface thermal fluctuations.We suggest that the existence of surface environment fluctuations should influence the dynamics of the adsorbed polymer chains.This study provides previously uncharacterized insights into polymer diffusion dynamics on thermal-fluctuating flexible surfaces,which is essential to understanding the effect of environment fluctuations on polymer chain behaviors. 展开更多
关键词 Polymer diffusion Lipid membrane scaling behavior
原文传递
Evidence for the Reliability and Validity of the Arabic Version of the Student Risk Screening Scale for Internalizing and Externalizing Behaviors (SRSS-IE)
3
作者 Sumayah A. Alrubayie Keetam D. F. Alkahtani 《Journal of Behavioral and Brain Science》 2024年第1期32-45,共14页
School-based universal screening for behavioral/emotional risk is a necessary first step to providing services in an educational setting for students with emotional and behavioral disorders (EBDs). Psychometric proper... School-based universal screening for behavioral/emotional risk is a necessary first step to providing services in an educational setting for students with emotional and behavioral disorders (EBDs). Psychometric properties are critical to making decisions about choosing a screening instrument. The purpose of the present study was to examine the psychometric properties of the student risk screening scale for internalizing and externalizing behaviors (SRSS-IE). Participants included 3145 students and their teachers. Item-level analyses of the current sample supported the retention of all items. The internal consistency of the SRSS items ranged from 0.83 to 0.85. Convergent validity between the SRSS-IE and a well-established screening tool, the strength and difficulties questionnaire (SDQ), was found for the total score (r = 0.70). Additionally, the results of this study demonstrate strong social validity, suggesting the SRSS-IE to be a useful and functional screening tool. We conclude that the SRSS-IE is a valid and reliable instrument for assessing the level of emotional and behavioral difficulties among elementary students. 展开更多
关键词 The Student Risk Screening Scale for Internalizing and Externalizing behaviors (SRSS-IE) Strength and Difficulties Questionnaire (SDQ) Emotional and behavioral Difficulties Screening Tools Systematic Screening
下载PDF
Scaling behavior of magnitude clusters in aftershock sequence:An example of the Wenchuan Earthquake,China 被引量:4
4
作者 ZHANG Bin SHI Kai +3 位作者 LIU ChunQiong YAO LingKan DI BaoFeng AI NanShan 《Science China Earth Sciences》 SCIE EI CAS 2012年第3期507-512,共6页
The Gutenberg-Richter and Omori Laws, which are generally used to characterize the temporal distribution of aftershock, failed to reflect the statistic properties of climatic outbreak of aftershock energy. Based on a ... The Gutenberg-Richter and Omori Laws, which are generally used to characterize the temporal distribution of aftershock, failed to reflect the statistic properties of climatic outbreak of aftershock energy. Based on a new concept of magnitude clusters describing the fluctuation of aftershock energy release of the Wenchuan Earthquake, we discovered that the pattern of the continuous high-magnitude aftershock follows a power-law rather than a non-Poisson distribution. This suggests that the after-shocks with high magnitudes are statistically clustered. We then divided the aftershock sequences into three sections and demonstrated that though the probability of strong outbreaks decreased with time, there exists a high possibility of the occurrence of isolated high-magnitude aftershocks in the future. Based on self-organized criticality theory, the mechanisms of the power-law pattern of magnitude clusters are discussed. This discovery may be used to guide future aftershock predication and the associated post-disaster reconstruction. 展开更多
关键词 scaling behavior magnitude clusters aftershock sequence Wenchuan Earthquake
原文传递
The scaling behavior of the second virial coefficient of linear and ring polymer
5
作者 Bing Li Zhaoyan Sun +1 位作者 Lijia An Zhen-Gang Wang 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第5期619-623,共5页
The scaling behavior of the second virial coefficient of ring polymers at the theta temperature of the corresponding linear polymer(θ_L) is investigated by off-lattice Monte Carlo simulations. The effects of the solv... The scaling behavior of the second virial coefficient of ring polymers at the theta temperature of the corresponding linear polymer(θ_L) is investigated by off-lattice Monte Carlo simulations. The effects of the solvents are modeled by pairwise interaction between polymer monomers in this approach. Using the umbrella sampling, we calculate the effective potential U(r) between two ring polymers as well as the second virial coefficient A_2 of ring polymers at θ_L, which results from a combination of 3-body interactions and topological constraints. The trend in the strength of the effective potential with respect to chain length shows a non-monotonic behavior, differently from that caused only by topological constraints. Our simulation suggests that there are three regimes about the scaling behavior of A_2 of ring polymers at θ_L: 3-body interactions dominating regime, the crossover regime, and the topological constraints dominating regime. 展开更多
关键词 second virial coefficient topological constraints 3-body interactions theta temperature scaling behavior
原文传递
Scaling Behavior of Bulk Freight Rate Volatility Before and After Noise Reduction
6
作者 代思宇 陈飞儿 +1 位作者 曾亚东 曾鑫 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第6期655-661,共7页
Analysis of freight rate volatility characteristics is a hot topic after year 2008 due to the effect of financial crisis in marine transportation.In this paper,we analyze the bulk freight rate index by detrended fluct... Analysis of freight rate volatility characteristics is a hot topic after year 2008 due to the effect of financial crisis in marine transportation.In this paper,we analyze the bulk freight rate index by detrended fluctuation analysis(DFA) method and discover the scaling behavior.Switching points(SPs),as the indicators of scaling behavior,can be eliminated after Vondr′ak noise reduction technique.Therefore,we conclude that highfrequency noise is the cause of SP. 展开更多
关键词 bulk freight rate noise reduction detrended fluctuation analysis(DFA) Vondr′ak filtering scaling behavior
原文传递
Effect of long-range correlation on scaling behavior of normalized factorial moments for the first-order phase transition
7
作者 李光磊 杨纯斌 《Chinese Physics C》 SCIE CAS CSCD 2016年第1期55-59,共5页
Within the framework of Ginzburg Landau theory, the effect of multiplicity correlation between the dynamical multiplicity fluctuations is analyzed for a first-order phase ~ransition from quark gluon plasma to hadrons.... Within the framework of Ginzburg Landau theory, the effect of multiplicity correlation between the dynamical multiplicity fluctuations is analyzed for a first-order phase ~ransition from quark gluon plasma to hadrons. Normalized factorial correlators are used to study the correlated dynamical fluctuations. A scaling behavior is found among the factorial correlators, and an approximate universal exponent, which is weakly dependent on the details of the phase transition, is obtained. 展开更多
关键词 factorial correlators Ginzburg Landau model scaling behavior
原文传递
Scaling dependence of memory windows and different carrier charging behaviors in Si nanocrystal nonvolatile memory devices
8
作者 于杰 陈坤基 +5 位作者 马忠元 张鑫鑫 江小帆 吴仰晴 黄信凡 Shunri Oda 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第9期518-522,共5页
Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal(Si-NC) nonvolatile memory(NVM) devices for its scaling down limit.In this work,we... Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal(Si-NC) nonvolatile memory(NVM) devices for its scaling down limit.In this work,we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor(CMOS) technology.It is found that the memory windows of eight kinds of test key cells are almost the same of about1.64 V @ ±7 V/1 ms,which are independent of the gate area,but mainly determined by the average size(12 nm) and areal density(1.8×10^(11)/cm^2) of Si-NCs.The program/erase(P/E) speed characteristics are almost independent of gate widths and lengths.However,the erase speed is faster than the program speed of test key cells,which is due to the different charging behaviors between electrons and holes during the operation processes.Furthermore,the data retention characteristic is also independent of the gate area.Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration. 展开更多
关键词 silicon nanocrystals nonvolatile memory scaling dependence different charging behaviors
下载PDF
Efficacy of Children Neuropsychological and Behavioral Scale in Screening for Autism Spectrum Disorders through a Combination of Developmental Surveillance
9
作者 Jin-hui LI Jin-zhu ZHAO +9 位作者 Li HUA Xiao-lin HU Li-na TANG Ting YANG Tian-yi HE Chen HU Xiao-qun YU Ting-ting XIONG Dan-dan WU Yan HAO 《Current Medical Science》 SCIE CAS 2023年第3期592-601,共10页
Objective This study aimed to explore the clinical value of Children Neuropsychological and Behavioral Scale-Revision 2016(CNBS-R2016)for Autism Spectrum Disorder(ASD)screening in the presence of developmental surveil... Objective This study aimed to explore the clinical value of Children Neuropsychological and Behavioral Scale-Revision 2016(CNBS-R2016)for Autism Spectrum Disorder(ASD)screening in the presence of developmental surveillance.Methods All participants were evaluated by the CNBS-R2016 and Gesell Developmental Schedules(GDS).Spearman’s correlation coefficients and Kappa values were obtained.Taking GDS as a reference assessment,the performance of the CNBS-R2016 for detecting the developmental delays of children with ASD was analyzed with receiver operating characteristic(ROC)curves.The efficacy of the CNBS-R2016 to screen for ASD was explored by comparing Communication Warning Behavior with Autism Diagnostic Observation Schedule,Second Edition(ADOS-2).Results In total,150 children aged 12–42 months with ASD were enrolled.The developmental quotients of the CNBS-R2016 were correlated with those of the GDS(r=0.62–0.94).The CNBS-R2016 and GDS had good diagnostic agreement for developmental delays(Kappa=0.73–0.89),except for Fine Motor.There was a significant difference between the proportions of Fine Motor,delays detected by the CNBS-R2016 and GDS(86.0%vs.77.3%).With GDS as a standard,the areas under the ROC curves of the CNBS-R2016 were above 0.95 for all the domains except Fine Motor,which was 0.70.In addition,the positive rate of ASD was 100.0%and 93.5%when the cut-off points of 7 and 12 in the Communication Warning Behavior subscale were used,respectively.Conclusion The CNBS-R2016 performed well in developmental assessment and screening for children with ASD,especially by Communication Warning Behaviors subscale.Therefore,the CNBS-R2016 is worthy of clinical application in children with ASD in China. 展开更多
关键词 autism spectrum disorder Children Neuropsychological and behavioral Scale screening for autism spectrum disorder developmental assessment
下载PDF
Extensive numerical simulations on competitive growth between the Edwards–Wilkinson and Kardar–Parisi–Zhang universality classes
10
作者 余成志 刘潇 +1 位作者 唐军 夏辉 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期298-307,共10页
Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and K... Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and Kardar–Parisi–Zhang(KPZ) universality classes, respectively. The linear growth systems include the EW equation and the model of random deposition with surface relaxation(RDSR), the nonlinear growth systems involve the KPZ equation and typical discrete models including ballistic deposition(BD), etching, and restricted solid on solid(RSOS). The scaling exponents are obtained in both the(1 + 1)-and(2 + 1)-dimensional competitive growth with the nonlinear growth probability p and the linear proportion 1-p. Our results show that, when p changes from 0 to 1, there exist non-trivial crossover effects from EW to KPZ universality classes based on different competitive growth rules. Furthermore, the growth rate and the porosity are also estimated within various linear and nonlinear growths of cooperation and competition. 展开更多
关键词 competitive growth scaling behavior discrete growth model Kardar–Parisi–Zhang universality class
下载PDF
Developing the information-seeking behavior scale for undergraduates 被引量:4
11
作者 Dehua HU Dan CHE 《Chinese Journal of Library and Information Science》 2013年第1期78-96,共19页
Purpose: The aim of this paper is to develop a standardized and reliable measurement tool for assessing information-seeking behavior of undergraduate students.Design/methodology/approach: Based on information literacy... Purpose: The aim of this paper is to develop a standardized and reliable measurement tool for assessing information-seeking behavior of undergraduate students.Design/methodology/approach: Based on information literacy and information-seeking behavior theories, expert advice and students' interview, items of undergraduates' informationseeking behavior indicators were selected. With the analysis of homogeneity reliability, item analysis and factor analysis, this study constructs an assessment system to evaluate reliability and validity of the scale.Findings: The information-seeking behavior scale for undergraduates has divided undergraduates' information-seeking behavior into seven dimensions, which include 46 items. The reliability analysis of Cronbach's α was 0.910, and the coefficient of split-half reliability was0.817. The results of factor analysis showed that Kaiser-Meyer-Olkin(KMO) was 0.864,which indicates 55.536% of the total variation could be explained by the above seven dimensions.Research limitations: Due to a small sample size and limited sample distribution, further research need be conducted in an expanded sample size in order to explore the application scope of this evaluation system; in addition, the stability of the scale also need be confirmed.Practical implications: The paper sets up an information-seeking behavior evaluation system for undergraduates and explores the characteristics of their information-seeking behavior.This study provides guidance for the development of future information literacy education and the improvement of the information literacy level of undergraduates.Originality/value: An information-seeking behavior scale for undergraduates has been developed, which comprehensively covers information need, information source, information evaluation, information retrieval, information management, information utilization and information morality. The scale is proved to have good reliability, validity, popularity anddiscrimination that it is qualified to be an assessment tool of information-seeking behavior for Chinese undergraduates. 展开更多
关键词 Scale for information seeking behavior Indicators for information education Information literacy framework Information Literacy Competency Standards for Higher Education
下载PDF
On the Cosmic Evolution of the Quantum Vacuum Using Two Variable G Models and Winterberg’s Thesis
12
作者 Christopher Pilot 《Journal of High Energy Physics, Gravitation and Cosmology》 2023年第4期1134-1160,共27页
We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckion... We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckions. These material particles interact indirectly, and have very strong restoring forces keeping them a finite distance apart from each other within their respective species. Because of their mass compensating effect, the vacuum appears massless, charge-less, without pressure, net energy density or entropy. In addition, we consider two varying G models, where G, is Newton’s constant, and G<sup>-1</sup>, increases with an increase in cosmological time. We argue that there are at least two competing models for the quantum vacuum within such a framework. The first follows a strict extension of Winterberg’s model. This leads to nonsensible results, if G increases, going back in cosmological time, as the length scale inherent in such a model will not scale properly. The second model introduces a different length scale, which does scale properly, but keeps the mass of the Planck particle as, ± the Planck mass. Moreover we establish a connection between ordinary matter, dark matter, and dark energy, where all three mass densities within the Friedman equation must be interpreted as residual vacuum energies, which only surface, once aggregate matter has formed, at relatively low CMB temperatures. The symmetry of the vacuum will be shown to be broken, because of the different scaling laws, beginning with the formation of elementary particles. Much like waves on an ocean where positive and negative planckion mass densities effectively cancel each other out and form a zero vacuum energy density/zero vacuum pressure surface, these positive mass densities are very small perturbations (anomalies) about the mean. This greatly alleviates, i.e., minimizes the cosmological constant problem, a long standing problem associated with the vacuum. 展开更多
关键词 Winterberg Model Planck Particles Positive and Negative Mass Planck Particles Planckions Quantum Vacuum Space as a Superfluid/Supersolid Extended Models for Space Cosmological Constant Higgs Field as a Composite Particle Higgs Boson Inherent Length Scale for the Vacuum Dark Energy Cosmological scaling behavior for the Quantum Vacuum Variable G Models Extended Gravity Newton’s Constant as an Order Parameter High Energy behavior for the Vacuum
下载PDF
Analysing the structure of the optical path length of a supersonic mixing layer by using wavelet methods 被引量:1
13
作者 高穹 易仕和 +2 位作者 姜宗福 赵玉新 谢文科 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期344-351,共8页
The nano-particle-based planar laser scattering (NPLS) technique is used to measure the density distribution in the supersonic mixing layer of the convective Mach number 0.12, and the optical path difference (OPL)... The nano-particle-based planar laser scattering (NPLS) technique is used to measure the density distribution in the supersonic mixing layer of the convective Mach number 0.12, and the optical path difference (OPL), which is quite crucial for the study of aero-optics, is obtained by post processing. Based on the high spatiotemporal resolutions of the NPLS, the structure of the OPL is ana]ysed using wavelet methods. The coherent structures of the OPL are extracted using three methods, including the methods of thresholding the coefficients of the orthogonal wavelet transform and the wavelet packet transform, and preserving a number of wavelet packet coefficients with the largest amplitudes determined by the entropy dimension. Their performances are compared, and the method using the wavelet packet is the best. Based on the viewpoint of multifractals, we study the OPL by the wavelet transform maxima method (WTMM), and the result indicates that its scaling behaviour is evident. 展开更多
关键词 optical path difference AERO-OPTICS supersonic mixing layer WAVELET coherent struc-tures scaling behavior
下载PDF
INVESTIGATION OF STRUCTURE AND PROPERTIES FOR POLYMER SYSTEMS BASED ON DYNAMIC RHEOLOGICAL APPROACHES 被引量:6
14
作者 郑强 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2005年第4期341-354,共14页
The dynamic rheological measurements have been a preferred approach to the characterization of the structure and properties for multi-component or multi-phase polymer systems,due to its sensitive response to changes o... The dynamic rheological measurements have been a preferred approach to the characterization of the structure and properties for multi-component or multi-phase polymer systems,due to its sensitive response to changes of structure for these heterogeneous polymers.In the present article,recent progresses in the studies on dynamic rheology for heterogeneous polymer systems including polymeric composites filled with inorganic particles,thermo-oxidized polyolefins,phase- separated polymeric blends and functional polymers with the scaling and percolation behavior are reviewed,mainly depending on the results by the authors' group.By means of rheological measurements,not only some new fingerprints responsible for the evolution of morphology and structure concerning these polymer systems are obtained,the corresponding results are also significant for the design and preparation of novel polymer-based composites and functional materials. 展开更多
关键词 Heterogeneous polymers Dynamic rheological properties PHASE-SEPARATION Morphology and structure scaling and percolation behavior
下载PDF
CLINICAL OBSERVATION ON POSTHERPETIC NEURALGIA OF HIV CARRIERS TREATED WITH ARRANGED ELECTRO ACUPUNCTURE
15
作者 李敏 《World Journal of Acupuncture-Moxibustion》 2000年第1期51-53,共3页
cases of postherpetic neuralgia were treated with arranged electro acupuncture and 30 cases with medicine as control. All cases were HIV carriers. The 6 point behavioral rating scale (BRS 6) was used to observe the ef... cases of postherpetic neuralgia were treated with arranged electro acupuncture and 30 cases with medicine as control. All cases were HIV carriers. The 6 point behavioral rating scale (BRS 6) was used to observe the effect before and after treatment. The results indicate arranged electro acupuncture can cure or reduce the severe pain of postherpetic neuralgia of HIV carriers and the effect was better than medicine. 展开更多
关键词 Arranged electro acupuncture Postherpetic neuralgia 6 point behavioral rating scales(BRS 6)
下载PDF
Modeling urban scale human mobility through big data analysis and machinelearning 被引量:1
16
作者 Yapan Liu Bing Dong 《Building Simulation》 SCIE EI CSCD 2024年第1期3-21,共19页
In the United States,the buildings sector consumes about 76%of electricity use and 40% of all primary energy use and associated greenhouse gas emissions.Occupant behavior has drawn increasing research interests due to... In the United States,the buildings sector consumes about 76%of electricity use and 40% of all primary energy use and associated greenhouse gas emissions.Occupant behavior has drawn increasing research interests due to its impacts on the building energy consumption.However,occupant behavior study at urban scale remains a challenge,and very limited studies have been conducted.As an effort to couple big data analysis with human mobility modeling,this study has explored urban scale human mobility utilizing three months Global Positioning System(GPS)data of 93,o00 users at Phoenix Metropolitan Area.This research extracted stay points from raw data,and identified users'home,work,and other locations by Density-Based Spatial Clustering algorithm.Then,daily mobility patterns were constructed using different types of locations.We propose a novel approach to predict urban scale daily human mobility patterns with 12-hour prediction horizon,using Long Short-Term Memory(LSTM)neural network model.Results shows the developed models achieved around 85%average accuracy and about 86%mean precision.The developed models can be further applied to analyze urban scale occupant behavior,building energy demand and flexibility,and contributed to urban planning. 展开更多
关键词 urban human mobility big data analysis urban scale occupant behavior recurrent neural networks
原文传递
Impact parameter dependence of the scaling of anisotropic flows in intermediate energy heavy-ion collisions
17
作者 颜廷志 李杉 《Chinese Physics C》 SCIE CAS CSCD 2014年第8期35-39,共5页
The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u 40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model. The nucleo... The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u 40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model. The nucleon- number scaling of elliptic flow exists and the scaling of the ratios of v4/v2 2 and v3/(v1v2) is applicable to collisions at almost all impact parameters except for peripheral collisions. 展开更多
关键词 impact parameter anisotropic flow scaling behavior
原文传递
Fracture behavior and self-sharpening mechanisms of polycrystalline cubic boron nitride in grinding based on cohesive element method 被引量:6
18
作者 Xin HUANG Haonan LI +1 位作者 Zhiwen RAO Wenfeng DING 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第12期2727-2742,共16页
Unlike monocrystalline cubic boron nitride(CBN), polycrystalline CBN(PCBN) shows not only higher fracture resistance induced by tool-workpiece interaction but also better selfsharpening capability;therefore, efforts h... Unlike monocrystalline cubic boron nitride(CBN), polycrystalline CBN(PCBN) shows not only higher fracture resistance induced by tool-workpiece interaction but also better selfsharpening capability;therefore, efforts have been devoted to the study of PCBN applications in manufacturing engineering. Most of the studies, however, remain qualitative due to difficulties in experimental observations and theoretical modeling and provide limited in-depth understanding of the self-sharpening behavior/mechanism. To fill this research gap, the present study investigates the self-sharpening process of PCBN abrasives in grinding and analyzes the macro-scale fracture behavior and highly localized micro-scale crack propagation in detail. The widely employed finite element(FE) method, together with the classic Voronoi diagram and cohesive element technique,is used considering the pronounced success of FE applications in polycrystalline material modeling.Grinding trials with careful observation of the PCBN abrasive morphologies are performed to validate the proposed method. The self-sharpening details, including fracture morphology, grinding force, strain energy, and damage dissipation energy, are studied. The effects of maximum grain cut depths(MGCDs) and grinding speeds on the PCBN fracture behavior are discussed, and their optimum ranges for preferable PCBN self-sharpening performance are suggested. 展开更多
关键词 Cohesive element theory Finite element model Fracture behavior scale PCBN abrasive grain Voronoi diagram
原文传递
Quantitative evaluation of severity of behavioral and psychological symptoms of dementia in patients with vascular dementia 被引量:2
19
作者 Wei-Dong Pan Sohei Yoshida +4 位作者 Qian Liu Chun-Lan Wu Jun Wang Jin Zhu Ding-Fang Cai 《Translational Neurodegeneration》 SCIE CAS 2013年第1期52-58,共7页
To quantitatively evaluate severity of behavioral and psychological symptoms of dementia(BPSD)for vascular dementia(VD).Changes of 51 patients with VD in BPSD between the first and 24th week were assessed using the Ne... To quantitatively evaluate severity of behavioral and psychological symptoms of dementia(BPSD)for vascular dementia(VD).Changes of 51 patients with VD in BPSD between the first and 24th week were assessed using the Neuropsychiatric Inventory(NPI)and the behavioral pathology in Alzheimer’s disease(BEHAVE-AD)rating scale,in detrended fluctuation analysis(DFA)represented by diurnal activity(DA),evening activity(EA),and nocturnal activity(NA),and the relationships were analyzed.The subscores of activity disturbances,diurnal rhythm disturbances,and anxieties and phobias in the BEHAVE-AD score,and that of agitation,irritability,and sleep disorder in the NPI score were significantly increased compared with the first week,as was for the changes for EA in the DFA value.A linear correlation was observed between the changes of activity disturbances plus anxieties and phobias,and those of DA,and between the development of diurnal rhythm and those of EA,the vehement and autism scores and those of DA,and the difference in sleep disorder scores and those of EA,respectively.Analysis of DA,NA,and EA may reflect the fluctuational degrees of VD-BPSD,can provide a useful assessment of VD-BPSD accompanied by clinical scores for VD. 展开更多
关键词 Vascular dementia behavioral and psychological symptoms of dementia Rating scale of the behavioral pathology in Alzheimer’s disease Neuropsychiatric inventory ACTIGRAPH
原文传递
Parity Symmetry and Parity Breaking in the Quantum Rabi Model with Addition of Ising Interaction
20
作者 王琼 贺志 姚春梅 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第4期510-514,共5页
We explore the possibility to generate new parity symmetry in the quantum Rabi model after a bias is introduced. In contrast to a mathematical treatment in a previous publication [J. Phys. A 46(2013) 265302], we consi... We explore the possibility to generate new parity symmetry in the quantum Rabi model after a bias is introduced. In contrast to a mathematical treatment in a previous publication [J. Phys. A 46(2013) 265302], we consider a physically realistic method by involving an additional spin into the quantum Rabi model to couple with the original spin by an Ising interaction, and then the parity symmetry is broken as well as the scaling behavior of the ground state by introducing a bias. The rule can be found that the parity symmetry is broken by introducing a bias and then restored by adding new degrees of freedom. Experimental feasibility of realizing the models under discussion is investigated. 展开更多
关键词 parity symmetry parity breaking Rabi model scaling behavior
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部