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Dispersion Relations in Diffraction in Time
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作者 Salvador Godoy Karen Villa 《Applied Mathematics》 2024年第7期464-468,共5页
In agreement with Titchmarsh’s theorem, we prove that dispersion relations are just the Fourier-transform of the identity, g(x′)=±Sgn(x′)g(x′), which defines the property of being a truncated functions at the... In agreement with Titchmarsh’s theorem, we prove that dispersion relations are just the Fourier-transform of the identity, g(x′)=±Sgn(x′)g(x′), which defines the property of being a truncated functions at the origin. On the other hand, we prove that the wave-function of a generalized diffraction in time problem is just the Fourier-transform of a truncated function. Consequently, the existence of dispersion relations for the diffraction in time wave-function follows. We derive these explicit dispersion relations. 展开更多
关键词 Diffraction in time Dispersion relations Hilbert Transforms
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Advancements in Time Modeling: Relationalism, Divisional Structures, and Geometry
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作者 Steven D. P. Moore 《Journal of Applied Mathematics and Physics》 2024年第10期3358-3383,共26页
This article broadens terminology and approaches that continue to advance time modelling within a relationalist framework. Time is modeled as a single dimension, flowing continuously through independent privileged poi... This article broadens terminology and approaches that continue to advance time modelling within a relationalist framework. Time is modeled as a single dimension, flowing continuously through independent privileged points. Introduced as absolute point-time, abstract continuous time is a backdrop for concrete relational-based time that is finite and discrete, bound to the limits of a real-world system. We discuss how discrete signals at a point are used to temporally anchor zero-temporal points [t = 0] in linear time. Object-oriented temporal line elements, flanked by temporal point elements, have a proportional geometric identity quantifiable by a standard unit system and can be mapped on a natural number line. Durations, line elements, are divisible into ordered unit ratio elements using ancient timekeeping formulas. The divisional structure provides temporal classes for rotational (Rt24t) and orbital (Rt18) sample periods, as well as a more general temporal class (Rt12) applicable to either sample or frame periods. We introduce notation for additive cyclic counts of sample periods, including divisional units, for calendar-like formatting. For system modeling, unit structures with dihedral symmetry, group order, and numerical order are shown to be applicable to Euclidean modelling. We introduce new functions for bijective and non-bijective mapping, modular arithmetic for cyclic-based time counts, and a novel formula relating to a subgroup of Pythagorean triples, preserving dihedral n-polygon symmetries. This article presents a new approach to model time in a relationalistic framework. 展开更多
关键词 relatIONALISM Mohist Geometry Euclidean Geometry relational-time Discrete-time CONTINUOUS-time Planck time Zero-time
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Biliary tract injury caused by different relative warm ischemia time in liver transplantation in rats 被引量:24
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作者 Zhao, Hong-Feng Zhang, Guo-Wei +3 位作者 Zhou, Jie Lin, Jian-Hua Cui, Zhong-Lin Li, Xiang-Hong 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2009年第3期247-254,共8页
BACKGROUND: There is a controversy over the degree of liver and biliary injury caused by the period of secondary warm ischemia. A liver autotransplantation model was adopted because it excludes the effects of infectio... BACKGROUND: There is a controversy over the degree of liver and biliary injury caused by the period of secondary warm ischemia. A liver autotransplantation model was adopted because it excludes the effects of infection and immunological rejection on bile duct injury. This study was undertaken to assess biliary tract injury caused by relative warm ischemia (secondary warm ischemia time in the biliary tract) and reperfusion. METHODS: One hundred and two rats were randomly divided into 5 groups: group I (control); groups 11 to V, relative warm ischemia times of 0 minute, 30 minutes, I hour and 2 hours. In addition to the levels of serum alkaline phosphatase, and total bilirubin, pathomorphology assessment and TUNEL assay were performed to evaluate biliary tract damage. RESULTS: Under the conditions that there were no significant differences in warm ischemia time, cold perfusion time and anhepatic phase, group comparisons showed statistically significant differences. The least injury occurred in group H (portal vein and hepatic artery reperfused simultaneously) but the most severe injury occurred in group V (biliary tract relative warm ischemia time 2 hours). CONCLUSIONS: Relative warm ischemia is one of the factors that result in bile duct injury, and the relationship between relative warm ischemia time the bile injury degree is time-dependent. Simultaneous arterial and portal reperfusion is the best choice to avoid the bile duct injury caused by relative warm ischemia. (Hepatobiliary Pancreat Dis Int 2009; 8: 247-254) 展开更多
关键词 liver transplantation bile duct ischemia-reperfusion injury relative warm ischemia time models animal RAT
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A QSRR Study on the Relative Retention Time of Halogenated Methyl-phenyl Ethers 被引量:5
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作者 XU Hui-Ying YU Qing-Sen +3 位作者 ZOU Jian-Wei WANG Yan-Hua WANG Hong-Qing CHEN Xue-Song 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第7期811-817,共7页
Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 hal... Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 halogenated anisoles at the HF/6-31 G^* level. A number of statistically based parameters have been obtained. By multiple regression method, linear relationships between the gas-chromatographic relative retention time (RRT) and structural descriptors have been established for the training set of 32 halogenated anisoles. The result showed that the parameters derived from electrostatic potentials (ESPs) together with the molecular volume (Vmc) could be well used to express the quantitative structure-RRT relationships of halogenated anisoles. The best two-variable regression model gives a correlation coefficient of 0.980 and a standard deviation of 0.07, and the leave-one-out cross-validated correlation coefficient is 0.975. The goodness of the model has been further validated through exploring the predictive power for the testing set of 10 halogenated anisoles. 展开更多
关键词 halogenated methyl-phenyl ethers (anisoles) molecular electrostatic potentials (ESPs) relative retention time (RRT) QSRR
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Hopf bifurcation control for a coupled nonlinear relative rotation system with time-delay feedbacks 被引量:1
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作者 刘爽 李雪 +1 位作者 谈书贤 李海滨 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期299-305,共7页
This paper investigates the Hopf bifurcations resulting from time delay in a coupled relative-rotation system with time- delay feedbacks. Firstly, considering external excitation, the dynamical equation of relative ro... This paper investigates the Hopf bifurcations resulting from time delay in a coupled relative-rotation system with time- delay feedbacks. Firstly, considering external excitation, the dynamical equation of relative rotation nonlinear dynamical system with primary resonance and 1:1 internal resonance under time-delay feedbacks is deduced. Secondly, the averaging equation is obtained by the multiple scales method. The periodic solution in a closed form is presented by a perturbation approach. At last, numerical simulations confirm that time-delay theoretical analyses have influence on the Hopf bifurcation point and the stability of periodic solution. 展开更多
关键词 relative rotation coupled nonlinear system BIFURCATION time delay
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Predicting the Relative Retention Time (RRT) of Polybrominated Diphenyl Ethers (PBDEs) 被引量:2
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作者 Shu Shen LIU Yan LIU +1 位作者 Da Qiang YIN Lian Sheng WANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第11期1559-1562,共4页
Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time (RRT) of polybrominated diphenyl ethers (PBDEs) were predic... Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time (RRT) of polybrominated diphenyl ethers (PBDEs) were predicted. A four-variable regression model (M30) with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom -C= and -C=, -C= and 〉C=, 〉C= and 〉C=, -C= and -Br. 展开更多
关键词 Polybrominated diphenyl ethers (PBDEs) relative retention time (RRT) molecular electronegativity distance vector (MEDV).
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The determination of the relative permittivity of periodic stratified media based on the iterative time-reversal method 被引量:1
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作者 章志敏 王秉中 +2 位作者 梁木生 纪晴 宋钢兵 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第4期694-699,共6页
In this paper, we present a new method to determine the relative permittivity of periodic stratified media using the iterative time-reversal method. Based on transmission line theory, the focal peak value of iterative... In this paper, we present a new method to determine the relative permittivity of periodic stratified media using the iterative time-reversal method. Based on transmission line theory, the focal peak value of iterative time-reversal electro- magnetic waves, which contain information about the periodic stratified medium, is computed in pulse-echo mode. Using the relationship between the focal peak value and the relative permittivity of the periodic stratified medium, the relative permittivity can be obtained by measuring the focal peak value. Numerical simulations are conducted, and the results demonstrate the feasibility of the proposed approach to the measurement of the relative permittivity of a periodic stratified medium. 展开更多
关键词 iterative time reversal periodic stratified medium peak value detection relative permittivity determination
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Quantitative structure retention relationship studies for predicting relative retention times of chlorinated phenols on gas chromatography
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作者 LiSY SunC 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2002年第3期418-422,共5页
A new method of quantitative structure retention relationship(QSRR) studies was reported for predicting gas chromatography(GC) relative retention times(RRTs) of chlorinated phenols (CPs) using a DB 5 column. Chemica... A new method of quantitative structure retention relationship(QSRR) studies was reported for predicting gas chromatography(GC) relative retention times(RRTs) of chlorinated phenols (CPs) using a DB 5 column. Chemical descriptors were calculated from the molecular structure of CPs and related to their gas chromatographic RRTs by using multiple linear regression analysis. The proposed model had a multiple square correlation coefficient R 2=0.970, standard error SE =0.0472, and significant level P =0.0000. The QSRR model also reveals that the gas chromatographic relative retention times of CPs are associated with physicochemical property interactions with the stationary phase,and influenced by the number of chlorine and oxygen in the CP melecules. 展开更多
关键词 QSRR relative retention times molecular descriptors chlorinated phenols
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Relative Time Quantum-based Enhancements in Round Robin Scheduling
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作者 Sardar Zafar Iqbal Hina Gull +5 位作者 Saqib Saeed Madeeha Saqib Mohammed Alqahtani Yasser A.Bamarouf Gomathi Krishna May Issa Aldossary 《Computer Systems Science & Engineering》 SCIE EI 2022年第5期461-477,共17页
Modern human life is heavily dependent on computing systems and one of the core components affecting the performance of these systems is underlying operating system.Operating systems need to be upgraded to match the n... Modern human life is heavily dependent on computing systems and one of the core components affecting the performance of these systems is underlying operating system.Operating systems need to be upgraded to match the needs of modern-day systems relying on Internet of Things,Fog computing and Mobile based applications.The scheduling algorithm of the operating system dictates that how the resources will be allocated to the processes and the Round Robin algorithm(RR)has been widely used for it.The intent of this study is to ameliorate RR scheduling algorithm to optimize task scheduling.We have carried out an experimental study where we have developed four variations of RR,each algorithm considers three-time quanta and the performance of these variations was compared with the RR algorithm,and results highlighted that these variations performed better than conventional RR algorithm.In the future,we intend to develop an automated scheduler that can determine optimal algorithm based on the current set of processes and will allocate time quantum to the processes intelligently at the run time.This way the task performance of modern-day systems can be improved to make them more efficient. 展开更多
关键词 CPU scheduling Round Robin enhanced Round Robin relative time quantum operating systems
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Time Related Influence of α-Mercapto-β-(2-Furyl) Acrylic Acid (MFA) in Cadmium Toxicity 被引量:1
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作者 SHASHI KHANDELWAL SUSHIL K.TANDON 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1991年第3期304-309,共6页
The effect of a-mercapto-β-(2-furyl) acrylic acid (MFA, 200 mg/kg, oral) administered 30 min or 24 h post cadmium (1 mg/kg, i.p.) exposure on cadmium toxicity, was investigated in rats. The Cd induced hepatic metallo... The effect of a-mercapto-β-(2-furyl) acrylic acid (MFA, 200 mg/kg, oral) administered 30 min or 24 h post cadmium (1 mg/kg, i.p.) exposure on cadmium toxicity, was investigated in rats. The Cd induced hepatic metallothionein was reduced by MFA treatment parallel to the depletion of hepatic Cd. However, in renal tissue,MFA caused only redistribution of metal from the paniculate to the soluble fraction. Hepatic and renal Zn and renal Cu were significantly increased on Cd exposure. MFA therapy, however, lowered the hepatic Zn and increased the renal Cu levels. The action of MFA appears to be via metal chelation rather than by MT induction. 展开更多
关键词 MFA Acrylic Acid in Cadmium Toxicity Mercapto FURYL time related Influence of
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Time series analysis of correlativity between pulmonary tuberculosis and seasonal meteorological factors based on theory of Human-Environmental Inter Relation 被引量:2
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作者 Keerqinfu Qiming Zhang +1 位作者 Long Yan Juan He 《Journal of Traditional Chinese Medical Sciences》 2018年第2期119-127,共9页
Objective:This paper aims to study the correlativity between the number of pulmonary tuberculosis (PTB) cases and seasonal meteorological factors in Beijing.Methods:Based on theory of Human-Environmental Inter Relatio... Objective:This paper aims to study the correlativity between the number of pulmonary tuberculosis (PTB) cases and seasonal meteorological factors in Beijing.Methods:Based on theory of Human-Environmental Inter Relation in Huangdi's Internal Classics,we adopted monthly cases of PTB in Beijing from 2004 to 2011,and established a Seasonal Autoregressive Integrated Moving Average (SARIMA) model.Using the cross-correlation function (CCF),we then analyzed the correlation between meteorological factors and number of infected patients.The related meteorological factors were subsequently integrated,to establish a Seasonal Autoregressive Integrated Moving Average with explanatory variables (SARIMAX) model,which was used to estimate and verify the number of PTB cases in 2012.Results:In this study,a SARIMA(0,1,1) (0,1,1)12 model was established;CCF analysis was used to reveal the correlativity between PTB and precipitation with 1 lag,relative humidity with 1 lag.Then,integrated with relative humidity with 1 lag (β =2.405,95% confidence interval:0.433-4.377),the SARIMAX prediction model was proved to be an accurate approach for predicting local situations of PTB occurrence.Conclusions:The occurrence of PTB is correlated with seasonal meteorological factors.Combining these factors,an exact prediction model can be established,to estimate of the number of PTB infected patients. 展开更多
关键词 HUMAN -Environmental INTER relatION Pulmonary tuberculosis time series analysis SEASONAL Autoregressive Integrated Moving Average
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Extension of Subjective Logic for Time-Related Trust 被引量:3
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作者 HUANGChen-lin HUHua-ping 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第1期56-60,共5页
To describe the dynamic propcrty of trust relationship, wt propose atime-related trust model and extend Joang's subjective logic to fit for time-related trust model.The extension includes prepositional conjunction... To describe the dynamic propcrty of trust relationship, wt propose atime-related trust model and extend Joang's subjective logic to fit for time-related trust model.The extension includes prepositional conjunction, disjunction and negation for traditional logic anddiscounting and consensus operators that are evidential operators specially designed for thepropagation and computation of trust relationships. With the extension of subjective logic fortime-related trust, our time-related trust modelis suitable to model the dynamic trust relationshipin practice. Finally an example of reputation assessment is offered to demonstrate the usage of ourtrust model. 展开更多
关键词 trust model lime-related trust relationship time-related trust model subjective logic
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Grey interpolation approach for small time-lag samples based on grey dynamic relation analysis
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作者 WANG Junjie DANG Yaoguo +1 位作者 XU Ning DING Song 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第1期105-115,共11页
Given a non-equidistant sequence or an equidistant series with one or more outliers, a grey interpolation approach considering the time lags is established for producing the missing data or correcting the abnormal val... Given a non-equidistant sequence or an equidistant series with one or more outliers, a grey interpolation approach considering the time lags is established for producing the missing data or correcting the abnormal values. To accomplish this, a new grey incidence model, called the grey dynamic incidence model GDIM(t), is constructed for determining whether the factors are effective to the known factor and what the time lag is between a useful factor and the specified sequence. Based on the results of the GDIM(t) model, two programming problems are designed to obtain the upper and lower bounds of the unknown or abnormal values which are regarded as grey numbers. The solutions based on the particle swarm optimization(PSO) for the nonlinear programming problems are given. To explain how it can be used in practice, this new grey interpolation approach is applied to correct an abnormal value in the sequence of an agriculture environment problem. 展开更多
关键词 grey interpolation grey relational analysis time lags programming problems
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Comparison of time-related electrical properties of PN junctions and Schottky diodes for Zn O-based betavoltaic batteries 被引量:2
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作者 Xiao-Yi Li Jing-Bin Lu +4 位作者 Ren-Zhou Zheng Yu Wang Xu Xu Yu-Min Liu Rui He 《Nuclear Science and Techniques》 SCIE CAS CSCD 2020年第2期55-66,共12页
Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries,in which 0.101121 Ci 63Ni was selected as the beta source.The time-related electrical properties were o... Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries,in which 0.101121 Ci 63Ni was selected as the beta source.The time-related electrical properties were obtained using Monte Carlo simulations.For the n-type ZnO,the Pt/ZnO Schottky diode had the highest energy conversion efficiency,and the Ni/ZnO Schottky diode had the largest Isc.The overall electrical performance of PN junctions is better than that of Schottky diodes.The lifetimes of Pt/ZnO and Ni/ZnO are longer than for other Schottky devices,coming close to those of PN junctions.Considering that Schottky diodes are easier to fabricate and independent of p-type semiconductors,Pt/ZnO and Ni/ZnO diodes offer alternatives to PN-junction-based betavoltaic batteries. 展开更多
关键词 Beta voltaic effect Zinc oxide time-related properties PN junction Schottky diode Monte Carlo simulation
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Cross-Correlation of Station-to-Station Free Surface Elevation Time Series for Breaking Water Waves
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作者 Raphael Mukaro 《Applied Mathematics》 2018年第2期138-152,共15页
Free surface elevation time series of breaking water waves were measured in a laboratory flume. This was done in order to analyze changes in wave characteristics as the waves propagated from deep water to the shore. A... Free surface elevation time series of breaking water waves were measured in a laboratory flume. This was done in order to analyze changes in wave characteristics as the waves propagated from deep water to the shore. A pair of parallel- wire capacitive wave gages was used to simultaneously measure free surface elevations at different positions along the flume. One gage was kept fixed near the wave generator to provide a reference while the other was moved in steps of 0.1 m in the vicinity of the break point. Data from these two wave gages measured at the same time constitute station-to-station free surface elevation time series. Fast Fourier Transform (FFT) based cross-correlation techniques were employed to determine the time lag between each pair of the time series. The time lag was used to compute the phase shift between the reference wave gage and that at various points along the flume. Phase differences between two points spaced 0.1 m apart were used to calculate local mean wave phase velocity for a point that lies in the middle. Results show that moving from deep water to shallow water, the measured mean phase velocity decreases almost linearly from about 1.75 m/s to about 1.50 m/s at the break point. Just after the break point, wave phase velocity abruptly increases to a maximum value of 1.87 m/s observed at a position 30 cm downstream of the break point. Thereafter, the phase velocity decreases, reaching a minimum of about 1.30 m/s. 展开更多
关键词 Turbulence Plunging BREAKER time Series CROSS-CORrelatION relative PHASE PHASE Velocity
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Gravitational Space-Time Quantization for Charged Wormholes and the Diophantine Uncertainty Relation 被引量:1
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作者 Yu. A. Khlestkov A. Yu. Khlestkov +2 位作者 P. Yu. Lukashin M. Yu. Lukashin N. Yu. Lukashina 《Journal of Modern Physics》 2020年第11期1761-1778,共18页
This research work proceeds from the assumption, which was still considered by Einstein, that the quantization of gravity does not require additional external procedures: quantum phenomena can be a consequence of the ... This research work proceeds from the assumption, which was still considered by Einstein, that the quantization of gravity does not require additional external procedures: quantum phenomena can be a consequence of the properties of the universal gravitational interaction, which maps any physical field upon the space-time geometry. Therefore, an attempt is made in this research work to reduce the quantization of physical fields in GRT to the space-time quantization. Three reasons for quantum phenomena are considered: Partition of space-time into a set of unconnected Novikov’s R- and T-domains impenetrable for light paths;the set is generated by the invariance of Einstein’s equations with respect to dual mappings;The existence of electric charge quanta of wormholes, which geometrically describe elementary particles in GRT. This gives rise to a discrete spectrum of their physical and geometric parameters governed by Diophantine equations. It is shown that the fundamental constants (electric charge, rest masses of an electron and a proton) are interconnected arithmetically;The existence of the so-called Diophantine catastrophe, when fluctuations in the values of physical constants tending to zero lead to fluctuations in the number of electric charges and the number of nucleons at the wormhole throats, which tend to infinity, so that the product of the increments of these numbers by the increment of physical constants forms a relation equivalent to the uncertainty relation in quantum mechanics. This suggests that space-time cannot but fluctuate, and, moreover, its fluctuations are bounded from below, so that all processes become chaotic, and the observables become averaged over this chaos. 展开更多
关键词 Quantization of Gravitation Novikov’s R- and T-Domains Diophantine Uncertainty relations Discretization of Space-time
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A Study of Visual Event-Related Potential and Reaction Time in Elderly People: Comparative Analysis of the Scores of Intelligence Test in 30 Subjects
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作者 杨文俊 潘速跃 《Journal of Medical Colleges of PLA(China)》 CAS 1990年第3期222-226,共5页
The results of visual event-related potential(ERP)examinations and reactiontime(RT)tests were reported in 30 elders and compared with their performanceintellegence quotient(PIQ)scores.The subjects consisted of 18 male... The results of visual event-related potential(ERP)examinations and reactiontime(RT)tests were reported in 30 elders and compared with their performanceintellegence quotient(PIQ)scores.The subjects consisted of 18 males and 12 femalesaged 50-71(mean 61.4)years old.No history of central nervous system disease wasfound.The visual stimuli were randomly presented to the subject,including three sym-bols:E as target stimulus with 0.15 probability,and H and E as nontarget stimuliwith 0.15 and 0.70 probability respectively.The recording electrodes were placed on Fzand Pz.The duration from the subject seeing the target to touching a button immediatelywas considered as reaction time(RT).It was shown that the P3 latency at Pz was longer than that at Fz and the P3amplitude at Pz was larger than that at Fz,and that the RT was longer than P3 latencywith obvious effect of distribution(P【0.05 at Fz and P】0.05 at Pz)as well .The higherthe PIQ scores,the longer the RT and the P3 latency.It is suggested that the ERPmight reflect the differences of PIQ scores,and the P3 is an objective index.We considerthat the research of ERP is of great interest in the neuropsychological and neurological sci-ences. 展开更多
关键词 ELDER EVENT-relatED potential REACTION time INTELLIGENCE test
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The Executive Function of Temporal Distribution in Time Personality: An ERP (Event-Related Potential) Study
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作者 Guoguang Cao Yong Zheng 《Psychology Research》 2013年第9期495-503,共9页
关键词 事件相关电位 时空分布特征 时间分布 ERP 人格 一致性条件 时间模式 调查活动
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Computational uncertainty and optimal grid size and time step of the Lax-Friedrichs scheme for the 1D advection equation
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作者 Jing Cao Jianping Li Yanjie Li 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第3期46-51,共6页
本文对于应用Lax-Friedrichs格式数值求解一维平流方程,研究数值求解过程中产生的截断误差与舍入误差,以及两种误差逐层向高时间层传播的累积,得到新的数值解总误差上界的理论近似公式,以及最优格距和最优时间步长的理论公式.通过数值... 本文对于应用Lax-Friedrichs格式数值求解一维平流方程,研究数值求解过程中产生的截断误差与舍入误差,以及两种误差逐层向高时间层传播的累积,得到新的数值解总误差上界的理论近似公式,以及最优格距和最优时间步长的理论公式.通过数值算例验证了所得公式的可靠性。然后,发现了两种不同机器精度下最优时间步长之比满足的一个仅与机器精度有关的普适关系.最后,理论验证了在网格比固定的情况下,此问题满足数值计算的不确定性原理,以及在机器有限精度下最优时间步长的必然存在。 展开更多
关键词 Lax-Friedrichs格式 数值计算的不确定性原理 最优格距 最优时间步长 普适关系
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具有系数相关性的可变分数时延滤波器设计方法 被引量:1
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作者 庄陵 刘莹 宋诗苇 《通信学报》 EI CSCD 北大核心 2024年第4期137-145,共9页
针对可变分数时延滤波器设计中的复杂度问题提出一种设计方法,将时域插值与泰勒级数展开相结合对Farrow结构进行系数配置,推导出相应的滤波器系数相关公式。该方法设计出的滤波器具有系数相关性,可使近一半滤波器系数独立,并得到低复杂... 针对可变分数时延滤波器设计中的复杂度问题提出一种设计方法,将时域插值与泰勒级数展开相结合对Farrow结构进行系数配置,推导出相应的滤波器系数相关公式。该方法设计出的滤波器具有系数相关性,可使近一半滤波器系数独立,并得到低复杂度的滤波器实现结构。从复杂度、幅频响应及群时延、误差方面进行理论推导和仿真验证,分析结果表明,所提方法能有效降低可变分数时延滤波器的复杂度和计算成本。 展开更多
关键词 可变分数时延滤波器 时域插值 系数相关性 复杂度
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