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Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1134-1162,共29页
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an... The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles. 展开更多
关键词 ELECTRON POSITRON Wave Function Solution Electromagnetic Spin Mass Charge Proof Fundamental Particle Properties Quantum Mechanics Classical Physics Computer 3D Model Schrödinger Equation RMS KLEIN GORDON Electric Magnetic Lorentz Invariant Hertzian Vector Point Potential Field Density Phase Flow Attraction REPULSION Shell theorem Ehrenfest VIRIAL normalization Harmonic Oscillator
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Normalized edge detection, and the horizontal extent and depth of geophysical anomalies 被引量:2
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作者 李丽丽 韩立国 黄大年 《Applied Geophysics》 SCIE CSCD 2014年第2期149-157,252,253,共11页
Edge detection is an image processing technique for finding the boundaries of objects within images. It is typically used to interpret gravity and magnetic data, and find the horizontal boundaries of geological bodies... Edge detection is an image processing technique for finding the boundaries of objects within images. It is typically used to interpret gravity and magnetic data, and find the horizontal boundaries of geological bodies. Large deviations between model and true edges are common because of the interference of depth and errors in computing the derivatives; thus, edge detection methods cannot provide information about the depth of the source. To simultaneously obtain the horizontal extent and depth of geophysical anomalies, we use normalized edge detection filters, which normalize the edge detection function at different depths, and the maxima that correspond to the location of the source. The errors between model and actual edges are minimized as the depth of the source decreases and the normalized edge detection method recognizes the extent of the source based on the maxima, allowing for reliable model results. We demonstrate the applicability of the normalized edge detection filters in defining the horizontal extent and depth using synthetic and actual aeromagnetic data. 展开更多
关键词 geophysical anomalies normalized edge detection normalized total horizontal derivative regularization tilt angle theta map
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Supervised Feature Learning for Offline Writer Identification Using VLAD and Double Power Normalization
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作者 Dawei Liang Meng Wu Yan Hu 《Computers, Materials & Continua》 SCIE EI 2023年第7期279-293,共15页
As an indispensable part of identity authentication,offline writer identification plays a notable role in biology,forensics,and historical document analysis.However,identifying handwriting efficiently,stably,and quick... As an indispensable part of identity authentication,offline writer identification plays a notable role in biology,forensics,and historical document analysis.However,identifying handwriting efficiently,stably,and quickly is still challenging due to the method of extracting and processing handwriting features.In this paper,we propose an efficient system to identify writers through handwritten images,which integrates local and global features from similar handwritten images.The local features are modeled by effective aggregate processing,and global features are extracted through transfer learning.Specifically,the proposed system employs a pre-trained Residual Network to mine the relationship between large image sets and specific handwritten images,while the vector of locally aggregated descriptors with double power normalization is employed in aggregating local and global features.Moreover,handwritten image segmentation,preprocessing,enhancement,optimization of neural network architecture,and normalization for local and global features are exploited,significantly improving system performance.The proposed system is evaluated on Computer Vision Lab(CVL)datasets and the International Conference on Document Analysis and Recognition(ICDAR)2013 datasets.The results show that it represents good generalizability and achieves state-of-the-art performance.Furthermore,the system performs better when training complete handwriting patches with the normalization method.The experimental result indicates that it’s significant to segment handwriting reasonably while dealing with handwriting overlap,which reduces visual burstiness. 展开更多
关键词 Writer identification power normalization vector of locally aggregated descriptors feature extraction
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Comparisons of ganglion cell-inner plexiform layer loss patterns and its diagnostic performance between normal tension glaucoma and primary open angle glaucoma: a detailed, severity-based study 被引量:2
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作者 Xiao-Yu Xu Kun-Bei Lai +3 位作者 Hui Xiao Yi-Quan Lin Xin-Xing Guo Xing Liu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第1期71-78,共8页
AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess ... AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess the diagnostic capabilities of GCIPL thickness parameters in discriminating NTG or POAG from normal subjects.METHODS: A total of 157 eyes of 157 subjects, including 57 normal eyes, 51 eyes with POAG and 49 eyes with NTG were enrolled and strictly matched in age, refraction, and disease severity between POAG and NTG groups. The average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness, and the average, superior, temporal, inferior, and nasal retinal nerve fiber layer(RNFL) thickness were obtained by Cirrus optical coherence tomography(OCT). The diagnostic capabilities of OCT parameters were assessed by area under receiver operating characteristic(AUROC) curves. RESULTS: Among all the OCT thickness parameters, no statistical significant difference between NTG group and POAG group was found(all P>0.05). In discriminating NTG or POAG from normal subjects, the average and inferior RNFL thickness, and the minimum GCIPL thickness had better diagnostic capabilities. There was no significant difference in AUROC curve between the best GCIPL thickness parameter(minimum GCIPL) and the best RNFL thickness parameter in discriminating NTG(inferior RNFL;P=0.076) and indiscriminating POAG(average RNFL;P=0.913) from normal eyes.CONCLUSION: Localized GCIPL loss, especially in the inferior and inferotemporal sectors, is more common in NTG than in POAG. Among all the GCIPL thickness parameters, the minimum GCIPL thickness has the best diagnostic performance in differentiating NTG or POAG from normal subjects, which is comparable to that of the average and inferior RNFL thickness. 展开更多
关键词 normal tension glaucoma primary open angle glaucoma spectral domain optical coherence tomography ganglion cell-inner plexiform layer thickness PATTERN
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Intraocular retinal thickness asymmetry in early stage of primary open angle glaucoma and normal tension glaucoma 被引量:1
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作者 Pei-Wen Lin Hsueh-Wen Chang +2 位作者 Ing-Chou Lai Jen-Chia Tsai Yi-Chieh Poon 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2018年第8期1342-1351,共10页
AIM: To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer(pR NFL) and macular layers measured by spectral-domain optical coherence tomography(SD-OCT) in patients w... AIM: To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer(pR NFL) and macular layers measured by spectral-domain optical coherence tomography(SD-OCT) in patients with early stage of primary open angle glaucoma(POAG) and normal tension glaucoma(NTG).METHODS: A total of 117 patients with early stage of glaucoma(54 patients with POAG and 63 patients with NTG) and 32 normal subjects were recruited for the study. The pR NFL thickness, total macular layer(TML) thickness, and isolated inner macular layer(IML) thickness were measured by SD-OCT. Hemisphere TML thickness asymmetry measured by the posterior pole asymmetry scan was evaluated. Thickness differences of pR NFL and IML between superior and inferior quadrants were calculated. Asymmetry indices(AIs) of the p RNFL, TML and isolated IML were also computed. Areas under the receiver-operating characteristic curves(AROCs) were generated to determine the diagnostic capabilities of different parameters. RESULTS: Intraocular p RNFL thickness differences and AIs between the superior and inferior quadrants were significantly different between normal and NTG groups(P=0.009 and P〈0.001, respectively). Intraocular p RNFL thickness differences and AIs between the temporal-superior and temporal-inferior sectors were also significantly different between normal and NTG groups(P=0.035 and P〈0.001, respectively). The thickness differences and AIs of TML between superior and inferior hemispheres were significantly different between normal and NTG groups(P=0.001 and P=0.001, respectively) and between normal and POAG groups(P=0.032 and P=0.020, respectively). The thickness differences and AIs of macular ganglion cell layer(mG CL) between superior and inferior quadrants were significantly different between normal and NTG groups(P=0.013 and P=0.004, respectively), and between NTG and POAG groups(P=0.015 and P=0.012, respectively). The thickness difference of TML between superior and inferior hemispheres showed the highest diagnostic capability for early NTG eyes(AROC=0.832).CONCLUSION: Intraocular retinal thickness asymmetry in pR NFL, TML and mG CL are found in early stage of NTG. Hemisphere TML thickness asymmetry is also found in POAG eyes. Asymmetry analysis of retinal thickness can be an adjunctive modality for early detection of glaucoma. 展开更多
关键词 retinal nerve fiber layer macular thickness primary open angle glaucoma normal tension glaucoma hemisphere retinal asymmetry optical coherence tomography
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Prediction of Ground Vibration Induced by Rock Blasting Based on Optimized Support Vector Regression Models
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作者 Yifan Huang Zikang Zhou +1 位作者 Mingyu Li Xuedong Luo 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期3147-3165,共19页
Accurately estimating blasting vibration during rock blasting is the foundation of blasting vibration management.In this study,Tuna Swarm Optimization(TSO),Whale Optimization Algorithm(WOA),and Cuckoo Search(CS)were u... Accurately estimating blasting vibration during rock blasting is the foundation of blasting vibration management.In this study,Tuna Swarm Optimization(TSO),Whale Optimization Algorithm(WOA),and Cuckoo Search(CS)were used to optimize two hyperparameters in support vector regression(SVR).Based on these methods,three hybrid models to predict peak particle velocity(PPV)for bench blasting were developed.Eighty-eight samples were collected to establish the PPV database,eight initial blasting parameters were chosen as input parameters for the predictionmodel,and the PPV was the output parameter.As predictive performance evaluation indicators,the coefficient of determination(R2),rootmean square error(RMSE),mean absolute error(MAE),and a10-index were selected.The normalizedmutual information value is then used to evaluate the impact of various input parameters on the PPV prediction outcomes.According to the research findings,TSO,WOA,and CS can all enhance the predictive performance of the SVR model.The TSO-SVR model provides the most accurate predictions.The performances of the optimized hybrid SVR models are superior to the unoptimized traditional prediction model.The maximum charge per delay impacts the PPV prediction value the most. 展开更多
关键词 Blasting vibration metaheuristic algorithms support vector regression peak particle velocity normalized mutual information
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The change of anterior segment parameters after cataract surgery in normal-tension glaucoma 被引量:3
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作者 Wonseok Lee Hyoung Won Bae +1 位作者 Chart Yun Kim Gong Je Seong 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2017年第8期1239-1245,共7页
AIM: To investigate the change of anterior chamber angle morphology and intraocular pressure (lOP) reduction after cataract surgery in patients with normal-tension glaucoma (NTG) using swept-source optical cohere... AIM: To investigate the change of anterior chamber angle morphology and intraocular pressure (lOP) reduction after cataract surgery in patients with normal-tension glaucoma (NTG) using swept-source optical coherence tomography (SS-OCT). METHODS: This prospective, comparative, observational study recruited patients into two groups. Group 1 was the control group including normal subjects except those with cataracts (cataract group, n=67 eyes of 67 patients), and group 2 was NTG group including patients who were diagnosed with NTG and cataracts (n=43 eyes of 43 patients), which were treated with phacoemulsification and intraocular lens implantation. Before surgery, and at postoperative 1 and 6too, anterior chamber angles were evaluated by SS-OCT under dark conditions using three- dimensional angle analysis scan protocol. Angle opening distance (AOD), angle recess area (ARA), and trabecular- iris surface area (TISA) at four quadrants (temporal, nasal, superior, and inferior) were calculated automatically by SS-OGT, after the observer marked scleral spurs. RESULTS: A total of 106 patients (54 males and 52 females) were enrolled in the study. Angle parameters, AOD, ARA, and TISA were increased after surgery in both groups. However, changes of angle parameters were only significant in group 2. In group 2, preoperative lOP was 13.2+2.9 mm Hg, and postoperative lOP at 1 and 6mo were 10.5+3.0 and 10.7+2.8 mm Hg, respectively. In group 1, preoperative lOP was 12.42.8 mm Hg, and postoperative lOP at 1 and 6mo were 11.6+2.5 and 12.0+2.8 mm Hg, respectively. After cataract surgery, angle parameters changed significantly while IOP significantly reduced and was maintained in group 2 (P〈0.001). The changes in angle parameters (&AOD500, ATISAS00 at temporal; &AOD500, S, RA500 at nasal) were linearly correlated with postoperative IOP changes. CONCLUSION: Cataract surgery may have improved antedor chamber angle parameters and decreased lOP in NTG patients. 展开更多
关键词 normal-tension glaucoma cataract surgery intraocular pressure reduction swept-source optical coherence tomography angle parameters
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Note on Entanglement of an Arbitrary State of Two Qubits
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作者 WANG An-Min 《Chinese Physics Letters》 SCIE CAS CSCD 2000年第4期243-245,共3页
It is shown that the norm of the polarization vector of the reduced density matrix can characterize the entangle ment of two qubits and so it is defined as a simple measure of entanglement. It is then extended to the ... It is shown that the norm of the polarization vector of the reduced density matrix can characterize the entangle ment of two qubits and so it is defined as a simple measure of entanglement. It is then extended to the generalized entanglement of polarization vector. It is proved that the entanglement of formation belongs to the generalized entanglement of polarization vector. Under the local general measurement and classical communication how this generalized entanglement of polarization vector changes is proved strictly and so the first and second laws of quantum information processing are verified clearly. 展开更多
关键词 vector. angle belongs
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Symmetry Violation of Time Reversal in Third Order Vertex Angle Renormalization Process of Electromagnetic Interaction
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作者 Xiaochun Mei 《Journal of Modern Physics》 2012年第1期43-47,共5页
According to the current understanding, electromagnetic interaction is invariable under time reversal. However, the proof of time reversal symmetry in quantum theory of field has not considered the effects of high ord... According to the current understanding, electromagnetic interaction is invariable under time reversal. However, the proof of time reversal symmetry in quantum theory of field has not considered the effects of high order perturbation normalizations. It is proved in the paper that when the renormalization effect of third order vertex angles process is taken into account, the symmetry of time reversal will be violated in electromagnetic interaction process. Because the magnitude order of symmetry violation is about 10–5, but the precision of current experiments on time reversal in particle physics is about 10–3, this kind of symmetry violation can not be found. The result reveals the micro-origin of asymmetry of time reversal and can be used to solve the famous irreversibility paradox in the evolution processes of macro- material systems. 展开更多
关键词 Quantum theory of Field SYMMETRY Time Reversal T VIOLATIONS normalization Vertex angle PROCESS
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Assessment on the Water Resources Carrying Capacity in Karst Area Based on the Cosine Vector Included Angle 被引量:5
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作者 袁子勇 焦树林 +1 位作者 杨萍 金开梅 《Meteorological and Environmental Research》 CAS 2010年第12期1-2,13,共3页
[Objective] The research aimed to assess the water resources carrying capacity in Guizhou Province based on the cosine vector included angle method. [Method] By using the cosine vector included angle method, the index... [Objective] The research aimed to assess the water resources carrying capacity in Guizhou Province based on the cosine vector included angle method. [Method] By using the cosine vector included angle method, the index weight was determined. The projection value of water resources carrying capacity in Guizhou Province was counted by using the multi-objective gray relational projection method. Moreover, the projection value which was counted by the index weight determined by the mean-variance method was as the control. [Result] The projection values which were obtained by two kinds of methods were very close, and the ordering result was consistent. [Conclusion] In the assessment of water resources carrying capacity, it was feasible to use the cosine vector included angle method to determine the index weight. 展开更多
关键词 Cosine vector included angle Index weight Gray relational projection Water resources carrying capacity China
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Prediction model for the initial seed clearing angles of a precision seed meter based on vector fields
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作者 Wan Jiao Junjie Zhang +3 位作者 Xuhui Chen Hao Shen Yuxiang Huang Jiangtao Shi 《International Journal of Agricultural and Biological Engineering》 SCIE 2024年第2期140-148,共9页
Seed clearing is a critical stage during precision seed metering process to ensure high seed singulation.However,there is a lack of understanding of the dynamics in the seed clearing process.In this study,a model was ... Seed clearing is a critical stage during precision seed metering process to ensure high seed singulation.However,there is a lack of understanding of the dynamics in the seed clearing process.In this study,a model was developed to predict initial seed clearing angle,in the seed clearing process using vector fields.The model was applied to an existing high-speed metering device and soybean seeds,and the model was evaluated with bench testing results.Results showed that dynamic changes in forces and constraints of seeds during the seed clearing process could be abstracted as vectors,and the changes of vector directions could be described by their phase angles.The phase angles were functions of the rotational angle of the seed meter.The phase angle of the constraint boundary linearly increases with the increase of the rotational angle.The phase angle of the force fluctuates,as the rotational angle changes.Initial seed clearing angle obtained from the phase angles varies from 8°to 59°,depending on the seeder travel speed.When comparing the values of the initial seed clearing angles predicted by the model with those from the bench tests,the root mean square error(RMSE)were from 2.73 to 3.14,and the correlation(r)between predict and observer were all higher than 0.98,indicating that the model had reasonably good accuracy. 展开更多
关键词 mechanical precision seeder initial seed clearing angle prediction model vector fields high-speed photography technology
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Normal tension glaucoma: from the brain to the eye or the inverse? 被引量:6
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作者 Hui-Jun Zhang Xue-Song Mi Kwok-Fai So 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第11期1845-1850,共6页
Glaucoma is a chronic, progressive optic neuropathy characterized by the loss of peripheral vision first and then central vision. Clinically, normal tension glaucoma is considered a special subtype of glaucoma, in whi... Glaucoma is a chronic, progressive optic neuropathy characterized by the loss of peripheral vision first and then central vision. Clinically, normal tension glaucoma is considered a special subtype of glaucoma, in which the patient’s intraocular pressure is within the normal range, but the patient experiences typical glaucomatous changes. However, increasing evidence has challenged the traditional pathophysiological view of normal tension glaucoma, which is based only on intraocular pressure, and breakthroughs in central nervous system imaging may now greatly increase our knowledge about the mechanisms underlying normal tension glaucoma. In this article, we review the latest progress in understanding the pathogenesis of normal tension glaucoma and in developing imaging techniques to detect it, to strengthen the appreciation for the connection between normal tension glaucoma and the brain. 展开更多
关键词 NERVE REGENERATION normal tension GLAUCOMA open angle GLAUCOMA NEURODEGENERATIVE diseases visual field CEREBROSPINAL fluid pressure IMAGING techniques pathogenesis magnetic resonance IMAGING diffusion tensor IMAGING metabolic changes neural REGENERATION
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Effect of bolt inclination angle on shear behavior ofbolted joints under CNL and CNS conditions 被引量:12
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作者 CUI Guo-jian ZHANG Chuan-qing +3 位作者 CHEN Jian-lin YANG Fan-jie ZHOU Hui LU Jing-jing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第3期937-950,共14页
Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting perfo... Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting performance.In this study,a new artificial molding method based on 3D scanning and printing technology was first proposed to prepare bolted joints with an inclined bolt.Then,the effects of the bolt inclination angle and boundary conditions on the shear behavior and failure characteristic of bolted joints were addressed by conducting direct shear tests under both CNL and CNS conditions.Results indicated that rock bolt could significantly improve the shear behavior of rock joints,especially in the post-yield deformation region.With the increase of bolt inclination angle,both the maximum shear stress and the maximum friction coefficient increased first and then decreased,while the maximum normal displacement decreased monotonously.Compared with CNL conditions,the maximum shear stress was larger,whereas the maximum normal displacement and friction coefficient were smaller under the CNS conditions.Furthermore,more asperity damage was observed under the CNS conditions due to the increased normal stress on the shear plane. 展开更多
关键词 bolted joints bolt inclination angle constant normal load(CNL)boundary conditions constant normal stiffness(CNS)boundary conditions direct shear test asperity damage
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Wind rotation characteristics of the upper tropospheric monsoon over the central and eastern tropical Pacific
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作者 LOU Pan-Xing LI Jian-Ping +2 位作者 FENG Juan ZHAO sen LIYan-Jie 《Atmospheric and Oceanic Science Letters》 CSCD 2016年第6期479-486,共8页
In this study, to investigate whether the variation of wind direction in the upper tropospheric monsoon over the central and eastern tropical Pacific shows similar characteristics to the classical monsoon region, the ... In this study, to investigate whether the variation of wind direction in the upper tropospheric monsoon over the central and eastern tropical Pacific shows similar characteristics to the classical monsoon region, the authors introduced a wind vector angle methodology that describes the size of the angle of the wind direction variation, as well as the directed rotary angle, which includes not only the size of the angle but also how the wind vector rotates. On this basis, the authors utilized and improved the directed rotary angle methodology to investigate the evolution of wind direction in detail, and the study confirmed the presence of the same four rotation features in the upper tropospheric monsoon region. Furthermore, the authors also identified the precise variation of wind direction in pentads with seasonal evolution, and found the onset time of the upper tropospheric monsoon may be earlier than the classical monsoon while the termination time may be later. The results further support and supplement the theory of global monsoons, which unifies the low-level and upper tropospheric monsoon as one monsoon system. 展开更多
关键词 Wind direction wind vector angle directed rotary angle upper tropospheric monsoon
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Local integrable differential systems and their normal forms
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作者 Shiliang Weng Xiang Zhang 《上海师范大学学报(自然科学版)》 2014年第5期476-485,共10页
In this paper we first summarize our results published in recent years and their sketch proofs on local integrability,which are on the characterization of local integrability and on the existence of analytic normaliza... In this paper we first summarize our results published in recent years and their sketch proofs on local integrability,which are on the characterization of local integrability and on the existence of analytic normalization of analytically integrable differential systems. Then we present a new result on the equivalent characterization of the existence of the first integrals of an analytic differential systems near a nonhyperbolic singularity. Finally we pose some open problems on this subject. 展开更多
关键词 formal diffeomorphism embedding vector field normal form
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Changes in segment coordination variability and the impacts of the lower limb across running mileages in half marathons:Implications for running injuries
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作者 Tony Lin-Wei Chen Duo Wai-Chi Wong +3 位作者 Yan Wang Qitao Tan Wing-Kai Lam Ming Zhang 《Journal of Sport and Health Science》 SCIE 2022年第1期67-74,共8页
Background:Segment coordination variability(CV)is a movement pattern associated with running-related injuries.It can also be adversely affected by a prolonged run.However,research on this topic is currently limited.Th... Background:Segment coordination variability(CV)is a movement pattern associated with running-related injuries.It can also be adversely affected by a prolonged run.However,research on this topic is currently limited.The purpose of this study was to investigate the effects of a prolonged run on segment CV and vertical loading rates during a treadmill half marathon.Methods:Fifteen healthy runners ran a half marathon on an instrumental treadmill in a biomechanical laboratory.Synchronized kinematic and kinetic data were collected every 2 km(from 2 km until 20 km),and the data were processed by musculoskeletal modeling.Segment CVs were computed from the angle-angle plots of selected pelvis-thigh,thigh-shank,and shank-rearfoot couplings using a modified vector coding technique.The loading rate of vertical ground reaction force was also calculated.A one-way MANOVA with repeated measures was performed on each of the outcome variables to examine the main effect of running mileage.Results:Significant effects of running mileage were found on segment CVs(p≤0.010)but not on loading rate(p=0.881).Notably,during the early stance phase,the CV of pelvis frontal thigh frontal was significantly increased at 20 km compared with the CV at 8 km(g=0.59,p=0.022).The CV of shank transverse vs.rearfoot frontal decreased from 2 km to 8 km(g=0.30,p=0.020)but then significantly increased at both 18 km(g=0.05,p<0.001)and 20 km(g=0.36,p<0.001).Conclusion:At the early stance,runners maintained stable CVs on the sagittal plane,which could explain the unchanged loading rate throughout the half marathon.However,increased CVs on the frontal/transverse plane may be an early sign of fatigue and indicative of possible injury risk.Further studies are necessary for conclusive statements in this regard. 展开更多
关键词 Coupling angle Endurance running Motion capture analysis Musculoskeletal modeling Vector coding technique
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On the basis of the morphology of the T-wave alternans: A Poincare mapping method research
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作者 Hui Guo Jie Zhao +1 位作者 Fei Li Tiantian Li 《Journal of Biomedical Science and Engineering》 2013年第4期504-507,共4页
Presently T-wave alternans (TWA) has become a clinical index of non-invasive diagnosis for heart sudden death prediction, and detecting T-wave alternate accurately is particularly important. This paper introduces an a... Presently T-wave alternans (TWA) has become a clinical index of non-invasive diagnosis for heart sudden death prediction, and detecting T-wave alternate accurately is particularly important. This paper introduces an algorithm for detecting TWA using Poincare mapping method which is a technique for nonlinear dynamic systems to display periodic behavior. Sample series of beat to beat cycles were selected to prepare Poincare mapping method. Vector Angle Index (VAI), which is the mean of the difference between θi (the angle between the line connecting the i point to the origin and the X axis) and 45 degrees was used to present the presence or absence of TWA. The value of 0.9 rad ≤ VAI ≤ 1.03 rad is accepted as a level determinative for presence of TWA. VAI via Poincare mapping method (PM) is used for correlation analysis with T-wave alternans voltage (Vtwa) by way of the spectral method (SM). The cross-correlation coefficient between Vtwa and VAI is γ = 0.8601. The algorithm can identify the absence and presence of TWA accurately and provide idea for further study of TWA-PM. 展开更多
关键词 T-WAVE ALTERNANS POINCARE Mapping METHOD Spectral METHOD Vector angle Index (VAI)
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The Representation of a Broadband Vector Field
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作者 任群 Jean Pierre Hermand 朴胜春 《Journal of Marine Science and Application》 2011年第4期495-501,共7页
Compared to a scalar pressure sensor, a vector sensor can provide a higher signal-to-noise ratio (SNR) signal and more detailed intbrmation on the sound field. Study on vector sensors and their applications have bec... Compared to a scalar pressure sensor, a vector sensor can provide a higher signal-to-noise ratio (SNR) signal and more detailed intbrmation on the sound field. Study on vector sensors and their applications have become a hot topic. Research on the representation of a vector field is highly relevant for extending the scope of vector sensor technology. This paper discusses the range-frequency distribution of the vector field due to a broadband acoustic source moving in a shallow-water waveguide as the self noise of a surface ship, and the vector extension of the waveguide impulse response measured over a limited frequency range using an active source of known waveform. From theory analysis and numerical simulation, the range-frequency representation of a vector field exhibits an interference structure qualitatively similar to that of the corresponding pressure field but, being quantitatively different, provides additional information on the waveguide, especially through the vertical component. For the range-frequency representation, physical quantities that can better exhibit the interference characteristics of the wavegaide are the products of pressure and particle velocity and of the pressure and pressure gradient. An image processing method to effectively detect and isolate the individual striations from an interference structure was reviewed briefly. The representation of the vector impulse response was discussed according to two different measurement systems, also known as particle velocity and pressure gradient. The vector impulse response representation can not only provide additional information from pressure only but even more than that of the range-frequency representation. 展开更多
关键词 acoustic waveguide vector field range-frequency interference structure striation processing impulse response normal mode
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The Connection of Vegetation with Tourism Development and Economic Growth: A Case Study for Aruba
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作者 Marck Oduber Jorge Ridderstaat Pim Martens 《Journal of Environmental Science and Engineering(A)》 2015年第8期420-431,共12页
Vegetation is an important ecosystem on earth. It influences the earth system in many ways. Any influences on this fragile variable should be investigated, especially in a changing climate. Humans can have a positive ... Vegetation is an important ecosystem on earth. It influences the earth system in many ways. Any influences on this fragile variable should be investigated, especially in a changing climate. Humans can have a positive or a negative influence on plants. This paper investigates the possible impact of tourism development and economic growth on vegetation health using cointegration and causality for Aruba. The proposed framework contributes to a better understanding on the use of remote sensing of vegetation response to tourism development and economic growth. Thereby, provide opportunities for improving the overall strategy for achieving sustainable development on a small island state. The calculations showed that there were relationships between the tourism demand and economic growth on the vegetation health on Aruba for the western part of the island. On the other hand, for the central part of the island, no relationships were found. 展开更多
关键词 normalized difference vegetation index tourism development vector error correction model vector autoregressive model small island Aruba.
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Mathematical Modeling of Shear Stress and Direct Shear Test for Compressible Soil: Case of Soil Bordering the Wouri River
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作者 Michael Soup Teoua Ouagni François Ngapgue +2 位作者 Fabien Kenmogne Alain Soup Tewa Kammogne Simon Ngoh Koumi 《World Journal of Engineering and Technology》 2021年第3期385-406,共22页
This paper focuses on the development of the mathematical model of shear stress by direct shear test for compressible soil of the littoral region, which will be a great tool in the hand of geotechnical engineers. The ... This paper focuses on the development of the mathematical model of shear stress by direct shear test for compressible soil of the littoral region, which will be a great tool in the hand of geotechnical engineers. The most common use of a shear test is to determine the shear strength which is the maximum shear stress that a material can withstand before the failure occurs. This parameter is useful in many engineering designs such as foundations, roads and retaining walls. We carried out an experimental laboratory test of ten samples of undisturbed soil taken at different points of the border of Wouri river of Cameroon. The samples were collected at different depths and a direct shear test was conducted. The investigations have been performed under constant vertical stresses and constant sample volume with the aim to determine the frictional angle and the cohesion of the compressible soil which are so important to establish the conditions of buildings stability. Special care was taken to derive loading conditions actually existing in the ground and to duplicate them in the laboratory. Given that the buildings constructed in this area are subjected to settlement, landslide, and punch break or shear failure, the cohesion and the frictional angle are determined through the rupture line after assessed the mean values of the shear stress for the considered ten samples. The bearing capacity of the soil, which is the fundamental soil parameter, was calculated. From the laboratory experimental results, the least squared method was used to derive an approximated mathematical model of the shearing stress. Many optimizations methods were then considered to reach the best adjustment. 展开更多
关键词 Direct Shear Test normal and Critical Stresses Frictional angle Bearing Capacity Mathematical Model
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