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A LOW-REGULARITY FOURIER INTEGRATOR FOR THE DAVEY-STEWARTSON II SYSTEM WITH ALMOST MASS CONSERVATION
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作者 Cui NING Chenxi HAO Yaohong WANG 《Acta Mathematica Scientia》 SCIE CSCD 2024年第4期1536-1549,共14页
In this work,we propose a low-regularity Fourier integrator with almost mass conservation to solve the Davey-StewartsonⅡsystem(hyperbolic-elliptic case).Arbitrary order mass convergence could be achieved by the suita... In this work,we propose a low-regularity Fourier integrator with almost mass conservation to solve the Davey-StewartsonⅡsystem(hyperbolic-elliptic case).Arbitrary order mass convergence could be achieved by the suitable addition of correction terms,while keeping the first order accuracy in H~γ×H^(γ+1)for initial data in H^(γ+1)×H^(γ+1)withγ>1.The main theorem is that,up to some fixed time T,there exist constantsτ_(0)and C depending only on T and‖u‖_(L^(∞)((0,T);H^(γ+1)))such that,for any 0<τ≤τ_(0),we have that‖u(t_(n),·)-u^(n)‖H_γ≤C_(τ),‖v(t_(n),·)-v^(n)‖_(Hγ+1)≤C_(τ),where u^(n)and v^(n)denote the numerical solutions at t_(n)=nτ.Moreover,the mass of the numerical solution M(u^(n))satisfies that|M(u^(n))-M(u_0)|≤Cτ~5. 展开更多
关键词 Davey-StewartsonⅡsystem low-regularity exponential integrator first order accuracy mass conservation
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Astrocytes integrate time and space
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作者 Justin Lines 《Neural Regeneration Research》 SCIE CAS 2025年第2期467-468,共2页
Astrocytes read and react to synaptic transmission through tripartite synapses,where the binding of neurotransmitters onto astrocytic receptors triggers an increase in intracellular calcium.Recent investigations have ... Astrocytes read and react to synaptic transmission through tripartite synapses,where the binding of neurotransmitters onto astrocytic receptors triggers an increase in intracellular calcium.Recent investigations have revealed that astrocytes exhibit two distinct states of intracellular calcium activity:(1)graded subcellular localized clusters with independently active microdomains,likely influenced by nearby synaptic events,and(2)whole-cell astrocyte calcium surges,believed to result from the coordinated activation of multiple synapses.Notably,astrocyte calcium responses are not solely graded;instead,a spatial threshold of intracellular calcium activity can be overcome to elicit an astrocyte calcium surge.Together these calcium responses,in turn,initiate downstream signaling pathways capable of modifying synaptic communication and overall network activity.In summary,astrocytes can function as integrators of local synaptic events,actively contributing to information processing within the brain. 展开更多
关键词 GRADED integrATE instead
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Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review
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作者 Stiven Roytman Rebecca Paalanen +4 位作者 Giulia Carli Uros Marusic Prabesh Kanel Teus van Laar Nico I.Bohnen 《Neural Regeneration Research》 SCIE CAS 2025年第1期82-92,共11页
Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have ... Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population.Posture and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous mechanisms.To effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory signals.The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work.Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults.Insufficient emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance.In the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s disease.We also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older adults.Lastly,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases. 展开更多
关键词 aging BALANCE encephalography functional magnetic resonance imaging GAIT multisensory integration Parkinson’s disease positron emission tomography SOMATOSENSORY VESTIBULAR visual
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Cohort study on the treatment of BRAF V600E mutant metastatic colorectal cancer with integrated Chinese and western medicine
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作者 Jiang-Yu Bian Yu-Fang Feng +1 位作者 Wen-Ting He Tong Zhang 《World Journal of Clinical Oncology》 2025年第1期25-33,共9页
BACKGROUND Patients with BRAF V600E mutant metastatic colorectal cancer(mCRC)have a low incidence rate,poor biological activity,suboptimal response to conventional treatments,and a poor prognosis.In the previous cohor... BACKGROUND Patients with BRAF V600E mutant metastatic colorectal cancer(mCRC)have a low incidence rate,poor biological activity,suboptimal response to conventional treatments,and a poor prognosis.In the previous cohort study on mCRC conducted by our team,it was observed that integrated Chinese and Western medicine treatment could significantly prolong the overall survival(OS)of patients with colorectal cancer.Therefore,we further explored the survival benefits in the population with BRAF V600E mutant mCRC.AIM To evaluate the efficacy of integrated Chinese and Western medicine in the treatment of BRAF V600E mutant metastatic colorectal cancer.METHODS A cohort study was conducted on patients with BRAF V600E mutant metastatic colorectal cancer admitted to Xiyuan Hospital of China Academy of Chinese Medical Sciences and Traditional Chinese Medicine Hospital of Xinjiang Uygur Autonomous Region from January 2016 to December 2022.The patients were divided into two cohorts.RESULTS A total of 34 cases were included,with 23 in Chinese-Western medicine cohort(cohort A)and 11 in Western medicine cohort(cohort B).The median overall survival was 19.9 months in cohort A and 14.2 months in cohort B,with a statistically significant difference(P=0.038,hazard ratio=0.46).The 1-3-year survival rates were 95.65%(22/23),39.13%(9/23),and 26.09%(6/23)in cohort A,and 63.64%(7/11),18.18%(2/11),and 9.09%(1/11)in cohort B,respectively.Subgroup analysis showed statistically significant differences in median OS between the two cohorts in the right colon,liver metastasis,chemotherapy,and first-line treatment subgroups(P<0.05).CONCLUSION Integrated Chinese and Western medicine can prolong the survival and reduce the risk of death in patients with BRAF V600E mutant metastatic colorectal cancer,with more pronounced benefits observed in patients with right colon involvement,liver metastasis,combined chemotherapy,and first-line treatment. 展开更多
关键词 Metastatic colorectal cancer BRAF V600E mutation integrated Chinese and Western medicine Cohort study
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基于Cyber-Integrator语义平台的临床路径工作流管理方法研究 被引量:2
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作者 俞思伟 姜赢 董慧 《医学信息学杂志》 CAS 2010年第9期2-7,共6页
介绍一种基于Cyber-Integrator(CI)语义平台的临床路径(CP)工作流管理方法。阐明国内外语义技术在临床路径应用的成功案例,指出CP语义描述的可行性与不足,深入探讨如何利用CI语义平台来对CP工作流进行管理,包括描述、执行和控制等,说明... 介绍一种基于Cyber-Integrator(CI)语义平台的临床路径(CP)工作流管理方法。阐明国内外语义技术在临床路径应用的成功案例,指出CP语义描述的可行性与不足,深入探讨如何利用CI语义平台来对CP工作流进行管理,包括描述、执行和控制等,说明此方法局限性并提出进一步研究方向。 展开更多
关键词 临床路径 语义技术 Cyber—integrator RDF OWL
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Determination of aniline in environmental water samples by alternating-current oscillopolarographic titration 被引量:6
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作者 Jun Ping Xiao Qing Xiang Zhou +2 位作者 Xiao Ke Tian Hua Hua Bai Xian Fa Su 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第6期730-733,共4页
A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosa... A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail. The experimental results indicated that this method was simple, rapid, and sensitive. The linear range was 8.367 × 10(?4) to 2.789 × 10(?2) mol L(?1), the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4–106.9% under the optimal conditions. The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples. 展开更多
关键词 alternating-current oscillopolarographic titration ANILINE Potassium bromide
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基于ARM Integrator的Sigma-Delta音频DAC的实现
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作者 于芳玲 闫华 钟锐 《电子器件》 CAS 2007年第2期668-671,共4页
介绍了ARM公司的一款FPGA验证开发平台ARMIntegrator,以及基于该平台设计的Sigma-Delta音频DAC的实现.在详细介绍Integrator的各个模块的基础之上,利用开发平台的FPGA上验证实现了一个1阶的6位的Sigma-Delta型的DAC,主要包括Sigma-Delta... 介绍了ARM公司的一款FPGA验证开发平台ARMIntegrator,以及基于该平台设计的Sigma-Delta音频DAC的实现.在详细介绍Integrator的各个模块的基础之上,利用开发平台的FPGA上验证实现了一个1阶的6位的Sigma-Delta型的DAC,主要包括Sigma-Delta DAC的原理与主要电路,FPGA验证实现过程中的DAC数字滤波器以及调制器的设计以及验证流程,通过virsi m仿真时序波形,验证了所设计的DAC正确性和可实现性. 展开更多
关键词 ARM integrator SIGMA-DELTA 插值滤波器 DAC FPGA
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Geometric formulations and variational integrators of discrete autonomous Birkhoff systems 被引量:5
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作者 刘世兴 刘畅 郭永新 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第3期284-288,共5页
The variational integrators of autonomous Birkhoff systems are obtained by the discrete variational principle. The geometric structure of the discrete autonomous Birkhoff system is formulated. The discretization of ma... The variational integrators of autonomous Birkhoff systems are obtained by the discrete variational principle. The geometric structure of the discrete autonomous Birkhoff system is formulated. The discretization of mathematical pendulum shows that the discrete variational method is as effective as symplectic scheme for the autonomous Birkhoff systems. 展开更多
关键词 autonomous Birkhoff syetem discrete variational principle variational integrators
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Global satisfactory control for nonlinear integrator processes with long delay 被引量:4
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作者 Yiqun YANG Guobo XIANG 《控制理论与应用(英文版)》 EI 2007年第2期207-210,共4页
Integrator processes with long delay are difficult to control. Nonlinear characteristics of actuators make the control problem more challenging. A technique is proposed in this paper for global satisfactory control (... Integrator processes with long delay are difficult to control. Nonlinear characteristics of actuators make the control problem more challenging. A technique is proposed in this paper for global satisfactory control (GSC) of such processes with relay-type nonlinearity. An oscillatory control signal is injected into the nonlinear process; the amplitude and frequency of the oscillatory signal are designed to linearise the nonlinear process in the sense of harmonic analysis; and a state feedback controller is configured to implement GSC over the linearised process. An illustrative example is given to demonstrate the effectiveness of 展开更多
关键词 integrator processes Time delay Oscillation Harmonic linearisation Global satisfactory control
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Design of high-performance energy integrator detector for wideband radar 被引量:2
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作者 CHANG Jiayun FU Xiongjun +1 位作者 JIANG Wen XIE Min 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第6期1110-1118,共9页
Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance... Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance deterioration if the detection window is not selected properly. In this paper, an EI detector for the distributed targets in the Gaussian environment is proposed.First, at the stage of preparatory work, the target models are proposed, then, the problem formulation is introduced. Subsequently,in the aspect of optimizing the method of detection window search and the method of threshold setting, the detailed design stages of the proposed detector are provided. Furthermore, theoretical analyses show that the proposed detector is easy to hardware implementation, and it does not need the prior knowledge about the spatial distribution of the target scattering centers in practical radar detection application. Finally, the performance assessment conducted by Monte Carlo simulations verifies that the proposed detector outperforms the conventional detectors. 展开更多
关键词 RADAR detection distributed target integration detec tor.
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Improvement of Boxcar Integrator and Its Application to Low Resistance Measurement of Inductive Load Coil 被引量:2
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作者 Xisheng Li Shaochun Wang(Information Engineering School, University of Science and Technology Beijing, Beijing 100083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1998年第3期180-184,共5页
A boxcar integrator is described which is suitable for the low-repetition-rate signal processing. This boxcar integrator, named fixed-interval mode boxcar integrator, is able to reject harmonics other than the first h... A boxcar integrator is described which is suitable for the low-repetition-rate signal processing. This boxcar integrator, named fixed-interval mode boxcar integrator, is able to reject harmonics other than the first harmonic component. It can also decrease the effective time constant In many situations, the antialiasing filter with narrow bandwidth will cause distortion of the input signal. The fixed-interval mode boxcar integrator with suitable gate width can achieve relative high performance without signal distortion because the bandwidth of its antialiasing filter can be wider than that in the fixed-Point boxcar integrator. ms boxcar integrator is used as majn part of signalprocessing circult in the low resisance measurement of inductive load coil. The results of experiments show that the fixed-interval boxcar integrator is suitable for low-repetition-rate use. 展开更多
关键词 signal processing resistance measurement boxcar integrator
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Two New Fourth-Order Three-Stage Symplectic Integrators 被引量:3
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作者 LI Rong WU Xin 《Chinese Physics Letters》 SCIE CAS CSCD 2011年第7期1-4,共4页
Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and latticeφ4 model.When the nonintegrable l... Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and latticeφ4 model.When the nonintegrable latticeφ4 system is taken as a test model,numerical comparisons show that the new methods have a great advantage over the second-order Verlet symplectic integrators in the accuracy of energy,become explicitly better than the usual non-gradient fourth-order seven-stage symplectic integrator of Forest and Ruth,and are almost equivalent to a fourth-order seven-stage force gradient symplectic integrator of Chin.As the most important advantage,the new integrators are convenient for solving the variational equations of many Hamiltonian systems so as to save a great deal of the computational cost when scanning a lot of orbits for chaos. 展开更多
关键词 SYMPLECTIC HAMILTONIAN integrABLE
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Rapid determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration 被引量:1
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作者 XIAO Jun-ping WANG Xue-feng +4 位作者 ZHOU Qing-xiang FAN Xiao-yuan SU Xian-fa Bai Hua-hua DUAN Hai-jing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第5期622-627,共6页
A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol coul... A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol could be transferred into a nitroso-compound by reacting with NaNO2. The titration end-point was obtained by the formation of a sharp cut in the oscillopolarographic with infinitesimal NaNO2 on double platinum electrodes. The results showed that phenol had an excellent linear relationship over the range of 4.82×10^-6 -9.65×10^-3 mol/L, the RSD of the proposed method was lower than 1.5%, and the spiked recoveries of three real water samples were in the range of 95.6%-106.9%. 展开更多
关键词 alternating-current oscillopolarographic titration phenolic compounds
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PpARF6 acts as an integrator of auxin and ethylene signaling to promote fruit ripening in peach 被引量:2
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作者 Xiaomei Chen Yudi Liu +3 位作者 Xian Zhang Beibei Zheng Yuepeng Han Ruo-Xi Zhang 《Horticulture Research》 SCIE CSCD 2023年第9期151-164,共14页
Although auxin is known to induce ethylene biosynthesis in some Rosaceae fruit crops,the mechanisms underlying the auxin–ethylene interaction during fruit ripening remain largely unknown.Here,the regulatory role of a... Although auxin is known to induce ethylene biosynthesis in some Rosaceae fruit crops,the mechanisms underlying the auxin–ethylene interaction during fruit ripening remain largely unknown.Here,the regulatory role of an auxin response factor,PpARF6,in fruit ripening was investigated in peach.Peach fruits showed accelerated ripening after treatment with auxin and PpARF6 was found to be significantly induced.PpARF6 not only could induce ethylene synthesis by directly activating the transcription of ethylene biosynthetic genes,but also competed with EIN3-binding F-box proteins PpEBF1/2 for binding to ethylene-insensitive3-like proteins PpEIL2/3,thereby keeping PpEIL2/3 active.Moreover,PpARF6 showed an interaction with PpEIL2/3 to enhance the PpEIL2/3-activated transcription of ethylene biosynthetic genes.Additionally,ectopic overexpression of PpARF6 in tomato accelerated fruit ripening by promoting the expression of genes involved in ethylene synthesis and fruit texture.In summary,our results revealed a positive regulatory role of PpARF6 in peach fruit ripening via integrating auxin and ethylene signaling. 展开更多
关键词 INTERACTION integrating thereby
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Symplectic-energy-first integrators of discrete mechanico-electrical dynamical systems 被引量:1
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作者 傅景礼 陈本永 +1 位作者 唐贻发 付昊 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第11期3942-3952,共11页
A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplec... A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplectic-energy-first integrators for mechanico-electrical systems are derived. To do this, the time step adaptation is employed. The discrete variational principle and the Euler-Lagrange equation are derived for the systems. By using this discrete algorithm it is shown that mechanico-electrical systems are not symplectic and their energies are not conserved unless they are Lagrange mechanico-electrical systems. A practical example is presented to illustrate these results. 展开更多
关键词 total variation symplectic-energy-momentum integrator mechanico-electrical system
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Experimental design to measure the anchoring energy on substrate surface by using the alternating-current bridge 被引量:1
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作者 郝慧明 刘瑶瑶 +4 位作者 张平 蔡明雷 王晓燕 朱吉亮 叶文江 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第8期315-319,共5页
The anchoring property of the substrate surface of liquid crystal cells plays an important role in display and nondisplay fields. This property directly affects the deformation of liquid crystal molecules to change th... The anchoring property of the substrate surface of liquid crystal cells plays an important role in display and nondisplay fields. This property directly affects the deformation of liquid crystal molecules to change the phase difference through liquid crystal cells. In this paper, a test method based on the alternating-current bridge is proposed to determine the capacitance of liquid crystal cells and thus measure the anchoring energy of the substrate surface. The anchoring energy can be obtained by comparing the capacitance-voltage curves of twisted nematic liquid crystal cells with different anchoring properties in experimental and theoretical results simulated on the basis of Frank elastic theory. Compared with the other methods to determine the anchoring energy, our proposed method requires a simple treatment of liquid crystal cells and allows easy and high-accuracy measurements, thereby expanding the test ideas on the performance parameters of liquid crystal devices. 展开更多
关键词 anchoring energy alternating-current bridge capacitance of liquid crystal cell twisted nematic
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A new dimmer for alternating-current directly driven light-emitting-diode lamp 被引量:1
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作者 KIM Jong-hyun RYU Myung-hyo +1 位作者 YOON Hyok-min SONG Eui-ho 《Journal of Central South University》 SCIE EI CAS 2012年第2期374-379,共6页
A new dimmer using a mental-oxide-semiconductor field-effect transistor (MOSFET) for alternating-current (AC) directly driven light-emitting-diode (LED) lamp was presented. The control method of proposed dimmer is pul... A new dimmer using a mental-oxide-semiconductor field-effect transistor (MOSFET) for alternating-current (AC) directly driven light-emitting-diode (LED) lamp was presented. The control method of proposed dimmer is pulse width control (PWM) method. Compared with the conventional phase-controlled dimmer, the proposed PWM dimmer can produce sine wave and did not cause harmonics problem. Furthermore, the proposed control method did not amplify the light flicker due to the independence of input voltage. Therefore, the PWM dimmer can be used as the dimmer of the AC LED lamp instead of the conventional phase-controlled dimmer. The experimental result shows that the proposed PWM dimmer has good performances. 展开更多
关键词 alternating-current directly driven light-emitting-diode pulse width control total harmonic distortion flicker triac
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Alternating-current losses in two-layer superconducting cables consisting of second-generation superconductors coated by U-shaped ferromagnetic materials 被引量:1
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作者 Ahmet Cicek Fedai Inanir Fedor Gmry 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期509-513,共5页
Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by eithe... Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by either a non-magnetic or strong ferromagnetic material having a U profile is numerically investigated. Computations are carried out through the finite-element method. The alternating-current losses do not increase significantly if the relative permeability of the coating is increased three orders of magnitude, provided that the current amplitude is less than half of the critical current in a superconducting wire. However, the losses are much higher for ferromagnetic coating if the amplitude of the applied current oscillating at 50 Hz is close to the critical current. The ferromagnetic coating is seen to accumulate the magnetic field lines normally on its surfaces, while the field lines are parallel to the long axes of the wires, leading to more significant flux penetration in the coated regions. This facilitates a uniform low-loss current flow in the uncoated regions of the wires. In contrast, coating with a non-magnetic material gives rise to a considerably smaller current flow in the uncoated regions, whereas the low-loss flow is maintained in the coated regions. Moreover, the current flows in opposite directions in the coated and uncoated regions, where the direction in each region is converse for the two materials. 展开更多
关键词 second-generation superconductor two-layer cable ferromagnetic coating U profile alternating-current losses
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On Trigonometric Numerical Integrator for Solving First Order Ordinary Differential Equation 被引量:1
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作者 A. A. Obayomi S. O. Ayinde O. M. Ogunmiloro 《Journal of Applied Mathematics and Physics》 2019年第11期2564-2578,共15页
In this paper, we used an interpolation function with strong trigonometric components to derive a numerical integrator that can be used for solving first order initial value problems in ordinary differential equation.... In this paper, we used an interpolation function with strong trigonometric components to derive a numerical integrator that can be used for solving first order initial value problems in ordinary differential equation. This numerical integrator has been tested for desirable qualities like stability, convergence and consistency. The discrete models have been used for a numerical experiment which makes us conclude that the schemes are suitable for the solution of first order ordinary differential equation. 展开更多
关键词 NUMERICAL integrator Ordinary Differential Equation INITIAL Value Problems Stability Analysis NONSTANDARD METHODS INTERPOLATION METHODS
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Chebyshev spectral variational integrator and applications 被引量:2
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作者 Zhonggui YI Baozeng YUE Mingle DENG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第5期753-768,共16页
The Chebyshev spectral variational integrator(CSVI) is presented in this paper. Spectral methods have aroused great interest in approximating numerically a smooth problem for their attractive geometric convergence rat... The Chebyshev spectral variational integrator(CSVI) is presented in this paper. Spectral methods have aroused great interest in approximating numerically a smooth problem for their attractive geometric convergence rates. The geometric numerical methods are praised for their excellent long-time geometric structure-preserving properties.According to the generalized Galerkin framework, we combine two methods together to construct a variational integrator, which captures the merits of both methods. Since the interpolating points of the variational integrator are chosen as the Chebyshev points,the integration of Lagrangian can be approximated by the Clenshaw-Curtis quadrature rule, and the barycentric Lagrange interpolation is presented to substitute for the classic Lagrange interpolation in the approximation of configuration variables and the corresponding derivatives. The numerical float errors of the first-order spectral differentiation matrix can be alleviated by using a trigonometric identity especially when the number of Chebyshev points is large. Furthermore, the spectral variational integrator(SVI) constructed by the Gauss-Legendre quadrature rule and the multi-interval spectral method are carried out to compare with the CSVI, and the interesting kink phenomena for the Clenshaw-Curtis quadrature rule are discovered. The numerical results reveal that the CSVI has an advantage on the computing time over the whole progress and a higher accuracy than the SVI before the kink position. The effectiveness of the proposed method is demonstrated and verified perfectly through the numerical simulations for several classical mechanics examples and the orbital propagation for the planet systems and the Solar system. 展开更多
关键词 geometric numerical method spectral method variational integrator Clenshaw-Curtis quadrature rule barycentric Lagrange interpolation orbital propagation
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