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211.
M.L. Zhou S. Zhao H.Y. Wang C. Lin H.Y. Lu Y.R. Lu T. Tajima X.T. He C.E. Chen Y.Q. Gu X.Q. Yan 《The European physical journal. Special topics》2014,223(6):1031-1035
We demonstrate the instability-free ion acceleration regime by introducing laser control with two parallel circularly polarized laser pulses at an intensity of I = 6.8 × 1021?W/cm2, normally incident on a hydrogen foil. The special structure of the equivalent wave front of those two pulses, which contains Gaussian peaks in both sides and a concavity in the centre (2D), can suppress the transverse instabilities and hole boring effects to constrain a high density ion clump in the centre of the foil, leading to an acceleration over a long distance and gain above 1GeV/u for the ion bunches. 相似文献
212.
213.
In this paper, we present a quantitative sufficient condition for adiabatic approximation in PT-symmetric quantum mechanics, which yields that a state of the PT-symmetric quantum system at any time will remain approximately in the m-th eigenstate up to a multiplicative phase factor whenever it is initially in the m-th eigenstate of the Hamiltonian. In addition, we estimate the approximation errors by the distance and the fidelity between the exact solution and the adiabatic approximate solution to the time evolution equation, respectively. 相似文献
214.
An Error Analysis for the Finite Element Approximation to the Steady-State Poisson-Nernst-Planck Equations 下载免费PDF全文
Ying Yang & Benzhuo Lu 《advances in applied mathematics and mechanics.》2013,5(1):113-130
Poisson-Nernst-Planck
equations are a coupled system of nonlinear partial differential
equations consisting of the Nernst-Planck equation and
the electrostatic Poisson equation with delta distribution sources,
which describe the electrodiffusion of ions in a solvated
biomolecular system. In this paper, some error bounds for a piecewise
finite element approximation to this problem are derived. Several numerical
examples including biomolecular problems are shown to support our analysis. 相似文献
215.
直线导轨是数控技术的重要组成部件,它的精确程度非常重要。以MSP430单片机为核心,设计了一个直线导轨精确定位装置。此装置采用两相四线的ST57型步进电机和60CM的螺纹丝杆组成一个直线导轨组,选用M7128驱动器驱动步进电机,使用PWM波精确定位算法程序精确控制电机转速。MSP430的IO端口控制步进电机的正反转,使得步进电机带动螺纹丝杆转动,让滚动丝杠上的物体往复移动,并在电脑上显示当前位移值。试验证明,其定位精度为0.01cm,具有较高的可靠性和准确性,低成本,稳定性好。 相似文献
216.
Dao-Ming Lu 《International Journal of Theoretical Physics》2013,52(9):3057-3065
This paper discusses the entanglement dynamics of a coupled cavity quantum electrodynamics (CQED) setup, which comprises three two-level atoms resonantly interacting with three cavities that are coupled by two optical fibers. The influences of atom-cavity coupling constant on the entanglement between atoms and that between cavities are discussed. The results obtained from the numerical method show that the entanglement between non-adjacent atoms or that between adjacent cavities has a nonlinear relation with increasing of the atom-cavity coupling coefficient. On the other hand, the entanglement between non-adjacent cavities is strengthened and the entanglement between adjacent atoms is weakened with increasing of atom-cavity coupling constant. 相似文献
217.
Ge Zhang Yangping Wen Yuzhen Li Jingkun Xu Chaoqun Guo Baoyang Lu Danhua Zhu 《Journal of fluorescence》2013,23(5):1053-1063
A variety of carboxylates were recognized using poly(9-aminofluorene) (P9AF) in the HEPES buffer (pH 7.4), and a proposed possible mechanism was proposed as following. The intermolecular hydrogen bonding interactions resulted in electron transfer between P9AF and carboxylates. P9AF was facilely electrosynthesized in boron trifluoride diethyl etherate and could be used as an efficient fluorescent sensing material for the detection of AcO?. On binding to AcO?, fluorescence quenching of P9AF was demonstrated by a maximum 80 % reduction in the fluorescence intensity, while no obvious fluorescence change could be observed in the presence of some other common anions. Some different carboxylates could be recognized at different levels by P9AF. Substituent groups in carboxylates could affect the intermolecular interaction between carboxylates and P9AF. These could be explained by a possible mechanism that hydrogen bonding was the main way of intermolecular interactions between P9AF and carboxylates, which was further confirmed by absorption spectra monitoring and density functional calculations. The significant advantage of this strategy is that it does not require a prequenching procedure and the polymer can be used directly for analyte detection. 相似文献
218.
BP神经网络用于肝炎患者舌诊近红外光谱的研究 总被引:1,自引:0,他引:1
为了对肝炎患者进行快速无创检测,用BP人工神经网络(ANN)方法在健康人与肝炎患者之间对人体舌面近红外光谱的反射率的关系进行关联方面的研究。分别采集了健康人和肝炎患者的舌左边、舌右边、舌下左边络脉、舌下右边络脉以及舌尖各部位各25例受试者的光谱数据,构造了一个3层神经网络结构,将所采集的各光谱数据进行归一化反射率预处理后作为神经网络的输入,建立了BP神经网络模型,分别选取对应的各个部位的40例作为训练样本集,用剩下的10例未知的样本进行预测,各部位测试的结果其相对偏差均在0.2以下,分类正确率为100%,达到满意的预测精度。结果表明提出的BP神经网络用于光谱舌诊进行无创检测识别不同病证提供了重要的参考价值。 相似文献
219.
220.
HengYan Wang WenQiang Zheng NengKun Yu KeRen Li DaWei Lu Tao Xin Carson Li ZhengFeng Ji David Kribs Bei Zeng XinHua Peng JiangFeng Du 《中国科学:物理学 力学 天文学(英文版)》2016,59(10):100313
We investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography(AUPT) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate(/8 phase gate), and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity. 相似文献