Cytoplasmic Ca2＋ Dynamics under the Interplay between the Different IP3R Gating Models and the Plasma Membrane Ca2＋ Influx

The cytoplasmic Ca2＋ oscillations are investigated under the effect of CRAC channels in non-excitable cells （especially in T cells）. The oscillatory Ca2＋ signals can be modulated as the amplitude-, frequency- and mixed amplitude-frequency modulation modes dependent on the different IP3R gating models. Bifurcation analyses show that Ca2＋ signals in the single positive feedback loop model is a mixed modulation mode. In contrast, Ca2＋ signals in the Mak-McBride-Foskett model demonstrates approximately the frequency modulation mode only with slight amplitude shifts.     

FM-AM Conversion Induced by Polarization Mode Dispersion in Fiber Systems

The conversion of the frequency modulated pulse induced from frequency modulation （FM） to amplitude modulation （AM） by the polarization mode dispersion （PMD） is theoretically and experimentally investigated. When there is no polarizer at the output end of a fiber system, the amplitude modulation depth is stable by 8%. Random amplitude modulation is observed when a polarizer is placed at the output end of the fiber system. The observed minimum and maximum modulation depths in our experiment are 5% and 80%, respectively. Simulation results show that the amplitude modulation is stable by 4% induced mainly by group velocity dispersion （GVD） when there is no polarizer, and the amplitude modulation depth displays the random variation character induced by the GVD and PMD. Lastly, a new fiber system scheme is proposed and little amplitude modulation is observed at the top of the output pulse.     

Numerical Simulations of Calcium Ions Spiral Wave in Single Cardiac Myocyte

The calcium ions （Ca^2＋） spark is an elementary Ca^2＋ release event in cardiac myocytes. It is believed to buildup cell-wide Ca^2＋ signals, such as Ca^2＋ transient and Ca^2＋ wave, through a Ca^2＋-induced Ca^2＋ release （CICR） mechanism. Here the excitability of the Ca^2＋ wave in a single cardiac myoeyte is simulated by employing the fire-diffuse-fire model. By modulating the dynamic parameters of Ca^2＋ release and re-uptake channels, we find three Ca^2＋ signaling states in a single cardiac myoeyte： no wave, plane wave, and spiral wave. The period of a spiral wave is variable in the different regimes. This study indicates that the spiral wave or the excitability of the system can be controlled through micro-modulation in a living excitable medium.     

Mechanism of the excitation of single pure mode L（0, 2） and its interaction with the defect in a hollow cylinder

Guided elastic waves have a great potential in pipe inspection as an efficient and low-cost nondestructive evaluation （NDE） technique, among which the wave of mode L（0, 2） receives a lot of attention because this mode is the fastest mode in a weakly dispersive region of frequency to minimize dispersion effects over a long distance and sensitive to the defects distributed circumferentially. Though many experimental and numerical researches have already been carried out about the excitation of L（0, 2） and its interaction with the defect in a hollow cylinder, its excitation mechanism has not been clarified yet. In this paper based on the transient response solution of the hollow cylinder, derived by the method of eigenfunction expansion, the theory about the exciting mechanism of mode L（0, 2） is advanced and the effects of the spatial distribution, vibration frequency and direction of the external force on the excitation are discussed. And the pure mode L（0, 2） is excited successfully under the parameters obtained through theoretical analysis. Furthermore, its interactions with some kinds of defects in hollow cylinders are simulated with the method of finite element analysis （FEA） and the results agree well with those obtained by other researchers.     

Stationary patterns in a discrete bistable reaction--diffusion system: mode analysis

This paper theoretically analyses and studies stationary patterns in diffusively coupled bistable elements. Since these stationary patterns consist of two types of stationary mode structure: kink and pulse, a mode analysis method is proposed to approximate the solutions of these localized basic modes and to analyse their stabilities. Using this method, it reconstructs the whole stationary patterns. The cellular mode structures (kink and pulse) in bistable media fundamentally differ from stationary patterns in monostable media showing spatial periodicity induced by a diffusive Turing bifurcation.     

Multimode resonance bandpass filter with twin wideband channels

A bandpass filter with twin wideband channels in a single-layer guided-mode resonance grating is presented.Strong refractive-index modulation is used to support the excitation of multimode resonances TE1,0,TE1,1,TE2,0,TE1,2,and TE2,1,which are excited by the first and second diffraction orders,relate asymmetrical line shapes and broad low-transmission bands,where TE is the transverse electric.Taking advantage of narrow linewidth and sharp edge line shape in the spectra of TE2,υ(v is the mode),a bandpass filter with form factors of 0.61 and 0.7 for long-and short-wave channels is presented to demonstrate this concept.     

Modulation properties of spatial three-waveguide system using weakly coupled mode theory

Based on the weakly coupled mode theory, the modulation properties of three-waveguide system are analyzed in general. We examine the modulation behavior for two cases that a voltage is applied on the beam-launched waveguide or non-beam-launched waveguide. The analytical intensity distributions in both cases are given. Applications of the spatial multi-waveguide coupling systems include spatial light modulators, optical switches, optical interconnection, and spatial optical signal processing.     

Wavelength modulation spectroscopy based on quasi-continuous-wave diode lasers

A modified wavelength modulation spectroscopy（WMS）based on the self-heating effect of the tunable diode laser when driven in quasi-continuous-wave（QCW）mode is investigated.A near-infrared distributed feedback（DFB）diode laser working at the QCW mode is employed as the QCW light source,and CO2 is selected as the target gas.The characteristic of the QCW second harmonic（2f）line profile is analyzed through a comparison with that of the traditional CW WMS with the same system.A noise-equivalent absorbance of 3.2×10-5 Hz-1/2 for CO2 at 1.58μm is obtained with 18-m optical path.The QCW WMS lowers the dependence on lasers and expands selectivity,thus verifying the feasibility of the method.     

Pre-pumped passively Q-switched Nd:YAG/Cr:YAG microchip laser

A pre-pumped passively Q-switched Nd:YAG/Cr: YAG microchip laser is demonstrated with a peak power of 7.5 kW at pulse repetition rate of serveral kilohertzs. The full-width at half-maximum (FWHM) is 734 ps, and the pulse energy is 5.5 μJ with a fundamental spatial mode. In this system, the pre-pumped microchip laser of Nd: YAG/Cr: YAG wafer which is bonded through the thermal-bonding technique has achieved a time jitter value of 12 μs and a Q-switched amplitude instability of 1.26% (1δ) through the pre-pumped modulation technique.     

Synchronized Anti-Phase and In-Phase Oscillations of Intracellular Calcium Ions in Two Coupled Hepatocytes System

We study the dynamic behaviour of two intracellufar calcium oscillators that are coupled through gap junctions both to Ca^2＋ and inositol（1,4,5）-trisphosphate （IP3）. It is found that synchronized anti-phase and in-phase oscillations of cytoplasmic cadcium coexist in parameters space. Especially, synchronized anti-phase oscillations only occur near the onset of a Hopf bifurcation point when the velocity of IP3 synthesis is increased. In addition, two kinds of coupling effects, i.e., the diffusions of Ca^2＋ and IP3 among cells on synchronous behaviour, are considered. We fnd that small coupling of Ca^2＋ and large coupling of IP3 facilitate the emergence of synchronized anti-phase oscillations. However, the result is contrary for the synchronized in-phase case. Our findings may provide a qualitative understanding about the mechanism of synchronous behaviour of intercellular calcium signalling.     

Numerical simulation and analysis of complex patterns in a two-layer coupled reaction diffusion system

The resonance interaction between two modes is investigated using a two-layer coupled Brusselator model. When two different wavelength modes satisfy resonance conditions, new modes will appear, and a variety of superlattice patterns can be obtained in a short wavelength mode subsystem. We find that even though the wavenumbers of two Turing modes are fixed, the parameter changes have influences on wave intensity and pattern selection. When a hexagon pattern occurs in the short wavelength mode layer and a stripe pattern appears in the long wavelength mode layer, the Hopf instability may happen in a nonlinearly coupled model, and twinkling-eye hexagon and travelling hexagon patterns will be obtained. The symmetries of patterns resulting from the coupled modes may be different from those of their parents, such as the cluster hexagon pattern and square pattern. With the increase of perturbation and coupling intensity, the nonlinear system will convert between a static pattern and a dynamic pattern when the Turing instability and Hopf instability happen in the nonlinear system. Besides the wavenumber ratio and intensity ratio of the two different wavelength Turing modes, perturbation and coupling intensity play an important role in the pattern formation and selection. According to the simulation results, we find that two modes with different symmetries can also be in the spatial resonance under certain conditions, and complex patterns appear in the two-layer coupled reaction diffusion systems.     

Central distance of interferential mode patterns of elliptical core two-mode fiber

By means of the weakly guiding approximation, the mode spot sizes Wx and Wy of the fundamental mode along the semimajor （x-direction） and semiminor （y-direction） axes of the fiber core in elliptical core two- mode fiber are discussed. The variation of their ratio value Wx/W9 with the operation wavelength A and the length ratio a/b between the semimajor axis and the semiminor axis of the fiber core is analyzed. Based on this analysis, the distribution figures of two-lobe interferential mode patterns are evaluated and simulated quantitatively for different phase difference changes between LP01 and LP~~n modes. The two-lobe interferential mode patterns have the same profile and distribute symmetrically when the phase difference equals ~r/2. Their central distance S becomes larger when W~：/W~ augments gradually. F~rthermore, the equation about the central distance S of the two-lobe interferential mode patterns is given when the operation wavelength varies between 0.65 and 1.31 #m, which is important to applications shuch as sensors and coupling devices between different fibers.     

The WKBZ mode approach to pulsed propagation in ocean channels

In the paper, the WKBZ normal mode approach has been applied to the propagation of the pulsed energy and waveform in ocean channels. The numerical results in two different channels are given. Comparison between the WKBZ and conventional normal mode codes shows that the WKBZ mode approach is a fast and accurate method and the running time by the WKBZ approach is reduced by about two orders of magnitude.     

Dissociative ionization cross sections of CO2 at electron impact energy of 5 keV

The dissociative ionization of CO2 induced by 5 keV electrons in two-body and three-body dissociative channels of CO2＋2 and CO3＋2 is identified by the ion-ion coincidence- method using a momentum imaging spectrometer. The partial ionization cross sections （PICSs） of different ionic fragments are measured and the results generally agree with the calculations made by a semi-empirical approach. Furthermore, the PICSs of the dissociative channels are also obtained by carefully considering the detection efficiency of the micro-channel plates and the total transmission efficiency of the time of flight system.     

Equivalence of MTF of a turbid medium and radiative transfer field

The equivalence of the modulation transfer function (MTF) of a turbid medium and the transmitted radiance from the medium under isotropic diffuse illumination is demonstrated. MTF of a turbid medium can be fully evaluated by numerically solving a radiative transfer problem in a plane parallel medium. MTF for a homogenous single layer turbid medium is investigated as illustration. General features of the MTF in the low and high spatial frequency domains are provided through their dependence on optical thickness, single scattering albedo, asymmetrical factor, and phase function type.     

Abnormal Modulation of Dielectric Band Transmittance of Polystyrene Opal

The abnormal transmittance in the dielectric band edge of a polystyrene opal is observed and analysed. The transmittance is periodically modulated and the period of modulation varies with the wavelength, which destroys the perfect structure of the photonic band gap. The transmittance modulation originates from the propagation of the low order whispering-gallery mode excited in polystyrene spheres. These results indicate that the whisperinggallery mode has a great influence on practical applications of polystyrene opal.     

Wavelength Modulation Absorption Spectroscopy Using a Frequency-Quadruped Current-Modulated System

A wavelength modulation absorption spectrometry （WMAS） with a frequency-quadruped system is demonstrated. The frequency-quadruped system consists of a two-frequency doubled external enhancement cavity with KNO3 and BBO crystals, and a current-modulated 906-nm single mode external cavity diode laser （ECDL）, which generates the tunable wavelength modulated radiation at 226.7nm used to detect the NO absorption line that belongs to the combined Q22（10.5） and QR12（10.5） lines of γ（0,0） band within the A^2∑^＋ -X^2II electronic transition system. The 1^st, 2^nd and 3^rd harmonic spectra are accomplished to show that it is possible to detect samples using the frequency quadruped system combined with the WMAS technique that can find practical applicability in the future.     

Control of firing activities in thermosensitive neuron by activating excitatory autapse

Temperature has distinct influence on the activation of ion channels and the excitability of neurons, and careful change in temperature can induce possible mode transition in the neural activities. The formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus, and thus the firing patterns in neuron can be controlled effectively. The autapse is activated to drive a thermosensitive neuron, which is developed from the FitzHugh–Nagumo neural circuit by incorporating a thermistor, and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic current. It is found that the firing modes can be controlled by temperature, and the neuron is wakened from resting state to periodic oscillation with the increase of temperature. Furthermore, the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities, and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.     

Sub-pixel processing for super-resolution scanning imaging system with fiber bundle coupling

A multilayer fiber bundle is used to couple the image in a remote sensing imaging system.The object image passes through all layers of the fiber bundle in micro-scanning mode.The malposition of adjacent layers arranged in a hexagonal pattern is at sub-pixel scale.Therefore,sub-pixel processing can be applied to improve the spatial resolution.The images coupled by the adjacent layer fibers are separated,and subsequently,the intermediate image is obtained by histogram matching based on one of the separated image called base image.Finally,the intermediate and base images are processed in the frequency domain.The malposition of the adjacent layer fiber is converted to the phase difference in Fourier transform.Considering the limited sensitivity of the experimental instruments and human sight,the image is set as a band-limited signal and the interpolation function of image fusion is found.The results indicate that a super-resolution image with ultra-high spatial resolution is obtained.     

Charge ordering modulations in a Bi0.4Ca0.6MnO3 film with a thickness of 110 nm

The low temperature sample stage in a transmission electron microscope is used to investigate the charge ordering behaviours in a Bi0.4Ca0.6MnO3 film with a thickness of 110 nm at 103 K. Six different types of superlattice structures are observed using the selected-area electron diffraction （SAED） technique, while three of them match well with the modulation stripes in high-resolution transmission electron microscopy （HRTEM） images. It is found that the modulation periodicity and direction are completely different in the region close to the Bi0.4Ca0.6MnO3/SrTiO3 interface from those in the region a little further from the Bi0.4Ca0.6MnO3/SrTiO3 interface, and the possible reasons for this are discussed. Based on the experimental results, structural models are proposed for these localized modulated structures.