Rapid identifying high-influence nodes in complex networks
Singular and non-topological soliton solutions for nonlinear fractional differential equations
In this article, the fractional derivatives are described in the modified Riemann-Liouville sense. We propose a new approach, namely an ansatz method, for solving fractional differential equations (FDEs) based on a fractional complex transform and apply it to solve nonlinear space-time fractional equations. As a result, the non-topological as well as the singular soliton solutions are obtained. This method can be suitable and more powerful for solving other kinds of nonlinear fractional FDEs arising in mathematical physics.
Analysis of elastoplasticity problems using an improved complex variable element-free Galerkin method
In this paper, based on the conjugate of the complex basis function, a new complex variable moving least-squares approximation is discussed. Then using the new approximation to obtain the shape function, an improved complex variable element-free Galerkin (ICVEFG) method is presented for two-dimensional (2D) elastoplasticity problems. Compared with the previous complex variable moving least-squares approximation, the new approximation has greater computational precision and efficiency. Using the penalty method to apply the essential boundary conditions, and using the constrained Galerkin weak form of 2D elastoplasticity to obtain the system equations, we obtain the corresponding formulae of the ICVEFG method for 2D elastoplasticity. Three selected numerical examples are presented using the ICVEFG method to show that the ICVEFG method has the advantages such as greater precision and computational efficiency over the conventional meshless methods.
Conservative method for simulation of a high-order nonlinear Schrödinger equation with a trapped term
Transformation optics for efficient calculation of transmembrane voltage induced on cells
We present a novel efficient approach in calculating induced transmembrane voltage (ITV) on cells based on transformation optics. As cell membrane is much thinner than the dimension of a typical cell, discretizing the membrane needs numerous meshes. Using an anisotropic medium based on transformation optics, the thickness of the membrane can be exaggerated by at least one order, which eliminates rigorous mesh refinement and reduces unknowns greatly. The accuracy and efficiency of the proposed method are verified by a cylindrical cell model. Moreover, the influence on ITV with bound water (BW) layers is also studied. The results show that when cells are exposed to nanosecond electric field, BW layers should be rigorously considered in calculating ITV.
Time-domain nature of group delay
A new kind of special function and its application
Shannon information entropies for position-dependent mass Schrödinger problem with a hyperbolic well
Characterizing the dynamics of quantum discord under phase damping with POVM measurements
Non-Markovianity of a qubit coupled with an isotropic Lipkin-Meshkov-Glick bath
Scheme for purifying a general mixed entangled state and its linear optical implementation
We propose a scheme for purification of a general mixed entangled state. In this scheme, we start from a large number of general mixed entangled states and end up, after local operation and classical communication, with a smaller number of Bell diagonal states with higher entanglement. In particular, the scheme can purify one maximally entangled state from two entangled pairs prepared in a class of mixed entangled state. Furthermore we propose a linear optical implementation of the present scheme with polarization beam splitters and photon detectors.
Deterministic joint remote state preparation of arbitrary single- and two-qubit states
A perturbation method to the tent map based on Lyapunov exponent and its application
Perturbation imposed on a chaos system is an effective way to maintain its chaotic features. A novel parameter perturbation method for the tent map based on the Lyapunov exponent is proposed in this paper. The pseudo-random sequence generated by the tent map is sent to another chaos function – the Chebyshev map for the post processing. If the output value of the Chebyshev map falls into a certain range, it will be sent back to replace the parameter of the tent map. As a result, the parameter of the tent map keeps changing dynamically. The statistical analysis and experimental results prove that the disturbed tent map has a highly random distribution and achieves good cryptographic properties of a pseudo-random sequence. As a result, it weakens the phenomenon of strong correlation caused by the finite precision and effectively compensates for the digital chaos system dynamics degradation.
A novel adaptive-impulsive synchronization of fractional-order chaotic systems
Synchronization of coupled chaotic Hindmarsh Rose neurons: An adaptive approach
In this paper, we consider the synchronization of chaotic Hindmarsh Rose (HR) neurons via a scalar control input. Chaotic HR neurons coupled with a gap junction are taken into consideration, and an active compensation mechanism-based adaptive control is employed to realize the synchronization of two HR neurons. As such an adaptive control is utilized, an accurate model of the system is of no necessity. Asymptotical synchronization of two HR neurons is guaranteed by theoretical results. Numerical results are also provided to confirm the proposed synchronization approach.
Dynamics and stabilization of peak current-mode controlled buck converter with constant current load
The ac Stark shifts of the terahertz clock transitions of barium
Wavelength-dependent AC Stark shifts and magic wavelengths of the terahertz clock transitions between the metastable triplet states 6s5d 3D1 and 6s5d 3D2 are investigated with considering the optical lattice trapping of barium atoms with the linearly polarized laser. The trap depths and the slopes of light shift difference with distinct magic wavelengths of the optical lattices are also discussed in detail. Several potentially suitable working points for the optical lattice trapping laser are recommended and selected from these magic wavelengths.
Extreme ultraviolet and x-ray transition wavelengths in Rb XXIV
Role of elastic scattering in high-order above threshold ionization
The VMI study on angular distribution of ejected electrons from Eu 4f76p1/26dautoionizing states
Resonant charge transfer in slow Li+-Li(2s) collisions
The resonant charge transfer process for Li+-Li(2s) collision is investigated by the quantum-mechanical molecular orbital close-coupling (QMOCC) method and the two-center atomic-orbital close-coupling (AOCC) method in an energy range of 1.0 eV/u-104 eV/u. Accurate molecular structure data and charge transfer cross sections are given. Both the all-electron model (AEM) and one-electron model (OEM) are used in the QMOCC calculations, and the discrepancies between the two models are analyzed. The OEM calculation can also give a reliable prediction of the cross sections for energies below 1 keV/u.
Site preferences and lattice vibrations of Nd6Fe13-xTxSi(T = Co, Ni)
Single ionization of helium atoms by energetic fully stripped carbon ions
A four-body distorted wave approximation is presented for theoretical investigations of the single ionization of ground-state helium atoms by fully stripped carbon ions at impact energies of 2 MeV/amu and 100 MeV/amu. The nine-dimensional integrals for the partial quantum-mechanical transition amplitudes of the specified reaction are reduced to some analytical expressions or one-dimensional integrals over real variables. Fully differential cross sections (FDCSs) are calculated and compared with their experimental values as well as the results obtained from other theories. Despite the simplicity and quickness of the proposed quadrature, the comparison shows that the obtained results are in reasonable agreement with the experiment and are compatible with those of other complicated theories.
Modeling the interaction of nitrate anions with ozone and atmospheric moisture
The molecular dynamics method is used to investigate the interaction between one-six nitrate anions and water clusters absorbing six ozone molecules. The infrared (IR) absorption and reflection spectra are reshaped significantly, and new peaks appear at Raman spectra due to the addition of ozone and nitrate anions to the disperse water system. After ozone and nitrate anions are captured, the average (in frequency) IR reflection coefficient of the water disperse system increased drastically and the absorption coefficient fell.
Reciprocity principle-based model for shielding effectiveness prediction of a rectangular cavity with a covered aperture
Design and development of high linearity millimeter wave traveling-wave tube for satellite communications
Exploring electromagnetic response of tellurium dielectric resonator metamaterial at the infrared wavelengths
Tunable wideband absorber based on resistively loaded lossy high-impedance surface
Absorption enhancement in thin film a-Si solar cells with double-sided SiO2 particle layers
Superscattering-enhanced narrow band forward scattering antenna
Ghost imaging with broad distance
An iterative virtual projection method to improve the reconstruction performance for ill-posed emission tomographic problems
Field-free orientation of diatomic molecule via the linearly polarized resonant pulses
Photon pair source viatwo coupling single quantum emitters
We study the two coupling two-level single molecules driven by an external field as a photon pair source. The probability of emitting two photons, P2, is employed to describe the photon pair source quality in a short time, and the correlation coefficient RAB is employed to describe the photon pair source quality in a long time limit. The results demonstrate that the coupling single quantum emitters can be considered as a stable photon pair source.
Movement of a millimeter-sized oil drop pushed by optical force
Entanglements in a coupled cavity-array with one oscillating end-mirror
Plasmonic emission and plasma lattice structures induced by pulsed laser in Purcell cavity on silicon
Analysis of gain distribution in cladding-pumped thulium-doped fiber laser and optical feedback inhibition problem in fiber-bulk laser system
The steady-state gain distribution in cladding pumped thulium-doped fiber laser (TDFL) is analytically and numerically solved based on the rate equations including loss coefficients and cross relaxation effect. With the gain curve, a problem, which is named optical feedback inhibition (OFI) and always occurs in tandem TDFL-Ho:YAG laser system, is analyzed quantitatively. The actual characteristics of output spectra and power basically prove the conclusion of theoretical analysis. Then a simple mirror-deflected L-shaped cavity is employed to restrain the external feedback and simplify the structure of fiber-bulk Ho:YAG laser. Finally, 25 W of 2097-nm laser power and 51.2% of optical-to-optical conversion efficiency are obtained, and the beam quality factor is less than 1.43 obtained by knife-edge method.
Arbitrary frequency stabilization of a diode laser based on visual Labview PID VI and sound card output
Broadband and high-speed swept external-cavity laser using a quantum-dot superluminescent diode as gain device
A wide wavelength tuning range swept external-cavity laser using an InAs/GaAs quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Littrow telescope-less configuration. The swept laser generates greater than 54-mW peak output power and up to 33-kHz sweep rate with a sweep range of 150 nm centered at 1155 nm. The effects of injection current and sweep rate on the sweep performance of the swept laser are studied.
An optical fiber spool for laser stabilization with reduced acceleration sensitivity to 10-12/g
V-L decomposition of a novel full-waveform lidar system based on virtual instrument technique
Confinement-induced nanocrystal alignment of conjugated polymer by the soft-stamped nanoimprint lithography
Soft-stamped nanoimprint lithography (NIL) is considered as one of the most effective processes of nanoscale patterning because of its low cost and high throughput. In this work, this method is used to emboss the poly (9, 9-dioctylfluorene) film. By reducing the linewidth of the nanogratings on the stamp, the orientations of nanocrystals are confined along the grating vector in the nanoimprint process, where the confinement linewidth is comparable to the geometrical size of the nanocrystal. When the linewidth is about 400 nm, the poly (9, 9-dioctylfluorene) (PFO) nanocrystals could be orderly arranged in the nanogratings, so that both pattern transfer and well-aligned nanocrystal arrangement could be achieved in a single step by the soft-stamped NIL. The relevant mechanism of the nanocrystalline alignment in these nanogratings is fully discussed. The modulation of nanocrystal alignment is of benefit to the charge mobilities and other performances of PFO-based devices for the future applications.
Analysis of the spatial filter of a dielectric multilayer film reflective cutoff filter-combination device
Quantitative calculation of reaction performance in sonochemical reactor by bubble dynamics
Wavefront modulation of water surface wave by a metasurface
Temperature imaging with speed of ultrasonic transmission tomography for medical treatment control: A physical model-based method
Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic
Skew-gradient representation of generalized Birkhoffian system
The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of the skew-gradient system are used to study the properties, especially the stability, of the generalized Birkhoffian system. Some examples are given to illustrate the application of the result.
Effects of the computational domain on the secondary flow in turbulent plane Couette flow
Ferrofluid nucleus phase transitions in an external uniform magnetic field
Dynamic mechanical analysis of single walled carbon nanotubes/polymethyl methacrylate nanocomposite films
Effect of microwave frequency on plasma formation in air breakdown at atmospheric pressure
Investigation of high sensitivity radio-frequency readout circuit based on AlGaN/GaN high electron mobility transistor
Complementary method to locate atomic coordinates by combined searching method of structure-sensitive indexes based on bond valence method
Influences of surface and flexoelectric polarization on the effective anchoring energy in nematic liquid crystal
Determination of electrostatic parameters of a coumarin derivative compound C17H13NO3 by x-ray and density functional theory
New crystal structure and physical properties of TcB from first-principles calculations
Influences of neutral oxygen vacancies and E1'centers on α-quartz
Our calculations demonstrate that the concentration of neutral oxygen vacancies can affect the geometrical structrue, electronic structure, and optical properties of α -quartz. Moreover, the distribution of the neutral oxygen divacancy can also exert some influence on the properties of α -quartz. The dissimilarity and similarities are presented in the corresponding density of state (DOS) and absorption spectrum. In addition, when a higher defect concentration is involved in α -quartz, the influence of E1' center on the geometry of α -quartz becomes more significant. However, the introduction of an E1' center barely results in any improvement compared with the influence produced by the corresponding neutral defect.
Analysis of functional failure mode of commercial deep sub-micron SRAM induced by total dose irradiation
Analysis of recoverable and permanent components of threshold voltage shift in NBT stressed p-channel power VDMOSFET
Mechanical strains in pecvd SiNx:H films for nanophotonic application
Hydrogenated amorphous silicon nitride films (SiNx:H) are deposited at low temperature by high-frequency plasma-enhanced chemical vapor deposition (HF PECVD). The main effort is to investigate the roles of plasma frequency and plasma power density in determining the film properties particularly in stress. Information about chemical bonds in the films is obtained by Fourier transform infrared spectroscopy (FTIR). The stresses in the SiNx:H film are determined from substrate curvature measurements. It is shown that plasma frequency plays an important role in controlling the stresses in SiNx:H films. For silicon nitride layers grown at plasma frequency 40.68 MHz initial tensile stresses are observed to be in a range of 400 MPa-700 MPa. Measurements of the intrinsic stresses of silicon nitride films show that the stress quantity is sufficient for film applications in strained silicon photonics.
Structural, elastic, and electronic properties of sodium atoms encapsulated type-I silicon-clathrate compound under high pressure
Nano LaAlO3 buffer layer-assisted tunneling current in manganite p-n heterojunction
Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis
High response Schottky ultraviolet photodetector formed by PEDOT:PSS transparent electrode contacts to Mg0.1Zn0.9O
Effect of the annealing temperature on the long-term thermal stability of Pt/Si/Ta/Ti/4H-SiC contacts
Rectification and electroluminescence of nanostructured GaN/Si heterojunction based on silicon nanoporous pillar array
A C-band 55% PAE high gain two-stage power amplifier based on AlGaN/GaN HEMT
A C-band high efficiency and high gain two-stage power amplifier based on AlGaN/GaN high electron mobility transistor (HEMT) is designed and measured in this paper. The input and output impedances for the optimum power-added efficiency (PAE) are determined at the fundamental and 2nd harmonic frequency (f0 and 2f0). The harmonic manipulation networks are designed both in the driver stage and the power stage which manipulate the second harmonic to a very low level within the operating frequency band. Then the inter-stage matching network and the output power combining network are calculated to achieve a low insertion loss. So the PAE and the power gain is greatly improved. In an operation frequency range of 5.4 GHz-5.8 GHz in CW mode, the amplifier delivers a maximum output power of 18.62 W, with a PAE of 55.15% and an associated power gain of 28.7 dB, which is an outstanding performance.
Fermi level pinning effects at gate-dielectric interfaces influenced by interface state densities
Lateral resistance reduction induced by light-controlled leak current in silicon-based Schottky junction
Lateral resistance of silicon-based p-type and n-type Schottky junctions is investigated. After one electrode on a metallic film is irradiated, the differential lateral resistance of the system is dependent on the direction of the bias current: it keeps constant in one direction and decreases in the opposite direction. By systematically investigating the electrical potential changes in silicon and the junction, we propose a new mechanism based on light-controlled leak current. Our work provides an insight into the nature of this phenomenon and will facilitate the advanced design of switchable devices.
Magnetic hysteresis, compensation behaviors, and phase diagrams of bilayer honeycomb lattices
Exact solution of Heisenberg model with site-dependent exchange couplings and Dzyloshinsky-Moriya interaction
We propose an integrable spin-1/2Heisenberg model where the exchange couplings and Dzyloshinky-Moriya interactions are dependent on the sites. By employing the quantum inverse scattering method, we obtain the eigenvalues and the Bethe ansatz equation of the system with the periodic boundary condition. Furthermore, we obtain the exact solution and study the boundary effect of the system with the anti-periodic boundary condition via the off-diagonal Bethe ansatz. The operator identities of the transfer matrix at the inhomogeneous points are proved at the operator level. We construct the T-Q relation based on them. From which, we obtain the energy spectrum of the system. The corresponding eigenstates are also constructed. We find an interesting coherence state that is induced by the topological boundary.
Effects of oxidation of DyH3 in Nd-Fe-B sintered magnets
Effects of R-site compositions on the meta-magnetic behavior of Tb1-xPrx(Fe0.4Co0.6)1.88C0.05 (x= 0, 0.8, and 1)
We investigate the low-temperature magnetic properties of intermetallic compounds Tb1-xPrx(Fe0.4Co0.6)1.88C0.05 (x= 0, 0.8, and 1) by detailed magnetization measurements. Obvious temperature- and field-induced irreversibilities suggest the coexistence of multiple magnetic phases. Sharp magnetization jumps across the antiferromagnetic to ferromagnetic transition are observed only in the Pr-containing samples, indicating that the behavior of the avalanche-like growth of ferromagnetic clusters is mainly related to the light lanthanide Pr ions. In addition, the time relaxation, field sweep rate, and cooling field dependence of magnetization jumps in the sample with x= 1 are consistent with those in the martensitic scenario.
Magnetic–optical bifunctional CoPt±b3/Co multilayered nanowire arrays
Lumped-equivalent circuit model for multi-stage cascaded magnetoelectric dual-tunable bandpass filter
The interface density dependence of the electrical properties of 0.9Pb(Sc0.5Ta0.5)O3-0.1PbTiO3/0.55Pb(Sc0.5Ta0.5)O3-0.45PbTiO3 multilayer thin films
Nanoscale domain switching mechanism of Bi3.15Eu0.85Ti3O12 thin film under the different mechanical forces
Effects of surface adsorbed oxygen, applied voltage, and temperature on UV photoresponse of ZnO nanorods
The ultraviolet (UV) photoresponses of ZnO nanorods directly grown on and between two micro Au-electrodes by using electric-field-assisted wet chemical method are measured comprehensively under different conditions, including ambient environment, applied bias voltage, gate voltage and temperature. Experimental results indicate that the photoresponses of the ZnO nanorods can be modulated by surface oxygen adsorptions, applied voltages, as well as temperatures. A model taking into account both surface adsorbed oxygen and electron-hole activities inside ZnO nanorods is proposed. The enhancement effect of the bias voltage on photoresponse is also analyzed. Experimental results shows that the UV response time (to 63%) of ZnO nanorods in air and at 59 ℃ could be shortened from 34.8 s to 0.24 s with a bias of 4 V applied between anode and cathode.
C–H complex defects and their influence in ZnO single crystal
Temperature dependences of ferroelectricity and resistive switching behavior of epitaxial BiFeO3 thin films
Multifunctional disk device for optical switch and temperature sensor
Single-layer dual-band terahertz filter with weak coupling between two neighboring cross slots
A dual-band terahertz (THz) filter consisting of two different cross slots is designed and fabricated in a single molybdenum layer. Experimental verification by THz time-domain spectroscopy indicates good agreement with the simulation results. Owing to the weak coupling between the two neighboring cross slots in the unit cell, good selectivity performance can be easily achieved, both in the lower and higher bands, by tuning the dimensions of the two crosses. The physical mechanisms of the dual-band resonant are clarified by using three differently configured filters and electric field distribution diagrams. Owing to the rotational symmetry of the cross-shaped filter, the radiation at normal incidence is insensitive to polarization. Compared with the THz dual-band filters that were reported earlier, these filters also have the advantages of easy fabrication and low cost, which would find applications in dual-band sensors, THz communication systems, and emerging THz technologies.
Simulation of positron backscattering and implantation profiles using Geant4 code
Exploring positron characteristics utilizing two new positron-electron correlation schemes based on multiple electronic structure calculation methods
We make a gradient correction to a new local density approximation form of positron-electron correlation. The positron lifetimes and affinities are then probed by using these two approximation forms based on three electronic-structure calculation methods, including the full-potential linearized augmented plane wave (FLAPW) plus local orbitals approach, the atomic superposition (ATSUP) approach, and the projector augmented wave (PAW) approach. The differences between calculated lifetimes using the FLAPW and ATSUP methods are clearly interpreted in the view of positron and electron transfers. We further find that a well-implemented PAW method can give near-perfect agreement on both the positron lifetimes and affinities with the FLAPW method, and the competitiveness of the ATSUP method against the FLAPW/PAW method is reduced within the best calculations. By comparing with the experimental data, the new introduced gradient corrected correlation form is proved to be competitive for positron lifetime and affinity calculations.
Temperature-dependent photoluminescence spectra of GaN epitaxial layer grown on Si (111) substrate
In this paper, the temperature-dependent photoluminescence (PL) properties of GaN grown on Si (111) substrate are studied. The main emission peaks of GaN films grown on Si (111) are investigated and compared with those grown on sapphire substrates. The positions of free and bound exciton luminescence peaks, i.e., FXA and D0X peaks, of GaN films grown on Si (111) substrates undergo red shifts compared with those grown on sapphire. This is attributed to the fact that the GaN films grown on sapphire are under the action of compressive stress, while those grown on Si (111) substrate are subjected to tensile stress. Furthermore, the positions of these peaks may be additionally shifted due to different stress conditions in the real sample growth. The emission peaks due to stacking faults are found in GaN films grown on Si (111) and an S-shaped temperature dependence of PL spectra can be observed, owing to the influence of the quantum well (QW) emission by the localized states near the conduction band gap edge and the temperature-dependent distribution of the photo-generated carriers.
Influences of hydrogen dilution on microstructure and optical absorption characteristics of nc-SiOx:H film
Ion and water transport in charge-modified graphene nanopores
Surface morphology and electrochemical characterization of electrodeposited Ni–Mo nanocomposites as cathodes for hydrogen evolution
Closed-form solution of mid-potential between two parallel charged plates with more extensive application
Efficient calculation of the electrostatic interactions including repulsive force between charged molecules in a biomolecule system or charged particles in a colloidal system is necessary for the molecular scale or particle scale mechanical analyses of these systems. The electrostatic repulsive force depends on the mid-plane potential between two charged particles. Previous analytical solutions of the mid-plane potential, including those based on simplified assumptions and modern mathematic methods, are reviewed. It is shown that none of these solutions applies to wide ranges of inter-particle distance from 0 to 10 and surface potential from 1 to 10. Three previous analytical solutions are chosen to develop a semi-analytical solution which is proven to have more extensive applications. Furthermore, an empirical closed-form expression of mid-plane potential is proposed based on plenty of numerical solutions. This empirical solution has extensive applications, as well as high computational efficiency.
Dual-band LTCC antenna based on 0.95Zn2SiO4-0.05CaTiO3 ceramics for GPS/UMTS applications
Charge and spin-dependent thermal efficiency of polythiophene molecular junction in presence of dephasing
Simulation study of the losses and influences of geminate and bimolecular recombination on the performances of bulk heterojunction organic solar cells
An improved GGNMOS triggered SCR for high holding voltage ESD protection applications
A novel diode string triggered gated-PiN junction device for electrostatic discharge protection in 65-nm CMOS technology
Electrical properties of zinc-oxide-based thin-film transistors using strontium-oxide-doped semiconductors
A threshold voltage model of short-channel fully-depleted recessed-source/drain (Re-S/D) SOI MOSFETs with high-k dielectric
Fabrication and characterization of novel high-speed InGaAs/InP uni-traveling-carrier photodetector for high responsivity
A top-illuminated circular mesa uni-traveling-carrier photodetector (UTC-PD) is proposed in this paper. By employing Gaussian graded doping in InGaAs absorption layer and InP depleted layer, the responsivity and high speed response characteristics of the device are optimized simultaneously. The responsivity up to 1.071 A/W (the external quantum efficiency of 86%) is obtained at 1550 nm with a 40-μ diameter device under 10-V reverse bias condition. Meanwhile, the dark current of 7.874 nA and the 3-dB bandwidth of 11 GHz are obtained with the same device at a reverse bias voltage of 3 V.
Ultrafast structural dynamics studied by kilohertz time-resolved x-ray diffraction
Investigation of noise properties in grating-based x-ray phase tomography with reverse projection method
The relationship between noise variance and spatial resolution in grating-based x-ray phase computed tomography (PCT) imaging is investigated with reverse projection extraction method, and the noise variances of the reconstructed absorption coefficient and refractive index decrement are compared. For the differential phase contrast method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both theoretical analysis and simulations demonstrate that in PCT the noise variance of the reconstructed refractive index decrement scales with spatial resolution follows an inverse linear relationship at fixed slice thickness, while the noise variance of the reconstructed absorption coefficient conforms with the inverse cubic law. The results indicate that, for the same noise variance level, PCT imaging may enable higher spatial resolution than conventional absorption computed tomography (ACT), while ACT benefits more from degraded spatial resolution. This could be a useful guidance in imaging the inner structure of the sample in higher spatial resolution.
Flexible reduced field of view magnetic resonance imaging based on single-shot spatiotemporally encoded technique
In many ultrafast imaging applications, the reduced field-of-view (rFOV) technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporally-encoded (SPEN) method offers an inherent applicability to rFOV imaging. In this study, a flexible rFOV imaging method is presented and the superiority of the SPEN approach in rFOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging (EPI) experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the rFOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest (ROIs) with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging.
Analysis of the interdigitated back contact solar cells: The n-type substrate lifetime and wafer thickness
GaInP/GaAs tandem solar cells with highly Te- and Mg-doped GaAs tunnel junctions grown by MBE
Improved routing strategy based on gravitational field theory
Spatiotemporal distribution characteristics and attribution of extreme regional low temperature event