A false color image fusion method based on multi-resolution color transfer in normalization YCBCR space

In this paper, a false color image fusion method for merging visible and infrared images is proposed. Firstly, the source images and reference image are decomposed respectively by Laplacian pyramid transform. Then the grayscale fused image and the difference images between the normalized source images are assigned to construct YC_BC_R components. In the color transfer step, all the three channels of the color space in each decomposition level are processed with the statistic color mapping according to the color characteristics of the corresponding sub-images of the reference image. Color transfer is designed based on the multi-resolution scheme in order to significantly improve the detailed information of the final image, and to reduce excessive saturation phenomenon to have a comparatively natural color appearance compared with the classical global-coloring algorithm. Moreover, the differencing operation between the normalized source images not only provides inter-sensor contrast to make popping the potential targets but also weakens the influence of the ambient illumination variety to a certain degree. Finally, the fused results and several metrics for evaluation of fused images subjectively and objectively illustrate that the proposed color image fusion algorithm can yield a more complete mental representation of the perceived scene, resulting in better situational awareness.     

Effect of UV lamp irradiation during oxidation of Zr/Pt/Si structure on electrical properties of Pt/ZrO2/Pt/Si structure

Metal-insulator-metal (MIM) capacitors were fabricated using ZrO₂ films and the effects of structural and native defects of the ZrO₂ films on the electrical and dielectric properties were investigated. For preparing ZrO₂ films, Zr films were deposited on Pt/Si substrates by ion beam deposition (IBD) system with/without substrate bias voltages and oxidized at 200 °C for 60 min under 0.1 MPa O₂ atmosphere with/without UV light irradiation (λ = 193 nm, Deep UV lamp). The ZrO₂(∼12 nm) films on Pt(∼100 nm)/Si were characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM), capacitance-voltage (C-V) and current-voltage (I-V) measurements were carried out on MIM structures. ZrO₂ films, fabricated by oxidizing the Zr film deposited with substrate bias voltage under UV light irradiation, show the highest capacitance (784 pF) and the lowest leakage current density. The active oxygen species formed by UV irradiation are considered to play an important role in the reduction of the leakage current density, because they can reduce the density of oxygen vacancies.     

Influence of tensile damage on V–I curve and critical current of DyBCO coated conductor

The coated conductors are subjected to mechanical and electromagnetic stresses in preparation and service. When the stress is high, the coated layer is damaged, resulting in loss of superconducting property. The present work was carried out to reveal the influence of tensile damage on V–I curve, critical current and n-value of DyBa₂Cu₃O_7−δ coated conductor. The changes of the V–I curve, critical current and n-value with increasing applied tensile strain were measured experimentally. The features of the shift of the V–I curve to the lower current range and increase in its curvature, and accordingly the decrease in critical current and n-value, with increasing applied strain, were detected. For analysis of the experimental results, the model of Fang et al, which treats with the voltage generation due to the current shunting under existent crack, was applied. The experimentally observed features were described satisfactorily.     

Wood species identification using feature-level fusion scheme

In this paper, we propose a robust wood species identification scheme by using a feature-level fusion scheme. First, a novel wood feature acquirement system is devised, which can get the curve of 1D wood spectral reflectance ratio and the 2D wood surface color image. Second, the 4 wood color features, the 4 principal texture features, the 4 secondary texture features and the 4 spectral features are established, respectively. Third, a fuzzy BP neural network is proposed to perform the classification work, which consists of 4 sub-networks based on the color feature, texture feature and spectral feature. We have experimentally proved that this scheme improves the mean recognition accuracy to approximately 90% for 5 wood species. Moreover, our feature-level fusion scheme is superior to the recognition schemes which use color feature and texture feature.     

Fabrication and characterization of Fe-doped titania semiconductor electrodes with p-n homojunction devices

The nano-TiO₂ electrode with a p-n homojunction device was designed and fabricated by coating of the Fe³⁺-doped TiO₂ (p-type) film on top of the nano-TiO₂ (n-type) film. These films were prepared from synthesized sol-gel TiO₂ samples which were verified as anatase with nano-size particles. The semiconductor characteristics of the p-type and n-type films were demonstrated by current-voltage (I-V) measurements. Results show that the rectifying curves of undoped TiO₂ and Fe³⁺-doped TiO₂ sample films were observed from the I-V data illustration for both the n-type and p-type films. In addition, the shapes of the rectifying curves were influenced by the fabrication conditions of the sample films, such as the doping concentration of the metal ions, and thermal treatments. Moreover, the p-n homojunction films heating at different temperatures were produced and analyzed by the I-V measurements. From the I-V data analysis, the rectifying current of this p-n junction diode has a 10 mA order higher than the current of the n-type film. The p-n homojunction TiO₂ electrode demonstrated greater performance of electronic properties than the n-type TiO₂ electrode.     

Luminescent properties of nanoparticles YPXV1−XO4:Dy phosphors

Phosphors of nanoparticles YP_XV_1−XO₄:Dy³⁺ (0?X?1) have been prepared by a citrate sol-gel method. X-ray diffraction, transmission electron microscope (TEM), scanning electron microscope (SEM) and photoluminescence excitation and emission spectra were utilized to characterize the phosphors. The results of XRD showed that a solid solution formed in YP_XV_1−XO₄:Dy³⁺ phosphor series from X=0 to X=1 with zircon structure. TEM and SEM studies revealed that the obtained YP_XV_1−XO₄:Dy³⁺ nanocrystals appeared to be spherical with some agglomeration and their sizes ranged from 30 to 80 nm. Upon short ultraviolet excitation, the optical properties of all the powder presented that the characteristic transitions of Dy³⁺ due to ⁴F_9/2-⁶H_15/2 (blue) and ⁴F_9/2-⁶H_13/2 (yellow) were detected. Besides this, in the system of YP_XV_1−XO₄:Dy³⁺, the yellow-to-blue intensity ratio (Y/B) depended on the value of P/V greatly, with the increasing of X value and the decreased Y/B value. The phosphor found to yield white light when the value of X in the range of X=0.775-0.85, the optimum concentration for Dy³⁺ is 1 mol% of Y in the host, and the emission intensity increased with the annealing temperature.     

The I-V characteristics of InAs/GaAs quantum dot laser

The I-V characteristics of an InAs/GaAs quantum dot (QD) laser diode have been investigated under both the high and low input current conditions. Under the low current condition, the I-V curve obeys the Shockley equation, from which the forbidden energy gap of the junction can be derived. On the other hand, in the high current range, the I-V characteristics violate the Shockley equation and the device tends to operate as a resistance. In addition, the I-V curve can be used to fit the temperature coefficient of the forward voltage, which is a critical parameter for determining the junction temperature of the laser diode.     

Al Kα and Cu Kα1 excited XPS of vanadium oxide and VF3 powders: Measurement of the V 1s – KLL Auger parameters

Al Kα (hν = 1486.6 eV) excited XPS shows that powder samples of V₂O₃, V₂O₅ and VF₃ are surface contaminated and that the V₂O₃ can be cleaned by heating in vacuum at 400 °C. The greater sampling depth of Cu Kα₁ (hν = 8047.8 eV) excited XPS allows measurement of the bulk V 1s – KL₂L₃ Auger parameters (APs) for these materials. The APs of VF₃ and V₂O₅, relative to V metal, fall into the range of values expected for metal fluorides and oxides with non-local final state core-hole screening, whereas the AP of V₂O₃ is significantly closer to that of V metal. We ascribe this to a greater final state valence orbital occupation following photionisation in V₂O₃, part of which results from metal-like screening.     

Quantitative T(1)(ρ) imaging using phase cycling for B0 and B1 field inhomogeneity compensation

T_1ρ imaging is useful in a number of clinical applications. T_1ρ preparation methods, however, are sensitive to non-uniformities of the B₀ magnetic field and the B₁ RF field. These common system imperfections can result in image artifacts and quantification errors in T_1ρ imaging. We report on a phase-cycling method which can eliminate B₁ RF inhomogeneity effects in T_1ρ imaging. This method does not only correct for image artifacts but also for T_2ρ contamination caused by B₁ RF inhomogeneity. The presence of B₀ magnetic field inhomogeneity can compromise the effectiveness of this method for B₁ RF inhomogeneity correction. We demonstrate that, by combining the spin-locking scheme reported by Dixon et al. (Myocardial suppression in vivo by spin locking with composite pulses. Magn Reson Med 1996; 36:90-94) with phase cycling, we can simultaneously correct B₀ magnetic field inhomogeneity effects and B₁ RF inhomogeneity effects in T_1ρ imaging. Phantom and in vivo data sets are used to demonstrate the proposed methods and to compare them with other existing T_1ρ preparation methods.     

The effect of PVA (Bi2O3-doped) interfacial layer and series resistance on electrical characteristics of Au/n-Si (110) Schottky barrier diodes (SBDs)

Two types of Schottky Barrier Diodes (SBDs) with and without PVA (Bi₂O₃-doped) polymeric interfacial layer, were fabricated and measured at room temperature in order to investigate the effects of the PVA (Bi₂O₃-doped) interfacial layer on the main electrical parameters such as the ideality factor (n), zero-bias barrier height (Φ_B0), series resistance (R_s) and interface-state density (N_ss). Electrical parameters of these two diodes were calculated from the current-voltage (I-V) characteristics and compared with each other. The values of Φ_B0, n and R_s for SBDs without polymeric interfacial layer are 0.71 eV, 1.44 and 4775 Ω, respectively. The values of Φ_B0, n and R_s for SBDs with PVA (Bi₂O₃-doped) polymeric interfacial layer are 0.74 eV, 3.49 and 10,030 Ω, respectively. For two SBDs, the energy density distribution profiles of interface states (N_ss) were obtained from forward-bias I-V measurements by taking the bias dependence of R_s of these devices into account. The values of N_ss obtained for the SBD with PVA (Bi₂O₃-doped) polymeric interfacial layer are smaller than those of the SBD without polymeric interfacial layer.     

Structures and magnetic anisotropy of β-Mn2V2O7 crystals synthesized by the molten salt method

β-Mn2V2O7 crystals with strip shape are successfully prepared by the molten salt method in a closed crucible,and are characterized by x-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),selected area of electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM).The results indicate that the sample is of the β-Mn2V2O7 crystal with monoclinic symmetry,level natural cleavage facets and directional growth.Magnetic properties are measured by vibration sample magnetometry (VSM) at room temperature,and the magnetic hysteresis loop indicates that the β-Mn2V2O7 has anti-ferromagnetic properties with low coercive force and remnant magnetization.The magnetic measurement results in different directions exhibit that the β-Mn2V2O7 has magnetic anisotropy,which is due to the fact that the magnetic interaction energy of the β-Mn2V2O7 is lowest only when the electron configuration is in a certain direction.     

Effects of V2O5 addition on NiZn ferrite synthesized using two-step sintering process

The combined influence of a two-step sintering (TSS) process and addition of V₂O₅ on the microstructure and magnetic properties of NiZn ferrite was investigated. As comparison, samples prepared by the conventional single-step sintering (SSS) procedure were also studied. It was found that with 0.3 wt% V₂O₅ additive, the sample sintered by the two-step sintering process at a high temperature of 1250 °C for 30 min and a lower temperature of 1180 °C for 3 h exhibited more homogeneous microstructure and higher permeability with a high Q-factor. The results showed that the TSS method with suitable additive brought positive improvement of the microstructure and magnetic properties of NiZn ferrite.     

Hydrogen permeation of Pd-coated V90Al10 alloy membranes at different pressures in the presence and absence of carbon dioxide

The hydrogen permeation characteristics of alloy membranes based on Pd-coated V₉₀Al₁₀ alloy membrane have been investigated in the pressure range 1-3 atm under pure hydrogen and hydrogen-carbon dioxide gas mixture at 450 °C. Hydrogen permeation experiments have been confirmed that hydrogen flux was 21.1 ml/min/cm² for a Pd-coated V₉₀Al₁₀ alloy membrane (thickness: 0.5 mm) using pure hydrogen as the feed gas. It has been found that Pd-coated V₉₀Al₁₀ alloy membranes exhibit good resistance to hydrogen embrittlement in pure hydrogen atmosphere. After different hydrogen permeation flux tests under different pressure condition in presence of hydrogen-carbon dioxide gas mixture, the characteristics of the Pd-coated V₉₀Al₁₀ alloy membranes were examined by ex-situ analysis techniques. The loss of cell performance observed in the presence of hydrogen-carbon dioxide gas mixture is mainly attributed to both physical and chemical degradations of membrane, which led to structural changes in the Pd-coated V₉₀Al₁₀ alloy membrane.     

Variable order spherical harmonic expansion scheme for the radiative transport equation using finite elements

We propose the P_N approximation based on a finite element framework for solving the radiative transport equation with optical tomography as the primary application area. The key idea is to employ a variable order spherical harmonic expansion for angular discretization based on the proximity to the source and the local scattering coefficient. The proposed scheme is shown to be computationally efficient compared to employing homogeneously high orders of expansion everywhere in the domain. In addition the numerical method is shown to accurately describe the void regions encountered in the forward modeling of real-life specimens such as infant brains. The accuracy of the method is demonstrated over three model problems where the P_N approximation is compared against Monte Carlo simulations and other state-of-the-art methods.     

Substrate effects on V2O3 thin films

We apply density functional theory and the augmented spherical wave method to analyze the electronic structure of V₂O₃ in the vicinity of an interface to Al₂O₃. The interface is modeled by a heterostructure setup of alternating vanadate and aluminate slabs. We focus on the possible modifications of the V₂O₃ electronic states in this geometry, induced by the presence of the aluminate layers. In particular, we find that the tendency of the V 3d states to localize is enhanced and may even cause a metal-insulator transition.     

Feasibility of using limited-population-based average R10 for pharmacokinetic modeling of osteosarcoma dynamic contrast-enhanced magnetic resonance imaging data

Retrospective analyses of clinical dynamic contrast-enhanced (DCE) MRI studies may be limited by failure to measure the longitudinal relaxation rate constant (R₁) initially, which is necessary for quantitative analysis. In addition, errors in R₁ estimation in each individual experiment can cause inconsistent results in derivations of pharmacokinetic parameters, K^trans and v_e, by kinetic modeling of the DCE-MRI time course data. A total of 18 patients with lower extremity osteosarcomas underwent multislice DCE-MRI prior to surgery. For the individual R₁ measurement approach, the R₁ time course was obtained using the two-point R₁ determination method. For the average R₁₀ (precontrast R₁) approach, the R₁ time course was derived using the DCE-MRI pulse sequence signal intensity equation and the average R₁₀ value of this population. The whole tumor and histogram median K^trans (0.57±0.37 and 0.45±0.32 min⁻¹) and v_e (0.59±0.20 and 0.56±0.17) obtained with the individual R₁ measurement approach are not significantly different (paired t test) from those (K^trans: 0.61±0.46 and 0.44±0.33 min⁻¹; v_e: 0.61±0.19 and 0.55±0.14) obtained with the average R₁₀ approach. The results suggest that it is feasible, as well as practical, to use a limited-population-based average R₁₀ for pharmacokinetic modeling of osteosarcoma DCE-MRI data.     

Investigation of diode parameters using I-V and C-V characteristics of In/SiO2/p-Si (MIS) Schottky diodes

A study on interface states density distribution and characteristic parameters of the In/SiO₂/p-Si (MIS) capacitor has been made. The thickness of the SiO₂ film obtained from the measurement of the corrected capacitance in the strong accumulation region for MIS Schottky diodes was 220 Å. The diode parameters from the forward bias I-V characteristics such as ideality factor, series resistance and barrier heights were found to be 1.75, 106-112 Ω and 0.592 eV, respectively. The energy distribution of the interface state density D_it was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. The interface state density obtained using the I-V characteristics had an exponential growth, with bias towards the top of the valance band, from 9.44×10¹³ eV⁻¹ cm⁻² in 0.329-E_v eV to 1.11×10¹³ eV⁻¹ cm⁻² in 0.527-E_v eV at room temperature. Furthermore, the values of interface state density D_it obtained by the Hill-Coleman method from the C-V characteristics range from 52.9×10¹³ to 1.11×10¹³ eV⁻¹ cm⁻² at a frequency range of 30kHz-1 MHz. These values of D_it and R_s were responsible for the non-ideal behaviour of I-V and C-V characteristics.     

Modulation structure in the STM images of the non-metallic misfit-layer compound (PbS)1.12VS2

This paper presents the scanning tunneling microscopy (STM) results of the misfit-layer compound (PbS)_1.12VS₂, which is constructed of alternately stacking of PbS (Q) and VS₂ (H) layers. Temperature dependent resistivity measurements show a semiconducting behavior with small activation energies. Unlike the metallic 1Q/1H type of compounds we have succeeded to take both the STM images of a Q layer and a H layer, because electron tunneling from the underlying H layer is suppressed when intermediate positive bias voltage (V_b) is applied to a tip. At V_b = 0.15 V the image shows pseudo-tetragonal arrays of bright spots, although it is obscure with decreasing bias voltage and disappears at less than 10 mV. A modulation structure is found on the H layer of a stepped surface on which surface atoms are undulated in a period being twice the V-V interatomic distance in the [1 0]_H or the [1 1]_H direction.