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In recent years, theories of nanoparticles extensively feature in discussions of diagnostic and treatment of cardio-vascular diseases in the medical field. This paper proposes a mathematical model for the pulsatile flow of Bingham fluid blood with magnetic particles through a diseased artery. It is assumed that the artery has a porous medium and is tapered with mild stenosis. Further, it is subjected to an external body acceleration and an applied electromagnetic field. Instead of considering an approximate interaction force between the suspended particle and the fluid, the actual interaction force between them is considered in the current study. By introducing the term actual drag force in the momentum equation, flow governing equations are derived and solved using integral transform method. The impact of various pertinent parameters such as the yield stress, radius of the particle, particle concentration number, mass number, electric field intensity, magnetic field strength, stenosis geometry, and body acceleration number on the flow characteristics is analyzed through numerical calculations and graphs. The radius of the particle increases the speed of both fluid and particle. Both particle concentration and mass number increase the shear stress at the arterial wall. On the other hand, the electric width number and the permeability number considerably decrease its value. The body acceleration number increases the flow resistance for the fixed pressure gradient, and it is more in the diverging tube than the converging and non-tapering section of the tube. A comparative study of the flow variables with actual drag force and approximate drag force is examined along with the effects of actual interaction force in order to understand its remarkable influence on the magnitude of flow velocity, wall shear stress and flow resistance. [ABSTRACT FROM AUTHOR]

The electrical characteristics of a V/p-GaN Schottky junction have been investigated by current-voltage (I-V) and capacitance-voltage (C-V) characteristics under the assumption of the thermionic emission (TE) theory in the temperature range of 120-280 K with steps of 40 K. The zero-bias barrier height (ΦB0), ideality factor (n), flat-band barrier height (ΦBF) and series resistance (RS) values were evaluated and were found to be strongly temperature dependent. The results revealed that the ΦB0 values increase, whereas n, ΦFB and RS values decrease, with increasing temperature. Using the conventional Richardson plot, the mean barrier height (0.39 eV) and Richardson constant (8.10 × 10−10 Acm−2 K−2) were attained. The barrier height inhomogeneities were demonstrated by assuming a Gaussian distribution function. The interface state density (NSS) values were found to decrease with increasing temperature. The reverse leakage current mechanism of the V/p-GaN Schottky junction was found to be governed by Poole-Frenkel emission at all temperatures. [ABSTRACT FROM AUTHOR]

The electrical and frequency-dependent properties of ten Au/NiO/ n-GaN heterojunctions fabricated with similar conditions are assessed by I-V, C-V, and G-V measurement methods. In addition, C-f and G-f measurements are conducted in the frequency range of 1 kHz-1 MHz. The electronic parameters are changed from junction to junction even if they are fabricated in the similar way. The calculated barrier height and ideality factor values are fitted by the Gaussian distribution function. Statistical analysis of the data provides the mean barrier height and ideality factor values of 0.84 eV and 2.70 for the heterojunction. Besides, the mean barrier height ( Ф ), donor concentration ( N ), space charge layer width ( W ), and Fermi level ( E ) are determined from the C-V data and the corresponding values are 1.30 eV, 2.00 × 10 cm, 8.222 × 10 cm, and 0.018 eV, respectively. The interface state density ( N ) and relaxation time (τ) are assessed from C-f and G-f measurements. Moreover, the dielectric constant ( ε′), dielectric loss ( ε″), tangent loss (tan δ), and electrical conductivity ( σ ) are determined from C-f and G-f data in the frequency range of 1 kHz-1 MHz with various biases (0.1-0.6 V). ε′ and ε″ are decreased with increasing frequency. [ABSTRACT FROM AUTHOR]

The electrical properties of the Ir/Ru Schottky contacts on n-InGaN have been investigated by current-voltage ( I- V), capacitance-voltage ( C- V), capacitance-frequency ( C- f) and conductance-frequency ( G- f) measurements. The obtained mean barrier height and ideality factor from I- V are 0.61 eV and 1.89. The built-in potential, doping concentration and barrier height values are also estimated from the C- V measurements and the corresponding values are 0.62 V, 1.20 × 1017 cm and 0.79 eV, respectively. The interface state density ( N ) obtained from forward bias I- V characteristics by considering the series resistance ( R ) values are lower without considering the series resistance ( R ). Furthermore, the interface state density ( N ) and relaxation time (τ) are also calculated from the experimental C- f and G- f measurements. The N values obtained from the I- V characteristics are almost three orders higher than the N values obtained from the C- f and G- f measurements. The experimental results depict that N and τ are decreased with bias voltage. The frequency dependence of the series resistance ( R ) is attributed to the particular distribution density of interface states. [ABSTRACT FROM AUTHOR]

The temperature-dependent electrical properties of Ru/Ti/ n-InP Schottky diodes have been investigated in the temperature range of 120 to 400 K. The estimated barrier heights for the Ru/Ti/ n-InP Schottky barrier diode from the I- V and C- V characteristics vary from 0.24 to 0.73 eV ( I- V) and 0.94 to 0.74 eV ( C- V) and the ideality factor ( n) from 4.65 to 1.80 in the temperature range of 120-400 K. It has been observed that the ideality factor decreases while the barrier height increases with the increase in temperature. The barrier height ( Φ), ideality factor ( n) and series resistance ( R) of the Ru/Ti/ n-InP Schottky diode have been also determined using Cheung's and Norde methods. The discrepancy between the barrier heights obtained from the I- V and C- V characteristics is discussed. The interface state densities ( N) extracted for the Ru/Ti/ n-InP Schottky diode are in the range of 6.75 × 10 eV cm ( E-0.23 eV)-1.09 × 10 eV cm ( E-0.17 eV) at 120 K and 1.67 × 10 eV cm ( E-0.75 eV)-5.02 × 10 eV cm ( E -0.59 eV) at 400 K. It is observed that the interface state density ( N) decreases with increase in temperature. Results reveal that the conduction current is dominated by Poole-Frenkel emission in the temperature range from 120 to 320 K and by Schottky emission above 360 K. [ABSTRACT FROM AUTHOR]

Given two arithmetical functions f, g, we derive, under suitable conditions, asymptotic formulas for the convolution sums ∑ f ( n)( n + h) for a fixed number h. To this end, we develop the theory of Ramanujan expansions for arithmetical functions. Our results give new proofs of some old results of Ingham proved by him in 1927 using different techniques. [ABSTRACT FROM AUTHOR]