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141.
We suggest a method for determining the number of an eigenvalue of a self-adjoint spectral problem nonlinear with respect
to the spectral parameter, for some class of Hamiltonian systems of ordinary differential equations on the half-line. The
standard boundary conditions are posed at zero, and the solution boundedness condition is posed at infinity. We assume that
the matrix of the system is monotone with respect to the spectral parameter. The number of an eigenvalue is determined by
the properties of the corresponding nontrivially solvable homogeneous boundary value problem. For the considered class of
systems, it becomes possible to compute the numbers of eigenvalues lying in a given range of the spectral parameter without
finding the eigenvalues themselves. 相似文献
142.
M. Wasim W. A. Zafar M. Tufail M. Arif M. Daud A. Ahmad 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):821-826
To study the impurity elements, which render color-induced topaz long lived radionuclides, three samples of topaz, from three
different cities of the Northern Pakistan (Baltistan, Gilgit and Mardan) were analyzed using k
0 instrumental neutron activation analysis (k
0-INAA). The samples were irradiated in Pakistan Research Reactor-1 (PARR-1) and PARR-2 at Pakistan Institute of Nuclear Science
& Technology (PINSTECH), Islamabad. The method was validated by analyzing IAEA-S7 reference material. In three samples a total
of 22 trace level impurity elements were quantified. Among impurities, 10 elements including As, Ce, Ga, Ge, La, Na, Sb, Sc,
U and Zn were common in topaz of all the three places. The storage time has been calculated for each sample required to bring
the induced radioactivity down to permissible level given by US National Regulatory Commission. 相似文献
143.
Saeed Ul Haq Raz Muhammad Afaf Khadr Alqorashi Muhammad Shafiullah Amir Sohail Amel Laref Muhammad Faizan 《International journal of quantum chemistry》2024,124(3):e27353
We investigated the magnetic and thermoelectric properties of REMoN3 (RE = La, Ce, Pr, Nd, Sm) perovskites using the full potential linearized augmented plane wave (FP-LAPW) method. To overcome the problem of underestimation of electronic interaction, we employed the DFT + U approach to accurately map the electronic structure of these compounds. Our study shows an increasing trend in the magnetic moments with the increasing number of unpaired electrons in RE. Among these compounds, SmMoN3 possesses a large magnetic moment, which is suitable for applications such as memory devices and sensors. Interestingly, all these perovskites display ferromagnetic behavior except CeMoN3, which exhibits an antiferromagnetic nature. Furthermore, our analysis indicates n-type thermoelectric behavior in all these materials. The compound, namely PrMoN3, exhibits a high figure of merit among REMoN3, which can be improved by modifying the lattice sites. 相似文献
144.
We consider a general self-adjoint spectral problem, nonlinear with respect to the spectral parameter, for linear differential-algebraic
systems of equations. Under some assumptions, we present a method for reducing such a problem to a general self-adjoint nonlinear
spectral problem for a system of differential equations. In turn, this permits one to pass to a problem for a Hamiltonian
system of ordinary differential equations. In particular, in this way, one can obtain a method for computing the number of
eigenvalues of the original problem lying in a given range of the spectral parameter. 相似文献
145.
S. V. Kuzin S. A. Bogachev I. A. Zhitnik S. V. Shestov V. A. Slemzin A. V. Mitrofanov N. K. Sukhodrev A. A. Pertsov A. V. Ignat’ev O. I. Bugaenko Yu. S. Ivanov A. A. Reva M. S. Zykov A. S. Ul’yanov S. N. Oparin A. L. Goncharov T. A. Shergina A. M. Urnov V. A. Solov’ev S. G. Popova 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(1):33-37
The CORONAS-Photon spacecraft was successfully launched in January 2009. Its scientific payload included the TESIS complex of telescopes and spectrometers, designed to obtain high spectral, temporal and spatial resolution solar corona images in soft X-ray to far UV spectral range. 相似文献
146.
Nazar Ul Islam Kamran Jalil Muhammad Shahid Naveed Muhammad Abdur Rauf 《Arabian Journal of Chemistry》2019,12(8):2310-2319
This paper reports a rapid, facile and one-pot synthesis of environmentally safe gold nanoparticles capped and stabilized with galls extract of Pistacia integerrima. The aqueous gold ions when exposed to P. integerrima galls extract were rapidly reduced as evident from abrupt color change to ruby red, suggesting the biosynthesis of gold nanoparticles (Au-NPs) which were further characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Their stability was evaluated against varying pH and different volumes of sodium chloride (NaCl) as well as at a range of temperature (20–80 °C). Au-NPs were tested for enzyme inhibition, antibacterial, antifungal, antinociceptive, muscle relaxant and sedative activities. The UV–Vis spectra of the gold nanoparticles gave surface plasmon resonance at 540 nm while the SEM analysis revealed the particle size in the range of 20–200 nm. FTIR spectra confirmed the involvement of amines, amide groups and alcohols in capping and reduction of gold nanoparticles. Au-NPs showed remarkable stability in different NaCl and pH solutions as well as at elevated temperature. Au-NPs have good antifungal activity and possessed antinociceptive and muscle relaxant properties as observed from their zone of inhibition and significant attenuation of acetic acid induced writhing and reduction of time spent on the rota rod respectively. These results concluded that the gall extract of P. integerrima is a very good bioreductant for the synthesis of gold nanoparticles that have potential for various biomedical and pharmaceutical applications. 相似文献
147.
Sami Ul Haq Muhammad Atif Khan Nehad Ali Shah 《Chinese Journal of Physics (Taipei)》2018,56(1):261-269
The aim of this paper is to investigate the exact general solutions of the incompressible viscous fluid flow by using the time-fractional Caputo–Fabrizio derivative. The flow of the fluid is subject to the motion of a plane wall, embedded in a porous medium under the influence of magnetic field. The corresponding non-dimensional governing fractional differential equation with appropriate initial and boundary conditions is solved by means of integral transforms namely, Laplace and Fourier transforms. Solutions are expressed as a sum of steady and transient parts, for the sinusoidal oscillations of the plane wall. The influence of involved physical parameters are discussed graphically. Specifically, it has been observed that the effective permeability Keff reduces the time taken to reach the steady state. 相似文献
148.
Sajid-ur- Rehman Faheem K. Butt Chuanbo Li Bakhtiar Ul Haq Zeeshan Tariq F. Aleem 《Frontiers of Physics》2018,13(3):137805
This study is focused on calculation of the electronic structure and optical properties of non-metal doped Sb2Se3 using the first-principles method. One and two N atoms are introduced to Sb and Se sites in a Sb2Se3 crystal. When one and two N atoms are introduced into the Sb2Se3 lattice at Sb sites, the electronic structure shows that the doping significantly modifies the bandgap of Sb2Se3 from 1.11 eV to 0.787 and 0.685 eV, respectively. When N atoms are introduced to Se sites, the material shows a metallic behavior. The static dielectric constants ε1(0) for Sb16Se24, Sb15N1Se24, Sb14N2Se24, Sb16Se23N1, and Sb16Se22N2 are 14.84, 15.54, 15.02, 18.9, and 39.29, respectively. The calculated values of the refractive index n(0) for Sb16Se24, Sb15N1Se24, Sb14N2Se24, Sb16Se23N1, and Sb16Se22N2 are 3.83, 3.92, 3.86, 4.33, and 6.21, respectively. The optical absorbance and optical conductivity curves of the crystal for N-doping at Sb sites show a significant redshift towards the short-wave infrared spectral region as compared to N-doping at Se sites. The modulation of the static refractive index and static dielectric constant is mainly dependent on the doping level. The optical properties and bandgap narrowing effect suggest that the N-doped Sb2Se3is a promising new semiconductor and can be a replacement for GaSb due to its very similar bandgap and low cost. 相似文献
149.
Wasiq Ali Yaan Li Muhammad Asif Zahoor Raja Wasim Ullah Khan Yigang He 《Entropy (Basel, Switzerland)》2021,23(9)
In this study, an application of deep learning-based neural computing is proposed for efficient real-time state estimation of the Markov chain underwater maneuvering object. The designed intelligent strategy is exploiting the strength of nonlinear autoregressive with an exogenous input (NARX) network model, which has the capability for estimating the dynamics of the systems that follow the discrete-time Markov chain. Nonlinear Bayesian filtering techniques are often applied for underwater maneuvering state estimation applications by following state-space methodology. The robustness and precision of NARX neural network are efficiently investigated for accurate state prediction of the passive Markov chain highly maneuvering underwater target. A continuous coordinated turning trajectory of an underwater maneuvering object is modeled for analyzing the performance of the neural computing paradigm. State estimation modeling is developed in the context of bearings only tracking technology in which the efficiency of the NARX neural network is investigated for ideal and complex ocean environments. Real-time position and velocity of maneuvering object are computed for five different cases by varying standard deviations of white Gaussian measured noise. Sufficient Monte Carlo simulation results validate the competence of NARX neural computing over conventional generalized pseudo-Bayesian filtering algorithms like an interacting multiple model extended Kalman filter and an interacting multiple model unscented Kalman filter. 相似文献
150.
Mechanical and thermodynamical stability of BiVO_4 polymorphs using first-principles study
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A K M Farid Ul Islam Md Nurul Huda Liton H M Tariqul Islam Md Al Helal Md Kamruzzaman 《中国物理 B》2017,26(3):36301-036301
First principles calculations of structural, electronic, mechanical, and thermodynamic properties of different polymorphs of BiVO_4 are performed using Bender-type plane/wave ultrasoft pseudopotentials within the generalized gradient approximation(GGA) in the frame of density functional theory(DFT). The calculated structural and electronic properties are consistent with the previous theoretical and experimental results. The electronic structures reveal that m-BiVO_4, opBiVO_4, and st-BiVO_4 have indirect band gaps, on the other hand, zt-BiVO_4 has a direct band gap. From the DOS and Mulliken's charge analysis, it is observed that only m-BiVO_4 has 6s~2Bi lone pair. Bond population analysis indicates that st-BiVO_4 shows a more ionic nature and a similar result is obtained from the elastic properties. From the elastic properties, it is observed that st-BiVO_4 is more mechanically stable than the others. st-BiVO_4 is more ductile and useful for high electro-optical and electro-mechanical coupling devices. Our calculated thermodynamic properties confirm the similar characteristics found from electronic and elastic properties. m-BiVO_4 is useful as photocatalysts, solid state electrolyte,and electrode and other polymorphs are applicable in electronic device fabrications. 相似文献