Ac-electronic and dielectric properties of semiconducting Phthalocyanine compounds: A comparative study

The AC-electronic and dielectric properties of different phthalocyanine films(ZnPc,CuPc,FePc,and H2Pc)were investigated over a wide range of temperature.Both real and imaginary parts of the dielectric constant("D"1–i"2/were found to be influenced by temperature and frequency.Qualitatively the behavior was the same for those compounds;however,the central atom,film thickness,and the electrode type play an important role in the variation of their values.Therelaxationtime,,wasstronglyfrequency-dependentatalltemperaturesandlowfrequencies,whileaweak dependency is observed at higher frequencies.The relaxation activation energy was derived from the slopes of the fitted lines of ln and the reciprocal of the temperature(1/T).The values of the activation energy were accounted forthehoppingprocessatlowtemperatures,whileathermallyactivatedconductionprocesswasdominantathigher temperatures.Themaximumbarrierheight,Wm,wasfoundtobetemperatureandfrequencydependentforallphthalocyanine compounds.The value Wm depends greatly on the nature of the central atom and electrode material type.The correlated barrier hopping model was found to be the appropriate mechanism to describe the charge carrier’s transport in phthalocyanine films.     

缝纫针使用时间对缝制质量的影响

缝纫针是缝纫机上的一个小部件,但它对缝纫质量起着十分重要的作用,并最终影响缝纫外观。从缝纫强力和线迹弹伸性两方面论述了缝纫针的使用时间对缝制质量的影响。     

Étude de la génération d’impulsions brèves d’un laser DFB à trois contrôles de phases (3QWS-DFB)

The purpose of this paper is to study the generation of short pulses of the three quarter wave shift distributed feedback (3Qws-dfb) laser by using switching gain technique. We have used the temporal domain model (Tdm) which is a multimode spatio-temporal model that considers simultaneously all the modes of the overall intra-cavity field as well as the two following nonlinear effects, the spectral hole burning (Shb) and the gain saturation. Obtained results showed that a 3Qws-dfb laser can generate short pulses in accordance with Fourier criteria. These results show that 3Qws-dfb lasers are potential candidates as monomode optical sources for long distance high bit rate telecommunications.     

Circularly Polarized Emission from Ensembles of InGaAs/GaAs Quantum Rings

Magneto-photoluminescence spectroscopy measurements were performed on self-assembled InGaAs/GaAs quantum rings. We report exciton exchange energy as a function of interband emission energy; we measure a decrease from 163 μ e V to 43 μ e V in the range of 1.30 eV to 1.40 eV. This result is remarkable and compatible with the exciton exchange energy in self-assembled InAs/GaAs quantum dots. Our results reveal the high value of exciton exchange albeit the quantum rings shape. We show that the exciton energy is sensitive to a magnetic field.     

Uniqueness of asymptotic solution for general Markov fluid models

We investigate the asymptotic workload distribution of fluid models with input and output rates which are modulated by an irreducible Markov process. An analytical solution is proposed in [H. Nabli, Asymptotic solution of stochastic fluid models, Perform. Eval. 57 (2004) 121–140] for general Markov fluid model. This probability distribution is controlled by a linear differential system with specific boundary conditions. The solution uniqueness is proved under a conjecture in the field of linear algebra. This conjecture is valid for all particular fluid models considered in the literature. In this paper, we will prove this conjecture for general fluid models. The numerical computation of the stationary distribution will be also discussed.     

Spatiotemporal data mining: a survey on challenges and open problems

Spatiotemporal data mining (STDM) discovers useful patterns from the dynamic interplay between space and time. Several available surveys capture STDM advances and report a wealth of important progress in this field. However, STDM challenges and problems are not thoroughly discussed and presented in articles of their own. We attempt to fill this gap by providing a comprehensive literature survey on state-of-the-art advances in STDM. We describe the challenging issues and their causes and open gaps of multiple STDM directions and aspects. Specifically, we investigate the challenging issues in regards to spatiotemporal relationships, interdisciplinarity, discretisation, and data characteristics. Moreover, we discuss the limitations in the literature and open research problems related to spatiotemporal data representations, modelling and visualisation, and comprehensiveness of approaches. We explain issues related to STDM tasks of classification, clustering, hotspot detection, association and pattern mining, outlier detection, visualisation, visual analytics, and computer vision tasks. We also highlight STDM issues related to multiple applications including crime and public safety, traffic and transportation, earth and environment monitoring, epidemiology, social media, and Internet of Things.

     

Observer design for induction motor: an approach based on the mean value theorem

In this paper, observer design for an induction motor has been investigated. The peculiarity of this paper is the synthesis of a mono-Luenberger observer for highly coupled system. To transform the nonlinear error dynamics for the induction motor into the linear parametric varying (LPV) system, the differential mean value theorem combined with the sector nonlinearity transformation has been used. Stability conditions based on the Lyapunov function lead to solvability of a set of linear matrix inequalities. The proposed observer guarantees the global exponential convergence to zero of the estimation error. Finally, the simulation results are given to show the performance of the observer design.     

Synthesis and corrosion inhibition evaluation of a new schiff base hydrazone for mild steel corrosion in HCl medium: electrochemical,DFT, and molecular dynamics simulations studies

Abstract

The development of cost-effective, sustainable, eco-friendly and efficient compounds is a renovated science and a demanding assignment for today’s chemists and technology specialists. In this context, the anticorrosion effect of a new Schiff base hydrazone, namely (E)-2-(4-(2-(methyl(pyridin-2-yl)amino)ethoxy)benzylidiene)hydrazine-1-carboxamide (MPAH) against the mild steel (MS) surface in 1.0?M HCl has been analyzed utilizing experimental methods, thermodynamic characterizations, and computational studies. MPAH has proven to be an effective inhibitor in 1.0?M HCl solution. Its inhibition performance improved by raising the concentration of the compound to an optimal concentration of 5?×?10^?3 M, and 97% efficiency was achieved at 303?K. Inhibitor adsorption on the MS has been explicated with both physical and chemical interactions. The adsorption was in accordance with the isotherm of Langmuir. The impact of MPAH on the surface of MS had been confirmed utilizing SEM/EDX, electrochemical impedance spectroscopy (EIS), gravimetric measurements (WL), and potentiodynamic polarization (PDP). The adsorption of the studied compound on the MS surface has also been investigated by DFT and the molecular dynamics (MD) simulations.