Electrical and optical study of Cu(In, Ga)Se2 co-evaporated thin films

Co-evaporation technique from three sources was used to prepare Cu(In, Ga)Se₂ polycrystalline thin films for photovoltaic conversion. Their conductivity was studied in the range 20–300 K. The grain boundary scattering mechanism is mainly responsible for the diffusion process in the latter materials. In the low temperature region, we interpret the data in terms of Mott law and the analysis is very consistent with the variable range hopping. However, thermoionic emission is predominant at high temperatures. When the conductivity deviates from the classical grain boundary conduction models, inhomogeneity is then considered and parameters such as the standard deviation and the mean potential barrier height are derived. Transmittance measurements yielded band gap values of 1.07 and 1.64 eV for CuInSe₂ and CuGaSe₂, respectively.     

Supervised Multi‐Rejector of Periodic Disturbances for Nonlinear Systems Using Decoupled State Multimodel

In this paper, a multi‐rejector of periodic disturbances is proposed for discrete‐time nonlinear systems represented by a decoupled state multimodel. We report a decoupled state multimodel repetitive‐predictive control based on a supervised algorithm to ensure reference trajectory tracking and periodic disturbances rejection. Partial predictors associated to the local controllers make the best choice of the most valid partial controller that meets the desired closed loop performances. The effectiveness of the supervised multi‐rejector is shown via a simulation example. The obtained results are satisfactory and show a good rejection of periodic disturbances and reference trajectory tracking.     

Optimal Deep Learning Based Intruder Identification in Industrial Internet of Things Environment

With the increased advancements of smart industries, cybersecurity has become a vital growth factor in the success of industrial transformation. The Industrial Internet of Things (IIoT) or Industry 4.0 has revolutionized the concepts of manufacturing and production altogether. In industry 4.0, powerful Intrusion Detection Systems (IDS) play a significant role in ensuring network security. Though various intrusion detection techniques have been developed so far, it is challenging to protect the intricate data of networks. This is because conventional Machine Learning (ML) approaches are inadequate and insufficient to address the demands of dynamic IIoT networks. Further, the existing Deep Learning (DL) can be employed to identify anonymous intrusions. Therefore, the current study proposes a Hunger Games Search Optimization with Deep Learning-Driven Intrusion Detection (HGSODL-ID) model for the IIoT environment. The presented HGSODL-ID model exploits the linear normalization approach to transform the input data into a useful format. The HGSO algorithm is employed for Feature Selection (HGSO-FS) to reduce the curse of dimensionality. Moreover, Sparrow Search Optimization (SSO) is utilized with a Graph Convolutional Network (GCN) to classify and identify intrusions in the network. Finally, the SSO technique is exploited to fine-tune the hyper-parameters involved in the GCN model. The proposed HGSODL-ID model was experimentally validated using a benchmark dataset, and the results confirmed the superiority of the proposed HGSODL-ID method over recent approaches.     

Inflammation,Oxidative Stress,Senescence in Atherosclerosis: Thioredoxine-1 as an Emerging Therapeutic Target

Atherosclerosis is a leading cause of cardiovascular diseases (CVD) worldwide and intimately linked to aging. This pathology is characterized by chronic inflammation, oxidative stress, gradual accumulation of low-density lipoproteins (LDL) particles and fibrous elements in focal areas of large and medium arteries. These fibrofatty lesions in the artery wall become progressively unstable and thrombogenic leading to heart attack, stroke or other severe heart ischemic syndromes. Elevated blood levels of LDL are major triggering events for atherosclerosis. A cascade of molecular and cellular events results in the atherosclerotic plaque formation, evolution, and rupture. Moreover, the senescence of multiple cell types present in the vasculature were reported to contribute to atherosclerotic plaque progression and destabilization. Classical therapeutic interventions consist of lipid-lowering drugs, anti-inflammatory and life style dispositions. Moreover, targeting oxidative stress by developing innovative antioxidant agents or boosting antioxidant systems is also a well-established strategy. Accumulation of senescent cells (SC) is also another important feature of atherosclerosis and was detected in various models. Hence, targeting SCs appears as an emerging therapeutic option, since senolytic agents favorably disturb atherosclerotic plaques. In this review, we propose a survey of the impact of inflammation, oxidative stress, and senescence in atherosclerosis; and the emerging therapeutic options, including thioredoxin-based approaches such as anti-oxidant, anti-inflammatory, and anti-atherogenic strategy with promising potential of senomodulation.     

On the ultrathin gold film used as buffer layer at the transparent conductive anode/organic electron donor interface

Previously, we have shown that a gold thin film of only 0.5 nm introduced at the interface between the indium tin oxide or ZnO anode and the organic electron donor in organic photovoltaic cells induces a strong improvement of the cell efficiency. Of course a thickness of 0.5 nm corresponds only to an averaged thickness, the films being too thin to be continuous. For a clear understanding of the physical mechanisms that are responsible for this improved behaviour, it is important to know the fractional coverage and the island height of this thin Au film. In the present work, we have used two different techniques, such as treated scanning electron microscope images and analysis of the inelastic part of peaks of X-ray photoelectron spectroscopy spectra, to estimate the gold coverage and island height of the transparent conductive anode. There is an excellent agreement between the results achieved by both methods. Only 15% of the anode is covered, which proves the high efficiency of gold as an anode buffer layer in organic photovoltaic devices.     

Production of Nanoparticles in Thermal Plasmas: A Model Including Evaporation,Nucleation, Condensation,and Fractal Aggregation

In this work a coupled model for the production of nanoparticles in an inductively coupled plasma reactor is proposed. A Lagrangian approach is used to describe the evaporation of precursor particles and an Eulerian model accounting for particle nucleation, condensation, and fractal aggregation. The models of the precursor and nanoparticles are coupled with the magneto-hydrodynamic equations describing the plasma. The purpose of this study is to develop a model for the synthesis of particles in a thermal plasma reactor, which can be used to optimize industrial reactors. The growth of aggregates is considered by introducing a power law exponent D _f. Results are compared qualitatively and quantitatively with existing experimental data from plasma reactors at a relatively large laboratory scale. The results obtained from the model confirm the previously observed importance of the quench strategy in defining the morphology of the nanoparticles.     

Microstructural properties of ZnO:Sn thin films deposited by intermittent spray pyrolysis process

Zinc oxide films have been prepared via spray pyrolysis using a perfume atomizer. ZnCl₂ has been used as precursor. The influence of the precursor solution and dopant concentration has been investigated. Homogeneous films are obtained with a precursor concentration ranging between 0.3 and 0.4 M and a SnCl₂ dopant concentration of 1–2%. The films exhibit broad band gaps and small conductivity. The microstructural properties of these films have been compared with that of films deposited using a classical nozzle. Films deposited by perfume atomizer are rougher, with smaller grain size, compared to films deposited with a classical nozzle.     

Transport properties in polypyrrole–PVA composites: Evidence for hopping conduction

Experimental results on electrical conductivity and thermoelectric power for FeCl₃-doped polyvinyl alcohol-polypyrrole composites, with polypyrrole content exceeding the percolation threshold, are presented. The electrical conductivity is analyzed in terms of the hopping theory, whereas the thermoelectric power displays a metallic-like dependence. A model involving both the intrinsic resistance of the fibrils (V.R.H. hopping mechanisms) and the resistance of the junctions between fibrils (fluctuations-induced tunneling conduction) has been retained.     

Positively equicontinuous flows

Let G be a positively equicontinuous flow of homeomorphisms of a locally compact metric space E. We show how the dynamics of such a flow are rich. We study when regularly almost periodic elements in G are periodic and we describe orbits and their limit sets. In particular, we show that the limit set L(G?) of G is a closed subset on which G is equicontinuous and that if G moreover has closed orbits, then any w-limit set is a periodic orbit.     

Stability of electrical properties in polyaniline-polystyrene blends

The thermal stability of free standing polystyrene-polyaniline-DiOHP blend electrical properties is described. Electrical conductivity measurements have been performed at different temperatures for a long degradation time. A good stability with time and temperature is observed. The electrical conductivity variations versus temperature are explained on the assumption of a main contribution of hopping mechanisms between conducting clusters.