Reliable Characteristics Research Articles

Ti-doped alumina based reliable resistive switching in sub- μ A regime

We investigated the low current resistive switching behavior using Ti-doped Al2O3 and sub-stoichiometric TaOx layers. The optimized concentrations of Ti and O in each Al2O3 and TaOx layer can make the resistive switching device show the stable retention characteristic and 3-bit operation in the current regime under 1 μA. Doped Ti in the Al2O3 layer generated oxygen vacancies to facilitate fluent resistive switching, and the TaOx layer with an appropriate oxygen concentration played the role of an oxygen reservoir and load resistance for reliable retention and electric pulse compatible characteristics, respectively. We presented the materials optimization processes and comparative resistive switching characteristics in detail.

Enhancement of data storage capability in a bilayer oxide-based memristor for wearable electronic applications

In this work, a ZnO/NiO bilayer architecture is introduced to fabricate a transparent and flexible resistive random access memory device (Cu/ZnO/NiO/ITO) on polyethylene terephthalate substrate. The device exhibits excellent resistive switching (RS) characteristics, such as forming-free characteristic, low operating voltages, outstanding uniformity, long retention time (>104 s), high ON/OFF current ratio ~103, reliable multilevel cell characteristics and excellent mechanical flexibility. The multilevel properties have been systematically evaluated by varying the compliance current and tuning the stopping voltage, which shows that the whole resistance state is distinguishable and remained stable without any considerable deprivation over 103 s. Intrinsic tailoring of RS mechanism has been well explained in the framework of electric field-induced formation and rupture of the reproducible Cu filaments in ZnO/NiO layer. Furthermore, the metallic nature of conducting filament has been confirmed by temperature-dependent variation of the high- and low-resistance states. Due to the increasing demand for flexible electronics, the mechanical robustness of the proposed device has been examined by varying the bending time and radius. The present RS device shows potential towards integration in many transparent, flexible and high-density storage devices, such as electronic skins and flexible displays.

A simulation approach to the spectral quality of multispectral images enhancement

The accuracy of environmental research with the use of remote sensing methods depends upon the quality of image data. Hence the acquisition of images of high spatial and spectral quality simultaneously is of crucial importance. To resolve the problem of structural limitations of sensors that influence the quality of acquired images, it is necessary to integrate data from different sensors. Using both original and simulated high spatial resolution images, the authors proposed an effective methodology for integrating image data from aerial and satellite sensors, allowing the generation of sharpened images while maintaining the highest degree possible of the spectral features of photographed objects. At the same time, the article concerns the impact assessment of spectral resolution of high spatial images upon the spectral quality of an enhanced image in multisensor data fusion process with the use of the pan-sharpening method. It is of extreme importance from the viewpoint of precision farming, where it is necessary to have as many parameters as possible that characterise agricultural and forest land. Moreover, the aim is for such parameters to reflect the reliable spectral characteristics of the studied objects.Increased spectral quality of sharpened images translates not only to more credible quantitative evaluation of photographed land-use areas, including but not limited to the assessment of the condition of plants, as well as to more accurate automatic plant classification process.

Benzoselenadiazole-Based Conjugated Molecules: Active Switching Layers with Nanofibrous Morphology for Nonvolatile Organic Resistive Memory Devices.

In this work, two symmetrical donor-acceptor-donor (D-A-D) type benzoselenadiazole (BSeD)-based π-conjugated molecules were synthesized and employed as an active switching layer for non-volatile data storage applications. BSeD-based derivatives with different donor units attached through common vinylene linkers showed different electrical and optical properties. 4,7-Di((E)-styryl)benzo[c][2,1,3]selenadiazole (DSBSeD) and 4,7-bis((E)-4-methoxystyryl)benzo[c][2,1,3]selenadiazole (DMBSeD) are sandwiched between gallium-doped ZnO (GZO) and metal aluminum electrodes respectively through solution-processed spin-coating method. The solution-processed nanofibrous switching layer containing the DMBSeD-based memory device showed reliable memory characteristics in terms of write and erase operations with low SET voltage than the random-aggregated DSBSeD-based device. The nanofibrous molecular morphology of switching layer overcomes the interfacial hole transport energy barrier at the interface of the DMBSeD thin-film and the bottom GZO electrode. The memory device GZO/DMBSeD/Al based on nanofibrous switching layers shows switching characteristics at compliance current of 10 mA with Vset =0.79 V and Vreset =-0.55 V. This work will be beneficial for the rational design of advanced next-generation organic memory devices by controlling the nanostructured morphology of active organic switching layer for enhanced charge-transfer phenomenon.

Stabilized and RESET-voltage controlled multi-level switching characteristics in ZrO2-based memristors by inserting a-ZTO interface layer

Abstract Transition metal oxides based memristors possess multi-resistance states and can be used as a main source for memory devices. However, variability in resistive switching (RS) characteristics is a major issue for the application of memristor devices in emerging information computing system. The achievement of stable switching between high resistance state (HRS) and low resistance states (LRS) has become an important task for their implementation and industrial production. In this study, issues of oxygen accumulation and variations in the HRS of single layer (SL) Ta/ZrO2/TiN memristor devices, stability of HRS and concentrated distribution of SET-voltages were realized by inserting a thin amorphous zinc-tin-oxide (a-ZTO) film between the TiN bottom electrode and ZrO2 RS layer. With this bilayer (BL) Ta/ZrO2/a-ZTO/TiN memristor device, stabilized RS properties, such as ON/OFF ratio >102, smaller forming voltages, uniform SET-/RESET-voltages, and good pulse switching endurance (>105 cycles) have been demonstrated as compared to SL memristor devices. In addition, BL memristor device also exhibited four distinct resistance levels (three high resistance levels with same LRS) by adjusting RESET-stop voltages, and each level showed multilevel endurance and reliable retention characteristics. The current transport mechanism has been investigated at HRS of different RESET-stop voltages (i.e. 1.5 V, 1.7 V and 1.9 V), which confirms that Schottky barrier height increases by increasing the RESET-voltages. Finally, a conducting model was proposed to illuminate the effect of a-ZTO thin layer and to explain the physical mechanism of stabilized RS behavior.

Just‐in‐time learning for the prediction of oil sands ore characteristics using GPS data in mining applications

AbstractFor the mining based oilsands industry, it is desirable to determine the quality of the ore delivered to the extraction processes in real‐time to make optimal operational decisions such as optimal ore blending to achieve maximal bitumen recovery. Currently, the industry determines the real‐time ore characteristics for any given shovel Global Positioning System (GPS) location by first determining the shovel elevation from the topological mine map and then using the determined geological coordinates in the 3D geological block model. It should be noted that the block model is built based on the widely spaced core hole samples, and it is updated only on a yearly basis due to high cost of narrower core hole sampling. Thus, the block model predictions are often inaccurate in between the core hole spacing. On the other hand, mining operations data are available that contain accurate ore characteristics information in the already mined area. Therefore, in this work, we present a just‐in‐time based data‐driven modelling strategy that utilizes the recently available mining operations data to obtain reliable ore characteristics given the GPS data. The prediction capability of ore characteristics using the proposed modelling strategy is validated at core hole locations. Further, the prediction of ore characteristics at non‐core hole points demonstrate promising results.

Flexible and fully biodegradable resistance random access memory based on a gelatin dielectric

The increased public concerns on healthcare, the environment and sustainable development inspired the development of biodegradable and biocompatible electronics that could be used as degradable electronics in implants. In this work, a fully biodegradable and flexible resistance random access memory (RRAM) was developed with low-cost biomaterial gelatin as the dielectric layer and the biodegradable polymer poly(lactide-coglycolide) acid (PLGA) as the substrate. PLGA can be synthesized by a simple solution process, and the PLGA substrate can be peeled off the handling substrate for operation once the devices are fabricated. The fabricated memory devices exhibited reliable nonvolatile resistive switching characteristics with a long retention time over 104 s and a near-constant on/off resistance ratio of 102 even after 200 bending cycles, showing the promising potential for application in flexible electronics. Degradation of the devices in deionized water and in phosphate buffered saline (PBS) solution showed that the whole devices can be completely degraded in water. The dissolution time of the metals and the gelatin layer was a few days, while that for PLGA is about 6 months, and can be modified by changing the synthesis conditions of the film, thus allowing the development of biodegradable electronics with designed dissolution time.

A study of dynamic response of a wind turbine blade based on the multi-body dynamics method

The geometric nonlinear problem caused by large deformation and the aeroelastic issue under extreme wind conditions are becoming more and more prominent, as the flexibility of wind turbine blades enhances. To solve this problem, a model of Blade analysis with Multi-Body (BaMB) method is built by the rigid multi-body dynamics method in absolute coordinates. The model describes geometric nonlinearity and complex geometry of blades, and accurate results can be obtained by the model after blades are reasonably divided. Based on this model, the geometric nonlinearity of a 100 kW blade under static loading and the aeroelastic response under extreme operating gust (EOG) condition are investigated numerically and compared with experimental results. The results show that BaMB model is able to predict more accurate deformation than beam models under static loading when the deformation of the blade increases, especially when the blade is loaded with more than 120% of the maximum design load and the tip deflection is larger than 15.36% of the blade spans. At 210% of the maximum design load, the BaMB model can predict the deformation at the accuracy of 1.48% with respect to the test; however, the accuracies of the Euler-Bernoulli beam and the Timoshenko beam are 18.3% and 16.79%, respectively. Even in the case of large deformation, the BaMB model can reach the accuracy close to the finite element method (FEM) with high computational efficiency. The aeroelastic response of the blade under EOG condition is analyzed, and the results show that the BaMB model predicts reliable aeroelastic characteristics of the blade compared with commercial software.

Metal-oxide interface reactions and their effect on integrated resistive/threshold switching in NbOx

Reactive metal electrodes (Nb, Ti, Cr, Ta, and Hf) are shown to play an important role in controlling the volatile switching characteristics of metal/Nb2O5/Pt devices. In particular, devices are shown to exhibit stable threshold switching under negative bias but to have a response under positive bias that depends on the choice of metal. Three distinct responses are highlighted: Devices with Nb and Ti top electrodes are shown to exhibit stable threshold switching with symmetric characteristics for both positive and negative polarities; devices with Cr top electrodes are shown to exhibit stable threshold switching but with asymmetric hysteresis windows under positive and negative polarities; and devices with Ta and Hf electrodes are shown to exhibit an integrated threshold-memory (1S1M) response. Based on thermodynamic data and lumped element modelling these effects are attributed to the formation of a metal-oxide interlayer and its response to field-induced oxygen exchange. These results provide important insight into the physical origin of the switching response and pathways for engineering devices with reliable switching characteristics.

Improved on-state resistance with reliable reverse characteristics in 1.2 kV 4H-SiC MOSFET by selective nitrogen implantation assisted current spreading layer

In this study, we developed a superior 1.2 kV 4H-SiC metal-oxide-semiconductor field-effect transistor (MOSFET) with epi-grown current spreading layer (CSL) assisted by selective nitrogen implantation. This MOSFET is experimentally demonstrated to have improved on-state resistance with reliable reverse characteristics compared to the MOSFET which adopts conventional single CSL (epi-grown or implanted only). Based on the systematic study of SiC MOSFETs with epi-grown CSLs, it was found that the global high donor concentration of epi-grown CSLs weakens the blocking performance of edge termination structure in the peripheral region. Incorporation of nitrogen-implantation at the active region in epi-grown CSL can reduce the specific on-state resistance by 1 mΩ cm2 without degradation in the edge termination.

Information security system model in the automated system developed in the simulation software environment CPN Tools

This article through simulation provides the functioning mathematical model of information security system (ISS) from unauthorized access (UAA) in automated systems (AS). The model is developed in CPN Tools software environment for its analysis, getting probabilistic-temporal characteristics and its further comparison with the analytical model. The systematic analysis of functional components in ISS from UAA highlighted its key subsystems. Integrated CPN Tools breaks the model into subsystems by preserving ISS functioning logics from UAA, and observes the taking processes. This model performs the computation experiment, namely, researches ISS real consumer properties from UAA in AS, which in following researches provides the analysis software complex development and qualitative assessment of the similar systems functioning. Simulation results of ISS functioning process from UAA in AS can be various characteristics of each state, describing the system work both generally and for its subsystems. The programming Metalanguage, used in CPN Tools adjusts the simulation model and controls the marker random transition from the initial state to final through intermediate, determines transition properties, enters different marker types, sets time delays, etc. The article substantiates the required transitions by ISS simulation model from UAA in AS to get reliable characteristics as the further research direction.

Studying the influence of the thermoelectric materials parameters on the dynamics of single­cascade cooling devices

The effect of the variants of parameters of the original thermoelectric materials of the same efficiency on the operational dynamics of a single-cascade thermoelectric cooler has been examined. The variants differ by the coefficients of thermoEMF, electrical conductivity, and thermal conductivity. The study has been carried out in the range of changes in the working temperature, the rated heat load at the predefined geometry of thermoelement branches.The analysis was performed for the characteristic current modes of operation: maximum refrigerating capacity Q0max, maximum refrigerating capacity at the predefined current (Q0/I)max, maximum refrigerating factor (Q0/I2)max, minimum failure rate λmin.We have established the relationship between the cooler dynamics and the basic parameters and reliability indicators for different current modes of operation. A possibility has been shown to reduce the time to enter a stationary mode of operation for a variant with the increased electrical conductivity of a material, by 9‒10 %, compared to the basic variant calculated for the averaged electrophysical parameters. The minimum time to enter a stationary regime is achieved under a mode of maximum refrigerating capacity.The economic feasibility of using the starting source materials with enhanced electric conductivity relates not only to the improved dynamic and reliable characteristics. Designing thermoelectric coolers is also associated with a decrease in the cost of a cooler by using materials that were considered substandard.The rational design of thermoelectric coolers for the systems that enable the thermal modes of electronic equipment accounts for a set of restrictive requirements. These include energy consumption, weight, and size, performance speed, reliability indicators, etc., which are inherently contradictory. The proposed selection of compromise variants of the current modes of operation for different operating conditions allows the optimized design of thermally-loaded equipment

Water Vapor Permeability through Porous Polymeric Membranes with Various Hydrophilicity as Synthetic and Natural Barriers.

The article is devoted to the analysis of sorption kinetics, permeability, and diffusion of water vapor in porous polymeric membranes of different hydrophilicities and through-porosities. The water transport measurement with a constant gradient of partial pressure allows the authors to obtain reliable characteristics for porous membranes, films, artificial leathers, and fabrics of various chemical natures (synthetic and bio-based) and phase structures. All the kinetic permeability curves were determined and effective diffusion coefficients, as well as their apparent activation energies, were calculated at the stationary and non-stationary stages of the mass transfer. The relationship between the sorption–diffusion characteristics of the polymer barriers and their vapor permeability is traced. Within the framework of a Zolotarev–Dubinin dual dispersive model, an analytical equation is obtained that relates permeability to diffusion coefficients of water vapor in the pore volume, polymer skeleton material using such characteristics as porosity and the solubility coefficient. It is proposed to use this equation to predict the sorption properties for barrier and porous materials of complex architecture specifically in food packaging.

Reliable GaN-Based THz Gunn Diodes With Side-Contact and Field-Plate Technologies

For the first time, Gallium Nitride(GaN)-based Gunn diodes with side-contact and fieldplate technologies were fabricated and measured with reliable characteristics. A high negative differential resistance (NDR) region was characterised for the GaN Gunn effect using side-contact technology. The I-V measurement of the THz diode showed the ohmic and the Gunn effect region with high forward current of 0.65 A and high current drop of approximately 100 mA for a small ring diode width wd of 1.5µm with 600 nm effective diode height hd at a small threshold voltage of 8.5 V. This THz diode worked stable due to good passivation as protection from electro-migration and ionisation between the electrodes as well as a better heat sink to the GaN substrate and large side-contacts. The diodes can provide for this thickness a fundamental frequency in the range of 0.3 - 0.4 THz with reliable characteristics.

Phenotypes of bronchial asthma during the health resort period and personalized programs of medical rehabilitation

Bronchial asthma (BA) is a relevant social and medical problem in our country and around the world. Currently, phenotypes of the disease are distinguished. One of the original decisions in phenotypes distinguishing is the use of cluster analysis. However, the concept of BA phenotypes at the health resort period of rehabilitation has not yet been formed. To determine the BA phenotypes upon admission of patients to a health resort medical rehabilitation (HRMR) using cluster analysis and to offer personalized rehabilitation programs. 518 patients with asthma who underwent HRMR on the southern coast of Crimea were examined. Each patient received clinical, functional and laboratory examination. HRMR included correction of long-term treatment according to the severity of asthma, climate therapy, respiratory therapy, educational programs, and physiotherapeutic procedures. We applied cluster analysis in order to identify BA phenotypes. Description statistics methods were used for phenotype-cluster characterization, comparative analysis - for determination of reliable phenotypic characteristics and relation of the effectiveness of HRMR and phenotypes. A model of three phenotype-clusters was developed. The first cluster included patients with BA of moderate severity, uncontrolled course, frequent exacerbations, history of atopy, a tendency to obesity, moderately reduced external respiration function, fixed airway obstruction, high adherence to long-term therapy with medium doses of inhaled glucocorticoids (ICS) combined with long-acting β-2 agonists (LABA). Cluster 2 included patients with mild asthma, controlled or partially controlled course of the disease, with rare short exacerbations, late onset, preserved external respiration function and exercise tolerance, but low adherence to long-term therapy with medium and low doses of ICS. Cluster 3 included patients with moderate to severe BA, uncontrolled course, with early onset, frequent and prolonged exacerbations, severe symptoms, significantly reduced external respiration function with fixed obstruction, decreased exercise tolerance, but low adherence to long-term therapy (4th stage) with high doses of ICS in combination with LABA and long-acting anticholinergics. A close relationship was found between phenotypes-clusters and the achieved effects: a significant increase in the control of BA and a high efficiency of rehabilitation in patients of the 1st and especially 3rd clusters and low in the 2nd cluster. The optimal rehabilitation programs for each of the selected cluster phenotypes were determined. The cluster model developed with the help of artificial intelligence has demonstrated high prognostic value in the determination of the effectiveness and change of control over the course of asthma as a result of HRMR. Personalized HRMR programs are suggested.

Synergy of fluid sampling and subsea processing, key to maximising offshore asset recovery

The acquisition of accurate fluid samples for deepwater development is crucial for the correct evaluation of oil reserves. Samples collected from topside facilities do not represent the fluid being measured on the seabed. The injections of chemicals such as methanol and corrosion inhibitors, etc., downstream of the meter, and possible liquid separation or hold-up, are typical issues. Employing subsea multiphase flowmetre measurements in the underwater environment presents some significant challenges. Due to the fact that subsea multiphase flowmetre is not 'fit-and-forget' instrumentation hardware, changes in the inputs from the flow stream's actual properties can lead to errors in flowmetre data capture. A mechanistic model is employed, using the fluid properties that are equivalent to the flow stream being measured, to predict reliable reservoir fluid characteristics on the production flow stream. The present paper explores the synergy in successful application of fluid sampling and subsea processing to maximise offshore asset recovery. [Received: April 15, 2018; Accepted: August 27, 2018]

Stretchable HfO2-Based Resistive Switching Memory Using the Wavy Structured Design

In this letter, we report a stretchable HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based resistive switching memory device utilizing the wavy structured strategy. The fabricated Cu/HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Au device shows reliable and reversible resistive switching behaviors up to a stretching strain of 20%. After being released, the reproducible memory characteristics of the device can still be maintained. The statistical resistive switching parameters under various stretching strains in the range from 0% to 20% are counted, which exhibit a large OFF/ON resistance ratio (10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ), low operation voltage (2 V), good endurance and retention (10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> s), demonstrating the good and reliable stretchable memory characteristics. Moreover, the device-to-device distributions are carried out in these stretched states, further validating the device robustness on stretching strains. Our results show a promising approach to achieve the stretchable memory by rendering inorganic-based resistive switching devices with the wavy structure, which extends rigid and brittle memory towards future highly flexible, even stretchable data storage and computing.

The relationship of psychological, clinical and biological components in epilepsy

This study examined the relationship patterns of psychological characteristics, clinical and biological indicators, their relationship in the structure of the personality of epilepsy patients. The aim of this work was to study the ratio of biological and clinical and psychological components in the structure of a person suffering from epilepsy. Such characteristics was conducted as the type of disease seizures and duration of the disease were taken into account: simple, complex partial seizures, duration of the disease up to 30 years dominated. The verification of the diagnosis in the patients examined was carried out on the basis of clinical and neurological, psychopathological, pathopsychological, EEG examination and computer tomography data of the brain. The study of biological, clinical and psychological characteristics of epileptic patients was carried out using the method of clinical observation, psychodiagnostic method “Diagnosis of satisfaction of basic needs.” In patients with epilepsy revealed reliable multidimensional clinical and psychological characteristics of satisfaction of the main groups of needs: material needs, security needs, social (interpersonal) needs, the need for recognition, the need for self- expression.The considered characteristics are of interest to doctors, clinical psychologists and other professionals involved in preventive, therapeutic and rehabilitation measures of epilepsy patients.

Limitation of possibilities of cytological diagnosis of papillary thyroid cancer at the pre-surgery stage

A comparison of papillary cancer variants diagnosed on the basis of cytological findings of pre-surgery puncture biopsies with a histological variant of papillary cancer. The findings of two experts specializing in cytological diagnostics of thyroid nodules that diagnosed a possible variant of papillary cancer were compared with histological findings based on the study of material from surgically removed neoplasms. It was shown that the cytological examination at the pre-surgery stage has significant limitations in diagnosing the histological variant of the tumor, despite high sensitivity of method in diagnosing papillary cancer in general. The variability of results of the cytological determination of papillary cancer variant between the two experts was not so significant, it concerned small fluctuations in the frequency of the diagnosing og normal, follicular, cystic and Uortino-like variants. Based on the data of cytological method, it is not possible to establish the encapsulated variant and papillary microcarcinoma; there are limitations in the diagnosis of follicular and high tumor cell variants. Currently, the advisability of the recommendation to determine the variant of papillary cancer using the cytological method is questionable. However, this does not mean that it is necessary to stop the search for reliable cellular and molecular genetic characteristics of clinically aggressive variants of papillary cancer.

Bimodal person recognition using dorsal-vein and finger-vein images

Abstract Nowadays, human recognition with biometric characteristic have been investigated in many researchers. However, traditional biometric methods are not always robust against counterfeit and spoof attacks. The challenge of this work is to develop a bimodal biometric system, based on more reliable and robust characteristics against counterfeiting. Indeed, biometric system based on the venous network of the hand gives higher recognition rate compared to other systems. Furthermore, the fusion of two prints minimums the error rate and counterfeits. In our biometric system, the most challenging phase is the feature extraction step. For this, we propose a new feature extraction approach based on the concatenation of the pyramid of Difference of Gaussian (DoG) and Local Line Binary Patterns (LLBP) histograms (H-DoG_LLBP). To evaluate the proposed system, we opted for Support Vector Machine (SVM) and Artificial Neural Network (ANN) classifiers. The experimental study is based on the dorsal hand vein BOSPHORUS database and finger vein MMCBNU_6000 database. Our system presents an area under curve (AUC) equal to 0.99, and 0.001 mean square error (MSE) with ANN, and 0.0042 equal error rate (EER) with SVM.