Comprehensive study on unipolar RRAM charge conduction and stochastic features, a simulation approach

An in-depth analysis of resistive switching (RS) in unipolar devices is performed by means of a new simulator based on resistive circuit breakers of different features. The forming, set and reset processes are described in terms of the stochastic formation and rupture of conductive filaments of several branches in the dielectric. Both, the electric field and temperature dependencies are incorporated in the simulation. The simulation tool was tuned with experimental data of devices fabricated making use of the Ti/HfO2/Si stack. The variability and the stochastic behavior are characterized and reproduced correctly by simulation to understand the physics behind RS. Reset curves with several current steps are explained considering the rupture of different branches of the conductive filament. The simulation approach allows to connect in a natural manner to compact modeling solutions for the devices under study.

New Method for Adjusting Coefficients PI Conroller in the Load Control System of the Shearer

The paper proposes a method using extrapolator models to predict the parameters of the PI controller. With a sudden change in the resistance of coal to cutting, in particular, at different levels of steps and their combinations, the speed of the cutting current controller and current steps also differ, the quieting time of the transient process also occurs in different times. To implement the adjustment of the coefficients of the PI controller, a feed forward artificial neural network is used, which acts as an operational means of recognizing a multidimensional response curve in the control loop. Neural networks of two architectures were used: with a scalar and vector output function. The recognition result is the estimated level of the step in the coal’s resistance to cutting based on the initial counts of the multidimensional response curve at the specified coefficients of the PI controller. The approach proposed in the article can be used in solving other applied problems in which the control object is nonlinear and the control algorithm needs to adapt to the changing unobservable effect on the object.

Stability Analysis of Slope Based on Limit Equilibrium Method and Strength Reduction Method

Drawing on the theories of limit equilibrium and finite-element strength reduction, this paper explores the instability modes and stability change laws of the slope in zones E, W, and S of Jiajika spodumene mine, through rock mechanics tests, field survey, and numerical simulation. The results show that the sliding mode of the slope is circular arc sliding or circular arc + plane sliding. Overall, the final slope of the open-pit mine is generally stable under the current design, and the slope of the current steps is reasonable.

Pathophysiological Ionotropic Glutamate Signalling in Neuroinflammatory Disease as a Therapeutic Target

Glutamate signalling is an essential aspect of neuronal communication involving many different glutamate receptors, and underlies the processes of memory, learning and synaptic plasticity. Despite neuroinflammatory diseases covering a range of maladies with very different biological causes and pathophysiologies, a central role for dysfunctional glutamate signalling is becoming apparent. This is not just restricted to the well-described role of glutamate in mediating neurodegeneration, but also includes a myriad of other influences that glutamate can exert on the vasculature, as well as immune cell and glial regulation, reflecting the ability of neurons to communicate with these compartments in order to couple their activity with neuronal requirements. Here, we discuss the role of pathophysiological glutamate signalling in neuroinflammatory disease, using both multiple sclerosis and Alzheimer’s disease as examples, and how current steps are being made to harness our growing understanding of these processes in the development of neuroprotective strategies. This review focuses in particular on N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methylisooxazol-4-yl) propionate (AMPA) type ionotropic glutamate receptors, although metabotropic, G-protein-coupled glutamate receptors may also contribute to neuroinflammatory processes. Given the indispensable roles of glutamate-gated ion channels in synaptic communication, means of pharmacologically distinguishing between physiological and pathophysiological actions of glutamate will be discussed that allow deleterious signalling to be inhibited whilst minimising the disturbance of essential neuronal function.

A 0.18-ns Response Time Digital LDO Regulator with Adaptive PI Controller in 180-nm CMOS

Digital low drop-out regulator (D-LDO) with fast settling time and superior transient response is gaining increasing attention to make up for the deficiency of analog LDO. However, as the traditional digital LDOs regulate the output voltage code at a rate of 1 bit per clock cycle, the transient response speed is limited. In this paper, a multi-bit conversion technique is proposed to improve the transient response speed. The multi-bit conversion technique is achieved by an error detector with adaptive regulation of proportion and integration parameters in the digital controller before pass devices. Besides, a voltage sensor and a time-to-digital converter are employed to convert the output voltage to digital codes. Implemented in a 180-nm CMOS process, the proposed D-LDO features under 36/33 mV of undershoot/overshoot at VOUT = 0.95 V as the load current steps up with 40 mA/1 ns on a 0.5 nF load capacitor. The simulated response time is 0.18-ns, the figure-of-merit of speed FOM1 is 0.65 ps and FOM2 achieves 0.068 pF.

Digitalization of Czech Republic Administration and its Effects not Only on Tax Administration

Recently, digitalization has been a frequently used word in various economic fields. We have been able to realize this lately mainly due to the problematic situation brought by the COVID-19 pandemic. People could not personally visit public authorities, banks, the post offices or other institutions and in many cases, it was possible for them to manage their necessary matters. It is quite clear, that Czech public authorities are not 100 % ready to be able to function fully online. However, the Czech Republic is not lax about this and it is preparing further steps to achieve online functioning. The selected current steps of the Czech Republic will be presented in this article. The hypothesis set in the article is that the current status of digitalization of administration in Czech Republic is currently insufficient.