Model modification and feature study of Duffing oscillator

With the development of chaos theory, Duffing oscillator has been extensively studied in many fields, especially in electronic signal processing. As a nonlinear oscillator, Duffing oscillator is more complicated in terms of equations or circuit analysis. In order to facilitate the analysis of its characteristics, the study analyzes the circuit from the perspective of vibrational science and energetics. The classic Holmes-Duffing model is first modified to make it more popular and concise, and then the model feasibility is confirmed by a series of rigorous derivations. According to experiments, the influence of driving force amplitude, frequency, and initial value on the system is finally explained by the basic theories of physics. Through this work, people can understand the mechanisms and characteristics of Duffing oscillator more intuitively and comprehensively. It provides a new idea for the study of Duffing oscillators and more.

OPTOELECTRONIC DEVICE FOR MEASURING THE POWER OF LASER RADIATION

A device for measuring the power of the laser radiation.has been designed. The device consists of transmitter and receiving part. The transmitter includes optical radiation source and optical system for collimation of radiation. The receiver part consists of silicon photodiodes, electronic signal processing unit and unit for measurements.

BCl3 Adsorption on Pristine, S-Doped, and Cr-Doped Graphynes: A DFT Study

The adsorption of boron trichloride (BCl3) was explored onto pristine, S-doped, and Cr-doped graphyne through density functional theory computations. The interaction of BCl3 with pristine graphyne was weak and, thus, this sheet cannot be used as a sensor. Although S-doping strengthens the interaction, the S-doped sheet cannot still be used as a sensor. However, the reactivity and sensitivity of the sheet are significantly increased toward BCl3 by replacing the C atom of graphyne with the transition metal Cr. The HOMO-LUMO gap of Cr-doped graphyne reduces from 2.18 to 1.38 eV following the adsorption of BCl3, which significantly increases the electrical conductivity. Thus, the great change in the conductivity can be converted into an electronic signal, indicating that Cr-doped graphyne may be a promising sensor for BCl3. Also, its work function is considerably decreased by the adsorption process, indicating that it can also work as a work function-type sensor for BCl3 detection.

Anti-Fog Imaging and Ship Positioning and Berthing Method Based on Solar-Blind Ultraviolet Optical Electronic Signal

The foggy environment, particularly in the dense fog, would significantly weaken the general optical imaging capability. In such condition, common optical imaging methods could hardly recognize targets and self-position in an effective manner, severely impacting ship berthing operation. Targeted at ship berthing in foggy days and based on zero background interference of solar-blind ultraviolet (UV) optical electronic signal, calibration and imaging positioning method based on solar-blind UV imagers were studied here, achieving three-dimension positioning with high precision. Direct imaging and accurate positioning for assisting in ship berthing could be realized at the same time. In this article, local positioning effect in the foggy environment was evaluated by applying solar-blind UV imaging band. The measurement results verify that accurate positioning could be achieved in the foggy environment by solar-blind UV anti-fog imaging positioning approach to satisfy demands of ship berthing in foggy days.

Evolution of ERS Equipment of the MSU-MR Series as Related to Increasing the Accuracy of Radiometric Measurements and Expanding Performance Capabilities

This work is devoted to the description of the technical evolution of the MSU-MR equipment installed on Meteor-3M series spacecraft. After the launch of each successive spacecraft of the series, the development team generates new ideas concerning the modernization of the MSU-MR equipment in order to improve its metrological characteristics. This work describes in detail both the improvements of the MSU-MR equipment already tested during flight tests (expansion of the temperature measurement range, remote adjustment of the parameters of electronic signal generation paths and of the temperatures of black body simulators, refinement of the method of laboratory focusing) and of the equipment yet to be subject to flight tests (remote focusing, increasing the cooling capacity of the radiator of the black body simulator, as well as a number of others).

The Voice

Voice and singing are fundamental to music. Scales and content reflect our personal culture. Something beautiful and inspiring to one person may be a boring cacophony to another. Viewing musical evolution from the perspective of culture is therefore varied and individual. Input from science is generally less obvious, except for changes generated from acoustics of buildings, broadcasting, and electronic sound equipment. Medical studies reveal how we form sounds and tone quality, and modern electronic signal processing shows the complexity of the harmonic content of singing. The changes between sweetness, harshness, carrying power, and so on, all depend on not just volume, but the fundamental note and its harmonics, plus all the other frequencies generated in our vocalization. One fundamental may have 50 or more other frequencies. This signal processing tool is invaluable for understanding voice production.

Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES)

Charge density and molecular coverage on the surface of electrode play major roles in the science and technology of surface chemistry and biochemical sensing. However, there has been no easy and direct method to characterize these quantities. By extending the method of Transient Induced Molecular Electronic Signal (TIMES) which we have used to measure molecular interactions, we are able to quantify the amount of charge in the double layers at the solution/electrode interface for different buffer strengths, buffer types, and pH values. Most uniquely, such capabilities can be applied to study surface coverage of immobilized molecules. As an example, we have measured the surface coverage for thiol-modified single-strand deoxyribonucleic acid (ssDNA) as anchored probe and 6-Mercapto-1-hexanol (MCH) as blocking agent on the platinum surface. Through these experiments, we demonstrate that TIMES offers a simple and accurate method to quantify surface charge and coverage of molecules on a metal surface, as an enabling tool for studies of surface properties and surface functionalization for biochemical sensing and reactions.

Migrazioni. Il videotape d’artista: dall’archivio analogico all’archivio digitale

The process of obsolescence of recording and reproduction technologies, and the oblivion of the resulting works, do not define the only perspective from which we witness the risk of “cancellation” of the artist's videotapes, witnesses to the origins of the “video art” in the late 60s and early 70s. In other words, the fragility and the instability of the analog support exposed to physical-chemical and mechanical alterations (ie the irreversible wear of the magnetic tape which, passing through the readers’ heads, degrades the electronic signal and progressively “erases” the inscribed works in this support) they do not constitute, in fact, the only evidence of the risk of dissolution affecting the cultural history of this type of works. In the choice of the computer applications of which they are the object - with respect to the processes of migration from analogue to digital, of active conservation and restoration - a peculiar logic of “cancellation” acts here that we intend to investigate.