This article reports the design, the breadboarding, and the validation of an ultrastable cryogenic sapphire oscillator operated in an autonomous cryocooler. The objective of this project was to demonstrate the feasibility of a frequency stability of 3x10(-15) between 1 and 1000 s for the European Space Agency deep space stations. This represents the lowest fractional frequency instability ever achieved with cryocoolers. The preliminary results presented in this paper validate the design we adopted for the sapphire resonator, the cold source, and the oscillator loop.
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http://dx.doi.org/10.1063/1.3290631 | DOI Listing |
Curr Drug Targets
January 2025
Chitkara College of Pharmacy, Chitkara University, Punjab, 140401, India.
Acne vulgaris is the 8th most commonly prevailing skin disorder worldwide. Its pervasiveness has been predominant in juveniles, especially males, during adolescence and in females during adulthood. The lifestyle and nutrition adopted have been significantly reported to impact the occurrence and frequency of acne.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Physics, University of Tehran, North Kargar Ave, Tehran 14395547, Iran.
In recent years, MAX phases and their two-dimensional counterparts, MXenes, have emerged as significant subjects of interest in the fields of science and engineering, owing to their varied geometries, compositions, and extensive range of applications. This research employs first-principles calculations to explore the geometrical structures, electronic characteristics, phonon dispersions, dynamic stability, electron-phonon coupling (EPC), and superconducting properties of 27 out-of-plane ordered double transition metal carbides, referred to as o-MAX phases, characterized by the general formula MM'AlC (where M = Nb, Mo, W and M' = Sc, Ti, Zr, Hf, V, Nb, Ta, Mo, W). We have identified 16 superconducting o-MAX phases, with four specific compounds WVAlC, WNbAlC, WTaAlC, and MoNbAlC exhibiting a critical temperature () that surpasses 10 K, representing the highest reported experimentally for MAX phases thus far.
View Article and Find Full Text PDFSci Rep
January 2025
College of Engineering and Information Technology, Aljanad University of Science and Technology, Taiz, Yemen.
Low-frequency oscillations (LFO) are inherent to large interconnected power systems. Timely detection and mitigation of these oscillations is essential to maintain reliable power system operation. This paper presents a methodology to identify and mitigate low-frequency oscillations ( forced and inter-area) using a wide area monitoring system (WAMS) based power system model utilizing phasor measurement units (PMUs).
View Article and Find Full Text PDFSci Rep
January 2025
IBM Multi Activities Co. Ltd., Khartoum, Sudan.
Load frequency control (LFC) systems in power grids face challenges in maintaining stability while managing computational complexity. This research presents an optimized approach combining model order reduction techniques with Teaching Learning-Based Optimization (TLBO) for PID controller tuning in single-area LFC systems. Three reduction methods-Routh Approximation, Balanced Truncation, and Hankel Norm Approximation-were implemented to reduce system order from 4th to 2nd order, achieving a 47.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mathematics, College of Science Al-Zulfi, Majmaah University, Al-Majmaah 11952, Saudi Arabia.
This study aims at investigating the dynamics of sexually transmitted infectious disease (STID), which is serious health concern. In so doing, the integer order STID model is progressed in to the time-delayed non-integer order STID model by introducing the Caputo fractional derivatives in place of integer order derivatives and including the delay factors in the susceptible and infectious compartments. Moreover, unique existence of the solution for the underlying model is ensured by establishing some benchmark results.
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