CMOS-MEMS resonators, which are promising building blocks for achieving monolithic integration of MEMS structure, can be used for timing and filtering applications, and control circuitry. SiO2 has been used to make MEMS resonators with quality factor Q > 10(4), but temperature instability remains a major challenge. In this paper, a design that uses an embedded metal block for temperature compensation is proposed and shows sub-ppm temperature stability (-0.21 ppm/K). A comprehensive analytical model is derived and applied to analyze and optimize the temperature coefficient of frequency (TCF) of the CMOS-MEMS composite material resonator. Comparison with finite element method simulation demonstrates good accuracy. The model can also be applied to predict and analyze the TCF of MEMS resonators with arbitrary mode shape, and its integration with simulation packages enables interactive and efficient design process.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1109/TUFFC.2014.006724 | DOI Listing |
Mater Horiz
January 2025
College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China.
To address the demands of rapidly advancing precision instruments requiring higher efficiency and miniaturization, permanent magnets must exhibit exceptional energy density, temperature stability, high magnetic energy product [()], and adequate coercivity (). Herein, we design rare earth Er-based magnets (2 : 17-type Er-magnets) with a composition of (Er, Sm)(Co, Fe, Cu, Zr). Erbium-based compounds (ErCo) offer a unique combination of temperature compensation and high saturation magnetization compared to other heavy rare earth elements, resulting in 2 : 17-type Er-magnets with superior temperature stability in and ().
View Article and Find Full Text PDFJ Biomed Opt
January 2025
Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States.
Significance: Accurate values of skin optical properties are essential for developing reliable computational models and optimizing optical imaging systems. However, published values show a large variability due to a variety of factors, including differences in sample collection, preparation, experimental methodology, and analysis.
Aim: We aim to explore the influence of storage conditions on the optical properties of the excised skin from 400 to 1100 nm.
R Soc Open Sci
January 2025
Sustainable Soils and Crops, Rothamsted Research, Harpenden AL5 2JQ, UK.
Seed germination is a crucial stage in plant development, intricately regulated by various environmental stimuli. Understanding these interactions is essential for optimizing planting and seedling management but remains challenging due to the trade-off effects of environmental factors on the germination process. We proposed a new conceptual model by viewing seed germination as a dynamic process in a physiological dimension, with the influence of environmental factors and seed heterogeneity characterized by a germination speed and a dispersion coefficient.
View Article and Find Full Text PDFSe Pu
February 2025
Key Laboratory of Beijing on Regional Air Pollution Control, Beijing University of Technology, Beijing 100214, China.
A comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS) method was developed to analyze 25 traditional phthalate esters (PAEs) and 19 novel alternatives in indoor dust samples. PAEs are ubiquitous in indoor environments because they are widely used as plasticizers in a variety of consumer products, and potential health concerns have prompted the need for effective monitoring methods. In this study, dust samples were collected from various indoor settings in a university campus, including classrooms, cafeterias, laboratories, and dormitories, and were subsequently ultrasonically extracted with hexane-dichloromethane (1∶1, v/v) solution for 30 min.
View Article and Find Full Text PDFSe Pu
February 2025
Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Shanghai 200237, China.
Thromboxane A (TXA), a prothrombotic factor that induces platelet aggregation and thrombosis, acts as a vasoconstrictor by activating TXA receptors (TP receptors). TXA is extremely unstable and metabolizes into three major metabolites: 2,3-dinor thromboxane B (2,3-dinor-TXB), 11-dehydro TXB(11-dh-TXB), and 11-dehydro-2,3-dinor TXB(11-dh-2,3-dinor-TXB). 8-Iso-prostaglandin F(8-iso-PGF), a prostaglandin-like compound widely considered the best biomarker of oxidative stress, can also activate TP receptors.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!