28,391 research outputs found
Advanced nanophotonics for gas spectroscopy
Full text linkThis thesis introduces advanced nanophotonic integrated devices aimed at improving minia-turized, cost-effective multi-gas detection and on-chip spectroscopic systems. Traditional spectroscopic techniques often require bulky optical components and multiple detectors, limiting their scalability for multi-gas sensing. The proposed integrated duplexers and tri-plexers enable switching between lasers to detect multiple gases using a single system. The work focuses on the design and optimization of broadband angled multimode interference duplexers, directional coupler-based duplexers, and cascaded directional coupler-based tri-plexers for combining spectroscopically relevant wavelengths in the near-infrared region. The target gases include ammonia, methane, and carbon dioxide. Through comprehensive simulations and experimental investigations, the proposed on-chip designs demonstrate su-perior performance compared to existing solutions and have a unique advantage in terms of smaller footprint and improved coupling efficiency. DC-based duplexer has been success-fully integrated with laser and GRIN lens components, resulting in a ready-to-use module for multi-gas sensing applications.
A semi-integrated photonic sensing system is presented, exploiting on-chip waveguides with Quartz Enhanced Photoacoustic spectroscopy and Light induced thermoelastic spec-troscopy (LITES). Side-polished optical fibers are explored to enhance light-matter interac-tion path when detecting water vapor and methane gases using LITES method. To further improve integration of integrated nanophotonic devices with spectroscopic devices and to enhance light-matter interaction, a novel wave confinement approach is introduced using high-contrast grating hollow core waveguides. These waveguides feature a reflective sur-face that maintains high transmission while allowing gas flow through the sidewalls, mak-ing them particularly suitable for gas spectroscopic applications. They are specifically op-timized for methane sensing at a wavelength of 3.27 μm. The final goal of this thesis is to develop a complete system that integrates a multiplexer with integrated lasers and high-efficiency interaction pathways, such as hollow core waveguides, into a spectroscopic de-vice. This compact and integration-friendly design holds great promises for enabling the development of portable, high-precision, and real-time multi-gas sensing devices for appli-cations from industrial, agricultural to environmental monitoring
Slow light to reduce the energy dissipation of Mach-Zehnder modulators in silicon photonics
No full textIntegrated Mach-Zehnder (MZ) modulators are important components in silicon photonic devices that rely on a reverse-biased p-n junction to modulate the optical signal via a change of the waveguide refractive index. Reducing their energy consumption is a crucial step towards the application of silicon photonics, especially in connection with the growing traffic volumes in data centers. In this work, we combine band-edge slow light structures consisting of silicon grating waveguides with periodic (interlaced) p-n junctions to maximize spatial matching between the optical field mode and the depletion region of the p-n junction. The two effects together will result in an improved modulation efficiency, leading to a strongly reduced energy dissipation per bit
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
Full text linkThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Letter from J. R. Eakin to Arthur G. Ringland
No full textLetter (copy) from J. R. Eakin to Arthur C. Ringland about the alignment of 40 acres near the Buggeln ranch
Evolution of the G+C content frontier in the rat cytomegalovirus genome
Full text linkWithin the 230138 bp of the rat cytomegalovirus (RCMV) genome, the G+C content changes abruptly at position 142644, constituting a G+C content frontier. To the left of this point, overall G+C content is 69.2%, and to the right it is only 47.6%. A region of extremely low G+C content (33.8%) is found in the 5 kb immediately to the right of the frontier, in which there are no predicted coding sequences. To the right of position 147501, the G+C content rises and predicted coding sequences reappear. However, these genes are much shorter (average 848bp, 50% G+C) than those in the left two-thirds of the genome (average 1462bp, 70% G+C). Whole genome alignment of several viruses indicates that the initial ultra-low G+C region appeared in the common ancestor of the genera Cytomegalovirus and Muromegalovirus, and that the lowering of G+C in the right third has been a subsequent process in the lineage leading to RCMV. The left two-thirds of RCMV has stop codon occurrences at 67.5% of their expected level, based on a modified Markov chain model of stop codon distribution, and the corresponding figure for the right third is 78%. Therefore, despite heavy mutation pressure, selective constraint has operated in the right third of the RCMV genome to maintain a degree of gene length unusual for such low G+C sequences
Correction to: Bican, R., Christensen, C., Fallieras, K., Sagester, G., O’Rourke, S., Byars, M., & Tanner, K. (2021). Rapid Implementation of Telerehabilitation for Pediatric Patients During COVID-19
Full text linkCorrection to: Bican, R., Christensen, C., Fallieras, K., Sagester, G., O’Rourke, S., Byars, M., & Tanner, K. (2021). Rapid Implementation of Telerehabilitation for Pediatric Patients During COVID-19. International Journal of Telerehabilitation, 13(1). https://doi.org/10.5195/ijt.2021.6371
The affiliation for each author was incorrectly stated as: Physical Medicine & Rehabilitation, Children’s Minnesota, Minneapolis, Minnesota, USA
The correct affiliation for each author is: Clinical Therapies, Nationwide Children’s Hospital, Columbus, Ohio, USA
The metadata for the original article has been corrected
Spherically symmetric solution of f(R,G) gravity at low energy
No full textThe weak-field and slow-motion limit of f(R,G) gravity is developed up to (v/c)(4) order in a spherically symmetric background. Considering the Taylor expansion of a general function f around vanishing values of R and G, we present general vacuum solutions up to (v/c)(4) order for the gravitational field generated by a ball-like source. The spatial behaviors at (v/c)(2) order are the same for f(R,G) gravity and f(R) gravity, and their corresponding real valued static behaviors are presented and compared with the one in general relativity. The static Yukawa-like behavior is proved to be compatible with the previous result of the most general fourth-order theory. At (v/c)(4) order, the static corrections to the Yukawa-like behavior for f(R,G) gravity, f(R) gravity, and the Starobinsky gravity are presented and compared with the one in general relativity.National Natural Science Foundation of China [11120101004, 11475006]SCI(E)[email protected]; [email protected]
The history of plant and soil nematology in Australia and New Zealand, with particular reference to the contributions of six pioneering nematologists
No full textThe history of plant and soil nematology in Australia and New Zealand, with particular reference to the contributions of six pioneering nematologists G. R. Stirling A , E , G. W. Yeates B , K. Davies C and M. Hodda D A Biological Crop Protection Pty Ltd, 3601 Moggill Road, Moggill, Qld 4072, Australia. B Landcare Research, Private Bag 11052, Palmerston North 4442, New Zealand. C Plant and Food Science, Waite Campus, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia. D CSIRO Entomology, GPO Box 1700, Canberra, ACT 2601, Australia. E Corresponding author. Email: [email protected] Abstract In an era of rapid technological advancement, it is easy to overlook those who established the knowledge base that underpins today’s research programs. This paper traces the history of plant and soil nematology in Australia and New Zealand and recognises six pioneers who contributed significantly to its development, namely N. A. Cobb, R. C. Colbran, H. R. Wallace, A. F. Bird, J. M. Fisher and W. C. Clark. Collectively, these scientists described many unique and economically important nematodes, advanced our understanding of the biology and ecology of both plant-parasitic and free-living species, laid the foundation for many of the nematode control measures that are in use today and also contributed to the development of the discipline of nematology at an international level.G. R. Stirling, G. W. Yeates, K. Davies and M. Hodd
Author Correction: A corridor of exposed ice-rich bedrock across Titan’s tropical region (Nature Astronomy, (2019), 3, 7, (642-648), 10.1038/s41550-019-0756-5)
No full textIn the version of this Article originally published, the author Rosaly Lopes was mistakenly affiliated with Northern Arizona University. Her affiliation has now been corrected to: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. © 2019, Springer Nature Limited
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