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1
Andronov, A. A., A. V. Ikonnikov, K. V. Maremianin, V. I. Pozdnjakova, Y. N. Nozdrin, A. A. Marmalyuk, A. A. Padalitsa et al. "THz stimulated emission from simple superlattice in positive differential conductivity region". Физика и техника полупроводников 52, n. 4 (2018): 463. http://dx.doi.org/10.21883/ftp.2018.04.45812.01.
Testo completoAbstract (sommario):
AbstractNarrow band emissions at 2.6–2.8 THz are observed out of liquid helium cooled 1 mm disk chips prepared of a wafer with the very low n type doped weak barrier GaAs–GaAlAs superlattice of 1000 periods. The emissions are at about 8.0–18.0 V pulsed voltage applied to the chips in region of the chips positive DC differential conductivity that guaranties absence of inhomogeneous electric field domains in the chips. The emission frequency bands are estimated with a cyclotron resonance filter; the measurements show that the band width is of about that of the THz quantum cascade laser. By using long voltage pulses the chip heating above 100 K is achieved without substantial change in emission power. We speculate that the emission is super luminescence (amplification) of whispering gallery modes in the chips as a result of inverted Wannier-Stark level transitions under bias. The results are the first world demonstration of THz stimulated emission in a simple superlattice within region of positive DC differential conductivity; they give strong impetus for development of THz and higher frequency sources based on such simple superlattices; the sources should well compete with the THz quantum cascade lasers in particular at elevated temperatures.
2
Wang, Maorong, Yifan Zhang, Leilei Guo, Mengqi Lv, Peng Wang e Xia Wang. "Spintronics Based Terahertz Sources". Crystals 12, n. 11 (18 novembre 2022): 1661. http://dx.doi.org/10.3390/cryst12111661.
Testo completoAbstract (sommario):
Terahertz (THz) sources, covering a range from about 0.1 to 10 THz, are key devices for applying terahertz technology. Spintronics-based THz sources, with the advantages of low cost, ultra-broadband, high efficiency, and tunable polarization, have attracted a great deal of attention recently. This paper reviews the emission mechanism, experimental implementation, performance optimization, manipulation, and applications of spintronic THz sources. The recent advances and existing problems in spintronic THz sources are fully present and discussed. This review is expected to be an introduction of spintronic terahertz sources for novices in this field, as well as a comprehensive reference for experienced researchers.
3
Hu, Qing. "Generation of Terahertz Emission Based on Intersubband Transitions". International Journal of High Speed Electronics and Systems 12, n. 04 (dicembre 2002): 995–1024. http://dx.doi.org/10.1142/s0129156402001897.
Testo completoAbstract (sommario):
In this chapter, we present our work on the development of coherent THz sources based on intersubband transition in quantum-well structures. The main focus is on electrically pumped or quantum-cascade structures, which have been quite successful in generating coherent radiation at mid-infrared frequencies. Relevant issues, such as various depopulation intersubband scattering rates, the role of complex phonon spectra, and coherent vs. incoherent tunneling are discussed in details. Optically pumped sources, including optical parametric amplifiers, and both intersubband and interband pumped THz emitters, are also investigated for their feasibility in generating coherent THz radiations.
4
Wang, Suyun. "Terahertz Emission Modeling of Lunar Regolith". Remote Sensing 16, n. 21 (30 ottobre 2024): 4037. http://dx.doi.org/10.3390/rs16214037.
Testo completoAbstract (sommario):
We investigate the terahertz (THz) scattering and emission properties of lunar regolith by modeling it as a random medium with rough top and bottom boundaries and a host medium situated beneath. The total scattering and emission arise from three sources: the rough boundaries, the volume, and the interactions between the boundaries and the volume. To account for these sources, we model their respective phase matrices and apply the matrix doubling approach to couple these phase matrices to compute the total emission. The model is then used to explore insights into lunar regolith scattering and emission processes. The simulations reveal that surface roughness is the primary contributor to total scattering, while dielectric contrasts between the volume and the boundaries dominate total emission. The THz emissivity is highly sensitive to the regolith dielectric constant, particularly its imaginary part, making it a promising alternative for identifying previously undetected water ice in the lunar polar regions. The THz emissivity model developed in this study can be readily applied to invert the surface parameters of lunar regolith using THz observations.
5
Minkevičius, Linas, Liang Qi, Agnieszka Siemion, Domas Jokubauskis, Aleksander Sešek, Andrej Švigelj, Janez Trontelj, Dalius Seliuta, Irmantas Kašalynas e Gintaras Valušis. "Titanium-Based Microbolometers: Control of Spatial Profile of Terahertz Emission in Weak Power Sources". Applied Sciences 10, n. 10 (14 maggio 2020): 3400. http://dx.doi.org/10.3390/app10103400.
Testo completoAbstract (sommario):
Terahertz (THz) imaging and spectroscopy set-ups require fine optical alignment or precise control of spatial mode profile. We demonstrate universal, convenient and easy-to-use imaging—resonant and broadband antenna coupled ultrasensitive titanium-based—dedicated to accurately adjust and control spatial mode profiles without additional focusing optical components of weak power THz sources. Versatile operation of the devices is shown using different kinds of THz—electronic multiplier sources, optical THz mixer-based frequency domain and femtosecond optoelectronic THz time-domain spectrometers as well as optically pumped molecular THz laser. Features of the microbolometers within 0.15–0.6 THz range are exposed and discussed, their ability to detect spatial mode profiles beyond the antennas resonances, up to 2.52 THz, are explored. Polarization-sensitive mode control possibilities are examined in details. The suitability of the resonant antenna-coupled microbolometers to resolve low-absorbing objects at 0.3 THz is revealed via direct, dark field and phase contrast imaging techniques as well.
6
Chen, Yuxuan, Yuhang He, Liyuan Liu, Zhen Tian, Jianming Dai e Xi-Cheng Zhang. "Backward THz Emission from Two-Color Laser Field-Induced Air Plasma Filament". Sensors 23, n. 10 (10 maggio 2023): 4630. http://dx.doi.org/10.3390/s23104630.
Testo completoAbstract (sommario):
Two-color laser field-induced plasma filaments are efficient broadband terahertz (THz) sources with intense THz waves emitted mainly in the forward direction, and they have been investigated intensively. However, investigations on the backward emission from such THz sources are rather rare. In this paper, we theoretically and experimentally investigate the backward THz wave radiation from a two-color laser field-induced plasma filament. In theory, a linear dipole array model predicts that the proportion of the backward emitted THz wave decreases with the length of the plasma filament. In our experiment, we obtain the typical waveform and spectrum of the backward THz radiation from a plasma with a length of about 5 mm. The dependence of the peak THz electric field on the pump laser pulse energy indicates that the THz generation processes of the forward and backward THz waves are essentially the same. As the laser pulse energy changes, there is a peak timing shift in the THz waveform, implying a plasma position change caused by the nonlinear-focusing effect. Our demonstration may find applications in THz imaging and remote sensing. This work also contributes to a better understanding of the THz emission process from two-color laser-induced plasma filaments.
7
Huang, Hsin-hui, Takeshi Nagashima, Wei-hung Hsu, Saulius Juodkazis e Koji Hatanaka. "Dual THz Wave and X-ray Generation from a Water Film under Femtosecond Laser Excitation". Nanomaterials 8, n. 7 (13 luglio 2018): 523. http://dx.doi.org/10.3390/nano8070523.
Testo completoAbstract (sommario):
Simultaneous emission of the THz wave and hard X-ray from thin water free-flow was induced by the irradiation of tightly-focused femtosecond laser pulses (35 fs, 800 nm, 500 Hz) in air. Intensity measurements of the THz wave and X-ray were carried out at the same time with time-domain spectroscopy (TDS) based on electro-optic sampling with a ZnTe(110) crystal and a Geiger counter, respectively. Intensity profiles of the THz wave and X-ray emission as a function of the solution flow position along the incident laser axis at the laser focus show that the profile width of the THz wave is broader than that of the X-ray. Furthermore, the profiles of the THz wave measured in reflection and transmission directions show different features and indicate that THz wave emission is, under single-pulse excitation, induced mainly in laser-induced plasma on the water flow surface. Under double-pulse excitation with a time separation of 4.6 ns, 5–10 times enhancements of THz wave emission were observed. Such dual light sources can be used to characterise materials, as well as to reveal the sequence of material modifications under intense laser pulses.
8
Hawecker, J., E. Rongione, A. Markou, S. Krishnia, F. Godel, S. Collin, R. Lebrun et al. "Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers". Applied Physics Letters 120, n. 12 (21 marzo 2022): 122406. http://dx.doi.org/10.1063/5.0079955.
Testo completoAbstract (sommario):
Spintronic terahertz (THz) emitters based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse generation. The design, materials, and control of these interfaces at the nanometer level have become vital to engineer their THz emission properties. In this work, we present studies of the optimization of such structures through a multi-pronged approach, taking advantage of material and interface engineering to enhance THz spintronic emission. This includes the application of multi-stacks of HM/FM junctions and their application to trilayer structures, the use of spin-sinks to simultaneously enhance the THz emitted fields and reduce the use of thick Pt layers to reduce optical absorption, and the use of semi-metals to increase the spin polarization and, thus, THz emission. Through these approaches, significant enhancements of the THz field can be achieved. Importantly, taking into account the optical absorption permits to elucidate novel phenomena such as the relation between the spin diffusion length and the spin-sink using THz spectroscopy, as well as possibly distinguishing between self- and interface-spin-to-charge conversion in semi-metals.
9
Lange, Simon Jappe, Matthias C. Hoffmann e Peter Uhd Jepsen. "Lightwave-driven electron emission for polarity-sensitive terahertz beam profiling". APL Photonics 8, n. 1 (1 gennaio 2023): 016105. http://dx.doi.org/10.1063/5.0125947.
Testo completoAbstract (sommario):
The full exploitation of advanced light sources in the terahertz (THz) frequency range requires versatile experimental tools to fully characterize the spatial, temporal, and spectral shapes of the THz electric field. Several techniques for passive THz beam profiling exist that offer information about the temporally integrated intensity. Thus, any information about the electric field itself is lost. Here, we show that a UV–visible light emission produced via a lightwave-driven field emission from single-layer metasurfaces can be used to visualize the peak electric field distribution of THz beams in real time. Our technique is scalable up to frequencies approaching the plasma frequency of the metal used for the metasurface. Uniquely, our device is sensitive to the absolute polarity of the THz lightwave. These findings demonstrate a general pathway to designing metamaterial-based field-sensitive optical detectors suitable for the entire THz and IR spectral region.
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Consolino, Luigi, Malik Nafa, Michele De Regis, Francesco Cappelli, Saverio Bartalini, Akio Ito, Masahiro Hitaka et al. "Direct Observation of Terahertz Frequency Comb Generation in Difference-Frequency Quantum Cascade Lasers". Applied Sciences 11, n. 4 (4 febbraio 2021): 1416. http://dx.doi.org/10.3390/app11041416.
Testo completoAbstract (sommario):
Terahertz quantum cascade laser sources based on intra-cavity difference frequency generation from mid-IR devices are an important asset for applications in rotational molecular spectroscopy and sensing, being the only electrically pumped device able to operate in the 0.6–6 THz range without the need of bulky and expensive liquid helium cooling. Here we present comb operation obtained by intra-cavity mixing of a distributed feedback laser at λ = 6.5 μm and a Fabry–Pérot device at around λ = 6.9 μm. The resulting ultra-broadband THz emission extends from 1.8 to 3.3 THz, with a total output power of 8 μW at 78 K. The THz emission has been characterized by multi-heterodyne detection with a primary frequency standard referenced THz comb, obtained by optical rectification of near infrared pulses. The down-converted beatnotes, simultaneously acquired, confirm an equally spaced THz emission down to 1 MHz accuracy. In the future, this setup can be used for Fourier transform based evaluation of the phase relation among the emitted THz modes, paving the way to room-temperature, compact, and field-deployable metrological grade THz frequency combs.
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Fujita, Kazuue, Seungyong Jung, Yifan Jiang, Jae Hyun Kim, Atsushi Nakanishi, Akio Ito, Masahiro Hitaka, Tadataka Edamura e Mikhail A. Belkin. "Recent progress in terahertz difference-frequency quantum cascade laser sources". Nanophotonics 7, n. 11 (27 settembre 2018): 1795–817. http://dx.doi.org/10.1515/nanoph-2018-0093.
Testo completoAbstract (sommario):
AbstractTerahertz quantum cascade laser (QCL) sources based on intra-cavity difference frequency generation are currently the only electrically pumped monolithic semiconductor light sources operating at room temperature in the 1–6-THz spectral range. Relying on the active regions with the giant second-order nonlinear susceptibility and the Cherenkov phase-matching scheme, these devices demonstrated drastic improvements in performance in the past several years and can now produce narrow-linewidth single-mode terahertz emission that is tunable from 1 to 6 THz with power output sufficient for imaging and spectroscopic applications. This paper reviews the progress of this technology. Recent efforts in wave function engineering using a new active region design based on a dual-upper-state concept led to a significant enhancement of the optical nonlinearity of the active region for efficient terahertz generation. The transfer of Cherenkov devices from their native semi-insulating InP substrates to high-resistivity silicon substrates resulted in a dramatic improvement in the outcoupling efficiency of terahertz radiation. Cherenkov terahertz QCL sources based on the dual-upper-state design have also been shown to exhibit ultra-broadband comb-like terahertz emission spectra with more than one octave of terahertz frequency span. The broadband terahertz QCL sources operating in continuous-wave mode produces the narrow inter-mode beat-note linewidth of 287 Hz, which indicates frequency comb operation of mid-infrared pumps and thus supports potential terahertz comb operation. Finally, we report the high-quality terahertz imaging obtained by a THz imaging system using terahertz QCL sources based on intra-cavity difference frequency generation.
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Rakesh Kumar, V., Kamalesh Jana, Indranuj Dey, K. Chandra Vardhan, Amit D. Lad, Jeffrey M. Brown, Mette B. Gaarde, Arnaud Couairon e G. Ravindra Kumar. "Spectral and intensity control of high energy terahertz radiation from bulk liquids". Journal of Physics D: Applied Physics 55, n. 9 (23 novembre 2021): 095107. http://dx.doi.org/10.1088/1361-6463/ac3455.
Testo completoAbstract (sommario):
Abstract High power, broadband terahertz (THz) radiation from liquids, excited by intense, femtosecond 800 nm laser pulses has been demonstrated recently, overturning the long held belief that liquids would not give such emission due to their absorption in the THz region. Given the widespread interest in the use of THz radiation for several applications and the energy and bandwidth limitations of existing sources, liquids are expected to attract great attention in the future. While the emission at tens of microjoules from liquids is very promising, it is important to explore whether control of the THz flux and spectrum is achievable by manipulating the laser or liquid parameters. In this paper we present results on manipulating the spectrum of THz radiation from liquids by chirping the input laser pulse and optimizing the THz output energy by laser chirp as well as optimizing the focal position. We demonstrate tunability by varying the chirp of the laser pulse and show that the THz emission predominantly comes from the region near the end of the liquid path, consistent with the absorption of THz radiation by liquids. This control gives us an opportunity to tune the THz radiation to suit experimental needs. We present simulations that support the results.
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Abbes, Alaeddine, Annick Pénarier, Philippe Nouvel, Arnaud Garnache e Stéphane Blin. "Multipolar Photoconductive Antennas for THz Emission Driven by a Dual-Frequency Laser Based on Transverse Modes". Electronics 12, n. 22 (17 novembre 2023): 4679. http://dx.doi.org/10.3390/electronics12224679.
Testo completoAbstract (sommario):
Continuous-wave tunable photonics-based THz sources present limited output power due to the restricted input optical power accepted by photomixers, along with reduced radiation resulting from low paraxial field amplitude. Here, we investigate multipolar antenna designs to increase the available continuous-wave THz output power by incorporating more photomixers. For this purpose, the spatial structures of the optical and THz E-fields are designed to enhance THz power and radiation in the far field. Simulations of 2 to 4 dipole antennas are conducted, demonstrating an improvement in antenna gain compared to standard dipole antennas. This is in addition to a potential increase in THz power and radiation for photomixing applications. Such work also paves the way for functionalizing the spatial structure of THz light for advanced applications.
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Li, Xin Xing, Xiao Yu Zhang, Hua Qin e Bao Shun Zhang. "Design of a Cryogenic Terahertz Fourier Transform Spectrometer". Advanced Materials Research 571 (settembre 2012): 352–56. http://dx.doi.org/10.4028/www.scientific.net/amr.571.352.
Testo completoAbstract (sommario):
With the rapid development of the terahertz technique, many new devices are developed in recent years, and most of them need cryogenic environment. To evaluate the characteristics of these devices at low temperature, a cryogenic terahertz Fourier transform spectrometer system (THz-FTS) is designed and developed. With the different combinations of terahertz sources and detectors, this THz-FTS system can test the frequency response of the detectors, the emission spectrum of the sources, and the transmittance of material in the cryogenic environment at terahertz frequency range and also the basic electrical characteristics of the devices. The cryogenic THz-FTS system is designed multi-functional, low noise and compacted to test both the optical and electrical characteristics of the terahertz devices at low temperature.
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Zhang, Jinying, Bingnan Wang, Rui Wang, Jiacheng Wang, Xinye Wang e Yexiaotong Zhang. "Multiple Broadband Infrared Topological Photonic Crystal Valley States Based on Liquid Crystals". Materials 17, n. 21 (25 ottobre 2024): 5212. http://dx.doi.org/10.3390/ma17215212.
Testo completoAbstract (sommario):
Spectral tunable technology has to meet the requirements of strong robustness and wide spectral range. We propose a method for the transmission and manipulation of infrared topological photonic crystal valley states based on tunable refractive index method that exhibits broad-spectrum and multi-band characteristics, along with a tunable emission angle. With this structure, different rotational directions of vortex light sources can independently excite the K valley and K′ valley within the frequency band ranging from 75.64 THz to 99.61 THz. At frequencies from 142.60 THz to 171.12 THz, it is possible to simultaneously excite both the K valley and K′ valley. The dual refractive index tunable design allows for the adjustment of the emission angle at a fixed frequency, enabling control over the independent excitation of either a single K valley or K′ valley, as well as their simultaneous excitation. This capability has significant implications for photonic computation and tunable filtering, offering enhanced operational flexibility and expanded functionality for future optical communications and integrated optical circuits.
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Shipilo, D. E., I. A. Nikolaeva, D. V. Pushkarev, G. E. Rizaev, D. V. Mokrousova, A. V. Koribut, Ya V. Grudtsyn et al. "Balance of emission from THz sources in DC-biased and unbiased filaments in air". Optics Express 29, n. 25 (22 novembre 2021): 40687. http://dx.doi.org/10.1364/oe.442534.
Testo completo
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Novelli, Fabio, Biswajit Guchhait e Martina Havenith. "Towards Intense THz Spectroscopy on Water: Characterization of Optical Rectification by GaP, OH1, and DSTMS at OPA Wavelengths". Materials 13, n. 6 (13 marzo 2020): 1311. http://dx.doi.org/10.3390/ma13061311.
Testo completoAbstract (sommario):
Water is the most prominent solvent. The unique properties of water are rooted in the dynamical hydrogen-bonded network. While TeraHertz (THz) radiation can probe directly the collective molecular network, several open issues remain about the interpretation of these highly anharmonic, coupled bands. In order to address this problem, we need intense THz radiation able to drive the liquid into the nonlinear response regime. Firstly, in this study, we summarize the available brilliant THz sources and compare their emission properties. Secondly, we characterize the THz emission by Gallium Phosphide (GaP), 2–{3–(4–hydroxystyryl)–5,5–dimethylcyclohex–2–enylidene}malononitrile (OH1), and 4–N,N–dimethylamino–4′–N′–methyl–stilbazolium 2,4,6–trimethylbenzenesulfonate (DSTMS) crystals pumped by an amplified near-infrared (NIR) laser with tunable wavelength. We found that both OH1 as well as DSTMS could convert NIR laser radiation between 1200 and 2500 nm into THz radiation with high efficiency (> 2 × 10−4), resulting in THz peak fields exceeding 0.1 MV/cm for modest pump excitation (~ mJ/cm2). DSTMS emits the broadest spectrum, covering the entire bandwidth of our detector from ca. 0.5 to ~7 THz, also at a laser wavelength of 2100 nm. Future improvements will require handling the photothermal damage of these delicate organic crystals, and increasing the THz frequency.
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Kumar, Manoj, Teyoun Kang, Hyung Seon Song e Min Sup Hur. "Particle-in-cell simulations of THz emission from plasma by oblique collision of two-electron beams". Physics of Plasmas 29, n. 3 (marzo 2022): 033102. http://dx.doi.org/10.1063/5.0073570.
Testo completoAbstract (sommario):
We studied the THz radiation generated by a beam-plasma system using two-dimensional (2D) particle-in-cell (PIC) simulations. The Langmuir waves excited by two counterpropagating electron beams, via two-stream instability, collide with each other at an oblique angle, which forms a high beam-density modulation near the collision region, where both beam electrons become trapped. As a result, spatially localized Langmuir wave packets with large longitudinal-electric field amplitudes are formed, which give rise to bursts of electromagnetic radiation. Our 2D PIC simulations of the two thin, low-density, asymmetric, electron beams colliding obliquely show that a strong THz emission is obtained at the second harmonic of the plasma frequency (f = 1.0 THz), with a narrow spectral width (∼0.80%) in vacuum and significantly higher efficiency than the head-on-collision case. The efficiency of power conversion from electron beams to THz radiation measured in vacuum reaches around ∼0.0289, for a continuous injection of beams into the plasma, making it suitable for applications requiring high-power narrow-band THz radiation sources.
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WRABACK, MICHAEL, GRACE D. CHERN, ERIC D. READINGER, PAUL H. SHEN, GREGOR KOBLMÜLLER, CHAD GALLINAT e JAMES S. SPECK. "INDIUM NITRIDE: A NEW MATERIAL FOR HIGH EFFICIENCY, COMPACT, 1550nm LASER-BASED TERAHERTZ SOURCES IN CHEMICAL AND BIOLOGICAL DETECTION". International Journal of High Speed Electronics and Systems 18, n. 01 (marzo 2008): 3–9. http://dx.doi.org/10.1142/s0129156408005084.
Testo completoAbstract (sommario):
Indium nitride ( InN ) is identified as a promising terahertz (THz) emitter based on the optical and electronic properties of high quality In - and N -face samples. Time domain THz spectroscopy has been employed to measure the pump wavelength and background carrier concentration dependence of THz emission from InN . There is no discernable difference between the In - and N -face InN samples, as expected for the improved crystalline quality and concomitant low background electron density and high mobility for both polarities. While there is only a weak dependence of THz signal on pump wavelength from 800 nm to 1500 nm, there is a strong dependence on background electron density. Modeling shows that the dominant mechanism for THz generation in bulk InN is the current associated with the diffusion of the photo-generated electrons at elevated electron temperature (photo-Dember effect) and the redistribution of the background electrons under drift, with larger screening from the higher mobility electrons as compared to holes. Compensation or p -type doping in conjunction with manipulation of the large internal electric fields in InN/InGaN nanostructures should lead to significant improvements in THz emitters.
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Shahrir R. Kasjoo, Arun K. Singh, Claudio Balocco e Aimin Song. "Terahertz Imaging Using Nanorectifier-Based Detectors and Broadband Thermal Sources". International Journal of Nanoelectronics and Materials (IJNeaM) 16, DECEMBER (26 dicembre 2023): 143–53. http://dx.doi.org/10.58915/ijneam.v16idecember.400.
Testo completoAbstract (sommario):
Several terahertz imaging experiments have been conducted at room temperature using a self-switching diode (SSD) rectenna as a detector, and a broadband thermal source (at 610 °C) as a continuous-wave terahertz generator. Since the terahertz emission produced by the source is non-coherent with random polarizations and has a wide-ranging spectrum, the SSD-based rectenna employed in this work utilizes a planar spiral micro- antenna which has a circular polarization that able to effectively capture all incident radiation regardless of the angles. The antenna has been designed for a broadband frequency response in the range of 0.1-10 THz. This is to ensure the terahertz images produced are ascribed to the terahertz radiation collected by the antenna, but without eliminating the possibility of thermal effects at frequencies higher than the terahertz region. In order to further validate the results obtained, an Airy pattern experiment has been conducted. Based on this experiment, the effective frequency response of the SSD rectenna is estimated at 2.29 THz. The utilization of thermal source and micro-size rectenna in this work may pave the way to explore many opportunities in developing flexible, compact, and low-cost terahertz imaging systems without the use of expensive components (e.g., typically lasers are used as terahertz sources).
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Shimawaki, Hidetaka, Masayoshi Nagao e Katsuhisa Murakami. "(Invited) Photo-Assisted Electron Emission from Silicon-Based Electron Emission Devices". ECS Meeting Abstracts MA2023-02, n. 30 (22 dicembre 2023): 1533. http://dx.doi.org/10.1149/ma2023-02301533mtgabs.
Testo completoAbstract (sommario):
Ultrafast pulsed electron sources with spatial coherence have attracted significant interest in emerging applications such as scientific instruments of ultrafast electron microscopy [1-3] and electron beam lithography [4], and also as sources of X-ray [5] and micro- and THz-waves [6-9]. In particular, high-frequency electron bunch trains generated directly from the cathode surface can not only dramatically reduce dimensions and weight through the elimination of the pre-modulation circuit, but can also provide extremely high efficiency and improve the power in the electron beam devices due to coherence effects. One solution is employing photoemission from electron sources driven by ultrashort laser pulses for such emerging applications. Metallic flat photocathodes and recently metallic nanotips have been employed. However, a low quantum efficiency (QE), typically of approximately 0.01 %, and a large work function require a high-power UV laser to generate an intense electron beam. Negative electron affinity (NEA) semiconductor photocathodes such as NEA GaAs can provide QE as high as ~ 10 % [10], operating using visible laser light irradiation. However, the NEA surface is fragile and easily damaged by residual gas adsorption or beam extraction. In this presentation, we introduce the research and development of gated Si-FEAs with a volcano structure and planar-type electron emission devices based on a MOS diode structure and discuss the potential of the devices as a photocathode of the devices operating without NEA surface treatment. We investigate the optical properties of emitted electrons from the devices under visible laser light irradiation. The results indicate that Si-based electron emission devices with a fully optimized structure hold promise as a photocathode with a high QE and a high-speed response for generating a train of ultrashort electron bunches, operating without NEA surface treatment. References [1] H. Dömer, and O. Bostanjoglo, Rev. Sci. Instrum. 74, 4369 (2003). [2] W. E. King, G. H. Campbell, A. Frank, and B. Reed, J. Appl. Phys. 97, 111101 (2005). [3] K. Bücker, M. Picher, O. Crégut, T. LaGrange, B. W. Reed, S. T. Park, D. J. Masiel, and F. Banharta, Ultramicroscopy 117, 8 (2016). [4] J. E. Schneider, J. Vac. Sci. Technol. B 16, 3192 (1998). [5] X. J. Wang, X. Qiu, and I. Ben-Zvi, Phys. Rev. E 54, R3121 (1996). [6] C. A. Spindt, C. E. Holland, P. R. Schwoebel, and I. Brodie, J. Vac. Sci. Technol. B 14, 1986 (1996). [7] K. L. Jensen, R. H. Abrams, and R. K. Paker, J. Vac. Sci. Technol. B 16, 749 (1998). [8] H. Ishizuka, Y. Kawamura, K. Yokoo, H. Mimura, H. Shimawaki and A. Hosono, Nucl. Instr. Meth. Phys. Res. A 445, 276 (2000). [9] Y. Neo, H. Shimawaki, T. Matsumoto and H. Mimura, J. Vac. Sci. Technol. B 23, 840 (2005). [10] W. Liu, S. Zhang, M. Stutzman, and M. Poelker, Phys. Rev. Accel. Beams 19, 103402 (2016).
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Lerch, Ph, P. Dumas, T. Schilcher, A. Nadji, A. Luedeke, N. Hubert, L. Cassinari et al. "Assessing noise sources at synchrotron infrared ports". Journal of Synchrotron Radiation 19, n. 1 (25 novembre 2011): 1–9. http://dx.doi.org/10.1107/s0909049511041884.
Testo completoAbstract (sommario):
Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR emission in microspectroscopy, as well as the far infrared (also called THz) range for spectroscopy. Compared with a thermal (laboratory-based source), IR synchrotron radiation sources offer enhanced brilliance of about two to three orders of magnitude in the mid-IR energy range, and enhanced flux and brilliance in the far-IR energy range. Synchrotron radiation also has a unique combination of a broad wavelength band together with a well defined time structure. Thermal sources (globar, mercury filament) have excellent stability. Because the sampling rate of a typical IR Fourier-transform spectroscopy experiment is in the kHz range (depending on the bandwidth of the detector), instabilities of various origins present in synchrotron radiation sources play a crucial role. Noise recordings at two different IR ports located at the Swiss Light Source and SOLEIL (France), under conditions relevant to real experiments, are discussed. The lowest electron beam fluctuations detectable in IR spectra have been quantified and are shown to be much smaller than what is routinely recorded by beam-position monitors.
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Volkov, O. Y., I. N. Duzhikov, R. A. Khabibullin, A. N. Baranov e Y. Y. Divin. "Subterahertz difference-frequency generation in terahertz quantum cascade lasers". Applied Physics Letters 121, n. 26 (26 dicembre 2022): 263504. http://dx.doi.org/10.1063/5.0135562.
Testo completoAbstract (sommario):
We have detected subterahertz spectral lines in the emission of free-running GaAs/AlGaAs quantum cascade lasers (QCLs) operating around 3 THz. We have found that the power W( fd) of an individual sub-THz line at the frequency fd is directly proportional to a power product W( fi) × W( fk) of the corresponding pair of THz lines having the frequency difference fi − fk = fd. The established one-to-one correspondence of each sub-THz line to pair combinations of THz lines proves the nonlinear mechanism of difference-frequency generation (DFG) in the QCL active region. The conversion efficiencies W( fi − fk)/[ W( fi) × W( fk)] estimated from the experimental data are about 4 × 10−3 and 5 × 10−5 W−1 for the sub-THz lines found at 132 and 310 GHz, correspondingly. Considering nonlinear polarization of QCL active regions as the reason for DFG, we have evaluated the following values of the second-order nonlinear susceptibility χ(2)(132 GHz) ≅ 7 × 105 pm/V and χ(2)(310 GHz) ≅ 4 × 104 pm/V from the experimental data. The obtained results pave the way for the use of THz QCLs as sources of sub-THz radiation.
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Valušis, Gintaras, Alvydas Lisauskas, Hui Yuan, Wojciech Knap e Hartmut G. Roskos. "Roadmap of Terahertz Imaging 2021". Sensors 21, n. 12 (14 giugno 2021): 4092. http://dx.doi.org/10.3390/s21124092.
Testo completoAbstract (sommario):
In this roadmap article, we have focused on the most recent advances in terahertz (THz) imaging with particular attention paid to the optimization and miniaturization of the THz imaging systems. Such systems entail enhanced functionality, reduced power consumption, and increased convenience, thus being geared toward the implementation of THz imaging systems in real operational conditions. The article will touch upon the advanced solid-state-based THz imaging systems, including room temperature THz sensors and arrays, as well as their on-chip integration with diffractive THz optical components. We will cover the current-state of compact room temperature THz emission sources, both optolectronic and electrically driven; particular emphasis is attributed to the beam-forming role in THz imaging, THz holography and spatial filtering, THz nano-imaging, and computational imaging. A number of advanced THz techniques, such as light-field THz imaging, homodyne spectroscopy, and phase sensitive spectrometry, THz modulated continuous wave imaging, room temperature THz frequency combs, and passive THz imaging, as well as the use of artificial intelligence in THz data processing and optics development, will be reviewed. This roadmap presents a structured snapshot of current advances in THz imaging as of 2021 and provides an opinion on contemporary scientific and technological challenges in this field, as well as extrapolations of possible further evolution in THz imaging.
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Ushakov, Aleksandr, Pavel Chizhov, Irina Nikolaeva, Daniil Shipilo, Nikolay Panov, Vladimir Bukin, Kseniia Mamaeva, Olga Kosareva e Sergey Garnov. "Superposition of 2ω and Electrostatic Field Induced Terahertz Waveforms in DC-Biased Two-Color Filament". Applied Sciences 11, n. 24 (14 dicembre 2021): 11888. http://dx.doi.org/10.3390/app112411888.
Testo completoAbstract (sommario):
Increase in conversion efficiency from a femtosecond optical pump into broadband terahertz (THz) radiation is currently an essential issue since it boosts THz source performance for medicine and security applications. An air-plasma based THz radiation from a two-color femtosecond filament is the most efficient gas-based THz emitter, with a dipole local source having a maximum on the beam propagation axis. In this work, we show the novel advancement to THz yield increase with preservation of the forwardly directed dipole radiation. The two-color THz source can be enhanced if the filament plasma channel is placed into an external electrostatic field (DC bias), which is parallel to the second harmonic polarization direction. In the experiment, we produce a plasma channel from 800-nm, ∼50-fs, 2-mJ pulse with 200 μJ of 400-nm, ∼50-fs mixed with the pump, and allocate it between the electrodes carrying 7-kV/cm static field. Time-domain measurements and 3D+time simulations of THz waveforms from the two-color DC-biased filament show that the THz emission is the superposition of the THz waveforms generated in the 800+400-nm filament without a DC-bias and in the 800-nm (without 400-nm) plasma channel biased by 7-kV/cm static field. The additivity of the two local dipole THz sources is possible if the majority of free electrons are produced by the pump pulse.
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Moldosanov, К. А., e V. M. Lelevkin. "Method for Effective Increasing the Decomposition Rate of Ammonium Perchlorate in Solid Rocket Fuel". Bulletin of the Karaganda University "Physics Series" 11629, n. 4 (28 dicembre 2024): 74–82. https://doi.org/10.31489/2024ph4/74-82.
Testo completoAbstract (sommario):
Ammonium perchlorate (AP) is a common oxidizer in solid rocket propellants. For devices, the most im- portant parameter of which is the speed of movement, the key correlation is between the jet thrust and the combustion rate of fuels and, consequently, the rate of thermal decomposition of the AP. To increase the de- composition rate of AP, fuel, aluminum powder, is used in the form of nanoparticles. The aim of this work is to identify the decomposition mechanism of AP molecules under conditions where aluminum nanoparticles, in addition to acting as a fuel, also act as catalysts for the decomposition of AP. The result of spraying alumi- num nanoparticles into multiple nanoclusters in the fuel combustion zone due to the melting of nanoparticle cores and the destruction of aluminum oxide shells is considered. In this case, aluminum nanoclusters become sources of terahertz (THz) radiation. Since the frequencies of vibrational and rotational oscillations in AP molecules are in the THz range, irradiation of AP molecules with THz photons promotes their decomposition. It is proposed to use emission of THz photons by aluminum nanoclusters, increasing its intensity by introduc- ing 3d impurities into aluminum, which increase the density of electron states near the Fermi level of alumi- num.
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Herpin, F., A. Baudry, A. M. S. Richards, M. D. Gray, N. Schneider, K. M. Menten, F. Wyrowski, S. Bontemps, R. Simon e H. Wiesemeyer. "First detection of a THz water maser in NGC 7538-IRS1 with SOFIA and new 22 GHz e-MERLIN maps". Astronomy & Astrophysics 606 (ottobre 2017): A52. http://dx.doi.org/10.1051/0004-6361/201731056.
Testo completoAbstract (sommario):
Context. The formation of massive stars (M> 10M⊙, L > 103L⊙) is still not well understood. Accumulating a large amount of mass infalling within a single entity in spite of radiation pressure is possible if, in addition to several other conditions, enough thermal energy is released. Despite numerous water line observations over a broad range of energies obtained with the Herschel Space Observatory, observations were not able to trace the emission from the hot core around the newly forming protostellar object in most of the sources. Aims. We wish to probe the physical conditions and water abundance in the inner layers of the host protostellar object NGC 7538-IRS1 using a highly excited H2O line. Water maser models predict that several THz water masers should be detectable in these objects. We therefore aim to detect the o-H2O 82,7−73,4 line in a star forming region for the first time. Model calculations have predicted this line to show maser action. Methods. We present SOFIA observations of the o-H2O 82,7−73,4 line at 1296.41106 GHz and a 616−523 22 GHz e-MERLIN map of the region (the very first 22 GHz images made after the e-MERLIN upgrade). In order to be able to constrain the nature of the emission – thermal or maser – we used near-simultaneous observations of the 22 GHz water maser performed with the Effelsberg radiotelescope and e-MERLIN. A thermal water model using the RATRAN radiative transfer code is presented based on HIFI pointed observations. Molecular water abundances are derived for the hot core. Results. The o-H2O 82,7−73,4 line is detected toward NGC 7538-IRS1 with one feature at the source velocity (–57.7 kms-1) and another one at –48.4 kms-1. We propose that the emission at the source velocity is consistent with thermal excitation and is excited in the innermost part of the IRS1a, in the closest circumstellar environment of the massive protostellar object. The other emission is very likely the first detection of a water THz maser line, pumped by shocks due to the IRS1b outflow, in a star-forming region. Assuming thermal excitation of the THz line, the water abundance in the hot core of NGC 7538-IRS1 is estimated to be 5.2 × 10-5 with respect to H2.
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Li, Yuyu, Khwanchai Tantiwanichapan, Anna K. Swan e Roberto Paiella. "Graphene plasmonic devices for terahertz optoelectronics". Nanophotonics 9, n. 7 (14 maggio 2020): 1901–20. http://dx.doi.org/10.1515/nanoph-2020-0211.
Testo completoAbstract (sommario):
AbstractPlasmonic excitations, consisting of collective oscillations of the electron gas in a conductive film or nanostructure coupled to electromagnetic fields, play a prominent role in photonics and optoelectronics. While traditional plasmonic systems are based on noble metals, recent work has established graphene as a uniquely suited materials platform for plasmonic science and applications due to several distinctive properties. Graphene plasmonic oscillations exhibit particularly strong sub-wavelength confinement, can be tuned dynamically through the application of a gate voltage, and span a portion of the infrared spectrum (including mid-infrared and terahertz (THz) wavelengths) that is not directly accessible with noble metals. These properties have been studied in extensive theoretical and experimental work over the past decade, and more recently various device applications are also beginning to be explored. This review article is focused on graphene plasmonic nanostructures designed to address a key outstanding challenge of modern-day optoelectronics – the limited availability of practical, high-performance THz devices. Graphene plasmons can be used as a means to enhance light–matter interactions at THz wavelengths in a highly tunable fashion, particularly through the integration of graphene resonant structures with additional nanophotonic elements. This capability is ideally suited to the development of THz optical modulators (where absorption is switched on and off by tuning the plasmonic resonance) and photodetectors (relying on plasmon-enhanced intraband absorption or rectification of charge-density waves), and promising devices based on these principles have already been reported. Novel radiation mechanisms, including light emission from electrically excited graphene plasmons, are also being explored for the development of compact narrowband THz sources.
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Xu, J., F. Schreier, P. Vogt, A. Doicu e T. Trautmann. "A sensitivity study for far infrared balloon-borne limb emission sounding of stratospheric trace gases". Geoscientific Instrumentation, Methods and Data Systems Discussions 3, n. 1 (14 maggio 2013): 251–303. http://dx.doi.org/10.5194/gid-3-251-2013.
Testo completoAbstract (sommario):
Abstract. This paper presents a sensitivity study performed for trace gases retrieval from synthetic observations by TELIS (TErahertz and submillimeter LImb Sounder) which is a stratospheric balloon-borne cryogenic heterodyne spectrometer. Issues pertaining to hydroxyl radical (OH) retrieval from the far infrared measurements by the 1.8 THz channel are addressed. The study is conducted by a retrieval code PILS (Profile Inversion for Limb Sounding) developed to solve the nonlinear inverse problems arising in the analysis of infrared/microwave limb sounding measurements. PILS combines a line-by-line forward model with automatic differentiation for computing Jacobians and employs regularized nonlinear least squares inversion. We examine the application of direct and iterative regularization methods and evaluate the performance of single- and multi-profile retrievals. Sensitivities to expected errors in calibration procedure, instrumental knowledge and atmospheric profiles have been analyzed. Nonlinearity effect, inaccurate sideband ratio, and pointing error turned out to be the dominant error sources. Furthermore, the capability of multi-channel simultaneous retrieval from the far infrared and submillimeter data has been investigated. The errors and averaging kernels infer that the quality of the obtained hydrogen chloride (HCl) can be improved by significantly better exploitation of information from the observations.
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Kumar, Ashish, Vinayak Sinha, Muhammed Shabin, Haseeb Hakkim, Bernard Bonsang e Valerie Gros. "Non-methane hydrocarbon (NMHC) fingerprints of major urban and agricultural emission sources for use in source apportionment studies". Atmospheric Chemistry and Physics 20, n. 20 (26 ottobre 2020): 12133–52. http://dx.doi.org/10.5194/acp-20-12133-2020.
Testo completoAbstract (sommario):
Abstract. In complex atmospheric emission environments such as urban agglomerates, multiple sources control the ambient chemical composition driving air quality and regional climate. In contrast to pristine sites, where reliance on single or a few chemical tracers is often adequate for resolving pollution plumes and source influences, the comprehensive chemical fingerprinting of sources using non-methane hydrocarbons (NMHCs) and the identification of suitable tracer molecules and emission ratios becomes necessary. Here, we characterise and present chemical fingerprints of some major urban and agricultural emission sources active in South Asia, such as paddy stubble burning, garbage burning, idling vehicular exhaust and evaporative fuel emissions. A total of 121 whole air samples were actively collected from the different emission sources in passivated air sampling steel canisters and then analysed for 49 NMHCs (22 alkanes, 16 aromatics, 10 alkenes and one alkyne) using thermal desorption gas chromatography flame ionisation detection. Several new insights were obtained. Propane was found to be present in paddy stubble fire emissions (8 %), and therefore, for an environment impacted by crop residue fires, the use of propane as a fugitive liquefied petroleum gas (LPG) emission tracer must be done with caution. Propene was found to be ∼ 1.6 times greater (by weight) than ethene in smouldering paddy fires. Compositional differences were observed between evaporative emissions of domestic LPG and commercial LPG, which are used in South Asia. While the domestic LPG vapours had more propane (40 ± 6 %) than n-butane (19 ± 2 %), the converse was true for commercial LPG vapours (7 ± 6 % and 37 ± 4 %, respectively). Isoprene was identified as a new tracer for distinguishing paddy stubble and garbage burning in the absence of isoprene emissions at night from biogenic sources. Analyses of source-specific inter-NMHC molar ratios revealed that toluene/benzene ratios can be used to distinguish among paddy stubble fire emissions in the flaming (0.38 ± 0.11) and smouldering stages (1.40 ± 0.10), garbage burning flaming (0.26 ± 0.07) and smouldering emissions (0.59 ± 0.16), and traffic emissions (3.54 ± 0.21), whereas i-pentane ∕ n-pentane can be used to distinguish biomass burning emissions (0.06–1.46) from the petrol-dominated traffic and fossil fuel emissions (2.83–4.13). i-butane ∕ n-butane ratios were similar (0.20–0.30) for many sources and could be used as a tracer for photochemical ageing. In agreement with previous studies, i-pentane, propane and acetylene were identified as suitable chemical tracers for petrol vehicular and evaporative emissions, LPG evaporative and vehicular emissions and flaming-stage biomass fires, respectively. The secondary pollutant formation potential and human health impact of the sources was also assessed in terms of their hydroxyl radical (OH) reactivity (s−1), ozone formation potential (OFP; gO3/gNMHC) and fractional benzene, toluene, ethylbenzene and xylenes (BTEX) content. Petrol vehicular emissions, paddy stubble fires and garbage fires were found to have a higher pollution potential (at ≥95 % confidence interval) relative to the other sources studied in this work. Thus, many results of this study provide a new foundational framework for quantitative source apportionment studies in complex emission environments.
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Krasnov, Mikhail M., Natalia D. Novikova, Roger Cattaneo, Alexey A. Kalenyuk e Vladimir M. Krasnov. "Design aspects of Bi2Sr2CaCu2O8+δ THz sources: optimization of thermal and radiative properties". Beilstein Journal of Nanotechnology 12 (21 dicembre 2021): 1392–403. http://dx.doi.org/10.3762/bjnano.12.103.
Testo completoAbstract (sommario):
Impedance matching and heat management are important factors influencing the performance of terahertz sources. In this work we analyze thermal and radiative properties of such devices based on mesa structures of a layered high-temperature superconductor Bi2Sr2CaCu2O8+δ. Two types of devices are considered containing either a conventional large single crystal or a whisker. We perform numerical simulations for various geometrical configurations and parameters and make a comparison with experimental data for the two types of devices. It is demonstrated that the structure and the geometry of both the superconductor and the electrodes play important roles. In crystal-based devices an overlap between the crystal and the electrode leads to appearance of a large parasitic capacitance, which shunts terahertz emission and prevents impedance matching with open space. The overlap is avoided in whisker-based devices. Furthermore, the whisker and the electrodes form a turnstile (crossed-dipole) antenna facilitating good impedance matching. This leads to more than an order of magnitude enhancement of the radiation power efficiency in whisker-based, compared to crystal-based, devices. These results are in good agreement with presented experimental data.
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Roskoss, Alexander. "End to end emissions monitoring by digitalisation". APPEA Journal 63, n. 2 (11 maggio 2023): S442—S445. http://dx.doi.org/10.1071/aj22244.
Testo completoAbstract (sommario):
With hydrocarbon extraction and transmission networks being consumers of energy, there is high sensitivity across the industry towards carbon dioxide and other greenhouse gases being emitted. These emissions need to be measured accurately and reported correctly for commercial and legislative reasons. On any facility there are multiple sources of emissions, both intended and unintended. This paper outlines an approach and technology to measure and report all known sources of emissions consistently accurately, in an auditable and transparent fashion. By calculation of each source’s carbon dioxide or carbon dioxide equivalent mass depending on the nature of the emission source, the total emissions of a site can be reported. The calculation of carbon dioxide from any single emissions source is dependent on numerous factors. For sources which consume hydrocarbons, the mass of carbon dioxide and equivalents in exhausts depends on the hydrocarbon composition, combustion mechanism and combustion efficiency and nature, and any treatments of emissions. The gathering of live process data relating to all these factors directly and indirectly is shown through the treatments described to be effective with general and specific treatments of each factor and the contributing data sources for each is described in some specific examples. The combination of these calculated emissions based on live measurement data for multiple emission sources and their totalisation by emission type, emission source, and the relation of these to other key production factors is described. The validation process of emissions calculations, the totalisations and the analysis of emissions by activity is described.
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López, Fernando M., Carlos Guillermo Giménez de Castro, Cristina H. Mandrini, Paulo J. A. Simões, Germán D. Cristiani, Dale E. Gary, Carlos Francile e Pascal Démoulin. "A solar flare driven by thermal conduction observed in mid-infrared". Astronomy & Astrophysics 657 (gennaio 2022): A51. http://dx.doi.org/10.1051/0004-6361/202141967.
Testo completoAbstract (sommario):
Context. The mid-infrared (mid-IR) range has been mostly unexplored for the investigation of solar flares. It is only recently that new mid-IR flare observations have begun opening a new window into the response and evolution of the solar chromosphere. These new observations have been mostly performed by the AR30T and BR30T telescopes that are operating in Argentina and Brazil, respectively. Aims. We present the analysis of SOL2019-05-15T19:24, a GOES class C2.0 solar flare observed at 30 THz (10 μm) by the ground-based telescope AR30T. Our aim is to characterize the evolution of the flaring atmosphere and the energy transport mechanism in the context of mid-IR emission. Methods. We performed a multi-wavelength analysis of the event by complementing the mid-IR data with diverse ground- and space-based data from the Solar Dynamics Observatory (SDO), the H-α Solar Telescope for Argentina, and the Expanded Owens Valley Solar Array (EOVSA). Our study includes the analysis of the magnetic field evolution of the flaring region and of the development of the flare. Results. The mid-IR images from AR30T show two bright and compact flare sources that are spatially associated with the flare kernels observed in ultraviolet (UV) by SDO. We confirm that the temporal association between mid-IR and UV fluxes previously reported for strong flares is also observed for this small flare. The EOVSA microwave data revealed flare spectra consistent with thermal free-free emission, which lead us to dismiss the existence of a significant number of non-thermal electrons. We thus consider thermal conduction as the primary mechanism responsible for energy transport. Our estimates for the thermal conduction energy and total radiated energy fall within the same order of magnitude, reinforcing our conclusions.
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Foteinopoulou, Stavroula, Ganga Chinna Rao Devarapu, Ganapathi S. Subramania, Sanjay Krishna e Daniel Wasserman. "Phonon-polaritonics: enabling powerful capabilities for infrared photonics". Nanophotonics 8, n. 12 (17 ottobre 2019): 2129–75. http://dx.doi.org/10.1515/nanoph-2019-0232.
Testo completoAbstract (sommario):
AbstractHere, we review the progress and most recent advances in phonon-polaritonics, an emerging and growing field that has brought about a range of powerful possibilities for mid- to far-infrared (IR) light. These extraordinary capabilities are enabled by the resonant coupling between the impinging light and the vibrations of the material lattice, known as phonon-polaritons (PhPs). These PhPs yield a characteristic optical response in certain materials, occurring within an IR spectral window known as the reststrahlen band. In particular, these materials transition in the reststrahlen band from a high-refractive-index behavior, to a near-perfect metal behavior, to a plasmonic behavior – typical of metals at optical frequencies. When anisotropic they may also possess unconventional photonic constitutive properties thought of as possible only with metamaterials. The recent surge in two-dimensional (2D) material research has also enabled PhP responses with atomically-thin materials. Such vast and extraordinary photonic responses can be utilized for a plethora of unusual effects for IR light. Examples include sub-diffraction surface wave guiding, artificial magnetism, exotic photonic dispersions, thermal emission enhancement, perfect absorption and enhanced near-field heat transfer. Finally, we discuss the tremendous potential impact of these IR functionalities for the advancement of IR sources and sensors, as well as for thermal management and THz-diagnostic imaging.
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Mustafaev, Islam I., Lala Y. Jabbarova e Zargalam O. Nabizade. "Инвентаризация источников поступления ртути в окружающую среду в Азербайджане". Химическая безопасность / Chemical Safety Science 5, n. 2 (17 dicembre 2021): 272–91. http://dx.doi.org/10.25514/chs.2021.2.20017.
Testo completoAbstract (sommario):
Mercury is one of the most toxic metals and is widely used in the environment. It is a heavy liquid metal, which contains extremely dangerous substances that pollute the atmosphere, water, food. Sources of mercury emissions - mining and smelting of mercury-containing ores from sulphide ores, extraction of non-ferrous metals, gold from ore, bleaching of cellulose, chlorine, caustic, vinyl chloride, electrical equipment (lamps, various power sources), measuring and control devices (thermometer, monometer), mercury-containing preparations, cement production , use of mercury-containing pesticides, combustion of coal and fuel oil. Significant amounts of mercury are also released into the environment during waste incineration. The results of the inventory of mercury emissions in Azerbaijan are presented. There were analyzed all the main areas of national industry of Azerbaijan, in which the presence of mercury, conducted quantitative assessments, and in some cases revealed their trends. One of the obligations in accordance with the requirements of the Minamata Convention is the creation of an inventory of emissions into the environment "Mercury" prepared by the United Nations Environment Program (UNEP Chemicals - Waste). To create a cadastre, all the main trends in the national industry of Azerbaijan were analyzed. The overall health impact of mercury is assessed. Ртуть это один из самых токсичных металлов, широко используемый в промышленности и повседневной жизни. Это тяжелый жидкий металл, пары и некоторые соединения которого чрезвычайно опасные вещества, загрязняющие атмосферу, воду, пищу. Источники выбросов ртути: добыча и выплавка ртутьсодержащих руд из сульфидных руд, извлечение цветных металлов, золота из руды, отбеливание целлюлозы, производство хлора, каустика, винилхлорида, электрооборудование, измерительные приборы, ртутьсодержащие препараты, производство цемента, использование ртутьсодержащих пестицидов, сжигание угля и мазута. Значительные количества ртути также выбрасываются в окружающую среду при сжигании отходов. Представлены результаты инвентаризации источников поступления ртути в Азербайджане. Одним из обязательств в соответствии с требованиями Минаматской конвенции является создание кадастра выбросов ртути в окружающую среду «Ртуть», подготовленный Программой ООН по окружающей среде (UNEP Chemicals - Waste). Для создания кадастра были проанализированы все основные области национальной промышленности Азербайджана, в которых вероятно присутствие ртути, проведены количественные оценки, а в некоторых случаях выявлены их тенденции. Приводится оценка общего воздействия ртути на здоровье человека.
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Pacyna, Jozef M., M. Trevor Scholtz e Y. F. (Arthur) Li. "Global budget of trace metal sources". Environmental Reviews 3, n. 2 (1 aprile 1995): 145–59. http://dx.doi.org/10.1139/a95-006.
Testo completoAbstract (sommario):
Global emission inventories, being the key information for the global budgets of trace metals, have become available only recently. The latest information on emissions and sources of trace metals on a global scale is presented in this paper. As the global assessments are prepared on the basis of estimates of regional emissions, these latter data are also reviewed here. A comparison of the worldwide atmospheric emissions from natural and anthropogenic sources suggests that various human activities are the dominant source of many trace metals, including As, Cd, Pb, and Zn. A comparison of the atmospheric and aquatic emissions indicates that, for most of the trace metals, the annual anthropogenic inputs into water exceed the quantities emitted to the atmosphere. However, the largest quantities of trace metals are discharged to the terrestrial environment. So far, the Pb budget seems to be the most accurate owing to a large body of information available on this element. The largest emissions of Pb were estimated for gasoline combustion, contributing about two thirds of the total emissions to the atmosphere. Emissions from nonferrous metal production contributed about one quarter. Emissions from the European and Asian sources contributed each about one third of the global emissions, followed by emissions from sources in North America. A spatial distribution of the global Pb emissions is presented within a 1 × 1° grid system.Key words: trace metals, lead, global emission, emission map.
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Kholod, Nazar, Meredydd Evans e Teresa Kuklinski. "Russia's black carbon emissions: focus on diesel sources". Atmospheric Chemistry and Physics 16, n. 17 (12 settembre 2016): 11267–81. http://dx.doi.org/10.5194/acp-16-11267-2016.
Testo completoAbstract (sommario):
Abstract. Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25–30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.
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Kasseh, Y., A. Touzani e S. EL Majaty. "Production of a Database on Short-Lived Climate Pollutants (SLCP) and the Elaboration of Projection Scenarios of these Emissions Using the LEAP Software - The Case of Morocco". Nature Environment and Pollution Technology 22, n. 4 (1 dicembre 2023): 2103–10. http://dx.doi.org/10.46488/nept.2023.v22i04.035.
Testo completoAbstract (sommario):
Short-lived climate pollutants (SLCPs) have significant effects on climate, human health, and the environment. In Morocco, steps are being taken to reduce SLCP emissions, but effective policymaking requires a thorough understanding of emission sources and trends. In this paper, we present a study on the production of a database on SLCP emissions in Morocco, as well as the development of scenarios to project these emissions using LEAP software. The results of this analysis allow us to better understand the emissions sources and evaluate the impact of different emission reduction policies.
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Yang, Deai, Mingjun Li, Xingyi Geng e Zhihui Feng. "Sources and Specified Health Risks of 12 PM2.5-Bound Metals in a Typical Air-Polluted City in Northern China during the 13th Five-Year Plan". Toxics 12, n. 8 (10 agosto 2024): 581. http://dx.doi.org/10.3390/toxics12080581.
Testo completoAbstract (sommario):
The continuous monitoring of PM2.5 (including 12 metal elements) was conducted in Jinan, a city with poor air quality in China, during the 13th Five-Year Plan (2016–2020). Positive matrix factorization (PMF) was used to identify emission sources of PM2.5-bound metals, and the health risks of the metals and their emission sources were assessed. During the study period, the concentration of most metals showed a decreasing trend (except Al and Be), and a significant seasonal difference was found: winter > fall > spring > summer. The PMF analysis showed that there were four main sources of PM2.5-bound metals, and their contributions to the total metals (TMs) were dust emissions (54.3%), coal combustion and industrial emissions (22.3%), vehicle emissions (19.3%), and domestic emissions (4.1%). The results of the health risk assessment indicated that the carcinogenic risk of metals (Cr and As) exceeded the acceptable level (1 × 10−6), which was of concern. Under the influence of emission reduction measures, the contribution of emission sources to health risks changes dynamically, and the emission sources that contribute more to health risks were coal combustion and industrial emissions, as well as vehicle emissions. In addition, our findings suggest that a series of emission reduction measures effectively reduced the health risk from emission sources of PM2.5-bound metals.
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Shusterman, Alexis A., Jinsol Kim, Kaitlyn J. Lieschke, Catherine Newman, Paul J. Wooldridge e Ronald C. Cohen. "Observing local CO<sub>2</sub> sources using low-cost, near-surface urban monitors". Atmospheric Chemistry and Physics 18, n. 18 (28 settembre 2018): 13773–85. http://dx.doi.org/10.5194/acp-18-13773-2018.
Testo completoAbstract (sommario):
Abstract. Urban carbon dioxide comprises the largest fraction of anthropogenic greenhouse gas emissions, but quantifying urban emissions at subnational scales is highly challenging, as numerous emission sources reside in close proximity within each topographically intricate urban dome. In attempting to better understand each individual source's contribution to the overall emission budget, there exists a large gap between activity-based emission inventories and observational constraints on integrated, regional emission estimates. Here we leverage urban CO2 observations from the BErkeley Atmospheric CO2 Observation Network (BEACO2N) to enhance, rather than average across or cancel out, our sensitivity to these hyperlocal emission sources. We utilize a method for isolating the local component of a CO2 signal that accentuates the observed intra-urban heterogeneity and thereby increases sensitivity to mobile emissions from specific highway segments. We demonstrate a multiple-linear-regression analysis technique that accounts for boundary layer and wind effects and allows for the detection of changes in traffic emissions on scale with anticipated changes in vehicle fuel economy – an unprecedented level of sensitivity for low-cost sensor technologies. The ability to represent trends of policy-relevant magnitudes with a low-cost sensor network has important implications for future applications of this approach, whether as a supplement to existing, sparse reference networks or as a substitute in areas where fewer resources are available.
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Gołasa, Piotr, Marcin Wysokiński, Wioletta Bieńkowska-Gołasa, Piotr Gradziuk, Magdalena Golonko, Barbara Gradziuk, Agnieszka Siedlecka e Arkadiusz Gromada. "Sources of Greenhouse Gas Emissions in Agriculture, with Particular Emphasis on Emissions from Energy Used". Energies 14, n. 13 (23 giugno 2021): 3784. http://dx.doi.org/10.3390/en14133784.
Testo completoAbstract (sommario):
The relationship between agriculture and climate change is two-sided. Agriculture is the branch of the economy most affected by the ongoing processes. It is also a large emitter of greenhouse gases and there are more and more voices about the need to reduce emissions. The purpose of the study was, based on FADN (Farm Accountancy Data Network) data, to determine the structure of greenhouse gas emissions in farms and to identify types of farms where it is possible to reduce GHG (greenhouse gas) emissions through better energy use. The emission volume was determined on the basis of the IPCC (Intergovernmental Panel on Climate Change) methodology modified for the FADN data. The emissions related to the production of energy were found to be of minor importance compared to other emission sources. Only in the horticultural crop type is the emission from the Energy section the dominant stream of GHG emission. The greatest emissions come from livestock production. Therefore, the emphasis on reducing emissions should not be placed on the Energy sector because, except for the type of horticultural farm, there is not much potential for reduction. The introduction of taxes for GHG emissions at the level of 27.31 EUR/t would reduce farm income from 21% for the type of field crops to 40% for the type of herbivorous animals. The exception is low-emission permanent crops, where the decrease in income would be only 3.85%.
42
Ohara, T., H. Akimoto, J. Kurokawa, N. Horii, K. Yamaji, X. Yan e T. Hayasaka. "An Asian emission inventory of anthropogenic emission sources for the period 1980–2020". Atmospheric Chemistry and Physics Discussions 7, n. 3 (22 maggio 2007): 6843–902. http://dx.doi.org/10.5194/acpd-7-6843-2007.
Testo completoAbstract (sommario):
Abstract. We developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980–2020. REAS is the first inventory to integrate historical, present, and future emissions in Asia on the basis of a consistent methodology. We present here emissions in 2000, historical emissions for 1980–2003, and projected emissions for 2010 and 2020 of SO2, NOx, CO, NMVOC, black carbon (BC), and organic carbon (OC) from fuel combustion and industrial sources. Total energy consumption in Asia more than doubled between 1980 and 2003, causing a rapid growth in Asian emissions, by 28% for BC, 30% for OC, 64% for CO, 108% for NMVOC, 119% for SO2, and 176% for NOx. In particular, Chinese NOx emissions showed a marked increase of 280% over 1980 levels, and growth in emissions since 2000 has been extremely high. These increases in China were mainly caused by increases in coal combustion in the power plants and industrial sectors. NMVOC emissions also rapidly increased because of growth in the use of automobiles, solvents, and paints. By contrast, BC, OC, and CO emissions in China showed decreasing trends from 1996 to 2000 because of a reduction in the use of biofuels and coal in the domestic and industry sectors. However, since 2000, Chinese emissions of these species have begun to increase. Thus, the emissions of air pollutants in Asian countries (especially China) showed large temporal variations from 1980–2003. Future emissions in 2010 and 2020 in Asian countries were projected by emission scenarios and from emissions in 2000. For China, we developed three emission scenarios: PSC (policy success case), REF (reference case), and PFC (policy failure case). In the 2020 REF scenario, Asian total emissions of SO2, NOx, and NMVOC were projected to increase substantially by 22%, 44%, and 99%, respectively, over 2000 levels. The 2020 REF scenario showed a modest increase in CO (12%), a lesser increase in BC (1%), and a slight decrease in OC (–5%) compared with 2000 levels. However, it should be noted that Asian total emissions are strongly influenced by the emission scenarios for China.
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Ohara, T., H. Akimoto, J. Kurokawa, N. Horii, K. Yamaji, X. Yan e T. Hayasaka. "An Asian emission inventory of anthropogenic emission sources for the period 1980–2020". Atmospheric Chemistry and Physics 7, n. 16 (23 agosto 2007): 4419–44. http://dx.doi.org/10.5194/acp-7-4419-2007.
Testo completoAbstract (sommario):
Abstract. We developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980–2020. REAS is the first inventory to integrate historical, present, and future emissions in Asia on the basis of a consistent methodology. We present here emissions in 2000, historical emissions for 1980–2003, and projected emissions for 2010 and 2020 of SO2, NOx, CO, NMVOC, black carbon (BC), and organic carbon (OC) from fuel combustion and industrial sources. Total energy consumption in Asia more than doubled between 1980 and 2003, causing a rapid growth in Asian emissions, by 28% for BC, 30% for OC, 64% for CO, 108% for NMVOC, 119% for SO2, and 176% for NOx. In particular, Chinese NOx emissions showed a marked increase of 280% over 1980 levels, and growth in emissions since 2000 has been extremely high. These increases in China were mainly caused by increases in coal combustion in the power plants and industrial sectors. NMVOC emissions also rapidly increased because of growth in the use of automobiles, solvents, and paints. By contrast, BC, OC, and CO emissions in China showed decreasing trends from 1996 to 2000 because of a reduction in the use of biofuels and coal in the domestic and industry sectors. However, since 2000, Chinese emissions of these species have begun to increase. Thus, the emissions of air pollutants in Asian countries (especially China) showed large temporal variations from 1980–2003. Future emissions in 2010 and 2020 in Asian countries were projected by emission scenarios and from emissions in 2000. For China, we developed three emission scenarios: PSC (policy success case), REF (reference case), and PFC (policy failure case). In the 2020 REF scenario, Asian total emissions of SO2, NOx, and NMVOC were projected to increase substantially by 22%, 44%, and 99%, respectively, over 2000 levels. The 2020 REF scenario showed a modest increase in CO (12%), a lesser increase in BC (1%), and a slight decrease in OC (−5%) compared with 2000 levels. However, it should be noted that Asian total emissions are strongly influenced by the emission scenarios for China.
44
Yu, Tai Yi, I. Cheng Chang, Mei Yin Hwa e Li Teh Lu. "Estimation of Air Pollutant Emissions from Mobile Sources with Three Emission Factors Models". Advanced Materials Research 550-553 (luglio 2012): 2378–81. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2378.
Testo completoAbstract (sommario):
Vehicle emissions from mobile sources are major contributors to air pollution and varied with vehicle types, vehicle styles, traveled miles, temperature, oil types and the methods of operation and management. This study performs three emission factor models, Mobile-Taiwan 2, Mobile6.2 and EFDB to calculate emission factor of mobile sources from year 1986 to 2011. The emissions of primary air pollutants, MIRs and CO2emitted from mobile sources were calculated. The contribution ratios of varied vehicle types for different air pollutants would be compared and analyzed. Estimated emissions from mobile sources were 32.2, 177, 643, 197 and 401 kilotons/y for PM10, NOx, CO, THC and MIR for 2000; 31.3, 115, 305, 114 and 227 kilotons/y for 2011. Emissions of traditional air pollutants presented a decreasing trend because of fourth-stage emission standards for mobiles sources and CO2 revealed an increasing trend. According to presented control technology for greenhouse gases on mobile sources, ratio of emission for year 2011 to 2000 would be 1.38-1.49.
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Леонович, Людмила, Lyudmila Leonovich, Анатолий Тащилин, Anatoliy Tashchilin, Сергей Лунюшкин, Sergey Lunyushkin, Юрий Караваев, Yuriy Karavaev, Юрий Пенских e Yury Penskikh. "Studying 630 nm atomic oxygen emission sources during strong magnetic storms in the night mid-latitude ionosphere". Solar-Terrestrial Physics 5, n. 2 (28 giugno 2019): 33–38. http://dx.doi.org/10.12737/stp-52201905.
Testo completoAbstract (sommario):
We analyze significant increases in 630 nm atomic oxygen night emissions during very strong geomagnetic storms, using optical measurements, theoretical modeling, and magnetogram inversion technique (MIT) data. It is shown that during strong magnetic storms when electron precipitation equatorial boundary at the night sector expands up to ~40°, the interaction of energetic electron flux with thermospheric components may cause extreme increases in the 630 nm emission intensity. Model calculations of the red line intensity show good agreement with observational data. Using the November 20, 2003 magnetic storm as an example, we have found that oxygen atom collisions with thermal Maxwell and superthermal electrons make a major contribution to the integral emission intensity. Thermospheric density variations during the magnetic storm significantly affect the red line generation.
46
Gaimoz, Cécile, Stéphane Sauvage, Valérie Gros, Frank Herrmann, Jonathan Williams, Nadine Locoge, Olivier Perrussel et al. "Volatile organic compounds sources in Paris in spring 2007. Part II: source apportionment using positive matrix factorisation". Environmental Chemistry 8, n. 1 (2011): 91. http://dx.doi.org/10.1071/en10067.
Testo completoAbstract (sommario):
Environmental context Volatile organic compounds are key compounds in atmospheric chemistry as precursors of ozone and secondary organic aerosols. To determine their impact at a megacity scale, a first important step is to characterise their sources. We present an estimate of volatile organic compound sources in Paris based on a combination of measurements and model results. The data suggest that the current emission inventory strongly overestimates the volatile organic compounds emitted from solvent industries, and thus needs to be corrected. Abstract A positive matrix factorisation model has been used for the determination of volatile organic compound (VOC) source contributions in Paris during an intensive campaign (May–June 2007). The major sources were traffic-related emissions (vehicle exhaust, 22% of the total mixing ratio of the measured VOCs, and fuel evaporation, 17%), with the remaining emissions from remote industrial sources (35%), natural gas and background (13%), local sources (7%), biogenic and fuel evaporation (5%) and wood-burning (2%). It was noted that the remote industrial contribution was highly dependent on the air-mass origin. During the period of oceanic influences (when only local and regional pollution was observed), this source made a relatively low contribution (<15%), whereas the source contribution linked to traffic was high (54%). During the period of continental influences (when additional continental pollution was observed), remote industrial sources played a dominant role, contributing up to 50% of measured VOCs. Finally, the positive matrix factorisation results obtained during the oceanic air mass-influenced period were compared with the local emission inventory. This comparison suggests that the VOC emission from solvent industries might be overestimated in the inventory, consistent with findings in other European cities.
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Beuther, H., N. Schneider, R. Simon, S. Suri, V. Ossenkopf-Okada, S. Kabanovic, M. Röllig et al. "FEEDBACK from the NGC 7538 H II region". Astronomy & Astrophysics 659 (marzo 2022): A77. http://dx.doi.org/10.1051/0004-6361/202142689.
Testo completoAbstract (sommario):
Context. The interaction of expanding H II regions with their environmental clouds is one of the central questions driving the Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy program FEEDBACK. Aims. We want to understand the interaction of the prototypical NGC 7538 H II region with the neighboring molecular cloud hosting several active star-forming regions. Methods. Using the SOFIA, we mapped an area of ~210′2 (~125 pc2) around NGC 7538 in the velocity-resolved ionized carbon fine-structure line [CII] at 1.9 THz (158 μm). Complementary observed atomic carbon [CI] at 492 GHz and high-J CO(8–7) data, as well as archival near- and far-infrared, cm continuum, CO(3–2), and HI data are folded into the analysis. Results. The ionized carbon [CII] data reveal rich morphological and kinematic structures. While the overall morphology follows the general ionized gas that is also visible in the radio continuum emission, the channel maps show multiple bubble-like structures with sizes on the order of ~80–100″ (~1.0–1.28 pc). While at least one of them may be an individual feedback bubble driven by the main exciting sources of the NGC 7538 H II region (the O3 and O9 stars IRS6 and IRS5), the other bubble-like morphologies may also be due to the intrinsically porous structure of the H II region. An analysis of the expansion velocities around 10 km s−1 indicates that thermal expansion is not sufficient but that wind-driving from the central O-stars is required. The region exhibits a general velocity gradient across, but we also identify several individual velocity components. The most blue-shifted [CII] component has barely any molecular or atomic counterparts. At the interface to the molecular cloud, we find a typical photon-dominated region (PDR) with a bar-shape. Ionized C+, atomic C0 and molecular carbon CO show a layered structure in this PDR. The carbon in the PDR is dominated by its ionized C+ form with atomic C0 and molecular CO masses of ~0.45 ± 0.1 M⊙ and ~1.2 ± 0.1 M⊙, respectively, compared to the ionized carbon C+ in the range of 3.6−9.7 M⊙. This bar-shaped PDR exhibits a velocity-gradient across, indicating motions along the line of sight toward the observer. Conclusions. Even if it is shown to be dominated by two nearby exciting sources (IRS6 and IRS5), the NGC 7538 H II region exhibits a diverse set of substructures that interact with each other as well as with the adjacent cloud. Compared to other recent [CII] observations of H II regions (e.g., Orion Veil, RCW120, RCW49), the bubble-shape morphologies revealed in [CII] emission that are indicative of expanding shells are recurring structures of PDRs.
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Wójcik-Gront, Elżbieta. "Analysis of Sources and Trends in Agricultural GHG Emissions from Annex I Countries". Atmosphere 11, n. 4 (15 aprile 2020): 392. http://dx.doi.org/10.3390/atmos11040392.
Testo completoAbstract (sommario):
The vast majority of the scientific community believe that anthropogenic greenhouse gas (GHG) emissions are the predominant cause of climate change. One of the GHG emission sources is agriculture. Following the International Panel on Climate Change (IPCC) guidelines regarding GHG emission calculation, agriculture is responsible for around 10% of the overall global emissions. Agricultural GHG emissions consist of several emission source categories and several GHGs. In this article were described the results of multivariate statistical analyses performed on data gathered during the period 1990–2017 from the inventories of 43 Annex I countries (parties to the United Nations Framework Convention on Climate Change, UNFCCC, listed in Annex I of the Convention). Trends in the agricultural GHG emissions were analyzed. Generally, the global agricultural GHG emissions are increasing, while the emissions from Annex I countries are decreasing. Apart from the application of urea, emissions from all other sources, such as enteric fermentation, manure management, rice cultivation, agricultural soils, field burning of agricultural residues, and liming are decreasing. Based on multivariate analysis, the most different countries, in terms of GHG emission sources composition in agriculture and emission trends, are Australia, Japan, New Zealand and USA. The rest of the Annex I countries are mostly from Europe and their shares and trends are similar, with slight differences between countries depending, among others, on the date of joining the European Union.
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Pirrone, N., S. Cinnirella, X. Feng, R. B. Finkelman, H. R. Friedli, J. Leaner, R. Mason et al. "Global mercury emissions to the atmosphere from anthropogenic and natural sources". Atmospheric Chemistry and Physics Discussions 10, n. 2 (16 febbraio 2010): 4719–52. http://dx.doi.org/10.5194/acpd-10-4719-2010.
Testo completoAbstract (sommario):
Abstract. This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr−1), artisanal small scale gold mining (400 Mg yr−1), non-ferrous metals manufacturing (310 Mg yr−1), cement production (236 Mg yr−1), waste disposal (187 Mg yr−1) and caustic soda production (163 Mg yr−1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions+re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.
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Pirrone, N., S. Cinnirella, X. Feng, R. B. Finkelman, H. R. Friedli, J. Leaner, R. Mason et al. "Global mercury emissions to the atmosphere from anthropogenic and natural sources". Atmospheric Chemistry and Physics 10, n. 13 (2 luglio 2010): 5951–64. http://dx.doi.org/10.5194/acp-10-5951-2010.
Testo completoAbstract (sommario):
Abstract. This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr−1), artisanal small scale gold mining (400 Mg yr−1), non-ferrous metals manufacturing (310 Mg yr−1), cement production (236 Mg yr−1), waste disposal (187 Mg yr−1) and caustic soda production (163 Mg yr−1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions + re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.