A large sample of spectroscopically confirmed star-forming galaxies at redshifts 1.4 < or =, slant z sub(spec) < or =, slant 3.7, with complementary imaging in the near- and mid-IR from the ground ...and from the Hubble Space Telescope and Spitzer Space Telescope, is used to infer the average star formation histories (SFHs) of typical galaxies from z ~ 2 to 7. We interpret this result in the context of several systematic biases that can affect determinations of the SFR-M* relation. The average specific SFRs at z ~ 2-3 are remarkably similar within a factor of two to those measured at z gap 4, implying that the average SFH is one where SFRs increase with time. These results highlight the relative inefficiency of star formation even at early cosmic times when galaxies were first assembling.
Photothermal therapy is a kind of therapy based on increasing the temperature of tumoral cells above 42 °C. To this aim, cells must be illuminated with a laser, and the energy of the radiation is ...transformed in heat. Usually, the employed radiation belongs to the near-infrared radiation range. At this range, the absorption and scattering of the radiation by the body is minimal. Thus, tissues are almost transparent. To improve the efficacy and selectivity of the energy-to-heat transduction, a light-absorbing material, the photothermal agent, must be introduced into the tumor. At present, a vast array of compounds are available as photothermal agents. Among the substances used as photothermal agents, gold-based compounds are one of the most employed. However, the undefined toxicity of this metal hinders their clinical investigations in the long run. Magnetic nanoparticles are a good alternative for use as a photothermal agent in the treatment of tumors. Such nanoparticles, especially those formed by iron oxides, can be used in combination with other substances or used themselves as photothermal agents. The combination of magnetic nanoparticles with other photothermal agents adds more capabilities to the therapeutic system: the nanoparticles can be directed magnetically to the site of interest (the tumor) and their distribution in tumors and other organs can be imaged. When used alone, magnetic nanoparticles present, in theory, an important limitation: their molar absorption coefficient in the near infrared region is low. The controlled clustering of the nanoparticles can solve this drawback. In such conditions, the absorption of the indicated radiation is higher and the conversion of energy in heat is more efficient than in individual nanoparticles. On the other hand, it can be designed as a therapeutic system, in which the heat generated by magnetic nanoparticles after irradiation with infrared light can release a drug attached to the nanoparticles in a controlled manner. This form of targeted drug delivery seems to be a promising tool of chemo-phototherapy. Finally, the heating efficiency of iron oxide nanoparticles can be increased if the infrared radiation is combined with an alternating magnetic field.
The Arctic has been warming faster than elsewhere, especially during the cold season. According to the leading theory, ice‐albedo feedback warms the Arctic Ocean during the summer, and the heat ...gained by the ocean is released during the winter, causing the cold‐season warming. Screen and Simmonds (2010; SS10) concluded that the theory is correct by comparing trend patterns in surface air temperature (SAT), surface turbulence heat flux (HF), and net surface infrared radiation (IR). However, in this comparison, downward IR is more appropriate to use. By analyzing the same data used in SS10 using the surface energy budget, it is shown here that over most of the Arctic the skin temperature trend, which closely resembles the SAT trend, is largely accounted for by the downward IR, not the HF, trend.
Key Points
Surface temperature should be compared with downward infrared radiation and not net infrared radiation
The Arctic surface temperature trend is driven primarily by downward infrared radiation and not surface turbulent fluxes
The downward infrared radiation trend is associated with the intraseasonal moisture intrusion trend
Plain Language Summary
The Arctic has been warming faster than elsewhere, especially during the fall and winter. According to the leading theory, ice‐albedo feedback warms the Arctic Ocean during the summer, and the heat gained by the ocean is released during the fall and winter, causing warming in these seasons. Deviating from this theory, it is shown here that over most of the Arctic, the skin temperature trend, which closely resembles the SAT trend, is largely accounted for by the downward infrared radiation, not the ocean‐to‐atmosphere heat flux, trend.
Gel-nanocomposites are rapidly emerging functional advanced materials having widespread applications in materials and biological sciences. Herein, we review syntheses, properties, and applications of ...various gel-nanocomposites assembled from different metal-based nanoparticles or nanocarbons fullerene, carbon nanotubes (CNTs), and graphenes with tailor-made supramolecular (small molecular) or polymeric physical organogels and hydrogels. Dynamic supramolecular self-assembly of gelators prove to be excellent hosts for the incorporation of these dimensionally different nanomaterials. Thus, gel-nanocomposites doped with preformed/in situ synthesized nanoparticles show magnetic or near-infrared-responsive, catalytic or antibacterial properties. Fullerene-based gel-nanocomposites show applications in organic solar cells. Gel-nanocomposites based on CNTs and graphenes and their functionalized (covalent/noncovalent) analogues find interesting properties including electrical conductivity, viscoelasticity, thermal robustness, magnetic, phase-selective, redox and near-infrared radiation sensitive properties. We present appropriate rationale to explain most of these phenomena at the molecular level, which provide useful perspectives for future designs and new spin-offs. Finally, a possible outlook is projected for the design and syntheses of next generation multifunctional gel-nanocomposites, which could be achieved by increasing the complexity of the system upon adding selective nanomaterials with desired properties in a multicomponent mixture following a de novo design in order to take advantage of their individual properties.
Moisture variation and fissure formation of rice kernels during multi-stage intermittent drying (MSID) were simulated and analyzed based on the experimental data obtained in a laboratory-scale ...infrared-assisted vibratory bed dryer. The variations of drying parameters included far-infrared radiation (FIR) intensity (0, 1000 and 2000 W m
−2
), inlet drying air temperature (30, 40 and 50 °C), drying duration (15, 30 and 40 min), and tempering ratio (0, 2, 4 and 6). Two-dimensional moisture distribution within individual kernel was predicted. Drying rate, percentage of the cracked kernel (PCK), and specific energy consumption (SEC) were also determined, experimentally. By assessing PCK and SEC and simulation results, it was found that the magnitude of 10% d.b. mm
−1
was considered as an index for the critical value for moisture content gradient (MCG) to achieve the suitable drying and tempering duration. It was further recommended that the intermittent drying duration at each stage should be selected in such a way that the MCG value does not exceed the critical level and the shortest possible tempering duration should be chosen in a manner that at least 40% of critical level of MCG be eliminated. The suitable treatment for intermittent drying was selected at FIR intensity of 1000 W m
−2
, inlet air temperature in 40 °C, drying duration in 30 min, and tempering ratio in 4.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Radiative cooling materials spontaneously radiate long-wave infrared (LWIR) to the cold outer space, providing cooling power that is preferred in hot seasons. Radiative cooling has been widely ...explored for walls and roofs but rarely for windows, which are one of the least energy-efficient parts of buildings. We fabricated scalable smart windows using a solution process giving different emissivity (ε) at high (ε
of 0.61) and low (ε
of 0.21) temperatures to regulate radiative cooling automatically while maintaining luminous transparency and near-infrared (NIR) modulation. These passive and independent visible–NIR–LWIR regulated smart windows are capable of dynamic radiative cooling for self-adapting applications across different climate zones.
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•A review of the state-of-the-art coating technologies for glazing applications is reported.•Static coating technologies with fixed optical properties are compared to dynamic ...coatings.•Electrothermal coatings and photothermal coatings are compared.•Recent evolution in electrochromic and gasochromic coatings is reported.•An ideal passive dynamic hybrid photo-thermochromic coating on flexible films is presented.
This paper presents a comprehensive review of the current state-of-the-art coating technologies for glazing applications. The main objective is to collect and present current commercially available technologies on today's market and future research prototypes to identify the most promising coating technologies. Several static coating technologies with fixed optical properties are compared, including low emissivity, electrothermal and photothermal coatings. Low-E coatings are the current industry standard and have almost reached their full energy-saving potential. Hence, electrothermal coatings that convert electricity to heat by the Joule effect are discussed, together with their limitations of needed power supply. To overcome these issues, photothermal coatings have been proposed to improve the glazing thermal performance by absorption of ultra-violet and near-infrared radiation. On the other hand, dynamic coatings can modulate solar gains by switching between clear and tinted states in response to external stimuli. Electrochromic and gasochromic coatings are still limited by high costs. In comparison, photochromic and thermochromic coatings are more accessible and less complex passive technologies, although photochromic coatings are still hindered by low bleaching rates and poor cyclic stabilities. In comparison, thermochromic coatings are more mature, especially those based on vanadium dioxide. This review shows that both static and dynamic technologies thrive to enhance optical and thermal performances while providing an opportunity for the realization of durable next-generation dynamic windows. In particular, the development of passive dynamic hybrid photo-thermochromic coatings seems the most promising trajectory.
Triplet-triplet annihilation based molecular photon upconversion (TTA-UC) is an exciting research area for a broad range of photonic applications due to its tunable spectral range and possible ...operation at non-coherent solar irradiance. Most of the TTA-UC studies are limited to Visible to Visible (Vis to Vis) energy upconversion. However, for several practical photonic applications, efficient near infrared (NIR) to Vis upconversion is preferred. Examples include, (i) photovoltaics where TTA-UC could lead to utilization of a larger part of the solar spectrum and (ii) in NIR stimulated biological applications where the deep penetration and non-invasive nature of NIR light coupled to TTA-UC offers new opportunities. Although, NIR to Vis TTA-UC is known since 2007, the recent five years have witnessed quite a progress in terms of the development of new chromophores, hybrid systems and fabrication techniques to increase the UC quantum yield at low excitation intensity. With this tutorial review we are reviewing recent progress, identifying existing challenges and discus possible future directions and opportunities.
This review delineates the developments in triplet-triplet annihilation based NIR to Vis molecular photon upconversion including recent progress in conceptual design, applications, existing challenges, possible future directions and opportunities.
A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules ...has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.Improved understanding of passivation leads to near-infrared perovskite light-emitting diodes with 21.6% external quantum efficiency.
ABSTRACT We used the Atacama Large Millimeter Array (ALMA) to map the emission of the CO(6-5) molecular line and the 432 m continuum emission from the 300 pc sized circumnuclear disk (CND) of the ...nearby Seyfert 2 galaxy NGC 1068 with a spatial resolution of ∼4 pc. These observations spatially resolve the CND and, for the first time, image the dust emission, the molecular gas distribution, and the kinematics from a 7-10 pc diameter disk that represents the submillimeter counterpart of the putative torus of NGC 1068. We fitted the nuclear spectral energy distribution of the torus using ALMA and near- and mid-infrared (NIR/MIR) data with CLUMPY torus models. The mass and radius of the best-fit solution for the torus are both consistent with the values derived from the ALMA data alone: M gas torus = ( 1 0.3 ) × 10 5 M ☉ and Rtorus = 3.5 0.5 pc. The dynamics of the molecular gas in the torus show strong non-circular motions and enhanced turbulence superposed on a surprisingly slow rotation pattern of the disk. By contrast with the nearly edge-on orientation of the H2O megamaser disk, we found evidence suggesting that the molecular torus is less inclined (i = 34°-66°) at larger radii. The lopsided morphology and complex kinematics of the torus could be the signature of the Papaloizou-Pringle instability, long predicted to likely drive the dynamical evolution of active galactic nuclei tori.
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