Light-emitting diodes (LEDs) are attracting considerable attention around the world. Phosphor materials, as crucial color-converted components, play central roles in LED development. The demands for ...phosphor materials have become increasingly stringent over the past decades, from high brightness to narrowband emission or function-dependent spectrum engineering. Although substantial progress has been made for currently developed phosphor materials, simultaneously satisfying all requirements for high-level applications remains challenging. In this review, we aim to provide a comprehensive understanding of the development of phosphor materials in different generations and to elucidate the key designed mechanisms concerning the activators and the host structures to fulfill the aforementioned aspects. We highlight the developments in phosphor materials through the classification of demands for high luminescence, high thermal stability, narrowband emission for high color gamut, and broadband emission for near-infrared. We also focus on elucidating the key designed mechanisms of phosphor materials in different generations. Furthermore, future perspectives about micro-LED applications and nanoluminescent materials are provided. This study opens up an avenue for designing the luminescent materials of the future.
We present deep near-IR (NIR) medium-bandwidth photometry over the wavelength range 1-1.8 Delta *mm in the All-wavelength Extended Groth strip International Survey (AEGIS) and Cosmic Evolution Survey ...(COSMOS) fields. The observations were carried out using the NOAO Extremely Wide-Field Infrared Imager (NEWFIRM) on the Mayall 4 m Telescope on Kitt Peak as part of the NEWFIRM Medium-Band Survey (NMBS), an NOAO survey program. In this paper, we describe the full details of the observations, data reduction, and photometry for the survey. We also present a public K-selected photometric catalog, along with accurate photometric redshifts. The redshifts are computed with 37 (20) filters in the COSMOS (AEGIS) fields, combining the NIR medium-bandwidth data with existing UV (Galaxy Evolution Explorer), visible and NIR (Canada-France-Hawaii Telescope and Subaru Telescope), and mid-IR (Spitzer/IRAC) imaging. We find excellent agreement with publicly available spectroscopic redshifts, with Delta *s z /(1 + z) ~ 1%-2% for ~4000 galaxies at z = 0-3. The NMBS catalogs contain ~13,000 galaxies at z > 1.5 with accurate photometric redshifts and rest-frame colors. Due to the increased spectral resolution obtained with the five NIR medium-band filters, the median 68% confidence intervals of the photometric redshifts of both quiescent and star-forming galaxies are a factor of about two times smaller when comparing catalogs with medium-band NIR photometry to NIR broadband photometry. We show evidence for a clear bimodal color distribution between quiescent and star-forming galaxies that persists to z ~ 3, a higher redshift than has been probed so far.
•Pd/TNP@SC with electric field and far-infrared radiation of tourmaline is prepared.•Pd/TNP@SC owns great FAEO activity and CO-tolerance than that of TNP-free catalyst.•Tourmaline leads to small Pd ...NPs, weak Pd-O bond, and easy molecule migration.•Dissociated OHadfrom water by electric field spontaneously convert COad into CO2.•Interaction between pPd NPs and OHad at the positive pole of TNP/SC is a key factor.
Palladium is the most effective catalyst with high initial activity for formic acid electrooxidation (FAEO) in direct formic acid fuel cells (DFAFCs), but the low performance of DFAFC comparing to H2-PEMFC and the accumulation of COad poisoning species on palladium restrict the commercialization of DFAFC. Herein, a novel and efficient FAEO catalyst, tourmaline modified Pd (Pd/TNP@SC) are prepared. A class of core@shell structured carbon coated tourmaline (TNP@SC) are equipped as the catalyst support to efficiently utilize the spontaneous polarization-induced electric field and far-infrared radiation of tourmaline for FAEO reaction. Physical and electrochemical measurements suggest that the existence of electric field and far-infrared radiation of tourmaline promote synthesizing smaller Pd nanoparticles, weakening the Pd-O bond, increasing molecular vibration and migration rate, and dissociating water molecules into OHad to spontaneously convert COad into CO2. Even under potentials applied higher than 0.3 V (vs. Ag/AgCl), Pd/TNP@SC catalysts still have high FAEO activity. Among all the Pd/TNP@SC catalysts investigated in this study, Pd/TNP@SC-800 owns the strongest electric field and far-infrared radiation, exhibits the best activity for FAEO, which is 3.1 times higher than that of tourmaline-free catalyst (Pd/SC)), and excellent CO-tolerance during FAEO reaction. This work provides an effective catalyst design strategy for FAEO.
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The experiments of contact ultrasound-assisted far-infrared radiation (FIR) drying on potato slices were conducted to investigate the effects of ultrasonic power on drying characteristics and quality ...properties. The results showed that contact ultrasound was helpful for accelerating mass transfer of the samples, and the improvement of ultrasonic power could significantly shorten drying time. The ultrasonic reinforcement effect on drying rate declined along with the decrease in moisture content.
D
eff
values were within 1.15 × 10
−10
and 1.96 × 10
−10
m
2
/s, and improved with an increase in ultrasound power. Compared with FIR dried ones, more and larger pore size of microcapillaries in the samples’ tissue structure could be observed with contact ultrasound application, and higher ultrasonic power produced more microtunnels. Contact ultrasound in FIR drying could reduce the color difference of dried potato slices, and decrease the hardness and brittleness values. Higher TPC and TFC could be achieved as ultrasonic power increased.
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.
Abstract We present 75 near-infrared (NIR; 0.8−2.5 μ m) spectra of 34 stripped-envelope core-collapse supernovae (SESNe) obtained by the Carnegie Supernova Project-II (CSP-II), encompassing optical ...spectroscopic Types IIb, Ib, Ic, and Ic-BL. The spectra range in phase from pre-maximum to 80 days past maximum. This unique data set constitutes the largest NIR spectroscopic sample of SESNe to date. NIR spectroscopy provides observables with additional information that is not available in the optical. Specifically, the NIR contains the strong lines of He i and allows a more detailed look at whether Type Ic supernovae are completely stripped of their outer He layer. The NIR spectra of SESNe have broad similarities, but closer examination through statistical means reveals a strong dichotomy between NIR “He-rich” and “He-poor” SNe. These NIR subgroups correspond almost perfectly to the optical IIb/Ib and Ic/Ic-BL types, respectively. The largest difference between the two groups is observed in the 2 μ m region, near the He i λ 2.0581 μ m line. The division between the two groups is not an arbitrary one along a continuous sequence. Early spectra of He-rich SESNe show much stronger He i λ 2.0581 μ m absorption compared to the He-poor group, but with a wide range of profile shapes. The same line also provides evidence for trace amounts of He in half of our SNe in the He-poor group.
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
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