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Water decreases the brightness of the peroxyoxalate chemiluminescence partially due to the hydrolysis of the oxalate reagent. Here, we show that encapsulation of an oxalate ester and the fluorescent activator in microspheres of cellulose esters increases the emission intensity 30 times compared to the same reaction in water without encapsulation, whereas the emission intensity decay rate constants are considerably lower. Emission intensities, rate constants and chemiluminescence quantum yields increase with increasing hydrogen peroxide concentrations. These results expand the potential of application of chemiluminescence, contributing for the development of ultrasensitive analytical methods. [ABSTRACT FROM AUTHOR]

This article is aimed at understanding of the complex design of metalorganic chemical vapour deposition ‐grown InGaN‐based red light‐emitting diode (LED) structure. The contribution of different elements of red LED structure to the stress distribution and threading dislocation density (TDD) evolution is theoretically investigated. For this purpose a self‐consistent modeling of the structure growth process is used, taking into account stress‐modulated indium incorporation, mismatch stress relaxation by threading dislocations and V‐pits, and nucleation of new threading dislocations. The simulation results, consisting of composition, stress, and TDD profiles, are then utilized for modeling of device operation, which allows to analyze contribution of different elements to the heterostructure operation. [ABSTRACT FROM AUTHOR]

The paper reports the results of study of composition, emission, and optical properties of polycrystalline W and Mo samples implanted with Ba+ ions and coated with submonolayer Ba atoms by applying Auger electron spectroscopy, secondary electron emission coefficient s technique, as well as the photoelectron quantum yield Y. The experimental part was carried out by using the instrumentation and under vacuum Р ≈ 10-6 Pa. It is shown that during the implantation of Ba ions in the surface layers of refractory metals, a mechanical mixture of the W + Ba and Mo-Ba types is formed. It has been established that the values of the coefficient of secondary electron emission s and the quantum yield of photoelectrons Y at the same value of the work function еφ in the case of implantation of Ba+ ions are much larger than in the case of deposition of atoms. The obtained experimental results are substantiated by theoretical calculations.

The paper reports the results of study of composition, emission, and optical properties of polycrystalline W and Mo samples implanted with Ba+ ions and coated with submonolayer Ba atoms by applying Auger electron spectroscopy, secondary electron emission coefficient σ technique, as well as the photoelectron quantum yield Y. The experimental part was carried out by using the instrumentation and under vacuum Р ≈ 10-6 Pa. It is shown that during the implantation of Ba ions in the surface layers of refractory metals, a mechanical mixture of the W + Ba and Mo-Ba types is formed. It has been established that the values of the coefficient of secondary electron emission σ and the quantum yield of photoelectrons Y at the same value of the work function еφ in the case of implantation of Ba+ ions are much larger than in the case of deposition of atoms. The obtained experimental results are substantiated by theoretical calculations. [ABSTRACT FROM AUTHOR]

The metal–dielectric cermet (metal‐rich) material is utilized for turning the dispersion properties of surface plasmon in GaN‐light‐emitting diode. The designed structure contains a cermet layer coated on p‐GaN layer. The optimized ingredients in the cermet material and thickness of the cermet layer are obtained by the simulations. For enhancing the extraction of surface plasmon, the designed structure is further optimized by inserting a layer of low refractive index. The calculated results indicate that the Purcell factor in optimized structure is greater than 100 over the emission spectrum and the extraction efficiency of surface plasmon is effectively improved. The photoluminescence (PL) experiment by bottom excitation demonstrates that peaks of PL spectra of the designed and optimized samples are enhanced by 1.6 and 3.4 times, respectively, compared with the sample covered by Ag film. Compared with the naked sample, peaks of PL spectra of bottom pumping of optimized and designed samples are enhanced by 36.3 and 17.2 times, respectively. Peaks of normalized PL spectra by top excitation of optimized and designed samples are enhanced by 29.0 and 9.1 times, respectively. The results of numerical calculations are substantially consistent with the results of PL tests. [ABSTRACT FROM AUTHOR]

In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite–difference time–domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen–vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s− and p−polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s−polarization (57.96%) and the emitter in a nanopillar with p−polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center−based micro− and nano−optics in the future. [ABSTRACT FROM AUTHOR]

In this work, we fabricated a novel spinel‐type phosphor material MgAl2−xGaxO4 doped with Cr3+ by the high‐temperature solid‐state sintering method. The crystal field environment of the spinel was tuned by replacing the Al ions with Ga3+ ions of different concentrations. The cell volume and Dq/B gradient increase from 2.82 to 2.62 with increasing Ga3+ ion doping concentration. This also implies a gradual decrease in the field strength of the crystal. Based on this, the excitation spectra of MgAl1.995−xGaxO4:0.5%Cr3+ phosphors yield a redshift. Increasing the Ga3+ ion doping concentration also improves the emission intensity and thermal stability of the phosphors, and the emission intensity of the Ga3+‐doped phosphors is significantly increased. For a Ga/Al ratio of 1, the thermal stability of the phosphor emission is optimal. The emission intensity at 140°C can maintain 76% of the emission intensity at room temperature, indicating that appropriate Ga3+ ion doping can improve the emission efficiency and thermal stability of the phosphors. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the structural and optical properties of an InGaN-based red micro-LED with a high density of V-shaped pits, offering insights for enhancing emission efficiency. The presence of V-shaped pits is considered advantageous in reducing non-radiative recombination. Furthermore, to systematically investigate the properties of localized states, we conducted temperature-dependent photoluminescence (PL). The results of PL measurements indicate that deep localization in the red double quantum wells can limit carrier escape and improve radiation efficiency. Through a detailed analysis of these results, we extensively investigated the direct impact of epitaxial growth on the efficiency of InGaN red micro-LEDs, thereby laying the foundation for improving efficiency in InGaN-based red micro-LEDs. [ABSTRACT FROM AUTHOR]

In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite–difference time–domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen–vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s− and p−polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s−polarization (57.96%) and the emitter in a nanopillar with p−polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center−based micro− and nano−optics in the future.

To investigate the influence of the number of inlet pipes on the characteristics of flow field and the discharge of solid particles such as bait residue and fish feces, STAR-CCM + was used to analyze the flow of field distribution in a ship-based aquaculture cabin under the conditions of two and four inlet pipes, thus optimizing the inlet pipes of the ship-based aquaculture cabin. Furthermore, a three-phase flow model (solid–liquid–gas) was established to determine the movement characteristics of similar solid particles of residual bait and fish manure in the cabin, while the emission performance of solid particles was analyzed. Finally, the formation of solid particles in the center of the aquaculture cabin was simulated. The simulation results show that the effect of flow field is better with two inlet pipes, and the discharge volume of the bottom outlet has little impact on the emission of solid particles. Findings from this study can serve as a reference and basis for the design and optimization of the aquaculture cabin of an aquaculture vessel. [ABSTRACT FROM AUTHOR]

It is shown that upon the implantation of Ba+ ions in W, a mechanical mixture of [Ba + W] atoms is formed in the surface layer. At an ion energy of E0 = 0.5 keV, the thickness of this layer is ~25–30 Å. Due to a decrease in the work function and an increase in the atomic density of ion-implanted layers, the maximum coefficient of secondary-electron emission σmax and the photoelectron quantum yield Y increase significantly. When the [Ba + W] system is heated to T = 900 K, the formation of a chemical bond between Ba and W atoms is not observed. In the case of the implantation of Ba+ ions in WO2, compounds of the W–O, Ba–O, and Ba–O–W types are formed in the surface layer. In this case, the growth of σm and Y is explained only by a decrease in the work function of the surface. [ABSTRACT FROM AUTHOR]

Sulfur-oxide (SO X) emissions from ports are a crucial environmental concern due to their impact on air quality. European ports, particularly in sulfur emission control areas (ECAs), are under a stringent regulation to reduce SO X emissions; thus, evaluating emission efficiencies and identifying improvement pathways for ports are crucial for developing effective environmental strategies. The research employs a Context-dependent Slack-Based Measure Data Envelopment Analysis (SBM-DEA) model to evaluate the SO X emissions efficiency of 70 major European ports from 2006 to 2018 through introducing multi-layered efficiency frontiers to categorize these ports into the efficiency levels and identify specific improvement targets. The results indicate an overall upward trend in the sulfur oxide emission efficiency of European ports, with significant improvements observed from 2006 to 2012. Ports within the North Sea and Baltic Sea, consistently maintain high emission efficiency due to proactive measures like providing shore power and using low-sulfur fuel. However, more than half of the ports still exhibit low efficiency, primarily due to the lack of effective monitoring systems. The study also provides a detailed improvement pathway for the least efficient ports, demonstrating how incremental enhancements can lead to substantial efficiency gains. • The study uses a Context-dependent SBM-DEA model to evaluate the SOX emissions efficiency of 70 major European ports • Introducing multi-layered efficiency frontiers categorizes ports into the efficiency levels and identify specific improvement targets • Ports within the North Sea and Baltic Sea, maintain high emission efficiency due to proactive measures [ABSTRACT FROM AUTHOR]

Electrification is important for carbon reduction in urban residential buildings. It requires clean regional grids to achieve positive emissions efficiency. In countries where the condition of regional grid decarbonization varies, such as China, an aggressive electrification strategy may increase carbon emissions. However, existing research lacks attention to coordinating building electrification with regional grid decarbonization. This study projects the regional timetable when replacing fuel appliances with electric appliances can reduce carbon emissions from 2022 to 2050. Four strategies with different schedules are designed, of which the carbon emissions are compared under three grid decarbonization scenarios. Results find the following: First, in most regions, replacing gas appliances with high-efficiency electric ones can already reduce carbon emissions, while the transition to direct electric-to-heat appliances takes a long time. Secondly, the current national simultaneous strategy will increase carbon emissions by at least 52MtCO2 when using direct electric-to-heat appliances. The increments come from the Northeast, North, and East. Thirdly, high-efficiency electric appliances can reduce the sensitivity of the emission reduction potential of electrification strategies to the onset time. The study contributes to decision-making processes related to electrification strategies for urban residential buildings, providing a reference for assessing their potential to reduce emissions. • Most regions will take long to reach the carbon emission factor for electric-to-heat appliances to replace gas ones. • Electrification strategies may either reduce or increase carbon emissions. • To prevent carbon lock-in or early retirement of fuel appliances, electrification could be incentivized earlier. • Electrification strategies face many challenges. It is recommended to conduct pilot projects before initiating action. [ABSTRACT FROM AUTHOR]

To investigate the effect of co-doping on the optical properties of Eu(2+/3+) doped in Ba0.98SiO3:0.02Eu, the series of Ba0.96SiO3:0.02Eu, 0.02R+/3+ (R+ = Li+, K+ or Na+, R3+ = La3+ or Y3+) phosphors were synthesized using a solid-state reaction method. The excitation efficiency due to the charge transfer band (CTB) was enhanced via co-doping of R+ and the emission intensity due to Eu3+ was thus increased by 3.7 times compared with that of the single-doped Ba0.98SiO3:0.02Eu3+. However, the co-doping of R+ does not increase the emission intensity of Eu3+ via the direct 7F0→5L6 excitation of Eu3+, but rather decreases it. On the other hand, the emission intensities due to Eu2+ were decreased via the co-doping of R+ but increased via the co-doping of La3+. The present work reveals that the optical properties of Eu3+ or Eu2+ doped in BaSiO3 depend not on the charge state (+ or 3+) of the co-doped ions, but on the co-doped element itself. [ABSTRACT FROM AUTHOR]

Considering the high impact of urbanization on climate change, it is pertinent to explore the nexus between household carbon emissions (HCEs), urban population size and population density in Indian cities so as to test whether larger or denser cities are carbon emission efficient. In this study, the statistical significance and variations of mean per capita HCEs are evaluated across six classes of Indian cities classified on the basis of population size and, five classes based on population density by conducting analysis of variance followed by post-hoc test. The results clearly demonstrate that larger or denser cities are not emission efficient. In addition to that, by revisiting scaling laws, it is analytically deducted that for a city to qualify for exhibiting simultaneous emission efficiency in relation to population size and density, population size exponent (α) must lie between 0 and 0.5 and the value of density exponent (β) must be greater than α and lower than unity. By quantifying, comparing and tracking carbon emission efficiencies of cities based on population size and density parameters, the findings of this study potentially provide new insights to policy makers towards approaching the highly ambitious decarbonization goals stated in India's Panchamrit commitment, 2070. • Emission efficiency index covering all Indian cities across six classes. • Larger or denser cities in India are not emission efficient. • Population size exponent (α) must lie between 0 and 0.5 for emission efficiency. • Density exponent (β) must lie between (α) and unity for emission efficient cities. [ABSTRACT FROM AUTHOR]

To investigate the influence of the number of inlet pipes on the characteristics of flow field and the discharge of solid particles such as bait residue and fish feces, STAR-CCM + was used to analyze the flow of field distribution in a ship-based aquaculture cabin under the conditions of two and four inlet pipes, thus optimizing the inlet pipes of the ship-based aquaculture cabin. Furthermore, a three-phase flow model (solid–liquid–gas) was established to determine the movement characteristics of similar solid particles of residual bait and fish manure in the cabin, while the emission performance of solid particles was analyzed. Finally, the formation of solid particles in the center of the aquaculture cabin was simulated. The simulation results show that the effect of flow field is better with two inlet pipes, and the discharge volume of the bottom outlet has little impact on the emission of solid particles. Findings from this study can serve as a reference and basis for the design and optimization of the aquaculture cabin of an aquaculture vessel.

To investigate the effect of co-doping on the optical properties of Eu(2+/3+) doped in Ba0.98SiO3:0.02Eu, the series of Ba0.96SiO3:0.02Eu, 0.02R+/3+ (R+ = Li+, K+ or Na+, R3+ = La3+ or Y3+) phosphors were synthesized using a solid-state reaction method. The excitation efficiency due to the charge transfer band (CTB) was enhanced via co-doping of R+ and the emission intensity due to Eu3+ was thus increased by 3.7 times compared with that of the single-doped Ba0.98SiO3:0.02Eu3+. However, the co-doping of R+ does not increase the emission intensity of Eu3+ via the direct 7F0→5L6 excitation of Eu3+, but rather decreases it. On the other hand, the emission intensities due to Eu2+ were decreased via the co-doping of R+ but increased via the co-doping of La3+. The present work reveals that the optical properties of Eu3+ or Eu2+ doped in BaSiO3 depend not on the charge state (+ or 3+) of the co-doped ions, but on the co-doped element itself.

We have studied the composition, electron emission, and optical properties of CdS single crystals covered by a surface film of adsorbed Ba atoms with thickness Θ from 0.5 to 5 monolayers (ML). It is established that, as Θ increases up to 1 ML, yield depth λ of true secondary electrons (and photoelectrons) in the emission zone exhibits significant growth, which is explained by decreasing work function of the material surface. The further increase in Θ is accompanied by a decrease in both λ and photocurrent intensity values. It is found that no significant mutual diffusion of atoms at the Ba–CdS interface takes place at room temperature. Upon heating to T = 700 K, sulfur atoms exhibit intense diffusion into the Ba film and form a surface compound of the Ba2S type. [ABSTRACT FROM AUTHOR]

[Display omitted] • Peroxyoxalate chemiluminescence can be conveniently performed in aqueous media with reagents incapsulated in cellulose microspheres. • Chemiluminescence kinetics are considerably slower than in homogenous aqueous media and emission intensities are higher. • Chemiluminescence emission efficiencies are two orders of magnitudes higher in the organized media than in aqueous condition. • The system might be utilized in analytical and bioanalytical assays in aqueous media. The sustainable application of chemiluminescence technology benefits from the development of efficient chemiluminescent reactions in water. The peroxyoxalate reaction is used in self-illuminating devices, such as light sticks, and has high emission quantum yields in organic solvents. Here, we demonstrate that by encapsulating bis(2,4,6-trichlorophenyl) oxalate and the dye rubrene within microspheres of cellulose carboxylic esters, the chemiluminescence quantum efficiency of the peroxyoxalate reaction in water can be enhanced by two orders of magnitude. These findings indicate that the encapsulation of reagents of the peroxyoxalate system holds promise for its advantageous application in analytical and bioanalytical assays conducted in aqueous media. [ABSTRACT FROM AUTHOR]

Rhenium–osmium geochronometry for samples with low Re and complex matrices requires improved Re extraction methods. Here, we investigate plausible controls on efficiency and efficacy of Re extraction during our anion resin bead purification. Four different protocols are compared, each isolating a single variable to test. Rhenium concentrations for solutions at each step of each protocol document differences in chemical recovery/yield. The negative‐thermal ionisation mass spectrometry (N‐TIMS) signal intensity serves as a proxy for Re yield and purity. These data document correlations between the N‐TIMS signal intensity and (a) the duration of anion resin bead conditioning prior to loading with Re‐bearing solution, and (b) both duration and strength of nitric acid used during rinsing of the Re‐loaded anion resin bead. The optimal protocol improved Re signal intensity around fourteen times compared with our current Re extraction protocol, an aggregate of 2.4 times improvement in chemical recovery (yield) and 5.8 times improvement in emission efficiency (purity). Repeated N‐TIMS isotopic measurements on our in‐house Re standard solution (1407) verify that our optimal protocol‐3 does not fractionate Re isotopes. The improved anion resin bead method considerably lowers the Re detection limit and allows Re‐Os isotopic analysis of picogram‐level Re hosted in geological samples with complex matrices. [ABSTRACT FROM AUTHOR]

In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite-difference time-domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen-vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s- and p-polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s-polarization (57.96%) and the emitter in a nanopillar with p-polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center-based micro- and nano-optics in the future.

Understanding the spatial variability of CO 2 emissions among and within cities and its driving factors is a prerequisite for emission reductions. Using 10 × 10 km national grid emission data (circa 2007), we quantified the spatial distribution of total CO 2 emissions and emission efficiency of Chinese cities at the prefectural city scale. The emission efficiency was measured according to the emission intensity, CO 2 emissions per capita, residential CO 2 emissions per capita and industrial CO 2 emissions per unit area. We found substantial variability in the total CO 2 emissions among cities ranging from <0.1 to 214.3 million tons. High total CO 2 emissions were mostly concentrated in northern, eastern and northeastern China. An overall analysis of the total CO 2 emissions and emission intensity revealed that 75% of the cities in northern China had higher total emissions and lower efficiencies than the national average, and these cities shall be the main targeted cities for CO 2 emissions reduction and emission intensity improvement. Additionally, urban districts had higher total CO 2 emissions and emissions per capita than their surrounding regions for the majority of the prefectural cities. Four indicators, including the industrial structure, gross domestic product (GDP), total population, and size of the built-up area, were significantly related to the CO 2 emissions and emission efficiency. Industrial structure was the most important driving force. Our results underscore the need to design region- and/or city-specific reduction strategies instead of a one-size-fits-all policy, and provide strategic information to public and private decision makers on controlling total emissions and improving emission efficiency. Unlabelled Image • We mapped city-level CO 2 emissions using 10 × 10 km grid emission data in China. • Cities in Northern China had higher total CO 2 emissions and lower efficiencies. • Urban areas had higher emissions and emission per capita than rural areas. • Industrial structure and built-up area negatively affected emission efficiencies. • GDP had a negative effect on CO 2 emission per unit GDP. [ABSTRACT FROM AUTHOR]

• We have fabricated a new topological insulator of silicon oxide. • The stronger emission in visual region was observed on the topological insulator of silicon oxide. • It is fundamentally responsible for creating extended edge states. The stable form of silicon takes on the structure of diamond (cF8, d -Si) which is an indirect bandgap semiconductor. Its emission efficiency is very lower (about 10−5) that prevents it from being considered as an ext-generation platform for semiconductor technologies [1–5]. Here, we report the formation of a new topological insulator of silicon oxide produced by nanosecond pulsed laser, using a novel two-step preparation methodology, which has a good emission. First, the amorphous silicon layer was fabricated by nanosecond pulsed laser etching and deposition at oxygen environment, then the topological insulator of silicon oxide was prepared by annealing at 1000°C for suitable time. The stronger emission in visual region was observed in photoluminescence (PL) measurement on the topological insulator doped with lower oxygen density, where its external quantum efficiency in emission rises over 20% by four orders than that on pure silicon. It is interesting that the quantum platform of emission has been founded in the evolution curve of PL intensity with change of excitation power. The physical model shows that the higher emission efficiency is originated from the special electronic properties in the new topological insulator of silicon oxide, which is fundamentally responsible for creating extended edge states. The topological insulator of silicon oxide will become a new potential material for emission on silicon chip. [ABSTRACT FROM AUTHOR]

Abstract A novel polysilicon light emitting device (LED) was realized in a standard complementary metal oxide semiconductor (CMOS) process that is based on a p-n junction reverse bias configuration. This LED can emit visible light based on the reverse bias p-n junctions in the dark. The central emitting doped structure element of this LED is n+-p-n+-p-n+ stacked layout, which is similar to two reverse bias p-n junctions and two forward bias p-n junctions connected in series. The device mechanism for the visible light emitting process is defined by means of an avalanche breakdown process that occurs between the highly doped n+ region and the lightly doped p region in the reverse bias p-n junctions. By using hot carriers generated in avalanche process, the emission spectrum from the device exhibits a wide spectrum whose wavelength range is from 400 nm to 900 nm at an operating voltage of 16 V. We compare the designed light intensities at the different wavelengths in other to obtain the dependency of the light emission at various wavelengths under different currents conditions. From the experimental observations, and based on the calculation of the quantum efficiency and power conversion efficiencies as related to the light emission, we confirmed that this particular LED has a better efficiency than three-terminal gated diode. The silicon light source could find some applications in on-chip optical interconnect and in electro-optical conversions in future all-silicon integrated photonic circuitry. Highlights • A compact silicon light-emitting device that is compatible with standard VLSI processing is presented. • Emission efficiency is further improved by using the new structure. • Output electroluminescence spectrum is analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface micro-structures on GaAs provide thermal radiation at 8.5THz, which has quite different properties from phonon polariton. • Surface Au-GaAs structures enables radiation and absorption control including sub-diffractional effect. • Structural dependence of intensity and line width is scrutinized by experimentally and theoretically. • Short radiative lifetime of LO phonon on the order of 1 ps is expected. • This thermal emission provides future high-efficiency THz sources. Phonon-based tera-Hertz or mid-infrared emission has been investigated because it can be applied to high-efficiency light sources for optical communication and material diagnostics, where thermal energy can be utilized as an energy source of emission. Particularly, nano- and micro-surface structures have been investigated for versatile emission controllability. We present the polarized longitudinal optical (LO) phonon resonant thermal emission of radiation (LORE) peaked at approximately 8.5 THz in a range of 450–650 K from simple surface Au–GaAs–Au micro-stripe structures on undoped (u-) GaAs wafers, where the metal component, which has been avoided for surface phonon polariton (SPhP) emission, is introduced. This LORE is based on electric dipoles formed by coherently oscillating polarization charges on pairs of interfaces and has a feature of structure size or emission direction-independent frequency, which is quite different from the properties of SPhPs. The dependence of emission properties on structural factors and temperature reveals the approximately evenly matched radiative and nonradiative LO-phonon annihilation rates in the local surface field and shows the controllability of emission and absorption balance based on the surface structures. Higher emission efficiency in the higher temperature region is found for structures with narrow emission windows of less than 2 μm. The decrease in the volume occupied by electric dipoles reduces the reabsorption probability of LORE, which shortens the effective radiative lifetime and, resultantly, increases the fraction of the radiative rate in the total annihilation rate. By comparing the emission from a pure graphite wafer, a short LORE mean time interval of approximately 2 ps is found. The background emission subject to Planck's law is significantly reduced particularly in the region of 250–300 cm−1 using emission window widths narrower than 2 μm because of the sub-diffraction phenomenon. [ABSTRACT FROM AUTHOR]

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The three main farm products from Canadian agriculture, i.e., proteins, vegetable oils, and carbohydrates, account for 98% of the land in annual crops in Canada. The intensities and efficiencies of these field crops in relation to their Greenhouse Gas (GHG) emissions were assessed for their value as land use change indicators. To facilitate spatial comparisons, this assessment was carried out at the Ecodistrict (ED) scale. The Unified Livestock Industry and Crop Emissions Estimation System (ULICEES) model was modified to operate at the ED scale, and used to quantify the GHG emission intensity of protein. GHG emissions were also calculated for plant products not used for livestock feed. The livestock GHG emissions and GHG-protein intensities estimated using ED scale inputs to ULICEES were reasonably close to GHG-protein intensities generated by the version of ULICEES driven by provincial scale census data. Carbohydrates were split into two groups, i.e., whether or not they supported livestock. Annual farm product data at 5-year intervals were used to generate GHG emissions from all farm operations. The range of GHG emissions from all farm operations in Western Canada was from 42 to 54 Mt CO2e between in 1991 and 2011, while GHG emissions from livestock ranged from 22 to 34 Mt CO2e over the same period. The Eastern Canadian GHG emissions from all farm operations declined gradually from 24 to 22 Mt CO2e over the period, with most of the eastern GHG emissions being from livestock. Ruminant livestock accounted for most of the livestock GHG emissions, particularly in the west. Provincial scale GHG emission efficiencies of the four farm product groups were assessed on a per-unit of GHG emissions basis for 2006. The most GHG-efficient province for protein was Ontario, whereas the most GHG-efficient province for all three plant products was Saskatchewan. The coastal provinces were the least GHG-efficient sources of all four farm product groups. [ABSTRACT FROM AUTHOR]

In this paper, a new type of light-emitting diodes (LEDs) structure is designed to enhance the light emission efficiency of GaN-based LEDs. The structure mainly includes Ag grating, ITO layer and p-GaN grating. The principle of stimulating the localized surface plasmon to improve the luminous characteristics of the LED by using this structure is discussed. Based on the COMSOL software, the finite element method is used to simulate the LED structure. The normalized radiated powers, the normalized absorbed powers under different wavelength and geometric parameters, and the distribution of the electric field with the particular geometric parameters are obtained. The simulation results show that with a local ITO thickness of 32 nm, an etching depth of 29 nm, a grating period of 510 nm and a duty ratio of 0.5, the emission intensity of the designed GaN-based LED structure has increased by nearly 55 times than the ordinary LED providing a reliable foundation for the development of high-performance GaN-based LEDs. [ABSTRACT FROM AUTHOR]

The unexpected arcs generated in a railgun bore are one of the major issues affecting emission efficiency. To study the impact of such arcs, a series of experiments with the same launch parameters has been conducted. B-dot probes positioned along the length of the launcher provide data for detecting arc formation phenomena and for measuring the armature velocity. In this paper, two sets of typical signals are discussed. The first set of signals is normal, whereas the other is abnormal in terms of the existence of an arc in the bore during launch. The time interval during which the arc generated and the state of the arc are determined from the magnetic induction curves by integrating the B-dot probe signals. Using a fitting analysis, the displacements and velocities of the armatures are obtained, and the energy distribution of each shot is computed. The results indicate that the generation of an arc in the bore causes a hash launch environment and greatly reduces the emission efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Currently, the development of aggregation‐induced emission (AIE) luminogens (AIEgens) has enabled us to “see” never before seen scenery. However, not all AIEgens exhibit the impressive emission efficiency in aggregated states. Moreover, the emission color of AIEgens can be seriously affected when their performance is improved. Therefore, to overcome this limitation, an efficient method is proposed here through the tailored alkyl linkages to greatly improve the emission efficiency of tetraphenylethene (TPE)‐based AIEgens but retain their emission color. Encouragingly, significantly enhanced emission efficiency is achieved with the quantum yield up to 68.19% and 65.20% for BTPE‐C4 and BTPE‐C8, respectively, in contrast to that of TPE (25.32%), demonstrating the proverb that one plus one is much larger than two (1 + 1 >> 2). Interestingly, when alkyl linkages in skeletons are fine‐tuned, self‐assembled nanorods, nanosheets, and nanofibers are successfully achieved for BTPE‐C1, BTPE‐C4, and BTPE‐C8 in tetrahydrofuran and water system. Also, these developed emissive AIEgens not only exhibit impressive response to the environmental stimuli of mechanical force, viscosity, temperature, and light, but can also be used to dynamically monitor and control the phase‐separated morphology in polymeric blends. [ABSTRACT FROM AUTHOR]

Despite the demands of growth, the development of deep-ultraviolet (UV) light-emitting diodes (LEDs) still suffers from the fundamental limits of material defects and the anisotropic optical property of AlGaN multiple quantum-wells (MQWs), resulting in an extremely low emission output. Here, we present a novel approach to address this issue by using a nanoscale hyperbolic metacavity on the deep-UV LED, where the resonant modes of metacavity are excited. An intense plasmon field is consequently feedback to the MQW. This strong resonant mode feedback allows the dipoles of MQW recombine directionally, thereby achieving enhancements of radiative emission rate by a factor of 160 and quantum efficiency by a factor of 3.5. It also shows the capability of metacavity in tailoring the direction of light emission, leading to a 520% increase in total emission intensity and 148% increase in emission extraction. A small divergence angle of 65° of LEDs is therefore demonstrated. Our study clearly shows that the use of metacavity is a promising candidate for the highly-desired efficiency and directivity deep-UV applications, and the metacavity effect can be extended to other nanoscale devices, such as nanolaser, single photon source, nano-biosensor, and nano-antenna. [ABSTRACT FROM AUTHOR]

We propose a type of GaN-LED based on the optimized multilayered lamellar micro-grating. This structure contains a SiO 2 inserted-layer, an Ag grating and a TiO 2 film cover-layer. The Ag grating with optimized parameters is used to enhance the internal quantum efficiency and the transmission simultaneously. The TiO 2 layer with optimized thickness is utilized to improve the transmission through the multilayered structure. The inserted SiO 2 layer suppresses the power loss of Ag grating and further promotes the transmission. The properties of the guided-modes and Purcell effect in this structure are analyzed. The photoluminescence experiment indicates that its peak intensity of top-emission is about 2.2 times greater than the naked sample. [ABSTRACT FROM AUTHOR]

• A new concept metamaterial ring is proposed for enhancing emission efficiency of omnidirectional SH wave source in elastics. • Intrinsic physics of the meta-ring coupling two principles are theorized and numerically confirmed. • The structure of the meta-ring, which serves as a mass-spring model, is explored with two design parameters for its practical adaptability. • Experimental result proves that our meta-ring enhances the emission efficiency of omnidirectional SH wave by over 250%. The intensity of a wave emitted by a transducer affects its performance critically, especially when the emitted wave is omnidirectional. However, the development of omnidirectional transducers lags behind unidirectional ones, despite their practical usability in non-destructive testing. Here, we propose a metamaterial ring ("meta-ring") enhancing the emission efficiency of omnidirectional SH elastic wave sources. Meta-ring is deliberately designed to follow the mechanical behavior of the discrete mass-spring model and is installed independently around the transducer. We interpret the involved physics for emission enhancement using homogenization and elucidate the two principles: a low impedance condition and a Fabry-Perot resonance. In addition, the two key design variables comprising the meta-ring are explored to modulate the practical adaptability. Experiments confirm that the meta-ring increased the emission efficiency of the transducer by over 250%. In that the intensity of an omnidirectional wave decreases inverse squarely in the two-dimensional space, the emission efficiency boosting by the proposed metamaterial concept can be critical in wide-area wave-based non-destructive evaluation. [Display omitted] [ABSTRACT FROM AUTHOR]