Emission Performance Research Articles

Multifunctional Near-Infrared Luminescence Performance of Nd3+ Doped SrSnO3 Phosphor

The phosphors with persistent luminescence in the NIR (near-infrared) region and the NIR-to-NIR Stokes luminescence properties have received considerable attention owing to their inclusive application prospects in the in vivo imaging field. In this paper, Nd3+ doped SrSnO3 phosphors with remarkable NIR emission performance were prepared using a high temperature solid state reaction method; the phase structure, morphology, and luminescence properties were discussed systematically. The SrSnO3 host exhibits broadband NIR emission (800–1300 nm) with absorptions in the near ultraviolet region. Nd3+ ions emerge excellent NIR-to-NIR Stokes luminescence under 808 nm laser excitation, with maximum emission at around ~1068 nm. The concentration-dependent luminescence properties, temperature dependent emission, and the luminescence decay curves of Nd3+ in the SrSnO3 host were also studied. The Nd3+ doped SrSnO3 phosphors exhibit exceptional thermal stability; the integrated emission intensity can retain approximately 66% at 423 K compared to room temperature. Most importantly, NIR persistent luminescence also can be observed for the SrSnO3:Nd3+ samples, which is in the first and second biological windows. A possible mechanism was proposed for the persistent NIR luminescence of Nd3+ based on the thermo-luminescence spectra. Consequently, the exciting results indicate that multifunctional NIR luminescence has been successfully realized in the SrSnO3:Nd3+ phosphors.

Associations between a range of enteric methane emission traits and performance traits in indoor-fed growing cattle.

Despite the multiple definitions currently used to express enteric methane emissions from ruminants, no consensus has been reached on the most appropriate definition. The objective of the present study was to explore alternative trait definitions reflecting animal level differences in enteric methane emissions in growing cattle. It is likely that no single methane trait definition will be best suited to all intended use cases, but at least, knowing the relationships between the different traits may help inform the selection process. The research aimed to understand the complex interrelationships between traditional and novel methane traits and their association with performance traits across multiple breeds and sexes of cattle; also of interest was the extent of variability in daily enteric methane emissions independent of performance traits like feed intake, growth and live-weight. Methane and carbon dioxide data were collected using the Greenfeed system on 939 growing crossbred cattle from a commercial feedlot. Performance traits including feed intake, feeding behavior, liveweight, live animal ultrasound, subjectively scored skeletal and muscular traits, and slaughter data were also available. A total of 13 different methane traits were generated, including (average) daily methane production, five ratio traits and seven residual methane (RMP) traits. The RMP traits were defined as methane production adjusted statistically for different combinations of the performance traits of energy intake, liveweight, average daily gain and carcass weight; terms reflecting systematic effects were also included in the fixed effects linear models. Of the performance traits investigated, liveweight and energy intake individually explained more of the variability in methane production than growth rate or fat. All definitions of RMP were strongly phenotypically correlated with each other (>0.90) as well as with methane production itself (>0.86); the RMP traits were also moderately correlated with the methane ratio traits (>0.57). The dataset included heifers, steers and bulls; bulls were either fed a total mixed ration or ad lib concentrates. When all sexes fed total mixed ration were compared, bulls, on average, emitted the most enteric methane per day of 269.53g, while heifers and steers produced 237.54g and 253.26g, respectively. Breed differences in the methane traits existed, with Limousins, on average, producing the least amount of methane of the breeds investigated. Herefords and Montbéliardes produced 124.50g and 130.77g more methane per day, respectively, than Limousins. The most efficient 10% of test-day records, as defined by daily methane independent of both energy intake and liveweight emitted, on average, 54.60g/d less methane than animals that were average for daily methane independent of both energy intake and liveweight. This equates to 6.5kg less methane production per animal over a 120-day finishing period for the same feed intake and liveweight.

The impact of national land supervision system on urban low-carbon transformation: evidence from China

The land system is a crucial factor influencing urban low-carbon sustainable development. However, previous research has paid little attention to the effects and mechanisms of the national land supervision system (NLSS) on urban low-carbon transformation (ULCT). This study uses China’s routine land inspection as a quasi-natural experiment and examines the impact of NLSS on ULCT using panel data from 283 Chinese cities between 2005 and 2016. The study finds that NLSS significantly promotes ULCT, with a series of robustness checks supporting this conclusion, showing a 1.95% improvement in carbon emission performance in cities under supervision. NLSS mainly facilitates ULCT by improving land use efficiency, upgrading the structural of the service sector, and promoting technological progress. Compared to eastern cities, southern cities, large cities, and non-resource-based cities, NLSS more effectively promotes low-carbon transformation in central and western, northern, small- and medium-sized, and resource-based cities. Additionally, in contrast to cities with high environmental awareness, high marketization levels, high financial development levels, and high fiscal pressure, NLSS more strongly promotes ULCT in cities with lower levels of these factors. Furthermore, NLSS exhibits a significant positive spatial spillover effect in promoting ULCT. In advancing ULCT, NLSS can be synergized with smart city pilot policies and innovative city pilot policies but has not shown synergies with low-carbon city pilot policies.

Coupling coordination relationship between high-quality economic development and carbon emission performance in China: degree measurement, spatio-temporal evolution, and driving factors

Coupling coordination relationship between high-quality economic development and carbon emission performance in China: degree measurement, spatio-temporal evolution, and driving factors

Room-temperature infrared photoluminescence and broadband photodetection characteristics of Ge/GeSi islands on silicon-on-insulator

In this study, molecular beam epitaxial growth of strain-driven three-dimensional self-assembled Ge/GeSi islands on silicon-on-insulator (SOI) substrates, along with their optical and photodetection characteristics, have been demonstrated. The as-grown islands exhibit a bimodal size distribution, consisting of both Ge and GeSi alloy islands, and show significant photoluminescence (PL) emission at room temperature, specifically near optical communication wavelengths. Additionally, these samples were used to fabricate a Ge/GeSi islands/Si nanowire based phototransistor using a typical e-beam lithography process. The fabricated device exhibited broadband photoresponse characteristics, spanning a wide wavelength range (300-1600 nm) coupled with superior photodetection characteristics and relatively low dark current (∼ tens of pA). The remarkable photoresponsivity of the fabricated device, with a peak value of ∼11.4 A W-1(λ∼ 900 nm) in the near-infrared region and ∼1.36 A W-1(λ∼ 1500 nm) in the short-wave infrared (SWIR) region, is a direct result of the photoconductive gain exceeding unity. The room-temperature optical emission and outstanding photodetection performance, covering a wide spectral range from the visible to the SWIR region, showcased by the single layer of Ge/GeSi islands on SOI substrate, highlight their potential towards advanced applications in broadband infrared Si-photonics and imaging. These capabilities make them highly promising for cutting-edge applications compatible with complementary metal-oxide-semiconductor technology.

Luminescence Patterns on Multimillimeter Single-Crystal MAPbBr3 Microplatelets via Thermal Ablation Effects.

The single crystal distinguishes itself as the most outstanding representative of excellent optoelectronic performance among perovskite semiconductors due to its exceptional charge carrier properties, extraordinary optophysics, precise structural geometries, and superior material stabilities. However, it exhibits mediocre performance in light emission, which can be attributed to its excessive carrier diffusion lengths and extremely low recombination rates. To address this challenge, this study puts forward a controllable high-temperature annealing treatment strategy concentrating on multimillimeter-scale MAPbBr3 micrometer-thick platelet single crystals (MPSCs). Through the utilization of thermal ablation effects to convert the surface monocrystalline lattices into polycrystalline perovskite nanocrystals (PNCs) with a remarkably increased specific surface area, the fluorescence intensity arising from the rapid recombination of free carriers on the PNC surface is enhanced by 320 times compared to the pristine MPSC surface. These PNCs produced through surface annealing, with the characteristic of loose adhesion to surfaces, can be mechanically wiped away and regenerated in situ via reannealing the residual MAPbBr3 MPSCs, guaranteeing high intensity, durability, and standard geometric fluorescence. Moreover, by regulating the surface distributions of thermal ablation effects and carrying out embossing annealing treatment or laser direct writing, we can design and fabricate relatively complex, high-contrast (255×), and clearly resolved fluorescence patterns on MPSC surfaces.

Synthesis, Structural Analysis and Bright Emission Performance of a New Family of 3D Lanthanide Coordination Polymers Based on 1,3‐phenylenediacetic Acid

AbstractA novel series of isostructural lanthanide coordination polymers with the general formula [Ln2(PDA)3(DMF)2] (where Ln3+= La, Nd, Pr, Tb, Sm and Eu, DMF= N,N’‐dimethylformamide and PDA =1,3‐phenylenediacetate) were hydrothermally synthesized and further characterized by vibrational spectroscopy, thermal analysis, scanning electron microscopy (SEM), energy dispersive X‐ray (EDX) analysis, and powder and single‐crystal X‐ray diffraction techniques. In addition, from the crystallographic data, it was possible to determine the topology of the structure, finding that the network consists of 5‐connected nodes with topological type: nov; 5/4/o8 and point symbol (44.66). To study the luminescence properties regarding potential energy transfers among the building blocks, lanthanum‐based samples doped with Tb (III) and Eu (III) (1 %, 2 %, 5 % and 10 %) were analyzed in solid state. Upon ligand sensitization, 4 f transitions could be observed confirming an “antenna effect” of the PDA ligand. These new compounds are potential materials for the construction of photoluminiscent devices.

Supression of shielding effect of large area field emitter cathode in radio frequency gun environment

Abstract Utilisation of large area field emitters (LAFE) cathodes for rf gun injector hold promise for delivering compact, high power and high brightness electron beam for advanced accelerator technologies. LAFEs subjected to DC electric fields posses significant challenges due to the shielding effect which restricts emission from central emitters and decreases the overall current density. Mitigating the shielding effect of LAFE in rf gun environment is essential for meeting the desired beam quality requirement in an accelerator. The current distribution of LAFE under DC conditions depend on its various geometrical parameters such as emitter height, inter-emitter distance, aspect ratio, number of emitters. Additionally, in rf gunsetup, LAFEs are subjected to variable macroscopic electric field at different emitter position which can potentially alter the current distribution compared to DC fields. In this work, we have systematically studied the shielding effect properties of LAFE in rf gun environment under the influence of various LAFE parameters. A semi-analytical approachhas been adopted to estimate the current distribution which combines the analytically calculated field enhancement factor (γ) and numerically calculated applied rf field values. This new methodology was first validated using COMSOL simulation and then employed for field emission performance estimation of a LAFE cathode integrated in a½ cell S-band (2856 MHz) rf gun. The simulation results reveals that under favourable conditions, a Gaussian spatial distribution of beam can be obtained from LAFE thus countering the shielding effect typical in DC fields. By optimizing the LAFE parameters, the desired current and beam distribution pattern can be achieved. This study highlights the adoption of a promising approach for designing LAFE cathodes suitable for rf gun which can lead to advancement of field emission technologies for accelerator-related applications.

Pengungkapan Kinerja Lingkungan Emisi Karbon Pada Perusahaan Farmasi Proper dan Non Proper di Indonesia

This research aims to determine the differences between PROFER and Non-PROFER regarding the disclosure of the carbon emissions environmental performance of pharmaceutical companies listed on the IDX for the 2019-2023 period. The population in this research is pharmaceutical companies listed on the Indonesia Stock Exchange and having PROFER and Non-PROFER ratings in 2019-2023. Sampling was carried out using the Purposive Sampling method. The research results show that there is no market reaction to mergers and acquisitions which is indicated by the value of no difference in the disclosure of environmental performance of carbon emissions produced by PROFER and NON PROFER pharmaceutical companies on the IDX for the 2019-2023 period.

Transforming wastewater-derived algae biodiesel with ammonium hydroxide emulsion for enhanced energy efficiency and emission reduction

The growing demand for sustainable energy has prompted a search for alternative fuels, with microalgae-based biodiesel emerging as a promising option. However, improving its energy efficiency and minimizing environmental impacts remain key challenges. This study presents a novel approach by integrating wastewater-derived algae cultivation with ammonium hydroxide emulsion to enhance biodiesel performance. Chlorella vulgaris microalgae were grown in a medium of diluted human urine, where nutrient removal efficiency was evaluated, and biooil was extracted via solvent extraction. The resulting biodiesel was analyzed for elemental, chemical, and physicochemical properties. A 30 % blend of Chlorella vulgaris algae biodiesel (CVAB) with normal diesel fuel (NDF) was prepared. To further boost energy efficiency and emissions performance, ammonium hydroxide emulsion was added at concentrations of 5 % and 10 %. Results confirmed that wastewater-sourced algae cultivation is a viable method for sustainable biodiesel production. While CVAB's combustion characteristics were similar to NDF's, it exhibited a 7 % decrease in brake thermal efficiency and a 5 % increase in nitrogen oxide emissions. The addition of ammonium hydroxide emulsion notably improved both energy efficiency and emission profiles. This study highlights a breakthrough in using ammonium hydroxide emulsion to enhance algae biodiesel, making it a more competitive alternative to fossil fuels. Economically, this approach offers a dual advantage: utilizing low-cost wastewater for biodiesel production while improving fuel performance and reducing emissions.

Impacts of Environmental Conditions on Thermal, Emissions and Economic Performance of Gas Turbine Using Different Types of Fuels: An Experimental Investigation

Gas turbine has been used widely for electrical power generation based on simple cycle system. However, the relatively low thermal efficiency engages the researchers in investigating possible methods to enhance gas turbine performance. In the current study, three different types of fuels were used (crude oil, light oil, and natural gas) to operate the gas power plant in Qayyara, Mosul, Iraq and to evaluate the plant's performance, environmental impact and economic cost. The Aspen Husys package was used for simulation based on data recorded by the control department. Results showed that the software applied was highly valid. The external environmental temperature influenced the performance and efficiency of the station significantly with maximum values obtained for winter by 114MW and thermal efficiency of 32.02% for natural. The emissions of CO2, SO2, and NOX gases are decreased, whereas CO emission is increased when the temperature of the external environment is raised with fewer emissions obtained for natural gas. The cost of three fuels in (summer) is the highest among the four months, with the higher cost for light fuel by 68.2 Iraqi diners/kiloWatt.hour. Therefore, light fuel cannot be used for the permanent operation of gas turbines, and natural gas fuel gives better performance and lower emissions than the other two types of fuels.

Self-assembly aggregation-induced emission from Eu (III) complexes with o-hydroxy-benzophenone ligands

In this work, europium (III) complexes were synthesized by using different o-hydroxy-benzophenone ligands, namely 2-hydroxy-4-octyloxybenzophenone (HL1), 4-allyloxy-2-hydroxybenzophenone (HL2) and 2-hydroxy-4-methoxybenzophenone (HL3). The structures and optical properties of the EuIII complexes E1, E2 and E3 were characterized by elemental analysis, infrared/fluorescence spectroscopy and mass spectrometry. The aggregation-induced emission properties from E1, E2 and E3 were systematically investigated in the acetone/water binary mixtures. At the same time, the corresponding agglomeration behavior and self-assembly structures in the EuIII complex system was confirmed through scanning electron microscopy. Excellent luminescent performance was illustrated in sample of E1 (the luminescence quantum yield of 21.36% in solid state) which should be attributed to the aggregation-induced emission from better self-assembly behavior with longer carbon chain in ligand. The results of ultraviolet aging resistance from E1 reveal that the self-assembly behavior could not only improve the aggregation-induced emission performance, but also enhance the photostability of EuIII complex compared with the traditional β-diketone EuIII complex. This discovery may provide a facile strategy to design and prepare more promising rare earth complexes with good luminescence properties and strong photostability for application in solid state.

The mechanism of strontium doping to enhancing the electron emission performance of barium-tungsten cathode

The mechanism of strontium doping to enhancing the electron emission performance of barium-tungsten cathode

Does artificial intelligence improve enterprise carbon emission performance? Evidence from an intelligent transformation policy in China

Does artificial intelligence improve enterprise carbon emission performance? Evidence from an intelligent transformation policy in China

Research on the Characteristics of High-Performance Textured Ceramic Materials and Their Application in Composite Rod Transducers

Recently, textured piezoelectric ceramics have become a hot topic in the field of piezoelectric materials. Due to their high cost-effectiveness, textured ceramics are expected to be the material of choice for the next generation of acoustic transducers. In this study, we investigated the coercive field (Ec), piezoelectric constant (d33), and dielectric constant (ε33) of textured PIN-PSN-PT ceramics under different torques, in response to the demand for the development of composite rod transducer technology for transmitting and receiving. Based on the obtained data, a wideband composite rod transducer was designed and fabricated using textured PIN-PSN-PT ceramics with high performance. Compared with conventional PZT piezoelectric ceramic transducers of the same size, the wideband composite rod transducer made with textured ceramics extends the frequency band to a lower frequency of 6.5 kHz, improves the emission performance by 2 dB, and enhances the reception performance by 2 dB. Compared with conventional PZT piezoelectric ceramics in the same frequency band, the acoustic performance is comparable, but there is a volume reduction of 59.23% and a weight reduction of 49.7%, solving the technical bottleneck of developing composite rod transducers that are miniaturized and lightweight. The research results of this study have important reference value for the engineering application of textured ceramic materials in acoustic transducers.

Does advanced human capital structure improve carbon emission performance in China? Empirical research from a spatial spillover perspective

Facilitating coordination between economic growth and carbon mitigation is vital for the sustainability of human society. Identifying the driving factors of Carbon emission performance (CEP) is crucial for its improvement. Nevertheless, empirical research on the relationship between advanced human capital structure (AHCS) and CEP remains scarce. This study analyzes the impact of AHCS on CEP utilizing a dataset covering 30 Chinese provinces from 2006 to 2021. First, we construct a global epsilon-based measure (EBM) model with undesired output to accurately measure the multi-period CEP for Chinese provinces. Next, we evaluate the level of AHCS from the perspective of dynamic evolution. Subsequently, a spatial Durbin model (SDM) is employed to examine the spatial spillover effects of AHCS on CEP. The results illustrate that CEP exhibits significant positive spatial spillover effects across provinces. Additionally, AHCS has a direct and significant positive impact on local CEP and can indirectly enhance CEP in neighboring regions through spillover effects, although the impact varies across different regions. The impact mechanism analysis indicates that AHCS enhances CEP via technological advancement, industrial structure upgrading (ISU), and energy efficiency improvement, despite the asymmetric effects observed between local and neighboring provinces. Therefore, shaping a favorable educational environment to optimize the human capital structure is critical for the improvement of CEP. In addition, promoting resource sharing and technology exchange through regional cooperation is essential for China’s low-carbon transition development.

Operation parameters investigation on combustion and emission of a non-road diesel engine based on orthogonal experiment design at different altitudes

For improving the combustion and emission performance of engines operating at high altitude regions, a two OED optimization method was proposed. The influence of each factor on the target was analyzed and discussed through a primary OED. Based on the primary OED test, factors with less influence were excluded to reduce factors in the secondary OED test. The results showed that low intake pressure led to poor spray mixing, prolonged ignition delay, and incomplete combustion, resulting in deteriorated power output, fuel economy, and emission characteristics. After two OED optimizations, The NOx emissions increased significantly by 40.5 % and 122.5 % in the first and second optimization, respectively, however, the ISFC decreased by 13.4 % and 25.2 %, and CO decreased by 13.0 % and 25.2 % in the first and second optimization, respectively, as well as ultra-low carbon smoke emissions was achieved. The related theories and methods' advantage can be extended to engineering applications and has good practical value.

Measuring carbon emission performance in China's energy market: Evidence from improved non-radial directional distance function data envelopment analysis

The most complex challenge facing the energy market is identifying effective solutions to reduce CO2 emissions (CEs) and enhance environmental performance (EP). Coal production within the power sector is the primary source of these emissions. In this study, we developed a novel linear programming model that accounts for undesirable outputs to assess the EP of 15 power enterprises in eastern China from 2016 to 2020. In addition, we employed a global non-radial Malmquist-Luenberger productivity index (GNML) to analyse the mechanisms influencing changes in efficiency among these enterprises. Our findings indicate that, while the EP of the power industry in eastern China improved, it remains at a relatively low level and exhibits instability. Moreover, technological efficiency (TE) and scale efficiency (SE) play a significant role in determining production efficiency within the sector. Therefore, it is essential for industry managers to implement standardized production management regulations, enhance technological development and scale investments, and strengthen control over unintended emissions that could facilitate energy transition.

The Hidden Mechanism: Excited-State Proton-Electron Pair Transfer in Metal Nanocluster Emission.

Comprehending the underlying factors that govern photoluminescence (PL) in metal nanoclusters (NCs) under physiological conditions remains a highly intriguing and unresolved challenge, particularly for their biomedical applications. In this study, we evaluate the critical role of excited-state proton-coupled electron transfer in the emission of metal NCs. Our findings demonstrate that hydronium ion (H3O+) binding can trigger a nonlinear, pH-dependent excited-state concerted electron proton transfer (CEPT) reaction. This involves simultaneous electron transfer from the Au(0) core to the Au(I)-ATT (ATT denotes 6-aza-2-thiothymidine) surface and proton transfer from H3O+ to the ATT ligand in a single step, greatly promoting vibrations and rotations of the Au(I)-ATT surface, resulting in substantial PL quenching of Au10(ATT)6 NCs. Further analyses show that the unique CEPT dynamics are strongly influenced by the opposing effects of increased reorganization energy and a larger pre-exponential factor on the electron transfer rate. Moreover, the proposed excited-state CEPT process is found to be prevalent in core-shell relaxation metal NCs, such as Au25(SR)18 (SR denotes thiolate) NCs, and serves as an important factor in limiting their PL emission. By simply controlling the pKa of the ligands, the emission performance of Au25(SR)18 can be easily regulated in physiological environments.

The effect of magnetic nanofilm morphology on spintronic terahertz emission performance

Femtosecond laser-driven spintronic terahertz (THz) emitters based on magnetic nanofilms are poised to be the next-generation mainstream THz radiation devices due to their low cost, high performance, ultra-broadband, and easy integration. The radiation performance of spintronic THz emitters is related to the material characteristics, heterostructure interfaces, pump laser, and magnetic field intensity. Additionally, the THz emission performance is greatly reliant on the material surface morphology. Here, we employed ultrafast THz scattering-type scanning near-field optical microscopy with nanoscale spatial resolution to obtain the static THz scattering nano-imaging of ferromagnetic/antiferromagnetic heterostructures (W/Co20Fe60B20/IrMn3). We established the relationship between surface morphology and THz scattering intensity. Utilizing laser-induced THz emission technology, we achieve injection and detection of nanoscale ultrafast spin current without the external magnetic field. The strong consistency of the THz emission nanoscopy with the atomic force microscopy topography demonstrates that the sample surface morphology is critical to the THz radiation performance. This study serves as a valuable reference for the further optimization of spintronic THz emitters and promotes the development of high-performance, strong-field spintronic THz sources.