Emission Intensity Research Articles

Chemiluminescence during the high-temperature pyrolysis and oxidation of ammonia

Chemiluminescent emissions from NH2*, NH*, NO*, and OH* during the pyrolysis and oxidation of ammonia (NH3) are quantitatively characterized to gain insight into their reaction mechanisms. Time profiles of light emitted from high-temperature reactions of NH3/Ar and NH3/O2/Ar mixtures have been measured behind reflected shock waves at temperatures of 2300–2600 K and pressures of 1.6–1.9 bar in a high-repetition-rate shock tube. The emission intensities have been calibrated based on the well-characterized OH* chemiluminescence in a hydrogen-oxygen system and converted to photon emission rates for quantitative comparison with kinetic simulations. A kinetic model describing the pyrolysis and oxidation of ammonia and reactions of excited species has been constructed by combining the reaction mechanisms proposed in recent modeling studies. With only modest updates of the thermodynamic functions and the rate constants for the formation and quenching of excited species, the observed chemiluminescence profiles could be reasonably reproduced, with a few exceptions. The rate of production analysis indicates that NH2* is produced by the reaction of NH3 with H as well as thermal excitation of NH2, that the energy transfer reactions from 3N2 to NH and NO are responsible for the formation of NH* and NO*, respectively, and that the formation of OH* is competitively contributed by the reactions of H with N2O, 3N2 with OH, and NH with NO. Remaining discrepancies between the experiment and modeling are noted, and potential directions for further model improvement are discussed.

The use of infrared thermography as an indicator of methane production in hair sheep.

Infrared thermography may be an alternative technology for measuring the amount of CH4 produced and has the advantages of low cost, speed and efficiency in obtaining results. The study's objective was to determine if the infrared thermography is adequate for predicting the emission of CH4 in hair sheep and the best time after feeding to carry out the measurement. Twelve Santa Inês lambs (females, non-pregnant, with twelve months old and mean body weight of 39.3 ± 2.1kg) remained for two days in respirometric chambers, in a semi-closed system, to determine the CH4 production. The animals were divided into two treatments, according to the diet provided. During this period, seven thermographic photographs were taken, at times - 1h, -0.5h, 0h, 0.5h, 1h, 2h, 3h, 5h, and 7h, according to the feeding time, defined as 0h. CH4 production was measured over 24h. Thermographic images measured the maximum, minimum, average and point temperatures at the left and right flanks. The temperature difference between the left and right flanks (left minus right) was calculated each time. Pearson correlation coefficients, multiple regression and principal component analysis were carried out in SAS®. The best prediction of emission intensity of CH4 (kg of CH4 per dry matter intake) was obtained at 3h after feeding: CH4/DMI = 13.9016-0,38673 * DifP2 + 3.39089 * DifMed2 (R² = 0.48), using the difference between left and right flanks for point and average temperature measures. Therefore, infrared thermography can be used as an indicator of CH4 production in hair sheep three hours after feeding.

On the glow of cremated remains: long-lived green photo-luminescence of heat-treated human bones.

The long-lived green luminescence of human bone (that has been heated to 600°C for a short duration) is attributed to a carbon quantum dot material (derived from collagen) encapsulated and protected by an inorganic matrix (derived from bone apatite) and is more intense in dense rigid and crystalline parts of (healthy) human bones. The strong collagen-apatite interaction results (upon decomposition) in a protective inorganic environment of the luminescent centers allowing long-lived triplet-based emission of a carbon (quantum) dot-like material at room temperature, as well as resilience against oxidation between 550 and 650°C. The graphitic black phase (obtained upon heating around 400°C) is a precursor to the luminescent carbon-based material, that is strongly interacting with the crystalline inorganic matrix. Human bone samples that have been heated to 600°C were subjected to steady-state and time-resolved spectroscopy. Excitation-emission matrix (EEM) luminescence spectroscopy revealed a broad range of excitation and emission wavelengths, indicating a heterogeneous system with a broad density of emissive states. The effect of low temperature on the heat-treated bone was studied with Cryogenic Steady State Luminescence Spectroscopy. Cooling the bone to 80K leads to a slight increase in total emission intensity as well as an intensity increase towards to red part of the spectrum, incompatible with a defect state model displaying luminescent charge recombination in the inorganic matrix. Time-resolved spectroscopy with an Optical Multichannel Analyzer (OMA) and Time Correlated Single Photon Counting (TCSPC) of these samples showed that the decay could be fitted with a multi-exponential decay model as well as with second-order decay kinetics. Confocal Microscopy revealed distinct (plywood type) structures in the bone and high intensity-fast decay areas as well as a spatially heterogeneous distribution of green and (fewer) red emissive species. The use of the ATTO 565 dye aided in bone-structure visualization by chemical adsorption. Conceptually our data interpretation corresponds to previous reports from the material science field on luminescent powders.

Dehydro acetic acid analogue Schiff base as multimode fluorescence chemosensors for Th4+ and Ni2+ ions and its application to in-vivo bioimaging

Dehydroacetic acid analogue (DHA) and 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide (COM) Schiff base ligand (COM-DHA)as dual-mode fluorescence chemosensorwas synthesized and structurally characterised by using elemental analysis, FTIR, NMR, and Mass analysis. The free probe COM-DHA shows distinct fluorescence emission at 476 nm, upon interaction with Ni2+ the emission intensity was quenched and with Th4+ the emission intensity was redshirted to 500 nm. Further, the ratiometric fluorescence change (I500/I476) was used to detect Th4+, and a turn-off fluorescence probe COM-DHA at 476 nm was used to detect Ni2+ ions. The COM-DHA forms a 2:1 stoichiometric complex with both Ni2+/Th4+ ions with an estimated association constant of 4.84 × 104 and 6.68 × 104 M−2 respectively. A further probe COM-DHA is that it has a wide working pH range (5 to 10) with a short response time (2 to 3 min). The detection limit of COM-DHA towards Ni2+ and Th4+ was found to be 77.8and 48.7 nM, respectively. The, DFT/TD-DFT calculations and FTIR analysis were used to study the binding mechanism between COM-DAH and Ni2+/Th4+ ions. Furthermore, the proposed probe COM-DHAhas successfully quantified trace amounts of Ni2+ and Th4+in real samples and applied them to the in-vivo bioimaging of Th4+ in C. elegans model.

ESIPT+TICT-based Near-IR Detection of Al3+ and F- in Live Cells: Molecular Docking with Acetylcholinesterase.

The interplay of ESIPT+TICT mechanisms in 1,8-naphthalimide-hydroxyquinoline (NQ-OH) molecular rotor were reported for the near-IR 'turn-on' emission (λmax 600 nm) and ratiometric (A405nm/A345nm) absorbance-based detection of Al3+ ions in aqueous medium and live cells which were supported by NMR, IR and CV techniques. The limit of detection (LOD) for Al3+ ions is 100 nM and 14.57 nM. The self-assembled spherical aggregates of NQ-OH transformed into cuboidal aggregates upon coordination with Al3+ ions supported by microscopic and dynamic light scattering (DLS) techniques. The complex NQ-OH+Al3+ was further used for the secondary detection of F- ions in aqueous medium via displacement approach with LOD as low as 2.67 nM. A deeper study revealed that the NQ-OH is a solvatochromic dye. Probably, the NQ-OH either in the aggregated state or in the coordination state with Al3+ ions, showed an increase in the emission intensity at 600 nm due to inhibition of the ESIPT process and trigger of the TICT process. We have demonstrated the utility of NQ-OH for the detection of Al3+ ions and NQ-OH+Al3+ complex for the detection of F- ions in MCF7 live cells. We have also discussed the molecular docking studies of NQ-OH with acetylcholinesterase enzyme.

Soil pH-dependent efficacy of DMPP in mitigating nitrous oxide under different land uses

The emission pathways and intensities of nitrous oxide (N2O) vary across land uses, and the efficacy of mitigation measures may also differ. To investigate the key factors influencing the effectiveness of the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) in mitigating N2O under various land use conditions, we collected ten pairs of soils from tea plantations and adjacent cultivated land for laboratory incubation. As a complementary study, we conducted a meta-analysis based on 261 pairs of observations from 40 incubation studies to investigate the determinants of soil N2O mitigation by DMPP and to validate our experimental results. Results of the incubation experiment showed that DMPP was significantly less effective in mitigating N2O in tea plantation soils (73%) than in cropland soils (82%). Soil pH is a key factor influencing DMPP efficiency under different land use conditions. The lower pH of acidic tea plantation soils resulted in lower abundance and activity of ammonia-oxidizing bacteria (AOB). Under these low pH conditions, heterotrophic nitrification became an important source of N2O emissions in acidic tea plantation soils. As DMPP primarily inhibits AOB, it was less effective against heterotrophic nitrification, which likely contributed to its reduced efficacy in tea plantation soils compared to cropland soils. Our meta-analysis further confirmed the critical role of soil pH in determining DMPP effectiveness. The effect of soil pH on DMPP efficacy was mainly attributed to its regulation of heterotrophic and AOB-derived nitrification. These findings suggest that the field efficacy of DMPP in N2O abatement in tea plantations requires further investigation. Given the significant contribution of heterotrophic nitrification to N2O emissions in strongly acidic tea plantation soils, alternative N2O mitigation strategies should be explored.

Geo-political risks, uncertainty, financial development, renewable energy, and carbon intensity: Empirical evidence from countries at high geo-political risks

Geopolitical risks and uncertainty negatively affect the economy and environmental quality. High geopolitical risks and high uncertainty increase carbon emission intensity by increasing dependence on fossil fuels. However, research in this area is still in its infancy and more empirical evidence is needed to justify the causal link. This research examines the causal mechanism linking geopolitical risk, uncertainty, financial development, renewable energy, and carbon intensity in a sample of eighteen countries with high geopolitical risk between 1985 and 2021. The selected countries have a high intensity of geopolitical risks due to internal and external conflicts that have worsened in recent years. We employ cointegration techniques from Hatemi-J [1] and Maki [2] in the presence of structural breaks, fully modified ordinary least squares (FMOLS), canonical cointegration regression (CCR) models, and static time-variant Granger causality (1969) test. We find robust empirical evidence that geopolitical risk, financial development, renewable energy, uncertainty, and carbon intensity have a cointegrating relationship in the presence of structural breaks. Results from FMOLS and CCR models indicate that carbon intensity responds differently to changes in geopolitical risk, renewable energy, uncertainty, and financial development. Environmental and energy policymakers should mitigate carbon intensity through long-run rather than short-run mechanisms to achieve SDG12 and SDG13.

Increase the inversion degree in Er-doped MgGa2O4 spinel nanofilms to obtain strong electroluminescence

The Ga2O3/MgO/Er2O3 nanolaminates are fabricated by atomic layer deposition and crystallized into Er-doped MgGa2O4 spinel (MGS:Er) nanofilms after annealing, with their electroluminescence (EL) performance characterized. The annealing above 600 °C achieves the polycrystalline spinel nanofilm, and the crystallization is promoted by the higher annealing temperature and Ga2O3/MgO ratio. The dopant Er3+ ions preferably substitute into the octahedron sites occupied by Ga3+ ions in ordinary spinel and Mg2+ in anti-spinel lattice, while the inversion degree is confirmed to increase with the reduction of Ga2O3/MgO ratio and annealing temperature, resulting the relatively enhanced secondary EL at 1542 nm. This perturbation by Er3+-substitution into anti-spinel sites improves the emission intensity and excitation efficiencies, the main EL emission peaking at 1531 nm from the optimal MGS:Er device exhibits the excitation efficiency reaching 5.8%, with the enhanced electrical injection realizing the maximum EL intensity above 17.3 mW/cm2. The fluorescence lifetime of these MGS:Er devices is established in the range of 371-760 μs, which decreases mainly with the Er concentrations. The prototype device using the near-stoichiometric Ga2O3/MgO ratio shows the operation time of 1.12×105 s. This work explores the fabrication of Si-based spinel nanofilms with designed composition and special microstructure, and their practical application in optoelectronics.

Carbon dioxide emission equivalent calculation and inter-sectoral transfer pattern of different water use terminals in China

In the context of global climate change, all industries have put forward the requirements for carbon emission reduction. The effective use of water resources is the key to achieving carbon emission reduction, so it is particularly important to review the carbon dioxide emission equivalents of water resource utilization behaviors (CEE-WRUBs) of water users. However, existing research on CEE-WRUBs across various water sectors remains inadequate. Therefore, this study integrates the enhanced CEEA method, LMDI decomposition model, and IOA method to analyze CEE-WRUBs across diverse water use terminals. Then seeks their main driving factors and their transfer pattern among different industries, which are crucial to the realization of the global carbon neutrality objective. The results showed that: (1) China's CEE-WRUBs show a significant downward trend. Industrial water use emerges as the primary source of CEE, but the CEE-WRUBs of most industrial water terminals show a fluctuating downward trend. Grains' water use behavior (WRUBs) absorbed the largest CEE, reaching 14,698 Mt in 2020. (2) the water efficiency effect emerges as the predominant driver behind the increase in CEE-WRUBs most of the time, and holding a prominent position. The carbon emission intensity effect primarily steers the reduction of CEE-WRUBs. (3) the largest net outflow sector of WRUBs embodied carbon in 2007-2020 was transformed from basic material heavy industry (-153.54 Mt in 2007) to agriculture (-128.26 Mt in 2020). Most of the WRUBs embodied carbon of agriculture flows into light industry, while most of the WRUBs embodied carbon of basic material heavy industry flows into finishing heavy industry and construction. The methods and results of this study provide a potential reference for investigating the regional water-carbon relationship and advancing the global carbon neutrality objective.

Charge reconstruction from simultaneous Fe coordination and P/O co-doping in g-C3N4 for efficient photo-reductive recovery of uranium(VI)

The risk of radionuclide leakage always threats ecological security and human health, making the recovery of uranium from nuclear wastewater a meaningful and urgent issue. However, the low-cost and efficient capture of uranium remains a challenge at present. In this study, a homemade photocatalyst of iron coordinated graphitic carbon nitride (g-C3N4) co-doped with phosphorus and oxygen (OPFCN), which was facilely synthesized through a novel one-step thermal polymerization method, exhibited superior photoelectric efficiency and photocatalytic activity towards the photo-reductive capture of uranium(VI). The simultaneous Fe coordination and P/O co-doping in framework of g-C3N4 played a synergistic effect in charge reconstruction, in which electrons migration driven by coordinated Fe and lone electron pairs delocalization from doped P/O enormously increased electron density and enhanced charge transfer, thus effectively promoting the separation of photogenerated charge carriers. The specific surface area, pore volume and average pore size of OPFCN reached 70.2 m2·g−1, 0.157 cm3·g−1 and 7.78 nm, respectively, exhibiting a trend increasingly beneficial for photocatalytic adsorption and mass transfer with successive introduction of Fe, P and O into original g-C3N4. With the simultaneous introduction of Fe, P and O, the optical absorption edge underwent a significant redshift and fluorescence emission intensity dropped by 75 % compared to that of CN, demonstrating the enhanced visible light capturing ability and significantly inhibited recombination of photogenerated charge carriers in OPFCN. As a result, a uranium capture rate of over 98 % was achieved with catalyst dosage of only 5:1 at pH 5 with OPFCN, demonstrating its competitive photo-reductive activity towards uranium(VI) uptake compared with previously reported g-C3N4-based photocatalysts. Meanwhile, OPFCN exhibited remarkable reusability and stability with even over 65 % uranium recovery rate and almost unchanged peak patterns in XRD and FT-IR in fifth reuse recycle. Additionally, it was demonstrated that e− and O2•− were the direct active species to realize the photoreduction of uranium(VI) over OPFCN, in which e− played the dominant role. The modification method of simultaneous Fe coordination and P/O co-doping would be expected to effectively promote the utilization of g-C3N4-based photocatalysts towards photo-reductive recovery of uranium(VI) from radioactive wastewater.

Concentration- and temperature- dependent luminescence mechanisms and fluorescence dynamic temperature sensing of NaY(MoO4)2:Tb3+ phosphors

High-temperature solid-state reaction technique was used to prepare NaY(MoO4)2:Tb3+ phosphors with different Tb3+ concentrations. XRD patterns showed that the prepared samples contained only single-phased compound NaY(MoO4)2. The concentration-dependent green luminescent intensity of Tb3+ was studied, and it was found that the concentration quenching process is in charge of Ozawa’s model. The concentration-effect of luminescence decay of 5D4 level was explained by the Auzel’s self-generated quenching theory. Starting from the Reisfeld’s theory, the analysis on the luminescence decays also indicated exchange interaction was responsible for the concentration quenching. Temperature dependences of the green emission intensity and decay were comprehended based on the crossover mechanism. A novel temperature sensing technique rooting in the fluorescence dynamics of 5D4 level of Tb3+ in NaY(MoO4)2 was proposed, and the absolute and relative sensitivities were deduced and assessed.

GHG emission quantification and reduction pathway of subway shield tunnel engineering: a case study on Guangzhou Metro, China.

The shield method is a commonly used construction technique in subway tunnel engineering. However, studies on greenhouse gas (GHG) emissions specifically in subway shield tunnel engineering are lacking. This study aims to investigate the GHG emission characteristics and GHG reduction pathways during the construction period of subway shield tunnels. Firstly, based on the life cycle assessment (LCA) method, a greenhouse gas (GHG) emission quantification model for the shield tunnel construction period was developed using a multi-level decomposition of construction. Then, the GHG emission level and intensity during the construction period of a case project are quantified, and its emission characteristics and GHG reduction potential points are assessed. Finally, a comprehensive path for GHG reduction in subway shield tunnel engineering is proposed. The research results indicate that constructing 1 km of subway shield tunnel can generate 19,294.28 t CO2eq. Among these, material production element dominates the emissions with a percentage of 89.05%, while transportation and mechanical construction elements contribute 1.81% and 9.14%, respectively. From the structure perspective, the main structure contributes 88.73% of total emissions, while the ancillary structure contributes 11.27%. Among them, the working shaft and tunnel segments are the main sources of emissions for the main structure, accounting for 23.65% and 65.08%, respectively. Connecting channel and end reinforcement are the main emission sources of the ancillary structures, accounting for 43.63% and 31.30%, respectively. These findings provide a scientific foundation for the environmentally friendly transformation of urban railway development regarding pursuing "carbon peaking and carbon neutrality" strategic goals.

CATHODIC AND ANODIC PLASMA ELECTROLYSIS ON NITRATE SYNTHESIS

Nitrogen fixation using plasma electrolysis is an alternative in the production of liquid nitrate fertilizer which is safe for the environment because it does not produce emissions that pollute the environment. The effectiveness of nitrate production is shown from the position of plasma formation at cathodic and anodic levels. This study aims to analyze the comparison of cathodic and anodic plasma electrolysis levels in producing nitrate. Current-voltage characterization is carried out to determine the position of plasma formation. The glow discharge of the cathodic plasma is achieved after the critical voltage (280 V) is lower than that of the anodic plasma (650 V). Measurement of emission intensity using electron spin resonance to determine reactive species that play a role in the formation of nitrate in cathodic and anodic plasma. Nitrate formation is influenced by reactive species in the form of N, N2*, N2+, •OH, •H and •O, especially reactive species of nitrogen and •OH are needed to form nitrate both from the NO pathway (anodic plasma) and from the ammonia pathway (cathodic plasma). The results of this study showed that anodic plasma electrolysis was more effective for nitrate synthesis. Nitrate produced from anodic plasma is 1889 mg L-1, greater than cathodic plasma as much as 213 mg L-1.

Low-emission hydrogen production from gasification of Australian coals – Process simulation and technoeconomic assessment

Although renewable energy-based technologies such as water electrolysis and biomass gasification for hydrogen production are cleaner than fossil energy-based routes, there are still prevailing challenges associated with the high cost and operational challenges in the scale-up of those technologies in the short term. Considering the abundance of coal as a current primary source of energy in Australia, the use of coal to produce hydrogen is not only in line with Australia's resource endowment but is also expected to become a supplement to the other hydrogen production pathways during the global energy transition period. This paper presents a comprehensive techno-economic assessment of low-emission hydrogen production from Australian coal gasification integrated with carbon capture and storage (CCS). The study explores four cases of hydrogen production, comparing Australian brown coal (Victorian brown coal) and black coal (Queensland black coal) gasification. Variations in gasifiers, gasification agents, and associated operating conditions contribute to differences in energy efficiency, costs, and CO2 emissions among the cases. The findings reveal a levelized cost of hydrogen from coal gasification ranging between A$4.12–4.90 per kg of hydrogen. Notably, entrained flow gasification of Victorian brown coal in a mixture of oxygen and steam environment demonstrates advantages under the current market conditions. However, less mature technologies like dual fluidized bed gasifiers could emerge as viable alternatives if deployed on a commercial scale. The study also addresses direct carbon emissions from the process, indicating a CO2 emission intensity range of 16.3–20.9 kg CO2/kg H2 without CCS and 0.1–1.1 kg CO2/kg H2 with CCS for the four cases. These insights contribute valuable information for decision-making in the pursuit of sustainable and economically feasible hydrogen production methods during the ongoing energy transition.

Impact of composition of AlGaInAs confining barriers on emission of InAs quantum dots embedded in AlGaAs/GaAs dot-in-a-well heterostructures

The emission of InAs quantum dots (QDs) grown on Al0.30 Ga0.70As/GaAs heterostructures and integrated into additional capping/buffer quantum wells (QW), known as dot-in-a-well (DWELL) structures, has been investigated. Two different AlGaInAs confining barriers (CBs) and buffer layers (BLs) are compared. The first QD structure includes the Al0.30 Ga0.70As CB (#1) and the In0.15Ga0.85As BL. The second QD structure consists of the Al0.40Ga0.45In0.15As CB (#2) and the In0.25Ga0.75As BL. Comparison of photoluminescence (PL) spectra has revealed that the ground state (GS) emission band in the structure #2 with Al0.40Ga0.45In0.15As CB is characterized by the lower peak energy, smaller PL linewidth (more homogeneous QD sizes) and higher GS emission intensity compared to that parameters in the structure #1 with Al0.30 Ga0.70As CB. The smaller potential barriers at the Al0.40Ga0.45In0.15As CB/QD interfaces in #2 lead to faster thermal decrease in the GS PL intensity at high temperatures compared with that in #1. High-resolution X-ray diffraction (HR-XRD) method was used for the study of the QD structures with the aim of monitoring the sizes and compositions of QDs and QWs. Numerical simulation of HR-XRD scans has shown that the material compositions of QDs and QW in #2 with Al0.40Ga0.45In0.15As CB has not changed in the process of QD structure growth at high temperatures compared to those in #1. The obtained results are interesting for further improvement of InAs/GaAs QD structures for telecommunication technology and optoelectronic applications.

The Economic Policy Uncertainty on Firms Behavior

The study examines how economic policy uncertainty could affect firm behavior. It discusses how changes in economic policies can affect investment decisions, capital expenditure, innovation, and green behavior of firms. This topic focuses on analyzing the relationship between corporate financial decisions and consumer spending under policy uncertainty. It also explores the relationship between policy uncertainty and firms' overseas investments, environmental performance, governance practices, tax avoidance strategies, and cash-effective tax rates. The findings reveal the importance of cash holdings in alleviating the effects of policy uncertainty on firm activities and highlight the relationship between policy uncertainty and firms' carbon emission intensity. Overall, the study provides insights into the various aspects of corporate decision-making affected by economic policy uncertainty.

Impact of agricultural product brands and agricultural industry agglomeration on agricultural carbon emissions

Agricultural carbon emissions pose a significant challenge in combating climate change and achieving sustainable development objectives. These emissions predominantly stem from the decisions made by stakeholders, and the potential economic and social benefits associated with agricultural product brands determine their capacity to influence stakeholder behavior. This study utilizes panel data from 30 provinces in China spanning from 2008 to 2021 to examine the impact of agricultural product brands on agricultural carbon emission intensity and its underlying mechanisms. The findings indicate that: (1) Agricultural product brands contribute to lowering agricultural carbon emission intensity within a region, while also exerting a negative spillover effect on neighboring areas. (2) Agricultural product brands foster a decline in agricultural carbon emission intensity by bolstering the agricultural industry agglomeration. (3) Agricultural scale operation exhibits a threshold effect between agricultural product brands and agricultural carbon emission intensity, with the mitigation effect becoming increasingly pronounced as the threshold range expands. The research findings can offer valuable insights into leveraging the advantages of agricultural product brands to facilitate the reduction of agricultural carbon emissions.

Spatio-temporal distribution and peak prediction of energy consumption and carbon emissions of residential buildings in China

With the acceleration of urbanization and the improvement of people's living standards, the carbon emissions of residential buildings (BCE) in China have been increasing, hindering the achievement of carbon peaking and carbon neutrality goals. It has become increasingly urgent and important to analyze and grasp the dynamic trends of BCE. Given the notable regional variations in carbon emissions, it is necessary to delve into the distribution characteristics of BCE and the underlying factors influencing them. First, based on the emission factor method, the energy consumption and carbon emissions calculation models are established. Next, the main influencing factors are obtained by improving Kaya's constant equation. Meanwhile, the GA-PPC-Kmeans model is established to divide BCE into different regions. Then, the STIRPAT-Ridge model is built to predict the peak carbon emissions. Finally, a combination of static and dynamic methods is used to forecast peaks under three scenarios, which are low-carbon (LC) scenario, baseline (BA) scenario, and high-carbon (HC) scenario. The results show that five pivotal factors significantly impact BCE in China, which are energy carbon emission intensity (ECEI), energy intensity (EI), economic density (ED), residential housing level (RHL) and population size(P). Furthermore, BCE is categorized into five distinct regions: low-carbon demonstration area, energy efficiency improvement area, carbon concentration and innovation area, high-carbon optimization area, and carbon poverty development area. Under BA scenario, the peaks for BCE in these regions converge primarily around 2040 and 2045. This study provides a regional research perspective for China's residential buildings to reach the peak of carbon emissions, and serves as a reference for formulating carbon emission reduction plans in different regions.

Manifestation of the normal intensity distribution law (NIDL) in the rovibrational emission spectrum of hydroxyl radical

The latest experimental [Noll et al. Atmos. Chem. Phys. 20, 5269 (2020)] and theoretical [Brooke et al. J. Quant. Spectr. Rad. Transfer 168, 142 (2016)] data on the OH emission intensities are analysed with use of the NIDL. It is found that the calculated intensities of the Δ v > 6 transitions should not be trusted. The analysis of the OH data revealed that the NIDL theory is not applicable to the satellite bands. The effect of small reduced mass previously discovered in H 2 [Ushakov et al. J. Mol. Spectrosc. 399, 111863 (2024)], causing the NIDL straight-line slope to be larger than the one associated with the repulsive branch of the potential, is demonstrated in OH, and the same should be true of all the diatomic hydrides. We performed ab initio calculations of the OH repulsive branch and compared it with the one of Brooke et al. and the other due to Varandas and Voronin [Chem. Phys. 194, 91 (1995)]. We found that the ab initio PEF closely follows the Varandas-Voronin potential in the repulsive region important for calculating the overtone intensities [Medvedev, J. Chem. Phys. 137, 174307 (2012)].

Bioinspired Polyoxomolybdate Nanoclusters Peroxidase‐Mimicking Nanozyme for Dual‐Mode Detection of Methotrexate in Real Samples

ABSTRACTMethotrexate (MTX) is a chemotherapy agent and immune system suppressant that is widely used to treat a variety of malignant and nonmalignant diseases. Due to some drawbacks of the existing methods for the determination of MTX in aquatic and real samples, we prepared a new, simple, and selective dual‐mode fluorometric and electrochemical approach based on peroxidase‐mimic [Mo36] polyoxomolybdate nanoclusters (POMo) for sensing MTX. A turn‐on–off fluorometric approach for the detection of MTX was developed, which was based on the inhibition of the emission intensity of the terephthalic acid (TA)‐H2O2 system upon the addition of MTX to the reaction solution. The electrocatalytic performance of the obtained POMo was studied after making a carbon paste electrode (CPE) utilizing cyclic voltammetry and amperometry analysis. Under the optimum condition, good linearity was observed between the quenched emission intensity of the system and MTX dosage in the range of 0.5–250 μM with a limit of detection (LOD) of 0.91 μM. The electrochemical method illustrated a much better response with an extensive linear range of 0.01–475 μM and a lower LOD (1.61 nM). Analytical recoveries and RSD% values were, respectively, in the range of 87.72%–110% and 0.33%–1.32% for the fluorometric system and 96%–106% and 0.77%–1.02% for the electrochemical platform. Finally, the selectivity of the sensor was evaluated against various common interfering species, and the results indicated satisfactory selectivity of the POMo dual‐mode system towards MTX.