High Nitrogen Content Research Articles

Mesoporous Nitrogen-Doped Carbon Support from ZIF-8 for Pt Catalysts in Oxygen Reduction Reaction

Zeolitic imidazolate framework-8 (ZIF-8) has been extensively studied as a precursor for nitrogen-doped carbon (NC) materials due to its high surface area, tunable porosity, and adjustable nitrogen content. However, the intrinsic microporous structure of the ZIF-8 limits mass transport and accessibility of reactants to active sites, reducing its effectiveness in electrochemical applications. In this study, a soft templating approach using a triblock copolymer was used to prepare mesoporous ZIF-8-derived NC (Meso-ZIF-NC) samples. The hierarchical porous structure was investigated by varying the ratios of Pluronic F-127, NaClO4, and toluene. The resulting Meso-ZIF-NC exhibited widespread pore size distribution with an enhanced mesopore (2–50 nm) volume according to the composition of the reaction mixtures. Pt nanoparticles were uniformly dispersed on the Meso-ZIF-NC to form Pt/Meso-ZIF-NC catalysts, which presented a high electrochemical surface area and improved oxygen reduction reaction activity. The study highlights the important role of mesopore structure and nitrogen doping in enhancing catalytic performance, providing a pathway for advanced fuel cell catalyst design.

A Promising Strategy for Searching High Energy Density Materials Based on 2,4,5‐Trinitro‐Imidazole Functional Backbone

AbstractA series of high energy density compounds are designed by altering the triazole, tetrazine, oxadiazole rings and energetic groups (such as −CN, −N3, −NH2, −NHNH2, −NO2, −NHNO2, −C(NO2)3, −CH(NO2)2) into 2,4,5‐trinitro‐imidazole skeleton. Their structures are optimized by density functional theory (DFT) methods at B3LYP/6‐311G (d,p) method. Based on the optimized structures, the impact of different rings and energetic groups on their energy gaps, heats of formation, detonation performance and sensitivities are investigated. The results show that compound F4 possesses the highest values of heats of formation due to their high nitrogen content. However, compound F2 possesses the highest values of detonation pressure and detonation velocity which indicates that the detonation performance are determined by values of density rather than those of heats of formation. Taking both detonation performance and impact sensitivities into consideration, compounds B4, C4, F4, I4, J4 and J8 are screened as high energy density compounds due to their excellent detonation performance and acceptable sensitivities compared to those of RDX. Finally, the distribution of frontier molecular orbital, the electrostatic potential area distribution, thermodynamic properties and weak interactions of the screened compounds are fully investigated.

Photon budgets and the relative effects of CDOM and pigment absorptions on primary production along a coastal salinity gradient

The study highlights the critical role of CDOM in coastal light attenuation and its impact on primary production (PP). We investigated the spectral attenuation of light due to water, phytoplankton pigments, detritus and coloured dissolved organic matter (CDOM) along a salinity gradient in the outer Oslofjord, Norway. By examining the effects of these components across different seasons, we aimed to elucidate their relative contributions to light absorption and PP. The findings suggest that increased terrestrial CDOM inputs, driven by climate, changed atmospheric deposition and land-use changes, could significantly affect coastal ecosystems by altering light attenuation and consequently PP and potentially leading to other ecological pressures. CDOM consistently dominated light absorption across all stations and seasons, contributing 50%–80% of the total absorption of photosynthetically active radiation. The absorption by CDOM and detritus decreased with increasing salinity, while phytoplankton absorption followed a seasonal succession. PP estimates show high seasonal variability from maximums in June to minimums in November, mainly attributed to, changes in seasonal light availability and phytoplankton biomass, followed by light attenuation by CDOM and differences in quantum yields of photosystem II (PSII). Nutrient analysis showed a seasonal pattern, with the highest nitrogen concentrations in November and depletion during more productive seasons, as well as conservative mixing throughout the salinity gradient. CDOM absorption played substantial, albeit not leading, role in influencing PP estimates, derived from a bio-optical model. CDOM was the main determinant of light attenuation across most wavelegnths.

Molecular Design and Theoretical Study on Dioxadiazine Energetic Compounds Involving Intramolecular Hydrogen Bonds

ABSTRACTThe high nitrogen and high oxygen content of energetic dioxadiazine compounds makes them exhibit high detonation performance and good stability, showing possible application in both military and civilian fields. Energetic dioxadiazine compounds with intramolecular hydrogen bonds were designed and optimized, while introducing —NH2, —NHNO2, —CH3, —NO2, and —OH as modified groups. The bond order, density, enthalpy of formation, stability, detonation performance and inter/intramolecular interactions were analyzed. Results showed that the skeleton of 1,4,2,6‐dioxadiazine and 1,4,2,5‐dioxadiazine had good stability and symmetrical structure. Analysis of bond length revealed the strong hydrogen bonding between the hydroxyl group and dioxadiazine ring. The introduction of —NH2 and —OH groups proved beneficial in increasing molecular planarity. Bond order analysis, molecular electrostatic potential (ESP) analysis and detonation parameter calculations showed that B5 and C5 have good stability and detonation properties. Crystal structure prediction suggested that B5 would most likely crystallize in monoclinic (P21 space group) while C5 would crystallize in orthorhombic (Pbca space group). Hirshfeld surface analysis indicated strong O···H and N···H interactions for compounds B5 and C5. The above results have a positive promoting effect on obtaining high‐energy dioxadiazine compounds with high stability.

Protein-Guided Biomimetic Calcification Constructing 3D Nitrogen-Rich Core-Shell Structures Realizing High-Performance Lithium-Sulfur Batteries.

Biomimetic calcification is a micro-crystallization process that mimics the natural biomineralization process, where biomacromolecules regulate the formation of inorganic minerals. In this study, it is presented that a protein-assisted biomimetic calcification method for the in situ synthesis of nitrogen-doped metal-organic framework (MOF) materials. A series of unique core-shell structures are created by utilizing proteins as templates and guiding agents in the nucleation step, creating ideal conditions for shell growth. To further understand the influence of the protein and organic ligand on the morphology of the MOF shell, the competing mechanism toward metal ions is supposed. Through systematic experiments and analyses, a strategy to construct unique precursor structures by controlling calcification nucleation is proposed. After carbonization, protein-containing precursors exhibit exceptional porous characteristics, stability, and high nitrogen content. These attributes make them promising materials as sulfur hosts in lithium-sulfur batteries (LSB). Electrochemical tests confirm that biomimetic calcification-assisted 3D carbonaceous structure can effectively immobilize dissolved polysulfides, demonstrating strong adsorption and catalytic capabilities. This discovery not only opens up new avenues for employing biomimetic calcification as a sustainable method for batteries but also enlightens the fields of materials science, catalytic chemistry, and energy storage.

Evaluation of the aerobic process performance for treating tannery effluent in the fungicide presence and ammoniacal nitrogen high concentration

Leather processing is characterized by the generation of effluents with a high concentration of ammonia nitrogen (N-NH4+) and the presence of fungicides. This study evaluated the interference of these two constituents on the removal of chemical oxygen demand (COD) and N-NH4+. To this end, an aerated reactor operating in a batch system was used. The effects of cycle time, fungicide volume, and initial N-NH4+ concentration on COD and N-NH4+ removal was evaluated using a Centralized Rotational Composite Design. The highest COD removal (45.45%) occurred under the conditions of 72 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (8.24%) occurred under the conditions of 24 h, 0.28 mL of fungicide and 84.8 mg L-1 of N-NH4+. The highest removal of N-NH4+ (38.49%) occurred under the conditions of 42 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (4.26%) occurred under the conditions of 24.1 h, 0.82 mL of fungicide and 84.8 mg L-1 of N-NH4+. Through statistical analysis, it was possible to obtain mathematical models for the two response variables, which satisfactorily described the removal efficiency of COD and N-NH4+, and through the desirability analysis, it was possible to optimize the treatment process operation with a cycle time of 58.15h, with the addition of 0.62 mL of fungicide and 57.91 mg L-1 of ammoniacal nitrogen. Although the removal of N-NH4+ via nitrification is an efficient technique in industrial effluent treatment, the results obtained in this work indicate that the removal of N-NH4+ was significantly affected by the presence of the fungicide. Keywords: biological treatment, chemical oxygen demand, DCCR, TCMTB.

Transition Metal-Mediated Preparation of Nitrogen-Doped Porous Carbon for Advanced Zinc-Ion Hybrid Capacitors

Carbon is predominantly used in zinc-ion hybrid capacitors (ZIHCs) as an electrode material. Nitrogen doping and strategic design can enhance its electrochemical properties. Melamine formaldehyde resin, serving as a hard carbon precursor, synthesizes nitrogen-doped porous carbon after annealing. Incorporating transition metal catalysts like Ni, Co, and Fe alters the morphology, pore structure, graphitization degree, and nitrogen doping types/proportions. Electrochemical tests reveal a superior capacitance of 159.5 F g−1 at a scan rate of 1 mV s−1 and rate performance in Fe-catalyzed N-doped porous carbon (Fe-NDPC). Advanced analysis shows Fe-NDPC’s high graphitic nitrogen content and graphitization degree, boosting its electric double-layer capacitance (EDLC) and pseudocapacitance. Its abundant micro- and mesopores increase the surface area fourfold compared to non-catalyzed samples, favoring EDLC and fast electrolyte transport. This study guides catalyst application in carbon materials for supercapacitors, illuminating how catalysts influence nitrogen-doped porous carbon structure and performance.

Application of novel silica stabilized on a covalent triazine framework as a highly efficient heterogeneous and recyclable catalyst in the effective green synthesis of porphyrins.

In this study, we present the design, synthesis, and utilization of a covalent triazine framework (CTF) formed by the condensation of N 2,N 4,N 6-tris(4-(aminomethyl)benzyl)-1,3,5-triazine-2,4,6-triamine and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine on which silica is immobilized (TPT-TAT/silica) as an innovative catalyst for porphyrins synthesis. Under solvothermal conditions, the condensation of triamine and trialdehyde precursors led to the formation of a covalent triazine framework (CTF) with a high nitrogen content. The resulting CTF is characterized by its extensive porosity and elevated nitrogen levels, which are critical for the creation of catalytic active sites. This framework demonstrated exceptional catalytic performance in the synthesis of porphyrins. Substituting aerobic conditions in lieu of costly oxidizing agents represents a significant advancement in our methodology. Due to the insolubility of the catalyst, it is possible to separate it from the reaction mixture through filtration or centrifugation. This property enhances its reusability and minimizes waste generation. This development in the synthesis and application of CTFs could pave the way for more sustainable and cost-effective catalytic processes in organic synthesis, particularly in the synthesis of complex molecules like porphyrins. The research highlights the potential of CTFs as versatile materials in catalysis, owing to their structural properties and the ability to tailor their functionalities for specific applications.

Influence of Current Density and Chloride Concentration on the Electrooxidation of Ammonia and Organic Matter in Ammonia-Laden Effluents

Electrooxidation is an efficient method for treating effluents with high concentrations of ammoniacal nitrogen and organic matter (R), in the presence of chloride ions (Cl-).The present study aimed at degrading ammoniacal nitrogen and organic matter from an effluent generated at a fertilizer storage port terminal. For this purpose, a batch electrochemical reactor with mechanical agitation was used, with a Ti/RuO2 anode. The parameters studied were the current density that varied in 20, 40 and 60 mA cm-2, the concentration of chloride ions that was 0.04, 0.74, 0.90 to 0.81 mol L-1 and the electrolysis time that varied from 4.0, 5.0, 7.0 and 8.0 h. A 2² experimental design was conducted to determine the significance level of the parameters studied. The results obtained indicated the removal of 99.99% of N-NH3 and 75.60% of total organic carbon (TOC) when a current density of 60 mA cm-2 and a Cl- concentration of 35.5 g L-1 were applied, after 4.0 h of electrolysis.

Improved Anaerobic Digestion of Food Waste under Ammonia stress by Side-Stream Hydrogen Domestication

High ammonia concentration inhibits archaea's activity, causing the accumulation of H2 and acetate, which suppresses methane production in anaerobic digestion (AD). The study aimed to enhance microbial hydrogen metabolism through a side-stream hydrogen domestication (SHD) strategy, which involves applying hydrogen stimulation to a portion of the sludge separately. SHD maintained a stable methane yield of 407.5 mL/g VS at a high total ammonia nitrogen (TAN) concentration of 3.1 g/L. In contrast, the control group gradually decreased and stopped methane production at a TAN concentration of 2.3 g/L. Further analysis using enzyme activity assays, flow cytometry, and metagenomics explored the mechanisms underlying ammonia tolerance of SHD-treated group. SHD reshaped the microbial community, enriching homoacetogens and Methanosaeta-dominated methanogenic archaea. Key metabolic pathways including homoacetogenesis, butyrate degradation, propionate degradation, and methane production were enhanced. The activity of related enzymes also increased. Gene abundance in energy-generating pathways, such as glycolysis, was enhanced, ensuring adequate ATP production. Additionally, the high gene abundance of ion transport systems contributed to regulating proton imbalance and supplementing intracellular K+. This study provides important insights and practical guidance for developing novel techniques in the field of anaerobic digestion.

Examining the Impact of Microbial Compost from Anaerobic Digestion on Soil Fertility and Maize Crop Nutrient Uptake

This research study was to evaluate the effects of combining microbial compost and mineral fertilizer on soil properties, maize growth, and nutrient uptake. Therefore, after selecting normal soil, 10 kg of soil was placed in each pot. Nine treatments with three replications were applied by using a Completely Randomized Design (CRD) for the study layout. The results revealed that the maximum plant height (101.73 cm), shoot fresh weight (69.36 g), shoot dry weight (128.6 g), root fresh weight (1.68 g), and root dry weight (0.89 g), as well as the highest content of nitrogen (1.66%), the highest phosphorus concentration (1.04%), and the maximum potassium concentration (2.13%) were noted in SF+MM + ½ NPK, while contents of iron (80.2 mg/kg), zinc (98.46 mg/kg), copper (78.66 mg/kg), and manganese (67.7 mg/kg) were also recorded in SF+MM + ½ NPK compared to other treatments. After harvesting maize crops, the lowest pH (7.27), highest EC (0.38 dS/M), and the highest contents of organic matter (1.03%) were recorded in SF+MM + ½ NPK. Maximum nitrogen content in soil (37 mg/kg), phosphorus content in soil (19.7 mg/kg), and potassium content in soil (105.8 mg/kg) were recorded in T8, while maximum contents of iron (4.88 mg/kg), zinc (1.80 mg/kg), copper (0.51 mg/kg), and manganese (1.95 mg/kg) were recorded in SF+MM + ½ NPK. The combination of SF+MM + ½ NPK showed to be the most effective treatment, whereas the usage of compost and chemical fertilizer alone remained the least effective.

Preparation of aminated hardwood kraft lignin by Mannich reaction and its structural and thermal characterization

This study investigated the characteristics of aminated kraft lignin (AKL) prepared from the Mannich reaction of hardwood kraft lignin (KL) and diethylenetriamine (DETA) for future application in dye removal. Three aminated samples—AKL-3.5, AKL-7.5, and AKL-15—were prepared using different amounts of DETA (3.5, 7.5, and 15 mmol). The morphology, chemical, and thermal properties of AKLs were investigated through various instrumental analyses and compared with KL. Elemental analysis showed that AKL-15 contained the highest nitrogen content (8%). Based on scanning electron microscopy (SEM), AKLs exhibited a smoother surface compared to KL and aggregated into clusters. Infrared, X-ray photoelectron and 2D heteronuclear single quantum coherence nuclear magnetic resonance spectroscopy confirmed the successful introduction of primary and secondary amines, and C = N functionality into the lignin structure.31P NMR indicated a decrease in hydroxyl group contents of guaiacyl and p-hydroxyphenyl units and an increase in C5 amine-substituted units for AKL-15. Thermal analyses (TGA and DSC) indicated that AKLs were thermally less stable and reduced glass transition temperature (Tg) than KL. These findings contribute to the limited literature on the amination of hardwood lignin, as most amination studies focus on softwood and grass lignins.

Coffee Pulp and Husk Residue Compost Improve the Growth of Robusta Coffee (Coffea canephora) Seedlings in the Nursery

Background: Compost made from coffee husk and pulp residues could serve as a sustainable alternative to chemical fertilizers for fertilizing coffee fields. Methods: This study was conducted to determine the agronomic value of seven compost formulations based on coffee residues [Husk residues+chicken manure (3:1); Husk residues+chicken manure (2:1); Husk residues+chicken manure (1:1); Husk residues+pig slurry (3:1); husk residues+pig slurry (2:1); pulp residues+chicken manure (3:1); and husk residues+pig slurry (1:1)] mixed in equal proportion with potting soil on the vegetative growth of coffee seedlings in the nursery. The experimental design employed was a completely randomized design with one factor. Result: Six months after planting, the compost based on husk residues+chicken manure (3:1) and the compost based on husk residues+pig slurry (3:1) were found to be more effective. The former led to rapid growth in plant height (46.85 cm compared to 27.1 cm) and diameter. It is followed in terms of effectiveness on height growth by the compost based on husk residues+Pig slurry in proportion (3:1). These composts also had a positive impact on the fresh and dry biomass (aboveground and root) of coffee plants. This can be explained by the high content of organic matter, nitrogen, potassium, calcium and phosphorus in these composts. These two composts mixed in equal proportion with potting soil are recommended for coffee plant production in the nursery. Furthermore, field experimentation would confirm their effectiveness.

Synthesis of a Bimetallic-Doped Phytate-Melamine Composite as an Efficient Additive for Epoxy Resins with High Fire Safety.

The issue of hazardous smoke and toxic gases released from epoxy resins (EP), which often causes casualties in real fires, has limited its application. Therefore, we have developed a novel flame retardant based on a bimetallic-doped phytate-melamine (BPM) structure with Zn2+ and Fe2+ ions incorporated into the polymer matrix using a straightforward solution-based synthetic method. The combustion performance of the composite was evaluated using a cone calorimeter test, which showed that the peak heat release, total heat release, and total smoke production were reduced by 50%, 31.7%, and 29.2%, respectively, compared to those of EP. Additionally, the fire growth index was noticeably reduced by 60% owing to the synergistic catalytic effect of the bimetallic ions, and the high nitrogen and phosphorus content of the additives. Overall, this study provides new insights into the application of bimetallic doping for flame retardant polymer composites.

Novel Approach for Enhancing Challenging Terrains Using an Integrated Pyrolysis and Furrow-Diking Technology

Poultry-processing industries generate substantial quantities of waste, posing significant environmental challenges due to the complexity of handling and disposal. This study explores an innovative solution that combines thermochemical treatment of poultry waste with furrow-diking technology to transform non-recyclable feathers and bones into biochar—a nutrient-rich soil amendment. The research identifies optimal pyrolysis conditions for biochar production and evaluates its effects on soil moisture retention, compaction reduction, and erosion control. Experimental trials on sloped terrains reveal that incorporating biochar into compartmentalized furrows enhances water-holding capacity and soil structure, providing a sustainable approach to addressing agricultural challenges. Pyrolyzing poultry waste at 500 °C produced biochar with high nitrogen content and stability, capable of retaining up to 90% of its mass in water and significantly reducing soil compaction. Furthermore, applying 10 metric tons of biochar per hectare can sequester 5–8 metric tons of carbon annually, contributing to long-term carbon mitigation and regenerative agriculture. This integrated methodology combines waste valorization with ecological restoration, unlocking new opportunities for scalable and sustainable soil-management solutions.

Recovery effects of the long-term cryopreserved Anammox sludge by adjusting the sludge amount

ABSTRACT Anammox process was one of the most promising nitrogen removal technologies. This study investigated the recovery performance of Anammox sludge after 83 days of cryopreservation in two reactors (R1 and R2). Reactor R1 utilized Anammox sludge pretreated with low-substrate simulated wastewater prior to long-term cryopreservation, and successful recovery was achieved by discharging sludge under ammonia nitrogen concentrations of 100 mg/L. The total nitrogen removal efficiency (TNRE) reached 70.0% on day 48. Reactor R2 used Anammox sludge pretreated with high-substrate simulated wastewater before cryopreservation. At an ammonia nitrogen concentration of 100 mg/L, the TNRE reached 87.0% on day 18. After increasing the ammonia nitrogen concentration to 300 mg/L and discharging sludge, the TNRE reached 84.6% on day 38. When the ammonia nitrogen concentration was elevated to 500 mg/L, system performance deteriorated. Recovery was unsatisfactory when the ammonia nitrogen concentration was reduced back to 300 mg/L. Finally, adding Anammox sludge restored the TNRE to 85.6% after 35 days of operation. The results suggest that adding Anammox sludge is essential for nitrogen removal recovery in reactors under high ammonia nitrogen concentration inhibition, while sludge discharge is crucial when free ammonia (FA) is present. This study provides a simple and effective strategy for recovering the activity of Anammox sludge after long-term cryopreservation.

Non-Destructive Detection and Visualization of Chlorophyll Content in Cherry Tomatoes Based on Hyperspectral Technology and Machine Learning

The cherry tomato has an important economic value and an increasingly broad market, and the chlorophyll content of cherry tomato leaves can directly reflect the plant’s photosynthetic ability, thus indirectly reflecting its growth status. Therefore, this paper proposes a regression detection method for chlorophyll in cherry tomato leaves by combining machine learning and hyperspectral technology to realize non-destructive, fast, and more accurate detection. Firstly, Moving-Average (MA) preprocessing was chosen as the pretreatment method for this paper, and three regression models of principal component regression (PCR), random forest (RF), and partial least squares regression (PLSR) were established with leaf chlorophyll under different nitrogen concentrations. The CARS_PLSR algorithm has the highest prediction accuracy with accuracy, precision, RMSEC, and RMSEP of 0.8790, 0.9187, 2.9581, and 2.5578, respectively. The study examined the impact of various nitrogen concentrations on the chlorophyll content of cherry tomato leaves, and it was found that the high concentration of nitrogen inhibited the SPAD value of cherry tomato leaves more than that of the low concentration, and the optimal concentration of nitrogen fertilization for tomatoes was 300 mg·L−1. Finally, a regression model was established by using CARS-PLSR combined with the pseudo-color map technology, and a distribution map of chlorophyll content in different SPAD value gradients of cherry tomato leaves was obtained, which could visualize the distribution of chlorophyll and its distribution sites in the leaves and understand the growth status of cherry tomatoes. The distribution of chlorophyll content in different SPAD values of cherry tomato leaves was obtained by using the CARS-PLSR regression model combined with pseudo-color map technology, which can visualize the distribution of chlorophyll in the leaves and the parts of distribution and understand the growth condition of cherry tomatoes. Finally, the optimal model is applied in conjunction with a sprayer to automate fertilizer application.

Growth, Quality, and Nitrogen Metabolism of Medicago sativa Under Continuous Light from Red-Blue-Green LEDs Responded Better to High Nitrogen Concentrations than Under Red-Blue LEDs.

Alfalfa is a widely grown forage with a high crude protein content. Clarifying the interactions between light quality and nitrogen level on yield and nitrogen metabolism can purposely improve alfalfa productivity in plant factories with artificial light (PFAL). In this study, the growth, quality, and nitrogen metabolism of alfalfa grown in PFAL were investigated using three nitrate-nitrogen concentrations (10, 15, and 20 mM, labeled as N10, N15, and N20) and continuous light (CL) with two light qualities (red-blue and red-blue-green light, labeled as RB-C and RBG-C). The results showed that the adaptation performance of alfalfa to nitrogen concentrations differed under red-blue and red-blue-green CL. Plant height, stem diameter, leaf area, yield, Chl a + b, Chl a, Chl b, crude protein contents, and NiR activity under the RB-CN15 treatment were significantly higher than RB-CN10 and RB-CN20 treatments. The RB-CN20 treatment showed morphological damage, such as plant dwarfing and leaf chlorosis, and physiological damage, including the accumulation of proline, H2O2, and MDA. However, the difference was that under red-blue-green CL, the leaf area, yield, and Chl a + b, carotenoid, nitrate, and glutamate contents under RBG-CN20 treatment were significantly higher than in the RBG-CN10 and RBG-CN15 treatments. Meanwhile, the contents of soluble sugar, starch, and cysteine were significantly lower. However, the crude protein content reached 21.15 mg·g-1. The fresh yield, dry yield, stomatal conductance, leaf area, plant height, stem diameter, crude protein, GS, and free amino acids of alfalfa were positively correlated with increased green light. In addition, with the increase in nitrogen concentration, photosynthetic capacity, NiR, and GOGAT activities increased, promoting growth and improving feeding value. The growth, yield, photosynthetic pigments, carbon, nitrogen substances, and enzyme activities of alfalfa were significantly affected by the interaction between nitrogen concentration and light quality, whereas leaf/stem ratio and DPPH had no effect. In conclusion, RB-CN15 and RBG-CN20 are suitable for the production of alfalfa in PFAL, and green light can increase the threshold for the nitrogen concentration adaptation of alfalfa.

A Study on NbN Thin Films as Resistive Films Prepared via Reactive Magnetron Sputtering

The NbN thin films were deposited onto glass and Al2O3 substrates using reactive magnetron sputtering, employing a niobium target sputtered with a mixture of Ar and N2 gases. The investigation focused on the phase structures, microstructures, and electrical properties of the NbN thin films under various deposition powers and annealing temperatures. The results indicated the presence of a face-centered cubic (FCC) crystal structure in the as-deposited films at a power of 125 W. Interestingly, the crystallization phase remained unchanged within an annealing temperature range from room temperature to 500 °C. It was observed that the resistivity of the NbN thin films increased with higher nitrogen content, while the temperature coefficient of resistance (TCR) showed a tendency towards more negative values as the nitrogen content rose. Notably, at a nitrogen content of 9%, the film exhibited the lowest resistivity of 273 μΩ-cm with a TCR of -240 ppm/°C.

Highly Thermally Stable and Gas Selective Hexaphenylbenzene Tröger's Base Microporous Polymers.

This study shows the multistep synthesis of a series of Tröger's base polymers of intrinsic microporosity (TB-PIMs) based on a hexaphenylbenzene (HPB) core, with a focus on evaluating their thermal stability, porosity, and CO2 capture performance. Both ladder and linear structures were prepared, designed to feature tunable nitrogen content and porosity. Our findings demonstrate that polymers with higher nitrogen content, such as tetra-TB-HPB, exhibit superior CO2 affinity and selectivity, attributed to enhanced interactions with CO2 and optimized micropore sizes. Linear TB-polymers 1 and 2 are also made for comparison and show competitive performance in carbon capture, suggesting that cost-effective, simpler-to-synthesize materials can achieve efficient gas separation. The study reveals that increased porosity significantly enhances CO2 capacity and selectivity, particularly in networked TB-HPB-PIMs with high surface areas and narrow micropores, achieving values up to 544 m2 g-1, CO2 uptake of 2.00 mmol g-1, and CO2/N2 selectivity of 45.6. The thermal properties of these materials, assessed via thermogravimetric analysis (TGA), show that TB-HPB-PIMs maintain robust thermal stability in nitrogen atmosphere, with tetra- and hexa-TB-HPBs leading the series. However, in oxidative environments, denser polymers such as TB-HPB and linear TB-polymer 1 demonstrate higher performance, likely due to restricted air diffusion. Overall, our findings highlight the critical need to balance porosity and thermal stability in TB-HPB-PIMs for applications in gas separation, carbon capture, and the potential for these polymers as flame retardant materials. Tetra-TB-HPB stands out as the most promising material for CO2 capture and thermal stability under inert conditions, while denser polymers like TB-HPB offer superior performance in oxidative environments.