Atomic charges are widely used to analyze molecular electronic structure and substituent effects, yet their numerical values and interpretations are inherently dependent on the adopted density partitioning scheme. Here, we adapt the Equivariant Atomic Contribution framework to molecular systems (EAC-qm), enabling prediction of atom-resolved continuous charge densities from which atomic charges are obtained as spatial moments. The predicted densities reproduce reference density functional theory results with high accuracy and preserve global charge conservation. To assess chemical interpretability, we examine charge responses in monosubstituted aromatic systems using Hammett substituent constants as external empirical references. Atomic charges derived from EAC-qm exhibit a strong linear association with Hammett parameters, compared with values obtained from traditional density partitioning approaches applied to the same electronic structures. These correlations indicate that density-derived charges respond systematically to established substituent electronic trends. Beyond scalar charges, atom-resolved dipole moments can be evaluated as first-order moments of the same continuous density representation. Illustrative examples for formaldehyde (H2CO) and formamide (HCONH2) show that local dipole vectors provide directional information about intra-atomic polarization that is not captured by point-charge models. Overall, the results suggest that machine-learned continuous electron densities provide a representation-consistent basis for constructing atom-centered electronic descriptors with chemical interpretability.

Porous Cu/Cu2O catalytic materials with a unique pore structure were successfully synthesized via a one-step solvothermal method using Cu-MOF-74 as the intermediate, followed by induced collapse and oxidation. The structural properties and catalytic performance of the as-prepared Cu/Cu2O materials in the thermal decomposition of ammonium perchlorate (AP) were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, and thermogravimetry–differential scanning calorimetry (TG-DSC) combined with in situ thermogravimetry–mass spectrometry (TG-MS). The results show that the specific surface area of the Cu/Cu2O material is 46.6697 m2/g, and the average pore diameter is 9.4608 nm. Owing to the synergistic effect of Cu0/Cu+ dual sites on promoting electron transfer during AP thermal decomposition, the Cu/Cu2O catalyst exhibits excellent catalytic activity. Specifically, at a heating rate of 20 °C/min, the addition of 2 wt% Cu/Cu2O reduces the high-temperature decomposition temperature of AP from 473.1 °C to 321.1 °C (a decrease of 151.0 °C), lowers the thermal decomposition activation energy from 296.63 kJ/mol to 253.21 kJ/mol (a reduction of 43.42 kJ/mol), and increases the heat release by 617.8 J/g compared to pure AP. TG-MS analysis revealed that Cu/Cu2O accelerates the decomposition of AP by adsorbing and activating NH3 and HClO4 generated in the low-temperature decomposition stage, facilitating the formation of reactive intermediates such as ClOₓ and promoting the oxidation of nitrogen-containing species. This study demonstrates that the porous Cu/Cu2O material synthesized by the one-step solvothermal method is a promising catalyst for enhancing the thermal decomposition performance of AP in solid propellants.

This study examines the activity coefficients of benzene, toluene, and di-(2-ethylhexyl)phosphoric acid (D2EHPA) in binary benzene–D2EHPA and toluene–D2EHPA systems, as well as the ternary n-hexane–toluene–D2EHPA system, using gas chromatography at 293.0 K. The primary objective was to determine UNIFAC model interaction parameters and validate their accuracy for predicting thermodynamic behavior in these systems. Experimental measurements revealed activity coefficient maxima for benzene and toluene at mole fractions of 0.8–0.9, decreasing to 0.46–0.67 in dilute solutions. The UNIFAC interaction parameters were calculated as follows: ACH–HPO4 (−334, 4605), ACCH3–HPO4 (680, 467), and refined CH2–HPO4 (54, 1199). The UNIFAC model achieved deviations of less than 2% from experimental data in both binary and ternary systems. A novel methodology incorporating intermediate standards for gas chromatography was developed to overcome challenges in measuring volatile solvent concentrations, enhancing measurement precision. These findings enable accurate prediction of activity coefficients in mixtures of alkanes, cycloalkanes, and monoaromatic hydrocarbons with D2EHPA, offering significant implications for optimizing metal liquid–liquid extraction processes.

The excessive use of tetracycline (TC) poses a severe threat to the health of humans and ecosystems. Environmentally friendly photocatalytic technology can be effectively used to degrade TC. In this study, an Fe-modified UIO-66 (Fe/UIO-66) catalyst was prepared via a solvothermal method. The structural and optical properties were investigated to elucidate how the electronic interaction between Fe and UIO-66 influenced the light absorption capacity of Fe/UIO-66. A xenon lamp was used to simulate sunlight, and TC was taken as the target pollutant. The results of photocatalytic experiments showed that the degradation efficiency of Fe/UIO-66 for TC reached 80% within 120 min, superior to that of UIO-66. In addition, the experiment also investigated the influence of inorganic salt ions on the catalytic performance, proving that Fe/UIO-66 could be applied for the efficient removal of TC in complex water bodies.

Activated carbons derived from coconut coir dust were synthesized via a two-step process combining carbonization and steam activation for application as electrode materials in supercapacitors. The influence of carbonization temperature (500–700 °C) on the morphological, structural, textural, and electrochemical properties of the resulting activated carbons was systematically investigated. Increasing the carbonization temperature led to a progressive collapse of the cellular structure and formation of a more compact and thermally stable carbon matrix, while the overall morphology remained largely unchanged after steam activation. The steam-activated carbon prepared from the carbonized sample at 700 °C (SA-CCD-7) exhibited the highest specific surface area (889 m2 g−1) and a well-developed hierarchical micro–mesoporous structure. Structural analyses confirmed the amorphous nature and an increase in structural disorder after activation, consistent with the enhanced pore development. Electrochemical measurements in 6 M KOH using a three-electrode system revealed that the SA-CCD-7 displayed a typical electric double-layer capacitor (EDLC) behavior, delivering the highest specific capacitance of 86 F g−1 at 1 A g−1 and retaining 81% of its initial capacitance at 20 A g−1, demonstrating excellent rate capability. The symmetric coin-cell supercapacitor device assembled with SA-CCD-7 as the electrodes achieved an energy density of 0.9–1.2 Wh kg−1 and a power density of 50–2500 W kg−1, along with remarkable cycling stability over 10,000 cycles with negligible capacitance loss. These findings highlight steam activation of coconut coir dust as a simple, scalable, and eco-friendly approach for producing biomass-derived carbon electrodes for sustainable energy storage applications.

Laminated polymer composites have emerged as a promising class of materials that provide exceptional mechanical and functional properties owing to multilayered architectures. In addition, additive manufacturing (AM) offers boundless opportunities to fabricate complex and intricate geometries with a wide variety of materials. Utilizing AM processes for producing laminated polymer composites can open new pathways for producing these intricate structures with fine control over geometry, layer thickness, and material distribution. In this study, we demonstrate the use of the stereolithography (SLA) process to fabricate laminated polymer composites to overcome the limitations of extrusion-based AM processes, i.e., challenges in high precision, strong interlayer bonding and uniform particle distribution. Photocurable polymer composites were prepared by adding different reinforcing particles, i.e., cobalt iron oxide (CoFe2O4), graphene (G), magnesium (Mg) and iron (II,III) oxide (Fe3O4), into the photocurable resin. Ultrasonication and mechanical mixing processes were used to prepare stable photocurable composites suitable for the SLA process. SLA process was also optimized, varying the process parameters (exposure time, bottom exposure time and bottom layer count) to achieve optimum dimensional accuracy and surface quality. Microscopic analysis confirmed the distinct and well-adhered composite layer sandwiched between the unfilled resin, validating the structural integrity of the multilayer design. Mechanical testing revealed significant improvement in the tensile properties of the laminated composites compared to pure resin, with resin/CoFe2O4 exhibiting 35.6% and 50.1% improvement in tensile strength and Young’s modulus compared to the pure resin, respectively. These results highlight the feasibility of SLA for producing multilayered polymer composites with improved mechanical performance and controlled architecture, broadening its potential for advanced engineering and biomedical applications.

To address the greenhouse effect and environmental pollution stemming from fossil fuels, the development of new energy sources is widely regarded as a critical pathway toward achieving carbon neutrality. Microalgae, as a feedstock for third-generation biofuels, have emerged as a research hotspot for producing biojet fuel due to their high photosynthetic efficiency, non-competition with food crops, and potential for carbon reduction. This paper provides a systematic review of technological advancements in the catalytic hydrogenation of microalgal oil for biojet fuel production. It specifically focuses on the reaction mechanisms and catalyst design involved in the hydrogenation–deoxygenation and cracking/isomerization processes within the Oil-to-Jet (OTJ) pathway. Furthermore, the paper compares the performance differences among various catalyst support materials and between precious and non-precious metal catalysts. Finally, it outlines the current landscape of policy support and progress in industrialization projects globally.

A straightforward synthetic method is advanced to produce hard-to-reach polycyclic compounds belonging to the [1,2,5]oxadiazolo[3,4-b]quinoxaline ring system. This approach draws on a combination of the nucleophilic aromatic substitution of hydrogen (SNH) and Scholl cross-coupling reactions, followed by reduction of the 1,2,5-oxadiazole fragment under mild reaction conditions. All compounds were obtained for the first time with moderate to excellent yields. Electrochemical and photophysical measurements show that the synthesized compounds may serve as narrow-band n-type organic semiconductors, with energy levels ranging from 2.00 to 2.28 eV, comparable to those of the best commercially available electronic semiconductors.

The goal of this study is to estimate the amount of lost data in electron microscopy and to analyze the extent to which experimentally acquired images are utilized in peer-reviewed scientific publications. Analysis of the number of images taken on electron microscopes at a core user facility and the number of images subsequently included in peer-reviewed scientific journals revealed low efficiency of data utilization. Up to around 90% of electron microscopy data generated during routine instrument operation can remain unused. Of the more than 150,000 electron microscopy images evaluated in this study, only approximately 3500 (just over 2%) were made available in publications. For the analyzed dataset, the amount of lost data in electron microscopy can be estimated as >90% (in terms of data being recorded but not being published in peer-reviewed literature). On the one hand, these results highlight a shortcoming in the optimal use of microscopy images; on the other hand, they indicate the existence of a large pool of electron microscopy data that can facilitate research in data science and the development of AI-based projects. The considerations important to unlock the potential of lost data are discussed in the present article.

Advancing catalysts for low-temperature NH3-SCR enhances their viability as a terminal flue gas denitration solution across diverse operating regimes. A high-performance, hydrothermally stable catalyst for low-temperature SCR was synthesized by depositing MnOx onto MgAlOx composite oxide supports. These supports, featuring varied Mg/Al ratios, originated from layered double hydroxide (LDH) precursors. The obtained catalyst with the Mg/Al ratio of 2 (Mn/Mg2AlOx) possesses relatively high concentrations of active oxygen species (Oα) and Mn4+ and exhibits remarkable catalytic performance. The Mn/Mg2AlOx catalyst exhibits a wide operating temperature range (100–300 °C) for denitration, achieving over 80% NOx conversion, along with robust water resistance. The temperature-programed surface reactions and NO oxidation reactions are performed to elucidate the promoting effect of water on N2 selectivity, which is not only due to inhibition of catalyst oxidation capacity at high temperature but also is related to the competing adsorption of water and NH3. In situ DRIFTS analysis confirmed that the NH3-SCR mechanism over Mn/Mg2AlOx adheres to the Eley–Rideal (E–R) pathway. These findings highlight the significant promise of Mn/MgAlOx catalysts for deployment as downstream denitration units within exhaust treatment systems.