Search Results (233)

Gibberellins (GAs) are essential phytohormones that regulate seed dormancy release and germination. Lomatogonium rotatum (L.) Fries ex Nym is a traditional medicinal plant whose seed germination is often hindered by physiological dormancy. In this study, we systematically investigated the effects of exogenous GA₃ on the seed germination of L. rotatum and elucidated the underlying molecular regulatory mechanisms via transcriptomic analysis. GA₃ treatment (500 mg/L for 24 h) significantly improved the germination rate, vigor index, and other germination traits. RNA-seq analysis identified time-dependent transcriptional changes in GA₃-treated seeds across three developmental stages (24 h, 72 h, and 96 h). KEGG enrichment and K-means clustering revealed dynamic actiSvation of hormonal signaling, secondary metabolism, and DNA replication pathways. WGCNA uncovered two hormone-responsive co-expression modules (Red and Lightcyan) corresponding to early and late stages of germination, respectively. Key genes related to ABA and GA biosynthesis and signal transduction showed phase-specific expression, highlighting the coordinated hormonal regulation during seed germination. Our findings provide new insights into the molecular basis of GA₃-regulated seed germination and offer theoretical support for the cultivation and utilization of L. rotatum. Full article

The initial surface reaction of gallium nitride (GaN) grown by atomic layer deposition (GaN-ALD) was investigated using density functional theory (DFT) calculations. Trimethylgallium (TMG) and ammonia (NH₃) were used as gallium (Ga) and nitrogen (N) precursors, respectively. DFT calculations at the B3LYP/6-311+G(2d,p) and 6-31G(d) levels were performed to compute relative energies and optimize chemical structures, respectively. TMG adsorption on Si₁₅H₁₈–(NH₂)₂ and Si₁₅H₂₀=(NH)₂ clusters was modeled, where –NH₂ and =NH surface species served as adsorption sites. The reaction mechanisms in the adsorption and nitridation steps were investigated. The results showed that TMG can adsorb on both surface adsorption sites. In the initial adsorption stage, TMG adsorbs onto =NH- and –NH₂-terminated Si(100) surfaces with activation energies of 1.11 and 2.00 eV, respectively, indicating that the =NH site is more reactive. During subsequent NH3 adsorption, NH₃ adsorbs onto the residual TMG on the =NH- and –NH₂-terminated surfaces with activation energies of approximately 2.00 ± 0.02 eV. The reaction pathways indicate that NH₃ adsorbs via similar mechanisms on both surfaces, resulting in comparable nitridation kinetics. Furthermore, this study suggests that highly reactive NH₂⁻ species generated in the gas phase from ionized NH₃ may help reduce the process temperature in the GaN-ALD process. Full article

Two-phase expansion processes have emerged as a promising technology for enhancing energy efficiency in power generation, refrigeration, waste heat recovery systems (for example, partially evaporated organic Rankine cycle, organic flash cycle, and trilateral flash cycle), oil and gas, and other applications. However, despite their potential, widespread adoption is hindered by inherent challenges, particularly energy losses that reduce operational efficiency. This review systematically evaluates the current state of two-phase expansion technologies, focusing on the root causes, impacts, and mitigation strategies for expansion losses. This work used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Using the PRISMA framework, 52 relevant publications were identified from Scopus and Web of Science to conduct the systematic review. A preliminary co-occurrence analysis of keywords was also conducted using VOSviewer version 1.6.20. Three clusters were observed in this co-occurrence analysis. However, the results may not be significant. Therefore, the extended work was done through a comprehensive analysis of experimental and simulation studies from the literature. This study identifies critical loss mechanisms in key components of two-phase expanders, such as the nozzle, diffuser, rotor, working chamber, and vaneless space. Also, losses arising from wetness, such as droplet formation, interfacial friction, and non-equilibrium phase transitions, are examined. These phenomena degrade performance by disrupting flow stability, increasing entropy generation, and causing mechanical erosion. Several losses in the turbine and volumetric expanders operating in two-phase conditions are reported. Ejectors, throttling valves, and flashing flow systems that exhibit similar challenges of losses are also discussed. This review discusses the mitigation and the strategy to minimize the two-phase expansion losses. The geometry of the inlet of the two-phase expanders plays an important role, which also needs improvement to minimize losses. The review highlights recent advancements in addressing these challenges and shows optimization opportunities for further research. Full article

In this study, density functional theory (DFT) was used to analyze the processes that govern the interactions among triethylaluminum (TEAL), the Ziegler–Natta (ZN) catalyst, and the inhibitory compounds dimethylamine (DMA) and diethylamine (DEA) during olefin polymerization. The structural and charge characteristics of these inhibitors were examined through steric maps and DFT calculations. Combined DFT calculations (D3-B3LYP/6-311++G(d,p)) and IR spectroscopic analysis show that the most efficient way to deactivate the ZN catalyst is via the initial formation of the TEAL·DMA complex. This step has a kinetic barrier of only 27 kcal mol⁻¹ and a negative ΔG, in stark contrast to the >120 kcal mol⁻¹ required to form TEAL·DEA. Once generated, TEAL·DMA adsorbs onto the TiCl₄/MgCl₂ cluster with adsorption energies of −22.9 kcal mol⁻¹ in the gas phase and −25.4 kcal mol⁻¹ in n-hexane (SMD model), values 5–10 kcal mol⁻¹ more favorable than those for TEAL·DEA. This explains why, although dimethylamine is present at only 140 ppm, its impact on productivity (−19.6%) is practically identical to that produced by 170 ppm of diethylamine (−20%). The persistence of the ν(Al–N) band at ~615 cm⁻¹, along with a >30% decrease in the Al–C/Ti–C bands between 500 and 900 cm⁻¹, the downward shift of the N–H stretch from ~3300 to 3200 cm⁻¹, and the +15 cm⁻¹ increase in ν(C–N) confirm Al←N coordination and blockage of alkyl transfer, establishing the TEAL·DMA → ZN pathway as the dominant catalytic poisoning mechanism. Full article

This study examines how the Russia–Ukraine conflict has affected the robustness of the global liquefied natural gas (LNG) trade network—an essential component of the global energy transition. As environmental concerns intensify worldwide, LNG is gaining strategic importance due to its cleaner emissions and greater flexibility compared to traditional fossil fuels. However, the global LNG trade network remains vulnerable to geopolitical shocks, particularly due to its concentrated structure. In this context, we construct the LNG trade network from 2020 to 2023 and employ complex network analysis to explore its structural characteristics. We assess network robustness under various attack strategies, budget constraints, and phases of the conflict. Furthermore, we utilize the difference-in-differences (DID) method to evaluate the conflict’s impact on network robustness. Our findings reveal that the global LNG trade network exhibits a distinct center–periphery structure and regional clustering. Although the network scale has continuously expanded, its connectivity still requires improvement. The Russia–Ukraine conflict has significantly weakened network robustness, with negative impacts intensifying across attack phases and under greater budget constraints. The optimal attack strategy causes the most severe degradation, followed by high-importance attacks, while random and low-importance attacks exert limited influence. Our DID-based analysis further confirms the conflict’s significant negative impact. To strengthen its resilience, the global LNG trade network should diversify its partnerships and invest in infrastructure enhancements. Full article

Wuyi Shuixian tea, a premium oolong tea known for its complex floral-fruity aroma, exhibits significant quality variations across different grades. This study systematically analyzed the aroma characteristics and key fragrant compounds of four grades (Grand Prize SA, First Prize SB, Outstanding Award SC, and Non-award SD) using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV) analysis, and multivariate statistical methods. A total of 159 volatile compounds were identified, with similar compound categories but distinct concentration gradients between grades. OAV-splitting analysis (based on OAV ≥ 1 as the threshold for aroma activity) identified β-ionone (fruity), octanal (fatty), and linalool (floral) as core aroma-active contributors, as their OAV values significantly exceeded 10 in awarded grades (SA, SB, SC), indicating dominant roles in sensory perception. Notably, linalool, a floral marker, showed a concentration gradient (SA > SB > SC) and was absent in SD, serving as a critical determinant of grade differentiation. Orthogonal partial least squares-discriminant analysis (OPLS-DA) further distinguished awarded grades (SA, SB, SC) by balanced fruity, floral, and woody notes, while SD lacked floral traits and exhibited burnt aromas. This classification was supported by hierarchical clustering analysis (HCA) of volatile profiles and principal component analysis (PCA). Electronic nose data validated these findings, showing strong correlations between sensor responses (W5S/W2W) and key compounds like hexanal and β-ionone. This study elucidates the molecular basis of aroma-driven quality grading in Wuyi Shuixian tea, providing a scientific framework for optimizing processing techniques and enhancing quality evaluation standards. The integration of chemical profiling with sensory attributes advances precision in tea industry practices, bridging traditional grading with objective analytical metrics. Full article

Various volatile compounds are responsible for the odor changes in fish during storage. In this study, a coupled headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC-MS) analytical approach was applied to characterize the volatile compounds in large yellow croaker (Pseudosciaena crocea) during storage under three treatments: cold storage (CS), slurry ice (SI), and crushed ice (CI). A total of 24 volatile substances were identified, including aldehydes, ketones, and alcohols. Multivariate statistical analyses (PCA, PLS-DA, VIP, and cluster heatmap) revealed significant differences in volatile compounds between the treatment groups during storage, and 10 key volatiles along with 5 potential biomarker compounds were identified. The underlying mechanisms of volatile changes were further investigated by analyzing three key pathways: thermal reactions, lipid oxidation, and amino acid degradation. Notably, SI treatment better avoid volatile compound variation in large yellow croaker. Full article

PM₁₀ samples were collected at an urban site of Zhuozhou, the southern gateway of Beijing, from 28 December 2021 to 29 January 2022, in order to explore the chemical composition, sources and physical and chemical formation processes of prominent components. The results showed that five trace elements (Mn, Cu, As, Zn and Pb) had high enrichment in PM₁₀ and were closely related with anthropogenic combustion and vehicle emissions; organic and element carbon had a high correlation due to the same primary sources and similar evolution; nitrate dominated SNA (sulfate, nitrate, ammonium) and nitrate/sulfate ratios reached 2.35 on the polluted days owing to the significant contribution of motor vehicle emissions. Positive matrix factorization analysis indicated that secondary source, traffic, biomass burning, industry, coal combustion and crustal dust were the main sources of PM₁₀, contributing 32.5%, 20.9%, 15.0%, 13.9%, 9.4% and 8.3%, respectively; backward trajectories and potential source contribution function analysis showed that short-distance airflow was the dominant cluster and accounted for nearly 50% of total trajectories. The Weather Research and Forecasting model with Chemistry, with integrated process rate analysis, showed that dominant gas-phase reactions (heterogeneous reaction) during daytime (nighttime) in presence of ammonia led to a significant enhancement of nitrate in Zhuozhou, contributing 12.6 μg/m³ in episode 1 and 22.9 μg/m³ in episode 2. Full article

Molybdenum nitrides are known to have a series of excellent physical properties owing to their unique bonding nature and electronic structure. However, the synthesized samples often exist in nonstoichiometric phases with structural defects (metal or non-metal vacancies), which may influence their performance. Based on the density functional theory, we theoretically studied the vacancy formation in δ-MoN. Various configurations that contained one single vacancy, divacancies, or trivacancies were constructed and systematically studied. It was found that Mo vacancy leads to significant electron loss at the vacant site while N vacancy results in excess electrons being trapped, forming a uniform electron gas region. Detailed analysis revealed that four types of binding clusters are encouraged to form in δ-MoN. The V_Mo–V_N or V_N–V_Mo–V_N (with a sandwich structure) binding is owing to the positive and negative interaction between Mo and N vacancies. The V_N–V_N or V_N–V_N–V_N binding is attributed to the overlap of electron density, but requires N vacancies to be distributed in a specific arrangement. Both Mo and N vacancies induce the anisotropic degradation of electronic conductivity in δ-MoN, with the extent of degradation governed by the vacancy type and concentration. Full article

Solar interface evaporation is a promising technology for sustainable freshwater acquisition. Regulating the hydrophilicity/hydrophobicity of the evaporator can optimize the water transport, heat transfer, and evaporation enthalpy during the evaporation process, thereby significantly improving the evaporation performance. The CoSe/Co-SeC nanoflower was prepared by high-temperature selenization of ZIF-67. Each petal of the nanoflower is loaded with a density-gradient distribution CoSe/Co, forming an uneven hydrophilic and hydrophobic surface that transitions from bottom hydrophilicity to top hydrophobicity. During the evaporation process, the hydrophilic bottom of the petals promotes rapid water supply, while the hydrophobic top of the petals protrudes from the water surface to form a large number of solid–liquid–gas three-phase interfaces. Therefore, water clusters activated by the strong hydrophilic sites at the bottom of the petals can reach the gas–liquid interface after a very short transmission distance and achieve water cluster evaporation. In addition, the nanoflower optimized the heat transfer at the solid–liquid interface and further promoted the increase in evaporation rate through micro-meniscus evaporation (MME). As a result, the evaporation rate and energy efficiency of the CoSe/Co-SeC evaporator are as high as 2.44 kg m⁻² h⁻¹ and 95.5%. This work passes controllable preparation of the gradient CoSe/Co-SeC and shows the enormous potential of micro-hydrophobic and hydrophilic regulation for improving solar interface evaporation performance. Full article

The process of formation of composite systems based on nanosilica A-300 and biologically active substances (BAS), namely gallic acid (GA), glycyrrhizic acid (GLA), and its salts, was studied using a set of physicochemical methods. It was shown that when BAS are immobilized on the silica surface by the method of joint grinding in a porcelain mortar, they pass into a nanosized X-ray amorphous state. Water adsorbed on the surface of such composite systems is also in a clustered state, and the radius of adsorbed water clusters is in the range of 0.4–50 nm. The chloroform environment has a complex effect on the size of water clusters. In general, there is a tendency for the radius of water clusters to increase when air is replaced by a chloroform environment. However, this does not always lead to a decrease in the interfacial energy. The possibility of the existence of metastable ice in the temperature range up to 287 K, stabilized by the surface of composite systems, was discovered. The amount of such ice can reach 20% of the total water content in the sample. The possibility of using complex viscosity measurements for hydrated silica powders and silica containing immobilized biologically active substances was shown. These measurements allow recording changes in the phase state of complex mixtures during the formation of compact composite forms under the influence of periodic mechanical loading. Full article

A detailed characterization of metal clusters bound at the surface of crystalline metal oxide supports is crucial for identifying their structure–property relationships relevant to practical applications. Theoretical investigations based on first-principles calculations have proven to be helpful in characterizing supported metal clusters. In this work, the adsorption of an Sn dimer on the regular and defective (100) surfaces of MgO crystal was studied by means of density functional theory (DFT) calculations. The investigated defects included ${\mathrm{F}}_{\mathrm{s}}^0$, ${\mathrm{F}}_{\mathrm{s}}^{+}$, and ${\mathrm{F}}_{\mathrm{s}}^{2+}$ oxygen vacancies on MgO(100). From the results of the calculations, it is clear that the adsorption of Sn₂ at the ${\mathrm{F}}_{\mathrm{s}}^0$ and ${\mathrm{F}}_{\mathrm{s}}^{+}$ centers is stronger than that occurring on the defect-free MgO(100) surface. While the triplet spin multiplicity of a free Sn dimer tends to be preserved upon its adsorption at the ${\mathrm{F}}_{\mathrm{s}}^{2+}$ center, spin quenching is favored for the dimer adsorbed at the regular O²⁻ and defective ${\mathrm{F}}_{\mathrm{s}}^0$ and ${\mathrm{F}}_{\mathrm{s}}^{+}$ centers. The topological analysis of the electron density for the adsorbed dimer was carried out within the quantum theory of atoms in molecules (QTAIM). The calculated values of QTAIM parameters for the Sn-Sn bond of the adsorbed dimer do not differ radically from the corresponding values for the dimer in the gas phase. Full article

The bagging technique is a traditional preharvest practice used in Vinalopó Bagged Table Grape production to improve fruit quality and protect clusters from environmental stress. However, its influence on grape volatile composition remains underexplored. This study analyzed the volatile profile of three grape varieties (‘Dominga’, ‘Aledo’, and ‘Doña María’) by comparing bagged and non-bagged clusters to assess the effect of bagging on aromatic compounds. Volatiles were extracted using headspace solid-phase microextraction (HS-SPME) and analyzed by gas chromatography–mass spectrometry (GC–MS). A total of 35 volatile compounds were identified and quantified, mainly aldehydes, terpenes, and alcohols. The highest concentration was found in non-bagged ‘Dominga’ grapes (57.17 mg kg⁻¹), and the lowest in bagged ‘Doña María’ grapes (16.36 mg kg⁻¹). Although total volatile content did not differ significantly between treatments, differences were observed in the relative abundance of chemical families. Bagged grapes showed higher proportions of aldehydes, such as hexanal and (E)-2-hexenal, contributing to green, fresh aromas, while non-bagged grapes exhibited more alcohols and esters, linked to fruity and overripe notes. This study offers new insights into the role of preharvest bagging in shaping grape volatile composition, contributing to a better understanding of its impact on fruit aroma and quality. Full article

This study presents a novel unresolved SPH-DEM coupling framework to investigate the complex interactions between rising gas bubbles and sinking solid particles in multiphase systems. Traditional numerical methods often struggle with large deformations, multiphase interfaces, and computational efficiency when simulating dense particle-laden flows. To address these challenges, the proposed model leverages SPH’s Lagrangian nature to resolve fluid motion and bubble dynamics, while the DEM captures particle–particle and particle–bubble interactions. An unresolved coupling strategy is introduced to bridge the scales between fluid and particle phases, enabling efficient simulations of large-scale systems with discrete bubbles/particles. The model is validated against benchmark cases, including single bubbles rising and single particle’s sedimentation. Simulation studies reveal the effects of particle/bubble number and initial distance on phase interaction patterns and clustering behaviors. Results further illustrate the model’s capability to capture complex phenomena such as particle entrainment by bubble wakes and hindered settling in dense suspensions. The framework offers a robust and efficient tool for optimizing industrial processes like mineral flotation, where bubble–particle dynamics play a critical role. Full article

Rice hulls, a traditional ingredient in Chinese light-flavor Baijiu, contribute to bran and furfural flavors but may adversely affect the aroma and taste. This study explores fresh pomegranate peel as a sustainable alternative to rice hulls in Baijiu fermentation. The flavor profiles in jiupei and Baijiu were interpreted by employing head-space solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), while their physicochemical characteristics were systematically assessed. Statistical evaluations, such as correlation analysis and cluster analysis, were conducted to interpret the data. The results showed that compared with rice hull, pomegranate peel reduced furfural content in jiupei by 90%, increased the alcohol distillation rate (alcohol distillation rate: this refers to the weight percentage of 50% alcohol by volume (ABV) Baijiu produced from a unit amount of raw material under standard atmospheric pressure at 20 °C (also known as Baijiu yield)) by 30%, enhanced antioxidant capacity by 24.38%, and improved starch efficiency by 3%. Notably, the Baijiu complied with the premium Baijiu standards specified in the Chinese National Standard for light-flavor Baijiu. Additionally, under the experimental conditions of this study, the optimal Baijiu yield (optimal Baijiu yield: the maximum achievable Baijiu production under defined constraints (e.g., energy input, time, cost)) (48% ± 3.41%) correlated with the pomegranate peel particle size. This research highlights the viability of using pomegranate peel as a sustainable and environmentally friendly adjunct in the fermentation of light-flavor Baijiu, offering valuable perspectives for exploring alternative brewing ingredients. Full article