Formation Mechanism Research Articles

Separation of ovomucin from duck egg white and its “acid-tight /alkali-loose” self-supporting gel properties under different pH

Ovomucin is a key component in maintaining the viscous nature of egg white and has vast potential in the utilization of food industry. The objectives of the study were to determine the effect of different pH on the extractability and gel properties of ovomucin. After removing lysozyme through ion exchange, the diluted duck egg white was acidified to a narrow pH range (4.50, 4.75, 5.00, 5.25, 5.50, 5.75 and 6.00) to precipitate ovomucin. By comprehensive study of purity, yield, and convenience of large-scale preparation, 4.75 was chosen as the optimal pH to extract ovomucin with the highest purity of 85.17 ± 2.31% and a compromised yield of 4.60 ± 0.06 mg/g duck egg white. A series of self-supporting gels were prepared with freeze-dried ovomucin powder at room temperature upon rehydration and centrifugation, and the gels properties were highly associated with pH. Gel formed around pH 5 was the aggregate of natural globular proteins with lowest hydrophobicity and electrostatic interaction, relatively dense structure and high water-holding capacity (WHC). Stronger acidic conditions disrupted the disulfide bonds and formed a rougher spherical aggregate. Under alkaline conditions, however, the protein gradually unfolded and broke into linear basic polypeptides, thus a porous three-dimensional network was formed. Overall, this study provided insights into the formation mechanism of the “acid-tight/alkali-loose” ovomucin gels, and introduced a potential candidate for the development of bioactive substance delivery materials.

Global Climatology of Low‐Level‐Jets: Occurrence, Characteristics, and Meteorological Drivers

AbstractLow‐level jets (LLJs), vertical profiles with a wind speed maxima in the lowest hundred meters of the troposphere, have multiple impacts in the Earth system, but a global present‐day climatology based on contemporary data does not exist. We use the spatially and temporally complete data set from ERA5 reanalysis to compile a global climatology of LLJs for studying the formation mechanisms, characteristics, and trends during the period of 1992–2021. In the global mean, LLJs are detected 21% of the time with more cases over land (32%) than over the ocean (15%). We classified the LLJs into three categories: non‐polar land (LLLJ), polar land (PLLJ), and coastal (CLLJ) LLJs. For LLLJ, the averaged frequency of occurrence is 20% and 75% of them are associated with a near‐surface temperature inversion as a prerequisite for an inertial oscillation. PLLJs are also associated with a temperature inversion and occur even more frequently with 59% of the time. These are also the lowest and the strongest LLJs among the three categories. CLLJs are particularly frequent in some marine hotspots, situated along the west coast of continents, with neutral to unstable stratification close to the surfaces and a stably stratified layer aloft. We found distinct regional trends in both the frequency and intensity of LLJs over the past decades, which can have implications for the emission and transport of aerosols, and the transport of atmospheric moisture. Future studies could address changes in LLJs and the associated implications in more detail, based on the here released ERA5‐based LLJ data.

Transglutaminase-crosslinked cold-set pea protein isolate gels modified by pH shifting: Properties, structure and formation mechanisms

The poor gelation properties of pea protein isolate (PPI) limit their use in food industries. In the present study, PPI was modified by pH-shifting combined with heat treatment, followed by cold-set gelation of PPI gels induced by transglutaminase. Both pH 2–3 and pH 10–12 promoted the unfolding of PPI molecules and the transformation of secondary structures from ordered to disordered. In particular, PPI molecules with pH 12-shifting tended to expand and unfold, which resulted in the exposure of internal active groups and improvement in surface hydrophobicity. Accordingly, after the addition of 50 U/g transglutaminase, PPI gels with pH 12-shifting and heating treatment exhibited homogeneous and dense gel network with high cross-linking degree (88.12 ± 1.80%) and water holding capacity (92.13 ± 2.40%), since pH 12-shifting and heating treatment promoted the conversion of random coils and β-turns to β-folds and α-helices in PPI gels. However, with pH 10 and 11-shifting, the PPI molecules was partially unfolded and the PPI gels had a high non-network protein content, resulting in low-strength gel networks of PPI gels with rough and loose microstructures and a low WHC. These results showed that TGase-crosslinked cold-set PPI gels after pH 12-shifting and heat treatment could promote the formation of homogeneous and dense gel network structure, so that improved the PPI gelation properties, which had great potential to be used as gelling agents or nutraceutical delivery systems for thermal sensitive bioactive compounds in food and non-food fields.

Ekman-driven salt transport as a key mechanism for open-ocean polynya formation at Maud Rise.

Open-ocean polynyas formed over the Maud Rise, in the Weddell Sea, during the winters of 2016-2017. Such polynyas are rare events in the Southern Ocean and are associated with deep convection, affecting regional carbon and heat budgets. Using an ocean state estimate, we found that during 2017, early sea ice melting occurred in response to enhanced vertical mixing of heat, which was accompanied by mixing of salt. The melting sea ice compensated for the vertically mixed salt, resulting in a net buoyancy gain. An additional salt input was then necessary to destabilize the upper ocean. This came from a hitherto unexplored polynya-formation mechanism: an Ekman transport of salt across a jet girdling the northern flank of the Maud Rise. Such transport was driven by intensified eastward surface stresses during 2015-2018. Our results illustrate how highly localized interactions between wind, ocean flow and topography can trigger polynya formation in the open Southern Ocean.

Elucidating the Mechanism of Tetrahydrofuran-Diol Formation through Os(VI)-Catalyzed Oxidative Cyclization of 5,6-Dihydroxyalkenes Ligated by Citric Acid.

A computational study is reported here on the mechanism of tetrahydrofuran (THF)-diol formation from the Os(VI)-catalyzed oxidative cyclization of 5,6-dihydroxyalkene ligated with citric acid and in the presence of Bro̷nsted acid. Initiated by Os(VI) dioxo citrate formation, coordination of co-oxidant pyridine-N-oxide (PNO) and protonation of its oxo group generate the active catalyst. The catalytic cycle commences through successive steps, including dihydroxyalkene addition to the active catalyst in a concerted mechanism to form hexacoordinated alkoxy-protonated PNO-complexed Os(VI) bisglycolate as a turnover-limiting step (TLS), cyclization to Os(IV) THF-diolate, reoxidation to Os(VI) THF-diolate, and hydrolysis via a dissociative mechanism to furnish the THF-diol and regenerate the active species, sustaining the catalytic cycle through an Os(VI)/Os(IV) cycle. Despite the overall exergonic nature of catalytic cycle (ΔGrcycle = -45.0 kcal/mol), the TLS is accelerated by the formation of an open-valence 16-electron Os(VI) intermediate but decelerated by the undesired formation of a saturated/hexacoordinate 18-electron Os(VI) intermediate. Bro̷nsted acid plays crucial roles in the formation of Os(VI) citrate and the active catalyst, impediment of the second cycle, and the cyclization step. Additionally, besides its role as a co-oxidant, and in the presence of acid, PNO is found to assist the insertion of dihydroxyalkene and, importantly, in releasing the THF-diol to regenerate the active intermediate.

Mechanism of WS2 Nanotube Formation Revealed by in Situ/ex Situ Imaging.

Multiwall WS2 nanotubes have been synthesized from W18O49 nanowhiskers in substantial amounts for more than a decade. The established growth model is based on the "surface-inward" mechanism, whereby the high-temperature reaction with H2S starts on the nanowhisker surface, and the oxide-to-sulfide conversion progresses inward until hollow-core multiwall WS2 nanotubes are obtained. In the present work, an upgraded in situ SEM μReactor with H2 and H2S sources has been conceived to study the growth mechanism in detail. A hitherto undescribed growth mechanism, named "receding oxide core", which complements the "surface-inward" model, is observed and kinetically evaluated. Initially, the nanowhisker is passivated by several WS2 layers via the surface-inward reaction. At this point, the diffusion of H2S through the already existing outer layers becomes exceedingly sluggish, and the surface-inward reaction is slowed down appreciably. Subsequently, the tungsten suboxide core is anisotropically volatilized within the core close to its tips. The oxide vapors within the core lead to its partial out-diffusion, partially forming a cavity that expands with reaction time. Additionally, the oxide vapors react with the internalized H2S gas, forming fresh WS2 layers in the cavity of the nascent nanotube. The rate of the receding oxide core mode increases with temperatures above 900 °C. The growth of nanotubes in the atmospheric pressure flow reactor is carried out as well, showing that the proposed growth model (receding oxide core) is also relevant under regular reaction parameters. The current study comprehensively explains the WS2 nanotube growth mechanism, combining the known model with contemporary insight.

Matrix metalloproteinase Nas15 regulates the lumen formation and expansion in Ciona notochord

Lumen formation, as a key process of biological tube construction, is essential in various physiological processes such as nutrient and waste transporting, gas exchanging, and structural supporting. However, the mechanisms underlying tubular lumen development are still not fully understood. In the present study, we identified a matrix metalloproteinase, Nas15, which is enriched in the apical domain of the Ciona embryonic notochord. The expression level of the Nas15 gene significantly increased during notochord lumen formation and expansion. Nas15 loss-of-function resulted in abnormal notochord lumen expansion in Ciona embryos. Besides, yeast two-hybrid screening and CO-IP results indicated a Phosphatase 2 Catalytic Subunit Alpha (PPP2CA) physically interacted with Nas15. PPP2CA also involved in notochord lumen formation via localizing Nas15. Furthermore, we investigated the distribution of laminin in Nas15 disrupted embryos. In conclusion, our results revealed a mechanisms of how notochord cells regulating lumen expansion via metalloproteinase-mediated ECM localization. This findings provide insight into the mechanisms of tubular organ lumen formation and serve as a reference for research on human abnormal lumenogenesis diseases.

Research on the Influencing Factors of the Value of Listed Companies under the New Economic Environment

This paper explores the influencing factors of the value of listed companies in the new economic environment, aiming to deepen the understanding of the formation mechanism of the value of listed companies in the ever-changing economic environment. Firstly, the article analyzes the characteristics of listed companies under the new economic environment and the impact of the new economy on enterprises, including technological innovation, changes in market competition patterns, and so on. Secondly, the paper elaborates on the theoretical framework of the value of listed companies, including the concept of value, influencing factors, and evaluation methods. Finally, the article delves into the influencing factors of the value of listed companies in the new economic environment, including technological factors, innovation capability, industrial environment, and corporate governance. Through the analysis of these factors, this paper provides important theoretical references and practical guidance for understanding and evaluating the value of listed companies in the new economic era.

DFT and AIMD insights into heterogeneous dissociation of 2-chlorothiophenol on CuO(111) surface: Impact of H2O and OH

Copper oxides are vital catalysts in facilitating the formation of polychlorinated thianthrenes/dibenzothiophenes (PCTA/DTs) through heterogeneous reactions in high-temperature industrial processes. Chlorothiophenols (CTPs) are the most crucial precursors for PCTA/DT formation. The initial step in this process is the metal-catalyzed production of chlorothiophenoxy radicals (CTPRs) from CTPs via dissociation reactions. This work combines density functional theory (DFT) calculations with ab initio molecular dynamics (AIMD) simulations to explore the formation mechanism of the adsorbed 2-CTPR from 2-CTP, with the assistance of CuO(111). Our study demonstrates that flat adsorption configurations of 2-CTP on the CuO(111) surface are more stable than vertical configurations. The CuO(111) surface acts as a strong catalyst, facilitating the dissociation of 2-CTP into the adsorbed 2-CTPR. Surface oxygen vacancies enhance the adsorption of 2-CTP on the CuO(111) surface, while moderately suppressing the dissociation of 2-CTP. More importantly, water molecules and surface hydroxyl groups actively promote the dissociation of 2-CTP. Specifically, water directly participates in the reaction through “water bridge”, enabling a barrier-free process. This research provides molecular-level insights into the heterogeneous generation of dioxins with the catalysis of metal oxides in fly ash from static and dynamic aspects, providing novel approaches for reducing dioxin emissions and establishing dioxin control strategies.

Progressive expansion of albumin adducts for organophosphorus nerve agent traceability based on single and group adduct collection.

Protein adducts are important biological targets for traceability of organophosphorus nerve agents (OPNAs). Currently, the recognized biomarkers that can be used in actual samples in the field of chemical forensics only include Y411 in albumin and the active nonapeptide in butyrylcholinesterase (BChE). To explore stable and reliable protein adducts and increase the accuracy of OPNAs traceability further, we gradually expanded OPNAs-albumin adducts based on single and group adduct collection. Several stable peptides were found via LC-MS/MS analysis in human serum albumin (HSA) exposed to OPNAs in a large exposure range. These adducts were present in HSA samples exposed to OPNAs of each concentration, which provided data support for the reliability and stability of using adducts to trace OPNAs. Meanwhile, the formation mechanism of OPNAs-cysteine adduct was clarified via computer simulations. Then, these active sites foundand modified peptides were used as raw materials for progressive expansion of albumin adducts. We constructed an OPNAs-HSA adducts group, in which a specific agent is the exposure source, and three or more active peptides constitute data sets for OPNAs traceability. Compared with single or scattered protein adducts, the OPNAs-HSA adduct group improves OPNAs identification by mutual verification using active peptides or by narrowing the identity range of theexposure source. We also determined the minimum detectable concentration of OPNAs for the adduct group. Two or more peptides can be detected when there is an exposure of 50 times the molar excess of OPNAs in relation to HSA. This improved the accuracy of OPNAs exposure and identity confirmation. A collection of OPNAs-albumin adducts was also examined. The collection was established by collecting, classifying, and integrating the existing albumin adducts according to the species to which each albumin belongs, the types of agents, and protease. This method can serve as a reference for discovering new albumin adducts, characteristic phosphonylated peptides, and potential biomarkers. In addition, to avoid a false negative for OPNAs traceability using albumin adducts, we explored OPNAs-cholinesterase adducts because cholinesterase is more reactive with OPNAs than albumin. Seven active peptides in red blood cell acetylcholinesterase (RBC AChE) and serum BChE can assist in OPNAs exposure and identity confirmation.

Optimal collimation of proton beams accelerated by a Laguerre–Gaussian laser with a proper pulse duration

In this study, three-dimensional particle-in-cell (PIC) simulations were conducted to evaluate a collimated proton beam accelerated by an intense Laguerre–Gaussian (LG) laser with different pulse durations. The flux and energy of the collimated proton beam could be simultaneously enhanced by selecting an optimal pulse duration. This phenomenon can be primarily attributed to the correlation between the LG laser driven self-generated magnetic field and pulse duration, and this correlation enables the collimation of protons during their interaction and transport. The results obtained in this study elucidate the formation mechanism of different collimated proton patterns, driven by femtosecond and picosecond LG lasers, observed in previous experiments. In addition, based on these results, an optimum pulse duration for high-quality proton beams is proposed for various future applications.

Self‐assembly of Polyoxometalate Clusters into Nanostructures with Different Dimensions

Self‐assembly of polyoxometalate (POM) clusters offers a viable method for constructing nanostructures with tailored properties. Over the past few decades, POMs‐based nanostructures of varying dimensions, such as nanowires, nanobelts, nanosheets, and other superstructures, have been constructed. Additionally, these nanostructures show broad prospects in optical, electrochemical, catalytic, and mechanical applications. Particularly noteworthy are surface modifications, such as surfactant encapsulation, which yield amphiphilic POMs. These modifications render the POMs compatible with organic systems, significantly broadening their morphological and functional applicability. This concept provides an overview of recent advancements in nanostructures based on self‐assembly of surfactant encapsulated POM clusters, encompassing one‐dimensional (1D), two‐dimensional (2D), and three‐dimensional (3D) structures. Through surfactant encapsulation, POM clusters can be rendered compatible with various solvents, facilitating the formation of hybrid assemblies with diverse morphologies and unique properties. The structures, formation mechanisms, and properties of these sub‐nanometer assemblies are discussed from both experimental and theoretical perspectives. This concept aims to provide a new insight into the design and fabrication of nanostructures based on POM clusters.

Formation mechanism and evolution of interfacial residual stress between composite propellant and rubber liner during curing process

This study focuses on the solid rocket engines, which are commonly used in satellite launches and space exploration. The residual stress at the interface between the composite propellant and rubber liner generated during the curing process can lead to several issues, such as debonding, shrinkage, and deformation. This study aims to examine the mechanism and evolution law of the residual stress development. A finite element model is established to examine the residual stress during the full curing process. The composite propellant undergoes intricate temperature and curing gradients. The stress in various parts of the propellant and liner is monitored throughout the entire curing cycle. The propellant's temperature exhibits a delayed response during the heating and cooling phases of the curing process. The interface undergoes curing throughout the stage of constant temperature, with its chemical shrinkage primarily taking place prior to the cooling step. Considerable stress exists at the contact before cooling. The stress caused by thermal influences becomes more noticeable during the cooling phase. The influence of propellant composition and curing process parameters on interface stress is investigated. In addition, a specific vision-based device is innovatively designed to monitor deformation changes during the curing process. The key parameters of the simulation are optimized by combining the detected deformation, aiming to minimize the deformation difference between the experiment and the simulation, so as to realize the corresponding stress evaluation. The measurement results show an average deformation error of 10.71% and an average stress error of 10.58%.

Dynamic wetting performance and resin-flow behavior of two-level selective laser-etched metal surface in resin transfer moulding process of fiber-metal laminates

ABSTRACT In selective laser etching for the interfacial strengthening of Fiber Metal Laminates (FMLs), the wettability of customized structured features significantly affects their overall mechanical properties. For two-level features, their complicated geometry makes the evaluation of wettability difficult, which introduces challenges to feature design. In this study, a sandwich FMLs comprising an AA2024-O metal skin and a plain-woven carbon-fiber fabric core is investigated. Three types of two-level feature interfaces are designed and introduced into the FMLs structure. To understand the effect of two-level features on the resin flow and dynamic wetting progress in resin transfer molding, two-phase flow Computational Fluid Dynamics numerical models coupled with porous media and level-set numerical methods are built. The feasibility of the numerical simulation in the qualitative analysis was verified by comparing the results with those of the testing porosity values from X-ray scanning. In addition, the mechanisms of pore formation and transportation are revealed. These results indicate that the deeper groove structure in the etched features plays an important role in discharging residual air and determining the transformation of pores to reduce porosity. The permeability orientations of the porous media and surface structure both have significant impacts on the flow behavior and formation of pores.

The fine structure of pygmy and giant multipole resonances in nuclei

In connection with the program of planned work on the megascience installation "Intensive Reverse Compton"(INOC) at the Scientific Center of Physics and Mathematics in Sarov, a brief overview of experimental and theoretical results in the field of pygmy- and giant resonance energies is presented. Considered: 1) pygmy-dipole resonance in 208Pb, for which the limit of experimental resolution has already been reached and separate 1 − levels have been identified, 2) the most important physical results of experiments with a resolution of (50–200) keV both for gamma strenght functions, that determine the characteristics of nuclear reactions, and for analysis of non–statistical mechanisms of formation of widths of giant resonances («doorway» states) in the framework of wavelet analysis. Some results in the field of excitation energies (1–5) MeV are also discussed.

Numerical Study on the Formation Mechanism of Plume Bulge in the Pearl River Estuary under the Influence of River Discharge

Previous studies have investigated the characteristics and influencing factors of plume bulge in the Pearl River Estuary (PRE) using observations and numerical simulations. However, the understanding of how river discharge affects plume bulge is not consistent, and the response mechanism of plume bulge to changes in river discharge has not been revealed in detail. In this study, a three-dimensional hydrodynamic Finite-Volume Coastal Ocean Model (FVCOM) is constructed, and five experiments were set to characterize the horizontal and vertical distribution of the plume bulge outside the PRE under different river discharge conditions during spring tide. The physical mechanisms of plume bulge generation and its response mechanisms to river discharge were discussed through standardized analysis and momentum diagnostic analysis. The results indicate that the plume bulge is sensitive to changes in river discharge. When the river discharge is relatively low (e.g., less than 11,720 m3/s observed in the dry season), the bulge cannot be formed. Conversely, when the river discharge is relatively high (e.g., exceeding 23,440 m3/s observed in flood season), the bulge is more significant. The plume bulge is formed by the anticyclonic flow resulting from the action of the Coriolis force on the strongly mixed river plume. The bulge remains stable under the combined effects of barotropic force, baroclinic gradient force, and Coriolis force. The reduction of river discharge weakens the mixing of freshwater and seawater, resulting in the reduction of both the volume and momentum of the river plume, and the balance between advective diffusion and Coriolis forces are altered, resulting in the plume, which is originally flushed out from the Lantau Channel, not being able to maintain the anticyclonic structure and instead floating out along the coast of the western side of the PRE, with the disappearance of the plume bulge. Due to the significant influence of plume bulges on the physical and biogeochemical interactions between estuaries and terrestrial environments, studying the physical mechanisms behind the formation of plume bulges is crucial.

Order–disorder–order mesophase transitions in self-assembled mesoporous alumina for enhanced CO2 adsorption

The addition of a hydrophobic micelle pore expander to self-assembling mesostructured hybrid materials enables access to new combinations with differently ordered mesophases and enhanced structural properties. Here we detail our investigations into the influence of 1,3,5-trimethylbenzene (TMB) on the self-assembly behaviors of an F127 Pluronic triblock copolymer with an aluminum oxide sol additive. By varying the chemical mixing sequence, the TMB-to-F127 mass ratio and the acid-to-metal molar ratio, we observe that TMB exhibits dual roles, functioning both as a hydrophobic swelling agent and as a low dielectric co-solvent. This induces a mesophase transition from an ordered p6mm lattice to a disordered state and subsequently back to the ordered p6mm phase. We propose a structure formation mechanism based on the DLVO theory to describe the thermodynamics and kinetic mobility of the hybrid micelles during the order-disorder and ensuing disorder-order mesophase transitions. The resulting ordered mesoporous alumina structures, with considerable pore sizes (up to 12 nm), high surface areas (up to 314 m2/g) and pore volumes (up to 0.74 cm3/g), organized pore geometry and variable inorganic wall thicknesses, have shown excellent CO2 adsorption capacities and are appealing for various applications, including stable high temperature catalyst supports, separation and sensing.

Mechanism of rainfall‐induced toppling in loess collapses

AbstractTo study the formation mechanism of rainfall‐induced soil erosion, collapse and landslides in the Loess Plateau based on the unsaturated soil seepage theory and the effective stress principle, the failure process of collapse with cracks under heavy and long‐term rainfall was investigated using the finite element method. The results showed that under the action of heavy rain, surface run‐off quickly gathered in cracks to form a dominant flow, resulting in a rapid increase in the water level and hydrostatic pressure in the cracks. The strength of the soil at the tip of the crack decreased rapidly under the softening effect of the water, and tensile failure occurred. The crack accelerated downward to the foot of the slope, causing the steep slope to collapse. Long‐term rainfall acts directly on the soil near the crack, resulting in faster saturation than the soil inside the slope body. When the rainfall time exceeded a certain value, the soil near the crack reached a saturated state, and the soil strength was minimized. Simultaneously, the seepage force generated when rainwater inside the collapsed body seeps from its outer edge increases the overturning moment of the collapsed body. Under the continuous action of rainfall, the cracks gradually extended to the foot of the slope, causing the collapsed body to fail. These research results provide a theoretical basis for the prevention and control of land degradation and collapse disasters on the Loess Plateau.

Exotic Tetraquarks at the HL-LHC with JETHAD: A High-Energy Viewpoint

We review the semi-inclusive hadroproduction of a neutral hidden-flavor tetraquark with light and heavy quark flavor at the HL-LHC, accompanied by another heavy hadron or a light-flavored jet. We make use of the novel TQHL1.0 determinations of leading-twist fragmentation functions to describe the formation mechanism of a tetraquark state within the next-to-leading order perturbative QCD. This framework builds on the basis of a spin physics-inspired model, taken as a proxy for the lowest-scale input of the constituent heavy-quark fragmentation channel. Then, all parton-to-tetraquark fragmentation functions are consistently obtained via the above-threshold DGLAP evolution in a variable-flavor number scheme. We provide predictions for a series of differential distributions calculated by the hands of the JETHAD method, well-adapted to NLL/NLO+ hybrid-factorization studies, where the resummation of next-to-leading energy logarithms and beyond is included in the collinear picture. We provide corroborating evidence that high-energy observables sensitive to semi-inclusive tetraquark emissions at the HL-LHC exhibit a fair stability under radiative corrections, as well as MHOU studies. Our analysis constitutes a prime contact point between QCD resummations and the exotic matter.

Identification of complex crude oil categories in ultra-deep petroleum systems based on a new fluorescence analysis method: An example from the southwestern Tabei Uplift, Tarim Basin, China

Ultra-deep crude oils have become one of the most important targets for petroleum exploration. In ultra-deep petroleum systems, differential hydrocarbon generation of various source rocks and multistage oil accumulation and secondary alteration processes led to the coexistence of crude oils with diverse sources and formation mechanisms. How to effectively identify complicated crude oil categories is a difficult issue confronted with ultra-deep petroleum exploration. Because crude oils are generally fluorescent, fluorescence analysis methods exhibit great application potential for classifying ultra-deep crude oils. However, due to the lack of other restrictive parameters, previous methods based on fluorescence color and fluorescence spectra limit the geological application of fluorescence analysis methods in ultra-deep petroleum systems. Based on the combination of fluorescence spectral parameters and fluorescence lifetimes, this study innovatively provides a new fluorescence analysis method for identifying complex crude oil categories in ultra-deep petroleum systems. Moreover, the sources and formation mechanisms of the ultra-deep crude oil can be further identified by combining fluorescence parameters with physical and geochemical parameters. By applying the above method, this study effectively identified three categories of crude oils and revealed their sources and formation mechanisms in the ultra-deep petroleum system of the southwestern Tabei Uplift, Tarim Basin, China. The new fluorescence analysis method may have practical significance for revealing the sources and formation mechanisms of ultra-deep crude oils.