Typical Hysteresis Research Articles

ANALYTICAL CALCULATION OF FIXED POINT OF OPERATOR GENERATED BY MULTIDIMENSIONAL SYSTEM WITH RELAY HYSTERESIS

We consider a multidimensional system of ordinary differential equations with relay nonlinearity of a hysteresis type in a special form that has made it possible to analytically calculate the fixed point of the operator generated by this system. We propose procedures for selecting a vector defining the location of discontinuity surface (switch surfaces) in the phase space such that there exists a unique fixed point on one of these surfaces. Examples representing the obtained theoretical results are given.

STUDY OF PARAMETER SPACE OF MULTIDIMENSIONAL SYSTEM WITH RELAY HYSTERESIS AND PERTURBATION

The object of research is an 𝑛-dimensional system of ordinary differential equations that contains a constant diagonal matrix with real eigenvalues, two-position relay nonlinearity of hysteresis type with a parameter and a continuous periodic perturbation function with a parameter. In the case of a special type of feedback vector (one non-zero element), we obtain conditions for system parameters that ensure the existence of a unique two-point oscillatory periodic solution with a period multiple of the perturbation function period. We establish a functional dependence of the nonlinearity parameter on the perturbation function parameter. Influence of perturbation function parameter values on the existence of the solution is investigated. We offer an algorithm for seeking system parameters and the instant of the first relay switching in the case when the solution period is given. Theoretical results, including the proposed algorithm, are illustrated by the example of a three-dimensional system.

Extremely multi-stable grid-scroll memristive chaotic system with omni-directional extended attractors and application of weak signal detection

The extreme multi-stability and omni-directional expansion of the attractors in chaotic systems play an indispensable role in the chaos-based engineering applications. In this study, a novel extremely multi-stable grid-scroll memristive chaotic system with omni-directional extended attractors is proposed, and applies it to weak signal detection. Firstly, a flux-controlled non-volatile memristor with a typical 8-shaped pinched hysteresis loop, and three piecewise linear functions that can promote the position offset of the attractor are designed. On this basis, we construct a novel grid-scroll memristive chaotic system with infinite equilibrium points, which can generate n × n × n-scroll attractors. The piecewise linear functions lead to the infinite expansion of the chaotic attractor in the x, y, and z directions, which also indirectly causes the position offset in the w direction. This phenomenon has not been discovered in existing researches. The numerical analysis demonstrates that the memristive chaotic system has infinite coexisting attractors, and a built-in parameter that can achieve global amplitude control of the attractor has also been verified. The omni-directional expansion, coexistence and global amplitude control of the attractor illustrates the extreme multi-stability of the designed system. The analog circuit of the memristive chaotic system has been implemented to verify its feasibility and practicability. Finally, a weak signal detection system based on the grid-scroll memristive chaotic system is constructed. This system not only has excellent robustness to various noise, but also is more sensitive to weak periodic signals. The detection signal-to-noise ratio (SNR) threshold reaches -63 dB. The applicability of this method in practical engineering is verified through the detection of ship radiation signals submerged in ocean background noise.

Experimental study of friction damping connections for prefabricated self-centering rocking structural elements

Self-centering rocking structural systems provide solutions for prefabricated buildings to achieve better seismic resilience. A well-designed connection of the self-centering rocking structural elements is critical to provide stable supplemental damping to the system. In this study, an innovative friction damping connection was proposed that could better match the gap-opening-closing motion of the rocking elements. Firstly, prototype experiments were carried out to investigate the connection’s mechanical behavior. The brake pad-stainless steel interface exhibited smooth sliding without chatter, stick-slip, or damage. The average static and kinetic friction coefficients were 0.30 and 0.28, respectively, showing negligible dependence on surface pressure, amplitude, or frequency. Then, the proposed connections were applied to the prefabricated shear wall-rocking coupling beam subassembly. Quasi-static cyclic loading tests on 5 full-scale specimens of the subassembly showed typical flag-shaped hysteresis curves, and the connections performed well as expected. Moreover, the theoretical analysis accurately reflected the hysteretic behavior of the specimen. Adjusting the connection’s frictional force changed the initial damping moment ratio (IDMR) of the coupling beam, determining the rocking system’s energy dissipation and self-centering capability. A reasonable IDMR value ranged from 0.8 to 0.9.

Experimental and numerical validation of center-rotation type self-centering link beam with SMA bars

This paper innovatively proposed a center-rotation type self-centering steel angle energy-consuming link beam. The influences of the SMA connection types and steel angle materials on the self-centering and energy dissipation capabilities of link beams were studied. The structural self-centering performance, energy dissipation capacity, bearing capacity, ductility, failure mode and stress distribution were analyzed through experiments. The finite element method was used to verify the test and the improved design specimens were proposed. The research results show that the self-centering link beam has a better rotation mode, and the plastic deformation is mainly concentrated on the energy-dissipating steel angles, showing excellent energy-dissipation capability. The full-length arrangement of SMA can improve the self-centering performance of the link beam and has little impact on the energy dissipation capacity. Q235 steel angle can greatly increase the energy dissipation capacity of link beams and affect the self-centering performance. The finite element results are consistent with the tests. The improved design specimens have typical double-flag hysteresis curves, which have better self-centering performance, but the energy dissipation capacity is reduced. The link beams did not undergo plastic deformation after the earthquake, and the structural function can be quickly restored by replacing the steel angles.

Enhanced energy storage performance of lead-free Sr0.7Bi0.2TiO3 ceramics via tape casting

Abstract The development of pulsed power technology demands high energy storage density dielectric materials. In this study, Sr0.7Bi0.2TiO3 relaxor ferroelectric (rFE) ceramic thick films were prepared using a tape-casting process. The ceramics exhibit a dense structure and typical rFE hysteresis curves, achieving an energy storage density of 4.77 J cm−3 and efficiency of 94.4%, attributed to the high polarization intensity, low remnant polarization, and low hysteresis loss of rFE. Additionally, the material demonstrates good temperature stability. Moreover, the Sr0.7Bi0.2TiO3 ceramic thick films show advantages in charge-discharge performance, capable of discharging within hundreds of nanoseconds and achieving a power density of 137 MW cm−3. Overall, the Sr0.7Bi0.2TiO3 ceramic thick film exhibits a comprehensive performance advantage in terms of energy storage density, efficiency, and power density. Additionally, the material was fabricated using the tape-casting process, which is compatible with subsequent multilayer ceramic capacitor production, indicating potential for further performance enhancement.

Magnetic Field-Induced Polar Order in Monolayer Molybdenum Disulfide Transistors.

In semiconducting monolayer transition metal dichalcogenides (ML-TMDs), broken inversion symmetry and strong spin-orbit coupling result in spin-valley lock-in effects so that the valley degeneracy may be lifted by external magnetic fields, potentially leading to real-space structural transformation. Here, magnetic field (B)-induced giant electric hysteretic responses to back-gate voltages are reported in ML-MoS2 field-effect transistors (FETs) on SiO2/Si at temperatures <20 K. The observed hysteresis increases with |B| up to 12 T and is tunable by varying the temperature. Raman spectroscopic and scanning tunneling microscopic studies reveal significant lattice expansion with increasing |B| at 4.2 K, and this lattice expansion becomes asymmetric in ML-MoS2 FETs on rigid SiO2/Si substrates, leading to out-of-plane mirror symmetry breaking and the emergence of a tunable out-of-plane ferroelectric-like polar order. This broken symmetry-induced polarization in ML-MoS2 shows typical ferroelectric butterfly hysteresis in piezo-response force microscopy, adding ML-MoS2 to the single-layer material family that exhibits out-of-plane polar order-induced ferroelectricity, which is promising for such technological applications as cryo-temperature ultracompact non-volatile memories, memtransistors, and ultrasensitive magnetic field sensors. Moreover, the polar effect induced by asymmetric lattice expansion may be further generalized to other ML-TMDs and achieved by nanoscale strain engineering of the substrate without magnetic fields.

Comparison on Hysteresis Loops and Dislocation Configurations in Fatigued Face-Centered Cubic Single Crystals

The aggregation and evolution of dislocations form different configurations, which are the preferred locations for fatigue crack initiation. To analyze the spatial distribution of the same dislocation configuration and the resulting configuration morphologies on different observation planes, several typical hysteresis loops and dislocation configurations in fatigued face-centered cubic single crystals with various orientations were compared. The crystal orientations of these specimens were determined by the electron back-scattering diffraction technique in a Cambridge S360 Scanning Electron Microscope. It is well known that dislocation ladder and wall structures, as well as patch and vein structures, are distributed on their respective observation planes, (12¯1) and (111). These correspond to the point defect direction and line defect direction of dislocations, respectively. Therefore, the wall structures on the (12¯1) and (111) planes consist of point defects and line defects, which can be defined as point walls and line walls, respectively. Furthermore, the walls on the (12¯1) plane consist of Persistent Slip Band ladders connected with each other, corresponding to the formation of deformation bands. The evolution of dislocation patterns follows a process from patch to ladder and from vein to wall. The formation of labyrinths and dislocation cells originates from the activation of different secondary slip systems. In one word, it can help us better understand the physical nature of metal fatigue and failure by studying the distribution and evolution of different configurations.

Component design for stabilizing P phase in NaNbO3-based ceramics and the energy storage performance

Antiferroelectric (AFE) ceramic dielectrics are widely recognized for their high potential in high-power pulse equipment applications. Lead-free NaNbO3 (NN) antiferroelectric ceramics have emerged as a prominent research topic in the field of energy storage due to their abundant phase structure, affordability, and moderate bandgap. The metastable ferroelectric Q phase results in a square hysteresis loop for NN at room temperature. However, 0.96NaNbO3-0.04 CaZrO3 (NNCZ) exhibits a typical double hysteresis loop at room temperature with the main crystalline phase being the antiferroelectric P phase, which has poor energy storage performance. In this study, Bi0.5Na0.5TiO3 (BNT) is used to optimize the energy storage performance and stabilize the P phase in NNCZ simultaneously. The dielectric constant and temperature-dependence XRD results that from −100 °C to 350 °C, x = 0.05 undergoes a phase transition from AFE P to AFE R and then to PE S. The solid solution of BNT decreased the sintering temperature of NN-based ceramics and decreased average grain size, thereby facilitating domain size reduction and improving the sample's energy storage efficiency from ∼30 % to ∼60 %, with an effective energy storage density reaching 1.51 J/cm3. The above results demonstrate that enhancing energy storage efficiency can be achieved through component design by reducing average grain size.

Influence of XeCl excimer laser annealing on the ferroelectric nondoped HfO2 formation deposited on a Si(100) substrate

In this research, we have investigated the effect of excimer laser annealing (ELA) on the ferroelectric nondoped HfO2 (FeND-HfO2) formation deposited on a Si(100) substrate. The XeCl (λ: 308 nm) ELA was irradiated as post-deposition annealing (PDA) in the N2 ambient to the 10 nm thick HfO2 deposited by RF-magnetron sputtering without substrate heating. The C–V characteristics of Al/HfO2/p-Si(100) metal/ferroelectrics/Si (MFS) diodes were gradually improved with the energy density of ELS from 170 mJ cm−2 to 270 mJ cm−2 irradiated at 200 Hz for 200 shots although the charge-injection type hysteresis of 0.2–0.3 V remained. The post-metallization annealing (PMA) at 400 °C/5 min in N2/4.9%H2 ambient for Al/HfO2/p-Si(100) MFS diodes markedly improved the C–V characteristics, and negligible hysteresis with ideal flat-band voltage (V FB) was realized. The memory window (MW) of 0.42 V was achieved by the program/erase (P/E) operation with the input pulses of +3 V/100 ms and −8 V/100 ms for the MFS diode with an ELA energy density of 270 mJ cm−2 at 200 Hz for 200 shots followed by the PMA.

Modulated magnetostriction and multiferroic properties in the PVDF-based cobalt ferrite particulate composites

Multiferroic materials (MFM) have drawn substantial attention for developing smart magnetodielectric devices. Herein, cobalt ferrite CoFe2O4 (CFO) was synthesized by a glycine–nitrate sol-gel auto-combustion route and, PVDF-based particulate composite films embedded with CFO have been developed. A comprehensive investigation evaluated the effects of magnetostriction, initiated from the embedded CFO phase, on magnetodielectric characteristics of composite films. The structural, electrical, magnetostrictive and magnetodielectric properties were investigated. The embedded CFO particulate endows PVDF matrix at a higher β–phase forming ability, which enhances the ferroelectricity with a polarisation (Pmax∼1.09 μC/cm2@ 850 kV/cm), a higher dielectric constant (εr∼12.33) and lower dielectric loss. The typical magnetic hysteresis loop was obtained with saturation magnetization (MS∼4.96 emu/g) and coercivity (HC∼1.49 kOe), revealing the ferromagnetic ordering in composite films. The response of the magnetodielectric (MD) is observed at room temperature, that is, a large negative MD coefficient ∼2.1 % @ Hcr∼5.0 kOe is achieved for Co0.9Fe2.1O4/PVDF composite films, while MD∼0.65 %@ Hcr∼1.0 kOe is obtained for Co1.1Fe1.9O4/PVDF films, accompanied by a maximum MD∼4.35 % at resonance frequency. The variation in the MD performance reveals a close correlation to the modulated magnetostriction, such as the magnetocrystalline anisotropy, field-induced coefficient and magnetostrictive susceptibility, indicating the strain-mediated coupling MD effect. The multiferroic properties in CoxFe3–xO4/PVDF composites have potential for magneto-dielectric sensing applications. Furthermore, this work would be exploited to understand MD coupling mechanism and develop MFM for multifunctional devices.

Silver nanoparticles from ascorbic acid: Biosynthesis, characterization, in vitro safety profile, antimicrobial activity and phytotoxicity

Skin lesions are caused by the interruption of their functions, causing several possibilities of injury, and affecting the patient's quality of life. Thus, an effective alternative to this problem is the application of metallic nanoparticles with considerable antimicrobial activity, such as silver nanoparticles (AgNPs). In this context, the present study aims to synthesize and characterize AgNPs from l-ascorbic acid (AA) for a possible cutaneous tissue engineering, evaluating the in vitro safety profile (VERO cells line), antimicrobial activity (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa strains), genotoxicity effect and phytotoxicity (Lactuca sativa and Beta vulgaris L. seeds). The novelty of the present study consists of applying green silver nanoparticles for potential application in skin lesions, followed by the study of toxicity in seeds (phytotoxicity), cells (cytotoxicity and genotoxicity with the in vitro safety profile), and antimicrobial activity. X-ray diffraction (XRD), N2 porosimetry, Field Emission Gun – Scanning Electron Microscope (FEG-SEM), zeta potential (ZP), Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and Fourier-transform infrared spectroscopy (FT-IR) were used to evaluate the morphological, structural, and textural properties of the AgNPs. XRD diffractogram showed characteristic peaks of a face-centered cubic crystal structure at 38.06° (111); 44.26° (200); 64.45° (220); 77.37° (311) and 81.34° (200). FEG-SEM micrography indicated a predominantly spherical morphology and uniformly distributed structure with an average size of 58.4 ± 19 nm. Moreover, AgNPs demonstrated functional groups characteristics of the reducing agent and the metallic precursor, such as the –OH, –CH, –CO, - CC, and Ag–O stretchings. AgNPs showed SBET = 0.3 ± 0.0085 m2 g−1, Dp = 16.2 ± 10.2 nm, Vp = 0.0008 ± 0.0002 cm³ g−1 and ZP = −27.6 ± 1.9 mV with hysteresis type H1 and mesoporous characteristics. EDX analysis indicated the presence of AgNPs (72.34 wt% and 10.46 wt% silver and oxygen respectively) indicating the effectiveness of the biosynthesis process. For the in vitro safety profile, AgNPs did not show cytotoxicity on VERO cells ranging from 0.5 to 150 μg mL−1 with a good gemoprotection. The minimum inhibitory concentration (MIC) showed that AgNPs have an inhibition of 312 μg mL−1 and 156 μg mL−1 on Gram-positive and Gram-negative strains, respectively. The phytotoxicity showed that only high concentrations (50 and 100 μg mL−1) of AgNPs interfered with seed growth. Therefore, AgNPs biosynthesized from l-ascorbic acid (AA) have potential applications as antimicrobial dressings and are biocompatible for application in skin lesions.

Identification of Hammerstein models with hysteresis nonlinearity

This paper deals with the identification of Hammerstein nonlinear models. The system nonlinearity is not necessarily static and can be of hysteresis type. The latter nonlinearity can be backlash, switch or any other memory operator having several transient cycles, but one permanent (major) cycle. The LTI (Linear Time-Invariant) block is nonparametric and is described by its impulse response. The considered system’s nonlinearity is any memory operator having one major cycle (periodic closed loop), which is bordered by any two arbitrary functions. The nonlinearity borders are not assumed to be invertible. The proposed identification algorithm can be used in static nonlinearity, e.g. polynomial nonlinearity, dead zone function or any piecewise affine functions. Unlike several previous studies, the proposed identification method is carried out using only one stage. In this approach, an input signal of piecewise constant (staircase) is used. It is shown that the estimated parameters converge to their true values.

Capacitive and Inductive Characteristics of Volatile Perovskite Resistive Switching Devices with Analog Memory.

With the increasing demands and complexity of the neuromorphic computing schemes utilizing highly efficient analog resistive switching devices, understanding the apparent capacitive and inductive effects in device operation is of paramount importance. Here, we present a systematic array of characterization methods that unravel two distinct voltage-dependent regimes demonstrating the complex interplay between the dynamic capacitive and inductive effects in volatile perovskite-based memristors: (1) a low voltage capacitance-dominant and (2) an inductance-dominant regime evidenced by the highly correlated hysteresis type with nonzero crossing, the impedance responses, and the transient current characteristics. These dynamic capacitance- and inductance-dominant regimes provide fundamental insight into the resistive switching of memristors governing the synaptic depression and potentiation functions, respectively. More importantly, the pulse width-dependent and long-term transient current measurements further demonstrate a dynamic transition from a fast capacitive to a slow inductive response, allowing for the tailored stimulus programming of memristor devices to mimic synaptic functionality.

VO2 thin films: various microstructures for hysteresis manipulations

Vanadium dioxide reveals a phase change transition at 68 °C associated to typical hysteresis curves with strong variations in physico-chemical properties. The study presented here aims to investigate the influence of the structure and the microstructure of VO2 condensed matter on optical transmittance and electrical resistivity hysteresis curves during the metal-insulator transition. The characteristics of VO2 thin films synthesized through conventional laser ablation and of VO2 nanoparticle stacks generated via a laser vaporization cluster source are investigated. This study reveals the capability to modulate the transition temperature by as much as 20 °C, the transition width within the range of 4–30 °C, and the resistivity dynamics across the semiconducting-to-metallic phase transition by more than two orders of magnitude. These effects appear to arise because of the change of microstructure, the physical percolation of nanoparticles and associated collective effects.More complex hysteresis behaviors, taking benefit of the fabrication processes presented in this paper, and coupling the two previous distinct VO2 architectures (thin film and nanoparticles stack) lead to optical transmittance curves with three transition levels. This approach offers flexibility beyond binary responses, facilitating the design of innovative optoelectronic devices with n-stages modulation capabilities. Near room temperature applications of VO2 metal-insulator transition are underscored, highlighting opportunities for tailored architectures to exploit its properties effectively.

Simultaneous removal of fluoride and nitrate from an aqueous mixture and semiconductor wastewater by sodium chloride mediated electro-generated aluminas (EGAs): Conversion of recovered fluoride into fluorapatite using plasterboard waste

Electro-generated aluminas (EGAs) were synthesized using sodium chloride electrolyte of 100 mM with Al/Al and Al/Fe electrodes operated at 800 mA for 1.5 h. The synthesized mesoporous EGAs, EGA (Al) and EGA (Fe) belonging to H2 type hysteresis contain the boehmite and bayerite phases as confirmed by XRD analysis and whose proportions are estimated to be 49.6 ± 0.3% and 50.4 ± 0.3% respectively by thermo-gravimetric study. The batch adsorption studies were conducted using the binary (F−/NO3−) mixture from which the adsorption efficiency was studied as a function of time (0–60 min), pH (3–10), initial concentration of fluoride or nitrate (100, 300, 500 and 1000 mgL−1) and temperature (15 °C, 25 °C, 35 °C and 45 °C) using EGA (Al) and EGA (Fe) adsorbents. The adsorptive removal of fluoride and nitrate from real effluent samples using EGAs was significant particularly in effluents E1 and E3 with residual concentrations within the safe limit of World Health Organization (WHO). Regeneration using 100 mM NaOH was quite consistent up to five consecutive cycles and the recovered fluoride was converted into fluorapatite. Taking into account the regeneration aspect, the cost analysis showed that 1 g EGA (Al) and EGA (Fe) was 0.464 USD and 0.508 USD respectively. The endothermic nature of adsorption through chemical forces was confirmed by the compliance of pseudo – second – order (kinetic), Langmuir and DKR (isotherm) models (R2 ≈ 0.99) along with thermodynamic parameters. Characterization of EGAs using FTIR, FESEM, XRD, XPS and BET was done to understand the adsorptive behavior between EGAs and the adsorbate (F−/NO3−) ions. The exhausted EGAs after fifth cycle of regeneration was mixed with ariake clay, plasterboard waste and cement in proper proportions and, made as specimens for the construction of bank bodies.

A Novel Dual-Mode Dual Type Hysteresis Schmitt Trigger and its Applications using Single Differential Voltage Current Conveyor Transconductance Amplifier

A Novel Dual-Mode Dual Type Hysteresis Schmitt Trigger and its Applications using Single Differential Voltage Current Conveyor Transconductance Amplifier

Sorption Hysteresis: A Statistical Thermodynamic Fluctuation Theory.

Hysteresis is observed commonly in sorption isotherms of porous materials. Still, there has so far been no unified approach that can both model hysteresis and assess its underlying energetics. Standard approaches, such as capillary condensation and isotherms based on interfacial equations of state, have not proved to be up to the task. Here, we show that a statistical thermodynamic approach can achieve the following needs simultaneously: (i) showing why adsorption and desorption transitions may be sharp yet continuous; (ii) providing a simple (analytic) isotherm equation for hysteresis branches; (iii) clarifying the energetics underlying sorption hysteresis; and (iv) providing macroscopic and nanoscopic perspectives to understanding hysteresis. This approach identifies the two pairs of parameters (determinable by fitting experimental data) that are required to describe the hysteresis: the free energy per molecule within the pore clusters and the cluster size in the pores. The present paper focuses on providing mechanistic insights to IUPAC hysteresis types H1, H2(a), and H2(b) and can also be applied to the isotherm types IV and V.

PERFORMANCE COMPARISON OF DERIVATIVE-FREE OPTIMIZATION METHODS

Structural optimization for parameters and non-parameters-based modelling are adopted in almost all area of science and engineering due to their inherent advantages in contrary to manual tuning. Typically, in the easiest case regression analysis is used to develop a data-based model for the future applications and forecasting. However, the aforementioned modelling approach may be suitable for well-defined data (i.e., elastic model) but might be difficult for complex data type where linear type model may show very poor performances. As a result, the adaptation of nonlinear type or complex models (e.g. a combination of linear and nonlinear parts) are unavoidable. For instance, modeling of a hysteresis type behavior would not be possible via any linear type models while a Bouc-Wen type nonlinear model would be a better choice. Hence, to avoid early mentioned issues and to achieve better performances, the derivative-free or search-algorithm optimization might be suitable alternatives. Herein, due to the underlying advantages, the derivative-free search algorithms have been adopted to optimize model performances and interpret both linear and nonlinear type data. To be precise, two different derivative-free algorithms namely, (i) Nelder-Mead Simplex Method, and (ii) Genetic Algorithm have been studied. The outcome of this study shows that in both former mentioned cases search-based algorithms have better performance in terms of capturing the behavior of the true data via optimization. The real-life applications of optimization algorithms are numerous as these tools are used in many branches of science and engineering.

Using Fractal Theory to Study the Influence of Movable Oil on the Pore Structure of Different Types of Shale: A Case Study of the Fengcheng Formation Shale in Well X of Mahu Sag, Junggar Basin, China

This study investigated the influence of movable oil on the pore structure of various shale types, analyzing 19 shale samples from Well X in the Mahu Sag of the Junggar Basin. Initially, X-ray diffraction (XRD) analysis classified the shale samples. Subsequently, the geochemical properties and pore structures of the samples, both pre and post oil Soxhlet extraction, were comparatively analyzed through Total Organic Carbon (TOC) content measurement, Rock-Eval pyrolysis, and nitrogen adsorption experiments. Additionally, fractal theory quantitatively described the impact of movable oil on the pore structure of different shale types. Results indicated higher movable oil content in siliceous shale compared to calcareous shale. Oil extraction led to a significant increase in specific surface area and pore volume in all samples, particularly in siliceous shale. Calcareous shale predominantly displays H2–H3 type hysteresis loops, indicating a uniform pore structure with ink-bottle-shaped pores. Conversely, siliceous shale exhibited diverse hysteresis loops, reflecting its complex pore structure. The fractal dimension in calcareous shale correlated primarily with pore structure, exhibiting no significant correlation with TOC content before or after oil extraction. Conversely, the fractal dimension changes in siliceous shale samples do not have a clear correlation with either TOC content or pore structure, suggesting variations may result from both TOC and pore structure.