Structural Evolution Characteristics Research Articles

Genetic Types of the tp12cx Strike-Slip Fault Segments and Their Role in Controlling Reservoirs in the Tarim Basin

The change of motion mode of multistage active strike-slip faults controls the segmentary types of strike-slip faults, which is seldom studied.Based on high-precision 3D seismic data and the principle of structural analysis, this paper defines the structural evolution characteristics of the tp12cx strike-slip fault in the key structural period and identifies the fault segmentation types. Combined with the statistical results of drilling production data and fault width, and fault width, it is demonstrated that different fault segments display various reservoir architecture and hydrocarbon potential. The tp12cx strike-slip fault experienced two phases of tectonic activity controlling reservoir development: the middle Caledonian and the late Caledonian to early Hercynian. During the middle Caledonian period, a left-lateral and left-step strike-slip fault was formed. The overlapping segments of the left steps were transtension zones, and the rest were pure strike-slip segments. From the late Caledonian to the early Hercynian, the movement mode changed from left-lateral to right-lateral, and the arrangement of left steps remained unchanged, forming right-lateral and left-step strike-slip faults. That is, as a weak zone, the transtension zones of all the preexisting overlapping segments took the lead in moving into many pure strike-slip segments and maintained the transtensional property. During the right-lateral slipping process of all the original pure strike-slip segments along the fault, they were blocked and squeezed by the surrounding rocks on both sides, forming a series of “positive” flower-shaped fault anticlines, which became overlapping segments, and the fault property became transpressional. Under the continuous action of the right-lateral slipping, a regional right-lateral and right-step strike slip fault formed. The interiors of the right-step-arranged faults were composed of the left-step arranged faults. Among them, the right-step overlapping segments were weakly step overlapping segments were weakly transtensional, and the larger the fault width of the internal left step pure strike slip and overlapping segments, the stronger the dissolution. The deformation of the right-step pure strike-slip segments was weak and basically maintained the characteristics of the previous stage. According to the evolution and superposition of pure strike-slipped and overlapped segments and the changes in fault properties, four types of strike-slip fault segments and corresponding reservoir models are divided. Type I: left-step pure strike-slip segment + left-step transpressional segment + right-step transtensional segment; Type II: left-step transtensional segment + left-step pure strike-slip segment + right-step transtensional segment; Type III: left-step pure strike-slip segment + left-step transpressional segment; and Type IV: left-step transtensional segment + left-step pure strike-slip segment. The fault width and oil production of type II and type IV with transtensional properties are much larger than those of type I and type III with transpressional properties.

Spatiotemporal Evolution of Crop Planting Structure in the Black Soil Region of Northeast China: A Case Study in Hailun County

Detailed characteristics of crop planting structure (CPS) evolution can inform the optimization of the crop yield proportion in the black soil region of Northeast China (BSRNC). Choosing Hailun County as an example, this study sought to analyze the geographic characteristics of CPS evolution from 2000 to 2020. Our analysis produced new spatiotemporal information based on the remote-sensing interpretation data, namely, Landsat4-5 TM, Landsat7 ETM+, and Landsat8 OLI images. The study characterized the temporal and spatial dynamics of CPS. Our results showed the following: (1) Soybean and maize were the main crops, with a total land area of 70%; they alternated as the most dominant crop. (2) The distribution breadth and aggregation intensity of soybean and maize were spatially complementary; rice had the smallest distribution range but strong water aggregation. (3) The evolution pattern of CPS was the interconversion between a single type of soybean and maize. Our results indicate that the future CPS adjustment of BSRNC needs to consider the county-level optimization of crop area proportion and crop spatial distribution. This context has excellent implications in geographically informing policymaking to adjust county-level CPS of BSRNC, thus safeguarding food security.

Investigation on the evolution characteristics of bed porous structure during iron ore sintering

To better understand the evolution characteristics of bed porous structure during iron ore sintering, X-ray computed tomography scanning technology was used to analyze the pore parameters in different areas of the sintering bed. A pore skeleton structure model was established to study the characteristics of the airflow channels in different zones. The absolute permeability of different areas was calculated through simulation, and the corresponding streamline and pressure drop distribution were analyzed. The results show that the porosity of raw material zone, high-temperature zone, and sintered zone increases gradually, which are 37.69%, 46.41%, and 55.57%, respectively. The absolute permeability calculation results of the raw material zone and sintered zones are 792.49 μm2 and 20560.80 μm2, while the tortuosity is 1.77 and 1.45, respectively. Compared with the raw material zone, the flow streamline in the sintered zone is thicker and denser, the airflow resistance and the pressure drop are minor.

Origin of large piezoelectricity in BF-BT based multiphase ferroelectrics

Bismuth ferrite-barium titanate (BF-BT) based ferroelectrics with multi-phase coexistence exhibit promising piezoelectricity, while whose physical mechanism of property enhancement is poorly understood. In the present work, the Rayleigh law, in-situ electric field dependent synchrotron X-ray diffraction and ex-situ piezo-response force microscopy were utilized to gain insight into the property and structure evolution characteristics under electric fields. Extrinsic contribution from domain wall motion was regarded as the major determiner in piezoelectricity of the 0.69Bi1.05Fe0.99Sc0.01O3-0.3BaTiO3-0.01Bi1.05(Zn0.5Hf0.5)O3 ferroelectrics with rhombohedral and pseudo-cubic phase coexistence, different from those proposed structural origins in BF-BT based relaxor ferroelectrics (with high BT content) with large strain response. By analyzing the property discrepancy between unpoled and poled samples, the enhanced polarization and electro-strain in poled ceramics were attributed to the activated domain state induced by the direct current pre-poling.

Fatigue Test on Heavy Haul Railway Tunnel Bottom Structure With Base Cavity

The presence of a base cavity will degrade the bearing capacity of tunnel bottom structures, and will also have a noteworthy impact on its fatigue performance. In order to study the fatigue performance and cumulative damage to tunnel bottom structure, a series of bending fatigue tests are conducted by reference to a heavy haul railway tunnel with a base cavity. Through the tests, fatigue evolution characteristics of tunnel bottom structure with cavity are obtained, then based on the expression of S-N curves, a non-linear fatigue cumulative damage model is therefore proposed, the deflection evolution and cumulative damage evolution can be divided into three stages, and characterized with an “s-shaped” curve. The tests results reveal that the damage to the tunnel bottom structure develops rapidly when a cavity exists in the base rock, fatigue occurs more easily, and the fatigue life of specimens decreases with the increase of the stress level and cavity width.

Sequential surface passivation for enhanced stability of vapor-deposited methylammonium lead iodide thin films

Understanding the correlation between surface passivation and degradation kinetics in vapor-deposited organic–inorganic hybrid perovskite thin films is crucial for developing strategies to enhance their structural integrity for long-term operational stability. Here, we demonstrate that the sequential introduction of vapor-phase phenethylammonium iodide (PEAI) and methylammonium (MAI) into methylammonium lead iodide (MAPbI3) thin films, which is obtained from PbI2, suppresses their degradation and enhances the ambient stability. Compared with the simultaneous PEAI introduction during the conversion of PbI2 to MAPbI3, the MAPbI3 films with sequential treatment exhibited higher PEAI surface coverage, which imparts superior resistance to degradation. Combined analyses of the exposure-time-dependent crystal structure evolution, photoemission profiles, and photocurrent generation characteristics of the films reveal that conformal PEAI passivation suppresses the volatile release of methylammonium (MA) species and the inclusion of O2/H2O molecules. This study highlights the importance of developing a vapor-phase passivation strategy for innate polycrystalline perovskite thin films and their optoelectronic applications with long-term stability.

Release characteristics of AAEMs and physicochemical structural evolution of char during rapid coal pyrolysis

Rapid pyrolysis experiment of Zhundong coal was conducted in a high-frequency furnace to investigate release characteristics of alkali and alkaline earth metals (AAEMs) and its correlation with changes of physical and chemical properties of char. Residence time and atmosphere during pyrolysis were important process parameters that affected the migration characteristics of AAEMs and physicochemical structural evolution of char. Experimental results show that the release of AAEMs in coal char increases over time. The maximum release rate of Na, Mg and Ca is 61.05%, 64.47%, and 44.01%, respectively. Promoting effect of CO2 on release of Na mainly occurs in the initial stage of rapid pyrolysis, nevertheless the promoting effect on release of Mg and Ca mainly is in the middle and late stage. CO2 accelerates release of AAEMs by promoting release of volatiles, facilitating decomposition of oxygen-containing functional groups and aliphatic functional groups, and promoting formation of cracks on surface of coal char.

Study on the stability of foamed gel and its structural evolution characteristics

ABSTRACT Foamed gel is an efficient material for coal spontaneous combustion prevention and control, which effectively combines the fire prevention and extinguishing properties of foam and gel. In this paper, the formation principle, structural evolution, stability, and fluidity of foamed gel are elaborated. Foamed gel is mainly formed by foaming agent, cross-linking agent and water through physical foaming and gelling reaction, and its formation process is divided into two stages: the first stage is physical foaming and forming foam; the second stage is adding cross-linking agent to foam and generating foamed gel through gelling reaction. The first stage of foamed gel mainly reflects the fluidity and stacking of foam, and in the second stage, with the increase of gel amount, foamed gel reflects the temperature resistance of gel. The basic structure of the foamed gel is the same as that of the water-based foam, and the gel particles constitute the basic skeleton of the foamed gel, which slows down the gravitational drainage and foam disproportionation rate. The evolution process of foamed gel structure includes liquid film rupture, gel formation and skeleton collapse, which eventually forms a gel layer to fill the residual coal fissure. The flow of foamed gel in the mining area is subject to the combined effect of grouting pressure, gravity and resistance, and the lateral flow velocity is larger than the longitudinal flow velocity, and the contour line of its diffusion front peak is ellipsoidal.

Evolution of Microstructure during Rapid Solidification of SiC under High Pressure

The microstructure evolution of liquid silicon carbide (SiC) during rapid solidification under different pressure values is simulated with the Tersoff potential using molecular dynamics. The structure evolution characteristics of SiC are analyzed by considering the pair distribution function, bond angle distribution, coordination number, and the diagrams of the microstructure during rapid solidification. The results show that the average energy of atoms gradually increases with pressure. When the pressure reaches 100 GPa, the average energy of the atom is greater than the average energy of the atom in the initial liquid state. Under different pressures, the diffusion of atoms tends to remain stable at a temperature of about 3700 K. The application of pressure has a major impact on the arrangement of atoms, except on the third-nearest neighbor, while the impact on the nearest neighbor and the second-nearest neighbor is relatively small. The pressure increases the medium-range order of the system. The coordination numbers of Si and C atoms gradually decrease with the decrease in temperature and increase in pressure. Pressure changes the microstructure of the SiC amorphous system after solidification, and the density can be increased by adjusting the coordination number of atoms. As the pressure increases, the SiC amorphous system exhibits a dense structure with coordination numbers of 4, 5, 6, and 7.

Structural Evolution and Motion Characteristics of a Hard Roof During Thickening Coal Seam Mining

This study combined theoretical analysis, physical simulation, and numerical simulation to discuss the influences of the structural evolution and motion characteristics of a hard roof during thickening coal seam mining on working face pressure. Results showed that during the mining of the thickening coal seam with a hard roof, the settlement curve of low-level strata was a stepwise wave slope, and the settlement curve of high-level strata shifted from a “V-shaped” distribution pattern to a parabola under the full mining of the coal seam. When the mining thickness was relatively small, the mining space expanded with the increase in mining thickness due to the “masonry beam” structure formed by the low-level, sub-critical overlying strata. The low-level critical strata formed a “composite cantilever beam” structure with a hard immediate roof after advancing into the caving zone. After complete recovery, the overlying strata were in a steady-movement state, and the plastic failure zone of the overlying strata of the thickening coal seam presented obvious distribution characteristics of longitudinal and transverse partitions. This study provides theoretical reference for coal seam mining under similar geological conditions.

Pore Structure Evolution and Seepage Characteristics in Unclassified Tailing Thickening Process

The tailing paste thickening technology was investigated to achieve goaf reduction treatment and tailing resource utilization of metal mines and reach the effect of controlling two hazards with one waste. However, superfine tailing particles could easily form suspended water-locking flocs in the thickening process, which seriously affected the increase in the underflow concentration in the thickener. Undisturbed compression-stage bed samples were extracted using an in situ sampling method through a continuous dynamic thickening experiment. Then, the morphologies and geometrical structures of micropores were analyzed through high-precision computed tomography scanning. Subsequently, the influences of the shear evolution of pore structure and seepage channel on the dewaterability of underflow slurry were explored by combining Avizo software and 3D reconstruction technology. The thickening and dewatering mechanism of underflow slurry was also revealed. Results showed that under the shear action, the flocs were deformed and compacted, forming a high-concentration underflow. On this basis, the original micropores were extruded, deformed and segmented. Moreover, many loose micropores were formed, the connectivity became poor and the total porosity declined. The diameter of the water-conducting channel in the sample was enlarged because of the shear force and the seepage effect improved. The maximum flow velocity inside the pores was 1.537 μm/s, which was 5.49% higher than that under the non-shear state.

Superconductivity in In2Te3 under Compression Induced by Electronic and Structural Phase Transitions.

Indium telluride (In2Te3) is a typical layered material among III-IV families that are extremely sensitive to pressure and strain. Here, we use a combination of high-pressure electric transport, Raman, XRD, and first-principles calculations to study the electronic properties and structural evolution characteristics of In2Te3 under high pressure. Our results reveal the evidence of isostructure electronic transitions. First-principle calculations demonstrate that the evolution of phonon modes is associated with the transition from semiconductor to metal due to the increase in the density of states near the Fermi level. The pressure-induced metalization as a precursor monitors the structural phase transition, and then the superconductivity is produced. Further, in decompression, Tc slightly increased and remained at 3.0 GPa, and then the disorder is present and the superconductivity is suppressed. Our work not only perfects the superconducting phase of the In-Te system under pressure but also provides a reference for further superconducting research and applications.

Experimental Study on the Effect of Large Temperature Difference on Compressive Strength and Pore Structure of Semirigid Base

Understanding the evolution of mechanical properties and pore structure of semirigid base under large temperature difference is of great significance for evaluating the durability and safety of semirigid base structure and studying the damage cracking mechanism and prevention technology of semirigid base induced by large temperature difference climate. This paper studies the variation law of peak stress and dynamic modulus, the evolution characteristics of pore structure, and the pore size distribution of semirigid base after different cycles at different temperature intervals. Based on the analysis of peak stress and dynamic modulus test results, the degradation effect of freeze‐thaw environment (−20°C∼20°C) on semirigid base is far greater than that of high‐temperature environment (20°C∼60°C) and low‐temperature environment (−5°C∼−30°C). There are significant decreases in peak stress and dynamic modulus of semirigid base in the late cycle (12 to 15 cycles). Under low‐temperature and freeze‐thaw environments, the axial load resistance of semirigid base is significantly correlated with the deformation resistance, and the correlation between the two is not significant under high‐temperature environment. The variability of the thermal expansion and contraction characteristics of the internal microscopic phases of the semirigid base and the force characteristics of the pore interface phases are the root causes of the damage and cracking of the pavement base in a large temperature difference climate.

Characteristics of Pore Structure Evolution of Spent Fcc Catalyst and its Effect Mechanism on Regeneration at Different Atmospheres

Characteristics of Pore Structure Evolution of Spent Fcc Catalyst and its Effect Mechanism on Regeneration at Different Atmospheres

Study on the upgrading of industrial structure of resource-based cities in Heilongjiang Province

China is in a crucial period of transforming its development mode, optimizing its economic structure and transforming its growth impetus. The key way to realize economic transformation and development is to upgrade the industrial structure in order to cultivate new economic growth power and change economic development mode for the resource-based cities. Based on the data of industrial structure, this paper analyzes the trend and characteristics of industrial structure evolution of resource-based cities in Heilongjiang Province, and put forward the countermeasure suggestion on the resource-based city industrial structure transformation and the advanced development.

Optimization Design of Ferry Material Performance Test System Based on Artificial Intelligence

Lead titanate in titanium‐titanium mine and lead (solid solution optimized ferroelectric) is one of the most widely used multifunctional material systems, and they are outside the field (such as light, electricity, and heat) Structure, domain, and phase evolution characteristics are important for ferroelectric, piezoelectric, photoelectric, and memory applications. Functional materials are those high‐tech materials with excellent electrical, magnetic, optical, and thermal functions, special physical, and chemical and biological effects, capable of completing functional interconversion, mainly used to manufacture various functional components and are widely used in various high‐tech fields. This paper mainly analyzes iron and electrical materials and artificial intelligence technology by studying the characteristics of ferroelectric materials and research status at home and abroad and using artificial intelligence technology and the calculation of ferroelectric materials for artificial intelligence technology and Dexie optimization model. Artificial intelligence is a new technical science that studies and develops theories, methods, technologies, and application systems for simulating, extending, and expanding human intelligence. For artificial intelligence before the optimization of the hardware and software of the ferroelectric material performance test system, the optimized system is performed; the optimized system is subjected to safety testing; all test results show that the performance test of the ferroelectric material after optimization. The system data is well operating, and the artificial intelligence technology is suitable for optimization of the performance test system of ferroelectric material.

Research on Structural Evolution and Microseismic Response Characteristics of Overlying Strata during Repeated Mining of Steeply Inclined and Extra Thick Coal Seams

Abstract Repeated mining is the main factor that leads to development, propagation, and eventual deformation of the overlying strata fissures in the steeply inclined and extra thick coal seams (SIETCS). The evolution of the overlying strata structure is closely related to microseismic events in a mine. As the mining depth increases, the evolution rules of the overlying strata structure become more complicated and can easily induce dynamic disaster accidents. To solve these problems, this paper established a physical similarity simulation model. Microseismic monitoring equipment was used to study the relationship between the evolution of the overlying strata structure and the energy-frequency of microseismic events. On the basis of the principle of quantitative seismology, the response relationship between the overlying strata structure and the microseisms at different mining stages was compared and analyzed from a quantitative perspective. The characteristics of cumulative apparent volume, energy index, and microseismic b value were used to reveal the precursor characteristics of overburden instability and failure. The results showed that due to the occurrence characteristics of coal seam, the distribution characteristics of rock stratum stress, and the effects of mining disturbances, the energy accumulation-release period after instability failure of the overlying strata induced by shallow mining was longer than the energy accumulation-release period induced by deep mining. And the deep coal and rock mass had a periodic “balance-instability-rebalance-instability again” dynamic evolution process under the disturbance of repeated mining. In the working face mining, the slope of the accumulative apparent volume ΣVA curve suddenly increased, and the energy index EI gradually decreased at the late peak period, which indicated the deformation and failure of overburden. However, the b value of the microseismic event presented the precursory characteristics of rock stratum fracture that gradually increased and then changed drastically.

Spark Plasma Sintering of SiAlON Ceramics Synthesized via Various Cations Charge Stabilizers and Their Effect on Thermal and Mechanical Characteristics

Oxygen-rich SiAlON ceramics doped with various nanosized metal oxide (MO) stabilizers were synthesized with a view to examine their effect on thermal and mechanical characteristics. The nanosized starting powder precursors comprising Si3N4, AlN, Al2O3, and SiO2 along with oxides of Ba, Y, Mg, La, Nd, Eu, Dy, Er, and Yb as the MO charge stabilizer were employed in developing different SiAlON samples. Ultrasonic probe sonication was utilized to develop a homogenous mixture of initial powder precursors followed by spark plasma sintering (SPS) of the samples at the low temperature of 1500 °C coupled with 30 min of isothermal treatment. Sample compositions (according to general formula of alpha SiAlON: Mm/vv+Si12−(m+n)Alm+nOnN16−n) selected in the present study are represented by m value of 1.1 and n value of 1.6. The synthesized samples were evaluated for their physical behavior, microstructural and crystal structure evolution, and thermal and mechanical characteristics. More specifically, the sintered ceramics were examined by X-ray diffraction and electron microscopy to comprehend and relate the structural characteristics with the densification, thermal conductivity, hardness, and fracture toughness. The high reactivity of the nanopowders and the localized heating provided by SPS resulted in densified ceramics with relative densities in the range of 92–96%. Vickers hardness values were found to be in the range of 12.4–17.0 GPa and were seen to be profoundly influenced by the grain size of the alpha SiAlON (primary) phase. The fracture toughness of the samples was measured to be in the range of 4.1–6.2 MPa·m1/2. SiAlON samples synthesized using Er and Yb charge stabilizers were found to have the highest fracture toughness of 5.7 and 6.2 MPa·m1/2, primarily due to the relatively higher content of the elongated beta phase. While there was no obvious relationship between the thermal conductivity and the alpha SiAlON metal charge stabilizers, the values were seen to be influenced by the grain size of alpha phase where Dy-SiAlON had the lowest thermal conductivity of 5.79 W/m⋅K and Er-SiAlON showed the highest value of thermal conductivity (6.91 W/m⋅K). It was concluded that scientifically selected metal oxide charge stabilizers are beneficial in developing SiAlON ceramics with properties tailored according to specific applications.

Characteristics of Stratum Structure and Fracture Evolution in Stratified Mining of Shallow Buried High-Gas-Thick Coal Seam by Similarity Simulation

The stratified mining of super thick coal seam is a process of repeated disturbance of the top roof, especially in the lower stratification, the upper complex rock layer has a greater settlement space, resulting in great changes in the strata structure and fissure distribution. The main coal seam thickness of Rujigou Coal Mine exceeds 20 m, due to the high gas content of the coal seam, it is prone to spontaneous combustion, and the stratified mining method is adopted. When a small-size section coal pillar (less than 10 m) is used, the complex rock structure evolution and fissure development characteristics during the stratified mining of shallow buried thick coal seam will directly affect the movement of gas transportation between the working face and the goaf and will directly affect the safety of the working face. Taking Rujigou coal mine as engineering background, this paper analyzes the breaking structure, fracture development, and evolution law of overlying strata in different layers and different sections of coal seam when the buried depth is shallow, and the extra-thick coal seam is stratified mining. The results show that in the process of stratified mining, the overlying strata break, in addition to the whole trapezoidal failure structure, will also form a local F type fracture structure, and with the stratified downward mining, the F type fracture structure will continue to move up and disappear until it is compacted. The “V” type and “U” type subsidence characteristics of different strata overburden are presented after mining in stratified working face of extra-thick coal seam, and the subsidence amount is approximately symmetrical distribution along the middle line of goaf. In the mining process of the lower part of the layer, the end broken rock block is easy to slip along the hinge point by the hinged rock beam structure, and the sliding instability occurs. In the process of stratified mining of ultrathick coal seam, the main fissure of overburden is mainly longitudinal fissure, and it is very easy to form through with the upper layer and will finally connect with the surface under the condition of shallow buried depth. The inclined cracks connected with the adjacent goaf are formed above the coal pillar of the section, which becomes the passage of gas migration in the goaf. The research conclusion shows that for the stratified mining of high gas thick coal seam, special attention should be paid to the treatment of the gas on the stratified working face. In addition to the conventional gas treatment measures such as coal seam prepumping, the buried pipe pumping in the mining area can also be adopted, which can effectively reduce the gas concentration of the working surface.

Pore structure evolution characteristics of continental shale in China as indicated from thermal simulation experiments

Organic matter (OM) pores in shale can provide abundant storage space for gas. However, there are different types of OM with different compositions and structures in continental shale, and their pore structure evolution lacks direct observations. In this study, anhydrous thermal simulation experiments in an open system were conducted on a continental Jurassic Ziliujing Formation shale sample with a low initial thermal maturity, taken from an outcrop in the northeastern Sichuan Basin. Changes in the pore structure of a specific OM at different thermal maturities were captured by field emission–scanning electron microscopy (FE-SEM). These FE-SEM images processed by image processing software were combined with N2 adsorption and high-pressure mercury intrusion porosimetry data to help clarify the pore structure evolution characteristics. Our results show that OM developed in Ziliujing Formation shale can be divided into four types based on their morphological characteristics. The pore structure evolution process is closely related to the processes of petroleum generation, migration, and thermal cracking. More specifically, the filling of pores by generated oil at lower temperature caused a decrease of the macropore volume in the shale sample and these filled macropores were released at higher temperature by thermal cracking of oil. In addition, there were no OM pores larger than 10 nm created during thermal simulation experiments, which indicates that the development of such sized OM pores is largely dependent on the original composition and structure of the parent OM.