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In order to improve the detection efficiency and anti-interference capability of single photon lidar, we proposed chaos single photon (CSP) lidar based on true random coding in previous research. However, compared with traditional pulse accumulation single photon (PASP) lidar, pseudo-random single photon (PRSP) lidar and other true random encoding lidars, the advantages of CSP lidar have not yet been proven. In this paper, comparison research is carried out between PASP lidar, PRSP lidar and true random coding lidars. Comparative results demonstrate that the CSP lidar is an efficient and robust system. It is believed that the comparative study will provide theoretical guidance for practical applications of single photon lidar. [ABSTRACT FROM AUTHOR]

• Taking advantage of multiple gravity, seismic, magnetic and thermal data. • Calculation of the three-dimensional temperature, velocity and viscosity characteristics of the north Sulawesi region. • Exploring the dynamic causal mechanism of the Una-Una volcanic island. The Una-Una Volcanic Island is an active and isolated island, and its deep structure and dynamic causal mechanism have yet to be fully understood. The island is situated in Tomini Bay, between the north and east arms of Sulawesi Island in Indonesia. Around 5 Ma, the Sula Islands collided with the east arm of Sulawesi Island, which caused the subduction and retreat of the North Sulawesi Trench. Additionally, a sinistral strike-slip of roughly 4 cm/a initiated at the Palu-Koro fault on the western side of Sulawesi Island, ultimately leading to the formation of the isolated Una-Una Volcanic Island in Tomini Bay. Here, we utilized gravity, seismic, magnetic, and heat flow data to calculate the geophysical characteristics of three-dimensional temperature, velocity, and viscosity of the northern Sulawesi region. The results of our research showed that the crust in the northern region of Sulawesi Island is primarily characterized by brittle deformation. However, the presence of a southward-inclined weak layer in the crust, which resulted from the subduction of the North Sulawesi Trench, caused the region between the terrain and the Moho surface to exhibit a combination of brittle and ductile deformation. The weak zone in the crust in the northern region of Sulawesi Island is the primary controlling factor for the development of sinistral strike-slip. The uplift of the crustal weak area below the Una-Una Volcanic Island was caused by the southward subduction of the North Sulawesi Trench and the northward push of the Banggai-Sula microblock, ultimately leading to the formation of the Una-Una Volcanic Island in Tomini Bay. [ABSTRACT FROM AUTHOR]

The chemical immobilization of silane on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) surface is promising in improving both osseointegration and antibacterial activity, however, the effect of low temperature degradation (LTD)-induced the tetragonal (t) to monoclinic (m) phase transformation on the chemical bonding and continuous bioactivity remains unclear. In this study, 3-aminopropyltriethoxysilane (APTES) and 3-mercaptopropyltrimethoxysilane (MPTS) were grafted on the Y-TZP surface. Quantum chemistry revealed that Zr– O –Si bonds formed by t/m -ZrO 2 both had a strong tendency to undergo hydrolysis in acidic or neutral environments, but were stable in alkaline environments. Inductively coupled plasma mass spectrometry showed that the release of Si increased during weeks 1–3 on both APTES- and MPTS-grafted surfaces, then decreased rapidly on MPTS-grafted surface while maintained a sustain release on APTES-grafted surface until week 4; in particular, the hydrolysis of Zr– O –Si bonds did not accelerated by LTD. X-ray photoelectron spectroscopy showed that LTD-induced reductions in Zr– O –Si bond contents on APTES- and MPTS-grafted surfaces were 0.63% and 1.79%, respectively. In vitro MC3T3-E1 cell experiments confirmed that APTES- and MPTS-grafted Y-TZP surfaces maintained similar adhesion and proliferation before and after LTD. Scanning electron microscopy, laser confocal scanning microscopy, and spread plate assay findings showed favorable anti - Porphyromonas gingivalis (P. gingivalis) effects induced by APTES- and MPTS-grafted t/m -ZrO 2 surfaces. Thus, APTES and MPTS both provide LTD-stable and hydrolysis-stable chemical bonding for Y-TZP implants, and t-m phase transformation does not cause detectable effects on Y-TZP bioactivity. [ABSTRACT FROM AUTHOR]

• A thermal evolution model is proposed to explain the activity of the Halmahera volcanic arc. • Our results can explain why there are magmatic gaps and volcanic arc migration during subduction and rollback. • The thermal simulation results show that a smaller subduction rate or a larger convergence rate are favorable to the occurrence of island arc magmatism. The Halmahera volcanic arc has experienced intermittent volcanic activity and location migration since the Pliocene. Two factors affect the volcanic arc magmatism. One is the dehydration depth of hornblende in the oceanic crust and serpentinite in the lithospheric mantle in the subducted slab. The other is the subducted slab and mantle wedge temperature structure, controlled by the subduction rate and plate convergence rate. Thermal simulation results show that conditions are favorable to the occurrence of island arc magmatism at a lower subduction rate with the same convergence rate, or at a higher convergence rate with the same subduction rate. The Miocene–Pliocene favored the occurrence of island arc magmatism in the high temperature region, because there was a lower subduction rate beneath the Halmahera volcanic arc. After the Middle Pliocene, there was cessation of volcanic activity and a volcanic gap, with subsidence of the mantle wedge high temperature region, increase of the partial melting depth, and decrease of the melting amount, because there was an increased subduction rate beneath the Halmahera volcanic arc and a decreased westward convergence rate of the eastern microplate fragments. In the Holocene, the Halmahera arc moved to a new location and resumed volcanic activity. It is because continuous arc–arc collision blocked the westward movement of the Halmahera volcanic arc, the relative convergence rate of the eastern microplate increased, which resulted in the formation of a high temperature region favorable to island arc magmatism. [ABSTRACT FROM AUTHOR]

• The structure of dead-end pore is established by artificial pore technology. • Study on the effect of dead-end pore size change on seepage characteristics. • Study the influence of the connectivity on the seepage of dead-end pores. Coal contains a large number of internal pores and fractures that directly affect the seepage process of water injected into it. But the influence of dead-end pores on the seepage process is incompletely explored. To this end, we constructed structure models of "fractures and dead-end pores" in gas coal and non-stick coal with different pore sizes and connectivity based on computed tomography with 3-dimentional reconstruction and artificial pore technology. We simulated the dynamic seepage process of water injected into different coals using the Navier-Stokes equation, and obtained the distribution characteristics of water seepage in the "fractures and dead-end pores" structure at initial velocity of 0.03 mm/s, 0.04 mm/s, 0.05 mm/s and 0.06 mm/s for models with different pore sizes. The results showed that the seepage velocities in natural pores, fractures and artificial dead-end pores all exhibited a trend of "decreasing after increasing and stabilizing" with the increase of time. We then introduced the concepts of "peak velocity" and "stable flow velocity" to describe unsteady seepage conditions. In the dead-end pores, with the increase of the equivalent size, the peak velocity of the two different coals showed different variation patterns and the stable flow velocity increased nonlinearly. Changes in pore sizes affected not only the seepage characteristics in the pores, but also the stable flow velocity in the fractures. Specifically, as the pore size increased, the stable flow velocity changed from "gradually increasing" to "gradually decreasing". Changes in connectivity affected the stable flow velocity in the "fractures and dead-end pores". [ABSTRACT FROM AUTHOR]

In this work, four novel refractory high entropy alloys (RHEAs) of the Ti-Zr-V-Mo system have been developed and characterized by experiments. Except for the RHEA of Ti 0.5 ZrVMo with phase constituents of bcc + pm-3n + Laves (C15 type), the phase constituents in the as-solidified condition of all the other three RHEAs can be denoted as bcc1 + bcc2 + Laves (C15 type). All four alloys exhibited typical dendrite morphology with coarse dendrites and thin inter-dendritic regions. Besides, there were certain small-sized precipitated particles dispersed in the inter-dendrite matrix. In TiZrV 3 Mo, bcc structured solid solution phases of (TiMoV) and (TiZrV) as well as one C15 Laves phase of (MoV) Zr were confirmed. The equiatomic RHEA of TiZrVMo exhibited a yield strength of 1323.0 MPa, compressive strength of 1521.9 MPa and a compressive strain of 4.5%, also with double bcc structured solid solution phases of (TiMo) and (TiZr) as well as the Laves precipitate of Zr 0.5 Ti 0.5 Mo 2. The multi-phase RHEAs with solid solutions and minor precipitates with excellent performances by deformation incompatibility between phases, provide a certain reference for the composition design and the industrial development of RHEAs in practical applications. • Four RHEAs of Ti-Zr-V-Mo were developed with multi-phases including bcc matrix. • All four alloys exhibited coarse dendrite morphology with thin inter-dendritic regions. • The equiatomic TiZrVMo exhibited high strength of 1522 MPa and deformation strain of 4.5%. • TiZrVMo included two bcc structured solid solution phases and one Laves phase. [ABSTRACT FROM AUTHOR]

• Numerical simulation of forearc collision and thrusting. • Exploring the causal mechanism of the Sangihe Forearc thrust. • Plate boundary stress and arc volcanic loading are non-negligible factors on thrusting. • Causal mechanism difference in Sangihe Forearc thrust in north and south parts of Molucca Sea subduction zone. The Molucca Sea subduction zone contains an interesting geological phenomenon: the Sangihe Forearc Thrust (SFT). At 10 Ma, divergent double subduction (DDS) in the Molucca Sea was initiated, resulting in the convergence of the Sangihe and Halmahera forearcs, and their subsequent collision at 2 Ma. Associated with this collision, the Sangihe Forearc was thrust over the Halmahera Forearc. Currently, the causal mechanism associated with the SFT remains unknown. Here, we simulate the structural and morphological characteristics of forearc collision and thrusting within this DDS zone under different conditions, calculate the temperature structures and characteristics of magmatic activity under the Sangihe and Halmahera arcs, and explore the causal mechanism of the SFT. Our results demonstrate that plate boundary stress and volcanic loading are two non-negligible factors affecting the forearc thrust. We identify different causal mechanisms for the SFT in the northern and southern parts of the asymmetric DDS zone in the Molucca Sea. In the northern part of the DDS zone, the SFT is primarily caused by plate boundary stress, which is mainly generated by the southwestward subduction of the Philippine Sea Plate. In the southern part of the DDS zone, the SFT is mainly caused by the effects of differential volcanic loading. The effect of volcanic loading on the Halmahera Forearc is noticeably stronger than that on Sangihe Forearc, resulting in more severe vertical deformation and subsidence of the former. Finally, the less vertically-deformed Sangihe Forearc was thrust over the Halmahera Forearc under the action of horizontal arc-arc collision extrusion. [ABSTRACT FROM AUTHOR]

• Precise description of coal fractal characteristics based on digital core technology. • Quantitative description of coal pore structures and fractal characteristics. • Fractal and seepage characteristics of pores in different pore sizes are analyzed. The pores/fractures are places for gas migration and storage in coal. Their structure complexity will directly influence the pore structure parameters and gas seepage properties of coal. Therefore, we selected 6 low-rank coal samples and quantitatively studied these influences utilizing the high-resolution micro computed tomography (μCT) and fractal theory. The total pore structure and connected pore structure parameters of 6 samples were acquired from three-dimensional (3D) reconstruction of CT images. The fractal dimensions of total pore structures (D f), solid structures (D s) and connected pore structures (D c) were calculated using 3D box-counting method. The relationship between D f and porosity was analyzed through the 3D total pore model, and the relationships between D c and connectivity as well as permeability were analyzed through the 3D connected pore model. The results show that D f , which is between 2.10 and 2.43, could accurately describe the fractal characteristics of coal and the solid structure of coal is not fractal. The porosities of the 6 samples are between 3.33% and 12.18% and their relationship with D f can be defined by a monotonically increasing power function. The larger the D f is, the larger the porosity of the tested coal sample. D c is between 2.28 and 2.32, the connectivity is between 0.54 and 0.83, and the permeability is in the range of 1.76–11.63 × 10−8 m2 (except samples 1 and 6). D c is negatively correlated with connectivity and permeability and its relationship with connectivity and permeability can be represented by the quadratic function and monotone decreasing power function, respectively. [ABSTRACT FROM AUTHOR]

The porous structure of coal directly determines its gas transport property. The fluid flow behavior of coal is one of the key science questions that will influence the coal energy industry. In this study, the influence of real coal macropore structure on the fluid flow through coal was studied through 3-D coal structure reconstruction by the CT images. Based on the reconstructed coal structure, the micron-scale structure parameters were quantitatively analyzed. A newly programmed Matlab code was established to find the volume fractal dimension, obtain the relationship between porosity/permeability of coal and volume fractal dimension, and estimate the tortuosity fractal dimension by using the 3-D box dimension algorithm. The results show that the volume fractal dimensions of 6 coal samples range from 2.25 to 2.79 and the tortuosity fractal dimensions of capillaries range from 2.15 to 2.73. The 3-D coal structure cannot only quantitatively estimate the real porosity of the coal, but it can be used to characterize the complexity of coal's porous structure through mean deviation of surface porosity. It can be clearly seen from the reconstructed coal that coal specimen-C3 is highly heterogeneous because it has complex pore structure as well as wider pore size distribution and the highest mean deviation of the surface porosity. The volume fractal dimension can be used to quantitatively define the complexity of pores. The larger the porosity of coal, the greater the fractal dimension. The permeability and porosity of coal are negatively correlated with the volume fractal dimension. The tortuosity fractal dimension can effectively characterize coal permeability, but it weakly correlates with coal porosity. The outcome of this study helps to understand the structure-based flow characterization and gas transport behavior in heterogenous coal which will have the implication of the gas extraction from coalbed methane reservoirs and coal mine gas drainage. [ABSTRACT FROM AUTHOR]