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In previous practice, the differential strain analysis (DSA) method, relied upon for estimating vertical principal stress to resolve geological stress, has shown limitations in reliability. Drawing upon observations of the Kaiser effect in rock samples, we introduce the Kaiser-differential strain analysis (Kaiser-DSA) method, amalgamating the Kaiser effect with the DSA method to assess in-situ stress differentials. Comparative evaluation with the stress relief method reveals that the Kaiser-DSA method demonstrates minimal relative error and generally consistent orientation of the maximum horizontal principal stress. Utilizing the findings from in-situ stress testing, this investigation scrutinizes the distribution patterns of in-situ stress in Yaojie Mining Area and investigates the causative factors contributing to the prevailing in-situ stress field. The study elucidates that Yaojie Mining Area is subject to the influence of compressive tectonic stress fields, resulting in elevated residual stress. Influenced by the Qinghai-Tibet thrust nappe action and the clockwise shear action of the F19 fault, the geostress field in this region predominantly manifests a strike-slip stress state typified by σH>σv>σh. Furthermore, the heightened differential stress within this locale exacerbates deformation and damage to the surrounding rock mass during mining activities, thereby exacerbating the frequency of dynamic disaster events.

The occurrence of mine water inrushes is common and poses significant hazards in various mining areas throughout China. However, the existing regulations lack of specific engineering geological and hydrogeological exploration guidelines tailored to the water inrush from separation layers (WISL). Exploring the methods of engineering geological and hydrogeological exploration and assessment for the WISL can contribute to further enhancing the prevention and control of mine water disasters in China. This paper begins by examining the mechanism behind WISL in coal mines. It analyzes the geological conditions governing the progression of WISL from its inception to full-scale occurrence and categorizes three prevalent types of WISL in China, i.e., dynamic water inrush, hydrostatic water inrush, and mud and sand-carrying water inrush, all originating from separation layers. Subsequently, it identifies “water source”“channel”“force source”and “material source” as pivotal concealed factors dictating the nature and severity of WISL. Then, the concept of a “inrush separation zone” referring to composite stratigraphic layers situated above traditional water-conducting fractured zones is introduced, where the WISL may transpire during mining activities. Furthermore, it presents a method for delineating “inrush separation zone” in coal mines, outlining exploration stages and specifying crucial investigative focal points. The exploration of water damage in upper strata of coal mine should include two stages: first, the exploration of basic engineering geology and hydrogeological conditions of overlying rock should be carried out to evaluate the possibility of water damage in the exploration area and determine the horizon of potential mining overlying rock ; second, regarding the “inrush separation zone” and “source” layer as the exploration target layer, the special investigation of the hidden disaster factors of the upper layer water damage should be conducted to assess the type and intensity of the water damage in the upper layer. The hydrodynamic conditions and the evolution of overburden fractures are investigated during the mining period. Lastly, a comprehensive forecast evaluation model is proposed and constructed on the coordinated evolutionary mechanisms arising from the interaction of causative factors like “water source”“channel”“force source”and “material source”. This model predicts and evaluates the types, locations, and inflows of water inrush at mining faces before operations commence.

In intersatellite laser communications, the centroiding accuracy of a laser spot is crucial for maintaining steady communication links. However, the systematic error introduced by discrete sampling restricts further improvement of centroiding accuracy when choosing algorithms that are widely used in engineering. Additionally, the ultrahigh computational complexity and multiple-step iterations of the Gaussian fitting (GF) algorithm are unsuitable for real-time implementation, even though the algorithm can achieve the highest centroiding accuracy. In this study, we propose a laser spot centroiding algorithm based on template correlation to simultaneously satisfy the requirements of real-time performance and accuracy. The proposed algorithm evaluates the central location of a laser spot by obtaining the index of the maximum Pearson correlation coefficient (PCC). Simulations performed under different conditions reveal that the proposed algorithm is robust against the interference of background noise and the bad pixels. Moreover, experimental verification is performed based on the implementation on a Field-Programmable Gate Array (FPGA) in real-time, meanwhile its accuracy is on the same level as that of the GF algorithm and better than those of other widely-used algorithms. Therefore, the proposed algorithm is suitable for accurate real-time locating of laser spots in engineering applications of the intersatellite laser communications.

Background: In this study, we aimed to explore whether the SRY-box transcription factor 9 (SOX9) can play protective roles against the occurrence and development of osteonecrosis of the femoral head (ONFH) by regulating the proliferation, apoptosis, and osteogenic differentiation of human bone marrow stromal cells (hBMSCs) via the Wnt/β-catenin pathway. Methods: We used 1600 mg of glucocorticoid (GC) to induce hBMSCs to establish an ONFH cell model and performed various experiments. Reverse transcription-quantitative polymerase chain reaction and western blotting assays were used to determine the expression levels of SOX9 and osteoblast markers, such as the RUNX family transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osterix, Wnt3a, and β-catenin. An ALP detection kit was used to measure the ALP activity. Flow cytometry and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to determine the cell viability. Results: GC treatment decreased the expression levels of RUNX2, ALP, and osterix, suppressed ALP activity, and inhibited SOX9 expression. SOX9 overexpression promoted GC-induced cell proliferation and decreased cell apoptosis. Additionally, hBMSCs were transfected with SOX9-small interfering RNA in GC treatment, and SOX9 knockdown was found to suppress the osteogenic differentiation of cells and decrease their viability. Conclusion: Our results revealed that SOX9 is related to the Wnt/β-catenin pathway in ONFH. Moreover, SOX9 participated in ONFH development by activating the Wnt/β-catenin pathway.

As a typical active noise control algorithm, Filtered-x Least Mean Square (FxLMS) is widely used in the field of audio denoising. In this study, an audio denoising coprocessor based on Retrenched Injunction System Computer-V (RISC-V), a custom instruction set extension was designed and a software and hardware co-design was adopted; based on the traditional pure hardware implementation, the accelerator optimization design was carried out, and the accelerator was connected to the RISC-V core in the form of coprocessor. Meanwhile, the corresponding custom instructions were designed, the compiling environment was established, and the library function of coprocessor acceleration instructions was established by embedded inline assembly. Finally, the active noise control (ANC) system was built and tested based on Hbird E203-Core, and the test data were collected through an audio analyzer. The results showed that the audio denoising algorithm can be realized by combining a heterogeneous System on Chip (SoC) with a hardware accelerator, and the denoising effect was approximately 8 dB. The number of instructions consumed by testing custom instructions for specific operations was reduced by approximately 60%, and the operation acceleration effect was significant.

With the gradual increase of coal production capacity, the issue of water hazards in coal seam roofs is increasing in prominence. Accurate and effective prediction of the water content of the roof aquifer, based on limited hydrogeological data, is critical to the identification of the central area of prevention and control of coal seam roof water damage and the reduction of the incidence of such accidents in coal mines. In this paper, we establish a prediction model for the water abundance of the roof slab aquifer, using a PSO-GA-BP neural network. Our model is based on five key factors: aquifer thickness, permeability coefficient, core recovery, number of sandstone and mudstone interbedded layers, and fold fluctuation. The model integrates the genetic algorithm (GA) into the particle swarm optimization (PSO) algorithm, with the particle swarm optimization algorithm serving as the primary approach. It utilizes adaptive inertia weight and quadratic optimization of the weights and thresholds of the backpropagation neural network to minimize the output error threshold for the purpose of minimizing output errors. The prediction model is applied to hydrogeology and coal mine production for the first time. The model is trained using 100 data samples collected by the Surfer 13 software. These samples help to accurately predict the unit inflow of water. The model is then compared with traditional forecasting methods such as FAHP, BP, and GA-BP neural network models to determine its efficiency. The study found that the PSO-GA-BP neural network model accurately predicts aquifer water abundance with higher precision. The root mean square error (RMSE) of the test set is determined to be 8.7 × 10−4, and the fitting result is measured at 0.9999, indicating minimal error with actual values of the sample. According to the prediction results of the test set, the water abundance capacity of the No. 7 coal mine in Hami Danan Lake is divided, and it is found that the overall difference between the results and the actual value is small, which verifies the reliability of the model. According to the results of the water abundance division, strong water abundance areas are mainly concentrated in the third-partition area. This study provides a new method for the prediction of aquifer water abundance, improves the prediction accuracy of aquifer water abundance, reduces the cost of coal mine production, and provides a scientific evaluation method and a theoretical basis for the prevention and control of water disasters in coal seam roofs.

With the development of space laser communication and the planned deployment of satellite Internet constellations, there is a growing demand for microminiature laser communication terminals. To meet the requirements of size, weight and power (SWaP), miniaturized terminals require smaller drive components to complete on-orbit scanning and capture, which must be fast and efficient to enable satellite laser communication networks. These miniaturized laser communication terminals are highly susceptible to the impact of the initial pointing accuracy of the laser beam and microvibrations of the satellite platform. Therefore, this paper proposes a laser scanning-capture model based on a Micro-electromechanical Systems (MEMS) micromirror that can provide a fast, large-scale scanning analysis. A scanning overlap factor is introduced to improve the capture probability under the influence of microvibrations. Finally, experimental analysis was carried out to verify the effectiveness of the proposed model, which can establish a theoretical basis for future ultra-long-distance microspace laser communication.

Rockburst is one of the main dynamic disasters in coal mines; it is of great significance to accurately evaluate the risk zoning of rockburst for mine safety construction and pressure relief design. Taking the Gaojiapu coal mine in the Bingchang mining area of Shaanxi Province as the study area, this paper quantifies the complex geological structure based on fractal theory and establishes the zoning evaluation model of rockburst risk index in the mining area by LS-FAHP-CRITIC method in combination with the distribution characteristics of field stress field, the distribution of geological structure, and the sedimentary environment of coal seam overburden. A new evaluation method of rockburst risk zoning in the coal mine is proposed, and the rockburst risk in the study area was evaluated. The results show that the dangerous areas in the study area are widely distributed, mainly in the area near the structure with high maximum horizontal principal stress. On the basis of the actual rockburst of the Gaojiapu coal mine, the areas where rockburst occurs are all located in dangerous area and high dangerous area, which verifies the accuracy and rationality of the zoning evaluation results of the new method. This method can be used to guide the safety production of similar mines or adjacent coalfaces.

Circular RNA circ_0136474 is a new contributor of human osteoarthritis (OA) by suppressing chondrocyte proliferation. However, its role and mechanism in OA chondrocyte injury remain ill defined. Herein, we performed real-time quantitative PCR to detect RNA expression of circ_0136474, microRNA (miR)-766-3p, and DNA methyltransferase 3A (DNMT3A) and utilized Western blotting to measure protein expression of DNMT3A, matrix metalloproteinase-1 (MMP1), MMP13, collagen II, proliferating cell nuclear antigen (PCNA) and B cell lymphoma (Bcl)-2, and Bcl-2-associated X protein (Bax). Direct interaction between miR-766-3p and circ_0136474 or DNMT3A was confirmed by bioinformatics algorithms, dual-luciferase reporter assay, and RNA immunoprecipitation. Functional experiments including cell counting kit-8 assay, flow cytometry, and special assay kits were employed to measure oxidative injury in interleukin (IL)-1β-induced OA-like chondrocytes. First, IL-1β administration induced cell viability inhibition, collagen II suppression, and promotion of MMP1 and MMP13 in human chondrocyte CHON-001 cells. Expression of circ_0136474 and DNMT3A was upregulated, and miR-766-3p was downregulated in human OA cartilages and IL-1β-induced CHON-001 cells. Functionally, both blocking circ_0136474 and upregulating miR-766-3p could rescue cell viability and levels of PCNA, Bcl-2, reduced glutathione (GSH), and total superoxide dismutase (SOD), and attenuate apoptosis rate and levels of Bax, reactive oxygen species (ROS), and lipid peroxidation malondialdehyde (MDA). Mechanically, circ_0136474 served as miR-766-3p sponge to govern miR-766-3p-targeted DNMT3A expression. Accidently, restoring DNMT3A counteracted the miR-766-3p upregulation role, and silencing miR-766-3p weakened circ_0136474 knockdown effect in IL-1β-induced CHON-001 cells. In conclusion, exhausting circ_0136474 could mitigate OA chondrocyte oxidative injury through regulating miR-766-3p/DNMT3A axis.

Low frequency oscillation is an important attribute of human brain activity, and the amplitude of low frequency fluctuation (ALFF) is an effective method to reflect the characteristics of low frequency oscillation, which has been widely used in the treatment of brain diseases and other fields. However, due to the low accuracy of the current analysis methods for low frequency signal extraction of ALFF, we propose the Fourier-based synchrosqueezing transform (FSST), which is often used in the field of signal processing to extract the ALFF of the low frequency power spectrum of the whole-time dimension. The low frequency characteristics of the extracted signal are compared with those of FSST and fast Fourier transform (FFT) through the resting-state data. It is clear that the signal extracted by FSST has more low frequency characteristics, which is significantly different from FFT.

Multilevel oligomers, gradually increasing in size, were generated systematically by using the tetradecker sandwich reaction where double-decker cobaltacarborane aminos are sandwich-complexed to a central metal ion to develop a stable trimetallic complex. This reaction was employed in the case of double-ended bis(cobaltacarborane) anionic complexes. The stagewise building of air-stable multisandwich oligomers and polymers that are soluble in organic solvents can be facilitated by using the appropriate synthons such as bis(cobaltacarborane) complexes bridged by fulvalene or 1,4-bis(tetramethylcyclopentadienyl).

The formation and characterization of the tetracarbon metallacarborane clusters Cp*2Co2Et4C4B6H4X2 were reported. These carbon-rich compounds have an open Co2C4B6 12-vertex cage structure that is a fragment of a 16-vertex Td closo polyhedron. It was shown by X-ray crystallography that the dimer (Cp*Co(Et2C2B3H3))2 have an edge-fused structure. The implications of the formation and structures of the fused and partially fused products are discussed in terms of multidecker stacking mechanisms and skeletal electron-counting theory.

The double-decker stacking reactions of the bridge-deprotonated Cp*Co(2,3-Et2C2B3H3-5-X)1- complexes, where X = Cl, Br, CH3, C(O)CH3, CH2C-triple bond-CCH3 or H and Cp* = eta5-C5Me5, with cobalt(II) and nickel(II) halides in THF yield the diamagnetic Co(III)-Ni(IV)-Co(III) complexes (Cp*Co(2,3-Et2C2B3H2-5-X))2Ni and the paramagnetic Co(III)-Co(IV)-Co(III) complexes (Cp*Co(2,3-Et2C2B3H2-5-X))2Co. These reactions involve the metal complexation of the double-decker substrates and the workup on silica in air.

Cyclic voltammetry, NMR and ESR spectroscopy were used in the study of the electrochemical behavior of the ferracarborane clusters Cp*FeIIH(Et2C2B4H4) andCp*FeIII(Et2C2B4H4) and the phenylene-linked diiron species (Et2C2B4H4)FeIIH(C5Me4-C6H4-C5Me4)FeIII(Et2C2B4H4), ((Et2C2B4H4)FeH(C5Me4))2C6H4 and ((Et2C2B4H4)FeIII(C5Me4))2C6H4. Results showedthe importance of the R2C2B4H4(super 2-) ligands as organometallic synthetic agents and as mono- and dimetallic complex electronic stabilizers.

A series of imide resins were prepared using 2,3,3',4'-oxydiphthalic dianhydride, 4-phenylethynylphthalic anhydride, and aromatic diamines (1, 3-bis(3-aminophenoxy), 3,4'-oxyaniline, 2,2'-bis (trifluoromethyl) benzidine, and m-phenylenediamine) as starting materials. These imide oligomers were characterized by means of Fourier transform infrared spectroscopy, differential scanning calorimetry, intrinsic viscosity measurements, and rheological measurements. Some of these oligomers exhibited low (<1 Pa·s at 250°C) and stable (>2 h at 250°C) melt viscosity, which was highly desirable for resin transfer molding process. Thermosetting polyimides (PIs) were then produced from these oligomers via thermal cross-linking reaction of phenylethynyl group. The properties of the thermosets were studied using tensile and flexural testing, dynamic mechanical thermal analysis, and thermogravimetric analysis. The cured PIs exhibited a good combination of thermal and mechanical properties, with a tensile strength of 31-76 MPa, flexural strength of 38-142 MPa, glass transition temperatures of 233-358°C, and 5% weight loss temperatures of 540-545°C under nitrogen atmosphere. [ABSTRACT FROM AUTHOR]

Illustrates a synthetic approach to a two-dimensional grid polymer. Requirements for the synthesis; Polymerization; Analytical techniques for local structure; Results of linear coupling of carboranyl terminals; Description of connector structure; Tentacle attachment and removal; Infrared spectra of the connectors.