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Guizhou has many coal seams, thin coal seams, many gangues, and rapid lithology changes. Its complex strata characteristics increase the difficulty of fracturing CBM wells. Taking coalbed methane well in Jinjia Coal Mine as an example, we research the risk of complex formation fracturing and fracturing technology, and explore the adaptability of secondary pump-stop fracturing technology under stress disturbance. Engineering practice show that the lithology of coal measures in Jinjia Coal Mine has complex changes, and the lithology can be divided into 5 combination modes; multi-coal and multi-layered coal seams adopt methods such as “avoidance, expansion, selective injection, continuous injection, and directional perforation”, which can reduce the difficulty of fracturing construction. Multi-seam combined layer fracturing and multi-layer coal seam fracturing reform adopted the secondary stop pump fracturing technology, promoted the formation stress redistribution and fracture diversion, and improved the effect of reservoir fracturing reform; two coalbed methane wells in the study area implemented a secondary pumping-off fracturing process. The fracturing construction curve, pressure changes after pumping-off, and gas production effect all show that the fracturing process has a better effect on reservoir reconstruction.

In order to study the characteristics of porosity, permeability and stress sensitivity of middle rank coal reservoir in Tucheng syncline and their influence on coalbed methane exploitation, coal core samples of coal seams 1#, 3#, 5#, 15#, 17#, 291# and 292# in Tucheng syncline were collected. Based on the overburden porosity and permeability test, the variation law of porosity and permeability with effective stress of each coal reservoir is compared, and the sensitivity of effective stress of each coal reservoir is analyzed by using the parameters of porosity stress damage rate, permeability stress damage rate and permeability curvature. The results show that: with the increase of effective stress, the coal reservoir porosity and gas permeability were negative exponent; the stress sensitivity coefficient of test coal reservoir is 0.035-0.073 MPa-1, and the stress sensitivity regression coefficient of 3# coal sample is the largest; the stress damage rate of porosity increases with the increase of effective stress, and the stress damage rate of 3# coal sample with shallow burial depth is relatively large. The permeability stress damage rate increases exponentially with the increase of effective stress, and the permeability damage rate of 3# coal sample is obviously larger than that of other coal samples. The permeability curvature of coal reservoir decreases exponentially with the increase of effective stress.Under the same effective stress, the stress sensitivity of 3# coal seam is greater than that of 5#, 15# and 29# coal seam, and the stress sensitivity of 1# and 17# coal seam is the weakest.

Taking coal-bed methane wells in Jinjia Mining Area as an example, the characteristics of coal-measure formation lithology changes and their influence on the quality control of CBM well drilling and completion are summarized, drilling construction parameters are optimized, and the drilling of coal seams is less harmful and more efficient. Engineering practice shows that the coal seams and roof and floor lithologies in the coalbed methane exploration area of Jinjia Mining Area are complex, mainly sandstone, mudstone, sandy mudstone, and argillaceous sandstone. The combined distribution of coal seams and roof and floor can be divided into 5 structural models; the coal-bearing strata of Longtan Formation in exploration area is suitable for drilling with medium-low drilling pressure of 20-30 kN, small displacement of 15-20 L/s, and medium-high speed drilling to avoid excessive drilling pressure caused by excessive well inclination; cement slurry density for cementing construction is not easy to exceed 1.85 g/cm3 to avoid the excessive density of cement slurry from invading the near-well zone and causing reservoir damage.

The traditional recursive least squares (RLS) algorithm is limited in highly dynamic and noisy underwater channels. To overcome this, we introduce the time-varying Gaussian sliding window-based RLS (VGSRLS) algorithm, designed for enhanced channel tracking. The VGSRLS algorithm adaptively adjusts window length based on the signal's instantaneous frequency variation. A rotation matrix reorients the Gaussian window toward the highest signal-to-noise ratio (SNR) direction, increasing channel tracking accuracy. Further, the algorithm adapts the Gaussian window shape along the highest SNR direction by combining dynamic window length and anisotropic adjustments, effectively suppressing noise from other directions and enhancing SNR. Simulation results confirm that VGSRLS achieves superior channel estimation accuracy, showing reduced mean squared deviation (MSD) under typical noise conditions in underwater environments compared to the SRLS-DCD algorithm. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to analyze the clinicopathological characteristics and survival outcomes of tongue cancer in the pediatric population, a topic with limited existing data, using a population‐based cohort. Methods: Pediatric patients diagnosed with tongue cancer from 1975 to 2018 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Survival rates were assessed using Kaplan–Meier analysis. Univariate survival analysis was conducted with the log‐rank test, while multivariate analysis involved Cox proportional‐hazards regression to identify factors influencing overall survival (OS). A predictive nomogram was developed based on Cox regression findings. Results: In total, 97 pediatric patients with tongue cancer were identified, with a median age at diagnosis of 15 years (range: 1–19 years). Tumors were classified as squamous cell carcinoma (45.4%), rhabdomyosarcoma (RMS) (13.4%), and others (41.2%). Of the patients, squamous cell carcinoma was more common in older children, whereas rhabdomyosarcoma was more common in younger children. The Cox proportional hazard regression revealed that histology and surgery were significant independent predictors of overall survival. The chance of death increased with no surgery. Moreover, patients with squamous cell carcinoma or rhabdomyosarcoma have a poorer survival percentage than patients with other subtypes. Conclusions: Tongue cancer in children is rare and associated with poor survival outcomes. This study highlights the significance of tumor histology and surgical intervention in determining overall survival, offering valuable insights for clinical decision‐making in pediatric tongue cancer. [ABSTRACT FROM AUTHOR]

This document discusses the optimization of operating conditions for battery thermal management systems (BTMS) in electric vehicles. The operational temperature of lithium-ion batteries has a significant impact on their efficiency and safety. The ideal temperature range for efficient operation is 20-40 °C, with a recommended temperature difference between batteries of no more than 5 °C. Researchers have explored various methods to regulate battery temperature, including using phase change materials (PCM) and heat dissipation techniques. These studies aim to improve battery performance in both low and high-temperature environments and prevent thermal runaway. The findings from these studies can contribute to the development of more efficient BTMS for lithium batteries. [Extracted from the article]

The controlled motion of droplets in microfluidic chips is a preliminary requirement to realize their functions. The influence of the expansion section on the droplet motion is mainly investigated in the T-junction. The droplet dynamic characteristics are analyzed at the junction and the applicable flow rate of the expansion section is explored. The expansion section can reduce the entered length and motion time of the droplet when droplets flow into the channel with it, and finally avoid the possibility of droplet splitting. Even under a large difference of the branch flow rate, the expansion section can direct the droplet into its located channel. It is found that with the increase in continuous phase flow rate, the effect of the expansion section on the droplet motion behavior is gradually weakened until it disappears. Moreover, the critical conditions of it can be obtained by theoretical calculation. The expansion section can direct droplet motion in both symmetric and asymmetric junctions. However, it is mainly achieved by influencing the interfacial tension of the droplets in the symmetric junction, while the key force is related to the droplet motion in the asymmetric junction. Specifically, the expansion section influences the differential pressure force to direct the droplet in the flow into the side branch (with expansion section) mode, but it varies the interfacial tension of the droplet in the flow into the main branch mode. [ABSTRACT FROM AUTHOR]

In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.