Utilizing the PyroSim numerical simulation method, a comprehensive study was conducted to investigate the mechanism of the smoke pull-through phenomenon in a top-central exhaust system under conditions of counter-flowing jets, with a focus on the effects of various exhaust powers. Changes in smoke layer thickness, temperature distribution, and airflow velocity within tunnels were investigated under conditions of enhanced exhaust efficiency. Critical exhaust efficiency thresholds associated with smoke pull-through phenomena were identified across varying heat release rates of fire sources. Furthermore, the critical Froude number for smoke pull-through in centralized exhaust systems was established under counter-flowing jet conditions, along with the critical exhaust rate coefficient required to prevent such occurrences. The findings revealed that as the exhaust power increased, the exhaust port R3, located farthest from the fire source, was the first to experience smoke pull-through, followed by R2, while R1 remained unaffected. An increase in the heat release rate of the fire source led to a corresponding rise in the critical exhaust power threshold for smoke pull-through. A moderate increase in exhaust power could improve exhaust performance; however, exceeding a specific critical value would trigger smoke pull-through, thereby reducing exhaust efficiency. At heat release rates of 20 MW, 30 MW, and 50 MW, the critical exhaust powers were identified as 80 m³/s, 100 m³/s, and 150 m³/s, respectively, with optimal exhaust powers of 50 m³/s, 70 m³/s, and 110 m³/s. Furthermore, the critical Froude number for smoke pull-through was determined to be 35, and the critical exhaust rate coefficient was 0.8.These findings provide a theoretical basis for optimizing the design of exhaust systems, enhancing efficiency, and promoting energy conservation.

In the southern Great Xing'an Range, the Xishala area exposes a substantial amount of Mesozoic strata of Xinmin Formation (J₂x) and Manketouebo Formation (J₃m). However, due to the presence of rhyolite in the rock association, it is easy to confuse the stratigraphic division and lead to disputes of the stratigraphic attribution of rhyolite. Therefore, zircon U-Pb dating and geochemical characteristic analysis of the rhyolites were conducted, and stratigraphic sections of the Xinmin and Manketouebo Formations were compared to explore the formation age, tectonic setting, and stratigraphic attribution of the rhyolites. The results indicate that the geochemical characteristics of the riolites in Xishala area are high SiO₂ content (The value of mean is 75.74%.), rich alkali content [mean(Na₂O+K₂O)=7.69%] and low Mg and Ca content, belonging to peraluminous and high-K calc-alkaline series. The Chondrite-normalized REE pattern is right-dip type, with relative enrichment of LREE and relative depletion of HREE, the value of (La/Yb)_Nis between 10.61~14.21 and strong negative Eu anomaly (The value of δEu is between 0.44~0.53.). LILE(large ion lithophilic elements) such as Rb, Ba and K are relatively enriched, while HFSE(high field strength elements) such as Nb, Ta and Ti are relatively depleted, indicating that the magma originated from crustal materials. The LA-ICP-MS zircon U-Pb dating results show that the age of the rhyolite is (167.7±2.6) Ma, belonging to the Middle Jurassic, and it formes in the extensional tectonic action after the closure of the Mongolian-Okhotsk ocean. Based on the comparative study of regional geology and sectional rock assemblage types, the rhyolite belongs to the Manketouebo Formation.

Formation RF (radio frequency) systems compatibility is an important comprehensive ability that affects the survival and combat effectiveness of aircraft formation. It needs to be effectively assessed and verified through flight tests, and simulation can further optimize test design and improve test efficiency. Thus, a flight test method for formation RF systems compatibility based on simulation prediction was proposed. Firstly, the development trend of RF compatibility and is its capability requirements were summarized and analyzed. Secondly, a simulation model of formation RF systems compatibility based on interference conflict was proposed, and a flight test method of formation RF systems compatibility based on the interference conflict distance from simulation analysis was established. Finally, simulation analysis and flight profile design were conducted for a typical formation RF compatibility test. This study has provided an effective method for the test profile design and flight verification of formation RF systems compatibility.

Vehicle performance and energy efficiency can be significantly enhanced by PGS-FHEP (planetary gear set based flywheel hybrid electric powertrain). The main components were designed and matched, and DP (dynamic programming) control strategy was introduced based on ECMS (equivalent consumption minimization strategy) to obtain the optimal SOC (state of charge ) trajectory. The initial optimal equivalent factor obtained by GA (genetic algorithm) was adjusted in real time to ensure that the actual SOC trajectory is consistent with the optimal trajectory. Thus, a real-time A-ECMS (adaptive equivalent consumption minimization strategy) was built, and the three control strategies were simulated and compared under CLTC-C (China light-duty commercial vehicle test cycle) condition. The results show that under the control of A-ECMS, compared with the traditional ECMS, the comprehensive energy consumption of FHEV (flywheel hybrid electric vehicle) equipped with the PGS-FHEP is reduced by 2.51%, and the control effect is closer to the DP control strategy. The energy recovery rate of the PGS-FHEP is 57.72%, of which 23.64% is recovered in the form of mechanical energy. In addition, the participation of the flywheel significantly reduces the peak power of the battery during energy recovery process.

ABR(auditory brainstem response) is an objective method for detecting hearing loss, which is widely used in clinical practice, and its waveform characteristics are influenced by stimulus parameters. There are stimulus artifacts in ABR measured using unipolar stimulus, and alternating polarity is currently the only way to eliminate stimulus artifacts. However, considering the physiological differences in the effects of stimuli with different polarities on the auditory system, alternating polarity stimuli may lead to latency jitter in the induced ABR. Therefore, a new method was proposed to eliminate stimulus artifacts-the method of division and sum polarity, which first used positive and negative stimuli separately and then superimposed the two responses induced. The subjects with normal hearing were recruited, and their data that the click ABRs under four polarity ways (positive polarity, negative polarity, alternating polarity, division and sum polarity), as well as the tone-burst ABRs at five frequencies under two polarity ways (alternating polarity and division and sum polarity) were compared, with a focus on their waveform differentiation and latency differences. The results show that the difference in click ABRs under different polarity ways is insignificant, indicating that it is not sensitive to stimulus polarity. The waveform of low-frequency tone-burst ABRs is better under division and sum polarity than under alternating polarity, indicating that the low-frequency tone-burst ABR is more sensitive to stimulus polarity, and the sensitivity decreases with the increase of stimulus frequency. Based on the analysis of the above results, it is recommended to use unipolar stimulus for the click ABR, and the division and sum polarity method for the tone-burst ABR. The feasibility of the division and sum polarity method is validated in this study, which provides a new approach for eliminating stimulus artifacts when measuring evoked potentials.

The general acidification technology of horizontal wells provides a simple and important method of stimulation for carbonate gas reservoirs. The common acidization methods were divided into two major categories: matrix acidification and fracturing acidification. To determine the best stimulation method of horizontal wells between acid fracturing and matrix acidizing, it is significant to achieve the efficient exploitation of reservoirs and optimization of process program. A dimensionless gas production index formula was obtained for horizontal well acidizing in carbonate gas reservoir. Also, a carbonate-acid-stimulation coefficient model was established to optimize the general method of acidification for the horizontal wells in carbonate gas reservoirs. Then, the influence of geological and engineering factors on the acidization increase coefficient was analyzed. Finally, field verification and application were conducted. The conclusions are as follows. When the carbonate-acid-stimulation coefficient R_JH>1, the productivity of matrix acidizing wells exceeds that of fractured acidizing wells. When R_JH<1, the productivity of fractured acidizing wells is higher compared to matrix acidizing wells. A higher permeability anisotropy coefficient increases, the number of fracturing fractures and the amount of acid fluid, but reduces the carbonate-acid-stimulation coefficient. The increase in porosity and horizontal length lead, to a higher carbonate-acid-stimulation coefficient. When the porosity of the gas reservoir falls below 7.3%, the productivity of the fractured acidizing well is improved. When the length of the horizontal section is 500 m and the number of fracturing fractures exceeds 4, the carbonate-acid-stimulation coefficient R_JH<1, and the productivity of the fractured acidizing well is improved. When the total volume of acid solution injected is 600 m³, the productivity of fractured acidizing well reaches a higher level than when the acid-solution volumetric dissolving power X>0.08.As verified in the carbonate reservoirs located in the northeastern Sichuan block, the production increase effect produced by using the carbonate-acid-stimulation coefficient method is significant after process optimization. Therefore, a theoretical guidance is provided in this paper for optimizing the acidification method of horizontal wells in carbonate gas reservoirs.

The Kezirto pluton is located in the alkaline intrusive rock belt on the northern margin of the Tarim Basin. The lithology is alkaline granite. The petrogeochemical characteristics were studied in detail. The U-Pb isotope age of the pluton was measured by LA-ICP-MS method, which provides a basis for the study of the characteristics, age, genesis and formation environment of the pluton. At the same time, the nature of late Paleozoic magmatic activities and their tectonic settings in the area were studied, which can better guide the exploration work in the area and have important theoretical and practical significance. The Kezirto granite pluton was divided into two parts, north and south. The total rare earth element content is relatively high. The ∑REE of the northern pluton was 261.723×10^-6~834.783×10^-6, and the ∑REE of the southern pluton is 422.174×10^-6~575.86×10^-6. HFSE(high field strength elements) are obviously enriched relative to LILE(large ion lithophile elements), and elements such as Ba, Sr, P, and Ti are obviously depleted, with obvious negative Eu anomalies. The chondrite-normalized rare earth element diagram shows a slightly right-inclined seagull-like shape, and light rare earth elements are slightly enriched compared to heavy rare earth elements. The Kezirto pluton is A1-type granite. The LA-ICP-MS U-Pb isotope ages of the north and south plutons are (273.8±2.9) Ma and (274.8±1.8) Ma, which are contemporaneous plutons. The formation of the Kezirto pluton is due to the underplating of mantle-derived magma, which leads to the remelting of ancient rocks in the lower crust. After that, it undergoes fractional crystallization. During the formation process, it is contaminated by the crust to different degrees. The pluton has experienced the tectonic environment of deep mantle plume and intracontinental rift.

A simplified lower-limb exoskeleton model was established for the prototype, and the D-H parameter method was used to perform dynamic analysis. Joint angles were measured experimentally and used as inputs for the controller. To address the robot's trajectory tracking problem, traditional PID control was employed, showing good tracking performance but slow response and parameter tuning speed. Although PSO(particle swarm optimization) accelerated the parameter tuning, issues with low convergence accuracy and local optimum traps persisted. Therefore, a PID control based on a chaotic-mapping improved PSO algorithm was designed. The results show that the randomness was enhanced, the parameter tuning speed was increased, and the tracking error was reduced. Simscape was used for visual simulation of joint angles, and the control performance was further validated through various experiments.

Exploring the impact of various hole shapes on the acoustic emission properties of rocks and the fracture mechanisms within rock structures containing holes is of utmost importance, as it enables the detection of fracture progression in rock engineering and the prediction of instability and failure in defective rocks. The mechanical properties, acoustic emission evolution patterns, precursor characteristics of failure, and failure mechanisms of red sandstone samples with different hole shapes were investigated through uniaxial compression tests and acoustic emission systems. The results indicate that the compressive strength, elastic modulus, and strain energy of the intact specimen are approximately 1.4 times, 1.3 times, and 1.7 times greater, respectively, than those of the specimen containing holes. There is a mutation point in the evolution of the multifractal spectrum of A_E at 86%~95% of the peak stress, where the width undergoes a transition from an average low value to a sudden increase before and after the mutation point. This change is accompanied by an increase in fluctuation range, from small to large. The A_E waveform characteristics are distinguished by the presence of dual main frequency bands. As the sample approaches failure, a significant number of low-frequency and high-amplitude signals, along with high-amplitude and high-amplitude signals, are generated. These peculiar trends in acoustic emission can be used as precursors to the critical instability of red sandstone. Based on the correlation between the main frequency of the acoustic emission signal of the rupture event and the fracture mechanism of the rock, the failure mechanism of the intact and square cavity red sandstone is mainly characterized by tension-shear mixed failure, and the shear failure of circular cavity red sandstone is revealed, which effectively avoids the subjectivity of the RA-AF failure mode classification method, and the research results can provide certain guiding significance for engineering design and optimization.

In order to understand the properties of char which is the main byproduct of coal pyrolysis in the reactor with internals, especially the char prepared at high temperatures, the char samples were prepared by pyrolysis of Yulin bituminous coal under vacuum condition between 1 000 ℃ and 1 500 ℃ in the fixed-bed reactor with internals. The variations of pore structure, composition, calorific value, and carbon structure of chars with pyrolysis temperature were studied. The isothermal combustion characteristic and kinetics were investigated by MFBRA(micro fluidized bed reaction analyzer). The results show that the increase in pyrolysis temperature leads to a deeper degree of pyrolysis. As the pyrolysis temperature increases, the C content and C/H molar ratio of chars gradually increase, H and O contents of chars gradually decreases, and the calorific value increases slightly. The specific surface area and pore volume of chars firstly decrease with the increase of pyrolysis temperature, and then remain essentially constant after the pyrolysis temperature exceeds 1 300 ℃, which is consistent with the trend of graphitization degree. The three-dimensional diffusion model G(x)=[1-(1-x)^1/2]² can well describe the combustion process of chars. The activation energy and pre-exponential factor increase with the increase of pyrolysis temperature, and vary in the range of 30.49~90.17 kJ/mol and 0.69~352.25 s^-1, respectively. The significant decrease in combustion reactivity of char prepared above 1400 ℃ is mainly due to the sharp increase of C/H.