Latest ArticlesMuscle dysfunction, as one of the common extrapulmonary manifestations of COPD (chronic obstructive pulmonary disease), limits the exercise capacity, cardiorespiratory health, and quality of life of COPD patients, leading to poor prognosis. PBMT (photobiomodulation therapy) an emerging adjunctive treatment for COPD-related muscle dysfunction, has been widely promoted and utilized in clinical practice. It positively affects muscle inflammation, alleviates muscle fatigue, improves muscle metabolism, enhances muscle endurance, and accelerates muscle healing. The comprehensive review of the rehabilitation mechanisms and current application status of PBMT (photobiomodulation therapy) in addressing COPD (chronic obstructive pulmonary disease)-related muscle dysfunction, both domestically and internationally, is conducted to offer insights and guidance for the application of PBMT in the rehabilitation treatment of COPD-related muscle dysfunction.
In order to deeply understand the spatio-temporal distribution patterns of forest fires and reduce the adverse effects of forest fires on the ecological environment and human activities, the key parameters and dynamics of multi-source satellite for fire point identification was established using data from 8 domestic and foreign meteorological satellites and based on the classic context method. The satellite monitoring buffer zone radius verification method was used to verify the authenticity of forest hot spots retrieved from multi-source satellites, and the real forest hot spot data during the fire prevention period in 2021—2022 were used to analyze the spatio-temporal characteristics of forest fires. The results show as follows. The accuracy of satellite fire spot monitoring is 84.42%, and the fire point classification accuracy is 89.90%. The established inversion method is reasonable and reliable. The spatial distribution of forest fires in Hunan is “more in the southwest and less in the northeast”. At the same time the high-incidence areas are mainly distributed in southern Hunan, and the second-highest-incidence area is western Hunan. In summary, the risk of forest fires during the autumn prevention period is much greater than that during the spring prevention period. During the extreme high temperature and drought in 2022, forest fires were mainly distributed in the southern Hunan region and the Hengshao Basin. From the perspective of process distribution, the distribution of forest fires can be divided into four stages. The number of forest fires in the first three stages showed a significant increase trend, and in the third stage, the number of forest fires increased significantly. Fire risk is the most serious. In the fourth stage, due to the dual impact of precipitation and the province's fire ban, the risk of forest hot spots was significantly reduced.
In order to study the effect of temperature on the shear strength of fully weathered mudstone with different saturations,fully weathered mudstone specimens from a typical seasonal frozen region were used as the object of study.The GDS dynamic triaxial test system and the GDS unsaturated test system were used to conduct indoor triaxial tests on specimens with different saturations to investigate the trends of the shear strength parameters of fully weathered mudstone in the seasonal frozen region under different temperatures and surrounding pressures, and to compare and analyse the shear strength parameters of the two different saturations of the fully weathered mudstone were compared and analysed. The results show that the fully weathered mudstone is strongly influenced by saturation and temperature.The cohesion of both soil samples increases with decreasing temperature, and the internal friction angle increases and then decreases. The cohesion of the unsaturated mudstone specimens is consistently greater than that of the saturated mudstone specimens when the temperature and test system conditions are consistent. Saturation has a low effect on the internal friction angle of the specimens, which peaks at -5 ℃ and 0 ℃for the two soil samples respectively.
An analysis was conducted on the circulating flow process of coolant in the cooling water jacket of motorcycle single cylinder engines, twin cylinder engines, and four cylinder engines. The analysis of coolant flow velocity and water jacket wall heat transfer coefficient were conducted. Based on the analysis of the circulating flow path of coolant, the optimization of the cooling water jacket structure was studied. The results show that the coolant flow rate on the exhaust side and nose bridge area of a single cylinder engine is relatively low, and there is a zero flow rate area in the nose bridge area. The distribution of coolant flow rate in the two cylinders of a twin cylinder engine is uneven, and the coolant flow rate in the middle area of the connection between the two cylinders is relatively low. There is also an issue of uneven coolant flow rate in each cylinder of a four cylinder engine. By analyzing the flow path of coolant circulation, the flow direction and function of the coolant on the water holes on each cylinder gasket are clarified. Based on the design criteria that require key cooling in high-temperature areas, the layout of the water holes on the cylinder gasket and the local flow area of the water jacket are optimized for three types of engine cooling water jackets. After optimization, the coolant flow rate in the high-temperature areas such as the exhaust side and nose bridge area of the three types of engine cooling water jackets reached the requirement of not less than 1.5 m/s, and the difference in coolant flow rate between each cylinder is reduced. Through engine thermal balance verification, the optimization of the cooling water jacket structure for three types of engines can effectively reduce the temperature of the cylinder head spark plug gasket and reduce the temperature difference between the spark plug gaskets of each cylinder, verifying the effectiveness of the water jacket structure optimization design.
To address the voltage fluctuations caused by the integration of renewable energy into the distribution network, a voltage coordinated control method based on MPC (model predictive control) was proposed to ensure safe operation. Aiming at the uncertainty of wind and photovoltaic output, the AP-K-Medoids clustering algorithm was proposed to generate and reduce output scenarios, and a model was established with the optimization objective of minimizing system network loss. Adopting multi time scale voltage control through the integration of on load voltage regulating transformers, capacitor banks, static reactive power compensators, wind solar reactive power output, and energy storage charging and discharging coordination. Long term scale optimization control solves the output of each device in the system through multi-step rolling optimization, with wind solar output and load demand prediction as the premise. On the basis of short-term and long-term rolling optimization, the increment of output is solved. The optimization control model is a non convex and nonlinear model, which utilizes a second-order cone programming model to solve nonlinear problems. Using an improved IEEE33 node distribution network system for case analysis, the research results demonstrate the feasibility of the proposed voltage optimization control strategy.
The enhancement of oil recovery by altering the salinity and ion composition of injected water has become a focal point of numerous studies. However, there is relatively less attention given to techniques combining surfactants with the quality injected water. To investigate the synergistic effects of different cations and surfactants on recovery efficiency, micro-scale displacement experiments were conducted to simulate the displacement process, along with experiments measuring interfacial tension and viscoelasticity modulus at the oil-water interface. Results from the micro-scale displacement experiments show that 10 000 mg/L NaCl solution and 50 000 mg/L CaCl2 solution exhibite the best oil recovery efficiencies, reaching 64.51% and 59.27% respectively. After adding surfactants, the efficiency improved further with 10 000 mg/L NaCl +0.2% dodecyl dimethyl ammonium betaine solution and 50 000 mg/L CaCl2+0.2% hexadecyl trimethyl ammonium bromide solution achieving the highest recovery rates at 87.28% and 80.92% respectively. Results from the interfacial tension and viscoelasticity modulus experiments indicated that when anionic and nonionic surfactants were added to NaCl and CaCl2 solutions, the interfacial tension reached the magnitude of 10-1 (m·N)/m. However, with the addition of amphoteric and cationic surfactants, the interfacial tension decreased to the magnitude of 10-2~10-3 (m·N)/m, accompanied by a significant decrease in viscoelasticity modulus. This study explores the mechanisms of the synergistic effects of different cations and surfactants on the displacement process, considering factors such as interfacial tension, viscoelasticity modulus, and wettability, and microscale oil displacement behaviors thus providing a comprehensive analysis of the relationship between multiple factors and recovery efficiency.
Radiation dose monitoring using thermoluminescent detectors is currently one of the main methods of personal or environmental dose monitoring in China. In order to solve the problem of uniformity screening before the use of thermoluminescent detector, and the complexity of the measurement process. Test dose and thermoluminescent peak counts normalization were used to optimize the measurement process of thermoluminescent detectors. With the simple irradiation device, the same batch of thermoluminescent dosemeters for radiation environment monitoring were measured using the optimized and general measurement processes. The relative error of the dose values of the two was within ±5%, which satisfied the accuracy requirements of thermoluminescent dosemeters in the process of monitoring the dose of ionizing radiation to the individual or the environment. The results show that the optimized thermoluminescent dosimetry process reduces detector uniformity performance requirements and improves the applicability of the process. It provides a high-precision, high-efficiency and low-cost measurement method for personal or environmental dose monitoring in China.
The sedimentary environment of Cardium formation in western Canada basin is the shallow sea coastal face. The conventional oil and gas reservoir was formed from the conglomerate and sandstone deposited on the coastal muddy seafloor. The unconventional tight oil reservoir was formed from the low-permeable argillaceous sandstone around the conglomerate. Faced with the coexistence of different types of resources, the development of SINOPEC oversea blocks with benefit needs to be realized. Firstly, the member A of Cardium formation was divided into three types according to the core observation and experiment test. Then the development features of different types of reservoirs were compared based on the production dynamic data. Thirdly, the geological knowledge was verified via single well theoretical models. Finally, the development potential of different types of reservoirs in the interest block were evaluated. The development strategies of different types of reservoirs were put forward. The results show that the member A of Cardium formation can be classified into type I conglomerate reservoir, type Ⅱ conglomerate reservoir and type III tight sandstone reservoir according to the lithology differences. From type I to type Ⅲ, the reservoir physical properties gradually weaken. The development way changes from vertical well development to multistage fracturing horizontal well development. The productivity controlling factors gradually complicates. Currently, type I and II reservoir in the interest block have a limited potential, which can be further released through reperforations on some old wells. Type III reservoir has a certain potential, which can be effectively released through deployment of large numbers of horizontal wells.
Acoustic wave is one of the important means to realize the fast and accurate transmission of downhole information. The drill string serving as information transmission channel has obvious periodic pipe structure characteristics. In order to study the frequency spectrum quality of drill string channel in actual working conditions, a multilevel evaluation method of acoustic frequency spectrum based on improved radar chart was provided. The influence of axial tension stress on the frequency spectrum characteristics of acoustic wave in pipe structure was studied and analyzed by the method, and the criteria for judging the frequency spectrum characteristics were established. Practice shows that, the existence of tensile stress has a significant impact on the acoustic frequency spectrum and passband characteristics. With the increase of tensile stress, the evaluation index of frequency spectrum characteristic increases first and then decreases, and there exists a peak point with the best frequency spectrum characteristic. This method can comprehensively reflect the influence of different factors on the frequency spectrum characteristics of acoustic wave in drill string channel, and comprehensively evaluate the distortion degree of frequency spectrum characteristics from the multiple perspectives. It provides a basis for optimizing carrier frequency and designing the installation position of repeater when dealing with multi-factors interference in the field application of downhole information acoustic transmission technology.
To address the bottleneck issues in vehicle access efficiency for horizontal shifting mechanical parking garages, an access vehicle scheduling optimization model based on the PSO-OBL algorithm was proposed. The model aims to shorten vehicle access operation time and reduce user average waiting time by precisely controlling vehicle access strategies and time management. To enhance the optimization performance and convergence rate of the traditional particle swarm optimization algorithm, an innovative approach incorporating inter-particle collaboration and information exchange mechanisms was embedded into the algorithm framework, along with the integration of an opposition-based learning mechanism for efficient problem-solving. Experimental data indicates that, compared to the traditional particle swarm optimization algorithm, the PSO-OBL algorithm achieves significant improvements in customer average waiting time, average service time, average queue length, and average energy consumption. The findings of this study are expected to provide theoretical support and practical reference for optimizing access efficiency in horizontal shifting mechanical parking garages.