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This study examines the future spatial distributions and long-term trends of the sea ice concentration (SIC) and the sea ice thickness (SIT) in the Arctic, along with the potential impacts of the Temperature at Surface (TAS), using the outputs of six models under four forcing scenarios of the Coupled Model Intercomparison Project Phase 6 (CMIP6). The results show that, under the four forcing scenarios, the SIC exceeds 50% and the SIT is approximately 1.5 m in most parts of the Arctic in 2030, 2040, and 2050. However, in the regions of East Greenland, the Barents Sea, the Kara Sea, and the Chukchi Sea, the SIC and SIT are comparatively lower and thinner. Both the SIC and the SIT exhibit declining trends during 2015—2050. Specifically, under the high-forcing scenario, the SIC in some regions decreases by over 1% per year. In 2050, under the high-forcing scenario, the SIC in most of the Arctic exceeds 90% during winter and spring months. The SIC reveals a decreasing trend in every month. The SIT exceeds 1 m from winter to summer in most regions, while it is less than or equal to 0.5 m in the fall. From December to May, the SIT exhibits a decreasing trend across the Arctic, with some localized increases observed in other months. Regarding the long-term trend up to 2100, the SIC and SIT in the Central Arctic, the East Greenland Sea, and the Chukchi Sea decrease over time, with the fastest reduction in the Central Arctic, meanwhile the TAS continues to rise in these three regions. Additionally, the spatial distribution and long-term trend between the TAS and the SIC are opposite, implying the possible impact of the TAS on the SIC. These findings provide valuable insights into the future sea ice in the Arctic under different forcing scenarios.

The minimum measured wind speed of the existing anemometer can not meet the requirements of precise wind measurement under the condition of low wind speed in mines. In order to solve this problem, based on the principle of ultrasonic time difference method wind speed measurement, a high-precision mine ultrasonic anemometer with low starting wind speed is designed. Two ultrasonic transmitting probes and two ultrasonic receiving probes are arranged alternately to form two ultrasonic propagation paths. The downwind and upwind propagation times of ultrasonic waves in a specific wind speed field are measured respectively, and the average wind speed between the transmitting probes and the receiving probes is solved by using the superposition effect of the propagation speed of ultrasonic waves in the air and the wind speed (the effect of temperature on the wind speed measurement can be ignored). In order to analyze the effect of ultrasonic probe direction on the accuracy and reliability of measurement, four different probe arrangement modes are used to carry out the experiment. The results show that the more serious the ultrasonic probe direction dislocation is, the larger the standard deviation and fluctuation range of wind speed. Therefore, the infrared orientation device is used to calibrate the installation position of the anemometer to reduce the measurement error caused by the ultrasonic probe direction dislocation. The moving average method is used to smooth the original wind speed waveform curve to eliminate random noise and improve the stability of output wind speed. By analyzing the factors affecting measurement precision, it is determined that the ultrasonic emission frequency is 40 kHz and the standby time is 100 ms. The theoretical calculation and experimental results show that the resolution of the anemometer is 0.01 m/s, the measurement error is ±0.1 m/s, and the starting wind speed is lower than 0.1 m/s, which can meet the precise wind measurement requirements of the mine roadway with low wind speed.

The existing mine wind speed sensor arrangement methods have problems as follows. The determined sensor branch cannot measure the wind speed accurately because the wind speed is smaller than the sensor start wind speed. Most of the methods need to be listed multiple matrices and the calculation is complicated. Moreover, the sensor positions selected by some methods are unreasonable. In order to achieve mine full coverage air volume monitoring without blind area, and to monitor the air volume variation in all roadways with the minimum number of wind speed sensors, the coverage of sensor branches is analyzed by using the directed path matrix, and the optimal arrangement of wind speed sensors based on the directed path matrix method is proposed. This method determines the unique directed path matrix based on the wind flow direction of the ventilation network diagram, determines the coverage of the branches, and selects the branch with the largest coverage to determine the position of the wind speed sensor. The results show that the optimal arrangement of wind speed sensors based on directed path matrix method can achieve mine full coverage air volume monitoring without blind area, and the number of sensors is less than or equal to the number of independent directed paths. Calculation analysis shows that when sensors are arranged according to this method, there is a measurement error of 6% in one sensor branch, the lowest impact on the ventilation network is 0.52, and the lowest impact on other branches is 0. Moreover, the calculation error decreases as the number of sensors increases. If the impact of sensor branch error on the ventilation network is controlled to be less than 1, more than 12 wind speed sensors should be arranged.

Gold-assisted exfoliation can fabricate centimeter- or larger-sized monolayers of van der Waals (vdW) semiconductors, which is desirable for their applications in electronic and optoelectronic devices. However, there is still a lack of control over the exfoliation processes and a limited understanding of the atomic-scale mechanisms. Here, we tune the MoS2-Au interface using controlled external pressure and reveal two atomic-scale prerequisites for successfully producing large-area monolayers of MoS2. The first is the formation of strong MoS2-Au interactions to anchor the top MoS2 monolayer to the Au surface. The second is the integrity of the covalent network of the monolayer, as the majority of the monolayer is non-anchored and relies on the covalent network to be exfoliated from the bulk MoS2. Applying pressure or using smoother Au films increases the MoS2-Au interaction, but may cause the covalent network of the MoS2 monolayer to break due to excessive lateral strain, resulting in nearly zero exfoliation yield. Scanning tunneling microscopy measurements of the MoS2 monolayer-covered Au show that even the smallest atomic-scale imperfections can disrupt the MoS2-Au interaction. These findings can be used to develop new strategies for fabricating vdW monolayers through metal-assisted exfoliation, such as in cases involving patterned or non-uniform surfaces. [ABSTRACT FROM AUTHOR]

A modified model consisting of a dynamic Lee model, volume of fluid model, and continuum surface force model is developed. The modified model investigates heat transfer characteristics of the vapor–liquid phase change process and details of the two-phase flow during operation of a two-phase closed thermosyphon. The mass transfer time relaxation parameters for the Lee phase change model are the most critical coefficients which determine the rate of the vapor–liquid phase change. A dynamic adjustment of the mass transfer time relaxation parameters for the Lee phase change model is realized based on the amount of mass transfer between the vapor and liquid phases and the values of the mass transfer time relaxation parameters become stabilized. The relative error between the modified model and experimental data for the temperature distribution is 5%, representing an acceptable agreement. Compared with the original model, the maximum thermal resistance errors in evaporation section and condensation section are reduced by 19.3% and 107.1%, respectively. These results indicate that the modified model can provide good corrections with high accuracy. [ABSTRACT FROM AUTHOR]