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[Objective] In order to explore the relationship between the windbreak direction and the prevailing wind erosion direction in the black soil region of Northeast China. [Methods] The basic characteristics of the windbreak in the study area were obtained by remote sensing interpretation and field survey, and the angle of intersection between the windbreak direction and the prevailing wind erosion direction, that is, the wind direction declination angle, was calculated and analyzed by combining the wind speed and wind direction data of 43 meteorological stations in the study area. [Results] The westerly wind in Mengdong black soil sub-region accounted for a large proportion, the wind direction was more concentrated, the prevailing wind erosion direction dominance was strong, the wind direction in the Songnen black soil sub-region was scattered, and the prevailing wind erosion direction dominance was weak. Average windbreak density Songnen black soil sub-area > Mengdong black soil sub-region; The windbreak direction accounted for the largest proportion in the Songnen black soil sub-area was the N-S trend windbreak direction, and there was no obvious regularity in the Mengdong black soil sub-region. In the study area, the proportion of wind declination angle 30° was 70.40%, and the wind protection effect was poor. [Conclusion] The direction of a large number of windbreak in the study area is oblique to the prevailing wind erosion direction, and the protective effect is poor. The results of this study have important reference value for understanding the density and trend of existing windbreak belts, and for further construction and transformation of windbreak.

In the case of sequential mining with single wing arrangement in coal mine working face, the drilling along the working face is easily affected by the support stress of adjacent working faces, leading to drilling failure. At present, research on borehole protection focuses on enhancing the strength of the borehole itself, without proposing solutions to the fundamental factors that affect borehole stability. In order to solve the above problems, a hydraulic fracturing weakening roof borehole protection technology has been proposed. By using hydraulic fracturing to weaken the roof, the peak mining support stress acting on adjacent coal working faces is reduced, and the transmission of high support stress to the surrounding coal bodies in the bedding boreholes is blocked. The entire process of screening is carried out in the bedding boreholes to ensure that the gas escaping from the coal body can enter the bedding boreholes. Numerical simulation is used to analyze the changes in vertical stress and plastic zone of the coal body around the borehole before and after hydraulic fracturing weakening the roof. The results show that by weakening the roof through hydraulic fracturing, the peak vertical stress of the coal body around the borehole decreases from 21.2 MPa to 9.1 MPa, and the plastic zone range of the coal body decreases from 19 m to 11 m. According to the numerical simulation results, hydraulic fracturing parameters are determined and tested on site. The results show that after using hydraulic fracturing weakening roof borehole protection technology, the average volume fraction of gas extraction from boreholes increases from 3.6% to 14.1%. The average mixed flow rate of gas extraction decreases from 1.28 m3/min to 0.464 m3/min. There is no occurrence of coal oxidation and CO production in a large area of bedding boreholes. Therefore, hydraulic fracturing weakening roof borehole protection technology can effectively avoid drilling failure and gas leakage, improve drilling and extraction efficiency, and ensure drilling and extraction safety.

The hydrodynamic performance of propeller is mostly studied in calm water, but the propeller working behind ship is often affected by waves. According to the literature, there is relatively little research on hydrodynamic performance of propeller in waves at present. In view of this, RANS solver based on OpenFOAM is used to calculate and analyze the influence of waves on the thrust and torque of propeller. The results show that time history curves of thrust and torque oscillate under the influence of waves. The disturbance of free surface and the oscillation amplitude of time history curves increase with the decrease of immersion depth and advance coefficient. Compared with the calm water condition, the average thrust and torque of propeller in waves are reduced when the immersion depth and advance coefficient are the same. The computational results are in good agreement with the experimental data.

Talent is one of the basic and strategic supports for building a modern socialist country in all aspects. Since the 1980s, the establishment of forensic medicine major and the cultivation of innovative talents in forensic medicine have become hot topics in higher education in forensic medicine. Over the past 43 years, the forensic medicine team of Shanxi Medical University has adhered to the joint education of public security and colleges, and made collaborative innovation, forming a training mode of “One Combination, Two Highlights, Three Combinations, Four in One” for innovative talents in forensic medicine. It has carried out “5+3/X” integrated reform, and formed a relatively complete talent training innovation mode and management system in teaching, scientific research, identification, major, discipline, team, platform and cultural construction. It has made a historic contribution to China’s higher forensic education, accumulated valuable experience for the construction of first-class major and first-class discipline of forensic medicine, and provided strong support for the construction of the national new forensic talent training system. The popularization of this training mode is conducive to the rapid and sustainable development of forensic science, and provides more excellent forensic talents for national building, regional social development and the discipline construction of forensic science.

【Objective】 Maintaining soil moisture at a rational level not only improves water use efficiency but also benefits crop growth and grain quality. Taking rice as an example, this paper presents an experimental study of the effect of soil moisture on growth and water consumption of the crop. 【Method】 The experiment was conducted in pots, with the variety “Yangliangyou 6” used as the model plant. The soil moisture was kept at >90% (CK), 75%~90% (W2), 60%~75% (W3) and 45%~60% (W4) of the field capacity, respectively. In each treatment, we measured the total water consumption and water consumption intensity, biomass, yield, water use efficiency, and water potential in the leaves of the rice. 【Result】 A decrease in soil water content reduced water consumption of the rice. Compared with CK, W2, W3 and W4 reduced total water consumption by 32.4%, 58.7% and 69.9%, respectively, and water consumption intensity by 32.4%, 61.5% and 73.5%, respectively. The water use efficiency of W2 was significantly higher than that in other treatments. Compared with W1, W2 increased water use efficiency by 24.5% but reduced grain yield and biomass by 13.2% and 12.4%, respectively. In contrast, W3 and W4 reduced water use efficiency by 36.0% and 74.7%, respectively, compared to W1. 【Conclusion】 Considering water use efficiency and crop growth, maintaining soil water content at 75%~90% of the field capacity is optimal for improving water use efficiency, reducing water consumption without scarifying rice yield. It can be used as an improved irrigation method for rice production in the studied area.

Aiming at the problem that the deployment of transmission paths in MANET(mobile ad hoc network) for SDN(software defined network) requires the controller to issue related flow entries for all nodes on the path,thereby causing that the transmission have to wait for a long-term period,a mechanism for quickly issuing forwarding rules,FDSR(fast-deployed-segment-routing),is proposed.The controller will issue data forwarding rules by adding labels corresponding to the forwarding path on the data packets in the way of segmented routing,and when dealing with the max stack depth problem,use label adhesion technology to divide the entire path into multiple label stacks by algorithm,sending to corresponding forwarding nodes that can quickly inte-ract with the controller node to reduce path configuration time.Experiments show that compared with the OpenFlow distribution method,FDSR in SD-MANET (software defined mobile ad hoc network) can reduce path deployment time and flow table overhead,and can effectively deal with the MSD problem of SR and improve the long path deployment speed of the controller.

The relative neutron flux density distribution is one of the essential physical parameters of the reactor. Measuring the relative neutron flux density distribution of the annular fuel zero-power reactor core has guiding significance for understanding the physical characteristics of the annular fuel core reactor and conducting safety analysis. In this paper, the γ activity of the gold foil at different positions on the outer surface of the fuel cell after irradiation was measured by foil activation method under polygonal loading of annular fuel core. The axial and radial relative neutron flux density distributions of fuel cell at different positions were obtained, and the measured values were compared with the values calculated by Monte Carlo theory. The results show that the maximum relative deviation between experimental measurement and theoretical calculation is within 12%. The measurement results of relative neutron flux density distribution are in line with the measure design expectations. The existing Monte Carlo analysis methods can better analyze the axial flux density distribution of the components in the reactor. This study provides essential data support for the engineering application of annular fuel.

The power communication system based on synchronous digital hierarchy(SDH) optical, transmission technology is an important component to ensure the safety and stability of power network. After, years of development, the network has been gradually mature, but it still has many problems, such as the weak, structure of the communication network, insufficient network transmission capacity, weak network access and network management. Therefore, it is necessary to do the research and take simulation for the power communication system based on SDH optical transmission technology. The paper builds up the simulation, platform of SDH network in power communication system based on the EXATA simulation tools. For SDH, device, we implemented functions including multiplexing, demultiplexing and digital cross-connection. And, the simulation analysis provides a great theoretical support for constructing equipment models and network, topology.

The related coverage performance,Doppler shift and service-supporting capability of the IGSO constellation was studied for the given area.The results show that,the constellation,which consists of two or three IGSO satellites,can achieve good coverage characteristics（the percent of time of one and more satellites coverage and average elevation an-gle）to the Chinese and nearby area with small Doppler shift.The link budget shows that,adopting IGSO can effectively solve the low elevation angle problem faced by GEO satellite,and similar performance,which can only be implemented by a very big GEO satellite,can be achieved by two or three relatively small IGSO satellites.So the solution of adopting IGSO to provide mobile satellite communication system is technically feasible.

A summary and review about some hot points in current satellite communications technology was given.Firstly,the associated concept and developments of broadband satellite communication were introduced,then the main technical issues that need to be solved was proposed,and examples of the typical application were given.Secondly,based on the introduction of current developments about mobile satellite communication,the characteristics and key technology were studied.Finally,the basic concept of space communication network was introduced,the network composition and individual function were given,and some new technology that need to be developed was analized.