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【Background and Objective】 The arid and semi-arid regions in Northwest Liaoning Province are characterized by low precipitation and high evaporation, leading to desertification, soil erosion and degradation. This paper presents the results of an experimental study on variation and determinants of saturated hydraulic conductivity of soils in these regions. 【Method】 This study was conducted in grasslands exhibiting various levels of desertification. We measured the saturated hydraulic conductivity of soils at different depths, along with various influencing factors across different regions. 【Result】 The impact of desertification on soil hydraulic conductivity varied with soil depth. In the top 0-30 cm soil, the saturated hydraulic conductivity of soil in non-deserted, slightly deserted, moderately deserted, and severely deserted regions was 2.46 mm/min, 5.57 mm/min, 8.72 mm/min and 9.04 mm/min, respectively. The impact of desertification on hydraulic conductivity of soil in the 30-70 cm layer is similar, with the saturated soil hydraulic conductivity in the non-deserted regions being 30% of that in the severely deserted region. In the 70-100 cm layer, the saturated soil hydraulic conductivity in different regions was ranked in the order of non-deserted < slightly deserted < severely deserted < moderately deserted, with the saturated soil hydraulic conductivity in the non-deserted region being 40% of that in the moderately deserted region. Saturated soil hydraulic conductivity was negatively correlated with soil phosphatase and positively correlated with sand content, bulk density, and porosity of non-capillary pores. Soil saturated hydraulic conductivity linearly decreases with soil desertification in y=13.13x-31.80, which could explain 98.70% of the variation in the hydraulic conductivity. It was also found that, regardless of the level of desertification, soil hydraulic conductivity tended to increase with soil depth and vegetation coverage. 【Conclusions】 The saturated hydraulic conductivity of soils in the grasslands in the northern Liaoning Province varies with both soil depth and the degree of desertification. Key factors influencing this variation include sand content, phosphatase content, bulk soil density, and presence of large non-capillary pores.

【Objective】 Restoring coal mining waste dumps is a way to alleviate their detrimental impact on environment. In this paper, we present the results of an experimental study on distribution and stability of soil aggregates in a reclaimed coal mining overburden dump. 【Method】 The experiment was carried out at a reclaimed coal mine dump site in a grassland region in northern China. We measured the development of fissures from Zone I (GF) to Zone three (GFIII) in the fissure zone. The composition and distribution soil aggregates in these zones were determined using dry-wet sieve method. Aggregate stability and its relationship with the fissures was analyzed. 【Result】 The content of the >0.25 mm air-dried aggregates over the fissure zones was 23.02%~42.70%, and content of the >0.25 mm water-stable soil aggregates was 16.9%~29.52%. There was no significant difference between air-dried aggregates and water-stable aggregates. The content of the >0.25 mm water-stable soil aggregates in the 0~60 cm soil layer in GF, GFⅡ and GF Ⅲ was 25.26%, 26.57%, 23.62%, respectively, while the percentage of aggregate destruction in the three fissure zones was 20.77%~36.17%, 20.52%~25.00%, and 26.58%~40.56%, respectively. The percentage of aggregate destruction in 0~10, 10~20, 20~30, 30~40, 40~50, and 50~60 cm soil layers was 28.81%, 29.96%, 26.19%, 23.50%, 24.91%, and 29.38%, respectively. The fractal dimension of air-dried and water-stable soil aggregates was 2.847~2.919 and 2.898~2.942, respectively. Small aggregates and fine particles are the dominant aggregates. The mean mass diameter (MWD) and geometric mean diameter (GMD) of the air-dried aggregates in three fissure zones were 1.11, 1.05, 1.28 mm, and 0.45, 0.44, 0.49 mm, respectively. The MWD and GMD of water-stable soil aggregates in the three fissure zones were 0.67, 0.73, 0.72 mm, and 0.36, 0.38, 0.37 mm, respectively. Soil in GFⅡ had good structure and aggregate stability. Most of water-stable soil aggregates in the fissure zones were unstable due to the formation and development of fissures. 【Conclusion】 The formation and development of fissures in the reclaimed coal mining overburden dump reduced the stability of soil aggregates, thereby resulting in aggregate segmentation. The larger and wider the fissures were, the less stable the soil aggregates were.

This study describes a rare case of male granulomatous lobular mastitis (GLM) with recurrence in different sites on the ipsilateral side. A 48-year-old male patient presented with no previous history of breast-related disease, and physical examination suggested a mass in the right breast. Ultrasonography revealed a cyst and infection in the right breast. No obvious abnormality was found in laboratory analysis, and a core needle biopsy revealed GLM. Incision and drainage were applied to the right lesion, and symptoms resolved within a few weeks. At 2 years following this initial presentation, the patient reported that the right breast mass reappeared in different locations after the consumption of alcohol. Relevant examination and a core needle biopsy again suggested GLM of the right breast. The patient declined hormone therapy and was subsequently lost to follow-up. After reviewing this case, the course of the disease in this patient, and the connection between gynecomastia and GLM, along with ipsilateral recurrence, are under investigation.

To effectively monitor and control the severe mining-induced rockburst in deep fault area, the fault activation law and the mechanical essence of rockburst induced by crossing fault mining were studied through theoretical analysis, microseismic monitoring, field investigation, and other methods; numerical simulation was employed to verify the obtained fault activation law and the mechanical nature. First, the distribution of microseismic sources at different mining locations and the fault activation degree were analyzed. According to the microseismic frequency and the characteristics of the energy stage, the fault activation degree was divided into three stages: fault stress transfer, fault pillar stress behavior, and fault structure activation. It was determined that the impact disaster risk was the strongest in the stage of the fault pillar stress behavior. Based on the periodic appearance law of microseisms in fault area, three types of conceptual models of fault-type rockburst were proposed, and the rockburst carrier system model of “roof-coal seam-floor” in the fault area was established. The mechanical essence of fault-type rockburst was obtained as follows: under the action of fault structure, the static load of the fault coal pillar was increased and superimposed with the active dynamic load of the fault, leading to high-strength impact disaster. Finally, the prevention and treatment concepts of fault-type rockburst were proposed. The monitoring and prevention measures of fault-type rockburst were taken from two aspects: the monitoring and characterization of fault rockburst and weakening control of the high static load of the fault coal pillar and dynamic load of fault activation. The proposed concepts and technical measures have been verified in the working face 14310 of Dongtan Coal Mine with sound results. The research results have a guiding significance for the prevention and control of rockburst in a similar mining face under crossing fault mining.

Background: Acetabular roof was a crucial structure for maintaining the stability of hip joint; however, its important role was not especially emphasized in the Letournel-Judet classification system. Acetabular roof was segmented into the roof column and roof wall in Three-column classification and fracture in this area alone was defined as A3 injury. The purpose of this study was to explore the characteristics and surgical strategy of A3 injury. Methods: Patients with roof column/wall fractures received surgical management from January 2015 to 2019 January at nine level-1 trauma centers were retrospectively analyzed. Fracture data, surgical incision, operation time, blood loss, fracture healing and relevant complications were recorded to explore fracture characteristics and appropriate surgical strategy. Reduction quality was assessed based on postoperative radiographic examination. Merle d'Aubigné score was used to assess the functional outcome during the follow-up. Results: A total of 60 patients met the inclusion criteria in this study. Mean operation time was 112.83±21.77 min, and mean intraoperative blood loss was 396.67±182.00 ml. Satisfactory reduction quality was obtained in 49 cases (81.67%). All fractures healed well at an average mean of 3.07 months. Satisfactory outcomes were obtained in 46 cases (76.67%), and mean Merle d'Aubigné score was 15.53±1.33 points at the final follow-up. Reduction quality and functional outcome showed no statistical difference in three subtypes (P<0.05). Reduction quality and functional outcome presented positive correlation in three subtype fractures (P<0.05). The complication rate was 11.67% (7/60) in this study. Conclusion: The injury mechanism of A3 injury was the direct impaction from femoral head on acetabular roof. Reduction and fixation of A3 injury were technique demanding, and poor prognosis may be accompanied even treated by experienced surgeons. Appropriate surgical strategies (Table 5) based on fracture characteristics in three subtypes of A3 injury were the premise of accepted prognosis. [ABSTRACT FROM AUTHOR]

The influence of carrier mobility on the space charge transport behavior inside the oil-impregnated pressboard insulation of converter transformers cannot be neglected. However, at present, current knowledge is usually derived from empirical or theoretical values, lacks experimental studies, and often ignores the effects of temperature and field strength under actual operating conditions. In this paper, based on the variable-temperature surface potential decay (SPD) method, a carrier mobility measurement platform for oil-impregnated pressboard is established, and the carrier mobility values for different combinations of oil and oil-impregnated pressboard are obtained experimentally to analyze and reveal the influence mechanisms of temperature and field strength on the carrier mobility. The results indicate the following: (1) The positive and negative carrier mobilities of oil-impregnated pressboard are in the range of 10−12–10−13 m2·V−1·s−1, and the negative carrier mobility is always higher than the positive carrier mobility. (2) The carrier mobility is positively correlated with the changes of temperature and field strength, and when the temperature increases from 20 °C to 80 °C, the positive and negative carrier mobilities increase by 4.01 times and 4.72 times, respectively; when the field strength increases from 1 kV/mm to 7 kV/mm, the positive and negative carrier mobility increases by 2.53 and 2.72 times, respectively. (3) The carrier mobility of the pressboard with a higher oil absorption rate changes more significantly with temperature; when the field strength is 7 kV/mm and the temperature increases from 20 °C to 80 °C, the positive polarity carrier mobility increases from 3.96 × 10−13 m2·V−1·s−1 to 2.64 × 10−11 m2·V−1·s−1, an increase of 66.67 times, while the increase in the carrier mobility of the pressboard with a lower oil absorption rate is only 1.59 times. (4) The carrier mobility of the naphthenic transformer oil-impregnated pressboard is higher than that of the paraffin-based transformer oil-impregnated pressboard, and the carrier mobility of two kinds of naphthenic transformer oil-impregnated pressboard is 3.16 times and 2.47 times higher than that of the paraffin-based transformer oil-impregnated pressboard, respectively, under the conditions of 60 °C and 7 kV/mm. (5) Utilizing the Darcy model and microscopic scanning results of the pressboard morphology, it was revealed that permeability and fiber structure are key factors influencing the variation in carrier mobility. The research results of this paper can provide theoretical basis for the calibration and optimization of the oil-pressboard insulation structure of converter transformers. [ABSTRACT FROM AUTHOR]

SiC MOSFETs have been a game-changer in the domain of power electronics, thanks to their exceptional electrical traits. They are endowed with a high breakdown voltage, reduced on-resistance, and superior thermal conductivity, which make them supremely suitable for high-power and resilient applications across aviation, automotive, and renewable energy sectors. Despite their intrinsic advantages, SiC MOSFETs also necessitate advanced safeguarding mechanisms to counteract the vulnerability to short-circuit conditions due to their lower short-circuit robustness. This review paper offers an in-depth analysis of the array of short-circuit protection (SCP) methods applied to SiC MOSFETs. This paper scrutinizes techniques such as desaturation detection, di/dt detection, gate charge characteristics monitoring, two-dimensional monitoring, Rogowski coil-based detection, and two-stage turn-off strategies. The paper meticulously explores the operational principles, merits, and limitations of each method, with an emphasis on their adaptability to various fault types, including hard switching faults and load-induced faults. This review acts as a thorough compendium, guiding the choice of pertinent SCP strategies, ensuring the secure and efficient functioning of SiC MOSFETs in demanding applications. [ABSTRACT FROM AUTHOR]

In the past, the construction of high-speed railway stations was mostly concentrated in cities, rarely in cultural reserve area, and the degree of humanistic environmental protection was low. In addition, most of the high-speed railways entered into the city with ground lines, which had adverse effects on the urban environment. In this paper, the advantages and disadvantages of the current high-speed railway station construction concepts at home and abroad were analyzed. The design concept and method of the new generation of high-speed railway station and tunnel projects, included environmental integration, safety and comfort, low-carbon environmental protection, etc., were proposed based on the Beijing-Zhangjiakou High-speed Railway station and tunnel projects, especially Tsinghua Park shield tunnel with the theme of intelligent construction and underground Badaling Great Wall Station with the theme of cultural protection. Environmental integration includes station scene integration in scenic spots and tunnel-city integration in high-speed railway processes; safety and comfort concept include the safety of the station and tunnel engineering structure and the comfort of the operating environment; Low-carbon environmental protection includes BIM-based environmental protection and efficient whole-process management concepts, as well as green and low-carbon construction and operation concepts. [ABSTRACT FROM AUTHOR]