Search

To evaluate the crack sensitivity of Q350EW high-chromium weathering resistant steel during continuous cast⁃ ing， the high-temperature thermoplastic characteristics of Q350EW high-chromium weathering resistant steel were studied using Gleeble3500 thermal simulation testing machine， and the distribution of precipitates in the steel was calculated us⁃ ing Thermo-Calc thermodynamic software. Scanning electron microscopy and optical microscopy were used to observe and analyze the macrostructure and microstructure morphology of high-temperature tensile fractures and microstructure at the fractures. The research results indicate that as the heating temperature increases， the tensile strength of the test steel de⁃ creases； The cross-sectional shrinkage curve shows a concave valley around 700 ℃-800 ℃， with the lowest cross-sectional shrinkage of 64. 9% at 775 ℃. The fracture morphology within the range of concave valley temperature is mainly composed of ductile dimples， and its fracture mechanism is ductile fracture. Microscopic analysis shows that ferrite appears at the grain boundaries of the original austenite， leading to a decrease in plasticity. However， due to the high content of ferrite， the plasticity of Q350EW high chromium weather resistant steel still remains at a high level. By optimizing key process pa⁃ rameters such as secondary cooling during continuous casting， the risk of cracking in Q350EW high chromium weather re⁃ sistant steel billets can be reduced. It is recommended that the temperature of the corner bending and straightening section of the billets be less than 750 ℃.

In this study, the effects of applying a full oxygen blast furnace (FOBF) on carbon emissions were investigated by determining the ultimate minimum carbon consumption and a carbon metabolism calculation model. The results demonstrate that the minimum coke ratio of the top gas circulation-FOBF (TGR-FOBF) is significantly reduced (from 270 to 207 kg·thm−1) compared to that of the traditional ironmaking blast furnace (TBF). Owing to the complete recycling of the furnace top gas of the TGR-FOBF, the degree of direct reduction of TGR-FOBF significantly decreased to 0.14. The replacement of the TGR-FOBF with the three TBFs significantly reduced the CO2 emissions, which were the highest at 1.761 t-CO2/t-CS. Most of the CO2 emissions were generated by the direct combustion emissions (CDE) and direct process emissions (PDE), with a small amount generated by the electricity indirect emissions (EIE). The CO2 emissions generated by CDE, PDE, and EIE were 0.872 t-CO2/t-CS, 0.840 t-CO2/t-CS, and 0.049 t-CO2/t-CS, respectively. As the amount of TGR-FOBF replaced with the three TBFs increased, the CO2 emissions generated by the CDE and PDE significantly decreased. When all three TBFs were replaced with TGR–FOBF, the CO2 emissions generated by the CDE and PDE decreased to extremely low levels of 0.267 t-CO2/t-CS and 0.065 t-CO2/t-CS, respectively.

Network slicing is an important technology in 5G networks. The existing research on mine 5G mainly focuses on system architecture and application scenarios, lacking specific implementation solutions for slicing technology. In order to solve the above problem, by analyzing the basic structure of mine 5G networks and the application requirements of intelligent mines, it is proposed to use the channelization function of FlexE to achieve resource allocation and business isolation in the transmission network. It constructs multiple on-demand customized dedicated logical networks on the same network infrastructure, namely network slicing. According to the current applications of mine information communication systems and intelligent mines, a method of mine 5G network basic slicing+transmission resource allocation based on bandwidth weight is proposed. The network is divided into five types of slicing: low delay service, large bandwidth service, industrial ring network service, specific service (unmanned cooperative control) and reserved service. Through further virtual private network (VPN) division method, differentiated bandwidth weight is designed to ensure sufficient transmission resources and avoid channel congestion. The specific 5G QoS identifiers (5QI) are defined based on the requirements of different services for latency and bandwidth. The mapping and isolation based on 5QI are obtained to provide the required service levels for various businesses. Under laboratory conditions, two indicators of business scheduling time and end-to-end delay are tested for mine 5G network systems. The results show that network slicing can achieve more efficient business scheduling than traditional best-effort service models. In high-load scenarios, the average scheduling time is reduced by 10.9%. Within the same business slice, the average end-to-end delay of the mine 5G network is 10.33 ms, providing necessary conditions for the implementation of unmanned collaborative control and other services.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cow milk is rich in proteins, fats, carbohydrates, and minerals; however, its precise nutrient content varies based on various factors. In the current study, we evaluated the differences in the fatty acid and protein contents of milk and the factors associated with these differences. To achieve this, samples were collected from seven types of cows in different regions. These included samples from three dairy breeds: Chinese Holstein milk from Beijing, China (BH), Chinese Holstein milk (HH) and Jersey milk (JS) from Hebei province, China; and four dairy/meat breeds: Sanhe milk (SH) from Inner Mongolia Autonomous Region, China, Xinjiang brown milk (XH) and Simmental milk (SI) from Xinjiang Uygur Autonomous Region, China, and Shu Xuanhua milk (SX) from Sichuan province, China. Breed significantly affects total fat, fatty acid, and protein contents. Additionally, geographic region significantly affects the contents of different fatty acids, α-lactalbumin, and lactoferrin. JS has the highest total fat and casein contents. XH samples contain significantly higher unsaturated fatty acid content than BH samples and do not differ significantly from JS. Additionally, the low β-lactoglobulin and high lactoferrin contents in XH samples may be favorable for the growth and development of infants. Our results may inform the development of dairy products from different cow breeds and advance the process of accurate breed identification. [ABSTRACT FROM AUTHOR]

MicroRNA-mediated post-transcriptional regulation plays key roles in stem cell self-renewal and tumorigenesis. However, the in vivo functions of specific microRNAs in controlling mammary stem cell (MaSC) activity and breast cancer formation remain poorly understood. Here we show that miR-31 is highly expressed in MaSC-enriched mammary basal cell population and in mammary tumors, and is regulated by NF-κB signaling. We demonstrate that miR-31 promotes mammary epithelial proliferation and MaSC expansion at the expense of differentiation in vivo. Loss of miR-31 compromises mammary tumor growth, reduces the number of cancer stem cells, as well as decreases tumor-initiating ability and metastasis to the lung, supporting its pro-oncogenic function. MiR-31 modulates multiple signaling pathways, including Prlr/Stat5, TGFβ and Wnt/β-catenin. Particularly, it activates Wnt/β-catenin signaling by directly targeting Wnt antagonists, including Dkk1. Importantly, Dkk1 overexpression partially rescues miR31-induced mammary defects. Together, these findings identify miR-31 as the key regulator of MaSC activity and breast tumorigenesis.

In view of problems of co-channel interference emerged in wireless communication in coal mine emergency rescue based on Bluetooth transmission, the paper proposes a method of realizing anti-interference using frequency hopping technology. Mine-used vital sign parameter sensors connect with mine-used data acquisition terminals via Bluetooth signals. When the state of the channel is occupied, a vital sign parameter sensor changes the channels through the way of frequency hopping technology controlled by a data acquisition terminal, which searches in progressive increase for unoccupied channels in order according to the table of Bluetooth channel states and transforms the state of these changed channels into the occupied state. The underground test results indicate that this method can distribute terminals to different channels effectively and avoid the situation of co-channel interference at the same time, which enhances the stability of underground emergency communication system and the capability of emergency rescue.

Through comparing and analyzing network deployment of 5G non-standalone (NSA) and standalone (SA) as well as their advantages and disadvantages, and combining with current status of 4G 'one network one base-station' generally applied in coal mine underground, a 4G-5G fusion network architecture of coal mine underground based on NSA is proposed which uses 4G network to realize voice and dispatch functions and 5G network to expand other intelligent applications, so as to minimize investment. 5G network transmission modes in coal mine underground are researched, and three front-haul transmission networking schemes of 5G hosted network are focused on as well as their applicable scenes: Fibre-optical direct-connection scheme is applicable for scenes including robot inspection in underground pump house, substation and other places, virtual reality(VR)/augmented reality(AR) training, unattended working face; Passive wavelength division multiplexing scheme is applicable for underground scenes with simple network deployment and high independent maintainability; Active optical transport network scheme is applicable for different scenes flexibly. Four application scenes of 5G network slice in coal mine underground are probed on, which are intelligent inspection robot, environment monitoring and security protection, VR/AR smart coal mine and driverless vehicle, and application modes of 5G networking architecture in different scenes are analyzed.

The microstructural characteristics and mechanical properties of the simulated coarse grained heat affected zone (CGHAZ) in high N V-alloyed steel have been conducted under different welding heat input, characterized by the cooling time taken from 800°C to 500°C (t8/5). The experimental results show that the microstructure is dominantly composed of lath bainite (LB) and granular bainite (GB) at t8/5 30 s– 90 s. The content of LB decreases with t8/5 increasing, and that of GB increases. When t8/5 further increases to 120 s and 180 s, the microstructure mainly consists of intragranular polygonal ferrite (IPF) and acicular ferrite (IAF). The higher t8/5 leads to the increased content of intragranular ferrite (IGF). Meanwhile, the prior austenite grain size (PAGS) progressively increases from 56 ± 6.0 μm to 148 ± 9.9 μm as t8/5 increases from 30 s to 180 s. Besides, EBSD analysis indicates that the fraction of high angle grain boundaries (HAGBs) is 0.570, 0.427 and 0.624, respectively, corresponding to t8/5 30, 90 and 180 s. Moreover, the impact toughness decreases as t8/5 increases from 30 s to 90 s caused by the increased PAGS and GB content, and then sharply increases with t8/5 exceeding 90 s due to the increased formation of IGF, especially IAF. Furthermore, the high nitrogen content accelerates V(C,N) precipitation, which not only inhibits the coarsening of prior austenite grains, but promotes the formation of IGF, resulting in the increased number of HAGBs and raising impact toughness.

In a recent communication (Angew. Chem. Int. Ed. 2024, 63, e202317312), Kalita et al. studied In4H+ system within the frame of single‐reference approximation (SRA) and found that the global energy minimum (1 a) adopted the singlet state and a planar tetracoordinate hydrogen (ptH), while the second lowest isomer (1 b) located 3.0 kcal/mol above 1 a and adopted the triplet state as well as non‐planar structure with a quasi‐ptH. They assessed the reliability of SRA by checking the T1‐diagnostic values of coupled cluster calculations. However, according to our multi‐configurational second‐order perturbation theory calculations at the CASPT2(12,13)/aug‐cc‐pVQZ (aug‐cc‐pVQZ‐PP for In) level, both 1 a and 1 b exhibit obvious multi‐referential characters, as reflected by their largest reference coefficients of 0.928 (86.1 %) and 0.938 (88.0 %), respectively. Moreover, 1 b is 5.05 kcal/mol lower than 1 a at this level, that is, what can be observed in In4H+ system is the quasi‐ptH. [ABSTRACT FROM AUTHOR]

For problems that information security protection measures of industrial Internet of coal mine were mostly applied to small areas and it was difficult to assess the whole information security risk, an information security risk assessment method of industrial Internet of coal mine was proposed which was based on static and dynamic dimensions. In the method, security protection regulations carried out in coal mine information systems are feature-transformed according to Information Security Technology-baseline for Classified Protection of Cybersecurity and GB/T 34679-2017 General Technical Specifications for Smart Mine Information Systems, and a correlation coefficient matrix of security protection requirements for each system is established, so as to calculate the number of security protection regulations which are actually carried out in the system. Then, a security risk assessment model is established by combining with risk number and probability of higher risk category, so as to assess information security risk of industrial Internet of coal mine. The test result shows that the method can effectively assess information security status of industrial Internet of coal mine, and guide coal mine enterprise to analyze information security risk and design and carry out security protection plan, so as to decrease information security risk of industrial Internet of coal mine.

For low localization precision of existing underground personnel localization technologies, an underground joint localization method based on electromagnetic wave and ultrasonic was proposed by analyzing ranging principle of electromagnetic wave and ultrasonic wave as well as application characteristics in underground tunnels. In the method, a ratio of distance between a mobile node and two anchor nodes is obtained by approximate calculation according to logarithmic normal distribution model. Vertical coordinate of the mobile node is obtained by electromagnetic wave ranging method, and horizontal coordinate is gotten by ultrasonic wave ranging method. The Matlab simulation result verifies feasibility and localization precision of the method.