COSPAS-SArSAT has currently completed the design of a new generation distress beacon systems, namely the second-generation distress beacon system. The second-generation distress beacon adopts dSSS-OQPSK as its basic s...
COSPAS-SArSAT has currently completed the design of a new generation distress beacon systems, namely the second-generation distress beacon system. The second-generation distress beacon adopts dSSS-OQPSK as its basic signal modulation mode, while adopting a new signal detail structure. This paper provides a solution for the hardware implementation of the second-generation COSPAS-SArSAT distress beacon on Software-definedradio (Sdr). Firstly, the baseband signal that meets the definition format of the second-generation beacon standard was generated, and then the second-generation beacon was transmitted through the Universal Software radio Peripheral (USrP). By comparing with specific requirements of the second-generation distress beacon standard, the second-generation beacon generated by this paper can meet the requirements of the second-generation COSPAS-SArSAT distress beacon standard, and the method proposed in this paper has the advantages of flexibility and higher signal reconfigurability.
In this paper, a novel hybrid multi-criteria decision-making (MCdM) methodology called the CrITIC-MABAC approach is introduced. It is applied in optimization of laserdrilling of kenaf/high-density polyethylene (HdPE)...
详细信息
Autonomous underwater vehicles (AUVs) are efficient robotic tools, offering a wide range of applications in ocean exploration andresearch, such as oceanographic mapping, environmental monitoring, and archaeology. Inc...
详细信息
Micromilling is a subtractive manufacturing process that presents challenges due to scale effects andrapid tool wear. To understand the evolution of surface quality when increasing the machined length during the micr...
详细信息
Micromilling is a subtractive manufacturing process that presents challenges due to scale effects andrapid tool wear. To understand the evolution of surface quality when increasing the machined length during the micromilling process, this study assessed the surface roughness, topography, anddefects of slots micromilled on Ti-6A1-4V. For the experiments, 1 mm diameter flat end mills were employed, and the cutting parameters were varied using a full factorial design. Subsequently, the surface texture field parameter S a was assessed every 20 mm, up until the machining length of 260 mm. The analysedresults led to the conclusion that, for the adopted set of parameters and the machining length of up to 260 mm, surface roughness was not significantly correlated to the machined length in the micromilling process of Ti-6A1-4V, as the Pearson coefficient, obtained from the correlation analysis, was -0.052. However, the surface roughness was mainly influenced by feedrate (Pearson coefficient of 0.82), with higher feedrates leading to roug surfaces (up to S a = 0.4 µm) duhere to the tool load increase that causes wider feed marks on the surface. regarding the feed marks, they were affected by the tool rotational frequency due to system vibration. Additionally, surface defects of adheredmaterial, smearing, tearing and side flow were observed. For lower feeds, material adhesion was the main type of defect observed, while higher feedrates favoured the side flow phenomenon.
The Ediacaran-Cambrian (E-C) transition represents a crucial interval in Earth's history， with profound biological and environmental changes. Microbialites provide crucial records of organism–environment interac...
详细信息
The Ediacaran-Cambrian (E-C) transition represents a crucial interval in Earth's history， with profound biological and environmental changes. Microbialites provide crucial records of organism–environment interactions during this transition. Here， the terminal Ediacaran and early Cambrian microbialite types and theirdepositional environments in the Tarim Basin were analysed using optical microscopy， SEM (Scanning Electron Microscopy)， andraman spectroscopy. Three types of microbialites (microbial laminite， stromatolite， and thrombolite) occur in both the Ediacaran Qigebulak Formation and the Cambrian Xiaoerbulak Formation. Moreover， thrombolitic laminite， renalcis framestone， and foam spongy dolostone are identified in the Xiaoerbulak Formation. The Qigebulak Formation features upward energy-enhancing cycles from intertidal-subtidal to grain bank facies， while the Xiaoerbulak Formation records a sedimentary transition from restricted to open platform environments. Across this interval， microbialites exhibit: (i) a slight decline in microbial carbonate abundance， marked by reduced microbial laminite and increased thrombolite; (ii) increased microbial diversity， evidenced by more varied microbialite types and the preservation of more complex organic matter; and (iii) the emergence of calcified filaments in early Cambrian microbial laminites. These variations likely record microbial evolutionary responses to extrinsic paleoenvironmental changes. These findings are significant for those focusing on paleo-environmental evolution during the Ediacaran-Cambrian transition.
At present, with the improvement of people's living standards, food borne pathogens, as one of the biggest threats to food safety, are widely valued by people. Therefore, it is urgent to create a fast and efficien...
详细信息
An ISAC (Integrated System for Autonomous Control) system that fulfills severe requirements for important objectives is the topic of this research, which explores the obstacles and possibilities involved with its crea...
详细信息
Complex and complex neurological illnesses like Parkinson's disease (Pd) are difficult to investigate. This publication introduces 'Neural Pathway Profiling for Parkinson's disease drug discovery.' It ...
详细信息
A microstructure composed of martensite matrix,lower bainite,and stable film-like austenite was designed by a quenching and isothermal bainitic holding process in a 0.30C–2.69Mn–1.71Si(wt.%)*** yield strength,tensil...
详细信息
A microstructure composed of martensite matrix,lower bainite,and stable film-like austenite was designed by a quenching and isothermal bainitic holding process in a 0.30C–2.69Mn–1.71Si(wt.%)*** yield strength,tensile strength,andductile-to-brittle transition temperature(dBTT)of the high-strength steel thus obtained were 1263 MPa,1521 MPa,and-33℃,respectively,and at-20℃,it showed superior low-temperature toughness,which reached 77.5 J/cm^(2).Meanwhile,it showed excellent hydrogen embrittlement(HE)resistance,and the total elongation loss is only 3.1%after 15 min of hydrogen *** excellent comprehensive performance is attributed to the fact that fine stable austenite with film-like morphology hindered the crack nucleation and propagation,and hindered hydrogen diffusion as a hydrogen ***,with a decrease in the isothermal temperature,transition carbide precipitation was accompanied by a furtherdecrease in austenite grain *** this condition,although transition carbides can act as effective hydrogen traps,excessive precipitation decreased the carbon content of retained austenite and increased the deformation heterogeneity between austenite and martensite matrix,leading to weakened austenite stability and HE resistance,a total elongation loss of approximately 39%(15 min hydrogen charging),a sharp decrease in impact toughness,and an increase in *** competitive role of film-like austenite and transition carbides on the comprehensive mechanical performance of steel is revealed,especially the suppression of crack nucleation and propagation that will provide a guide for the design of high strength steels with excellent impact toughness and HE resistance.
Petroleum and natural gas are pivotal in the energy sector, with drilling as the primary extraction method involving machine-driven drill bits for excavating underground andretrieving resources. Similar to various in...
详细信息
ISBN:
(数字)9798350389487
ISBN:
(纸本)9798350389494
Petroleum and natural gas are pivotal in the energy sector, with drilling as the primary extraction method involving machine-driven drill bits for excavating underground andretrieving resources. Similar to various industrial processes, drilling efficiency is significantly affected by vibration-related issues, influencing petroleum extraction outcomes. To systematically identify vibrations during drilling, we developed a data collection system covering both surface anddownhole components. The surface component primarily records parameters observedduring drilling, while the downhole part integrates into the drilling tool, positioned near the drill bit to capture three-axis vibration signals. The amalgamation of data from both surface anddownhole components facilitates the annotation of harmful vibrations. Using LSTM-FCN, we enhance vibration identification by processing surface anddownhole data. Our SampleFusion (SF) algorithm further improves recognition by combining LSTM for surface and FCN fordownhole data. This integrated approach enhances real-time monitoring and classification of drilling vibrations, contributing to industry efficiency and safety.
暂无评论