To study the force of foundation of the transmission tower-line system under wind load, refined finite element models of the transmission tower-line system and the foundation were established. First, the wind load time history of the transmission tower-line system was simulated. The response of the structure was calculated by the dynamic analysis method and a comprehensive assessment of the ultimate wind-resistant bearing capacity of the transmission line was conducted. The force of the foundation of the transmission tower line system under the action of wind load was obtained. The force was applied to the foundation and the dynamic analysis of the pile foundation was conducted based on the reaction time history of the dangerous foundation, then the crack form of the foundation was predicted through the index of main tensile stress of the concrete foundation. The results show that the first 228 modes of the three-tower and two-line system are all vibrations of the ground line, and then the tower body will vibrate in the vertical direction; under wind loads, the tower legs on the windward side of the transmission tower are weaker; under the wind speed of 40m/s, the maximum main tensile stress of the pile foundation concrete is at the edge of the anchor bolt, which is close to the cracking strength of the concrete; when the pile foundation is tensioned, the stress distribution of the local concrete around a single anchor bolt forms a cone shape. After the stress is superimposed, a large stress ring area is formed on the surface of the foundation. When the concrete is tensioned and cracked, it will be damaged in the form of a cone. The force analysis results of the transmission tower foundation under wind load show the more dangerous parts of the foundation and provide theoretical guidance for the design and reinforcement of the foundation in the project.
Hybrid structure with electric cables and overhead lines are widely used in the 10 kV urban distribution network. In this paper, simulating conditions of the hybrid network are analyzed as an example, a fault simulation test platform combined of bare conductor, insulated conductor and insulators are established, the failure and the influencing factors are analyzed. The results show that: (1) the insulation damage of insulated conductors is the main reason of the line broken; (2) insulation damage will cause the vicious cycle of equipment insulation, which will causes the insulation damage of cable accessories, and then lead to the fault of the hybrid 10 kV distribution network. Aiming at the fault risk of the hybrid 10 kV distribution network, this paper puts forward some applicable countermeasures. The related research results can provide technical reference for the operation and maintenance of the hybrid 10 kV distribution network.
In this paper, an H∞ design method for assigned poles region is proposed. The method considers closed-loop dynamic performance, robustness and controller's stability as a whole. A method of obtaining optimal controller using real parameter optimization is given. An inverted pendulum equilibrium controller is designed using the proposed method. Simulation results show that, compared with the controllers designed by LQ and conventional H∞ design methods, the controller designed by the proposed method has the advantages of strong robust stability, good closed-loop dynamic performance and stable controller. Hence, the proposed method has good application prospect.
The wavelength filter synthesis problem in distributed feedback reflection filters is solved using variational optimization. Near ideal response is achievefi by using appropriate window functions. These responses have the narrowest stopband widths for a particular side-lobe suppression level. In particular, an analytic design formula approximating these ideal windowing functions is given for filters requiring -30 dB to -60-dB sidelobe suppression.
A polarization-independent optical resonator based on a novel phase-shifted grating structure is proposed and analyzed. Its application as a polarization-independent optical wavelength filter with ultranarrow bandwidth and fine tunability is described.
One key problem of a CSCAD software platform is its open structure. Based upon the object oriented approach, the paper proposes the open system structure design of IntelDes 3.0, a control system intelligent design platform developed by the authors, in which the idea of "modulization of control system design method" is first introduced. The platform deals with various model data types by the term of control object class. The development of a secondary development platform is studied to provide the compatibility feature among different software platforms. This design method has a promising application to CSCAD development and may benefit the normalization and commercialization of CSCAD software platforms.
To explore the role of nitrogen atoms in biochar-catalyzed persulfate degradation, pristine biochar and nitrogen-doped biochar were prepared and characterized. As the nitrogen doping ratio increased from 1:0 to 1:3, the removal rate of dimethomorph increased from 16.6% to 86.8%. More importantly, there is a good linear relationship (R 2 = 0.965) between the degradation rate and the content of N atoms in the biochar, which confirmed that the significant role of the N atom in the catalytic reaction. The experiments showed that during the process of biochar activation of potassium hydrogen persulfate to degrade dimethomorph, 1 O 2 , ·OH and O 2.− were all involved in the degradation process, 1 O 2 was the main contributor. A total of 8 dimethomorph catalytic degradation products were identified, and their degradation pathways were analyzed. These results will facilitate the production of cheap and efficient non-metal catalysts for reducing the risk of dimethomorph.
Mechanobiology In article 2201830 by Lining Arnold Ju and co-workers, a 3D-rendered tibia bone, featuring an observation window located in its diaphysis region, reveals a bone marrow that is abundant in vasculature. During exercise, the central arteries and transverse arterioles experience substantial surface stresses, which are then transferred from the cortical bone to the more pliable bone marrow through a process known as mechanopropagation.
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