Topologies comparison of multi-cell medium frequency transformer for offshore farms

2010 ◽  
Author(s):  
P. Monjean ◽  
J. Delanoë ◽  
J. Auguste ◽  
C. Saudemont ◽  
J. Sprooten ◽  
...  
Keyword(s):  
Medium Frequency ◽  
Cell Medium

Pinocytotic-Like Forms of Mitochondria From Rat Anterior Pituitary

1968 ◽  
Vol 26 ◽  
pp. 146-147
Author(s):  
Burton B. Silver
Keyword(s):  
Electron Micrographs ◽  
Conformational Changes ◽  
Anterior Pituitary ◽  
Dynamic State ◽  
Surrounding Cell ◽  
The Matrix ◽  
The Moment ◽  
Cell Medium ◽  
Sectioned Tissue ◽  
State Of Activity

Sectioned tissue rarely indicates evidence of what is probably a highly dynamic state of activity in mitochondria which have been reported to undergo a variety of movements such as streaming, divisions and coalescence. Recently, mitochondria from the rat anterior pituitary have been fixed in a variety of configurations which suggest that conformational changes were occurring at the moment of fixation. Pinocytotic-like vacuoles which may be taking in or expelling materials from the surrounding cell medium, appear to be forming in some of the mitochondria. In some cases, pores extend into the matrix of the mitochondria. In other forms, the remains of what seems to be pinched off vacuoles are evident in the mitochondrial interior. Dense materials, resembling secretory droplets, appear at the junction of the pores and the cytoplasm. The droplets are similar to the secretory materials commonly identified in electron micrographs of the anterior pituitary.

Medium-frequency acoustic methods and tools for the study of the aquatic environment.

2020 ◽  
Author(s):  
N.A. Grekov ◽  
◽  
A.N. Grekov ◽  
E.N. Sychov ◽  
◽  
...  
Keyword(s):  
Aquatic Environment ◽  
Medium Frequency ◽  
Acoustic Methods

scholarly journals Delivery of Foreign Materials into Adherent Cells by Gold Nanoparticle-Mediated Photoporation

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 550
Author(s):  
Xiaofan Du ◽  
Jing Wang ◽  
Lan Chen ◽  
Zhenxi Zhang ◽  
Cuiping Yao
Keyword(s):  
Fluorescein Isothiocyanate ◽  
Adherent Cells ◽  
Thermal Dynamics ◽  
Cervical Cell ◽  
Nanosecond Pulse Laser ◽  
Fluorescein Isothiocyanate Dextran ◽  
Extracellular Materials ◽  
Foreign Materials ◽  
Cell Medium ◽  
Delivery Efficiency

Delivering extracellular materials into adherent cells presents several challenges. A homemade photoporation platform, mediated by gold nanoparticles (AuNPs), was constructed to find a suitable method for finding all adherent cells in this process with high delivery efficiency. The thermal dynamics of AuNPs could be monitored. Based on this system, 60 nm AuNPs were selected to be attached to cells for optimal photoporation. After irradiating the cells covered with AuNPs using a nanosecond pulse laser, fluorescein isothiocyanate-dextran in the medium were delivered into optoporated adherent HeLa (human cervical cell lines) cells. The delivery efficiency and cell viability of this process were evaluated using a fluorescence microscope and flow cytometry. The experimental results showed that targeting cells using antibodies, laser irradiation from the top of the cell culture well, and reducing the cell medium are important for improving the delivery efficiency. The optimal loading efficiency for adherent HeLa cells was 53.4%.

scholarly journals Miniaturization of an Offshore Platform with Medium-Frequency Offshore Wind Farm and MMC-HVDC Technology

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2058
Author(s):  
Zheren Zhang ◽  
Yingjie Tang ◽  
Zheng Xu
Keyword(s):  
Wind Power ◽  
Computer Aided Design ◽  
Wind Farm ◽  
Offshore Platform ◽  
Offshore Wind ◽  
Operating Frequency ◽  
Offshore Wind Farm ◽  
Medium Frequency ◽  
Offshore Wind Power ◽  
System Frequency

Offshore wind power has great development potential, for which the key factors are reliable and economical wind farms and integration systems. This paper proposes a medium-frequency wind farm and MMC-HVDC integration system. In the proposed scheme, the operating frequency of the offshore wind farm and its power collection system is increased from the conventional 50/60 Hz rate to the medium-frequency range, i.e., 100–400 Hz; the offshore wind power is transmitted to the onshore grid via the modular multilevel converter-based high-voltage direct current transmission (MMC-HVDC). First, this paper explains the principles of the proposed scheme in terms of the system topology and control strategy aspects. Then, the impacts of increasing the offshore system operating frequency on the main parameters of the offshore station are discussed. As the frequency increases, it is shown that the actual value of the electrical equipment, such as the transformers, the arm inductors, and the SM capacitors of the rectifier MMC, can be reduced, which means smaller platforms are required for the step-up transformer station and the converter station. Then, the system operation characteristics are analyzed, with the results showing that the power losses in the system increase slightly with the increase of the offshore AC system frequency. Based on time domain simulation results from power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC), it is noted that the dynamic behavior of the system is not significantly affected with the increase of the offshore AC system frequency in most scenarios. In this way, the technical feasibility of the proposed offshore platform miniaturization technology is proven.

scholarly journals Input Parallel Output Series Structure of Planar Medium Frequency Transformers for 200 kW Power Converter: Model and Parameters Evaluation

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1450
Author(s):  
Alessandro La Ganga ◽  
Roberto Re ◽  
Paolo Guglielmi
Keyword(s):  
Electric Vehicles ◽  
High Performance ◽  
Power Converter ◽  
Electrical Model ◽  
Solid State Transformer ◽  
Medium Frequency ◽  
Analytical Treatment ◽  
Transformer Model ◽  
Planar Medium ◽  
Parallel Output

Nowadays, the demand for high power converters for DC applications, such as renewable sources or ultra-fast chargers for electric vehicles, is constantly growing. Galvanic isolation is mandatory in most of these applications. In this context, the Solid State Transformer (SST) converter plays a fundamental role. The adoption of the Medium Frequency Transformers (MFT) guarantees galvanic isolation in addition to high performance in reduced size. In the present paper, a multi MFT structure is proposed as a solution to improve the power density and the modularity of the system. Starting from 20kW planar transformer model, experimentally validated, a multi-transformer structure is analyzed. After an analytical treatment of the Input Parallel Output Series (IPOS) structure, an equivalent electrical model of a 200kW IPOS (made by 10 MFTs) is introduced. The model is validated by experimental measurements and tests.

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