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排序方式: 共有105条查询结果,搜索用时 315 毫秒
11.
This paper presents a novel approach for simultaneous power generation and harmonic current mitigation using variable speed WECS with DFIG. A new control strategy is proposed to upgrade the DFIG control to achieve simultaneously a green active and reactive power source with active filtering capability. To ensure high filtering performance, we studied an improved harmonic isolator in the time-domain, based on a new high selectivity filter developed in our laboratory. We examined two solutions for harmonic current mitigation: first, by compensating the whole harmonic component of the grid currents or second, by selective isolation of the predominant harmonic currents to ensure active filtering of the 5th and 7th harmonics. Simulation results for a 3 MW WECS with DFIG confirm the effectiveness and the performance of the two proposed approaches. 相似文献
12.
Shaghayegh Baradaran Ghavami Hamid Asadzadeh Aghdaei Dario Sorrentino Shabnam Shahrokh Maryam Farmani Fatemeh Ashrafian Maria Pina Dore Shahrbanoo Keshavarz Azizi Raftar Seyed Mobin Khoramjoo Mohammad Reza Zali 《International journal of molecular sciences》2021,22(15)
Inflammatory bowel diseases (IBDs) are immune-mediated, chronic relapsing diseases with a rising prevalence worldwide in both adult and pediatric populations. Treatment options for immune-mediated diseases, including IBDs, are traditional steroids, immunomodulators, and biologics, none of which are capable of inducing long-lasting remission in all patients. Dendritic cells (DCs) play a fundamental role in inducing tolerance and regulating T cells and their tolerogenic functions. Hence, modulation of intestinal mucosal immunity by DCs could provide a novel, additional tool for the treatment of IBD. Recent evidence indicates that probiotic bacteria might impact immunomodulation both in vitro and in vivo by regulating DCs’ maturation and producing tolerogenic DCs (tolDCs) which, in turn, might dampen inflammation. In this review, we will discuss this evidence and the mechanisms of action of probiotics and their metabolites in inducing tolDCs in IBDs and some conditions associated with them. 相似文献
13.
This paper investigates the factors affecting adoption of new irrigation technologies and also addresses the linkage between
this type of technology and production risk. The risk-premium associated with the use of water is estimated by adapting a
moment-based approach. Farm-level data were collected from a sample of 187 wheat farms, located in the three major districts
of Fars province of Iran during the years 2002 and 2003. Results of this study demonstrate that the risk premium decrease
with new irrigation technology. Also, it is concluded that the farmer-specific relative risk premium has positive and significant
effect on the decision to adopt the new irrigation technologies. So, farmers that are more risk-averse with respect to their
use of water are more likely to adopt new irrigation technologies that allow them to save water and decrease their production
(yield) risk. 相似文献
14.
Motevali Bashi Naeini Elaheh Akhoond-Ali Ali Mohammad Radmanesh Fereydoun Koupai Jahangir Abedi Soltaninia Shahrokh 《Water Resources Management》2021,35(14):4855-4875
Water Resources Management - Concerning the various effects of climate change on intensifying extreme weather phenomena all around the world, studying its possible consequences in the following... 相似文献
15.
Ghassemi Bahareh Estaji Sara Mousavi Seyed Rasoul Nemati Mahand Saba Shojaei Shahrokh Mostafaiyan Mehdi Arjmand Mohammad Khonakdar Hossein Ali 《Journal of Materials Science》2022,57(14):7250-7264
Journal of Materials Science - The present study evaluates the effect of adding different contents of hydroxyapatite (HA) nanoparticles on the mechanical properties of poly(lactic... 相似文献
16.
This paper proposes a new method for design of a dual-frequency near field-focused (NFF) antenna. A 4 × 4 array of dual-band patches and a dual-band feed network are designed to provide a phase distribution at 2.4 and 5.8 GHz. Rectangular patches with U-shaped slot be used as the double-band patches. The composite right/left handed transmission lines (CRLH TL) are used in design of a dual-band phase distribution network for the patches. Finally, a three-dimensional cubic structure is proposed to isolate the feed network and thereby improve the antenna performance. A prototype of a cubic dual band 4 × 4 near field focused array antenna is fabricated and tested. The measurement results have good agreement with simulation results. 相似文献
17.
Face to the growing number of applications using DC–DC power converters, the improvement of their reliability is subject to an increasing number of studies. Especially in safety critical applications, designing fault-tolerant converters is becoming mandatory. In this paper, a switch fault-tolerant DC–DC converter is studied. First, some of the fastest Fault Detection Algorithms (FDAs) are recalled. Then, a fast switch FDA is proposed which can detect both types of failures; open circuit fault as well as short circuit fault can be detected in less than one switching period. Second, a fault-tolerant converter which can be reconfigured under those types of fault is introduced. Hardware-In-the-Loop (HIL) results and experimental validations are given to verify the validity of the proposed switch fault-tolerant approach in the case of a single switch DC–DC boost converter with one redundant switch. 相似文献
18.
Shahrokh Hosseini-Hashemi Mohammad Reza Ilkhani Mohammad Fadaee 《Acta Mechanica》2012,223(5):1101-1118
Free vibration of Levy-type thick functionally graded (FG) circular cylindrical shell panels is investigated to identify the
validity range of two common shell theories namely Donnell and Sanders theories. FG material properties change through the
thickness direction according to a power law distribution. The state space approach is applied to solve the problem. The present
results are compared with those of the literature and a 3D finite element model for isotropic and FG materials. The effects
of various geometry and material parameters on the validity range of these theories are studied for different boundary conditions.
The results show that unlike Sanders theory, Donnell one cannot accurately capture natural boundary conditions such as force
and moment resultants. 相似文献
19.
20.
Vane liquid–gas demisters are widely used as one of the most efficient separators. To achieve higher liquid disposal and to avoid flooding, vanes are enhanced with drainage channels. In this research, the effects of drainage channel geometry parameters on the droplet removal efficiency have been investigated applying CFD techniques. The observed parameters are channel angle, channel height and channel length. The gas phase flow field was determined by the Eulerian method and the droplet flow field and trajectories were computed applying the Lagrangian method. The turbulent dispersion of the droplets was modeled using the discrete random walk (DRW) approach. The CFD simulation results indicate that by applying DRW model, the droplet separation efficiency predictions for small droplets are closer to the corresponding experimental data. The CFD simulation results showed that in the vane, enhanced with drainage channels, fewer low velocity sectors were observed in the gas flow field due to more turbulence. Consequently, the droplets had a higher chance of hitting the vane walls leading to higher separation efficiency. On the other hand, the parameters affect the liquid droplet trajectory leading to the changes in separation efficiency and hydrodynamic characteristic of the vane. To attain the overall optimum geometry of the drainage channel, all three geometry parameters were simultaneously studied employing 27 CFD simulation cases. To interpolate the overall optimal geometry a surface methodology method was used to fit the achieved CFD simulation data and finally a polynomial equation was proposed. 相似文献