Active power filter control strategy with novel dual-repetitive controller and neural network adaptive PI control

U ovom je radu analizirana konfiguracija karakteristična za razdjelni aktivni filtar snage (SAPF) s dvodijelnim kondenzatorom kao i njegov glavni dijagram i upravljački modul. U svrhu poboljšanja dinamičke performanse upravljačkog sustava i pojačanja dinamičkog odziva, predstavljena je kombinirana strategija zasnovana na dvostruko-ponavljajućem kontrolnom uređaju (DRC) i adaptivnom PI upravljanju. U DRC-u jedan ponavljajući kontrolni uređaj je za osiguranje točnosti strujnog toka, a drugi za poboljšanje dinamičkog odziva. Prihvaćeno je PI upravljanje neuronskom mrežom da bi se poboljšala brzina odziva prilagođavanjem PI parametara, postavljajući parametre K\u27x i K\u27y online. Takva je strategija upravljanja primijenjena na simulaciju industrijskog prototipa i terensko ispitivanje. U usporedbi s uobičajenom strategijom upravljanja, eksperimentalni rezultat pokazuje da bi se kompenzacijom sustava mogle učinkovito smanjiti vrijednosti ukupne harmonijske distorzije (THD) od 26,02 %, 27,76 % i 27,60 % do 4,25 %, 4,57 % i 4,35 % za svaku fazu struje. A i puno vrijeme odziva je manje od 10 ms te u potpunosti zadovoljava standard IEEE-519.In this paper, the configuration characteristic of shunt active power filter (SAPF) with split-capacitor was analysed, as well as its principle diagram and control module. In order to improve the dynamic performance of a control system and elevate dynamic response, a combination strategy based on dual-repetitive controller (DRC) and adaptive PI control is presented. In DRC, one repetitive controller is for ensuring the current tracking accuracy and the other one is for enhancing dynamic response. The neural network PI control is adopted to improve response speed by turning the PI parameters adaptively, setting parameters K\u27x and K\u27y online. This control strategy was applied on industrial prototype simulation and field test. Comparing with the conventional control strategy, the experimental result shows that system compensation could effectively reduce the total harmonic distortion (THD) values from 26,02 %, 27,76 % and 27,60 % to 4,25 %, 4,57 % and 4,35 % for each phase of the current. And the full response time is all less than 10 ms, fully meeting the standard of IEEE-519

Multi-Layered Hydrogels for Biomedical Applications

Multi-layered hydrogels with organization of various functional layers have been the materials of choice for biomedical applications. This review summarized the recent progress of multi-layered hydrogels according to their preparation methods: layer-by-layer self-assembly technology, step-wise technique, photo-polymerization technique and sequential electrospinning technique. In addition, their morphology and biomedical applications were also introduced. At the end of this review, we discussed the current challenges to the development of multi-layered hydrogels and pointed out that 3D printing may provide a new platform for the design of multi-layered hydrogels and expand their applications in the biomedical field

H2O2-Responsive Nanoparticle Based on the Supramolecular Self-Assemble of Cyclodextrin

Designing stimuli responsive, controllable and biocompatible multifunctional nanoparticles is an important progress in the current quest for drug delivery systems. Herein, we devoted to developing a β-cyclodextrin (β-CD) based drug delivery nanoparticles (NPs) that release Bovine serum albumin (BSA) via glucose-responsive gate. The design involves synthesis of sodium alginate with β-CD modified (Alg-β-CD) and methoxypolyethylene glycol (mPEG-Fc) containing ferrocene (Fc) uncharged end-capping. When α-cyclodextrin (α-CD) was added with these two segments, the stable non-covalent supramolecular structure of Alg-β-CD/mPEG-Fc/α-CD can be self-assembled into NPs in aqueous solution. BSA loaded Alg-β-CD/mPEG-Fc/α-CD also has been prepared. Interestingly, these supramolecular Alg-β-CD/mPEG-Fc/α-CD/BSA NPs showed uniform sphere structure and constant BSA loading content. Also, this new kind of NPs can disassemble in the present of hydrogen peroxide (H2O2). Since glucose oxidase (GOD) can oxidize glucose and produce H2O2, so this kind of polymeric NPs can also have glucose responsive behavior in the GOD containing environment. Developed functional Alg-β-CD/mPEG-Fc/α-CD might be a promising drug delivery strategy for diabetes or immunotherapy with more efficiency

Cyclodextrin-based host-guest supramolecular hydrogel and its application in biomedical fields

The cyclodextrin (CD) based host-guest inclusion complexation between cyclodextrins (CDs) and guest moieties has inspired the fabrication of novel supramolecular hydrogels for biomedical applications. From a topology of view, this article reviews the recent developments of two kinds of CD-based supramolecular hydrogels and their applications in biomedical fields respectively. On one hand, supramolecular hydrogels derived from CD-based poly(pseudo)rotaxanes generally displayed thixotropic and reversible properties and have been extensively developed as injectable drug delivery systems. On the other hand, supramolecular hydrogels based on the host-guest interaction between CDs and small guest moieties generally exhibited stimuli-responsive behaviors, typically the release of therapeutic agents. The development of CD-based supramolecular hydrogels provides a new platform for the design of novel biomaterials

An Improved Vision Transformer Network with a Residual Convolution Block for Bamboo Resource Image Identification

Bamboo is an important economic crop with up to a large number of species. The distribution of bamboo species is wide; therefore, it is difficult to collect images and make the recognition model of a bamboo species with few amount of images. In this paper, nineteen species of bamboo with a total of 3220 images are collected and divided into a training dataset, a validation dataset and a test dataset. The main structure of a residual vision transformer algorithm named ReVI is improved by combining the convolution and residual mechanisms with a vision transformer network (ViT). This experiment explores the effect of reducing the amount of bamboo training data on the performance of ReVI and ViT on the bamboo dataset. The ReVI has a better generalization of a deep model with small-scale bamboo training data than ViT. The performances of each bamboo species under the ReVI, ViT, ResNet18, VGG16, Densenet121, Xception were then compared, which showed that ReVI performed the best, with an average accuracy of 90.21%, and the reasons for the poor performance of some species are discussed. It was found that ReVI offered the efficient identification of bamboo species with few images. Therefore, the ReVI algorithm proposed in this manuscript offers the possibility of accurate and intelligent classification and recognition of bamboo resource images

Double-layer microsphere incorporated with strontium doped calcium polyphosphate scaffold for bone regeneration

To design and prepare a novel controlled release system for sustained release of two drugs. In this study, a double-layer microsphere was incorporated with strontium-doped calcium polyphosphate (SCPP) scaffold to facilitate bone regeneration and achieve skull repair. The double-layer microsphere combining tetracycline loaded sodium alginate and matrix metalloproteinase-2 (MMP-2) loaded chitosan was manufactured by electrospinning, which were further adhered to SCPP scaffold. The characteristics of microstructure were observed through scanning electron microscope. Loading efficiencies and the optimal ratio of microsphere of the obtained controlled release system were investigated. In addition, the cytotoxicity and the effects on osteoblast proliferation and expressions of osteogenesis-related factors were examined in vitro. Thereafter, the compound material with the controlled release system was implanted in the skull defect of rabbit to evaluate its properties of promoting bone regeneration. The results indicated that this novel controlled release system with SCPP scaffold and the double-layer microspheres loaded with tetracycline and MMP-2 could be a promising material for bones repair