Southeast University

About: Southeast University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Computer science & MIMO. The organization has 66363 authors who have published 79434 publications receiving 1170576 citations. The organization is also known as: SEU.

Frequency-Adaptive Fractional-Order Repetitive Control of Shunt Active Power Filters

Abstract: Repetitive control (RC), which can achieve zero steady-state error tracking of any periodic signal with known integer period, offers active power filters (APFs) a promising accurate current control scheme to compensate the harmonic distortion caused by nonlinear loads. However, classical RC cannot exactly compensate periodic signals of variable frequency and would lead to significant performance degradation of APFs. In this paper, a fractional-order RC (FORC) strategy at a fixed sampling rate is proposed to deal with any periodic signal of variable frequency, where a Lagrange-interpolation-based fractional delay (FD) filter is used to approximate the factional delay items. The synthesis and analysis of FORC systems are also presented. The proposed FORC offers fast online tuning of the FD and the fast update of the coefficients, and then provides APFs with a simple but very accurate real-time frequency-adaptive control solution to the elimination of harmonic distortions under grid frequency variations. A case study on a single-phase shunt APF is conducted. Experimental results are provided to demonstrate the validity of the proposed FORC.

High-rate in-plane micro-supercapacitors scribed onto photo paper using in situ femtolaser-reduced graphene oxide/Au nanoparticle microelectrodes

Abstract: Direct laser-reduction of graphene oxide (GO), as a lithography-free approach, has been proven effective in manufacturing in-plane micro-supercapacitors (MSCs) with fast ion diffusion. However, the power density and the charge/discharge rate are still limited by the relatively low conductivity of electrodes. Here, we report a facile approach by exploiting femtolaser in situ reduction of the hydrated GO and chloroauric acid (HAuCl4) nanocomposite simultaneously, which incorporates both the patterning of rGO electrodes and the fabrication of Au current collectors in a single step. These flexible MSCs boast achievements of one-hundred fold increase in electrode conductivities of up to 1.1 × 106 S m−1, which provide superior rate capability (50% for the charging rate increase from 0.1 V s−1 to 100 V s−1), sufficiently high frequency responses (362 Hz, 2.76 ms time constant), and large specific capacitances of 0.77 mF cm−2 (17.2 F cm−3 for volumetric capacitance) at 1 V s−1, and 0.46 mF cm−2 (10.2 F cm−3) at 100 V s−1. The use of photo paper substrates enables the flexibility of this fabrication protocol. Moreover, proof-of-concept 3D MSCs are demonstrated with enhanced areal capacitance (up to 3.84 mF cm−2 at 1 V s−1) while keeping high rate capabilities. This prototype of all solid-state MSCs demonstrates the broad range of potentials of thin-film based energy storage device applications for flexible, portable, and wearable electronic devices that require a fast charge/discharge rate and high power density.

Minimum superlattice thermal conductivity from molecular dynamics

Abstract: The dependence of superlattice thermal conductivity on period length is investigated by molecular dynamics simulation. For perfectly lattice matched superlattices, a minimum is observed when the period length is of the order of the effective phonon mean free path. As temperature decreases and interatomic potential strength increases, the position of the minimum shifts to larger period lengths. The depth of the minimum is strongly enhanced as mass and interatomic potential ratios of the constituent materials increase. The simulation results are consistent with phonon transmission coefficient calculations, which indicate increased stop bandwidth and thus strongly enhanced Bragg scattering for the same conditions under which strong reductions in thermal conductivity are found. When nonideal interfaces are created by introducing a 4% lattice mismatch, the minimum disappears and thermal conductivity increases monotonically with period length. This result may explain why minimum thermal conductivity has not been observed in a large number of experimental studies.

Small molecule-driven NLRP3 inflammation inhibition via interplay between ubiquitination and autophagy: implications for Parkinson disease

Abstract: Aging-related, nonresolving inflammation in both the central nervous system (CNS) and periphery predisposes individuals to the development of neurodegenerative disorders (NDDs). Inflammasomes are thought to be especially relevant to immune homeostasis, and their dysregulation contributes to inflammation and NDDs. However, few agents have been clinically shown to reduce NDD incidence by targeting inflammasomes. Our study indicated that NLRP3 (NLR family, pyrin domain containing 3) inflammasome is involved in Parkinson disease (PD) progression in patients and various murine models. In addition, the small molecule kaempferol (Ka) protected mice against LPS- and SNCA-induced neurodegeneration by inhibiting NLRP3 inflammasome activation as evidenced by the fact that Ka reduced cleaved CASP1 expression and disrupted NLRP3-PYCARD-CASP1 complex assembly with concomitant decreased IL1B secretion. Mechanically, Ka promoted macroautophagy/autophagy in microglia, leading to reduced NLRP3 protein expression, which in turn deactivated the NLRP3 inflammasome. Intriguingly, ubiquitination was involved in Ka-induced autophagic NLRP3 degradation. These findings were further confirmed in vivo as knockdown of Atg5 expression or autophagy inhibitor treatment significantly inhibited the Ka-mediated NLRP3 inflammasome inhibition and neurodegeneration amelioration. Thus, we demonstrated that Ka promotes neuroinflammatory inhibition via the cooperation of ubiquitination and autophagy, suggesting that Ka is a promising therapeutic strategy for the treatment of NDDs. Abbreviations: 3-MA: 3-methyladenine; AAV: adeno-associated virus; ACTB: actin, beta; AIF1/IBA1: allograft inflammatory factor 1; ATG5: autophagy related 5; ATG7: autophagy related 7; BafA1: bafilomycin A1; BECN1: beclin 1, autophagy related; CASP1: caspase 1; CNS: central nervous system; CQ: chloroquine; DA neurons: dopaminergic neurons; DAMPS: damage-associated molecular patterns; DAPI: 4',6-diamidino-2-phenylindole; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; GFAP: glial fibrillary acidic protein; IP: immunoprecipitation; i.p.: intraperitoneally; Ka: kaempferol; KD: knockdown; KO: knockout; LPS: lipopolysaccharide; IL1B: interleukin 1 beta; IL6: interleukin 6; Ly: lysate; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MPTP: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; NC: negative control; NDD: neurodegenerative diseases; NLRP3: NLR family, pyrin domain containing 3; OE: overexpression; PD: Parkinson disease; poly-Ub: poly-ubiquitin; PTM: post-translational modification; PYCARD/ASC: PYD and CARD domain containing; Rapa: rapamycin; RFP: red fluorescent protein; SN: supernatant; SNCA: synuclein alpha; SNpc: substantia nigra pars compacta; SQSTM1: sequestosome 1; TH: tyrosine hydroxylase; TNF/TNF-alpha: tumor necrosis factor; Ub: ubiquitin; WT: wild type.