基于滤波器-信赖域方法的最优潮流算法

在电力市场环境下，求解诸多问题都需要最优潮流作为理想的工具。该文基于滤波器和信赖域的思想提出了求解最优潮流的新算法：由信赖域决定线性化步长，线性规划子问题由多步中心校正原一对偶内点法进行求解，并采用了考虑电网拓扑的物理策略和动态调整线性规划子问题的收敛判据策略来改善最优潮流算法的稳定性和收敛性。该算法通过逐次求解线性规划子问题，在滤波器中利用多目标规划的优超(Domin Rllce)概念决定是否接受新的点，算法本身具有非单调的性质。通过与预测一校正方法的比较，进一步验证了多步中心校正方法的求解效率。对系统规模从14节点到662节点的7个电力系统作了全面的数值计算，计算结果表明，该算法具有较高的稳定性和快速收敛性，具有实用意义。     

The L467F-F508del Complex Allele Hampers Pharmacological Rescue of Mutant CFTR by Elexacaftor/Tezacaftor/Ivacaftor in Cystic Fibrosis Patients: The Value of the Ex Vivo Nasal Epithelial Model to Address Non-Responders to CFTR-Modulating Drugs

Loss-of-function mutations of the CFTR gene cause cystic fibrosis (CF) through a variety of molecular mechanisms involving altered expression, trafficking, and/or activity of the CFTR chloride channel. The most frequent mutation among CF patients, F508del, causes multiple defects that can be, however, overcome by a combination of three pharmacological agents that improve CFTR channel trafficking and gating, namely, elexacaftor, tezacaftor, and ivacaftor. This study was prompted by the evidence of two CF patients, compound heterozygous for F508del and a minimal function variant, who failed to obtain any beneficial effects following treatment with the triple drug combination. Functional studies on nasal epithelia generated in vitro from these patients confirmed the lack of response to pharmacological treatment. Molecular characterization highlighted the presence of an additional amino acid substitution, L467F, in cis with the F508del variant, demonstrating that both patients were carriers of a complex allele. Functional and biochemical assays in heterologous expression systems demonstrated that the double mutant L467F-F508del has a severely reduced activity, with negligible rescue by CFTR modulators. While further studies are needed to investigate the actual prevalence of the L467F-F508del allele, our results suggest that this complex allele should be taken into consideration as plausible cause in CF patients not responding to CFTR modulators.     

单周期控制的单相功率因数校正技术现状与发展

单周期控制是功率因数校正中的一种控制方法,广泛用于提高系统的动态响应速度。本文阐述了单周期控制PFC的工作原理,简要分析了目前应用的典型电路,并预测了单周期控制PFC技术的发展前景。     

Selective digital filters with quadratic phase

A method for design of a new class of digital infinite impulse response filters realized as parallel connection of two all‐pass filters is presented in this paper. A new approach to approximation of quadratic phase of all‐pass filter at all frequencies is given. Chosen parallel structure offers opportunity for realization of filters with arbitrary shape phase. The presented algorithm is based on all‐pass filter phase approximation. Phases of both all‐pass filters approximate ideal quadratic phase in minimax sense at all frequencies. Such filters can be applied for chirp signal compression or expansion. Magnitude characteristic of described filters is very selective and elliptic‐like. Obtained filters are compared with elliptic filter and group delay corrector in cascade. For the same specifications, much better results are achieved by the proposed filters. Parallel connection of all‐pass filters introduces lower signal delay, and for a given maximal phase, approximation error demands less complex network. Examples to illustrate the proposed method are given. Copyright © 2016 John Wiley & Sons, Ltd.     

Convergence acceleration of iterative algorithms. Applications to thin shell analysis and Navier–Stokes equations

This work deals with the convergence acceleration of iterative nonlinear methods. Two convergence accelerating techniques are evaluated: the Modified Mininal Polynomial Extrapolation Method (MMPE) and the Padé approximants. The algorithms studied in this work are iterative correctors: Newton’s modified method, a high-order iterative corrector presented in Damil et al. (Commun Numer Methods Eng 15:701–708, 1999) and an original algorithm for vibration of viscoelastic structures. We first describe the iterative algorithms for the considered nonlinear problems. Secondly, the two accelerating techniques are presented. Finally, through several numerical tests from the thin shell theory, Navier–Stokes equations and vibration of viscoelastic shells, the advantages and drawbacks of each accelerating technique is discussed.     

基于坐姿矫正器的“智慧书屋”交互系统设计

目的医学研究显示,坐姿、读写姿势不正确,会影响孩子骨骼的健康生长,这也是我国中小学生近视率居高不下的主要原因之一,建立以坐姿矫正器为终端的"智慧书屋"健康交互系统,可以有效降低我国中小学生的近视和脊柱弯曲变形发病率。方法针对中小学生坐姿现状及原因分析,阐述内蒙古卓姿科技有限公司开发的坐姿矫正器的优势,并以此建立"智慧书屋",通过对"智慧书屋"交互系统特性的分析,运用思维导图等方法系统地设计了以坐姿矫正器为终端的"智慧书屋"交互系统、移动终端APP。结果完成了坐姿矫正器的功能架构设计,建立了"智慧书屋"交互系统。结论通过"智慧书屋"交互系统设计,构建了健康的智能学习环境,有利于我国中小学生的健康成长和学习,对中小学生的身心健康发展具有重要意义。     

Capturing the Direct Binding of CFTR Correctors to CFTR by Using Click Chemistry

Cystic fibrosis (CF) is a lethal genetic disease caused by the loss or dysfunction of the CF transmembrane conductance regulator (CFTR) channel. F508del is the most prevalent mutation of the CFTR gene and encodes a protein defective in folding and processing. VX‐809 has been reported to facilitate the folding and trafficking of F508del‐CFTR and augment its channel function. The mechanism of action of VX‐809 has been poorly understood. In this study, we sought to answer a fundamental question underlying the mechanism of VX‐809: does it bind CFTR directly in order to exert its action? We synthesized two VX‐809 derivatives, ALK‐809 and SUL‐809, that possess an alkyne group and retain the rescue capacity of VX‐809. By using Cu^I‐catalyzed click chemistry, we provide evidence that the VX‐809 derivatives bind CFTR directly in vitro and in cells. Our findings will contribute to the elucidation of the mechanism of action of CFTR correctors and the design of more potent therapeutics to combat CF.     

Techniques to obtain single-stage power supplies with power factor correction (PFC)

In order to comply with the standards, the input current of the switch mode power supplies (SMPS) must be almost sinusoidal, i.e. the SMPS must achieve power factor correction. This requirement is normally reached with the use of an additional input converter, typically a boost, resulting in a two-stage SMPS with the inherent drawbacks: high cost and the necessity of high efficiency in each stageto obtain a reasonable global efficiency. This article introduces two simple techniques together with the control strategies that can be used to obtain single-stage SMPS, that allow the control of the output voltage and the sinusoidal input current wave shaping, without any additional stage. Another objective of this article is to investigate and to evaluate the performance of each topology that emerged from the chosen technique. Considering high-power applications, experimental results of two single-stage full-bridge topologies are also presented, in order to verify the concepts introduced in the article.     

Finite volume approximation of stiff problems on two-dimensional curvilinear domain

The aim of this article is to apply a novel finite volume method to approximate a stiff problem for a two-dimensional curvilinear domain. The stiffness is caused by the existence of a small parameter in the equation which introduces a boundary layer along parts of the curvilinear boundary. Incorporating in the finite volume space the boundary layer correctors, the boundary layer singularities are absorbed. Hence, we propose a second order scheme for curvilinear domains using uniform meshes thus avoiding the costly refinement of mesh in the boundary layers.