检索结果-内蒙古大学图书馆

The Influence of Alkyl Spacers and Molecular Weight on the Charge Transport and Storage Properties of Oxy-Bithiophene-Based Conjugated Polymers

引用

Angewandte Chemie 2024年第6期137卷

作者： Hang Yu Adam Marks Sachetan M. Tuladhar Nicholas Siemons Iona Anderson Sophia Bidinger Scott T. Keene Tyler J. Quill Ruiheng Wu Olivia Gough Guanchen Wu Flurin Eisner Alberto Salleo Jonathan Rivnay George G. Malliaras Piers R. F. Barnes Iain McCulloch Jenny Nelson Department of Physics and Centre for Processable Electronics Imperial College London SW7 2AZ London United Kingdom Department of Chemistry University of Oxford OX1 2JD Oxford United Kingdom Department of Materials Science and Engineering Stanford University 94305 Stanford CA United States Department of Engineering University of Cambridge CB3 0FA Cambridge United Kingdom Department of Biomedical Engineering Northwestern University 60208 Evanston IL United States Andlinger Center for Energy and the Environment Department of Electrical and Computer Engineering Princeton University 08544 Princeton NJ United States

Conjugated polymers (CPs) with polar side chains can conduct electronic and ionic charges simultaneously, making them promising for bioelectronics, electrocatalysis and energy storage. Recent work showed that adding alkyl spacers between CP backbones and polar side chains improved electronic charge carrier mobility, reduced swelling and enhanced stability, without compromising ion transport. However, how alkyl spacers impact polymer backbone conformation and, subsequently, electronic properties remain unclear. In this work, we design two oxy-bithiophene-based CP series, each featuring progressively extended alkyl spacer lengths and two distinct molecular weight (MW) distributions. Using operando characterisations, we evaluate the (spectro)electrochemical and swelling properties of the polymer thin films, and their performance in organic field-effect transistors and organic electrochemical transistors. Surprisingly, alkyl spacers negatively impact the hole mobility of our polymers, with higher MW amplifying this effect. Using molecular dynamics simulations, we show that it is thermodynamically favourable for adjacent non-polar alkyl spacers to aggregate in polar electrolytes, leading to backbone twisting. Further spectroscopic measurements corroborate this prediction. Our findings demonstrate the active interactions between side chain structure, MW and electrolyte/solvent polarity in influencing polymer performance, underscoring the importance of considering solvation environment effects on polymer conformation when designing new mixed conducting CPs for electrochemical applications.

关键词： Conformation analysis Conjugated polymers Electrochemistry Molecular dynamics Polymer-solvent interactions

来源：评论

学校读者我要写书评

暂无评论

An Evolutionary Computation Approach for Smart Grid Cascading Failure Vulnerability Analysis

An Evolutionary Computation Approach for Smart Grid Cascadin...

引用

IEEE Symposium Series on Computational Intelligence (SSCI)

作者： He Jiang Zhenhua Wang Haibo He Department of Electrical Computer and Biomedical Engineering University of Rhode Island Kingston RI USA

ISBN: (数字)9781728124858

ISBN: (纸本)9781728124865

The cyber-physical security of smart grid is of great importance since it directly concerns the normal operating of a system. Recently, researchers found that organized sequential attacks can incur large-scale cascading failure to the smart grid. In this paper, we focus on the line-switching sequential attack, where the attacker aims to trip transmission lines in a designed order to cause significant system failures. Our objective is to identify the critical line-switching attack sequence, which can be instructional for the protection of smart grid. For this purpose, we develop an evolutionary computation based vulnerability analysis framework, which employs particle swarm optimization to search the critical attack sequence. Simulation studies on two benchmark systems, i.e., IEEE 24 bus reliability test system and Washington 30 bus dynamic test system, are implemented to evaluate the performance of our proposed method. Simulation results show that our method can yield a better performance comparing with the reinforcement learning based approach proposed in other prior work.

关键词： Power transmission lines Smart grids Power system faults Power system protection Topology Evolutionary computation

来源：评论

学校读者我要写书评

暂无评论

Pre-whitening and Null Projection as an Artifact Suppression Method for Electrocorticography Stimulation in Bi-Directional Brain computer Interfaces

Pre-whitening and Null Projection as an Artifact Suppression...

引用

Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Jeffrey Lim Po T. Wang Susan J. Shaw Michelle Armacost Hui Gong Charles Y. Liu An H. Do Payam Heydari Zoran Nenadic Department of Biomedical Engineering University of California Irvine (UCI) Irvine CA USA Rancho Los Amigos National Rehabilitation Center Downey CA USA Department of Neurology UCI Irvine CA USA Department of Electrical Engineering and Computer Science UCI Irvine CA USA

ISBN: (数字)9781728119908

ISBN: (纸本)9781728119915

Electrocorticography (ECoG)-based bi-directional (BD) brain-computer interfaces (BCIs) are a forthcoming technology promising to help restore function to those with motor and sensory deficits. A major problem with this paradigm is that the cortical stimulation necessary to elicit artificial sensation creates strong electrical artifacts that can disrupt BCI operation by saturating recording amplifiers or obscuring useful neural signal. Even with state-of-the-art hardware artifact suppression methods, robust signal processing techniques are still required to suppress residual artifacts that are present at the digital back-end. Herein we demonstrate the effectiveness of a pre-whitening and null projection artifact suppression method using ECoG data recorded during a clinical neurostimulation procedure. Our method achieved a maximum artifact suppression of 21.49 dB and significantly increased the number of artifact-free frequencies in the frequency domain. This performance surpasses that of a more traditional independent component analysis methodology, while retaining a reduced complexity and increased computational efficiency.

关键词： Electrodes Interference Frequency-domain analysis Standards Bidirectional control Electroencephalography Indexes

来源：评论

学校读者我要写书评

暂无评论

Data-driven uncertainty quantification in computational human head models

arXiv

引用

arXiv 2021年

作者： Upadhyay, Kshitiz Giovanis, Dimitris G. Alshareef, Ahmed Knutsen, Andrew K. Johnson, Curtis L. Carass, Aaron Bayly, Philip V. Shields, Michael D. Ramesh, K.T. Hopkins Extreme Materials Institute Johns Hopkins University BaltimoreMD21218 United States Department of Mechanical Engineering Johns Hopkins University BaltimoreMD21218 United States Department of Civil and Systems Engineering Johns Hopkins University BaltimoreMD21218 United States Department of Electrical and Computer Engineering Johns Hopkins University BaltimoreMD21218 United States Center for Neuroscience and Regenerative Medicine The Henry M. Jackson Foundation for the Advancement of Military Medicine BethesdaMD20814 United States Department of Biomedical Engineering University of Delaware NewarkDE19716 United States Mechanical Engineering and Materials Science Washington University in St. Louis St. LouisMO63130 United States

Computational models of the human head are promising tools for estimating the impact-induced strain response of brain, and thus play an important role in the study and prediction of traumatic brain injury. Modern biofidelic head model simulations are associated with very high computational cost, and high-dimensional inputs and outputs, which limits the applicability of traditional uncertainty quantification (UQ) methods on these systems. In this study, a data-driven manifold learning-based surrogate modeling framework is proposed for UQ of computational head models. This framework is demonstrated on a specific model problem of a 2D subject-specific head model, where the goal is to quantify uncertainty in the simulated strain fields (i.e., output), given the variability in the material properties of different brain substructures (i.e., input). In the first stage of the proposed framework, a data-driven method based on multi-dimensional Gaussian kernel-density estimation and diffusion maps is used to generate realizations of the input random vector of material properties directly from the available data. Computational simulations of a small number of realizations provide input-output pairs for training data-driven surrogate models in the second stage. The surrogate models employ nonlinear dimensionality reduction using Grassmannian diffusion maps to identify a latent representation of the strain fields, Gaussian process regression to create a low-cost mapping between the input random vector and the reduced solution space, and geometric harmonics models for mapping between the reduced space and the Grassmann manifold. It is demonstrated that the surrogate models, even with small training dataset, lead to highly accurate approximations of the computational model while significantly reducing the computational cost. Monte Carlo simulations of the surrogate models are used for uncertainty propagation. UQ of strain fields highlight significant spatial variation in model unc

关键词： Uncertainty analysis

来源：评论

学校读者我要写书评

暂无评论

Short-term forecasting of Italian gas demand

arXiv

引用

arXiv 2019年

作者： Marziali, Andrea Fabbiani, Emanuele De Nicolao, Giuseppe Modelling and Pricing A2A Department of Electrical Computer and Biomedical Engineering University of Pavia

Forecasting natural gas demand is a key problem for energy providers, as it allows for efficient pipe reservation and power plant allocation, and enables effective price forecasting. We propose a study of Italian gas demand, with particular focus on industrial and thermoelectric components. To the best of our knowledge, this is the first work about these topics. After a preliminary discussion on the characteristics of gas demand, we apply several statistical learning models to perform day-ahead forecasting, including regularized linear models, random forest, support vector regression and neural networks. Moreover, we introduce four simple ensemble models and we compare their performance with the one of basic forecasters. The out-of-sample Mean Absolute Error (MAE) achieved on 2017 by our best ensemble model is 5.16 Millions of Standard CubicMeters (MSCM), lower than 9.57 MSCM obtained by the predictions issued by SNAM, the Italian Transmission System Operator (TSO). Copyright © 2019, The Authors. All rights reserved.

关键词： Natural gas

来源：评论

学校读者我要写书评

暂无评论

Relative Degree Identification for Sliding Mode Controllers Design 15

Relative Degree Identification for Sliding Mode Controllers ...

引用

15th International Workshop on Variable Structure Systems, VSS 2018

作者： Rinaldi, Gianmario Ferrara, Antonella University of Pavia Department of Electrical Computer and Biomedical Engineering Pavia Italy

ISBN: (纸本)9781538664391

In this paper, a novel approach to identify the relative degree of nonlinear uncertain single-input single-output systems is presented. The proposed approach can be profitably used to design sliding mode controllers even for systems with unknown relative degree. Assuming to measure only the output of the system and to apply a prescribed triangular input signal, we prove that a set of inequalities holds only for the r-th time derivative of the output, where r is the relative degree. A practical algorithm for the relative degree identification is also proposed. This makes use of the theoretical key-findings and relies on the use of successive higher order sliding mode differentiators. A numerical test case is discussed to show the effectiveness of the proposed scheme. © 2018 IEEE.

关键词： Sliding mode control

来源：评论

学校读者我要写书评

暂无评论

Efficient spectrum sharing using femtocells for wireless networks

引用

AIP Conference Proceedings 2022年第1期2405卷

作者： Nami Susan Kurian Julie Joan N. S. Kathu Sara Renji Vaijayanthimala J. K. 1Department of Electronics and Communication Engineering Rajalakshmi Institute of Technology Chennai Tamil Nadu 600124 India 2Department of Computer Science Engineering Anna University Chennai Tamil Nadu 600025 India 3Department of Biomedical Engineering VSB Engineering College Karur Tamil Nadu 639111 India 4Department of Electrical and Electronics Engineering AMET University Kanathur Tamil Nadu 603112 India

Cellular phones face issues of low signal power and reduced call quality when intended to use in the interior environment. Though the traditional method of using distributed antenna systems, somehow overcomes this issue but has many limitations too. As a result, this paper suggested a model that address the shortcomings of the previously described method by implementing a wireless framework to curb the reduced signal quality in indoor communication. In the proposed protocol, we have designed a compact, low-power cellular base station called Femtocells, which helps service providers or base stations to extend indoor service coverage and provide better signal quality. This can be used in both residential and enterprise areas. These cellular access points provide communication between the local Femtocells are essentially a form of the cellular access point that provides communication between the mobile phones and internet. The algorithm used behind this is AODV Routing Protocol and it operates in two different phases: Route Discovery and Route maintenance mechanism. The primary task of femtocells is to allocate the vacant spectrum to its users from the main base station by using the cognitive radio technology. Thus, the users can communicate efficiently without any drop calls even when the signal strength is very less as femtocells effectively extend the cell coverage and capacity. When compared to Distributed Antenna System, the proposed technique is completely wireless, low cost and guarantees signal strength to a greater extend.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Decentralized Integral Sliding Mode Approach for Frequency Control and Unknown Demand Reconstruction in Power Systems 15

Decentralized Integral Sliding Mode Approach for Frequency C...

引用

15th International Workshop on Variable Structure Systems, VSS 2018

作者： Rinaldi, Gianmario Ferrara, Antonella University of Pavia Department of Electrical Computer and Biomedical Engineering Pavia Italy

ISBN: (纸本)9781538664391

This paper deals with the design of a decentralized integral sliding mode approach to control the frequency in power systems partitioned into control areas. In this approach, the frequency and the total electrical active power exchanged are both locally measured in each area via Phasor Measurement Units (PMUs). A robust integral sliding mode control scheme with chattering alleviation is designed to steer to zero the frequency deviation in each control area. Furthermore, a method to locally reconstruct the unknown electrical active power demand is presented. The proposed method has the merit to be robust with respect to matched uncertainties and unmodeled dynamics in contrast to conventional control methods often based on linearized models. Numerical simulations are discussed to assess our approach. © 2018 IEEE.

关键词： Phasor measurement units

来源：评论

学校读者我要写书评

暂无评论

Optimal control modulation of HIV reservoir formation rate by antigen infusion

Optimal control modulation of HIV reservoir formation rate b...

引用

IEEE Annual Conference on Decision and Control

作者： Aditya Jagarapu Michael J. Piovoso Ryan Zurakowski Department of Biomedical Engineering University of Delaware Newark DE Department of Electrical and Computer Engineering University of Delaware Newark DE

ISBN: (数字)9781728113982

ISBN: (纸本)9781728113999

The Human Immunodeficiency Virus (HIV) infects helper-T cells, and takes advantage of the naturally occurring quiescent phenotype of T cells to persist even under effective treatment conditions. If an infected cell does not produce virus and enters this quiescent state, it forms a natural reservoir that is not targeted by either the existing antiretroviral drugs or the immune system. These quiescent cells intermittently switch to an activated phenotype and begin to produce virus, and are the primary source of viral rebound following treatment cessation. Recent experimental results have shown that, despite this reservoir having a years-long half-life under treatment, most of the cells in the reservoir were infected in a few weeks prior to the start of treatment. This can only be explained by assuming that this reservoir has a short half-life off treatment and a very long half-life on treatment. In this paper, we introduce a novel model of reservoir formation and turnover explaining this difference as a result of antigen-dependent activation. We introduce a second control input through infusion of HIV antigen, mimicking the non-infection pseudovirus (PV) produced by protease inhibitor therapy. This model is coupled to an existing model of immune response to HIV. We fit the parameters of this model to the existing clinical observations of latency. We show that the use of antigen infusion therapy can result in order-of-magnitude decrease in the size of the quiescent reservoir, and that this may provide a way to rapidly stabilize a post-treatment control state in treated HIV infected individuals.

关键词： Reservoirs Immune system Viruses (medical) Mathematical model Drugs Inhibitors

来源：评论

学校读者我要写书评

暂无评论

Analysis of a matched turnstile junction by the BI-RME method and the segmentation technique

Analysis of a matched turnstile junction by the BI-RME metho...

引用

2018 Baltic URSI Symposium, URSI 2018

作者： Battistutta, Simone Bozzi, Maurizio Bressan, Marco Perregrini, Luca Department of Electrical Computer and Biomedical Engineering University of Pavia Pavia Italy

ISBN: (纸本)9788394942137

This paper presents the application of the generalized Boundary Integral-Resonant Mode Expansion (BI-RME) method to the analysis of a matched turnstile junction. The segmentation technique is adopted, and the BI-RME method is extended to circular waveguide terminal ports. The BI-RME simulation results of the turnstile junction are compared with a FEM simulation, showing a good agreement and an advantage in terms of computing time and memory allocation. © 2018 Warsaw University of Technology.

关键词： Circular waveguides

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：