Fabrication and characterization of shape memory polymers at small scales

The objective of this research is to thoroughly investigate the shape memory effect in polymers, characterize, and optimize these polymers for applications in information storage systems. Previous research effort in this field concentrated on shape memory metals for biomedical applications such as stents. Minimal work has been done on shape memory poly- mers; and the available work on shape memory polymers has not characterized the behaviors of this category of polymers fully. Copolymer shape memory materials based on diethylene glycol dimethacrylate (DEGDMA) crosslinker, and tert butyl acrylate (tBA) monomer are designed. The design encompasses a careful control of the backbone chemistry of the materials. Characterization methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC); and novel nanoscale techniques such as atomic force microscopy (AFM), and nanoindentation are applied to this system of materials. Designed experiments are conducted on the materials to optimize spin coating conditions for thin films. Furthermore, the recovery, a key for the use of these polymeric materials for information storage, is examined in detail with respect to temperature. In sum, the overarching objectives of the proposed research are to: (i) design shape memory polymers based on polyethylene glycol dimethacrylate (PEGDMA) and diethylene glycol dimethacrylate (DEGDMA) crosslinkers, 2-hydroxyethyl methacrylate (HEMA) and tert-butyl acrylate monomer (tBA). (ii) utilize dynamic mechanical analysis (DMA) to comprehend the thermomechanical properties of shape memory polymers based on DEGDMA and tBA. (iii) utilize nanoindentation and atomic force microscopy (AFM) to understand the nanoscale behavior of these SMPs, and explore the strain storage and recovery of the polymers from a deformed state. (iv) study spin coating conditions on thin film quality with designed experiments. (iv) apply neural networks and genetic algorithms to optimize these systems.Ph.D.Committee Chair: Gall, Ken; Committee Chair: May, Gary S; Committee Member: Brand, Oliver; Committee Member: Degertekin, F Levent; Committee Member: Milor, Linda

An Ensemble Learning for Predicting Breakdown Field Strength of Polyimide Nanocomposite Films

Using the method of Stochastic Gradient Boosting, ten SMO-SVR are constructed into a strong prediction model (SGBS model) that is efficient in predicting the breakdown field strength. Adopting the method of in situ polymerization, thirty-two samples of nanocomposite films with different percentage compositions, components, and thicknesses are prepared. Then, the breakdown field strength is tested by using voltage test equipment. From the test results, the correlation coefficient (CC), the mean absolute error (MAE), the root mean squared error (RMSE), the relative absolute error (RAE), and the root relative squared error (RRSE) are 0.9664, 14.2598, 19.684, 22.26%, and 25.01% with SGBS model. The result indicates that the predicted values fit well with the measured ones. Comparisons between models such as linear regression, BP, GRNN, SVR, and SMO-SVR have also been made under the same conditions. They show that CC of the SGBS model is higher than those of other models. Nevertheless, the MAE, RMSE, RAE, and RRSE of the SGBS model are lower than those of other models. This demonstrates that the SGBS model is better than other models in predicting the breakdown field strength of polyimide nanocomposite films

Circuit paradigm in the 21

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Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

Advanced photonic and electronic systems - WILGA 2017

WILGA annual symposium on advanced photonic and electronic systems has been organized by young scientist for young scientists since two decades. It traditionally gathers more than 350 young researchers and their tutors. Ph.D students and graduates present their recent achievements during well attended oral sessions. Wilga is a very good digest of Ph.D. works carried out at technical universities in electronics and photonics, as well as information sciences throughout Poland and some neighboring countries. Publishing patronage over Wilga keep Elektronika technical journal by SEP, IJET by PAN and Proceedings of SPIE. The latter world editorial series publishes annually more than 200 papers from Wilga. Wilga 2017 was the XL edition of this meeting. The following topical tracks were distinguished: photonics, electronics, information technologies and system research. The article is a digest of some chosen works presented during Wilga 2017 symposium. WILGA 2017 works were published in Proc. SPIE vol.10445

Biosensors

A biosensor is defined as a detecting device that combines a transducer with a biologically sensitive and selective component. When a specific target molecule interacts with the biological component, a signal is produced, at transducer level, proportional to the concentration of the substance. Therefore biosensors can measure compounds present in the environment, chemical processes, food and human body at low cost if compared with traditional analytical techniques. This book covers a wide range of aspects and issues related to biosensor technology, bringing together researchers from 11 different countries. The book consists of 16 chapters written by 53 authors. The first four chapters describe several aspects of nanotechnology applied to biosensors. The subsequent section, including three chapters, is devoted to biosensor applications in the fields of drug discovery, diagnostics and bacteria detection. The principles behind optical biosensors and some of their application are discussed in chapters from 8 to 11. The last five chapters treat of microelectronics, interfacing circuits, signal transmission, biotelemetry and algorithms applied to biosensing

【研究分野別】シーズ集 [英語版]

[英語版

Ferrite-based micro-inductors for power systems on chip : from material elaboration to inductor optimisation

Les composants passifs intégrés sont des éléments clés pour les futures alimentations sur puce, compactes et présentant des performances améliorées: haut rendement et forte densité de puissance. L'objectif de ce travail de thèse est d'étudier les matériaux et la technologie pour réaliser de bobines à base de ferrite, intégrées sur silicium, avec des faibles empreintes (<4 mm ²) et de faible épaisseur (<250 µm). Ces bobines, dédiées à la conversion de puissance (˜ 1 W) doivent présenter une forte inductance spécifique et un facteur de qualité élevé dans la gamme de fréquence visée (5-10 MHz). Des ferrites de NiZn ont été sélectionnées comme matériaux magnétiques pour le noyau des bobines en raison de leur forte résistivité et de leur perméabilité stable dans la gamme de fréquence visée. Deux techniques sont développées pour les noyaux de ferrite: la sérigraphie d'une poudre synthétisée au laboratoire et la découpe automatique de films de ferrite commerciaux, suivi dans chaque cas du frittage et le placement sur les conducteurs pour former une bobine rectangulaire. Des bobines tests ont été réalisées dans un premier temps afin que la caractérisation puisse être effectuée : les propriétés magnétiques du noyau de ferrite notamment les pertes volumiques dans le noyau sont ainsi extraites. L'équation de Steinmetz a permis de corréler les courbes de pertes mesurées avec des expressions analytiques en fonction de la fréquence et de l'induction. La deuxième phase de la thèse est l'optimisation de la conception de la micro-bobine à base de ferrite, en tenant compte des pertes attendues. L'algorithme générique est utilisé pour optimiser les dimensions de la bobine avec pour objectif ; la minimisation des pertes et l'obtention de la valeur d'inductance spécifique souhaitée, sous faible polarisation en courant. La méthode des éléments finis pour le magnétisme FEMM est utilisée pour modéliser le comportement électromagnétique du composant. La deuxième série de prototypes a été réalisée afin de valider la méthode d'optimisation. En perspective, les procédés de photolithographie de résine épaisse et le dépôt électrolytique sont en cours de développement pour réaliser les enroulements de cuivre épais autour des noyaux de ferrite optimisés et ainsi former le composant complet.On-chip inductors are key passive elements for future power supplies on chip (PwrSoC), which are expected to be compact and show enhanced performance: high efficiency and high power density. The objective of this thesis work is to study the material and technology to realize small size (<4 mm²) and low profile (< 250 µm) ferrite-based on-chip inductor. This component is dedicated to low power conversion (˜ 1 W) and should provide high inductance density and high quality factor at medium frequency range (5-10 MHz). Fully sintered NiZn ferrites are selected as soft magnetic materials for the inductor core because of their high resistivity and moderate permeability stable in the frequencies range of interest. Two techniques are developed for the ferrite cores: screen printing of in-house made ferrite powder and cutting of commercial ferrite films, followed in each case by sintering and pick-and place assembling to form the rectangular toroid inductor. Test inductors were realized first so that the characterization could be carried out to study the magnetic properties of the ferrite core and the volumetric core losses. The core losses were fit from the measured curve with Steinmetz equation to obtain analytical expressions of losses versus frequency and induction. The second phase of the thesis is the design optimization for the on-chip ferrite based inductor, taking into account the expected losses. Genetic algorithm is employed to optimize the inductor design with the objective function as minimum losses and satisfying the specification on the inductance values under weak current-bias condition. Finite element method for magnetics FEMM is used as a tool to calculate inductance and losses. The second run of prototypes was done to validate the optimization method. In perspective, processes of thick-photoresist photolithography and electroplating are being developed to realize the completed thick copper windings surrounding ferrite cores