eLearning

Exciton dynamics in conducting polymer polyaniline using ultrafast spin-polarized spectroscopy

Soonyoung Cha; Yoochan Hong; Jaemoon Yang; Inhee Maeng; Seung Jae Oh; Kiyoung Jeong; Jin-Suck Suh; Seungjoo Haam; Yong-Min Huh; Hyunyong Choi 2014 Conference on Lasers and Electro-Optics (CLEO) - Laser Science to Photonic Applications, 2014

The non-equilibrium charge dynamics in conducting polymer polyaniline (PANI) have been barely understood. Utilizing ultrafast spin-resolved spectroscopy, we show that the charge dynamics in PANI is dominated by the excitonic photoresponse.

Understanding energy level alignment in PCDTBT:PC<inf>70</inf>BM solar cells

Erin L. Ratcliff; Andres Garcia; Sarah R. Cowan; Jens Meyer; K. Xerses Steirer; Sergio A. Paniagua; Anthony Giordano; Seth Marder; Neal. R. Armstrong; Antoine Kahn; David Ginley; Dana C. Olson 2012 38th IEEE Photovoltaic Specialists Conference, 2012

Blended heterojunctions continue to improve in overall efficiency, with current power conversion efficiencies (PCE) at >;7%, with interfaces being a dominating factor in improving PCE. Charge separation is dictated by energetic alignment between the donor and acceptor. Selective interlayers are used to preferentially harvest one charge via either thermodynamic or kinetic pathways. Energetic level alignment between the blend and the ...

R &amp; D of polyimide insulated JET ELM control coils for operation at 350 C

I. J. Zatz; G. H. Neilson; S. Jurczynski; M. Mardenfeld; C. Lowry 2011 IEEE/NPSS 24th Symposium on Fusion Engineering, 2011

A study has confirmed the feasibility of designing, fabricating and installing resonant magnetic field perturbation (RMP) coils in JET with the objective of controlling edge localized modes (ELM). These coils present several engineering challenges. Conditions in JET necessitate the installation of these coils via remote handling, which will impose weight, dimensional and logistical limitations. And while the encased coils are ...

Phase-matched generation of broadband terahertz radiation in a waveguide

H. Cao; R. A. Linke; A. Nahata Lasers and Electro-Optics, 2003. CLEO '03. Conference on, 2003

We demonstrate a novel waveguide geometry that allows for the phase-matched generation of broadband THz radiation. Both the optical pump beam and generated THz radiation propagate in the fundamental mode of the waveguide.

Identification and control of crystallization dynamics during sheet polymer extrusion

C. Batur; L. Thananchai Proceedings of the 1997 American Control Conference (Cat. No.97CH36041), 1997

Crystallinity control for polymer sheet extrusion processes is considered. An analytical model for the crystallinity dynamics is derived. This development is based on the continuity, momentum, energy and crystallinity equations. It is shown that the crystallinity dynamics can be linearized around a normal operating point. Based on the linearized model, the crystallinity dynamics are identified and a pole placement control ...

IEEE-USA E-Books

• Cold Plasma Processes for Surface Modification

  This chapter contains sections titled: Introduction Surface Modification of Polymers Surface Cleaning and Ashing Oxidation Surface Hardening Questions References

• Will Composite Nanomaterials Replace Piezoelectric Thin Films for Energy Transduction Applications?

  Semiconducting piezoelectric nanowires (NWs) show significant potential for application in electronic and electromechanical sensors and energy harvesters. In particular, these nanostructures can be used to build composite piezoelectric materials that could offer several advantages when integrated vertically. First, NWs of various lengths opens the possibility to fabricate composite layers thicker than standard thin films (<4 ??m). Second, low???temperature fabrication process make this technology compatible with CMOS devices and with different substrates, such as Si, polymers, plastics, metal foils, and even paper. Third, properties such as piezoelectricity, flexibility, and dielectric constant can be improved in NWs, thereby improving the performance of NW???containing composite materials. Finally, FEM simulations show that composites can provide better performance compared to piezoelectric thin films of the same thickness, and that performance can be improved by operating in compression or flexion modes by the right choice of the dielectric matrix and NW density.

• Thermoplastic Molding Compounds

  This chapter contains sections titled: Introduction Definitions of Terms Relating to Plastics Plastics Industry Engineering Thermoplastics Polymerization Reinforcements and Fillers Flame Retardants Antioxidants Ultraviolet Stabilizers Injection Molding Standard Tests Maximum Service Temperature of Thermoplastic Polymers Relative Costs of Thermoplastic Polymers Alloys Liquid Crystal Polymers (LCPS) Conducting Polymers Development Programs Market Trends Summary of Rankings of Thermoplastic Polymers Principal Thermoplastic Polymers for Electrical/Electronic Uses

• Space Charge in HVDC Extruded Insulation: Storage, Effects, and Measurement Methods

  This chapter discusses space-charge storage in HVDC extruded insulation, the relevant manifold effects, and the techniques developed by researchers in order to measure the amount and distribution of space charge stored in the insulation, and the electric field profile associated with such distribution. It reviews the theoretical background of charge injection and transport in insulating polymers. The chapter illustrates the processes that result in space-charge accumulation namely charge generation - via electronic charge injection, field-assisted thermal ionization of impurities, spatially inhomogeneous electric polarization, and steady DC current coupled with a spatially varying ratio ofpermittivity to conductivity. It also reviews the space-charge measurement methods for HVDC extruded insulation. The chapter focuses on the up-to-date developments of the best-suited techniques for measuring space charges in extruded insulation for HVDC cables. It provides a comparison between the best space-charge measurement methods for power cables: pulsed electro acoustic (PEA) versus thermal step method (TSM).

• Functional Freeform Fabrication for Physical Artificial Life

  Solid freeform fabrication (SFF) allows 3D-printing of arbitrarily shaped structures, directly from computer-aided design (CAD) data. SFF has traditionally focused on printing passive mechanical parts. Advances in this technology and developments in materials science make it feasible to begin the development of a single, compact, robotic SFF system - including a small set of materials - which can produce complete, active, functional electromechanical devices - mobile robots, for instance. We are advancing steadily toward this goal, and successes thus far have included the freeform fabrication of zinc-air batteries, conductive wiring, flexure joints, and combinations of these with thermoplastic structures. Several essential functionalities - actuation, sensing, and control electronics - still remain to be realized before complete electromechanical systems can be produced via SFF. Conducting polymers (CP) are a class of materials which can be used to produce all of these. Several SFFcompatible CP processing methods have been identified, and actuators produced via one of these have been demonstrated. When coupled in a closed-loop with an evolutionary design system, the ability to produce robots entirely via SFF becomes a bridge between the physical and the simulated, giving artificial evolution a complete physical substrate of enormous richness to explore with little or no human involvement.

• Processing Integrated Capacitors

  This chapter contains sections titled: Sputtering CVD, PECVD and MOCVD Anodization Sol-Gel and Hydrothermal Ferroelectrics Thin- and Thick-Film Polymers Thick-Film Dielectrics Interlayer Insulation Interdigitated Capacitors Capacitor Plate Materials Trimming Integrated Capacitors Commercialized Integrated Capacitor Technologies Summary References

• Sampling Techniques: Estimating Evolutionary Rates and Generating Molecular Structures

  This chapter first discusses the general problem of characterizing ensemble properties of biological systems through integration by sampling, along with the difficulties of sampling in high-dimensional space. It briefly examines the approach of rejection sampling, and discusses two general frameworks in Monte Carlo sampling, namely, the Markov chain Monte Carlo (MCMC) or Metropolis Monte Carlo method and the sequential Monte Carlo method. The chapter also discusses basic concepts such as sampling from a desired target distribution, properties of Markov chains, time reversibility, detailed balance, and the stationary state. This is followed by the example of estimating evolutionary substitution rates of amino acids. The chapter then describes the general principle of importance sampling, the approach of sequentially building up the target distribution, and the technique of resampling for variance reduction. Finally, it presents the applications in generating self-avoiding walks for studying chain polymers and calculating RNA loop entropy.

• Micro- and Nanospheres for Tissue Engineering

  The emergence of regenerative medicine has resulted in a novel interdisciplinary field that focuses on repair, replacement, and regeneration of diseased or damaged tissues or organs. As one of the most important strategies in regenerative medicine, the field of tissue engineering (which typically combines biodegradable scaffolds, (stem) cells, and bioactive signals such as growth factors) has created new possibilities to produce implantable tissues ex vivo. This chapter focuses on the most recent advances in research on micro- and nanospheres aiming at improvement of the functionality and clinical efficacy of traditional scaffolds for soft and hard tissue engineering. Depending on their origin, polymeric micro- and nanospheres can be classified as either natural or synthetic polymers, both of which have their specific pros and cons.

• No title

  Cardiac tissue engineering aims at repairing damaged heart muscle and producing human cardiac tissues for application in drug toxicity studies. This book offers a comprehensive overview of the cardiac tissue engineering strategies, including presenting and discussing the various concepts in use, research directions and applications. Essential basic information on the major components in cardiac tissue engineering, namely cell sources and biomaterials, is firstly presented to the readers, followed by a detailed description of their implementation in different strategies, broadly divided to cellular and acellular ones. In cellular approaches, the biomaterials are used to increase cell retention after implantation or as scaffolds when bioengineering the cardiac patch, in vitro. In acellular approaches, the biomaterials are used as ECM replacement for damaged cardiac ECM after MI, or, in combination with growth factors, the biomaterials assume an additional function as a depot for prolong d factor activity for the effective recruitment of repairing cells. The book also presents technological innovations aimed to improve the quality of the cardiac patches, such as bioreactor applications, stimulation patterns and prevascularization. This book could be of interest not only from an educational perspective (i.e. for graduate students), but also for researchers and medical professionals, to offer them fresh views on novel and powerful treatment strategies. We hope that the reader will find a broad spectrum of ideas and possibilities described in this book both interesting and convincing. Table of Contents: Introduction / The Heart: Structure, Cardiovascular Diseases, and Regeneration / Cell Sources for Cardiac Tissue Engineering / Biomaterials: Polymers, Scaffolds, and Basic Design Criteria / Biomaterials as Vehicles for Stem Cell Delivery and Retention in the Infarct / Bioengineering of Cardiac Patches, In Vitro / Perfusion Bioreactors and Stimulation Patterns in Cardiac T ssue Engineering / Vascularization of Cardiac Patches / Acellular Biomaterials for Cardiac Repair / Biomaterial-based Controlled Delivery of Bioactive Molecules for Myocardial Regeneration

• OLED Materials

  OLED performance is largely dependent upon OLED materials. This chapter describes the classification of OLED materials and typical OLED materials.OLED materials are divided into two types ??? vacuum evaporation type and solution type ??? from a process point of view. Vacuum evaporation materials are usually small molecular materials, while solution type materials contain polymers, dendrimers, and small molecular materials. In addition, materials are also divided into fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescent (TADF) materials in terms of emission mechanisms. From the function point of view, OLED materials can be classified as hole injection material, hole transport material, emission material, host material in emissive layer, electron transport material, electron injection material, charge blocking material, etc.Anode and cathode materials are also important, so this chapter also describes anode and cathode materials.In addition, this chapter describes molecular orientations of organic materials because this also influences OLED characteristics.