High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varghese, Tony; Hollar, Courtney; Richardson, Joseph

Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstratemore » a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm 2 with 60°C temperature difference between the hot side and cold side. In conclusion, the highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.« less

High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

DOE PAGES

Varghese, Tony; Hollar, Courtney; Richardson, Joseph; ...

2016-09-12

Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstratemore » a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm 2 with 60°C temperature difference between the hot side and cold side. In conclusion, the highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.« less

High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

PubMed Central

Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J.; Zhang, Yanliang

2016-01-01

Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications. PMID:27615036

DNA-nucleobases: Gate Dielectric/Passivation Layer for Flexible GFET-based Sensor Applications (Postprint)

DTIC Science & Technology

2015-09-24

kapton, Polydimethylsiloxane ( PDMS ), photo-print paper (laminate side) and Corning Willow glass (WG). Guanine was deposited onto graphene that had been...flexible substrates-kapton, PDMS , photo-print paper, and WG were performed to determine whether the graphene-substrate interface effects the graphene...flexible substrates-kapton, PDMS , photo-print paper, and WG. Kapton, PDMS , and photo-print paper were chosen as flexible substrates due to their

Synthesis of IGZO ink and study of ink-jet printed IGZO thin films with different Ga concentrations

NASA Astrophysics Data System (ADS)

Shen, Y. K.; Liu, Z.; Wang, X. L.; Ma, W. K.; Chen, Z. H.; Chen, T. P.; Zhang, H. Y.

2017-12-01

By dissolving gallium chloride (GaCl3), indium chloride (InCl3), zinc acetate dihydrate [Zn(OAc)2·2H2O] and monoethanolamine (MEA) into a solvent of 2-methoxyethanol, the IGZO ink was synthesized. Five types of IGZO ink were prepared with different molar ratios of In:Ga:Zn, which can be used for ink-jet printing process. The thermal behaviors of IGZO ink with different formulas were investigated and the ideal annealing temperature for film formation was found to be ∼450 °C. Based on the prepared ink, amorphous IGZO thin films were directly printed on the glass substrate with a FujiFilm Dimatix ink-jet printer, followed by a thermal annealing at 450 °C for 1 h. The surface morphology, crystal structure, optical transmittance, electron mobility and carrier concentration were characterized and investigated. The ink-jet printed amorphous IGZO thin films fabricated in this work can be used as switching medium in flexible resistive random access memory devices.

Apparatus And Method Of Using Flexible Printed Circuit Board In Optical Transceiver Device

DOEpatents

Anderson, Gene R.; Armendariz, Marcelino G.; Bryan, Robert P.; Carson, Richard F.; Duckett, III, Edwin B.; McCormick, Frederick B.; Peterson, David W.; Peterson, Gary D.; Reysen, Bill H.

2005-03-15

This invention relates to a flexible printed circuit board that is used in connection with an optical transmitter, receiver or transceiver module. In one embodiment, the flexible printed circuit board has flexible metal layers in between flexible insulating layers, and the circuit board comprises: (1) a main body region orientated in a first direction having at least one electrical or optoelectronic device; (2) a plurality of electrical contact pads integrated into the main body region, where the electrical contact pads function to connect the flexible printed circuit board to an external environment; (3) a buckle region extending from one end of the main body region; and (4) a head region extending from one end of the buckle region, and where the head region is orientated so that it is at an angle relative to the direction of the main body region. The electrical contact pads may be ball grid arrays, solder balls or land-grid arrays, and they function to connect the circuit board to an external environment. A driver or amplifier chip may be adapted to the head region of the flexible printed circuit board. In another embodiment, a heat spreader passes along a surface of the head region of the flexible printed circuit board, and a window is formed in the head region of the flexible printed circuit board. Optoelectronic devices are adapted to the head spreader in such a manner that they are accessible through the window in the flexible printed circuit board.

Foundations of mathematics and literacy: The role of executive functioning components.

PubMed

Purpura, David J; Schmitt, Sara A; Ganley, Colleen M

2017-01-01

The current study investigated the relations between the three cognitive processes that comprise executive functioning (EF)-response inhibition, working memory, and cognitive flexibility-and individual components of mathematics and literacy skills in preschool children. Participants were 125 preschool children ranging in age from 3.12 to 5.26years (M=4.17years, SD=0.58). Approximately 53.2% were female, and the sample was predominantly Caucasian (69.8%). Results suggest that the components of EF may be differentially related to the specific components of early mathematics and literacy. For mathematics, response inhibition was broadly related to most components. Working memory was related to more advanced mathematics skills that involve comparison or combination of numbers and quantities. Cognitive flexibility was related to more conceptual or abstract mathematics skills. For early literacy, response inhibition and cognitive flexibility were related to print knowledge, and working memory was related only to phonological awareness. None of the EF components was related to vocabulary. These findings provide initial evidence for better understanding the ways in which EF components and academic skills are related and measured. Furthermore, the findings provide a foundation for further study of the components of each domain using a broader and more diverse array of measures. Copyright © 2016 Elsevier Inc. All rights reserved.

A 3D Printed Implantable Device for Voiding the Bladder Using Shape Memory Alloy (SMA) Actuators.

PubMed

Hassani, Faezeh Arab; Peh, Wendy Yen Xian; Gammad, Gil Gerald Lasam; Mogan, Roshini Priya; Ng, Tze Kiat; Kuo, Tricia Li Chuen; Ng, Lay Guat; Luu, Percy; Yen, Shih-Cheng; Lee, Chengkuo

2017-11-01

Underactive bladder or detrusor underactivity (DU) is defined as a reduction of contraction strength or duration of the bladder wall. Despite the serious healthcare implications of DU, there are limited solutions for affected individuals. A flexible 3D printed implantable device driven by shape memory alloys (SMA) actuators is presented here for the first time to physically contract the bladder to restore voluntary control of the bladder for individuals suffering from DU. This approach is used initially in benchtop experiments with a rubber balloon acting as a model for the rat bladder to verify its potential for voiding, and that the operating temperatures are safe for the eventual implantation of the device in a rat. The device is then implanted and tested on an anesthetized rat, and a voiding volume of more than 8% is successfully achieved for the SMA-based device without any surgical intervention or drug injection to relax the external sphincter.

Electrohydrodynamic printing of silver nanowires for flexible and stretchable electronics.

PubMed

Cui, Zheng; Han, Yiwei; Huang, Qijin; Dong, Jingyan; Zhu, Yong

2018-04-19

A silver nanowire (AgNW) based conductor is a promising component for flexible and stretchable electronics. A wide range of flexible/stretchable devices using AgNW conductors has been demonstrated recently. High-resolution, high-throughput printing of AgNWs remains a critical challenge. Electrohydrodynamic (EHD) printing has been developed as a promising technique to print different materials on a variety of substrates with high resolution. Here, AgNW ink was developed for EHD printing. The printed features can be controlled by several parameters including AgNW concentration, ink viscosity, printing speed, stand-off distance, etc. With this method, AgNW patterns can be printed on a range of substrates, e.g. paper, polyethylene terephthalate (PET), glass, polydimethylsiloxane (PDMS), etc. First, AgNW samples on PDMS were characterized under bending and stretching. Then AgNW heaters and electrocardiogram (ECG) electrodes were fabricated to demonstrate the potential of this printing technique for AgNW-based flexible and stretchable devices.

Concept for a 3D-printed soft rotary actuator driven by a shape-memory alloy

NASA Astrophysics Data System (ADS)

Yuan, Han; Chapelle, Frédéric; Fauroux, Jean-Christophe; Balandraud, Xavier

2018-05-01

In line with the recent development of soft actuators involving shape-memory alloys (SMAs) embedded in compliant structures, this paper proposes a concept for a rotary actuator driven by a SMA wire placed inside a 3D-printed helical structure. The concept consists of using the one-way memory effect of the SMA (activated by Joule heating) to create the rotation of a material point of the structure, while the inverse rotation is obtained during the return to ambient temperature thanks to the structure’s elasticity. The study was performed in three steps. First, a prototype was designed from a chain of design rules, and tested to validate the feasibility of the concept. Thermal and geometrical measurements were performed using infrared and visible-range stereo cameras. A clockwise rotation (250°) followed by an anti-clockwise rotation (‑200°) were obtained, enabling us to validate the concept despite the partial reversibility of the movement. Second, finite element simulations were performed to improve rotation reversibility. The high compliance of the mechanical system required a framework of large displacements for the calculations (in the strength of materials sense), due to the high structural flexibility. Finally, a second prototype was constructed and tested. Attention was paid to the rotation (fully reversible rotation of 150° reached) as well as to parasitic movements due to overall structural deformation. This study opens new prospects for the design and analysis of 3D-printed soft actuators activated by smart materials.

Chemically programmed ink-jet printed resistive WORM memory array and readout circuit

NASA Astrophysics Data System (ADS)

Andersson, H.; Manuilskiy, A.; Sidén, J.; Gao, J.; Hummelgård, M.; Kunninmel, G. V.; Nilsson, H.-E.

2014-09-01

In this paper an ink-jet printed write once read many (WORM) resistive memory fabricated on paper substrate is presented. The memory elements are programmed for different resistance states by printing triethylene glycol monoethyl ether on the substrate before the actual memory element is printed using silver nano particle ink. The resistance is thus able to be set to a broad range of values without changing the geometry of the elements. A memory card consisting of 16 elements is manufactured for which the elements are each programmed to one of four defined logic levels, providing a total of 4294 967 296 unique possible combinations. Using a readout circuit, originally developed for resistive sensors to avoid crosstalk between elements, a memory card reader is manufactured that is able to read the values of the memory card and transfer the data to a PC. Such printed memory cards can be used in various applications.

Printable Transparent Conductive Films for Flexible Electronics.

PubMed

Li, Dongdong; Lai, Wen-Yong; Zhang, Yi-Zhou; Huang, Wei

2018-03-01

Printed electronics are an important enabling technology for the development of low-cost, large-area, and flexible optoelectronic devices. Transparent conductive films (TCFs) made from solution-processable transparent conductive materials, such as metal nanoparticles/nanowires, carbon nanotubes, graphene, and conductive polymers, can simultaneously exhibit high mechanical flexibility, low cost, and better photoelectric properties compared to the commonly used sputtered indium-tin-oxide-based TCFs, and are thus receiving great attention. This Review summarizes recent advances of large-area flexible TCFs enabled by several roll-to-roll-compatible printed techniques including inkjet printing, screen printing, offset printing, and gravure printing using the emerging transparent conductive materials. The preparation of TCFs including ink formulation, substrate treatment, patterning, and postprocessing, and their potential applications in solar cells, organic light-emitting diodes, and touch panels are discussed in detail. The rational combination of a variety of printed techniques with emerging transparent conductive materials is believed to extend the opportunities for the development of printed electronics within the realm of flexible electronics and beyond. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasma jet printing for flexible substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gandhiraman, Ram P.; Singh, Eric; Diaz-Cartagena, Diana C.

2016-03-21

Recent interest in flexible electronics and wearable devices has created a demand for fast and highly repeatable printing processes suitable for device manufacturing. Robust printing technology is critical for the integration of sensors and other devices on flexible substrates such as paper and textile. An atmospheric pressure plasma-based printing process has been developed to deposit different types of nanomaterials on flexible substrates. Multiwalled carbon nanotubes were deposited on paper to demonstrate site-selective deposition as well as direct printing without any type of patterning. Plasma-printed nanotubes were compared with non-plasma-printed samples under similar gas flow and other experimental conditions and foundmore » to be denser with higher conductivity. The utility of the nanotubes on the paper substrate as a biosensor and chemical sensor was demonstrated by the detection of dopamine, a neurotransmitter, and ammonia, respectively.« less

Integrated digital printing of flexible circuits for wireless sensing (Conference Presentation)

NASA Astrophysics Data System (ADS)

Mei, Ping; Whiting, Gregory L.; Schwartz, David E.; Ng, Tse Nga; Krusor, Brent S.; Ready, Steve E.; Daniel, George; Veres, Janos; Street, Bob

2016-09-01

Wireless sensing has broad applications in a wide variety of fields such as infrastructure monitoring, chemistry, environmental engineering and cold supply chain management. Further development of sensing systems will focus on achieving light weight, flexibility, low power consumption and low cost. Fully printed electronics provide excellent flexibility and customizability, as well as the potential for low cost and large area applications, but lack solutions for high-density, high-performance circuitry. Conventional electronics mounted on flexible printed circuit boards provide high performance but are not digitally fabricated or readily customizable. Incorporation of small silicon dies or packaged chips into a printed platform enables high performance without compromising flexibility or cost. At PARC, we combine high functionality c-Si CMOS and digitally printed components and interconnects to create an integrated platform that can read and process multiple discrete sensors. Our approach facilitates customization to a wide variety of sensors and user interfaces suitable for a broad range of applications including remote monitoring of health, structures and environment. This talk will describe several examples of printed wireless sensing systems. The technologies required for these sensor systems are a mix of novel sensors, printing processes, conventional microchips, flexible substrates and energy harvesting power solutions.

Synthesis of crystalline gels on a light-induced polymerization 3D printer (Conference Presentation)

NASA Astrophysics Data System (ADS)

Gong, Jin; Mao, Yuchen; Miyazaki, Takuya; Zhu, Meifang

2017-04-01

3D printing, also knows as Additive Manufacturing (AM), was first commercialized in 1986, and has been growing at breakneck speed since 2009 when Stratasys' key patent expired. Currently the 3D printing machines coming on the market can be broadly classified into three categories from the material state point of view: plastic filament printers, powder (or pellet) printers, film printers and liquid photopolymer printers. Much of the work in our laboratory revolves around the crystalline gels. We have succeeded in developing them with high toughness, high flexibility, particularly with many functions as shape memory, energy storage, freshness-retaining, water-absorbing, etc. These crystalline gels are synthesized by light-induced radical polymerization that involves light-reactive monomer having the property of curing with light of a sufficient energy to drive the reaction from liquid to solid. Note that the light-induced polymerized 3D printing uses the same principle. To open up the possibilities for broader application of our crystalline functional gels, we are interested in making them available for 3D printing. In this paper, we share the results of our latest research on the 3D printing of crystalline gels on light-induced 3D printers.

Experimental Demonstration of Printed Graphene Nano-flakes Enabled Flexible and Conformable Wideband Radar Absorbers.

PubMed

Huang, Xianjun; Pan, Kewen; Hu, Zhirun

2016-12-07

In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8-12 GHz) and Ku (12-18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene's application to practical RCS reductions.

Gravure printing of graphene for large-area flexible electronics.

PubMed

Secor, Ethan B; Lim, Sooman; Zhang, Heng; Frisbie, C Daniel; Francis, Lorraine F; Hersam, Mark C

2014-07-09

Gravure printing of graphene is demonstrated for the rapid production of conductive patterns on flexible substrates. Development of suitable inks and printing parameters enables the fabrication of patterns with a resolution down to 30 μm. A mild annealing step yields conductive lines with high reliability and uniformity, providing an efficient method for the integration of graphene into large-area printed and flexible electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The flexibility controlling study for 3D printed splint

NASA Astrophysics Data System (ADS)

Li, Jianyou; Tanaka, Hiroya

2017-04-01

The 3D printed splint's light weight, ventilation and water proof are considered as significant improvement for patients' comfortableness. Somehow, the flexible material is required in the splint to avoid skin friction may cased by its rigid edge, but this would increase the complexity and timeconsuming. In this study, two main techniques to control the infilling densities and printing temperature are applied on printing splint prototype. The gradual increasing of infilling density from splint outside to inside would turn the partial strength from hard to flexible. Besides, higher printing temperature can also achieve stronger hardness after cooling. Such structural can provide high strength in outside surface to keep the immovable function, and give flexible touch of inside surface to decrease friction on the patient's skin.

Self-expanding/shrinking structures by 4D printing

NASA Astrophysics Data System (ADS)

Bodaghi, M.; Damanpack, A. R.; Liao, W. H.

2016-10-01

The aim of this paper is to create adaptive structures capable of self-expanding and self-shrinking by means of four-dimensional printing technology. An actuator unit is designed and fabricated directly by printing fibers of shape memory polymers (SMPs) in flexible beams with different arrangements. Experiments are conducted to determine thermo-mechanical material properties of the fabricated part revealing that the printing process introduced a strong anisotropy into the printed parts. The feasibility of the actuator unit with self-expanding and self-shrinking features is demonstrated experimentally. A phenomenological constitutive model together with analytical closed-form solutions are developed to replicate thermo-mechanical behaviors of SMPs. Governing equations of equilibrium are developed for printed structures based on the non-linear Green-Lagrange strain tensor and solved implementing a finite element method along with an iterative incremental Newton-Raphson scheme. The material-structural model is then applied to digitally design and print SMP adaptive lattices in planar and tubular shapes comprising a periodic arrangement of SMP actuator units that expand and then recover their original shape automatically. Numerical and experimental results reveal that the proposed planar lattice as meta-materials can be employed for plane actuators with self-expanding/shrinking features or as structural switches providing two different dynamic characteristics. It is also shown that the proposed tubular lattice with a self-expanding/shrinking mechanism can serve as tubular stents and grippers for bio-medical or piping applications.

Screen printed UHF antennas on flexible substrates

NASA Astrophysics Data System (ADS)

Janeczek, Kamil; Młożniak, Anna; Kozioł, Grażyna; Araźna, Aneta; Jakubowska, Małgorzata; Bajurko, Paweł

2010-09-01

Printed electronics belongs to the most important developing electronics technologies. It provides new possibilities to produce low cost and large area devices. In its range several applications can be distinguished like printed batteries, OLED, biosensors, photovoltaic cells or RFID tags. In the presented investigation, antennas working in UHF frequency range were elaborated. It can be applied in the future for flexible RFID tags. To produce these antennas polymer paste with silver flakes was used. It was deposited on two flexible substrates (foil and photo paper) with screen printing techniques. After printing process surface profile, electrical and microwave parameters of performed antennas were measured using digital multimeter and network analyzer, relatively. Furthermore, a thickness of printed layers was measured.

Impact of pulse thermal processing on the properties of inkjet printed metal and flexible sensors

DOE PAGES

Joshi, Pooran C.; Kuruganti, Teja; Killough, Stephen M.

2015-03-11

In this paper, we report on the low temperature processing of environmental sensors employing pulse thermal processing (PTP) technique to define a path toward flexible sensor technology on plastic, paper, and fabric substrates. Inkjet printing and pulse thermal processing technique were used to realize mask-less, additive integration of low-cost sensors on polymeric substrates with specific focus on temperature, humidity, and strain sensors. The printed metal line performance was evaluated in terms of the electrical conductivity characteristics as a function of post-deposition thermal processing conditions. The PTP processed Ag metal lines exhibited high conductivity with metal sheet resistance values below 100more » mΩ/{whitesquare} using a pulse width as short as 250 μs. The flexible temperature and relative humidity sensors were defined on flexible polyimide substrates by direct printing of Ag metal structures. The printed resistive temperature sensor and capacitive humidity sensor were characterized for their sensitivity with focus on future smart-building applications. Strain gauges were printed on polyimide substrate to determine the mechanical properties of the silver nanoparticle films. Finally, the observed electrical properties of the printed metal lines and the sensitivity of the flexible sensors show promise for the realization of a high performance print-on-demand technology exploiting low thermal-budget PTP technique.« less

Screen printing as a scalable and low-cost approach for rigid and flexible thin-film transistors using separated carbon nanotubes.

PubMed

Cao, Xuan; Chen, Haitian; Gu, Xiaofei; Liu, Bilu; Wang, Wenli; Cao, Yu; Wu, Fanqi; Zhou, Chongwu

2014-12-23

Semiconducting single-wall carbon nanotubes are very promising materials in printed electronics due to their excellent mechanical and electrical property, outstanding printability, and great potential for flexible electronics. Nonetheless, developing scalable and low-cost approaches for manufacturing fully printed high-performance single-wall carbon nanotube thin-film transistors remains a major challenge. Here we report that screen printing, which is a simple, scalable, and cost-effective technique, can be used to produce both rigid and flexible thin-film transistors using separated single-wall carbon nanotubes. Our fully printed top-gated nanotube thin-film transistors on rigid and flexible substrates exhibit decent performance, with mobility up to 7.67 cm2 V(-1) s(-1), on/off ratio of 10(4)∼10(5), minimal hysteresis, and low operation voltage (<10 V). In addition, outstanding mechanical flexibility of printed nanotube thin-film transistors (bent with radius of curvature down to 3 mm) and driving capability for organic light-emitting diode have been demonstrated. Given the high performance of the fully screen-printed single-wall carbon nanotube thin-film transistors, we believe screen printing stands as a low-cost, scalable, and reliable approach to manufacture high-performance nanotube thin-film transistors for application in display electronics. Moreover, this technique may be used to fabricate thin-film transistors based on other materials for large-area flexible macroelectronics, and low-cost display electronics.

Experimental Demonstration of Printed Graphene Nano-flakes Enabled Flexible and Conformable Wideband Radar Absorbers

PubMed Central

Huang, Xianjun; Pan, Kewen; Hu, Zhirun

2016-01-01

In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8–12 GHz) and Ku (12–18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene’s application to practical RCS reductions. PMID:27924823

Soft tissue models: easy and inexpensive flexible 3D printing as a help in surgical planning of cardiovascular disorders

NASA Astrophysics Data System (ADS)

Starosolski, Zbigniew; Ezon, David S.; Krishnamurthy, Rajesh; Dodd, Nicholas; Heinle, Jeffrey; Mckenzie, Dean E.; Annapragada, Ananth

2017-03-01

We developed a technology that allows a simple desktop 3D printer with dual extruder to fabricate 3D flexible models of Major AortoPulmonary Collateral Arteries. The study was designed to assess whether the flexible 3D printed models could help during surgical planning phase. Simple FDM 3D printers are inexpensive, versatile in use and easy to maintain, but complications arise when the designed model is complex and has tubular structures with small diameter less than 2mm. The advantages of FDM printers are cost and simplicity of use. We use precisely selected materials to overcome the obstacles listed above. Dual extruder allows to use two different materials while printing, which is especially important in the case of fragile structures like pulmonary vessels and its supporting structures. The latter should not be removed by hand to avoid a truncation of the model. We utilize the water soluble PVA as a supporting structure and Poro-Lay filament for flexible model of AortoPulmonary collateral arteries. Poro-Lay filament is different as compared to all the other flexible ones like polymer-based. Poro-Lay is rigid while printing and this allows printing of structures small in diameter. It achieves flexibility after washing out of printed model with water. It becomes soft in touch and gelatinous. Using both PVA and Poro-Lay gives a huge advantage allowing to wash out the supporting structures and achieve flexibility in one washing operation, saving time and avoiding human error with cleaning the model. We evaluated 6 models for MAPCAS surgical planning study. This approach is also cost-effective - an average cost of materials for print is less than $15; models are printed in facility without any delays. Flexibility of 3D printed models approximate soft tissues properly, mimicking Aortopulmonary collateral arteries. Second utilization models has educational value for both residents and patients' family. Simplification of 3D flexible process could help in other models of soft tissue pathologies like aneurysms, ventricular septal defects and other vascular anomalies.

Direct Desktop Printed-Circuits-on-Paper Flexible Electronics

PubMed Central

Zheng, Yi; He, Zhizhu; Gao, Yunxia; Liu, Jing

2013-01-01

There currently lacks of a way to directly write out electronics, just like printing pictures on paper by an office printer. Here we show a desktop printing of flexible circuits on paper via developing liquid metal ink and related working mechanisms. Through modifying adhesion of the ink, overcoming its high surface tension by dispensing machine and designing a brush like porous pinhead for printing alloy and identifying matched substrate materials among different papers, the slightly oxidized alloy ink was demonstrated to be flexibly printed on coated paper, which could compose various functional electronics and the concept of Printed-Circuits-on-Paper was thus presented. Further, RTV silicone rubber was adopted as isolating inks and packaging material to guarantee the functional stability of the circuit, which suggests an approach for printing 3D hybrid electro-mechanical device. The present work paved the way for a low cost and easygoing method in directly printing paper electronics.

Aerosol jet printed silver nanowire transparent electrode for flexible electronic application

NASA Astrophysics Data System (ADS)

Tu, Li; Yuan, Sijian; Zhang, Huotian; Wang, Pengfei; Cui, Xiaolei; Wang, Jiao; Zhan, Yi-Qiang; Zheng, Li-Rong

2018-05-01

Aerosol jet printing technology enables fine feature deposition of electronic materials onto low-temperature, non-planar substrates without masks. In this work, silver nanowires (AgNWs) are proposed to be printed into transparent flexible electrodes using a Maskless Mesoscale Material Deposition Aerosol Jet® printing system on a glass substrate. The influence of the most significant process parameters, including printing cycles, printing speed, and nozzle size, on the performance of AgNW electrodes was systematically studied. The morphologies of printed patterns were characterized by scanning electron microscopy, and the transmittance was evaluated using an ultraviolet-visible spectrophotometer. Under optimum conditions, high transparent AgNW electrodes with a sheet resistance of 57.68 Ω/sq and a linewidth of 50.9 μm were obtained, which is an important step towards a higher performance goal for flexible electronic applications.

Direct Write Printing on Thin and Flexible Substrates for Space Applications

NASA Technical Reports Server (NTRS)

Paquette, Beth

2016-01-01

This presentation describes the work done on direct-write printing conductive traces for a flexible detector application. A Repeatability Plan was established to define detector requirements, material and printer selections, printing facilities, and tests to verify requirements are met. Designs were created for the detector, and printed using an aerosol jet printer. Testing for requirement verification is ongoing.

Plasma jet printing of electronic materials on flexible and nonconformal objects.

PubMed

Gandhiraman, Ram P; Jayan, Vivek; Han, Jin-Woo; Chen, Bin; Koehne, Jessica E; Meyyappan, M

2014-12-10

We present a novel approach for the room-temperature fabrication of conductive traces and their subsequent site-selective dielectric encapsulation for use in flexible electronics. We have developed an aerosol-assisted atmospheric pressure plasma-based deposition process for efficiently depositing materials on flexible substrates. Silver nanowire conductive traces and silicon dioxide dielectric coatings for encapsulation were deposited using this approach as a demonstration. The paper substrate with silver nanowires exhibited a very low change in resistance upon 50 cycles of systematic deformation, exhibiting high mechanical flexibility. The applicability of this process to print conductive traces on nonconformal 3D objects was also demonstrated through deposition on a 3D-printed thermoplastic object, indicating the potential to combine plasma printing with 3D printing technology. The role of plasma here includes activation of the material present in the aerosol for deposition, increasing the deposition rate, and plasma polymerization in the case of inorganic coatings. The demonstration here establishes a low-cost, high-throughput, and facile process for printing electronic components on nonconventional platforms.

Metal Oxide Thin Film Transistors on Paper Substrate: Fabrication, Characterization, and Printing Process

NASA Astrophysics Data System (ADS)

Choi, Nack-Bong

Flexible electronics is an emerging next-generation technology that offers many advantages such as light weight, durability, comfort, and flexibility. These unique features enable many new applications such as flexible display, flexible sensors, conformable electronics, and so forth. For decades, a variety of flexible substrates have been demonstrated for the application of flexible electronics. Most of them are plastic films and metal foils so far. For the fundamental device of flexible circuits, thin film transistors (TFTs) using poly silicon, amorphous silicon, metal oxide and organic semiconductor have been successfully demonstrated. Depending on application, low-cost and disposable flexible electronics will be required for convenience. Therefore it is important to study inexpensive substrates and to explore simple processes such as printing technology. In this thesis, paper is introduced as a new possible substrate for flexible electronics due to its low-cost and renewable property, and amorphous indium gallium zinc oxide (a-IGZO) TFTs are realized as the promising device on the paper substrate. The fabrication process and characterization of a-IGZO TFT on the paper substrate are discussed. a-IGZO TFTs using a polymer gate dielectric on the paper substrate demonstrate excellent performances with field effect mobility of ˜20 cm2 V-1 s-1, on/off current ratio of ˜106, and low leakage current, which show the enormous potential for flexible electronics application. In order to complement the n-channel a-IGZO TFTs and then enable complementary metal-oxide semiconductor (CMOS) circuit architectures, cuprous oxide is studied as a candidate material of p-channel oxide TFTs. In this thesis, a printing process is investigated as an alternative method for the fabrication of low-cost and disposable electronics. Among several printing methods, a modified offset roll printing that prints high resolution patterns is presented. A new method to fabricate a high resolution printing plate is investigated and the most favorable condition to transfer ink from a blanket to a cliche is studied. Consequently, a high resolution cliche is demonstrated and the printed patterns of 10mum width and 6mum line spacing are presented. In addition, the top gate a-IGZO TFTs with channel width/length of 12/6mum is successfully demonstrated by printing etch-resists. This work validates the compatibility of a-IGZO TFT on paper substrate for the disposable microelectronics application and presents the potential of low-cost and high resolution printing technology.

Aerosol-jet printing of nanowire networks of zinc octaethylporphyrin and its application in flexible photodetectors.

PubMed

Wang, Feng-Xia; Lin, Jian; Gu, Wei-Bing; Liu, Yong-Qiang; Wu, Hao-Di; Pan, Ge-Bo

2013-03-25

Nanowire networks of zinc octaethylporphyrin (ZnOEP) were printed using an aerosol-jet printer on a poly(ethylene terephthalate) (PET) flexible substrate. The prototype photodetector based on the as-printed network exhibited high photosensitivity, fast photoresponse, and excellent mechanical stability.

Facile synthesis of amorphous FeOOH/MnO2 composites as screen-printed electrode materials for all-printed solid-state flexible supercapacitors

NASA Astrophysics Data System (ADS)

Lu, Qiang; Liu, Li; Yang, Shuanglei; Liu, Jun; Tian, Qingyong; Yao, Weijing; Xue, Qingwen; Li, Mengxiao; Wu, Wei

2017-09-01

More convenience and intelligence life lead by flexible/wearable electronics requires innovation and hommization of power sources. Here, amorphous FeOOH/MnO2 composite as screen-printed electrode materials for supercapacitors (SCs) is synthesized by a facile method, and solid-state flexible SCs with aesthetic design are fabricated by fully screen-printed process on different substrates, including PET, paper and textile. The amorphous FeOOH/MnO2 composite shows a high specific capacitance and a good rate capability (350.2 F g-1 at a current density of 0.5 A g-1 and 159.5 F g-1 at 20 A g-1). It also possesses 95.6% capacitance retention even after 10 000 cycles. Moreover, the all-printed solid-state flexible SC device exhibits a high area specific capacitance of 5.7 mF cm-2 and 80% capacitance retention even after 2000 cycles. It also shows high mechanical flexibility. Simultaneously, these printed SCs on different substrates in series are capable to light up a 1.9 V yellow light emitting diode (LED), even after bending and stretching.

75 FR 59086 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-27

... package printing entitled ``Control Techniques Guidelines for Flexible Package Printing'' (Publication No... adoption of the EPA CTG for flexible packaging printing. EPA develops CTGs as guidance on control... Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control Techniques Guidelines for...

Performance Evaluation of Strain Gauge Printed Using Automatic Fluid Dispensing System on Conformal Substrates

NASA Astrophysics Data System (ADS)

Khairilhijra Khirotdin, Rd.; Faridzuan Ngadiron, Mohamad; Adzeem Mahadzir, Muhammad; Hassan, Nurhafizzah

2017-08-01

Smart textiles require flexible electronics that can withstand daily stresses like bends and stretches. Printing using conductive inks provides the flexibility required but the current printing techniques suffered from ink incompatibility, limited of substrates to be printed with and incompatible with conformal substrates due to its rigidity and low flexibility. An alternate printing technique via automatic fluid dispensing system is proposed and its performances on printing strain gauge on conformal substrates were evaluated to determine its feasibility. Process parameters studied including printing speed, deposition height, curing time and curing temperature. It was found that the strain gauge is proven functional as expected since different strains were induced when bent on variation of bending angles and curvature radiuses from designated bending fixtures. The average change of resistances were doubled before the strain gauge starts to break. Printed strain gauges also exhibited some excellence elasticity as they were able to resist bending up to 70° angle and 3 mm of curvature radius.

Printable inorganic nanomaterials for flexible transparent electrodes: from synthesis to application

NASA Astrophysics Data System (ADS)

Wang, Dingrun; Mei, Yongfeng; Huang, Gaoshan

2018-01-01

Printed and flexible electronics are definitely promising cutting-edge electronic technologies of the future. They offer a wide-variety of applications such as flexible circuits, flexible displays, flexible solar cells, skin-like pressure sensors, and radio frequency identification tags in our daily life. As the most-fundamental component of electronics, electrodes are made of conductive materials that play a key role in flexible and printed electronic devices. In this review, various inorganic conductive materials and strategies for obtaining highly conductive and uniform electrodes are demonstrated. Applications of printed electrodes fabricated via these strategies are also described. Nevertheless, there are a number of challenges yet to overcome to optimize the processing and performance of printed electrodes. Project supported by the National Natural Science Foundation of China (Nos. 51475093, U1632115), the Science and Technology Commission of Shanghai Municipality (No. 14JC1400200), the National Key Technologies R&D Program of China (No. 2015ZX02102-003), and the Changjiang Young Scholars Programme of China.

Fully Screen-Printed, Large-Area, and Flexible Active-Matrix Electrochromic Displays Using Carbon Nanotube Thin-Film Transistors.

PubMed

Cao, Xuan; Lau, Christian; Liu, Yihang; Wu, Fanqi; Gui, Hui; Liu, Qingzhou; Ma, Yuqiang; Wan, Haochuan; Amer, Moh R; Zhou, Chongwu

2016-11-22

Semiconducting single-wall carbon nanotubes are ideal semiconductors for printed electronics due to their advantageous electrical and mechanical properties, intrinsic printability in solution, and desirable stability in air. However, fully printed, large-area, high-performance, and flexible carbon nanotube active-matrix backplanes are still difficult to realize for future displays and sensing applications. Here, we report fully screen-printed active-matrix electrochromic displays employing carbon nanotube thin-film transistors. Our fully printed backplane shows high electrical performance with mobility of 3.92 ± 1.08 cm 2 V -1 s -1 , on-off current ratio I on /I off ∼ 10 4 , and good uniformity. The printed backplane was then monolithically integrated with an array of printed electrochromic pixels, resulting in an entirely screen-printed active-matrix electrochromic display (AMECD) with good switching characteristics, facile manufacturing, and long-term stability. Overall, our fully screen-printed AMECD is promising for the mass production of large-area and low-cost flexible displays for applications such as disposable tags, medical electronics, and smart home appliances.

All-Printed Flexible and Stretchable Electronics.

PubMed

Mohammed, Mohammed G; Kramer, Rebecca

2017-05-01

A fully automated additive manufacturing process that produces all-printed flexible and stretchable electronics is demonstrated. The printing process combines soft silicone elastomer printing and liquid metal processing on a single high-precision 3D stage. The platform is capable of fabricating extremely complex conductive circuits, strain and pressure sensors, stretchable wires, and wearable circuits with high yield and repeatability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Layered memristive and memcapacitive switches for printable electronics

NASA Astrophysics Data System (ADS)

Bessonov, Alexander A.; Kirikova, Marina N.; Petukhov, Dmitrii I.; Allen, Mark; Ryhänen, Tapani; Bailey, Marc J. A.

2015-02-01

Novel computing technologies that imitate the principles of biological neural systems may offer low power consumption along with distinct cognitive and learning advantages. The development of reliable memristive devices capable of storing multiple states of information has opened up new applications such as neuromorphic circuits and adaptive systems. At the same time, the explosive growth of the printed electronics industry has expedited the search for advanced memory materials suitable for manufacturing flexible devices. Here, we demonstrate that solution-processed MoOx/MoS2 and WOx/WS2 heterostructures sandwiched between two printed silver electrodes exhibit an unprecedentedly large and tunable electrical resistance range from 102 to 108 Ω combined with low programming voltages of 0.1-0.2 V. The bipolar resistive switching, with a concurrent capacitive contribution, is governed by an ultrathin (<3 nm) oxide layer. With strong nonlinearity in switching dynamics, different mechanisms of synaptic plasticity are implemented by applying a sequence of electrical pulses.

All dispenser printed flexible 3D structured thermoelectric generators

NASA Astrophysics Data System (ADS)

Cao, Z.; Shi, J. J.; Torah, R. N.; Tudor, M. J.; Beeby, S. P.

2015-12-01

This work presents a vertically fabricated 3D thermoelectric generator (TEG) by dispenser printing on flexible polyimide substrate. This direct-write technology only involves printing of electrodes, thermoelectric active materials and structure material, which needs no masks to transfer the patterns onto the substrate. The dimension for single thermoelectric element is 2 mm × 2 mm × 0.5 mm while the distance between adjacent cubes is 1.2 mm. The polymer structure layer was used to support the electrodes which are printed to connect the top ends of the thermoelectric material and ensure the flexibility as well. The advantages and the limitations of the dispenser printed 3D TEGs will also be evaluated in this paper. The proposed method is potential to be a low-cost and scalable fabrication solution for TEGs.

Screen printed passive components for flexible power electronics

NASA Astrophysics Data System (ADS)

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-10-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Screen printed passive components for flexible power electronics

PubMed Central

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-01-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application. PMID:26514331

Screen printed passive components for flexible power electronics.

PubMed

Ostfeld, Aminy E; Deckman, Igal; Gaikwad, Abhinav M; Lochner, Claire M; Arias, Ana C

2015-10-30

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components-inductors, capacitors, and resistors-perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Low-Cost Inkjet Printing Technology for the Rapid Prototyping of Transducers

PubMed Central

Andò, Bruno; Baglio, Salvatore; Bulsara, Adi R.; Emery, Teresa; Marletta, Vincenzo; Pistorio, Antonio

2017-01-01

Recently, there has been an upsurge in efforts dedicated to developing low-cost flexible electronics by exploiting innovative materials and direct printing technologies. This interest is motivated by the need for low-cost mass-production, shapeable, and disposable devices, and the rapid prototyping of electronics and sensors. This review, following a short overview of main printing processes, reports examples of the development of flexible transducers through low-cost inkjet printing technology. PMID:28368318

Flexible Thick-Film Electrochemical Sensors: Impact of Mechanical Bending and Stress on the Electrochemical Behavior

PubMed Central

Cai, Jiaying; Cizek, Karel; Long, Brenton; McAferty, Kenyon; Campbell, Casey G.; Allee, David R.; Vogt, Bryan D.; La Belle, Jeff; Wang, Joseph

2009-01-01

The influence of the mechanical bending, rolling and crimping of flexible screen-printed electrodes upon their electrical properties and electrochemical behavior has been elucidated. Three different flexible plastic substrates, Mylar, polyethylene naphthalate (PEN), and Kapton, have been tested in connection to the printing of graphite ink working electrodes. Our data indicate that flexible printed electrodes can be bent to extremely small radii of curvature and still function well, despite a marginal increase the electrical resistance. Below critical radii of curvature of ~8 mm, full recovery of the electrical resistance occurs upon strain release. The electrochemical response is maintained for sub-mm bending radii and a 180° pinch of the electrode does not lead to device failure. The electrodes appear to be resistant to repeated bending. Such capabilities are demonstrated using model compounds, including ferrocyanide, trinitrotoluene (TNT) and nitronaphthalene (NN). These printed electrodes hold great promise for widespread applications requiring flexible, yet robust non-planar sensing devices. PMID:20160861

A screen-printed flexible flow sensor

NASA Astrophysics Data System (ADS)

Moschos, A.; Syrovy, T.; Syrova, L.; Kaltsas, G.

2017-04-01

A thermal flow sensor was printed on a flexible plastic substrate using exclusively screen-printing techniques. The presented device was implemented with custom made screen-printed thermistors, which allows simple, cost-efficient production on a variety of flexible substrates while maintaining the typical advantages of thermal flow sensors. Evaluation was performed for both static (zero flow) and dynamic conditions using a combination of electrical measurements and IR imaging techniques in order to determine important characteristics, such as temperature response, output repeatability, etc. The flow sensor was characterized utilizing the hot-wire and calorimetric principles of operation, while the preliminary results appear to be very promising, since the sensor was successfully evaluated and displayed adequate sensitivity in a relatively wide flow range.

Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system.

PubMed

Chang, Jaehyuk; Lee, Sunggun; Lee, Ki Beom; Lee, Seungjun; Cho, Young Tae; Seo, Jungwoo; Lee, Sukwon; Jo, Gugrae; Lee, Ki-yong; Kong, Hyang-Shik; Kwon, Sin

2015-05-01

For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.

3D Printing of a Thermoplastic Shape Memory Polymer using FDM

NASA Astrophysics Data System (ADS)

Zhao, Zhiyang; Weiss, R. A.; Vogt, Bryan

Shape memory polymers (SMPs) change from a temporary shape to its permanent shape when exposed to an external stimulus. The shape memory relies on the presence of two independent networks. 3D printing provides a facile method to fabricate complex shapes with high degrees of customizability. The most common consumer 3D printing technology is fused deposition modeling (FDM), which relies on the extrusion of a thermoplastic filament to build-up the part in a layer by layer fashion. The material choices for FDM are limited, but growing. The generation of an SMP that is printable by FDM could open SMPs to many new potential applications. In this work, we demonstrate printing of thermally activated SMP using FDM. Partially neutralized poly(ethylene-co-r-methacrylic acid) ionomers (Surlyn by Dupont) was extruded into filaments and used as a model thermoplastic shape memory material. The properties of the SMP part can be readily tuned by print parameters, such as infill density or infill direction without changing the base material. We discuss the performance and characteristics of 3D printed shapes compared to their compression molded analogs.

EDITORIAL: Nanotechnology-based flexible electronics Nanotechnology-based flexible electronics

NASA Astrophysics Data System (ADS)

Subramanian, Vivek; Lee, Takhee

2012-08-01

Research on flexible electronics has grown exponentially over the last decade. Researchers around the globe are developing a wide range of flexible systems, including displays [1, 2], sensors [3-5], RFID tags [6, 7] and other similar devices [8]. Innovations in materials have been key to the increased research success in this field of research in recent years [9]. Transistors, interconnects, memory cells, passive components and other assorted devices all have challenging material demands for flexible electronics to become a reality. Nanomaterials of various kinds have been found to represent a tremendously powerful tool, with nanoparticles [10], nanotubes, nanowires [3, 11] and engineered organic molecules [12, 13] contributing to the realization of high-performance semiconductors, dielectrics and conductors for flexible electronics applications. Nanomaterials offer tunability in terms of performance, solution processability and processing temperature requirements, which makes them very attractive as building blocks for flexible electronic systems. Indeed, such systems represent some of the largest families of commercially produced nanomaterials today, and numerous commercial products based on nanoparticle formulations are widely available. This special issue focuses on the rapidly blossoming field of flexible electronics, with a particular focus on the use of nanotechnology to facilitate flexible electronic materials, processes, devices and systems. Contributions to the issue describe the development of nanomaterials—including nanoparticles, nanotubes, nanowires and carbon-based thin films—for use in conductors, transparent electrodes, semiconductors and dielectrics. The articles feature innovations in nanomanufacturing and novel materials, as well as the application of these technologies to advanced flexible devices and systems. As flexible electronics systems move rapidly towards successful commercial deployment, it is extremely likely that they will exploit nanomaterials as building blocks. Developments in the field will help to leverage the power of these materials to realize novel functionalities in flexible form factors. This special issue provides a view of the state of the art in these technologies, and gives a vision of the coming innovations that will make flexible electronics a reality. References [1] Gelinck G H et al 2004 Flexible active-matrix displays and shift registers based on solution-processed organic transistors Nature Mater. 3 106-10 [2] Zhou L, Wanga A, Wu S C, Sun J, Park S and Jackson T N 2006 All-organic active matrix flexible display Appl. Phys. Lett. 88 083502 [3] Fan Z, Ho J C, Jacobson Z A, Razavi H and Javey A 2008 Large-scale, heterogeneous integration of nanowire arrays for image sensor circuitry Proc. Natl Acad. Sci. 105 11066 [4] Sekitani T et al 2009 Organic nonvolatile memory transistors for flexible sensor arrays Science 326 1516-9 [5] Mannsfeld S C B et al 2010 Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers Nature Mater. 9 859-64 [6]Subramanian V, Frechet J M J, Chang P C, Huang D C, Lee J B, Molesa S E, Murphy A R, Redinger D R and Volkman S K 2005 Progress toward development of all-printed RFID tags: materials, processes, and devices Proc. IEEE 93 1330-8 [7] Jung M et al 2010 All-printed and roll-to-roll-printable 13.56 MHz-operated 1 bit RF tag on plastic foils IEEE Trans. Electron. Devices 57 571-80 [8] Kim D-H et al 2011 Epidermal electronics Science 333 838-43 [9] Wagner S and Bauer S 2012 Materials for stretchable electronics MRS Bull. 37 207 [10] Grouchko M, Kamyshny A and Magdassi S 2009 Formation of air-stable copper-silver core-shell nanoparticles for inkjet printing J. Mater. Chem. 19 3057-62 [11] Takei K et al 2010 Nanowire active-matrix circuitry for low-voltage macroscale artificial skin Nature Mater. 9 821-6 [12] Sekitani T, Zschieschang U, Klauk H and Someya T 2010 Flexible organic transistors and circuits with extreme bending stability Nature Mater. 9 1015-22 [13] Park S, Wang G, Cho B, Kim Y, Song S, Ji Y, Yoon M and Lee T 2012 Flexible molecular-scale electronic devices Nature Nanotechnol. 7 438-42

Flexible Vinyl and Urethane Coating and Printing: New Source Performance Standards (NSPS)

EPA Pesticide Factsheets

Learn about the New Source Performance Standards (NSPS) for flexible vinyl and urethane coating and printing by reading the rule summary, the rule history, the code of federal regulations subpart and related rules

Printing Highly Controlled Suspended Carbon Nanotube Network on Micro-patterned Superhydrophobic Flexible Surface

PubMed Central

Li, Bo; Wang, Xin; Jung, Hyun Young; Kim, Young Lae; Robinson, Jeremy T.; Zalalutdinov, Maxim; Hong, Sanghyun; Hao, Ji; Ajayan, Pulickel M.; Wan, Kai-Tak; Jung, Yung Joon

2015-01-01

Suspended single-walled carbon nanotubes (SWCNTs) offer unique functionalities for electronic and electromechanical systems. Due to their outstanding flexible nature, suspended SWCNT architectures have great potential for integration into flexible electronic systems. However, current techniques for integrating SWCNT architectures with flexible substrates are largely absent, especially in a manner that is both scalable and well controlled. Here, we present a new nanostructured transfer paradigm to print scalable and well-defined suspended nano/microscale SWCNT networks on 3D patterned flexible substrates with micro- to nanoscale precision. The underlying printing/transfer mechanism, as well as the mechanical, electromechanical, and mechanical resonance properties of the suspended SWCNTs are characterized, including identifying metrics relevant for reliable and sensitive device structures. Our approach represents a fast, scalable and general method for building suspended nano/micro SWCNT architectures suitable for flexible sensing and actuation systems. PMID:26511284

Printing Highly Controlled Suspended Carbon Nanotube Network on Micro-patterned Superhydrophobic Flexible Surface.

PubMed

Li, Bo; Wang, Xin; Jung, Hyun Young; Kim, Young Lae; Robinson, Jeremy T; Zalalutdinov, Maxim; Hong, Sanghyun; Hao, Ji; Ajayan, Pulickel M; Wan, Kai-Tak; Jung, Yung Joon

2015-10-29

Suspended single-walled carbon nanotubes (SWCNTs) offer unique functionalities for electronic and electromechanical systems. Due to their outstanding flexible nature, suspended SWCNT architectures have great potential for integration into flexible electronic systems. However, current techniques for integrating SWCNT architectures with flexible substrates are largely absent, especially in a manner that is both scalable and well controlled. Here, we present a new nanostructured transfer paradigm to print scalable and well-defined suspended nano/microscale SWCNT networks on 3D patterned flexible substrates with micro- to nanoscale precision. The underlying printing/transfer mechanism, as well as the mechanical, electromechanical, and mechanical resonance properties of the suspended SWCNTs are characterized, including identifying metrics relevant for reliable and sensitive device structures. Our approach represents a fast, scalable and general method for building suspended nano/micro SWCNT architectures suitable for flexible sensing and actuation systems.

High-Throughput Printing Process for Flexible Electronics

NASA Astrophysics Data System (ADS)

Hyun, Woo Jin

Printed electronics is an emerging field for manufacturing electronic devices with low cost and minimal material waste for a variety of applications including displays, distributed sensing, smart packaging, and energy management. Moreover, its compatibility with roll-to-roll production formats and flexible substrates is desirable for continuous, high-throughput production of flexible electronics. Despite the promise, however, the roll-to-roll production of printed electronics is quite challenging due to web movement hindering accurate ink registration and high-fidelity printing. In this talk, I will present a promising strategy for roll-to-roll production using a novel printing process that we term SCALE (Self-aligned Capillarity-Assisted Lithography for Electronics). By utilizing capillarity of liquid inks on nano/micro-structured substrates, the SCALE process facilitates high-resolution and self-aligned patterning of electrically functional inks with greatly improved printing tolerance. I will show the fabrication of key building blocks (e.g. transistor, resistor, capacitor) for electronic circuits using the SCALE process on plastics.

Malware Memory Analysis for Non specialists: Investigating Publicly Available Memory Images for Prolaco and SpyEye

DTIC Science & Technology

2013-10-01

1_doc_RCData_612|virus|Trojan|rootkit|worm|Prolaco|rundll|msiexec|google|wmimngr|jusche d|wfmngr|wupmgr| java |wpmgr|nvscpapisvr)’ ” results in the...hashdump Dumps passwords hashes (LM/NTLM) from memory hibinfo Dump hibernation file information hivedump Prints out a hive hivelist Print list of

Flexible composite film for printed circuit board

NASA Technical Reports Server (NTRS)

Yabe, K.; Asakura, M.; Tanaka, H.; Soda, A.

1982-01-01

A flexible printed circuit for a printed circuit board in which layers of reaction product composed of a combination of phenoxy resin - polyisocyanate - brominated epoxy resin, and in which the equivalent ratio of those functional groups is hydroxyl group: isocyanate group: epoxy group - 1 : 0.2 to 2 : 0.5 to 3 are laminated on at least one side of saturated polyester film is discussed.

A Bioactive Carbon Nanotube-Based Ink for Printing 2D and 3D Flexible Electronics.

PubMed

Shin, Su Ryon; Farzad, Raziyeh; Tamayol, Ali; Manoharan, Vijayan; Mostafalu, Pooria; Zhang, Yu Shrike; Akbari, Mohsen; Jung, Sung Mi; Kim, Duckjin; Comotto, Mattia; Annabi, Nasim; Al-Hazmi, Faten Ebrahim; Dokmeci, Mehmet R; Khademhosseini, Ali

2016-05-01

The development of electrically conductive carbon nanotube-based inks is reported. Using these inks, 2D and 3D structures are printed on various flexible substrates such as paper, hydrogels, and elastomers. The printed patterns have mechanical and electrical properties that make them beneficial for various biological applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Age differences and format effects in working memory.

PubMed

Foos, Paul W; Goolkasian, Paula

2010-07-01

Format effects refer to lower recall of printed words from working memory when compared to spoken words or pictures. These effects have been attributed to an attenuation of attention to printed words. The present experiment compares younger and older adults' recall of three or six items presented as pictures, spoken words, printed words, and alternating case WoRdS. The latter stimuli have been shown to increase attention to printed words and, thus, reduce format effects. The question of interest was whether these stimuli would also reduce format effects for older adults whose working memory capacity has fewer attentional resources to allocate. Results showed that older adults performed as well as younger adults with three items but less well with six and that format effects were reduced for both age groups, but more for young, when alternating case words were used. Other findings regarding executive control of working memory are discussed. The obtained differences support models of reduced capacity in older adult working memory.

Assembling surface mounted components on ink-jet printed double sided paper circuit board.

PubMed

Andersson, Henrik A; Manuilskiy, Anatoliy; Haller, Stefan; Hummelgård, Magnus; Sidén, Johan; Hummelgård, Christine; Olin, Håkan; Nilsson, Hans-Erik

2014-03-07

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed.

Low-voltage-operated organic one-time programmable memory using printed organic thin-film transistors and antifuse capacitors.

PubMed

Jung, Soon-Won; Na, Bock Soon; Park, Chan Woo; Koo, Jae Bon

2014-11-01

We demonstrate an organic one-time programmable memory cell formed entirely at plastic-compatible temperatures. All the processes are performed at below 130 degrees C. Our memory cell consists of a printed organic transistor and an organic capacitor. Inkjet-printed organic transistors are fabricated by using high-k polymer dielectric blends comprising poly(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] and poly(methyl methacrylate) (PMMA) for low-voltage operation. P(NDI2OD-T2) transistors have a high field-effect mobility of 0.2 cm2/Vs and a low operation gate voltage of less than 10 V. The operation voltage effectively decreases owing to the high permittivity of the P(VDF-TrFE):PMMA blended film. The data in the memory cell are programmed by electrically breaking the organic capacitor. The organic capacitor acts like an antifuse capacitor, because it is initially open, and it becomes permanently short-circuited by applying a high voltage. The organic memory cells are programmed with 4 V, and they are read out with 2 V. The memory data are read out by sensing the current in the memory cell. The printed organic one-time programmable memory is suitable for applications storing small amount of data, such as low-cost radio-frequency identification (RFID) tag.

Resistive Switching in All-Printed, Flexible and Hybrid MoS2-PVA Nanocomposite based Memristive Device Fabricated by Reverse Offset

PubMed Central

Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Gul, Jahan Zeb; Kim, Soo-Wan; Lim, Jong Hwan; Choi, Kyung Hyun

2016-01-01

Owing to the increasing interest in the nonvolatile memory devices, resistive switching based on hybrid nanocomposite of a 2D material, molybdenum disulphide (MoS2) and polyvinyl alcohol (PVA) is explored in this work. As a proof of concept, we have demonstrated the fabrication of a memory device with the configuration of PET/Ag/MoS2-PVA/Ag via an all printed, hybrid, and state of the art fabrication approach. Bottom Ag electrodes, active layer of hybrid MoS2-PVA nanocomposite and top Ag electrode are deposited by reverse offset, electrohydrodynamic (EHD) atomization and electrohydrodynamic (EHD) patterning respectively. The fabricated device displayed characteristic bistable, nonvolatile and rewritable resistive switching behavior at a low operating voltage. A decent off/on ratio, high retention time, and large endurance of 1.28 × 102, 105 sec and 1000 voltage sweeps were recorded respectively. Double logarithmic curve satisfy the trap controlled space charge limited current (TCSCLC) model in high resistance state (HRS) and ohmic model in low resistance state (LRS). Bendability test at various bending diameters (50-2 mm) for 1500 cycles was carried out to show the mechanical robustness of fabricated device. PMID:27811977

Interference Effects on the Recall of Pictures, Printed Words, and Spoken Words.

ERIC Educational Resources Information Center

Burton, John K.; Bruning, Roger H.

1982-01-01

Nouns were presented in triads as pictures, printed words, or spoken words and followed by various types of interference. Measures of short- and long-term memory were obtained. In short-term memory, pictorial superiority occurred with acoustic, and visual and acoustic, but not visual interference. Long-term memory showed superior recall for…

A thin-film microprocessor with inkjet print-programmable memory

NASA Astrophysics Data System (ADS)

Myny, Kris; Smout, Steve; Rockelé, Maarten; Bhoolokam, Ajay; Ke, Tung Huei; Steudel, Soeren; Cobb, Brian; Gulati, Aashini; Rodriguez, Francisco Gonzalez; Obata, Koji; Marinkovic, Marko; Pham, Duy-Vu; Hoppe, Arne; Gelinck, Gerwin H.; Genoe, Jan; Dehaene, Wim; Heremans, Paul

2014-12-01

The Internet of Things is driving extensive efforts to develop intelligent everyday objects. This requires seamless integration of relatively simple electronics, for example through `stick-on' electronics labels. We believe the future evolution of this technology will be governed by Wright's Law, which was first proposed in 1936 and states that the cost of a product decreases with cumulative production. This implies that a generic electronic device that can be tailored for application-specific requirements during downstream integration would be a cornerstone in the development of the Internet of Things. We present an 8-bit thin-film microprocessor with a write-once, read-many (WORM) instruction generator that can be programmed after manufacture via inkjet printing. The processor combines organic p-type and soluble oxide n-type thin-film transistors in a new flavor of the familiar complementary transistor technology with the potential to be manufactured on a very thin polyimide film, enabling low-cost flexible electronics. It operates at 6.5 V and reaches clock frequencies up to 2.1 kHz. An instruction set of 16 code lines, each line providing a 9 bit instruction, is defined by means of inkjet printing of conductive silver inks.

Multi-shape active composites by 3D printing of digital shape memory polymers

NASA Astrophysics Data System (ADS)

Wu, Jiangtao; Yuan, Chao; Ding, Zhen; Isakov, Michael; Mao, Yiqi; Wang, Tiejun; Dunn, Martin L.; Qi, H. Jerry

2016-04-01

Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers - digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure. After a simple single-step thermomechanical programming process, the fiber families can be sequentially activated to bend when the temperature is increased. By tuning the volume fraction of the fibers, bending deformation can be controlled. We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design. We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat. With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

Multi-shape active composites by 3D printing of digital shape memory polymers.

PubMed

Wu, Jiangtao; Yuan, Chao; Ding, Zhen; Isakov, Michael; Mao, Yiqi; Wang, Tiejun; Dunn, Martin L; Qi, H Jerry

2016-04-13

Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers - digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure. After a simple single-step thermomechanical programming process, the fiber families can be sequentially activated to bend when the temperature is increased. By tuning the volume fraction of the fibers, bending deformation can be controlled. We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design. We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat. With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

Multi-shape active composites by 3D printing of digital shape memory polymers

PubMed Central

Wu, Jiangtao; Yuan, Chao; Ding, Zhen; Isakov, Michael; Mao, Yiqi; Wang, Tiejun; Dunn, Martin L.; Qi, H. Jerry

2016-01-01

Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers – digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure. After a simple single-step thermomechanical programming process, the fiber families can be sequentially activated to bend when the temperature is increased. By tuning the volume fraction of the fibers, bending deformation can be controlled. We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design. We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat. With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications. PMID:27071543

Characterization of polymer silver pastes for screen printed flexible RFID antennas

NASA Astrophysics Data System (ADS)

Janeczek, Kamil; Jakubowska, Małgorzata; Futera, Konrad; MłoŻniak, Anna; Kozioł, GraŻyna; Araźna, Aneta

Radio Frequency Identification (RFID) systems have become more and more popular in the last few years because of their wide application fields, such as supply chain management and logistics. To continue their development further investigations of new conductive materials for fabrication of RFID transponders' antennas are necessary to be carried out. These materials should provide high flexibility and good radiation performance of printed antennas. In this paper, two polymer silver pastes based on silver flakes were characterized with regard to manufacturing of flexible RFID antennas with screen printing technique. Foil and paper were used as a substrate materials. Surface profile of the printed antennas was measured using an optical profilometer and their resistance was measured with a four-point-probe method. Antenna flexibility was evaluated in cyclic bending tests and its performance with reflection coefficient measurements with the use of differential probe connected to a vector network analyzer. In addition, a maximum read distance of a fabricated RFID transponder was measured.

Flexible Piezoresistive Sensors Embedded in 3D Printed Tires

PubMed Central

Emon, Md Omar Faruk; Choi, Jae-Won

2017-01-01

In this article, we report the development of a flexible, 3D printable piezoresistive pressure sensor capable of measuring force and detecting the location of the force. The multilayer sensor comprises of an ionic liquid-based piezoresistive intermediate layer in between carbon nanotube (CNT)-based stretchable electrodes. A sensor containing an array of different sensing units was embedded on the inner liner surface of a 3D printed tire to provide with force information at different points of contact between the tire and road. Four scaled tires, as well as wheels, were 3D printed using a flexible and a rigid material, respectively, which were later assembled with a 3D-printed chassis. Only one tire was equipped with a sensor and the chassis was driven through a motorized linear stage at different speeds and load conditions to evaluate the sensor performance. The sensor was fabricated via molding and screen printing processes using a commercially available 3D-printable photopolymer as 3D printing is our target manufacturing technique to fabricate the entire tire assembly with the sensor. Results show that the proposed sensors, inserted in the 3D printed tire assembly, could detect forces, as well as their locations, properly. PMID:28327533

Flexible Piezoresistive Sensors Embedded in 3D Printed Tires.

PubMed

Emon, Md Omar Faruk; Choi, Jae-Won

2017-03-22

In this article, we report the development of a flexible, 3D printable piezoresistive pressure sensor capable of measuring force and detecting the location of the force. The multilayer sensor comprises of an ionic liquid-based piezoresistive intermediate layer in between carbon nanotube (CNT)-based stretchable electrodes. A sensor containing an array of different sensing units was embedded on the inner liner surface of a 3D printed tire to provide with force information at different points of contact between the tire and road. Four scaled tires, as well as wheels, were 3D printed using a flexible and a rigid material, respectively, which were later assembled with a 3D-printed chassis. Only one tire was equipped with a sensor and the chassis was driven through a motorized linear stage at different speeds and load conditions to evaluate the sensor performance. The sensor was fabricated via molding and screen printing processes using a commercially available 3D-printable photopolymer as 3D printing is our target manufacturing technique to fabricate the entire tire assembly with the sensor. Results show that the proposed sensors, inserted in the 3D printed tire assembly, could detect forces, as well as their locations, properly.

Inkjet-Printed Electrodes on A4 Paper Substrates for Low-Cost, Disposable, and Flexible Asymmetric Supercapacitors.

PubMed

Sundriyal, Poonam; Bhattacharya, Shantanu

2017-11-08

Printed electronics is widely gaining much attention for compact and high-performance energy-storage devices because of the advancement of flexible electronics. The development of a low-cost current collector, selection, and utilization of the proper material deposition tool and improvement of the device energy density are major challenges for the existing flexible supercapacitors. In this paper, we have reported an inkjet-printed solid-state asymmetric supercapacitor on commercial A4 paper using a low-cost desktop printer (EPSON L130). The physical properties of all inks have been carefully optimized so that the developed inks are within the printable range, i.e., Fromm number of 4 < Z < 14 for all inks. The paper substrate is made conducting (sheet resistance ∼ 1.6 Ω/sq) by printing 40 layers of conducting graphene oxide (GO) ink on its surface. The developed conducting patterns on paper are further printed with a GO-MnO 2 nanocomposite ink to make a positive electrode, and another such structure is printed with activated carbon ink to form a negative electrode. A combination of both of these electrodes is outlaid by fabricating an asymmetric supercapacitor. The assembled asymmetric supercapacitor with poly(vinyl alcohol) (PVA)-LiCl gel electrolyte shows a stable potential window of 0-2.0 V and exhibits outstanding flexibility, good cyclic stability, high rate capability, and high energy density. The fabricated paper-substrate-based flexible asymmetric supercapacitor also displays an excellent electrochemical performances, e.g., a maximum areal capacitance of 1.586 F/cm 2 (1023 F/g) at a current density of 4 mA/cm 2 , highest energy density of 22 mWh/cm 3 at a power density of 0.099 W/cm 3 , a capacity retention of 89.6% even after 9000 charge-discharge cycles, and a low charge-transfer resistance of 2.3 Ω. So, utilization of inkjet printing for the development of paper-based flexible electronics has a strong potential for embedding into the next generation low-cost, compact, and wearable energy-storage devices and other printed electronic applications.

Flexible Strain Sensors Fabricated by Meniscus-Guided Printing of Carbon Nanotube-Polymer Composites.

PubMed

Wajahat, Muhammad; Lee, Sanghyeon; Kim, Jung Hyun; Chang, Won Suk; Pyo, Jaeyeon; Cho, Sung Ho; Seol, Seung Kwon

2018-06-13

Printed strain sensors have promising potential as a human-machine interface (HMI) for health-monitoring systems, human-friendly wearable interactive systems, and smart robotics. Herein, flexible strain sensors based on carbon nanotube (CNT)-polymer composites were fabricated by meniscus-guided printing using a CNT ink formulated from multiwall nanotubes (MWNTs) and polyvinylpyrrolidone (PVP); the ink was suitable for micropatterning on nonflat (or curved) substrates and even three-dimensional structures. The printed strain sensors exhibit a reproducible response to applied tensile and compressive strains, having gauge factors of 13.07 under tensile strain and 12.87 under compressive strain; they also exhibit high stability during ∼1500 bending cycles. Applied strains induce a contact rearrangement of the MWNTs and a change in the tunneling distance between them, resulting in a change in the resistance (Δ R/ R 0 ) of the sensor. Printed MWNT-PVP sensors were used in gloves for finger movement detection; these can be applied to human motion detection and remote control of robotic equipment. Our results demonstrate that meniscus-guided printing using CNT inks can produce highly flexible, sensitive, and inexpensive HMI devices.

Fully Printed Organic-Inorganic Nanocomposites for Flexible Thermoelectric Applications.

PubMed

Ou, Canlin; Sangle, Abhijeet L; Datta, Anuja; Jing, Qingshen; Busolo, Tommaso; Chalklen, Thomas; Narayan, Vijay; Kar-Narayan, Sohini

2018-06-13

Thermoelectric materials, capable of interconverting heat and electricity, are attractive for applications in thermal energy harvesting as a means to power wireless sensors, wearable devices, and portable electronics. However, traditional inorganic thermoelectric materials pose significant challenges due to high cost, toxicity, scarcity, and brittleness, particularly when it comes to applications requiring flexibility. Here, we investigate organic-inorganic nanocomposites that have been developed from bespoke inks which are printed via an aerosol jet printing method onto flexible substrates. For this purpose, a novel in situ aerosol mixing method has been developed to ensure uniform distribution of Bi 2 Te 3 /Sb 2 Te 3 nanocrystals, fabricated by a scalable solvothermal synthesis method, within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate matrix. The thermoelectric properties of the resulting printed nanocomposite structures have been evaluated as a function of composition, and the power factor was found to be maximum (∼30 μW/mK 2 ) for a nominal loading fraction of 85 wt % Sb 2 Te 3 nanoflakes. Importantly, the printed nanocomposites were found to be stable and robust upon repeated flexing to curvatures up to 300 m -1 , making these hybrid materials particularly suitable for flexible thermoelectric applications.

Printed electronic on flexible and glass substrates

NASA Astrophysics Data System (ADS)

Futera, Konrad; Jakubowska, Małgorzata; Kozioł, Grażyna

2010-09-01

Organic electronics is a platform technology that enables multiple applications based on organic electronics but varied in specifications. Organic electronics is based on the combination of new materials and cost-effective, large area production processes that provide new fields of application. Organic electronic by its size, weight, flexibility and environmental friendliness electronics enables low cost production of numerous electrical components and provides for such promising fields of application as: intelligent packaging, low cost RFID, flexible solar cells, disposable diagnostic devices or games, and printed batteries [1]. The paper presents results of inkjetted electronics elements on flexible and glass substrates. The investigations was target on characterizing shape, surface and geometry of printed structures. Variety of substrates were investigated, within some, low cost, non specialized substrate, design for other purposes than organic electronic.

Screen printed, transparent, and flexible electrodes based on graphene nanoplatelet pastes

NASA Astrophysics Data System (ADS)

Wróblewski, Grzegorz; Janczak, Daniel

Transparent, flexible and conducting graphene films were produced by screen printing method using printing pastes based on graphene nanoplatelets in polymer matrix. The transparency of received layers and the mechanical resistivity in several bending cycles were measured. Subsequently percolation threshold was investigated. Graphene layers were printed on diverse substrates (glass, Al2O3, PET) and afterwards for samples printed on glass different firing atmospheres (N2, H2, air) were studied. Best firing results (resistance decrease) were obtained for treatment in 250 °C in atmosphere of air. Finally investigation results were used to produce a transparent and elastic electrode for an electroluminescent display, showing the application potential of our graphene nanocomposite pastes.

75 FR 59179 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-27

... (RACT) for sources covered by EPA's Control Techniques Guidelines (CTG) for flexible packaging printing... Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control Techniques Guidelines for Flexible Packaging Printing AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY...

On the optimization of low-cost FDM 3D printers for accurate replication of patient-specific abdominal aortic aneurysm geometry.

PubMed

Chung, Michael; Radacsi, Norbert; Robert, Colin; McCarthy, Edward D; Callanan, Anthony; Conlisk, Noel; Hoskins, Peter R; Koutsos, Vasileios

2018-01-01

There is a potential for direct model manufacturing of abdominal aortic aneurysm (AAA) using 3D printing technique for generating flexible semi-transparent prototypes. A patient-specific AAA model was manufactured using fused deposition modelling (FDM) 3D printing technology. A flexible, semi-transparent thermoplastic polyurethane (TPU), called Cheetah Water (produced by Ninjatek, USA), was used as the flexible, transparent material for model manufacture with a hydrophilic support structure 3D printed with polyvinyl alcohol (PVA). Printing parameters were investigated to evaluate their effect on 3D-printing precision and transparency of the final model. ISO standard tear resistance tests were carried out on Ninjatek Cheetah specimens for a comparison of tear strength with silicone rubbers. It was found that an increase in printing speed decreased printing accuracy, whilst using an infill percentage of 100% and printing nozzle temperature of 255 °C produced the most transparent results. The model had fair transparency, allowing external inspection of model inserts such as stent grafts, and good flexibility with an overall discrepancy between CAD and physical model average wall thicknesses of 0.05 mm (2.5% thicker than the CAD model). The tear resistance test found Ninjatek Cheetah TPU to have an average tear resistance of 83 kN/m, higher than any of the silicone rubbers used in previous AAA model manufacture. The model had lower cost (4.50 GBP per model), shorter manufacturing time (25 h 3 min) and an acceptable level of accuracy (2.61% error) compared to other methods. It was concluded that the model would be of use in endovascular aneurysm repair planning and education, particularly for practicing placement of hooked or barbed stents, due to the model's balance of flexibility, transparency, robustness and cost-effectiveness.

Tensile and fatigue behaviors of printed Ag thin films on flexible substrates

NASA Astrophysics Data System (ADS)

Sim, Gi-Dong; Won, Sejeong; Lee, Soon-Bok

2012-11-01

Flexible electronics using nanoparticle (NP) printing has been highlighted as a key technology enabling eco-friendly, low-cost, and large-area fabrication. For NP-based printing to be used as a successive alternative to photolithography and vacuum deposition, stretchability and long term reliability must be considered. This paper reports the stretchability and fatigue behavior of 100 nm thick NP-based silver thin films printed on polyethylene-terephthalate substrate and compares it to films deposited by electron-beam evaporation. NP-based films show stretchability and fatigue life comparable to evaporated films with intergranular fracture as the dominant failure mechanism.

Challenges and the state of the technology for printed sensor arrays for structural monitoring

NASA Astrophysics Data System (ADS)

Joshi, Shiv; Bland, Scott; DeMott, Robert; Anderson, Nickolas; Jursich, Gregory

2017-04-01

Printed sensor arrays are attractive for reliable, low-cost, and large-area mapping of structural systems. These sensor arrays can be printed on flexible substrates or directly on monitored structural parts. This technology is sought for continuous or on-demand real-time diagnosis and prognosis of complex structural components. In the past decade, many innovative technologies and functional materials have been explored to develop printed electronics and sensors. For example, an all-printed strain sensor array is a recent example of a low-cost, flexible and light-weight system that provides a reliable method for monitoring the state of aircraft structural parts. Among all-printing techniques, screen and inkjet printing methods are well suited for smaller-scale prototyping and have drawn much interest due to maturity of printing procedures and availability of compatible inks and substrates. Screen printing relies on a mask (screen) to transfer a pattern onto a substrate. Screen printing is widely used because of the high printing speed, large selection of ink/substrate materials, and capability of making complex multilayer devices. The complexity of collecting signals from a large number of sensors over a large area necessitates signal multiplexing electronics that need to be printed on flexible substrate or structure. As a result, these components are subjected to same deformation, temperature and other parameters for which sensor arrays are designed. The characteristics of these electronic components, such as transistors, are affected by deformation and other environmental parameters which can lead to erroneous sensed parameters. The manufacturing and functional challenges of the technology of printed sensor array systems for structural state monitoring are the focus of this presentation. Specific examples of strain sensor arrays will be presented to highlight the technical challenges.

Fabrication of tough epoxy with shape memory effects by UV-assisted direct-ink write printing.

PubMed

Chen, Kaijuan; Kuang, Xiao; Li, Vincent; Kang, Guozheng; Qi, H Jerry

2018-03-07

3D printing of epoxy-based shape memory polymers with high mechanical strength, excellent thermal stability and chemical resistance is highly desirable for practical applications. However, thermally cured epoxy in general is difficult to print directly. There have been limited numbers of successes in printing epoxy but they suffer from relatively poor mechanical properties. Here, we present an ultraviolet (UV)-assisted 3D printing of thermally cured epoxy composites with high tensile toughness via a two-stage curing approach. The ink containing UV curable resin and epoxy oligomer is used for UV-assisted direct-ink write (DIW)-based 3D printing followed by thermal curing of the part containing the epoxy oligomer. The UV curable resin forms a network by photo polymerization after the 1st stage of UV curing, which can maintain the printed architecture at an elevated temperature. The 2nd stage thermal curing of the epoxy oligomer yields an interpenetrating polymer network (IPN) composite with highly enhanced mechanical properties. It is found that the printed IPN epoxy composites enabled by the two-stage curing show isotropic mechanical properties and high tensile toughness. We demonstrated that the 3D-printed high-toughness epoxy composites show good shape memory properties. This UV-assisted DIW 3D printing via a two-stage curing method can broaden the application of 3D printing to fabricate thermoset materials with enhanced tensile toughness and tunable properties for high-performance and functional applications.

Transparent Large-Area MoS2 Phototransistors with Inkjet-Printed Components on Flexible Platforms.

PubMed

Kim, Tae-Young; Ha, Jewook; Cho, Kyungjune; Pak, Jinsu; Seo, Jiseok; Park, Jongjang; Kim, Jae-Keun; Chung, Seungjun; Hong, Yongtaek; Lee, Takhee

2017-10-24

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have gained considerable attention as an emerging semiconductor due to their promising atomically thin film characteristics with good field-effect mobility and a tunable band gap energy. However, their electronic applications have been generally realized with conventional inorganic electrodes and dielectrics implemented using conventional photolithography or transferring processes that are not compatible with large-area and flexible device applications. To facilitate the advantages of 2D TMDCs in practical applications, strategies for realizing flexible and transparent 2D electronics using low-temperature, large-area, and low-cost processes should be developed. Motivated by this challenge, we report fully printed transparent chemical vapor deposition (CVD)-synthesized monolayer molybdenum disulfide (MoS 2 ) phototransistor arrays on flexible polymer substrates. All the electronic components, including dielectric and electrodes, were directly deposited with mechanically tolerable organic materials by inkjet-printing technology onto transferred monolayer MoS 2 , and their annealing temperature of <180 °C allows the direct fabrication on commercial flexible substrates without additional assisted-structures. By integrating the soft organic components with ultrathin MoS 2 , the fully printed MoS 2 phototransistors exhibit excellent transparency and mechanically stable operation.

77 FR 7930 - Improving Government Regulations; Unified Agenda of Federal Regulatory and Deregulatory Actions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-13

... the Regulatory Flexibility Act (5 U.S.C. 602), the Department of Defense's printed agenda entries... section 610 of the Regulatory Flexibility Act. Printing of these entries is limited to fields that contain...D Intelligence Interrogations, Detainee Debriefings, and Tactical Questioning. This rule only...

Ultraflexible and robust graphene supercapacitors printed on textiles for wearable electronics applications

NASA Astrophysics Data System (ADS)

Abdelkader, Amr M.; Karim, Nazmul; Vallés, Cristina; Afroj, Shaila; Novoselov, Kostya S.; Yeates, Stephen G.

2017-09-01

Printed graphene supercapacitors have the potential to empower tomorrow’s wearable electronics. We report a solid-state flexible supercapacitor device printed on textiles using graphene oxide ink and a screen-printing technique. After printing, graphene oxide was reduced in situ via a rapid electrochemical method avoiding the use of any reducing reagents that may damage the textile substrates. The printed electrodes exhibited excellent mechanical stability due to the strong interaction between the ink and textile substrate. The unique hierarchical porous structure of the electrodes facilitated ionic diffusion and maximised the surface area available for the electrolyte/active material interface. The obtained device showed outstanding cyclic stability over 10 000 cycles and maintained excellent mechanical flexibility, which is necessary for wearable applications. The simple printing technique is readily scalable and avoids the problems associated with fabricating supercapacitor devices made of conductive yarn, as previously reported in the literature.

Organic electronics with polymer dielectrics on plastic substrates fabricated via transfer printing

NASA Astrophysics Data System (ADS)

Hines, Daniel R.

Printing methods are fast becoming important processing techniques for the fabrication of flexible electronics. Some goals for flexible electronics are to produce cheap, lightweight, disposable radio frequency identification (RFID) tags, very large flexible displays that can be produced in a roll-to-roll process and wearable electronics for both the clothing and medical industries. Such applications will require fabrication processes for the assembly of dissimilar materials onto a common substrate in ways that are compatible with organic and polymeric materials as well as traditional solid-state electronic materials. A transfer printing method has been developed with these goals and application in mind. This printing method relies primarily on differential adhesion where no chemical processing is performed on the device substrate. It is compatible with a wide variety of materials with each component printed in exactly the same way, thus avoiding any mixed processing steps on the device substrate. The adhesion requirements of one material printed onto a second are studied by measuring the surface energy of both materials and by surface treatments such as plasma exposure or the application of self-assembled monolayers (SAM). Transfer printing has been developed within the context of fabricating organic electronics onto plastic substrates because these materials introduce unique opportunities associated with processing conditions not typically required for traditional semiconducting materials. Compared to silicon, organic semiconductors are soft materials that require low temperature processing and are extremely sensitive to chemical processing and environmental contamination. The transfer printing process has been developed for the important and commonly used organic semiconducting materials, pentacene (Pn) and poly(3-hexylthiophene) (P3HT). A three-step printing process has been developed by which these materials are printed onto an electrode subassembly consisting of previously printed electrodes separated by a polymer dielectric layer all on a plastic substrate. These bottom contact, flexible organic thin-film transistors (OTFT) have been compared to unprinted (reference) devices consisting of top contact electrodes and a silicon dioxide dielectric layer on a silicon substrate. Printed Pn and P3HT TFTs have been shown to out-perform the reference devices. This enhancement has been attributed to an annealing under pressure of the organic semiconducting material.

4D Printing of Shape Memory-Based Personalized Endoluminal Medical Devices.

PubMed

Zarek, Matt; Mansour, Nicola; Shapira, Shir; Cohn, Daniel

2017-01-01

The convergence of additive manufacturing and shape-morphing materials is promising for the advancement of personalized medical devices. The capability to transform 3D objects from one shape to another, right off the print bed, is known as 4D printing. Shape memory thermosets can be tailored to have a range of thermomechanical properties favorable to medical devices, but processing them is a challenge because they are insoluble and do not flow at any temperature. This study presents here a strategy to capitalize on a series of medical imaging modalities to construct a printable shape memory endoluminal device, exemplified by a tracheal stent. A methacrylated polycaprolactone precursor with a molecular weight of 10 000 g mol -1 is printed with a UV-LED stereolithography printer based on anatomical data. This approach converges with the zeitgeist of personalized medicine and it is anticipated that it will broadly expand the application of shape memory-exhibiting biomedical devices to myriad clinical indications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Iconographic dental typography. A dental character font for computer graphics.

PubMed

McCormack, J

1991-06-08

The recent massive increase in available memory for microcomputers now allows multiple font faces to be stored in computer RAM memory for instant access to the screen and for printed output. Fonts can be constructed in which the characters are not just letters or numbers, but are miniature graphic icons--in this instance pictures of teeth. When printed on an appropriate laser printer, this produces printed graphics of publishing quality.

Ink-jet printing of graphene for flexible electronics: An environmentally-friendly approach

NASA Astrophysics Data System (ADS)

Capasso, A.; Del Rio Castillo, A. E.; Sun, H.; Ansaldo, A.; Pellegrini, V.; Bonaccorso, F.

2015-12-01

Mechanical flexibility is considered an asset in consumer electronics and next-generation electronic systems. Printed and flexible electronic devices could be embedded into clothing or other surfaces at home or office or in many products such as low-cost sensors integrated in transparent and flexible surfaces. In this context inks based on graphene and related two-dimensional materials (2DMs) are gaining increasing attention owing to their exceptional (opto)electronic, electrochemical and mechanical properties. The current limitation relies on the use of solvents, providing stable dispersions of graphene and 2DMs and fitting the proper fluidic requirements for printing, which are in general not environmentally benign, and with high boiling point. Non-toxic and low boiling point solvents do not possess the required rheological properties (i.e., surface tension, viscosity and density) for the solution processing of graphene and 2DMs. Such solvents (e.g., water, alcohols) require the addition of stabilizing agents such as polymers or surfactants for the dispersion of graphene and 2DMs, which however unavoidably corrupt their properties, thus preventing their use for the target application. Here, we demonstrate a viable strategy to tune the fluidic properties of water/ethanol mixtures (low-boiling point solvents) to first effectively exfoliate graphite and then disperse graphene flakes to formulate graphene-based inks. We demonstrate that such inks can be used to print conductive stripes (sheet resistance of ~13 kΩ/□) on flexible substrates (polyethylene terephthalate), moving a step forward towards the realization of graphene-based printed electronic devices.

Active materials by four-dimension printing

NASA Astrophysics Data System (ADS)

Ge, Qi; Qi, H. Jerry; Dunn, Martin L.

2013-09-01

We advance a paradigm of printed active composite materials realized by directly printing glassy shape memory polymer fibers in an elastomeric matrix. We imbue the active composites with intelligence via a programmed lamina and laminate architecture and a subsequent thermomechanical training process. The initial configuration is created by three-dimension (3D) printing, and then the programmed action of the shape memory fibers creates time dependence of the configuration—the four-dimension (4D) aspect. We design and print laminates in thin plate form that can be thermomechanically programmed to assume complex three-dimensional configurations including bent, coiled, and twisted strips, folded shapes, and complex contoured shapes with nonuniform, spatially varying curvature. The original flat plate shape can be recovered by heating the material again. We also show how the printed active composites can be directly integrated with other printed functionalities to create devices; here we demonstrate this by creating a structure that can assemble itself.

Laser-Assisted Reduction of Highly Conductive Circuits Based on Copper Nitrate for Flexible Printed Sensors

NASA Astrophysics Data System (ADS)

Bai, Shi; Zhang, Shigang; Zhou, Weiping; Ma, Delong; Ma, Ying; Joshi, Pooran; Hu, Anming

2017-10-01

Stretchable electronic sensing devices are defining the path toward wearable electronics. High-performance flexible strain sensors attached on clothing or human skin are required for potential applications in the entertainment, health monitoring, and medical care sectors. In this work, conducting copper electrodes were fabricated on polydimethylsiloxane as sensitive stretchable microsensors by integrating laser direct writing and transfer printing approaches. The copper electrode was reduced from copper salt using laser writing rather than the general approach of printing with pre-synthesized copper or copper oxide nanoparticles. An electrical resistivity of 96 μΩ cm was achieved on 40-μm-thick Cu electrodes on flexible substrates. The motion sensing functionality successfully demonstrated a high sensitivity and mechanical robustness. This in situ fabrication method leads to a path toward electronic devices on flexible substrates.[Figure not available: see fulltext.

Flexible substrate for printed wiring

NASA Technical Reports Server (NTRS)

Asakura, M.; Yabe, K.; Tanaka, H.; Soda, A.

1982-01-01

A very flexible substrate for printed wiring is disclosed which is composed of a blend of phenoxy resin-polyisocyanate-brominated epoxy resin in which the equivalent ration of the functional groups is hydroxyl grouped: isocyanate group: epoxy group = 1:0.2 to 2:0.5 to 3. The product has outstanding solder resistance and is applied to metal without using adhesives.

A silicon-on-insulator complementary-metal-oxide-semiconductor compatible flexible electronics technology

NASA Astrophysics Data System (ADS)

Tu, Hongen; Xu, Yong

2012-07-01

This paper reports a simple flexible electronics technology that is compatible with silicon-on-insulator (SOI) complementary-metal-oxide-semiconductor (CMOS) processes. Compared with existing technologies such as direct fabrication on flexible substrates and transfer printing, the main advantage of this technology is its post-SOI-CMOS compatibility. Consequently, high-performance and high-density CMOS circuits can be first fabricated on SOI wafers using commercial foundry and then be integrated into flexible substrates. The yield is also improved by eliminating the transfer printing step. Furthermore, this technology allows the integration of various sensors and microfluidic devices. To prove the concept of this technology, flexible MOSFETs have been demonstrated.

3-D printing of liquid metals for stretchable and flexible conductors

NASA Astrophysics Data System (ADS)

Trlica, Chris; Parekh, Dishit Paresh; Panich, Lazar; Ladd, Collin; Dickey, Michael D.

2014-06-01

3-D printing is an emerging technology that has been used primarily on small scales for rapid prototyping, but which could also herald a wider movement towards decentralized, highly customizable manufacturing. Polymers are the most common materials to be 3-D printed today, but there is great demand for a way to easily print metals. Existing techniques for 3-D printing metals tend to be expensive and energy-intensive, and usually require high temperatures or pressures, making them incompatible with polymers, organics, soft materials, and biological materials. Here, we describe room temperature liquid metals as complements to polymers for 3-D printing applications. These metals enable the fabrication of soft, flexible, and stretchable devices. We survey potential room temperature liquid metal candidates and describe the benefits of gallium and its alloys for these purposes. We demonstrate the direct printing of a liquid gallium alloy in both 2-D and 3-D and highlight the structures and shapes that can be fabricated using these processes.

Department of Defense Semiannual Regulatory Agenda

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-20

... Register is mandated for the regulatory flexibility agendas required by the Regulatory Flexibility Act (5 U... the Agency's regulatory flexibility agenda, in accordance with the Regulatory Flexibility Act, because... Flexibility Act. Printing of these entries is limited to fields that contain information required by the...

Adhesive Stretchable Printed Conductive Thin Film Patterns on PDMS Surface with an Atmospheric Plasma Treatment.

PubMed

Li, Chun-Yi; Liao, Ying-Chih

2016-05-11

In this study, a plasma surface modification with printing process was developed to fabricate printed flexible conductor patterns or devices directly on polydimethylsiloxane (PDMS) surface. An atmospheric plasma treatment was first used to oxidize the PDMS surface and create a hydrophilic silica surface layer, which was confirmed with photoelectron spectra. The plasma operating parameters, such as gas types and plasma powers, were optimized to obtain surface silica layers with the longest lifetime. Conductive paste with epoxy resin was screen-printed on the plasma-treated PDMS surface to fabricate flexible conductive tracks. As a result of the strong binding forces between epoxy resin and the silica surface layer, the printed patterns showed great adhesion on PDMS and were undamaged after several stringent adhesion tests. The printed conductive tracks showed strong mechanical stability and exhibited great electric conductivity under bending, twisting, and stretching conditions. Finally, a printed pressure sensor with good sensitivity and a fast response time was fabricated to demonstrate the capability of this method for the realization of printed electronic devices.

Advances and Future Challenges in Printed Batteries.

PubMed

Sousa, Ricardo E; Costa, Carlos M; Lanceros-Méndez, Senentxu

2015-11-01

There is an increasing interest in thin and flexible energy storage devices to meet modern society's needs for applications such as radio frequency sensing, interactive packaging, and other consumer products. Printed batteries comply with these requirements and are an excellent alternative to conventional batteries for many applications. Flexible and microbatteries are also included in the area of printed batteries when fabricated using printing technologies. The main characteristics, advantages, disadvantages, developments, and printing techniques of printed batteries are presented and discussed in this Review. The state-of-the-art takes into account both the research and industrial levels. On the academic level, the research progress of printed batteries is divided into lithium-ion and Zn-manganese dioxide batteries and other battery types, with emphasis on the different materials for anode, cathode, and separator as well as in the battery design. With respect to the industrial state-of-the-art, materials, device formulations, and manufacturing techniques are presented. Finally, the prospects and challenges of printed batteries are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and Fabrication of an Experimental Microheater Array Powder Sintering Printer

NASA Astrophysics Data System (ADS)

Holt, Nicholas; Zhou, Wenchao

2018-03-01

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. For MAPS to work effectively, a microscale air gap needs to be maintained between the heater array and the conductive ink. In this article, we present an experimental MAPS printer with air gap control for printing conductive circuits. First, we discuss design aspects necessary to implement MAPS. An analysis is performed to validate that the design can maintain the desired air gap between the microheaters and the sintering layer, which consists of a silver nanoparticle ink. The printer is tested by printing conductive lines on a flexible plastic substrate with silver nanoparticle ink. Results show MAPS performs on par with or better than the existing fabrication methods for printed electronics in terms of both the print quality (conductivity of the printed line) and print speed, which shows MAPS' great promise as a competitive new method for digital production of printed electronics.

Conductive Carbon Nanotube Inks for Use with Desktop Inkjet Printing Technology

NASA Technical Reports Server (NTRS)

Roberson, Luke; Williams, Martha; Tate, LaNetra; Fortier, Craig; Smith, David; Davia, Kyle; Gibson, Tracy; Snyder, Sarah

2013-01-01

Inkjet printing is a common commercial process. In addition to the familiar use in printing documents from computers, it is also used in some industrial applications. For example, wire manufacturers are required by law to print the wire type, gauge, and safety information on the exterior of each foot of manufactured wire, and this is typically done with inkjet or laser printers. The goal of this work was the creation of conductive inks that can be applied to a wire or flexible substrates via inkjet printing methods. The use of inkjet printing technology to print conductive inks has been in testing for several years. While researchers have been able to get the printing system to mechanically work, the application of conductive inks on substrates has not consistently produced adequate low resistances in the kilohm range. Conductive materials can be applied using a printer in single or multiple passes onto a substrate including textiles, polymer films, and paper. The conductive materials are composed of electrical conductors such as carbon nanotubes (including functionalized carbon nanotubes and metal-coated carbon nanotubes); graphene, a polycyclic aromatic hydrocarbon (e.g., pentacene and bisperipentacene); metal nanoparticles; inherently conductive polymers (ICP); and combinations thereof. Once the conductive materials are applied, the materials are dried and sintered to form adherent conductive materials on the substrate. For certain formulations, increased conductivity can be achieved by printing on substrates supported by low levels of magnetic field alignment. The adherent conductive materials can be used in applications such as damage detection, dust particle removal, smart coating systems, and flexible electronic circuitry. By applying alternating layers of different electrical conductors to form a layered composite material, a single homogeneous layer can be produced with improved electrical properties. It is believed that patterning alternate layers of different conductors may improve electrical pathways through alignment of the conductors and band gap optimization. One feature of this innovation is that flexible conductive traces could be accomplished with a conductive ink having a surface resistivity of less than 10 ohms/square. Another result was that a composite material comprising a mixture of carbon nanotubes and metallic nanoparticles could be applied by inkjet printing to flexible substrates, and the resulting applied material was one to two orders of magnitude more conductive than a material made by printing inks containing carbon nanotubes alone.

Knowledge Growth and Maintenance across the Lifespan: The Role of Print Exposure.

ERIC Educational Resources Information Center

Stanowich, Keith E.; And Others

1995-01-01

Examined the effects of print exposure on growth of declarative knowledge and vocabulary in 133 college students and 49 elderly adults. Compared groups on two general knowledge tasks, vocabulary, working memory, syllogistic reasoning, and print exposure. Found that exposure to print was a significant predictor of declarative and vocabulary…

Inkjet printing of conjugated polymer precursors on paper substrates for colorimetric sensing and flexible electrothermochromic display.

PubMed

Yoon, Bora; Ham, Dae-Young; Yarimaga, Oktay; An, Hyosung; Lee, Chan Woo; Kim, Jong-Man

2011-12-08

Inkjet-printable aqueous suspensions of conjugated polymer precursors are developed for fabrication of patterned color images on paper substrates. Printing of a diacetylene (DA)-surfactant composite ink on unmodified paper and photopaper, as well as on a banknote, enables generation of latent images that are transformed to blue-colored polydiacetylene (PDA) structures by UV irradiation. Both irreversible and reversible thermochromism with the PDA printed images are demonstrated and applied to flexible and disposable sensors and to displays. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Comprehensive Surface Mount Technology Solution for Integrated Circuits onto Flexible Screen Printed Electrical Interconnects

DTIC Science & Technology

2014-05-19

their acceptable thermal stability, Polyimides have established as a conventional substrate material for flexible interconnects, which can be...of the silver flake ink for the screen-printed interconnects, the assembled unit fulfills biocompatibility requirements in a limited manner ([29...30]). Even though biocompatibility of substrate [31] is fulfilled, toxicity of the insulating mask [32] and encapsulation need to be considered

Ferrocene pixels by laser-induced forward transfer: towards flexible microelectrode printing

NASA Astrophysics Data System (ADS)

Mitu, B.; Matei, A.; Filipescu, M.; Palla Papavlu, A.; Bercea, A.; Lippert, T.; Dinescu, M.

2017-03-01

The aim of this work is to demonstrate the potential of laser-induced forward transfer (LIFT) as a printing technology, alternative to standard microfabrication techniques, in the area of flexible micro-electrode fabrication. First, ferrocene thin films are deposited onto fused silica and fused silica substrates previously coated with a photodegradable polymer film (triazene polymer) by matrix assisted pulsed laser evaporation (MAPLE). The morphology and chemical structure of the ferrocene thin films deposited by MAPLE has been investigated by atomic force microscopy and Fourier transformed infrared spectroscopy, and no structural damage occurs as a result of the laser deposition. Second, LIFT is applied to print for the first time ferrocene pixels and lines onto flexible polydimethylsiloxane (PDMS) substrates. The ferrocene pixels and lines are flawlessly transferred onto the PDMS substrates in air at room temperature, without the need of additional conventional photolithography processes. We believe that these results are very promising for a variety of applications ranging from flexible electronics to lab-on-a-chip devices, MEMS, and medical implants.

A Compact Inductive Position Sensor Made by Inkjet Printing Technology on a Flexible Substrate

PubMed Central

Jeranče, Nikola; Vasiljević, Dragana; Samardžić, Nataša; Stojanović, Goran

2012-01-01

This paper describes the design, simulation and fabrication of an inductive angular position sensor on a flexible substrate. The sensor is composed of meandering silver coils printed on a flexible substrate (Kapton film) using inkjet technology. The flexibility enables that after printing in the plane, the coils could be rolled and put inside each other. By changing the angular position of the internal coil (rotor) related to the external one (stator), the mutual inductance is changed and consequently the impedance. It is possible to determine the angular position from the measured real and imaginary part of the impedance, in our case in the frequency range from 1 MHz to 10 MHz. Experimental results were compared with simulation results obtained by in-house developed software tool, and very good agreement has been achieved. Thanks to the simple design and fabrication, smaller package space requirements and weight, the presented sensor represents a cost-effective alternative to the other sensors currently used in series production applications. PMID:22438710

40 CFR 59.1 - Final determinations under Section 183(e)(3)(C) of the CAA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... furniture coatings; (b) Aerospace coatings; (c) Shipbuilding and repair coatings; (d) Lithographic printing materials; (e) Letterpress printing materials; (f) Flexible packaging printing materials; (g) Flat wood... materials; and (p) Miscellaneous industrial adhesives. [73 FR 58491, Oct. 7, 2008] ...

75 FR 21773 - Improving Government Regulations; Unified Agenda of Federal Regulatory and Deregulatory Actions

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... Register is mandated for the regulatory flexibility agendas required by the Regulatory Flexibility Act (5 U... the Agency's regulatory flexibility agenda, in accordance with the Regulatory Flexibility Act, because... Flexibility Act. Printing of these entries is limited to fields that contain information required by the...

The Effects of Blue Ink Print on Students' Memory Retention of Math Terms and Definitions.

ERIC Educational Resources Information Center

Din, Feng S.; Barnes, Kahlon

This study investigated whether students' memory retention rate improved when they were provided with blue ink printed material. A pretest, treatment, posttest with control group design was used. The participants were 93 10th and 11th grade students in algebra and geometry courses, and there were 2 classes in each course. The treatment lasted for…

Fully Printed Flexible and Stretchable Electronics

NASA Astrophysics Data System (ADS)

Zhang, Suoming

Through this thesis proposal, the author has demonstrated series of flexible or stretchable sensors including strain gauge, pressure sensors, display arrays, thin film transistors and photodetectors fabricated by a direct printing process. By adopting the novel serpentine configuration with conventional non-stretchable materials silver nanoparticles, the fully printed stretchable devices are successfully fabricated on elastomeric substrate with the demonstration of stretchable conductors that can maintain the electrical properties under strain and the strain gauge, which could be used to measure the strain in desired locations and also to monitor individual person's finger motion. And by investigating the intrinsic stretchable materials silver nanowires (AgNWs) with the conventional configuration, the fully printed stretchable conductors are achieved on various substrates including Si, glass, Polyimide, Polydimethylsiloxane (PDMS) and Very High Bond (VHB) tape with the illustration of the capacitive pressure sensor and stretchable electroluminescent displays. In addition, intrinsically stretchable thin-film transistors (TFTs) and integrated logic circuits are directly printed on elastomeric PDMS substrates. The printed devices utilize carbon nanotubes and a type of hybrid gate dielectric comprising PDMS and barium titanate (BaTiO3) nanoparticles. The BaTiO3/PDMS composite simultaneously provides high dielectric constant, superior stretchability, low leakage, as well as good printability and compatibility with the elastomeric substrate. Both TFTs and logic circuits can be stretched beyond 50% strain along either channel length or channel width directions for thousands of cycles while showing no significant degradation in electrical performance. Finally, by applying the SWNTs as the channel layer of the thin film transistor, we successfully fabricate the fully printed flexible photodetector which exhibits good electrical characteristics and the transistors exhibit good reliability under bending conditions owing to the ultrathin polyimide substrate as well as the superior mechanical flexibility of the gate dielectric and carbon nanotube network. Furthermore, we have demonstrated that by using two types of SWCNT samples with different optical absorption characteristics, the photoresponse exhibits unique wavelength selectivity, as manifested by the good correlation between the responsive wavelengths of the devices with the absorption peaks of the corresponding carbon nanotubes. All the proposed materials above together with the unique direct printing process may offer an entry into more sophisticated flexible or stretchable electronic systems with monolithically integrated sensors, actuators, and displays for real life applications.

Towards flexible asymmetric MSM structures using Si microwires through contact printing

NASA Astrophysics Data System (ADS)

Khan, S.; Lorenzelli, L.; Dahiya, R.

2017-08-01

This paper presents development of flexible metal-semiconductor-metal devices using silicon (Si) microwires. Monocrystalline Si in the shape of microwires are used which are developed through standard photolithography and etching. These microwires are assembled on secondary flexible substrates through a dry transfer printing by using a polydimethylsiloxane stamp. The conductive patterns on Si microwires are printed using a colloidal silver nanoparticles based solution and an organic conductor i.e. poly (3,4-ethylene dioxthiophene) doped with poly (styrene sulfonate). A custom developed spray coating technique is used for conductive patterns on Si microwires. A comparative study of the current-voltage (I-V) responses is carried out in flat and bent orientations as well as the response to the light illumination of the wires is explored. Current variations as high as 17.1 μA are recorded going from flat to bend conditions, while the highest I on/I off ratio i.e. 43.8 is achieved with light illuminations. The abrupt changes in the current response due to light-on/off conditions validates these devices for fast flexible photodetector switches. These devices are also evaluated based on transfer procedure i.e. flip-over and stamp-assisted transfer printing for manipulating Si microwires and their subsequent post-processing. These new developments were made to study the most feasible approach for transfer printing of Si microwires and to harvest their capabilities such as photodetection and several other applications in the shape of metal-semiconductor-metal structures.

Paper-Based Inkjet-Printed Flexible Electronic Circuits.

PubMed

Wang, Yan; Guo, Hong; Chen, Jin-Ju; Sowade, Enrico; Wang, Yu; Liang, Kun; Marcus, Kyle; Baumann, Reinhard R; Feng, Zhe-Sheng

2016-10-05

Printed flexible electronics have been widely studied for their potential use in various applications. In this paper, a simple, low-cost method of fabricating flexible electronic circuits with high conductivity of 4.0 × 10 7 S·m -1 (about 70% of the conductivity of bulk copper) is demonstrated. Teslin paper substrate is treated with stannous chloride (SnCl 2 ) colloidal solution to reduce the high ink absorption rate, and then the catalyst ink is inkjet-printed on its surface, followed by electroless deposition of copper at low temperature. In spite of the decrease in conductance to some extent, electronic circuits fabricated by this method can maintain function even under various folding angles or after repeated folding. This developed technology has great potential in a variety of applications, such as three-dimensional devices and disposable RFID tags.

Printing Electronic Components from Copper-Infused Ink and Thermoplastic Mediums

NASA Astrophysics Data System (ADS)

Flowers, Patrick F.

The demand for printable electronics has sharply increased in recent years and is projected to continue to rise. Unfortunately, electronic materials which are suitable for desired applications while being compatible with available printing techniques are still often lacking. This thesis addresses two such challenging areas. In the realm of two-dimensional ink-based printing of electronics, a major barrier to the realization of printable computers that can run programs is the lack of a solution-coatable non-volatile memory with performance metrics comparable to silicon-based devices. To address this deficiency, I developed a nonvolatile memory based on Cu-SiO2 core-shell nanowires that can be printed from solution and exhibits on-off ratios of 106, switching speeds of 50 ns, a low operating voltage of 2 V, and operates for at least 104 cycles without failure. Each of these metrics is similar to or better than Flash memory (the write speed is 20 times faster than Flash). Memory architectures based on the individual memory cells demonstrated here could enable the printing of the more complex, embedded computing devices that are expected to make up an internet of things. Recently, the exploration of three-dimensional printing techniques to fabricate electronic materials began. A suitable general-purpose conductive thermoplastic filament was not available, however. In this work I examine the current state of conductive thermoplastic filaments, including a newly-released highly conductive filament that my lab has produced which we call Electrifi. I focus on the use of dual-material fused filament fabrication (FFF) to 3D print electronic components (conductive traces, resistors, capacitors, inductors) and circuits (a fully-printed high-pass filter). The resistivity of traces printed from conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers was found to be 12, 0.78, and 0.014 ohm cm, respectively, enabling the creation of resistors with resistances spanning 3 orders of magnitude. The carbon black and graphene filaments were brittle and fractured easily, but the copper-based filament could be bent at least 500 times with little change in its resistance. Impedance measurements made on the thermoplastic filaments demonstrate that the copper-based filament had an impedance similar to a conductive PCB trace at 1 MHz. Dual material 3D printing was used to fabricate a variety of inductors and capacitors with properties that could be predictably tuned by modifying either the geometry of the components, or the materials used to fabricate the components. These resistors, capacitors, and inductors were combined to create a fully 3D printed high-pass filter with properties comparable to its conventional counterparts. The relatively low impedance of the copper-based filament enable its use to 3D print a receiver coil for wireless power transfer. We also demonstrate the ability to embed and connect surface mounted components in 3D printed objects with a low-cost ($1,000 in parts), open source dual-material 3D printer. This work thus demonstrates the potential for FFF 3D printing to create complex, three-dimensional circuits composed of either embedded or fully-printed electronic components.

Drug-printing by flexographic printing technology--a new manufacturing process for orodispersible films.

PubMed

Janssen, Eva Maria; Schliephacke, Ralf; Breitenbach, Armin; Breitkreutz, Jörg

2013-01-30

Orodispersible films (ODFs) are intended to disintegrate within seconds when placed onto the tongue. The common way of manufacturing is the solvent casting method. Flexographic printing on drug-free ODFs is introduced as a highly flexible and cost-effective alternative manufacturing method in this study. Rasagiline mesylate and tadalafil were used as model drugs. Printing of rasagiline solutions and tadalafil suspensions was feasible. Up to four printing cycles were performed. The possibility to employ several printing cycles enables a continuous, highly flexible manufacturing process, for example for individualised medicine. The obtained ODFs were characterised regarding their mechanical properties, their disintegration time, API crystallinity and homogeneity. Rasagiline mesylate did not recrystallise after the printing process. Relevant film properties were not affected by printing. Results were comparable to the results of ODFs manufactured with the common solvent casting technique, but the APIs are less stressed through mixing, solvent evaporation and heat. Further, loss of material due to cutting jumbo and daughter rolls can be reduced. Therefore, a versatile new manufacturing technology particularly for processing high-potent low-dose or heat sensitive drugs is introduced in this study. Copyright © 2012 Elsevier B.V. All rights reserved.

Preparation of solid silver nanoparticles for inkjet printed flexible electronics with high conductivity.

PubMed

Shen, Wenfeng; Zhang, Xianpeng; Huang, Qijin; Xu, Qingsong; Song, Weijie

2014-01-01

Silver nanoparticles (NPs) which could be kept in solid form and were easily stored without degeneration or oxidation at room temperature for a long period of time were synthesized by a simple and environmentally friendly wet chemistry method in an aqueous phase. Highly stable dispersions of aqueous silver NP inks, sintered at room temperature, for printing highly conductive tracks (∼8.0 μΩ cm) were prepared simply by dispersing the synthesized silver NP powder in water. These inks are stable, fairly homogeneous and suitable for a wide range of patterning techniques. The inks were successfully printed on paper and polyethylene terephthalate (PET) substrates using a common color printer. Upon annealing at 180 °C, the resistivity of the printed silver patterns decreased to 3.7 μΩ cm, which is close to twice that of bulk silver. Various factors affecting the resistivity of the printed silver patterns, such as annealing temperature and the number of printing cycles, were investigated. The resulting high conductivity of the printed silver patterns reached over 20% of the bulk silver value under ambient conditions, which enabled the fabrication of flexible electronic devices, as demonstrated by the inkjet printing of conductive circuits of LED devices.

Possible Applications of 3D Printing Technology on Textile Substrates

NASA Astrophysics Data System (ADS)

Korger, M.; Bergschneider, J.; Lutz, M.; Mahltig, B.; Finsterbusch, K.; Rabe, M.

2016-07-01

3D printing is a rapidly emerging additive manufacturing technology which can offer cost efficiency and flexibility in product development and production. In textile production 3D printing can also serve as an add-on process to apply 3D structures on textiles. In this study the low-cost fused deposition modeling (FDM) technique was applied using different thermoplastic printing materials available on the market with focus on flexible filaments such as thermoplastic elastomers (TPE) or Soft PLA. Since a good adhesion and stability of the 3D printed structures on textiles are essential, separation force and abrasion resistance tests were conducted with different kinds of printed woven fabrics demonstrating that a sufficient adhesion can be achieved. The main influencing factor can be attributed to the topography of the textile surface affected by the weave, roughness and hairiness offering formlocking connections followed by the wettability of the textile surface by the molten polymer, which depends on the textile surface energy and can be specifically controlled by washing (desizing), finishing or plasma treatment of the textile before the print. These basic adhesion mechanisms can also be considered crucial for 3D printing on knitwear.

Inkjet printed large-area flexible circuits: a simple methodology for optimizing the printing quality

NASA Astrophysics Data System (ADS)

Cheng, Tao; Wu, Youwei; Shen, Xiaoqin; Lai, Wenyong; Huang, Wei

2018-01-01

In this work, a simple methodology was developed to enhance the patterning resolution of inkjet printing, involving process optimization as well as substrate modification and treatment. The line width of the inkjet-printed silver lines was successfully reduced to 1/3 of the original value using this methodology. Large-area flexible circuits with delicate patterns and good morphology were thus fabricated. The resultant flexible circuits showed excellent electrical conductivity as low as 4.5 Ω/□ and strong tolerance to mechanical bending. The simple methodology is also applicable to substrates with various wettability, which suggests a general strategy to enhance the printing quality of inkjet printing for manufacturing high-performance large-area flexible electronics. Project supported by the National Key Basic Research Program of China (Nos. 2014CB648300, 2017YFB0404501), the National Natural Science Foundation of China (Nos. 21422402, 21674050), the Natural Science Foundation of Jiangsu Province (Nos. BK20140060, BK20130037, BK20140865, BM2012010), the Program for Jiangsu Specially-Appointed Professors (No. RK030STP15001), the Program for New Century Excellent Talents in University (No. NCET-13-0872), the NUPT "1311 Project" and Scientific Foundation (Nos. NY213119, NY213169), the Synergetic Innovation Center for Organic Electronics and Information Displays, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), the Leading Talent of Technological Innovation of National Ten-Thousands Talents Program of China, the Excellent Scientific and Technological Innovative Teams of Jiangsu Higher Education Institutions (No. TJ217038), the Program for Graduate Students Research and Innovation of Jiangsu Province (No. KYZZ16-0253), and the 333 Project of Jiangsu Province (Nos. BRA2017402, BRA2015374).

Graphene Inks with Cellulosic Dispersants: Development and Applications for Printed Electronics

NASA Astrophysics Data System (ADS)

Secor, Ethan Benjamin

Graphene offers promising opportunities for applications in printed and flexible electronic devices due to its high electrical and thermal conductivity, mechanical flexibility and strength, and chemical and environmental stability. However, scalable production and processing of graphene presents a critical technological challenge preventing the application of graphene for flexible electronic interconnects, electrochemical energy storage, and chemically robust electrical contacts. In this thesis, a promising and versatile platform for the production, patterning, and application of graphene inks is presented based on cellulosic dispersants. Graphene is produced from flake graphite using scalable liquid-phase exfoliation methods, using the polymers ethyl cellulose and nitrocellulose as multifunctional dispersing agents. These cellulose derivatives offer high colloidal stability and broadly tunable rheology for graphene dispersions, providing an effective and tunable platform for graphene ink development. Thermal or photonic annealing decomposes the polymer dispersant to yield high conductivity, flexible graphene patterns for various electronics applications. In particular, the chemical stability of graphene enables robust electrical contacts for ceramic, metallic, organic and electrolytic materials, validating the diverse applicability of graphene in printed electronics. Overall, the strategy for graphene ink design presented here offers a simple, efficient, and versatile method for integrating graphene in a wide range of printed devices and systems, providing both fundamental insight for nanomaterial ink development and realistic opportunities for practical applications.

High-Performance Screen-Printed Thermoelectric Films on Fabrics.

PubMed

Shin, Sunmi; Kumar, Rajan; Roh, Jong Wook; Ko, Dong-Su; Kim, Hyun-Sik; Kim, Sang Il; Yin, Lu; Schlossberg, Sarah M; Cui, Shuang; You, Jung-Min; Kwon, Soonshin; Zheng, Jianlin; Wang, Joseph; Chen, Renkun

2017-08-04

Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screen-printing of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi 0.5 Sb 1.5 Te 3 or n-type Bi 2 Te 2.7 Se 0.3 ), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscosity for printability at a very small concentration (0.45-0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively.

Fully printed flexible fingerprint-like three-axis tactile and slip force and temperature sensors for artificial skin.

PubMed

Harada, Shingo; Kanao, Kenichiro; Yamamoto, Yuki; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2014-12-23

A three-axis tactile force sensor that determines the touch and slip/friction force may advance artificial skin and robotic applications by fully imitating human skin. The ability to detect slip/friction and tactile forces simultaneously allows unknown objects to be held in robotic applications. However, the functionalities of flexible devices have been limited to a tactile force in one direction due to difficulties fabricating devices on flexible substrates. Here we demonstrate a fully printed fingerprint-like three-axis tactile force and temperature sensor for artificial skin applications. To achieve economic macroscale devices, these sensors are fabricated and integrated using only printing methods. Strain engineering enables the strain distribution to be detected upon applying a slip/friction force. By reading the strain difference at four integrated force sensors for a pixel, both the tactile and slip/friction forces can be analyzed simultaneously. As a proof of concept, the high sensitivity and selectivity for both force and temperature are demonstrated using a 3×3 array artificial skin that senses tactile, slip/friction, and temperature. Multifunctional sensing components for a flexible device are important advances for both practical applications and basic research in flexible electronics.

Direct printing and reduction of graphite oxide for flexible supercapacitors

NASA Astrophysics Data System (ADS)

Jung, Hanyung; Ve Cheah, Chang; Jeong, Namjo; Lee, Junghoon

2014-08-01

We report direct printing and photo-thermal reduction of graphite oxide (GO) to obtain a highly porous pattern of interdigitated electrodes, leading to a supercapacitor on a flexible substrate. Key parameters optimized include the amount of GO delivered, the suitable photo-thermal energy level for effective flash reduction, and the substrate properties for appropriate adhesion after reduction. Tests with supercapacitors based on the printed-reduced GO showed performance comparable with commercial supercapacitors: the energy densities were 1.06 and 0.87 mWh/cm3 in ionic and organic electrolytes, respectively. The versatility in the architecture and choice of substrate makes this material promising for smart power applications.

Department of Defense Semiannual Regulatory Agenda

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... regulatory flexibility agendas required by the Regulatory Flexibility Act (5 U.S.C. 602), the Department of Defense's printed agenda entries include only: (1) Rules that are in the Agency's regulatory flexibility agenda, in accordance with the Regulatory Flexibility Act, because they are likely to have a significant...

Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

DOE PAGES

Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; ...

2015-12-31

The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

Flexible integrated diode-transistor logic (DTL) driving circuits based on printed carbon nanotube thin film transistors with low operation voltage.

PubMed

Liu, Tingting; Zhao, Jianwen; Xu, Weiwei; Dou, Junyan; Zhao, Xinluo; Deng, Wei; Wei, Changting; Xu, Wenya; Guo, Wenrui; Su, Wenming; Jie, Jiansheng; Cui, Zheng

2018-01-03

Fabrication and application of hybrid functional circuits have become a hot research topic in the field of printed electronics. In this study, a novel flexible diode-transistor logic (DTL) driving circuit is proposed, which was fabricated based on a light emitting diode (LED) integrated with printed high-performance single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs). The LED, which is made of AlGaInP on GaAs, is commercial off-the-shelf, which could generate free electrical charges upon white light illumination. Printed top-gate TFTs were made on a PET substrate by inkjet printing high purity semiconducting SWCNTs (sc-SWCNTs) ink as the semiconductor channel materials, together with printed silver ink as the top-gate electrode and printed poly(pyromellitic dianhydride-co-4,4'-oxydianiline) (PMDA/ODA) as gate dielectric layer. The LED, which is connected to the gate electrode of the TFT, generated electrical charge when illuminated, resulting in biased gate voltage to control the TFT from "ON" status to "OFF" status. The TFTs with a PMDA/ODA gate dielectric exhibited low operating voltages of ±1 V, a small subthreshold swing of 62-105 mV dec -1 and ON/OFF ratio of 10 6 , which enabled DTL driving circuits to have high ON currents, high dark-to-bright current ratios (up to 10 5 ) and good stability under repeated white light illumination. As an application, the flexible DTL driving circuit was connected to external quantum dot LEDs (QLEDs), demonstrating its ability to drive and to control the QLED.

Advances in Flexible Hybrid Electronics Reliability

DTIC Science & Technology

2017-03-01

Advances in Flexible Hybrid Electronics Reliability Douglas R. Hackler, Richard L. Chaney, Brian N. Meek, Darrell E. Leber, Seth D. Leija, Kelly J...www.americansemi.com Abstract: Flexible Hybrid Electronics combine the best characteristics of printed electronics and silicon ICs to create high performance...presented for flexible hybrid electronics systems. Keywords: FleX; flexible; flexible hybrid electronics ; FHE; Silicon-on-Polymer Introduction

Screen-printed flexible MRI receive coils

PubMed Central

Corea, Joseph R.; Flynn, Anita M.; Lechêne, Balthazar; Scott, Greig; Reed, Galen D.; Shin, Peter J.; Lustig, Michael; Arias, Ana C.

2016-01-01

Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18 mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners. PMID:26961073

[Flexible print circuit technology application in biomedical engineering].

PubMed

Jiang, Lihua; Cao, Yi; Zheng, Xiaolin

2013-06-01

Flexible print circuit (FPC) technology has been widely applied in variety of electric circuits with high precision due to its advantages, such as low-cost, high specific fabrication ability, and good flexibility, etc. Recently, this technology has also been used in biomedical engineering, especially in the development of microfluidic chip and microelectrode array. The high specific fabrication can help making microelectrode and other micro-structure equipment. And good flexibility allows the micro devices based on FPC technique to be easily packaged with other parts. In addition, it also reduces the damage of microelectrodes to the tissue. In this paper, the application of FPC technology in biomedical engineering is introduced. Moreover, the important parameters of FPC technique and the development trend of prosperous applications is also discussed.

Transfer printing of thermoreversible ion gels for flexible electronics.

PubMed

Lee, Keun Hyung; Zhang, Sipei; Gu, Yuanyan; Lodge, Timothy P; Frisbie, C Daniel

2013-10-09

Thermally assisted transfer printing was employed to pattern thin films of high capacitance ion gels on polyimide, poly(ethylene terephthalate), and SiO2 substrates. The ion gels consisted of 20 wt % block copolymer poly(styrene-b-ethylene oxide-b-styrene and 80 wt % ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)amide. Patterning resolution was on the order of 10 μm. Importantly, ion gels containing the block polymer with short PS end blocks (3.4 kg/mol) could be transfer-printed because of thermoreversible gelation that enabled intimate gel-substrate contact at 100 °C, while gels with long PS blocks (11 kg/mol) were not printable at the same temperature due to poor wetting contact between the gel and substrates. By using printed ion gels as high-capacitance gate insulators, electrolyte-gated thin-film transistors were fabricated that operated at low voltages (<1 V) with high on/off current ratios (∼10(5)). Statistical analysis of carrier mobility, turn-on voltage, and on/off ratio for an array of printed transistors demonstrated the excellent reproducibility of the printing technique. The results show that transfer printing is an attractive route to pattern high-capacitance ion gels for flexible thin-film devices.

Inkjet printed graphene-based field-effect transistors on flexible substrate

NASA Astrophysics Data System (ADS)

Monne, Mahmuda Akter; Enuka, Evarestus; Wang, Zhuo; Chen, Maggie Yihong

2017-08-01

This paper presents the design and fabrication of inkjet printed graphene field-effect transistors (GFETs). The inkjet printed GFET is fabricated on a DuPont Kapton FPC Polyimide film with a thickness of 5 mill and dielectric constant of 3.9 by using a Fujifilm Dimatix DMP-2831 materials deposition system. A layer by layer 3D printing technique is deployed with an initial printing of source and drain by silver nanoparticle ink. Then graphene active layer doped with molybdenum disulfide (MoS2) monolayer/multilayer dispersion, is printed onto the surface of substrate covering the source and drain electrodes. High capacitance ion gel is adopted as the dielectric material due to the high dielectric constant. Then the dielectric layer is then covered with silver nanoparticle gate electrode. Characterization of GFET has been done at room temperature (25°C) using HP-4145B semiconductor parameter analyzer (Hewlett-Packard). The characterization result shows for a voltage sweep from -2 volts to 2 volts, the drain current changes from 949 nA to 32.3 μA and the GFET achieved an on/off ratio of 38:1, which is a milestone for inkjet printed flexible graphene transistor.

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

NASA Astrophysics Data System (ADS)

de Vos, Marc; Torah, Russel; Tudor, John

2016-04-01

Flexible electroluminescent (EL) lamps are fabricated onto woven textiles using a novel dispenser printing process. Dispenser printing utilizes pressurized air to deposit ink onto a substrate through a syringe and nozzle. This work demonstrates the first use of this technology to fabricate EL lamps. The luminance of the dispenser printed EL lamps is compared to screen-printed EL lamps, both printed on textile, and also commercial EL lamps on polyurethane film. The dispenser printed lamps are shown to have a 1.5 times higher luminance than the best performing commercially available lamp, and have a comparable performance to the screen-printed lamps.

Roll-To-Roll Printing of Meter-Scale Composite Transparent Electrodes with Optimized Mechanical and Optical Properties for Photoelectronics.

PubMed

Meng, Xiangchuan; Hu, Xiaotian; Yang, Xia; Yin, Jingping; Wang, Qingxia; Huang, Liqiang; Yu, Zoukangning; Hu, Ting; Tan, Licheng; Zhou, Weihua; Chen, Yiwang

2018-03-14

Flexible transparent electrodes are an indispensable component for flexible optoelectronic devices. In this work, the meter-scale composite transparent electrodes (CTEs) composed of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and Ag grid/polyethylene terephthalate (PET) with optimized mechanical and optical properties are demonstrated by slot-die roll-to-roll technique with solution printing method under a low cost ($15-20 per square meter), via control of the viscosity and surface energy of PEDOT:PSS ink as well as the printing parameters. The CTEs show excellent flexibility remaining 98% of the pristine value after bending 2000 times under various bending situations, and the square resistance ( R s ) of CTEs can be reduced to 4.5-5.0 Ω/sq with an appropriate transmittance. Moreover, the optical performances, such as haze, extinction coefficient, and refractive index, are investigated, as compared with indium tin oxide/PET, which are potential for the inexpensive optoelectronic flexible devices. The CTEs could be successfully employed in polymer solar cells with different areas, showing a maximal power conversion efficiency of 8.08%.

High-Performance Screen-Printed Thermoelectric Films on Fabrics

DOE PAGES

Shin, Sunmi; Kumar, Rajan; Roh, Jong Wook; ...

2017-08-04

Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screenprinting of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi 0.5Sb 1.5Te 3 or n-type Bi 2Te 2.7Se 0.3), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscositymore » for printability at a very small concentration (0.45–0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively.« less

High-Performance Screen-Printed Thermoelectric Films on Fabrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Sunmi; Kumar, Rajan; Roh, Jong Wook

Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screenprinting of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi 0.5Sb 1.5Te 3 or n-type Bi 2Te 2.7Se 0.3), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscositymore » for printability at a very small concentration (0.45–0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively.« less

Printed Graphene Derivative Circuits as Passive Electrical Filters

PubMed Central

Sinar, Dogan

2018-01-01

The objective of this study is to inkjet print resistor-capacitor (RC) low pass electrical filters, using a novel water-based cellulose graphene ink, and compare the voltage-frequency and transient behavior to equivalent circuits constructed from discrete passive components. The synthesized non-toxic graphene-carboxymethyl cellulose (G-CMC) ink is deposited on mechanically flexible polyimide substrates using a customized printer that dispenses functionalized aqueous solutions. The design of the printed first-order and second-order low-pass RC filters incorporate resistive traces and interdigitated capacitors. Low pass filter characteristics, such as time constant, cut-off frequency and roll-off rate, are determined for comparative analysis. Experiments demonstrate that for low frequency applications (<100 kHz) the printed graphene derivative circuits performed as well as the circuits constructed from discrete resistors and capacitors for both low pass filter and RC integrator applications. The impact of mechanical stress due to bending on the electrical performance of the flexible printed circuits is also investigated. PMID:29473890

Highly Sensitive Flexible Pressure Sensors Based on Printed Organic Transistors with Centro-Apically Self-Organized Organic Semiconductor Microstructures.

PubMed

Yeo, So Young; Park, Sangsik; Yi, Yeon Jin; Kim, Do Hwan; Lim, Jung Ah

2017-12-13

A highly sensitive pressure sensor based on printed organic transistors with three-dimensionally self-organized organic semiconductor microstructures (3D OSCs) was demonstrated. A unique organic transistor with semiconductor channels positioned at the highest summit of printed cylindrical microstructures was achieved simply by printing an organic semiconductor and polymer blend on the plastic substrate without the use of additional etching or replication processes. A combination of the printed organic semiconductor microstructure and an elastomeric top-gate dielectric resulted in a highly sensitive organic field-effect transistor (FET) pressure sensor with a high pressure sensitivity of 1.07 kPa -1 and a rapid response time of <20 ms with a high reliability over 1000 cycles. The flexibility and high performance of the 3D OSC FET pressure sensor were exploited in the successful application of our sensors to real-time monitoring of the radial artery pulse, which is useful for healthcare monitoring, and to touch sensing in the e-skin of a realistic prosthetic hand.

Fabrication of Ultra-Thin Printed Organic TFT CMOS Logic Circuits Optimized for Low-Voltage Wearable Sensor Applications.

PubMed

Takeda, Yasunori; Hayasaka, Kazuma; Shiwaku, Rei; Yokosawa, Koji; Shiba, Takeo; Mamada, Masashi; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

2016-05-09

Ultrathin electronic circuits that can be manufactured by using conventional printing technologies are key elements necessary to realize wearable health sensors and next-generation flexible electronic devices. Due to their low level of power consumption, complementary (CMOS) circuits using both types of semiconductors can be easily employed in wireless devices. Here, we describe ultrathin CMOS logic circuits, for which not only the source/drain electrodes but also the semiconductor layers were printed. Both p-type and n-type organic thin film transistor devices were employed in a D-flip flop circuit in the newly developed stacked structure and exhibited excellent electrical characteristics, including good carrier mobilities of 0.34 and 0.21 cm(2) V(-1) sec(-1), and threshold voltages of nearly 0 V with low operating voltages. These printed organic CMOS D-flip flop circuits exhibit operating frequencies of 75 Hz and demonstrate great potential for flexible and printed electronics technology, particularly for wearable sensor applications with wireless connectivity.

Printed Graphene Derivative Circuits as Passive Electrical Filters.

PubMed

Sinar, Dogan; Knopf, George K

2018-02-23

The objective of this study is to inkjet print resistor-capacitor ( RC ) low pass electrical filters, using a novel water-based cellulose graphene ink, and compare the voltage-frequency and transient behavior to equivalent circuits constructed from discrete passive components. The synthesized non-toxic graphene-carboxymethyl cellulose (G-CMC) ink is deposited on mechanically flexible polyimide substrates using a customized printer that dispenses functionalized aqueous solutions. The design of the printed first-order and second-order low-pass RC filters incorporate resistive traces and interdigitated capacitors. Low pass filter characteristics, such as time constant, cut-off frequency and roll-off rate, are determined for comparative analysis. Experiments demonstrate that for low frequency applications (<100 kHz) the printed graphene derivative circuits performed as well as the circuits constructed from discrete resistors and capacitors for both low pass filter and RC integrator applications. The impact of mechanical stress due to bending on the electrical performance of the flexible printed circuits is also investigated.

Fabrication of Ultra-Thin Printed Organic TFT CMOS Logic Circuits Optimized for Low-Voltage Wearable Sensor Applications

PubMed Central

Takeda, Yasunori; Hayasaka, Kazuma; Shiwaku, Rei; Yokosawa, Koji; Shiba, Takeo; Mamada, Masashi; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

2016-01-01

Ultrathin electronic circuits that can be manufactured by using conventional printing technologies are key elements necessary to realize wearable health sensors and next-generation flexible electronic devices. Due to their low level of power consumption, complementary (CMOS) circuits using both types of semiconductors can be easily employed in wireless devices. Here, we describe ultrathin CMOS logic circuits, for which not only the source/drain electrodes but also the semiconductor layers were printed. Both p-type and n-type organic thin film transistor devices were employed in a D-flip flop circuit in the newly developed stacked structure and exhibited excellent electrical characteristics, including good carrier mobilities of 0.34 and 0.21 cm2 V−1 sec−1, and threshold voltages of nearly 0 V with low operating voltages. These printed organic CMOS D-flip flop circuits exhibit operating frequencies of 75 Hz and demonstrate great potential for flexible and printed electronics technology, particularly for wearable sensor applications with wireless connectivity. PMID:27157914

Active origami by 4D printing

NASA Astrophysics Data System (ADS)

Ge, Qi; Dunn, Conner K.; Qi, H. Jerry; Dunn, Martin L.

2014-09-01

Recent advances in three dimensional (3D) printing technology that allow multiple materials to be printed within each layer enable the creation of materials and components with precisely controlled heterogeneous microstructures. In addition, active materials, such as shape memory polymers, can be printed to create an active microstructure within a solid. These active materials can subsequently be activated in a controlled manner to change the shape or configuration of the solid in response to an environmental stimulus. This has been termed 4D printing, with the 4th dimension being the time-dependent shape change after the printing. In this paper, we advance the 4D printing concept to the design and fabrication of active origami, where a flat sheet automatically folds into a complicated 3D component. Here we print active composites with shape memory polymer fibers precisely printed in an elastomeric matrix and use them as intelligent active hinges to enable origami folding patterns. We develop a theoretical model to provide guidance in selecting design parameters such as fiber dimensions, hinge length, and programming strains and temperature. Using the model, we design and fabricate several active origami components that assemble from flat polymer sheets, including a box, a pyramid, and two origami airplanes. In addition, we directly print a 3D box with active composite hinges and program it to assume a temporary flat shape that subsequently recovers to the 3D box shape on demand.

Translational Approaches Targeting Reconsolidation

PubMed Central

Kroes, Marijn C.W.; LeDoux, Joseph E.; Phelps, Elizabeth A.

2017-01-01

Maladaptive learned responses and memories contribute to psychiatric disorders that constitute a significant socio-economic burden. Primary treatment methods teach patients to inhibit maladaptive responses, but do not get rid of the memory itself, which explains why many patients experience a return of symptoms even after initially successful treatment. This highlights the need to discover more persistent and robust techniques to diminish maladaptive learned behaviours. One potentially promising approach is to alter the original memory, as opposed to inhibiting it, by targeting memory reconsolidation. Recent research shows that reactivating an old memory results in a period of memory flexibility and requires restorage, or reconsolidation, for the memory to persist. This reconsolidation period allows a window for modification of a specific old memory. Renewal of memory flexibility following reactivation holds great clinical potential as it enables targeting reconsolidation and changing of specific learned responses and memories that contribute to maladaptive mental states and behaviours. Here, we will review translational research on non-human animals, healthy human subjects, and clinical populations aimed at altering memories by targeting reconsolidation using biological treatments (electrical stimulation, noradrenergic antagonists) or behavioural interference (reactivation–extinction paradigm). Both approaches have been used successfully to modify aversive and appetitive memories, yet effectiveness in treating clinical populations has been limited. We will discuss that memory flexibility depends on the type of memory tested and the brain regions that underlie specific types of memory. Further, when and how we can most effectively reactivate a memory and induce flexibility is largely unclear. Finally, the development of drugs that can target reconsolidation and are safe for use in humans would optimize cross-species translations. Increasing the understanding of the mechanism and limitations of memory flexibility upon reactivation should help optimize efficacy of treatments for psychiatric patients. PMID:27240676

Flexible and twistable non-volatile memory cell array with all-organic one diode-one resistor architecture.

PubMed

Ji, Yongsung; Zeigler, David F; Lee, Dong Su; Choi, Hyejung; Jen, Alex K-Y; Ko, Heung Cho; Kim, Tae-Wook

2013-01-01

Flexible organic memory devices are one of the integral components for future flexible organic electronics. However, high-density all-organic memory cell arrays on malleable substrates without cross-talk have not been demonstrated because of difficulties in their fabrication and relatively poor performances to date. Here we demonstrate the first flexible all-organic 64-bit memory cell array possessing one diode-one resistor architectures. Our all-organic one diode-one resistor cell exhibits excellent rewritable switching characteristics, even during and after harsh physical stresses. The write-read-erase-read output sequence of the cells perfectly correspond to the external pulse signal regardless of substrate deformation. The one diode-one resistor cell array is clearly addressed at the specified cells and encoded letters based on the standard ASCII character code. Our study on integrated organic memory cell arrays suggests that the all-organic one diode-one resistor cell architecture is suitable for high-density flexible organic memory applications in the future.

Interfacial engineering of printable bottom back metal electrodes for full-solution processed flexible organic solar cells

NASA Astrophysics Data System (ADS)

Zhen, Hongyu; Li, Kan; Zhang, Yaokang; Chen, Lina; Niu, Liyong; Wei, Xiaoling; Fang, Xu; You, Peng; Liu, Zhike; Wang, Dongrui; Yan, Feng; Zheng, Zijian

2018-01-01

Printing of metal bottom back electrodes of flexible organic solar cells (FOSCs) at low temperature is of great significance to realize the full-solution fabrication technology. However, this has been difficult to achieve because often the interfacial properties of those printed electrodes, including conductivity, roughness, work function, optical and mechanical flexibility, cannot meet the device requirement at the same time. In this work, we fabricate printed Ag and Cu bottom back cathodes by a low-temperature solution technique named polymer-assisted metal deposition (PAMD) on flexible PET substrates. Branched polyethylenimine (PEI) and ZnO thin films are used as the interface modification layers (IMLs) of these cathodes. Detailed experimental studies on the electrical, mechanical, and morphological properties, and simulation study on the optical properties of these IMLs are carried out to understand and optimize the interface of printed cathodes. We demonstrate that the highest power conversion efficiency over 3.0% can be achieved from a full-solution processed OFSC with the device structure being PAMD-Ag/PEI/P3HT:PC61BM/PH1000. This device also acquires remarkable stability upon repeating bending tests. Project supported by the Research Grant Council of Hong Kong (No. PolyUC5015-15G), the Hong Kong Polytechnic University (No. G-SB06), and the National Natural Science Foundation of China (Nos. 21125316, 21434009, 51573026).

Battery-Free Smart Sock for Abnormal Relative Plantar Pressure Monitoring.

PubMed

Lin, Xiaoyou; Seet, Boon-Chong

2017-04-01

This paper presents a new design of a wearable plantar pressure monitoring system in the form of a smart sock for sensing abnormal relative pressure changes. One advantage of this approach is that with a battery-free design, this system can be powered solely by radio frequency (RF) energy harvested from a radio frequency identification (RFID) reader unit hosted on a smartphone of the wearer. At the same time, this RFID reader can read foot pressure values from an embedded sensor-tag in the sock. A pressure sensing matrix made of conductive fabric and flexible piezo-resistive material is integrated into the sock during the knitting process. Sensed foot pressures are digitized and stored in the memory of a sensor-tag, thus allowing relative foot pressure values to be tracked. The control unit of the smart sock is assembled on a flexible printed circuit board (FPC) that can be strapped to the lower limb and detached easily when it is not in use. Experiments show that the system can operate reliably in both tasks of RF energy harvesting and pressure measurement.

Structural and electrical properties of Ag grid/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) coatings for diode application through advanced printing technology.

PubMed

Duraisamy, Navaneethan; Ponniah, Ganeshthangaraj; Jo, Jeongdai; Choi, Kyung-Hyun

2013-08-01

This paper is focused on printed techniques for the fabrication of hybrid structure of silver (Ag) grid/poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT:PSS) on polyethylene terepthalate (PET) as a flexible substrate. Ag grid has been printed on PET substrate by using gravure offset printing process, followed by PEDOT:PSS thin film deposition on Ag grid through electrohydrodynamic atomization (EHDA) technique. The important parameters for achieving uniform hybrid structure of Ag grid/PEDOT:PSS through printed techniques have been clearly discussed. Field emission scanning electron microscope studies revealed the uniformity of printed Ag grid with homogeneous deposition of PEDOT:PSS on Ag grid. The optical properties of Ag grid/PEDOT:PSS were measured by UV-visible spectroscopy, which showed nearly 80-82% of transparency in the visible region and it was nearly same as PEDOT:PSS thin film on PET substrate. Current-voltage (I-V) analysis of fabricated hybrid device by using printed Ag grid/PEDOT:PSS as a bottom electrode showed good rectifying behavior with possible interfacial mechanisms. Capacitance-voltage (C-V) analysis was carried over different frequencies. These results suggest that fabrication of hybrid structure through printed techniques will play a significant role in mass production of printed electronic devices for commercial application by using flexible substrate.

31. Photocopy of photograph (original print in Helgesen Collection) Photographer ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. Photocopy of photograph (original print in Helgesen Collection) Photographer unknown 1928 MEN'S MEZZANINE SMOKING ROOM - B. F. Keith Memorial Theatre, 539 Washington Street, Boston, Suffolk County, MA

Direct printing and reduction of graphite oxide for flexible supercapacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Hanyung; Ve Cheah, Chang; Jeong, Namjo

2014-08-04

We report direct printing and photo-thermal reduction of graphite oxide (GO) to obtain a highly porous pattern of interdigitated electrodes, leading to a supercapacitor on a flexible substrate. Key parameters optimized include the amount of GO delivered, the suitable photo-thermal energy level for effective flash reduction, and the substrate properties for appropriate adhesion after reduction. Tests with supercapacitors based on the printed-reduced GO showed performance comparable with commercial supercapacitors: the energy densities were 1.06 and 0.87 mWh/cm{sup 3} in ionic and organic electrolytes, respectively. The versatility in the architecture and choice of substrate makes this material promising for smart powermore » applications.« less

Rapid formation and flexible expression of memories of subliminal word pairs.

PubMed

Reber, Thomas P; Henke, Katharina

2011-01-01

Our daily experiences are incidentally and rapidly encoded as episodic memories. Episodic memories consist of numerous associations (e.g., who gave what to whom where and when) that can be expressed flexibly in new situations. Key features of episodic memory are speed of encoding, its associative nature, and its representational flexibility. Another defining feature of human episodic memory has been consciousness of encoding/retrieval. Here, we show that humans can rapidly form associations between subliminal words and minutes later retrieve these associations even if retrieval words were conceptually related to, but different from encoding words. Because encoding words were presented subliminally, associative encoding, and retrieval were unconscious. Unconscious association formation and retrieval were dependent on a preceding understanding of task principles. We conclude that key computations underlying episodic memory - rapid encoding and flexible expression of associations - can operate outside consciousness.

75 FR 79751 - Improving Government Regulations; Unified Agenda of Federal Regulatory and Deregulatory Actions

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-20

... regulatory flexibility agendas required by the Regulatory Flexibility Act (5 U.S.C. 602), the Department of Defense's printed agenda entries include only: (1) Rules that are in the Agency's regulatory flexibility agenda, in accordance with the Regulatory Flexibility Act, because they are likely to have a significant...

Working Memory and Cognitive Flexibility Mediates Visuoconstructional Abilities in Older Adults with Heterogeneous Cognitive Ability.

PubMed

Ávila, Rafaela T; de Paula, Jonas J; Bicalho, Maria A; Moraes, Edgar N; Nicolato, Rodrigo; Malloy-Diniz, Leandro F; Diniz, Breno S

2015-05-01

Previous studies suggest that executive functions influence the performance on visuoconstructional tasks. This study aims to investigate whether the relationship between planning ability and the copy of complex figures is mediated by distinct components of executive functions (i.e., working memory, inhibitory control and cognitive flexibility). We included a 129 older adults with Alzheimer's disease (n=36, AD), mild cognitive impairment (MCI, n=67), and with no evidence of cognitive impairment (controls, n=26). We evaluated the mediation effect of planning abilities, working memory, cognitive flexibility and inhibitory control on visuoconstructional tasks using a multiple mediation models. We found a significant direct effect of planning on visuoconstructional abilities and a partial mediation effect of working memory and cognitive flexibility on visuoconstructional abilities. The present results indicate that the performance on visuoconstructional task is mediated by multiple interrelated executive functions components, in particular working memory and cognitive flexibility.

Interactive digital image manipulation system

NASA Technical Reports Server (NTRS)

Henze, J.; Dezur, R.

1975-01-01

The system is designed for manipulation, analysis, interpretation, and processing of a wide variety of image data. LANDSAT (ERTS) and other data in digital form can be input directly into the system. Photographic prints and transparencies are first converted to digital form with an on-line high-resolution microdensitometer. The system is implemented on a Hewlett-Packard 3000 computer with 128 K bytes of core memory and a 47.5 megabyte disk. It includes a true color display monitor, with processing memories, graphics overlays, and a movable cursor. Image data formats are flexible so that there is no restriction to a given set of remote sensors. Conversion between data types is available to provide a basis for comparison of the various data. Multispectral data is fully supported, and there is no restriction on the number of dimensions. In this way multispectral data collected at more than one point in time may simply be treated as a data collected with twice (three times, etc.) the number of sensors. There are various libraries of functions available to the user: processing functions, display functions, system functions, and earth resources applications functions.

Thermorheological characteristics and comparison of shape memory polymers fabricated by novel 3D printing technique

NASA Astrophysics Data System (ADS)

Hassan, Rizwan Ul; Jo, Soohwan; Seok, Jongwon

The feasibility of fabrication of shape memory polymers (SMPs) was investigated using a customized 3-dimensional (3D) printing technique with an excellent resolution that could be less than 100 microns. The thermorheological effects of SMPs were adjusted by contact and non-contact triggering, which led to the respective excellent shape recoveries of 100% and 99.89%. Thermogravimetric analyses of SMPs resulted in a minor weight loss, thereby revealing good thermal stability at higher temperatures. The viscoelastic properties of SMPs were measured using dynamic mechanical analyses, exhibiting increased viscous and elastic characteristics. Mechanical strength, thermal stability and viscoelastic properties, of the two SMPs were compared [di(ethylene) glycol dimethacrylate (DEGDMA) and poly (ethylene glycol) dimethacrylate (PEGDMA)] to investigate the shape memory behavior. This novel 3D printing technique can be used as a promising method for fabricating smart materials with increased accuracy in a cost-effective manner.

Carbon Nanotube Flexible and Stretchable Electronics

NASA Astrophysics Data System (ADS)

Cai, Le; Wang, Chuan

2015-08-01

The low-cost and large-area manufacturing of flexible and stretchable electronics using printing processes could radically change people's perspectives on electronics and substantially expand the spectrum of potential applications. Examples range from personalized wearable electronics to large-area smart wallpapers and from interactive bio-inspired robots to implantable health/medical apparatus. Owing to its one-dimensional structure and superior electrical property, carbon nanotube is one of the most promising material platforms for flexible and stretchable electronics. Here in this paper, we review the recent progress in this field. Applications of single-wall carbon nanotube networks as channel semiconductor in flexible thin-film transistors and integrated circuits, as stretchable conductors in various sensors, and as channel material in stretchable transistors will be discussed. Lastly, state-of-the-art advancement on printing process, which is ideal for large-scale fabrication of flexible and stretchable electronics, will also be reviewed in detail.

Carbon Nanotube Flexible and Stretchable Electronics.

PubMed

Cai, Le; Wang, Chuan

2015-12-01

The low-cost and large-area manufacturing of flexible and stretchable electronics using printing processes could radically change people's perspectives on electronics and substantially expand the spectrum of potential applications. Examples range from personalized wearable electronics to large-area smart wallpapers and from interactive bio-inspired robots to implantable health/medical apparatus. Owing to its one-dimensional structure and superior electrical property, carbon nanotube is one of the most promising material platforms for flexible and stretchable electronics. Here in this paper, we review the recent progress in this field. Applications of single-wall carbon nanotube networks as channel semiconductor in flexible thin-film transistors and integrated circuits, as stretchable conductors in various sensors, and as channel material in stretchable transistors will be discussed. Lastly, state-of-the-art advancement on printing process, which is ideal for large-scale fabrication of flexible and stretchable electronics, will also be reviewed in detail.

Logic circuits composed of flexible carbon nanotube thin-film transistor and ultra-thin polymer gate dielectric

PubMed Central

Lee, Dongil; Yoon, Jinsu; Lee, Juhee; Lee, Byung-Hyun; Seol, Myeong-Lok; Bae, Hagyoul; Jeon, Seung-Bae; Seong, Hyejeong; Im, Sung Gap; Choi, Sung-Jin; Choi, Yang-Kyu

2016-01-01

Printing electronics has become increasingly prominent in the field of electronic engineering because this method is highly efficient at producing flexible, low-cost and large-scale thin-film transistors. However, TFTs are typically constructed with rigid insulating layers consisting of oxides and nitrides that are brittle and require high processing temperatures, which can cause a number of problems when used in printed flexible TFTs. In this study, we address these issues and demonstrate a method of producing inkjet-printed TFTs that include an ultra-thin polymeric dielectric layer produced by initiated chemical vapor deposition (iCVD) at room temperature and highly purified 99.9% semiconducting carbon nanotubes. Our integrated approach enables the production of flexible logic circuits consisting of CNT-TFTs on a polyethersulfone (PES) substrate that have a high mobility (up to 9.76 cm2 V−1 sec−1), a low operating voltage (less than 4 V), a high current on/off ratio (3 × 104), and a total device yield of 90%. Thus, it should be emphasized that this study delineates a guideline for the feasibility of producing flexible CNT-TFT logic circuits with high performance based on a low-cost and simple fabrication process. PMID:27184121

Logic circuits composed of flexible carbon nanotube thin-film transistor and ultra-thin polymer gate dielectric

NASA Astrophysics Data System (ADS)

Lee, Dongil; Yoon, Jinsu; Lee, Juhee; Lee, Byung-Hyun; Seol, Myeong-Lok; Bae, Hagyoul; Jeon, Seung-Bae; Seong, Hyejeong; Im, Sung Gap; Choi, Sung-Jin; Choi, Yang-Kyu

2016-05-01

Printing electronics has become increasingly prominent in the field of electronic engineering because this method is highly efficient at producing flexible, low-cost and large-scale thin-film transistors. However, TFTs are typically constructed with rigid insulating layers consisting of oxides and nitrides that are brittle and require high processing temperatures, which can cause a number of problems when used in printed flexible TFTs. In this study, we address these issues and demonstrate a method of producing inkjet-printed TFTs that include an ultra-thin polymeric dielectric layer produced by initiated chemical vapor deposition (iCVD) at room temperature and highly purified 99.9% semiconducting carbon nanotubes. Our integrated approach enables the production of flexible logic circuits consisting of CNT-TFTs on a polyethersulfone (PES) substrate that have a high mobility (up to 9.76 cm2 V-1 sec-1), a low operating voltage (less than 4 V), a high current on/off ratio (3 × 104), and a total device yield of 90%. Thus, it should be emphasized that this study delineates a guideline for the feasibility of producing flexible CNT-TFT logic circuits with high performance based on a low-cost and simple fabrication process.

Recent developments and directions in printed nanomaterials

NASA Astrophysics Data System (ADS)

Choi, Hyung Woo; Zhou, Tianlei; Singh, Madhusudan; Jabbour, Ghassan E.

2015-02-01

In this review, we survey several recent developments in printing of nanomaterials for contacts, transistors, sensors of various kinds, light-emitting diodes, solar cells, memory devices, and bone and organ implants. The commonly used nanomaterials are classified according to whether they are conductive, semiconducting/insulating or biological in nature. While many printing processes are covered, special attention is paid to inkjet printing and roll-to-roll printing in light of their complexity and popularity. In conclusion, we present our view of the future development of this field.

Triple shape memory polymers by 4D printing

NASA Astrophysics Data System (ADS)

Bodaghi, M.; Damanpack, A. R.; Liao, W. H.

2018-06-01

This article aims at introducing triple shape memory polymers (SMPs) by four-dimensional (4D) printing technology and shaping adaptive structures for mechanical/bio-medical devices. The main approach is based on arranging hot–cold programming of SMPs with fused decomposition modeling technology to engineer adaptive structures with triple shape memory effect (SME). Experiments are conducted to characterize elasto-plastic and hyper-elastic thermo-mechanical material properties of SMPs in low and high temperatures at large deformation regime. The feasibility of the dual and triple SMPs with self-bending features is demonstrated experimentally. It is advantageous in situations either where it is desired to perform mechanical manipulations on the 4D printed objects for specific purposes or when they experience cold programming inevitably before activation. A phenomenological 3D constitutive model is developed for quantitative understanding of dual/triple SME of SMPs fabricated by 4D printing in the large deformation range. Governing equations of equilibrium are established for adaptive structures on the basis of the nonlinear Green–Lagrange strains. They are then solved by developing a finite element approach along with an elastic-predictor plastic-corrector return map procedure accomplished by the Newton–Raphson method. The computational tool is applied to simulate dual/triple SMP structures enabled by 4D printing and explore hot–cold programming mechanisms behind material tailoring. It is shown that the 4D printed dual/triple SMPs have great potential in mechanical/bio-medical applications such as self-bending gripers/stents and self-shrinking/tightening staples.

Inkjet Printing of Carbon Nanotubes

PubMed Central

Tortorich, Ryan P.; Choi, Jin-Woo

2013-01-01

In an attempt to give a brief introduction to carbon nanotube inkjet printing, this review paper discusses the issues that come along with preparing and printing carbon nanotube ink. Carbon nanotube inkjet printing is relatively new, but it has great potential for broad applications in flexible and printable electronics, transparent electrodes, electronic sensors, and so on due to its low cost and the extraordinary properties of carbon nanotubes. In addition to the formulation of carbon nanotube ink and its printing technologies, recent progress and achievements of carbon nanotube inkjet printing are reviewed in detail with brief discussion on the future outlook of the technology. PMID:28348344

Organic materials for printed electronics

NASA Astrophysics Data System (ADS)

Berggren, M.; Nilsson, D.; Robinson, N. D.

2007-01-01

Organic materials can offer a low-cost alternative for printed electronics and flexible displays. However, research in these systems must exploit the differences - via molecular-level control of functionality - compared with inorganic electronics if they are to become commercially viable.

Thumbnail Sketches: The Chemistry of Printed Circuit Substrates: Some of the Latest Developments.

ERIC Educational Resources Information Center

Freeman, James H.

1984-01-01

Discusses some of the latest developments in the chemistry of printed circuit substrates. Topics considered include soldering, dicy (a catalyst), Kevlar (an aramid polymer fiber), maleimide copolymers, and flexible circuits. (JN)

Roll-to-Roll Gravure Printed Electrochemical Sensors for Wearable and Medical Devices.

PubMed

Bariya, Mallika; Shahpar, Ziba; Park, Hyejin; Sun, Junfeng; Jung, Younsu; Gao, Wei; Nyein, Hnin Yin Yin; Liaw, Tiffany Sun; Tai, Li-Chia; Ngo, Quynh P; Chao, Minghan; Zhao, Yingbo; Hettick, Mark; Cho, Gyoujin; Javey, Ali

2018-06-25

As recent developments in noninvasive biosensors spearhead the thrust toward personalized health and fitness monitoring, there is a need for high throughput, cost-effective fabrication of flexible sensing components. Toward this goal, we present roll-to-roll (R2R) gravure printed electrodes that are robust under a range of electrochemical sensing applications. We use inks and electrode morphologies designed for electrochemical and mechanical stability, achieving devices with uniform redox kinetics printed on 150 m flexible substrate rolls. We show that these electrodes can be functionalized into consistently high performing sensors for detecting ions, metabolites, heavy metals, and other small molecules in noninvasively accessed biofluids, including sensors for real-time, in situ perspiration monitoring during exercise. This development of robust and versatile R2R gravure printed electrodes represents a key translational step in enabling large-scale, low-cost fabrication of disposable wearable sensors for personalized health monitoring applications.

Printable elastic conductors with a high conductivity for electronic textile applications

PubMed Central

Matsuhisa, Naoji; Kaltenbrunner, Martin; Yokota, Tomoyuki; Jinno, Hiroaki; Kuribara, Kazunori; Sekitani, Tsuyoshi; Someya, Takao

2015-01-01

The development of advanced flexible large-area electronics such as flexible displays and sensors will thrive on engineered functional ink formulations for printed electronics where the spontaneous arrangement of molecules aids the printing processes. Here we report a printable elastic conductor with a high initial conductivity of 738 S cm−1 and a record high conductivity of 182 S cm−1 when stretched to 215% strain. The elastic conductor ink is comprised of Ag flakes, a fluorine rubber and a fluorine surfactant. The fluorine surfactant constitutes a key component which directs the formation of surface-localized conductive networks in the printed elastic conductor, leading to a high conductivity and stretchability. We demonstrate the feasibility of our inks by fabricating a stretchable organic transistor active matrix on a rubbery stretchability-gradient substrate with unimpaired functionality when stretched to 110%, and a wearable electromyogram sensor printed onto a textile garment. PMID:26109453

Method for Fabricating and Packaging an M.Times.N Phased-Array Antenna

NASA Technical Reports Server (NTRS)

Xu, Xiaochuan (Inventor); Chen, Yihong (Inventor); Chen, Ray T. (Inventor); Subbaraman, Harish (Inventor)

2017-01-01

A method for fabricating an M.times.N, P-bit phased-array antenna on a flexible substrate is disclosed. The method comprising ink jet printing and hardening alignment marks, antenna elements, transmission lines, switches, an RF coupler, and multilayer interconnections onto the flexible substrate. The substrate of the M.times.N, P-bit phased-array antenna may comprise an integrated control circuit of printed electronic components such as, photovoltaic cells, batteries, resistors, capacitors, etc. Other embodiments are described and claimed.

Rapid Formation and Flexible Expression of Memories of Subliminal Word Pairs

PubMed Central

Reber, Thomas P.; Henke, Katharina

2011-01-01

Our daily experiences are incidentally and rapidly encoded as episodic memories. Episodic memories consist of numerous associations (e.g., who gave what to whom where and when) that can be expressed flexibly in new situations. Key features of episodic memory are speed of encoding, its associative nature, and its representational flexibility. Another defining feature of human episodic memory has been consciousness of encoding/retrieval. Here, we show that humans can rapidly form associations between subliminal words and minutes later retrieve these associations even if retrieval words were conceptually related to, but different from encoding words. Because encoding words were presented subliminally, associative encoding, and retrieval were unconscious. Unconscious association formation and retrieval were dependent on a preceding understanding of task principles. We conclude that key computations underlying episodic memory – rapid encoding and flexible expression of associations – can operate outside consciousness. PMID:22125545

Fully printed flexible and disposable wireless cyclic voltammetry tag.

PubMed

Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

2015-01-29

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to -500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

Fully printed flexible and disposable wireless cyclic voltammetry tag

PubMed Central

Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

2015-01-01

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to −500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health. PMID:25630250

Fully printed flexible and disposable wireless cyclic voltammetry tag

NASA Astrophysics Data System (ADS)

Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

2015-01-01

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to -500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

A fully roll-to-roll gravure-printed carbon nanotube-based active matrix for multi-touch sensors

PubMed Central

Lee, Wookyu; Koo, Hyunmo; Sun, Junfeng; Noh, Jinsoo; Kwon, Kye-Si; Yeom, Chiseon; Choi, Younchang; Chen, Kevin; Javey, Ali; Cho, Gyoujin

2015-01-01

Roll-to-roll (R2R) printing has been pursued as a commercially viable high-throughput technology to manufacture flexible, disposable, and inexpensive printed electronic devices. However, in recent years, pessimism has prevailed because of the barriers faced when attempting to fabricate and integrate thin film transistors (TFTs) using an R2R printing method. In this paper, we report 20 × 20 active matrices (AMs) based on single-walled carbon nanotubes (SWCNTs) with a resolution of 9.3 points per inch (ppi) resolution, obtained using a fully R2R gravure printing process. By using SWCNTs as the semiconducting layer and poly(ethylene terephthalate) (PET) as the substrate, we have obtained a device yield above 98%, and extracted the key scalability factors required for a feasible R2R gravure manufacturing process. Multi-touch sensor arrays were achieved by laminating a pressure sensitive rubber onto the SWCNT-TFT AM. This R2R gravure printing system overcomes the barriers associated with the registration accuracy of printing each layer and the variation of the threshold voltage (Vth). By overcoming these barriers, the R2R gravure printing method can be viable as an advanced manufacturing technology, thus enabling the high-throughput production of flexible, disposable, and human-interactive cutting-edge electronic devices based on SWCNT-TFT AMs. PMID:26635237

A novel 3D bioprinted flexible and biocompatible hydrogel bioelectronic platform.

PubMed

Agarwala, Shweta; Lee, Jia Min; Ng, Wei Long; Layani, Michael; Yeong, Wai Yee; Magdassi, Shlomo

2018-04-15

Bioelectronics platforms are gaining widespread attention as they provide a template to study the interactions between biological species and electronics. Decoding the effect of the electrical signals on the cells and tissues holds the promise for treating the malignant tissue growth, regenerating organs and engineering new-age medical devices. This work is a step forward in this direction, where bio- and electronic materials co-exist on one platform without any need for post processing. We fabricate a freestanding and flexible hydrogel based platform using 3D bioprinting. The fabrication process is simple, easy and provides a flexible route to print materials with preferred shapes, size and spatial orientation. Through the design of interdigitated electrodes and heating coil, the platform can be tailored to print various circuits for different functionalities. The biocompatibility of the printed platform is tested using C2C12 murine myoblasts cell line. Furthermore, normal human dermal fibroblasts (primary cells) are also seeded on the platform to ascertain the compatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

QR encoded smart oral dosage forms by inkjet printing.

PubMed

Edinger, Magnus; Bar-Shalom, Daniel; Sandler, Niklas; Rantanen, Jukka; Genina, Natalja

2018-01-30

The use of inkjet printing (IJP) technology enables the flexible manufacturing of personalized medicine with the doses tailored for each patient. In this study we demonstrate, for the first time, the applicability of IJP in the production of edible dosage forms in the pattern of a quick response (QR) code. This printed pattern contains the drug itself and encoded information relevant to the patient and/or healthcare professionals. IJP of the active pharmaceutical ingredient (API)-containing ink in the pattern of QR code was performed onto a newly developed porous and flexible, but mechanically stable substrate with a good absorption capacity. The printing did not affect the mechanical properties of the substrate. The actual drug content of the printed dosage forms was in accordance with the encoded drug content. The QR encoded dosage forms had a good print definition without significant edge bleeding. They were readable by a smartphone even after storage in harsh conditions. This approach of efficient data incorporation and data storage combined with the use of smart devices can lead to safer and more patient-friendly drug products in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Guide wire extension for shape memory polymer occlusion removal devices

DOEpatents

Maitland, Duncan J [Pleasant Hill, CA; Small, IV, Ward; Hartman, Jonathan [Sacramento, CA

2009-11-03

A flexible extension for a shape memory polymer occlusion removal device. A shape memory polymer instrument is transported through a vessel via a catheter. A flexible elongated unit is operatively connected to the distal end of the shape memory polymer instrument to enhance maneuverability through tortuous paths en route to the occlusion.

Solution processed molecular floating gate for flexible flash memories

NASA Astrophysics Data System (ADS)

Zhou, Ye; Han, Su-Ting; Yan, Yan; Huang, Long-Biao; Zhou, Li; Huang, Jing; Roy, V. A. L.

2013-10-01

Solution processed fullerene (C60) molecular floating gate layer has been employed in low voltage nonvolatile memory device on flexible substrates. We systematically studied the charge trapping mechanism of the fullerene floating gate for both p-type pentacene and n-type copper hexadecafluorophthalocyanine (F16CuPc) semiconductor in a transistor based flash memory architecture. The devices based on pentacene as semiconductor exhibited both hole and electron trapping ability, whereas devices with F16CuPc trapped electrons alone due to abundant electron density. All the devices exhibited large memory window, long charge retention time, good endurance property and excellent flexibility. The obtained results have great potential for application in large area flexible electronic devices.

Solution processed molecular floating gate for flexible flash memories

PubMed Central

Zhou, Ye; Han, Su-Ting; Yan, Yan; Huang, Long-Biao; Zhou, Li; Huang, Jing; Roy, V. A. L.

2013-01-01

Solution processed fullerene (C60) molecular floating gate layer has been employed in low voltage nonvolatile memory device on flexible substrates. We systematically studied the charge trapping mechanism of the fullerene floating gate for both p-type pentacene and n-type copper hexadecafluorophthalocyanine (F16CuPc) semiconductor in a transistor based flash memory architecture. The devices based on pentacene as semiconductor exhibited both hole and electron trapping ability, whereas devices with F16CuPc trapped electrons alone due to abundant electron density. All the devices exhibited large memory window, long charge retention time, good endurance property and excellent flexibility. The obtained results have great potential for application in large area flexible electronic devices. PMID:24172758

The role of verbal labels on flexible memory retrieval at 12-months of age.

PubMed

Taylor, Gemma; Liu, Hao; Herbert, Jane S

2016-11-01

The provision of verbal labels enhances 12-month-old infants' memory flexibility across a form change in a puppet imitation task (Herbert, 2011), although the mechanisms for this effect remain unclear. Here we investigate whether verbal labels can scaffold flexible memory retrieval when task difficulty increases and consider the mechanism responsible for the effect of language cues on early memory flexibility. Twelve-month-old infants were provided with English, Chinese, or empty language cues during a difficult imitation task, a combined change in the puppet's colour and form at the test (Hayne et al., 1997). Imitation performance by infants in the English language condition only exceeded baseline performance after the 10-min delay. Thus, verbal labels facilitated flexible memory retrieval on this task. There were no correlations between infants' language comprehension and imitation performance. Thus, it is likely that verbal labels facilitate both attention and categorisation during encoding and retrieval. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

PERK Regulates Working Memory and Protein Synthesis-Dependent Memory Flexibility

PubMed Central

Zhu, Siying; Henninger, Keely; McGrath, Barbara C.; Cavener, Douglas R.

2016-01-01

PERK (EIF2AK3) is an ER-resident eIF2α kinase required for memory flexibility and metabotropic glutamate receptor-dependent long-term depression, processes known to be dependent on new protein synthesis. Here we investigated PERK’s role in working memory, a cognitive ability that is independent of new protein synthesis, but instead is dependent on cellular Ca2+ dynamics. We found that working memory is impaired in forebrain-specific Perk knockout and pharmacologically PERK-inhibited mice. Moreover, inhibition of PERK in wild-type mice mimics the fear extinction impairment observed in forebrain-specific Perk knockout mice. Our findings reveal a novel role of PERK in cognitive functions and suggest that PERK regulates both Ca2+ -dependent working memory and protein synthesis-dependent memory flexibility. PMID:27627766

Solvent-Free Toner Printing of Organic Semiconductor Layer in Flexible Thin-Film Transistors

NASA Astrophysics Data System (ADS)

Sakai, Masatoshi; Koh, Tokuyuki; Toyoshima, Kenji; Nakamori, Kouta; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Shinamura, Shoji; Kudo, Kazuhiro

2017-07-01

A solvent-free printing process for printed electronics is successfully developed using toner-type patterning of organic semiconductor toner particles and the subsequent thin-film formation. These processes use the same principle as that used for laser printing. The organic thin-film transistors are prepared by electrically distributing the charged toner onto a Au electrode on a substrate film, followed by thermal lamination. The thermal lamination is effective for obtaining an oriented and crystalline thin film. Toner printing is environmentally friendly compared with other printing technologies because it is solvent free, saves materials, and enables easy recycling. In addition, this technology simultaneously enables both wide-area and high-resolution printing.

Memory preservation made prestigious but easy

NASA Astrophysics Data System (ADS)

Fageth, Reiner; Debus, Christina; Sandhaus, Philipp

2011-01-01

Preserving memories combined with story-telling using either photo books for multiple images or high quality products such as one or a few images printed on canvas or images mounted on acryl to create high-quality wall decorations are gradually becoming more popular than classical 4*6 prints and classical silver halide posters. Digital printing via electro photography and ink jet is increasingly replacing classical silver halide technology as the dominant production technology for these kinds of products. Maintaining a consistent and comparable quality of output is becoming more challenging than using silver halide paper for both, prints and posters. This paper describes a unique approach of combining both desktop based software to initiate a compelling project and the use of online capabilities in order to finalize and optimize that project in an online environment in a community process. A comparison of the consumer behavior between online and desktop based solutions for generating photo books will be presented.

Working memory load affects repetitive behaviour but not cognitive flexibility in adolescent autism spectrum disorder.

PubMed

Wolff, Nicole; Chmielewski, Witold X; Beste, Christian; Roessner, Veit

2017-03-16

Autism spectrum disorder (ASD) is associated with repetitive and stereotyped behaviour, suggesting that cognitive flexibility may be deficient in ASD. A central, yet not examined aspect to understand possible deficits in flexible behaviour in ASD relates (i) to the role of working memory and (ii) to neurophysiological mechanisms underlying behavioural modulations. We analysed behavioural and neurophysiological (EEG) correlates of cognitive flexibility using a task-switching paradigm with and without working memory load in adolescents with ASD and typically developing controls (TD). Adolescents with ASD versus TD show similar performance in task switching with no memory load, indicating that 'pure' cognitive flexibility is not in deficit in adolescent ASD. However performance during task repetition decreases with increasing memory load. Neurophysiological data reflect the pattern of behavioural effects, showing modulations in P2 and P3 event-related potentials. Working memory demands affect repetitive behaviour while processes of cognitive flexibility are unaffected. Effects emerge due to deficits in preparatory attentional processes and deficits in task rule activation, organisation and implementation of task sets when repetitive behaviour is concerned. It may be speculated that the habitual response mode in ASD (i.e. repetitive behaviour) is particularly vulnerable to additional demands on executive control processes.

Bioinspired Multifunctional Superhydrophobic Surfaces with Carbon-Nanotube-Based Conducting Pastes by Facile and Scalable Printing.

PubMed

Han, Joong Tark; Kim, Byung Kuk; Woo, Jong Seok; Jang, Jeong In; Cho, Joon Young; Jeong, Hee Jin; Jeong, Seung Yol; Seo, Seon Hee; Lee, Geon-Woong

2017-03-01

Directly printed superhydrophobic surfaces containing conducting nanomaterials can be used for a wide range of applications in terms of nonwetting, anisotropic wetting, and electrical conductivity. Here, we demonstrated that direct-printable and flexible superhydrophobic surfaces were fabricated on flexible substrates via with an ultrafacile and scalable screen printing with carbon nanotube (CNT)-based conducting pastes. A polydimethylsiloxane (PDMS)-polyethylene glycol (PEG) copolymer was used as an additive for conducting pastes to realize the printability of the conducting paste as well as the hydrophobicity of the printed surface. The screen-printed conducting surfaces showed a high water contact angle (WCA) (>150°) and low contact angle hysteresis (WCA < 5°) at 25 wt % PDMS-PEG copolymer in the paste, and they have an electrical conductivity of over 1000 S m -1 . Patterned superhydrophobic surfaces also showed sticky superhydrophobic characteristics and were used to transport water droplets. Moreover, fabricated films on metal meshes were used for an oil/water separation filter, and liquid evaporation behavior was investigated on the superhydrophobic and conductive thin-film heaters by applying direct current voltage to the film.

Plasma Jet Printing and in Situ Reduction of Highly Acidic Graphene Oxide.

PubMed

Dey, Avishek; Krishnamurthy, Satheesh; Bowen, James; Nordlund, Dennis; Meyyappan, M; Gandhiraman, Ram P

2018-05-23

Miniaturization of electronic devices and the advancement of Internet of Things pose exciting challenges to develop technologies for patterned deposition of functional nanomaterials. Printed and flexible electronic devices and energy storage devices can be embedded onto clothing or other flexible surfaces. Graphene oxide (GO) has gained much attention in printed electronics due its solution processability, robustness, and high electrical conductivity in the reduced state. Here, we introduce an approach to print GO films from highly acidic suspensions with in situ reduction using an atmospheric pressure plasma jet. Low-temperature plasma of a He and H 2 mixture was used successfully to reduce a highly acidic GO suspension (pH < 2) in situ during deposition. This technique overcomes the multiple intermediate steps required to increase the conductivity of deposited GO. X-ray spectroscopic studies confirmed that the reaction intermediates and the concentration of oxygen functionalities bonded to GO have been reduced significantly by this approach without any additional steps. Moreover, the reduced GO films showed enhanced conductivity. Hence, this technique has a strong potential for printing conducting patterns of GO for a range of large-scale applications.

Fully-printed high-performance organic thin-film transistors and circuitry on one-micron-thick polymer films

NASA Astrophysics Data System (ADS)

Fukuda, Kenjiro; Takeda, Yasunori; Yoshimura, Yudai; Shiwaku, Rei; Tran, Lam Truc; Sekine, Tomohito; Mizukami, Makoto; Kumaki, Daisuke; Tokito, Shizuo

2014-06-01

Thin, ultra-flexible devices that can be manufactured in a process that covers a large area will be essential to realizing low-cost, wearable electronic applications including foldable displays and medical sensors. The printing technology will be instrumental in fabricating these novel electronic devices and circuits; however, attaining fully printed devices on ultra-flexible films in large areas has typically been a challenge. Here we report on fully printed organic thin-film transistor devices and circuits fabricated on 1-μm-thick parylene-C films with high field-effect mobility (1.0 cm2 V-1 s-1) and fast operating speeds (about 1 ms) at low operating voltages. The devices were extremely light (2 g m-2) and exhibited excellent mechanical stability. The devices remained operational even under 50% compressive strain without significant changes in their performance. These results represent significant progress in the fabrication of fully printed organic thin-film transistor devices and circuits for use in unobtrusive electronic applications such as wearable sensors.

Low-Cost Fabrication of Printed Electronics Devices through Continuous Wave Laser-Induced Forward Transfer.

PubMed

Sopeña, Pol; Arrese, Javier; González-Torres, Sergio; Fernández-Pradas, Juan Marcos; Cirera, Albert; Serra, Pere

2017-09-06

Laser-induced forward transfer (LIFT) is a direct-writing technique that allows printing inks from a liquid film in a similar way to inkjet printing but with fewer limitations concerning ink viscosity and loading particle size. In this work, we prove that liquid inks can be printed through LIFT by using continuous wave (CW) instead of pulsed lasers, which allows a substantial reduction in the cost of the printing system. Through the fabrication of a functional circuit on both rigid and flexible substrates (plastic and paper), we provide a proof-of-concept that demonstrates the versatility of the technique for printed electronics applications.

A flexible nonvolatile resistive switching memory device based on ZnO film fabricated on a foldable PET substrate.

PubMed

Sun, Bai; Zhang, Xuejiao; Zhou, Guangdong; Yu, Tian; Mao, Shuangsuo; Zhu, Shouhui; Zhao, Yong; Xia, Yudong

2018-06-15

In this work, a flexible resistive switching memory device based on ZnO film was fabricated using a foldable Polyethylene terephthalate (PET) film as substrate while Ag and Ti acts top and bottom electrode. Our as-prepared device represents an outstanding nonvolatile memory behavior with good "write-read-erase-read" stability at room temperature. Finally, a physical model of Ag conductive filament is constructed to understanding the observed memory characteristics. The work provides a new way for the preparation of flexible memory devices based on ZnO films, and especially provides an experimental basis for the exploration of high-performance and portable nonvolatile resistance random memory (RRAM). Copyright © 2018 Elsevier Inc. All rights reserved.

All-inkjet-printed flexible ZnO micro photodetector for a wearable UV monitoring device.

PubMed

Tran, Van-Thai; Wei, Yuefan; Yang, Hongyi; Zhan, Zhaoyao; Du, Hejun

2017-03-03

Fabrication of small-sized patterns of inorganic semiconductor onto flexible substrates is a major concern when manufacturing wearable devices for measuring either biometric or environmental parameters. In this study, micro-sized flexible ZnO UV photodetectors have been thoroughly prepared by a facile inkjet printing technology and followed with heat treatments. A simple ink recipe of zinc acetate precursor solution was investigated. It is found that the substrate temperature during zinc precursor ink depositing has significant effects on ZnO pattern shape, film morphology, and crystallization. The device fabricated from the additive manufacturing approach has good bendability, Ohmic contact, short response time as low as 0.3 s, and high on/off ratio of 3525. We observed the sensor's dependence of response/decay time by the illuminating UV light intensity. The whole process is based on additive manufacturing which has many benefits such as rapid prototyping, saving material, being environmentally friendly, and being capable of creating high-resolution patterns. In addition, this method can be applied to flexible substrates, which makes the device more applicable for applications requiring flexibility such as wearable devices. The proposed all-inkjet-printing approach for a micro-sized ZnO UV photodetector would significantly simplify the fabrication process of micro-sized inorganic semiconductor-based devices. A potential application is real-time monitoring of UV light exposure to warn users about unsafe direct sunlight to implement suitable avoidance solutions.

Common Problems and Solutions for Being Physically Active

MedlinePlus

... such as walking, dancing and tennis. Do your stretching, balance and flexibility activities while you watch TV. ... a nearby health club. Print and take the Stretching and Flexibility and Strengthening sheets with you. All ...

Natural printed silk substrate circuit fabricated via surface modification using one step thermal transfer and reduction graphene oxide

NASA Astrophysics Data System (ADS)

Cao, Jiliang; Huang, Zhan; Wang, Chaoxia

2018-05-01

Graphene conductive silk substrate is a preferred material because of its biocompatibility, flexibility and comfort. A flexible natural printed silk substrate circuit was fabricated by one step transfer of graphene oxide (GO) paste from transfer paper to the surface of silk fabric and reduction of the GO to reduced graphene oxide (RGO) using a simple hot press treatment. The GO paste was obtained through ultrasonic stirring exfoliation under low temperature, and presented excellent printing rheological properties at high concentration. The silk fabric was obtained a surface electric resistance as low as 12.15 KΩ cm-1, in the concentration of GO 50 g L-1 and hot press at 220 °C for 120 s. Though the whiteness and strength decreased with the increasing of hot press temperature and time slowly, the electric conductivity of RGO surface modification silk substrate improved obviously. The surface electric resistance of RGO/silk fabrics increased from 12.15 KΩ cm-1 to 18.05 KΩ cm-1, 28.54 KΩ cm-1 and 32.53 KΩ cm-1 after 10, 20 and 30 washing cycles, respectively. The results showed that the printed silk substrate circuit has excellent washability. This process requires no chemical reductant, and the reduction efficiency and reduction degree of GO is high. This time-effective and environmentally-friendly one step thermal transfer and reduction graphene oxide onto natural silk substrate method can be easily used to production of reduced graphene oxide (RGO) based flexible printed circuit.

Roll-to-roll Slot-die Printed Polymer Solar Cell by Self-Assembly.

PubMed

Yang, Junyu; Lin, Yuanbao; Zheng, Wenhao; Liu, Alei; Cai, Wanzhu; Yu, Xiaomin; Zhang, Fengling; Liang, Quanbin; Wu, Hongbin; Qin, Donghuan; Hou, Lintao

2018-06-12

Extremely simplified one-step roll-to-roll slot-die printed flexible ITO-free polymer solar cells (PSCs) are demonstrated based on ternary blends of electron-donor polymer thieno [3,4-b]thiophene/benzodithiophene (PTB7), electron-acceptor fullerene [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) and electron extracting polymer poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) at room temperature (RT) in ambient air. The flexible ITO-free PSC exhibits a comparable power conversion efficiency (PCE) with the device employing complicated two-step slot-die printing (5.29% vs 5.41%), which indicates that PFN molecules can migrate from the ternary nanocomposite towards Ag cathode via vertical self-assembly during the one-step slot-die printing process in air. To confirm the migration of PFN, the morphology and elemental analysis as well as charge transport of different active layers are investigated with in-situ transient film drying process, transmission electron microscopy, atomic force microscopy, contact angle and surface energy, X-ray photoelectron spectroscopy, scanning electron microscope, impedance spectroscopy, transient photovoltage and transient photocurrent as well as laser beam induced current. Moreover, the good air and mechanical stability of the flexible device with a decent PCE achieved in 1 cm2 PSCs at RT in air suggests the feasibility of energy-saving and time-saving one-step slot-die printing to large-scale roll-to-roll manufacture in the future.

Printing--Graphic Arts--Graphic Communications

ERIC Educational Resources Information Center

Hauenstein, A. Dean

1975-01-01

Recently, "graphic arts" has shifted from printing skills to a conceptual approach of production processes. "Graphic communications" must embrace the total system of communication through graphic media, to serve broad career education purposes; students taught concepts and principles can be flexible and adaptive. The author…

Nanoscale platinum printing on insulating substrates.

PubMed

O'Connell, C D; Higgins, M J; Sullivan, R P; Jamali, S S; Moulton, S E; Wallace, G G

2013-12-20

The deposition of noble metals on soft and/or flexible substrates is vital for several emerging applications including flexible electronics and the fabrication of soft bionic implants. In this paper, we describe a new strategy for the deposition of platinum electrodes on a range of materials, including insulators and flexible polymers. The strategy is enabled by two principle advances: (1) the introduction of a novel, low temperature strategy for reducing chloroplatinic acid to platinum using nitrogen plasma; (2) the development of a chloroplatinic acid based liquid ink formulation, utilizing ethylene glycol as both ink carrier and reducing agent, for versatile printing at nanoscale resolution using dip-pen nanolithography (DPN). The ink formulation has been printed and reduced upon Si, glass, ITO, Ge, PDMS, and Parylene C. The plasma treatment effects reduction of the precursor patterns in situ without subjecting the substrate to destructively high temperatures. Feature size is controlled via dwell time and degree of ink loading, and platinum features with 60 nm dimensions could be routinely achieved on Si. Reduction of the ink to platinum was confirmed by energy dispersive x-ray spectroscopy (EDS) elemental analysis and x-ray diffraction (XRD) measurements. Feature morphology was characterized by optical microscopy, SEM and AFM. The high electrochemical activity of individually printed Pt features was characterized using scanning electrochemical microscopy (SECM).

3D Printing the Complete CubeSat

NASA Technical Reports Server (NTRS)

Kief, Craig

2015-01-01

The 3D Printing the Complete CubeSat project is designed to advance the state-of-the-art in 3D printing for CubeSat applications. Printing in 3D has the potential to increase reliability, reduce design iteration time and provide greater design flexibility in the areas of radiation mitigation, communications, propulsion, and wiring, among others. This project is investigating the possibility of including propulsion systems into the design of printed CubeSat components. One such concept, an embedded micro pulsed plasma thruster (mPPT), could provide auxiliary reaction control propulsion for a spacecraft as a means to desaturate momentum wheels.

Printing versus coating - What will be the future production technology for printed electronics?

NASA Astrophysics Data System (ADS)

Glawe, Andrea; Eggerath, Daniel; Schäfer, Frank

2015-02-01

The market of Large Area Organic Printed Electronics is developing rapidly to increase efficiency and quality as well as to lower costs further. Applications for OPV, OLED, RFID and compact Printed Electronic systems are increasing. In order to make the final products more affordable, but at the same time highly accurate, Roll to Roll (R2R) production on flexible transparent polymer substrates is the way forward. There are numerous printing and coating technologies suitable depending on the design, the product application and the chemical process technology. Mainly the product design (size, pattern, repeatability) defines the application technology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, T.; Hu, M.; Guo, Q.

Here we report a study of printing of electronics using an office use laser printer. The proposed method eliminates those critical disadvantages of solvent-based printing techniques by taking the advantages of electroless deposition and laser printing. The synthesized toner acts as a catalyst for the electroless copper deposition as well as an adhesion-promoting buffer layer between the substrate and deposited copper. The easy metallization of printed patterns and strong metal-substrate adhesion make it an especially effective method for massive production of flexible printed circuits. The proposed process is a high throughput, low cost, efficient, and environmentally benign method for flexiblemore » electronics manufacturing.« less

Memory Flexibility training (MemFlex) to reduce depressive symptomatology in individuals with major depressive disorder: study protocol for a randomised controlled trial.

PubMed

Hitchcock, Caitlin; Hammond, Emily; Rees, Catrin; Panesar, Inderpal; Watson, Peter; Werner-Seidler, Aliza; Dalgleish, Tim

2015-11-03

Major depressive disorder (MDD) is associated with chronic biases in the allocation of attention and recollection of personal memories. Impaired flexibility in attention and autobiographical memory retrieval is seen to both maintain current symptoms and predict future depression. Development of innovative interventions to reduce maladaptive cognitive patterns and improve cognitive flexibility in the domain of memory may therefore advance current treatment approaches for depression. Memory specificity training and cognitive bias modification techniques have both shown some promise in improving cognitive flexibility. Here we outline plans for a trial of an innovative memory flexibility training programme, MemFlex, which advances current training techniques with the aim of improving flexibility of autobiographical memory retrieval. This trial seeks to estimate the efficacy of MemFlex, provide data on feasibility, and begin to explore mechanisms of change. We plan a single-blind, randomised, controlled, patient-level trial in which 50 individuals with MDD will complete either psychoeducation (n = 25) or MemFlex (n = 25). After completing pre-treatment measures and an orientation session, participants complete eight workbook-based sessions at home. Participants will then be assessed at post-treatment and at 3 month follow-up. The co-primary outcomes are depressive symptoms and diagnostic status at 3 month follow-up. The secondary outcomes are memory flexibility at post-treatment and number of depression free days at 3 month follow-up. Other process outcomes and mediators of any treatment effects will also be explored. This trial will establish the efficacy of MemFlex in improving memory flexibility, and reducing depressive symptoms. Any effects on process measures related to relapse may also indicate whether MemFlex may be helpful in reducing vulnerability to future depressive episodes. The low-intensity and workbook-based format of the programme may improve access to psychological therapies, and, if encouraging, the results of this study will provide a platform for later-phase trials. NCT02371291 (ClinicalTrials.gov), registered 9 February 2015.

Fully Printed Memristors from Cu-SiO2 Core-Shell Nanowire Composites

NASA Astrophysics Data System (ADS)

Catenacci, Matthew J.; Flowers, Patrick F.; Cao, Changyong; Andrews, Joseph B.; Franklin, Aaron D.; Wiley, Benjamin J.

2017-07-01

This article describes a fully printed memory in which a composite of Cu-SiO2 nanowires dispersed in ethylcellulose acts as a resistive switch between printed Cu and Au electrodes. A 16-cell crossbar array of these memristors was printed with an aerosol jet. The memristors exhibited moderate operating voltages (˜3 V), no degradation over 104 switching cycles, write speeds of 3 μs, and extrapolated retention times of 10 years. The low operating voltage enabled the programming of a fully printed 4-bit memristor array with an Arduino. The excellent performance of these fully printed memristors could help enable the creation of fully printed RFID tags and sensors with integrated data storage.

Flexible Retrieval: When True Inferences Produce False Memories

ERIC Educational Resources Information Center

Carpenter, Alexis C.; Schacter, Daniel L.

2017-01-01

Episodic memory involves flexible retrieval processes that allow us to link together distinct episodes, make novel inferences across overlapping events, and recombine elements of past experiences when imagining future events. However, the same flexible retrieval and recombination processes that underpin these adaptive functions may also leave…

Electrical conductivity and piezoresistive response of 3D printed thermoplastic polyurethane/multiwalled carbon nanotube composites

NASA Astrophysics Data System (ADS)

Hohimer, Cameron J.; Petrossian, Gayaneh; Ameli, Amir; Mo, Changki; Pötschke, Petra

2018-03-01

Additive manufacturing (AM) is an emerging field experiencing rapid growth. This paper presents a feasibility study of using fused-deposition modeling (FDM) techniques with smart materials to fabricate objects with sensing and actuating capabilities. The fabrication of objects with sensing typically requires the integration and assembly of multiple components. Incorporating sensing elements into a single FDM process has the potential to significantly simplify manufacturing. The integration of multiple materials, especially smart materials and those with multi-functional properties, into the FDM process is challenging and still requires further development. Previous works by the authors have demonstrated a good printability of thermoplastic polyurethane/multiwall carbon nanotubes (TPU/MWCNT) while maintaining conductivity and piezoresistive response. This research explores the effects of layer height, nozzle temperature, and bed temperature on the electrical conductivity and piezoresistive response of printed TPU/MWCNT nanocomposites. An impedance analyzer was used to determine the conductivity of printed samples under different printing conditions from 5Hz-13MHz. The samples were then tested under compression loads to measure the piezoresistive response. Results show the conductivity and piezoresistive response are only slightly affected by the print parameters and they can be largely considered independent of the print conditions within the examined ranges of print parameters. This behavior simplifies the printing process design for TPU/MWCNT complex structures. This work demonstrates the possibility of manufacturing embedded and multidirectional flexible strain sensors using an inexpensive and versatile method, with potential applications in soft robotics, flexible electronics, and health monitoring.

Scalability of carbon-nanotube-based thin film transistors for flexible electronic devices manufactured using an all roll-to-roll gravure printing system

PubMed Central

Koo, Hyunmo; Lee, Wookyu; Choi, Younchang; Sun, Junfeng; Bak, Jina; Noh, Jinsoo; Subramanian, Vivek; Azuma, Yasuo; Majima, Yutaka; Cho, Gyoujin

2015-01-01

To demonstrate that roll-to-roll (R2R) gravure printing is a suitable advanced manufacturing method for flexible thin film transistor (TFT)-based electronic circuits, three different nanomaterial-based inks (silver nanoparticles, BaTiO3 nanoparticles and single-walled carbon nanotubes (SWNTs)) were selected and optimized to enable the realization of fully printed SWNT-based TFTs (SWNT-TFTs) on 150-m-long rolls of 0.25-m-wide poly(ethylene terephthalate) (PET). SWNT-TFTs with 5 different channel lengths, namely, 30, 80, 130, 180, and 230 μm, were fabricated using a printing speed of 8 m/min. These SWNT-TFTs were characterized, and the obtained electrical parameters were related to major mechanical factors such as web tension, registration accuracy, impression roll pressure and printing speed to determine whether these mechanical factors were the sources of the observed device-to-device variations. By utilizing the electrical parameters from the SWNT-TFTs, a Monte Carlo simulation for a 1-bit adder circuit, as a reference, was conducted to demonstrate that functional circuits with reasonable complexity can indeed be manufactured using R2R gravure printing. The simulation results suggest that circuits with complexity, similar to the full adder circuit, can be printed with a 76% circuit yield if threshold voltage (Vth) variations of less than 30% can be maintained. PMID:26411839

Review of Recent Inkjet-Printed Capacitive Tactile Sensors

PubMed Central

Salim, Ahmed

2017-01-01

Inkjet printing is an advanced printing technology that has been used to develop conducting layers, interconnects and other features on a variety of substrates. It is an additive manufacturing process that offers cost-effective, lightweight designs and simplifies the fabrication process with little effort. There is hardly sufficient research on tactile sensors and inkjet printing. Advancements in materials science and inkjet printing greatly facilitate the realization of sophisticated tactile sensors. Starting from the concept of capacitive sensing, a brief comparison of printing techniques, the essential requirements of inkjet-printing and the attractive features of state-of-the art inkjet-printed tactile sensors developed on diverse substrates (paper, polymer, glass and textile) are presented in this comprehensive review. Recent trends in inkjet-printed wearable/flexible and foldable tactile sensors are evaluated, paving the way for future research. PMID:29125584

Pigment-cellulose nanofibril composite and its application as a separator-substrate in printed supercapacitors

NASA Astrophysics Data System (ADS)

Torvinen, Katariina; Lehtimäki, Suvi; Keränen, Janne T.; Sievänen, Jenni; Vartiainen, Jari; Hellén, Erkki; Lupo, Donald; Tuukkanen, Sampo

2015-11-01

Pigment-cellulose nanofibril (PCN) composites were manufactured in a pilot line and used as a separator-substrate in printed graphene and carbon nanotube supercapacitors. The composites consisted typically of 80% pigment and 20% cellulose nanofibrils (CNF). This composition makes them a cost-effective alternative as a substrate for printed electronics at high temperatures that only very special plastic films can nowadays stand. The properties of these substrates can be varied within a relatively large range by the selection of raw materials and their relative proportions. A semi-industrial scale pilot line was successfully used to produce smooth, flexible, and nanoporous composites, and their performance was tested in a double functional separator-substrate element in supercapacitors. The nanostructural carbon films printed on the composite worked simultaneously as high surface area active electrodes and current collectors. Low-cost supercapacitors made from environmentally friendly materials have significant potential for use in flexible, wearable, and disposable low-end products. [Figure not available: see fulltext.

Printing Smart Designs of Light Emitting Devices with Maintained Textile Properties.

PubMed

Verboven, Inge; Stryckers, Jeroen; Mecnika, Viktorija; Vandevenne, Glen; Jose, Manoj; Deferme, Wim

2018-02-13

To maintain typical textile properties, smart designs of light emitting devices are printed directly onto textile substrates. A first approach shows improved designs for alternating current powder electroluminescence (ACPEL) devices. A configuration with the following build-up, starting from the textile substrate, was applied using the screen printing technique: silver (10 µm)/barium titanate (10 µm)/zinc-oxide (10 µm) and poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (10 µm). Textile properties such as flexibility, drapability and air permeability are preserved by implementing a pixel-like design of the printed layers. Another route is the application of organic light emitting devices (OLEDs) fabricated out of following layers, also starting from the textile substrate: polyurethane or acrylate (10-20 µm) as smoothing layer/silver (200 nm)/poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (35 nm)/super yellow (80 nm)/calcium/aluminum (12/17 nm). Their very thin nm-range layer thickness, preserving the flexibility and drapability of the substrate, and their low working voltage, makes these devices the possible future in light-emitting wearables.

A study of selenium nanoparticles as charge storage element for flexible semi-transparent memory devices

NASA Astrophysics Data System (ADS)

Alotaibi, Sattam; Nama Manjunatha, Krishna; Paul, Shashi

2017-12-01

Flexible Semi-Transparent electronic memory would be useful in coming years for integrated flexible transparent electronic devices. However, attaining such flexibility and semi-transparency leads to the boundaries in material composition. Thus, impeding processing speed and device performance. In this work, we present the use of inorganic stable selenium nanoparticles (Se-NPs) as a storage element and hydrogenated amorphous carbon (a-C:H) as an insulating layer in two terminal non-volatile physically flexible and semi-transparent capacitive memory devices (2T-NMDs). Furthermore, a-C:H films can be deposited at very low temperature (<40° C) on a variety of substrates (including many kinds of plastic substrates) by an industrial technique called Plasma Enhanced Chemical Vapour Deposition (PECVD) which is available in many existing fabrication labs. Self-assembled Se-NPs has several unique features including deposition at room temperature by simple vacuum thermal evaporation process without the need for further optimisation. This facilitates the fabrication of memory on a flexible substrate. Moreover, the memory behaviour of the Se-NPs was found to be more distinct than those of the semiconductor and metal nanostructures due to higher work function compared to the commonly used semiconductor and metal species. The memory behaviour was observed from the hysteresis of current-voltage (I-V) measurements while the two distinguishable electrical conductivity states (;0; and "1") were studied by current-time (I-t) measurements.

A High-yield Two-step Transfer Printing Method for Large-scale Fabrication of Organic Single-crystal Devices on Arbitrary Substrates

PubMed Central

Deng, Wei; Zhang, Xiujuan; Pan, Huanhuan; Shang, Qixun; Wang, Jincheng; Zhang, Xiaohong; Zhang, Xiwei; Jie, Jiansheng

2014-01-01

Single-crystal organic nanostructures show promising applications in flexible and stretchable electronics, while their applications are impeded by the large incompatibility with the well-developed photolithography techniques. Here we report a novel two-step transfer printing (TTP) method for the construction of organic nanowires (NWs) based devices onto arbitrary substrates. Copper phthalocyanine (CuPc) NWs are first transfer-printed from the growth substrate to the desired receiver substrate by contact-printing (CP) method, and then electrode arrays are transfer-printed onto the resulting receiver substrate by etching-assisted transfer printing (ETP) method. By utilizing a thin copper (Cu) layer as sacrificial layer, microelectrodes fabricated on it via photolithography could be readily transferred to diverse conventional or non-conventional substrates that are not easily accessible before with a high transfer yield of near 100%. The ETP method also exhibits an extremely high flexibility; various electrodes such as Au, Ti, and Al etc. can be transferred, and almost all types of organic devices, such as resistors, Schottky diodes, and field-effect transistors (FETs), can be constructed on planar or complex curvilinear substrates. Significantly, these devices can function properly and exhibit closed or even superior performance than the device counterparts fabricated by conventional approach. PMID:24942458

Flexible memory retrieval in bilingual 6-month-old infants.

PubMed

Brito, Natalie; Barr, Rachel

2014-07-01

Memory flexibility is a hallmark of the human memory system. As indexed by generalization between perceptually dissimilar objects, memory flexibility develops gradually during infancy. A recent study has found a bilingual advantage in memory generalization at 18 months of age [Brito and Barr [2012] Developmental Science, 15, 812-816], and the present study examines when this advantage may first emerge. In the current study, bilingual 6-month-olds were more likely than monolinguals to generalize to a puppet that differed in two features (shape and color) than monolingual 6-month-olds. When challenged with a less complex change, two puppets that differed only in one feature--color, monolingual 6-month-olds were also able to generalize. These findings demonstrate early emerging differences in memory generalization in bilingual infants, and have important implications for our understanding of how early environmental variations shape the trajectory of memory development. © 2013 Wiley Periodicals, Inc.

Influence of Layer Thickness, Raster Angle, Deformation Temperature and Recovery Temperature on the Shape-Memory Effect of 3D-Printed Polylactic Acid Samples

PubMed Central

Wu, Wenzheng; Ye, Wenli; Wu, Zichao; Geng, Peng; Wang, Yulei; Zhao, Ji

2017-01-01

The success of the 3D-printing process depends upon the proper selection of process parameters. However, the majority of current related studies focus on the influence of process parameters on the mechanical properties of the parts. The influence of process parameters on the shape-memory effect has been little studied. This study used the orthogonal experimental design method to evaluate the influence of the layer thickness H, raster angle θ, deformation temperature Td and recovery temperature Tr on the shape-recovery ratio Rr and maximum shape-recovery rate Vm of 3D-printed polylactic acid (PLA). The order and contribution of every experimental factor on the target index were determined by range analysis and ANOVA, respectively. The experimental results indicated that the recovery temperature exerted the greatest effect with a variance ratio of 416.10, whereas the layer thickness exerted the smallest effect on the shape-recovery ratio with a variance ratio of 4.902. The recovery temperature exerted the most significant effect on the maximum shape-recovery rate with the highest variance ratio of 1049.50, whereas the raster angle exerted the minimum effect with a variance ratio of 27.163. The results showed that the shape-memory effect of 3D-printed PLA parts depended strongly on recovery temperature, and depended more weakly on the deformation temperature and 3D-printing parameters. PMID:28825617

22. Photocopy of photograph (original print in files of Theatre ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. Photocopy of photograph (original print in files of Theatre Historical Society, P.O. Box 101, Notre Dame, IN 46556) Photographer unknown 1938 TREMONT STREET ANNEX, LOOKING SOUTHEAST - B. F. Keith Memorial Theatre, 539 Washington Street, Boston, Suffolk County, MA

Flexible Nonstick Replica Mold for Transfer Printing of Ag Ink.

PubMed

Lee, Bong Kuk; Yu, Han Young; Kim, Yarkyeon; Yoon, Yong Sun; Jang, Won Ik; Do, Lee-Mi; Park, Ji-Ho; Park, Jaehoon

2016-03-01

We report the fabrication of flexible replica molds for transfer printing of Ag ink on a rigid glass substrate. As mold precursors, acrylic mixtures were prepared from silsesquioxane-based materials, silicone acrylate, poly(propylene glycol) diacrylate, 3,3,4,4,5,5,6,6,7,7,8,8, 9,9,10,10,10-heptadecafluorodecyl methacrylate, and photoinitiator. By using these materials, the replica molds were fabricated from a silicon master onto a flexible substrate by means of UV-assisted molding process at room temperature. The wettability of Ag ink decreased with increase in the water contact angle of replica molds. On the other hand, the transfer rate of Ag ink onto adhesive-modified substrates increased with increase in the water contact angle of replica molds. Transferred patterns were found to be thermally stable on the photocurable adhesive layer, whereas Ag-ink patterns transferred on non-photocurable adhesives were distorted by thermal treatment. We believe that these characteristics of replica molds and adhesives offer a new strategy for the development of the transfer printing of solution-based ink materials.

Printing and Folding: A Solution for High-Throughput Processing of Organic Thin-Film Thermoelectric Devices

PubMed Central

Mortazavinatanzi, Seyedmohammad; Rosendahl, Lasse

2018-01-01

Wearable electronics are rapidly expanding, especially in applications like health monitoring through medical sensors and body area networks (BANs). Thermoelectric generators (TEGs) have been the main candidate among the different types of energy harvesting methods for body-mounted or even implantable sensors. Introducing new semiconductor materials like organic thermoelectric materials and advancing manufacturing techniques are paving the way to overcome the barriers associated with the bulky and inflexible nature of the common TEGs and are making it possible to fabricate flexible and biocompatible modules. Yet, the lower efficiency of these materials in comparison with bulk-inorganic counterparts as well as applying them mostly in the form of thin layers on flexible substrates limits their applications. This research aims to improve the functionality of thin and flexible organic thermoelectric generators (OTEs) by utilizing a novel design concept inspired by origami. The effects of critical geometric parameters are investigated using COMSOL Multiphysics to further prove the concept of printing and folding as an approach for the system level optimization of printed thin film TEGs. PMID:29584634

Acoustic Neuroma: Questions to Discuss with Your Doctor

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Colonic Polyps: Questions to Discuss with Your Doctor

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When You Visit Your Doctor After a Heart Attack

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When You Visit Your Doctor: Irregular Menstrual Periods

MedlinePlus

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Increasing dimension of structures by 4D printing shape memory polymers via fused deposition modeling

NASA Astrophysics Data System (ADS)

Hu, G. F.; Damanpack, A. R.; Bodaghi, M.; Liao, W. H.

2017-12-01

The main objective of this paper is to introduce a 4D printing method to program shape memory polymers (SMPs) during fabrication process. Fused deposition modeling (FDM) as a filament-based printing method is employed to program SMPs during depositing the material. This method is implemented to fabricate complicated polymeric structures by self-bending features without need of any post-programming. Experiments are conducted to demonstrate feasibility of one-dimensional (1D)-to 2D and 2D-to-3D self-bending. It is shown that 3D printed plate structures can transform into masonry-inspired 3D curved shell structures by simply heating. Good reliability of SMP programming during printing process is also demonstrated. A 3D macroscopic constitutive model is established to simulate thermo-mechanical features of the printed SMPs. Governing equations are also derived to simulate programming mechanism during printing process and shape change of self-bending structures. In this respect, a finite element formulation is developed considering von-Kármán geometric nonlinearity and solved by implementing iterative Newton-Raphson scheme. The accuracy of the computational approach is checked with experimental results. It is demonstrated that the theoretical model is able to replicate the main characteristics observed in the experiments. This research is likely to advance the state of the art FDM 4D printing, and provide pertinent results and computational tool that are instrumental in design of smart materials and structures with self-bending features.

Principle of topography-directed inkjet printing for functional micro-tracks in flexible substrates

NASA Astrophysics Data System (ADS)

Keum, Chang-Min; Lee, In-Ho; Park, Hea-Lim; Kim, Chiwoo; Lüssem, Björn; Choi, Jong Sun; Lee, Sin-Doo

2017-06-01

We present a general principle of topography-directed (TD) inkjet printing for functional micro-tracks embedded in a flexible elastomer substrate. The essential features of the TD inkjet printing in a micro-structured substrate with periodic grooves and ridges are described in terms of the topographic parameters for the transformation from a single droplet to a filament or an edge-disjoint pattern of ink in the groove. Silver ink, being widely used for producing conductive wires by conventional inkjet printing, is utilized as a testbed in our study. The underlying mechanisms for the spreading and drying processes of ink drops under the topographic compartment can be understood in a two-dimensional parameter space of the aspect ratio of the groove and the contact angle of ink on the substrate. The wetting morphologies of ink droplets are described in an analytical model where the Laplace pressure and the mean curvature at the vapor/ink interface are taken into account. The first principle of the TD inkjet printing would be applicable for constructing a variety of functional micro-tracks with high pattern fidelity from different classes of solutions such as conducting polymers, organic semiconductors, and colloidal nanoparticles.

Open-source three-dimensional printing of biodegradable polymer scaffolds for tissue engineering.

PubMed

Trachtenberg, Jordan E; Mountziaris, Paschalia M; Miller, Jordan S; Wettergreen, Matthew; Kasper, Fred K; Mikos, Antonios G

2014-12-01

The fabrication of scaffolds for tissue engineering requires elements of customization depending on the application and is often limited due to the flexibility of the processing technique. This investigation seeks to address this obstacle by utilizing an open-source three-dimensional printing (3DP) system that allows vast customizability and facilitates reproduction of experiments. The effects of processing parameters on printed poly(ε-caprolactone) scaffolds with uniform and gradient pore architectures have been characterized with respect to fiber and pore morphology and mechanical properties. The results demonstrate the ability to tailor the fiber diameter, pore size, and porosity through modification of pressure, printing speed, and programmed fiber spacing. A model was also used to predict the compressive mechanical properties of uniform and gradient scaffolds, and it was found that modulus and yield strength declined with increasing porosity. The use of open-source 3DP technologies for printing tissue-engineering scaffolds provides a flexible system that can be readily modified at a low cost and is supported by community documentation. In this manner, the 3DP system is more accessible to the scientific community, which further facilitates the translation of these technologies toward successful tissue-engineering strategies.

Controlling the crack formation in inkjet-printed silver nanoparticle thin-films for high resolution patterning using intense pulsed light treatment

NASA Astrophysics Data System (ADS)

Gokhale, Pritesh; Mitra, Dana; Sowade, Enrico; Yoti Mitra, Kalyan; Leonel Gomes, Henrique; Ramon, Eloi; Al-Hamry, Ammar; Kanoun, Olfa; Baumann, Reinhard R.

2017-12-01

During the last years, intense pulsed light (IPL) processing has been employed and studied intensively for the drying and sintering of metal nanoparticle layers deposited by means of printing methods on flexible polymer substrates. IPL was found to be a very fast and substrate-gentle approach qualified for the field of flexible and large-area printed electronics, i.e. manufactured via roll-to-roll processing. In this contribution, IPL is used for the fine-patterning of printed silver nanoparticle layers. The patterning is obtained by induced and controlled crack formation in the thin silver layer due to the intense exposure of IPL. The crack formation is controlled by selection of the substrate material, the fine-tuning of the morphology of the silver layer and an application of a dielectric layer on top of the silver layer that acts as a stress concentrator. Careful optimization of the IPL parameters allowed to adjust the lateral width of the crack. This novel approach turned out to be a fast and reproducible high-resolution patterning process for multiple applications, e.g. to pattern the source-drain electrodes for all-inkjet-printed thin-film transistors.

3D bioprinting of structural proteins.

PubMed

Włodarczyk-Biegun, Małgorzata K; Del Campo, Aránzazu

2017-07-01

3D bioprinting is a booming method to obtain scaffolds of different materials with predesigned and customized morphologies and geometries. In this review we focus on the experimental strategies and recent achievements in the bioprinting of major structural proteins (collagen, silk, fibrin), as a particularly interesting technology to reconstruct the biochemical and biophysical composition and hierarchical morphology of natural scaffolds. The flexibility in molecular design offered by structural proteins, combined with the flexibility in mixing, deposition, and mechanical processing inherent to bioprinting technologies, enables the fabrication of highly functional scaffolds and tissue mimics with a degree of complexity and organization which has only just started to be explored. Here we describe the printing parameters and physical (mechanical) properties of bioinks based on structural proteins, including the biological function of the printed scaffolds. We describe applied printing techniques and cross-linking methods, highlighting the modifications implemented to improve scaffold properties. The used cell types, cell viability, and possible construct applications are also reported. We envision that the application of printing technologies to structural proteins will enable unprecedented control over their supramolecular organization, conferring printed scaffolds biological properties and functions close to natural systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fully Printed, Flexible, Phased Array Antenna for Lunar Surface Communication

NASA Technical Reports Server (NTRS)

Subbaraman, Harish; Hen, Ray T.; Lu, Xuejun; Chen, Maggie Yihong

2013-01-01

NASAs future exploration missions focus on the manned exploration of the Moon, Mars, and beyond, which will rely heavily on the development of a reliable communications infrastructure from planetary surface-to-surface, surface-to-orbit, and back to Earth. Flexible antennas are highly desired in many scenarios. Active phased array antennas (active PAAs) with distributed control and processing electronics at the surface of an antenna aperture offer numerous advantages for radar communications. Large-area active PAAs on flexible substrates are of particular interest in NASA s space radars due to their efficient inflatable package that can be rolled up during transportation and deployed in space. Such an inflatable package significantly reduces stowage volume and mass. Because of these performance and packaging advantages, large-area inflatable active PAAs are highly desired in NASA s surface-to-orbit and surface-to-relay communications. To address the issues of flexible electronics, a room-temperature printing process of active phased-array antennas on a flexible Kapton substrate was developed. Field effect transistors (FETs) based on carbon nanotubes (CNTs), with many unique physical properties, were successfully proved feasible for the PAA system. This innovation is a new type of fully inkjet-printable, two-dimensional, high-frequency PAA on a flexible substrate at room temperature. The designed electronic circuit components, such as the FET switches in the phase shifter, metal interconnection lines, microstrip transmission lines, etc., are all printed using a special inkjet printer. Using the developed technology, entire 1x4, 2x2, and 4x4 PAA systems were developed, packaged, and demonstrated at 5.3 GHz. Several key solutions are addressed in this work to solve the fabrication issues. The source/drain contact is developed using droplets of silver ink printed on the source/drain areas prior to applying CNT thin-film. The wet silver ink droplets allow the silver to wet the CNT thin-film area and enable good contact with the source and drain contact after annealing. A passivation layer to protect the device channel is developed by bonding a thin Kapton film on top of the device channel. This film is also used as the media for transferring the aligned CNT thin-film on the device substrate. A simple and cost-effective technique to form multilayer metal interconnections on flexible substrate is developed and demonstrated. Contact vias are formed on the second substrate prior to bonding on the first substrate. Inkjet printing is used to fill the silver ink into the via structure. The printed silver ink penetrates through the vias to contact with the contact pads on the bottom layer. It is then annealed to form a good connection. One-dimensional and two-dimensional PAAs were fabricated and characterized. In these circuits, multilayer metal interconnects were used to make a complete PAA system.

Noble Logic for Preventing Scratch on Roll-to-Roll Printed Layers in Noncontacting Transportation

NASA Astrophysics Data System (ADS)

Lee, Changwoo; Kang, Hyunkyoo; Kim, Hojoon; Shin, Keehyun

2010-05-01

The use of roll-to-roll (R2R) printed electronics is a relatively new method of mass producing flexible electronic devices while keeping production costs down. The geometrical qualities of a printed pattern, such as surface roughness and uniformity, could deteriorate. Moreover, the geometric qualities of a printed layer affect the functional qualities of a printed electronic device directly. Therefore, the functional qualities (conductivity and mobility) of a multilayer electronic device could deteriorate in the presence of a scratch defect on the printed layer. In general, a scratch on a printed pattern on a flexible substrate is induced by contact between the rolls and printed pattern in R2R printing systems. To prevent such contact, one of the best solutions is to use an air flotation unit. However, a scratch defect could be induced even though an air flotation process is used to minimize contact, because the flotation height of a moving web is affected by web tension. In this paper, we discuss an analytical model of an air-floated moving substrate. For the noncontacting transfer of a moving web without a scratch defect, a mathematical tension model has been developed by considering an induced strain due to aerodynamic forces and verified by numerical and experimental studies. Additionally, the correlation between the flotation height of an air-floated moving web and speed compensation used to control the tension are investigated. The analysis shows that tension fluctuations can cause the substrate to touch the air-flotation subsystem, which is installed to prevent contact, resulting in defects such as scratches on the printed layer. On the basis of the proposed model, a logic is developed to minimize scratch defects on R2R printed layers in noncontacting transportation. Through a guideline based on this logic, the scratched area density on R2R printed layers can be reduced by approximately 70%.

Inkjet Printing in Liquid Environments.

PubMed

Zhang, Yanzhen; Li, Dege; Liu, Yonghong; Wittstock, Gunther

2018-05-28

Inkjet printing (IJP) is an old but still vivifying technique for flexible and cost-effective printing of various kinds of functional inks. Normally, IJP can only work in gaseous environments. Here, it is shown that traditional piezoelectric IJP can be performed in liquid environments with a totally different droplet dispensing and manipulating mechanism. With the same piezoelectric nozzle, the volume of the droplets printed in a carrier liquid can be thousands of times smaller than those printed in air. Therefore, this work demonstrates a working mode of traditional IJP with a highly improved resolution opening possibilities for novel applications of the IJP technique. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Underpinnings of the Costs of Flexibility in Preschool Children: The Roles of Inhibition and Working Memory

PubMed Central

Chevalier, Nicolas; Sheffield, Tiffany D.; Nelson, Jennifer Mize; Clark, Caron A. C.; Wiebe, Sandra A.; Espy, Kimberly Andrews

2012-01-01

This study addressed the respective contributions of inhibition and working memory to two underlying components of flexibility, goal representation (as assessed by mixing costs) and switch implementation (as assessed by local costs), across the preschool period. By later preschool age (4 years 6 months and 5 years 3 months), both inhibition and working-memory performance were associated with mixing costs, but not with local costs, whereas no relation was observed earlier (3 years, 9 months). The relations of inhibition and working memory to flexibility appear to emerge late in the preschool period and are mainly driven by goal representation. PMID:22339225

Organic printed photonics: From microring lasers to integrated circuits

PubMed Central

Zhang, Chuang; Zou, Chang-Ling; Zhao, Yan; Dong, Chun-Hua; Wei, Cong; Wang, Hanlin; Liu, Yunqi; Guo, Guang-Can; Yao, Jiannian; Zhao, Yong Sheng

2015-01-01

A photonic integrated circuit (PIC) is the optical analogy of an electronic loop in which photons are signal carriers with high transport speed and parallel processing capability. Besides the most frequently demonstrated silicon-based circuits, PICs require a variety of materials for light generation, processing, modulation, and detection. With their diversity and flexibility, organic molecular materials provide an alternative platform for photonics; however, the versatile fabrication of organic integrated circuits with the desired photonic performance remains a big challenge. The rapid development of flexible electronics has shown that a solution printing technique has considerable potential for the large-scale fabrication and integration of microsized/nanosized devices. We propose the idea of soft photonics and demonstrate the function-directed fabrication of high-quality organic photonic devices and circuits. We prepared size-tunable and reproducible polymer microring resonators on a wafer-scale transparent and flexible chip using a solution printing technique. The printed optical resonator showed a quality (Q) factor higher than 4 × 105, which is comparable to that of silicon-based resonators. The high material compatibility of this printed photonic chip enabled us to realize low-threshold microlasers by doping organic functional molecules into a typical photonic device. On an identical chip, this construction strategy allowed us to design a complex assembly of one-dimensional waveguide and resonator components for light signal filtering and optical storage toward the large-scale on-chip integration of microscopic photonic units. Thus, we have developed a scheme for soft photonic integration that may motivate further studies on organic photonic materials and devices. PMID:26601256

Microfabrication of passive electronic components with printed graphene-oxide deposition

NASA Astrophysics Data System (ADS)

Sinar, Dogan; Knopf, George K.; Nikumb, Suwas

2014-03-01

Flexible electronic circuitry is an emerging technology that will significantly impact the future of healthcare and medicine, food safety inspection, environmental monitoring, and public security. Recent advances in drop-on-demand printing technology and electrically conductive inks have enabled simple electronic circuits to be fabricated on mechanically flexible polymers, paper, and bioresorbable silk. Research has shown that graphene, and its derivative formulations, can be used to create low-cost electrically conductive inks. Graphene is a one atom thick two-dimensional layer composed of carbon atoms arranged in a hexagonal lattice forming a material with very high fracture strength, high Young's Modulus, and low electrical resistance. Non-conductive graphene-oxide (GO) inks can also be synthesized from inexpensive graphite powders. Once deposited on the flexible substrate the electrical conductivity of the printed GO microcircuit traces can be restored through thermal reduction. In this paper, a femtosecond laser with a wavelength of 775nm and pulse width of 120fs is used to transform the non-conductive printed GO film into electrically conductive oxygen reduced graphene-oxide (rGO) passive electronic components by the process of laser assisted thermal reduction. The heat affected zone produced during the process was minimized because of the femtosecond pulsed laser. The degree of conductivity exhibited by the microstructure is directly related to the laser power level and exposure time. Although rGO films have higher resistances than pristine graphene, the ability to inkjet print capacitive elements and modify local resistive properties provides for a new method of fabricating sensor microcircuits on a variety of substrate surfaces.

Organic printed photonics: From microring lasers to integrated circuits.

PubMed

Zhang, Chuang; Zou, Chang-Ling; Zhao, Yan; Dong, Chun-Hua; Wei, Cong; Wang, Hanlin; Liu, Yunqi; Guo, Guang-Can; Yao, Jiannian; Zhao, Yong Sheng

2015-09-01

A photonic integrated circuit (PIC) is the optical analogy of an electronic loop in which photons are signal carriers with high transport speed and parallel processing capability. Besides the most frequently demonstrated silicon-based circuits, PICs require a variety of materials for light generation, processing, modulation, and detection. With their diversity and flexibility, organic molecular materials provide an alternative platform for photonics; however, the versatile fabrication of organic integrated circuits with the desired photonic performance remains a big challenge. The rapid development of flexible electronics has shown that a solution printing technique has considerable potential for the large-scale fabrication and integration of microsized/nanosized devices. We propose the idea of soft photonics and demonstrate the function-directed fabrication of high-quality organic photonic devices and circuits. We prepared size-tunable and reproducible polymer microring resonators on a wafer-scale transparent and flexible chip using a solution printing technique. The printed optical resonator showed a quality (Q) factor higher than 4 × 10(5), which is comparable to that of silicon-based resonators. The high material compatibility of this printed photonic chip enabled us to realize low-threshold microlasers by doping organic functional molecules into a typical photonic device. On an identical chip, this construction strategy allowed us to design a complex assembly of one-dimensional waveguide and resonator components for light signal filtering and optical storage toward the large-scale on-chip integration of microscopic photonic units. Thus, we have developed a scheme for soft photonic integration that may motivate further studies on organic photonic materials and devices.

Inkjet-Printed Small-Molecule Organic Light-Emitting Diodes: Halogen-Free Inks, Printing Optimization, and Large-Area Patterning.

PubMed

Zhou, Lu; Yang, Lei; Yu, Mengjie; Jiang, Yi; Liu, Cheng-Fang; Lai, Wen-Yong; Huang, Wei

2017-11-22

Manufacturing small-molecule organic light-emitting diodes (OLEDs) via inkjet printing is rather attractive for realizing high-efficiency and long-life-span devices, yet it is challenging. In this paper, we present our efforts on systematical investigation and optimization of the ink properties and the printing process to enable facile inkjet printing of conjugated light-emitting small molecules. Various factors on influencing the inkjet-printed film quality during the droplet generation, the ink spreading on the substrates, and its solidification processes have been systematically investigated and optimized. Consequently, halogen-free inks have been developed and large-area patterning inkjet printing on flexible substrates with efficient blue emission has been successfully demonstrated. Moreover, OLEDs manufactured by inkjet printing the light-emitting small molecules manifested superior performance as compared with their corresponding spin-cast counterparts.

Development of Flexible Visual Recognition Memory in Human Infants

ERIC Educational Resources Information Center

Robinson, Astri J.; Pascalis, Olivier

2004-01-01

Research using the visual paired comparison task has shown that visual recognition memory across changing contexts is dependent on the integrity of the hippocampal formation in human adults and in monkeys. The acquisition of contextual flexibility may contribute to the change in memory performance that occurs late in the first year of life. To…

All-inkjet-printed flexible ZnO micro photodetector for a wearable UV monitoring device

NASA Astrophysics Data System (ADS)

Tran, Van-Thai; Wei, Yuefan; Yang, Hongyi; Zhan, Zhaoyao; Du, Hejun

2017-03-01

Fabrication of small-sized patterns of inorganic semiconductor onto flexible substrates is a major concern when manufacturing wearable devices for measuring either biometric or environmental parameters. In this study, micro-sized flexible ZnO UV photodetectors have been thoroughly prepared by a facile inkjet printing technology and followed with heat treatments. A simple ink recipe of zinc acetate precursor solution was investigated. It is found that the substrate temperature during zinc precursor ink depositing has significant effects on ZnO pattern shape, film morphology, and crystallization. The device fabricated from the additive manufacturing approach has good bendability, Ohmic contact, short response time as low as 0.3 s, and high on/off ratio of 3525. We observed the sensor’s dependence of response/decay time by the illuminating UV light intensity. The whole process is based on additive manufacturing which has many benefits such as rapid prototyping, saving material, being environmentally friendly, and being capable of creating high-resolution patterns. In addition, this method can be applied to flexible substrates, which makes the device more applicable for applications requiring flexibility such as wearable devices. The proposed all-inkjet-printing approach for a micro-sized ZnO UV photodetector would significantly simplify the fabrication process of micro-sized inorganic semiconductor-based devices. A potential application is real-time monitoring of UV light exposure to warn users about unsafe direct sunlight to implement suitable avoidance solutions.

A stencil printed, high energy density silver oxide battery using a novel photopolymerizable poly(acrylic acid) separator.

PubMed

Braam, Kyle; Subramanian, Vivek

2015-01-27

A novel photopolymerized poly(acrylic acid) separator is demonstrated in a printed, high-energy-density silver oxide battery. The printed battery demonstrates a high capacity of 5.4 mA h cm(-2) at a discharge current density of 2.75 mA cm(-2) (C/2 rate) while delivering good mechanical flexibility and robustness. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Printed Organic Circuit System for Wearable Amperometric Electrochemical Sensors.

PubMed

Shiwaku, Rei; Matsui, Hiroyuki; Nagamine, Kuniaki; Uematsu, Mayu; Mano, Taisei; Maruyama, Yuki; Nomura, Ayako; Tsuchiya, Kazuhiko; Hayasaka, Kazuma; Takeda, Yasunori; Fukuda, Takashi; Kumaki, Daisuke; Tokito, Shizuo

2018-04-23

Wearable sensor device technologies, which enable continuous monitoring of biological information from the human body, are promising in the fields of sports, healthcare, and medical applications. Further thinness, light weight, flexibility and low-cost are significant requirements for making the devices attachable onto human tissues or clothes like a patch. Here we demonstrate a flexible and printed circuit system consisting of an enzyme-based amperometric sensor, feedback control and amplification circuits based on organic thin-film transistors. The feedback control and amplification circuits based on pseudo-CMOS inverters were successfuly integrated by printing methods on a plastic film. This simple system worked very well like a potentiostat for electrochemical measurements, and enabled the quantitative and real-time measurement of lactate concentration with high sensitivity of 1 V/mM and a short response time of a hundred seconds.

Solar array strip and a method for forming the same

NASA Technical Reports Server (NTRS)

Mueller, R. L.; Yasui, R. K. (Inventor)

1979-01-01

A flexible solar array strip is formed by providing printed circuitry between flexible layers of a nonconductive material, depositing solder pads on the printed circuitry, and storing the resulting substrate on a drum from which it is then withdrawn and advanced along a linear path. Solderless solar cells are serially transported into engagement with the pads and are infrared radiation to melt the solder and attach the cells to the circuitry. Excess flux is cleaned from the solar cells which are then encapsulated in a protective coating. The resulting array is then wound on a drum.

Investigations on the effects of electrode materials on the device characteristics of ferroelectric memory thin film transistors fabricated on flexible substrates

NASA Astrophysics Data System (ADS)

Yang, Ji-Hee; Yun, Da-Jeong; Seo, Gi-Ho; Kim, Seong-Min; Yoon, Myung-Han; Yoon, Sung-Min

2018-03-01

For flexible memory device applications, we propose memory thin-film transistors using an organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] gate insulator and an amorphous In-Ga-Zn-O (a-IGZO) active channel. The effects of electrode materials and their deposition methods on the characteristics of memory devices exploiting the ferroelectric field effect were investigated for the proposed ferroelectric memory thin-film transistors (Fe-MTFTs) at flat and bending states. It was found that the plasma-induced sputtering deposition and mechanical brittleness of the indium-tin oxide (ITO) markedly degraded the ferroelectric-field-effect-driven memory window and bending characteristics of the Fe-MTFTs. The replacement of ITO electrodes with metal aluminum (Al) electrodes prepared by plasma-free thermal evaporation greatly enhanced the memory device characteristics even under bending conditions owing to their mechanical ductility. Furthermore, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) was introduced to achieve robust bending performance under extreme mechanical stress. The Fe-MTFTs using PEDOT:PSS source/drain electrodes were successfully fabricated and showed the potential for use as flexible memory devices. The suitable choice of electrode materials employed for the Fe-MTFTs is concluded to be one of the most important control parameters for highly functional flexible Fe-MTFTs.

Design of a smart ECG garment based on conductive textile electrode and flexible printed circuit board.

PubMed

Cai, Zhipeng; Luo, Kan; Liu, Chengyu; Li, Jianqing

2017-08-09

A smart electrocardiogram (ECG) garment system was designed for continuous, non-invasive and comfortable ECG monitoring, which mainly consists of four components: Conductive textile electrode, garment, flexible printed circuit board (FPCB)-based ECG processing module and android application program. Conductive textile electrode and FPCB-based ECG processing module (6.8 g, 55 mm × 53 mm × 5 mm) are identified as two key techniques to improve the system's comfort and flexibility. Preliminary experimental results verified that the textile electrodes with circle shape, 40 mm size in diameter, and 5 mm thickness sponge are best suited for the long-term ECG monitoring application. The tests on the whole system confirmed that the designed smart garment can obtain long-term ECG recordings with high signal quality.

Writing Learning Materials for Adult Literacy and Basic Education Students for Flexible Delivery: Some Challenges.

ERIC Educational Resources Information Center

Kindler, Jan

1998-01-01

Describes development of CD-ROM and print materials designed for learners with low literacy levels. Explains the importance of group work, incorporation of different learning styles, and the benefits of flexible delivery. (SK)

A bio-enabled maximally mild layer-by-layer Kapton surface modification approach for the fabrication of all-inkjet-printed flexible electronic devices

PubMed Central

Fang, Yunnan; Hester, Jimmy G. D.; Su, Wenjing; Chow, Justin H.; Sitaraman, Suresh K.; Tentzeris, Manos M.

2016-01-01

A bio-enabled, environmentally-friendly, and maximally mild layer-by-layer approach has been developed to surface modify inherently hydrophobic Kapton HN substrates to allow for great printability of both water- and organic solvent-based inks thus facilitating the full-inkjet-printing of flexible electronic devices. Different from the traditional Kapton surface modification approaches which are structure-compromising and use harsh conditions to target, and oxidize and/or remove part of, the surface polyimide of Kapton, the present Kapton surface modification approach targeted the surface electric charges borne by its additive particles, and was not only the first to utilize environmentally-friendly clinical biomolecules to build up a thin film of protamine-heparin complex on Kapton, but also the first to be conducted under minimally destructive and maximally mild conditions. Besides, for electrically charged ink particles, the present surface modification method can enhance the uniformity of the inkjet-printed films by reducing the “coffee ring effect”. As a proof-of-concept demonstration, reduced graphene oxide-based gas sensors, which were flexible, ultra-lightweight, and miniature-sized, were fully-inkjet-printed on surface modified Kapton HN films and tested for their sensitivity to dimethyl methylphosphonate (a nerve agent simulant). Such fabricated sensors survived a Scotch-tape peel test and were found insensitive to repeated bending to a small 0.5 cm radius. PMID:28008987

Nanoalloy Printed and Pulse-Laser Sintered Flexible Sensor Devices with Enhanced Stability and Materials Compatibility.

PubMed

Zhao, Wei; Rovere, Thomas; Weerawarne, Darshana; Osterhoudt, Gavin; Kang, Ning; Joseph, Pharrah; Luo, Jin; Shim, Bonggu; Poliks, Mark; Zhong, Chuan-Jian

2015-06-23

While conformal and wearable devices have become one of the most desired formats for printable electronics, it is challenging to establish a scalable process that produces stable conductive patterns but also uses substrates compatible with widely available wearable materials. Here, we describe findings of an investigation of a nanoalloy ink printed and pulsed-laser sintered conductive patterns as flexible functional devices with enhanced stability and materials compatibility. While nanoparticle inks are desired for printable electronics, almost all existing nanoparticle inks are based on single-metal component, which, as an electronic element, is limited by its inherent stabilities of the metal such as propensity of metal oxidation and mobility of metal ions, especially in sintering processes. The work here has demonstrated the first example in exploiting plasmonic coupling of nanoalloys and pulsed-laser energy with controllable thermal penetration. The experimental and theoretical results have revealed clear correlation between the pulsed laser parameters and the nanoalloy structural characteristics. The superior performance of the resulting flexible sensor device, upon imparting nanostructured sensing materials, for detecting volatile organic compounds has significant implications to developing stable and wearable sensors for monitoring environmental pollutants and breath biomarkers. This simple "nanoalloy printing-laser sintering-nanostructure printing" process is entirely general to many different sensor devices and nanostructured sensing materials, enabling the ability to easily construct sophisticated sensor array.

A bio-enabled maximally mild layer-by-layer Kapton surface modification approach for the fabrication of all-inkjet-printed flexible electronic devices

NASA Astrophysics Data System (ADS)

Fang, Yunnan; Hester, Jimmy G. D.; Su, Wenjing; Chow, Justin H.; Sitaraman, Suresh K.; Tentzeris, Manos M.

2016-12-01

A bio-enabled, environmentally-friendly, and maximally mild layer-by-layer approach has been developed to surface modify inherently hydrophobic Kapton HN substrates to allow for great printability of both water- and organic solvent-based inks thus facilitating the full-inkjet-printing of flexible electronic devices. Different from the traditional Kapton surface modification approaches which are structure-compromising and use harsh conditions to target, and oxidize and/or remove part of, the surface polyimide of Kapton, the present Kapton surface modification approach targeted the surface electric charges borne by its additive particles, and was not only the first to utilize environmentally-friendly clinical biomolecules to build up a thin film of protamine-heparin complex on Kapton, but also the first to be conducted under minimally destructive and maximally mild conditions. Besides, for electrically charged ink particles, the present surface modification method can enhance the uniformity of the inkjet-printed films by reducing the “coffee ring effect”. As a proof-of-concept demonstration, reduced graphene oxide-based gas sensors, which were flexible, ultra-lightweight, and miniature-sized, were fully-inkjet-printed on surface modified Kapton HN films and tested for their sensitivity to dimethyl methylphosphonate (a nerve agent simulant). Such fabricated sensors survived a Scotch-tape peel test and were found insensitive to repeated bending to a small 0.5 cm radius.

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

NASA Astrophysics Data System (ADS)

Ghoneim, M. T.; Hussain, M. M.

2015-08-01

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ˜260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.

Fabrication of In(0.75)Zn(1.5)Sn(1.0) (IZTO) Thin-Film Transistors Using Solution-Processable Materials and PZT Inkjet-Printing.

PubMed

Lee, Tai-Kuang; Liuand, Chao-Te; Lee, Wen-Hsi

2017-01-01

Recently, Thin Film Transistors (TFTs) have been studied widely because of potential applications in low cost, low-temperature process and flexible displays. They can be fabricated by easy processes based on solution methods. But the mobility of organic TFTs is lower and the threshold voltage is higher than amorphous Si TFTs. In order to enhance the channel mobility and satisfy with the requirement of low-cost fabrication, we prepare a low-cost, mask-free, reduced material wastage, deposited technology using transparent, directly printable, air-stable semiconductor slurries and dielectric solutions. In our investigations, we attempt to obtain a high performance and low-cost TFT via preparing materials, designing device structure, and using PZT inkjet-printing technology. A stable and non-precipitated metal oxide ink with appropriate doping was prepared for the fabrication of an InxZn1.5Sn1.0 (IZTO) by PZT inkjet-printing. The soluble direct-printing process is a powerful tool for material research and implies that the printable materials and the printing technology enable the use of all-printed low-cost flexible displays and other transparent electronic applications. Transparent materials including dielectric PVP, conductive carbon nanotube (CNT) and active IZTO were employed into the fabrication of our PZT inkjet-printing process. After annealed at 180 °C, The experimental all-printed TFT exhibit the carrier mobility of 0.194 cm2/Vs, sub-threshold slope of 20 V/decade, and the threshold voltage of 5 V, initially. All-inkjet-printed films have great transparency, potentially in transparent electronics and the transmittance pattern in visible part of the spectrum (400–700 nm) is over 80%.

Dual-extrusion 3D printing of anatomical models for education.

PubMed

Smith, Michelle L; Jones, James F X

2018-01-01

Two material 3D printing is becoming increasingly popular, inexpensive and accessible. In this paper, freely available printable files and dual extrusion fused deposition modelling were combined to create a number of functional anatomical models. To represent muscle and bone FilaFlex 3D flexible filament and polylactic acid (PLA) filament were extruded respectively via a single 0.4 mm nozzle using a Big Builder printer. For each filament, cubes (5 mm 3 ) were printed and analyzed for X, Y, and Z accuracy. The PLA printed cubes resulted in errors averaging just 1.2% across all directions but for FilaFlex 3D printed cubes the errors were statistically significantly greater (average of 3.2%). As an exemplar, a focus was placed on the muscles, bones and cartilage of upper airway and neck. The resulting single prints combined flexible and hard structures. A single print model of the vocal cords was constructed which permitted movement of the arytenoids on the cricoid cartilage and served to illustrate the action of intrinsic laryngeal muscles. As University libraries become increasingly engaged in offering inexpensive 3D printing services it may soon become common place for both student and educator to access websites, download free models or 3D body parts and only pay the costs of print consumables. Novel models can be manufactured as dissectible, functional multi-layered units and offer rich possibilities for sectional and/or reduced anatomy. This approach can liberate the anatomist from constraints of inflexible hard models or plastinated specimens and engage in the design of class specific models of the future. Anat Sci Educ 11: 65-72. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

Analytical study on web deformation by tension in roll-to-roll printing process

NASA Astrophysics Data System (ADS)

Kang, Y. S.; Hong, M. S.; Lee, S. H.; Jeon, Y. H.; Kang, D.; Lee, N. K.; Lee, M. G.

2017-08-01

Recently, flexible devices have gained high intentions for flexible display, Radio Frequency Identification (RFID), bio-sensor and so on. For manufacturing of the flexible devices, roll-to-roll process is a good candidate because of its low production cost and high productivity. Flexible substrate has a non-uniform deformation distribution by tension. Because the roll-to-roll process carries out a number of overlay printing processes, the deformation affect overlay printing precision and printable areas. In this study, the deformation of flexible substrate was analyzed by using finite element analysis and it was verified through experiments. More deformation occurred in the middle region in the direction parallel to rolling of the flexible substrate. It is confirmed through experiments and analysis that deformation occurs less at the both ends than in the middle region. Based on these results, a hourglass roll is proposed as a mechanical design of the roll to compensate the non-uniform deformation of the flexible substrate. In the hourglass roll, high stiffness material is used in the core and low stiffness material such as an elastic material is wrapped. The diameter of the core roll was designed to be the minimum at the middle and the maximum at both ends. We tried to compensate the non-uniform deformation distribution of the flexible substrate by using the variation of the contact stiffness between the roll and the flexible substrate. Deformation distribution of flexible substrates was confirmed by finite element analysis by applying hourglass roll shape. In the analysis when using the hourglass roll, it is confirmed that the stress distribution is compensated by about 70% and the strain distribution is compensated by about 67% compared to the case using the hourglass roll. To verify the compensation of the non-uniform deformation distribution due to the tension, deformation measurement experiment when using the proposed hourglass roll was carried out. Experiments have shown that the distribution of deformation is compensated by about 34%. From the results, we verified the performance of the proposed.

Discrete Resource Allocation in Visual Working Memory

ERIC Educational Resources Information Center

Barton, Brian; Ester, Edward F.; Awh, Edward

2009-01-01

Are resources in visual working memory allocated in a continuous or a discrete fashion? On one hand, flexible resource models suggest that capacity is determined by a central resource pool that can be flexibly divided such that items of greater complexity receive a larger share of resources. On the other hand, if capacity in working memory is…

The nature of expertise in fingerprint examiners.

PubMed

Busey, Thomas A; Parada, Francisco J

2010-04-01

Latent print examinations involve a complex set of psychological and cognitive processes. This article summarizes existing work that has addressed how training and experience creates changes in latent print examiners. Experience appears to improve overall accuracy, increase visual working memory, and lead to configural processing of upright fingerprints. Experts also demonstrate a narrower visual filter and, as a group, tend to show greater consistency when viewing ink prints. These findings address recent criticisms of latent print evidence, but many open questions still exist. Cognitive scientists are well positioned to conduct studies that will improve the training and practices of latent print examiners, and suggestions for becoming involved in fingerprint research are provided.

TU-H-BRC-08: Use and Validation of Flexible 3D Printed Tissue Compensators for Post-Mastectomy Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craft, D; Kry, S; Salehpour, M

Purpose: Patient-specific tissue equivalent compensators can be used for post-mastectomy radiation therapy (PMRT) to achieve homogenous dose distributions with single-field treatments. However, current fabrication methods are time consuming and expensive. 3D-printing technology could overcome these limitations. The purposes of this study were to [1] evaluate materials for 3D-printed compensators [2] design and print a compensator to achieve a uniform thickness to a clinical target volume (CTV), and [3] demonstrate that a single-field electron compensator plan is a clinically feasible treatment option for PMRT. Methods: Blocks were printed with three materials; print accuracy, density, Hounsfield units (HU), and percent depth dosesmore » (PDD) were evaluated. For a CT scan of an anthropomorphic phantom, we used a ray-tracing method to design a compensator that achieved uniform thickness from compensator surface to CTV. The compensator was printed with flexible tissue equivalent material whose physical and radiological properties were most similar to soft tissue. A single-field electron compensator plan was designed and compared with two standard-of-care techniques. The compensator plan was validated with thermoluminescent dosimeter (TLD) measurements. Results: We identified an appropriate material for 3D-printed compensators that had high print accuracy (99.6%) and was similar to soft tissue; density was 1.04, HU was - 45 ± 43, and PDD curves agreed with clinical curves within 3 mm. We designed and printed a compensator that conformed well to the phantom surface and created a uniform thickness to the CTV. In-house fabrication was simple and inexpensive (<$75). Compared with the two standard plans, the compensator plan resulted in overall more homogeneous dose distributions and performed similarly in terms of lung/heart doses and 90% isodose coverage of the CTV. TLD measurements agreed well with planned doses (within 5 %). Conclusions: We have demonstrated that 3D-printed compensators make single-field electron therapy a clinically feasible treatment option for PMRT.« less

Flow-Directed Crystallization for Printed Electronics.

PubMed

Qu, Ge; Kwok, Justin J; Diao, Ying

2016-12-20

The solution printability of organic semiconductors (OSCs) represents a distinct advantage for materials processing, enabling low-cost, high-throughput, and energy-efficient manufacturing with new form factors that are flexible, stretchable, and transparent. While the electronic performance of OSCs is not comparable to that of crystalline silicon, the solution processability of OSCs allows them to complement silicon by tackling challenging aspects for conventional photolithography, such as large-area electronics manufacturing. Despite this, controlling the highly nonequilibrium morphology evolution during OSC printing remains a challenge, hindering the achievement of high electronic device performance and the elucidation of structure-property relationships. Many elegant morphological control methodologies have been developed in recent years including molecular design and novel processing approaches, but few have utilized fluid flow to control morphology in OSC thin films. In this Account, we discuss flow-directed crystallization as an effective strategy for controlling the crystallization kinetics during printing of small molecule and polymer semiconductors. Introducing the concept of flow-directed crystallization to the field of printed electronics is inspired by recent advances in pharmaceutical manufacturing and flow processing of flexible-chain polymers. Although flow-induced crystallization is well studied in these areas, previous findings may not apply directly to the field of printed electronics where the molecular structures (i.e., rigid π-conjugated backbone decorated with flexible side chains) and the intermolecular interactions (i.e., π-π interactions, quadrupole interactions) of OSCs differ substantially from those of pharmaceuticals or flexible-chain polymers. Another critical difference is the important role of solvent evaporation in open systems, which defines the flow characteristics and determines the crystallization kinetics and pathways. In other words, flow-induced crystallization is intimately coupled with the mass transport processes driven by solvent evaporation during printing. In this Account, we will highlight these distinctions of flow-directed crystallization for printed electronics. In the context of solution printing of OSCs, the key issue that flow-directed crystallization addresses is the kinetics mismatch between crystallization and various transport processes during printing. We show that engineering fluid flows can tune the kinetics of OSC crystallization by expediting the nucleation and crystal growth processes, significantly enhancing thin film morphology and device performance. For small molecule semiconductors, nucleation can be enhanced and patterned by directing the evaporative flux via contact line engineering, and defective crystal growth can be alleviated by enhancing mass transport to yield significantly improved coherence length and reduced grain boundaries. For conjugated polymers, extensional and shear flow can expedite nucleation through flow-induced conformation change, facilitating the control of microphase separation, degree of crystallinity, domain alignment, and percolation. Although the nascent concept of flow-directed solution printing has not yet been widely adopted in the field of printed electronics, we anticipate that it can serve as a platform technology in the near future for improving device performance and for systematically tuning thin film morphology to construct structure-property relationships. From a fundamental perspective, it is imperative to develop a better understanding of the effects of fluid flow and mass transport on OSC crystallization as these processes are ubiquitous across all solution processing techniques and can critically impact charge transport properties.

Design of a CMOS readout circuit on ultra-thin flexible silicon chip for printed strain gauges

NASA Astrophysics Data System (ADS)

Elsobky, Mourad; Mahsereci, Yigit; Keck, Jürgen; Richter, Harald; Burghartz, Joachim N.

2017-09-01

Flexible electronics represents an emerging technology with features enabling several new applications such as wearable electronics and bendable displays. Precise and high-performance sensors readout chips are crucial for high quality flexible electronic products. In this work, the design of a CMOS readout circuit for an array of printed strain gauges is presented. The ultra-thin readout chip and the printed sensors are combined on a thin Benzocyclobutene/Polyimide (BCB/PI) substrate to form a Hybrid System-in-Foil (HySiF), which is used as an electronic skin for robotic applications. Each strain gauge utilizes a Wheatstone bridge circuit, where four Aerosol Jet® printed meander-shaped resistors form a full-bridge topology. The readout chip amplifies the output voltage difference (about 5 mV full-scale swing) of the strain gauge. One challenge during the sensor interface circuit design is to compensate for the relatively large dc offset (about 30 mV at 1 mA) in the bridge output voltage so that the amplified signal span matches the input range of an analog-to-digital converter (ADC). The circuit design uses the 0. 5 µm mixed-signal GATEFORESTTM technology. In order to achieve the mechanical flexibility, the chip fabrication is based on either back thinned wafers or the ChipFilmTM technology, which enables the manufacturing of silicon chips with a thickness of about 20 µm. The implemented readout chip uses a supply of 5 V and includes a 5-bit digital-to-analog converter (DAC), a differential difference amplifier (DDA), and a 10-bit successive approximation register (SAR) ADC. The circuit is simulated across process, supply and temperature corners and the simulation results indicate excellent performance in terms of circuit stability and linearity.

High-Resolution Graphene Films for Electrochemical Sensing via Inkjet Maskless Lithography.

PubMed

Hondred, John A; Stromberg, Loreen R; Mosher, Curtis L; Claussen, Jonathan C

2017-10-24

Solution-phase printing of nanomaterial-based graphene inks are rapidly gaining interest for fabrication of flexible electronics. However, scalable manufacturing techniques for high-resolution printed graphene circuits are still lacking. Here, we report a patterning technique [i.e., inkjet maskless lithography (IML)] to form high-resolution, flexible, graphene films (line widths down to 20 μm) that significantly exceed the current inkjet printing resolution of graphene (line widths ∼60 μm). IML uses an inkjet printed polymer lacquer as a sacrificial pattern, viscous spin-coated graphene, and a subsequent graphene lift-off to pattern films without the need for prefabricated stencils, templates, or cleanroom technology (e.g., photolithography). Laser annealing is employed to increase conductivity on thermally sensitive, flexible substrates [polyethylene terephthalate (PET)]. Laser annealing and subsequent platinum nanoparticle deposition substantially increases the electroactive nature of graphene as illustrated by electrochemical hydrogen peroxide (H 2 O 2 ) sensing [rapid response (5 s), broad linear sensing range (0.1-550 μm), high sensitivity (0.21 μM/μA), and low detection limit (0.21 μM)]. Moreover, high-resolution, complex graphene circuits [i.e., interdigitated electrodes (IDE) with varying finger width and spacing] were created with IML and characterized via potassium chloride (KCl) electrochemical impedance spectroscopy (EIS). Results indicated that sensitivity directly correlates to electrode feature size as the IDE with the smallest finger width and spacing (50 and 50 μm) displayed the largest response to changes in KCl concentration (∼21 kΩ). These results indicate that the developed IML patterning technique is well-suited for rapid, solution-phase graphene film prototyping on flexible substrates for numerous applications including electrochemical sensing.

Flexible Regenerative Nanoelectronics for Advanced Peripheral Neural Interfaces

DTIC Science & Technology

2017-10-01

these materials will be developed based on 3D printing . Page 4 Task 3. Construct nerve guidance scaffolds comprising of embedded mesh electrodes with...Develop photo mask patterning methods. 1-9 In progress 50% Subtask 2.2.2. Develop 3D printing patterning methods. 9-18 9/1/2017 Milestone(s...research into patterning techniques, we found that 10% gelatin methacrylate (GelMA) base gel was the best for performing 3D printing of the gels

A flexible-dose dispenser for immediate and extended release 3D printed tablets.

PubMed

Pietrzak, Katarzyna; Isreb, Abdullah; Alhnan, Mohamed A

2015-10-01

The advances in personalised medicine increased the demand for a fast, accurate and reliable production method of tablets that can be digitally controlled by healthcare staff. A flexible dose tablet system is presented in this study that proved to be suitable for immediate and extended release tablets with a realistic drug loading and an easy-to-swallow tablet design. The method bridges the affordable and digitally controlled Fused Deposition Modelling (FDM) 3D printing with a standard pharmaceutical manufacturing process, Hot Melt Extrusion (HME). The reported method was compatible with three methacrylic polymers (Eudragit RL, RS and E) as well as a cellulose-based one (hydroxypropyl cellulose, HPC SSL). The use of a HME based pharmaceutical filament preserved the linear relationship between the mass and printed volume and was utilized to digitally control the dose via an input from computer software with dose accuracy in the range of 91-95%. Higher resolution printing quality doubled the printing time, but showed a little effect on in vitro release pattern of theophylline and weight accuracy. Physical characterization studies indicated that the majority of the model drug (theophylline) in the 3D printed tablet exists in a crystal form. Owing to the small size, ease of use and the highly adjustable nature of FDM 3D printers, the method holds promise for future individualised treatment. Copyright © 2015. Published by Elsevier B.V.

Children's Recall of Television and Print News: A Media Comparison Study.

ERIC Educational Resources Information Center

van der Molen, Juliette H. Walma; van der Voort, Tom H. A.

1997-01-01

Results of a cued-recall test taken by 152 Dutch fourth and sixth graders indicate that children who watch a children's news show on television recall more than those who read the same news in print regardless of reading proficiency or expectation of a memory test. (SLD)

All-Solution-Processed Metal-Oxide-Free Flexible Organic Solar Cells with Over 10% Efficiency.

PubMed

Song, Wei; Fan, Xi; Xu, Bingang; Yan, Feng; Cui, Huiqin; Wei, Qiang; Peng, Ruixiang; Hong, Ling; Huang, Jiaming; Ge, Ziyi

2018-05-16

All-solution-processing at low temperatures is important and desirable for making printed photovoltaic devices and also offers the possibility of a safe and cost-effective fabrication environment for the devices. Herein, an all-solution-processed flexible organic solar cell (OSC) using poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) electrodes is reported. The all-solution-processed flexible devices yield the highest power conversion efficiency of 10.12% with high fill factor of over 70%, which is the highest value for metal-oxide-free flexible OSCs reported so far. The enhanced performance is attributed to the newly developed gentle acid treatment at room temperature that enables a high-performance PEDOT:PSS/plastic underlying substrate with a matched work function (≈4.91 eV), and the interface engineering that endows the devices with better interface contacts and improved hole mobility. Furthermore, the flexible devices exhibit an excellent mechanical flexibility, as indicated by a high retention (≈94%) of the initial efficiency after 1000 bending cycles. This work provides a simple route to fabricate high-performance all-solution-processed flexible OSCs, which is important for the development of printing, blading, and roll-to-roll technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Route Descriptions by Visually Impaired and Sighted Children from Memory and from Maps.

ERIC Educational Resources Information Center

Edwards, Rachel; Ungar, Simon; Blades, Mark

1998-01-01

This study evaluated descriptions, either from memory or by using a map (print or tactile), of 12 visually impaired and 12 sighted elementary grade children of two routes around their schools. Descriptions from maps were generally poorer than those from memory. Qualitative differences were also found between descriptions of visually impaired and…

A Rising Tide of Digitization--The Ohio Memory Project

ERIC Educational Resources Information Center

Kupfer, Shannon

2010-01-01

In 2009, after a year of planning and preparation, the second generation of Ohio Memory was launched. A collaborative effort of the Ohio Historical Society (OHS) and the State Library of Ohio, Ohio Memory is a repository for more than 75,000 digital items, including photographs, journals, and other manuscript materials, as well as print documents…

Dual-Extrusion 3D Printing of Anatomical Models for Education

ERIC Educational Resources Information Center

Smith, Michelle L.; Jones, James F. X.

2018-01-01

Two material 3D printing is becoming increasingly popular, inexpensive and accessible. In this paper, freely available printable files and dual extrusion fused deposition modelling were combined to create a number of functional anatomical models. To represent muscle and bone FilaFlex[superscript 3D] flexible filament and polylactic acid (PLA)…

An Integer Programming-Based Generalized Vehicle Routing Approach for Printed Circuit Board Assembly Optimization

ERIC Educational Resources Information Center

Seth, Anupam

2009-01-01

Production planning and scheduling for printed circuit, board assembly has so far defied standard operations research approaches due to the size and complexity of the underlying problems, resulting in unexploited automation flexibility. In this thesis, the increasingly popular collect-and-place machine configuration is studied and the assembly…

Printing Smart Designs of Light Emitting Devices with Maintained Textile Properties †

PubMed Central

Verboven, Inge; Stryckers, Jeroen; Mecnika, Viktorija; Vandevenne, Glen; Jose, Manoj

2018-01-01

To maintain typical textile properties, smart designs of light emitting devices are printed directly onto textile substrates. A first approach shows improved designs for alternating current powder electroluminescence (ACPEL) devices. A configuration with the following build-up, starting from the textile substrate, was applied using the screen printing technique: silver (10 µm)/barium titanate (10 µm)/zinc-oxide (10 µm) and poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (10 µm). Textile properties such as flexibility, drapability and air permeability are preserved by implementing a pixel-like design of the printed layers. Another route is the application of organic light emitting devices (OLEDs) fabricated out of following layers, also starting from the textile substrate: polyurethane or acrylate (10–20 µm) as smoothing layer/silver (200 nm)/poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (35 nm)/super yellow (80 nm)/calcium/aluminum (12/17 nm). Their very thin nm-range layer thickness, preserving the flexibility and drapability of the substrate, and their low working voltage, makes these devices the possible future in light-emitting wearables. PMID:29438276

Fabrication and Characterization of Flexible and Miniaturized Humidity Sensors Using Screen-Printed TiO2 Nanoparticles as Sensitive Layer

PubMed Central

Dubourg, Georges; Segkos, Apostolos; Katona, Jaroslav; Radović, Marko; Savić, Slavica; Crnojević-Bengin, Vesna

2017-01-01

This paper describes the fabrication and the characterization of an original example of a miniaturized resistive-type humidity sensor, printed on flexible substrate in a large-scale manner. The fabrication process involves laser ablation for the design of interdigitated electrodes on PET (Poly-Ethylene Terephthalate) substrate and a screen-printing process for the deposition of the sensitive material, which is based on TiO2 nanoparticles. The laser ablation process was carefully optimized to obtain micro-scale and well-resolved electrodes on PET substrate. A functional paste based on cellulose was prepared in order to allow the precise screen-printing of the TiO2 nanoparticles as sensing material on the top of the electrodes. The current against voltage (I–V) characteristic of the sensor showed good linearity and potential for low-power operation. The results of a humidity-sensing investigation and mechanical testing showed that the fabricated miniaturized sensors have excellent mechanical stability, sensing characteristics, good repeatability, and relatively fast response/recovery times operating at room temperature. PMID:28800063

Three-dimensional bio-printing.

PubMed

Gu, Qi; Hao, Jie; Lu, YangJie; Wang, Liu; Wallace, Gordon G; Zhou, Qi

2015-05-01

Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.

Multi-stage responsive 4D printed smart structure through varying geometric thickness of shape memory polymer

NASA Astrophysics Data System (ADS)

Teoh, Joanne Ee Mei; Zhao, Yue; An, Jia; Chua, Chee Kai; Liu, Yong

2017-12-01

Shape memory polymers (SMPs) have gained a presence in additive manufacturing due to their role in 4D printing. They can be printed either in multi-materials for multi-stage shape recovery or in a single material for single-stage shape recovery. When printed in multi-materials, material or material-based design is used as a controlling factor for multi-stage shape recovery. However, when printed in a single material, it is difficult to design multi-stage shape recovery due to the lack of a controlling factor. In this research, we explore the use of geometric thickness as a controlling factor to design smart structures possessing multi-stage shape recovery using a single SMP. L-shaped hinges with a thickness ranging from 0.3-2 mm were designed and printed in four different SMPs. The effect of thickness on SMP’s response time was examined via both experiment and finite element analysis using Ansys transient thermal simulation. A method was developed to accurately measure the response time in millisecond resolution. Temperature distribution and heat transfer in specimens during thermal activation were also simulated and discussed. Finally, a spiral square and an artificial flower consisting of a single SMP were designed and printed with appropriate thickness variation for the demonstration of a controlled multi-stage shape recovery. Experimental results indicated that smart structures printed using single material with controlled thickness parameters are able to achieve controlled shape recovery characteristics similar to those printed with multiple materials and uniform geometric thickness. Hence, the geometric parameter can be used to increase the degree of freedom in designing future smart structures possessing complex shape recovery characteristics.

Printing-based fabrication method using sacrificial paper substrates for flexible and wearable microfluidic devices

NASA Astrophysics Data System (ADS)

Chung, Daehan; Gray, Bonnie L.

2017-11-01

We present a simple, fast, and inexpensive new printing-based fabrication process for flexible and wearable microfluidic channels and devices. Microfluidic devices are fabricated on textiles (fabric) for applications in clothing-based wearable microfluidic sensors and systems. The wearable and flexible microfluidic devices are comprised of water-insoluable screen-printable plastisol polymer. Sheets of paper are used as sacrificial substrates for multiple layers of polymer on the fabric’s surface. Microfluidic devices can be made within a short time using simple processes and inexpensive equipment that includes a laser cutter and a thermal laminator. The fabrication process is characterized to demonstrate control of microfluidic channel thickness and width. Film thickness smaller than 100 micrometers and lateral dimensions smaller than 150 micrometers are demonstrated. A flexible microfluidic mixer is also developed on fabric and successfully tested on both flat and curved surfaces at volumetric flow rates ranging from 5.5-46 ml min-1.

Ultra-thin flexible GaAs photovoltaics in vertical forms printed on metal surfaces without interlayer adhesives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Juho; Song, Kwangsun; Kim, Namyun

2016-06-20

Wearable flexible electronics often require sustainable power sources that are also mechanically flexible to survive the extreme bending that accompanies their general use. In general, thinner microelectronic devices are under less strain when bent. This paper describes strategies to realize ultra-thin GaAs photovoltaics through the interlayer adhesiveless transfer-printing of vertical-type devices onto metal surfaces. The vertical-type GaAs photovoltaic devices recycle reflected photons by means of bottom electrodes. Systematic studies with four different types of solar microcells indicate that the vertical-type solar microcells, at only a quarter of the thickness of similarly designed lateral-type cells, generate a level of electric powermore » similar to that of thicker cells. The experimental results along with the theoretical analysis conducted here show that the ultra-thin vertical-type solar microcells are durable under extreme bending and thus suitable for use in the manufacturing of wearable flexible electronics.« less

3D Printed Silicones with Shape Memory

DOE PAGES

Wu, Amanda S.; Small IV, Ward; Bryson, Taylor M.; ...

2017-07-05

Direct ink writing enables the layer-by-layer manufacture of ordered, porous structures whose mechanical behavior is driven by architecture and material properties. Here, we incorporate two different gas filled microsphere pore formers to evaluate the effect of shell stiffness and T g on compressive behavior and compression set in siloxane matrix printed structures. The lower T g microsphere structures exhibit substantial compression set when heated near and above T g, with full structural recovery upon reheating without constraint. By contrast, the higher T g microsphere structures exhibit reduced compression set with no recovery upon reheating. Aside from their role in tuningmore » the mechanical behavior of direct ink write structures, polymer microspheres are good candidates for shape memory elastomers requiring structural complexity, with potential applications toward tandem shape memory polymers.« less

3D Printed Silicones with Shape Memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Amanda S.; Small IV, Ward; Bryson, Taylor M.

Direct ink writing enables the layer-by-layer manufacture of ordered, porous structures whose mechanical behavior is driven by architecture and material properties. Here, we incorporate two different gas filled microsphere pore formers to evaluate the effect of shell stiffness and T g on compressive behavior and compression set in siloxane matrix printed structures. The lower T g microsphere structures exhibit substantial compression set when heated near and above T g, with full structural recovery upon reheating without constraint. By contrast, the higher T g microsphere structures exhibit reduced compression set with no recovery upon reheating. Aside from their role in tuningmore » the mechanical behavior of direct ink write structures, polymer microspheres are good candidates for shape memory elastomers requiring structural complexity, with potential applications toward tandem shape memory polymers.« less

Functionalized Graphitic Carbon Nitride for Metal-free, Flexible and Rewritable Nonvolatile Memory Device via Direct Laser-Writing

NASA Astrophysics Data System (ADS)

Zhao, Fei; Cheng, Huhu; Hu, Yue; Song, Long; Zhang, Zhipan; Jiang, Lan; Qu, Liangti

2014-07-01

Graphitic carbon nitride nanosheet (g-C3N4-NS) has layered structure similar with graphene nanosheet and presents unusual physicochemical properties due to the s-triazine fragments. But their electronic and electrochemical applications are limited by the relatively poor conductivity. The current work provides the first example that atomically thick g-C3N4-NSs are the ideal candidate as the active insulator layer with tunable conductivity for achieving the high performance memory devices with electrical bistability. Unlike in conventional memory diodes, the g-C3N4-NSs based devices combined with graphene layer electrodes are flexible, metal-free and low cost. The functionalized g-C3N4-NSs exhibit desirable dispersibility and dielectricity which support the all-solution fabrication and high performance of the memory diodes. Moreover, the flexible memory diodes are conveniently fabricated through the fast laser writing process on graphene oxide/g-C3N4-NSs/graphene oxide thin film. The obtained devices not only have the nonvolatile electrical bistability with great retention and endurance, but also show the rewritable memory effect with a reliable ON/OFF ratio of up to 105, which is the highest among all the metal-free flexible memory diodes reported so far, and even higher than those of metal-containing devices.

Mechanisms of resistance change under pressure for AgNP-based conducting wires

NASA Astrophysics Data System (ADS)

Qian, Zhentao; Liu, Liping; Huang, Han; Cheng, Xiong; Zhu, Xiaobo; Gu, Wenhua

2018-02-01

The silver nanoparticle (AgNP) based conducting wire is a fundamental element of flexible electronic devices, especially in the printing electronics area. Its resistance change mechanisms under pressure is of both scientific interest and practical importance. AgNP-based conducting wires were fabricated on flexible substrates by electrospraying printing technology, and three possible resistance change mechanisms were studied: vertical deformation (VD) of the AgNP wire due to vertical pressure, horizontal wire elongation (HWE) along with the flexible substrate due to vertical pressure, and local micro deformation (LMD) at the touching edge. Analysis of the experiment data revealed that the resistance change due to VD was negligible, the resistance change due to PWE was one order of magnitude smaller than the measured value, and the resistance change due to PWE was the dominating mechanism.

Mice Overexpressing Type 1 Adenylyl Cyclase Show Enhanced Spatial Memory Flexibility in the Absence of Intact Synaptic Long-Term Depression

ERIC Educational Resources Information Center

Zhang, Ming; Wang, Hongbing

2013-01-01

There is significant interest in understanding the contribution of intracellular signaling and synaptic substrates to memory flexibility, which involves new learning and suppression of obsolete memory. Here, we report that enhancement of Ca[superscript 2+]-stimulated cAMP signaling by overexpressing type 1 adenylyl cyclase (AC1) facilitated…

Flexibility of Event Boundaries in Autobiographical Memory

PubMed Central

Hohman, Timothy J.; Peynircioğlu, Zehra F.; Beason-Held, Lori L.

2014-01-01

Events have clear and consistent boundaries that are defined during perception in a manner that influences memory performance. The natural process of event segmentation shapes event definitions during perception, and appears to play a critical role in defining distinct episodic memories at encoding. However, the role of retrieval processes in modifying event definitions is not clear. We explored how such processes changed event boundary definitions at recall. In Experiment 1 we showed that distance from encoding is related to boundary flexibility. Participants were more likely to move self-reported event boundaries to include information reported beyond those boundaries when recalling more distant events compared to more recent events. In Experiment 2, we showed that age also influenced boundary flexibility. Older Age adults were more likely to move event boundaries than College Age adults, and the relationship between distance from encoding and boundary flexibility seen in Experiment 1 was present only in College Age and Middle Age adults. These results suggest that factors at retrieval have a direct impact on event definitions in memory and that, although episodic memories may be initially defined at encoding, these definitions are not necessarily maintained in long-term memory. PMID:22989194

Housing And Mounting Structure

DOEpatents

Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R.F.; Bryan, Robert P.; Carson, Richard F.; Duckett, III, Edwin B.; McCormick, Frederick B.; Miller, Gregory V.; Peterson, David W.; Smith, Terrance T.

2005-03-08

This invention relates to an optical transmitter, receiver or transceiver module, and more particularly, to an apparatus for connecting a first optical connector to a second optical connector. The apparatus comprises: (1) a housing having at least a first end and at least a second end, the first end of the housing capable of receiving the first optical connector, and the second end of the housing capable of receiving the second optical connector; (2) a longitudinal cavity extending from the first end of the housing to the second end of the housing; and (3) an electromagnetic shield comprising at least a portion of the housing. This invention also relates to an apparatus for housing a flexible printed circuit board, and this apparatus comprises: (1) a mounting structure having at least a first surface and a second surface; (2) alignment ridges along the first and second surfaces of the mounting structure, the alignment ridges functioning to align and secure a flexible printed circuit board that is wrapped around and attached to the first and second surfaces of the mounting structure; and (3) a series of heat sink ridges adapted to the mounting structure, the heat sink ridges functioning to dissipate heat that is generated from the flexible printed circuit board.

Formation of Au nano-patterns on various substrates using simplified nano-transfer printing method

NASA Astrophysics Data System (ADS)

Kim, Jong-Woo; Yang, Ki-Yeon; Hong, Sung-Hoon; Lee, Heon

2008-06-01

For future device applications, fabrication of the metal nano-patterns on various substrates, such as Si wafer, non-planar glass lens and flexible plastic films become important. Among various nano-patterning technologies, nano-transfer print method is one of the simplest techniques to fabricate metal nano-patterns. In nano-transfer printing process, thin Au layer is deposited on flexible PDMS mold, containing surface protrusion patterns, and the Au layer is transferred from PDMS mold to various substrates due to the difference of bonding strength of Au layer to PDMS mold and to the substrate. For effective transfer of Au layer, self-assembled monolayer, which has strong bonding to Au, is deposited on the substrate as a glue layer. In this study, complicated SAM layer coating process was replaced to simple UV/ozone treatment, which can activates the surface and form the -OH radicals. Using simple UV/ozone treatments on both Au and substrate, Au nano-pattern can be successfully transferred to as large as 6 in. diameter Si wafer, without SAM coating process. High fidelity transfer of Au nano-patterns to non-planar glass lens and flexible PET film was also demonstrated.

Photoconductive ZnO Films Printed on Flexible Substrates by Inkjet and Aerosol Jet Techniques

NASA Astrophysics Data System (ADS)

Winarski, D. J.; Kreit, E.; Heckman, E. M.; Flesburg, E.; Haseman, M.; Aga, R. S.; Selim, F. A.

2018-02-01

Zinc oxide (ZnO) thin films have remarkable versatility in sensor applications. Here, we report simple ink synthesis and printing methods to deposit ZnO photodetectors on a variety of flexible and transparent substrates, including polyimide (Kapton), polyethylene terephthalate, cyclic olefin copolymer (TOPAS), and quartz. X-ray diffraction analysis revealed the dependence of the film orientation on the substrate type and sintering method, and ultraviolet-visible (UV-Vis) absorption measurements revealed a band edge near 380 nm. van der Pauw technique was used to measure the resistivity of undoped ZnO and indium/gallium-codoped ZnO (IGZO) films. IGZO films showed lower resistivity and larger average grain size compared with undoped ZnO films due to addition of In3+ and Ga3+, which act as donors. A 365-nm light-emitting diode was used to photoirradiate the films to study their photoconductive response as a function of light intensity at 300 K. The results revealed that ZnO films printed by aerosol jet and inkjet techniques exhibited five orders of magnitude photoconductivity, indicating that such films are viable options for use in flexible photodetectors.

ABS 3D printed solutions for cryogenic applications

NASA Astrophysics Data System (ADS)

Bartolomé, E.; Bozzo, B.; Sevilla, P.; Martínez-Pasarell, O.; Puig, T.; Granados, X.

2017-03-01

3D printing has become a common, inexpensive and rapid prototyping technique, enabling the ad hoc fabrication of complex shapes. In this paper, we demonstrate that 3D printed objects in ABS can be used at cryogenic temperatures, offering flexible solutions in different fields. Firstly, a thermo-mechanical characterization of ABS 3D printed specimens at 77 K is reported, which allowed us to delimit the type of cryogenic uses where 3D printed pieces may be implemented. Secondly, we present three different examples where ABS 3D printed objects working at low temperatures have provided specific solutions: (i) SQUID inserts for angular magnetometry (low temperature material characterization field); (ii) a cage support for a metamaterial ;magnetic concentrator; (superconductivity application), and (iii) dedicated tools for cryopreservation in assisted reproductive techniques (medicine field).

Three-dimensional bioprinting of rat embryonic neural cells.

PubMed

Lee, Wonhye; Pinckney, Jason; Lee, Vivian; Lee, Jong-Hwan; Fischer, Krisztina; Polio, Samuel; Park, Je-Kyun; Yoo, Seung-Schik

2009-05-27

We present a direct cell printing technique to pattern neural cells in a three-dimensional (3D) multilayered collagen gel. A layer of collagen precursor was printed to provide a scaffold for the cells, and the rat embryonic neurons and astrocytes were subsequently printed on the layer. A solution of sodium bicarbonate was applied to the cell containing collagen layer as nebulized aerosols, which allowed the gelation of the collagen. This process was repeated layer-by-layer to construct the 3D cell-hydrogel composites. Upon characterizing the relationship between printing resolutions and the growth of printed neural cells, single/multiple layers of neural cell-hydrogel composites were constructed and cultured. The on-demand capability to print neural cells in a multilayered hydrogel scaffold offers flexibility in generating artificial 3D neural tissue composites.

Future opportunities for advancing glucose test device electronics.

PubMed

Young, Brian R; Young, Teresa L; Joyce, Margaret K; Kennedy, Spencer I; Atashbar, Massood Z

2011-09-01

Advancements in the field of printed electronics can be applied to the field of diabetes testing. A brief history and some new developments in printed electronics components applicable to personal test devices, including circuitry, batteries, transmission devices, displays, and sensors, are presented. Low-cost, thin, and lightweight materials containing printed circuits with energy storage or harvest capability and reactive/display centers, made using new printing/imaging technologies, are ideal for incorporation into personal-use medical devices such as glucose test meters. Semicontinuous rotogravure printing, which utilizes flexible substrates and polymeric, metallic, and/or nano "ink" composite materials to effect rapidly produced, lower-cost printed electronics, is showing promise. Continuing research advancing substrate, "ink," and continuous processing development presents the opportunity for research collaboration with medical device designers. © 2011 Diabetes Technology Society.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zwicker, Andrew P.; Bloom, Josh; Albertson, Robert

3D printing has become popular for a variety of users, from industrial to the home hobbyist, to scientists and engineers interested in producing their own laboratory equipment. In order to determine the suitability of 3D printed parts for our plasma physics laboratory, we measured the accuracy, strength, vacuum compatibility, and electrical properties of pieces printed in plastic. The flexibility of rapidly creating custom parts has led to the 3D printer becoming an invaluable resource in our laboratory and is equally suitable for producing equipment for advanced undergraduate laboratories.

Three-Dimensional Printing of Surgical Clips: An In Vitro Pilot Study and Trial of Efficacy.

PubMed

Canvasser, Noah E; De, Shuvro; Koseoglu, Ersin; Lay, Aaron H; Sorokin, Igor; Fernandez, Raul; Cadeddu, Jeffrey A

2017-09-01

Three-dimensional (3D) printing applications have increased over the past decade. Our objective was to test rapid prototyping of a 3D printed surgical clip for intraoperative use. Our prototype was modeled after the 10 mm Weck ® Hem-o-lok ® polymer clip (Teleflex, Inc., Wayne, PA). A 3D computer-aided design model of the Hem-o-lok clip was reverse engineered using commercial microscopy and printing was done using an Objet Connex500 multijetting system (Stratasys, Eden Prairie, MN). The initial polymer was Objet VeroWhitePlus RGD835; the addition of Objet TangoBlackPlus FLX980 during the design process improved hinge flexibility. The 3D printed clips were then pressure tested on rubber Penrose tubing and compared in vitro versus commercial Hem-o-lok clips. Initial 3D printed clips were not functional as they split at the hinge upon closure of the clip jaws. Design changes were made to add Objet TangoBlackPlus FLX980 at the hinge to improve flexibility. Additional modifications were made to allow for clips to be compatible with the Hem-o-lok endoscopic clip applier. A total of 50 clips were tested. Fracture rate for the printed clips using a clip applier was 54% (n = 27), whereas none of the commercial Hem-o-lok clips broke upon closure. Of the 23 printed clips that closed, mean leak was at 20.7 κPa (range 4.8-42.7). In contrast, none of the commercial clips leaked, and fill continued until Penrose rupture at mean 46.2 κPa (44.8-47.6). This pilot study demonstrates feasibility of 3D printing functional surgical clips. However, the performance of our first generation clips is poor compared with commercial grade product. Refinement in printers and materials available may allow for customization of such printed surgical instruments that could be economically competitive to purchasing and stocking product.

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghoneim, M. T.; Hussain, M. M., E-mail: muhammadmustafa.hussain@kaust.edu.sa

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ∼260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygenmore » and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.« less

Review of Batteryless Wireless Sensors Using Additively Manufactured Microwave Resonators.

PubMed

Memon, Muhammad Usman; Lim, Sungjoon

2017-09-09

The significant improvements observed in the field of bulk-production of printed microchip technologies in the past decade have allowed the fabrication of microchip printing on numerous materials including organic and flexible substrates. Printed sensors and electronics are of significant interest owing to the fast and low-cost fabrication techniques used in their fabrication. The increasing amount of research and deployment of specially printed electronic sensors in a number of applications demonstrates the immense attention paid by researchers to this topic in the pursuit of achieving wider-scale electronics on different dielectric materials. Although there are many traditional methods for fabricating radio frequency (RF) components, they are time-consuming, expensive, complicated, and require more power for operation than additive fabrication methods. This paper serves as a summary/review of improvements made to the additive printing technologies. The article focuses on three recently developed printing methods for the fabrication of wireless sensors operating at microwave frequencies. The fabrication methods discussed include inkjet printing, three-dimensional (3D) printing, and screen printing.

Review of Batteryless Wireless Sensors Using Additively Manufactured Microwave Resonators

PubMed Central

2017-01-01

The significant improvements observed in the field of bulk-production of printed microchip technologies in the past decade have allowed the fabrication of microchip printing on numerous materials including organic and flexible substrates. Printed sensors and electronics are of significant interest owing to the fast and low-cost fabrication techniques used in their fabrication. The increasing amount of research and deployment of specially printed electronic sensors in a number of applications demonstrates the immense attention paid by researchers to this topic in the pursuit of achieving wider-scale electronics on different dielectric materials. Although there are many traditional methods for fabricating radio frequency (RF) components, they are time-consuming, expensive, complicated, and require more power for operation than additive fabrication methods. This paper serves as a summary/review of improvements made to the additive printing technologies. The article focuses on three recently developed printing methods for the fabrication of wireless sensors operating at microwave frequencies. The fabrication methods discussed include inkjet printing, three-dimensional (3D) printing, and screen printing. PMID:28891947

Sleep On It: How Snoozing Strengthens Memories

MedlinePlus

... part of the U.S. Department of Health and Human Services Search form Search Site Menu Home Latest Issue Past Issues Special Issues Subscribe April 2013 Print this issue Sleep On It How Snoozing Strengthens Memories Send us your comments When you learn something ...

Cognitive remediation therapy (CRT) benefits more to patients with schizophrenia with low initial memory performances.

PubMed

Pillet, Benoit; Morvan, Yannick; Todd, Aurelia; Franck, Nicolas; Duboc, Chloé; Grosz, Aimé; Launay, Corinne; Demily, Caroline; Gaillard, Raphaël; Krebs, Marie-Odile; Amado, Isabelle

2015-01-01

Cognitive deficits in schizophrenia mainly affect memory, attention and executive functions. Cognitive remediation is a technique derived from neuropsychology, which aims to improve or compensate for these deficits. Working memory, verbal learning, and executive functions are crucial factors for functional outcome. Our purpose was to assess the impact of the cognitive remediation therapy (CRT) program on cognitive difficulties in patients with schizophrenia, especially on working memory, verbal memory, and cognitive flexibility. We collected data from clinical and neuropsychological assessments in 24 patients suffering from schizophrenia (Diagnostic and Statistical Manual of mental Disorders-Fourth Edition, DSM-IV) who followed a 3-month (CRT) program. Verbal and visuo-spatial working memory, verbal memory, and cognitive flexibility were assessed before and after CRT. The Wilcoxon test showed significant improvements on the backward digit span, on the visual working memory span, on verbal memory and on flexibility. Cognitive improvement was substantial when baseline performance was low, independently from clinical benefit. CRT is effective on crucial cognitive domains and provides a huge benefit for patients having low baseline performance. Such cognitive amelioration appears highly promising for improving the outcome in cognitively impaired patients.

Transferable and flexible label-like macromolecular memory on arbitrary substrates with high performance and a facile methodology.

PubMed

Lai, Ying-Chih; Hsu, Fang-Chi; Chen, Jian-Yu; He, Jr-Hau; Chang, Ting-Chang; Hsieh, Ya-Ping; Lin, Tai-Yuan; Yang, Ying-Jay; Chen, Yang-Fang

2013-05-21

A newly designed transferable and flexible label-like organic memory based on a graphene electrode behaves like a sticker, and can be readily placed on desired substrates or devices for diversified purposes. The memory label reveals excellent performance despite its physical presentation. This may greatly extend the memory applications in various advanced electronics and provide a simple scheme to integrate with other electronics. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

All-printed capacitors with continuous solution dispensing technology

NASA Astrophysics Data System (ADS)

Ge, Yang; Plötner, Matthias; Berndt, Andreas; Kumar, Amit; Voit, Brigitte; Pospiech, Doris; Fischer, Wolf-Joachim

2017-09-01

Printed electronics have been introduced into the commercial markets in recent years. Various printing technologies have emerged aiming to process printed electronic devices with low cost, environmental friendliness, and compatibility with large areas and flexible substrates. The aim of this study is to propose a continuous solution dispensing technology for processing all-printed thin-film capacitors on glass substrates using a leading-edge printing instrument. Among all printing technologies, this study provides concrete proof of the following outstanding advantages of this technology: high tolerance to inks, high throughput, low cost, and precise pattern transfers. Ag nanoparticle ink based on glycol ethers was used to print the electrodes. To obtain dielectric ink, a copolymer powder of poly(methyl methacrylate-co-benzoylphenyl methacrylate) containing crosslinkable side groups was dissolved in anisole. Various layouts were designed to support multiple electronic applications. Scanning electron microscopy and atomic force microscopy were used to investigate the all-printed capacitor layers formed using the proposed process. Additionally, the printed capacitors were electrically characterized under direct current and alternating current. The measured electrical properties of the printed capacitors were consistent with the theoretical results.

Printing polymer optical waveguides on conditioned transparent flexible foils by using the aerosol jet technology

NASA Astrophysics Data System (ADS)

Reitberger, Thomas; Hoffmann, Gerd-Albert; Wolfer, Tim; Overmeyer, Ludger; Franke, Joerg

2016-09-01

The optical data transfer is considered as the future of signal transfer due to its various advantages compared to conventional copper-based technologies. The Aerosol Jet Printing (AJP) technology offers the opportunity to print materials with high viscosities, such as liquid transparent polymer adhesives (epoxy resins), on almost any possible substrate material and even in third dimension. This paper introduces a new flexible and comparatively cost-effective way of generating polymer optical waveguides through AJP. Furthermore, the conditioning of the substrate material and the printing process of planar waveguides are presented. In the first step, two lines with hydrophobic behavior are applied on foil material (PMMA, PVC, PI) by using a flexographic printing machine. These silicone based patterns containing functional polymer form barriers for the core material due to their low surface energy after curing. In the second step, the core material (liquid polymer, varnish) is printed between the barrier lines. Because of the hydrophobic behavior of the lines, the contact angle between the substrate surface and the liquid core material is increased which yields to higher aspect ratio. The distance between the barrier lines is at least 100 μm, which defines the width of the waveguide. The minimum height of the core shall be 50 μm. After UV-curing of the core polymer, the cladding material is printed on the top. This is also applied by using the AJP technology. Various tests were performed to achieve the optimal surface properties for adequate adhesion and machine process parameters.

All-printed, flexible, reconfigurable frequency selective surfaces

NASA Astrophysics Data System (ADS)

Haghzadeh, Mahdi; Akyurtlu, Alkim

2016-11-01

We demonstrate a new fully printed, conformal, band-pass frequency selective surface (FSS) utilizing a novel interdigitated capacitor (IDC), in which the space between the fingers can be filled with dielectric materials with different dielectric constants. Every dielectric constant corresponds to a different resonance frequency for the FSS, leading to a bandpass performance that can be tuned in a static manner based on the dielectric choice. The 2-D FSS consists of a periodic array of non-resonant and subwavelength structures (i.e., a metallic square loop and a wire grid) printed on either side of a flexible polyimide film using direct-ink writing methodologies. The miniaturized-element nature of this metamaterial-inspired FSS results in localized frequency-selective properties with very low sensitivity to the angle of incidence. Moreover, its symmetric design makes it polarization independent. A multiphase barium strontium titanate/cyclic olefin copolymer (BST/COC) composite with two different BST loadings, corresponding to two different dielectric constants, is the dielectric ink that is printed on the IDCs to vary the resonance frequency of the FSS. Different models of the FSS involving various IDC designs, with a first-order bandpass response at X-band, were simulated, printed, and measured. The center frequency of the template FSS with the air-filled IDC was tuned by 4.52% and 21.08% from 9.96 GHz by printing BST/COC dielectrics with different BST loadings on the IDCs. Moreover, the operation mode of the FSS was switched from a first order filter to a dual-band filter using printed BST/COC ink in a novel FSS design.

Inkjet printing of single-crystal films.

PubMed

Minemawari, Hiromi; Yamada, Toshikazu; Matsui, Hiroyuki; Tsutsumi, Jun'ya; Haas, Simon; Chiba, Ryosuke; Kumai, Reiji; Hasegawa, Tatsuo

2011-07-13

The use of single crystals has been fundamental to the development of semiconductor microelectronics and solid-state science. Whether based on inorganic or organic materials, the devices that show the highest performance rely on single-crystal interfaces, with their nearly perfect translational symmetry and exceptionally high chemical purity. Attention has recently been focused on developing simple ways of producing electronic devices by means of printing technologies. 'Printed electronics' is being explored for the manufacture of large-area and flexible electronic devices by the patterned application of functional inks containing soluble or dispersed semiconducting materials. However, because of the strong self-organizing tendency of the deposited materials, the production of semiconducting thin films of high crystallinity (indispensable for realizing high carrier mobility) may be incompatible with conventional printing processes. Here we develop a method that combines the technique of antisolvent crystallization with inkjet printing to produce organic semiconducting thin films of high crystallinity. Specifically, we show that mixing fine droplets of an antisolvent and a solution of an active semiconducting component within a confined area on an amorphous substrate can trigger the controlled formation of exceptionally uniform single-crystal or polycrystalline thin films that grow at the liquid-air interfaces. Using this approach, we have printed single crystals of the organic semiconductor 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C(8)-BTBT) (ref. 15), yielding thin-film transistors with average carrier mobilities as high as 16.4 cm(2) V(-1) s(-1). This printing technique constitutes a major step towards the use of high-performance single-crystal semiconductor devices for large-area and flexible electronics applications.

3D Printing of Living Responsive Materials and Devices.

PubMed

Liu, Xinyue; Yuk, Hyunwoo; Lin, Shaoting; Parada, German Alberto; Tang, Tzu-Chieh; Tham, Eléonore; de la Fuente-Nunez, Cesar; Lu, Timothy K; Zhao, Xuanhe

2018-01-01

3D printing has been intensively explored to fabricate customized structures of responsive materials including hydrogels, liquid-crystal elastomers, shape-memory polymers, and aqueous droplets. Herein, a new method and material system capable of 3D-printing hydrogel inks with programed bacterial cells as responsive components into large-scale (3 cm), high-resolution (30 μm) living materials, where the cells can communicate and process signals in a programmable manner, are reported. The design of 3D-printed living materials is guided by quantitative models that account for the responses of programed cells in printed microstructures of hydrogels. Novel living devices are further demonstrated, enabled by 3D printing of programed cells, including logic gates, spatiotemporally responsive patterning, and wearable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Four-Dimensional Printing Hierarchy Scaffolds with Highly Biocompatible Smart Polymers for Tissue Engineering Applications.

PubMed

Miao, Shida; Zhu, Wei; Castro, Nathan J; Leng, Jinsong; Zhang, Lijie Grace

2016-10-01

The objective of this study was to four-dimensional (4D) print novel biomimetic gradient tissue scaffolds with highly biocompatible naturally derived smart polymers. The term "4D printing" refers to the inherent smart shape transformation of fabricated constructs when implanted minimally invasively for seamless and dynamic integration. For this purpose, a series of novel shape memory polymers with excellent biocompatibility and tunable shape changing effects were synthesized and cured in the presence of three-dimensional printed sacrificial molds, which were subsequently dissolved to create controllable and graded porosity within the scaffold. Surface morphology, thermal, mechanical, and biocompatible properties as well as shape memory effects of the synthesized smart polymers and resultant porous scaffolds were characterized. Fourier transform infrared spectroscopy and gel content analysis confirmed the formation of chemical crosslinking by reacting polycaprolactone triol and castor oil with multi-isocyanate groups. Differential scanning calorimetry revealed an adjustable glass transition temperature in a range from -8°C to 35°C. Uniaxial compression testing indicated that the obtained polymers, possessing a highly crosslinked interpenetrating polymeric networks, have similar compressive modulus to polycaprolactone. Shape memory tests revealed that the smart polymers display finely tunable recovery speed and exhibit greater than 92% shape fixing at -18°C or 0°C and full shape recovery at physiological temperature. Scanning electron microscopy analysis of fabricated scaffolds revealed a graded microporous structure, which mimics the nonuniform distribution of porosity found within natural tissues. With polycaprolactone serving as a control, human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and differentiation greatly increased on our novel smart polymers. The current work will significantly advance the future design and development of novel and functional biomedical scaffolds with advanced 4D printing technology and highly biocompatible smart biomaterials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.

The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

Functionalized Graphitic Carbon Nitride for Metal-free, Flexible and Rewritable Nonvolatile Memory Device via Direct Laser-Writing

PubMed Central

Zhao, Fei; Cheng, Huhu; Hu, Yue; Song, Long; Zhang, Zhipan; Jiang, Lan; Qu, Liangti

2014-01-01

Graphitic carbon nitride nanosheet (g-C3N4-NS) has layered structure similar with graphene nanosheet and presents unusual physicochemical properties due to the s-triazine fragments. But their electronic and electrochemical applications are limited by the relatively poor conductivity. The current work provides the first example that atomically thick g-C3N4-NSs are the ideal candidate as the active insulator layer with tunable conductivity for achieving the high performance memory devices with electrical bistability. Unlike in conventional memory diodes, the g-C3N4-NSs based devices combined with graphene layer electrodes are flexible, metal-free and low cost. The functionalized g-C3N4-NSs exhibit desirable dispersibility and dielectricity which support the all-solution fabrication and high performance of the memory diodes. Moreover, the flexible memory diodes are conveniently fabricated through the fast laser writing process on graphene oxide/g-C3N4-NSs/graphene oxide thin film. The obtained devices not only have the nonvolatile electrical bistability with great retention and endurance, but also show the rewritable memory effect with a reliable ON/OFF ratio of up to 105, which is the highest among all the metal-free flexible memory diodes reported so far, and even higher than those of metal-containing devices. PMID:25073687

Flexible and stackable terahertz metamaterials via silver-nanoparticle inkjet printing

NASA Astrophysics Data System (ADS)

Kashiwagi, K.; Xie, L.; Li, X.; Kageyama, T.; Miura, M.; Miyashita, H.; Kono, J.; Lee, S.-S.

2018-04-01

There is presently much interest in tunable, flexible, or reconfigurable metamaterial structures that work in the terahertz frequency range. They can be useful for a range of applications, including spectroscopy, sensing, imaging, and communications. Various methods based on microelectromechanical systems have been used for fabricating terahertz metamaterials, but they typically require high-cost facilities and involve a number of time-consuming and intricate processes. Here, we demonstrate a simple, robust, and cost-effective method for fabricating flexible and stackable multiresonant terahertz metamaterials, using silver nanoparticle inkjet printing. Using this method, we designed and fabricated two arrays of split-ring resonators (SRRs) having different resonant frequencies on separate sheets of paper and then combined the two arrays by stacking. Through terahertz time-domain spectroscopy, we observed resonances at the frequencies expected for the individual SRR arrays as well as at a new frequency due to coupling between the two SRR arrays.

High-Resolution and Frequency, Printed Miniature Magnetic Probes

NASA Astrophysics Data System (ADS)

Prager, James; Ziemba, Timothy; Miller, Kenneth; Picard, Julian

2013-10-01

Eagle Harbor Technologies, Inc. (EHT) is developing a technique to significantly reduce the cost and development time of producing magnetic field diagnostics. EHT is designing probes that can be printed on flexible PCBs thereby allowing for extremely small coils to be produced while essentially eliminating the time to wind the coils. The coil size can be extremely small when coupled with the EHT Hybrid Integrator, which is capable of high bandwidth measurements over short and long pulse durations. This integrator is currently being commercialized with the support of a DOE SBIR. Additionally, the flexible PCBs allow probes to be attached to complex surface and/or probes that have a complex 3D structure to be designed and fabricated. During the Phase I, EHT will design and construct magnetic field probes on flexible PCBs, which will be tested at the University of Washington's HIT-SI experiment and in EHT's material science plasma reactor. Funding provided by DOE SBIR/STTR Program.

Optical properties of flexible fluorescent films prepared by screen printing technology

NASA Astrophysics Data System (ADS)

Chen, Yan; Ke, Taiyan; Chen, Shuijin; He, Xin; Zhang, Mei; Li, Dong; Deng, Jinfeng; Zeng, Qingguang

2018-05-01

In this work, we prepared a fluorescent film comprised phosphors and silicone on flexible polyethylene terephthalate (PET) substrate using a screen printing technology. The effects of mesh number and weight ratio of phosphors to silicone on the optical properties of the flexible films were investigated. The results indicate that the emission intensity of the film increase as the mesh decreased from 400 to 200, but the film surface gradually becomes uneven. The fluorescent film with high emission intensity and smooth surface can be obtained when the weight ratio of phosphor to gel is 2:1, and mesh number is 300. The luminous efficiency of the fabricated LEDs combined the fluorescent films with 460 nm Ga(In)N chip module can reach 75 lm/W. The investigation indicates that the approach can be applied in the remote fluorescent film conversion and decreases the requirements of the particle size and the dispersion state of fluorescent materials.

Optically transparent frequency selective surfaces on flexible thin plastic substrates

NASA Astrophysics Data System (ADS)

Dewani, Aliya A.; O'Keefe, Steven G.; Thiel, David V.; Galehdar, Amir

2015-02-01

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

Emergent Literacy Skills in Preschool Children With Hearing Loss Who Use Spoken Language: Initial Findings From the Early Language and Literacy Acquisition (ELLA) Study.

PubMed

Werfel, Krystal L

2017-10-05

The purpose of this study was to compare change in emergent literacy skills of preschool children with and without hearing loss over a 6-month period. Participants included 19 children with hearing loss and 14 children with normal hearing. Children with hearing loss used amplification and spoken language. Participants completed measures of oral language, phonological processing, and print knowledge twice at a 6-month interval. A series of repeated-measures analyses of variance were used to compare change across groups. Main effects of time were observed for all variables except phonological recoding. Main effects of group were observed for vocabulary, morphosyntax, phonological memory, and concepts of print. Interaction effects were observed for phonological awareness and concepts of print. Children with hearing loss performed more poorly than children with normal hearing on measures of oral language, phonological memory, and conceptual print knowledge. Two interaction effects were present. For phonological awareness and concepts of print, children with hearing loss demonstrated less positive change than children with normal hearing. Although children with hearing loss generally demonstrated a positive growth in emergent literacy skills, their initial performance was lower than that of children with normal hearing, and rates of change were not sufficient to catch up to the peers over time.

Fingerspelled and Printed Words Are Recoded into a Speech-based Code in Short-term Memory.

PubMed

Sehyr, Zed Sevcikova; Petrich, Jennifer; Emmorey, Karen

2017-01-01

We conducted three immediate serial recall experiments that manipulated type of stimulus presentation (printed or fingerspelled words) and word similarity (speech-based or manual). Matched deaf American Sign Language signers and hearing non-signers participated (mean reading age = 14-15 years). Speech-based similarity effects were found for both stimulus types indicating that deaf signers recoded both printed and fingerspelled words into a speech-based phonological code. A manual similarity effect was not observed for printed words indicating that print was not recoded into fingerspelling (FS). A manual similarity effect was observed for fingerspelled words when similarity was based on joint angles rather than on handshape compactness. However, a follow-up experiment suggested that the manual similarity effect was due to perceptual confusion at encoding. Overall, these findings suggest that FS is strongly linked to English phonology for deaf adult signers who are relatively skilled readers. This link between fingerspelled words and English phonology allows for the use of a more efficient speech-based code for retaining fingerspelled words in short-term memory and may strengthen the representation of English vocabulary. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Shape-morphing composites with designed micro-architectures

NASA Astrophysics Data System (ADS)

Rodriguez, Jennifer N.; Zhu, Cheng; Duoss, Eric B.; Wilson, Thomas S.; Spadaccini, Christopher M.; Lewicki, James P.

2016-06-01

Shape memory polymers (SMPs) are attractive materials due to their unique mechanical properties, including high deformation capacity and shape recovery. SMPs are easier to process, lightweight, and inexpensive compared to their metallic counterparts, shape memory alloys. However, SMPs are limited to relatively small form factors due to their low recovery stresses. Lightweight, micro-architected composite SMPs may overcome these size limitations and offer the ability to combine functional properties (e.g., electrical conductivity) with shape memory behavior. Fabrication of 3D SMP thermoset structures via traditional manufacturing methods is challenging, especially for designs that are composed of multiple materials within porous microarchitectures designed for specific shape change strategies, e.g. sequential shape recovery. We report thermoset SMP composite inks containing some materials from renewable resources that can be 3D printed into complex, multi-material architectures that exhibit programmable shape changes with temperature and time. Through addition of fiber-based fillers, we demonstrate printing of electrically conductive SMPs where multiple shape states may induce functional changes in a device and that shape changes can be actuated via heating of printed composites. The ability of SMPs to recover their original shapes will be advantageous for a broad range of applications, including medical, aerospace, and robotic devices.

3D-Printing: an emerging and a revolutionary technology in pharmaceuticals.

PubMed

Singhvi, Gautam; Patil, Shalini; Girdhar, Vishal; Chellappan, Dinesh K; Gupta, Gaurav; Dua, Kamal

2018-06-01

One of the novel and progressive technology employed in pharmaceutical manufacturing, design of medical device and tissue engineering is threedimensional (3D) printing. 3D printing technologies provide great advantages in 3D scaffolds fabrication over traditional methods in the control of pore size, porosity, and interconnectivity. Various techniques of 3Dprinting include powder bed fusion, fused deposition modeling, binder deposition, inkjet printing, photopolymerization and many others which are still evolving. 3Dprinting technique been employed in developing immediate release products, various systems to deliver multiple release modalities etc. 3D printing has opened the door for new generation of customized drug delivery with builtin flexibility for safer and effective therapy. Our minireview provides a quick snapshot on an overview of 3D printing, various techniques employed, applications and its advancements in pharmaceutical sciences.

Hard and flexible optical printed circuit board

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-02-01

We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

Advanced Mail Systems Scanner Technology. Executive Summary and Appendixes A-E.

DTIC Science & Technology

1980-10-01

data base. 6. Perform color acquisition studies. 7. Investigate address and bar code reading. MASS MEMORY TECHNOLOGY 1. Collect performance data on...area of the 1728-by-2200 ICAS image memory and to transmit the data to any of the three color memories of the Comtal. Function table information can...for printing color images. The software allows the transmission of data from the ICAS frame-store memory via the MCU to the Dicomed. Software test

Fully Packaged Carbon Nanotube Supercapacitors by Direct Ink Writing on Flexible Substrates.

PubMed

Chen, Bolin; Jiang, Yizhou; Tang, Xiaohui; Pan, Yayue; Hu, Shan

2017-08-30

The ability to print fully packaged integrated energy storage components (e.g., supercapacitors) is of critical importance for practical applications of printed electronics. Due to the limited variety of printable materials, most studies on printed supercapacitors focus on printing the electrode materials but rarely the full-packaged cell. This work presents for the first time the printing of a fully packaged single-wall carbon nanotube-based supercapacitor with direct ink writing (DIW) technology. Enabled by the developed ink formula, DIW setup, and cell architecture, the whole printing process is mask free, transfer free, and alignment free with precise and repeatable control on the spatial distribution of all constituent materials. Studies on cell design show that a wider electrode pattern and narrower gap distance between electrodes lead to higher specific capacitance. The as-printed fully packaged supercapacitors have energy and power performances that are among the best in recently reported planar carbon-based supercapacitors that are only partially printed or nonprinted.

Dreams Memories & Photography

ERIC Educational Resources Information Center

Young, Bernard

2012-01-01

Photography students spend a considerable amount of time working on technical issues in shooting, composing, editing, and processing prints. Another aspect of their learning should include the conception and communication of their ideas. A student's memories and dreams can serve as motivation to create images in visual art. Some artists claim that…

Interference Effects on the Recall of Pictures, Printed Words and Spoken Words.

ERIC Educational Resources Information Center

Burton, John K.; Bruning, Roger H.

Thirty college undergraduates participated in a study of the effects of acoustic and visual interference on the recall of word and picture triads in both short-term and long-term memory. The subjects were presented 24 triads of monosyllabic nouns representing all of the possible combinations of presentation types: pictures, printed words, and…

Sorting of large-diameter semiconducting carbon nanotube and printed flexible driving circuit for organic light emitting diode (OLED).

PubMed

Xu, Wenya; Zhao, Jianwen; Qian, Long; Han, Xianying; Wu, Liangzhuan; Wu, Weichen; Song, Minshun; Zhou, Lu; Su, Wenming; Wang, Chao; Nie, Shuhong; Cui, Zheng

2014-01-01

A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10(-3) A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 10(4) and output current up to 3.5 × 10(-4) A at V(scan) = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications.

Current use and potential of additive manufacturing for optical applications

NASA Astrophysics Data System (ADS)

Brunelle, Matthew; Ferralli, Ian; Whitsitt, Rebecca; Medicus, Kate

2017-10-01

Additive manufacturing, or 3D printing, has become widely used in recent years for the creation of both prototype and end-use parts. Because the parts are created in a layer-by-layer manner, the flexibility of additive manufacturing is unparalleled and has opened the design space to enable features like undercuts and internal channels which cannot exist on traditional, subtractively manufactured parts. This flexibility can also be leveraged for optical applications. This paper outlines some of the current uses of 3D printing in the optical manufacturing process at Optimax. Several materials and additive technologies are utilized, including polymer printing through fused deposition modeling, which creates parts by depositing a softened thermoplastic filament in a layerwise fashion. Stereolithography, which uses light to cure layers of a photopolymer resin, will also be discussed. These technologies are used to manufacture functional prototypes, fixtures, sealed housings, and other components. Additionally, metal printing through selective laser melting, which uses a laser to melt metal powder layers into a dense solid, will be discussed due to the potential to manufacture thermally stable opticalmechanical assembly frameworks and functional optics. Examples of several additively manufactured optical components will be shown.

Biometrics and smart cards combine to offer high security

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seidman, S.

1986-01-01

This paper discusses the Smart Card a plastic credit card sized package with an embedded computer chip which encompasses a level of technical sophistication which makes it virtually impossible to counterfeit. The question of legitimacy of the person using the Card for physical, computer, or network access can be answered by storing a biometric template of the authorized user in the Smart Card's unalterable memory. The bimetric template can be based upon a retina print, a hand print, a finger print, a wrist-vein print, a voice print, or pseudo-biometrics, such as signature dynamics, gait dynamics or keyboard typing patterns. Thesemore » Cards will function only when they are being used by the authorized individuals to whom they are issued.« less

Laser printed plasmonic color metasurfaces (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kristensen, Anders; Zhu, Xiaolong; Højlund-Nielsen, Emil; Vannahme, Christoph; Mortensen, N. Asger

2016-09-01

This paper describes color printing on nanoimprinted plasmonic metasurfaces by laser post-writing, for flexible decoration of high volume manufactured plastic products. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Different surface morphologies that support different plasmonic resonances, and thereby different color appearances, are created by control of the laser pulse energy density. All primary colors can be printed, with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel.

Manufacturing of polylactic acid nanocomposite 3D printer filaments for smart textile applications

NASA Astrophysics Data System (ADS)

Hashemi Sanatgar, R.; Cayla, A.; Campagne, C.; Nierstrasz, V.

2017-10-01

In this paper, manufacturing of polylactic acid nanocomposite 3D printer filaments was considered for smart textile applications. 3D printing process was applied as a novel process for deposition of nanocomposites on PLA fabrics to introduce more flexible, resourceefficient and cost effective textile functionalization processes than conventional printing process like screen and inkjet printing. The aim is to develop an integrated or tailored production process for smart and functional textiles which avoid unnecessary use of water, energy, chemicals and minimize the waste to improve ecological footprint and productivity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glawe, Andrea; Eggerath, Daniel; Schäfer, Frank

The market of Large Area Organic Printed Electronics is developing rapidly to increase efficiency and quality as well as to lower costs further. Applications for OPV, OLED, RFID and compact Printed Electronic systems are increasing. In order to make the final products more affordable, but at the same time highly accurate, Roll to Roll (R2R) production on flexible transparent polymer substrates is the way forward. There are numerous printing and coating technologies suitable depending on the design, the product application and the chemical process technology. Mainly the product design (size, pattern, repeatability) defines the application technology.

High-Resolution Printing of 3D Structures Using an Electrohydrodynamic Inkjet with Multiple Functional Inks.

PubMed

An, Byeong Wan; Kim, Kukjoo; Lee, Heejoo; Kim, So-Yun; Shim, Yulhui; Lee, Dae-Young; Song, Jun Yeob; Park, Jang-Ung

2015-08-05

Electrohydrodynamic-inkjet-printed high-resolution complex 3D structures with multiple functional inks are demonstrated. Printed 3D structures can have a variety of fine patterns, such as vertical or helix-shaped pillars and straight or rounded walls, with high aspect ratios (greater than ≈50) and narrow diameters (≈0.7 μm). Furthermore, the formation of freestanding, bridge-like Ag wire structures on plastic substrates suggests substantial potentials as high-precision, flexible 3D interconnects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The development of cognitive flexibility beyond the preschool period: an investigation using a modified Flexible Item Selection Task.

PubMed

Dick, Anthony Steven

2014-09-01

We explored the development of cognitive flexibility in typically developing 6-, 8-, and 10-year-olds and adults by modifying a common cognitive flexibility task, the Flexible Item Selection Task (FIST). Although performance on the standard FIST reached ceiling by 8 years, FIST performance on other variations continued to improve until 10 years of age. Within a detailed task analysis, we also explored working memory storage and processing components of executive function and how these contribute to the development of cognitive flexibility. The findings reinforce the notion that cognitive flexibility is a multifaceted construct but that the development of working memory contributes in part to age-related change in this ability. Copyright © 2014 Elsevier Inc. All rights reserved.

Active Control of Flexible Space Structures Using the Nitinol Shape Memory Actuators

DTIC Science & Technology

1987-10-01

number) FIELD !GROUP SUBGROUP I Active Control, Nitinol Actuators, Space Structures 9. ABSTRACT (Continue on reverse if necessary and identify by block...number) Summarizes research progress in the feasibility demonstration of active vibration control using Nitinol shape memory actuators. Tests on...FLEXIBLE SPACE STRUCTURES USING NITINOL SHAPE MEMORY ACTUATORS FINAL REPORT FOR PHASE I SDIO CONTRACT #F49620-87-C-0035 0 BY DR. AMR M. BAZ KARIM R

Flexible hybrid circuit fully inkjet-printed: Surface mount devices assembled by silver nanoparticles-based inkjet ink

NASA Astrophysics Data System (ADS)

Arrese, J.; Vescio, G.; Xuriguera, E.; Medina-Rodriguez, B.; Cornet, A.; Cirera, A.

2017-03-01

Nowadays, inkjet-printed devices such as transistors are still unstable in air and have poor performances. Moreover, the present electronics applications require a high degree of reliability and quality of their properties. In order to accomplish these application requirements, hybrid electronics is fulfilled by combining the advantages of the printing technologies with the surface-mount technology. In this work, silver nanoparticle-based inkjet ink (AgNP ink) is used as a novel approach to connect surface-mount devices (SMDs) onto inkjet-printed pads, conducted by inkjet printing technology. Excellent quality AgNP ink-junctions are ensured with high resolution picoliter drop jetting at low temperature (˜150 °C). Electrical, mechanical, and morphological characterizations are carried out to assess the performance of the AgNP ink junction. Moreover, AgNP ink is compared with common benchmark materials (i.e., silver epoxy and solder). Electrical contact resistance characterization shows a similar performance between the AgNP ink and the usual ones. Mechanical characterization shows comparable shear strength for AgNP ink and silver epoxy, and both present higher adhesion than solder. Morphological inspections by field-emission scanning electron microscopy confirm a high quality interface of the silver nanoparticle interconnection. Finally, a flexible hybrid circuit on paper controlled by an Arduino board is manufactured, demonstrating the viability and scalability of the AgNP ink assembling technique.

Characterization and optimization of an inkjet-printed smart textile UV-sensor cured with UV-LED light

NASA Astrophysics Data System (ADS)

Seipel, S.; Yu, J.; Periyasamy, A. P.; Viková, M.; Vik, M.; Nierstrasz, V. A.

2017-10-01

For the development of niche products like smart textiles and other functional high-end products, resource-saving production processes are needed. Niche products only require small batches, which makes their production with traditional textile production techniques time-consuming and costly. To achieve a profitable production, as well as to further foster innovation, flexible and integrated production techniques are a requirement. Both digital inkjet printing and UV-light curing contribute to a flexible, resource-efficient, energy-saving and therewith economic production of smart textiles. In this article, a smart textile UV-sensor is printed using a piezoelectric drop-on-demand printhead and cured with a UV-LED lamp. The UVcurable ink system is based on free radical polymerization and the integrated UVsensing material is a photochromic dye, Reversacol Ruby Red. The combination of two photoactive compounds, for which UV-light is both the curer and the activator, challenges two processes: polymer crosslinking of the resin and color performance of the photochromic dye. Differential scanning calorimetry (DSC) is used to characterize the curing efficiency of the prints. Color measurements are made to determine the influence of degree of polymer crosslinking on the developed color intensities, as well as coloration and decoloration rates of the photochromic prints. Optimized functionality of the textile UV-sensor is found using different belt speeds and lamp intensities during the curing process.

4D printing of polymeric materials for tissue and organ regeneration.

PubMed

Miao, Shida; Castro, Nathan; Nowicki, Margaret; Xia, Lang; Cui, Haitao; Zhou, Xuan; Zhu, Wei; Lee, Se-Jun; Sarkar, Kausik; Vozzi, Giovanni; Tabata, Yasuhiko; Fisher, John; Zhang, Lijie Grace

2017-12-01

Four dimensional (4D) printing is an emerging technology with great capacity for fabricating complex, stimuli-responsive 3D structures, providing great potential for tissue and organ engineering applications. Although the 4D concept was first highlighted in 2013, extensive research has rapidly developed, along with more-in-depth understanding and assertions regarding the definition of 4D. In this review, we begin by establishing the criteria of 4D printing, followed by an extensive summary of state-of-the-art technological advances in the field. Both transformation-preprogrammed 4D printing and 4D printing of shape memory polymers are intensively surveyed. Afterwards we will explore and discuss the applications of 4D printing in tissue and organ regeneration, such as developing synthetic tissues and implantable scaffolds, as well as future perspectives and conclusions.

A comparative study of bio-inspired protective scales using 3D printing and mechanical testing.

PubMed

Martini, Roberto; Balit, Yanis; Barthelat, Francois

2017-06-01

Flexible natural armors from fish, alligators or armadillo are attracting an increasing amount of attention for their unique combinations of hardness, flexibility and light weight. The extreme contrast of stiffness between hard scales and surrounding soft tissues gives rise to unusual and attractive mechanisms, which now serve as models for the design of bio-inspired armors. Despite this growing interest, there is little guideline for the choice of materials, optimum thickness, size, shape and arrangement for the protective scales. In this work, we explore how the geometry and arrangement of hard scales can be tailored to promote scale-scale interactions. We use 3D printing to fabricate arrays of scales with increasingly complex geometries and arrangements, from simple squares with no overlap to complex ganoid-scales with overlaps and interlocking features. We performed puncture tests and flexural tests on each of the 3D printed materials, and we report the puncture resistance - compliance characteristics of each design on an Ashby chart. The interactions between the scales can significantly increase the resistance to puncture, and these interactions can be maximized by tuning the geometry and arrangement of the scales. Interestingly, the designs that offer the best combinations of puncture resistance and flexural compliance are similar to the geometry and arrangement of natural teleost and ganoid scales, which suggests that natural evolution has shaped these systems to maximize flexible protection. This study yields new insights into the mechanisms of natural dermal armor, and also suggests new designs for personal protective systems. Flexible natural armors from fishes, alligators or armadillos are attracting an increasing amount of attention for their unique and attractive combinations of hardness, flexibility and low weight. Despite a growing interest in bio-inspired flexible protection, there is still little guideline for the choice of materials, optimum thickness, size, shape and arrangement of the protective scales. In this work, we explore how the geometry and arrangement of hard scales affect puncture resistance and flexural compliance, using 3D printing and mechanical testing. Our main finding is that the performance of the scaled skin in terms of puncture resistance can be significantly improved by slight changes in their geometry and arrangement. Our results also suggest that natural evolution has shaped scaled skins to maximize flexible protection. This study yields new insights into the mechanics of natural dermal armors, and also suggests new designs for personal protective systems. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

3D Printed Wearable Sensors with Liquid Metals for the Pose Detection of Snakelike Soft Robots.

PubMed

Zhou, Luyu; Gao, Qing; Zhan, Jun-Fu; Xie, Chao-Qi; Fu, Jianzhong; He, Yong

2018-06-18

Liquid metal-based flexible sensors, which utilize advanced liquid conductive material to serve as sensitive element, is emerging as a promising solution to measure large deformations. Nowadays, one of the biggest challenges for precise control of soft robots is the detection of their real time positions. Existing fabrication methods are unable to fabricate flexible sensors that match the shape of soft robots. In this report, we firstly described a novel 3D printed multi-function inductance flexible and stretchable sensor with liquid metals (LMs), which is capable of measuring both axial tension and curvature. This sensor is fabricated with a developed coaxial liquid metal 3D printer by co-printing of silicone rubber and LMs. Due to the solenoid shape, this sensor can be easily installed on snakelike soft robots and can accurately distinguish different degrees of tensile and bending deformation. We determined the structural parameters of the sensor and proved its excellent stability and reliability. As a demonstration, we used this sensor to measure the curvature of a finger and feedback the position of endoscope, a typical snakelike structure. Because of its bending deformation form consistent with the actual working status of the soft robot and unique shape, this sensor has better practical application prospects in the pose detection.

Memory dynamics under stress.

PubMed

Quaedflieg, Conny W E M; Schwabe, Lars

2018-03-01

Stressful events have a major impact on memory. They modulate memory formation in a time-dependent manner, closely linked to the temporal profile of action of major stress mediators, in particular catecholamines and glucocorticoids. Shortly after stressor onset, rapidly acting catecholamines and fast, non-genomic glucocorticoid actions direct cognitive resources to the processing and consolidation of the ongoing threat. In parallel, control of memory is biased towards rather rigid systems, promoting habitual forms of memory allowing efficient processing under stress, at the expense of "cognitive" systems supporting memory flexibility and specificity. In this review, we discuss the implications of this shift in the balance of multiple memory systems for the dynamics of the memory trace. Specifically, stress appears to hinder the incorporation of contextual details into the memory trace, to impede the integration of new information into existing knowledge structures, to impair the flexible generalisation across past experiences, and to hamper the modification of memories in light of new information. Delayed, genomic glucocorticoid actions might reverse the control of memory, thus restoring homeostasis and "cognitive" control of memory again.

3D Printed Multimaterial Microfluidic Valve.

PubMed

Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

2016-01-01

We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.

Feasibility Test of a Liquid Film Thickness Sensor on a Flexible Printed Circuit Board Using a Three-Electrode Conductance Method

PubMed Central

Lee, Kyu Byung; Kim, Jong Rok; Park, Goon Cherl; Cho, Hyoung Kyu

2016-01-01

Liquid film thickness measurements under temperature-varying conditions in a two-phase flow are of great importance to refining our understanding of two-phase flows. In order to overcome the limitations of the conventional electrical means of measuring the thickness of a liquid film, this study proposes a three-electrode conductance method, with the device fabricated on a flexible printed circuit board (FPCB). The three-electrode conductance method offers the advantage of applicability under conditions with varying temperatures in principle, while the FPCB has the advantage of usability on curved surfaces and in relatively high-temperature conditions in comparison with sensors based on a printed circuit board (PCB). Two types of prototype sensors were fabricated on an FPCB and the feasibility of both was confirmed in a calibration test conducted at different temperatures. With the calibrated sensor, liquid film thickness measurements were conducted via a falling liquid film flow experiment, and the working performance was tested. PMID:28036000

Solution processed flexible organic thin film back-gated transistors based on polyimide dielectric films

NASA Astrophysics Data System (ADS)

Park, Janghoon; Min, Yoonki; Lee, Dongjin

2018-04-01

An organic thin film back-gated transistor (OBGT) was fabricated and characterized. The gate electrode was printed on the back side of substrate, and the dielectric layer was omitted by substituting the dielectric layer with the polyimide (PI) film substrate. Roll-to-roll (R2R) gravure printing, doctor blading, and drop casting methods were used to fabricate the OBGT. The printed OBGT device shows better performance compared with an OTFT device based on dielectric layer of BaTiO3. Additionally, a calendering process enhanced the performance by a factor of 3 to 7 (mobility: 0.016 cm2/V.s, on/off ratio: 9.17×103). A bending test was conducted to confirm the flexibility and durability of the OBGT device. The results show the fabricated device endures 20000-cyclic motions. The realized OBGT device was successfully fabricated and working, which is meaningful for production engineering from the viewpoint of process development.

Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures.

PubMed

Jia, Chao; Bian, Huiyang; Gao, Tingting; Jiang, Feng; Kierzewski, Iain Michael; Wang, Yilin; Yao, Yonggang; Chen, Liheng; Shao, Ziqiang; Zhu, J Y; Hu, Liangbing

2017-08-30

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used cellulose nanocrystals from sulfuric acid hydrolysis, DM-OA-CNCs show several advantages including large aspect ratio, carboxylated surface, and excellent thermal stability along with high yield. We also successfully demonstrate the fabrication of high-performance films and 3D-printed patterns using DM-OA-CNCs. The high-performance films with high transparency, ultralow haze, and excellent thermal stability have the great potential for applications in flexible electronic devices. The 3D-printed patterns with porous structures can be potentially applied in the field of tissue engineering as scaffolds.

Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications.

PubMed

Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

2013-03-01

Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

Large Area Nano-transfer Printing of Sub-50-nm Metal Nanostructures Using Low-cost Semi-flexible Hybrid Templates

NASA Astrophysics Data System (ADS)

Nagel, Robin D.; Haeberle, Tobias; Schmidt, Morten; Lugli, Paolo; Scarpa, Giuseppe

2016-03-01

In this work, we present a method for printing metal micro- and nanopatterns down to sub-50-nm feature sizes using replicated, defect-tolerant stamps made out of OrmoStamp®; material. The relevant parameters for a successful transfer over large areas were investigated and yields above 99 % have been achieved. Comparing our results to conventional nano-transfer printing using PDMS stamps, we find that the more rigid hybrid polymer used here prevents unintended transfer from interspaces between structures of large distance due to roof collapse and deformation of nano-sized structures due to lateral collapse. Yet, our stamps are flexible enough to ensure intimate contact with the underlying substrate over large areas even in the presence of defect particles. Additionally, the presented patterning technique is resist-, solvent-, and chemical-free and is therefore ideally suited for applications in organic nanoelectronics where standard nanostructuring methods can harm or destroy the organic material.

A stable solution-processed polymer semiconductor with record high-mobility for printed transistors

PubMed Central

Li, Jun; Zhao, Yan; Tan, Huei Shuan; Guo, Yunlong; Di, Chong-An; Yu, Gui; Liu, Yunqi; Lin, Ming; Lim, Suo Hon; Zhou, Yuhua; Su, Haibin; Ong, Beng S.

2012-01-01

Microelectronic circuits/arrays produced via high-speed printing instead of traditional photolithographic processes offer an appealing approach to creating the long-sought after, low-cost, large-area flexible electronics. Foremost among critical enablers to propel this paradigm shift in manufacturing is a stable, solution-processable, high-performance semiconductor for printing functionally capable thin-film transistors — fundamental building blocks of microelectronics. We report herein the processing and optimisation of solution-processable polymer semiconductors for thin-film transistors, demonstrating very high field-effect mobility, high on/off ratio, and excellent shelf-life and operating stabilities under ambient conditions. Exceptionally high-gain inverters and functional ring oscillator devices on flexible substrates have been demonstrated. This optimised polymer semiconductor represents a significant progress in semiconductor development, dispelling prevalent skepticism surrounding practical usability of organic semiconductors for high-performance microelectronic devices, opening up application opportunities hitherto functionally or economically inaccessible with silicon technologies, and providing an excellent structural framework for fundamental studies of charge transport in organic systems. PMID:23082244

Executive functioning and reading achievement in school: a study of Brazilian children assessed by their teachers as "poor readers".

PubMed

Engel de Abreu, Pascale M J; Abreu, Neander; Nikaedo, Carolina C; Puglisi, Marina L; Tourinho, Carlos J; Miranda, Mônica C; Befi-Lopes, Debora M; Bueno, Orlando F A; Martin, Romain

2014-01-01

This study examined executive functioning and reading achievement in 106 6- to 8-year-old Brazilian children from a range of social backgrounds of whom approximately half lived below the poverty line. A particular focus was to explore the executive function profile of children whose classroom reading performance was judged below standard by their teachers and who were matched to controls on chronological age, sex, school type (private or public), domicile (Salvador/BA or São Paulo/SP) and socioeconomic status. Children completed a battery of 12 executive function tasks that were conceptual tapping cognitive flexibility, working memory, inhibition and selective attention. Each executive function domain was assessed by several tasks. Principal component analysis extracted four factors that were labeled "Working Memory/Cognitive Flexibility," "Interference Suppression," "Selective Attention," and "Response Inhibition." Individual differences in executive functioning components made differential contributions to early reading achievement. The Working Memory/Cognitive Flexibility factor emerged as the best predictor of reading. Group comparisons on computed factor scores showed that struggling readers displayed limitations in Working Memory/Cognitive Flexibility, but not in other executive function components, compared to more skilled readers. These results validate the account that working memory capacity provides a crucial building block for the development of early literacy skills and extends it to a population of early readers of Portuguese from Brazil. The study suggests that deficits in working memory/cognitive flexibility might represent one contributing factor to reading difficulties in early readers. This might have important implications for how educators might intervene with children at risk of academic under achievement.

Energy-band engineering for tunable memory characteristics through controlled doping of reduced graphene oxide.

PubMed

Han, Su-Ting; Zhou, Ye; Yang, Qing Dan; Zhou, Li; Huang, Long-Biao; Yan, Yan; Lee, Chun-Sing; Roy, Vellaisamy A L

2014-02-25

Tunable memory characteristics are used in multioperational mode circuits where memory cells with various functionalities are needed in one combined device. It is always a challenge to obtain control over threshold voltage for multimode operation. On this regard, we use a strategy of shifting the work function of reduced graphene oxide (rGO) in a controlled manner through doping gold chloride (AuCl3) and obtained a gradient increase of rGO work function. By inserting doped rGO as floating gate, a controlled threshold voltage (Vth) shift has been achieved in both p- and n-type low voltage flexible memory devices with large memory window (up to 4 times for p-type and 8 times for n-type memory devices) in comparison with pristine rGO floating gate memory devices. By proper energy band engineering, we demonstrated a flexible floating gate memory device with larger memory window and controlled threshold voltage shifts.

3D Printing of NinjaFlex Filament onto PEDOT:PSS-Coated Textile Fabrics for Electroluminescence Applications

NASA Astrophysics Data System (ADS)

Tadesse, Melkie Getnet; Dumitrescu, Delia; Loghin, Carmen; Chen, Yan; Wang, Lichuan; Nierstrasz, Vincent

2018-03-01

Electroluminescence (EL) is the property of a semiconductor material pertaining to emitting light in response to an electrical current or a strong electric field. The purpose of this paper is to develop a flexible and lightweight EL device. Thermogravimetric analysis (TGA) was conducted to observe the thermal degradation behavior of NinjaFlex. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)—PEDOT:PSS—with ethylene glycol (EG) was coated onto polyester fabric where NinjaFlex was placed onto the coated fabric using three-dimensional (3D) printing and phosphor paste, and BendLay filaments were subsequently coated via 3D printing. Adhesion strength and flexibility of the 3D-printed NinjaFlex on textile fabrics were investigated. The TGA results of the NinjaFlex depict no weight loss up to 150°C and that the NinjaFlex was highly conductive with a surface resistance value of 8.5 ohms/sq.; the coated fabric exhibited a uniform surface appearance as measured and observed by using four-probe measurements and scanning electron microscopy, respectively, at 60% PEDOT:PSS. The results of the adhesion test showed that peel strengths of 4160 N/m and 3840 N/m were recorded for polyester and cotton specimens, respectively. No weight loss was recorded following three washing cycles of NinjaFlex. The bending lengths were increased by only a factor of 0.082 and 0.577 for polyester and cotton samples at 0.1-mm thickness, respectively; this remains sufficiently flexible to be integrated into textiles. The prototype device emitted light with a 12-V alternating current power supply.

One-Step Interface Engineering for All-Inkjet-Printed, All-Organic Components in Transparent, Flexible Transistors and Inverters: Polymer Binding.

PubMed

Ha, Jewook; Chung, Seungjun; Pei, Mingyuan; Cho, Kilwon; Yang, Hoichang; Hong, Yongtaek

2017-03-15

We report a one-step interface engineering methodology which can be used on both polymer electrodes and gate dielectric for all-inkjet-printed, flexible, transparent organic thin-film transistors (OTFTs) and inverters. Dimethylchlorosilane-terminated polystyrene (PS) was introduced as a surface modifier to cured poly(4-vinylphenol) dielectric and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) electrodes without any pretreatment. On the untreated and PS interlayer-treated dielectric and electrode surfaces, 6,13-bis(triisopropylsilylethynyl)pentacene was printed to fabricate OTFTs and inverters. With the benefit of the PS interlayer, the electrical properties of the OTFTs on a flexible plastic substrate were significantly improved, as shown by a field-effect mobility (μ FET ) of 0.27 cm 2  V -1  s -1 and an on/off current ratio (I on /I off ) of greater than 10 6 . In contrast, the untreated systems showed a low μ FET of less than 0.02 cm 2  V -1  s -1 and I on /I off ∼ 10 4 . Additionally, the all-inkjet-printed inverters based on the PS-modified surfaces exhibited a voltage gain of 7.17 V V -1 . The all-organic-based TFTs and inverters, including deformable and transparent PEDOT:PSS electrodes with a sheet resistance of 160-250 Ω sq -1 , exhibited a light transmittance of higher than 70% (at wavelength of 550 nm). Specifically, there was no significant degradation in the electrical performance of the interface engineering-assisted system after 1000 bending cycles at a radius of 5 mm.

Presentation format effects in a levels-of-processing task.

PubMed

Foos, Paul W; Goolkasian, Paula

2008-01-01

Three experiments were conducted to examine better performance in long-term memory when stimulus items are pictures or spoken words compared to printed words. Hypotheses regarding the allocation of attention to printed words, the semantic link between pictures and processing, and a rich long-term representation for pictures were tested. Using levels-of-processing tasks eliminated format effects when no memory test was expected and processing was deep (El), and when study and test formats did not match (E3). Pictures produced superior performance when a memory test was expected (El & 2) and when study and test formats were the same (E3). Results of all experiments support the attenuation of attention model and that picture superiority is due to a more direct access to semantic processing and a richer visual code. General principles to guide the processing of stimulus information are discussed.

Emerging Carbon and Post-Carbon Nanomaterial Inks for Printed Electronics.

PubMed

Secor, Ethan B; Hersam, Mark C

2015-02-19

Carbon and post-carbon nanomaterials present desirable electrical, optical, chemical, and mechanical attributes for printed electronics, offering low-cost, large-area functionality on flexible substrates. In this Perspective, recent developments in carbon nanomaterial inks are highlighted. Monodisperse semiconducting single-walled carbon nanotubes compatible with inkjet and aerosol jet printing are ideal channels for thin-film transistors, while inkjet, gravure, and screen-printable graphene-based inks are better-suited for electrodes and interconnects. Despite the high performance achieved in prototype devices, additional effort is required to address materials integration issues encountered in more complex systems. In this regard, post-carbon nanomaterial inks (e.g., electrically insulating boron nitride and optically active transition-metal dichalcogenides) present promising opportunities. Finally, emerging work to extend these nanomaterial inks to three-dimensional printing provides a path toward nonplanar devices. Overall, the superlative properties of these materials, coupled with versatile assembly by printing techniques, offer a powerful platform for next-generation printed electronics.

Indirect X-ray Detectors Based on Inkjet-Printed Photodetectors with a Screen-Printed Scintillator Layer.

PubMed

Oliveira, Juliana; Correia, Vitor; Sowade, Enrico; Etxebarria, Ikerne; Rodriguez, Raul D; Mitra, Kalyan Y; Baumann, Reinhard R; Lanceros-Mendez, Senentxu

2018-04-18

Organic photodetectors (PDs) based on printing technologies will allow to expand the current field of PD applications toward large-area and flexible applications in areas such as medical imaging, security, and quality control, among others. Inkjet printing is a powerful digital tool for the deposition of smart and functional materials on various substrates, allowing the development of electronic devices such as PDs on various substrates. In this work, inkjet-printed PD arrays, based on the organic thin-film transistor architecture, have been developed and applied for the indirect detection of X-ray radiation using a scintillator ink as an X-ray absorber. The >90% increase of the photocurrent of the PDs under X-ray radiation, from about 53 nA without the scintillator film to about 102 nA with the scintillator located on top of the PD, proves the suitability of the developed printed device for X-ray detection applications.

Nanoparticle chemisorption printing technique for conductive silver patterning with submicron resolution

PubMed Central

Yamada, Toshikazu; Fukuhara, Katsuo; Matsuoka, Ken; Minemawari, Hiromi; Tsutsumi, Jun'ya; Fukuda, Nobuko; Aoshima, Keisuke; Arai, Shunto; Makita, Yuichi; Kubo, Hitoshi; Enomoto, Takao; Togashi, Takanari; Kurihara, Masato; Hasegawa, Tatsuo

2016-01-01

Silver nanocolloid, a dense suspension of ligand-encapsulated silver nanoparticles, is an important material for printing-based device production technologies. However, printed conductive patterns of sufficiently high quality and resolution for industrial products have not yet been achieved, as the use of conventional printing techniques is severely limiting. Here we report a printing technique to manufacture ultrafine conductive patterns utilizing the exclusive chemisorption phenomenon of weakly encapsulated silver nanoparticles on a photoactivated surface. The process includes masked irradiation of vacuum ultraviolet light on an amorphous perfluorinated polymer layer to photoactivate the surface with pendant carboxylate groups, and subsequent coating of alkylamine-encapsulated silver nanocolloids, which causes amine–carboxylate conversion to trigger the spontaneous formation of a self-fused solid silver layer. The technique can produce silver patterns of submicron fineness adhered strongly to substrates, thus enabling manufacture of flexible transparent conductive sheets. This printing technique could replace conventional vacuum- and photolithography-based device processing. PMID:27091238

Fully Printable Organic and Perovskite Solar Cells with Transfer-Printed Flexible Electrodes.

PubMed

Li, Xianqiang; Tang, Xiaohong; Ye, Tao; Wu, Dan; Wang, Hong; Wang, Xizu

2017-06-07

The perovskite solar cells (PSCs) and organic solar cells (OSCs) with high performance were fabricated with transfer-printed top metal electrodes. We have demonstrated that PSCs and OSCs with the top Au electrodes fabricated by using the transfer printing method have comparable or better performance than the devices with the top Au electrodes fabricated by using the conventional thermal evaporation method. The highest PCE of the PSCs and OSCs with the top electrodes fabricated using the transfer printing method achieved 13.72% and 2.35%, respectively. It has been investigated that fewer defects between the organic thin films and Au electrodes exist by using the transfer printing method which improved the device stability. After storing the PSCs and OSCs with the transfer-printed electrodes in a nitrogen environment for 97 and 103 days without encapsulation, the PSCs and OSCs still retained 71% and 91% of their original PCEs, respectively.

Direct Observation of a Carbon Filament in Water-Resistant Organic Memory.

PubMed

Lee, Byung-Hyun; Bae, Hagyoul; Seong, Hyejeong; Lee, Dong-Il; Park, Hongkeun; Choi, Young Joo; Im, Sung-Gap; Kim, Sang Ouk; Choi, Yang-Kyu

2015-07-28

The memory for the Internet of Things (IoT) requires versatile characteristics such as flexibility, wearability, and stability in outdoor environments. Resistive random access memory (RRAM) to harness a simple structure and organic material with good flexibility can be an attractive candidate for IoT memory. However, its solution-oriented process and unclear switching mechanism are critical problems. Here we demonstrate iCVD polymer-intercalated RRAM (i-RRAM). i-RRAM exhibits robust flexibility and versatile wearability on any substrate. Stable operation of i-RRAM, even in water, is demonstrated, which is the first experimental presentation of water-resistant organic memory without any waterproof protection package. Moreover, the direct observation of a carbon filament is also reported for the first time using transmission electron microscopy, which puts an end to the controversy surrounding the switching mechanism. Therefore, reproducibility is feasible through comprehensive modeling. Furthermore, a carbon filament is superior to a metal filament in terms of the design window and selection of the electrode material. These results suggest an alternative to solve the critical issues of organic RRAM and an optimized memory type suitable for the IoT era.

Transparent resistive switching memory using aluminum oxide on a flexible substrate

NASA Astrophysics Data System (ADS)

Yeom, Seung-Won; Shin, Sang-Chul; Kim, Tan-Young; Ha, Hyeon Jun; Lee, Yun-Hi; Shim, Jae Won; Ju, Byeong-Kwon

2016-02-01

Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices.

Flexible graphene-PZT ferroelectric nonvolatile memory.

PubMed

Lee, Wonho; Kahya, Orhan; Toh, Chee Tat; Ozyilmaz, Barbaros; Ahn, Jong-Hyun

2013-11-29

We report the fabrication of a flexible graphene-based nonvolatile memory device using Pb(Zr0.35,Ti0.65)O3 (PZT) as the ferroelectric material. The graphene and PZT ferroelectric layers were deposited using chemical vapor deposition and sol–gel methods, respectively. Such PZT films show a high remnant polarization (Pr) of 30 μC cm−2 and a coercive voltage (Vc) of 3.5 V under a voltage loop over ±11 V. The graphene–PZT ferroelectric nonvolatile memory on a plastic substrate displayed an on/off current ratio of 6.7, a memory window of 6 V and reliable operation. In addition, the device showed one order of magnitude lower operation voltage range than organic-based ferroelectric nonvolatile memory after removing the anti-ferroelectric behavior incorporating an electrolyte solution. The devices showed robust operation in bent states of bending radii up to 9 mm and in cycling tests of 200 times. The devices exhibited remarkable mechanical properties and were readily integrated with plastic substrates for the production of flexible circuits.

Flexible Organic Tribotronic Transistor Memory for a Visible and Wearable Touch Monitoring System.

PubMed

Li, Jing; Zhang, Chi; Duan, Lian; Zhang, Li Min; Wang, Li Duo; Dong, Gui Fang; Wang, Zhong Lin

2016-01-06

A new type of flexible organic tribotronic transistor memory is proposed, which can be written and erased by externally applied touch actions as an active memory. By further coupling with an organic light-emitting diode (OLED), a visible and wearable touch monitoring system is achieved, in which touch triggering can be memorized and shown as the emission from the OLED. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The strain and thermal induced tunable charging phenomenon in low power flexible memory arrays with a gold nanoparticle monolayer.

PubMed

Zhou, Ye; Han, Su-Ting; Xu, Zong-Xiang; Roy, V A L

2013-03-07

The strain and temperature dependent memory effect of organic memory transistors on plastic substrates has been investigated under ambient conditions. The gold (Au) nanoparticle monolayer was prepared and embedded in an atomic layer deposited aluminum oxide (Al(2)O(3)) as the charge trapping layer. The devices exhibited low operation voltage, reliable memory characteristics and long data retention time. Experimental analysis of the programming and erasing behavior at various bending states showed the relationship between strain and charging capacity. Thermal-induced effects on these memory devices have also been analyzed. The mobility shows ~200% rise and the memory window increases from 1.48 V to 1.8 V when the temperature rises from 20 °C to 80 °C due to thermally activated transport. The retention capability of the devices decreases with the increased working temperature. Our findings provide a better understanding of flexible organic memory transistors under various operating temperatures and validate their applications in various areas such as temperature sensors, temperature memory or advanced electronic circuits. Furthermore, the low temperature processing procedures of the key elements (Au nanoparticle monolayer and Al(2)O(3) dielectric layer) could be potentially integrated with large area flexible electronics.

Printed photodetectors

NASA Astrophysics Data System (ADS)

Pace, Giuseppina; Grimoldi, Andrea; Sampietro, Marco; Natali, Dario; Caironi, Mario

2015-10-01

Photodetectors convert light pulses into electrical signals and are fundamental building blocks for any opto-electronic system adopting light as a probe or information carrier. They have widespread technological applications, from telecommunications to sensors in industrial, medical and civil environments. Further opportunities are plastic short-range communications systems, interactive large-area surfaces and light-weight, flexible, digital imagers. These applications would greatly benefit from the cost-effective fabrication processes enabled by printing technology. While organic semiconductors are the most investigated materials for printed photodetectors, and are the main focus of the present review, there are notable examples of other inorganic or hybrid printable semiconductors for opto-electronic systems, such as quantum-dots and nanowires. Here we propose an overview on printed photodetectors, including three-terminal phototransistors. We first give a brief account of the working mechanism of these light sensitive devices, and then we review the recent progress achieved with scalable printing techniques such as screen-printing, inkjet and other non-contact technologies in the development of all-printed or hybrid systems.

3D Printing Multi-Functionality: Embedded RF Antennas and Components

NASA Technical Reports Server (NTRS)

Shemelya, C. M.; Zemba, M.; Liang, M.; Espalin, D.; Kief, C.; Xin, H.; Wicker, R. B.; MacDonald, E. W.

2015-01-01

Significant research and press has recently focused on the fabrication freedom of Additive Manufacturing (AM) to create both conceptual models and final end-use products. This flexibility allows design modifications to be immediately reflected in 3D printed structures, creating new paradigms within the manufacturing process. 3D printed products will inevitably be fabricated locally, with unit-level customization, optimized to unique mission requirements. However, for the technology to be universally adopted, the processes must be enhanced to incorporate additional technologies; such as electronics, actuation, and electromagnetics. Recently, a novel 3D printing platform, Multi3D manufacturing, was funded by the presidential initiative for revitalizing manufacturing in the USA using 3D printing (America Makes - also known as the National Additive Manufacturing Innovation Institute). The Multi3D system specifically targets 3D printed electronics in arbitrary form; and building upon the potential of this system, this paper describes RF antennas and components fabricated through the integration of material extrusion 3D printing with embedded wire, mesh, and RF elements.

3D printing for soft robotics – a review

PubMed Central

Gul, Jahan Zeb; Sajid, Memoon; Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Shah, Imran; Kim, Kyung-Hwan; Lee, Jae-Wook; Choi, Kyung Hyun

2018-01-01

Abstract Soft robots have received an increasing attention due to their advantages of high flexibility and safety for human operators but the fabrication is a challenge. Recently, 3D printing has been used as a key technology to fabricate soft robots because of high quality and printing multiple materials at the same time. Functional soft materials are particularly well suited for soft robotics due to a wide range of stimulants and sensitive demonstration of large deformations, high motion complexities and varied multi-functionalities. This review comprises a detailed survey of 3D printing in soft robotics. The development of key 3D printing technologies and new materials along with composites for soft robotic applications is investigated. A brief summary of 3D-printed soft devices suitable for medical to industrial applications is also included. The growing research on both 3D printing and soft robotics needs a summary of the major reported studies and the authors believe that this review article serves the purpose. PMID:29707065

3D printing for soft robotics - a review.

PubMed

Gul, Jahan Zeb; Sajid, Memoon; Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Shah, Imran; Kim, Kyung-Hwan; Lee, Jae-Wook; Choi, Kyung Hyun

2018-01-01

Soft robots have received an increasing attention due to their advantages of high flexibility and safety for human operators but the fabrication is a challenge. Recently, 3D printing has been used as a key technology to fabricate soft robots because of high quality and printing multiple materials at the same time. Functional soft materials are particularly well suited for soft robotics due to a wide range of stimulants and sensitive demonstration of large deformations, high motion complexities and varied multi-functionalities. This review comprises a detailed survey of 3D printing in soft robotics. The development of key 3D printing technologies and new materials along with composites for soft robotic applications is investigated. A brief summary of 3D-printed soft devices suitable for medical to industrial applications is also included. The growing research on both 3D printing and soft robotics needs a summary of the major reported studies and the authors believe that this review article serves the purpose.

Aerosol-jet-printed, 1 volt H-bridge drive circuit on plastic with integrated electrochromic pixel.

PubMed

Ha, Mingjing; Zhang, Wei; Braga, Daniele; Renn, Michael J; Kim, Chris H; Frisbie, C Daniel

2013-12-26

In this report, we demonstrate a printed, flexible, and low-voltage circuit that successfully drives a polymer electrochromic (EC) pixel as large as 4 mm(2) that is printed on the same substrate. All of the key components of the drive circuitry, namely, resistors, capacitors, and transistors, were aerosol-jet-printed onto a plastic foil; metallic electrodes and interconnects were the only components prepatterned on the plastic by conventional photolithography. The large milliampere drive currents necessary to switch a 4 mm(2) EC pixel were controlled by printed electrolyte-gated transistors (EGTs) that incorporate printable ion gels for the gate insulator layers and poly(3-hexylthiophene) for the semiconductor channels. Upon application of a 1 V input pulse, the circuit switches the printed EC pixel ON (red) and OFF (blue) two times in approximately 4 s. The performance of the circuit and the behavior of the individual resistors, capacitors, EGTs, and the EC pixel are analyzed as functions of the printing parameters and operating conditions.

Sorting of large-diameter semiconducting carbon nanotube and printed flexible driving circuit for organic light emitting diode (OLED)

NASA Astrophysics Data System (ADS)

Xu, Wenya; Zhao, Jianwen; Qian, Long; Han, Xianying; Wu, Liangzhuan; Wu, Weichen; Song, Minshun; Zhou, Lu; Su, Wenming; Wang, Chao; Nie, Shuhong; Cui, Zheng

2014-01-01

A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10-3 A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 104 and output current up to 3.5 × 10-4 A at Vscan = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications.A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10-3 A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 104 and output current up to 3.5 × 10-4 A at Vscan = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr04870e

Naps promote flexible memory retrieval in 12-month-old infants.

PubMed

Konrad, Carolin; Seehagen, Sabine; Schneider, Silvia; Herbert, Jane S

2016-11-01

Flexibility in applying existing knowledge to similar cues is a corner stone of memory development in infants. Here, we examine the effect of sleep on the flexibility of memory retrieval using a deferred imitation paradigm. Forty-eight 12-month-old infants were randomly assigned to either a nap or a no-nap demonstration condition (scheduled around their natural daytime sleep schedule) or to a baseline control condition. In the demonstration conditions, infants watched an experimenter perform three target actions on a hand puppet. Immediately afterwards, infants were allowed to practice the target actions three times. In a test session 4-hr later, infants were given the opportunity to reproduce the actions with a novel hand puppet differing in color from the puppet used during the demonstration session. Only infants in the nap-condition performed significantly more target actions than infants in the baseline control condition. Furthermore, they were faster to carry out the first target action than infants in the no-nap condition. We conclude that sleep had a facilitative effect on infants' flexibility of memory retrieval. © 2016 Wiley Periodicals, Inc.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference.

PubMed

Zeithamova, Dagmar; Dominick, April L; Preston, Alison R

2012-07-12

Memory enables flexible use of past experience to inform new behaviors. Although leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants' ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. Copyright © 2012 Elsevier Inc. All rights reserved.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference

PubMed Central

Zeithamova, Dagmar; Dominick, April L.; Preston, Alison R.

2012-01-01

SUMMARY Memory enables flexible use of past experience to inform new behaviors. Though leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants’ ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. PMID:22794270

Flexible circuits with integrated switches for robotic shape sensing

NASA Astrophysics Data System (ADS)

Harnett, C. K.

2016-05-01

Digital switches are commonly used for detecting surface contact and limb-position limits in robotics. The typical momentary-contact digital switch is a mechanical device made from metal springs, designed to connect with a rigid printed circuit board (PCB). However, flexible printed circuits are taking over from the rigid PCB in robotics because the circuits can bend while carrying signals and power through moving joints. This project is motivated by a previous work where an array of surface-mount momentary contact switches on a flexible circuit acted as an all-digital shape sensor compatible with the power resources of energy harvesting systems. Without a rigid segment, the smallest commercially-available surface-mount switches would detach from the flexible circuit after several bending cycles, sometimes violently. This report describes a low-cost, conductive fiber based method to integrate electromechanical switches into flexible circuits and other soft, bendable materials. Because the switches are digital (on/off), they differ from commercially-available continuous-valued bend/flex sensors. No amplification or analog-to-digital conversion is needed to read the signal, but the tradeoff is that the digital switches only give a threshold curvature value. Boundary conditions on the edges of the flexible circuit are key to setting the threshold curvature value for switching. This presentation will discuss threshold-setting, size scaling of the design, automation for inserting a digital switch into the flexible circuit fabrication process, and methods for reconstructing a shape from an array of digital switch states.

The impact of realistic source shape and flexibility on source mask optimization

NASA Astrophysics Data System (ADS)

Aoyama, Hajime; Mizuno, Yasushi; Hirayanagi, Noriyuki; Kita, Naonori; Matsui, Ryota; Izumi, Hirohiko; Tajima, Keiichi; Siebert, Joachim; Demmerle, Wolfgang; Matsuyama, Tomoyuki

2013-04-01

Source mask optimization (SMO) is widely used to make state-of-the-art semiconductor devices in high volume manufacturing. To realize mature SMO solutions in production, the Intelligent Illuminator, which is an illumination system on Nikon scanner, is useful because it can provide generation of freeform sources with high fidelity to the target. Proteus SMO, which employs co-optimization method and an insertion of validation with mask 3D effect and resist properties for an accurate prediction of wafer printing, can take into account the properties of Intelligent Illuminator. We investigate an impact of the source properties on the SMO to pattern of a static-random access memory. Quality of a source made on the scanner compared to the SMO target is evaluated with in-situ measurement and aerial image simulation using its measurement data. Furthermore we discuss an evaluation of a universality of the source to use it in multiple scanners with a validation with estimated value of scanner errors.

Moisture absorption and bakeout characteristics of rigid-flexible multilayer printed wiring boards

NASA Astrophysics Data System (ADS)

Lula, J. W.

1991-01-01

Moisture absorption and bakeout characteristics of rigid flexible printed wiring boards were determined. It was found that test specimens had absorbed 0.95 weight percent moisture when equilibrated to a 50 percent RH, 25 C environment. Heating those equilibrated specimens in a 120 C static air oven removed 92 percent of this absorbed moisture in 24 h. Heating the samples in a 80 C static air oven removed only 64 percent of the absorbed moisture at the end of 24 h. A 120 C vacuum bake removed moisture at essentially the same rate with parylene slowed the absorption rate by approximately 50 percent but did not appreciably affect the equilibrium moisture content or the drying rate.

The strain and thermal induced tunable charging phenomenon in low power flexible memory arrays with a gold nanoparticle monolayer

NASA Astrophysics Data System (ADS)

Zhou, Ye; Han, Su-Ting; Xu, Zong-Xiang; Roy, V. A. L.

2013-02-01

The strain and temperature dependent memory effect of organic memory transistors on plastic substrates has been investigated under ambient conditions. The gold (Au) nanoparticle monolayer was prepared and embedded in an atomic layer deposited aluminum oxide (Al2O3) as the charge trapping layer. The devices exhibited low operation voltage, reliable memory characteristics and long data retention time. Experimental analysis of the programming and erasing behavior at various bending states showed the relationship between strain and charging capacity. Thermal-induced effects on these memory devices have also been analyzed. The mobility shows ~200% rise and the memory window increases from 1.48 V to 1.8 V when the temperature rises from 20 °C to 80 °C due to thermally activated transport. The retention capability of the devices decreases with the increased working temperature. Our findings provide a better understanding of flexible organic memory transistors under various operating temperatures and validate their applications in various areas such as temperature sensors, temperature memory or advanced electronic circuits. Furthermore, the low temperature processing procedures of the key elements (Au nanoparticle monolayer and Al2O3 dielectric layer) could be potentially integrated with large area flexible electronics.The strain and temperature dependent memory effect of organic memory transistors on plastic substrates has been investigated under ambient conditions. The gold (Au) nanoparticle monolayer was prepared and embedded in an atomic layer deposited aluminum oxide (Al2O3) as the charge trapping layer. The devices exhibited low operation voltage, reliable memory characteristics and long data retention time. Experimental analysis of the programming and erasing behavior at various bending states showed the relationship between strain and charging capacity. Thermal-induced effects on these memory devices have also been analyzed. The mobility shows ~200% rise and the memory window increases from 1.48 V to 1.8 V when the temperature rises from 20 °C to 80 °C due to thermally activated transport. The retention capability of the devices decreases with the increased working temperature. Our findings provide a better understanding of flexible organic memory transistors under various operating temperatures and validate their applications in various areas such as temperature sensors, temperature memory or advanced electronic circuits. Furthermore, the low temperature processing procedures of the key elements (Au nanoparticle monolayer and Al2O3 dielectric layer) could be potentially integrated with large area flexible electronics. Electronic supplementary information (ESI) available: UV-vis spectrum of Au nanoparticle aqueous solution, transfer characteristics of the transistors without inserting an Au nanoparticle monolayer, AFM image of the pentacene layer, transfer characteristics at different program voltages and memory windows with respect to the P/E voltage. See DOI: 10.1039/c2nr32579a

Shape-morphing composites with designed micro-architectures

DOE PAGES

Rodriguez, Jennifer N.; Zhu, Cheng; Duoss, Eric B.; ...

2016-06-15

Shape memory polymers (SMPs) are attractive materials due to their unique mechanical properties, including high deformation capacity and shape recovery. SMPs are easier to process, lightweight, and inexpensive compared to their metallic counterparts, shape memory alloys. However, SMPs are limited to relatively small form factors due to their low recovery stresses. Lightweight, micro-architected composite SMPs may overcome these size limitations and offer the ability to combine functional properties (e.g., electrical conductivity) with shape memory behavior. Fabrication of 3D SMP thermoset structures via traditional manufacturing methods is challenging, especially for designs that are composed of multiple materials within porous microarchitectures designedmore » for specific shape change strategies, e.g. sequential shape recovery. We report thermoset SMP composite inks containing some materials from renewable resources that can be 3D printed into complex, multi-material architectures that exhibit programmable shape changes with temperature and time. Through addition of fiber-based fillers, we demonstrate printing of electrically conductive SMPs where multiple shape states may induce functional changes in a device and that shape changes can be actuated via heating of printed composites. As a result, the ability of SMPs to recover their original shapes will be advantageous for a broad range of applications, including medical, aerospace, and robotic devices.« less

Sequential Self-Folding Structures by 3D Printed Digital Shape Memory Polymers

NASA Astrophysics Data System (ADS)

Mao, Yiqi; Yu, Kai; Isakov, Michael S.; Wu, Jiangtao; Dunn, Martin L.; Jerry Qi, H.

2015-09-01

Folding is ubiquitous in nature with examples ranging from the formation of cellular components to winged insects. It finds technological applications including packaging of solar cells and space structures, deployable biomedical devices, and self-assembling robots and airbags. Here we demonstrate sequential self-folding structures realized by thermal activation of spatially-variable patterns that are 3D printed with digital shape memory polymers, which are digital materials with different shape memory behaviors. The time-dependent behavior of each polymer allows the temporal sequencing of activation when the structure is subjected to a uniform temperature. This is demonstrated via a series of 3D printed structures that respond rapidly to a thermal stimulus, and self-fold to specified shapes in controlled shape changing sequences. Measurements of the spatial and temporal nature of self-folding structures are in good agreement with the companion finite element simulations. A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics. An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding. A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

Direct 4D printing via active composite materials.

PubMed

Ding, Zhen; Yuan, Chao; Peng, Xirui; Wang, Tiejun; Qi, H Jerry; Dunn, Martin L

2017-04-01

We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the design of the architecture and process parameters of a composite consisting of a glassy shape memory polymer and an elastomer that is programmed with a built-in compressive strain during photopolymerization. Upon heating, the shape memory polymer softens, releases the constraint on the strained elastomer, and allows the object to transform into a new permanent shape, which can then be reprogrammed into multiple subsequent shapes. Our key advance, the markedly simplified creation of high-resolution complex 3D reprogrammable structures, promises to enable myriad applications across domains, including medical technology, aerospace, and consumer products, and even suggests a new paradigm in product design, where components are simultaneously designed to inhabit multiple configurations during service.

Compact, high-speed algorithm for laying out printed circuit board runs

NASA Astrophysics Data System (ADS)

Zapolotskiy, D. Y.

1985-09-01

A high speed printed circuit connection layout algorithm is described which was developed within the framework of an interactive system for designing two-sided printed circuit broads. For this reason, algorithm speed was considered, a priori, as a requirement equally as important as the inherent demand for minimizing circuit run lengths and the number of junction openings. This resulted from the fact that, in order to provide psychological man/machine compatibility in the design process, real-time dialog during the layout phase is possible only within limited time frames (on the order of several seconds) for each circuit run. The work was carried out for use on an ARM-R automated work site complex based on an SM-4 minicomputer with a 32K-word memory. This limited memory capacity heightened the demand for algorithm speed and also tightened data file structure and size requirements. The layout algorithm's design logic is analyzed. The structure and organization of the data files are described.

Direct 4D printing via active composite materials

PubMed Central

Ding, Zhen; Yuan, Chao; Peng, Xirui; Wang, Tiejun; Qi, H. Jerry; Dunn, Martin L.

2017-01-01

We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the design of the architecture and process parameters of a composite consisting of a glassy shape memory polymer and an elastomer that is programmed with a built-in compressive strain during photopolymerization. Upon heating, the shape memory polymer softens, releases the constraint on the strained elastomer, and allows the object to transform into a new permanent shape, which can then be reprogrammed into multiple subsequent shapes. Our key advance, the markedly simplified creation of high-resolution complex 3D reprogrammable structures, promises to enable myriad applications across domains, including medical technology, aerospace, and consumer products, and even suggests a new paradigm in product design, where components are simultaneously designed to inhabit multiple configurations during service. PMID:28439560

Inkjet-/3D-/4D-printed autonomous wearable RF modules for biomonitoring, positioning and sensing applications

NASA Astrophysics Data System (ADS)

Bito, Jo; Bahr, Ryan; Hester, Jimmy; Kimionis, John; Nauroze, Abdullah; Su, Wenjing; Tehrani, Bijan; Tentzeris, Manos M.

2017-05-01

In this paper, numerous inkjet-/3D-/4D-printed wearable flexible antennas, RF electronics, modules and sensors fabricated on paper and other polymer (e.g. LCP) substrates are introduced as a system-level solution for ultra-low-cost mass production of autonomous Biomonitoring, Positioning and Sensing applications. This paper briefly discusses the state-of-the-art area of fully-integrated wearable wireless sensor modules on paper or flexible LCP and show the first ever 4D sensor module integration on paper, as well as numerous 3D and 4D multilayer paper-based and LCP-based RF/microwave, flexible and wearable structures, that could potentially set the foundation for the truly convergent wireless sensor ad-hoc "on-body networks of the future with enhanced cognitive intelligence and "rugged" packaging. Also, some challenges concerning the power sources of "nearperpetual" wearable RF modules, including flexible miniaturized batteries as well as power-scavenging approaches involving electromagnetic and solar energy forms are discuessed. The final step of the paper will involve examples from mmW wearable (e.g. biomonitoring) antennas and RF modules, as well as the first examples of the integration of inkjet-printed nanotechnology-based (e.g.CNT) sensors on paper and organic substrates for Internet of Things (IoT) applications. It has to be noted that the paper will review and present challenges for inkjetprinted organic active and nonlinear devices as well as future directions in the area of environmentally-friendly "green") wearable RF electronics and "smart-skin conformal sensors.

All-printed diode operating at 1.6 GHz

PubMed Central

Sani, Negar; Robertsson, Mats; Cooper, Philip; Wang, Xin; Svensson, Magnus; Andersson Ersman, Peter; Norberg, Petronella; Nilsson, Marie; Nilsson, David; Liu, Xianjie; Hesselbom, Hjalmar; Akesso, Laurent; Fahlman, Mats; Crispin, Xavier; Engquist, Isak; Berggren, Magnus; Gustafsson, Göran

2014-01-01

Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications. PMID:25002504

Inkjet-Printed Biofunctional Thermo-Plasmonic Interfaces for Patterned Neuromodulation.

PubMed

Kang, Hongki; Lee, Gu-Haeng; Jung, Hyunjun; Lee, Jee Woong; Nam, Yoonkey

2018-02-27

Localized heat generation by the thermo-plasmonic effect of metal nanoparticles has great potential in biomedical engineering research. Precise patterning of the nanoparticles using inkjet printing can enable the application of the thermo-plasmonic effect in a well-controlled way (shape and intensity). However, a universally applicable inkjet printing process that allows good control in patterning and assembly of nanoparticles with good biocompatibility is missing. Here we developed inkjet-printing-based biofunctional thermo-plasmonic interfaces that can modulate biological activities. We found that inkjet printing of plasmonic nanoparticles on a polyelectrolyte layer-by-layer substrate coating enables high-quality, biocompatible thermo-plasmonic interfaces across various substrates (rigid/flexible, hydrophobic/hydrophilic) by induced contact line pinning and electrostatically assisted nanoparticle assembly. We experimentally confirmed that the generated heat from the inkjet-printed thermo-plasmonic patterns can be applied in micrometer resolution over a large area. Lastly, we demonstrated that the patterned thermo-plasmonic effect from the inkjet-printed gold nanorods can selectively modulate neuronal network activities. This inkjet printing process therefore can be a universal method for biofunctional thermo-plasmonic interfaces in various bioengineering applications.

Flexible attention allocation to visual and auditory working memory tasks: manipulating reward induces a trade-off.

PubMed

Morey, Candice Coker; Cowan, Nelson; Morey, Richard D; Rouder, Jeffery N

2011-02-01

Prominent roles for general attention resources are posited in many models of working memory, but the manner in which these can be allocated differs between models or is not sufficiently specified. We varied the payoffs for correct responses in two temporally-overlapping recognition tasks, a visual array comparison task and a tone sequence comparison task. In the critical conditions, an increase in reward for one task corresponded to a decrease in reward for the concurrent task, but memory load remained constant. Our results show patterns of interference consistent with a trade-off between the tasks, suggesting that a shared resource can be flexibly divided, rather than only fully allotted to either of the tasks. Our findings support a role for a domain-general resource in models of working memory, and furthermore suggest that this resource is flexibly divisible.

Towards microscale electrohydrodynamic three-dimensional printing

NASA Astrophysics Data System (ADS)

He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

2016-02-01

It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics.

3D Printed Multimaterial Microfluidic Valve

PubMed Central

Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

2016-01-01

We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

Memory flexibility training for autobiographical memory as an intervention for maintaining social and mental well-being in older adults.

PubMed

Leahy, Fiona; Ridout, Nathan; Holland, Carol

2018-05-07

Autobiographical memory specificity (AMS) reduces with increasing age and is associated with depression, social problem-solving and functional limitations. However, ability to switch between general and specific, as well as between positive and negative retrieval, may be more important for the strategic use of autobiographical information in everyday life. Ability to switch between retrieval modes is likely to rely on aspects of executive function. We propose that age-related deficits in cognitive flexibility impair AMS, but the "positivity effect" protects positively valenced memories from impaired specificity. A training programme to improve the ability to flexibly retrieve different types of memories in depressed adults (MemFlex) was examined in non-depressed older adults to determine effects on AMS, valence and the executive functions underlying cognitive flexibility. Thirty-nine participants aged 70+ (MemFlex, n = 20; control, n = 19) took part. AMS and the inhibition aspect of executive function improved in both groups, suggesting these abilities are amenable to change, although not differentially affected by this type of training. Lower baseline inhibition scores correlated with increased negative, but not positive AMS, suggesting that positive AMS is an automatic process in older adults. Changes in AMS correlated with changes in social problem-solving, emphasising the usefulness of AMs in a social environment.

Executive functioning and reading achievement in school: a study of Brazilian children assessed by their teachers as “poor readers”

PubMed Central

Engel de Abreu, Pascale M. J.; Abreu, Neander; Nikaedo, Carolina C.; Puglisi, Marina L.; Tourinho, Carlos J.; Miranda, Mônica C.; Befi-Lopes, Debora M.; Bueno, Orlando F. A.; Martin, Romain

2014-01-01

This study examined executive functioning and reading achievement in 106 6- to 8-year-old Brazilian children from a range of social backgrounds of whom approximately half lived below the poverty line. A particular focus was to explore the executive function profile of children whose classroom reading performance was judged below standard by their teachers and who were matched to controls on chronological age, sex, school type (private or public), domicile (Salvador/BA or São Paulo/SP) and socioeconomic status. Children completed a battery of 12 executive function tasks that were conceptual tapping cognitive flexibility, working memory, inhibition and selective attention. Each executive function domain was assessed by several tasks. Principal component analysis extracted four factors that were labeled “Working Memory/Cognitive Flexibility,” “Interference Suppression,” “Selective Attention,” and “Response Inhibition.” Individual differences in executive functioning components made differential contributions to early reading achievement. The Working Memory/Cognitive Flexibility factor emerged as the best predictor of reading. Group comparisons on computed factor scores showed that struggling readers displayed limitations in Working Memory/Cognitive Flexibility, but not in other executive function components, compared to more skilled readers. These results validate the account that working memory capacity provides a crucial building block for the development of early literacy skills and extends it to a population of early readers of Portuguese from Brazil. The study suggests that deficits in working memory/cognitive flexibility might represent one contributing factor to reading difficulties in early readers. This might have important implications for how educators might intervene with children at risk of academic under achievement. PMID:24959155

The Effect of Colour-Word Interference on Children's Memory for Words.

ERIC Educational Resources Information Center

Malliet, Gineva M.

The Stroop color-word test involves a conflict situation in which subjects are asked to say aloud the ink color used to print a color word on a card. Interference occurs when the ink color is in conflict with the color word, such as 'red' printed in green ink. On the other hand, little interference occurs when asked to name the color words…

Race Talk and School Equity in Local Print Media: The Discursive Flexibility of Whiteness and the Promise of Race-Conscious Talk

ERIC Educational Resources Information Center

Villenas, Sofia A.; Angeles, Sophia L.

2013-01-01

This article examines how a progressive, rural/small city community in the USA wrestles with race, racism, and school equity in the public arena of print media. It inquires into the tensions, limitations, and possibilities for race-conscious discourse in the face of both explicit racist hate speech and benevolent liberal race talk. Based on…

Printed Carbon Nanotube Electronics and Sensor Systems.

PubMed

Chen, Kevin; Gao, Wei; Emaminejad, Sam; Kiriya, Daisuke; Ota, Hiroki; Nyein, Hnin Yin Yin; Takei, Kuniharu; Javey, Ali

2016-06-01

Printing technologies offer large-area, high-throughput production capabilities for electronics and sensors on mechanically flexible substrates that can conformally cover different surfaces. These capabilities enable a wide range of new applications such as low-cost disposable electronics for health monitoring and wearables, extremely large format electronic displays, interactive wallpapers, and sensing arrays. Solution-processed carbon nanotubes have been shown to be a promising candidate for such printing processes, offering stable devices with high performance. Here, recent progress made in printed carbon nanotube electronics is discussed in terms of materials, processing, devices, and applications. Research challenges and opportunities moving forward from processing and system-level integration points of view are also discussed for enabling practical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrical properties of solution-deposited ZnO thin-film transistors by low-temperature annealing.

PubMed

Lim, Chul; Oh, Ji Young; Koo, Jae Bon; Park, Chan Woo; Jung, Soon-Won; Na, Bock Soon; Chu, Hye Yong

2014-11-01

Flexible oxide thin-film transistors (Oxide-TFTs) have emerged as next generation transistors because of their applicability in electronic device. In particular, the major driving force behind solution-processed zinc oxide film research is its prospective use in printing for electronics. A low-temperature process to improve the performance of solution-processed n-channel ZnO thin-film transistors (TFTs) fabricated via spin-coating and inkjet-printing is introduced here. ZnO nanoparticles were synthesized using a facile sonochemical method that was slightly modified based on a previously reported method. The influence of the annealing atmosphere on both nanoparticle-based TFT devices fabricated via spin-coating and those created via inkjet printing was investigated. For the inkjet-printed TFTs, the characteristics were improved significantly at an annealing temperature of 150 degrees C. The field effect mobility, V(th), and the on/off current ratios were 3.03 cm2/Vs, -3.3 V, and 10(4), respectively. These results indicate that annealing at 150 degrees C 1 h is sufficient to obtain a mobility (μ(sat)) as high as 3.03 cm2/Vs. Also, the active layer of the solution-based ZnO nanoparticles allowed the production of high-performance TFTs for low-cost, large-area electronics and flexible devices.

Introduction of novel 3D-printed superficial applicators for high-dose-rate skin brachytherapy.

PubMed

Jones, Emma-Louise; Tonino Baldion, Anna; Thomas, Christopher; Burrows, Tom; Byrne, Nick; Newton, Victoria; Aldridge, Sarah

Custom-made surface mold applicators often allow more flexibility when carrying out skin brachytherapy, particularly for small treatment areas with high surface obliquity. They can, however, be difficult to manufacture, particularly if there is a lack of experience in superficial high-dose-rate brachytherapy techniques or with limited resources. We present a novel method of manufacturing superficial brachytherapy applicators utilizing three-dimensional (3D)-printing techniques. We describe the treatment planning process and the process of applicator manufacture. The treatment planning process, with the introduction of a pre-plan, allows for an "ideal" catheter arrangement within an applicator to be determined, exploiting varying catheter orientations, heights, and curvatures if required. The pre-plan arrangement is then 3D printed to the exact specifications of the pre-plan applicator design. This results in improved target volume coverage and improved sparing of organs at risk. Using a pre-plan technique for ideal catheter placement followed by automated 3D-printed applicator manufacture has greatly improved the entire process of superficial high-dose-rate brachytherapy treatment. We are able to design and manufacture flexible, well-fitting, superior quality applicators resulting in a more efficient and improved patient pathway and patient experience. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Laser printed interconnects for flexible electronics

NASA Astrophysics Data System (ADS)

Pique, Alberto; Beniam, Iyoel; Mathews, Scott; Charipar, Nicholas

Laser-induced forward transfer (LIFT) can be used to generate microscale 3D structures for interconnect applications non-lithographically. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or dispersed metallic nanoparticles. However, the resulting 3D structures do not achieve the bulk conductivity of metal interconnects of the same cross-section and length as those formed by wire bonding or tab welding. It is possible, however, to laser transfer entire structures using a LIFT technique known as lase-and-place. Lase-and-place allows whole components and parts to be transferred from a donor substrate onto a desired location with one single laser pulse. This talk will present the use of LIFT to laser print freestanding solid metal interconnects to connect individual devices into functional circuits. Furthermore, the same laser can bend or fold the thin metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief due to flexing or thermal mismatch. Examples of these laser printed 3D metallic bridges and their role in the development of next generation flexible electronics by additive manufacturing will be presented. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

Printable Spacecraft: Flexible Electronic Platforms for NASA Missions. Phase One

NASA Technical Reports Server (NTRS)

Short, Kendra (Principal Investigator); Van Buren, David (Principal Investigator)

2012-01-01

Atmospheric confetti. Inchworm crawlers. Blankets of ground penetrating radar. These are some of the unique mission concepts which could be enabled by a printable spacecraft. Printed electronics technology offers enormous potential to transform the way NASA builds spacecraft. A printed spacecraft's low mass, volume and cost offer dramatic potential impacts to many missions. Network missions could increase from a few discrete measurements to tens of thousands of platforms improving areal density and system reliability. Printed platforms could be added to any prime mission as a low-cost, minimum resource secondary payload to augment the science return. For a small fraction of the mass and cost of a traditional lander, a Europa flagship mission might carry experimental printed surface platforms. An Enceladus Explorer could carry feather-light printed platforms to release into volcanic plumes to measure composition and impact energies. The ability to print circuits directly onto a variety of surfaces, opens the possibility of multi-functional structures and membranes such as "smart" solar sails and balloons. The inherent flexibility of a printed platform allows for in-situ re-configurability for aerodynamic control or mobility. Engineering telemetry of wheel/soil interactions are possible with a conformal printed sensor tape fit around a rover wheel. Environmental time history within a sample return canister could be recorded with a printed sensor array that fits flush to the interior of the canister. Phase One of the NIAC task entitled "Printable Spacecraft" investigated the viability of printed electronics technologies for creating multi-functional spacecraft platforms. Mission concepts and architectures that could be enhanced or enabled with this technology were explored. This final report captures the results and conclusions of the Phase One study. First, the report presents the approach taken in conducting the study and a mapping of results against the proposed Phase One objectives. Then an overview of the general field of printed electronics is provided, including manufacturing approaches, commercial drivers, and the current state of integrated systems. The bulk of the report contains the results and findings of Phase One organized into four sections: a survey of components required for a printable spacecraft, technology roadmaps considerations, science mission and engineering applications, and potential risks and challenges of the technology.

Printing method for organic light emitting device lighting

NASA Astrophysics Data System (ADS)

Ki, Hyun Chul; Kim, Seon Hoon; Kim, Doo-Gun; Kim, Tae-Un; Kim, Snag-Gi; Hong, Kyung-Jin; So, Soon-Yeol

2013-03-01

Organic Light Emitting Device (OLED) has a characteristic to change the electric energy into the light when the electric field is applied to the organic material. OLED is currently employed as a light source for the lighting tools because research has extensively progressed in the improvement of luminance, efficiency, and life time. OLED is widely used in the plate display device because of a simple manufacture process and high emitting efficiency. But most of OLED lighting projects were used the vacuum evaporator (thermal evaporator) with low molecular. Although printing method has lower efficiency and life time of OLED than vacuum evaporator method, projects of printing OLED actively are progressed because was possible to combine with flexible substrate and printing technology. Printing technology is ink-jet, screen printing and slot coating. This printing method allows for low cost and mass production techniques and large substrates. In this research, we have proposed inkjet printing for organic light-emitting devices has the dominant method of thick film deposition because of its low cost and simple processing. In this research, the fabrication of the passive matrix OLED is achieved by inkjet printing, using a polymer phosphorescent ink. We are measured optical and electrical characteristics of OLED.

The role of printing techniques for large-area dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Mariani, Paolo; Vesce, Luigi; Di Carlo, Aldo

2015-10-01

The versatility of printing technologies and their intrinsic ability to outperform other techniques in large-area deposition gives scope to revolutionize the photovoltaic (PV) manufacturing field. Printing methods are commonly used in conventional silicon-based PVs to cover part of the production process. Screen printing techniques, for example, are applied to deposit electrical contacts on the silicon wafer. However, it is with the advent of third generation PVs that printing/coating techniques have been extensively used in almost all of the manufacturing processes. Among all the third generation PVs, dye sensitized solar cell (DSSC) technology has been developed up to commercialization levels. DSSCs and modules can be fabricated by adopting all of the main printing techniques on both rigid and flexible substrates. This allows an easy tuning of cell/module characteristics to the desired application. Transparency, colour, shape, layout and other DSSC’s features can be easily varied by changing the printing parameters and paste/ink formulations used in the printing process. This review focuses on large-area printing/coating technologies for the fabrication of DSSCs devices. The most used and promising techniques are presented underlining the process parameters and applications.

Fabrication of InGaZnO Nonvolatile Memory Devices at Low Temperature of 150 degrees C for Applications in Flexible Memory Displays and Transparency Coating on Plastic Substrates.

PubMed

Hanh, Nguyen Hong; Jang, Kyungsoo; Yi, Junsin

2016-05-01

We directly deposited amorphous InGaZnO (a-IGZO) nonvolatile memory (NVM) devices with oxynitride-oxide-dioxide (OOO) stack structures on plastic substrate by a DC pulsed magnetron sputtering and inductively coupled plasma chemical vapor deposition (ICPCVD) system, using a low-temperature of 150 degrees C. The fabricated bottom gate a-IGZO NVM devices have a wide memory window with a low operating voltage during programming and erasing, due to an effective control of the gate dielectrics. In addition, after ten years, the memory device retains a memory window of over 73%, with a programming duration of only 1 ms. Moreover, the a-IGZO films show high optical transmittance of over 85%, and good uniformity with a root mean square (RMS) roughness of 0.26 nm. This film is a promising candidate to achieve flexible displays and transparency on plastic substrates because of the possibility of low-temperature deposition, and the high transparent properties of a-IGZO films. These results demonstrate that the a-IGZO NVM devices obtained at low-temperature have a suitable programming and erasing efficiency for data storage under low-voltage conditions, in combination with excellent charge retention characteristics, and thus show great potential application in flexible memory displays.

Solution-processed flexible NiO resistive random access memory device

NASA Astrophysics Data System (ADS)

Kim, Soo-Jung; Lee, Heon; Hong, Sung-Hoon

2018-04-01

Non-volatile memories (NVMs) using nanocrystals (NCs) as active materials can be applied to soft electronic devices requiring a low-temperature process because NCs do not require a heat treatment process for crystallization. In addition, memory devices can be implemented simply by using a patterning technique using a solution process. In this study, a flexible NiO ReRAM device was fabricated using a simple NC patterning method that controls the capillary force and dewetting of a NiO NC solution at low temperature. The switching behavior of a NiO NC based memory was clearly observed by conductive atomic force microscopy (c-AFM).

Nanoalloy Printed and Pulse-Laser Sintered Flexible Sensor Devices with Enhanced Stability and Materials Compatibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Wei; Rovore, Thomas; Weerawarne, Darshana

2015-06-02

While conformal and wearable devices have become one of the most desired formats for printable electronics, it is challenging to establish a scalable process that produces stable conductive patterns but also uses substrates compatible with widely available wearable materials. Here, we describe findings of an investigation of a nanoalloy ink printed and pulsed laser sintered conductive patterns as flexible functional devices with enhanced stability and materials compatibility. While nanoparticle inks are desired for printable electronics, almost all existing nanoparticle inks are based on single-metal component, which, as an electronic element, is limited by its inherent stabilities of the metal suchmore » as propensity of metal oxidation and mobility of metal ions, especially in sintering processes. The work here has demonstrated the first example in exploiting plasmonic coupling of nanoalloys and pulsed-laser energy with controllable thermal penetration. The experimental and theoretical results have revealed clear correlation between the pulsed laser parameters and the nanoalloy structural characteristics. The superior performance of the resulting flexible sensor device, upon imparting nanostructured sensing materials, for detecting volatile organic compounds has significant implications to developing stable and wearable sensors for monitoring environmental pollutants and breath biomarkers. This simple “nanoalloy printing 'laser sintering' nanostructure printing” process is entirely general to many different sensor devices and nanostructured sensing materials, enabling the ability to easily construct sophisticated sensor array.« less

Printed Flexible Plastic Microchip for Viral Load Measurement through Quantitative Detection of Viruses in Plasma and Saliva

PubMed Central

Shafiee, Hadi; Kanakasabapathy, Manoj Kumar; Juillard, Franceline; Keser, Mert; Sadasivam, Magesh; Yuksekkaya, Mehmet; Hanhauser, Emily; Henrich, Timothy J.; Kuritzkes, Daniel R.; Kaye, Kenneth M.; Demirci, Utkan

2015-01-01

We report a biosensing platform for viral load measurement through electrical sensing of viruses on a flexible plastic microchip with printed electrodes. Point-of-care (POC) viral load measurement is of paramount importance with significant impact on a broad range of applications, including infectious disease diagnostics and treatment monitoring specifically in resource-constrained settings. Here, we present a broadly applicable and inexpensive biosensing technology for accurate quantification of bioagents, including viruses in biological samples, such as plasma and artificial saliva, at clinically relevant concentrations. Our microchip fabrication is simple and mass-producible as we print microelectrodes on flexible plastic substrates using conductive inks. We evaluated the microchip technology by detecting and quantifying multiple Human Immunodeficiency Virus (HIV) subtypes (A, B, C, D, E, G, and panel), Epstein-Barr Virus (EBV), and Kaposi’s Sarcoma-associated Herpes Virus (KSHV) in a fingerprick volume (50 µL) of PBS, plasma, and artificial saliva samples for a broad range of virus concentrations between 102 copies/mL and 107 copies/mL. We have also evaluated the microchip platform with discarded, de-identified HIV-infected patient samples by comparing our microchip viral load measurement results with reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) as the gold standard method using Bland-Altman Analysis. PMID:26046668

An Ag-grid/graphene hybrid structure for large-scale, transparent, flexible heaters.

PubMed

Kang, Junmo; Jang, Yonghee; Kim, Youngsoo; Cho, Seung-Hyun; Suhr, Jonghwan; Hong, Byung Hee; Choi, Jae-Boong; Byun, Doyoung

2015-04-21

Recently, carbon materials such as carbon nanotubes and graphene have been proposed as alternatives to indium tin oxide (ITO) for fabricating transparent conducting materials. However, obtaining low sheet resistance and high transmittance of these carbon materials has been challenging due to the intrinsic properties of the materials. In this paper, we introduce highly transparent and flexible conductive films based on a hybrid structure of graphene and an Ag-grid. Electrohydrodynamic (EHD) jet printing was used to produce a micro-scale grid consisting of Ag lines less than 10 μm wide. We were able to directly write the Ag-grid on a large-area graphene/flexible substrate due to the high conductivity of graphene. The hybrid electrode could be fabricated using hot pressing transfer and EHD jet printing in a non-vacuum, maskless, and low-temperature environment. The hybrid electrode offers an effective and simple route for achieving a sheet resistance as low as ∼4 Ω per square with ∼78% optical transmittance. Finally, we demonstrate that transparent flexible heaters based on the hybrid conductive films could be used in a vehicle or a smart window system.

Subliminal encoding and flexible retrieval of objects in scenes.

PubMed

Wuethrich, Sergej; Hannula, Deborah E; Mast, Fred W; Henke, Katharina

2018-04-27

Our episodic memory stores what happened when and where in life. Episodic memory requires the rapid formation and flexible retrieval of where things are located in space. Consciousness of the encoding scene is considered crucial for episodic memory formation. Here, we question the necessity of consciousness and hypothesize that humans can form unconscious episodic memories. Participants were presented with subliminal scenes, i.e., scenes invisible to the conscious mind. The scenes displayed objects at certain locations for participants to form unconscious object-in-space memories. Later, the same scenes were presented supraliminally, i.e., visibly, for retrieval testing. Scenes were presented absent the objects and rotated by 90°-270° in perspective to assess the representational flexibility of unconsciously formed memories. During the test phase, participants performed a forced-choice task that required them to place an object in one of two highlighted scene locations and their eye movements were recorded. Evaluation of the eye tracking data revealed that participants remembered object locations unconsciously, irrespective of changes in viewing perspective. This effect of gaze was related to correct placements of objects in scenes, and an intuitive decision style was necessary for unconscious memories to influence intentional behavior to a significant degree. We conclude that conscious perception is not mandatory for spatial episodic memory formation. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Fully Printed High-Frequency Phased-Array Antenna on Flexible Substrate

NASA Technical Reports Server (NTRS)

Chen, Yihong; Lu, Xuejun

2010-01-01

To address the issues of flexible electronics needed for surface-to-surface, surface-to-orbit, and back-to-Earth communications necessary for manned exploration of the Moon, Mars, and beyond, a room-temperature printing process has been developed to create active, phased-array antennas (PAAs) on a flexible Kapton substrate. Field effect transistors (FETs) based on carbon nanotubes (CNTs), with many unique physical properties, were successfully proven feasible for phased-array antenna systems. The carrier mobility of an individual CNT is estimated to be at least 100,000 sq cm/V(dot)s. The CNT network in solution has carrier mobility as high as 46,770 sq cm/V(dot)s, and has a large current-density carrying capacity of approx. 1,000 mA/sq cm , which corresponds to a high carrying power of over 2,000 mW/ sq cm. Such high carrier mobility, and large current carrying capacity, allows the achievement of high-speed (>100 GHz), high-power, flexible electronic circuits that can be monolithically integrated on NASA s active phasedarray antennas for various applications, such as pressurized rovers, pressurized habitats, and spacesuits, as well as for locating beacon towers for lunar surface navigation, which will likely be performed at S-band and attached to a mobile astronaut. A fully printed 2-bit 2-element phasedarray antenna (PAA) working at 5.6 GHz, incorporating the CNT FETs as phase shifters, is demonstrated. The PAA is printed out at room temperature on 100-mm thick Kapton substrate. Four CNT FETs are printed together with microstrip time delay lines to function as a 2-bit phase shifter. The FET switch exhibits a switching speed of 0.2 ns, and works well for a 5.6-GHz RF signal. The operating frequency is measured to be 5.6 GHz, versus the state-of-the-art flexible FET operating frequency of 52 MHz. The source-drain current density is measured to be over 1,000 mA/sq cm, while the conventional organic FETs, and single carbon nanotube-based FETs, are typically in the mA to mA/sq cm range. The switching voltage used is 1.8 V, while the state-of-the-art flexible FET has a gate voltage around 50 V. The gate voltage can effectively control the source-drain current with an ON-OFF ratio of over 1,000 obtained at a low Vds bias of 1.8 V. The azimuth steering angles of PAA are measured at 0deg, -14.5deg, -30deg, and 48.6deg. The measured far-field patterns agree well with simulation results. The efficiency of the 2-bit 2-element PAA is measured to be 39 percent, including the loss of transmission line, FET switch, and coupling loss of RF probes. With further optimization, the efficiency is expected to be around 50-60 percent.

Individual Differences in the Development of Early Writing Skills: Testing the Unique Contribution of Visuo-Spatial Working Memory

ERIC Educational Resources Information Center

Bourke, Lorna; Davies, Simon J.; Sumner, Emma; Green, Carolyn

2014-01-01

Visually mediated processes including, exposure to print (e.g. reading) as well as orthographic transcription and coding skills, have been found to contribute to individual differences in literacy development. The current study examined the role of visuospatial working memory (WM) in underpinning this relationship and emergent writing. One hundred…

A bill to designate the Liberty Memorial at the National World War I Museum in Kansas City, Missouri, as the "National World War I Memorial".

THOMAS, 111th Congress

Sen. McCaskill, Claire [D-MO

2009-04-01

Senate - 12/03/2009 Committee on Energy and Natural Resources Subcommittee on National Parks. Hearings held. With printed Hearing: S.Hrg. 111-318. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Time limits during visual foraging reveal flexible working memory templates.

PubMed

Kristjánsson, Tómas; Thornton, Ian M; Kristjánsson, Árni

2018-06-01

During difficult foraging tasks, humans rarely switch between target categories, but switch frequently during easier foraging. Does this reflect fundamental limits on visual working memory (VWM) capacity or simply strategic choice due to effort? Our participants performed time-limited or unlimited foraging tasks where they tapped stimuli from 2 target categories while avoiding items from 2 distractor categories. These time limits should have no effect if capacity imposes limits on VWM representations but more flexible VWM could allow observers to use VWM according to task demands in each case. We found that with time limits, participants switched more frequently and switch-costs became much smaller than during unlimited foraging. Observers can therefore switch between complex (conjunction) target categories when needed. We propose that while maintaining many complex templates in working memory is effortful and observers avoid this, they can do so if this fits task demands, showing the flexibility of working memory representations used for visual exploration. This is in contrast with recent proposals, and we discuss the implications of these findings for theoretical accounts of working memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Fabrication of ultra-fine nanostructures using edge transfer printing.

PubMed

Xue, Mianqi; Li, Fengwang; Cao, Tingbing

2012-03-21

The exploration of new methods and techniques for application in diverse fields, such as photonics, microfluidics, biotechnology and flexible electronics is of increasing scientific and technical interest for multiple uses over distance of 10-100 nm. This article discusses edge transfer printing--a series of unconventional methods derived from soft lithography for nanofabrication. It possesses the advantages of easy fabrication, low-cost and great serviceability. In this paper, we show how to produce exposed edges and use various materials for edge transfer printing, while nanoskiving, nanotransfer edge printing and tunable cracking for nanogaps are introduced. Besides this, different functional materials, such as metals, inorganic semiconductors and polymers, as well as localised heating and charge patterning, are described here as unconventional "inks" for printing. Edge transfer printing, which can effectively produce sub-100 nm scale ultra-fine structures, has broad applications, including metallic nanowires as nanoelectrodes, semiconductor nanowires for chemical sensors, heterostructures of organic semiconductors, plasmonic devices and so forth. This journal is © The Royal Society of Chemistry 2012

Fabrication of a Flexible Amperometric Glucose Sensor Using Additive Processes

PubMed Central

Du, Xiaosong; Durgan, Christopher J.; Matthews, David J.; Motley, Joshua R.; Tan, Xuebin; Pholsena, Kovit; Árnadóttir, Líney; Castle, Jessica R.; Jacobs, Peter G.; Cargill, Robert S.; Ward, W. Kenneth; Conley, John F.; Herman, Gregory S.

2015-01-01

This study details the use of printing and other additive processes to fabricate a novel amperometric glucose sensor. The sensor was fabricated using a Au coated 12.7 μm thick polyimide substrate as a starting material, where micro-contact printing, electrochemical plating, chloridization, electrohydrodynamic jet (e-jet) printing, and spin coating were used to pattern, deposit, chloridize, print, and coat functional materials, respectively. We have found that e-jet printing was effective for the deposition and patterning of glucose oxidase inks with lateral feature sizes between ~5 to 1000 μm in width, and that the glucose oxidase was still active after printing. The thickness of the permselective layer was optimized to obtain a linear response for glucose concentrations up to 32 mM and no response to acetaminophen, a common interfering compound, was observed. The use of such thin polyimide substrates allow wrapping of the sensors around catheters with high radius of curvature ~250 μm, where additive and microfabrication methods may allow significant cost reductions. PMID:26634186

Design and Structure-Function Characterization of 3D Printed Synthetic Porous Biomaterials for Tissue Engineering.

PubMed

Kelly, Cambre N; Miller, Andrew T; Hollister, Scott J; Guldberg, Robert E; Gall, Ken

2018-04-01

3D printing is now adopted for use in a variety of industries and functions. In biomedical engineering, 3D printing has prevailed over more traditional manufacturing methods in tissue engineering due to its high degree of control over both macro- and microarchitecture of porous tissue scaffolds. However, with the improved flexibility in design come new challenges in characterizing the structure-function relationships between various architectures and both mechanical and biological properties in an assortment of clinical applications. Presently, the field of tissue engineering lacks a comprehensive body of literature that is capable of drawing meaningful relationships between the designed structure and resulting function of 3D printed porous biomaterial scaffolds. This work first discusses the role of design on 3D printed porous scaffold function and then reviews characterization of these structure-function relationships for 3D printed synthetic metallic, polymeric, and ceramic biomaterials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct selective growth of ZnO nanowire arrays from inkjet-printed zinc acetate precursor on a heated substrate

PubMed Central

2013-01-01

Inkjet printing of functional materials has drawn tremendous interest as an alternative to the conventional photolithography-based microelectronics fabrication process development. We introduce direct selective nanowire array growth by inkjet printing of Zn acetate precursor ink patterning and subsequent hydrothermal ZnO local growth without nozzle clogging problem which frequently happens in nanoparticle inkjet printing. The proposed process can directly grow ZnO nanowires in any arbitrary patterned shape, and it is basically very fast, low cost, environmentally benign, and low temperature. Therefore, Zn acetate precursor inkjet printing-based direct nanowire local growth is expected to give extremely high flexibility in nanomaterial patterning for high-performance electronics fabrication especially at the development stage. As a proof of concept of the proposed method, ZnO nanowire network-based field effect transistors and ultraviolet photo-detectors were demonstrated by direct patterned grown ZnO nanowires as active layer. PMID:24252130

Fabrication of terahertz metamaterials using electrohydrodynamic jet printing for sensitive detection of yeast

NASA Astrophysics Data System (ADS)

Pradhipta Tenggara, Ayodya; Park, S. J.; Teguh Yudistira, Hadi; Ahn, Y. H.; Byun, Doyoung

2017-03-01

We demonstrated the fabrication of terahertz metamaterial sensor for the accurate and on-site detection of yeast using electrohydrodynamic jet printing, which is inexpensive, simple, and environmentally friendly. The very small sized pattern up to 5 µm-width of electrical split ring resonator unit structures could be printed on a large area on both a rigid substrate and flexible substrate, i.e. silicon wafer and polyimide film using the drop on demand technique to eject liquid ink containing silver nanoparticles. Experimental characterization and simulation were performed to study their performances in detecting yeast of different weights. It was shown that the metamaterial sensor fabricated on a flexible polyimide film had higher sensitivity by more than six times than the metamaterial sensor fabricated on a silicon wafer, due to the low refractive index of the PI substrate and due to the extremely thin substrate thickness which lowers the effective index further. The resonance frequency shift saturated when the yeast weights were 145 µg and 215 µg for metamaterial structures with gap size 6.5 µm fabricated on the silicon substrate and on the polyimide substrate, respectively.

A Printed Xi-Shaped Left-Handed Metamaterial on Low-Cost Flexible Photo Paper.

PubMed

Ashraf, Farhad Bin; Alam, Touhidul; Islam, Mohammad Tariqul

2017-07-05

A Xi-shaped meta structure, has been introduced in this paper. A modified split-ring resonator (MSRR) and a capacitive loaded strip (CLS) were used to achieve the left-handed property of the metamaterial. The structure was printed using silver metallic nanoparticle ink, using a very low-cost photo paper as a substrate material. Resonators were inkjet-printed using silver nanoparticle metallic ink on paper to make this metamaterial flexible. It is also free from any kind of chemical waste, which makes it eco-friendly. A double negative region from 8.72 GHz to 10.91 GHz (bandwidth of 2.19 GHz) in the X-band microwave spectra was been found. Figure of merit was also obtained to measure any loss in the double negative region. The simulated result was verified by the performance of the fabricated prototype. The total dimensions of the proposed structure were 0.29 λ × 0.29 λ × 0.007 λ . It is a promising unit cell because of its simplicity, cost-effectiveness, and easy fabrication process.

A Consecutive Spray Printing Strategy to Construct and Integrate Diverse Supercapacitors on Various Substrates.

PubMed

Wang, Xinyu; Lu, Qiongqiong; Chen, Chen; Han, Mo; Wang, Qingrong; Li, Haixia; Niu, Zhiqiang; Chen, Jun

2017-08-30

The rapid development of printable electronic devices with flexible and wearable characteristics requires supercapacitor devices to be printable, light, thin, integrated macro- and micro-devices with flexibility. Herein, we developed a consecutive spray printing strategy to controllably construct and integrate diverse supercapacitors on various substrates. In such a strategy, all supercapacitor components are fully printable, and their thicknesses and shapes are well controlled. As a result, supercapacitors obtained by this strategy achieve diverse structures and shapes. In addition, different nanocarbon and pseudocapacitive materials are applicable for the fabrication of these diverse supercapacitors. Furthermore, the diverse supercapacitors can be readily constructed on various objects with planar, curved, or even rough surfaces (e.g., plastic film, glass, cloth, and paper). More importantly, the consecutive spray printing process can integrate several supercapacitors together in the perpendicular and parallel directions of one substrate by designing the structure of electrodes and separators. This enlightens the construction and integration of fully printable supercapacitors with diverse configurations to be compatible with fully printable electronics on various substrates.

Spider-web inspired multi-resolution graphene tactile sensor.

PubMed

Liu, Lu; Huang, Yu; Li, Fengyu; Ma, Ying; Li, Wenbo; Su, Meng; Qian, Xin; Ren, Wanjie; Tang, Kanglai; Song, Yanlin

2018-05-08

Multi-dimensional accurate response and smooth signal transmission are critical challenges in the advancement of multi-resolution recognition and complex environment analysis. Inspired by the structure-activity relationship between discrepant microstructures of the spiral and radial threads in a spider web, we designed and printed graphene with porous and densely-packed microstructures to integrate into a multi-resolution graphene tactile sensor. The three-dimensional (3D) porous graphene structure performs multi-dimensional deformation responses. The laminar densely-packed graphene structure contributes excellent conductivity with flexible stability. The spider-web inspired printed pattern inherits orientational and locational kinesis tracking. The multi-structure construction with homo-graphene material can integrate discrepant electronic properties with remarkable flexibility, which will attract enormous attention for electronic skin, wearable devices and human-machine interactions.

3D Printing by Multiphase Silicone/Water Capillary Inks.

PubMed

Roh, Sangchul; Parekh, Dishit P; Bharti, Bhuvnesh; Stoyanov, Simeon D; Velev, Orlin D

2017-08-01

3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frontotemporal Functional Connectivity and Executive Functions Contribute to Episodic Memory Performance

PubMed Central

Blankenship, Tashauna L.; O'Neill, Meagan; Deater-Deckard, Kirby; Diana, Rachel A.; Bell, Martha Ann

2016-01-01

The contributions of hemispheric-specific electrophysiology (electroencephalogram or EEG) and independent executive functions (inhibitory control, working memory, cognitive flexibility) to episodic memory performance were examined using abstract paintings. Right hemisphere frontotemporal functional connectivity during encoding and retrieval, measured via EEG alpha coherence, statistically predicted performance on recency but not recognition judgments for the abstract paintings. Theta coherence, however, did not predict performance. Likewise, cognitive flexibility statistically predicted performance on recency judgments, but not recognition. These findings suggest that recognition and recency operate via separate electrophysiological and executive mechanisms. PMID:27388478

Patterned surface with controllable wettability for inkjet printing of flexible printed electronics.

PubMed

Nguyen, Phuong Q M; Yeo, Lip-Pin; Lok, Boon-Keng; Lam, Yee-Cheong

2014-03-26

Appropriate control of substrate surface properties prior to inkjet printing could be employed to improve the printing quality of fine resolution structures. In this paper, novel methods to fabricate patterned surfaces with a combination of hydrophilic and hydrophobic properties are investigated. The results of inkjet printing of PEDOT/PSS conductive ink on these modified surfaces are presented. Selective wetting was achieved via a two-step hydrophilic-hydrophobic coating of 3-aminopropyl trimethoxysilane (APTMS) and 3M electronic grade chemical respectively on PET surfaces; this was followed by a selective hydrophilic treatment (either atmospheric O2/Ar plasma or UV/ozone surface treatment) with the aid of a Nickel stencil. Hydrophobic regions with water contact angle (WCA) of 105° and superhydrophilic regions with WCA <5° can be achieved on a single surface. During inkjet printing of the treated surfaces, PEDOT/PSS ink spread spontaneously along the hydrophilic areas while avoiding the hydrophobic regions. Fine features smaller than the inkjet droplet size (approximately 55 μm in diameter) can be successfully printed on the patterned surface with high wettability contrast.

Four-Dimensional Printing Hierarchy Scaffolds with Highly Biocompatible Smart Polymers for Tissue Engineering Applications

PubMed Central

Miao, Shida; Zhu, Wei; Castro, Nathan J.; Leng, Jinsong

2016-01-01

The objective of this study was to four-dimensional (4D) print novel biomimetic gradient tissue scaffolds with highly biocompatible naturally derived smart polymers. The term “4D printing” refers to the inherent smart shape transformation of fabricated constructs when implanted minimally invasively for seamless and dynamic integration. For this purpose, a series of novel shape memory polymers with excellent biocompatibility and tunable shape changing effects were synthesized and cured in the presence of three-dimensional printed sacrificial molds, which were subsequently dissolved to create controllable and graded porosity within the scaffold. Surface morphology, thermal, mechanical, and biocompatible properties as well as shape memory effects of the synthesized smart polymers and resultant porous scaffolds were characterized. Fourier transform infrared spectroscopy and gel content analysis confirmed the formation of chemical crosslinking by reacting polycaprolactone triol and castor oil with multi-isocyanate groups. Differential scanning calorimetry revealed an adjustable glass transition temperature in a range from −8°C to 35°C. Uniaxial compression testing indicated that the obtained polymers, possessing a highly crosslinked interpenetrating polymeric networks, have similar compressive modulus to polycaprolactone. Shape memory tests revealed that the smart polymers display finely tunable recovery speed and exhibit greater than 92% shape fixing at −18°C or 0°C and full shape recovery at physiological temperature. Scanning electron microscopy analysis of fabricated scaffolds revealed a graded microporous structure, which mimics the nonuniform distribution of porosity found within natural tissues. With polycaprolactone serving as a control, human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and differentiation greatly increased on our novel smart polymers. The current work will significantly advance the future design and development of novel and functional biomedical scaffolds with advanced 4D printing technology and highly biocompatible smart biomaterials. PMID:28195832

Biomimetic 3D tissue printing for soft tissue regeneration.

PubMed

Pati, Falguni; Ha, Dong-Heon; Jang, Jinah; Han, Hyun Ho; Rhie, Jong-Won; Cho, Dong-Woo

2015-09-01

Engineered adipose tissue constructs that are capable of reconstructing soft tissue with adequate volume would be worthwhile in plastic and reconstructive surgery. Tissue printing offers the possibility of fabricating anatomically relevant tissue constructs by delivering suitable matrix materials and living cells. Here, we devise a biomimetic approach for printing adipose tissue constructs employing decellularized adipose tissue (DAT) matrix bioink encapsulating human adipose tissue-derived mesenchymal stem cells (hASCs). We designed and printed precisely-defined and flexible dome-shaped structures with engineered porosity using DAT bioink that facilitated high cell viability over 2 weeks and induced expression of standard adipogenic genes without any supplemented adipogenic factors. The printed DAT constructs expressed adipogenic genes more intensely than did non-printed DAT gel. To evaluate the efficacy of our printed tissue constructs for adipose tissue regeneration, we implanted them subcutaneously in mice. The constructs did not induce chronic inflammation or cytotoxicity postimplantation, but supported positive tissue infiltration, constructive tissue remodeling, and adipose tissue formation. This study demonstrates that direct printing of spatially on-demand customized tissue analogs is a promising approach to soft tissue regeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Printed organo-functionalized graphene for biosensing applications.

PubMed

Wisitsoraat, A; Mensing, J Ph; Karuwan, C; Sriprachuabwong, C; Jaruwongrungsee, K; Phokharatkul, D; Daniels, T M; Liewhiran, C; Tuantranont, A

2017-01-15

Graphene is a highly promising material for biosensors due to its excellent physical and chemical properties which facilitate electron transfer between the active locales of enzymes or other biomaterials and a transducer surface. Printing technology has recently emerged as a low-cost and practical method for fabrication of flexible and disposable electronics devices. The combination of these technologies is promising for the production and commercialization of low cost sensors. In this review, recent developments in organo-functionalized graphene and printed biosensor technologies are comprehensively covered. Firstly, various methods for printing graphene-based fluids on different substrates are discussed. Secondly, different graphene-based ink materials and preparation methods are described. Lastly, biosensing performances of printed or printable graphene-based electrochemical and field effect transistor sensors for some important analytes are elaborated. The reported printed graphene based sensors exhibit promising properties with good reliability suitable for commercial applications. Among most reports, only a few printed graphene-based biosensors including screen-printed oxidase-functionalized graphene biosensor have been demonstrated. The technology is still at early stage but rapidly growing and will earn great attention in the near future due to increasing demand of low-cost and disposable biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitra, Kalyan Yoti, E-mail: kalyan-yoti.mitra@mb.tu-chemnitz.de, E-mail: enrico.sowade@mb.tu-chemnitz.de; Sowade, Enrico, E-mail: kalyan-yoti.mitra@mb.tu-chemnitz.de, E-mail: enrico.sowade@mb.tu-chemnitz.de; Martínez-Domingo, Carme

Inkjet Technology is often mis-believed to be a deposition/patterning technology which is not meant for high fabrication throughput in the field of printed and flexible electronics. In this work, we report on the 1) printing, 2) fabrication yield and 3) characterization of exemplary simple devices e.g. capacitors, organic transistors etc. which are the basic building blocks for logical circuits. For this purpose, printing is performed first with a Proof of concept Inkjet printing system Dimatix Material Printer 2831 (DMP 2831) using 10 pL small print-heads and then with Dimatix Material Printer 3000 (DMP 3000) using 35 pL industrial print-heads (frommore » Fujifilm Dimatix). Printing at DMP 3000 using industrial print-heads (in Sheet-to-sheet) paves the path towards industrialization which can be defined by printing in Roll-to-Roll format using industrial print-heads. This pavement can be termed as 'Bridging Platform'. This transfer to 'Bridging Platform' from 10 pL small print-heads to 35 pL industrial print-heads help the inkjet-printed devices to evolve on the basis of functionality and also in form of up-scaled quantities. The high printed quantities and yield of inkjet-printed devices justify the deposition reliability and potential to print circuits. This reliability is very much desired when it comes to printing of circuits e.g. inverters, ring oscillator and any other planned complex logical circuits which require devices e.g. organic transistors which needs to get connected in different staged levels. Also, the up-scaled inkjet-printed devices are characterized and they reflect a domain under which they can work to their optimal status. This status is much wanted for predicting the real device functionality and integration of them into a planned circuit.« less

Development of Oromucosal Dosage Forms by Combining Electrospinning and Inkjet Printing.

PubMed

Palo, Mirja; Kogermann, Karin; Laidmäe, Ivo; Meos, Andres; Preis, Maren; Heinämäki, Jyrki; Sandler, Niklas

2017-03-06

Printing technology has been shown to enable flexible fabrication of solid dosage forms for personalized drug therapy. Several methods can be applied for tailoring the properties of the printed pharmaceuticals. In this study, the use of electrospun fibrous substrates in the fabrication of inkjet-printed dosage forms was investigated. A single-drug formulation with lidocaine hydrochloride (LH) and a combination drug system containing LH and piroxicam (PRX) for oromucosal administration were prepared. The LH was deposited on the electrospun and cross-linked gelatin substrates by inkjet printing, whereas PRX was incorporated within the substrate fibers during electrospinning. The solid state analysis of the electrospun substrates showed that PRX was in an amorphous state within the fibers. Furthermore, the results indicated the entrapment and solidification of the dissolved LH within the fibrous gelatin matrix. The printed drug amount (2-3 mg) was in good correlation with the theoretical dose calculated based on the printing parameters. However, a noticeable degradation of the printed LH was detected after a few months. An immediate release (over 85% drug release after 8 min) of both drugs from the printed dosage forms was observed. In conclusion, the prepared electrospun gelatin scaffolds were shown to be suitable substrates for inkjet printing of oromucosal formulations. The combination of electrospinning and inkjet printing allowed the preparation of a dual drug system.

Epitaxial Growth of Thin Ferroelectric Polymer Films on Graphene Layer for Fully Transparent and Flexible Nonvolatile Memory.

PubMed

Kim, Kang Lib; Lee, Wonho; Hwang, Sun Kak; Joo, Se Hun; Cho, Suk Man; Song, Giyoung; Cho, Sung Hwan; Jeong, Beomjin; Hwang, Ihn; Ahn, Jong-Hyun; Yu, Young-Jun; Shin, Tae Joo; Kwak, Sang Kyu; Kang, Seok Ju; Park, Cheolmin

2016-01-13

Enhancing the device performance of organic memory devices while providing high optical transparency and mechanical flexibility requires an optimized combination of functional materials and smart device architecture design. However, it remains a great challenge to realize fully functional transparent and mechanically durable nonvolatile memory because of the limitations of conventional rigid, opaque metal electrodes. Here, we demonstrate ferroelectric nonvolatile memory devices that use graphene electrodes as the epitaxial growth substrate for crystalline poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) polymer. The strong crystallographic interaction between PVDF-TrFE and graphene results in the orientation of the crystals with distinct symmetry, which is favorable for polarization switching upon the electric field. The epitaxial growth of PVDF-TrFE on a graphene layer thus provides excellent ferroelectric performance with high remnant polarization in metal/ferroelectric polymer/metal devices. Furthermore, a fully transparent and flexible array of ferroelectric field effect transistors was successfully realized by adopting transparent poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] semiconducting polymer.

Large-area, flexible imaging arrays constructed by light-charge organic memories

PubMed Central

Zhang, Lei; Wu, Ti; Guo, Yunlong; Zhao, Yan; Sun, Xiangnan; Wen, Yugeng; Yu, Gui; Liu, Yunqi

2013-01-01

Existing organic imaging circuits, which offer attractive benefits of light weight, low cost and flexibility, are exclusively based on phototransistor or photodiode arrays. One shortcoming of these photo-sensors is that the light signal should keep invariant throughout the whole pixel-addressing and reading process. As a feasible solution, we synthesized a new charge storage molecule and embedded it into a device, which we call light-charge organic memory (LCOM). In LCOM, the functionalities of photo-sensor and non-volatile memory are integrated. Thanks to the deliberate engineering of electronic structure and self-organization process at the interface, 92% of the stored charges, which are linearly controlled by the quantity of light, retain after 20000 s. The stored charges can also be non-destructively read and erased by a simple voltage program. These results pave the way to large-area, flexible imaging circuits and demonstrate a bright future of small molecular materials in non-volatile memory. PMID:23326636

The Development and Use of Memory Strategies by Deaf Children and Adults.

ERIC Educational Resources Information Center

Liben, Lynn S.

The availability and application of particular memory strategies by deaf children and adults was examined. In the first study, 20 younger (mean age, 6 years, 3 months) and 20 older (8 years, 8 months) children's use of rehearsal strategies was examined with a serial probe task. All four types of stimuli (animals, nonsense shapes, hands, print)…

A Study of the Effect of Color in Memory Retention When Used in Presentation Software.

ERIC Educational Resources Information Center

McConnohie, Bruce Vernon

A study of the effects of color as used in presentation software on short-range (immediately following treatment) and long-range (one hour following treatment) memory retention was conducted. Previous studies have concentrated on color as cueing or coding mechanisms primarily in print media and have not explored the effect of individual colors as…

High-Performance Flexible Organic Nano-Floating Gate Memory Devices Functionalized with Cobalt Ferrite Nanoparticles.

PubMed

Jung, Ji Hyung; Kim, Sunghwan; Kim, Hyeonjung; Park, Jongnam; Oh, Joon Hak

2015-10-07

Nano-floating gate memory (NFGM) devices are transistor-type memory devices that use nanostructured materials as charge trap sites. They have recently attracted a great deal of attention due to their excellent performance, capability for multilevel programming, and suitability as platforms for integrated circuits. Herein, novel NFGM devices have been fabricated using semiconducting cobalt ferrite (CoFe2O4) nanoparticles (NPs) as charge trap sites and pentacene as a p-type semiconductor. Monodisperse CoFe2O4 NPs with different diameters have been synthesized by thermal decomposition and embedded in NFGM devices. The particle size effects on the memory performance have been investigated in terms of energy levels and particle-particle interactions. CoFe2O4 NP-based memory devices exhibit a large memory window (≈73.84 V), a high read current on/off ratio (read I(on)/I(off)) of ≈2.98 × 10(3), and excellent data retention. Fast switching behaviors are observed due to the exceptional charge trapping/release capability of CoFe2O4 NPs surrounded by the oleate layer, which acts as an alternative tunneling dielectric layer and simplifies the device fabrication process. Furthermore, the NFGM devices show excellent thermal stability, and flexible memory devices fabricated on plastic substrates exhibit remarkable mechanical and electrical stability. This study demonstrates a viable means of fabricating highly flexible, high-performance organic memory devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3D printing and intraoperative neuronavigation tailoring for skull base reconstruction after extended endoscopic endonasal surgery: proof of concept.

PubMed

Essayed, Walid I; Unadkat, Prashin; Hosny, Ahmed; Frisken, Sarah; Rassi, Marcio S; Mukundan, Srinivasan; Weaver, James C; Al-Mefty, Ossama; Golby, Alexandra J; Dunn, Ian F

2018-03-02

OBJECTIVE Endoscopic endonasal approaches are increasingly performed for the surgical treatment of multiple skull base pathologies. Preventing postoperative CSF leaks remains a major challenge, particularly in extended approaches. In this study, the authors assessed the potential use of modern multimaterial 3D printing and neuronavigation to help model these extended defects and develop specifically tailored prostheses for reconstructive purposes. METHODS Extended endoscopic endonasal skull base approaches were performed on 3 human cadaveric heads. Preprocedure and intraprocedure CT scans were completed and were used to segment and design extended and tailored skull base models. Multimaterial models with different core/edge interfaces were 3D printed for implantation trials. A novel application of the intraoperative landmark acquisition method was used to transfer the navigation, helping to tailor the extended models. RESULTS Prostheses were created based on preoperative and intraoperative CT scans. The navigation transfer offered sufficiently accurate data to tailor the preprinted extended skull base defect prostheses. Successful implantation of the skull base prostheses was achieved in all specimens. The progressive flexibility gradient of the models' edges offered the best compromise for easy intranasal maneuverability, anchoring, and structural stability. Prostheses printed based on intraprocedure CT scans were accurate in shape but slightly undersized. CONCLUSIONS Preoperative 3D printing of patient-specific skull base models is achievable for extended endoscopic endonasal surgery. The careful spatial modeling and the use of a flexibility gradient in the design helped achieve the most stable reconstruction. Neuronavigation can help tailor preprinted prostheses.

Precision of synesthetic color matching resembles that for recollected colors rather than physical colors.

PubMed

Arnold, Derek H; Wegener, Signy V; Brown, Francesca; Mattingley, Jason B

2012-10-01

Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but hearing the name of a grapheme does not. This dissociation allowed us to compare the precision with which synesthetes are able to match their color experiences triggered by visible graphemes, with the precision of their matches for recalled colors based on the same graphemes spoken aloud. In six synesthetes, color matching for printed graphemes was equally variable relative to recalled experiences. In a control experiment, synesthetes and age-matched controls either matched the color of a circular patch while it was visible on a screen, or they judged its color from memory after it had disappeared. Both synesthetes and controls were more variable when matching from memory, and the variance of synesthetes' recalled color judgments matched that associated with their synesthetic judgments for visible graphemes in the first experiment. Results suggest that synesthetic experiences of color triggered by achromatic graphemes are analogous to recollections of color.

Toward printed integrated circuits based on unipolar or ambipolar polymer semiconductors.

PubMed

Baeg, Kang-Jun; Caironi, Mario; Noh, Yong-Young

2013-08-21

For at least the past ten years printed electronics has promised to revolutionize our daily life by making cost-effective electronic circuits and sensors available through mass production techniques, for their ubiquitous applications in wearable components, rollable and conformable devices, and point-of-care applications. While passive components, such as conductors, resistors and capacitors, had already been fabricated by printing techniques at industrial scale, printing processes have been struggling to meet the requirements for mass-produced electronics and optoelectronics applications despite their great potential. In the case of logic integrated circuits (ICs), which constitute the focus of this Progress Report, the main limitations have been represented by the need of suitable functional inks, mainly high-mobility printable semiconductors and low sintering temperature conducting inks, and evoluted printing tools capable of higher resolution, registration and uniformity than needed in the conventional graphic arts printing sector. Solution-processable polymeric semiconductors are the best candidates to fulfill the requirements for printed logic ICs on flexible substrates, due to their superior processability, ease of tuning of their rheology parameters, and mechanical properties. One of the strongest limitations has been mainly represented by the low charge carrier mobility (μ) achievable with polymeric, organic field-effect transistors (OFETs). However, recently unprecedented values of μ ∼ 10 cm(2) /Vs have been achieved with solution-processed polymer based OFETs, a value competing with mobilities reported in organic single-crystals and exceeding the performances enabled by amorphous silicon (a-Si). Interestingly these values were achieved thanks to the design and synthesis of donor-acceptor copolymers, showing limited degree of order when processed in thin films and therefore fostering further studies on the reason leading to such improved charge transport properties. Among this class of materials, various polymers can show well balanced electrons and holes mobility, therefore being indicated as ambipolar semiconductors, good environmental stability, and a small band-gap, which simplifies the tuning of charge injection. This opened up the possibility of taking advantage of the superior performances offered by complementary "CMOS-like" logic for the design of digital ICs, easing the scaling down of critical geometrical features, and achieving higher complexity from robust single gates (e.g., inverters) and test circuits (e.g., ring oscillators) to more complete circuits. Here, we review the recent progress in the development of printed ICs based on polymeric semiconductors suitable for large-volume micro- and nano-electronics applications. Particular attention is paid to the strategies proposed in the literature to design and synthesize high mobility polymers and to develop suitable printing tools and techniques to allow for improved patterning capability required for the down-scaling of devices in order to achieve the operation frequencies needed for applications, such as flexible radio-frequency identification (RFID) tags, near-field communication (NFC) devices, ambient electronics, and portable flexible displays. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new chapter in pharmaceutical manufacturing: 3D-printed drug products.

PubMed

Norman, James; Madurawe, Rapti D; Moore, Christine M V; Khan, Mansoor A; Khairuzzaman, Akm

2017-01-01

FDA recently approved a 3D-printed drug product in August 2015, which is indicative of a new chapter for pharmaceutical manufacturing. This review article summarizes progress with 3D printed drug products and discusses process development for solid oral dosage forms. 3D printing is a layer-by-layer process capable of producing 3D drug products from digital designs. Traditional pharmaceutical processes, such as tablet compression, have been used for decades with established regulatory pathways. These processes are well understood, but antiquated in terms of process capability and manufacturing flexibility. 3D printing, as a platform technology, has competitive advantages for complex products, personalized products, and products made on-demand. These advantages create opportunities for improving the safety, efficacy, and accessibility of medicines. Although 3D printing differs from traditional manufacturing processes for solid oral dosage forms, risk-based process development is feasible. This review highlights how product and process understanding can facilitate the development of a control strategy for different 3D printing methods. Overall, the authors believe that the recent approval of a 3D printed drug product will stimulate continual innovation in pharmaceutical manufacturing technology. FDA encourages the development of advanced manufacturing technologies, including 3D-printing, using science- and risk-based approaches. Published by Elsevier B.V.

Surface functionalization of 3D-printed plastics via initiated chemical vapor deposition

PubMed Central

Cheng, Christine

2017-01-01

3D printing is a useful fabrication technique because it offers design flexibility and rapid prototyping. The ability to functionalize the surfaces of 3D-printed objects allows the bulk properties, such as material strength or printability, to be chosen separately from surface properties, which is critical to expanding the breadth of 3D printing applications. In this work, we studied the ability of the initiated chemical vapor deposition (iCVD) process to coat 3D-printed shapes composed of poly(lactic acid) and acrylonitrile butadiene styrene. The thermally insulating properties of 3D-printed plastics pose a challenge to the iCVD process due to large thermal gradients along the structures during processing. In this study, processing parameters such as the substrate temperature and the filament temperature were systematically varied to understand how these parameters affect the uniformity of the coatings along the 3D-printed objects. The 3D-printed objects were coated with both hydrophobic and hydrophilic polymers. Contact angle goniometry and X-ray photoelectron spectroscopy were used to characterize the functionalized surfaces. Our results can enable the use of iCVD to functionalize 3D-printed materials for a range of applications such as tissue scaffolds and microfluidics. PMID:28875099

Method for making precisely configured flakes useful in optical devices

DOEpatents

Trajkovska-Petkoska, Anka [Rochester, NY; Jacobs, Stephen D [Pittsford, NY; Kosc, Tanya Z [Rochester, NY; Marshall, Kenneth L [Rochester, NY

2007-07-03

Precisely configured, especially of geometric shape, flakes of liquid crystal material are made using a mechanically flexible polymer mold with wells having shapes which are precisely configured by making the mold with a photolithographically manufactured or laser printed master. The polymer liquid crystal is poured into the wells in the flexible mold. When the liquid crystal material has solidified, the flexible mold is bent and the flakes are released and collected for use in making an electrooptical cell utilizing the liquid crystal flakes as the active element therein.

Shifting Visual Perspective During Retrieval Shapes Autobiographical Memories

PubMed Central

St Jacques, Peggy L.; Szpunar, Karl K.; Schacter, Daniel L.

2016-01-01

The dynamic and flexible nature of memories is evident in our ability to adopt multiple visual perspectives. Although autobiographical memories are typically encoded from the visual perspective of our own eyes they can be retrieved from the perspective of an observer looking at our self. Here, we examined the neural mechanisms of shifting visual perspective during long-term memory retrieval and its influence on online and subsequent memories using functional magnetic resonance imaging (fMRI). Participants generated specific autobiographical memories from the last five years and rated their visual perspective. In a separate fMRI session, they were asked to retrieve the memories across three repetitions while maintaining the same visual perspective as their initial rating or by shifting to an alternative perspective. Visual perspective shifting during autobiographical memory retrieval was supported by a linear decrease in neural recruitment across repetitions in the posterior parietal cortices. Additional analyses revealed that the precuneus, in particular, contributed to both online and subsequent changes in the phenomenology of memories. Our findings show that flexibly shifting egocentric perspective during autobiographical memory retrieval is supported by the precuneus, and suggest that this manipulation of mental imagery during retrieval has consequences for how memories are retrieved and later remembered. PMID:27989780

European Research and Development in Hybrid Flexible Electronics

DTIC Science & Technology

2010-07-01

printing lab houses industrial sized screen printers, dryers , roll-to-roll printers capable of flexographic and gravure printing on 10-inch-wide paper ... papers were to be identified within the Web of Science (WoS) by means of a “filter,” described below, and the analysis was intended to provide the...National Science Foundation. Public Papers of the Presidents 120:338. 2 NSF Investing in America’s Future: Strategic Plan FY 2006–2011. Washington, DC

A Model to Aid Topo-Map Interpretation

ERIC Educational Resources Information Center

Westerback, Mary

1976-01-01

Describes how to construct models of contour lines from flexible, colored bell wire. These models are used to illustrate three-dimensional terrain characteristics represented by contour lines printed on a flat map. (MLH)

Transparent and flexible resistive switching memory devices with a very high ON/OFF ratio using gold nanoparticles embedded in a silk protein matrix

NASA Astrophysics Data System (ADS)

Gogurla, Narendar; Mondal, Suvra P.; Sinha, Arun K.; Katiyar, Ajit K.; Banerjee, Writam; Kundu, Subhas C.; Ray, Samit K.

2013-08-01

The growing demand for biomaterials for electrical and optical devices is motivated by the need to make building blocks for the next generation of printable bio-electronic devices. In this study, transparent and flexible resistive memory devices with a very high ON/OFF ratio incorporating gold nanoparticles into the Bombyx mori silk protein fibroin biopolymer are demonstrated. The novel electronic memory effect is based on filamentary switching, which leads to the occurrence of bistable states with an ON/OFF ratio larger than six orders of magnitude. The mechanism of this process is attributed to the formation of conductive filaments through silk fibroin and gold nanoparticles in the nanocomposite. The proposed hybrid bio-inorganic devices show promise for use in future flexible and transparent nanoelectronic systems.

High-performance flexible resistive memory devices based on Al2O3:GeOx composite

NASA Astrophysics Data System (ADS)

Behera, Bhagaban; Maity, Sarmistha; Katiyar, Ajit K.; Das, Samaresh

2018-05-01

In this study a resistive switching random access memory device using Al2O3:GeOx composite thin films on flexible substrate is presented. A bipolar switching characteristic was observed for the co-sputter deposited Al2O3:GeOx composite thin films. Al/Al2O3:GeOx/ITO/PET memory device shows excellent ON/OFF ratio (∼104) and endurance (>500 cycles). GeOx nanocrystals embedded in the Al2O3 matrix have been found to play a significant role in enhancing the switching characteristics by facilitating oxygen vacancy formation. Mechanical endurance was retained even after several bending. The conduction mechanism of the device was qualitatively discussed by considering Ohmic and SCLC conduction. This flexible device is a potential candidate for next-generation electronics device.

Recent Advances of Flexible Data Storage Devices Based on Organic Nanoscaled Materials.

PubMed

Zhou, Li; Mao, Jingyu; Ren, Yi; Han, Su-Ting; Roy, Vellaisamy A L; Zhou, Ye

2018-03-01

Following the trend of miniaturization as per Moore's law, and facing the strong demand of next-generation electronic devices that should be highly portable, wearable, transplantable, and lightweight, growing endeavors have been made to develop novel flexible data storage devices possessing nonvolatile ability, high-density storage, high-switching speed, and reliable endurance properties. Nonvolatile organic data storage devices including memory devices on the basis of floating-gate, charge-trapping, and ferroelectric architectures, as well as organic resistive memory are believed to be favorable candidates for future data storage applications. In this Review, typical information on device structure, memory characteristics, device operation mechanisms, mechanical properties, challenges, and recent progress of the above categories of flexible data storage devices based on organic nanoscaled materials is summarized. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Architected Lattices with High Stiffness and Toughness via Multicore-Shell 3D Printing.

PubMed

Mueller, Jochen; Raney, Jordan R; Shea, Kristina; Lewis, Jennifer A

2018-03-01

The ability to create architected materials that possess both high stiffness and toughness remains an elusive goal, since these properties are often mutually exclusive. Natural materials, such as bone, overcome such limitations by combining different toughening mechanisms across multiple length scales. Here, a new method for creating architected lattices composed of core-shell struts that are both stiff and tough is reported. Specifically, these lattices contain orthotropic struts with flexible epoxy core-brittle epoxy shell motifs in the absence and presence of an elastomeric silicone interfacial layer, which are fabricated by a multicore-shell, 3D printing technique. It is found that architected lattices produced with a flexible core-elastomeric interface-brittle shell motif exhibit both high stiffness and toughness. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Marked Object Recognition Multitouch Screen Printed Touchpad for Interactive Applications.

PubMed

Nunes, Jivago Serrado; Castro, Nelson; Gonçalves, Sergio; Pereira, Nélson; Correia, Vitor; Lanceros-Mendez, Senentxu

2017-12-01

The market for interactive platforms is rapidly growing, and touchscreens have been incorporated in an increasing number of devices. Thus, the area of smart objects and devices is strongly increasing by adding interactive touch and multimedia content, leading to new uses and capabilities. In this work, a flexible screen printed sensor matrix is fabricated based on silver ink in a polyethylene terephthalate (PET) substrate. Diamond shaped capacitive electrodes coupled with conventional capacitive reading electronics enables fabrication of a highly functional capacitive touchpad, and also allows for the identification of marked objects. For the latter, the capacitive signatures are identified by intersecting points and distances between them. Thus, this work demonstrates the applicability of a low cost method using royalty-free geometries and technologies for the development of flexible multitouch touchpads for the implementation of interactive and object recognition applications.

Marked Object Recognition Multitouch Screen Printed Touchpad for Interactive Applications

PubMed Central

Nunes, Jivago Serrado; Castro, Nelson; Pereira, Nélson; Correia, Vitor; Lanceros-Mendez, Senentxu

2017-01-01

The market for interactive platforms is rapidly growing, and touchscreens have been incorporated in an increasing number of devices. Thus, the area of smart objects and devices is strongly increasing by adding interactive touch and multimedia content, leading to new uses and capabilities. In this work, a flexible screen printed sensor matrix is fabricated based on silver ink in a polyethylene terephthalate (PET) substrate. Diamond shaped capacitive electrodes coupled with conventional capacitive reading electronics enables fabrication of a highly functional capacitive touchpad, and also allows for the identification of marked objects. For the latter, the capacitive signatures are identified by intersecting points and distances between them. Thus, this work demonstrates the applicability of a low cost method using royalty-free geometries and technologies for the development of flexible multitouch touchpads for the implementation of interactive and object recognition applications. PMID:29194414

Flexible ambipolar organic field-effect transistors with reverse-offset-printed silver electrodes for a complementary inverter.

PubMed

Park, Junsu; Kim, Minseok; Yeom, Seung-Won; Ha, Hyeon Jun; Song, Hyenggun; Min Jhon, Young; Kim, Yun-Hi; Ju, Byeong-Kwon

2016-06-03

We report ambipolar organic field-effect transistors and complementary inverter circuits with reverse-offset-printed (ROP) Ag electrodes fabricated on a flexible substrate. A diketopyrrolopyrrole-based co-polymer (PDPP-TAT) was used as the semiconductor and poly(methyl methacrylate) was used as the gate insulator. Considerable improvement is observed in the n-channel electrical characteristics by inserting a cesium carbonate (Cs2CO3) as the electron-injection/hole-blocking layer at the interface between the semiconductors and the electrodes. The saturation mobility values are 0.35 cm(2) V(-1) s(-1) for the p-channel and 0.027 cm(2) V(-1) s(-1) for the n-channel. A complementary inverter is demonstrated based on the ROP process, and it is selectively controlled by the insertion of Cs2CO3 onto the n-channel region via thermal evaporation. Moreover, the devices show stable operation during the mechanical bending test using tensile strains ranging from 0.05% to 0.5%. The results confirm that these devices have great potential for use in flexible and inexpensive integrated circuits over a large area.

From dead leaves to sustainable organic resistive switching memory.

PubMed

Sun, Bai; Zhu, Shouhui; Mao, Shuangsuo; Zheng, Pingping; Xia, Yudong; Yang, Feng; Lei, Ming; Zhao, Yong

2018-03-01

An environmental-friendly, sustainable, pollution-free, biodegradable, flexible and wearable electronic device hold advanced potential applications. Here, an organic resistive switching memory device with Ag/Leaves/Ti/PET structure on a flexible polyethylene terephthalate (PET) substrate was fabricated for the first time. We observed an obvious resistive switching memory characteristic with large switching resistance ratio and stable cycle performance at room temperature. This work demonstrates that leaves, a useless waste, can be properly treated to make useful devices. Furthermore, the as-fabricated devices can be degraded naturally without damage to the environment. Copyright © 2017 Elsevier Inc. All rights reserved.

Structural Integration of Silicon Solar Cells and Lithium-ion Batteries Using Printed Electronics

NASA Astrophysics Data System (ADS)

Kang, Jin Sung

Inkjet printing of electrode using copper nanoparticle ink is presented. Electrode was printed on a flexible glass epoxy composite substrate using drop on demand piezoelectric dispenser and was sintered at 200°C in N 2 gas condition. The printed electrodes were made with various widths and thicknesses. Surface morphology of electrode was analyzed using scanning electron microscope (SEM) and atomic force microscope (AFM). Reliable dimensions for printed electronics were found from this study. Single-crystalline silicon solar cells were tested under four-point bending to find the feasibility of directly integrating them onto a carbon fiber/epoxy composite laminate. These solar cells were not able to withstand 0.2% strain. On the other hand, thin-film amorphous silicon solar cells were subjected to flexural fatigue loadings. The current density-voltage curves were analyzed at different cycles, and there was no noticeable degradation on its performance up to 100 cycles. A multifunctional composite laminate which can harvest and store solar energy was fabricated using printed electrodes. The integrated printed circuit board (PCB) was co-cured with a carbon/epoxy composite laminate by the vacuum bag molding process in an autoclave; an amorphous silicon solar cell and a thin-film solid state lithium-ion (Li-ion) battery were adhesively joined and electrically connected to a thin flexible PCB; and then the passive components such as resistors and diodes were electrically connected to the printed circuit board by silver pasting. Since a thin-film solid state Li-ion battery was not able to withstand tensile strain above 0.4%, thin Li-ion polymer batteries were tested under various mechanical loadings and environmental conditions to find the feasibility of using the polymer batteries for our multifunctional purpose. It was found that the Li-ion polymer batteries were stable under pressure and tensile loading without any noticeable degradation on its charge and discharge performances. Also, the active materials did not decompose at 80°C, and the battery was performing well under low temperature of -27°C. Lastly, the batteries were embedded inside a carbon fiber/epoxy composite laminate to characterize their performance under fatigue loading. Finally, an intense pulsed light (IPL) was used to sinter printed silver nanoink patterns. X-ray diffraction (XRD) was used to find grain size of printed silver nanoink patterns. From these analyses it was confirmed that IPL is able to adequately sinter silver nanoink patterns for printed electronics without degradation of the substrates in less than 30 ms.

Design of a 4D Printing System Using Thermal Sensitive Smart Materials and Photoactivated Shape Changing Polymers

NASA Astrophysics Data System (ADS)

Leist, Steven Kyle

4D printing is an emerging additive manufacturing technology that combines 3D printing with smart materials. Current 3D printing technology can print objects with a multitude of materials; however, these objects are usually static, geometrically permanent, and not suitable for multi-functional use. The 4D printed objects can change their shape over time when exposed to different external stimuli such as heat, pressure, magnetic fields, or moisture. In this research, heat and light reactive smart materials are explored as a 4D printing materials. Synthetization of a material that actuates when exposed to stimulus can be a very difficult process, and merging that same material with the ability to be 3D printed can be further difficult. A common 3D printing thermoplastic, poly(lactic) acid (PLA), is used as a shape memory material that is 3D printed using a fused deposition machine (FDM) and combined with nylon fabric for the exploration of smart textiles. The research shows that post printed PLA possesses shape memory properties depending on the thickness of the 3D printed material and the activation temperature. PLA can be thermomechanically trained into temporary shapes and return to its original shape when exposed to high temperatures. PLA can be 3D printed onto nylon fabrics for the creation of the smart textiles. Additionally, a photoisomerable shape changing material is explored because light activation is wireless, controllable, focusable, abundant, causes rapid shape change of the smart material, and induces reversible shape change in the material. This study supports the fundamental research to generate knowledge needed for synthesis of a novel azobenzene shape changing polymer (SCP) and integrating this smart material into objects printed with a 4D printing process using syringe printing. Multiple versions of azobenzene SCP are synthesized that actuate when exposed to 365 nm and 455 nm light. Two SCPs, MeOABHx and DR1Hx, are selected for the 4D printing research because of their ability to photoisomerize at room temperature and 3D printability. The physical properties of these polymers are characterized, photomechanical bending tests are performed, and the photo-generated stress is measured using a dynamic mechanical analyzer (DMA). The SCPs are deposited onto a passive layer to create bilayer films in order to actuate. The photomechanical efficiency of bilayer films is evaluated depending on the thickness of the passive layer film, type of azobenzene SCP, wavelength of the light source, intensity of the light source, and distance between the light and films. 4D printing can be used to streamline the design and manufacturing process of actuating parts. Complex heavy parts can be removed from actuation systems such as onboard power storage, motors, sensors, and processors by embedding these capabilities into the material themselves. This reduces the amount of required parts, the amount of materials, and reduces the cost of producing these parts. 4D printed products possess the properties of programmability, reaction and adaption to their environment, and automation. Therefore, they can find wider applications including foldable unmanned aerial vehicles, artificial muscles, grippers, biomedical drug delivery systems, stents, and minimally invasive surgeries.

Solar Trees: First Large-Scale Demonstration of Fully Solution Coated, Semitransparent, Flexible Organic Photovoltaic Modules.

PubMed

Berny, Stephane; Blouin, Nicolas; Distler, Andreas; Egelhaaf, Hans-Joachim; Krompiec, Michal; Lohr, Andreas; Lozman, Owen R; Morse, Graham E; Nanson, Lana; Pron, Agnieszka; Sauermann, Tobias; Seidler, Nico; Tierney, Steve; Tiwana, Priti; Wagner, Michael; Wilson, Henry

2016-05-01

The technology behind a large area array of flexible solar cells with a unique design and semitransparent blue appearance is presented. These modules are implemented in a solar tree installation at the German pavilion in the EXPO2015 in Milan/IT. The modules show power conversion efficiencies of 4.5% and are produced exclusively using standard printing techniques for large-scale production.

Foldable and Disposable Memory on Paper

PubMed Central

Lee, Byung-Hyun; Lee, Dong-Il; Bae, Hagyoul; Seong, Hyejeong; Jeon, Seung-Bae; Seol, Myung-Lok; Han, Jin-Woo; Meyyappan, M.; Im, Sung-Gap; Choi, Yang-Kyu

2016-01-01

Foldable organic memory on cellulose nanofibril paper with bendable and rollable characteristics is demonstrated by employing initiated chemical vapor deposition (iCVD) for polymerization of the resistive switching layer and inkjet printing of the electrode, where iCVD based on all-dry and room temperature process is very suitable for paper electronics. This memory exhibits a low operation voltage of 1.5 V enabling battery operation compared to previous reports and wide memory window. The memory performance is maintained after folding tests, showing high endurance. Furthermore, the quick and complete disposable nature demonstrated here is attractive for security applications. This work provides an effective platform for green, foldable and disposable electronics based on low cost and versatile materials. PMID:27922094

A flexible, gigahertz, and free-standing thin film piezoelectric MEMS resonator with high figure of merit

NASA Astrophysics Data System (ADS)

Jiang, Yuan; Zhang, Menglun; Duan, Xuexin; Zhang, Hao; Pang, Wei

2017-07-01

In this paper, a 2.6 GHz air-gap type thin film piezoelectric MEMS resonator was fabricated on a flexible polyethylene terephthalate film. A fabrication process combining transfer printing and hot-embossing was adopted to form a free-standing structure. The flexible radio frequency MEMS resonator possesses a quality factor of 946 and an effective coupling coefficient of 5.10%, and retains its high performance at a substrate bending radius of 1 cm. The achieved performance is comparable to that of conventional resonators on rigid silicon wafers. Our demonstration provides a viable approach to realizing universal MEMS devices on flexible polymer substrates, which is of great significance for building future fully integrated and multi-functional wireless flexible electronic systems.

Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

PubMed Central

McClelland, Megan M.; Cameron, Claire E.; Duncan, Robert; Bowles, Ryan P.; Acock, Alan C.; Miao, Alicia; Pratt, Megan E.

2014-01-01

Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics. PMID:25071619

6 DOF Nonlinear AUV Simulation Toolbox

DTIC Science & Technology

1997-01-01

is to supply a flexible 3D -simulation platform for motion visualization, in-lab debugging and testing of mission-specific strategies as well as those...Explorer are modular designed [Smith] in order to cut time and cost for vehicle recontlguration. A flexible 3D -simulation platform is desired to... 3D models. Current implemented modules include a nonlinear dynamic model for the OEX, shared memory and semaphore manager tools, shared memory monitor

Cost-effective, transfer-free, flexible resistive random access memory using laser-scribed reduced graphene oxide patterning technology.

PubMed

Tian, He; Chen, Hong-Yu; Ren, Tian-Ling; Li, Cheng; Xue, Qing-Tang; Mohammad, Mohammad Ali; Wu, Can; Yang, Yi; Wong, H-S Philip

2014-06-11

Laser scribing is an attractive reduced graphene oxide (rGO) growth and patterning technology because the process is low-cost, time-efficient, transfer-free, and flexible. Various laser-scribed rGO (LSG) components such as capacitors, gas sensors, and strain sensors have been demonstrated. However, obstacles remain toward practical application of the technology where all the components of a system are fabricated using laser scribing. Memory components, if developed, will substantially broaden the application space of low-cost, flexible electronic systems. For the first time, a low-cost approach to fabricate resistive random access memory (ReRAM) using laser-scribed rGO as the bottom electrode is experimentally demonstrated. The one-step laser scribing technology allows transfer-free rGO synthesis directly on flexible substrates or non-flat substrates. Using this time-efficient laser-scribing technology, the patterning of a memory-array area up to 100 cm(2) can be completed in 25 min. Without requiring the photoresist coating for lithography, the surface of patterned rGO remains as clean as its pristine state. Ag/HfOx/LSG ReRAM using laser-scribing technology is fabricated in this work. Comprehensive electrical characteristics are presented including forming-free behavior, stable switching, reasonable reliability performance and potential for 2-bit storage per memory cell. The results suggest that laser-scribing technology can potentially produce more cost-effective and time-effective rGO-based circuits and systems for practical applications.

Digital printing

NASA Astrophysics Data System (ADS)

Sobotka, Werner K.

1997-02-01

Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

Fabrication of a printed capacitive air-gap touch sensor

NASA Astrophysics Data System (ADS)

Lee, Sang Hoon; Seo, Hwiwon; Lee, Sangyoon

2018-05-01

Unlike lithography-based processes, printed electronics does not require etching, which makes it difficult to fabricate electronic devices with an air gap. In this study, we propose a method to fabricate capacitive air-gap touch sensors via printing and coating. First, the bottom electrode was fabricated on a flexible poly(ethylene terephthalate) (PET) substrate using roll-to-roll gravure printing with silver ink. Then poly(dimethylsiloxane) (PDMS) was spin coated to form a sacrificial layer. The top electrode was fabricated on the sacrificial layer by spin coating with a stretchable silver ink. The sensor samples were then put in a tetrabutylammonium (TBAF) bath to generate the air gap by removing the sacrificial layer. The capacitance of the samples was measured for verification, and the results show that the capacitance increases in proportion to the applied force from 0 to 2.5 N.

Shear induced alignment of short nanofibers in 3D printed polymer composites.

PubMed

Yunus, Doruk Erdem; Shi, Wentao; Sohrabi, Salman; Liu, Yaling

2016-12-09

3D printing of composite materials offers an opportunity to combine the desired properties of composite materials with the flexibility of additive manufacturing in geometric shape and complexity. In this paper, the shear-induced alignment of aluminum oxide nanowires during stereolithography printing was utilized to fabricate a nanowire reinforced polymer composite. To align the fibers, a lateral oscillation mechanism was implemented and combined with wall pattern printing technique to generate shear flow in both vertical and horizontal directions. A series of specimens were fabricated for testing the composite material's tensile strength. The results showed that mechanical properties of the composite were improved by reinforcement of nanofibers through shear induced alignment. The improvement of tensile strength was approximately ∼28% by aligning the nanowires at 5 wt% (∼1.5% volume fraction) loading of aluminum oxide nanowires.

Media and Memory: The Impact of Presentation Style on Middle Aged and Older Adults' Recall of Health Information

ERIC Educational Resources Information Center

Wilson, Elizabeth Anne Hamann

2009-01-01

Educational tools such as printed pamphlets and videos can enhance patients' understanding and memory of health-related information, but in order for such materials to be effective, designers of such tools should take care to understand the impact of variables such as the medium in which information is displayed, the type of information to be…

Memory: As It Relates to Children Ages 9 to 12 Years. Skills Essential to Learning Television Project: Working Paper.

ERIC Educational Resources Information Center

Perry, Fred L., Jr.

An overview of theory and research in memory as it relates to developmental differences is offered in this paper, which is intended to provide background information for the staff of the Skills Essential to Learning Television Project (a multi-level series of video and print resources for classroom use). A model for viewing information processing…

Characterization of screen-printed electrodes for dielectric elastomer (DE) membranes: influence of screen dimensions and electrode thickness on actuator performance

NASA Astrophysics Data System (ADS)

Fasolt, Bettina; Hodgins, Micah; Seelecke, Stefan

2016-04-01

Screen printing is used as a method for printing electrodes on silicone thin films for the fabrication of dielectric elastomer transducers (DET). This method can be used to manufacture a multitude of patternable designs for actuator and sensor applications, implementing the same method for prototyping as well as large-scale production. The fabrication of DETs does not only require the development of a flexible, highly conductive electrode material, which adheres to a stretched and unstretched silicone film, but also calls for a thorough understanding of the effects of the different printing parameters. This work studies the influence of screen dimensions (open area, mesh thickness) as well as the influence of multiple-layer- printing on the electrode stiffness, electrical resistance and capacitance as well as actuator performance. The investigation was conducted in a custom-built testing device, which enabled an electro-mechanical characterization of the DET, simultaneously measuring parameters such as strain, voltage, current, force, sheet resistance, capacitance and membrane thickness. Magnified pictures of the electrodes will additionally illustrate the effects of the different printing parameters.

A High Precision $3.50 Open Source 3D Printed Rain Gauge Calibrator

NASA Astrophysics Data System (ADS)

Lopez Alcala, J. M.; Udell, C.; Selker, J. S.

2017-12-01

Currently available rain gauge calibrators tend to be designed for specific rain gauges, are expensive, employ low-precision water reservoirs, and do not offer the flexibility needed to test the ever more popular small-aperture rain gauges. The objective of this project was to develop and validate a freely downloadable, open-source, 3D printed rain gauge calibrator that can be adjusted for a wide range of gauges. The proposed calibrator provides for applying low, medium, and high intensity flow, and allows the user to modify the design to conform to unique system specifications based on parametric design, which may be modified and printed using CAD software. To overcome the fact that different 3D printers yield different print qualities, we devised a simple post-printing step that controlled critical dimensions to assure robust performance. Specifically, the three orifices of the calibrator are drilled to reach the three target flow rates. Laboratory tests showed that flow rates were consistent between prints, and between trials of each part, while the total applied water was precisely controlled by the use of a volumetric flask as the reservoir.

Laser-induced forward transfer for printed electronics applications

NASA Astrophysics Data System (ADS)

Fernández-Pradas, J. M.; Sopeña, P.; González-Torres, S.; Arrese, J.; Cirera, A.; Serra, P.

2018-02-01

Laser-induced forward transfer (LIFT) is a printing technique based on the action of a laser pulse that is focused on a thin film of a precursor ink for getting the transfer of a droplet onto a receiver substrate. The experiments presented in this article aim to demonstrate the ability of LIFT to produce electronic circuits on paper, a substrate that is flexible, cheap and recyclable. Tests were conducted to study the printing of conductive tracks with an Ag ink. The printing of a suspension of carbon nanofibers was also studied to demonstrate the ability of LIFT for printing inks with particles with some microns in size that provoke inkjet nozzles to clog. As a proof-of-concept of the LIFT possibilities, both inks were used to print entirely by LIFT a functional humidity sensor on a piece of paper. All the LIFT experiments were performed with a Nd:YAG laser that delivers pulses of a few hundreds of ns in an attempt to approach the technique to laser systems that are already introduced in many production lines for marking and labeling.

Solving the Big Data (BD) Problem in Advanced Manufacturing (Subcategory for work done at Georgia Tech. Study Process and Design Factors for Additive Manufacturing Improvement)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Brett W.; Diaz, Kimberly A.; Ochiobi, Chinaza Darlene

2015-09-01

3D printing originally known as additive manufacturing is a process of making 3 dimensional solid objects from a CAD file. This ground breaking technology is widely used for industrial and biomedical purposes such as building objects, tools, body parts and cosmetics. An important benefit of 3D printing is the cost reduction and manufacturing flexibility; complex parts are built at the fraction of the price. However, layer by layer printing of complex shapes adds error due to the surface roughness. Any such error results in poor quality products with inaccurate dimensions. The main purpose of this research is to measure themore » amount of printing errors for parts with different geometric shapes and to analyze them for finding optimal printing settings to minimize the error. We use a Design of Experiments framework, and focus on studying parts with cone and ellipsoid shapes. We found that the orientation and the shape of geometric shapes have significant effect on the printing error. From our analysis, we also determined the optimal orientation that gives the least printing error.« less

Functional inks and printing of two-dimensional materials.

PubMed

Hu, Guohua; Kang, Joohoon; Ng, Leonard W T; Zhu, Xiaoxi; Howe, Richard C T; Jones, Christopher G; Hersam, Mark C; Hasan, Tawfique

2018-05-08

Graphene and related two-dimensional materials provide an ideal platform for next generation disruptive technologies and applications. Exploiting these solution-processed two-dimensional materials in printing can accelerate this development by allowing additive patterning on both rigid and conformable substrates for flexible device design and large-scale, high-speed, cost-effective manufacturing. In this review, we summarise the current progress on ink formulation of two-dimensional materials and the printable applications enabled by them. We also present our perspectives on their research and technological future prospects.

Private Company Flexibility and Growth Act

THOMAS, 112th Congress

Sen. Toomey, Pat [R-PA

2011-11-08

Senate - 03/06/2012 Committee on Banking, Housing, and Urban Affairs. Hearings held. Hearings printed: S.Hrg. 112-482. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

War Memorial Protection Act of 2013

THOMAS, 113th Congress

Sen. Burr, Richard [R-NC

2013-04-11

Senate - 06/12/2013 Committee on Veterans' Affairs. Hearings held. Hearings printed: S.Hrg. 113-111. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Beyond flexible batteries: aesthetically versatile, printed rechargeable power sources for smart electronics

NASA Astrophysics Data System (ADS)

Lee, Sang-Young

2017-05-01

Forthcoming wearable/flexible electronics with compelling shape diversity and mobile usability have garnered significant attention as a kind of disruptive technology to drastically change our daily lives. From a power source point of view, conventional rechargeable batteries (represented by lithium-ion batteries) with fixed shapes and dimensions are generally fabricated by winding (or stacking) cell components (such as anodes, cathodes and separator membranes) and then packaging them with (cylindrical-/rectangular-shaped) metallic canisters or pouch films, finally followed by injection of liquid electrolytes. In particular, the use of liquid electrolytes gives rise to serious concerns in cell assembly, because they require strict packaging materials to avoid leakage problems and also separator membranes to prevent electrical contact between electrodes. For these reasons, the conventional cell assembly and materials have pushed the batteries to lack of variety in form factors, thus imposing formidable challenges on their integration into versatile-shaped electronic devices. Here, as a facile and efficient strategy to address the aforementioned longstanding challenge, we demonstrate a new class of printed solid-state Li-ion batteries and also all-inkjet-printed solid-state supercapacitors with exceptional shape conformability and aesthetic versatility which lie far beyond those achievable with conventional battery technologies.

Fully inkjet-printed microfluidics: a solution to low-cost rapid three-dimensional microfluidics fabrication with numerous electrical and sensing applications

PubMed Central

Su, Wenjing; Cook, Benjamin S.; Fang, Yunnan; Tentzeris, Manos M.

2016-01-01

As the needs for low-cost rapidly-produced microfluidics are growing with the trend of Lab-on-a-Chip and distributed healthcare, the fully inkjet-printing of microfluidics can be a solution to it with numerous potential electrical and sensing applications. Inkjet-printing is an additive manufacturing technique featuring no material waste and a low equipment cost. Moreover, similar to other additive manufacturing techniques, inkjet-printing is easy to learn and has a high fabrication speed, while it offers generally a great planar resolution down to below 20 µm and enables flexible designs due to its inherent thin film deposition capabilities. Due to the thin film feature, the printed objects also usually obtain a high vertical resolution (such as 4.6 µm). This paper introduces a low-cost rapid three-dimensional fabrication process of microfluidics, that relies entirely on an inkjet-printer based single platform and can be implemented directly on top of virtually any substrates. PMID:27713545

Large dynamic range digital nanodot gradients of biomolecules made by low-cost nanocontact printing for cell haptotaxis.

PubMed

Ricoult, Sébastien G; Pla-Roca, Mateu; Safavieh, Roozbeh; Lopez-Ayon, G Monserratt; Grütter, Peter; Kennedy, Timothy E; Juncker, David

2013-10-11

A novel method is introduced for ultrahigh throughput and ultralow cost patterning of biomolecules with nanometer resolution and novel 2D digital nanodot gradients (DNGs) with mathematically defined slopes are created. The technique is based on lift-off nanocontact printing while using high-resolution photopolymer stamps that are rapidly produced at a low cost through double replication from Si originals. Printed patterns with 100 nm features are shown. DNGs with varying spacing between the dots and a record dynamic range of 4400 are produced; 64 unique DNGs, each with hundreds of thousands of dots, are inked and printed in 5.5 min. The adhesive response and haptotaxis of C2C12 myoblast cells on DNGs demonstrated their biofunctionality. The great flexibility in pattern design, the massive parallel ability, the ultra low cost, and the extreme ease of polymer lift-off nanocontact printing will facilitate its use for various biological and medical applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A study on Aerosol jet printing technology in LED module manufacturing

NASA Astrophysics Data System (ADS)

Rudorfer, Andreas; Tscherner, Martin; Palfinger, Christian; Reil, Frank; Hartmann, Paul; Seferis, Ioannis E.; Zych, Eugeniusz; Wenzl, Franz P.

2016-09-01

State of the art fabrication of LED modules based on chip-on-board (COB) technology comprises some shortcomings both with respect to the manufacturing process itself but also with regard to potential sources of failures and manufacturing impreciseness. One promising alternative is additive manufacturing, a technology which has gained a lot of attention during the last years due to its materials and cost saving capabilities. Especially direct-write technologies like Aerosol jet printing have demonstrated advantages compared to other technological approaches when printing high precision layers or high precision electronic circuits on substrates which, as an additional advantage, also can be flexible and 3D shaped. Based on test samples and test structures manufactured by Aerosol jet printing technology, in this context we discuss the potentials of additive manufacturing in various aspects of LED module fabrication, ranging from the deposition of the die-attach material, wire bond replacement by printed electrical connects as well as aspects of high-precision phosphor layer deposition for color conversion and white light generation.

A Low-Cost Inkjet-Printed Aptamer-Based Electrochemical Biosensor for the Selective Detection of Lysozyme.

PubMed

Khan, Niazul Islam; Maddaus, Alec G; Song, Edward

2018-01-15

Recently, inkjet-printing has gained increased popularity in applications such as flexible electronics and disposable sensors, as well as in wearable sensors because of its multifarious advantages. This work presents a novel, low-cost immobilization technique using inkjet-printing for the development of an aptamer-based biosensor for the detection of lysozyme, an important biomarker in various disease diagnosis. The strong affinity between the carbon nanotube (CNT) and the single-stranded DNA is exploited to immobilize the aptamers onto the working electrode by printing the ink containing the dispersion of CNT-aptamer complex. The inkjet-printing method enables aptamer density control, as well as high resolution patternability. Our developed sensor shows a detection limit of 90 ng/mL with high target selectivity against other proteins. The sensor also demonstrates a shelf-life for a reasonable period. This technology has potential for applications in developing low-cost point-of-care diagnostic testing kits for home healthcare.

Fully inkjet-printed microfluidics: a solution to low-cost rapid three-dimensional microfluidics fabrication with numerous electrical and sensing applications

NASA Astrophysics Data System (ADS)

Su, Wenjing; Cook, Benjamin S.; Fang, Yunnan; Tentzeris, Manos M.

2016-10-01

As the needs for low-cost rapidly-produced microfluidics are growing with the trend of Lab-on-a-Chip and distributed healthcare, the fully inkjet-printing of microfluidics can be a solution to it with numerous potential electrical and sensing applications. Inkjet-printing is an additive manufacturing technique featuring no material waste and a low equipment cost. Moreover, similar to other additive manufacturing techniques, inkjet-printing is easy to learn and has a high fabrication speed, while it offers generally a great planar resolution down to below 20 µm and enables flexible designs due to its inherent thin film deposition capabilities. Due to the thin film feature, the printed objects also usually obtain a high vertical resolution (such as 4.6 µm). This paper introduces a low-cost rapid three-dimensional fabrication process of microfluidics, that relies entirely on an inkjet-printer based single platform and can be implemented directly on top of virtually any substrates.

All-inkjet-printed thin-film transistors: manufacturing process reliability by root cause analysis.

PubMed

Sowade, Enrico; Ramon, Eloi; Mitra, Kalyan Yoti; Martínez-Domingo, Carme; Pedró, Marta; Pallarès, Jofre; Loffredo, Fausta; Villani, Fulvia; Gomes, Henrique L; Terés, Lluís; Baumann, Reinhard R

2016-09-21

We report on the detailed electrical investigation of all-inkjet-printed thin-film transistor (TFT) arrays focusing on TFT failures and their origins. The TFT arrays were manufactured on flexible polymer substrates in ambient condition without the need for cleanroom environment or inert atmosphere and at a maximum temperature of 150 °C. Alternative manufacturing processes for electronic devices such as inkjet printing suffer from lower accuracy compared to traditional microelectronic manufacturing methods. Furthermore, usually printing methods do not allow the manufacturing of electronic devices with high yield (high number of functional devices). In general, the manufacturing yield is much lower compared to the established conventional manufacturing methods based on lithography. Thus, the focus of this contribution is set on a comprehensive analysis of defective TFTs printed by inkjet technology. Based on root cause analysis, we present the defects by developing failure categories and discuss the reasons for the defects. This procedure identifies failure origins and allows the optimization of the manufacturing resulting finally to a yield improvement.

Micro-masonry for 3D additive micromanufacturing.

PubMed

Keum, Hohyun; Kim, Seok

2014-08-01

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called 'inks') from a substrate where they are generated to a different substrate by utilizing elastomeric stamps. Transfer printing enables the integration of heterogeneous materials to fabricate unexampled structures or functional systems that are found in recent advanced devices such as flexible and stretchable solar cells and LED arrays. While transfer printing exhibits unique features in material assembly capability, the use of adhesive layers or the surface modification such as deposition of self-assembled monolayer (SAM) on substrates for enhancing printing processes hinders its wide adaptation in microassembly of microelectromechanical system (MEMS) structures and devices. To overcome this shortcoming, we developed an advanced mode of transfer printing which deterministically assembles individual microscale objects solely through controlling surface contact area without any surface alteration. The absence of an adhesive layer or other modification and the subsequent material bonding processes ensure not only mechanical bonding, but also thermal and electrical connection between assembled materials, which further opens various applications in adaptation in building unusual MEMS devices.

Fully Printed Ultraflexible Supercapacitor Supported by a Single-Textile Substrate.

PubMed

Zhang, Huihui; Qiao, Yan; Lu, Zhisong

2016-11-30

Textile-based supercapacitors have recently attracted much attention owing to their great potential as energy storage components in wearable electronics. However, fabrication of a high-performance, fully printed, and ultraflexible supercapacitor based on a single textile still remains a great challenge. Herein, a facile, low-cost, and textile-compatible method involving screen printing and transfer printing is developed to construct all-solid-state supercapacitors on a single silk fabric. The system exhibits a high specific capacitance of 19.23 mF cm -2 at a current density of 1 mA cm -2 and excellent cycling stability with capacitance retention of 84% after 2000 charging/discharging cycles. In addition, the device possesses superior mechanical stability with stable performance and structures after 100 times of bending and twisting. A butterfly-patterned supercapacitor was manufactured to demonstrate the compatibility of the printing approaches to textile aesthetics. This work may provide a facile and versatile approach for fabricating rationally designed ultraflexible textile-based power-storage elements for potential applications in smart textiles and stretchable/flexible electronics.

Contactless and absolute linear displacement detection based upon 3D printed magnets combined with passive radio-frequency identification

NASA Astrophysics Data System (ADS)

Windl, Roman; Abert, Claas; Bruckner, Florian; Huber, Christian; Vogler, Christoph; Weitensfelder, Herbert; Suess, Dieter

2017-11-01

Within this work a passive and wireless magnetic sensor, to monitor linear displacements, is proposed. We exploit recent advances in 3D printing and fabricate a polymer bonded magnet with a spatially linear magnetic field component corresponding to the length of the magnet. Regulating the magnetic compound fraction during printing allows specific shaping of the magnetic field distribution. A giant magnetoresistance magnetic field sensor is combined with a radio-frequency identification tag in order to passively monitor the exerted magnetic field of the printed magnet. Due to the tailored magnetic field, a displacement of the magnet with respect to the sensor can be detected within the sub-mm regime. The sensor design provides good flexibility by controlling the 3D printing process according to application needs. Absolute displacement detection using low cost components and providing passive operation, long term stability, and longevity renders the proposed sensor system ideal for structural health monitoring applications.

4D printing of a self-morphing polymer driven by a swellable guest medium.

PubMed

Su, Jheng-Wun; Tao, Xiang; Deng, Heng; Zhang, Cheng; Jiang, Shan; Lin, Yuyi; Lin, Jian

2018-01-31

There is a significant need of advanced materials that can be fabricated into functional devices with defined three-dimensional (3D) structures for application in tissue engineering, flexible electronics, and soft robotics. This need motivates an emerging four-dimensional (4D) printing technology, by which printed 3D structures consisting of active materials can transform their configurations over time in response to stimuli. Despite the ubiquity of active materials in performing self-morphing processes, their potential for 4D printing has not been fully explored to date. In this study, we demonstrate 4D printing of a commercial polymer, SU-8, which has not been reported to date in this field. The working principle is based on a self-morphing process of the printed SU-8 structures through spatial control of the swelling medium inside the polymer matrix by a modified process. To understand the self-morphing behavior, fundamental studies on the effect of the geometries including contours and filling patterns were carried out. A soft electronic device as an actuator was demonstrated to realize an application of this programmable polymer using the 3D printing technology. These studies provide a new paradigm for application of SU-8 in 4D printing, paving a new route to the exploration of more potential candidates by this demonstrated strategy.

Single step high-speed printing of continuous silver lines by laser-induced forward transfer

NASA Astrophysics Data System (ADS)

Puerto, D.; Biver, E.; Alloncle, A.-P.; Delaporte, Ph.

2016-06-01

The development of high-speed ink printing process by Laser-Induced Forward Transfer (LIFT) is of great interest for the printing community. To address the problems and the limitations of this process that have been previously identified, we have performed an experimental study on laser micro-printing of silver nanoparticle inks by LIFT and demonstrated for the first time the printing of continuous conductive lines in a single pass at velocities of 17 m/s using a 1 MHz repetition rate laser. We investigated the printing process by means of a time-resolved imaging technique to visualize the ejection dynamics of single and adjacent jets. The control of the donor film properties is of prime importance to achieve single step printing of continuous lines at high velocities. We use a 30 ps pulse duration laser with a wavelength of 343 nm and a repetition rate from 0.2 to 1 MHz. A galvanometric mirror head controls the distance between two consecutives jets by scanning the focused beam along an ink-coated donor substrate at different velocities. Droplets and lines of silver inks are laser-printed on glass and PET flexible substrates and we characterized their morphological quality by atomic force microscope (AFM) and optical microscope.

Investigation of Dynamic Crack Coalescence Using a Gypsum-Like 3D Printing Material

NASA Astrophysics Data System (ADS)

Jiang, Chao; Zhao, Gao-Feng; Zhu, Jianbo; Zhao, Yi-Xin; Shen, Luming

2016-10-01

Dynamic crack coalescence attracts great attention in rock mechanics. However, specimen preparation in experimental study is a time-consuming and difficult procedure. In this work, a gypsum-like material by powder bed and inkjet 3D printing technique was applied to produce specimens with preset cracks for split Hopkinson pressure bar (SHPB) test. From micro X-ray CT test, it was found that the 3D printing technique could successfully prepare specimens that contain preset cracks with width of 0.2 mm. Basic mechanical properties of the 3D printing material, i.e., the elastic modulus, the Poisson's ratio, the density, the compressive strength, the indirect tensile strength, and the fracture toughness, were obtained and reported. Unlike 3D printed specimens using polylactic acid, these gypsum-like specimens can produce failure patterns much closer to those observed in classical rock mechanical tests. Finally, the dynamic crack coalescence of the 3D printed specimens with preset cracks were captured using a high-speed camera during SHPB tests. Failure patterns of these 3D printed specimens are similar to the specimens made by Portland cement concrete. Our results indicate that sample preparation by 3D printing is highly competitive due to its quickness in prototyping, precision and flexibility on the geometry, and high material homogeneity.

Optical connections on flexible substrates

NASA Astrophysics Data System (ADS)

Bosman, Erwin; Geerinck, Peter; Christiaens, Wim; Van Steenberge, Geert; Vanfleteren, Jan; Van Daele, Peter

2006-04-01

Optical interconnections integrated on a flexible substrate combine the advantages of optical data transmissions (high bandwidth, no electromagnetic disturbance and low power consumption) and those of flexible substrates (compact, ease of assembly...). Especially the flexible character of the substrates can significantly lower the assembly cost and leads to more compact modules. Especially in automotive-, avionic-, biomedical and sensing applications there is a great potential for these flexible optical interconnections because of the increasing data-rates, increasing use of optical sensors and requirement for smaller size and weight. The research concentrates on the integration of commercially available polymer optical layers (Truemode Backplane TM Polymer, Ormocer®) on a flexible Polyimide film, the fabrication of waveguides and out-of plane deflecting 45° mirrors, the characterization of the optical losses due to the bending of the substrate, and the fabrication of a proof-of-principal demonstrator. The resulting optical structures should be compatible with the standard fabrication of flexible printed circuit boards.

Neural correlates of reappraisal considering working memory capacity and cognitive flexibility.

PubMed

Zaehringer, Jenny; Falquez, Rosalux; Schubert, Anna-Lena; Nees, Frauke; Barnow, Sven

2018-01-09

Cognitive reappraisal of emotion is strongly related to long-term mental health. Therefore, the exploration of underlying cognitive and neural mechanisms has become an essential focus of research. Considering that reappraisal and executive functions rely on a similar brain network, the question arises whether behavioral differences in executive functions modulate neural activity during reappraisal. Using functional neuroimaging, the present study aimed to analyze the role of working memory capacity (WMC) and cognitive flexibility in brain activity during down-regulation of negative emotions by reappraisal in N = 20 healthy participants. Results suggests that WMC and cognitive flexibility were negatively correlated with prefrontal activity during reappraisal condition. Here, results also revealed a negative correlation between cognitive flexibility and amygdala activation. These findings provide first hints that (1) individuals with lower WMC and lower cognitive flexibility might need more higher-order cognitive neural resources in order to down-regulate negative emotions and (2) cognitive flexibility relates to emotional reactivity during reappraisal.

Attention-deficit/hyperactivity disorder: the impact of methylphenidate on working memory, inhibition capacity and mental flexibility.

PubMed

Bolfer, Cristiana; Pacheco, Sandra Pasquali; Tsunemi, Miriam Harumi; Carreira, Walter Souza; Casella, Beatriz Borba; Casella, Erasmo Barbante

2017-04-01

To compare children with attention-deficit/hyperactivity disorder (ADHD), before and after the use of methylphenidate, and a control group, using tests of working memory, inhibition capacity and mental flexibility. Neuropsychological tests were administrated to 53 boys, 9-12 years old: the WISC-III digit span backward, and arithmetic; Stroop Color; and Trail Making Tests. The case group included 23 boys with ADHD, who were combined type, treatment-naive, and with normal intelligence without comorbidities. The control group (n = 30) were age and gender matched. After three months on methylphenidate, the ADHD children were retested. The control group was also retested after three months. Before treatment, ADHD children had lower scores than the control group on the tests (p ≤ 0.001) and after methylphenidate had fewer test errors than before (p ≤ 0.001). Methylphenidate treatment improves the working memory, inhibitory control and mental flexibility of ADHD boys.

Factors influencing the role of cardiac autonomic regulation in the service of cognitive control.

PubMed

Capuana, Lesley J; Dywan, Jane; Tays, William J; Elmers, Jamie L; Witherspoon, Richelle; Segalowitz, Sidney J

2014-10-01

Working from a model of neurovisceral integration, we examined whether adding response contingencies and motivational involvement would increase the need for cardiac autonomic regulation in maintaining effective cognitive control. Respiratory sinus arrhythmia (RSA) was recorded during variants of the Stroop color-word task. The Basic task involved "accepting" congruent items and "rejecting" words printed in incongruent colors (BLUE in red font); an added contingency involved rejecting a particular congruent word (e.g., RED in red font), or a congruent word repeated on an immediately subsequent trial. Motivation was increased by adding a financial incentive phase. Results indicate that pre-task RSA predicted accuracy best when response contingencies required the maintenance of a specific item in memory or on the Basic Stroop task when errors resulted in financial loss. Overall, RSA appeared to be most relevant to performance when the task encouraged a more proactive style of cognitive control, a control strategy thought to be more metabolically costly, and hence, more reliant on flexible cardiac autonomic regulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Executive control deficits in substance-dependent individuals: a comparison of alcohol, cocaine, and methamphetamine and of men and women.

PubMed

van der Plas, Ellen A A; Crone, Eveline A; van den Wildenberg, Wery P M; Tranel, Daniel; Bechara, Antoine

2009-08-01

Substance dependence is associated with executive function deficits, but the nature of these executive defects and the effect that different drugs and sex have on these defects have not been fully clarified. Therefore, we compared the performance of alcohol- (n = 33; 18 women), cocaine- (n = 27; 14 women), and methamphetamine-dependent individuals (n = 38; 25 women) with sex-matched healthy comparisons (n = 36; 17 women) on complex decision making as measured with the Iowa Gambling Task, working memory, cognitive flexibility, and response inhibition. Cocaine- and methamphetamine-dependent individuals were impaired on complex decision making, working memory, and cognitive flexibility, but not on response inhibition. The deficits in working memory and cognitive flexibility were milder than the decision-making deficits and did not change as a function of memory load or task switching. Interestingly, decision making was significantly more impaired in women addicted to cocaine or methamphetamine than in men addicted to these drugs. Together, these findings suggest that drug of choice and sex have different effects on executive functioning, which, if replicated, may help tailor intervention.

Flexible non-volatile memory devices based on organic semiconductors

NASA Astrophysics Data System (ADS)

Cosseddu, Piero; Casula, Giulia; Lai, Stefano; Bonfiglio, Annalisa

2015-09-01

The possibility of developing fully organic electronic circuits is critically dependent on the ability to realize a full set of electronic functionalities based on organic devices. In order to complete the scene, a fundamental element is still missing, i.e. reliable data storage. Over the past few years, a considerable effort has been spent on the development and optimization of organic polymer based memory elements. Among several possible solutions, transistor-based memories and resistive switching-based memories are attracting a great interest in the scientific community. In this paper, a route for the fabrication of organic semiconductor-based memory devices with performances beyond the state of the art is reported. Both the families of organic memories will be considered. A flexible resistive memory based on a novel combination of materials is presented. In particular, high retention time in ambient conditions are reported. Complementary, a low voltage transistor-based memory is presented. Low voltage operation is allowed by an hybrid, nano-sized dielectric, which is also responsible for the memory effect in the device. Thanks to the possibility of reproducibly fabricating such device on ultra-thin substrates, high mechanical stability is reported.

Multi-shape memory polymers achieved by the spatio-assembly of 3D printable thermoplastic building blocks.

PubMed

Li, Hongze; Gao, Xiang; Luo, Yingwu

2016-04-07

Multi-shape memory polymers were prepared by the macroscale spatio-assembly of building blocks in this work. The building blocks were methyl acrylate-co-styrene (MA-co-St) copolymers, which have the St-block-(St-random-MA)-block-St tri-block chain sequence. This design ensures that their transition temperatures can be adjusted over a wide range by varying the composition of the middle block. The two St blocks at the chain ends can generate a crosslink network in the final device to achieve strong bonding force between building blocks and the shape memory capacity. Due to their thermoplastic properties, 3D printing was employed for the spatio-assembly to build devices. This method is capable of introducing many transition phases into one device and preparing complicated shapes via 3D printing. The device can perform a complex action via a series of shape changes. Besides, this method can avoid the difficult programing of a series of temporary shapes. The control of intermediate temporary shapes was realized via programing the shapes and locations of building blocks in the final device.

The Effect of Inkjet Printing over Polymeric Films as Potential Buccal Biologics Delivery Systems.

PubMed

Montenegro-Nicolini, Miguel; Reyes, Patricio E; Jara, Miguel O; Vuddanda, Parameswara R; Neira-Carrillo, Andrónico; Butto, Nicole; Velaga, Sitaram; Morales, Javier O

2018-06-22

The buccal mucosa appears as a promissory route for biologic drug administration, and pharmaceutical films are flexible dosage forms that can be used in the buccal mucosa as drug delivery systems for either a local or systemic effect. Recently, thin films have been used as printing substrates to manufacture these dosage forms by inkjet printing. As such, it is necessary to investigate the effects of printing biologics on films as substrates in terms of their physical and mucoadhesive properties. Here, we explored solvent casting as a conventional method with two biocompatible polymers, hydroxypropyl methylcellulose, and chitosan, and we used electrospinning process as an electrospun film fabrication of polycaprolactone fibers due to its potential to elicit mucoadhesion. Lysozyme was used as biologic drug model and was formulated as a solution for printing by thermal inkjet printing. Films were characterized before and after printing by mechanical and mucoadhesive properties, surface, and ultrastructure morphology through scanning electron microscopy and solid state properties by thermal analysis. Although minor differences were detected in micrographs and thermograms in all polymeric films tested, neither mechanical nor mucoadhesive properties were affected by these differences. Thus, biologic drug printing on films was successful without affecting their mechanical or mucoadhesive properties. These results open way to explore biologics loading on buccal films by inkjet printing, and future efforts will include further in vitro and in vivo evaluations.

MR imaging of magnetic ink patterns via off-resonance sensitivity.

PubMed

Perkins, Stephanie L; Daniel, Bruce L; Hargreaves, Brian A

2018-03-30

Printed magnetic ink creates predictable B 0 field perturbations based on printed shape and magnetic susceptibility. This can be exploited for contrast in MR imaging techniques that are sensitized to off-resonance. The purpose of this work was to characterize the susceptibility variations of magnetic ink and demonstrate its application for creating MR-visible skin markings. The magnetic susceptibility of the ink was estimated by comparing acquired and simulated B 0 field maps of a custom-built phantom. The phantom was also imaged using a 3D gradient echo sequence with a presaturation pulse tuned to different frequencies, which adjusts the range of suppressed frequencies. Healthy volunteers with a magnetic ink pattern pressed to the skin or magnetic ink temporary flexible adhesives applied to the skin were similarly imaged. The volume-average magnetic susceptibility of the ink was estimated to be 131 ± 3 parts per million across a 1-mm isotropic voxel (13,100 parts per million assuming a 10-μm thickness of printed ink). Adjusting the saturation frequency highlights different off-resonant regions created by the ink patterns; for example, if tuned to suppress fat, fat suppression will fail near the ink due to the off-resonance. This causes magnetic ink skin markings placed over a region with underlying subcutaneous fat to be visible on MR images. Patterns printed with magnetic ink can be imaged and identified with MRI. Temporary flexible skin adhesives printed with magnetic ink have the potential to be used as skin markings that are visible both by eye and on MR images. © 2018 International Society for Magnetic Resonance in Medicine.

The research on surface characteristics of optical lens by 3D printing technique and precise diamond turning technique

NASA Astrophysics Data System (ADS)

Huang, Chien-Yao; Chang, Chun-Ming; Ho, Cheng-Fong; Lee, Tai-Wen; Lin, Ping-Hung; Hsu, Wei-Yao

2017-06-01

The advantage of 3D printing technique is flexible in design and fabrication. Using 3D printing technique, the traditional manufacturing limitations are not considered. The optical lens is the key component in an optical system. The traditional process to manufacture optical plastic lens is injection molding. However injection molding is only suitable for plastics lens, it cannot fabricate optical and mechanical components at same time. The assembly error of optical system can be reduced effectively with fabricating optical and mechanical components at same time. The process of printing optical and mechanical components simultaneously is proposed in previous papers, but the optical surface of printing components is not transparent. If we increase the transmittance of the optical surface, the printing components which fabricated by 3D printing process could be high transmission. Therefore, precise diamond turning technique has been used to turning the surface of 3D printing optical lens in this paper. The precise diamond turning techniques could process surfaces of components to meet the requirements of optical system. A 3D printing machine, Stratasys Connex 500, and a precise diamond turning machine, Precitech Freeform705XG, have been used in this paper, respectively. The dimension, roughness, transmission and printing types of 3D printing components have been discussed in this paper. After turning and polishing process, the roughness of 3D printing component is below 0.05 μm and the transmittance increase above 80 %. This optical module can be used in hand-held telescope and other system which need lens and special mechanical structure fabricated simultaneously.

Novel Materials for 3D Printing by Photopolymerization.

PubMed

Layani, Michael; Wang, Xiaofeng; Magdassi, Shlomo

2018-05-13

The field of 3D printing, also known as additive manufacturing (AM), is developing rapidly in both academic and industrial research environments. New materials and printing technologies, which enable rapid and multimaterial printing, have given rise to new applications and utilizations. However, the main bottleneck for achieving many more applications is the lack of materials with new physical properties. Here, some of the recent reports on novel materials in this field, such as ceramics, glass, shape-memory polymers, and electronics, are reviewed. Although new materials have been reported for all three main printing approaches-fused deposition modeling, binder jetting or laser sintering/melting, and photopolymerization-based approaches, apparently, most of the novel physicochemical properties are associated with materials printed by photopolymerization approaches. Furthermore, the high resolution that can be achieved using this type of 3D printing, together with the new properties, has resulted in new implementations such as microfluidic, biomedical devices, and soft robotics. Therefore, the focus here is on photopolymerization-based additive manufacturing including the recent development of new methods, novel monomers, and photoinitiators, which result in previously inaccessible applications such as complex ceramic structures, embedded electronics, and responsive 3D objects. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fractal dendrite-based electrically conductive composites for laser-scribed flexible circuits

PubMed Central

Yang, Cheng; Cui, Xiaoya; Zhang, Zhexu; Chiang, Sum Wai; Lin, Wei; Duan, Huan; Li, Jia; Kang, Feiyu; Wong, Ching-Ping

2015-01-01

Fractal metallic dendrites have been drawing more attentions recently, yet they have rarely been explored in electronic printing or packaging applications because of the great challenges in large-scale synthesis and limited understanding in such applications. Here we demonstrate a controllable synthesis of fractal Ag micro-dendrites at the hundred-gram scale. When used as the fillers for isotropically electrically conductive composites (ECCs), the unique three-dimensional fractal geometrical configuration and low-temperature sintering characteristic render the Ag micro dendrites with an ultra-low electrical percolation threshold of 0.97 vol% (8 wt%). The ultra-low percolation threshold and self-limited fusing ability may address some critical challenges in current interconnect technology for microelectronics. For example, only half of the laser-scribe energy is needed to pattern fine circuit lines printed using the present ECCs, showing great potential for wiring ultrathin circuits for high performance flexible electronics. PMID:26333352

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewani, Aliya A., E-mail: a.ashraf@griffith.edu.au; O’Keefe, Steven G.; Thiel, David V.

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substratemore » thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.« less

Surface-enhanced Raman scattering from graphene covered gold nanocap arrays

NASA Astrophysics Data System (ADS)

Long, Kailin; Luo, Xiaoguang; Nan, Haiyan; Du, Deyang; Zhao, Weiwei; Ni, Zhenhua; Qiu, Teng

2013-11-01

This work reports an efficient method to fabricate large-area flexible substrates for surface enhanced Raman scattering (SERS) application. Our technique is based on a single-step direct imprint process via porous anodic alumina stamps. Periodic hexagonal arrangements of porous anodic alumina stamps are transferred to the polyethylene terephthalate substrates by mechanically printing process. Printed nanocaps will turn into "hot spots" for electromagnetic enhancement with a deposited gold film by high vacuum evaporation. The gaps between the nanocaps are controllable with a tight correspondence to the thickness of the deposited gold, which dramatically influence the enhancement factor. After covered with a single-layer graphene sheet, the gold nanocap substrate can be further optimized with an extra enhancement of Raman signals, and it is available for the trace detection of probe molecules. This convenient, simple, and low-cost method of making flexible SERS-active substrates potentially opens a way towards biochemical analysis and disease detection.

Reduction and elimination of format effects on recall.

PubMed

Goolkasian, Paula; Foos, Paul W; Krusemark, Daniel C

2008-01-01

Two experiments investigated whether the recall advantage of pictures and spoken words over printed words in working memory (Foos & Goolkasian, 2005; Goolkasian & Foos, 2002) could be reduced by manipulating letter case and sequential versus simultaneous presentation. Participants were required to remember 3 or 6 items presented in varied presentation formats while verifying the accuracy of a sentence. Presenting words in alternating uppercase and lowercase improved recall, and presenting words simultaneously rather than successively removed the effect of presentation format. The findings suggest that when forcing participants to pay attention to printed words you can make them more memorable and thereby diminish or remove any disadvantage in the recall of printed words in comparison with pictures and spoken words.

Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Dongwoo; Lee, Eonseok; Choi, Young-Man

Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accuratemore » as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.« less

Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems

NASA Astrophysics Data System (ADS)

Kang, Dongwoo; duk Kim, Young; Lee, Eonseok; Choi, Young-Man; Lee, Taik-Min; Kim, Dongmin

2013-12-01

Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accurate as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.

Correlates of Neuropsychological Impairment in Older Adult Pain Clinic Patients

PubMed Central

Karp, Jordan F.; Reynolds, Charles F.; Butters, Meryl; Dew, Mary Amanda; Mazumdar, Sati; Begley, Amy E.; Lenze, Eric; Weiner, Debra K.

2010-01-01

Objective Persistent pain and cognitive impairment are common in older adults. Memory and mental flexibility are cognitive domains which may be vulnerable in the aging brain. We were interested in examining the effects of persistent pain and opioid use on cognition in community dwelling, non-demented older adults. Setting Older Adult Pain Management Program. Design 57 new patients (mean age 76.1) were recruited to describe 1) rates of persistent pain conditions and pain intensity, 2) cognition (memory and mental flexibility), 3) rates and severity of depression, and 4) sleep quality. All patients had non-malignant pain for at least 3 months. Pain intensity was measured with the McGill Pain Questionnaire. Diagnosis of depression was via the Patient Health Questionnaire and depression severity assessed with the Hamilton Rating Scale for Depression. Cognition was assessed with: 1) Mini Mental State Examination, 2) number-letter-switching and motor speed trail-making subtests, 3) Digit Symbol Subtest of the WAIS-R, and 4) free and paired recall of the WAIS-R. To determine which variables predicted poorer outcomes on mental flexibility tests, these variables were entered into a multiple regression. Results Pain severity was associated with impaired number-letter switching (r = −0.42, p = 0.002). Multiple regression showed pain severity was associated with impaired mental flexibility (parameter estimate = −0.29 (t = −2.00), p = 0.05). Patients taking opioids had worse memory (t = 2.17, df = 39, p = 0.04). Conclusions In community-dwelling older adults, pain severity is associated with impaired mental flexibility. In addition, opioids may increase memory problems. PMID:17014605

3D-printing and mechanics of bio-inspired articulated and multi-material structures.

PubMed

Porter, Michael M; Ravikumar, Nakul; Barthelat, Francois; Martini, Roberto

2017-09-01

3D-printing technologies allow researchers to build simplified physical models of complex biological systems to more easily investigate their mechanics. In recent years, a number of 3D-printed structures inspired by the dermal armors of various fishes have been developed to study their multiple mechanical functionalities, including flexible protection, improved hydrodynamics, body support, or tail prehensility. Natural fish armors are generally classified according to their shape, material and structural properties as elasmoid scales, ganoid scales, placoid scales, carapace scutes, or bony plates. Each type of dermal armor forms distinct articulation patterns that facilitate different functional advantages. In this paper, we highlight recent studies that developed 3D-printed structures not only to inform the design and application of some articulated and multi-material structures, but also to explain the mechanics of the natural biological systems they mimic. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabricating nanowire devices on diverse substrates by simple transfer-printing methods.

PubMed

Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

2010-06-01

The fabrication of nanowire (NW) devices on diverse substrates is necessary for applications such as flexible electronics, conformable sensors, and transparent solar cells. Although NWs have been fabricated on plastic and glass by lithographic methods, the choice of device substrates is severely limited by the lithographic process temperature and substrate properties. Here we report three new transfer-printing methods for fabricating NW devices on diverse substrates including polydimethylsiloxane, Petri dishes, Kapton tapes, thermal release tapes, and many types of adhesive tapes. These transfer-printing methods rely on the differences in adhesion to transfer NWs, metal films, and devices from weakly adhesive donor substrates to more strongly adhesive receiver substrates. Electrical characterization of fabricated NW devices shows that reliable ohmic contacts are formed between NWs and electrodes. Moreover, we demonstrated that Si NW devices fabricated by the transfer-printing methods are robust piezoresistive stress sensors and temperature sensors with reliable performance.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred J; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2014-05-13

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John [Champaign, IL; Nuzzo, Ralph [Champaign, IL; Meitl, Matthew [Durham, NC; Menard, Etienne [Durham, NC; Baca, Alfred J [Urbana, IL; Motala, Michael [Champaign, IL; Ahn, Jong-Hyun [Suwon, KR; Park, Sang-II [Savoy, IL; Yu,; Chang-Jae, [Urbana, IL; Ko, Heung-Cho [Gwangju, KR; Stoykovich,; Mark, [Dover, NH; Yoon, Jongseung [Urbana, IL

2011-07-05

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Methodology and technological aspects of the flexible substrate preparation for ink-jet printing technology

NASA Astrophysics Data System (ADS)

Tarapata, Grzegorz; Marzecki, Michał

2013-10-01

The ink-jet printing technology becomes especially promising for wide volume of production of cheap sensors, consumable electronics and other dedicated applications of everyday life like smart packaging, smart textiles, smart labels, etc. To achieve this goal new materials compatible with ink-jet printing should be developed. Currently on the market there is a growing number of inks with different properties, but their use requires many tests related to its printability and their interaction with other materials. The paper presents technological problems that are encountered by people associated with fabrication of various devices with using of inkjet printing techniques. Results presented in the paper show the influence of surface preparation techniques on the quality of achieved shapes, the impact of other materials already deposited and the impact of another external factors. During carried out experiments the printer Dimatix DMP 2831 and several inks base on nanosilver or dielectric UV curable was used.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong -Hyun; Park, Sang -Il; Yu, Chang -Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2015-08-25

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2017-03-21

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Rapid, simple and inexpensive production of custom 3D printed equipment for large-volume fluorescence microscopy

PubMed Central

Tyson, Adam L.; Hilton, Stephen T.; Andreae, Laura C.

2015-01-01

The cost of 3D printing has reduced dramatically over the last few years and is now within reach of many scientific laboratories. This work presents an example of how 3D printing can be applied to the development of custom laboratory equipment that is specifically adapted for use with the novel brain tissue clearing technique, CLARITY. A simple, freely available online software tool was used, along with consumer-grade equipment, to produce a brain slicing chamber and a combined antibody staining and imaging chamber. Using standard 3D printers we were able to produce research-grade parts in an iterative manner at a fraction of the cost of commercial equipment. 3D printing provides a reproducible, flexible, simple and cost-effective method for researchers to produce the equipment needed to quickly adopt new methods. PMID:25797056

Effects of β-hydroxy-β-methyl butyrate on working memory and cognitive flexibility in an animal model of aging.

PubMed

Hankosky, Emily R; Sherrill, Luke K; Ruvola, Lauren A; Haake, Rachel M; Kim, Taehyeon; Hammerslag, Lindsey R; Kougias, Daniel G; Juraska, Janice M; Gulley, Joshua M

2017-09-01

Normal aging results in cognitive decline and nutritional interventions have been suggested as potential approaches for mitigating these deficits. Here, we used rats to investigate the effects of short- and long-term dietary supplementation with the leucine metabolite β-hydroxy-β-methyl butyrate (HMB) on working memory and cognitive flexibility. Beginning ∼12 months of age, male and female Long-Evans rats were given twice daily access to sipper tubes containing calcium HMB (450 mg/kg) or vehicle (285 mg/kg calcium lactate) in a sucrose solution (20% w/v). Supplementation continued for 1 or 7 months (middle- and old-age (OA) groups, respectively) before testing began. Working memory was assessed by requiring rats to respond on a previously sampled lever following various delays. Cognitive flexibility was assessed by training rats to earn food according to a visual strategy and then, once acquired, shifting to an egocentric response strategy. Treatment with HMB improved working memory performance in middle-age (MA) males and OA rats of both sexes. In the cognitive flexibility task, there was a significant age-dependent deficit in acquisition of the visual strategy that was not apparent in OA males treated with HMB. Furthermore, HMB ameliorated an apparent deficit in visual strategy acquisition in MA females. Together, these findings suggest that daily nutritional supplementation with HMB facilitates learning and improves working memory performance. As such, HMB supplementation may mitigate age-related cognitive deficits and may therefore be an effective tool to combat this undesirable feature of the aging process.

System-Level Integration of Mass Memory

NASA Technical Reports Server (NTRS)

Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

2008-01-01

A report discusses integrating multiple memory modules on the high-speed serial interconnect (IEEE 1393) that is used by a spacecraft?s inter-module communications in order to ease data congestion and provide for a scalable, strong, flexible system that can meet new system-level mass memory requirements.

77 FR 58473 - Minimum Technical Standards for Class II Gaming Systems and Equipment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-21

... as printed advertising material that cannot be validated directly by a voucher system. Critical... on that component. EPROM. Erasable Programmable Read Only Memory--a non-volatile storage chip or...

Investigation of the adhesion properties of direct 3D printing of polymers and nanocomposites on textiles: Effect of FDM printing process parameters

NASA Astrophysics Data System (ADS)

Hashemi Sanatgar, Razieh; Campagne, Christine; Nierstrasz, Vincent

2017-05-01

In this paper, 3D printing as a novel printing process was considered for deposition of polymers on synthetic fabrics to introduce more flexible, resource-efficient and cost effective textile functionalization processes than conventional printing process like screen and inkjet printing. The aim is to develop an integrated or tailored production process for smart and functional textiles which avoid unnecessary use of water, energy, chemicals and minimize the waste to improve ecological footprint and productivity. Adhesion of polymer and nanocomposite layers which were 3D printed directly onto the textile fabrics using fused deposition modeling (FDM) technique was investigated. Different variables which may affect the adhesion properties including 3D printing process parameters, fabric type and filler type incorporated in polymer were considered. A rectangular shape according to the peeling standard was designed as 3D computer-aided design (CAD) to find out the effect of the different variables. The polymers were printed in different series of experimental design: nylon on polyamide 66 (PA66) fabrics, polylactic acid (PLA) on PA66 fabric, PLA on PLA fabric, and finally nanosize carbon black/PLA (CB/PLA) and multi-wall carbon nanotubes/PLA (CNT/PLA) nanocomposites on PLA fabrics. The adhesion forces were quantified using the innovative sample preparing method combining with the peeling standard method. Results showed that different variables of 3D printing process like extruder temperature, platform temperature and printing speed can have significant effect on adhesion force of polymers to fabrics while direct 3D printing. A model was proposed specifically for deposition of a commercial 3D printer Nylon filament on PA66 fabrics. In the following, among the printed polymers, PLA and its composites had high adhesion force to PLA fabrics.

Functional neuroimaging correlates of thinking flexibility and knowledge structure in memory: Exploring the relationships between clinical reasoning and diagnostic thinking.

PubMed

Durning, Steven J; Costanzo, Michelle E; Beckman, Thomas J; Artino, Anthony R; Roy, Michael J; van der Vleuten, Cees; Holmboe, Eric S; Lipner, Rebecca S; Schuwirth, Lambert

2016-06-01

Diagnostic reasoning involves the thinking steps up to and including arrival at a diagnosis. Dual process theory posits that a physician's thinking is based on both non-analytic or fast, subconscious thinking and analytic thinking that is slower, more conscious, effortful and characterized by comparing and contrasting alternatives. Expertise in clinical reasoning may relate to the two dimensions measured by the diagnostic thinking inventory (DTI): memory structure and flexibility in thinking. Explored the functional magnetic resonance imaging (fMRI) correlates of these two aspects of the DTI: memory structure and flexibility of thinking. Participants answered and reflected upon multiple-choice questions (MCQs) during fMRI. A DTI was completed shortly after the scan. The brain processes associated with the two dimensions of the DTI were correlated with fMRI phases - assessing flexibility in thinking during analytical clinical reasoning, memory structure during non-analytical clinical reasoning and the total DTI during both non-analytical and analytical reasoning in experienced physicians. Each DTI component was associated with distinct functional neuroanatomic activation patterns, particularly in the prefrontal cortex. Our findings support diagnostic thinking conceptual models and indicate mechanisms through which cognitive demands may induce functional adaptation within the prefrontal cortex. This provides additional objective validity evidence for the use of the DTI in medical education and practice settings.

Media and memory: the efficacy of video and print materials for promoting patient education about asthma.

PubMed

Wilson, Elizabeth A H; Park, Denise C; Curtis, Laura M; Cameron, Kenzie A; Clayman, Marla L; Makoul, Gregory; Vom Eigen, Keith; Wolf, Michael S

2010-09-01

We examined the effects of presentation medium on immediate and delayed recall of information and assessed the effect of giving patients take-home materials after initial presentations. Primary-care patients received video-based, print-based or no asthma education about asthma symptoms and triggers and then answered knowledge-based questions. Print participants and half the video participants received take-home print materials. A week later, available participants completed the knowledge assessment again. Participants receiving either intervention outperformed controls on immediate and delayed assessments (p<0.001). For symptom-related information, immediate performance did not significantly differ between print and video participants. A week later, receiving take-home print predicted better performance (p<0.05), as did self-reported review among recipients of take-home print (p<0.01). For content about inhaler usage, although video watchers outperformed print participants immediately after seeing the materials (p<0.001), a week later these two groups' performance did not significantly differ. Among participants given take-home materials, review predicted marginally better recall (p=0.06). Video and print interventions can promote recall of health-related information. Additionally, reviewable materials, if they are utilized, may improve retention. When creating educational tools, providers should consider how long information must be retained, its content, and the feasibility of providing tangible supporting materials. Copyright (c) 2010. Published by Elsevier Ireland Ltd.

An innovative design for using flexible printed coils for magnetostrictive-based longitudinal guided wave sensors in steel strand inspection

NASA Astrophysics Data System (ADS)

Tse, P. W.; Liu, X. C.; Liu, Z. H.; Wu, B.; He, C. F.; Wang, X. J.

2011-05-01

Magnetostrictive sensors (MsSs) that can excite and receive guided waves are commonly used in detecting defects that may occur in cables and strands for supporting heavy structures. A conventional MsS has a hard sensing coil that is wound onto a bobbin with electric wires to generate the necessary dynamic magnetic field to excite the desired guided waves. This tailor-made hard coil is usually bulky and is not flexible enough to fit steel strands of various sizes. The conventional MsS also cannot be mounted to any steel strand that does not have a free end to allow the bobbin to pass through the structure of the tested strand. Such inflexibilities limit the use of conventional MsSs in practical situations. To solve these limitations, an innovative type of coil, called a flexible printed coil (FPC), which is made out of flexible printed film, has been designed to replace the inflexible hard coil. The flexible structure of the FPC ensures that the new MsS can be easily installed on and removed from steel strands with different diameters and without free ends. Moreover, the FPC-based MsS can be wrapped into multiple layers due to its thin and flexible design. Although multi-layer FPC creates a minor asymmetry in the dynamic magnetic field, the results of finite element analysis and experiments confirm that the longitudinal guided waves excited by a FPC-based MsS are comparable to those excited by a conventional hard coil MsS. No significant reduction in defect inspection performance was found; in fact, further advantages were identified when using the FPC-based MsS. When acting as the transmitter, the innovative FPC-based MsS can cover a longer inspection length of strand. When acting as the receiver, the FPC-based MsS is more sensitive to smaller defects that are impossible to detect using a hard coil MsS. Hence, the multi-layer FPC-based MsS has great potential for replacing the conventional hard coil MsS because of its convenient installation, and ease of fitting to different strand diameters; it is smaller, and, most importantly, performs much better in strand defect detection.

Printed stretchable circuit on soft elastic substrate for wearable application

NASA Astrophysics Data System (ADS)

Yuan, Wei; Wu, Xinzhou; Gu, Weibing; Lin, Jian; Cui, Zheng

2018-01-01

In this paper, a flexible and stretchable circuit has been fabricated by the printing method based on Ag NWs/PDMS composite. The randomly oriented Ag NWs were buried in PDMS to form a conductive and stretchable electrode. Stable conductivity was achieved with a large range of tensile strain (0-50%) after the initial stretching/releasing cycle. The stable electrical response is due to the buckling of the Ag NWs/PDMS composite layer. Furthermore, printed stretchable circuits integrated with commercial ICs have been demonstrated for wearable applications. Project supported by the National Program on Key Basic Research Project (No. 2015CB351901), the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA09020201), and the National Science Foundation of China (Nos. 51603227, 51603228).

Inkjet printing for biosensor fabrication: combining chemistry and technology for advanced manufacturing.

PubMed

Li, Jia; Rossignol, Fabrice; Macdonald, Joanne

2015-06-21

Inkjet printing is emerging at the forefront of biosensor fabrication technologies. Parallel advances in both ink chemistry and printers have led to a biosensor manufacturing approach that is simple, rapid, flexible, high resolution, low cost, efficient for mass production, and extends the capabilities of devices beyond other manufacturing technologies. Here we review for the first time the factors behind successful inkjet biosensor fabrication, including printers, inks, patterning methods, and matrix types. We discuss technical considerations that are important when moving beyond theoretical knowledge to practical implementation. We also highlight significant advances in biosensor functionality that have been realised through inkjet printing. Finally, we consider future possibilities for biosensors enabled by this novel combination of chemistry and technology.

Influence of the UV radiation on the screen-printed pH-sensitive layers based on graphene and ruthenium dioxide

NASA Astrophysics Data System (ADS)

Pepłowski, A.; Grudziński, D.; Raczyński, T.; Wróblewski, G.; Janczak, D.; Jakubowska, M.

2017-08-01

Electrodes for measuring pH of the solution were fabricated by the means of screen-printing technology. Potentiometric sensors' layers comprised of composite with polymer matrix and graphene nanoplatelets/ruthenium (IV) oxide nanopowder as functional phase. Transceivers were printed on the elastic PMMA foil. Regarding potential application of the sensors in the wearable devices, dynamic response of the electrodes to changing ultraviolet radiation levels was assessed, since RuO2 is reported to be UV-sensitive. Observed changes of the electrodes' potential were of sub-millivolt magnitude, being comparable to simultaneously observed signal drift. Given this stability under varying UV conditions and previously verified good flexibility, fabricated sensors meet the requirements for wearable applications.