Science.gov

Sample records for flexible covered metallic

  1. Palliation of Postoperative Gastrointestinal Anastomotic Malignant Strictures with Flexible Covered Metallic Stents: Preliminary Results

    SciTech Connect

    Lee, Jeong-Min; Han, Young Min; Lee, Sang Yong; Kim, Chong Soo; Yang, Doo Hyun; Lee, Seung Ok

    2001-01-15

    Purpose: To evaluate the efficacy of the placement of covered metallic stents for palliation of gastrointestinal anastomotic strictures secondary to recurrent gastric cancer.Methods: Under fluoroscopic guidance, placement of one or two self-expandable covered metallic stents was attempted perorally in 11 patents (aged 48-76 years) with anastomotic stenoses due to recurrent gastric malignancies. The strictures involved both the afferent and efferent loops in three patients. All patients had poor peroral food intake with severe nausea and vomiting after ingestion. The technical and clinical success was evaluated.Results: Placement of the covered stent was technically successful in 13 of 15 (87%) attempts in ten patients. After the procedure, 9 of 11 (82%) patients overall were able to ingest at least a liquid diet and had markedly decreased incidence of vomiting. During the follow-up of 2-31 weeks (mean 8.5 weeks) there were no major complications.Conclusion: These preliminary results suggest that flexible, covered stents may provide effective palliation of malignant anastomotic stricture secondary to recurrent gastric cancer.

  2. Development of a resettable, flexible aperture cover

    NASA Technical Reports Server (NTRS)

    Christiansen, Scott

    1992-01-01

    A flexible aperture cover and latch were developed for the Thermal Ion Detection Experiment (TIDE). The latch utilized a high-output paraffin (HOP) linear motor to supply the force to operate the latch. The initial approach for the cover was to use a heat-treated, coiled strip of 0.05 mm (.002-inch)-thick beryllium-copper as the cover. Development test results showed that one end of the cover developed a trajectory during release that threatened to impact against adjacent instruments. An alternative design utilizing constant force springs and a flexible, metallized Kapton cover was then tested. Results from development tests, microgravity tests, and lessons learned during the development of the aperture cover are discussed.

  3. Flexible protection for metal bellows

    NASA Technical Reports Server (NTRS)

    Kimble, K. G.

    1970-01-01

    RTV silicone is used with a braided wire sheath surrounding the metal bellows in fluid transfer systems. It demonstrated best overall performance in flexibility and shock absorbing tests, high temperature, low temperature, and salt spray.

  4. Flexible Metal-Fabric Radiators

    NASA Technical Reports Server (NTRS)

    Cross, Cynthia; Nguyen, Hai D.; Ruemmele, Warren; Andish, Kambiz K.; McCalley, Sean

    2005-01-01

    Flexible metal-fabric radiators have been considered as alternative means of dissipating excess heat from spacecraft and space suits. The radiators also may be useful in such special terrestrial applications as rejecting heat from space-suit-like protective suits worn in hot work environments. In addition to flexibility and consequent ease of deployment and installation on objects of varying sizes and shapes, the main advantages of these radiators over conventional rigid radiators are that they weigh less and occupy less volume for a given amount of cooling capacity. A radiator of this type includes conventional stainless-steel tubes carrying a coolant fluid. The main radiating component consists of a fabric of interwoven aluminum-foil strips bonded to the tubes by use of a proprietary process. The strip/tube bonds are strong and highly thermally conductive. Coolant is fed to and from the tubes via flexible stainless-steel manifolds designed to accommodate flexing of, and minimize bending forces on, the fabric. The manifolds are sized to minimize pressure drops and distribute the flow of coolant evenly to all the tubes. The tubes and manifolds are configured in two independent flow loops for operational flexibility and protective redundancy.

  5. Flexible thin metal film thermal sensing system

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald L. (Inventor)

    2010-01-01

    A flexible thin metal film thermal sensing system is provided. A self-metallized polymeric film has a polymeric film region and a metal surface disposed thereon. A layer of electrically-conductive metal is deposited directly onto the self-metallized polymeric film's metal surface. Coupled to at least one of the metal surface and the layer of electrically-conductive metal is a device/system for measuring an electrical characteristic associated therewith as an indication of temperature.

  6. Flexible, Polymer-Filled Metallic Conductors

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Swec, Diane M.

    1989-01-01

    Procedure developed to make materials both flexible and reasonably good electrical conductors. Metal or polymer sheet substrate cleaned with beam of energetic inert-gas ions to remove adsorbed gases and contaminants from surface. After cleaning, substrate coated by cosputter deposition of both conductive metal and flexible polymer. Removed by either mechanical or chemical-dissolution technique, and resulting flexible metal/polymer conductor bonded at low temperature to conductor-surface contacts.

  7. Flexible, Polymer-Filled Metallic Conductors

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Swec, Diane M.

    1989-01-01

    Procedure developed to make materials both flexible and reasonably good electrical conductors. Metal or polymer sheet substrate cleaned with beam of energetic inert-gas ions to remove adsorbed gases and contaminants from surface. After cleaning, substrate coated by cosputter deposition of both conductive metal and flexible polymer. Removed by either mechanical or chemical-dissolution technique, and resulting flexible metal/polymer conductor bonded at low temperature to conductor-surface contacts.

  8. Flexible Ceramic-Metal Insulation Composite and Method of Making

    NASA Technical Reports Server (NTRS)

    Rasky, Daniel J. (Inventor); Sawko, Paul M. (Inventor); Kilodziej, Paul (Inventor); Kourtides, Demetrius A. (Inventor)

    1998-01-01

    A method for joining a woven flexible ceramic fabric and a thin metal sheet creating an integral metal surfaced flexible thermal protection article, which methods compress: placing multiple dots of high temperature metallic or fabric and the thin metal sheet in a random or organized pattern, with the proviso that the brazing material covers about 10% or less of the surface of one flat side of the metal sheet; heating the flexible ceramic fabric, brazing material and thin metal sheet for a predetermined period of time to integrally connect the same; and cooling the formed flexible article to ambient temperature. Preferably the flexible ceramic is selected from fibers comprising atoms of silicon, carbon, nitrogen, boron, oxygen or combinations thereof. The flexible thermal protection article produced is also part of the present invention. The thin metal sheet is comprised of titanium, aluminum, chromium, niobium or alloys or combinations thereof. The brazing material is selected from copper/silver or copper/gold or is a ceramic brazing or adhesive material.

  9. Flexible Thin Metal Film Thermal Sensing System

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald Laurence (Inventor)

    2012-01-01

    A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

  10. Covering a Crucible with Metal Containing Channels

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.

    2006-01-01

    In a procedure that partly resembles the lost-wax casting process, a crucible made of a brittle material (ceramic, quartz, or glass) is covered with a layer of metal containing channels. The metal cover and the channels can serve any or all of several purposes, depending upon the application: Typically, the metal would serve at least partly to reinforce the crucible. The channels could be used as passages for narrow objects that could include thermocouples and heat-transfer strips. Alternatively or in addition, channels could be used as flow paths for liquid or gaseous coolants and could be positioned and oriented for position- or direction-selective cooling. In some cases, the channels could be filled with known gases and sealed so that failure of the crucibles could be indicated by instruments that detect the gases. The process consists of three main steps. In the first step, a pattern defining the channels is formed by wrapping or depositing a material in the desired channel pattern on the outer surface of the crucible. The pattern material can be a plastic, wax, low-ash fibrous material, a soluble material, or other suitable material that can subsequently be removed easily. In a proof-of-concept demonstration (see figure), the crucible was an alumina cylinder and the mold material was plastic tie-down tape. In the second step, the patterned crucible is coated with metal. In one variation of the second step, a very thin layer containing or consisting of an electrically conductive material (e.g., gold, silver, or carbon) is painted or otherwise deposited on the mold-covered crucible, then the covering metal required for the specific application is electrodeposited on the very thin conducting layer. In another variation of the second step, the metal coat is formed by chemical vapor deposition. In the proof-of-concept demonstration, a layer of nickel 0.003 in. ( 0.08 mm) thick was electrodeposited. In the third step, the patterned material is removed. This is

  11. Flexible amorphous metal films with high stability

    NASA Astrophysics Data System (ADS)

    Liu, M.; Cao, C. R.; Lu, Y. M.; Wang, W. H.; Bai, H. Y.

    2017-01-01

    We report the formation of amorphous Cu50Zr50 films with a large-area of more than 100 cm2. The films were fabricated by ion beam assisted deposition with a slow deposition rate at moderate temperature. The amorphous films have markedly enhanced thermal stability, excellent flexibility, and high reflectivity with atomic level smoothness. The multifunctional properties of the amorphous films are favorites in the promising applications of smart skin or wearable devices. The method of preparing highly stable amorphous metal films by tuning the deposition rate instead of deposition temperature could pave a way for exploring amorphous metal films with unique properties.

  12. Flexibility and Stability of Metal Coordination Macromolecules.

    PubMed

    Jiang, Heyan; Geng, Diya; Liu, Dapeng; Lanigan, Nicholas; Wang, Xiaosong

    2017-06-16

    The effect of chain structure on flexibility and stability of macromolecules containing weak P-Fe metal coordination bonds is studied. Migration insertion polymerization (MIP) of FpCX Fp (1) and PR2 CY PR2 (2) (Fp: CpFe(CO)2 ; CX and CY : alkyl spacers; P: phosphine; R: phenyl or isopropyl) generates P(1/2), in which the P-Fe and Fe-P bonds with opposite bonding direction are alternatively arranged in the backbone. On the other hand, P(FpCX P) synthesized from AB-type monomers (FpCX P) has P-Fe bonds arranged in the same direction. P(1/2) is more rigid and stable than P(FpCX P), which is attributed to the chain conformation resulting from the P-Fe bonding direction. In addition, the longer spacers render P(1/2) relatively flexible; the phenyl substituents, as compared with the isopropyl groups, improves the rigidity, thermal, and solution stability of P(1/2). It is therefore possible to incorporate weak metal coordination bonds into macromolecules with improved stability and adjustable flexibility for material processing. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Metal substrate based electrodes for flexible dye-sensitized solar cells: fabrication methods, progress and challenges.

    PubMed

    Balasingam, Suresh Kannan; Kang, Man Gu; Jun, Yongseok

    2013-12-21

    A step towards commercialization of dye-sensitized solar cells (DSSCs) requires more attention to engineering aspects, such as flexibility, the roll to roll fabrication process, the use of cost effective materials, etc. In this aspect, advantages of flexible DSSCs attracted many researchers to contemplate the transparent conducting oxide coated flexible plastic substrates and the thin metallic foils. In this feature article, the pros and cons of these two kinds of substrates are compared. The flexible dye-sensitized solar cells fabricated using metal substrates are briefly discussed. The working electrodes of DSSCs fabricated on various metal substrates, their fabrication methods, the effect of high temperature calcination and drawbacks of back illumination are reviewed in detail. A few reports on the flexible metal substrate based counter electrodes that could be combined with the plastic substrate based working electrodes are also covered at the end.

  14. Programmable Metallization Cell Devices for Flexible Electronics

    NASA Astrophysics Data System (ADS)

    Baliga, Sunil

    Programmable metallization cell (PMC) technology is based on an electrochemical phenomenon in which a metallic electrodeposit can be grown or dissolved between two electrodes depending on the voltage applied between them. Devices based on this phenomenon exhibit a unique, self-healing property, as a broken metallic structure can be healed by applying an appropriate voltage between the two broken ends. This work explores methods of fabricating interconnects and switches based on PMC technology on flexible substrates. The objective was the evaluation of the feasibility of using this technology in flexible electronics applications in which reliability is a primary concern. The re-healable property of the interconnect is characterized for the silver doped germanium selenide (Ag-Ge-Se) solid electrolyte system. This property was evaluated by measuring the resistances of the healed interconnect structures and comparing these to the resistances of the unbroken structures. The reliability of the interconnects in both unbroken and healed states is studied by investigating the resistances of the structures to DC voltages, AC voltages and different temperatures as a function of time. This work also explores replacing silver with copper for these interconnects to enhance their reliability. A model for PMC-based switches on flexible substrates is proposed and compared to the observed device behavior with the objective of developing a formal design methodology for these devices. The switches were subjected to voltage sweeps and their resistance was investigated as a function of sweep voltage. The resistance of the switches as a function of voltage pulse magnitude when placed in series with a resistance was also investigated. A model was then developed to explain the behavior of these devices. All observations were based on statistical measurements to account for random errors. The results of this work demonstrate that solid electrolyte based interconnects display self

  15. Flexible transparent conductors based on metal nanowire networks

    DOE PAGES

    Guo, Chuan Fei; Ren, Zhifeng

    2015-04-01

    Few conductors are transparent and flexible. Metals have the best electrical conductivity, but they are opaque and stiff in bulk form. However, metals can be transparent and flexible when they are very thin or properly arranged on the nanoscale. This review focuses on the flexible transparent conductors based on percolating networks of metal. Specifically, we discuss the fabrication, the means to improve the electrical conductivity, the large stretchability and its mechanism, and the applications of these metal networks. We also suggest some criteria for evaluating flexible transparent conductors and propose some new research directions in this emerging field.

  16. Treatment of a malignant esophageal fistula with a Gore-Tex-covered flexible nitinol stent

    SciTech Connect

    Kishi, Kazushi; Takeuchi, Taizo; Sonomura, Tetsuo; Kimura, Masashi; Kita, Keisuke; Sato, Morio; Terada, Masaki

    1997-01-15

    In order to treat fistulated esophageal cancer using a flexible stent, a covered flexible stent was constructed by wrapping a nitinol stent with a thin sheet of Gore-Tex, preserving the stents original advantages of flexibility and a low-profile introducer system. This stent was used to perform standard radiotherapy in a case of fistulated esophageal cancer.

  17. Mechanical Sensing with Flexible Metallic Nanowires

    NASA Astrophysics Data System (ADS)

    Dobrokhotov, Vladimir; Yazdanpanah, Mehdi; Pabba, Santosh; Safir, Abdelilah; Cohn, Robert

    2008-03-01

    A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire is interpreted to determine the applied force. Using a nanomanipulator the nanowire is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model. In this calibration the elastic modulus was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.

  18. Flexible germanium nanomembrane metal-semiconductor-metal photodiodes

    SciTech Connect

    Kim, Munho; Seo, Jung-Hun; Yu, Zongfu; Ma, Zhenqiang; Zhou, Weidong

    2016-08-01

    We demonstrate flexible Ge nanomembrane (Ge NM) based metal-semiconductor-metal photodiodes. The effect of uniaxial tensile strain on Ge NM based photodiodes was investigated using bending fixtures. Dark current density is decreased from 21.5 to 4.8 mA/cm{sup 2} at 3 V by a tensile strain of 0.42% while photon responsivity is increased from 0.2 to 0.45 A/W at the wavelength of 1.5 μm. Enhanced responsivity is also observed at longer wavelengths up to 1.64 μm. The uniaxial tensile strain effectively reduces the direct bandgap energy of the Ge NM, leading to a shift of the absorption edge toward a longer wavelength.

  19. Progress in development of flexible metal-air batteries

    NASA Astrophysics Data System (ADS)

    Sumboja, Afriyanti; Ge, Xiaoming; Zong, Yun; Liu, Zhaolin

    2016-04-01

    Flexible electronics has gained great interest in emerging wearable or rolling-up gadgets, such as foldable displays, electronic papers, and other personal multimedia devices. Subsequently, there is a need to develop energy storage devices that are pliable, inexpensive, and lightweight. Metal-air batteries have been identified as one of alternative energy storages for cost effective and high energy density applications. They offer cheaper production cost and higher energy density than most of the currently available battery technologies. Thus, they are promising candidates for flexible energy storage devices. Flexible metal-air batteries have to maintain their performances during various mechanical deformations. To date, efforts have been focused on fabricating flexible components for metal-air batteries. This review presents a brief introduction to the field, followed by progress on development of flexible electrolytes, electrodes, and prototype devices. Challenges and outlook towards the practical use of metal-air batteries are given in the last part.

  20. 75 FR 49527 - Metaldyne Corporation, Metaldyne Tubular Products, Currently Known as Flexible Metal, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Flexible Metal, Inc., Powertrain Division, Hamburg, MI; Amended Certification Regarding Eligibility To... automotive industry. Information shows that on June 10, 2010, Flexible Metals, Inc. purchased Metaldyne Corporation, Metaldyne Tubular Products, Powertrain Div. and is currently known as Flexible Metals, Inc...

  1. Flexible Transition Metal Oxide Electronics and Imprint Lithography

    NASA Astrophysics Data System (ADS)

    Jackson, Warren B.

    The previous chapters have discussed inorganic low-deposition temperature materials suitable for flexible applications, such as amorphous and nano-crystalline-silicon (Si) and organic conductors. This chapter presents the results of a recently developed inorganic low-temperature materials system, transition metal oxides (TMOs), that appears to be a very promising, new high-performance flexible electronic materials system. An equally, if not more, important part of this chapter, is the presentation of self-aligned imprint lithography (SAIL) a new fabrication method for flexible substrates that solves the layer-to-layer alignment problem.

  2. Metal oxide semiconductor thin-film transistors for flexible electronics

    SciTech Connect

    Petti, Luisa; Vogt, Christian; Büthe, Lars; Cantarella, Giuseppe; Tröster, Gerhard; Münzenrieder, Niko; Faber, Hendrik; Bottacchi, Francesca; Anthopoulos, Thomas D.

    2016-06-15

    The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This review reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular

  3. Metal oxide semiconductor thin-film transistors for flexible electronics

    NASA Astrophysics Data System (ADS)

    Petti, Luisa; Münzenrieder, Niko; Vogt, Christian; Faber, Hendrik; Büthe, Lars; Cantarella, Giuseppe; Bottacchi, Francesca; Anthopoulos, Thomas D.; Tröster, Gerhard

    2016-06-01

    The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This review reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular

  4. Flexible macrocycles as versatile supports for catalytically active metal clusters

    DOE PAGES

    Ryan, Jason D.; Gagnon, Kevin J.; Teat, Simon J.; ...

    2016-02-12

    Here we present three structurally diverse clusters stabilised by the same macrocyclic polyphenol; t-butylcalix[8]arene. This work demonstrates the range of conformations the flexible ligand is capable of adopting, highlighting its versatility in metal coordination. In addition, a Ti complex displays activity for the ring-opening polymerisation of lactide

  5. Flexible macrocycles as versatile supports for catalytically active metal clusters

    SciTech Connect

    Ryan, Jason D.; Gagnon, Kevin J.; Teat, Simon J.; McIntosh, Ruaraidh D.

    2016-02-12

    Here we present three structurally diverse clusters stabilised by the same macrocyclic polyphenol; t-butylcalix[8]arene. This work demonstrates the range of conformations the flexible ligand is capable of adopting, highlighting its versatility in metal coordination. In addition, a Ti complex displays activity for the ring-opening polymerisation of lactide

  6. Iron-copper metallization for flexible solar/cell arrays

    NASA Technical Reports Server (NTRS)

    Lavendel, H. W.

    1983-01-01

    The feasibility of a copper-base metallization for shallow-junction cells applied in flexible solar arrays in space is discussed. This type of metallization will reduce usage of precious metals (such as silver), increase case of bonding (by welding or by soldering) and eliminate heavy high Z interconnects (such as molybdenum). The main points of concern are stability against thermally induced diffusion of copper into silicon which causes degradation of shallow cell junctions, and low series resistance of the contact with semiconductor which promotes cell efficiency.

  7. Flexible and transparent metallic grid electrodes prepared by evaporative assembly.

    PubMed

    Park, Jae Hoon; Lee, Dong Yun; Kim, Young-Hoon; Kim, Jung Kyu; Lee, Jung Heon; Park, Jong Hyeok; Lee, Tae-Woo; Cho, Jeong Ho

    2014-08-13

    We propose a novel approach to fabricating flexible transparent metallic grid electrodes via evaporative deposition involving flow-coating. A transparent flexible metal grid electrode was fabricated through four essential steps including: (i) polymer line pattern formation on the thermally evaporated metal layer onto a plastic substrate; (ii) rotation of the stage by 90° and the formation of the second polymer line pattern; (iii) etching of the unprotected metal region; and (iv) removal of the residual polymer from the metal grid pattern. Both the metal grid width and the spacing were systematically controlled by varying the concentration of the polymer solution and the moving distance between intermittent stop times of the polymer blade. The optimized Au grid electrodes exhibited an optical transmittance of 92% at 550 nm and a sheet resistance of 97 Ω/sq. The resulting metallic grid electrodes were successfully applied to various organic electronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic solar cells (OSCs).

  8. Exploratory development of a flexible ablative covering for space shuttle application

    NASA Technical Reports Server (NTRS)

    Hiltz, A. A.

    1972-01-01

    An applied research program is considered for a preliminary design and development of a flexible ablative covering for the space shuttle vehicle that could be easily replaced and/or refurbished. The program was structured to concentrate resources on the major technical problem areas associated with the flexible ablator concept. These areas included: (1) fabrication of a suitable woven carpet reinforcement, (2) modification of a flexible ablator formulation for filling the woven carpet construction, and (3) testing of the flexible ablator concept. Several approaches were evaluated to obtain a flexible ablator. The final recommended solution was one in which the ablative filler was based on a low-density formulation of the elastomeric shield material series (ESM). The preferred approach is one in which a light-weight fabric backing is bonded to preformed and fully cured ESM, and the composite tufted with Astroquartz fiber to the desired tuft or pile density. Ablation tests performed in a hyperthermal arc facility demonstrated the ablation performance of the concept and overshoot capability of the system.

  9. Integration of Metal Oxide Nanowires in Flexible Gas Sensing Devices

    PubMed Central

    Comini, Elisabetta

    2013-01-01

    Metal oxide nanowires are very promising active materials for different applications, especially in the field of gas sensors. Advances in fabrication technologies now allow the preparation of nanowires on flexible substrates, expanding the potential market of the resulting sensors. The critical steps for the large-scale preparation of reliable sensing devices are the elimination of high temperatures processes and the stretchability of the entire final device, including the active material. Direct growth on flexible substrates and post-growth procedures have been successfully used for the preparation of gas sensors. The paper will summarize the procedures used for the preparation of flexible and wearable gas sensors prototypes with an overlook of the challenges and the future perspectives concerning this field. PMID:23955436

  10. Amending metal contaminated mine soil with biochars to sequester metals and improve plant growth cover

    EPA Science Inventory

    There are numerous mine spoil sites in the U.S. Pacific Northwest that contain highly acidic, heavy metal-laden soils, which limits establishment of a soil-stabilizing plant cover. Biochars may be a suitable soil amendment to reduce toxic metals, improve soil fertility, soil wa...

  11. Amending metal contaminated mine soil with biochars to sequester metals and improve plant growth cover

    EPA Science Inventory

    There are numerous mine spoil sites in the U.S. Pacific Northwest that contain highly acidic, heavy metal-laden soils, which limits establishment of a soil-stabilizing plant cover. Biochars may be a suitable soil amendment to reduce toxic metals, improve soil fertility, soil wa...

  12. Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Marrs, Michael

    A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors. Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors. Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs

  13. Polymer-metal hybrid transparent electrodes for flexible electronics

    PubMed Central

    Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

    2015-01-01

    Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of ‘polymer-metal hybrid electrodes’ with high-performance properties, including a bending radius <1 mm, a visible-range transmittance>95% and a sheet resistance <10 Ω sq−1. These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides. PMID:25790133

  14. Polymer-metal hybrid transparent electrodes for flexible electronics

    NASA Astrophysics Data System (ADS)

    Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

    2015-03-01

    Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of ‘polymer-metal hybrid electrodes’ with high-performance properties, including a bending radius <1 mm, a visible-range transmittance>95% and a sheet resistance <10 Ω sq-1. These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides.

  15. Polymer-metal hybrid transparent electrodes for flexible electronics.

    PubMed

    Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

    2015-03-19

    Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of 'polymer-metal hybrid electrodes' with high-performance properties, including a bending radius <1 mm, a visible-range transmittance>95% and a sheet resistance <10 Ω sq(-1). These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides.

  16. Asymmetric Pentagonal Metal Meshes for Flexible Transparent Electrodes and Heaters.

    PubMed

    Lordan, Daniel; Burke, Micheal; Manning, Mary; Martin, Alfonso; Amann, Andreas; O'Connell, Dan; Murphy, Richard; Lyons, Colin; Quinn, Aidan J

    2017-02-08

    Metal meshes have emerged as an important class of flexible transparent electrodes. We report on the characteristics of a new class of asymmetric meshes, tiled using a recently discovered family of pentagons. Micron-scale meshes were fabricated on flexible polyethylene terephthalate substrates via optical lithography, metal evaporation (Ti 10 nm, Pt 50 nm), and lift-off. Three different designs were assessed, each with the same tessellation pattern and line width (5 μm), but with different sizes of the fundamental pentagonal unit. Good mechanical stability was observed for both tensile strain and compressive strain. After 1000 bending cycles, devices subjected to tensile strain showed fractional resistance increases in the range of 8-17%, while devices subjected to compressive strain showed fractional resistance increases in the range of 0-7%. The performance of the pentagonal metal mesh devices as visible transparent heaters via Joule heating was also assessed. Rapid response times (∼15 s) at low bias voltage (≤5 V) and good thermal resistance characteristics (213-258 °C cm(2)/W) were found using measured thermal imaging data. Deicing of an ice-bearing glass coupon on top of the transparent heater was also successfully demonstrated.

  17. Flexible digestion strategies and trace metal assimilation in marine bivalves

    USGS Publications Warehouse

    Decho, Alan W.; Luoma, Samuel N.

    1996-01-01

    Pulse-chase experiments show that two marine bivalves take optimal advantage of different types of particulate food by varying food retention time in a flexible two-phase digestive system. For example, carbon is efficiently assimilated from bacteria by subjecting nearly all the ingested bacteria to prolonged digestion. Prolonging digestion also enhances assimilation of metals, many of which are toxic in minute quantities if they are biologically available. Detritus-feeding aquatic organisms have always lived in environments naturally rich in particle-reactive metals. We suggest that avoiding excess assimilation of metals could be a factor in the evolution of digestion strategies. We tested that suggestion by studying digestion of particles containing different Cr concentrations. We show that bivalves are capable of modifying the digestive processing of food to reduce exposure to high, biologically available, Cr concentrations. The evolution of a mechanism in some species to avoid high concentrations of metals in food could influence how effects of modern metal pollution are manifested in marine ecosystems.

  18. Flexible transition metal dichalcogenide nanosheets for band-selective photodetection

    PubMed Central

    Velusamy, Dhinesh Babu; Kim, Richard Hahnkee; Cha, Soonyoung; Huh, June; Khazaeinezhad, Reza; Kassani, Sahar Hosseinzadeh; Song, Giyoung; Cho, Suk Man; Cho, Sung Hwan; Hwang, Ihn; Lee, Jinseong; Oh, Kyunghwan; Choi, Hyunyoug; Park, Cheolmin

    2015-01-01

    The photocurrent conversions of transition metal dichalcogenide nanosheets are unprecedentedly impressive, making them great candidates for visible range photodetectors. Here we demonstrate a method for fabricating micron-thick, flexible films consisting of a variety of highly separated transition metal dichalcogenide nanosheets for excellent band-selective photodetection. Our method is based on the non-destructive modification of transition metal dichalcogenide sheets with amine-terminated polymers. The universal interaction between amine and transition metal resulted in scalable, stable and high concentration dispersions of a single to a few layers of numerous transition metal dichalcogenides. Our MoSe2 and MoS2 composites are highly photoconductive even at bending radii as low as 200 μm on illumination of near infrared and visible light, respectively. More interestingly, simple solution mixing of MoSe2 and MoS2 gives rise to blended composite films in which the photodetection properties were controllable. The MoS2/MoSe2 (5:5) film showed broad range photodetection suitable for both visible and near infrared spectra. PMID:26333531

  19. Non-pulsed electrochemical impregnation of flexible metallic battery plaques

    DOEpatents

    Maskalick, Nicholas J.

    1982-01-01

    A method of loading active battery material into porous, flexible, metallic battery plaques, comprises the following steps: precipitating nickel hydroxide active material within the plaque, by making the plaque cathodic, at a high current density, in an electro-precipitation cell also containing a consumable nickel anode and a solution comprising nickel nitrate, having a pH of between 2.0 and 2.8; electrochemically oxidizing the precipitate in caustic formation solution; and repeating the electro-precipitation step at a low current density.

  20. Flexible circular waveguides at millimeter wavelengths from metallized Teflon tubing

    NASA Astrophysics Data System (ADS)

    Obrzut, J.; Goldsmith, P. F.

    1990-03-01

    Flexible waveguides for use at millimeter wavelengths have been fabricated by deposition of metallic film onto the composite-modified inside surface of Teflon tubing. The attenuation characteristics in the range 80 to 115 GHz show losses on the order of 0.1 dB/cm. Bending, twisting, and rotating to the limit of plastic mechanical stability (curvature radius typically greater than 8 cm) have a negligible effect on the attenuation, and bend angles less than 45 deg produce relatively small changes in the insertion phase.

  1. Flexible metallic seal for transition duct in turbine system

    DOEpatents

    Flanagan, James Scott; LeBegue, Jeffrey Scott; McMahan, Kevin Weston; Dillard, Daniel Jackson; Pentecost, Ronnie Ray

    2014-04-22

    A turbine system is disclosed. In one embodiment, the turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes an interface member for interfacing with a turbine section. The turbine system further includes a flexible metallic seal contacting the interface member to provide a seal between the interface member and the turbine section.

  2. Nanowire LEDs grown directly on flexible metal foil

    SciTech Connect

    May, Brelon J.; Sarwar, A. T. M. Golam; Myers, Roberto C.

    2016-04-04

    Using molecular beam epitaxy, self-assembled AlGaN nanowires are grown directly on Ta and Ti foils. Scanning electron microscopy shows that the nanowires are locally textured with the underlying metallic grains. Photoluminescence spectra of GaN nanowires grown on metal foils are comparable to GaN nanowires grown on single crystal Si wafers. Similarly, photoluminescence lifetimes do not vary significantly between these samples. Operational AlGaN light emitting diodes are grown directly on flexible Ta foil with an electroluminescence peak emission of ∼350 nm and a turn-on voltage of ∼5 V. These results pave the way for roll-to-roll manufacturing of solid state optoelectronics.

  3. Role of hydrocarbons in pore expansion and contraction of a flexible metal-organic framework

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; Nune, Satish K.; Fernandez, Carlos A.; McGrail, B. Peter; Atwood, Jerry L.

    2011-05-06

    A flexible metal organic framework obtained from a flexible organic linker shows a breathing phenomenon upon adsorption of polar protic and non-polar solvents. Sorption profiles indicate favorable interactions with non-polar solvents over polar solvents.

  4. A review of flexible lithium-sulfur and analogous alkali metal-chalcogen rechargeable batteries.

    PubMed

    Peng, Hong-Jie; Huang, Jia-Qi; Zhang, Qiang

    2017-08-29

    Flexible energy storage systems are imperative for emerging flexible devices that are revolutionizing our life. Lithium-ion batteries, the current main power sources, are gradually approaching their theoretical limitation in terms of energy density. Therefore, alternative battery chemistries are urgently required for next-generation flexible power sources with high energy densities, low cost, and inherent safety. Flexible lithium-sulfur (Li-S) batteries and analogous flexible alkali metal-chalcogen batteries are of paramount interest owing to their high energy densities endowed by multielectron chemistry. In this review, we summarized the recent progress of flexible Li-S and analogous batteries. A brief introduction to flexible energy storage systems and general Li-S batteries has been provided first. Progress in flexible materials for flexible Li-S batteries are reviewed subsequently, with a detailed classification of flexible sulfur cathodes as those based on carbonaceous (e.g., carbon nanotubes, graphene, and carbonized polymers) and composite (polymers and inorganics) materials and an overview of flexible lithium anodes and flexible solid-state electrolytes. Advancements in other flexible alkali metal-chalcogen batteries are then introduced. In the next part, we emphasize the importance of cell packaging and flexibility evaluation, and two special flexible battery prototypes of foldable and cable-type Li-S batteries are highlighted. In the end, existing challenges and future development of flexible Li-S and analogous alkali metal-chalcogen batteries are summarized and prospected.

  5. Thin-film silicon for flexible metal-air batteries.

    PubMed

    Garamoun, Ahmed; Schubert, Markus B; Werner, Jürgen H

    2014-12-01

    Due to its high energy density, theoretical studies propose silicon as a promising candidate material for metal-air batteries. Herein, for the first time, experimental results detail the use of n-type doped amorphous silicon and silicon carbide as fuel in Si-air batteries. Thin-film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si-air batteries exhibit a specific capacity of 269 Ah kg(-1) and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm(-2) , corresponding to a specific energy of 229 Wh kg(-1) . Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si-air cells continues as long as there is silicon available for oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Flexibility.

    ERIC Educational Resources Information Center

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  7. Flexibility.

    ERIC Educational Resources Information Center

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  8. Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

    PubMed Central

    Donatelli, Gianfranco; Cereatti, Fabrizio; Dumont, Jean-Loup; Dhumane, Parag; Tuszynski, Thierry; Vergeau, Bertrand Marie; Meduri, Bruno

    2016-01-01

    Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist. PMID:27489716

  9. Nanotribological investigations of NCD coatings covering metal slitting saws

    NASA Astrophysics Data System (ADS)

    Golabczak, A.; Niedzielski, Piotr; Mitura, Stanislaw; Zak, J.

    1997-06-01

    In the paper an assessment of the usefulness of a method for the formation of a hard carbon coating on the working surface of metal slitting saws has been presented. Metal slitting saws were used to cut off the tips of non-ferrous metals in printed-circuit boards. The results o the authors' own investigations concerning the assessment of life of metal slitting saws with modified geometry of the cutting edge and a hard carbon coating have been presented. Conclusions on the practicability of the RF PCVD method used have been formulated.

  10. Metal{Polymer Hybrid Materials For Flexible Transparent Conductors

    NASA Astrophysics Data System (ADS)

    Narayanan, Sudarshan

    The field of organic electronics, till recently a mere research topic, is currently making rapid strides and tremendous progress into entering the mainstream electronics industry with several applications and products such as OLED televisions, curved displays, wearable devices, flexible solar cells, etc. already having been commercialized. A major component in these devices, especially for photovoltaic applications, is a transparent conductor used as one of the electrodes, which in most commercial applications are highly doped wide bandgap semiconducting oxides also called Transparent Conducting Oxides (TCOs). However, TCOs exhibit inherent disadvantages such as limited supply, brittle mechanical properties, expensive processing that present major barriers for the more widespread economic use in applications such as exible transparent conductors, owing to which suitable alternative materials are being sought. In this context we present two approaches in realizing alternative TCs using metal-polymer hybrid materials, with high figures of merit that are easily processable, reasonably inexpensive and mechanically robust as well. In this context, our first approach employs laminated metal-polymer photonic bandgap structures to effectively tune optical and electrical properties by an appropriate design of the material stack, factoring in the effect of the materials involved, the number of layers and layer properties. We have found that in the case of a four-bilayer Au/polystyrene (AujPS) laminate structure, an enhancement in optical transmittance of ˜ 500% in comparison to a monolithic A film of equivalent thickness, can be achieved. The high conductivity (˜ 106 O--1cm--1) of the metallic component, Au in this case, also ensures planar conductivity; metallic inclusions in the dielectric polymer layer can in principle give rise to out-of-plane conductivity as well enabling a fully functional TC. Such materials also have immense potential for several other applications

  11. Microfluidic Patterning of Metal Structures for Flexible Conductors by In Situ Polymer-Assisted Electroless Deposition.

    PubMed

    Liang, Suqing; Li, Yaoyao; Zhou, Tingjiao; Yang, Jinbin; Zhou, Xiaohu; Zhu, Taipeng; Huang, Junqiao; Zhu, Julie; Zhu, Deyong; Liu, Yizhen; He, Chuanxin; Zhang, Junmin; Zhou, Xuechang

    2017-02-01

    A low-cost, solution-processed, versatile, microfluidic approach is developed for patterning structures of highly conductive metals (e.g., copper, silver, and nickel) on chemically modified flexible polyethylene terephthalate thin films by in situ polymer-assisted electroless metal deposition. This method has significantly lowered the consumption of catalyst as well as the metal plating solution.

  12. The effect of paclitaxel-eluting covered metal stents versus covered metal stents in a rabbit esophageal squamous carcinoma model

    PubMed Central

    Zhang, Yin; Ma, Limei; Huang, Jin; Shuang, Jinquan

    2017-01-01

    Background The use of self-expanding metallic stents (SEMSs) is the current treatment of choice for malignant gastrointestinal obstructions. However, these stents can promote only drainage and have no antitumor effect. Some studies have reported that drug-eluting SEMSs may have tumor inhibition potential. The aim of this study was to evaluate the efficiency and safety of paclitaxel-eluting SEMSs (PEMSs) in rabbit esophageal cancer models. Materials and methods A PEMS was covered with a paclitaxel-incorporated membrane, in which the concentration of paclitaxel was 10% (wt/vol). The rabbit models were created endoscopically. Then, a PEMS or SEMS was endoscopically inserted into the rabbit esophagus. Two weeks after stent placement, the rabbits were sacrificed, and we evaluated the tumor volume, area of the wall defect, area of the tumor under endoscopic ultrasound (EUS) before and after stent placement, status of the proximal esophageal obstruction, tumor metastasis food-intake and weight loss. Results A total of 26 rabbits received stent insertion and survived until sacrifice, and migration occurred in 4 cases, 3 in SEMS group and 1 in PEMS group. For the remaining 22 rabbits, at the sacrificed time, the average tumor volume was 7.00±4.30 cm3 in the SEMS group and 0.94±1.51 cm3 in the PEMS group (P<0.05). The area of the esophageal wall defect was 0.70±0.63 cm2 in the SEMS group and 0.17±0.16 cm2 in the PEMS group (P<0.05). The tumor area under EUS was 4.40±1.47 cm2 in the SEMS group and 1.30±1.06 cm2 in the PEMS group (P<0.05). At the time of stent placement, tumor area under EUS was comparable in the two groups. Other indices did not significantly differ between the two groups. Conclusions SEMS and PEMS are both safe and effective to relieve dysphagia in rabbit esophageal cancer models. A PEMS can serve as an alternative tool for advanced esophageal cancer that may inhibit tumor growth by serving as a drug sustained-release platform. Clinical trials of the

  13. Flexible Fiber-Shaped Supercapacitor Based on Nickel-Cobalt Double Hydroxide and Pen Ink Electrodes on Metallized Carbon Fiber.

    PubMed

    Gao, Libo; Surjadi, James Utama; Cao, Ke; Zhang, Hongti; Li, Peifeng; Xu, Shang; Jiang, Chenchen; Song, Jian; Sun, Dong; Lu, Yang

    2017-02-15

    Flexible fiber-shaped supercapacitors (FSSCs) are recently of extensive interest for portable and wearable electronic gadgets. Yet the lack of industrial-scale flexible fibers with high conductivity and capacitance and low cost greatly limits its practical engineering applications. To this end, we here present pristine twisted carbon fibers (CFs) coated with a thin metallic layer via electroless deposition route, which exhibits exceptional conductivity with ∼300% enhancement and superior mechanical strength (∼1.8 GPa). Subsequently, the commercially available conductive pen ink modified high conductive composite fibers, on which uniformly covered ultrathin nickel-cobalt double hydroxides (Ni-Co DHs) were introduced to fabricate flexible FSSCs. The synthesized functionalized hierarchical flexible fibers exhibit high specific capacitance up to 1.39 F·cm(-2) in KOH aqueous electrolyte. The asymmetric solid-state FSSCs show maximum specific capacitance of 28.67 mF·cm(-2) and energy density of 9.57 μWh·cm(-2) at corresponding power density as high as 492.17 μW·cm(-2) in PVA/KOH gel electrolyte, with demonstrated high flexibility during stretching, demonstrating their potential in flexible electronic devices and wearable energy systems.

  14. MEED studies of thin metal film covered semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Shimaoka, G.

    1991-06-01

    Results of observations of thin metal films deposited on clean surfaces of semiconductors, such as Si, GaAs and GaP, in the early stage of deposition in UHV, are reported with particular emphasis on in-situ MEED observations at 1-5 kV using a grazing angle of incidence. Various atomic rearrangements and reconstructions due to thin metal deposits were observed, for example: 2 × 1 and 4 × 5 reconstruction of Ni on a clean Si(110)16 × 2 surface, and formation of a one-dimensional lattice of Ag on a coplanar plane of GaAs (001) and GaP (001) and (011). These results are also discussed in terms of surface structures with special emphasis on the early stages of metal deposition and on the metal/semiconductor interface.

  15. Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors.

    PubMed

    Yu, You; Yan, Casey; Zheng, Zijian

    2014-08-20

    Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided.

  16. Thin-film composite materials as a dielectric layer for flexible metal-insulator-metal capacitors.

    PubMed

    Tiwari, Jitendra N; Meena, Jagan Singh; Wu, Chung-Shu; Tiwari, Rajanish N; Chu, Min-Ching; Chang, Feng-Chih; Ko, Fu-Hsiang

    2010-09-24

    A new organic-organic nanoscale composite thin-film (NCTF) dielectric has been synthesized by solution deposition of 1-bromoadamantane and triblock copolymer (Pluronic P123, BASF, EO20-PO70-EO20), in which the precursor solution has been achieved with organic additives. We have used a sol-gel process to make a metal-insulator-metal capacitor (MIM) comprising a nanoscale (10 nm-thick) thin-film on a flexible polyimide (PI) substrate at room temperature. Scanning electron microscope and atomic force microscope revealed that the deposited NCTFs were crack-free, uniform, highly resistant to moisture absorption, and well adhered on the Au-Cr/PI. The electrical properties of 1-bromoadamantane-P123 NCTF were characterized by dielectric constant, capacitance, and leakage current measurements. The 1-bromoadamantane-P123 NCTF on the PI substrate showed a low leakage current density of 5.5 x 10(-11) A cm(-2) and good capacitance of 2.4 fF at 1 MHz. In addition, the calculated dielectric constant of 1-bromoadamantane-P123 NCTF was 1.9, making them suitable candidates for use in future flexible electronic devices as a stable intermetal dielectric. The electrical insulating properties of 1-bromoadamantane-P123 NCTF have been improved due to the optimized dipole moments of the van der Waals interactions.

  17. Separation of polar compounds using a flexible metal-organic framework

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; Annapureddy, Harsha V.; Dang, Liem X.; Krishna, Rajamani; Nune, Satish K.; Fernandez, Carlos A.; Liu, Jian; McGrail, B. Peter

    2015-01-01

    A flexible metal-organic framework constructed from a flexible linker is shown to possess the capability of separating mixtures of polar compounds by exploiting the differences in the saturation capacities of the constituents. The separation possibilities with the flexible MOF include mixtures of propanol isomers, and various azeotropes. Transient breakthrough simulations show that these sorption-based separations are in favor of the component with higher saturation capacity.

  18. Thin-Film Solar Cell Fabricated on a Flexible Metallic Substrate

    DOEpatents

    Tuttle, J. R.; Noufi, R.; Hasoon, F. S.

    2006-05-30

    A thin-film solar cell (10) is provided. The thin-film solar cell (10) comprises a flexible metallic substrate (12) having a first surface and a second surface. A back metal contact layer (16) is deposited on the first surface of the flexible metallic substrate (12). A semiconductor absorber layer (14) is deposited on the back metal contact. A photoactive film deposited on the semiconductor absorber layer (14) forms a heterojunction structure and a grid contact (24) deposited on the heterjunction structure. The flexible metal substrate (12) can be constructed of either aluminium or stainless steel. Furthermore, a method of constructing a solar cell is provided. The method comprises providing an aluminum substrate (12), depositing a semiconductor absorber layer (14) on the aluminum substrate (12), and insulating the aluminum substrate (12) from the semiconductor absorber layer (14) to inhibit reaction between the aluminum substrate (12) and the semiconductor absorber layer (14).

  19. Method of manufacturing flexible metallic photonic band gap structures, and structures resulting therefrom

    DOEpatents

    Gupta, Sandhya; Tuttle, Gary L.; Sigalas, Mihail; McCalmont, Jonathan S.; Ho, Kai-Ming

    2001-08-14

    A method of manufacturing a flexible metallic photonic band gap structure operable in the infrared region, comprises the steps of spinning on a first layer of dielectric on a GaAs substrate, imidizing this first layer of dielectric, forming a first metal pattern on this first layer of dielectric, spinning on and imidizing a second layer of dielectric, and then removing the GaAs substrate. This method results in a flexible metallic photonic band gap structure operable with various filter characteristics in the infrared region. This method may be used to construct multi-layer flexible metallic photonic band gap structures. Metal grid defects and dielectric separation layer thicknesses are adjusted to control filter parameters.

  20. Thin-film solar cell fabricated on a flexible metallic substrate

    DOEpatents

    Tuttle, John R.; Noufi, Rommel; Hasoon, Falah S.

    2006-05-30

    A thin-film solar cell (10) is provided. The thin-film solar cell (10) comprises a flexible metallic substrate (12) having a first surface and a second surface. A back metal contact layer (16) is deposited on the first surface of the flexible metallic substrate (12). A semiconductor absorber layer (14) is deposited on the back metal contact. A photoactive film deposited on the semiconductor absorber layer (14) forms a heterojunction structure and a grid contact (24) deposited on the heterjunction structure. The flexible metal substrate (12) can be constructed of either aluminium or stainless steel. Furthermore, a method of constructing a solar cell is provided. The method comprises providing an aluminum substrate (12), depositing a semiconductor absorber layer (14) on the aluminum substrate (12), and insulating the aluminum substrate (12) from the semiconductor absorber layer (14) to inhibit reaction between the aluminum substrate (12) and the semiconductor absorber layer (14).

  1. Highly Conductive Transparent and Flexible Electrodes Including Double-Stacked Thin Metal Films for Transparent Flexible Electronics.

    PubMed

    Han, Jun Hee; Kim, Do-Hong; Jeong, Eun Gyo; Lee, Tae-Woo; Lee, Myung Keun; Park, Jeong Woo; Lee, Hoseung; Choi, Kyung Cheol

    2017-05-17

    To keep pace with the era of transparent and deformable electronics, electrode functions should be improved. In this paper, an innovative structure is suggested to overcome the trade-off between optical and electrical properties that commonly arises with transparent electrodes. The structure of double-stacked metal films showed high conductivity (<3 Ω/sq) and high transparency (∼90%) simultaneously. A proper space between two metal films led to high transmittance by an optical phenomenon. The principle of parallel connection allowed the electrode to have high conductivity. In situ fabrication was possible because the only materials composing the electrode were silver and WO3, which can be deposited by thermal evaporation. The electrode was flexible enough to withstand 10 000 bending cycles with a 1 mm bending radius. Furthermore, a few μm scale patterning of the electrode was easily implemented by using photolithography, which is widely employed industrially for patterning. Flexible organic light-emitting diodes and a transparent flexible thin-film transistor were successfully fabricated with the proposed electrode. Various practical applications of this electrode to new transparent flexible electronics are expected.

  2. Metal mobilization under alkaline conditions in ash-covered tailings.

    PubMed

    Lu, Jinmei; Alakangas, Lena; Wanhainen, Christina

    2014-06-15

    The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Magnetic behavior of nanostructured glass covered metallic wires

    NASA Astrophysics Data System (ADS)

    Chiriac, H.; Óvári, T. A.; Pop, Gh.; Barariu, Firuta

    1997-04-01

    We present a study of the evolution of the magnetic properties and behavior of Fe73.5Cu1Nb3Si13.5B9 glass covered wires and wires after glass removal with the annealing temperature up to 600 °C starting from the amorphous state. The changes induced in the magnetic properties of these wires are determined by the stress relief process occurring at temperatures below 550 °C, and by the appearance of the nanosized α-FeSi crystalline grains after annealing for 1 h at 550 °C. The nanocrystalline phase formation leads to an improvement of the soft magnetic properties of these wires—increase of permeability and decrease of the coercive force—but also determines the disappearance of the large Barkhausen effect presented by these wires in the amorphous state. Annealing at temperatures over 550 °C determines a depreciation of the soft magnetic properties of both glass covered wires and wires after glass removal. The magnetic behavior of such wires can be fully explained by taking into account the relaxation of the internal stresses with increasing the annealing temperature as well as the changes in the magnetostriction constant due to the appearance of the nanocrystalline grains.

  4. A Flexible Stent with Small Intestinal Submucosa Covering for Direct Intrahepatic Portocaval Shunt: Experimental Pilot Study in Swine

    SciTech Connect

    Niyyati, Mahtab; Petersen, Bryan D.; Pavcnik, Dusan Uchida, Barry T.; Timmermans, Hans A.; Hiraki, Takao; Wu Renghong; Brountzos, Elias; Keller, Frederick S.; Roesch, Josef

    2005-04-15

    The suitability of the flexible sandwich Zilver stent-graft (SZSG) with a biologically active tissue layer (small intestinal submucosa) for creation of the intravascular ultrasound (IVUS)-guided direct intrahepatic portocaval shunt (DIPS) was explored in six young swine in a search for a flexible system to replace the rigid polytetrafluoroethylene (PTFE) stent originally used by this group with limited success. The portal vein was punctured from the inferior vena cava through the caudate lobe of the liver using IVUS guidance. After balloon dilation of the puncture tract, DIPS was successfully created in all animals with use of an SZSG 9 mm in diameter and 6 cm or 8 cm long. Only one DIPS remained well patent at 14 days when the animal had to be killed because of encephalopathy. DIPS in the other five animals were found to be either severely stenosed (3 animals) or occluded (2 animals) at 4 weeks due to accelerated formation of neointimal hyperplasia (NIH) in the liver parenchymal portion of the shunt and superimposed thrombosis. The lack of high pressure in the portal system contributed to early endograft closure. The flexible stent and the covering fail badly. The reason for this could be due to either component. More work is required to find a reliable flexible system with long-term patency. Exploration of the IVUS-guided direct extrahepatic portocaval shunt is suggested.

  5. Interaction of Electromagnetic Waves with Two-Dimensional Metal Covered with Radar Absorbing Material and Plasma

    NASA Astrophysics Data System (ADS)

    Lan, Chaohui; Hu, Xiwei; Jiang, Zhonghe

    2008-12-01

    A two-dimensional metal model is established to investigate the stealth mechanisms of radar absorbing material (RAM) and plasma when they cover the model together. Using the finite-difference time-domain (FDTD) method, the interaction of electromagnetic (EM) waves with the model can be studied. In this paper, three covering cases are considered: a. RAM or plasma covering the metal solely; b. RAM and plasma covering the metal, while plasma is placed outside; c. RAM and plasma covering the metal, while RAM is placed outside. The calculated results show that the covering order has a great influence on the absorption of EM waves. Compared to case a, case b has an advantage in the absorption of relatively high-frequency EM waves (HFWs), whereas case c has an advantage in the absorption of relatively low-frequency EM waves (LFWs). Through the optimization of the parameters of both plasma and RAM, it is hopeful to obtain a broad absorption band by RAM and plasma covering. Near-field attenuation rate and far-field radar cross section (RCS) are employed to compare the different cases.

  6. Review on Metallic and Plastic Flexible Dye Sensitized Solar Cell

    NASA Astrophysics Data System (ADS)

    Yugis, A. R.; Mansa, R. F.; Sipaut, C. S.

    2015-04-01

    Dye sensitized solar cells (DSSCs) are a promising alternative for the development of a new generation of photovoltaic devices. DSSCs have promoted intense research due to their low cost and eco-friendly advantage over conventional silicon-based crystalline solar cells. In recent years, lightweight flexible types of DSSCs have attracted much intention because of drastic reduction in production cost and more extensive application. The substrate that used as electrode of the DSSCs has a dominant impact on the methods and materials that can be applied to the cell and consequently on the resulting performance of DSSCs. Furthermore, the substrates influence significantly the stability of the device. Although the power conversion efficiency still low compared to traditional glass based DSSCs, flexible DSSCs still have potential to be the most efficient and easily implemented technology.

  7. Transition-Metal-Free Biomolecule-Based Flexible Asymmetric Supercapacitors.

    PubMed

    Yang, Yun; Wang, Hua; Hao, Rui; Guo, Lin

    2016-09-01

    A transition-metal-free asymmetric supercapacitor (ASC) is successfully fabricated based on an earth-abundant biomass derived redox-active biomolecule, named lawsone. Such an ASC exhibits comparable or even higher energy densities than most of the recently reported transition-metal-based ASCs, and this green ASC generation from renewable resources is promising for addressing current issues of electronic hazard processing, high cost, and unsustainability.

  8. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors

    PubMed Central

    Muralee Gopi, Chandu V. V.; Ravi, Seenu; Rao, S. Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-01-01

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg−1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices. PMID:28422182

  9. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors

    NASA Astrophysics Data System (ADS)

    Muralee Gopi, Chandu V. V.; Ravi, Seenu; Rao, S. Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-04-01

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg-1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

  10. Studies of gas adsorption in flexible Metal-Organic frameworks

    NASA Astrophysics Data System (ADS)

    Sircar, Sarmishtha

    Flexible Metal-Organic frameworks that exhibit a gate-opening (GO) adsorption mechanism have potential for gas separations and gas storage. The GO phenomenon occurs when molecular gates in the structure expand/contract in response to the activation/de-activation of a system variable e.g. temperature, pressure or gas. Sharp discontinuities in the isotherm leading to S-shapes and large adsorption-desorption hysteresis are typical of this phenomenon. This study investigates the kinetics and thermodynamics of the GO behavior by combining adsorption measurements and analytical modeling of adsorption kinetics and capacity as a function of adsorbate, GO pressure, and temperature. Basic understanding of GO mechanism will help harness GO-MOF's as adsorbents for gas separations and storage. Experiments were performed on two precharacterized MOFs with verified GO behavior. These are (1) Zn2(bpdc)2(bpee), which expands from a relative amorphous to crystalline structure and (2) Cu[(dhbc) 2(4,4f-bpy)]H2O, a mutually interdigitated 2-D structure (bpdc = biphenyldicarboxylate, bpee = 1,2]bipyridylethene; DMF = N,N-dimethyl formamide, dhbc= 2,5-dihydroxybenzoic acid, bpy=bipyridine). Both sub- and super-critical adsorption data were collected using three adsorption units: a standard low-pressure volumetric adsorption unit, a commercial high-pressure gravimetric analyzer and a custom-built high-pressure differential volumetric unit. Collected laboratory data were combined with published adsorption rate and isotherm data for analysis to broaden the range of data collection. The accuracy of the high-pressure differential unit was improved by over 300-fold by changing analytical methods of processing data to establish a reliable null correction. A pronounced effect of the allowed experimental time was found at cryogenic temperatures on (1). Tightening the stability criteria used by the adsorption equipment to determine equilibration increased the experimental time from the order of

  11. Flexible perovskite solar cells based on the metal-insulator-semiconductor structure.

    PubMed

    Wei, Jing; Li, Heng; Zhao, Yicheng; Zhou, Wenke; Fu, Rui; Pan, Huiyue; Zhao, Qing

    2016-09-14

    The metal-insulator-semiconductor (MIS) structure is applied to perovskite solar cells, in which the traditional compact layer TiO2 is replaced by Al2O3 as the hole blocking material to realize an all-low-temperature process. Flexible devices based on this structure are also realized with excellent flexibility, which hold 85% of their initial efficiency after bending 100 times.

  12. Direct synthesis of highly textured Ge on flexible polyimide films by metal-induced crystallization

    SciTech Connect

    Oya, N.; Toko, K. Suemasu, T.; Saitoh, N.; Yoshizawa, N.

    2014-06-30

    The highly (111)-textured Ge thin film (50-nm thickness) is demonstrated on a flexible polyimide film via the low-temperature crystallization (325 °C) of amorphous Ge using Al as a catalyst. Covering the polyimide with insulators significantly improved the crystal quality of the resulting Ge layer. In particular, SiN covering led to 97% (111)-oriented Ge with grains 200 μm in size, two orders larger than the grain size of polycrystalline Ge directly formed on the polyimide film. This achievement will give a way to realize advanced electronic and optical devices simultaneously allowing for high performance, inexpensiveness, and flexibility.

  13. Esophageal and Bronchial Perforations After Thoracic Aortic Aneurysm Replacement: Successful Repair with Covered Metallic Stents

    SciTech Connect

    Sueyoshi, Eijun; Imada, Tatsuya; Sakamoto, Ichiro; Uetani, Masataka; Hayashi, Kuniaki

    2003-09-15

    Esophageal and bronchial perforations are rare but potentially fatal complications of descending thoracic aortic aneurysm replacement. This report presents a 67-year-old man with both esophageal and bronchial perforations that occurred after descending thoracic aortic aneurysm replacement. Surgical repair was performed, but the lesions perforated again. Two covered metallic stent prostheses introduced into both the esophagus and left main bronchus led to the improvement of mediastinitis by sealing the perforations. To our knowledge, this is the first report describing successful treatment for esophageal and bronchial perforations using covered metallic stents. Placement of covered metallic stents can be an option for the treatment of patients with esophagorespiratory tract perforations, especially those who are in critical condition.

  14. Transparent conducting materials: Flexibility with a metallic skin

    NASA Astrophysics Data System (ADS)

    Hosono, Hideo

    2012-04-01

    Transparent, metallic conducting thin films are key for applications such as flatpanel displays and solar cells, and heavily electron-doped ionic oxide materials have been intensively studied for this purpose. A class of conductors that are transparent in the near-infrared region has now been developed using a topological insulator.

  15. 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

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

    SciTech Connect

    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 100 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.

  17. Lightweight electrically-powered flexible thermal laminate. [made of metal and nonconductive yarns

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Sauers, D. G. (Inventor)

    1978-01-01

    Cross-layered woven or unwoven yarns are used to provide an active thermal control mechanism for spacecraft use. One set of yarns is composed of flexible electrically conductive metal fibers which are capable of being resistance heated by the application of voltage. Another set of yarns, nonconductive and flexible, provides mechanical strength and precludes the passage of electrical current between the metal yarns by virtue of the spacing between them. A lightweight, electrically nonconductive film is bonded to the cross-layered yarns to protect the metal yarns from the elements (minimize electrical shorts from moisture such as rain), to provide additional strength to the fabric, and to prevent conductive loss of heat in nonvacuum applications. The nonconductive film is metalized on its obverse side to provide a more uniform heat load distribution.

  18. Flexible supercapacitor electrodes based on real metal-like cellulose papers.

    PubMed

    Ko, Yongmin; Kwon, Minseong; Bae, Wan Ki; Lee, Byeongyong; Lee, Seung Woo; Cho, Jinhan

    2017-09-14

    The effective implantation of conductive and charge storage materials into flexible frames has been strongly demanded for the development of flexible supercapacitors. Here, we introduce metallic cellulose paper-based supercapacitor electrodes with excellent energy storage performance by minimizing the contact resistance between neighboring metal and/or metal oxide nanoparticles using an assembly approach, called ligand-mediated layer-by-layer assembly. This approach can convert the insulating paper to the highly porous metallic paper with large surface areas that can function as current collectors and nanoparticle reservoirs for supercapacitor electrodes. Moreover, we demonstrate that the alternating structure design of the metal and pseudocapacitive nanoparticles on the metallic papers can remarkably increase the areal capacitance and rate capability with a notable decrease in the internal resistance. The maximum power and energy density of the metallic paper-based supercapacitors are estimated to be 15.1 mW cm(-2) and 267.3 μWh cm(-2), respectively, substantially outperforming the performance of conventional paper or textile-type supercapacitors.With ligand-mediated layer-by-layer assembly between metal nanoparticles and small organic molecules, the authors prepare metallic paper electrodes for supercapacitors with high power and energy densities. This approach could be extended to various electrodes for portable/wearable electronics.

  19. Ultrafast laser ablation of metal films on flexible substrates

    NASA Astrophysics Data System (ADS)

    Gallais, L.; Bergeret, E.; Wang, B.; Guerin, M.; Bènevent, E.

    2014-04-01

    For the development of organic electronics on flexible substrates, we study the potentialities of direct laser patterning of conductive films deposited on plastic foils. The materials under study are silver and platinum films (100-nm thick) deposited on Kapton® substrates. The experiments are done using a laser source operating at 1030 nm, 500 fs, under different irradiation conditions: single and multiple pulses at various frequencies. The laser ablation thresholds are measured and the ablation morphologies are analyzed with scanning electron microscopy. The results of these investigations show that photomechanical effects lead to delamination of the film and that depending of the irradiation conditions, incubation or heat accumulation effects can occur. The experimental results are compared to simulations based on the two-temperature model. Particularly we study the heat accumulation effects that can occur in the case of multiple pulses and that are detrimental for plastic substrates.

  20. Flexible Polymer/Metal/Polymer and Polymer/Metal/Inorganic Trilayer Transparent Conducting Thin Film Heaters with Highly Hydrophobic Surface.

    PubMed

    Kang, Tae-Woon; Kim, Sung Hyun; Kim, Cheol Hwan; Lee, Sang-Mok; Kim, Han-Ki; Park, Jae Seong; Lee, Jae Heung; Yang, Yong Suk; Lee, Sang-Jin

    2017-09-27

    Polymer/metal/polymer and polymer/metal/inorganic trilayer-structured transparent electrodes with fluorocarbon plasma polymer thin film heaters have been proposed. The polymer/metal/polymer and polymer/metal/inorganic transparent conducting thin films fabricated on a large-area flexible polymer substrate using a continuous roll-to-roll sputtering process show excellent electrical properties and visible-light transmittance. They also exhibit water-repelling surfaces to prevent wetting and to remove contamination. In addition, the adoption of a fluorocarbon/metal/fluorocarbon film permits an outer bending radius as small as 3 mm. These films have a sheet resistance of less than 5 Ω sq(-1), sufficient to drive light-emitting diode circuits. The thin film heater with the fluorocarbon/Ag/SiNx structure exhibits excellent heating characteristics, with a temperature reaching 180 °C under the driving voltage of 13 V. Therefore, the proposed polymer/metal/polymer and polymer/metal/inorganic transparent conducting electrodes using polymer thin films can be applied in flexible and rollable displays as well as automobile window heaters and other devices.

  1. Flexible and Robust Thermoelectric Generators Based on All-Carbon Nanotube Yarn without Metal Electrodes.

    PubMed

    Choi, Jaeyoo; Jung, Yeonsu; Yang, Seung Jae; Oh, Jun Young; Oh, Jinwoo; Jo, Kiyoung; Son, Jeong Gon; Moon, Seung Eon; Park, Chong Rae; Kim, Heesuk

    2017-08-22

    As practical interest in flexible/or wearable power-conversion devices increases, the demand for high-performance alternatives to thermoelectric (TE) generators based on brittle inorganic materials is growing. Herein, we propose a flexible and ultralight TE generator (TEG) based on carbon nanotube yarn (CNTY) with excellent TE performance. The as-prepared CNTY shows a superior electrical conductivity of 3147 S/cm due to increased longitudinal carrier mobility derived from a highly aligned structure. Our TEG is innovative in that the CNTY acts as multifunctions in the same device. The CNTY is alternatively doped into n- and p-types using polyethylenimine and FeCl3, respectively. The highly conductive CNTY between the doped regions is used as electrodes to minimize the circuit resistance, thereby forming an all-carbon TEG without additional metal deposition. A flexible TEG based on 60 pairs of n- and p-doped CNTY shows the maximum power density of 10.85 and 697 μW/g at temperature differences of 5 and 40 K, respectively, which are the highest values among reported TEGs based on flexible materials. We believe that the strategy proposed here to improve the power density of flexible TEG by introducing highly aligned CNTY and designing a device without metal electrodes shows great potential for the flexible/or wearable power-conversion devices.

  2. Development of high-flexible triboelectric generators using plastic metal as electrodes

    NASA Astrophysics Data System (ADS)

    Yang, Sen-Yeu; Shih, Jian-Fu; Chang, Chih-Chieh; Yang, Chii-Rong

    2017-02-01

    A triboelectric generator is a device that harvests energy through the conversion of mechanical energy into electrical energy. In this work, two polymer materials (PDMS and PET) were selected as triboelectric layers in conjunction with plastic metal (PM) films as conductive layers to produce an electrode with high flexibility. The PDMS film was fabricated with a microstructural array to enhance friction. The proposed PM material was prepared by mixing gallium-indium liquid metal and a glaze powder with excellent coating ability, extensibility, and conductivity. Results demonstrate the superior characteristics of the PM flexible electrodes, including large bending angle (≥180°), small curvature radius (≤1 mm), and stable conductivity. This PM-based triboelectric generator can achieve average output voltage of 80 V and current of 37.2 μA. The proposed flexible electrode with a PM conductive layer could be expected to make a notable contribution to the development of wearable devices.

  3. Flexible polymer solar cells based on Ag metallic grids and functional reduced graphene oxide composite electrode

    NASA Astrophysics Data System (ADS)

    Zheng, Qiao; Cheng, Shuying; Jia, Hongjie; Zhang, Hong; Liu, Si; Lai, Yunfeng; Yu, Jinling; Zhou, Haifang

    2017-10-01

    By combining the appropriate Ag metallic grids with a thin functional reduced graphene oxide (MGs/F-rGO) film, a suitable photoelectric flexible electrode of the polymer solar cells (PSCs) is obtained. The conductivity and transmission of the MGs/F-rGO composited films can be improved by HNO3 modified. The optimized sheet resistance and transmission of the flexible electrode achieve to 25 Ω □‑1 and 83% at 550 nm wavelength. Flexible PSCs with the MGs/F-rGO electrode show 5.63% power conversion efficiency. The photoelectric properties of the MGs/F-rGO film comparable with that of ITO substrates guarantee a high short current and an enhanced PCE of the solar cells. This method provides a feasible way for fabricating low-cost and flexible PSCs.

  4. Exploration of Gate-Opening and Breathing Phenomena in a Tailored Flexible Metal-Organic Framework.

    PubMed

    Hyun, Sung-min; Lee, Jae Hwa; Jung, Gwan Yeong; Kim, Yun Kyeong; Kim, Tae Kyung; Jeoung, Sungeun; Kwak, Sang Kyu; Moon, Dohyun; Moon, Hoi Ri

    2016-02-15

    Flexible metal-organic frameworks (MOFs) show the structural transition phenomena, gate opening and breathing, upon the input of external stimuli. These phenomena have significant implications in their adsorptive applications. In this work, we demonstrate the direct capture of these gate-opening and breathing phenomena, triggered by CO2 molecules, in a well-designed flexible MOF composed of rotational sites and molecular gates. Combining X-ray single crystallographic data of a flexible MOF during gate opening/closing and breathing with in situ X-ray powder diffraction results uncovered the origin of this flexibility. Furthermore, computational studies revealed the specific sites required to open these gates by interaction with CO2 molecules.

  5. Nonreciprocal dispersion of spin waves in ferromagnetic thin films covered with a finite-conductivity metal

    NASA Astrophysics Data System (ADS)

    Mruczkiewicz, M.; Krawczyk, M.

    2014-03-01

    We study the effect of one-side metallization of a uniform ferromagnetic thin film on its spin-wave dispersion relation in the Damon-Eshbach geometry. Due to the finite conductivity of the metallic cover layer on the ferromagnetic film, the spin-wave dispersion relation may be nonreciprocal only in a limited wave-vector range. We provide an approximate analytical solution for the spin-wave frequency, discuss its validity, and compare it with numerical results. The dispersion is analyzed systematically by varying the parameters of the ferromagnetic film, the metal cover layer and the value of the external magnetic field. The conclusions drawn from this analysis allow us to define a structure based on a 30 nm thick CoFeB film with an experimentally accessible nonreciprocal dispersion relation in a relatively wide wave-vector range.

  6. Ion-induced electron emission from cold metal targets covered by rare gases

    NASA Astrophysics Data System (ADS)

    Soszka, W.

    1990-03-01

    The energy and angular distributions of secondary electrons emitted upon ion bombardment of cold metal targets covered by rare gases in different states (two-dimensional gas layer, stationary adsorbed layer or solid film) are examined. The state of noble gas on the metal surface influences the yield of electrons from the metal (bulk electron emission) and from the adsorbed layer. A change of density of surface electrons which become localized near the positions of adsorbed particles is supposed to be responsible for the observed differences in electron emission from the targets covered by physi- or chemisorbed noble-gas layers. This is confirmed by analysis of the reflected ions which has been carried out additionally to the electron measurements.

  7. Silver metal colloidal film on a flexible polymer substrate

    NASA Astrophysics Data System (ADS)

    del Rocío Balaguera Gelves, Marcia; El Burai-Félix, Alia; De La Cruz-Montoya, Edwin; Jeréz Rozo, Jaqueline I.; Hernández-Rivera, Samuel P.

    2006-05-01

    A method to prepare metallic nanoparticles films in the presence of a hydrophilic copolymer with the aim of inhibiting the formation of clusters in the nanoparticles has been developed. Thin films prepared could be used in applications such as sensors development and substrates for surface-enhanced Raman spectroscopy. The synthesis of colloidal solutions of silver nanoparticles was achieved by the reduction AgNO 3 using sodium citrate with thermal treatment which results in a robust fabrication of gold and silver films. The polymeric films were prepared by polymerization 2-hydroxyethyl methacrylate with methacrylic acid (method 1). The other procedure employed (method 2) incorporated the use of polyvinyl pyrrolidone and polyethylene glycol as copolymers. A scanning electron microscope was used to provide microstructural information of coverage achieved. The ability to tune the nanocoating structure and spectral and electronic properties can be used for applications such as sensors used in the detection of explosives. Silver nanoparticles were also characterized by surface-enhanced Raman scattering (SERS), which integrates high chemical sensitivity with spectroscopic identification and has enormous potential for applications involving ultra-sensitive chemical detection. Spectra were obtained using a Renishaw RM2000 Raman Microspectrometer system operating in the visible region excitation (532 nm).

  8. Frequencies of heavy metal resistance are associated with land cover type in the Upper Mississippi River.

    PubMed

    Staley, Christopher; Johnson, Dylan; Gould, Trevor J; Wang, Ping; Phillips, Jane; Cotner, James B; Sadowsky, Michael J

    2015-04-01

    Taxonomic compositions of freshwater bacterial communities have been well-characterized via metagenomic and amplicon-based approaches, especially next-generation sequencing. However, functional diversity of these communities remains less well-studied. Various anthropogenic sources are known to impact the bacterial community composition in freshwater riverine systems and potentially alter functional diversity. In this study, high-throughput functional screening of large (~10,000 clones) fosmid libraries representing communities in the Upper Mississippi River revealed low frequencies of resistance to heavy metals in the following order: Mn2+>Cr3+>Zn2+>Cd2+>Hg2+. No resistance to Cu2+ was detected. Significant, but weak, correlations were observed between resistance frequencies of Cd and Cr with developed land cover (r2=0.08, P=0.016 and r=0.07, P=0.037, respectively). While discriminant function analyses further supported these associations, redundancy analysis further indicated associations with forested land cover and greater resistance to Hg and Zn. Nutrient and metal ion concentrations and abundances of bacterial orders were poorly correlated with heavy metal resistance, except for an association of Pseudomonadales abundance and resistance to Hg and Zn. Taken together, results of this study suggest that allochthonous bacteria contributed from specific land cover types influence the patterns of metal resistance throughout this river.

  9. Flexible and hydrophobic Zn-based metal-organic framework.

    PubMed

    Hauptvogel, Ines Maria; Biedermann, Ralf; Klein, Nicole; Senkovska, Irena; Cadiau, Amandine; Wallacher, Dirk; Feyerherm, Ralf; Kaskel, Stefan

    2011-09-05

    A zinc-based metal-organic framework Zn(2)(adb)(2)(dabco)·4.5 DMF (K) (DUT-30(Zn), DUT = Dresden University of Technology, adb = 9,10-anthracene dibenzoate, dabco =1,4-diazabicyclo[2.2.2]octane, DMF = N,N-dimethylformamide) was synthesized using a solvothermal route. This MOF exhibits six crystallographic guest dependent phases. Two of them were characterized via single crystal X-ray analysis. The as-synthesized phase K crystallizes in the orthorhombic space group Fmmm, with a = 9.6349(9), b = 26.235(3), and c = 28.821(4) Å and consists of two interpenetrated pillar-layer networks with pcu topology. When the substance loses 0.5 DMF molecules per formula unit, a phase transition from the kinetic phase K to a thermodynamic phase T occurs. Zn(2)(adb)(2)(dabco)·4 DMF (T) crystallizes in the tetragonal space group I4/mmm, with a = 19.5316(8) and c = 9.6779(3) Å. During the evacuation the DUT-30(Zn) undergoes again the structural transformation to A. The activated compound A shows the gate pressure effect in the low pressure region of nitrogen physisorption isotherm and has a BET surface area of 960 m(2 )g(-1) and a specific pore volume of 0.43 cm(3) g(-1). Furthermore, DUT-30(Zn) exhibits a hydrogen storage capacity of 1.12 wt % at 1 bar, a CO(2) uptake of 200 cm(3) g(-1) at -78 °C and 0.9 bar, and a n-butane uptake of 3.0 mmol·g(-1) at 20 °C. The N(2) adsorption process was monitored in situ via X-ray powder diffraction using synchrotron radiation. A low temperature induced transformation of phase A to phase V could be observed if the compound was cooled under vacuum to -196 °C. A further crystalline phase N could be identified if the framework was filled with nitrogen at -196 °C. Additionally, the treatment of activated phase A with water leads to the new phase W.

  10. Functional Design of Dielectric-Metal-Dielectric-Based Thin-Film Encapsulation with Heat Transfer and Flexibility for Flexible Displays.

    PubMed

    Kwon, Jeong Hyun; Choi, Seungyeop; Jeon, Yongmin; Kim, Hyuncheol; Chang, Ki Soo; Choi, Kyung Cheol

    2017-08-16

    In this study, a new and efficient dielectric-metal-dielectric-based thin-film encapsulation (DMD-TFE) with an inserted Ag thin film is proposed to guarantee the reliability of flexible displays by improving the barrier properties, mechanical flexibility, and heat dissipation, which are considered to be essential requirements for organic light-emitting diode (OLED) encapsulation. The DMD-TFE, which is composed of Al2O3, Ag, and a silica nanoparticle-embedded sol-gel hybrid nanocomposite, shows a water vapor transmission rate of 8.70 × 10(-6) g/m(2)/day and good mechanical reliability at a bending radius of 30 mm, corresponding to 0.41% strain for 1000 bending cycles. The electrical performance of a thin-film encapsulated phosphorescent organic light-emitting diode (PHOLED) was identical to that of a glass-lid encapsulated PHOLED. The operational lifetimes of the thin-film encapsulated and glass-lid encapsulated PHOLEDs are 832 and 754 h, respectively. After 80 days, the thin-film encapsulated PHOLED did not show performance degradation or dark spots on the cell image in a shelf-lifetime test. Finally, the difference in lifetime of the OLED devices in relation to the presence and thickness of a Ag film was analyzed by applying various TFE structures to fluorescent organic light-emitting diodes (FOLEDs) that could generate high amounts of heat. To demonstrate the difference in heat dissipation effect among the TFE structures, the saturated temperatures of the encapsulated FOLEDs were measured from the back side surface of the glass substrate, and were found to be 67.78, 65.12, 60.44, and 39.67 °C after all encapsulated FOLEDs were operated at an initial luminance of 10 000 cd/m(2) for sufficient heat generation. Furthermore, the operational lifetime tests of the encapsulated FOLED devices showed results that were consistent with the measurements of real-time temperature profiles taken with an infrared camera. A multifunctional hybrid thin-film encapsulation based

  11. Surface-grafted polymer-assisted electroless deposition of metals for flexible and stretchable electronics.

    PubMed

    Liu, Xuqing; Zhou, Xuechang; Li, Yi; Zheng, Zijian

    2012-05-01

    Surface-grafted polymers, that is, ultrathin layers of polymer coating covalently tethered to a surface, can serve as a particularly promising nanoplatform for electroless deposition (ELD) of metal thin films and patterned structures. Such polymers consist of a large number of well-defined binding sites for highly efficient and selective uptake of ELD catalysts. Moreover, the polymer chains provide flexible 3D network structures to trap the electrolessly deposited metal particles, leading to strong metal-substrate adhesion. In the past decade, surface-grafted polymers have been demonstrated as efficient nanoplatforms for fabricating durable and high-performance metal coatings by ELD on plastic substrates for applications in flexible and stretchable electronics. This focus review summarizes these recent advances, with a particular focus on applications in polymeric flexible and stretchable substrates. An outlook on the future challenges and opportunities in this field is given at the end of this paper. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Direct writing of flexible electronics through room temperature liquid metal ink.

    PubMed

    Gao, Yunxia; Li, Haiyan; Liu, Jing

    2012-01-01

    Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn(10)-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way. The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements. The electrical resistivity of the fluid like GaIn(10)-based material was measured as 34.5 µΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 µm thick. Several functional devices such as a light emitting diode (LED) array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained. The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn(10)-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized purpose and can be extended to more industrial areas, even

  13. Direct Writing of Flexible Electronics through Room Temperature Liquid Metal Ink

    PubMed Central

    Gao, Yunxia; Li, Haiyan; Liu, Jing

    2012-01-01

    Background Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn10-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way. Methods The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements. Results The electrical resistivity of the fluid like GaIn10-based material was measured as 34.5 µΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 µm thick. Several functional devices such as a light emitting diode (LED) array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained. Conclusions The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn10-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized purpose and can be

  14. Metal-Phenolic Carbon Nanocomposites for Robust and Flexible Energy-Storage Devices.

    PubMed

    Oh, Jun Young; Jung, Yeonsu; Cho, Young Shik; Choi, Jaeyoo; Youk, Ji Ho; Fechler, Nina; Yang, Seung Jae; Park, Chong Rae

    2017-04-22

    Future electronics applications such as wearable electronics depend on the successful construction of energy-storage devices with superior flexibility and high electrochemical performance. However, these prerequisites are challenging to combine: External forces often cause performance degradation, whereas the trade-off between the required nanostructures for strength and electrochemical performance only results in diminished energy storage. Herein, a flexible supercapacitor based on tannic acid (TA) and carbon nanotubes (CNTs) with a unique nanostructure is presented. TA was self-assembled on the surface of the CNTs by metal-phenolic coordination bonds, which provides the hybrid film with both high strength and high pseudocapacitance. Besides 17-fold increased mechanical strength of the final composite, the hybrid film simultaneously exhibits excellent flexibility and volumetric capacitance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Hydrogen storage in Pd nanocrystals covered with a metal-organic framework

    NASA Astrophysics Data System (ADS)

    Li, Guangqin; Kobayashi, Hirokazu; Taylor, Jared M.; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Toh, Shoichi; Matsumura, Syo; Kitagawa, Hiroshi

    2014-08-01

    Hydrogen is an essential component in many industrial processes. As a result of the recent increase in the development of shale gas, steam reforming of shale gas has received considerable attention as a major source of H2, and the more efficient use of hydrogen is strongly demanded. Palladium is well known as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Here, we present remarkably enhanced capacity and speed of hydrogen storage in Pd nanocrystals covered with the metal-organic framework (MOF) HKUST-1 (copper(II) 1,3,5-benzenetricarboxylate). The Pd nanocrystals covered with the MOF have twice the storage capacity of the bare Pd nanocrystals. The significantly enhanced hydrogen storage capacity was confirmed by hydrogen pressure-composition isotherms and solid-state deuterium nuclear magnetic resonance measurements. The speed of hydrogen absorption in the Pd nanocrystals is also enhanced by the MOF coating.

  16. Hydrogen storage in Pd nanocrystals covered with a metal-organic framework.

    PubMed

    Li, Guangqin; Kobayashi, Hirokazu; Taylor, Jared M; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Toh, Shoichi; Matsumura, Syo; Kitagawa, Hiroshi

    2014-08-01

    Hydrogen is an essential component in many industrial processes. As a result of the recent increase in the development of shale gas, steam reforming of shale gas has received considerable attention as a major source of H2, and the more efficient use of hydrogen is strongly demanded. Palladium is well known as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Here, we present remarkably enhanced capacity and speed of hydrogen storage in Pd nanocrystals covered with the metal-organic framework (MOF) HKUST-1 (copper(II) 1,3,5-benzenetricarboxylate). The Pd nanocrystals covered with the MOF have twice the storage capacity of the bare Pd nanocrystals. The significantly enhanced hydrogen storage capacity was confirmed by hydrogen pressure-composition isotherms and solid-state deuterium nuclear magnetic resonance measurements. The speed of hydrogen absorption in the Pd nanocrystals is also enhanced by the MOF coating.

  17. Covered metal stents in endoscopic therapy of biliary complications after liver transplantation.

    PubMed

    Cantù, Paolo; Tenca, Andrea; Parzanese, Ilaria; Penagini, Roberto

    2016-08-01

    There is growing interest in using covered self-expandable metal stents for the treatment of benign biliary conditions, and the presence of anastomotic biliary strictures and leaks after liver transplantation provide a valuable opportunity for testing them. The performance of the stents is encouraging, and the technical success rate is high. They provide larger diameter dilation and are easily removed, and can potentially limit costs by reducing the number of procedures needed to treat anastomotic biliary strictures. However, drawbacks such as sub-optimal tolerability and migration may affect both patient management and costs. New stent designs are currently being evaluated. Randomized controlled trials and cost-effectiveness analyses comparing covered metal stents with multiple plastic stent endotherapy are warranted in order to define the role of the former as first-line or rescue treatment. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  18. Fully-covered metallic stenting in an infant with tracheoesophageal fistula due to button battery ingestion.

    PubMed

    Zhang, Zhongxiao; Ma, Jing; Liu, Shuaishuai; Liu, Xia; Yan, Xiuli; Niu, Tiehuan; Li, Changxiao; Li, Qian; Wang, Chao; Meng, Chen

    2017-04-01

    Previously, the main treatment options for tracheoesophageal fistula included surgery and conservative treatment. Herein, we report a child suffering from severe tracheoesophageal fistula due to button battery ingestion. The child relapsed soon after a repair surgery. Then, he was endotracheally implanted with a fully-covered metallic stent combined with a jejunal tube feeding. He recovered soon and the stent was removed five months later. The fistula was healed with no relapse during a 25-month follow-up. Therefore, endotracheal implantation of fully-covered metallic stent is an alternative treatment for tracheoesophageal fistula due to button battery ingestion, especially in cases with severe respiratory disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Field-induced activation of metal oxide semiconductor for low temperature flexible transparent electronic device applications

    NASA Astrophysics Data System (ADS)

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony; Haglund, Amada; Ward, Thomas Zac; Mandrus, David; Rack, Philip

    Amorphous metal-oxide semiconductors have been extensively studied as an active channel material in thin film transistors due to their high carrier mobility, and excellent large-area uniformity. Here, we report the athermal activation of amorphous indium gallium zinc oxide semiconductor channels by an electric field-induced oxygen migration via gating through an ionic liquid. Using field-induced activation, a transparent flexible thin film transistor is demonstrated on a polyamide substrate with transistor characteristics having a current ON-OFF ratio exceeding 108, and saturation field effect mobility of 8.32 cm2/(V.s) without a post-deposition thermal treatment. This study demonstrates the potential of field-induced activation as an athermal alternative to traditional post-deposition thermal annealing for metal oxide electronic devices suitable for transparent and flexible polymer substrates. Materials Science and Technology Division, ORBL, Oak Ridge, TN 37831, USA.

  20. Large-scale fabrication of flexible metallic nanostructure pairs using interference ablation.

    PubMed

    Zhai, Tianrui; Wang, Yonglu; Liu, Hongmei; Zhang, Xinping

    2015-01-26

    Paired one- and two-dimensional metallic nanostructures are created directly by exposing a thin gold film to the interference pattern between ultraviolet laser pulses, where the gold film is coated onto a soft substrate and is sandwiched by another soft slab. Metallic films in the bright fringes are melted and transformed into nanodroplets that are ejected onto the soft slab forming stretchable nanoisland structures. The pattern of the remaining films is coincident with the dark fringes. Thus, complementary metallic nanostructure pairs were fabricated using a single laser pulse. Fano resonance can be observed in the spectroscopic response of the fabricated nanostructures for TM and TE polarizations simultaneously. This nanofabrication technique may provide an annealing-free approach for the fabrication of flexible metallic nanostructures on a large scale and with low cost.

  1. Ionic Liquid Activation of Amorphous Metal-Oxide Semiconductors for Flexible Transparent Electronic Devices

    DOE PAGES

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony T.; ...

    2016-02-09

    To begin this abstract, amorphous metal-oxide semiconductors offer the high carrier mobilities and excellent large-area uniformity required for high performance, transparent, flexible electronic devices; however, a critical bottleneck to their widespread implementation is the need to activate these materials at high temperatures which are not compatible with flexible polymer substrates. The highly controllable activation of amorphous indium gallium zinc oxide semiconductor channels using ionic liquid gating at room temperature is reported. Activation is controlled by electric field-induced oxygen migration across the ionic liquid-semiconductor interface. In addition to activation of unannealed devices, it is shown that threshold voltages of a transistormore » can be linearly tuned between the enhancement and depletion modes. Finally, the first ever example of transparent flexible thin film metal oxide transistor on a polyamide substrate created using this simple technique is demonstrated. Finally, this study demonstrates the potential of field-induced activation as a promising alternative to traditional postdeposition thermal annealing which opens the door to wide scale implementation into flexible electronic applications.« less

  2. Ionic Liquid Activation of Amorphous Metal-Oxide Semiconductors for Flexible Transparent Electronic Devices

    SciTech Connect

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony T.; Ovchinnikova, Olga S.; Haglund, Amanda V.; Dai, Sheng; Ward, Thomas Zac; Mandrus, David; Rack, Philip D.

    2016-02-09

    To begin this abstract, amorphous metal-oxide semiconductors offer the high carrier mobilities and excellent large-area uniformity required for high performance, transparent, flexible electronic devices; however, a critical bottleneck to their widespread implementation is the need to activate these materials at high temperatures which are not compatible with flexible polymer substrates. The highly controllable activation of amorphous indium gallium zinc oxide semiconductor channels using ionic liquid gating at room temperature is reported. Activation is controlled by electric field-induced oxygen migration across the ionic liquid-semiconductor interface. In addition to activation of unannealed devices, it is shown that threshold voltages of a transistor can be linearly tuned between the enhancement and depletion modes. Finally, the first ever example of transparent flexible thin film metal oxide transistor on a polyamide substrate created using this simple technique is demonstrated. Finally, this study demonstrates the potential of field-induced activation as a promising alternative to traditional postdeposition thermal annealing which opens the door to wide scale implementation into flexible electronic applications.

  3. The biodurability of covering materials for metallic stents in a bile flow phantom.

    PubMed

    Bang, Byoung Wook; Jeong, Seok; Lee, Don Haeng; Lee, Jung Il; Lee, Se Chul; Kang, Sung-Gwon

    2012-04-01

    Covered biliary metal stents have been introduced for the purpose of overcoming tumor ingrowth and treatment of benign biliary stricture. The aim of this study was to evaluate the biodurability of three commercially available biliary metal stent covering materials [e-PTFE (expanded polytetrafluoroethylene), silicone, and polyurethane] in a bile flow phantom. By operation of a peristaltic pump, human bile was circulated continuously in an experimental perfusion system containing covered metal stents. Each stent was removed, respectively, 1, 2, 4, and 6 months after bile exposure. We performed a gross inspection of the covered stents. The covering membrane was detached from the stent and observed by scanning electron microscopy (SEM). Finally, we measured tensile and tear strength of the membranes. Bile-staining of the membrane showed gradual progression after bile exposure; however, progress was the fastest in e-PTFE. SEM examination showed that the polyurethane surface was smooth, and the silicone surface was relatively smooth. However, e-PTFE had a rough and uneven surface. After bile exposure, there were no significant changes in polyurethane and silicone; however, biofilms and microcracks were observed in e-PTFE. In contrast to a gradual decrease of tensile/tear strength of polyurethane and silicone, those of e-PTFE showed a rapid reduction despite of the strongest baseline tensile and tear strength. e-PTFE tended to form biofilms more frequently than polyurethane and silicone during bile exposure. e-PTFE seemed to be less durable than silicone and polyurethane, however, as clinically applicable material because of strong absolute tensile/tear strengths.

  4. Fast Fabrication of Flexible Functional Circuits Based on Liquid Metal Dual-Trans Printing.

    PubMed

    Wang, Qian; Yu, Yang; Yang, Jun; Liu, Jing

    2015-11-25

    A dual-trans method to print the first functional liquid-metal circuit layout on poly(vinyl chloride) film, and then transfer it into a poly(dimethylsiloxane) substrate through freeze phase transition processing for the fabrication of a flexible electronic device. A programmable soft electronic band and a temperature-sensing module wirelessly communicate with a mobile phone, demonstrating the efficiency and capability of the method. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water

    DTIC Science & Technology

    2016-03-01

    A Small arms firing ranges (SAFRs) located on Department of Defense (DoD) facilities are, in many cases, constructed next to wetland areas...including ponds, lakes, and streams. These wetlands , which may be seasonal, intermittent, freshwater, brackish, or estuarine, represent a potential point of...project is designated as ESTCP Project ER-201213: A Flexible Permeable Reactive Barrier for Protection of Wetland Sediments from Heavy Metals in Runoff

  6. Retinal Stimulation on Rabbit Using Complementary Metal Oxide Semiconductor Based Multichip Flexible Stimulator toward Retinal Prosthesis

    NASA Astrophysics Data System (ADS)

    Tokuda, Takashi; Asano, Ryosuke; Sugitani, Sachie; Taniyama, Mari; Terasawa, Yasuo; Nunoshita, Masahiro; Nakauchi, Kazuaki; Fujikado, Takashi; Tano, Yasuo; Ohta, Jun

    2008-04-01

    The Functionality of a complementary metal oxide semiconductor (CMOS) LSI-based, multichip flexible retinal stimulator was demonstrated in retinal stimulation experiments on rabbits. A 1×4-configured multichip stimulator was fabricated for application to experiments on animals. An experimental procedure including surgical operations was developed, and retinal stimulation was performed with the fabricated multichip stimulator. Neural responses on the visual cortex were successfully evoked by the fabricated stimulator. The stimulator is confirmed to be applicable to acute animal experiments.

  7. Development of a Flexible Non-Metal Electrode for Cell Stimulation and Recording

    PubMed Central

    Gong, Cihun-Siyong Alex; Syu, Wun-Jia; Lei, Kin Fong; Hwang, Yih-Shiou

    2016-01-01

    This study presents a method of producing flexible electrodes for potentially simultaneously stimulating and measuring cellular signals in retinal cells. Currently, most multi-electrode applications rely primarily on etching, but the metals involved have a certain degree of brittleness, leaving them prone to cracking under prolonged pressure. This study proposes using silver chloride ink as a conductive metal, and polydimethysiloxane (PDMS) as the substrate to provide electrodes with an increased degree of flexibility to allow them to bend. This structure is divided into the electrode layer made of PDMS and silver chloride ink, and a PDMS film coating layer. PDMS can be mixed in different proportions to modify the degree of rigidity. The proposed method involved three steps. The first segment entailed the manufacturing of the electrode, using silver chloride ink as the conductive material, and using computer software to define the electrode size and micro-engraving mechanisms to produce the electrode pattern. The resulting uniform PDMS pattern was then baked onto the model, and the flow channel was filled with the conductive material before air drying to produce the required electrode. In the second stage, we tested the electrode, using an impedance analyzer to measure electrode cyclic voltammetry and impedance. In the third phase, mechanical and biocompatibility tests were conducted to determine electrode properties. This study aims to produce a flexible, non-metallic sensing electrode which fits snugly for use in a range of measurement applications. PMID:27690049

  8. Very long Ag nanowire synthesis and its application in a highly transparent, conductive and flexible metal electrode touch panel.

    PubMed

    Lee, Jinhwan; Lee, Phillip; Lee, Hyungman; Lee, Dongjin; Lee, Seung Seob; Ko, Seung Hwan

    2012-10-21

    The future electronics will be soft, flexible and even stretchable to be more human friendly in the form of wearable computers. However, conventional electronic materials are usually brittle. Recently, carbon based materials are intensively investigated as a good candidate for flexible electronics but with limited mechanical and electrical performances. Metal is still the best material for electronics with great electrical properties but with poor transparency and mechanical performance. Here we present a simple approach to develop a synthesis method for very long metallic nanowires and apply them as new types of high performance flexible and transparent metal conductors as an alternative to carbon nanotubes, graphene and short nanowire based flexible transparent conductors and indium tin oxide based brittle transparent conductors. We found that very long metallic nanowire network conductors combined with a low temperature laser nano-welding process enabled superior transparent flexible conductors with high transmittance and high electrical conductivity. Further, we demonstrated highly flexible metal conductor LED circuits and transparent touch panels. The highly flexible and transparent metal conductors can be mounted on any non-planar surfaces and applied for various opto-electronics and ultimately for future wearable electronics.

  9. [Sealing of airway fistulas for metallic covered z-type stents].

    PubMed

    Wang, Hongwu; Li, Dongmei; Zhang, Nan; Zou, Hang; Luo, Lingfei; Ma, Hongming; Zhou, Yunzhi; Li, Jing; Liang, Sujuan

    2011-08-01

    Treating airway fistulas, including esophagorespiratory fistulas (ERFs), bronchopleural fistulas (BPFs), and tracheomediastinal fistulas (TMFs), is difficult. The aim of this study is to evaluate the safety and clinical efficacy of metallic covered Z-type stents (CZTS) for the treatment of airway fistulas through bronchoscopy or fluroscopy. Thirty-eight patients with fistulas between the esophagus, mediastina, and airways (32 ERFs, 5 BPFs, and 1 TMF) were retrospectively reviewed after treatment with covered metallic esophageal and airway stents. The fistulas were caused by esophageal (n=26), bronchogenic (n=11), and thyroid (n=1) carcinomas. Forty-six fistulas were found in 38 patients. The fistula size ranged from 0.5 cm to 7.0 cm. Forty airway covered metal stents (24 Y-type, 8 L-type, and 8 I-type) and 24 esophageal metal stents were placed. Complete responses to the sealing effects of fistulas were noted in 4.3% of all the fistulas, 60.9% showed complete clinical responses, 23.9% showed partial responses, and 10.9% showed no response. An effectivity rate of 89.1% was observed, and the median survival duration of all patients was 5 months. The use of CZTS appears to be safe and feasible for the palliative treatment of ERFs, BPFs, and TMFs. Airway stent placement is recommended for patients with ERF. In the event that airway stents fail, esophageal stents should be given. Airway bifurcation stents were observed to be especially suitable for the sealing of fistulas near the trachea carina.

  10. Clinical remission following endoscopic placement of retrievable, fully covered metal stents in patients with esophageal achalasia.

    PubMed

    Zeng, Y; Dai, Y-M; Wan, X-J

    2014-01-01

    Metal stents may represent an alternative therapy in the treatment of achalasia. We therefore evaluated the effectiveness of retrievable, fully covered metal stents in patients with achalasia. Fifty-nine patients with achalasia were treated with retrievable, fully covered metal stents. Symptoms using a global symptom score (0-10), lower esophageal sphincter (LES) resting pressure, LES relaxation, and simultaneous contraction of the esophagus were analyzed before and 1 week and 1 month after intervention. Complications and treatment outcomes were followed up at 6, 12, 18, and 24 months postoperatively. Stent placement was successful, and clinical symptoms resolved (P < 0.01) in all patients. Regurgitation, dysphagia and chest pain improved significantly (all P < 0.01). Therapy improved LES resting pressure (51.4 ± 9.7 mmHg pretherapy vs. 20.9 ± 8.1 mmHg post-therapy), LES relaxation (58.1 ± 17.1% pretherapy vs. 84.5 ± 18.9% post-therapy), and simultaneous contraction of the esophagus (36.1 ± 8.6% pretherapy vs. 69.4 ± 23.1% post-therapy) 1 month after stent placement (all P < 0.01). The cumulative clinical remission rates 6, 12, 18, 24, 30, and 36 months after stent removal were 90.9%, 81.8%, 76.4%, 69.1%, 65.5%, and 49.1%, respectively. All patients tolerated stent placement. Twelve patients (25.5%) complained of substernal pain and five (10.6%) had substernal burning. Stents migrated in four patients (8.5%). Insertion of retrievable, fully covered metal stents is an effective and safe treatment in patients with achalasia.

  11. Impermeable flexible liquid barrier film for encapsulation of DSSC metal electrodes

    NASA Astrophysics Data System (ADS)

    Yang, Junghee; Min, Misook; Yoon, Yeoheung; Kim, Won Jung; Kim, Sol; Lee, Hyoyoung

    2016-06-01

    Encapsulation of electronic devices such as dye-sensitized solar cells (DSSCs) is prone to degradation under normal atmospheric conditions, even with hermetic barriers on the metal electrodes. Overcoming this problem is crucial to increasing DSSC lifetimes and making them commercially viable. Herein, we report a new impermeable flexible liquid barrier film using polyvinyl alcohol (PVA) and partially reduced graphene oxide (PrGO), which dramatically enhances the lifetime of Ag metal electrodes (typically used in DSSCs) immersed in a highly acidic iodolyte solution. The Ag metal electrode encapsulated by the PVA/PrGO film survived for over 500 hrs, superior to existing barriers of glass frits, epoxy resins and polymers. The PVA/PrGO film strongly adheres to the Ag metal surface, and the resulting PVA/PrGO/Ag electrode is stable even on a curved substrate, with a sheet resistance nearly independent of curvature. These results give new insight for the design of high-performance and solution-processable flexible liquid barrier films for a wide range of applications, in particular for the encapsulation of electronic devices with liquid electrolytes.

  12. Impermeable flexible liquid barrier film for encapsulation of DSSC metal electrodes

    PubMed Central

    Yang, Junghee; Min, Misook; Yoon, Yeoheung; Kim, Won Jung; Kim, Sol; Lee, Hyoyoung

    2016-01-01

    Encapsulation of electronic devices such as dye-sensitized solar cells (DSSCs) is prone to degradation under normal atmospheric conditions, even with hermetic barriers on the metal electrodes. Overcoming this problem is crucial to increasing DSSC lifetimes and making them commercially viable. Herein, we report a new impermeable flexible liquid barrier film using polyvinyl alcohol (PVA) and partially reduced graphene oxide (PrGO), which dramatically enhances the lifetime of Ag metal electrodes (typically used in DSSCs) immersed in a highly acidic iodolyte solution. The Ag metal electrode encapsulated by the PVA/PrGO film survived for over 500 hrs, superior to existing barriers of glass frits, epoxy resins and polymers. The PVA/PrGO film strongly adheres to the Ag metal surface, and the resulting PVA/PrGO/Ag electrode is stable even on a curved substrate, with a sheet resistance nearly independent of curvature. These results give new insight for the design of high-performance and solution-processable flexible liquid barrier films for a wide range of applications, in particular for the encapsulation of electronic devices with liquid electrolytes. PMID:27263654

  13. Comparison of a New Polytetrafluoroethylene-Covered Metallic Stent to a Noncovered Stent in Canine Ureters

    SciTech Connect

    Chung, Hwan-Hoon Lee, Seung Hwa; Cho, Sung Bum; Park, Hong Suk; Kim, Young Sik; Kang, Byung Chul; Frisoli, Joan K.; Razavi, Mahmood K.

    2008-05-15

    The aim of this study was to determine the feasibility of using a newly designed polytetrafluoroethylene (PTFE)-covered metallic stent in the ureter by comparing its effectiveness with that of the noncovered stent in a canine model. We placed 14 stents in the ureters of seven mongrel dogs that weighed 30-40 kg each. The covered and noncovered stents were deployed in the right and left ureters, respectively, of six dogs. In the seventh dog, a covered stent and a double-J catheter were inserted in the right ureter, and a covered stent only was inserted in the left ureter. The first six dogs were sacrificed at 5, 10, and 15 weeks after deployment of the stents (two for each follow-up period), and the seventh dog was sacrificed at 30 weeks. There was no migration or poor expansion of any of the stents observed on plain radiography. On intravenous pyelogram and retrograde pyelogram, all of the covered stents at each follow-up period had patent lumens at the stented segments without hydronephrosis, and the passage of contrast material through it was well preserved. The noncovered stents in the dogs sacrificed at 5 and 10 weeks and one of the two dogs sacrificed at 15 weeks showed near-complete occlusion of the stent lumen due to ingrowth of the soft tissue, and severe hydronephrosis was also noted. The noncovered stent in the other dog sacrificed at 15 weeks showed the passage of contrast material without hydronephrosis, but the lumen of the stent was still nearly occluded by the soft tissue. There was no evidence of hydronephrosis or passage disturbance of the contrast material in both ureters of the dog sacrificed at 30 weeks. We conclude that the newly designed PTFE-covered stent effectively prevented the luminal occlusion caused by urothelial hyperplasia compared to the near-total occlusion of the noncovered stents, and no migration of the covered stents was noted.

  14. Impact of anticancer treatment on recurrent obstruction in covered metallic stents for malignant biliary obstruction.

    PubMed

    Nakai, Yousuke; Isayama, Hiroyuki; Mukai, Tsuyoshi; Itoi, Takao; Maetani, Iruru; Kawakami, Hiroshi; Yasuda, Ichiro; Maguchi, Hiroyuki; Ryozawa, Shomei; Hanada, Keiji; Hasebe, Osamu; Ito, Kei; Kawamoto, Hiorofumi; Mochizuki, Hitoshi; Igarashi, Yoshinori; Irisawa, Atsushi; Sasaki, Tamito; Togawa, Osamu; Hara, Taro; Kamada, Hideki; Toda, Nobuo; Hamada, Tsuyoshi; Kogure, Hirofumi

    2013-11-01

    In patients with unresectable malignant biliary obstruction (MBO), anticancer treatment is often administered. The impact of anticancer treatment on recurrent biliary obstruction in covered self-expandable metallic stents (SEMS) has not been fully elucidated. Data on 279 patients enrolled in a multicenter prospective cohort study of two different covered SEMS for distal MBO, WATCH study (141 partially covered WallFlex stents and 138 partially covered Wallstents) were retrospectively analyzed. The rates and causes of recurrent biliary obstruction (stent occlusion or migration) were compared between anticancer treatment group (n = 173) and best supportive care alone (BSC) group (n = 106). Cumulative time and prognostic factors for recurrent biliary obstruction were analyzed, using a proportional hazards model with death without recurrent biliary obstruction as a competing risk. The overall rate (43 vs. 25%, P = 0.002) and the cumulative incidence (16.1 vs. 8.2, 27.9 vs. 18.9 and 44.1 vs. 26.6% at 3, 6 and 12 months, P = 0.030 by Gray's test) of recurrent biliary obstruction were significantly higher in anticancer treatment group compared with BSC group. The multivariate analysis revealed anticancer treatment [subdistribution hazard ratio (SHR) 1.93, P = 0.007) as well as the use of a partially covered WallFlex stent (SHR 0.65, P = 0.049) as prognostic factors. Anticancer treatment was a risk factor for recurrent biliary obstruction in covered SEMS for distal MBO. The superiority of a partially covered WallFlex stent was again confirmed in this competing risk analysis; UMIN-CTR: UMIN000002293.

  15. Endoscopic treatment of benign biliary strictures using covered self-expandable metal stents (CSEMS).

    PubMed

    Irani, Shayan; Baron, Todd H; Akbar, Ali; Lin, Otto S; Gluck, Michael; Gan, Ian; Ross, Andrew S; Petersen, Bret T; Topazian, Mark; Kozarek, Richard A

    2014-01-01

    Traditional endoscopic management of benign biliary strictures (BBS) consists of placement of one or more plastic stents. Emerging data support the use of covered self-expandable metal stents (CSEMS). We sought to assess outcome of endoscopic temporary placement of CSEMS in patients with BBS. This was a retrospective study of CSEMS placement for BBS between May 2005 and July 2012 from two tertiary care centers. A total of 145 patients (81 males, median age 59 years) with BBS were identified; 73 of which were classified as extrinsic and were caused by chronic pancreatitis, and 70 were intrinsic. Main outcome measures were resolution of stricture and adverse events (AEs) due to self-expandable metal stents (SEMS)-related therapy. Fully covered and partially covered 8-10 mm diameter SEMS were placed and subsequently removed in 121/125 (97 %) attempts in BBS (failure to remove four partially covered stents). Stricture resolution occurred in 83/125 (66 %) patients after a median stent duration of 26 weeks (median follow-up 90 weeks). Resolution of extrinsic strictures was significantly lower compared to intrinsic strictures (31/65, 48 % vs. 52/60, 87 %, p = 0.004) despite longer median stent duration (30 vs. 20 weeks). Thirty-seven AEs occurred in 25 patients (17 %), with 12 developing multiple AEs including cholangitis (n = 17), pancreatitis (n = 5), proximal stent migration (n = 3), cholecystitis (n = 2), pain requiring SEMS removal and/or hospitalization (n = 3), inability to remove (n = 4), and new stricture formation (n = 3). Benign biliary strictures can be effectively treated with CSEMS. Successful resolution of biliary strictures due to extrinsic disease is seen significantly less often than those due to intrinsic disease. Removal is successful in all patients with fully covered SEMS.

  16. Structural Flexibility and Alloying in Ultrathin Transition-Metal Chalcogenide Nanowires

    DOE PAGES

    Lin, Junhao; Zhang, Yuyang; Zhou, Wu; ...

    2016-01-18

    Metallic transition-metal chalcogenide (TMC) nanowires are an important building block for 2D electronics that may be fabricated within semiconducting transition-metal dichalcogenide (TMDC) monolayers. Tuning the geometric structure and electronic properties of such nanowires is a promising way to pattern diverse functional channels for wiring multiple units inside a 2D electronic circuit. Nevertheless, few experimental investigations have been reported exploring the structural and compositional tunability of these nanowires, due to difficulties in manipulating the structure and chemical composition of an individual nanowire. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we report that TMCmore » nanowires have substantial intrinsic structural flexibility and their chemical composition can be manipulated.« less

  17. Structural Flexibility and Alloying in Ultrathin Transition-Metal Chalcogenide Nanowires

    SciTech Connect

    Lin, Junhao; Zhang, Yuyang; Zhou, Wu; Pantelides, Sokrates T.

    2016-01-18

    Metallic transition-metal chalcogenide (TMC) nanowires are an important building block for 2D electronics that may be fabricated within semiconducting transition-metal dichalcogenide (TMDC) monolayers. Tuning the geometric structure and electronic properties of such nanowires is a promising way to pattern diverse functional channels for wiring multiple units inside a 2D electronic circuit. Nevertheless, few experimental investigations have been reported exploring the structural and compositional tunability of these nanowires, due to difficulties in manipulating the structure and chemical composition of an individual nanowire. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we report that TMC nanowires have substantial intrinsic structural flexibility and their chemical composition can be manipulated.

  18. Selective Gold Recovery and Catalysis in a Highly Flexible Methionine-Decorated Metal-Organic Framework.

    PubMed

    Mon, Marta; Ferrando-Soria, Jesús; Grancha, Thais; Fortea-Pérez, Francisco R; Gascon, Jorge; Leyva-Pérez, Antonio; Armentano, Donatella; Pardo, Emilio

    2016-06-29

    A novel chiral 3D bioMOF exhibiting functional channels with thio-alkyl chains derived from the natural amino acid l-methionine (1) has been rationally prepared. The well-known strong affinity of gold for sulfur derivatives, together with the extremely high flexibility of the thioether "arms" decorating the channels, account for a selective capture of gold(III) and gold(I) salts in the presence of other metal cations typically found in electronic wastes. The X-ray single-crystal structures of the different gold adsorbates Au(III)@1 and Au(I)@1 suggest that the selective metal capture occurs in a metal ion recognition process somehow mimicking what happens in biological systems and protein receptors. Both Au(III)@1 and Au(I)@1 display high activity as heterogeneous catalyst for the hydroalkoxylation of alkynes, further expanding the application of these novel hybrid materials.

  19. New approach for fabricating hybrid-structured metal mesh films for flexible transparent electrodes by the combination of electrospinning and metal deposition

    NASA Astrophysics Data System (ADS)

    Huh, Jin Woo; Lee, Dong Kyu; Jeon, Hwan-Jin; Ahn, Chi Won

    2016-11-01

    In this study, hybrid-structured metal mesh (HMM) films as potential flexible transparent electrodes, composed of aligned micro-sized metal fibers integrated into random network of metal nanofibers, were fabricated by the combination of electrospinning and metal deposition. These naturally fiber-bridged HMMs, with a gold layer thickness of 85 nm, exhibited a high transmittance of around 90% and a sheet resistance of approximately 10 Ω sq-1, as well as favorable mechanical stability under bending stress. These results demonstrate that the approach employed herein is a simple, highly efficient, and facile process for fabricating, uniform, interconnected fiber networks with potential for producing high-performance flexible transparent electrodes.

  20. New approach for fabricating hybrid-structured metal mesh films for flexible transparent electrodes by the combination of electrospinning and metal deposition.

    PubMed

    Huh, Jin Woo; Lee, Dong Kyu; Jeon, Hwan-Jin; Ahn, Chi Won

    2016-11-25

    In this study, hybrid-structured metal mesh (HMM) films as potential flexible transparent electrodes, composed of aligned micro-sized metal fibers integrated into random network of metal nanofibers, were fabricated by the combination of electrospinning and metal deposition. These naturally fiber-bridged HMMs, with a gold layer thickness of 85 nm, exhibited a high transmittance of around 90% and a sheet resistance of approximately 10 Ω sq(-1), as well as favorable mechanical stability under bending stress. These results demonstrate that the approach employed herein is a simple, highly efficient, and facile process for fabricating, uniform, interconnected fiber networks with potential for producing high-performance flexible transparent electrodes.

  1. A flexible ligand-based wavy layered metal-organic framework for lithium-ion storage.

    PubMed

    An, Tiance; Wang, Yuhang; Tang, Jing; Wang, Yang; Zhang, Lijuan; Zheng, Gengfeng

    2015-05-01

    A substantial challenge for direct utilization of metal-organic frameworks (MOFs) as lithium-ion battery anodes is to maintain the rigid MOF structure during lithiation/delithiation cycles. In this work, we developed a flexible, wavy layered nickel-based MOF (C20H24Cl2N8Ni, designated as Ni-Me4bpz) by a solvothermal approach of 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2Me4bpz) with nickel(II) chloride hexahydrate. The obtained MOF materials (Ni-Me4bpz) with metal azolate coordination mode provide 2-dimensional layered structure for Li(+) intercalation/extraction, and the H2Me4bpz ligands allow for flexible rotation feature and structural stability. Lithium-ion battery anodes made of the Ni-Me4bpz material demonstrate excellent specific capacity and cycling performance, and the crystal structure is well preserved after the electrochemical tests, suggesting the potential of developing flexible layered MOFs for efficient and stable electrochemical storage. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Semitransparent and flexible perovskite solar cell with high visible transmittance based on ultrathin metallic electrodes.

    PubMed

    Ou, Xia-Li; Feng, Jing; Xu, Ming; Sun, Hong-Bo

    2017-05-15

    We have fabricated semitransparent and flexible indium-free perovskite solar cells (PeSCs) with high visible transmittance employing two kinds of composite ultrathin metallic electrodes, MoO3/Au and MoO3/Au/Ag/MoO3/Alq3, as the bottom and top electrodes, respectively. These electrodes show superb electrical conductivity, excellent mechanical robustness, and high optical transparency which are quite suitable for semitransparent and flexible PeSCs. An overall power conversion efficiency (PCE) of 6.96% and an average visible transmittance of 18.16% in the wavelength range of 380-790 nm were achieved. Furthermore, the devices maintained 71% of their initial PCE after 1000 bending cycles with a bending radius of 4 mm.

  3. Silver Nanowire Top Electrodes in Flexible Perovskite Solar Cells using Titanium Metal as Substrate.

    PubMed

    Lee, Minoh; Ko, Yohan; Min, Byoung Koun; Jun, Yongseok

    2016-01-08

    Flexible perovskite solar cells (FPSCs) have various applications such as wearable electronic textiles and portable devices. In this work, we demonstrate FPSCs on a titanium metal substrate employing solution-processed silver nanowires (Ag NWs) as the top electrode. The Ag NW electrodes were deposited on top of the spiro-MeOTAD hole transport layer by a carefully controlled spray-coating method at moderate temperatures. The power conversion efficiency (PCE) reached 7.45 % under AM 1.5 100 mW cm(-2) illumination. Moreover, the efficiency for titanium-based FPSCs decreased only slightly (by 2.6 % of the initial value) after the devices were bent 100 times. With this and other advances, fully solution-based indium-free flexible photovoltaics, advantageous in terms of price and processing, have the potential to be scaled into commercial production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Nanoaperture formation at metal covered tips by microspark optimized for near-field optical probes

    NASA Astrophysics Data System (ADS)

    Chaigneau, M.; Louarn, G.; Minea, T. M.

    2008-03-01

    A simple and reproducible method for nanoaperture opening of metal film covered tapered optical fibers is reported as the last step of the manufacturing process for near-field scanning optical microscopy (NSOM) probes. It uses a microspark between the biased tip and another plane electrode working as a coronalike discharge in point-to-plane configuration. The resultant high electric field is enhanced at the extremity of the metallized tip self-focusing the discharge ions. The opening process is performed in situ in a specially designed plasma reactor which also allows, for the optical fiber tips, their surface cleaning and silver coating. Nanoaperture diameter can be controlled between 30 and 100nm. These probes are able to generate subwavelength resolved images and are appropriate for high resolution NSOM.

  5. Hydrogen plasma induced photoelectron emission from low work function cesium covered metal surfaces

    NASA Astrophysics Data System (ADS)

    Laulainen, J.; Aleiferis, S.; Kalvas, T.; Koivisto, H.; Kronholm, R.; Tarvainen, O.

    2017-10-01

    Experimental results of hydrogen plasma induced photoelectron emission from cesium covered metal surfaces under ion source relevant conditions are reported. The transient photoelectron current during the Cs deposition process is measured from Mo, Al, Cu, Ta, Y, Ni, and stainless steel (SAE 304) surfaces. The photoelectron emission is 2-3.5 times higher at optimal Cs layer thickness in comparison to the clean substrate material. Emission from the thick layer of Cs is found to be 60%-80% lower than the emission from clean substrates.

  6. Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent.

    PubMed

    Chen, G; Wang, Z; Liang, X; Wang, Y; Wang, Y; Wang, Z; Xian, J

    2013-04-01

    To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Twenty-one patients with cuff-related tracheal stenosis, Meyer-Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh-Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4-12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent insertion and removal. An improvement in

  7. Mass Transfer of Nickel-Base Alloy Covered Electrode During Shielded Metal Arc Welding

    NASA Astrophysics Data System (ADS)

    Qin, Renyao; He, Guo

    2013-03-01

    The mass transfer in shielded metal arc welding of a group of nickel-base alloy covered electrodes according to AWS specification A5.11-A5.11M was investigated by directly measuring their deposited metal compositions. The results indicate that the chromium mass-transfer coefficient is in the range of 86 to 94 pct, iron in the range of 82 to 89 pct, manganese in the range of 60 to 73 pct, niobium in the range of 44 to 56 pct, and silicon in the range of 41 to 47 pct. The metal mass-transfer coefficient from the core wire is markedly higher than that from the coating. The basicity of slag, the metal contents in the flux coating, and the welding current together affect the mass transfer. As the basicity of slag increases, the mass-transfer coefficients of Mn, Fe, and Cr slightly increase, but those of Nb and Si decrease significantly. As the niobium and manganese contents increase in the coating, their mass-transfer coefficients also increase. However, iron is different. The content of iron in the coating in the range of 8 to 20 wt pct results in the optimal effective mass transfer. The lower, or higher, iron content leads to lower mass-transfer coefficient. As the welding current increases, the mass-transfer coefficients of niobium and manganese decrease, but chromium and silicon increase. Iron has the lowest mass-transfer coefficient when welded under the operating current of 100 A.

  8. Flexible strain sensors with high performance based on metallic glass thin film

    NASA Astrophysics Data System (ADS)

    Xian, H. J.; Cao, C. R.; Shi, J. A.; Zhu, X. S.; Hu, Y. C.; Huang, Y. F.; Meng, S.; Gu, L.; Liu, Y. H.; Bai, H. Y.; Wang, W. H.

    2017-09-01

    Searching strain sensitive materials for electronic skin is of crucial significance because of the restrictions of current materials such as poor electrical conductivity, large energy consumption, complex manufacturing process, and high cost. Here, we report a flexible strain sensor based on the Zr55Cu30Ni5Al10 metallic glass thin film which we name metallic glass skin. The metallic glass skin, synthesized by ion beam deposition, exhibits piezoresistance effects with a gauge factor of around 2.86, a large detectable strain range (˜1% or 180° bending angle), and good conductivity. Compared to other e-skin materials, the temperature coefficient of resistance of the metallic glass skin is extremely low (9.04 × 10-6 K-1), which is essential for the reduction in thermal drift. In addition, the metallic glass skin exhibits distinct antibacterial behavior desired for medical applications, also excellent reproducibility and repeatability (over 1000 times), nearly perfect linearity, low manufacturing cost, and negligible energy consumption, all of which are required for electronic skin for practical applications.

  9. Flexibility in metal-organic framework materials: Impact on sorption properties

    NASA Astrophysics Data System (ADS)

    Fletcher, Ashleigh J.; Thomas, K. Mark; Rosseinsky, Matthew J.

    2005-08-01

    Recent years have seen the development of a new class of porous coordination polymers known collectively as metal organic framework materials (MOFs). This review outlines recent progress in understanding how adsorption characteristics of these systems differ from rigid classical sorbents such as activated carbon and zeolites. Gas/vapor adsorption studies for characterization of the porous structures of MOF materials are reviewed and differences in adsorption characteristics based on detailed measurement of equilibrium and dynamical sorption behavior, compared with previous generations of sorbents, are highlighted. The role of framework flexibility and specific structural features, such as windows and pore cavities, within the MOF porous structures are discussed in relation to adsorption mechanisms.

  10. Comparison of outcomes among secondary covered metallic, uncovered metallic, and plastic biliary stents in treating occluded primary metallic stents in malignant distal biliary obstruction.

    PubMed

    Cho, Jae Hee; Jeon, Tae Joo; Park, Jeong Youp; Kim, Hee Man; Kim, Yoon Jae; Park, Seung Woo; Chung, Jae Bock; Song, Si Young; Bang, Seungmin

    2011-02-01

    The self-expandable metallic stent (SEMS) has been widely used for unresectable malignant biliary obstruction but eventually becomes occluded by tumor ingrowth/overgrowth and sludge. Therefore, we aimed to determine the therapeutic effectiveness of secondary stents and to find differences according to various combinations of the first and second stents for the management of occluded SEMSs in patients with malignant distal biliary obstruction. Between 1999 and November 2008, 77 patients with malignant biliary obstruction underwent secondary biliary stent placement as "stent-in-stent" at three university hospitals in Korea (40 covered, 26 uncovered, and 11 plastic stents). The membrane of the covered SEMS was regarded as the barrier against tumor ingrowth. We categorized the patients into three groups based on whether the covered SEMS was either the first or the second stent: membrane-SEMS (18 covered-covered; 9 covered-uncovered; 22 uncovered-covered SEMS), bare-SEMS (17 uncovered-uncovered SEMS), and plastic stent (3 covered-plastic; 8 uncovered-plastic). The median patency of second stents was 138, 109, and 88 days (covered, uncovered, and plastic stents). The second covered SEMSs had a significantly longer patency than plastic stents (p=0.047). In a multivariate analysis including membrane-SEMS, bare-SEMS, and plastic stent groups, the bare-SEMS had a worse cumulative stent patency (HR=2.04, CI=1.08-3.86) and survival time (HR=2.37, CI=1.25-4.49) than the membrane-SEMS. Patients with ampulla of Vater cancer had better stent patency (HR=0.27, CI=0.08-0.98) and survival (HR=0.17, CI=0.04-0.77) than those with other pancreatobiliary malignancies. In addition, antitumor treatment prolonged survival time (HR=0.50, CI=0.26-0.99). The placement of additional biliary stents using the "stent-in-stent" method is an effective treatment for an occluded metallic primary stent. In addition, double biliary SEMS placement using at least one covered SEMS (in the primary and

  11. Covered self-expandable metal stents for benign biliary tract diseases.

    PubMed

    Baron, Todd H

    2011-05-01

    Benign biliary diseases are often managed endoscopically using plastic stents. Benign biliary strictures (BBS) respond to placement of multiple large-bore plastic stents, though requiring multiple procedures to place stents, and to exchange stents to prevent and/or treat stent occlusion. Bile leaks close using plastic stents, which divert bile away from the leak into the duodenum. Covered self-expandable metal stents (CSEMS), intended for palliation of malignant biliary obstruction, have been used to treat benign biliary diseases. Advantages include small predeployment and large postexpansion diameters. Lack of imbedding of the metal into the bile duct wall enables removability. For strictures, one CSEMS is inserted without need for dilation and remains in place for up to 6 months. Successful removal has been reported in all cases. Long-term stricture resolution is achieved in up to 92%. Adverse events include migration and new stricture formation. For treatment of complex bile leaks, the covering and large diameter allow successful closure in nearly all cases. Other uses of CSEMS include treatment of postsphincterotomy bleeding and closure of perforations. CSEMS show promise for treatment of BBS and complex biliary leaks. Successful resolution can be achieved in the majority of patients with the advantage of fewer procedures, which offsets their higher cost.

  12. Interplay between defects, disorder and flexibility in metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Bennett, Thomas D.; Cheetham, Anthony K.; Fuchs, Alain H.; Coudert, François-Xavier

    2017-01-01

    Metal-organic frameworks are a novel family of chemically diverse materials, which are of interest across engineering, physics, chemistry, biology and medicine-based disciplines. Since the development of the field in its current form more than two decades ago, priority has been placed on the synthesis of new structures. However, more recently, a clear trend has emerged in shifting the emphasis from material design to exploring the chemical and physical properties of structures already known. In particular, although such nanoporous materials were traditionally seen as rigid crystalline structures, there is growing evidence that large-scale flexibility, the presence of defects and long-range disorder are not the exception in metal-organic frameworks, but the rule. Here we offer some perspective into how these concepts are perhaps inescapably intertwined, highlight recent advances in our understanding and discuss how a consideration of the interfaces between them may lead to enhancements of the materials' functionalities.

  13. Graphene as a flexible template for controlling magnetic interactions between metal atoms.

    PubMed

    Lee, Sungwoo; Kim, Dongwook; Robertson, Alex W; Yoon, Euijoon; Hong, Suklyun; Ihm, Jisoon; Yu, Jaejun; Warner, Jamie H; Lee, Gun-Do

    2017-03-01

    Metal-doped graphene produces magnetic moments that have potential application in spintronics. Here we use density function theory computational methods to show how the magnetic interaction between metal atoms doped in graphene can be controlled by the degree of flexure in a graphene membrane. Bending graphene by flexing causes the distance between two substitutional Fe atoms covalently bonded in graphene to gradually increase and these results in the magnetic moment disappearing at a critical strain value. At the critical strain, a carbon atom can enter between the two Fe atoms and blocks the interaction between relevant orbitals of Fe atoms to quench the magnetic moment. The control of interactions between doped atoms by exploiting the mechanical flexibility of graphene is a unique approach to manipulating the magnetic properties and opens up new opportunities for mechanical-magnetic 2D device systems.

  14. Graphene as a flexible template for controlling magnetic interactions between metal atoms

    NASA Astrophysics Data System (ADS)

    Lee, Sungwoo; Kim, Dongwook; Robertson, Alex W.; Yoon, Euijoon; Hong, Suklyun; Ihm, Jisoon; Yu, Jaejun; Warner, Jamie H.; Lee, Gun-Do

    2017-03-01

    Metal-doped graphene produces magnetic moments that have potential application in spintronics. Here we use density function theory computational methods to show how the magnetic interaction between metal atoms doped in graphene can be controlled by the degree of flexure in a graphene membrane. Bending graphene by flexing causes the distance between two substitutional Fe atoms covalently bonded in graphene to gradually increase and these results in the magnetic moment disappearing at a critical strain value. At the critical strain, a carbon atom can enter between the two Fe atoms and blocks the interaction between relevant orbitals of Fe atoms to quench the magnetic moment. The control of interactions between doped atoms by exploiting the mechanical flexibility of graphene is a unique approach to manipulating the magnetic properties and opens up new opportunities for mechanical-magnetic 2D device systems.

  15. Improving heat transfer with pool boiling by covering of heating surface with metallic spheres

    SciTech Connect

    Matijevic, M.; Djuric, M.; Zavargo, Z.; Novakovic, M. )

    1992-01-01

    In this paper, boiling heat transfer (BHT) is investigated experimentally. Smooth copper walls were covered with single sphere layer and corresponding temperature difference and heat flux were measured. The results were compared with published data for several types of heating surfaces. Comparative analysis shows that surfaces covered with spheres have characteristics as good as the other systems, if not better. There are many ways to enhance boiling heat transfer. One of them is to cover the heating surface with a layer of solid particles, which either remain on the surface during the process or circulate through the boiling liquid, generating a porous two-component, three-phase system. Particles are made of various materials (glass, alumosilicate, corundum, sand, mullite some metals, etc.), which are shaped as spheres mostly, but sometimes are irregular bodies. Many different parameters were proposed to characterize the porous layer. The influence of particles can be expressed by introducing the effective thermal-physical properties of a complex medium. Also, if the working regime can be described as any kind of fluidization, then all quantities developed to be applied to this matter can be used in the case of heat fluidization.

  16. A high-performance, flexible and robust metal nanotrough-embedded transparent conducting film for wearable touch screen panels

    NASA Astrophysics Data System (ADS)

    Im, Hyeon-Gyun; An, Byeong Wan; Jin, Jungho; Jang, Junho; Park, Young-Geun; Park, Jang-Ung; Bae, Byeong-Soo

    2016-02-01

    We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer). The monolithic composite structure of our transparent conducting film allows simultaneously high thermal stability (24 h at 250 °C in air), a smooth surface topography (Rrms < 1 nm) and excellent opto-electrical properties. A flexible touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband.We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer). The monolithic composite structure of our transparent conducting film allows simultaneously high thermal stability (24 h at 250 °C in air), a smooth surface topography (Rrms < 1 nm) and excellent opto-electrical properties. A flexible touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07657a

  17. Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

    SciTech Connect

    Kim, Charles Y. Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P.

    2012-08-15

    Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

  18. Metallization and biopatterning on ultra-flexible substrates via dextran sacrificial layers.

    PubMed

    Tseng, Peter; Pushkarsky, Ivan; Di Carlo, Dino

    2014-01-01

    Micro-patterning tools adopted from the semiconductor industry have mostly been optimized to pattern features onto rigid silicon and glass substrates, however, recently the need to pattern on soft substrates has been identified in simulating cellular environments or developing flexible biosensors. We present a simple method of introducing a variety of patterned materials and structures into ultra-flexible polydimethylsiloxane (PDMS) layers (elastic moduli down to 3 kPa) utilizing water-soluble dextran sacrificial thin films. Dextran films provided a stable template for photolithography, metal deposition, particle adsorption, and protein stamping. These materials and structures (including dextran itself) were then readily transferrable to an elastomer surface following PDMS (10 to 70∶1 base to crosslinker ratios) curing over the patterned dextran layer and after sacrificial etch of the dextran in water. We demonstrate that this simple and straightforward approach can controllably manipulate surface wetting and protein adsorption characteristics of PDMS, covalently link protein patterns for stable cell patterning, generate composite structures of epoxy or particles for study of cell mechanical response, and stably integrate certain metals with use of vinyl molecular adhesives. This method is compatible over the complete moduli range of PDMS, and potentially generalizable over a host of additional micro- and nano-structures and materials.

  19. Metallization and Biopatterning on Ultra-Flexible Substrates via Dextran Sacrificial Layers

    PubMed Central

    Tseng, Peter; Pushkarsky, Ivan; Di Carlo, Dino

    2014-01-01

    Micro-patterning tools adopted from the semiconductor industry have mostly been optimized to pattern features onto rigid silicon and glass substrates, however, recently the need to pattern on soft substrates has been identified in simulating cellular environments or developing flexible biosensors. We present a simple method of introducing a variety of patterned materials and structures into ultra-flexible polydimethylsiloxane (PDMS) layers (elastic moduli down to 3 kPa) utilizing water-soluble dextran sacrificial thin films. Dextran films provided a stable template for photolithography, metal deposition, particle adsorption, and protein stamping. These materials and structures (including dextran itself) were then readily transferrable to an elastomer surface following PDMS (10 to 70∶1 base to crosslinker ratios) curing over the patterned dextran layer and after sacrificial etch of the dextran in water. We demonstrate that this simple and straightforward approach can controllably manipulate surface wetting and protein adsorption characteristics of PDMS, covalently link protein patterns for stable cell patterning, generate composite structures of epoxy or particles for study of cell mechanical response, and stably integrate certain metals with use of vinyl molecular adhesives. This method is compatible over the complete moduli range of PDMS, and potentially generalizable over a host of additional micro- and nano-structures and materials. PMID:25153326

  20. Flexible transparent metal/polymer composite materials based on optical resonant laminate structures.

    PubMed

    Narayanan, Sudarshan; Choi, Jihoon; Porter, Lisa; Bockstaller, Michael R

    2013-05-22

    Suitable design of periodic metal/polymer composite materials is shown to facilitate resonant tunneling of light at absorbing wavelengths and to provide a means to significantly reduce optical absorption losses in polymer-based metallodielectric composite structures. The conditions for resonant tunneling are established based on the concept of "photonic band edge alignment" in 1D-periodic systems. For the particular case of a four-layer gold/polystyrene laminate structure, it is shown that the matching of the lower band edge of the 1D-periodic structure with the plasma frequency of the metal component facilitates the increase of optical transmission by about 500% as compared to monolithic film structures of equal total thickness. The effect of sheet thickness on the optical properties of thin metal films is determined and shown to be an important prerequisite for the reliable prediction of resonant metallodielectric structures. The resonant 1D-periodic metal/polymer heterostructures are shown to retain the flexural stability of the polymer matrix and thus could find application as flexible transparent conductors in areas such as "plastic electronics".

  1. High-Performance Flexible Transparent Electrode with an Embedded Metal Mesh Fabricated by Cost-Effective Solution Process.

    PubMed

    Khan, Arshad; Lee, Sangeon; Jang, Taehee; Xiong, Ze; Zhang, Cuiping; Tang, Jinyao; Guo, L Jay; Li, Wen-Di

    2016-06-01

    A new structure of flexible transparent electrodes is reported, featuring a metal mesh fully embedded and mechanically anchored in a flexible substrate, and a cost-effective solution-based fabrication strategy for this new transparent electrode. The embedded nature of the metal-mesh electrodes provides a series of advantages, including surface smoothness that is crucial for device fabrication, mechanical stability under high bending stress, strong adhesion to the substrate with excellent flexibility, and favorable resistance against moisture, oxygen, and chemicals. The novel fabrication process replaces vacuum-based metal deposition with an electrodeposition process and is potentially suitable for high-throughput, large-volume, and low-cost production. In particular, this strategy enables fabrication of a high-aspect-ratio (thickness to linewidth) metal mesh, substantially improving conductivity without considerably sacrificing transparency. Various prototype flexible transparent electrodes are demonstrated with transmittance higher than 90% and sheet resistance below 1 ohm sq(-1) , as well as extremely high figures of merit up to 1.5 × 10(4) , which are among the highest reported values in recent studies. Finally using our embedded metal-mesh electrode, a flexible transparent thin-film heater is demonstrated with a low power density requirement, rapid response time, and a low operating voltage.

  2. Difficult removal of fully covered self expandable metal stents (SEMS) for benign biliary strictures: the "SEMS in SEMS" technique.

    PubMed

    Tringali, Andrea; Blero, Daniel; Boškoski, Ivo; Familiari, Pietro; Perri, Vincenzo; Devière, Jacques; Costamagna, Guido

    2014-06-01

    Removal of biliary Fully Covered Self Expandable Metal Stents can fail due to stent migration and/or hyperplastic ingrowth/overgrowth. A case series of 5 patients with benign biliary strictures (2 post-cholecystectomy, 2 following liver transplantation and 1 related to chronic pancreatitis) is reported. The biliary stricture was treated by temporary insertion of Fully Covered Self Expandable Metal Stents. Stent removal failed due to proximal stent migration and/or overgrowth. Metal stent removal was attempted a few weeks after the insertion of another Fully Covered Metal Stent into the first one. The inner Fully Covered Self Expandable Metal Stent compressed the hyperplastic tissue, leading to the extraction of both the stents in all cases. Two complications were reported as a result of the attempt to stents removal (mild pancreatitis and self-limited haemobilia). In the present series, the "SEMS in SEMS" technique revealed to be effective when difficulties are encountered during Fully Covered Self Expandable Metal Stents removal. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  3. Impact of grass cover on the magnetic susceptibility measurements for assessing metal contamination in urban topsoil.

    PubMed

    Golden, Nessa; Zhang, Chaosheng; Potito, Aaron P; Gibson, Paul J; Bargary, Norma; Morrison, Liam

    2017-03-02

    In recent decades, magnetic susceptibility monitoring has developed as a useful technique in environmental pollution studies, particularly metal contamination of soil. This study provides the first ever examination of the effects of grass cover on magnetic susceptibility (MS) measurements of underlying urban soils. Magnetic measurements were taken in situ to determine the effects on κ (volume magnetic susceptibility) when the grass layer was present (κ(grass)) and after the grass layer was trimmed down to the root (κ(no grass)). Height of grass was recorded in situ at each grid point. Soil samples (n=185) were collected and measurements of mass specific magnetic susceptibility (χ) were performed in the laboratory and frequency dependence (χfd%) calculated. Metal concentrations (Pb, Cu, Zn and Fe) in the soil samples were determined and a gradiometry survey carried out in situ on a section of the study area. Significant correlations were found between each of the MS measurements and the metal content of the soil at the p<0.01 level. Spatial distribution maps were created using Inverse Distance Weighting (IDW) and Local Indicators of Spatial Association (LISA) to identify common patterns. κ(grass) (ranged from 1.67 to 301.00×10(-5) SI) and κ(no grass) (ranged from 2.08 to 530.67×10(-5) SI) measured in situ are highly correlated [r=0.966, n=194, p<0.01]. The volume susceptibility datasets in the presence and absence of grass coverage share a similar spatial distribution pattern. This study re-evaluates in situ κ monitoring techniques and the results suggest that the removal of grass coverage prior to obtaining in situ κ measurements of urban soil is unnecessary. This layer does not impede the MS sensor from accurately measuring elevated κ in soils, and therefore κ measurements recorded with grass coverage present can be reliably used to identify areas of urban soil metal contamination.

  4. Coupling into and scattering from cylindrical structures covered periodically with metallic patches

    NASA Technical Reports Server (NTRS)

    Cwik, Tom

    1990-01-01

    Circular cylindrical structures covered periodically with metallic patches are considered. After an analogy to planar periodic surfaces is shown, formulations are presented for calculating induced currents on the curved surface. The equations are solved and results calculated for the specific case of periodic strips on the cylindrical surface. For a cylindrical structure a two-dimensional periodicity exists, as in a planar structure, while a spherical structure allows only a rotational periodicity. When the cylindrical structure is excited by the characteristic harmonic of the system, the spectral response of the transmitted field exhibits resonances that depend on the surface periodicity, as is known for planar structures. Since the cylindrical structure contains finite closed regions, the effects of resonances internal to the structure are seen and give additional information as compared to planar structures.

  5. Benign and malignant esophageal strictures: treatment with a polyurethane-covered retrievable expandable metallic stent.

    PubMed

    Song, H Y; Park, S I; Jung, H Y; Kim, S B; Kim, J H; Huh, S J; Kim, T H; Kim, Y K; Park, S; Yoon, H K; Sung, K B; Min, Y I

    1997-06-01

    To evaluate the clinical effectiveness of a polyurethane-covered, retrievable, self-expandable metallic stent and hook catheter in the treatment of esophageal strictures. Stents were constructed of 0.4-mm stainless steel wire in a cylindric zig-zag configuration of six to nine bends. Four to eight stents were connected in tandem by dipping in a polyurethane solution. A nylon loop was hooked inside to each bend of the proximal portion of the stent and strung with a thread. Under fluoroscopic guidance, 22 stents were placed in 16 patients with a malignant stricture and five patients with a benign stricture. The stent was removed with a hook catheter 2 months after placement in patients with a benign stricture and when complications occurred in patients with a malignant stricture. All patients had dysphagia with ingestion of soft foods or liquids. Stent placement was technically successful and well tolerated in 20 patients. In one patient, the stent was misplaced but relocated successfully. After stent placement, all patients were able to ingest solid and/or soft foods without dysphagia. After stent removal, strictures showed improvement but recurred in two patients. Use of polyurethane-covered, retrievable expandable stents seems to be a feasible and effective method of treatment of benign and malignant esophageal strictures.

  6. Photoreactive and Metal-Platable Copolymer Inks for High-Throughput, Room-Temperature Printing of Flexible Metal Electrodes for Thin-Film Electronics.

    PubMed

    Yu, You; Xiao, Xiang; Zhang, Yaokang; Li, Kan; Yan, Casey; Wei, Xiaoling; Chen, Lina; Zhen, Hongyu; Zhou, Hang; Zhang, Shengdong; Zheng, Zijian

    2016-06-01

    Photoreactive and metal-platable copolymer inks are reported for the first time to allow high-throughput printing of high-performance flexible electrodes at room temperature. This new copolymer ink accommodates various types of printing technologies, such as soft lithography molding, screen printing, and inkjet printing. Electronic devices including resistors, sensors, solar cells, and thin-film transistors fabricated with these printed electrodes show excellent electrical performance and mechanical flexibility.

  7. Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

    NASA Astrophysics Data System (ADS)

    Kranz, Lukas; Gretener, Christina; Perrenoud, Julian; Schmitt, Rafael; Pianezzi, Fabian; La Mattina, Fabio; Blösch, Patrick; Cheah, Erik; Chirilă, Adrian; Fella, Carolin M.; Hagendorfer, Harald; Jäger, Timo; Nishiwaki, Shiro; Uhl, Alexander R.; Buecheler, Stephan; Tiwari, Ayodhya N.

    2013-08-01

    Roll-to-roll manufacturing of CdTe solar cells on flexible metal foil substrates is one of the most attractive options for low-cost photovoltaic module production. However, various efforts to grow CdTe solar cells on metal foil have resulted in low efficiencies. This is caused by the fact that the conventional device structure must be inverted, which imposes severe restrictions on device processing and consequently limits the electronic quality of the CdTe layer. Here we introduce an innovative concept for the controlled doping of the CdTe layer in the inverted device structure by means of evaporation of sub-monolayer amounts of Cu and subsequent annealing, which enables breakthrough efficiencies up to 13.6%. For the first time, CdTe solar cells on metal foil exceed the 10% efficiency threshold for industrialization. The controlled doping of CdTe with Cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Our results offer new research directions for solving persistent challenges of CdTe photovoltaics.

  8. Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil.

    PubMed

    Kranz, Lukas; Gretener, Christina; Perrenoud, Julian; Schmitt, Rafael; Pianezzi, Fabian; La Mattina, Fabio; Blösch, Patrick; Cheah, Erik; Chirilă, Adrian; Fella, Carolin M; Hagendorfer, Harald; Jäger, Timo; Nishiwaki, Shiro; Uhl, Alexander R; Buecheler, Stephan; Tiwari, Ayodhya N

    2013-01-01

    Roll-to-roll manufacturing of CdTe solar cells on flexible metal foil substrates is one of the most attractive options for low-cost photovoltaic module production. However, various efforts to grow CdTe solar cells on metal foil have resulted in low efficiencies. This is caused by the fact that the conventional device structure must be inverted, which imposes severe restrictions on device processing and consequently limits the electronic quality of the CdTe layer. Here we introduce an innovative concept for the controlled doping of the CdTe layer in the inverted device structure by means of evaporation of sub-monolayer amounts of Cu and subsequent annealing, which enables breakthrough efficiencies up to 13.6%. For the first time, CdTe solar cells on metal foil exceed the 10% efficiency threshold for industrialization. The controlled doping of CdTe with Cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Our results offer new research directions for solving persistent challenges of CdTe photovoltaics.

  9. Enabling Overall Water Splitting on Photocatalysts by CO-Covered Noble Metal Co-catalysts

    SciTech Connect

    Berto, Tobias F.; Sanwald, Kai E.; Byers, J. Paige; Browning, Nigel D.; Gutiérrez, Oliver Y.; Lercher, Johannes A.

    2016-10-17

    Photocatalytic overall water splitting requires co-catalysts that efficiently promote the generation of H-2 but do not catalyze its reverse oxidation. We demonstrate that CO chemisorbed on metal co-catalysts (Rh, Pt, Pd) suppresses the back reaction while maintaining the rate of H-2 evolution. On Rh/GaN:ZnO, the highest H-2 production rates were obtained with 4-40 mbar of CO, the back reaction remaining suppressed below 7 mbar of O-2. The O-2 and H-2 evolution rates compete with CO oxidation and the back reaction. The rates of all reactions increased with increasing photon absorption. However, due to different dependencies on the rate of charge carrier generation, the selectivities for O-2 and H-2 formation increased in comparison to CO oxidation and the back reaction with increasing photon flux and/or quantum efficiency. Under optimum conditions, the impact of CO to prevent the back reaction is identical to that of a Cr2O3 layer covering the active metal particle.

  10. Use of fully covered self-expanding metal stents in benign biliary diseases

    PubMed Central

    García-Cano, Jesús

    2012-01-01

    Biliary fully covered self-expanding metal stents (FCSEMS) are now being used to treat several benign biliary conditions. Advantages include small predeployment and large postexpansion diameters in addition to an easy insertion technique. Lack of imbedding of the metal into the bile duct wall enables removability. In benign biliary strictures that usually require multiple procedures, despite the substantially higher cost of FCSEMS compared with plastic stents, the use of FCSEMS is offset by the reduced number of endoscopic retrograde cholangiopancreatography interventions required to achieve stricture resolution. In the same way, FCSEMS have also been employed to treat complex bile leaks, perforation and bleeding after endoscopic biliary sphincterotomy and as an aid to maintain permanent drainage tracts obtained by means of Endoscopic Ultrasound-guided biliary drainage. Good success rates have been achieved in all these conditions with an acceptable number of complications. FCSEMS were successfully removed in all patients. Comparative studies of FCSEMS and plastic stents are needed to demonstrate efficacy and cost-effectiveness PMID:22523615

  11. Influence of the vegetative cover on the fate of trace metals in retention systems simulating roadside infiltration swales.

    PubMed

    Leroy, M C; Marcotte, S; Legras, M; Moncond'huy, V; Le Derf, F; Portet-Koltalo, F

    2017-02-15

    Large-scale outdoor mesocosms were designed and co-contaminated with metals (Cd, Pb, Zn) and organic compounds to better understand the complex functioning of urban roadside swale environments. Infiltration systems were planted with macrophytes (P. arundinaceae, J. effusus and I. pseudacorus) or grassed, and natural or spiked target metals were monitored over two years. In the non-spiked mesocosms, atmospheric metal inputs were slightly higher than outputs, leading to low metal accumulation in topsoils and to very low outflow water contamination (<0.7% of the initial metal stock). In the spiked infiltration systems that simulated point pollution through water inflow, transfer of the initial stock of metals to the deeper soil layers was quite low and outflow water contamination was very low (<0.6% of the initial stock). The main metal output from these systems occurred in the first days of their installation because of the high metal solubility in water and insufficient plant cover at that time. The infiltration systems stabilized after a few weeks, probably because of stronger sorption to soil aggregates, and because of plant root development. Mephytoextraction in plant roots was more efficient in mesocosms planted with P. arundinacea and grass. Metal phytoextraction in plant aerial parts was also better for grass and P. arundinacea, when considering metal standing stocks instead of their concentration in plants. J. effusus was a good metal accumulator, but its low aboveground biomass development was less favorable to metal removal through harvesting.

  12. Thickness dependent fatigue life at microcrack nucleation for metal thin films on flexible substrates

    NASA Astrophysics Data System (ADS)

    Sun, X. J.; Wang, C. C.; Zhang, J.; Liu, G.; Zhang, G. J.; Ding, X. D.; Zhang, G. P.; Sun, J.

    2008-10-01

    For polymer-supported metal thin films used in flexible electronics, the definition of the fatigue lifetime at microcrack nucleation (FLMN) should be more physically meaningful than all the previous definitions at structural instability. In this paper, the FLMN of Cu films (with thickness from 100 nm to 3.75 µm) as well as Al thin films (from 80 to 800 nm) was experimentally characterized at different strain ranges and different thicknesses by using a simple electrical resistance measurement (ERM). A significant thickness dependence was revealed for the FLMN and a similar Coffin-Manson fatigue relationship observed commonly in bulk materials was found to be still operative in both the films. Microstructural analyses were carried out to verify the feasibility of ERM correspondingly.

  13. Flexible Organic Phototransistor Array with Enhanced Responsivity via Metal-Ligand Charge Transfer.

    PubMed

    Liu, Xien; Lee, Eun Kwang; Kim, Dong Yeong; Yu, Hojeong; Oh, Joon Hak

    2016-03-23

    Phototransistors based on organic photoactive materials combine tunable light absorption in the spectral region from ultraviolet to near-infrared with low-temperature processability over large areas on flexible substrates. However, they often exhibit low photoresponsivity because of low molar extinction coefficient of photoactive components. We report a simple, yet highly efficient solution method for enhancing the performance of organic phototransistors using ruthenium complex 1 (Ru-complex 1). An air-stable n-type organic semiconductor, N,N'-bis(2-phenylethyl)-perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI), has been deposited on a silicon wafer and a transparent polyimide (PI) substrate via thermal evaporation under vacuum. The BPE-PTCDI phototransistors functionalized with Ru-complex 1 exhibit ∼5000 times higher external quantum efficiency (EQE) than that of pristine BPE-PTCDI phototransistors, owing to the metal-ligand charge transfer (MLCT) from Ru-complex 1 to the active component of the device. In addition, a large 10 × 10 phototransistor array (2.5 × 2.5 cm(2)) has been prepared on a transparent PI substrate, showing distinct light mapping. The fabricated phototransistor array is highly flexible and twistable and works well under tensile and compressive strains. We believe that our simple method will pave a viable way for improvements in the photoresponsivity of organic semiconductors for applications in wearable organic optoelectronic devices.

  14. The linkage between ribosomal crystallography, metal ions, heteropolytungstates and functional flexibility

    NASA Astrophysics Data System (ADS)

    Bashan, Anat; Yonath, Ada

    2008-11-01

    Crystallography of ribosomes, the universal cell nucleoprotein assemblies facilitating the translation of the genetic-code into proteins, met with severe problems owing to the large size, complex structure, inherent flexibility and high conformational variability of the ribosome. For the case of the small ribosomal subunit, which caused extreme difficulties, post-crystallization treatment by minute amounts of a heteropolytungstate cluster allowed structure determination at atomic resolution. This cluster played a dual role: providing anomalous phasing power and dramatically increased the resolution, by stabilization of a selected functional conformation. Thus, four out of the fourteen clusters that bind to each of the crystallized small subunits are attached to a specific ribosomal protein in a fashion that may control a significant component of the subunit internal flexibility, by "gluing" symmetrical related subunits. Here, we highlight basic issues in the relationship between metal ions and macromolecules and present common traits controlling in the interactions between polymetalates and various macromolecules, which may be extended towards the exploitation of polymetalates for therapeutical treatment.

  15. Shift and elimination of microwave Fabry-Perot resonances in a dielectric covered with a thin metal layer

    NASA Astrophysics Data System (ADS)

    Ragulis, Paulius; Simniškis, Rimantas; Kancleris, Žilvinas

    2015-04-01

    In this paper, we consider a plane electromagnetic wave incident onto a dielectric plate, which has one surface covered with a thin layer of metal. An oblique incident angle was considered for the TE (s polarization in optic) and TM (p polarization) plane waves. The thin metal layer is treated as an infinitesimal thickness. It was characterized by a surface conductivity and accounted for by a tangential magnetic field component step induced by the current flow in the metal layer. Compact expressions, which describe the reflection, transmission and absorption in a dielectric plate covered with a thin layer of metal, have been obtained. It was shown that by choosing the appropriate surface conductivity, the Fabry-Perot transmission resonances can be shifted to the position where the maximum reflection is observed in the case of an uncovered dielectric. On the other hand, the elimination of the Fabry-Perot resonances can be also achieved by choosing a proper metal surface conductivity. Measurements of the reflection from the glass covered with a thin layer of metal have been performed in a wide microwave frequency range (2-12 GHz) revealing a large difference in the measured reflection coefficient from the dielectric and metalized surfaces. The measured results fit well with those calculated by employing analytical expressions obtained in this paper.

  16. Widely applicable coinage metal window electrodes on flexible polyester substrates applied to organic photovoltaics.

    PubMed

    Stec, Helena M; Hatton, Ross A

    2012-11-01

    The fabrication, exceptional properties, and application of 8 nm thick Cu, Ag, Au, and Cu/Ag bilayer electrodes on flexible polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) substrates is reported. These electrodes are fabricated using a solvent free process in which the plastic surface is chemically modified with a molecular monolayer of thiol and amine terminated alkylsilanes prior to metal deposition. The resulting electrodes have a sheet resistance of ≤14 Ω sq⁻¹, are exceptionally robust and can be rapidly thermally annealed at 200 °C to reduce their sheet resistance to ≤9 Ω sq⁻¹. Notably, annealing Au electrodes briefly at 200 °C causes the surface to revert almost entirely to the {111} face, rendering it ideal as a model electrode for fundamental science and practical application alike. The power conversion efficiency of 1 cm² organic photovoltaics (OPVs) employing 8 nm Ag and Au films as the hole-extracting window electrode exhibit performance comparable to those on indium-tin oxide, with the advantage that they are resistant to repeated bending through a small radius of curvature and are chemically well-defined. OPVs employing Cu and bilayer Cu:Ag electrodes exhibit inferior performance due to a lower open-circuit voltage and fill factor. Measurements of the interfacial energetics made using the Kelvin probe technique provide insight into the physical reason for this difference. The results show how coinage metal electrodes offer a viable alternative to ITO on flexible substrates for OPVs and highlight the challenges associated with the use of Cu as an electrode material in this context.

  17. Assembly of new polyoxometalate-templated metal-organic frameworks based on flexible ligands

    NASA Astrophysics Data System (ADS)

    Li, Na; Mu, Bao; Lv, Lei; Huang, Rudan

    2015-03-01

    Four new polyoxometalate(POM)-templated metal-organic frameworks based on flexible ligands, namely, [Cu6(bip)12(PMoVI12O40)2(PMoVMoVI11O40O2)]·8H2O(1), [CuI3CuII3(bip)12(PMoVI12O40)2(PMoV12O34)]·8H2O(2), [Ni6(bip)12(PMoVI12O40)(PMoVI11MoVO40)2]Cl·6H2O(3), [CoII3CoIII2(H2bib)2(Hbib)2(PW9O34)2(H2O)6]·6H2O(4) (bip=1,3-bis(imidazolyl)propane, bib=1,4-bis(imidazolyl)butane) have been obtained under hydrothermal condition and characterized by single-crystal X-ray diffraction analyses, elemental analyses, and thermogravimetric (TG) analyses. The studies of single crystal X-ray indicate that compounds 1-3 crystallize in the trigonal space group P-3, and compound 4 crystallizes in the triclinic space group P-1. Compounds 1 and 3 represent 3D frameworks, and POMs as the guest molecules are incorporated into the cages which are composed of the ligands and metals, while compounds 2 and 4 show 3D frameworks by hydrogen bonds. This compounds provide new examples of host-guest compounds based on flexible bis(imidazole) ligands. In addition, the electrochemical property and the catalytic property of compound 1 have also been investigated.

  18. Laser Induced Forward Transfer of High Viscosity Silver Paste for New Metallization Methods in Photovoltaic and Flexible Electronics Industry

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Munoz-Martin, D.; Morales, M.; Molpeceres, C.; Sánchez-Cortezon, E.; Murillo-Gutierrez, J.

    Laser Induced Forward Transfer (LIFT) has been studied in the past as a promising approach for precise metallization in electronics using metallic inks and pastes. In this work we present large area metallization using LIFT of fully commercial silver-based pastes initially designed for solar cell screen-printing. We discuss the mechanisms for the material transfer both in ns and ps regimes of irradiation of these high viscosity materials, and the potential use of this technique in the photovoltaic industry (both in standard c-Si solar cells and thin film technologies) and flexible electronics devices. In particular we summarize the results of our group in this field, demonstrating that our approach is capable of improving the aspect ratio of the standard metallization patterns achieved with screen-printing technologies in those technological fields and, in addition, of fulfilling the requirements imposed by the mechanical properties of the substrates in flexible electronic applications.

  19. An Artificial Solid Electrolyte Interphase with High Li-Ion Conductivity, Mechanical Strength, and Flexibility for Stable Lithium Metal Anodes.

    PubMed

    Liu, Yayuan; Lin, Dingchang; Yuen, Pak Yan; Liu, Kai; Xie, Jin; Dauskardt, Reinhold H; Cui, Yi

    2017-03-01

    An artificial solid electrolyte interphase (SEI) is demonstrated for the efficient and safe operation of a lithium metal anode. Composed of lithium-ion-conducting inorganic nanoparticles within a flexible polymer binder matrix, the rationally designed artificial SEI not only mechanically suppresses lithium dendrite formation but also promotes homogeneous lithium-ion flux, significantly enhancing the efficiency and cycle life of the lithium metal anode.

  20. Use of fully covered self-expanding metal stents for the management of benign biliary conditions.

    PubMed

    García-Cano, J; Taberna-Arana, L; Jimeno-Ayllón, C; Martínez-Fernández, R; Serrano-Sánchez, L; Reyes-Guevara, A K; Viñuelas-Chicano, M; Gómez-Ruiz, C J; Morillas-Ariño, M J; Pérez-García, J I; Pérez-Vigara, G; Pérez-Sola, A

    2010-09-01

    biliary self-expanding metal stents (SEMS) have the advantage of being inserted undeployed with very small sizes and provide, when fully opened, large diameters for biliary drainage. However, their use in benign conditions has been very limited, mainly because of difficulty in their extraction. We present our initial experience with a fully covered SEMS (Wallflex) for the management of benign problems of the bile duct. in a prospective study, stents of 8 mm in diameter and 4, 6 or 8 cm long were inserted by means of ERCP. These SEMS were chosen when according to medical judgement it was thought that diameters greater than 10 French (3.3 mm) were needed for proper biliary drainage. Stents were extracted also endoscopically, several months later when deemed clinically appropriate. twenty biliary SEMS were inserted. Reasons for insertion were: large intrahepatic biliary fistula after hydatid cyst surgery (1), perforation of the papillary area following endoscopic sphincterotomy (2), coaxial insertion to achieve patency in obstructed uncovered stents inserted in benign conditions (3), benign strictures (7), multiple and large common bile duct stones that could not be extracted because of tapering and stricturing of the distal common bile duct (7). In all cases, successful biliary drainage was achieved and there were no complications from insertion. Stents were easily extracted after a mean time of 132 days (36-270) in place. Complete resolution of biliary problems was obtained in 14 patients (70%). in our initial experience, the fully covered Wallflex biliary stent was removed without any complication after being in place in the common bile duct for a mean time of over four months. Therefore, it could be used in the management of benign biliary conditions.

  1. Self-assembly of flexible one-dimensional coordination polymers on metal surfaces.

    PubMed

    Heim, Daniel; Ecija, David; Seufert, Knud; Auwärter, Willi; Aurisicchio, Claudia; Fabbro, Chiara; Bonifazi, Davide; Barth, Johannes V

    2010-05-19

    We employed a de novo synthesized porphyrin module to construct one-dimensional (1D) Cu-coordinated polymers on Cu(111) and Ag(111) surfaces. The programmed geometry and functionality of the molecular module together with its conformational flexibility and substrate interaction yields sinuous metal-organic polymeric assemblies, based on an unusual two-fold Cu-pyridyl coordination motif. An analysis of scanning tunneling microscopy (STM) data reveals the occurrence of two enantiomers, resulting from the surface confinement that deconvolutes the module in 2D-chiral conformational isomers. The stereoisomers exhibit site-specific surface anchoring, from whence three discrete orientations are possible for each species. Their sequence and mutual arrangement determine direction and curvature of the metal-organic chains. The Cu-coordinated polymers are very similar on both Cu(111) and Ag(111), where their formation is induced by intrinsic and coevaporated adatoms, respectively, which indicates that the lateral bonding motif is predominantly independent of the substrate. In addition, molecular manipulation experiments show the collective motion of entire segments of the Cu-coordinated multi-porphyrin polymers.

  2. Metal ions and flexibility in a viral RNA pseudoknot at atomic resolution

    SciTech Connect

    Egli, Martin; Minasov, George; Su, Li; Rich, Alexander

    2010-03-05

    Many pathogenic viruses use programmed -1 ribosomal frameshifting to regulate translation of their structural and enzymatic proteins from polycistronic mRNAs. Frameshifting is commonly stimulated by a pseudoknot located downstream from a slippery sequence, the latter positioned at the ribosomal A and P sites. We report here the structures of two crystal forms of the frameshifting RNA pseudoknot from beet western yellow virus at resolutions of 1.25 and 2.85 {angstrom}. Because of the very high resolution of 1.25 {angstrom}, ten mono- and divalent metal ions per asymmetric unit could be identified, giving insight into potential roles of metal ions in stabilizing the pseudoknot. A magnesium ion located at the junction of the two pseudoknot stems appears to play a crucial role in stabilizing the structure. Because the two crystal forms exhibit mostly unrelated packing interactions and local crystallographic disorder in the high-resolution form was resolvable, the two structures offer the most detailed view yet of the conformational preference and flexibility of an RNA pseudoknot.

  3. 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.

  4. Molecular modeling of zinc paddlewheel molecular complexes and the pores of a flexible metal organic framework.

    PubMed

    Alzahrani, Khalid A H; Deeth, Robert J

    2016-04-01

    A new all-atom first-principles force field (FF) is constructed for the bimetallic, four-bladed zinc paddlewheel (ZPW) motif. Zinc-ligand interactions are described via Morse functions and the angular geometry at the metal centers is modeled with a pure ligand-ligand repulsion term. The ZPW-FF is principally based on 15 DFT-optimized model systems of general formula ZnPR.nL, where ZnP is the base Zn2(O2CR)4 unit, R = H, CH3 or CF3, L = NH3 or pyridine, and n = 0, 1 or 2. It correctly generates the distorted tetrahedral coordination of the uncapped [Zn2(O2CR)4] species in their ground states as well as giving reasonable structures and energies for the higher symmetry D4h transition state conformations. The zinc-ligand Morse function reference distance, r 0 , is further refined against 30 complexes located in the Cambridge Structural Database and this FF is applied to pore models of the flexible metal-organic framework (MOF) [Zn(bdc)2(dabco)]n (bdc = 1,4-benzendicarboxylate; dabco = 1,4-diazabicyclo(2.2.2)octane). A single pore model reproduces the unit cell of the evacuated MOF system while a 3×3 grid model is necessary to provide good agreement with the observed pronounced structural changes upon adsorption of either dimethylformamide or benzene.

  5. Flexible Metallic Overwrap Concept Developed for On-Orbit Repair of Space Shuttle Orbiter Leading Edges

    NASA Technical Reports Server (NTRS)

    Ritzert, Frank J.; Nesbitt, James A.

    2005-01-01

    The Columbia accident has focused attention on the critical need for on-orbit repair concepts for leading edges in the event that damage is incurred during space shuttle orbiter flight. Damage that is considered as potentially catastrophic for orbiter leading edges ranges from simple cracks to holes as large as 16 in. in diameter. NASA is particularly interested in examining potential solutions for areas of larger damage since such a problem was identified as the cause for the Columbia disaster. One possible idea for the on-orbit repair of the reinforced carbon/carbon (RCC) leading edges is an overwrap concept that would use a metallic sheet flexible enough to conform to the contours of the orbiter and robust enough to protect any problem area from catastrophic failure during reentry. The simplified view of the application of a refractory metal sheet over a mockup of shuttle orbiter panel 9, which experiences the highest temperatures on the shuttle during reentry is shown. The metallic overwrap concept is attractive because of its versatility as well as the ease with which it can be included in an onboard repair kit. Reentry of the orbiter into Earth's atmosphere imposes extreme requirements on repair materials. Temperatures can exceed 1650 C for up to 15 min in the presence of an extremely oxidizing plasma environment. Several other factors are critical, including catalysity, emissivity, and vibrational and aerodynamic loads. Materials chosen for this application will need to be evaluated with respect to high-temperature capability, resistance to oxidation, strength, coefficient of thermal expansion, and thermal conductivity. The temperature profile across panel 9 during reentry as well as a schematic of the overwrap concept itself is shown.

  6. Structural Studies of Clean and Adsorbate-Covered Fcc Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Statiris, Panayiotis Athanasiou

    We have used medium energy ion scattering (MEIS) to study the structural and vibrational properties of the clean metal surfaces of Ni(110) and Ag(111), the structural changes induced by the presence of small amounts ( {~}1 atomic layer) of heteroatoms on the Ni(001) and Ni(110) surfaces (Cs, K, K and CO on Ni(110) and Au on Ni(001)) as well as the arrangement of the heteroatoms on the surface. The thesis consists of five chapters two of which serve as an introduction and provide general information about metal surfaces and medium energy ion scattering (chapters 1 and 2) and three chapters (3, 4, 5) in which the experimental results are being presented, and structural models are proposed for the surfaces studied. The purpose of the material contained in chapter one is to familiarize the reader with the general concepts, and provide an overview of the progress (experimental and theoretical) in the field of clean and adsorbate covered metal surfaces. The second chapter contains an extensive discussion about the principles and applications of medium energy ion scattering. A study of the structure of the clean Ni(001) surface and the K/Ni(110) and K/CO/Ni(110) surfaces is presented in chapter 3. Both the K/Ni(110) and K/CO/Ni(110) exhibit the missing row reconstruction. The change in the surface unit cell observed upon adsorption of CO atoms on the K/Ni(110) surface observed with low energy electron diffraction is due to the ordering of the CO molecules. The growth and structure of thin Au films (0.35 -3 layers) deposited on the Ni(001) surface is the subject of chapter 4. Au forms an almost incommensurate overlayer with a c(2 times 8) unit cell whose structure resembles that of fcc Au(111). The Au atoms exhibit unusually high vibrational amplitudes, indicating the presence of a soft phonon mode as predicted by theoretical work. The growth mode resembles the Stranski-Krastanov mode without exactly following it. The temperature dependence of the vibrational amplitudes

  7. Small caliber covered self-expanding metal stents in the management of malignant dysphagia

    PubMed Central

    Kucera, Stephen; Barthel, James; Klapman, Jason; Shridhar, Ravi; Hoffe, Sarah; Harris, Cynthia; Almhanna, Khaldoun

    2016-01-01

    Background Use of large caliber [≥18 mm body diameter (BD)] self-expanding metal stents (SEMS) for management of malignant dysphasia is associated with substantial adverse event (AE) and mortality rates (MRs). We sought to determine dysphagia response, stent migration rates, and AE and MRs, for small caliber covered SEMS (sccSEMS) with BDs between 10–16 mm in malignant dysphagia. Methods Thirty-one patients underwent direct endoscopic placement of 50 sccSEMS between January 2008 and March 2011. Patients were monitored for change in dysphagia score (DS), stent migration, AEs, and death through May 2011. Results DS improved in 30 of 31 patients (97%). The median DS decreased from 3 to 2 (P<0.0001). The median effective duration of first sccSEMS placement was 116 (95% CI: 75–196) days. Major and minor AE rates were 6.5% and 19.4% respectively. No stent related deaths were encountered. The overall migration rate was 36% (18/50). The anticipated migration rate was 45.7% (16/35) and the unanticipated migration rate was 13.3% (2/15) (P=0.052). Positive effective clinical outcome occurred in 93.5% (29/31) of cases. Conclusions In malignant dysphagia, direct endoscopic sccSEMS placement provided acceptable dysphagia control and migration rates with substantial reductions in stent related AEs and MRs compared to those reported for large caliber SEMS. PMID:27284474

  8. Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

    PubMed Central

    Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

    2017-01-01

    IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P < .001). Given the prespecified noninferiority margin of −15%, the

  9. Biotic ligand model, a flexible tool for developing site-specific water quality guidelines for metals.

    PubMed

    Niyogi, Soumya; Wood, Chris M

    2004-12-01

    The biotic ligand model (BLM) is a mechanistic approach that greatly improves our ability to generate site-specific ambient water quality criteria (AWQC)for metals in the natural environment relative to conventional relationships based only on hardness. The model is flexible; all aspects of water chemistry that affect toxicity can be included, so the BLM integrates the concept of bioavailability into AWQC--in essence the computational equivalent of water effect ratio (WER) testing. The theory of the BLM evolved from the gill surface interaction model (GSIM) and the free ion activity model (FIAM). Using an equilibrium geochemical modeling framework, the BLM incorporates the competition of the free metal ion with other naturally occurring cations (e.g., Ca2+, Na+, Mg2-, H+), togetherwith complexation by abiotic ligands [e.g., DOM (dissolved organic matter), chloride, carbonates, sulfide] for binding with the biotic ligand, the site of toxic action on the organism. On the basis of fish gill research, the biotic ligands appear to be active ion uptake pathways (e.g., Na+ transporters for copper and silver, Ca2+ transporters for zinc, cadmium, lead, and cobalt), whose geochemical characteristics (affinity = log K, capacity = Bmax) can be quantified in short-term (3-24 h) in vivo gill binding tests. In general, the greater the toxicity of a particular metal, the higher the log K. The BLM quantitatively relates short-term binding to acute toxicity, with the LA50 (lethal accumulation) being predictive of the LC50 (generally 96 h for fish, 48 h for daphnids). We critically evaluate currently available BLMs for copper, silver, zinc, and nickel and gill binding approaches for cadmium, lead, and cobalt on which BLMs could be based. Most BLMs originate from tests with fish and have been recalibrated for more sensitive daphnids by adjustment of LA50 so as to fit the results of toxicity testing. Issues of concern include the arbitrary nature of LA50 adjustments; possible

  10. Reduction of front-metallization grid shading in concentrator cells through laser micro-grooved cover glass

    SciTech Connect

    García-Linares, Pablo Voarino, Philippe; Besson, Pierre; Baudrit, Mathieu; Dominguez, César; Dellea, Olivier; Fugier, Pascal

    2015-09-28

    Concentrator solar cell front-grid metallizations are designed so that the trade-off between series resistance and shading factor (SF) is optimized for a particular irradiance. High concentrator photovoltaics (CPV) typically requires a metallic electrode pattern that covers up to 10% of the cell surface. The shading effect produced by this front electrode results in a significant reduction in short-circuit current (I{sub SC}) and hence, in a significant efficiency loss. In this work we present a cover glass (originally meant to protect the cell surface) that is laser-grooved with a micrometric pattern that redirects the incident solar light towards interfinger regions and away from the metallic electrodes, where they would be wasted in terms of photovoltaic generation. Quantum efficiency (QE) and current (I)-voltage (V) characterization under concentration validate the proof-of-concept, showing great potential for CPV applications.

  11. Reduction of front-metallization grid shading in concentrator cells through laser micro-grooved cover glass

    NASA Astrophysics Data System (ADS)

    García-Linares, Pablo; Voarino, Philippe; Dominguez, César; Dellea, Olivier; Besson, Pierre; Fugier, Pascal; Baudrit, Mathieu

    2015-09-01

    Concentrator solar cell front-grid metallizations are designed so that the trade-off between series resistance and shading factor (SF) is optimized for a particular irradiance. High concentrator photovoltaics (CPV) typically requires a metallic electrode pattern that covers up to 10% of the cell surface. The shading effect produced by this front electrode results in a significant reduction in short-circuit current (ISC) and hence, in a significant efficiency loss. In this work we present a cover glass (originally meant to protect the cell surface) that is laser-grooved with a micrometric pattern that redirects the incident solar light towards interfinger regions and away from the metallic electrodes, where they would be wasted in terms of photovoltaic generation. Quantum efficiency (QE) and current (I)-voltage (V) characterization under concentration validate the proof-of-concept, showing great potential for CPV applications.

  12. Can we judge an oxide by its cover? The case of the metal/oxide interface from first principles

    NASA Astrophysics Data System (ADS)

    Caspary Toroker, Maytal

    Metal/metal-oxide interfaces appear in a wide variety of disciplines including electronics, corrosion, electrochemistry, and catalysis. Specifically, covering a metal-oxide with a metal is often thought to enhance solar energy absorption and to improve photocatalytic activity. For example, the platinum/hematite (Pt/ α-Fe2O3) interface has demonstrated improved functionality. In order to advance our understanding of how metal coverage over an oxide helps performance, we characterize the geometry and electronic structure of the Pt/ α-Fe2O3 interface. We investigate the interface using density functional theory +U, and find a stable crystallographic orientation relationship that agrees with experiment. Furthermore, there are significant changes in the electronic structure of α-Fe2O3 as a result of Pt coverage. We therefore suggest the concept of ``judging'' the electronic properties of an oxide only with its cover. Specifically, covering Fe2O3 with Pt reduces carrier effective mass and creates a continuum of states in the band gap. The former could be beneficial for catalytic activity, while the latter may cause surface recombination. In order to circumvent this problem, we suggest putting metal coverage behind the oxide and far from the electrolyte in a photoelectrochemical device in order to quickly collect electron carriers and avoid recombination with vulnerable holes accumulating as a result of catalysis at the surface. Reference: O. Neufeld and M. Caspary Toroker, ``Can we judge an oxide by its cover? The case of platinum over alpha-Fe2O3 from first principles'', Phys. Chem. Chem. Phys. 17, 24129 (2015). This research was supported by the Morantz Energy Research Fund, the Nancy and Stephen Grand Technion Energy Program, the I-CORE Program of the Planning and Budgeting Committee, and The Israel Science Foundation (Grant No. 152/11).

  13. Methane storage in flexible metal-organic frameworks with intrinsic thermal management

    NASA Astrophysics Data System (ADS)

    Mason, Jarad A.; Oktawiec, Julia; Taylor, Mercedes K.; Hudson, Matthew R.; Rodriguez, Julien; Bachman, Jonathan E.; Gonzalez, Miguel I.; Cervellino, Antonio; Guagliardi, Antonietta; Brown, Craig M.; Llewellyn, Philip L.; Masciocchi, Norberto; Long, Jeffrey R.

    2015-11-01

    As a cleaner, cheaper, and more globally evenly distributed fuel, natural gas has considerable environmental, economic, and political advantages over petroleum as a source of energy for the transportation sector. Despite these benefits, its low volumetric energy density at ambient temperature and pressure presents substantial challenges, particularly for light-duty vehicles with little space available for on-board fuel storage. Adsorbed natural gas systems have the potential to store high densities of methane (CH4, the principal component of natural gas) within a porous material at ambient temperature and moderate pressures. Although activated carbons, zeolites, and metal-organic frameworks have been investigated extensively for CH4 storage, there are practical challenges involved in designing systems with high capacities and in managing the thermal fluctuations associated with adsorbing and desorbing gas from the adsorbent. Here, we use a reversible phase transition in a metal-organic framework to maximize the deliverable capacity of CH4 while also providing internal heat management during adsorption and desorption. In particular, the flexible compounds Fe(bdp) and Co(bdp) (bdp2- = 1,4-benzenedipyrazolate) are shown to undergo a structural phase transition in response to specific CH4 pressures, resulting in adsorption and desorption isotherms that feature a sharp ‘step’. Such behaviour enables greater storage capacities than have been achieved for classical adsorbents, while also reducing the amount of heat released during adsorption and the impact of cooling during desorption. The pressure and energy associated with the phase transition can be tuned either chemically or by application of mechanical pressure.

  14. Design and construction of porous metal-organic frameworks based on flexible BPH pillars

    SciTech Connect

    Hao, Xiang-Rong; Yang, Guang-sheng; Shao, Kui-Zhan; Su, Zhong-Min; Yuan, Gang; Wang, Xin-Long

    2013-02-15

    Three metal-organic frameworks (MOFs), [Co{sub 2}(BPDC){sub 2}(4-BPH){center_dot}3DMF]{sub n} (1), [Cd{sub 2}(BPDC){sub 2}(4-BPH){sub 2}{center_dot}2DMF]{sub n} (2) and [Ni{sub 2}(BDC){sub 2}(3-BPH){sub 2} (H{sub 2}O){center_dot}4DMF]{sub n} (3) (H{sub 2}BPDC=biphenyl-4,4 Prime -dicarboxylic acid, H{sub 2}BDC=terephthalic acid, BPH=bis(pyridinylethylidene)hydrazine and DMF=N,N Prime -dimethylformamide), have been solvothermally synthesized based on the insertion of heterogeneous BPH pillars. Framework 1 has 'single-pillared' MOF-5-like motif with inner cage diameters of up to 18.6 A. Framework 2 has 'double pillared' MOF-5-like motif with cage diameters of 19.2 A while 3 has 'double pillared' 8-connected framework with channel diameters of 11.0 A. Powder X-ray diffraction (PXRD) shows that 3 is a dynamic porous framework. - Graphical abstract: By insertion of flexible BPH pillars based on 'pillaring' strategy, three metal-organic frameworks are obtained showing that the porous frameworks can be constructed in a much greater variety. Highlights: Black-Right-Pointing-Pointer Frameworks 1 and 2 have MOF-5 like motif. Black-Right-Pointing-Pointer The cube-like cages in 1 and 2 are quite large, comparable to the IRMOF-10. Black-Right-Pointing-Pointer Framework 1 is 'single-pillared' mode while 2 is 'double-pillared' mode. Black-Right-Pointing-Pointer PXRD and gas adsorption analysis show that 3 is a dynamic porous framework.

  15. Methane storage in flexible metal-organic frameworks with intrinsic thermal management.

    PubMed

    Mason, Jarad A; Oktawiec, Julia; Taylor, Mercedes K; Hudson, Matthew R; Rodriguez, Julien; Bachman, Jonathan E; Gonzalez, Miguel I; Cervellino, Antonio; Guagliardi, Antonietta; Brown, Craig M; Llewellyn, Philip L; Masciocchi, Norberto; Long, Jeffrey R

    2015-11-19

    As a cleaner, cheaper, and more globally evenly distributed fuel, natural gas has considerable environmental, economic, and political advantages over petroleum as a source of energy for the transportation sector. Despite these benefits, its low volumetric energy density at ambient temperature and pressure presents substantial challenges, particularly for light-duty vehicles with little space available for on-board fuel storage. Adsorbed natural gas systems have the potential to store high densities of methane (CH4, the principal component of natural gas) within a porous material at ambient temperature and moderate pressures. Although activated carbons, zeolites, and metal-organic frameworks have been investigated extensively for CH4 storage, there are practical challenges involved in designing systems with high capacities and in managing the thermal fluctuations associated with adsorbing and desorbing gas from the adsorbent. Here, we use a reversible phase transition in a metal-organic framework to maximize the deliverable capacity of CH4 while also providing internal heat management during adsorption and desorption. In particular, the flexible compounds Fe(bdp) and Co(bdp) (bdp(2-) = 1,4-benzenedipyrazolate) are shown to undergo a structural phase transition in response to specific CH4 pressures, resulting in adsorption and desorption isotherms that feature a sharp 'step'. Such behaviour enables greater storage capacities than have been achieved for classical adsorbents, while also reducing the amount of heat released during adsorption and the impact of cooling during desorption. The pressure and energy associated with the phase transition can be tuned either chemically or by application of mechanical pressure.

  16. Use of Fully Covered Self-Expanding Metal Biliary Stents in Pediatrics: A Case Series.

    PubMed

    Mark, Jacob A; Mack, Cara L; Marwan, Ahmed I; Kramer, Robert E

    2017-08-23

    Endoscopic retrograde cholangiopancreatography (ERCP) is used to manage biliary pathology in pediatric patients. Plastic biliary stents have been utilized in this population for obstructive lesions and bile leaks, however they are sometimes not effective due to migration, occlusion, or ineffective sealing. Fully covered self-expanding metal stents (FCSEMS) have larger diameters making them more suitable for some situations. However, their use in pediatrics has not been defined. The aim of this study is to describe our experience with FCSEMS at our institution. We present a series of all patients who underwent FCSEMS placement at Children's Hospital Colorado including three adolescents and one young adult with complex medical needs. Patient age range was 12-24 years and the weight ranged between 36-75 kg. All patients underwent previous ERCP and one or more rounds of plastic stenting without adequate clinical response prior to consideration of FCSEMS placement. Indications included: 1) Recalcitrant biliary anastomotic stricture post liver transplant, 2) Persistent bile leak after needle perforation, 3) Recurrent obstructive choledocholithiasis after cholecystectomy, and 4) Malignant biliary stricture. Sizes of FCSEMS depended on patient bile duct size and biliary pathology. Dwell time was 6-8 weeks. Three patients had resolution of biliary pathology after FCSEMS therapy. One patient had distal migration of FCSEMS necessitating repeat stenting. There were no adverse events from FCSEMS placement or removal. FCSEMS therapy should be considered in appropriate pediatric patients when plastic biliary stents are not effective. Further studies are needed to evaluate the safety and efficacy of FCSEMS in the pediatric age group.

  17. Evaluation of anti-migration properties of biliary covered self-expandable metal stents.

    PubMed

    Minaga, Kosuke; Kitano, Masayuki; Imai, Hajime; Harwani, Yogesh; Yamao, Kentaro; Kamata, Ken; Miyata, Takeshi; Omoto, Shunsuke; Kadosaka, Kumpei; Sakurai, Toshiharu; Nishida, Naoshi; Kudo, Masatoshi

    2016-08-14

    To assess anti-migration potential of six biliary covered self-expandable metal stents (C-SEMSs) by using a newly designed phantom model. In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration (RFM) was measured by a force gauge on the stent end. Radial force (RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare (ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model. Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables (ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state. RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

  18. Ultra-Flexible, Invisible Thin-Film Transistors Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends

    DTIC Science & Technology

    2015-02-25

    2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim2390 wileyonlinelibrary.com C O M M U N IC A TI O N Ultra-Flexible, “ Invisible ” Thin-Film...enable fully trans- parent thin-fi lm transistors (TFTs), which are essential for the fabrication of “ invisible ” circuits and to increase the...4. TITLE AND SUBTITLE Ultra-Flexible, ’ Invisible ’ Thin-Film Transistors Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends 5a. CONTRACT

  19. Probing the structural flexibility of MOFs by constructing metal oxide@MOF-based heterostructures for size-selective photoelectrochemical response

    NASA Astrophysics Data System (ADS)

    Zhan, Wenwen; He, Yue; Guo, Jiangbin; Chen, Luning; Kong, Xiangjian; Zhao, Haixia; Kuang, Qin; Xie, Zhaoxiong; Zheng, Lansun

    2016-07-01

    It is becoming a challenge to achieve simpler characterization and wider application of flexible metal organic frameworks (MOFs) exhibiting the gate-opening or breathing behavior. Herein, we designed an intelligent MOF-based system where the gate-opening or breathing behavior of MOFs can be facially visualized in solution. Two types of metal oxide@MOF core-shell heterostructures, ZnO@ZIF-7 and ZnO@ZIF-71, were prepared using ZnO nanorods as self-sacrificial templates. The structural flexibility of both the MOFs can be easily judged from the distinct molecular-size-related formation modes and photoelectrochemical performances between the two ZnO@ZIF heterostructures. Moreover, the rotational dynamics of the flexible parts of ZIF-7 were studied by analyzing the intrinsic physical properties, such as dielectric constants, of the structure. The present work reminds us to pay particular attention to the influences of the structural flexibility of MOFs on the structure and properties of MOF-involved heterostructures in future studies.It is becoming a challenge to achieve simpler characterization and wider application of flexible metal organic frameworks (MOFs) exhibiting the gate-opening or breathing behavior. Herein, we designed an intelligent MOF-based system where the gate-opening or breathing behavior of MOFs can be facially visualized in solution. Two types of metal oxide@MOF core-shell heterostructures, ZnO@ZIF-7 and ZnO@ZIF-71, were prepared using ZnO nanorods as self-sacrificial templates. The structural flexibility of both the MOFs can be easily judged from the distinct molecular-size-related formation modes and photoelectrochemical performances between the two ZnO@ZIF heterostructures. Moreover, the rotational dynamics of the flexible parts of ZIF-7 were studied by analyzing the intrinsic physical properties, such as dielectric constants, of the structure. The present work reminds us to pay particular attention to the influences of the structural flexibility of

  20. Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes.

    PubMed

    Bae, Jichul; Benoit, Diane L; Watson, Alan K

    2016-06-01

    In southern Québec, supplement roadside ground covers (i.e. Trifolium spp.) struggle to establish near edges of major roads and thus fail to assist turf recruitment. It creates empty niches vulnerable to weed establishment such as common ragweed (Ambrosia artemisiifolia). We hypothesized that heavy metal stresses may drive such species shifts along roadside edges. A growth chamber experiment was conducted to assess effects of metals (Zn, Pb, Ni, Cu, and Cd) on germination and seedling behaviors of roadside weed (A. artemisiifolia) and ground cover legumes (Coronilla varia, Lotus corniculatus, and Trifolium arvense). All metals inhibited T. arvense germination, but the effect was least on A. artemisiifolia. Low levels of Pb and Ni promoted germination initiation of A. artemisiifolia. Germination of L. corniculatus was not affected by Zn, Pb, and Ni, but inhibited by Cu and Cd. Germination of C. varia was decreased by Ni, Cu, and Cd and delayed by Zn and Pb. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth. Seedling mortality was lowest in A. artemisiifolia but highest in T. arvense when exposed to the metal treatments. L. corniculatus and C. varia seedlings survived when subjected to high levels of Zn, Pb, and Cd. In conclusion, the successful establishment of A. artemisiifolia along roadside edges can be associated with its greater tolerance of heavy metals. The findings also revealed that L. corniculatus is a potential candidate for supplement ground cover in metal-contaminated roadside edges in southern Québec, especially sites contaminated with Zn and Pb.

  1. Hexagonal boron nitride cover on Pt(111): a new route to tune molecule-metal interaction and metal-catalyzed reactions.

    PubMed

    Zhang, Yanhong; Weng, Xuefei; Li, Huan; Li, Haobo; Wei, Mingming; Xiao, Jianping; Liu, Zhi; Chen, Mingshu; Fu, Qiang; Bao, Xinhe

    2015-05-13

    In heterogeneous catalysis molecule-metal interaction is often modulated through structural modifications at the surface or under the surface of the metal catalyst. Here, we suggest an alternative way toward this modulation by placing a two-dimensional (2D) cover on the metal surface. As an illustration, CO adsorption on Pt(111) surface has been studied under 2D hexagonal boron nitride (h-BN) overlayer. Dynamic imaging data from surface electron microscopy and in situ surface spectroscopic results under near ambient pressure conditions confirm that CO molecules readily intercalate monolayer h-BN sheets on Pt(111) in CO atmosphere but desorb from the h-BN/Pt(111) interface even around room temperature in ultrahigh vacuum. The interaction of CO with Pt has been strongly weakened due to the confinement effect of the h-BN cover, and consequently, CO oxidation at the h-BN/Pt(111) interface was enhanced thanks to the alleviated CO poisoning effect.

  2. Enhanced Flexible Thermoelectric Generators Based on Oxide-Metal Composite Materials

    NASA Astrophysics Data System (ADS)

    Geppert, Benjamin; Brittner, Artur; Helmich, Lailah; Bittner, Michael; Feldhoff, Armin

    2017-04-01

    The thermoelectric performance of flexible thermoelectric generator stripes was investigated in terms of different material combinations. The thermoelectric generators were constructed using Cu-Ni-Mn alloy as n-type legs while varying the p-type leg material by including a metallic silver phase and an oxidic copper phase. For the synthesis of Ca_3Co_4O9/CuO/Ag ceramic-based composite materials, silver and the copper were added to the sol-gel batches in the form of nitrates. For both additional elements, the isothermal specific electronic conductivity increases with increasing amounts of Ag and CuO in the samples. The amounts for Ag and Cu were 0 mol.%, 2 mol.%, 5 mol.%, 10 mol.%, and 20 mol.%. The phases were confirmed by x-ray diffraction. Furthermore, secondary electron microscopy including energy dispersive x-ray spectroscopy were processed in the scanning electron microscope and the transmission electron microscope. For each p-type material, the data for the thermoelectric parameters, isothermal specific electronic conductivity σ and the Seebeck coefficient α, were determined. The p-type material with a content of 5 mol.% Ag and Cu exhibited a local maximum of the power factor and led to the generator with the highest electric power output P_el.

  3. Two metal-organic frameworks with different configurations constructed from a flexible tripodal triaromatic acid

    NASA Astrophysics Data System (ADS)

    Liang, Li-Li; Xu, Lei; Xue, Hong-Bao; Tao, Zhao-Lin; Chen, Fei-Jian

    2016-12-01

    Two metal-organic frameworks [Ce2(L)2(DMF)4] (1), and [Ni3(HL2-)4(bpe)3(H2O)4]·[H2N(CH3)2+]2(DMF)6(H2O)8 (2) (H3L = 4,4‧,4″-{[(2,4,6-trimethylbenzene-1,3,5-triyl)tris-(methylene)] tris(oxy)}tribenzoic acid, bpe = trans-4,4‧-bipyridylethylene) have been solvothermally synthesized from a flexible tripodal ligand. Single-crystal X-ray diffraction shows that compound 1 features a 3,6-connected double-layer network which is further connected by weak π-π interactions between benzene rings to form a 3D porous network. Compound 2 exhibits an unprecedented (4,5)-connected (33.42.5.62.72)2(6.84.10) topology based on zigzag chains and straight chains. In addition, thermal stabilities and luminescent properties of 1 and 2 were investigated in the solid state.

  4. Effective surface modification by chemical solution deposition for flexible metal substrates

    NASA Astrophysics Data System (ADS)

    Du, Wei; Bai, Yue-Ling; Wang, Jing; Fang, Jianhui; Fan, Feng; Liu, Zhiyong; Guo, Yanqun; Bai, Chuanyi; Cai, Chuanbing

    2017-03-01

    Solution deposition planarization (SDP) was used to modify the flexible metal substrates for high temperature superconductor (HTS) tapes to ensure an available and effective surface for subsequent growth of buffer films. The surface morphologies with different tape speeds and coating layers were systematically investigated. 16 layers SDP-films decreased the surface roughness (RMS) from 11.74 to 0.788 nm for Hastelloy C-276 and 12 layers SDP-films decreased the RMS from 20.93 to 0.903 nm for SUS 304. Follow-up study confirmed that the low value of RMS (<1 nm) and high reflectivity of SDP-films exhibit superior characteristics for ion beam-assisted deposited (IBAD)-MgO, sputtered LaMnO3 films and YBCO films. A 10 m sample verified the stability of SDP-films on Hastelloy. The similar result for achieved SDP-films on SUS 304 (I cAVG  =  110.1 A) and Hastelloy (I cAVG  =  124.5 A) revealed the stainless steel has potential application value for coated conductor, which further reduced the cost of raw materials.

  5. Flexible FETs using ultrathin Si microwires embedded in solution processed dielectric and metal layers

    NASA Astrophysics Data System (ADS)

    Khan, S.; Yogeswaran, N.; Taube, W.; Lorenzelli, L.; Dahiya, R.

    2015-12-01

    This work presents a novel manufacturing route for obtaining high performance bendable field effect transistors (FET) by embedding silicon (Si) microwires (2.5 μm thick) in layers of solution-processed dielectric and metallic layers. The objective of this study is to explore heterogeneous integration of Si with polymers and to exploit the benefits of both microelectronics and printing technologies. Arrays of Si microwires are developed on silicon on insulator (SOI) wafers and transfer printed to polyimide (PI) substrate through a polydimethylsiloxane (PDMS) carrier stamp. Following the transfer printing of Si microwires, two different processing steps were developed to obtain top gate top contact and back gate top contact FETs. Electrical characterizations indicate devices having mobility as high as 117.5 cm2 V-1 s-1. The fabricated devices were also modeled using SILVACO Atlas. Simulation results show a trend in the electrical response similar to that of experimental results. In addition, a cyclic test was performed to demonstrate the reliability and mechanical robustness of the Si μ-wires on flexible substrates.

  6. Implantable liquid metal-based flexible neural microelectrode array and its application in recovering animal locomotion functions

    NASA Astrophysics Data System (ADS)

    Guo, Rui; Liu, Jing

    2017-10-01

    With significant advantages in rapidly restoring the nerve function, electrical stimulation of nervous tissue is a crucial treatment of peripheral nerve injuries leading to common movement disorder. However, the currently available stimulating electrodes generally based on rigid conductive materials would cause a potential mechanical mismatch with soft neural tissues which thus reduces long-term effects of electrical stimulation. Here, we proposed and fabricated a flexible neural microelectrode array system based on the liquid metal GaIn alloy (75.5% Ga and 24.5% In by weight) and via printing approach. Such an alloy with a unique low melting point (10.35 °C) owns excellent electrical conductivity and high compliance, which are beneficial to serve as implantable flexible neural electrodes. The flexible neural microelectrode array embeds four liquid metal electrodes and stretchable interconnects in a PDMS membrane (500 µm in thickness) that possess a lower elastic modulus (1.055 MPa), which is similar to neural tissues with elastic moduli in the 0.1–1.5 MPa range. The electrical experiments indicate that the liquid metal interconnects could sustain over 7000 mechanical stretch cycles with resistance approximately staying at 4 Ω. Over the conceptual experiments on animal sciatic nerve electrical stimulation, the dead bullfrog implanted with flexible neural microelectrode array could even rhythmically contract and move its lower limbs under the electrical stimulations from the implant. This demonstrates a highly efficient way for quickly recovering biological nerve functions. Further, the good biocompatibility of the liquid metal material was justified via a series of biological experiments. This liquid metal modality for neural stimulation is expected to play important roles as biologic electrodes to overcome the fundamental mismatch in mechanics between biological tissues and electronic devices in the coming time.

  7. Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

    PubMed

    Kida, M; Miyazawa, S; Iwai, T; Ikeda, H; Takezawa, M; Kikuchi, H; Watanabe, M; Imaizumi, H; Koizumi, W

    2011-12-01

    Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention. © Georg Thieme Verlag KG Stuttgart · New York.

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

    NASA Astrophysics Data System (ADS)

    Kim, Juho; Hwang, Jeongwoo; Song, Kwangsun; Kim, Namyun; Shin, Jae Cheol; Lee, Jongho

    2016-06-01

    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 power 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.

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

    SciTech Connect

    Kim, Juho; Song, Kwangsun; Kim, Namyun; Lee, Jongho; Hwang, Jeongwoo; Shin, Jae Cheol

    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 power 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.

  10. Noise and vibration level reduction by covering metal structures with layers of damping materials. [considering viscoelastic insulation layers

    NASA Technical Reports Server (NTRS)

    Rugina, I.; Paven, H. T. O.

    1974-01-01

    One of the most important methods of reducing the noise and vibration level is the damping of the secondary sources, such as metal plates, often used in vehicle structures, by means of covering materials with high internal viscosity. Damping layers are chosen at an optimum thickness corresponding to the frequency and temperature range in which a certain structure works. The structure's response corresponding to various real situations is analyzed by means of a measuring chain including electroacoustical or electromechanical transducers. The experimental results provide the dependence of the loss factor and damping transmission coefficient as a function of the damping layer thickness or of the frequency for various viscoelastic covering materials.

  11. Arterial bleeding during EUS-guided pseudocyst drainage stopped by placement of a covered self-expandable metal stent

    PubMed Central

    2013-01-01

    Background Hemorrhagic complications during EUS-guided pseudocyst drainage can occur, because the vessels on the internal wall of the pseudocyst might be compressed by the fluid and thus not visible on color Doppler or even power Doppler EUS. Case presentation We report a case of an immediate internal spurting arterial bleeding precipitated during EUS-guided pseudocyst drainage which stopped instantaneously by placement of a double flanged covered self-expandable metal stent through mechanical hemostasis. Conclusion In an unusual situation of bleeding from collateral circulation near the pseudocyst wall during pseudocyst drainage, the placement of an expandable metal stent proved to be useful. PMID:23706101

  12. Nonvacuum, maskless fabrication of a flexible metal grid transparent conductor by low-temperature selective laser sintering of nanoparticle ink.

    PubMed

    Hong, Sukjoon; Yeo, Junyeob; Kim, Gunho; Kim, Dongkyu; Lee, Habeom; Kwon, Jinhyeong; Lee, Hyungman; Lee, Phillip; Ko, Seung Hwan

    2013-06-25

    We introduce a facile approach to fabricate a metallic grid transparent conductor on a flexible substrate using selective laser sintering of metal nanoparticle ink. The metallic grid transparent conductors with high transmittance (>85%) and low sheet resistance (30 Ω/sq) are readily produced on glass and polymer substrates at large scale without any vacuum or high-temperature environment. Being a maskless direct writing method, the shape and the parameters of the grid can be easily changed by CAD data. The resultant metallic grid also showed a superior stability in terms of adhesion and bending. This transparent conductor is further applied to the touch screen panel, and it is confirmed that the final device operates firmly under continuous mechanical stress.

  13. Successful management of benign biliary strictures with fully covered self-expanding metal stents.

    PubMed

    Devière, Jacques; Nageshwar Reddy, D; Püspök, Andreas; Ponchon, Thierry; Bruno, Marco J; Bourke, Michael J; Neuhaus, Horst; Roy, André; González-Huix Lladó, Ferrán; Barkun, Alan N; Kortan, Paul P; Navarrete, Claudio; Peetermans, Joyce; Blero, Daniel; Lakhtakia, Sundeep; Dolak, Werner; Lepilliez, Vincent; Poley, Jan W; Tringali, Andrea; Costamagna, Guido

    2014-08-01

    Fully covered self-expanding metal stents (FCSEMS) are gaining acceptance for the treatment of benign biliary strictures. We performed a large prospective multinational study to study the ability to remove these stents after extended indwell and the frequency and durability of stricture resolution. In a nonrandomized study at 13 centers in 11 countries, 187 patients with benign biliary strictures received FCSEMS. Removal was scheduled at 10-12 months for patients with chronic pancreatitis or cholecystectomy and at 4-6 months for patients who received liver transplants. The primary outcome measure was removal success, defined as either scheduled endoscopic removal of the stent with no removal-related serious adverse events or spontaneous stent passage without the need for immediate restenting. Endoscopic removal of FCSEMS was not performed for 10 patients because of death (from unrelated causes), withdrawal of consent, or switch to palliative treatment. For the remaining 177 patients, removal success was accomplished in 74.6% (95% confidence interval [CI], 67.5%-80.8%). Removal success was more frequent in the chronic pancreatitis group (80.5%) than in the liver transplantation (63.4%) or cholecystectomy (61.1%) groups (P = .017). FCSEMS were removed by endoscopy from all patients in whom this procedure was attempted. Stricture resolution without restenting upon FCSEMS removal occurred in 76.3% of patients (95% CI, 69.3%-82.3%). The rate of resolution was lower in patients with FCSEMS migration (odds ratio, 0.22; 95% CI, 0.11-0.46). Over a median follow-up period of 20.3 months (interquartile range, 12.9-24.3 mo), the rate of stricture recurrence was 14.8% (95% CI, 8.2%-20.9%). Stent- or removal-related serious adverse events, most often cholangitis, occurred in 27.3% of patients. There was no stent- or removal-related mortality. In a large prospective multinational study, removal success of FCSEMS after extended indwell and stricture resolution were achieved for

  14. Metal Decoration Effects on the Gas-Sensing Properties of 2D Hybrid-Structures on Flexible Substrates

    PubMed Central

    Cho, Byungjin; Yoon, Jongwon; Lim, Sung Kwan; Kim, Ah Ra; Choi, Sun-Young; Kim, Dong-Ho; Lee, Kyu Hwan; Lee, Byoung Hun; Ko, Heung Cho; Hahm, Myung Gwan

    2015-01-01

    We have investigated the effects of metal decoration on the gas-sensing properties of a device with two-dimensional (2D) molybdenum disulfide (MoS2) flake channels and graphene electrodes. The 2D hybrid-structure device sensitively detected NO2 gas molecules (>1.2 ppm) as well as NH3 (>10 ppm). Metal nanoparticles (NPs) could tune the electronic properties of the 2D graphene/MoS2 device, increasing sensitivity to a specific gas molecule. For instance, palladium NPs accumulate hole carriers of graphene/MoS2, electronically sensitizing NH3 gas molecules. Contrarily, aluminum NPs deplete hole carriers, enhancing NO2 sensitivity. The synergistic combination of metal NPs and 2D hybrid layers could be also applied to a flexible gas sensor. There was no serious degradation in the sensing performance of metal-decorated MoS2 flexible devices before/after 5000 bending cycles. Thus, highly sensitive and endurable gas sensor could be achieved through the metal-decorated 2D hybrid-structure, offering a useful route to wearable electronic sensing platforms. PMID:26404279

  15. A Challenge Beyond Bottom Cells: Top-Illuminated Flexible Organic Solar Cells with Nanostructured Dielectric/Metal/Polymer (DMP) Films.

    PubMed

    Ham, Juyoung; Dong, Wan Jae; Park, Jae Yong; Yoo, Chul Jong; Lee, Illhwan; Lee, Jong-Lam

    2015-07-15

    Top-illuminated flexible organic solar cells with a high power conversion efficiency (≈6.75%) are fabricated using a dielectric/metal/polymer (DMP) electrode. Employing a polymer layer (n = 1.49) makes it possible to show the high transmittance, which is insensitive to film thickness, and the excellent haze induced by well-ordered nanopatterns on the DMP electrode, leading to a 28% of enhancement in efficiency compared to bottom cells.

  16. Endosonography-guided drainage of malignant fluid collections using lumen-apposing, fully covered self-expanding metal stents.

    PubMed

    Musumba, Crispin; Tutticci, Nicholas; Nanda, Kavinderjit; Kwan, Vu

    2014-08-01

    Endosonography (EUS)-guided drainage of paragastric fluid collections using fully covered self-expanding metal stents (FCSEMS) is now a well-established procedure. Recently, new and specially designed lumen-apposing, fully-covered metal cystgastrostomy stents have been employed for this indication. In this case series, the use of these new stents for the drainage of malignant fluid collections in three symptomatic patients is described. Cases included a large pancreatic pseudocyst, secondary to underlying acute lymphoblastic leukemia, and two large collections of loculated ascites due to metastatic ovarian and cervical cancer, respectively. Technical success in inserting the new stents was achieved in all three patients, and resulted in symptomatic relief. There were no clinically significant complications directly attributed to the stents. These new lumen-apposing cystgastrostomy stents may provide a viable, minimally invasive, and effective alternative for drainage of malignant fluid collections, either for definitive treatment or for palliation of symptoms.

  17. Functional integrity of flexible n-channel metal-oxide-semiconductor field-effect transistors on a reversibly bistable platform

    NASA Astrophysics Data System (ADS)

    Alfaraj, Nasir; Hussain, Aftab M.; Torres Sevilla, Galo A.; Ghoneim, Mohamed T.; Rojas, Jhonathan P.; Aljedaani, Abdulrahman B.; Hussain, Muhammad M.

    2015-10-01

    Flexibility can bring a new dimension to state-of-the-art electronics, such as rollable displays and integrated circuit systems being transformed into more powerful resources. Flexible electronics are typically hosted on polymeric substrates. Such substrates can be bent and rolled up, but cannot be independently fixed at the rigid perpendicular position necessary to realize rollable display-integrated gadgets and electronics. A reversibly bistable material can assume two stable states in a reversible way: flexibly rolled state and independently unbent state. Such materials are used in cycling and biking safety wristbands and a variety of ankle bracelets for orthopedic healthcare. They are often wrapped around an object with high impulsive force loading. Here, we study the effects of cumulative impulsive force loading on thinned (25 μm) flexible silicon-based n-channel metal-oxide-semiconductor field-effect transistor devices housed on a reversibly bistable flexible platform. We found that the transistors have maintained their high performance level up to an accumulated 180 kN of impact force loading. The gate dielectric layers have maintained their reliability, which is evidenced by the low leakage current densities. Also, we observed low variation in the effective electron mobility values, which manifests that the device channels have maintained their carrier transport properties.

  18. Maximum occurrence analysis of protein conformations for different distributions of paramagnetic metal ions within flexible two-domain proteins.

    PubMed

    Luchinat, Claudio; Nagulapalli, Malini; Parigi, Giacomo; Sgheri, Luca

    2012-02-01

    Multidomain proteins are composed of rigid domains connected by (flexible) linkers. Therefore, the domains may experience a large degree of reciprocal reorientation. Pseudocontact shifts and residual dipolar couplings arising from one or more paramagnetic metals successively placed in a single metal binding site in the protein can be used as restraints to assess the degree of mobility of the different domains. They can be used to determine the maximum occurrence (MO) of each possible protein conformation, i.e. the maximum weight that such conformations can have independently of the real structural ensemble, in agreement with the provided restraints. In the case of two-domain proteins, the metal ions can be placed all in the same domain, or distributed between the two domains. It has been demonstrated that the quantity of independent information for the characterization of the system is larger when all metals are bound in the same domain. At the same time, it has been shown that there are practical advantages in placing the metals in different domains. Here, it is shown that distributing the metals between the domains provides a tool for defining a coefficient of compatibility among the restraints obtained from different metals, without a significant decrease of the capability of the MO values to discriminate among conformations with different weights.

  19. Sludge-Treated Coal Mine Spoils Increase Heavy metals in Cover Crops

    Treesearch

    F. C. McBride; C. Chavengsaksongkram; D. H. Urie

    1977-01-01

    Four species of forage were grown in a greenhouse on acid strip mine spoil treated with municipal sewage sludge. Foliar levels of heavy metals exceeded those recommended for animal consumption. No plant toxicity symptoms were evident.

  20. Next Generation Non-Vacuum, Maskless, Low Temperature Nanoparticle Ink Laser Digital Direct Metal Patterning for a Large Area Flexible Electronics

    PubMed Central

    Yeo, Junyeob; Hong, Sukjoon; Lee, Daehoo; Hotz, Nico; Lee, Ming-Tsang; Grigoropoulos, Costas P.; Ko, Seung Hwan

    2012-01-01

    Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electronics fabrication methods are well developed for rigid substrates, direct application or slight modification of conventional processes for flexible electronics fabrication cannot work. The future flexible electronics fabrication requires totally new low-temperature process development optimized for flexible substrate and it should be based on new material too. Here we present a simple approach to developing a flexible electronics fabrication without using conventional vacuum deposition and photolithography. We found that direct metal patterning based on laser-induced local melting of metal nanoparticle ink is a promising low-temperature alternative to vacuum deposition– and photolithography-based conventional metal patterning processes. The “digital” nature of the proposed direct metal patterning process removes the need for expensive photomask and allows easy design modification and short turnaround time. This new process can be extremely useful for current small-volume, large-variety manufacturing paradigms. Besides, simple, scalable, fast and low-temperature processes can lead to cost-effective fabrication methods on a large-area polymer substrate. The developed process was successfully applied to demonstrate high-quality Ag patterning (2.1 µΩ·cm) and high-performance flexible organic field effect transistor arrays. PMID:22900011

  1. Next generation non-vacuum, maskless, low temperature nanoparticle ink laser digital direct metal patterning for a large area flexible electronics.

    PubMed

    Yeo, Junyeob; Hong, Sukjoon; Lee, Daehoo; Hotz, Nico; Lee, Ming-Tsang; Grigoropoulos, Costas P; Ko, Seung Hwan

    2012-01-01

    Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electronics fabrication methods are well developed for rigid substrates, direct application or slight modification of conventional processes for flexible electronics fabrication cannot work. The future flexible electronics fabrication requires totally new low-temperature process development optimized for flexible substrate and it should be based on new material too. Here we present a simple approach to developing a flexible electronics fabrication without using conventional vacuum deposition and photolithography. We found that direct metal patterning based on laser-induced local melting of metal nanoparticle ink is a promising low-temperature alternative to vacuum deposition- and photolithography-based conventional metal patterning processes. The "digital" nature of the proposed direct metal patterning process removes the need for expensive photomask and allows easy design modification and short turnaround time. This new process can be extremely useful for current small-volume, large-variety manufacturing paradigms. Besides, simple, scalable, fast and low-temperature processes can lead to cost-effective fabrication methods on a large-area polymer substrate. The developed process was successfully applied to demonstrate high-quality Ag patterning (2.1 µΩ·cm) and high-performance flexible organic field effect transistor arrays.

  2. High mobility single-crystalline-like GaAs thin films on inexpensive flexible metal substrates by metal-organic chemical vapor deposition

    SciTech Connect

    Dutta, P. Rathi, M.; Gao, Y.; Yao, Y.; Selvamanickam, V.; Zheng, N.; Ahrenkiel, P.; Martinez, J.

    2014-09-01

    We demonstrate heteroepitaxial growth of single-crystalline-like n and p-type doped GaAs thin films on inexpensive, flexible, and light-weight metal foils by metal-organic chemical vapor deposition. Single-crystalline-like Ge thin film on biaxially textured templates made by ion beam assisted deposition on metal foil served as the epitaxy enabling substrate for GaAs growth. The GaAs films exhibited strong (004) preferred orientation, sharp in-plane texture, low grain misorientation, strong photoluminescence, and a defect density of ∼10{sup 7 }cm{sup −2}. Furthermore, the GaAs films exhibited hole and electron mobilities as high as 66 and 300 cm{sup 2}/V-s, respectively. High mobility single-crystalline-like GaAs thin films on inexpensive metal substrates can pave the path for roll-to-roll manufacturing of flexible III-V solar cells for the mainstream photovoltaics market.

  3. ePTFE/FEP-Covered Metallic Stents for Palliation of MalignantBiliary Disease: Can Tumor Ingrowth Be Prevented?

    SciTech Connect

    Hatzidakis, Adam Krokidis, Miltiadis; Kalbakis, Kostantinos; Romanos, Jiannis; Petrakis, Ioannis; Gourtsoyiannis, Nicholas

    2007-09-15

    Purpose. To determine the application and clinical effectiveness of ePTFE/FEP-covered metallic stents for palliation of malignant biliary disease, and to evaluate the efficiency of stent coverage in preventing tumor ingrowth. Methods. During a 3-year period, 36 patients with malignant obstructive jaundice were treated with ePTFE/FEP-covered stents, with or without proximal side holes. The stricture was located in the lower common bile duct (CBD) in 18 cases, the upper CBD in 9, the lower common hepatic duct (CHD) in 6, and the upper CHD in 3 patients. Results.Thirty-seven covered stents were percutaneously implanted. The technical success rate was 97%. Reintervention was required in 6 cases. The 30-day mortality rate was 40%, not procedure-related. Mean survival was 128 days. Primary patency rates were 100%,55.5%, and 25% at 3, 6, and 12 months, respectively, while the assisted patency rate was 100% at 12 months. Stents without side holes had higher primary patency rates compared with those with side holes, where occlusion was always due to tumor ingrowth. Tumor ingrowth did not occur in the completely covered stents. No stent dysfunction due to sludge incrustation was found.Complications were 1 case of arterial laceration that occurred during percutaneous transhepatic cholangiography, and a subcapsular hematoma and 1 case of bile peritonitis, that both occurred during primary stenting. No complications followed the secondary stenting technique. Conclusion. ePTFE/FEP-covered metallic stents are safe and effective for palliation of malignant biliary disease. The presence of the ePTFE/FEP coating is likely to prevent from tumor ingrowth.

  4. Inorganic-organic hybrid antibiocorrosive covers based on polyurethanes and coordination compounds of some transition metals

    NASA Astrophysics Data System (ADS)

    Lekishvili, N.; Barbakadze, Kh.; Brostow, W.; Datashvili, T.; Fainleib, A.; Grigorieva, O.

    2012-07-01

    Biodegradation of synthetic and natural materials by various microorganisms affects a wide range of industrial processes and techniques. One of the modern ways to protect of the synthetic and natural materials from the action of aggressive microorganisms is a creation of novel antibiocorrosive covers with high bioactivity and multivectorial and directional action based on inorganic-organic hybrid composites [1, 2].

  5. Flexibility and sorption selectivity in rigid metal-organic frameworks: the impact of ether-functionalised linkers.

    PubMed

    Henke, Sebastian; Schmid, Rochus; Grunwaldt, Jan-Dierk; Fischer, Roland A

    2010-12-27

    The functionalisation of well-known rigid metal-organic frameworks (namely, [Zn(4)O(bdc)(3)](n), MOF-5, IRMOF-1 and [Zn(2)(bdc)(2)(dabco)](n); bdc = 1,4-benzene dicarboxylate, dabco = diazabicyclo[2.2.2]octane) with additional alkyl ether groups of the type -O-(CH(2))(n)-O-CH(3) (n = 2-4) initiates unexpected structural flexibility, as well as high sorption selectivity towards CO(2) over N(2) and CH(4) in the porous materials. These novel materials respond to the presence/absence of guest molecules with structural transformations. We found that the chain length of the alkyl ether groups and the substitution pattern of the bdc-type linker have a major impact on structural flexibility and sorption selectivity. Remarkably, our results show that a high crystalline order of the activated material is not a prerequisite to achieve significant porosity and high sorption selectivity.

  6. Polarization Manipulation via Orientation Control in Polycrystalline BiFeO3 Thin Films on Biaxially Textured, Flexible Metallic Tapes

    NASA Astrophysics Data System (ADS)

    Shin, Junsoo; Goyal, Amit; Jesse, Stephen; Heatherly, Lee

    2011-02-01

    (111)-, (101)-, and (001)-oriented polycrystalline BiFeO3 films were fabricated on rolling-assisted biaxially textured substrates (RABiTS) with appropriate engineering of heteroepitaxially grown buffer multilayers on RABiTS. The crystallographic orientation and polarization direction were confirmed using X-ray diffraction and piezoresponse force microscopy (PFM), respectively. All the films exhibited excellent piezoelectric properties. Switching spectroscopy PFM demonstrated that the switching polarization in (111)-oriented polycrystalline BiFeO3 films is higher than that in (101)- or (001)-oriented films. These BiFeO3 films on low-cost, flexible, biaxially textured metallic tapes with controllable orientation and polarization are attractive for application in flexible piezoelectric devices.

  7. In-Situ Formed Hierarchical Metal-Organic Flexible Cathode for High-Energy Sodium-Ion Batteries.

    PubMed

    Huang, Ying; Fang, Chun; Zeng, Rui; Liu, Yaojun; Zhang, Wang; Wang, Yanjie; Liu, Qingju; Huang, Yunhui

    2017-09-10

    Metal-organic compounds are a family of electrode materials with structural diversity and excellent thermal stability for rechargeable batteries. Here, we fabricate a hierarchical nanocomposite with metal-organic cuprous tetracyanoquino- dimethane (CuTCNQ) in three-dimensional (3D) conductive carbon nanofibers (CNFs) network by in-situ growth, and evaluate it as flexible cathode for sodium-ion batteries (SIBs). CuTCNQ in such flexible composite electrode is able to exhibit a superhigh capacity of 252 mAh g-1 at 0.1 C and highly reversible stability for 1200 cycles within the voltage range of 2.5 - 4.1 V (vs. Na+/Na). A high specific energy of 762 Wh kg-1 is obtained with high average potential of 3.2 V (vs. Na+/Na). The in-situ formed electroactive metal-organic composites with tailored nanoarchitecture provide a promising alternative choice for high-performance cathode materials in sodium-ion batteries with high energy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A new route toward ultrasensitive, flexible chemical sensors: metal nanotubes by wet-chemical synthesis along sacrificial nanowire templates.

    PubMed

    Lim, Mi Ae; Kim, Dong Hwan; Park, Chong-Ook; Lee, Young Wook; Han, Sang Woo; Li, Zhiyong; Williams, R Stan; Park, Inkyu

    2012-01-24

    We developed a novel low-temperature, wet-chemical process for the facile synthesis of metal nanotube arrays through the reduction of metal precursors along sacrificial metal oxide nanowire templates and demonstrated its applications to the ultrasensitive, low-power, mechanically robust, and flexible chemical sensors. The in situ dissolution of ZnO nanowire templates, which were hydrothermally grown on electrode surfaces, during the reaction allows the direct formation of tubular Pd nanostructures on the sensor devices without the need of complex processes for device integration or template removal. Moreover, this simple synthesis was carried out at low-temperature with mild chemical conditions; therefore we could make Pd nanotube devices not only on silicon substrates but also on flexible polymer substrates. The H(2) sensing of such Pd nanotube devices was investigated under various mechanical loading and showed excellent reliability and robustness. The sensitivity of our devices was found to be at least 2 orders of magnitude higher than literature values for H(2) sensors, which can be attributed to the high surface area and the well-formed interconnect of Pd tubular nanostructures in our devices.

  9. Metal Nanoparticles Covered with a Metal-Organic Framework: From One-Pot Synthetic Methods to Synergistic Energy Storage and Conversion Functions.

    PubMed

    Kobayashi, Hirokazu; Mitsuka, Yuko; Kitagawa, Hiroshi

    2016-08-01

    Hybrid materials composed of metal nanoparticles and metal-organic frameworks (MOFs) have attracted much attention in many applications, such as enhanced gas storage and catalytic, magnetic, and optical properties, because of the synergetic effects between the metal nanoparticles and MOFs. In this Forum Article, we describe our recent progress on novel synthetic methods to produce metal nanoparticles covered with a MOF (metal@MOF). We first present Pd@copper(II) 1,3,5-benzenetricarboxylate (HKUST-1) as a novel hydrogen-storage material. The HKUST-1 coating on Pd nanocrystals results in a remarkably enhanced hydrogen-storage capacity and speed in the Pd nanocrystals, originating from charge transfer from Pd nanocrystals to HKUST-1. Another material, Pd-Au@Zn(MeIM)2 (ZIF-8, where HMeIM = 2-methylimidazole), exhibits much different catalytic activity for alcohol oxidation compared with Pd-Au nanoparticles, indicating a design guideline for the development of composite catalysts with high selectivity. A composite material composed of Cu nanoparticles and Cr3F(H2O)2O{C6H3(CO2)3}2 (MIL-100-Cr) demonstrates higher catalytic activity for CO2 reduction into methanol than Cu/γ-Al2O3. We also present novel one-pot synthetic methods to produce composite materials including Pd/ZIF-8 and Ni@Ni2(dhtp) (MOF-74, where H4dhtp = 2,5-dihydroxyterephthalic acid).

  10. Partially covered self-expanding metal stent for unresectable malignant extrahepatic biliary obstruction: results of a large prospective series.

    PubMed

    Gómez-Oliva, Cristina; Guarner-Argente, Carlos; Concepción, Mar; Jiménez, Francisco Javier; Rodríguez, Sarbelio; Gonzalez-Huix, Ferran; Mugica, Fernando; Cabriada, José Luis; Rodríguez, Claudio; Aguilar, Carlos Guarner

    2012-01-01

    Endoscopic biliary stenting is a well-established palliative treatment in patients with unresectable malignant biliary strictures. Obstruction of uncovered self-expanding metal stent (SEMS) due to tumor ingrowth is the most frequent complication. Partially covered SEMS might increase stent patency but could favor complications related to stent covering, such as pancreatitis, cholecystitis, and migration. The aim of this study was to evaluate the efficacy and safety of partially covered SEMS in patients with an unresectable malignant biliary stricture. Patients with malignant extrahepatic biliary obstruction treated endoscopically with partially covered SEMS were included in this multicenter, prospective, nonrandomized study. One hundred ninety-nine patients were endoscopically treated with partially covered SEMS in 32 Spanish hospitals. Clinical success after deep cannulation was 96%. Early complications occurred in 4% (3 pancreatitis, 2 cholangitis, 1 hemorrhage, 1 perforation, and 1 cholecystitis). Late complications occurred in 19.5% (18 obstructions, 10 migrations, 6 cholangitis without obstruction, 3 acute cholecystitis, and 2 pancreatitis), with no tumor ingrowth in any case. Median stent patency was 138.9 ± 112.6 days. One-year actuarial probability of stent patency was 70% and that of nonmigration was 86%. Multivariate analysis showed adjuvant radio- or chemotherapy as the only independent predictive factor of stent patency and previous insertion of a biliary stent was the only predictive factor of migration. The partially covered SEMS was easily inserted, had a high clinical success rate, and prevented tumor ingrowth. The incidence of possible complications related to stent coverage, namely, migration, pancreatitis, and cholecystitis, was lower than in previously published series.

  11. Microcavity-Free Broadband Light Outcoupling Enhancement in Flexible Organic Light-Emitting Diodes with Nanostructured Transparent Metal-Dielectric Composite Electrodes.

    PubMed

    Xu, Lu-Hai; Ou, Qing-Dong; Li, Yan-Qing; Zhang, Yi-Bo; Zhao, Xin-Dong; Xiang, Heng-Yang; Chen, Jing-De; Zhou, Lei; Lee, Shuit-Tong; Tang, Jian-Xin

    2016-01-26

    Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new flexible transparent conductive electrodes with superior mechanical, electrical, and optical properties. Herein, an effective nanostructured metal/dielectric composite electrode on a plastic substrate is reported by combining a quasi-random outcoupling structure for broadband and angle-independent light outcoupling of white emission with an ultrathin metal alloy film for optimum optical transparency, electrical conduction, and mechanical flexibility. The microcavity effect and surface plasmonic loss can be remarkably reduced in white flexible OLEDs, resulting in a substantial increase in the external quantum efficiency and power efficiency to 47.2% and 112.4 lm W(-1).

  12. Reorganization of a topological surface state: Theory for Bi2Te3(111) covered by noble metals

    NASA Astrophysics Data System (ADS)

    Muñoz, Francisco; Flieger, Markus; Henk, Jürgen; Mertig, Ingrid

    2014-09-01

    The electronic structure of Bi2Te3 covered by noble metals is investigated by first-principles calculations. The Dirac surface state of the topological insulator Bi2Te3 hybridizes with the sp states of the noble metal, which gives rise to strong reorganization of the surface electronic structure. Striking features of the modified Dirac surface state are (i) the introduction of new Dirac points within the fundamental band gap of Bi2Te3, (ii) a very weak dispersion, and (iii) a multisheeted Fermi surface which results in an orientation-dependent number of conducting channels in the fundamental band gap of Bi2Te3. Our findings have impact for spin-dependent surface transport.

  13. Tuning the Adsorption-Induced Phase Change in the Flexible Metal-Organic Framework Co(bdp).

    PubMed

    Taylor, Mercedes K; Runčevski, Tomče; Oktawiec, Julia; Gonzalez, Miguel I; Siegelman, Rebecca L; Mason, Jarad A; Ye, Jinxing; Brown, Craig M; Long, Jeffrey R

    2016-11-16

    Metal-organic frameworks that flex to undergo structural phase changes upon gas adsorption are promising materials for gas storage and separations, and achieving synthetic control over the pressure at which these changes occur is crucial to the design of such materials for specific applications. To this end, a new family of materials based on the flexible metal-organic framework Co(bdp) (bdp(2-) = 1,4-benzenedipyrazolate) has been prepared via the introduction of fluorine, deuterium, and methyl functional groups on the bdp(2-) ligand, namely, Co(F-bdp), Co(p-F2-bdp), Co(o-F2-bdp), Co(D4-bdp), and Co(p-Me2-bdp). These frameworks are isoreticular to the parent framework and exhibit similar structural flexibility, transitioning from a low-porosity, collapsed phase to high-porosity, expanded phases with increasing gas pressure. Powder X-ray diffraction studies reveal that fluorination of the aryl ring disrupts edge-to-face π-π interactions, which work to stabilize the collapsed phase at low gas pressures, while deuteration preserves these interactions and methylation strengthens them. In agreement with these observations, high-pressure CH4 adsorption isotherms show that the pressure of the CH4-induced framework expansion can be systematically controlled by ligand functionalization, as materials without edge-to-face interactions in the collapsed phase expand at lower CH4 pressures, while frameworks with strengthened edge-to-face interactions expand at higher pressures. Importantly, this work puts forth a general design strategy relevant to many other families of flexible metal-organic frameworks, which will be a powerful tool in optimizing these phase-change materials for industrial applications.

  14. Efficacy of Covered Metallic Stents in the Treatment of Unresectable Malignant Biliary Obstruction

    SciTech Connect

    Miyayama, Shiro Matsui, Osamu; Akakura, Yukari; Yamamoto, Toru; Nishida, Hiroto; Yoneda, Kenji; Kawai, Keiichi; Toya, Daisyu; Tanaka, Nobuyoshi; Mitsui, Takeshi; Asada, Yasuyuki

    2004-08-15

    We evaluated the efficacy of covered stents for malignant biliary obstruction. We studied 62 patients with obstruction distal to the hilar confluence who survived longer than 10 weeks and divided them into a covered stent group (group 1, n = 22), a Z stent group (group 2, n = 19), and a mesh stent group (group 3, n = 21), according to their type of the stent. Patency rates of each group were compared. Early stent revision was required after 3 days in 18% (4/22) of group 1, 26% (5/19) of group 2, and 0% (0/21) of group 3. The 10, 20, and 40-week primary patency rates were 77%, 77%, and 59% (group 1), 42%, 25%, and 8% (group 2), and 76%, 71%, and 55% (group 3), respectively. Primary patency rates of groups 1 and 3 were significantly higher than those of group 2 (p < 0.05), and there was no statistically difference between those of group 1 and group 3. The 10, 20, and 40-week assisted primary (secondary) patency rates were 96%, 96%, and 96% (group 1), 68%, 49%, and 39% (group 2), and 86%, 74%, and 58% (group 3), respectively. Assisted primary patency (secondary) rates of group 1 were significantly higher than those of groups 2 and 3 (p < 0.01 and p < 0.05, respectively). Our study suggests that the primary patency rates of the covered stents are equal to those of mesh stents, but these may be improved further if covered stents, which avoid the need for early revision, are used.

  15. A case of ampullary perforation treated with a temporally covered metal stent.

    PubMed

    Park, Woo Young; Cho, Kwang Bum; Kim, Eun Soo; Park, Kyung Sik

    2012-06-01

    Endoscopic retrograde cholangiopancreatography (ERCP)-related perforation is classified into three or four types based on anatomical location and the mechanism of injury. Although ampullary injury, among them, may be managed nonsurgically, surgical management is required in cases of perforation with retroperitoneal fluid collection and severe condition. Here, a patient with ERCP-related severe ampullary perforation with retroperitoneal fluid collection that was treated nonsurgically with a covered stent is presented.

  16. Direct metal transfer printing on flexible substrate for fabricating optics functional devices

    NASA Astrophysics Data System (ADS)

    Jiang, Yingjie; Zhou, Xiaohong; Zhang, Feng; Shi, Zhenwu; Chen, Linsen; Peng, Changsi

    2015-11-01

    New functional materials and devices based on metal patterns can be widely used in many new and expanding industries,such as flat panel displays, alternative energy,sensors and so on. In this paper, we introduce a new transfer printing method for fabricating metal optics functional devices. This method can directly transfer a metal pattern from a polyethylene terephthalate (PET)supported UV or polydimethylsiloxane (PDMS) pattern to another PET substrate. Purely taking advantage of the anaerobic UV curing adhesive (a-UV) on PET substrate, metal film can be easily peeled off from micro/nano-structured surface. As a result, metal film on the protrusion can be selectively transferred onto the target substrate, to make it the metal functional surface. But which on the bottom can not be transferred. This method provides low cost fabrication of metal thin film devices by avoiding high cost lithography process. Compared with conventional approach, this method can get more smooth rough edges and has wider tolerance range for the original master mold. Future developments and potential applications of this metal transfer method will be addressed.

  17. Simulation of no oxidation catalysis over oxygen-covered transition metal surfaces

    NASA Astrophysics Data System (ADS)

    Getman, Rachel B.

    Lean burn (excess O2) automobile engines are more energy efficient than their stoichiometric or rich (O2 starved) burn counterparts, but technologies do not exist to effectively remediate harmful NO x (x = 1,2) compounds from lean exhaust. Current removal strategies rely in part on the catalytic oxidation of NO to NO 2 NO+1/2O2 \\rarrr NO2 Pt is the most active metal, but there is a strong drive to use less expensive materials. Understanding how Pt functions is a key step in catalyst design. Prior experiments and theory indicate the catalysis is promoted at high O coverage (thetaO = NO/ NPt), but too much O is inhibitive: Pt is prone to oxidative deactivation. The rate is promoted by high O2 pressures and inhibited by product NO2. The latter is true even after correcting for approach to equilibrium, suggesting NO2 hinders the reaction kinetics. In this work, we attempt to understand these phenomena with molecular simulation. We use density functional theory, first principles thermodynamics, and mean field microkinetic modeling to elucidate the catalysis under actual reaction conditions. We find the reaction occurs at 0.25--0.50 monolayer O. At these thetaO, the kinetics of O2 dissociation (O2 + 2* → 2O*) are strongly inhibited due to repulsive interactions on the surface, but the O--NO bond formation (NO* + O* ⇌ NO2 + 2*) kinetics are facile. In contrast to prior reports, we show O2 dissociation is rate limiting, and O--NO bond formation is equilibrated. The rate is strongly dependent on pO2 , and the O coverage is governed by pNO2 /pNO, leading to the observed rate inhibition by NO2. These observations are in excellent agreement with experiment. We apply our models to other transition metals and transition metal alloys to facilitate new catalyst design. Analysis indicates such materials should exhibit nearly identical behavior to Pt, offering no improvements in rate or propensity to oxidize. Screening the catalytic properties of Au nanoparticles and the O

  18. CdSe Nanowire-Based Flexible Devices: Schottky Diodes, Metal-Semiconductor Field-Effect Transistors, and Inverters.

    PubMed

    Jin, Weifeng; Zhang, Kun; Gao, Zhiwei; Li, Yanping; Yao, Li; Wang, Yilun; Dai, Lun

    2015-06-24

    Novel CdSe nanowire (NW)-based flexible devices, including Schottky diodes, metal-semiconductor field-effect transistors (MESFETs), and inverters, have been fabricated and investigated. The turn-on voltage of a typical Schottky diode is about 0.7 V, and the rectification ratio is larger than 1 × 10(7). The threshold voltage, on/off current ratio, subthreshold swing, and peak transconductance of a typical MESFET are about -0.3 V, 4 × 10(5), 78 mV/dec, and 2.7 μS, respectively. The inverter, constructed with two MESFETs, exhibits clear inverting behavior with the gain to be about 28, 34, and 38, at the supply voltages (V(DD)) of 3, 5, and 7 V, respectively. The inverter also shows good dynamic behavior. The rising and falling times of the output signals are about 0.18 and 0.09 ms, respectively, under 1000 Hz square wave signals input. The performances of the flexible devices are stable and reliable under different bending conditions. Our work demonstrates these flexible NW-based Schottky diodes, MESFETs, and inverters are promising candidate components for future portable transparent nanoelectronic devices.

  19. A generalized adsorption-phase transition model to describe adsorption rates in flexible metal organic framework RPM3-Zn.

    PubMed

    Lueking, Angela D; Wang, Cheng-Yu; Sircar, Sarmishtha; Malencia, Christopher; Wang, Hao; Li, Jing

    2016-03-14

    Flexible gate-opening metal organic frameworks (GO-MOFs) expand or contract to minimize the overall free energy of the system upon accommodation of an adsorbate. The thermodynamics of the GO process are well described by a number of models, but the kinetics of the process are relatively unexplored. A flexible GO-MOF, RPM3-Zn, exhibits a significant induction period for opening by N2 and Ar at low temperatures, both above and below the GO pressure. A similar induction period is not observed for H2 or O2 at comparable pressures and temperatures, suggesting the rate of opening is strongly influenced by the gas-surface interaction rather than an external stress. The induction period leads to severe mass transfer limitations for adsorption and over-prediction of the gate-opening pressure. After review of a number of existing adsorption rate models, we find that none adequately describe the experimental rate data and similar timescales for diffusion and opening invalidate prior reaction-diffusion models. Statistically, the rate data are best described by a compressed exponential function. The resulting fitted parameters exceed the expectations for adsorption but fall within those expected for phase transition. By treating adsorption as a phase transition, we generalize the Avrami theory of phase transition kinetics to describe adsorption in both rigid and flexible hosts. The generalized theory is consistent with observed experimental trends relating to induction period, temperature, pressure, and gas-substrate interaction.

  20. Nitinol versus steel partially covered self-expandable metal stent for malignant distal biliary obstruction: a randomized trial.

    PubMed

    Soderlund, Claes; Linder, Stefan; Bergenzaun, Per E; Grape, Tomas; Hakansson, Hans-Olof; Kilander, Anders; Lindell, Gert; Ljungman, Martin; Ohlin, Bo; Nielsen, Jorgen; Rudberg, Claes; Stotzer, Per-Ove; Svartholm, Erik; Toth, Ervin; Frozanpor, Farshad

    2014-11-01

    Covered nitinol alloy self-expandable metal stents (SEMSs) have been developed to overcome the shortcomings of steel SEMS in patients with malignant biliary obstruction. In a randomized, multicenter trial, we compared stent patency, patient survival, and adverse events in patients with partly covered stents made from steel or nitinol. A total of 400 patients with unresectable distal malignant biliary obstruction were randomized at endoscopic retrograde cholangiopancreatography (ERCP) to insertion of a steel or nitinol partially covered SEMS, with 200 patients in each group. The primary outcome was confirmed stent failure during 300 days of follow-up.  At 300 days, the proportion of patients with patent stents was 77 % in the steel group, compared with 89 % in the nitinol group (P = 0.01). Confirmed stent failure occurred more often in the steel SEMS group compared with the nitinol SEMS group, in 30 versus 14 patients (P = 0.02). Stent migration occurred in 13 patients in the steel group and in 3 patients in the nitinol group (P = 0.01). Median patient survival (secondary outcome) was 137 days and 120 days in the steel SEMS and nitinol SEMS groups, respectively (P = 0.59). The nitinol SEMS showed longer patency time, and the nitinol group had fewer patients with stent failure, compared with the steel SEMS group. We could not detect any differences between the two groups regarding survival time, and regarding adverse event rate.Clinical trial registration : NCT 00980889. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Environmentally stable flexible metal-insulator-metal capacitors using zirconium-silicate and hafnium-silicate thin film composite materials as gate dielectrics.

    PubMed

    Meena, Jagan Singh; Chu, Min-Ching; Wu, Chung-Shu; Ravipati, Srikanth; Ko, Fu-Hsiang

    2011-08-01

    Fully flexible metal-insulator-metal (MIM) capacitors fabricated on 25 microm thin polyimide (PI) substrates via the surface sol-gel process using 10-nm-thick zirconium-silicate (ZrSixOy) and hafnium-silicate (HfSimOn) films as gate dielectrics. The surface morphology of the ZrSixOy and HfSimOn films were investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free surface growth had occurred on the PI. Both the films treated with oxygen (O2) plasma and annealing (ca. 250 degrees C) consisted of amorphous phase; confirmed by X-ray diffraction. We employed X-ray photoelectron spectroscopy (XPS) at high resolution to examine the chemical composition of the films subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy revealed the O2 plasma-pretreatment followed by annealing was the most effective process to the surface oxidation at relatively low-temperature, for further passivate the grease traps and making dielectric films thermally stable. The ZrSixOy and HfSimOn films in sandwich-like MIM configuration on the PI substrates exhibited the low leakage current densities of 7.1 x 10(-9) and 8.4 x 10(-9) A/cm2 at applied electric field of 10 MV/cm and maximum capacitance densities of 7.5 and 5.3 fF/microm2 at 1 MHz, respectively. In addition, the ZrSixOy and HfSimOn films in MIM capacitors showed the estimated dielectric constants of 8.2 and 6.0, respectively. Prior to use of flexible MIM capacitors in advanced flexible electronic devices; the reliability test was studied by applying day-dependent leakage current density measurements up to 30 days. These films of silicate-surfactant mesostructured materials have special interest to be used as gate dielectrics in future for flexible metal-oxide-semiconductor devices.

  2. Conformational diversity of flexible ligand in metal-organic frameworks controlled by size-matching mixed ligands

    SciTech Connect

    Hua, Xiu-Ni; Qin, Lan; Yan, Xiao-Zhi; Yu, Lei; Xie, Yi-Xin; Han, Lei

    2015-12-15

    Hydrothermal reactions of N-auxiliary flexible exo-bidentate ligand 1,3-bis(4-pyridyl)propane (bpp) and carboxylates ligands naphthalene-2,6-dicarboxylic acid (2,6-H{sub 2}ndc) or 4,4′-(hydroxymethylene)dibenzoic acid (H{sub 2}hmdb), in the presence of cadmium(II) salts have given rise to two novel metal-organic frameworks based on flexible ligands (FL-MOFs), namely, [Cd{sub 2}(2,6-ndc){sub 2}(bpp)(DMF)]·2DMF (1) and [Cd{sub 3}(hmdb){sub 3}(bpp)]·2DMF·2EtOH (2) (DMF=N,N-Dimethylformamide). Single-crystal X-ray diffraction analyses revealed that compound 1 exhibits a three-dimensional self-penetrating 6-connected framework based on dinuclear cluster second building unit. Compound 2 displays an infinite three-dimensional ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster and V-shaped organic linkers. The flexible bpp ligand displays different conformations in 1 and 2, which are successfully controlled by size-matching mixed ligands during the self-assembly process. - Graphical abstract: Compound 1 exhibits a 3D self-penetrating 6-connected framework based on dinuclear cluster, and 2 displays an infinite 3D ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster. The flexible 1,3-bis(4-pyridyl)propane ligand displays different conformations in 1 and 2, which successfully controlled by size-matching mixed ligands during the self-assembly process.

  3. Receiving Wear-Resistance Coverings Additives of Nanoparticles of Refractory Metals at a Laser Cladding

    NASA Astrophysics Data System (ADS)

    Murzakov, M. A.; Petrovskiy, V. N.; Bykovskiy, D. P.; Andreev, A. O.; Birukov, V. P.; Markushov, Y. V.

    2016-02-01

    Laser cladding technology was used to conduct experiments on production of wear-resistant coatings with additive nanoparticles of refractory metals (WC, TaC). Mechanical testing of coating abrasion was made using Brinell-Howarth method. The obtained data was compared with wear- resistance of commercial powder containing WC. It was found that at a concentration 10-15% coating with nanopowder additives shows a dramatic increase in wear-resistance by 4-6 times as compared to carbon steel substrate. There were conducted metallurgical studies of coatings on inverse electron reflection. There was determined elemental composition of deposited coating and substrate, and microhardness measured. It was found that structure of deposited coating with nanoparticles is fine.

  4. Flexibility of the metal-binding region in apo-cupredoxins

    PubMed Central

    Zaballa, María-Eugenia; Abriata, Luciano A.; Donaire, Antonio; Vila, Alejandro J.

    2012-01-01

    Protein-mediated electron transfer is an essential event in many biochemical processes. Efficient electron transfer requires the reorganization energy of the redox event to be minimized, which is ensured by the presence of rigid donor and acceptor sites. Electron transfer copper sites are present in the ubiquitous cupredoxin fold, able to bind one or two copper ions. The low reorganization energy in these metal centers has been accounted for by assuming that the protein scaffold creates an entatic/rack-induced state, which gives rise to a rigid environment by means of a preformed metal chelating site. However, this notion is incompatible with the need for an exposed metal-binding site and protein–protein interactions enabling metallochaperone-mediated assembly of the copper site. Here we report an NMR study that reveals a high degree of structural heterogeneity in the metal-binding region of the nonmetallated CuA-binding cupredoxin domain, arising from microsecond to second dynamics that are quenched upon metal binding. We also report similar dynamic features in apo-azurin, a paradigmatic blue copper protein, suggesting a general behavior. These findings reveal that the entatic/rack-induced state, governing the features of the metal center in the copper-loaded protein, does not require a preformed metal-binding site. Instead, metal binding is a major contributor to the rigidity of electron transfer copper centers. These results reconcile the seemingly contradictory requirements of a rigid, occluded center for electron transfer, and an accessible, dynamic site required for in vivo copper uptake. PMID:22645370

  5. Fabrication of low-fire-hazard flexible poly (vinyl chloride) via reutilization of heavy metal biosorbents.

    PubMed

    Pan, Ye-Tang; Wang, De-Yi

    2017-10-05

    As a naturally abundant biopolymer, chitosan is considered to be a suitable adsorbent for stannate (SnO3(2-)) in tin plating wastewater. However, mass transfer of the adsorbent and its recycling remain challenging problems. Though flexible poly(vinyl chloride) (PVC) is highly flammable due to the addition of plasticizers, the traditional flame retardant, antimony trioxide (Sb2O3), is potentially harmful. In this study, chitosan was anchored onto the surface of PVC resin to adsorb SnO3(2-) from wastewater. Thereafter, tin-doped chitosan-coated PVC resin was readily recycled and processed into a flexible PVC composite (modified fPVC). The limiting oxygen index value of the modified fPVC increased to 33.1%, and the peak heat release rate decreased to 161kW/m(2). In addition to reducing fire hazards, this approach also decreased the content of harmful hydrogen chloride gas released during the combustion of modified fPVC. Meanwhile, the tensile properties of modified fPVC were enhanced compared with those of the Sb2O3-treated sample. These results indicated the synthesis of an eco-friendly Sb2O3-free flexible PVC composite that poses a low fire hazard. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Rack-induced metal binding vs. flexibility: Met121His azurin crystal structures at different pH

    PubMed Central

    Messerschmidt, Albrecht; Prade, Lars; Kroes, Sandra J.; Sanders–Loehr, Joann; Huber, Robert; Canters, Gerard W.

    1998-01-01

    The rack-induced bonding mechanism of metals to proteins is a useful concept for explaining the generation of metal sites in electron transfer proteins, such as the blue copper proteins, that are designed for rapid electron transfer. The trigonal pyramidal structure imposed by the protein with three strong equatorial ligands (one Cys and two His) provides a favorable geometry for both cuprous and cupric oxidation states. However, the crystal structures of the Met121His mutant of azurin from Alcaligenes denitrificans at pH 6.5 (1.89- and 1.91-Å resolutions) and pH 3.5 (2.45-Å resolution) show that the preformed metal binding cavity in the protein is more flexible than expected. At high pH (6.5), the Cu site retains the same three equatorial ligands as in the wild-type azurin and adds His121 as a fourth strong ligand, creating a tetrahedral copper site geometry with a green color referred to as 1.5 type. In the low pH (3.5) structure, the protonation of His121 causes a conformational change in residues 117–123, moving His121 away from the copper. The empty coordination site is occupied by an oxygen atom of a nitrate molecule of the buffer solution. This axial ligand is coordinated less strongly, generating a distorted tetrahedral copper geometry with a blue color and spectroscopic properties of a type-1 site. These crystal structures demonstrate that blue copper proteins are flexible enough to permit a range of movement of the Cu atom along the axial direction of the trigonal pyramid. PMID:9520385

  7. Rack-induced metal binding vs. flexibility: Met121His azurin crystal structures at different pH.

    PubMed

    Messerschmidt, A; Prade, L; Kroes, S J; Sanders-Loehr, J; Huber, R; Canters, G W

    1998-03-31

    The rack-induced bonding mechanism of metals to proteins is a useful concept for explaining the generation of metal sites in electron transfer proteins, such as the blue copper proteins, that are designed for rapid electron transfer. The trigonal pyramidal structure imposed by the protein with three strong equatorial ligands (one Cys and two His) provides a favorable geometry for both cuprous and cupric oxidation states. However, the crystal structures of the Met121His mutant of azurin from Alcaligenes denitrificans at pH 6.5 (1.89- and 1.91-A resolutions) and pH 3.5 (2.45-A resolution) show that the preformed metal binding cavity in the protein is more flexible than expected. At high pH (6.5), the Cu site retains the same three equatorial ligands as in the wild-type azurin and adds His121 as a fourth strong ligand, creating a tetrahedral copper site geometry with a green color referred to as 1.5 type. In the low pH (3.5) structure, the protonation of His121 causes a conformational change in residues 117-123, moving His121 away from the copper. The empty coordination site is occupied by an oxygen atom of a nitrate molecule of the buffer solution. This axial ligand is coordinated less strongly, generating a distorted tetrahedral copper geometry with a blue color and spectroscopic properties of a type-1 site. These crystal structures demonstrate that blue copper proteins are flexible enough to permit a range of movement of the Cu atom along the axial direction of the trigonal pyramid.

  8. Flexible metal-oxide devices made by room-temperature photochemical activation of sol-gel films.

    PubMed

    Kim, Yong-Hoon; Heo, Jae-Sang; Kim, Tae-Hyeong; Park, Sungjun; Yoon, Myung-Han; Kim, Jiwan; Oh, Min Suk; Yi, Gi-Ra; Noh, Yong-Young; Park, Sung Kyu

    2012-09-06

    Amorphous metal-oxide semiconductors have emerged as potential replacements for organic and silicon materials in thin-film electronics. The high carrier mobility in the amorphous state, and excellent large-area uniformity, have extended their applications to active-matrix electronics, including displays, sensor arrays and X-ray detectors. Moreover, their solution processability and optical transparency have opened new horizons for low-cost printable and transparent electronics on plastic substrates. But metal-oxide formation by the sol-gel route requires an annealing step at relatively high temperature, which has prevented the incorporation of these materials with the polymer substrates used in high-performance flexible electronics. Here we report a general method for forming high-performance and operationally stable metal-oxide semiconductors at room temperature, by deep-ultraviolet photochemical activation of sol-gel films. Deep-ultraviolet irradiation induces efficient condensation and densification of oxide semiconducting films by photochemical activation at low temperature. This photochemical activation is applicable to numerous metal-oxide semiconductors, and the performance (in terms of transistor mobility and operational stability) of thin-film transistors fabricated by this route compares favourably with that of thin-film transistors based on thermally annealed materials. The field-effect mobilities of the photo-activated metal-oxide semiconductors are as high as 14 and 7 cm(2) V(-1) s(-1) (with an Al(2)O(3) gate insulator) on glass and polymer substrates, respectively; and seven-stage ring oscillators fabricated on polymer substrates operate with an oscillation frequency of more than 340 kHz, corresponding to a propagation delay of less than 210 nanoseconds per stage.

  9. Electrically shielded enclosure with magnetically retained removable cover

    DOEpatents

    Rivers, Craig J.; Lee, Roanne A.; Jones, Glenn E.

    1996-01-01

    Disclosed is an electrically shielded enclosure having electrical components therein and a removable electrically shielded cover over an opening in the enclosure with a magnetic securement mechanism provided to removably secure the cover to the enclosure in a manner which will provide easy access, yet also provide an electrical seal between the cover and the enclosure capable of preventing the passage of electrical radiation through the joint between the cover and the enclosure. Magnets are provided on the enclosure peripherally around the opening and facing the cover, and a ferromagnetic surface is provided on the mating surface of the cover facing the magnets, with a continuous electrical seal provided between the magnets and the ferromagnetic surface on the cover to prevent the leakage of electromagnetic radiation therethrough. In one embodiment the electrical seal includes a flexible metal casing or surface, which is attached to the enclosure and positioned between the magnets and the ferromagnetic surface on the cover, and which is sufficiently flexible to be capable of conforming to the ferromagnetic surface to provide an electrical seal between the cover and the enclosure. In another embodiment, the electrical seal includes a metal mesh associated with the enclosure and positioned between the magnets on the enclosure and the ferromagnetic surface on the cover. The metal mesh is also capable of conforming to the surface of the ferromagnetic surface to thereby provide an electrical seal between the cover and the enclosure.

  10. Large area ITO-free flexible white OLEDs with Orgacon PEDOT:PSS and printed metal shunting lines

    NASA Astrophysics Data System (ADS)

    Harkema, Stephan; Mennema, Sibe; Barink, Marco; Rooms, Harmen; Wilson, Joanne S.; van Mol, Ton; Bollen, Dirk

    2009-08-01

    We demonstrate the feasibility of white organic light-emitting diodes that exclude the transparent conductor indium-tinoxide. Instead, a highly conductive OrgaconTM PEDOT:PSS material in combination with a metal support structure is used as transparent anode and hole-injection layer. The PEDOT:PSS exhibits a conductivity of 460+/-20 S/cm and a work function of 5.35+/-0.05 eV. On ITO-free OLEDs on glass with an active area of ~6 cm2 the inclusion of 120 nm thick printed metal lines reduces the variation in brightness from 35% to 20%. The ITO-free concept based on PEDOT:PSS with printed metal structures is scaled up to large flexible OLEDs with a size of 150 cm2 on a heat-stabilized Teonex® Polyethylene Naphtalate foil. The voltage distribution across the various electrodes was verified by a finite element model, allowing a prediction of the OLED brightness and homogeneity over large areas.

  11. Flexible cofacial binuclear metal complexes derived from alpha,alpha-bis(salicylimino)-m-xylene.

    PubMed

    Maverick, Andrew W; Laxman, Ravi K; Hawkins, Mark A; Martone, Daniel P; Fronczek, Frank R

    2005-01-07

    The tetradentate Schiff-base ligand SIXH2 (alpha,alpha-bis(salicylimino)-m-xylene), prepared from salicylaldehyde and m-xylylenediamine, forms cofacial binuclear complexes with Pd and Cu. Of the two isomers possible (trans-syn and trans-anti) for M2(SIX)2, these complexes crystallize exclusively as the trans-anti isomer. In ansolvous Pd2(SIX)2, the metal-containing planes are approximately parallel, with PdPd 4.416(1) A. Pd2(SIX)2 also forms a crystalline solvate, in which the molecules adopt a more open conformation with longer metal-metal distances (5.109(1) and 5.112(1) A). The M...M distance is significantly longer in Cu2(SIX)2 (6.653(1) A), because of conformational changes in the m-xylylene moieties and substantial tetrahedral distortion about Cu.

  12. Rare-metal-free flexible counter electrodes for dye-sensitized solar-cells produced using wet processes only.

    PubMed

    Okada, Issei; Shiratori, Seimei

    2013-05-22

    Dye-sensitized solar-cells (DSCs) are cheap because they are produced using low-cost materials and simple manufacturing processes. However, the substrates of DSC counter electrodes are sputtered with a transparent conductive oxide and platinum. This involves vacuum manufacturing processes and high-cost (rare-metal) materials, and increases the costs of DSCs. In this study, we used non-rare-metal low-cost materials and simple wet processes, using combined poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) and Ag network (Ag NW) substrates. To solve the problem of Ag NW corrosion by the iodine electrolyte, we hot-pressed the Ag NW substrate and covered with a PEDOT/PSS layer as a barrier against iodine. The PEDOT/PSS layer acted as a catalyst and cells using an Ag NW covered with PEDOT/PSS generated electricity with illumination from both sides. The cell performance was improved by using a PEDOT/PSS layer containing 20 wt % TiO2 nanoparticles (NPs). The performance of the DSSC cell with an Ag NW substrate covered with a PEDOT/PSS layer containing TiO2 NPs (5.13%) was higher than that of a cell using an indium tin oxide substrate covered with the same layer (4.91%). These values are very similar to those of cells using a platinum counter electrode (5.36%). This research showed the possibility of replacing conventional high-cost counter electrodes with low-cost materials, and using only simple wet processes.

  13. Laser-assisted metal spinning for an efficient and flexible processing of challenging materials

    NASA Astrophysics Data System (ADS)

    Brummer, C.; Eck, S.; Marsoner, S.; Arntz, K.; Klocke, F.

    2016-03-01

    The demand for components made from high performance materials like titanium or nickel-based alloys as well as strain-hardening stainless steel is steadily increasing. However, conventional forming operations conducted on these materials are generally very laborious and time-consuming. This is where the limitations of metal spinning also become apparent. Using a laser to apply heat localized to the forming zone during metal spinning facilitates to enhance the formability of a material. In order to analyse the potential of the new manufacturing process, experimental investigations on laser-assisted shear forming and multi-pass metal spinning have been performed with austenitic stainless steel X5CrNi18-10, nickel-based alloy Inconel 718 and titanium grade 2. It could be demonstrated that the formability of these materials can be enhanced by laser-assistance. Besides the resulting enhancement of forming limits for metal spinning of challenging materials, the forming forces were reduced and the product quality was improved significantly.

  14. Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates.

    PubMed

    Zaretski, Aliaksandr V; Moetazedi, Herad; Kong, Casey; Sawyer, Eric J; Savagatrup, Suchol; Valle, Eduardo; O'Connor, Timothy F; Printz, Adam D; Lipomi, Darren J

    2015-01-30

    Graphene is expected to play a significant role in future technologies that span a range from consumer electronics, to devices for the conversion and storage of energy, to conformable biomedical devices for healthcare. To realize these applications, however, a low-cost method of synthesizing large areas of high-quality graphene is required. Currently, the only method to generate large-area single-layer graphene that is compatible with roll-to-roll manufacturing destroys approximately 300 kg of copper foil (thickness = 25 μm) for every 1 g of graphene produced. This paper describes a new environmentally benign and scalable process of transferring graphene to flexible substrates. The process is based on the preferential adhesion of certain thin metallic films to graphene; separation of the graphene from the catalytic copper foil is followed by lamination to a flexible target substrate in a process that is compatible with roll-to-roll manufacturing. The copper substrate is indefinitely reusable and the method is substantially greener than the current process that uses relatively large amounts of corrosive etchants to remove the copper. The sheet resistance of the graphene produced by this new process is unoptimized but should be comparable in principle to that produced by the standard method, given the defects observable by Raman spectroscopy and the presence of process-induced cracks. With further improvements, this green, inexpensive synthesis of single-layer graphene could enable applications in flexible, stretchable, and disposable electronics, low-profile and lightweight barrier materials, and in large-area displays and photovoltaic modules.

  15. Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates

    NASA Astrophysics Data System (ADS)

    Zaretski, Aliaksandr V.; Moetazedi, Herad; Kong, Casey; Sawyer, Eric J.; Savagatrup, Suchol; Valle, Eduardo; O'Connor, Timothy F.; Printz, Adam D.; Lipomi, Darren J.

    2015-01-01

    Graphene is expected to play a significant role in future technologies that span a range from consumer electronics, to devices for the conversion and storage of energy, to conformable biomedical devices for healthcare. To realize these applications, however, a low-cost method of synthesizing large areas of high-quality graphene is required. Currently, the only method to generate large-area single-layer graphene that is compatible with roll-to-roll manufacturing destroys approximately 300 kg of copper foil (thickness = 25 μm) for every 1 g of graphene produced. This paper describes a new environmentally benign and scalable process of transferring graphene to flexible substrates. The process is based on the preferential adhesion of certain thin metallic films to graphene; separation of the graphene from the catalytic copper foil is followed by lamination to a flexible target substrate in a process that is compatible with roll-to-roll manufacturing. The copper substrate is indefinitely reusable and the method is substantially greener than the current process that uses relatively large amounts of corrosive etchants to remove the copper. The sheet resistance of the graphene produced by this new process is unoptimized but should be comparable in principle to that produced by the standard method, given the defects observable by Raman spectroscopy and the presence of process-induced cracks. With further improvements, this green, inexpensive synthesis of single-layer graphene could enable applications in flexible, stretchable, and disposable electronics, low-profile and lightweight barrier materials, and in large-area displays and photovoltaic modules.

  16. Construction of flexible metal-organic framework (MOF) papers through MOF growth on filter paper and their selective dye capture.

    PubMed

    Park, Jeehyun; Oh, Moonhyun

    2017-09-14

    The conjugation of metal-organic frameworks (MOFs) with other materials is an excellent strategy for the production of advanced materials having desired properties and so appropriate applicability. In particular, the integration of MOFs with a flexible paper is expected to form valuable materials in separation technology. Here we report a simple method for the generation of MOF papers through the compact and uniform growth of MOF nanoparticles on the cellulose surface of a carboxymethylated filter paper. The resulting MOF papers show a selective capture ability for negatively charged organic dyes and they can be used for dye separation through simple filtration of a dye solution on the MOF papers. In addition, MOF papers can be reused after a simple washing process without losing their effective dye capture ability.

  17. Bending stability of GaN grown on a metallic flexible substrate by plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Rodríguez, A. G.; Chávez-Veloz, S. G.; Compeán-García, V. D.; López-Luna, E.; Vidal, M. A.

    2017-08-01

    GaN thin films were grown on flexible metallic substrates by molecular beam epitaxy. MgO buffer layers were deposited by spin coating on Ni-Mo-Cr (Hastelloy C-276) alloy tapes that were used as substrates. The structural characterization of the GaN/MgO/hastelloy samples was performed by x-ray diffraction and Raman spectroscopy. The obtained nanometric films have the stable hexagonal phase (α-GaN) with an average crystallite size of 18 nm. The long and short range order of GaN decrease when the structure is bent. The most significant variations in the structural properties occur between 100 and 250 bending cycles.

  18. Strain-induced reversible modulation of the magnetic anisotropy in perpendicularly magnetized metals deposited on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Ota, Shinya; Hibino, Yuki; Bang, Do; Awano, Hiroyuki; Kozeki, Takahiro; Akamine, Hirokazu; Fujii, Tatsuya; Namazu, Takahiro; Takenobu, Taishi; Koyama, Tomohiro; Chiba, Daichi

    2016-04-01

    In this study, the strain-induced change in the magnetic anisotropy of perpendicularly magnetized thin metals (TbFeCo and Pt/Co/Pt) deposited on a polyethylene naphthalate flexible substrate was investigated. The in-plane uniaxial tensile strain was reversibly applied up to 2%. The magnetic anisotropy was reversibly changed in both samples with applied stress. In the TbFeCo film, a marked change in magnetic anisotropy energy of 1.2 × 105 J/m3 was observed. In the Pt/Co/Pt film, where the thickness of Co was 2-4 monolayers, the stress-induced changes in interface and volume contributions to magnetic anisotropy were individually determined.

  19. Design and Development of Expanded Graphite-Based Non-metallic and Flexible Metamaterial Absorber for X-band Applications

    NASA Astrophysics Data System (ADS)

    Borah, Dipangkar; Bhattacharyya, Nidhi S.

    2017-01-01

    The possibility of using expanded graphite instead of a metallic layer as unit cells and ground planes for metamaterial absorbers in X-band is investigated. A metamaterial absorber was fabricated on a flexible linear low-density polyethylene substrate using an expanded graphite-based circular ring as the unit cell structure. The unit cell was simulated and optimized for which the metamaterial absorber exhibited 98.9% absorption at 11.22 GHz. The fabricated expanded graphite-based absorber showed a reflection loss of -24.51 dB at 11.56 GHz with -10 dB bandwidth of 0.39 GHz (3.37%). The performance of the same structure with copper was also measured. The expanded graphite-based metamaterial absorber showed enhanced performance as compared to the copper-based metamaterial absorber. The width of the ring was varied to tune the reflection loss. The proposed expanded graphite-based metamaterial absorber possesses the advantages of being ultra-thin, flexible and non-corrosive.

  20. Construction of a polyhedral metal-organic framework via a flexible octacarboxylate ligand for gas adsorption and separation.

    PubMed

    Lin, Zu-Jin; Huang, Yuan-Biao; Liu, Tian-Fu; Li, Xiang-Ying; Cao, Rong

    2013-03-18

    A flexible octacarboxylate ligand, tetrakis[(3,5-dicarboxyphenyl)oxamethyl]methane (H8X), has been used to construct a highly porous metal-organic framework (In2X)(Me2NH2)2(DMF)9(H2O)5 (1), which is comprised of octahedral and cuboctahedral cages and shows a rare (4,8)-connected scu topology. Gas adsorption studies of N2, H2 on the actived 1 at 77 K reveal a Langmuir surface area of 1707 m(2) g(-1), a BET surface area of 1555 m(2) g(-1), a total pore volume of 0.62 cm(3) g(-1), and a H2 uptake of 1.49 wt % at 1 bar and 3.05 wt % at 16 bar. CO2, CH4, and N2 adsorption studies at 195, 273, 285, and 298 K and also ideal adsorbed solution theory (IAST) calculations demonstrate that 1 has high selectivites of CO2 over CH4 and N2. The resulting framework represents a MOF with the highest gas uptakes and gas selectivities (CO2 over CH4 and N2) constructed by flexible ligands.

  1. Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution: A Randomized Clinical Trial.

    PubMed

    Coté, Gregory A; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K; Elmunzer, B Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

    Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of -15%. There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, -3.0% to ∞; P < .001). Given the prespecified noninferiority margin of -15%, the null hypothesis that cSEMS is less effective than plastic stents was rejected. The

  2. Metal Ion Dependence, Thermodynamics, and Kinetics for Intramolecular Docking of a GAAA Tetraloop and Receptor Connected by a Flexible Linker†

    PubMed Central

    Downey, Christopher D.; Fiore, Julie L.; Stoddard, Colby D.; Hodak, Jose H.; Nesbitt, David J.; Pardi, Arthur

    2008-01-01

    The GAAA tetraloop-receptor is a commonly occurring tertiary interaction motif in RNA. This motif usually occurs in combination with other tertiary interactions in complex RNA structures. Thus, it is difficult to measure directly the contribution that a single GAAA tetraloop-receptor interaction makes to the folding properties of an RNA. To investigate the kinetics and thermodynamics for the isolated interaction, a GAAA tetraloop domain and receptor domain were connected by a single-stranded A7 linker. Fluorescence resonance energy transfer (FRET) experiments were used to probe intramolecular docking of the GAAA tetraloop and receptor. Docking was induced using a variety of metal ions, where the charge of the ion was the most important factor in determining the concentration of the ion required to promote docking ([Co(NH3)63+] ≪ [Ca2+], [Mg2+], [Mn2+] ≪ [Na+], [K+]). Analysis of metal ion cooperativity yielded Hill coefficients of ≈ 2 for Na+- or K+-dependent docking versus ≈ 1 for the divalent ions and Co(NH3)63+. Ensemble stopped-flow FRET kinetic measurements yielded an apparent activation energy of 12.7 kcal/mol for GAAA tetraloop-receptor docking. RNA constructs with U7 and A14 single-stranded linkers were investigated by single-molecule and ensemble FRET techniques to determine how linker length and composition affect docking. These studies showed that the single-stranded region functions primarily as a flexible tether. Inhibition of docking by oligonucleotides complementary to the linker was also investigated. The influence of flexible versus rigid linkers on GAAA tetraloop-receptor docking is discussed. PMID:16533049

  3. Fabrication of a silver particle-integrated silicone polymer-covered metal stent against sludge and biofilm formation and stent-induced tissue inflammation

    PubMed Central

    Lee, Tae Hoon; Jang, Bong Seok; Jung, Min Kyo; Pack, Chan Gi; Choi, Jun-Ho; Park, Do Hyun

    2016-01-01

    To reduce tissue or tumor ingrowth, covered self-expandable metal stents (SEMSs) have been developed. The effectiveness of covered SEMSs may be attenuated by sludge or stone formation or by stent clogging due to the formation of biofilm on the covering membrane. In this study, we tested the hypothesis that a silicone membrane containing silver particles (Ag-P) would prevent sludge and biofilm formation on the covered SEMS. In vitro, the Ag-P-integrated silicone polymer-covered membrane exhibited sustained antibacterial activity, and there was no definite release of silver ions from the Ag-P-integrated silicone polymer membrane at any time point. Using a porcine stent model, in vivo analysis demonstrated that the Ag-P-integrated silicone polymer-covered SEMS reduced the thickness of the biofilm and the quantity of sludge formed, compared with a conventional silicone-covered SEMS. In vivo, the release of silver ions from an Ag-P-integrated silicone polymer-covered SEMS was not detected in porcine serum. The Ag-P-integrated silicone polymer-covered SEMS also resulted in significantly less stent-related bile duct and subepithelium tissue inflammation than a conventional silicone polymer-covered SEMS. Therefore, the Ag-P-integrated silicone polymer-covered SEMS reduced sludge and biofilm formation and stent-induced pathological changes in tissue. This novel SEMS may prolong the stent patency in clinical application. PMID:27739486

  4. Experimental Studies on Flexible Forming of Sheet Metals Assisted by Magnetic Force Transfer Medium

    NASA Astrophysics Data System (ADS)

    Li, Feng; Zhou, Fu Jian; Wang, Mo Nan; Xu, Peng; Jin, Cheng Chuang

    2016-08-01

    To improve the thickness uniformity and increase the forming limit of sheets to enhance their overall quality, a magnetorheological fluid (MRF) was injected into the punch cavity to act as the force transfer medium and fulfill the function of flexible pressing during the sheet bulging process. The rheological properties of the MRF were changed under the influence of a magnetic field produced by loading different currents, which allowed variation of stress states and deformation modes in the 0.75-mm-thick 304 stainless steel sheets. With increasing current (up to 3.5 A), the sheet-forming limit increased by 16.13% at most, and the fracture morphology experienced a certain change. Additionally, both the bulge height and the wall thickness distribution had obvious changes with a punch stroke of 10 mm. According to the experimental analysis, the MRF can be used successfully as a pressure-carrying medium in the sheet forming process.

  5. Hierarchical graphene/metal grid structures for stable, flexible transparent conductors.

    PubMed

    Gao, Tongchuan; Li, Zhiting; Huang, Po-shun; Shenoy, Ganesh J; Parobek, David; Tan, Susheng; Lee, Jung-kun; Liu, Haitao; Leu, Paul W

    2015-05-26

    We report an experimental study on the fabrication and characterization of hierarchical graphene/metal grid structures for transparent conductors. The hierarchical structure allows for uniform and local current conductivity due to the graphene and exhibits low sheet resistance because the microscale silver grid serves as a conductive backbone. Our samples demonstrate 94% diffusive transmission with a sheet resistance of 0.6 Ω/sq and a direct current to optical conductivity ratio σdc/σop of 8900. The sheet resistance of the hierarchical structure may be improved by over 3 orders of magnitude and with little decrease in transmission compared with graphene. Furthermore, the graphene protects the silver grid from thermal oxidation and better maintains the sheet resistance of the structure at elevated temperature. The graphene also strengthens the adhesion of the metal grid with the substrate such that the structure is more resilient under repeated bending.

  6. Flexible, Luminescent Metal-Organic Frameworks Showing Synergistic Solid-Solution Effects on Porosity and Sensitivity.

    PubMed

    Liu, Si-Yang; Zhou, Dong-Dong; He, Chun-Ting; Liao, Pei-Qin; Cheng, Xiao-Ning; Xu, Yan-Tong; Ye, Jia-Wen; Zhang, Jie-Peng; Chen, Xiao-Ming

    2016-12-23

    Mixing molecular building blocks in the solid solution manner is a valuable strategy to obtain structures and properties in between the isostructural parent metal-organic frameworks (MOFs). We report nonlinear/synergistic solid-solution effects using highly related yet non-isostructural, phosphorescent Cu(I) triazolate frameworks as parent phases. Near the phase boundaries associated with conformational diversity and ligand heterogeneity, the porosity (+150 %) and optical O2 sensitivity (410 times, limit of detection 0.07 ppm) can be drastically improved from the best-performing parent MOFs and even exceeds the records hold by precious-metal complexes (3 ppm) and C70 (0.2 ppm).

  7. Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water

    DTIC Science & Technology

    2016-10-01

    Pollutant Discharge Elimination System NTU Nephelometric Turbidity Unit SAFR Small Arms Firing Range SDWA Safe Drinking Water Act SEL Severe Effect...metalloids, and metals bound to the suspended solids. The filter sock is National Pollutant Discharge Elimination System (NPDES)-approved for use on...into a tubular shape (“filter sock”) and filled with sand (Figure 1). The filter sock is National Pollutant Discharge Elimination System (NPDES

  8. Comparison of the utility of covered metal stents versus uncovered metal stents in the management of malignant biliary strictures in 749 patients.

    PubMed

    Lee, Jeffrey H; Krishna, Somashekar G; Singh, Amanpal; Ladha, Harshad S; Slack, Rebecca S; Ramireddy, Srinivas; Raju, Gottumukkala S; Davila, Marta; Ross, William A

    2013-08-01

    Self-expandable metal stents (SEMSs) are used to relieve malignant biliary obstruction. To compare outcomes between covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (USEMSs) in malignant biliary obstruction. Retrospective cohort study. Tertiary cancer center. Patients with malignant biliary obstruction. Placement of CSEMS or USEMS. Time to recurrent biliary obstruction (TRO), overall survival (OS), and adverse events. From January 2000 to June 2011, 749 patients received SEMSs: 171 CSEMSs and 578 USEMSs. At 1 year, there was no significant difference in the percentage of patients with recurrent obstruction (CSEMSs, 35% vs USEMSs, 38%) and survival (CSEMSs, 45% vs USEMSs, 49%). There was no significant difference in the median OS (CSEMSs, 10.4 months vs USEMSs, 11.8 months; P = .84) and the median TRO (CSEMSs, 15.4 months vs USEMSs, 26.3 months; P = .61). The adverse event rate was 27.5% for the CSEMS group and 27.7% for the USEMS group. Although tumor ingrowth with recurrent obstruction was more common in the USEMS group (76% vs 9%, P < .001), stent migration (36% vs 2%, P < .001) and acute pancreatitis (6% vs 1%, P < .001) were more common in the CSEMS group. Retrospective study. There was no significant difference in the patency rate or overall survival between CSEMSs and USEMSs for malignant distal biliary strictures. The CSEMS group had a significantly higher rate of migration and pancreatitis than the USEMS group. No significant SEMS-related adverse events were observed in patients undergoing neoadjuvant chemoradiation or surgical resection. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  9. Extremely robust and conformable capacitive pressure sensors based on flexible polyurethane foams and stretchable metallization

    NASA Astrophysics Data System (ADS)

    Vandeparre, H.; Watson, D.; Lacour, S. P.

    2013-11-01

    Microfabricated capacitive sensors prepared with elastomeric foam dielectric films and stretchable metallic electrodes display robustness to extreme conditions including stretching and tissue-like folding and autoclaving. The open cellular structure of the elastomeric foam leads to significant increase of the capacitance upon compression of the dielectric membrane. The sensor sensitivity can be adjusted locally with the foam density to detect normal pressure in the 1 kPa to 100 kPa range. Such pressure transducers will find applications in interfaces between the body and support surfaces such as mattresses, joysticks or prosthetic sockets, in artificial skins and wearable robotics.

  10. A randomized trial comparing uncovered and partially covered self-expandable metal stents in the palliation of distal malignant biliary obstruction.

    PubMed

    Telford, Jennifer J; Carr-Locke, David L; Baron, Todd H; Poneros, John M; Bounds, Brenna C; Kelsey, Peter B; Schapiro, Robert H; Huang, Christopher S; Lichtenstein, David R; Jacobson, Brian C; Saltzman, John R; Thompson, Christopher C; Forcione, David G; Gostout, Christopher J; Brugge, William R

    2010-11-01

    The most common complication of uncovered biliary self-expandable metal stents (SEMSs) is tumor ingrowth. The addition of an impenetrable covering may prolong stent patency. To compare stent patency between uncovered and partially covered SEMSs in malignant biliary obstruction. Multicenter randomized trial. Four teaching hospitals. Adults with inoperable distal malignant biliary obstruction. Uncovered or partially covered SEMS insertion. Time to recurrent biliary obstruction, patient survival, serious adverse events, and mechanism of recurrent biliary obstruction. From October 2002 to May 2008, 129 patients were randomized. Recurrent biliary obstruction was observed in 11 of 61 uncovered SEMSs (18%) and 20 of 68 partially covered SEMSs (29%). The median times to recurrent biliary obstruction were 711 days and 357 days for the uncovered and partially covered SEMS groups, respectively (P = .530). Median patient survival was 239 days for the uncovered SEMS and 227 days for the partially covered SEMS groups (P = .997). Serious adverse events occurred in 27 (44%) and 42 (62%) patients in the uncovered and partially covered SEMS groups, respectively (P = .046). None of the uncovered and 8 (12%) of the partially covered SEMSs migrated (P = .0061). Intended sample size was not reached. Allocation to treatment groups was unequal. There was no significant difference in time to recurrent biliary obstruction or patient survival between the partially covered and uncovered SEMS groups. Partially covered SEMSs were associated with more serious adverse events, particularly migration. Copyright © 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  11. Characteristic Improvements of ZnO-Based Metal-Semiconductor-Metal Photodetector on Flexible Substrate with ZnO Cap Layer

    NASA Astrophysics Data System (ADS)

    Ji, Liang-Wen; Wu, Cheng-Zhi; Lin, Chih-Ming; Meen, Teen-Hang; Lam, Kin-Tak; Peng, Shi-Ming; Young, Sheng-Joue; Liu, Chien-Hung

    2010-05-01

    In this work, ZnO-based metal-semiconductor-metal photodetectors with and without a ZnO cap layer were fabricated on flexible substrates of poly(ethylene terephthalate) (PET) for comparative analysis. The ZnO films were prepared by a low-temperature sputtering process. The photodetector with a ZnO cap layer (stack structure: ZnO/Ag/ZnO/PET) shows a much higher UV-to-visible rejection ratio of 1.56 ×103 than that without. This can be attributed to the photocurrents that are not only significantly increased in the UV region but also slightly suppressed in the visible region for such a novel structure. With an incident wavelength of 370 nm and an applied bias of 3 V, the responsivities of both photodetectors with and without a ZnO cap layer are 3.80 ×10-2 and 2.36 ×10-3 A/W, which correspond to quantum efficiencies of 1.13 and 0.07%, respectively. The Schottky barrier height at the Ag/ZnO interface is also determined to be 0.782 eV.

  12. Characteristic Improvements of ZnO-Based Metal-Semiconductor-Metal Photodetector on Flexible Substrate with ZnO Cap Layer

    NASA Astrophysics Data System (ADS)

    Liang-Wen Ji,; Cheng-Zhi Wu,; Chih-Ming Lin,; Teen-Hang Meen,; Kin-Tak Lam,; Shi-Ming Peng,; Sheng-Joue Young,; Chien-Hung Liu,

    2010-05-01

    In this work, ZnO-based metal-semiconductor-metal photodetectors with and without a ZnO cap layer were fabricated on flexible substrates of poly(ethylene terephthalate) (PET) for comparative analysis. The ZnO films were prepared by a low-temperature sputtering process. The photodetector with a ZnO cap layer (stack structure: ZnO/Ag/ZnO/PET) shows a much higher UV-to-visible rejection ratio of 1.56 × 103 than that without. This can be attributed to the photocurrents that are not only significantly increased in the UV region but also slightly suppressed in the visible region for such a novel structure. With an incident wavelength of 370 nm and an applied bias of 3 V, the responsivities of both photodetectors with and without a ZnO cap layer are 3.80 × 10-2 and 2.36 × 10-3 A/W, which correspond to quantum efficiencies of 1.13 and 0.07%, respectively. The Schottky barrier height at the Ag/ZnO interface is also determined to be 0.782 eV.

  13. Efficacy and safety of a new fully covered self-expandable non-foreshortening metal esophageal stent.

    PubMed

    Dua, Kulwinder S; Latif, Sahibzada U; Yang, Juliana F; Fang, Tom C; Khan, Abdul; Oh, Young

    2014-10-01

    Fully covered esophageal self-expandable metal stents (SEMSs) are potentially removable but can be associated with high migration rates. For precise positioning, non-foreshortening SEMSs are preferred. Recently, a new fully covered non-foreshortening SEMS with anti-migration features was introduced. To evaluate the efficacy and safety of this new esophageal SEMS. Retrospective study. Single, tertiary-care center. Consecutive patients with malignant and benign strictures with dysphagia grade of ≥3 and patients with fistulas/leaks were studied. Stent placement and removal. Technical success in stent deployment/removal, efficacy in relieving dysphagia and sealing fistulas/leaks, and adverse events. Forty-three stents were placed in 35 patients (mean [± standard deviation] age 65 ± 11 years; 31 male), 24 for malignant and 11 for benign (5 strictures, 6 leaks) indications. Technical success in precise SEMS placement was 100%. The after-stent dysphagia grade improved significantly (at 1 week: 1.5 ± 0.7; at 4 weeks: 1.2 ± 0.4; baseline: 3.8 ± 0.4; P < .0001). Twenty stents were removed for clinical indications, with technical success of 100%. All leaks sealed after SEMS placement and did not recur after stent removal. All benign strictures recurred after stent removal. Adverse events included migration (14%), chest pain (11%), and dysphagia from tissue hyperplasia (6%). There was no stent-related mortality. Nonrandomized, single-center study. The new esophageal SEMS was effective in relieving malignant dysphagia, allowed for precise placement, and was easily removable. It was effective in treating benign esophageal fistulas and leaks. Stent-related adverse events were acceptable. Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  14. Self-assembled large scale metal alloy grid patterns as flexible transparent conductive layers

    PubMed Central

    Mohl, Melinda; Dombovari, Aron; Vajtai, Robert; Ajayan, Pulickel M.; Kordas, Krisztian

    2015-01-01

    The development of scalable synthesis techniques for optically transparent, electrically conductive coatings is in great demand due to the constantly increasing market price and limited resources of indium for indium tin oxide (ITO) materials currently applied in most of the optoelectronic devices. This work pioneers the scalable synthesis of transparent conductive films (TCFs) by exploiting the coffee-ring effect deposition coupled with reactive inkjet printing and subsequent chemical copper plating. Here we report two different promising alternatives to replace ITO, palladium-copper (PdCu) grid patterns and silver-copper (AgCu) fish scale like structures printed on flexible poly(ethylene terephthalate) (PET) substrates, achieving sheet resistance values as low as 8.1 and 4.9 Ω/sq, with corresponding optical transmittance of 79% and 65% at 500 nm, respectively. Both films show excellent adhesion and also preserve their structural integrity and good contact with the substrate for severe bending showing less than 4% decrease of conductivity even after 105 cycles. Transparent conductive films for capacitive touch screens and pixels of microscopic resistive electrodes are demonstrated. PMID:26333520

  15. Self-assembled large scale metal alloy grid patterns as flexible transparent conductive layers.

    PubMed

    Mohl, Melinda; Dombovari, Aron; Vajtai, Robert; Ajayan, Pulickel M; Kordas, Krisztian

    2015-09-03

    The development of scalable synthesis techniques for optically transparent, electrically conductive coatings is in great demand due to the constantly increasing market price and limited resources of indium for indium tin oxide (ITO) materials currently applied in most of the optoelectronic devices. This work pioneers the scalable synthesis of transparent conductive films (TCFs) by exploiting the coffee-ring effect deposition coupled with reactive inkjet printing and subsequent chemical copper plating. Here we report two different promising alternatives to replace ITO, palladium-copper (PdCu) grid patterns and silver-copper (AgCu) fish scale like structures printed on flexible poly(ethylene terephthalate) (PET) substrates, achieving sheet resistance values as low as 8.1 and 4.9 Ω/sq, with corresponding optical transmittance of 79% and 65% at 500 nm, respectively. Both films show excellent adhesion and also preserve their structural integrity and good contact with the substrate for severe bending showing less than 4% decrease of conductivity even after 10(5) cycles. Transparent conductive films for capacitive touch screens and pixels of microscopic resistive electrodes are demonstrated.

  16. Flexible heterostructures based on metal phthalocyanines thin films obtained by MAPLE

    NASA Astrophysics Data System (ADS)

    Socol, M.; Preda, N.; Rasoga, O.; Breazu, C.; Stavarache, I.; Stanculescu, F.; Socol, G.; Gherendi, F.; Grumezescu, V.; Popescu-Pelin, G.; Girtan, M.; Stefan, N.

    2016-06-01

    Heterostructures based on zinc phthalocyanine (ZnPc), magnesium phthalocyanine (MgPc) and 5,10,15,20-tetra(4-pyrydil)21H,23H-porphine (TPyP) were deposited on ITO flexible substrates by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. Organic heterostructures containing (TPyP/ZnPc(MgPc)) stacked or (ZnPc(MgPc):TPyP) mixed layers were characterized by X-ray diffraction-XRD, photoluminescence-PL, UV-vis and FTIR spectroscopy. No chemical decomposition of the initial materials was observed. The investigated structures present a large spectral absorption in the visible range making them suitable for organic photovoltaics applications (OPV). Scanning electron microscopy-SEM and atomic force microscopy-AFM revealed morphologies typical for the films prepared by MAPLE. The current-voltage characteristics of the investigated structures, measured in dark and under light, present an improvement in the current value (∼3 order of magnitude larger) for the structure based on the mixed layer (Al/MgPc:TPyP/ITO) in comparison with the stacked layer (Al/MgPc//TPyP/ITO). A photogeneration process was evidenced in the case of structures Al/ZnPc:TPyP/ITO with mixed layers.

  17. Self-assembled large scale metal alloy grid patterns as flexible transparent conductive layers

    NASA Astrophysics Data System (ADS)

    Mohl, Melinda; Dombovari, Aron; Vajtai, Robert; Ajayan, Pulickel M.; Kordas, Krisztian

    2015-09-01

    The development of scalable synthesis techniques for optically transparent, electrically conductive coatings is in great demand due to the constantly increasing market price and limited resources of indium for indium tin oxide (ITO) materials currently applied in most of the optoelectronic devices. This work pioneers the scalable synthesis of transparent conductive films (TCFs) by exploiting the coffee-ring effect deposition coupled with reactive inkjet printing and subsequent chemical copper plating. Here we report two different promising alternatives to replace ITO, palladium-copper (PdCu) grid patterns and silver-copper (AgCu) fish scale like structures printed on flexible poly(ethylene terephthalate) (PET) substrates, achieving sheet resistance values as low as 8.1 and 4.9 Ω/sq, with corresponding optical transmittance of 79% and 65% at 500 nm, respectively. Both films show excellent adhesion and also preserve their structural integrity and good contact with the substrate for severe bending showing less than 4% decrease of conductivity even after 105 cycles. Transparent conductive films for capacitive touch screens and pixels of microscopic resistive electrodes are demonstrated.

  18. Flexible metallic ultrasonic transducers for structural health monitoring of pipes at high temperatures.

    PubMed

    Shih, Jeanne-Louise; Kobayashi, Makiko; Jen, Cheng-Kuei

    2010-09-01

    Piezoelectric films have been deposited by a sol-gel spray technique onto 75-μm-thick titanium and stainless steel (SS) membranes and have been fabricated into flexible ultrasonic transducers (FUTs). FUTs using titanium membranes were glued and those using SS membranes brazed onto steel pipes, procedures that serve as on-site installation techniques for the purpose of offering continuous thickness monitoring capabilities at up to 490 °C. At 150 °C, the thickness measurement accuracy of a pipe with an outer diameter of 26.6 mm and a wall thickness of 2.5 mm was estimated to be 26 μm and the center frequency of the FUT was 10.8 MHz. It is demonstrated that the frequency bandwidth of the FUTs and SNR of signals using glue or brazing materials as high-temperature couplant for FUTs are sufficient to inspect the steel pipes even with a 2.5 mm wall thickness.

  19. Flexible ultrasonic transducers for structural health monitoring of metals and composites

    NASA Astrophysics Data System (ADS)

    Kobayashi, M.; Wu, K.-T.; Shih, J.-L.; Jen, C.-K.; Kruger, S. E.

    2010-03-01

    Flexible ultrasonic transducers (FUTs) which have the on-site installation capability are presented for the non-destructive evaluation (NDE) and structural health monitoring (SHM) purposes. These FUTs consist of 75 μm thick titanium membrane, thick (> 70 μm) thick piezoelectric lead-zirconate-titanate (PZT) composite (PZT-c) films and thin (< 5 μm) thick top electrodes. The PZT-c films are made by a sol-gel spray technique. Such FUT has been glued onto a steel pipe of 101 mm in diameter and 4.5 mm in wall thickness and operated up to 200°C. The glue served as high temperature ultrasonic couplant between the FUT and the external surface of the pipe. The estimated pipe thickness measurement accuracy at 200°C is 34 μm. FUTs also were glued onto the end edge of 2 mm thick aluminum (Al) plates to generate and receive predominantly symmetrical and shear-horizontal (SH) plate acoustic waves (PAWs) to detect simulated line defects at temperature up to 100°C. FUTs glued onto a graphite/epoxy (Gr/Ep) composite are also used for the detection of artificial disbonds. An induction type non-contact method for the evaluation of Al plates and Gr/Ep composites using FUTs is also demonstrated.

  20. [Flexible metallic intramedullary nail, an ideal osteosynthesis material for femoral fractions].

    PubMed

    Firică, A; Mucichescu, D; Troianescu, O; Răzuş, M

    1977-01-01

    The authors have used modified Ender nails for the treatment of femural fractures. Nails of different sizes are used in different arrangements, depending on the site of the lesion. Thus, for fractures of the femural neck 3 metallic nails, with a diameter of 4 mm are used, introduced through the internal supra-condylian aspect in paralel arcs; two nails, 5 mm in diameter, are introduced in the same way for the correction of the fractures involving the trochanterian massif; for fractures sited under the trochanterian massif (diaphysis, supracondylian, and supra- and inter-condylian), 5 mm diameter nails are used, placed on the internal and external aspects of the condyl in metalic arcs. This type of intervention was demonstrated to be stable, rapid, non-haemorrhagic and with low risk of shock. Supported walking is started in the first week after surgery--in cases with fractures of the trochanterian massif and of the diaphysis--provided these are stable fractures, in the first month when unstable fractures occur at the same level, and after 3--4 months in cases of fractures of the cervical neck. The authors' experience in the treatment of 250 cases is presented.

  1. Metal Covering of Airplanes

    NASA Technical Reports Server (NTRS)

    Mathar, J

    1930-01-01

    This paper presents a relative determination of the wrinkling of a plate wall beam with variable number of supports and methods of attachment. The discussion is based entirely on tests with extensometer readings and number of wrinkles, with complete web and with cutout sections. The author notes that the number of corrugations increase with added stress, keeping constant edge spacing.

  2. Biliary stenting is not a prerequisite to endoscopic placement of duodenal covered self-expandable metal stents.

    PubMed

    Poincloux, L; Goutorbe, F; Rouquette, O; Mulliez, A; Goutte, M; Bommelaer, G; Abergel, A

    2016-02-01

    Duodenal covered self-expandable metal stent (cSEMS) can be used in malignant or benign gastroduodenal obstruction. The need for biliary stenting in patients with no concomitant biliary stricture, before duodenal cSEMS placement, remains unknown. The aim of this study was to determine whether cSEMS placement is responsible for biliary obstruction. This is a single-center, retrospective, case-controlled study, including 106 patients with symptomatic gastric outlet obstruction or duodenal fistula who received a covered nitinol duodenal stent by using through-the-scope/over-the-wire placement procedure. The main outcome measurement was the occurrence comparison of jaundice and bilirubin level, between patients with previous or concomitant biliary stenting (cSEMS + BS group), and patients with no biliary stent (cSEMS group) during an observational period of 90 days. Hundred and six patients underwent cSEMS placement between June 2005 and March 2014: 53 in the cSEMS group (58% male, mean age 66.4 ± 13.3 years) and 53 in cSEMS + BS group (60% male, mean age 70.4 ± 11.6 years). The obstruction was due to cancer in 45% in cSEMS group and 87% in cSEMS + BS group. No case of jaundice was reported in the cSEMS group or in the cSEMS + BS group. In cSEMS group, the mean bilirubin level (μmol/L ± SD) was 8.0 ± 4 at baseline and 8.5 ± 4.6 at day 10, while in the cSEMS + BS group it was 91.4 ± 108 at baseline and 35.3 ± 39 at day 10 (p < 0.01). Patients from the two groups were matched on age, gender and bilirubin level at baseline. Evolution of bilirubinemia was +0.98 ± 2.76 µmol/L in experimental group and +0.39 ± 522 µmol/L in the control group (p = 0.34). No significant difference was observed between the two groups in term of technical success, clinical effectiveness, migration and other complications. Previous biliary stenting is not required before endoscopic covered duodenal stent placement in patients with no associated biliary obstruction. Prospective studies

  3. Combined Placement of Covered Self-Expanding Metallic Stents and Nasojejunal Tube for Managing Large Lower Esophageal Perforations.

    PubMed

    Rana, Surinder S; Gupta, Rajesh; Dahiya, Divya; Behera, Arunanshu; Bhasin, Deepak K

    2014-02-01

    Covered self-expanding metallic stents (cSEMSs) have emerged as effective treatment option for esophageal perforations. However, the large lower esophageal perforations where the cSEMS is placed across gastroesophageal junction have lower healing rates because refluxed gastric contents constantly irritate perforation and also there is increased risk of stent migration. Moreover, gastric mucosa tends to prolapse into lumen of lower end of stent causing its obstruction, leading to seepage of saliva and fluids from upper end of stent even in the patients who are on parenteral nutrition. We present our experience of a novel technique of combined cSEMS and nasojejunal tube (NJT) placement in four patients (two males) with benign large lower esophageal perforations. The NJT was placed through the stent into the jejunum through which patients were given enteral feeding. The stents were placed 5 - 21 days after esophageal perforation with the size of perforation ranging from 4 to 6 cm. As the NJT formed a loop in stomach, it prevented migration of stent. And also its presence in lumen of stent prevented its obstruction by prolapsing gastric mucosa, thereby preventing seepage of saliva and fluids from side of stent. Both stents and NJT were removed after 6 weeks and leak closed in all patients. Combined cSEMS and NJT placement seems to be safe and effective for treating large lower esophageal perforations. NJT placement seems to decrease risk of migration, prevents seepage of fluids and permits early enteral nutrition, thereby improving the healing rates.

  4. Combined Placement of Covered Self-Expanding Metallic Stents and Nasojejunal Tube for Managing Large Lower Esophageal Perforations

    PubMed Central

    Rana, Surinder S; Gupta, Rajesh; Dahiya, Divya; Behera, Arunanshu; Bhasin, Deepak K

    2014-01-01

    Covered self-expanding metallic stents (cSEMSs) have emerged as effective treatment option for esophageal perforations. However, the large lower esophageal perforations where the cSEMS is placed across gastroesophageal junction have lower healing rates because refluxed gastric contents constantly irritate perforation and also there is increased risk of stent migration. Moreover, gastric mucosa tends to prolapse into lumen of lower end of stent causing its obstruction, leading to seepage of saliva and fluids from upper end of stent even in the patients who are on parenteral nutrition. We present our experience of a novel technique of combined cSEMS and nasojejunal tube (NJT) placement in four patients (two males) with benign large lower esophageal perforations. The NJT was placed through the stent into the jejunum through which patients were given enteral feeding. The stents were placed 5 - 21 days after esophageal perforation with the size of perforation ranging from 4 to 6 cm. As the NJT formed a loop in stomach, it prevented migration of stent. And also its presence in lumen of stent prevented its obstruction by prolapsing gastric mucosa, thereby preventing seepage of saliva and fluids from side of stent. Both stents and NJT were removed after 6 weeks and leak closed in all patients. Combined cSEMS and NJT placement seems to be safe and effective for treating large lower esophageal perforations. NJT placement seems to decrease risk of migration, prevents seepage of fluids and permits early enteral nutrition, thereby improving the healing rates. PMID:27785265

  5. Stress-induced chemical detection using flexible metal-organic frameworks.

    SciTech Connect

    Allendorf, Mark D.; Hesketh, Peter J.; Gall, Kenneth A.; Choudhury, A.; Pikarsky, J.; Andruszkiewicz, Leanne; Houk, Ronald J. T.; Talin, Albert Alec

    2009-09-01

    In this work we demonstrate the concept of stress-induced chemical detection using metal-organic frameworks (MOFs) by integrating a thin film of the MOF HKUST-1 with a microcantilever surface. The results show that the energy of molecular adsorption, which causes slight distortions in the MOF crystal structure, can be efficiently converted to mechanical energy to create a highly responsive, reversible, and selective sensor. This sensor responds to water, methanol, and ethanol vapors, but yields no response to either N{sub 2} or O{sub 2}. The magnitude of the signal, which is measured by a built-in piezoresistor, is correlated with the concentration and can be fitted to a Langmuir isotherm. Furthermore, we show that the hydration state of the MOF layer can be used to impart selectivity to CO{sub 2}. We also report the first use of surface-enhanced Raman spectroscopy to characterize the structure of a MOF film. We conclude that the synthetic versatility of these nanoporous materials holds great promise for creating recognition chemistries to enable selective detection of a wide range of analytes. A force field model is described that successfully predicts changes in MOF properties and the uptake of gases. This model is used to predict adsorption isotherms for a number of representative compounds, including explosives, nerve agents, volatile organic compounds, and polyaromatic hydrocarbons. The results show that, as a result of relatively large heats of adsorption (> 20 kcal mol{sup -1}) in most cases, we expect an onset of adsorption by MOF as low as 10{sup -6} kPa, suggesting the potential to detect compounds such as RDX at levels as low as 10 ppb at atmospheric pressure.

  6. Wall Covering

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The attractive wall covering shown below is one of 132 styles in the Mirror Magic II line offered by The General Tire & Rubber Company, Akron, Ohio. The material is metallized plastic fabric, a spinoff from space programs. Wall coverings are one of many consumer applications of aluminized plastic film technology developed for NASA by a firm later bought by King-Seeley Thermos Company, Winchester, Massachusetts, which now produces the material. The original NASA use was in the Echo 1 passive communications satellite, a "space baloon" made of aluminized mylar; the high reflectivity of the metallized coating enabled relay of communications signals from one Earth station to another by "bouncing" them off the satellite. The reflectivity feature also made the material an extremely efficient insulator and it was subsequently widely used in the Apollo program for such purposes as temperature control of spacecraft components and insulation of tanks for fuels that must be maintained at very low temperatures. I Used as a wall covering, the aluminized material offers extra insulation, reflects light and I resists cracking. In addition to General Tire, King-Seeley also supplies wall covering material to Columbus Coated Fabrics Division of Borden, Incorporated, Columbus, Ohio, among others.

  7. Syntheses of two new hybrid metal-organic polymers using flexible aliphatic dicarboxylates and pyrazine: Crystal structures and magnetic studies

    NASA Astrophysics Data System (ADS)

    Zhang, Chang-Zheng; Mao, Hong-Yan; Wang, Yan-Li; Zhang, Hong-Yun; Tao, Jing-Cao

    2007-02-01

    The reaction of metal ions, flexible aliphatic dicarboxylates and pyrazine in aqueous solution afford two new metal-organic coordination polymers, {[Cu2(μ2-η2-O2C(CH2)2CO2-η2-μ2)2(H2O)2]·2H2O}n (1) and [Eu2(μ2-η2-O2CCH2CO2-η1-μ1)2(μ2-η2-O2CCH2CO2-η2-μ2)(H2O)6]n (2). Polymer 1 contains the paddle-wheel cage dicopper(II) units, forming a one-dimensional (1D) double-stranded chain structure along the a-axis, in which the copper(II) atoms are bridged by the carboxylate groups of four succinates. The intradimer Cu Cu distance is 2.613(2) Å; the interdimer Cu⋯Cu distance is 6.473 Å. To our knowledge, compound 1 represents the first example of a double-stranded chain structure containing dinuclear paddle-wheel type cage. In the three-dimensional (3D) compound 2, each central Eu(III) ion have a distorted monocapped square antiprism coordination geometry. The structure is built up from two types of polymeric chains with [EuO6(H2O)3]n units as tethers, resulting in microporous framework. The magnetic behavior of 1 shows that the occurrence of a strong antiferromagnetic coupling between the copper(II) ions through the short bridges via the carboxyl groups can be obtained; the best fittings to the experimental magnetic susceptibilities gave -2J=314 cm-1.

  8. Covered versus Uncovered Self-Expandable Metal Stents for Managing Malignant Distal Biliary Obstruction: A Meta-Analysis

    PubMed Central

    Sun, Ping; Yu, Qihong; Wang, Kun; Chang, Weilong; Song, Zifang; Zheng, Qichang

    2016-01-01

    Aim To compare the efficacy of using covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (UCSEMSs) to treat objective jaundice caused by an unresectable malignant tumor. Methods We performed a comprehensive electronic search from 1980 to May 2015. All randomized controlled trials comparing the use of CSEMSs and UCSEMSs to treat malignant distal biliary obstruction were included. Results The analysis included 1417 patients enrolled in 14 trials. We did not detect significant differences between the UCSEMS group and the CSEMS group in terms of cumulative stent patency (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.19–4.53; p = 0.93, I2 = 0%), patient survival (HR 0.77, 95% CI 0.05–10.87; p = 0.85, I2 = 0%), overall stent dysfunction (relative ratio (RR) 0.85, M-H, random, 95% CI 0.57–1.25; p = 0.83, I2 = 63%), the overall complication rate (RR 1.26, M-H, fixed, 95% CI 0.94–1.68; p = 0.12, I2 = 0%) or the change in serum bilirubin (weighted mean difference (WMD) -0.13, IV fixed, 95% CI 0.56–0.3; p = 0.55, I2 = 0%). However, we did detect a significant difference in the main causes of stent dysfunction between the two groups. In particular, the CSEMS group exhibited a lower rate of tumor ingrowth (RR 0.25, M-H, random, 95% CI 0.12–0.52; p = 0.002, I2 = 40%) but a higher rate of tumor overgrowth (RR 1.76, M-H, fixed, 95% CI 1.03–3.02; p = 0.04, I2 = 0%). Patients with CSEMSs also exhibited a higher migration rate (RR 9.33, M-H, fixed, 95% CI 2.54–34.24; p = 0.008, I2 = 0%) and a higher rate of sludge formation (RR 2.47, M-H, fixed, 95% CI 1.36–4.50; p = 0.003, I2 = 0%). Conclusions Our meta-analysis indicates that there is no significant difference in primary stent patency and stent dysfunction between CSEMSs and UCSEMSs during the period from primary stent insertion to primary stent dysfunction or patient death. However, when taking further management for occluded stents into consideration, CSEMSs is a

  9. Covered versus Uncovered Self-Expandable Metal Stents for Managing Malignant Distal Biliary Obstruction: A Meta-Analysis.

    PubMed

    Li, Jinjin; Li, Tong; Sun, Ping; Yu, Qihong; Wang, Kun; Chang, Weilong; Song, Zifang; Zheng, Qichang

    2016-01-01

    To compare the efficacy of using covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (UCSEMSs) to treat objective jaundice caused by an unresectable malignant tumor. We performed a comprehensive electronic search from 1980 to May 2015. All randomized controlled trials comparing the use of CSEMSs and UCSEMSs to treat malignant distal biliary obstruction were included. The analysis included 1417 patients enrolled in 14 trials. We did not detect significant differences between the UCSEMS group and the CSEMS group in terms of cumulative stent patency (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.19-4.53; p = 0.93, I2 = 0%), patient survival (HR 0.77, 95% CI 0.05-10.87; p = 0.85, I2 = 0%), overall stent dysfunction (relative ratio (RR) 0.85, M-H, random, 95% CI 0.57-1.25; p = 0.83, I2 = 63%), the overall complication rate (RR 1.26, M-H, fixed, 95% CI 0.94-1.68; p = 0.12, I2 = 0%) or the change in serum bilirubin (weighted mean difference (WMD) -0.13, IV fixed, 95% CI 0.56-0.3; p = 0.55, I2 = 0%). However, we did detect a significant difference in the main causes of stent dysfunction between the two groups. In particular, the CSEMS group exhibited a lower rate of tumor ingrowth (RR 0.25, M-H, random, 95% CI 0.12-0.52; p = 0.002, I2 = 40%) but a higher rate of tumor overgrowth (RR 1.76, M-H, fixed, 95% CI 1.03-3.02; p = 0.04, I2 = 0%). Patients with CSEMSs also exhibited a higher migration rate (RR 9.33, M-H, fixed, 95% CI 2.54-34.24; p = 0.008, I2 = 0%) and a higher rate of sludge formation (RR 2.47, M-H, fixed, 95% CI 1.36-4.50; p = 0.003, I2 = 0%). Our meta-analysis indicates that there is no significant difference in primary stent patency and stent dysfunction between CSEMSs and UCSEMSs during the period from primary stent insertion to primary stent dysfunction or patient death. However, when taking further management for occluded stents into consideration, CSEMSs is a better choice for patients with malignant biliary

  10. Exclusion of metal oxide by an RF sputtered Ti layer in flexible perovskite solar cells: energetic interface between a Ti layer and an organic charge transporting layer.

    PubMed

    Ameen, Sadia; Akhtar, M Shaheer; Seo, Hyung-Kee; Nazeeruddin, Mohammad Khaja; Shin, Hyung-Shik

    2015-04-14

    In this work, the effects of a titanium (Ti) layer on the charge transport and recombination rates of flexible perovskite solar cells were studied. Ti as an efficient barrier layer was deposited directly on PET-ITO flexible substrates through RF magnetic sputtering using a Ti-source and a pressure of ∼5 mTorr. A Ti coated PET-ITO was used for the fabrication of a flexible perovskite solar cell without using any metal oxide layer. The fabricated flexible perovskite solar cell was composed of a PET-ITO/Ti/perovskite (CH3NH3PbI3)/organic hole transport layer of 2,2',7,7'-tetrakis [N,N'-di-p-methoxyphenylamine]-9,9'-spirobifluorene (spiro-OMeTAD)-Li-TFSI/Ag. A high conversion efficiency of ∼8.39% along with a high short circuit current (JSC) of ∼15.24 mA cm(-2), an open circuit voltage (VOC) of ∼0.830 V and a high fill factor (FF) of ∼0.66 was accomplished by the fabricated flexible perovskite solar cell under a light illumination of ∼100 mW cm(-2) (1.5 AM). Intensity-modulated photocurrent (IMPS)/photovoltage spectroscopy (IMVS) studies demonstrated that the fabricated flexible perovskite solar cell considerably reduced the recombination rate.

  11. New V(IV)-based metal-organic framework having framework flexibility and high CO2 adsorption capacity.

    PubMed

    Liu, Ying-Ya; Couck, Sarah; Vandichel, Matthias; Grzywa, Maciej; Leus, Karen; Biswas, Shyam; Volkmer, Dirk; Gascon, Jorge; Kapteijn, Freek; Denayer, Joeri F M; Waroquier, Michel; Van Speybroeck, Veronique; Van Der Voort, Pascal

    2013-01-07

    A vanadium based metal-organic framework (MOF), VO(BPDC) (BPDC(2-) = biphenyl-4,4'-dicarboxylate), adopting an expanded MIL-47 structure type, has been synthesized via solvothermal and microwave methods. Its structural and gas/vapor sorption properties have been studied. This compound displays a distinct breathing effect toward certain adsorptives at workable temperatures. The sorption isotherms of CO(2) and CH(4) indicate a different sorption behavior at specific temperatures. In situ synchrotron X-ray powder diffraction measurements and molecular simulations have been utilized to characterize the structural transition. The experimental measurements clearly suggest the existence of both narrow pore and large pore forms. A free energy profile along the pore angle was computationally determined for the empty host framework. Apart from a regular large pore and a regular narrow pore form, an overstretched narrow pore form has also been found. Additionally, a variety of spectroscopic techniques combined with N(2) adsorption/desorption isotherms measured at 77 K demonstrate that the existence of the mixed oxidation states V(III)/V(IV) in the titled MOF structure compared to pure V(IV) increases the difficulty in triggering the flexibility of the framework.

  12. Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air.

    PubMed

    Kaltenbrunner, Martin; Adam, Getachew; Głowacki, Eric Daniel; Drack, Michael; Schwödiauer, Reinhard; Leonat, Lucia; Apaydin, Dogukan Hazar; Groiss, Heiko; Scharber, Markus Clark; White, Matthew Schuette; Sariciftci, Niyazi Serdar; Bauer, Siegfried

    2015-10-01

    Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highly flexible perovskite solar cells with stabilized 12% efficiency and a power-per-weight as high as 23 W g(-1). To facilitate air-stable operation, we introduce a chromium oxide-chromium interlayer that effectively protects the metal top contacts from reactions with the perovskite. The use of a transparent polymer electrode treated with dimethylsulphoxide as the bottom layer allows the deposition-from solution at low temperature-of pinhole-free perovskite films at high yield on arbitrary substrates, including thin plastic foils. These ultra-lightweight solar cells are successfully used to power aviation models. Potential future applications include unmanned aerial vehicles-from airplanes to quadcopters and weather balloons-for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.

  13. Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air

    NASA Astrophysics Data System (ADS)

    Kaltenbrunner, Martin; Adam, Getachew; Głowacki, Eric Daniel; Drack, Michael; Schwödiauer, Reinhard; Leonat, Lucia; Apaydin, Dogukan Hazar; Groiss, Heiko; Scharber, Markus Clark; White, Matthew Schuette; Sariciftci, Niyazi Serdar; Bauer, Siegfried

    2015-10-01

    Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highly flexible perovskite solar cells with stabilized 12% efficiency and a power-per-weight as high as 23 W g-1. To facilitate air-stable operation, we introduce a chromium oxide-chromium interlayer that effectively protects the metal top contacts from reactions with the perovskite. The use of a transparent polymer electrode treated with dimethylsulphoxide as the bottom layer allows the deposition--from solution at low temperature--of pinhole-free perovskite films at high yield on arbitrary substrates, including thin plastic foils. These ultra-lightweight solar cells are successfully used to power aviation models. Potential future applications include unmanned aerial vehicles--from airplanes to quadcopters and weather balloons--for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.

  14. Insights into the Temperature-Dependent “Breathing” of a Flexible Fluorinated Metal-Organic Framework

    SciTech Connect

    Fernandez, Carlos A.; Thallapally, Praveen K.; McGrail, B. Peter

    2012-10-08

    The framework expansion and contraction upon carbon dioxide uptake was studied in a partially fluorinated metal-organic framework, FMOF-2. The results show framework expansion and contraction (breathing) as a function of pressure and temperature. Even at temperatures as low as -30 ºC, two phase transitions seem to take place with a pressure step (corresponding to the second transition) that is greatly dependent on temperature. This behavior is described by the model proposed by Coudert and co-workers showing that the material seems to undergo two phase transitions that are temperature dependent. The isosteric heats of adsorption at high pressures show a minimum that is concurrent with the region of CO2 loadings where the second pressure step occurs. It was deduced that these lower enthalpy values are a consequence of the energy cost related to the expansion or reopening of the framework. Lastly, the large and reversible breathing behavior may be a product of the combination of the high elasticity of zinc (II) coordination and the apparent high flexibility of the V-shaped organic building block.

  15. Metal oxide nanostructures synthesized on flexible and solid substrates and used for catalysts, UV detectors, and chemical sensors

    NASA Astrophysics Data System (ADS)

    Willander, Magnus; Sadollahkhani, Azar; Echresh, Ahmad; Nur, Omer

    2014-03-01

    In this paper we demonstrate the visibility of the low temperature chemical synthesis for developing device quality material grown on flexible and solid substrates. Both colorimetric sensors and UV photodetectors will be presented. The colorimetric sensors developed on paper were demonstrated for heavy metal detection, in particular for detecting copper ions in aqueous solutions. The demonstrated colorimetric copper ion sensors developed here are based on ZnO@ZnS core-shell nanoparticles (CSNPs). These sensors demonstrated an excellent low detection limit of less than 1 ppm of copper ions. Further the colorimetric sensors operate efficiently in a wide pH range between 4 and 11, and even in turbulent water. The CSNPs were additionally used as efficient photocatalytic degradation element and were found to be more efficient than pure ZnO nanoparticles (NPs). Also p-NiO/n-ZnO thin film/nanorods pn junctions were synthesized by a two-step synthesis process and were found to act as efficient UV photodetectors. Additionally we show the effect of the morphology of different CuO nanostructures on the efficiency of photo catalytic degradation of Congo red organic dye.

  16. Flexible longitudinal magnetization contrast in spectrally overlapped 3D-MSI metal artifact reduction sequences: Technical considerations and clinical impact.

    PubMed

    Koch, Kevin M; Koff, Matthew F; Shah, Parina H; Kanwischer, Adriana; Gui, Dawei; Potter, Hollis G

    2015-11-01

    It has previously been demonstrated that increased overlap of spectral bins in three-dimensional multispectral imaging techniques (3D-MSI) can aid in reducing residual artifacts near metal implants. However, increasing spectral overlap also necessitates consideration of saturation effects for species with long T1 values. Here, an interleaved spectral bin acquisition strategy is presented for overlapping 3D-MSI that allows for flexible choice of repetition times while simultaneously addressing these cross talk concerns. A phantom imaging experiment is used to illustrate the amplified effect of cross talk on 3D-MSI acquisitions. A methodological approach to address cross talk across a variety of prescribed repetition times is then described. Using the presented principles, a clinical subject with a total hip replacement was imaged to generate T1, proton density, and short-tau inversion recovery contrasts. In addition, a fracture instrumentation case was imaged pre- and postcontrast using T1-weighted spectrally overlapped 3D-MSI. Phantom results demonstrate that conventional spectral interleaving approaches can generate unwanted signal characteristics in heavily overlapped 3D-MSI. Clinical images using the presented methods successfully demonstrate T1, proton density, and inversion recovery image contrasts using heavily overlapped 3D-MSI. Through automated management of spectral bin distributions across multiple interleaves, a variety of longitudinal magnetization contrasts can efficiently be acquired without any clinically relevant cross-talk impact using heavily overlapped 3D-MSI. © 2014 Wiley Periodicals, Inc.

  17. Temporary placement of fully covered self-expandable metal stents for the treatment of benign biliary strictures

    PubMed Central

    Chaput, Ulriikka; Vienne, Ariane; Audureau, Etienne; Bauret, Paul; Bichard, Philippe; Coumaros, Dimitri; Napoléon, Bertrand; Ponchon, Thierry; Duchmann, Jean-Christophe; Laugier, René; Lamouliatte, Hervé; Védrenne, Bruno; Gaudric, Marianne; Chaussade, Stanislas; Robin, Françoise; Leblanc, Sarah

    2015-01-01

    Background Endoscopic treatment of benign biliary strictures (BBS) can be challenging. Objective To evaluate the efficacy of fully covered self-expandable metal stents (FCSEMS) in BBS. Methods Ninety-two consecutive patients with BBS (chronic pancreatitis (n = 42), anastomotic after liver transplantation (n = 36), and post biliary surgical procedure (n = 14)) were included. FCSEMS were placed across strictures for 6 months before endoscopic extraction. Early success rate was defined as the absence of biliary stricture or as a minimal residual anomaly on post-stent removal endoscopic retrograde cholangiopancreatography (ERCP). Secondary outcomes were the final success and stricture recurrence rates as well as procedure-related morbidity. Results Stenting was successful in all patients. Stenting associated complications were minor and occurred in 22 (23.9%) patients. Migration occurred in 23 (25%) patients. Stent extraction was successful in all but two patients with proximal stent migration. ERCP after the 6 months stenting showed an early success in 84.9% patients (chronic pancreatitis patients: 94.7%, liver transplant: 87.9%, post-surgical: 61.5%) (p = 0.01). Final success was observed in 57/73 (78.1%) patients with a median follow-up of 12 ± 3.56 months. Recurrence of biliary stricture occurred in 16/73 (21.9%) patients. Conclusions FCSEMS placement is efficient for patients with BBS, in particular for chronic pancreatitis patients. Stent extraction after 6 months indwelling, although generally feasible, may fail in a few cases. PMID:27403307

  18. Temporary placement of fully covered self-expandable metal stents for the treatment of benign biliary strictures.

    PubMed

    Chaput, Ulriikka; Vienne, Ariane; Audureau, Etienne; Bauret, Paul; Bichard, Philippe; Coumaros, Dimitri; Napoléon, Bertrand; Ponchon, Thierry; Duchmann, Jean-Christophe; Laugier, René; Lamouliatte, Hervé; Védrenne, Bruno; Gaudric, Marianne; Chaussade, Stanislas; Robin, Françoise; Leblanc, Sarah; Prat, Frédéric

    2016-06-01

    Endoscopic treatment of benign biliary strictures (BBS) can be challenging. To evaluate the efficacy of fully covered self-expandable metal stents (FCSEMS) in BBS. Ninety-two consecutive patients with BBS (chronic pancreatitis (n = 42), anastomotic after liver transplantation (n = 36), and post biliary surgical procedure (n = 14)) were included. FCSEMS were placed across strictures for 6 months before endoscopic extraction. Early success rate was defined as the absence of biliary stricture or as a minimal residual anomaly on post-stent removal endoscopic retrograde cholangiopancreatography (ERCP). Secondary outcomes were the final success and stricture recurrence rates as well as procedure-related morbidity. Stenting was successful in all patients. Stenting associated complications were minor and occurred in 22 (23.9%) patients. Migration occurred in 23 (25%) patients. Stent extraction was successful in all but two patients with proximal stent migration. ERCP after the 6 months stenting showed an early success in 84.9% patients (chronic pancreatitis patients: 94.7%, liver transplant: 87.9%, post-surgical: 61.5%) (p = 0.01). Final success was observed in 57/73 (78.1%) patients with a median follow-up of 12 ± 3.56 months. Recurrence of biliary stricture occurred in 16/73 (21.9%) patients. FCSEMS placement is efficient for patients with BBS, in particular for chronic pancreatitis patients. Stent extraction after 6 months indwelling, although generally feasible, may fail in a few cases.

  19. Endoscopic suture fixation is associated with reduced migration of esophageal fully covered self-expandable metal stents (FCSEMS).

    PubMed

    Wright, Andrew; Chang, Andrew; Bedi, Aarti Oza; Wamsteker, Erik-Jan; Elta, Grace; Kwon, Richard S; Carrott, Phillip; Elmunzer, B Joseph; Law, Ryan

    2016-12-07

    Esophageal fully covered self-expandable metal stents (FCSEMS) are indicated for the management of benign and malignant conditions of the esophagus including perforations, leaks, and strictures. FCSEMS are resistant to tissue ingrowth and are removable; however, stent migration occurs in 30-55% of cases. Endoscopic suture fixation of FCSEMS has been utilized to decrease the risk of stent migration though data supporting this practice remain limited. The primary aim of this study was to compare clinical outcomes and migration rate of patients who underwent placement of esophageal FCSEMS with and without endoscopic suture fixation. Our single-center, retrospective, cohort study includes patients who underwent esophageal FCSEMS placement with and without endoscopic suture fixation between January 1, 2012, and November 11, 2015. Baseline patient characteristics, procedural details, and clinical outcomes were abstracted. Logistic regression was performed to identify clinical and technical factors associated with outcomes and stent migration. A total of 51 patients underwent 62 FCSEMS placements, including 21 procedures with endoscopic suture fixation and 41 without. Suture fixation was associated with reduced risk of stent migration (OR 0.13, 95% CI 0.03-0.47). Prior stent migration was associated with significantly higher risk of subsequent migration (OR 6.4, 95% CI 1.6-26.0). Stent migration was associated with lower likelihood of clinical success (OR 0.21, 95% CI 0.06-0.69). There was a trend toward higher clinical success among patients undergoing suture fixation (85.7 vs. 60.9%, p = 0.07). Endoscopic suture fixation of FCSEMS was associated with a reduced stent migration rate. Appropriate patient selection for suture fixation of FCSEMS may lead to reduced migration in high-risk patients.

  20. Partially covered self-expandable metal stents versus polyethylene stents for malignant biliary obstruction: A cost-effectiveness analysis

    PubMed Central

    Barkun, Alan N; Adam, Viviane; Martel, Myriam; AlNaamani, Khalid; Moses, Peter L

    2015-01-01

    BACKGROUND/OBJECTIVE: Partially covered self-expandable metal stents (SEMS) and polyethylene stents (PES) are both commonly used in the palliation of malignant biliary obstruction. Although SEMS are significantly more expensive, they are more efficacious than PES. Accordingly, a cost-effectiveness analysis was performed. METHODS: A cost-effectiveness analysis compared the approach of initial placement of PES versus SEMS for the study population. Patients with malignant biliary obstruction underwent an endoscopic retrograde cholangiopancreatography to insert the initial stent. If the insertion failed, a percutaneous transhepatic cholangiogram was performed. If stent occlusion occurred, a PES was inserted at repeat endoscopic retrograde cholangiopancreatography, either in an outpatient setting or after admission to hospital if cholangitis was present. A third-party payer perspective was adopted. Effectiveness was expressed as the likelihood of no occlusion over the one-year adopted time horizon. Probabilities were based on a contemporary randomized clinical trial, and costs were issued from national references. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: A PES-first strategy was both more expensive and less efficacious than an SEMS-first approach. The mean per-patient costs were US$6,701 for initial SEMS and US$20,671 for initial PES, which were associated with effectiveness probabilities of 65.6% and 13.9%, respectively. Sensitivity analyses confirmed the robustness of these results. CONCLUSION: At the time of initial endoscopic drainage for patients with malignant biliary obstruction undergoing palliative stenting, an initial SEMS insertion approach was both more effective and less costly than a PES-first strategy. PMID:26125107

  1. Partially covered self-expandable metal stents versus polyethylene stents for malignant biliary obstruction: a cost-effectiveness analysis.

    PubMed

    Barkun, Alan N; Adam, Viviane; Martel, Myriam; AlNaamani, Khalid; Moses, Peter L

    2015-10-01

    BACKGROUND⁄ Partially covered self-expandable metal stents (SEMS) and polyethylene stents (PES) are both commonly used in the palliation of malignant biliary obstruction. Although SEMS are significantly more expensive, they are more efficacious than PES. Accordingly, a cost-effectiveness analysis was performed. A cost-effectiveness analysis compared the approach of initial placement of PES versus SEMS for the study population. Patients with malignant biliary obstruction underwent an endoscopic retrograde cholangiopancreatography to insert the initial stent. If the insertion failed, a percutaneous transhepatic cholangiogram was performed. If stent occlusion occurred, a PES was inserted at repeat endoscopic retrograde cholangiopancreatography, either in an outpatient setting or after admission to hospital if cholangitis was present. A third-party payer perspective was adopted. Effectiveness was expressed as the likelihood of no occlusion over the one-year adopted time horizon. Probabilities were based on a contemporary randomized clinical trial, and costs were issued from national references. Deterministic and probabilistic sensitivity analyses were performed. A PES-first strategy was both more expensive and less efficacious than an SEMS-first approach. The mean per-patient costs were US$6,701 for initial SEMS and US$20,671 for initial PES, which were associated with effectiveness probabilities of 65.6% and 13.9%, respectively. Sensitivity analyses confirmed the robustness of these results. At the time of initial endoscopic drainage for patients with malignant biliary obstruction undergoing palliative stenting, an initial SEMS insertion approach was both more effective and less costly than a PES-first strategy.

  2. Superconducting Cable Having A Flexible Former

    SciTech Connect

    Hughey, Raburn L.; Sinha, Uday K.; Reece, David S.; Muller, Albert C.

    2005-08-30

    In order to provide a flexible oxide superconducting cable which is reduced in AC loss, tape-shaped superconducting wires covered with a stabilizing metal are wound on a flexible former. The superconducting wires are preferably laid on the former at a bending strain of not more than 0.2%. In laying on the former, a number of tape-shaped superconducting wires are laid on a core member in a side-by-side manner, to form a first layer. A prescribed number of tape-shaped superconducting wires are laid on top of the first layer in a side-by-side manner, to form a second layer. The former may be made of a metal, plastic, reinforced plastic, polymer, or a composite and provides flexibility to the superconducting wires and the cable formed therewith.

  3. Some investigations of the general instability of stiffened metal cylinders III : continuation of tests of wire-braced specimens and preliminary tests of sheet-covered specimens

    NASA Technical Reports Server (NTRS)

    1943-01-01

    This is the third of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report is concerned primarily with the continuation of the tests of wire-braced specimens, and preliminary tests of sheet-covered specimens that had been made in the experimental investigation on the problem of the general instability of stiffened metal cylinders at the C.I.T.

  4. Recurrent Benign Urethral Strictures Treated with Covered Retrievable Self-Expandable Metallic Stents: Long-Term Outcomes over an 18-Year Period.

    PubMed

    Kim, Min Tae; Kim, Kun Yung; Song, Ho-Young; Park, Jung-Hoon; Tsauo, Jiaywei; Wang, Zhe; Kim, Pyeong Hwa

    2017-09-08

    To assess the long-term outcomes of covered retrievable self-expandable metallic stent (REMS) placement for recurrent benign urethral stricture and to compare the outcomes associated with 3 types of covered REMSs. A retrospective study was performed in 54 male patients in whom 114 REMSs were placed between November 1998 and December 2016. These included 26 polyurethane-covered REMSs in 13 patients (group A), 47 internally polytetrafluoroethylene (PTFE)-covered REMSs in 21 patients (group B), and 41 externally PTFE-covered REMSs in 20 patients (group C). The outcomes were analyzed and compared between the groups. Overall clinical success was achieved in 14 of the 54 patients (24%) at 5-year follow-up (group A, 12%; group B, 19%; group C, 40%). The overall complication rate was 60.5%, and the complication rate was significantly higher in group B than in groups A or C (group A vs B, P = .018; group B vs C, P = .002). The median stent indwelling time and maintained patency period were 3.1 months and 108 months, respectively. In multivariate analysis, stent indwelling time was the only significant factor associated with maintained patency. The long-term outcome of covered REMSs has not achieved the desired success rate for the standard treatment of recurrent urethral stricture. However, externally PTFE-covered REMSs showed a better long-term outcome than the other studied types. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

  5. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells.

    PubMed

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C H

    2016-03-21

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.

  6. Self-expandable covered metal tracheal type stent for sealing cervical anastomotic leak after esophagectomy and gastric pull-up: pitfalls and possibilities.

    PubMed

    Lindenmann, Joerg; Matzi, Veronika; Porubsky, Christian; Anegg, Udo; Sankin, Oliver; Gabor, Sabine; Neuboeck, Nicole; Maier, Alfred; Smolle-Juettner, Freyja Maria

    2008-01-01

    From January 2003 to June 2006, 6 patients with leakage of the cervical esophagogastrostomy after esophagectomy and gastric pull-up underwent endoscopic stenting using the self-expandable covered tracheal type device. Anastomotic healing was satisfactory. Stent extraction was performed after an average interval of 91 days. Initial stent migration occurred in 2 patients and post-extraction stenosis developed in 3 patients. Insertion of a self-expandable covered metal tracheal stent represents a safe approach resulting in immediate closure and subsequent healing of cervical anastomotic leakage.

  7. Porous ZnO nanosheet arrays constructed on weaved metal wire for flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Dai, Hui; Zhou, Yong; Chen, Liang; Guo, Binglei; Li, Aidong; Liu, Jianguo; Yu, Tao; Zou, Zhigang

    2013-05-01

    Porous zinc oxide (ZnO) nanosheet (NS) arrays constructed by connected nanocrystallites were built on weaved metal wire (WMW) via hydrothermal treatment followed by calcination, and used as photoanodes for flexible dye-sensitized solar cells (DSSCs). An overall light-to-electricity conversion efficiency (η) of 2.70% was achieved for the DSSC under 100 mW cm-2 illumination, and this η was found to be much higher than that of the DSSC with ZnO nanowire (NW) as the photoanode (0.71%). The far superior performance of the DSSC with ZnO-NS is essentially attributed to: (i) the film consisting of nanosheets with interconnected nanocrystallites can allow relatively direct pathways for the transportation of electrons as the nanosheets have a regular structure with the sheets being oriented to the electrode; (ii) the nanocrystallites assembly and porous character of the nanosheets can provide a large surface area for dye adsorption, which is in favor of enhancing the light absorption and the light propagation; (iii) the nanopores embedded in the nanosheet can act as ``branch lines'' for more efficient electrolyte diffusion into the interstice of the densely packed nanosheets in the array. A further improvement in the efficiency of the DSSC with ZnO-NS was achieved through the atomic layer deposition (ALD) of an ultrathin titanium oxide (TiO2) layer onto the ZnO-NS layer. The larger charge transfer resistance along with the introduction of a TiO2 shell is thought to reduce the surface recombination and thus contribute to the increase in the open circuit voltage (Voc) of the DSCs and higher conversion efficiency (3.09%).Porous zinc oxide (ZnO) nanosheet (NS) arrays constructed by connected nanocrystallites were built on weaved metal wire (WMW) via hydrothermal treatment followed by calcination, and used as photoanodes for flexible dye-sensitized solar cells (DSSCs). An overall light-to-electricity conversion efficiency (η) of 2.70% was achieved for the DSSC under 100 mW cm

  8. High-Performance Flexible Thin-Film Transistors Based on Single-Crystal-like Silicon Epitaxially Grown on Metal Tape by Roll-to-Roll Continuous Deposition Process.

    PubMed

    Gao, Ying; Asadirad, Mojtaba; Yao, Yao; Dutta, Pavel; Galstyan, Eduard; Shervin, Shahab; Lee, Keon-Hwa; Pouladi, Sara; Sun, Sicong; Li, Yongkuan; Rathi, Monika; Ryou, Jae-Hyun; Selvamanickam, Venkat

    2016-11-02

    Single-crystal-like silicon (Si) thin films on bendable and scalable substrates via direct deposition are a promising material platform for high-performance and cost-effective devices of flexible electronics. However, due to the thick and unintentionally highly doped semiconductor layer, the operation of transistors has been hampered. We report the first demonstration of high-performance flexible thin-film transistors (TFTs) using single-crystal-like Si thin films with a field-effect mobility of ∼200 cm(2)/V·s and saturation current, I/lW > 50 μA/μm, which are orders-of-magnitude higher than the device characteristics of conventional flexible TFTs. The Si thin films with a (001) plane grown on a metal tape by a "seed and epitaxy" technique show nearly single-crystalline properties characterized by X-ray diffraction, Raman spectroscopy, reflection high-energy electron diffraction, and transmission electron microscopy. The realization of flexible and high-performance Si TFTs can establish a new pathway for extended applications of flexible electronics such as amplification and digital circuits, more than currently dominant display switches.

  9. Endoscopic Management of Post-Liver Transplantation Biliary Strictures With the Use of Fully Covered Metallic Stents.

    PubMed

    Jiménez-Pérez, M; Melgar Simón, J M; Durán Campos, A; González Grande, R; Rodrigo López, J M; Manteca González, R

    2016-09-01

    The aim of this work was to evaluate the safety and efficacy of a fully covered self-expandable metal stent (FCSEMS) in the treatment of post-liver transplantation biliary strictures. From October 2009 to October 2014, 44 patients with post-liver transplantation biliary stenosis were treated with the use of endoscopic retrograde cholangiography and placement of FCSEMS after informed consent. The FCSEMS was scheduled to remain in situ for 3-6 months. Patients were followed at regular intervals to evaluate for symptoms and liver function tests. Technical success, complications, and patient outcome were analyzed. All of the strictures were anastomotic, 52% having occurred within the 1st year following the transplantation. Placement of the FCSEMS was possible on the 1st attempt in 54% of patients. Stricture resolution at the time of stent removal was seen in 100% of the cases. During an average follow-up of 27.83 ± 18.3 months after stent removal, stenosis recurred in 9 out of 41 patients (21.9%). The average time of recurrence was 11.78 ± 13.3 months. In all of these cases, the recurrence was resolved by means of placement of another FCSEMS. In 4 cases, the recurrence was associated with a migration of the prosthesis, partial in 2 cases and total in 2 cases. Stent migration occurred in a total of 17 of the 41 patients (41.4%), in 13 of the 32 (40.6%) who had no recurrence of stenosis and in 4 of the 9 (44.4%) of those who experienced recurrence. The average numbers of endoscopic retrograde cholangiography studies required per patient were 2.8 in those with no recurrence and 3.3 in those with recurrence. No death was associated with the process. FCSEMS is a safe effective alternative to plastic stents in the treatment of post-transplantation biliary strictures, resulting in a lower risk of complications and better patient acceptance. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Porous ZnO nanosheet arrays constructed on weaved metal wire for flexible dye-sensitized solar cells.

    PubMed

    Dai, Hui; Zhou, Yong; Chen, Liang; Guo, Binglei; Li, Aidong; Liu, Jianguo; Yu, Tao; Zou, Zhigang

    2013-06-07

    Porous zinc oxide (ZnO) nanosheet (NS) arrays constructed by connected nanocrystallites were built on weaved metal wire (WMW) via hydrothermal treatment followed by calcination, and used as photoanodes for flexible dye-sensitized solar cells (DSSCs). An overall light-to-electricity conversion efficiency (η) of 2.70% was achieved for the DSSC under 100 mW cm(-2) illumination, and this η was found to be much higher than that of the DSSC with ZnO nanowire (NW) as the photoanode (0.71%). The far superior performance of the DSSC with ZnO-NS is essentially attributed to: (i) the film consisting of nanosheets with interconnected nanocrystallites can allow relatively direct pathways for the transportation of electrons as the nanosheets have a regular structure with the sheets being oriented to the electrode; (ii) the nanocrystallites assembly and porous character of the nanosheets can provide a large surface area for dye adsorption, which is in favor of enhancing the light absorption and the light propagation; (iii) the nanopores embedded in the nanosheet can act as "branch lines" for more efficient electrolyte diffusion into the interstice of the densely packed nanosheets in the array. A further improvement in the efficiency of the DSSC with ZnO-NS was achieved through the atomic layer deposition (ALD) of an ultrathin titanium oxide (TiO2) layer onto the ZnO-NS layer. The larger charge transfer resistance along with the introduction of a TiO2 shell is thought to reduce the surface recombination and thus contribute to the increase in the open circuit voltage (Voc) of the DSCs and higher conversion efficiency (3.09%).

  11. [MONITORING OF THE CONTENT OF HEAVY METALS AND ELEMENTS IN THE SNOW COVER IN AGRICULTURAL SOILS AT THE TERRITORY OF THE MOSCOW REGION].

    PubMed

    Ermakov, A A; Karpova, E A; Malysheva, A G; Mikhaylova, R I; Ryzhova, I N

    2015-01-01

    The monitoring of snow cover pollution by heavy metals and elements (zinc, copper, lead, cadmium, arsenic, nickel, chromium, strontium, manganese, fluorine, lithium) was performed in 20 districts of the Moscow region in 2009, 2012 and 2013. The assessment of the levels of contamination by heavy metals and elements was given by means of comparison of them with the average values in the snow cover near Moscow in the end of the last century and in some areas of the world, that no exposed to technological environmental impact. 7 districts of Moscow region were characterized by a high content of lead and cadmium in the snow water. It requires the control of water, soil and agricultural products pollution.

  12. A relation between a metallic film covering on diamond formed during growth and nanosized inclusions in HPHT as-grown diamond single crystals

    NASA Astrophysics Data System (ADS)

    Yin, L.-W.; Li, M.-S.; Gong, Z.-G.; Bai, Y.-J.; Li, F.-Z.; Hao, Z.-Y.

    One of the most important characteristics and basic phenomena during diamond growth from liquid metal catalyst solutions saturated with carbon at high temperature-high pressure (HPHT) is that there exists a thin metallic film covering on the growing diamond, through which carbon-atom clusters are delivered to the surface of the growing diamond by diffusion. A study of microstructures of such a metallic film and a relation between the thin metallic film and the inclusions trapped in HPHT as-grown diamond single crystals may be helpful to obtain high-purity diamond single crystals. It was found that both the metallic film and the HPHT as-grown diamond single crystals contain some nanostructured regions. Examination by transmission electron microscopy suggests that the microstructure of the thin metallic film is in accordance with nanosized particles contained in HPHT as-grown diamond single crystals. The nanosized particles with several to several tens of nanometers in dimension distribute homogeneously in the metallic film and in the diamond matrix. Generally, the size of the particles in the thin metallic film is relatively larger than that within the diamond matrix. Selected area electron diffraction patterns suggest that the nanosized particles in the metallic film and nanometer inclusions within the diamond are mainly composed of f.c.c. (FeNi)23C6, hexagonal graphite and cubic γ-(FeNi). The formation of the nanosized inclusions within the diamond single crystals is thought not only to relate to the growth process and rapid quenching from high temperature after diamond synthesis, but also to be associated with large amounts of defects in the diamond, because the free energy in these defect areas is very high. The critical size of carbide, γ-(FeNi)and graphite particles within the diamond matrix should decrease and not increase according to thermodynamic theory during quenching from HPHT to room temperature and ambient pressure.

  13. The way to cover prediction for cytotoxicity for all existing nano-sized metal oxides by using neural network method.

    PubMed

    Fjodorova, Natalja; Novic, Marjana; Gajewicz, Agnieszka; Rasulev, Bakhtiyor

    2017-04-12

    The regulatory agencies should fulfil the data gap in toxicity for new chemicals including nano-sized compounds, like metal oxides nanoparticles (MeOx NPs) according to the registration, evaluation, authorisation and restriction of chemicals (REACH) legislation policy. This study demonstrates the perspective capability of neural network models for prediction of cytotoxicity of MeOx NPs to bacteria Escherichia coli (E. coli) for the widest range of metal oxides extracted from Periodic table. The counter propagation artificial neural network (CP ANN) models for prediction of cytotoxicity of MeOx NPs for data sets of 17, 36 and 72 metal oxides were employed in the study. The cytotoxicity of studied metal oxide NPs was correlated with (i) χ-metal electronegativity (EN) by Pauling scale and composition of metal oxides characterised by (ii) number of metal atoms in oxide, (iii) number of oxygen atoms in oxide and (iv) charge of metal cation in oxide. The paper describes the models in context of five OECD principles of validation models accepted for regulatory use. The recommendations were done for the minimal number of cytotoxicity tests needs for evaluation of the large set of MeOx with different oxidation states. The methodology is expected to be useful for potential hazard assessment of MeOx NPs and prioritisation for further testing and risk assessment.

  14. Flexible Multi-Shock Shield

    NASA Technical Reports Server (NTRS)

    Christiansen, Eric L. (Inventor); Crews, Jeanne L. (Inventor)

    2005-01-01

    Flexible multi-shock shield system and method are disclosed for defending against hypervelocity particles. The flexible multi-shock shield system and method may include a number of flexible bumpers or shield layers spaced apart by one or more resilient support layers, all of which may be encapsulated in a protective cover. Fasteners associated with the protective cover allow the flexible multi-shock shield to be secured to the surface of a structure to be protected.

  15. Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils.

    PubMed

    Kim, Hyeryun; Ohta, Jitsuo; Ueno, Kohei; Kobayashi, Atsushi; Morita, Mari; Tokumoto, Yuki; Fujioka, Hiroshi

    2017-05-18

    GaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient solid-state light sources capable of replacing conventional incandescent and fluorescent lamps. However, their applications are limited to small devices because their fabrication process is expensive as it involves epitaxial growth of GaN by metal-organic chemical vapor deposition (MOCVD) on single crystalline sapphire wafers. If a low-cost epitaxial growth process such as sputtering on a metal foil can be used, it will be possible to fabricate large-area and flexible GaN-based light-emitting displays. Here we report preparation of GaN films on nearly lattice-matched flexible Hf foils using pulsed sputtering deposition (PSD) and demonstrate feasibility of fabricating full-color GaN-based LEDs. It was found that introduction of low-temperature (LT) grown layers suppressed the interfacial reaction between GaN and Hf, allowing the growth of high-quality GaN films on Hf foils. We fabricated blue, green, and red LEDs on Hf foils and confirmed their normal operation. The present results indicate that GaN films on Hf foils have potential applications in fabrication of future large-area flexible GaN-based optoelectronics.

  16. Schottky solar cell using few-layered transition metal dichalcogenides toward large-scale fabrication of semitransparent and flexible power generator.

    PubMed

    Akama, Toshiki; Okita, Wakana; Nagai, Reito; Li, Chao; Kaneko, Toshiro; Kato, Toshiaki

    2017-09-20

    Few-layered transition metal dichalcogenides (TMDs) are known as true two-dimensional materials, with excellent semiconducting properties and strong light-matter interaction. Thus, TMDs are attractive materials for semitransparent and flexible solar cells for use in various applications. Hoewver, despite the recent progress, the development of a scalable method to fabricate semitransparent and flexible solar cells with mono- or few-layered TMDs remains a crucial challenge. Here, we show easy and scalable fabrication of a few-layered TMD solar cell using a Schottky-type configuration to obtain a power conversion efficiency (PCE) of approximately 0.7%, which is the highest value reported with few-layered TMDs. Clear power generation was also observed for a device fabricated on a large SiO2 and flexible substrate, demonstrating that our method has high potential for scalable production. In addition, systematic investigation revealed that the PCE and external quantum efficiency (EQE) strongly depended on the type of photogenerated excitons (A, B, and C) because of different carrier dynamics. Because high solar cell performance along with excellent scalability can be achieved through the proposed process, our fabrication method will contribute to accelerating the industrial use of TMDs as semitransparent and flexible solar cells.

  17. Three-Dimensional Flexible Complementary Metal-Oxide-Semiconductor Logic Circuits Based On Two-Layer Stacks of Single-Walled Carbon Nanotube Networks.

    PubMed

    Zhao, Yudan; Li, Qunqing; Xiao, Xiaoyang; Li, Guanhong; Jin, Yuanhao; Jiang, Kaili; Wang, Jiaping; Fan, Shoushan

    2016-02-23

    We have proposed and fabricated stable and repeatable, flexible, single-walled carbon nanotube (SWCNT) thin film transistor (TFT) complementary metal-oxide-semiconductor (CMOS) integrated circuits based on a three-dimensional (3D) structure. Two layers of SWCNT-TFT devices were stacked, where one layer served as n-type devices and the other one served as p-type devices. On the basis of this method, it is able to save at least half of the area required to construct an inverter and make large-scale and high-density integrated CMOS circuits easier to design and manufacture. The 3D flexible CMOS inverter gain can be as high as 40, and the total noise margin is more than 95%. Moreover, the input and output voltage of the inverter are exactly matched for cascading. 3D flexible CMOS NOR, NAND logic gates, and 15-stage ring oscillators were fabricated on PI substrates with high performance as well. Stable electrical properties of these circuits can be obtained with bending radii as small as 3.16 mm, which shows that such a 3D structure is a reliable architecture and suitable for carbon nanotube electrical applications in complex flexible and wearable electronic devices.

  18. Flexible and metal-free light-emitting electrochemical cells based on graphene and PEDOT-PSS as the electrode materials.

    PubMed

    Matyba, Piotr; Yamaguchi, Hisato; Chhowalla, Manish; Robinson, Nathaniel D; Edman, Ludvig

    2011-01-25

    We report flexible and metal-free light-emitting electrochemical cells (LECs) using exclusively solution-processed organic materials and illustrate interesting design opportunities offered by such conformable devices with transparent electrodes. Flexible LEC devices based on chemically derived graphene (CDG) as the cathode and poly(3,4-ethylenedioxythiophene) mixed with poly(styrenesulfonate) as the anode exhibit a low turn-on voltage for yellow light emission (V = 2.8 V) and a good efficiency 2.4 (4.0) cd/A at a brightness of 100 (50) cd/m(2). We also find that CDG is electrochemically inert over a wide potential range (+1.2 to -2.8 V vs ferrocene/ferrocenium) and exploit this property to demonstrate planar LEC devices with CDG as both the anode and the cathode.

  19. Flexible white organic light-emitting diodes with a multi-metal electrode and a new combination of heteroleptic iridium compound

    NASA Astrophysics Data System (ADS)

    Lee, Ho Won; Yang, Hyung Jin; Yi, Jae Eun; Kim, Young Kwan; Ha, Yunkyoung

    2015-01-01

    Transparent electrodes and heteroleptic iridium complexes have attracted tremendous scientific interest to organic light-emitting diodes (OLEDs) because they have an advantage in that transparent electrodes can replace indium-tin-oxide (ITO) electrode that has structural defects or diffuse indium into the organic layer. Moreover, heteroleptic iridium complexes exhibit high luminescence and quantum yield, as well as superior device performance. Therefore, we propose the use of flexible white OLEDs with semitransparent Ni/Ag/Ni multi-metal layers and a new combination of iridium complex as an orange phosphorescent emitter. We demonstrate that flexible white OLEDs with ITO-free electrodes and new orange phosphorescent emitters have the potential of stable electrical and optical characteristics.

  20. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

    2016-03-01

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

  1. Metal-complex assemblies constructed from the flexible hinge-like ligand H2bhnq: structural versatility and dynamic behavior in the solid state.

    PubMed

    Yamada, Koichi; Yagishita, Sadahiro; Tanaka, Hirokazu; Tohyama, Kazuhiro; Adachi, Keiichi; Kaizaki, Sumio; Kumagai, Hitoshi; Inoue, Katsuya; Kitaura, Ryo; Chang, Ho-Chol; Kitagawa, Susumu; Kawata, Satoshi

    2004-06-07

    Novel metal-complex assemblies constructed from the flexible hinge-like ligand H(2)bhnq (H(2)bhnq=2,2'-bi(3-hydroxy-1,4-naphthoquinone)) have been synthesized. The X-ray crystal structures of these compounds reveal that four types of architectures are accessible by variation of the metal ions. In copper(II) compounds 1-3, the chelating bhnq(2-) ions bridge copper(II) centers to form one-dimensional zigzag chains. The chains of 1-3 are arranged by hydrogen-bonding interactions and stacking interactions to produce porous structures. Cobalt(II) and zinc(II) compounds 4 and 5 form one-dimensional helical chains. In 4 and 5, the crystal packing induces spontaneous resolution of the helical chains with chiral cavities formed perpendicular to the helices. Nickel(II) compounds 6 and 7 form cyclic tetramers. The fourth architecture, a dimer (compound 8), is obtained by the reaction of zinc(II) and bhnq(2-) in MeOH. In these compounds, changes of the dihedral angles and the metal-coordination mode of the bhnq(2-) ion induce the structural versatility. The assemblies of the zigzag chains of the copper(II) compounds exhibit reversible vapochromic behavior. UV/Vis, powder X-ray diffraction, EPR, and adsorption isotherm measurements indicate that this vapochromic behavior is based on the hinge-like flexibility of the bhnq(2-) ion.

  2. Improvement of optical and electric characteristics of MoO3/Ag film/MoO3 flexible transparent electrode with metallic grid

    NASA Astrophysics Data System (ADS)

    Wang, Chen-Tao; Ting, Chu-Chi; Kao, Po-Ching; Li, Shan-Rong; Chu, Sheng-Yuan

    2016-11-01

    In this paper, the authors report rationally designed, innovative tri-layer flexible transparent conductive electrodes (TCEs) fabricated via thermal deposition. The proposed structure improves transparency compared with that of the traditional tri-layer electrode (dielectric/metal film/dielectric) by using metallic grid patterns (dielectric/metal grids/dielectric). The obtained MoO3/Ag grids/MoO3 TCEs show low sheet resistance and good mechanical properties. The sheet resistance of the proposed electrodes is 5.88 Ω/square and the transmittance reaches 76.5%, which are better than those of conventional MoO3/Ag film/MoO3 electrodes (6.12 Ω/square, <70%). The mechanical properties are significantly improved compared with those of MoO3/Ag film/MoO3 in the bending test under both tensile and compressive stress. The surface features of the MoO3/Ag grids/MoO3 TCEs were measured using the contact angle method to calculate the surface energy and polarity. The polarity is 0.5-0.26, which is better than those of indium tin oxide (0.35) and MoO3/Ag film/MoO3 (0.5-0.0058) electrodes for 0-800 bending cycles. The proposed flexible transparent electrodes show good optical, electrical, and mechanical characteristics and have potential for application in optoelectronics.

  3. Crosslinking metal nanoparticles into the polymer backbone of hydrogels enables preparation of soft, magnetic field-driven actuators with muscle-like flexibility.

    PubMed

    Fuhrer, Roland; Athanassiou, Evagelos Kimon; Luechinger, Norman Albert; Stark, Wendelin Jan

    2009-03-01

    The combination of force and flexibility is at the core of biomechanics and enables virtually all body movements in living organisms. In sharp contrast, presently used machines are based on rigid, linear (cylinders) or circular (rotator in an electrical engine) geometries. As a potential bioinspired alternative, magnetic elastomers can be realized through dispersion of micro- or nanoparticles in polymer matrices and have attracted significant interest as soft actuators in artificial organs, implants, and devices for controlled drug delivery. At present, magnetic particle loss and limited actuator strength have restricted the use of such materials to niche applications. We describe the direct incorporation of metal nanoparticles into the backbone of a hydrogel and application as an ultra-flexible, yet strong magnetic actuator. Covalent bonding of the particles prevents metal loss or leaching. Since metals have a far higher saturation magnetization and higher density than oxides, the resulting increased force/volume ratio afforded significantly stronger magnetic actuators with high mechanical stability, elasticity, and shape memory effect.

  4. Hybrid Flexible and Rigid Ceramic Insulation

    NASA Technical Reports Server (NTRS)

    Rasky, Daniel J. (Inventor); Kourtides, Demetrius A. (Inventor)

    1996-01-01

    A method is provided for closing out the edges of a flexible ceramic insulation member including inner and outer mold line covering layers. A rigid, segmented, ceramic frame is placed round the edges of the insulation member and exposed edges of the inner and outer mold line covering layers are affixed to the ceramic frame. In one embodiment wherein the covering layers comprise fabrics, the outer fabric is bonded to the top surface and to grooved portion of the side surface of the frame. In another embodiment wherein the outer cover layer comprises a metallic foil, clips on the edges of the frame are used to engage foil extensions. The ceramic frame is coated with a high emittance densifier coating.

  5. Serum-cobalt levels with metal-on-metal bearings in the cement-free total hip arthroplasty results covering two years; prospective study.

    PubMed

    Weissinger, M; Grübl, A; Pöll, G

    2011-01-01

    Total hip arthroplasty increases the use of alternate bearings to prevent polyethylene wear as the number of younger and more active patients has drastically risen. We carried out a prospective randomized study, to assess and compare clinical results and radiological changes, serum-cobalt- and serum-aluminium-levels when metal-on-metal and ceramic-on-ceramic bearings are applicated. After giving informed consent 80 consecutive patients were included in this prospective randomized study. They were randomly assigned to receive either a metal-on-metal or a ceramic-on-ceramic bearing in their total hip replacement. Eligible were patients with a primary coxarthrosis or an avascular necrosis of the head of femur. Of the 80 patients 54 were females and 26 males. 42 patients were randomized to a metal-on-metal bearing and 38 patients were randomized to a ceramic-on-ceramic bearing. The average patient-age was 65,8 years and the mean body mass index was 27,7 at the time of operation. Surgery was performed through a transgluteal approach in supine position under general or spinal anaesthesia. A forged conical threaded acetabular component made of titanium-aluminium-niobium alloy was used in all patients. The metal inlays and the 28 mm metal heads were made of Co-28Cr-6Mo alloy with a carbon content of 0,2%. The ceramic inlays and the 28 mm ceramic heads are Al2O3 implants. We used as femoral component a conical rectangular stem of a titanium-aluminium-niobium alloy. Cup and stem werde implanted cementfree. Clinical data werde obtained at a follow up at a minimum of two years after implantation. Patients were assessed with the Harris Hip Score and the University of California at Los Angeles activity scale. 72 of the 80 patients could be explored clinically and radiologically. The 2 year follow up check showed clinically and radiologically no difference between the two groups. The median Harris HipScore was above 90 points and the UCLA score was about 7 points. The medium

  6. Modeling and experimental studies of oxide covered metal surfaces: TiO{sub 2}/Ti a model system. Progress report

    SciTech Connect

    Smyrl, W.H.

    1991-12-31

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  7. Modeling and experimental studies of oxide covered metal surfaces: TiO sub 2 /Ti a model system

    SciTech Connect

    Smyrl, W.H.

    1991-01-01

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  8. Guidance and control of MIR TDL radiation via flexible hollow metallic rectangular pipes and fibers for possible LHS and other optical system compaction and integration

    NASA Technical Reports Server (NTRS)

    Yu, C.

    1983-01-01

    Flexible hollow metallic rectangular pipes and infrared fibers are proposed as alternate media for collection, guidance and manipulation of mid-infrared tunable diode laser (TDL) radiation. Certain features of such media are found to be useful for control of TDL far field patterns, polarization and possibly intensity fluctuations. Such improvement in dimension compatibility may eventually lead to laser heterodyne spectroscopy (LHS) and optical communication system compaction and integration. Infrared optical fiber and the compound parabolic coupling of light into a hollow pipe waveguide are discussed as well as the design of the waveguide.

  9. Laser-assisted photoemission from adsorbate-covered metal surfaces: Time-resolved core-hole relaxation dynamics from sideband profiles

    NASA Astrophysics Data System (ADS)

    Zhang, C.-H.; Thumm, U.

    2009-09-01

    Illumination of an adsorbate-covered metal surface with an xuv and a delayed ir laser pulse can result in sidebands in the photoelectron (PE) spectra. We present a theoretical model for the delay-dependent PE spectra and show how the relaxation dynamics of xuv-induced core-level holes in adsorbate atoms can be deduced from the temporal shift between sideband peaks in the spectra of secondary adsorbate (Auger) electrons and conduction-band PEs from the substrate. Furthermore, in comparison with gaseous targets, we find a characteristic sideband-intensity enhancement in the laser-assisted photoemission from the substrate core-level bands. This sideband enhancement effect can be tested in experiments with tunable xuv wavelength. Our calculated PE spectra support time-resolved experiments for Xe-covered Pt(111) surfaces, promoting the direct analysis in the time domain of surface dynamical processes.

  10. Reusable pipe flange covers

    DOEpatents

    Holden, James Elliott; Perez, Julieta

    2001-01-01

    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  11. Laser-Direct Writing of Silver Metal Electrodes on Transparent Flexible Substrates with High-Bonding Strength.

    PubMed

    Zhou, Weiping; Bai, Shi; Ma, Ying; Ma, Delong; Hou, Tingxiu; Shi, Xiaomin; Hu, Anming

    2016-09-21

    We demonstrate a novel approach to rapidly fabricate conductive silver electrodes on transparent flexible substrates with high-bonding strength by laser-direct writing. A new type of silver ink composed of silver nitrate, sodium citrate, and polyvinylpyrrolidone (PVP) was prepared in this work. The role of PVP was elucidated for improving the quality of silver electrodes. Silver nanoparticles and sintered microstructures were simultaneously synthesized and patterned on a substrate using a focused 405 nm continuous wave laser. The writing was completed through the transparent flexible substrate with a programmed 2D scanning sample stage. Silver electrodes fabricated by this approach exhibit a remarkable bonding strength, which can withstand an adhesive tape test at least 50 times. After a 1500 time bending test, the resistance only increased 5.2%. With laser-induced in-situ synthesis, sintering, and simultaneous patterning of silver nanoparticles, this technology is promising for the facile fabrication of conducting electronic devices on flexible substrates.

  12. Endoscopic radiofrequency ablation combined with fully covered self-expandable metal stent for inoperable periampullary carcinoma in a liver transplant patient

    PubMed Central

    Tian, Qing; Wang, Guijie; Zhang, Yamin; Jin, Yan; Cui, Zilin; Sun, Xiaoye; Shen, Zhongyang

    2017-01-01

    Abstract Rationale: Postliver transplant periampullary carcinoma is an extremely uncommon disease. Patient concerns: Cutaneous jaundice in a patient who had received a liver transplant 4 years earlier. Diagnosis: Periampullary carcinoma. Interventions: Radiofrequency ablation plus fully covered self-expanding metal stents (FCSEMS). Outcomes: The treatment of malignant neoplasm of the ampulla of Vater is the patient by radiofrequency ablation plus FCSEMS placement was successful. No complications occurred. Lessons: This is the first reported case of a liver transplant patient with inoperable periampullary carcinoma successfully treated by radiofrequency ablation plus FCSEMS placement. Our experience will be useful to other surgeons in managing similar patients in the future. PMID:28151854

  13. Metal and Phosphorous behavior in the water and sediment underneath ice cover: a comparative study between hyper- and eutrophic lake systems

    NASA Astrophysics Data System (ADS)

    Joung, D.; Xu, Y.; Isles, P. D.; Gearhart, T.; Stockwell, J.; O'Malley, B.; Schroth, A. W.; Ramcharitar, B.; Leduc, M.

    2015-12-01

    The behavior of metals and associated nutrients in lakes under ice cover is poorly understood, although wintertime metal nutrient dynamics near the sediment water interface (SWI) could impact water quality and algal ecosystems. To examine the behavior of these biogeochemical constituents under ice, we collected water column and sediment time series biogeochemical data from hyper-eutrophic Shelburne Pond (SP) and eutrophic Missisquoi Bay (MB), Vermont USA, from January to April 2015. Based on temporal changes in the concentration of Al, Ca, Fe, Mn and P in sediment, coupled with density and oxygen gradients in water, we demonstrate that water column variability in metal and P concentration and spatial distribution is impacted by redox cycling near the SWI, as well as episodic input from each system's watershed. These processes are manifest differently in each system due to differences in lake-watershed configuration and sediment composition. Our data suggest that under ice nutrient and metal partitioning, flux and concentration distribution is highly dynamic in both time and space, and a complex interaction between SWI redox chemistry, hydrodynamics, and winter weather. These drivers control the biogeochemical evolution of the under ice system during the winter, with the potential to impact water quality and spring/summer ecosystem productivity.

  14. Dispersion of functional tetraphenylporphyrin-ligated metal into ultra-thin flexible acrylate films. 1. Preparation of thin films.

    PubMed

    Choe, Youngson; Kim, Taesu; Kim, Wonho

    2004-11-15

    As functional metal complexes, copper phthalocyanine (CuPc) and Cobalt (II) meso-tetraphenylporphyrin (CoTPP) were chosen to prepare metal complex/polymer hybrid thin films which were prepared by metal complex sublimation and reactive monomer evaporation onto the glass substrate in the bell jar reactor in vacuum conditions. The polarized transmission micrograph images show that the film deposited at 80 degrees C contains uniformly dispersed tiny grains and the film deposited at 30 degrees C is amorphous and homogeneous. As the deposition rate increases, the crystalline clusters were found and were dispersed uniformly. Those crystalline clusters are not to be developed by recrystallization process. Deposited metal complex/acrylate hybrid thin films were in situ photopolymerized. The kinetics of photopolymerization was investigated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The thickness of the films was about 200 nm. The reactive monomer acts as a solvent to avoid the recrystallization of metal complexes and to have two-compositional continuous phase. The percent of metal complex can be adjusted up to 60% by controlling the metal complex sublimation rate. A good achievement in the uniformity and continuity of the film matrix has been made and the recrystallization of metal complex in the hybrid films has not been observed.

  15. WATER COOLED RETORT COVER

    DOEpatents

    Ash, W.J.; Pozzi, J.F.

    1962-05-01

    A retort cover is designed for use in the production of magnesium metal by the condensation of vaporized metal on a collecting surface. The cover includes a condensing surface, insulating means adjacent to the condensing surface, ind a water-cooled means for the insulating means. The irrangement of insulation and the cooling means permits the magnesium to be condensed at a high temperature and in massive nonpyrophoric form. (AEC)

  16. Fully covered, self-expandable metal stents for first-step endoscopic treatment of biliary leaks secondary to hepato-biliary surgery: a retrospective study.

    PubMed

    Mangiavillano, Benedetto; Luigiano, Carmelo; Tarantino, Ilaria; Barresi, Luca; Dinelli, Marco; Frego, Roberto; Bassi, Marco; Fabbri, Carlo; Cennamo, Vincenzo; Viaggi, Paolo; Traina, Mario; Santoro, Tara; Masci, Enzo

    2013-05-01

    Fully covered self-expanding metal stents are now being used to treat benign biliary diseases. To assess the outcomes of these stents as first-step therapy in patients with biliary leaks secondary to hepato-biliary surgery. Thirty patients (56.7% males; mean age: 60.2 ± 13 years) were retrospectively evaluated. The data collected included technical and clinical success, adverse events and follow-up findings (1, 3 and 6 months). Technical and clinical success rates were 100%. One early mild post-procedure pancreatitis occurred and resolved spontaneously. Three late stent distal migrations occurred, however cholangiography showed correct leak sealing in all patients. Stents were removed after a mean of 55.9 days. During follow-up no other complications occurred. In our experience fully covered self-expanding metal stent placement was safe and efficacious as first-step therapy for post-operative biliary leaks. However, prospective comparative studies with plastic stents are required to validate these findings. Copyright © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  17. Flexible micro-supercapacitor based on in-situ assembled graphene on metal template at room temperature

    SciTech Connect

    Wu, ZK; Lin, ZY; Li, LY; Song, B; Moon, KS; Bai, SL; Wong, CP

    2014-11-01

    Graphene based micro-supercapacitors (MSCs) have been extensively studied in recent years; however, few of them report room temperature fabricating methods for flexible MSC. Here we developed a convenient procedure based on simultaneous self-assembly and reduction of graphene oxide (GO) on Cu/Au interdigit at room temperature. The as-produced MSC shows a specific areal capacitance of 0.95 mF cm(-2) and maintains 98.3% after 11,000 cycles of charge and discharge. Extremely small relaxation time constants of 1.9 ms in aqueous electrolyte and 4.8 ms in gelled electrolyte are achieved. Also the device shows great flexibility and retains 93.5% of the capacitance after 5000 times of bending and twisting tests. (C) 2014 Elsevier Ltd. All rights reserved.

  18. Enhancement of Characteristics of Transparent Conductive Electrode on Flexible Substrate by Combination of Solution-Based Oxide and Metallic Layers.

    PubMed

    Hong, Sung-Jei; Kim, Yong-Hoon; Cha, Seung-Jae; Kim, Yong-Sung

    2015-10-01

    This study investigates solution-processed transparent conductors with hybrid structure consisting of silver nanowires (AgNWs) and indium-tin-oxide nanoparticles (ITO-NPs) layers fabricated on polymeric flexible polyethylene terephthalate (PET) substrate. The transparent conductors had stacked structures of AgNWs/ITO-NPs on 125-μm-thick PET and ITO-NPs/AgNWs/ITO-NPs on 125-μm-thick PET, 188-μm-thick PET, or 700-μm-thick glass substrate, respectively. Successful integrations were possible on the substrates without any deformation or distortion. Sheet resistance of the triple-layered transparent conductor samples exhibits low values ranging from 22.41 Ω/square to 22.99 Ω/squarer. Also, their optical transmittance exhibits high values ranging from 83.78 to 87.29% at 550 nm. The triple-layered transparent conductor showed a good thermal stability in terms of sheet resistance and optical transmittance against the high-temperature environment up to 250 °C. All the double and triple-layered transparent conductors fabricated on PET and glass substrates are so stable against the accelerated thermal aging from 110 °C to 130 °C, that ΔR/R0 and ΔT(550)/T0(550) values exhibit less than 0.068 and 0.049, respectively. Furthermore, the layers are so flexible that ΔR/R0 of the layers on PET substrates is lower than 0.1 even at 4.0-mm bending. Especially, triple-layered transparent conductor on 125-μm-thick PET substrates exhibits ΔR/R0 value of 0.042 even at 4.0 mm bending. Thus, it can be concluded that the hybrid structures have the advantage of both thermal stability and flexibility for electrical and optical properties of transparent conductive electrode; which makes them highly applicable in flexible electronics.

  19. Metal-organic frameworks as potential shock absorbers: the case of the highly flexible MIL-53(Al).

    PubMed

    Yot, Pascal G; Boudene, Zoubeyr; Macia, Jasmine; Granier, Dominique; Vanduyfhuys, Louis; Verstraelen, Toon; Van Speybroeck, Veronique; Devic, Thomas; Serre, Christian; Férey, Gérard; Stock, Norbert; Maurin, Guillaume

    2014-08-28

    The mechanical energy absorption ability of the highly flexible MIL-53(Al) MOF material was explored using a combination of experiments and molecular simulations. A pressure-induced transition between the large pore and the closed pore forms of this solid was revealed to be irreversible and associated with a relatively large energy absorption capacity. Both features make MIL-53(Al) the first potential MOF candidate for further use as a shock absorber.

  20. The Coupled Photothermal Reaction and Transport in a Laser Additive Metal Nanolayer Simultaneous Synthesis and Pattering for Flexible Electronics.

    PubMed

    Tsai, Song-Ling; Liu, Yi-Kai; Pan, Heng; Liu, Chien-Hung; Lee, Ming-Tsang

    2016-01-08

    The Laser Direct Synthesis and Patterning (LDSP) technology has advantages in terms of processing time and cost compared to nanomaterials-based laser additive microfabrication processes. In LDSP, a scanning laser on the substrate surface induces chemical reactions in the reactive liquid solution and selectively deposits target material in a preselected pattern on the substrate. In this study, we experimentally investigated the effect of the processing parameters and type and concentration of the additive solvent on the properties and growth rate of the resulting metal film fabricated by this LDSP technology. It was shown that reactive metal ion solutions with substantial viscosity yield metal films with superior physical properties. A numerical analysis was also carried out the first time to investigate the coupled opto-thermo-fluidic transport phenomena and the effects on the metal film growth rate. To complete the simulation, the optical properties of the LDSP deposited metal film with a variety of thicknesses were measured. The characteristics of the temperature field and the thermally induced flow associated with the moving heat source are discussed. It was shown that the processing temperature range of the LDSP is from 330 to 390 K. A semi-empirical model for estimating the metal film growth rate using this process was developed based on these results. From the experimental and numerical results, it is seen that, owing to the increased reflectivity of the silver film as its thickness increases, the growth rate decreases gradually from about 40 nm at initial to 10 nm per laser scan after ten scans. This self-controlling effect of LDSP process controls the thickness and improves the uniformity of the fabricated metal film. The growth rate and resulting thickness of the metal film can also be regulated by adjustment of the processing parameters, and thus can be utilized for controllable additive nano/microfabrication.

  1. The Coupled Photothermal Reaction and Transport in a Laser Additive Metal Nanolayer Simultaneous Synthesis and Pattering for Flexible Electronics

    PubMed Central

    Tsai, Song-Ling; Liu, Yi-Kai; Pan, Heng; Liu, Chien-Hung; Lee, Ming-Tsang

    2016-01-01

    The Laser Direct Synthesis and Patterning (LDSP) technology has advantages in terms of processing time and cost compared to nanomaterials-based laser additive microfabrication processes. In LDSP, a scanning laser on the substrate surface induces chemical reactions in the reactive liquid solution and selectively deposits target material in a preselected pattern on the substrate. In this study, we experimentally investigated the effect of the processing parameters and type and concentration of the additive solvent on the properties and growth rate of the resulting metal film fabricated by this LDSP technology. It was shown that reactive metal ion solutions with substantial viscosity yield metal films with superior physical properties. A numerical analysis was also carried out the first time to investigate the coupled opto-thermo-fluidic transport phenomena and the effects on the metal film growth rate. To complete the simulation, the optical properties of the LDSP deposited metal film with a variety of thicknesses were measured. The characteristics of the temperature field and the thermally induced flow associated with the moving heat source are discussed. It was shown that the processing temperature range of the LDSP is from 330 to 390 K. A semi-empirical model for estimating the metal film growth rate using this process was developed based on these results. From the experimental and numerical results, it is seen that, owing to the increased reflectivity of the silver film as its thickness increases, the growth rate decreases gradually from about 40 nm at initial to 10 nm per laser scan after ten scans. This self-controlling effect of LDSP process controls the thickness and improves the uniformity of the fabricated metal film. The growth rate and resulting thickness of the metal film can also be regulated by adjustment of the processing parameters, and thus can be utilized for controllable additive nano/microfabrication.

  2. Electromagnetic modeling of the energy distribution of a metallic cylindrical parabolic reflector covered with a magnetized plasma layer

    SciTech Connect

    Niknam, A. R. Khajehmirzaei, M. R.; Davoudi-Rahaghi, B.; Rahmani, Z.; Jazi, B.; Abdoli-Arani, A.

    2014-07-15

    The energy distribution along the focal axis of a long metallic cylindrical parabolic reflector with a plasma layer on its surface in the presence of an external magnetic field is investigated. The effects of some physical parameters, such as the plasma frequency, the wave frequency and the thickness of plasma layer on the energy distribution and the reflected and transmitted electromagnetic fields, are simulated. These investigations for both S- and P-polarizations have been done separately. It is found that the maximum value of the reflected intensity increases by increasing the incident wave frequency and by decreasing the plasma layer thickness and the plasma frequency for both polarizations. Furthermore, the results show that the increase of the magnetic field strength can cause an increase in the reflected intensity for S-polarization and a slight decrease for P-polarization.

  3. Energy Transfer in a Cylindrical Nanostructure Consisting of a Metal Wire and a Coaxial Covering with Luminophore Molecules

    NASA Astrophysics Data System (ADS)

    Kucherenko, M. G.; Chmereva, T. M.

    2017-07-01

    Light absorption and nonradiative exchange of electronic excitation energy between a metal nanowire with a circular cross section and luminophore molecules surrounding it were studied theoretically. The energy-transfer rate from a single excited molecule to the nanowire and the decay kinetics of the luminophore excited state were calculated for molecules that did not interact with each other. The energy-transfer rate from a coaxial monolayer formed by molecules joined into J-aggregate complexes to the nanowire was also calculated. It was shown that a hybrid exciton-plasmon state could be generated. The geometric characteristics of the examined systems were found to influence considerably the electronic excitation energy transformation rate.

  4. Effects of soil amendments at a heavy loading rate associated with cover crops as green manures on the leaching of nutrients and heavy metals from a calcareous soil.

    PubMed

    Wang, Qing-Ren; Li, Yun-Cong; Klassen, Waldemar

    2003-11-01

    The potential risk of groundwater contamination by the excessive leaching of N, P and heavy metals from soils amended at heavy loading rates of biosolids, coal ash, N-viro soil (1:1 mixture of coal ash and biosolids), yard waste compost and co-compost (3:7 mixture of biosolids to yard wastes), and by soil incorporation of green manures of sunn hemp (Crotalaria juncea) and sorghum sudangrass (Sorghum bicolor x S. bicolor var. sudanense) was studied by collecting and analyzing leachates from pots of Krome very gravelly loam soil subjected to these treatments. The control consisted of Krome soil without any amendment. The loading rate was 205 g pot(-1) for each amendment (equivalent to 50 t ha(-1) of the dry weight), and the amounts of the cover crops incorporated into the soil in the pot were those that had been grown in it. A subtropical vegetable crop, okra (Abelmoschus esculentus L.), was grown after the soil amendments or cover crops had been incorporated into the soil. The results showed that the concentration of NO3-N in leachate from biosolids was significantly higher than in leachate from other treatments. The levels of heavy metals found in the leachates from all amended soils were so low, as to suggest these amendments may be used without risk of leaching dangerous amounts of these toxic elements. Nevertheless the level of heavy metals in leachate from coal ash amended soil was substantially greater than in leachates from the other treatments. The leguminous cover crop, sunn hemp, returned into the soil, increased the leachate NO3-N and inorganic P concentration significantly compared with the non-legume, sorghum sudangrass. The results suggest that at heavy loading rates of soil amendments, leaching of NO3- could be a significant concern by application of biosolids. Leaching of inorganic P can be increased significantly by both co-compost and biosolids, but decreased by coal ash and N-viro soil by virtue of improved adsorption. The leguminous cover crop

  5. FLEXIBLE COUPLING

    DOEpatents

    Babelay, E.F.

    1962-02-13

    A flexible shaft coupling for operation at speeds in excess of 14,000 rpm is designed which requires no lubrication. A driving sleeve member and a driven sleeve member are placed in concentric spaced relationship. A torque force is transmitted to the driven member from the driving member through a plurality of nylon balls symmetrically disposed between the spaced sleeves. The balls extend into races and recesses within the respective sleeve members. The sleeve members have a suitable clearance therebetween and the balls have a suitable radial clearance during operation of the coupling to provide a relatively loose coupling. These clearances accommodate for both parallel and/or angular misalignments and avoid metal-tometal contact between the sleeve members during operation. Thus, no lubrication is needed, and a minimum of vibrations is transmitted between the sleeve members. (AEC)

  6. The effect and safety of dressing composed by nylon threads covered with metallic silver in wound treatment.

    PubMed

    Brogliato, Ariane R; Borges, Paula A; Barros, Janaina F; Lanzetti, Manuela; Valença, Samuel; Oliveira, Nesser C; Izário-Filho, Hélcio J; Benjamim, Claudia F

    2014-04-01

    Silver is used worldwide in dressings for wound management. Silver has demonstrated great efficacy against a broad range of microorganisms, but there is very little data about the systemic absorption and toxicity of silver in vivo. In this study, the antimicrobial effect of the silver-coated dressing (SilverCoat(®)) was evaluated in vitro against the most common microorganisms found in wounds, including Pseudomonas aeruginosa, Candida albicans, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus and Klebsiella pneumoniae. We also performed an excisional skin lesion assay in mice to evaluate wound healing after 14 days of treatment with a silver-coated dressing, and we measured the amount of silver in the blood, the kidneys and the liver after treatment. Our data demonstrated that the nylon threads coated with metallic silver have a satisfactory antimicrobial effect in vitro, and the prolonged use of these threads did not lead to systemic silver absorption, did not induce toxicity in the kidneys and the liver and were not detrimental to the normal wound-healing process.

  7. Potential of a Hydrometallurgical Recycling Process for Catalysts to Cover the Demand for Critical Metals, Like PGMs and Cerium

    NASA Astrophysics Data System (ADS)

    Steinlechner, Stefan; Antrekowitsch, Jürgen

    2015-02-01

    The metals from the platinum group are used in many different industries, for example dental, jewelry, and chemicals. Nevertheless, the most important use is based on their catalytic properties. Approximately 50% of platinum and palladium are used as automotive and industrial catalysts. In case of rhodium, an even higher percentage (around 80-90%) is used as an alloying element in the active layer of different catalysts. The high required amount of 300-900 kg of treated ore to obtain approximately 1 g of PGM is responsible for the high prices. On average, the contents in the ore of Pt and Pd are 5-10 times higher than Rh and Ru and around 50 times higher than Ir and Os. Additionally, the regional limitation of ore bodies leads to a strong dependence on mainly South Africa and Russia as PGM suppliers. Based on the strong discrepancy in supply and demand of PGM's around the world, recycling of catalysts is mandatory and meaningful from the ecological and economical point of view. Based on the high prices of PGM, the industry is forced to improve the efficiency of catalysts, which is done by improving the wash coat technology. By using rare-earth elements, like cerium oxide, the surface can be increased and the ability to supply oxygen is secured. As a side effect, cerium as an additional critical element is introduced into the recycling circuit of catalytic converters, forming a further valuable component and forming a major challenge for common pyrometallurgical converter recycling. Therefore, this article introduces a hydrometallurgical process, developed together with Railly&Hill Inc., for PGM as well as cerium recovery from catalytic converters.

  8. Placement of a new fully covered self-expanding metal stent for postoperative biliary strictures and leaks not responding to plastic stenting.

    PubMed

    Luigiano, Carmelo; Bassi, Marco; Ferrara, Francesco; Fabbri, Carlo; Ghersi, Stefania; Morace, Carmela; Consolo, Pierluigi; Maimone, Antonella; Galluccio, Gabriella; D'Imperio, Nicola; Cennamo, Vincenzo

    2013-04-01

    Fully covered self-expanding metal stents (FCSEMSs) are now being used to treat postoperative biliary strictures (BSs) and biliary leaks (BLs). The aim of this study was to assess the safety and effectiveness of a new FCSEMS (Wallflex) in patients with postoperative BSs and BLs after failure of traditional endoscopic treatment. Between January 2010 and December 2011, 16 patients (10 patients with postcholecystectomy BSs, 4 with postcholecystectomy BLs, and 2 with postorthotopic liver transplantation BSs) were enrolled. The technical and clinical success rate was 100%. All FCSEMSs were removed after a mean of 141 days. Complications occurred in 7 cases: 2 postprocedure pain, 2 mild pancreatitis, 1 early distal, and 2 late proximal FCSEMS migration. The overall long-term clinical success rate was 94% after a mean follow-up of 13 months. In our experience, the placement of FCSEMSs is an effective and secure method of treating refractory postoperative BSs or BLs.

  9. Impending rupture of saphenous vein graft aneurysm with floating fractured bare metal stent treated by coil embolization and covered stent implantation.

    PubMed

    Kodama, Atsuko; Kurita, Tairo; Kato, Osamu; Suzuki, Takahiko

    2016-11-01

    Aneurysmal degeneration of a saphenous vein graft (SVG) is a rare, but potentially fatal complication of coronary artery bypass graft (CABG) surgery. In this case report, a patient that had undergone prior CABG surgery and bare metal stent (BMS) implantation at the site of a stenotic SVG lesion presented at our hospital with chest pain, and an SVG aneurysm was detected at the previous BMS implantation site. In addition, the implanted BMS was fractured and floating in the SVG aneurysm. The SVG aneurysm was successfully occluded by percutaneous intervention, using a combination of distal covered stent deployment at the site of the anastomosis between the native coronary artery and the SVG and proximal coil embolization of the aneurysm.

  10. Preparation of flexible organic solar cells with highly conductive and transparent metal-oxide multilayer electrodes based on silver oxide.

    PubMed

    Yun, Jungheum; Wang, Wei; Bae, Tae Sung; Park, Yeon Hyun; Kang, Yong-Cheol; Kim, Dong-Ho; Lee, Sunghun; Lee, Gun-Hwan; Song, Myungkwan; Kang, Jae-Wook

    2013-10-23

    We report that significantly more transparent yet comparably conductive AgOx films, when compared to Ag films, are synthesized by the inclusion of a remarkably small amount of oxygen (i.e., 2 or 3 atom %) in thin Ag films. An 8 nm thick AgOx (O/Ag=2.4 atom %) film embedded between 30 nm thick ITO films (ITO/AgOx/ITO) achieves a transmittance improvement of 30% when compared to a conventional ITO/Ag/ITO electrode with the same configuration by retaining the sheet resistance in the range of 10-20 Ω sq(-1). The high transmittance provides an excellent opportunity to improve the power-conversion efficiency of organic solar cells (OSCs) by successfully matching the transmittance spectral range of the electrode to the optimal absorption region of low band gap photoactive polymers, which is highly limited in OSCs utilizing conventional ITO/Ag/ITO electrodes. An improvement of the power-conversion efficiency from 4.72 to 5.88% is achieved from highly flexible organic solar cells (OSCs) fabricated on poly(ethylene terephthalate) polymer substrates by replacing the conventional ITO/Ag/ITO electrode with the ITO/AgOx/ITO electrode. This novel transparent electrode can facilitate a cost-effective, high-throughput, room-temperature fabrication solution for producing large-area flexible OSCs on heat-sensitive polymer substrates with excellent power-conversion efficiencies.

  11. Two-Phase Flow and Heat Transfer During Chilldown of a Simulated Flexible Metal Hose Using Liquid Nitrogen

    NASA Astrophysics Data System (ADS)

    Hu, Hong; Wijeratne, Thilan K.; Chung, J. N.

    2014-03-01

    For many industrial, medical and space technologies, cryogenic fluids play irreplaceable roles. When any cryogenic system is initially started, it must go through a transient chill down period prior to normal operation. Chilldown is the process of introducing the cryogenic liquid into the system, and allowing the system components to cool down to several hundred degrees below the ambient temperature. The chilldown process is an important initial stage before a system begins functioning. The objective of this paper is to investigate the chilldown process associated with a flexible hose that was simulated by a channel with saw-teeth inner wall surface structure in the current study. We have investigated the fundamental physics of the two-phase flow and quenching heat transfer during cryogenic chilldown inside the simulated flexible hose through flow visualization, data measurement and analysis. The flow pattern developed inside the channel was recorded by a high speed camera for flow pattern investigation. The experimental results indicate that the chilldown process that is composed of unsteady vapor-liquid two-phase flow and phase-change heat transfer is modified by the inner wall surface wavy structure. Based on the measurement of the channel wall temperature, the teeth structure and the associated cavities generally reduce the heat transfer efficiency compared to the straight hose. Furthermore, based on the measured data, a complete series of correlations on the heat transfer coefficient for each heat transfer regime was developed and reported.

  12. Hydroxyapatite Nanowires@Metal-Organic Framework Core/Shell Nanofibers: Templated Synthesis, Peroxidase-Like Activity, and Derived Flexible Recyclable Test Paper.

    PubMed

    Chen, Fei-Fei; Zhu, Ying-Jie; Xiong, Zhi-Chao; Sun, Tuan-Wei

    2017-03-08

    The templated synthesis of hydroxyapatite (HAP) nanowires@metal-organic framework (MOF) core/shell nanofibers (named HAP@MIL-100(Fe) nanofibers) is demonstrated. The ultralong hydroxyapatite nanowires are adopted as a hard template for the nucleation and growth of MIL-100(Fe) (a typical MOF) through the layer-by-layer method. The Coulombic and chelation interactions between Ca(2+) ions on the surface of the HAP nanowires and the COO(-) organic linkers of MIL-100(Fe) play key roles in the formation process. The as-prepared, water-stable HAP@MIL-100(Fe) nanofibers exhibit peroxidase-like activity toward the oxidation of different peroxidase substrates in the presence of H2 O2 , accompanied by a clear color change of the solution. Furthermore, a flexible, recyclable HAP@MIL-100(Fe) test paper is prepared successfully by using HAP@MIL-100(Fe) nanofibers as building blocks. A simple, low-cost, and sensitive colorimetric method for the detection of H2 O2 and glucose is established based on the as-prepared, flexible, recyclable HAP@MIL-100(Fe) test paper. More importantly, the HAP@MIL-100(Fe) test paper can be recovered easily for reuse by simply dipping in absolute ethanol for just 30 min, thus showing excellent recyclability. With its combination of advantages such as easy transportation, easy storage and use, rapid recyclability, light weight, and high flexibility, this HAP@MIL-100(Fe) test paper is promising for wide applications in various fields. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    PubMed

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

    2016-12-01

    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.

  14. Flexible supercapacitor fabrication by room temperature rapid laser processing of roll-to-roll printed metal nanoparticle ink for wearable electronics application

    NASA Astrophysics Data System (ADS)

    Yeo, Junyeob; Kim, Geonwoong; Hong, Sukjoon; Kim, Min Su; Kim, Daewon; Lee, Jinhwan; Lee, Ha Beom; Kwon, Jinhyeong; Suh, Young Duk; Kang, Hyun Wook; Sung, Hyung Jin; Choi, Jun-Ho; Hong, Won-Hwa; Ko, Jang Myoun; Lee, Seung-Hyun; Choa, Sung-Hoon; Ko, Seung Hwan

    2014-01-01

    We introduce a rapid and low-temperature laser annealing process of roll-to-roll (R2R) printed metal nanoparticle (NP) ink on a polymer substrate as an alternative to the conventional thermal annealing process using expensive and time consuming lengthy furnace. Due to the confined heating induced by the focused laser, R2R printed Ag NP film is selectively turned into a continuous conductive film without heating the whole substrate. As a result, the damage on the underlying polymer substrate, as well as the processing time required for the annealing, is significantly reduced by the laser annealing compared to the conventional thermal annealing. The resultant laser annealed Ag NP film also exhibits superior electrical and mechanical properties in comparison to the thermal annealed sample. The laser annealed Ag NP film is further applied to the flexible supercapacitor as the current collector in order to confirm the excellence of laser annealed Ag NP film in the fabrication of practical devices.

  15. pH- and metal-dependent structural diversity from mononuclear to two-dimensional polymers based on a flexible tricarboxylate ligand

    NASA Astrophysics Data System (ADS)

    Li, Chengjuan; Peng, Yanqiang; Wang, Suna; Zhang, Xianxi; Li, Yizhi; Dou, Jianmin; Li, Dacheng

    2011-07-01

    Six complexes based on a flexible tripodal ligand H 3TTTA (2,2',2″-[1,3,5-triazine-2,4,6-triyltris(thio)]tris-acetic acid) have been hydrothermally synthesized and structurally characterized. X-ray single-crystal diffractions reveal that they have rich structural chemistry: mononuclear, [Zn(HTTTA)(2,2'-bpy)(H 2O) 3] n ( 1); dimeric metallamacrocycle, [Zn(HTTTA)(2,2'-bipy)(H 2O)] n ( 2) and [Cd(HTTTA)(2,2'-bipy)(H 2O)·H 2O] n ( 3); two-dimensional networks with binodal (3,6)-connected CdI 2 topology based on linear trinuclear M3( μ2-CO 2) 4( μ2-CO 2) 2 SBUs (Secondary Building Units), [ M3(TTTA) 2(2,2'-bipy) 2(H 2O) m· nH 2O] n ( M=Zn· 4, m=0, n=4; Cd· 5 and Mn· 6, m=2; n=2). The value of pH and the metal ions has large influences on the resulting structures. The flexible tricarboxylic acid exhibits four coordination modes from monodentate to μ6-bridge. Fluorescence and magnetic properties of the complexes have also been investigated in details.

  16. One-shot deep-UV pulsed-laser-induced photomodification of hollow metal nanoparticles for high-density data storage on flexible substrates.

    PubMed

    Wan, Dehui; Chen, Hsuen-Li; Tseng, Shao-Chin; Wang, Lon A; Chen, Yung-Pin

    2010-01-26

    In this paper, we report a new optical data storage method: photomodification of hollow gold nanoparticle (HGN) monolayers induced by one-shot deep-ultraviolet (DUV) KrF laser recording. As far as we are aware, this study is the first to apply HGNs in optical data storage and also the first to use a recording light source for the metal nanoparticles (NPs) that is not a surface plasmon resonance (SPR) wavelength. The short wavelength of the recording DUV laser improved the optical resolution dramatically. We prepared HGNs exhibiting two absorbance regions: an SPR peak in the near-infrared (NIR) region and an intrinsic material extinction in the DUV region. A single pulse from a KrF laser heated the HGNs and transformed them from hollow structures to smaller solid spheres. This change in morphology for the HGNs was accompanied by a significant blue shift of the SPR peak. Employing this approach, we demonstrated its patterning ability with a resolving power of a half-micrometer (using a phase mask) and developed a readout method (using a blue-ray laser microscope). Moreover, we prepared large-area, uniform patterns of monolayer HGNs on various substrates (glass slides, silicon wafers, flexible plates). If this spectral recording technique could be applied onto thin flexible tapes, the recorded data density would increase significantly relative to that of current rigid discs (e.g., compact discs).

  17. Mechanismic investigation on the cleavage of phosphate monoester catalyzed by unsymmetrical macrocyclic dinuclear complexes: the selection of metal centers and the intrinsic flexibility of the ligand.

    PubMed

    Zhang, Xuepeng; Zhu, Yajie; Zheng, Xiaowei; Phillips, David Lee; Zhao, Cunyuan

    2014-04-07

    The hydrolysis mechanisms of phosphor-monoester monoanions NPP(-) (p-nitrophenyl phosphate) catalyzed by unsymmetrical bivalent dinuclear complexes are explored using DFT calculations in this report. Four basic catalyst-substrate binding modes are proposed, and two optional compartments for the location of the nucleophile-coordinated metal center are also considered. Five plausible mechanisms are examined in this computational study. Mechanisms 1, 2, and 3 employ an unsymmetrical dizinc complex. All three mechanisms are based on concerted SN2 addition-substitution pathways. Mechanism 1, which involves more electronegative oxygen atoms attached to the imine nitrogen atoms in the nucleophile-coordinated compartment, was found to be more competitive compared to the other two mechanisms. Mechanisms 4 and 5 are based on consideration of the substitution of the bivalent metal centers and the intrinsic flexibility of the ligand. Both mechanisms 4 and 5 are based on stepwise SN2-type reactions. Magnesium ions with hard base properties and more available coordination sites were found to be good candidates as a substitute in the M(II) dinuclear phosphatases. The reaction energy barriers for the more distorted complexes are lower than those of the less distorted complexes. The proper intermediate distance and a functional second coordination sphere lead to significant catalytic power in the reactions studied. More importantly, the mechanistic differences between the concerted and the stepwise pathways suggest that a better nucleophile with more available coordination sites (from either the metal centers or a functional second coordination sphere) favors concerted mechanisms for the reactions of interest. The results reported in the paper are consistent with and provide a reasonable interpretation for experimental observations in the literature. More importantly, our present results provide some practical suggestions for the selection of the metal centers and how to approach

  18. Assemblies of a new flexible multicarboxylate ligand and d10 metal centers toward the construction of homochiral helical coordination polymers: structures, luminescence, and NLO-active properties.

    PubMed

    Zang, Shuangquan; Su, Yang; Li, Yizhi; Ni, Zhaoping; Meng, Qingjin

    2006-01-09

    Hydro(solvo)thermal reactions between a new flexible multicarboxylate ligand of 2,2',3,3'-oxydiphthalic acid (2,2',3,3'-H(4)ODPA) and M(NO(3))(2).xH(2)O (M = Zn, x = 6; M = Cd, x = 4) in the presence of 4,4'-bipyridine (bpy) afford two novel homochiral helical coordination polymers [[Zn(2)(2,2',3,3'-ODPA)(bpy)(H(2)O)(3)].(H(2)O)(2) for 1 and [Cd(2)(2,2',3,3'-ODPA)(bpy)(H(2)O)(3)].(H(2)O)(2) for 2]. Though having almost the same chemical formula, they have different space groups (P2(1)2(1)2(1) for 1 and P2(1) for 2) and different bridging modes of the 2,2',3,3'-ODPA ligand. Two kinds of homochiral helices (right-handed) are found in both 1 and 2, each of which discriminates only one kind of crystallographical nonequivalent metal atom. 1 has a 2D metal-organic framework and can be seen as the unity of two parallel homochiral Zn1 and Zn2 helices, in which the nodes are etheric oxygen atoms. In contrast, 2 has a 3D metal-organic framework and consists of two partially overlapped homochiral Cd1 and Cd2 helices in the two dimensions. Moreover, metal-ODPA helices give a 2D chiral herringbone structural motif in both 1 and 2 in the two dimensions, which are further strengthened by the second ligand of bpy. Bulk materials for 1 and 2 all have good second-harmonic generation activity, approximately 1 and 0.8 times that of urea.

  19. Late Migration of Covered Metal Stent to the Stomach Through a Spontaneous Choledochoduodenal Fistula in a Patient With Malignant Biliary Obstruction.

    PubMed

    Katakura, Yoshiki; Asaki, Tsutoshi; Adachi, Seitaro; Yasuda, Ikuma; Toyomizu, Michifumi; Fukita, Yosho

    2012-06-01

    We report a case in which a spontaneous choledochoduodenal fistula occurred after biliary covered self-expanding metal stent (SEMS) placement and a late transfistula migration of the stent in a patient with malignant distal biliary obstruction. A partially covered WallFlex biliary stent (Boston Scientific) was appropriately implanted in the common bile duct. Subsequently the patient received chemotherapy with gemcitabine. After 7 months of the SEMS insertion, the patient presented with frequent vomiting. Abdominal computed tomography revealed the obstruction of the duodenal descending part and the migrated stent in the stomach. A choledochoduodenal fistula was observed endoscopically at the proximal point of the duodenal obstruction. These findings can cleanly account for the SEMS migration through the fistula. The mechanism of formation of the fistula is mostly associated with a mechanical contact between the bile duct wall and the SEMS edge, which is pushed up in the direction of the duodenum because of the enlargement of the primary tumor, finally penetrating through the duodenal wall. To our knowledge, this is an extreme unusual case, which has been unreported previously. Therefore, we emphasize the necessity of being alert to the potential for such complications in cases involving placement of SEMS for malignant biliary obstruction.

  20. Controllable growth of nanoscale conductive filaments in solid-electrolyte-based ReRAM by using a metal nanocrystal covered bottom electrode.

    PubMed

    Liu, Qi; Long, Shibing; Lv, Hangbing; Wang, Wei; Niu, Jiebin; Huo, Zongliang; Chen, Junning; Liu, Ming

    2010-10-26

    Resistive memory (ReRAM) based on a solid-electrolyte insulator is a promising nanoscale device and has great potentials in nonvolatile memory, analog circuits, and neuromorphic applications. The underlying resistive switching (RS) mechanism of ReRAM is suggested to be the formation and rupture of nanoscale conductive filament (CF) inside the solid-electrolyte layer. However, the random nature of the nucleation and growth of the CF makes their formation difficult to control, which is a major obstacle for ReRAM performance improvement. Here, we report a novel approach to resolve this challenge by adopting a metal nanocrystal (NC) covered bottom electrode (BE) to replace the conventional ReRAM BE. As a demonstration vehicle, a Ag/ZrO(2)/Cu NC/Pt structure is prepared and the Cu NC covered Pt BE can control CF nucleation and growth to provide superior uniformity of RS properties. The controllable growth of nanoscale CF bridges between Cu NC and Ag top electrode has been vividly observed by transmission electron microscopy (TEM). On the basis of energy-dispersive X-ray spectroscopy (EDS) and elemental mapping analyses, we further confirm that the chemical contents of the CF are mainly Ag atoms. These testing/metrology results are consistent with the simulation results of electric-field distribution, showing that the electric field will enhance and concentrate on the NC sites and control location and orientation of Ag CFs.

  1. Anatomy-shaped design of a fully-covered, biliary, self-expandable metal stent for treatment of benign distal biliary strictures

    PubMed Central

    Weigt, Jochen; Kandulski, Arne; Malfertheiner, Peter

    2016-01-01

    Background and study aims: The treatment success of benign biliary strictures with fully covered metal stents (CSEMS) is altered by high stent dislocation rates. We aimed to evaluate a new stent design to prevent dislocation. Patients and methods: Patients with benign biliary strictures were treated with a newly designed double-coned stent (dcSEMS). Mechanical analysis of the new stent was performed and it was compared with a cylindrical stent. Results: A total of 13 dcCSEMS were implanted in 11 patients (2 female, 9 male, median age 47, range 33 – 71). All patients had distal biliary strictures due to chronic pancreatitis. No stent migration occurred. In all but one patient the stents were removed. One patient refused stent extraction and was lost to follow up. Stent occlusion occurred twice leading to cholangitis in both cases. The duration of stent treatment was 170 days (range 61 – 254). After extraction only one patient had early recurrent stricture and received the same stent again. Three stents showed minimal tissue granulation at the papilla. One stent presented ingrowth at the proximal end and was removed after implantation of a second fully covered stent. Mechanical examination revealed significantly lower radial expansion force of the new stent as compared to the cylindrical stent. Conclusions: The new stent design has a low rate of migration. Biomechanical properties may explain this effect. PMID:26793789

  2. Metal Nanowires: Synthesis, Processing, and Structure-Property Relationships in the Context of Flexible Transparent Conducting Films

    NASA Astrophysics Data System (ADS)

    Rathmell, Aaron R.

    The demand for flat-panel televisions, e-readers, smart-phones, and touch-screens has been increasing over the past few years and will continue to increase for the foreseeable future. Each of these devices contains a transparent conductor, which is usually indium tin oxide (ITO) because of its high transparency and low sheet resistance. ITO films, however, are brittle, expensive, and difficult to deposit, and because of these problems, alternative transparent electrodes are being studied. One cheap and flexible alternative to ITO is films of randomly oriented copper nanowires. We have developed a synthesis to make long, thin, and well-dispersed copper nanowires that can be suspended in an ink and coated onto a substrate to make flexible transparent films. These films are then made conductive by annealing in a hydrogen atmosphere or by a solution processing technique that can be done in air at room temperature. The resulting flexible transparent conducting films display transparencies and sheet resistance values comparable to ITO. Since it is well known that copper oxidizes, we also developed a synthesis to coat the copper nanowires with a layer of nickel in solution. Our measurements indicated that copper nanowires would double their sheet resistance in 3 months, but the sheet resistance of cupronickel nanowire films containing 20 mole% nickel will double in about 400 years. The addition of nickel to the copper nanowires also gave the film a more neutral grey appearance. The nickel coating can also be applied to the copper nanowires after the film is formed via an electroless plating method. To further optimize the properties of our transparent conductors we developed a framework to understand how the dimensions and area coverage of the nanowires affect the overall film properties. To quantify the effect of length on the sheet resistance and transmittance, wires with different lengths but the same diameter were synthesized to make transparent conducting films and

  3. [The application of Y-shaped self-expandable covered metal stents in the thoracostomach-airway fistula: a single center, 11 years experience].

    PubMed

    Fang, Yi; Li, Tengfei; Han, Xinwei; Wu, Gang; Ren, Jianzhuang; Ren, Kewei; Lu, Huibin; Zhang, Quanhui; Li, Zongming

    2015-08-01

    To investigate the clinical feasibility and efficacy of Y-shaped self-expandable covered metal stents (Y-stents) in the management of thoracostomach-airway fistula. Retrospective analysis was performed for 108 patients treated for thoracostomach-airway fistula with Y-shaped self-expandable coated metal stents between April 2003 and October 2014. Y-stents were designed based on the dimensions of trachea and bronchus and sites of the fistula and then were inserted under DSA monitoring. There were 65 cases with single big Y-stent placement, 26 cases with single small Y-stent placement, 23 cases with double Y-stents placement, and 1 case with 3 Y-stents placement. Stent implantation was successfully accomplished with single manipulation in all patients. Complete occlusion of the fistula was obtained in 104 patients after the primary manipulation, and 4 patients required a secondary manipulation where a double Y-stents was inserted because of failure of primary manipulate. Ninety-two patients completed the follow-up , while 16 were lost. Fifty-nine patients died while 33 were alive with marked improvement in their quality of life. The placement of Y-stents can effectively occlude the thoracostomach-airway fistula in patients who had had the esophageal tumors resected. The technique is not only feasible but reliable to improve the quality of life of the patients.

  4. Flexible reusable mandrels

    NASA Technical Reports Server (NTRS)

    Willden, Kurtis S. (Inventor)

    1995-01-01

    A reusable laminate mandrel which is unaffected by extreme temperature changes. The flexible laminate mandrel is comprised of sheets stacked to produce the required configuration, a cover wrap that applies pressure to the mandrel laminate, maintaining the stack cross-section. Then after use, the mandrels can be removed, disassembled, and reused. In the method of extracting the flexible mandrel from one end of a composite stiffener, individual ones of the laminae of the flexible mandrel or all are extracted at the same time, depending on severity of the contour.

  5. Production of flexible metal matrix composites reinforced with continuous Si-Ti-C-O fibers by atmospheric plasma spraying

    NASA Astrophysics Data System (ADS)

    Waku, Y.; Nakagawa, N.; Ohsora, Y.; Takahashi, T.; Shimizu, K.; Yamamura, T.; Ohmori, A.

    1992-06-01

    An experiment is conducted to fabricate a flexible prepreg sheet with a continuous Si-Ti-C-O fiber by means of an air-plasma spraying method for use as an MMC plate. Plasma spraying is conducted under atmospheric conditions, and the prepreg and MMC sheets are investigated by means of a three-point flexural test and Auger electron spectroscopy to study strength and oxidation qualities. The oxidation layer is found to be about 200 A in depth, and the longitudinal and transverse flexural strengths of a unidirectionally reinforced MMC plate fabricated by hot pressing at 660 C are given as 1.0 and 0.25 GPa, respectively. The technique outlined is shown to be useful for developing squeeze-cast MMCs reinforced with Si-Ti-C-O that have high specific strength, specific modulus, and heat resistance.

  6. Production of flexible metal matrix composites reinforced with continuous Si-Ti-C-O fibers by atmospheric plasma spraying

    SciTech Connect

    Waku, Y.; Nakagawa, N.; Ohsora, Y.; Takahashi, T.; Shimizu, K.; Yamamura, T.; Ohmori, A. Osaka University, )

    1992-06-01

    An experiment is conducted to fabricate a flexible prepreg sheet with a continuous Si-Ti-C-O fiber by means of an air-plasma spraying method for use as an MMC plate. Plasma spraying is conducted under atmospheric conditions, and the prepreg and MMC sheets are investigated by means of a three-point flexural test and Auger electron spectroscopy to study strength and oxidation qualities. The oxidation layer is found to be about 200 A in depth, and the longitudinal and transverse flexural strengths of a unidirectionally reinforced MMC plate fabricated by hot pressing at 660 C are given as 1.0 and 0.25 GPa, respectively. The technique outlined is shown to be useful for developing squeeze-cast MMCs reinforced with Si-Ti-C-O that have high specific strength, specific modulus, and heat resistance. 18 refs.

  7. Framework-Flexibility Driven Selective Sorption of p-Xylene over Other Isomers by a Dynamic Metal-Organic Framework

    PubMed Central

    Mukherjee, Soumya; Joarder, Biplab; Manna, Biplab; Desai, Aamod V.; Chaudhari, Abhijeet K.; Ghosh, Sujit K.

    2014-01-01

    Chemical separation has great importance in industrial applications. Separation of xylene isomers still prevails to be one of the most important challenges in chemical industry, due to the large amount of commercial use of p-xylene in the production of beverage bottles, fibers and films. A novel Zn(II)-based dynamic coordination framework based on flexible ether-linkage, exhibiting selective adsorption of p-Xylene over its congener C8-alkyl aromatic isomers at ambient conditions is reported. Notably, no dynamic structure based MOF compound is known in the literature which shows clear preference of p-xylene over other isomers. This type of framework-breathing and guest-induced reversible solid-state structural transformations with unique adsorption selectivity can be exploited purposefully to develop smart functional host materials capable of industrially important chemical separations. PMID:25041900

  8. ULTRA BARRIER TOPSHEET (UBT) FOR FLEXIBLE PHOTOVOLTAICS

    SciTech Connect

    DeScioli, Derek

    2013-06-01

    This slide-show presents 3M photovoltaic-related products, particularly flexible components. Emphasis is on the 3M Ultra Barrier Solar Films. Topics covered include reliability and qualification testing and flexible photovoltaic encapsulation costs.

  9. Cover Crops

    USDA-ARS?s Scientific Manuscript database

    Cover crops are a beneficial tool for use in conservation tillage systems. Cover crop residues reduce soil erosion from water and wind, increase soil water availability for subsequent crops, enhance soil organic matter and biological activity, and can decrease labor and energy inputs. Cover crop...

  10. All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Ko, Seung H.; Pan, Heng; Grigoropoulos, Costas P.; Luscombe, Christine K.; Fréchet, Jean M. J.; Poulikakos, Dimos

    2007-08-01

    All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

  11. Ceramic barrier layers for flexible thin film solar cells on metallic substrates: a laboratory scale study for process optimization and barrier layer properties.

    PubMed

    Delgado-Sanchez, Jose-Maria; Guilera, Nuria; Francesch, Laia; Alba, Maria D; Lopez, Laura; Sanchez, Emilio

    2014-11-12

    Flexible thin film solar cells are an alternative to both utility-scale and building integrated photovoltaic installations. The fabrication of these devices over electrically conducting low-cost foils requires the deposition of dielectric barrier layers to flatten the substrate surface, provide electrical isolation between the substrate and the device, and avoid the diffusion of metal impurities during the relatively high temperatures required to deposit the rest of the solar cell device layers. The typical roughness of low-cost stainless-steel foils is in the hundred-nanometer range, which is comparable or larger than the thin film layers comprising the device and this may result in electrical shunts that decrease solar cell performance. This manuscript assesses the properties of different single-layer and bilayer structures containing ceramics inks formulations based on Al2O3, AlN, or Si3N4 nanoparticles and deposited over stainless-steel foils using a rotogravure printing process. The best control of the substrate roughness was achieved for bilayers of Al2O3 or AlN with mixed particle size, which reduced the roughness and prevented the diffusion of metals impurities but AlN bilayers exhibited as well the best electrical insulation properties.

  12. High Efficiency Cu(In,Ga)Se2 Flexible Solar Cells Fabricated by Roll-to-Roll Metallic Precursor Co-sputtering Method

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Hollars, Dennis R.; Kanicki, Jerzy

    2013-09-01

    We report on a Cu(In,Ga)Se2 (CIGS) solar cell fabricated on flexible stainless steel substrate by a low cost mass production roll-to-roll process. Fabricated device has a high energy conversion efficiency of 14%, with short circuit current density (Jsc) of 36.6 mA cm-2 and open circuit voltage (Voc) of 0.55 V. A two-dimensional (2D) simulation model for CIGS solar cell design and optimization was proposed. Opto-electrical properties showed that both experimental and simulated results are consistent with each other. The photons absorber in CIGS solar cells was prepared by co-sputtering metallic precursors of In and CuGa followed by thermal annealing in Se vapor. The device chemical properties were analyzed by secondary ion mass spectrometry (SIMS) and transmission/scan electron microscopy (TEM/SEM). Indium and gallium interdiffusions were observed during the growth of film, forming a band grading in CIGS layer. Accumulation of In at the top CIGS surface, resulting in a low bandgap, was responsible for the limited output open circuit voltage. Nano-scale voids were observed in the grown CIGS layer. A model based on Kirkendal effect and interdiffusion of atoms during selenization is developed to explain the formation mechanism of these voids. Na and K incorporation as well as metallic impurities diffusion are also discussed.

  13. Five novel transition metal coordination polymers with 2D/3D framework structure based on flexible H{sub 2}tzda and ancillary ligand bpe

    SciTech Connect

    Wang Yuting; Xu Yan; Fan Yaoting; Hou Hongwei

    2009-10-15

    Five new transition metal coordination polymers based on H{sub 2}tzda and co-ligand bpe, {l_brace}[M(tzda)(bpe)].H{sub 2}O{r_brace}{sub n} [M=Zn(1), Cd(2), Mn(3), Co(4)] and [Ni{sub 2}(tzda){sub 2}(bpe){sub 2}(H{sub 2}O)]{sub n} (5) [H{sub 2}tzda=(1,3,4-thiadiazole-2,5-diyldithio)diacetic acid, bpe=1,2-bis(4-pyridyl)ethane], have been hydrothermally synthesized and structurally characterized. Compounds 1-4 feature a 2D-layered architecture generated from [M(tzda)]{sub n} moiety with double-chain structure cross-linking bpe spacers. However, the conformations bpe adopts in 3 and 4 are different from those in 1 and 2 due to the rotation of C-C single bond in bpe. Polymer 5 exhibits an interesting 3D porous framework with 2-fold interpenetration, in which intriguing 1D double helix chains are observed. The photoluminescence properties of 1 and 2 in the solid-state at room temperature are investigated. In addition, variable-temperature magnetic data show weak antiferromagnetic behavior in 3-5. - Graphical abstract: Five new transition metal coordination polymers based on flexible H{sub 2}tzda and bpe have been hydrothermally synthesized and characterized by X-ray diffraction, luminescent emission spectra and low-temperature magnetic measurements, respectively.

  14. Metal-assisted exfoliation (MAE): green process for transferring graphene to flexible substrates and templating of sub-nanometer plasmonic gaps (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zaretski, Aliaksandr V.; Marin, Brandon C.; Moetazedi, Herad; Dill, Tyler J.; Jibril, Liban; Kong, Casey; Tao, Andrea R.; Lipomi, Darren J.

    2015-09-01

    This paper describes a new technique, termed "metal-assisted exfoliation," for the scalable transfer of graphene from catalytic copper foils to flexible polymeric supports. The process is amenable to roll-to-roll manufacturing, and the copper substrate can be recycled. We then demonstrate the use of single-layer graphene as a template for the formation of sub-nanometer plasmonic gaps using a scalable fabrication process called "nanoskiving." These gaps are formed between parallel gold nanowires in a process that first produces three-layer thin films with the architecture gold/single-layer graphene/gold, and then sections the composite films with an ultramicrotome. The structures produced can be treated as two gold nanowires separated along their entire lengths by an atomically thin graphene nanoribbon. Oxygen plasma etches the sandwiched graphene to a finite depth; this action produces a sub-nanometer gap near the top surface of the junction between the wires that is capable of supporting highly confined optical fields. The confinement of light is confirmed by surface-enhanced Raman spectroscopy measurements, which indicate that the enhancement of the electric field arises from the junction between the gold nanowires. These experiments demonstrate nanoskiving as a unique and easy-to-implement fabrication technique that is capable of forming sub-nanometer plasmonic gaps between parallel metallic nanostructures over long, macroscopic distances. These structures could be valuable for fundamental investigations as well as applications in plasmonics and molecular electronics.

  15. Novel metal-organic and supramolecular 3D frameworks constructed from flexible biphenyl-2,5,3‧-tricarboxylate blocks: Synthesis, structural features and properties

    NASA Astrophysics Data System (ADS)

    You, Ao; Li, Yu; Zhang, Ze-Min; Zou, Xun-Zhong; Gu, Jin-Zhong; Kirillov, Alexander M.; Chen, Jin-Wei; Chen, Yun-Bo

    2017-10-01

    Biphenyl-2,5,3‧-tricarboxylic acid (H3L) was selected as an unexplored tricarboxylate building block and applied for the hydrothermal synthesis of three novel coordination compounds, namely a 0D tetramer [Co4(HL)2(μ3-HL)2(phen)6(H2O)2]·3H2O (1) and two 3D metal-organic frameworks (MOFs) [Cd3(μ5-L)(μ6-L)(py)(μ-H2O)2(H2O)]n·H2O (2) and [Zn3(μ4-L)2(2,2‧-bpy)(μ-4,4‧-bpy)]n·2H2O (3). These products were easily generated in aqueous medium from the corresponding metal(II) chlorides, H3L, and various N-donor ancillary ligands, selected from 1,10-phenanthroline (phen), pyridine (py), 2,2‧-bipyridine (2,2‧-bpy), and 4,4‧-bipyridine (4,4‧-bpy). Compounds 1-3 were isolated as stable crystalline solids and were fully characterized by IR and UV-vis spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a discrete tetracobalt(II) structure, which is extended into a 3D H-bonded network with the pcu topology. In contrast, MOF 2 discloses a very complex trinodal 4,5,12-connected net with an undocumented topology, while MOF 3 features the nce/I topological framework. The magnetic (for 1) and luminescence (for 2 and 3) properties were also studied and discussed. The present study thus widens a still very limited family of metal-organic and supramolecular frameworks driven by flexible biphenyl-2,5,3‧-tricarboxylate building blocks.

  16. Multicenter trial evaluating the use of covered self-expanding metal stents in benign biliary strictures: time to revisit our therapeutic options?

    PubMed

    Kahaleh, Michel; Brijbassie, Alan; Sethi, Amrita; Degaetani, Marisa; Poneros, John M; Loren, David E; Kowalski, Thomas E; Sejpal, Divyesh V; Patel, Sandeep; Rosenkranz, Laura; McNamara, Kevin N; Raijman, Isaac; Talreja, Jayant P; Gaidhane, Monica; Sauer, Bryan G; Stevens, Peter D

    2013-09-01

    Covered self-expanding metal stents are being used more frequently in benign biliary strictures (BBS). We report the results of a multicenter study with fully covered self-expanding metal stent (FCSEMS) placement for the management of BBS. : To prospectively evaluate the efficacy and safety of FCSEMS in the management of BBS. Patients with BBS from 6 tertiary care centers who received FCSEMS with flared ends between April 2009 and October 2010 were included in this retrospective study.Efficacy was measured after removal of FCSEMS by evaluating stricture resolution on the basis of symptom resolution, imaging, laboratory studies, and/or choledochoscopy at removal. Safety profile was evaluated by assessing postprocedural complications. A total of 133 patients (78, 58.6% males) with a mean age of 59.2±14.8 years with BBS received stents. Of the 133 stents placed, 97 (72.9%) were removed after a mean stent duration of 95.5±48.7 days. Stricture resolution after FCSEMS removal was as follows: postsurgical, 11/12 (91.6%); gallstone-related disease, 16/19 (84.2%); chronic pancreatitis, 26/31 (80.7%); other etiology, 4/5 (80.0%); and anastomotic strictures, 19/31(61.2%). Ninety-four patients were included in the logistic regression analyses. Patients who had indwelling stents for >90 days were 4.3 times more likely to have resolved strictures [odds ratio, 4.3 (95% confidence interval, 1.24-15.09)] and patients with nonmigrated stents were 5.4 times more likely to have resolved strictures [odds ratio, 5.4 (95% confidence interval, 1.001-29.29)]. FCSEMS for BBS had an acceptable rate of stricture resolution for postsurgical strictures, gallstone-related strictures, and those due to chronic pancreatitis. Predictors for stricture resolution include longer indwell time and absence of migration. Further study is warranted to assess long-term efficacy in a prospective manner with longer than 3-month time of stent indwelling time.

  17. Arene guest selectivity and pore flexibility in a metal-organic framework with semi-fluorinated channel walls

    NASA Astrophysics Data System (ADS)

    Smith, Rebecca; Vitórica-Yrezábal, Iñigo J.; Hill, Adrian; Brammer, Lee

    2017-01-01

    A metal-organic framework (MOF) with one-dimensional channels of approximately hexagonal cross-section [Ag2(O2CCF2CF2CO2)(TMP)] 1 (TMP =2,3,5,6-tetramethylpyrazine) has been synthesized with MeOH filling the channels in its as-synthesized form as [Ag2(O2CCF2CF2CO2)(TMP)]·n(MeOH) 1-MeOH (n = 1.625 by X-ray crystallography). The two types of ligand connect columns of Ag(I) centres in an alternating manner, both around the channels and along their length, leading to an alternating arrangement of hydrocarbon (C-H) and fluorocarbon (C-F) groups lining the channel walls, with the former groups projecting further into the channel than the latter. MeOH solvent in the channels can be exchanged for a variety of arene guests, ranging from xylenes to tetrafluorobenzene, as confirmed by gas chromatography, 1H nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis and 13C cross-polarization magic angle spinning NMR spectroscopy. Alkane and perfluoroalkane guests, however, do not enter the channels. Although exhibiting some stability under a nitrogen atmosphere, sufficient to enable crystal structure determination, the evacuated MOF 1 is unstable for periods of more than minutes under ambient conditions or upon heating, whereupon it undergoes an irreversible solid-state transformation to a non-porous polymorph 2, which comprises Ag2(O2CCF2CF2CO2) coordination layers that are pillared by TMP ligands. This transformation has been followed in situ by powder X-ray diffraction and shown to proceed via a crystalline intermediate. This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'.

  18. Comparison of the influence of plastic and fully covered metal biliary stents on the accuracy of EUS-FNA for the diagnosis of pancreatic cancer.

    PubMed

    Siddiqui, Ali A; Fein, Michael; Kowalski, Thomas E; Loren, David E; Eloubeidi, Mohamad A

    2012-09-01

    Prior studies have reported that the presence of prior biliary stent may interfere with EUS visualization of pancreatic tumors. We aimed to compare the influence of the biliary plastic and fully covered self-expanding metal stents (CSEMS) on the accuracy of EUS-FNA cytology in patients with solid pancreatic masses. We conducted a retrospective study evaluating 677 patients with solid pancreatic head/uncinate lesions and a previous biliary stent in whom EUS-FNA was performed. The patients were stratified into two groups: (1) those with a plastic stents and (2) those with CSEMS. Performance characteristics of EUS-FNA including the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were compared between the two groups. The frequency of obtaining an adequate cytology by EUS-FNA was similar in both the CSEMS group and the plastic stent group (97 vs. 97.1 % respectively; p = 1.0). The sensitivity, specificity, and accuracy of EUS-FNA was not significantly different between patients with CSEMS and plastic stents (96.8, 100, 100 % and 97.3, 98, 99.8 %, respectively). The negative predictive value for EUS-FNA was lower in the CSEMS group compared to the plastic stent group (66.6 vs. 78.1 % respectively; p = 0.42). There was one false-positive cytology in the plastic stent group compared to none in the CSEMS group. In a retrospective cohort trial, EUS-FNA was found to be highly accurate and safe in diagnosing patients with suspected pancreatic cancer, even in the presence of a plastic or metallic biliary stent. The presence of a stent did not contribute to a higher false-positive cytology rate.

  19. Flexible Ablators

    NASA Technical Reports Server (NTRS)

    Stackpoole, Margaret M. (Inventor); Ghandehari, Ehson M. (Inventor); Thornton, Jeremy J. (Inventor); Covington, Melmoth Alan (Inventor)

    2017-01-01

    A low-density article comprising a flexible substrate and a pyrolizable material impregnated therein, methods of preparing, and devices using the article are disclosed. The pyrolizable material pyrolizes above 350 C and does not flow at temperatures below the pyrolysis temperature. The low-density article remains flexible after impregnation and continues to remain flexible when the pyrolizable material is fully pyrolized.

  20. A fully covered self-expandable metal stent anchored by a 10-Fr double pigtail plastic stent: an effective anti-migration technique

    PubMed Central

    Katsinelos, Panagiotis; Lazaraki, Georgia; Gkagkalis, Stergios; Chatzimavroudis, Grigoris; Anastasiadou, Kiriaki; Georgakis, Nikos; Giouleme, Olga; Zavos, Christos; Kountouras, Jannis

    2017-01-01

    Background Fully covered self-expandable metal stents (FCSEMS) have been used successfully in the treatment of malignant and benign biliary strictures. However, stent migration is a major complication. We investigated the efficacy of anchoring FCSEMS with a 10-Fr double-pigtail plastic stent to prevent migration in patients with biliary strictures. Methods Between January 2012 and May 2013, 10 patients with malignant biliary strictures and one patient with a suprapapillary benign biliary stenosis were enrolled in the study. The primary endpoint of the study was to record the migration rate of FCSEMS. Results The placement of FCSEMSs and the anchoring with a 10-Fr double-pigtail plastic stent were successful in all patients. During a median follow-up period of eight months, proximal or distal migration of FCSEMS was not observed. No procedural complications related to the placement of FCSEMS and/or the anchoring plastic stent were recorded. Conclusions The placement of an anchoring 10-Fr double-pigtail stent is a simple and effective anti-migration technique for FCSEMS in patients with malignant biliary strictures. PMID:28042247

  1. Biodegradable biliary stents have a different effect than covered metal stents on the expression of proteins associated with tissue healing in benign biliary strictures.

    PubMed

    Siiki, Antti; Jesenofsky, Ralf; Löhr, Matthias; Nordback, Isto; Kellomäki, Minna; Gröhn, Heidi; Mikkonen, Joonas; Sand, Juhani; Laukkarinen, Johanna

    2016-07-01

    Benign biliary strictures (BBS) are primarily treated endoscopically with covered self-expandable metal stents (CSEMS). Biodegradable biliary stents (BDBS) may be the future of endoscopic therapy of BBS. The aim was to assess the expression of proteins related to tissue healing in BBS compared with the intact bile duct (BD), and to study the protein expression after therapy with CSEMS or BDBS. Pigs with ischemic BBS were endoscopically treated either with BDBS or CSEMS. Samples were harvested from pigs with intact BD (n = 5), untreated BBS (n = 5), and after six months of therapy with BDBS (n = 4) or CSEMS (n = 5) with subsequent histologic analysis. Two-dimensional electrophoresis with protein identification was performed to evaluate protein expression patterns. In BBS, the expression of galectin-2 and annexin-A4 decreased, compared to intact BD. Treatment with biodegradable stents normalized galectin-2 level; with CSEMS therapy it remained low. Transgelin expression of intact BD and BBS remained low after BDBS treatment but increased after CSEMS therapy. Histologic analysis did not show unwanted foreign body reaction or hyperplasia in the BD in either group. The expression of proteins related to tissue healing in BBS is different after treatment with biodegradable stents and CSEMS. Treatment with biodegradable stents may bring protein expression towards what is seen in intact BD. BDBS seem to have a good biocompatibility.

  2. Covering Crime.

    ERIC Educational Resources Information Center

    Gest, Ted; Krajicek, David; Hackney, Suzette; Moore, Melissa

    2003-01-01

    Presents four brief articles on covering crime. Notes that reporting on crimes requires special skills for student reporters, editors, and photographers. Explains how to gain access to scenes, to develop journalistic ethics, and how to cover crime and its victims. Discusses the relation of race and ethnic issues to crime, and how visual…

  3. Sustained Benefit at 2 Years for Covered Stents Versus Bare-Metal Stents in Long SFA Lesions: The VIASTAR Trial

    SciTech Connect

    Lammer, Johannes E-mail: johannes.lammer@meduniwien.ac.at; Zeller, Thomas; Hausegger, Klaus A.; Schaefer, Philipp J.; Gschwendtner, Manfred; Mueller-Huelsbeck, Stefan; Rand, Thomas; Funovics, Martin Wolf, Florian; Rastan, Aljoscha; Gschwandtner, Michael; Puchner, Stefan; and others

    2015-02-15

    PurposeThe hypothesis that covered stents are superior to bare-metal stents (BMS) in long femoropopliteal artery disease was tested. The one-year results of the VIASTAR trial revealed a patency benefit of covered stents in the treatment-per-protocol (TPP) analysis only.MethodsA prospective, randomized, single-blind, multicenter study evaluated 141 patients with symptomatic peripheral arterial disease (PAD) after treatment with heparin-bonded covered stents (VIABAHN{sup ®} Endoprosthesis) or BMS. Clinical outcomes and patency rates were assessed at 1, 6, 12, and 24 months. Mean lesion length was 19.0 ± 6.3 cm in the VIABAHN{sup ®} versus 17.3 ± 6.6 cm in the BMS group.ResultsThe 24-month primary patency rates in the VIABAHN{sup ®} and BMS group were: intention-to-treat 63.1 (95 % CI 0.52–0.76) versus 41.2 % (95 % CI 0.29–0.57; log rank p = 0.04) and TPP 69.4 (95 % CI 0.58–0.83) versus 40.0 % (95 % CI 0.28–0.56; log rank p = 0.004). Freedom from target-lesion-revascularization (TLR) was 79.4 (95 % CI 0.70–0.90) versus 73.0 % (95 % CI 0.63–0.85) for VIABAHN{sup ®} versus BMS (log rank p = 0.37). For the TPP group in lesions ≥20 cm, the 24-month patency rates were 65.2 (95 % CI 0.50–0.85) versus 26.7 % (95 % CI 0.12–0.59; log rank p = 0.004) for VIABAHN{sup ®} versus BMS, and freedom from TLR was 80.0 (95 % CI 0.68–0.94) versus 61.9 % (95 % CI 0.44–0.87; log rank p = 0.13). The ankle brachial index was 0.89 ± 0.18 versus 0.91 ± 0.17 (p = 0.76) at 24-month in the VIABAHN{sup ®} versus the BMS group, respectively.ConclusionAt 24-month, this trial in PAD patients with long femoropopliteal lesions demonstrated a significantly improved primary patency rate for heparin-bonded covered stents compared to BMS, however, without a significant impact on clinical outcomes and TLR rate (Reg. Nr. ISRCTN48164244)

  4. Real-Time Detection of Traces of Benzaldehyde in Benzyl Alcohol as a Solvent by a Flexible Lanthanide Microporous Metal-Organic Framework.

    PubMed

    Zhang, Huan; Chen, Diming; Ma, Huili; Cheng, Peng

    2015-10-26

    Luminescent 3D lanthanide metal-organic framework (Ln-MOF) {[Tb2 (TATAB)2 ]⋅4 H2 O⋅6 DMF}n (1) was synthesized under solvothermal conditions by using flexible ligand 4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB). A phase transition was observed between low temperature and room temperature. The luminescence of 1 could be enhanced by formaldehyde and quenched efficiently by trace amounts of benzaldehyde in solvents such as benzyl alcohol (0.01-2.0 vol %) and ethanol (0.01-2.5 vol %). This is the first use of a Ln-MOF as chemical sensor for both formaldehyde and benzaldehyde. The high sensitivity and selectivity of the luminescence response of 1 to benzaldehyde allows it to be used as an excellent sensor for identifying benzaldehyde and provides a simple and convenient method for detecting traces of benzaldehyde in benzyl alcohol based injections. This work establishes a new strategy for detection of benzaldehyde in benzyl alcohol by luminescent MOFs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Elongated solid electrolyte cell configurations and flexible connections therefor

    DOEpatents

    Reichner, Philip

    1989-01-01

    A flexible, high temperature, solid oxide electrolyte electrochemical cell stack configuration is made, comprising a plurality of flattened, elongated, connected cell combinations 1, each cell combination containing an interior electrode 2 having a top surface and a plurality of interior gas feed conduits 3, through its axial length, electrolyte 5 contacting the interior electrode and exterior electrode 8 contacting electrolyte, where a major portion of the air electrode top surface 7 is covered by interconnection material 6, and where each cell has at least one axially elongated, electronically conductive, flexible, porous, metal fiber felt material 9 in electronic connection with the air electrode 2 through contact with a major portion of the interconnection material 6, the metal fiber felt being effective as a shock absorbent body between the cells.

  6. Elongated solid electrolyte cell configurations and flexible connections therefor

    DOEpatents

    Reichner, P.

    1989-10-17

    A flexible, high temperature, solid oxide electrolyte electrochemical cell stack configuration is made, comprising a plurality of flattened, elongated, connected cell combinations, each cell combination containing an interior electrode having a top surface and a plurality of interior gas feed conduits, through its axial length, electrolyte contacting the interior electrode and exterior electrode contacting electrolyte, where a major portion of the air electrode top surface is covered by interconnection material, and where each cell has at least one axially elongated, electronically conductive, flexible, porous, metal fiber felt material in electronic connection with the air electrode through contact with a major portion of the interconnection material, the metal fiber felt being effective as a shock absorbent body between the cells. 4 figs.

  7. Short-term stenting using fully covered self-expandable metal stents for treatment of refractory biliary leaks, postsphincterotomy bleeding, and perforations.

    PubMed

    Canena, Jorge; Liberato, Manuel; Horta, David; Romão, Carlos; Coutinho, António

    2013-01-01

    Fully covered self-expandable metal stents (FCSEMS) have been used as a rescue therapy for several benign biliary tract conditions (BBC). Long-term stent placement commonly occurs, and prolonged FCSEMS placement is associated with the majority of the complications reported. This study evaluated the duration of stenting and the efficacy and safety of temporary FCSEMS placement for three BBCs: refractory biliary leaks, postsphincterotomy bleeding, and perforations. This was a retrospective case series with long-term follow-up of 25 patients who underwent FCSEMS placement for BBCs. This study included 17 patients with postcholecystectomy refractory biliary leaks who had previously undergone unsuccessful sphincterotomy and plastic stent placement, 4 patients with difficult-to-control postsphincterotomy bleeding, and 4 patients with a perforation following endoscopic sphincterotomy. Stents were removed according to clinical evidence of problem resolution. The review included stenting duration, safe FCSEMS removal, clinical efficacy, complications, and long-term outcomes. During the follow-up period, ERCP and cholangioscopy procedures were performed to exclude the possibility of bile duct lesion development. Complete resolution of the initial condition was achieved in all patients. Patients with biliary leaks had a median stent duration time of 16 days (range 7-28 days). Patients with bleeding had stents removed after a median time of 6 days (range 3-15 days). Patients with perforations had their stents removed after a median time of 29.5 days (range 21-30 days). There were no complications related to stenting. Temporary placement of a FCSEMS for 30 days or less is an effective rescue therapy for refractory biliary leaks, difficult-to-control post-endoscopic sphincterotomy bleeding, and perforations. Duration of stenting should be different for each type of condition. Stents can be safely removed, and short-term stenting is associated with the absence of early and late

  8. A US Multicenter Study of Safety and Efficacy of Fully Covered Self-Expandable Metallic Stents in Benign Extrahepatic Biliary Strictures.

    PubMed

    Saxena, Payal; Diehl, David L; Kumbhari, Vivek; Shieh, Frederick; Buscaglia, Jonathan M; Sze, Wilson; Kapoor, Sumit; Komanduri, Srinadh; Nasr, John; Shin, Eun Ji; Singh, Vikesh; Lennon, Anne Marie; Kalloo, Anthony N; Khashab, Mouen A

    2015-11-01

    Endoscopic therapy is considered first line for management of benign biliary strictures (BBSs). Placement of plastic stents has been effective but limited by their short-term patency and need for repeated procedures. Fully covered self-expandable metallic stents (FCSEMSs) offer longer-lasting biliary drainage without the need for frequent exchanges. The aim of this study was to assess the efficacy and safety of FCSEMS in patients with BBS. A retrospective review of all patients who underwent ERCP and FCSEMS placement at five tertiary referral US hospitals was performed. Stricture resolution and adverse events related to ERCP and/or stenting were recorded. A total of 123 patients underwent FCSEMS placement for BBS and 112 underwent a subsequent follow-up ERCP. The mean age was 62 years (±15.6), and 57% were males. Stricture resolution occurred in 81% of patients after a mean of 1.2 stenting procedures (mean stent dwell time 24.4 ± 2.3 weeks), with a mean follow-up of 18.5 months. Stricture recurrence occurred in 5 patients, and 3 patients required surgery for treatment of refractory strictures. Stent migration (9.7%) was the most common complication, followed by stent occlusion (4.9%), cholangitis (4.1%), and pancreatitis (3.3%). There was one case of stent fracture during removal, and one stent could not be removed. There was one death due to cholangitis. Majority of BBS can be successfully managed with 1-2 consecutive FCSEMS with stent dwell time of 6 months.

  9. Randomized multicenter study of multiple plastic stents vs. covered self-expandable metallic stent in the treatment of biliary stricture in chronic pancreatitis.

    PubMed

    Haapamäki, Carola; Kylänpää, Leena; Udd, Marianne; Lindström, Outi; Grönroos, Juha; Saarela, Arto; Mustonen, Harri; Halttunen, Jorma

    2015-07-01

    The use of covered self-expandable metallic stents (cSEMS) in benign biliary indications is evolving. The aim of the study was to assess the safety and feasibility of cSEMS compared with multiple plastic stents in the treatment of benign biliary stricture (BBS) caused by chronic pancreatitis. This was a prospective, multicenter, randomized study of 60 patients with BBS caused by chronic pancreatitis. All patients received an initial plastic stent before randomization. At randomization, the stent was replaced either with a single cSEMS or three plastic stents. After 3 months, the position of the cSEMS was checked or another three plastic stents were added. At 6 months after randomization, all stents were removed. Clinical follow-up including abdominal ultrasound and laboratory tests were performed at 6 months and 2 years after stent removal. Two patients dropped out of the cSEMS group before stent removal. In April 2014, the median follow-up was 40 months (range 1 - 66 months). The 2-year, stricture-free success rate was 90 % (95 % confidence interval [CI] 72 % - 97 %) in the plastic stent group and 92 % (95 %CI 70 % - 98 %) in the cSEMS group (P = 0.405). There was one late recurrence in the plastic stent group 50 months after stent removal. Stent migration occurred three times (10 %) in the plastic stent group and twice in the cSEMS group (7 %; P = 1.000). A 6-month treatment with either six 10-Fr plastic stents or with one 10-mm cSEMS produced good long-term relief of biliary stricture caused by chronic pancreatitis.Study registered at ClinicalTrials.gov (NCT01085747). © Georg Thieme Verlag KG Stuttgart · New York.

  10. Overview of Flexible Electronics Technology

    NASA Astrophysics Data System (ADS)

    Cheng, I.-Chun; Wagner, Sigurd

    This chapter provides an overview of the history, concepts, and possible applications of flexible electronics from the perspectives of materials and fabrication technology. The focus is on large-area capable electronic surfaces. These are made of backplane and frontplane optoelectronics that are fabricated as fully integrated circuits on flexible substrates. The discussion covers flexible electronics, and reaches back to rigid-substrate precursor technology where appropriate. Flexible electronics is a wide-open and rapidly developing field of research, development, pilot production, and field trials. The chapter puts a perspective on the technology by systematizing it and by describing representative examples.

  11. Sky cover

    NASA Astrophysics Data System (ADS)

    Gerth, Jordan J.

    Of all of the standard meteorological parameters collected and observed daily, sky cover is not only one of the most complex, but the one that is fairly ambiguously defined and difficult to quantify. Despite that, the implications of how cloud fraction and sky cover are understood not only impact daily weather forecasts, but also present challenges to assessing the state of the earth's climate system. Part of the reason for this is the lack of observational methods for verifying the skill of clouds represented and parameterized in numerical models. While human observers record sky cover as part of routine duties, the spatial coverage of such observations in the United States is relatively sparse. There is greater spatial coverage of automated observations, and essentially complete coverage from geostationary weather satellites that observe the Americas. A good analysis of sky cover reconciles differences between manual observations, automated observations, and satellite observations, through an algorithm that accounts for the strengths and weaknesses of each dataset. This work describes the decision structure for trusting and weighting these similar observations. Some of the issues addressed include: human and instrument error resulting from approximations and estimations, a deficiency in high cloud detectability using surface-based ceilometers, poorly resolved low cloud using infrared channels on space-based radiometers during overnight hours, and decreased confidence in satellite-detected cloud during stray light periods. Using the blended sky cover analysis as the best representation of cloudiness, it is possible to compare the analysis to numerical model fields in order to assess the performance of the model and the parameterizations therein, as well as confirm or uncover additional relationships between sky cover and pertinent fields using an optimization methodology. The optimizer minimizes an affine expression of adjusted fields to the "truth" sky cover

  12. Active damping in a flexible manipulator

    NASA Technical Reports Server (NTRS)

    Pham, Trung T.

    1990-01-01

    Viewgraphs on active damping in a flexible manipulator are presented. Topics covered include: Shuttle Remote Manipulator System (SRMS); flexible structures; vibration; modeling of a flexible manipulator dynamical structure; designing control law criterion that minimizes vibration; and candidate application of fuzzy logic control law to the problem.

  13. Flexibility Program

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    These brief guidelines for a muscular flexibility program state that the purpose of such a program is to increase the range of motion in order to avoid injuries and eliminate awkwardness in physical activities. A flexibility program is described as an extension of the warm-up period and should be an ongoing, permanent effort to lengthen muscles. A…

  14. Flexible Scheduling.

    ERIC Educational Resources Information Center

    Davis, Harold S.; Bechard, Joseph E.

    A flexible schedule allows teachers to change group size, group composition, and class length according to the purpose of the lesson. This pamphlet presents various "master" schedules for flexible scheduling: (1) Simple block schedules, (2) back-to-back schedules, (3) interdisciplinary schedules, (4) school-wide block schedules, (5) open-lab…

  15. Bone Marrow Nails Created by Percutaneous Osteoplasty for Long Bone Fracture: Comparisons Among Acrylic Cement Alone, Acrylic-Cement-Filled Bare Metallic Stent, and Acrylic-Cement-Filled Covered Metallic Stent

    SciTech Connect

    Nakata, Kouhei; Kawai, Nobuyuki; Sato, Morio Cao, Guang; Sahara, Shinya; Sonomura, Tetsuo; Takasaka, Isao; Minamiguchi, Hiroki; Nakai, Motoki

    2011-06-15

    Purpose: This study was designed to compare the strength among bone marrow nails created to treat long bone fractures using interventional procedures. Methods: Twelve resected intact tibiae of healthy swine were used. A circumferential bone fracture was made in nine tibiae and restored with the following created bone marrow nails: acrylic cement alone (ACA) (n = 3), acrylic-cement-filled bare metallic stent (AC-FBMS) (n = 3), and acrylic-cement-filled covered metallic (AC-FCMS) stent (n = 3). The remaining intact tibiae (n = 3) were used as controls. Results: A bone marrow nail was successfully achieved within 30 min in all swine. The maximum injection volume of acrylic cement for creating ACA, AC-FBMS, and AC-FCMS was 1.7 {+-} 0.3, 3.2 {+-} 0.4, and 2.9 {+-} 0.4 mL, respectively. The thickness of bone marrow nail created in the ACA, AC-FBMS, and AC-FCMS groups was 3.6 {+-} 1.0, 10.3 {+-} 0.26, and 9.6 {+-} 0.32 mm, respectively (AC-FBMS group versus AC-FCMS group, p = 0.038), probably because of leakage of acrylic cement surrounding the interstices. The maximum bending power (kilonewton) and bending strength (newton/mm{sup 2}) in the normal long bone, ACA, AC-FBMS, and AC-FCMS groups were: 1.70 {+-} 0.25 and 79.2 {+-} 16.1; 0.21 {+-} 0.11 and 8.8 {+-} 2.8; 0.46 {+-} 0.06 and 18.2 {+-} 1.6; and 0.18 {+-} 0.04 and 7.8 {+-} 2.7, respectively. Conclusions: Although the maximum bending power and bending strength of AC-FBMS were not satisfactory, it was the most robust of the three marrow nails for restoring fractured long bone.

  16. Metal Oxide Nanostructures Generated from In Situ Sacrifice of Zinc in Bimetallic Textures as Flexible Ni/Fe Fast Battery Electrodes.

    PubMed

    Huang, Tianyi; Liu, Zhifang; Zhang, Zitong; Xiao, Bangqing; Jin, Yong

    2017-08-04

    An "in situ sacrifice" process was devised in this work as a room-temperature, all-solution processed electrochemical method to synthesize nanostructured NiOx and FeOx directly on current collectors. After electrodepositing NiZn/FeZn bimetallic textures on a copper net, the zinc component is etched and the remnant nickel/iron are evolved into NiOx and FeOx by the "in situ sacrifice" activation we propose. As-prepared electrodes exhibit high areal capacities of 0.47 mA h cm(-2) and 0.32 mA h cm(-2) , respectively. By integrating NiOx as the cathode, FeOx as the anode, and poly(vinyl alcohol) (PVA)-KOH gel as the separator/solid-state electrolyte, the assembled quasi-solid-state flexible battery delivers a volumetric capacity of 6.91 mA h cm(-3) at 5 mA cm(-2) , along with a maximum energy density of 7.40 mWh cm(-3) under a power density of 0.27 W cm(-3) and a maximum tested power density of 3.13 W cm(-3) with a 2.17 mW h cm(-3) energy density retention. Our room-temperature synthesis, which only consumes minute electricity, makes it a promising approach for large-scale production. We also emphasize the in situ sacrifice zinc etching process used in this work as a general strategy for metal-based nanostructure growth for high-performance battery materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Adsorption of N/S heterocycles in the flexible metal-organic framework MIL-53(Fe(III)) studied by in situ energy dispersive X-ray diffraction.

    PubMed

    Van de Voorde, Ben; Munn, Alexis S; Guillou, Nathalie; Millange, Franck; De Vos, Dirk E; Walton, Richard I

    2013-06-14

    The adsorption of N/S-containing heterocyclic organic molecules in the flexible iron(III) terephthalate MIL-53, Fe(III)(OH)(0.6)F(0.4)(O2C-C6H4-CO2)·(H2O), from the liquid phase was studied with in situ energy dispersive X-ray diffraction (EDXRD), in order to follow the adsorption-induced expansion of the structure. For comparison with the diffraction data, liquid phase adsorption isotherms were recorded for uptake of benzothiophene, benzothiazole and indole in isopropanol and in heptane. The solvent not only influences pore opening but is also a competing guest. The in situ EDXRD experiments allow the kinetics of guest uptake and the competition with solvent to be monitored directly. Indole uptake is limited; this adsorbate is barely capable of opening the closed, either hydrated or dehydrated, MIL-53(Fe) structure, or of penetrating the isopropanol-containing material in the concentration range under study. When isopropanol is used as a solvent, the guest molecules benzothiophene and benzothiazole must be present at a certain threshold concentration before substantial adsorption into the metal-organic framework takes place, eventually resulting in full opening of the structure. The fully expanded structures of benzothiophene or benzothiazole loaded MIL-53(Fe) materials have Imcm symmetry and a unit cell volume of ca. 1600 Å(3), and upon uptake of the guest molecules by the closed form (unit cell volume ~1000 Å(3)) no intermediate crystalline phases are seen. Successful uptake by MIL-53(Fe) requires that the adsorbate is primarily a good hydrogen bond acceptor; additionally, based on UV-visible spectroscopy, a charge-transfer interaction between the S atoms of benzothiophene and the aromatic rings in the MOF pore wall is proposed.

  18. Cover Crops

    USDA-ARS?s Scientific Manuscript database

    Cover crops are great tools to improve soil quality and health, and great tools to increase carbon sequestration. They are nutrient management tools that can help scavenge nitrate, cycle nitrogen to the following crop, mine NO3 from groundwater, and increase nitrogen use efficiency of cropping syste...

  19. Correction: Prospective pilot study of fully covered self-expandable metal stents for refractory benign pancreatic duct strictures: long-term outcomes

    PubMed Central

    Matsubara, Saburo; Sasahira, Naoki; Isayama, Hiroyuki; Takahara, Naminatsu; Mizuno, Suguru; Kogure, Hirofumi; Yamamoto, Natsuyo; Nakai, Yousuke; Tada, Minoru; Koike, Kazuhiko

    2016-01-01

    Background and study aims: Background and study aims: Temporary placement of a fully covered self-expandable metal stent (FCSEMS) has recently emerged as a treatment option for pancreatic duct strictures due to chronic pancreatitis refractory to conventional plastic stenting. However, there are no data about long-term outcomes with this therapeutic option. The aims of the current study were to estimate the feasibility, safety, efficacy, and long-term outcomes of temporary FCSEMS placement for refractory pancreatic duct strictures. Patients and methods: This was a prospective, single-center feasibility study. Ten patients with refractory pancreatic duct strictures due to chronic pancreatitis underwent FCSEMS placement for 3 months. We evaluated the rate of recurrent symptoms after stent removal during long-term follow-up, as well as adverse events (AEs). Results: Two patients required early (within 1 week) stent removal because of intolerable pain or pancreatitis. In the remaining 8 patients, the recurrence rate of any symptoms after FCSEMS removal was 63% during 35 months of follow up. The causes of recurrent symptoms were as follows: recurrence of stricture in 2; stent-induced stricture in 1; impaction of pancreatic stones in 1; and development of a pseudocyst in 1. When limited to stricture, the recurrence rate was 38%. Additional endoscopic treatments were required in 4 patients: a second FCSEMS placement in 1; plastic stent (PS) placement in 1; stone extraction in 1; and endoscopic ultrasound–guided pseudocyst drainage in 1. Asymptomatic stent migration occurred in 2 patients. Suppurative pancreatic ductitis due to food impaction in the FCSEMS occurred in 2 patients, and endoscopic pancreatic duct drainage was performed. Stent-induced ductal changes developed in 2 patients and PS treatment was required in 1 patient for pain relief. Conclusion: The FCSEMS appears to be a feasible and potentially effective option for the management of refractory pancreatic duct

  20. COVERING A CORE BY EXTRUSION

    DOEpatents

    Karnie, A.J.

    1963-07-16

    A method of covering a cylindrical fuel core with a cladding metal ms described. The metal is forced between dies around the core from both ends in two opposing skirts, and as these meet the ends turn outward into an annular recess in the dics. By cutting off the raised portion formed by the recess, oxide impurities are eliminated. (AEC)

  1. Flexible Sigmoidoscopy

    MedlinePlus

    ... Task Force (USPSTF). Most doctors recommend colonoscopy to screen for colon cancer because colonoscopy shows the entire colon and can remove colon polyps. However, preparing for and performing a flexible sigmoidoscopy may take less time and you may ...

  2. Flexible Straws.

    ERIC Educational Resources Information Center

    Prentice, Gerard

    1989-01-01

    Discusses the use of flexible straws for teaching properties of figures and families of shapes. Describes a way to make various two- or three-dimensional geometric shapes. Lists eight advantages of the method. (YP)

  3. Flexible Parsing.

    DTIC Science & Technology

    1982-10-22

    grammaticality. The primary objective of this project Is to develop flexible computer q parsing techniques which can deal with the various kinds of...0143 6. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT . TASK Computer Science Department Carnegie-Nellon University PE61102F; 2304...spontaneously, the, often do not adhere strictly to commonly accepted standards of grammaticalitf. The primary objective of this proJect is to develop flexible

  4. Composite Flexible Blanket Insulation

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A. (Inventor); Pitts, William C. (Inventor); Goldstein, Howard E. (Inventor); Sawko, Paul M. (Inventor)

    1991-01-01

    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  5. Industrial Fuel Flexibility Workshop

    SciTech Connect

    none,

    2006-09-01

    On September 28, 2006, in Washington, DC, ITP and Booz Allen Hamilton conducted a fuel flexibility workshop with attendance from various stakeholder groups. Workshop participants included representatives from the petrochemical, refining, food and beverage, steel and metals, pulp and paper, cement and glass manufacturing industries; as well as representatives from industrial boiler manufacturers, technology providers, energy and waste service providers, the federal government and national laboratories, and developers and financiers.

  6. An ordered bcc CuPd nanoalloy synthesised via the thermal decomposition of Pd nanoparticles covered with a metal-organic framework under hydrogen gas.

    PubMed

    Li, Guangqin; Kobayashi, Hirokazu; Kusada, Kohei; Taylor, Jared M; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Matsumura, Syo; Kitagawa, Hiroshi

    2014-11-18

    Presented here is the synthesis of an ordered bcc copper-palladium nanoalloy, via the decomposition of a Pd nanoparticle@metal-organic framework composite material. In situ XRD measurements were performed in order to understand the mechanism of the decomposition process. This result gives a further perspective into the synthesis of new nanomaterials via metal-organic framework decomposition.

  7. [Snow cover pollution monitoring in Ufa].

    PubMed

    Daukaev, R A; Suleĭmanov, R A

    2008-01-01

    The paper presents the results of examining the snow cover polluted with heavy metals in the large industrial town of Ufa. The level of man-caused burden on the snow cover of the conventional parts of the town was estimated and compared upon exposure to a wide range of snow cover pollutants. The priority snow cover pollutants were identified among the test heavy metals.

  8. Inkjet-printed flexible organic thin-film thermoelectric devices based on p- and n-type poly(metal 1,1,2,2-ethenetetrathiolate)s/polymer composites through ball-milling

    PubMed Central

    Jiao, Fei; Di, Chong-an; Sun, Yimeng; Sheng, Peng; Xu, Wei; Zhu, Daoben

    2014-01-01

    In this article, we put forward a simple method for the synthesis of thermoelectric (TE) composite materials. Both n- and p-type composites were obtained by ball-milling the insoluble and infusible metal coordination polymers with other polymer solutions. The particle size, film morphology and composition were characterized by dynamic light scattering, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The TE properties of the drop-cast composite film were measured at different temperatures. An inkjet-printed flexible device was fabricated and the output voltage and short-circuit current at various hot-side temperatures (Thot) and temperature gradients (ΔT) were tested. The composite material not only highly maintained the TE properties of the pristine material but also greatly improved its processability. This method can be extended to other insoluble and infusible TE materials for solution-processed flexible TE devices. PMID:24615147

  9. Flexible flatfoot

    PubMed Central

    Atik, Aziz; Ozyurek, Selahattin

    2014-01-01

    While being one of the most frequent parental complained deformities, flatfoot does not have a universally accepted description. The reasons of flexible flatfoot are still on debate, but they must be differentiated from rigid flatfoot which occurs secondary to other pathologies. These children are commonly brought up to a physician without any complaint. It should be kept in mind that the etiology may vary from general soft tissue laxities to intrinsic foot pathologies. Every flexible flatfoot does not require radiological examination or treatment if there is no complaint. Otherwise further investigation and conservative or surgical treatment may necessitate. PMID:28058304

  10. Piping Flexibility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  11. Zipper Connectors for Flexible Electronic Circuits

    NASA Technical Reports Server (NTRS)

    Barnes, Kevin N.

    2003-01-01

    Devices that look and function much like conventional zippers on clothing have been proposed as connectors for flexible electronic circuits. Heretofore, flexible electronic circuits have commonly included rigid connectors like those of conventional rigid electronic circuits. The proposed zipper connectors would make it possible to connect and disconnect flexible circuits quickly and easily. Moreover, the flexibility of zipper connectors would make them more (relative to rigid connectors) compatible with flexible circuits, so that the advantages of flexible circuitry could be realized more fully. Like a conventional zipper, a zipper according to the proposal would include teeth anchored on flexible tapes, a slider with a loosely attached clasp, a box at one end of the rows of mating teeth, and stops at the opposite ends. The tapes would be made of a plastic or other dielectric material. On each of the two mating sides of the zipper, metal teeth would alternate with dielectric (plastic) teeth, there being two metal teeth for each plastic one. When the zipper was closed, each metal tooth from one side would be in mechanical and electrical contact with a designated metal tooth from the other side, and these mating metal teeth would be electrically insulated from the next pair of mating metal teeth by an intervening plastic tooth. The metal teeth would be soldered or crimped to copper tabs. Wires or other conductors connected to electronic circuits would be soldered or crimped to the ends of the tabs opposite the teeth.

  12. Use of a novel covered self-expandable metal stent with an anti-migration system for endoscopic ultrasound-guided drainage of a pseudocyst

    PubMed Central

    Téllez-Ávila, Félix Ignacio; Villalobos-Garita, Álvaro; Ramírez-Luna, Miguel Ángel

    2013-01-01

    The development of pseudocysts in patients with chronic pancreatitis has been reported in 23%-60% of cases and drainage is indicated when they become symptomatic. Endoscopic ultrasound-guided drainage with the placement of plastic or metallic stents to create a cystogastric anastomosis has been shown to be a reliable and efficacious maneuver. Metallic stent use appears to be a safe and effective alternative that shortens the length of time of the procedure and maintains a greater diameter in the cystogastric communication. However, important migration rates have been reported. The use of new metallic stents that are specially designed to prevent migration represents a promising development in the treatment of these group of patients that appears to be safe and effective for pseudocyst drainage and could importantly reduce migration rates, while at the same time having the advantage of a single step procedure and a larger fistula diameter in the endoscopic cystogastric anastomosis. PMID:23772268

  13. Two-dimensional molybdenum disulphide nanosheet-covered metal nanoparticle array as a floating gate in multi-functional flash memories

    NASA Astrophysics Data System (ADS)

    Han, Su-Ting; Zhou, Ye; Chen, Bo; Zhou, Li; Yan, Yan; Zhang, Hua; Roy, V. A. L.

    2015-10-01

    Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal NPs-MoS2 floating gate flash memories were further proven to be multi-bit memory storage devices possessing a 3-bit storage capability and a good retention capability up to 104 s. We anticipate that these findings would provide scientific insight for the development of novel memory devices utilizing an atomically thin two-dimensional lattice structure.Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal

  14. Land cover

    USGS Publications Warehouse

    Jorgenson, Janet C.; Joria, Peter C.; Douglas, David C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Documenting the distribution of land-cover types on the Arctic National Wildlife Refuge coastal plain is the foundation for impact assessment and mitigation of potential oil exploration and development. Vegetation maps facilitate wildlife studies by allowing biologists to quantify the availability of important wildlife habitats, investigate the relationships between animal locations and the distribution or juxtaposition of habitat types, and assess or extrapolate habitat characteristics across regional areas.To meet the needs of refuge managers and biologists, satellite imagery was chosen as the most cost-effective method for mapping the large, remote landscape of the 1002 Area.Objectives of our study were the following: 1) evaluate a vegetation classification scheme for use in mapping. 2) determine optimal methods for producing a satellite-based vegetation map that adequately met the needs of the wildlife research and management objectives; 3) produce a digital vegetation map for the Arctic Refuge coastal plain using Lands at-Thematic Mapper(TM) satellite imagery, existing geobotanical classifications, ground data, and aerial photographs, and 4) perform an accuracy assessment of the map.

  15. Single-crystal-like, c-axis oriented BaTiO3 thin films with high-performance on flexible metal templates for ferroelectric applications

    NASA Astrophysics Data System (ADS)

    Shin, Junsoo; Goyal, Amit; Jesse, Stephen; Kim, Dae Ho

    2009-06-01

    Epitaxial, c-axis oriented BaTiO3 thin films were deposited using pulsed laser ablation on flexible, polycrystalline Ni alloy tape with biaxially textured oxide buffer multilayers. The high quality of epitaxial BaTiO3 thin films with P4mm group symmetry was confirmed by x-ray diffraction. The microscopic ferroelectric domain structure and the piezoelectric domain switching in these films were confirmed via spatially resolved piezoresponse mapping and local hysteresis loops. Macroscopic measurements demonstrate that the films have well-saturated hysteresis loops with a high remanent polarization of ˜11.5 μC/cm2. Such high-quality, single-crystal-like BaTiO3 films on low-cost, polycrystalline, flexible Ni alloy substrates are attractive for applications in flexible lead-free ferroelectric devices.

  16. 29 CFR 1915.54 - Welding, cutting and heating of hollow metal containers and structures not covered by § 1915.12.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Welding, cutting and heating of hollow metal containers and... STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.54 Welding, cutting and heating of... which have contained flammable substances shall, before welding, cutting, or heating is undertaken...

  17. 29 CFR 1915.54 - Welding, cutting and heating of hollow metal containers and structures not covered by § 1915.12.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Welding, cutting and heating of hollow metal containers and... STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.54 Welding, cutting and heating of... which have contained flammable substances shall, before welding, cutting, or heating is undertaken...

  18. 29 CFR 1915.54 - Welding, cutting and heating of hollow metal containers and structures not covered by § 1915.12.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Welding, cutting and heating of hollow metal containers and... STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.54 Welding, cutting and heating of... which have contained flammable substances shall, before welding, cutting, or heating is undertaken...

  19. Characterisation and treatment of roads covered with zinc ashes, muffle furnace fragments and lead slags from former non-ferrous metal industries in Belgium.

    PubMed

    Vandecasteele, C; Van den Broeck, K; Van Gerven, T; Dutré, V; Seuntjens, P; Berghmans, P; Cornelis, C; Nouwen, J

    2002-08-01

    Zinc ashes, muffle furnace fragments and lead slags from non-ferrous industries were applied to pave roads in the North of Belgium. From an inventory it appeared that there are at least 490 km of such roads. In our survey the materials on these roads were characterised. The total metal concentration, the availability and the leaching as a function of time were determined. It appeared that these materials contain high concentrations of heavy metals, some of which are readily available. The high leaching of some metals makes them as such unsuitable as secondary construction material. Methods for the application of these materials for road construction were examined where the materials replaced part of the sand and gravel fraction in lean concrete and in bituminous mixtures, or where they replaced the sand in sand-cement mixtures, all these to be used for road foundations, cycle tracks, etc. When lead slags were applied in lean concrete, a material was obtained complying with the standards for secondary construction materials and with sufficient compressive strength for road foundations. When zinc ashes or muffle fragments were used to replace sand in sand-cement mixtures, again a suitable construction material was obtained. The other combinations tried out were rather unsuccessful, because of high metal leaching and/or poor compressive strength.

  20. 29 CFR 1915.54 - Welding, cutting and heating of hollow metal containers and structures not covered by § 1915.12.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Welding, cutting and heating of hollow metal containers and... STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.54 Welding, cutting and heating of... which have contained flammable substances shall, before welding, cutting, or heating is undertaken...

  1. 29 CFR 1915.54 - Welding, cutting and heating of hollow metal containers and structures not covered by § 1915.12.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Welding, cutting and heating of hollow metal containers and... STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.54 Welding, cutting and heating of... which have contained flammable substances shall, before welding, cutting, or heating is undertaken...

  2. Covered self-expandable metal stents with an anti-migration system improve patency duration without increased complications compared with uncovered stents for distal biliary obstruction caused by pancreatic carcinoma: a randomized multicenter trial.

    PubMed

    Kitano, Masayuki; Yamashita, Yukitaka; Tanaka, Kiyohito; Konishi, Hideyuki; Yazumi, Shujiro; Nakai, Yoshitaka; Nishiyama, Osamu; Uehara, Hiroyuki; Mitoro, Akira; Sanuki, Tsuyoshi; Takaoka, Makoto; Koshitani, Tatsuya; Arisaka, Yoshifumi; Shiba, Masatsugu; Hoki, Noriyuki; Sato, Hideki; Sasaki, Yuichi; Sato, Masako; Hasegawa, Kazunori; Kawabata, Hideaki; Okabe, Yoshihiro; Mukai, Hidekazu

    2013-11-01

    The requirements of biliary stents used in the palliation of malignant biliary obstruction are a long duration of patency and minimal adverse effects. Covered self-expandable metal stents (SEMSs) have been shown to prevent tumor ingrowth, which is the most frequent complication of uncovered SEMSs. However, because they are prone to migration, the superiority of covered SEMS has yet to be convincingly demonstrated. The aim of this study was to evaluate the superiority of covered over uncovered SEMSs in the palliation of distal biliary obstruction due to unresectable pancreatic carcinoma, using both stent types with relatively low axial force and uncovered flared ends to prevent their migration. From April 2009 to December 2010, 120 patients who were admitted to 22 tertiary-care centers because of distal biliary obstruction from unresectable pancreatic carcinomas were enrolled in this prospective randomized multicenter study. Patients were randomly assigned to receive a covered or uncovered SEMS deployed at the site of the biliary stricture during endoscopic retrograde cholangiopancreatography. Stent patency time, patient survival time, patient survival time without stent dysfunction (time to stent dysfunction or patient death), cause of stent dysfunction (ingrowth, overgrowth, migration, or sludge formation), and serious adverse events were compared between covered and uncovered SEMS groups. Patient survival time in the two groups did not significantly differ (median: 285 and 223 days, respectively; P=0.68). Patient survival time without stent dysfunction was significantly longer in the covered than in the uncovered SEMS group (median: 187 vs. 132 days; P=0.043). Stent patency was also significantly longer in the covered than in the uncovered SEMS group (mean±s.d.: 219.3±159.1 vs. 166.9±124.9 days; P=0.047). Reintervention for stent dysfunction was performed in 14 of 60 patients with covered SEMSs (23%) and in 22 of 60 patients with uncovered SEMSs (37%; P=0

  3. Flexible Photovoltaics: Mission Power from the Sun

    DTIC Science & Technology

    2009-11-01

    UNCLASSIFIED Flexible Photovoltaics : Mission Power from the Sun NSRDEC Project Officer: Steven Tucker Senior Engineer, EE COMM 508-233-6962 DSN 256...NOV 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Flexible Photovoltaics : Mission Power from the Sun...Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 UNCLASSIFIED Flexible Photovoltaics – Why? Travel Lighter, Stay Longer! Known

  4. Plastic tubing protects flexible copper hose

    NASA Technical Reports Server (NTRS)

    Mellgren, B. E.

    1966-01-01

    Flexible copper purge and coolant hoses is covered with a high-temperature shrinkable plastic for protection against severe vibration during rocket engine tests. This type of tubing is being used on all flexible water tubes used in F-1 engine tests.

  5. 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.

  6. Valuing Flexibility

    DTIC Science & Technology

    2010-11-09

    Bunker   Buster ”  of  Desert  Storm  (evolved  into  GBU...modular   muni=ons  to  achieve   opera=onal  flexibility   •  Various  configura=ons  are   allowable  based  on   warhead ...28)   –  New   warhead  “module”  used  in  conjunc=on  with  exis=ng  guidance  and  fuze   modules   – 

  7. X-ray diffraction and high-resolution TEM observations of biopolymer nanoskin-covered metallic copper fine particles: preparative conditions and surface oxidation states.

    PubMed

    Yonezawa, Tetsu; Uchida, Yoshiki; Tsukamoto, Hiroki

    2015-12-28

    Metallic copper fine particles used for electro conductive pastes were prepared by the chemical reduction of cupric oxide microparticles in the presence of gelatin. After reduction, the fine particles were collected by decantation with pH control and washing, followed by drying at a moderate temperature. The surface oxidation state of the obtained copper fine particles could be considerably varied by altering the pH of the particle dispersion, as shown by X-ray diffraction and high-resolution transmission electron microscopy. Our results strongly indicate that decantation under a nitrogen atmosphere can prevent the oxidation of copper fine particles but a slight oxidation was found.

  8. Flexible Sandwich Diaphragms Are Less Permeable

    NASA Technical Reports Server (NTRS)

    Michalovic, John G.; Vassallo, Franklin A.

    1993-01-01

    Diaphragms for use in refrigerator compressors made as laminates of commercially available elastomers and metals. Diaphragms flexible, but less permeable by chlorofluorocarbon refrigerant fluids than diaphragms made of homogeneous mixtures of materials.

  9. High-performance flexible electrochromic device based on facile semiconductor-to-metal transition realized by WO3·2H2O ultrathin nanosheets

    PubMed Central

    Liang, Lin; Zhang, Jiajia; Zhou, Yingying; Xie, Junfeng; Zhang, Xiaodong; Guan, Meili; Pan, Bicai; Xie, Yi

    2013-01-01

    Ultrathin nanosheets are considered as one kind of the most promising candidates for the fabrication of flexible electrochromic devices (ECDs) due to their permeable channels, high specific surface areas, and good contact with the substrate. Herein, we first report the synthesis of large-area nanosheets of tungsten oxide dihydrate (WO3·2H2O) with a thickness of only about 1.4 nm, showing much higher Li+ diffusion coefficients than those of the bulk counterpart. The WO3·2H2O ultrathin nanosheets are successfully assembled into the electrode of flexible electrochromic device, which exhibits wide optical modulation, fast color-switching speed, high coloration efficiency, good cyclic stability and excellent flexibility. Moreover, the electrochromic mechanism of WO3·2H2O is further investigated by first-principle density functional theory (DFT) calculations, in which the relationship between structural features of ultrathin nanosheets and coloration/bleaching response speed is revealed. PMID:23728489

  10. Flexible retinal electrode array

    DOEpatents

    Okandan, Murat; Wessendorf, Kurt O.; Christenson, Todd R.

    2006-10-24

    An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

  11. Tests on Double Layer Metalization

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1983-01-01

    28 page report describes experiments in fabrication of integrated circuits with double-layer metalization. Double-layer metalization requires much less silicon "real estate" and allows more flexibility in placement of circuit elements than does single-layer metalization.

  12. Asymmetric Flexible Supercapacitor Stack

    NASA Astrophysics Data System (ADS)

    Leela Mohana Reddy, A.; Estaline Amitha, F.; Jafri, Imran; Ramaprabhu, S.

    2008-04-01

    Electrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs) have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm) based AB3 alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM and HRTEM). An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion® membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  13. Salt Filler For Making Covered Channels

    NASA Technical Reports Server (NTRS)

    Mckechnie, Timothy N.; Holmes, Richard R.

    1991-01-01

    In simple fabrication technique, metal salts used to create such subsurface channels as those for coolant in metallic heat exchanger. Layer of metal deposited on structure by vacuum plasma spraying, sealing channels. Metal salt or salt mixture has melting temperature higher than those of waxes and aluminum and withstands high temperature of plasma spraying. After plasma spraying, salt filler dissolved quickly and easily and flushed away with water or other appropriate solvent, leaving behind covered channels.

  14. Optimizing ultrathin Ag films for high performance oxide-metal-oxide flexible transparent electrodes through surface energy modulation and template-stripping procedures

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Gao, Pingqi; Yang, Zhenhai; Zhu, Juye; Huang, Feng; Ye, Jichun

    2017-03-01

    Among new flexible transparent conductive electrode (TCE) candidates, ultrathin Ag film (UTAF) is attractive for its extremely low resistance and relatively high transparency. However, the performances of UTAF based TCEs critically depend on the threshold thickness for growth of continuous Ag films and the film morphologies. Here, we demonstrate that these two parameters could be strongly altered through the modulation of substrate surface energy. By minimizing the surface energy difference between the Ag film and substrate, a 9 nm UTAF with a sheet resistance down to 6.9 Ω sq‑1 can be obtained using an electron-beam evaporation process. The resultant UTAF is completely continuous and exhibits smoother morphologies and smaller optical absorbances in comparison to the counterpart of granular-type Ag film at the same thickness without surface modulation. Template-stripping procedure is further developed to transfer the UTAFs to flexible polymer matrixes and construct Al2O3/Ag/MoOx (AAM) electrodes with excellent surface morphology as well as optical and electronic characteristics, including a root-mean-square roughness below 0.21 nm, a transparency up to 93.85% at 550 nm and a sheet resistance as low as 7.39 Ω sq‑1. These AAM based electrodes also show superiority in mechanical robustness, thermal oxidation stability and shape memory property.

  15. Optimizing ultrathin Ag films for high performance oxide-metal-oxide flexible transparent electrodes through surface energy modulation and template-stripping procedures.

    PubMed

    Yang, Xi; Gao, Pingqi; Yang, Zhenhai; Zhu, Juye; Huang, Feng; Ye, Jichun

    2017-03-14

    Among new flexible transparent conductive electrode (TCE) candidates, ultrathin Ag film (UTAF) is attractive for its extremely low resistance and relatively high transparency. However, the performances of UTAF based TCEs critically depend on the threshold thickness for growth of continuous Ag films and the film morphologies. Here, we demonstrate that these two parameters could be strongly altered through the modulation of substrate surface energy. By minimizing the surface energy difference between the Ag film and substrate, a 9 nm UTAF with a sheet resistance down to 6.9 Ω sq(-1) can be obtained using an electron-beam evaporation process. The resultant UTAF is completely continuous and exhibits smoother morphologies and smaller optical absorbances in comparison to the counterpart of granular-type Ag film at the same thickness without surface modulation. Template-stripping procedure is further developed to transfer the UTAFs to flexible polymer matrixes and construct Al2O3/Ag/MoOx (AAM) electrodes with excellent surface morphology as well as optical and electronic characteristics, including a root-mean-square roughness below 0.21 nm, a transparency up to 93.85% at 550 nm and a sheet resistance as low as 7.39 Ω sq(-1). These AAM based electrodes also show superiority in mechanical robustness, thermal oxidation stability and shape memory property.

  16. Optimizing ultrathin Ag films for high performance oxide-metal-oxide flexible transparent electrodes through surface energy modulation and template-stripping procedures

    PubMed Central

    Yang, Xi; Gao, Pingqi; Yang, Zhenhai; Zhu, Juye; Huang, Feng; Ye, Jichun

    2017-01-01

    Among new flexible transparent conductive electrode (TCE) candidates, ultrathin Ag film (UTAF) is attractive for its extremely low resistance and relatively high transparency. However, the performances of UTAF based TCEs critically depend on the threshold thickness for growth of continuous Ag films and the film morphologies. Here, we demonstrate that these two parameters could be strongly altered through the modulation of substrate surface energy. By minimizing the surface energy difference between the Ag film and substrate, a 9 nm UTAF with a sheet resistance down to 6.9 Ω sq−1 can be obtained using an electron-beam evaporation process. The resultant UTAF is completely continuous and exhibits smoother morphologies and smaller optical absorbances in comparison to the counterpart of granular-type Ag film at the same thickness without surface modulation. Template-stripping procedure is further developed to transfer the UTAFs to flexible polymer matrixes and construct Al2O3/Ag/MoOx (AAM) electrodes with excellent surface morphology as well as optical and electronic characteristics, including a root-mean-square roughness below 0.21 nm, a transparency up to 93.85% at 550 nm and a sheet resistance as low as 7.39 Ω sq−1. These AAM based electrodes also show superiority in mechanical robustness, thermal oxidation stability and shape memory property. PMID:28291229

  17. Construction of helical coordination polymers via flexible conformers of bis(3-pyridyl)cyclotetramethylenesilane: metal(ii) and halogen effects on luminescence, thermolysis and catalysis.

    PubMed

    Kim, Hyeun; Park, Minwoo; Lee, Haeri; Jung, Ok-Sang

    2015-05-07

    Infinite rectangular-tubular helices, [MX2L] (M = Zn(ii), Hg(ii); X(-) = Cl(-), Br(-); L = bis(3-pyridyl)cyclotetramethylenesilane), have been efficiently constructed via the combined effects of the potential flexible conformers of L and the tetrahedral geometry of M(ii) ions. This helical molecular system affords a racemic mixture of P- and M-helices in a crystal. The helical pitches (7.8934(4)-8.1560(2) Å) that are sensitive to the nature of M(ii) ions and halide anions are attributable to subtle change in the flexible dihedral angles between the two pyridyl groups around Si and the M(ii) hinges. Their photoluminescence intensities, correspondingly, are in the order [ZnCl2L] > [ZnBr2L] ≫ [HgCl2L] > [HgBr2L]. Zinc(ii) complexes show recyclable catalytic effects on the transesterification reaction in the order [ZnCl2L] > [ZnBr2L]. Calcination of [ZnCl2L] and [ZnBr2L] at 500 °C produces uniform hexagonal tubular spire crystals of 1.2 × 1.2 × 4.0 μm(3) dimensions and spheres, respectively.

  18. Malignant tracheal-mediastinal-parenchymal-pleural fistula after chemoradiation plus bevacizumab: management with a Y-silicone stent inside a metallic covered stent.

    PubMed

    Machuzak, Michael S; Santacruz, Jose F; Jaber, Wissam; Gildea, Thomas R

    2015-01-01

    Tracheal or bronchial-mediastinal fistulas are a rare entity associated to high mortality. We report a case of a 58-year-old man with an unresectable non-small cell carcinoma of the lung, treated with chemoradiation followed by bevacizumab. Approximately, 6 weeks after starting bevacizumab he developed a severe cough with copious secretions He could not lie supine due to the feeling of drowning. Investigations revealed a large tracheo-mediastinal-parenchymal-pleural fistula. Palliative management was offered with interventional bronchoscopic techniques. He was found to have a large central airway defect that obliterated almost 40% of the trachea. Under general anesthesia and positive pressure ventilation, a unique approach was used to rebuild an eroded tracheal and right main stem bronchial wall. A self-expanding metallic stent (SEMS) was placed to provide a scaffold of support, whereas a Dumon Y-stent was placed inside the SEMS. This combination allowed for a patent, stable airway; recreating the normal anatomy in a minimally invasive manner walling off the fistula. The patient was discharged 2 days after the bronchoscopic intervention, with significant palliation of his symptomatology. Eighteen months later, the upper lobe cavity persists with a stable airway and stents perfectly positioned with clinically insignificant evidence of stent related granulation in the upper trachea.

  19. DNA Flexibility

    NASA Astrophysics Data System (ADS)

    Widom, Jonathan

    2005-03-01

    Classic experimental and theoretical analyses led to a unified view of DNA as a semiflexible polymer, characterized by a bending persistence length, P, ˜50 nm (˜150 bp). In this view, DNA lengths that are greater than P are, on average, spontaneously gently bent, and require relatively little force to bend significantly, while DNA lengths that are shorter than P are nearly straight, and require great force to bend significantly. Nevertheless, sharply bent DNA plays important roles in biology. We used the method of ligase catalyzed DNA cyclization to investigate the spontaneous looping of short DNAs. Remarkably, DNAs as short as 84 bp spontaneously bend into circles, and 94 bp DNA sequences cyclize up to 10^5 times more easily than predicted from classic theories of DNA bending. In subsequent studies we find that the twistability of sharply looped DNAs exceeds the prediction of classic theories by up to 400-fold. These results can only be understood by greatly enhanced DNA flexibility, not by permanent bends. Our results provide striking support for two new theories of DNA mechanics based on local melted or kinked regions, and they establish DNA as an active participant in the formation and function of looped regulatory complexes in vivo.

  20. Modular synthesis of polyene side chain analogues of the potent macrolide antibiotic etnangien by a flexible coupling strategy based on hetero-bis-metallated alkenes.

    PubMed

    Altendorfer, Mario; Raja, Aruna; Sasse, Florenz; Irschik, Herbert; Menche, Dirk

    2013-04-07

    An efficient procedure for the concise synthesis of hetero-bis-metallated alkenes as useful building blocks for the modular access to highly elaborate polyenes and stabilized analogues is reported. By applying these bifunctional olefins in convergent Stille/Suzuki-Miyaura couplings, novel, carefully selected side chain analogues of the potent RNA polymerase inhibitor etnangien were synthesized by a modular late stage coupling strategy and evaluated for antibacterial and antiproliferative activities.

  1. CO2 Laser Direct Written MOF-Based Metal-Decorated and Heteroatom-Doped Porous Graphene for Flexible All-Solid-State Microsupercapacitor with Extremely High Cycling Stability.

    PubMed

    Basu, Aniruddha; Roy, Kingshuk; Sharma, Neha; Nandi, Shyamapada; Vaidhyanathan, Ramanathan; Rane, Sunit; Rode, Chandrashekhar; Ogale, Satishchandra

    2016-11-23

    Over the past decade, flexible and wearable microelectronic devices and systems have gained significant importance. Because portable power source is an essential need of such wearable devices, currently there is considerable research emphasis on the development of planar interdigitated micro energy -torage devices by employing diverse precursor materials to obtain functional materials (functional carbon, oxides, etc.) with the desirable set of properties. Herein we report for the first time the use of metal organic framework (MOF) and zeolitic imidazolate framework (ZIF-67) for high-wavelength photothermal laser direct writing of metal-decorated, heteroatom-doped, porous few-layer graphene electrodes for microsupercapacitor application. We argue that the specific attributes of MOF as a precursor and the high-wavelength laser writing approach (which creates extremely high localized and transient temperature (>2500 °C) due to strong absorption by lattice vibrations) are together responsible for the peculiar interesting properties of the carbon material thus synthesized, thereby rendering extremely high cycling stability to the corresponding microsupercapacitor device. Our device exhibits near 100% retention after 200 000 cycles as well as stability under 150° bending.

  2. High Performance Flexible Thermal Link

    NASA Astrophysics Data System (ADS)

    Sauer, Arne; Preller, Fabian

    2014-06-01

    The paper deals with the design and performance verification of a high performance and flexible carbon fibre thermal link.Project goal was to design a space qualified thermal link combining low mass, flexibility and high thermal conductivity with new approaches regarding selected materials and processes. The idea was to combine the advantages of existing metallic links regarding flexibility and the thermal performance of high conductive carbon pitch fibres. Special focus is laid on the thermal performance improvement of matrix systems by means of nano-scaled carbon materials in order to improve the thermal performance also perpendicular to the direction of the unidirectional fibres.One of the main challenges was to establish a manufacturing process which allows handling the stiff and brittle fibres, applying the matrix and performing the implementation into an interface component using unconventional process steps like thermal bonding of fibres after metallisation.This research was funded by the German Federal Ministry for Economic Affairs and Energy (BMWi).

  3. Turn-on luminescence sensing and real-time detection of traces of water in organic solvents by a flexible metal-organic framework.

    PubMed

    Douvali, Antigoni; Tsipis, Athanassios C; Eliseeva, Svetlana V; Petoud, Stéphane; Papaefstathiou, Giannis S; Malliakas, Christos D; Papadas, Ioannis; Armatas, Gerasimos S; Margiolaki, Irene; Kanatzidis, Mercouri G; Lazarides, Theodore; Manos, Manolis J

    2015-01-26

    The development of efficient sensors for the determination of the water content in organic solvents is highly desirable for a number of chemical industries. Presented herein is a Mg(2+) metal-organic framework (MOF), which exhibits the remarkable capability to rapidly detect traces of water (0.05-5 % v/v) in various organic solvents through an unusual turn-on luminescence sensing mechanism. The extraordinary sensitivity and fast response of this MOF for water, and its reusability make it one of the most powerful water sensors known.

  4. A Flexible Cloud Generator

    NASA Astrophysics Data System (ADS)

    Benassi, A.; Deguy, S.; Szczap, F.

    2001-05-01

    In this work we propose a flexible cloud generating model as well as a software. This model depends upon 5 quantities: -the cloud fractional coverage -the spectral slope -the mean value -the variance -the internal heterogeneity (intermittency). All these quantities are independantly identifiable on the base of mathematical proofs. This model also depends on a given function, called "morphlet", and on the law of a random variables family. In order to get a positive water contain inside the cloud,we ask the morphlet and the random variables to be positives. The structure of the model is hierarchycal. The vertebral column of this model is a tree: the basic encoding tree of the space where the cloud lives. At each edge of the tree is attached: -a Bernoulli random variable,this for tuning the fractional cover and the intermittency, -a rate of energy loose,giving the spectral slope, -a dilated morphlet. The word flexible is justified by the fact that we can choose to modify some objets on the basic tree in order to adjust the caracteristics of the desired cloud.

  5. Advanced solderless flexible thermal link

    NASA Astrophysics Data System (ADS)

    Williams, Brian G.; Jensen, Scott M.; Batty, J. Clair

    1996-10-01

    Flexible thermal links play an important role int he thermal management of cryogenically cooled components. The purpose of these links is to provide a means of transferring heat from a cooled component to a cooler reservoir with little increase in temperature. The standard soldered approach although effective proves to be time consuming and contributes to added thermal impedances which degrade the performance of the link. For system with little tolerance for temperature differences between cooled components and a cooling source this is undesirable. The authors of this paper have developed a technique by which thin metal foil or braided wire can be attached to metal end blocks without any solder using the swaging process. Swaging provides a fast, simple method for providing a low thermal impedance between the foils and blocks. This paper describes the characteristics of these thermal links in terms of length, mass, thermal resistance, flexibility, and survivability.

  6. Fully Integral, Flexible Composite Driveshaft

    NASA Technical Reports Server (NTRS)

    Lawrie, Duncan

    2014-01-01

    An all-composite driveshaft incorporating integral flexible diaphragms was developed for prime contractor testing. This new approach makes obsolete the split lines required to attach metallic flex elements and either metallic or composite spacing tubes in current solutions. Subcritical driveshaft weights can be achieved that are half that of incumbent technology for typical rotary wing shaft lengths. Spacing tubes compose an integral part of the initial tooling but remain part of the finished shaft and control natural frequencies and torsional stability. A concurrently engineered manufacturing process and design for performance competes with incumbent solutions at significantly lower weight and with the probability of improved damage tolerance and fatigue life.

  7. Unusually Flexible Indium(III) Metal-Organic Polyhedra Materials for Detecting Trace Amounts of Water in Organic Solvents and High Proton Conductivity.

    PubMed

    Du, Xi; Fan, Ruiqing; Qiang, Liangsheng; Song, Yang; Xing, Kai; Chen, Wei; Wang, Ping; Yang, Yulin

    2017-03-06

    Humidity-induced single-crystal transformation was observed in the indium metal-organic polyhedra [In2(TCPB)2]·2H2O (In1), where H3TCPB is 1,3,5-tri(4-carboxyphenoxy)benzene. When the humidity is above 58% relative humidity (RH) at room temperature, the neutral compound In1 could be successfully converted into the positively charged compound In1-H along with the color change from yellow to deep red, which also undergoes a reversible transformation into In1 driven by thermal dehydration. Notably, the color of In1 takes only 5 min to change under 58% RH at room temperature, which is much quicker than common desiccant bluestone. As the water content is increased from 0.0% to 0.2% in acetonitrile solvent, compound In1 exhibits rapid detection of trace amounts of water through turn-off luminescence sensing mechanism with a low detection limit of 2.95 × 10(-4)%. Because of the formation of extensive hydrogen-bonding network between the metal-organic polyhedra (MOPs) and surrounding guest OH(-) ions, compound In1-H, along with isostructural Ga1-H, displays excellent proton conductivity up to 2.84 × 10(-4) and 2.26 × 10(-4) S cm(-1) at 298 K and 98% RH, respectively. Furthermore, the activation energies are found to be 0.28 eV for In1-H and 0.34 eV for Ga1-H. This method of incorporation of OH(-) ions to obtain high proton conductivity MOPs with low activation energy demonstrates the advantage of OH(-) ion conduction in the solid-state materials.

  8. Flexible, FEP-Teflon covered solar cell module development

    NASA Technical Reports Server (NTRS)

    Rauschenbach, H. S.; Cannady, M. D.

    1976-01-01

    Techniques and equipment were developed for the large scale, low-cost fabrication of lightweight, roll-up and fold-up, FEP-Teflon encapsulated solar cell modules. Modules were fabricated by interconnecting solderless single-crystal silicon solar cells and heat laminating them at approximately 300 C between layers of optically clear FEP and to a loadbearing Kapton substrate sheet. Modules were fabricated from both conventional and wraparound contact solar cells. A heat seal technique was developed for mechanically interconnecting modules into an array. The electrical interconnections for both roll-up and fold-up arrays were also developed. The use of parallel-gap resistance welding, ultrasonic bonding, and thermocompression bonding processes for attaching interconnects to solar cells were investigated. Parallel-gap welding was found to be best suited for interconnecting the solderless solar cells into modules. Details of the fabrication equipment, fabrication processes, module and interconnect designs, environmental test equipment, and test results are presented.

  9. 21 CFR 882.5250 - Burr hole cover.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identification. A burr hole cover is a plastic or metal device used to cover or plug holes drilled into the skull during surgery and to reattach cranial bone removed during surgery. (b) Classification. Class II...

  10. 21 CFR 882.5250 - Burr hole cover.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identification. A burr hole cover is a plastic or metal device used to cover or plug holes drilled into the skull during surgery and to reattach cranial bone removed during surgery. (b) Classification. Class II...

  11. 21 CFR 882.5250 - Burr hole cover.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identification. A burr hole cover is a plastic or metal device used to cover or plug holes drilled into the skull during surgery and to reattach cranial bone removed during surgery. (b) Classification. Class II...

  12. 21 CFR 882.5250 - Burr hole cover.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. A burr hole cover is a plastic or metal device used to cover or plug holes drilled into the skull during surgery and to reattach cranial bone removed during surgery. (b) Classification. Class...

  13. Electro Spray Method for Flexible Display

    DTIC Science & Technology

    2016-05-12

    AFRL-AFOSR-JP-TR-2016-0095 Electro Spray Method for Flexible Display Yukiharu Uraoka NARA INSTITUTE OF SCIENCE AND TECHNOLOGY Final Report 11/26/2016...DISTRIBUTION A: Distribution approved for public release. AF Office Of Scientific Research (AFOSR)/ IOA Arlington, Virginia 22203 Air Force Research...DATES COVERED (From - To)  20 Mar 2013 to 19 May 2016 4. TITLE AND SUBTITLE Electro Spray Method for Flexible Display 5a.  CONTRACT NUMBER 5b.  GRANT

  14. Eddy current probe with foil sensor mounted on flexible probe tip and method of use

    DOEpatents

    Viertl, John R. M.; Lee, Martin K.

    2001-01-01

    A pair of copper coils are embedded in the foil strip. A first coil of the pair generates an electromagnetic field that induces eddy currents on the surface, and the second coil carries a current influenced by the eddy currents on the surface. The currents in the second coil are analyzed to obtain information on the surface eddy currents. An eddy current probe has a metal housing having a tip that is covered by a flexible conductive foil strip. The foil strip is mounted on a deformable nose at the probe tip so that the strip and coils will conform to the surface to which they are applied.

  15. Copper Nanowires and Their Applications for Flexible, Transparent Conducting Films: A Review

    PubMed Central

    Nam, Vu Binh; Lee, Daeho

    2016-01-01

    Cu nanowires (NWs) are attracting considerable attention as alternatives to Ag NWs for next-generation transparent conductors, replacing indium tin oxide (ITO) and micro metal grids. Cu NWs hold great promise for low-cost fabrication via a solution-processed route and show preponderant optical, electrical, and mechanical properties. In this study, we report a summary of recent advances in research on Cu NWs, covering the optoelectronic properties, synthesis routes, deposition methods to fabricate flexible transparent conducting films, and their potential applications. This review also examines the approaches on protecting Cu NWs from oxidation in air environments. PMID:28344304

  16. Four 1-D metal-organic polymers self-assembled from semi-flexible benzimidazole-based ligand: Syntheses, structures and fluorescent properties

    NASA Astrophysics Data System (ADS)

    Zhou, Chun-lin; Wang, Shi-min; Liu, Sai-nan; Yu, Tian-tian; Li, Rui-ying; Xu, Hong; Liu, Zhong-yi; Sun, Huan; Cheng, Jia-jia; Li, Jin-peng; Hou, Hong-wei; Chang, Jun-biao

    2016-08-01

    Four one-dimensional (1-D) metal-organic polymers based on methylene-bis(1,1‧-benzimidazole)(mbbz), namely, {[Hg(mbbz)(SCN)2]·1/3H2O}n (1), [Co(mbbz)(Cl)2]n (2), {[Co(mbbz)(SO4)]·CH3OH}n (3) and {[Zn(mbbz)(SO4)]·CH3OH}n (4) have been successfully synthesized and structurally characterized. Single-crystal X-ray diffraction reveals that polymers 1 and 2 exhibit interesting 1-D double helical chain structures, while polymers 3 and 4 are 1-D double chain structures due to the bridging effect of mbbz ligands and sulfate anions. These polymers containing the mbbz-based ligand have a high degree of dependence on the corresponding counter anions. Furthermore, the fluorescence properties of the four polymers were also investigated in the solid state, showing the fluorescence signal changes in comparing with that of free ligand mbbz.

  17. Vibronic states in organic semiconductors based on non-metal naphthalocyanine. Detection of heterocyclic phthalocyanine compounds in a flexible dielectric matrix

    SciTech Connect

    Belogorokhov, I. A.; Tikhonov, E. V.; Dronov, M. A.; Belogorokhova, L. I.; Ryabchikov, Yu. V.; Tomilova, L. G.; Khokhlov, D. R.

    2012-01-15

    The vibronic properties of semiconductor structures based on non-metal naphthalocyanine molecules are studied using IR and Raman spectroscopy methods. New absorption lines in the transmission spectra of such materials are detected and identified. Three transmission lines are observed in the range 2830-3028 cm{sup -1}, which characterize carbon-hydrogen bonds of peripheral molecular groups. Their spectral positions are 2959, 2906, and 2866 cm{sup -1}. It is detected that the phthalocyanine ring can also exhibit its specific vibronic properties in the Raman spectra at 767, 717, and 679 cm{sup -1}. The naphthalocyanine molecule in the organic dielectric matrix of microfibers is described using IR spectroscopy. It is shown that the set of vibrations characterizing the isoindol group, pyrrole ring, naphtha group, and C-H bonds, allows an accurate enough description of the vibronic states of the naphthalocyanine complex in complex heterostructures to be made. The spectral range with fundamental modes, characterizing a naphthalocyanine semiconductor in a heterostructure, is 600-1600 cm{sup -1}. A comparison of the compositions of complex systems with a similar heterostructure containing lutetium diphthalocyanine demonstrated few errors.

  18. Assessing temporal trends of trace metal concentrations in mosses over France between 1996 and 2011: A flexible and robust method to account for heterogeneous sampling strategies.

    PubMed

    Lequy, Emeline; Dubos, Nicolas; Witté, Isabelle; Pascaud, Aude; Sauvage, Stéphane; Leblond, Sébastien

    2017-01-01

    Air quality biomonitoring has been successfully assessed using mosses for decades in Europe, particularly regarding heavy metals (HM). Assessing robust temporal variations of HM concentrations in mosses requires to better understand to what extent they are affected by the sampling protocol and the moss species. This study used the concentrations of 14 elements measured during four surveys over 15 years in France. Analyses of variance (ANOVA) and a modeling approach were used to decipher temporal variations for each element and adjust them with parameters known to affect concentrations. ANOVA followed by post hoc analyses did not allow to estimate clear trends. A generalized additive mixed modeling approach including the sampling period, the collector and the moss species, plus quadratic effects, was used to analyze temporal variations on repeated sampling sites. This approach highlighted the importance of accounting for non-linear temporal variations in HM, and adjusting for confounding factors such as moss species, species-specific differences between sampling periods, collector and methodological differences in sampling campaigns. For instance, lead concentrations in mosses decreased between 1996 and 2011 following quadratic functions, with faster declines for the most contaminated sites in 1996. On the other hand, other HM showed double trends with U-shaped or hill-shaped curves. The effect of the moss was complex to handle and our results advocate for using one moss species by repeated site to better analyze temporal variations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Fast flexible electronics using transferrable silicon nanomembranes

    NASA Astrophysics Data System (ADS)

    Zhang, Kan; Seo, Jung-Hun; Zhou, Weidong; Ma, Zhenqiang

    2012-04-01

    A systematic review, covering the aspects of material preparation, device fabrication and process integration, is provided for flexible electronics operating in high-frequency domain based on transferrable monocrystalline silicon (Si) nanomembranes (NM). Previously demonstrated methods of releasing Si NM from silicon-on-insulator source substrates and transferring it to flexible substrates are briefly described. Due to the processing temperature limitation of most flexible substrates, a pre-release NM selective doping scheme is used for Si NMs. With proper selections of ion implantation energy and dose, fully doped Si NMs across their entire thickness with very low sheet resistivity can be obtained, allowing flip transfer of the NMs for backside and even double side processing. A general conclusion of preferred low implantation energy for shallower depth ion implantation is identified. The evolvement of radio frequency (RF) flexible Si thin-film transistor (TFT) structures is described in detail. The continuous performance enhancement of TFTs owing to process and TFT structure innovations is analysed. Demonstrations of flexible Si RF switches and RF inductors and capacitors are also briefly reviewed as valuable components of the general flexible device family, some of which also benefit from the pre-release NM doping technique. With the proved feasibility of these basic RF elements and related processing techniques, more complicated flexible RF circuits can be expected. Future research directions are also discussed, including further enhancement of device performance, building more types of semiconductor devices on flexible substrates, and process integration for flexible circuits and systems.

  20. Passivation coating for flexible substrate mirrors

    DOEpatents

    Tracy, C. Edwin; Benson, David K.

    1990-01-01

    A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors. Also, the silver or other reflective metal layer on mirrors comprising thin, lightweight, flexible substrates of metal or polymer sheets coated with glassy layers can be protected with silicon nitride according to this invention.

  1. Balance and flexibility.

    PubMed

    2003-12-01

    The 'work-life balance' and flexible working are currently key buzz terms in the NHS. Those looking for more information on these topics should visit Flexibility at www.flexibility.co.uk for a host of resources designed to support new ways of working, including information on flexible workers and flexible rostering, the legal balancing act for work-life balance and home working.

  2. Cover/Frequency (CF)

    Treesearch

    John F. Caratti

    2006-01-01

    The FIREMON Cover/Frequency (CF) method is used to assess changes in plant species cover and frequency for a macroplot. This method uses multiple quadrats to sample within-plot variation and quantify statistically valid changes in plant species cover, height, and frequency over time. Because it is difficult to estimate cover in quadrats for larger plants, this method...

  3. Estimating Cloud Cover

    ERIC Educational Resources Information Center

    Moseley, Christine

    2007-01-01

    The purpose of this activity was to help students understand the percentage of cloud cover and make more accurate cloud cover observations. Students estimated the percentage of cloud cover represented by simulated clouds and assigned a cloud cover classification to those simulations. (Contains 2 notes and 3 tables.)

  4. Estimating Cloud Cover

    ERIC Educational Resources Information Center

    Moseley, Christine

    2007-01-01

    The purpose of this activity was to help students understand the percentage of cloud cover and make more accurate cloud cover observations. Students estimated the percentage of cloud cover represented by simulated clouds and assigned a cloud cover classification to those simulations. (Contains 2 notes and 3 tables.)

  5. Flexible non-diffractive vortex microscope for three-dimensional depth-enhanced super-localization of dielectric, metal and fluorescent nanoparticles

    NASA Astrophysics Data System (ADS)

    Bouchal, Petr; Bouchal, Zdeněk

    2017-10-01

    In the past decade, probe-based super-resolution using temporally resolved localization of emitters became a groundbreaking imaging strategy in fluorescence microscopy. Here we demonstrate a non-diffractive vortex microscope (NVM), enabling three-dimensional super-resolution fluorescence imaging and localization and tracking of metal and dielectric nanoparticles. The NVM benefits from vortex non-diffractive beams (NBs) creating a double-helix point spread function that rotates under defocusing while maintaining its size and shape unchanged. Using intrinsic properties of the NBs, the dark-field localization of weakly scattering objects is achieved in a large axial range exceeding the depth of field of the microscope objective up to 23 times. The NVM was developed using an upright microscope Nikon Eclipse E600 operating with a spiral lithographic mask optimized using Fisher information and built into an add-on imaging module or microscope objective. In evaluation of the axial localization accuracy the root mean square error below 18 nm and 280 nm was verified over depth ranges of 3.5 μm and 13.6 μm, respectively. Subwavelength gold and polystyrene beads were localized with isotropic precision below 10 nm in the axial range of 3.5 μm and the axial precision reduced to 30 nm in the extended range of 13.6 μm. In the fluorescence imaging, the localization with isotropic precision below 15 nm was demonstrated in the range of 2.5 μm, whereas in the range of 8.3 μm, the precision of 15 nm laterally and 30–50 nm axially was achieved. The tracking of nanoparticles undergoing Brownian motion was demonstrated in the volume of 14 × 10 × 16 μm3. Applicability of the NVM was tested by fluorescence imaging of LW13K2 cells and localization of cellular proteins.

  6. The tunable coordination architectures of a flexible multicarboxylate N-(4-carboxyphenyl)iminodiacetic acid via different metal ions, pH values and auxiliary ligand

    SciTech Connect

    Chai Xiaochuan; Zhang Hanhui; Zhang Shuai; Cao Yanning; Chen Yiping

    2009-07-15

    {l_brace}[Pb{sub 3}(CPIDA){sub 2}(H{sub 2}O){sub 3}].H{sub 2}O{r_brace}{sub n}1, {l_brace}[Cd{sub 3}(CPIDA){sub 2}(H{sub 2}O){sub 4}].5H{sub 2}O{r_brace}{sub n}2, [Cd(HCPIDA)(bpy)(H{sub 2}O)]{sub n}3 (bpy=4,4'-bipyridine) and {l_brace}[Co{sub 3}(CPIDA){sub 2}(bpy){sub 3}(H{sub 2}O){sub 4}].2H{sub 2}O{r_brace}{sub n}4 were synthesized with N-(4-carboxyphenyl) iminodiacetic acid (H{sub 3}CPIDA). In 1, the CPIDA{sup 3-} ligands adopt chelating and bridging modes with Pb(II) to possess a 3D porous framework. In 2D-layer 2, the CPIDA{sup 3-} ligands display a simple bridging mode with Cd(II). The 2D layers have parallelogram-shaped channels along a axis. With bpy ligands, the HCPIDA{sup 2-} ligands in 3 show more abundant modes, but 3 still displays a 2D sheet on bc plane for the unidentate bpy molecules. However, in 3D-framework 4, the bpy ligands adopt bridging bidentate at a higher pH value and the CPIDA{sup 3-} ligands show bis-bidentate modes with Co(II). Additionally, 2D correlation analysis of FTIR was introduced to ascertain the characteristic adsorptions location of the carboxylate groups with different coordination modes in 4 with thermal and magnetic perturbation. Compounds 1, 2 and 4 exhibit the fluorescent emissions at room temperature. - Graphical abstract: A series of coordination polymers were synthesized with H{sub 3}CPIDA and transition metal ions at lower pH values. The figure displays a 3D porous framework with three parallel channels in compound 1.

  7. Metal-controlled assembly tuning the topology and dimensionality of coordination polymers of Ag(I), Cd(II) and Zn(II) with the flexible 2-(1 H-imidazole-1-yl)acetic acid (Hima)

    NASA Astrophysics Data System (ADS)

    Wang, Yong-Tao; Tang, Gui-Mei; Wu, Yue; Qin, Xu-Yan; Qin, Da-Wei

    2007-04-01

    Three new, inorganic-organic coordination polymers based on a versatile linking unit 2-(1 H-imidazole-1-yl)acetate (ima) and Ag I, Cd II and Zn II ions, exhibiting one to three dimensionalities and different topology structures, have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of AgNO 3 with Hima afforded a neutral one-dimensional (1-D) chains [Ag(ima)] n ( 1) which exhibits a pseudo two-dimensional (2-D) layered architecture through π-π stacking interaction between imidazole rings and intermolecular Ag⋯Ag interactions. Reaction of CdCl 2 with Hima yielded neutral 2-D coordination polymers [Cd(ima) 2] n ( 2) possessing (6, 3) topology structures, which further stack into 3-D supramolecular networks through C-H⋯O weak interactions. While Zn(NO 3) 2 was used, a non-centric 3-D coordination polymer [Zn(ima) 2] n ( 3) featuring a 3-fold interpenetrating diamondoid net was isolated. Among these polymers, the building block ima anion exhibits different coordination modes. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal ions, play a critical role in construction of these novel coordination polymers. The spectral, thermal and SHG (second-harmonic generation) properties of these new materials have also been investigated.

  8. Biaxially textured cobalt-doped BaFe{sub 2}As{sub 2} films with high critical current density over 1 MA/cm{sup 2} on MgO-buffered metal-tape flexible substrates

    SciTech Connect

    Katase, Takayoshi; Hiramatsu, Hidenori; Kamiya, Toshio; Matias, Vladimir; Sheehan, Chris; Ishimaru, Yoshihiro; Tanabe, Keiichi; Hosono, Hideo

    2011-06-13

    High critical current densities (J{sub c})>1 MA/cm{sup 2} were realized in cobalt-doped BaFe{sub 2}As{sub 2} (BaFe{sub 2}As{sub 2}:Co) films on flexible metal substrates with biaxially textured MgO base-layers fabricated by an ion-beam assisted deposition technique. The BaFe{sub 2}As{sub 2}:Co films showed small in-plane crystalline misorientations ({Delta}{phi}{sub BaFe2As2:Co}) of {approx}3 deg. regardless of twice larger misorientations of the MgO base-layers ({Delta}{phi}{sub MgO}=7.3 deg.), and exhibited high self-field J{sub c} up to 3.5 MA/cm{sup 2} at 2 K. These values are comparable to that on MgO single crystals and the highest J{sub c} among iron pnictide superconducting tapes and wires ever reported. High in-field J{sub c} suggests the existence of c-axis correlated vortex pinning centers.

  9. Vehicle body cover

    SciTech Connect

    Hirose, T.

    1987-01-13

    This patent describes a vehicle body covered with a vehicle body cover which comprises: a front cover part, a rear cover part, a pair of side cover parts, and a roof cover part: the front cover part having portions adapted to cover only a hood, an area around a windshield and tops of front fenders of a vehicle body. The portion covering the hood is separated from the portions covering the tops of the fenders by cuts in the front cover part, the front cover part having an un-cut portion corresponding to a position at which the hood is hinged to the car body. The front cover part has a cut-out at a position corresponding to the windshield of the vehicle body and the front cover part has at least one cut-out at a position corresponding to where a rear view mirror is attached to the vehicle body; and the rear cover part having portions adapted to cover an area around a rear window, a trunk lid and a rear end of the vehicle body, the portion covering the trunk lid separated from the rest of the rear cover part by cuts corresponding to three sides of the trunk lid and an un-cut portion corresponding to a position at which the trunk lid is hinged to the vehicle body. The rear cover part has a hole at position corresponding to a trunk lid lock, a cut-out portion at a position corresponding to the rear window of the vehicle body, a cut-out at a position corresponding to a license plate of the vehicle body and cut-outs at positions corresponding to rear taillights of the vehicle body.

  10. Multiple layer insulation cover

    DOEpatents

    Farrell, James J.; Donohoe, Anthony J.

    1981-11-03

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  11. Flexible packaging and integration of CMOS IC with elastomeric microfluidics

    NASA Astrophysics Data System (ADS)

    Zhang, Bowei; Dong, Quan; Korman, Can E.; Li, Zhenyu; Zaghloul, Mona E.

    2013-05-01

    We have demonstrated flexible packaging and integration of CMOS IC chips with PDMS microfluidics. Microfluidic channels are used to deliver both liquid samples and liquid metals to the CMOS die. The liquid metals are used to realize electrical interconnects to the CMOS chip. As a demonstration we integrated a CMOS magnetic sensor die and matched PDMS microfluidic channels in a flexible package. The packaged system is fully functional under 3cm bending radius. The flexible integration of CMOS ICs with microfluidics enables previously unavailable flexible CMOS electronic systems with fluidic manipulation capabilities, which hold great potential for wearable health monitoring, point-of-care diagnostics and environmental sensing.

  12. 75 FR 6597 - Determination to Approve Alternative Final Cover Request for the Lake County, MT Landfill...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-10

    .... The pilot test consisted of the construction of two landfill cover test plots at the Lake County landfill facility. One plot used a landfill cover design with a flexible membrane liner, and the other plot...

  13. Mekong Land Cover Dasboard: Regional Land Cover Mointoring Systems

    NASA Astrophysics Data System (ADS)

    Saah, D. S.; Towashiraporn, P.; Aekakkararungroj, A.; Phongsapan, K.; Triepke, J.; Maus, P.; Tenneson, K.; Cutter, P. G.; Ganz, D.; Anderson, E.

    2016-12-01

    SERVIR-Mekong, a USAID-NASA partnership, helps decision makers in the Lower Mekong Region utilize GIS and Remote Sensing information to inform climate related activities. In 2015, SERVIR-Mekong conducted a geospatial needs assessment for the Lower Mekong countries which included individual country consultations. The team found that many countries were dependent on land cover and land use maps for land resource planning, quantifying ecosystem services, including resilience to climate change, biodiversity conservation, and other critical social issues. Many of the Lower Mekong countries have developed national scale land cover maps derived in part from remote sensing products and geospatial technologies. However, updates are infrequent and classification systems do not always meet the needs of key user groups. In addition, data products stop at political boundaries and are often not accessible making the data unusable across country boundaries and with resource management partners. Many of these countries rely on global land cover products to fill the gaps of their national efforts, compromising consistency between data and policies. These gaps in national efforts can be filled by a flexible regional land cover monitoring system that is co-developed by regional partners with the specific intention of meeting national transboundary needs, for example including consistent forest definitions in transboundary watersheds. Based on these facts, key regional stakeholders identified a need for a land cover monitoring system that will produce frequent, high quality land cover maps using a consistent regional classification scheme that is compatible with national country needs. SERVIR-Mekong is currently developing a solution that leverages recent developments in remote sensing science and technology, such as Google Earth Engine (GEE), and working together with production partners to develop a system that will use a common set of input data sources to generate high

  14. Cover Your Cough

    MedlinePlus

    ... as PDF files. Cover Your Cough, Flyer for Health Care Settings English [324 KB] English (no logo) [281 KB] Cover Your Cough, Flyer & Poster for Health Care Settings Flyer : English Portuguese [268 KB] French [225 ...

  15. What Medicare Covers

    MedlinePlus

    ... your Medicare coverage — Original Medicare or a Medicare Advantage Plan (Part C). What Part A covers Medicare ... health plans cover Medicare health plans include Medicare Advantage, Medical Savings Account (MSA), Medicare Cost plans, PACE, ...

  16. Flexible thermal laminate

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Sauers, D. G.

    1977-01-01

    Lightweight flexible laminate of interwoven conducting and insulating yarns, designed to provide localized controlled heating for propellant tanks on space vehicles, is useful for nonspace applications where weight, bulk, and flexibility are critical concerns.

  17. Flexibility and Muscular Strength.

    ERIC Educational Resources Information Center

    Liemohn, Wendell

    1988-01-01

    This definition of flexibility and muscular strength also explores their roles in overall physical fitness and focuses on how increased flexibility and muscular strength can help decrease or eliminate lower back pain. (CB)

  18. Flexibility and Muscular Strength.

    ERIC Educational Resources Information Center

    Liemohn, Wendell

    1988-01-01

    This definition of flexibility and muscular strength also explores their roles in overall physical fitness and focuses on how increased flexibility and muscular strength can help decrease or eliminate lower back pain. (CB)

  19. Metallic Seal Development for Advanced Docking/Berthing System

    NASA Technical Reports Server (NTRS)

    Oswald, Jay; Daniels, Christopher; Dunlap, Patrick, Jr.; Steinetz, Bruce

    2006-01-01

    Feasibility of metal-to-metal androgenous seals has been demonstrated. Techniques to minimize surface irregularities must be examined. Two concepts investigated: 1) Flexible metal interface with elastomeric preloader; 2) Flexibility will accommodate any surface irregularities from the mating surface. Rigid metal interface with elastomeric preloader. Rigidity of the metal surface will prevent irregularities (waves) from occurring.

  20. Cover crop water use

    USDA-ARS?s Scientific Manuscript database

    Cover crops are being widely promoted because of soil health benefits. However, semi-arid dryland production systems, chronically short of water for crop production, may not be able to profitably withstand the yield reduction that follows cover crops because of cover crop water use. Some studies sug...

  1. Cover crops for Alabama

    USDA-ARS?s Scientific Manuscript database

    Cover crops are grown to benefit the following crop as well as to improve the soil, but they are normally not intended for harvest. Selecting the right cover crops for farming operations can improve yields, soil and water conservation and quality, and economic productivity. Properly managed cover ...

  2. Long-Term Outcomes of Double-Layered Polytetrafluoroethylene Membrane-Covered Self-Expandable Segmental Metallic Stents (Uventa) in Patients with Chronic Ureteral Obstructions: Is It Really Safe?

    PubMed

    Kim, Myong; Hong, Bumsik; Park, Hyung Keun

    2016-12-01

    To evaluate the long-term clinical efficacy and safety of double-layered polytetrafluoroethylene membrane-covered self-expandable segmental metallic stents (Uventa) in patients with chronic ureteral obstruction. In a retrospective study, a total of 50 ureter units (44 patients) with chronic obstructions were included from July 2010 to May 2015. Indications for Uventa placement were primary stenting for malignant ureteral obstruction, failed conventional polymeric Double-J stent (PS), or percutaneous nephrostomy (PCN) technique, with comorbidities or fears limiting PS/PCN changes, or with irritation or pain due to PS/PCN. Patients underwent Uventa stent placement using the antegrade or retrograde approach. There were no immediate procedure-related complications, and all stents were placed in the proper sites. During the median follow-up of 30.9 (interquartile range [IQR], 8.1-49.0) months, the primary (no obstruction and no additional intervention) and overall success (no obstruction and no additional intervention except supplementary Uventa) was 30.0% and 34.0%, respectively. Moreover, 14 of 50 ureter units (28.0%) experienced major complications (≥Clavien-Dindo class IIIb), such as ureteroarterial fistula (three cases, 6.0%), ureteroenteric fistula (three, 6.0%), ureterovaginal fistula (one, 2.0%), ureter perforation (one, 2.0%), uncontrollable bleeding (one, 2.0%), and complete obstruction (five, 10.0%). On univariate analysis, major complications were associated with female (odds ratio [OR] = 6.000), cervical cancer (OR = 4.667), ureteral stricture length (≥6.0 cm, OR = 4.583), and placement duration (≥24.0 months, OR = 20.429; all p < 0.05). In long-term follow-up, the Uventa stent demonstrated poor treatment outcomes with frequent major complications in patients with chronic ureteral obstructions.

  3. Anchoring of a fully covered self-expandable metal stent with a 5F double-pigtail plastic stent to prevent migration in the management of benign biliary strictures.

    PubMed

    Park, Jong Kyu; Moon, Jong Ho; Choi, Hyun Jong; Min, Seul Ki; Lee, Tae Hoon; Cheon, Gab Jin; Cheon, Young Koog; Cho, Young Deok; Park, Sang-Heum; Kim, Sun-Joo

    2011-10-01

    Fully covered self-expandable metal stents (FCSEMSs) can be effectively placed in patients with benign biliary stricture (BBS). However, stent migration is an inherent problem of FCSEMSs. We evaluated the efficacy of anchoring with a 5F double-pigtail plastic stent (anchoring stent) to prevent migration of an FCSEMS in patients with BBS. Between January 2007 and December 2009, 33 of 37 consecutive patients with BBS who had experienced treatment failure of at least one plastic stent placement were prospectively enrolled in this study. The patients with BBS were randomly assigned to undergo FCSEMS placement with or without an anchoring stent (anchoring group: 16 patients; non-anchoring group: 17 patients). The main outcome measures were the stent migration rate and success rates. The technical success rate was 100% in both groups. Significantly less stent migration occurred in the anchoring group (6.3%, 1/16) than in the non-anchoring group (41.2%, 7/17; P=0.024). The median indwelling time was significantly longer in the anchoring group (154 days; range, 86-176 days) than in the non-anchoring group (114 days; range, 19-162 days; P=0.010). Improvement or resolution of the BBS was confirmed in 15 of 16 patients (93.8%) in the anchoring group, and in 12 of 17 patients (70.6%) in the non-anchoring group (P=0.101). The placement of an anchoring stent appears to be a simple and effective method of preventing premature migration of FCSEMSs in patients with BBS. Appropriately powered studies are needed to confirm this finding.

  4. Evaluation of the short- and long-term effectiveness and safety of fully covered self-expandable metal stents for drainage of pancreatic fluid collections: results of a Spanish nationwide registry.

    PubMed

    Vazquez-Sequeiros, Enrique; Baron, Todd H; Pérez-Miranda, Manuel; Sánchez-Yagüe, Andres; Gornals, Joan; Gonzalez-Huix, Ferran; de la Serna, Carlos; Gonzalez Martin, Juan Angel; Gimeno-Garcia, Antonio Z; Marra-Lopez, Carlos; Castellot, Ana; Alberca, Fernando; Fernandez-Urien, Ignacio; Aparicio, Jose Ramon; Legaz, Maria Luisa; Sendino, Oriol; Loras, Carmen; Subtil, Jose Carlos; Nerin, Juan; Perez-Carreras, Mercedes; Diaz-Tasende, Jose; Perez, Gustavo; Repiso, Alejandro; Vilella, Angels; Dolz, Carlos; Alvarez, Alberto; Rodriguez, Santiago; Esteban, Jose Miguel; Juzgado, Diego; Albillos, Agustin

    2016-09-01

    Initial reports suggest that fully covered self-expandable metal stents (FCSEMSs) may be better suited for drainage of dense pancreatic fluid collections (PFCs), such as walled-off pancreatic necrosis. The primary aim was to analyze the effectiveness and safety of FCSEMSs for drainage of different types of PFCs in a large cohort. The secondary aim was to investigate which type of FCSEMS is superior. This was a retrospective, noncomparative review of a nationwide database involving all hospitals in Spain performing EUS-guided PFC drainage. From April 2008 to August 2013, all patients undergoing PFC drainage with an FCSEMS were included in a database. The main outcome measurements were technical success, short-term (2 weeks) and long-term (6 months) effectiveness, adverse events, and need for surgery. The study included 211 patients (pseudocyst/walled-off pancreatic necrosis, 53%/47%). The FCSEMSs used were straight biliary (66%) or lumen-apposing (34%). Technical success was achieved in 97% of patients (95% confidence interval [CI], 93%-99%). Short-term- and long-term clinical success was obtained in 94% (95% CI, 89%-97%) and 85% (95% CI, 79%-89%) of patients, respectively. Adverse events occurred in 21% of patients (95% CI, 16%-27%): infection (11%), bleeding (7%), and stent migration and/or perforation (3%). By multivariate analysis, patient age (>58 years) and previous failed drainage were the most important factors associated with negative outcome. An FCSEMS is effective and safe for PFC drainage. Older patients with a history of unsuccessful drainage are more likely to fail EUS-guided drainage. The type of FCSEMS does not seem to influence patient outcome. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  5. Endoscopic extra-cavitary drainage of pancreatic necrosis with fully covered self-expanding metal stents (fcSEMS) and staged lavage with a high-flow water jet system

    PubMed Central

    Smith, Ioana B.; Gutierrez, Juan P.; Ramesh, Jayapal; Wilcox, C. Mel; Mönkemüller, Klaus E.

    2015-01-01

    Aim: To present a novel, less-invasive method of endoscopic drainage (ED) for walled-off pancreatic necrosis (WON).We describe the feasibility, success rate, and complications of combined ED extra-cavitary lavage and debridement of WON using a biliary catheter and high-flow water jet system (water pump). Patients and methods: Endoscopic ultrasound (EUS)-guided drainage was performed with insertion of two 7-Fr, 4-cm double pigtail stents. Subsequently a fully covered self-expanding metal stent (fcSEMS) was placed. The key aspect of the debridement was the insertion of a 5-Fr biliary catheter through or along the fcSEMS into the cavity, with ensuing saline lavage using a high-flow water jet system. The patients were then brought back for repeated, planned endoscopic lavages of the WON. No endoscopic intra-cavitary exploration was performed. Results: A total of 17 patients (15 men, 2 women; mean age 52.6, range 24 – 69; mean American Society of Anesthesiologists [ASA] score of 3) underwent ED of WON with this new method. The mean initial WON diameter was 9.5 cm, range 8 to 26 cm. The total number of ED was 84, range 2 to 13. The mean stenting period was 42.5 days. The mean follow-up was 51 days, range 3 to 370. A resolution of the WON was achieved in 14 patients (82.3 %). There were no major complications associated with this method. Conclusion: ED of complex WON with fcSEMS followed by repeated endoscopic extra-cavitary lavage and debridement using a biliary catheter and high-flow water jet system is a minimally invasive, feasible method with high technical and clinical success and minimal complications. PMID:26135660

  6. Endoscopic extra-cavitary drainage of pancreatic necrosis with fully covered self-expanding metal stents (fcSEMS) and staged lavage with a high-flow water jet system.

    PubMed

    Smith, Ioana B; Gutierrez, Juan P; Ramesh, Jayapal; Wilcox, C Mel; Mönkemüller, Klaus E

    2015-04-01

    To present a novel, less-invasive method of endoscopic drainage (ED) for walled-off pancreatic necrosis (WON).We describe the feasibility, success rate, and complications of combined ED extra-cavitary lavage and debridement of WON using a biliary catheter and high-flow water jet system (water pump). Endoscopic ultrasound (EUS)-guided drainage was performed with insertion of two 7-Fr, 4-cm double pigtail stents. Subsequently a fully covered self-expanding metal stent (fcSEMS) was placed. The key aspect of the debridement was the insertion of a 5-Fr biliary catheter through or along the fcSEMS into the cavity, with ensuing saline lavage using a high-flow water jet system. The patients were then brought back for repeated, planned endoscopic lavages of the WON. No endoscopic intra-cavitary exploration was performed. A total of 17 patients (15 men, 2 women; mean age 52.6, range 24 - 69; mean American Society of Anesthesiologists [ASA] score of 3) underwent ED of WON with this new method. The mean initial WON diameter was 9.5 cm, range 8 to 26 cm. The total number of ED was 84, range 2 to 13. The mean stenting period was 42.5 days. The mean follow-up was 51 days, range 3 to 370. A resolution of the WON was achieved in 14 patients (82.3 %). There were no major complications associated with this method. ED of complex WON with fcSEMS followed by repeated endoscopic extra-cavitary lavage and debridement using a biliary catheter and high-flow water jet system is a minimally invasive, feasible method with high technical and clinical success and minimal complications.

  7. Thinking about Flexibility

    ERIC Educational Resources Information Center

    Villa, Mario Diaz

    2009-01-01

    This article emphasizes the complexity of the term flexibility and discusses its meanings and political dimensions, along with its expressions or realizations within the field of higher education. It proposes a new principle of flexibility that overcomes an understanding of flexibility within higher education as the mere ability or versatility to…

  8. Thinking about Flexibility

    ERIC Educational Resources Information Center

    Villa, Mario Diaz

    2009-01-01

    This article emphasizes the complexity of the term flexibility and discusses its meanings and political dimensions, along with its expressions or realizations within the field of higher education. It proposes a new principle of flexibility that overcomes an understanding of flexibility within higher education as the mere ability or versatility to…

  9. Cost averaging techniques for robust control of flexible structural systems

    NASA Technical Reports Server (NTRS)

    Hagood, Nesbitt W.; Crawley, Edward F.

    1991-01-01

    Viewgraphs on cost averaging techniques for robust control of flexible structural systems are presented. Topics covered include: modeling of parameterized systems; average cost analysis; reduction of parameterized systems; and static and dynamic controller synthesis.

  10. Inhibiting multiple mode vibration in controlled flexible systems

    NASA Technical Reports Server (NTRS)

    Hyde, James M.; Chang, Kenneth W.; Seering, Warren P.

    1991-01-01

    Viewgraphs on inhibiting multiple mode vibration in controlled flexible systems are presented. Topics covered include: input pre-shaping background; developing multiple-mode shapers; Middeck Active Control Experiment (MACE) test article; and tests and results.

  11. Orthogonal flexible Rydberg aggregates

    NASA Astrophysics Data System (ADS)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  12. 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

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Huang, Xianjun; Pan, Kewen; Hu, Zhirun

    2016-12-01

    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.

  15. All-Printed Flexible and Stretchable Electronics.

    PubMed

    Mohammed, Mohammed G; Kramer, Rebecca

    2017-03-01

    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.

  16. Final Report: Sintered CZTS Nanoparticle Solar Cells on Metal Foil; July 26, 2011 - July 25, 2012

    SciTech Connect

    Leidholm, C.; Hotz, C.; Breeze, A.; Sunderland, C.; Ki, W.; Zehnder, D.

    2012-09-01

    This is the final report covering 12 months of this subcontract for research on high-efficiency copper zinc tin sulfide (CZTS)-based thin-film solar cells on flexible metal foil. Each of the first three quarters of the subcontract has been detailed in quarterly reports. In this final report highlights of the first three quarters will be provided and details will be given of the final quarter of the subcontract.

  17. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Inspection and cover plates. 57.12032 Section 57.12032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on...

  18. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Inspection and cover plates. 57.12032 Section 57.12032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on...

  19. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Inspection and cover plates. 57.12032 Section 57.12032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on...

  20. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Inspection and cover plates. 57.12032 Section 57.12032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on...

  1. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Inspection and cover plates. 57.12032 Section 57.12032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on...

  2. 21 CFR 882.5250 - Burr hole cover.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Burr hole cover. 882.5250 Section 882.5250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...) Identification. A burr hole cover is a plastic or metal device used to cover or plug holes drilled into the skull...

  3. Some Investigations of the General Instability of Stiffened Metal Cylinders IV : Continuation of Tests of Sheet-covered Specimens and Studies of the Buckling Phenomena of Unstiffened Circular Cylinders

    NASA Technical Reports Server (NTRS)

    1943-01-01

    This is the fourth of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report is to deal primarily with the continuation of tests of sheet-covered specimens and studies of the buckling phenomena of unstiffened circular cylinders.

  4. National land cover dataset

    USGS Publications Warehouse

    ,

    2000-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency, has produced a land cover dataset for the conterminous United States on the basis of 1992 Landsat thematic mapper imagery and supplemental data. The National Land Cover Dataset (NLCD) is a component of the USGS Land Cover Characterization Program. The seamless NLCD contains 21 categories of land cover information suitable for a variety of State and regional applications, including landscape analysis, land management, and modeling nutrient and pesticide runoff. The NLCD is distributed by State as 30-meter resolution raster images in an Albers Equal-Area map projection.

  5. Armored geomembrane cover engineering.

    PubMed

    Foye, Kevin

    2011-06-01

    Geomembranes are an important component of modern engineered barriers to prevent the infiltration of stormwater and runoff into contaminated soil and rock as well as waste containment facilities--a function generally described as a geomembrane cover. This paper presents a case history involving a novel implementation of a geomembrane cover system. Due to this novelty, the design engineers needed to assemble from disparate sources the design criteria for the engineering of the cover. This paper discusses the design methodologies assembled by the engineering team. This information will aid engineers designing similar cover systems as well as environmental and public health professionals selecting site improvements that involve infiltration barriers.

  6. Armored Geomembrane Cover Engineering

    PubMed Central

    Foye, Kevin

    2011-01-01

    Geomembranes are an important component of modern engineered barriers to prevent the infiltration of stormwater and runoff into contaminated soil and rock as well as waste containment facilities—a function generally described as a geomembrane cover. This paper presents a case history involving a novel implementation of a geomembrane cover system. Due to this novelty, the design engineers needed to assemble from disparate sources the design criteria for the engineering of the cover. This paper discusses the design methodologies assembled by the engineering team. This information will aid engineers designing similar cover systems as well as environmental and public health professionals selecting site improvements that involve infiltration barriers. PMID:21776229

  7. A non-randomized study in consecutive patients with postcholecystectomy refractory biliary leaks who were managed endoscopically with the use of multiple plastic stents or fully covered self-expandable metal stents (with videos).

    PubMed

    Canena, Jorge; Liberato, Manuel; Meireles, Liliane; Marques, Inês; Romão, Carlos; Coutinho, António Pereira; Neves, Beatriz Costa; Veiga, Pedro Mota

    2015-07-01

    Endoscopic management of postcholecystectomy biliary leaks is widely accepted as the treatment of choice. However, refractory biliary leaks after a combination of biliary sphincterotomy and the placement of a large-bore (10F) plastic stent can occur, and the optimal rescue endotherapy for this situation is unclear. To compare the clinical effectiveness of the use of a fully covered self-expandable metal stent (FCSEMS) with the placement of multiple plastic stents (MPS) for the treatment of postcholecystectomy refractory biliary leaks. Prospective study. Two tertiary-care referral academic centers and one general district hospital. Forty consecutive patients with refractory biliary leaks who underwent endoscopic management. Temporary placement of MPS (n = 20) or FCSEMSs (n = 20). Clinical outcomes of endotherapy as well as the technical success, adverse events, need for reinterventions, and prognostic factors for clinical success. Endotherapy was possible in all patients. After endotherapy, closure of the leak was accomplished in 13 patients (65%) who received MPS and in 20 patients (100%) who received FCSEMSs (P = .004). The Kaplan-Meier (log-rank) leak-free survival analysis showed a statistically significant difference between the 2 patient populations (χ(2) [1] = 8.30; P < .01) in favor of the FCSEMS group. Use of <3 plastic stents (P = .024), a plastic stent diameter <20F (P = .006), and a high-grade biliary leak (P = .015) were shown to be significant predictors of treatment failure with MPS. The 7 patients in whom placement of MPS failed were retreated with FCSEMSs, resulting in closure of the leaks in all cases. Non-randomized design. In our series, the results of the temporary placement of FCSEMSs for postcholecystectomy refractory biliary leaks were superior to those from the use of MPS. A randomized study is needed to confirm our results before further recommendations. Copyright © 2015 American Society for Gastrointestinal Endoscopy

  8. Invertible flexible matrices

    NASA Astrophysics Data System (ADS)

    Justino, Júlia

    2017-06-01

    Matrices with coefficients having uncertainties of type o (.) or O (.), called flexible matrices, are studied from the point of view of nonstandard analysis. The uncertainties of the afore-mentioned kind will be given in the form of the so-called neutrices, for instance the set of all infinitesimals. Since flexible matrices have uncertainties in their coefficients, it is not possible to define the identity matrix in an unique way and so the notion of spectral identity matrix arises. Not all nonsingular flexible matrices can be turned into a spectral identity matrix using Gauss-Jordan elimination method, implying that that not all nonsingular flexible matrices have the inverse matrix. Under certain conditions upon the size of the uncertainties appearing in a nonsingular flexible matrix, a general theorem concerning the boundaries of its minors is presented which guarantees the existence of the inverse matrix of a nonsingular flexible matrix.

  9. Covered Bridge Security Manual

    Treesearch

    Brett Phares; Terry Wipf; Ryan Sievers; Travis Hosteng

    2013-01-01

    The design, construction, and use of covered timber bridges is all but a lost art in these days of pre-stressed concrete, high-performance steel, and the significant growth both in the volume and size of vehicles. Furthermore, many of the existing covered timber bridges are preserved only because of their status on the National Registry of Historic Places or the...

  10. Silostop Bunker Covers

    USDA-ARS?s Scientific Manuscript database

    The quality of the seal provided by the plastic cover is a key issue for minimizing losses in bunker and pile silos. Most bunker covers are 6 to 8 mil polyethylene sheets held in place by tires or tire sidewalls. Frequently there are problems with spoilage at the shoulders (i.e., against the walls),...

  11. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  12. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  13. Graphene Based Flexible Gas Sensors

    NASA Astrophysics Data System (ADS)

    Yi, Congwen

    Graphene is a novel carbon material with great promise for a range of applications due to its electronic and mechanical properties. Its two-dimensional nature translates to a high sensitivity to surface chemical interactions thereby making it an ideal platform for sensors. Graphene's electronic properties are not degraded due to mechanical flexing or strain (Kim, K. S., et al. nature 07719, 2009) offering another advantage for flexible sensors integrated into numerous systems including fabrics, etc. We have demonstrated a graphene NO2 sensor on a solid substrate (100nm SiO2/heavily doped silicon). Three different methods were used to synthesize graphene and the sensor fabrication process was optimized accordingly. Water is used as a controllable p-type dopant in graphene to study the relationship between doping and graphene's response to NO2 . Experimental results show that interface water between graphene and the supporting SiO2 substrate induces higher p-doping in graphene, leading to a higher sensitivity to NO2, consistent with theoretical predications (Zhang, Y. et al., Nanotechnology 20(2009) 185504). We have also demonstrated a flexible and stretchable graphene-based sensor. Few layer graphene, grown on a Ni substrate, is etched and transferred to a highly stretchable polymer substrate (VHB from 3M) with preloaded stress, followed by metal contact formation to construct a flexible, stretchable sensor. With up to 500% deformation caused by compressive stress, graphene still shows stable electrical response to NO2. Our results suggest that higher compressive stress results in smaller sheet resistance and higher sensitivity to NO2. A possible molecular detection sensor utilizing Surface Enhanced Raman Spectrum (SERS) based on a graphene/gallium nanoparticles platform is also studied. By correlating the enhancement of the graphene Raman modes with metal coverage, we propose that the Ga transfers electrons to the graphene creating local regions of enhanced

  14. Land Cover Trends Project

    USGS Publications Warehouse

    Acevedo, William

    2006-01-01

    The Land Cover Trends Project is designed to document the types, rates, causes, and consequences of land cover change from 1973 to 2000 within each of the 84 U.S. Environmental Protection Agency (EPA) Level III ecoregions that span the conterminous United States. The project's objectives are to: * Develop a comprehensive methodology using probability sampling and change analysis techniques and Landsat Multispectral Scanner (MSS), Thematic Mapper (TM), and Enhanced Thematic Mapper (ETM) data for estimating regional land cover change. * Characterize the spatial and temporal characteristics of conterminous U.S. land cover change for five periods from 1973 to 2000 (nominally 1973, 1980, 1986, 1992, and 2000). * Document the regional driving forces and consequences of change. * Prepare a national synthesis of land cover change.

  15. Flexible MEMS: A novel technology to fabricate flexible sensors and electronics

    NASA Astrophysics Data System (ADS)

    Tu, Hongen

    This dissertation presents the design and fabrication techniques used to fabricate flexible MEMS (Micro Electro Mechanical Systems) devices. MEMS devices and CMOS(Complementary Metal-Oxide-Semiconductor) circuits are traditionally fabricated on rigid substrates with inorganic semiconductor materials such as Silicon. However, it is highly desirable that functional elements like sensors, actuators or micro fluidic components to be fabricated on flexible substrates for a wide variety of applications. Due to the fact that flexible substrate is temperature sensitive, typically only low temperature materials, such as polymers, metals, and organic semiconductor materials, can be directly fabricated on flexible substrates. A novel technology based on XeF2(xenon difluoride) isotropic silicon etching and parylene conformal coating, which is able to monolithically incorporate high temperature materials and fluidic channels, was developed at Wayne State University. The technology was first implemented in the development of out-of-plane parylene microneedle arrays that can be individually addressed by integrated flexible micro-channels. These devices enable the delivery of chemicals with controlled temporal and spatial patterns and allow us to study neurotransmitter-based retinal prosthesis. The technology was further explored by adopting the conventional SOI-CMOS processes. High performance and high density CMOS circuits can be first fabricated on SOI wafers, and then be integrated into flexible substrates. Flexible p-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistors) were successfully integrated and tested. Integration of pressure sensors and flow sensors based on single crystal silicon has also been demonstrated. A novel smart yarn technology that enables the invisible integration of sensors and electronics into fabrics has been developed. The most significant advantage of this technology is its post-MEMS and post-CMOS compatibility. Various high

  16. Flexible inorganic nanowire light-emitting diode.

    PubMed

    Nadarajah, Athavan; Word, Robert C; Meiss, Jan; Könenkamp, Rolf

    2008-02-01

    We report a highly flexible light-emitting device in which inorganic nanowires are the optically active components. The single-crystalline ZnO nanowires are grown at 80 degrees C on flexible polymer-based indium-tin-oxide-coated substrates and subsequently encapsulated in a minimal-thickness, void-filling polystyrene film. A reflective top contact serving as the anode in the diode structure is provided by a strongly doped p-type polymer and an evaporated Au film. The emission through the polymer side of this arrangement covers most of the visual region. Electrical and optical properties as well as performance limitations of the device structure are discussed.

  17. Tunable dielectric liquid lens on flexible substrate

    PubMed Central

    Lu, Yen-Sheng; Tu, Hongen; Xu, Yong; Jiang, Hongrui

    2013-01-01

    We demonstrate the fabrication of a tunable-focus dielectric liquid lens (DLL) on a flexible substrate made of polydimethylsiloxane, which was wrapped onto a goggle surface to show its functionality. As a positive meniscus converging lens, the DLL has the focal length variable from 14.2 to 6.3 mm in 1.3 s when the driving voltage increases to 125 Vrms. The resolving power of the DLL is 17.95 line pairs per mm. The DLL on a flexible, curvilinear surface is promising for expanded field of view covered as well as in reconfigurable optical systems. PMID:24493877

  18. Flexible alternatives to constant frequency systems

    NASA Astrophysics Data System (ADS)

    Stewart-Wilson, John

    The use of hybrid systems in which variable frequency is used as generated, with a proportion being converted to constant frequency by electronic conversion, is examined as a flexible alternative to constant frequency systems. Here, some practical solutions to the technical issues raised by adopting the more flexible approach to electrical system generation are presented. In particular, attention is given to the frequency ranges used, impact on aircraft equipment, motor-driven equipment, transformer rectifier units, lighting, and avionics. The discussion also covers fan-assisted galley ovens, system architecture, special airworthiness requirements, and power quality.

  19. Metal Building Systems Fit To Be Tried

    ERIC Educational Resources Information Center

    Nation's Schools, 1974

    1974-01-01

    Describes the advantages of metal building systems in school construction. These advantages include faster occupancy, lower initial costs, reduced maintenance, flexibility, and predictability of cost. (Author/DN)

  20. Metal Building Systems Fit To Be Tried

    ERIC Educational Resources Information Center

    Nation's Schools, 1974

    1974-01-01

    Describes the advantages of metal building systems in school construction. These advantages include faster occupancy, lower initial costs, reduced maintenance, flexibility, and predictability of cost. (Author/DN)