Ultra smooth NiO thin films on flexible plastic (PET) substrate at room temperature by RF magnetron sputtering and effect of oxygen partial pressure on their properties

International Nuclear Information System (INIS)

Nandy, S.; Goswami, S.; Chattopadhyay, K.K.

2010-01-01

Transparent p-type nickel oxide thin films were grown on polyethylene terephthalate (PET) and glass substrates by RF magnetron sputtering technique in argon + oxygen atmosphere with different oxygen partial pressures at room temperature. The morphology of the NiO thin films grown on PET and glass substrates was studied by atomic force microscope. The rms surface roughnesses of the films were in the range 0.63-0.65 nm. These ultra smooth nanocrystalline NiO thin films are useful for many applications. High resolution transmission electron microscopic studies revealed that the grains of NiO films on the highly flexible PET substrate were purely crystalline and spherical in shape with diameters 8-10 nm. XRD analysis also supported these results. NiO films grown on the PET substrates were found to have better crystalline quality with fewer defects than those on the glass substrates. The sheet resistances of the NiO films deposited on PET and glass substrates were not much different; having values 5.1 and 5.3 kΩ/□ and decreased to 3.05, 3.1 kΩ/□ respectively with increasing oxygen partial pressure. The thicknesses of the films on both substrates were ∼700 nm. It was also noted that further increase in oxygen partial pressure caused increase in resistivity due to formation of defects in NiO.

The Effect of Oxygen on Bile Resistance in Listeria monocytogenes

Science.gov (United States)

Wright, Morgan L; Pendarvis, Ken; Nanduri, Bindu; Edelmann, Mariola J; Jenkins, Haley N; Reddy, Joseph S; Wilson, Jessica G; Ding, Xuan; Broadway, Paul R; Ammari, Mais G; Paul, Oindrila; Roberts, Brandy; Donaldson, Janet R

2016-01-01

Listeria monocytogenes is a Gram-positive facultative anaerobe that is the causative agent of the disease listeriosis. The infectious ability of this bacterium is dependent upon resistance to stressors encountered within the gastrointestinal tract, including bile. Previous studies have indicated bile salt hydrolase activity increases under anaerobic conditions, suggesting anaerobic conditions influence stress responses. Therefore, the goal of this study was to determine if reduced oxygen availability increased bile resistance of L. monocytogenes. Four strains representing three serovars were evaluated for changes in viability and proteome expression following exposure to bile in aerobic or anaerobic conditions. Viability for F2365 (serovar 4b), EGD-e (serovar 1/2a), and 10403S (serovar 1/2a) increased following exposure to 10% porcine bile under anaerobic conditions (P 0.05) in bile resistance between aerobic and anaerobic conditions, indicating that oxygen availability does not influence resistance in this strain. The proteomic analysis indicated F2365 and EGD-e had an increased expression of proteins associated with cell envelope and membrane bioenergetics under anaerobic conditions, including thioredoxin-disulfide reductase and cell division proteins. Interestingly, HCC23 had an increase in several dehydrogenases following exposure to bile under aerobic conditions, suggesting that the NADH:NAD+ is altered and may impact bile resistance. Variations were observed in the expression of the cell shape proteins between strains, which corresponded to morphological differences observed by scanning electron microscopy. These data indicate that oxygen availability influences bile resistance. Further research is needed to decipher how these changes in metabolism impact pathogenicity in vivo and also the impact that this has on susceptibility of a host to listeriosis. PMID:27274623

Effects of prosthetic foot forefoot flexibility on oxygen cost and subjective preference rankings of unilateral transtibial prosthesis users

OpenAIRE

Mark Edwards, MHPE, CP; Stefania Fatone, PhD; Andrew Hansen, PhD; Elizabeth Klodd, MS

2010-01-01

The investigators conducted a double-blind randomized crossover study to determine the effects of prosthetic foot forefoot flexibility on oxygen cost and subjective preference rankings of 13 unilateral transtibial prosthesis users. Five experimental feet were fabricated for use in the study: F1, F2, F3, F4, and F5. F1 was most flexible, F5 was least flexible, and F3 was designed to conform to a biomimetic ankle-foot roll-over shape. The experimental feet were modeled after the Shape&Roll pros...

Oxygen-deficient hematite nanorods as high-performance and novel negative electrodes for flexible asymmetric supercapacitors.

Science.gov (United States)

Lu, Xihong; Zeng, Yinxiang; Yu, Minghao; Zhai, Teng; Liang, Chaolun; Xie, Shilei; Balogun, Muhammad-Sadeeq; Tong, Yexiang

2014-05-21

Oxygen-deficient α-Fe2 O3 nanorods with outstanding capacitive performance are developed and demonstrated as novel negative electrodes for flexible asymmetric supercapacitors. The asymmetric-supercapacitor device based on the oxygen-deficient α-Fe2 O3 nanorod negative electrode and a MnO2 positive electrode achieves a maximum energy density of 0.41 mW·h/cm(3) ; it is also capable of charging a mobile phone and powering a light-emitting diode indicator. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphene-based inkjet printing of flexible bioelectronic circuits and sensors

Science.gov (United States)

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

2013-03-01

Bioelectronics involves interfacing functional biomolecules or living cells with electronic circuitry. Recent advances in electrically conductive inks and inkjet printing technologies have enabled bioelectronic devices to be fabricated on mechanically flexible polymers, paper and silk. In this research, non-conductive graphene-oxide (GO) inks are synthesized from inexpensive graphite powders. Once printed on the flexible substrate the electrical conductivity of the micro-circuitry can be restored through thermal reduction. Laser irradiation is one method being investigated for transforming the high resistance printed GO film into conductive oxygen reduced graphene-oxide (rGO). Direct laser writing is a precision fabrication process that enables the imprinting of conductive and resistive micro-features on the GO film. The mechanically flexible rGO microcircuits can be further biofunctionalized using molecular self-assembly techniques. Opportunities and challenges in exploiting these emerging technologies for developing biosensors and bioelectronic cicruits are briefly discussed.

Migration of interfacial oxygen ions modulated resistive switching in oxide-based memory devices

Science.gov (United States)

Chen, C.; Gao, S.; Zeng, F.; Tang, G. S.; Li, S. Z.; Song, C.; Fu, H. D.; Pan, F.

2013-07-01

Oxides-based resistive switching memory induced by oxygen ions migration is attractive for future nonvolatile memories. Numerous works had focused their attentions on the sandwiched oxide materials for depressing the characteristic variations, but the comprehensive studies of the dependence of electrodes on the migration behavior of oxygen ions are overshadowed. Here, we investigated the interaction of various metals (Ni, Co, Al, Ti, Zr, and Hf) with oxygen atoms at the metal/Ta2O5 interface under electric stress and explored the effect of top electrode on the characteristic variations of Ta2O5-based memory device. It is demonstrated that chemically inert electrodes (Ni and Co) lead to the scattering switching characteristics and destructive gas bubbles, while the highly chemically active metals (Hf and Zr) formed a thick and dense interfacial intermediate oxide layer at the metal/Ta2O5 interface, which also degraded the resistive switching behavior. The relatively chemically active metals (Al and Ti) can absorb oxygen ions from the Ta2O5 film and avoid forming the problematic interfacial layer, which is benefit to the formation of oxygen vacancies composed conduction filaments in Ta2O5 film thus exhibit the minimum variations of switching characteristics. The clarification of oxygen ions migration behavior at the interface can lead further optimization of resistive switching performance in Ta2O5-based memory device and guide the rule of electrode selection for other oxide-based resistive switching memories.

Resistive switching characteristics of solution-processed organic-inorganic blended films for flexible memory applications

Science.gov (United States)

Baek, Il-Jin; Cho, Won-Ju

2018-02-01

We developed a hybrid organic-inorganic resistive random access memory (ReRAM) device that uses a solution-process to overcome the disadvantages of organic and inorganic materials for flexible memory applications. The drawbacks of organic and inorganic materials are a poor electrical characteristics and a lack of flexibility, respectively. We fabricated a hybrid organic-inorganic switching layer of ReRAM by blending HfOx or AlOx solution with PMMA solution and investigated the resistive switching behaviour in Ti/PMMA/Pt, Ti/PMMA-HfOx/Pt and Ti/PMMA-AlOx/Pt structures. It is found that PMMA-HfOx or PMMA-AlOx hybrid switching layer has a larger memory window, more stable durability and retention characteristics, and a better set/reset voltage distribution than PMMA layer. Further, it is confirmed that the flexibility of the PMMA-HfOx and PMMA-AlOx blended films was almost similar to that of the organic PMMA film. Thus, the solution-processed organic-inorganic blended films are considered a promising material for a non-volatile memory device on a flexible or wearable electronic system.

Hydroxyapatite/poly(epsilon-caprolactone) double coating on magnesium for enhanced corrosion resistance and coating flexibility.

Science.gov (United States)

Jo, Ji-Hoon; Li, Yuanlong; Kim, Sae-Mi; Kim, Hyoun-Ee; Koh, Young-Hag

2013-11-01

Hydroxyapatite was deposited on pure magnesium (Mg) with a flexible poly(ε-caprolactone) interlayer to reduce the corrosion rate of Mg and enhance coating flexibility. The poly(ε-caprolactone) interlayer was uniformly coated on Mg by a spraying method, followed by hydroxyapatite deposition on the poly(ε-caprolactone) using an aerosol deposition method. In scanning electron microscopy observations, inorganic/organic composite-like structure was observed between the hydroxyapatite and poly(ε-caprolactone) layers, resulting from the collisions of hydroxyapatite particles into the poly(ε-caprolactone) matrix at the initial stage of the aerosol deposition. The corrosion resistance of the coated Mg was examined using potentiodynamic polarization tests. The hydroxyapatite/poly(ε-caprolactone) double coating remarkably improved the corrosion resistance of Mg in Hank's solution. In the in vitro cell tests, the coated Mg showed better cell adhesion compared with the bare Mg due to the reduced corrosion rate and enhanced biocompatibility. The stability and flexibility of hydroxyapatite/poly(ε-caprolactone) double coating was investigated by scanning electron microscopy inspections after the coated Mg was deformed. The hydroxyapatite coating on the poly(ε-caprolactone) interlayer revealed enhanced coating stability and flexibility without cracking or delamination during bending and stretching compared with the hydroxyapatite single coating. These results demonstrated that the hydroxyapatite/poly(ε-caprolactone) double coating significantly improved the surface corrosion resistance of Mg and enhanced coating flexibility for use of Mg as a biodegradable implant.

Roll-to-roll printed resistive WORM memory on a flexible substrate

Science.gov (United States)

Leppäniemi, Jaakko; Mattila, Tomi; Kololuoma, Terho; Suhonen, Mika; Alastalo, Ari

2012-08-01

The fabrication process and the operation characteristics of a fully roll-to-roll printed resistive write-once-read-many memory on a flexible substrate are presented. The low-voltage (memories from a high resistivity ‘0’ state to a low resistivity ‘1’ state is based on the rapid electrical sintering of bits containing silver nanoparticles. The bit ink is formulated by mixing two commercially available silver nanoparticle inks in order to tune the initial square resistance of the bits and to create a self-organized network of percolating paths. The electrical performance of the memories, including read and write characteristics, is described and the long-term stability of the less stable ‘0’ state is studied in different environmental conditions. The memories can find use in low-cost mass printing applications.

Roll-to-roll printed resistive WORM memory on a flexible substrate

International Nuclear Information System (INIS)

Leppäniemi, Jaakko; Mattila, Tomi; Suhonen, Mika; Alastalo, Ari; Kololuoma, Terho

2012-01-01

The fabrication process and the operation characteristics of a fully roll-to-roll printed resistive write-once-read-many memory on a flexible substrate are presented. The low-voltage (<10 V) write operation of the memories from a high resistivity ‘0’ state to a low resistivity ‘1’ state is based on the rapid electrical sintering of bits containing silver nanoparticles. The bit ink is formulated by mixing two commercially available silver nanoparticle inks in order to tune the initial square resistance of the bits and to create a self-organized network of percolating paths. The electrical performance of the memories, including read and write characteristics, is described and the long-term stability of the less stable ‘0’ state is studied in different environmental conditions. The memories can find use in low-cost mass printing applications. (paper)

Preparation of flexible and heat-resisting conductive transparent film by the pyrosol process

International Nuclear Information System (INIS)

Usami, Hisanao; Nakasa, Akihiko; Adachi, Mami; Suzuki, Eiji; Fujimatsu, Hitoshi; Ohashi, Tatsuya; Yamada, Shigeo; Tsugita, Kouhei; Taniguchi, Yoshio

2006-01-01

A pyrosol process was successfully applied for the preparation of a flexible, conductive, and transparent inorganic film, a tin-doped indium oxide (ITO) film lined with a thin mica layer. This flexible heat-resistant ITO-mica film exhibited high conductivity and transparency, comparable to ITO deposited on glass substrate. The minimum radius of bending for the film, without any recognizable change in the conductivity and appearance, was 8 mm. The ITO deposited on mica showed a large (222) diffraction peak with a smaller (400) peak, in contrast to ITO deposited with (400) orientation on an ordinary glass substrate. Using the ITO-mica film, a prototype model of a flexible organic light emitting diode was fabricated

Atomic-Oxygen-Durable and Electrically-Conductive CNT-POSS-Polyimide Flexible Films for Space Applications.

Science.gov (United States)

Atar, Nurit; Grossman, Eitan; Gouzman, Irina; Bolker, Asaf; Murray, Vanessa J; Marshall, Brooks C; Qian, Min; Minton, Timothy K; Hanein, Yael

2015-06-10

In low Earth orbit (LEO), hazards such as atomic oxygen (AO) or electrostatic discharge (ESD) degrade polymeric materials, specifically, the extensively used polyimide (PI) Kapton. We prepared PI-based nanocomposite films that show both AO durability and ESD protection by incorporating polyhedral oligomeric silsesquioxane (POSS) and carbon nanotube (CNT) additives. The unique methods that are reported prevent CNT agglomeration and degradation of the CNT properties that are common in dispersion-based processes. The influence of the POSS content on the electrical, mechanical, and thermo-optical properties of the CNT-POSS-PI films was investigated and compared to those of control PI and CNT-PI films. CNT-POSS-PI films with 5 and 15 wt % POSS content exhibited sheet resistivities as low as 200 Ω/□, and these resistivities remained essentially unchanged after exposure to AO with a fluence of ∼2.3 × 10(20) O atoms cm(-2). CNT-POSS-PI films with 15 wt % POSS content exhibited an erosion yield of 4.8 × 10(-25) cm(3) O atom(-1) under 2.3 × 10(20) O atoms cm(-2) AO fluence, roughly one order of magnitude lower than that of pure PI films. The durability of the conductivity of the composite films was demonstrated by rolling film samples with a tight radius up to 300 times. The stability of the films to thermal cycling and ionizing radiation was also demonstrated. These properties make the prepared CNT-POSS-PI films with 15 wt % POSS content excellent candidates for applications where AO durability and electrical conductivity are required for flexible and thermally stable materials. Hence, they are suggested here for LEO applications such as the outer layers of spacecraft thermal blankets.

"Tissue oxygen tension, a determinant of resistance to infection and ...

African Journals Online (AJOL)

"Tissue oxygen tension, a determinant of resistance to infection and healing" - An Inaugural Lecture. K Jönsson. Abstract. An Inaugural Lecture Given in the University of Zimbabwe on 21 June 2001. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

Fabrication of nano-sized metal patterns on flexible polyethylene-terephthalate substrate using bi-layer nanoimprint lithography

Energy Technology Data Exchange (ETDEWEB)

Hwang, Seon Yong; Jung, Ho Yong [Department of Materials Science and Engineering, Korea University, Seoul, 136-701 (Korea, Republic of); Jeong, Jun-Ho [Nano-Mechanical Systems Research Center, Korea Institute of Machinery and Materials, Yuseong-gu Daejeon, 305-343 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.k [Department of Materials Science and Engineering, Korea University, Seoul, 136-701 (Korea, Republic of)

2009-05-29

Polymer films are widely used as a substrate for displays and for solar cells since they are cheap, transparent and flexible, and their material properties are easy to design. Polyethylene-terephthalate (PET) is especially useful for various applications requiring transparency, flexibility and good thermal and chemical resistance. In this study, nano-sized metal patterns were fabricated on flexible PET film by using nanoimprint lithography (NIL). Water-soluble poly-vinyl alcohol (PVA) resin was used as a planarization and sacrificial layer for the lift-off process, as it does not damage the PET films and can easily be etched off by using oxygen plasma. NIL was used to fabricate the nano-sized patterns on the non-planar or flexible substrate. Finally, a nano-sized metal pattern was successfully formed by depositing the metal layer over the imprinted resist patterns and applying the lift-off process, which is economic and environmentally friendly, to the PET films.

Layout designs of surface barrier coatings for boosting the capability of oxygen/vapor obstruction utilized in flexible electronics

Science.gov (United States)

Lee, Chang-Chun; Huang, Pei-Chen; He, Jing-Yan

2018-04-01

Organic light-emitting diode-based flexible and rollable displays have become a promising candidate for next-generation flexible electronics. For this reason, the design of surface multi-layered barriers should be optimized to enhance the long-term mechanical reliability of a flexible encapsulation that prevents the penetration of oxygen and vapor. In this study, finite element-based stress simulation was proposed to estimate the mechanical reliability of gas/vapor barrier design with low-k/silicon nitride (low-k/SiNx) stacking architecture. Consequently, stress-induced failure of critical thin films within the flexible display under various bending conditions must be considered. The feasibility of one pair SiO2/SiNx barrier design, which overcomes the complex lamination process, and the critical bending radius, which is decreased to 1.22 mm, were also examined. In addition, the influence of distance between neutral axes to the concerned layer surface dominated the induced-stress magnitude rather than the stress compliant mechanism provided from stacked low-k films.

UV Enhanced Oxygen Response Resistance Ratio of ZnO Prepared by Thermally Oxidized Zn on Sapphire Substrate

Directory of Open Access Journals (Sweden)

Cheng-Chang Yu

2013-01-01

Full Text Available ZnO thin film was fabricated by thermally oxidized Zn at 600°C for 1 h. A surface containing nanostructured dumbbell and lines was observed by scanning electron microscope (SEM. The ZnO resistor device was formed after the following Ti/Au metallization. The device resistance was characterized at different oxygen pressure environment in the dark and under ultraviolet (UV light illumination coming from the mercury lamp with a short pass filter. The resistance increases with the increase of oxygen pressure. The resistance decreases and response increases with the increase of light intensity. Models considering the barrier height variation caused by the adsorbed oxygen related species were used to explain these results. The UV light illumination technology shows an effective method to enhance the detection response for this ZnO resistor oxygen sensor.

Flexible Sheet-Type Sensor for Noninvasive Measurement of Cellular Oxygen Metabolism on a Culture Dish.

Directory of Open Access Journals (Sweden)

Mari Kojima

Full Text Available A novel flexible sensor was developed for the noninvasive oxygen metabolism measurement of cultivated cells and tissues. This device is composed of a transparent double-layered polymer sheet of ethylene-vinyl alcohol (EVOH and poly(dimethylsiloxane (PDMS having an array of microhole structures of 90 μm diameter and 50 μm depth on its surface. All the microhole structures were equipped with a 1-μm-thick optical chemical sensing layer of platinum porphyrin-fluoropolymer on their bottom. The three-dimensional microstructures of the sensor were fabricated by a newly developed simple and low-cost production method named self-aligned hot embossing. The device was designed to be attached slightly above the cells cultivated on a dish to form a temporarily closed microspace over the target cells during measurement. Since the change in oxygen concentration is relatively fast in the microcompartmentalized culture medium, a rapid evaluation of the oxygen consumption rate is possible by measuring the phosphorescence lifetime of the platinum porphyrin-fluoropolymer. The combined use of the device and an automated optical measurement system enabled the high-throughput sensing of cellular oxygen consumption (100 points/min. We monitored the oxygen metabolism of the human breast cancer cell line MCF7 on a Petri dish and evaluated the oxygen consumption rate to be 0.72 ± 0.12 fmol/min/cell. Furthermore, to demonstrate the utility of the developed sensing system, we demonstrated the mapping of the oxygen consumption rate of rat brain slices and succeeded in visualizing a clear difference among the layer structures of the hippocampus, i.e., the cornu ammonis (CA1 and CA3 and dentate gyrus (DG.

Leaching-resistant carrageenan-based colorimetric oxygen indicator films for intelligent food packaging.

Science.gov (United States)

Vu, Chau Hai Thai; Won, Keehoon

2014-07-23

Visual oxygen indicators can give information on the quality and safety of packaged food in an economic and simple manner by changing color based on the amount of oxygen in the packaging, which is related to food spoilage. In particular, ultraviolet (UV)-activated oxygen indicators have the advantages of in-pack activation and irreversibility; however, these dye-based oxygen indicator films suffer from dye leaching upon contact with water. In this work, we introduce carrageenans, which are natural sulfated polysaccharides, to develop UV-activated colorimetric oxygen indicator films that are resistant to dye leakage. Carrageenan-based indicator films were fabricated using redox dyes [methylene blue (MB), azure A, and thionine], a sacrificial electron donor (glycerol), an UV-absorbing photocatalyst (TiO2), and an encapsulation polymer (carrageenan). They showed even lower dye leakage in water than conventional oxygen indicator films, owing to the electrostatic interaction of anionic carrageenan with cationic dyes. The MB/TiO2/glycerol/carrageenan oxygen indicator film was successfully bleached upon UV irradiation, and it regained color very rapidly in the presence of oxygen compared to the other waterproof oxygen indicator films.

Microstructure evolution characteristics induced by oxygen vacancy generation in anatase TiO2 based resistive switching devices

Science.gov (United States)

Liu, Chen; Gao, Bin; Huang, Peng; Kang, Jinfeng

2017-03-01

In this work, first principle calculations are employed to study the microstructure characteristics of the anatase TiO2 resistive switching material associated with the generation of oxygen vacancy (V o) based nanofilaments during the switching process. The calculations indicate that both the magnéli phase Ti4O7 and V o-defect phase of anatase TiO2 may be formed with the generation of oxygen vacancies during the forming and SET processes. Based on the calculations, a new physical insight is proposed to clarify the microstructure evolution characteristics of the anatase TiO2 resistive switching material and the correlation with resistive switching behaviors. During the forming or SET process, the anatase TiO2 is first excited to a transition state with the generation of oxygen vacancies, then fully relaxes to a stable V o-defect state. This V o-defect state may either recover to the original state with the recombination of the oxygen vacancies, which causes the reversible resistive switching behavior, or further transform to a much more stable state—the magnéli phase Ti4O7, through a phase transition process with the generation of many more oxygen vacancies. The phase transition from V o- defective anatase phase to magnéli phase Ti4O7 causes the failure of the resistive switching due to the significantly reduced possibility of the reversible phase transition from the magnéli phase to the anatase phase, compared with the possibility of the recombination from the V o-defective anatase.

Free-standing, flexible β-Ni(OH)2/electrochemically-exfoliated graphene film electrode for efficient oxygen evolution

Science.gov (United States)

Wang, Lanlan; Zhang, Jian; Jiang, Weitao; Zhao, Hong; Liu, Hongzhong

2018-03-01

The oxidation of water into molecular oxygen (oxygen evolution reaction, OER) is a pivotal reaction in many energy conversion devices. The high cost of IrO2, however, seriously hinder its large-scale applications in water oxidation. Here, we have at first reported a free-standing and flexible film electrode consisting of 2D β-Ni(OH)2/electrochemically-exfoliated graphene hybrid nanosheets (NiG-2), which is synthesized by a solvothermal reaction and an assembly process. The as-obtained NiG-2 film electrode exhibited an excellent electrocatalytic OER activity with an extremely low OER onset overpotential of ∼250 mV in a 1 M KOH aqueous solution, which is lower than these of the commercial Ir/C (370 mV at 10 mA cm-2) catalyst.

Influence of preadsorbed oxygen on the sign and magnitude of the chemisorption-induced resistance change for H2 adsorption onto Fe films

Science.gov (United States)

Shanabarger, M. R.

1986-01-01

Measurements have been made of the chemisorption-induced resistance change for H2 adsorbed onto Fe film substrates predosed with fixed coverages of chemisorbed oxygen. The measurements were made at temperatures from 295 to 340 K and for estimated oxygen coverages of less than 0.1 monolayers. Two distinct resistance change components were observed in both the adsorption kinetics and the equilibrium isotherms: a positive component which is associated with the adsorption of H2 onto a clean Fe surface, and a negative component which was correlated with the presence of the chemisorbed oxygen. The resistance change isotherms can be fit with a model which assumes that each of the resistance change components result from dissociative chemisorbed hydrogen. Possible mechanisms for the chemisorbed-oxygen-induced negative resistance change are discussed.

Towards forming-free resistive switching in oxygen engineered HfO{sub 2−x}

Energy Technology Data Exchange (ETDEWEB)

Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P.; Zaumseil, P.; Sowinska, M.; Walczyk, D. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Gloskovskii, A. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-02-10

We have investigated the resistive switching behavior in stoichiometric HfO{sub 2} and oxygen-deficient HfO{sub 2−x} thin films grown on TiN electrodes using reactive molecular beam epitaxy. Oxygen defect states were controlled by the flow of oxygen radicals during thin film growth. Hard X-ray photoelectron spectroscopy confirmed the presence of sub-stoichiometric hafnium oxide and defect states near the Fermi level. The oxygen deficient HfO{sub 2−x} thin films show bipolar switching with an electroforming occurring at low voltages and low operating currents, paving the way for almost forming-free devices for low-power applications.

Effects of Thermal Resistance on One-Dimensional Thermal Analysis of the Epidermal Flexible Electronic Devices Integrated with Human Skin

Science.gov (United States)

Li, He; Cui, Yun

2017-12-01

Nowadays, flexible electronic devices are increasingly used in direct contact with human skin to monitor the real-time health of human body. Based on the Fourier heat conduction equation and Pennes bio-heat transfer equation, this paper deduces the analytical solutions of one - dimensional heat transfer for flexible electronic devices integrated with human skin under the condition of a constant power. The influence of contact thermal resistance between devices and skin is considered as well. The corresponding finite element model is established to verify the correctness of analytical solutions. The results show that the finite element analysis agrees well with the analytical solution. With bigger thermal resistance, temperature increase of skin surface will decrease. This result can provide guidance for the design of flexible electronic devices to reduce the negative impact that exceeding temperature leave on human skin.

A flexible well-mixed milliliter-scale reactor with high oxygen transfer rate for microbial cultivations

DEFF Research Database (Denmark)

Bolic, Andrijana; Larsson, Hilde Kristina; Hugelier, Siewert

2016-01-01

solution and replacement for existing microtiter plates, shaken flasks and bench scale bioreactors. In this work, a new design of a milliliter-scale bioreactor system is presented and characterized. The entire system consists of a platform with gas connections, heater, temperature sensor and optical fibers...... on the one side and a bioreactor with special designed magnetic stirrer and non-invasive optical sensors for measurement of pH, dissolved oxygen and optical density on the other side. The system has a high level of flexibility in terms of volume (0.5–2 mL), aeration (sparging and surface aeration) and mixing...

Oxygen plasma effects on zero resistance behavior of Yb,Er-doped YBCO (123) based superconductors

Energy Technology Data Exchange (ETDEWEB)

Schaefer, Helmut; Rathmann, Dirk [Department of Physics, Biophysics, and Photosynthesis, Freie Universitaet Berlin (Germany); Banko, Franziska; Steinhart, Martin [Physical Chemistry, Institute of Chemistry of New Materials, University of Osnabrueck (Germany); Nordmann, Joerg; Voss, Benjamin [Inorganic Chemistry, Institute of Chemistry of New Materials, University of Osnabrueck (Germany); Walder, Lorenz [Organic Chemistry, Molecular Electrochemistry, Institute of Chemistry of New Materials, University of Osnabrueck (Germany)

2014-08-15

Rare-earth doped YBa{sub 2}Cu{sub 3}O{sub 7-δ} samples were synthesized starting from the corresponding oxides Y{sub 2}O{sub 3}, Yb{sub 2}O{sub 3}, Er{sub 2}O{sub 3}, CuO as well as Ba(OH){sub 2} by heating to 950 C under air. The doping concentrations were adjusted to 15 % Yb, 7 % Er and 20 % Yb, 15 % Er, respectively, with respect to the yttrium content. The orthogonal phased (123) YBCO ceramics were exposed to an oxygen plasma for 140 and 380 min. Zero resistance temperature (T{sub c,0}) was determined by measuring the resistivity-temperature dependence using a classical four point measurement approach. Under optimal conditions with respect to the material composition and the oxygen treatment an unusual high zero resistance temperature of 97.5 K (T{sub c,onset} ∼ 101 K) was achieved. This represents an increase of T{sub c,0} by 7.5 K. The oxygen treatment could not be monitored by IR spectroscopy, X-ray fluorescence spectroscopy, and X-ray powder diffraction. The results showed good reproducibility. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Solid-state Memory on Flexible Silicon for Future Electronic Applications

KAUST Repository

Ghoneim, Mohamed

2016-11-01

Advancements in electronics research triggered a vision of a more connected world, touching new unprecedented fields to improve the quality of our lives. This vision has been fueled by electronic giants showcasing flexible displays for the first time in consumer electronics symposiums. Since then, the scientific and research communities partook on exploring possibilities for making flexible electronics. Decades of research have revealed many routes to flexible electronics, lots of opportunities and challenges. In this work, we focus on our contributions towards realizing a complimentary approach to flexible inorganic high performance electronic memories on silicon. This approach provides a straight forward method for capitalizing on the existing well-established semiconductor infrastructure, standard processes and procedures, and collective knowledge. Ultimately, we focus on understanding the reliability and functionality anomalies in flexible electronics and flexible solid state memory built using the flexible silicon platform. The results of the presented studies show that: (i) flexible devices fabricated using etch-protect-release approach (with trenches included in the active area) exhibit ~19% lower safe operating voltage compared to their bulk counterparts, (ii) they can withstand prolonged bending duration (static stress) but are prone to failure under dynamic stress as in repeated bending and re-flattening, (iii) flexible 3D FinFETs exhibit ~10% variation in key properties when exposed to out-of-plane bending stress and out-of-plane stress does not resemble the well-studied in-plane stress used in strain engineering, (iv) resistive memories can be achieved on flexible silicon and their basic resistive property is preserved but other memory functionalities (retention, endurance, speed, memory window) requires further investigations, (v) flexible silicon based PZT ferroelectric capacitors exhibit record polarization, capacitance, and endurance (1 billion

The Experimental Measurement of Local and Bulk Oxygen Transport Resistances in the Catalyst Layer of Proton Exchange Membrane Fuel Cells.

Science.gov (United States)

Wang, Chao; Cheng, Xiaojing; Lu, Jiabin; Shen, Shuiyun; Yan, Xiaohui; Yin, Jiewei; Wei, Guanghua; Zhang, Junliang

2017-12-07

Remarkable progress has been made in reducing the cathodic Pt loading of PEMFCs; however, a huge performance loss appears at high current densities, indicating the existence of a large oxygen transport resistance associated with the ultralow Pt loading catalyst layer. To reduce the Pt loading without sacrificing cell performance, it is essential to illuminate the oxygen transport mechanism in the catalyst layer. Toward this goal, an experimental approach to measure the oxygen transport resistance in catalyst layers is proposed and realized for the first time in this study. The measuring approach involves a dual-layer catalyst layer design, which consists of a dummy catalyst layer and a practical catalyst layer, followed by changing the thickness of dummy layer to respectively quantify the local and bulk resistances via limiting current measurements combined with linear extrapolation. The experimental results clearly reveal that the local resistance dominates the total resistance in the catalyst layer.

All ITO-based transparent resistive switching random access memory using oxygen doping method

International Nuclear Information System (INIS)

Kim, Hee-Dong; Yun, Min Ju; Kim, Sungho

2015-01-01

Recently, transparent memory would be useful in invisible electronics. In this work, for the first time we present a feasibility of stable unipolar resistive switching (RS) characteristics with reset current of sub-micron ampere for the fully transparent ITO/oxygen-doped ITO/ITO memory capacitors, i.e., all ITO structures, produced by sputtering method, which shows a high optical transmittance of approximately 80% in the visible region as well as near ultra-violet region. In addition, in a RS test to evaluate a reliability for the proposed memory devices, we observed a stable endurance of >100 cycles and a retention time of >10 4  s at 85 °C, with a current ratio of ∼10 2 to ∼10 3 . This result indicates that this transparent memory by engineering the amount of oxygen ions within the ITO films could be a milestone for future see-through electronic devices. - Highlights: • The resistive switching characteristics of the transparent ITO/O-doped ITO/ITO RRAM cells have investigated. • All ITO-based RRAM cell is achieved using oxygen doping method. • Good endurance and long retention time were observed.

Preparation of high-content hexagonal boron nitride composite film and characterization of atomic oxygen erosion resistance

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu; Li, Min; Gu, Yizhuo; Wang, Shaokai, E-mail: wsk@buaa.edu.cn; Zhang, Zuoguang

2017-04-30

Highlights: • Hexagonal boron nitride nanosheets can be well exfoliated with the help of nanofibrillated cellulose. • A carpet-like rough surface and distortion in crystal structure of h-BN are found in both h-BN film and h-BN/epoxy film after AO exposure. • H-BN/epoxy film exhibits a higher mass loss and erosion yield, different element content changes and chemical oxidations compared with h-BN film. - Abstract: Space aircrafts circling in low earth orbit are suffered from highly reactive atomic oxygen (AO). To shield AO, a flexible thin film with 80 wt.% hexagonal boron nitride (h-BN) and h-BN/epoxy film were fabricated through vacuum filtration and adding nanofibrillated cellulose fibers. H-BN nanosheets were hydroxylated for enhancing interaction in the films. Mass loss and erosion yield at accumulated AO fluence about 3.04 × 10{sup 20} atoms/cm{sup 2} were adopted to evaluate the AO resistance properties of the films. A carpet-like rough surface, chemical oxidations and change in crystal structure of h-BN were found after AO treatment, and the degrading mechanism was proposed. The mass loss and erosion yield under AO attack were compared between h-BN film and h-BN/epoxy film, and the comparison was also done for various types of shielding AO materials. Excellent AO resistance property of h-BN film is shown, and the reasons are analyzed.

The electrochemical behavior of cobalt phthalocyanine/platinum as methanol-resistant oxygen-reduction electrocatalysts for DMFC

Energy Technology Data Exchange (ETDEWEB)

Lu, Yuhao; Reddy, Ramana G. [Department of Metallurgical and Materials Engineering, The University of Alabama, P.O. Box 870202, Tuscaloosa, AL 35487 (United States)

2007-02-01

The electrochemical behavior of cobalt phthalocyanine/platinum as methanol-resistant oxygen-reduction electrocatalyst for DMFC was investigated. Platinum was chemically deposited on the carbon-supported cobalt phthalocyanine (CoPc), and then it was heat-treated in high purity nitrogen at 300 C, 635 C and 980 C. In order to evaluate the electrocatalytic behavior of CoPc-Pt/C, the PtCo/C and Pt/C as reference catalysts were employed. TGA, XRD, EDAX, XPS and electrochemical experiments were used to study the thermal stability, crystal structure, physical characterization and electrochemical behavior of these catalysts. These catalysts exhibited similar electrocatalytic activity for oxygen reaction in 0.5 M H{sub 2}SO{sub 4} solution. In methanol tolerance experiments, Pt/C, PtCo/C and CoPc-Pt/C heated at 980 C were active for the methanol oxidation reaction (MOR). The presence of Co did not improve resistance to methanol poisoning. However, the CoPc-Pt/C after 300 C or 635 C heat-treatment demonstrated significant inactivity for MOR, hence they have a good ability to resist methanol poisoning. The current study indicated that the macrocyclic structure of phthalocyanine is the most important factor to improve the methanol tolerance of CoPc-Pt/C as the oxygen-reduction reaction (ORR) electrocatalyst. The CoPc-Pt based catalyst should be a good alternation for oxygen electro-reduction reaction in DMFC. (author)

Investigations on the mechanism of oxygen-dependent plant processes: ethylene biosynthesis and cyanide-resistant respiration

International Nuclear Information System (INIS)

Stegink, S.J.

1985-01-01

Two oxygen-dependent plant processes were investigated. A cell-free preparation from pea (Pisum sativum L., cv. Alaska) was used to study ethylene biosynthesis from 1-aminocyclopropane-1-carboxylic acid. Mitochondrial cyanide-resistant respiration was investigated in studies with 14 C-butyl gallate and other respiratory effectors. Ethylene biosynthesis was not due to a specific enzyme, or oxygen radicals. Rather, hydrogen peroxide, generated at low levels, coupled with endogenous manganese produced ethylene. 14 C-butyl gallate bound specifically to mitochondria from cyanide-sensitive and -resistant higher plants and Neurospora crassa mitochondria. The amount of gallate bound was similar for all higher plant mitochondria. Rat liver mitochondria bound very little 14 C-butyl gallate. Plant mitochondria in which cyanide-resistance was induced bound as much 14 C-butyl gallate as before induction. However mitochondria from recently harvested white potato tubers did not bind the gallate. The observations suggest that an engaging factor couples with a gallate binding site in the mitochondrial membrane. With skunk cabbage spadix mitochondria the I 5 0 for antimycin A inhibition of oxygen uptake was decreased by salicylhydroxamic acid pretreatment; this was also true for reverse order additions. No shift was observed with mung bean hypocotyl or Jerusalem artichoke tuber mitochondria

Oxygen-ion-migration-modulated bipolar resistive switching and complementary resistive switching in tungsten/indium tin oxide/gold memory device

Science.gov (United States)

Wu, Xinghui; Zhang, Qiuhui; Cui, Nana; Xu, Weiwei; Wang, Kefu; Jiang, Wei; Xu, Qixing

2018-06-01

In this paper, we report our investigation of room-temperature-fabricated tungsten/indium tin oxide/gold (W/ITO/Au) resistive random access memory (RRAM), which exhibits asymmetric bipolar resistive switching (BRS) behavior. The device displays good write/erase endurance and data retention properties. The device shows complementary resistive switching (CRS) characteristics after controlling the compliance current. A WO x layer electrically formed at the W/ITO in the forming process. Mobile oxygen ions within ITO migrate toward the electrode/ITO interface and produce a semiconductor-like layer that acts as a free-carrier barrier. The CRS characteristic here can be elucidated in light of the evolution of an asymmetric free-carrier blocking layer at the electrode/ITO interface.

Nanotwin-enhanced fatigue resistance of ultrathin Ag films for flexible electronics applications

Energy Technology Data Exchange (ETDEWEB)

Wan, H.Y. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016 (China); Luo, X.M.; Li, X.; Liu, W. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, G.P., E-mail: gpzhang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2016-10-31

Fatigue strength and cracking behavior of ultrathin Ag films on flexible polyimide substrates were investigated. The experimental results show that the enhanced fatigue strength of the 50 nm-thick Ag films not only is caused by the increase in the yield stress and the suppression of cyclic strain localization, but also results from the severe crack deflection induced by the formation of nanotwins, which delays the fatigue crack initiation and enhances the resistance to the fatigue crack growth. The fatigue cracking mechanism for the nanocrystalline metal films is evaluated.

Improved surface corrosion resistance of WE43 magnesium alloy by dual titanium and oxygen ion implantation

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ying [Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wu, Guosong; Lu, Qiuyuan [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wu, Jun [Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong (China); Xu, Ruizhen [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Yeung, Kelvin W.K., E-mail: wkkyeung@hku.hk [Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong (China); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2013-02-01

Magnesium alloys are potential biodegradable materials and have attracted much attention due to their outstanding biological performance and mechanical properties. However, their rapid degradation inside the human body cannot meet clinical needs. In order to improve the corrosion resistance, dual titanium and oxygen ion implantation is performed to modify the surface of the WE43 magnesium alloy. X-ray photoelectron spectroscopy is used to characterize the microstructures in the near surface layer and electrochemical impedance spectroscopy, potentiodynamic polarization, and immersion tests are employed to investigate the corrosion resistance of the implanted alloys in simulated body fluids. The results indicate that dual titanium and oxygen ion implantation produces a TiO{sub 2}-containing surface film which significantly enhances the corrosion resistance of WE43 magnesium alloy. Our data suggest a simple and practical means to improve the corrosion resistance of degradable magnesium alloys. - Highlights: ► Surface modification of WE43 magnesium alloy using dual ion implantation ► Dual Ti and O ion implantation produces a homogeneous TiO{sub 2}-containing surface film ► Significant improvement of the alloy corrosion resistance after the dual ion implantation.

Self-Positioned Nanosized Mask for Transparent and Flexible Ferroelectric Polymer Nanodiodes Array.

Science.gov (United States)

Hyun, Seung; Kwon, Owoong; Choi, Chungryong; Vincent Joseph, Kanniyambatti L; Kim, Yunseok; Kim, Jin Kon

2016-10-12

High density arrays of ferroelectric polymer nanodiodes have gained strong attention for next-generation transparent and flexible nonvolatile resistive memory. Here, we introduce a facile and innovative method to fabricate ferroelectric polymer nanodiode array on an ITO-coated poly(ethylene terephthalate) (PET) substrate by using block copolymer self-assembly and oxygen plasma etching. First, polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) micelles were spin-coated on poly(vinylidene fluoride-ran-trifluoroethylene) copolymer (P(VDF-TrFE)) film/ITO-coated PET substrate. After the sample was immersed in a gold precursor (HAuCl 4 ) containing solution, which strongly coordinates with nitrogen group in P2VP, oxygen plasma etching was performed. During the plasma etching, coordinated gold precursors became gold nanoparticles (GNPs), which successfully acted as self-positioned etching mask to fabricate a high density array of P(VDF-TrFE)) nanoislands with GNP at the top. Each nanoisland shows clearly individual diode property, as confirmed by current-voltage (I-V) curve. Furthermore, due to the transparent and flexible nature of P(VDF-TrFE)) nanoisland as well as the substrate, the P(VDF-TrFE) nanodiode array was highly tranparent, and the diode property was maintained even after a large number of bendings (for instance, 1000 times). The array could be used as the next-generation tranparent and flexible nonvolatile memory device.

Fanconi anemia links reactive oxygen species to insulin resistance and obesity.

Science.gov (United States)

Li, Jie; Sipple, Jared; Maynard, Suzette; Mehta, Parinda A; Rose, Susan R; Davies, Stella M; Pang, Qishen

2012-10-15

Insulin resistance is a hallmark of obesity and type 2 diabetes. Reactive oxygen species (ROS) have been proposed to play a causal role in insulin resistance. However, evidence linking ROS to insulin resistance in disease settings has been scant. Since both oxidative stress and diabetes have been observed in patients with the Fanconi anemia (FA), we sought to investigate the link between ROS and insulin resistance in this unique disease model. Mice deficient for the Fanconi anemia complementation group A (Fanca) or Fanconi anemia complementation group C (Fancc) gene seem to be diabetes-prone, as manifested by significant hyperglycemia and hyperinsulinemia, and rapid weight gain when fed with a high-fat diet. These phenotypic features of insulin resistance are characterized by two critical events in insulin signaling: a reduction in tyrosine phosphorylation of the insulin receptor (IR) and an increase in inhibitory serine phosphorylation of the IR substrate-1 in the liver, muscle, and fat tissues from the insulin-challenged FA mice. High levels of ROS, spontaneously accumulated or generated by tumor necrosis factor alpha in these insulin-sensitive tissues of FA mice, were shown to underlie the FA insulin resistance. Treatment of FA mice with the natural anti-oxidant Quercetin restores IR signaling and ameliorates the diabetes- and obesity-prone phenotypes. Finally, pairwise screen identifies protein-tyrosine phosphatase (PTP)-α and stress kinase double-stranded RNA-dependent protein kinase (PKR) that mediate the ROS effect on FA insulin resistance. These findings establish a pathogenic and mechanistic link between ROS and insulin resistance in a unique human disease setting. ROS accumulation contributes to the insulin resistance in FA deficiency by targeting both PTP-α and PKR.

Enhanced oxygen vacancy diffusion in Ta2O5 resistive memory devices due to infinitely adaptive crystal structure

Science.gov (United States)

Jiang, Hao; Stewart, Derek A.

2016-04-01

Metal oxide resistive memory devices based on Ta2O5 have demonstrated high switching speed, long endurance, and low set voltage. However, the physical origin of this improved performance is still unclear. Ta2O5 is an important archetype of a class of materials that possess an adaptive crystal structure that can respond easily to the presence of defects. Using first principles nudged elastic band calculations, we show that this adaptive crystal structure leads to low energy barriers for in-plane diffusion of oxygen vacancies in λ phase Ta2O5. Identified diffusion paths are associated with collective motion of neighboring atoms. The overall vacancy diffusion is anisotropic with higher diffusion barriers found for oxygen vacancy movement between Ta-O planes. Coupled with the fact that oxygen vacancy formation energy in Ta2O5 is relatively small, our calculated low diffusion barriers can help explain the low set voltage in Ta2O5 based resistive memory devices. Our work shows that other oxides with adaptive crystal structures could serve as potential candidates for resistive random access memory devices. We also discuss some general characteristics for ideal resistive RAM oxides that could be used in future computational material searches.

Flexible packaging for PV modules

Science.gov (United States)

Dhere, Neelkanth G.

2008-08-01

Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

Effects of oxygen plasma treatment power on Aramid fiber III/BMI composite humidity resistance properties

Science.gov (United States)

Wang, Jing; Shi, Chen; Feng, Jiayue; Long, Xi; Meng, Lingzhi; Ren, Hang

2018-01-01

The effects of oxygen plasma treatment power on Aramid Fiber III chemical structure and its reinforced bismaleimides (BMI) composite humidity resistance properties were investigated in this work. The aramid fiber III chemical structure under different plasma treatment power were measured by FTIR. The composite bending strength and interlinear shear strength with different plasma treatment power before and after absorption water were tested respectively. The composite rupture morphology was observed by SEM. The FTIR results showed that oxygen plasma treatment do not change the fiber bulk chemical structure. The composite humidity resistance of bending strength and interlinear shear strength are similar for untreated and plasma treated samples. The retention rate of composite bending strength and interlinear shear strength are about 75% and 94%, respectively. The composite rupture mode turns to be the fiber failure after water absorption.

Dual-functional Memory and Threshold Resistive Switching Based on the Push-Pull Mechanism of Oxygen Ions

KAUST Repository

Huang, Yi-Jen

2016-04-07

The combination of nonvolatile memory switching and volatile threshold switching functions of transition metal oxides in crossbar memory arrays is of great potential for replacing charge-based flash memory in very-large-scale integration. Here, we show that the resistive switching material structure, (amorphous TiOx)/(Ag nanoparticles)/(polycrystalline TiOx), fabricated on the textured-FTO substrate with ITO as the top electrode exhibits both the memory switching and threshold switching functions. When the device is used for resistive switching, it is forming-free for resistive memory applications with low operation voltage (<±1 V) and self-compliance to current up to 50 μA. When it is used for threshold switching, the low threshold current is beneficial for improving the device selectivity. The variation of oxygen distribution measured by energy dispersive X-ray spectroscopy and scanning transmission electron microscopy indicates the formation or rupture of conducting filaments in the device at different resistance states. It is therefore suggested that the push and pull actions of oxygen ions in the amorphous TiOx and polycrystalline TiOx films during the voltage sweep account for the memory switching and threshold switching properties in the device.

Unsedated Flexible Upper Gastrointestinal Endoscopy: Need for ...

African Journals Online (AJOL)

Background: To determine the incidence of oxygen desaturation and whether routine oxygen monitoring is necessary during unsedated diagnostic flexible upper gastrointestinal endoscopy. Methods: A prospective study involving 54 consecutive in and out patients who had diagnostic upper gastrointestinal endoscopy at ...

Oxygen radical detoxification enzymes in doxorubicin-sensitive and -resistant P388 murine leukemia cells

International Nuclear Information System (INIS)

Ramu, A.; Cohen, L.; Glaubiger, D.

1984-01-01

One of the proposed mechanisms for the cytotoxic effects of anthracycline compounds suggests that the effect is mediated through the formation of intracellular superoxide radicals. It is therefore possible that doxorubicin resistance is associated with increased intracellular enzyme capacity to convert these superoxide radicals to inactive metabolites. We have measured the relative activities of superoxide dismutase, glutathione peroxidase, and catalase in P388 mouse leukemia cells and in a doxorubicin-resistant subline. Since oxygen-reactive metabolites also play a role in mediating the cytotoxicity of ionizing radiation, the radiosensitivity of both cell lines was also studied. No significant differences in superoxide dismutase activity between these cell lines was observed, indicating that they have a similar capacity to convert superoxide anion radicals to hydrogen peroxide. P388 cells that are resistant to doxorubicin have 1.5 times the glutathione content and 1.5 times the activity of glutathione peroxidase measured in drug-sensitive P388 cells. However, incubation with 1-chloro-2,4-dinitrobenzene, which covalently binds glutathione, had no effect on the sensitivity of either cell line to doxorubicin. Measured catalase activity in drug-resistant P388 cells was one-third of the activity measured in doxorubicin-sensitive P388 cells. The activity of this enzyme was much higher than that of glutathione peroxidase in terms of H 2 O 2 deactivation in both cell lines. It is therefore unlikely that doxorubicin-resistant P388 cells have an increased ability to detoxify reactive oxygen metabolites when compared to drug-sensitive cells. Doxorubicin-resistant P388 cells were significantly more sensitive to X-irradiation than were drug-sensitive P388 cells. These observations suggest that the difference in catalase activity in these cell lines may be associated with the observed differences in radiosensitivity

High-Quality AZO/Au/AZO Sandwich Film with Ultralow Optical Loss and Resistivity for Transparent Flexible Electrodes.

Science.gov (United States)

Zhou, Hua; Xie, Jing; Mai, Manfang; Wang, Jing; Shen, Xiangqian; Wang, Shuying; Zhang, Lihua; Kisslinger, Kim; Wang, Hui-Qiong; Zhang, Jinxing; Li, Yu; Deng, Junhong; Ke, Shanming; Zeng, Xierong

2018-05-09

Transparent flexible electrodes are in ever-growing demand for modern stretchable optoelectronic devices, such as display technologies, solar cells, and smart windows. Such sandwich-film-electrodes deposited on polymer substrates are unattainable because of the low quality of the films, inducing a relatively large optical loss and resistivity as well as a difficulty in elucidating the interference behavior of light. In this article, we report a high-quality AZO/Au/AZO sandwich film with excellent optoelectronic performance, e.g., an average transmittance of about 81.7% (including the substrate contribution) over the visible range, a sheet resistance of 5 Ω/sq, and a figure-of-merit (FoM) factor of ∼55.1. These values are well ahead of those previously reported for sandwich-film-electrodes. Additionally, the interference behaviors of light modulated by the coat and metal layers have been explored with the employment of transmittance spectra and numerical simulations. In particular, a heater device based on an AZO/Au/AZO sandwich film exhibits high performance such as short response time (∼5 s) and uniform temperature field. This work provides a deep insight into the improvement of the film quality of the sandwich electrodes and the design of high-performance transparent flexible devices by the application of a flexible substrate with an atomically smooth surface.

Copper thin film for RFID UHF antenna on flexible substrate

International Nuclear Information System (INIS)

Tran, Nhan Ai; Tran, Huy Nam; Dang, Mau Chien; Fribourg-Blanc, Eric

2010-01-01

A process flow using photolithography and sputtering was studied for copper antenna fabrication on thin poly(ethylene terephthalate) (PET) substrate. The lift-off route was chosen for its flexibility at laboratory scale. It was clarified that the cleaning of PET is an important step that necessitates mild oxygen plasma etching. Then copper is sputter deposited after photolithographic definition of the antenna. Care is necessary since PET, as a very flexible substrate, is temperature sensitive. The temperature increase generated by the impact of deposited copper should be maintained below the glass transition temperature of the polymer to avoid detrimental deformation. dc power of 40 to 50 W was found to be the maximum possible sputtering power for commercial PET. It was found that the resistivity of the thin film is below two times the bulk resistivity of copper for a deposition pressure below 4×10 −3  mbar and thickness above 450 nm. These results enable the reliable fabrication of copper RFID UHF antennae on a PET substrate for further testing of new tag designs. The present paper summarizes the effort to test new designs of antennae for RadioFrequency IDentification (RFID) Ultra High Frequency (UHF) tags, for use in various applications (e.g. object tracking and environment monitoring) in Vietnam

Staphyloxanthin photobleaching sensitizes methicillin-resistant Staphylococcus aureus to reactive oxygen species attack

Science.gov (United States)

Dong, Pu-Ting; Mohammad, Haroon; Hui, Jie; Wang, Xiaoyu; Li, Junjie; Liang, Lijia; Seleem, Mohamed N.; Cheng, Ji-Xin

2018-02-01

Given that the dearth of new antibiotic development loads an existential burden on successful infectious disease therapy, health organizations are calling for alternative approaches to combat methicillin-resistant Staphylococcus aureus (MRSA) infections. Here, we report a drug-free photonic approach to eliminate MRSA through photobleaching of staphyloxanthin, an indispensable membrane-bound antioxidant of S. aureus. The photobleaching process, uncovered through a transient absorption imaging study and quantitated by absorption spectroscopy and mass spectrometry, decomposes staphyloxanthin, and sensitizes MRSA to reactive oxygen species attack. Consequently, staphyloxanthin bleaching by low-level blue light eradicates MRSA synergistically with external or internal reactive oxygen species. The effectiveness of this synergistic therapy is validated in MRSA culture, MRSAinfected macrophage cells. Collectively, these findings highlight broad applications of staphyloxanthin photobleaching for treatment of MRSA infections.

Thickness independent reduced forming voltage in oxygen engineered HfO{sub 2} based resistive switching memories

Energy Technology Data Exchange (ETDEWEB)

Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Komissinskiy, P.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-08-18

The conducting filament forming voltage of stoichiometric hafnium oxide based resistive switching layers increases linearly with layer thickness. Using strongly reduced oxygen deficient hafnium oxide thin films grown on polycrystalline TiN/Si(001) substrates, the thickness dependence of the forming voltage is strongly suppressed. Instead, an almost constant forming voltage of about 3 V is observed up to 200 nm layer thickness. This effect suggests that filament formation and switching occurs for all samples in an oxidized HfO{sub 2} surface layer of a few nanometer thickness while the highly oxygen deficient thin film itself merely serves as a oxygen vacancy reservoir.

Contact resistance and overlapping capacitance in flexible sub-micron long oxide thin-film transistors for above 100 MHz operation

Energy Technology Data Exchange (ETDEWEB)

Münzenrieder, Niko, E-mail: muenzenrieder@ife.ee.ethz.ch; Salvatore, Giovanni A.; Petti, Luisa; Zysset, Christoph; Büthe, Lars; Vogt, Christian; Cantarella, Giuseppe; Tröster, Gerhard [Electronics Laboratory Swiss Federal Institute of Technology (ETH) Zürich, Gloriastrasse 35, 8092 Zürich (Switzerland)

2014-12-29

In recent years new forms of electronic devices such as electronic papers, flexible displays, epidermal sensors, and smart textiles have become reality. Thin-film transistors (TFTs) are the basic blocks of the circuits used in such devices and need to operate above 100 MHz to efficiently treat signals in RF systems and address pixels in high resolution displays. Beyond the choice of the semiconductor, i.e., silicon, graphene, organics, or amorphous oxides, the junctionless nature of TFTs and its geometry imply some limitations which become evident and important in devices with scaled channel length. Furthermore, the mechanical instability of flexible substrates limits the feature size of flexible TFTs. Contact resistance and overlapping capacitance are two parasitic effects which limit the transit frequency of transistors. They are often considered independent, while a deeper analysis of TFTs geometry imposes to handle them together; in fact, they both depend on the overlapping length (L{sub OV}) between source/drain and the gate contacts. Here, we conduct a quantitative analysis based on a large number of flexible ultra-scaled IGZO TFTs. Devices with three different values of overlap length and channel length down to 0.5 μm are fabricated to experimentally investigate the scaling behavior of the transit frequency. Contact resistance and overlapping capacitance depend in opposite ways on L{sub OV}. These findings establish routes for the optimization of the dimension of source/drain contact pads and suggest design guidelines to achieve megahertz operation in flexible IGZO TFTs and circuits.

Preparation and characteristics of a flexible neutron and γ-ray shielding and radiation-resistant material reinforced by benzophenone

Directory of Open Access Journals (Sweden)

Pin Gong

2018-04-01

Full Text Available With a highly functional methyl vinyl silicone rubber (VMQ matrix and filler materials of B4C, PbO, and benzophenone (BP and through powder surface modification, silicone rubber mixing, and vulcanized molding, a flexible radiation shielding and resistant composite was prepared in the study. The dispersion property of the powder in the matrix filler was improved by powder surface modification. BP was added into the matrix to enhance the radiation resistance performance of the composites. After irradiation, the tensile strength, elongation, and tear strength of the composites decreased, while the Shore hardness of the composites and the crosslinking density of the VMQ matrix increased. Moreover, the composites with BP showed better mechanical properties and smaller crosslinking density than those without BP after irradiation. The initial degradation temperatures of the composites containing BP before and after irradiation were 323.6°C and 335.3°C, respectively. The transmission of neutrons for a 2-mm thick sample was only 0.12 for an Am–Be neutron source. The transmission of γ-rays with energies of 0.662, 1.173, and 1.332 MeV for 2-cm thick samples were 0.7, 0.782, and 0.795, respectively. Keywords: Flexible Composite, Neutron Shielding, Radiation Resistance, γ-ray Shielding

Induction of radiation resistance and radio-protective mechanism. On the reactive oxygen and free radical

International Nuclear Information System (INIS)

Yukawa, Osami

2003-01-01

Radical scavenging system for reactive oxygen species (ROS) leading to radio-protection is reviewed on findings in animals, tissues and cells. Protection against oxygen toxicity in evolution can be seen in anaerobes' superoxide dismutase (SOD) over 3500 million years ago. ROS is generated endogenously and also by radiation. However, the intracellular sites of the generated ROS are different depending on its cause. The protection is done through enzymes like SOD, peroxidase, catalase, glutathione-related enzymes and through substances like GSH, α-tocopherol, ascorbic acid etc. Induction of ROS scavenging substances related with radio-resistance includes the responses to the low dose radiation (5-50 cGy) in those enzymes described above; to middle to high dose radiation (1-30 Gy) in a similar and in other unknown mechanisms; to exposure of ROS like H 2 O 2 at low concentration; and to antioxidant treatment. The cross-resistance between radiation and drugs suggests necessity of this induction. (N.I.)

49 CFR 178.940 - Standards for flexible Large Packagings.

Science.gov (United States)

2010-10-01

.... Flexible Large Packagings types are designated: (1) 51H flexible plastics. (2) 51M flexible paper. (b... this subchapter, flexible Large Packaging must be resistant to aging and degradation caused by ultraviolet radiation. (5) For plastic flexible Large Packagings, if necessary, protection against ultraviolet...

EFFECT OF MODERATE ALTITUDE ON PERIPHERAL MUSCLE OXYGENATION DURING LEG RESISTANCE EXERCISE IN YOUNG MALES

Directory of Open Access Journals (Sweden)

Toshio Matsuoka

2004-09-01

Full Text Available Training at moderate altitude (~1800m is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL. The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 - 21 yr performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL. They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb in the vastus lateralis muscle, arterial oxygen saturation (SpO2, and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws and pulse oximetry, respectively. Changes in OxyHb were expressed by Deff defined as the relative index of the maximum change ratio (% from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The Deff during exercise was significantly (p < 0.001 lower at 1800AL (60.4 ± 6.2 % than at near SL (74.4 ± 7.6 %. SpO2 during exercise was significantly (p < 0.001 lower at 1800AL (92.0 ± 1.7 % than at near SL (96.7 ± 1.2 %. Differences (SL - 1800AL in Deff during exercise correlated fairly strongly with differences in SpO2 during exercise (r = 0.660. These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore , that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.

Effects of Piezoelectric Potential of ZnO on Resistive Switching Characteristics of Flexible ZnO/TiO2 Heterojunction Cells

Science.gov (United States)

Li, Hongxia; Zhou, You; Du, Gang; Huang, Yanwei; Ji, Zhenguo

2018-03-01

Flexible resistance random access memory (ReRAM) devices with a heterojunction structure of PET/ITO/ZnO/TiO2/Au were fabricated on polyethylene terephthalate/indium tin oxide (PET/ITO) substrates by different physical and chemical preparation methods. X-ray diffraction, scanning electron microscopy and atomic force microscopy were carried out to investigate the crystal structure, surface topography and cross-sectional structure of the prepared films. X-ray photoelectron spectroscopy was also used to identify the chemical state of Ti, O and Zn elements. Theoretical and experimental analyses were conducted to identify the effect of piezoelectric potential of ZnO on resistive switching characteristics of flexible ZnO/TiO2 heterojunction cells. The results showed a pathway to enhance the performance of ReRAM devices by engineering the interface barrier, which is also feasible for other electronics, optoelectronics and photovoltaic devices.

Dependence of atomic oxygen resistance and the tribological properties on microstructures of WS2 films

International Nuclear Information System (INIS)

Xu, Shusheng; Gao, Xiaoming; Hu, Ming; Sun, Jiayi; Jiang, Dong; Wang, Desheng; Zhou, Feng; Weng, Lijun; Liu, Weimin

2014-01-01

Graphical abstract: - Highlights: • Pure WS 2 and WS 2 -Al composite films with different structures were prepared. • The compactness of WS 2 film was significantly improved due to incorporation of Al. • Different mechanisms of atomic oxygen resistance of both the films were discussed. • Films before and after AO irradiation kept the unchanged tribological properties. • The composite films showed much better wear resistance than pure WS 2 film. - Abstract: To study the anti-oxidation mechanism of WS 2 films, the pure WS 2 , and Al doped WS 2 composite films were prepared via radio frequency sputtering and the atomic oxygen (AO) irradiation tests were conducted using a ground AO simulation facility. The tribological properties of both films before and after AO irradiation were evaluated using vacuum ball-on-disk tribo-tester. The incorporation of a small fraction of Al dopant resulted in microstructure change from loose columnar platelet with significant porosity for pure WS 2 film to very dense structure. In pure WS 2 film, WS 2 exists as crystalline phase with edge-plane preferential orientation, but nanocrystalline and amorphous phase coexists for the WS 2 -Al composite film. Even if large amount of AO transported into the interior through the longitudinal pores, the pure film showed good AO irradiation resistance owing to the basal plane of WS 2 crystal exhibiting much higher anti-oxidation capacity than the edge-plane. The composite film also had excellent AO irradiation resistance due to the formation of effective thinner WO 3 cladding layer in the sub-surface layer. Tribological results revealed that the composite films showed a significantly improved wear resistance, in comparison to the pure WS 2 film. Besides, due to the effective AO resistance, the tribological properties of WS 2 films remained almost unchanged before and after AO irradiation

Forming-free performance of a-SiN x :H-based resistive switching memory obtained by oxygen plasma treatment

Science.gov (United States)

Zhang, Xinxin; Ma, Zhongyuan; Zhang, Hui; Liu, Jian; Yang, Huafeng; Sun, Yang; Tan, Dinwen; Li, Wei; Xu, Ling; Chen, Kuiji; Feng, Duan

2018-06-01

An a-SiN x -based resistive random access memory (RRAM) device with a forming-free characteristic has significant potentials for the industrialization of the next-generation memories. We demonstrate that a forming-free a-SiN x O y RRAM device can be achieved by an oxygen plasma treatment of ultra-thin a-SiN x :H films. Electron spin resonance spectroscopy reveals that Si dangling bonds with a high density (1019 cm‑3) are distributed in the initial state, which exist in the forms of Si2N≡Si·, SiO2≡Si·, O3≡Si·, and N3≡Si·. X-ray photoelectron spectroscopy and temperature-dependent current analyses reveal that the silicon dangling bonds induced by the oxygen plasma treatment and external electric field contribute to the low resistance state (LRS). For the high resistance state (HRS), the rupture of the silicon dangling bond pathway is attributed to the partial passivation of Si dangling bonds by H+ and O2‑. Both LRS and HRS transmissions obey the hopping conduction model. The proposed oxygen plasma treatment, introduced to generate a high density of Si dangling bonds in the SiN x O y :H films, provides a new approach to forming-free RRAM devices.

High-flexibility, noncollapsing lightweight hose

Science.gov (United States)

Williams, D.A.

1993-04-20

A high-flexibility, noncollapsing, lightweight, large-bore, wire-reinforced hose is inside fiber-reinforced PVC tubing that is flexible, lightweight, and abrasion resistant. It provides a strong, kink- and collapse-free conduit for moving large quantities of dangerous fluids, e.g., removing radioactive waste water or processing chemicals.

In-plane dissipation maxima and vortex-line distortions in the resistive transitions of oxygen-doped Bi2Sr2CaCu2O(8+delta) single crystals

Science.gov (United States)

Hsu, J. W. P.; Mitzi, D. B.; Kapitulnik, A.; Lee, Mark

1991-10-01

Measurements of the in-plane resistive transition of Bi2Sr2CaCu2O(8+delta) single crystals in perpendicular magnetic fields reveal that in oxygen-reduced samples a giant resistance maximum evolves with field. This is not seen in oxygenated samples with similar metallic normal resistivities. As the peak resistivity may exceed the normal resistivity, it cannot arise from ordinary vortex-motion dissipation. A model is proposed where the excess resistance results from nonrigid vortex motion coupling the out-of-plane dissipation to the in-plane resistance at temperatures where pinning effects are negligible.

Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

Energy Technology Data Exchange (ETDEWEB)

Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

2016-04-01

Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

Effect of oxygen defects on transport properties and Tc of YBa2Cu3O6+x: Displacement energy for plane and chain oxygen and implications for irradiation-induced resistivity and Tc suppression

International Nuclear Information System (INIS)

Tolpygo, S.K.; Lin, J.; Gurvitch, M.; Hou, S.Y.; Phillips, J.M.

1996-01-01

The effect of electron irradiation with energy from 20 to 120 keV on the resistivity, Hall coefficient, and superconducting critical temperature T c of YBa 2 Cu 3 O 6+x thin films has been studied. The threshold energy of incident electrons for T c suppression has been found, and the displacement energy for oxygen in CuO 2 planes has been evaluated as 8.4 eV for irradiation along the c axis. The kinetics of production of the in-plane oxygen vacancies has been studied and found to be governed by athermal recombination of vacancy-interstitial pairs. The evaluated recombination volume constitutes about 21 unit cells. The increase in the T-linear resistivity slope and Hall coefficient at unchanged T c was observed in irradiations with subthreshold incident energies and was ascribed to the effect of chain oxygen displacements. The upper limit on the displacement energy for chain oxygen has been estimated as 2.8 eV. In x=0.9 samples the T c suppression by in-plane oxygen defects and increase in residual resistivity have been found to be, respectively, -280 K and 1.5 mΩcm per defect in the unit cell. It is shown that T c suppression by in-plane oxygen defects is a universal function of the transport impurity scattering rate and can be described qualitatively by pair-breaking theory for d-wave superconductors with nonmagnetic potential scatterers. Evaluation of scattering and pair-breaking rates as well as the scattering cross section and potential is given. A comparison of the influence of in-plane oxygen defects on transport properties with that of other in-plane defects, such as Zn and Ni substitutions for Cu, is also made. copyright 1996 The American Physical Society

Combining the Converse Humidity/Resistance Response Behaviors of RGO Films for Flexible Logic Devices

KAUST Repository

Tai, Yanlong

2017-03-23

Carbon nanomaterials have excellent humidity sensing performance. Here, we demonstrate that reduced-graphene-oxide- (rGO) based conductive films with different thermal reduction times have gradient and invertible humidity/electrical resistance responses: rGO films (< 11 h, negative response, regarded as a signal of “0”), rGO films (around 11-13 h, balance point) and rGO films (> 13 h, negative response, regarded as a signal of “1”). We propose a new mechanism that describes a “scale”-like model for rGO films to explain these behaviors based on contributions from Ohm-contact resistance and capacitive reactance at interplate junctions, and intrinsic resistances of the nanoplates, respectively. This mechanism is accordingly validated via a series of experiments and electrical impedance spectroscopies, which complement more classical models based on proton conductivity. To explore the practical applications of the converse humidity/resistance responses, three simple flexible logic devices were developed, i) a rGO pattern for humidity-insensitive conductive film, which has the potential to greatly improve the stability of carbon-based electrical device to humidity; ii) a Janus pattern of rGO films for gesture recognition, which is very useful to human/machine interactions; iii) a sandwich pattern of rGO films for 3-dimensional (3D) noncontact sensing, which will be complementary to existing 3D touch technique.

End-tidal carbon dioxide monitoring during flexible fiberoptic ...

African Journals Online (AJOL)

In recent years, flexible fiberoptic bronchoscopy (FFB) has been applied for diagnostic and some therapeutic purposes. During FFB and even in the presence of supplemental oxygen, hypoventilation leading to hypoxia and desaturation may occur; this is aggravated by the use of suction. Arterial oxygen saturation is usually ...

Improvement of the Oxidation Resistance of CoNiCrAlY Bond Coats Sprayed by High Velocity Oxygen-Fuel onto Nickel Superalloy Substrate

Directory of Open Access Journals (Sweden)

Alessio Fossati

2010-11-01

Full Text Available CoNiCrAlY powders with similar granulometry and chemical composition, but different starting reactivity toward oxygen, were sprayed onto superalloy substrates by High Velocity Oxygen-Fuel producing coatings of similar thicknesses. After spraying, samples were maintained at 1,273 K in air for different test periods of up to 5,000 hours. Morphological, microstructural, compositional and electrochemical analyses were performed on the coated samples in order to assess the high temperature oxidation resistance provided by the two different powders. The powder with higher starting reactivity towards oxygen improves the oxidation resistance of the coated samples by producing thinner and more adherent thermally grown oxide layers.

Influence of argon and oxygen pressure ratio on bipolar-resistive switching characteristics of CeO2- x thin films deposited at room temperature

Science.gov (United States)

Ismail, Muhammad; Ullah, Rehmat; Hussain, Riaz; Talib, Ijaz; Rana, Anwar Manzoor; Hussain, Muhammad; Mahmood, Khalid; Hussain, Fayyaz; Ahmed, Ejaz; Bao, Dinghua

2018-02-01

Cerium oxide (CeO2-x) film was deposited on Pt/Ti/SiO2/Si substrate by rf magnetron sputtering at room temperature. Resistive switching characteristics of these ceria films have been improved by increasing oxygen content during deposition process. Endurance and statistical analyses indicate that the operating stability of CeO2-x-based memory is highly dependent on the oxygen content. Results indicate that CeO2-x film-based RRAM devices exhibit optimum performance when fabricated at an argon/oxygen ratio of 6:24. An increase in the oxygen content introduced during CeO2-x film deposition not only stabilizes the conventional bipolar RS but also improves excellent switching uniformity such as large ON/OFF ratio (102), excellent switching device-to-device uniformity and good sweep endurance over 500 repeated RS cycles. Conduction in the low-resistance state (LRS) as well as in the low bias field region in the high-resistance state (HRS) is found to be Ohmic and thus supports the conductive filament (CF) theory. In the high voltage region of HRS, space charge limited conduction (SCLC) and Schottky emission are found to be the dominant conduction mechanisms. A feasible filamentary RS mechanism based on the movement of oxygen ions/vacancies under the bias voltage has been discussed.

Melting of corrosion–resisting steels using air in bath agitation at the end of oxygen blowing

International Nuclear Information System (INIS)

Gizatulin, R A; Valuev, D V; Valueva, A V; Yedesheva, Ch V

2014-01-01

A number of metallurgical plants employ ladle stirring with argon at the end of oxygen blowing during the melting process of corrosion–resisting steels [1, 2]. At the same time, the scarcity and relatively high cost of argon, its low pressure in a shop air pipeline restrain most plants from using argon for corrosion–resisting steel production. Compressed air was used instead of argon to intensify the process of decarbonizing when chromium–nickel stainless steels were made with a 40–ton electric arc furnace at the Kuznetsk Metallurgical Plant

Using Dopants to Tune Oxygen Vacancy Formation in Transition Metal Oxide Resistive Memory.

Science.gov (United States)

Jiang, Hao; Stewart, Derek A

2017-05-17

Introducing dopants is an important way to tailor and improve electronic properties of transition metal oxides used as high-k dielectric thin films and resistance switching layers in leading memory technologies, such as dynamic and resistive random access memory (ReRAM). Ta 2 O 5 has recently received increasing interest because Ta 2 O 5 -based ReRAM demonstrates high switching speed, long endurance, and low operating voltage. However, advances in optimizing device characteristics with dopants have been hindered by limited and contradictory experiments in this field. We report on a systematic study on how various metal dopants affect oxygen vacancy formation in crystalline and amorphous Ta 2 O 5 from first principles. We find that isoelectronic dopants and weak n-type dopants have little impact on neutral vacancy formation energy and that p-type dopants can lower the formation energy significantly by introducing holes into the system. In contrast, n-type dopants have a deleterious effect and actually increase the formation energy for charged oxygen vacancies. Given the similar doping trend reported for other binary transition metal oxides, this doping trend should be universally valid for typical binary transition metal oxides. Based on this guideline, we propose that p-type dopants (Al, Hf, Zr, and Ti) can lower the forming/set voltage and improve retention properties of Ta 2 O 5 ReRAM.

Oxygen plasma treatment and deposition of CNx on a fluorinated polymer matrix composite for improved erosion resistance

International Nuclear Information System (INIS)

Muratore, C.; Korenyi-Both, A.; Bultman, J. E.; Waite, A. R.; Jones, J. G.; Storage, T. M.; Voevodin, A. A.

2007-01-01

The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CN x coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CN x was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the surface. In situ x-ray photoelectron spectroscopy was used to evaluate the effect of the plasma treatment on surface chemistry, and electron microscopy was used to identify changes in the surface morphology of the PMC substrate after plasma exposure. The fluorine concentration at the surface was significantly reduced and the carbon fibers were exposed after plasma treatment. CN x coatings were then deposited on oxygen treated PMC substrates. Qualitative tests demonstrated that plasma treatment improved coating adhesion resulting in an erosion resistance improvement of a factor of 2 compared to untreated coated composite substrates. The combination of PMC pretreatment and coating with CN x reduced the erosion rate by an order of magnitude for normally incident particles

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

Energy Technology Data Exchange (ETDEWEB)

Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

International Nuclear Information System (INIS)

Yarmonenko, S.P.; Ehpshtejn, I.M.

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

KAUST Repository

Semple, James; Wyatt-Moon, Gwenhivir; Georgiadou, Dimitra G.; McLachlan, Martyn A.; Anthopoulos, Thomas D.

2017-01-01

Electronic memory cells are of critical importance in modern-day computing devices, including emerging technology sectors such as large-area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low-temperature and large-area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As-prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios >10⁴ and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large-area electronics as well as in electronics for harsh environments, e.g., space, high/low temperature, magnetic influences, radiation, vibration, and pressure.

Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

KAUST Repository

Semple, James

2017-01-02

Electronic memory cells are of critical importance in modern-day computing devices, including emerging technology sectors such as large-area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low-temperature and large-area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As-prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios >10⁴ and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large-area electronics as well as in electronics for harsh environments, e.g., space, high/low temperature, magnetic influences, radiation, vibration, and pressure.

Electrical and optical properties of nitrogen doped SnO2 thin films deposited on flexible substrates by magnetron sputtering

International Nuclear Information System (INIS)

Fang, Feng; Zhang, Yeyu; Wu, Xiaoqin; Shao, Qiyue; Xie, Zonghan

2015-01-01

Graphical abstract: The best SnO 2 :N TCO film: about 80% transmittance and 9.1 × 10 −4 Ω cm. - Highlights: • Nitrogen-doped tin oxide film was deposited on PET by RF-magnetron sputtering. • Effects of oxygen partial pressure on the properties of thin films were investigated. • For SnO 2 :N film, visible light transmittance was 80% and electrical resistivity was 9.1 × 10 −4 Ω cm. - Abstract: Nitrogen-doped tin oxide (SnO 2 :N) thin films were deposited on flexible polyethylene terephthalate (PET) substrates at room temperature by RF-magnetron sputtering. Effects of oxygen partial pressure (0–4%) on electrical and optical properties of thin films were investigated. Experimental results showed that SnO 2 :N films were amorphous state, and O/Sn ratios of SnO 2 :N films were deviated from the standard stoichiometry 2:1. Optical band gap of SnO 2 :N films increased from approximately 3.10 eV to 3.42 eV as oxygen partial pressure increased from 0% to 4%. For SnO 2 :N thin films deposited on PET, transmittance was about 80% in the visible light region. The best transparent conductive oxide (TCO) deposited on flexible PET substrates was SnO 2 :N thin films preparing at 2% oxygen partial pressure, the transmittance was about 80% and electrical conductivity was about 9.1 × 10 −4 Ω cm

A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

Science.gov (United States)

McGuire, B J; Secomb, T W

2001-11-01

Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

Thin film oxygen partial pressure sensor

Science.gov (United States)

Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

1972-01-01

The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

Flexible heat pipes with integrated bioinspired design

Directory of Open Access Journals (Sweden)

Chao Yang

2015-02-01

Full Text Available In this work we report the facile fabrication and performance evaluation of flexible heat pipes that have integrated bioinspired wick structures and flexible polyurethane polymer connector design between the copper condenser and evaporator. Inside the heat pipe, a bioinspired superhydrophilic strong-base-oxidized copper mesh with multi-scale micro/nano-structures was used as the wicking material and deionized water was selected as working fluid. Thermal resistances of the fabricated flexible heat pipes charged with different filling ratios were measured under thermal power inputs ranging from 2 W to 12 W while the device was bent at different angles. The fabricated heat pipes with a 30% filling ratio demonstrated a low thermal resistance less than 0.01 K/W. Compared with the vertically oriented straight heat pipes, bending from 30° up to 120° has negligible influence on the heat-transfer performance. Furthermore, repeated heating tests indicated that the fabricated flexible heat pipes have consistent and reliable heat-transfer performance, thus would have important applications for advanced thermal management in three dimensional and flexible electronic devices.

Ion irradiation of AZO thin films for flexible electronics

Energy Technology Data Exchange (ETDEWEB)

Boscarino, Stefano; Torrisi, Giacomo; Crupi, Isodiana [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Alberti, Alessandra [CNR-IMM, via Strada VIII 5, 95121 Catania (Italy); Mirabella, Salvatore; Ruffino, Francesco [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Terrasi, Antonio, E-mail: antonio.terrasi@ct.infn.it [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy)

2017-02-01

Highlights: • Evidence of electrical good quality AZO ultra thin films without thermal annealing. • Evidence of the main role of Oxygen vs. structural parameters in controlling the electrical performances of AZO. • Evidence of the role of the ion irradiation in improving the electrical properties of AZO ultra thin films. • Synthesis of AZO thin films on flexible/plastic substrates with good electrical properties without thermal processes. - Abstract: Aluminum doped Zinc oxide (AZO) is a promising transparent conductor for solar cells, displays and touch-screen technologies. The resistivity of AZO is typically improved by thermal annealing at temperatures not suitable for plastic substrates. Here we present a non-thermal route to improve the electrical and structural properties of AZO by irradiating the TCO films with O{sup +} or Ar{sup +} ion beams (30–350 keV, 3 × 10{sup 15}–3 × 10{sup 16} ions/cm{sup 2}) after the deposition on glass and flexible polyethylene naphthalate (PEN). X-ray diffraction, optical absorption, electrical measurements, Rutherford Backscattering Spectrometry and Atomic Force Microscopy evidenced an increase of the crystalline grain size and a complete relief of the lattice strain upon ion beam irradiation. Indeed, the resistivity of thin AZO films irradiated at room temperature decreased of two orders of magnitude, similarly to a thermal annealing at 400 °C. We also show that the improvement of the electrical properties does not simply depend on the strain or polycrystalline domain size, as often stated in the literature.

Fabrication of graphene-nanoflake/poly(4-vinylphenol) polymer nanocomposite thin film by electrohydrodynamic atomization and its application as flexible resistive switching device

Energy Technology Data Exchange (ETDEWEB)

Choi, Kyung Hyun; Ali, Junaid [Department of Mechatronics Engineering, Jeju National University, Jeju 690-756 (Korea, Republic of); Na, Kyoung-Hoan, E-mail: khna@dankook.ac.kr [College of Engineering, Dankook University, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of)

2015-10-15

This paper describes synthesis of graphene/poly(4-vinylphenol) (PVP) nanocomposite and deposition of thin film by electrohydrodynamic atomization (EHDA) for fabrication flexible resistive switching device. EHDA technique proved its viability for thin film deposition after surface morphology analyses by field emission scanning electron microscope (FESEM) and non-destructive 3D Nano-profilometry, as the deposited films were, devoid of abnormalities. The commercially available graphene micro-flakes were exfoliated and broken down to ultra-small (20 nm–200 nm) nano-flakes by ultra-sonication in presence of N-methyl-pyrrolidone (NMP). These graphene nanoflakes with PVP nanocomposite, were successfully deposited as thin films (thickness ~140±7 nm, R{sub a}=2.59 nm) on indium–tin-oxide (ITO) coated polyethylene terephthalate (PET) substrate. Transmittance data revealed that thin films are up to ~87% transparent in visible and NIR region. Resistive switching behaviour of graphene/PVP nanocomposite thin film was studied by using the nanocomposite as active layer in Ag/active layer/ITO sandwich structure. The resistive switching devices thus fabricated, showed characteristic OFF to ON (high resistance to low resistance) transition at low voltages, when operated between ±3 V, characterized at 10 nA compliance currents. The devices fabricated by this approach exhibited a stable room temperature, low power current–voltage hysteresis and well over 1 h retentivity, and R{sub OFF}/R{sub ON}≈35:1. The device showed stable flexibility up to a minimum bending diameter of 1.8 cm.

Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

International Nuclear Information System (INIS)

Watanabe, Tomoyuki; Saotome, Masao; Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi; Funaki, Makoto; Hayashi, Hideharu

2014-01-01

Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ m ) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H 2 O 2 ), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ m depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H 2 O 2 -induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ m depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin-resistance. • Inhibition of DRP or ROS

Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Tomoyuki [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Saotome, Masao, E-mail: msaotome@hama-med.ac.jp [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Funaki, Makoto [Clinical Research Center for Diabetes, Tokushima University Hospital, 2-50-1 Kuramoto-cho, Tokushima 770-8503 (Japan); Hayashi, Hideharu [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan)

2014-05-01

Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ{sub m}) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H{sub 2}O{sub 2}), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ{sub m} depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H{sub 2}O{sub 2}-induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ{sub m} depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin-resistance

Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels.

Science.gov (United States)

Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

2016-09-28

We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels

Science.gov (United States)

Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

2016-09-01

We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

[Strength, flexibility, balance, resistance and flexibility assessment according to body mass index in active older women].

Science.gov (United States)

Vaquero-Cristóbal, Raquel; Martínez González-Moro, Ignacio; Alacid Cárceles, Fernando; Ros Simón, Esperanza

2013-01-01

Overweight and obesity are increasing at an alarming rate among older people. This is mainly because this population is predominantly sedentary. The aim of this study was to classify, according to the body mass index (BMI), a group of older active women and to evaluate the different basic physical abilities as a function of this. The BMI and fitness were evaluated in 60 elderly active women (mean age: 66.14 ± 6.59 years) using the 2-minute step test, arm curl test, chair stand test, back scratch test, chair-sit and reach-test, flamenco test, and 8-foot up-and-go test. It was found that 52.23% of the women studied had a normal BMI and 47.76% were slightly overweight. There were no cases of obesity or underweight. Women with normal BMI had better values in all tests than overweight women. Significant differences were found in the flamenco test (P<.05), and 8-foot up-and-go test (P<.01). Older women who usually do physical activity had a normal or slightly overweight BMI. It was also found that women with lower BMI have better resistance, flexibility, balance and strength. Copyright © 2012 SEGG. Published by Elsevier Espana. All rights reserved.

Hierarchically Designed 3D Holey C2N Aerogels as Bifunctional Oxygen Electrodes for Flexible and Rechargeable Zn-Air Batteries.

Science.gov (United States)

Shinde, Sambhaji S; Lee, Chi Ho; Yu, Jin-Young; Kim, Dong-Hyung; Lee, Sang Uck; Lee, Jung-Ho

2018-01-23

The future of electrochemical energy storage spotlights on the designed formation of highly efficient and robust bifunctional oxygen electrocatalysts that facilitate advanced rechargeable metal-air batteries. We introduce a scalable facile strategy for the construction of a hierarchical three-dimensional sulfur-modulated holey C 2 N aerogels (S-C 2 NA) as bifunctional catalysts for Zn-air and Li-O 2 batteries. The S-C 2 NA exhibited ultrahigh surface area (∼1943 m 2 g -1 ) and superb electrocatalytic activities with lowest reversible oxygen electrode index ∼0.65 V, outperforms the highly active bifunctional and commercial (Pt/C and RuO 2 ) catalysts. Density functional theory and experimental results reveal that the favorable electronic structure and atomic coordination of holey C-N skeleton enable the reversible oxygen reactions. The resulting Zn-air batteries with liquid electrolytes and the solid-state batteries with S-C 2 NA air cathodes exhibit superb energy densities (958 and 862 Wh kg -1 ), low charge-discharge polarizations, excellent reversibility, and ultralong cycling lives (750 and 460 h) than the commercial Pt/C+RuO 2 catalysts, respectively. Notably, Li-O 2 batteries with S-C 2 NA demonstrated an outstanding specific capacity of ∼648.7 mA h g -1 and reversible charge-discharge potentials over 200 cycles, illustrating great potential for commercial next-generation rechargeable power sources of flexible electronics.

The Escherichia coli BtuE protein functions as a resistance determinant against reactive oxygen species.

Directory of Open Access Journals (Sweden)

Felipe A Arenas

2011-01-01

Full Text Available This work shows that the recently described Escherichia coli BtuE peroxidase protects the bacterium against oxidative stress that is generated by tellurite and by other reactive oxygen species elicitors (ROS. Cells lacking btuE (ΔbtuE displayed higher sensitivity to K(2TeO(3 and other oxidative stress-generating agents than did the isogenic, parental, wild-type strain. They also exhibited increased levels of cytoplasmic reactive oxygen species, oxidized proteins, thiobarbituric acid reactive substances, and lipoperoxides. E. coli ΔbtuE that was exposed to tellurite or H(2O(2 did not show growth changes relative to wild type cells either in aerobic or anaerobic conditions. Nevertheless, the elimination of btuE from cells deficient in catalases/peroxidases (Hpx(- resulted in impaired growth and resistance to these toxicants only in aerobic conditions, suggesting that BtuE is involved in the defense against oxidative damage. Genetic complementation of E. coli ΔbtuE restored toxicant resistance to levels exhibited by the wild type strain. As expected, btuE overexpression resulted in decreased amounts of oxidative damage products as well as in lower transcriptional levels of the oxidative stress-induced genes ibpA, soxS and katG.

High-resolution and high-conductive electrode fabrication on a low thermal resistance flexible substrate

International Nuclear Information System (INIS)

Kang, Bongchul; Kno, Jinsung; Yang, Minyang

2011-01-01

Processes based on the liquid-state pattern transfer, like inkjet printing, have critical limitations including low resolution and low electrical conductivity when fabricating electrodes on low thermal resistance flexible substrates such as polyethylene terephthalate (PET). Those are due to the nonlinear transfer mechanism and the limit of the sintering temperature. Although the laser direct curing (LDC) of metallic inks is an alternative process to improve the resolution, it is also associated with the disadvantages of causing thermal damage to the polymer substrate. This paper suggests the laser induced pattern adhesion transfer method to fabricate electrodes of both high electrical conductivity and high resolution on a PET substrate. First, solid patterns are cost-effectively created by the LDC of the organometallic silver ink on a glass that is optically and thermally stable. The solid patterns sintered on the glass are transferred to the PET substrate by the photo-thermally generated adhesion force of the substrate. Therefore, we achieved electrodes with a minimum line width of 10 µm and a specific resistance of 3.6 μΩcm on the PET substrate. The patterns also showed high mechanical reliability

High-resolution and high-conductive electrode fabrication on a low thermal resistance flexible substrate

Science.gov (United States)

Kang, Bongchul; Kno, Jinsung; Yang, Minyang

2011-07-01

Processes based on the liquid-state pattern transfer, like inkjet printing, have critical limitations including low resolution and low electrical conductivity when fabricating electrodes on low thermal resistance flexible substrates such as polyethylene terephthalate (PET). Those are due to the nonlinear transfer mechanism and the limit of the sintering temperature. Although the laser direct curing (LDC) of metallic inks is an alternative process to improve the resolution, it is also associated with the disadvantages of causing thermal damage to the polymer substrate. This paper suggests the laser induced pattern adhesion transfer method to fabricate electrodes of both high electrical conductivity and high resolution on a PET substrate. First, solid patterns are cost-effectively created by the LDC of the organometallic silver ink on a glass that is optically and thermally stable. The solid patterns sintered on the glass are transferred to the PET substrate by the photo-thermally generated adhesion force of the substrate. Therefore, we achieved electrodes with a minimum line width of 10 µm and a specific resistance of 3.6 μΩcm on the PET substrate. The patterns also showed high mechanical reliability.

Paclitaxel-resistant HeLa cells have up-regulated levels of reactive oxygen species and increased expression of taxol resistance gene 1.

Science.gov (United States)

Bi, Wenxiang; Wang, Yuxia; Sun, Gaoying; Zhang, Xiaojin; Wei, Yongqing; Li, Lu; Wang, Xiaoyuan

2014-07-01

This study is to establish a paclitaxel (PTX)-resistant human cervical carcinoma HeLa cell line (HeLa/PTX) and to investigate its redox characteristics and the expression of taxol resistance gene 1 (Txr1). HeLa cells were treated with PTX and effects of PTX on cell proliferation were detected through cell counting and the MTT assay. Levels of cellular reactive oxygen species (ROS), reduced glutathione (GSH), and oxidized glutathione (GSSG) as well as the ratio of GSH to GSSG were measured by the 2,7-difluorescein diacetate (DCFH-DA) method and the 5,5'dithiobis(2-nitrobenzoic acid) (DTNB) method. Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined by the nitrite formation method, the molybdate colorimetric method, and the DTNB colorimetric method, respectively. The level of Txr1 mRNA was determined by real-time PCR. Compared with the regular HeLa cells, HeLa/PTX cells were larger in size and had more cytoplasmic granules. The population doubling time for HeLa/PTX cells was 1.32 times of that of HeLa cells (PHeLa/PTX cells showed stronger resistance to PTX than HeLa cells with a resistance index of 122.69. HeLa/PTX cells had higher levels of ROS (PHeLa cells. HeLa/PTX cells, with higher levels of ROS and Txr1 mRNA expression, are more resistant to PTX than HeLa cells.

Oxygen vacancy effects in HfO2-based resistive switching memory: First principle study

Directory of Open Access Journals (Sweden)

Yuehua Dai

2016-08-01

Full Text Available The work investigated the shape and orientation of oxygen vacancy clusters in HfO2-base resistive random access memory (ReRAM by using the first-principle method based on the density functional theory. Firstly, the formation energy of different local Vo clusters was calculated in four established orientation systems. Then, the optimized orientation and charger conductor shape were identified by comparing the isosurface plots of partial charge density, formation energy, and the highest isosurface value of oxygen vacancy. The calculated results revealed that the [010] orientation was the optimal migration path of Vo, and the shape of system D4 was the best charge conductor in HfO2, which effectively influenced the SET voltage, formation voltage and the ON/OFF ratio of the device. Afterwards, the PDOS of Hf near Vo and total density of states of the system D4_010 were obtained, revealing the composition of charge conductor was oxygen vacancy instead of metal Hf. Furthermore, the migration barriers of the Vo hopping between neighboring unit cells were calculated along four different orientations. The motion was proved along [010] orientation. The optimal circulation path for Vo migration in the HfO2 super-cell was obtained.

Surface modification of carbon/epoxy prepreg using oxygen plasma and its effect on the delamination resistance behavior of carbon/epoxy composites

International Nuclear Information System (INIS)

Kim, M.H.; Rhee, K.Y.; Kim, H.J.; Jung, D.H.

2007-01-01

It was shown in previous study that the fracture toughness of carbon/epoxy laminated composites could be significantly improved by modifying the surface of the prepreg using Ar + irradiation in an oxygen environment. In this study, the surface of carbon/epoxy prepreg was modified using an oxygen plasma to improve the delamination resistance behavior of carbon/epoxy laminated composites. The variation of the contact angle on the prepreg surface was determined as a function of the modification time, in order to determine the optimal modification time. An XPS analysis was conducted to investigate the chemical changes on the surface of the prepreg caused by the plasma modification. Mode I delamination resistance curves of the composites with and without surface modification were plotted as a function of the delamination increment. The results showed that the contact angle varied from ∼64 o to ∼47 o depending on the modification time and reached a minimum for a modification time of 30 min. The XPS analysis showed that the hydrophilic carbonyl C=O group was formed by the oxygen plasma modification. The results also showed that the delamination resistance behavior was significantly improved by the plasma modification of the prepreg. This improvement was caused by the better layer-to-layer adhesion as well as increased interfacial strength between the fibers and matrix

Modulation of resistive switching characteristics for individual BaTiO3 microfiber by surface oxygen vacancies

Science.gov (United States)

Miao, Zhilei; Chen, Lei; Zhou, Fang; Wang, Qiang

2018-01-01

Different from traditional thin-film BaTiO3 (BTO) RRAM device with planar structure, individual microfiber-shaped RRAM device, showing promising application potentials in the micro-sized non-volatile memory system, has not been investigated so far to demonstrate resistive switching behavior. In this work, individual sol-gel BTO microfiber has been formed using the draw-bench method, followed by annealing in different atmospheres of air and argon, respectively. The resistive switching characteristics of the individual BTO microfiber have been investigated by employing double-probe SEM measurement system, which shows great convenience to test local electrical properties by modulating the contact sites between the W probes and the BTO microfiber. For the sample annealed in air, the average resistive ON/OFF ratio is as high as 108, enhanced about four orders in comparison with the counterpart that annealed in Argon. For the sample annealed in argon ambience, the weakened resistive ON/OFF ratio can be attributed to the increased presence of oxygen vacancies in the surface of BTO fibers, and the underlying electrical conduction mechanisms are also discussed.

An oxygen-insensitive degradable resist for fabricating metallic patterns on highly curved surfaces by UV-nanoimprint lithography.

Science.gov (United States)

Hu, Xin; Huang, Shisong; Gu, Ronghua; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng

2014-10-01

In this paper, an oxygen-insensitive degradable resist for UV-nanoimprint is designed, com-prising a polycyclic degradable acrylate monomer, 2,10-diacryloyloxymethyl-1,4,9,12-tetraoxa-spiro [4.2.4.2] tetradecane (DAMTT), and a multifunctional thiol monomer pentaerythritol tetra(3-mercaptopropionate) (PETMP). The resist can be quickly UV-cured in the air atmosphere and achieve a high monomer conversion of over 98%, which greatly reduce the adhesion force between the resist and the soft mold. High conversion, in company with an adequate Young's modulus (about 1 GPa) and an extremely low shrinkage (1.34%), promises high nanoimprint resolution of sub-50 nm. The cross-linked resist is able to break into linear molecules in a hot acid solvent. As a result, metallic patterns are fabricated on highly curved surfaces via the lift off process without the assistance of a thermoplastic polymer layer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of the oxygen-vacancy (A-center) defect complex profile in neutron irradiated high resistivity silicon junction particle detectors

International Nuclear Information System (INIS)

Li, Zheng; Kraner, H.W.; Verbitskaya, E.; Eremin, V.; Ivanov, A.; Rubinelli, F.A.; Fonash, S.J.

1992-02-01

Distributions of the A-center (oxygen-vacancy) in neutron silicon detectors have been studied using Deep Level Transient Spectroscopy. A-centers have been found to be nearly uniformly distributed in the silicon water depth for medium resistivity (0.1 - 0.2 kΩ-cm) silicon detectors. A positive filling pulse was needed to detect the A-centers in high resistivity (>4 kΩ-cm) silicon detectors, and this effect was found to be dependent on the oxidation temperature. A discussion of this effect is presented. 16 refs

A flexible infrared sensor for tissue oximetry

DEFF Research Database (Denmark)

Petersen, Søren Dahl; Thyssen, Anders; Engholm, Mathias

2013-01-01

We present a flexible infrared sensor for use in tissue oximetry with the aim of treating prematurely born infants. The sensor will detect the oxygen saturation in brain tissue through near infrared spectroscopy. The sensor itself consists of several individual silicon photo detectors fully...

A high reliability oxygen deficiency monitoring system

International Nuclear Information System (INIS)

Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

1993-05-01

The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

A high reliability oxygen deficiency monitoring system

International Nuclear Information System (INIS)

Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

1993-01-01

The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

Sensitivity of clostridium acetobutylicum to oxygen and ionizing radiation

International Nuclear Information System (INIS)

Sozer, A.C.; Adler, H.I.; Machanoff, R.; Haney, S.

1984-01-01

The authors are studying the sensitivity of four strains of the obligate anaerobe, Clostridium acetobutylicum, to oxygen and ionizing radiation. Anaerobic bacteria are useful for such studies because of the absence of elaborate oxygen detoxification mechanisms that are found in aerobes. Their experiments make use of sterile membrane fragments from Escherichia coli that rapidly remove molecular oxygen from media and permit growth of anaerobes without the use of reducing agents or anaerobic chambers. Of the four strains examined for sensitivity to ionizing radiation under anaerobic conditions, one has an LD/sub 50/ of -- 25 krads and the others have an LD/sub 50/ of -- 7 krads. The radiation resistant strain is also relatively resistant to oxygen exposure. Sensitivity to oxygen was determined by diluting cells in buffer at 28 0 and bubbling with air. An exposure to air for 40 min induced only slight inactivation in the radiation resistant strain. All strains are capable of removing oxygen from complex media but there is no apparent correlation between this oxygen consuming reaction and inactivation by either oxygen or radiation

Flexible Connection Elastomeric Rubber as a Pounding Resisting Element between Two Adjacent Buildings

Directory of Open Access Journals (Sweden)

Yuskar Lase

2013-03-01

Full Text Available To solve pounding problem of two adjacent buildings, structural designer usually employs a dilatation between the structures or make the two structures as a monolith structure. Other alternative is by using an elastomeric rubber as a pounding resisting element between the two structures. Effectiveness in applying elastomeric rubber component as flexible connection of two adjacent structures is the main focus of this paper. Various simulations such as structure models, earthquake excitations and openings in gap element are studied. Observation of maximum structural responses will be performed for structure model with elastomeric rubber in comparison with (1 monolith structure model and (2 structure model with rigid element (steel element. Simulation results show that application of elastomeric rubber component to prevent structures from pounding problem provides advantages especially in reducing internal forces in the shorter building. However, it slightly increases displacement of both structures.

Anomalous Resistance Hysteresis in Oxide ReRAM: Oxygen Evolution and Reincorporation Revealed by In Situ TEM.

Science.gov (United States)

Cooper, David; Baeumer, Christoph; Bernier, Nicolas; Marchewka, Astrid; La Torre, Camilla; Dunin-Borkowski, Rafal E; Menzel, Stephan; Waser, Rainer; Dittmann, Regina

2017-06-01

The control and rational design of redox-based memristive devices, which are highly attractive candidates for next-generation nonvolatile memory and logic applications, is complicated by competing and poorly understood switching mechanisms, which can result in two coexisting resistance hystereses that have opposite voltage polarity. These competing processes can be defined as regular and anomalous resistive switching. Despite significant characterization efforts, the complex nanoscale redox processes that drive anomalous resistive switching and their implications for current transport remain poorly understood. Here, lateral and vertical mapping of O vacancy concentrations is used during the operation of such devices in situ in an aberration corrected transmission electron microscope to explain the anomalous switching mechanism. It is found that an increase (decrease) in the overall O vacancy concentration within the device after positive (negative) biasing of the Schottky-type electrode is associated with the electrocatalytic release and reincorporation of oxygen at the electrode/oxide interface and is responsible for the resistance change. This fundamental insight presents a novel perspective on resistive switching processes and opens up new technological opportunities for the implementation of memristive devices, as anomalous switching can now be suppressed selectively or used deliberately to achieve the desirable so-called deep Reset. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characteristics of tungsten oxide thin films prepared on the flexible substrates using pulsed laser deposition

International Nuclear Information System (INIS)

Suda, Yoshiaki; Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyuu, Yoshihito

2008-01-01

Tungsten trioxide (WO 3 ) thin films have been prepared on the flexible indium tin oxide (ITO) substrates by pulsed laser deposition (PLD) using WO 3 targets in oxygen gas. Color of the WO 3 film on the flexible ITO substrates depends on the oxygen gas mixture. The plasma plume produced by PLD using a Nd:YAG laser and WO 3 target is investigated by temporal and spatial-resolved optical emission spectroscopy. WO 3 films prepared on the flexible ITO substrates show electrochromic properties, even when the substrates are bent. The film color changes from blue to transparent within 10-20 s after the applied DC voltage is turned off

The oxygen effect and adaptive response of cells. Report 3. Simulation of respiratory oxygenation and oxygen permeability of cells

International Nuclear Information System (INIS)

Ehpshtejn, I.M.

1978-01-01

Variations in the oxygen concentration in extracellural [O 2 ] 0 and intracellular [Osub(2)]sub(i) media of cells small in size (d = 2 ] 0 - t-curves). It is shown that the Value of [Osub(2)]sub(i) may be expressed by four variants of its functional dependence: (a) on enzymic reaction of oxygen consumption, (b) on the order of reaction with respect to oxygen, (c) on physiological parameters of cells, and (d) on characteristic oxygen concentrations in the system. Items (c) and (d) are based on the postulated diffusion-kinetic model of oxygen consumption by an idealized cell of small size that consists of a drop of homogenous solution of the respiratory enzyme which is characterized by an equivalent Michaelis constant. The drop is enveloped in a uniform membrane that possesses a definite diffuse resistance to oxygen

Flexible All-Inorganic Perovskite CsPbBr3 Nonvolatile Memory Device.

Science.gov (United States)

Liu, Dongjue; Lin, Qiqi; Zang, Zhigang; Wang, Ming; Wangyang, Peihua; Tang, Xiaosheng; Zhou, Miao; Hu, Wei

2017-02-22

All-inorganic perovskite CsPbX 3 (X = Cl, Br, or I) is widely used in a variety of photoelectric devices such as solar cells, light-emitting diodes, lasers, and photodetectors. However, studies to understand the flexible CsPbX 3 electrical application are relatively scarce, mainly due to the limitations of the low-temperature fabricating process. In this study, all-inorganic perovskite CsPbBr 3 films were successfully fabricated at 75 °C through a two-step method. The highly crystallized films were first employed as a resistive switching layer in the Al/CsPbBr 3 /PEDOT:PSS/ITO/PET structure for flexible nonvolatile memory application. The resistive switching operations and endurance performance demonstrated the as-prepared flexible resistive random access memory devices possess reproducible and reliable memory characteristics. Electrical reliability and mechanical stability of the nonvolatile device were further tested by the robust current-voltage curves under different bending angles and consecutive flexing cycles. Moreover, a model of the formation and rupture of filaments through the CsPbBr 3 layer was proposed to explain the resistive switching effect. It is believed that this study will offer a new setting to understand and design all-inorganic perovskite materials for future stable flexible electronic devices.

Cost-effective, transfer-free, flexible resistive random access memory using laser-scribed reduced graphene oxide patterning technology.

Science.gov (United States)

Tian, He; Chen, Hong-Yu; Ren, Tian-Ling; Li, Cheng; Xue, Qing-Tang; Mohammad, Mohammad Ali; Wu, Can; Yang, Yi; Wong, H-S Philip

2014-06-11

Laser scribing is an attractive reduced graphene oxide (rGO) growth and patterning technology because the process is low-cost, time-efficient, transfer-free, and flexible. Various laser-scribed rGO (LSG) components such as capacitors, gas sensors, and strain sensors have been demonstrated. However, obstacles remain toward practical application of the technology where all the components of a system are fabricated using laser scribing. Memory components, if developed, will substantially broaden the application space of low-cost, flexible electronic systems. For the first time, a low-cost approach to fabricate resistive random access memory (ReRAM) using laser-scribed rGO as the bottom electrode is experimentally demonstrated. The one-step laser scribing technology allows transfer-free rGO synthesis directly on flexible substrates or non-flat substrates. Using this time-efficient laser-scribing technology, the patterning of a memory-array area up to 100 cm(2) can be completed in 25 min. Without requiring the photoresist coating for lithography, the surface of patterned rGO remains as clean as its pristine state. Ag/HfOx/LSG ReRAM using laser-scribing technology is fabricated in this work. Comprehensive electrical characteristics are presented including forming-free behavior, stable switching, reasonable reliability performance and potential for 2-bit storage per memory cell. The results suggest that laser-scribing technology can potentially produce more cost-effective and time-effective rGO-based circuits and systems for practical applications.

A silicon-based flexible tactile sensor for ubiquitous robot companion applications

International Nuclear Information System (INIS)

Kim, Kunnyun; Lee, Kang Ryeol; Lee, Dae Sung; Cho, Nam-Kyu; Kim, Won Hyo; Park, Kwang-Bum; Park, Hyo-Derk; Kim, Yong Kook; Park, Yon-Kyu; Kim, Jong-Ho

2006-01-01

We present the fabrication process and characteristics of a 3-axes flexible tactile sensor available for normal and shear mode fabricated using Si micromachining and packaging technologies. The fabrication processes for the 3 axes flexible tactile sensor were classified in the fabrication of sensor chips and their packaging on the flexible PCB. The variation rate of resistance was about 2.1%/N and 0.5%/N in applying normal and shear force, respectively. Because this tactile sensor can measure the variations of resistance of the semiconductor strain gauge for normal and shear force, it can be used to sense touch, pressure, hardness, and slip

Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

Energy Technology Data Exchange (ETDEWEB)

Shvets, Petr, E-mail: pshvets@innopark.kantiana.ru; Maksimova, Ksenia; Demin, Maxim; Dikaya, Olga; Goikhman, Alexander

2017-05-15

The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

Complete Healing of the Diabetic Ulcerative Osteomyelitis with Atherectomy and Flexible Stent

Directory of Open Access Journals (Sweden)

Veysel Temizkan

2014-06-01

Full Text Available Diabetes mellitus is a chronic disease that causes arterial and neurological disorders. Extremities threatening a diabetic foot ulcer might occur in the long term, especially in irregular glycemia levels. A multidisciplinary approach including infection treatment, pressure relief in the wound and arterial revascularization is important for limb salvage and to prevent such life-threatening complications as septicemia. Compared to the surgery, endovascular procedures can be performed with low complication rates in diabetic foot ulcers complicated with infection. Atherectomy is an alternative to the classical percutaneous angioplasty techniques, especially in totally occluded lesions. We are reporting complete healing of osteomyelitis associated with critical limb ischemia, resistant to classical treatment with debridement, antibacterial therapy and hyperbaric oxygen therapy, by atherectomy following long-segment flexible stent implantation. [Arch Clin Exp Surg 2014; 3(3.000: 193-196

Ovarian tumor-initiating cells display a flexible metabolism

International Nuclear Information System (INIS)

Anderson, Angela S.; Roberts, Paul C.; Frisard, Madlyn I.; Hulver, Matthew W.; Schmelz, Eva M.

2014-01-01

An altered metabolism during ovarian cancer progression allows for increased macromolecular synthesis and unrestrained growth. However, the metabolic phenotype of cancer stem or tumor-initiating cells, small tumor cell populations that are able to recapitulate the original tumor, has not been well characterized. In the present study, we compared the metabolic phenotype of the stem cell enriched cell variant, MOSE-L FFLv (TIC), derived from mouse ovarian surface epithelial (MOSE) cells, to their parental (MOSE-L) and benign precursor (MOSE-E) cells. TICs exhibit a decrease in glucose and fatty acid oxidation with a concomitant increase in lactate secretion. In contrast to MOSE-L cells, TICs can increase their rate of glycolysis to overcome the inhibition of ATP synthase by oligomycin and can increase their oxygen consumption rate to maintain proton motive force when uncoupled, similar to the benign MOSE-E cells. TICs have an increased survival rate under limiting conditions as well as an increased survival rate when treated with AICAR, but exhibit a higher sensitivity to metformin than MOSE-E and MOSE-L cells. Together, our data show that TICs have a distinct metabolic profile that may render them flexible to adapt to the specific conditions of their microenvironment. By better understanding their metabolic phenotype and external environmental conditions that support their survival, treatment interventions can be designed to extend current therapy regimens to eradicate TICs. - Highlights: • Ovarian cancer TICs exhibit a decreased glucose and fatty acid oxidation. • TICs are more glycolytic and have highly active mitochondria. • TICs are more resistant to AICAR but not metformin. • A flexible metabolism allows TICs to adapt to their microenvironment. • This flexibility requires development of specific drugs targeting TIC-specific changes to prevent recurrent TIC outgrowth

Ovarian tumor-initiating cells display a flexible metabolism

Energy Technology Data Exchange (ETDEWEB)

Anderson, Angela S. [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Roberts, Paul C. [Biomedical Science and Pathobiology, Virginia Tech, Blacksburg, VA (United States); Frisard, Madlyn I. [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Hulver, Matthew W., E-mail: hulvermw@vt.edu [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Schmelz, Eva M., E-mail: eschmelz@vt.edu [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States)

2014-10-15

An altered metabolism during ovarian cancer progression allows for increased macromolecular synthesis and unrestrained growth. However, the metabolic phenotype of cancer stem or tumor-initiating cells, small tumor cell populations that are able to recapitulate the original tumor, has not been well characterized. In the present study, we compared the metabolic phenotype of the stem cell enriched cell variant, MOSE-L{sub FFLv} (TIC), derived from mouse ovarian surface epithelial (MOSE) cells, to their parental (MOSE-L) and benign precursor (MOSE-E) cells. TICs exhibit a decrease in glucose and fatty acid oxidation with a concomitant increase in lactate secretion. In contrast to MOSE-L cells, TICs can increase their rate of glycolysis to overcome the inhibition of ATP synthase by oligomycin and can increase their oxygen consumption rate to maintain proton motive force when uncoupled, similar to the benign MOSE-E cells. TICs have an increased survival rate under limiting conditions as well as an increased survival rate when treated with AICAR, but exhibit a higher sensitivity to metformin than MOSE-E and MOSE-L cells. Together, our data show that TICs have a distinct metabolic profile that may render them flexible to adapt to the specific conditions of their microenvironment. By better understanding their metabolic phenotype and external environmental conditions that support their survival, treatment interventions can be designed to extend current therapy regimens to eradicate TICs. - Highlights: • Ovarian cancer TICs exhibit a decreased glucose and fatty acid oxidation. • TICs are more glycolytic and have highly active mitochondria. • TICs are more resistant to AICAR but not metformin. • A flexible metabolism allows TICs to adapt to their microenvironment. • This flexibility requires development of specific drugs targeting TIC-specific changes to prevent recurrent TIC outgrowth.

Oxygen-doped zirconium nitride based transparent resistive random access memory devices fabricated by radio frequency sputtering method

International Nuclear Information System (INIS)

Kim, Hee-Dong; Yun, Min Ju; Kim, Kyeong Heon; Kim, Sungho

2016-01-01

In this work, we present a feasibility of bipolar resistive switching (RS) characteristics for Oxygen-doped zirconium nitride (O-doped ZrN_x) films, produced by sputtering method, which shows a high optical transmittance of approximately 78% in the visible region as well as near ultra-violet region. In addition, in a RS test, the device has a large current ratio of 5 × 10"3 in positive bias region and 5 × 10"5 in negative bias region. Then, to evaluate an ability of data storage for the proposed memory devices, we measured a retention time for 10"4 s at room temperature (RT) and 85 °C as well. As a result, the set and reset states were stably maintained with a current ratio of ∼10"2 at 85 °C to ∼10"3 at RT. This result means that the transparent memory by controlling the working pressure during sputtering process to deposit the ZrN_x films could be a milestone for future see-through electronic devices. - Highlights: • The resistive switching characteristics of the transparent O-doped ZrN_x-based RRAM cells have investigated. • Oxygen doping concentration within ZrN_x is optimized using working pressure of sputter. • Long retention time were observed.

Flexible Al-doped ZnO films grown on PET substrates using linear facing target sputtering for flexible OLEDs

International Nuclear Information System (INIS)

Jeong, Jin-A; Shin, Hyun-Su; Choi, Kwang-Hyuk; Kim, Han-Ki

2010-01-01

We report the characteristics of flexible Al-doped zinc oxide (AZO) films prepared by a plasma damage-free linear facing target sputtering (LFTS) system on PET substrates for use as a flexible transparent conducting electrode in flexible organic light-emitting diodes (OLEDs). The electrical, optical and structural properties of LFTS-grown flexible AZO electrodes were investigated as a function of dc power. We obtained a flexible AZO film with a sheet resistance of 39 Ω/□ and an average transmittance of 84.86% in the visible range although it was sputtered at room temperature without activation of the Al dopant. Due to the effective confinement of the high-density plasma between the facing AZO targets, the AZO film was deposited on the PET substrate without plasma damage and substrate heating caused by bombardment of energy particles. Moreover, the flexible OLED fabricated on the AZO/PET substrate showed performance similar to the OLED fabricated on a ITO/PET substrate in spite of a lower work function. This indicates that LFTS is a promising plasma damage-free and low-temperature sputtering technique for deposition of flexible and indium-free AZO electrodes for use in cost-efficient flexible OLEDs.

Highly transparent vanadium oxide-graded indium zinc oxide electrodes for flexible organic solar cells

International Nuclear Information System (INIS)

Ko, Eun-Hye; Kim, Han-Ki

2016-01-01

We investigated characteristics of amorphous V_2O_5-graded InZnO (IZO) films to use as a flexible anode for flexible organic solar cells (FOSCs). Graded sputtering of the V_2O_5 layer on the IZO layer produced V_2O_5-graded IZO anodes (VGIZO) with a sheet resistance of 42.14 Ω/square, a resistivity of 6.32 × 10"−"4 Ω cm, and an optical transmittance of 82.15%, as well as good mechanical flexibility. In addition, the VGIZO electrode showed a greater work function of 5.2 eV than that (4.9 eV) of an IZO anode, which is beneficial for hole extraction from an organic active layer. Due to the higher work function of the VGIZO electrodes, FOSCs fabricated on the flexible VGIZO anode exhibited a higher power conversion efficiency 2.753% than that of FOSCs on the IZO anode. This indicates that the V_2O_5 graded sputtering is a promising technique to increase the work function of the IZO anode without change in sheet resistance and transmittance. - Highlights: • Transparent and flexible V_2O_5 graded IZO (VGIZO) electrodes. • High work function of VGIZO electrodes • The VGIZO film is a promising flexible anode for flexible organic solar cells.

Piezoresistive effect observed in flexible amorphous carbon films

Science.gov (United States)

Wang, B.; Jiang, Y. C.; Zhao, R.; Liu, G. Z.; He, A. P.; Gao, J.

2018-05-01

Amorphous carbon (a-C) films, deposited on Si substrates at 500 °C, were transferred onto flexible polyethylene (PE) substrates by a lift-off method, which overcomes the limit of deposition temperature. After transferring, a-C films exhibited a large piezoresistive effect. Such flexible samples could detect the change of bending angle by attaching them onto Cu foils. The ratio of the bending and non-bending resistances reaches as large as ~27.8, which indicates a potential application as a pressure sensor. Also, the a-C/PE sample revealed an enhanced sensitivity to gas pressure compared with the a-C/Si one. By controlling the bending angle, the sensitivity range can be tuned to shift to a low- or high-pressure region. The fatigue test shows a less than 1% change in resistance after 10 000 bending cycles. Our work provides a route to prepare the flexible and piezoresistive carbon-based devices with high sensitivity, controllable pressure-sensing and high stability.

The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

Science.gov (United States)

Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

2008-01-01

Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

Flexible Graphene Transistor Architecture for Optical Sensor Technology

Science.gov (United States)

Ordonez, Richard Christopher

The unique electrical and optoelectronic properties of graphene allow tunable conductivity and broadband electromagnetic absorption that spans the ultraviolet and infrared regimes. However, in the current state-of-art graphene sensor architectures, junction resistance and doping concentration are predominant factors that affect signal strength and sensitivity. Unfortunately, graphene produces high contact resistances with standard electrode materials ( few kilo-ohms), therefore, signal is weak and large carrier concentrations are required to probe sensitivity. Moreover, the atomic thickness of graphene enables the potential for flexible electronics, but there has not been a successful graphene sensor architecture that demonstrates stable operation on flexible substrates and with minimal fabrication cost. In this study, the author explores a novel 3-terminal transistor architecture that integrates twodimensional graphene, liquid metal, and electrolytic gate dielectrics (LM-GFETs: Liquid Metal and Graphene Field-Effect Transistors ). The goal is to deliver a sensitive, flexible, and lightweight transistor architecture that will improve sensor technology and maneuverability. The reported high thermal conductivity of graphene provides potential for room-temperature thermal management without the need of thermal-electric and gas cooling systems that are standard in sensor platforms. Liquid metals provide a unique opportunity for conformal electrodes that maximize surface area contact, therefore, enable flexibility, lower contact resistance, and reduce damage to the graphene materials involved. Lastly, electrolytic gate dielectrics provide conformability and high capacitances needed for high on/off rations and electrostatic gating. Results demonstrated that with minimal fabrication steps the proposed flexible graphene transistor architecture demonstrated ambipolar current-voltage transfer characteristics that are comparable to the current state-of-the-art. An additional

Limitations of potentiometric oxygen sensors operating at low oxygen levels

DEFF Research Database (Denmark)

Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

2011-01-01

The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10......−6 bar for an inlet flow rate higher than 2 L h−1 between 600 and 800 °C. The polarisation resistance measured between 10−6 and 10−4 bar was found to be inversely proportional to the oxygen partial pressure, nearly temperature independent and inversely proportional to the inlet gas flow rate, which shows...

Flat flexible polymer heat pipes

International Nuclear Information System (INIS)

Oshman, Christopher; Li, Qian; Liew, Li-Anne; Yang, Ronggui; Bright, Victor M; Lee, Y C

2013-01-01

Flat, flexible, lightweight, polymer heat pipes (FPHP) were fabricated. The overall geometry of the heat pipe was 130 mm × 70 mm × 1.31 mm. A commercially available low-cost film composed of laminated sheets of low-density polyethylene terephthalate, aluminum and polyethylene layers was used as the casing. A triple-layer sintered copper woven mesh served as a liquid wicking structure, and water was the working fluid. A coarse nylon woven mesh provided space for vapor transport and mechanical rigidity. Thermal power ranging from 5 to 30 W was supplied to the evaporator while the device was flexed at 0°, 45° and 90°. The thermal resistance of the FPHP ranged from 1.2 to 3.0 K W −1 depending on the operating conditions while the thermal resistance for a similar-sized solid copper reference was a constant at 4.6 K W −1 . With 25 W power input, the thermal resistance of the liquid–vapor core of the FPHP was 23% of a copper reference sample with identical laminated polymer material. This work shows a promising combination of technologies that has the potential to usher in a new generation of highly flexible, lightweight, low-cost, high-performance thermal management solutions. (paper)

Fabrication and performance evaluation of flexible heat pipes for potential thermal control of foldable electronics

International Nuclear Information System (INIS)

Yang, Chao; Chang, Chao; Song, Chengyi; Shang, Wen; Wu, Jianbo; Tao, Peng; Deng, Tao

2016-01-01

Highlights: • A flexible and high-performance heat pipe is fabricated. • Bending effect on thermal performance of flexible heat pipes is evaluated. • Theoretical analysis is carried out to reveal the change of thermal resistance with bending. • Thermal control of foldable electronics with flexible heat pipes is demonstrated. - Abstract: In this work, we report the fabrication and thermal performance evaluation of flexible heat pipes prepared by using a fluororubber tube as the connector in the adiabatic section and using strong base treated hydrophilic copper meshes as the wick structure. Deionized water was chosen as working fluid and three different filling ratios (10%, 20%, and 30%) of working fluid were loaded into the heat pipe to investigate its impact on thermal performance. The fabricated heat pipes can be easily bended from 0"o to 180"o in the horizontal operation mode and demonstrated consistently low thermal resistances after repeated bending. It was found that with optimized amount of working fluid, the thermal resistance of flexible heat pipes increased with larger bending angles. Theoretical analysis reveals that bending disturbs the normal vapor flow from evaporator to condenser in the heat pipe, thus leads to increased liquid–vapor interfacial thermal resistance in the evaporator section. The flexible heat pipes have been successfully applied for thermal control of foldable electronic devices showing superior uniform heat-transfer performance.

Highly conductive and flexible color filter electrode using multilayer film structure

Science.gov (United States)

Han, Jun Hee; Kim, Dong-Young; Kim, Dohong; Choi, Kyung Cheol

2016-07-01

In this paper, a high performance flexible component that serves as a color filter and an electrode simultaneously is suggested. The suggested highly conductive and flexible color filter electrode (CFE) has a multilayer film structure composed of silver (Ag) and tungsten trioxide (WO3). The CFE maintained its color filtering capability even when the films were bent on a polyethylene terephthalate (PET) film. Low sheet resistance of the CFE was obtained using WO3 as a bridge layer that connects two Ag layers electrically. The sheet resistance was less than 2 Ω/sq. and it was negligibly changed after bending the film, confirming the flexibility of the CFE. The CFE can be easily fabricated using a thermal evaporator and is easily patterned by photolithography or a shadow mask. The proposed CFE has enormous potential for applications involving optical devices including large area devices and flexible devices.

Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

Science.gov (United States)

Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Jeong, Sung Hoon

2015-05-21

Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

Oxygen-doped zirconium nitride based transparent resistive random access memory devices fabricated by radio frequency sputtering method

Energy Technology Data Exchange (ETDEWEB)

Kim, Hee-Dong, E-mail: khd0708@sejong.ac.kr [Department of Electrical Engineering, Sejong University, Neungdong-ro 209, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Yun, Min Ju [Department of Electrical Engineering, Sejong University, Neungdong-ro 209, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Kim, Kyeong Heon [School of Electrical Engineering, Korea University, Anam-dong, Sungbuk-gu, Seoul 163-701 (Korea, Republic of); Kim, Sungho, E-mail: sungho85.kim@sejong.ac.kr [Department of Electrical Engineering, Sejong University, Neungdong-ro 209, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

2016-08-05

In this work, we present a feasibility of bipolar resistive switching (RS) characteristics for Oxygen-doped zirconium nitride (O-doped ZrN{sub x}) films, produced by sputtering method, which shows a high optical transmittance of approximately 78% in the visible region as well as near ultra-violet region. In addition, in a RS test, the device has a large current ratio of 5 × 10{sup 3} in positive bias region and 5 × 10{sup 5} in negative bias region. Then, to evaluate an ability of data storage for the proposed memory devices, we measured a retention time for 10{sup 4} s at room temperature (RT) and 85 °C as well. As a result, the set and reset states were stably maintained with a current ratio of ∼10{sup 2} at 85 °C to ∼10{sup 3} at RT. This result means that the transparent memory by controlling the working pressure during sputtering process to deposit the ZrN{sub x} films could be a milestone for future see-through electronic devices. - Highlights: • The resistive switching characteristics of the transparent O-doped ZrN{sub x}-based RRAM cells have investigated. • Oxygen doping concentration within ZrN{sub x} is optimized using working pressure of sputter. • Long retention time were observed.

Ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen

Science.gov (United States)

Janoff, Dwight; Bamford, Larry J.; Newton, Barry E.; Bryan, Coleman J.

1989-01-01

A high-volume pneumatic-impact system has been used to test PTFE-lined stainless steel braided hoses, in order to characterize the roles played in the mechanism of oxygen-induced ignition by impact pressure, pressurization rate, and upstream and downstream volumes of the hose. Ignitions are noted to have occurred at impact pressures well below the working pressure of the hoses, as well as at pressurization rates easily obtainable through manual operation of valves. The use of stainless steel hardlines downstream of the hose prevented ignitions at all pressures and pressurization rates; internal observations have shown evidence of shock ionization in the oxygen prior to ignition.

Transparent and flexible resistive switching memory devices with a very high ON/OFF ratio using gold nanoparticles embedded in a silk protein matrix

Science.gov (United States)

Gogurla, Narendar; Mondal, Suvra P.; Sinha, Arun K.; Katiyar, Ajit K.; Banerjee, Writam; Kundu, Subhas C.; Ray, Samit K.

2013-08-01

The growing demand for biomaterials for electrical and optical devices is motivated by the need to make building blocks for the next generation of printable bio-electronic devices. In this study, transparent and flexible resistive memory devices with a very high ON/OFF ratio incorporating gold nanoparticles into the Bombyx mori silk protein fibroin biopolymer are demonstrated. The novel electronic memory effect is based on filamentary switching, which leads to the occurrence of bistable states with an ON/OFF ratio larger than six orders of magnitude. The mechanism of this process is attributed to the formation of conductive filaments through silk fibroin and gold nanoparticles in the nanocomposite. The proposed hybrid bio-inorganic devices show promise for use in future flexible and transparent nanoelectronic systems.

Transparent and flexible resistive switching memory devices with a very high ON/OFF ratio using gold nanoparticles embedded in a silk protein matrix

International Nuclear Information System (INIS)

Gogurla, Narendar; Mondal, Suvra P; Sinha, Arun K; Katiyar, Ajit K; Banerjee, Writam; Ray, Samit K; Kundu, Subhas C

2013-01-01

The growing demand for biomaterials for electrical and optical devices is motivated by the need to make building blocks for the next generation of printable bio-electronic devices. In this study, transparent and flexible resistive memory devices with a very high ON/OFF ratio incorporating gold nanoparticles into the Bombyx mori silk protein fibroin biopolymer are demonstrated. The novel electronic memory effect is based on filamentary switching, which leads to the occurrence of bistable states with an ON/OFF ratio larger than six orders of magnitude. The mechanism of this process is attributed to the formation of conductive filaments through silk fibroin and gold nanoparticles in the nanocomposite. The proposed hybrid bio-inorganic devices show promise for use in future flexible and transparent nanoelectronic systems. (paper)

Free-Standing, Flexible, Superomniphobic Films.

Science.gov (United States)

Vahabi, Hamed; Wang, Wei; Movafaghi, Sanli; Kota, Arun K

2016-08-31

Fabrication of most superomniphobic surfaces requires complex process conditions or specialized and expensive equipment or skilled personnel. In order to circumvent these issues and make them end-user-friendly, we developed the free-standing, flexible, superomniphobic films. These films can be stored and delivered to the end-users, who can readily attach them to virtually any surface (even irregular shapes) and impart superomniphobicity. The hierarchical structure, the re-entrant texture, and the low solid surface energy render our films superomniphobic for a wide variety of liquids. We demonstrate that our free-standing, flexible, superomniphobic films have applications in enhanced chemical resistance and enhanced weight bearing.

Simulations of Micropumps Based on Tilted Flexible Fibers

Science.gov (United States)

Hancock, Matthew; Elabbasi, Nagi; Demirel, Melik

2015-11-01

Pumping liquids at low Reynolds numbers is challenging because of the principle of reversibility. We report here a class of microfluidic pump designs based on tilted flexible structures that combines the concepts of cilia (flexible elastic elements) and rectifiers (e.g., Tesla valves, check valves). We demonstrate proof-of-concept with 2D and 3D fluid-structure interaction (FSI) simulations in COMSOL Multiphysics®of micropumps consisting of a source for oscillatory fluidic motion, e.g. a piston, and a channel lined with tilted flexible rods or sheets to provide rectification. When flow is against the rod tilt direction, the rods bend backward, narrowing the channel and increasing flow resistance; when flow is in the direction of rod tilt, the rods bend forward, widening the channel and decreasing flow resistance. The 2D and 3D simulations involve moving meshes whose quality is maintained by prescribing the mesh displacement on guide surfaces positioned on either side of each flexible structure. The prescribed displacement depends on structure bending and maintains mesh quality even for large deformations. Simulations demonstrate effective pumping even at Reynolds numbers as low as 0.001. Because rod rigidity may be specified independently of Reynolds number, in principle, rod rigidity may be reduced to enable pumping at arbitrarily low Reynolds numbers.

Excess postexercise oxygen consumption is unaffected by the resistance and aerobic exercise order in an exercise session.

Science.gov (United States)

Oliveira, Norton L; Oliveira, Jose

2011-10-01

The main purpose of this study was to compare the magnitude and duration of excess postexercise oxygen consumption (EPOC) after 2 exercise sessions with different exercise mode orders, resistance followed by aerobic exercise (R-A); aerobic by resistance exercise (A-R). Seven young men (19.6 ± 1.4 years) randomly underwent the 2 sessions. Aerobic exercise was performed on a treadmill for 30 minutes (80-85% of reserve heart rate). Resistance exercise consisted of 3 sets of 10 repetition maximum on 5 exercises. Previous to the exercise sessions, V(O2), heart rate, V(CO2), and respiratory exchange rate (RER) were measured for 15 minutes and again during recovery from exercise for 60 minutes. The EPOC magnitude was not significantly different between R-A (5.17 ± 2.26 L) and A-R (5.23 ± 2.48 L). Throughout the recovery period (60 minutes), V(O2) and HR values were significantly higher than those observed in the pre-exercise period (p better to start a training session.

Low Power Resistive Oxygen Sensor Based on Sonochemical SrTi0.6Fe0.4O2.8 (STFO40

Directory of Open Access Journals (Sweden)

Alisa Stratulat

2015-07-01

Full Text Available The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (typical grain size of 50 nm SrTi0.6Fe0.4O2.8 (Sono-STFO40 powder. This powder is characterized using X ray-diffraction (XRD, Mössbauer spectroscopy and Scanning Electron Microscopy (SEM, and results are compared with commercially available SrTi0.4Fe0.6O2.8 (STFO60 powder. In order to manufacture resistive oxygen sensors, both Sono-STFO40 and STFO60 are deposited, by dip-pen nanolithography (DPN method, on an SOI (Silicon-on-Insulator micro-hotplate, employing a tungsten heater embedded within a dielectric membrane. Oxygen detection tests are performed in both dry (RH = 0% and humid (RH = 60% nitrogen atmosphere, varying oxygen concentrations between 1% and 16% (v/v, at a constant heater temperature of 650 °C. The oxygen sensor, based on the Sono-STFO40 sensing layer, shows good sensitivity, low power consumption (80 mW, and short response time (25 s. These performance are comparable to those exhibited by state-of-the-art O2 sensors based on STFO60, thus proving Sono-STFO40 to be a material suitable for oxygen detection in harsh environments.

ITO films realized at room-temperature by ion beam sputtering for high-performance flexible organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Lucas, B.; Rammal, W.; Moliton, A. [Limoges Univ., Faculte des Sciences et Techniques, CNRS, UMR 6172, Institut de Recherche XLIM, Dept. MINACOM, 87 - Limoges (France)

2006-06-15

Indium-tin oxide (ITO) thin layers are obtained by an IBS (Ion Beam Sputtering) deposition process. We elaborated ITO films on flexible substrates of polyethylene terephthalate (PET), under soft conditions of low temperatures and fulfilling the requirements of fabrication processes of the organic optoelectronic components. With a non thermally activated (20 Celsius degrees) ITO deposition assisted by an oxygen flow (1 cm{sup 3}/min), we got an optical transmittance of 90% in the visible range, a resistivity around 10{sup -3} {omega}.cm and a surface roughness lower than 1.5 mm. Thus we realized flexible organic light-emitting diodes (FOLEDs) with good performances: a maximum luminance of 12000 cd/m{sup 2} at a voltage of 19 V and a maximum luminous power efficiency around 1 lm/W at a voltage of 10 V (or a maximum current efficiency of 4 cd/A at 14 V) for the (PET(50 {mu}m) / ITO(200 nm) / TPD(40 nm) / Alq3(60 nm) / Ca / Al) structure. (authors)

Flexible, pre-insulated pipelines for heat and water supply. Systems with integrated quality and service; Flexible, vorgedaemmte Rohrsysteme fuer die Versorgungstechnik. Gesamtsysteme mit Qualitaet und Service

Energy Technology Data Exchange (ETDEWEB)

Hetzel, Michaela [Uponor Central Europe, Hassfurt (Germany). Unternehmenskommunikation

2010-10-15

Flexible pipes are suited for heat distribution, cooling water and freshwater transport. Uponor uses a modified, cross-linked polythene for insulation. The material is flexible, ageing-resistant, and will reduce the heat loss. Pipes are supplied to the construction site within two days, cut to measure and with all required parts. (orig.)

Resistive switching in Pt/TiO{sub 2}/Pt

Energy Technology Data Exchange (ETDEWEB)

Jeong, Doo Seok

2008-08-15

Recently, the resistive switching behavior in TiO{sub 2} has drawn attention due to its application to resistive random access memory (RRAM) devices. TiO{sub 2} shows characteristic non-volatile resistive switching behavior, i.e. reversible switching between a high resistance state (HRS) and a low resistance state (LRS). Both unipolar resistive switching (URS) and bipolar resistive switching (BRS) are found to be observed in TiO{sub 2} depending on the compliance current for the electroforming. In this thesis the characteristic current-voltage (I-V) hysteresis in three different states of TiO{sub 2}, pristine, URS-activated, and BRS-activated states, was investigated and understood in terms of the migration of oxygen vacancies in TiO{sub 2}. The I-V hysteresis of pristine TiO{sub 2} was found to show volatile behavior. That is, the temporary variation of the resistance took place depending on the applied voltage. However, the I-V hysteresis of URS- and BRS-activated states showed non-volatile resistive switching behavior. Some evidences proving the evolution of oxygen gas during electroforming were obtained from time-of-flight secondary ion mass spectroscopy analysis and the variation of the morphology of switching cells induced by the electroforming. On the assumption that a large number of oxygen vacancies are introduced by the electroforming process, the I-V behavior in electroformed switching cells was simulated with varying the distribution of oxygen vacancies in electroformed TiO{sub x} (x oxygen formation/annihilation reactions at a Pt/TiO{sub x} interface. The oxygen-related reactions given as a function of the applied voltage affect the distribution of oxygen vacancies in TiO{sub x}, consequently, the Schottky barrier height at the cathode/TiO{sub x} interface is influenced by the oxygen vacancy distribution. Therefore, the BRS behavior including the

Scalable transfer of vertical graphene nanosheets for flexible supercapacitor applications

Science.gov (United States)

Sahoo, Gopinath; Ghosh, Subrata; Polaki, S. R.; Mathews, Tom; Kamruddin, M.

2017-10-01

Vertical graphene nanosheets (VGN) are the material of choice for application in next-generation electronic devices. The growing demand for VGN-based flexible devices for the electronics industry brings in restriction on VGN growth temperature. The difficulty associated with the direct growth of VGN on flexible substrates can be overcome by adopting an effective strategy of transferring the well-grown VGN onto arbitrary flexible substrates through a soft chemistry route. In the present study, we report an inexpensive and scalable technique for the polymer-free transfer of VGN onto arbitrary substrates without disrupting its morphology, structure, and properties. After transfer, the morphology, chemical structure, and electrical properties are analyzed by scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and four-probe resistive methods, respectively. The wetting properties are studied from the water contact angle measurements. The observed results indicate the retention of morphology, surface chemistry, structure, and electronic properties. Furthermore, the storage capacity of the transferred VGN-based binder-free and current collector-free flexible symmetric supercapacitor device is studied. A very low sheet resistance of 670 Ω/□ and excellent supercapacitance of 158 μF cm-2 with 86% retention after 10 000 cycles show the prospect of the damage-free VGN transfer approach for the fabrication of flexible nanoelectronic devices.

Cathodic protection beneath thick external coating on flexible pipeline

Energy Technology Data Exchange (ETDEWEB)

Festy, Dominique; Choqueuse, Dominique; Leflour, Denise; Lepage, Vincent [Ifremer - Centre de Brest, BP 70 29280 Plouzane (France); Condat, Carol Taravel; Desamais, Nicolas [Technip- FLEXIFRANCE - PED/PEC - Rue Jean Hure, 76580 Le Trait (France); Tribollet, Bernard [UPR 15 du CNRS, Laboratoire LISE, 4 Place Jussieu, 75252 Paris Cedex (France)

2004-07-01

Flexible offshore pipelines possess an external polymer sheath to protect the structure against seawater. In case of an accidental damage of the outer sheath, the annulus of the flexible pipe is flooded with seawater. Far from the damage, corrosion and/or corrosion fatigue of armour steel wires in the annulus occur in a strictly deaerated environment; this has been studied for a few years. At the damage location, the steel wires are in direct contact with renewed seawater. In order to protect them against corrosion, a cathodic protection is applied using sacrificial anodes located at the end fittings. The goal of this work is to evaluate the extent of the cathodic protection as well as the electrolyte oxygen concentration beneath the coating around the damage, to know whether or not there is a non protected area with enough oxygen where corrosion and corrosion fatigue can occur. The experimental work was performed with a model cell (2000 x 200 mm{sup 2}), composed of a mild steel plate and a PMMA coat (transparent poly-methyl-methacrylate). The thickness of the gap between the steel plate and the PMMA coat was 0.5 mm. The potential and current density were monitored all along the cell (70 sensors). The oxygen concentration was also recorded. The experiments were performed with natural sea water, and cathodic protection was applied in a reservoir at one extremity of the cell. Another reservoir at the other cell extremity enabled carbon dioxide bubbling to simulate pipeline annular conditions. PROCOR software was used to simulate potential and current density within the gap and a mathematical model was developed to model oxygen concentration evolution. Both model and experimental results show that the extent of the cathodic protection is much greater than that of oxygen. Oxygen depletion is very quick within the gap when seawater fills it and the oxygen concentration is close to zero a few milli-metres from the gap opening. On the other hand, the cathodic protection

Polymer-metal hybrid transparent electrodes for flexible electronics

Science.gov (United States)

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 95% and a sheet resistance 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.

Optic nerve oxygenation

DEFF Research Database (Denmark)

Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

2005-01-01

The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

Effects of oxygen gas flow rate and ion beam plasma conditions on the opto-electronic properties of indium molybdenum oxide films fabricated by ion beam-assisted evaporation

International Nuclear Information System (INIS)

Kuo, C.C.; Liu, C.C.; Lin, C.C.; Liou, Y.Y.; He, J.L.; Chen, F.S.

2008-01-01

The purpose of the present work is to experimentally study the effects of the oxygen gas flow rate and ion beam plasma conditions on the properties of indium molybdenum oxide (IMO) films deposited onto the polyethersulfone (PES) substrate. Crystal structure, surface morphology, and optoelectronic properties of IMO films are examined as a function of oxygen gas flow rate and ion beam discharge voltage. Experimental results show that the IMO films consist of a cubic bixbyite B-In 2 O 3 single phase with its crystal preferred orientation alone B(222). Mo 6+ ions are therefore considered to partially substitute In 3+ sites in the deposit. Under-controlled ion bombardment during deposition enhances the reaction among those arriving oxygen and metal ion species to condense into IMO film and facilitates a decreased surface roughness of IMO film. The film with ultimate crystallinity and the lowest surface roughness is obtained when the oxygen flow rate of 3 sccm and the discharge voltage of 110 V are employed. This results in the lowest electrical resistivity due mainly to the increased Hall mobility and irrelevant to carrier concentration. The lowest electrical resistivity of 8.63 x 10 -4 ohm-cm with a 84.63% transmittance at a wavelength of 550 nm can be obtained, which satisfies the requirement of a flexible transparent conductive polymer substrate

Kinetics of oxygen uncoupling of a copper based oxygen carrier

International Nuclear Information System (INIS)

Hu, Wenting; Donat, Felix; Scott, S.A.; Dennis, J.S.

2016-01-01

Highlights: • The kinetics of a Cu-based oxygen carrier was determined using a TGA. • A diffusion model was applied to remove mass transfer effects from rate parameters. • Thermodynamics are separated from kinetics, usually difficult for the CLOU reaction. • The rate parameters correctly described the behaviour in a fluidised bed. • The rate parameters can be used to predict performance of large CLOU systems. - Abstract: Here, an oxygen carrier consisting of 60 wt% CuO supported on a mixture of Al_2O_3 and CaO (23 wt% and 17 wt% respectively) was synthesised by wet-mixing powdered CuO, Al(OH)_3 and Ca(OH)_2, followed by calcination at 1000 °C. Its suitability for chemical looping with oxygen uncoupling (CLOU) was investigated. After 25 repeated redox cycles in either a thermogravimetric analyser (TGA) or a laboratory-scale fluidised bed, (with 5 vol% H_2 in N_2 as the fuel, and air as the oxidant) no significant change in either the oxygen uncoupling capacity or the overall oxygen availability of the carrier was found. In the TGA, it was found that the rate of oxygen release from the material was controlled by intrinsic chemical kinetics and external transfer of mass from the surface of the particles to the bulk gas. By modelling the various resistances, values of the rate constant for the decomposition were obtained. The activation energy of the reaction was found to be 59.7 kJ/mol (with a standard error of 5.6 kJ/mol) and the corresponding pre-exponential factor was 632 m"3/mol/s. The local rate of conversion within a particle was assumed to occur either (i) by homogeneous chemical reaction, or (ii) in uniform, non-porous grains, each reacting as a kinetically-controlled shrinking core. Upon cross validation against a batch fluidised bed experiment, the homogeneous reaction model was found to be more plausible. By accurately accounting for the various artefacts (e.g. mass transfer resistances) present in both TGA and fluidised bed experiments, it was

Macroscopic results for a novel oxygenated silicon material

International Nuclear Information System (INIS)

Watts, S.J.; Da Via', C.; Karpenko, A.

2002-01-01

High-resistivity FZ silicon diodes have been processed in order to increase their oxygen dimer (O 2i ) concentration. Deep level transient spectroscopy measurements have been performed after proton irradiation showing that the formation of the VO centre is suppressed. The substrates had a starting resistivity of 2-4 kΩ cm, with an oxygen concentration of 10 15 and 10 17 cm -3 . Results for doping changes, leakage current and annealing behaviour after irradiation with 24 GeV/c protons are shown

Flexible pressure sensors for smart protective clothing against impact loading

International Nuclear Information System (INIS)

Wang, Fei; Zhu, Bo; Shu, Lin; Tao, Xiaoming

2014-01-01

The development of smart protective clothing will facilitate the quick detection of injuries from contact sports, traffic collisions and other accidents. To obtain real-time information like spatial and temporal pressure distributions on the clothing, flexible pressure sensor arrays are required. Based on a resistive fabric strain sensor we demonstrate all flexible, resistive pressure sensors with a large workable pressure range (0–8 MPa), a high sensitivity (1 MPa −1 ) and an excellent repeatability (lowest non-repeatability ±2.4% from 0.8 to 8 MPa) that can be inexpensively fabricated using fabric strain sensors and biocompatible polydimethylsiloxane (PDMS). The pressure sensitivity is tunable by using elastomers with different elasticities or by the pre-strain control of fabric strain sensors. Finite element simulation further confirms the sensor design. The simple structure, large workable pressure range, high sensitivity, high flexibility, facile fabrication and low cost of these pressure sensors make them promising candidates for smart protective clothing against impact loading. (paper)

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Yunxia Gao

Full Text Available 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 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. 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 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. 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 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

Resistance-Based Ceramic Ho123 Ionic Conductor for Oxygen Gas Sensing

Science.gov (United States)

Idrus, L. H.; Yahya, A. K.

2009-07-01

Oxygen sensing properties of HoBa2Cu3O7-δ ceramic rods utilizing hot-spot phenomenon have been characterized. The rods were prepared from high purity oxides using the conventional solid-state reaction method. I-V characterization showed increase in output current with voltage before the appearance of the hot spot. After the appearance of the hot-spot, the output current strongly depended on oxygen partial pressure. The rod showed stable sensing characteristics with good electrical stability and reproducibility with higher sensitivity at low oxygen partial pressure. The sensing property is associated with the absorption of oxygen and dissociation into holes and oxide ions. Ho123 is more sensitive at pO2 below 20% compared to Er123 possibly due to differences in oxygen activation energy related to RE ionic radius.

Resistance-Based Ceramic Ho123 Ionic Conductor for Oxygen Gas Sensing

International Nuclear Information System (INIS)

Idrus, L. H.; Yahya, A. K.

2009-01-01

Oxygen sensing properties of HoBa 2 Cu 3 O 7-δ ceramic rods utilizing hot-spot phenomenon have been characterized. The rods were prepared from high purity oxides using the conventional solid-state reaction method. I-V characterization showed increase in output current with voltage before the appearance of the hot spot. After the appearance of the hot-spot, the output current strongly depended on oxygen partial pressure. The rod showed stable sensing characteristics with good electrical stability and reproducibility with higher sensitivity at low oxygen partial pressure. The sensing property is associated with the absorption of oxygen and dissociation into holes and oxide ions. Ho123 is more sensitive at pO 2 below 20% compared to Er123 possibly due to differences in oxygen activation energy related to RE ionic radius.

Iron-niobium-aluminum alloy having high-temperature corrosion resistance

Science.gov (United States)

Hsu, Huey S.

1988-04-14

An alloy for use in high temperature sulfur and oxygen containing environments, having aluminum for oxygen resistance, niobium for sulfur resistance and the balance iron, is discussed. 4 figs., 2 tabs.

Influence of oxygen on NADH recycling and oxidative stress resistance systems in Lactobacillus panis PM1.

Science.gov (United States)

Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

2013-01-31

Lactobacillus panis strain PM1 is an obligatory heterofermentative and aerotolerant microorganism that also produces 1,3-propanediol from glycerol. This study investigated the metabolic responses of L. panis PM1 to oxidative stress under aerobic conditions. Growth under aerobic culture triggered an early entrance of L. panis PM1 into the stationary phase along with marked changes in end-product profiles. A ten-fold higher concentration of hydrogen peroxide was accumulated during aerobic culture compared to microaerobic culture. This H2O2 level was sufficient for the complete inhibition of L. panis PM1 cell growth, along with a significant reduction in end-products typically found during anaerobic growth. In silico analysis revealed that L. panis possessed two genes for NADH oxidase and NADH peroxidase, but their expression levels were not significantly affected by the presence of oxygen. Specific activities for these two enzymes were observed in crude extracts from L. panis PM1. Enzyme assays demonstrated that the majority of the H2O2 in the culture media was the product of NADH: H2O2 oxidase which was constitutively-active under both aerobic and microaerobic conditions; whereas, NADH peroxidase was positively-activated by the presence of oxygen and had a long induction time in contrast to NADH oxidase. These observations indicated that a coupled NADH oxidase - NADH peroxidase system was the main oxidative stress resistance mechanism in L. panis PM1, and was regulated by oxygen availability. Under aerobic conditions, NADH is mainly reoxidized by the NADH oxidase - peroxidase system rather than through the production of ethanol (or 1,3-propanediol or succinic acid production if glycerol or citric acid is available). This system helped L. panis PM1 directly use oxygen in its energy metabolism by producing extra ATP in contrast to homofermentative lactobacilli.

Resistive switching effect in the planar structure of all-printed, flexible and rewritable memory device based on advanced 2D nanocomposite of graphene quantum dots and white graphene flakes

International Nuclear Information System (INIS)

Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Kim, Sowon; Choi, Kyung Hyun

2017-01-01

Pursuit of the most appropriate materials and fabrication methods is essential for developing a reliable, rewritable and flexible memory device. In this study, we have proposed an advanced 2D nanocomposite of white graphene (hBN) flakes embedded with graphene quantum dots (GQDs) as the functional layer of a flexible memory device owing to their unique electrical, chemical and mechanical properties. Unlike the typical sandwich type structure of a memory device, we developed a cost effective planar structure, to simplify device fabrication and prevent sneak current. The entire device fabrication was carried out using printing technology followed by encapsulation in an atomically thin layer of aluminum oxide (Al 2 O 3 ) for protection against environmental humidity. The proposed memory device exhibited attractive bipolar switching characteristics of high switching ratio, large electrical endurance and enhanced lifetime, without any crosstalk between adjacent memory cells. The as-fabricated device showed excellent durability for several bending cycles at various bending diameters without any degradation in bistable resistive states. The memory mechanism was deduced to be conductive filamentary; this was validated by illustrating the temperature dependence of bistable resistive states. Our obtained results pave the way for the execution of promising 2D material based next generation flexible and non-volatile memory (NVM) applications. (paper)

Scalable Coating and Properties of Transparent, Flexible, Silver Nanowire Electrodes

KAUST Repository

Hu, Liangbing

2010-05-25

We report a comprehensive study of transparent and conductive silver nanowire (Ag NW) electrodes, including a scalable fabrication process, morphologies, and optical, mechanical adhesion, and flexibility properties, and various routes to improve the performance. We utilized a synthesis specifically designed for long and thin wires for improved performance in terms of sheet resistance and optical transmittance. Twenty Ω/sq and ∼ 80% specular transmittance, and 8 ohms/sq and 80% diffusive transmittance in the visible range are achieved, which fall in the same range as the best indium tin oxide (ITO) samples on plastic substrates for flexible electronics and solar cells. The Ag NW electrodes show optical transparencies superior to ITO for near-infrared wavelengths (2-fold higher transmission). Owing to light scattering effects, the Ag NW network has the largest difference between diffusive transmittance and specular transmittance when compared with ITO and carbon nanotube electrodes, a property which could greatly enhance solar cell performance. A mechanical study shows that Ag NW electrodes on flexible substrates show excellent robustness when subjected to bending. We also study the electrical conductance of Ag nanowires and their junctions and report a facile electrochemical method for a Au coating to reduce the wire-to-wire junction resistance for better overall film conductance. Simple mechanical pressing was also found to increase the NW film conductance due to the reduction of junction resistance. The overall properties of transparent Ag NW electrodes meet the requirements of transparent electrodes for many applications and could be an immediate ITO replacement for flexible electronics and solar cells. © 2010 American Chemical Society.

Scalable Coating and Properties of Transparent, Flexible, Silver Nanowire Electrodes

KAUST Repository

Hu, Liangbing; Kim, Han Sun; Lee, Jung-Yong; Peumans, Peter; Cui, Yi

2010-01-01

We report a comprehensive study of transparent and conductive silver nanowire (Ag NW) electrodes, including a scalable fabrication process, morphologies, and optical, mechanical adhesion, and flexibility properties, and various routes to improve the performance. We utilized a synthesis specifically designed for long and thin wires for improved performance in terms of sheet resistance and optical transmittance. Twenty Ω/sq and ∼ 80% specular transmittance, and 8 ohms/sq and 80% diffusive transmittance in the visible range are achieved, which fall in the same range as the best indium tin oxide (ITO) samples on plastic substrates for flexible electronics and solar cells. The Ag NW electrodes show optical transparencies superior to ITO for near-infrared wavelengths (2-fold higher transmission). Owing to light scattering effects, the Ag NW network has the largest difference between diffusive transmittance and specular transmittance when compared with ITO and carbon nanotube electrodes, a property which could greatly enhance solar cell performance. A mechanical study shows that Ag NW electrodes on flexible substrates show excellent robustness when subjected to bending. We also study the electrical conductance of Ag nanowires and their junctions and report a facile electrochemical method for a Au coating to reduce the wire-to-wire junction resistance for better overall film conductance. Simple mechanical pressing was also found to increase the NW film conductance due to the reduction of junction resistance. The overall properties of transparent Ag NW electrodes meet the requirements of transparent electrodes for many applications and could be an immediate ITO replacement for flexible electronics and solar cells. © 2010 American Chemical Society.

Electromechanical properties of indium–tin–oxide/poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) hybrid electrodes for flexible transparent electrodes

International Nuclear Information System (INIS)

Jung, Sunghoon; Lim, Kyounga; Kang, Jae-Wook; Kim, Jong-Kuk; Oh, Se-In; Eun, Kyoungtae; Kim, Do-Geun; Choa, Sung-Hoon

2014-01-01

We investigated an indium–tin–oxide (ITO)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hybrid electrode as a potential flexible and transparent electrode. In particular, the mechanical integrity of an ITO/PEDOT:PSS hybrid electrode deposited onto a polyethylene terephthalate (PET) substrate was investigated via outer/inner bending, twisting, stretching, and adhesion tests. A PEDOT:PSS layer was inserted between ITO and PET substrate as a buffer layer to improve the flexibility and electrical properties. When a PEDOT:PSS layer was inserted, the sheet resistance of the 20 nm-thick ITO film decreased from 270 Ω/square to 57 Ω/square. Notably, the ITO/PEDOT:PSS hybrid electrode had a constant resistance change (ΔR/R 0 ) within an outer and inner bending radius of 3 mm. The bending fatigue test showed that the ITO/PEDOT:PSS hybrid electrode can withstand 10,000 bending cycles. Furthermore, the stretched ITO/PEDOT:PSS hybrid electrode showed a fairly constant resistance change up to 4%, which is more stable than the resistance change of the ITO electrode. The ITO/PEDOT:PSS electrode also shows good adhesion strength. The superior flexibility of the ITO/PEDOT:PSS hybrid electrode is attributed to the existence of a flexible PEDOT:PSS layer. This indicates that the hybridization of an ITO and PEDOT:PSS layer is a promising electrode scheme for next-generation flexible transparent electrodes. - Highlights: • We propose a hybrid electrode for flexible electronics. • Electrode made from In 2 O 3 :SnO 2 /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) • PEDOT:PSS as a buffer layer increases flexibility and electrical conductivity. • Hybrid electrode has a superior flexibility. • Hybrid electrode can be a promising flexible transparent electrode scheme

Microfluidic Device to Measure the Speed of C. elegans Using the Resistance Change of the Flexible Electrode

Directory of Open Access Journals (Sweden)

Jaehoon Jung

2016-03-01

Full Text Available This work presents a novel method to assess the condition of Caenorhabditis elegans (C. elegans through a resistance measurement of its undulatory locomotion speed inside a micro channel. As the worm moves over the electrode inside the micro channel, the length of the electrode changes, consequently behaving like a strain gauge. In this paper, the electrotaxis was applied for controlling the direction of motion of C. elegans as an external stimulus, resulting in the worm moving towards the cathode of the circuit. To confirm the proposed measurement method, a microfluidic device was developed that employs a sinusoidal channel and a thin polydimethylsiloxane (PDMS layer with an electrode. The PDMS layer maintains a porous structure to enable the flexibility of the electrode. In this study, 6 measurements were performed to obtain the speed of an early adult stage C. elegans, where the measured average speed was 0.35 (±0.05 mm/s. The results of this work demonstrate the application of our method to measure the speed of C. elegans undulatory locomotion. This novel approach can be applied to make such measurements without an imaging system, and more importantly, allows directly to detect the locomotion of C. elegans using an electrical signal (i.e., the change in resistance.

Propulsion via flexible flapping in granular media

Science.gov (United States)

Peng, Zhiwei; Ding, Yang; Pietrzyk, Kyle; Elfring, Gwynn; Pak, On Shun

2017-11-01

Biological locomotion in nature is often achieved by the interaction between a flexible body and its surrounding medium. The interaction of a flexible body with granular media is less understood compared with viscous fluids partially due to its complex rheological properties. In this work, we explore the effect of flexibility on granular propulsion by considering a simple mechanical model in which a rigid rod is connected to a torsional spring that is under a displacement actuation using a granular resistive force theory. Through a combined numerical and asymptotic investigation, we characterize the propulsive dynamics of such a flexible flapper in relation to the actuation amplitude and spring stiffness, and we compare these dynamics with those observed in a viscous fluid. In addition, we demonstrate that the maximum possible propulsive force can be obtained in the steady propulsion limit with a finite spring stiffness and large actuation amplitude. These results may apply to the development of synthetic locomotive systems that exploit flexibility to move through complex terrestrial media. Funding for Z.P. and Y.D. was partially provided by NSFC 394 Grant No. 11672029 and NSAF-NSFC Grant No. U1530401.

Wind-Induced Reconfigurations in Flexible Branched Trees

Science.gov (United States)

Ojo, Oluwafemi; Shoele, Kourosh

2017-11-01

Wind induced stresses are the major mechanical cause of failure in trees. We know that the branching mechanism has an important effect on the stress distribution and stability of a tree in the wind. Eloy in PRL 2011, showed that Leonardo da Vinci's original observation which states the total cross section of branches is conserved across branching nodes is the best configuration for resisting wind-induced fracture in rigid trees. However, prediction of the fracture risk and pattern of a tree is also a function of their reconfiguration capabilities and how they mitigate large wind-induced stresses. In this studies through developing an efficient numerical simulation of flexible branched trees, we explore the role of the tree flexibility on the optimal branching. Our results show that the probability of a tree breaking at any point depends on both the cross-section changes in the branching nodes and the level of tree flexibility. It is found that the branching mechanism based on Leonardo da Vinci's original observation leads to a uniform stress distribution over a wide range of flexibilities but the pattern changes for more flexible systems.

The Conductive Silver Nanowires Fabricated by Two-beam Laser Direct Writing on the Flexible Sheet

Science.gov (United States)

He, Gui-Cang; Zheng, Mei-Ling; Dong, Xian-Zi; Jin, Feng; Liu, Jie; Duan, Xuan-Ming; Zhao, Zhen-Sheng

2017-02-01

Flexible electrically conductive nanowires are now a key component in the fields of flexible devices. The achievement of metal nanowire with good flexibility, conductivity, compact and smooth morphology is recognized as one critical milestone for the flexible devices. In this study, a two-beam laser direct writing system is designed to fabricate AgNW on PET sheet. The minimum width of the AgNW fabricated by this method is 187 ± 34 nm with the height of 84 ± 4 nm. We have investigated the electrical resistance under different voltages and the applicable voltage per meter range is determined to be less than 7.5 × 103 V/m for the fabricated AgNW. The flexibility of the AgNW is very excellent, since the resistance only increases 6.63% even after the stretched bending of 2000 times at such a small bending radius of 1.0 mm. The proposed two-beam laser direct writing is an efficient method to fabricate AgNW on the flexible sheet, which could be applied in flexible micro/nano devices.

Macroscopic results for a novel oxygenated silicon material

CERN Document Server

Watts, S J; Karpenko, A

2002-01-01

High-resistivity FZ silicon diodes have been processed in order to increase their oxygen dimer (O sub 2 sub i) concentration. Deep level transient spectroscopy measurements have been performed after proton irradiation showing that the formation of the VO centre is suppressed. The substrates had a starting resistivity of 2-4 k OMEGA cm, with an oxygen concentration of 10 sup 1 sup 5 and 10 sup 1 sup 7 cm sup - sup 3. Results for doping changes, leakage current and annealing behaviour after irradiation with 24 GeV/c protons are shown.

Monitoring of Vital Signs with Flexible and Wearable Medical Devices.

Science.gov (United States)

Khan, Yasser; Ostfeld, Aminy E; Lochner, Claire M; Pierre, Adrien; Arias, Ana C

2016-06-01

Advances in wireless technologies, low-power electronics, the internet of things, and in the domain of connected health are driving innovations in wearable medical devices at a tremendous pace. Wearable sensor systems composed of flexible and stretchable materials have the potential to better interface to the human skin, whereas silicon-based electronics are extremely efficient in sensor data processing and transmission. Therefore, flexible and stretchable sensors combined with low-power silicon-based electronics are a viable and efficient approach for medical monitoring. Flexible medical devices designed for monitoring human vital signs, such as body temperature, heart rate, respiration rate, blood pressure, pulse oxygenation, and blood glucose have applications in both fitness monitoring and medical diagnostics. As a review of the latest development in flexible and wearable human vitals sensors, the essential components required for vitals sensors are outlined and discussed here, including the reported sensor systems, sensing mechanisms, sensor fabrication, power, and data processing requirements. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Flexible Stretchable Hydrogel Electrolyte for Healable All-in-One Configured Supercapacitors.

Science.gov (United States)

Guo, Ying; Zheng, Kaiqiang; Wan, Pengbo

2018-04-01

The development of integrated high-performance supercapacitors with all-in-one configuration, excellent flexibility and autonomously intrinsic self-healability, and without the extra healable film layers, is still tremendously challenging. Compared to the sandwich-like laminated structures of supercapacitors with augmented interfacial contact resistance, the flexible healable integrated supercapacitor with all-in-one structure could theoretically improve their interfacial contact resistance and energy densities, simplify the tedious device assembly process, prolong the lifetime, and avoid the displacement and delamination of multilayered configurations under deformations. Herein, a flexible healable all-in-one configured supercapacitor with excellent flexibility and reliable self-healing ability by avoiding the extra healable film substrates and the postassembled sandwich-like laminated structures is developed. The healable all-in-one configured supercapacitor is prepared from in situ polymerization and deposition of nanocomposites electrode materials onto the two-sided faces of the self-healing hydrogel electrolyte separator. The self-healing hydrogel film is obtained from the physically crosslinked hydrogel with enormous hydrogen bonds, which can endow the healable capability through dynamic hydrogen bonding. The assembled all-in-one configured supercapacitor exhibits enhanced capacitive performance, good cycling stability, reliable self-healing capability, and excellent flexibility. It holds broad prospects for obtaining various flexible healable all-in-one configured supercapacitors for working as portable energy storage devices in wearable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-performance supercapacitors of carboxylate-modified hollow carbon nanospheres coated on flexible carbon fibre paper: Effects of oxygen-containing group contents, electrolytes and operating temperature

International Nuclear Information System (INIS)

Phattharasupakun, Nutthaphon; Wutthiprom, Juthaporn; Suktha, Phansiri; Iamprasertkun, Pawin; Chanlek, Narong; Shepherd, Celine; Hadzifejzovic, Emina; Moloney, Mark G.; Foord, John S.; Sawangphruk, Montree

2017-01-01

Although functionalized carbon-based materials have been widely used as the supercapacitor electrodes, the optimum contents of the functional groups, the charge storage mechanisms, and the effects of electrolytes and operating temperature have not yet been clearly investigated. In this work, carboxylate-modified hollow carbon nanospheres (c-HCN) with different functional group contents synthesized by an oxidation process of carbon nanospheres with nitric acid were coated on flexible carbon fibre paper and used as the supercapacitor electrodes. An as-fabricated supercapacitor of the c-HCN with a finely tuned 6.2 atomic % of oxygen of the oxygen-containing groups in an ionic liquid electrolyte exhibits a specific capacitance of 390 F g"−"1, a specific energy of 115 Wh kg"−"1, and a maximum specific power of 13548 W kg"−"1 at 70 °C. The charge storage mechanism investigated is based on the chemical adsorption of the ionic liquid electrolyte on the c-HCN electrode. This process is highly reversible leading to high capacity retention. The supercapacitor in this work may be practically used in many high energy and power applications.

Cellulose nanofibers/reduced graphene oxide flexible transparent conductive paper.

Science.gov (United States)

Gao, Kezheng; Shao, Ziqiang; Wu, Xue; Wang, Xi; Li, Jia; Zhang, Yunhua; Wang, Wenjun; Wang, Feijun

2013-08-14

The cellulose nanofibers (CNFs) paper exhibit high visible light transmittance, high mechanical strength, and excellent flexibility. Therefore, CNFs paper may be an excellent substrate material for flexible transparent electronic devices. In this paper, we endeavor to prepare CNFs-based flexible transparent conductive paper by layer-by-layer (LbL) assembly using divalent copper ions (Cu(2+)) as the crosslinking agent. The thickness of the reduced graphene oxide (RGO) active layer in the CNFs paper can be controlled by the cycle times of the LbL assembly. CNFs/[RGO]20 paper has the sheet resistances of ∼2.5 kΩ/□, and the transmittance of about 76% at a wavelength of 550 nm. Furthermore, CNFs/[RGO]20 paper inherits the excellent mechanical properties of CNFs paper, and the ultimate strength is about 136 MPa. CNFs-based flexible transparent conductive paper also exhibits excellent electrical stability and flexibility. Copyright © 2013. Published by Elsevier Ltd.

Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

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Pere Casan

1997-01-01

Full Text Available During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4, and incremental dead space to a maximum of 2638 mL (SD=452, associated with an increase in ventilation to 75.1 L/min (SD=29.79. Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2 to 299 mL/min (SD=52.3 and dyspnea increased to "very severe" (Borg scale 7.5, SD=1.55. During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2 to 426 mL/min (SD=81.9 and dyspnea increased to "very severe" (7.1, SD=0.66. Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3 with dead space loading and 91 mL/watt (95% confidence limits 54 to 128 with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3 during maximal resistive loading and 156 mL/min (SD 82.4 during maximal dead space loading (P<0.05. Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as

Temperature-dependent resistance switching in SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Li, Jian-kun [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Chao; Ge, Chen, E-mail: kjjin@iphy.ac.cn, E-mail: gechen@iphy.ac.cn; Gu, Lin; He, Xu; Zhou, Wen-jia; Lu, Hui-bin [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Jin, Kui-juan, E-mail: kjjin@iphy.ac.cn, E-mail: gechen@iphy.ac.cn [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100190 (China); Zhang, Qing-hua [School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Yang, Guo-zhen [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100190 (China)

2016-06-13

Resistance switching phenomena were studied by varying temperature in SrTiO{sub 3} single crystal. The resistance hysteresis loops appear at a certain temperature ranging from 340 K to 520 K. With the assistance of 375 nm ultraviolet continuous laser, the sample resistance is greatly reduced, leading to a stable effect than that in dark. These resistance switching phenomena only exist in samples with enough oxygen vacancies, which is confirmed by spherical aberration-corrected scanning transmission electron microscopy measurements, demonstrating an important role played by oxygen vacancies. At temperatures above 340 K, positively charged oxygen vacancies become mobile triggered by external electric field, and the resistance switching effect emerges. Our theoretical results based on drift-diffusion model reveal that the built-in field caused by oxygen vacancies can be altered under external electric field. Therefore, two resistance states are produced under the cooperative effect of built-in field and external field. However, the increasing mobility of oxygen vacancies caused by higher temperature promotes internal electric field to reach equilibrium states quickly, and suppresses the hysteresis loops above 420 K.

Extremely efficient flexible organic light-emitting diodes with modified graphene anode

Science.gov (United States)

Han, Tae-Hee; Lee, Youngbin; Choi, Mi-Ri; Woo, Seong-Hoon; Bae, Sang-Hoon; Hong, Byung Hee; Ahn, Jong-Hyun; Lee, Tae-Woo

2012-02-01

Although graphene films have a strong potential to replace indium tin oxide anodes in organic light-emitting diodes (OLEDs), to date, the luminous efficiency of OLEDs with graphene anodes has been limited by a lack of efficient methods to improve the low work function and reduce the sheet resistance of graphene films to the levels required for electrodes. Here, we fabricate flexible OLEDs by modifying the graphene anode to have a high work function and low sheet resistance, and thus achieve extremely high luminous efficiencies (37.2 lm W-1 in fluorescent OLEDs, 102.7 lm W-1 in phosphorescent OLEDs), which are significantly higher than those of optimized devices with an indium tin oxide anode (24.1 lm W-1 in fluorescent OLEDs, 85.6 lm W-1 in phosphorescent OLEDs). We also fabricate flexible white OLED lighting devices using the graphene anode. These results demonstrate the great potential of graphene anodes for use in a wide variety of high-performance flexible organic optoelectronics.

High throughput phenotypic selection of Mycobacterium tuberculosis mutants with impaired resistance to reactive oxygen species identifies genes important for intracellular growth.

Directory of Open Access Journals (Sweden)

Olga Mestre

Full Text Available Mycobacterium tuberculosis has the remarkable capacity to survive within the hostile environment of the macrophage, and to resist potent antibacterial molecules such as reactive oxygen species (ROS. Thus, understanding mycobacterial resistance mechanisms against ROS may contribute to the development of new anti-tuberculosis therapies. Here we identified genes involved in such mechanisms by screening a high-density transposon mutant library, and we show that several of them are involved in the intracellular lifestyle of the pathogen. Many of these genes were found to play a part in cell envelope functions, further strengthening the important role of the mycobacterial cell envelope in protection against aggressions such as the ones caused by ROS inside host cells.

Graphene-Based Flexible and Transparent Tunable Capacitors.

Science.gov (United States)

Man, Baoyuan; Xu, Shicai; Jiang, Shouzheng; Liu, Aihua; Gao, Shoubao; Zhang, Chao; Qiu, Hengwei; Li, Zhen

2015-12-01

We report a kind of electric field tunable transparent and flexible capacitor with the structure of graphene-Bi1.5MgNb1.5O7 (BMN)-graphene. The graphene films with low sheet resistance were grown by chemical vapor deposition. The BMN thin films were fabricated on graphene by using laser molecular beam epitaxy technology. Compared to BMN films grown on Au, the samples on graphene substrates show better quality in terms of crystallinity, surface morphology, leakage current, and loss tangent. By transferring another graphene layer, we fabricated flexible and transparent capacitors with the structure of graphene-BMN-graphene. The capacitors show a large dielectric constant of 113 with high dielectric tunability of ~40.7 % at a bias field of 1.0 MV/cm. Also, the capacitor can work stably in the high bending condition with curvature radii as low as 10 mm. This flexible film capacitor has a high optical transparency of ~90 % in the visible light region, demonstrating their potential application for a wide range of flexible electronic devices.

Thin, Flexible Secondary Li-Ion Paper Batteries

KAUST Repository

Hu, Liangbing

2010-10-26

There is a strong interest in thin, flexible energy storage devices to meet modern society needs for applications such as interactive packaging, radio frequency sensing, and consumer products. In this article, we report a new structure of thin, flexible Li-ion batteries using paper as separators and free-standing carbon nanotube thin films as both current collectors. The current collectors and Li-ion battery materials are integrated onto a single sheet of paper through a lamination process. The paper functions as both a mechanical substrate and separator membrane with lower impedance than commercial separators. The CNT film functions as a current collector for both the anode and the cathode with a low sheet resistance (∼5 Ohm/sq), lightweight (∼0.2 mg/cm2), and excellent flexibility. After packaging, the rechargeable Li-ion paper battery, despite being thin (∼300 μm), exhibits robust mechanical flexibility (capable of bending down to <6 mm) and a high energy density (108 mWh/g). © 2010 American Chemical Society.

A poly(dimethylsiloxane)-coated flexible mold for nanoimprint lithography

International Nuclear Information System (INIS)

Lee, Nae Yoon; Kim, Youn Sang

2007-01-01

In this paper, we introduce an anti-adhesion poly(dimethylsiloxane) (PDMS)-coated flexible mold and its applications for room-temperature imprint lithography. The flexible mold is fabricated using an ultraviolet-curable prepolymer on a flexible substrate, and its surface is passivated with a thin layer of PDMS to impart an anti-adhesion property. The highly flexible mold enables conformal contact with a substrate on which a low-viscosity polymer resist is spin-cast in a thin layer. Large-area imprinting is then realized at room temperature under significantly reduced pressure. The mold was durable even after repetitive imprinting of over 200 times. Also, we show a double imprinting on the substrate with a PDMS-coated replica polymeric mold having 500 nm line patterns. This enables the formation of matrix patterns with varying feature heights in less than 7 min

A new intermediate for the production of flexible stable polymers

Science.gov (United States)

Webster, J. A.

1973-01-01

Method of incorporating ether linkages into perfluoroalkylene segment of a dianydride intermediate yields intermediate that may be used in synthesis of flexible, stable polyimides for use as high-temperature, solvent-resistant sealants.

Highly Conductive, Transparent Flexible Films Based on Metal Nanoparticle-Carbon Nanotube Composites

Directory of Open Access Journals (Sweden)

Wen-Yin Ko

2013-01-01

Full Text Available Metallic nanoparticles decorated on MWCNTs based transparent conducting thin films (TCFs show a cheap and efficient option for the applications in touch screens and the replacement of the ITO film because of their interesting properties of electrical conductivity, mechanical property, chemical inertness, and other unique properties, which may not be accessible by their individual components. However, a great challenge that always remains is to develop effective ways to prepare junctions between metallic nanoparticles and MWCNTs for the improvement of high-energy barriers, high contact resistances, and weak interactions which could lead to the formation of poor conducting pathways and result in the CNT-based devices with low mechanical flexibility. Herein, we not only discuss recent progress in the preparation of MNP-CNT flexible TCFs but also describe our research studies in the relevant areas. Our result demonstrated that the MNP-CNT flexible TCFs we prepared could achieve a highly electrical conductivity with the sheet resistance of ~100 ohm/sq with ~80% transmittance at 550 nm even after being bent 500 times. This electrical conductivity is much superior to the performances of other MWCNT-based transparent flexible films, making it favorable for next-generation flexible touch screens and optoelectronic devices.

Textile Inspired Lithium-Oxygen Battery Cathode with Decoupled Oxygen and Electrolyte Pathways.

Science.gov (United States)

Xu, Shaomao; Yao, Yonggang; Guo, Yuanyuan; Zeng, Xiaoqiao; Lacey, Steven D; Song, Huiyu; Chen, Chaoji; Li, Yiju; Dai, Jiaqi; Wang, Yanbin; Chen, Yanan; Liu, Boyang; Fu, Kun; Amine, Khalil; Lu, Jun; Hu, Liangbing

2018-01-01

The lithium-air (Li-O 2 ) battery has been deemed one of the most promising next-generation energy-storage devices due to its ultrahigh energy density. However, in conventional porous carbon-air cathodes, the oxygen gas and electrolyte often compete for transport pathways, which limit battery performance. Here, a novel textile-based air cathode is developed with a triple-phase structure to improve overall battery performance. The hierarchical structure of the conductive textile network leads to decoupled pathways for oxygen gas and electrolyte: oxygen flows through the woven mesh while the electrolyte diffuses along the textile fibers. Due to noncompetitive transport, the textile-based Li-O 2 cathode exhibits a high discharge capacity of 8.6 mAh cm -2 , a low overpotential of 1.15 V, and stable operation exceeding 50 cycles. The textile-based structure can be applied to a range of applications (fuel cells, water splitting, and redox flow batteries) that involve multiple phase reactions. The reported decoupled transport pathway design also spurs potential toward flexible/wearable Li-O 2 batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of low temperature RF magnetron sputtered ITO films on flexible substrate

Energy Technology Data Exchange (ETDEWEB)

Muneshwar, T.P.; Varma, V.; Meshram, N; Soni, S.; Dusane, R.O. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

2010-09-15

Indium tin oxide (ITO) is one of the important materials used as transparent conducting oxide (TCO) layer in thin film solar cells, digital displays and other similar applications. For applications involving flexible polymeric substrates, it is important that deposition of ITO is carried out at near room temperature. This requirement puts constraint on stoichiometry leading to undesired electrical and optical properties. Effect of oxygen partial pressure on ITO films deposited on flexible Kapton {sup registered} by the RF magnetron sputtering is reported in this paper. (author)

SrRuO3 thin films grown on MgO substrates at different oxygen partial pressures

KAUST Repository

Zou, Bin

2013-01-08

A comprehensive study of SrRuO3 thin films growth on (001) MgO substrates by pulsed laser deposition in a wide oxygen pressure range from 10 to 300 mTorr was carried out. The experimental results showed a correlation between the lattice constants, resistivity, and oxygen partial pressures used. Ru deficiency detected only in films deposited at lower oxygen pressures (<50 mTorr), resulted in an elongation of the in-plane and out-of-plane lattice constants and an increase in the film resistivity. When deposited with oxygen partial pressure of 50 mTorr, SrRuO3 films had lattice parameters matching those of bulk SrRuO3 material and exhibited room temperature resistivity of 320 μΩ·cm. The resistivity of SrRuO 3/MgO films decreased with increasing oxygen partial pressure. Copyright © 2013 Materials Research Society.

Oxygen diffusion in Y sub 1 sub - sub x Pr sub x Ba sub 2 Cu sub 3 O sub 7 sub - subdelta observed by resistivity measurements

CERN Document Server

Diosa, J E; Mellander, B E

1997-01-01

In situ resistivity measurements have been used to monitor the oxygen uptake and removal for the ceramic system Y sub 1 sub - sub x Pr sub x Ba sub 2 Cu sub 3 O sub 7 sub - subdelta (YPBCO) in the temperature range 300 - 1000 K. The study of the out-diffusion of oxygen was performed by annealing the oxygenated samples in ambient air at constant heating rates. We found that, independently of x, the oxygen concentration O sub 7 sub - subdelta is preserved up to 600 K, and that oxygen diffuses out of the oxides at temperatures higher than 600 K. However, the rate of oxygen removal from PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta (PBCO) is greatly reduced as compared to the rate for pure YBa sub 2 Cu sub 3 O sub 7 sub - subdelta (YBCO), and decreases with increasing x in YPBCO. The study of the in-diffusion of oxygen was performed by annealing the deoxygenated samples in ambient air at constant heating rates. We found that, independently of x, the oxygen uptake takes place in the temperature range 550 - 750 K, whe...

Anisotropic Resistivities of Precisely Oxygen Controlled Single-Crystal Bi2Sr2CaCu2O8+δ: Systematic Study on ''Spin Gap'' Effect

International Nuclear Information System (INIS)

Watanabe, T.; Matsuda, A.; Fujii, T.; Matsuda, A.

1997-01-01

The in-plane resistivity ρ a (T) and the out-of-plane resistivity ρ c (T) have been systematically measured for Bi 2 Sr 2 CaCu 2 O 8+δ single crystals with their oxygen contents precisely controlled. In the underdoped region, deviation from T -linear in-plane resistivity, which evidences the opening of the spin gap, is clearly observed, while the out-of-plane resistivity is well reproduced by the activation-type phenomenological formula ρ c (T)=(a/T)exp (Δ/T)+c . In contrast to the YBa 2 Cu 3 O 7-δ system, we find that the onset of the semiconducting ρ c (T) does not coincide with the opening of the spin gap seen in the ρ a (T) in this Bi 2 Sr 2 CaCu 2 O 8+δ system. copyright 1997 The American Physical Society

Right ventricular oxygen supply/demand balance in exercising dogs.

Science.gov (United States)

Hart, B J; Bian, X; Gwirtz, P A; Setty, S; Downey, H F

2001-08-01

This is the first investigation of right ventricular (RV) myocardial oxygen supply/demand balance in a conscious animal. A novel technique developed in our laboratory was used to collect right coronary (RC) venous blood samples from seven instrumented, conscious dogs at rest and during graded treadmill exercise. Contributions of the RV oxygen extraction reserve and the RC flow reserve to exercise-induced increases in RV oxygen demand were measured. Strenuous exercise caused a 269% increase in RV oxygen consumption. Expanded arteriovenous oxygen content difference (A-V(Delta)O2) provided 58% of this increase in oxygen demand, and increased RC blood flow (RCBF) provided 42%. At less strenuous exercise, expanded A-V(Delta)O2 provided 60-80% of the required oxygen, and increases in RCBF were small and driven by increased aortic pressure. RC resistance fell only at strenuous exercise after the extraction reserve had been mobilized. Thus RC resistance was unaffected by large decreases in RC venous PO2 until an apparent threshold at 20 mmHg was reached. Comparisons of RV findings with published left ventricular data from exercising dogs demonstrated that increased O2 demand of the left ventricle is met primarily by increasing coronary flow, whereas increased O2 extraction makes a greater contribution to RV O2 supply.

Pulsed-laser-deposited, single-crystalline Cu2O films with low resistivity achieved through manipulating the oxygen pressure

Science.gov (United States)

Liu, Xiaohui; Xu, Meng; Zhang, Xijian; Wang, Weiguang; Feng, Xianjin; Song, Aimin

2018-03-01

Low-resistivity, single-crystalline Cu2O films were realized on MgO (110) substrates through manipulating the oxygen pressure (PO2) of pulsed-laser deposition. X-ray diffraction and high resolution transmission electron microscopy measurements revealed that the films deposited at PO2 of 0.06 and 0.09 Pa were single phase Cu2O and the 0.09-Pa-deposited film exhibited the best crystallinity with an epitaxial relationship of Cu2O (110)∥MgO (110) with Cu2O (001)∥MgO (001). The pure phase Cu2O films exhibited higher transmittances and larger band gaps with an optical band gap of 2.56 eV obtained for the 0.09 Pa-deposited film. Hall-effect measurements demonstrated that the Cu2O film deposited at 0.09 Pa had the lowest resistivity of 6.67 Ω cm and highest Hall mobility of 23.75 cm2 v-1 s-1.

Granular shear flows of flexible rod-like particles

Science.gov (United States)

Guo, Y.; Curtis, J.; Wassgren, C.; Ketterhagen, W.; Hancock, B.

2013-06-01

Flexible particles are widely encountered in nature, e.g., stalks of plants, fiberglass particles, and ceramic nanofibers. Early studies indicated that the deformability of particles has a significant impact on the properties of granular materials and fiber suspensions. In this study, shear flows of flexible particles are simulated using the Discrete Element Method (DEM) to explore the effect of particle flexibility on the flow behavior and constitutive laws. A flexible particle is formed by connecting a number of constituent spheres in a straight line using elastic bonds. The forces/moments due to the normal, tangential, bending, and torsional deformation of a bond resist the relative movement between two bonded constituent spheres. The bond stiffness determines how difficult it is to make a particle deform, and the bond damping accounts for the energy dissipation in the particle vibration process. The simulation results show that elastically bonded particles have smaller coefficients of restitution compared to rigidly connected particles, due to the fact that kinetic energy is partially converted to potential energy in a contact between flexible particles. The coefficient of restitution decreases as the bond stiffness decreases and the bond damping coefficient increases. As a result, smaller stresses are obtained for granular flows of the flexible particles with smaller bond stiffness and larger bond damping coefficient.

Transparent and flexible heaters based on Al:ZnO degenerate semiconductor

Science.gov (United States)

Roul, Monee K.; Obasogie, Brandon; Kogo, Gilbert; Skuza, J. R.; Mundle, R. M.; Pradhan, A. K.

2017-10-01

We report on high performance transparent Al:ZnO (AZO) thin film heaters on flexible polymer (polyethylene terephthalate) and glass substrates which demonstrate low sheet resistivity. AZO thin films were grown by radio-frequency magnetron sputtering at low Ts (below 200 °C) on flexible, transparent polyethylene terephthalate substrates that show stable and reproducible results by applying low (pain/injury therapy smart windows, automobile window defrosters, and low-cost power electronics.

Effect of Humid Aging on the Oxygen Adsorption in SnO₂ Gas Sensors.

Science.gov (United States)

Suematsu, Koichi; Ma, Nan; Watanabe, Ken; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

2018-01-16

To investigate the effect of aging at 580 °C in wet air (humid aging) on the oxygen adsorption on the surface of SnO₂ particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO₂ resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants ( K ₁; for O - adsorption, K ₂; for O 2- adsorption) were estimated on the basis of the theoretical model of oxygen adsorption. The K ₁ and K ₂ in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O - and O 2- . These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO₂ resistive-type gas sensors in dry and wet atmospheres.

Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

Science.gov (United States)

Majewski, Stanislaw; Kross, Brian J.; Zorn, Carl J.; Majewski, Lukasz A.

1996-01-01

An optimized examination system and method based on the Reverse Geometry X-Ray.RTM. (RGX.RTM.) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging.

Study of Ag/RGO/ITO sandwich structure for resistive switching behavior deposited on plastic substrate

Science.gov (United States)

Vartak, Rajdeep; Rag, Adarsh; De, Shounak; Bhat, Somashekhara

2018-05-01

We report here the use of facile and environmentally benign way synthesized reduced graphene oxide (RGO) for low-voltage non-volatile memory device as charge storing element. The RGO solutions have been synthesized using electrochemical exfoliation of battery electrode. The solution processed based RGO solution is suitable for large area and low-cost processing on plastic substrate. Room-temperature current-voltage characterisation has been carried out in Ag/RGO/ITO PET sandwich configuration to study the type of trap distribution. It is observed that in the low-voltage sweep, ohmic current is the main mechanism of current flow and trap filled/assisted conduction is observed at high-sweep voltage region. The Ag/RGO/ITO PET sandwich structure showed bipolar resistive switching behavior. These mechanisms can be analyzed based on oxygen availability and vacancies in the RGO giving rise to continuous least resistive path (conductive) and high resistance path along the structure. An Ag/RGO/ITO arrangement demonstrates long retention time with low operating voltage, low set/reset voltage, good ON/OFF ratio of 103 (switching transition between lower resistance state and higher resistance state and decent switching performance. The RGO memory showed decent results with an almost negligible degradation in switching properties which can be used for low-voltage and low-cost advanced flexible electronics.

A deeper look at the response of oxygenated and non oxygenated VOC to mid-term drought over the seasonal cycle: the case study of a drought-resistant species

Science.gov (United States)

Saunier, Amelie; Ormeño Lafuente, Elena; Wortham, Henri; Temime-Roussel, Brice; Fernandez, Catherine

2015-04-01

At the end of this century, climatic models plan an intensification of summer drought in the Mediterranean area due to a 30% rain reduction and a temperature rise of 3.4 °C. Plants respond to drought by modifying their primary (growth) and their secondary metabolism, the later being partly represented by volatile organic compound (VOC) emissions, such as terpenes. With drought, oxygenated and non oxygenated terpene emissions have been observed to increase, decrease or remain unchanged according to drought severity and vegetal model. By contrast, the response of non-terpenic oxygenated compounds to drought has been poorly studied. The aim of this study is to determine the potential impact of a two-year drought period on the full screen of VOC released by Q. pubescens, with a focus on both isoprene and methanol, issued from plant anabolism , and the numerous highly volatile oxygenated VOC, issued from plant catabolism (i.e. issued from oxidation of isoprene or methanol). A 70 years-old Downy oak forest (Quercus pubescens), highly resistant to drought stress, was selected as model ecosystem since it is well widespread in Southern France occupying 321 000 ha. Downy oak also represents the major source of isoprene emissions in the Mediterranean area and, unlike the other major Quercus sp. of the region (i.e. Quercus ilex, a monoterpene emitter) the impact of watering withholding over years has never been tackled. The study was performed at the experimental platform of O3HP (Oak Observatory at Observatoire de Haute Provence) in Southern France which is equipped with both a rain exclusion (by 30 %) and a rain addition structure (simulating the rainiest years of the region), allowing for comparison with naturally watered trees. Using dynamic enclosure chambers at the branch level and PTR-MS-Q-ToF, we screened the anabolic VOC (isoprene, methanol) and the catabolic VOC (e.g. methacrolein, methyl vinyl ketone, C6 aldehydes and carboxylic acids) of trees located under the

The Flexibility of Ectopic Lipids

Directory of Open Access Journals (Sweden)

Hannah Loher

2016-09-01

Full Text Available In addition to the subcutaneous and the visceral fat tissue, lipids can also be stored in non-adipose tissue such as in hepatocytes (intrahepatocellular lipids; IHCL, skeletal (intramyocellular lipids; IMCL or cardiac muscle cells (intracardiomyocellular lipids; ICCL. Ectopic lipids are flexible fuel stores that can be depleted by physical exercise and repleted by diet. They are related to obesity and insulin resistance. Quantification of IMCL was initially performed invasively, using muscle biopsies with biochemical and/or histological analysis. 1H-magnetic resonance spectroscopy (1H-MRS is now a validated method that allows for not only quantifying IMCL non-invasively and repeatedly, but also assessing IHCL and ICCL. This review summarizes the current available knowledge on the flexibility of ectopic lipids. The available evidence suggests a complex interplay between quantitative and qualitative diet, fat availability (fat mass, insulin action, and physical exercise, all important factors that influence the flexibility of ectopic lipids. Furthermore, the time frame of the intervention on these parameters (short-term vs. long-term appears to be critical. Consequently, standardization of physical activity and diet are critical when assessing ectopic lipids in predefined clinical situations.

Novel nanostructured oxygen sensor

Science.gov (United States)

Boardman, Alan James

New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

Roles of grain boundary and oxygen vacancies in Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} films for resistive switching device application

Energy Technology Data Exchange (ETDEWEB)

Yan, Xiaobing, E-mail: xiaobing-yan@126.com, E-mail: mseyanx@nus.edu.sg [Key Laboratory of Digital Medical Engineering of Hebei Province, College of Electron and Information Engineering, Hebei University, Baoding 071002 (China); Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore 117576 (Singapore); Li, Yucheng; Zhao, Jianhui; Li, Yan [Key Laboratory of Digital Medical Engineering of Hebei Province, College of Electron and Information Engineering, Hebei University, Baoding 071002 (China); Bai, Gang [College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Zhu, Siqi [Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632 (China)

2016-01-18

Oxygen vacancies are widely thought to be responsible for resistive switching (RS) effects based on polycrystalline oxides films. It is also well known that grain boundaries (GB) serve as reservoirs for accumulating oxygen vacancies. Here, Ar gas was introduced to enlarge the size of GB and increase the quantity of oxygen vacancies when the Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST) films were deposited by pulse laser deposition technique. The experimental results indicate that the RS properties of the device exhibits better in the Ar-introduced BST films than in the O{sub 2}-grown BST films. High resolution transmission electron microscopy images show that an amorphous region GB with large size appears between two lattice planes corresponding to oxygen vacancies defects in the Ar-introduced BST. Fourier-transform infrared reflectivity spectroscopy results also reveal highly accumulated oxygen vacancies in the Ar-introduced BST films. And we propose that the conduction transport of the cell was dominantly contributed from not ions migration of oxygen vacancies but the electrons in our case according to the value of activation energies of two kinds of films.

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

International Nuclear Information System (INIS)

Kaeaeriaeinen, Tommi O.; Maydannik, Philipp; Cameron, David C.; Lahtinen, Kimmo; Johansson, Petri; Kuusipalo, Jurkka

2011-01-01

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O 2 TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O 2 TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

Energy Technology Data Exchange (ETDEWEB)

Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

2011-03-01

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

Flexible, wearable, and functional graphene-textile composites

Science.gov (United States)

Liu, Ying; Zhang, Kun-Ning; Zhang, Ying; Tao, Lu-Qi; Li, Yu-Xing; Wang, Dan-Yang; Yang, Yi; Ren, Tian-Ling

2017-06-01

In this paper, a flexible, wearable, and functional graphene-textile composite is demonstrated. Laser scribing technology is applied to fabricate a graphene film. The thin layer of polydimethylsiloxane is covered on the surface of the graphene-textile film evenly, which would improve the abrasive resistance of the film, enhance the ability to adapt to environmental changes, and extend the service life, while maintaining the device's excellent flexibility and comfort. The graphene-textile composite can achieve constant temperature heating by controlling the input voltage, detect the human movement, and perceive the human pulse signal. The composite presents great commercial prospects and a large value in the medical, daily wear, and other areas that are closely related to human lives.

Strengthening of Back Muscles Using a Module of Flexible Strain Sensors

Directory of Open Access Journals (Sweden)

Wan-Chun Chuang

2015-02-01

Full Text Available This research aims at developing a flexible strain module applied to the strengthening of back muscles. Silver films were sputtered onto flexible substrates to produce a flexible sensor. Assuming that back muscle elongation is positively correlated with the variations in skin surface length, real-time resistance changes exhibited by the sensor during simulated training sessions were measured. The results were used to identify the relationship between resistance change of sensors and skin surface stretch. In addition, muscle length changes from ultrasound images were used to determine the feasibility of a proof of concept sensor. Furthermore, this module is capable of detecting large muscle contractions, some of which may be undesirable for the prescribed training strategy. Therefore, the developed module can facilitate real-time assessments of the movement accuracy of users during training, and the results are instantly displayed on a screen. People using the developed training system can immediately adjust their posture to the appropriate position. Thus, the training mechanism can be constructed to help user improve the efficiency of back muscle strengthening.

Surface Corrosion Resistance in Turning of Titanium Alloy

Directory of Open Access Journals (Sweden)

Rui Zhang

2015-01-01

Full Text Available This work addresses the issues associated with implant surface modification. We propose a method to form the oxide film on implant surfaces by dry turning to generate heat and injecting oxygen-rich gas at the turning-tool flank. The morphology, roughness, composition, and thickness of the oxide films in an oxygen-rich atmosphere were characterized using scanning electron microscopy, optical profiling, and Auger electron spectroscopy. Electrochemical methods were used to study the corrosion resistance of the modified surfaces. The corrosion resistance trends, analyzed relative to the oxide film thickness, indicate that the oxide film thickness is the major factor affecting the corrosion resistance of titanium alloys in a simulated body fluid (SBF. Turning in an oxygen-rich atmosphere can form a thick oxide film on the implant surface. The thickness of surface oxide films processed at an oxygen concentration of 80% was improved to 4.6 times that of films processed at an oxygen concentration of 21%; the free corrosion potential shifted positively by 0.357 V, which significantly improved the corrosion resistance of titanium alloys in the SBF. Therefore, the proposed method may (partially replace the subsequent surface oxidation. This method is significant for biomedical development because it shortens the process flow, improves the efficiency, and lowers the cost.

Microbial activity catalyzes oxygen transfer in membrane-aerated nitritating biofilm reactors

DEFF Research Database (Denmark)

Pellicer i Nàcher, Carles; Domingo Felez, Carlos; Lackner, Susanne

2013-01-01

The remarkable oxygen transfer efficiencies attainable in membrane-aerated biofilm reactors (MABRs) are expected to favor their prompt industrial implementation. However, tests in clean water, currently used for the estimation of their oxygen transfer potential, lead to wrong estimates once biofilm...... is present, significantly complicating reactor modelling and control. This study shows for the first time the factors affecting oxygen mass transfer across membranes during clean water tests and reactor operation via undisturbed microelectrode inspection and bulk measurements. The mass transfer resistance...... of the liquid boundary layer developed at the membrane-liquid interface during clean water tests accounted for two thirds of the total mass transfer resistance, suggesting a strong underestimation of the oxygen transfer rates when it is absent (e.g. after biofilm growth). Reactor operation to attain partial...

Effect of ultraviolet illumination on metal oxide resistive memory

KAUST Repository

Duran Retamal, Jose Ramon

2014-12-22

We investigate the photoelectrical and resistive switching properties of Pt/ZnO/Pt capacitor operated in unipolar mode under ultraviolet (UV) illumination. The oxygen photodesorption under UV illumination explains the photoconduction observed in initial and high resistance states. Meanwhile, oxygen readsorption at surface-related defects justifies the different photoresponses dynamics in both states. Finally, UV illumination significantly reduces the variations of resistance in high resistance state, set voltage and reset voltage by 58%, 33%, and 25%, respectively, stabilizing Pt/ZnO/Pt capacitor. Our findings in improved switching uniformity via UV light give physical insight into designing resistive memory devices.

Effect of ultraviolet illumination on metal oxide resistive memory

KAUST Repository

Duran Retamal, Jose Ramon; Kang, Chen-Fang; Ho, Chih-Hsiang; Ke, Jr-Jian; Chang, Wen-Yuan; He, Jr-Hau

2014-01-01

We investigate the photoelectrical and resistive switching properties of Pt/ZnO/Pt capacitor operated in unipolar mode under ultraviolet (UV) illumination. The oxygen photodesorption under UV illumination explains the photoconduction observed in initial and high resistance states. Meanwhile, oxygen readsorption at surface-related defects justifies the different photoresponses dynamics in both states. Finally, UV illumination significantly reduces the variations of resistance in high resistance state, set voltage and reset voltage by 58%, 33%, and 25%, respectively, stabilizing Pt/ZnO/Pt capacitor. Our findings in improved switching uniformity via UV light give physical insight into designing resistive memory devices.

Ultraviolet photodetection of flexible ZnO nanowire sheets in polydimethylsiloxane polymer.

Science.gov (United States)

Liu, Jinzhang; Motta, Nunzio; Lee, Soonil

2012-01-01

ZnO nanowires are normally exposed to an oxygen atmosphere to achieve high performance in UV photodetection. In this work we present results on a UV photodetector fabricated using a flexible ZnO nanowire sheet embedded in polydimethylsiloxane (PDMS), a gas-permeable polymer, showing reproducible UV photoresponse and enhanced photoconduction. PDMS coating results in a reduced response speed compared to that of a ZnO nanowire film in air. The rising speed is slightly reduced, while the decay time is prolonged by about a factor of four. We conclude that oxygen molecules diffusing in PDMS are responsible for the UV photoresponse.

Comparison Between the Acute Pulmonary Vascular Effects of Oxygen with Nitric Oxide and Sildenafil

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Ronald W. Day

2015-03-01

Full Text Available Objective. Right heart catheterization is performed in patients with pulmonary arterial hypertension to determine the severity of disease and their pulmonary vascular reactivity. The acute pulmonary vascular effect of inhaled nitric oxide is frequently used to identify patients who will respond favorably to vasodilator therapy. This study sought to determine whether the acute pulmonary vascular effects of oxygen with nitric oxide and intravenous sildenafil are similar. Methods. A retrospective, descriptive study of 13 individuals with pulmonary hypertension who underwent heart catheterization and acute vasodilator testing was performed. The hemodynamic measurements during five phases (21% to 53% oxygen, 100% oxygen, 100% oxygen with 20 ppm nitric oxide, 21% to 51% oxygen, and 21% to 51% oxygen with 0.05 mg/kg to 0.29 mg/kg intravenous sildenafil of the procedures were compared.Results. Mean pulmonary arterial pressure and pulmonary vascular resistance acutely decreased with 100% oxygen with nitric oxide, and 21% to 51% oxygen with sildenafil. Mean pulmonary arterial pressure (mm Hg, mean ± standard error of the mean was 38 ± 4 during 21% to 53% oxygen, 32 ± 3 during 100% oxygen, 29 ± 2 during 100% oxygen with nitric oxide, 37 ± 3 during 21% to 51% oxygen, and 32 ± 2 during 21% to 51% oxygen with sildenafil. There was not a significant correlation between the percent change in pulmonary vascular resistance from baseline with oxygen and nitric oxide, and from baseline with sildenafil (r2 = 0.011, p = 0.738. Conclusions. Oxygen with nitric oxide and sildenafil decreased pulmonary vascular resistance. However, the pulmonary vascular effects of oxygen and nitric oxide cannot be used to predict the acute response to sildenafil. Additional studies are needed to determine whether the acute response to sildenafil can be used to predict the long-term response to treatment with an oral phosphodiesterase V inhibitor.

Investigation of ITO layers for application as transparent contacts in flexible photovoltaic cell structures

Science.gov (United States)

Znajdek, Katarzyna; Sibiński, Maciej

2013-07-01

In this paper authors present the mechanical, optical and electrical parameters of Indium Tin Oxide (ITO) Transparent Conductive Layers (TCL) deposited on flexible substrate. Layers' properties are analyzed and verified. Investigated Transparent Conductive Oxide (TCO) was deposited, using magnetron sputtering method. Flexible polymer PET (polyethylene terephthalate) foil was used as a substrate, in order to photovoltaic (PV) cell's emitter contact application of investigated material. ITO-coated PET foils have been dynamically bent on numerous cylinders of various diameters according to the standard requirements. Resistance changes for each measured sample were measured and recorded during bending cycle. Thermal durability, as well as temperature influence on resistance and optical transmission are verified. Presented results were conducted to verify practical suitability and to evaluate possible applications of Indium Tin Oxide as a front contact in flexible photovoltaic cell structures.

Effect of Humid Aging on the Oxygen Adsorption in SnO2 Gas Sensors

Directory of Open Access Journals (Sweden)

Koichi Suematsu

2018-01-01

Full Text Available To investigate the effect of aging at 580 °C in wet air (humid aging on the oxygen adsorption on the surface of SnO2 particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO2 resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants (K1; for O− adsorption, K2; for O2− adsorption were estimated on the basis of the theoretical model of oxygen adsorption. The K1 and K2 in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O− and O2−. These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO2 resistive-type gas sensors in dry and wet atmospheres.

Surface-Controlled Metal Oxide Resistive Memory

KAUST Repository

Ke, Jr-Jian

2015-10-28

To explore the surface effect on resistive random-access memory (ReRAM), the impact of surface roughness on the characteristics of ZnO ReRAM were studied. The thickness-independent resistance and the higher switching probability of ZnO ReRAM with rough surfaces indicate the importance of surface oxygen chemisorption on the switching process. Furthermore, the improvements in switching probability, switching voltage and resistance distribution observed for ReRAM with rough surfaces can be attributed to the stable oxygen adatoms under various ambience conditions. The findings validate the surface-controlled stability and uniformity of ReRAM and can serve as the guideline for developing practical device applications.

Highly flexible peeled-off silver nanowire transparent anode using in organic light-emitting devices

Energy Technology Data Exchange (ETDEWEB)

Duan, Ya-Hui; Duan, Yu, E-mail: duanyu@jlu.edu.cn; Wang, Xiao; Yang, Dan; Yang, Yong-Qiang; Chen, Ping; Sun, Feng-Bo; Xue, Kai-Wen; Zhao, Yi

2015-10-01

Graphical abstract: - Highlights: • An ultra-smooth AgNW film on a flexible photopolymer substrate has been fabricated. • The AgNW film has a low sheet resistance with high transparency and flexibility. • OLEDs based on AgNW:NOA63 substrate can be bent at a radius of curvature of 2 mm. - Abstract: Materials to replace indium tin oxide (ITO) for high transmittance and electrical conductivity are urgently needed. In this paper, we adopted a silver nanowire (AgNW)-photopolymer (NOA63) film as a new platform for flexible optoelectronic devices. This design combined a transparent electrode and a flexible substrate. We utilized this application to obtain flexible organic light-emitting devices (FOLEDs). A peel-off process combined with a spin-coating process created an ultra-smooth silver nanowire anode on a photopolymer substrate. The performance of the device was achieved via the perfect morphology of the AgNW anode, the optimal 5 mg/ml concentration of AgNW solution, and the 45.7 Ω/□ sheet resistance of the AgNW film. The maximum current efficiency of the FOLED is 13 cd/A with stable mechanical flexibility even when bent to a radius of curvature of 2 mm. The outstanding performance of the FOLED with peeled off AgNW anode shows that this approach is a promising alternative to ITO for FOLEDs.

Two-beam laser fabrication technique and the application for fabricating conductive silver nanowire on flexible substrate

Directory of Open Access Journals (Sweden)

Gui-Cang He

2017-03-01

Full Text Available In this study, a two-beam laser fabrication technique is proposed to fabricate silver nanowire (AgNW on the polyethylene terephthalate (PET substrate. The femtosecond pulse laser in the technique plays a role in generating Ag nanoparticles from the silver aqueous solution by multiphoton photoreduction. The continuous wave (CW laser of the technique works as optical tweezers, and make the Ag nanoparticles gather to a continuous AgNW by the optical trapping force. The optical trapping force of the CW laser was calculated under our experimental condition. The flexibility and the resistance stability of the AgNW that fabricated by this technique are very excellent. Compared to the resistance of the AgNW without bending, the decreasing rate of the AgNW resistance is about 16% under compressed bending condition at the radius of 1 mm, and the increasing rate of the AgNW resistance is only 1.3% after the AgNW bended about 3500 times at the bending radius of 1 mm. The study indicates that the AgNW is promising for achieving flexible device and would promote the development of the flexible electronics.

CVD-Graphene-Based Flexible, Thermoelectrochromic Sensor

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Adam Januszko

2017-01-01

Full Text Available The main idea behind this work was demonstrated in a form of a new thermoelectrochromic sensor on a flexible substrate using graphene as an electrically reconfigurable thermal medium (TEChrom™. Our approach relies on electromodulation of thermal properties of graphene on poly(ethylene terephthalate (PET via mechanical destruction of a graphene layer. Graphene applied in this work was obtained by chemical vapor deposition (CVD technique on copper substrate and characterized by Raman and scanning tunneling spectroscopy. Electrical parameters of graphene were evaluated by the van der Pauw method on the transferred graphene layers onto SiO2 substrates by electrochemical delamination method. Two configurations of architecture of sensors, without and with the thermochromic layer, were investigated, taking into account the increase of voltage from 0 to 50 V and were observed by thermographic camera to define heat energy. Current-voltage characteristics obtained for the sensor with damaged graphene layer are linear, and the resistivity is independent from the current applied. The device investigated under 1000 W/m2 exhibited rise of resistivity along with increased temperature. Flexible thermoelectrochromic device with graphene presented here can be widely used as a sensor for both the military and civil monitoring.

Oxygen dependency of porfiromycin cytotoxicity

International Nuclear Information System (INIS)

Marshall, R.S.; Rauth, A.M.

1987-01-01

The authors determined the oxygen dependency of toxicity for the bioreductive alkylating agents mitomycin C (MMC) and porfiromycin (PM) to investigate whether the toxicities of these agents increase in the range of oxygen tensions over which cells become increasingly radioresistant. In the present work the oxygen dependency of PM in CHO cells was determined by assaying survival as a function of time of exposure to 1.0 μg/ml PM under various known levels of oxygen. While PM demonstrated preferential hypoxic cell toxicity, aerobic cell survival was reduced ten-fold after five hours of exposure. Conversely, PM toxicity after a five hour hypoxic exposure to <0.001% oxygen appeared to be greater than that observed for similar MMC exposures, suggesting that PM may be more selective than MMC in killing hypoxic rather than aerobic cells. The authors are currently investigating this preferential toxicity in two human cell lines, one of which is resistant to these agents. At present, these observations suggest that PM may be more effective than MMC at destroying tumour cells in regions of intermediate and low oxygen tensions which may survive radiotherapy, though the range of oxygen tensions which mediate toxicity is similar for both agents

Quadruple labelled dual oxygen and pH-sensitive ratiometric nanosensors

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Veeren M. Chauhan

2016-05-01

Full Text Available Nanosensors capable of simultaneously measuring dissolved oxygen concentrations from 0 to 100% saturation and pH over the full physiological range, from pH 3.5 to 7.5, that advance the methods towards understanding of key biological gradients, were synthesised. A library of water soluble oxygen-sensitive porphyrins, with three substituted charged functional groups and a chemically flexible carboxylate functional group were spectroscopically analysed to assess their sensitivity to changes in dissolved oxygen concentrations as free species in solution and in suspension as nanoparticle conjugates. A platinum cationic porphyrin was taken forward to fabricate ratiometric oxygen-sensitive nanosensors, using 5-(and-6-carboxytetramethylrhodamine (TAMRA as internal standard. In addition, quadruple labelled dual oxygen and pH-sensitive nanosensors were synthesised using the cationic Pt porphyrin, pH-sensitive fluorescein dyes, carboxyfluorescein (FAM and Oregon Green (OG, in a 1:1 ratio, and TAMRA. We envisage the dual oxygen and pH nanosensors will find broad utility in the characterisation of diverse microenvironments, where there are complex interactions between molecular oxygen and pH. Keywords: Fluorescent, Phosphorescent, Nanosensor, Oxygen, pH, Ratiometric, Platinum metalloporphyrin

Effect of resistive training on the maximum strenght,flexibility and functional autonomy of elderly woman

Directory of Open Access Journals (Sweden)

Estélio Henrique Martin Dantas

2006-12-01

Full Text Available The objective of this study was to investigate the effects of resistive training on maximum strength, flexibility and functional autonomy, as well as the correlation between maximum strength and functional autonomy of the elderly women (strength group, GF, n=11, = 66.3 ± 7.84 years/control group, GC, n=11, =65.1 ± 3.33 years. They participated of a resistive training (75-85% 1RM during 16 weeks, 2 days/week. Statistical procedures were Pearson’s correlation and Student t-test, using the SPSS package, version 12.0. Data showed signifi cant results for GF on the strength, fl exibility and functional autonomy, and signifi cant correlation between strength and functional autonomy (r=-0.67. The data suggested that training program enhances performance in activities of daily living with a training protocol of only 2 days/week. RESUMO O objetivo desse estudo foi verifi car os efeitos do treinamento resistido na força máxima, na fl exibilidade e na autonomia funcional, bem como a correlação existente entre a força máxima e a autonomia funcional de idosas (grupo de força - GF n=11, = 66,3±7,84 anos e um grupo controle - GC n=11, =65,1±3,33 anos. O GF foi submetido a um treinamento contra resistência de força (75-85% 1RM, por 16 semanas, 2 dias/semana. O tratamento estatístico utilizado foi correlação de Pearson e o teste “t” de Student. Os dados mostraram resultados signifi cativos do GF no ganho da força máxima, fl exibilidade e autonomia funcional, e correlação signifi cativa entre a força máxima medida no exercício supino reto (SR e o teste de autonomia funcional levantar da posição de decúbito ventral (LPDV (r=-0,67. Os dados sugerem que o programa de treinamento melhorou o desempenho das atividades da vida diária da amostra, com um treinamento de apenas 2 dias/semana.

Cu mesh for flexible transparent conductive electrodes.

Science.gov (United States)

Kim, Won-Kyung; Lee, Seunghun; Hee Lee, Duck; Hee Park, In; Seong Bae, Jong; Woo Lee, Tae; Kim, Ji-Young; Hun Park, Ji; Chan Cho, Yong; Ryong Cho, Chae; Jeong, Se-Young

2015-06-03

Copper electrodes with a micromesh/nanomesh structure were fabricated on a polyimide substrate using UV lithography and wet etching to produce flexible transparent conducting electrodes (TCEs). Well-defined mesh electrodes were realized through the use of high-quality Cu thin films. The films were fabricated using radio-frequency (RF) sputtering with a single-crystal Cu target--a simple but innovative approach that overcame the low oxidation resistance of ordinary Cu. Hybrid Cu mesh electrodes were fabricated by adding a capping layer of either ZnO or Al-doped ZnO. The sheet resistance and the transmittance of the electrode with an Al-doped ZnO capping layer were 6.197 ohm/sq and 90.657%, respectively, and the figure of merit was 60.502 × 10(-3)/ohm, which remained relatively unchanged after thermal annealing at 200 °C and 1,000 cycles of bending. This fabrication technique enables the mass production of large-area flexible TCEs, and the stability and high performance of Cu mesh hybrid electrodes in harsh environments suggests they have strong potential for application in smart displays and solar cells.

Micro-aerobics: when rice plants lose their resistance against oxygen

International Nuclear Information System (INIS)

Reuss, J; Harren, F J M

2008-01-01

Photoacoustic determination of ethane, ethanol and acetaldehyde releases from 14 d old rice seedlings leads to the conclusion that rice seedlings start suffering significant lipid peroxidation under micro-aerobic conditions. To produce micro-aerobic conditions in otherwise normal atmospheres, the oxygen concentration has been reduced to a value between 0.3 and 0.05% (v/v). The defense of the rice seedlings against oxygenic radicals becomes insufficient under these almost anaerobic conditions. The findings presented here are relevant for the clarification of what causes non-survival of rice seedlings under prolonged submergence.

Gigahertz flexible graphene transistors for microwave integrated circuits.

Science.gov (United States)

Yeh, Chao-Hui; Lain, Yi-Wei; Chiu, Yu-Chiao; Liao, Chen-Hung; Moyano, David Ricardo; Hsu, Shawn S H; Chiu, Po-Wen

2014-08-26

Flexible integrated circuits with complex functionalities are the missing link for the active development of wearable electronic devices. Here, we report a scalable approach to fabricate self-aligned graphene microwave transistors for the implementation of flexible low-noise amplifiers and frequency mixers, two fundamental building blocks of a wireless communication receiver. A devised AlOx T-gate structure is used to achieve an appreciable increase of device transconductance and a commensurate reduction of the associated parasitic resistance, thus yielding a remarkable extrinsic cutoff frequency of 32 GHz and a maximum oscillation frequency of 20 GHz; in both cases the operation frequency is an order of magnitude higher than previously reported. The two frequencies work at 22 and 13 GHz even when subjected to a strain of 2.5%. The gigahertz microwave integrated circuits demonstrated here pave the way for applications which require high flexibility and radio frequency operations.

Mechanisms of group A Streptococcus resistance to reactive oxygen species.

Science.gov (United States)

Henningham, Anna; Döhrmann, Simon; Nizet, Victor; Cole, Jason N

2015-07-01

Streptococcus pyogenes, also known as group A Streptococcus (GAS), is an exclusively human Gram-positive bacterial pathogen ranked among the 'top 10' causes of infection-related deaths worldwide. GAS commonly causes benign and self-limiting epithelial infections (pharyngitis and impetigo), and less frequent severe invasive diseases (bacteremia, toxic shock syndrome and necrotizing fasciitis). Annually, GAS causes 700 million infections, including 1.8 million invasive infections with a mortality rate of 25%. In order to establish an infection, GAS must counteract the oxidative stress conditions generated by the release of reactive oxygen species (ROS) at the infection site by host immune cells such as neutrophils and monocytes. ROS are the highly reactive and toxic byproducts of oxygen metabolism, including hydrogen peroxide (H2O2), superoxide anion (O2•(-)), hydroxyl radicals (OH•) and singlet oxygen (O2*), which can damage bacterial nucleic acids, proteins and cell membranes. This review summarizes the enzymatic and regulatory mechanisms utilized by GAS to thwart ROS and survive under conditions of oxidative stress. © FEMS 2015.

Measurement of oxygen transfer from air into organic solvents

DEFF Research Database (Denmark)

Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

2016-01-01

biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...... applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

Green synthesized silver nanoparticles destroy multidrug resistant bacteria via reactive oxygen species mediated membrane damage

Directory of Open Access Journals (Sweden)

Balaram Das

2017-09-01

Full Text Available The growing need of antimicrobial agent for novel therapies against multi-drug resistant bacteria has drawn researchers to green nanotechnology. Especially, eco-friendly biosynthesis of silver nanoparticles (Ag NPs has shown its interesting impact against bacterial infection in laboratory research. In this study, a simple method was developed to form Ag NPs at room temperature, bio-reduction of silver ions from silver nitrate salt by leaf extract from Ocimum gratissimum. The Ag NPs appear to be capped with plant proteins, but are otherwise highly crystalline and pure. The Ag NPs have a zeta potential of −15 mV, a hydrodynamic diameter of 31 nm with polydispersity index of 0.65, and dry sizes of 18 ± 3 nm and 16 ± 2 nm, based on scanning and transmission electron microscopy respectively. The minimum inhibitory concentration (MIC of the Ag NPs against a multi-drug resistant Escherichia coli was 4 μg/mL and the minimum bactericidal concentration (MBC was 8 μg/mL, while the MIC and MBC against a resistant strain of Staphylococcus aureus were slightly higher at 8 μg/mL and 16 μg/mL respectively. Further, the Ag NPs inhibited biofilm formation by both Escherichia coli and S. aureus at concentrations similar to the MIC for each strain. Treatment of E. coli and S. aureus with Ag NPs resulted in damage to the surface of the cells and the production of reactive oxygen species. Both mechanisms likely contribute to bacterial cell death. In summary, this new method appears promising for green biosynthesis of pure Ag NPs with potent antimicrobial activity.

Characteristics of low-resistivity aluminum-doped zinc oxide films deposited at room temperature by off-axis radio-frequency sputtering on flexible plastic substrates

Science.gov (United States)

Wang, Li-Min; Wang, Chih-Yi; Jheng, Ciao-Ren; Wu, Syu-Jhan; Sai, Chen-Kai; Lee, Ya-Ju; Chiang, Ching-Yu; Shew, Bor-Yuan

2016-08-01

The crystalline structure, morphology, composition, electrical transport, and optical properties of aluminum-doped zinc oxide (AZO) films are studied for applications in transparent electronics and optoelectronic devices. AZO thin films of c-axis-oriented growth and with different thickness were deposited on PET flexible plastic substrates at room temperature by rf magnetron sputtering. A larger grain size with a decreased strain ɛ value is observed in a thicker film, while changes in composition for films with different thicknesses are insignificant. Moreover, the resistivity of film decreases with increasing thickness, and the low-temperature electrical transport properties can be described by the scenario of quantum corrections to conductivity. With the room-temperature growth conditions, the resistivity of 4.5 × 10-4 Ω cm, carrier concentration of 6.4 × 1020 cm-3, and transmittance of 80 % for the 1100-nm-thick film are obtained. In addition, the optical bandgap energy decreases with increasing film thickness, which can be attributed to the bandgap renormalization and crystallite size effects.

Flexible indium zinc oxide/Ag/indium zinc oxide multilayer electrode grown on polyethersulfone substrate by cost-efficient roll-to-roll sputtering for flexible organic photovoltaics

International Nuclear Information System (INIS)

Park, Yong-Seok; Kim, Han-Ki

2010-01-01

The authors describe the preparation and characteristics of flexible indium zinc oxide (IZO)-Ag-IZO multilayer electrodes grown on flexible polyethersulfone (PES) substrates using a roll-to-roll sputtering system for use in flexible organic photovoltaics. By the continuous roll-to-roll sputtering of the bottom IZO, Ag, and top IZO layers at room temperature, they were able to fabricate a high quality IZO-Ag-IZO multilayer electrode with a sheet resistance of 6.15 ε/square, optical transmittance of 87.4%, and figure of merit value of 42.03x10 -3 Ω -1 on the PES substrate. In addition, the IZO-Ag-IZO multilayer electrode exhibited superior flexibility to the roll-to-roll sputter grown single ITO electrode due to the existence of a ductile Ag layer between the IZO layers and stable amorphous structure of the IZO film. Furthermore, the flexible organic solar cells (OSCs) fabricated on the roll-to-roll sputter grown IZO-Ag-IZO electrode showed higher power efficiency (3.51%) than the OSCs fabricated on the roll-to-roll sputter grown single ITO electrode (2.67%).

Superhydrophobicity enhancement through substrate flexibility

Science.gov (United States)

Vasileiou, Thomas; Gerber, Julia; Prautzsch, Jana; Schutzius, Thomas; Poulikakos, Dimos

2017-11-01

Inspired by manifestations in nature, micro/nanoengineering superhydrophobic surfaces has been the focus of much work. Generally, hydrophobicity is increased through the combined effects of surface texturing and chemistry; being durable, rigid substrate materials are the norm. However, many natural and technical materials are flexible, and the resulting effect on hydrophobicity has been largely unexplored. Here, we show that the rational tuning of flexibility can work collaboratively with the surface micro/nanotexture to enhance liquid repellency performance, defined by impalement and breakup resistance, contact time reduction, and restitution coefficient increase. Reduction in substrate stiffness and areal density imparts immediate acceleration and intrinsic responsiveness to impacting droplets, mitigating the collision and lowering the impalement probability by 60 % without the need for active actuation. We demonstrate the above discoveries with materials ranging from thin steel or polymer sheets to butterfly wings. Partial support of the Swiss National Science Foundation under Grant 162565 and the European Research Council under Advanced Grant 669908 (INTICE) is acknowledged.

Ultraviolet photodetection of flexible ZnO nanowire sheets in polydimethylsiloxane polymer

Directory of Open Access Journals (Sweden)

Jinzhang Liu

2012-05-01

Full Text Available ZnO nanowires are normally exposed to an oxygen atmosphere to achieve high performance in UV photodetection. In this work we present results on a UV photodetector fabricated using a flexible ZnO nanowire sheet embedded in polydimethylsiloxane (PDMS, a gas-permeable polymer, showing reproducible UV photoresponse and enhanced photoconduction. PDMS coating results in a reduced response speed compared to that of a ZnO nanowire film in air. The rising speed is slightly reduced, while the decay time is prolonged by about a factor of four. We conclude that oxygen molecules diffusing in PDMS are responsible for the UV photoresponse.

Selecting an oxygen plant for a copper smelter modernization

Science.gov (United States)

Larson, Kenneth H.; Hutchison, Robert L.

1994-10-01

The selection of an oxygen plant for the Cyprus Miami smelter modernization project began with a good definition of the use requirements and the smelter process variables that can affect oxygen demand. To achieve a reliable supply of oxygen with a reasonable amount of capital, critical equipment items were reviewed and reliability was added through the use of installed spares, purchase of insurance spare parts or the installation of equipment design for 50 percent of the production design such that the plant could operate with one unit while the other unit is being maintained. The operating range of the plant was selected to cover variability in smelter oxygen demand, and it was recognized that the broader operating range sacrificed about two to three percent in plant power consumption. Careful consideration of the plant "design point" was important to both the capital and operating costs of the plant, and a design point was specified that allowed a broad range of operation for maximum flexibility.

The effect of temperature and pressure on the oxygen reduction reactions in polyelectrolyte membranes

Energy Technology Data Exchange (ETDEWEB)

Holdcroft, S.; Abdou, M.S.; Beattie, P.; Basura, V. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Chemistry

1997-12-31

The effect of temperature and pressure on the oxygen reduction reaction in polyelectrolyte membranes was described. Polyelectrolytes chosen for the experiment differed in composition, weight and flexibility of the polymer chains. The study was conducted in a solid state electrochemical cell at temperatures between 30 and 95 degrees C and in the pressure range of 1 to 5 atm. The solubility of oxygen in these membranes was found to follow Henry`s Law, while the diffusion coefficient decreased with pressure. The effect of temperature on the solubility of oxygen and the diffusion coefficient of oxygen in the membranes was similar to that observed in solution electrolytes. 2 refs., 3 figs.

The dynamics of ultraviolet-induced oxygen vacancy at the surface of insulating SrTiO_3(0 0 1)

International Nuclear Information System (INIS)

Suwanwong, S.; Eknapakul, T.; Rattanachai, Y.; Masingboon, C.; Rattanasuporn, S.; Phatthanakun, R.; Nakajima, H.; King, P.D.C.; Hodak, S.K.; Meevasana, W.

2015-01-01

Highlights: • The dynamics of UV-induced oxygen vacancy is studied from the change of surface resistance. • The formation of 2DEG at the insulating surface of SrTiO_3 is confirmed by ARPES. • The UV-induced change in resistance responds differently to oxygen/gas exposure. • The behavior of resistance recovery suggests an alternative method of low-pressure sensing. - Abstract: The effect of ultra-violet (UV) irradiation on the electronic structure and the surface resistance of an insulating SrTiO_3(0 0 1) crystal is studied in this work. Upon UV irradiation, we show that the two-dimensional electron gas (2DEG) emerges at the insulating SrTiO_3 surface and there is a pronounced change in the surface resistance. By combining the observations of the change in valance band and the resistance change under different environments of gas pressure and gas species, we find that UV-induced oxygen vacancies at the surface plays a major role in the resistance change. The dynamic of the resistance change at different oxygen pressures also suggests an alternative method of low-pressure sensing.

Combined impact of water column oxygen and temperature on internal oxygen status and growth of Zostera marina seedlings and adult shoots

DEFF Research Database (Denmark)

Raun, Ane-Marie Løvendahl; Borum, Jens

2013-01-01

Eelgrass (Zostera marina L.) occasionally experiences severe die-offs during warm summer periods with variable water column oxygen partial pressures (pO). Eelgrass is known to be very intolerant to tissue anoxia with reduced growth and increasing mortality after ≤12h anoxia in the dark...... at temperatures of ≥25°C. In the present study we experimentally examine the impact of combined water column oxygen and temperature on oxygen dynamics in leaf meristems of seedlings and adult shoots to better understand how stressful environmental conditions affect eelgrass oxygen dynamics and subsequent growth...... and mortality. There was a strong interaction between water column oxygen and temperature on meristem pO implying that eelgrass is rather resistant to unfavorable oxygen conditions in winter but becomes increasingly vulnerable in summer, especially at high temperatures. At 25°C meristems became anoxic...

Low-Cost Facile Fabrication of Flexible Transparent Copper Electrodes by Nanosecond Laser Ablation

KAUST Repository

Paeng, Dongwoo

2015-03-27

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Low-cost Cu flexible transparent conducting electrodes (FTCEs) are fabricated by facile nanosecond laser ablation. The fabricated Cu FTCEs show excellent opto-electrical properties (transmittance: 83%, sheet resistance: 17.48 Ω sq^-1) with outstanding mechanical durability. Successful demonstration of a touch-screen panel confirms the potential applicability of Cu FTCEs to the flexible optoelectronic devices.

Flexible powder electroluminescent device on silver nanowire electrode

International Nuclear Information System (INIS)

Park, K.W.; Jeong, H.S.; Park, J.H.; Deressa, G.; Jeong, Y.T.; Lim, K.T.; Park, J.H.; Lee, S.H.; Kim, J.S.

2015-01-01

We have demonstrated the flexible AC powder electroluminescent device based on Ag nanowire electrode. The Ag nanowire electrode showed the nanowire morphology of 20 nm in diameter and 15 μm in length, the transmittance of 87%, and the sheet resistance of 50 Ω/sq, and the higher flexibility than the conventional ITO substrate. The electroluminescence spectra of the Ag nanowire-based device in all frequency and voltage ranges were almost similar with the ITO-based device. In comparison with the ITO-based device, the luminous efficiency of the Ag nanowire-based device was almost same as 1.53 lm/W. - Highlights: • Flexibility of Ag NW substrate was higher than ITO substrate. • EL intensity of Ag NW-based EL device was almost similar with ITO-based EL device. • Charge density and turn-on voltage of Ag NW-based EL device were a little larger than ITO-based EL device

Flexible powder electroluminescent device on silver nanowire electrode

Energy Technology Data Exchange (ETDEWEB)

Park, K.W.; Jeong, H.S.; Park, J.H.; Deressa, G.; Jeong, Y.T.; Lim, K.T. [Department of Display Science and Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Park, J.H. [AIDEN company, Cheongju-si 361-911 (Korea, Republic of); Lee, S.H. [R& D Business Lab, Hyosung Corporation, Anyang 431-080 (Korea, Republic of); Kim, J.S., E-mail: jsukim@pknu.ac.kr [Department of Display Science and Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2015-09-15

We have demonstrated the flexible AC powder electroluminescent device based on Ag nanowire electrode. The Ag nanowire electrode showed the nanowire morphology of 20 nm in diameter and 15 μm in length, the transmittance of 87%, and the sheet resistance of 50 Ω/sq, and the higher flexibility than the conventional ITO substrate. The electroluminescence spectra of the Ag nanowire-based device in all frequency and voltage ranges were almost similar with the ITO-based device. In comparison with the ITO-based device, the luminous efficiency of the Ag nanowire-based device was almost same as 1.53 lm/W. - Highlights: • Flexibility of Ag NW substrate was higher than ITO substrate. • EL intensity of Ag NW-based EL device was almost similar with ITO-based EL device. • Charge density and turn-on voltage of Ag NW-based EL device were a little larger than ITO-based EL device.

Insulin sensitivity and metabolic flexibility following exercise training among different obese insulin-resistant phenotypes.

Science.gov (United States)

Malin, Steven K; Haus, Jacob M; Solomon, Thomas P J; Blaszczak, Alecia; Kashyap, Sangeeta R; Kirwan, John P

2013-11-15

Impaired fasting glucose (IFG) blunts the reversal of impaired glucose tolerance (IGT) after exercise training. Metabolic inflexibility has been implicated in the etiology of insulin resistance; however, the efficacy of exercise on peripheral and hepatic insulin sensitivity or substrate utilization in adults with IFG, IGT, or IFG + IGT is unknown. Twenty-four older (66.7 ± 0.8 yr) obese (34.2 ± 0.9 kg/m(2)) adults were categorized as IFG (n = 8), IGT (n = 8), or IFG + IGT (n = 8) according to a 75-g oral glucose tolerance test (OGTT). Subjects underwent 12-wk of exercise (60 min/day for 5 days/wk at ∼85% HRmax) and were instructed to maintain a eucaloric diet. A euglycemic hyperinsulinemic clamp (40 mU·m(2)·min(-1)) with [6,6-(2)H]glucose was used to determine peripheral and hepatic insulin sensitivity. Nonoxidative glucose disposal and metabolic flexibility [insulin-stimulated respiratory quotient (RQ) minus fasting RQ] were also assessed. Glucose incremental area under the curve (iAUCOGTT) was calculated from the OGTT. Exercise increased clamp-derived peripheral and hepatic insulin sensitivity more in adults with IFG or IGT alone than with IFG + IGT (P work is required to assess the molecular mechanism(s) by which chronic hyperglycemia modifies insulin sensitivity following exercise training.

Flexibility.

Science.gov (United States)

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)

Comparison of home- and gymnasium-based resistance training on ...

African Journals Online (AJOL)

Comparison of home- and gymnasium-based resistance training on flexibility in the ... which is especially essential in the maintenance of functional abilities of the ... the effects of a home- and gymnasium-based resistance training programme ...

Tuning the resistive switching properties of TiO2-x films

Science.gov (United States)

Ghenzi, N.; Rozenberg, M. J.; Llopis, R.; Levy, P.; Hueso, L. E.; Stoliar, P.

2015-03-01

We study the electrical characteristics of TiO2-x-based resistive switching devices fabricated with different oxygen/argon flow ratio during the oxide thin film sputtering deposition. Upon minute changes in this fabrication parameter, three qualitatively different device characteristics were accessed in the same system, namely, standard bipolar resistive switching, electroforming-free devices, and devices with multi-step breakdown. We propose that small variations in the oxygen/ argon flow ratio result in relevant changes of the oxygen vacancy concentration, which is the key parameter determining the resistive switching behavior. The coexistence of percolative or non-percolative conductive filaments is also discussed. Finally, the hypothesis is verified by means of the temperature dependence of the devices in low resistance state.

Quorum sensing circuit and reactive oxygen species resistance in Deinococcus sp.

Science.gov (United States)

Fernandez-Bunster, G; Gonzalez, C; Barros, J; Martinez, M

2012-12-01

Genus Deinococcus is characterized by an increased resistance toward reactive oxygen species (ROS). The chromosome of five strains belonging to this genus has been sequenced and the presence of a luxS-like gene was deduced from their genome sequences. The aim of this study was to assess if a complete QS circuit is present in Deinococcus sp. and if this QS is associated with ROS. Primers for searching luxS-like gene and the putative receptor gene, namely ai2R, were designed. AI-2 signal production was evaluated by luminescence analysis using Vibrio harveyi BB170 as reporter strain. AI-2 signal was also evaluated by competitive assays using cinnamaldehyde, ascorbic acid, and 3-mercaptopropionic acid as interfering molecules. Potassium tellurite and metronidazole were used as oxidative stressors. A luxS-like gene as well as an ai2R gene was detected in strain UDEC-P1 by PCR. Cell-free supernatant of strain UDEC-P1 culture induced luminescence in V. harveyi BB170, and this property was inhibited with the three interfering molecules. The oxidative stressors metronidazole and potassium tellurite decreased Deinococcus sp. viability, but increased luminescence of the reporter strain. The results demonstrate that both a functional luxS-like gene and a putative receptor for AI-2 signal are present in Deinococcus sp. strain UDEC-P1. This finding also suggests that a complete QS circuit is present in this genus, which could be related to oxidative stress.

The dynamics of ultraviolet-induced oxygen vacancy at the surface of insulating SrTiO{sub 3}(0 0 1)

Energy Technology Data Exchange (ETDEWEB)

Suwanwong, S. [School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Program in General Science Teaching, Faculty of Education, Vongchavalitkul University, Nakhon Ratchasima 30000 (Thailand); Eknapakul, T. [School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Rattanachai, Y. [Department of Applied Physics, Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Nakhon Ratchasima 30000 (Thailand); Masingboon, C. [School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Faculty of Science and Engineering, Kasetsart University, Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon 47000 (Thailand); Rattanasuporn, S.; Phatthanakun, R.; Nakajima, H. [Synchrotron Light Research Institute, Nakhon Ratchasima 30000 (Thailand); King, P.D.C. [SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS (United Kingdom); Hodak, S.K. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Meevasana, W., E-mail: worawat@g.sut.ac.th [School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Thailand Center of Excellence in Physics, CHE, Bangkok 10400 (Thailand)

2015-11-15

Highlights: • The dynamics of UV-induced oxygen vacancy is studied from the change of surface resistance. • The formation of 2DEG at the insulating surface of SrTiO{sub 3} is confirmed by ARPES. • The UV-induced change in resistance responds differently to oxygen/gas exposure. • The behavior of resistance recovery suggests an alternative method of low-pressure sensing. - Abstract: The effect of ultra-violet (UV) irradiation on the electronic structure and the surface resistance of an insulating SrTiO{sub 3}(0 0 1) crystal is studied in this work. Upon UV irradiation, we show that the two-dimensional electron gas (2DEG) emerges at the insulating SrTiO{sub 3} surface and there is a pronounced change in the surface resistance. By combining the observations of the change in valance band and the resistance change under different environments of gas pressure and gas species, we find that UV-induced oxygen vacancies at the surface plays a major role in the resistance change. The dynamic of the resistance change at different oxygen pressures also suggests an alternative method of low-pressure sensing.

Optimization of copper electroplating process applied for microfabrication on flexible polyethylene terephthalate substrate

International Nuclear Information System (INIS)

Le, Nguyen Ngan; Hue Phan, Thi Cam; Le, Anh Duy; Dung Dang, Thi My; Dang, Mau Chien

2015-01-01

Electroplating is an important step in microfabrication in order to increase thickness of undersized parts up to a few micrometers with a low-cost, fast method that is easy to carry out, especially for metals such as copper, nickel, and silver. This important step promotes the development of the fabrication technology of electronic devices on a flexible substrate, also known as flexible electronic devices. Nevertheless, this technology has some disadvantages such as low surface uniformity and high resistivity. In this paper, parameters of copper electroplating were studied, such as the ratio of copper (II) sulfate (CuSO_4) concentration to sulfuric acid (H_2SO_4) concentration and electroplating current density, in order to obtain low resistivity and high surface uniformity of the copper layer. Samples were characterized by scanning electron microscopy (SEM), four-point probe, and surface profiler. The results showed that the sample resistivity could be controlled from about 2.0 to about 3.5 μΩ · cm, and the lowest obtained resistivity was 1.899 μΩ · cm. In addition, surface uniformity of the electroplated copper layer was also acceptable. The thickness of the copper layer was about 10 μm with an error of about 0.5 μm. The most suitable conditions for the electroplating process were CuSO_4 concentration of 0.4 mol l"−"1, H_2SO_4 concentration of 1.0 mol l"−"1, and low electroplating current density of 10–20 mA cm"−"2. All experiments were performed on a flexible polyethylene terephthalate (PET) substrate. (paper)

Steady-state oxygen-solubility in niobium

International Nuclear Information System (INIS)

Schulze, K.; Jehn, H.

1977-01-01

During annealing of niobium in oxygen in certain temperature and pressure ranges steady states are established between the absorption of molecular oxygen and the evaporation of volatile oxides. The oxygen concentration in the niobium-oxygen α-solid solution is a function of oxygen pressure and temperature and has been redetermined in the ranges 10 -5 - 10 -2 Pa O 2 and 2,070 - 2,470 K. It follows differing from former results the equation csub(o) = 9.1 x 10 -6 x sub(po2) x exp (502000/RT) with csub(o) in at.-ppm, sub(po2) in Pa, T in K, R = 8.31 J x mol -1 x K -1 . The existence of steady states is limited to a temperature range from 1870 to 2470 K and to oxygen concentrations below the solubility limit given by solidus and solvus lines in the T-c diagram. In the experiments high-purity niobium wires with a specific electrical ratio rho (273 K)/rho(4.2 K) > 5,000 have been gassed under isothermal-isobaric conditions until the steady state has been reached. The oxygen concentration has been determined analytically by vacuum fusion extraction with platinum-flux technique as well as by electrical residual resistivity measurements at 4.2 K. (orig.) [de

Injections, cocktails and diviners: therapeutic flexibility in the context of malaria elimination and drug resistance in Northeast Cambodia.

Directory of Open Access Journals (Sweden)

Charlotte Gryseels

Full Text Available BACKGROUND: Adherence to effective malaria medication is extremely important in the context of Cambodia's elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia, their illness itineraries often lead them to private pharmacies selling "cocktails" and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits. METHODS: The research design consisted of a mixed methods study, combining qualitative (in-depth interviews and participant observation and quantitative methods (household and cross-sectional survey. RESULTS: Three broad options for malaria treatment were identified: i the public sector; ii the private sector; iii traditional treatment based on divination and ceremonial sacrifice. Treatment choice was influenced by the availability of treatment and provider, perceived side effects and efficacy of treatments, perceived etiology of symptoms, and patient-health provider encounters. Moreover, treatment paths proved to be highly flexible, changing mostly in relation to the perceived efficacy of a chosen treatment. CONCLUSIONS: Despite good availability of anti-malarial treatment in the public health sector, attendance remained low due to both structural and human behavioral factors. The common use and under-dosage of anti-malaria monotherapy in the private sector (single-dose injections, single-day drug cocktails represents a threat not only for individual case management, but also for the regional plan of drug resistance containment and malaria elimination.

Individual coping characteristics, rearing conditions and behavioural flexibility in pigs

NARCIS (Netherlands)

Bolhuis, J.E.; Schouten, W.G.P.; Leeuw, de J.A.; Schrama, J.W.; Wiegant, V.M.

2004-01-01

Several studies suggest that classification of piglets early in life based on the degree of resistance they display in a so-called Backtest may be indicative of their coping style at a later age. In the present study behavioural flexibility was investigated in pigs diverging for Backtest response

Nanoscale Cross-Point Resistive Switching Memory Comprising p-Type SnO Bilayers

KAUST Repository

Hota, Mrinal Kanti

2015-02-23

Reproducible low-voltage bipolar resistive switching is reported in bilayer structures of p-type SnO films. Specifically, a bilayer homojunction comprising SnOx (oxygen-rich) and SnOy (oxygen-deficient) in nanoscale cross-point (300 × 300 nm2) architecture with self-compliance effect is demonstrated. By using two layers of SnO film, a good memory performance is obtained as compared to the individual oxide films. The memory devices show resistance ratio of 103 between the high resistance and low resistance states, and this difference can be maintained for up to 180 cycles. The devices also show good retention characteristics, where no significant degradation is observed for more than 103 s. Different charge transport mechanisms are found in both resistance states, depending on the applied voltage range and its polarity. The resistive switching is shown to originate from the oxygen ion migration and subsequent formation/rupture of conducting filaments.

Tuning resistance states by thickness control in an electroforming-free nanometallic complementary resistance random access memory

Science.gov (United States)

Yang, Xiang; Lu, Yang; Lee, Jongho; Chen, I.-Wei

2016-01-01

Tuning low resistance state is crucial for resistance random access memory (RRAM) that aims to achieve optimal read margin and design flexibility. By back-to-back stacking two nanometallic bipolar RRAMs with different thickness into a complementary structure, we have found that its low resistance can be reliably tuned over several orders of magnitude. Such high tunability originates from the exponential thickness dependence of the high resistance state of nanometallic RRAM, in which electron wave localization in a random network gives rise to the unique scaling behavior. The complementary nanometallic RRAM provides electroforming-free, multi-resistance-state, sub-100 ns switching capability with advantageous characteristics for memory arrays.

Tuning resistance states by thickness control in an electroforming-free nanometallic complementary resistance random access memory

International Nuclear Information System (INIS)

Yang, Xiang; Lu, Yang; Lee, Jongho; Chen, I-Wei

2016-01-01

Tuning low resistance state is crucial for resistance random access memory (RRAM) that aims to achieve optimal read margin and design flexibility. By back-to-back stacking two nanometallic bipolar RRAMs with different thickness into a complementary structure, we have found that its low resistance can be reliably tuned over several orders of magnitude. Such high tunability originates from the exponential thickness dependence of the high resistance state of nanometallic RRAM, in which electron wave localization in a random network gives rise to the unique scaling behavior. The complementary nanometallic RRAM provides electroforming-free, multi-resistance-state, sub-100 ns switching capability with advantageous characteristics for memory arrays

Polymer substrates for flexible photovoltaic cells application in personal electronic system

Science.gov (United States)

Znajdek, K.; Sibiński, M.; Strąkowska, A.; Lisik, Z.

2016-01-01

The article presents an overview of polymeric materials for flexible substrates in photovoltaic (PV) structures that could be used as power supply in the personal electronic systems. Four types of polymers have been elected for testing. The first two are the most specialized and heat resistant polyimide films. The third material is transparent polyethylene terephthalate film from the group of polyesters which was proposed as a cheap and commercially available substrate for the technology of photovoltaic cells in a superstrate configuration. The last selected polymeric material is a polysiloxane, which meets the criteria of high elasticity, is temperature resistant and it is also characterized by relatively high transparency in the visible light range. For the most promising of these materials additional studies were performed in order to select those of them which represent the best optical, mechanical and temperature parameters according to their usage for flexible substrates in solar cells.

The resistivity measurements of Pb-based 1212 superconductors under pressure

International Nuclear Information System (INIS)

Sampath Kumar, T.S.; Subba Raman, T.S.; Gokulnath, K.; Latha, B.; Natarajan, S.

1995-01-01

High pressure resistivity study of (Pb 0.5 Cd 0.5 )Sr 2 (Y 0.7 Ca 0.3 )Cu 2 O 7 compounds, annealed in air and oxygen, has been carried out at room temperature. Both the samples show an initial drop in resistivity up to 20 kb followed by a steady value up to 80 kb. But the rate of drop of resistivity with pressure is sharp for the oxygen annealed 1212-sample, and has the lowest resistivity value above 20 kb. The high pressure results suggest that the (Pb,Cd)-1212 samples are under-doped. (author)

Assessing hafnium on hafnia as an oxygen getter

International Nuclear Information System (INIS)

O'Hara, Andrew; Demkov, Alexander A.; Bersuker, Gennadi

2014-01-01

Hafnium dioxide or hafnia is a wide band gap dielectric used in a range of electronic applications from field effect transistors to resistive memory. In many of these applications, it is important to maintain control over oxygen stoichiometry, which can be realized in practice by using a metal layer, specifically hafnium, to getter oxygen from the adjacent dielectric. In this paper, we employ density functional theory to study the thermodynamic stability of an interface between (100)-oriented monoclinic hafnia and hafnium metal. The nudged elastic band method is used to calculate the energy barrier for migration of oxygen from the oxide to the metal. Our investigation shows that the presence of hafnium lowers the formation energy of oxygen vacancies in hafnia, but more importantly the oxidation of hafnium through the migration of oxygen from hafnia is favored energetically

Surface oxygen vacancy and oxygen permeation flux limits of perovskite ion transport membranes

KAUST Repository

Hunt, Anton

2015-09-01

© 2015 Elsevier B.V. The mechanisms and quantitative models for how oxygen is separated from air using ion transport membranes (ITMs) are not well understood, largely due to the experimental complexity for determining surface exchange reactions at extreme temperatures (>800°C). This is especially true when fuels are present at the permeate surface. For both inert and reactive (fuels) operations, solid-state oxygen surface vacancies (δ) are ultimately responsible for driving the oxygen flux, JO2. In the inert case, the value of δ at either surface is a function of the local PO2 and temperature, whilst the magnitude of δ dictates both the JO2 and the inherent stability of the material. In this study values of δ are presented based on experimental measurements under inert (CO2) sweep: using a permeation flux model and local PO2 measurements, collected by means of a local gas-sampling probe in our large-scale reactor, we can determine δ directly. The ITM assessed was La0.9Ca0.1FeO3-δ (LCF); the relative resistances to JO2 were quantified using the pre-defined permeation flux model and local PO2 values. Across a temperature range from 825°C to 1056°C, δ was found to vary from 0.007 to 0.029 (<1%), safely within material stability limits, whilst the permeate surface exchange resistance dominates. An inert JO2 limit was identified owing to a maximum sweep surface δ, δmaxinert. The physical presence of δmaxinert is attributed to a rate limiting step shift from desorption to associative electron transfer steps on the sweep surface as PO2 is reduced. Permeate surface exchange limitations under non-reactive conditions suggest that reactive (fuel) operation is necessary to accelerate surface chemistry for future work, to reduce flux resistance and push δpast δmaxinert in a stable manner.

Observation of weakly adsorbed oxygen on Y5Ba6Cu11Oy

International Nuclear Information System (INIS)

Kao, Sendjaja; Ng, K.Y.S.

1992-01-01

In the Y-Ba-Cu-O compound, several investigators have observed superconductivity-like phenomena at higher temperatures, some even reaching zero resistance at 250 K. Huang et al. reported an observation of sharp resistivity drops, at least four orders of magnitude at ca. 230 K, in one annealed sample of Eu 1 Ba 2 Cu 3 O 6+x . But the resistance drop disappeared after thermal cycling, although the correlated magnetic anomalies observed in their magnetic measurements persisted for many thermal cycles. Recently, Chen et al reported that the superconductivity-like transition at a temperature above 200 K in their mixed-phase YBaCuO persisted for 29 thermal cycles. The samples were treated by a low-temperature (50-70C) oxygenation process and enclosed in oxygen environment during electrical and magnetic measurements. They also found that this higher-temperature transition could not survive thermal cycling when the sample was in helium atmosphere. The role oxygen plays in their observations is not clear, but they speculated that weakly bonded oxygen atom/atoms are responsible for the high-temperature phase. This observation of T c > 200 K in oxygen environment is recently confirmed by Schonberger et al. in highly oriented multiphase Y-Ba-Cu-O thin film. Here, the authors observed, for the first time, adsorption of weakly bonded oxygen at low temperature (≤250C) by a Y 5 Ba 6 Cu 11 O y sample, using thermogravimetric analysis. The resulting oxygen enriched phase in the surface layers may be attributed to the observation of a superconductivity-like transition at above 200 K

Oxygen defects in Fe-substituted Tl-system superconductors

Institute of Scientific and Technical Information of China (English)

李阳; 曹国辉; 王耘波; 马庆珠; 熊小涛; 陈宁; 马如璋; 郭应焕; 许祝安; 王劲松; 张小俊; 焦正宽; 彭获田; 周思海

1996-01-01

For Fe-doped T1-1223 phase,the excess oxygen defects induced by Fe dopants are studied by means of Hall coefficient,thermogravimetric measurements,Mossbauer spectroscopy,and the model calculation of the effective bond valence.The extra oxygen defects have effects on carrier density and microstructure of the superconductors.In the light doping level of Fe (x=0-0.05),the superconducting transition and carrier density have significant corresponding relation--the zero resistance temperature Tco and carrier densities decrease linearly with Fe dopants increasing.The thermogravimetric measurements show that the Fe3+ ions’ substituting for Cu2+ ions can bring the extra oxygen into the lattice to form extra oxygen defects.The calculation of the effective bond valence shows that the decrease of carrier density originates the strongly localized binding of the extra oxygen defects.The distortion of Cu-O layer induced by the extra oxygen defects decreases the superconductive transition temperature.The microstructure

Resistance switching mechanism of La_0_._8Sr_0_._2MnO_3_−_δ thin films

International Nuclear Information System (INIS)

Luo, X.D.; Gao, R.L.; Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L.; Zhang, H.R; Sun, J.R.

2016-01-01

Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 and oxygen-deficient La_0_._8Sr_0_._2MnO_3_−_δ films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

Effect of Spacecraft Environmental Variables on the Flammability of Fire Resistant Fabrics

Science.gov (United States)

Osorio, A. F.; Fernandez-Pello, C.; Takahashi, S.; Rodriguez, J.; Urban, D. L.; Ruff, G.

2012-01-01

Fire resistant fabrics are used for firefighter, racecar drivers as well as astronaut suits. However, their fire resistant characteristics depend on the environment conditions and require study. Particularly important is the response of these fabrics to elevated oxygen concentration environments and radiant heat from a source such as an adjacent fire. In this work, experiments using two fire resistant fabrics were conducted to study the effect of oxygen concentration, external radiant flux and oxidizer flow velocity in concurrent flame spread. Results show that for a given fabric the minimum oxygen concentration for flame spread depends strongly on the magnitude of the external radiant flux. At increased oxygen concentrations the external radiant flux required for flame spread decreases. Oxidizer flow velocity influences the external radiant flux only when the convective heat flux from the flame has similar values to the external radiant flux. The results of this work provide further understanding of the flammability characteristics of fire resistant fabrics in environments similar to those of future spacecrafts.

Design and control of the oxygen partial pressure of UO2 in TGA using the humidification system

International Nuclear Information System (INIS)

Lee, S.; Knight, T.W.; Roberts, E.

2015-01-01

Highlights: • We focus on measurement of oxygen partial pressure and change of O/M ratio under specific conditions produced by the humidification system. • This shows that the humidification system is stable, accurate, and reliable enough to be used for experiments of the oxygen partial pressure measurement for the oxide fuels. • The humidification system has benefits of easy control and flexibility for producing various oxygen partial pressures with fixed hydrogen gas flow rate. - Abstract: The oxygen to uranium (O/U) ratio of UO 2±x is determined by the oxygen content of the sample and is affected by oxygen partial pressure (pO 2 ) of the surrounding gas. Oxygen partial pressure is controllable by several methods. A common method to produce different oxygen partial pressures is the use of equilibria of different reaction gases. There are two common methods: H 2 O/H 2 reaction and CO 2 /CO reaction. In this work, H 2 O/H 2 reaction using a humidifier was employed and investigated to ensure that this humidification system for oxygen partial pressure is stable and accurate for use in Thermogravimetric Analyzer (TGA) experiments with UO 2 . This approach has the further advantage of flexibility to make a wide range of oxygen partial pressure with fixed hydrogen gas flow rate only by varying temperature of water in the humidifier. The whole system for experiments was constructed and includes the humidification system, TGA, oxygen analyzer, and gas flow controller. Uranium dioxide (UO 2 ) samples were used for experiments and oxygen partial pressure was measured at the equilibrium state of stoichiometric UO 2.0 . Oxygen partial pressures produced by humidification (wet gas) system were compared to the approach using mixed dry gases (without humidification system) to demonstrate that the humidification system provides for more stable and accurate oxygen partial pressure control. This work provides the design, method, and analysis of a humidification system for

Improvement of mechanical reliability by patterned silver/Indium-Tin-Oxide structure for flexible electronic devices

International Nuclear Information System (INIS)

Baek, Kyunghyun; Jang, Kyungsoo; Lee, Youn-Jung; Ryu, Kyungyul; Choi, Woojin; Kim, Doyoung; Yi, Junsin

2013-01-01

We report the effect of silver (Ag)-buffer layer Indium-Tin-Oxide (ITO) film on a polyethylene terephthalate substrate on the electrical, optical and reliable properties for transparent–flexible displays. The electrical and optical characteristics of an ITO-only film and an Ag-layer-inserted ITO film are measured and compared to assess the applicability of the triple layered structure in flexible displays. The sheet resistance, the resistivity and the light transmittance of the ITO-only film were 400 Ω/sq, 1.33 × 10 −3 Ω-cm and 99.2%, while those of the ITO film inserted with a 10 nm thick Ag layer were 165 Ω/sq, 4.78 × 10 −4 Ω-cm and about 97%, respectively. To evaluate the mechanical reliability of the different ITO films, bending tests were carried out. After the dynamic bending test of 900 cycles, the sheet resistance of the ITO film inserted with the Ag layer changed from 154 Ω/sq to 475 Ω/sq, about a 3-time increase but that of the ITO-only film changed from 400 Ω/sq to 61,986 Ω/sq, about 150-time increase. When the radius is changed from 25 mm to 20 mm in the static bending test, the sheet resistance of the ITO-only film changed from 400 to 678.3 linearly whereas that of the Ag-layer inserted ITO film changed a little from 154.4 to 154.9. These results show that Ag-layer inserted ITO film had better mechanical characteristics than the ITO-only film. - Highlights: ► Transparent flexible electrode fabricated on glass substrate. ► Electrode fabricated using vertically-patterned design on glass substrate. ► Optimization of the vertical patterns ► Application of the vertically-patterned electrode in transparent–flexible electronics

Flexible textile-based strain sensor induced by contacts

International Nuclear Information System (INIS)

Zhang, Hui

2015-01-01

In this paper, the contact effects are used as the key sensing element to develop flexible textile-structured strain sensors. The structures of the contact are analyzed theoretically and the contact resistances are investigated experimentally. The electromechanical properties of the textiles are investigated to find the key factors which determine the sensitivity, repeatability, and linearity of the sensor. The sensing mechanism is based on the change of contact resistance induced by the change of the configuration of the textiles. In order to improve the performance of the textile strain sensor, the contact resistance is designed based on the electromechanical properties of the fabric. It can be seen from the results that the performance of the sensor is largely affected by the structure of the contacts, which are determined by the morphology of fiber surface and the structures of the yarn and fabric. (paper)

Fully-flexible supercapacitors using spray-deposited carbon-nanotube films as electrodes

Science.gov (United States)

Lee, Churl Seung; Bae, Joonho

2013-12-01

Fully-flexible carbon-nanotube-based supercapacitors were successfully fabricated using a spray method. For electrodes, multiwalled carbon-nanotube films sprayed on polyethylene terephthalate (PET) substrates were employed. Thin Al films on PET were used as current collectors. The electrolyte was 1 M KNO3. Cyclic voltammetry and galvanostatic charge-discharge measurements on the flexible supercapacitors revealed that the area-specific capacitance was 0.11 mF/cm2. Electrochemical impedance spectroscopy of the supercapacitors resulted in a low internal resistance (3.7 Ω). The energy density and the power density of the flexible supercapacitor were measured to be 3.06 × 10-8 Wh/cm2 and 2.65 × 10-7 W/cm2, respectively. The Bode | z| and phase-angle plots showed that the supercapacitors functioned close to ideal capacitors at the frequencies near 2 kHz. These results indicate that the spray deposition method of carbon nanotubes could be promising for fabricating flexible energy devices or electronics.

Oxygen stoichiometry and its influence on superconductivity in Bi2Sr2CaCu2O8+x

International Nuclear Information System (INIS)

Krishnaraj, P.; Lelovic, M.; Eror, N.G.; Balachandran, U.

1994-01-01

Bi 2 Sr 2 CaCu 2 O 8+x (2212) was synthesized from freeze-dried precursors. The oxygen content of 2212 was determined as a function of temperature and oxygen partial pressure and the variation of Tc with oxygen content was determined. It was found that 2212 without excess oxygen (x = 0) is superconducting. This points to the role of the (Bi-O) ∞ layers as a source for holes in 2212. Four probe resistivity measurements were also performed on 2212. The nature of oxygen intercalation and oxygen removal in 2212 was studied by thermogravimetry and resistivity. It was also found that samples of 2212 with the same oxygen content had different T c 's depending on thermal history. This difference in T c is thought to arise from oxygen occupying different sites in the lattice while maintaining the same total oxygen content

Oxygen vacancy chain and conductive filament formation in hafnia

Science.gov (United States)

Xue, Kan-Hao; Miao, Xiang-Shui

2018-04-01

The stability and aggregation mechanisms of oxygen vacancy chains are studied for hafnia using self-energy corrected density functional theory. While oxygen vacancies tend not to align along the c-axis of monoclinic HfO2, oxygen vacancy chains along a-axis and b-axis are energetically favorable, with cohesive energies of 0.05 eV and 0.03 eV per vacancy, respectively. Nevertheless, with an increase of the cross section area, intensive oxygen vacancy chains become much more stable in hafnia, which yields phase separation into Hf-clusters and HfO2. Compared with disperse single vacancy chains, intensive oxygen vacancy chains made of 4, 6, and 8 single vacancy chains are energetically more favorable by 0.17, 0.20, and 0.30 eV per oxygen vacancy, respectively. On the other hand, while a single oxygen vacancy chain exhibits a tiny electronic energy gap of around 0.5 eV, metallic conduction emerges for the intensive vacancy chain made of 8 single vacancy chains, which possesses a filament cross section area of ˜0.4 nm2. This sets a lower area limit for Hf-cluster filaments from metallic conduction point of view, but in real hafnia resistive RAM devices the cross section area of the filaments can generally be much larger (>5 nm2) for the sake of energy minimization. Our work sets up a bridge between oxygen vacancy ordering and phase separation in hafnia, and shows a clear trend of filament stabilization with larger dimensions. The results could explain the threshold switching phenomenon in hafnia when a small AFM tip was used as the top electrode, as well as the undesired multimode operation in resistive RAM cells with 3 nm-thick hafnia.

Highly flexible indium zinc oxide electrode grown on PET substrate by cost efficient roll-to-roll sputtering process

International Nuclear Information System (INIS)

Park, Yong-Seok; Kim, Han-Ki; Jeong, Soon-Wook; Cho, Woon-Jo

2010-01-01

We have investigated the characteristics of flexible indium zinc oxide (IZO) electrode grown on polyethylene terephthalate (PET) substrates using a specially designed roll-to-roll (RTR) sputtering system for use in flexible optoelectronics. It was found that both electrical and optical properties of the flexible IZO electrode were critically dependent on the DC power and Ar/O 2 flow ratio during the roll-to-roll sputtering process. At optimized conditions (constant working pressure of 3 mTorr, Ar/O 2 flow ratio of Ar at only 30 sccm, DC power 800 W and rolling speed at 0.1 cm/s) the flexible IZO electrode exhibits a sheet resistance of 17.25 Ω/sq and an optical transmittance of 89.45% at 550 nm wavelength. Due to the low PET substrate temperature, which is effectively maintained by cooling drum system, all IZO electrodes showed an amorphous structure regardless of the DC power and Ar/O 2 flow ratio. Furthermore, the IZO electrodes grown at optimized condition exhibited superior flexibility than the conventional amorphous ITO electrodes due to its stable amorphous structure. This indicates that the RTR sputter grown IZO electrode is a promising flexible electrode that can substitute for the conventional ITO electrode, due to its low resistance, high transparency, superior flexibility and fast preparation by the RTR process.

Use of Oxygen Therapies in Wound Healing

DEFF Research Database (Denmark)

Gottrup, Finn; Dissemond, Joachim; Baines, Carol

2017-01-01

Among other things wound healing requires restoration of macro-And microcirculation as essential conditions for healing.1,2 One of the most 'immediate' requirements is oxygen, which is critically important for reconstruction of new vessels and connective tissue and to enable competent resistance...

Accurate calibration of RL shunts for piezoelectric vibration damping of flexible structures

DEFF Research Database (Denmark)

Høgsberg, Jan Becker; Krenk, Steen

2016-01-01

Piezoelectric RL (resistive-inductive) shunts are passive resonant devices used for damping of dominantvibration modes of a flexible structure and their efficiency relies on precise calibration of the shuntcomponents. In the present paper improved calibration accuracy is attained by an extension...

Flexible Bronchoscopy.

Science.gov (United States)

Miller, Russell J; Casal, Roberto F; Lazarus, Donald R; Ost, David E; Eapen, George A

2018-03-01

Flexible bronchoscopy has changed the course of pulmonary medicine. As technology advances, the role of the flexible bronchoscope for both diagnostic and therapeutic indications is continually expanding. This article reviews the historical development of the flexible bronchoscopy, fundamental uses of the flexible bronchoscope as a tool to examine the central airways and obtain diagnostic tissue, and the indications, complications, and contraindications to flexible bronchoscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

Abnormal gas sensing characteristics arising from catalyzed morphological changes of ionsorbed oxygen

International Nuclear Information System (INIS)

Xue Xinyu; Chen Zhaohui; Ma Chunhua; Xing Lili; Chen Yujin; Wang Yanguo; Wang Taihong

2010-01-01

Abnormal gas sensing characteristics are observed at low temperature in uniformly loaded Pt-SnO 2 nanorod gas sensors. The sensors operated at 200 deg. C exhibit opposite variations of resistances, and the change of resistance decreases with increasing ethanol concentration. In contrast, the sensors operated at 300 deg. C show regular behavior and the sensitivity is extremely high. Such behaviors are ascribed to Pt-catalyzed morphological changes of ionsorbed oxygen at low temperature. The present results are the bases for further investigating the effect of ionsorbed oxygen morphologies on gas sensing.

A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals.

Science.gov (United States)

Sangeetha, N M; Gauvin, M; Decorde, N; Delpech, F; Fazzini, P F; Viallet, B; Viau, G; Grisolia, J; Ressier, L

2015-08-07

Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn(4+) doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, (1)H, (13)C and (119)Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 10(3) for oleate ITO to 13 × 10(3)Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry.

ITO-free flexible organic solar cells with printed current collecting grids

NARCIS (Netherlands)

Galagan, Y.O.; Rubingh, J.E.J.M.; Andriessen, H.A.J.M.; Fan, C.C.; Blom, P.W.M.; Veenstra, S.C.; Kroon, J.M.

2011-01-01

The presence of a transparent conductive electrode such as indium tin oxide (ITO) limits the reliability and cost price of organic photovoltaic devices as it is brittle and expensive. Moreover, the relative high sheet resistance of an ITO electrode on flexible substrates limits the maximum width of

Flexible Li-CO{sub 2} batteries with liquid-free electrolyte

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiaofei; Li, Zifan; Chen, Jun [Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin (China)

2017-05-15

Developing flexible Li-CO{sub 2} batteries is a promising approach to reuse CO{sub 2} and simultaneously supply energy to wearable electronics. However, all reported Li-CO{sub 2} batteries use liquid electrolyte and lack robust electrolyte/electrodes structure, not providing the safety and flexibility required. Herein we demonstrate flexible liquid-free Li-CO{sub 2} batteries based on poly(methacrylate)/poly(ethylene glycol)-LiClO{sub 4}-3 wt %SiO{sub 2} composite polymer electrolyte (CPE) and multiwall carbon nanotubes (CNTs) cathodes. The CPE (7.14 x 10{sup -2} mS cm{sup -1}) incorporates with porous CNTs cathodes, displaying stable structure and small interface resistance. The batteries run for 100 cycles with controlled capacity of 1000 mAh g{sup -1}. Moreover, pouch-type flexible batteries exhibit large reversible capacity of 993.3 mAh, high energy density of 521 Wh kg{sup -1}, and long operation time of 220 h at different degrees of bending (0-360 ) at 55 C. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Solid oxide fuel cell cathode infiltrate particle size control and oxygen surface exchange resistance determination

Science.gov (United States)

Burye, Theodore E.

Over the past decade, nano-sized Mixed Ionic Electronic Conducting (MIEC) -- micro-sized Ionic Conducting (IC) composite cathodes produced by the infiltration method have received much attention in the literature due to their low polarization resistance (RP) at intermediate (500-700°C) operating temperatures. Small infiltrated MIEC oxide nano-particle size and low intrinsic MIEC oxygen surface exchange resistance (Rs) have been two critical factors allowing these Nano-Micro-Composite Cathodes (NMCCs) to achieve high performance and/or low temperature operation. Unfortunately, previous studies have not found a reliable method to control or reduce infiltrated nano-particle size. In addition, controversy exists on the best MIEC infiltrate composition because: 1) Rs measurements on infiltrated MIEC particles are presently unavailable in the literature, and 2) bulk and thin film Rs measurements on nominally identical MIEC compositions often vary by up to 3 orders of magnitude. Here, two processing techniques, precursor nitrate solution desiccation and ceria oxide pre-infiltration, were developed to systematically produce a reduction in the average La0.6Sr0.4Co0.8Fe 0.2O3-delta (LSCF) infiltrated nano-particle size from 50 nm to 22 nm. This particle size reduction reduced the SOFC operating temperature, (defined as the temperature where RP=0.1 Ocm 2) from 650°C to 540°C. In addition, Rs values for infiltrated MIEC particles were determined for the first time through finite element modeling calculations on 3D Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) reconstructions of electrochemically characterized infiltrated electrodes.

Uniformly active phase loaded selective catalytic reduction catalysts (V_2O_5/TNTs) with superior alkaline resistance performance

International Nuclear Information System (INIS)

Wang, Haiqiang; Wang, Penglu; Chen, Xiongbo; Wu, Zhongbiao

2017-01-01

Highlights: • VOSO_4 exhibited better synergistic effect with titanate nanotubes than NH_4VO_3. • Ion-exchange reaction occurs between VOSO_4 and titanate nanotubes. • Ion-exchange resulting in uniformly vanadium distribution on titanate nanotubes. • VOSO_4-based catalyst exhibited impressive SCR activity and alkaline resistance. - Abstract: In this work, protonated titanate nanotubes was performed as a potential useful support and different vanadium precursors (NH_4VO_3 and VOSO_4) were used to synthesize deNO_x catalysts. The results showed that VOSO_4 exhibited better synergistic effect with titanate nanotubes than NH_4VO_3, which was caused by the ion-exchange reaction. Then high loading content of vanadium, uniformly active phase distribution, better dispersion of vanadium, more acid sites, better V"5"+/V"4"+ redox cycles and superior oxygen mobility were achieved. Besides, VOSO_4-based titanate nanotubes catalysts also showed enhanced alkaline resistance than particles (P25) based catalysts. It was strongly associated with its abundant acid sites, large surface area, flexible redox cycles and oxygen transfer ability. For the loading on protonated titanate nanotubes, active metal with cation groups was better precursors than anion ones. V_2O_5/TNTs catalyst was a promising substitute for the commercial vanadium catalysts and the work conducted herein provided a useful idea to design uniformly active phase loaded catalyst.

Effectiveness of anode in a solid oxide fuel cell with hydrogen/oxygen mixed gases

Energy Technology Data Exchange (ETDEWEB)

Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Petrovsky, Vladimir; Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States)

2009-06-15

A porous Ni/YSZ cermet in mixed hydrogen and oxygen was investigated for its ability to decrease oxygen activity as the anode of a single chamber SOFC. A cell with a dense 300 {mu}m YSZ electrolyte was operated in a double chamber configuration. The Ni-YSZ anode was exposed to a mixture of hydrogen and oxygen of varying compositions while the cathode was exposed to oxygen. Double chamber tests with mixed gas on the anode revealed voltage oscillations linked to lowered power generation and increased resistance. Resistance measurements of the anode during operation revealed a Ni/NiO redox cycle causing the voltage oscillations. The results of these tests, and future tests of similar format, could be useful in the development of single chamber SOFC using hydrogen as fuel. (author)

Corrosion Resistance of Steels and Armco-Fe in Lead Melt Saturated by Oxygen at 550 degree C

International Nuclear Information System (INIS)

Tsisar, V.P.; Fedirko, V.N.; Eliseeva, O.I.

2007-01-01

Corrosion resistance of stainless steels and Armco-Fe in static lead melt saturated by oxygen at 550 degree C for 2000 h was investigated. It was determined that double oxide layer was formed on the surface of investigated materials. Outer part of double oxide growths from the initial interface 'solid metal/liquid lead' towards the melt and consists of Fe 3 O 4 . Inner part of double oxide based on the matrix is composed of Fe 3 O 4 for Armco-Fe, Fe 1+x Cr 2-x O 4 for martensitic 0.2 C-13 Cr and ferritic-martensitic EP823 steels and Fe 1+x Cr 2- xO 4 +Ni for austenitic 18Cr-10Ni-1Ti. Lead did not penetrate into the matrix of tested materials and was detected only in the scale formed on austenitic steel

Flexible Sensing Electronics for Wearable/Attachable Health Monitoring.

Science.gov (United States)

Wang, Xuewen; Liu, Zheng; Zhang, Ting

2017-07-01

Wearable or attachable health monitoring smart systems are considered to be the next generation of personal portable devices for remote medicine practices. Smart flexible sensing electronics are components crucial in endowing health monitoring systems with the capability of real-time tracking of physiological signals. These signals are closely associated with body conditions, such as heart rate, wrist pulse, body temperature, blood/intraocular pressure and blood/sweat bio-information. Monitoring such physiological signals provides a convenient and non-invasive way for disease diagnoses and health assessments. This Review summarizes the recent progress of flexible sensing electronics for their use in wearable/attachable health monitoring systems. Meanwhile, we present an overview of different materials and configurations for flexible sensors, including piezo-resistive, piezo-electrical, capacitive, and field effect transistor based devices, and analyze the working principles in monitoring physiological signals. In addition, the future perspectives of wearable healthcare systems and the technical demands on their commercialization are briefly discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flexible IZO/Ag/IZO/Ag multilayer electrode grown on a polyethylene terephthalate substrate using roll-to-roll sputtering

Science.gov (United States)

2012-01-01

We investigated the optical, electrical, structural, and surface properties of roll-to-roll [R2R] sputter-grown flexible IZO/Ag/IZO/Ag [IAIA] multilayer films on polyethylene terephthalate substrates as a function of the top indium zinc oxide [IZO] thickness. It was found that the optical transmittance of the IAIA multilayer was significantly influenced by the top IZO layer thickness, which was grown on identical AIA multilayers. However, the sheet resistance of the IAIA multilayer was maintained between the range 5.01 to 5.1 Ω/square regardless of the top IZO thickness because the sheet resistance of the IAIA multilayer was mainly dependent on the thickness of the Ag layers. Notably, the optimized IAIA multilayer had a constant resistance change (ΔR/R0) under repeated outer bending tests with a radius of 10 mm. The mechanical integrity of the R2R-sputtered IAIA multilayer indicated that hybridization of an IZO and Ag metal layer is a promising flexible electrode scheme for the next-generation flexible optoelectronics. PMID:22222144

Hyperbaric oxygen therapy and mechanical resistence of the colonics anastomosis in rats with peritonitis Oxigenoterapia hiperbárica e resistência mecânica das anastomoses cólicas em ratos com peritonite

Directory of Open Access Journals (Sweden)

Antonio Angelo Rocha

2010-08-01

Full Text Available PURPOSE: To analyze the effects of hyperbaric oxygen therapy (HBO on the mechanical resistance of anastomosis performed in rats' distal colon presenting peritonitis induced by ligature and cecal punction using the Total Energy Rupture biomechanical test (ETR. METHODS: It was used 45 rats divided into three groups of 15 animals each. In Control Group (CG, it was performed anastomosis in distal colon without peritonitis. In Peritonitis Group (PG, it was performed anastomosis six hours after the induction of peritonitis by ligature and cecal punction. In Hyperbaric Chamber Group (HCG, it was performed six hours after the induction of peritonitis by ligature and cecal punction. The animals on CG and PG were kept at place air while the animals on HCG were placed on an experimental hyperbaric chamber in order to inhale oxygen at 100%, two absolute atmospheres, for 120 minutes, for four consecutive days. Euthanasia took place on the fifth day of the experiment. All the animals underwent to Total Energy Rupture Biomechanical Resistance test (ETR. Total Energy Rupture was defined as the necessary internal energy stored up to promote the colon rupture after an external traction force imposition. RESULTS: The Peritonitis Group presents smaller average ETR than Control Group. There was no statistical difference between Peritonitis Group and Hyberbaric Chamber Group. CONCLUSION: Hyperbaric oxygen therapy did not alter the mechanical resistance of anastomosis performed in distal colon of rats under the presence of peritonitis induced by ligature and cecal puncture.OBJETIVO: Analisar o efeito da oxigenoterapia hiperbárica (HBO sobre a resistência mecânica de anastomoses realizadas em cólon distal de ratos na presença de peritonite induzida por ligadura e punção cecal utilizando o teste biomecânico de Energia Total de Ruptura (ETR. MÉTODOS: Foram utilizados 45 ratos distribuídos em três grupos de 15 animais. No Grupo Controle (GC, realizou

Investigations of carbon nanotubes and polyacrylonitrile composites for flexible textronics

Science.gov (United States)

Sowiński, J.; Wróblewski, G.; Janczak, D.; Jakubowska, M.

2017-08-01

Thin composite layers based on polyacrylonitrile (PAN) and carbon nanotubes (CNT) were fabricated by means of spray coating with pneumatic atomization. Research was conducted to achieve transparent and flexible electrodes. Prepared suspensions in different proportions of functional phase provided good dispersion quality of CNTs and the stability. The carbon nanotubes were dispersed in dimethylformamide and then added to polyacrylonitrile solution. Suspension was sprayed onto Polyethylene terephthalate (PET) foil. After thermal treatment, samples were mechanically and electrically tested. Thanks to carbon nanomaterials used in prepared coatings, high electrical conductivity and mechanical resistance was observed. Use of a polyacrylonitrile guarantee the flexibility of electrodes and high potential in integration with polyacrylonitrile based fabrics.

SIRT1 attenuates palmitate-induced endoplasmic reticulum stress and insulin resistance in HepG2 cells via induction of oxygen-regulated protein 150

Science.gov (United States)

Jung, T.W.; Lee, K.T.; Lee, M.W.; Ka, K.H.

2012-01-01

Endoplasmic reticulum (ER) stress has been implicated in the pathology of type 2 diabetes mellitus (T2DM). Although SIRT1 has a therapeutic effect on T2DM, the mechanisms by which SIRT1 ameliorates insulin resistance (IR) remain unclear. In this study, we investigated the impact of SIRT1 on palmitate-induced ER stress in HepG2 cells and its underlying signal pathway. Treatment with resveratrol, a SIRT1 activator significantly inhibited palmitate-induced ER stress, leading to the protection against palmitate-induced ER stress and insulin resistance. Resveratrol and SIRT1 overexpression induced the expression of oxygen-regulated protein (ORP) 150 in HepG2 cells. Forkhead box O1 (FOXO1) was involved in the regulation of ORP150 expression because suppression of FOXO1 inhibited the induction of ORP150 by SIRT1. Our results indicate a novel mechanism by which SIRT1 regulates ER stress by overexpression of ORP150, and suggest that SIRT1 ameliorates palmitate-induced insulin resistance in HepG2 cells via regulation of ER stress.

Analysing impact of oxygen and water exposure on roll-coated organic solar cell performance using impedance spectroscopy

DEFF Research Database (Denmark)

Arredondo, B.; Romero, B.; Beliatis, M. J.

2018-01-01

In this work we study the degradation of roll-coated flexible inverted organic solar cells in different atmospheres. We demonstrate that impedance spectroscopy is a powerful tool for elucidating degradation mechanisms; it is used here to distinguish the different degradation mechanisms due to water...... and oxygen. Identical cells were exposed to different accelerated degradation environments using water only, oxygen only, and both water and oxygen simultaneously, all of them enhanced with UV light. The photocurrent is dramatically reduced in the oxygen-degraded samples. Impedance measurements indicate...... of degradation differs for the water and oxygen degraded samples. While oxygen + UV light decreases the conductivity of the PEDOT:PSS layer, water + UV light changes the PEDOT:PSS work function inducing a depletion region at the anode....

Electrochemical characteristics of flexible micro supercapacitors with reduced graphene oxide-carbon nanotubes composite electrodes

Science.gov (United States)

Yang, Kyungwhan; Cho, Kyoungah; Kim, Sangsig

2018-06-01

In this study, we fabricate solid-state flexible micro-supercapacitors (MSCs) with reduced graphene oxide-carbon nanotube (rGO-CNT) composite electrodes and investigate the electrochemical characteristics by comparing with those of an MSC with rGO electrodes. Regarding the resistance-capacitance time constant and IR drop, the addition of CNTs into the rGO electrodes shows a significant effect owing to both the decrease in the resistance and the increase in the permeability of the electrolytes. Compared to the rGO MSCs, the rGO-CNT MSCs show an excellent areal capacitance of 2.6 mF/cm2, a smaller IR drop of 11 mV, a lower RC time constant of 6 ms, and faster charging/discharging rates with a high scan rate ability up to 100 V/s. The mechanical stability of the flexible rGO-CNT MSCs is verified by 1000 bending cycles. In addition, the electrochemical characteristics of the flexible rGO-CNT MSCs are maintained regardless of the MSC array type.

Inhibition of fungal growth with extreme low oxygen levels

DEFF Research Database (Denmark)

Nielsen, Per Væggemose; Haasum, Iben

1998-01-01

Fungal spoilage of foods is effectively controlled by removal of oxygen from the package, especially if this is combined with elevated carbon dioxide (CO2) levels. However, great uncertainty exist on just how low the residual oxygen levels in the package must be especially when carbon dioxide lev...... food with low CO2 levels. Active packaging with oxygen absorbers may be considered for these products. The packaging solution must also reflect the micro flora of the product.......Fungal spoilage of foods is effectively controlled by removal of oxygen from the package, especially if this is combined with elevated carbon dioxide (CO2) levels. However, great uncertainty exist on just how low the residual oxygen levels in the package must be especially when carbon dioxide...... Penicillia and Aspergilli were also inhibited by oxygen levels less than 0.5%, but less than 0.01% was required to efficiently inhibit these fungi. Most resistant to very low oxygen levels was the Fusarium species.These results shows that very low oxygen levels are required to avoid fungal growth in package...

Development of flexible array tactile sensors

DEFF Research Database (Denmark)

Drimus, Alin; Marian, Nicolae; Bilberg, Arne

2010-01-01

time data acquisition system scans all the cells and converts electrical resistance to tactile pressure maps. We validate that this information can be used to improve grasping and perform object recognition. Key words: piezoresistivity, tactile, sensor, pressure, robotics......In this paper we describe the development of an array tactile sensor for use in robotic grippers based on a flexible piezoresistive material. We start by comparing different cell structures in terms of output characteristics and we construct an array of cells in a row and columns layout. A real...

Low-cost, flexible battery packaging materials

Science.gov (United States)

Jansen, Andrew N.; Amine, Khalil; Newman, Aron E.; Vissers, Donald R.; Henriksen, Gary L.

2002-03-01

Considerable cost savings can be realized if the metal container used for lithium-based batteries is replaced with a flexible multi-laminate containment commonly used in the food packaging industry. This laminate structure must have air, moisture, and electrolyte barrier capabilities, be resistant to hydrogen-fluoride attack, and be heat-sealable. After extensive screening of commercial films, the polyethylene and polypropylene classes of polymers were found to have an adequate combination of mechanical, permeation, and seal-strength properties. The search for a better film and adhesive is ongoing.

Enhancing wind turbines efficiency with passive reconfiguration of flexible blades

Science.gov (United States)

Cognet, Vincent P. A.; Thiria, Benjamin; Courrech Du Pont, Sylvain; MSC Team; PMMH Team

2015-11-01

Nature provides excellent examples where flexible materials are advantageous in a fluid stream. By folding, leaves decrease the drag caused by air stream; and birds' flapping is much more efficient with flexible wings. Motivated by this, we investigate the effect of flexible blades on the performance of a wind turbine. The effect of chordwise flexible blades is studied both experimentally and theoretically on a small wind turbine in steady state. Four parameters are varied: the wind velocity, the resisting torque, the pitch angle, and the blade's bending modulus. We find an optimum efficiency with respect to the bending modulus. By tuning our four parameters, the wind turbine with flexible blades has a high-efficiency range significantly larger than rigid blades', and, furthermore enhances the operating range. These results are all the more important as one of the current issues concerning wind turbines is the enlargement of their operating range. To explain these results, we propose a simple two-dimensional model by discretising the blade along the radius. We take into account the variation of drag and lift coefficients with the bending ability. This model matches experimental observations and demonstrates the contribution of the reconfiguration of the blade. Matiere et Systemes Complexes.

Activated carbon oxygen content influence on water and surfactant adsorption.

Science.gov (United States)

Pendleton, Phillip; Wu, Sophie Hua; Badalyan, Alexander

2002-02-15

This research investigates the adsorption properties of three activated carbons (AC) derived from coconut, coal, and wood origin. Each carbon demonstrates different levels of resistance to 2 M NaOH treatment. The coconut AC offers the greatest and wood AC the least resistance. The influence of base treatment is mapped in terms of its effects on specific surface area, micropore volume, water adsorption, and dodecanoic acid adsorption from both water and 2 M NaOH solution. A linear relationship exists between the number of water molecules adsorbed at the B-point of the water adsorption isotherm and the oxygen content determined from elemental analysis. Surfactant adsorption isotherms from water and 2 M NaOH indicate that the AC oxygen content effects a greater dependence on affinity for surfactant than specific surface area and micropore volume. We show a linear relationship between the plateau amount of surfactant adsorbed and the AC oxygen content in both water and NaOH phases. The higher the AC oxygen content, the lower the amount of surfactant adsorbed. In contrast, no obvious relationship could be drawn between the surfactant amount adsorbed and the surface area.

Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

International Nuclear Information System (INIS)

Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Liao, Liangsheng; Sun, Baoquan; Zhang, Ke-Qin

2015-01-01

Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq −1 , a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A −1 , demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices. (paper)

Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

Science.gov (United States)

Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Zhang, Ke-Qin; Liao, Liangsheng; Sun, Baoquan

2015-10-01

Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq-1, a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A-1, demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices.

Novel solid oxide cells with SrCo0.8Fe0.1Ga0.1O3-δ oxygen electrode for flexible power generation and hydrogen production

Science.gov (United States)

Meng, Xiuxia; Shen, Yichi; Xie, Menghan; Yin, Yimei; Yang, Naitao; Ma, Zi-Feng; Diniz da Costa, João C.; Liu, Shaomin

2016-02-01

This work investigates the performance of solid oxide cells as fuel cells (SOFCs) for power production and also as electrolysis cells (SOECs) for hydrogen production. In order to deliver this dual mode flexible operation system, a novel perovskite oxide based on Ga3+ doped SrCo0.8Fe0.1Ga0.1O3-δ (SCFG) is synthesized via a sol-gel method. Its performance for oxygen electrode catalyst was then evaluated. Single solid oxide cell in the configuration of Ni-YSZ|YSZ|GDC|SCFG is assembled and tested in SOFC or SOEC modes from 550 to 850 °C with hydrogen as the fuel or as the product, respectively. GDC is used to avoid the reaction between the electrolyte YSZ and the cobalt-based electrode. Under SOFC mode, a maximum power density of 1044 mW cm-2 is obtained at 750 °C. Further, the cell delivers a stable power output of 650 mW cm-2 up to 125 h at 0.7 V. In the electrolysis mode, when the applied voltage is controlled at 2 V, the electrolysis current density reaches 3.33 A cm-2 at 850 °C with the hydrogen production rate up to 22.9 mL min-1 cm-2 (STP). These results reveal that SCFG is a very promising oxygen electrode material for application in both SOFC and SOEC.

Oxygen storage capacity and structural flexibility of LuFe2O4+x (0≤x≤0.5)

Science.gov (United States)

Hervieu, M.; Guesdon, A.; Bourgeois, J.; Elkaïm, E.; Poienar, M.; Damay, F.; Rouquette, J.; Maignan, A.; Martin, C.

2014-01-01

Combining functionalities in devices with high performances is a great challenge that rests on the discovery and optimization of materials. In this framework, layered oxides are attractive for numerous purposes, from energy conversion and storage to magnetic and electric properties. We demonstrate here the oxygen storage ability of ferroelectric LuFe2O4+x within a large x range (from 0 to 0.5) and its cycling possibility. The combination of thermogravimetric analyses, X-ray diffraction and transmission electron microscopy evidences a complex oxygen intercalation/de-intercalation process with several intermediate metastable states. This topotactic mechanism is mainly governed by nanoscale structures involving a shift of the cationic layers. The ferrite is highly promising because absorption begins at a low temperature (), occurs in a low oxygen pressure and the uptake of oxygen is reversible without altering the quality of the crystals. The storage/release of oxygen coupled to the transport and magnetic properties of LnFe2O4 opens the door to new tunable multifunctional applications.

Graphene-Based Flexible and Transparent Tunable Capacitors

OpenAIRE

Man, Baoyuan; Xu, Shicai; Jiang, Shouzheng; Liu, Aihua; Gao, Shoubao; Zhang, Chao; Qiu, Hengwei; Li, Zhen

2015-01-01

We report a kind of electric field tunable transparent and flexible capacitor with the structure of graphene-Bi1.5MgNb1.5O7 (BMN)-graphene. The graphene films with low sheet resistance were grown by chemical vapor deposition. The BMN thin films were fabricated on graphene by using laser molecular beam epitaxy technology. Compared to BMN films grown on Au, the samples on graphene substrates show better quality in terms of crystallinity, surface morphology, leakage current, and loss tangent. By...

Water based, solution-processable, transparent and flexible graphene oxide composite as electrodes in organic solar cell application

International Nuclear Information System (INIS)

Lima, L F; Matos, C F; Gonçalves, L C; Roman, L S; Salvatierra, R V; Zarbin, A J G; Cava, C E

2016-01-01

In this work we propose an easy method to achieve a conductive, transparent and flexible graphene oxide (GO)-based composite thin film from an aqueous dispersion. We investigated the blend ratio between GO and the conjugated polymer poly(3,4–ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by comparing the thin film optical transmittance, sheet resistance, morphology and mechanical stability. It was found that reasonable values of transmittance and resistivity coupled with its excellent flexibility – the conductivity remains almost the same even after 1000 bends cycles – make this composite very attracting for flexible optoelectronic applications. Thus, these films were used as transparent electrodes in a bilayer structured organic solar cell and the device architecture PET/GO:PEDOT/F8T2/C 60 /Al could reach a power conversion efficiency around 1.10%. This result presents a better performance compared with pristine PEDOT produced with similar parameters. (paper)

A distributed chemosensory circuit for oxygen preference in C. elegans.

Directory of Open Access Journals (Sweden)

Andy J Chang

2006-09-01

Full Text Available The nematode Caenorhabditis elegans has complex, naturally variable behavioral responses to environmental oxygen, food, and other animals. C. elegans detects oxygen through soluble guanylate cyclase homologs (sGCs and responds to it differently depending on the activity of the neuropeptide receptor NPR-1: npr-1(lf and naturally isolated npr-1(215F animals avoid high oxygen and aggregate in the presence of food; npr-1(215V animals do not. We show here that hyperoxia avoidance integrates food with npr-1 activity through neuromodulation of a distributed oxygen-sensing network. Hyperoxia avoidance is stimulated by sGC-expressing oxygen-sensing neurons, nociceptive neurons, and ADF sensory neurons. In npr-1(215V animals, the switch from weak aerotaxis on food to strong aerotaxis in its absence requires close regulation of the neurotransmitter serotonin in the ADF neurons; high levels of ADF serotonin promote hyperoxia avoidance. In npr-1(lf animals, food regulation is masked by increased activity of the oxygen-sensing neurons. Hyperoxia avoidance is also regulated by the neuronal TGF-beta homolog DAF-7, a secreted mediator of crowding and stress responses. DAF-7 inhibits serotonin synthesis in ADF, suggesting that ADF serotonin is a convergence point for regulation of hyperoxia avoidance. Coalitions of neurons that promote and repress hyperoxia avoidance generate a subtle and flexible response to environmental oxygen.

Heat resistant/radiation resistant cable and incore structure test device for FBR type reactor

International Nuclear Information System (INIS)

Tanimoto, Hajime; Shiono, Takeo; Sato, Yoshimi; Ito, Kazumi; Sudo, Shigeaki; Saito, Shin-ichi; Mitsui, Hisayasu.

1995-01-01

A heat resistant/radiation resistant coaxial cable of the present invention comprises an insulation layer, an outer conductor and a protection cover in this order on an inner conductor, in which the insulation layer comprises thermoplastic polyimide. In the same manner, a heat resistant/radiation resistant power cable has an insulation layer comprising thermoplastic polyimide on a conductor, and is provided with a protection cover comprising braid of alamide fibers at the outer circumference of the insulation layer. An incore structure test device for an FBR type reactor comprises the heat resistant/radiation resistant coaxial cable and/or the power cable. The thermoplastic polyimide can be extrusion molded, and has excellent radiation resistant by the extrusion, as well as has high dielectric withstand voltage, good flexibility and electric characteristics at high temperature. The incore structure test device for the FBR type reactor of the present invention comprising such a cable has excellent reliability and durability. (T.M.)

Should flexible ureteroscope be added to our armamentarium to treat stone disease?

Directory of Open Access Journals (Sweden)

Anand Dharaskar

2008-01-01

Full Text Available The field of Urology in Medicine has witnessed tremendous advancement in technology and in accordance with it. Endourology has taken a leap ahead in terms of stone management. Most of the stones could be treated with semi-rigid ureteroscopy, percutaneous nephrolithotomy (PNL and ESWL and some would need Flexible ureteroscopy. Flexible ureteroscopy has been primarily indicated to treat ESWL resistant renal stones but with changes in the technology of incorporating secondary active deflection and availability of laser fibres, its horizon for indications to treat stones is being widened. Though Flexible ureteroscopy is being used to treat stones of various sizes and locations, its cost effectiveness is debatable. Should it be used ubiquitously to treat stones amenable to PNL or ESWL is a big question we need to answer. As of now true indications of Flexible ureteroscopy are limited and there is an urgent need for a randomized trial to compare its efficacy with ESWL and PNL for renal and upper ureteric stones.

Full densification of inkjet-printed copper conductive tracks on a flexible substrate utilizing a hydrogen plasma sintering

Science.gov (United States)

Kwon, Young-Tae; Lee, Young-In; Kim, Seil; Lee, Kun-Jae; Choa, Yong-Ho

2017-02-01

Low temperature sintering techniques are crucial in developing flexible printed electronics. In this work, we demonstrate a novel hydrogen plasma sintering method that achieves a full reduction and densification of inkjet-printed patterns using a copper complex ion ink. After inkjet printing on polyethylene terephthalate (PET) substrates, both hydrogen plasma and conventional hydrogen thermal treatment were employed to compare the resulting microstructures, electrical properties and anti-oxidation behavior. The plasma treated pattern shows a fully densified microstructure with a resistivity of 3.23 μΩ cm, while the thermally treated pattern shows a relatively poor microstructure and high resistivity. In addition, the hydrogen plasma-treated copper pattern retains its electrical resistivity for one month without any significant decrease. This novel hydrogen plasma sintering technique could be used to produce conductive patterns with excellent electrical properties, allowing for highly reliable flexible printed electronics.

Solution-processed flexible NiO resistive random access memory device

Science.gov (United States)

Kim, Soo-Jung; Lee, Heon; Hong, Sung-Hoon

2018-04-01

Non-volatile memories (NVMs) using nanocrystals (NCs) as active materials can be applied to soft electronic devices requiring a low-temperature process because NCs do not require a heat treatment process for crystallization. In addition, memory devices can be implemented simply by using a patterning technique using a solution process. In this study, a flexible NiO ReRAM device was fabricated using a simple NC patterning method that controls the capillary force and dewetting of a NiO NC solution at low temperature. The switching behavior of a NiO NC based memory was clearly observed by conductive atomic force microscopy (c-AFM).

Species specificity of resistance to oxygen diffusion in thin cuticular membranes from amphibious plants

DEFF Research Database (Denmark)

Frost-Christensen, Henning; Jørgensen, Lise Bolt; Floto, Franz

2003-01-01

oxygen, diffusion, cuticula, amphibious plants, Hygrophila, Berula, Lobelia, Mentha, Potamogeton, Veronica, aquatic plants, submerged plants......oxygen, diffusion, cuticula, amphibious plants, Hygrophila, Berula, Lobelia, Mentha, Potamogeton, Veronica, aquatic plants, submerged plants...

Electrolytic production of metals using a resistant anode

Science.gov (United States)

Tarcy, G.P.; Gavasto, T.M.; Ray, S.P.

1986-11-04

An electrolytic process is described comprising evolving oxygen on an anode in a molten salt, the anode comprising an alloy comprising a first metal and a second metal, both metals forming oxides, the oxide of the first metal being more resistant than the second metal to attack by the molten salt, the oxide of the second metal being more resistant than the first metal to the diffusion of oxygen. The electrode may also be formed of CuAlO[sub 2] and/or Cu[sub 2]O. 2 figs.

Self-Powered, Flexible, and Solution-Processable Perovskite Photodetector Based on Low-Cost Carbon Cloth.

Science.gov (United States)

Sun, Haoxuan; Lei, Tianyu; Tian, Wei; Cao, Fengren; Xiong, Jie; Li, Liang

2017-07-01

Flexible perovskite photodetectors are usually constructed on indium-tin-oxide-coated polymer substrates, which are expensive, fragile, and not resistant to high temperature. Herein, for the first time, a high-performance flexible perovskite photodetector is fabricated based on low-cost carbon cloth via a facile solution processable strategy. In this device, perovskite microcrystal and Spiro-OMeTAD (hole transporting material) blended film act as active materials for light detection, and carbon cloth serves as both a flexible substrate and a conductive electrode. The as-fabricated photodetector shows a broad spectrum response from ultraviolet to near-infrared light, high responsivity, fast response speed, long-term stability, and self-powered capability. Flexible devices show negligible degradation after several tens of bending cycles and at the extremely bending angle of 180°. This work promises a new technique to construct flexible, high-performance photodetectors with low cost and self-powered capability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressurized oxy-coal combustion: Ideally flexible to uncertainties

International Nuclear Information System (INIS)

Zebian, Hussam; Mitsos, Alexander

2013-01-01

Simultaneous multi-variable gradient-based optimization with multi-start is performed on a 300 MWe wet-recycling pressurized oxy-coal combustion process with carbon capture and sequestration, subject to uncertainty in fuel, ambient conditions, and other input specifications. Two forms of flue gas thermal recovery are studied, a surface heat exchanger and a direct contact separation column. Optimization enables ideal flexibility in the processes: when changing the coal utilized, the performance is not compromised compared to the optimum performance of a process specifically designed for that coal. Similarly, the processes are immune to other uncertainties like ambient conditions, air flow, slurry water flow, atomizer stream flow and the oxidizer stream oxygen purity. Consequently, stochastic programming is shown to be unnecessary. Close to optimum design, the processes are also shown to be insensitive towards design variables such as the areas of the feedwater heaters. Recently proposed thermodynamic criteria are used as embedded design specifications in the optimization process, rendering it faster and more robust. - Highlights: • Proposed formulation to assess the flexibility of power generation processes facing uncertainties. • Obtained ideal flexibility of pressurized oxy-coal combustion with respect to coal type. • Performance of processes under uncertainty match performance of optimal processes for specific set of inputs. • Stochastic programming is not required and instead hierarchic optimization is utilized

Boron nitride nanosheets as oxygen-atom corrosion protective coatings

International Nuclear Information System (INIS)

Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

2014-01-01

The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion

Early differences in metabolic flexibility between obesity-resistant and obesity-prone mice

Czech Academy of Sciences Publication Activity Database

Bardová, Kristina; Horáková, Olga; Janovská, Petra; Hansíková, Jana; Kůs, Vladimír; van Schothorst, E. M.; Hoevenaars, F.P.M.; Uil, M.; Hensler, Michal; Keijer, J.; Kopecký, Jan

2016-01-01

Roč. 124, May (2016), s. 163-170 ISSN 0300-9084 R&D Projects: GA MŠk(CZ) 7E10059; GA ČR(CZ) GB14-36804G Institutional support: RVO:67985823 Keywords : indirect calorimetry * glucose tolerance * weaning * C57BL/6J mice * A/J mice * metabolic flexibility Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 3.112, year: 2016

Effect of 7 days of exercise on exogenous carbohydrate oxidation and insulin resistance in children with obesity.

Science.gov (United States)

Chu, Lisa; Morrison, Katherine M; Riddell, Michael C; Raha, Sandeep; Timmons, Brian W

2018-07-01

The capacity to match carbohydrate (CHO) oxidation with CHO availability (deemed metabolic flexibility (MetFlex)) may be important for type 2 diabetes prevention. In adults, impaired MetFlex is associated with insulin resistance (IR), which can be improved with as little as 7 days of exercise. Whether this occurs similarly in children is unknown. We hypothesized that 7 consecutive days of exercise would improve MetFlex and IR in children with obesity. Twelve children (8 boys, 4 girls) completed 2 study visits before (PRE) and 2 study visits after (POST) exercise training. At visit 1, fasting blood was collected, and anthropometry and maximal oxygen uptake were assessed. At visit 2, a 13 C-enriched CHO drink was ingested before exercise (3 × 20 min) at ∼59% maximal oxygen uptake. Exogenous CHO oxidative efficiency, used as a surrogate measurement of MetFlex, was calculated from breath samples. During training, participants alternated between continuous and high-intensity interval cycling sessions at home under supervision. In spite of good training adherence, there was no improvement in MetFlex (PRE: 20.7% ± 1.8%, POST: 18.9% ± 4.9%, p = 0.22) or homeostasis model assessment of insulin resistance (PRE: 8.7 ± 4.6, POST: 8.1 ± 6.0, p = 0.51). Future research should investigate exercise volume, sex, and pubertal effects on the early responsiveness of MetFlex to exercise therapy.

Hyperbaric oxygen in the treatment of a diabetic foot ulcer.

LENUS (Irish Health Repository)

Davenport, Colin

2011-02-01

Although simultaneous pancreas and kidney transplant improves most complications of type 1 diabetes, suppression of the immune system increases the risk for infection. The authors report the case of a patient who, despite receiving a simultaneous pancreas and kidney transplant, subsequently developed neuro-ischemic ulcers of his right foot requiring repeated amputations. He then developed an infected ulcer of his remaining right big toe, with significant implications for his mobility. This ulcer proved resistant to multiple courses of antibiotics and care in a specialist foot clinic but resolved completely following a course of hyperbaric oxygen therapy. The role of hyperbaric oxygen in diabetic foot ulcers is not yet fully established but should be considered in resistant cases with vascular insufficiency and a significant infective component.

Hyperbaric oxygen in the treatment of a diabetic foot ulcer.

LENUS (Irish Health Repository)

Davenport, Colin

2012-02-01

Although simultaneous pancreas and kidney transplant improves most complications of type 1 diabetes, suppression of the immune system increases the risk for infection. The authors report the case of a patient who, despite receiving a simultaneous pancreas and kidney transplant, subsequently developed neuro-ischemic ulcers of his right foot requiring repeated amputations. He then developed an infected ulcer of his remaining right big toe, with significant implications for his mobility. This ulcer proved resistant to multiple courses of antibiotics and care in a specialist foot clinic but resolved completely following a course of hyperbaric oxygen therapy. The role of hyperbaric oxygen in diabetic foot ulcers is not yet fully established but should be considered in resistant cases with vascular insufficiency and a significant infective component.

Nanowire surface fastener fabrication on flexible substrate

Science.gov (United States)

Toku, Yuhki; Uchida, Keita; Morita, Yasuyuki; Ju, Yang

2018-07-01

The market for wearable devices has increased considerably in recent years. In response to this demand, flexible electronic circuit technology has become more important. The conventional bonding technology in electronic assembly depends on high-temperature processes such as reflow soldering, which result in undesired thermal damages and residual stress at a bonding interface. In addition, it exhibits poor compatibility with bendable or stretchable device applications. Therefore, there is an urgent requirement to attach electronic parts on printed circuit boards with good mechanical and electrical properties at room temperature. Nanowire surface fasteners (NSFs) are candidates for resolving these problems. This paper describes the fabrication of an NSF on a flexible substrate, which can be used for room temperature conductive bonding. The template method is used for preparing high-density nanowire arrays. A Cu thin film is layered on the template as the flexible substrate. After etching the template, a Cu NSF is obtained on the Cu film substrate. In addition, the electrical and mechanical properties of the Cu NSF are studied under various fabrication conditions. The Cu NSF exhibits high shear adhesion strength (∼234 N cm‑2) and low contact resistivity (2.2 × 10‑4 Ω cm2).

Ultraviolet photodetection of flexible ZnO nanowire sheets in polydimethylsiloxane polymer

OpenAIRE

Jinzhang Liu; Nunzio Motta; Soonil Lee

2012-01-01

Summary ZnO nanowires are normally exposed to an oxygen atmosphere to achieve high performance in UV photodetection. In this work we present results on a UV photodetector fabricated using a flexible ZnO nanowire sheet embedded in polydimethylsiloxane (PDMS), a gas-permeable polymer, showing reproducible UV photoresponse and enhanced photoconduction. PDMS coating results in a reduced response speed compared to that of a ZnO nanowire film in air. The rising speed is slightly reduced, while the ...

On flexibility

OpenAIRE

Weiss, Christoph R.; Briglauer, Wolfgang

2000-01-01

By building on theoretical work by Mills and Schumann (1985) and Ungern-Sternberg (1990) this paper provides evidence on the determinants of two dimensions of flexibility, the flexibility in adjusting aggregate output over time (tactical flexibility) as well as the ability to switch quickly between products (operational flexibility). Econometric analysis of a sample of 40.000 farms in Upper-Austria for the period 1980 to 1990 suggests that larger full-time farms operated by younger, better ed...

Oxygen-doped Sb{sub 4}Te phase change films for high-temperature data retention and low-power application

Energy Technology Data Exchange (ETDEWEB)

Hu, Yifeng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); School of Mathematics and Physics, Jiangsu Teachers University of Technology, Changzhou 213001 (China); Sun, Mingcheng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China)

2013-02-25

Highlights: Black-Right-Pointing-Pointer O-doped Sb{sub 4}Te phase-change films were reported. Black-Right-Pointing-Pointer The amorphous-to-crystalline transitions of O-doped Sb{sub 4}Te films were studied. Black-Right-Pointing-Pointer By doping oxygen, the stability of Sb{sub 4}Te films is improved greatly. Black-Right-Pointing-Pointer The resistance of the Sb{sub 4}Te films increases by doping oxygen. - Abstract: The amorphous-to-crystalline transitions of oxygen-doped Sb{sub 4}Te (STO) films are investigated by in situ film resistance measurements. The crystalline temperature and resistance of the oxygen-doped films increase. The analysis of X-ray diffractomer (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that the films with doping of a small amount of oxygen atoms can refine the grain size and form oxide, improving the resistance and thermal stability of phase change films. Excessive oxygen in Sb{sub 4}Te will make Te separate, resulting in deteriorating the stability. As a result, STO2 film has the relatively high activation energy for crystallization. The 10-year lifetime is raised from 29 Degree-Sign C of undoped Sb{sub 4}Te film to 102 Degree-Sign C of STO3 film. Phase transition from amorphous state to crystalline state is observed at relatively lower power, compared with a device using Ge{sub 2}Sb{sub 2}Te{sub 5} film.

NF-kappaB is involved in SHetA2 circumvention of TNF-alpha resistance, but not induction of intrinsic apoptosis.

Science.gov (United States)

Chengedza, Shylet; Benbrook, Doris Mangiaracina

2010-03-01

Treatment of cancer with tumor necrosis factor-alpha (TNF-alpha) is hindered by resistance and toxicity. The flexible heteroarotinoid, SHetA2, sensitizes resistant ovarian cancer cells to TNF-alpha-induced extrinsic apoptosis, and also induces intrinsic apoptosis as a single agent. This study tested the hypothesis that nuclear factor-kappaB (NF-kappaB) is involved in SHetA2-regulated intrinsic and extrinsic apoptosis. SHetA2 inhibited basal and TNF-alpha-induced or hydrogen peroxide-induced NF-kappaB activity through counter-regulation of upstream kinase (IkappaB kinase) activity, inhibitor protein (IkappaB-alpha) phosphorylation, and p-65 NF-kappaB subunit nuclear translocation, but independently of reactive oxygen species generation. Ectopic over-expression of p-65, or treatment with TNF-alpha receptor 1 (TNFR1) small interfering RNA or a caspase-8 inhibitor, each attenuated synergistic apoptosis by SHetA2 and TNF-alpha, but did not affect intrinsic apoptosis caused by SHetA2. In conclusion, NF-kappaB repression is involved in SHetA2 circumvention of resistance to TNF-alpha-induced extrinsic apoptosis, but not in SHetA2 induction of intrinsic apoptosis.

Ferroelectric Zinc Oxide Nanowire Embedded Flexible Sensor for Motion and Temperature Sensing.

Science.gov (United States)

Shin, Sung-Ho; Park, Dae Hoon; Jung, Joo-Yun; Lee, Min Hyung; Nah, Junghyo

2017-03-22

We report a simple method to realize multifunctional flexible motion sensor using ferroelectric lithium-doped ZnO-PDMS. The ferroelectric layer enables piezoelectric dynamic sensing and provides additional motion information to more precisely discriminate different motions. The PEDOT:PSS-functionalized AgNWs, working as electrode layers for the piezoelectric sensing layer, resistively detect a change of both movement or temperature. Thus, through the optimal integration of both elements, the sensing limit, accuracy, and functionality can be further expanded. The method introduced here is a simple and effective route to realize a high-performance flexible motion sensor with integrated multifunctionalities.

Parallel screening of wild-type and drug-resistant targets for anti-resistance neuraminidase inhibitors.

Directory of Open Access Journals (Sweden)

Kai-Cheng Hsu

Full Text Available Infection with influenza virus is a major public health problem, causing serious illness and death each year. Emergence of drug-resistant influenza virus strains limits the effectiveness of drug treatment. Importantly, a dual H275Y/I223R mutation detected in the pandemic influenza A 2009 virus strain results in multidrug resistance to current neuraminidase (NA drugs. Therefore, discovery of new agents for treating multiple drug-resistant (MDR influenza virus infections is important. Here, we propose a parallel screening strategy that simultaneously screens wild-type (WT and MDR NAs, and identifies inhibitors matching the subsite characteristics of both NA-binding sites. These may maintain their potency when drug-resistant mutations arise. Initially, we analyzed the subsite of the dual H275Y/I223R NA mutant. Analysis of the site-moiety maps of NA protein structures show that the mutant subsite has a relatively small volume and is highly polar compared with the WT subsite. Moreover, the mutant subsite has a high preference for forming hydrogen-bonding interactions with polar moieties. These changes may drive multidrug resistance. Using this strategy, we identified a new inhibitor, Remazol Brilliant Blue R (RB19, an anthraquinone dye, which inhibited WT NA and MDR NA with IC(50 values of 3.4 and 4.5 µM, respectively. RB19 comprises a rigid core scaffold and a flexible chain with a large polar moiety. The former interacts with highly conserved residues, decreasing the probability of resistance. The latter forms van der Waals contacts with the WT subsite and yields hydrogen bonds with the mutant subsite by switching the orientation of its flexible side chain. Both scaffolds of RB19 are good starting points for lead optimization. The results reveal a parallel screening strategy for identifying resistance mechanisms and discovering anti-resistance neuraminidase inhibitors. We believe that this strategy may be applied to other diseases with high

Pure oxygen for the urban water waste treatment; Oxigeno puro para tratamiento de aguas residuales urbanas

Energy Technology Data Exchange (ETDEWEB)

Estevez Pastor, F.S.; Ferrer Gaztambide, J. [EDAR La China (Spain)

1995-11-01

The pilot plant for waste water treatment in La China (Spain) is described. This plant used pure oxygen for the waste water treatment. The best depuration, the flexibility to experiment the fluctuations of flow and change are studied. (Author)

Piggyback resistive Micromegas

CERN Document Server

Attié, D; Durand, D; Desforge, D; Ferrer-Ribas, E; Galán, J; Giomataris, Y; Gongadze, A; Iguaz, F J; Jeanneau, F; de Oliveira, R; Papaevangelou, T; Peyaud, A; Teixeira, A

2013-01-01

Piggyback Micromegas consists in a novel readout architecture where the anode element is made of a resistive layer on a ceramic substrate. The resistive layer is deposited on the thin ceramic substrate by an industrial process which provides large dynamic range of resistivity (10$^6$ to 10$^{10}$\\,M$\\Omega$/square). The particularity of this new structure is that the active part is entirely dissociated from the read-out element. This gives a large flexibility on the design of the anode structure and the readout scheme. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection for the electronics. This assembly could be combined with modern pixel array electronic ASICs. First tests with different Piggyback detectors and configurations will be presented. This structure is adequate for cost effective fabrication and low outgassing detectors. It was designed to perform ...

Full densification of inkjet-printed copper conductive tracks on a flexible substrate utilizing a hydrogen plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Kwon, Young-Tae [Department of Fusion Chemical Engineering, Hanyang University, Ansan 15588 (Korea, Republic of); Lee, Young-In [Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811 (Korea, Republic of); Kim, Seil [Department of Fusion Chemical Engineering, Hanyang University, Ansan 15588 (Korea, Republic of); Lee, Kun-Jae [Department of Energy Engineering, Dankook University, Cheonan 31116 (Korea, Republic of); Choa, Yong-Ho, E-mail: choa15@hanyang.ac.kr [Department of Fusion Chemical Engineering, Hanyang University, Ansan 15588 (Korea, Republic of)

2017-02-28

Highlights: • Hydrogen thermally- and plasma- treatments are applied to reduce and sinter the inkjet-printed copper patterns at low temperature. • Plasma sintered Cu patterns have fully densified microstructure with the resistivity of 3.23 μW cm. • Cu conductive track with dense microstructure remains its electrical resistivity after 1 month. • Thermal sintered Cu patterns show a relatively poor microstructure and high resistivity. - Abstract: Low temperature sintering techniques are crucial in developing flexible printed electronics. In this work, we demonstrate a novel hydrogen plasma sintering method that achieves a full reduction and densification of inkjet-printed patterns using a copper complex ion ink. After inkjet printing on polyethylene terephthalate (PET) substrates, both hydrogen plasma and conventional hydrogen thermal treatment were employed to compare the resulting microstructures, electrical properties and anti-oxidation behavior. The plasma treated pattern shows a fully densified microstructure with a resistivity of 3.23 μΩ cm, while the thermally treated pattern shows a relatively poor microstructure and high resistivity. In addition, the hydrogen plasma-treated copper pattern retains its electrical resistivity for one month without any significant decrease. This novel hydrogen plasma sintering technique could be used to produce conductive patterns with excellent electrical properties, allowing for highly reliable flexible printed electronics.

Central extracorporeal membrane oxygenation requiring pulmonary arterial venting after near-drowning.

Science.gov (United States)

Kimura, Mitsutoshi; Kinoshita, Osamu; Fujimoto, Yoshifumi; Murakami, Arata; Shindo, Takahiro; Kashiwa, Koichi; Ono, Minoru

2014-02-01

Extracorporeal membrane oxygenation (ECMO) is an effective respiratory and circulatory support in patients in refractory cardiogenic shock or cardiac arrest. Peripheral ECMO sometimes requires left heart drainage; however, few reports state that pulmonary arterial (PA) venting is required during ECMO support. We present a case of a 14-year-old boy who required PA venting during ECMO support after resuscitation from near-drowning in freshwater. A biventricular assist device with an oxygenator implantation was intended on day 1; however, we were unable to proceed because of increasing of pulmonary vascular resistance from the acute lung injury. Central ECMO with PA venting was then performed. On day 13, central ECMO was converted to biventricular assist device with an oxygenator, which was removed on day 16. This case suggests that PA venting during ECMO support may be necessary in some cases of respiratory and circulatory failure with high pulmonary vascular resistance after near-drowning.

A novel and simple method of printing flexible conductive circuits on PET fabrics

International Nuclear Information System (INIS)

Wang, Zehong; Wang, Wei; Jiang, Zhikang; Yu, Dan

2017-01-01

Highlights: • A simple preparation of nano-silver conductive ink was proposed. • Conductive pattern was printed on PET fabrics without heat sintering. • The surface resistivity of printed pattern is low to 0.197 Ω cm. - Abstract: Flexible conductive circuits on PET fabrics were fabricated by a simple approach. Firstly, well dispersed nano-silver colloids with average size of 87 nm were synthesized with poly (vinyl pyrrolidone). Then, by adding polyurethane and thickening agent into these colloids, Ag NP-based ink was produced and printed on PET fabrics by screen printing. Conductive patterns were achieved through the swelling process of polyurethane and the decrease of contact resistance between nano-silver particles when immersed in dichloromethane (DCM) and diallyldimethylammonium chloride (DMDAAC) mixed solution. After it was dried at 40 °C,the surface resistivity was about 0.197 Ω cm with width 1.9 mm, and thickness 20 μm. Moreover, the effects of different DCM contents on the conductivity and the film forming ability have been investigated. We believe these foundings will provide some important analysis for printing flexible conductive circuits on textiles.

A novel and simple method of printing flexible conductive circuits on PET fabrics

Energy Technology Data Exchange (ETDEWEB)

Wang, Zehong; Wang, Wei [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education (China); Jiang, Zhikang [Saintyear Holding Group Co., Ltd. (China); Yu, Dan, E-mail: vchtian@163.com [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education (China); Saintyear Holding Group Co., Ltd. (China)

2017-02-28

Highlights: • A simple preparation of nano-silver conductive ink was proposed. • Conductive pattern was printed on PET fabrics without heat sintering. • The surface resistivity of printed pattern is low to 0.197 Ω cm. - Abstract: Flexible conductive circuits on PET fabrics were fabricated by a simple approach. Firstly, well dispersed nano-silver colloids with average size of 87 nm were synthesized with poly (vinyl pyrrolidone). Then, by adding polyurethane and thickening agent into these colloids, Ag NP-based ink was produced and printed on PET fabrics by screen printing. Conductive patterns were achieved through the swelling process of polyurethane and the decrease of contact resistance between nano-silver particles when immersed in dichloromethane (DCM) and diallyldimethylammonium chloride (DMDAAC) mixed solution. After it was dried at 40 °C,the surface resistivity was about 0.197 Ω cm with width 1.9 mm, and thickness 20 μm. Moreover, the effects of different DCM contents on the conductivity and the film forming ability have been investigated. We believe these foundings will provide some important analysis for printing flexible conductive circuits on textiles.

Balance and flexibility.

Science.gov (United States)

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.

Engineering Pyrite-Type Bimetallic Ni-Doped CoS2 Nanoneedle Arrays over a Wide Compositional Range for Enhanced Oxygen and Hydrogen Electrocatalysis with Flexible Property

Directory of Open Access Journals (Sweden)

Guowei He

2017-11-01

Full Text Available The development of cheap and efficient catalytic electrodes is of great importance, to promote the sluggish overall water-splitting systems associated with the large-scale application of clean and renewable energy technologies. In this work, we report the controlled synthesis of pyrite-type bimetallic Ni-doped CoS2 nanoneedle (NN arrays supported on stainless steel (SS (designated as NixCo1−xS2 NN/SS, 0 ≤ x ≤ 1 and the related compositional influence on electrocatalytic efficiencies for the oxygen and hydrogen evolution reaction (OER/HER. Impressively, the Ni0.33Co0.67S2 NN/SS displays superior activity and faster kinetics for catalyzing OER (low overpotential of 286 mV at 50 mA cm−2; Tafel value of 55 mV dec−1 and HER (low overpotential of 350 mV at 30 mA cm−2; Tafel value of 76 mV dec−1 than those of counterparts with other Ni/Co ratios and also monometallic Ni- or Co-based sulfides, which is attributed to the optimized balance from the improved electron transfer capability, increased exposure of electrocatalytic active sites, and favorable dissipation of gaseous products over the nanoneedle surface. Furthermore, the conductive, flexible SS support and firmly attached in-situ integrated feature, result in the flexibility and remarkable long-term stability of as-prepared binder-free Ni0.33Co0.67S2 NN/SS electrode. These results demonstrate element-doping could be an efficient route at the atomic level to design new materials and further optimize the surface physicochemical properties for enhancing the overall electrochemical water splitting activity.

Antimicrobial photodynamic inactivation: a bright new technique to kill resistant microbes

OpenAIRE

Hamblin, Michael R

2016-01-01

Photodynamic therapy (PDT) uses photosensitizers (non-toxic dyes) that are activated by absorption of visible light to form reactive oxygen species (including singlet oxygen) that can oxidize biomolecules and destroy cells. Antimicrobial photodynamic inactivation (aPDI) can treat localized infections. aPDI neither causes any resistance to develop in microbes, nor is affected by existing drug resistance status. We discuss some recent developments in aPDI. New photosensitizers including polycat...

Transparent Indium Tin Oxide Electrodes on Muscovite Mica for High-Temperature-Processed Flexible Optoelectronic Devices.

Science.gov (United States)

Ke, Shanming; Chen, Chang; Fu, Nianqing; Zhou, Hua; Ye, Mao; Lin, Peng; Yuan, Wenxiang; Zeng, Xierong; Chen, Lang; Huang, Haitao

2016-10-26

Sn-doped In 2 O 3 (ITO) electrodes were deposited on transparent and flexible muscovite mica. The use of mica substrate makes a high-temperature annealing process (up to 500 °C) possible. ITO/mica retains its low electric resistivity even after continuous bending of 1000 times on account of the unique layered structure of mica. When used as a transparent flexible heater, ITO/mica shows an extremely fast ramping (solar cells (PSCs) with high efficiency.

Experimental investigation on photoelectric properties of ZAO thin film deposited on flexible substrate by magnetron sputtering

Science.gov (United States)

Hao, Ming; Liu, Kun; Liu, Xinghua; Wang, Dongyang; Ba, Dechun; Xie, Yuanhua; Du, Guangyu; Ba, Yaoshuai

2016-12-01

Transparent conductive ZAO (Zinc Aluminum Oxide) films on flexible substrates have a great potential for low-cost mass-production solar cells. ZAO thin films were achieved on flexible PET (polyethylene terephthalate) substrates by RF magnetron sputtering technology. The surface morphology and element content, the transmittance and the sheet resistance of the films were measured to determine the optical process parameters. The results show that the ZAO thin film shows the best parameters in terms of photoelectric performance including sputtering power, working pressure, sputtering time, substrate temperature (100 W, 1.5 Pa, 60 min, 125 °C). The sheet resistance of 510 Ω and transmittance in visible region of 92% were obtained after characterization. Surface morphology was uniform and compact with a good crystal grain.

Cysteine desulfurase IscS2 plays a role in oxygen resistance in Clostridium difficile.

Science.gov (United States)

Giordano, Nicole; Hastie, Jessica L; Smith, Ashley D; Foss, Elissa D; Gutierrez-Munoz, Daniela F; Carlson, Paul E

2018-06-04

Clostridium difficile is an anaerobic, spore-forming bacterium capable of colonizing the gastrointestinal tract of humans following disruption of the normal microbiota, typically from antibiotic therapy for an unrelated infection. With approximately 500,000 confirmed infections leading to 29,000 deaths per year in the United States, C. difficile infection (CDI) is an urgent public health threat. We previously determined C. difficile survives in up to 3% oxygen. Low levels of oxygen are present in the intestinal tract with the higher concentrations being associated with the epithelial cell surface. Additionally, antibiotic treatment, the greatest risk factor for CDI, increases intestinal oxygen concentration. Therefore, we hypothesized that the C. difficile genome encodes mechanisms for survival during oxidative stress. Previous data have shown that cysteine desulfurases involved in iron-sulfur cluster assembly are involved in protecting bacteria from oxidative stress. In this study, deletion of a putative cysteine desulfurase ( Cd 630_12790/IscS2) involved in the iron sulfur cluster (Isc) system caused a severe growth defect in the presence of 2% oxygen. Additionally, this mutant delayed colonization in a conventional mouse model of CDI, and failed to colonize in a germ-free model, which has higher intestinal oxygen levels. These data imply an undefined role for this cysteine desulfurase in protecting C. difficile from low levels of oxygen in the gut. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.

Resistance Training for Diabetes Prevention and Therapy: Experimental Findings and Molecular Mechanisms

Directory of Open Access Journals (Sweden)

Barbara Strasser

2013-01-01

Full Text Available Type 2 diabetes mellitus (T2D is characterized by insulin resistance, impaired glycogen synthesis, lipid accumulation, and impaired mitochondrial function. Exercise training has received increasing recognition as a cornerstone in the prevention and treatment of T2D. Emerging research suggests that resistance training (RT has the power to combat metabolic dysfunction in patients with T2D and seems to be an effective measure to improve overall metabolic health and reduce metabolic risk factors in diabetic patients. However, there is limited mechanistic insight into how these adaptations occur. This review provides an overview of the intervention data on the impact of RT on glucose metabolism. In addition, the molecular mechanisms that lead to adaptation in skeletal muscle in response to RT and that are associated with possible beneficial metabolic responses are discussed. Some of the beneficial adaptations exerted by RT include increased GLUT4 translocation in skeletal muscle, increased insulin sensitivity and hence restored metabolic flexibility. Increased energy expenditure and excess postexercise oxygen consumption in response to RT may be other beneficial effects. RT is increasingly establishing itself as an effective measure to improve overall metabolic health and reduce metabolic risk factors in diabetic patients.

Improved Internal Reference Oxygen Sensors with Composite Ceramic Electrodes

DEFF Research Database (Denmark)

Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

2012-01-01

Potentiometric oxygen sensors with an internal reference electrode, which uses the equilibrium pO2 of the binary mixture of Ni/NiO as the reference, are demonstrated. The cells employ Pt or composite ceramics as the sensing electrode. The cells are fabricated by a flexible and potentially low cost...... and performance are highly reproducible. The composite ceramics, based on strontium doped manganite and yttria doped zirconia, are proven superior over Pt to serve as the electrode material....

The role of Cercospora zeae-maydis homologs of Rhodobacter sphaeroides 1O2-resistance genes in resistance to the photoactivated toxin cercosporin.

Science.gov (United States)

Beseli, Aydin; Goulart da Silva, Marilia; Daub, Margaret E

2015-01-01

The photosynthetic bacterium Rhodobacter sphaeroides and plant pathogenic fungus Cercospora nicotianae have been used as models for understanding resistance to singlet oxygen ((1)O(2)), a highly toxic reactive oxygen species. In Rhodobacter and Cercospora, (1)O(2) is derived, respectively, from photosynthesis and from the (1)O(2)-generating toxin cercosporin which the fungus produces to parasitize plants. We identified common genes recovered in transcriptome studies of putative (1)O(2)-resistance genes in these two systems, suggesting common (1)O(2)-resistance mechanisms. To determine if the Cercospora homologs of R. sphaeroides (1)O(2)-resistance genes are involved in resistance to cercosporin, we expressed the genes in the cercosporin-sensitive fungus Neurospora crassa and assayed for increases in cercosporin resistance. Neurospora crassa transformants expressing genes encoding aldo/keto reductase, succinyl-CoA ligase, O-acetylhomoserine (thiol) lyase, peptide methionine sulphoxide reductase and glutathione S-transferase did not have elevated levels of cercosporin resistance. Several transformants expressing aldehyde dehydrogenase were significantly more resistant to cercosporin. Expression of the transgene and enzyme activity did not correlate with resistance, however. We conclude that although the genes tested in this study are important in (1)O(2) resistance in R. sphaeroides, their Cercospora homologs are not involved in resistance to (1)O(2) generated from cercosporin. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxygen ion transference number of doped lanthanum gallate

Science.gov (United States)

Wang, Shizhong; Wu, Lingli; Gao, Jie; He, Qiong; Liu, Meilin

The transference numbers for oxygen ion (t O) in several LaGaO 3-based materials are determined from oxygen concentration cells using the materials as the electrolyte, including La 0.8Sr 0.2Ga 0.8Mg 0.2O 3- δ (LSGM8282), La 0.8Sr 0.2Ga 0.8Mg 0.15Co 0.05O 3- δ (LSGMC5) and La 0.8Sr 0.2Ga 0.8Mg 0.115Co 0.085O 3- δ (LSGMC8.5). Analysis indicates that the accuracy in determination of oxygen ion transference number depends on the electrode polarization resistances of the concentration cell as well as the transport properties of the materials studied. For example, the ratio of open cell voltage to Nernst potential is a good approximation to the ionic transference number for LSGM8282. However, this approximation is no longer adequate for LSGMC5 and LSGMC8.5; the effect of electrode polarization resistances must be taken into consideration in estimation of the ionic transference numbers. In particular, the ionic transference number for LSGMC5 is as high as 0.99, suggesting that it is a promising electrolyte material for low-temperature solid-state electrochemical applications.

Highly Stretchable and Conductive Superhydrophobic Coating for Flexible Electronics.

Science.gov (United States)

Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Chen, Zhonghua; Zeng, Xingrong

2018-03-28

Superhydrophobic materials integrating stretchability with conductivity have huge potential in the emerging application horizons such as wearable electronic sensors, flexible power storage apparatus, and corrosion-resistant circuits. Herein, a facile spraying method is reported to fabricate a durable superhydrophobic coating with excellent stretchable and electrical performance by combing 1-octadecanethiol-modified silver nanoparticles (M-AgNPs) with polystyrene- b-poly(ethylene- co-butylene)- b-polystyrene (SEBS) on a prestretched natural rubber (NR) substrate. The embedding of M-AgNPs in elastic SEBS matrix and relaxation of prestretched NR substrate construct hierarchical rough architecture and endow the coating with dense charge-transport pathways. The fabricated coating exhibits superhydrophobicity with water contact angle larger than 160° and a high conductivity with resistance of about 10 Ω. The coating not only maintains superhydrophobicity at low/high stretch ratio for the newly generated small/large protuberances but also responds to stretching and bending with good sensitivity, broad sensing range, and stable response cycles. Moreover, the coating exhibits excellent durability to heat and strong acid/alkali and mechanical forces including droplet impact, kneading, torsion, and repetitive stretching-relaxation. The findings conceivably stand out as a new tool to fabricate multifunctional superhydrophobic materials with excellent stretchability and conductivity for flexible electronics under wet or corrosive environments.

Highly conductive and low cost Ni-PET flexible substrate for efficient dye-sensitized solar cells.

Science.gov (United States)

Su, Haijun; Zhang, Mingyang; Chang, Ya-Huei; Zhai, Peng; Hau, Nga Yu; Huang, Yu-Ting; Liu, Chang; Soh, Ai Kah; Feng, Shien-Ping

2014-04-23

The highly conductive and flexible nickel-polyethylene terephthalate (Ni-PET) substrate was prepared by a facile way including electrodeposition and hot-press transferring. The effectiveness was demonstrated in the counter electrode of dye-sensitized solar cells (DSSCs). The Ni film electrodeposition mechanism, microstructure, and DSSC performance for the Ni-PET flexible substrate were investigated. The uniform and continuous Ni film was first fabricated by electroplating metallic Ni on fluorine-doped tin oxide (FTO) and then intactly transferred onto PET via hot-pressing using Surlyn as the joint adhesive. The obtained flexible Ni-PET substrate shows low sheet resistance of 0.18Ω/□ and good chemical stability for the I(-)/I(3-) electrolyte. A high light-to-electric energy conversion efficiency of 7.89% was demonstrated in DSSCs system based on this flexible electrode substrate due to its high conductivity, which presents an improvement of 10.4% as compared with the general ITO-PEN flexible substrate. This method paves a facile and cost-effective way to manufacture various metals on a plastic nonconducive substrate beneficial for the devices toward flexible and rollable.

Sleep monitoring sensor using flexible metal strain gauge

Science.gov (United States)

Kwak, Yeon Hwa; Kim, Jinyong; Kim, Kunnyun

2018-05-01

This paper presents a sleep monitoring sensor based on a flexible metal strain gauge. As quality of life has improved, interest in sleep quality, and related products, has increased. In this study, unlike a conventional single sensor based on a piezoelectric material, a metal strain gauge-based array sensor based on polyimide and nickel chromium (NiCr) is applied to provide movement direction, respiration, and heartbeat data as well as contact-free use by the user during sleeping. Thin-film-type resistive strain gage sensors are fabricated through the conventional flexible printed circuit board (FPCB) process, which is very useful for commercialization. The measurement of movement direction and respiratory rate during sleep were evaluated, and the heart rate data were compared with concurrent electrocardiogram (ECG) data. An algorithm for analyzing sleep data was developed using MATLAB, and the error rate was 4.2% when compared with ECG for heart rate.

Growth of ZnO layers for transparent and flexible electronics

International Nuclear Information System (INIS)

Mofor, A.C.; Bakin, A.S.; Postels, B.; Suleiman, M.; Elshaer, A.; Waag, A.

2008-01-01

We have deposited and characterised ZnO on flexible and transparent plastic polymer. We employed a specially designed vapour phase growth system with elemental sources for zinc and oxygen and deposited thin ZnO films at temperatures below 400 deg. C. Basic photoluminescence characterisation confirms ZnO. Ohmic contacts were fabricated on these layers and the layers exhibit significantly high electron concentration with carrier mobility μ of up to 10.78 cm 2 V -1 s -1 . Furthermore, we show how these layers can be processed with conventional device processing techniques

Growth of ZnO layers for transparent and flexible electronics

Energy Technology Data Exchange (ETDEWEB)

Mofor, A.C.; Bakin, A.S.; Postels, B.; Suleiman, M.; Elshaer, A.; Waag, A. [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig (Germany)

2008-02-15

We have deposited and characterised ZnO on flexible and transparent plastic polymer. We employed a specially designed vapour phase growth system with elemental sources for zinc and oxygen and deposited thin ZnO films at temperatures below 400 deg. C. Basic photoluminescence characterisation confirms ZnO. Ohmic contacts were fabricated on these layers and the layers exhibit significantly high electron concentration with carrier mobility {mu} of up to 10.78 cm{sup 2} V{sup -1} s{sup -1}. Furthermore, we show how these layers can be processed with conventional device processing techniques.

Extremely stretchable and conductive water-repellent coatings for low-cost ultra-flexible electronics

Science.gov (United States)

Mates, Joseph E.; Bayer, Ilker S.; Palumbo, John M.; Carroll, Patrick J.; Megaridis, Constantine M.

2015-11-01

Rapid advances in modern electronics place ever-accelerating demands on innovation towards more robust and versatile functional components. In the flexible electronics domain, novel material solutions often involve creative uses of common materials to reduce cost, while maintaining uncompromised performance. Here we combine a commercially available paraffin wax-polyolefin thermoplastic blend (elastomer matrix binder) with bulk-produced carbon nanofibres (charge percolation network for electron transport, and for imparting nanoscale roughness) to fabricate adherent thin-film composite electrodes. The simple wet-based process produces composite films capable of sustained ultra-high strain (500%) with resilient electrical performance (resistances of the order of 101-102 Ω sq-1). The composites are also designed to be superhydrophobic for long-term corrosion protection, even maintaining extreme liquid repellency at severe strain. Comprised of inexpensive common materials applied in a single step, the present scalable approach eliminates manufacturing obstacles for commercially viable wearable electronics, flexible power storage devices and corrosion-resistant circuits.

Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

Energy Technology Data Exchange (ETDEWEB)

Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

2015-08-31

Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

International Nuclear Information System (INIS)

Lee, So Hee; Lim, Sooman; Kim, Haekyoung

2015-01-01

Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □ −1 and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □ −1 after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐ −1 ) and high transmittance (87.6%)

The role of Ar plasma treatment in generating oxygen vacancies in indium tin oxide thin films prepared by the sol-gel process

Energy Technology Data Exchange (ETDEWEB)

Hwang, Deuk-Kyu [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seoul, 03722 (Korea, Republic of); Misra, Mirnmoy; Lee, Ye-Eun [Department of BioNano Technology, Gachon University, 1342 Seong-nam dae-ro, Seong-nam si, Gyeonggi-do, 13120 (Korea, Republic of); Baek, Sung-Doo [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seoul, 03722 (Korea, Republic of); Myoung, Jae-Min, E-mail: jmmyoung@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seoul, 03722 (Korea, Republic of); Lee, Tae Il, E-mail: t2.lee77@gachon.ac.kr [Department of BioNano Technology, Gachon University, 1342 Seong-nam dae-ro, Seong-nam si, Gyeonggi-do, 13120 (Korea, Republic of)

2017-05-31

Highlights: • Indium tin oxide thin film with about 41 nm thickness was obtained by the sol-gel process. • Thin film exhibited low resistivity. • Sheet resistance of thin film decreases with Ar plasma treatment time. • Ar plasma treatment on thin film does not alter the crystal structure and optical properties of the ITO thin-film. • There is no significant change in oxygen vacancies after 20 min of plasma treatment. - Abstract: Argon (Ar) plasma treatment was carried out to reduce the sheet resistance of indium tin oxide (ITO) thin films. The Ar plasma treatment did not cause any significant changes to the crystal structure, surface morphology, or optical properties of the ITO thin films. However, an X-ray photoelectron spectroscopy study confirmed that the concentration of oxygen vacancies in the film dramatically increased with the plasma treatment time. Thus, we concluded that the decrease in the sheet resistance was caused by the increase in the oxygen vacancy concentration in the film. Furthermore, to verify how the concentration of oxygen vacancies in the film increased with the Ar plasma treatment time, cumulative and continuous plasma treatments were conducted. The oxygen vacancies were found to be created by surface heating via the outward thermal diffusion of oxygen atoms from inside the film.

Excimer laser sintering of indium tin oxide nanoparticles for fabricating thin films of variable thickness on flexible substrates

International Nuclear Information System (INIS)

Park, Taesoon; Kim, Dongsik

2015-01-01

Technology to fabricate electrically-conducting, transparent thin-film patterns on flexible substrates has possible applications in flexible electronics. In this work, a pulsed-laser sintering process applicable to indium tin oxide (ITO) thin-film fabrication on a substrate without thermal damage to the substrate was developed. A nanosecond pulsed laser was used to minimize thermal penetration into the substrate and to control the thickness of the sintered layer. ITO nanoparticles (NPs) of ~ 20 nm diameter were used to lower the process temperature by exploiting their low melting point. ITO thin film patterns were fabricated by first spin coating the NPs onto a surface, then sintering them using a KrF excimer laser. The sintered films were characterized using field emission scanning electron microscopy. The electrical resistivity and transparency of the film were measured by varying the process parameters. A single laser pulse could generate the polycrystalline structure (average grain size ~ 200 nm), reducing the electrical resistivity of the film by a factor of ~ 1000. The sintering process led to a minimum resistivity of 1.1 × 10 −4 Ω·m without losing the transparency of the film. The thickness of the sintered layer could be varied up to 150 nm by adjusting the laser fluence. Because the estimated thermal penetration depth in the ITO film was less than 200 nm, no thermal damage was observed in the substrate. This work suggests that the proposed process, combined with various particle deposition methods, can be an effective tool to form thin-film ITO patterns on flexible substrates. - Highlights: • Excimer laser sintering can fabricate ITO thin films on flexible substrates. • The laser pulse can form a polycrystalline structure without thermal damage. • The laser sintering process can reduce the electrical resistivity substantially. • The thickness of the sintered layer can be varied effectively

Excimer laser sintering of indium tin oxide nanoparticles for fabricating thin films of variable thickness on flexible substrates

Energy Technology Data Exchange (ETDEWEB)

Park, Taesoon; Kim, Dongsik, E-mail: dskim87@postech.ac.kr

2015-03-02

Technology to fabricate electrically-conducting, transparent thin-film patterns on flexible substrates has possible applications in flexible electronics. In this work, a pulsed-laser sintering process applicable to indium tin oxide (ITO) thin-film fabrication on a substrate without thermal damage to the substrate was developed. A nanosecond pulsed laser was used to minimize thermal penetration into the substrate and to control the thickness of the sintered layer. ITO nanoparticles (NPs) of ~ 20 nm diameter were used to lower the process temperature by exploiting their low melting point. ITO thin film patterns were fabricated by first spin coating the NPs onto a surface, then sintering them using a KrF excimer laser. The sintered films were characterized using field emission scanning electron microscopy. The electrical resistivity and transparency of the film were measured by varying the process parameters. A single laser pulse could generate the polycrystalline structure (average grain size ~ 200 nm), reducing the electrical resistivity of the film by a factor of ~ 1000. The sintering process led to a minimum resistivity of 1.1 × 10{sup −4} Ω·m without losing the transparency of the film. The thickness of the sintered layer could be varied up to 150 nm by adjusting the laser fluence. Because the estimated thermal penetration depth in the ITO film was less than 200 nm, no thermal damage was observed in the substrate. This work suggests that the proposed process, combined with various particle deposition methods, can be an effective tool to form thin-film ITO patterns on flexible substrates. - Highlights: • Excimer laser sintering can fabricate ITO thin films on flexible substrates. • The laser pulse can form a polycrystalline structure without thermal damage. • The laser sintering process can reduce the electrical resistivity substantially. • The thickness of the sintered layer can be varied effectively.

Innovative micro-textured hydroxyapatite and poly(l-lactic)-acid polymer composite film as a flexible, corrosion resistant, biocompatible, and bioactive coating for Mg implants.

Science.gov (United States)

Kim, Sae-Mi; Kang, Min-Ho; Kim, Hyoun-Ee; Lim, Ho-Kyung; Byun, Soo-Hwan; Lee, Jong-Ho; Lee, Sung-Mi

2017-12-01

The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(l-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLLA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLLA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLLA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLLA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

Atomic oxygen effects on boron nitride and silicon nitride: A comparison of ground based and space flight data

Science.gov (United States)

Cross, J. B.; Lan, E. H.; Smith, C. A.; Whatley, W. J.

1990-01-01

The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) were evaluated in a low Earth orbit (LEO) flight experiment and in a ground based simulation facility. In both the inflight and ground based experiments, these materials were coated on thin (approx. 250A) silver films, and the electrical resistance of the silver was measured in situ to detect any penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the inflight and ground based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the inflight or ground based experiments. The ground based results show good qualitative correlation with the LEO flight results, indicating that ground based facilities such as the one at Los Alamos National Lab can reproduce space flight data from LEO.

Resistance switching mechanism of La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} thin films

Energy Technology Data Exchange (ETDEWEB)

Luo, X.D. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Gao, R.L., E-mail: gaorongli2008@163.com [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Zhang, H.R; Sun, J.R. [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

2016-02-15

Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} and oxygen-deficient La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

Flexible IGZO Schottky diodes on paper

Science.gov (United States)

Kaczmarski, Jakub; Borysiewicz, Michał A.; Piskorski, Krzysztof; Wzorek, Marek; Kozubal, Maciej; Kamińska, Eliana

2018-01-01

With the development of novel device applications, e.g. in the field of robust and recyclable paper electronics, came an increased demand for the understanding and control of IGZO Schottky contact properties. In this work, a fabrication and characterization of flexible Ru-Si-O/IGZO Schottky barriers on paper is presented. It is found that an oxygen-rich atomic composition and microstructure of Ru-Si-O containing randomly oriented Ru inclusions with diameter of 3-5 nm embedded in an amorphous SiO2 matrix are effective in preventing interfacial reactions in the contact region, allowing to avoid pre-treatment of the semiconductor surface and fabricate reliable diodes at room temperature characterized by Schottky barrier height and ideality factor equal 0.79 eV and 2.13, respectively.

OXYGEN ISOTOPIC COMPOSITIONS OF SOLAR CORUNDUM GRAINS

International Nuclear Information System (INIS)

Makide, Kentaro; Nagashima, Kazuhide; Huss, Gary R.; Krot, Alexander N.

2009-01-01

Oxygen is one of the major rock-forming elements in the solar system and the third most abundant element of the Sun. Oxygen isotopic composition of the Sun, however, is not known due to a poor resolution of astronomical spectroscopic measurements. Several Δ 17 O values have been proposed for the composition of the Sun based on (1) the oxygen isotopic measurements of the solar wind implanted into metallic particles in lunar soil ( 2 O 3 ) is thermodynamically the first condensate from a cooling gas of solar composition. Corundum-bearing CAIs, however, are exceptionally rare, suggesting either continuous reaction of the corundum condensates with a cooling nebular gas and their replacement by hibonite (CaAl 12 O 19 ) or their destruction by melting together with less refractory condensates during formation of igneous CAIs. In contrast to the corundum-bearing CAIs, isolated micrometer-sized corundum grains are common in the acid-resistant residues from unmetamorphosed chondrites. These grains could have avoided multistage reprocessing during CAI formation and, therefore, can potentially provide constraints on the initial oxygen isotopic composition of the solar nebula, and, hence, of the Sun. Here we report oxygen isotopic compositions of ∼60 micrometer-sized corundum grains in the acid-resistant residues from unequilibrated ordinary chondrites (Semarkona (LL3.0), Bishunpur (LL3.1), Roosevelt County 075 (H3.2)) and unmetamorphosed carbonaceous chondrites (Orgueil (CI1), Murray (CM2), and Alan Hills A77307 (CO3.0)) measured with a Cameca ims-1280 ion microprobe. All corundum grains, except two, are 16 O-rich (Δ 17 O = -22.7 per mille ± 8.5 per mille, 2σ), and compositionally similar to the mineralogically pristine CAIs from the CR carbonaceous chondrites (-23.3 per mille ± 1.9 per mille, 2σ), and solar wind returned by the Genesis spacecraft (-27 per mille ± 6 per mille, 2σ). One corundum grain is highly 17 O-enriched (δ 17 O ∼ +60 per mille, δ 18 O �

Characterization of polymer silver pastes for screen printed flexible RFID antennas

Science.gov (United States)

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

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

Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries.

Directory of Open Access Journals (Sweden)

Philip Pearce

Full Text Available During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations.

Introduction of high oxygen concentrations into silicon wafers by high-temperature diffusion

International Nuclear Information System (INIS)

Casse, G.; Glaser, M.; Lemeilleur, F.; Ruzin, A.; Wegrzecki, M.

1999-01-01

The tolerance of silicon detectors to hadron irradiation can be improved by the introduction of a high concentration of oxygen into the starting material. High-resistivity Floating-Zone (FZ) silicon is required for detectors used in particle physics applications. A significantly high oxygen concentration (>10 17 atoms cm -3 ) cannot readily be achieved during the FZ silicon refinement. The diffusion of oxygen at elevated temperatures from a SiO 2 layer grown on both sides of a silicon wafer is a simple and effective technique to achieve high and uniform concentrations of oxygen throughout the bulk of a 300 μm thick silicon wafer

Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

Science.gov (United States)

Herald, Stephen D.; Frisby, Paul M.; Davis, Samuel Eddie

2009-01-01

Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to

Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

International Nuclear Information System (INIS)

Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai; Kim, Sang-Ho

2013-01-01

Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R s ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique

Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

Energy Technology Data Exchange (ETDEWEB)

Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai, E-mail: piaolh@kongju.ac.kr; Kim, Sang-Ho, E-mail: sangho1130@kongju.ac.kr

2013-08-01

Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R{sub s} ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique.

Low Reflectivity and High Flexibility of Tin-Doped Indium Oxide Nanofiber Transparent Electrodes

KAUST Repository

Wu, Hui

2011-01-12

Tin-doped indium oxide (ITO) has found widespread use in solar cells, displays, and touch screens as a transparent electrode; however, two major problems with ITO remain: high reflectivity (up to 10%) and insufficient flexibility. Together, these problems severely limit the applications of ITO films for future optoelectronic devices. In this communication, we report the fabrication of ITO nanofiber network transparent electrodes. The nanofiber networks show optical reflectivity as low as 5% and high flexibility; the nanofiber networks can be bent to a radius of 2 mm with negligible changes in the sheet resistance. © 2010 American Chemical Society.

Flexible demand in the GB domestic electricity sector in 2030

International Nuclear Information System (INIS)

Drysdale, Brian; Wu, Jianzhong; Jenkins, Nick

2015-01-01

Highlights: • Annual domestic demand by category and daily flexible load profiles are shown to 2030. • Valuable flexible demand requires loads to be identifiable, accessible, and useful. • The extent of flexible demand varies significantly on a diurnal and seasonal basis. • Barriers to accessing domestic demand include multiple low value loads and apathy. • Existing market structure a barrier to fully rewarding individual load flexibility. - Abstract: In order to meet greenhouse gas emissions targets the Great Britain (GB) future electricity supply will include a higher fraction of non-dispatchable generation, increasing opportunities for demand side management to maintain a supply/demand balance. This paper examines the extent of flexible domestic demand (FDD) in GB, its usefulness in system balancing and appropriate incentives to encourage consumers to participate. FDD, classified as electric space and water heating (ESWH), and cold and wet appliances, amounts to 59 TW h in 2012 (113 TW h total domestic demand) and is calculated to increase to 67 TW h in 2030. Summer and winter daily load profiles for flexible loads show significant seasonal and diurnal variations in the total flexible load and between load categories. Low levels of reflective consumer engagement with electricity consumption and a resistance to automation present barriers to effective access to FDD. A value of £1.97/household/year has been calculated for cold appliance loads used for frequency response in 2030, using 2013 market rates. The introduction of smart meters in GB by 2020 will allow access to FDD for system balancing. The low commercial value of individual domestic loads increases the attractiveness of non-financial incentives to fully exploit FDD. It was shown that appliance loads have different characteristics which can contribute to an efficient power system in different ways

High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

Science.gov (United States)

Raj, C. Justin; Rajesh, Murugesan; Manikandan, Ramu; Yu, Kook Hyun; Anusha, J. R.; Ahn, Jun Hwan; Kim, Dong-Won; Park, Sang Yeup; Kim, Byung Chul

2018-05-01

Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m2 g-1 with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg-1 in 1 M H2SO4 electrolyte and 197 Fg-1 as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H2SO4 electrolyte.

Office flexible cystoscopy.

Science.gov (United States)

Kavoussi, L R; Clayman, R V

1988-11-01

Since the development of the first purpose-built flexible cystoscope in 1984, flexible cystoscopy has become an accepted diagnostic and therapeutic modality. Indeed, it is estimated that more than 10 per cent of practicing urologists are already familiar with this technology. The flexible cystoscope has markedly extended the urologist's ability to examine the bladder, and it has become a valuable adjunct to the rigid cystoscope. Although the operation of this instrument is vastly different from that of its rigid counterpart, with practice, the technique can be learned. After experience is obtained with diagnostic flexible cystoscopy, the urologist will likely prefer this new instrument for bladder inspection, as it provides for a more thorough yet less morbid and less expensive examination. In the future, the development of improved and smaller instrumentation will further extend the therapeutic indications for flexible cystoscopy. Indeed, advances in laser technology are already providing the urologist with 300- to 600-micron (0.9 to 1.8F) flexible probes capable of incision (KTP laser), fulguration (Nd:YAG laser), and stone disintegration (tunable dye laser). Lastly, the skills obtained in using the flexible cystoscope are all readily applicable to the development of dexterity with the already available flexible nephroscope and the more recently developed flexible ureteroscope.

In situ measurement of the junction temperature of light emitting diodes using a flexible micro temperature sensor.

Science.gov (United States)

Lee, Chi-Yuan; Su, Ay; Liu, Yin-Chieh; Fan, Wei-Yuan; Hsieh, Wei-Jung

2009-01-01

This investigation aimed to fabricate a flexible micro resistive temperature sensor to measure the junction temperature of a light emitting diode (LED). The junction temperature is typically measured using a thermal resistance measurement approach. This approach is limited in that no standard regulates the timing of data capture. This work presents a micro temperature sensor that can measure temperature stably and continuously, and has the advantages of being lightweight and able to monitor junction temperatures in real time. Micro-electro-mechanical-systems (MEMS) technologies are employed to minimize the size of a temperature sensor that is constructed on a stainless steel foil substrate (SS-304 with 30 μm thickness). A flexible micro resistive temperature sensor can be fixed between the LED chip and the frame. The junction temperature of the LED can be measured from the linear relationship between the temperature and the resistance. The sensitivity of the micro temperature sensor is 0.059 ± 0.004 Ω/°C. The temperature of the commercial CREE(®) EZ1000 chip is 119.97 °C when it is thermally stable, as measured using the micro temperature sensor; however, it was 126.9 °C, when measured by thermal resistance measurement. The micro temperature sensor can be used to replace thermal resistance measurement and performs reliably.

In Situ Measurement of the Junction Temperature of Light Emitting Diodes Using a Flexible Micro Temperature Sensor

Directory of Open Access Journals (Sweden)

Wei-Jung Hsieh

2009-06-01

Full Text Available This investigation aimed to fabricate a flexible micro resistive temperature sensor to measure the junction temperature of a light emitting diode (LED. The junction temperature is typically measured using a thermal resistance measurement approach. This approach is limited in that no standard regulates the timing of data capture. This work presents a micro temperature sensor that can measure temperature stably and continuously, and has the advantages of being lightweight and able to monitor junction temperatures in real time. Micro-electro-mechanical-systems (MEMS technologies are employed to minimize the size of a temperature sensor that is constructed on a stainless steel foil substrate (SS-304 with 30 μm thickness. A flexible micro resistive temperature sensor can be fixed between the LED chip and the frame. The junction temperature of the LED can be measured from the linear relationship between the temperature and the resistance. The sensitivity of the micro temperature sensor is 0.059 ± 0.004 Ω/°C. The temperature of the commercial CREE® EZ1000 chip is 119.97 °C when it is thermally stable, as measured using the micro temperature sensor; however, it was 126.9 °C, when measured by thermal resistance measurement. The micro temperature sensor can be used to replace thermal resistance measurement and performs reliably.

Evaluation on electrical resistivity of silicon materials after electron ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 38; Issue 5. Evaluation on ... This research deals with the study of electron beam melting (EBM) methodology utilized in melting silicon material and subsequently discusses on the effect of oxygen level on electrical resistivity change after EBM process. The oxygen ...

Flexible all-carbon photovoltaics with improved thermal stability

Energy Technology Data Exchange (ETDEWEB)

Tang, Chun; Ishihara, Hidetaka; Sodhi, Jaskiranjeet; Chen, Yen-Chang; Siordia, Andrew; Martini, Ashlie; Tung, Vincent C., E-mail: ctung@ucmerced.edu

2015-04-15

The structurally robust nature of nanocarbon allotropes, e.g., semiconducting single-walled carbon nanotubes (SWCNTs) and C{sub 60}s, makes them tantalizing candidates for thermally stable and mechanically flexible photovoltaic applications. However, C{sub 60}s rapidly dissociate away from the basal of SWCNTs under thermal stimuli as a result of weak intermolecular forces that “lock up” the binary assemblies. Here, we explore use of graphene nanoribbons (GNRs) as geometrically tailored protecting layers to suppress the unwanted dissociation of C{sub 60}s. The underlying mechanisms are explained using a combination of molecular dynamics simulations and transition state theory, revealing the temperature dependent disassociation of C{sub 60}s from the SWCNT basal plane. Our strategy provides fundamental guidelines for integrating all-carbon based nano-p/n junctions with optimized structural and thermal stability. External quantum efficiency and output current–voltage characteristics are used to experimentally quantify the effectiveness of GNR membranes under high temperature annealing. Further, the resulting C{sub 60}:SWCNT:GNR ternary composites display excellent mechanical stability, even after iterative bending tests. - Graphical abstract: The incorporation of solvent resistant, mechanically flexible and electrically addressable 2-D soft graphene nanoribbons facilitates the assembly of photoconductive carbon nano-p/n junctions for thermally stable and flexible photovoltaic cells.

Flexible all-carbon photovoltaics with improved thermal stability

International Nuclear Information System (INIS)

Tang, Chun; Ishihara, Hidetaka; Sodhi, Jaskiranjeet; Chen, Yen-Chang; Siordia, Andrew; Martini, Ashlie; Tung, Vincent C.

2015-01-01

The structurally robust nature of nanocarbon allotropes, e.g., semiconducting single-walled carbon nanotubes (SWCNTs) and C 60 s, makes them tantalizing candidates for thermally stable and mechanically flexible photovoltaic applications. However, C 60 s rapidly dissociate away from the basal of SWCNTs under thermal stimuli as a result of weak intermolecular forces that “lock up” the binary assemblies. Here, we explore use of graphene nanoribbons (GNRs) as geometrically tailored protecting layers to suppress the unwanted dissociation of C 60 s. The underlying mechanisms are explained using a combination of molecular dynamics simulations and transition state theory, revealing the temperature dependent disassociation of C 60 s from the SWCNT basal plane. Our strategy provides fundamental guidelines for integrating all-carbon based nano-p/n junctions with optimized structural and thermal stability. External quantum efficiency and output current–voltage characteristics are used to experimentally quantify the effectiveness of GNR membranes under high temperature annealing. Further, the resulting C 60 :SWCNT:GNR ternary composites display excellent mechanical stability, even after iterative bending tests. - Graphical abstract: The incorporation of solvent resistant, mechanically flexible and electrically addressable 2-D soft graphene nanoribbons facilitates the assembly of photoconductive carbon nano-p/n junctions for thermally stable and flexible photovoltaic cells.

Defect Engineering toward Atomic Co-Nx -C in Hierarchical Graphene for Rechargeable Flexible Solid Zn-Air Batteries.

Science.gov (United States)

Tang, Cheng; Wang, Bin; Wang, Hao-Fan; Zhang, Qiang

2017-10-01

Rechargeable flexible solid Zn-air battery, with a high theoretical energy density of 1086 Wh kg -1 , is among the most attractive energy technologies for future flexible and wearable electronics; nevertheless, the practical application is greatly hindered by the sluggish oxygen reduction reaction/oxygen evolution reaction (ORR/OER) kinetics on the air electrode. Precious metal-free functionalized carbon materials are widely demonstrated as the most promising candidates, while it still lacks effective synthetic methodology to controllably synthesize carbocatalysts with targeted active sites. This work demonstrates the direct utilization of the intrinsic structural defects in nanocarbon to generate atomically dispersed Co-N x -C active sites via defect engineering. As-fabricated Co/N/O tri-doped graphene catalysts with highly active sites and hierarchical porous scaffolds exhibit superior ORR/OER bifunctional activities and impressive applications in rechargeable Zn-air batteries. Specifically, when integrated into a rechargeable and flexible solid Zn-air battery, a high open-circuit voltage of 1.44 V, a stable discharge voltage of 1.19 V, and a high energy efficiency of 63% at 1.0 mA cm -2 are achieved even under bending. The defect engineering strategy provides a new concept and effective methodology for the full utilization of nanocarbon materials with various structural features and further development of advanced energy materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aluminum phosphate microcapsule flame retardants for flexible polyurethane foams

Science.gov (United States)

Zhang, Bin; Liu, Hong; Han, Jian

2018-04-01

In this study, highly efficient flame-retardant aluminum phosphate (ALP) microcapsules were synthesized from ALP and ammonium phosphomolybdate trihydrate. The chemical structure of the ALP microcapsules was characterized by scanning electron microscopy and elemental analysis, and the thermal degradation behavior was investigated by thermogravimetric analysis (TGA). Subsequently, flexible polyurethane (PU) foams were prepared with the ALP microcapsules. Limiting oxygen index (LOI) tests, vertical burning tests, smoke density rating (SDR), and cone calorimetric tests were employed to investigate the combustion of the materials. The results showed that the flexible PU foams with 15 parts per hundred polyol by weight (pphp) ALP microcapsules passed the vertical burning test and they had an increased LOI value of 28.5%. The SDR value for PU/20 pphp ALP microcapsule composites was about 16.0% and the SDR value for the pure PU was about 29.0%. The corresponding flame-retardant mechanism was investigated by Fourier transform infrared spectroscopy, TGA, Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) tests, and energy-dispersive X-ray spectrometry.

Conducting filaments in Pt/ZrCuO{sub y}/Pt resistive switching memory cells

Energy Technology Data Exchange (ETDEWEB)

Tulu, Berhanu [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chu, Jinn P., E-mail: jpchu@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Wang, Sea-Fue [Department of Materials and Minerals Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China)

2015-11-15

Forming-free unipolar resistive switching with good retention time, low voltage (<1.9 V) and thin thickness (∼11 nm) is obtained in oxygen deficient Pt/ZrCuO{sub y}/Pt devices. Annealing at 150 °C is beneficial to improve the endurance from 286 to >6 × 10{sup 3} and the resistance ratio from ∼13 to ∼25. Nanoscale current path images observed using a conductive atomic force microscope reveal a current density of ∼3.0 × 10{sup 2} nA/μm{sup 2} in the ON state, almost four orders of magnitude higher than ∼3.3 × 10{sup −2} nA/μm{sup 2} in the OFF state. The resistive switching is thought to be dominated by the oxygen vacancies, which serves as the filamentary conduction in the film. - Highlights: • Oxygen deficient Pt/ZrCuOy/Pt device after annealing at 150 °C is studied. • Forming-free resistive switching with good retention time, low voltage is obtained. • Annealing is shown to improve the endurance from 286 to >6 × 10{sup 3}. • The resistive switching is thought to be dominated by the oxygen vacancies.

Bimodular high temperature planar oxygen gas sensor

Directory of Open Access Journals (Sweden)

Xiangcheng eSun

2014-08-01

Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

Large-Area Cross-Aligned Silver Nanowire Electrodes for Flexible, Transparent, and Force-Sensitive Mechanochromic Touch Screens.

Science.gov (United States)

Cho, Seungse; Kang, Saewon; Pandya, Ashish; Shanker, Ravi; Khan, Ziyauddin; Lee, Youngsu; Park, Jonghwa; Craig, Stephen L; Ko, Hyunhyub

2017-04-25

Silver nanowire (AgNW) networks are considered to be promising structures for use as flexible transparent electrodes for various optoelectronic devices. One important application of AgNW transparent electrodes is the flexible touch screens. However, the performances of flexible touch screens are still limited by the large surface roughness and low electrical to optical conductivity ratio of random network AgNW electrodes. In addition, although the perception of writing force on the touch screen enables a variety of different functions, the current technology still relies on the complicated capacitive force touch sensors. This paper demonstrates a simple and high-throughput bar-coating assembly technique for the fabrication of large-area (>20 × 20 cm 2 ), highly cross-aligned AgNW networks for transparent electrodes with the sheet resistance of 21.0 Ω sq -1 at 95.0% of optical transmittance, which compares favorably with that of random AgNW networks (sheet resistance of 21.0 Ω sq -1 at 90.4% of optical transmittance). As a proof of concept demonstration, we fabricate flexible, transparent, and force-sensitive touch screens using cross-aligned AgNW electrodes integrated with mechanochromic spiropyran-polydimethylsiloxane composite film. Our force-sensitive touch screens enable the precise monitoring of dynamic writings, tracing and drawing of underneath pictures, and perception of handwriting patterns with locally different writing forces. The suggested technique provides a robust and powerful platform for the controllable assembly of nanowires beyond the scale of conventional fabrication techniques, which can find diverse applications in multifunctional flexible electronic and optoelectronic devices.

The Pathway for Oxygen: Tutorial Modelling on Oxygen Transport from Air to Mitochondrion: The Pathway for Oxygen.

Science.gov (United States)

Bassingthwaighte, James B; Raymond, Gary M; Dash, Ranjan K; Beard, Daniel A; Nolan, Margaret

2016-01-01

The 'Pathway for Oxygen' is captured in a set of models describing quantitative relationships between fluxes and driving forces for the flux of oxygen from the external air source to the mitochondrial sink at cytochrome oxidase. The intervening processes involve convection, membrane permeation, diffusion of free and heme-bound O2 and enzymatic reactions. While this system's basic elements are simple: ventilation, alveolar gas exchange with blood, circulation of the blood, perfusion of an organ, uptake by tissue, and consumption by chemical reaction, integration of these pieces quickly becomes complex. This complexity led us to construct a tutorial on the ideas and principles; these first PathwayO2 models are simple but quantitative and cover: (1) a 'one-alveolus lung' with airway resistance, lung volume compliance, (2) bidirectional transport of solute gasses like O2 and CO2, (3) gas exchange between alveolar air and lung capillary blood, (4) gas solubility in blood, and circulation of blood through the capillary syncytium and back to the lung, and (5) blood-tissue gas exchange in capillaries. These open-source models are at Physiome.org and provide background for the many respiratory models there.

Flexible structured high-frequency film bulk acoustic resonator for flexible wireless electronics

International Nuclear Information System (INIS)

Zhou, Changjian; Shu, Yi; Yang, Yi; Ren, Tian-Ling; Jin, Hao; Dong, Shu-Rong; Chan, Mansun

2015-01-01

Flexible electronics have inspired many novel and very important applications in recent years and various flexible electronic devices such as diodes, transistors, circuits, sensors, and radiofrequency (RF) passive devices including antennas and inductors have been reported. However, the lack of a high-performance RF resonator is one of the key bottlenecks to implement flexible wireless electronics. In this study, for the first time, a novel ultra-flexible structured film bulk acoustic resonator (FBAR) is proposed. The flexible FBAR is fabricated on a flexible polyimide substrate using piezoelectric thin film aluminum nitride (AlN) for acoustic wave excitation. Both the shear wave and longitudinal wave can be excited under the surface interdigital electrodes configuration we proposed. In the case of the thickness extension mode, a flexible resonator with a working frequency as high as of 5.2325 GHz has been realized. The resonators stay fully functional under bending status and after repeated bending and re-flattening operations. This flexible high-frequency resonator will serve as a key building block for the future flexible wireless electronics, greatly expanding the application scope of flexible electronics. (paper)

Transparent ‘solution’ of ultrathin magnesium hydroxide nanocrystals for flexible and transparent nanocomposite films

International Nuclear Information System (INIS)

Wang, Jie-Xin; Sun, Qian; Chen, Bo; Zeng, Xiao-Fei; Zhang, Cong; Chen, Jian-Feng; Wu, Xi; Zou, Hai-Kui

2015-01-01

Transparent solutions of nanocrystals exhibit many unique properties, and are thus attractive materials for numerous applications. However, the synthesis of transparent nanocrystal solutions of magnesium hydroxide (MH) with wide applications is yet to be realized. Here, we report a facile two-step process, which includes a direct reactive precipitation in alcohol phase instead of aqueous phase combined with a successive surface modification, to prepare transparent alcohol solutions containing lamellar MH nanocrystals with an average size of 52 nm and an ultrathin thickness of 1–2 nm, which is the thinnest MH nanoplatelet reported in the literatures. Further, highly flexible and transparent nanocomposite films are fabricated with a solution mixing method by adding the transparent MH nanocrystal solutions into PVB solution. Considering the simplicity of the fabrication process, high transparency and good flexibility, this MH/polymer nanocomposite film is promising for flame-resistant applications in plastic electronics and optical devices with high transparency, such as flexible displays, optical filters, and flexible solar cells. (paper)

Flexible, elastic and tear-resistant networks prepared by photo-crosslinking poly(trimethylene carbonate) macromers

NARCIS (Netherlands)

Schuller-Ravoo, S.; Feijen, J.; Grijpma, D. W.

2012-01-01

Poly(trimethylene carbonate) (PTMC) macromers with molecular weights (M-n) between 1000 and 41,000 g mol(-1) were prepared by ring opening polymerization and subsequent functionalization with methacrylate end groups. Flexible networks were obtained by radical photo-crosslinking reactions of these

3D-FEM Analysis on Geogrid Reinforced Flexible Pavement Roads

Science.gov (United States)

Calvarano, Lidia Sarah; Palamara, Rocco; Leonardi, Giovanni; Moraci, Nicola

2017-12-01

Nowadays, the need to increase pavement service life, guarantee high performance, reduce service and maintenance costs has been turned a greater attention on the use of reinforcements. This paper presents findings of a numerical investigation on geogrid reinforced flexible pavement roads, under wheel traffic loads, using a three-dimensional Finite Element Method (FEM). The results obtained show the effectiveness of glass fibre grids as reinforcement which, with appropriate design and correct installation, by improving interface shear resistance, can be used to expand the performance of flexible pavements in different ways: by increasing the road service life providing a relevant contribution against superficial rutting or by decreasing the construction costs due to the reduction in the reinforced HMA layer thickness and thus of mineral aggregate required for its construction.

Uniformly active phase loaded selective catalytic reduction catalysts (V{sub 2}O{sub 5}/TNTs) with superior alkaline resistance performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Haiqiang; Wang, Penglu [Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental & Resources Science, Zhejiang University, 310058 Hangzhou (China); Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310027 (China); Chen, Xiongbo [South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655 (China); Wu, Zhongbiao, E-mail: zbwu@zju.edu.cn [Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental & Resources Science, Zhejiang University, 310058 Hangzhou (China); Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310027 (China)

2017-02-15

Highlights: • VOSO{sub 4} exhibited better synergistic effect with titanate nanotubes than NH{sub 4}VO{sub 3}. • Ion-exchange reaction occurs between VOSO{sub 4} and titanate nanotubes. • Ion-exchange resulting in uniformly vanadium distribution on titanate nanotubes. • VOSO{sub 4}-based catalyst exhibited impressive SCR activity and alkaline resistance. - Abstract: In this work, protonated titanate nanotubes was performed as a potential useful support and different vanadium precursors (NH{sub 4}VO{sub 3} and VOSO{sub 4}) were used to synthesize deNO{sub x} catalysts. The results showed that VOSO{sub 4} exhibited better synergistic effect with titanate nanotubes than NH{sub 4}VO{sub 3}, which was caused by the ion-exchange reaction. Then high loading content of vanadium, uniformly active phase distribution, better dispersion of vanadium, more acid sites, better V{sup 5+}/V{sup 4+} redox cycles and superior oxygen mobility were achieved. Besides, VOSO{sub 4}-based titanate nanotubes catalysts also showed enhanced alkaline resistance than particles (P25) based catalysts. It was strongly associated with its abundant acid sites, large surface area, flexible redox cycles and oxygen transfer ability. For the loading on protonated titanate nanotubes, active metal with cation groups was better precursors than anion ones. V{sub 2}O{sub 5}/TNTs catalyst was a promising substitute for the commercial vanadium catalysts and the work conducted herein provided a useful idea to design uniformly active phase loaded catalyst.

Oxygen ion transference number of doped lanthanum gallate

Energy Technology Data Exchange (ETDEWEB)

Wang, Shizhong; Wu, Lingli; Gao, Jie; He, Qiong [Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Liu, Meilin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)

2008-12-01

The transference numbers for oxygen ion (t{sub O}) in several LaGaO{sub 3}-based materials are determined from oxygen concentration cells using the materials as the electrolyte, including La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM8282), La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.15}Co{sub 0.05}O{sub 3-{delta}} (LSGMC5) and La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.115}Co{sub 0.085}O{sub 3-{delta}} (LSGMC8.5). Analysis indicates that the accuracy in determination of oxygen ion transference number depends on the electrode polarization resistances of the concentration cell as well as the transport properties of the materials studied. For example, the ratio of open cell voltage to Nernst potential is a good approximation to the ionic transference number for LSGM8282. However, this approximation is no longer adequate for LSGMC5 and LSGMC8.5; the effect of electrode polarization resistances must be taken into consideration in estimation of the ionic transference numbers. In particular, the ionic transference number for LSGMC5 is as high as 0.99, suggesting that it is a promising electrolyte material for low-temperature solid-state electrochemical applications. (author)

A safer and flexible method for the oxygen functionalization of carbon nanotubes by nitric acid vapors

International Nuclear Information System (INIS)

Santangelo, Saveria; Piperopoulos, Elpida; Fazio, Enza; Faggio, Giuliana; Ansari, Shabana; Lanza, Maurizio; Neri, Fortunato; Messina, Giacomo; Milone, Candida

2014-01-01

The functionalization by nitric acid vapors at azeotropic concentration has been recently proposed to eliminate drawbacks of the widely utilized liquid phase functionalization method. This work suggests to exploit the so-called “salt effect” to improve the vapor phase oxidation method in terms of safety and flexibility. Increasing the relative volatility of acid, the addition of Mg(NO 3 ) 2 salt to the HNO 3 + H 2 O solution allows (i) obtaining vapors with HNO 3 at the azeotropic concentration from a more diluted liquid solution (i.e. operating under safer conditions), and (ii) varying the concentration of HNO 3 in the vapor phase even above the azeotropic concentration limit (with improved process flexibility). High-resolution transmission electron microscopy, thermo-gravimetry, Raman spectroscopy and X-ray photoemission spectroscopy systematic analyses are carried out on pristine and oxidized nanotubes in order to assess their functionalization degree, surface chemistry and structural evolution. The most relevant finding of this preliminary study is that the nanotube functionalization extent increases linearly with the HNO 3 vapor concentration.

A safer and flexible method for the oxygen functionalization of carbon nanotubes by nitric acid vapors

Energy Technology Data Exchange (ETDEWEB)

Santangelo, Saveria, E-mail: saveria.santangelo@unirc.it [Dipartimento di Ingegneria Civile, dell’Energia, dell’Ambiente e dei Materiali (DICEAM), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Piperopoulos, Elpida [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Fazio, Enza [Dipartimento di Fisica e di Scienze della Terra (DFST), Università di Messina, 98166 Messina (Italy); Faggio, Giuliana [Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile (DIIES), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Ansari, Shabana [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Lanza, Maurizio [Istituto per i Processi Chimico Fisici (IPCF) del CNR, 98158 Messina (Italy); Neri, Fortunato [Dipartimento di Fisica e di Scienze della Terra (DFST), Università di Messina, 98166 Messina (Italy); Messina, Giacomo [Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile (DIIES), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Milone, Candida [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy)

2014-06-01

The functionalization by nitric acid vapors at azeotropic concentration has been recently proposed to eliminate drawbacks of the widely utilized liquid phase functionalization method. This work suggests to exploit the so-called “salt effect” to improve the vapor phase oxidation method in terms of safety and flexibility. Increasing the relative volatility of acid, the addition of Mg(NO{sub 3}){sub 2} salt to the HNO{sub 3} + H{sub 2}O solution allows (i) obtaining vapors with HNO{sub 3} at the azeotropic concentration from a more diluted liquid solution (i.e. operating under safer conditions), and (ii) varying the concentration of HNO{sub 3} in the vapor phase even above the azeotropic concentration limit (with improved process flexibility). High-resolution transmission electron microscopy, thermo-gravimetry, Raman spectroscopy and X-ray photoemission spectroscopy systematic analyses are carried out on pristine and oxidized nanotubes in order to assess their functionalization degree, surface chemistry and structural evolution. The most relevant finding of this preliminary study is that the nanotube functionalization extent increases linearly with the HNO{sub 3} vapor concentration.

Diffuse Reflectance Spectroscopy (DRS) of radiation-induced re-oxygenation in sensitive and resistant head and neck tumor xenografts

Science.gov (United States)

Dadgar, Sina; Rodríguez Troncoso, Joel; Rajaram, Narasimhan

2018-02-01

Currently, anatomical assessment of tumor volume performed several weeks after completion of treatment is the clinical standard to determine whether a cancer patient has responded to a treatment. However, functional changes within the tumor could potentially provide information regarding treatment resistance or response much earlier than anatomical changes. We have used diffuse reflectance spectroscopy to assess the short and long-term re-oxygenation kinetics of a human head and neck squamous cell carcinoma xenografts in response to radiation therapy. First, we injected UM-SCC-22B cell line into the flank of 50 mice to grow xenografts. Once the tumor volume reached 200 mm3 (designated as Day 1), the mice were distributed into radiation and control groups. Members of radiation group underwent a clinical dose of radiation of 2 Gy/day on Days 1, 4, 7, and 10 for a cumulative dose of 8 Gy. DRS spectra of these tumors were collected for 14 days during and after therapy, and the collected spectra of each tumor were converted to its optical properties using a lookup table-base inverse model. We found statistically significant differences in tumor growth rate between two groups which is in indication of the sensitivity of this cell line to radiation. We further acquired significantly different contents of hemoglobin and scattering magnitude and size in two groups. The scattering has previously been associated with necrosis. We furthermore found significantly different time-dependent changes in vascular oxygenation and tumor hemoglobin concentration in post-radiation days.

Corrosion inhibitor development for slightly sour environments with oxygen intrusion

Energy Technology Data Exchange (ETDEWEB)

Wylde, J.; Wang, H.; Li, J. [Clariant Oil Services North America, Calgary, AB (Canada)

2009-07-01

This presentation reported on a study that examined the effect of oxygen on the inhibition of carbon steel in slightly sour corrosion, and the initiation and propagation of localized attack. Oxygen can enter sour water injection systems through the vapor space in storage tanks and process system. Oxygen aggravates the corrosion attack by participating in the cathodic reaction under full or partial diffusion control. Laboratory testing results were reported in this presentation along with the development of corrosion inhibitors for such a slightly sour system. Bubble testing cells were used with continuous H{sub 2}/CO{sub 2} mixture gas sparging and occasional oxygen intrusion of 2 to 4 hours during a week long test. Linear polarization resistance (LPR) measurements and weight loss corrosion coupons were used to quantify the corrosion attack. The findings were presented in terms of the magnitude of localized attacks at different oxygen concentrations and intrusion periods, with and without the presence of corrosion inhibitors. tabs., figs.

[The effect of altered oxygen partial pressure on the resisitance to hypoxia and expression of oxygen-sensitive genes in Drosophila melanogaster].

Science.gov (United States)

Berezovs'kyĭ, V Ia; Chaka, O H; Litovka, I H; Levashov, M I; Ianko, R V

2014-01-01

As a result of resistance test to hypoxia of Drosophilas melanogaster of Oregon strain, we identified a high resistance (Group II) and low resistance (Group III) subpopulations of flies. Flies from groups II and III were incubated in a constant normobaric hypoxia (Po2=62-64 mm Hg) for 10 generations. A highly resistant group (Group IV) were exposed to a shortterm anoxia (Po,=1,5 mm Hg, 5 min) every generation. Larvae from Groups II, III, and IV demonstrated significantly elevated levels of Sir and CG 14740 expression. Larvae from Group II had a significantly higher expression of CG 14740 compared to group III. The restitution time after exposure to anoxia was significantly reduced in Group II (on 31% of the control values) Our results suggest that long-term adaptation to low oxygen partial pressure of highly resistant Drosophila significantly reduces the time of restitution and increases the expression of Sir2 and CG14740 genes.

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

Science.gov (United States)

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.

Use of computer graphics simulation for teaching of flexible sigmoidoscopy.

Science.gov (United States)

Baillie, J; Jowell, P; Evangelou, H; Bickel, W; Cotton, P

1991-05-01

The concept of simulation training in endoscopy is now well-established. The systems currently under development employ either computer graphics simulation or interactive video technology; each has its strengths and weaknesses. A flexible sigmoidoscopy training device has been designed which uses graphic routines--such as object oriented programming and double buffering--in entirely new ways. These programming techniques compensate for the limitations of currently available desk-top microcomputers. By boosting existing computer 'horsepower' with next generation coprocessors and sophisticated graphics tools such as intensity interpolation (Gouraud shading), the realism of computer simulation of flexible sigmoidoscopy is being greatly enhanced. The computer program has teaching and scoring capabilities, making it a truly interactive system. Use has been made of this ability to record, grade and store each trainee encounter in computer memory as part of a multi-center, prospective trial of simulation training being conducted currently in the USA. A new input device, a dummy endoscope, has been designed that allows application of variable resistance to the insertion tube. This greatly enhances tactile feedback, such as resistance during looping. If carefully designed trials show that computer simulation is an attractive and effective training tool, it is expected that this technology will evolve rapidly and be made widely available to trainee endoscopists.

Flexible thermoelectric generator using bulk legs and liquid metal interconnects for wearable electronics

International Nuclear Information System (INIS)

Suarez, Francisco; Parekh, Dishit P.; Ladd, Collin; Vashaee, Daryoosh; Dickey, Michael D.; Öztürk, Mehmet C.

2017-01-01

Highlights: •Flexible thermoelectric generator (TEG) with bulk legs. •Flexible thermoelectric generator with liquid metal interconnects. •Flexible TEG with potential to match the performance of rigid TEGs. •Flexible TEG for wearable electronics. -- Abstract: Interest in wearable electronics for continuous, long-term health and performance monitoring is rapidly increasing. The reduction in power levels consumed by sensors and electronic circuits accompanied by the advances in energy harvesting methods allows for the realization of self-powered monitoring systems that do not have to rely on batteries. For wearable electronics, thermoelectric generators (TEGs) offer the unique ability to continuously convert body heat into usable energy. For body harvesting, it is preferable to have TEGs that are thin, soft and flexible. Unfortunately, the performances of flexible modules reported to date have been far behind those of their rigid counterparts. This is largely due to lower efficiencies of the thermoelectric materials, electrical or thermal parasitic losses and limitations on leg dimensions posed by the synthesis techniques. In this work, we present an entirely new approach and explore the possibility of using standard bulk legs in a flexible package. Bulk thermoelectric legs cut from solid ingots are far superior to thermoelectric materials synthesized using other techniques. A key enabler of the proposed technology is the use of EGaIn liquid metal interconnects, which not only provide extremely low interconnect resistance but also stretchability with self-healing, both of which are essential for flexible TE modules. The results suggest that this novel approach can finally produce flexible TEGs that have the potential to challenge the rigid TEGs and provide a pathway for the realization of self-powered wearable electronics.

Highly conductive, transparent flexible films based on open rings of multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Ko, Wen-Yin; Su, Jun-Wei; Guo, Chian-Hua; Fu, Shu-Juan; Hsu, Chuen-Yuan; Lin, Kuan-Jiuh

2011-01-01

Open rings of multi-walled carbon nanotubes were stacked to form porous networks on a poly(ethylene terephthalate) substrate to form a flexible conducting film (MWCNT-PET) with good electrical conductivity and transparency by a combination of ultrasonic atomization and spin-coating technique. To enhance the electric flexibility, we spin-coated a cast film of poly(vinyl alcohol) onto the MWCNT-PET substrate, which then underwent a thermo-compression process. Field-emission scanning electron microscopy of the cross-sectional morphology illustrates that the film has a robust network with a thickness of ∼ 175 nm, and it remarkably exhibits a sheet resistance of approximately 370 Ω/sq with ∼ 77% transmittance at 550 nm even after 500 bending cycles. This electrical conductivity is much superior to that of other MWCNT-based transparent flexible films.

Flexibility@Work 2013: yearly report on flexible labor and employment

NARCIS (Netherlands)

Berkhout, E.; Heyma, A.; Prins, J.

2013-01-01

There is no clear evidence that the strong growth in the share of flexible labor relations between 2002 and 2007 points at a worldwide trend towards a larger share of flexible labor at the expense of traditional open-ended labor contracts. The growth in flexible labor varies too much between

Controllable synthesis and sintering of silver nanoparticles for inkjet-printed flexible electronics

International Nuclear Information System (INIS)

Zhang, Zhiliang; Zhu, Weiyue

2015-01-01

An effective and facile strategy was developed to successfully synthesize nearly uniform silver nanoparticles (AgNPs) with particle size of <10 nm, and demonstrated to achieve the sintering of AgNPs at room temperature for inkjet-printed flexible electronics. In such system, a series of different chain-length alkylamines were exploited as capped molecules to controllable synthesis of uniform AgNPs with the mean nanoparticle size in rang of 8.6 ± 0.9, 8.9 ± 1.2 and 9.2 ± 1.6 nm, and these ultra-small nanoparticles were very favorable to attain an excellent printing fluency. Based on the as-synthesized AgNPs, a sequence of flexible electrocircuits was successfully fabricated by ink-jet printing technique. After the dipped treatment, the printed AgNPs were achieved to spontaneous coalescence and aggregation at room temperature induced by preferential dissolution of capped molecules on AgNPs surfaces into methanol solution. These aggregated AgNPs demonstrated superior controllability, excellent stability and low resistivity in the range of 31.6–26.5 μΩ cm, and would have enormous potential in the application to be tailored for assembly of optoelectronics devices. - Highlights: • Silver nanoparticles with particle size of <10 nm was controllably synthesized. • The sintering of silver nanoparticles was conducted at room temperature. • The resistivity was reached as low as 26.5 μΩ cm for flexible electronics

Effect of oxygen content on deformation mode and corrosion behavior in β-type Ti-Mo alloy

Energy Technology Data Exchange (ETDEWEB)

Min, Xiaohua, E-mail: minxiaohua@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Bai, Pengfei [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Emura, Satoshi; Ji, Xin [Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Cheng, Congqian; Jiang, Beibei [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Tsuchiya, Koichi [Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2017-01-27

This study examined microstructural characteristics and mechanical properties in a β-type Ti-15Mo alloy (mass%) with different oxygen contents, and their corrosion behavior in simulated physiological media. With increasing oxygen content from 0.1–0.5%, lattice parameter of parent β-phase increased from X-ray diffraction profiles, and spots of athermal ω-phase became weak and diffuse through transmission electron microscopy observations. {332}<113> twin density decreased with an increase in oxygen content from 0.1–0.3% based on electron backscattered diffraction analyses, and it became almost zero when further increased oxygen content up to 0.5%. The solute oxygen atoms led to both a transition of {332}<113> twinning to dislocation slip and a suppression of β-phase to ω-phase transformation. Room-temperature tensile testing of this alloy with oxygen content ranging from 0.1–0.5%, revealed that yield strength ranged from 420 MPa to 1180 MPa and that uniform elongation ranged from 47–0.2%. The oxygen-added alloys kept a low elastic modulus obtained from stress-strain curves, and exhibited good corrosion resistance in Ringer's solution from open-circuit potential and potentiodynamic polarization measurements. A desirable balance between mechanical properties and corrosion resistance is obtainable in this alloy as biomaterials through utilizing oxygen to control the deformation mode.

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

Science.gov (United States)

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

2015-08-01

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

Resistive switching phenomenon and hole wind effect in YBCO thin films

Energy Technology Data Exchange (ETDEWEB)

Truchly, Martin; Plecenik, Tomas [Department of Experimental Physics, Comenius University, Bratislava (Slovakia); Zhitlukhina, Elena [Donetsk Institute for Physics and Engineering, Kyiv (Ukraine)

2016-07-01

We present an overview of our experimental and theoretical activities aimed to clarify the mechanism of resistive memory effects in YBCO thin layers. The phenomenon was studied by scanning spreading resistance microscopy (SSRM) and scanning tunneling microscopy (STM) techniques. The most striking feature uncovered (in contrast to previous experiments on planar bilayers with YBCO films) was the opposite voltage-bias polarity of the switching effect in all SSRM and a number of STM measurements. Observed hysteresis in current-voltage characteristics is interpreted as a movement of oxygen vacancies in the vicinity of the tip-YBCO contact. Since the charge distribution in YBCO samples is expected to be strongly inhomogeneous, the balance between the direct electrostatic force on activated oxygen ions and that caused by momentum exchange with the current carriers (holes) hitting them determines direction in which the oxygen vacancies are moving. We propose a minimalist model with the only fitting parameter that accounts for the resistance hysteresis phenomenon in the YBCO films studied.

11-Oxygenated C19 Steroids Are the Predominant Androgens in Polycystic Ovary Syndrome.

Science.gov (United States)

O'Reilly, Michael W; Kempegowda, Punith; Jenkinson, Carl; Taylor, Angela E; Quanson, Jonathan L; Storbeck, Karl-Heinz; Arlt, Wiebke

2017-03-01

Androgen excess is a defining feature of polycystic ovary syndrome (PCOS), but the exact origin of hyperandrogenemia remains a matter of debate. Recent studies have highlighted the importance of the 11-oxygenated C19 steroid pathway to androgen metabolism in humans. In this study, we analyzed the contribution of 11-oxygenated androgens to androgen excess in women with PCOS. One hundred fourteen women with PCOS and 49 healthy control subjects underwent measurement of serum androgens by liquid chromatography-tandem mass spectrometry. Twenty-four-hour urinary androgen excretion was analyzed by gas chromatography-mass spectrometry. Fasting plasma insulin and glucose were measured for homeostatic model assessment of insulin resistance. Baseline demographic data, including body mass index, were recorded. As expected, serum concentrations of the classic androgens testosterone (P PCOS. Mirroring this, serum 11-oxygenated androgens 11β-hydroxyandrostenedione, 11-ketoandrostenedione, 11β-hydroxytestosterone, and 11-ketotestosterone were significantly higher in PCOS than in control subjects, as was the urinary 11-oxygenated androgen metabolite 11β-hydroxyandrosterone. The proportionate contribution of 11-oxygenated to total serum androgens was significantly higher in patients with PCOS compared with control subjects [53.0% (interquartile range, 48.7 to 60.3) vs 44.0% (interquartile range, 32.9 to 54.9); P PCOS had significantly increased 11-oxygenated androgens. Serum 11β-hydroxyandrostenedione and 11-ketoandrostenedione correlated significantly with markers of insulin resistance. We show that 11-oxygenated androgens represent the majority of circulating androgens in women with PCOS, with close correlation to markers of metabolic risk.

Aquaregia and Oxygen Plasma Treatments on Fluorinated Tin Oxide for Assembly of PLEDs Devices Using OC1C10-PPV as Emissive Polymer

Directory of Open Access Journals (Sweden)

Emerson Roberto SANTOS

2009-02-01

Full Text Available In this work were carried out treatments with oxygen plasma and aquaregia on fluorinated tin oxide (FTO films varying the treatment times. After treatments, the samples were analyzed by techniques measurements: sheet resistance, thickness, Hall effect, transmittance and superficial roughness. Devices using FTO/PEDOT:PSS/OC1C10-PPV/Al were assembled. In this experiment some variations were observed by sheet resistance and thickness and Hall effect measurements indicated most elevated carriers concentration and resistivity for aquaregia than that oxygen plasma. The roughness was elevated for the first minutes with treatment by aquaregia too. In the I-V curves the aquaregia devices presented the lowest threshold voltage for 30 minutes and devices treated by oxygen plasma presented a behavior most resistivity different of typical curves for PLEDs devices.

Numerical Analysis of Small Deformation of Flexible Helical Flagellum of Swimming Bacteria

Science.gov (United States)

Takano, Yasunari; Goto, Tomonobu

Formulations are conducted to numerically analyze the effect of flexible flagellum of swimming bacteria. In the present model, a single-flagellate bacterium is assumed to consist of a rigid cell body of the prolate spheroidal shape and a flexible flagellum of the helical form. The resistive force theory is applied to estimate the force exerted on the flagellum. The torsional as well as the bending moments determine the curvature and the torsion of the deformed flagellum according to the Kirchhoff model for an elastic rod. The unit tangential vector along the deformed flagellum is calculated by applying evolution equations for space curves, and also a deformed shape of the flagellum is obtained.

Balance of oxygen throughout the conversion of a high-level waste melter feed to glass

Czech Academy of Sciences Publication Activity Database

Lee, S.M.; Hrma, P.; Kloužek, Jaroslav; Pokorný, R.; Hujová, Miroslava; Dixon, D.R.; Schweiger, M. J.; Kruger, A.A.

2017-01-01

Roč. 43, č. 16 (2017), s. 13113-13118 ISSN 0272-8842 Institutional support: RVO:67985891 Keywords : oxygen mass balance * feed-to-glass conversion * evolved gas * oxygen partial pressure * Fe redox ratio Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.986, year: 2016

Evaluation of flexible membrane liners as long-term barriers for uranium mill tailings

International Nuclear Information System (INIS)

1984-07-01

The National Uranium Tailings Program has commissioned a study to evaluate flexible membrane liners (geomembranes) as long-term barriers for Canadian uranium mill tailings. This study reviews the common liner type and addresses flexible liners (polymeric membranes and asphalt) in detail. Liner fabrication, design, installation, and performance are reviewed. Conceptual designs are presented for basins to accommodate 20 years accumulation of uranium tailings from mills in Elliot Lake and southeastern Athabasca. Nine polymeric and three asphalt liner types have been considered with respect to the physical and chemical environment in the uranium producing areas of Canada. All materials indicate good chemical resistance to uranium wastes but are subject to installation problems

Flame-Resistant Composite Materials For Structural Members

Science.gov (United States)

Spears, Richard K.

1995-01-01

Matrix-fiber composite materials developed for structural members occasionally exposed to hot, corrosive gases. Integral ceramic fabric surface layer essential for resistance to flames and chemicals. Endures high temperature, impedes flame from penetrating to interior, inhibits diffusion of oxygen to interior where it degrades matrix resin, resists attack by chemicals, helps resist erosion, and provides additional strength. In original intended application, composite members replace steel structural members of rocket-launching structures that deteriorate under combined influences of atmosphere, spilled propellants, and rocket exhaust. Composites also attractive for other applications in which corrosion- and fire-resistant structural members needed.

Recent Advancements in Liquid Metal Flexible Printed Electronics: Properties, Technologies, and Applications

Directory of Open Access Journals (Sweden)

Xuelin Wang

2016-11-01

Full Text Available This article presents an overview on typical properties, technologies, and applications of liquid metal based flexible printed electronics. The core manufacturing material—room-temperature liquid metal, currently mainly represented by gallium and its alloys with the properties of excellent resistivity, enormous bendability, low adhesion, and large surface tension, was focused on in particular. In addition, a series of recently developed printing technologies spanning from personal electronic circuit printing (direct painting or writing, mechanical system printing, mask layer based printing, high-resolution nanoimprinting, etc. to 3D room temperature liquid metal printing is comprehensively reviewed. Applications of these planar or three-dimensional printing technologies and the related liquid metal alloy inks in making flexible electronics, such as electronical components, health care sensors, and other functional devices were discussed. The significantly different adhesions of liquid metal inks on various substrates under different oxidation degrees, weakness of circuits, difficulty of fabricating high-accuracy devices, and low rate of good product—all of which are challenges faced by current liquid metal flexible printed electronics—are discussed. Prospects for liquid metal flexible printed electronics to develop ending user electronics and more extensive applications in the future are given.

Resistance controllability and variability improvement in a TaO{sub x}-based resistive memory for multilevel storage application

Energy Technology Data Exchange (ETDEWEB)

Prakash, A., E-mail: amitknp@postech.ac.kr, E-mail: amit.knp02@gmail.com, E-mail: hwanghs@postech.ac.kr; Song, J.; Hwang, H., E-mail: amitknp@postech.ac.kr, E-mail: amit.knp02@gmail.com, E-mail: hwanghs@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 790-784 (Korea, Republic of); Deleruyelle, D.; Bocquet, M. [Im2np, UMR CNRS 7334, Aix-Marseille Université, Marseille (France)

2015-06-08

In order to obtain reliable multilevel cell (MLC) characteristics, resistance controllability between the different resistance levels is required especially in resistive random access memory (RRAM), which is prone to resistance variability mainly due to its intrinsic random nature of defect generation and filament formation. In this study, we have thoroughly investigated the multilevel resistance variability in a TaO{sub x}-based nanoscale (<30 nm) RRAM operated in MLC mode. It is found that the resistance variability not only depends on the conductive filament size but also is a strong function of oxygen vacancy concentration in it. Based on the gained insights through experimental observations and simulation, it is suggested that forming thinner but denser conductive filament may greatly improve the temporal resistance variability even at low operation current despite the inherent stochastic nature of resistance switching process.

Digital grayscale printing for patterned transparent conducting Ag electrodes and their applications in flexible electronics

DEFF Research Database (Denmark)

Gupta, Ritu; Hösel, Markus; Jensen, Jacob

2014-01-01

Grayscale (halftone) laser printing is developed as a low-cost and solution processable fabrication method for ITO-free, semi-transparent and conducting Ag electrodes extendable over large area on a flexible substrate. The transmittance and sheet resistance is easily tunable by varying the graysc...

Flexible PVC flame retarded with expandable graphite

CSIR Research Space (South Africa)

Focke, WW

2014-02-01

Full Text Available this outstanding fire resistance. Thus flame-retardant (FR) and smoke-suppressant (SS) additives must be incorporated in order to meet product test specifications such as oxygen index, heat release rate, smoke evolution, or the extent of burning [1]. Levchik... plot for the composites fabricated in this work. For a material to be effectively flame retarded both the fire load and the fire growth index should assume low values. Figure 11 shows a dramatic decrease for all the EG composites relative to the neat...

All solution-processed micro-structured flexible electrodes for low-cost light-emitting pressure sensors fabrication.

Science.gov (United States)

Shimotsu, Rie; Takumi, Takahiro; Vohra, Varun

2017-07-31

Recent studies have demonstrated the advantage of developing pressure-sensitive devices with light-emitting properties for direct visualization of pressure distribution, potential application to next generation touch panels and human-machine interfaces. To ensure that this technology is available to everyone, its production cost should be kept as low as possible. Here, simple device concepts, namely, pressure sensitive flexible hybrid electrodes and OLED architecture, are used to produce low-cost resistive or light-emitting pressure sensors. Additionally, integrating solution-processed self-assembled micro-structures into the flexible hybrid electrodes composed of an elastomer and conductive materials results in enhanced device performances either in terms of pressure or spatial distribution sensitivity. For instance, based on the pressure applied, the measured values for the resistances of pressure sensors range from a few MΩ down to 500 Ω. On the other hand, unlike their evaporated equivalents, the combination of solution-processed flexible electrodes with an inverted OLED architectures display bright green emission when a pressure over 200 kPa is applied. At a bias of 3 V, their luminance can be tuned by applying a higher pressure of 500 kPa. Consequently, features such as fingernails and fingertips can be clearly distinguished from one another in these long-lasting low-cost devices.

Evaluation of stem borer resistance management strategies for Bt ...

African Journals Online (AJOL)

GREGORY

2011-06-01

Jun 1, 2011 ... cultivars were identified as cost-effective, flexible, easily adoptable and ... Key words: Refugia, cost-benefit analysis, Bt-maize, insect pest resistance management. ..... Refugia are part of stewardship plan for the Bt maize.

Enhanced resistive switching and multilevel behavior in bilayered HfAlO/HfAlO{sub x} structures for non-volatile memory applications

Energy Technology Data Exchange (ETDEWEB)

Faita, F. L., E-mail: fabriciofaita@gmail.com [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Departamento de Física, Universidade Federal de Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC (Brazil); Silva, J. P. B., E-mail: josesilva@fisica.uminho.pt [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto (Portugal); Pereira, M.; Gomes, M. J. M. [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

2015-12-14

In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlO{sub x} layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlO{sub x}(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlO{sub x} thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are ≈10{sup 2} and ≈5 × 10{sup 5}, respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.

First principle simulations on the effects of oxygen vacancy in HfO2-based RRAM

Directory of Open Access Journals (Sweden)

Yuehua Dai

2015-01-01

Full Text Available HfO2-based resistive random access memory (RRAM takes advantage of oxygen vacancy (V o defects in its principle of operation. Since the change in resistivity of the material is controlled by the level of oxygen deficiency in the material, it is significantly important to study the performance of oxygen vacancies in formation of conductive filament. Excluding effects of the applied voltage, the Vienna ab initio simulation package (VASP is used to investigate the orientation and concentration mechanism of the oxygen vacancies based on the first principle. The optimal value of crystal orientation [010] is identified by means of the calculated isosurface plots of partial charge density, formation energy, highest isosurface value, migration barrier, and energy band of oxygen vacancy in ten established orientation systems. It will effectively influence the SET voltage, forming voltage, and the ON/OFF ratio of the device. Based on the results of orientation dependence, different concentration models are established along crystal orientation [010]. The performance of proposed concentration models is evaluated and analyzed in this paper. The film is weakly conductive for the samples deposited in a mixture with less than 4.167at.% of V o contents, and the resistive switching (RS phenomenon cannot be observed in this case. The RS behavior improves with an increase in the V o contents from 4.167at.% to 6.25at.%; nonetheless, it is found difficult to switch to a stable state. However, a higher V o concentration shows a more favorable uniformity and stability for HfO2-based RRAM.

Transparent Electrode Based on Silver Nanowires and Polyimide for Film Heater and Flexible Solar Cell.

Science.gov (United States)

He, Xin; Duan, Feng; Liu, Junyan; Lan, Qiuming; Wu, Jianhao; Yang, Chengyan; Yang, Weijia; Zeng, Qingguang; Wang, Huafang

2017-11-29

Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53-80% and sheet resistances of 2.8-16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectronic devices, we utilized it in a film heater and a flexible solar cell. The film heater was able to generate a temperature of 58 °C at a driving voltage of 3.5 V within 20 s, indicating its potential application in heating devices that require low power consumption and fast response. The flexible solar cell based on the composite film with a transmittance value of 71% presented a power conversion efficiency of 3.53%. These successful applications proved that the fabricated Ag NWs-PI composite film is a good candidate for application in flexible optoelectronic devices.

Ductile electroless Ni-P coating onto flexible printed circuit board

Science.gov (United States)

Wang, Wenchang; Zhang, Weiwei; Wang, Yurong; Mitsuzak, Naotoshi; Chen, Zhidong

2016-03-01

In this study, a ductile electroless Ni-P coating on the flexible printed circuit board (FPCB) was prepared in an acidic nickel plating bath. The addition of dipropylamine (DPA) in electroless plating not only improves the ductility of the Ni-P coating, but also enhances the corrosion resistance. The further analysis reveals that the ductility improvement and enhancement of corrosion resistance for the Ni-P coating may be due to the fact that the addition of DPA significantly refines the volume of columnar nodule and reduce the porosity, thus leading to the released internal stress. In addition, it was found that the nodule within the Ni-P coating grew into a columnar structure, which may be also contribute to the improvement of ductility.

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

Science.gov (United States)

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

2014-12-10

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

Flexible organic tandem solar modules: a story of up-scaling

Science.gov (United States)

Spyropoulos, George D.; Kubis, Peter; Li, Ning; Lucera, Luca; Salvador, Michael; Baran, Derya; Machui, Florian; Ameri, Tayebeh; Voigt, Monika M.; Brabec, Christoph J.

2014-10-01

The competition in the field of solar energy between Organic Photovoltaics (OPVs) and several Inorganic Photovoltaic technologies is continuously increasing to reach the ultimate purpose of energy supply from inexpensive and easily manufactured solar cell units. Solution-processed printing techniques on flexible substrates attach a tremendous opportunity to the OPVs for the accomplishment of low-cost and large area applications. Furthermore, tandem architectures came to boost up even more OPVs by increasing the photon-harvesting properties of the device. In this work, we demonstrate the road of realizing flexible organic tandem solar modules constructed by a fully roll-to-roll compatible processing. The modules exhibit an efficiency of 5.4% with geometrical fill factors beyond 80% and minimized interconnection-resistance losses. The processing involves low temperature (<70 °C), coating methods compatible with slot die coating and high speed and precision laser patterning.

Reproducible low-voltage resistive switching in a low-initial-resistance Pr0.7Ca0.3MnO3 junction

International Nuclear Information System (INIS)

Li Songlin; Gang Jianlei; Li Jie; Chu Haifeng; Zheng Dongning

2008-01-01

Current-voltage (I-V) characteristics are investigated in a low-initial-resistance Ag/Pr 0.7 Ca 0.3 MnO 3 /Pt sandwich structure. It is found that the junction can show stable low and high resistance states in ±0.3 V voltage sweeping cycles. The set and reset voltage values are, respectively, +0.1 V and -0.2 V, which are very low as compared with those reported previously. Furthermore, the I-V curves in both resistance states exhibit rather linear behaviour, without any signature of metal/insulator interface effects. This implies that the Schottky interface mechanism might not be an indispensable factor for the colossal electroresistance effect. The origin of low switching voltages is attributed to the reduced effective distance for electric field action due to the sufficient oxygen content of the PCMO layer. The underlying physics is discussed in terms of the filament network model together with the field-induced oxygen vacancy motion model

Liquid-core nanocellulose-shell capsules with tunable oxygen permeability.

Science.gov (United States)

Svagan, A J; Bender Koch, C; Hedenqvist, M S; Nilsson, F; Glasser, G; Baluschev, S; Andersen, M L

2016-01-20

Encapsulation of oxygen sensitive components is important in several areas, including those in the food and pharmaceutical sectors, in order to improve shelf-life (oxidation resistance). Neat nanocellulose films demonstrate outstanding oxygen barrier properties, and thus nanocellulose-based capsules are interesting from the perspective of enhanced protection from oxygen. Herein, two types of nanocellulose-based capsules with liquid hexadecane cores were successfully prepared; a primary nanocellulose polyurea-urethane capsule (diameter: 1.66 μm) and a bigger aggregate capsule (diameter: 8.3 μm) containing several primary capsules in a nanocellulose matrix. To quantify oxygen permeation through the capsule walls, an oxygen-sensitive spin probe was dissolved within the liquid hexadecane core, allowing non-invasive measurements (spin-probe oximetry, electron spin resonance, ESR) of the oxygen concentration within the core. It was observed that the oxygen uptake rate was significantly reduced for both capsule types compared to a neat hexadecane solution containing the spin-probe, i.e. the slope of the non-steady state part of the ESR-curve was approximately one-third and one-ninth for the primary nanocellulose capsule and aggregated capsule, respectively, compared to that for the hexadecane sample. The transport of oxygen was modeled mathematically and by fitting to the experimental data, the oxygen diffusion coefficients of the capsule wall was determined. These values were, however, lower than expected and one plausible reason for this was that the ESR-technique underestimate the true oxygen uptake rate in the present systems at non-steady conditions, when the overall diffusion of oxygen was very slow. Copyright © 2015 Elsevier Ltd. All rights reserved.

Flexible Cu(In,Ga)Se2 thin-film solar cells for space application

International Nuclear Information System (INIS)

Otte, Karsten; Makhova, Liudmila; Braun, Alexander; Konovalov, Igor

2006-01-01

Thin film solar cells (TFSC) with Cu(In,Ga)Se 2 (CIGS) as absorber layer have been produced on rigid glass substrates for the terrestrial market. There exist, however, different investigations for manufacturing of TFSC on flexible substrates in order to achieve very thin and highly flexible (rollable) solar cells. Besides their capability to open new terrestrial market segments, they are considered as competitive candidates for future flexible thin film space power generators compared to traditional crystalline solar cells. This paper explains the advantages of flexible TFSC for usage in space, including:-low mass and storage volume, -high power/mass ratio [>100 W/kg at array level], -high radiation resistance against proton and electron radiation and, -lower production costs. These cells can be produced on flexible conductive and insulating substrate materials and have efficiency potentials of up to 15%. We report on the current development steps to adopt the TFSC technology to space requirements as well as the first European industrial approach to the roll-to-roll production of flexible CIGS-TFSC on polyimide as substrate material. Stability issues in space environment concern not only the TFSC itself, but all system components such as interconnects, cell assembly and flexible blankets. The adhesion of the back-contact to the substrate, the emissivity control in the infrared wavelength range, the electrical contacting and interconnection as well as flexible encapsulation are currently under investigation and are discussed in the paper. The production costs for TFSC for space application can be further reduced by sharing resources for the production of flexible TFSC for the terrestrial market; namely by using both, the existing terrestrial investment in production facilities as well as the synergies in R and D

Dynamic Model of a Rotating Flexible Arm-Flexible Root Mechanism Driven by a Shaft Flexible in Torsion

Directory of Open Access Journals (Sweden)

S.Z. Ismail

2006-01-01

Full Text Available This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation.

Native Alanine Substitution in the Glycine Hinge Modulates Conformational Flexibility of Heme Nitric Oxide/Oxygen (H-NOX) Sensing Proteins.

Science.gov (United States)

Hespen, Charles W; Bruegger, Joel J; Guo, Yirui; Marletta, Michael A

2018-06-15

Heme nitric oxide/oxygen sensing (H-NOX) domains are direct NO sensors that regulate a variety of biological functions in both bacteria and eukaryotes. Previous work on H-NOX proteins has shown that upon NO binding, a conformational change occurs along two glycine residues on adjacent helices (termed the glycine hinge). Despite the apparent importance of the glycine hinge, it is not fully conserved in all H-NOX domains. Several H-NOX sensors from the family Flavobacteriaceae contain a native alanine substitution in one of the hinge residues. In this work, the effect of the increased steric bulk within the Ala-Gly hinge on H-NOX function was investigated. The hinge in Kordia algicida OT-1 ( Ka H-NOX) is composed of A71 and G145. Ligand-binding properties and signaling function for this H-NOX were characterized. The variant A71G was designed to convert the hinge region of Ka H-NOX to the typical Gly-Gly motif. In activity assays with its cognate histidine kinase (HnoK), the wild type displayed increased signal specificity compared to A71G. Increasing titrations of unliganded A71G gradually inhibits HnoK autophosphorylation, while increasing titrations of unliganded wild type H-NOX does not inhibit HnoK. Crystal structures of both wild type and A71G Ka H-NOX were solved to 1.9 and 1.6 Å, respectively. Regions of H-NOX domains previously identified as involved in protein-protein interactions with HnoK display significantly higher b-factors in A71G compared to wild-type H-NOX. Both biochemical and structural data indicate that the hinge region controls overall conformational flexibility of the H-NOX, affecting NO complex formation and regulation of its HnoK.

Multi-functional magnesium alloys containing interstitial oxygen atoms.

Science.gov (United States)

Kang, H; Choi, H J; Kang, S W; Shin, S E; Choi, G S; Bae, D H

2016-03-15

A new class of magnesium alloys has been developed by dissolving large amounts of oxygen atoms into a magnesium lattice (Mg-O alloys). The oxygen atoms are supplied by decomposing titanium dioxide nanoparticles in a magnesium melt at 720 °C; the titanium is then completely separated out from the magnesium melt after solidification. The dissolved oxygen atoms are located at the octahedral sites of magnesium, which expand the magnesium lattice. These alloys possess ionic and metallic bonding characteristics, providing outstanding mechanical and functional properties. A Mg-O-Al casting alloy made in this fashion shows superior mechanical performance, chemical resistance to corrosion, and thermal conductivity. Furthermore, a similar Mg-O-Zn wrought alloy shows high elongation to failure (>50%) at room temperature, because the alloy plastically deforms with only multiple slips in the sub-micrometer grains (alloys are expected to open a new paradigm in commercial alloy design.

A new method to measure and model dynamic oxygen microdistributions in moving biofilms.

Science.gov (United States)

Wang, Jian-Hui; Chen, You-Peng; Dong, Yang; Wang, Xi-Xi; Guo, Jin-Song; Shen, Yu; Yan, Peng; Ma, Teng-Fei; Sun, Xiu-Qian; Fang, Fang; Wang, Jing

2017-10-01

Biofilms in natural environments offer a superior solution to mitigate water pollution. Artificially intensified biofilm reactors represented by rotating biological contactors (RBCs) are widely applied and studied. Understanding the oxygen transfer process in biofilms is an important aspect of these studies, and describing this process in moving biofilms (such as biofilms in RBCs) is a particular challenge. Oxygen transfer in RBCs behaves differently than in other biological reactors due to the special oxygen supply mode that results from alternate exposure of the biofilm to wastewater and air. The study of oxygen transfer in biofilms is indispensable for understanding biodegradation in RBCs. However, the mechanisms are still not well known due to a lack of effective tools to dynamically analyze oxygen diffusion, reaction, and microdistribution in biofilms. A new experimental device, the Oxygen Transfer Modeling Device (OTMD), was designed and manufactured for this purpose, and a mathematical model was developed to model oxygen transfer in biofilm produced by an RBC. This device allowed the simulation of the local environment around the biofilm during normal RBC operation, and oxygen concentrations varying with time and depth in biofilm were measured using an oxygen microelectrode. The experimental data conformed well to the model description, indicating that the OTMD and the model were stable and reliable. Moreover, the OTMD offered a flexible approach to study the impact of a single-factor on oxygen transfer in moving biofilms. In situ environment of biofilm in an RBC was simulated, and dynamic oxygen microdistributions in the biofilm were measured and well fitted to the built model description. Copyright © 2017 Elsevier Ltd. All rights reserved.

Toward enhanced hydrogen generation from water using oxygen permeating LCF membranes

KAUST Repository

Wu, Xiao-Yu; Chang, Le; Uddi, Mruthunjaya; Kirchen, Patrick; Ghoniem, Ahmed F.

2015-01-01

and flow rates on the feed and sweep sides on the water thermolysis rate and oxygen flux. A single step reaction mechanism is proposed for surface reactions, and three-resistance permeation models are derived. Results show that water thermolysis

Nanoscale Cross-Point Resistive Switching Memory Comprising p-Type SnO Bilayers

KAUST Repository

Hota, Mrinal Kanti; Hedhili, Mohamed N.; Wang, Qingxiao; Melnikov, Vasily; Mohammed, Omar F.; Alshareef, Husam N.

2015-01-01

Reproducible low-voltage bipolar resistive switching is reported in bilayer structures of p-type SnO films. Specifically, a bilayer homojunction comprising SnOx (oxygen-rich) and SnOy (oxygen-deficient) in nanoscale cross-point (300 × 300 nm2

High performance electrode for electrochemical oxygen generator cell based on solid electrolyte ion transport membrane

Energy Technology Data Exchange (ETDEWEB)

Zhou, Wei; Shao, Zongping; Ran, Ran; Chen, Zhihao; Zeng, Pingying; Gu, Hongxia; Jin, Wanqin; Xu, Nanping [College of Chemistry and Chemical Engineering, Nanjing University of Technology, No. 5 Xin Mofan Road, Nanjing 210009, JiangSu (China)

2007-06-30

A double-layer composite electrode based on Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} + Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (BSCF + SDC) and BSCF + SDC + Ag was investigated to be a promising cathode and also anode for the electrochemical oxygen generator based on samaria doped ceria electrolyte. The Ag particles in the second layer were not only the current collector but also the improver for the oxygen adsorption at the electrode. a.c. impedance results indicated that the electrode polarization resistance, as low as 0.0058 {omega} cm{sup 2} was reached at 800 C under air. In oxygen generator cell performance test, the electrode resistance dropped to half of the value at zero current density under an applied current density of 2.34 A cm{sup -2} at 700 C, and on the same conditions the oxygen generator cell was continual working for more than 900 min with a Faradic efficiency of {proportional_to}100%. (author)

Global Sourcing Flexibility

DEFF Research Database (Denmark)

Ørberg Jensen, Peter D.; Petersen, Bent

2013-01-01

the higher costs (but decreased risk for value chain disruption) embedded in a more flexible global sourcing model that allows the firm to replicate and/or relocate activities across multiple locations. We develop a model and propositions on facilitating and constraining conditions of global sourcing...... sourcing flexibility. Here we draw on prior research in the fields of organizational flexibility, international business and global sourcing as well as case examples and secondary studies. In the second part of the paper, we discuss the implications of global sourcing flexibility for firm strategy...... and operations against the backdrop of the theory-based definition of the construct. We discuss in particular the importance of global sourcing flexibility for operational performance stability, and the trade-off between specialization benefits, emerging from location and service provider specialization, versus...

[The effects of oxygen partial pressure changes on the osteometric markers of the bone tissue in rats].

Science.gov (United States)

Berezovs'kyĭ, V Ia; Zamors'ka, T M; Ianko, R V

2013-01-01

Our purpose was to investigate the oxygen partial pressure changes on the osteometric and biochemical markers of bone tissue in rats. It was shown that breathing of altered gas mixture did not change the mass, general length, sagittal diameter and density thigh-bones in 12-month Wistar male-rats. The dosed normobaric hypoxia increased the activity of alkaline phosphatase and decreased the activity of tartrate-resistant acid phosphatase. At the same time normobaric hyperoxia with 40 and 90% oxygen conversely decreased the activity of alkaline phosphatase and increased the activity of tartrate-resistant acid phosphatase.

Oxygen vacancies induced enhancement of photoconductivity of La0.5Sr0.5CoO3 - δ thin film

Science.gov (United States)

Gao, R. L.; Fu, C. L.; Cai, W.; Chen, G.; Deng, X. L.; Yang, H. W.; Sun, J. R.; Zhao, Y. G.; Shen, B. G.

2014-09-01

Effects of light and electrical current on the electrical transport properties and photovoltaic properties of oxygen-stoichiometric La0.5Sr0.5CoO3 and oxygen-deficient La0.5Sr0.5CoO3 - δ films prepared by pulsed laser deposition have been investigated. Oxygen-deficient films annealed in a vacuum show an obvious increase of resistance and lattice parameter. Besides, a direct correlation between the magnitude of the photoconductivity and oxygen vacancies in La0.5Sr0.5CoO3 - δ films has been observed. The light illumination causes a resistance drop to show the photoconductivity effect. Moreover, the photoconductivity can be remarkably enhanced by increasing the electrical current, that is, it exhibits current-enhanced photoconductivity (CEPC) effect. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Co-O-Co conduction channel due to the accumulated oxygen vacancies and hence is believed to be responsible for the increase in higher photoconductivity. These results may be important for practical applications in photoelectric devices.

The role of oxygen in the deposition of copper–calcium thin film as diffusion barrier for copper metallization

Energy Technology Data Exchange (ETDEWEB)

Yu, Zhinong, E-mail: znyu@bit.edu.cn [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Ren, Ruihuang [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Xue, Jianshe; Yao, Qi; Li, Zhengliang; Hui, Guanbao [Beijing BOE Optoelectronics Technology Co., Ltd, Beijing 100176 (China); Xue, Wei [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China)

2015-02-15

Highlights: • The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film. • The introduction of oxygen into the deposition of CuCa film is necessary to improve the adhesion of Cu film. • The CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate. - Abstract: The properties of copper (Cu) metallization based on copper–calcium (CuCa) diffusion barrier as a function of oxygen flux in the CuCa film deposition were investigated in view of adhesion, diffusion and electronic properties. The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film, however, and increases the resistance of Cu film. The introduction of oxygen into the deposition of CuCa film induces the improvement of adhesion and crystallinity of Cu film, but produces a slight increase of resistance. The increased resistance results from the partial oxidation of Cu film. The annealing process in vacuum further improves the adhesion, crystallinity and conductivity of Cu film. X-ray diffraction (XRD) and Auger electron spectroscopy (AES) show that the CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate due to the formation of Ca oxide in the interface of CuCa/substrate.

Direct localised measurement of electrical resistivity profile in rat and embryonic chick retinas using a microprobe

Directory of Open Access Journals (Sweden)

Harald van Lintel

2010-01-01

Full Text Available We report an alternative technique to perform a direct and local measurement of electrical resistivities in a layered retinal tissue. Information on resistivity changes along the depth in a retina is important for modelling retinal stimulation by retinal prostheses. Existing techniques for resistivity-depth profiling have the drawbacks of a complicated experimental setup, a less localised resistivity probing and/or lower stability for measurements. We employed a flexible microprobe to measure local resistivity with bipolar impedance spectroscopy at various depths in isolated rat and chick embryo retinas for the first time. Small electrode spacing permitted high resolution measurements and the probe flexibility contributed to stable resistivity profiling. The resistivity was directly calculated based on the resistive part of the impedance measured with the Peak Resistance Frequency (PRF methodology. The resistivity-depth profiles for both rat and chick embryo models are in accordance with previous mammalian and avian studies in literature. We demonstrate that the measured resistivity at each depth has its own PRF signature. Resistivity profiles obtained with our setup provide the basis for the construction of an electric model of the retina. This model can be used to predict variations in parameters related to retinal stimulation and especially in the design and optimisation of efficient retinal implants.

Resonant cavity enhanced light harvesting in flexible thin-film organic solar cells

KAUST Repository

Sergeant, Nicholas P.

2013-04-24

Dielectric/metal/dielectric (DMD) electrodes have the potential to significantly increase the absorption efficiency and photocurrent in flexible organic solar cells. We demonstrate that this enhancement is attributed to a broadband cavity resonance. Silver-based semitransparent DMD electrodes with sheet resistances below 10 ohm/sq. are fabricated on flexible polyethylene terephthalate (PET) substrates in a high-throughput roll-to-roll sputtering tool. We carefully study the effect of the semitransparent DMD electrode (here composed of ZnxSnyOz/Ag/InxSn yOz) on the optical device performance of a copper phthalocyanine (CuPc)/fullerene (C60) bilayer cell and illustrate that a resonant cavity enhanced light trapping effect dominates the optical behavior of the device. © 2013 Optical Society of America.

Structure and oxygen incorporation in low pressure sputtered YBCO films

International Nuclear Information System (INIS)

Chaudhary, S.; Pandya, D. K.; Kashyap, S. C.

2002-01-01

Thin films of YBa 2 Cu 3 O 7- δ (YBCO) have been successfully grown by reactive RF-magnetron sputtering technique at low pressure. The oxygen partial pressure of 0.95 mTorr, a total pressure (argon and oxygen) of 1.9 mTorr, and a substrate temperature of 775 grad C resulted in good quality films with T C (R=0) = 85.3 K and J Cmag (4.2 K) ≅ 2x10 7 A/cm 2 . The incorporation of oxygen in the as-grown films has been controlled by using different ambient - oxygen, air or argon during in-situ cooling. The superconducting behaviour of the films was studied using resistance-temperature and low field ac-susceptibility measurements and correlated with their structure. All the films exhibited metallic conduction in the normal state. The oxygen- and air- cooled films were superconducting, possessing the usual orthorhombic structure. The argon-cooled films were non-superconducting possessing the tetragonal structure, thus implying that the structure of the film during deposition is tetragonal which transforms to either of the oxygen rich orthorhombic-I or -II phases depending upon the oxygen/air ambient. The 'δ' values of 0.14, 0.32 and 0.70 and higher 'c'-parameters of 1.1785, 1.180 and 1.183 nm have been obtained for oxygen, air and argon cooled films respectively. (Authors)

Conflicting flexibility

NARCIS (Netherlands)

De Jong, P.; Schaap, A.

2011-01-01

New buildings are designed for first users. For a sustainable approach there are many advantages in designing in flexibility and adjustability in order to enable and facilitate the other sequential users. For the first investor this flexibility is translated into improved exit values due to

Plant hemoglobins: Important players at the crossroads between oxygen and nitric oxide

DEFF Research Database (Denmark)

Gupta, Kapuganti J; Hebelstrup, Kim; Mur, Luis A J

2011-01-01

Plant hemoglobins constitute a diverse group of hemeproteins and evolutionarily belong to three different classes. Class 1 hemoglobins possess an extremely high affinity to oxygen and their main function consists in scavenging of nitric oxide (NO) at very low oxygen levels. Class 2 hemoglobins have...... at high O2 concentrations. Depending on their physical properties, hemoglobins belong either to hexacoordinate non-symbiotic or pentacoordinate symbiotic groups. Plant hemoglobins are plausible targets for improving resistance to multiple stresses....

Effect of composition on the polarization and ohmic resistances of ...

Indian Academy of Sciences (India)

2017-06-09

Jun 9, 2017 ... Solid oxide fuel cell; composite cathodes; polarization resistance; ohmic resistance; ... of Oad on LSM, (iii) conversion of Oad into oxygen ion ... ions need to flow through the low temperature sintered ..... TPB's are present) suggest the formation of face-to-face con- ..... calculated using the following equation.

Controllable Organic Resistive Switching Achieved by One-Step Integration of Cone-Shaped Contact.

Science.gov (United States)

Ling, Haifeng; Yi, Mingdong; Nagai, Masaru; Xie, Linghai; Wang, Laiyuan; Hu, Bo; Huang, Wei

2017-09-01

Conductive filaments (CFs)-based resistive random access memory possesses the ability of scaling down to sub-nanoscale with high-density integration architecture, making it the most promising nanoelectronic technology for reclaiming Moore's law. Compared with the extensive study in inorganic switching medium, the scientific challenge now is to understand the growth kinetics of nanoscale CFs in organic polymers, aiming to achieve controllable switching characteristics toward flexible and reliable nonvolatile organic memory. Here, this paper systematically investigates the resistive switching (RS) behaviors based on a widely adopted vertical architecture of Al/organic/indium-tin-oxide (ITO), with poly(9-vinylcarbazole) as the case study. A nanoscale Al filament with a dynamic-gap zone (DGZ) is directly observed using in situ scanning transmission electron microscopy (STEM) , which demonstrates that the RS behaviors are related to the random formation of spliced filaments consisting of Al and oxygen vacancy dual conductive channels growing through carbazole groups. The randomicity of the filament formation can be depressed by introducing a cone-shaped contact via a one-step integration method. The conical electrode can effectively shorten the DGZ and enhance the localized electric field, thus reducing the switching voltage and improving the RS uniformity. This study provides a deeper insight of the multiple filamentary mechanisms for organic RS effect. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inter-vertebral flexibility of the ostrich neck: implications for estimating sauropod neck flexibility.

Science.gov (United States)

Cobley, Matthew J; Rayfield, Emily J; Barrett, Paul M

2013-01-01

The flexibility and posture of the neck in sauropod dinosaurs has long been contentious. Improved constraints on sauropod neck function will have major implications for what we know of their foraging strategies, ecology and overall biology. Several hypotheses have been proposed, based primarily on osteological data, suggesting different degrees of neck flexibility. This study attempts to assess the effects of reconstructed soft tissues on sauropod neck flexibility through systematic removal of muscle groups and measures of flexibility of the neck in a living analogue, the ostrich (Struthio camelus). The possible effect of cartilage on flexibility is also examined, as this was previously overlooked in osteological estimates of sauropod neck function. These comparisons show that soft tissues are likely to have limited the flexibility of the neck beyond the limits suggested by osteology alone. In addition, the inferred presence of cartilage, and varying the inter-vertebral spacing within the synovial capsule, also affect neck flexibility. One hypothesis proposed that flexibility is constrained by requiring a minimum overlap between successive zygapophyses equivalent to 50% of zygapophyseal articular surface length (ONP50). This assumption is tested by comparing the maximum flexibility of the articulated cervical column in ONP50 and the flexibility of the complete neck with all tissues intact. It is found that this model does not adequately convey the pattern of flexibility in the ostrich neck, suggesting that the ONP50 model may not be useful in determining neck function if considered in isolation from myological and other soft tissue data.

Inter-vertebral flexibility of the ostrich neck: implications for estimating sauropod neck flexibility.

Directory of Open Access Journals (Sweden)

Matthew J Cobley

Full Text Available The flexibility and posture of the neck in sauropod dinosaurs has long been contentious. Improved constraints on sauropod neck function will have major implications for what we know of their foraging strategies, ecology and overall biology. Several hypotheses have been proposed, based primarily on osteological data, suggesting different degrees of neck flexibility. This study attempts to assess the effects of reconstructed soft tissues on sauropod neck flexibility through systematic removal of muscle groups and measures of flexibility of the neck in a living analogue, the ostrich (Struthio camelus. The possible effect of cartilage on flexibility is also examined, as this was previously overlooked in osteological estimates of sauropod neck function. These comparisons show that soft tissues are likely to have limited the flexibility of the neck beyond the limits suggested by osteology alone. In addition, the inferred presence of cartilage, and varying the inter-vertebral spacing within the synovial capsule, also affect neck flexibility. One hypothesis proposed that flexibility is constrained by requiring a minimum overlap between successive zygapophyses equivalent to 50% of zygapophyseal articular surface length (ONP50. This assumption is tested by comparing the maximum flexibility of the articulated cervical column in ONP50 and the flexibility of the complete neck with all tissues intact. It is found that this model does not adequately convey the pattern of flexibility in the ostrich neck, suggesting that the ONP50 model may not be useful in determining neck function if considered in isolation from myological and other soft tissue data.

High performance flexible pH sensor based on carboxyl-functionalized and DEP aligned SWNTs

International Nuclear Information System (INIS)

Liu, Lu; Shao, Jinyou; Li, Xiangming; Zhao, Qiang; Nie, Bangbang; Xu, Chuan; Ding, Haitao

2016-01-01

Highlights: • The flexible chemiresistive pH sensor based on two-terminal microsensors eliminating the need for a reference electrode, is simple in structure and can be fabricated on a variety of substrates such as PET, PI and PVC. • SWNTs as an ideal one dimensional material are carboxyl-functionalized to make the pH sensor show high sensitivity and outstanding flexibility for practical applications. • DEP technique is used to manipulate and position SWNTs into appropriate locations and desired formations to improve the metal-nanotube interface and highly rapid detection of pH value, resulting in better overall device performance. • Mechanical bendability of the pH sensor, which arises from the combination of flexible PET substrates and SWNTs, offer a significant improvement for applications that are difficult or impossible to achieve with traditional sensors on rigid substrates. - Abstract: The detection and control of the pH is very important in many biomedical and chemical reaction processes. A miniaturized flexible pH sensor that is light weight, robust, and conformable is very important in many applications, such as multifunctional lab-on-a-chip systems or wearable biomedical devices. In this work, we demonstrate a flexible chemiresistive pH sensor based on dielectrophoresis (DEP) aligned carboxyl-functionalized single-walled carbon nanotubes (SWNTs). Decorated carboxyl groups can react with hydrogen (H"+) and hydroxide (OH"−) ions, enabling the sensor to be capable of sensing the pH. DEP is used to deposit well-organized and highly aligned SWNTs in desired locations, which improves the metal-nanotube interface and highly rapid detection of the pH, resulting in better overall device performance. When pH buffer solutions are dropped onto such SWNTs, the H"+ and OH"− ions caninteract with the carboxyl groups and affect the generation of holes and electrons in the SWNTs, leading to resistance variations in the SWNTs. The results shows that the

High performance flexible pH sensor based on carboxyl-functionalized and DEP aligned SWNTs

Energy Technology Data Exchange (ETDEWEB)

Liu, Lu; Shao, Jinyou, E-mail: jyshao@mail.xjtu.edu.cn; Li, Xiangming; Zhao, Qiang; Nie, Bangbang; Xu, Chuan; Ding, Haitao

2016-11-15

Highlights: • The flexible chemiresistive pH sensor based on two-terminal microsensors eliminating the need for a reference electrode, is simple in structure and can be fabricated on a variety of substrates such as PET, PI and PVC. • SWNTs as an ideal one dimensional material are carboxyl-functionalized to make the pH sensor show high sensitivity and outstanding flexibility for practical applications. • DEP technique is used to manipulate and position SWNTs into appropriate locations and desired formations to improve the metal-nanotube interface and highly rapid detection of pH value, resulting in better overall device performance. • Mechanical bendability of the pH sensor, which arises from the combination of flexible PET substrates and SWNTs, offer a significant improvement for applications that are difficult or impossible to achieve with traditional sensors on rigid substrates. - Abstract: The detection and control of the pH is very important in many biomedical and chemical reaction processes. A miniaturized flexible pH sensor that is light weight, robust, and conformable is very important in many applications, such as multifunctional lab-on-a-chip systems or wearable biomedical devices. In this work, we demonstrate a flexible chemiresistive pH sensor based on dielectrophoresis (DEP) aligned carboxyl-functionalized single-walled carbon nanotubes (SWNTs). Decorated carboxyl groups can react with hydrogen (H{sup +}) and hydroxide (OH{sup −}) ions, enabling the sensor to be capable of sensing the pH. DEP is used to deposit well-organized and highly aligned SWNTs in desired locations, which improves the metal-nanotube interface and highly rapid detection of the pH, resulting in better overall device performance. When pH buffer solutions are dropped onto such SWNTs, the H{sup +} and OH{sup −} ions caninteract with the carboxyl groups and affect the generation of holes and electrons in the SWNTs, leading to resistance variations in the SWNTs. The results

Forming-Free One-Selector/One-Resistor Characteristics of Oxygen-Rich ITO Based Transparent Resistive Switching Memory via Defect Engineering Using the Reactive Sputtering Process.

Science.gov (United States)

Yun, Min Ju; Kim, Kyeong Heon; Kim, Sungho; Kim, Hee-Dong

2018-09-01

In recent research of resistive random access memory (RRAM), solving the degradation phenomenon induced by both a high forming voltage to form the conducting filaments (CFs) and a high reset current is one of the main issues encountered. In this study, to overcome these problems, we propose forming-free bipolar resistive switching (BRS) behaviors by employing an ITO film with abundant oxygen vacancies, instead of conventional CF based RRAM requiring a forming process, and systematically investigate the feasibility of forming free BRS behaviors and a possible switching mechanism. Compared to conventional CF based RRAM devices, it is possible for the proposed devices to achieve stable BRS properties (i.e., narrow variations of operating current and voltage, and retention) without the forming process, under an operating current of sub-nano ampere. In addition, the proposed cell shows a stable hysteresis of current-voltage curves, which is well matched with the Poole-Frenkel emission, and currents at a low voltage are limited due to a formed barrier height like Schottky diode between the active layer and electrodes.

SR-Site: Oxygen ingress in the rock at Forsmark during a glacial cycle

Energy Technology Data Exchange (ETDEWEB)

Sidborn, Magnus (Kemakta Konsult AB (Sweden)); Sandstroem, Bjoern (WSP Sverige AB (Sweden)); Tullborg, Eva-Lena (Terralogica AB (Sweden)); Salas, Joaquin; Maia, Flavia; Delos, Anne; Molinero, Jorge (Amphos21 (Spain)); Hallbeck, Lotta; Pedersen, Karsten (Microbial Analytics Sweden AB (Sweden))

2010-11-15

matrix is the main source of reducing capacity. The ferrous iron occurs in different reduced minerals, of which biotite and chlorite are the most abundant. The release rate of ferrous iron from biotite is slower than for most of the ferrous minerals considered. Therefore, the ferrous iron is cautiously assumed to be comprised in biotite, as a model substance, and the release rate is calculated based on this assumption. Furthermore, the oxidation of ferrous iron by oxygen is assumed to occur in two consecutive steps; dissolution of ferrous iron from the mineral lattice into the pore solution followed by homogeneous oxidation of the dissolved ferrous ions. Direct oxidation of ferrous iron incorporated in the mineral lattice is hence also cautiously approximated by these two coupled processes. At early times, reduced minerals in the undisturbed rock matrix, which are directly exposed to the flowing water, are easily accessible from the flow paths in the fractures. In this situation, the extent of oxygen ingress along the flow path is determined by the relative rates of oxygen recharge and oxygen consuming reactions. Eventually, the reducing capacity of the rock close to the fracture becomes depleted and the remaining ferrous minerals can only be reached by diffusion in the rock matrix. With time, this diffusion resistance increases as the reducing capacity is depleted further into the rock matrix. The oxygen consuming reaction is then limited by the diffusion resistance. The extent of oxygen ingress is in this situation determined by the relative rates of oxygen recharge and diffusion into the rock matrix. Both of these situations are represented by two different models that are solved analytically in this report. The case of kinetically controlled oxygen consumption for early times is furthermore evaluated with the geochemical numerical codes PHREEQC and PHAST. Sensitivity analyses of important parameters such as the pH, availability of specific reactive mineral surfaces

SR-Site: Oxygen ingress in the rock at Forsmark during a glacial cycle

International Nuclear Information System (INIS)

Sidborn, Magnus; Sandstroem, Bjoern; Tullborg, Eva-Lena; Salas, Joaquin; Maia, Flavia; Delos, Anne; Molinero, Jorge; Hallbeck, Lotta; Pedersen, Karsten

2010-11-01

matrix is the main source of reducing capacity. The ferrous iron occurs in different reduced minerals, of which biotite and chlorite are the most abundant. The release rate of ferrous iron from biotite is slower than for most of the ferrous minerals considered. Therefore, the ferrous iron is cautiously assumed to be comprised in biotite, as a model substance, and the release rate is calculated based on this assumption. Furthermore, the oxidation of ferrous iron by oxygen is assumed to occur in two consecutive steps; dissolution of ferrous iron from the mineral lattice into the pore solution followed by homogeneous oxidation of the dissolved ferrous ions. Direct oxidation of ferrous iron incorporated in the mineral lattice is hence also cautiously approximated by these two coupled processes. At early times, reduced minerals in the undisturbed rock matrix, which are directly exposed to the flowing water, are easily accessible from the flow paths in the fractures. In this situation, the extent of oxygen ingress along the flow path is determined by the relative rates of oxygen recharge and oxygen consuming reactions. Eventually, the reducing capacity of the rock close to the fracture becomes depleted and the remaining ferrous minerals can only be reached by diffusion in the rock matrix. With time, this diffusion resistance increases as the reducing capacity is depleted further into the rock matrix. The oxygen consuming reaction is then limited by the diffusion resistance. The extent of oxygen ingress is in this situation determined by the relative rates of oxygen recharge and diffusion into the rock matrix. Both of these situations are represented by two different models that are solved analytically in this report. The case of kinetically controlled oxygen consumption for early times is furthermore evaluated with the geochemical numerical codes PHREEQC and PHAST. Sensitivity analyses of important parameters such as the pH, availability of specific reactive mineral surfaces

Reinforced carbon nanotubes as electrically conducting and flexible films for space applications.

Science.gov (United States)

Atar, Nurit; Grossman, Eitan; Gouzman, Irina; Bolker, Asaf; Hanein, Yael

2014-11-26

Chemical vapor deposition (CVD)-grown entangled carbon nanotube (CNT) sheets are characterized by high electrical conductivity and durability to bending and folding. However, since freestanding CNT sheets are mechanically weak, they cannot be used as stand-alone flexible films. In this work, polyimide (PI) infiltration into entangled cup-stacked CNT (CSCNT) sheets was studied to form electrically conducting, robust, and flexible films for space applications. The infiltration process preserved CNTs' advantageous properties (i.e., conductivity and flexibility), prevented CNT agglomeration, and enabled CNT patterning. In particular, the CNT-PI films exhibited ohmic electrical conductance in both the lateral and vertical directions, with a sheet resistivity as low as 122 Ω/□, similar to that of as-grown CNT sheets, with minimal effect of the insulating matrix. Moreover, this high conductivity was preserved under mechanical and thermal manipulations. These properties make the reported CNT-PI films excellent candidates for applications where flexibility, thermal stability, and electrical conductivity are required. Particularly, the developed CNT-PI films were found to be durable in space environment hazards such as high vacuum, thermal cycling, and ionizing radiation, and hence they are suggested as an alternative for the electrostatic discharge (ESD) protection layer in spacecraft thermal blankets.

Band gap effects of hexagonal boron nitride using oxygen plasma

International Nuclear Information System (INIS)

Sevak Singh, Ram; Leong Chow, Wai; Yingjie Tay, Roland; Hon Tsang, Siu; Mallick, Govind; Tong Teo, Edwin Hang

2014-01-01

Tuning of band gap of hexagonal boron nitride (h-BN) has been a challenging problem due to its inherent chemical stability and inertness. In this work, we report the changes in band gaps in a few layers of chemical vapor deposition processed as-grown h-BN using a simple oxygen plasma treatment. Optical absorption spectra show a trend of band gap narrowing monotonically from 6 eV of pristine h-BN to 4.31 eV when exposed to oxygen plasma for 12 s. The narrowing of band gap causes the reduction in electrical resistance by ∼100 fold. The x-ray photoelectron spectroscopy results of plasma treated hexagonal boron nitride surface show the predominant doping of oxygen for the nitrogen vacancy. Energy sub-band formations inside the band gap of h-BN, due to the incorporation of oxygen dopants, cause a red shift in absorption edge corresponding to the band gap narrowing

Band gap effects of hexagonal boron nitride using oxygen plasma

Energy Technology Data Exchange (ETDEWEB)

Sevak Singh, Ram; Leong Chow, Wai [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Yingjie Tay, Roland [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Temasek Laboratories-NTU, 50 Nanyang Avenue, Singapore 639798 (Singapore); Hon Tsang, Siu [Temasek Laboratories-NTU, 50 Nanyang Avenue, Singapore 639798 (Singapore); Mallick, Govind [Temasek Laboratories-NTU, 50 Nanyang Avenue, Singapore 639798 (Singapore); Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States); Tong Teo, Edwin Hang, E-mail: htteo@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

2014-04-21

Tuning of band gap of hexagonal boron nitride (h-BN) has been a challenging problem due to its inherent chemical stability and inertness. In this work, we report the changes in band gaps in a few layers of chemical vapor deposition processed as-grown h-BN using a simple oxygen plasma treatment. Optical absorption spectra show a trend of band gap narrowing monotonically from 6 eV of pristine h-BN to 4.31 eV when exposed to oxygen plasma for 12 s. The narrowing of band gap causes the reduction in electrical resistance by ∼100 fold. The x-ray photoelectron spectroscopy results of plasma treated hexagonal boron nitride surface show the predominant doping of oxygen for the nitrogen vacancy. Energy sub-band formations inside the band gap of h-BN, due to the incorporation of oxygen dopants, cause a red shift in absorption edge corresponding to the band gap narrowing.

Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

Science.gov (United States)

Paraz, Florine; Schouveiler, Lionel; Eloy, Christophe

2016-01-01

Flexibility of marine animal fins has been thought to enhance swimming performance. However, despite numerous experimental and numerical studies on flapping flexible foils, there is still no clear understanding of the effect of flexibility and flapping amplitude on thrust generation and swimming efficiency. Here, to address this question, we combine experiments on a model system and a weakly nonlinear analysis. Experiments consist in immersing a flexible rectangular plate in a uniform flow and forcing this plate into a heaving motion at its leading edge. A complementary theoretical model is developed assuming a two-dimensional inviscid problem. In this model, nonlinear effects are taken into account by considering a transverse resistive drag. Under these hypotheses, a modal decomposition of the system motion allows us to predict the plate response amplitude and the generated thrust, as a function of the forcing amplitude and frequency. We show that this model can correctly predict the experimental data on plate kinematic response and thrust generation, as well as other data found in the literature. We also discuss the question of efficiency in the context of bio-inspired propulsion. Using the proposed model, we show that the optimal propeller for a given thrust and a given swimming speed is achieved when the actuating frequency is tuned to a resonance of the system, and when the optimal forcing amplitude scales as the square root of the required thrust.

Photodynamic therapy of cancer — Challenges of multidrug resistance

Directory of Open Access Journals (Sweden)

Zheng Huang

2015-01-01

Full Text Available Photodynamic therapy (PDT of cancer is a two-step drug-device combination modality, which involves the topical or systemic administration of a photosensitizer followed by light illumination of cancer site. In the presence of oxygen molecules, the light illumination of photosensitizer (PS can lead to the generation of cytotoxic reactive oxygen species (ROS and consequently destroy cancer. Similar to many other anticancer therapies, PDT is also subject to intrinsic cancer resistance mediated by multidrug resistance (MDR mechanisms. This paper will review the recent progress in understanding the interaction between MDR transporters and PS uptake. The strategies that can be used in a clinical setting to overcome or bypass MDR will also be discussed.

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

Energy Technology Data Exchange (ETDEWEB)

Ghoneim, M. T.; Hussain, M. M., E-mail: muhammadmustafa.hussain@kaust.edu.sa [Integrated Nanotechnology Lab, Electrical Engineering, Computer Electrical Mathematical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

2015-08-03

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

KAUST Repository

Ghoneim, Mohamed T.

2015-08-05

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