In situ X-ray studies of film cathodes for solid oxide fuel cells

International Nuclear Information System (INIS)

Fuoss, Paul; Chang, Kee-Chul; You, Hoydoo

2013-01-01

Highlights: •Synchrotron X-rays are used to study in operando the structural and chemical changes of LSM and LSCF film cathodes during half-cell operations. •A-site and B-site cations actively segregate or desegregate on the changes of temperature, pO 2 , and electrochemical potential. •Chemical lattice expansions show that oxygen-cathode interface is the primary source of rate-limiting processes. •The surface and subsurface of the LSM and LSCF films have different oxidation-states due to vacancy concentration changes. •Liquid-phase infiltration and coarsening processes of cathode materials into porous YSZ electrolyte backbone were monitored by USAXS. -- Abstract: Synchrotron-based X-ray techniques have been used to study in situ the structural and chemical changes of film cathodes during half-cell operations. The X-ray techniques used include X-ray reflectivity (XR), total-reflection X-ray fluorescence (TXRF), high-resolution diffraction (HRD), ultra-small angle X-ray scattering (USAXS). The epitaxial thin film model cathodes for XR, TXRF, and HRD measurements are made by pulse laser deposition and porous film cathodes for USAX measurements are made by screen printing technique. The experimental results reviewed here include A-site and B-site segregations, lattice expansion, oxidation-state changes during cell operations and liquid-phase infiltration and coarsening of cathode to electrolyte backbone

Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

Energy Technology Data Exchange (ETDEWEB)

Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian; Purwanto, Agus [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

2016-02-08

A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

Constitution of novel polyamic acid/polypyrrole composite films by in-situ electropolymerization

International Nuclear Information System (INIS)

Hess, Euodia H.; Waryo, Tesfaye; Sadik, Omowunmi A.; Iwuoha, Emmanuel I.; Baker, Priscilla G.L.

2014-01-01

The preparation and characterization of polyamic acid-polypyrrole (PAA/PPy) composite films are reported in this paper. The thin films were synthesized by electrochemical method from a solution containing controlled molar ratio of chemically synthesized polyamic acid (PAA) and pyrrole monomer. Homogenous films were obtained by incorporating PAA into electropolymerized polypyrrole (PPy) thin film. The concentration of PAA (1.37 × 10 −6 M) was kept fixed throughout the composite ratio analysis, whilst the concentration of PPy was varied from 1.90 × 10 −3 M to 9.90 × 10 −3 M. The PAA/PPy thin films were electrodeposited at a glassy carbon electrode (GCE) and characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and voltammetry. The composition that best represented the homogenous incorporation of PAA into PPy matrix was observed at a PAA/PPy ratio of 1: 4.13 × 10 −3 . This composite was observed to have two sets of coupled peaks with formal potential 99 mV and 567 mV respectively. The D e determined from cyclic voltammetry using the anodic peak currents were found to be twice as high (5.82 × 10 −4 cm 2 /s) compared to the D e calculated using the cathodic peak currents (2.60 × 10 −4 cm 2 /s), indicating that the composite favours anodic electron mobility. Surface morphology and spectroscopy data support the formation of a homogenous polymer blend at the synthesis ratio of 1: 4.13 × 10 −3

Influence of disordered morphology on electrochromic stability of WO{sub 3}/PPy

Energy Technology Data Exchange (ETDEWEB)

Gaikwad, Digambar K. [D. Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India); Mali, Sawanta S.; Hong, Chang K. [Polymer Energy Materials Laboratory, Department of Advanced Chemical Engineering, Chonnam National University, Gwangju, 500-757 (Korea, Republic of); Kadam, Anamika V., E-mail: anamikasonavane@rediff.com [D. Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India); D.Y. Patil Medical University, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India)

2016-06-05

Tungsten oxide (WO{sub 3}) films are critical for smart windows because of their capacity of varying the throughput of visible light and solar energy. This study highlights the evolution of structural and morphological changes of electrodeposited WO{sub 3} thin films coated with polypyrrole (PPy) by using chemical bath deposition. The structural and surface properties of WO{sub 3} thin films were studied using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrochemical stability was inspected using repetitive cyclic voltammetry (CV) cycles for each sample in LiClO{sub 4}-PC electrolyte for prolonged periods. The results showed an improvement in the electrochemical stability after the CV study. - Graphical abstract: Mechanism: A schematic of the mechanism is proposed in above fig. The mechanism is based on three step process: (i) WO{sub 3} coated on ITO by electrodeposition followed by thermal treatment. It produces ordered nanoarrayed morphology. (ii) A second step involving deposition of PPy by chemical bath deposition on ITO. It possesses globular morphology. (iii) When PPy coated on WO{sub 3}, PPy applies shearing force on WO{sub 3} and produces disordered nanoarrayed morphology. - Highlights: • Nanoarrayed WO{sub 3}/PPy composite was synthesized. • Interplanar spacing enhances due to PPy coating. • PPy applies shearing force on WO{sub 3} produces disordered morphology. • Nanocomposite showed high stability in LiClO{sub 4}-PC.

Studies on conducting polymer and conducting polymerinorganic composite electrodes prepared via a new cathodic polymerization method

Science.gov (United States)

Singh, Nikhilendra

A novel approach for the electrodeposition of conducting polymers and conducting polymer-inorganic composite materials is presented. The approach shows that conducting polymers, such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) can be electrodeposited by the application of a cathodic bias that generates an oxidizing agent, NO+, via the in-situ reduction of nitrate anions. This new cathodic polymerization method allows for the deposition of PPy and PEDOT as three dimensional, porous films composed of spherical polymer particles. The method is also suitable for the co-deposition of inorganic species producing conducting polymer-inorganic composite electrodes. Such composites are used as high surface area electrodes in Li-ion batteries, electrochemical hydrogen evolution and in the development of various other conducting polymer-inorganic composite electrodes. New Sn-PPy and Sb-PPy composite electrodes where Sn and Sb nanoparticles are well dispersed among the PPy framework are reported. These structures allow for decreased stress during expansion and contraction of the active material (Sn, Sb) during the alloying and de-alloying processes of a Li-ion battery anode, significantly alleviating the loss of active material due to pulverization processes. The new electrochemical synthesis mechanism allows for the fabrication of Sn-PPy and Sb-PPy composite electrodes directly from a conducting substrate and eliminates the use of binding materials and conducting carbon used in modern battery anodes, which significantly simplifies their fabrication procedures. Platinum (Pt) has long been identified as the most efficient catalyst for electrochemical water splitting, while nickel (Ni) is a cheaper, though less efficient alternative to Pt. A new morphology of PPy attained via the aforementioned cathodic deposition method allows for the use of minimal quantities of Pt and Ni dispersed over a very high surface area PPy substrate. These composite electrodes

A new thin film deposition process by cathodic plasma electrolysis

International Nuclear Information System (INIS)

Paulmier, T.; Kiriakos, E.; Bell, J.; Fredericks, P.

2004-01-01

Full text: A new technique, called atmospheric pressure plasma deposition (APPD), has been developed since a few years for the deposition of carbon and DLC, Titanium or Silicon films on metal and metal alloys substrates. A high voltage (2kV) is applied in a liquid electrolytic solution between an anode and a cathode, both electrodes being cylindrical: a glow discharge is then produced and confined at the vicinity of the cathode. The physic of the plasma in the electrolytic solution near the cathode is very different form the other techniques of plasma deposition since the pressure is here close to the atmospheric pressure. We describe here the different physico-chemical processes occurring during the process. In this cathodic process, the anodic area is significantly larger than the cathode area. In a first step, the electrolytic solution is heated by Joule effect induced by the high voltage between the electrodes. Due to the high current density, the vaporization of the solution occurs near the cathode: a large amount of bubbles are produced which are stabilized at the electrode by hydrodynamic and electromagnetic forces, forming a vapour sheath. The electric field and voltage drop are then concentrated in this gas envelope, inducing the ionization of the gas and the ignition of a glow discharge at the surface of the material. This plasma induces the formation of ionized and reactive species which diffuse and are accelerated toward the cathode. These excited species are the precursors for the formation of the deposition material. At the same time, the glow discharge interacts with the electrolyte solution inducing also ionization, convection and polymerization processes in the liquid: the solution is therefore a second source of the deposition material. A wide range of films have been deposited with a thickness up to 10 micrometers. These films have been analyzed by SEM and Raman spectroscopy. The electrolytic solution has been characterized by GC-MS and the

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.

Structural and electrochemical studies of PPy/PEG-LiFePO4 cathode material for Li-ion batteries

International Nuclear Information System (INIS)

Fedorkova, Andrea; Nacher-Alejos, Ana; Gomez-Romero, Pedro; Orinakova, Renata; Kaniansky, Dusan

2010-01-01

A simple chemical oxidative polymerization of pyrrole (Py) directly onto the surface of LiFePO 4 particles was applied to the synthesis of polypyrrole-LiFePO 4 (PPy-LiFePO 4 ) powder. The LiFePO 4 sample without carbon coating was synthesized by a solvothermal method. The polyethylene glycol (PEG) was used as additive during Py polymerization for increasing the PPy-LiFePO 4 conductivity. Properties of resulting LiFePO 4 , PPy-LiFePO 4 and PPy/PEG-LiFePO 4 samples were characterized by XRD, SEM, TGA and galvanostatic charge-discharge measurements. These methods confirmed the presence of polypyrrole on LiFePO 4 particles and its homogeneous distribution in the resulting powder material. The PPy/PEG-LiFePO 4 composites show higher discharge capacity than pure LiFePO 4 , as PPy/PEG network improves the electron conductivity. It presents specific discharge capacity of 153 mAh/g at C/5 rate.

Electrochemical impedance spectroscopy investigation on indium tin oxide films under cathodic polarization in NaOH solution

International Nuclear Information System (INIS)

Gao, Wenjiao; Cao, Si; Yang, Yanze; Wang, Hao; Li, Jin; Jiang, Yiming

2012-01-01

The electrochemical corrosion behaviors of indium tin oxide (ITO) films under the cathodic polarization in 0.1 M NaOH solution were investigated by electrochemical impedance spectroscopy. The as-received and the cathodically polarized ITO films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction for morphological, compositional and structural studies. The results showed that ITO films underwent a corrosion process during the cathodic polarization and the main component of the corrosion products was body-centered cubic indium. The electrochemical impedance parameters were related to the effect of the cathodic polarization on the ITO specimens. The capacitance of ITO specimens increased, while the charge transfer resistance and the inductance decreased with the increase of the polarization time. The proposed mechanism indicated that the corrosion products (metallic indium) were firstly formed during the cathodic polarization and then absorbed on the surface of the ITO film. As the surface was gradually covered by indium particles, the corrosion process was suppressed. - Highlights: ► Cathodic polarization of indium tin oxide (ITO) in 0.1 M NaOH. ► Cathodic polarization studied with electrochemical impedance spectroscopy. ► ITO underwent a corrosion attack during cathodic polarization, indium was observed. ► Electrochemical parameters of ITO were obtained using equivalent electrical circuit. ► A corrosion mechanism is proposed.

Structural, optical and electrical properties of CeO2 thin films simultaneously prepared by anodic and cathodic electrodeposition

Science.gov (United States)

Yang, Yumeng; Du, Xiaoqing; Yi, Chenxi; Liu, Jiao; Zhu, Benfeng; Zhang, Zhao

2018-05-01

CeO2 thin films were deposited on stainless steel (SS) and indium tin oxide (ITO)-coated glass by simultaneous anodic and cathodic electrodeposition, and the influence of negative potential on the formation of ceria films was studied with scanning electron microscopy, X-ray diffraction, Raman spectroscopy, van der Pauw measurements, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show that CeO2 films on the anode are slightly affected by the potential, but the particle size, crystal orientation, strain, film thickness, resistivity and Ce(III) content of the films on the cathode increases with increasing potential on the SS substrate. Contradictory to the results of the SS cathode, redshift (Ed changed from 3.95 eV to 3.56 eV and Ei changed from 3.42 eV to 3.04 eV) occurring in the absorption spectrum of CeO2 deposited on the ITO-coated glass cathode indicates that the content of Ce3+ in the cathodic films is dependent on the adopted substrates and decreases as the applied potential is increased.

Development of alloy-film coated dispenser cathode for terahertz vacuum electron devices application

International Nuclear Information System (INIS)

Barik, R.K.; Bera, A.; Raju, R.S.; Tanwar, A.K.; Baek, I.K.; Min, S.H.; Kwon, O.J.; Sattorov, M.A.; Lee, K.W.; Park, G.-S.

2013-01-01

High power terahertz vacuum electron devices demand high current density and uniform emission dispenser cathode. It was found that the coating of noble metals e.g., Os, Ir, and Re on the surface of tungsten dispenser cathodes enhances the emission capabilities and uniformity. Hence metal coated cathode might be the best candidate for terahertz devices applications. In this study, ternary-alloy-film cathode (2Os:2Re:1 W) and Os coated cathode have been developed and the results are presented. The cathodes made out of this alloy coating showed 1.5 times higher emission and 0.02 eV emission uniformity as compared to those of simply Os coated cathodes which can be used in terahertz devices application.

Development of alloy-film coated dispenser cathode for terahertz vacuum electron devices application

Energy Technology Data Exchange (ETDEWEB)

Barik, R. K.; Bera, A. [School of Electrical Engineering and Computer Science, Seoul National University, Seoul (Korea, Republic of); Raju, R. S. [Central Electronics Engineering Research Institute (CEERI), Rajasthan (India); Tanwar, A. K.; Baek, I. K.; Min, S. H.; Kwon, O. J.; Sattorov, M. A. [Department of Physics and Astronomy, Center for THz-Bio Application Systems, and Seoul-Teracom Inc., Seoul National University, Seoul (Korea, Republic of); Lee, K. W. [LIG Nex1, Seoul (Korea, Republic of); Park, G.-S., E-mail: gunsik@snu.ac.kr [School of Electrical Engineering and Computer Science, Seoul National University, Seoul (Korea, Republic of); Department of Physics and Astronomy, Center for THz-Bio Application Systems, and Seoul-Teracom Inc., Seoul National University, Seoul (Korea, Republic of); Advanced Institute of Convergence Technology, Suwon-si, Gyeonggi-do (Korea, Republic of)

2013-07-01

High power terahertz vacuum electron devices demand high current density and uniform emission dispenser cathode. It was found that the coating of noble metals e.g., Os, Ir, and Re on the surface of tungsten dispenser cathodes enhances the emission capabilities and uniformity. Hence metal coated cathode might be the best candidate for terahertz devices applications. In this study, ternary-alloy-film cathode (2Os:2Re:1 W) and Os coated cathode have been developed and the results are presented. The cathodes made out of this alloy coating showed 1.5 times higher emission and 0.02 eV emission uniformity as compared to those of simply Os coated cathodes which can be used in terahertz devices application.

Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

CERN Document Server

Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

2002-01-01

The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

Cathodic reduction of the duplex oxide films formed on copper in air with high relative humidity at 60 deg C

International Nuclear Information System (INIS)

Seo, M.; Ishikawa, Y.; Kodaira, M.; Sugimoto, A.; Nakayama, S.; Watanabe, M.; Furuya, S.; Minamitani, R.; Miyata, Y.; Nishikata, A.; Notoya, T.

2005-01-01

The cathodic reduction of duplex air-formed oxide film on copper was performed at a constant current density of i c = -50 μA cm -2 in deaerated 0.1 M KCl solution to investigate the sequence of cathodic reduction of each oxide layer and its mechanism. The single-phase thick CuO film on copper was also cathodically reduced at i c = -50 μA cm -2 or -2.5 mA cm -2 . The surface characterizations of the air-formed oxide film and single-phase CuO film before cathodic reduction and after partial or complete cathodic reduction were performed by XPS and X-ray diffraction, respectively. The two plateau regions appeared in the potential vs. time curve during cathodic reduction of the duplex air-formed oxide film on copper, while one plateau region was observed in the potential-time curve during cathodic reduction of the single-phase CuO film on copper. The potential in the first plateau region for the air-formed film coincided with that in the plateau region for the CuO film. The results of XPS and X-ray diffraction suggested that in the first plateau region, the outer CuO layer is directly reduced to metallic Cu, while in the second plateau region, the inner Cu 2 O layer is reduced to metallic Cu

Organization of film data processing in the PPI-SA automated system

International Nuclear Information System (INIS)

Ovsov, Yu.V.; Perekatov, V.G.

1984-01-01

Organization of processing nuclear interaction images at PUOS - type standard devices using the PPI-SA automated system is considered. The system is made in the form of a complete module comprising two scanning measuring projectors and a scan-ning automatic device which operate in real time on line with the BESM-4-computer. The system comprises: subsystem for photographic film scanning, selection of events for measurements and preliminary encoding; subsystem for formation and generation of libraries with data required for monitoring the scanning automatic device; subsystem for precision measurements separate coordinates on photo images of nuclear particle tracks and ionization losses. The system software comprises monitoring programs for the projectors and scanning automatic device as well as test functional control programs and operating system. The programs are organized a modular concept. By changing the module set the system can be modified and adapted for image processing in different fields of science and technology

Synthesis of Poly pyrrole Inverse Opal in [bmim] Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

International Nuclear Information System (INIS)

Yan, W.; Dong, Q.Q.; Sun, L.N.; Deng, W.; Wu, Sh.

2013-01-01

Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered poly pyrrole (PPy) inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF 6 . PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS) were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF 6 - anions kept de doping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF 6 - anions also kept de doping from the PPy inverse opals, the PO 4 3- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours

Synthesis of Polypyrrole Inverse Opal in [bmim]PF6- Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

Directory of Open Access Journals (Sweden)

Wei Yan

2013-01-01

Full Text Available Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered polypyrrole (PPy inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF6. PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF6- anions kept dedoping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF6- anions also kept dedoping from the PPy inverse opals, the PO43- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours.

Nano-silver mediated polymerization of pyrrole: synthesis and gas sensing properties of polypyrrole (PPy)/Ag nano-composite.

Science.gov (United States)

Kate, Kunal H; Damkale, Shubhangi R; Khanna, P K; Jain, G H

2011-09-01

Thermal polymerization of pyrrole was performed using silver nitrate as source of silver ions followed by its conversion to Polypyrrole (PPy)/Ag nano-comoposites without using any external oxidizing agent or solvent. The formation of PPy was monitored by UV-Visible absorption spectroscopy showing a band at approximately 464 nm. XRD measurement confirmed characteristic peaks for face centered cubic (fcc) silver and presence of PPy at 2 theta of approximately 23 degrees suggesting the formation of PPy/Ag nanocomposite. Transmission electron microscopy (TEM) images showed non-aggregated spherical Ag nano-particles of about 5-10 nm. PPy/Ag thick film acts as a NH3 sensor at 100 degrees C, a H2S sensor at 250 degrees C and CO2 sensor at 350 degrees C. The thick films showed capability to recognize various gases at different operating temperature.

The change of pH under a paint film due to cathodic protection

NARCIS (Netherlands)

Gellings, P.J.; Ekama, H.C.

1975-01-01

The diffusion of OH−-ions and H2 formed during cathodic protection through a paint film is studied. The diffusion equation is solved for non-stationary conditions and from this the steady state is also derived. It is shown that under usual operating conditions of cathodic protection of ships the

Heat treatment of cathodic arc deposited amorphous hard carbon films

Energy Technology Data Exchange (ETDEWEB)

Anders, S.; Ager, J.W. III; Brown, I.G. [and others

1997-02-01

Amorphous hard carbon films of varying sp{sup 2}/sp{sup 3} fractions have been deposited on Si using filtered cathodic are deposition with pulsed biasing. The films were heat treated in air up to 550 C. Raman investigation and nanoindentation were performed to study the modification of the films caused by the heat treatment. It was found that films containing a high sp{sup 3} fraction sustain their hardness for temperatures at least up to 400 C, their structure for temperatures up to 500 C, and show a low thickness loss during heat treatment. Films containing at low sp{sup 3} fraction graphitize during the heat treatment, show changes in structure and hardness, and a considerable thickness loss.

Pedot and PPy Conducting Polymer Bilayer and Trilayer Actuators

DEFF Research Database (Denmark)

Zainudeen, Umer Lebbe; Careem, Mohamed Abdul; Skaarup, Steen

2008-01-01

attempts have been made to improve the actuator performance. We report electromechanical measurements on actuators of bilayer and trilayer free standing films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers. Both types of conducting polymer are pre...

Study of nanometric thin pyrolytic carbon films for explosive electron emission cathode in high-voltage planar diode

Energy Technology Data Exchange (ETDEWEB)

Baryshevsky, Vladimir; Belous, Nikolai; Gurinovich, Alexandra; Gurnevich, Evgeny [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Kuzhir, Polina, E-mail: polina.kuzhir@gmail.com [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Maksimenko, Sergey [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Molchanov, Pavel; Shuba, Mikhail [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Roddatis, Vladimir [CIC energiGUNE, Albert Einstein 48, 01510 Minano, Alava (Spain); Institut für Materialphysik of Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Kaplas, Tommi; Svirko, Yuri [Institute of Photonics, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101 (Finland)

2015-04-30

We report on an experimental study of explosive electron emission properties of cathode made by nanometric thin pyrolytic carbon (PyC) films (2–150 nm) deposited on Cu substrate via methane-based chemical vapor deposition. High current density at level of 300 A/cm{sup 2} in 5 · 10{sup −5} Pa vacuum has been observed together with very stable explosive emission from the planar cathode. The Raman spectroscopy investigation proves that the PyC films remain the same after seven shots. According to the optical image analysis of the cathode before and after one and seven shots, we conclude that the most unusual and interesting feature of using the PyC films/Cu cathode for explosive emission is that the PyC layer on the top of the copper target prevents its evaporation and oxidation, which leads to higher emission stability compared to conventional graphitic/Cu cathodes, and therefore results in longer working life. - Highlights: • Explosive electron emission from pyrolytic carbon (PyC) cathode is reported. • We observe high current density, 300 A/cm{sup 2}, and stable emission parameters. • PyC integrity ensures a high application potential for high current electronics.

Surprising volume change in PPy(DBS): An atomic force microscopy study

DEFF Research Database (Denmark)

Smela, E.; Gadegaard, N.

1999-01-01

Communication: Conjugated polymers such as polypyrrole (PPy) have potential use as artificial muscles or in microsystems such as valves for micro-fluid handling. One of the most important parameters in such uses is the magnitude of volume change during associated redox processes; however, until now...... estimates have varied greatly. Atomic force microscopy is reported here as allowing direct measurement of the in situ thickness change during oxidation and reduction of thin films of PPy doped with dodecylbenzenesulfonate....

Vacuum arc plasma generation and thin film deposition from a TiB{sub 2} cathode

Energy Technology Data Exchange (ETDEWEB)

Zhirkov, Igor, E-mail: igozh@ifm.liu.se; Petruhins, Andrejs; Naslund, Lars-Ake; Rosen, Johanna [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Kolozsvári, Szilard; Polcik, Peter [PLANSEE Composite Materials GmbH, Siebenbürgerstraße 23, 86983 Lechbruck am See (Germany)

2015-11-02

We have studied the utilization of TiB{sub 2} cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of metal borides.

A FED Prototype Using Patterned DLC Thin Films as the Cathode

Science.gov (United States)

Li, W.; Feng, T.; Mao, D. S.; Wang, X.; Liu, X. H.; Zou, S. C.; Zhu, Y. K.; Li, Q.; Xu, J. F.; Jin, S.; Zheng, J. S.

In our study, diamond-like-carbon (DLC) thin films were prepared by filtered arc deposition (FAD), which provided a way to deposit DLC thin films on large areas at room temperature. Glass slides coated 100nm chromium or titanium thin films were used as cathode substrates. Millions of rectangular holes with sizes of 5 × 5μm were made on the DLC films using a routine patterning process. Here a special reactive ion beam etching method was applied to etch the DLC films. The anodes of the devices were made by electrophoretic deposition. ZnO:Zn phosphor (P15) was employed, which has a broad band bluish green (centered at 490nm). Before electrophoretic deposition, the anode substrates (ITO glass slides) had been patterned into 50 anode electrodes. In order to improve the adherence of phosphor layers, the as-deposited screens were treated in Na2SiO3 solution for 24h to add additional binder. A kind of matrix-addressed diode FED prototype was designed and packaged. 50-100μm-thick glass slides were used as spacers and getters were applied to maintain the vacuum after the exhaustion. The applied DC voltage was ranged in 0-3000V and much higher current density was measured in the cathode-patterned prototypes than the unpatterned ones during the test. As a result, characters could be well displayed.

Nanocrystalline diamond film as cathode for gas discharge sensors

Energy Technology Data Exchange (ETDEWEB)

Jou, Shyankay, E-mail: sjou@mail.ntust.edu.t [Graduate Institute of Materials Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Huang, Bohr-Ran [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Wu, Meng-Chang [Department of Electronic Engineering, National Yunlin University of Science and Technology, Touliu 640, Taiwan (China)

2010-05-31

Nanocrystalline diamond (NCD) film was deposited on a silicon substrate utilizing microwave plasma-enhanced chemical vapor deposition in a mixed flow of methane, hydrogen and argon. The deposited film had a cauliflower-like morphology, and was composed of NCD, carbon clusters and mixed sp{sup 2}- and sp{sup 3}-bonded carbon. Electron field emission (EFE) in vacuum and electrical discharges in Ar, N{sub 2} and O{sub 2} using the NCD film as the cathode were characterized. The turn-on field for EFE and the geometric enhancement factor for the NCD film were 8.5 V/{mu}m and 668, respectively. The breakdown voltages for Ar, N{sub 2} and O{sub 2} increased with pressures from 1.33 x 10{sup 4} Pa to 1.01 x 10{sup 5} Pa, following the right side of the normal Paschen curve.

Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

Science.gov (United States)

Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

2012-02-01

Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate.

Modification of low temperature deposited LiMn2O4 thin film cathodes by oxygen plasma irradiation

International Nuclear Information System (INIS)

Chen, Chen Chung; Chiu, Kuo-Feng; Lin, Kun Ming; Lin, Hsin Chih

2009-01-01

Lithium manganese oxides have been deposited by radio frequency magnetron sputter deposition with relatively lower annealing temperatures and then post-treated with a radio frequency (rf) driven oxygen plasma. Following oxygen plasma irradiation, the film properties were modified, and the performance of the thin film cathode has been enhanced. The electrochemical properties of the treated thin-film cathodes were characterized and compared. The results showed that the samples with moderate plasma treatment also maintained good cyclic properties as cycled at a wide range potential window of 2.0 V-4.5 V. Its electrochemical properties were significantly improved by this process, even though the films were prepared under low annealing temperature.

Conductive framework of inverse opal structure for sulfur cathode in lithium-sulfur batteries.

Science.gov (United States)

Jin, Lu; Huang, Xiaopeng; Zeng, Guobo; Wu, Hua; Morbidelli, Massimo

2016-09-07

As a promising cathode inheritor for lithium-ion batteries, the sulfur cathode exhibits very high theoretical volumetric capacity and energy density. In its practical applications, one has to solve the insulating properties of sulfur and the shuttle effect that deteriorates cycling stability. The state-of-the-art approaches are to confine sulfur in a conductive matrix. In this work, we utilize monodisperse polystyrene nanoparticles as sacrificial templates to build polypyrrole (PPy) framework of an inverse opal structure to accommodate (encapsulate) sulfur through a combined in situ polymerization and melting infiltration approach. In the design, the interconnected conductive PPy provides open channels for sulfur infiltration, improves electrical and ionic conductivity of the embedded sulfur, and reduces polysulfide dissolution in the electrolyte through physical and chemical adsorption. The flexibility of PPy and partial filling of the inverse opal structure endure possible expansion and deformation during long-term cycling. It is found that the long cycling stability of the cells using the prepared material as the cathode can be substantially improved. The result demonstrates the possibility of constructing a pure conductive polymer framework to accommodate insulate sulfur in ion battery applications.

Effect of N{sub 2} and Ar gas on DC arc plasma generation and film composition from Ti-Al compound cathodes

Energy Technology Data Exchange (ETDEWEB)

Zhirkov, Igor, E-mail: igozh@ifm.liu.se; Rosen, Johanna [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Oks, Efim [Institute of High Current Electronics SB RAS, 2/3 Akademichesky Avenue, 634055 Tomsk (Russian Federation)

2015-06-07

DC arc plasma from Ti, Al, and Ti{sub 1−x}Al{sub x} (x = 0.16, 0.25, 0.50, and 0.70) compound cathodes has been characterized with respect to plasma chemistry (charged particles) and charge-state-resolved ion energy for Ar and N{sub 2} pressures in the range 10{sup −6} to 3 × 10{sup −2} Torr. Scanning electron microscopy was used for exploring the correlation between the cathode and film composition, which in turn was correlated with the plasma properties. In an Ar atmosphere, the plasma ion composition showed a reduction of Al of approximately 5 at. % compared to the cathode composition, while deposited films were in accordance with the cathode stoichiometry. Introducing N{sub 2} above ∼5 × 10{sup −3} Torr, lead to a reduced Al content in the plasma as well as in the film, and hence a 1:1 correlation between the cathode and film composition cannot be expected in a reactive environment. This may be explained by an influence of the reactive gas on the arc mode and type of erosion of Ti and Al rich contaminations, as well as on the plasma transport. Throughout the investigated pressure range, a higher deposition rate was obtained from cathodes with higher Al content. The origin of generated gas ions was investigated through the velocity rule, stating that the most likely ion velocities of all cathode elements from a compound cathode are equal. The results suggest that the major part of the gas ions in Ar is generated from electron impact ionization, while gas ions in a N{sub 2} atmosphere primarily originate from a nitrogen contaminated layer on the cathode surface. The presented results provide a contribution to the understanding processes of plasma generation from compound cathodes. It also allows for a more reasonable approach to the selection of composite cathode and experimental conditions for thin film depositions.

Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

Science.gov (United States)

Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

2011-03-01

Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

Mechanical, barrier and morphological properties of pea starch and peanut protein isolate blend films.

Science.gov (United States)

Sun, Qingjie; Sun, Cuixia; Xiong, Liu

2013-10-15

Mechanical, barrier and morphological properties of edible films based on blends of Pea starch (PS) and Peanut protein isolate (PPI) plasticized with glycerol (30%, w/w) were investigated. As PPI ratio in PS/PPI blends increased, the thickness of films decreased, the opacity slightly elevated and color intensified. The addition of PPI to the PS film significantly reduced tensile strength from 5.44 MPa to 3.06 MPa, but increased elongation from 28.56% to 98.12% with the incorporation of PPI into PS at 50% level. Film solubility value fell from 22.31% to 9.78% upon the incorporation of PPI ranged from 0 to 50% level. When PPI was added into PS film at 40% level, the WVP and WVTR of the films markedly dropped from 11.18% to 4.19% and 6.16 to 1.95%, respectively. Scanning electron microscopy (SEM) of the surface of films showed that many swollen starch granules were presented in the 100% PS film, while 100% PPI film was observed to have rougher surfaces with presence of pores or cavities. The PS/PPI blend films upon the incorporation of PPI at 20% and 50% level were not homogeneous. However, the smoother film surface was observed in PS/PPI blend films with the addition of PPI at 40% level. SEM image of the cross-sections of the films revealed that the 100% PS film showed a uniform and compact matrix without disruption, and pore formation and 100% PPI film displayed a smooth structure. Rougher and flexible network was shown in blend film with the addition of PPI reaching 40% level. Copyright © 2013. Published by Elsevier Ltd.

Lithium iron phosphate/carbon nanocomposite film cathodes for high energy lithium ion batteries

International Nuclear Information System (INIS)

Liu, Yanyi; Liu, Dawei; Zhang, Qifeng; Yu, Danmei; Liu, Jun; Cao, Guozhong

2011-01-01

This paper reports sol-gel derived nanostructured LiFePO4/carbon nanocomposite film cathodes exhibiting enhanced electrochemical properties and cyclic stabilities. LiFePO4/carbon films were obtained by spreading sol on Pt coated Si wafer followed by ambient drying overnight and annealing/pyrolysis at elevated temperature in nitrogen. Uniform and crack-free LiFePO4/carbon nanocomposite films were readily obtained and showed olivine phase as determined by means of X-Ray Diffractometry. The electrochemical characterization revealed that, at a current density of 200 mA/g (1.2 C), the nanocomposite film cathodes demonstrated an initial lithium-ion intercalation capacity of 312 mAh/g, and 218 mAh/g after 20 cycles, exceeding the theoretical storage capacity of conventional LiFePO4 electrode. Such enhanced Li-ion intercalation performance could be attributed to the nanocomposite structure with fine crystallite size below 20 nm as well as the poor crystallinity which provides a partially open structure allowing easy mass transport and volume change associated with Li-ion intercalation. Moreover the surface defect introduced by carbon nanocoating could also effectively facilitate the charge transfer and phase transitions.

Understanding of electrochemical and structural changes of polypyrrole/polyethylene glycol composite films in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Pirvu, Cristian, E-mail: c_pirvu@chim.pub.ro [University Polytechnic of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061 Bucharest (Romania); Manole, Claudiu Constantin; Stoian, Andrei Bogdan; Demetrescu, Ioana [University Polytechnic of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061 Bucharest (Romania)

2011-11-30

Highlights: > Electrochemical monitoring of PPy and PPy-PEG films over immersion time. > Electrochemical and surface analysis showed that PEG improves the stability of PPy films. > Mott-Schottky analysis reveals p-type conductance for both films. > In situ AFM analysis sustains electrochemical behaviour. > A model of PPy and PPy-PEG films behaviour during immersion was elaborated. - Abstract: Electrochemical monitoring of electrical and structural changes of both PPy and PPy-PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated. Electrochemical analysis suggests that PPy-PEG film inserts cations easier than PPy film for a short immersion time probably due to ability of PEG to form complexes with metal cations. The FTIR spectra showed that the PEG incorporation decreases the rate of PPy overoxidation probably by restraining the electron release and by rendering O{sub 2} inaccessible to PPy. Mott-Schottky analysis based on capacitance measurement reveal p-type conductance for both films. The in situ AFM analysis sustains electrochemical behaviour and has permitted elaboration of a model of PPy and PPy-PEG films behaviour during immersion in testing solution.

Synthesis and characterization of silver-polypyrrole film composite

Energy Technology Data Exchange (ETDEWEB)

Ayad, Mohamad M., E-mail: mayad12000@yahoo.com [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt); Zaki, Eman [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt)

2009-11-15

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO{sub 3}. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO{sub 3} solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Synthesis and characterization of silver-polypyrrole film composite

International Nuclear Information System (INIS)

Ayad, Mohamad M.; Zaki, Eman

2009-01-01

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3 . Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Synthesis and characterization of silver-polypyrrole film composite

Science.gov (United States)

Ayad, Mohamad. M.; Zaki, Eman

2009-11-01

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Selective formation of biphasic thin films of metal–organic frameworks by potential-controlled cathodic electrodeposition

OpenAIRE

Li, Minyuan Miller; Dinca, Mircea

2013-01-01

Cathodic electrodeposition lends itself to the formation of biphasic metal–organic framework thin films at room temperature from single deposition baths using potential bias as the main user input. Depending on the applied potential, we selectively deposit two different phases as either bulk mixtures or bilayer films.

Impregnated cathode coated with tungsten thin film containing Sc2O3

International Nuclear Information System (INIS)

Yamamoto, S.; Taguchi, S.; Watanabe, I.; Kawase, S.

1987-01-01

An impregnated cathode of a novel structure is proposed, fabricated, and evaluated. A thin tungsten film 100--400 nm in thickness containing various amounts of Sc 2 O 3 is coated on a standard impregnated cathode composed of a porous tungsten body in which electron emissive materials are impregnated. The electron emission property measured with a diode configuration is found to be dependent on Sc 2 O 3 content and surface atom distribution. Surface atom distribution is depicted by means of Auger electron spectroscopy. For high electron emission enhancement it is necessary for Sc 2 O 3 content to be 2.5--6.5 wt. % and for a layer of the order of a monolayer in thickness composed of Ba, Sc, and O to develop on the cathode surface

Influence of thermal heating on diamond-like carbon film properties prepared by filtered cathodic arc

International Nuclear Information System (INIS)

Khamnualthong, N.; Siangchaew, K.; Limsuwan, P.

2013-01-01

Tetrahedral amorphous diamond-like carbon (ta-DLC) films were deposited on magnetic recording heads using the filtered cathodic arc method. The deposited film thickness was on the order of several nanometers. The DLC films were then annealed to 100 °C–300 °C for 30 and 60 min, and the structure of the ta-DLC films was investigated using Raman spectroscopy, where the gross changes were observed in the Raman D and G peaks. Detailed interpretation concluded that there was sp 2 clustering as a function of temperature, and there was no sp 3 -to-sp 2 conversion after heating up to 300 °C. Furthermore, X-ray photoelectron spectroscopy suggested that oxidation of both the ta-DLC film and the adhesion layer occurs at 300 °C. Additionally, more film wear was observed with heating as measured by a nanoindenter. - Highlights: • Tetrahedral-amorphous diamond-like carbon (ta-DLC) by filtered cathodic arc • ta-DLC used in magnetic recording head as head overcoat • ta-DLC thickness range of less than 2 nm • ta-DLC property dependence on heating • Temperature effect range of up to 300 °C

Understanding of electrochemical and structural changes of polypyrrole/polyethylene glycol composite films in aqueous solution

International Nuclear Information System (INIS)

Pirvu, Cristian; Manole, Claudiu Constantin; Stoian, Andrei Bogdan; Demetrescu, Ioana

2011-01-01

Highlights: → Electrochemical monitoring of PPy and PPy-PEG films over immersion time. → Electrochemical and surface analysis showed that PEG improves the stability of PPy films. → Mott-Schottky analysis reveals p-type conductance for both films. → In situ AFM analysis sustains electrochemical behaviour. → A model of PPy and PPy-PEG films behaviour during immersion was elaborated. - Abstract: Electrochemical monitoring of electrical and structural changes of both PPy and PPy-PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated. Electrochemical analysis suggests that PPy-PEG film inserts cations easier than PPy film for a short immersion time probably due to ability of PEG to form complexes with metal cations. The FTIR spectra showed that the PEG incorporation decreases the rate of PPy overoxidation probably by restraining the electron release and by rendering O 2 inaccessible to PPy. Mott-Schottky analysis based on capacitance measurement reveal p-type conductance for both films. The in situ AFM analysis sustains electrochemical behaviour and has permitted elaboration of a model of PPy and PPy-PEG films behaviour during immersion in testing solution.

Thermal Measurement during Electrolysis of Pd-Ni Thin-film -Cathodes in Li2SO4/H2O Solution

Science.gov (United States)

Castano, C. H.; Lipson, A. G.; S-O, Kim; Miley, G. H.

2002-03-01

Using LENR - open type calorimeters, measurements of excess heat production were carried out during electrolysis in Li_2SO_4/H_2O solution with a Pt-anode and Pd-Ni thin film cathodes (2000-8000 Åthick) sputtered on the different dielectric substrates. In order to accurately evaluate actual performance during electrolysis runs in the open-type calorimeter used, considering effects of heat convection, bubbling and possible H_2+O2 recombination, smooth Pt sheets were used as cathodes. Pt provides a reference since it does not produce excess heat in the light water electrolyte. To increase the accuracy of measurements the water dissociation potential was determined for each cathode taking into account its individual over-voltage value. It is found that this design for the Pd-Ni cathodes resulted in the excess heat production of ~ 20-25 % of input power, equivalent to ~300 mW. In cases of the Pd/Ni- film fracture (or detachment from substrate) no excess heat was detected, providing an added reference point. These experiments plus use of optimized films will be presented.

Mitigating Backgrounds with a Novel Thin-Film Cathode in the DRIFT-IId Dark Matter Detector

Science.gov (United States)

Miller, Eric H.

The nature of dark matter, which comprises 85% of the matter density in the universe, is a major outstanding question in physics today. The standard hypothesis is that the dark matter is a new weakly interacting massive particle, which is present throughout the galaxy. These particles could interact within detectors on Earth, producing low-energy nuclear recoils. Two distinctive signatures arise from the solar motion through the galaxy. The DRIFT experiment aims to measure one of these, the directional signature that is based on the sidereal modulation of the nuclear recoil directions. Although DRIFT has demonstrated its capability for detecting this signature, it has been plagued by a large number of backgrounds that have limited its reach. The focus of this thesis is on characterizing these backgrounds and describing techniques that have essentially eliminated them. The background events in the DRIFT-IId detector are predominantly caused by alpha decays on the central cathode in which the alpha particles completely or partially absorbed by the cathode material. This thesis describes the installation a 0.9 mum thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on identifying and quantifying the sources of alpha decay backgrounds, as well as their contributions to the background rate in the detector. This in-situ study is based on alpha range spectroscopy and the determination of the absolute alpha detection efficiency. The results for the final radiologically clean version of the cathode give a contamination of 3.3 +/- 0.1 ppt 234U and 73 +/- 2 ppb 238U, and an efficiency for rejecting an RPR from an alpha decay that is a factor 70 +/- 20 higher than for the original wire cathode. Along with other background reduction measures, the thin-film cathode has reduced the observed background rate from 130/day to 1.7/day

Deposition of indium tin oxide thin films by cathodic arc ion plating

International Nuclear Information System (INIS)

Yang, M.-H.; Wen, J.-C.; Chen, K.-L.; Chen, S.-Y.; Leu, M.-S.

2005-01-01

Indium tin oxide (ITO) thin films have been deposited by cathodic arc ion plating (CAIP) using sintered oxide target as the source material. In an oxygen atmosphere of 200 deg. C, ITO films with a lowest resistivity of 2.2x10 -4 Ω-cm were obtained at a deposition rate higher than 450 nm/min. The carrier mobility of ITO shows a maximum at some medium pressures. Although morphologically ITO films with a very fine nanometer-sized structure were observed to possess the lowest resistivity, more detailed analyses based on X-ray diffraction are attempted to gain more insight into the factors that govern electron mobility in this investigation

Development of a novel biosensor based on a polypyrrole-dodecylbenzene sulphonate (PPy-DBS) film for the determination of amperometric cholesterol.

Science.gov (United States)

Özer, Bayram Oğuz; Çete, Servet

2017-06-01

Herein a novel amperometric biosensor based on a conducting polymer with anionic dopant modified electrode was successfully developed for detection of cholesterol. Polypyrrole is deposited on a platinum surface and the sodium dodecylbenzene sulphonate (DBS) ion-doped polypyrrole film was electrochemically prepared by scanning the electrode potential between -0.8 and +0.8 V at a scan rate of 20 mV/s. The present electrochemical biosensor was optimized in terms of working potential, number of cycles, concentrations of monomer, and anionic dopant. Cholesterol oxidase (ChOx) was physically entrapped in PPy-DBS to construct an amperometric cholesterol biosensor. Amperometric determination is based on the electrochemical detection of H 2 O 2 generated in the enzymatic reaction of cholesterol. Kinetic parameters, operational and storage stabilities, pH, and temperature dependencies were determined. Km and Imax were calculated as 0.11 μM and 0.967 nM/min, respectively. The operational stability results showed that 90.0% of the response current was retained after 30 activity assays. Morphology of electrodes was characterized by SEM and AFM. Additionally, contact angle measurements were made with 1 μL water of polymer film and enzyme electrode. As a result, the cholesterol biosensor suggested in this study is easy to prepare and is highly cost-effective. This composite (PPy-DBS) can supply a biocompatible and electrochemical microenvironment for immobilization of the enzyme, making this material a good candidate for the fabrication of highly sensitive and selective cholesterol biosensors.

Increased cathode performance using a thin film LSM layer on a structured 8YSZ electrolyte surface

Energy Technology Data Exchange (ETDEWEB)

Herbstritt, D.; Weber, A.; Ivers-Tiffee, E. [Karlsruhe Univ. (T.H.) (DE). Inst. fuer Werkstoffkunde der Elektrotechnik (IWE); Guntow, U.; Mueller, G. [Fraunhofer-Institut fuer Silicatforschung (ISC), Wuerzburg (Germany)

2000-07-01

A considerable part of the power losses in a SOFC single cell occurs due to the polarization resistance of the cathode/electrolyte interface. The resulting high cathodic overvoltage corresponds to an enhanced degradation of the cell. In case of a screen printed LSM cathode layer (LSM: La{sub 1-x}Sr{sub x}MnO{sub 3}) on a YSZ electrolyte substrate (YSZ: Y{sub 2}O{sub 3} stabilised ZrO{sub 2}) the cathodic reaction is generally assumed to be restricted to the three phase boundary (tpb) between cathode, oxidant and the electrolyte surface. The electrochemical active area was increased by a modification of the cathode/electrolyte interface. Single cells with a thin film LSM layer on a structured 8YSZ electrolyte showed a power output of about 0.95 W/cm{sup 2} at 0.7 V cell voltage (950 C; oxidant: air, 0.7 1/min; fuel: hydrogen, 0.5 1/min, 15% fuel utilization). (orig.)

The multilayered structure of ultrathin amorphous carbon films synthesized by filtered cathodic vacuum arc deposition

KAUST Repository

Wang, Na; Komvopoulos, Kyriakos

2013-01-01

The structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) deposition was investigated by high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoelectron

Characteristics of rapid-thermal-annealed LiCoO2 cathode film for an all-solid-state thin film microbattery

International Nuclear Information System (INIS)

Kim, Han-Ki; Yoon, Young Soo

2004-01-01

We report on the fabrication of a LiCoO 2 film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The LiCoO 2 films were grown by rf magnetron sputtering using a synthesized LiCoO 2 target in a [O 2 /(Ar+O 2 )] ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited LiCoO 2 film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed LiCoO 2 film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm2 μm. These results show the possibility of the RTA LiCoO 2 film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively

Experimental investigation on the motion of cathode spots in removing oxide film on metal surface by vacuum arc

International Nuclear Information System (INIS)

Shi Zongqian; Jia Shenli; Wang Lijun; Yuan Qingjun; Song Xiaochuan

2008-01-01

The motion of vacuum arc cathode spots has a very important influence on the efficiency of removing the oxide film on the metal surface. In this paper, the characteristics of cathode spot motion are investigated experimentally. Experiments were conducted in a detachable vacuum chamber with ac (50 Hz) arc current of 1 kA (rms). A stainless steel plate covered by an oxide layer was used as the cathode. The motion of cathode spots during the descaling process was photographed by a high-speed digital camera with an exposure time of 2 μs. Experimental results indicate that the motion of cathode spots is influenced by the interaction among individual cathode jets and the position of the anode as well as the surface condition. The waveform of arc voltage is also influenced by the motion of cathode spots

Effect of sputtered lanthanum hexaboride film thickness on field emission from metallic knife edge cathodes

Science.gov (United States)

Kirley, M. P.; Novakovic, B.; Sule, N.; Weber, M. J.; Knezevic, I.; Booske, J. H.

2012-03-01

We report experiments and analysis of field emission from metallic knife-edge cathodes, which are sputter-coated with thin films of lanthanum hexaboride (LaB6), a low-work function material. The emission current is found to depend sensitively on the thickness of the LaB6 layer. We find that films thinner than 10 nm greatly enhance the emitted current. However, cathodes coated with a thicker layer of LaB6 are observed to emit less current than the uncoated metallic cathode. This result is unexpected due to the higher work function of the bare metal cathode. We show, based on numerical calculation of the electrostatic potential throughout the structure, that the external (LaB6/vacuum) barrier is reduced with respect to uncoated samples for both thin and thick coatings. However, this behavior is not exhibited at the internal (metal/LaB6) barrier. In thinly coated samples, electrons tunnel efficiently through both the internal and external barrier, resulting in current enhancement with respect to the uncoated case. In contrast, the thick internal barrier in thickly coated samples suppresses current below the value for uncoated samples in spite of the lowered external barrier. We argue that this coating thickness variation stems from a relatively low (no higher than 1018 cm-3) free carrier density in the sputtered polycrystalline LaB6.

The influence of cathode excavation of cathodic arc evaporator on thickness uniformity and erosion products angle distribution

Directory of Open Access Journals (Sweden)

D. V. Duhopel'nikov

2014-01-01

Full Text Available Cathodic arc evaporators are used for coating with functional films. Prolonged or buttend evaporators may be used for this purposes. In butt-end evaporator the cathode spots move continuously on the cathode work surface and evaporate cathode material. High depth excavation profile forms on the cathode work surface while the thick coating precipitation (tens or hundreds of microns. The cathode excavation profile is shaped like a “cup” with high walls for electrostatic discharge stabilization systems with axial magnetic fields. Cathode spots move on the bottom of the “cup”. It is very likely that high “cup” walls are formed as a result of lasting work time influence on the uniformity of precipitated films.In the present work the influence of excavation profile walls height on the uniformity of precipitated coating was carried out. The high profile walls are formed due to lasting work of DC vacuum arc evaporator. The cathode material used for tests was 3003 aluminum alloy. The extended substrate was placed parallel to the cathode work surface. Thickness distribution along the substrate length with the new cathode was obtained after 6 hours and after 12 hours of continuous operation.The thickness distribution of precipitated coating showed that the cathode excavation has an influence on the angular distribution of the matter escaping the cathode. It can be clearly seen from the normalized dependence coating thickness vs the distance from the substrate center. Also the angular distribution of the matter flow from the cathode depending on the cathode working time was obtained. It was shown that matter flow from the cathode differs from the LambertKnudsen law. The more the cathode excavation the more this difference.So, cathode excavation profile has an influence on the uniformity of precipitated coating and it is necessary to take in account the cathode excavation profile while coating the thick films.

Field emission mechanism from a single-layer ultra-thin semiconductor film cathode

International Nuclear Information System (INIS)

Duan Zhiqiang; Wang Ruzhi; Yuan Ruiyang; Yang Wei; Wang Bo; Yan Hui

2007-01-01

Field emission (FE) from a single-layer ultra-thin semiconductor film cathode (SUSC) on a metal substrate has been investigated theoretically. The self-consistent quantum FE model is developed by synthetically considering the energy band bending and electron scattering. As a typical example, we calculate the FE properties of ultra-thin AlN film with an adjustable film thickness from 1 to 10 nm. The calculated results show that the FE characteristic is evidently modulated by varying the film thickness, and there is an optimum thickness of about 3 nm. Furthermore, a four-step FE mechanism is suggested such that the distinct FE current of a SUSC is rooted in the thickness sensitivity of its quantum structure, and the optimum FE properties of the SUSC should be attributed to the change in the effective potential combined with the attenuation of electron scattering

LiCoO.sub.2./sub. thin-film cathodes grown by RF sputtering

Czech Academy of Sciences Publication Activity Database

Prachařová, Jarmila; Přidal, Jiří; Bludská, Jana; Jakubec, Ivo; Vorlíček, Vladimír; Málková, Zuzana; Makris, D. T.; Giorgi, R.; Jastrabík, Lubomír

2002-01-01

Roč. 108, - (2002), s. 204-212 ISSN 0378-7753 R&D Projects: GA MŠk ME 305 Institutional research plan: CEZ:AV0Z1010914 Keywords : LiCoO 3 * thin-film cathodes * Li- ion batteries Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.777, year: 2002

A magenta polypyrrole derivatised with Methyl Red azo dye: synthesis and spectroelectrochemical characterisation

International Nuclear Information System (INIS)

Almeida, Andresa K.A.; Dias, Jéssica M.M.; Santos, Diego P.; Nogueira, Fred A.R.; Navarro, Marcelo; Tonholo, Josealdo; Lima, Dimas J.P.; Ribeiro, Adriana S.

2017-01-01

Highlights: • A pyrrole (Py) derivative functionalised with methyl red (MRPy) was synthesised. • MRPy was polymerised electrochemically in LiClO_4/CH_3CN with BFEE. • Electrochromic properties of PMRPy and PPy doped with methyl red (PPy/MR) were compared. • Colour of the PMRPy changes from magenta to yellow depending on the pH. • PMRPy films might be applicable in optoelectronic devices or in pH sensors. - Abstract: A pyrrole derivative bearing 2-(4-dimethylaminophenylazo)benzoic acid, also known as Methyl Red (MR), was prepared by a simple synthetic route, and electropolymerised onto ITO/glass electrodes in (C_4H_9)_4NBF_4/CH_3CN in presence of boron trifluoride diethyl etherate (BFEE). Films of polypyrrole (PPy) and PPy doped with MR (PPy/MR) were also deposited onto ITO/glass in order to compare their electrochromic properties with the films of PPy derivatised with MR. Cyclic voltammogram of the poly[3-(N-pyrrolyl)propyl 2-(4-dimethylaminophenylazo)benzoate] (PMRPy) film displayed a redox pair with anodic peak potential (Epa) at ca. 0.53 V and cathodic peak potential (Epc) at 0.25 V vs. Ag/Ag"+, corresponding to the polymer p-doping, whilst the PPy/MR film shows capacitive behaviour with a redox pair in the cathodic region (Epa = −0.36 V and Epc = −0.62 V), similar to the PPy film (Epa = −0.10 V, and Epc = −0.15 V), and an anodic wave in the same potential range of that for PMRPy film. The electrochromic properties of the PMRPy film, such as chromatic contrast (Δ%T = 34.2%), switching time (τ = 10 s) and stability (Δ%T = 15% at the 100th cycle), were enhanced relative to the PPy/MR and PPy films. However, the colour of the PMRPy film changed from yellow (-0.8 V) to magenta (E = 1.0 V) in the first cycle and became light magenta at −0.8 V in the subsequent cycles. PMRPy films were also investigated in phosphate buffer solution (PBS, 2.0 ≤ pH ≤ 9.0) and after exposure to HCl vapour, in which the colour varied from magenta at pH = 2.0 to

Performance of the Chemical and Electrochemical Composites of PPy/CNT as Electrodes in Type I Supercapacitors

Directory of Open Access Journals (Sweden)

S. C. Canobre

2015-01-01

Full Text Available Polypyrrole (PPy is one of the most studied conducting polymers and a very promising material for various applications such as lithium-ion secondary batteries, light-emitting devices, capacitors, and supercapacitors, owing to its many advantages, including good processability, easy handling, and high electronic conductivity. In this work, PPy films were chemically and electrochemically synthesized, both in and around carbon nanotubes (CNTs. The cyclic voltammograms of the device, composed of the electrochemically synthesized PPy/CNT composites as working and counter electrodes (Type I supercapacitor with p-type doping, showed a predominantly capacitive profile with low impedance values and good electrochemical stability, with the anodic charge remaining almost constant (11.38 mC, a specific capacitance value of 530 F g−1 after 50 charge and discharge cycles, and a coulombic efficiency of 99.2%. The electrochemically synthesized PPy/CNT composite exhibited better electrochemical properties compared to those obtained for the chemically synthesized composite. Thus, the electrochemically synthesized PPy/CNT composite is a promising material to be used as electrodes in Type I supercapacitors.

Cycling-induced degradation of LiCoO2 thin-film cathodes at elevated temperature

International Nuclear Information System (INIS)

Van Sluytman, J.S.; West, W.C.; Whitacre, J.F.; Alamgir, F.M.; Greenbaum, S.G.

2006-01-01

The cycle life of LiCoO 2 -based all solid-state thin-film cells has been studied at room temperature, and at elevated temperatures of 50, 100, and 150 deg. C. X-ray diffraction, as well as Raman analysis, has been used to complement the electrochemical data in examining structural and chemical changes. XRD and Raman spectroscopy data indicate that elevated temperature soaks of the thin-film batteries in the quiescent state causes no discernable changes in the LiCoO 2 cathode layer. However, when the thin-film batteries are cycled at elevated temperatures, decreases in average grain size of the LiCoO 2 film occur with dramatic concomitant charge and discharge capacity loss

Flexo-green Polypyrrole – Silver nanocomposite films for thermoelectric power generation

International Nuclear Information System (INIS)

Bharti, Meetu; Singh, Ajay; Samanta, Soumen; Debnath, A.K.; Aswal, D.K.; Muthe, K.P.; Gadkari, S.C.

2017-01-01

Graphical abstract: Flexible PPy-Ag films prepared via environment friendly photo-polymerization in aqueous medium exhibited a record figure-of-merit of ∼7.4 × 10 −3 at 335 K among reported PPy based composites due to unique combination of high electrical and low thermal conductivity with increasing content of Ag nanoparticles. A proto-type thermoelectric power generator exhibiting output voltage of 6 mV has been demonstrated using these flexible PPy-Ag films. - Highlights: • Polypyrrole-silver (PPy-Ag) nanocomposites films were prepared on flexible BOPET sheet. • Ag particles anchored between PPy chains improve electrical transport but suppress thermal transport. • This work demonstrates highest figure-of-merit (∼7.4 × 10 −3 at 335 K) among PPy based materials. • A prototype thermoelectric power generator exhibiting output voltage of 6 mV has been fabricated using PPy-Ag films. - Abstract: Conducting polymers offer various advantages over inorganic thermoelectric materials such as eco-friendliness, a reduced manufacturing cost, flexibility, low thermal conductivity and amenability to tuning of electrical properties through doping; have recently drawn much attention for conversion of low temperature waste heat (≤150 °C) into electricity. In this study, we investigated the thermoelectric properties of hybrid films of polypyrrole and silver (PPy-Ag). These films were prepared on biaxially oriented polyethylene terephthalate (BOPET) flexible substrates by eco-friendly one pot photo-polymerization method using aqueous solution of silver nitrate (AgNO 3 ) as photo initiator. Detailed characterization of the samples revealed that morphology of composite films reorganized with the change in AgNO 3 concentration during synthesis. Increasing AgNO 3 concentrations resulted in PPy films containing Ag nanoparticles, nanoclusters as well as macroclusters. With alteration in concentration and size of Ag particles in PPy matrix, it has been observed that the

Inkjet-Printed Porous Silver Thin Film as a Cathode for a Low-Temperature Solid Oxide Fuel Cell.

Science.gov (United States)

Yu, Chen-Chiang; Baek, Jong Dae; Su, Chun-Hao; Fan, Liangdong; Wei, Jun; Liao, Ying-Chih; Su, Pei-Chen

2016-04-27

In this work we report a porous silver thin film cathode that was fabricated by a simple inkjet printing process for low-temperature solid oxide fuel cell applications. The electrochemical performance of the inkjet-printed silver cathode was studied at 300-450 °C and was compared with that of silver cathodes that were fabricated by the typical sputtering method. Inkjet-printed silver cathodes showed lower electrochemical impedance due to their porous structure, which facilitated oxygen gaseous diffusion and oxygen surface adsorption-dissociation reactions. A typical sputtered nanoporous silver cathode became essentially dense after the operation and showed high impedance due to a lack of oxygen supply. The results of long-term fuel cell operation show that the cell with an inkjet-printed cathode had a more stable current output for more than 45 h at 400 °C. A porous silver cathode is required for high fuel cell performance, and the simple inkjet printing technique offers an alternative method of fabrication for such a desirable porous structure with the required thermal-morphological stability.

Packaged Au-PPy valves for drug delivery systems

Science.gov (United States)

Tsai, Han-Kuan A.; Ma, Kuo-Sheng; Zoval, Jim; Kulinsky, Lawrence; Madou, Marc

2006-03-01

The most common methods for the drug delivery are swallowing pills or receiving injections. However, formulations that control the rate and period of medicine (i.e., time-release medications) are still problematic. The proposed implantable devices which include batteries, sensors, telemetry, valves, and drug storage reservoirs provide an alternative method for the responsive drug delivery system [1]. Using this device, drug concentration can be precisely controlled which enhances drug efficiency and decreases the side effects. In order to achieve responsive drug delivery, a reliable release valve has to be developed. Biocompatibility, low energy consumption, and minimized leakage are the main requirements for such release method. A bilayer structure composed of Au/PPy film is fabricated as a flap to control the release valve. Optimized potentiostatic control to synthesize polypyrrole (PPy) is presented. The release of miniaturize valve is tested and showed in this paper. A novel idea to simultaneously fabricate the device reservoirs as well as protective packaging is proposed in this paper. The solution of PDMS permeability problem is also mentioned in this article.

Characterization of Ag-doped vanadium oxide (AgxV2O5) thin film for cathode of thin film battery

International Nuclear Information System (INIS)

Hwang, H.S.; Oh, S.H.; Kim, H.S.; Cho, W.I.; Cho, B.W.; Lee, D.Y.

2004-01-01

The effect of silver co-sputtering on the characteristics of amorphous V 2 O 5 films, grown by dc reactive sputtering, is investigated. The co-sputtering process influences the growth mechanism as well as the characteristics of the V 2 O 5 films. X-ray diffraction (XRD), Inductively coupled plasma-atomic emission spectrometry (ICP-AES), field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectrometry (XPS) results indicate that the microstructure of the V 2 O 5 films is affected by the rf power of the co-sputtered silver. In addition, an all-solid-state thin film battery with full cell structure of Li/LiPON/Ag x V 2 O 5 /Pt has been fabricated. It is found that the silver co-sputtered V 2 O 5 cathode film exhibits better cycle performance than an undoped one

Nitrate ions as cathodic alkalization promoters for the electro-assisted deposition of sol-gel thin films

Energy Technology Data Exchange (ETDEWEB)

Ding Shangzhi; Liu Liang [Department of Chemistry, Yuquan Campus, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Hu Jiming [Department of Chemistry, Yuquan Campus, Zhejiang University, Hangzhou, Zhejiang 310027 (China)], E-mail: kejmhu@zju.edu.cn; Zhang Jianqing; Cao Chunan [Department of Chemistry, Yuquan Campus, Zhejiang University, Hangzhou, Zhejiang 310027 (China); State Key Laboratory for Corrosion and Protection, Shenyang 110016 (China)

2008-08-15

Nitrate was used as a promoter to prepare dodecyltrimethoxysilane thin films on aluminum substrates. With the addition of nitrate into silane sol-gel precursors, the electro-assisted formation of silane films was facilitated, as indicated by electrochemical impedance spectroscopy, scanning electron microscopy and secondary-ion mass spectroscopy, due to the promotion in cathodic alkalization. However, an extra-high concentration of nitrate would be harmful because of the salting-out effect in precursors and the soluble nitrate remaining in silane films.

PPI, paradoxes and Plato: who's sailing the ship?

Science.gov (United States)

Ives, Jonathan; Damery, Sarah; Redwod, Sabi

2013-03-01

Over the last decade, patient and public involvement (PPI) has become a requisite in applied health research. Some funding bodies demand explicit evidence of PPI, while others have made a commitment to developing PPI in the projects they fund. Despite being commonplace, there remains a dearth of engagement with the ethical and theoretical underpinnings of PPI processes and practices. More specifically, while there is a small (but growing) body of literature examining the effectiveness and impact of PPI, there has been relatively little reflection on whether the concept/practice of PPI is internally coherent. Here, the authors unpick a 'paradox' within PPI, which highlights a tension between its moral and pragmatic motivations and its implementation. The authors argue that this 'professionalisation paradox' means we need to rethink the practice, and purpose, of PPI in research.

Temperature dependence of the triplet diffusion and quenching rates in films of an Ir(ppy)3 -cored dendrimer

Science.gov (United States)

Ribierre, J. C.; Ruseckas, A.; Samuel, I. D. W.; Staton, S. V.; Burn, P. L.

2008-02-01

We study photoluminescence and triplet-triplet exciton annihilation in a neat film of a fac-tris(2-phenylpyridyl)iridium(III) [Ir(ppy)3] -cored dendrimer and in its blend with a 4,4' -bis( N -carbazolyl)biphenyl host for the temperature range of 77-300K . The nearest neighbor hopping rate of triplet excitons is found to increase by a factor of 2 with temperature between 150 and 300K and is temperature independent at lower temperature. The intermolecular quenching rate follows the Arrhenius law with an activation energy of 7meV , which can be explained by stronger dipole-dipole interactions with the donor molecule in the higher triplet substate. The results indicate that energy disorder has no significant effect on triplet transport and quenching in these materials.

Synthesis of aluminum nitride films by plasma immersion ion implantation-deposition using hybrid gas-metal cathodic arc gun

International Nuclear Information System (INIS)

Shen Liru; Fu, Ricky K.Y.; Chu, Paul K.

2004-01-01

Aluminum nitride (AlN) is of interest in the industry because of its excellent electronic, optical, acoustic, thermal, and mechanical properties. In this work, aluminum nitride films are deposited on silicon wafers (100) by metal plasma immersion ion implantation and deposition (PIIID) using a modified hybrid gas-metal cathodic arc plasma source and with no intentional heating to the substrate. The mixed metal and gaseous plasma is generated by feeding the gas into the arc discharge region. The deposition rate is found to mainly depend on the Al ion flux from the cathodic arc source and is only slightly affected by the N 2 flow rate. The AlN films fabricated by this method exhibit a cubic crystalline microstructure with stable and low internal stress. The surface of the AlN films is quite smooth with the surface roughness on the order of 1/2 nm as determined by atomic force microscopy, homogeneous, and continuous, and the dense granular microstructures give rise to good adhesion with the substrate. The N to Al ratio increases with the bias voltage applied to the substrates. A fairly large amount of O originating from the residual vacuum is found in the samples with low N:Al ratios, but a high bias reduces the oxygen concentration. The compositions, microstructures and crystal states of the deposited films are quite stable and remain unchanged after annealing at 800 deg. C for 1 h. Our hybrid gas-metal source cathodic arc source delivers better AlN thin films than conventional PIIID employing dual plasmas

Cathode and ion-luminescence of Eu:ZnO thin films prepared by reactive magnetron sputtering and plasma decomposition of non-volatile precursors

Energy Technology Data Exchange (ETDEWEB)

Gil-Rostra, Jorge [Instituto de Ciencia de Materiales de Sevilla, CSIC, Univ. Sevilla, C/Américo Vespucio 49, E-41092 Sevilla (Spain); Ferrer, Francisco J. [Centro Nacional de Aceleradores, CSIC, Univ. Sevilla, Av. Thomas A. Edison 7, E-41092 Sevilla (Spain); Martín, Inocencio R. [Departamento de Física Fundamental y Experimental, Electrónica y Sistemas, U. La Laguna, C/Astrofísico Francisco Sánchez s/n, E-38206 La Laguna, Santa Cruz de Tenerife (Spain); González-Elipe, Agustín R.; Yubero, Francisco [Instituto de Ciencia de Materiales de Sevilla, CSIC, Univ. Sevilla, C/Américo Vespucio 49, E-41092 Sevilla (Spain)

2016-10-15

This paper reports the luminescent behavior of Eu:ZnO thin films prepared by an one-step procedure that combines reactive magnetron sputtering deposition of ZnO with the plasma activated decomposition of a non-volatile acetylacetonate precursor of Eu sublimated in an effusion cell. Chemical composition and microstructure of the Eu:ZnO thin films have been characterized by several methods and their photo-, cathode- and ion-luminescent properties studied as a function of Eu concentration. The high transparency and well controlled optical properties of the films have demonstrated to be ideal for the development of cathode- and ion- luminescence sensors.

Protective Behavior of Poly(m-aminophenol) and Polypyrrole Coatings on Mild Steel

Science.gov (United States)

Yahaya, Sabrina M.; Harun, M. K.; Rosmamuhamadani, R.; Bonnia, N. N.; Ratim, S.

2018-01-01

Electrodeposition of polypyrrole (PPy) and poly (m-aminophenol) (PMAP) films on mild steel (MS) substrate was achieved in 0.3M oxalic acid solution and 0.3M NaOH, water:ethanol (70:30) solvent respectively using cyclic voltammetry technique. The morphology of the films constructed was determined by scanning electron microscope (SEM) while energy dispersive X-Ray analyzer (EDX) was used to establish the presence of organic PMAP and PPy film coating and its compositions. The corrosion performance of MS coated with both polymer films were investigated after 0.5 hours immersed in 0.5M NaCl aqueous solution by using polarization curves. It was found that PPy coating provides anodic protection while PMAP coating provides cathodic protection towards corrosion protection of mild steel substrate.

Fabrication of a large area cathode-supported thin electrolyte film for solid oxide fuel cells via tape casting and co-sintering techniques

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wen, Tinglian [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2009-04-15

A large area cathode-supported electrolyte film, comprising porous (La{sub 0.8}Sr{sub 0.2}){sub 0.95}MnO{sub 3} (LSM95) cathode substrate, LSM95/Zr{sub 0.89}Sc{sub 0.1}Ce{sub 0.01}O{sub 2-x} (SSZ) cathode active layer, and SSZ electrolyte, has been successfully fabricated by tape casting and co-sintering techniques. The interface reaction between cathode and electrolyte was inhibited by using A-site deficient LSM. A dense enough SSZ thin film with a thickness of {proportional_to}26 {mu}m was obtained at 1250 C. By using Pt as anode, the obtained single cell reached the maximum power density of 0.54 W cm{sup -2} at 800 C in O{sub 2}/humidified H{sub 2}, with open circuit voltage (OCV) value of 1.08 V. (author)

Praseodymium Cuprate Thin Film Cathodes for Intermediate Temperature Solid Oxide Fuel Cells: Roles of Doping, Orientation, and Crystal Structure.

Science.gov (United States)

Mukherjee, Kunal; Hayamizu, Yoshiaki; Kim, Chang Sub; Kolchina, Liudmila M; Mazo, Galina N; Istomin, Sergey Ya; Bishop, Sean R; Tuller, Harry L

2016-12-21

Highly textured thin films of undoped, Ce-doped, and Sr-doped Pr 2 CuO 4 were synthesized on single crystal YSZ substrates using pulsed laser deposition to investigate their area-specific resistance (ASR) as cathodes in solid-oxide fuel cells (SOFCs). The effects of T' and T* crystal structures, donor and acceptor doping, and a-axis and c-axis orientation on ASR were systematically studied using electrochemical impedance spectroscopy on half cells. The addition of both Ce and Sr dopants resulted in improvements in ASR in c-axis oriented films, as did the T* crystal structure with the a-axis orientation. Pr 1.6 Sr 0.4 CuO 4 is identified as a potential cathode material with nearly an order of magnitude faster oxygen reduction reaction kinetics at 600 °C compared to thin films of the commonly studied cathode material La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ . Orientation control of the cuprate films on YSZ was achieved using seed layers, and the anisotropy in the ASR was found to be less than an order of magnitude. The rare-earth doped cuprate was found to be a versatile system for study of relationships between bulk properties and the oxygen reduction reaction, critical for improving SOFC performance.

Preparation and enhanced electrochemical properties of nano-sulfur/poly(pyrrole-co-aniline) cathode material for lithium/sulfur batteries

International Nuclear Information System (INIS)

Qiu Linlin; Zhang Shichao; Zhang Lan; Sun, Mingming; Wang Weikun

2010-01-01

Poly(pyrrole-co-aniline) (PPyA) copolymer nanofibers were prepared by chemical oxidation method with cetyltrimethyl ammonium chloride (CTAC) as template, and the nano-sulfur/poly(pyrrole-co-aniline) (S/PPyA) composite material in lithium batteries was achieved via co-heating the mixture of PPyA and sublimed sulfur at 160 deg. C for 24 h. The component and structure of the materials were characterized by FTIR, Raman, XRD, and SEM. PPyA with nanofiber network structure was employed as a conductive matrix, adsorbing agent and firm reaction chamber for the sulfur cathode materials. The nano-dispersed composite exhibited a specific capacity up to 1285 mAh g -1 in the initial cycle and remained 866 mAh g -1 after 40 cycles.

Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

Science.gov (United States)

Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N.

Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 °C, after which the performance degraded with any further increase in temperature.

Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

Energy Technology Data Exchange (ETDEWEB)

Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N. [Center for Electrochemical Engineering, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

2008-09-15

Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 C, after which the performance degraded with any further increase in temperature. (author)

Cycling-induced degradation of LiCoO{sub 2} thin-film cathodes at elevated temperature

Energy Technology Data Exchange (ETDEWEB)

Van Sluytman, J.S.; Alamgir, F.M.; Greenbaum, S.G. [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10021 (United States); West, W.C.; Whitacre, J.F. [Electrochemical Technologies Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2006-04-01

The cycle life of LiCoO{sub 2}-based all solid-state thin-film cells has been studied at room temperature, and at elevated temperatures of 50, 100, and 150{sup o}C. X-ray diffraction, as well as Raman analysis, has been used to complement the electrochemical data in examining structural and chemical changes. XRD and Raman spectroscopy data indicate that elevated temperature soaks of the thin-film batteries in the quiescent state causes no discernible changes in the LiCoO{sub 2} cathode layer. However, when the thin-film batteries are cycled at elevated temperatures, decreases in average grain size of the LiCoO{sub 2} film occur with dramatic concomitant charge and discharge capacity loss. (author)

Surface modification of polyimide (PI) film using water cathode atmospheric pressure glow discharge plasma

International Nuclear Information System (INIS)

Zheng Peichao; Liu Keming; Wang Jinmei; Dai Yu; Yu Bin; Zhou Xianju; Hao Honggang; Luo Yuan

2012-01-01

Highlights: ► Equipment called water cathode atmospheric pressure glow discharge was used to improve the hydrophilicity of polyimide films. ► The data shows good homogeneity and the variation trends of contact angles are different for polar and non-polar testing liquids. ► The thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. ► Surface hydrophilicity after plasma treatment is improved partly due to the increase in the roughness. ► The hydrophilicity of polyimide films is still better than untreated ones after long-term storage. - Abstract: The industrial use of polyimide film is limited because of undesirable properties such as poor wettability. In the present paper, a new kind of equipment called water cathode atmospheric pressure glow discharge was used to improve the surface properties of polyimide films and made them useful to technical applications. The changes in hydrophilicity of modified polyimide film surfaces were investigated by contact angle, surface energy and water content measurements as a function of treatment time. The results obtained show good treatment homogeneity and that the variation trends of contact angles are different for polar and non-polar testing liquids, while surface energy and water content are significantly enhanced with the increase of treatment time until they achieve saturated values after 60 s plasma treatment. Also, the thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. Changes in morphology of polyimide films were analyzed by atomic force microscope and the results indicate that surface hydrophilicity after plasma treatment are improved partly due to the increase in the roughness. In addition, polyimide films treated by plasma are subjected to an ageing process to determine the durability of plasma treatment. It is found that the hydrophilicity is still better than untreated ones though the

CATHODIC ELECTRODEPOSITION OF Cu 4 SnS 4 THIN FILMS FROM ACIDIC SOLUTION

Directory of Open Access Journals (Sweden)

Anuar Kassim

2017-11-01

Full Text Available In this work the synthesis of copper tin sulfide thin films by electrodeposition is carried out. The films were deposited onto ITO glass substrates from anaqueous solution bath containingcopper sulfate, tin chloride and sodium thiosulfate at pH 1 and room temperature. Prior to the deposition, a cyclic voltammetry experiment was carried out between two potential limits (+1000 to -1000 mV versus Ag/AgCl to probe the effect of the applied potential and to determine the most likely suitable electrodeposition potential for the deposition of copper tin sulfide. The deposition was attempted at various cathodic potentials such as -400, -600, -800, -1000 mV to determine the optimum deposition potential. The films have been characterized by techniques such as optical absorption, X-ray diffraction and atomic force microscopy. The XRD patterns show that the films are polycrystalline with orthorhombic structure. The AFMstudies reveal the electrodeposited films were smooth, compact and uniform at deposition potentials of –600 mV versus Ag/AgCl. The direct optical band-gap energy was obtained to be 1.58 eV.

Corrosion properties of the Mg alloy coated with polypyrrole films

International Nuclear Information System (INIS)

Grubač, Zoran; Rončević, Ivana Škugor; Metikoš-Huković, Mirjana

2016-01-01

Highlights: • Electropolymerization of pyrrole on Mg-alloy surface in presence of salicylate. • Salicylate dual role in PPy deposition: passivation and electron transfer mediation. • Redox potential of salicylate corresponds to potential of PPy nucleation. • EIS and polarization corrosion studies of PPy coated Mg-alloy in Hanks’ solution. • Polypyrrole significantly slowdown Mg alloy corrosion in Hanks’ solution. - Abstract: In the present study the reactive surface of Mg alloy was coated with the nontoxic biocompatible polypyrrole (PPy) film synthesized by electrochemical oxidation from an aqueous salicylate solution. Salicylate ions prevent Mg dissolution and act as an electron transfer mediator during the PPy film nucleation, formation and growth on the alloy surface. Kinetics of the pyrrole polymerization as well as corrosion resistance of the PPy coated Mg alloy in the Hanks’ solution were investigated using dc electrochemical methods and electrochemical impedance spectroscopy (EIS). Characterization of the surface film was performed by optical and Fourier transform infrared spectroscopy (FTIR).

Coating for lithium anode, thionyl chloride active cathode electrochemical cell

Energy Technology Data Exchange (ETDEWEB)

Catanzarite, V.O.

1983-01-04

Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

Coating for lithium anode, thionyl chloride active cathode electrochemical cell

Energy Technology Data Exchange (ETDEWEB)

Catanzarite, V.O.

1981-10-20

Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

Raman Spectroscopy of DLC/a-Si Bilayer Film Prepared by Pulsed Filtered Cathodic Arc

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C. Srisang

2012-01-01

Full Text Available DLC/a-Si bilayer film was deposited on germanium substrate. The a-Si layer, a seed layer, was firstly deposited on the substrate using DC magnetron sputtering and DLC layer was then deposited on the a-Si layer using pulsed filtered cathodic arc method. The bilayer films were deposited with different DLC/a-Si thickness ratios, including 2/2, 2/6, 4/4, 6/2, and 9/6. The effect of DLC/a-Si thickness ratios on the sp3 content of DLC was analyzed by Raman spectroscopy. The results show that a-Si layer has no effect on the structure of DLC film. Furthermore, the upper shift in G wavenumber and the decrease in ID/IG inform that sp3 content of the film is directly proportional to DLC thickness. The plot modified from the three-stage model informed that the structural characteristics of DLC/a-Si bilayer films are located close to the tetrahedral amorphous carbon. This information may be important for analyzing and developing bilayer protective films for future hard disk drive.

Electrochemical characterization of a LiV3O8-polypyrrole composite as a cathode material for lithium ion batteries

International Nuclear Information System (INIS)

Tian Fanghua; Liu Li; Yang Zhenhua; Wang Xingyan; Chen Quanqi; Wang Xianyou

2011-01-01

Research highlights: → LiV 3 O 8 -PPy composite has been synthesized successfully. → LiV 3 O 8 -PPy composite shows better cycling behavior and rate capability than LiV 3 O 8 . → LiV 3 O 8 -PPy composite shows lower electrochemical resistance than LiV 3 O 8 . - Abstract: LiV 3 O 8 -Polypyrrole (LiV 3 O 8 -PPy) composite has been chemically synthesized by an oxidative polymerization of pyrrole monomer on the surface of LiV 3 O 8 using ferric chloride as oxidizing agent. The electrochemical properties of LiV 3 O 8 -PPy composite were systematically investigated using a variety of electrochemical methods. The LiV 3 O 8 -PPy composite electrode exhibited better cycling behavior and superior rate capability as compared with the bare LiV 3 O 8 electrode. Cyclic voltammetry corroborated the galvanostatic cycling tests, with the composite cathode material showing better reversibility than bare material. Finally, fitting the impedance results to an equivalent circuit indicated that the enhanced electrochemical performances of LiV 3 O 8 -PPy composite resulted from a facilitated kinetics of interfacial charge transfer in the presence of PPy.

Study of some structural properties of hydrogenated amorphous silicon thin films prepared by radiofrequency cathodic sputtering

International Nuclear Information System (INIS)

Mellassi, K.; Chafik El Idrissi, M.; Barhdadi, A.

2001-08-01

In this work, we have used the grazing X-rays reflectometry technique to characterise hydrogenated amorphous silicon thin films deposited by radio-frequency cathodic sputtering. Relfectometry measurements are taken immediately after films deposition as well as after having naturally oxidised their surfaces during a more or less prolonged stay in the ambient. For the films examined just after deposition, the role of hydrogen appears in the increase of their density. For those analysed after a short stay in the ambient, hydrogen plays a protective role against the oxidation of their surfaces. This role disappears when the stay in the ambient is so long. (author)

Preparation of LiMn2O4 cathode thin films for thin film lithium secondary batteries by a mist CVD process

International Nuclear Information System (INIS)

Tadanaga, Kiyoharu; Yamaguchi, Akihiro; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro; Duran, Alicia; Aparacio, Mario

2014-01-01

Highlights: • LiMn 2 O 4 thin films were prepared by using the mist CVD process. • An aqueous solution of lithium and manganese acetates is used for the precursor solution. • The cell with the LiMn 2 O 4 thin films exhibited a capacity of about 80 mAh/g. • The cell showed good cycling performance during 10 cycles. - Abstract: LiMn 2 O 4 cathode thin films for thin film lithium secondary batteries were prepared by using so-called the “mist CVD process”, employing an aqueous solution of lithium acetate and manganese acetate, as the source of Li and Mn, respectively. The aqueous solution of starting materials was ultrasonically atomized to form mist particles, and mists were transferred by nitrogen gas to silica glass substrate to form thin films. FE-SEM observation revealed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 750 nm were obtained. The electrochemical cell with the thin films obtained by sintering at 700 °C exhibited a capacity of about 80 mAh/g, and the cell showed good cycling performance during 10 cycles

Explosive-emission cathode fabricated using track method

International Nuclear Information System (INIS)

Akap'ev, G.N.; Korenev, S.A.

1989-01-01

Fabrication technique for large area multipoint cathodes is described. The technique is based on channels filling with metal in the ion-irradiated dielectric film producted after channel etching. It is shown, that cathode may be used under explosive emission conditions. Characteristics of diode with the mentioned type cathodes are measured

CATHODIC ELECTRODEPOSITION OF Cu 4 SnS 4 THIN FILMS FROM ACIDIC SOLUTION

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Anuar Kassim

2017-11-01

Full Text Available In this work the synthesis of copper tin sulfide thin films by electrodeposition is carried out. The films were deposited onto ITO glass substrates from an aqueous solution bath containing copper sulfate, tin chloride and sodium thiosulfate at pH 1 and room temperature. Prior to the deposition, a cyclic voltammetry experiment was carried out  between two potential limits (+1000 to -1000 mV versus Ag/AgCl to probe the effect of  the applied potential and to determine the most likely suitable electrodeposition potential  for the deposition of copper tin sulfide. The deposition was attempted at various cathodic potentials such as -400, -600, -800, -1000 mV to determine the optimum deposition  potential. The films have been characterized by techniques such as optical absorption, Xray diffraction  and  atomic  force  microscopy. The XRD patterns show that the films are polycrystalline with orthorhombic structure. The AFM studies reveal the electrodeposited films were smooth, compact and uniform at deposition potentials of –600 mV versus  Ag/AgCl. The direct optical band-gap energy was obtained to be 1.58 eV.

Annealing effect on optical properties of ZnO films fabricated by cathodic electrodeposition

International Nuclear Information System (INIS)

Wang Qingtao; Wang Guanzhong; Jie Jiansheng; Han Xinhai; Xu Bo; Hou, J.G.

2005-01-01

(001)-oriented ZnO films on Zn substrates were synthesized by cathodic electrodeposition from an aqueous solution composed only of 0.05 M zinc nitrate at 65 deg. C. A bound exciton emission band around 3.34 eV along with three longitudinal optical (LO) phonon replicas and an intensive broad emission band around 2.17 eV were observed from the photoluminescence (PL) spectra of ZnO films prepared at more positive potential (- 0.6∼- 0.8 V). When more negative potential (- 1.0∼- 1.4 V) was applied, the ultraviolet emission band disappeared. These results indicate that more positive electrodeposition potential favors the high quality ZnO film growth. The PL spectra of the annealed ZnO films prepared at more positive electrodeposition potentials - 0.6∼- 1.0 V exhibit the ultraviolet emission at 3.35 eV and a negligibly weak emission from defects. Annealing resulted in the enhancement and sharpening of the excitonic emission band and decrease of the deep level emission. The bandgap (E g ) of the ZnO film prepared at - 1.0 V on indium tin oxide (ITO) substrate decreased from 3.56 to 3.29 eV due to the removing of Zn(OH) 2 from the film after annealing

32 CFR 701.115 - Protected personal information (PPI).

Science.gov (United States)

2010-07-01

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The multilayered structure of ultrathin amorphous carbon films synthesized by filtered cathodic vacuum arc deposition

KAUST Repository

Wang, Na

2013-08-01

The structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) deposition was investigated by high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoelectron spectroscopy. Results of the plasmon excitation energy shift and through-thickness elemental concentration show a multilayered a-C film structure comprising an interface layer consisting of C, Si, and, possibly, SiC, a buffer layer with continuously increasing sp 3 fraction, a relatively thicker layer (bulk film) of constant sp 3 content, and an ultrathin surface layer rich in sp 2 hybridization. A detailed study of the C K-edge spectrum indicates that the buffer layer between the interface layer and the bulk film is due to the partial backscattering of C+ ions interacting with the heavy atoms of the silicon substrate. The results of this study provide insight into the minimum thickness of a-C films deposited by FCVA under optimum substrate bias conditions. Copyright © 2013 Materials Research Society.

Cathodic electrochemical deposition of Magnéli phases TinO2n−1 thin films at different temperatures in acetonitrile solution

International Nuclear Information System (INIS)

Ertekin, Zeliha; Tamer, Uğur; Pekmez, Kadir

2015-01-01

Highlights: • TiO x films were prepared by cathodic electrodeposition in acetonitrile. • One-step electrodeposition of TiO x films without heat treatment process. • Different crystalline Ti n O 2n−1 films (γTi 3 O 5 , λTi 3 O 5 , Ti 4 O 7 , Ti 5 O 9 ) were obtained. - Abstract: The Magnéli phase titanium oxide films prepared by cathodic electrodeposition on indium–tin-oxide coated glass substrates from saturated peroxo-titanium solution in acetonitrile. Electrodeposited brownish semi-conductor thin films were identified via X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy (SEM). The effects of different potentials and temperatures on the crystallinity of the thin films have been discussed. Ti 3 O 5 , Ti 4 O 7 and Ti 5 O 9 as the most favorable forms of the Ti n O 2n−1 were electrodeposited on ITO electrode at electrochemical deposition potentials and different temperatures. The present investigation reveals that the electrochemical deposition of crystalline Ti n O 2n−1 films by a simple one-step electrodeposition method (without any heat treatment) in acetonitrile solution is possible and very promising as a preparation method for electrochemical applications

In situ polymerization process of polypyrrole ultrathin films

International Nuclear Information System (INIS)

Onoda, Mitsuyoshi; Tada, Kazuya; Shinkuma, Akira

2006-01-01

A novel thin film processing technique has been developed for the fabrication of ultrathin films of conducting polymers with molecular-level control over thickness and multilayer architecture. This new self-assembly process opens up vast possibilities in applications which require large area, ultrathin films of conducting polymers and more importantly in applications that can take advantage of the unique interactions achievable in the complex, supermolecular architectures of multilayer films. In in situ polymerized polypyrrole (PPy), the deposition process strongly depends on the nature of the substrate surface. That is, for a surface that is negatively charged, there is a linear correspondence between dipping time and the amount of PPy deposited on the substrate. However, in the case of a positively charged surface, there is an apparent rest period of approximately 10-20 min, during which no PPy is deposited. From optical absorption spectroscopy and photoelectron emission studies etc., it became clear that oligomers of pyrrole were adsorbed on the positively charged surface during the rest period, as a result the polymerization reaction of PPy could proceed

Anomalous transmission through heavily doped conducting polymer films with periodic subwavelength hole array

Science.gov (United States)

Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

2006-08-01

We observed resonantly enhanced (or anomalous transmission) terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF 6 molecules [PPy(PF6)]. The anomalous transmission spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the resonantly enhanced transmission peaks are broader in the exotic metallic PPy(PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, indicating that the surface plasmon polaritons on the PPy(PF6) film surfaces have higher attenuation.

High-Current Cold Cathode Employing Diamond and Related Materials

Energy Technology Data Exchange (ETDEWEB)

Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

2014-10-22

The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

A solid state actuator based on polypyrrole (PPy) and a solid electrolyte NBR working in air

Science.gov (United States)

Cho, Misuk; Nam, Jaedo; Choi, Hyouk Ryeol; Koo, Jachoon; Lee, Youngkwan

2005-05-01

The solid polymer electrolyte based conducting polymer actuator was presented. In the preparation of acutuator module, an ionic liquid impregnated a synthetic rubber (NBR) and PPy were used as a solid polymer electrolyte and conducting polymer, respectively. An ionic liquid, 1-butyl-3-methylimidazolium bis (trifluoromethyl sulfonyl)imide (BMITFSI) is gradually dispersed into the NBR film and the conducting polymer, PPy was synthesized on the surface of NBR. The ionic conductivity of new type solid polymer electrolyte as a function of the immersion time was investigated. The cyclic voltammetry responsed and the redox switching dynamics of PEDOT in NBR matrix were studied. The displacement of the actuator was measured by laser beam.

Development of thin film cathodes for lithium-ion batteries in the material system Li–Mn–O by r.f. magnetron sputtering

International Nuclear Information System (INIS)

Fischer, J.; Adelhelm, C.; Bergfeldt, T.; Chang, K.; Ziebert, C.; Leiste, H.; Stüber, M.; Ulrich, S.; Music, D.; Hallstedt, B.; Seifert, H.J.

2013-01-01

Today most commercially available lithium ion batteries are still based on the toxic and expensive LiCoO 2 as a standard cathode material. However, lithium manganese based cathode materials are cheaper and environmentally friendlier. In this work cubic-LiMn 2 O 4 spinel, monoclinic-Li 2 MnO 3 and orthorhombic-LiMnO 2 thin films have been synthesized by non-reactive r.f. magnetron sputtering from two ceramic targets (LiMn 2 O 4 , LiMnO 2 ) in a pure argon discharge. The deposition parameters, namely target power and working gas pressure, were optimized in a combination with a post deposition heat treatment with respect to microstructure and electrochemical behavior. The chemical composition was determined using inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The films' crystal structure, phase evolution and morphology were investigated by X-ray diffraction, micro Raman spectroscopy and scanning electron microscopy. Due to the fact that these thin films consist of the pure active material without any impurities, such as binders or conductive additives like carbon black, they are particularly well suited for measurements of the intrinsic physical properties, which is essential for fundamental understanding. The electrochemical behavior of the cubic and the orthorhombic films was investigated by galvanostatic cycling in half cells against metallic lithium. The cubic spinel films exhibit a maximum specific capacity of ∼ 82 mAh/g, while a specific capacity of nearly 150 mAh/g can be reached for the orthorhombic counterparts. These films are promising candidates for future all solid state battery applications. - Highlights: ► Synthesis of 3 Li–Mn–O structures by one up-scalable thin film deposition method ► Formation of o-LiMnO 2 by r.f. magnetron sputtering in combination with post-annealing ► Discharge capacity with o-LiMnO 2 cathodes twice as high as for c-LiMn 2 O 4 ► Thin film deposition of m-Li 2 MnO 3 and

Review of US Nanocorp - SNL Joint Development of Thermal-Sprayed Thin-Film Cathodes for Thermal Batteries

Energy Technology Data Exchange (ETDEWEB)

GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.; DAI,JINXIANG; XIAO,T. DANNY; REISNER,DAVID E.

2000-11-14

The use of plasma spray to deposit thin metal-sulfide cathode films is described in this paper. Conventional electroactive stack components in thermal batteries are constructed from pressed-powder parts that are difficult to fabricate in large diameters in thicknesses <0.010. Plasma-sprayed electrodes do not steer from this difficulty, allowing greater energy densities and specific energies to be realized. Various co-spraying agents have been found suitable for improving the mechanical as well as electrochemical properties of plasma-sprayed cathodes for thermal batteries. These electrodes generally show equal or improved performance over conventional pressed-powder electrodes. A number of areas for future growth and development of plasma-spray technology is discussed.

Crystallography and Growth of Epitaxial Oxide Films for Fundamental Studies of Cathode Materials Used in Advanced Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Leonid A. Bendersky

2017-05-01

Full Text Available Li-ion battery systems, synthesized as epitaxial thin films, can provide powerful insights into their electrochemical processes. Crystallographic analysis shows that many important cathode oxides have an underlying similarity: their structures can be considered as different ordering schemes of Li and transition metal ions within a pseudo-cubic sublattice of oxygen anions arranged in a face-center cubic (FCC fashion. This oxygen sublattice is compatible with SrTiO3 and similar perovskite oxides, thus perovskites can be used as supporting substrates for growing epitaxial cathode films. The predicted epitaxial growth and crystallographic relations were experimentally verified for different oxide films deposited by pulsed laser deposition (PLD on SrTiO3 or SrRuO3/SrTiO3 of different orientations. The results based on cross-sectional high-resolution TEM of the following films are presented in the paper: (a trigonal LiCoO2; (b orthorhombic LiMnO2; (c monoclinic Li2MnO3; (d compositionally-complex monoclinic Li1.2Mn0.55Ni0.15Co0.1O2. All results demonstrated the feasibility of epitaxial growth for these materials, with the growth following the predicted cube-on-cube orientation relationship between the cubic and pseudo-cubic oxygen sublattices of a substrate and a film, respectively.

Osteoblast Adhesion on Cathodic Arc Plasma Deposited Nano-Multilayered TiCrAlSiN Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Kyu [University of Ulsan, Ulsan (Korea, Republic of); Pham, Vuong Hung [Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2014-03-15

Adhesion of osteoblast cells to TiCrAlSiN thin films was evaluated in vitro. Ti and TiCrAlSiN thin films were deposited on glass substrates by cathodic arc deposition. Surface roughness and chemistry of the TiCrAlSiN thin films was characterized by AFM and EPMA, respectively. Ti and TiCrAlSiN thin films and glass coverslips were cultured with human osteoblast cells (hFOB 1.19). The cell cytoskeleton was analyzed by observing the organization of actin stress fibers and microtubules. Cell proliferation was investigated by MTT assay and visualization. Focal contact adhesion was studied by observing the vinculin density. The results indicated that the TiCrAlSiN coating significantly influenced the actin cytoskeleton and microtubule organization. Human osteoblasts hFOB attached and proliferated better on TiCrAlSiN thin films with more focal contact adhesions than on Ti thin films or glass surfaces. These results suggest that TiCrAlSiN thin films can be an implantable material where the maximum cell adhesion is required.

Cesium-incorporated indium-tin-oxide films for use as a cathode with low work function for a transparent organic light-emitting device

International Nuclear Information System (INIS)

Uchida, Takayuki; Mimura, Toshifumi; Ohtsuka, Masao; Otomo, Toshio; Ide, Mieko; Shida, Azusa; Sawada, Yutaka

2006-01-01

Transparent organic light-emitting devices (TOLEDs) were successfully fabricated utilizing a novel transparent conducting cathode with low work function. Cesium-incorporated indium-tin-oxide film was deposited on the organic layers with negligible damage by simultaneous operation of RF magnetron sputtering using an ITO target and vacuum evaporation of metallic cesium. Incorporation of cesium in the ITO film was confirmed by XPS analysis. The work function (4.3 eV) determined by photoelectron spectroscopy in air (PESA) was lower than that of 0.3-0.4-eV without cesium-incorporation and stable under the atmospheric environment. The electron injection efficiency of cesium-incorporated ITO cathode in the present transparent OLED fabricated was comparable to that of the previous double-layered structure comprising of ITO cathode and an organic buffer layer (BCP) doped by evaporation of cesium [T. Uchida, S. Kaneta, M. Ichihara, M. Ohtsuka, T. Otomo, D.R. Marx, Jpn. J. Appl. Phys., 44, No. 9 (2005) L282

Improving the conductance of ZnO thin film doping with Ti by using a cathodic vacuum arc deposition process

International Nuclear Information System (INIS)

Wu, Chun-Sen; Lin, Bor-Tsuen; Jean, Ming-Der

2011-01-01

The Ti-doped ZnO films compared to un-doped ZnO films were deposited onto Corning XG glass substrates by using a cathodic vacuum arc deposition process in a mixture of oxygen and argon gases. The structural, electrical and optical properties of un-doped and Ti-doped ZnO films have been investigated. When the Ti target power is about 750 W, the incorporation of titanium atoms into zinc oxide films is obviously effective. Additionally, the resistivity of un-doped ZnO films is high and reduces to a value of 3.48 x 10 -3 Ω-cm when Ti is incorporated. The Ti doped in the ZnO films gave rise to the improvement of the conductivity of the films obviously. The Ti-doped ZnO films have > 85% transmittance in a range of 400-700 nm.

Construction of tubular polypyrrole-wrapped biomass-derived carbon nanospheres as cathode materials for lithium–sulfur batteries

International Nuclear Information System (INIS)

Yu, Qiuhong; Lu, Yang; Peng, Tao; Hou, Xiaoyi; Luo, Rongjie; Wang, Yange; Yan, Hailong; Luo, Yongsong; Liu, Xianming; Kim, Jang-Kyo

2017-01-01

A promising hybrid material composed of tubular polypyrrole (T-PPy)-wrapped monodisperse biomass-derived carbon nanospheres (BCSs) was first synthesized successfully via a simple hydrothermal approach by using watermelon juice as the carbon source, and further used as an anchoring object for sulfur (S) of lithium–sulfur (Li–S) batteries. The use of BCSs with hydrophilic nature as a framework could provide large interface areas between the active materials and electrolyte, and improve the dispersion of T-PPy, which could help in the active material utilization. As a result, BCS@T-PPy/S as a cathode material exhibited a high capacity of 1143.6 mA h g −1 and delivered a stable capacity up to 685.8 mA h g −1 after 500 cycles at 0.5 C, demonstrating its promising application for rechargeable Li–S batteries. (paper)

Fabrication and Protein Conjugation of Aligned Polypyrrole-Poly(L-lactic acid) Fibers Film with the Conductivity and Stability.

Science.gov (United States)

Qin, Jiabang; Huang, Zhongbing; Yin, Guangfu; Yang, Anneng; Han, Wei

2016-03-01

The conducting composite scaffold, including fiber-cores of aligned poly(L-lactic acid) (PLLA) and shell-layer of polypyrrole (PPy), was fabricated, and then bovine serum albumin (BSA) was conjugated on the PPy shell-layer. Aligned PLLA fibers (about 300 nm diameter) were obtained by electrospinning and rotating drum collection, and then coated by PPy nanoparticles (NPs, about 50 nm diameter) via chemical oxidation. The surface resistivity of PPy-PLLA fibers film were 0.971, 0.874 kΩ. cm at the fiber's vertical and parallel directions, respectively. The results of PPy-PLLA fibers film immersed in phosphate buffer saline for 8 d indicated that the fibers morphology and the film conductivity were not significantly changed, and the fluorescent images showed that FITC-labeled BSA (FITC-BSA) were successfully conjugated in the fibers film with carbodiimide chemistry, and the largest amount of FITC-BSA conjugated in the fibers film from 100 μg/mL proteins solution was 31.31 μg/cm2 due to lots of poly(glutamic acid) in surface-nanogrooves of the fibers surface. Under electrical stimulation of 100 mV, the fibers film was accompanied the release of all conjugated FITC-BSA with the detachment of some PPy NPs. These results suggested that PPy-PLLA fibers film would be potentially applied in the construction of degradable tissue engineering scaffold with protein factors, especially neurotrophic factors for nerve tissue repair.

One-step electrochemical composite polymerization of polypyrrole integrated with functionalized graphene/carbon nanotubes nanostructured composite film for electrochemical capacitors

International Nuclear Information System (INIS)

Ding Bing; Lu Xiangjun; Yuan Changzhou; Yang Sudong; Han Yongqin; Zhang Xiaogang; Che Qian

2012-01-01

Graphical abstract: A novel one-step electrochemical co-deposition strategy was first proposed to prepare unique polypyrrole/reduced graphene oxide/carbon nanotubes (PPy/F-RGO/CNTs) ternary composites, where F-RGO, CNTs, and PPy were electrodeposited simultaneously to construct a three-dimensional (3-D) highly porous film electrode. Highlights: ► Isolated, water-soluble graphene was obtained through benzenesulfonic functionalization. ► PPy/F-RGO/CNTs ternary composite film was prepared via one-step electrochemical co-deposition route. ► PPy/F-RGO/CNTs film shows 3-D highly porous nanostructure and high electrical conductivity. ► PPy/F-RGO/CNTs film exhibits high capacitance, good high-rate performance with a remarkable cycling stability. - Abstract: A novel one-step electrochemical composite polymerization strategy was first proposed to prepare unique polypyrrole/reduced graphene oxide/carbon nanotubes (PPy/F-RGO/CNTs) ternary composites, where F-RGO, CNTs, and PPy were electrodeposited simultaneously to construct a three-dimensional (3-D) highly porous film electrode. Such ternary composite film electrode exhibits a high specific capacitance of 300 F g −1 at 1 A g −1 as well as a remarkable cycling stability at high rates, which is related to its unique nanostructure and high electrical conductivity. F-RGO and CNTs act as an electron-transporting backbone of a 3-D porous nanostructure, leaving adequate working space for facile electrolyte penetration and better faradaic utilization of the electro-active PPy. Furthermore, the straightforward approach proposed here can be readily extended to prepare other composite film electrodes with good electrochemical performance for energy storage.

Conductance measurement by two-line probe method of polypyrrole nano-films formed on mica by admicellar polymerization

Energy Technology Data Exchange (ETDEWEB)

Mou, C.-Y. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Yuan, W.-L. [Department of Chemical Engineering, Feng Chia University, Taichung 40724, Taiwan (China)], E-mail: wyuan@fcu.edu.tw; Tsai, I-S. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); O' Rear, Edgar A. [School of Chemical, Biological and Material Engineering, University of Oklahoma, Norman, OK 73019 (United States); Barraza, Harry [Unilever R and D HPC, Quarry Road East, Bebington, Wirral, CH63 3JW (United Kingdom)

2008-10-01

Measuring the electrical conductance is of importance in fabricating electronic devices based on semiconducting thin films. In this report, electrically conducting polypyrrole (PPy) nano-films were deposited on insulating mica plates by admicellar polymerization. It becomes difficult to measure such film conductance in the lateral direction due the nanometric thickness which only allows for very low electrical current. In order to understand the effects of surfactant on the film conductivity, morphological studies using atomic force microscopy and conductance measurements with a sub-fA multimeter were performed. Higher conductances were found for PPy thin films made using surfactant templates, than that of a bare mica surface. Using the two-line probe method by drawing two lines of silver glue 8 mm apart on the sample surface, the current-voltage curves of bare mica surface yielded a lateral conductance of 6.0 x 10{sup -13} S. In comparison, PPy thin films made using sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) as surfactant templates showed conductances of 1.2 x 10{sup -11} S and 7.7 x 10{sup -12} S, respectively. The higher conductances indicate tunneling, hopping, and percolation of charge carriers throughout the films. The lower-bound conductivities were calculated as 4.0 x 10{sup -3} S/cm and 2.6 x 10{sup -3} S/cm, measured based on the average thickness 2.3 nm for the SDS-PPy films and 2.4 nm for the CTAB-PPy films. Conductivities for both SDS and CTAB template PPy films are found to be of the same order.

Conductance measurement by two-line probe method of polypyrrole nano-films formed on mica by admicellar polymerization

International Nuclear Information System (INIS)

Mou, C.-Y.; Yuan, W.-L.; Tsai, I-S.; O'Rear, Edgar A.; Barraza, Harry

2008-01-01

Measuring the electrical conductance is of importance in fabricating electronic devices based on semiconducting thin films. In this report, electrically conducting polypyrrole (PPy) nano-films were deposited on insulating mica plates by admicellar polymerization. It becomes difficult to measure such film conductance in the lateral direction due the nanometric thickness which only allows for very low electrical current. In order to understand the effects of surfactant on the film conductivity, morphological studies using atomic force microscopy and conductance measurements with a sub-fA multimeter were performed. Higher conductances were found for PPy thin films made using surfactant templates, than that of a bare mica surface. Using the two-line probe method by drawing two lines of silver glue 8 mm apart on the sample surface, the current-voltage curves of bare mica surface yielded a lateral conductance of 6.0 x 10 -13 S. In comparison, PPy thin films made using sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) as surfactant templates showed conductances of 1.2 x 10 -11 S and 7.7 x 10 -12 S, respectively. The higher conductances indicate tunneling, hopping, and percolation of charge carriers throughout the films. The lower-bound conductivities were calculated as 4.0 x 10 -3 S/cm and 2.6 x 10 -3 S/cm, measured based on the average thickness 2.3 nm for the SDS-PPy films and 2.4 nm for the CTAB-PPy films. Conductivities for both SDS and CTAB template PPy films are found to be of the same order

Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

International Nuclear Information System (INIS)

Panwar, O.S.; Khan, Mohd. Alim; Kumar, Mahesh; Shivaprasad, S.M.; Satyanarayana, B.S.; Dixit, P.N.; Bhattacharyya, R.; Khan, M.Y.

2008-01-01

The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp 3 bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp 3 content and sp 3 /sp 2 ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp 3 (80%) bonding and sp 3 /sp 2 (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp 3 (87-91%) bonding and sp 3 /sp 2 (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications

Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

Energy Technology Data Exchange (ETDEWEB)

Panwar, O.S. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India)], E-mail: ospanwar@mail.nplindia.ernet.in; Khan, Mohd. Alim [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Kumar, Mahesh; Shivaprasad, S.M. [Surface Physics and Nanostructures Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Satyanarayana, B.S. [MIT Innovation Centre and Electronics and Communication Department, Manipal Institute of Technology, Manipal-579104 (India); Dixit, P.N. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Bhattacharyya, R. [Emeritus Scientist, National Physical Laboratory, New Delhi-110012 (India); Khan, M.Y. [Department of Physics, Jamia Millia Islamia, Central University, New Delhi-110025 (India)

2008-02-29

The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp{sup 3} bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp{sup 3} content and sp{sup 3}/sp{sup 2} ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp{sup 3} (80%) bonding and sp{sup 3}/sp{sup 2} (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp{sup 3} (87-91%) bonding and sp{sup 3}/sp{sup 2} (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications.

Comparison of analytical possibilities of inversion voltammetry of tellurium with cathodic and anodic potential scanning taking layer-by-layer analysis of GaAs-Te films as example

International Nuclear Information System (INIS)

Kaplin, A.A.; Portnyagina, Eh.O.; Gridaev, V.F.

1979-01-01

Possibility of application in analytical purposes of the process of tellurium precipitation electrosolution from the surfaces of graphite and mercury-graphite electrodes at the cathode scanning of the potential is shown. As a result of comparison of direct and inversion scanning with cathodic and anodic scanning of the potential, variants of voltammetric method of tellurium determination in artificial solutions and, taking the developed method of layer-by-layer analysis of the GaAsTe films as an example, advantage of mercury-graphite electrode with cathodic scanning as compared to graphite electrode with cathode scanning of the potential is shown. Reproducibility of the GaAs film analysis results according to anodic and cathodic tellurium peaks is satisfactory. Maximum deviation from the results of analysis of oxidation peaks and tellurium peduction does not exceed 15 rel. %. Thus, for tellurium concentrations, exceeding 5x10 -6 g-ion/l, both anodic and cathodic scanning of the potential can be used, though error in tellurium determination according to cathodic peaks is 1.5-2.0 times higher. At tellurium amounts lower 5x10 -6 g-ion/l the determination should be carried out according to the peaks of tellurium anodic oxidation from the surface of graphite electrode or according to the peaks of tellurium cathodic reduction from the surface of mercury-graphite electrode

The preparation and characterization of CNx film with high nitrogen content by cathode electrodeposition

International Nuclear Information System (INIS)

Zhang, J.-T.; Cao, C.-B.; Lv Qiang; Li Chao; Zhu Hesun

2003-01-01

CN x thin film with high nitrogen content was prepared on ITO conductive glass substrates by cathode electrodeposition, using dicyandiamide (C 2 H 4 N 4 ) in acetone as precursors. The surface morphologies, atomic bonding state, and chemical composition were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. The CN x particles got nanometer level with the average size of 80 nm. The maximum value of the N/C atomic ratio was more than 1. Carbon and nitrogen existed mainly in the form of tetrahedral C-N bonds, with a few C-N bonds. From UV-Vis absorption spectrum, we found that during near-ultraviolet area the deposited CN x films appeared nonlinear optical absorption phenomena, and the ultraviolet light (200-280 nm) could be transmitted. The electrical resistivities of the films were in the range of 10 12 -10 16 Ω cm

Fabrication of high conductivity dual multi-porous poly (L-lactic acid)/polypyrrole composite micro/nanofiber film

International Nuclear Information System (INIS)

Yu Qiaozhen; Dai Zhengwei; Lan Ping

2011-01-01

Highlights: → PLLA/H 2 SO 4 -doped PPy composite micro/nano fibers dual multi-pore membranes with high conductivity were fabricated by combining electrospinning with in situ polymerization.These composite fibers have a core-shell structure, the PPy is the core and the PLLA/PPy is the shell. → The size and shape of the pores in this PPy composite fiber membrane can be tuned by polymerization parameters. The largest size of the pores is about 250 μm. → The conductivity of this composite fiber membrane can be adjusted by polymerization parameters. The highest conductivity is 179.0 S cm -1 . The PLLA fibers act as the template in the pyrrole polymerization process and contributed to the increase of the conductivity. - Abstract: Dual multi-porous PLLA (poly(L-lactic acid))/H 2 SO 4 -doped PPy (polypyrrole) composite micro/nano fiber films were fabricated by combining electrospinning with in situ polymerization. The morphologies and structures of the resulting samples were analyzed by scanning electron microscopy (SEM). It was found that the composite micro/nano fibers exhibited a core-shell structure and the composite fiber film had a dual multi-pore structure composed of pores both in the fibers and among the fibers. Semiconductor parameter analyzer was used to characterize the electrical properties of the samples. It was interesting to find that all the PLLA/H 2 SO 4 -doped PPy composite micro/nano fiber films had higher conductivity than H 2 SO 4 -doped PPy particles when the polymerization time up to 180 min. Effects of the pyrrole synthesis conditions on the pore size and the conductivity of PLLA/PPy composite fiber film were assessed. By optimizing the polymerization conditions, the max conductivity of this composite fiber film was about 179.0 S cm -1 with a pore size of about 250 μm. The possible mechanism of PLLA/H 2 SO 4 -doped PPy composite micro/nano fiber films had much higher conductivity than H 2 SO 4 -doped PPy particles was discussed.

Experimental and ab initio investigations on textured Li–Mn–O spinel thin film cathodes

Energy Technology Data Exchange (ETDEWEB)

Fischer, J., E-mail: Julian.Fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Music, D. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 52074 Aachen (Germany); Bergfeldt, T.; Ziebert, C.; Ulrich, S.; Seifert, H.J. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2014-12-01

This paper describes the tailored preparation of nearly identical lithium–manganese–oxide thin film cathodes with different global grain orientations. The thin films were synthesized by rf magnetron sputtering from a LiMn{sub 2}O{sub 4}-target in a pure argon plasma. Under appropriate processing conditions, thin films with a cubic spinel structure and a nearly similar density and surface topography but different grain orientation, i.e. (111)- and (440)-textured films, were achieved. The chemical composition was determined by inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The constitution- and microstructure were evaluated by X-ray diffraction and Raman spectroscopy. The surface morphology and roughness were investigated by scanning electron and atomic force microscopy. The differently textured films represent an ideal model system for studying potential effects of grain orientation on the lithium ion diffusion and electrochemical behavior in LiMn{sub 2}O{sub 4}-based thin films. They are nearly identical in their chemical composition, atomic bonding behavior, surface-roughness, morphology and thickness. Our initial ab initio molecular dynamics data indicate that Li ion transport is faster in (111)-textured structure than in (440)-textured one. - Highlights: • Thin film model system of differently textured cubic Li–Mn–O spinels. • Investigation of the Li–Mn–O thin film mass density by X-ray reflectivity. • Ab initio molecular dynamics simulation on Li ion diffusion in LiMn{sub 2}O{sub 4}.

Experimental and ab initio investigations on textured Li–Mn–O spinel thin film cathodes

International Nuclear Information System (INIS)

Fischer, J.; Music, D.; Bergfeldt, T.; Ziebert, C.; Ulrich, S.; Seifert, H.J.

2014-01-01

This paper describes the tailored preparation of nearly identical lithium–manganese–oxide thin film cathodes with different global grain orientations. The thin films were synthesized by rf magnetron sputtering from a LiMn 2 O 4 -target in a pure argon plasma. Under appropriate processing conditions, thin films with a cubic spinel structure and a nearly similar density and surface topography but different grain orientation, i.e. (111)- and (440)-textured films, were achieved. The chemical composition was determined by inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The constitution- and microstructure were evaluated by X-ray diffraction and Raman spectroscopy. The surface morphology and roughness were investigated by scanning electron and atomic force microscopy. The differently textured films represent an ideal model system for studying potential effects of grain orientation on the lithium ion diffusion and electrochemical behavior in LiMn 2 O 4 -based thin films. They are nearly identical in their chemical composition, atomic bonding behavior, surface-roughness, morphology and thickness. Our initial ab initio molecular dynamics data indicate that Li ion transport is faster in (111)-textured structure than in (440)-textured one. - Highlights: • Thin film model system of differently textured cubic Li–Mn–O spinels. • Investigation of the Li–Mn–O thin film mass density by X-ray reflectivity. • Ab initio molecular dynamics simulation on Li ion diffusion in LiMn 2 O 4

Status of PPI (Pohang Photo-Injector) for PAL XFEL

CERN Document Server

Park, Sung-Ju; Oh, Jong-Seok; Park, Chong-Do; Park Jang Ho; Soo Ko In; Wang, Xijie; Woon Parc, Yong

2005-01-01

A X-Ray Free Electron Laser (XFEL) project based on the Self-Amplified Spontaneous Emission (SASE) is under progress at the Pohang Accelerator Laboratory (PAL). One of the critical R&D for the PAL XFEL* is to develop the Pohang Photo-Injector (PPI) which is required to deliver electron beams with normalized emittance < 1.5 mm-mrad. In order to achieve the required beam quality with high stability and reliability, we will use photocathode with quantum efficiency > 0.1 % and long lifetime. This will greatly lessen the laser energy requirement for producing flat-top UV pulses, and open the possibility of using only regenerative amplifiers (RGAs) to drive the photocathode RF gun. The RGAs can produce mJs output with much better stability than multi-pass amplifiers. Both the Cs2Te and Mg are under consideration for the possible photo-cathode. To demonstrate the suitability of the Mg and Cs2Te for the future 4th generation light source application, an improved BNL-type S-band RF gun with a high-pe...

Preparation and characterization of visible light-driven AgCl/PPy photocatalyst

International Nuclear Information System (INIS)

Gu Shuna; Li Bing; Zhao Chongjun; Xu Yunlong; Qian Xiuzhen; Chen, Guorong

2011-01-01

Graphical abstract: AgCl/PPy composite exhibits improved photocatalytic performance and high stability under visible light. Display Omitted Highlights: → AgCl/(PPy) nanocomposites as visible light driven photocatalyst. → Composites exhibited high visible light-driven photocatalytic activity and stability. → Photocatalytic process on MO followed photoreduction mechanisms. → Used photocatalyst can be regenerated in aqueous FeCl 3 solution. - Abstract: Visible light photoactive AgCl/polypyrrole (PPy) composites were prepared via the reaction between excessive Ag + and Cl - ions in the presence of PPy . The AgCl/PPy composites were systematically characterized using Fourier transform infrared (FTIR) spectroscopy, Raman spectra, X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Thermal gravity analysis (TGA). It was found that face-centered cubic AgCl nanocrystallite and 0.2 wt% PPy component existed in the composite and spherical AgCl/PPy nanoparticles were in the range of 200-600 nm. The AgCl/PPy composites showed higher visible light-driven photocatalytic activity and stability than that of AgCl. A photoreduction mechanism was postulated for AgCl/PPy photocatalyst on dye methyl orange (MO). The used AgCl/PPy photocatalyst was facilely regenerated by an oxidation process in aqueous FeCl 3 solution.

Preparation and characterization of visible light-driven AgCl/PPy photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Gu Shuna; Li Bing [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao Chongjun, E-mail: chongjunzhao@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xu Yunlong; Qian Xiuzhen; Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2011-05-05

Graphical abstract: AgCl/PPy composite exhibits improved photocatalytic performance and high stability under visible light. Display Omitted Highlights: > AgCl/(PPy) nanocomposites as visible light driven photocatalyst. > Composites exhibited high visible light-driven photocatalytic activity and stability. > Photocatalytic process on MO followed photoreduction mechanisms. > Used photocatalyst can be regenerated in aqueous FeCl{sub 3} solution. - Abstract: Visible light photoactive AgCl/polypyrrole (PPy) composites were prepared via the reaction between excessive Ag{sup +} and Cl{sup -} ions in the presence of PPy{sub .} The AgCl/PPy composites were systematically characterized using Fourier transform infrared (FTIR) spectroscopy, Raman spectra, X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Thermal gravity analysis (TGA). It was found that face-centered cubic AgCl nanocrystallite and 0.2 wt% PPy component existed in the composite and spherical AgCl/PPy nanoparticles were in the range of 200-600 nm. The AgCl/PPy composites showed higher visible light-driven photocatalytic activity and stability than that of AgCl. A photoreduction mechanism was postulated for AgCl/PPy photocatalyst on dye methyl orange (MO). The used AgCl/PPy photocatalyst was facilely regenerated by an oxidation process in aqueous FeCl{sub 3} solution.

Resonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer films

Science.gov (United States)

Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

2006-02-01

We observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The "anomalous transmission" spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the `anomalous transmission' peaks are broader in the exotic metallic PPy (PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, showing that the surface plasmon polaritons on the PPy (PF6) film surfaces have higher attenuation.

Development of thin film cathodes for lithium-ion batteries in the material system Li–Mn–O by r.f. magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Fischer, J., E-mail: julian.fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Adelhelm, C.; Bergfeldt, T. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Chang, K. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 46 52074 Aachen (Germany); Ziebert, C.; Leiste, H.; Stüber, M.; Ulrich, S. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Music, D.; Hallstedt, B. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 46 52074 Aachen (Germany); Seifert, H.J. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2013-01-01

Today most commercially available lithium ion batteries are still based on the toxic and expensive LiCoO{sub 2} as a standard cathode material. However, lithium manganese based cathode materials are cheaper and environmentally friendlier. In this work cubic-LiMn{sub 2}O{sub 4} spinel, monoclinic-Li{sub 2}MnO{sub 3} and orthorhombic-LiMnO{sub 2} thin films have been synthesized by non-reactive r.f. magnetron sputtering from two ceramic targets (LiMn{sub 2}O{sub 4}, LiMnO{sub 2}) in a pure argon discharge. The deposition parameters, namely target power and working gas pressure, were optimized in a combination with a post deposition heat treatment with respect to microstructure and electrochemical behavior. The chemical composition was determined using inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The films' crystal structure, phase evolution and morphology were investigated by X-ray diffraction, micro Raman spectroscopy and scanning electron microscopy. Due to the fact that these thin films consist of the pure active material without any impurities, such as binders or conductive additives like carbon black, they are particularly well suited for measurements of the intrinsic physical properties, which is essential for fundamental understanding. The electrochemical behavior of the cubic and the orthorhombic films was investigated by galvanostatic cycling in half cells against metallic lithium. The cubic spinel films exhibit a maximum specific capacity of ∼ 82 mAh/g, while a specific capacity of nearly 150 mAh/g can be reached for the orthorhombic counterparts. These films are promising candidates for future all solid state battery applications. - Highlights: ► Synthesis of 3 Li–Mn–O structures by one up-scalable thin film deposition method ► Formation of o-LiMnO{sub 2} by r.f. magnetron sputtering in combination with post-annealing ► Discharge capacity with o-LiMnO{sub 2} cathodes twice as high as for c

Investigation of polypyrrole/polyvinyl alcohol–titanium dioxide composite films for photo-catalytic applications

Energy Technology Data Exchange (ETDEWEB)

Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long, E-mail: jianglong@scu.edu.cn; Dan, Yi, E-mail: danyichenweiwei@163.com

2015-07-01

Graphical abstract: - Highlights: • The study provides an easy and convenient method to fabricate films, which will give guidance for the preparation of three-dimensional materials. • The PPy/PVA–TiO{sub 2} films can keep better photo-catalytic activities both under UV and visible light irradiation when compared with TiO{sub 2} film. • There exist electron transfers between PPy/PVA and TiO{sub 2}. - Abstract: Polypyrrole/polyvinyl alcohol–titanium dioxide (PPy/PVA–TiO{sub 2}) composite films used as photo-catalysts were fabricated by combining TiO{sub 2} sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO{sub 2} and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet–vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA–TiO{sub 2} composite films show better photo-catalytic properties than TiO{sub 2} film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA–TiO{sub 2} composite film was investigated and the results show that

Sulfur X-ray absorption fine structure in porous Li–S cathode films measured under argon atmospheric conditions

International Nuclear Information System (INIS)

Müller, Matthias; Choudhury, Soumyadip; Gruber, Katharina; Cruz, Valene B.; Fuchsbichler, Bernd; Jacob, Timo; Koller, Stefan; Stamm, Manfred; Ionov, Leonid; Beckhoff, Burkhard

2014-01-01

In this paper we present the first results for the characterization of highly porous cathode materials with pore sizes below 1 μm for Lithium Sulfur (Li–S) batteries by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. A novel cathode material of porous carbon films fabricated with colloidal array templates has been investigated. In addition, an electrochemical characterization has been performed aiming on an improved correlation of physical and chemical parameters with the electrochemical performance. The performed NEXAFS measurements of cathode materials allowed for a chemical speciation of the sulfur content inside the cathode material. The aim of the presented investigation was to evaluate the potential of the NEXAFS technique to characterize sulfur in novel battery material. The long term goal for the characterization of the battery materials is the sensitive identification of undesired side reactions, such as the polysulfide shuttle, which takes place during charging and discharging of the battery. The main drawback associated with the investigation of these materials is the fact that NEXAFS measurements can usually only be performed ex situ due to the limited in situ instrumentation being available. For Li–S batteries this problem is more pronounced because of the low photon energies needed to study the sulfur K absorption edge at 2472 eV. We employed 1 μm thick Si 3 N 4 windows to construct sealed argon cells for NEXAFS measurements under ultra high vacuum (UHV) conditions as a first step towards in situ measurements. The cells keep the sample under argon atmosphere at any time and the X-ray beam passes mainly through vacuum which enables the detection of the low energy X-ray emission of sulfur. Using these argon cells we found indications for the presence of lithium polysulfides in the cathode films whereas the correlations to the offline electrochemical results remain somewhat ambiguous. As a consequence of these findings one may

Effect of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} powder addition in the precursor solution on the properties of cathode films deposited by spray pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Silva, Caio Luis Santos; Rangel, Maria do Carmo, E-mail: clssilva@ufba.br, E-mail: mcarmov@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Grupo de Estudo em Cinetica e Catalise; Gama, Leonardo Marques; Paes Junior, Herval Ramos, E-mail: leonardo.m.gama@gmail.com, E-mail: herval@uenf.br [Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ (Brazil). Laboratorio de Materiais Avancados; Santos, Jacqueline Amanda Figueiredo dos; Domingues, Rosana Zacarias, E-mail: jac.amanda28@gmail.com, E-mail: rosanazd@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Laboratorio de Materiais e Pilhas a Combustivel

2017-01-15

Films of lanthanum strontium manganite, LSM (La{sub 0.8}Sr{sub 0.2}MnO{sub 3}) were deposited on yttria stabilized zirconia (YSZ) substrates by different methods aiming to establish the most suitable route to prepare cathodes for solid oxide fuel cells (SOFC). Samples were obtained by using a solution of lanthanum, strontium and manganese nitrates or a dispersion of the LSM powder in this solution. Both commercial and synthesized LSM powders were used, the last one obtained by amorphous citrate method. The films were deposited by spray pyrolysis on YSZ substrates prepared by uniaxial and isostatic pressing. Samples were characterized by scanning electron microscopy, confocal laser scanning microscopy, X-ray diffraction and two-probe conductivity measurements. The area specific resistance and relaxation to cathodic activation were measured by electrochemical impedance spectroscopy. The substrate obtained by uniaxial pressing and the commercial LSM produced films with the highest amount of surface cracks. The film obtained from the suspension showed area specific resistance and activation energy lower than the other produced from the solution. For both samples, the cathodic activation process resulted in an initial reduction of the total resistance of around 20%, the sample produced from the suspension being more resistant to relaxation. Therefore, the LSM suspension is more suitable than the salts solution for preparing films by spray pyrolysis on YSZ substrates to obtain efficient cathodes for SOFC. (author)

Flexible Overoxidized Polypyrrole Films with Orderly Structure as High-Performance Anodes for Li- and Na-Ion Batteries.

Science.gov (United States)

Yuan, Tao; Ruan, Jiafeng; Zhang, Weimin; Tan, Zhuopeng; Yang, Junhe; Ma, Zi-Feng; Zheng, Shiyou

2016-12-28

Flexible polypyrrole (PPy) films with highly ordered structures were fabricated by a novel vapor phase polymerization (VPP) process and used as the anode material in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The PPy films demonstrate excellent rate performance and cycling stability. At a charge/discharge rate of 1 C, the reversible capacities of the PPy film anode reach 284.9 and 177.4 mAh g -1 in LIBs and SIBs, respectively. Even at a charge/discharge rate of 20 C, the reversible capacity of the PPy film anode retains 54.0% and 52.9% of the capacity of 1 C in LIBs and SIBs, respectively. After 1000 electrochemical cycles at a rate of 10 C, there is no obvious capacity fading. The molecular structure and electrochemical behaviors of Li- and Na-ion doping and dedoping in the PPy films are investigated by XPS and ex situ XRD. It is believed that the PPy film electrodes in the overoxidized state can be reversibly charged and discharged through the doping and dedoping of lithium or sodium ions. Because of the self-adaptation of the doped ions, the ordered pyrrolic chain structure can realize a fast charge/discharge process. This result may substantially contribute to the progress of research into flexible polymer electrodes in various types of batteries.

Preparation of LiMn{sub 2}O{sub 4} cathode thin films for thin film lithium secondary batteries by a mist CVD process

Energy Technology Data Exchange (ETDEWEB)

Tadanaga, Kiyoharu, E-mail: tadanaga@chem.osakafu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531 (Japan); Yamaguchi, Akihiro; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531 (Japan); Duran, Alicia; Aparacio, Mario [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas, Kelsen 5 (Campus de Cantoblanco), Madrid, 28049 (Spain)

2014-05-01

Highlights: • LiMn{sub 2}O{sub 4} thin films were prepared by using the mist CVD process. • An aqueous solution of lithium and manganese acetates is used for the precursor solution. • The cell with the LiMn{sub 2}O{sub 4} thin films exhibited a capacity of about 80 mAh/g. • The cell showed good cycling performance during 10 cycles. - Abstract: LiMn{sub 2}O{sub 4} cathode thin films for thin film lithium secondary batteries were prepared by using so-called the “mist CVD process”, employing an aqueous solution of lithium acetate and manganese acetate, as the source of Li and Mn, respectively. The aqueous solution of starting materials was ultrasonically atomized to form mist particles, and mists were transferred by nitrogen gas to silica glass substrate to form thin films. FE-SEM observation revealed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 750 nm were obtained. The electrochemical cell with the thin films obtained by sintering at 700 °C exhibited a capacity of about 80 mAh/g, and the cell showed good cycling performance during 10 cycles.

Synthesis of Ti-doped DLC film on SS304 steels by Filtered Cathodic Vacuum Arc (FCVA) technique for tribological improvement

Science.gov (United States)

Bootkul, D.; Saenphinit, N.; Supsermpol, B.; Aramwit, C.; Intarasiri, S.

2014-08-01

Currently, stainless steels are widely used in various industrial applications due to their excellence in toughness and corrosion resistance. But their resistance to wear needs to be improved for appropriate use in tribological applications. The Filtered Cathodic Vacuum Arc (FCVA) is a superior technique for forming a high-density film structure of amorphous carbon, especially for a tetrahedral amorphous carbon (ta-C) type, because it can produce a plasma of highly energetic ions that can penetrate into a growing coating, resulting in densification of the film. However, this technique tends to generate high internal stress, due to serious accumulation of energy in the film structure that then leads to film delamination. In general, there are numerous solutions that have been used to reduce the internal stress. DLC with various additive elements such as Ti, Cr or W as strong-carbide-forming (SCF) metals is one of the popular methods to provide attractive combinations of properties of wear resistance and film adhesion as well as reducing the internal stress. The present study was focused on investigation of titanium-doped DLC coating on SS304 steel, mainly for adhesion improvement in optimizing for tribological applications. The synthesized films were formed by the FCVA technique at normal substrate temperature. In the experimental set-up, the films were produced by mixing the titanium and carbon ions generated by dual cathode plasma source operating in synchronous pulsed mode. Their compositions were adjusted by varying the relative duration of the pulse length from each cathode. Titanium doping concentration was varied from pure DLC deposition as the control group to titanium and graphite trigger pulses ratios of 1:16, 1:12, 1:10, 1:8 and 1:4, as the Ti-doped DLC group. The results showed that by increasing titanium trigger pulses ratio from 1:16, 1:12, 1:10 and 1:8, respectively, the film adhesion was increased while the wear rate did not change significantly as

Superhard nanocomposite nc-TiC/a-C:H film fabricated by filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Wang Yaohui; Zhang Xu; Wu Xianying; Zhang Huixing; Zhang Xiaoji

2008-01-01

Superhard nanocomposite nc-TiC/a-C:H films, with an excellent combination of high elastic recovery, low friction coefficient and good H/E ratio, were prepared by filtered cathodic vacuum arc technique using the C 2 H 2 gas as the precursor. The effect of C 2 H 2 flow rate on the microstructure, phase composition, mechanical and tribological properties of nanocomposite nc-TiC/a-C:H films have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse spectroscopy (EDS), microindentation and tribotester measurements. It was observed that the C 2 H 2 flow rate significantly affected the Ti content and hardness of films. Furthermore, by selecting the proper value for C 2 H 2 flow rate, 20 sccm, one can deposit the nanocomposite film nc-TiC/a-C:H with excellent properties such as superhardness (66.4 GPa), high elastic recovery (83.3%) and high H/E ratio (0.13)

Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

Directory of Open Access Journals (Sweden)

Andréa Santos Liu

2007-06-01

Full Text Available Polypyrrole (PPy films were galvanostatically deposited on 99.9 wt. (% aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments.

RADAR PPI Scope Overlay

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — RADAR PPI Scope Overlays are used to position a RADAR image over a station at the correct resolution. The archive maintains several different RADAR resolution types,...

The effect of substrate bias on titanium carbide/amorphous carbon nanocomposite films deposited by filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Zhang, Xu; Liang, Hong; Wu, Zhenglong; Wu, Xiangying; Zhang, Huixing

2013-01-01

The titanium carbide/amorphous carbon nanocomposite films have been deposited on silicon substrate by filtered cathodic vacuum arc (FCVA) technology, the effects of substrate bias on composition, structures and mechanical properties of the films are studied by scanning electron spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy and nano-indentation. The results show that the Ti content, deposition rate and hardness at first increase and then decrease with increasing the substrate bias. Maximum hardness of the titanium carbide/amorphous carbon nanocomposite film is 51 Gpa prepared at −400 V. The hardness enhancement may be attributed to the compressive stress and the fraction of crystalline TiC phase due to ion bombardment

Hybrid thin films based on bilayer heterojunction of titania nanocrystals/polypyrrole/natural dyes (Kappaphycus alvarezii) materials

Science.gov (United States)

Ghazali, Salmah Mohd; Salleh, Hasiah; Dagang, Ahmad Nazri; Ghazali, Mohd Sabri Mohd; Ali, Nik Aziz Nik; Rashid, Norlaily Abdul; Kamarulzaman, Nurul Huda; Ahmad, Wan Almaz Dhafina Che Wan

2017-09-01

In this research, hybrid thin films which consist of a combination of organic red seaweed (RS) (Kappaphycus alvarezii) and polypyrrole (PPy) with inorganic titania nanocrystals (TiO2 NCs) materials were fabricated. These hybrid thin films were fabricated accordingly with bilayer heterojunction of ITO/TiO2 NCs/PPy/RS via electrochemical method using Electrochemical Impedance Spectroscopy (EIS). The effect of number of scans (thickness) of titania on optical and electrical properties of hybrid thin films were studied. TiO2 NCs function as an electron acceptor and electronic conductor. Meanwhile, PPy acts as holes conductor and RS dye acts as a photosensitizer enhances the optical and electrical properties of the thin films. The UV absorption spectrum of TiO2 NCs, PPy and RS are characterized by UV-Visible spectroscopy, while the functional group of RS was characterized by Fourier transform infrared spectroscopy (FTIR). The UV-Vis spectra showed that TiO2 NCs, PPy and RS were absorbed over a wide range of light spectrum which were 200-300 nm, 300-900 nm and 250-900 nm; respectively. The FTIR spectra of the RS showed the presence of hydroxyl group which was responsible for a good sensitizer for these hybrid solar cells. The electrical conductivity of these hybrid thin films were measured by using four point probes. The electrical conductivity of ITO/ (1)TiO2 NCs/PPy/RS thin film under the radiation of 100 Wm-2 was 0.062 Scm-1, hence this hybrid thin films can be applied in solar cell application.

Ion Movement in Polypyrrole/Dodecylbenzenesulphonate Films in aqueous and non-aqueous electrolytes

DEFF Research Database (Denmark)

Vidanapathirana, K.; Careem, M.A.; Skaarup, Steen

2002-01-01

The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements. Investigati......The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements....... Investigations were carried out using aqueous and non-aqueous electrolytes to study the effect of solvent on the ion movement during redox processes. When PPy films are cycled in aqueous electrolytes transport of both anion and cation occurs during oxidation and reduction. However, when cycled in the nonaqueous...

Influences of arc current on composition and properties of MgO thin films prepared by cathodic vacuum arc deposition

International Nuclear Information System (INIS)

Zhu Daoyun; Zheng Changxi; Wang Mingdong; Liu Yi; Chen Dihu; He Zhenhui; Wen Lishi; Cheung, W.Y.

2010-01-01

MgO thin films with high optical transmittances (more than 90%) were prepared by cathodic vacuum arc deposition technique. With the increase of arc current from 40 to 80 A, the deposition pressure decreases and the film thickness increases; the atomic ratio of Mg/O in MgO thin films (obtained by RBS) increases from 0.97 to 1.17, giving that deposited at 50 A most close to the stoichiometric composition of the bulk MgO; the grains of MgO thin films grow gradually as shown in SEM images. XRD patterns show that MgO (1 1 0) orientation is predominant for films prepared at the arc currents ranged from 50 to 70 A. The MgO (1 0 0) orientation is much enhanced and comparable to that of MgO (1 1 0) for films prepared at the arc current of 80 A. The secondary electron emission coefficient of MgO thin film increases with arc current ranged from 50 to 70 A.

Effects of filtered cathodic vacuum arc deposition (FCVAD) conditions on photovoltaic TiO{sub 2} films

Energy Technology Data Exchange (ETDEWEB)

Aramwit, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Intarasiri, S. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Bootkul, D. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Supsermpol, B.; Seanphinit, N. [Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Western Digital Thailand Co. Ltd., Ayutthaya 13160 (Thailand); Ruangkul, W. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2014-08-15

Highlights: • Titanium dioxide films were synthesized using the FCVAD technique. • Various FCVAD conditions were tested. • The TiO{sub 2} films were characterized. • The FCVAD condition effects on the film characteristics were studied. • The O{sub 2} pressure had the most important effect on the film quality. - Abstract: Titanium dioxide (TiO{sub 2}) films for photovoltaic applications were synthesized using filtered cathodic vacuum arc deposition (FCVAD) technique. Various deposition conditions were tested for an optimal film formation. The conditions included the oxygen (O{sub 2}) pressure which was varied from a base pressure 10{sup −5} to 10{sup −4}, 10{sup −3}, 10{sup −2} and 10{sup −1} Torr, sample holder bias varied using 0 or −250 V, deposition time varied from 10, 20 to 30 min, and deposition distance varied from 1 to 3 cm. The deposited films were also annealed and compared with unannealed ones. The films under various conditions were characterized using optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS) and Raman spectroscopy techniques. The film transparency increased and thickness decreased to a nanoscale with increasing of the O{sub 2} pressure. The transparent deposited films contained stoichiometric titanium and oxygen under the medium O{sub 2} pressure. The as-deposited films were TiO{sub 2} containing some rutile but no anatase which needed annealing to form.

The Roll of NaPSS Surfactant on the Ceria Nanoparticles Embedding in Polypyrrole Films

Directory of Open Access Journals (Sweden)

Simona Popescu

2016-01-01

Full Text Available Cerium oxide nanoparticles (CeO2 NPs in crystalline form have been synthesized by a coprecipitation method. CeO2 nanoparticles were then embedded in polypyrrole (PPy films during the electropolymerization of pyrrole (Py on titanium substrate. The influence of poly(sodium 4-styrenesulfonate (NaPSS surfactant used during polymerization on the embedding of CeO2 NPs in polypyrrole films was investigated. The new films were characterized in terms of surface analysis, wettability, electrochemical behaviour, and antibacterial effect. The surface and electrochemical characterization revealed the role of surfactant on PPy doping process cerium oxide incorporation. In the presence of surfactant, CeO2 NPs are preferentially embedded in the polymeric film while, without surfactant, the ceria nanoparticles are quasiuniformly spread as agglomerates onto polymeric films. The antibacterial effect of studied PPy films was substantially improved in the presence of cerium oxide and depends by the polymerization conditions.

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

International Nuclear Information System (INIS)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping; Sun, Zhaoqi; Lv, Jianguo

2014-01-01

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO 3 − ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo, E-mail: lvjg1@163.com [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China)

2014-12-05

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO{sub 3}{sup −} ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology.

Reducing DRIFT backgrounds with a submicron aluminized-mylar cathode

Science.gov (United States)

Battat, J. B. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Lumnah, A.; Matthews, J.; Miller, E. H.; Mouton, F.; Murphy, A. St. J.; Paling, S. M.; Phan, N.; Sadler, S. W.; Scarff, A.; Schuckman, F. G.; Snowden-Ifft, D.; Spooner, N. J. C.; Walker, D.

2015-09-01

Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 μm thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within 10%. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of 3.3±0.1 ppt 234U and 73±2 ppb 238U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of 70±20 compared to the original stainless steel wire cathode. First results are presented from a texturized version of the cathode, intended to be even more transparent to alpha particles. These efforts, along with other background reduction measures, have resulted in a drop in the observed background rate from 500/day to 1/day. With the recent implementation of full-volume fiducialization, these remaining background events are identified, allowing for background-free operation.

Characterization of Lanthanum Ferric Cobaltite doped with Strontium (LSCF) films deposited by spray-pyrolysis for application as cathode in PaCOS-TI; Caracterizacao de filmes de CFLE depositados por spray-pirolise para utilizacao como catodo em PaCOS-TI

Energy Technology Data Exchange (ETDEWEB)

Almeida, L.S.; Guimaraes, V.F.; Paes Junior, H.R. [Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados], Emails: laryssadsa@yahoo.com.br, valtencyguimaraes@yahoo.com.br, herval@uenf.br

2010-07-01

The lanthanum ferric cobaltite doped with strontium (LSCF) is a ceramic material with the perovskite structure that stands out in the field of research for its use as cathode in solid oxide fuel cells at intermediate temperatures (IT-SOFC). The films were synthesized by spray-pyrolysis technique on 8% mol Yttria stabilized zirconia (YSZ) substrates. It was studied the influence of heat treatment temperatures (600-1000 deg C) on the properties of the films under the conditions of treatment during four hours. Samples were tested electrically by measuring the variation of electrical conductivity with temperature, structurally by X-ray diffraction (XRD) and morphologically by scanning electron microscopy (SEM). The films heat treated at 700 deg C for 4 hours showed better performance for application as cathode. (author)

Synthesis and microwave absorption properties of PPy/Co nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Luo, Juhua, E-mail: luojuhua@163.com [School of Materials Engineering, Yancheng Institute of Technology, Yancheng 224051 (China); Gao, Duoduo [School of Material Science and Engineering, Changzhou University, Changzhou 213164 (China)

2014-11-15

Polypyrrole (PPy)/cobalt (Co) nanocomposites were successfully prepared by an in-situ polymerization of pyrrole in the presence of synthesized Co nanoparticles. Characterization of the product was accomplished by XRD, TEM, FT-IR, VSM, and vector network analyzer techniques. XRD analysis revealed that characteristic diffraction peaks of polypyrrole and Co appeared at the same time in nanocomposites. FT-IR analysis indicated a successful conjugation of Co particles with polypyrrole. TEM confirmed the formation of a core-shell structure with a wide particle size distribution. Magnetization measurements showed that polypyrrole coating decreased the saturation magnetization of Co significantly. With the increase of the matching thickness, the absorption peak varied towards low frequency direction. When the matching thickness was 3.0 mm, the value of the maximum reflection loss (RL) was −20.0 dB at 13.8 GHz with the 7.2 GHz bandwidth. - Highlights: • The influence of PPy on the structure of Co is discussed. • The influence of PPy on the magnetic properties of Co is discussed. • The influence of PPy on the absorption property of Co is discussed. • PPy/Co possessed the excellent absorption property.

Polypyrrole/carbon nanotube nanocomposite enhanced the electrochemical capacitance of flexible graphene film for supercapacitors

Science.gov (United States)

Lu, Xiangjun; Dou, Hui; Yuan, Changzhou; Yang, Sudong; Hao, Liang; Zhang, Fang; Shen, Laifa; Zhang, Luojiang; Zhang, Xiaogang

2012-01-01

The flexible electrodes have important potential applications in energy storage of portable electronic devices for their powerful structural properties. In this work, unique flexible films with polypyrrole/carbon nanotube (PPy/CNT) composite homogeneously distributed between graphene (GN) sheets are successfully prepared by flow-assembly of the mixture dispersion of GN and PPy/CNT. In such layered structure, the coaxial PPy/CNT nanocables can not only enlarge the space between GN sheets but also provide pseudo-capacitance to enhance the total capacitance of electrodes. According to the galvanostatic charge/discharge analysis, the mass and volume specific capacitances of GN-PPy/CNT (52 wt% PPy/CNT) are 211 F g-1 and 122 F cm-3 at a current density of 0.2 A g-1, higher than those of the GN film (73 F g-1 and 79 F cm-3) and PPy/CNT (164 F g-1 and 67 F cm-3). Significantly, the GN-PPy/CNT electrode shows excellent cycling stability (5% capacity loss after 5000 cycles) due to the flexible GN layer and the rigid CNT core synergistical releasing the intrinsic differential strain of PPy chains during long-term charge/discharge cycles.

Deposition and characterization of thin films of materials with application in cathodes for lithium rechargeable micro batteries

International Nuclear Information System (INIS)

Lopez I, J.

2007-01-01

In this thesis work is reported the deposition and characterization of thin films of materials of the type LiMO 2 , with M=Co and Ni, which have application in cathodes for micro-batteries of lithium ions. In the last years some investigators have reported that the electrochemical operation of the lithium ions batteries it can improve recovering the cathode, in bundle form, with some metal oxides as the Al 2 O 3 ; for that the study of the formation of thin films in bilayer form LiMO 2 /AI 2 O 3 is of interest in the development of lithium ions micro batteries. The thin films were deposited using the laser ablation technique studying the effect of some deposit parameters in the properties of the one formed material, as: laser fluence, substrate temperature and working atmosphere, with the purpose of optimizing it. In the case of the LiCoO 2 it was found that to use an inert atmosphere of argon allows to obtain the material with the correct composition. Additionally, with the use of a temperature in the substrate of 150 C is possible to obtain to the material with certain crystallinity grade that to the subjected being to a post-deposit thermal treatment at 300 C for three hours, it gives as result a totally crystalline material. In the case of the thin films of LiNiO 2 , it was necessary to synthesize the oxide starting from a reaction of solid state among nickel oxide (NiO) and lithium oxide (Li 2 O) obtaining stoichiometric LiNiO 2 . For the formation of the thin films of LiNiO 2 it was used an argon atmosphere and the laser fluence was varied, the deposits were carried out to two different substrates temperatures, atmosphere and 160 C. In both cases the material it was recovered with an alumina layer, found that this layer didn't modify the structural properties of the base oxide (LiCoO 2 and LiNiO 2 ). (Author)

Chemically designed Pt/PPy nano-composite for effective LPG gas sensor.

Science.gov (United States)

Gaikwad, Namrata; Bhanoth, Sreenu; More, Priyesh V; Jain, G H; Khanna, P K

2014-03-07

Simultaneous in situ reduction of hexachloroplatinic acid by the amine group in the pyrrole monomer and oxidation of pyrrole to form polypyrrole (PPy) was examined. The reactions were performed at various temperatures to understand the degree of reduction of platinum precursor as well as doping of polypyrrole with Pt(II) chloro-complex. Spectroscopic images revealed different morphologies for the Pt/PPy nano-composite prepared at various temperatures. The as-prepared Pt/PPy nano-composite samples were tested for their ability to sense liquefied petroleum gas (LPG) which resulted in excellent sensing at relatively low temperature. The porous nature and ohmic contact between the PPy and platinum nanoparticles makes the as-prepared Pt/PPy nano-composite highly useful for sensors as well as electronic applications.

Low-temperature liquid phase deposited TiO{sub 2} films on stainless steel for photogenerated cathodic protection applications

Energy Technology Data Exchange (ETDEWEB)

Lei, C.X.; Zhou, H. [College of Materials, Xiamen University, Xiamen 361005 (China); Feng, Z.D., E-mail: zdfeng@xmu.edu.cn [College of Materials, Xiamen University, Xiamen 361005 (China); Zhu, Y.F.; Du, R.G. [College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China)

2011-06-01

The low-temperature synthesis of anatase TiO{sub 2} films was an imperative requirement for their application to corrosion prevention of metals. In this paper, a liquid phase deposition (LPD) technique was developed to prepare TiO{sub 2} films on SUS304 stainless steel (304SS) at a relatively low temperature (80 deg. C). The as-prepared films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photon spectroscopy (XPS). It was observed that a dense and crack-free anatase TiO{sub 2} film with a thickness about 300 nm was obtained. The film contained some fluorine and nitrogen elements, and the amounts of these impurities were greatly decreased upon calcination. Under the white light illumination, the electrode potential of TiO{sub 2} coated 304SS rapidly shifted to a more negative direction. Moreover, the photopotential of TiO{sub 2}/304SS electrode showed more negative values with increased film thickness. In conclusion, the photogenerated cathodic protection of 304SS was achieved by the low-temperature LPD-derived TiO{sub 2} film.

Sensitivity of PPI analysis to differences in noise reduction strategies.

Science.gov (United States)

Barton, M; Marecek, R; Rektor, I; Filip, P; Janousova, E; Mikl, M

2015-09-30

In some fields of fMRI data analysis, using correct methods for dealing with noise is crucial for achieving meaningful results. This paper provides a quantitative assessment of the effects of different preprocessing and noise filtering strategies on psychophysiological interactions (PPI) methods for analyzing fMRI data where noise management has not yet been established. Both real and simulated fMRI data were used to assess these effects. Four regions of interest (ROIs) were chosen for the PPI analysis on the basis of their engagement during two tasks. PPI analysis was performed for 32 different preprocessing and analysis settings, which included data filtering with RETROICOR or no such filtering; different filtering of the ROI "seed" signal with a nuisance data-driven time series; and the involvement of these data-driven time series in the subsequent PPI GLM analysis. The extent of the statistically significant results was quantified at the group level using simple descriptive statistics. Simulated data were generated to assess statistical improvement of different filtering strategies. We observed that different approaches for dealing with noise in PPI analysis yield differing results in real data. In simulated data, we found RETROICOR, seed signal filtering and the addition of data-driven covariates to the PPI design matrix significantly improves results. We recommend the use of RETROICOR, and data-driven filtering of the whole data, or alternatively, seed signal filtering with data-driven signals and the addition of data-driven covariates to the PPI design matrix. Copyright © 2015 Elsevier B.V. All rights reserved.

Crystalline structure and microstructural characteristics of the cathode/electrolyte solid oxide half-cells

International Nuclear Information System (INIS)

Chiba, Rubens; Vargas, Reinaldo Azevedo; Andreoli, Marco; Santoro, Thais Aranha de Barros; Seo, Emilia Satoshi Miyamaru

2009-01-01

The solid oxide fuel cell (SOFC) is an electrochemical device generating of electric energy, constituted of cathode, electrolyte and anode; that together they form a unity cell. The study of the solid oxide half-cells consisting of cathode and electrolyte it is very important, in way that is the responsible interface for the reduction reaction of the oxygen. These half-cells are ceramic materials constituted of strontium-doped lanthanum manganite (LSM) for the cathode and yttria-stabilized zirconia (YSZ) for the electrolyte. In this work, two solid oxide half-cells have been manufactured, one constituted of LSM cathode thin film on YSZ electrolyte substrate (LSM - YSZ half-cell), and another constituted of LSM cathode and LSM/YSZ composite cathode thin films on YSZ electrolyte substrate (LSM - LSM/YSZ - YSZ half cell). The cathode/electrolyte solid oxide half-cells were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results have been presented with good adherence between cathode and electrolyte and, LSM and YSZ phases were identified. (author)

Cold cathode emission studies on topographically modified few layer and single layer MoS2 films

Science.gov (United States)

Gaur, Anand P. S.; Sahoo, Satyaprakash; Mendoza, Frank; Rivera, Adriana M.; Kumar, Mohit; Dash, Saroj P.; Morell, Gerardo; Katiyar, Ram S.

2016-01-01

Nanostructured materials, such as carbon nanotubes, are excellent cold cathode emitters. Here, we report comparative field emission (FE) studies on topographically tailored few layer MoS2 films consisting of ⟨0001⟩ plane perpendicular (⊥) to c-axis (i.e., edge terminated vertically aligned) along with planar few layer and monolayer (1L) MoS2 films. FE measurements exhibited lower turn-on field Eto (defined as required applied electric field to emit current density of 10 μA/cm2) ˜4.5 V/μm and higher current density ˜1 mA/cm2, for edge terminated vertically aligned (ETVA) MoS2 films. However, Eto magnitude for planar few layer and 1L MoS2 films increased further to 5.7 and 11 V/μm, respectively, with one order decrease in emission current density. The observed differences in emission behavior, particularly for ETVA MoS2 is attributed to the high value of geometrical field enhancement factor (β), found to be ˜1064, resulting from the large confinement of localized electric field at edge exposed nanograins. Emission behavior of planar few layers and 1L MoS2 films are explained under a two step emission mechanism. Our studies suggest that with further tailoring the microstructure of ultra thin ETVA MoS2 films would result in elegant FE properties.

[Study on the land use optimization based on PPI].

Science.gov (United States)

Wu, Xiao-Feng; Li, Ting

2012-03-01

Land use type and managing method which is greatly influenced by human activities, is one of the most important factors of non-point pollution. Based on the collection and analysis of non-point pollution control methods and the concept of the three ecological fronts, 9 land use optimized scenarios were designed according to rationality analysis of the current land use situation in the 3 typed small watersheds in Miyun reservoir basin. Take Caojialu watershed for example to analyze and compare the influence to environment of different scenarios based on potential pollution index (PPI) and river section potential pollution index (R-PPI) and the best combination scenario was found. Land use scenario designing and comparison on basis of PPI and R-PPI could help to find the best combination scenario of land use type and managing method, to optimize space distribution and managing methods of land use in basin, to reduce soil erosion and to provide powerful support to formulation of land use planning and pollution control project.

Oxadiazole-carbazole polymer (POC)-Ir(ppy)3 tunable emitting composites

Science.gov (United States)

Bruno, Annalisa; Borriello, Carmela; Di Luccio, Tiziana; Sessa, Lucia; Concilio, Simona; Haque, Saif A.; Minarini, Carla

2017-04-01

POC polymer is an oxadiazole-carbazole copolymer we have previously synthetized and established as light emitting material in Organic Light Emitting Devices (OLEDs), although POC quantum yield emission efficiency and color purity still need to be enhanced. On the other hand, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) complexes, namely Ir(ppy)3 are among the brightest luminophores employed in green light emitting devices. Our aim, in this work, is to take advantage of Ir(ppy)3 bright emission by combining the Ir complex with blue emitting POC to obtain tunable light emitting composites over a wide range of the visible spectrum. Here we have investigated the optical proprieties POC based nanocomposites with different concentrations of Ir(ppy)3, ranging from 1 to 10 wt%. Both spectral and time resolved fluorescence measurements show an efficient energy transfer from the polymer to the dopants, resulting in white-emitting composites. The most intense and stable emission has been found when POC was doped with about 5 wt% concentration of Ir(ppy)3.

A comparative study on electrochemical co-deposition and capacitance of composite films of conducting polymers and carbon nanotubes

International Nuclear Information System (INIS)

Peng Chuang; Jin Jun; Chen, George Z.

2007-01-01

Composite films of carbon nanotubes (CNTs) with polyaniline (PANI), polypyrrole (PPY) or poly[3,4-ethylenedioxythiophene] (PEDOT) were prepared via electrochemical co-deposition from solutions containing acid treated CNTs and the corresponding monomer. In the cases of PPY and PEDOT, CNTs served as the charge carriers during electro-deposition, and also acted as both the backbone of a three-dimensional micro- and nano-porous structure and the effective charge-balancing dopant within the polymer. All the composites showed improved mechanical integrity, higher electronic and ionic conductivity (even when the polymer was reduced), and exhibited larger electrode specific capacitance than the polymer alone. Under similar conditions, the capacitance was enhanced significantly in as-prepared PPY-CNT and PEDOT-CNT films. However, the fresh PANI-CNT film was electrochemically similar to PANI, but PPY-CNT and PEDOT-CNT differed noticeably from the respective polymers alone. In continuous potential cycling tests, unlike the pure polymer and other composite films, PANI-CNT performed much better in retaining the capacitance of the as-prepared film, and the possible cause is analysed

Physical and electrochemical properties of ZnO films fabricated from highly cathodic electrodeposition potentials

Science.gov (United States)

Ismail, Abdul Hadi; Abdullah, Abdul Halim; Sulaiman, Yusran

2017-03-01

The physical and electrochemical properties of zinc oxide (ZnO) film electrode that were prepared electrochemically were studied. ZnO was electrodeposited on ITO glass substrate by applying three different highly cathodic potentials (-1.3 V, -1.5 V, -1.7 V) in a solution containing 70 mM of Zn(NO3)2.xH2O and 0.1 M KCl with bath temperatures of 70 °C and 80 °C. The presence of ZnO was asserted from XRD analysis where the corresponding peaks in the spectra were assigned. SEM images revealed the plate-like hexagonal morphology of ZnO which is in agreement with the XRD analysis. The areal capacitance of the ZnO was observed to increase when the applied electrodeposition potential is increased from -1.3 V to -1.5 V. However, the areal capacitance is found to decrease when the applied electrodeposition potential is further increased to -1.7 V. The resistance of charge transfer (Rct) of the ZnO decreased when the applied electrodeposition potential varies from -1.3 V to -1.7 V due to the decreased particle size of ZnO when more cathodic electrodeposition potential is applied.

FMFinder: A Functional Module Detector for PPI Networks

Directory of Open Access Journals (Sweden)

M. Modi

2017-10-01

Full Text Available Bioinformatics is an integrated area of data mining, statistics and computational biology. Protein-Protein Interaction (PPI network is the most important biological process in living beings. In this network a protein module interacts with another module and so on, forming a large network of proteins. The same set of proteins which takes part in the organic courses of biological actions is detected through the Function Module Detection method. Clustering process when applied in PPI networks is made of proteins which are part of a larger communication network. As a result of this, we can define the limits for module detection as well as clarify the construction of a PPI network. For understating the bio-mechanism of various living beings, a detailed study of FMFinder detection by clustering process is called for.

Changes of electrochemical properties of polypyrrole when synthesized in a room-temperature ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Dalmolin, Carla, E-mail: carla.dalmolin@udesc.br; Biaggio, Sonia R.; Bocchi, Nerilso; Rocha-Filho, Romeu C.

2014-09-15

The room-temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate, BMIM BF{sub 4}, was employed as electrolyte in the electrosynthesis of thin polypyrrole (PPy) films on a Pt substrate, and the resulting PPy electrodes were electrochemically characterized. Electrochemical impedance spectroscopy (EIS) was used to comparatively investigate the electric behavior of PPy produced in the RTIL and the one produced in a traditional acetonitrile/lithium salt system, and charge–discharge curves in the range 2.0–4.0 V (vs. Li/Li{sup +}) were obtained in a 1.0 M LiBF{sub 4} propylene carbonate solution. Although a reduction of the specific capacity for the PPy obtained in the RTIL was observed, compared to that of the PPy film synthesized in the acetonitrilic electrolyte, its chronopotentiometric profile presented a plateau in the 2.7 V region. This is a remarkable result, considering that a linear decrease in this profile is usually observed for the majority of conducting polymer cathodes. PPy films obtained in BMIM BF{sub 4} presented globular morphology, with a special arrangement of nanoparticles constituting the globules; the EIS results indicated that this nanoscale structure may be contributing to a better definition of the redox characteristics during the PPy charge–discharge processes, as it happens for the well-organized structure of some metal oxides. - Highlights: • PPy was produced in an ionic liquid medium as active material for battery electrodes. • Discharge curves present a plateau not usual for conducting polymer electrodes. • RTIL used as synthesis electrolyte produced PPy with surface nanograins. • Morphological features explain the improved redox properties of PPy electrode. • Electrical properties of PPy grown in RTIL were accessed by impedance measurements.

Structural, nanomechanical and variable range hopping conduction behavior of nanocrystalline carbon thin films deposited by the ambient environment assisted filtered cathodic jet carbon arc technique

Energy Technology Data Exchange (ETDEWEB)

Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Rawal, Ishpal; Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Kumar, Mahesh [Ultrafast Opto-Electronics and Tetrahertz Photonics Group, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India)

2015-04-15

Highlights: • Nanocrystalline carbon thin films are grown by filtered cathodic jet carbon arc process. • Effect of gaseous environment on the properties of carbon films has been studied. • The structural and nanomechanical properties of carbon thin films have been studied. • The VRH conduction behavior in nanocrystalline carbon thin films has been studied. - Abstract: This paper reports the deposition and characterization of nanocrystalline carbon thin films by filtered cathodic jet carbon arc technique assisted with three different gaseous environments of helium, nitrogen and hydrogen. All the films are nanocrystalline in nature as observed from the high resolution transmission electron microscopic (HRTEM) measurements, which suggests that the nanocrystallites of size ∼10–50 nm are embedded though out the amorphous matrix. X-ray photoelectron spectroscopic studies suggest that the film deposited under the nitrogen gaseous environment has the highest sp{sup 3}/sp{sup 2} ratio accompanied with the highest hardness of ∼18.34 GPa observed from the nanoindentation technique. The film deposited under the helium gaseous environment has the highest ratio of the area under the Raman D peak to G peak (A{sub D}/A{sub G}) and the highest conductivity (∼2.23 S/cm) at room temperature, whereas, the film deposited under the hydrogen environment has the lowest conductivity value (2.27 × 10{sup −7} S/cm). The temperature dependent dc conduction behavior of all the nanocrystalline carbon thin films has been analyzed in the light of Mott’s variable range hopping (VRH) conduction mechanism and observed that all the films obey three dimension VRH conduction mechanism for the charge transport.

Plasma distribution of cathodic ARC deposition system

International Nuclear Information System (INIS)

Anders, S.; Raoux, S.; Krishnan, K.; MacGill, R.A.; Brown, I.G.

1996-01-01

The plasma distribution using a cathodic arc plasma source with and without magnetic macroparticle filter has been determined by depositing on a transparent plastic substrate and measuring the film absorption. It was found that the width of the distribution depends on the arc current, and it also depends on the cathode material which leads to a spatial separation of the elements when an alloy cathode is used. By applying a magnetic multicusp field near the exit of the magnetic filter, it was possible to modify the plasma distribution and obtain a flat plasma profile with a constant and homogeneous elemental distribution

Incidence Angle Effect of Energetic Carbon Ions on Deposition Rate, Topography, and Structure of Ultrathin Amorphous Carbon Films Deposited by Filtered Cathodic Vacuum Arc

KAUST Repository

Wang, N.; Komvopoulos, K.

2012-01-01

The effect of the incidence angle of energetic carbon ions on the thickness, topography, and structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) was examined in the context of numerical

Does the Sustainable PPI Investments Promote Financial Market’s Sustainable Development?

Directory of Open Access Journals (Sweden)

Tong Fu

2016-01-01

Full Text Available Since the late 1980s, most developing countries adopt a policy of attracting investments for Private Participation in Infrastructure (PPI projects. With a perspective of sustainability, this paper offers a first attempt to examine whether the sustainable PPI investments promote financial market development. First, we demonstrate how the PPI policy enlargers the size of financial markets and then fosters the liquidity of financial markets in the static and dynamic conditions. Using the data from 33 developing countries during 1997–2012, we discover the significant promotion effect of PPI investments on the development of financial markets in the dimensions of size and liquidity. Additionally, we confirm the significant mediator effect of financial market size for the positive relationship between PPI investments and financial market liquidity. Both the promotion effect and mediation effect are robust to different control variables and estimation techniques used.

SnO2/PPy Screen-Printed Multilayer CO2 Gas Sensor

Directory of Open Access Journals (Sweden)

S.A. WAGHULEY

2007-05-01

Full Text Available Tin dioxide (SnO2 plays a dominant role in solid state gas sensors and exhibit sensitivity towards oxidizing and reducing gases by a variation of its electrical properties. The electrical conducting polymer-polypyrrole (PPy has high anisotropy of electrical conduction and used as a gas sensor. SnO2/PPy multilayer, pure SnO2, pure PPy sensors were prepared by screen-printing method on Al2O3 layer followed by glass substrate. The sensors were used for different concentration (ppm of CO2 gas investigation at room temperature (303 K. The sensitivity of SnO2/PPy multilayer sensor was found to be higher, compared with pure SnO2 and pure PPy sensors. The multilayer sensor exhibited improved stability. The response and recovery time of multilayer sensor were found to be ~2 min and ~10 min respectively.

Hopping conduction on PPy/SiO2 nanocomposites obtained via in situ emulsion polymerization

NARCIS (Netherlands)

Rubinger, C.P.L.; Costa, L.C.; Carvalho Esteves, de A.C.; Barros-Timmons, A.M.M.V.

2008-01-01

This work describes the preparation and electrical characterization of conducting polypyrrole (PPy) and silica nanocomposites. Four samples were investigated: (i) pure PPy, (ii) PPy-covered SiO2 spherical nanoparticles, (iii) PPy-covered SiO2 spherical nanoparticles modified with

The Regulation of Osteogenesis Using Electroactive Polypyrrole Films

Directory of Open Access Journals (Sweden)

Chuan Li

2016-07-01

Full Text Available To evaluate the effect of electrical conductivity of biomaterials on osteogenesis, polypyrrole (PPy was fabricated by oxidative chemical polymerization as substrates for cell culture. Through adjusting the concentrations of monomer and initiator, polypyrrole films with different electrical conductivities were fabricated. These fabricated polypyrrole films are transparent enough for easy optical microscopy. Fourier transform infrared spectroscopy, X-ray spectroscopy and four-point probe were used to assess the microstructures, surface chemical compositions and electrical sheet resistance of films, respectively. Results indicate that higher monomer and initiator concentration leads to highly-branched PPy chains and thus promotes the electron mobility and electrical conductivity. Selected polypyrrole films then were applied for culturing rat bone marrow stromal cells. Cell viability and mineralization assays reveal that not only these films are biocompatible, but also capable of enhancing the calcium deposition into the extra cellular matrix by the differentiated cells.

Thin Film Microbatteries

International Nuclear Information System (INIS)

Dudney, Nancy J.

2008-01-01

Thin film batteries are built layer by layer by vapor deposition. The resulting battery is formed of parallel plates, much as an ordinary battery construction, just much thinner. The figure (Fig. 1) shows an example of a thin film battery layout where films are deposited symmetrically onto both sides of a supporting substrate. The full stack of films is only 10 to 15 (micro)m thick, but including the support at least doubles the overall battery thickness. When the support is thin, the entire battery can be flexible. At least six companies have commercialized or are very close to commercializing such all-solid-state thin film batteries and market research predicts a growing market and a variety of applications including sensors, RFID tags, and smarter cards. In principle with a large deposition system, a thin film battery might cover a square meter, but in practice, most development is targeting individual cells with active areas less than 25 cm 2 . For very small battery areas, 2 , microfabrication processes have been developed. Typically the assembled batteries have capacities from 0.1 to 5 mAh. The operation of a thin film battery is depicted in the schematic diagram (Fig. 2). Very simply, when the battery is allowed to discharge, a Li + ion migrates from the anode to the cathode film by diffusing through the solid electrolyte. When the anode and cathode reactions are reversible, as for an intercalation compound or alloy, the battery can be recharged by reversing the current. The difference in the electrochemical potential of the lithium determines the cell voltage. Most of the thin films used in current commercial variations of this thin film battery are deposited in vacuum chambers by RF and DC magnetron sputtering and by thermal evaporation onto unheated substrates. In addition, many publications report exploring a variety of other physical and chemical vapor deposition processes, such as pulsed laser deposition, electron cyclotron resonance sputtering, and

ZnO film deposition by DC magnetron sputtering: Effect of target configuration on the film properties

Energy Technology Data Exchange (ETDEWEB)

Arakelova, E.; Khachatryan, A.; Kteyan, A.; Avjyan, K.; Grigoryan, S.

2016-08-01

Ballistic transport model for target-to-substrate atom transfer during magnetron sputter deposition was used to develop zinc target (cathode) configuration that enabled growth of uniform zinc oxide films on extensive surfaces and provided reproducibility of films characteristics irrespective of the cathode wear-out. The advantage of the developed target configuration for high-quality ZnO film deposition was observed in the sputtering pressure range of 5− 50 mTorr, and in the range of cathode-to-substrate distances 7–20 cm. Characteristics of the deposited films were demonstrated by using X-ray diffraction analysis, as well as optical and electrical measurements. - Highlights: • Change of target configuration for optimization of magnetron sputtering deposition is proposed. • Improvement of ZnO film properties due to use of this target is demonstrated. • This configuration provided reproducibility of the deposited films properties.

Protein complex detection in PPI networks based on data integration and supervised learning method.

Science.gov (United States)

Yu, Feng; Yang, Zhi; Hu, Xiao; Sun, Yuan; Lin, Hong; Wang, Jian

2015-01-01

Revealing protein complexes are important for understanding principles of cellular organization and function. High-throughput experimental techniques have produced a large amount of protein interactions, which makes it possible to predict protein complexes from protein-protein interaction (PPI) networks. However, the small amount of known physical interactions may limit protein complex detection. The new PPI networks are constructed by integrating PPI datasets with the large and readily available PPI data from biomedical literature, and then the less reliable PPI between two proteins are filtered out based on semantic similarity and topological similarity of the two proteins. Finally, the supervised learning protein complex detection (SLPC), which can make full use of the information of available known complexes, is applied to detect protein complex on the new PPI networks. The experimental results of SLPC on two different categories yeast PPI networks demonstrate effectiveness of the approach: compared with the original PPI networks, the best average improvements of 4.76, 6.81 and 15.75 percentage units in the F-score, accuracy and maximum matching ratio (MMR) are achieved respectively; compared with the denoising PPI networks, the best average improvements of 3.91, 4.61 and 12.10 percentage units in the F-score, accuracy and MMR are achieved respectively; compared with ClusterONE, the start-of the-art complex detection method, on the denoising extended PPI networks, the average improvements of 26.02 and 22.40 percentage units in the F-score and MMR are achieved respectively. The experimental results show that the performances of SLPC have a large improvement through integration of new receivable PPI data from biomedical literature into original PPI networks and denoising PPI networks. In addition, our protein complexes detection method can achieve better performance than ClusterONE.

A Generalized Form of Context-Dependent Psychophysiological Interactions (gPPI): A Comparison to Standard Approaches

Science.gov (United States)

McLaren, Donald G.; Ries, Michele L.; Xu, Guofan; Johnson, Sterling C.

2012-01-01

Functional MRI (fMRI) allows one to study task-related regional responses and task-dependent connectivity analysis using psychophysiological interaction (PPI) methods. The latter affords the additional opportunity to understand how brain regions interact in a task-dependent manner. The current implementation of PPI in Statistical Parametric Mapping (SPM8) is configured primarily to assess connectivity differences between two task conditions, when in practice fMRI tasks frequently employ more than two conditions. Here we evaluate how a generalized form of context-dependent PPI (gPPI; http://www.nitrc.org/projects/gppi), which is configured to automatically accommodate more than two task conditions in the same PPI model by spanning the entire experimental space, compares to the standard implementation in SPM8. These comparisons are made using both simulations and an empirical dataset. In the simulated dataset, we compare the interaction beta estimates to their expected values and model fit using the Akaike Information Criterion (AIC). We found that interaction beta estimates in gPPI were robust to different simulated data models, were not different from the expected beta value, and had better model fits than when using standard PPI (sPPI) methods. In the empirical dataset, we compare the model fit of the gPPI approach to sPPI. We found that the gPPI approach improved model fit compared to sPPI. There were several regions that became non-significant with gPPI. These regions all showed significantly better model fits with gPPI. Also, there were several regions where task-dependent connectivity was only detected using gPPI methods, also with improved model fit. Regions that were detected with all methods had more similar model fits. These results suggest that gPPI may have greater sensitivity and specificity than standard implementation in SPM. This notion is tempered slightly as there is no gold standard; however, data simulations with a known outcome support our

Electronic and optical device applications of hollow cathode plasma assisted atomic layer deposition based GaN thin films

International Nuclear Information System (INIS)

Bolat, Sami; Tekcan, Burak; Ozgit-Akgun, Cagla; Biyikli, Necmi; Okyay, Ali Kemal

2015-01-01

Electronic and optoelectronic devices, namely, thin film transistors (TFTs) and metal–semiconductor–metal (MSM) photodetectors, based on GaN films grown by hollow cathode plasma-assisted atomic layer deposition (PA-ALD) are demonstrated. Resistivity of GaN thin films and metal-GaN contact resistance are investigated as a function of annealing temperature. Effect of the plasma gas and postmetallization annealing on the performances of the TFTs as well as the effect of the annealing on the performance of MSM photodetectors are studied. Dark current to voltage and responsivity behavior of MSM devices are investigated as well. TFTs with the N 2 /H 2 PA-ALD based GaN channels are observed to have improved stability and transfer characteristics with respect to NH 3 PA-ALD based transistors. Dark current of the MSM photodetectors is suppressed strongly after high-temperature annealing in N 2 :H 2 ambient

Application of printed nanocrystalline diamond film for electron emission cathode

International Nuclear Information System (INIS)

Zhang Xiuxia; Wei Shuyi; Lei Chongmin; Wei Jie; Lu Bingheng; Ding Yucheng; Zhu Changchun

2011-01-01

The low-cost and large area screen-printed nano-diamond film (NDF) for electronic emission was fabricated. The edges and corners of nanocrystalline diamond are natural field-emitters. The nano-diamond paste for screen-printing was fabricated of mixing nano-graphite and other inorganic or organic vehicles. Through enough disperse in isopropyl alcohol by ultrasonic nano-diamond paste was screen-printed on the substrates to form NDF. SEM images showed that the surface morphology of NDF was improved, and the nano-diamond emitters were exposed from NDF through the special thermal-sintering technique and post-treatment process. The field emission characteristics of NDF were measured under all conditions with 10 -6 Pa pressure. The results indicated that the field emission stability and emission uniformity of NDF were improved through hydrogen plasma post-treatment process. The turn-on field decreased from 1.60 V/μm to 1.25 V/μm. The screen-printed NDF can be applied to the displays electronic emission cathode for low-cost outdoor in large area.

Development of an Optical Urea Biosensor Using Polypyrrole-polyvinyl Sulphonate Film

Directory of Open Access Journals (Sweden)

H. J. KHARAT

2009-02-01

Full Text Available Development of an intensity modulated fiber optic PPy-PVS biosensor for the detection of urea has been presented. The sensor design is based on the modified cladding technique. Polypyrrole (PPy film doped with polyvinyl sulfonate (PVS was synthesized (by in-situ chemical polymerization at room temperature with optimized process parameters. The PPy-PVS film provides good porous matrix for the immobilization of enzyme-urease on the sensing probe by cross linking via glutaraldehyde. The characterization of the urea biosensor has been carried out with an indigenously developed sensing chamber and optical fiber test bench. This biosensor showed almost stable and linear response to urea in the range 1-100 mM up to 24 days. It shows very good selectivity and repeatability.

Limited Effect of Rebamipide in Addition to Proton Pump Inhibitor (PPI) in the Treatment of Post-Endoscopic Submucosal Dissection Gastric Ulcers: A Randomized Controlled Trial Comparing PPI Plus Rebamipide Combination Therapy with PPI Monotherapy

OpenAIRE

Nakamura, Kazuhiko; Ihara, Eikichi; Akiho, Hirotada; Akahoshi, Kazuya; Harada, Naohiko; Ochiai, Toshiaki; Nakamura, Norimoto; Ogino, Haruei; Iwasa, Tsutomu; Aso, Akira; Iboshi, Yoichiro; Takayanagi, Ryoichi

2016-01-01

Background/Aims The ability of endoscopic submucosal dissection (ESD) to resect large early gastric cancers (EGCs) results in the need to treat large artificial gastric ulcers. This study assessed whether the combination therapy of rebamipide plus a proton pump inhibitor (PPI) offered benefits over PPI monotherapy. Methods In this prospective, randomized, multicenter, open-label, and comparative study, patients who had undergone ESD for EGC or gastric adenoma were randomized into groups recei...

Evolution of Calcareous Deposits and Passive Film on 304 Stainless Steel with Cathodic Polarization in Sea Water

Directory of Open Access Journals (Sweden)

Tianxiang Sun

2018-05-01

Full Text Available The change of protective current density, the formation and growth of calcareous deposits, and the evolution of passive film on 304 stainless steel (SS were investigated at different potentials of cathodic polarization in sea water. Potentiostatic polarization, electrochemical impedance spectroscopy (EIS, and surface analysis techniques of scanning electron microscopy (SEM, energy dispersive X-ray (EDX microanalysis and X-ray diffraction (XRD were used to characterize the surface conditions. It was found that the protective current density was smaller for keeping polarization at −0.80 V (vs. saturated calomel electrode (SCE, same as below than that at −0.65 V. The calcareous deposits could not be formed on 304 SS with polarization at −0.50 V while it was well protected. The formation rate, the morphology, and the constituent of the calcareous deposits depended on the applied potential. The resistance of passive film on 304 SS decreased at the first stage and then increased when polarized at −0.80 V and −0.65 V, which was related to the reduction and the repair of passive film. For the stainless steel polarized at −0.50 V, the film resistance increased with polarization time, indicating that the growth of oxide film was promoted.

Optimization of cathodic arc deposition and pulsed plasma melting techniques for growing smooth superconducting Pb photoemissive films for SRF injectors

Science.gov (United States)

Nietubyć, Robert; Lorkiewicz, Jerzy; Sekutowicz, Jacek; Smedley, John; Kosińska, Anna

2018-05-01

Superconducting photoinjectors have a potential to be the optimal solution for moderate and high current cw operating free electron lasers. For this application, a superconducting lead (Pb) cathode has been proposed to simplify the cathode integration into a 1.3 GHz, TESLA-type, 1.6-cell long purely superconducting gun cavity. In the proposed design, a lead film several micrometres thick is deposited onto a niobium plug attached to the cavity back wall. Traditional lead deposition techniques usually produce very non-uniform emission surfaces and often result in a poor adhesion of the layer. A pulsed plasma melting procedure reducing the non-uniformity of the lead photocathodes is presented. In order to determine the parameters optimal for this procedure, heat transfer from plasma to the film was first modelled to evaluate melting front penetration range and liquid state duration. The obtained results were verified by surface inspection of witness samples. The optimal procedure was used to prepare a photocathode plug, which was then tested in an electron gun. The quantum efficiency and the value of cavity quality factor have been found to satisfy the requirements for an injector of the European-XFEL facility.

Facilely solving cathode/electrolyte interfacial issue for high-voltage lithium ion batteries by constructing an effective solid electrolyte interface film

International Nuclear Information System (INIS)

Xu, Jingjing; Xia, Qingbo; Chen, Fangyuan; Liu, Tao; Li, Li; Cheng, Xueyuan; Lu, Wei; Wu, Xiaodong

2016-01-01

The cathode/electrolyte interface stability is the key factor for the cyclic performance and the safety performance of lithium ion batteries. Suppression of consuming key elements in the electrode materials is essential in this concern. In this purpose, we investigate a facile strategy to solve interfacial issue for high-voltage lithium ion batteries by adding an oxidable fluorinated phosphate, Bis(2,2,2-trifluoroethyl) Phosphite (BTFEP), as a sacrificial additive in electrolyte. We demonstrate that BTFEP additive could be oxidized at slightly above 4.28 V which is a relatively lower voltage than that of solvents, and the oxidative products facilitate in-situ forming a stable solid electrolyte interphase (SEI) film on the cathode surface. The results manifest the SEI film validly restrains the generation of HF and the interfacial side reaction between high-voltage charged LiNi 0.5 Mn 1.5 O 4 (LNMO) and electrolyte, hence, the dissolution of Mn and Ni is effectively suppressed. Finally, the cyclic performance of LNMO after 200 cycles was remarkably improved from 68.4% in blank electrolyte to 95% in 1 wt% BTFEP-adding electrolyte.

Characterization of SiC in DLC/a-Si films prepared by pulsed filtered cathodic arc using Raman spectroscopy and XPS

International Nuclear Information System (INIS)

Srisang, C.; Asanithi, P.; Siangchaew, K.; Pokaipisit, A.; Limsuwan, P.

2012-01-01

DLC/a-Si films were deposited on germanium substrates. a-Si film was initially deposited as a seed layer on the substrate using DC magnetron sputtering. DLC film was then deposited on the a-Si layer via a pulsed filtered cathodic arc (PFCA) system. In situ ellipsometry was used to monitor the thicknesses of the growth films, allowing a precise control over the a-Si and DLC thicknesses of 6 and 9 nm, respectively. It was found that carbon atoms implanting on a-Si layer act not only as a carbon source for DLC formation, but also as a source for SiC formation. The Raman peak positions at 796 cm -1 and 972 cm -1 corresponded to the LO and TO phonon modes of SiC, respectively, were observed. The results were also confirmed using TEM, XPS binding energy and XPS depth profile analysis.

PPI finder: a mining tool for human protein-protein interactions.

Directory of Open Access Journals (Sweden)

Min He

Full Text Available BACKGROUND: The exponential increase of published biomedical literature prompts the use of text mining tools to manage the information overload automatically. One of the most common applications is to mine protein-protein interactions (PPIs from PubMed abstracts. Currently, most tools in mining PPIs from literature are using co-occurrence-based approaches or rule-based approaches. Hybrid methods (frame-based approaches by combining these two methods may have better performance in predicting PPIs. However, the predicted PPIs from these methods are rarely evaluated by known PPI databases and co-occurred terms in Gene Ontology (GO database. METHODOLOGY/PRINCIPAL FINDINGS: We here developed a web-based tool, PPI Finder, to mine human PPIs from PubMed abstracts based on their co-occurrences and interaction words, followed by evidences in human PPI databases and shared terms in GO database. Only 28% of the co-occurred pairs in PubMed abstracts appeared in any of the commonly used human PPI databases (HPRD, BioGRID and BIND. On the other hand, of the known PPIs in HPRD, 69% showed co-occurrences in the literature, and 65% shared GO terms. CONCLUSIONS: PPI Finder provides a useful tool for biologists to uncover potential novel PPIs. It is freely accessible at http://liweilab.genetics.ac.cn/tm/.

Functionally Graded Cathodes for Solid Oxide Fuel Cells

International Nuclear Information System (INIS)

Lei Yang; Ze Liu; Shizhone Wang; Jaewung Lee; Meilin Liu

2008-01-01

The main objective of this DOE project is to demonstrate that the performance and long-term stability of the state-of-the-art LSCF cathode can be enhanced by a catalytically active coating (e.g., LSM or SSC). We have successfully developed a methodology for reliably evaluating the intrinsic surface catalytic properties of cathode materials. One of the key components of the test cell is a dense LSCF film, which will function as the current collector for the electrode material under evaluation to eliminate the effect of ionic and electronic transport. Since it is dense, the effect of geometry would be eliminated as well. From the dependence of the electrode polarization resistance on the thickness of a dense LSCF electrode and on partial pressure of oxygen, we have confirmed that the surface catalytic activity of LSCF limits the performances of LSCF-based cathodes. Further, we have demonstrated, using test cells of different configurations, that the performance of LSCF-based electrodes can be significantly enhanced by infiltration of a thin film of LSM or SSC. In addition, the stability of LSCF-based cathodes was also improved by infiltration of LSM or SSC. While the concept feasibility of the electrode architecture is demonstrated, many details are yet to be determined. For example, it is not clear how the surface morphology, composition, and thickness of the coatings change under operating conditions over time, how these changes influence the electrochemical behavior of the cathodes, and how to control the microscopic details of the coatings in order to optimize the performance. The selection of the catalytic materials as well as the detailed microstructures of the porous LSCF and the catalyst layer may critically impact the performance of the proposed cathodes. Further, other fundamental questions still remain; it is not clear why the degradation rates of LSCF cathodes are relatively high, why a LSM coating improves the stability of LSCF cathodes, which catalysts

Exfoliation and reassembly of cobalt oxide nanosheets into a reversible lithium-ion battery cathode.

Science.gov (United States)

Compton, Owen C; Abouimrane, Ali; An, Zhi; Palmeri, Marc J; Brinson, L Catherine; Amine, Khalil; Nguyen, SonBinh T

2012-04-10

An exfoliation-reassembly-activation (ERA) approach to lithium-ion battery cathode fabrication is introduced, demonstrating that inactive HCoO(2) powder can be converted into a reversible Li(1-x) H(x) CoO(2) thin-film cathode. This strategy circumvents the inherent difficulties often associated with the powder processing of the layered solids typically employed as cathode materials. The delamination of HCoO(2) via a combination of chemical and mechanical exfoliation generates a highly processable aqueous dispersion of [CoO(2) ](-) nanosheets that is critical to the ERA approach. Following vacuum-assisted self-assembly to yield a thin-film cathode and ion exchange to activate this material, the generated cathodes exhibit excellent cyclability and discharge capacities approaching that of low-temperature-prepared LiCoO(2) (~83 mAh g(-1) ), with this good electrochemical performance attributable to the high degree of order in the reassembled cathode. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theory, Investigation and Stability of Cathode Electrocatalytic Activity

Energy Technology Data Exchange (ETDEWEB)

Ding, Dong; Liu, Mingfei; Lai, Samson; Blinn, Kevin; Liu, Meilin

2012-09-30

The main objective of this project is to systematically characterize the surface composition, morphology, and electro-catalytic properties of catalysts coated on LSCF, aiming to establish the scientific basis for rational design of high-performance cathodes by combining a porous backbone (such as LSCF) with a thin catalyst coating. The understanding gained will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance. More specifically, the technical objectives include: (1) to characterize the surface composition, morphology, and electro-catalytic properties of catalysts coated on LSCF; (2) to characterize the microscopic details and stability of the LSCF-catalyst (e.g., LSM) interfaces; (3) to establish the scientific basis for rational design of high-performance cathodes by combining a porous backbone (such as LSCF) with a thin catalyst coating; and (4) to demonstrate that the performance and stability of porous LSCF cathodes can be enhanced by the application of a thin-film coating of LSM through a solution infiltration process in small homemade button cells and in commercially available cells of larger dimension. We have successfully developed dense, conformal LSM films with desired structure, composition, morphology, and thickness on the LSCF surfaces by two different infiltration processes: a non-aqueous and a water-based sol-gel process. It is demonstrated that the activity and stability of LSCF cathodes can be improved by the introduction of a thin-film LSM coating through an infiltration process. Surface and interface of the LSM-coated LSCF cathode were systematically characterized using advanced microscopy and spectroscopy techniques. TEM observation suggests that a layer of La and Sr oxide was formed on LSCF surfaces after annealing. With LSM infiltration, in contrast, we no longer observe such La/Sr oxide layer on the LSM-coated LSCF samples after annealing under similar

On the properties of nanocomposite amorphous carbon films prepared by off-plane double bend filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Tay, B.K.; Zhang, P.

2002-01-01

It is known to deposit hard thin films, such as tetrahedral amorphous carbon (ta-C), using a filtered cathode vacuum arc (FCVA). These ta-C films have interesting and useful properties because of the high sp 3 fraction of carbon atoms (up to 87%) in the film. However, the high internal stress in the films can limit their applications as the film may flake away from the substrate. In order to reduce the internal stress of the ta-C films and in an attempt to improve adhesion of thick films of this type, growth modifications such as incorporating metal into the ta-C films have been carried out. Nanocomposite amorphous carbon films were deposited by FCVA technique using metal-carbon composite target. Atomic force microscopy, Raman, and X-ray photoelectron spectroscopy were used to characterize the morphology and structure of the films. Nanoindenter and surface profilometer were used to determine the hardness, Young's modulus, and internal stress. The same metal composition targets for different elements results in different metal composition in the corresponding nanocomposite amorphous carbon films. We attribute this observation to the dynamic balance deposition effect of the FCVA deposition process. The influence of the type of metallic elements and its composition in the films on the structural, mechanical properties, surface energy and field emission (FE) performance was studied. The incorporation of metal into the films results in the decrease of sp 3 fraction, internal stress in the films, but the hardness and Young's modulus remains at high level. The surface energy of the films increases with incorporating Ni atoms, but decreases after incorporating Fe and Al atoms into the films. After heat-treatment, the incorporation of metal into ta-C films can greatly improve the FE performance

Annealing effect of thermal spike in MgO thin film prepared by cathodic vacuum arc deposition

Energy Technology Data Exchange (ETDEWEB)

Zhu, Daoyun, E-mail: zhudy@gdut.edu.cn [Experiment Teaching Department, Guangdong University of Technology, Guangzhou 510006 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhao, Shoubai [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510400 (China); Zheng, Changxi; Chen, Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); He, Zhenhui, E-mail: stshzh@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

2013-12-16

MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg{sup 2+} or O{sup 2-} to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 Å. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M{sub (100)} = 199 GPa, M{sub (110)} = 335 GPa and M{sub (111)} = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments. - Highlights: • MgO thin films with preferred orientation were obtained by CVAD technique. • Annealing effect of a thermal spike in MgO film was discussed. • Lattice spacing of MgO film decreased with the increase of bias voltage. • Film preferred orientation changed from (200) to (220) as the bias voltage increased.

The optimization of molybdenum back contact films for Cu(In,Ga)Se{sub 2} solar cells by the cathodic arc ion plating method

Energy Technology Data Exchange (ETDEWEB)

Cho, Yong Ki, E-mail: choyk@kitech.re.kr [Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Gang Sam; Song, Young Sik; Lim, Tae Hong [Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Jung, Donggeun [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2013-12-02

Molybdenum back contact films for Cu(In,Ga)Se{sub 2} (CIGS) solar cells have been deposited using DC magnetron sputtering methods. The electronic pathway properties of the molybdenum film have been highly dependent on the working gas pressure in magnetron sputtering, which should be carefully controlled to obtain high conductivity and adhesion. A coating method, cathodic arc ion plating, was used for molybdenum back contact electrode fabrication. The aim of this work was to find a metallization method for CIGS solar cells, which has less sensitivity on the working pressure. The resistivity, grain size, growth structures, stress, and efficiency of the films in CIGS solar cells were investigated. The results reveal that the growth structures of the molybdenum films mainly affect the conductivity. The lowest electrical resistivity of the ion-plated molybdenum films was 6.9 μΩ-cm at a pressure of 0.7 Pa. The electrical resistivity variation showed a gently increasing slope with linearity under a working gas pressure of 13.3 Pa. However, a high value of the residual stress of over 1.3 GPa was measured. In order to reduce stress, titanium film was selected as the buffer layer material, and the back contact films were optimized by double-layer coating of two kinds of hetero-materials with arc ion plating. CIGS solar cells prepared molybdenum films to measure the efficiency and to examine the effects of the back contact electrode. The resistivity, grain size, and surface morphology of molybdenum films were measured by four-point probe, X-ray diffraction, and a scanning electron microscope. The residual stress of the films was calculated from differences in bending curvatures measured using a laser beam. - Highlights: • Molybdenum back contact films for Cu(In,Ga)Se{sub 2} solar cells were prepared by the cathodic arc ion plating. • The lowest electrical resistivity of molybdenum film was 6.9 μΩ-cm. • Titanium buffer layer reduced the compressive residual stress

Air cathode structure manufacture

Science.gov (United States)

Momyer, William R.; Littauer, Ernest L.

1985-01-01

An improved air cathode structure for use in primary batteries and the like. The cathode structure includes a matrix active layer, a current collector grid on one face of the matrix active layer, and a porous, nonelectrically conductive separator on the opposite face of the matrix active layer, the collector grid and separator being permanently bonded to the matrix active layer. The separator has a preselected porosity providing low IR losses and high resistance to air flow through the matrix active layer to maintain high bubble pressure during operation of the battery. In the illustrated embodiment, the separator was formed of porous polypropylene. A thin hydrophobic film is provided, in the preferred embodiment, on the current collecting metal grid.

Influence of substrate bias on the structure and properties of (Ti, Al)N films deposited by filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Cheng, Y.H.; Tay, B.K.; Lau, S.P.; Shi, X.

2001-01-01

(Ti, Al)N films were deposited by an off-plane, double-bend, filtered cathodic vacuum arc technique in N 2 atmosphere at room temperature. The (Ti, Al)N films deposited are atomically smooth. The influence of substrate negative bias at the wide range (0-1000 V) on the deposition rate, surface morphology, crystal structure, internal stress, and mechanical properties of (Ti, Al)N films were systematically studied. Increasing substrate bias results in the decrease of deposition rate and the increase of surface roughness monotonically. At the bias of 0 V, (Ti, Al)N films are amorphous, and the internal stress, hardness, and Young's modulus for the deposited films are fairly low. With increasing substrate bias to 200 V, single-phase face-centered cubic-type nanocrystalline (Ti, Al)N films can be obtained, and the internal stress, hardness, and Young's modulus increase to the maximum of 7 GPa, 28 GPa, and 240 GPa, respectively. Further increase of substrate bias results in the decrease of intensity and the broadening of x-ray diffraction lines, and the gradual decrease of internal stress, hardness, and Young's modulus in (Ti, Al)N films

Influence of pulsed substrate bias on the structure and properties of Ti-Al-N films deposited by cathodic vacuum arc

Energy Technology Data Exchange (ETDEWEB)

Zhang, G.P., E-mail: princeterry@163.com [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); Gao, G.J. [Changchun University of Science and Technology, College of Science, Changchun 130000 (China); Wang, X.Q.; Lv, G.H.; Zhou, L.; Chen, H.; Pang, H.; Yang, S.Z. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China)

2012-07-15

Ti-Al-N films were deposited by cathodic vacuum arc (CVA) technique in N{sub 2} atmosphere with different pulsed substrate bias. The influence of pulsed substrate bias (0 to -800 V) on the deposition rate, surface morphology, crystal structure, and mechanical properties of the Ti-Al-N films were systematically investigated. Increasing pulsed bias voltage resulted in the decrease of deposition rate but the increase of surface roughness. It was found that there was a strong correlation between the pulsed bias and film structure. All the films studied in this paper were composed of TiN, AlN, and Ti-Al-N ternary phases. The grains changed from equiaxial to columnar and exhibited preferred orientation when the pulsed bias increased. With the increase of pulsed bias voltage, the atomic ratio of Ti to Al element increased gradually, while the N to (Ti + Al) ratio decreased. The composite films present an enhanced nanohardness compared with binary TiN and ZrN films. The film deposited with pulsed bias of -200 V possessed the maximum scratch critical load and nanohardness. The minimum friction coefficient with pulsed bias of -300 V was obtained.

Magnetron sputtered zinc oxide nanorods as thickness-insensitive cathode interlayer for perovskite planar-heterojunction solar cells.

Science.gov (United States)

Liang, Lusheng; Huang, Zhifeng; Cai, Longhua; Chen, Weizhong; Wang, Baozeng; Chen, Kaiwu; Bai, Hua; Tian, Qingyong; Fan, Bin

2014-12-10

Suitable electrode interfacial layers are essential to the high performance of perovskite planar heterojunction solar cells. In this letter, we report magnetron sputtered zinc oxide (ZnO) film as the cathode interlayer for methylammonium lead iodide (CH3NH3PbI3) perovskite solar cell. Scanning electron microscopy and X-ray diffraction analysis demonstrate that the sputtered ZnO films consist of c-axis aligned nanorods. The solar cells based on this ZnO cathode interlayer showed high short circuit current and power conversion efficiency. Besides, the performance of the device is insensitive to the thickness of ZnO cathode interlayer. Considering the high reliability and maturity of sputtering technique both in lab and industry, we believe that the sputtered ZnO films are promising cathode interlayers for perovskite solar cells, especially in large-scale production.

Cathodic disbonding of organic coatings on submerged steel

Energy Technology Data Exchange (ETDEWEB)

Knudsen, Ole oeystein

1998-12-31

In offshore oil production, submerged steel structures are commonly protected by an organic coating in combination with cathodic protection. The main advantage is that the coating decreases the current demand for cathodic protection. But the coating degrades with time. This thesis studies one of the most important mechanisms for coating degradation in seawater, cathodic disbonding. Seven commercial coatings and two model coatings with various pigmentations have been studied. Parameter studies, microscopy and studies of free films were used in the mechanism investigations. Exposure to simulated North Sea conditions was used in the performance studies. The effect of aluminium and glass barrier pigments on cathodic disbonding was investigated. The mechanism for the effect of the aluminium pigments on cathodic disbonding was also investigated. The transport of charge and oxygen to the steel/coating interface during cathodic disbonding was studied for two epoxy coatings. Cathodic disbonding, blistering and current demand for cathodic protection was measured for nine commercial coatings for submerged steel structures, using the ASTM-G8 standard test and a long term test under simulated North Sea conditions. The relevance of the ASTM-G8 test as a prequalification test was evaluated. 171 refs., 40 figs., 6 tabs.

Electrochemomechanical constrained multiobjective optimization of PPy/MWCNT actuators

International Nuclear Information System (INIS)

Khalili, N; Naguib, H E; Kwon, R H

2014-01-01

Polypyrrole (PPy) conducting polymers have shown a great potential for the fabrication of conjugated polymer-based actuating devices. Consequently, they have been a key point in developing many advanced emerging applications such as biomedical devices and biomimetic robotics. When designing an actuator, taking all of the related decision variables, their roles and relationships into consideration is of pivotal importance to determine the actuator’s final performance. Therefore, the central focus of this study is to develop an electrochemomechanical constrained multiobjective optimization model of a PPy/MWCNTs trilayer actuator. For this purpose, the objective functions are designed to capture the three main characteristics of these actuators, namely their tip vertical displacement, blocking force and response time. To obtain the optimum range of the designated decision variables within the feasible domain, a multiobjective optimization algorithm is applied while appropriate constraints are imposed. The optimum points form a Pareto surface on which they are consistently spread. The numerical results are presented; these results enable one to design an actuator with consideration to the desired output performances. For the experimental analysis, a multilayer bending-type actuator is fabricated, which is composed of a PVDF layer and two layers of PPy with an incorporated layer of multi-walled carbon nanotubes deposited on each side of the PVDF membrane. The numerical results are experimentally verified; in order to determine the performance of the fabricated actuator, its outputs are compared with a neat PPy actuator’s experimental and numerical counterparts. (paper)

Gold Nanoclusters@Ru(bpy)₃²⁺-Layered Double Hydroxide Ultrathin Film as a Cathodic Electrochemiluminescence Resonance Energy Transfer Probe.

Science.gov (United States)

Yu, Yingchang; Lu, Chao; Zhang, Meining

2015-08-04

Herein, it is the first report that a cathodic electrochemiluminescence (ECL) resonance energy transfer (ERET) system is fabricated by layer-by-layer (LBL) electrostatic assembly of CoAl layered double hydroxide (LDH) nanosheets with a mixture of blue BSA-gold nanoclusters (AuNCs) and Ru(bpy)3(2+) (denoted as AuNCs@Ru) on an Au electrode. The possible ECL mechanism indicates that the appearance of CoAl-LDH nanosheets generates a long-range stacking order of the AuNCs@Ru on an Au electrode, facilitating the occurrence of the ERET between BSA-AuNC donors and Ru(bpy)3(2+) acceptors on the as-prepared AuNCs@Ru-LDH ultrathin films (UTFs). Furthermore, it is observed that the cathodic ECL intensity can be quenched efficiently in the presence of 6-mercaptopurine (6-MP) in a linear range of 2.5-100 nM with a detection limit of 1.0 nM. On the basis of these interesting phenomena, a facile cathodic ECL sensor has successfully distinguished 6-MP from other thiol-containing compounds (e.g., cysteine and glutathione) in human serum and urine samples. The proposed sensing scheme opens a way for employing the layered UTFs as a platform for the cathodic ECL of Ru(bpy)3(2+).

Surfing the Protein-Protein Interaction Surface Using Docking Methods: Application to the Design of PPI Inhibitors.

Science.gov (United States)

Sable, Rushikesh; Jois, Seetharama

2015-06-23

Blocking protein-protein interactions (PPI) using small molecules or peptides modulates biochemical pathways and has therapeutic significance. PPI inhibition for designing drug-like molecules is a new area that has been explored extensively during the last decade. Considering the number of available PPI inhibitor databases and the limited number of 3D structures available for proteins, docking and scoring methods play a major role in designing PPI inhibitors as well as stabilizers. Docking methods are used in the design of PPI inhibitors at several stages of finding a lead compound, including modeling the protein complex, screening for hot spots on the protein-protein interaction interface and screening small molecules or peptides that bind to the PPI interface. There are three major challenges to the use of docking on the relatively flat surfaces of PPI. In this review we will provide some examples of the use of docking in PPI inhibitor design as well as its limitations. The combination of experimental and docking methods with improved scoring function has thus far resulted in few success stories of PPI inhibitors for therapeutic purposes. Docking algorithms used for PPI are in the early stages, however, and as more data are available docking will become a highly promising area in the design of PPI inhibitors or stabilizers.

Photoluminescence from PP-HMDSO thin films deposited using a remote plasma of 13.56 MHz hollow cathode discharge

International Nuclear Information System (INIS)

Naddaf, M; Saloum, S; Hamadeh, H

2007-01-01

Room temperature photoluminescence (PL) from plasma-polymerized hexamethyldisiloxane (PP-HMDSO) thin films deposited on silicon wafers has been investigated as a function of both the applied RF power and the monomer flow rate. Films were deposited in a low pressure-low temperature remote plasma ignited in a 13.56 MHz hollow cathode discharge reactor, using pure HMDSO as a monomer and Ar as a feed gas. The substrate temperature during the deposition was as low as 40 deg. C and the total pressure was about 0.03 mbar. Optical emission spectroscopy (OES) has been used as in situ tool for monitoring the different chemical species present in the plasma during deposition processes. The deposited PP-HMDSO films showed a strong, broad 'green/yellow' PL band. The RF power and the flow rate of the HMDSO monomer are found to have a significant impact on the PL intensity of the deposited film. The changes in the chemical bonding of the film as a function of deposition parameters have been investigated by using the Fourier transform infrared (FTIR) spectroscopic analysis and are related to PL and OES results. The 'green/yellow' PL band is ascribed to chemical groups and bonds of silicon, hydrogen and/or oxygen constituting the films, in particular, SiH, SiO bonds and silanol Si-O-H groups

Photoluminescence from PP-HMDSO thin films deposited using a remote plasma of 13.56 MHz hollow cathode discharge

Science.gov (United States)

Naddaf, M.; Saloum, S.; Hamadeh, H.

2007-07-01

Room temperature photoluminescence (PL) from plasma-polymerized hexamethyldisiloxane (PP-HMDSO) thin films deposited on silicon wafers has been investigated as a function of both the applied RF power and the monomer flow rate. Films were deposited in a low pressure-low temperature remote plasma ignited in a 13.56 MHz hollow cathode discharge reactor, using pure HMDSO as a monomer and Ar as a feed gas. The substrate temperature during the deposition was as low as 40 °C and the total pressure was about 0.03 mbar. Optical emission spectroscopy (OES) has been used as in situ tool for monitoring the different chemical species present in the plasma during deposition processes. The deposited PP-HMDSO films showed a strong, broad 'green/yellow' PL band. The RF power and the flow rate of the HMDSO monomer are found to have a significant impact on the PL intensity of the deposited film. The changes in the chemical bonding of the film as a function of deposition parameters have been investigated by using the Fourier transform infrared (FTIR) spectroscopic analysis and are related to PL and OES results. The 'green/yellow' PL band is ascribed to chemical groups and bonds of silicon, hydrogen and/or oxygen constituting the films, in particular, SiH, SiO bonds and silanol Si-O-H groups.

Photoluminescence from PP-HMDSO thin films deposited using a remote plasma of 13.56 MHz hollow cathode discharge

Energy Technology Data Exchange (ETDEWEB)

Naddaf, M; Saloum, S; Hamadeh, H [Department of Physics, Atomic Energy Commission of Syria (AECS), PO Box 6091, Damascus (Syrian Arab Republic)

2007-07-07

Room temperature photoluminescence (PL) from plasma-polymerized hexamethyldisiloxane (PP-HMDSO) thin films deposited on silicon wafers has been investigated as a function of both the applied RF power and the monomer flow rate. Films were deposited in a low pressure-low temperature remote plasma ignited in a 13.56 MHz hollow cathode discharge reactor, using pure HMDSO as a monomer and Ar as a feed gas. The substrate temperature during the deposition was as low as 40 deg. C and the total pressure was about 0.03 mbar. Optical emission spectroscopy (OES) has been used as in situ tool for monitoring the different chemical species present in the plasma during deposition processes. The deposited PP-HMDSO films showed a strong, broad 'green/yellow' PL band. The RF power and the flow rate of the HMDSO monomer are found to have a significant impact on the PL intensity of the deposited film. The changes in the chemical bonding of the film as a function of deposition parameters have been investigated by using the Fourier transform infrared (FTIR) spectroscopic analysis and are related to PL and OES results. The 'green/yellow' PL band is ascribed to chemical groups and bonds of silicon, hydrogen and/or oxygen constituting the films, in particular, SiH, SiO bonds and silanol Si-O-H groups.

Photoluminescence from PP-HMDSO thin films deposited using a remote plasma of 13.56 MHz hollow cathode discharge

International Nuclear Information System (INIS)

Naddaf, M.; Saloum, S.; Hamadeh, H.

2008-01-01

Room temperature photoluminescence (PL) from plasma-polymerized hexamethyldisiloxane (PP-HMDSO) thin films deposited on silicon wafers has been investigated as a function of both the applied RF power and the monomer flow rate. Films were deposited in a low pressure-low temperature remote plasma ignited in a 13.56 MHz hollow cathode discharge reactor, using pure HMDSO as a monomer and Ar as a feed gas. The substrate temperature during the deposition was as low as 40 deg. C and the total pressure was about 0.03 mbar. Optical emission spectroscopy (OES) has been used as in situ tool for monitoring the different chemical species present in the plasma during deposition processes. The deposited PP-HMDSO films showed a strong, broad 'green/yellow' PL band. The RF power and the flow rate of the HMDSO monomer are found to have a significant impact on the PL intensity of the deposited film. The changes in the chemical bonding of the film as a function of deposition parameters have been investigated by using the Fourier transform infrared (FTIR) spectroscopic analysis and are related to PL and OES results. The 'green/yellow' PL band is ascribed to chemical groups and bonds of silicon, hydrogen and/or oxygen constituting the films, in particular, SiH, SiO bonds and silanol Si-O-H groups. (Authors)

Mesoscale Elucidation of Surface Passivation in the Li-Sulfur Battery Cathode.

Science.gov (United States)

Liu, Zhixiao; Mukherjee, Partha P

2017-02-15

The cathode surface passivation caused by Li 2 S precipitation adversely affects the performance of lithium-sulfur (Li-S) batteries. Li 2 S precipitation is a complicated mesoscale process involving adsorption, desorption and diffusion kinetics, which are affected profoundly by the reactant concentration and operating temperature. In this work, a mesoscale interfacial model is presented to study the growth of Li 2 S film on carbon cathode surface. Li 2 S film growth experiences nucleation, isolated Li 2 S island growth and island coalescence. The slow adsorption rate at small S 2- concentration inhibits the formation of nucleation seeds and the lateral growth of Li 2 S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Li 2 S nucleation seeds form in such an operating temperature range, thereby facilitating heterogeneous growth and potentially inhibiting the lateral growth of the Li 2 S film, which may ultimately result in reduced surface passivation. The high specific surface area of the cathode microstructure is expected to mitigate the surface passivation.

A novel modified electrode as GC/PPy-AuNPs-rGO/L-Cys/Ag@MUA nanostructure configuration for determination of CCP and CRP antibodies in human blood serum samples.

Science.gov (United States)

Babakhanian, Arash; Ehzari, Hosna; Kaki, Samineh; Hamidi, Zohreh

2015-01-15

In this work, silver nanoparticles were synthesized and stabilized with 11-mercaptoundecanoateanions to produce a new Ag@MUA core shell structure, and its utilizing for fabrication of a new sensing film. Gold nanoparticles (AuNPs) were electrochemically produced and simultaneously immobilized into the electropolymerized polypyrrole (PPy) film with the reduced graphene oxide (rGO). The Ag@MUA was then grafted to the surface of GC/PPy-AuNPs-rGO film using L-cysteine (L-Cys) linker agent and trifluoromethanesulfonic anhydride (TF2O), at ambient temperature and under the electrode stirring. The characterization of the sensor was studied by scanning electron microscopy, electrochemical impedance spectroscopy, cyclic and square wave voltammetry techniques. The utility of the modified electrode for clinical diagnosis has been successfully demonstrated by the analysis of human blood serums with a certified CRP and CCP content. Thus, the proposed sensor shows simple preparation, accuracy and precision in the analysis of cytochrome c protein (CCP) and C-reactive protein (CRP (with less side interferences. Copyright © 2014 Elsevier B.V. All rights reserved.

Surfing the Protein-Protein Interaction Surface Using Docking Methods: Application to the Design of PPI Inhibitors

Directory of Open Access Journals (Sweden)

Rushikesh Sable

2015-06-01

Full Text Available Blocking protein-protein interactions (PPI using small molecules or peptides modulates biochemical pathways and has therapeutic significance. PPI inhibition for designing drug-like molecules is a new area that has been explored extensively during the last decade. Considering the number of available PPI inhibitor databases and the limited number of 3D structures available for proteins, docking and scoring methods play a major role in designing PPI inhibitors as well as stabilizers. Docking methods are used in the design of PPI inhibitors at several stages of finding a lead compound, including modeling the protein complex, screening for hot spots on the protein-protein interaction interface and screening small molecules or peptides that bind to the PPI interface. There are three major challenges to the use of docking on the relatively flat surfaces of PPI. In this review we will provide some examples of the use of docking in PPI inhibitor design as well as its limitations. The combination of experimental and docking methods with improved scoring function has thus far resulted in few success stories of PPI inhibitors for therapeutic purposes. Docking algorithms used for PPI are in the early stages, however, and as more data are available docking will become a highly promising area in the design of PPI inhibitors or stabilizers.

Formation of a percolating cluster in films prepared by cathodic electrodeposition of a mixture of lower and higher molecular weight epoxy-amine adducts.

Science.gov (United States)

Ranjbar, Zahra; Moradian, Siamak; Rastegar, Saeed

2003-08-15

The electrodeposition behavior of blends of primary dispersions of a lower and a higher molecular weight epoxy-amine adduct has been investigated. The throwing power of the above-mentioned blends showed a voltage-dependent critical composition at which the throwing power dropped to a much lower value. This was assigned to the formation of an infinite conducting cluster, the extension of which is dependent on the rate of the electrocoagulation process at the cathode boundary. The random resistor network approach of Stauffer (RRNS) and the random resistor network approach of Miller and Abrahams (RRNMA) were applied to the experimental data with high correlations (r2=0.9314 and 0.9699). The percolating cluster formed within the film, however, gave a critical exponent of conductivity equal to 1.1028, much less than expected from a classical three-dimensional lattice (i.e., 1.5-2.0). This discrepancy was explained in terms of the changed behavior of the film resulting from the bubbles formed near the cathode and its effect on the infinite conducting cluster.

HomPPI: a class of sequence homology based protein-protein interface prediction methods

Directory of Open Access Journals (Sweden)

Dobbs Drena

2011-06-01

Full Text Available Abstract Background Although homology-based methods are among the most widely used methods for predicting the structure and function of proteins, the question as to whether interface sequence conservation can be effectively exploited in predicting protein-protein interfaces has been a subject of debate. Results We studied more than 300,000 pair-wise alignments of protein sequences from structurally characterized protein complexes, including both obligate and transient complexes. We identified sequence similarity criteria required for accurate homology-based inference of interface residues in a query protein sequence. Based on these analyses, we developed HomPPI, a class of sequence homology-based methods for predicting protein-protein interface residues. We present two variants of HomPPI: (i NPS-HomPPI (Non partner-specific HomPPI, which can be used to predict interface residues of a query protein in the absence of knowledge of the interaction partner; and (ii PS-HomPPI (Partner-specific HomPPI, which can be used to predict the interface residues of a query protein with a specific target protein. Our experiments on a benchmark dataset of obligate homodimeric complexes show that NPS-HomPPI can reliably predict protein-protein interface residues in a given protein, with an average correlation coefficient (CC of 0.76, sensitivity of 0.83, and specificity of 0.78, when sequence homologs of the query protein can be reliably identified. NPS-HomPPI also reliably predicts the interface residues of intrinsically disordered proteins. Our experiments suggest that NPS-HomPPI is competitive with several state-of-the-art interface prediction servers including those that exploit the structure of the query proteins. The partner-specific classifier, PS-HomPPI can, on a large dataset of transient complexes, predict the interface residues of a query protein with a specific target, with a CC of 0.65, sensitivity of 0.69, and specificity of 0.70, when homologs of

PpiA, a surface PPIase of the cyclophilin family in Lactococcus lactis.

Directory of Open Access Journals (Sweden)

Nicolas Trémillon

Full Text Available BACKGROUND: Protein folding in the envelope is a crucial limiting step of protein export and secretion. In order to better understand this process in Lactococcus lactis, a lactic acid bacterium, genes encoding putative exported folding factors like Peptidyl Prolyl Isomerases (PPIases were searched for in lactococcal genomes. RESULTS: In L. lactis, a new putative membrane PPIase of the cyclophilin subfamily, PpiA, was identified and characterized. ppiA gene was found to be constitutively expressed under normal and stress (heat shock, H(2O(2 conditions. Under normal conditions, PpiA protein was synthesized and released from intact cells by an exogenously added protease, showing that it was exposed at the cell surface. No obvious phenotype could be associated to a ppiA mutant strain under several laboratory conditions including stress conditions, except a very low sensitivity to H(2O(2. Induction of a ppiA copy provided in trans had no effect i on the thermosensitivity of an mutant strain deficient for the lactococcal surface protease HtrA and ii on the secretion and stability on four exported proteins (a highly degraded hybrid protein and three heterologous secreted proteins in an otherwise wild-type strain background. However, a recombinant soluble form of PpiA that had been produced and secreted in L. lactis and purified from a culture supernatant displayed both PPIase and chaperone activities. CONCLUSIONS: Although L. lactis PpiA, a protein produced and exposed at the cell surface under normal conditions, displayed a very moderate role in vivo, it was found, as a recombinant soluble form, to be endowed with folding activities in vitro.

Association of Proton Pump Inhibitor (PPI Use with Energy Intake, Physical Activity, and Weight Gain

Directory of Open Access Journals (Sweden)

Jennifer L. Czwornog

2015-10-01

Full Text Available Studies suggest proton pump inhibitor (PPI use impacts body weight regulation, though the effect of PPIs on energy intake, energy extraction, and energy expenditure is unknown. We used data on 3073 eligible adults from the National Health and Nutrition Examination Survey (NHANES. Medication use, energy intake, diet composition, and physical activity were extracted from NHANES. Multivariate regression models included confounding variables. Daily energy intake was similar between PPI users and non-users (p = 0.41. Diet composition was similar between the two groups, except that PPI users consumed a slightly greater proportion of calories from fat (34.5% vs. 33.2%; p = 0.02. PPI users rated themselves as being as physically active as their age/gender-matched peers and reported similar frequencies of walking or biking. However, PPI users were less likely to have participated in muscle-strengthening activities (OR: 0.53; 95% CI: 0.30–0.95. PPI users reported similar sedentary behaviors to non-users. Male PPI users had an increase in weight (of 1.52 ± 0.59 kg; p = 0.021 over the previous year compared to non-users, while female PPI users had a non-significant increase in weight. The potential mechanisms for PPI-associated weight gain are unclear as we did not find evidence for significant differences in energy intake or markers of energy expenditure.

Single-layer nano-carbon film, diamond film, and diamond/nano-carbon composite film field emission performance comparison

International Nuclear Information System (INIS)

Wang, Xiaoping; Wang, Jinye; Wang, Lijun

2016-01-01

A series of single-layer nano-carbon (SNC) films, diamond films, and diamond/nano-carbon (D/NC) composite films have been prepared on the highly doped silicon substrate by using microwave plasma chemical vapor deposition techniques. The films were characterised by scanning electron microscopy, Raman spectroscopy, and field emission I-V measurements. The experimental results indicated that the field emission maximum current density of D/NC composite films is 11.8–17.8 times that of diamond films. And the field emission current density of D/NC composite films is 2.9–5 times that of SNC films at an electric field of 3.0 V/μm. At the same time, the D/NC composite film exhibits the advantage of improved reproducibility and long term stability (both of the nano-carbon film within the D/NC composite cathode and the SNC cathode were prepared under the same experimental conditions). And for the D/NC composite sample, a high current density of 10 mA/cm"2 at an electric field of 3.0 V/μm was obtained. Diamond layer can effectively improve the field emission characteristics of nano-carbon film. The reason may be due to the diamond film acts as the electron acceleration layer.

Plasma-induced field emission and plasma expansion of carbon nanotube cathodes

International Nuclear Information System (INIS)

Liao Qingliang; Zhang Yue; Qi Junjie; Huang Yunhua; Xia Liansheng; Gao Zhanjun; Gu Yousong

2007-01-01

High intensity electron emission cathodes based on carbon nanotube films have been successfully fabricated. An investigation of the explosive field emission properties of the carbon nanotube cathode in a double-pulse mode was presented and a high emission current density of 245 A cm -2 was obtained. The formation of the cathode plasma layer was proved and the production process of the electron beams from the cathode was explained. The time and space resolution of the electron beams flow from the cathode was investigated. The plasma expanded at a velocity of ∼8.17 cm μs -1 towards the anode and influenced on the intensity and distribution of electron beams obviously. The formation of cathode plasma had no preferential position and the local enhancement of electron beams was random. This carbon nanotube cathode appears to be suitable for high-power microwave device applications

Improved antibacterial behavior of titanium surface with torularhodin–polypyrrole film

International Nuclear Information System (INIS)

Ungureanu, Camelia; Popescu, Simona; Purcel, Gabriela; Tofan, Vlad; Popescu, Marian; Sălăgeanu, Aurora; Pîrvu, Cristian

2014-01-01

The problem of microorganisms attaching and proliferating on implants and medical devices surfaces is still attracting interest in developing research on different coatings based on antibacterial agents. The aim of this work is centered on modifying titanium (Ti) based implants surfaces through incorporation of a natural compound with antimicrobial effect, torularhodin (T), by means of a polypyrrole (PPy) film. This study tested the potential antimicrobial activity of the new coating against a range of standard bacterial strains: Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and Pseudomonas aeruginosa. The morphology, physical and electrochemical properties of the synthesized films were assessed by SEM, AFM, UV–Vis, FTIR and cyclic voltammetry. In addition, biocompatibility of this new coating was evaluated using L929 mouse fibroblast cells. The results showed that PPy–torularhodin composite film acts as a corrosion protective coating with antibacterial activity and it has no harmful effect on cell viability. - Highlights: • Modification of titanium surfaces by incorporating a natural compound • new PPy - torularhodin corrosion protective composite coatings • antibacterial activity for the new PPy - torularhodin coating • cytocompatibility of new coating was demonstrated using mouse fibroblast cells

Improved antibacterial behavior of titanium surface with torularhodin–polypyrrole film

Energy Technology Data Exchange (ETDEWEB)

Ungureanu, Camelia; Popescu, Simona; Purcel, Gabriela [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania); Tofan, Vlad [“Cantacuzino” National Institute of Research-Development for Microbiology and Immunology, 103 Splaiul Independentei, Sector 5, 050096 Bucharest (Romania); Popescu, Marian [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania); National Institute for Research and Development in Microtechnologies, 126A, Erou Iancu Nicolae Street, 077190 Bucharest (Romania); Sălăgeanu, Aurora [“Cantacuzino” National Institute of Research-Development for Microbiology and Immunology, 103 Splaiul Independentei, Sector 5, 050096 Bucharest (Romania); Pîrvu, Cristian, E-mail: c_pirvu@chim.pub.ro [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania)

2014-09-01

The problem of microorganisms attaching and proliferating on implants and medical devices surfaces is still attracting interest in developing research on different coatings based on antibacterial agents. The aim of this work is centered on modifying titanium (Ti) based implants surfaces through incorporation of a natural compound with antimicrobial effect, torularhodin (T), by means of a polypyrrole (PPy) film. This study tested the potential antimicrobial activity of the new coating against a range of standard bacterial strains: Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and Pseudomonas aeruginosa. The morphology, physical and electrochemical properties of the synthesized films were assessed by SEM, AFM, UV–Vis, FTIR and cyclic voltammetry. In addition, biocompatibility of this new coating was evaluated using L929 mouse fibroblast cells. The results showed that PPy–torularhodin composite film acts as a corrosion protective coating with antibacterial activity and it has no harmful effect on cell viability. - Highlights: • Modification of titanium surfaces by incorporating a natural compound • new PPy - torularhodin corrosion protective composite coatings • antibacterial activity for the new PPy - torularhodin coating • cytocompatibility of new coating was demonstrated using mouse fibroblast cells.

77 FR 76303 - Notice of Availability of Producer Price Index (PPI) Data Users Survey

Science.gov (United States)

2012-12-27

...) Data Users Survey AGENCY: Bureau of Labor Statistics, Labor. ACTION: Notice of availability of survey... Index (PPI) data users. The survey is necessary to: Identify PPI data users, see how they use our data... conducted a survey of PPI data users in late 1976 through early 1977. Since that time, numerous new time...

Co-sputtered optical films

Energy Technology Data Exchange (ETDEWEB)

Misiano, C; Simonetti, E [Selenia S.p.A., Rome (Italy)

1977-06-01

The co-sputtering of two dielectric materials with indices of refraction as widely different as possible has been investigated with the aim of obtaining both homogeneous films with an intermediate index of refraction and inhomogeneous films with predetermined profiles. An rf sputtering module is described which has been especially designed, with two separate cathodes and two independent tunable rf generators. The substrates are placed on a circular anode rotating underneath the two cathodes. So far mainly CeO/sub 2/, TiO2 and SiO/sub 2/ targets have been used. The deposition rate from each cathode and the total film thickness are determined by means of two quartz thickness monitors, sputtering compatible. Values obtained for the refractive index and optical thickness are reported, as well as repeatability, mechanical and chemical characteristics, reliability and high power optical radiation resistance. Finally, results obtained on optical components of practical interest are discussed.

Research and Development of a New Field Enhanced Low Temperature Thermionic Cathode that Enables Fluorescent Dimming and Loan Shedding without Auxiliary Cathode Heating

Energy Technology Data Exchange (ETDEWEB)

Feng Jin

2009-01-07

This is the final report for project entitled 'Research and development of a new field enhanced low temperature thermionic cathode that enables fluorescent dimming and load shedding without auxiliary cathode heating', under Agreement Number: DE-FC26-04NT-42329. Under this project, a highly efficient CNT based thermionic cathode was demonstrated. This cathode is capable of emitting electron at a current density two order of magnitude stronger then a typical fluorescent cathode at same temperatures, or capable of emitting at same current density but at temperature about 300 C lower than that of a fluorescent cathode. Detailed fabrication techniques were developed including CVD growth of CNTs and sputter deposition of oxide thin films on CNTs. These are mature technologies that have been widely used in industry for large scale materials processing and device fabrications, thus, with further development work, the techniques developed in this project can be scaled-up in manufacturing environment. The prototype cathodes developed in this project were tested in lighting plasma discharge environment. In many cases, they not only lit and sustain the plasma, but also out perform the fluorescent cathodes in key parameters such like cathode fall voltages. More work will be needed to further evaluate more detailed and longer term performance of the prototype cathode in lighting plasma.

Structural evolution of bias sputtered LiNi0.5Mn1.5O4 thin film cathodes for lithium ion batteries

International Nuclear Information System (INIS)

Su, Shih-Hsuan; Chiu, Kuo-Feng; Leu, Hoang-Jyh

2014-01-01

LiNi 0.5 Mn 1.5 O 4 (LNMO) thin films have been deposited on stainless steel substrates using radio frequency (f = 13.56 MHz) magnetron sputtering, followed by thermal annealing in ambient atmosphere. Various negative biases were applied on the substrates during deposition. The structural evolution of LNMO thin films under different negative biases has been investigated and characterized by X-ray diffraction. All of the deposited films exhibit a crystalline spinel structure with a space group of Fd-3m, which is a so-called disordered phase. The results also indicate that particle size decreases with increasing negative bias. The electrochemical properties of the LNMO thin films as cathode materials for lithium ion batteries were investigated. Two distinctive voltage plateaus at ∼ 4.7 V and at ∼ 4.0 V (vs. Li + /Li) can be observed in the discharge curves, corresponding to the reactions of the disordered phase. The capacity of LNMO thin film electrodes under suitable negative bias can be optimized. - Highlights: • LiNi 0.5 Mn 1.5 O 4 thin films have been deposited on stainless steel substrates. • Various negative biases were applied on the substrates during deposition. • The particle sizes of LNMO thin films decrease with increasing negative bias

Effect of self-bias voltage on the wettability, chemical functionality and nanomechanical properties of hexamethyldisiloxane films

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, M.D.F. [Program of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro (UFRJ), P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Santos, E. [Program of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro (UFRJ), P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Faculty of Civil Engineering, University Center of Volta Redonda (UniFOA), Volta Redonda, RJ (Brazil); Perdone, R.R.T. [Program of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro (UFRJ), P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Simao, R.A., E-mail: renata@metalmat.ufrj.br [Program of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro (UFRJ), P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil)

2014-08-01

Copper and silicon substrates were coated by chemical vapor deposition using hexamethyldisiloxane (HMDSO) as the precursor gas. Substrates were placed both at the anode and cathode of a glow discharge reactor, and films were deposited using different self-bias voltages. This study focuses on comparing the differences between the hydrophilicity, polymeric character, chemical structure and nanomechanical properties of HMDSO films produced at the cathode and anode of the reactor at different self-bias voltages. Fourier transform infrared spectroscopy and Raman confocal spectroscopy indicated a significant increase in the content of organic groups when films were deposited at the anode. Analyzing the nanomechanical properties of the cathode and anode films indicated that the penetration depth was higher for samples prepared at the cathode (lower hardness) compared with the samples produced at the anode. The measured contact angles indicated that all samples became hydrophobic with water contact angles close to 100°; however, a different lyophobic character was observed when diiodomethane was used. Films produced at the anode with diiodomethane exhibited higher contact angles than did films produced at the cathode. - Highlights: • Hexamethyldisiloxane (HMDSO) films deposited by CVD on Si and Cu substrates • HMDSO films produced at the anode have greater content of organic SiO{sub 4} groups. • Films produced at the anode are harder than those deposited at the cathode. • HMDSO films produced at the cathode exhibited higher elastic recovery. • All films are hydrophobic (θ close to 100°)

Effect of self-bias voltage on the wettability, chemical functionality and nanomechanical properties of hexamethyldisiloxane films

International Nuclear Information System (INIS)

Albuquerque, M.D.F.; Santos, E.; Perdone, R.R.T.; Simao, R.A.

2014-01-01

Copper and silicon substrates were coated by chemical vapor deposition using hexamethyldisiloxane (HMDSO) as the precursor gas. Substrates were placed both at the anode and cathode of a glow discharge reactor, and films were deposited using different self-bias voltages. This study focuses on comparing the differences between the hydrophilicity, polymeric character, chemical structure and nanomechanical properties of HMDSO films produced at the cathode and anode of the reactor at different self-bias voltages. Fourier transform infrared spectroscopy and Raman confocal spectroscopy indicated a significant increase in the content of organic groups when films were deposited at the anode. Analyzing the nanomechanical properties of the cathode and anode films indicated that the penetration depth was higher for samples prepared at the cathode (lower hardness) compared with the samples produced at the anode. The measured contact angles indicated that all samples became hydrophobic with water contact angles close to 100°; however, a different lyophobic character was observed when diiodomethane was used. Films produced at the anode with diiodomethane exhibited higher contact angles than did films produced at the cathode. - Highlights: • Hexamethyldisiloxane (HMDSO) films deposited by CVD on Si and Cu substrates • HMDSO films produced at the anode have greater content of organic SiO 4 groups. • Films produced at the anode are harder than those deposited at the cathode. • HMDSO films produced at the cathode exhibited higher elastic recovery. • All films are hydrophobic (θ close to 100°)

Super high precision 200 ppi liquid crystal display series; Chokoseido 200 ppi ekisho display series

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

In mobile equipment, in demand is a high precision liquid crystal display (LCD) having the power of expression equivalent to printed materials like magazines because of the necessity of displaying a large amount of information on a easily potable small screen. In addition, with the spread and high-quality image of digital still cameras, it is strongly desired to display photographed digital image data in high quality. Toshiba Corp., by low temperature polysilicone (p-Si) technology, commercialized the liquid crystal display series of 200 ppi (pixels per inch) precision dealing with the rise of the high-precision high-image quality LCD market. The super high precision of 200 ppi enables the display of smooth beautiful animation comparable to printed sheets of magazines and photographs. The display series are suitable for the display of various information services such as electronic books and electronic photo-viewers including internet. The screen sizes lined up are No. 4 type VGA (640x480 pixels) of a small pocket notebook size and No. 6.3 type XGA (1,024x768 pixels) of a paperback size, with a larger screen to be furthered. (translated by NEDO)

Lithium secondary batteries: Role of polymer cathode morphology

Science.gov (United States)

Naoi, Katsuhiko; Osaka, Tetsuya; Owens, Boone B.

1988-06-01

Electrically conducting polymers have been utilized both as the cathode and as the electrolyte element of Li secondary cells. Polymer cathodes were limited in their suitability for batteries because of the low energy content associated with low levels of doping and the inclusion of complex ionic species in the cathode. Recent studies have indicated that doping levels up to 100 percent can be achieved in polyanilene. High doping levels in combination with controlled morphologies have been found to improve the energy and rate capabilities of polymer cathodes. A morphology-modifying technique was utilized to enhance the charge/discharge characteristics of Li/liquid electrolyte polypyrrole cells. The polymer is electropolymerized in a preferred orientation morphology when the substrate is first precoated with an insulating film of nitrile butadiene rubber (NBR). Modification of the kinetic behavior of the electrode results from variations in the chemical composition of the NBR.

Deposition of hematite Fe.sub.2./sub.O.sub.3./sub. thin film by DC pulsed magnetron and DC pulsed hollow cathode sputtering system

Czech Academy of Sciences Publication Activity Database

Hubička, Zdeněk; Kment, Štěpán; Olejníček, Jiří; Čada, Martin; Kubart, T.; Brunclíková, Michaela; Kšírová, Petra; Adámek, Petr; Remeš, Zdeněk

2013-01-01

Roč. 549, Dec (2013), s. 184-191 ISSN 0040-6090 R&D Projects: GA ČR GAP108/12/2104; GA MŠk LH12043 Grant - others:AVČR(CZ) M100101215 Institutional support: RVO:68378271 Keywords : HIPIMS * thin films * hollow cathode Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.867, year: 2013

Dendritic Ni(Cu)-polypyrrole hybrid films for a pseudo-capacitor.

Science.gov (United States)

Choi, Bit Na; Chun, Woo Won; Qian, Aniu; Lee, So Jeong; Chung, Chan-Hwa

2015-11-28

Dendritic Ni(Cu)-polypyrrole hybrid films are fabricated for a pseudo-capacitor in a unique morphology using two simple methods: electro-deposition and electrochemical de-alloying. Three-dimensional structures of porous dendrites are prepared by electro-deposition within the hydrogen evolution reaction (HER) at a high cathodic potential; the high-surface-area structure provides sufficient redox reactions between the electrodes and the electrolyte. The dependence of the active-layer thickness on the super-capacitor performance is also investigated, and the 60 μm-thick Ni(Cu)PPy hybrid electrode presents the highest performance of 659.52 F g(-1) at the scan rate of 5 mV s(-1). In the thicker layers, the specific capacitance became smaller due to the diffusion limitation of the ions in an electrolyte. The polypyrrole-hybridization on the porous dendritic Ni(Cu) electrode provides superior specific capacitance and excellent cycling stability due to the improvement in electric conductivity by the addition of conducting polypyrrole in the matrices of the dendritic nano-porous Ni(Cu) layer and the synergistic effect of composite materials.

Easily fabricated and lightweight PPy/PDA/AgNW composites for excellent electromagnetic interference shielding.

Science.gov (United States)

Wang, Yan; Gu, Fu-Qiang; Ni, Li-Juan; Liang, Kun; Marcus, Kyle; Liu, Shu-Li; Yang, Fan; Chen, Jin-Ju; Feng, Zhe-Sheng

2017-11-30

Conductive polymer composites (CPCs) containing nanoscale conductive fillers have been widely studied for their potential use in various applications. In this paper, polypyrrole (PPy)/polydopamine (PDA)/silver nanowire (AgNW) composites with high electromagnetic interference (EMI) shielding performance, good adhesion ability and light weight are successfully fabricated via a simple in situ polymerization method followed by a mixture process. Benefiting from the intrinsic adhesion properties of PDA, the adhesion ability and mechanical properties of the PPy/PDA/AgNW composites are significantly improved. The incorporation of AgNWs endows the functionalized PPy with tunable electrical conductivity and enhanced EMI shielding effectiveness (SE). By adjusting the AgNW loading degree in the PPy/PDA/AgNW composites from 0 to 50 wt%, the electrical conductivity of the composites greatly increases from 0.01 to 1206.72 S cm -1 , and the EMI SE of the composites changes from 6.5 to 48.4 dB accordingly (8.0-12.0 GHz, X-band). Moreover, due to the extremely low density of PPy, the PPy/PDA/AgNW (20 wt%) composites show a superior light weight of 0.28 g cm -3 . In general, it can be concluded that the PPy/PDA/AgNW composites with tunable electrical conductivity, good adhesion properties and light weight can be used as excellent EMI shielding materials.

Growth feature of ionic nitrogen doped CN_x bilayer films with Ti and TiN interlayer by pulse cathode arc discharge

International Nuclear Information System (INIS)

Zhou, Bing; Liu, Zhubo; Piliptsou, D.G.; Rogachev, A.V.; Yu, Shengwang; Wu, Yanxia; Tang, Bin; Rudenkov, A.S.

2016-01-01

Graphical abstract: - Highlights: • Ti/ and TiN/CN_x (N"+) bilayers are prepared at various frequencies by pulse cathode arc. • Ti interlayer facilitates the introduction of N atoms into the CN_x (N"+) films. • The most N-sp"2C bonds (mainly graphite-like N) present in the TiN/CN_x (N"+, 3 Hz) film. • Ti/CN_x (N"+, 3 Hz) bilayer possesses small size and disordering of Csp"2 clusters. • The higher hardness and the lower stress presents in the TiN/CN_x (N"+, 10 Hz) bilayer. - Abstract: Using nano-scaled Ti and TiN as interlayer, ionic nitrogen doped carbon (CN_x (N"+)) bilayer films were prepared at various pulse frequencies by cathode arc technique. Elemental distribution at the interface, bonding compositions, microstructure, and mechanical properties of CN_x (N"+) bilayer films were investigated in dependence of interlayer and pulse frequency by Auger electron spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, nanoindentation, and surface profilometer. The results showed that the diffusion extent of C atoms at the interface of CN_x (N"+) bilayers is higher than for the α-C and CN_x (N_2) bilayers with the same interlayer. Nitrogen atoms could diffuse throughout the pre-deposited Ti and TiN layers into the Si substrate for all CN_x (N"+) bilayers. Ti interlayer facilitates the introduction of N atoms into the CN_x (N"+) films and exhibits a certain catalytic effect on the coordination of N atoms with sp"2- and sp"3-C binding. More nitrogenated and intense CN bonding configurations (mainly graphite-like N) form in the TiN/CN_x (N"+) bilayer. Ti/CN_x (N"+) bilayer prepared at low frequency possesses small size and disordering of Csp"2 clusters but TiN interlayer weakens the formation of Csp"2 bonding and increases the disordering of Csp"2 clusters in the films. The residual stress in the bilayer is lower than for CN_x (N"+) monolayer. The higher hardness and the lower residual stress are present in the TiN/CN_x (N"+, 10 Hz) bilayer.

TiN thin film deposition by cathodic cage discharge: effect of cage configuration and active species

International Nuclear Information System (INIS)

De Freitas Daudt, N; Cavalcante Braz, D; Alves Junior, C; Pereira Barbosa, J C; Barbalho Pereira, M

2012-01-01

Plasma cathodic cage technique was developed recently in order to eliminate phenomena such as edge effects and overheating, which occur during conventional nitriding processes. In this work, the effect of plasma active species and cage configurations during thin film deposition of TiN were studied. This compound was chosen because its properties are very sensitive to slight variations in chemical composition and film thickness, becoming a good monitoring tool in fabrication process control. In order to verify the effect of cage geometry on the discharge and characteristics of the grown film, a cage made of titanium was used with different numbers and distribution of holes. Furthermore, different amounts of hydrogen were added to the Ar + N2 plasma atmosphere. Flow rates of Ar and N2 gas were fixed at 4 and 3 sccm, respectively and flow rates of H 2 gas was 0, 1 and 2 sccm. Plasma species, electrical discharge and physical characteristics of the grown film were analyzed by Optical Emission Spectroscopy (OES), Atomic Force Microscopy (AFM), X-Ray Diffraction. It was observed by OES that the luminous intensity associated to Hα species is not proportional to flow rate of H 2 gas. Electrical efficiency of the system, crystal structure and topography of the TiN film are strongly influenced by this behavior. For constant flow rate of H 2 gas, it was found that with more holes at the top of the cage, deposition rate, crystallinity and roughness are higher, if compared to cages with a small number of holes at the top of cage. On the other hand, the opposite behavior was observed when more holes were located at the sidewall of cage.

Diagnostic of a Hollow Cathode Radio-Frequency Plasma Excited in Organosilicon HMDSO, used for Barrier Anti Corrosion Thin Films Deposition

International Nuclear Information System (INIS)

Saloum, S.; Naddaf, M.

2010-01-01

In this work, remote hollow cathode RF plasma, generated from the monomer hexamethyledisiloxane (HMDSO), as a precursor, and argon as a feed gas, and the plasma mixture HMDSO/O 2 have been studied, as a function of different plasma parameters such as: RF applied power (100-300 W), HMDSO flow rate (2-32 sccm), time deposition (5-20 minutes), and oxygen fraction in HMDSO/O 2 mixture (0-0.9). Plasma diagnostic and prepared thin films characterization have been investigated. (author)

Surface functionalisation of polypyrrole films using UV light induced radical activation

International Nuclear Information System (INIS)

Lisboa, P.; Gilliland, D.; Ceccone, G.; Valsesia, A.; Rossi, F.

2006-01-01

Electrochemically deposited polypyrrole (PPy) films were functionalised with amine or carboxylic function. The functionalisation was done by grafting allylamine or acrylic acid (AAc) using UV light radical activation. The active groups of the surface were quantified by X-ray photoelectron spectroscopy (XPS) after chemical derivatisation with trifluoroethanol (TFE) or 4-trifluoromethylbenzaldehyde (TFBA), respectively. Grafting with AAc completely covered the PPy film introducing high levels of carboxylic function. In the case of allylamine grafting, a saturation point at low amine carbon level was achieved. Further characterisation of the surfaces was done by time of flight secondary ion mass spectroscopy (TOF-SIMS), atomic force microscope (AFM) and scanning electron microscope (SEM)

The Development of Non-Enzymatic Glucose Biosensors Based on Electrochemically Prepared Polypyrrole–Chitosan–Titanium Dioxide Nanocomposite Films

Directory of Open Access Journals (Sweden)

Ali M. A. Abdul Amir AL-Mokaram

2017-05-01

Full Text Available The performance of a modified electrode of nanocomposite films consisting of polypyrrole–chitosan–titanium dioxide (Ppy-CS-TiO2 has been explored for the developing a non-enzymatic glucose biosensors. The synergy effect of TiO2 nanoparticles (NPs and conducting polymer on the current responses of the electrode resulted in greater sensitivity. The incorporation of TiO2 NPs in the nanocomposite films was confirmed by X-ray photoelectron spectroscopy (XPS spectra. FE-SEM and HR-TEM provided more evidence for the presence of TiO2 in the Ppy-CS structure. Glucose biosensing properties were determined by amperommetry and cyclic voltammetry (CV. The interfacial properties of nanocomposite electrodes were studied by electrochemical impedance spectroscopy (EIS. The developed biosensors showed good sensitivity over a linear range of 1–14 mM with a detection limit of 614 μM for glucose. The modified electrode with Ppy-CS nanocomposite also exhibited good selectivity and long-term stability with no interference effect. The Ppy-CS-TiO2 nanocomposites films presented high electron transfer kinetics. This work shows the role of nanomaterials in electrochemical biosensors and describes the process of their homogeneous distribution in composite films by a one-step electrochemical process, where all components are taken in a single solution in the electrochemical cell.

Reactive-environment, hollow cathode sputtering: Basic characteristics and application to Al2O3, doped ZnO, and In2O3:Mo

International Nuclear Information System (INIS)

Delahoy, A.E.; Guo, S.Y.; Paduraru, C.; Belkind, A.

2004-01-01

A method for thin-film deposition has been studied. The method is based on metal sputtering in a hollow cathode configuration with supply of a reactive gas in the vicinity of the substrate. The working gas and entrained sputtered atoms exit the cathode through an elongated slot. The reactive gas is thereby largely prevented from reaching the target. The basic operation of the cathode was studied using a Cu target and pulsed power excitation. These studies included the dependence of deposition rate on power, pressure, and flow rate, film thickness profiles, and film resistivity as a function of substrate conditions. Modeling was conducted to calculate the gas velocity distribution and pressure inside the cavity. Al 2 O 3 films were prepared in a reactive environment of oxygen by sputtering an Al target. It was demonstrated that only a very small amount of oxygen passing through the cathode will oxidize (poison) the target, whereas large quantities of oxygen supplied externally to the cathode need not affect the target at all. A very stable discharge and ease of Al 2 O 3 formation were realized in this latter mode. The method was applied to the preparation of transparent, conductive films of ZnO doped with either Al or B. High deposition rates were achieved, and, at appropriate oxygen flow rates, low film resistivities. High-mobility In 2 O 3 :Mo transparent conductors were also prepared, with resistivities as low as 1.9x10 -4 Ω cm. Scaling relations for hollow cathodes, and deposition efficiency, and process comparisons between magnetron sputtering and linear, reactive-environment, hollow cathode sputtering are presented

Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

Energy Technology Data Exchange (ETDEWEB)

Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

2016-03-31

cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions has been studied. It is found that SrO readily segregated/enriched on the LSCF surface. More severe contamination conditions cause more SrO on surface. Novel catalyst coatings through particle depositions (PrOx) or continuous thin films (PNM) were successfully developed to improve the activity and stability of LSCF cathodes. Finally, we have demonstrated enhanced activity and stability of LSCF cathodes over longer periods of time in homemade and commercially available cells by an optimized PNM (dense film and particles) infiltration process, under clean air and realistic operating conditions (3% H₂O, 5% CO₂ and direct Crofer contact). Both performance and durability of single cells with PNM coating has been enhanced compared with those without coating. Raman analysis of cathodes surface indicated that the intensity of SrCrO₄ was significantly decreased.

A nano-graphite cold cathode for an energy-efficient cathodoluminescent light source

Directory of Open Access Journals (Sweden)

Alexander N. Obraztsov

2013-08-01

Full Text Available The development of new types of light sources is necessary in order to meet the growing demands of consumers and to ensure an efficient use of energy. The cathodoluminescence process is still under-exploited for light generation because of the lack of cathodes suitable for the energy-efficient production of electron beams and appropriate phosphor materials. In this paper we propose a nano-graphite film material as a highly efficient cold cathode, which is able to produce high intensity electron beams without energy consumption. The nano-graphite film material was produced by using chemical vapor deposition techniques. Prototypes of cathodoluminescent lamp devices with a construction optimized for the usage of nano-graphite cold cathodes were developed, manufactured and tested. The results indicate prospective advantages of this type of lamp and the possibility to provide advanced power efficiency as well as enhanced spectral and other characteristics.

Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

International Nuclear Information System (INIS)

Kumar, Vijay; Ali, Yasir; Sharma, Kashma; Kumar, Vinod; Sonkawade, R.G.; Dhaliwal, A.S.; Swart, H.C.

2014-01-01

Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li 3+ ion beam irradiation for various fluences (1 × 10 11 , 1 × 10 12 and 1 × 10 13 ions/cm 2 ). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence

Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

Energy Technology Data Exchange (ETDEWEB)

Kumar, Vijay, E-mail: vijays_phy@rediffmail.com [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Ali, Yasir [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Sharma, Kashma [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Department of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan 173212 (India); Kumar, Vinod [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Sonkawade, R.G. [Inter University Accelerator Center, Aruna Asif Ali Marg, New Delhi 110067 (India); Dhaliwal, A.S. [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa)

2014-03-15

Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li{sup 3+} ion beam irradiation for various fluences (1 × 10{sup 11}, 1 × 10{sup 12} and 1 × 10{sup 13} ions/cm{sup 2}). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence.

Safety of long-term PPI therapy

DEFF Research Database (Denmark)

Reimer, Christina

2013-01-01

Proton pump inhibitors have become the mainstay of medical treatment of acid-related disorders. Long-term use is becoming increasingly common, in some cases without a proper indication. A large number of mainly observational studies on a very wide range of possible associations have been publishe...... to a careful evaluation of the indication for PPI treatment....

Effect of anionic dopants on thickness, morphology and electrical properties of polypyrrole ultra-thin films prepared by in situ chemical polymerization

Energy Technology Data Exchange (ETDEWEB)

Mahmoodian, Mehrnoosh [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Pourabbas, Behzad, E-mail: pourabas@sut.ac.ir [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Mohajerzadeh, Shams [Nano-Electronics and Thin Film Lab, School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran (Iran, Islamic Republic of)

2015-05-29

The effect of different dopant anions on deposition and characteristics of polypyrrole (PPy) thin film has been studied in this work. Ultra-thin films of conducting PPy were deposited on insulating surfaces of glass and oxidized silicon wafer by in situ chemical polymerization in the presence of different anionic dopants including sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, α-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate, and camphor sulfonic acid. Hydrophilic/hydrophobic properties and morphology of the self-assembled monolayer of N-(3-trimethoxysilylpropyl)pyrrole, the surface modifying agent in this work, and PPy thin films were characterized before and after deposition by contact angle measurements, field emission scanning electron microscopy, and atomic force microscopy. Chemical structure, thickness, and conductivity of the thin films were also studied by attenuated total reflectance Fourier transform infrared spectrometer, ellipsometry, and four-point probe measurements. The results showed deposition of thin films of conducting PPy with comparable thickness in the range of 6-31 nm and different morphologies, uniformity, and smoothness with average roughness in the range of 0.3-6 nm and relatively high range of conductivity on the modified surfaces. - Highlights: • Conducting thin films of polypyrrole were deposited on glass and SiO{sub 2} substrates. • Surface modification using pyrrole-silane was employed prior to polymerization. • Films as thin as ≈ 7 nm were deposited using different surfactant/counter ions. • Chemistry of the counter ion affects thickness, conductivity and morphology. • Lower thickness/higher conductivity were obtained by structurally flexible dopants.

Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

International Nuclear Information System (INIS)

Feng, Xiaojuan; Shi, Yanlong; Jin, Shuping

2015-01-01

The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g"−"1 at 0.3 A g"−"1 current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g"−"1), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

Energy Technology Data Exchange (ETDEWEB)

Feng, Xiaojuan, E-mail: cherry-820@163.com; Shi, Yanlong; Jin, Shuping

2015-10-30

The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g{sup −1} at 0.3 A g{sup −1} current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g{sup −1}), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation

OpenAIRE

Schroeder, Jeremy; Thomson, W.; Howard, B.; Schell, N.; Näslund, Lars-Åke; Rogström, Lina; Johansson-Jöesaar, Mats P.; Ghafoor, Naureen; Odén, Magnus; Nothnagel, E.; Shepard, A.; Greer, J.; Birch, Jens

2015-01-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation...

Investigations Of A Pulsed Cathodic Vacuum Arc

Science.gov (United States)

Oates, T. W. H.; Pigott, J.; Denniss, P.; Mckenzie, D. R.; Bilek, M. M. M.

2003-06-01

Cathodic vacuum arcs are well established as a method for producing thin films for coatings and as a source of metal ions. Research into DC vacuum arcs has been going on for over ten years in the School of Physics at the University of Sydney. Recently a project was undertaken in the school to design and build a pulsed CVA for use in the investigation of plasma sheaths and plasma immersion ion implantation. Pulsed cathodic vacuum arcs generally have a higher current and plasma density and also provide a more stable and reproducible plasma density than their DC counterparts. Additionally it has been shown that if a high repetition frequency can be established the deposition rate of pulsed arcs is equal to or greater than that of DC arcs with a concomitant reduction in the rate of macro-particle formation. We present here results of our investigations into the building of a center-triggered pulsed cathodic vacuum arc. The design of the power supply and trigger mechanism and the geometry of the anode and cathode are examined. Observations of type I and II arc spots using a CCD camera, and cathode spot velocity dependence on arc current will be presented. The role of retrograde motion in a high current pulsed arc is discussed.

Investigations Of A Pulsed Cathodic Vacuum Arc

International Nuclear Information System (INIS)

Oates, T.W.H.; Pigott, J.; Denniss, P.; Mckenzie, D.R.; Bilek, M.M.M.

2003-01-01

Cathodic vacuum arcs are well established as a method for producing thin films for coatings and as a source of metal ions. Research into DC vacuum arcs has been going on for over ten years in the School of Physics at the University of Sydney. Recently a project was undertaken in the school to design and build a pulsed CVA for use in the investigation of plasma sheaths and plasma immersion ion implantation. Pulsed cathodic vacuum arcs generally have a higher current and plasma density and also provide a more stable and reproducible plasma density than their DC counterparts. Additionally it has been shown that if a high repetition frequency can be established the deposition rate of pulsed arcs is equal to or greater than that of DC arcs with a concomitant reduction in the rate of macro-particle formation. We present here results of our investigations into the building of a center-triggered pulsed cathodic vacuum arc. The design of the power supply and trigger mechanism and the geometry of the anode and cathode are examined. Observations of type I and II arc spots using a CCD camera, and cathode spot velocity dependence on arc current will be presented. The role of retrograde motion in a high current pulsed arc is discussed

Improved stability of organic light-emitting diode with aluminum cathodes prepared by ion beam assisted deposition

Directory of Open Access Journals (Sweden)

Soon Moon Jeong, Deuk Yeon Lee, Won Hoe Koo, Sang Hun Choi, Hong Koo Baik, Se-Jong Lee and Kie Moon Song

2005-01-01

Full Text Available We have fabricated highly stable organic electroluminescent devices based on spin-coated poly-p-phenylene-vynylene (PPV thin films. The electrical properties of aluminum cathode, prepared by ion beam assisted deposition, on PPV have been investigated and compared to those by thermal evaporation. Although energetic particles of Al assisted by Ar+ ion may damage the organic material, I–V–L characteristics are improved by applying thin Al buffer layer. In addition, a dense Al cathode inhibits the permeation of H2O and O2 into PPV film through pinhole defects, and thus retards dark spot growth. It may be deduced from highly packed structure of Al cathode with an increase in the contact area between Al and PPV that reduce the contact resistance. In conclusion, the lifetime of organic light-emitting device (OLED has been extended effectively by dense Al film through ion beam assisted deposition process.

Solid oxide fuel cell cathode with oxygen-reducing layer

Science.gov (United States)

Surdoval, Wayne A.; Berry, David A.; Shultz, Travis

2018-04-03

The disclosure provides a SOFC comprised of an electrolyte, anode, and cathode, where the cathode comprises an MIEC and an oxygen-reducing layer. The oxygen-reducing layer is in contact with the MIEC, and the MIEC is generally between and separating the oxygen-reducing layer and the electrolyte. The oxygen-reducing layer is comprised of single element oxides, single element carbonates, or mixtures thereof, and has a thickness of less than about 30 nm. In a particular embodiment, the thickness is less than 5 nm. In another embodiment, the thickness is about 3 monolayers or less. The oxygen-reducing layer may be a continuous film or a discontinuous film with various coverage ratios. The oxygen-reducing layer at the thicknesses described may be generated on the MIEC surface using means known in the art such as, for example, ALD processes.

Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia

International Nuclear Information System (INIS)

Chiba, Rubens

2010-01-01

The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 μm of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

Design of an oval-form cathode for the precision etching process of e-paper surface

International Nuclear Information System (INIS)

Pa, P.S.

2009-01-01

A newly designed oval-form cathode using electroetching for indium-tin-oxide (ITO) microstructure removal from the surface of e-paper polymer PET films is presented. Through ultra-precise microstructural etching, the semiconductor industry can effectively reclaim defective products, thereby reducing production costs. The design features for the ITO removal process and the tool design of oval-form cathodes are of significant interest. A smaller oval-form cathode minor axis, a higher cathode rotational speed, a higher concentration, or a higher electrolyte temperature corresponds to a higher ITO etching rate.

Effect of modulation periods on the microstructure and mechanical properties of DLC/TiC multilayer films deposited by filtered cathodic vacuum arc method

International Nuclear Information System (INIS)

Xu, Zhaoying; Sun, H.; Leng, Y.X.; Li, Xueyuan; Yang, Wenmao; Huang, N.

2015-01-01

Highlights: • DLC/TiC multilayer films with different modulation periods at same modulation ratio 1:1 were deposited by FCVA. • The residual stress of DLC/TiC multilayer films decreases with the modulation periods decrease. • The hardness of the multilayer DLC films decreases with modulation periods increasing. - Abstract: The high stress of diamond-like carbon (DLC) film limits its thickness and adhesion on substrate. Multilayer structure is one approach to overcome this disadvantage. In this paper, the DLC/TiC multilayer films with different modulation periods (80 nm, 106 nm or 160 nm) at same modulation ratio of 1:1 were deposited on Si(1 0 0) wafer and Ti-6Al-4V substrate by filtered cathodic vacuum arc (FCVA) technology. X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoindention and wear test were employed to investigate the effect of modulation periods on the microstructure and mechanical properties of the multilayer films. The results showed that the residual stress of the DLC/TiC multilayer films could be effectively reduced and the residual stress decreased with the modulation periods decreasing. The hardness of the DLC/TiC multilayer films increased with modulation periods decreasing. The DLC/TiC multilayer film with modulation period of 106 nm had the best wear resistance due to the good combination of hardness, ductility and low compressive stress

QE data for Pb/Nb deposited photo cathode samples

CERN Document Server

Sekutowicz, J

2010-01-01

This report outlines progress in the development of photo-cathodes for a hybrid lead/niobium (Pb/Nb) superconducting SRF electron injector. We have coated eight Nb samples with lead to study and determine deposition conditions leading to high quality emitting area. The results show that the oxide layer significantly influences the quantum efficiency (QE) of all measured cathodes. In addition, we learned that although the laser cleaning enhanced the QE substantially, the film morphology was strongly modified. That observation convinced us to make the coatings thicker and therefore more robust.

Feasibility of MR Imaging/MR Spectroscopy-Planned Focal Partial Salvage Permanent Prostate Implant (PPI) for Localized Recurrence After Initial PPI for Prostate Cancer

International Nuclear Information System (INIS)

Hsu, Charles C.; Hsu, Howard; Pickett, Barby; Crehange, Gilles; Hsu, I-Chow Joe; Dea, Ryan; Weinberg, Vivian; Gottschalk, Alexander R.; Kurhanewicz, John; Shinohara, Katsuto; Roach, Mack

2013-01-01

Purpose: To assess the feasibility of magnetic resonance imaging (MRI)-planned partial salvage permanent prostate implant (psPPI) among patients with biopsy-proven local recurrence after initial PPI without evidence of distant disease. Methods and Materials: From 2003-2009, 15 patients underwent MRI/magnetic resonance spectroscopy (MRS) planning for salvage brachytherapy (psPPI, I-125 [n=14; 144 Gy]; Pd-103 [n=1; 125 Gy]) without hormone therapy. Full dose was prescribed to areas of recurrence and underdosage, without entire prostate implantation. Limiting urethral and rectal toxicity was prioritized. Follow-up was from salvage date to prostate-specific antigen (PSA) concentration failure (Phoenix criteria = nadir + 2.0; ASTRO = 3 consecutive rises), recurrence, distant metastases, or last follow-up PSA level. Progression-free survival (PFS) was defined as no PSA failure or biopsy-proven recurrence without all-cause mortality. Toxicity was scored using Common Terminology Criteria for Adverse Events version 4.0. Results: At salvage, median age was 68 years, and PSA concentration was 3.5 ng/mL (range, 0.9-5.6 ng/mL). Abnormal MRI/MRS findings were evident in 40% of patients. Biopsy-proven recurrences consisted of a single focus (80%) or 2 foci (20%). At recurrence, Gleason score was 6 (67%) or ≥7 (27%). Median interval between initial and salvage implantation was 69 months (range, 28-132 months). psPPI planning characteristics limited doses to the rectum (mean V100 = 0.5% [0.07 cc]) and urethra (V100 = 12% [0.3 cc]). At median follow-up (23.3 months; range, 8-88 months), treatment failure (n=2) resulted only in localized recurrence; both patients underwent second psPPI with follow-up PSA tests at 12 and 26 months, resulting in 0.6 and 0.7 ng/mL, respectively. American Society for Radiation Oncology PFS rates at 1, 2, and 3 years were 86.7%, 78.4%, and 62.7%, respectively, with 5 patients for whom treatment failed (n=3 with negative transrectal ultrasound

Feasibility of MR Imaging/MR Spectroscopy-Planned Focal Partial Salvage Permanent Prostate Implant (PPI) for Localized Recurrence After Initial PPI for Prostate Cancer

Energy Technology Data Exchange (ETDEWEB)

Hsu, Charles C., E-mail: hsucc@radonc.ucsf.edu [Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Hsu, Howard [Department of Radiation Oncology, New York University, New York, New York (United States); Pickett, Barby [Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Crehange, Gilles [Department of Radiation Oncology, Dijon University, Dijon (France); Hsu, I-Chow Joe; Dea, Ryan [Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Weinberg, Vivian [Biostatistics and Computational Biology Core, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Gottschalk, Alexander R. [Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Kurhanewicz, John [Department of Radiology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Shinohara, Katsuto [Department of Urology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States); Roach, Mack [Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California (United States)

2013-02-01

Purpose: To assess the feasibility of magnetic resonance imaging (MRI)-planned partial salvage permanent prostate implant (psPPI) among patients with biopsy-proven local recurrence after initial PPI without evidence of distant disease. Methods and Materials: From 2003-2009, 15 patients underwent MRI/magnetic resonance spectroscopy (MRS) planning for salvage brachytherapy (psPPI, I-125 [n=14; 144 Gy]; Pd-103 [n=1; 125 Gy]) without hormone therapy. Full dose was prescribed to areas of recurrence and underdosage, without entire prostate implantation. Limiting urethral and rectal toxicity was prioritized. Follow-up was from salvage date to prostate-specific antigen (PSA) concentration failure (Phoenix criteria = nadir + 2.0; ASTRO = 3 consecutive rises), recurrence, distant metastases, or last follow-up PSA level. Progression-free survival (PFS) was defined as no PSA failure or biopsy-proven recurrence without all-cause mortality. Toxicity was scored using Common Terminology Criteria for Adverse Events version 4.0. Results: At salvage, median age was 68 years, and PSA concentration was 3.5 ng/mL (range, 0.9-5.6 ng/mL). Abnormal MRI/MRS findings were evident in 40% of patients. Biopsy-proven recurrences consisted of a single focus (80%) or 2 foci (20%). At recurrence, Gleason score was 6 (67%) or {>=}7 (27%). Median interval between initial and salvage implantation was 69 months (range, 28-132 months). psPPI planning characteristics limited doses to the rectum (mean V100 = 0.5% [0.07 cc]) and urethra (V100 = 12% [0.3 cc]). At median follow-up (23.3 months; range, 8-88 months), treatment failure (n=2) resulted only in localized recurrence; both patients underwent second psPPI with follow-up PSA tests at 12 and 26 months, resulting in 0.6 and 0.7 ng/mL, respectively. American Society for Radiation Oncology PFS rates at 1, 2, and 3 years were 86.7%, 78.4%, and 62.7%, respectively, with 5 patients for whom treatment failed (n=3 with negative transrectal ultrasound

A patient and public involvement (PPI) toolkit for meaningful and flexible involvement in clinical trials - a work in progress.

Science.gov (United States)

Bagley, Heather J; Short, Hannah; Harman, Nicola L; Hickey, Helen R; Gamble, Carrol L; Woolfall, Kerry; Young, Bridget; Williamson, Paula R

2016-01-01

Funders of research are increasingly requiring researchers to involve patients and the public in their research. Patient and public involvement (PPI) in research can potentially help researchers make sure that the design of their research is relevant, that it is participant friendly and ethically sound. Using and sharing PPI resources can benefit those involved in undertaking PPI, but existing PPI resources are not used consistently and this can lead to duplication of effort. This paper describes how we are developing a toolkit to support clinical trials teams in a clinical trials unit. The toolkit will provide a key 'off the shelf' resource to support trial teams with limited resources, in undertaking PPI. Key activities in further developing and maintaining the toolkit are to: ● listen to the views and experience of both research teams and patient and public contributors who use the tools; ● modify the tools based on our experience of using them; ● identify the need for future tools; ● update the toolkit based on any newly identified resources that come to light; ● raise awareness of the toolkit and ● work in collaboration with others to either develop or test out PPI resources in order to reduce duplication of work in PPI. Background Patient and public involvement (PPI) in research is increasingly a funder requirement due to the potential benefits in the design of relevant, participant friendly, ethically sound research. The use and sharing of resources can benefit PPI, but available resources are not consistently used leading to duplication of effort. This paper describes a developing toolkit to support clinical trials teams to undertake effective and meaningful PPI. Methods The first phase in developing the toolkit was to describe which PPI activities should be considered in the pathway of a clinical trial and at what stage these activities should take place. This pathway was informed through review of the type and timing of PPI activities within

Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

International Nuclear Information System (INIS)

Kim, Hyo-Joong; Kim, Han-Ki; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok

2015-01-01

The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs

Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyo-Joong; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Lee, Hyun Hwi [Pohang Accelerator Laboratory, POSTECH, Jigokro-127beon-gil, Nam-gu, Pohang 790-784 (Korea, Republic of); Kal, Jinha; Hahn, Jungseok [Future Technology Research Group, Kolon Central Research Park, 154 Mabukro, Giheung-ku, Yongin-si, Kyunggi-do, 16910 (Korea, Republic of)

2015-10-15

The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

The influence of monomer concentration on the optical properties of electrochemically synthesized polypyrrole thin films

International Nuclear Information System (INIS)

Thombare, J. V.; Fulari, V. J.; Rath, M. C.; Han, S. H.

2013-01-01

Polypyrrole (PPy) thin films were deposited on stainless steel and ITO coated glass substrate at a constant deposition potential of 0.8 V versus saturated calomel electrode (SCE) by using the electrochemical polymerization method. The PPy thin films were deposited at room temperature at various monomer concentrations ranging from 0.1 M to 0.3 M pyrrole. The structural and optical properties of the polypyrrole thin films were investigated using an X-ray diffractometer (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), and ultraviolet—visible (UV—vis) spectroscopy. The XRD results show that polypyrrole thin films have a semi crystalline structure. Higher monomer concentration results in a slight increase of crystallinity. The polypyrrole thin films deposited at higher monomer concentration exhibit high visible absorbance. The refractive indexes of the polypyrrole thin films are found to be in the range of 1 to 1.3 and vary with monomer concentration as well as wavelength. The extinction coefficient decreases slightly with monomer concentration. The electrochemically synthesized polypyrrole thin film shows optical band gap energy of 2.14 eV. (semiconductor materials)

MEMS sensor material based on polypyrrole carbon nanotube nanocomposite: film deposition and characterization

Science.gov (United States)

Teh, Kwok-Siong; Lin, Liwei

2005-11-01

Conductive polymer-based nanocomposite has been utilized as a MEMS sensing material via a one-step, selective on-chip deposition process at room temperature. A doped polypyrrole (PPy) variant synthesized by incorporating multi-walled carbon nanotube (MWCNT) into electropolymerized PPy has been shown to improve the sensing performance utilizing a two-terminal, micro-gap chemiresistor architecture. The dodecylbenzenesulfonate (DBS)-doped PPy-MWCNT nanocomposites are found to be responsive to oxidants, such as hydrogen peroxide (H2O2), and this effect can be extended to glucose detection using H2O2 as a proxy material. The oxidant sensing effect is demonstrated by subjecting a glucose oxidase (GOx)-laden PPy-MWCNT nanocomposite film to various concentrations of glucose solution. Such PPy-MWCNT nanocomposite, when applied in a chemiresistor configuration, obviates the need for reference electrode and electron mediators, by measuring the direct and reversible, oxidation-reduction induced conductivity change. Experimentally, GOx-laden, doped PPy-MWCNT is tested to be sensitive to glucose concentration up to 20 mM, which covers the physiologically important range for diabetics of 0-20 mM.

New secondary batteries utilizing electronically conductive polymer cathodes

Science.gov (United States)

Martin, Charles R.; White, Ralph E.

1989-01-01

The objectives of this project are to characterize the transport properties in electronically conductive polymers and to assess the utility of these films as cathodes in lithium/polymer secondary batteries. During this research period, progress has been made in a literature survey of the historical background, methods of preparation, the physical and chemical properties, and potential technological applications of polythiophene. Progress has also been made in the characterization of polypyrrole flat films and fibrillar films. Cyclic voltammetry and potential step chronocoulometry were used to gain information on peak currents and potentials switching reaction rates, charge capacity, and charge retention. Battery charge/discharge studies were also performed.

Laser microstructuring and annealing processes for lithium manganese oxide cathodes

International Nuclear Information System (INIS)

Proell, J.; Kohler, R.; Torge, M.; Ulrich, S.; Ziebert, C.; Bruns, M.; Seifert, H.J.; Pfleging, W.

2011-01-01

It is expected that cathodes for lithium-ion batteries (LIB) composed out of nano-composite materials lead to an increase in power density of the LIB due to large electrochemically active surface areas but cathodes made of lithium manganese oxides (Li-Mn-O) suffer from structural instabilities due to their sensitivity to the average manganese oxidation state. Therefore, thin films in the Li-Mn-O system were synthesized by non-reactive radiofrequency magnetron sputtering of a spinel lithium manganese oxide target. For the enhancement of the power density and cycle stability, large area direct laser patterning using UV-laser radiation with a wavelength of 248 nm was performed. Subsequent laser annealing processes were investigated in a second step in order to set up a spinel-like phase using 940 nm laser radiation at a temperature of 680 deg. C. The interaction processes between UV-laser radiation and the material was investigated using laser ablation inductively coupled plasma mass spectroscopy. The changes in phase, structure and grain shape of the thin films due to the annealing process were recorded using Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The structured cathodes were cycled using standard electrolyte and a metallic lithium anode. Different surface structures were investigated and a significant increase in cycling stability was found. Surface chemistry of an as-deposited as well as an electrochemically cycled thin film was investigated via X-ray photoelectron spectroscopy.

A review on comparative study of PPI and PAMAM dendrimers

International Nuclear Information System (INIS)

Kaur, Daljeet; Jain, Keerti; Mehra, Neelesh Kumar; Kesharwani, Prashant; Jain, Narendra K.

2016-01-01

Dendrimers are hyperbranched, monodispersed macromolecules with multivalent functional end groups. Dendrimers have been explored as carrier for many drugs like anticancer, antiviral, antimalarial, antiprotozoal, anti tubercular drugs. Although a number of different types of dendrimers containing different core molecules, branching monomers and surface functional groups have been designed till date for drug delivery applications, yet the poly(propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers have been the most explored dendrimers in this regard. In this review, we have summarized a comparative data on PPI and PAMAM dendrimers particularly relevant to their properties, synthesis, toxicity, biomedical applications and drug delivery attributes.

A review on comparative study of PPI and PAMAM dendrimers

Energy Technology Data Exchange (ETDEWEB)

Kaur, Daljeet; Jain, Keerti, E-mail: keertijain02@gmail.com; Mehra, Neelesh Kumar [ISF College of Pharmacy, Pharmaceutical Nanotechnology Research Laboratory (India); Kesharwani, Prashant [Wayne State University, Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences (United States); Jain, Narendra K., E-mail: jnarendr@yahoo.co.in, E-mail: dr.jnarendr@gmail.com [ISF College of Pharmacy, Pharmaceutical Nanotechnology Research Laboratory (India)

2016-06-15

Dendrimers are hyperbranched, monodispersed macromolecules with multivalent functional end groups. Dendrimers have been explored as carrier for many drugs like anticancer, antiviral, antimalarial, antiprotozoal, anti tubercular drugs. Although a number of different types of dendrimers containing different core molecules, branching monomers and surface functional groups have been designed till date for drug delivery applications, yet the poly(propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers have been the most explored dendrimers in this regard. In this review, we have summarized a comparative data on PPI and PAMAM dendrimers particularly relevant to their properties, synthesis, toxicity, biomedical applications and drug delivery attributes.

Characterization of 12CaO x 7Al2O3 doped indium tin oxide films for transparent cathode in top-emission organic light-emitting diodes.

Science.gov (United States)

Jung, Chul Ho; Hwang, In Rok; Park, Bae Ho; Yoon, Dae Ho

2013-11-01

12CaO x 7Al2O3, insulator (C12A7) doped indium tin oxide (ITO) (ITO:C12A7) films were fabricated using a radio frequency magnetron co-sputtering system with ITO and C12A7 targets. The qualitative and quantitative properties of ITO:C12A7 films, as a function of C12A7 concentration, were examined via X-ray photoemission spectroscopy and synchrotron X-ray scattering as well as by conducting atomic force microscopy. The work function of ITO:C12A7 (1.3%) films of approximately 2.8 eV obtained by high resolution photoemission spectroscopy measurements make them a reasonable cathode for top-emission organic light-emitting diodes.

Comparison of trimethylgallium and triethylgallium as “Ga” source materials for the growth of ultrathin GaN films on Si (100) substrates via hollow-cathode plasma-assisted atomic layer deposition

International Nuclear Information System (INIS)

Alevli, Mustafa; Haider, Ali; Kizir, Seda; Leghari, Shahid A.; Biyikli, Necmi

2016-01-01

GaN films grown by hollow cathode plasma-assisted atomic layer deposition using trimethylgallium (TMG) and triethylgallium (TEG) as gallium precursors are compared. Optimized and saturated TMG/TEG pulse widths were used in order to study the effect of group-III precursors. The films were characterized by grazing incidence x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry. Refractive index follows the same trend of crystalline quality, mean grain, and crystallite sizes. GaN layers grown using TMG precursor exhibited improved structural and optical properties when compared to GaN films grown with TEG precursor

Comparison of trimethylgallium and triethylgallium as “Ga” source materials for the growth of ultrathin GaN films on Si (100) substrates via hollow-cathode plasma-assisted atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Alevli, Mustafa, E-mail: mustafaalevli@marmara.edu.tr [Department of Physics, Marmara University, Göztepe Kadıköy, 34722 İstanbul (Turkey); Haider, Ali; Kizir, Seda; Leghari, Shahid A.; Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr [Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara, Turkey and National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, 06800 Ankara (Turkey)

2016-01-15

GaN films grown by hollow cathode plasma-assisted atomic layer deposition using trimethylgallium (TMG) and triethylgallium (TEG) as gallium precursors are compared. Optimized and saturated TMG/TEG pulse widths were used in order to study the effect of group-III precursors. The films were characterized by grazing incidence x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry. Refractive index follows the same trend of crystalline quality, mean grain, and crystallite sizes. GaN layers grown using TMG precursor exhibited improved structural and optical properties when compared to GaN films grown with TEG precursor.

Polypyrrole-polyvinyl sulphonate film based disposable nucleic acid biosensor

Energy Technology Data Exchange (ETDEWEB)

Prabhakar, Nirmal [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Arora, Kavita [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Surinder P. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Pandey, Manoj K. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Harpal [Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Malhotra, Bansi D. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India)]. E-mail: bansi.malhotra@gmail.com

2007-04-18

Double stranded calf thymus deoxyribonucleic acid entrapped polypyrrole-polyvinyl sulphonate (dsCT-DNA-PPy-PVS) films fabricated onto indium-tin-oxide (ITO) coated glass plates have been used to detect organophosphates such as chlorpyrifos and malathion. These disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes have been characterized using cyclic voltammetry, Fourier-transform-infra-red (FTIR) spectroscopy and atomic force microscopy (AFM), respectively. These biosensing electrodes have a response time of 30 s, are stable for about 5 months when stored in desiccated conditions at 25 deg. C and can be used to amperometrically detect chlorpyrifos (0.0016-0.025 ppm) and malathion (0.17-5.0), respectively. The additive effect of these pesticides on the amperometric response of the disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes has also been investigated.

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

Science.gov (United States)

Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

2015-09-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument.

Synchrotron Investigations of SOFC Cathode Degradation

Energy Technology Data Exchange (ETDEWEB)

Idzerda, Yves

2013-09-30

The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-δ} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

Significant enhancement in volumetric and gravimetric capacitance of Cu-TiO2/PPY composite for supercapacitor application

Science.gov (United States)

Purty, B.; Choudhary, R. B.

2018-04-01

Copper doped titanium dioxide-polypyrrole (Cu-TiO2/PPY) composite was successfully synthesized via chemical oxidative in-situ polymerization process. The structural and morphological properties of Cu-TiO2/PPY composite were investigated using X-ray diffractometer (XRD), field emission electron microscopy (FESEM) and transmission electron microscopy(TEM) techniques. The electrochemical properties of as-synthesized composite were studied using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopic (EIS) techniques. The novel Cu-TiO2/PPY composite showed enhanced volumetric capacitance ˜714 F cm-1 and gravimetric capacitance ˜674 F g-1 at 1 A g-1. In addition an excellent coulombic efficiency and comparabley low charge transfer resistance than pure PPY suggests improved supercapacitive performance of Cu-TiO2/PPY composite as an electrode material.

Hierarchical polypyrrole based composites for high performance asymmetric supercapacitors

Science.gov (United States)

Chen, Gao-Feng; Liu, Zhao-Qing; Lin, Jia-Ming; Li, Nan; Su, Yu-Zhi

2015-06-01

An advanced asymmetric supercapacitor with high energy density, exploiting hierarchical polypyrrole (PPy) based composites as both the anode [three dimensional (3D) chuzzle-like Ni@PPy@MnO2] and (3D cochleate-like Ni@MnO2@PPy) cathode, has been developed. The ultrathin PPy and flower-like MnO2 orderly coating on the high-conductivity 3D-Ni enhance charge storage while the unique 3D chuzzle-like and 3D cochleate-like structures provide storage chambers and fast ion transport pathways for benefiting the transport of electrolyte ions. The 3D cochleate-like Ni@MnO2@PPy possesses excellent pseudocapacitance with a relatively negative voltage window while preserved EDLC and free transmission channels conducive to hold the high power, providing an ideal cathode for the asymmetric supercapacitor. It is the first report of assembling hierarchical PPy based composites as both the anode and cathode for asymmetric supercapacitor, which exhibits wide operation voltage of 1.3-1.5 V with maximum energy and power densities of 59.8 Wh kg-1 and 7500 W kg-1.

Analysis of the dopant distribution in Co-deposited organic thin films by scanning transmission electron microscopy

International Nuclear Information System (INIS)

Paredes, Yolanda A.; Campos, Andrea P.C.; Achete, Carlos A.; Cremona, Marco

2015-01-01

Organic light-emitting diodes using phosphorescent dyes (PHOLEDs) have excellent performance, with internal quantum efficiencies approaching 100%. To maximize their performance, PHOLED devices use a conductive organic host material with a sufficiently dispersed phosphorescent guest to avoid concentration quenching. Fac-tris(2-phenylpyridine) iridium, [Ir(ppy)_3] is one of the most widely used green phosphorescent organic compounds. In this work, we used scanning transmission electron microscopy (STEM) equipped with HAADF (high-angle annular dark-field) and EDS (energy dispersive X-ray spectroscopy) detectors to analyze the distribution of the [Ir(ppy)_3] concentration in the host material. This analysis technique, employed for the first time in co-deposited organic thin films, can simultaneously obtain an image and its respective chemical information, allowing for definitive characterization of the distribution and morphology of [Ir(ppy)_3]. The technique was also used to analyze the effect of the vibration of the substrate during thermal co-deposition of the [Ir(ppy)_3] molecules into an organic matrix. - Highlights: • We present a methodology to analyze the dopant distribution in organic thin films. • The method combines HAADF-STEM imaging and EDS X-ray spectroscopy. • Ir(ppy)_3 dopant was co-deposited into Spiro2-CBP organic matrix. • The dopant was co-deposited with and without substrate vibration. • Images and chemical information of the dopant were simultaneously obtained.

Nitrogen doping for adhesion improvement of DLC film deposited on Si substrate by Filtered Cathodic Vacuum Arc (FCVA) technique

Energy Technology Data Exchange (ETDEWEB)

Bootkul, D., E-mail: mo_duangkhae@hotmail.com [Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Supsermpol, B.; Saenphinit, N. [Western Digital Company, Ayutthaya 13160 (Thailand); Aramwit, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Intarasiri, S., E-mail: saweat@gmail.com [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50202 (Thailand)

2014-08-15

Diamond-like carbon (DLC) films have been used in many applications due to their attractive combination of properties including chemical inertness, corrosion protection, biocompatibility, high hardness, and low wear rates. However, they still have some limitations such as high internal stresses and low toughness which lead to poor adhesion of films. Synthesis of nitrogen-doped DLC (N-DLC) offers the possibility of overcoming these limitations. In this study, DLC films, namely tetrahedral amorphous carbon (ta-C) and nitrogen doped tetrahedral amorphous carbon (ta-C:N) were deposited on single crystalline Si wafer substrates using the Filtered Cathodic Vacuum Arc (FCVA) technique. Film characterizations were carried out by Raman spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), triboindenter tester and nano-scratch tester. Measurement results showed that intentionally doping with nitrogen reduced the carbon sp{sup 3} content and increased the surface roughness in comparison with that of pure ta-C films. The hardness measurement confirmed the Raman and AFM analyses that adding nitrogen in ta-C films decreased the hardness, especially with high nitrogen content. However, the nano-scratch test revealed the increasing of the critical load with nitrogen. This work, then, extended its scope to investigate the properties of double-layer ta-C films which were composed of ta-C:N interlayer of various thickness around 10–30 nm and ta-C top-layer with thickness of around 80 nm. Microstructure characterization demonstrated that a ta-C:N interlayer gradually decreased the sp{sup 3} fraction in the films and increased film roughness whenever the ta-C:N interlayer thickness increased. In this structure, the tribological property in terms of adhesion to the Si substrate was significantly improved by about 20–90%, but the mechanical property in terms of hardness was gradually degraded by about 2–10%, compared to pure ta-C film, when the ta

A voltammetry study on the diffusion of counter ions in polypyrrole films

DEFF Research Database (Denmark)

Careem, M.A.; Velmurugu, Yogambigai; Skaarup, Steen

2006-01-01

of the films when they are used in artificial muscles or as electrodes in batteries and other devices. For the present study, PPy/DBS films were electro-polymerized on platinum wires and cycled in aqueous solutions of NaCl of concentrations ranging from 0.1 M to 5 M. Significant changes in the redox properties...

A high-current pulsed cathodic vacuum arc plasma source

International Nuclear Information System (INIS)

Oates, T.W.H.; Pigott, J.; Mckenzie, D.R.; Bilek, M.M.M.

2003-01-01

Cathodic vacuum arcs (CVAs) are well established as a method for producing metal plasmas for thin film deposition and as a source of metal ions. Fundamental differences exist between direct current (dc) and pulsed CVAs. We present here results of our investigations into the design and construction of a high-current center-triggered pulsed CVA. Power supply design based on electrolytic capacitors is discussed and optimized based on obtaining the most effective utilization of the cathode material. Anode configuration is also discussed with respect to the optimization of the electron collection capability. Type I and II cathode spots are observed and discussed with respect to cathode surface contamination. An unfiltered deposition rate of 1.7 nm per pulse, at a distance of 100 mm from the source, has been demonstrated. Instantaneous plasma densities in excess of 1x10 19 m -3 are observed after magnetic filtering. Time averaged densities an order of magnitude greater than common dc arc densities have been demonstrated, limited by pulse repetition rate and filter efficiency

Self-Standing Polypyrrole/Black Phosphorus Laminated Film: Promising Electrode for Flexible Supercapacitor with Enhanced Capacitance and Cycling Stability.

Science.gov (United States)

Luo, Shaojuan; Zhao, Jinlai; Zou, Jifei; He, Zhiliang; Xu, Changwen; Liu, Fuwei; Huang, Yang; Dong, Lei; Wang, Lei; Zhang, Han

2018-01-31

With the rapid development of portable electronics, solid-state flexible supercapacitors (SCs) are considered as one of the promising energy devices in powering electronics because of their intrinsic advantages. Polypyrrole (PPy) is an ideal electrode material in constructing flexible SCs owing to its high electrochemical activity and inherent flexibility, although its relatively low capacitance and poor cycling stability are still worthy of improvement. Herein, through the innovative introduction of black phosphorus (BP) nanosheets, we developed a laminated PPy/BP self-standing film with enhanced capacitance and cycling stability via a facile one-step electrochemical deposition method. The film exhibits a high capacitance of 497.5 F g -1 (551.7 F cm -3 ) and outstanding cycling stability of 10 000 charging/discharging cycles, thanks to BP nanosheets inducing laminated assembly which hinder dense and disordered stacking of PPy during electrodeposition, consequently providing a precise pathway for ion diffusion and electron transport together with alleviation of the structural deterioration during charge/discharge. The flexible SC fabricated by laminated films delivers a high capacitance of 452.8 F g -1 (7.7 F cm -3 ) besides its remarkable mechanical flexibility and cycling stability. Our facile strategy paves the way to improve the electrochemical performance of PPy-based SC that could serve as promising flexible energy device for portable electronics.

Radio frequency magnetron sputter-deposited indium tin oxide for use as a cathode in transparent organic light-emitting diode

International Nuclear Information System (INIS)

Chung, Choong-Heui; Ko, Young-Wook; Kim, Yong-Hae; Sohn, Choong-Yong; Hye Yong Chu; Ko Park, Sang-Hee; Lee, Jin Ho

2005-01-01

Indium tin oxide (ITO) films were prepared by radio frequency magnetron sputtering at room temperature, for use as a cathode in a transparent organic light-emitting diode (TOLED). To minimize damage to the TOLED by the ITO sputtering process, the target-to-substrate distance was increased to 20 cm. An ITO film deposited at the optimum oxygen partial pressure exhibited an electrical resistivity as low as 4.06 x 10 -4 Ω cm and a high optical transmittance of 91% in the visible range. The film was used as a transparent cathode for a TOLED with structure of an ITO coated glass substrate / Naphthylphenyldiamide (60 nm) / Tris-(8-hydroxyquinoline) aluminum (60 nm) / LiF (1 nm) / Al (2 nm) / Ag (8 nm) / ITO cathode (100 nm). A maximum luminance of 37,000 cd/m 2 was obtained. The device performance was comparable to a conventional OLED

Ionic motion in PEDOT and PPy conducting polymer bilayers

DEFF Research Database (Denmark)

Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

2006-01-01

Conducting polymer bilayers with poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), each containing dodecyl benzenesulfonate (DBS) as immobile dopant species, were synthesized galvanostatically. The electrochemical behaviour of the bilayers was investigated using cyclic voltammetry...

Incidence Angle Effect of Energetic Carbon Ions on Deposition Rate, Topography, and Structure of Ultrathin Amorphous Carbon Films Deposited by Filtered Cathodic Vacuum Arc

KAUST Repository

Wang, N.

2012-07-01

The effect of the incidence angle of energetic carbon ions on the thickness, topography, and structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) was examined in the context of numerical and experimental results. The thickness of a-C films deposited at different incidence angles was investigated in the light of Monte Carlo simulations, and the calculated depth profiles were compared with those obtained from high-resolution transmission electron microscopy (TEM). The topography and structure of the a-C films were studied by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The film thickness decreased with the increase of the incidence angle, while the surface roughness increased and the content of tetrahedral carbon hybridization (sp 3) decreased significantly with the increase of the incidence angle above 45° , measured from the surface normal. TEM, AFM, and XPS results indicate that the smoothest and thinnest a-C films with the highest content of sp 3 carbon bonding were produced for an incidence angle of 45°. The findings of this study have direct implications in ultrahigh-density magnetic recording, where ultrathin and smooth a-C films with high sp 3 contents are of critical importance. © 2012 IEEE.

Bending behaviour of polypyrrole films with anisotropy for artificial muscles

International Nuclear Information System (INIS)

Onoda, Mitsuyoshi; Shonaka, Hirokazu; Tada, Kazuya

2006-01-01

A polypyrrole (PPy) film electrochemically grown in a thin slab vessel consisting of poly(tetrafluoroethylene) walls exhibits a notable anisotropy along the thickness direction. This anisotropy allows the film to bend in a regular direction upon electrochemical undoping and revert upon doping. In this study, the size effect, i.e. the length dependence of reduction current, of the actuator has been studied. The length was changed by trimming the tip of the actuator, 12 mm of which was initially soaked in an electrolyte. It has been clarified that current saturates when the actuator exceeds a certain length. This may reflect the reduction in the conductivity of PPy upon undoping, which makes the tip of the actuator almost insulated from the power source. It is also found that the width of the actuator and the electrolyte do not influence the size effect

Cross-stacked carbon nanotube film as an additional built-in current collector and adsorption layer for high-performance lithium sulfur batteries.

Science.gov (United States)

Sun, Li; Kong, Weibang; Li, Mengya; Wu, Hengcai; Jiang, Kaili; Li, Qunqing; Zhang, Yihe; Wang, Jiaping; Fan, Shoushan

2016-02-19

Cross-stacked carbon nanotube (CNT) film is proposed as an additional built-in current collector and adsorption layer in sulfur cathodes for advanced lithium sulfur (Li-S) batteries. On one hand, the CNT film with high conductivity, microstructural rough surface, high flexibility and mechanical durability retains stable and direct electronic contact with the sulfur cathode materials, therefore decreasing internal resistivity and suppressing polarization of the cathode. On the other hand, the highly porous structure and the high surface area of the CNT film provide abundant adsorption points to support and confine sulfur cathode materials, alleviate their aggregation and promote high sulfur utilization. Moreover, the lightweight and compact structure of the CNT film adds no extra weight or volume to the sulfur cathode, benefitting the improvement of energy densities. Based on these characteristics, the sulfur cathode with a 100-layer cross-stacked CNT film presents excellent rate performances with capacities of 986, 922 and 874 mAh g(-1) at cycling rates of 0.2C, 0.5C and 1C for sulfur loading of 60 wt%, corresponding to an improvement of 52%, 109% and 146% compared to that without a CNT film. Promising cycling performances are also demonstrated, offering great potential for scaled-up production of sulfur cathodes for Li-S batteries.

OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

Energy Technology Data Exchange (ETDEWEB)

Dr. Ralph E. White; Dr. Branko N. Popov

2001-10-01

The dissolution of NiO cathodes during cell operation is a limiting factor to the successful commercialization of molten carbonate fuel cells (MCFCs). Lithium cobalt oxide coating onto the porous nickel electrode has been adopted to modify the conventional MCFC cathode which is believed to increase the stability of the cathodes in the carbonate melt. The material used for surface modification should possess thermodynamic stability in the molten carbonate and also should be electro catalytically active for MCFC reactions. Lithium Cobalt oxide was coated on Ni cathode by a sol-gel coating. The morphology and the LiCoO{sub 2} formation of LiCoO{sub 2} coated NiO was studied using scanning electron microscopy and X-Ray diffraction studies respectively. The electrochemical performance lithium cobalt oxide coated NiO cathodes were investigated with open circuit potential measurement and current-potential polarization studies. These results were compared to that of bare NiO. Dissolution of nickel into the molten carbonate melt was less in case of lithium cobalt oxide coated nickel cathodes. LiCoO{sub 2} coated on the surface prevents the dissolution of Ni in the melt and thereby stabilizes the cathode. Finally, lithium cobalt oxide coated nickel shows similar polarization characteristics as nickel oxide. Conventional theoretical models for the molten carbonate fuel cell cathode are based on the thin film agglomerate model. The principal deficiency of the agglomerate model, apart from the simplified pore structure assumed, is the lack of measured values for film thickness and agglomerate radius. Both these parameters cannot be estimated appropriately. Attempts to estimate the thickness of the film vary by two orders of magnitude. To avoid these problems a new three phase homogeneous model has been developed using the volume averaging technique. The model considers the potential and current variation in both liquid and solid phases. Using this approach, volume averaged

Effect of Si on DC arc plasma generation from Al-Cr and Al-Cr-Si cathodes used in oxygen

Science.gov (United States)

Zhirkov, I.; Landälv, L.; Göthelid, E.; Ahlgren, M.; Eklund, P.; Rosen, J.

2017-02-01

Al2O3 alloyed with Cr is an important material for the tooling industry. It can be synthesized from an arc discharge using Al-Cr cathodes in an oxygen atmosphere. Due to formation of Al-rich oxide islands on the cathode surface, the arc process stability is highly sensitive to oxygen pressure. For improved stability, the use of Al0.70Cr0.25Si0.05 cathodes has previously been suggested, where Si may reduce island formation. Here, we have investigated the effect of Si by comparing plasma generation and thin film deposition from Al0.7Cr0.3 and Al0.7Cr0.25Si0.05 cathodes. Plasma ion composition, ion energies, ion charge states, neutral species, droplet formation, and film composition have been characterized at different O2 flow rates for arc currents of 60 and 90 A. Si and related compounds are detected in plasma ions and in plasma neutrals. Scanning electron microscopy and energy dispersive X-ray analysis show that the cathode composition and the film composition are the same, with Si present in droplets as well. The effect of Si on the process stability, ion energies, and ion charge states is found to be negligible compared to that of the arc current. The latter is identified as the most relevant parameter for tuning the properties of the reactive discharge. The present work increases the fundamental understanding of plasma generation in a reactive atmosphere, and provides input for the choice of cathode composition and process parameters in reactive DC arc synthesis.

X- or gamma ray converter and manufacturing method for its cathode system

Energy Technology Data Exchange (ETDEWEB)

Baeuerlein, R; Uhl, D; Diepers, H; Jablonski, K H

1981-02-05

The X-ray converter serves for application in medical diagnostics. For the cathode system of the converter a system based on low-pressure ionography is suited making use of the X-ray photoelectric emission. The electrodes of the cathode system consist of double-layer films with two external conduction layers and an insulator in between. As an auxiliary voltage can be applied between the individual layers the field gradient in the holes may be adjusted, thus increasing the quantum yield.

X- or gamma ray converter and manufacturing method for its cathode system

International Nuclear Information System (INIS)

Baeuerlein, R.; Uhl, D.; Diepers, H.; Jablonski, K.H.

1981-01-01

The X-ray converter serves for application in medical diagnostics. For the cathode system of the converter a system based on low-pressure ionography is suited making use of the X-ray photoelectric emission. The electrodes of the cathode system consist of double-layer films with two external conduction layers and an insulator in between. As an auxiliary voltage can be applied between the individual layers the field gradient in the holes may be adjusted, thus increasing the quantum yield. (orig./HP)

Electricity generation coupled with wastewater treatment using a microbial fuel cell composed of a modified cathode with a ceramic membrane and cellulose acetate film.

Science.gov (United States)

Seo, Ha Na; Lee, Woo Jin; Hwang, Tae Sik; Park, Doo Hyun

2009-09-01

A noncompartmented microbial fuel cell (NCMFC) composed of a Mn(IV)-carbon plate and a Fe(III)-carbon plate was used for electricity generation from organic wastewater without consumption of external energy. The Fe(III)-carbon plate, coated with a porous ceramic membrane and a semipermeable cellulose acetate film, was used as a cathode, which substituted for the catholyte and cathode. The Mn(IV)-carbon plate was used as an anode without a membrane or film coating. A solar cell connected to the NCMFC activated electricity generation and bacterial consumption of organic matter contained in the wastewater. More than 99 degrees of the organic matter was biochemically oxidized during wastewater flow through the four NCMFC units. A predominant bacterium isolated from the anode surface in both the conventional and the solar cell-linked NCMFC was found to be more than 99 degrees similar to a Mn(II)-oxidizing bacterium and Burkeholderia sp., based on 16S rDNA sequence analysis. The isolate reacted electrochemically with the Mn(IV)-modified anode and produced electricity in the NCMFC. After 90 days of incubation, a bacterial species that was enriched on the Mn(IV)-modified anode surface in all of the NCMFC units was found to be very similar to the initially isolated predominant species by comparing 16S rDNA sequences.

Characterization of polypyrrole films electrosynthesized onto titanium in the presence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)

International Nuclear Information System (INIS)

Flamini, D.O.; Saidman, S.B.

2010-01-01

Films of polypyrrole (PPy) were successfully electrosynthesized onto titanium in neutral and alkaline solutions of sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT or AOT) by potentiodynamic, galvanostatic and potentiostatic techniques. Results of the characterization of the films by cyclic voltammetry, scanning electron microscopy (SEM) and adhesion measurements are presented. It was found that the AOT molecule remains entrapped within the polymer matrix. The initial growth of the polymer produces electroactive toroidal deposits whereas for electropolymerization of longer duration the typical globular structure is developed. Adherence to Ti increases with deposition time and this result is interpreted as a consequence of the growth of a composite PPy/Ti oxide.

Dependence of the constitution, microstructure and electrochemical behaviour of magnetron sputtered Li-Ni-Mn-Co-O thin film cathodes for lithium-ion batteries on the working gas pressure and annealing conditions

International Nuclear Information System (INIS)

Strafela, Marc; Fischer, Julian; Leiste, Harald; Rinke, Monika; Bergfeldt, Thomas; Seifert, Hans Juergen; Ulrich, Sven; Music, Denis; Chang, Keke; Schneider, Jochen

2017-01-01

Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 as a cathode material for lithium ion batteries shows good thermal stability, high reversible capacity (290 mAh g -1 ), good rate capability and better results in terms of environmental friendliness. In this paper thin film cathodes in the material system Li-Ni-Mn-Co-O were deposited onto silicon and stainless steel substrates, by non-reactive r.f. magnetron sputtering from a ceramic Li 1.18 (Ni 0.39 Mn 0.19 Co 0.35 )O 1.97 target at various argon working gas pressures between 0.2 Pa and 20 Pa. A comprehensive study on the composition and microstructure was carried out. The results showed that the elemental composition varies depending on argon working gas pressure. The elemental composition was determined by inductively coupled plasma optical emission spectroscopy in combination with carrier gas hot extraction. The films showed different grain orientations depending argon working gas pressures. The degree of cation order in the lattice structure of the films deposited at 0.5 Pa and 7 Pa argon working gas pressure, was increased by annealing in an argon/oxygen atmosphere at different pressures for one hour. The microstructure of the films varies with annealing gas pressure and is characterized using X-ray diffraction and unpolarized micro-Raman spectroscopy at room temperature. Electrochemical characterization of as-deposited and annealed films was carried out by galvanostatic cycling in Li-Ni-Mn-Co-O half-cells against metallic lithium. Correlations between process parameters, constitution, microstructure and electrochemical behaviour are discussed in detail.

Analysis of the dopant distribution in Co-deposited organic thin films by scanning transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Paredes, Yolanda A. [Center of Nanotechnology and Nanoscience, Universidad de las Fuerzas Armadas ESPE, Sangolqui 171-5-31B (Ecuador); Campos, Andrea P.C.; Achete, Carlos A. [DIMAT—INMETRO, Xerém, Duque de Caxias, RJ 25250-020 (Brazil); Cremona, Marco [DIMAT—INMETRO, Xerém, Duque de Caxias, RJ 25250-020 (Brazil); Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, PUC-Rio, Rio de Janeiro, RJ 22453-970 (Brazil)

2015-12-01

Organic light-emitting diodes using phosphorescent dyes (PHOLEDs) have excellent performance, with internal quantum efficiencies approaching 100%. To maximize their performance, PHOLED devices use a conductive organic host material with a sufficiently dispersed phosphorescent guest to avoid concentration quenching. Fac-tris(2-phenylpyridine) iridium, [Ir(ppy){sub 3}] is one of the most widely used green phosphorescent organic compounds. In this work, we used scanning transmission electron microscopy (STEM) equipped with HAADF (high-angle annular dark-field) and EDS (energy dispersive X-ray spectroscopy) detectors to analyze the distribution of the [Ir(ppy){sub 3}] concentration in the host material. This analysis technique, employed for the first time in co-deposited organic thin films, can simultaneously obtain an image and its respective chemical information, allowing for definitive characterization of the distribution and morphology of [Ir(ppy){sub 3}]. The technique was also used to analyze the effect of the vibration of the substrate during thermal co-deposition of the [Ir(ppy){sub 3}] molecules into an organic matrix. - Highlights: • We present a methodology to analyze the dopant distribution in organic thin films. • The method combines HAADF-STEM imaging and EDS X-ray spectroscopy. • Ir(ppy){sub 3} dopant was co-deposited into Spiro2-CBP organic matrix. • The dopant was co-deposited with and without substrate vibration. • Images and chemical information of the dopant were simultaneously obtained.

Cathode readout with stripped resistive drift tubes

International Nuclear Information System (INIS)

Bychkov, V.N.; Kekelidze, G.D.; Novikov, E.A.; Peshekhonov, V.D.; Shafranov, M.D.; Zhiltsov, V.E.

1995-01-01

A straw tube drift chamber prototype has been constructed and tested. The straw tube material is mylar film covered with a carbon layer with a resistivity of 0.5, 30 and 70 kΩ/□. Both the anode wire and the cathode strip signals were detected to study the behaviour of the chamber in the presence of X-ray ionization. The construction and the results of the study are presented. (orig.)

Cathode readout with stripped resistive drift tubes

Science.gov (United States)

Bychkov, V. N.; Kekelidze, G. D.; Novikov, E. A.; Peshekhonov, V. D.; Shafranov, M. D.; Zhiltsov, V. E.

1995-12-01

A straw tube drift chamber prototype has been constructed and tested. The straw tube material is mylar film covered with a carbon layer with a resistivity of 0.5, 30 and 70 kΩ/□. Both the anode wire and the cathode strip signals were detected to study the behaviour of the chamber in the presence of X-ray ionization. The construction and the results of the study are presented.

Impedance of thin film cathodes: thickness and current collector dependence

NARCIS (Netherlands)

Boukamp, Bernard A.; Hildenbrand, N.; Bouwmeester, Henricus J.M.; Blank, David H.A.

2015-01-01

The influence of the layer thickness of mixed ionic–electronic conducting (MIEC) cathodes and the type of noble metal current collector on the apparent surface exchange resistance is studied with impedance spectroscopy. The impedance data is analyzed with the ‘General Finite Length Diffusion’

Electrocatalytic reduction of oxygen at glassy carbon electrode modified by polypyrrole/anthraquinones composite film in various pH media

International Nuclear Information System (INIS)

Valarselvan, S.; Manisankar, P.

2011-01-01

Graphical abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . Highlights: → Hydroxyl derivatives of anthraquinones as electrocatalysts for dioxygen reduction. → AQ/PPy composite film on GC electrode exhibits potent electrocatalytic activity. → Substituent groups influence electrocatalytic dioxygen reduction. → Surface coverage varies the rate of electrocatalytic dioxygen reduction. - Abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. The electrochemical behaviour of the modified electrodes was examined in various pH media and both the formal potential of anthraquinones and reduction potential of dioxygen exhibited pH dependence. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . pH 6.0 was chosen as the most suitable medium to study the electrocatalysis by comparing the peak potential of oxygen reduction and enhancement in peak current for oxygen reduction. The diffusion coefficient values of AQ at the modified electrodes and the number of electrons involved in AQ reduction were evaluated by chronoamperometric and chronocoulometric techniques, respectively. In addition, hydrodynamic voltammetric studies showed the involvement of two electrons in O 2 reduction. The mass specific activity of AQ used, the diffusion coefficient of oxygen and the heterogeneous rate constants for the oxygen reduction at the surface of modified electrodes were also determined by rotating disk voltammetry.

Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

Energy Technology Data Exchange (ETDEWEB)

Pournaghi-Azar, M.H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)]. E-mail: pournaghiazar@tabrizu.ac.ir; Nahalparvari, H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2005-03-15

The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN){sub 6}{sup 4-} and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement.

Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

International Nuclear Information System (INIS)

Pournaghi-Azar, M.H.; Nahalparvari, H.

2005-01-01

The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN) 6 4- and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement

Frequency of reporting on patient and public involvement (PPI) in research studies published in a general medical journal: a descriptive study.

Science.gov (United States)

Price, Amy; Schroter, Sara; Snow, Rosamund; Hicks, Melissa; Harmston, Rebecca; Staniszewska, Sophie; Parker, Sam; Richards, Tessa

2018-03-23

While documented plans for patient and public involvement (PPI) in research are required in many grant applications, little is known about how frequently PPI occurs in practice. Low levels of reported PPI may mask actual activity due to limited PPI reporting requirements. This research analysed the frequency and types of reported PPI in the presence and absence of a journal requirement to include this information. A before and after comparison of PPI reported in research papers published in The BMJ before and 1 year after the introduction of a journal policy requiring authors to report if and how they involved patients and the public within their papers. Between 1 June 2013 and 31 May 2014, The BMJ published 189 research papers and 1 (0.5%) reported PPI activity. From 1 June 2015 to 31 May 2016, following the introduction of the policy, The BMJ published 152 research papers of which 16 (11%) reported PPI activity. Patients contributed to grant applications in addition to designing studies through to coauthorship and participation in study dissemination. Patient contributors were often not fully acknowledged; 6 of 17 (35%) papers acknowledged their contributions and 2 (12%) included them as coauthors. Infrequent reporting of PPI activity does not appear to be purely due to a failure of documentation. Reporting of PPI activity increased after the introduction of The BMJ 's policy, but activity both before and after was low and reporting was inconsistent in quality. Journals, funders and research institutions should collaborate to move us from the current situation where PPI is an optional extra to one where PPI is fully embedded in practice throughout the research process. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Enhanced stability of solid oxide fuel cells by employing a modified cathode-interlayer interface with a dense La0.6Sr0.4Co0.2Fe0.8O3-δ thin film

Science.gov (United States)

De Vero, Jeffrey C.; Develos-Bagarinao, Katherine; Kishimoto, Haruo; Ishiyama, Tomohiro; Yamaji, Katsuhiko; Horita, Teruhisa; Yokokawa, Harumi

2018-02-01

In La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode/Gd-doped ceria (GDC)/yttria-stabilized zirconia (YSZ)-electrolyte based solid oxide fuel cells (SOFCs), one of the key issues affecting performance and long-term stability is the apparent deactivation of LSCF cathode by the presence of secondary phases such as SrZrO3 at the interfaces. Herein, we report that by modifying the cathode-interlayer interface with a dense LSCF thin film, the severe cation interdiffusion is suppressed especially the fast gas or surface diffusion of Sr into adjacent GDC-interlayer/YSZ-electrolyte resulting in the significant reduction of SrZrO3 formation at the interfaces improving cell stability. In order to understand the present results, the interface chemistry is carefully considered and discussed. The results show that modification of cathode-interlayer interfaces is an important strategy for improving the lifetime of SOFCs.

Fabrication of mesoporous cerium dioxide films by cathodic electrodeposition.

Science.gov (United States)

Kim, Young-Soo; Lee, Jin-Kyu; Ahn, Jae-Hoon; Park, Eun-Kyung; Kim, Gil-Pyo; Baeck, Sung-Hyeon

2007-11-01

Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templating agent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating.

Device quality ZnO grown using a Filtered Cathodic Vacuum Arc

International Nuclear Information System (INIS)

Elzwawi, Salim; Kim, Hyung Suk; Heinhold, Robert; Lynam, Max; Turner, Gary; Partridge, Jim G.; McCulloch, Dougal G.

2012-01-01

In this paper we report on the structural, electrical and optical characteristics of unintentionally doped ZnO films grown on a-plane sapphire substrates using the Filtered Cathodic Vacuum Arc (FCVA) technique. The resulting films showed considerable promise for device applications with properties including high transparency, moderate intrinsic carrier concentrations (10 17 -10 19 cm -3 ), electron mobilities up to 30 cm 2 /Vs, low surface roughness (typically <2% of film thickness) and well-structured photoluminescence. Post-annealing in oxygen at temperatures up to 800 °C produced significant improvements in the properties of these films. Silver oxide Schottky diodes fabricated on FCVA ZnO showed ideality factors as low as 1.20 and good sensitivity to ultraviolet light.

A validity assessment of the Progress out of Poverty Index (PPI)™.

Science.gov (United States)

Desiere, Sam; Vellema, Wytse; D'Haese, Marijke

2015-04-01

Development organisations need easy-to-use and quick-to-implement indicators to quantify poverty when requested to measure program impact. In this paper we assess the validity of the Progress out of Poverty Index (PPI)™, a country-specific indicator based on ten closed questions on directly observable household characteristics, by its compliance to the SMART criteria. Each response receives a pre-determined score, such that the sum of these scores can be converted into the likelihood the household is living below the poverty line. We focus on the PPI scorecard for Rwanda, which was validated using two national household surveys conducted in 2005/06 and 2010/11. The PPI is Specific, Measurable, Available cost effectively, and Timely available. Yet, its Relevance depends on the way it is used. Although it accurately distinguishes poor from non-poor households, making it a useful reporting tool, its limited sensitivity to changes in poverty status restricts its usefulness for evaluating the impact of development projects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design of Novel Organic Thin Film Transistors for Wearable Electronics

Science.gov (United States)

2012-08-01

TECHNOLOGICAL ACHIEVEMENTS 7 1.0 INTRODUCTION 7 2.0 CHARACTERISTICS OF OTFTS 3.0 USE OF PHTHALOCYANINE AS A BIOSENSOR 8 4.0 CATHODIC ELECTRODEPOSITION ...public release; distribution is unlimited. 12 4.0 CATHODIC ELECTRODEPOSITION OF ANATASE HIGH DİELECTRIC CONSTANT TITANIA Polycrystalline...oxidised film which is used and left in air for 3 months. 11 5 Raman Spectra for TiO2 films electrodeposited at temperatures: (a) 296K, (b) 318K

Identifying protein complex by integrating characteristic of core-attachment into dynamic PPI network.

Directory of Open Access Journals (Sweden)

Xianjun Shen

Full Text Available How to identify protein complex is an important and challenging task in proteomics. It would make great contribution to our knowledge of molecular mechanism in cell life activities. However, the inherent organization and dynamic characteristic of cell system have rarely been incorporated into the existing algorithms for detecting protein complexes because of the limitation of protein-protein interaction (PPI data produced by high throughput techniques. The availability of time course gene expression profile enables us to uncover the dynamics of molecular networks and improve the detection of protein complexes. In order to achieve this goal, this paper proposes a novel algorithm DCA (Dynamic Core-Attachment. It detects protein-complex core comprising of continually expressed and highly connected proteins in dynamic PPI network, and then the protein complex is formed by including the attachments with high adhesion into the core. The integration of core-attachment feature into the dynamic PPI network is responsible for the superiority of our algorithm. DCA has been applied on two different yeast dynamic PPI networks and the experimental results show that it performs significantly better than the state-of-the-art techniques in terms of prediction accuracy, hF-measure and statistical significance in biology. In addition, the identified complexes with strong biological significance provide potential candidate complexes for biologists to validate.

Oesophageal narrowing on barium oesophagram is more common in adult patients with eosinophilic oesophagitis than PPI-responsive oesophageal eosinophilia.

Science.gov (United States)

Podboy, A; Katzka, D A; Enders, F; Larson, J J; Geno, D; Kryzer, L; Alexander, J

2016-06-01

To date there have been no clear features that aid in differentiating patients with eosinophilic oesophagitis (EoE) from PPI-responsive oesophageal eosinophilia (PPI-REE). However, barium swallow roentgenography is a more sensitive and specific measure to detect subtle fibrostenotic remodeling changes present in EoE. We aim to characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE. To characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE. We performed a retrospective cohort analysis on data collected from a tertiary referral centre population from 2010 to 2015. Data from 66 patients with EoE and 28 patients with PPI-REE were analysed. Cases were adults who met consensus guidelines for EOE, and had a barium swallow study within 6 months of the index endoscopy. Clinical, endoscopic, histiological and barium swallow findings were collected. Patients with EoE reported similar characteristics as PPI-REE patients, except EoE patients were younger (35.6 vs. 46.6 years; P = 0.011), had earlier symptom onset (29.0 vs. 38.0 years; P = 0.026), and smaller oesophageal diameters on barium swallow (19.5 mm vs. 20; P = 0.042). Patients with EoE were more likely to have distal strictures (EoE 77% vs. 25%; P = 0.02) and, importantly, a greater likelihood of small calibre oesophagus (51.5% vs. 17.9%; P = 0.002). Moreover, EoE patients had a higher probability of developing small calibre oesophagus after 20 years of symptoms (72.3% vs. 30.2%; P = 0.074) compared to PPI-REE patients. When compared with eosinophilic oesophagitis, PPI-REE patients demonstrate findings that suggest PPI-responsive oesophageal eosinophilia to be a later onset, less aggressive form of oesophageal stricturing disease than eosinophilic oesophagitis. © 2016 John Wiley & Sons Ltd.

Evolutionary, kinetic and thermodynamic aspects on the bioenergetics of inorganic pyrophosphate (PPi) and adenosine triphosphate (ATP)

International Nuclear Information System (INIS)

Baltscheffsky, H.; Baltscheffsky, M.

1995-01-01

Energy barriers for energy carriers are of fundamental significance for the successful operation of the bioenergetic reactions in living cells. PPi and ATP are outstanding ''energy-rich'' examples of molecular ''energy currencies'' in biological systems, with kinetic barriers preventing excessively fast thermodynamically feasible hydrolysis from occurring. The barriers may be considered to facilitate the energy coupling roles of these phosphate compounds, which are to secure growth and maintain numerous other energy requiring functions. The enzymes involved in overcoming the energies of activation of the bioenergetic reactions have evolved to be very well tuned for their roles. Three aspects will be discussed in some detail. The first is the fact that ATP at neutral pH is considerably more energy-rich than PPi, which thus has been called a ''poor man's ATP''. This is exemplified by the kinetic and thermodynamic differences observed between the requirements for the photosynthetic formation of PPi and ATP in certain photobacterial chromatophores by varying levels of energy supply. At lower pH, PPi and ATP are equally energy-rich, which may be of significance for acidophiles. The second concerns the possible evolutionary significance of the finding that, in the dark, a pH gradient suffices to drive extensive PPi synthesis, whereas ATP synthesis requires both a pH gradient and a membrane potential (Strid et al, Biochim. Biophys. Acta 892 (1987) 236-244). Thirdly, PPi as the most plausible predecessor to ATP in the origin and early evolution of life, will be discussed. (author). Abstract only

Mechanisms of LiCoO2 Cathode Degradation by Reaction with HF and Protection by Thin Oxide Coatings.

Science.gov (United States)

Tebbe, Jonathon L; Holder, Aaron M; Musgrave, Charles B

2015-11-04

Reactions of HF with uncoated and Al and Zn oxide-coated surfaces of LiCoO2 cathodes were studied using density functional theory. Cathode degradation caused by reaction of HF with the hydroxylated (101̅4) LiCoO2 surface is dominated by formation of H2O and a LiF precipitate via a barrierless reaction that is exothermic by 1.53 eV. We present a detailed mechanism where HF reacts at the alumina coating to create a partially fluorinated alumina surface rather than forming AlF3 and H2O and thus alumina films reduce cathode degradation by scavenging HF and avoiding H2O formation. In contrast, we find that HF etches monolayer zinc oxide coatings, which thus fail to prevent capacity fading. However, thicker zinc oxide films mitigate capacity loss by reacting with HF to form a partially fluorinated zinc oxide surface. Metal oxide coatings that react with HF to form hydroxyl groups over H2O, like the alumina monolayer, will significantly reduce cathode degradation.

Characterization of n and p-type ZnO thin films grown by pulsed filtered cathodic vacuum arc system

International Nuclear Information System (INIS)

Kavak, H.; Erdogan, E.N.; Ozsahin, I.; Esen, R.

2010-01-01

Full text : Semiconductor ZnO thin films with wide band gap attract much interest due to their properties such as chemical stability in hydrogen plasma, high optical transparency in the visible and nearinfrared region. Due to these properties ZnO oxide is a promising materials for electronic or optoelectronic applications such as solar cell (as an antireflecting coating and a transparent conducting material), gas sensors, surface acoustic wave devices. The purpose of this research is to improve the properties of n and p-type ZnO thin films for device applications. Polycrystalline ZnO is naturally n-type and very difficult to dope to make p-type. Therefore nowadays hardly produced p-type ZnO attracts a lot of attention. Nitrogen considered as the best dopant for p-type ZnO thin films.The transparent, conductive and very precise thickness controlled n and p-type semiconducting nanocrystalline ZnO thin films were prepared by pulsed filtered cathodic vacuum arc deposition (PFCVAD) method. Structural, optical and electrical properties of these films were investigated. And also photoluminescence properties of these films were investigated. Transparent p-type ZnO thin films were produced by oxidation of PFCVAD deposited zinc nitride. Zinc nitride thin films were deposited with various thicknesses and under different oxygen pressures on glass substrates. Zinc nitride thin films, which were deposited at room temperatures, were amorphous and the optical transmission was below 70%. For oxidation zinc nitride, the sample was annealed in air starting from 350 degrees Celsium up to 550 degrees Celsium for one hour duration. These XRD patterns imply that zinc nitride thin films converted to zinc oxide thin films with the same hexagonal crystalline structures of ZnO. The optical measurements were made for each annealing temperature and the optical transmissions of ZnO thin films were found better than 90 percent in visible range after annealing over 350 degrees Celsium. By

Dependence of the constitution, microstructure and electrochemical behaviour of magnetron sputtered Li-Ni-Mn-Co-O thin film cathodes for lithium-ion batteries on the working gas pressure and annealing conditions

Energy Technology Data Exchange (ETDEWEB)

Strafela, Marc; Fischer, Julian; Leiste, Harald; Rinke, Monika; Bergfeldt, Thomas; Seifert, Hans Juergen; Ulrich, Sven [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Applied Materials (IAM); Music, Denis; Chang, Keke; Schneider, Jochen [RWTH Aachen Univ. (Germany). Materials Chemistry

2017-11-15

Li(Ni{sub 1/3}Mn{sub 1/3}Co{sub 1/3})O{sub 2} as a cathode material for lithium ion batteries shows good thermal stability, high reversible capacity (290 mAh g{sup -1}), good rate capability and better results in terms of environmental friendliness. In this paper thin film cathodes in the material system Li-Ni-Mn-Co-O were deposited onto silicon and stainless steel substrates, by non-reactive r.f. magnetron sputtering from a ceramic Li{sub 1.18}(Ni{sub 0.39}Mn{sub 0.19}Co{sub 0.35})O{sub 1.97} target at various argon working gas pressures between 0.2 Pa and 20 Pa. A comprehensive study on the composition and microstructure was carried out. The results showed that the elemental composition varies depending on argon working gas pressure. The elemental composition was determined by inductively coupled plasma optical emission spectroscopy in combination with carrier gas hot extraction. The films showed different grain orientations depending argon working gas pressures. The degree of cation order in the lattice structure of the films deposited at 0.5 Pa and 7 Pa argon working gas pressure, was increased by annealing in an argon/oxygen atmosphere at different pressures for one hour. The microstructure of the films varies with annealing gas pressure and is characterized using X-ray diffraction and unpolarized micro-Raman spectroscopy at room temperature. Electrochemical characterization of as-deposited and annealed films was carried out by galvanostatic cycling in Li-Ni-Mn-Co-O half-cells against metallic lithium. Correlations between process parameters, constitution, microstructure and electrochemical behaviour are discussed in detail.

Development of a sensor prepared by entrapment of MIP particles in electrosynthesised polymer films for electrochemical detection of ephedrine.

Science.gov (United States)

Mazzotta, E; Picca, R A; Malitesta, C; Piletsky, S A; Piletska, E V

2008-02-28

A voltammetric sensor for (-)-ephedrine has been prepared by a novel approach based on immobilisation of an imprinted polymer for ephedrine (MIPE) in an electrosynthesised polypyrrole (PPY) film. Composite films were grown potentiostatically at 1.0 V vs. Pt (QRE) on a glassy carbon electrode using an unconventional "upside-down" (UD) geometry for the three-electrode cell. As a consequence, a high MIP loading was obtained, as revealed by SEM. The sensor response was evaluated, after overoxidation of PPY matrix, by cyclic voltammetry after pre-concentration in a buffered solution of analyte in 0.5-3 mM concentration range. An ephedrine peak at approximately 0.9 V increasing with concentration and saturating at high concentrations was evident. PPY-modified electrode showed a response, which was distinctly lower than the MIP response for the same concentration of the template. The effect of potential interferences including compounds usually found in human fluids (ascorbic acid, uric acid, urea, glucose, sorbitol, glycine, dopamine) was examined.

Tautomeric forms of PPI dendrimers functionalized with 4-(4′-ethoxybenzoyloxy)salicylaldehyde chromophores

International Nuclear Information System (INIS)

Franckevičius, M.; Vaišnoras, R.; Marcos, M.; Serrano, J.L.; Gruodis, A.; Galikova, N.; Gulbinas, V.

2012-01-01

Highlights: ► SA chromophore groups are formed by bonding terminal groups to PPI dendrimers. ► SA chromophore groups reveal four most stable tautomeric forms. ► Tautomeric properties of SA groups depend on the dendrimer generation and solvent. ► Aggregation of SA chromophores facilitates formation of the trans-keto tautomers. ► Fluorescence of PPI SA dendrimers is attributed to nπ ∗ states of keto tautomers. -- Abstract: Bonding of the promesogenic unit derived from 4-(4′-ethoxybenzoyloxy)salicylaldehyde to the amino terminated PPI dendrimer chains results in formation of the salicylidenimine chromophore groups. Absorption and fluorescence investigations of the dendrimer solutions supported by the quantum chemistry calculations revealed that the chromophore groups may exist in enol and keto tautomeric forms with relative concentrations depending on the dendrimer generation and solvent. The dendrimer fluorescence is attributed to nπ ∗ states of keto tautomers which may also be formed from excited enol tautomers.

Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

International Nuclear Information System (INIS)

Wu Liankui; Hu Jiming; Zhang Jianqing

2012-01-01

Highlights: ► Metallic zinc is doped into organosilane films by one-step electrodeposition. ► The composite films exhibit the improved corrosion resistance of mild steels. ► Zinc-doping provides additional cathodic protection to the mild steels. - Abstract: Organosilane/zinc composite films are prepared by one-step electrodeposition onto cold-rolled steels for corrosion protection. Electrochemical impedance spectroscopy measurement, bulk solution immersion and wet heat tests all show that the composite films have improved corrosion performance. X-ray photoelectron spectroscopy measurement suggests the successful encapsulation of metallic zinc. The embedding of metallic zinc results in negative shift in open-circuit potential of the film-covered electrodes. Such cathodic protection effect given by the metallic zinc provides the improved corrosion resistance of the composite films.

Preparation of stable magnetic nanofluids containing Fe3O4@PPy nanoparticles by a novel one-pot route

Directory of Open Access Journals (Sweden)

Zhao Baobao

2011-01-01

Full Text Available Abstract Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy nanoparticles (NPs were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit was used as the reducing reagent to form Fe3O4 NPs. The as-prepared nanofluid can keep long-term stability. The Fe3O4@PPy NPs can still keep dispersing well after the nanofluid has been standing for 1 month and no sedimentation is found. The polymerization reaction of the pyrrole monomers took place with Fe3+ ions as the initiator, in which these Fe3+ ions remained in the solution adsorbed on the surface of the Fe3O4 NPs. Thus, the core-shell NPs of Fe3O4@PPy were obtained. The particle size of the as-prepared Fe3O4@PPy can be easily controlled from 7 to 30 nm by the polymerization reaction of the pyrrole monomers. The steric stabilization and weight of the NPs affect the stability of the nanofluids. The as-prepared Fe3O4@PPy NPs exhibit superparamagnetic behavior.

PPI-IRO: A two-stage method for protein-protein interaction extraction based on interaction relation ontology

KAUST Repository

Li, Chuanxi

2014-01-01

Mining Protein-Protein Interactions (PPIs) from the fast-growing biomedical literature resources has been proven as an effective approach for the identifi cation of biological regulatory networks. This paper presents a novel method based on the idea of Interaction Relation Ontology (IRO), which specifi es and organises words of various proteins interaction relationships. Our method is a two-stage PPI extraction method. At fi rst, IRO is applied in a binary classifi er to determine whether sentences contain a relation or not. Then, IRO is taken to guide PPI extraction by building sentence dependency parse tree. Comprehensive and quantitative evaluations and detailed analyses are used to demonstrate the signifi cant performance of IRO on relation sentences classifi cation and PPI extraction. Our PPI extraction method yielded a recall of around 80% and 90% and an F1 of around 54% and 66% on corpora of AIMed and Bioinfer, respectively, which are superior to most existing extraction methods. Copyright © 2014 Inderscience Enterprises Ltd.

Characterizations of photoconductivity of graphene oxide thin films

Directory of Open Access Journals (Sweden)

Shiang-Kuo Chang-Jian

2012-06-01

Full Text Available Characterizations of photoresponse of a graphene oxide (GO thin film to a near infrared laser light were studied. Results showed the photocurrent in the GO thin film was cathodic, always flowing in an opposite direction to the initial current generated by the preset bias voltage that shows a fundamental discrepancy from the photocurrent in the reduced graphene oxide thin film. Light illumination on the GO thin film thus results in more free electrons that offset the initial current. By examining GO thin films reduced at different temperatures, the critical temperature for reversing the photocurrent from cathodic to anodic was found around 187°C. The dynamic photoresponse for the GO thin film was further characterized through the response time constants within the laser on and off durations, denoted as τon and τoff, respectively. τon for the GO thin film was comparable to the other carbon-based thin films such as carbon nanotubes and graphenes. τoff was, however, much larger than that of the other's. This discrepancy was attributable to the retardation of exciton recombination rate thanks to the existing oxygen functional groups and defects in the GO thin films.

Structure of MoCN films deposited by cathodic arc evaporation

Energy Technology Data Exchange (ETDEWEB)

Gilewicz, A., E-mail: adam.gilewicz@tu.koszalin.pl [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland); Jedrzejewski, R.; Kochmanska, A.E. [West Pomeranian University of Technology Szczecin, Faculty of Mechanical Engineering and Mechatronics, 19 Piastów Ave., 70-313 Szczecin (Poland); Warcholinski, B. [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland)

2015-02-27

Molybdenum carbonitride (MoCN) coatings were deposited onto HS6-5-2 steel substrate using pure Mo targets in mixed acetylene and nitrogen atmosphere by cathodic arc evaporation. The structural properties of MoCN coatings with different carbon contents (as an effect of the C{sub 2}H{sub 2} flow rate) were investigated systematically. Phase and chemical composition evolution of the coatings were characterized both by the glancing angle of X-ray diffraction (XRD) and wavelength dispersive spectrometry, respectively. These analyses have been supplemented by estimates of grain sizes and stress in the coatings. The XRD results show that the increase in acetylene flow rate causes the formation of molybdenum carbide (MoC) hexagonal phase in the coatings, a reduction of grain size and an increase in internal stress. - Highlights: • MoN and MoCN coatings were deposited by cathodic arc evaporation in nitrogen atmosphere. • MoCN coatings were formed using different acetylene flow rates. • Phase composition evolution was observed. • Crystallite size and stress were calculated.

Study on nanocomposite Ti-Al-Si-Cu-N films with various Si contents deposited by cathodic vacuum arc ion plating

Energy Technology Data Exchange (ETDEWEB)

Shi, J. [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Muders, C.M.; Kumar, A. [Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Jiang, X., E-mail: xin.jiang@uni-siegen.de [Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Pei, Z.L.; Gong, J. [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Sun, C., E-mail: csun@imr.ac.cn [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2012-10-01

Highlights: Black-Right-Pointing-Pointer XRD peaks show a tendency of decreasing intensity with increasing Si content. Black-Right-Pointing-Pointer Ti-Al-Si-Cu-N films present different microstructure with increasing Si content. Black-Right-Pointing-Pointer Films with 6 at.% Si content obtain the highest hardness, elastic modulus and H{sup 3}/E{sup 2}. Black-Right-Pointing-Pointer The wear rate decreases with an increase in hardness. - Abstract: In this study, nanocomposite Ti-Al-Si-Cu-N films were deposited on high speed steel substrates by the vacuum cathode arc ion plating (AIP) technique. By virtue of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM), the influence of silicon content on the film microstructure and characteristics was investigated systematically, including the chemical composition, crystalline structure as well as cross-section morphologies. With increasing the silicon content, a deterioration of the preferred orientation and a dense globular structure were detected. In the meanwhile, atomic force microscopy (AFM), nano-indentation, Rockwell indenter and reciprocating test were also utilized to analyze the hardness, elastic modulus, H{sup 3}/E{sup 2}, friction coefficient, adhesive strength and wear rate of the Ti-Al-Si-Cu-N films. The results showed that an optimal silicon content correlated with the best mechanical and tribological properties of the presented Ti-Al-Si-Cu-N films existed. With increasing the silicon content, the hardness, elastic modulus and the ratio H{sup 3}/E{sup 2} first were improved gradually, and then were impaired sharply again. When the silicon content reached to 6 at.%, the film possessed the highest hardness, elastic modulus and ratio H{sup 3}/E{sup 2} of approximately 24 GPa, 218 GPa and 0.31, respectively. Besides, films containing both 6 at.% and 10 at.% Si contents obtained a relatively low friction coefficient and a good adhesive

Synthesis and characterization of a novel tube-in-tube nanostructured PPy/MnO2/CNTs composite for supercapacitor

International Nuclear Information System (INIS)

Li, Juan; Que, Tingli; Huang, Jianbin

2013-01-01

Graphical abstract: A novel tube-in-tube nanostructured PPy/MnO 2 /CNTs composite have been successfully fabricated. Its inner tubules are CNTs and the outer tubules are template-synthesized PPy. Most MnO 2 nanoparticles are sandwiched between the inner and outer wall, some relatively large particles are also latched onto the outside wall of the PPy tube. The composite yields a good electrochemical reversibility through 1000 cycles’ cyclic voltammogram (CV) test and galvanostatic charge–discharge experiments at different current densities. Display Omitted Highlights: ► We fabricate a ternary organic–inorganic complex of PPy/MnO 2 /CNTs composite. ► We characterize its morphological structures and properties by several techniques. ► The composite possesses the typical tube-in-tube nanostructures. ► Most MnO 2 nanoparticles are sandwiched between the inner CNTs and outer PPy wall. ► The composite has good electrochemical reversibility for supercapacitor. -- Abstract: Ternary organic–inorganic complex of polypyrrole/manganese dioxide/carbon nanotubes (PPy/MnO 2 /CNTs) composite was prepared by in situ chemical oxidation polymerization of pyrrole in the host of inorganic matrix of MnO 2 and CNTs, using complex of methyl orange (MO)/FeCl 3 was used as a reactive self-degraded soft-template. The morphological structures of the composite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopic (HRTEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), respectively. All the results indicate that the PPy/MnO 2 /CNTs composite possesses the typical tube-in-tube nanostructures: the inner tubules are CNTs and the outer tubules are template-synthesized PPy. MnO 2 nanoparticles may either sandwich the space between the inner and outer tubules or directly latch onto the wall of the PPy tubes. The composite yields a good electrochemical

Performance of a solid oxide fuel cell with cathode containing a functional layer of LSM/YSZ film; Desempenho de uma celula a combustivel de oxido solido com catodo contendo uma camada funcional de filme LSM/YSZ

Energy Technology Data Exchange (ETDEWEB)

Pires, Filipe Oliveira; Domingues, Rosana Z.; Brant, Marcia C.; Silva, Charles L.; Matencio, Tulio [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica]. E-mail: filipequiufmg@ufmg.br

2008-07-01

Performance of a SOFC may be evaluated by using the AC-Impedance and measuring power (P V x I). The objective of this study was to compare the performance of a fuel cell with LSM as a cathode and another one containing an additional functional composite film LSM/YSZ between the LSM and YSZ. Also it was studied variation in second cell resistance and power according to the temperature, hydrogen flux and operation time. For both cells platinum was used as anode. At 800 deg C was observed, in open current circuit, when the composite layer was introduced a decrease in resistance and high power. These results show an improvement of SOFC cathode performance with the introduction of composite LSM/YSZ layer. The maximum performance of the cell was achieved with 100 mL/min hydrogen flow at 800 deg C. The experiments also showed a performance improvement at 850 deg C. The cell behavior was stable during 318 hours of test. (author)

DARHT 2 kA Cathode Development

Energy Technology Data Exchange (ETDEWEB)

Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B.; Roy, P.K.; Waldron, W.; Westenskow, G.; Yu, S.; Bieniosek, F.M.

2009-03-09

value). We reexamined all the components in the cathode region and eliminated those parts that were suspected to be potential sources of contamination, e.g., feed-throughs with zinc coating. Finally, we considered a change in the cathode type, by using a different combination of impregnation and coating. Since the ETA-II accelerator at LLNL used a 12.5 cm diameter 311XW (barium oxide doped with scandium and coated with a osmium-tungsten thin film) cathode and emitted 2200A of beam current (i.e. 18 A/cm{sup 2}), it was reasonable to assume that DARHT can adopt this type of cathode to produce 2 kA (i.e., 10A/cm{sup 2}). However, it was later found that the 311XW has a higher radiation heat loss than the 612M and therefore resulted in a maximum operating temperature (as limited by filament damage) below that required to produce the high current. With the evidence provided by systematic emission tests using quarter-inch size cathodes, we confirmed that the 311XM (doped with scandium and has a osmium-ruthenium (M) coating) had the best combination of low work function and low radiation heat loss. Subsequently a 6.5-inch diameter 311XM cathode was installed in DARHT and 2 kA beam current was obtained on June 14, 2007. In testing the quarter-inch size cathode, we found that the beam current was sensitive to the partial pressure of various gases in the vacuum chamber. Furthermore, there was a hysteresis effect on the emission as a function of temperature. The phenomenon suggested that the work function of the cathode was dependent on the dynamic equilibrium between the diffusion of the impregnated material to the surface and the contamination rate from the surrounding gas. Water vapor was found to be the worst contaminant amongst the various gases that we have tested. Our data showed that the required vacuum for emitting at 10 A/cm{sup 2} is in the low 10{sup -8} Torr range.

DARHT 2 kA Cathode Development

International Nuclear Information System (INIS)

Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B.; Roy, P.K.; Waldron, W.; Westenskow, G.; Yu, S.; Bieniosek, F.M.

2009-01-01

all the components in the cathode region and eliminated those parts that were suspected to be potential sources of contamination, e.g., feed-throughs with zinc coating. Finally, we considered a change in the cathode type, by using a different combination of impregnation and coating. Since the ETA-II accelerator at LLNL used a 12.5 cm diameter 311XW (barium oxide doped with scandium and coated with a osmium-tungsten thin film) cathode and emitted 2200A of beam current (i.e. 18 A/cm 2 ), it was reasonable to assume that DARHT can adopt this type of cathode to produce 2 kA (i.e., 10A/cm 2 ). However, it was later found that the 311XW has a higher radiation heat loss than the 612M and therefore resulted in a maximum operating temperature (as limited by filament damage) below that required to produce the high current. With the evidence provided by systematic emission tests using quarter-inch size cathodes, we confirmed that the 311XM (doped with scandium and has a osmium-ruthenium (M) coating) had the best combination of low work function and low radiation heat loss. Subsequently a 6.5-inch diameter 311XM cathode was installed in DARHT and 2 kA beam current was obtained on June 14, 2007. In testing the quarter-inch size cathode, we found that the beam current was sensitive to the partial pressure of various gases in the vacuum chamber. Furthermore, there was a hysteresis effect on the emission as a function of temperature. The phenomenon suggested that the work function of the cathode was dependent on the dynamic equilibrium between the diffusion of the impregnated material to the surface and the contamination rate from the surrounding gas. Water vapor was found to be the worst contaminant amongst the various gases that we have tested. Our data showed that the required vacuum for emitting at 10 A/cm 2 is in the low 10 -8 Torr range

Enhancing the stability and performance of a battery cathode using a non-aqueous electrolyte

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Yeol [Division of Engineering, Brown University, Providence, RI 02912 (United States); Sen, Sujat [Department of Chemistry, Brown University, Providence, RI 02912 (United States); Song, Hyun-Kon [Interdisciplinary School of Green Energy and School of Nano-Biotechnology and Chemical Engineering, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulju-gun, Ulsan 689-798 (Korea); Palmore, G. Tayhas R. [Division of Biology and Medicine, Brown University, Providence, RI 02912 (United States)

2010-06-15

For conductive polymers to be considered materials for energy storage, both their electroactivity and stability must be optimized. In this study, a non-aqueous electrolyte (0.2 M LiClO{sub 4} in acetonitrile) was studied for its effect on the charge storage capacity and stability of two materials used in batteries developed in our laboratory, polypyrrole (pPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) doped with 2,2'-azino-bis(3-ethylbenzothiaxoline-6-sulfonic acid (ABTS)). The results are compared to the performance of these materials in an aqueous electrolyte (0.2 M HCl/aq). Loss of ABTS dopant was eliminated principally due to the low solubility of ABTS in acetonitrile, resulting in cathode materials with improved stability in terms of load cycling and performance. (author)

LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

Energy Technology Data Exchange (ETDEWEB)

Harlan U. Anderson; Fatih Dogan; Vladimir Petrovsky

2002-03-31

This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. This period has continued to address the problem of making dense 1/2 to 5 {micro}m thick dense layers on porous substrates (the cathode LSM). Our current status is that we are making structures of 2-5 cm{sup 2} in area, which consist of either dense YSZ or CGO infiltrated into a 2-5 {micro}m thick 50% porous layer made of either nanoncrystalline CGO or YSZ powder. This composite structure coats a macroporous cathode or anode; which serves as the structural element of the bi-layer structure. These structures are being tested as SOFC elements. A number of structures have been evaluated both as symmetrical and as button cell configuration. Results of this testing indicates that the cathodes contribute the most to cell losses for temperatures below 750 C. In this investigation different cathode materials were studied using impedance spectroscopy of symmetric cells and IV characteristics of anode supported fuel cells. Cathode materials studied included La{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF), La{sub 0.7}Sr{sub 0.2}MnO{sub 3} (LSM), Pr{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}O{sub 3} (PSCF), Sm{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF), and Yb{sub .8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF). A new technique for filtering the Fourier transform of impedance data was used to increase the sensitivity of impedance analysis. By creating a filter specifically for impedance spectroscopy the resolution was increased. The filter was tailored to look for specific circuit elements like R//C, Warburg, or constant phase elements. As many as four peaks can be resolved using the filtering technique on symmetric cells. It may be possible to relate the different peaks to material parameters, like the oxygen exchange coefficient. The cathode grouped in order from lowest to highest ASR is

INFLUENCE OF SINTERING TEMPERATURE ON THE POLARIZATION RESISTANCE OF LaO20.6SrO20.4CoO20.2FeO20.8O3-δ - SDC CARBONATE COMPOSITE CATHODE

Directory of Open Access Journals (Sweden)

Nurul Akidah Baharuddin

2016-05-01

Full Text Available The effects of sintering temperature of an LSCF-samarium-doped ceria carbonate (SDCC cathode composite film on its polarization resistance (Rp were evaluated in this study. An LSCF-SDCC composite cathode was prepared for cathode film development by electrophoretic deposition (EPD. The LSCF-SDCC composite cathode was prepared at 50:50 weight percentage ratio. An EPD suspension which is based on an organic aqueous solution was used, and a mixture of ethanol and deionized water was used as medium with poly diallyl dimethyl ammonium chloride (PDADMAC as a dispersing agent. SDCC substrate was used, and EPD was performed on both sides. A symmetrical cell with cathode composite LSCF-SDCC films on both sides of the substrate was subjected to sintering at five different temperatures (from 550°C to 750°C. A symmetrical cell was painted using silver paste before undergoing electrochemical performance test (air condition, in which the impedance, Z data, was measured. The effects of sintering temperature change on element content and film porosity were first investigated by energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, and J-image analysis. Ceramic-based cathode LSCF-SDCC that was sintered at 600°C exhibited the lowest Rp at a value of 0.68 Ω when operated at 650°C. This study proved that EPD has potential in developing IT-LT solid oxide fuel cell cathode components with high electrochemical performance in terms of Rp values.

Dimethylacetamide as a film-forming additive for improving the cyclic stability of high voltage lithium-rich cathode at room and elevated temperature

International Nuclear Information System (INIS)

Tu, Wenqiang; Xing, Lidan; Xia, Pan; Xu, Mengqing; Liao, Youhao; Li, Weishan

2016-01-01

Highlights: • Addition of 1% DMAc improves the cyclic performances of LLO at room and elevated temperature. • DMAc oxidizes previously to the STD electrolyte and generates a protective film on the LLO surface. • The protective film is thin and uniform. - Abstract: In this work, dimethylacetamide (DMAc) was investigated as an electrolyte film-forming additive to improve the cyclic stability of high voltage Lithium-rich layered nickel manganese cobalt oxide (LLO) cathode at room (25 °C) and elevated (55 °C) temperature. At 0.5C rate, addition of 1% DMAc slightly decreases the initial discharge capacity of LLO from 187 to 179 mAh g −1 at room temperature and 255 to 246 mAh g −1 at elevated temperature, while significantly improves the capacity retention of LLO from 65.8% to 80.2% after 200 cycles at room temperature and from 21.1% to 66.7% after 150 cycles at elevated temperature. The mechanism of DMAc improving the cyclic stability of LLO was investigated via theoretical calculation and experimental characterizations, which demonstrated that DMAc oxidized preferential to the STD (1.0 M LiPF 6 in a mixed solvent of ethylene carbonate/ethyl methyl carbonate/diethyl carbonate) electrolyte, generating a thin and uniform film on the LLO surface. This film effectively suppresses the subsequent decomposition of STD electrolyte and further degradation of spinel phase converted from the layered structure of LLO, resulting in improved cyclic stability of LLO at room and elevated temperature.

Co nanoparticles induced resistive switching and magnetism for the electrochemically deposited polypyrrole composite films.

Science.gov (United States)

Xu, Zedong; Gao, Min; Yu, Lina; Lu, Liying; Xu, Xiaoguang; Jiang, Yong

2014-10-22

The resistive switching behavior of Co-nanoparticle-dispersed polypyrrole (PPy) composite films is studied. A novel design method for resistive random access memory (ReRAM) is proposed. The conducting polymer films with metal nanocrystal (NC)-dispersed carbon chains induce the spontaneous oxidization of the conducting polymer at the surface. The resistive switching behavior is achieved by an electric field controlling the oxygen ion mobility between the metal electrode and the conducting polymer film to realize the mutual transition between intrinsic conduction (low resistive state) and oxidized layer conduction (high resistive state). Furthermore, the formation process of intrinsic conductive paths can be effectively controlled in the conducting polymer ReRAM using metal NCs in films because the inner metal NCs induce electric field lines converging around them and the intensity of the electric field at the tip of NCs can greatly exceed that of the other region. Metal NCs can also bring new characteristics for ReRAM, such as magnetism by dispersing magnetic metal NCs in polymer, to obtain multifunctional electronic devices or meet some special purpose in future applications. Our works will enrich the application fields of the electromagnetic PPy composite films and present a novel material for ReRAM devices.

A "Tandem" Strategy to Fabricate Flexible Graphene/Polypyrrole Nanofiber Film Using the Surfactant-Exfoliated Graphene for Supercapacitors.

Science.gov (United States)

Shu, Kewei; Chao, Yunfeng; Chou, Shulei; Wang, Caiyun; Zheng, Tian; Gambhir, Sanjeev; Wallace, Gordon G

2018-06-19

The surfactant-assisted liquid-phase exfoliation of expanded graphite can produce graphene sheets in large quantities with minimal defects. However, it is difficult to completely remove the surfactant from the final product, thus affecting the electrochemical properties of the produced graphene. In this article, a novel approach to fabricate flexible graphene/polypyrrole film was developed: using surfactant cetyltrimethylammonium bromide as a template for growth of polypyrrole nanofibers (PPyNFs) instead of removal after the exfoliation process; followed by a simple filtration method. The introduction of PPyNF not only increases the electrochemical performance, but also ensures flexibility. This composite film electrode offers a capacitance up to 161 F g -1 along with a capacitance retention rate of over 80% after 5000 cycles.

Bio-inspired Construction of Advanced Fuel Cell Cathode with Pt Anchored in Ordered Hybrid Polymer Matrix.

Science.gov (United States)

Xia, Zhangxun; Wang, Suli; Jiang, Luhua; Sun, Hai; Liu, Shuang; Fu, Xudong; Zhang, Bingsen; Sheng Su, Dang; Wang, Jianqiang; Sun, Gongquan

2015-11-05

The significant use of platinum for catalyzing the cathodic oxygen reduction reactions (ORRs) has hampered the widespread use of polymer electrolyte membrane fuel cells (PEMFCs). The construction of well-defined electrode architecture in nanoscale with enhanced utilization and catalytic performance of Pt might be a promising approach to address such barrier. Inspired by the highly efficient catalytic processes in enzymes with active centers embedded in charge transport pathways, here we demonstrate for the first time a design that allocates platinum nanoparticles (Pt NPs) at the boundaries with dual-functions of conducting both electrons by aid of polypyrrole and protons via Nafion(®) ionomer within hierarchical nanoarrays. By mimicking enzymes functionally, an impressive ORR activity and stability is achieved. Using this brand new electrode architecture as the cathode and the anode of a PEMFC, a high mass specific power density of 5.23 W mg(-1)Pt is achieved, with remarkable durability. These improvements are ascribed to not only the electron decoration and the anchoring effects from the Nafion(®) ionomer decorated PPy substrate to the supported Pt NPs, but also the fast charge and mass transport facilitated by the electron and proton pathways within the electrode architecture.

Porous La_0.6Sr_0.4CoO_3-δ thin film cathodes for large area micro solid oxide fuel cell power generators

DEFF Research Database (Denmark)

Garbayo, A.; Esposito, Vincenzo; Sanna, Simone

2014-01-01

Porous La0.6Sr0.4CoO3-δ thin films were fabricated by pulsed laser deposition for being used as a cathode for micro solid oxide fuel cell applications as MEMS power generators. Symmetrical La0.6Sr0.4CoO3-δ/ yttria-stabilized zirconia/La0.6Sr0.4CoO3-δ free-standing membranes were fabricated using ...

Metal-oxide-junction, triple point cathodes in a relativistic magnetron

International Nuclear Information System (INIS)

Jordan, N. M.; Gilgenbach, R. M.; Hoff, B. W.; Lau, Y. Y.

2008-01-01

Triple point, defined as the junction of metal, dielectric, and vacuum, is the location where electron emission is favored in the presence of a sufficiently strong electric field. To exploit triple point emission, metal-oxide-junction (MOJ) cathodes consisting of dielectric ''islands'' over stainless steel substrates have been fabricated. The two dielectrics used are hafnium oxide (HfO x ) for its high dielectric constant and magnesium oxide (MgO) for its high secondary electron emission coefficient. The coatings are deposited by ablation-plasma-ion lithography using a KrF laser (0-600 mJ at 248 nm) and fluence ranging from 3 to 40 J/cm 2 . Composition and morphology of deposited films are analyzed by scanning electron microscopy coupled with x-ray energy dispersive spectroscopy, as well as x-ray diffraction. Cathodes are tested on the Michigan Electron Long-Beam Accelerator with a relativistic magnetron, at parameters V=-300 kV, I=1-15 kA, and pulse lengths of 0.3-0.5 μs. Six variations of the MOJ cathode are tested, and are compared against five baseline cases. It is found that particulate formed during the ablation process improves the electron emission properties of the cathodes by forming additional triple points. Due to extensive electron back bombardment during magnetron operation, secondary electron emission also may play a significant role. Cathodes exhibit increases in current densities of up to 80 A/cm 2 , and up to 15% improvement in current start up time, as compared to polished stainless steel cathodes

Cathode Readout with Stripped Resistive Drift Tubes

International Nuclear Information System (INIS)

Bychkov, V.N.; Kekelidze, G.D.; Novikov, E.A.; Peshekhonov, V.D.; Shafranov, M.D.; Zhil'tsov, V.E.

1994-01-01

A straw tube drift chamber prototype has been constructed and tested. The straw tube material is mylar film covered with carbon layer of resistivity 0.5, 30 and 70 k Ohm/sq. The gas mixture used was Ar/CH 4 . Both the anode wire and cathode signals were detected in order to study the behaviour of the chamber in the presence of X-ray ionization. The construction and the results of the study are presented. 7 refs., 11 figs., 1 tab

Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2010-01-15

We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

Facile synthesis of polypyrrole functionalized nickel foam with catalytic activity comparable to Pt for the poly-generation of hydrogen and electricity

Science.gov (United States)

Tang, Tiantian; Li, Kan; Shen, Zhemin; Sun, Tonghua; Wang, Yalin; Jia, Jinping

2016-01-01

Polypyrrole functionalized nickel foam is facilely prepared through the potentiostatic electrodeposition. The PPy-functionalized Ni foam functions as a hydrogen-evolution cathode in a rotating disk photocatalytic fuel cell, in which hydrogen energy and electric power are generated by consuming organic wastes. The PPy-functionalized Ni foam cathode exhibits stable catalytic activities after thirteen continuous runs. Compared with net or plate structure, the Ni foam with a unique three-dimensional reticulate structure is conducive to the electrodeposition of PPy. Compared with Pt-group electrode, PPy-coated Ni foam shows a satisfactory catalytic performance for the H2 evolution. The combination of PPy and Ni forms a synergistic effect for the rapid trapping and removal of proton from solution and the catalytic reduction of proton to hydrogen. The PPy-functionalized Ni foam could be applied in photocatalytic and photoelectrochemical generation of H2. In all, we report a low cost, high efficient and earth abundant PPy-functionalized Ni foam with a satisfactory catalytic activities comparable to Pt for the practical application of poly-generation of hydrogen and electricity.

Self-powered vision electronic-skin basing on piezo-photodetecting Ppy/PVDF pixel-patterned matrix for mimicking vision

Science.gov (United States)

Han, Wuxiao; Zhang, Linlin; He, Haoxuan; Liu, Hongmin; Xing, Lili; Xue, Xinyu

2018-06-01

The development of multifunctional electronic-skin that establishes human-machine interfaces, enhances perception abilities or has other distinct biomedical applications is the key to the realization of artificial intelligence. In this paper, a new self-powered (battery-free) flexible vision electronic-skin has been realized from pixel-patterned matrix of piezo-photodetecting PVDF/Ppy film. The electronic-skin under applied deformation can actively output piezoelectric voltage, and the outputting signal can be significantly influenced by UV illumination. The piezoelectric output can act as both the photodetecting signal and electricity power. The reliability is demonstrated over 200 light on–off cycles. The sensing unit matrix of 6 × 6 pixels on the electronic-skin can realize image recognition through mapping multi-point UV stimuli. This self-powered vision electronic-skin that simply mimics human retina may have potential application in vision substitution.

Self-powered vision electronic-skin basing on piezo-photodetecting Ppy/PVDF pixel-patterned matrix for mimicking vision.

Science.gov (United States)

Han, Wuxiao; Zhang, Linlin; He, Haoxuan; Liu, Hongmin; Xing, Lili; Xue, Xinyu

2018-06-22

The development of multifunctional electronic-skin that establishes human-machine interfaces, enhances perception abilities or has other distinct biomedical applications is the key to the realization of artificial intelligence. In this paper, a new self-powered (battery-free) flexible vision electronic-skin has been realized from pixel-patterned matrix of piezo-photodetecting PVDF/Ppy film. The electronic-skin under applied deformation can actively output piezoelectric voltage, and the outputting signal can be significantly influenced by UV illumination. The piezoelectric output can act as both the photodetecting signal and electricity power. The reliability is demonstrated over 200 light on-off cycles. The sensing unit matrix of 6 × 6 pixels on the electronic-skin can realize image recognition through mapping multi-point UV stimuli. This self-powered vision electronic-skin that simply mimics human retina may have potential application in vision substitution.

Synthesis and characterization of a novel tube-in-tube nanostructured PPy/MnO{sub 2}/CNTs composite for supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Li, Juan, E-mail: lj-panpan@163.com [College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046 (China); Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Que, Tingli [College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046 (China); Huang, Jianbin, E-mail: JBhuang@pku.edu.cn [College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046 (China); Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

2013-02-15

Graphical abstract: A novel tube-in-tube nanostructured PPy/MnO{sub 2}/CNTs composite have been successfully fabricated. Its inner tubules are CNTs and the outer tubules are template-synthesized PPy. Most MnO{sub 2} nanoparticles are sandwiched between the inner and outer wall, some relatively large particles are also latched onto the outside wall of the PPy tube. The composite yields a good electrochemical reversibility through 1000 cycles’ cyclic voltammogram (CV) test and galvanostatic charge–discharge experiments at different current densities. Display Omitted Highlights: ► We fabricate a ternary organic–inorganic complex of PPy/MnO{sub 2}/CNTs composite. ► We characterize its morphological structures and properties by several techniques. ► The composite possesses the typical tube-in-tube nanostructures. ► Most MnO{sub 2} nanoparticles are sandwiched between the inner CNTs and outer PPy wall. ► The composite has good electrochemical reversibility for supercapacitor. -- Abstract: Ternary organic–inorganic complex of polypyrrole/manganese dioxide/carbon nanotubes (PPy/MnO{sub 2}/CNTs) composite was prepared by in situ chemical oxidation polymerization of pyrrole in the host of inorganic matrix of MnO{sub 2} and CNTs, using complex of methyl orange (MO)/FeCl{sub 3} was used as a reactive self-degraded soft-template. The morphological structures of the composite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopic (HRTEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), respectively. All the results indicate that the PPy/MnO{sub 2}/CNTs composite possesses the typical tube-in-tube nanostructures: the inner tubules are CNTs and the outer tubules are template-synthesized PPy. MnO{sub 2} nanoparticles may either sandwich the space between the inner and outer tubules or directly latch onto the wall of the PPy tubes. The composite

Properties of nanostructured undoped ZrO{sub 2} thin film electrolytes by plasma enhanced atomic layer deposition for thin film solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Cho, Gu Young; Noh, Seungtak; Lee, Yoon Ho; Cha, Suk Won, E-mail: ybkim@hanyang.ac.kr, E-mail: swcha@snu.ac.kr [Department of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, Iui-dong, Yeongtong-gu, Suwon 443-270 (Korea, Republic of); Hong, Soon Wook; Koo, Bongjun; Kim, Young-Beom, E-mail: ybkim@hanyang.ac.kr, E-mail: swcha@snu.ac.kr [Department of Mechanical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); An, Jihwan [Manufacturing Systems and Design Engineering Programme, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of)

2016-01-15

Nanostructured ZrO{sub 2} thin films were prepared by thermal atomic layer deposition (ALD) and by plasma-enhanced atomic layer deposition (PEALD). The effects of the deposition conditions of temperature, reactant, plasma power, and duration upon the physical and chemical properties of ZrO{sub 2} films were investigated. The ZrO{sub 2} films by PEALD were polycrystalline and had low contamination, rough surfaces, and relatively large grains. Increasing the plasma power and duration led to a clear polycrystalline structure with relatively large grains due to the additional energy imparted by the plasma. After characterization, the films were incorporated as electrolytes in thin film solid oxide fuel cells, and the performance was measured at 500 °C. Despite similar structure and cathode morphology of the cells studied, the thin film solid oxide fuel cell with the ZrO{sub 2} thin film electrolyte by the thermal ALD at 250 °C exhibited the highest power density (38 mW/cm{sup 2}) because of the lowest average grain size at cathode/electrolyte interface.

Preparation and characterization of electronically conducting polypyrrole-montmorillonite nanocomposite and its potential application as a cathode material for oxygen reduction

International Nuclear Information System (INIS)

Rajapakse, R.M.G.; Murakami, Kenji; Bandara, H.M.N.; Rajapakse, R.M.M.Y.; Velauthamurti, K.; Wijeratne, S.

2010-01-01

Simple wet chemical processes were deployed to prepare low-cost conducting nanocomposites based on natural clays with 2:1 layered structures such as sodium montmorillonite (MMT). Ce(IV) modified MMT was used for the spontaneous polymerization of pyrrole within clay interlayers. The resulted clay-conducting polypyrrole nanocomposites containing the reduced form of the oxidising agent, have been extensively characterized by X-ray diffraction (XRD) technique for interlayer spacing variations and by Fourier transform infra red (FT-IR) spectroscopy to study the interactions between the clay and polymer functional groups. DC polarization technique with both blocking and non-blocking electrodes was used to distinguish between the ionic and electronic transport numbers and to recognize the type of mobile ionic species. AC impedance analysis further resolved the electrical conduction of these materials. Bulk conductivity analysis implied that the polypyrrole (PPY) formed within Ce(IV) modified MMT posses dominant electronic conductivity. The low-cost, light-weight and stable polymer-clay nanocomposite prepared by Ce(IV) intercalated MMT, [Ce(III)-PPY-MMT], seems to be a promising cathode material for oxygen reduction and hence may find applications in fuel cell industries.

Regression Analysis of the Effect of Bias Voltage on Nano- and Macrotribological Properties of Diamond-Like Carbon Films Deposited by a Filtered Cathodic Vacuum Arc Ion-Plating Method

Directory of Open Access Journals (Sweden)

Shojiro Miyake

2014-01-01

Full Text Available Diamond-like carbon (DLC films are deposited by bend filtered cathodic vacuum arc (FCVA technique with DC and pulsed bias voltage. The effects of varying bias voltage on nanoindentation and nanowear properties were evaluated by atomic force microscopy. DLC films deposited with DC bias voltage of −50 V exhibited the greatest hardness at approximately 50 GPa, a low modulus of dissipation, low elastic modulus to nanoindentation hardness ratio, and high nanowear resistance. Nanoindentation hardness was positively correlated with the Raman peak ratio Id/Ig, whereas wear depth was negatively correlated with this ratio. These nanotribological properties highly depend on the films’ nanostructures. The tribological properties of the FCVA-DLC films were also investigated using a ball-on-disk test. The average friction coefficient of DLC films deposited with DC bias voltage was lower than that of DLC films deposited with pulse bias voltage. The friction coefficient calculated from the ball-on-disk test was correlated with the nanoindentation hardness in dry conditions. However, under boundary lubrication conditions, the friction coefficient and specific wear rate had little correlation with nanoindentation hardness, and wear behavior seemed to be influenced by other factors such as adhesion strength between the film and substrate.

Operando and in situ X-ray spectroscopies of degradation in La0.6Sr0.4Co0.2Fe0.8O(3-δ) thin film cathodes in fuel cells.

Science.gov (United States)

Lai, Samson Y; Ding, Dong; Liu, Mingfei; Liu, Meilin; Alamgir, Faisal M

2014-11-01

Information from ex situ characterization can fall short in describing complex materials systems simultaneously exposed to multiple external stimuli. Operando X-ray absorption spectroscopy (XAS) was used to probe the local atomistic and electronic structure of specific elements in a La0.6Sr0.4Co0.2Fe0.8O(3-δ) (LSCF) thin film cathode exposed to air contaminated with H2O and CO2 under operating conditions. While impedance spectroscopy showed that the polarization resistance of the LSCF cathode increased upon exposure to both contaminants at 750 °C, XAS near-edge and extended fine structure showed that the degree of oxidation for Fe and Co decreases with increasing temperature. Synchrotron-based X-ray photoelectron spectroscopy tracked the formation and removal of a carbonate species, a Co phase, and different oxygen moieties as functions of temperature and gas. The combined information provides insight into the fundamental mechanism by which H2O and CO2 cause degradation in the cathode of solid oxide fuel cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fundamental aspects of cathodic sputtering

International Nuclear Information System (INIS)

Harman, R.

1979-01-01

The main fundamental aspects and problems of cathodic sputtering used mainly for thin film deposition and sputter etching are discussed. Among many types of known sputtering techniques the radiofrequency /RF/ diode sputtering is the most universal one and is used for deposition of metals, alloys, metallic compounds, semiconductors and insulators. It seems that nowadays the largest number of working sputtering systems is of diode type. Sometimes also the dc or rf triode sputtering systems are used. The problems in these processes are practically equivalent and comparable with the problems in the diode method and therefore our discussion will be, in most cases applicable for both, the diode and triode methods

Three-dimensional (3D α-Fe2O3/polypyrrole (PPy nanocomposite for effective electromagnetic absorption

Directory of Open Access Journals (Sweden)

Wanchun Jiang

2016-06-01

Full Text Available The lightweight and 3-dimensional reticulated α-Fe2O3/PPy hybrids were successfully fabricated via a facile one-pot polyreaction. The measured complex permittivity and microwave attenuation performance suggest that the dielectric properties of PPy can be regulated by the mass ratio of added α-Fe2O3. The two dielectric resonance peaks of complex permittivity can be ascribed to the interface capacitor-like structure. An equivalent circuit model was established to explain the nonlinear resonance behavior of the α-Fe2O3/PPy wax composites. The addition of α-Fe2O3 properly tuned the dielectric constant to endow the composites with highly efficient microwave absorption. The minimum reflection loss of α-Fe2O3/PPy wax composites were enhanced to nearly −29dB with an effective bandwidth (RL≤ − 10dB up to 5.0GHz. The numerical method was proposed to calculate the optimum thickness for minimum RL at expected frequency by detailed investigation on the transmission formula. Moreover, the required thickness for optimum absorption efficiency at expected frequency can be obtained directly.

Controllable Spatial Configuration on Cathode Interface for Enhanced Photovoltaic Performance and Device Stability.

Science.gov (United States)

Li, Jiangsheng; Duan, Chenghao; Wang, Ning; Zhao, Chengjie; Han, Wei; Jiang, Li; Wang, Jizheng; Zhao, Yingjie; Huang, Changshui; Jiu, Tonggang

2018-05-08

The molecular structure of cathode interface modification materials can affect the surface morphology of the active layer and key electron transfer processes occurring at the interface of polymer solar cells in inverted structures mostly due to the change of molecular configuration. To investigate the effects of spatial configuration of the cathode interfacial modification layer on polymer solar cells device performances, we introduced two novel organic ionic salts (linear NS2 and three-dimensional (3D) NS4) combined with the ZnO film to fabricate highly efficient inverted solar cells. Both organic ionic salts successfully decreased the surface traps of the ZnO film and made its work function more compatible. Especially NS4 in three-dimensional configuration increased the electron mobility and extraction efficiency of the interfacial film, leading to a significant improvement of device performance. Power conversion efficiency (PCE) of 10.09% based on NS4 was achieved. Moreover, 3D interfacial modification could retain about 92% of its initial PCE over 160 days. It is proposed that 3D interfacial modification retards the element penetration-induced degradation without impeding the electron transfer from the active layer to the ZnO film, which significantly improves device stability. This indicates that inserting three-dimensional organic ionic salt is an efficient strategy to enhance device performance.

Reflux parameters as modified by laparoscopic fundoplication in 40 patients with heartburn/regurgitation persisting despite PPI therapy: a study using impedance-pH monitoring.

Science.gov (United States)

Frazzoni, Marzio; Conigliaro, Rita; Melotti, Gianluigi

2011-04-01

Patients with typical reflux symptoms (heartburn/regurgitation) persisting despite proton pump inhibitor (PPI) therapy are not uncommon. Impedance-pH monitoring detects gastroesophageal reflux at all pH levels and may establish if ongoing symptoms on PPI therapy are associated with acid/nonacid reflux. Laparoscopic fundoplication is a therapeutic option in such patients but reflux parameters on PPI therapy and after intervention and their relationship with symptom persistence/remission have been scarcely studied. The aim of this study was to assess reflux parameters and their relationship with symptoms before and after laparoscopic fundoplication, on and off PPI therapy, respectively, in patients with PPI-unresponsive heartburn/regurgitation and with a positive symptom-reflux association and/or abnormal reflux parameters detected on PPI therapy. Impedance-pH monitoring was performed on high-dose PPI therapy and 3 months after laparoscopic fundoplication, off PPI therapy, in 40 patients with PPI-unresponsive heartburn/regurgitation. Symptoms were scored by a validated questionnaire. Esophageal acid exposure time as well as the number of total and proximal reflux events and of acid and weakly acidic refluxes decreased significantly after surgery: normal values were found in 100, 77, 95, 92 and 65% of cases, respectively. Weakly alkaline refluxes increased significantly postoperatively but neither before nor after intervention were associated with symptoms. All patients reported total/subtotal remission of heartburn/regurgitation 3 months after surgery. Laparoscopic fundoplication improves acid and weakly acidic reflux parameters when compared with PPI therapy. This improvement justifies the very high post-surgical symptom remission rate that we observed. Prolonged follow-up is warranted but our findings strongly support the surgical option in PPI failures.

Carbon nanowalls in field emission cathodes

Directory of Open Access Journals (Sweden)

Belyanin A. F.

2017-12-01

Full Text Available The carbon nanowall (CNW layers were grown from a gas mixture of hydrogen and methane, activated by a DC glow discharge, on Si substrates (Si/CNW layered structure. The second layer of CNW was grown either on the first layer (Si/CNW/CNW structure or on Ni or NiO films deposited on the first CNW layer (Si/CNW/Ni/CNW and Si/CNW/NiO/CNW structures. The composition and structure of the resulting layered structures were studied using scanning electron microscopy, Raman spectroscopy, and X-ray diffractometry. It was found that annealing of Si/CNW structure in vacuum, growing of the second CNW layer on Si/CNW, as well as deposition of Ni or NiO films prior to the growing of the second CNW layer improve functional properties of field emission cathodes based on the electron-emitting CNW layers.

Fabrication and characterization of a cathode-supported tubular solid oxide fuel cell

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wang, Zhenrong; Qian, Jiqin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2009-07-15

A cathode-supported tubular solid oxide fuel cell (CTSOFC) with the length of 6.0 cm and outside diameter of 1.0 cm has been successfully fabricated via dip-coating and co-sintering techniques. A crack-free electrolyte film with a thickness of {proportional_to}14 {mu}m was obtained by co-firing of cathode/cathode active layer/electrolyte/anode at 1250 C. The relative low densifying temperature for electrolyte was attributed to the large shrinkage of the green tubular which assisted the densification of electrolyte. The assembled cell was electrochemically characterized with humidified H{sub 2} as fuel and O{sub 2} as oxidant. The open circuit voltages (OCV) were 1.1, 1.08 and 1.06 V at 750, 800 and 850 C, respectively, with the maximum power densities of 157, 272 and 358 mW cm{sup -2} at corresponding temperatures. (author)

Optical Properties and Electrochemical Performance of LiFePO4 Thin Films Deposited on Transparent Current Collectors.

Science.gov (United States)

Lee, HyunSeok; Yim, Haena; Kim, Kwang-Bum; Choi, Ji-Won

2015-11-01

LiFePO4 thin film cathodes are deposited on various transparent conducting oxide thin films on glass, which are used as cathode current collectors. The XRD patterns show that the thin films have the phase of LiFePO4 with an ordered olivine structure indexed to the orthorhombic Pmna space group. LiFePO4 thin film deposited on various TCO glass substrates exhibits transmittance of about 53%. The initial specific discharge capacities of LiFePO4 thin films are 25.0 μAh/cm2 x μm on FTO, 33.0 μAh/cm2 x μm on ITO, and 13.0 μAh/cm2 x μm on AZO coated glass substrates. Interestingly, the retention capacities of LiFePO4 thin films are 76.0% on FTO, 31.2% on ITO, and 37.7% on AZO coated glass substrates at 20th cycle. The initial specific discharge capacity of the LiFePO4/FTO electrode is slightly lower, but the discharge capacities of the LiFePO4/FTO electrode relatively decrease less than those of the others such as LiFePO4/ITO and LiFePO4/AZO with cycling. The results reported here provide the high transparency of LiFePO4 thin films cathode materials and the good candidate as FTO current collector of the LiFePO4 thin film cathode of transparent thin film rechargeable batteries due to its high transparency and cyclic retention.

Direct electrochemistry of glucose oxidase on novel free-standing nitrogen-doped carbon nanospheres@carbon nanofibers composite film.

Science.gov (United States)

Zhang, Xueping; Liu, Dong; Li, Libo; You, Tianyan

2015-05-06

We have proposed a novel free-standing nitrogen-doped carbon nanospheres@carbon nanofibers (NCNSs@CNFs) composite film with high processability for the investigation of the direct electron transfer (DET) of glucose oxidase (GOx) and the DET-based glucose biosensing. The composites were simply prepared by controlled thermal treatment of electrospun polypyrrole nanospheres doped polyacrylonitrile nanofibers (PPyNSs@PAN NFs). Without any pretreatment, the as-prepared material can directly serve as a platform for GOx immobilization. The cyclic voltammetry of immobilized GOx showed a pair of well-defined redox peaks in O2-free solution, indicating the DET of GOx. With the addition of glucose, the anodic peak current increased, while the cathodic peak current decreased, which demonstrated the DET-based bioelectrocatalysis. The detection of glucose based on the DET of GOx was achieved, which displayed high sensitivity, stability and selectivity, with a low detection limit of 2 μM and wide linear range of 12-1000 μM. These results demonstrate that the as-obtained NCNSs@CNFs can serve as an ideal platform for the construction of the third-generation glucose biosensor.

Selective Phosphonylation of 5'-Adenosine Monophosphate (5'-AMP) via Pyrophosphite [PPi(III)].

Science.gov (United States)

Kaye, Karl; Bryant, David E; Marriott, Katie E R; Ohara, Shohei; Fishwick, Colin W G; Kee, Terence P

2016-11-01

We describe here experiments which demonstrate the selective phospho-transfer from a plausibly prebiotic condensed phosphorus (P) salt, pyrophosphite [H 2 P 2 O 5 2- ; PPi(III)], to the phosphate group of 5'-adenosine mono phosphate (5'-AMP). We show further that this P-transfer process is accelerated both by divalent metal ions (M 2+ ) and by organic co-factors such as acetate (AcO - ). In this specific case of P-transfer from PPi(III) to 5'-AMP, we show a synergistic enhancement of transfer in the combined presence of M 2+ & AcO - . Isotopic labelling studies demonstrate that hydrolysis of the phosphonylated 5'-AMP, [P(III)P(V)-5'-AMP], proceeds via nuceophilic attack of water at the Pi(III) terminus.

Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

Science.gov (United States)

Lo, Momath; Diaw, Abdou K D; Gningue-Sall, Diariatou; Aaron, Jean-Jacques; Oturan, Mehmet A; Chehimi, Mohamed M

2018-05-09

Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb 2+ , Cu 2+ , and Cd 2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu 2+ , Cd 2+ , and Pb 2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99 nM for Cu 2+ , Cd 2+ , and Pb 2+ , respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

Capacity Fade Analysis of Sulfur Cathodes in Lithium–Sulfur Batteries

Science.gov (United States)

Yan, Jianhua; Liu, Xingbo

2016-01-01

Rechargeable lithium–sulfur (Li–S) batteries are receiving ever‐increasing attention due to their high theoretical energy density and inexpensive raw sulfur materials. However, their rapid capacity fade has been one of the key barriers for their further improvement. It is well accepted that the major degradation mechanisms of S‐cathodes include low electrical conductivity of S and sulfides, precipitation of nonconductive Li2S2 and Li2S, and poly‐shuttle effects. To determine these degradation factors, a comprehensive study of sulfur cathodes with different amounts of electrolytes is presented here. A survey of the fundamentals of Li–S chemistry with respect to capacity fade is first conducted; then, the parameters obtained through electrochemical performance and characterization are used to determine the key causes of capacity fade in Li–S batteries. It is confirmed that the formation and accumulation of nonconductive Li2S2/Li2S films on sulfur cathode surfaces are the major parameters contributing to the rapid capacity fade of Li–S batteries. PMID:27981001

Preparation of PPy-Coated MnO2 Hybrid Micromaterials and Their Improved Cyclic Performance as Anode for Lithium-Ion Batteries.

Science.gov (United States)

Feng, Lili; Zhang, Yinyin; Wang, Rui; Zhang, Yanli; Bai, Wei; Ji, Siping; Xuan, Zhewen; Yang, Jianhua; Zheng, Ziguang; Guan, Hongjin

2017-09-02

MnO 2 @PPy core-shell micromaterials are prepared by chemical polymerization of pyrrole on the MnO 2 surface. The polypyrrole (PPy) is formed as a homogeneous organic shell on the MnO 2 surface. The thickness of PPy shell can be adjusted by the usage of pyrrole. The analysis of SEM, FT-IR, X-ray photoelectron spectroscopy (XPS), thermo-gravimetric analysis (TGA), and XRD are used to confirm the formation of PPy shell. Galvanostatic cell cycling and electrochemical impedance spectroscopy (EIS) are used to evaluate the electrochemical performance as anode for lithium-ion batteries. The results show that after formation of MnO 2 @PPy core-shell micromaterials, the cyclic performance as anode for lithium-ion batteries is improved. Fifty microliters of PPy-coated caddice-clew-like MnO 2 has the best cyclic performances as has 620 mAh g -1 discharge specific capacities after 300 cycles. As a comparison, the discharge specific capacity of bare MnO 2 materials falls to below 200 mAh g -1 after 10 cycles. The improved lithium-storage cyclic stability of the MnO 2 @PPy samples attributes to the core-shell hybrid structure which can buffer the structural expansion and contraction of MnO 2 caused by the repeated embedding and disengagement of Li ions and can prevent the pulverization of MnO 2 . This experiment provides an effective way to mitigate the problem of capacity fading of the transition metal oxide materials as anode materials for (lithium-ion batteries) LIBs.

Studying the initial stages of film electrodeposition of magnetic cobalt-tungsten alloys

International Nuclear Information System (INIS)

Rachinskas, V.S.; Orlovskaya, L.V.; Parfenov, V.A.; Yasulajtene, V.V.

1996-01-01

Initial stages of magnetic film electrodeposition by recording potentiodynamic polarization and j c ,t-curves, determination of surface structure of electrolytically deposited films by the method of XPS and study of thin coating properties have been considered. It is shown that at initial stage of electrodeposition of magnetic Co-W-films a sharp decrease in cathode process rate and formation of Co(OH) 2 , WO 3 and/or WO 4 2- occur on Cu-cathode surface. Electrodeposition of metallic magnetic Co-W-alloy, consisting of Co, W and containing basic compounds of co-deposited metals, takes place after a certain time period depending on deposition E c . 6 refs.; 3 figs

The Arabidopsis ppi1 Mutant Is Specifically Defective in the Expression, Chloroplast Import, and Accumulation of Photosynthetic ProteinsW⃞

Science.gov (United States)

Kubis, Sybille; Baldwin, Amy; Patel, Ramesh; Razzaq, Azam; Dupree, Paul; Lilley, Kathryn; Kurth, Joachim; Leister, Dario; Jarvis, Paul

2003-01-01

The import of nucleus-encoded proteins into chloroplasts is mediated by translocon complexes in the envelope membranes. A component of the translocon in the outer envelope membrane, Toc34, is encoded in Arabidopsis by two homologous genes, atTOC33 and atTOC34. Whereas atTOC34 displays relatively uniform expression throughout development, atTOC33 is strongly upregulated in rapidly growing, photosynthetic tissues. To understand the reason for the existence of these two related genes, we characterized the atTOC33 knockout mutant ppi1. Immunoblotting and proteomics revealed that components of the photosynthetic apparatus are deficient in ppi1 chloroplasts and that nonphotosynthetic chloroplast proteins are unchanged or enriched slightly. Furthermore, DNA array analysis of 3292 transcripts revealed that photosynthetic genes are moderately, but specifically, downregulated in ppi1. Proteome differences in ppi1 could be correlated with protein import rates: ppi1 chloroplasts imported the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit and 33-kD oxygen-evolving complex precursors at significantly reduced rates, but the import of a 50S ribosomal subunit precursor was largely unaffected. The ppi1 import defect occurred at the level of preprotein binding, which is consistent with a role for atToc33 during preprotein recognition. The data suggest that atToc33 is involved preferentially in the import of photosynthetic proteins and, by extension, that atToc34 is involved in the import of nonphotosynthetic chloroplast proteins. PMID:12897258

Thermal Conductivity Changes Due to Degradation of Cathode Film Subjected to Charge-Discharge Cycles in a Li Ion Battery

Science.gov (United States)

Jagannadham, K.

2018-05-01

A battery device with graphene platelets as anode, lithium nickel manganese oxide as cathode, and solid-state electrolyte consisting of layers of lithium phosphorous oxynitride and lithium lanthanum titanate is assembled on the stainless steel substrate. The battery in a polymer enclosure is subjected to several electrical tests consisting of charge and discharge cycles at different current and voltage levels. Thermal conductivity of the cathode layer is determined at the end of charge-discharge cycles using transient thermoreflectance. The microstructure and composition of the cathode layer and the interface between the cathode, the anode, and the electrolyte are characterized using scanning electron microscopy and elemental mapping. The decrease in the thermal conductivity of the same cathode observed after each set of electrical test cycles is correlated with the volume changes and formation of low ionic and thermal conductivity lithium oxide and lithium oxychloride at the interface and along porous regions. The interface between the metal current collector and the cathode is also found to be responsible for the increase in thermal resistance. The results indicate that changes in the thermal conductivity of the electrodes provide a measure of the resistance to heat transfer and degradation of ionic transport in the cathode accompanying the charge-discharge cycles in the batteries.

Thin composite films consisting of polypyrrole and polyparaphenylene

International Nuclear Information System (INIS)

Golovtsov, I.; Bereznev, S.; Traksmaa, R.; Opik, A.

2007-01-01

This study demonstrates that the combined method for the formation of thin composite films, consisting of polypyrrole (PPy) as a film forming agent and polyparaphenylene (PPP) with controlled electrical properties and high stability, enables one to avoid the low processability of PPP and to extend the possibilities for the development of electronic devices. The high temperature (250-600 deg. C) doping method was used for PPP preparation. The crystallinity and grindability of PPP was found to be increasing with the thermochemical modification. Thin composite films were prepared onto the light transparent substrates using the simple electropolymerization technique. The properties of films were characterized by the optical transmittance and temperature-dependent conductivity measurements. The morphology and thickness of the prepared films were determined using the scanning electron microscopy. The composite films showed a better adhesion to an inorganic substrate. It was found to be connected mostly with the improved properties of the high temperature doped PPP. The current-voltage characteristics of indium tin oxide/film/Au hybrid organic-inorganic structures showed the influence of the doping conditions of PPP inclusions in the obtained films

Synthesis of diamond-like carbon via PECD using a streaming neutral gas injection hollow cathode

International Nuclear Information System (INIS)

Pacho, A.; Pares, E.; Ramos, H.; Mendenilla, A.; Malapit, G.

2009-01-01

A streaming neutral gas injection hollow cathode system was used to deposit diamond-like carbon films via plasma enhanced chemical vapor deposition on silicon and nickel-coated silicon substrates with acetylene and hydrogen as reactant gases. Samples were characterized using SEM and Raman spectroscopy. The work presented here aims to demonstrate the capability of the system to synthesize carbonaceous films and is starting point towards work on formation of carbon nanostructures. (author)

Cathodic electrodeposition of CuInSe sub 2 thin films

Energy Technology Data Exchange (ETDEWEB)

Guillen, C; Galiano, E; Herrero, J [Inst. de Energias Renovables (CIEMAT), Madrid (Spain)

1991-01-01

In order to study the preparation process of CuInSe{sub 2} thin films by a one-step electrodeposition method, thin films of the compound were prepared from aqueous citric acid (C{sub 6}H{sub 8}O{sub 7} . H{sub 2}O) plating baths onto titanium substrates. During electrodeposition, the bath composition and deposition potential were changed to obtain stoichiometric thin films. In general, close to stoichiometry, layers rich in selenium were observed, and this excess of selenium was removed after heat treatment. Best quality films were obtained after annealing at 400deg C during 15 min. X-ray diffraction showed the formation of CuInSe{sub 2} films, the chalcopyrite structure, at heating treatment temperatures higher than 350deg C. Optical measurements showed that the band gap of the deposited material was 0.99 eV. (orig.).

Cataphoretic assembly of cationic dyes and deposition of carbon nanotube and graphene films.

Science.gov (United States)

Su, Y; Zhitomirsky, I

2013-06-01

Cathodic electrophoretic deposition (EPD) method has been developed for the fabrication of thin films from aqueous solutions of crystal violet (CV) dyes. The films contained rod-like particles with a long axis oriented perpendicular to the substrate surface. The proposed deposition mechanism involved cataphoresis of cationic CV(+) species, base generation in the cathodic reactions, and charge neutralization at the electrode surface. The assembly of rod-like particles was governed by π-π interactions of polyaromatic CV molecules. The deposition kinetics was studied by quartz crystal microbalance. CV dyes allowed efficient dispersion of multiwalled carbon nanotubes (MWCNTs) and graphene in water at relatively low CV concentrations. The feasibility of cathodic EPD of MWCNT and graphene from aqueous suspensions, containing CV, has been demonstrated. The deposition yield was investigated at different CV concentrations and deposition voltages. The relatively high deposition yield of MWCNT and graphene indicated that CV is an efficient dispersing, charging, and film forming agent for EPD. Electron microscopy data showed that at low CV concentrations in MWCNT or graphene suspensions and low deposition voltages, the films contained mainly MWCNT or graphene. The increase in the CV concentration and/or deposition voltage resulted in enhanced co-deposition of CV. The EPD method developed in this investigation paves the way for the fabrication of advanced nanocomposites by cathodic electrodeposition. Copyright © 2013 Elsevier Inc. All rights reserved.

Comparative study of structural and electro-optical properties of ZnO:Ga films grown by steered cathodic arc plasma evaporation and sputtering on plastic and their application on polymer-based organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Liang, Chih-Hao, E-mail: dataman888@hotmail.com [R& D Division, Walsin Technology Corporation, Kaohsiung, Taiwan (China); Hsiao, Yu-Jen [National Nano Device Laboratories, National Applied Research Laboratories, Tainan, Taiwan (China); Hwang, Weng-Sing [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China)

2016-08-01

Ga-doped ZnO (GZO) films with various thicknesses (105–490 nm) were deposited on PET substrates at a low temperature of 90 °C by a steered cathodic arc plasma evaporation (steered CAPE), and a GZO film with a thickness of 400 nm was deposited at 90 °C by a magnetron sputtering (MS) for comparison. The comparative analysis of the microstructure, residual stress, surface morphology, electrical and optical properties, chemical states, and doping efficiency of the films produced by the steered CAPE and MS processes was performed, and the effect of thickness on the CAPE-grown GZO films was investigated in detail. The results showed that the GZO films grown by steered CAPE exhibited higher crystallinity and lower internal stress than those deposited by MS. The transmittance and electrical properties were also enhanced for the steered CAPE-grown films. The figure of merit (Φ = T{sup 10}/R{sub s}, where T is the transmittance and R{sub s} is the sheet resistance in Ω/□). was used to evaluate the performance of the electro-optical properties. The GZO films with a thickness of 400 nm deposited by CAPE had the highest Φ value, 1.94 × 10{sup −2} Ω{sup −1}, a corresponding average visible transmittance of 88.8% and resistivity of 6.29 × 10{sup −4} Ω·cm. In contrast, the Φ value of MS-deposited GZO film with a thickness of 400 nm is only 1.1 × 10{sup −3} Ω{sup −1}. This can be attributed to the increase in crystalline size, [0001] preferred orientation, decrease in stacking faults density and Ar contamination in steered CAPE-grown films, leading to increases in the Hall mobility and carrier density. In addition, the power conversion efficiency (PCE) of organic solar cells was significantly improved by using the CAPE-grown GZO electrode, and the PCE values were 1.2% and 1.7% for the devices with MS-grown and CAPE-grown GZO electrodes, respectively. - Highlights: • ZnO:Ga (GZO) films were grown on PET by steered cathodic arc plasma evaporation (CAPE

Mammographic microcalcifications: Detection with xerography, screen-film, and digitized film display

International Nuclear Information System (INIS)

Smathers, R.L.; Bush, E.; Drace, J.; Stevens, M.; Sommer, F.G.; Brown, B.W.; Karras, B.

1986-01-01

Pulverized bone specks and aluminum oxide specks were measured by hand into sizes ranging from 0.2 mm to 1.0 mm and then arranged in clusters. These clusters were superimposed on a human breast tissue phantom, and xeromammograms and screen-film mammograms of the clusters were made. The screen-film mammograms were digitized using a high-resolution laser scanner and then displayed on cathode ray tube (CRT) monitors. Six radiologists independently counted the microcalcifications on the xeromammograms, the screen-film mammograms, and the digitized film mammograms. The xeromammograms were examined with a magnifying glass; the screen-film images were examined with a magnifying glass and by hot light; and the digitized-film images were examined by electronic magnification and image processing. The bone speck size that corresponded to a mean 50% detectability level for each technique was as follows: xeromammography, 0.550 mm; digitized film, 0.573 mm; and screen-film, 0.661 mm. We postulate that electronic magnification and image processing with edge enhancement can improve the capability of screen-film mammography to enhance the detection of microcalcifications

Plasma source ion implantation of metal ions: Synchronization of cathodic-arc plasma production and target bias pulses

International Nuclear Information System (INIS)

Wood, B.P.; Reass, W.A.; Henins, I.

1995-01-01

An erbium cathodic-arc has been installed on a Plasma Source Ion Implantation (PSII) experiment to allow the implantation of erbium metal and the growth of adherent erbia (erbium oxide) films on a variety of substrates. Operation of the PSII pulser and the cathodic-arc are synchronized to achieve pure implantation, rather than the hybrid implantation/deposition being investigated in other laboratories. The relative phase of the 20 μs PSII and cathodic-arc pulses can to adjusted to tailor the energy distribution of implanted ions and suppress the initial high-current drain on the pulse modulator. The authors present experimental data on this effect and make a comparison to results from particle-in-cell simulations

Analysis of cathode geometry to minimize cathode erosion in direct current microplasma jet

Energy Technology Data Exchange (ETDEWEB)

Causa, Federica [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Universita degli studi di Messina, 98122 Messina (Italy); Ghezzi, Francesco; Caniello, Roberto; Grosso, Giovanni [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dellasega, David [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dipartimento di Energia, Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy)

2012-12-15

Microplasma jets are now widely used for deposition, etching, and materials processing. The present study focuses on the investigation of the influence of cathode geometry on deposition quality, for microplasma jet deposition systems in low vacuum. The interest here is understanding the influence of hydrogen on sputtering and/or evaporation of the electrodes. Samples obtained with two cathode geometries with tapered and rectangular cross-sections have been investigated experimentally by scanning electron microscopy and energy dispersion X-ray spectroscopy. Samples obtained with a tapered-geometry cathode present heavy contamination, demonstrating cathode erosion, while samples obtained with a rectangular-cross-section cathode are free from contamination. These experimental characteristics were explained by modelling results showing a larger radial component of the electric field at the cathode inner wall of the tapered cathode. As a result, ion acceleration is larger, explaining the observed cathode erosion in this case. Results from the present investigation also show that the ratio of radial to axial field components is larger for the rectangular geometry case, thus, qualitatively explaining the presence of micro-hollow cathode discharge over a wide range of currents observed in this case. In the light of the above findings, the rectangular cathode geometry is considered to be more effective to achieve cleaner deposition.

Improvement in the corrosion protection and bactericidal properties of AZ91D magnesium alloy coated with a microstructured polypyrrole film

Directory of Open Access Journals (Sweden)

A.D. Forero López

2018-03-01

Full Text Available In this work hollow rectangular microtubes of polypyrrole (PPy films were potentiostatically electrodeposited on magnesium alloy AZ91D in salicylate solution. The substrate was previously anodized under potentiostatic conditions in a molybdate solution in order to improve the adherence of polymer. Finally the duplex film was modified by the incorporation of silver species. The obtained coatings were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and X-ray photoelectron spectroscopies (XPS and the antimicrobial activity against the bacteria Escherichia coli was evaluated. The corrosion protection properties of the coatings were examined in Ringer solution by monitoring the open circuit potential, polarization techniques and electrochemical spectroscopy (EIS. The duplex coating presents an improved anticorrosive performance with respect to the PPy film. The best results concerning corrosion protection and antibacterial activity were obtained for the silver-modified composite coating. Keywords: Polypyrrole, Duplex coating, AZ91D alloy, Corrosion resistance, Antibacterial properties

Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

Science.gov (United States)

Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

2015-02-01

Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

Modification of Screen Printed Carbon Electrode (SPCE with Polypyrrole (Ppy-SiO2 for Phenol Determination

Directory of Open Access Journals (Sweden)

Ani Mulyasuryani

2018-01-01

Full Text Available Electrode modification on screen printed carbon electrode (SPCE with polypyrrole (Ppy-SiO2 was done by electropolymerization. Polypyrrole (Ppy-SiO2 was used for phenol determination. The analysis of this material was done by using Scanning Electron Microscopy (SEM, cyclic voltammetry method and differential pulse voltammetry. In a cyclic voltammetry analysis, we used potential range of -1 to 1 V with Ag/AgCl comparator electrode at scan rate of 100 mV/sec, while in differential pulse voltammetry method the potential range was 0 to 1 V toward Ag/AgCl, the scan rate of 50 mV/sec, the pulse rate is 0,2 V and the pulse width is 50 ms. From the analysis result with SEM, cyclic voltammetry and differential pulse voltammetry method, Polypyrrole (Ppy -SiO2 is the best material and can be used as phenol measurement.

Fabrication of conductive and high-dispersed Ppy@Ag/g-C{sub 3}N{sub 4} composite photocatalysts for removing various pollutants in water

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zhi; Tang, Xu [School of Chemistry and Chemical Engineering, Jiangsu University (China); Ma, Changchang [School of the Environment and Safety Engineering, Jiangsu University (China); Song, Minshan [School of Mathematics and Physics, Jiangsu University of Science and Technology (China); Gao, Nailing; Wang, Youshan; Huo, Pengwei [School of Chemistry and Chemical Engineering, Jiangsu University (China); Lu, Ziyang, E-mail: mrzhuzhi007@163.com [School of the Environment and Safety Engineering, Jiangsu University (China); Yan, Yongsheng, E-mail: gchxz206@126.com [School of Chemistry and Chemical Engineering, Jiangsu University (China)

2016-11-30

Highlights: • The high-dispersed Ag modified g-C{sub 3}N{sub 4} (Ag/g-C{sub 3}N{sub 4}) was successfully synthesized in situ deposited on the surface of g-C{sub 3}N{sub 4} during calcined melamine. • The as-prepared Ppy@Ag/g-C{sub 3}N{sub 4} could remove of various organic pollutants in water. • The enhanced photocatalytic activity of Ppy@Ag/g-C{sub 3}N{sub 4} comes from π conjugated electronic structures of Ppy and Ag species as the electron transfer mediator between Ppy and g-C{sub 3}N{sub 4}. • The Ppy@Ag/g-C{sub 3}N{sub 4} sample also showed a relatively good recycling stability. - Abstract: The ternary conductive Ppy@Ag/g-C{sub 3}N{sub 4} composite photocatalysts was successfully synthesized by polymerization process and surface polymerization technique. And the as-prepared Ppy@Ag/g-C{sub 3}N{sub 4} sample exhibited the higher photocatalytic activity for various pollutant (MO, DM, TC, CIP, GFLX and EH) remove than that of pure g-C{sub 3}N{sub 4} and Ag/g-C{sub 3}N{sub 4} under visible light irradiation. It mainly originated from the Ag nanoparticles anchored between g-C{sub 3}N{sub 4} and Ppy acted as electron transfer mediator that facilitated the charge carrier separation and then expending the lifetime of the carriers. Meanwhile, the obtained Ppy@Ag/g-C{sub 3}N{sub 4} sample also showed a relatively good recycling stability which was the crucial factor for photocatalyst practical application. This work provided a new facile strategy for improving photo-degradation activity of g-C{sub 3}N{sub 4} photocatalyst.

Evaluation of a New Biosensor Based on in Situ Synthesized PPy-Ag-PVP Nanohybrid for Selective Detection of Dopamine.

Science.gov (United States)

Vellaichamy, Balakumar; Periakaruppan, Prakash; Paulmony, Tharmaraj

2017-02-09

In the present work, in situ synthesis of polypyrrole-silver-polyvinylpyrrolidone (PPy-Ag-PVP) nanohybrid using AgNO 3 as an oxidant and polyvinylpyrrolidone (PVP) as a stabilizer and surfactant is demonstrated. The obtained ternary PPy-Ag-PVP nanohybrid was characterized by UV-vis, FT-IR, XRD, Raman, TGA, SEM, and HR-TEM analysis. Further the synthesized PPy-Ag-PVP has been investigated for its selective and sensitive sensing of dopamine (DA). The PPy-Ag-PVP modified glassy carbon electrode shows a reversible electrochemical behavior with superior response for DA. The limit of detection and limit of quantification are found to be 0.0126 and 0.042 μM (S/N = 3 and 10), respectively, with remarkable sensitivity (7.26 μA mM -1 cm -2 ). The practical application of the present modified electrode has been validated by determining the concentration of DA in human urine samples of different age group.

Depression cathode structure for cathode ray tubes having surface smoothness and method for producing same

International Nuclear Information System (INIS)

Rychlewski, T.V.

1984-01-01

Depression cathode structures for cathode ray tubes are produced by dispensing liquid cathode material into the depression of a metallic supporting substrate, removing excess cathode material by passing a doctor blade across the substrate surface and over the depression, and drying the cathode layer to a substantially immobile state. The cathode layer may optionally be further shaped prior to substantially complete drying thereof

Synthesis and characterization of novel PPy/Bi{sub 2}O{sub 2}CO{sub 3} composite with improved photocatalytic activity for degradation of Rhodamine-B

Energy Technology Data Exchange (ETDEWEB)

Wang, Qizhao, E-mail: wangqizhao@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou 730070 (China); Zheng, Longhui; Chen, Yutao; Fan, Jiafeng [College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou 730070 (China); Huang, Haohao, E-mail: scuthhh@hotmail.com [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Su, Bitao [College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou 730070 (China)

2015-07-15

Highlights: • A new photocatalyst PPy/Bi{sub 2}O{sub 2}CO{sub 3} was synthesized by a simple hydrothermal method. • The PPy/Bi{sub 2}O{sub 2}CO{sub 3} photocatalyst shows enhanced degradation activity of RhB under UV light irradiation. • A photocatalytic mechanism is proposed based on the synergistic effect of PPy and Bi{sub 2}O{sub 2}CO{sub 3}. - Abstract: Photocatalyst Bi{sub 2}O{sub 2}CO{sub 3} modified by polypyrrole (PPy) was synthesized via a facile hydrothermal method. As-prepared PPy/Bi{sub 2}O{sub 2}CO{sub 3} composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–vis diffuse reflectance spectroscopy (DRS). Presence of PPy did not affect the crystal structure, but exerted great influence on the photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3} and enhanced absorption band of pure Bi{sub 2}O{sub 2}CO{sub 3}. The photocatalytic activities of the PPy/Bi{sub 2}O{sub 2}CO{sub 3} samples were determined by photocatalytic degradation of Rhodamine-B (RhB) under ultra violet (UV) irradiation and 0.75 wt.% PPy/Bi{sub 2}O{sub 2}CO{sub 3} composite showed the highest photocatalytic activity. The enhanced photocatalytic performance could be attributed to the synergistic effect of PPy and Bi{sub 2}O{sub 2}CO{sub 3}. A possible photocatalytic mechanism of the PPy/Bi{sub 2}O{sub 2}CO{sub 3} photocatalysts was proposed in order to guide the further improvement of its photocatalytic performance.

Enzymatic effect of a bio-film on corrosion of stainless steels immersed in natural seawater

International Nuclear Information System (INIS)

L'Hostis, V.

2002-09-01

Immersion of stainless steels in natural seawater leads to an ennoblement of their free corrosion potential (Ecor) with time. This evolution is linked to colonization of surface by bacteria, forming a bio-film. Literature synthesis has showed common points between proposed mechanisms, like a modification of cathodic reactions, and importance of hydrogen peroxide, but also differences, as acidity inside bio-films, or chemical composition of the passive layer, or enzymes present inside bio-films. The aim of the study was to precise these hypothesis, and finally mechanisms which leads to increase of Ecor. Experiments with addition of enzymes (glucose oxidase) have been performed and have lead to reproduce the electrochemical behaviour of stainless steels in natural seawater, including the cathodic behaviour. Study of composition of passive film and its semi-conducting properties, analysed respectively by XPS and Mott-Schottky plots, has lead to precise roles of hydrogen peroxide and oxidases. Moreover, study of donor densities of passive film has pointed out the effect of gluconic acid for evolution of cathodic reaction. This enzymatic mechanism has been applied and verified on crevice corrosion, and has been extended to other metallic materials, and other enzymes. (author)

Direct current-induced electrogenerated chemiluminescence of hydrated and chelated Tb(III) at aluminum cathodes

International Nuclear Information System (INIS)

Hakansson, M.; Jiang, Q.; Spehar, A.-M.; Suomi, J.; Kotiranta, M.; Kulmala, S.

2005-01-01

Cathodic DC polarization of oxide-covered aluminum produces electrogenerated chemiluminescence from hydrated and chelated Tb(III) ions in aqueous electrolyte solutions. At the moment of cathodic voltage onset, a strong cathodic flash is observed, which is attributed to a tunnel emission of hot electrons into the aqueous electrolyte solution and the successive chemical reactions with the luminophores. However, within a few milliseconds the insulating oxide film is damaged and finally dissolved due to (i) indiffusion of protons or alkali metal ions into the thin oxide film, (ii) subsequent hydrogen evolution at the aluminum/oxide interface and (iii) alkalization of the electrode surface induced by hydrogen evolution reaction. When the alkalization of the electrode surface has proceeded sufficiently, chemiluminescence is generated with increasing intensity. Aluminum metal, short-lived Al(II), Al(I) or atomic hydrogen and its conjugated base form, hydrated electron, can act as highly reducing species in addition to the less energetic heterogeneously transferred electrons from the aluminum electrode. Tb(III) added as a hydrated ion in the solution probably luminesces in the form of Tb(OH) 3 or Tb(OH) 4 - by direct redox reactions of the central ion whereas multidentate aromatic ligand chelated Tb(III) probably luminesces by ligand sensitized chemiluminescence mechanism in which ligand is first excited by one-electron redox reactions, which is followed by intramolecular energy transfer to the central ion which finally emits light

Discovering functional interdependence relationship in PPI networks for protein complex identification.

Science.gov (United States)

Lam, Winnie W M; Chan, Keith C C

2012-04-01

Protein molecules interact with each other in protein complexes to perform many vital functions, and different computational techniques have been developed to identify protein complexes in protein-protein interaction (PPI) networks. These techniques are developed to search for subgraphs of high connectivity in PPI networks under the assumption that the proteins in a protein complex are highly interconnected. While these techniques have been shown to be quite effective, it is also possible that the matching rate between the protein complexes they discover and those that are previously determined experimentally be relatively low and the "false-alarm" rate can be relatively high. This is especially the case when the assumption of proteins in protein complexes being more highly interconnected be relatively invalid. To increase the matching rate and reduce the false-alarm rate, we have developed a technique that can work effectively without having to make this assumption. The name of the technique called protein complex identification by discovering functional interdependence (PCIFI) searches for protein complexes in PPI networks by taking into consideration both the functional interdependence relationship between protein molecules and the network topology of the network. The PCIFI works in several steps. The first step is to construct a multiple-function protein network graph by labeling each vertex with one or more of the molecular functions it performs. The second step is to filter out protein interactions between protein pairs that are not functionally interdependent of each other in the statistical sense. The third step is to make use of an information-theoretic measure to determine the strength of the functional interdependence between all remaining interacting protein pairs. Finally, the last step is to try to form protein complexes based on the measure of the strength of functional interdependence and the connectivity between proteins. For performance evaluation

Controlling In–Ga–Zn–O thin films transport properties through density changes

Energy Technology Data Exchange (ETDEWEB)

Kaczmarski, Jakub, E-mail: kaczmarski@ite.waw.pl [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Boll, Torben [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden); Borysiewicz, Michał A. [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Taube, Andrzej [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Institute of Microelectronics & Optoelectronics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); Thuvander, Mattias; Law, Jia Yan [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden); Kamińska, Eliana [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Stiller, Krystyna [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden)

2016-06-01

In the following study we investigate the effect of the magnetron cathode current (I{sub c}) during reactive sputtering of In–Ga–Zn–O (a-IGZO) on thin-films nanostructure and transport properties. All fabricated films are amorphous, according to X-ray diffraction measurements. However, High Resolution Transmission Electron Microscopy revealed the a-IGZO fabricated at I{sub C} = 70 mA to contain randomly-oriented nanocrystals dispersed in amorphous matrix, which disappear in films deposited at higher cathode current. These nanocrystals have the same composition as the amorphous matrix. One can observe that, while I{sub C} is increased from 70 to 150 mA, the carrier mobility improves from μ{sub Hall} = 6.9 cm{sup 2}/Vs to μ{sub Hall} = 9.1 cm{sup 2}/Vs. Additionally, the increase of I{sub C} caused a reduction of the depletion region trap states density of the Ru–Si–O/In–Ga–Zn–O Schottky barrier. This enhancement in transport properties is attributed to the greater overlapping of s-orbitals of the film-forming cations caused by increased density, evidenced by X-ray reflectivity, at a fixed chemical composition, regardless nanostructure of thin films. - Highlights: • Magnetron cathode current (I{sub C}) controls the transport properties of In–Ga–Zn–O (IGZO). • Low I{sub C} results in IGZO films with nanocrystalline inclusions in amorphous matrix. • High I{sub C} reduces the number of trap states in depletion region of Schottky contacts.

The mechanism of cathodic electrodeposition of epoxy coatings and the corrosion behaviour of the electrodeposited

Directory of Open Access Journals (Sweden)

VESNA B. MISKOVIC-STANKOVIC

2002-05-01

Full Text Available The model of organic film growth on a cathode during electrodeposition process proposes the current density-time and film thickness-time relationships and enables the evaluation of the rate contants for the electrochemical reaction of OH– ion evolution and for the chemical reaction of organic film deposition. The dependences of film thickness and rate constants on the applied voltage, bath temperature and resin concentration in the electrodeposition bath have also been obtained. The deposition parameters have a great effect on the cathodic electrodeposition process and on the protective properties of the obtained electrodeposited coatings. From the time dependences of the pore resistance, coating capacitance and relative permittivity, obtained from impedance measurements, the effect of applied voltage, bath temperature and resin concentration on the protective properties of electrodeposited coatings has been shown. Using electrochemical impedance spectroscopy, thermogravimetric analysis, gravimetric liquid sorption experiments, differential scanning calorimetry and optical miscroscopy, the corrosion stability of epoxy coatings was investigated. A mechanism for the penetration of electrolyte through an organic coating has been suggested and the shape and dimensions of the conducting macropores have been determined. It was shown that conduction through a coating depends only on the conduction through the macropores, although the quantity of electrolyte in the micropores of the polymer net is about one order of magnitude greater than that inside the conducting macropores.

Observation of radio frequency ring-shaped hollow cathode discharge plasma with MgO and Al electrodes for plasma processing

International Nuclear Information System (INIS)

Ohtsu, Yasunori; Matsumoto, Naoki

2014-01-01

Various high-density plasma sources have been proposed for plasma processing. Especially, the hollow cathode discharge is one of the powerful ones. In this work, radio-frequency (RF) driven ring-shaped hollow cathode discharges with high secondary-electron emission have been investigated, using an aluminum (Al) cathode, coated or not with magnesium oxide (MgO). The thickness of MgO thin film is approximately 200 nm. The RF discharge voltage for the coated cathode is almost the same as that for the uncoated one, in a wide range of Ar gas pressure, from 5.3 to 53.2 Pa. The results reveal that the plasma density has a peak at an Ar gas pressure of 10.6 Pa for both cathodes. The plasma density for the coated cathode is about 1.5–3 times higher than that for the uncoated one, at various gas pressures. To the contrary, the electron temperature for the coated cathode is lower than temperature obtained with the uncoated cathode, at various gas pressures. Radial profiles of electron saturation current, which is proportional to plasma flux, are also examined for a wide range of gas pressure. Radial profiles of electron temperature at various axial positions are almost uniform for both cathodes so that the diffusion process due to density gradient is dominant for plasma transport. The secondary electrons emitted from the coated cathode contribute to the improvement of the plasma flux radial profile obtained using the uncoated cathode

Surfactant-dependent macrophage response to polypyrrole-based coatings electrodeposited on Ti6Al7Nb alloy

Energy Technology Data Exchange (ETDEWEB)

Mindroiu, Mihaela [University Polytechnica of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061, Bucharest (Romania); Ion, Raluca [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095, Bucharest (Romania); Pirvu, Cristian [University Polytechnica of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061, Bucharest (Romania); Cimpean, Anisoara, E-mail: anisoara.cimpean@bio.unibuc.ro [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095, Bucharest (Romania)

2013-08-01

In this study, polypyrrole (PPy) films were successfully synthesized on Ti6Al7Nb alloy by potentiostatic polymerization in the presence of poly(sodium 4-styrenesulfonate) (NaPSS), t-octylphenoxy polyethoxyethanol (Triton X-100) and N-dodecyl-β-D-maltoside (DM) surfactants. Atomic force microscopy (AFM) analysis of the PPy/surfactant composite films revealed a granular structure characterized by a lower surface roughness than un-modified PPy films. The results demonstrated that addition of surfactants, namely Triton X-100 and DM, can improve electrochemical film stability and corrosion resistance. Further, Triton X-100 enhanced the adhesive strength of PPy films to the substrate. The surfactant type also showed a great influence on the surface wettability, the highest hydrophilic character being observed in the case of PPy/PSS film. Few studies have been devoted to the elucidation of inflammatory cell response to PPy-based materials. Therefore, RAW 264.7 macrophages were cultured on PPy-surfactant films to determine whether they elicit a differential cell behavior in terms of cell adhesion, proliferation, cellular morphology and cytokine secretion. Our results highlight the dependence of macrophage response on the surfactants used in the pyrrole polymerization process and suggest that the immune response to biomaterials coated with PPy films might be controlled by the choice of surfactant molecules. Highlights: • We electrodeposited polypyrrole films on Ti6Al7Nb alloy using three surfactants. • Differences in electrostability and wettability of polypyrrole films were found. • Triton X increased and NaPSS decreased the adhesion of polypyrrole films to Ti6Al7Nb. • Cytoskeletal architecture and macrophage activation were affected by surfactants. • The hydrophilic PPy/PSS coating elicited the lowest inflammatory response.

Surfactant-dependent macrophage response to polypyrrole-based coatings electrodeposited on Ti6Al7Nb alloy

International Nuclear Information System (INIS)

Mindroiu, Mihaela; Ion, Raluca; Pirvu, Cristian; Cimpean, Anisoara

2013-01-01

In this study, polypyrrole (PPy) films were successfully synthesized on Ti6Al7Nb alloy by potentiostatic polymerization in the presence of poly(sodium 4-styrenesulfonate) (NaPSS), t-octylphenoxy polyethoxyethanol (Triton X-100) and N-dodecyl-β-D-maltoside (DM) surfactants. Atomic force microscopy (AFM) analysis of the PPy/surfactant composite films revealed a granular structure characterized by a lower surface roughness than un-modified PPy films. The results demonstrated that addition of surfactants, namely Triton X-100 and DM, can improve electrochemical film stability and corrosion resistance. Further, Triton X-100 enhanced the adhesive strength of PPy films to the substrate. The surfactant type also showed a great influence on the surface wettability, the highest hydrophilic character being observed in the case of PPy/PSS film. Few studies have been devoted to the elucidation of inflammatory cell response to PPy-based materials. Therefore, RAW 264.7 macrophages were cultured on PPy-surfactant films to determine whether they elicit a differential cell behavior in terms of cell adhesion, proliferation, cellular morphology and cytokine secretion. Our results highlight the dependence of macrophage response on the surfactants used in the pyrrole polymerization process and suggest that the immune response to biomaterials coated with PPy films might be controlled by the choice of surfactant molecules. Highlights: • We electrodeposited polypyrrole films on Ti6Al7Nb alloy using three surfactants. • Differences in electrostability and wettability of polypyrrole films were found. • Triton X increased and NaPSS decreased the adhesion of polypyrrole films to Ti6Al7Nb. • Cytoskeletal architecture and macrophage activation were affected by surfactants. • The hydrophilic PPy/PSS coating elicited the lowest inflammatory response

Quantifying esophagogastric junction contractility with a novel HRM topographic metric, the EGJ-Contractile Integral: normative values and preliminary evaluation in PPI non-responders.

Science.gov (United States)

Nicodème, F; Pipa-Muniz, M; Khanna, K; Kahrilas, P J; Pandolfino, J E

2014-03-01

Despite its obvious pathophysiological relevance, the clinical utility of measures of esophagogastric junction (EGJ) contractility is unsubstantiated. High-resolution manometry (HRM) may improve upon this with its inherent ability to integrate the magnitude of contractility over time and length of the EGJ. This study aimed to develop a novel HRM metric summarizing EGJ contractility and test its ability distinguish among subgroups of proton pump inhibitor non-responders (PPI-NRs). 75 normal controls and 88 PPI-NRs were studied. All underwent HRM. PPI-NRs underwent pH-impedance monitoring on PPI therapy scored in terms of acid exposure, number of reflux events, and reflux-symptom correlation and grouped as meeting all criteria, some criteria, or no criteria of abnormality. Control HRM studies were used to establish normal values for candidate EGJ contractility metrics, which were then compared in their ability to differentiate among PPI-NR subgroups. The EGJ contractile integral (EGJ-CI), a metric integrating contractility across the EGJ for three respiratory cycles, best distinguished the All Criteria PPI-NR subgroup from controls and other PPI-NR subgroups. Normal values (median, [IQR]) for this measure were 39 mmHg-cm [25-55 mmHg-cm]. The correlation between the EGJ-CI and a previously proposed metric, the lower esophageal sphincter-pressure integral, that used a fixed 10 s time frame and an atmospheric as opposed to gastric pressure reference was weak. Among HRM metrics tested, the EGJ-CI was best in distinguishing PPI-NRs meeting all criteria of abnormality on pH-impedance testing. Future prospective studies are required to explore its utility in management of broader groups of gastroesophageal reflux disease patients. © 2013 John Wiley & Sons Ltd.

Light radiation through a transparent cathode plate with single-walled carbon nanotube field emitters

International Nuclear Information System (INIS)

Jang, E.S.; Goak, J.C.; Lee, H.S.; Lee, S.H.; Han, J.H.; Lee, C.S.; Sok, J.H.; Seo, Y.H.; Park, K.S.; Lee, N.S.

2010-01-01

In the conventional carbon nanotube backlight units (CNT-BLUs), light passes through the phosphor-coated anode glass plate, which thus faces closely the thin film transistor (TFT) backplate of a liquid crystal display panel. This configuration makes heat dissipation structurally difficult because light emission and heat generation occur simultaneously at the anode. We propose a novel configuration of a CNT-BLU where the cathode rather than the anode faces the TFT backplate by turning it upside down. In this design, light passes through the transparent cathode glass plate while heating occurs at the anode. We demonstrated a novel design of CNT-BLU by fabricating transparent single-walled CNT field emitters on the cathode and by coating a reflecting metal layer on the anode. This study hopefully provides a clue to solve the anode-heating problem which would be inevitably confronted for high-luminance and large-area CNT-BLUs.

Decorating MOF-Derived Nanoporous Co/C in Chain-Like Polypyrrole (PPy Aerogel: A Lightweight Material with Excellent Electromagnetic Absorption

Directory of Open Access Journals (Sweden)

Xiaodong Sun

2018-05-01

Full Text Available To clear away the harmful effects of the increment of electromagnetic pollution, high performance absorbers with appropriate impedance matching and strong attenuation capacity are strongly desired. In this study, a chain-like PPy aerogel decorated with MOF-derived nanoporous Co/C (Co/C@PPy has been successfully prepared by a self-assembled polymerization method. With a filler loading ratio of 10 wt %, the composite of Co/C@PPy could achieve a promising electromagnetic absorption performance both in intensity and bandwidth. An optimal reflection loss value of −44.76 dB is achieved, and the effective bandwidth (reflection loss lower than −10 dB is as large as 6.56 GHz. Furthermore, a composite only loaded with 5 wt % Co/C@PPy also achieves an effective bandwidth of 5.20 GHz, which is even better than numerous reported electromagnetic absorption (EA materials. The result reveals that the as-fabricated Co/C@PPy—with high absorption intensity, broad bandwidth, and light weight properties—can be utilized as a competitive absorber.

Cathodic electrodeposition of ceramic and organoceramic materials. Fundamental aspects.

Science.gov (United States)

Zhitomirsky, I

2002-03-29

Electrodeposition of ceramic materials can be performed by electrophoretic (EPD) or electrolytic (ELD) deposition. Electrophoretic deposition is achieved via motion of charged particles towards an electrode under an applied electric field. Electrolytic deposition produces colloidal particles in cathodic reactions for subsequent deposition. Various electrochemical strategies and deposition mechanisms have been developed for electrodeposition of ceramic and organoceramic films, and are discussed in the present article. Electrode-position of ceramic and organoceramic materials includes mass transport, accumulation of particles near the electrode and their coagulation to form a cathodic deposit. Various types of interparticle forces that govern colloidal stability in the absence and presence of processing additives are discussed. Novel theoretical contributions towards an interpretation of particle coagulation near the electrode surface are reviewed. Background information is given on the methods of particle charging, stabilization of colloids in aqueous and non-aqueous media, electrophoretic mobility of ceramic particles and polyelectrolytes, and electrode reactions. This review also covers recent developments in the electrodeposition of ceramic and organoceramic materials.

Corrosion of conductive polypyrrole: Effects of environmental factors, electrochemical stimulation, and doping anions

International Nuclear Information System (INIS)

Qi Kai; Qiu Yubing; Chen Zhenyu; Guo Xingpeng

2012-01-01

Highlights: ► Corrosive galvanic cells form on PPy film with the electrochemical reduction of O 2. ► Suitable electrochemical stimulation can inhibit the PPy’s corrosion. ► PPy film doped with larger sized anions has better corrosion resistance performance. - Abstract: The effects of environmental factors, electrochemical stimulation, and doping anions on the corrosion behaviour of conductive polypyrrole (PPy) films in alkaline aqueous media were studied with cyclic voltammetry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. High concentrations of electrolyte, low dissolved oxygen and low temperatures enhance the stability of PPy. Polarising PPy at a negative potential inhibits its corrosion obviously. PPy doped with large counter anions shows better corrosion resistance than PPy doped with small counter ions. The possible mechanism involved in PPy corrosion process is discussed.

High Operating Voltage Supercapacitor Using PPy/AC Composite Electrode Based on Simple Dipping Method

Directory of Open Access Journals (Sweden)

Kyoungho Kim

2015-01-01

Full Text Available As various wearable devices are emerging, self-generated power sources, such as piezoelectric generators, triboelectric generators, and thermoelectric generators, are of interest. To adapt self-generated power sources for application devices, a supercapacitor is necessary because of the short generation times (1–10 ms and low generated power (1–100 μW of self-generated power sources. However, to date, supercapacitors are too large to be adapted for wearable devices. There have been many efforts to reduce the size of supercapacitors by using polypyrrole (PPy for high energy supercapacitor electrodes. However, these supercapacitors have several disadvantages, such as a low operating voltage due to the use of an aqueous electrolyte, and complex manufacturing methods, such as the hydrogel and aerosol methods. In particular, the low operating voltage (~1.0 V is a significant issue because most electronic components operate above 3.0 V. In this study, we successfully demonstrated the high operating voltage (3.0 V of a supercapacitor using a PPy/activated carbon (AC composite electrode based on the chemical polymerization of the PPy by simple dipping. In addition, a twofold enhancement of its energy density was achieved compared with conventional supercapacitors using AC electrodes.

Capacitive properties of polypyrrole/activated carbon composite

Directory of Open Access Journals (Sweden)

Porjazoska-Kujundziski Aleksandra

2014-01-01

Full Text Available Electrochemical synthesis of polypyrrole (PPy and polypyrrole / activated carbon (PPy / AC - composite films, with a thickness between 0.5 and 15 μm were performed in a three electrode cell containing 0.1 mol dm-3 Py, 0.5 mol dm-3 NaClO4 dissolved in ACN, and dispersed particles of AC (30 g dm-3. Electrochemical characterization of PPy and PPy / AC composites was performed using cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS techniques. The linear dependences of the capacitance (qC, redox capacitance (qred, and limiting capacitance (CL of PPy and PPy / AC - composite films on their thickness (L, obtained by electrochemical and impedance analysis, indicate a nearly homogeneous distribution of the incorporated AC particles in the composite films (correlation coefficient between 0.991 and 0.998. The significant enhancement of qC, qred, and CL, was observed for composite films (for ∼40 ± 5% in respect to that of the “pure” PPy. The decreased values of a volume resistivity in the reduced state of the composite film, ρ = 1.3 ⋅ 106 Ω cm (for L = 7.5 μm, for two orders of magnitude, compared to that of PPy - film with the same thickness, ρ ∼ 108 Ω cm, was also noticed.

Dielectric and AC Conductivity Studies in PPy-Ag Nanocomposites

OpenAIRE

Praveenkumar, K.; Sankarappa, T.; Ashwajeet, J. S.; Ramanna, R.

2015-01-01

Polypyrrole and silver nanoparticles have been synthesized at 277 K by chemical route. Nanoparticles of polypyrrole-silver (PPy-Ag) composites were prepared by mixing polypyrrole and silver nanoparticles in different weight percentages. Dielectric properties as a function of temperature in the range from 300 K to 550 K and frequency in the range from 50 Hz to 1 MHz have been measured. Dielectric constant decreased with increase in frequency and temperature. Dielectric loss decreased with incr...

Effect of the electrolyte cations and anions on the photocurrent of dodecylsulphate doped polypyrrole films

Energy Technology Data Exchange (ETDEWEB)

Martini, Milena; De Paoli, Marco-A. [Laboratorio de Poliimeros Condutores, Instituto de Quimica-UNICAMP, Universidade de Campinas, Cx Postal 6154, 13081-970 , SP Campinas (Brazil)

2002-07-01

Photoelectrochemical and UV-Vis spectroelectrochemical measurements were performed in a three-electrode cell containing dodecylsulphate-doped polypyrrole films as active layers in contact with different aqueous electrolytes. The effect of both cations and anions of the electrolyte on the photocurrent generation and on the absorption spectra of the system was studied. Dynamic photocurrent and absorption spectra measurements performed during the redox cycles of the films show that both cation and anion insertion and deinsertion occurs during the cycles. These results are in agreement with the previously reported redox mechanism proposed for amphiphilic anion doped polypyrrole. Reduced films show cathodic photocurrent at -0.4>E>-0.8V vs. Ag|AgCl. Photocurrent voltammograms are reproducible after the conditioning of the films and the higher cathodic currents were observed in films with thickness of =0.05-0.5{mu}m.

Nanostructured tungsten trioxide thin films synthesized for photoelectrocatalytic water oxidation: a review.

Science.gov (United States)

Zhu, Tao; Chong, Meng Nan; Chan, Eng Seng

2014-11-01

The recent developments of nanostructured WO3 thin films synthesized through the electrochemical route of electrochemical anodization and cathodic electrodeposition for the application in photoelectrochemical (PEC) water splitting are reviewed. The key fundamental reaction mechanisms of electrochemical anodization and cathodic electrodeposition methods for synthesizing nanostructured WO3 thin films are explained. In addition, the effects of metal oxide precursors, electrode substrates, applied potentials and current densities, and annealing temperatures on size, composition, and thickness of the electrochemically synthesized nanostructured WO3 thin films are elucidated in detail. Finally, a summary is given for the general evaluation practices used to calculate the energy conversion efficiency of nanostructured WO3 thin films and a recommendation is provided to standardize the presentation of research results in the field to allow for easy comparison of reported PEC efficiencies in the near future. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

True-color 640 ppi OLED arrays patterned by CA i-line photolithography

NARCIS (Netherlands)

Malinowski, P.E.; Ke, T.; Nakamura, A.; Chang, T.-Y.; Gokhale, P.; Steudel, S.; Janssen, D.; Kamochi, Y.; Koyama, I.; Iwai,Y.; Heremans, P.

2015-01-01

In this paper, side-by-side patterning of red, green and blue OLEDs is demonstrated. To achieve 640 ppi arrays with 20 µm subpixel pitch, chemically amplified, i-line photoresist system with submicron resolution was used. These results show feasibility of obtaining full-color displays with

High rate reactive sputtering in an opposed cathode closed-field unbalanced magnetron sputtering system

Science.gov (United States)

Sproul, William D.; Rudnik, Paul J.; Graham, Michael E.; Rohde, Suzanne L.

1990-01-01

Attention is given to an opposed cathode sputtering system constructed with the ability to coat parts with a size up to 15 cm in diameter and 30 cm in length. Initial trials with this system revealed very low substrate bias currents. When the AlNiCo magnets in the two opposed cathodes were arranged in a mirrored configuration, the plasma density at the substrate was low, and the substrate bias current density was less than 1 mA/sq cm. If the magnets were arranged in a closed-field configuration where the field lines from one set of magnets were coupled with the other set, the substrate bias current density was as high as 5.7 mA/sq cm when NdFeB magnets were used. In the closed-field configuration, the substrate bias current density was related to the magnetic field strength between the two cathodes and to the sputtering pressure. Hard well-adhered TiN coatings were reactively sputtered in the opposed cathode system in the closed-field configuration, but the mirrored configuration produced films with poor adhesion because of etching problems and low plasma density at the substrate.

Cathode materials review

Science.gov (United States)

Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

2014-06-01

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

Cathode materials review

International Nuclear Information System (INIS)

Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

2014-01-01

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO 2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research

Cathode materials review

Energy Technology Data Exchange (ETDEWEB)

Daniel, Claus, E-mail: danielc@ornl.gov; Mohanty, Debasish, E-mail: danielc@ornl.gov; Li, Jianlin, E-mail: danielc@ornl.gov; Wood, David L., E-mail: danielc@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS6472 Oak Ridge, TN 37831-6472 (United States)

2014-06-16

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO{sub 2} cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

Luminescent sensitization and blue shift emission of Ir(ppy){sub 2}(VPHD) by copolymerization with MMA

Energy Technology Data Exchange (ETDEWEB)

An Baoli, E-mail: blan@staff.shu.edu.cn [Department of Chemistry, College of Science, Shanghai University, Shanghai 200444 (China); Dai Fanzeng; Zhang Yanling; Song Jian; Huang, Xiao-Di [Department of Chemistry, College of Science, Shanghai University, Shanghai 200444 (China); Xu, Jia-Qiang, E-mail: xujiaqiang@shu.edu.cn [Department of Chemistry, College of Science, Shanghai University, Shanghai 200444 (China); State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

2011-08-15

Ir(ppy){sub 2}(VPHD) (ppy=2-phenyl pyridine, VPHD=6-(4-vinylphenyl)-2,4-hexanedione) was copolymerized with methyl methacrylate (MMA). The copolymer had high quantum yield of 52.3{+-}0.5% in dilute ethyl acetate solution, and the yield increased around 45% than that of the iridium monomer. The maximum emission peaks for the copolymers shifted from 515 to 489 nm while the iridium complex content was less than 0.005 mol% in the feed. The blue emission at 489 nm and the green emission at 520 nm were analyzed by Lorenz function. They are attributed to {sup 1}MLCT and {sup 3}MLCT emissions, respectively. - Highlights: > PMMA-Ir(ppy){sub 2}(VPHD) as luminescent material with high yield of 53%. > The blue color emission at 489 nm from {sup 1}MLCT in conformity with Lorenz function. > The quantum yield for the copolymer increases 45% than that of the iridium monomer. > The {sup 3}MLCT Ex. intensity versus the monomer concentration is in conformity with Boltzmann function.

Thin film plasma coatings from dielectric free-flowing materials

International Nuclear Information System (INIS)

Timofeeva, L.A.; Katrich, S.A.; Solntsev, L.A.

1994-01-01

Fabrication of thin film plasma coatings from insulating free-flowing materials is considered. Molybdenum-tart ammonium coating of 3...5 μ thickness deposited on glassy carbon, aluminium, silicon, nickel, cast iron and steel substrates in 'Bulat-ZT' machine using insulating free-flowing materials cathod was found to form due to adsorption, absorption and dissuasion processes. The use of insulating free-flowing materials coatings allow to exclude pure metals cathods in plasma-plating process

Nanostructured sulfur cathodes

KAUST Repository

Yang, Yuan

2013-01-01

Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

Adhesion of rhodium films on metallic substrates

International Nuclear Information System (INIS)

Marot, L.; Covarel, G.; Tuilier, M.-H.; Steiner, R.; Oelhafen, P.

2008-01-01

Rhodium coated metallic films were prepared by magnetron sputtering on metallic substrates. All films were elaborated in same conditions on copper, molybdenum and stainless steel. Adhesion strength tests were carried out by scratch test. The results reveal that the adhesion strength between the film and the substrate is influenced by the hardness of the substrate. Increase of deposition temperature improves the adhesion of the coating. In addition, pre-treatment of substrates by a filtered cathodic vacuum arc and the layer thickness have has some effects on the final adhesion strength

Adhesion of rhodium films on metallic substrates

Energy Technology Data Exchange (ETDEWEB)

Marot, L. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)], E-mail: laurent.marot@unibas.ch; Covarel, G.; Tuilier, M.-H. [Laboratoire Mecanique, Materiaux et Procedes de Fabrication, Pole STIC-SPI-Math 61 rue Albert Camus, Universite de Haute-Alsace, F-68093 - Mulhouse Cedex (France); Steiner, R.; Oelhafen, P. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2008-09-01

Rhodium coated metallic films were prepared by magnetron sputtering on metallic substrates. All films were elaborated in same conditions on copper, molybdenum and stainless steel. Adhesion strength tests were carried out by scratch test. The results reveal that the adhesion strength between the film and the substrate is influenced by the hardness of the substrate. Increase of deposition temperature improves the adhesion of the coating. In addition, pre-treatment of substrates by a filtered cathodic vacuum arc and the layer thickness have has some effects on the final adhesion strength.

Achieving high mobility ZnO : Al at very high growth rates by dc filtered cathodic arc deposition

International Nuclear Information System (INIS)

Mendelsberg, R J; Lim, S H N; Wallig, J; Anders, A; Zhu, Y K; Milliron, D J

2011-01-01

Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500-1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min -1 while maintaining resistivity below 5 x 10 -4 Ω cm with electron mobility as high as 60 cm 2 V -1 s -1 . (fast track communication)

Choice vs. voice? PPI policies and the re-positioning of the state in England and Wales.

Science.gov (United States)

Hughes, David; Mullen, Caroline; Vincent-Jones, Peter

2009-09-01

CONTEXT AND THESIS: Changing patient and public involvement (PPI) policies in England and Wales are analysed against the background of wider National Health Service (NHS) reforms and regulatory frameworks. We argue that the growing divergence of health policies is accompanied by a re-positioning of the state vis-à-vis PPI, characterized by different mixes of centralized and decentralized regulatory instruments. Analysis of legislation and official documents, and interviews with policy makers. In England, continued hierarchical control is combined with the delegation of responsibilities for the oversight and organization of PPI to external institutions such as the Care Quality Commission and local involvement networks, in support of the government's policy agenda of increasing marketization. In Wales, which has rejected market reforms and economic regulation, decentralization is occurring through the use of mixed regulatory approaches and networks suited to the small-country governance model, and seeks to benefit from the close proximity of central and local actors by creating new forms of engagement while maintaining central steering of service planning. Whereas English PPI policies have emerged in tandem with a pluralistic supply-side market and combine new institutional arrangements for patient 'choice' with other forms of involvement, the Welsh policies focus on 'voice' within a largely publicly-delivered service. While the English reforms draw on theories of economic regulation and the experience of independent regulation in the utilities sector, the Welsh model of local service integration has been more influenced by reforms in local government. Such transfers of governance instruments from other public service sectors to the NHS may be problematic.

Elemental redistribution in coloured films on SUS304 stainless steel produced by current pulse method

International Nuclear Information System (INIS)

Lin, C.J.; Duh, J.G.

1996-01-01

Coloured films are deposited on an SUS304 substrate by the square wave current pulse method in a 2.5 M CrO 3 + 5 M H 2 SO 4 solution at 75 C. The absolute ratio of anodic to cathodic charge density and the corresponding final value of cathodic potential provide an easy and appropriate approach to the control of colour in the current pulse colouring method. This is proved in this study for a frequency region lower than 1 Hz. The corresponding cathodic potential increases with increasing dwell time in the negative applied current region and is related to the colour tone of the deposited film. The total time required to obtain the same thickness of coloured film is shorter at lower frequency than at higher frequency, which takes more time to charge the double layer. The thickness of the coloured films is determined by both Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) depth profiling and is of submicron order. The film thickness is proportional to the introduced total charge per unit area in the current pulse colouring process. CrO + and FeO + ions are observed in the coloured films and their concentrations increase as the colouring time is increased. The Fe concentration in the coloured films is lower than that in the substrate and decreases with the colouring time. It is the iron species that first becomes involved in the anodic reaction and the spinel oxide structure of iron and chromium is present in the coloured films. (orig.)

Delocalization of π electrons and trapping action of ZnO nanoparticles in PPY matrix for hybrid solar cell application

Science.gov (United States)

Singh, Rajinder; Choudhary, Ram Bilash; Kandulna, Rohit

2018-03-01

Polypyrrole (PPY)-Zinc Oxide (ZnO) nanocomposites with varying concentration of ZnO (1:1-1:4) were prepared via in-situ polymerization technique by using pyrrole monomer in the presence of ammonium persulphate (APS) as oxidant. Globular morphology of PPY and sheet like structure of ZnO was examined using FESEM and EDAX. FTIR showed the presence of vibration modes in fingerprint region (1500 cm-1-500 cm-1) for metal oxides confirming the presence and interaction of ZnO with the polymer matrix in nanocomposites. Amorphous nature of PPY and hexagonal wurtzite structure of ZnO was confirmed using XRD with average crystallite size within 20 nm-30 nm. PANI-ZnO (1:1) exhibited blue shift in comparison to PPY (neat) and optimized optical band gap ∼ 1.81 eV. The effect of carrier concentration was investigated using electrochemical analyzer and maximum current was recorded for PANI-ZnO (1:1). The highest conductance was calculated for PANI-ZnO (1:1) ∼ 7.3242 × 10-3 S using current -voltage characteristics. Thermal stability was found to be increasing with the increase in ZnO concentration PANI-ZnO nanocomposite.

Arcjet cathode phenomena

Science.gov (United States)

Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

1989-01-01

Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

Kinetics of oxygen reduction in perovskite cathodes for solid oxide fuel cells: A combined modeling and experimental approach

Science.gov (United States)

Miara, Lincoln James

unknown rate constants (kad, k des, k1, k1¯ ), and parameters (Ds, Q°, n) arising from the governing equations are estimated from a combination of experiments, mathematical analysis, and numerical data analysis. In the second system, dense patterned films of cathode with composition: La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF-6428) were fabricated on Ga-doped CeO2 coated YSZ substrates. These samples were analyzed by EIS over a temperature and pO 2 range of 600--800 °C and 10-3--1.00 atm, respectively. To understand the EIS results, a 2-dimensional model was developed which accounted for surface oxygen exchange, and both surface and bulk transport of oxygen to the electrolyte interface. The results were obtained by numerically solving a stationary partial differential equation describing the oxygen vacancy distribution in the cathode. From these results, the model impedance was derived and then fitted to the experimental EIS results. From the fitting results the contributions to the impedance from each of the processes were estimated. Also, the surface exchange rate was estimated over the experimental operating conditions. Finally, the results suggest that the surface diffusion occurred by an interstitial type mechanism in this material. The cathode surface is intimately involved in most of the oxygen reduction processes; however, the surface structure and chemistry is typically treated as an extension of the bulk without consideration of the actual surface properties. Recent evidence suggests that significant changes occur to the surface during operation which in turn leads to changes in electrochemical performance. To investigate these phenomena, well-oriented thin films (250 nm in thickness) of Sr-doped lanthanum manginite (LSM) films were grown on single crystals of YSZ (111). Films which were cathodically biased with a -1 V applied dc potential were compared to control samples. The cathodic bias results in both an enhancement in electrochemical performance and a change in

Silver incorporated polypyrrole/polyacrylic acid electrode for electrochemical supercapacitor

Science.gov (United States)

Patil, Dipali S.; Pawar, Sachin A.; Kamble, Archana S.; Patil, Pramod S.

2013-06-01

In the present work, we study Ag doping effect on the specific capacitance of Polypyrrole/Polyacrylic Acid (PPy/PAA). Ag incorporated films were prepared by simple chemical route. Fourier transform-infrared and Fourier transform-Raman techniques were used for the phase identification. Surface morphology of the films was examined by Field Emission scanning electron microscopy and revealed granular structure for PPY, attached granules for PPy/PAA and granules with bright spots of Ag particles for the PPy/PAA/Ag films. The supercapacitive behavior of the electrodes was tested in three electrode system with 0.1 M H2SO4 electrolyte by using cyclic voltammetry. The highest specific capacitance value 226 Fg-1 was observed for the PPy/PAA/Ag film.

Nanodiamond embedded ta-C composite film by pulsed filtered vacuum arc deposition from a single target

Science.gov (United States)

Iyer, Ajai; Etula, Jarkko; Ge, Yanling; Liu, Xuwen; Koskinen, Jari

2016-11-01

Detonation Nanodiamonds (DNDs) are known to have sp3 core, sp2 shell, small size (few nm) and are gaining importance as multi-functional nanoparticles. Diverse methods have been used to form composites, containing detonation nanodiamonds (DNDs) embedded in conductive and dielectric matrices for various applications. Here we show a method, wherein DND-ta-C composite film, consisting of DNDs embedded in ta-C matrix have been co-deposited from the same cathode by pulsed filtered cathodic vacuum arc method. Transmission Electron Microscope analysis of these films revel the presence of DNDs embedded in the matrix of amorphous carbon. Raman spectroscopy indicates that the presence of DNDs does not adversely affect the sp3 content of DND-ta-C composite film compared to ta-C film of same thickness. Nanoindentation and nanowear tests indicate that DND-ta-C composite films possess improved mechanical properties in comparison to ta-C films of similar thickness.

Scanning electrochemical microscopy of graphene/polymer hybrid thin films as supercapacitors: Physical-chemical interfacial processes

Directory of Open Access Journals (Sweden)

Sanju Gupta

2015-10-01

Full Text Available Hybrid electrode comprising an electric double-layer capacitor of graphene nanosheets and a pseudocapacitor of the electrically conducting polymers namely, polyaniline; PAni and polypyrrole; PPy are constructed that exhibited synergistic effect with excellent electrochemical performance as thin film supercapacitors for alternative energy. The hybrid supercapacitors were prepared by layer-by-layer (LbL assembly based on controlled electrochemical polymerization followed by reduction of graphene oxide electrochemically producing ErGO, for establishing intimate electronic contact through nanoscale architecture and chemical stability, producing a single bilayer of (PAni/ErGO1, (PPy/ErGO1, (PAni/GO1 and (PPy/GO1. The rationale design is to create thin films that possess interconnected graphene nanosheets (GNS with polymer nanostructures forming well-defined tailored interfaces allowing sufficient surface adsorption and faster ion transport due to short diffusion distances. We investigated their electrochemical properties and performance in terms of gravimetric specific capacitance, Cs, from cyclic voltammograms. The LbL-assembled bilayer films exhibited an excellent Cs of ≥350 F g−1 as compared with constituents (∼70 F g−1 at discharge current density of 0.3 A g−1 that outperformed many other hybrid supercapacitors. To gain deeper insights into the physical-chemical interfacial processes occurring at the electrode/electrolyte interface that govern their operation, we have used scanning electrochemical microscopy (SECM technique in feedback and probe approach modes. We present our findings from viewpoint of reinforcing the role played by heterogeneous electrode surface composed of nanoscale graphene sheets (conducting and conducting polymers (semiconducting backbone with ordered polymer chains via higher/lower probe current distribution maps. Also targeted is SECM imaging that allowed to determine electrochemical (reactivity of surface ion

Scanning electrochemical microscopy of graphene/polymer hybrid thin films as supercapacitors: Physical-chemical interfacial processes

Energy Technology Data Exchange (ETDEWEB)

Gupta, Sanju, E-mail: sanju.gupta@wku.edu; Price, Carson [Department of Physics and Astronomy, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101-3576 (United States)

2015-10-15

Hybrid electrode comprising an electric double-layer capacitor of graphene nanosheets and a pseudocapacitor of the electrically conducting polymers namely, polyaniline; PAni and polypyrrole; PPy are constructed that exhibited synergistic effect with excellent electrochemical performance as thin film supercapacitors for alternative energy. The hybrid supercapacitors were prepared by layer-by-layer (LbL) assembly based on controlled electrochemical polymerization followed by reduction of graphene oxide electrochemically producing ErGO, for establishing intimate electronic contact through nanoscale architecture and chemical stability, producing a single bilayer of (PAni/ErGO){sub 1}, (PPy/ErGO){sub 1}, (PAni/GO){sub 1} and (PPy/GO){sub 1}. The rationale design is to create thin films that possess interconnected graphene nanosheets (GNS) with polymer nanostructures forming well-defined tailored interfaces allowing sufficient surface adsorption and faster ion transport due to short diffusion distances. We investigated their electrochemical properties and performance in terms of gravimetric specific capacitance, C{sub s}, from cyclic voltammograms. The LbL-assembled bilayer films exhibited an excellent C{sub s} of ≥350 F g{sup −1} as compared with constituents (∼70 F g{sup −1}) at discharge current density of 0.3 A g{sup −1} that outperformed many other hybrid supercapacitors. To gain deeper insights into the physical-chemical interfacial processes occurring at the electrode/electrolyte interface that govern their operation, we have used scanning electrochemical microscopy (SECM) technique in feedback and probe approach modes. We present our findings from viewpoint of reinforcing the role played by heterogeneous electrode surface composed of nanoscale graphene sheets (conducting) and conducting polymers (semiconducting) backbone with ordered polymer chains via higher/lower probe current distribution maps. Also targeted is SECM imaging that allowed to determine

Scanning electrochemical microscopy of graphene/polymer hybrid thin films as supercapacitors: Physical-chemical interfacial processes

Science.gov (United States)

Gupta, Sanju; Price, Carson

2015-10-01

Hybrid electrode comprising an electric double-layer capacitor of graphene nanosheets and a pseudocapacitor of the electrically conducting polymers namely, polyaniline; PAni and polypyrrole; PPy are constructed that exhibited synergistic effect with excellent electrochemical performance as thin film supercapacitors for alternative energy. The hybrid supercapacitors were prepared by layer-by-layer (LbL) assembly based on controlled electrochemical polymerization followed by reduction of graphene oxide electrochemically producing ErGO, for establishing intimate electronic contact through nanoscale architecture and chemical stability, producing a single bilayer of (PAni/ErGO)1, (PPy/ErGO)1, (PAni/GO)1 and (PPy/GO)1. The rationale design is to create thin films that possess interconnected graphene nanosheets (GNS) with polymer nanostructures forming well-defined tailored interfaces allowing sufficient surface adsorption and faster ion transport due to short diffusion distances. We investigated their electrochemical properties and performance in terms of gravimetric specific capacitance, Cs, from cyclic voltammograms. The LbL-assembled bilayer films exhibited an excellent Cs of ≥350 F g-1 as compared with constituents (˜70 F g-1) at discharge current density of 0.3 A g-1 that outperformed many other hybrid supercapacitors. To gain deeper insights into the physical-chemical interfacial processes occurring at the electrode/electrolyte interface that govern their operation, we have used scanning electrochemical microscopy (SECM) technique in feedback and probe approach modes. We present our findings from viewpoint of reinforcing the role played by heterogeneous electrode surface composed of nanoscale graphene sheets (conducting) and conducting polymers (semiconducting) backbone with ordered polymer chains via higher/lower probe current distribution maps. Also targeted is SECM imaging that allowed to determine electrochemical (re)activity of surface ion adsorption sites

Synthesis and characterization of LDH/Ppi composite and its application as adsorbent of 2,4-dichlorophenoxyacetic (herbicide); Sintese e caracterizacao do composito HDL/Ppi e sua aplicacao como adsorvente do 2,4-diclorofenoxiacetico (herbicida)

Energy Technology Data Exchange (ETDEWEB)

Pacheco, I.S.; Oliveira, R.S.; Girotto, L.G.; Freitas, L.L. de; Amaral, F.A. do; Canobre, S.C., E-mail: ingrid_1194@hotmail.com [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Quimica

2016-07-01

This work had as main objective the synthesis and characterization of LDH [Co-Al-Cl] method by hydrolysis of urea and then its synthesized polypyrrole coating by chemically targeting the application as adsorbent dichlorophenoxyacetic acid (2,4-D). The x-ray diffractogram of well defined showed diffraction peaks corresponding to the planes 003, 006, 009 and 110 which allow them to rhombohedral indexes and lamellar structure. The composite LDH / Ppi had a percentage of 49% herbicide retention in aqueous solution. From the investigated adsorption isotherm models that more fit the experimental data was the Freundlich, so it could be inferred that the interaction between the LDH / Ppi and the herbicide was physical, ie an rapid, reversible adsorption and does not specify. (author)

44-1: Invited Paper: Photolithography as Enabler of AMOLED Displays Beyond 1000 ppi

NARCIS (Netherlands)

Malinowski, P.E.; Ke, T.; Nakamura, A.; Vicca, P.; Kronemeijer, A.J.; Ameys, M.; Steen, J.L. van der; Steudel, S.; Kamochi, Y.; Iwai, Y.; Gelinck, G.; Heremans, P.

2017-01-01

This paper describes the potential of hi-res display fabrication using OLED photolithography. We demonstrate 1250 ppi multicolor arrays, pixel scaling down to 3 μm pitch, integration in active displays, and improving lifetime after patterning (200 hours T75, smOLEDs). Photolithography can enable

Cell adhesion to cathodic arc plasma deposited CrAlSiN thin films

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Kyu, E-mail: skim@ulsan.ac.kr [School of Materials Science and Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Pham, Vuong-Hung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Kim, Chong-Hyun [Department of Food Science, Cornell University, Ithaca, NY 14853 (United States)

2012-07-01

Osteoblast cell response (cell adhesion, actin cytoskeleton and focal contact adhesion as well as cell proliferation) to CrN, CrAlSiN and Ti thin films was evaluated in vitro. Cell adhesion and actin stress fibers organization depended on the film composition significantly. Immunofluorescent staining of vinculin in osteoblast cells showed good focal contact adhesion on the CrAlSiN and Ti thin films but not on the CrN thin films. Cell proliferation was significantly greater on the CrAlSiN thin films as well as on Ti thin films than on the CrN thin films.

Histomorphological differentiation of non-erosive reflux disease and functional heartburn in patients with PPI-refractory heartburn.

Science.gov (United States)

Kandulski, A; Jechorek, D; Caro, C; Weigt, J; Wex, T; Mönkemüller, K; Malfertheiner, P

2013-09-01

Proton pump inhibitor (PPI)-refractory heartburn may be due to persistent gastro-oesophageal reflux, oesophageal hypersensitivity or functional heartburn (FH). The differentiation between non-erosive reflux disease (NERD) and FH may be very difficult. However, this differentiation is important for appropriate therapeutic management. Dilated intercellular spaces (DIS), papillary elongation (PE) and basal cell hyperplasia (BCH) can be all assessed by light microscopy. Whether these mucosal abnormalities allow the differentiation of NERD from FH in PPI-refractory patients is uncertain. To assess histopathological findings by light microscopy in patients with refractory heartburn to differentiate NERD from FH. Sixty-two patients with PPI-refractory symptoms underwent EGD and MII-pH after pausing PPI medication for 2 weeks before investigation. Twenty-five subjects without upper gastrointestinal symptoms were included as controls. Symptom assessment was based on the reflux disease questionnaire (RDQ). Biopsies were taken 3-5 cm above the gastro-oesophageal junction. DIS, PE, BCH and infiltration of immune cells were evaluated and a sum score was calculated. Based on endoscopy and MII-pH, GERD was diagnosed in 43 patients (NERD: 20; ERD: 23) and FH in 19 patients. There was no difference in symptoms between the groups. Each individual histopathological item was different between the groups (P < 0.0001). Between NERD and FH, the most significant difference was found for DIS and the histopathological sum score (P < 0.001). These findings suggest that oesophageal biopsies are useful to differentiate NERD from FH. Increased DIS and a histological sum score are the most significant histopathological abnormalities in NERD as compared with FH. © 2013 John Wiley & Sons Ltd.

Choice vs. voice? PPI policies and the re‐positioning of the state in England and Wales