Atmospheric-Pressure-Spray, Chemical- Vapor-Deposited Thin-Film Materials Being Developed for High Power-to- Weight-Ratio Space Photovoltaic Applications

Science.gov (United States)

Hepp, Aloysius F.; Harris, Jerry D.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Smith, Mark A.; Cowen, Jonathan E.

2001-01-01

The key to achieving high specific power (watts per kilogram) space photovoltaic arrays is the development of high-efficiency thin-film solar cells that are fabricated on lightweight, space-qualified substrates such as Kapton (DuPont) or another polymer film. Cell efficiencies of 20 percent air mass zero (AM0) are required. One of the major obstacles to developing lightweight, flexible, thin-film solar cells is the unavailability of lightweight substrate or superstrate materials that are compatible with current deposition techniques. There are two solutions for working around this problem: (1) develop new substrate or superstrate materials that are compatible with current deposition techniques, or (2) develop new deposition techniques that are compatible with existing materials. The NASA Glenn Research Center has been focusing on the latter approach and has been developing a deposition technique for depositing thin-film absorbers at temperatures below 400 C.

Thin-Film Power Transformers

Science.gov (United States)

Katti, Romney R.

1995-01-01

Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

Thermal characterizations analysis of high-power ThinGaN cool-white light-emitting diodes

Science.gov (United States)

Raypah, Muna E.; Devarajan, Mutharasu; Ahmed, Anas A.; Sulaiman, Fauziah

2018-03-01

Analysis of thermal properties plays an important role in the thermal management of high-power (HP) lighting-emitting diodes (LEDs). Thermal resistance, thermal capacitance, and thermal time constant are essential parameters for the optimal design of the LED device and system, particularly for dynamic performance study. In this paper, thermal characterization and thermal time constant of ThinGaN HP LEDs are investigated. Three HP cool-white ThinGaN LEDs from different manufacturers are used in this study. A forward-voltage method using thermal transient tester (T3Ster) system is employed to determine the LEDs' thermal parameters at various operating conditions. The junction temperature transient response is described by a multi-exponential function model to extract thermal time constants. The transient response curve is divided into three layers and expressed by three exponential functions. Each layer is associated with a particular thermal time constant, thermal resistance, and thermal capacitance. It is found that the thermal time constant of LED package is on the order of 22 to 100 ms. Comparison between the experimental results is carried out to show the design effects on thermal performance of the LED package.

Investigation of the High Mobility IGZO Thin Films by Using Co-Sputtering Method

Science.gov (United States)

Hsu, Chao-Ming; Tzou, Wen-Cheng; Yang, Cheng-Fu; Liou, Yu-Jhen

2015-01-01

High transmittance ratio in visible range, low resistivity, and high mobility of IGZO thin films were prepared at room temperature for 30 min by co-sputtering of Zn2Ga2O5 (Ga2O3 + 2 ZnO, GZO) ceramic and In2O3 ceramic at the same time. The deposition power of pure In2O3 ceramic target was fixed at 100 W and the deposition power of GZO ceramic target was changed from 80 W to 140 W. We chose to investigate the deposition power of GZO ceramic target on the properties of IGZO thin films. From the SEM observations, all of the deposited IGZO thin films showed a very smooth and featureless surface. From the measurements of XRD patterns, only the amorphous structure was observed. We aimed to show that the deposition power of GZO ceramic target had large effect on the Eg values, Hall mobility, carrier concentration, and resistivity of IGZO thin films. Secondary ion mass spectrometry (SIMS) analysis in the thicknesses’ profile of IGZO thin films found that In and Ga elements were uniform distribution and Zn element were non-uniform distribution. The SIMS analysis results also showed the concentrations of Ga and Zn elements increased and the concentrations of In element was almost unchanged with increasing deposition power.

Investigation of the High Mobility IGZO Thin Films by Using Co-Sputtering Method

Directory of Open Access Journals (Sweden)

Chao-Ming Hsu

2015-05-01

Full Text Available High transmittance ratio in visible range, low resistivity, and high mobility of IGZO thin films were prepared at room temperature for 30 min by co-sputtering of Zn2Ga2O5 (Ga2O3 + 2 ZnO, GZO ceramic and In2O3 ceramic at the same time. The deposition power of pure In2O3 ceramic target was fixed at 100 W and the deposition power of GZO ceramic target was changed from 80 W to 140 W. We chose to investigate the deposition power of GZO ceramic target on the properties of IGZO thin films. From the SEM observations, all of the deposited IGZO thin films showed a very smooth and featureless surface. From the measurements of XRD patterns, only the amorphous structure was observed. We aimed to show that the deposition power of GZO ceramic target had large effect on the Eg values, Hall mobility, carrier concentration, and resistivity of IGZO thin films. Secondary ion mass spectrometry (SIMS analysis in the thicknesses’ profile of IGZO thin films found that In and Ga elements were uniform distribution and Zn element were non-uniform distribution. The SIMS analysis results also showed the concentrations of Ga and Zn elements increased and the concentrations of In element was almost unchanged with increasing deposition power.

High Power High Thrust Ion Thruster (HPHTion): 50 CM Ion Thruster for Near-Earth Applications, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Advances in high power, photovoltaic technology has enabled the possibility of reasonably sized, high specific power, high power, solar arrays. New thin film solar...

Influence of sputtering power on the optical properties of ITO thin films

Energy Technology Data Exchange (ETDEWEB)

K, Aijo John; M, Deepak, E-mail: manju.thankamoni@gmail.com; T, Manju, E-mail: manju.thankamoni@gmail.com [Department of Physics, Sree Sankara College, Kalady P. O., Ernakulam Dist., Kerala (India); Kumar, Vineetha V. [Dept. of Physics, K. E. College, Mannanam, Kottayam Dist., Kerala (India)

2014-10-15

Tin doped indium oxide films are widely used in transparent conducting coatings such as flat panel displays, crystal displays and in optical devices such as solar cells and organic light emitting diodes due to the high electrical resistivity and optical transparency in the visible region of solar spectrum. The deposition parameters have a commendable influence on the optical and electrical properties of the thin films. In this study, ITO thin films were prepared by RF magnetron sputtering. The properties of the films prepared under varying sputtering power were compared using UV- visible spectrophotometry. Effect of sputtering power on the energy band gap, absorption coefficient and refractive index are investigated.

Highly-efficient, flexible piezoelectric PZT thin film nanogenerator on plastic substrates.

Science.gov (United States)

Park, Kwi-Il; Son, Jung Hwan; Hwang, Geon-Tae; Jeong, Chang Kyu; Ryu, Jungho; Koo, Min; Choi, Insung; Lee, Seung Hyun; Byun, Myunghwan; Wang, Zhong Lin; Lee, Keon Jae

2014-04-23

A highly-efficient, flexible piezoelectric PZT thin film nanogenerator is demonstrated using a laser lift-off (LLO) process. The PZT thin film nanogenerator harvests the highest output performance of ∼200 V and ∼150 μA·cm(-2) from regular bending motions. Furthermore, power sources generated from a PZT thin film nanogenerator, driven by slight human finger bending motions, successfully operate over 100 LEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of the High Mobility IGZO Thin Films by Using Co-Sputtering Method

OpenAIRE

Hsu, Chao-Ming; Tzou, Wen-Cheng; Yang, Cheng-Fu; Liou, Yu-Jhen

2015-01-01

High transmittance ratio in visible range, low resistivity, and high mobility of IGZO thin films were prepared at room temperature for 30 min by co-sputtering of Zn2Ga2O5 (Ga2O3 + 2 ZnO, GZO) ceramic and In2O3 ceramic at the same time. The deposition power of pure In2O3 ceramic target was fixed at 100 W and the deposition power of GZO ceramic target was changed from 80 W to 140 W. We chose to investigate the deposition power of GZO ceramic target on the properties of IGZO thin films. From the...

Sub-second photonic processing of solution-deposited single layer and heterojunction metal oxide thin-film transistors using a high-power xenon flash lamp

KAUST Repository

Tetzner, Kornelius; Lin, Yen-Hung; Regoutz, Anna; Seitkhan, Akmaral; Payne, David J.; Anthopoulos, Thomas D.

2017-01-01

We report the fabrication of solution-processed In2O3 and In2O3/ZnO heterojunction thin-film transistors (TFTs) where the precursor materials were converted to their semiconducting state using high power light pulses generated by a xenon flash lamp

Using high thermal stability flexible thin film thermoelectric generator at moderate temperature

Science.gov (United States)

Zheng, Zhuang-Hao; Luo, Jing-Ting; Chen, Tian-Bao; Zhang, Xiang-Hua; Liang, Guang-Xing; Fan, Ping

2018-04-01

Flexible thin film thermoelectric devices are extensively used in the microscale industry for powering wearable electronics. In this study, comprehensive optimization was conducted in materials and connection design for fabricating a high thermal stability flexible thin film thermoelectric generator. First, the thin films in the generator, including the electrodes, were prepared by magnetron sputtering deposition. The "NiCu-Cu-NiCu" multilayer electrode structure was applied to ensure the thermal stability of the device used at moderate temperature in an air atmosphere. A design with metal layer bonding and series accordant connection was then employed. The maximum efficiency of a single PN thermocouple generator is >11%, and the output power loss of the generator is <10% after integration.

Electrochemically synthesized nanocrystalline spinel thin film for high performance supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Gupta, Vinay [Carbon Technology Unit, Engineering Materials Division, National Physical Laboratory, New-Delhi, 110012 (India); Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan); Japan Science and Technology Agency, Kawaguchi-shi, Saitama, 332-0012 (Japan); Gupta, Shubhra; Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan)

2010-06-01

Spinels are not known for their supercapacitive nature. Here, we have explored electrochemically synthesized nanostructured NiCo{sub 2}O{sub 4} spinel thin-film electrode for electrochemical supercapacitors. The nanostructured NiCo{sub 2}O{sub 4} spinel thin film exhibited a high specific capacitance value of 580 F g{sup -1} and an energy density of 32 Wh kg{sup -1} at the power density of 4 kW kg{sup -1}, accompanying with good cyclic stability. (author)

A high-efficiency solution-deposited thin-film photovoltaic device

Energy Technology Data Exchange (ETDEWEB)

Mitzi, David B; Yuan, Min; Liu, Wei; Chey, S Jay; Schrott, Alex G [IBM T. J. Watson Research Center, Yorktown Heights, NY (United States); Kellock, Andrew J; Deline, Vaughn [IBM Almaden Research Center, San Jose, CA (United States)

2008-10-02

High-quality Cu(In,Ga)Se{sub 2} (CIGS) films are deposited from hydrazine-based solutions and are employed as absorber layers in thin-film photovoltaic devices. The CIGS films exhibit tunable stoichiometry and well-formed grain structure without requiring post-deposition high-temperature selenium treatment. Devices based on these films offer power conversion efficiencies of 10% (AM1.5 illumination). (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Characteristics of thin film fullerene coatings formed under different deposition conditions by power ion beams

International Nuclear Information System (INIS)

Petrov, A.V.; Ryabchikov, A.I.; Struts, V.K.; Usov, Yu.P.; Renk, T.J.

2007-01-01

Carbon allotropic form - C 60 and C 70 can be used in microelectronics, superconductors, solar batteries, logic and memory devices to increase processing tool wear resistance, as magnetic nanocomposite materials for record and storage information, in biology, medicine and pharmacology. In many cases it is necessary to have a thin-film containing C 60 and C 70 fullerene carbon coatings. A possibility in principle of thin carbon films formation with nanocrystalline structure and high content ∼30-95% of C 60 and C 70 fullerene mixture using the method of graphite targets sputtering by a power ion beam has been shown. Formation of thin-film containing C 60 and C 70 fullerene carbon coatings were carried out by means of deposition of ablation plasma on silicon substrates. Ablation plasma was generated as result of interaction of high-power pulsed ion beams (HPPIB) with graphite targets of different densities. It has been demonstrated that formation of fullerenes, their amount and characteristics of thin-film coatings depend on the deposition conditions. The key parameter for such process is the deposition rate, which determines thin film formation conditions and, subsequently, its structure and mechanical properties. Nano-hardness, Young module, adhesion to mono-crystalline silicon substrate, friction coefficient, roughness surface of synthesized coatings at the different deposition conditions were measured. These characteristics are under influence of such main process parameters as energy density of HPPIB, which, in turn, determinates the density and temperature of ablation plasma and deposition speed, which is thickness of film deposited for one pulse of ion current. Nano-hardness and Young module meanings are higher at the increasing of power density of ion beam. Adhesion value is less at the high deposition speed. As rule, friction coefficient depends on vice versa from roughness. (authors)

Microstructure of ZnO thin films deposited by high power impulse magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Reed, A.N., E-mail: amber.reed.5@us.af.mil [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469 (United States); Shamberger, P.J. [Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States); Hu, J.J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); University of Dayton Research Institute, University of Dayton, Dayton, OH 45469 (United States); Muratore, C. [Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469 (United States); Bultman, J.E. [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); University of Dayton Research Institute, University of Dayton, Dayton, OH 45469 (United States); Voevodin, A.A., E-mail: andrey.voevodin@us.af.mil [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States)

2015-03-31

High power impulse magnetron sputtering was used to deposit thin (~ 100 nm) zinc oxide (ZnO) films from a ceramic ZnO target onto substrates heated to 150 °C. The resulting films had strong crystallinity, highly aligned (002) texture and low surface roughness (root mean square roughness less than 10 nm), as determined by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and atomic force spectroscopy measurements. Deposition pressure and target–substrate distance had the greatest effect on film microstructure. The degree of alignment in the films was strongly dependent on the gas pressure. Deposition at pressures less than 0.93 Pa resulted in a bimodal distribution of grain sizes. An initial growth layer with preferred orientations (101) and (002) parallel to the interface was observed at the film–substrate interface under all conditions examined here; the extent of that competitive region was dependent on growth conditions. Time-resolved current measurements of the target and ion energy distributions, determined using energy resolved mass spectrometry, were correlated to film microstructure in order to investigate the effect of plasma conditions on film nucleation and growth. - Highlights: • Low temperature growth of nanocrystalline zinc oxide (ZnO) films. • ZnO films had a highly (002) textured, smooth, dense microstructure. • Dominant (002) orientation of films was pressure dependent. • Interfacial (101)/(002) mixed orientation layer controlled by substrate location.

Developing high-transmittance heterojunction diodes based on NiO/TZO bilayer thin films

Science.gov (United States)

2013-01-01

In this study, radio frequency magnetron sputtering was used to deposit nickel oxide thin films (NiO, deposition power of 100 W) and titanium-doped zinc oxide thin films (TZO, varying deposition powers) on glass substrates to form p(NiO)-n(TZO) heterojunction diodes with high transmittance. The structural, optical, and electrical properties of the TZO and NiO thin films and NiO/TZO heterojunction devices were investigated with scanning electron microscopy, X-ray diffraction (XRD) patterns, UV-visible spectroscopy, Hall effect analysis, and current-voltage (I-V) analysis. XRD analysis showed that only the (111) diffraction peak of NiO and the (002) and (004) diffraction peaks of TZO were observable in the NiO/TZO heterojunction devices, indicating that the TZO thin films showed a good c-axis orientation perpendicular to the glass substrates. When the sputtering deposition power for the TZO thin films was 100, 125, and 150 W, the I-V characteristics confirmed that a p-n junction characteristic was successfully formed in the NiO/TZO heterojunction devices. We show that the NiO/TZO heterojunction diode was dominated by the space-charge limited current theory. PMID:23634999

Structural and optical properties of zirconia thin films deposited by reactive high-power impulse magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaoli; Jin, Jie [Tianjin University, School of Electronic Information Engineering, Tianjin (China); Cheng, Jui-Ching, E-mail: juiching@ntut.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lee, Jyh-Wei [Ming Chi University of Technology, College of Materials Engineering, New Taipei City, Taiwan (China); Wu, Kuo-Hong [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lin, Kuo-Cheng; Tsai, Jung-Ruey [Asia University, Department of Photonics and Communication Engineering, Taichung, Taiwan (China); Liu, Kou-Chen, E-mail: jacobliu@mail.cgu.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China)

2014-11-03

Zirconia films are deposited by reactive high power impulse magnetron sputtering (HiPIMS) technology on glass and indium-tin-oxide (ITO)/glass substrates. Preparation, microstructure and optical characteristics of the films have been studied. During deposition, the influence of the target power and duty cycle on the peak current–voltage and power density has been observed in oxide mode. Transparent thin films under different oxygen proportions are obtained on the two substrates. Atomic force microscopy measurements showed that the surface roughness of the films was lower by reactive HiPIMS than DC sputtering for all oxygen contents. The transmission and reflectance properties of differently grown zirconia films were also investigated using an ultraviolet–visible spectrophotometer. The optical transmittance of films grown on glass substrates by HiPIMS reached maximum values above 90%, which exceeded that by DC sputtering. The band edge near 5.86 eV shifted to a lower wavelength for zirconia films prepared with oxygen flow rates lower than 4.5 sccm. For the films prepared on ITO/glass substrates, the transmittance and the band gap of zirconia films were limited by ITO films; a maximum average transmittance of 84% was obtained at 4.5 sccm O{sub 2} and the energy band gap was in the range of 3.7–3.8 eV for oxygen flow rates ranging from 3.5 to 5.0 sccm. Finally, the electrical properties of zirconia films have also been discussed. - Highlights: • Zirconia films are deposited by reactive high power impulse magnetron sputtering. • Low roughness films are obtained. • Films show a high transmittance (> 90%). • Films prepared on glass have a band gap of 5.9 eV.

Highly efficient 400  W near-fundamental-mode green thin-disk laser.

Science.gov (United States)

Piehler, Stefan; Dietrich, Tom; Rumpel, Martin; Graf, Thomas; Ahmed, Marwan Abdou

2016-01-01

We report on the efficient generation of continuous-wave, high-brightness green laser radiation. Green lasers are particularly interesting for reliable and reproducible deep-penetration welding of copper or for pumping Ti:Sa oscillators. By intracavity second-harmonic generation in a thin-disk laser resonator designed for fundamental-mode operation, an output power of up to 403 W is demonstrated at a wavelength of 515 nm with almost diffraction-limited beam quality. The unprecedented optical efficiency of 40.7% of green output power with respect to the pump power of the thin-disk laser is enabled by the intracavity use of a highly efficient grating waveguide mirror, which combines the functions of wavelength stabilization and spectral narrowing, as well as polarization selection in a single element.

Wavy channel Thin Film Transistor for area efficient, high performance and low power applications

KAUST Repository

Hanna, Amir

2014-06-01

We report a new Thin Film Transistor (TFT) architecture that allows expansion of the device width using wavy (continuous without separation) fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area efficiency. The devices have shown for a 13% increase in the device width resulting in a maximum 2.4x increase in \\'ON\\' current value of the WCTFT, when compared to planar devices consuming the same chip area, while using atomic layer deposition based zinc oxide (ZnO) as the channel material. The WCTFT devices also maintain similar \\'OFF\\' current value, similar to 100 pA, when compared to planar devices, thus not compromising on power consumption for performance which usually happens with larger width devices. This work offers a pragmatic opportunity to use WCTFTs as backplane circuitry for large-area high-resolution display applications without any limitation any TFT materials.

High Thermoelectric Power Factor Organic Thin Films through Combination of Nanotube Multilayer Assembly and Electrochemical Polymerization.

Science.gov (United States)

Culebras, Mario; Cho, Chungyeon; Krecker, Michelle; Smith, Ryan; Song, Yixuan; Gómez, Clara M; Cantarero, Andrés; Grunlan, Jaime C

2017-02-22

In an effort to produce effective thermoelectric nanocomposites with multiwalled carbon nanotubes (MWCNT), layer-by-layer assembly was combined with electrochemical polymerization to create synergy that would produce a high power factor. Nanolayers of MWCNT stabilized with poly(diallyldimethylammonium chloride) or sodium deoxycholate were alternately deposited from water. Poly(3,4-ethylene dioxythiophene) [PEDOT] was then synthesized electrochemically by using this MWCNT-based multilayer thin film as the working electrode. Microscopic images show a homogeneous distribution of PEDOT around the MWCNT. The electrical resistance, conductivity (σ) and Seebeck coefficient (S) were measured before and after the PEDOT polymerization. A 30 bilayer MWCNT film (<1 μm thick) infused with PEDOT is shown to achieve a power factor (PF = S 2 σ) of 155 μW/m K 2 , which is the highest value ever reported for a completely organic MWCNT-based material and competitive with lead telluride at room temperature. The ability of this MWCNT-PEDOT film to generate power was demonstrated with a cylindrical thermoelectric generator that produced 5.5 μW with a 30 K temperature differential. This unique nanocomposite, prepared from water with relatively inexpensive ingredients, should open up new opportunities to recycle waste heat in portable/wearable electronics and other applications where low weight and mechanical flexibility are needed.

Domain Engineered Magnetoelectric Thin Films for High Sensitivity Resonant Magnetic Field Sensors

Science.gov (United States)

2011-12-01

band gap of highly textured PZT thin films. The deposition process variables were - argon and oxygen flows, chamber pressure, RF power (DC Bias...needed another parameter to equate with the number of unknowns in the resultant model equations. From Figure 24, electronic polarizability affects the... Polarizability and Optical dielectric response of a thin.film , ., ,__~--~---\\- 000 01’ "󈧶 Ots Tncnt.re"’°l Effective Polarizability = Reddy

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

International Nuclear Information System (INIS)

Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M.

2013-01-01

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

KAUST Repository

Hanna, Amir; Ghoneim, Mohamed T.; Bahabry, Rabab R.; Hussain, Aftab M.; Hussain, Muhammad Mustafa

2013-01-01

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

KAUST Repository

Hanna, Amir

2013-11-26

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

Advances in thin-film solar cells for lightweight space photovoltaic power

Science.gov (United States)

Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

1989-01-01

The development of photovoltaic arrays beyond the next generation is discussed with attention given to the potentials of thin-film polycrystalline and amorphous cells. Of particular importance is the efficiency (the fraction of incident solar energy converted to electricity) and specific power (power to weight ratio). It is found that the radiation tolerance of thin-film materials is far greater than that of single crystal materials. CuInSe2 shows no degradation when exposed to 1-MeV electrons.

Development of a thin film solar cell interconnect for the PowerSphere concept

International Nuclear Information System (INIS)

Simburger, Edward J.; Matsumoto, James H.; Giants, Thomas W.; Garcia, Alexander; Liu, Simon; Rawal, Suraj P.; Perry, Alan R.; Marshall, Craig H.; Lin, John K.; Scarborough, Stephen E.; Curtis, Henry B.; Kerslake, Thomas W.; Peterson, Todd T.

2005-01-01

Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the PowerSphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference

Wavy channel thin film transistor architecture for area efficient, high performance and low power displays

KAUST Repository

Hanna, Amir

2013-12-23

We demonstrate a new thin film transistor (TFT) architecture that allows expansion of the device width using continuous fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area efficiency. The devices have shown for a 13% increase in the device width resulting in a maximum 2.5× increase in \\'ON\\' current value of the WCTFT, when compared to planar devices consuming the same chip area, while using atomic layer deposition based zinc oxide (ZnO) as the channel material. The WCTFT devices also maintain similar \\'OFF\\' current value, ~100 pA, when compared to planar devices, thus not compromising on power consumption for performance which usually happens with larger width devices. This work offers an interesting opportunity to use WCTFTs as backplane circuitry for large-area high-resolution display applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance thin-film composite forward osmosis membrane.

Science.gov (United States)

Yip, Ngai Yin; Tiraferri, Alberto; Phillip, William A; Schiffman, Jessica D; Elimelech, Menachem

2010-05-15

Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 mum) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m(2-)h(-1), while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution.

High Performance Thin-Film Composite Forward Osmosis Membrane

KAUST Repository

Yip, Ngai Yin

2010-05-15

Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 μm) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m2-h-1, while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution. © 2010 American Chemical Society.

High-frequency electromagnetic properties of soft magnetic metal-polyimide hybrid thin films

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Woo [Nano-Materials Research Center, Korea Institute of Science and Technology, 39-1 Haweoulgog-dong, Sungbuk-gu, Seoul 136-791 (Korea, Republic of)]. E-mail: swkim@kist.re.kr; Yoon, Chong S. [Division of Advanced Materials Science, Hanyang University, Seoul 133-791 (Korea, Republic of)

2007-09-15

Although there are a lot of demands for suppression of unwanted high-frequency electromagnetic noise in highly integrated electronic devices such as mobile phones and notebook computers, electromagnetic thin films that effectively work in the high-frequency range have still been underdeveloped. Soft magnetic metal-polyimide (PI) hybrid films with high electrical resistivity were prepared by thermal imidization and selective oxidation between the metal alloy layer and polyamic acid (PAA) layer. Electromagnetic properties of the hybrid thin films in the radio-frequency range were characterized by using the microstrip line method and were correlated with their material parameters. Although anisotropy field of the CoFe/NiFe hybrid film was two times lower than that of the NiFe hybrid film, the saturation magnetization of the CoFe/NiFe hybrid film was three times higher than that of the NiFe hybrid film. The CoFe/NiFe hybrid film showed higher power loss in the frequency range of 3-6 GHz compared to the NiFe hybrid film. The high power loss of the CoFe/NiFe hybrid film was caused by high relative permeability and high ferromagnetic resonance (FMR) frequency due to high saturation magnetization.

High-frequency electromagnetic properties of soft magnetic metal-polyimide hybrid thin films

International Nuclear Information System (INIS)

Kim, Sang Woo; Yoon, Chong S.

2007-01-01

Although there are a lot of demands for suppression of unwanted high-frequency electromagnetic noise in highly integrated electronic devices such as mobile phones and notebook computers, electromagnetic thin films that effectively work in the high-frequency range have still been underdeveloped. Soft magnetic metal-polyimide (PI) hybrid films with high electrical resistivity were prepared by thermal imidization and selective oxidation between the metal alloy layer and polyamic acid (PAA) layer. Electromagnetic properties of the hybrid thin films in the radio-frequency range were characterized by using the microstrip line method and were correlated with their material parameters. Although anisotropy field of the CoFe/NiFe hybrid film was two times lower than that of the NiFe hybrid film, the saturation magnetization of the CoFe/NiFe hybrid film was three times higher than that of the NiFe hybrid film. The CoFe/NiFe hybrid film showed higher power loss in the frequency range of 3-6 GHz compared to the NiFe hybrid film. The high power loss of the CoFe/NiFe hybrid film was caused by high relative permeability and high ferromagnetic resonance (FMR) frequency due to high saturation magnetization

High energy density capacitors fabricated by thin film technology

International Nuclear Information System (INIS)

Barbee, T W; Johnson, G W; Wagner, A V.

1999-01-01

Low energy density in conventional capacitors severely limits efforts to miniaturize power electronics and imposes design limitations on electronics in general. We have successfully applied physical vapor deposition technology to greatly increase capacitor energy density. The high dielectric breakdown strength we have achieved in alumina thin films allows high energy density to be achieved with this moderately low dielectric constant material. The small temperature dependence of the dielectric constant, and the high reliability, high resistivity, and low dielectric loss of Al 2 O 3 , make it even more appealing. We have constructed single dielectric layer thin film capacitors and shown that they can be stacked to form multilayered structures with no loss in yield for a given capacitance. Control of film growth morphology is critical for achieving the smooth, high quality interfaces between metal and dielectric necessary for device operation at high electric fields. Most importantly, high rate deposition with extremely low particle generation is essential for achieving high energy storage at a reasonable cost. This has been achieved by reactive magnetron sputtering in which the reaction to form the dielectric oxide has been confined to the deposition surface. By this technique we have achieved a yield of over 50% for 1 cm 2 devices with an energy density of 14 J per cubic centimeter of Al 2 O 3 dielectric material in 1.2 kV, 4 nF devices. By further reducing defect density and increasing the dielectric constant of the material, we will be able to increase capacitance and construct high energy density devices to meet the requirements of applications in power electronics

DEVICE TECHNOLOGY. Nanomaterials in transistors: From high-performance to thin-film applications.

Science.gov (United States)

Franklin, Aaron D

2015-08-14

For more than 50 years, silicon transistors have been continuously shrunk to meet the projections of Moore's law but are now reaching fundamental limits on speed and power use. With these limits at hand, nanomaterials offer great promise for improving transistor performance and adding new applications through the coming decades. With different transistors needed in everything from high-performance servers to thin-film display backplanes, it is important to understand the targeted application needs when considering new material options. Here the distinction between high-performance and thin-film transistors is reviewed, along with the benefits and challenges to using nanomaterials in such transistors. In particular, progress on carbon nanotubes, as well as graphene and related materials (including transition metal dichalcogenides and X-enes), outlines the advances and further research needed to enable their use in transistors for high-performance computing, thin films, or completely new technologies such as flexible and transparent devices. Copyright © 2015, American Association for the Advancement of Science.

Effect of R.F. Power to the Structural Properties of ZnO Thin Films Deposited by Magnetron Sputtering

International Nuclear Information System (INIS)

Sin, N.D.M.; Rusop, M.

2011-01-01

The effect of RF power variation (100 watt∼400 watt ) on the zinc oxide (ZnO) thin films electrical, optical and structural properties were examined using current voltage (I-V) measurement, UV-Vis-NIR spectrophotometer, x-ray diffraction (XRD) and atomic force microscope (AFM). ZnO thin films were prepared at room temperature in pure argon atmosphere by a RF magnetron sputtering using ZnO target. The resistivity of thin film show the lowest at 300 watt. The absorption coefficient spectra obtained from UV-Vis-NIR spectrophotometer measurement show all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties using UV-VIS spectrophotometer (JASCO 670) . Highly oriented ZnO thin films [002] direction were obtained by using Rigaku Ultima IV. (author)

Effect of Different Deposition Power of In2O3 Target on the Characteristics of IGZO Thin Films Using the Cosputtering Method

Directory of Open Access Journals (Sweden)

Shang-Chao Hung

2014-01-01

Full Text Available The (In, Ga, ZnOx (IGZO thin films were deposited on glass substrates using cosputtering method in radio frequency magnetron sputtering system. Zn2Ga2O5 (Ga2O3-2 ZnO, GZO and In2O3 ceramics were used as targets and dual guns were used to deposit the IGZO thin films. Deposition power of GZO target was 80 W and deposition power of pure In2O3 target was changed from 70 W to 100 W, and the deposition time was 30 min. The effect of deposition power of In2O3 target on the crystalline, surface, electrical, and optical properties of the IGZO thin films was investigated at room temperature in a pure Ar atmosphere. The cosputtered IGZO thin films showed a very smooth and featureless surface and an amorphous structure regardless of the deposition power of In2O3 target due to the room temperature sputtering process. However, the cosputtered IGZO thin films exhibited transparent electrode properties because they had high transmittance ratio and low resistivity. The value variations in the optical band gap (Eg values of the IGZO thin film were evaluated from the plots of (αhν2=c(hν-Eg. We would also show that the deposition power of In2O3 target would have a large effect on mobility and Eg value of the IGZO thin films.

High power density carbonate fuel cell

Energy Technology Data Exchange (ETDEWEB)

Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)

1996-12-31

Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

Timing A Pulsed Thin Film Pyroelectric Generator For Maximum Power Density

International Nuclear Information System (INIS)

Smith, A.N.; Hanrahan, B.M.; Neville, C.J.; Jankowski, N.R

2016-01-01

Pyroelectric thermal-to-electric energy conversion is accomplished by a cyclic process of thermally-inducing polarization changes in the material under an applied electric field. The pyroelectric MEMS device investigated consisted of a thin film PZT capacitor with platinum bottom and iridium oxide top electrodes. Electric fields between 1-20 kV/cm with a 30% duty cycle and frequencies from 0.1 - 100 Hz were tested with a modulated continuous wave IR laser with a duty cycle of 20% creating temperature swings from 0.15 - 26 °C on the pyroelectric receiver. The net output power of the device was highly sensitive to the phase delay between the laser power and the applied electric field. A thermal model was developed to predict and explain the power loss associated with finite charge and discharge times. Excellent agreement was achieved between the theoretical model and the experiment results for the measured power density versus phase delay. Limitations on the charging and discharging rates result in reduced power and lower efficiency due to a reduced net work per cycle. (paper)

High-power diode-pumped Nd:Lu2O3 crystal continuous-wave thin-disk laser at 1359 nm

International Nuclear Information System (INIS)

Li, J H; Liu, X H; Wu, J B; Zhang, X; Li, Y L

2012-01-01

We present for the first time, to the best of our knowledge, a 1359 nm continuous-wave (CW) Nd:Lu 2 O 3 laser based on the 4 F 5/2 – 4 F 13/2 transition. The use of a pump module with 16 passes through the crystal allowed the realization of a Nd:Lu 2 O 3 thin-disk laser with 3.52 W of CW output power. The slope efficiency with respect to the incident pump power was 21.4%, and the fluctuation of the output power was better than 3.55% in the given 2 hour. The beam quality factor M 2 is 1.14 and 1.18 for tangential direction and sagittal direction, respectively

High thermoelectric power factor from multilayer solution-processed organic films

Science.gov (United States)

Zuo, Guangzheng; Andersson, Olof; Abdalla, Hassan; Kemerink, Martijn

2018-02-01

We investigate the suitability of the "sequential doping" method of organic semiconductors for thermoelectric applications. The method consists of depositing a dopant (F4TCNQ) containing solution on a previously cast semiconductor (P3HT) thin film to achieve high conductivity, while preserving the morphology. For very thin films (˜25 nm), we achieve a high power factor around 8 μW/mK-2 with a conductivity over 500 S/m. For the increasing film thickness, conductivity and power factor show a decreasing trend, which we attribute to the inability to dope the deeper parts of the film. Since thick films are required to extract significant power from thermoelectric generators, we developed a simple additive technique that allows the deposition of an arbitrary number of layers without significant loss in conductivity or power factor that, for 5 subsequent layers, remain at ˜300 S/m and ˜5 μW/mK-2, respectively, whereas the power output increases almost one order of magnitude as compared to a single layer. The efficient doping in multilayers is further confirmed by an increased intensity of (bi)polaronic features in the UV-Vis spectra.

Enhancing Plasma Surface Modification using high Intensity and high Power Ultrasonic Acoustic Waves

DEFF Research Database (Denmark)

2010-01-01

high intensity and high power acoustic waves (102) by at least one ultrasonic high intensity and high power acoustic wave generator (101 ), wherein the ultrasonic acoustic waves are directed to propagate towards said surface (314) of the object (100) so that a laminar boundary layer (313) of a gas...... or a mixture of gases (500) flow in contact with said solid object (100) is thinned or destructed for at least a part of said surface (314). In this way, the plasma can more efficiently access and influence the surface of the solid object to be treated by the plasma, which speeds the process time up...

Nanogenerator-based dual-functional and self-powered thin patch loudspeaker or microphone for flexible electronics

Science.gov (United States)

Li, Wei; Torres, David; Díaz, Ramón; Wang, Zhengjun; Wu, Changsheng; Wang, Chuan; Lin Wang, Zhong; Sepúlveda, Nelson

2017-05-01

Ferroelectret nanogenerators were recently introduced as a promising alternative technology for harvesting kinetic energy. Here we report the device's intrinsic properties that allow for the bidirectional conversion of energy between electrical and mechanical domains; thus extending its potential use in wearable electronics beyond the power generation realm. This electromechanical coupling, combined with their flexibility and thin film-like form, bestows dual-functional transducing capabilities to the device that are used in this work to demonstrate its use as a thin, wearable and self-powered loudspeaker or microphone patch. To determine the device's performance and applicability, sound pressure level is characterized in both space and frequency domains for three different configurations. The confirmed device's high performance is further validated through its integration in three different systems: a music-playing flag, a sound recording film and a flexible microphone for security applications.

Advances in High-Power, Ultrashort Pulse DPSSL Technologies at HiLASE

Directory of Open Access Journals (Sweden)

Martin Smrž

2017-10-01

Full Text Available The development of kW-class diode-pumped picosecond laser sources emitting at various wavelengths started at the HiLASE Center four years ago. A 500-W Perla C thin-disk laser with a diffraction limited beam and repetition rate of 50–100 kHz, a frequency conversion to mid-infrared (mid-IR, and second to fifth harmonic frequencies was demonstrated. We present an updated review on the progress in the development of compact picosecond and femtosecond high average power radiation sources covering the ultraviolet (UV to mid-IR spectral range at the HiLASE Center. We also report on thin-disk manufacturing by atomic diffusion bonding, which is a crucial technology for future high-power laser development.

Thin-plate-type embedded ultrasonic transducer based on magnetostriction for the thickness monitoring of the secondary piping system of a nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Heo, Tae Hoon; Cho, Seung Hyun [Center for Safety Measurement, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2016-12-15

Pipe wall thinning in the secondary piping system of a nuclear power plant is currently a major problem that typically affects the safety and reliability of the nuclear power plant directly. Regular in-service inspections are carried out to manage the piping system only during the overhaul. Online thickness monitoring is necessary to avoid abrupt breakage due to wall thinning. To this end, a transducer that can withstand a high-temperature environment and should be installed under the insulation layer. We propose a thin plate type of embedded ultrasonic transducer based on magnetostriction. The transducer was designed and fabricated to measure the thickness of a pipe under a high-temperature condition. A number of experimental results confirmed the validity of the present transducer.

High-power ultrashort fiber laser for solar cells micromachining

Science.gov (United States)

Lecourt, J.-B.; Duterte, C.; Liegeois, F.; Lekime, D.; Hernandez, Y.; Giannone, D.

2012-02-01

We report on a high-power ultra-short fiber laser for thin film solar cells micromachining. The laser is based on Chirped Pulse Amplification (CPA) scheme. The pulses are stretched to hundreds of picoseconds prior to amplification and can be compressed down to picosecond at high energy. The repetition rate is adjustable from 100 kHz to 1 MHz and the optical average output power is close to 13 W (before compression). The whole setup is fully fibred, except the compressor achieved with bulk gratings, resulting on a compact and reliable solution for cold ablation.

Investigation of plasma stream collision produced by thin films irradiated by powerful pulsed electron beam

International Nuclear Information System (INIS)

Efremov, V P; Demidov, B A; Ivkin, M V; Mescheryakov, A N; Petrov, V A; Potapenko, A I

2006-01-01

Collision of fast plasma streams in vacuum is investigated. Plasma streams were produced by irradiation of thin foils with a powerful pulsed electron beam. Interaction of the plasma flows was studied by using frame and streak cameras. One-dimensional numerical simulation was carried out. Application of this method for porous ICF targets and high-energy physics is discussed

Trend of field data on pipe wall thinning for BWR power plants

International Nuclear Information System (INIS)

Hakii, Junichi; Hiranuma, Naoki; Hidaka, Akitaka

2009-01-01

Strongly motivated by every stakeholder not to repeat Mihama Nuclear Power Station pipe rupture accident in August 2004, JSME Main Committee on Codes and Standards on Power Generation Facilities immediately launched a special task force to develop Rules on Pipe Wall Thinning Management for BWR, PWR and fossil Power Plants respectively. The authors describes the process of the development of Rules for BWR Power Plans from the view point of collections and analysis of fields data of pipe wall thinning. Through its activities, the authors confirmed the existing findings, like the effect of Oxygen injection, turbulence and dependence on coolant temperature, derived from series of laboratory-scaled experiments in FAC and coolant velocities effects in LDI. Further based upon the said proven findings with field data, they explain the adequacy of major concept of the rule such as separate treatment of FAC (Flow Accelerated Corrosion) and LDI (Liquid Droplet Impingement). (author)

Outer-selective thin film composite (TFC) hollow fiber membranes for osmotic power generation

KAUST Repository

Le, Ngoc Lieu

2016-01-14

The pressure-retarded osmosis (PRO) process is a green technique for power generation to respond the world\\'s need of energy sustainability. In this study, we have developed the vital component of the process, i.e. membrane, in the configuration of the outer-selective thin-film composite (TFC) hollow fiber, which is more practical than other configurations in the real applications. The support layer morphology and the formation of the selective polyamide layer have been optimized for a good PRO performance. The results show that the bore fluid with higher amount of the solvent N-methyl-2-pyrrolidone leads to full finger-like hollow fibers, which provide higher flux but lower pressure tolerance. The addition of higher amount of diethylene glycol into the dope solution, improves the pore formation and suppresses the macrovoid formation, while properly lowering the take-up speed increases their wall thickness and pressure tolerance. A simple alcohol-pre-wetting approach on the fiber support leads to a smooth and thin polyamide layer, which is favorable for a high water flux and power density. Its efficiency follows this order: n-propanol>ethanol>methanol>water. The n-propanol pre-wetted TFC membrane can tolerate 17 bar with a peak power density of 9.59 W/m2 at room temperature, using 1 M NaCl solution as the draw solution and DI water as feed. This work demonstrates the potential of outer-selective TFC hollow fiber membranes for energy conversion via PRO process, provides useful database to fabricate suitable support morphology and raise a simple technique to practically form a thin and smooth polyamide layer.

High power density supercapacitor electrodes of carbon nanotube films by electrophoretic deposition

International Nuclear Information System (INIS)

Du Chunsheng; Pan Ning

2006-01-01

Carbon nanotube thin films have been successfully fabricated by the electrophoretic deposition technique. The supercapacitors built from such thin film electrodes have a very small equivalent series resistance, and a high specific power density over 20 kW kg -1 was thus obtained. More importantly, the supercapacitors showed superior frequency response. Our study also demonstrated that these carbon nanotube thin films can serve as coating layers over ordinary current collectors to drastically enhance the electrode performance, indicating a huge potential in supercapacitor and battery manufacturing

Variations in thermoelectric power of thin monocrystalline films with conductivity

Science.gov (United States)

Tellier, C. R.; Tosser, A. J.; Hafid, L.

1980-12-01

Starting from the bi-dimensional model for grain boundaries in monocrystalline thin films, the difference in thermoelectric power is expressed in terms of conductivity and energy dependence of the bulk electronic mean free path U. A new procedure is suggested for measuring U.

Synthesis of ultra-thin tellurium nanoflakes on textiles for high-performance flexible and wearable nanogenerators

Energy Technology Data Exchange (ETDEWEB)

He, Wen; Van Ngoc, Huynh; Qian, Yong Teng; Hwang, Jae Seok; Yan, Ya Ping [Department of Physics and Interdisciplinary Course of Physics and Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do (Korea, Republic of); Choi, Hongsoo [Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-873, Daegu (Korea, Republic of); Kang, Dae Joon, E-mail: djkang@skku.edu [Department of Physics and Interdisciplinary Course of Physics and Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do (Korea, Republic of)

2017-01-15

Highlights: • Ultra-thin tellurium (Te) nanoflakes were successfully grown on textile and used as an active piezoelectric material. • Te nanoflake nanogenerator device was systematically studied by bending and compressing test. • The ultra-high output power during compressing test can light up 10 LEDs without any external power source. • The device can offer a breakthrough in applying tellurium nanoflakes into high-performance flexible and wearable piezoelectric nanogenerator. - Abstract: We report that ultra-thin tellurium (Te) nanoflakes were successfully grown on a sample of a gold-coated textile, which then was used as an active piezoelectric material. An output voltage of 4 V and a current of 300 nA were obtained from the bending test under a driving frequency of 10 Hz. To test the practical applications, Te nanoflake nanogenerator (TFNG) device was attached to the subject’s arm, and mechanical energy was converted to electrical energy by means of periodic arm-bending motions. The optimized open-circuit voltage and short-circuit current density of approximately 125 V and 17 μA/cm{sup 2}, respectively, were observed when a TFNG device underwent a compression test with a compressive force of 8 N and driving frequency of 10 Hz. This high-power generation enabled the instantaneous powering of 10 green light-emitting diodes that shone without any assistance from an external power source.

Moderate high power 1 to 20μs and kHz Ho:YAG thin disk laser pulses for laser lithotripsy

Science.gov (United States)

Renz, Günther

2015-02-01

An acousto-optically or self-oscillation pulsed thin disk Ho:YAG laser system at 2.1 μm with an average power in the 10 W range will be presented for laser lithotripsy. In the case of cw operation the thin disk Ho:YAG is either pumped with InP diode stacks or with a thulium fiber laser which leads to a laser output power of 20 W at an optical-to-optical efficiency of 30%. For the gain switched mode of operation a modulated Tm-fiber laser is used to produce self-oscillation pulses. A favored pulse lengths for uric acid stone ablation is known to be at a few μs pulse duration which can be delivered by the thin disk laser technology. In the state of the art laser lithotripter, stone material is typically ablated with 250 to 750 μs pulses at 5 to 10 Hz and with pulse energies up to a few Joule. The ablation mechanism is performed in this case by vaporization into stone dust and fragmentation. With the thin disk laser technology, 1 to 20 μs-laser pulses with a repetition rate of a few kHz and with pulse energies in the mJ-range are available. The ablation mechanism is in this case due to a local heating of the stone material with a decomposition of the crystalline structure into calcium carbonate powder which can be handled by the human body. As a joint process to this thermal effect, imploding water vapor bubbles between the fiber end and the stone material produce sporadic shock waves which help clear out the stone dust and biological material.

New Methods for Thin Film Deposition and First Investigations of the use of High Temperature Superconductors for Thin Film Cavities

CERN Document Server

Gustafsson, Anna; Vollenberg, Wilhelmus; Seviour, Rebecca

2010-01-01

Niobium thin film cavities have shown good and reliable performance for LEP and LHC, although there are limitations to overcome if this technique should be used for new accelerators such as the ILC. New coating techniques like High Power Impulse Magnetron Sputtering (HiPIMS) has shown very promising results and we will report on its possible improvements for Nb thin film cavity performance. Current materials used in accelerator Superconducting Radio Frequency (SRF) technologies operate at temperatures below 4 K, which require complex cryogenic systems. Researchers have investigated the use of High Temperature Superconductors (HTS) to form RF cavities, with limited success. We propose a new approach to achieve a high-temperature SRF cavity based on the superconducting ’proximity effect’. The superconducting proximity effect is the effect through which a superconducting material in close proximity to a non-superconducting material induces a superconducting condensate in the latter. Using this effect we hope...

Industrial applications of high-average power high-peak power nanosecond pulse duration Nd:YAG lasers

Science.gov (United States)

Harrison, Paul M.; Ellwi, Samir

2009-02-01

Within the vast range of laser materials processing applications, every type of successful commercial laser has been driven by a major industrial process. For high average power, high peak power, nanosecond pulse duration Nd:YAG DPSS lasers, the enabling process is high speed surface engineering. This includes applications such as thin film patterning and selective coating removal in markets such as the flat panel displays (FPD), solar and automotive industries. Applications such as these tend to require working spots that have uniform intensity distribution using specific shapes and dimensions, so a range of innovative beam delivery systems have been developed that convert the gaussian beam shape produced by the laser into a range of rectangular and/or shaped spots, as required by demands of each project. In this paper the authors will discuss the key parameters of this type of laser and examine why they are important for high speed surface engineering projects, and how they affect the underlying laser-material interaction and the removal mechanism. Several case studies will be considered in the FPD and solar markets, exploring the close link between the application, the key laser characteristics and the beam delivery system that link these together.

Effect of target power on the physical properties of Ti thin films prepared by DC magnetron sputtering with supported discharge

Directory of Open Access Journals (Sweden)

Kavitha A.

2017-02-01

Full Text Available The present paper describes the effect of target power on the properties of Ti thin films prepared by DC magnetron sputtering with (triode mode and without (diode mode supported discharge. The traditional diode magnetron sputtering with an addition of a hot filament has been used to sustain the discharge at a lower pressure. The effect of target power (60, 80, 100 and 120 W on the physical properties of Ti thin films has been studied in diode and triode modes. XRD studies showed that the Ti thin films prepared at a target power up to 100 W in diode mode were amorphous in nature. The Ti thin films exhibited crystalline structure at much lower target power of 80 W with a preferred orientation along (0 0 2 plane. The grain size of Ti thin films prepared in triode mode increased from 64 nm to 80 nm, whereas in diode mode, the grain size increased from 2 nm to 5 nm. EDAX analysis confirmed that the incorporation of reactive gases was lower in triode mode compared to diode mode. The electrical resistivity of Ti thin films deposited in diode mode was found to be 85 µΩ⋅cm (target power 120 W. The electrical resistivity of Ti thin films in triode mode was found to be deceased to 15.2 µΩ⋅cm (target power 120 W.

A study on the shell wall thinning causes identified through experiment, numerical analysis and ultrasonic test of high-pressure feedwater heater

International Nuclear Information System (INIS)

Hwang, Kyeong Mo; Woo, Lee; Jin, Tae Eun; Kim, Kyung Hoon

2008-01-01

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which accelerates as the operation progresses. Several nuclear power plants in Korea have undergone this damage around the impingement baffle - installed downstream of the high-pressure turbine extraction steam line - inside numbers 5A and 5B feedwater heaters. At that point, the extracted steam from the high-pressure turbine consists in the form of two-phase fluid at high temperature, high pressure and high velocity. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of number 5 high-pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes the comparisons between the numerical analysis results using the FLUENT code and the downscaled experimental data in an effort to determine root causes of the shell wall thinning of the high-pressure feedwater heaters. The numerical analysis and experimental data were also confirmed by the actual wall thickness measured by ultrasonic tests. From the comparison of the results for the local velocity profiles and the wall thinning measurements, the local velocity component only in the y-direction flowing vertically to the shell wall, and not in the x- and z-directions, was analogous to the wall thinning data

Deposition of thin films and surface modification by pulsed high energy density plasma

International Nuclear Information System (INIS)

Yan Pengxun; Yang Size

2002-01-01

The use of pulsed high energy density plasma is a new low temperature plasma technology for material surface treatment and thin film deposition. The authors present detailed theoretical and experimental studies of the production mechanism and physical properties of the pulsed plasma. The basic physics of the pulsed plasma-material interaction has been investigated. Diagnostic measurements show that the pulsed plasma has a high electron temperature of 10-100 eV, density of 10 14 -10 16 cm -3 , translation velocity of ∼10 -7 cm/s and power density of ∼10 4 W/cm 2 . Its use in material surface treatment combines the effects of laser surface treatment, electron beam treatment, shock wave bombardment, ion implantation, sputtering deposition and chemical vapor deposition. The metastable phase and other kinds of compounds can be produced on low temperature substrates. For thin film deposition, a high deposition ratio and strong film to substrate adhesion can be achieved. The thin film deposition and material surface modification by the pulsed plasma and related physical mechanism have been investigated. Thin film c-BN, Ti(CN), TiN, DLC and AlN materials have been produced successfully on various substrates at room temperature. A wide interface layer exists between film and substrate, resulting in strong adhesion. Metal surface properties can be improved greatly by using this kind of treatment

Thulium heat source for high-endurance and high-energy density power systems

International Nuclear Information System (INIS)

Walter, C.E.; Kammeraad, J.E.; Van Konynenburg, R.; VanSant, J.H.

1991-05-01

We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5--50 kW th coupled with a power conversion efficiency of ∼30%, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered. 11 refs., 7 figs., 4 tabs

Optical and Electrical Properties of the Different Magnetron Sputter Power 300°C Deposited -ZnO Thin Films and Applications in p-i-n -Si:H Thin-Film Solar Cells

Directory of Open Access Journals (Sweden)

Fang-Hsing Wang

2013-01-01

Full Text Available A compound of ZnO with 3 wt% Ga2O3 (ZnO : Ga2O3 = 97 : 3 in wt%, GZO was sintered at C as a target. The GZO thin films were deposited on glass using a radio frequency magnetron sputtering system at C by changing the deposition power from 50 W to 150 W. The effects of deposition power on the crystallization size, lattice constant (c, resistivity, carrier concentration, carrier mobility, and optical transmission rate of the GZO thin films were studied. The blue shift in the transmission spectrum of the GZO thin films was found to change with the variations of the carrier concentration because of the Burstein-Moss shifting effect. The variations in the optical band gap ( value of the GZO thin films were evaluated from the plots of , revealing that the measured value decreased with increasing deposition power. As compared with the results deposited at room temperature by Gong et al., (2010 the C deposited GZO thin films had apparent blue shift in the transmission spectrum and larger value. For the deposited GZO thin films, both the carrier concentration and mobility linearly decreased and the resistivity linearly increased with increasing deposition power. The prepared GZO thin films were also used as transparent electrodes to fabricate the amorphous silicon thin-film solar cells, and their properties were also measured.

Modeling, fabrication and high power optical characterization of plasmonic waveguides

DEFF Research Database (Denmark)

Lavrinenko, Andrei; Lysenko, Oleg

2015-01-01

This paper describes modeling, fabrication and high power optical characterization of thin gold films embedded in silicon dioxide. The propagation vector of surface plasmon polaritons has been calculated by the effective index method for the wavelength range of 750-1700 nm and film thickness of 15......, 30 and 45 nm. The fabrication process of such plasmonic waveguides with width in the range of 1-100 μm and their quality inspection are described. The results of optical characterization of plasmonic waveguides using a high power laser with the peak power wavelength 1064 nm show significant deviation...... from the linear propagation regime of surface plasmon polaritons at the average input power of 100 mW and above. Possible reasons for this deviation are heating of the waveguides and subsequent changes in the coupling and propagation losses....

Construction of sputtering system and preparation of high temperature superconducting thin films

International Nuclear Information System (INIS)

Kaynak, E.

2000-01-01

The preparation of high T c superconducting thin film is important both for the understanding of fundamental behaviours of these materials and for the investigations on the usefulness of technological applications. High quality thin films can be prepared by various kinds of techniques being used today. Among these, sputtering is the most preferred one. The primary aim of this work is the construction of a r. f. and c. magnetron sputtering system. For this goal, a magnetron sputtering system was designed and constructed having powers up to 500W (r.f.) and 1KW (d.c.) that enables to deposit thin films of various kinds of materials: metals, ceramics and magnetic materials. The temperature dependence of the electrical resistance of the films was investigated by using four-point probe method. The zero resistance and the transition with of the films were measured as 80-85 K, and 2-9 K, respectively. The A.C. susceptibility experiments were done by utilising the system that was designed and constructed. The applied field dependence of the real and imaginary components of the susceptibility that were measured between the 77-120 K temperature interval and at a fixed frequency was investigated

Transparent conducting Al-doped ZnO thin films prepared by magnetron sputtering with dc and rf powers applied in combination

International Nuclear Information System (INIS)

Minami, Tadatsugu; Ohtani, Yuusuke; Miyata, Toshihiro; Kuboi, Takeshi

2007-01-01

A newly developed Al-doped ZnO (AZO) thin-film magnetron-sputtering deposition technique that decreases resistivity, improves resistivity distribution, and produces high-rate depositions has been demonstrated by dc magnetron-sputtering depositions that incorporate rf power (dc+rf-MS), either with or without the introduction of H 2 gas into the deposition chamber. The dc+rf-MS preparations were carried out in a pure Ar or an Ar+H 2 (0%-2%) gas atmosphere at a pressure of 0.4 Pa by adding a rf component (13.56 MHz) to a constant dc power of 80 W. The deposition rate in a dc+rf-MS deposition incorporating a rf power of 150 W was approximately 62 nm/min, an increase from the approximately 35 nm/min observed in dc magnetron sputtering with a dc power of 80 W. A resistivity as low as 3x10 -4 Ω cm and an improved resistivity distribution could be obtained in AZO thin films deposited on substrates at a low temperature of 150 deg. C by dc+rf-MS with the introduction of hydrogen gas with a content of 1.5%. This article describes the effects of adding a rf power component (i.e., dc+rf-MS deposition) as well as introducing H 2 gas into dc magnetron-sputtering preparations of transparent conducting AZO thin films

The influence of RF power on the electrical properties of sputtered amorphous In—Ga—Zn—O thin films and devices

International Nuclear Information System (INIS)

Shi Junfei; Dong Chengyuan; Wu Jie; Chen Yuting; Zhan Runze; Dai Wenjun

2013-01-01

The influence of radio frequency (RF) power on the properties of magnetron sputtered amorphous indium gallium zinc oxide (a-IGZO) thin films and the related thin-film transistor (TFT) devices is investigated comprehensively. A series of a-IGZO thin films prepared with magnetron sputtering at various RF powers are examined. The results prove that the deposition rate sensitively depends on RF power. In addition, the carrier concentration increases from 0.91 × 10 19 to 2.15 × 10 19 cm −3 with the RF power rising from 40 to 80 W, which may account for the corresponding decrease in the resistivity of the a-IGZO thin films. No evident impacts of RF power are observed on the surface roughness, crystalline nature and stoichiometry of the a-IGZO samples. On the other hand, optical transmittance is apparently influenced by RF power where the extracted optical band-gap value increases from 3.48 to 3.56 eV with RF power varying from 40 to 80 W, as is supposed to result from the carrier-induced band-filling effect. The rise in RF power can also affect the performance of a-IGZO TFTs, in particular by increasing the field-effect mobility clearly, which is assumed to be due to the alteration of the extended states in a-IGZO thin films. (semiconductor devices)

Sputtered molybdenum thin films and the application in CIGS solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhou, D.; Zhu, H., E-mail: hongbing1982@hotmail.com; Liang, X.; Zhang, C.; Li, Z.; Xu, Y.; Chen, J.; Zhang, L.; Mai, Y., E-mail: yaohuamai@hbu.edu.cn

2016-01-30

Graphical abstract: - Highlights: • Mo thin films are prepared by magnetron sputtering. • The dynamic deposition rate increases with the increasing discharge power. • The surface structure of Mo films varies with discharge power and working pressure. • High efficiency CIGS thin film solar cell of 15.2% has been obtained. - Abstract: Molybdenum (Mo) thin films are prepared by magnetron sputtering with different discharge powers and working pressures for the application in Cu(In, Ga)Se{sub 2} (CIGS) thin film solar cells as back electrodes. Properties of these Mo thin films are systematically investigated. It is found that the dynamic deposition rate increases with the increasing discharge power while decreases with the increasing working pressure. The highest dynamic deposition rate of 15.1 nm m/min is achieved for the Mo thin film deposited at the discharge power of 1200 W and at the working pressure of 0.15 Pa. The achieved lowest resistivity of 3.7 × 10{sup −5} Ω cm is attributed to the large grains in the compact thin film. The discharge power and working pressure have great influence on the sputtered Mo thin films. High efficiency of 12.5% was achieved for the Cu(In, Ga)Se{sub 2} (CIGS) thin film solar cells with Mo electrodes prepared at 1200 W and low working pressures. By further optimizing material and device properties, the conversion efficiency has reached to 15.2%.

Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

Science.gov (United States)

An, Haiyan; Jiang, Ching-Long J.; Xiong, Yihan; Zhang, Qiang; Inyang, Aloysius; Felder, Jason; Lewin, Alexander; Roff, Robert; Heinemann, Stefan; Schmidt, Berthold; Treusch, Georg

2015-03-01

We have continuously optimized high fill factor bar and packaging design to increase power and efficiency for thin disc laser system pump application. On the other hand, low fill factor bars packaged on the same direct copper bonded (DCB) cooling platform are used to build multi-kilowatt direct diode laser systems. We have also optimized the single emitter designs for fiber laser pump applications. In this paper, we will give an overview of our recent advances in high power high brightness laser bars and single emitters for pumping and direct diode application. We will present 300W bar development results for our next generation thin disk laser pump source. We will also show recent improvements on slow axis beam quality of low fill factor bar and its application on performance improvement of 4-5 kW TruDiode laser system with BPP of 30 mm*mrad from a 600 μm fiber. Performance and reliability results of single emitter for multiemitter fiber laser pump source will be presented as well.

Diffusively cooled thin-sheath high-repetition-rate TEA and TEMA lasers

Science.gov (United States)

Yatsiv, Shaul; Gabay, Amnon; Sintov, Yoav

1993-05-01

Transverse electric atmospheric (TEA), or multi atmospheric (TEMA) lasers deliver intense short laser pulses of considerable energies. Recurrent high repetition rate pulse trains afford substantial average power levels. In a high rep-rate operation the gas flows across the cavity and is externally cooled to maintain a reasonably low temperature. The gas flow gear and heat exchanger are bulky and costly. In this work we present a repetitively pulsed TEA or TEMA laser that combines energy and peak power features in an individual pulse with the substantial average power levels of a pulse train in a thin layer of gas. Excess heat is disposed of, by conduction through the gas, to cooled enclosing walls. The gas does not flow. The method applies to vibrational transition molecular lasers in the infrared, where elevated temperatures are deleterious to the laser operation. The gist of the method draws on the law that heat conductivity in gases does not depend on their pressure. The fact lends unique operational flexibility and compactness, desirable for industrial and research purposes.

Development of wall thinning screening system and its application to a commercial nuclear power plant

International Nuclear Information System (INIS)

Ryu, Kyung Ha; Hwang, Il Soon; Kim, Ji Hyun

2013-01-01

Highlights: • Wall loss screening system (WalSS) has been developed based on ES-DCPD method. • Screening criteria was established based on the thinning of the actual shape that occur in the power plant. • With the criteria, the WalSS gives priority of the need for inspection. • This technique was successfully applied to commercial nuclear power plant. - Abstract: A new non-destructive evaluation (NDE) method has been developed for metal pipes for the detection wall thinning. The method has been showed to be suitable for applications to electric power generation plants where flow accelerated corrosion (FAC) of carbon steel piping is a significant cause of increased maintenance and plant personnel casualty. The wall thinning screening system (WalSS) was developed in two major phases. In the first phase, the equipotential switching direct current potential drop (ES-DCPD) method was developed for piping wall (Ryu et al., 2008a, 2010). In the second phase, in this paper, a quantitative detection criteria was developed. The relative ES-DCPD change of 3.8% has been defined as the screening criteria for wall thinning schematization. This criteria means that the component with measured ES-DCPD change greater than 3.8% is called for a more comprehensive examination. In the criteria development, all variables were taken into consideration based on commercial plant piping inspection data such as initial thickness distributions, wall thinning shape and nominal thickness. The developed WalSS based on ES-DCPD was applied to a moisture separator reheater (MSR) drain line of a commercial nuclear power plant (NPP) during a scheduled overhaul. The measured ES-DCPD change was 2.16%, which is lower than the ES-DCPD criteria, identifying the pipe having adequate wall thickness. This is confirmed by site thickness inspection using ultrasonic technique (UT)

III-V Ultra-Thin-Body InGaAs/InAs MOSFETs for Low Standby Power Logic Applications

Science.gov (United States)

Huang, Cheng-Ying

As device scaling continues to sub-10-nm regime, III-V InGaAs/InAs metal- oxide-semiconductor ?eld-e?ect transistors (MOSFETs) are promising candidates for replacing Si-based MOSFETs for future very-large-scale integration (VLSI) logic applications. III-V InGaAs materials have low electron effective mass and high electron velocity, allowing higher on-state current at lower VDD and reducing the switching power consumption. However, III-V InGaAs materials have a narrower band gap and higher permittivity, leading to large band-to-band tunneling (BTBT) leakage or gate-induced drain leakage (GIDL) at the drain end of the channel, and large subthreshold leakage due to worse electrostatic integrity. To utilize III-V MOSFETs in future logic circuits, III-V MOSFETs must have high on-state performance over Si MOSFETs as well as very low leakage current and low standby power consumption. In this dissertation, we will report InGaAs/InAs ultra-thin-body MOSFETs. Three techniques for reducing the leakage currents in InGaAs/InAs MOSFETs are reported as described below. 1) Wide band-gap barriers: We developed AlAs0.44Sb0.56 barriers lattice-match to InP by molecular beam epitaxy (MBE), and studied the electron transport in In0.53Ga0.47As/AlAs 0.44Sb0.56 heterostructures. The InGaAs channel MOSFETs using AlAs0.44Sb0.56 bottom barriers or p-doped In0.52 Al0.48As barriers were demonstrated, showing significant suppression on the back barrier leakage. 2) Ultra-thin channels: We investigated the electron transport in InGaAs and InAs ultra-thin quantum wells and ultra-thin body MOSFETs (t ch ~ 2-4 nm). For high performance logic, InAs channels enable higher on-state current, while for low power logic, InGaAs channels allow lower BTBT leakage current. 3) Source/Drain engineering: We developed raised InGaAs and recessed InP source/drain spacers. The raised InGaAs source/drain spacers improve electrostatics, reducing subthreshold leakage, and smooth the electric field near drain, reducing

Tank wall thinning -- Process and programs

International Nuclear Information System (INIS)

Greer, S.D.; McBrine, W.J.

1994-01-01

In-service thinning of tank walls has occurred in the power industry and can pose a significant risk to plant safety and dependability. Appropriate respect for the energy stored in a high-pressure drain tank warrants a careful consideration of this possibility and appropriate action in order to assure the adequate safety margins against leakage or rupture. Although it has not proven to be a widespread problem, several cases of wall thinning and at least one recent tank rupture has highlighted this issue in recent years, particularly in nuclear power plants. However, the problem is not new or unique to the nuclear power industry. Severe wall thinning in deaerator tanks has been frequently identified at fossil-fueled power plants. There are many mechanisms which can contribute to tank wall thinning. Considerations for a specific tank are dictated by the system operating conditions, tank geometry, and construction material. Thinning mechanisms which have been identified include: Erosion/Corrosion Impingement Erosion Cavitation Erosion General Corrosion Galvanic Corrosion Microbial-induced Corrosion of course there are many other possible types of material degradation, many of which are characterized by pitting and cracking. This paper specifically addresses wall thinning induced by Erosion/Corrosion (also called Flow-Accelerated Corrosion) and Impingement Erosion of tanks in a power plant steam cycle. Many of the considerations presented are applicable to other types of vessels, such as moisture separators and heat exchangers

A display module implemented by the fast high-temperatue response of carbon nanotube thin yarns.

Science.gov (United States)

Wei, Yang; Liu, Peng; Jiang, Kaili; Fan, Shoushan

2012-05-09

Suspending superaligned multiwalled carbon nanotube (MWCNT) films were processed into CNT thin yarns, about 1 μm in diameter, by laser cutting and an ethanol atomization bath treatment. The fast high-temperature response under a vacuum was revealed by monitoring the incandescent light with a photo diode. The thin yarns can be electrically heated up to 2170 K in 0.79 mS, and the succeeding cool-down time is 0.36 mS. The fast response is attributed to the ultrasmall mass of the independent single yarn, large radiation coefficient, and improved thermal conductance through the two cool ends. The millisecond response time makes it possible to use the visible hot thin yarns as light-emitting elements of an incandescent display. A fully sealed display with 16 × 16 matrix was successfully fabricated using screen-printed thick electrodes and CNT thin yarns. It can display rolling characters with a low power consumption. More applications can be further developed based on the addressable CNT thermal arrays.

High performance direct methanol fuel cell with thin electrolyte membrane

Science.gov (United States)

Wan, Nianfang

2017-06-01

A high performance direct methanol fuel cell is achieved with thin electrolyte membrane. 320 mW cm-2 of peak power density and over 260 mW cm-2 at 0.4 V are obtained when working at 90 °C with normal pressure air supply. It is revealed that the increased anode half-cell performance with temperature contributes primarily to the enhanced performance at elevated temperature. From the comparison of iR-compensated cathode potential of methanol/air with that of H2/air fuel cell, the impact of methanol crossover on cathode performance decreases with current density and becomes negligible at high current density. Current density is found to influence fuel efficiency and methanol crossover significantly from the measurement of fuel efficiency at different current density. At high current density, high fuel efficiency can be achieved even at high temperature, indicating decreased methanol crossover.

Highly coercive thin-film nanostructures

International Nuclear Information System (INIS)

Zhou, J.; Skomski, R.; Kashyap, A.; Sorge, K.D.; Sui, Y.; Daniil, M.; Gao, L.; Yan, M.L.; Liou, S.-H.; Kirby, R.D.; Sellmyer, D.J.

2005-01-01

The processing, structure, and magnetism of highly coercive Sm-Co and FePt thin-film nanostructures are investigated. The structures include 1:5 based Sm-Co-Cu-Ti magnets, particulate FePt:C thin films, and FePt nanotubes. As in other systems, the coercivity depends on texture and imperfections, but there are some additional features. A specific coercivity mechanism in particulate media is a discrete pinning mode intermediate between Stoner-Wohlfarth rotation and ordinary domain-wall pinning. This mechanism yields a coercivity maximum for intermediate intergranular exchange and explains the occurrence of coercivities of 5 T in particulate Sm-Co-Cu-Ti magnets

Metallic plates lens focalizing a high power microwave beam

International Nuclear Information System (INIS)

Rebuffi, L.

1987-08-01

A metallic grating composed of thin parallel plates opportunely spaced, permits to correct the phase of an incident high power microwave beam. In this work we show how it is possible to obtain a beam focalisation (lens), a beam deflection (prisma), or a variation in the polarization (polarizer) using parallel metallic plates. The main design parameters are here presented, in order to obtain the wanted phase modification keeping low the diffraction, the reflected power, the ohmic losses and avoiding breakdowns. Following the given criteria, a metallic plate lens has been realized to focalize the 200 KW, 100 msec 60 GHz beam used in the ECRH experiment on the TFR tokamak. The experimental beam concentration followed satisfactory the design requirements. In fact, the maximum intensity increased about twice the value without lens. In correspondence of this distance a reduction of the beam size of about 50% have been measured for the -3 dB radius. The lens supported high power tests without breakdowns or increase of the reflected power

High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Lisco, F., E-mail: F.Lisco@lboro.ac.uk [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Losurdo, M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy); Walls, J.M. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

2015-01-01

Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films.

High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

International Nuclear Information System (INIS)

Lisco, F.; Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G.; Losurdo, M.; Walls, J.M.

2015-01-01

Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films

High-Power Ion Thruster Technology

Science.gov (United States)

Beattie, J. R.; Matossian, J. N.

1996-01-01

Performance data are presented for the NASA/Hughes 30-cm-diam 'common' thruster operated over the power range from 600 W to 4.6 kW. At the 4.6-kW power level, the thruster produces 172 mN of thrust at a specific impulse of just under 4000 s. Xenon pressure and temperature measurements are presented for a 6.4-mm-diam hollow cathode operated at emission currents ranging from 5 to 30 A and flow rates of 4 sccm and 8 sccm. Highly reproducible results show that the cathode temperature is a linear function of emission current, ranging from approx. 1000 C to 1150 C over this same current range. Laser-induced fluorescence (LIF) measurements obtained from a 30-cm-diam thruster are presented, suggesting that LIF could be a valuable diagnostic for real-time assessment of accelerator-arid erosion. Calibration results of laminar-thin-film (LTF) erosion badges with bulk molybdenum are presented for 300-eV xenon, krypton, and argon sputtering ions. Facility-pressure effects on the charge-exchange ion current collected by 8-cm-diam and 30-cm-diam thrusters operated on xenon propellant are presented to show that accel current is nearly independent of facility pressure at low pressures, but increases rapidly under high-background-pressure conditions.

Fabrication of high quality Cu2SnS3 thin film solar cell with 1.12% power conversion efficiency obtain by low cost environment friendly sol-gel technique

Science.gov (United States)

Chaudhari, J. J.; Joshi, U. S.

2018-03-01

Cu2SnS3 (CTS) is an emerging ternery chalcogenide material with great potential application in thin film solar cells. We present here high quality Cu2SnS3 thin films using a facile spin coating method. The as deposited films of CTS were sulphurized in a graphite box using tubular furnace at 520 °C for 60 min at the rate of 2.83 °C min-1 in argon atmosphere. X-ray diffraction (XRD) and Raman spectroscopy studies confirm tetragonal phase and absence of any secondary phase in sulphurized CTS thin films. X-ray photoelectron spectroscopy (XPS) demonstrates that Cu and Sn are in +1 and +4 oxidation state respectively. Surface morphology of CTS films were analyzed by field emission scanning electron microscope and atomic force microscope (AFM), which revealed a smooth surface with roughness (RMS) of 6.32 nm for sulphurized CTS film. Hall measurements confirmed p-type conductivity with hole concentartion of sulphurized CTS thin film is of 6.5348 × 1020 cm-3. UV-vis spectra revealed a direct energy band gap varies from 1.45 eV to 1.01 eV for as-deposited and sulphurized CTS thin film respectively. Such band gap values are optimum for semiconductor material as an absorber layer of thin film solar cell. The CTS thin film solar cell had following structure: SLG/FTO/ZnO/CTS/Al with short circuit current density of (Jsc) of 11.6 mA cm-2, open circuit voltage (Voc) of 0.276 V, active area of 0.16 cm2, fill factor (FF) of 35% and power conversion efficiency of 1.12% under AM 1.5 (100 mW cm-2) illumination in simulated standard test conditions.

Nanomechanical Behavior of High Gas Barrier Multilayer Thin Films.

Science.gov (United States)

Humood, Mohammad; Chowdhury, Shahla; Song, Yixuan; Tzeng, Ping; Grunlan, Jaime C; Polycarpou, Andreas A

2016-05-04

Nanoindentation and nanoscratch experiments were performed on thin multilayer films manufactured using the layer-by-layer (LbL) assembly technique. These films are known to exhibit high gas barrier, but little is known about their durability, which is an important feature for various packaging applications (e.g., food and electronics). Films were prepared from bilayer and quadlayer sequences, with varying thickness and composition. In an effort to evaluate multilayer thin film surface and mechanical properties, and their resistance to failure and wear, a comprehensive range of experiments were conducted: low and high load indentation, low and high load scratch. Some of the thin films were found to have exceptional mechanical behavior and exhibit excellent scratch resistance. Specifically, nanobrick wall structures, comprising montmorillonite (MMT) clay and polyethylenimine (PEI) bilayers, are the most durable coatings. PEI/MMT films exhibit high hardness, large elastic modulus, high elastic recovery, low friction, low scratch depth, and a smooth surface. When combined with the low oxygen permeability and high optical transmission of these thin films, these excellent mechanical properties make them good candidates for hard coating surface-sensitive substrates, where polymers are required to sustain long-term surface aesthetics and quality.

High power impulse magnetron sputtering and its applications

Science.gov (United States)

Yan, YUAN; Lizhen, YANG; Zhongwei, LIU; Qiang, CHEN

2018-04-01

High power impulse magnetron sputtering (HiPIMS) has attracted a great deal of attention because the sputtered material is highly ionized during the coating process, which has been demonstrated to be advantageous for better quality coating. Therefore, the mechanism of the HiPIMS technique has recently been investigated. In this paper, the current knowledge of HiPIMS is described. We focus on the mechanical properties of the deposited thin film in the latest applications, including hard coatings, adhesion enhancement, tribological performance, and corrosion protection layers. A description of the electrical, optical, photocatalytic, and functional coating applications are presented. The prospects for HiPIMS are also discussed in this work.

Photovoltaic Power for Mars Exploration

Science.gov (United States)

Bailey, Sheila G.; Landis, Geoffrey A.

1997-01-01

Mars is a challenging environment for the use of solar power. The implications of the low temperatures and low light intensity, solar spectrum modified by dust and changing with time of day and year, indirect sunlight, dust storms, deposited dust, wind, and corrosive peroxide-rich soil are discussed with respect to potential photovoltaic power systems. The power systems addressed include a solar-powered rover vehicle and a human base. High transportation costs dictate high efficiency solar cells or alternatively, a 'thin film' solar cell deposited on a lightweight plastic or thin metal foil.

Thin Mirror Shaping Technology for High-Throughput X-ray Telescopes

Science.gov (United States)

Schattenburg, Mark

This proposal is submitted to the NASA Research Opportunities in Space and Earth Sciences program (ROSES-2012) in response to NASA Research Announcement NNH12ZDA001N- APRA. It is targeted to the Astronomy and Astrophysics Research and Analysis (APRA) program element under the Supporting Technology category. Powerful x-ray telescope mirrors are critical components of a raft of small-to-large mission concepts under consideration by NASA. The science questions addressed by these missions have certainly never been more compelling and the need to fulfill NASA s core missions of exploring the universe and strengthening our nation s technology base has never been greater. Unfortunately, budgetary constraints are driving NASA to consider the cost/benefit and risk factors of new missions more carefully than ever. New technology for producing x-ray telescopes with increased resolution and collecting area, while holding down cost, are key to meeting these goals and sustaining a thriving high-energy astrophysics enterprise in the US. We propose to develop advanced technology which will lead to thin-shell x-ray telescope mirrors rivaling the Chandra x-ray telescope in spatial resolution but with 10-100X larger area all at significantly reduced weight, risk and cost. The proposed effort builds on previous research at MIT and complements NASA-supported research at other institutions. We are currently pursuing two thin-mirror technology development tracks which we propose to extend and accelerate with NASA support. The first research track utilizes rapidly-maturing thermal glass slumping technology which uses porous ceramic air-bearing mandrels to shape glass mirrors without touching, thus avoiding surface-induced mid-range spatial frequency ripples. A second research track seeks to remove any remaining mid- to long-range errors in mirrors by using scanning ion-beam implant to impart small, highly deterministic and very stable amounts of stress into thin glass, utilizing local

New concept for a high-power beam dump

International Nuclear Information System (INIS)

Moir, R.W.; Taylor, C.E.

1980-01-01

A new concept for a dump for the ion and neutral beams used in the controlled nuclear fusion program uses thin sheets of a refractory metal such as tungsten formed into troughs having semi-circular cross sections. High-velocity water flowing circumferentially removes heat by subcooled nucleate boiling. Possible advantages are modular construction, lower water-pumping power, and a lower pressure drop than in conventional beam dumps. An example design calculation is shown for a dump capable of absorbing an incident flux of 10 kW/cm 2

Experimental High Speed Milling of the Selected Thin-Walled Component

Directory of Open Access Journals (Sweden)

Jozef Zajac

2017-11-01

Full Text Available In a technical practice, it is possible to meet thin-walled parts more and more often. These parts are most commonly used in the automotive industry or aircraft industry to reduce the weight of different design part of cars or aircraft. Presented article is focused on experimental high speed milling of selected thin-walled component. The introduction of this article presents description of high speed machining and specification of thin – walled parts. The experiments were carried out using a CNC machine Pinnacle VMC 650S and C45 material - plain carbon steel for automotive components and mechanical engineering. In the last part of the article, described are the arrangements to reduction of deformation of thin-walled component during the experimental high speed milling.

Thin Flexible IMM Solar Array, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Thin, flexible, and highly efficient solar arrays are needed that package compactly for launch and deploy into large, structurally stable high power generators....

Potential of high-average-power solid state lasers

International Nuclear Information System (INIS)

Emmett, J.L.; Krupke, W.F.; Sooy, W.R.

1984-01-01

We discuss the possibility of extending solid state laser technology to high average power and of improving the efficiency of such lasers sufficiently to make them reasonable candidates for a number of demanding applications. A variety of new design concepts, materials, and techniques have emerged over the past decade that, collectively, suggest that the traditional technical limitations on power (a few hundred watts or less) and efficiency (less than 1%) can be removed. The core idea is configuring the laser medium in relatively thin, large-area plates, rather than using the traditional low-aspect-ratio rods or blocks. This presents a large surface area for cooling, and assures that deposited heat is relatively close to a cooled surface. It also minimizes the laser volume distorted by edge effects. The feasibility of such configurations is supported by recent developments in materials, fabrication processes, and optical pumps. Two types of lasers can, in principle, utilize this sheet-like gain configuration in such a way that phase and gain profiles are uniformly sampled and, to first order, yield high-quality (undistorted) beams. The zig-zag laser does this with a single plate, and should be capable of power levels up to several kilowatts. The disk laser is designed around a large number of plates, and should be capable of scaling to arbitrarily high power levels

Atomic force microscopy indentation of fluorocarbon thin films fabricated by plasma enhanced chemical deposition at low radio frequency power

International Nuclear Information System (INIS)

Sirghi, L.; Ruiz, A.; Colpo, P.; Rossi, F.

2009-01-01

Atomic force microscopy (AFM) indentation technique is used for characterization of mechanical properties of fluorocarbon (CF x ) thin films obtained from C 4 F 8 gas by plasma enhanced chemical vapour deposition at low r.f. power (5-30 W) and d.c. bias potential (10-80 V). This particular deposition method renders films with good hydrophobic property and high plastic compliance. Commercially available AFM probes with stiff cantilevers (10-20 N/m) and silicon sharpened tips (tip radius < 10 nm) are used for indentations and imaging of the resulted indentation imprints. Force depth curves and imprint characteristics are used for determination of film hardness, elasticity modulus and plasticity index. The measurements show that the decrease of the discharge power results in deposition of films with decreased hardness and stiffness and increased plasticity index. Nanolithography based on AFM indentation is demonstrated on thin films (thickness of 40 nm) with good plastic compliance.

Future Power Production by LENR with Thin-Film Electrodes

Science.gov (United States)

Miley, George H.; Hora, Heinz; Lipson, Andrei; Luo, Nie; Shrestha, P. Joshi

2007-03-01

PdD cluster reaction theory was recently proposed to explain a wide range of Low energy Nuclear Reaction (LENR) experiments. If understood and optimized, cluster reactions could lead to a revolutionary new power source of nuclear energy. The route is two-fold. First, the excess heat must be obtained reproducibly and over extended run times. Second, the percentage of excess must be significantly (order of magnitude or more) higher than the 20-50% typically today. The thin film methods described here have proven to be quite reproducible, e.g. providing excess heat of 20-30% in nine consecutive runs of several weeks each. However, mechanical separation of the films occurs over long runs due to the severe mechanical stresses created.. Techniques to overcome these problems are possible using graded bonding techniques similar to that used in high temperature solid oxide fuel cells. Thus the remaining key issue is to increase the excess heat. The cluster model provides import insight into this. G. H. Miley, H. Hora, et al., 233rd Amer Chem Soc Meeting, Chicago, IL, March 25-29, 2007.

High efficiency copper indium gallium diselenide (CIGS) thin film solar cells

Science.gov (United States)

Rajanikant, Ray Jayminkumar

The generation of electrical current from the solar radiation is known as the photovoltaic effect. Solar cell, also known as photovoltaic (PV) cell, is a device that works on the principle of photovoltaic effect, and is widely used for the generation of electricity. Thin film polycrystalline solar cells based on copper indium gallium diselenide (CIGS) are admirable candidates for clean energy production with competitive prices in the near future. CIGS based polycrystalline thin film solar cells with efficiencies of 20.3 % and excellent temperature stability have already been reported at the laboratory level. The present study discusses about the fabrication of CIGS solar cell. Before the fabrication part of CIGS solar cell, a numerical simulation is carried out using One-Dimensional Analysis of Microelectronic and Photonic Structures (AMPS-ID) for understanding the physics of a solar cell device, so that an optimal structure is analyzed. In the fabrication part of CIGS solar cell, Molybdenum (Mo) thin film, which acts as a 'low' resistance metallic back contact, is deposited by RF magnetron sputtering on organically cleaned soda lime glass substrate. The major advantages for using Mo are high temperature, (greater than 600 °C), stability and inertness to CIGS layer (i.e., no diffusion of CIGS into Mo). Mo thin film is deposited at room temperature (RT) by varying the RF power and the working pressure. The Mo thin films deposited with 100 W RF power and 1 mTorr working pressure show a reflectivity of above average 50 % and the low sheet resistance of about 1 O/□. The p-type CIGS layer is deposited on Mo. Before making thin films of CIGS, a powder of CIGS material is synthesized using melt-quenching method. Thin films of CIGS are prepared by a single-stage flash evaporation process on glass substrates, initially, for optimization of deposition parameters and than on Mo coated glass substrates for device fabrication. CIGS thin film is deposited at 250 °C at a

Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

Energy Technology Data Exchange (ETDEWEB)

Manaa, C., E-mail: chadlia.el.manaa@gmail.com [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Kouki, F. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Durand-Drouhin, O. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Bouchriha, H. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); and others

2014-06-02

We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method.

Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

International Nuclear Information System (INIS)

Manaa, C.; Lejeune, M.; Kouki, F.; Durand-Drouhin, O.; Bouchriha, H.

2014-01-01

We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method

Thin-film piezoelectric-on-silicon resonators for high-frequency reference oscillator applications.

Science.gov (United States)

Abdolvand, Reza; Lavasani, Hossein M; Ho, Gavin K; Ayazi, Farrokh

2008-12-01

This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators. Low-motional-impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble reference oscillators and the performance characteristics of the oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is approximately 350 microW for an oscillator operating at approximately 106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/ degrees C) temperature coefficient of frequency is obtained for an 82-MHz oscillator.

Time-resolved investigation of dual high power impulse magnetron sputtering with closed magnetic field during deposition of Ti-Cu thin films

International Nuclear Information System (INIS)

Stranak, Vitezslav; Hippler, Rainer; Cada, Martin; Hubicka, Zdenek; Tichy, Milan

2010-01-01

Time-resolved comparative study of dual magnetron sputtering (dual-MS) and dual high power impulse magnetron sputtering (dual-HiPIMS) systems arranged with closed magnetic field is presented. The dual-MS system was operated with a repetition frequency 4.65 kHz (duty cycle ≅50%). The frequency during dual-HiPIMS is lower as well as its duty cycle (f=100 Hz, duty 1%). Different metallic targets (Ti, Cu) and different cathode voltages were applied to get required stoichiometry of Ti-Cu thin films. The plasma parameters of the interspace between magnetrons in the substrate position were investigated by time-resolved optical emission spectroscopy, Langmuir probe technique, and measurement of ion fluxes to the substrate. It is shown that plasma density as well as ion flux is higher about two orders of magnitude in dual-HiPIMS system. This fact is partially caused by low diffusion of ionized sputtered particles (Ti + ,Cu + ) which creates a preionized medium.

High-temperature fabrication of Ag(In,Ga)Se{sub 2} thin films for applications in solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xianfeng [International Center for Science and Engineering Programs, Waseda University, Tokyo (Japan); Yamada, Akira [Department of Physical Electronics, Tokyo Institute of Technology, Tokyo (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo (Japan); Kagami Memorial Research Institute for Materials Science, Waseda University, Tokyo (Japan)

2017-10-15

Molecular beam epitaxy was used to fabricate Ag(In,Ga)Se{sub 2} (AIGS) thin films. To improve the diffusion of Ag, high-temperature deposition and high-temperature annealing methods were applied to fabricate AIGS films. The as-grown AIGS thin films were then used to make AIGS solar cells. We found that grain size and crystallinity of AIGS films were considerably improved by increasing the deposition and annealing temperature. For high-temperature deposition, temperatures over 600 C led to decomposition of the AIGS film, desorption of In, and deterioration of its crystallinity. The most appropriate deposition temperature was 590 C and a solar cell with a power conversion efficiency of 4.1% was obtained. High-temperature annealing of the AIGS thin films showed improved crystallinity as annealing temperature was increased and film decomposition and In desorption were prevented. A solar cell based on this film showed the highest conversion efficiency of 6.4% when annealed at 600 C. When the annealing temperature was further increased to 610 C, the performance of the cell deteriorated due to loss of the out-of-plane Ga gradient. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers

Energy Technology Data Exchange (ETDEWEB)

Huang Zhanyun; Chen Min; Chen Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510275 (China); Pan Shirong, E-mail: stscdh@mail.sysu.edu.c [Artificial Heart Lab, the 1st Affiliate Hospital of Sun Yat-Sen University, Guangzhou 510080 (China)

2010-10-01

In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

Impact of the difference in power frequency on diamond-like carbon thin film coating over 3-dimensional objects

Energy Technology Data Exchange (ETDEWEB)

Nakaya, Masaki, E-mail: m-nakaya@kirin.co.jp [Packaging Technology Development Center, Technology Development Department, Kirin Brewery Co., Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-8682 (Japan); Shimizu, Mari [Packaging Technology Development Center, Technology Development Department, Kirin Brewery Co., Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-8682 (Japan); Uedono, Akira [Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

2014-08-01

With a type of capacitatively coupled plasma enhanced chemical vapor deposition (PECVD) technique, where two specially designed electrodes face to each other, the inner surface of hollow 3-dimensional objects such as poly(ethylene terephthalate) (PET) bottles can be coated with diamond-like carbon (DLC) thin film. DLC-coated PET bottles obtained with this technique have an enhanced gas barrier property, and therefore are applicable to industrial use such as for the extension of the shelf-life of contents sensitive to gas permeation. In this paper, the impact of power frequency ranging from 2.5 to 13.56 MHz was studied in order to research the behavior of plasma inside PET bottles and resultant properties. Different power frequency turned out to be influential on gas barrier property, the overall and distribution of tint, and adhesion between DLC and PET substrate. In addition, positron annihilation turned out to be powerful tool for the comparison of different coating conditions because it clarifies the homogeneity of DLC thin films through providing information on overall structure and thickness of them. These findings can be used for the optimization not only in the beverage PET bottle application, but also in other capacitatively coupled PECVD devices. - Highlights: • We demonstrated an effective methodology for the homogeneity of thin films. • We described the influence of power frequency on plasma and resultant thin film. • Diamond-like carbon coated on poly(ethylene terephthalate) bottles was used. • Different frequency provided homogenous thin films based on the above methodology. • For the industrial performance of the bottles, optimization was found at 6 MHz.

Impact of the difference in power frequency on diamond-like carbon thin film coating over 3-dimensional objects

International Nuclear Information System (INIS)

Nakaya, Masaki; Shimizu, Mari; Uedono, Akira

2014-01-01

With a type of capacitatively coupled plasma enhanced chemical vapor deposition (PECVD) technique, where two specially designed electrodes face to each other, the inner surface of hollow 3-dimensional objects such as poly(ethylene terephthalate) (PET) bottles can be coated with diamond-like carbon (DLC) thin film. DLC-coated PET bottles obtained with this technique have an enhanced gas barrier property, and therefore are applicable to industrial use such as for the extension of the shelf-life of contents sensitive to gas permeation. In this paper, the impact of power frequency ranging from 2.5 to 13.56 MHz was studied in order to research the behavior of plasma inside PET bottles and resultant properties. Different power frequency turned out to be influential on gas barrier property, the overall and distribution of tint, and adhesion between DLC and PET substrate. In addition, positron annihilation turned out to be powerful tool for the comparison of different coating conditions because it clarifies the homogeneity of DLC thin films through providing information on overall structure and thickness of them. These findings can be used for the optimization not only in the beverage PET bottle application, but also in other capacitatively coupled PECVD devices. - Highlights: • We demonstrated an effective methodology for the homogeneity of thin films. • We described the influence of power frequency on plasma and resultant thin film. • Diamond-like carbon coated on poly(ethylene terephthalate) bottles was used. • Different frequency provided homogenous thin films based on the above methodology. • For the industrial performance of the bottles, optimization was found at 6 MHz

Method for making thin carbon foam electrodes

Science.gov (United States)

Pekala, Richard W.; Mayer, Steven T.; Kaschmitter, James L.; Morrison, Robert L.

1999-01-01

A method for fabricating thin, flat carbon electrodes by infiltrating highly porous carbon papers, membranes, felts, metal fibers/powders, or fabrics with an appropriate carbon foam precursor material. The infiltrated carbon paper, for example, is then cured to form a gel-saturated carbon paper, which is subsequently dried and pyrolyzed to form a thin sheet of porous carbon. The material readily stays flat and flexible during curing and pyrolyzing to form thin sheets. Precursor materials include polyacrylonitrile (PAN), polymethylacrylonitrile (PMAN), resorcinol/formaldehyde, catechol/formaldehyde, phenol/formaldehyde, etc., or mixtures thereof. These thin films are ideal for use as high power and energy electrodes in batteries, capacitors, and fuel cells, and are potentially useful for capacitive deionization, filtration and catalysis.

Simultaneous ultra-long data retention and low power based on Ge10Sb90/SiO2 multilayer thin films

Science.gov (United States)

You, Haipeng; Hu, Yifeng; Zhu, Xiaoqin; Zou, Hua; Song, Sannian; Song, Zhitang

2018-02-01

In this article, Ge10Sb90/SiO2 multilayer thin films were prepared to improve thermal stability and data retention for phase change memory. Compared with Ge10Sb90 monolayer thin film, Ge10Sb90 (1 nm)/SiO2 (9 nm) multilayer thin film had higher crystallization temperature and resistance contrast between amorphous and crystalline states. Annealed Ge10Sb90 (1 nm)/SiO2 (9 nm) had uniform grain with the size of 15.71 nm. After annealing, the root-mean-square surface roughness for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film increased slightly from 0.45 to 0.53 nm. The amorphization time for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film (2.29 ns) is shorter than Ge2Sb2Te5 (3.56 ns). The threshold voltage of a cell based on Ge10Sb90 (1 nm)/SiO2 (9 nm) (3.57 V) was smaller than GST (4.18 V). The results indicated that Ge10Sb90/SiO2 was a promising phase change thin film with high thermal ability and low power consumption for phase change memory application.

High magnetic field properties of Fe-pnictide thin films

Energy Technology Data Exchange (ETDEWEB)

Kurth, Fritz

2015-11-20

The recent discovery of high-temperature superconductivity in Fe-based materials triggered worldwide efforts to investigate their fundamental properties. Despite a lot of similarities to cuprates and MgB{sub 2}, important differences like near isotropic behaviour in contrast to cuprates and the peculiar pairing symmetry of the order parameter (OP) have been reported. The OP symmetry of Fe-based superconductors (FBS) was theoretically predicted to be of so-called s± state prior to various experimental works. Still, most of the experimental results favour the s± scenario; however, definitive evidence has not yet been reported. Although no clear understanding of the superconducting mechanisms yet exists, potential applications such as high-field magnets and Josephson devices have been explored. Indeed, a lot of reports about FBS tapes, wires, and even SQUIDs have been published to this date. In this thesis, the feasibility of high-field magnet applications of FBS is addressed by studying their transport properties, involving doped BaFe{sub 2}As{sub 2} (Ba-122) and LnFeAs(O,F) [Ln=Sm and Nd]. Particularly, it is important to study physical properties in a sample form (i.e. thin films) that is close to the conditions found in applications. However, the realisation of epitaxial FBS thin films is not an easy undertaking. Recent success in growing epitaxial FBS thin films opens a new avenue to delve into transport critical current measurements. The information obtained through this research will be useful for exploring high-field magnet applications. This thesis consists of 7 chapters: Chapter 1 describes the motivation of this study, the basic background of superconductivity, and a brief summary of the thin film growth of FBS. Chapter 2 describes experimental methods employed in this study. Chapter 3 reports on the fabrication of Co-doped Ba-122 thin films on various substrates. Particular emphasis lies on the discovery of fluoride substrates to be beneficial for

Effects of viscosity on power and hand injection of iso-osmolar iodinated contrast media through thin catheters.

Science.gov (United States)

Zhang, James J; Hogstrom, Barry; Malinak, Jiri; Ikei, Nobuhiro

2016-05-01

It can be challenging to achieve adequate vessel opacification during percutaneous coronary interventions when using thin catheters, hand injection, and iso-osmolar contrast media (CM) such as iodixanol (Visipaque™). To explore these limitations and the possibility to overcome them with iosimenol, a novel CM. Three X-ray contrast media with different concentrations were used in this study. A series of in vitro experiments established the relationship between injection pressure and flow rate in angiography catheters under various conditions. The experiments were conducted with power and hand injections and included a double-blind evaluation of user perception. By using hand injection, it was generally not possible to reach a maximum injection pressure exceeding 50 psi. The time within which volunteers were able to complete the injections, the area under the pressure-time curve (AUC), and assessment of ease of injection all were in favor of iosimenol compared with iodixanol, especially when using the 4F thin catheter. Within the pressure ranges tested, the power injections demonstrated that the amount of iodine delivered at a fixed pressure was strongly related to viscosity but unrelated to iodine concentration. There are substantial limitations to the amount of iodine that can be delivered through thin catheters by hand injection when iso-osmolar CM with high viscosity is used. The only viable solution, besides increasing the injection pressure, is to use a CM with lower viscosity, since the cost of increasing the concentration, in terms of increased viscosity and consequent reduction in flow, is too high. Iosimenol, an iso-osmolar CM with lower viscosity than iodixanol might therefore be a better alternative when thinner catheters are preferred, especially when the radial artery is used as the access site. © The Foundation Acta Radiologica 2015.

Laser plasma generation of hydrogen-free diamond-like carbon thin films on Zr-2.5Nb CANDU pressure tube materials and silicon wafers with a pulsed high-power CO2 laser

International Nuclear Information System (INIS)

Ebrahim, N.A.; Mouris, J.F.; Hoffmann, C.R.J.; Davis, R.W.

1995-06-01

We report the first experiments on the laser plasma deposition of hydrogen-free, diamond-like carbon (DLC) films on Zr-2.5Nb CANDU pressure-tube materials and silicon substrates, using the short-pulse, high-power, CO 2 laser in the High-Power Laser Laboratory at Chalk River Laboratories. The films were (AFM). The thin films show the characteristic signature of DLC films in the Raman spectra obtained using a krypton-ion (Kr + ) laser. The Vickers ultra-low-load microhardness tests show hardness of the coated surface of approximately 7000 Kg force mm -2 , which is consistent with the hardness associated with DLC films. AFM examination of the film morphology shows diamond-like crystals distributed throughout the film, with film thicknesses of up to 0.5 μm generated with 50 laser pulses. With significantly more laser pulses, it is expected that very uniform diamond-like films would be produced. These experiments suggest that it should be possible to deposit hydrogen-free, diamond-like films of relevance to nuclear reactor components with a high-power and high-repetition-rate laser facility. (author). 7 refs., 2 tabs., 15 figs

High-temperature stability of thermoelectric Ca₃Co₄O₉ thin films

DEFF Research Database (Denmark)

Brinks, P.; Van Nong, Ngo; Pryds, Nini

2015-01-01

An enhanced thermal stability in thermoelectric Ca3Co4O9 thin films up to 550 °C in an oxygen rich environment was demonstrated by high-temperature electrical and X-ray diffraction measurements. In contrast to generally performed heating in helium gas, it is shown that an oxygen/helium mixture...... provides sufficient thermal contact, while preventing the previously disregarded formation of oxygen vacancies. Combining thermal cycling with electrical measurements proves to be a powerful tool to study the real intrinsic thermoelectric behaviour of oxide thin films at elevated temperatures. © 2015 AIP...

Highly Sensitive Bulk Silicon Chemical Sensors with Sub-5 nm Thin Charge Inversion Layers.

Science.gov (United States)

Fahad, Hossain M; Gupta, Niharika; Han, Rui; Desai, Sujay B; Javey, Ali

2018-03-27

There is an increasing demand for mass-producible, low-power gas sensors in a wide variety of industrial and consumer applications. Here, we report chemical-sensitive field-effect-transistors (CS-FETs) based on bulk silicon wafers, wherein an electrostatically confined sub-5 nm thin charge inversion layer is modulated by chemical exposure to achieve a high-sensitivity gas-sensing platform. Using hydrogen sensing as a "litmus" test, we demonstrate large sensor responses (>1000%) to 0.5% H 2 gas, with fast response (<60 s) and recovery times (<120 s) at room temperature and low power (<50 μW). On the basis of these performance metrics as well as standardized benchmarking, we show that bulk silicon CS-FETs offer similar or better sensing performance compared to emerging nanostructures semiconductors while providing a highly scalable and manufacturable platform.

In situ determination of the dynamic properties of thinly-layered rock to evaluate rock-structure interaction at a nuclear power plant site

International Nuclear Information System (INIS)

Johnson, William J.; Rizzo, Paul C.

1988-01-01

The presence of layers of weak sedimentary rock in a column of otherwise competent rock can significantly affect the seismic response of nuclear power plant structures due to rock-structure interaction effects. The determination of the dynamic properties of thinly-layered rock is, however, difficult. When borings are placed close enough to allow for a characterization of refracted waves, other potential problems such as the identification of clear P- and S-wave arrivals, extremely short duration of records, near-field waves, instrumental stability, and overall record resolution become magnified. Other problems such as cultural noise and signal amplitude can become critical when high resolution is required. Conventional storage oscilloscopes and seismographs are inadequate under these conditions, but modern digital recording systems with the application of stringent calibration and recording procedures can yield successful results. A case history of a high-precision cross-hole survey to a depth of 150 meters in thinly-bedded sedimentary rock at a nuclear power plant site is presented in order to illustrate the systems and procedures necessary to obtain successful results under adverse conditions. (author)

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

Potential for efficient frequency conversion at high average power using solid state nonlinear optical materials

International Nuclear Information System (INIS)

Eimerl, D.

1985-01-01

High-average-power frequency conversion using solid state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (>70%) of Nd:YAG at average powers approaching 100 KW is possible; and for doubling to the blue or ultraviolet regions, the average power may approach 1 MW. Configurations using segmented apertures permit essentially unlimited scaling of average power. High average power is achieved by configuring the nonlinear material as a set of thin plates with a large ratio of surface area to volume and by cooling the exposed surfaces with a flowing gas. The design and material fabrication of such a harmonic generator are well within current technology

Applications of high-temperature superconductors in power technology

International Nuclear Information System (INIS)

Hull, John R

2003-01-01

Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications

The effect of aeration and solar intensity power on photocatalytic degradation of textile industrial wastewater using TiO2 thin film

International Nuclear Information System (INIS)

Abu Kassim, N.F.; Ku Hamid, K.H.; Azizan, A.

2006-01-01

Solar photo catalytic degradation of the textile industry wastewater using TiO 2 thin films was studied. This experiment was performed to investigate the effect of aeration and solar intensity power on decreasing of Chemical Oxygen Demand (COD). A serpentine flow photo catalytic reactor was developed for this purpose. TiO 2 thin films photo catalyst supported on the stainless steel 304 substrates were prepared using sol-gel dip coating method. The results of thin films were characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffractometer (XRD). XRD result showed that the prepared thin films gave the anatase crystallite formation whilst SEM demonstrated the macro pores were formed. Finally, the aeration and solar intensity power factors are considered to be responsible for the photo catalytic degradation. (Author)

Analysis of Pipe Wall-thinning Caused by Water Chemistry Change in Secondary System of Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Yun, Hun; Hwang, Kyeongmo [KEPCO E and C, Gimcheon (Korea, Republic of); Moon, Seung-Jae [Hanyang University, Seoul (Korea, Republic of)

2015-12-15

Pipe wall-thinning by flow-accelerated corrosion (FAC) is a significant and costly damage of secondary system piping in nuclear power plants (NPPs). All NPPs have their management programs to ensure pipe integrity from wall-thinning. This study analyzed the pipe wall-thinning caused by changing the amine, which is used for adjusting the water chemistry in the secondary system of NPPs. The pH change was analyzed according to the addition of amine. Then, the wear rate calculated in two different amines was compared at the steam cycle in NPPs. As a result, increasing the pH at operating temperature (Hot pH) can reduce the rate of FAC damage significantly. Wall-thinning is affected by amine characteristics depending on temperature and quality of water.

SiC nanofibers grown by high power microwave plasma chemical vapor deposition

International Nuclear Information System (INIS)

Honda, Shin-ichi; Baek, Yang-Gyu; Ikuno, Takashi; Kohara, Hidekazu; Katayama, Mitsuhiro; Oura, Kenjiro; Hirao, Takashi

2003-01-01

Silicon carbide (SiC) nanofibers have been synthesized on Si substrates covered by Ni thin films using high power microwave chemical vapor deposition (CVD). Characterization using transmission electron microscopy (TEM) combined with electron energy-dispersive X-ray spectroscopy (EDX) revealed that the resultant fibrous nanostructures were assigned to β-SiC with high crystallinity. The formation of SiC nanofibers can be explained by the vapor liquid solid (VLS) mechanism in which precipitation of SiC occurs from the supersaturated Ni nanoparticle containing Si and C

Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

Science.gov (United States)

Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

2012-10-01

Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity

KAUST Repository

Leung, Siu

2018-01-10

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3 NH3 PBI3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH3 NH3 PBI3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 1013 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW-1 cm-2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications.

High-intensity, thin-target He-jet production source

International Nuclear Information System (INIS)

Bai, Y.; Vieira, D.J.; Wouters, J.M.; Butler, G.W.; Rosenauer, Dk; Loebner, K.E.G.; Lind, V.G.; Phillips, D.R.

1996-01-01

A thin-target He-jet system suited to the production and rapid transport of non-volatile radioactive species has been successfully operated with proton beam intensities of up to 700 μA. The system consists of a water-cooled, thin-target chamber, capillary gas transport system, moving tape/Ge detection system, and an aerosol generator/gas recirculator. The yields for a wide variety of uranium fission and deep spallation products have been measured and robust operation of the system demonstrated for several weeks. He-jet transport and collection efficiencies ranged between 15 and 25% with collection rates of 10 7 to 10 8 atoms/sec/isotope. The high-intensity, thin-target He-jet approach represents a robust production source for nonvolatile radioactive heavy ion beams

High efficiency thin-film solar cells

Energy Technology Data Exchange (ETDEWEB)

Schock, Hans-Werner [Helmholtz Zentrum Berlin (Germany). Solar Energy

2012-11-01

Production of photovoltaics is growing worldwide on a gigawatt scale. Among the thin film technologies, Cu(In,Ga)S,Se{sub 2} (CIS or CIGS) based solar cells have been the focus of more and more attention. This paper aims to analyze the success of CIGS based solar cells and the potential of this technology for future photovoltaics large-scale production. Specific material properties make CIS unique and allow the preparation of the material with a wide range of processing options. The huge potential lies in the possibility to take advantage of modern thin film processing equipment and combine it with very high efficiencies beyond 20% already achieved on the laboratory scale. A sustainable development of this technology could be realized by modifying the materials and replacing indium by abundant elements. (orig.)

Multifunctional Architectures Constructing of PANI Nanoneedle Arrays on MoS2 Thin Nanosheets for High-Energy Supercapacitors.

Science.gov (United States)

Zhu, Jixin; Sun, Wenping; Yang, Dan; Zhang, Yu; Hoon, Hng Huey; Zhang, Hua; Yan, Qingyu

2015-09-02

Multifunctional MoS2 @PANI (polyaniline) pseudo-supercapacitor electrodes consisting of MoS2 thin nanosheets and PANI nanoarrays are fabricated via a large-scale approach. The superior capacitance retention is retained up to 91% after 4000 cycles and a high energy density of 106 Wh kg(-1) is delivered at a power density of 106 kW kg(-1) . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

Science.gov (United States)

Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

2018-04-01

In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

Effect of sputtering power on structure, adhesion strength and corrosion resistance of nitrogen doped diamond-like carbon thin films.

Science.gov (United States)

Khun, N W; Liu, E

2011-06-01

Nitrogen doped diamond-like carbon (DLC:N) thin films were deposited on highly conductive p-Si substrates using a DC magnetron sputtering deposition system. The DLC:N films were characterized using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM), contact angle measurement and micro-scratch test. The XPS and Raman results indicated that the sputtering power significantly influenced the properties of the films in terms of bonding configuration in the films. The corrosion performance of the DLC:N films was investigated in a 0.6 M NaCl solution by means of potentiodynamic polarization testing. It was found that the corrosion performance of the films could be enhanced by higher sputtering powers.

High resolving power spectrometer for beam analysis

International Nuclear Information System (INIS)

Moshammer, H.W.; Spencer, J.E.

1992-03-01

We describe a system designed to analyze the high energy, closely spaced bunches from individual RF pulses. Neither a large solid angle nor momentum range is required so this allows characteristics that appear useful for other applications such as ion beam lithography. The spectrometer is a compact, double-focusing QBQ design whose symmetry allows the Quads to range between F or D with a correspondingly large range of magnifications, dispersion and resolving power. This flexibility insures the possibility of spatially separating all of the bunches along the focal plane with minimal transverse kicks and bending angle for differing input conditions. The symmetry of the system allows a simple geometric interpretationof the resolving power in terms of thin lenses and ray optics. We discuss the optics and the hardware that is proposed to measure emittance, energy, energy spread and bunch length for each bunch in an RF pulse train for small bunch separations. We also discuss how to use such measurements for feedback and feedforward control of these bunch characteristics as well as maintain their stability. 2 refs

Thin Film Packaging Solutions for High Efficiency OLED Lighting Products

Energy Technology Data Exchange (ETDEWEB)

None

2008-06-30

The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology

Wavy channel Thin Film Transistor for area efficient, high performance and low power applications

KAUST Repository

Hanna, Amir; Sevilla, Galo T.; Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

2014-01-01

We report a new Thin Film Transistor (TFT) architecture that allows expansion of the device width using wavy (continuous without separation) fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor

Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients

KAUST Repository

Yip, Ngai Yin

2011-05-15

Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. This work presents the fabrication of thin-film composite membranes customized for high performance in pressure retarded osmosis. We also present the development of a theoretical model to predict the water flux in pressure retarded osmosis, from which we can predict the power density that can be achieved by a membrane. The model is the first to incorporate external concentration polarization, a performance limiting phenomenon that becomes significant for high-performance membranes. The fabricated membranes consist of a selective polyamide layer formed by interfacial polymerization on top of a polysulfone support layer made by phase separation. The highly porous support layer (structural parameter S = 349 μm), which minimizes internal concentration polarization, allows the transport properties of the active layer to be customized to enhance PRO performance. It is shown that a hand-cast membrane that balances permeability and selectivity (A = 5.81 L m-2 h-1 bar-1, B = 0.88 L m-2 h-1) is projected to achieve the highest potential peak power density of 10.0 W/m2 for a river water feed solution and seawater draw solution. The outstanding performance of this membrane is attributed to the high water permeability of the active layer, coupled with a moderate salt permeability and the ability of the support layer to suppress the undesirable accumulation of leaked salt in the porous support. Membranes with greater selectivity (i.e., lower salt permeability, B = 0.16 L m-2 h-1) suffered from a lower water permeability (A = 1.74 L m-2 h-1 bar-1) and would yield a lower peak power density of 6.1 W/m2, while membranes with a higher permeability and lower selectivity (A = 7.55 L m-2 h-1 bar-1, B = 5.45 L m-2 h-1) performed poorly due to severe reverse salt permeation, resulting in a similar projected peak power density of 6.1 W/m2. © 2011 American Chemical Society.

Ultrathin Coaxial Fiber Supercapacitors Achieving High Energy and Power Densities.

Science.gov (United States)

Shen, Caiwei; Xie, Yingxi; Sanghadasa, Mohan; Tang, Yong; Lu, Longsheng; Lin, Liwei

2017-11-15

Fiber-based supercapacitors have attracted significant interests because of their potential applications in wearable electronics. Although much progress has been made in recent years, the energy and power densities, mechanical strength, and flexibility of such devices are still in need of improvement for practical applications. Here, we demonstrate an ultrathin microcoaxial fiber supercapacitor (μCFSC) with high energy and power densities (2.7 mW h/cm 3 and 13 W/cm 3 ), as well as excellent mechanical properties. The prototype with the smallest reported overall diameter (∼13 μm) is fabricated by successive coating of functional layers onto a single micro-carbon-fiber via a scalable process. Combining the simulation results via the electrochemical model, we attribute the high performance to the well-controlled thin coatings that make full use of the electrode materials and minimize the ion transport path between electrodes. Moreover, the μCFSC features high bending flexibility and large tensile strength (more than 1 GPa), which make it promising as a building block for various flexible energy storage applications.

High energy high repetition-rate thin-disk amplifier for OPCPA pumping

Energy Technology Data Exchange (ETDEWEB)

Schulz, Michael

2013-08-15

The development of a pump laser system for a high power and high repetition rate optical parametric chirped-pulse amplification (OPCPA) is presented in this thesis. The OPCPA system requires pump pulse energies in the range of tens of millijoules at high repetition rates with sub-picosecond pulse durations. This can be achieved to some extend with Innoslab amplifier technology. However, scaling to higher pulse energies at high repetition rates may be problematic. With the thin-disk amplifier presented in this thesis, output energies of 140 mJ at 100 kHz repetition rate could be achieved in burst-mode operation, which is a world record for this type of laser amplifier. Due to its material and spectral properties, ytterbium doped YAG (Yb:YAG) is used as a gain medium for the high power amplifier stages. The low quantum defect and the comparatively large emission bandwidth makes this material the choice for high power operation and sub-picosecond compressed pulse durations. The output beam profile as well as the shape of the output bursts is ideal to pump an OPCPA system. An OPCPA output energy in the millijoule range with repetition rates of 100 kHz to 1 MHz is needed to generate seed pulses for the FEL and for the application as pump-probe laser at the FEL facility. Since the development of this laser system needs to meet requirements set by the Free-Electron Laser in Hamburg (FLASH), the amplifier is conceived for burst-mode operation. The main requirement is a high intra-burst pulse repetition rate of more than 100 kHz and a uniform pulse train (burst) with equal properties for every pulse. The burst-mode is an operation mode where the laser never reaches a lasing equilibrium, which means that the behavior of the amplifier is similar to a switch-on of the laser system for every burst. This makes the development of the amplifier system difficult. Therefore, an analytical model has been developed to study the amplification process during the burst. This includes the

High energy high repetition-rate thin-disk amplifier for OPCPA pumping

International Nuclear Information System (INIS)

Schulz, Michael

2013-08-01

The development of a pump laser system for a high power and high repetition rate optical parametric chirped-pulse amplification (OPCPA) is presented in this thesis. The OPCPA system requires pump pulse energies in the range of tens of millijoules at high repetition rates with sub-picosecond pulse durations. This can be achieved to some extend with Innoslab amplifier technology. However, scaling to higher pulse energies at high repetition rates may be problematic. With the thin-disk amplifier presented in this thesis, output energies of 140 mJ at 100 kHz repetition rate could be achieved in burst-mode operation, which is a world record for this type of laser amplifier. Due to its material and spectral properties, ytterbium doped YAG (Yb:YAG) is used as a gain medium for the high power amplifier stages. The low quantum defect and the comparatively large emission bandwidth makes this material the choice for high power operation and sub-picosecond compressed pulse durations. The output beam profile as well as the shape of the output bursts is ideal to pump an OPCPA system. An OPCPA output energy in the millijoule range with repetition rates of 100 kHz to 1 MHz is needed to generate seed pulses for the FEL and for the application as pump-probe laser at the FEL facility. Since the development of this laser system needs to meet requirements set by the Free-Electron Laser in Hamburg (FLASH), the amplifier is conceived for burst-mode operation. The main requirement is a high intra-burst pulse repetition rate of more than 100 kHz and a uniform pulse train (burst) with equal properties for every pulse. The burst-mode is an operation mode where the laser never reaches a lasing equilibrium, which means that the behavior of the amplifier is similar to a switch-on of the laser system for every burst. This makes the development of the amplifier system difficult. Therefore, an analytical model has been developed to study the amplification process during the burst. This includes the

The power flow angle of acoustic waves in thin piezoelectric plates.

Science.gov (United States)

Kuznetsova, Iren E; Zaitsev, Boris D; Teplykh, Andrei A; Joshi, Shrinivas G; Kuznetsova, Anastasia S

2008-09-01

The curves of slowness and power flow angle (PFA) of quasi-antisymmetric (A(0)) and quasi-symmetric (S(0)) Lamb waves as well as quasi-shear-horizontal (SH(0)) acoustic waves in thin plates of lithium niobate and potassium niobate of X-,Y-, and Z-cuts for various propagation directions and the influence of electrical shorting of one plate surface on these curves and PFA have been theoretically investigated. It has been found that the group velocity of such waves does not coincide with the phase velocity for the most directions of propagation. It has been also shown that S(0) and SH(0) wave are characterized by record high values of PFA and its change due to electrical shorting of the plate surface in comparison with surface and bulk acoustic waves in the same material. The most interesting results have been verified by experiment. As a whole, the results obtained may be useful for development of various devices for signal processing, for example, electrically controlled acoustic switchers.

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity.

Science.gov (United States)

Leung, Siu-Fung; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K S; Alshareef, Husam N; Wang, Zhong Lin; He, Jr-Hau

2018-02-01

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH 3 NH 3 PBI 3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH 3 NH 3 PBI 3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 10 13 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW -1 cm -2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

Energy Technology Data Exchange (ETDEWEB)

Ma, Chunrui [Univ. of Texas, San Antonio, TX (United States); Enriquez, Erik [Univ. of Texas, San Antonio, TX (United States); Wang, Haibing [Univ. of Texas, San Antonio, TX (United States); Xu, Xing [Univ. of Texas, San Antonio, TX (United States); Bao, Shangyong [Univ. of Texas, San Antonio, TX (United States); Collins, Gregory [Univ. of Texas, San Antonio, TX (United States)

2013-08-13

The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo₂O_5+d (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

Magnetic properties and high frequency characteristics of FeCoN thin films

Directory of Open Access Journals (Sweden)

Tae-Jong Hwang

2016-05-01

Full Text Available (Fe65Co35N soft magnetic thin films were prepared by reactive RF magnetron sputtering with the sputtering power of 100 W on thermally oxidized Si substrate in various nitrogen partial pressures (PN2. A strong uniaxial in-plane magnetic anisotropy with the easy-axis coercive field as low as 1∼2 Oe was observed in films grown at PN2 in the range from 3.3% to 5.5%. The saturation magnetizations for those films were about 20 KG. Outside this range, almost isotropic magnetization curves were observed. Vector network analyzer and grounded coplanar waveguide were used to measure the ferromagnetic resonance (FMR signals up to 25 GHz. The FMR signals were detected only in anisotropic films and their FMR frequencies were well fit to the Kittel formula. The obtained g-values and damping parameters at magnetic fields >20 kOe for films grown at PN2 of 3.3%, 4.8% and 5.5% were 1.96, 1.86, 1.92 and 0.0055, 0.0047, 0.0046, respectively. This low damping factor qualifies FeCoN thin films for high-frequency applications.

Development of Wall-Thinning Evaluation Procedure for Nuclear Power Plant Piping—Part 1: Quantification of Thickness Measurement Deviation

Directory of Open Access Journals (Sweden)

Hun Yun

2016-06-01

Full Text Available Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs. Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

High-quality EuO thin films the easy way via topotactic transformation

Science.gov (United States)

Mairoser, Thomas; Mundy, Julia A.; Melville, Alexander; Hodash, Daniel; Cueva, Paul; Held, Rainer; Glavic, Artur; Schubert, Jürgen; Muller, David A.; Schlom, Darrell G.; Schmehl, Andreas

2015-07-01

Epitaxy is widely employed to create highly oriented crystalline films. A less appreciated, but nonetheless powerful means of creating such films is via topotactic transformation, in which a chemical reaction transforms a single crystal of one phase into a single crystal of a different phase, which inherits its orientation from the original crystal. Topotactic reactions may be applied to epitactic films to substitute, add or remove ions to yield epitactic films of different phases. Here we exploit a topotactic reduction reaction to provide a non-ultra-high vacuum (UHV) means of growing highly oriented single crystalline thin films of the easily over-oxidized half-metallic semiconductor europium monoxide (EuO) with a perfection rivalling that of the best films of the same material grown by molecular-beam epitaxy or UHV pulsed-laser deposition. As the technique only requires high-vacuum deposition equipment, it has the potential to drastically improve the accessibility of high-quality single crystalline films of EuO as well as other difficult-to-synthesize compounds.

High Performance Thin-Film Composite Forward Osmosis Membrane

KAUST Repository

Yip, Ngai Yin; Tiraferri, Alberto; Phillip, William A.; Schiffman, Jessica D.; Elimelech, Menachem

2010-01-01

obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed

Graphene-based in-plane micro-supercapacitors with high power and energy densities.

Science.gov (United States)

Wu, Zhong-Shuai; Parvez, Khaled; Feng, Xinliang; Müllen, Klaus

2013-01-01

Micro-supercapacitors are important on-chip micro-power sources for miniaturized electronic devices. Although the performance of micro-supercapacitors has been significantly advanced by fabricating nanostructured materials, developing thin-film manufacture technologies and device architectures, their power or energy densities remain far from those of electrolytic capacitors or lithium thin-film batteries. Here we demonstrate graphene-based in-plane interdigital micro-supercapacitors on arbitrary substrates. The resulting micro-supercapacitors deliver an area capacitance of 80.7 μF cm⁻² and a stack capacitance of 17.9 F cm⁻³. Further, they show a power density of 495 W cm⁻³ that is higher than electrolytic capacitors, and an energy density of 2.5 mWh cm⁻³ that is comparable to lithium thin-film batteries, in association with superior cycling stability. Such microdevices allow for operations at ultrahigh rate up to 1,000 V s⁻¹, three orders of magnitude higher than that of conventional supercapacitors. Micro-supercapacitors with an in-plane geometry have great promise for numerous miniaturized or flexible electronic applications.

Graphene-based in-plane micro-supercapacitors with high power and energy densities

Science.gov (United States)

Wu, Zhong–Shuai; Parvez, Khaled; Feng, Xinliang; Müllen, Klaus

2013-01-01

Micro-supercapacitors are important on-chip micro-power sources for miniaturized electronic devices. Although the performance of micro-supercapacitors has been significantly advanced by fabricating nanostructured materials, developing thin-film manufacture technologies and device architectures, their power or energy densities remain far from those of electrolytic capacitors or lithium thin-film batteries. Here we demonstrate graphene-based in-plane interdigital micro-supercapacitors on arbitrary substrates. The resulting micro-supercapacitors deliver an area capacitance of 80.7 μF cm−2 and a stack capacitance of 17.9 F cm−3. Further, they show a power density of 495 W cm−3 that is higher than electrolytic capacitors, and an energy density of 2.5 mWh cm−3 that is comparable to lithium thin-film batteries, in association with superior cycling stability. Such microdevices allow for operations at ultrahigh rate up to 1,000 V s−1, three orders of magnitude higher than that of conventional supercapacitors. Micro-supercapacitors with an in-plane geometry have great promise for numerous miniaturized or flexible electronic applications. PMID:24042088

High performance, transparent a-IGZO TFTs on a flexible thin glass substrate

International Nuclear Information System (INIS)

Lee, Gwang Jun; Jang, Jae Eun; Kim, Joonwoo; Kim, Jung-Hye; Jeong, Soon Moon; Jeong, Jaewook

2014-01-01

We investigated electrical properties of transparent amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with amorphous indium zinc oxide (a-IZO) transparent electrodes on a flexble thin glass substrate. The TFTs show a high field-effect mobility, a good subthreshold slope and a high on/off ratio owing to the high temperature thermal annealing process which cannot be applied to typical transparent polymer-based flexible substrates. Bias stress instability tests applying tensile stress concurrently with the bending radius of up to 40 mm indicated that mechanically and electrically stable a-IGZO TFTs can be fabricated on the transparent thin glass substrate. (paper)

ON-POWER DETECTION OF PIPE WALL-THINNED DEFECTS USING IR THERMOGRAPHY IN NPPS

Directory of Open Access Journals (Sweden)

JU HYUN KIM

2014-04-01

Full Text Available Wall-thinned defects caused by accelerated corrosion due to fluid flow in the inner pipe appear in many structures of the secondary systems in nuclear power plants (NPPs and are a major factor in degrading the integrity of pipes. Wall-thinned defects need to be managed not only when the NPP is under maintenance but also when the NPP is in normal operation. To this end, a test technique was developed in this study to detect such wall-thinned defects based on the temperature difference on the surface of a hot pipe using infrared (IR thermography and a cooling device. Finite element analysis (FEA was conducted to examine the tendency and experimental conditions for the cooling experiment. Based on the FEA results, the equipment was configured before the cooling experiment was conducted. The IR camera was then used to detect defects in the inner pipe of the pipe specimen that had artificially induced defects. The IR thermography developed in this study is expected to help resolve the issues related to the limitations of non-destructive inspection techniques that are currently conducted for NPP secondary systems and is expected to be very useful on the NPPs site.

Changes of optical, dielectric, and structural properties of Si15Sb85 phase change memory thin films under different initializing laser power

International Nuclear Information System (INIS)

Huang Huan; Zhang Lei; Wang Yang; Han Xiaodong; Wu Yiqun; Zhang Ze; Gan Fuxi

2011-01-01

Research highlights: → We study the optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization. → The optical and dielectric constants, absorption coefficient of Si 15 Sb 85 change regularly with the increasing laser power. → The optical band gaps of Si 15 Sb 85 irradiated upon different power lasers were calculated. → HRTEM images of the samples were observed and the changes of optical and dielectric constants are determined by crystalline structures changes of the films. - Abstract: The optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization are studied by using spectroscopic ellipsometry and high-resolution transmission electron microscopy. The dependence of complex refractive index, dielectric functions, absorption coefficient, and optical band gap of the films on its crystallization extents formed by the different initialization laser power are analyzed in detail. The structural change from as-deposited amorphous phase to distorted rhombohedra-Sb-like crystalline structure with the increase of initialization laser power is clearly observed with sub-nanometer resolution. The optical and dielectric constants, the relationship between them, and the local atomic arrangements of this new phase change material can help explain the phase change mechanism and design the practical phase change memory devices.

High index glass thin film processing for photonics and photovoltaic (PV) applications

Science.gov (United States)

Ogbuu, Okechukwu Anthony

To favorably compete with fossil-fuel technology, the greatest challenge for thin film solar-cells is to improve efficiency and reduce material cost. Thickness scaling to thin film reduces material cost but affects the light absorption in the cells; therefore a concept that traps incident photons and increases its optical path length is needed to boost absorption in thin film solar cells. One approach is the integration of low symmetric gratings (LSG), using high index material, on either the front-side or backside of 30 um thin c-Si cells. In this study, Multicomponent TeO2--Bi2O 3--ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy. The results indicate that TBZ glass thin film is a suitable material for front side LSG material photovoltaic and photonics applications due to their amorphous nature, high refractive index (n > 2), broad band optical transparency window, low processing temperature. We developed a simple maskless method to pattern sputtered tellurite based glass thin films using unconventional agarose hydrogel mediated wet etching. Conventional wet etching process, while claiming low cost and high throughput, suffers from reproducibility and pattern fidelity issues due to the isotropic nature of wet chemical etching when applied to glasses and polymers. This method overcomes these challenges by using an agarose hydrogel stamp to mediate a conformal etching process. In our maskless method, agarose hydrogel stamps are patterned following a standard soft lithography and replica molding process from micropatterned masters and soaked in a chemical etchant. The micro-scale features on the stamp are

Radiation resistance of thin-film solar cells for space photovoltaic power

Science.gov (United States)

Woodyard, James R.; Landis, Geoffrey A.

1991-01-01

Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

Development of optical thin film technology for lasers and synchrotron radiation

International Nuclear Information System (INIS)

Apparao, K.V.S.R.; Bagchi, T.C.; Sahoo, N.K.

1985-01-01

Dielectric multilayer optical thin film devices play an important role not only in the working of lasers but also in different front line research activities using high power lasers and high intensity synchrotron radiation sources. Facilities are set up recently in the Spectroscopy Division to develop the optical thin film design and fabrication technologies indigeneously. Using the facilities thin film devices for different laser applications working in the wavelength range from 300 nm to 1064 nm were developed. Different technical aspects involved in the technology development are briefly described. (author)

High-pressure oxygenation of thin-wall YBCO single-domain samples

International Nuclear Information System (INIS)

Chaud, X; Savchuk, Y; Sergienko, N; Prikhna, T; Diko, P

2008-01-01

The oxygen annealing of ReBCO bulk material, necessary to achieve superconducting properties, usually induces micro- and macro-cracks. This leads to a crack-assisted oxygenation process that allows oxygenating large bulk samples faster than single crystals. But excellent superconducting properties are cancelled by the poor mechanical ones. More progressive oxygenation strategy has been shown to reduce drastically the oxygenation cracks. The problem then arises to keep a reasonable annealing time. The concept of bulk Y123 single-domain samples with thin-wall geometry has been introduced to bypass the inherent limitation due to a slow oxygen diffusion rate. But it is not enough. The use of a high oxygen pressure (16 MPa) enables to speed up further the process. It introduces a displacement in the equilibrium phase diagram towards higher temperatures, i.e., higher diffusion rates, to achieve a given oxygen content in the material. Remarkable results were obtained by applying such a high pressure oxygen annealing process on thin-wall single-domain samples. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6T vs 0.3T at 77K) using an annealing time twice shorter (about 3 days). The initial development was made on thin bars. The advantage of thin-wall geometry is that such an annealing can be applied directly to a much larger sample

High-coercivity FePt nanoparticle assemblies embedded in silica thin films

International Nuclear Information System (INIS)

Yan, Q; Purkayastha, A; Singh, A P; Li, H; Ramanath, G; Li, A; Ramanujan, R V

2009-01-01

The ability to process assemblies using thin film techniques in a scalable fashion would be a key to transmuting the assemblies into manufacturable devices. Here, we embed FePt nanoparticle assemblies into a silica thin film by sol-gel processing. Annealing the thin film composite at 650 deg. C transforms the chemically disordered fcc FePt phase into the fct phase, yielding magnetic coercivity values H c >630 mT. The positional order of the particles is retained due to the protection offered by the silica host. Such films with assemblies of high-coercivity magnetic particles are attractive for realizing new types of ultra-high-density data storage devices and magneto-composites.

Fiber facet gratings for high power fiber lasers

Science.gov (United States)

Vanek, Martin; Vanis, Jan; Baravets, Yauhen; Todorov, Filip; Ctyroky, Jiri; Honzatko, Pavel

2017-12-01

We numerically investigated the properties of diffraction gratings designated for fabrication on the facet of an optical fiber. The gratings are intended to be used in high-power fiber lasers as mirrors either with a low or high reflectivity. The modal reflectance of low reflectivity polarizing grating has a value close to 3% for TE mode while it is significantly suppressed for TM mode. Such a grating can be fabricated on laser output fiber facet. The polarizing grating with high modal reflectance is designed as a leaky-mode resonant diffraction grating. The grating can be etched in a thin layer of high index dielectric which is sputtered on fiber facet. We used refractive index of Ta2O5 for such a layer. We found that modal reflectance can be close to 0.95 for TE polarization and polarization extinction ratio achieves 18 dB. Rigorous coupled wave analysis was used for fast optimization of grating parameters while aperiodic rigorous coupled wave analysis, Fourier modal method and finite difference time domain method were compared and used to compute modal reflectance of designed gratings.

Harnessing the Sun with Thin Film Photovoltaics: Preprint

International Nuclear Information System (INIS)

Birkmire, R. W.; Kazmerski, L. L.

1999-01-01

Photovoltaic (PV) technologies have a substantial role in meeting electric power needs in the next century, especially with an expected competitive position compared to conventional power-generation and other renewable- energy technologies. Thin-film photovoltaic modules based on CdTe, CuInSe2 or Si can potentially be produced by economical, high-volume manufacturing techniques, dramatically reducing component cost. However, the translation of laboratory thin-film technologies to first-time, large-scale manufacturing has been much more difficult than expected. This is due to the complexity of the processes involved for making large-area PV modules at high rates and with high yields, and compounded by the lack of a fundamental scientific and engineering base required to properly engineer and operate manufacturing equipment. In this paper, we discuss the need to develop diagnostics tools and associated predictive models that quantitatively assess processing conditions and pro duct properties. Incorporation of the diagnostic sensors into both laboratory reactors and manufacturing facilities will (1) underpin the development of solar cells with improved efficiency, and (2) accelerate the scale-up process through intelligent process-control schemes. ''Next-generation'' high-performance (e.g., and gt;25% conversion efficiency) thin-film PV modules will also be assessed, along with critical issues associated with their development

Thin-film technology development for the PowerSphere

International Nuclear Information System (INIS)

Simburger, Edward J.; Matsumoto, James H.; Giants, Thomas W.; Garcia, Alexander; Liu, Simon; Rawal, Suraj P.; Perry, Alan R.; Marshall, Craig H.; Lin, John K.; Scarborough, Stephen E.; Curtis, Henry B.; Kerslake, Thomas W.; Peterson, Todd T.

2005-01-01

The PowerSphere concept consists of a relatively large spherical solar array, which would be deployed from a microsatellite. The PowerSphere will enable microsatellite missions across NASA enterprises and DoD missions by providing ample electric power at an affordable cost. The PowerSphere design provides attitude-independent electric power and thermal control for an enclosed microsatellite payload. The specific power design is scalable, robust in high radiation environments and provides sufficient electric power to allow the use of electric propulsion. Electric propulsion enables precise positioning of microsatellites, which is required for inspectors that would be deployed to observe the International Space Station, Space Shuttle or large unmanned spacecraft

High power Co3O4/ZnO p–n type piezoelectric transducer

International Nuclear Information System (INIS)

Hu, Yuh-Chung; Lee, Tsung-Han; Chang, Pei-Zen; Su, Pei-Chen

2015-01-01

Enhancing the output power of piezoelectric transducer is essential in order to supply sufficient and sustainable power to wireless sensor nodes or electronic devices. In this work, a Co 3 O 4 /ZnO p–n type power piezoelectric transducer which can be operated at low frequencies has been developed by utilizing n-type semiconducting zinc oxide (ZnO) and p-type semiconducting tricobalt tetroxide (Co 3 O 4 ). We utilize ZnO to be the piezoelectric transducer and build a multi-layer (Au/Co 3 O 4 /ZnO/Ti) thin film structure. The ZnO thin film with preferred orientation along the (002) plane was deposited under optimized deposition conditions on the flexible titanium (Ti) foil with thickness of 80 μm. The Co 3 O 4 /ZnO interface forms a p–n junction and increases the difference in Fermi levels between the two electrodes, resulting in the great enhancement of output power. The measured output power of the p–n type piezoelectric transducer with optimal resistance of 100 kΩ is 10.4 μW at low operating frequency of 37 Hz, which is 10.9 times of output power of ZnO piezoelectric transducers. - Highlights: • Deposited zinc oxide performed good piezoelectric coefficient. • ZnO thin film with preferred orientation along the (002) plane was deposited. • A p–n type piezoelectric transducer with enhanced output power was fabricated. • 10.9 times increment in output power was obtained. • Increase of difference in Fermi level and p–n junction formation was explained

Poly(3,4-ethylenedioxythiophene) nanotubes as electrode materials for a high-powered supercapacitor

International Nuclear Information System (INIS)

Liu Ran; Cho, Seung Il; Lee, Sang Bok

2008-01-01

We report the fast charging/discharging capability of poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes during the redox process and their potential application to a high-powered supercapacitor. PEDOT nanotubes were electrochemically synthesized in a porous alumina membrane, and their structures were characterized using electron microscopes. Cyclic voltammetry was used to characterize the specific capacitance of the PEDOT nanotubes at various scan rates. A type I supercapacitor (two symmetric electrodes) based on PEDOT nanotube electrodes was fabricated, and its energy density and power density were evaluated by galvanostatic charge/discharge cycles at various current densities. We show that the PEDOT-nanotube-based supercapacitor can achieve a high power density of 25 kW kg -1 while maintaining 80% energy density (5.6 W h kg -1 ). This high power capability is attributed to the fast charge/discharge of nanotubular structures: hollow nanotubes allow counter-ions to readily penetrate into the polymer and access their internal surfaces, while the thin wall provides a short diffusion distance to facilitate the ion transport. Impedance spectroscopy shows that nanotubes have much lower diffusional resistance to charging ions than solid nanowires shielded by an alumina template, providing supporting information for the high charging/discharging efficiency of nanotubular structures

High power klystrons for efficient reliable high power amplifiers

Science.gov (United States)

Levin, M.

1980-11-01

This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

High power beam profile monitor with optical transition radiation

International Nuclear Information System (INIS)

Denard, J.C.; Piot, P.; Capek, K.; Feldl, E.

1997-01-01

A simple monitor has been built to measure the profile of the high power beam (800 kW) delivered by the CEBAF accelerator at Jefferson Lab. The monitor uses the optical part of the forward transition radiation emitted from a thin carbon foil. The small beam size to be measured, about 100 μm, is challenging not only for the power density involved but also for the resolution the instrument must achieve. An important part of the beam instrumentation community believes the radiation being emitted into a cone of characteristic angle 1/γ is originated from a region of transverse dimension roughly λγ; thus the apparent size of the source of transition radiation would become very large for highly relativistic particles. This monitor measures 100 μm beam sizes that are much smaller than the 3.2 mm λγ limit; it confirms the statement of Rule and Fiorito that optical transition radiation can be used to image small beams at high energy. The present paper describes the instrument and its performance. The authors tested the foil in, up to 180 μA of CW beam without causing noticeable beam loss, even at 800 MeV, the lowest CEBAF energy

High-mobility pyrene-based semiconductor for organic thin-film transistors.

Science.gov (United States)

Cho, Hyunduck; Lee, Sunyoung; Cho, Nam Sung; Jabbour, Ghassan E; Kwak, Jeonghun; Hwang, Do-Hoon; Lee, Changhee

2013-05-01

Numerous conjugated oligoacenes and polythiophenes are being heavily studied in the search for high-mobility organic semiconductors. Although many researchers have designed fused aromatic compounds as organic semiconductors for organic thin-film transistors (OTFTs), pyrene-based organic semiconductors with high mobilities and on-off current ratios have not yet been reported. Here, we introduce a new pyrene-based p-type organic semiconductor showing liquid crystal behavior. The thin film characteristics of this material are investigated by varying the substrate temperature during the deposition and the gate dielectric condition using the surface modification with a self-assembled monolayer, and systematically studied in correlation with the performances of transistor devices with this compound. OTFT fabricated under the optimum deposition conditions of this compound, namely, 1,6-bis(5'-octyl-2,2'-bithiophen-5-yl)pyrene (BOBTP) shows a high-performance transistor behavior with a field-effect mobility of 2.1 cm(2) V(-1) s(-1) and an on-off current ratio of 7.6 × 10(6) and enhanced long-term stability compared to the pentacene thin-film transistor.

High-power diode laser bars as pump sources for fiber lasers and amplifiers (Invited Paper)

Science.gov (United States)

Bonati, G.; Hennig, P.; Wolff, D.; Voelckel, H.; Gabler, T.; Krause, U.; T'nnermann, A.; Reich, M.; Limpert, J.; Werner, E.; Liem, A.

2005-04-01

Fiber lasers are pumped by fibercoupled, multimode single chip devices at 915nm. That"s what everybody assumes when asked for the type of fiber laser pumps and it was like this for many years. Coming up as an amplifier for telecom applications, the amount of pump power needed was in the range of several watts. Highest pump powers for a limited market entered the ten watts range. This is a range of power that can be covered by highly reliable multimode chips, that have to survive up to 25 years, e.g. in submarine applications. With fiber lasers entering the power range and the application fields of rod and thin disc lasers, the amount of pump power needed raised into the area of several hundred watts. In this area of pump power, usually bar based pumps are used. This is due to the much higher cost pressure of the industrial customers compared to telecom customers. We expect more then 70% of all industrial systems to be pumped by diode laser bars. Predictions that bar based pumps survive for just a thousand hours in cw-operation and fractions of this if pulsed are wrong. Bar based pumps have to perform on full power for 10.000h on Micro channel heat sinks and 20.000h on passive heatsinks in industrial applications, and they do. We will show a variety of data, "real" long time tests and statistics from the JENOPTIK Laserdiode as well as data of thousands of bars in the field, showing that bar based pumps are not just well suitable for industrial applications on high power levels, but even showing benefits compared to chip based pumps. And it"s reasonable, that the same objectives of cost effectiveness, power and lifetime apply as well to thin disc, rod and slab lasers as to fiber lasers. Due to the pumping of fiber lasers, examples will be shown, how to utilize bars for high brightness fiber coupling. In this area, the automation is on its way to reduce the costs on the fibercoupling, similar to what had been done in the single chip business. All these efforts are

High-density plasma etching characteristics of indium-gallium-zinc oxide thin films in CF4/Ar plasma

International Nuclear Information System (INIS)

Joo, Young-Hee; Kim, Chang-Il

2015-01-01

We investigated the etching process of indium-gallium-zinc oxide (IGZO) thin films in an inductively coupled plasma system. The dry etching characteristics of the IGZO thin films were studied by varying the CF 4 /Ar gas mixing ratio, RF power, DC-bias voltage, and process pressure. We determined the following optimized process conditions: an RF power of 700 W, a DC-bias voltage of − 150 V, and a process pressure of 2 Pa. A maximum etch rate of 25.63 nm/min for the IGZO thin films was achieved in a plasma with CF 4 /Ar(= 25:75), and the selectivity of IGZO to Al and TiN was found to be 1.3 and 0.7, respectively. We determined the ionic composition of the CF 4 /Ar plasma using optical emission spectroscopy. Analysis of chemical reactions at the IGZO thin film surfaces was performed using X-ray photoelectron spectroscopy. - Highlights: • IGZO thin film was etched by CF 4 /Ar plasma as a function of gas mixing ratio. • IGZO bonds were broken Ar + sputtering and then reacted with the C-F x radicals. • The physical sputtering is dominant in etch control compared with chemical etching

Influences of the RF power ratio on the optical and electrical properties of GZO thin films by DC coupled RF magnetron sputtering at room temperature

Energy Technology Data Exchange (ETDEWEB)

Peng, Shou [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China); Yao, Tingting, E-mail: yaott0815@163.com [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China); Yang, Yong; Zhang, Kuanxiang; Jiang, Jiwen; Jin, Kewu; Li, Gang; Cao, Xin; Xu, Genbao; Wang, Yun [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China)

2016-12-15

Ga-doped zinc oxide (GZO) thin films were deposited by closed field unbalanced DC coupled RF magnetron sputtering system at room temperature. The RF sputtering power ratio was adjusted from 0% to 100%. The crystal structure, surface morphology, transmittance and electrical resistivity of GZO films mainly influenced by RF sputtering power ratio were investigated by X-ray diffractometer, scanning electronic microscope, ultraviolet-visible spectrophotometer and Hall effect measurement. The research results indicate that the increasing RF power ratio can effectively reduce the discharge voltage of system and increase the ionizing rate of particles. Meanwhile, the higher RF power ratio can increase the carrier mobility in GZO thin film and improve the optical and electrical properties of GZO thin film significantly. Within the optimal discharge voltage window, the film deposits at 80% RF power ratio exhibits the lowest resistivity of 2.6×10{sup −4} Ω cm. We obtain the GZO film with the best average optical transmittance is approximately 84% in the visible wavelength. With the increasing RF power ratio, the densification of GZO film is enhanced. The densification of GZO film is decrease when the RF power ratio is 100%.

Erosion corrosion in power plant piping systems - Calculation code for predicting wall thinning

International Nuclear Information System (INIS)

Kastner, W.; Erve, M.; Henzel, N.; Stellwag, B.

1990-01-01

Extensive experimental and theoretical investigations have been performed to develop a calculation code for wall thinning due to erosion corrosion in power plant piping systems. The so-called WATHEC code can be applied to single-phase water flow as well as to two-phase water/steam flow. Only input data which are available to the operator of the plant are taken into consideration. Together with a continuously updated erosion corrosion data base the calculation code forms one element of a weak point analysis for power plant piping systems which can be applied to minimize material loss due to erosion corrosion, reduce non-destructive testing and curtail monitoring programs for piping systems, recommend life-extending measures. (author). 12 refs, 17 figs

Cellulose triacetate, thin film dielectric capacitor

Science.gov (United States)

Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

1995-01-01

Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

High-power klystrons

Science.gov (United States)

Siambis, John G.; True, Richard B.; Symons, R. S.

1994-05-01

Novel emerging applications in advanced linear collider accelerators, ionospheric and atmospheric sensing and modification and a wide spectrum of industrial processing applications, have resulted in microwave tube requirements that call for further development of high power klystrons in the range from S-band to X-band. In the present paper we review recent progress in high power klystron development and discuss some of the issues and scaling laws for successful design. We also discuss recent progress in electron guns with potential grading electrodes for high voltage with short and long pulse operation via computer simulations obtained from the code DEMEOS, as well as preliminary experimental results. We present designs for high power beam collectors.

Colored ultra-thin hybrid photovoltaics with high quantum efficiency for decorative PV applications (Presentation Recording)

Science.gov (United States)

Guo, L. Jay

2015-10-01

This talk will describe an approach to create architecturally compatible and decorative thin-film-based hybrid photovoltaics [1]. Most current solar panels are fabricated via complex processes using expensive semiconductor materials, and they are rigid and heavy with a dull, black appearance. As a result of their non-aesthetic appearance and weight, they are primarily installed on rooftops to minimize their negative impact on building appearance. Recently we introduced dual-function solar cells based on ultra-thin dopant-free amorphous silicon embedded in an optical cavity that not only efficiently extract the photogenerated carriers but also display distinctive colors with the desired angle-insensitive appearances [1,2]. The angle-insensitive behavior is the result of an interesting phase cancellation effect in the optical cavity with respect to angle of light propagation [3]. In order to produce the desired optical effect, the semiconductor layer should be ultra-thin and the traditional doped layers need to be eliminated. We adopted the approach of employing charge transport/blocking layers used in organic solar cells to meet this demand. We showed that the ultra-thin (6 to 31 nm) undoped amorphous silicon/organic hybrid solar cell can transmit desired wavelength of light and that most of the absorbed photons in the undoped a-Si layer contributed to the extracted electric charges. This is because the a-Si layer thickness is smaller than the charge diffusion length, therefore the electron-hole recombination is strongly suppressed in such ultra-thin layer. Reflective colored PVs can be made in a similar fashion. Light-energy-harvesting colored signage was demonstrated. Furthermore, a cascaded photovoltaics scheme based on tunable spectrum splitting can be employed to increase power efficiency by absorbing a broader band of light energy. Our work provides a guideline for optimizing a photoactive layer thickness in high efficiency hybrid PV design, which can be

Switching power converters medium and high power

CERN Document Server

Neacsu, Dorin O

2013-01-01

An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

High-Performance Single-Crystalline Perovskite Thin-Film Photodetector

KAUST Repository

Yang, Zhenqian

2018-01-10

The best performing modern optoelectronic devices rely on single-crystalline thin-film (SC-TF) semiconductors grown epitaxially. The emerging halide perovskites, which can be synthesized via low-cost solution-based methods, have achieved substantial success in various optoelectronic devices including solar cells, lasers, light-emitting diodes, and photodetectors. However, to date, the performance of these perovskite devices based on polycrystalline thin-film active layers lags behind the epitaxially grown semiconductor devices. Here, a photodetector based on SC-TF perovskite active layer is reported with a record performance of a 50 million gain, 70 GHz gain-bandwidth product, and a 100-photon level detection limit at 180 Hz modulation bandwidth, which as far as we know are the highest values among all the reported perovskite photodetectors. The superior performance of the device originates from replacing polycrystalline thin film by a thickness-optimized SC-TF with much higher mobility and longer recombination time. The results indicate that high-performance perovskite devices based on SC-TF may become competitive in modern optoelectronics.

Sub-second photonic processing of solution-deposited single layer and heterojunction metal oxide thin-film transistors using a high-power xenon flash lamp

KAUST Repository

Tetzner, Kornelius

2017-11-01

We report the fabrication of solution-processed In2O3 and In2O3/ZnO heterojunction thin-film transistors (TFTs) where the precursor materials were converted to their semiconducting state using high power light pulses generated by a xenon flash lamp. In2O3 TFTs prepared on glass substrates exhibited low-voltage operation (≤2 V) and a high electron mobility of ∼6 cm2 V−1 s−1. By replacing the In2O3 layer with a photonically processed In2O3/ZnO heterojunction, we were able to increase the electron mobility to 36 cm2 V−1 s−1, while maintaining the low-voltage operation. Although the level of performance achieved in these devices is comparable to control TFTs fabricated via thermal annealing at 250 °C for 1 h, the photonic treatment approach adopted here is extremely rapid with a processing time of less than 18 s per layer. With the aid of a numerical model we were able to analyse the temperature profile within the metal oxide layer(s) upon flashing revealing a remarkable increase of the layer\\'s surface temperature to ∼1000 °C within ∼1 ms. Despite this, the backside of the glass substrate remains unchanged and close to room temperature. Our results highlight the applicability of the method for the facile manufacturing of high performance metal oxide transistors on inexpensive large-area substrates.

High efficiency thin-film solar cells for space applications: challenges and opportunities

NARCIS (Netherlands)

Leest, R.H. van

2017-01-01

In theory high efficiency thin-film III-V solar cells obtained by the epitaxial lift-off (ELO) technique offer excellent characteristics for application in space solar panels. The thesis describes several studies that investigate the space compatibility of the thin-film solar cell design developed

MATERIAL AND PROCESS DEVELOPMENT LEADING TO ECONOMICAL HIGH-PERFORMANCE THIN-FILM SOLID OXIDE FUEL CELLS. Final Technical Report (October 2000 - December 2003)

International Nuclear Information System (INIS)

Jie Guan; Nguyen Minh

2003-01-01

This report summarizes the results of the work conducted under the program: ''Material and Process Development Leading to Economical High-Performance Thin-Film Solid Oxide Fuel Cells'' under contract number DE-AC26-00NT40711. The program goal is to advance materials and processes that can be used to produce economical, high-performance solid oxide fuel cells (SOFC) capable of achieving extraordinary high power densities at reduced temperatures. Under this program, anode-supported thin electrolyte based on lanthanum gallate (LSMGF) has been developed using tape-calendering process. The fabrication parameters such as raw materials characteristics, tape formulations and sintering conditions have been evaluated. Dense anode supported LSGMF electrolytes with thickness range of 10-50 micron have been fabricated. High performance cathode based on Sr 0.5 Sm 0.5 CoO 3 (SSC) has been developed. Polarization of ∼0.23 ohm-cm 2 has been achieved at 600 C with Sr 0.5 Sm 0.5 CoO 3 cathode. The high-performance SSC cathode and thin gallate electrolyte have been integrated into single cells and cell performance has been characterized. Tested cells to date generally showed low performance because of low cell OCVs and material interactions between NiO in the anode and lanthanum gallate electrolyte

Sputtered thin films for high density tape recording

NARCIS (Netherlands)

Nguyen, L.T.

This thesis describes the investigation of sputtered thin film media for high density tape recording. As discussed in Chapter 1, to meet the tremendous demand of data storage, the density of recording tape has to be increased continuously. For further increasing the bit density the key factors are:

Designing High-Efficiency Thin Silicon Solar Cells Using Parabolic-Pore Photonic Crystals

Science.gov (United States)

Bhattacharya, Sayak; John, Sajeev

2018-04-01

We demonstrate the efficacy of wave-interference-based light trapping and carrier transport in parabolic-pore photonic-crystal, thin-crystalline silicon (c -Si) solar cells to achieve above 29% power conversion efficiencies. Using a rigorous solution of Maxwell's equations through a standard finite-difference time domain scheme, we optimize the design of the vertical-parabolic-pore photonic crystal (PhC) on a 10 -μ m -thick c -Si solar cell to obtain a maximum achievable photocurrent density (MAPD) of 40.6 mA /cm2 beyond the ray-optical, Lambertian light-trapping limit. For a slanted-parabolic-pore PhC that breaks x -y symmetry, improved light trapping occurs due to better coupling into parallel-to-interface refraction modes. We achieve the optimum MAPD of 41.6 mA /cm2 for a tilt angle of 10° with respect to the vertical axis of the pores. This MAPD is further improved to 41.72 mA /cm2 by introducing a 75-nm SiO2 antireflective coating on top of the solar cell. We use this MAPD and the associated charge-carrier generation profile as input for a numerical solution of Poisson's equation coupled with semiconductor drift-diffusion equations using a Shockley-Read-Hall and Auger recombination model. Using experimentally achieved surface recombination velocities of 10 cm /s , we identify semiconductor doping profiles that yield power conversion efficiencies over 29%. Practical considerations of additional upper-contact losses suggest efficiencies close to 28%. This improvement beyond the current world record is largely due to an open-circuit voltage approaching 0.8 V enabled by reduced bulk recombination in our thin silicon architecture while maintaining a high short-circuit current through wave-interference-based light trapping.

Sputtered highly oriented PZT thin films for MEMS applications

Science.gov (United States)

Kalpat, Sriram S.

Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate

Investigation of high- k yttrium copper titanate thin films as alternative gate dielectrics

International Nuclear Information System (INIS)

Monteduro, Anna Grazia; Ameer, Zoobia; Rizzato, Silvia; Martino, Maurizio; Caricato, Anna Paola; Maruccio, Giuseppe; Tasco, Vittorianna; Lekshmi, Indira Chaitanya; Hazarika, Abhijit; Choudhury, Debraj; Sarma, D D

2016-01-01

Nearly amorphous high- k yttrium copper titanate thin films deposited by laser ablation were investigated in both metal–oxide–semiconductor (MOS) and metal–insulator–metal (MIM) junctions in order to assess the potentialities of this material as a gate oxide. The trend of dielectric parameters with film deposition shows a wide tunability for the dielectric constant and AC conductivity, with a remarkably high dielectric constant value of up to 95 for the thick films and conductivity as low as 6  ×  10 −10 S cm −1 for the thin films deposited at high oxygen pressure. The AC conductivity analysis points out a decrease in the conductivity, indicating the formation of a blocking interface layer, probably due to partial oxidation of the thin films during cool-down in an oxygen atmosphere. Topography and surface potential characterizations highlight differences in the thin film microstructure as a function of the deposition conditions; these differences seem to affect their electrical properties. (paper)

Fabrication of high-quality single-crystal Cu thin films using radio-frequency sputtering.

Science.gov (United States)

Lee, Seunghun; Kim, Ji Young; Lee, Tae-Woo; Kim, Won-Kyung; Kim, Bum-Su; Park, Ji Hun; Bae, Jong-Seong; Cho, Yong Chan; Kim, Jungdae; Oh, Min-Wook; Hwang, Cheol Seong; Jeong, Se-Young

2014-08-29

Copper (Cu) thin films have been widely used as electrodes and interconnection wires in integrated electronic circuits, and more recently as substrates for the synthesis of graphene. However, the ultra-high vacuum processes required for high-quality Cu film fabrication, such as molecular beam epitaxy (MBE), restricts mass production with low cost. In this work, we demonstrated high-quality Cu thin films using a single-crystal Cu target and radio-frequency (RF) sputtering technique; the resulting film quality was comparable to that produced using MBE, even under unfavorable conditions for pure Cu film growth. The Cu thin film was epitaxially grown on an Al2O3 (sapphire) (0001) substrate, and had high crystalline orientation along the (111) direction. Despite the 10(-3) Pa vacuum conditions, the resulting thin film was oxygen free due to the high chemical stability of the sputtered specimen from a single-crystal target; moreover, the deposited film had >5× higher adhesion force than that produced using a polycrystalline target. This fabrication method enabled Cu films to be obtained using a simple, manufacturing-friendly process on a large-area substrate, making our findings relevant for industrial applications.

Crystal orientation dependent thermoelectric properties of highly oriented aluminum-doped zinc oxide thin films

KAUST Repository

Abutaha, Anas I.

2013-02-06

We demonstrate that the thermoelectric properties of highly oriented Al-doped zinc oxide (AZO) thin films can be improved by controlling their crystal orientation. The crystal orientation of the AZO films was changed by changing the temperature of the laser deposition process on LaAlO3 (100) substrates. The change in surface termination of the LaAlO3 substrate with temperature induces a change in AZO film orientation. The anisotropic nature of electrical conductivity and Seebeck coefficient of the AZO films showed a favored thermoelectric performance in c-axis oriented films. These films gave the highest power factor of 0.26 W m−1 K−1 at 740 K.

High-density plasma etching characteristics of indium-gallium-zinc oxide thin films in CF{sub 4}/Ar plasma

Energy Technology Data Exchange (ETDEWEB)

Joo, Young-Hee; Kim, Chang-Il

2015-05-29

We investigated the etching process of indium-gallium-zinc oxide (IGZO) thin films in an inductively coupled plasma system. The dry etching characteristics of the IGZO thin films were studied by varying the CF{sub 4}/Ar gas mixing ratio, RF power, DC-bias voltage, and process pressure. We determined the following optimized process conditions: an RF power of 700 W, a DC-bias voltage of − 150 V, and a process pressure of 2 Pa. A maximum etch rate of 25.63 nm/min for the IGZO thin films was achieved in a plasma with CF{sub 4}/Ar(= 25:75), and the selectivity of IGZO to Al and TiN was found to be 1.3 and 0.7, respectively. We determined the ionic composition of the CF{sub 4}/Ar plasma using optical emission spectroscopy. Analysis of chemical reactions at the IGZO thin film surfaces was performed using X-ray photoelectron spectroscopy. - Highlights: • IGZO thin film was etched by CF{sub 4}/Ar plasma as a function of gas mixing ratio. • IGZO bonds were broken Ar{sup +} sputtering and then reacted with the C-F{sub x} radicals. • The physical sputtering is dominant in etch control compared with chemical etching.

Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

CERN Document Server

Ahuja, Sumit; Shukla, Sandeep Kumar

2012-01-01

Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

Ultra-low power, highly uniform polymer memory by inserted multilayer graphene electrode

International Nuclear Information System (INIS)

Jang, Byung Chul; Kim, Jong Yun; Koo, Beom Jun; Yang, Sang Yoon; Choi, Sung-Yool; Seong, Hyejeong; Im, Sung Gap; Kim, Sung Kyu

2015-01-01

Filament type resistive random access memory (RRAM) based on polymer thin films is a promising device for next generation, flexible nonvolatile memory. However, the resistive switching nonuniformity and the high power consumption found in the general filament type RRAM devices present critical issues for practical memory applications. Here, we introduce a novel approach not only to reduce the power consumption but also to improve the resistive switching uniformity in RRAM devices based on poly(1,3,5-trimethyl-3,4,5-trivinyl cyclotrisiloxane) by inserting multilayer graphene (MLG) at the electrode/polymer interface. The resistive switching uniformity was thereby significantly improved, and the power consumption was markedly reduced by 250 times. Furthermore, the inserted MLG film enabled a transition of the resistive switching operation from unipolar resistive switching to bipolar resistive switching and induced self-compliance behavior. The findings of this study can pave the way toward a new area of application for graphene in electronic devices. (paper)

Effect of Sb content on the thermoelectric properties of annealed CoSb_3 thin films deposited via RF co-sputtering

International Nuclear Information System (INIS)

Ahmed, Aziz; Han, Seungwoo

2017-01-01

Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb_3 phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb_2 phase possess the largest power factor. - Abstract: A series of CoSb_3 thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb_3 thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb_2 and CoSb_3 components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb_3 thin films. The CoSb_2 phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb_3 thin films. We report maximum power factor of 7.92 mW/m K"2 for the CoSb_2-containing mixed phase thin film and 1.26 mW/m K"2 for the stoichiometric CoSb_3 thin film.

High powered pulsed plasma enhanced deposition of thin film semiconductor and optical materials

International Nuclear Information System (INIS)

Llewellyn, I.P.; Sheach, K.J.A.; Heinecke, R.A.

1993-01-01

A glow discharge deposition technique is described which allows the deposition of a large range of high quality materials without the requirement for substrate heating. The method is differentiated from conventional plasma deposition techniques in that a much higher degree of dissociation is achieved in the gases prior to deposition, such that thermally activated surface reactions are no longer required in order to produce a dense film. The necessary discharge intensity (>300Wcm -3 ) is achieved using a high power radio frequency generator which is pulsed at a low duty cycle (1%) to keep the average energy of the discharge low (100W), in order to avoid the discharge heating the substrate. In addition, by varying the gas composition between discharge pulses, layered structures of materials can be produced, with a disordered interface about 8 A thick. Various uses of the technique in semiconductor and optical filter production are described, and the properties of films deposited using these technique are presented. (orig.)

Highly oriented thin films of a substituted oligo(para-phenylenevinylene) on friction-transferred PTFE substrates

NARCIS (Netherlands)

Gill, R.E; Hadziioannou, G; Lang, P.; Garnier, F.; Wittmann, J.C.

Communication: Highly oriented thin films of oligo(p-phenylenevinylene)s, oligoPPVs, provide information about the structure of polyPPV and structure-property relationships. It is shown that deposition of a substituted oligoPPV onto highly preoriented PTFE substrates leads to highly oriented thin

Knife-edge thin film field emission cathodes

International Nuclear Information System (INIS)

Lee, B.; Demroff, H.P.; Drew, M.M.; Elliott, T.S.; Mazumdar, T.K.; McIntyre, P.M.; Pang, Y.; Smith, D.D.; Trost, H.J.

1993-01-01

Cathodes made of thin-film field emission arrays (FEA) have the advantages of high current density, pulsed emission, and low bias voltage operation. The authors have developed a technology to fabricate knife-edge field emission cathodes on (110) silicon wafers. The emitter geometry is optimized for efficient modulation at high frequency. Cathode fabrication progress and preliminary analysis of their applications in RF power sources are presented

High power communication satellites power systems study

International Nuclear Information System (INIS)

Josloff, A.T.; Peterson, J.R.

1994-01-01

This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

Highly stable thin film transistors using multilayer channel structure

KAUST Repository

Nayak, Pradipta K.; Wang, Zhenwei; Anjum, Dalaver H.; Hedhili, Mohamed N.; Alshareef, Husam N.

2015-01-01

We report highly stable gate-bias stress performance of thin film transistors (TFTs) using zinc oxide (ZnO)/hafnium oxide (HfO2) multilayer structure as the channel layer. Positive and negative gate-bias stress stability of the TFTs was measured

Fabricating high-energy quantum dots in ultra-thin LiFePO4 nanosheets using a multifunctional high-energy biomolecule-ATP

DEFF Research Database (Denmark)

Zhang, X.D.; Bi, Z.Y.; He, W.

2014-01-01

By using a multifunctional high-energy biomolecule—adenosine triphosphate (ATP)—we fabricated highenergy quantum dots (HEQDs) with a feature size of less than 10 nm and used them in high-power lithium-ion batteries. We introduced high-energy phosphate bonds into the crystal structure of LiFePO4...... nanoparticles and synthesized the mesoporous biocarbon nanowire coated LiFePO4 with HEQDs (MBCNW-LFP-HEQDs) by using ATP as a phosphorus source, a nucleating agent, a structural template and a biocarbon source. HEGDs were homogeneously formed inside the ultra-thin LiFePO4 nanosheet and the mesoporous biocarbon...... nanowire network structure was coated on the surface of the nanosheet. In LiFePO4 nanoparticles, HEQDs result in more storage sites of Li+ ions and easier transfer kinetics of electrons and lithium ions, where the kinetic transformation path between LiFePO4 and FePO4 is rather different from the path...

CSTI High Capacity Power

International Nuclear Information System (INIS)

Winter, J.M.

1989-01-01

The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed

Effect of Sb content on the thermoelectric properties of annealed CoSb{sub 3} thin films deposited via RF co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Aziz, E-mail: aziz_ahmed@ust.ac.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Han, Seungwoo, E-mail: swhan@kimm.re.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

2017-06-30

Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb{sub 3} phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb{sub 2} phase possess the largest power factor. - Abstract: A series of CoSb{sub 3} thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb{sub 3} thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb{sub 2} and CoSb{sub 3} components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb{sub 3} thin films. The CoSb{sub 2} phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb{sub 3} thin films. We report maximum power factor of 7.92 mW/m K{sup 2} for the CoSb{sub 2}-containing mixed phase thin film and 1

The influence of sputtering power and O2/Ar flow ratio on the performance and stability of Hf-In-Zn-O thin film transistors under illumination

International Nuclear Information System (INIS)

Kim, Hyun-Suk; Park, Kyung-Bae; Son, Kyoung Seok; Park, Joon Seok; Maeng, Wan-Joo; Kim, Tae Sang; Lee, Kwang-Hee; Kim, Eok Su; Lee, Jiyoul; Suh, Joonki; Seon, Jong-Baek; Ryu, Myung Kwan; Lee, Sang Yoon; Lee, Kimoon; Im, Seongil

2010-01-01

The performance and stability of amorphous HfInZnO thin film transistors under visible light illumination were studied. The extent of device degradation upon negative bias stress with the presence of visible light is found to be strongly sensitive to the extent of photoelectric effect in the oxide semiconductor. Highly stable devices were fabricated by optimizing the deposition conditions of HfInZnO films, where the combination of high sputtering power and high O 2 /Ar gas flow ratio was found to result in the highest stability under bias stress experiments.

Restructuring in block copolymer thin films

DEFF Research Database (Denmark)

Posselt, Dorthe; Zhang, Jianqi; Smilgies, Detlef-M.

2017-01-01

Block copolymer (BCP) thin films have been proposed for a number of nanotechnology applications, such as nanolithography and as nanotemplates, nanoporous membranes and sensors. Solvent vapor annealing (SVA) has emerged as a powerful technique for manipulating and controlling the structure of BCP...... thin films, e.g., by healing defects, by altering the orientation of the microdomains and by changing the morphology. Due to high time resolution and compatibility with SVA environments, grazing-incidence small-angle X-ray scattering (GISAXS) is an indispensable technique for studying the SVA process......, providing information of the BCP thin film structure both laterally and along the film normal. Especially, state-of-the-art combined GISAXS/SVA setups at synchrotron sources have facilitated in situ and real-time studies of the SVA process with a time resolution of a few seconds, giving important insight...

High quality atomically thin PtSe2 films grown by molecular beam epitaxy

Science.gov (United States)

Yan, Mingzhe; Wang, Eryin; Zhou, Xue; Zhang, Guangqi; Zhang, Hongyun; Zhang, Kenan; Yao, Wei; Lu, Nianpeng; Yang, Shuzhen; Wu, Shilong; Yoshikawa, Tomoki; Miyamoto, Koji; Okuda, Taichi; Wu, Yang; Yu, Pu; Duan, Wenhui; Zhou, Shuyun

2017-12-01

Atomically thin PtSe2 films have attracted extensive research interests for potential applications in high-speed electronics, spintronics and photodetectors. Obtaining high quality thin films with large size and controlled thickness is critical. Here we report the first successful epitaxial growth of high quality PtSe2 films by molecular beam epitaxy. Atomically thin films from 1 ML to 22 ML have been grown and characterized by low-energy electron diffraction, Raman spectroscopy and x-ray photoemission spectroscopy. Moreover, a systematic thickness dependent study of the electronic structure is revealed by angle-resolved photoemission spectroscopy (ARPES), and helical spin texture is revealed by spin-ARPES. Our work provides new opportunities for growing large size single crystalline films to investigate the physical properties and potential applications of PtSe2.

Influence of RF power on the properties of sputtered ZnO:Al thin films

Energy Technology Data Exchange (ETDEWEB)

Antony, Aldrin; Carreras, Paz; Keitzl, Thomas; Roldan, Ruben; Nos, Oriol; Frigeri, Paolo; Asensi, Jose Miguel; Bertomeu, Joan [Grup d' Energia Solar, Universitat de Barcelona (Spain)

2010-07-15

Transparent conducting, aluminium doped zinc oxide thin films (ZnO:Al) were deposited by radio frequency (RF) magnetron sputtering. The RF power was varied from 60 to 350 W whereas the substrate temperature was kept at 160 C. The structural, electrical and optical properties of the as-deposited films were found to be influenced by the deposition power. The X-ray diffraction analysis showed that all the films have a strong preferred orientation along the [001] direction. The crystallite size was varied from 14 to 36 nm, however no significant change was observed in the case of lattice constant. The optical band gap varied in the range 3.44-3.58 eV. The lowest resistivity of 1.2 x 10{sup -3}{omega} cm was shown by the films deposited at 250 W. The mobility of the films was found to increase with the deposition power. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Process parameter impact on properties of sputtered large-area Mo bilayers for CIGS thin film solar cell applications

Energy Technology Data Exchange (ETDEWEB)

Badgujar, Amol C.; Dhage, Sanjay R., E-mail: dhage@arci.res.in; Joshi, Shrikant V.

2015-08-31

Copper indium gallium selenide (CIGS) has emerged as a promising candidate for thin film solar cells, with efficiencies approaching those of silicon-based solar cells. To achieve optimum performance in CIGS solar cells, uniform, conductive, stress-free, well-adherent, reflective, crystalline molybdenum (Mo) thin films with preferred orientation (110) are desirable as a back contact on large area glass substrates. The present study focuses on cylindrical rotating DC magnetron sputtered bilayer Mo thin films on 300 mm × 300 mm soda lime glass (SLG) substrates. Key sputtering variables, namely power and Ar gas flow rates, were optimized to achieve best structural, electrical and optical properties. The Mo films were comprehensively characterized and found to possess high degree of thickness uniformity over large area. Best crystallinity, reflectance and sheet resistance was obtained at high sputtering powers and low argon gas flow rates, while mechanical properties like adhesion and residual stress were found to be best at low sputtering power and high argon gas flow rate, thereby indicating a need to arrive at a suitable trade-off during processing. - Highlights: • Sputtering of bilayer molybdenum thin films on soda lime glass • Large area deposition using rotating cylindrical direct current magnetron • Trade of sputter process parameters power and pressure • High uniformity of thickness and best electrical properties obtained • Suitable mechanical and optical properties of molybdenum are achieved for CIGS application.

The use of thin-section high-resolution CT in pediatric pulmonary disease

International Nuclear Information System (INIS)

Hay, T.C.; Horgan, J.G.; Rumack, C.M.

1989-01-01

High-resolution thin-section CT of the chest was used successfully to characterize the extent of pulmonary disease. This paper reports on a study in which ten children with chronic lung disorders (including cystic fibrosis, reactive airway disease, and idiopathic disease) were evaluated to test the accuracy of the posteroanterior and lateral chest CT, with both thick (1 cm) and thin (1-3 mm) sections. Unsuspected bronchiectasis was established n two patients with reactive airway disease, and the extent of bronchiectasis in other patients was best defined on thin-section CT. Technique was crucial for an accurate study, and magnification views of each lung were useful. Thin-section CT of the chest was helpful in defining and localizing the extent of these pulmonary disorders

High to ultra-high power electrical energy storage.

Science.gov (United States)

Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

2011-12-14

High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

Science.gov (United States)

Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

2016-08-10

Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels.

Development of pipe wall thinning prediction software 'FALSET'

International Nuclear Information System (INIS)

Yoneda, Kimitoshi; Morita, Ryo; Inada, Fumio; Fujiwara, Kazutoshi

2012-01-01

Pipe wall thinning in power plants has been managed for maintaining plant integrity and safety with great importance. The target thinning phenomena are Flow Accelerated Corrosion (FAC) and Liquid Droplet Impingement Erosion (LDI). At present, the management is based on thinning rate and residual lifetime evaluation using pipe wall thickness measurement results. For the future, more safety and improvement in the management is required, and in this sense, prediction method of wall thinning is willing to be introduced. Therefore, prediction model of FAC and LDI have been constructed in CRIEPI, and to utilize these models to actual plant piping management easily, prediction software 'FALSET' is developed. FALSET has equipped with essential function for pipe wall thinning management in power plants, as follows; (1) Information and condition input of plant piping system and its component, (2) Wall thinning rate evaluation with CRIEPI's FAC/LDI prediction model, (3) Loading of wall thickness measurement data files and graphics of data trend, (4) Residual lifetime evaluation considering both measured and predicted thinning rate, (5) Statistical process and graphics of thinning rate and residual lifetime for multi-piping systems. With further verification and improvement of each function, there will be a perspective for this FALSET to be utilized as a management tool in power plants. (author)

Studies on the high electronic energy deposition in polyaniline thin films

International Nuclear Information System (INIS)

Deshpande, N.G.; Gudage, Y.G.; Vyas, J.C.; Singh, F.; Sharma, Ramphal

2008-01-01

We report here the physico-chemical changes brought about by high electronic energy deposition of gold ions in HCl doped polyaniline (PANI) thin films. PANI thin films were synthesized by in situ polymerization technique. The as-synthesized PANI thin films of thickness 160 nm were irradiated using Au 7+ ion of 100 MeV energy at different fluences, namely, 5 x 10 11 ions/cm 2 and 5 x 10 12 ions/cm 2 , respectively. A significant change was seen after irradiation in electrical and photo conductivity, which may be related to increased carrier concentration, and structural modifications in the polymer film. In addition, the high electronic energy deposition showed other effects like cross-linking of polymer chains, bond breaking and creation of defect sites. AFM observations revealed mountainous type features in all (before and after irradiation) PANI samples. The average size (diameter) and density of such mountainous clusters were found to be related with the ion fluence. The AFM profiles also showed change in the surface roughness of the films with respect to irradiation, which is one of the peculiarity of the high electronic energy deposition technique

Fabrication and electrical characterization of ultra-thin substrate IGBT

OpenAIRE

Guhathakurta, Jajnabalkya

2013-01-01

Current topics such as electro-mobility and renewable energy demand the development of power devices with high voltage and current ratings along with minimum switching losses. Amongst the power devices in today’s market, IGBTs have gained a lot of significance in this field over its competitors like Power MOSFETS and Thyristors. Today’s industry has recently taken a huge step in this direction to implement the use of thin-wafer technology for fabrication of IGBTs to reduce the on-resistance. ...

Ultra-low power thin film transistors with gate oxide formed by nitric acid oxidation method

International Nuclear Information System (INIS)

Kobayashi, H.; Kim, W. B.; Matsumoto, T.

2011-01-01

We have developed a low temperature fabrication method of SiO 2 /Si structure by use of nitric acid, i.e., nitric acid oxidation of Si (NAOS) method, and applied it to thin film transistors (TFT). A silicon dioxide (SiO 2 ) layer formed by the NAOS method at room temperature possesses 1.8 nm thickness, and its leakage current density is as low as that of thermally grown SiO 2 layer with the same thickness formed at ∼900 deg C. The fabricated TFTs possess an ultra-thin NAOS SiO 2 /CVD SiO 2 stack gate dielectric structure. The ultrathin NAOS SiO 2 layer effectively blocks a gate leakage current, and thus, the thickness of the gate oxide layer can be decreased from 80 to 20 nm. The thin gate oxide layer enables to decrease the operation voltage to 2 V (cf. the conventional operation voltage of TFTs with 80 nm gate oxide: 12 V) because of the low threshold voltages, i.e., -0.5 V for P-ch TFTs and 0.5 V for N-ch TFTs, and thus the consumed power decreases to 1/36 of that of the conventional TFTs. The drain current increases rapidly with the gate voltage, and the sub-threshold voltage is ∼80 mV/dec. The low sub-threshold swing is attributable to the thin gate oxide thickness and low interface state density of the NAOS SiO 2 layer. (authors)

High average power solid state laser power conditioning system

International Nuclear Information System (INIS)

Steinkraus, R.F.

1987-01-01

The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers

Reliable and repeatable bonding technology for high temperature automotive power modules for electrified vehicles

International Nuclear Information System (INIS)

Yoon, Sang Won; Shiozaki, Koji; Glover, Michael D; Mantooth, H Alan

2013-01-01

This paper presents the feasibility of highly reliable and repeatable copper–tin transient liquid phase (Cu–Sn TLP) bonding as applied to die attachment in high temperature operational power modules. Electrified vehicles are attracting particular interest as eco-friendly vehicles, but their power modules are challenged because of increasing power densities which lead to high temperatures. Such high temperature operation addresses the importance of advanced bonding technology that is highly reliable (for high temperature operation) and repeatable (for fabrication of advanced structures). Cu–Sn TLP bonding is employed herein because of its high remelting temperature and desirable thermal and electrical conductivities. The bonding starts with a stack of Cu–Sn–Cu metal layers that eventually transforms to Cu–Sn alloys. As the alloys have melting temperatures (Cu 3 Sn: > 600 °C, Cu 6 Sn 5 : > 400 °C) significantly higher than the process temperature, the process can be repeated without damaging previously bonded layers. A Cu–Sn TLP bonding process was developed using thin Sn metal sheets inserted between copper layers on silicon die and direct bonded copper substrates, emulating the process used to construct automotive power modules. Bond quality is characterized using (1) proof-of-concept fabrication, (2) material identification using scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis, and (3) optical analysis using optical microscopy and scanning acoustic microscope. The feasibility of multiple-sided Cu–Sn TLP bonding is demonstrated by the absence of bondline damage in multiple test samples fabricated with double- or four-sided bonding using the TLP bonding process. (paper)

Relation between the plasma characteristics and physical properties of functional zinc oxide thin film prepared by radio frequency magnetron sputtering process

International Nuclear Information System (INIS)

Hsu, Che-Wei; Cheng, Tsung-Chieh; Huang, Wen-Hsien; Wu, Jong-Shinn; Cheng, Cheng-Chih; Cheng, Kai-Wen; Huang, Shih-Chiang

2010-01-01

The ZnO thin film was deposited on a glass substrate by a RF reactive magnetron sputtering method. Results showed that plasma density, electron temperature, deposition rate and estimated ion bombardment energy increase with increasing applied RF power. Three distinct power regimes were observed, which are strongly correlated with plasma properties. In the low-power regime, the largest grain size was observed due to slow deposition rate. In the medium-power regime, the smallest grain size was found, which is attributed to insufficient time for the adatoms to migrate on substrate surface. In the high-power regime, relatively larger grain size was found due to very large ion bombardment energy which enhances the thermal migration of adatoms. Regardless of pure ZnO thin film or ZnO on glass, high transmittance (> 80%) in the visible region can be generally observed. However, the film thickness plays a more important role for controlling optical properties, especially in the UV region, than the applied RF power. In general, with properly coated ZnO thin film, we can obtain a glass substrate which is highly transparent in the visible region, is of good anti-UV characteristics, and is highly hydrophobic, which is highly suitable for applications in the glass industry.

Dielectric and acoustical high frequency characterisation of PZT thin films

International Nuclear Information System (INIS)

Conde, Janine; Muralt, Paul

2010-01-01

Pb(Zr, Ti)O 3 (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {100} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Dielectric and acoustical high frequency characterisation of PZT thin films

Science.gov (United States)

Conde, Janine; Muralt, Paul

2010-02-01

Pb(Zr, Ti)O3 (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {100} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Temperature Gradient Effect on Gas Discrimination Power of a Metal-Oxide Thin-Film Sensor Microarray

Directory of Open Access Journals (Sweden)

Joachim Goschnick

2004-05-01

Full Text Available Abstract: The paper presents results concerning the effect of spatial inhomogeneous operating temperature on the gas discrimination power of a gas-sensor microarray, with the latter based on a thin SnO2 film employed in the KAMINA electronic nose. Three different temperature distributions over the substrate are discussed: a nearly homogeneous one and two temperature gradients, equal to approx. 3.3 oC/mm and 6.7 oC/mm, applied across the sensor elements (segments of the array. The gas discrimination power of the microarray is judged by using the Mahalanobis distance in the LDA (Linear Discrimination Analysis coordinate system between the data clusters obtained by the response of the microarray to four target vapors: ethanol, acetone, propanol and ammonia. It is shown that the application of a temperature gradient increases the gas discrimination power of the microarray by up to 35 %.

High power communication satellites power systems study

Science.gov (United States)

Josloff, Allan T.; Peterson, Jerry R.

1995-01-01

This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

Fabrication and Characterisation of Flexible Coaxial Thin Thread Supercapacitors

Directory of Open Access Journals (Sweden)

Fulian Qiu

2014-08-01

Full Text Available Flexible coaxial thin thread supercapacitors were fabricated semi-automatically using a dip coating method. A typical coaxial thin thread supercapacitor of a length of 70 cm demonstrated a specific length capacitance of 0.3 mF cm-1 (11.2 mF cm-2 and 2.18 F cm-3 at 5 mV s-1, the device exhibited good electrochemical performance with a high volume energy density of 0.22 mWh cm-3 at a power density of 22 mW cm-3. Thread supercapacitors were assembled in series and parallel combinations, the accepted models for series and parallel circuit combinations were obeyed for two coaxial thread supercapacitors. The thread shows high flexibility and uniformity of specific length capacitance, one integrated with a commercial solar cell could be charged and power a LED. The process is simple, robust and easy to scale up to make unlimited length thread supercapacitors for numerous miniaturized and flexible electronic applications.

High power microwaves

CERN Document Server

Benford, James; Schamiloglu, Edl

2016-01-01

Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

Fabrication of high crystalline SnS and SnS2 thin films, and their switching device characteristics

Science.gov (United States)

Choi, Hyeongsu; Lee, Jeongsu; Shin, Seokyoon; Lee, Juhyun; Lee, Seungjin; Park, Hyunwoo; Kwon, Sejin; Lee, Namgue; Bang, Minwook; Lee, Seung-Beck; Jeon, Hyeongtag

2018-05-01

Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS2) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS2 thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS2 thin film by annealing at 450 °C for 1 h in H2S atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS2 thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 105 and 104 cm‑1 in the visible region, respectively. In addition, SnS and SnS2 thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS2 directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS2 thin films exhibited on–off drain current ratios of 8.8 and 2.1 × 103 and mobilities of 0.21 and 0.014 cm2 V‑1 s‑1, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS2 thin films were 6.0 × 1016 and 8.7 × 1013 cm‑3, respectively, in this experiment.

Exfoliated β-Ga2O3 nano-belt field-effect transistors for air-stable high power and high temperature electronics.

Science.gov (United States)

Kim, Janghyuk; Oh, Sooyeoun; Mastro, Michael A; Kim, Jihyun

2016-06-21

This study demonstrated the exfoliation of a two-dimensional (2D) β-Ga2O3 nano-belt and subsequent processing into a thin film transistor structure. This mechanical exfoliation and transfer method produces β-Ga2O3 nano-belts with a pristine surface as well as a continuous defect-free interface with the SiO2/Si substrate. This β-Ga2O3 nano-belt based transistor displayed an on/off ratio that increased from approximately 10(4) to 10(7) over the operating temperature range of 20 °C to 250 °C. No electrical breakdown was observed in our measurements up to VDS = +40 V and VGS = -60 V between 25 °C and 250 °C. Additionally, the electrical characteristics were not degraded after a month-long storage in ambient air. The demonstration of high-temperature/high-voltage operation of quasi-2D β-Ga2O3 nano-belts contrasts with traditional 2D materials such as transition metal dichalcogenides that intrinsically have limited temperature and power operational envelopes owing to their narrow bandgap. This work motivates the application of 2D β-Ga2O3 to high power nano-electronic devices for harsh environments such as high temperature chemical sensors and photodetectors as well as the miniaturization of power circuits and cooling systems in nano-electronics.

Feasibility Study of Thin Film Thermocouple Piles

Science.gov (United States)

Sisk, R. C.

2001-01-01

Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

Dielectric and acoustical high frequency characterisation of PZT thin films

Energy Technology Data Exchange (ETDEWEB)

Conde, Janine; Muralt, Paul, E-mail: janine.conde@epfl.ch [Department of Materials Science, EPFL (Switzerland)

2010-02-15

Pb(Zr, Ti)O{sub 3} (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {l_brace}100{r_brace} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Preparation and characterization of thin-film Pd–Ag supported membranes for high-temperature applications

NARCIS (Netherlands)

Fernandez Gesalaga, Ekain; Coenen, Kai; Helmi Siasi Farimani, Arash; Melendez, J.; Zuniga, Jon; Pacheco Tanaka, David Alfredo; van Sint Annaland, Martin; Gallucci, Fausto

2015-01-01

This paper reports the preparation, characterization and stability tests of thin-film Pd–Ag supported membranes for high-temperature fluidized bed membrane reactor applications. Various thin-film supported membranes have been prepared by simultaneous Pd–Ag electroless plating and have been initially

Structure and magnetic properties of highly textured nanocrystalline Mn–Zn ferrite thin film

Energy Technology Data Exchange (ETDEWEB)

Joseph, Jaison, E-mail: jaisonjosephp@gmail.com [Department of Physics, Goverment College, Khandola, Goa 403107 India (India); Tangsali, R.B. [Department of Physics, Goa University, Taleigao Plateau, Goa 403206 India (India); Pillai, V.P. Mahadevan [Department of Optoelectronics, University of Kerala,Thiruvananthapuram, Kerala 695581 India (India); Choudhary, R.J.; Phase, D.M.; Ganeshan, V. [UGC-DAE-CSR Indore, Madhya Pradesh 452017 India. (India)

2015-01-01

Nanoparticles of Mn{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} were chemically synthesized by co-precipitating the metal ions in aqueous solutions in a suitable alkaline medium. The identified XRD peaks confirm single phase spinal formation. The nanoparticle size authentication is carried out from XRD data using Debye Scherrer equation. Thin film fabricated from this nanomaterial by pulse laser deposition technique on quartz substrate was characterized using XRD and Raman spectroscopic techniques. XRD results revealed the formation of high degree of texture in the film. AFM analysis confirms nanogranular morphology and preferred directional growth. A high deposition pressure and the use of a laser plume confined to a small area for transportation of the target species created certain level of porosity in the deposited thin film. Magnetic property measurement of this highly textured nanocrystalline Mn–Zn ferrite thin film revealed enhancement in properties, which are explained on the basis of texture and surface features originated from film growth mechanism.

Transport ac loss in a rectangular thin strip with power-law E(J) relation

International Nuclear Information System (INIS)

Li, Shuo; Chen, Du-Xing; Fan, Yu; Fang, Jin

2015-01-01

Highlights: • Transport ac loss in a thin strip with power-law E(J) is systematically computed. • The scaled results can be accurately used for strips with any critical current and frequency. • Experiments may be unambiguously compared with modeling results at a critical frequency. - Abstract: Transport ac losses of a rectangular thin strip obeying relation E/E c =(J/J c ) n with a fixed critical current I c and n=5,10,20,30, and 40 are accurately computed at a fixed frequency f as functions of the current amplitude I m . The results may be interpolated and scaled to those at any values of I c ,f, and 5⩽n⩽40. Normalized in the same way as that in Norris’ analytical formula derived from the critical-state model and converting f to a critical frequency f c , the modeling results may be better compared with the Norris formula and experimental data. A complete set of calculated modeling data are given with necessary formulas to be easily used by experimentalists in any particular case

Design of robust hollow fiber membranes with high power density for osmotic energy production

KAUST Repository

Zhang, Sui

2014-04-01

This study highlights the design strategy of highly asymmetric hollow fiber membranes that possess both characteristics of high flux and high mechanical strength to effectively reap the osmotic energy from seawater brine with an ultrahigh power density. An advanced co-extrusion technology was employed to fabricate the polyethersulfone (PES) hollow fiber supports with diversified structures from macrovoid to sponge-like. The microstructure of the supports is found critical for the stability and water permeability of the thin film composite (TFC) membranes. A high porosity in the porous layer is needed to reduce internal concentration polarization, while a thick and relatively dense skin layer underneath the TFC layer is required to maintain good mechanical stability and stress dissipation. The pore size of the supporting layer underneath the TFC layer must be small with a narrow pore size distribution to ensure the formation of a less-defective, highly permeable and mechanically stable TFC layer. The newly developed hollow fiber comprising high asymmetry, high porosity, and a thick skin layer with a small and narrow pore size distribution underneath the TFC layer produces a maximum power density of 24.3W/m2 at 20.0bar by using 1M NaCl as the concentrated brine and deionized (DI) water as the feed. The proposed design strategy for ultrahigh power density membranes clearly advances the osmotic energy production close to commercialization with a quite cost-effective and practicable approach. © 2013 Elsevier B.V.

Design of robust hollow fiber membranes with high power density for osmotic energy production

KAUST Repository

Zhang, Sui; Sukitpaneenit, Panu; Chung, Neal Tai-Shung

2014-01-01

This study highlights the design strategy of highly asymmetric hollow fiber membranes that possess both characteristics of high flux and high mechanical strength to effectively reap the osmotic energy from seawater brine with an ultrahigh power density. An advanced co-extrusion technology was employed to fabricate the polyethersulfone (PES) hollow fiber supports with diversified structures from macrovoid to sponge-like. The microstructure of the supports is found critical for the stability and water permeability of the thin film composite (TFC) membranes. A high porosity in the porous layer is needed to reduce internal concentration polarization, while a thick and relatively dense skin layer underneath the TFC layer is required to maintain good mechanical stability and stress dissipation. The pore size of the supporting layer underneath the TFC layer must be small with a narrow pore size distribution to ensure the formation of a less-defective, highly permeable and mechanically stable TFC layer. The newly developed hollow fiber comprising high asymmetry, high porosity, and a thick skin layer with a small and narrow pore size distribution underneath the TFC layer produces a maximum power density of 24.3W/m2 at 20.0bar by using 1M NaCl as the concentrated brine and deionized (DI) water as the feed. The proposed design strategy for ultrahigh power density membranes clearly advances the osmotic energy production close to commercialization with a quite cost-effective and practicable approach. © 2013 Elsevier B.V.

Preparation and Analysis of Platinum Thin Films for High Temperature Sensor Applications

Science.gov (United States)

Wrbanek, John D.; Laster, Kimala L. H.

2005-01-01

A study has been made of platinum thin films for application as high temperature resistive sensors. To support NASA Glenn Research Center s high temperature thin film sensor effort, a magnetron sputtering system was installed recently in the GRC Microsystems Fabrication Clean Room Facility. Several samples of platinum films were prepared using various system parameters to establish run conditions. These films were characterized with the intended application of being used as resistive sensing elements, either for temperature or strain measurement. The resistances of several patterned sensors were monitored to document the effect of changes in parameters of deposition and annealing. The parameters were optimized for uniformity and intrinsic strain. The evaporation of platinum via oxidation during annealing over 900 C was documented, and a model for the process developed. The film adhesion was explored on films annealed to 1000 C with various bondcoats on fused quartz and alumina. From this compiled data, a list of optimal parameters and characteristics determined for patterned platinum thin films is given.

A shape-adaptive thin-film-based approach for 50% high-efficiency energy generation through micro-grating sliding electrification.

Science.gov (United States)

Zhu, Guang; Zhou, Yu Sheng; Bai, Peng; Meng, Xian Song; Jing, Qingshen; Chen, Jun; Wang, Zhong Lin

2014-06-18

Effectively harvesting ambient mechanical energy is the key for realizing self-powered and autonomous electronics, which addresses limitations of batteries and thus has tremendous applications in sensor networks, wireless devices, and wearable/implantable electronics, etc. Here, a thin-film-based micro-grating triboelectric nanogenerator (MG-TENG) is developed for high-efficiency power generation through conversion of mechanical energy. The shape-adaptive MG-TENG relies on sliding electrification between complementary micro-sized arrays of linear grating, which offers a unique and straightforward solution in harnessing energy from relative sliding motion between surfaces. Operating at a sliding velocity of 10 m/s, a MG-TENG of 60 cm(2) in overall area, 0.2 cm(3) in volume and 0.6 g in weight can deliver an average output power of 3 W (power density of 50 mW cm(-2) and 15 W cm(-3)) at an overall conversion efficiency of ∼ 50%, making it a sufficient power supply to regular electronics, such as light bulbs. The scalable and cost-effective MG-TENG is practically applicable in not only harvesting various mechanical motions but also possibly power generation at a large scale. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering

Czech Academy of Sciences Publication Activity Database

Straňák, V.; Hubička, Zdeněk; Čada, Martin; Bogdanowicz, R.; Wulff, H.; Helm, C.A.; Hippler, R.

2018-01-01

Roč. 51, č. 9 (2018), s. 1-12, č. článku 095205. ISSN 0022-3727 R&D Projects: GA ČR GA17-08389S Institutional support: RVO:68378271 Keywords : high power impulse magnetron sputtering (HiPIMS) * iron oxide thin films * wüstite * magnetite * maghemite * hematite Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics ) Impact factor: 2.588, year: 2016

High Power High Efficiency Diode Laser Stack for Processing

Science.gov (United States)

Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

2018-03-01

High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

High resolution hard X-ray photoemission using synchrotron radiation as an essential tool for characterization of thin solid films

International Nuclear Information System (INIS)

Kim, J.J.; Ikenaga, E.; Kobata, M.; Takeuchi, A.; Awaji, M.; Makino, H.; Chen, P.P.; Yamamoto, A.; Matsuoka, T.; Miwa, D.; Nishino, Y.; Yamamoto, T.; Yao, T.; Kobayashi, K.

2006-01-01

Recently, we have shown that hard X-ray photoemission spectroscopy using undulator X-rays at SPring-8 is quite feasible with both high resolution and high throughput. Here we report an application of hard X-ray photoemission spectroscopy to the characterization of electronic and chemical states of thin solid films, for which conventional PES is not applicable. As a typical example, we focus on the problem of the scatter in the reported band-gap values for InN. We show that oxygen incorporation into the InN film strongly modifies the valence and plays a crucial role in the band gap problem. The present results demonstrate the powerful applicability of high resolution photoemission spectroscopy with hard X-rays from a synchrotron source

Effects of high-temperature thermal annealing on the electronic properties of In-Ga-Zn oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Li, Qin; Song, Zhong Xiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com; Li, Yan Huai, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Ke Wei [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049, China and Department of Physics and Opt-electronic Engineering, Xi' an University of Arts and Science, Xi' an, Shaanxi 710065 (China)

2015-03-15

Indium gallium zinc oxide (IGZO) thin films were deposited by radio-frequency magnetron sputtering at room-temperature. Then, thermal annealing was conducted to improve the structural ordering. X-ray diffraction and high-resolution transmission electron microscopy demonstrated that the as-deposited IGZO thin films were amorphous and crystallization occurred at 800 and 950 °C. As a result of crystallization at high temperature, the carrier concentration and the Hall mobility of IGZO thin films were sharply increased, which could be ascribed to the increased oxygen vacancies and improved structural ordering of the thin films.

High-power AlGaN-based near-ultraviolet light-emitting diodes grown on Si(111)

Science.gov (United States)

Li, Zengcheng; Liu, Legong; Huang, Yingnan; Sun, Qian; Feng, Meixin; Zhou, Yu; Zhao, Hanmin; Yang, Hui

2017-07-01

High-power AlGaN-based 385 nm near-ultraviolet light-emitting diodes (UVA-LEDs) grown on Si(111) substrates are reported. The threading dislocation (TD) density of AlGaN was reduced by employing an Al-composition step-graded AlN/AlGaN multilayer buffer. V-shaped pits were intentionally incorporated into the active region to screen the carriers from the nonradiative recombination centers (NRCs) around the TDs and to facilitate hole injection. The light extraction efficiency was enhanced by the surface roughening of a thin-film (TF) vertical chip structure. The as-fabricated TF-UVA-LED exhibited a light output power of 960 mW at 500 mA, corresponding to an external quantum efficiency of 59.7%.

High power CW linac in PNC

International Nuclear Information System (INIS)

Toyama, S.; Wang, Y.L.; Emoto, T.

1994-01-01

Power Reactor and Nuclear Fuel Development Corporation (PNC) is developing a high power electron linac for various applications. The electron beam is accelerated in CW operation to get maximum beam current of 100 mA and energy of 10 MeV. Crucial components such as a high power L-band klystron and a high power traveling wave resonant ring (TWRR) accelerator guides were designed and manufactured and their performance were examined. These design and results from the recent high power RF tests were described in this paper. (author)

Highly stable thin film transistors using multilayer channel structure

KAUST Repository

Nayak, Pradipta K.

2015-03-09

We report highly stable gate-bias stress performance of thin film transistors (TFTs) using zinc oxide (ZnO)/hafnium oxide (HfO2) multilayer structure as the channel layer. Positive and negative gate-bias stress stability of the TFTs was measured at room temperature and at 60°C. A tremendous improvement in gate-bias stress stability was obtained in case of the TFT with multiple layers of ZnO embedded between HfO2 layers compared to the TFT with a single layer of ZnO as the semiconductor. The ultra-thin HfO2 layers act as passivation layers, which prevent the adsorption of oxygen and water molecules in the ZnO layer and hence significantly improve the gate-bias stress stability of ZnO TFTs.

A highly selective and wide range ammonia sensor—Nanostructured ZnO:Co thin film

International Nuclear Information System (INIS)

Mani, Ganesh Kumar; Rayappan, John Bosco Balaguru

2015-01-01

Graphical abstract: - Highlights: • Cobalt doped nanostructured ZnO thin films were spray deposited on glass substrates. • Co-doped ZnO film was highly selective towards ammonia than ethanol, methanol, etc. • The range of ammonia detection was improved significantly by doping cobalt in ZnO. - Abstract: Ammonia sensing characteristics of undoped and cobalt (Co)-doped nanostructured ZnO thin films were investigated. Polycrystalline nature with hexagonal wurtzite structure and high crystalline quality with dominant (0 0 2) plane orientation of Co-doped ZnO film were confirmed by the X-ray diffractogram. Scanning electron micrographs of the undoped film demonstrated the uniform deposition of sphere-shaped grains. But, smaller particles with no clear grain boundaries were observed for Co-doped ZnO thin film. Band gap values were found to be 3.26 eV and 3.22 eV for undoped and Co-doped ZnO thin films. Ammonia sensing characteristics of Co-doped ZnO film at room temperature were investigated in the concentration range of 15–1000 ppm. Variation in the sensing performances of Co-doped and pure ZnO thin films has been analyzed and compared

X-ray monochromators for high-power synchrotron radiation sources

Science.gov (United States)

Hart, Michael

1990-11-01

Exact solutions to the problems of power flow from a line source of heat into a semicylinder and of uniform heat flow normal to a flat surface are discussed. These lead to bounds on feasible designs and the boundary layer problem can be placed in proper perspective. While finite element calculations are useful if the sample boundaries are predefined, they are much less help in establishing design principles. Previous work on hot beam X-ray crystal optics has emphasised the importance of coolant hydraulics and boundary layer heat transfer. Instead this paper emphasises the importance of the elastic response of crystals to thermal strainfields and the importance of maintaining the Darwin reflectivity. The conclusions of this design study are that the diffracting crystal region should be thin, but not very thin, similar in area to the hot beam footprint, part of a thin-walked buckling crystal box and remote from the support to which the crystal is rigidly clamped. Prototype 111 and 220 cooled silicon crystals tested at the National Synchrotron Light Source at Brookhaven have almost perfect rocking curves under a beam heat load of {1}/{3}kW.

Powering the High-Luminosity Triplets

Science.gov (United States)

Ballarino, A.; Burnet, J. P.

The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

Advances in high-power, Ultrashort pulse DPSSL technologies at HiLASE

Czech Academy of Sciences Publication Activity Database

Smrž, Martin; Novák, Ondřej; Mužík, Jiří; Turčičová, Hana; Chyla, Michal; Nagisetty, Siva S.; Vyvlečka, Michal; Roškot, Lukáš; Miura, Taisuke; Černohorská, Jitka; Sikocinski, Pawel; Chen, Liyuan; Huynh, Jaroslav; Severová, Patricie; Pranovich, Alina; Endo, Akira; Mocek, Tomáš

2017-01-01

Roč. 7, č. 10 (2017), s. 1-12, č. článku 1016. ISSN 2076-3417 R&D Projects: GA MŠk LO1602; GA ČR GA16-12960S; GA MŠk LM2015086; GA TA ČR(CZ) TG02010056 EU Projects: European Commission(XE) 739573 Grant - others:OP VVV - HiLASE-CoE(XE) CZ.02.1.01/0.0/0.0/15_006/0000674 Institutional support: RVO:68378271 Keywords : diode-pumped solid- state lasers (DPSSL) * high average power lasers * higher harmonic generation * Yb:YAG * mid-infrared radiation * thin-disk laser * picosecond pulses Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.679, year: 2016

Review of Power System Stability with High Wind Power Penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Chen, Zhe

2015-01-01

analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

Science.gov (United States)

Gryglewicz, Grażyna; Śliwak, Agata; Béguin, François

2013-08-01

A hybrid electrode material for high-power supercapacitors was fabricated by grafting carbon nanofibers (CNFs) onto the surface of powdered activated carbon (AC) through catalytic chemical vapor deposition (CCVD). A uniform thin layer of disentangled CNFs with a herringbone structure was deposited on the carbon surface through the decomposition of propane at 450 °C over an AC-supported nickel catalyst. CNF coating was controlled by the reaction time and the nickel content. The superior CNF/AC composite displays excellent electrochemical performance in a 0.5 mol L(-1) solution of K2 SO4 due to its unique structure. At a high scan rate (100 mV s(-1) ) and current loading (20 A g(-1) ), the capacitance values were three- and fourfold higher than those for classical AC/carbon black composites. Owing to this feature, a high energy of 10 Wh kg(-1) was obtained over a wide power range in neutral medium at a voltage of 0.8 V. The significant enhancement of charge propagation is attributed to the presence of herringbone CNFs, which facilitate the diffusion of ions in the electrode and play the role of electronic bridges between AC particles. An in situ coating of AC with short CNFs (below 200 nm) is a very attractive method for producing the next generation of carbon composite materials with a high power performance in supercapacitors working in neutral medium. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research and development of photovoltaic power system. Development of novel technologies for fabrication of high quality silicon thin films for solar cells; Taiyoko hatsuden system no kenkyu kaihatsu. Kohinshitsu silicon usumaku sakusei gijutsu

Energy Technology Data Exchange (ETDEWEB)

Shimizu, T [Kanazawa University, Ishikawa (Japan). Faculty of Engineering

1994-12-01

Described herein are the results of the FY1994 research program for development of novel technologies for fabrication of high quality thin films of silicon for solar cells. The study on the mechanisms and effects of chemical annealing reveals that the film structure greatly varies depending on substrate temperature during the hydrotreatment process, based on the tests with substrate temperature, deposition of superthin film (T1) and hydrotreatment (T2) as the variable parameters. Chemical annealing at low temperature produces a high-quality a-Si:H film of low defect content. The study on fabrication of thin polycrystalline silicon films at low temperature observes on real time the process of deposition of the thin films on polycrystalline silicon substrates, where a natural oxide film is removed beforehand from the substrate. The results indicate that a thin polycrystalline silicon film of 100% crystallinity can be formed even on a polycrystalline silicon substrate by controlling starting gas composition and substrate temperature. The layer-by-layer method is used as the means for forming the seed crystals on a glass substrate, where deposition and hydrotreatment are repeated alternately, to produce the thin crystalline silicon films of high crystallinity. 3 figs.

Autonomously managed high power systems

International Nuclear Information System (INIS)

Weeks, D.J.; Bechtel, R.T.

1985-01-01

The need for autonomous power management capabilities will increase as the power levels of spacecraft increase into the multi-100 kW range. The quantity of labor intensive ground and crew support consumed by the 9 kW Skylab cannot be afforded in support of a 75-300 kW Space Station or high power earth orbital and interplanetary spacecraft. Marshall Space Flight Center is managing a program to develop necessary technologies for high power system autonomous management. To date a reference electrical power system and automation approaches have been defined. A test facility for evaluation and verification of management algorithms and hardware has been designed with the first of the three power channel capability nearing completion

ICAN: High power neutral beam generation

International Nuclear Information System (INIS)

Moustaizis, S.D.; Lalousis, P.; Perrakis, K.; Auvray, P.; Larour, J.; Ducret, J.E.; Balcou, P.

2015-01-01

During the last few years there is an increasing interest on the development of alternative high power new negative ion source for Tokamak applications. The proposed new neutral beam device presents a number of advantages with respect to: the density current, the acceleration voltage, the relative compact dimension of the negative ion source, and the coupling of a high power laser beam for photo-neutralization of the negative ion beam. Here we numerically investigate, using a multi- fluid 1-D code, the acceleration and the extraction of high power ion beam from a Magnetically Insulated Diode (MID). The diode configuration will be coupled to a high power device capable of extracting a current up to a few kA with an accelerating voltage up to MeV. An efficiency of up to 92% of the coupling of the laser beam, is required in order to obtain a high power, up to GW, neutral beam. The new high energy, high average power, high efficiency (up to 30%) ICAN fiber laser is proposed for both the plasma generation and the photo-neutralizer configuration. (authors)

Atomic layer deposition of copper thin film and feasibility of deposition on inner walls of waveguides

Science.gov (United States)

Yuqing, XIONG; Hengjiao, GAO; Ni, REN; Zhongwei, LIU

2018-03-01

Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature, using copper(I)-N,N‧-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas. The influence of temperature, plasma power, mode of plasma, and pulse time, on the deposition rate of copper thin film, the purity of the film and the step coverage were studied. The feasibility of copper film deposition on the inner wall of a carbon fibre reinforced plastic waveguide with high aspect ratio was also studied. The morphology and composition of the thin film were studied by atomic force microscopy and x-ray photoelectron spectroscopy, respectively. The square resistance of the thin film was also tested by a four-probe technique. On the basis of on-line diagnosis, a growth mechanism of copper thin film was put forward, and it was considered that surface functional group played an important role in the process of nucleation and in determining the properties of thin films. A high density of plasma and high free-radical content were helpful for the deposition of copper thin films.

On the Nature and Extent of Optically Thin Marine low Clouds

Science.gov (United States)

Leahy, L. V.; Wood, R.; Charlson, R. J.; Hostetler, C. A.; Rogers, R. R.; Vaughan, M. A.; Winker, D. M.

2012-01-01

Macrophysical properties of optically thin marine low clouds over the nonpolar oceans (60 deg S-60 deg N) are measured using 2 years of full-resolution nighttime data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Optically thin clouds, defined as the subset of marine low clouds that do not fully attenuate the lidar signal, comprise almost half of the low clouds over the marine domain. Regionally, the fraction of low clouds that are optically thin (f(sub thin,cld)) exhibits a strong inverse relationship with the low-cloud cover, with maxima in the tropical trades (f(sub thin,cld) greater than 0.8) and minima in regions of persistent marine stratocumulus and in midlatitudes (f(sub thin,cld) less than 0.3). Domain-wide, a power law fit describes the cloud length distribution, with exponent beta = 2.03 +/- 0.06 (+/-95% confidence interval). On average, the fraction of a cloud that is optically thin decreases from approximately 1 for clouds smaller than 2 km to less than 0.3 for clouds larger than 30 km. This relationship is found to be independent of region, so that geographical variations in the cloud length distribution explain three quarters of the variance in f(sub thin,cld). Comparing collocated trade cumulus observations from CALIOP and the airborne High Spectral Resolution Lidar reveals that clouds with lengths smaller than are resolvable with CALIOP contribute approximately half of the low clouds in the region sampled. A bounded cascade model is constructed to match the observations from the trades. The model shows that the observed optically thin cloud behavior is consistent with a power law scaling of cloud optical depth and suggests that most optically thin clouds only partially fill the CALIOP footprint.

Investigation of the Optoelectronic Properties of Ti-doped Indium Tin Oxide Thin Film.

Science.gov (United States)

Pu, Nen-Wen; Liu, Wei-Sheng; Cheng, Huai-Ming; Hu, Hung-Chun; Hsieh, Wei-Ting; Yu, Hau-Wei; Liang, Shih-Chang

2015-09-21

: In this study, direct-current magnetron sputtering was used to fabricate Ti-doped indium tin oxide (ITO) thin films. The sputtering power during the 350-nm-thick thin-film production process was fixed at 100 W with substrate temperatures increasing from room temperature to 500 °C. The Ti-doped ITO thin films exhibited superior thin-film resistivity (1.5 × 10 - ⁴ Ω/cm), carrier concentration (4.1 × 10 21 cm - ³), carrier mobility (10 cm²/Vs), and mean visible-light transmittance (90%) at wavelengths of 400-800 nm at a deposition temperature of 400 °C. The superior carrier concentration of the Ti-doped ITO alloys (>10 21 cm - ³) with a high figure of merit (81.1 × 10 - ³ Ω - ¹) demonstrate the pronounced contribution of Ti doping, indicating their high suitability for application in optoelectronic devices.

High average power supercontinuum sources

Indian Academy of Sciences (India)

The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium.

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

2018-01-01

. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage upto 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wideband gap semiconductor devices of GaN switches and SiC diodes are combined...... to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated halfbridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved......State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable...

Operating method of amorphous thin film semiconductor element

Energy Technology Data Exchange (ETDEWEB)

Mori, Koshiro; Ono, Masaharu; Hanabusa, Akira; Osawa, Michio; Arita, Takashi

1988-05-31

The existing technologies concerning amorphous thin film semiconductor elements are the technologies concerning the formation of either a thin film transistor or an amorphous Si solar cell on a substrate. In order to drive a thin film transistor for electronic equipment control by the output power of an amorphous Si solar cell, it has been obliged to drive the transistor weth an amorphous solar cell which was formed on a substrate different from that for the transistor. Accordingly, the space for the amorphous solar cell, which was formed on the different substrate, was additionally needed on the substrate for the thin film transistor. In order to solve the above problem, this invention proposes an operating method of an amorphous thin film semiconductor element that after forming an amorphous Si solar cell through lamination on the insulation coating film which covers the thin film transistor formed on the substrate, the thin film transistor is driven by the output power of this solar cell. The invention eliminates the above superfluous space and reduces the size of the amorphous thin film semiconductor element including the electric source. (3 figs)

Fault analysis and strategy of high pulsed power supply for high power laser

International Nuclear Information System (INIS)

Liu Kefu; Qin Shihong; Li Jin; Pan Yuan; Yao Zonggan; Zheng Wanguo; Guo Liangfu; Zhou Peizhang; Li Yizheng; Chen Dehuai

2001-01-01

according to the requirements of driving flash-lamp, a high pulsed power supply (PPS) based on capacitors as energy storage elements is designed. The author analyzes in detail the faults of high pulsed power supply for high power laser. Such as capacitor internal short-circuit, main bus breakdown to ground, flashlamp sudden short or break. The fault current and voltage waveforms were given by circuit simulations. Based on the analysis and computation, the protection strategy with the fast fuse and ZnO was put forward, which can reduce the damage of PPS to the lower extent and provide the personnel safe and collateral property from the all threats. The preliminary experiments demonstrated that the design of the PPS can satisfy the project requirements

Performance improvement for solution-processed high-mobility ZnO thin-film transistors

International Nuclear Information System (INIS)

Li Chensha; Loutfy, Rafik O; Li Yuning; Wu Yiliang; Ong, Beng S

2008-01-01

The fabrication technology of stable, non-toxic, transparent, high performance zinc oxide (ZnO) thin-film semiconductors via the solution process was investigated. Two methods, which were, respectively, annealing a spin-coated precursor solution and annealing a drop-coated precursor solution, were compared. The prepared ZnO thin-film semiconductor transistors have well-controlled, preferential crystal orientation and exhibit superior field-effect performance characteristics. But the ZnO thin-film transistor (TFT) fabricated by annealing a drop-coated precursor solution has a distinctly elevated linear mobility, which further approaches the saturated mobility, compared with that fabricated by annealing a spin-coated precursor solution. The performance of the solution-processed ZnO TFT was further improved when substituting the spin-coating process by the drop-coating process

Performance improvement for solution-processed high-mobility ZnO thin-film transistors

Energy Technology Data Exchange (ETDEWEB)

Li Chensha; Loutfy, Rafik O [Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Li Yuning; Wu Yiliang; Ong, Beng S [Materials Design and Integration Laboratory, Xerox Research Centre of Canada, 2660 Speakman Drive, Mississauga, Ontario L5K 2L1 (Canada)], E-mail: lichnsa@163.com

2008-06-21

The fabrication technology of stable, non-toxic, transparent, high performance zinc oxide (ZnO) thin-film semiconductors via the solution process was investigated. Two methods, which were, respectively, annealing a spin-coated precursor solution and annealing a drop-coated precursor solution, were compared. The prepared ZnO thin-film semiconductor transistors have well-controlled, preferential crystal orientation and exhibit superior field-effect performance characteristics. But the ZnO thin-film transistor (TFT) fabricated by annealing a drop-coated precursor solution has a distinctly elevated linear mobility, which further approaches the saturated mobility, compared with that fabricated by annealing a spin-coated precursor solution. The performance of the solution-processed ZnO TFT was further improved when substituting the spin-coating process by the drop-coating process.

High Power Density Power Electronic Converters for Large Wind Turbines

DEFF Research Database (Denmark)

Senturk, Osman Selcuk

. For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability......In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability...

A high-power versatile wireless power transfer for biomedical implants.

Science.gov (United States)

Jiang, Hao; Zhang, Jun Min; Liou, Shy Shenq; Fechter, Richard; Hirose, Shinjiro; Harrison, Michael; Roy, Shuvo

2010-01-01

Implantable biomedical actuators are highly desired in modern medicine. However, how to power up these biomedical implants remains a challenge since most of them need more than several hundreds mW of power. The air-core based radio-frequency transformer (two face-to-face inductive coils) has been the only non-toxic and non-invasive power source for implants for the last three decades [1]. For various technical constraints, the maximum delivered power is limited by this approach. The highest delivered power reported is 275 mW over 1 cm distance [2]. Also, the delivered power is highly vulnerable to the coils' geometrical arrangement and the electrical property of the medium around them. In this paper, a novel rotating-magnets based wireless power transfer that can deliver ∼10 W over 1 cm is demonstrated. The delivered power is significantly higher than the existing start-of-art. Further, the new method is versatile since there is no need to have the impedance matching networks that are highly susceptible to the operating frequency, the coil arrangement and the environment.

Highly Yb-doped KGd(WO4)2 thin-film amplifier

NARCIS (Netherlands)

Yong, Yean Sheng; Aravazhi, S.; Vázquez-Córdova, Sergio Andrés; García Blanco, Sonia Maria; Pollnau, Markus

We report record-high small-signal gain of 1050 dB/cm at 981 nm wavelength in a KGd0.425Yb0.575(WO4)2 thin film. The sensitivity of gain to the shift of beam-focus position, which is critical under non-waveguiding conditions, is investigated.

probing the atmosphere with high power, high resolution radars

Science.gov (United States)

Hardy, K. R.; Katz, I.

1969-01-01

Observations of radar echoes from the clear atmosphere are presented and the scattering mechanisms responsible for the two basic types of clear-air echoes are discussed. The commonly observed dot echo originates from a point in space and usually shows little variation in echo intensity over periods of about 0.1 second. The second type of clear-air radar echo appears diffuse in space, and signal intensities vary considerably over periods of less than 0.1 second. The echoes often occur in thin horizontal layers or as boundaries of convective activity; these are characterized by sharp gradients of refractive index. Some features of clear-air atmospheric structures as observed with radar are presented. These structures include thin stable inversions, convective thermals, Benard convection cells, breaking gravity waves, and high tropospheric layers which are sufficiently turbulent to affect aircraft.

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

Science.gov (United States)

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

2015-10-01

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

Porous Zinc Oxide Thin Films: Synthesis Approaches and Applications

Directory of Open Access Journals (Sweden)

Marco Laurenti

2018-02-01

Full Text Available Zinc oxide (ZnO thin films have been widely investigated due to their multifunctional properties, i.e., catalytic, semiconducting and optical. They have found practical use in a wide number of application fields. However, the presence of a compact micro/nanostructure has often limited the resulting material properties. Moreover, with the advent of low-dimensional ZnO nanostructures featuring unique physical and chemical properties, the interest in studying ZnO thin films diminished more and more. Therefore, the possibility to combine at the same time the advantages of thin-film based synthesis technologies together with a high surface area and a porous structure might represent a powerful solution to prepare ZnO thin films with unprecedented physical and chemical characteristics that may find use in novel application fields. Within this scope, this review offers an overview on the most successful synthesis methods that are able to produce ZnO thin films with both framework and textural porosities. Moreover, we discuss the related applications, mainly focused on photocatalytic degradation of dyes, gas sensor fabrication and photoanodes for dye-sensitized solar cells.

Self-powered neutron detector

International Nuclear Information System (INIS)

Goldstein, N.P.; Todt, W.H.

1976-01-01

A self-powered neutron detector is detailed wherein a thin conductive layer of low neutron cross section, high density material is disposed about an emitter core of material which spontaneously emits radiation on neutron capture. The high density material is absorptive of beta radiation emitted by decay of the emitter core activation product, but is substantially transmissive to the high average energy prompt electrons emitted by the emitter core material. (author)

High temperature polymer film dielectrics for aerospace power conditioning capacitor applications

Energy Technology Data Exchange (ETDEWEB)

Venkat, Narayanan, E-mail: venkats3@gmail.co [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); Dang, Thuy D. [Air Force Research Laboratory-Nanostructured and Biological Materials Branch (AFRL/RXBN) (United States); Bai Zongwu; McNier, Victor K. [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); DeCerbo, Jennifer N. [Air Force Research Laboratory-Electrical Technology Branch (AFRL/RZPE), Wright-Patterson Air Force Base, OH 45433 (United States); Tsao, B.-H. [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); Stricker, Jeffery T. [Air Force Research Laboratory-Electrical Technology Branch (AFRL/RZPE), Wright-Patterson Air Force Base, OH 45433 (United States)

2010-04-15

Polymer dielectrics are the preferred materials of choice for capacitive energy-storage applications because of their potential for high dielectric breakdown strengths, low dissipation factors and good dielectric stability over a wide range of frequencies and temperatures, despite having inherently lower dielectric constants relative to ceramic dielectrics. They are also amenable to large area processing into films at a relatively lower cost. Air Force currently has a strong need for the development of compact capacitors which are thermally robust for operation in a variety of aerospace power conditioning applications. While such applications typically use polycarbonate (PC) dielectric films in wound capacitors for operation from -55 deg. C to 125 deg. C, future power electronic systems would require the use of polymer dielectrics that can reliably operate up to elevated temperatures in the range of 250-350 deg. C. The focus of this research is the generation and dielectric evaluation of metallized, thin free-standing films derived from high temperature polymer structures such as fluorinated polybenzoxazoles, post-functionalized fluorinated polyimides and fluorenyl polyesters incorporating diamond-like hydrocarbon units. The discussion is centered mainly on variable temperature dielectric measurements of film capacitance and dissipation factor and the effects of thermal cycling, up to a maximum temperature of 350 deg. C, on film dielectric performance. Initial studies clearly point to the dielectric stability of these films for high temperature power conditioning applications, as indicated by their relatively low temperature coefficient of capacitance (TCC) (approx2%) over the entire range of temperatures. Some of the films were also found to exhibit good dielectric breakdown strengths (up to 470 V/mum) and a film dissipation factor of the order of <0.003 (0.3%) at the frequency of interest (10 kHz) for the intended applications. The measured relative dielectric

Influence of annealing on texture properties of cerium oxide thin films

International Nuclear Information System (INIS)

Arunkumar, P.; Suresh Babu, K.; Ramaseshan, R.; Dash, S.

2013-01-01

Future power demand needs an energy source with higher efficiency, better power density, clean energy and fuel flexibility. Solid oxide fuel cell (SOFC) is one of the potential sources for future needs. Though the polymer and direct methanol based electrolyte are much suitable, for versatile applications (portable devices) they are having major challenges such as design, platinum based catalyst, lower power density and fuel flexibility (free from hydrocarbons). However, in SOFC the high operating temperature is the only major issue. Operating temperature of SOFC could be reduced by proper selection of electrolyte material which should have minimum ionic conductivity of 0.1 Scm -1 at reduced activation energy. This can be achieved by thin film based doped cerium oxide electrolyte for SOFC, leads to Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC). In the present work, we focus on the synthesis of cerium oxide and 20 mol % samarium doped cerium oxide (SDC) nanoparticles by co-precipitation method and to synthesis thin films of the same. Pellets of those powders were heat treated at different temperatures and used as targets for e-beam evaporation to fabricate thin film based electrolyte. Stoichiometry of both powders and thin films were confirmed by XRF and EPMA. GIXRD profiles of ceria and SDC thin films are shown below and a preferred orientation effect is observed in SDC films. In SDC films the X-ray peaks have a shift towards lower angles, due to the difference in ionic radii of Ce 4+ and Sm 3+ . The band gap of CeO 2 (2.88 eV) from optical absorption technique indicates the presence of Ce 3+ with Ce 4+ , indirectly shows the concentration of oxygen vacancies which is required for the thin film electrolyte

Highly Hydrophilic Thin-Film Composite Forward Osmosis Membranes Functionalized with Surface-Tailored Nanoparticles

KAUST Repository

Tiraferri, Alberto; Kang, Yan; Giannelis, Emmanuel P.; Elimelech, Menachem

2012-01-01

Thin-film composite polyamide membranes are state-of-the-art materials for membrane-based water purification and desalination processes, which require both high rejection of contaminants and high water permeabilities. However, these membranes

Pulsed high-power beams

International Nuclear Information System (INIS)

Reginato, L.L.; Birx, D.L.

1988-01-01

The marriage of induction linac technology with nonlinear magnetic modulators has produced some unique capabilities. It is now possible to produce short-pulse electron beams with average currents measured in amperes, at gradients approaching 1-MeV/m, and with power efficiencies exceeding 50%. This paper reports on a 70-MeV, 3-kA induction accelerator (ETA II) constructed at the Lawrence Livermore National Laboratory that incorporates the pulse technology concepts that have evolved over the past several years. The ETA II is a linear induction accelerator and provides a test facility for demonstration of the high-average-power components and high-brightness sources used in such accelerators. The pulse drive of the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak-power capability, repetition rates exceeding 1 kHz, and excellent reliability

High power RF test of an 805 MHz RF cavity for a muon cooling channel

International Nuclear Information System (INIS)

Li, Derun; Corlett, J.; MacGill, R.; Rimmer, R.; Wallig, J.; Zisman, M.; Moretti, A.; Qian, Z.; Wu, V.; Summers, D.; Norem, J.

2002-01-01

We present recent high power RF test results on an 805 MHz cavity for a muon cooling experiment at Lab G in Fermilab. In order to achieve high accelerating gradient for large transverse emittance muon beams, the cavity design has adopted a pillbox like shape with 16 cm diameter beam iris covered by thin Be windows, which are demountable to allow for RF tests of different windows. The cavity body is made from copper with stiff stainless steel rings brazed to the cavity body for window attachments. View ports and RF probes are available for visual inspections of the surface of windows and cavity and measurement of the field gradient. Maximum of three thermo-couples can be attached to the windows for monitoring the temperature gradient on the windows caused by RF heating. The cavity was measured to have Q 0 of about 15,000 with copper windows and coupling constant of 1.3 before final assembling. A 12 MW peak power klystron is available at Lab G in Fermilab for the high power test. The cavity and coupler designs were performed using the MAFIA code in the frequency and the time domain. Numerical simulation results and cold test measurements on the cavity and coupler will be presented for comparisons

A battery-powered high-current power supply for superconductors

CERN Document Server

Wake, M; Suda, K

2002-01-01

Since superconductors do not require voltages, a high-current power supply could run with low power if the voltage is sufficiently reduced. Even a battery-powered power supply could give as much as 2,000A for a superconductor. To demonstrate this hypothesis, a battery-powered 2,000A power supply was constructed. It uses an IGBT chopper and Schottky diode together with a specially arranged transformer to produce a high current with low voltage. Testing of 2,000A operation was performed for about 1.5 hr using 10 car batteries. Charging time for this operation was 8 hr. Ramping control was smooth and caused no trouble. Although the IGBT frequency ripple of 16.6 kHz was easily removed using a passive filter, spike noise remained in the output voltage. This ripple did not cause any trouble in operating a pancake-type inductive superconducting load. (author)

High-field, high-density tokamak power reactor

International Nuclear Information System (INIS)

Cohn, D.R.; Cook, D.L.; Hay, R.D.; Kaplan, D.; Kreischer, K.; Lidskii, L.M.; Stephany, W.; Williams, J.E.C.; Jassby, D.L.; Okabayashi, M.

1977-11-01

A conceptual design of a compact (R 0 = 6.0 m) high power density (average P/sub f/ = 7.7 MW/m 3 ) tokamak demonstration power reactor has been developed. High magnetic field (B/sub t/ = 7.4 T) and moderate elongation (b/a = 1.6) permit operation at the high density (n(0) approximately 5 x 10 14 cm -3 ) needed for ignition in a relatively small plasma, with a spatially-averaged toroidal beta of only 4%. A unique design for the Nb 3 Sn toroidal-field magnet system reduces the stress in the high-field trunk region, and allows modularization for simpler disassembly. The modest value of toroidal beta permits a simple, modularized plasma-shaping coil system, located inside the TF coil trunk. Heating of the dense central plasma is attained by the use of ripple-assisted injection of 120-keV D 0 beams. The ripple-coil system also affords dynamic control of the plasma temperature during the burn period. A FLIBE-lithium blanket is designed especially for high-power-density operation in a high-field environment, and gives an overall tritium breeding ratio of 1.05 in the slowly pumped lithium

The origin of local strain in highly epitaxial oxide thin films.

Science.gov (United States)

Ma, Chunrui; Liu, Ming; Chen, Chonglin; Lin, Yuan; Li, Yanrong; Horwitz, J S; Jiang, Jiechao; Meletis, E I; Zhang, Qingyu

2013-10-31

The ability to control the microstructures and physical properties of hetero-epitaxial functional oxide thin films and artificial structures is a long-sought goal in functional materials research. Normally, only the lattice misfit between the film and the substrate is considered to govern the physical properties of the epitaxial films. In fact, the mismatch of film unit cell arrangement and the Surface-Step-Terrace (SST) dimension of the substrate, named as "SST residual matching", is another key factor that significantly influence the properties of the epitaxial film. The nature of strong local strain induced from both lattice mismatch and the SST residual matching on ferroelectric (Ba,Sr)TiO3 and ferromagnetic (La,Ca)MnO3 thin films are systematically investigated and it is demonstrated that this combined effect has a dramatic impact on the physical properties of highly epitaxial oxide thin films. A giant anomalous magnetoresistance effect (~10(10)) was achieved from the as-designed vicinal surfaces.

Thin seam mining

Energy Technology Data Exchange (ETDEWEB)

Sikora, W [Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1989-06-01

Discusses thin seam mining in Poland and its prospects. There were 194 working faces in coal seams to 1.5 m thick in Poland in 1988. Of them, 115 fell on faces with powered supports, 79 on faces with SHC-40 and Valent props; 108 shearer loaders and 45 coal plows were used for longwall mining of thin coal seams. Drilling and blasting was used to mine 21 working faces. Longwall faces in seams to 1.0 m thick gave 2.0% coal output, faces in coal seams 1.01-1.5 m thick gave 12.2% of daily coal output of underground mining. Structure of daily coal output of faces in thin seams was the following: 52 faces below 300 t/day, 42 from 301-500 t/day, 63 from 501 to 1,000 t/day, 17 faces above 1,000 t/day. Prospects for increasing coal output of faces in thin seams are discussed. 7 refs.

Technology breakthroughs in high performance metal-oxide-semiconductor devices for ultra-high density, low power non-volatile memory applications

Science.gov (United States)

Hong, Augustin Jinwoo

Non-volatile memory devices have attracted much attention because data can be retained without power consumption more than a decade. Therefore, non-volatile memory devices are essential to mobile electronic applications. Among state of the art non-volatile memory devices, NAND flash memory has earned the highest attention because of its ultra-high scalability and therefore its ultra-high storage capacity. However, human desire as well as market competition requires not only larger storage capacity but also lower power consumption for longer battery life time. One way to meet this human desire and extend the benefits of NAND flash memory is finding out new materials for storage layer inside the flash memory, which is called floating gate in the state of the art flash memory device. In this dissertation, we study new materials for the floating gate that can lower down the power consumption and increase the storage capacity at the same time. To this end, we employ various materials such as metal nanodot, metal thin film and graphene incorporating complementary-metal-oxide-semiconductor (CMOS) compatible processes. Experimental results show excellent memory effects at relatively low operating voltages. Detailed physics and analysis on experimental results are discussed. These new materials for data storage can be promising candidates for future non-volatile memory application beyond the state of the art flash technologies.

Investigation of the Optoelectronic Properties of Ti-doped Indium Tin Oxide Thin Film

Directory of Open Access Journals (Sweden)

Nen-Wen Pu

2015-09-01

Full Text Available : In this study, direct-current magnetron sputtering was used to fabricate Ti-doped indium tin oxide (ITO thin films. The sputtering power during the 350-nm-thick thin-film production process was fixed at 100 W with substrate temperatures increasing from room temperature to 500 °C. The Ti-doped ITO thin films exhibited superior thin-film resistivity (1.5 × 10−4 Ω/cm, carrier concentration (4.1 × 1021 cm−3, carrier mobility (10 cm2/Vs, and mean visible-light transmittance (90% at wavelengths of 400–800 nm at a deposition temperature of 400 °C. The superior carrier concentration of the Ti-doped ITO alloys (>1021 cm−3 with a high figure of merit (81.1 × 10−3 Ω−1 demonstrate the pronounced contribution of Ti doping, indicating their high suitability for application in optoelectronic devices.

Modeling of a diode-pumped thin-disk cesium vapor laser

Science.gov (United States)

An, Guofei; Cai, He; Liu, Xiaoxu; Han, Juhong; Zhang, Wei; Wang, Hongyuan; Wang, You

2018-03-01

A diode pumped alkali laser (DPAL) provides a significant potential for construction of high-powered lasers. Until now, a series of models have been established to analyze the kinetic process and most of them are based on the end-pumped alkali laser system in which the vapor cell are usually cylindrical and cuboid. In this paper, a mathematic model is constructed to investigate the kinetic processes of a diode pumped thin-disk cesium vapor laser, in which the cesium vapor and the buffer gases are beforehand filled in a sealed glass cell with a thin-disk structure. We systemically study the influences of the cell temperature and cell thickness on the output features of a thin-disk DPAL. Further, we study the thin-disk DPAL with the W-shaped resonator and multiple-disk configuration. To the best of our knowledge, there have not been any similar reports so far.

High-Resolution Spin-on-Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array.

Science.gov (United States)

Lee, Woongchan; Lee, Jongha; Yun, Huiwon; Kim, Joonsoo; Park, Jinhong; Choi, Changsoon; Kim, Dong Chan; Seo, Hyunseon; Lee, Hakyong; Yu, Ji Woong; Lee, Won Bo; Kim, Dae-Hyeong

2017-10-01

Inorganic-organic hybrid perovskite thin films have attracted significant attention as an alternative to silicon in photon-absorbing devices mainly because of their superb optoelectronic properties. However, high-definition patterning of perovskite thin films, which is important for fabrication of the image sensor array, is hardly accomplished owing to their extreme instability in general photolithographic solvents. Here, a novel patterning process for perovskite thin films is described: the high-resolution spin-on-patterning (SoP) process. This fast and facile process is compatible with a variety of spin-coated perovskite materials and perovskite deposition techniques. The SoP process is successfully applied to develop a high-performance, ultrathin, and deformable perovskite-on-silicon multiplexed image sensor array, paving the road toward next-generation image sensor arrays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alloy-dependent deformation behavior of highly ductile nanocrystalline AuCu thin films

International Nuclear Information System (INIS)

Lohmiller, Jochen; Spolenak, Ralph; Gruber, Patric A.

2014-01-01

Nanocrystalline thin films on compliant substrates become increasingly important for the development of flexible electronic devices. In this study, nanocrystalline AuCu thin films on polyimide substrate were tested in tension while using a synchrotron-based in situ testing technique. Analysis of X-ray diffraction profiles allowed identifying the underlying deformation mechanisms. Initially, elastic and microplastic deformation is observed, followed by dislocation-mediated shear band formation, and eventually macroscopic crack formation. Particularly the influence of alloy composition, heat-treatment, and test temperature were investigated. Generally, a highly ductile behavior is observed. However, high Cu concentrations, annealing, and/or large plastic strains lead to localized deformation and hence reduced ductility. On the other hand, enhanced test temperature allows for a delocalized deformation and extended ductility

Alloy-dependent deformation behavior of highly ductile nanocrystalline AuCu thin films

Energy Technology Data Exchange (ETDEWEB)

Lohmiller, Jochen [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, 76021 Karlsruhe (Germany); Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Spolenak, Ralph [Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Gruber, Patric A., E-mail: patric.gruber@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, 76021 Karlsruhe (Germany)

2014-02-10

Nanocrystalline thin films on compliant substrates become increasingly important for the development of flexible electronic devices. In this study, nanocrystalline AuCu thin films on polyimide substrate were tested in tension while using a synchrotron-based in situ testing technique. Analysis of X-ray diffraction profiles allowed identifying the underlying deformation mechanisms. Initially, elastic and microplastic deformation is observed, followed by dislocation-mediated shear band formation, and eventually macroscopic crack formation. Particularly the influence of alloy composition, heat-treatment, and test temperature were investigated. Generally, a highly ductile behavior is observed. However, high Cu concentrations, annealing, and/or large plastic strains lead to localized deformation and hence reduced ductility. On the other hand, enhanced test temperature allows for a delocalized deformation and extended ductility.

Applications of high power microwaves

International Nuclear Information System (INIS)

Benford, J.; Swegle, J.

1993-01-01

The authors address a number of applications for HPM technology. There is a strong symbiotic relationship between a developing technology and its emerging applications. New technologies can generate new applications. Conversely, applications can demand development of new technological capability. High-power microwave generating systems come with size and weight penalties and problems associated with the x-radiation and collection of the electron beam. Acceptance of these difficulties requires the identification of a set of applications for which high-power operation is either demanded or results in significant improvements in peRFormance. The authors identify the following applications, and discuss their requirements and operational issues: (1) High-energy RF acceleration; (2) Atmospheric modification (both to produce artificial ionospheric mirrors for radio waves and to save the ozone layer); (3) Radar; (4) Electronic warfare; and (5) Laser pumping. In addition, they discuss several applications requiring high average power than border on HPM, power beaming and plasma heating

Quantifying resistances across nanoscale low- and high-angle interspherulite boundaries in solution-processed organic semiconductor thin films.

Science.gov (United States)

Lee, Stephanie S; Mativetsky, Jeffrey M; Loth, Marsha A; Anthony, John E; Loo, Yueh-Lin

2012-11-27

The nanoscale boundaries formed when neighboring spherulites impinge in polycrystalline, solution-processed organic semiconductor thin films act as bottlenecks to charge transport, significantly reducing organic thin-film transistor mobility in devices comprising spherulitic thin films as the active layers. These interspherulite boundaries (ISBs) are structurally complex, with varying angles of molecular orientation mismatch along their lengths. We have successfully engineered exclusively low- and exclusively high-angle ISBs to elucidate how the angle of molecular orientation mismatch at ISBs affects their resistivities in triethylsilylethynyl anthradithiophene thin films. Conductive AFM and four-probe measurements reveal that current flow is unaffected by the presence of low-angle ISBs, whereas current flow is significantly disrupted across high-angle ISBs. In the latter case, we estimate the resistivity to be 22 MΩμm(2)/width of the ISB, only less than a quarter of the resistivity measured across low-angle grain boundaries in thermally evaporated sexithiophene thin films. This discrepancy in resistivities across ISBs in solution-processed organic semiconductor thin films and grain boundaries in thermally evaporated organic semiconductor thin films likely arises from inherent differences in the nature of film formation in the respective systems.

Thermoelectric power of Bi and Bi{sub 1{minus}x}Sb{sub x} alloy thin films and superlattices grown by MBE

Energy Technology Data Exchange (ETDEWEB)

Cho, S; DiVenere, A; Wong, G K; Ketterson, J B; Meyer, J R; Hoffman, C A

1997-07-01

The authors have measured the thermoelectric power (TEP) of MBE-grown epitaxial Bi and Bi{sub 1{minus}x} alloy thin films and superlattices as a function of temperature in the range 20--300 K. They have observed that the TEP of a Bi thin film of 1 {micro}m thickness is in good agreement with the bulk single crystal value and that the TEPs for superlattices with 400 {angstrom} and 800 {angstrom} Bi well thicknesses are enhanced over the bulk values. For x = 0.072 and 0.088 in Bi{sub 1{minus}x}Sb{sub x} thin films showing semiconducting behavior, TEP enhancement was observed by a factor of two. However as Bi or Bi{sub 1{minus}x}Sb{sub x} well thickness decreases in superlattice geometry, the TEP decreases, which may be due to unintentional p-type doping.

Compositional ratio effect on the surface characteristics of CuZn thin films

Science.gov (United States)

Choi, Ahrom; Park, Juyun; Kang, Yujin; Lee, Seokhee; Kang, Yong-Cheol

2018-05-01

CuZn thin films were fabricated by RF co-sputtering method on p-type Si(100) wafer with various RF powers applied on metallic Cu and Zn targets. This paper aimed to determine the morphological, chemical, and electrical properties of the deposited CuZn thin films by utilizing a surface profiler, atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), UV photoelectron spectroscopy (UPS), and a 4-point probe. The thickness of the thin films was fixed at 200 ± 8 nm and the roughness of the thin films containing Cu was smaller than pure Zn thin films. XRD studies confirmed that the preferred phase changed, and this tendency is dependent on the ratio of Cu to Zn. AES spectra indicate that the obtained thin films consisted of Cu and Zn. The high resolution XPS spectra indicate that as the content of Cu increased, the intensities of Zn2+ decreased. The work function of CuZn thin films increased from 4.87 to 5.36 eV. The conductivity of CuZn alloy thin films was higher than pure metallic thin films.

Soft Magnetic Properties of High-Entropy Fe-Co-Ni-Cr-Al-Si Thin Films

Directory of Open Access Journals (Sweden)

Pei-Chung Lin

2016-08-01

Full Text Available Soft magnetic properties of Fe-Co-Ni-Al-Cr-Si thin films were studied. As-deposited Fe-Co-Ni-Al-Cr-Si nano-grained thin films showing no magnetic anisotropy were subjected to field-annealing at different temperatures to induce magnetic anisotropy. Optimized magnetic and electrical properties of Fe-Co-Ni-Al-Cr-Si films annealed at 200 °C are saturation magnetization 9.13 × 105 A/m, coercivity 79.6 A/m, out-of-plane uniaxial anisotropy field 1.59 × 103 A/m, and electrical resistivity 3.75 μΩ·m. Based on these excellent properties, we employed such films to fabricate magnetic thin film inductor. The performance of the high entropy alloy thin film inductors is superior to that of air core inductor.

Optics assembly for high power laser tools

Science.gov (United States)

Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

2016-06-07

There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

Powerful highly efficient KrF lamps excited by surface and barrier discharges

International Nuclear Information System (INIS)

Borisov, V M; Vodchits, V A; El'tsov, A V; Khristoforov, O B

1998-01-01

An investigation was made of the characteristics of KrF lamps with different types of excitation by surface and barrier discharges in which the dielectric material was sapphire. The conditions were determined for the attainment of an extremely high yield of the KrF* fluorescence with the internal efficiency η in ∼30 % and 22% for pulsed surface and barrier discharges, respectively. A homogeneous surface discharge was maintained without gas circulation when the pulse repetition rate was 5 x 10 4 Hz. Quasicontinuous excitation of a surface discharge at near-atmospheric pressure made it possible to reach a KrF* fluorescence power density of about 80 W cm -3 , which was close to the limit set by the kinetics of the gaseous medium. Under prolonged excitation conditions the intensity of the UV output radiation was limited by the permissible heating of the gas to a temperature above which the operating life of the gaseous mixture containing fluorine fell steeply. This was the reason for the advantage of surface over barrier discharges: the former were characterised by a high thermal conductivity of a thin (∼0.2 mm) plasma layer on the surface of the cooled dielectric, which made it possible to construct powerful highly efficient KrF and ArF lamps emitting UV radiation of up to 1 W cm -2 intensity. (laser system components)

HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

International Nuclear Information System (INIS)

2005-01-01

Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

Comparison of growth response to thinning in oak forests managed as coppice with standards and high forest

Science.gov (United States)

Gautam, S.; Hasenauer, H.; Pietsch, S. A.

2009-04-01

The BIOME-BGC model integrates the main physical, biological and physiological processes based on current understanding of ecophysiology to assess forest ecosystem dynamics. This study evaluates the application of the model to assess the thinning effects on coppiced oak forests in Austria. We analyze the growth response, i.e. growth efficiency (GE), nitrogen use efficiency (NUE), water use efficiency (WUE) and radiation use efficiency (RUE) of oak forests to thinning. The results of coppice with standards and high forests simulations are analysed for differences in simulated growth response after thinning. The forest field data of the year 2006 and the respective model runs are used to evaluate model application. Strong positive relationship (r2 = 0.90) with unbiased results and statistically insignificant differences between predicted and observed volume allows the use of the model as a diagnostic tool to assess management effects. Results indicate that the coppice with standards exhibits a significantly higher yield by 2.97% (i.e. 10 cubic meters per hectare in one rotation), a higher harvest (49.9%) but a lower growing stock (19.69%) than the high forests. The higher growing stock and the lower extraction in the high forests confirm that the high forest sequestrates significantly more carbon than the coppice with standards. Results show that thinning leads to an increase in the GE, the NUE and the WUE, and to a decrease in the RUE. Although the coppice with standards forest ecosystem exhibits higher values in all studied growth parameters, only the difference in the NUE was statistically significant. This verifies that the difference in the yield between the coppice with standards and the high forests is mainly governed by the NUE difference in stands after thinning. The coppice with standards system produces an equal amount of net primary production while consuming significantly less nitrogen (16%) compared to the high forest system. In the coppice with

Application of high power microwave vacuum electron devices

International Nuclear Information System (INIS)

Ding Yaogen; Liu Pukun; Zhang Zhaochuan; Wang Yong; Shen Bin

2011-01-01

High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

High Performance Infrared Plasmonic Metamaterial Absorbers and Their Applications to Thin-film Sensing

KAUST Repository

Yue, Weisheng

2016-04-07

Plasmonic metamaterial absorbers (PMAs) have attracted considerable attention for developing various sensing devices. In this work, we design, fabricate and characterize PMAs of different geometrical shapes operating in mid-infrared frequencies, and explore the applications of the PMAs as sensor for thin films. The PMAs, consisting of metal-insulator-metal stacks with patterned gold nanostructured surfaces (resonators), demonstrated high absorption efficiency (87 to 98 %) of electromagnetic waves in the infrared regime. The position and efficiency of resonance absorption are dependent on the shape of the resonators. Furthermore, the resonance wavelength of PMAs was sensitive to the thin film coated on the surface of the PMAs, which was tested using aluminum oxide (Al2O3) as the film. With increase of the Al2O3 thickness, the position of resonance absorption shifted to longer wavelengths. The dependence of the resonant wavelength on thin film thickness makes PMAs a suitable candidate as a sensor for thin films. Using this sensing strategy, PMAs have potential as a new method for thin film detection and in situ monitoring of surface reactions. © 2016 Springer Science+Business Media New York

High Performance Infrared Plasmonic Metamaterial Absorbers and Their Applications to Thin-film Sensing

KAUST Repository

Yue, Weisheng; Wang, Zhihong; Yang, Yang; Han, Jiaguang; Li, Jingqi; Guo, Zaibing; Tan, Hua; Zhang, Xixiang

2016-01-01

Plasmonic metamaterial absorbers (PMAs) have attracted considerable attention for developing various sensing devices. In this work, we design, fabricate and characterize PMAs of different geometrical shapes operating in mid-infrared frequencies, and explore the applications of the PMAs as sensor for thin films. The PMAs, consisting of metal-insulator-metal stacks with patterned gold nanostructured surfaces (resonators), demonstrated high absorption efficiency (87 to 98 %) of electromagnetic waves in the infrared regime. The position and efficiency of resonance absorption are dependent on the shape of the resonators. Furthermore, the resonance wavelength of PMAs was sensitive to the thin film coated on the surface of the PMAs, which was tested using aluminum oxide (Al2O3) as the film. With increase of the Al2O3 thickness, the position of resonance absorption shifted to longer wavelengths. The dependence of the resonant wavelength on thin film thickness makes PMAs a suitable candidate as a sensor for thin films. Using this sensing strategy, PMAs have potential as a new method for thin film detection and in situ monitoring of surface reactions. © 2016 Springer Science+Business Media New York

3D macroporous graphene frameworks for supercapacitors with high energy and power densities.

Science.gov (United States)

Choi, Bong Gill; Yang, Minho; Hong, Won Hi; Choi, Jang Wook; Huh, Yun Suk

2012-05-22

In order to develop energy storage devices with high power and energy densities, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate high-performance supercapacitors by building a three-dimensional (3D) macroporous structure that consists of chemically modified graphene (CMG). These 3D macroporous electrodes, namely, embossed-CMG (e-CMG) films, were fabricated by using polystyrene colloidal particles as a sacrificial template. Furthermore, for further capacitance boost, a thin layer of MnO(2) was additionally deposited onto e-CMG. The porous graphene structure with a large surface area facilitates fast ionic transport within the electrode while preserving decent electronic conductivity and thus endows MnO(2)/e-CMG composite electrodes with excellent electrochemical properties such as a specific capacitance of 389 F/g at 1 A/g and 97.7% capacitance retention upon a current increase to 35 A/g. Moreover, when the MnO(2)/e-CMG composite electrode was asymmetrically assembled with an e-CMG electrode, the assembled full cell shows remarkable cell performance: energy density of 44 Wh/kg, power density of 25 kW/kg, and excellent cycle life.

Structural and Optical Properties of Ultra-high Pure Hot Water Processed Ga2O3 Thin Film

Directory of Open Access Journals (Sweden)

Subramani SHANMUGAN

2016-05-01

Full Text Available Thin film based gas sensor is an advanced application of thin film especially Ga2O3 (GO thin film gas sensor is useful for high temperature gas sensor. The effect of moisture or environment on thin film properties has more influence on gas sensing properties. Radio Frequency sputtered Ga2O3 thin film was synthesized and processed in ultra-high pure hot water at 95 °C for different time durations. The structural properties were verified by the Xray Diffraction technique and the observed spectra revealed the formation of hydroxyl compound of Gallium (Gallium Oxide Dueterate – GOD on the surface of the thin film and evidenced for structural defects as an effect of moisture. Decreased crystallite size and increased dislocation density was showed the crystal defects of prepared film. From the Ultra Violet – Visible spectra, decreased optical transmittance was noticed for various processing time. The formation of needle like GOD was confirmed using Field Emission Secondary Electron Microscope (FESEM images.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7186

Improvement of transistor characteristics and stability for solution-processed ultra-thin high-valence niobium doped zinc-tin oxide thin film transistors

Energy Technology Data Exchange (ETDEWEB)

Jeng, Jiann-Shing, E-mail: jsjeng@mail.nutn.edu.tw

2016-08-15

Nb-doped Zinc tin oxide (NZTO) channel materials have been prepared by solution process in combination with the spin-coating method. All NZTO thin film transistors (TFTs) are n-type enhancement-mode devices, either without or with Nb additives. High-valence niobium ion (ionic charge = +5) has a larger ionic potential and similar ionic radius to Zn{sup 2+} and Sn{sup 4+} ions. As compared with the pure ZTO device, introducing Nb{sup 5+} ions into the ZTO channel layers can improve the electrical properties and bias stability of TFTs because of the reduction of the oxygen vacancies. This study discusses the connection among the material properties of the NZTO films and the electrical performance and bias stability of NZTO TFTs and how they are influenced by the Nb/(Nb + Sn) molar ratios of NZTO films. - Highlights: • Ultra-thin high-valence niobium doped zinc-tin oxide (NZTO) thin films are prepared using a solution process. • Nb dopants in ZTO films reduce the oxygen vacancy and subgap adsorption of the ZTO films. • The Nb-doping concentration of the NZTO channel layer has a strong influence on the TFT performance.

Micro-Raman spectroscopy studies of bulk and thin films of CuInTe2

International Nuclear Information System (INIS)

Ananthan, M R; Mohanty, Bhaskar Chandra; Kasiviswanathan, S

2009-01-01

Micro-Raman spectroscopy measurements were made on polycrystalline and amorphous thin films of CuInTe 2 as well as bulk polycrystalline CuInTe 2 . Various vibrational modes exhibited by the bulk and polycrystalline thin films were attributed to those expected for single crystal CuInTe 2 . Raman spectra of amorphous films presented a broad spectrum, decomposition of which revealed the presence of elemental tellurium on the film surface. Laser-induced changes on CuInTe 2 thin films were studied by acquiring spectra with higher laser beam power. Modes due to tellurium appeared when the spectra were acquired during laser–sample interaction, indicating tellurium segregation. The Raman spectra measured from polycrystalline films during high laser power irradiation did not show decrease in the intensity of the A 1 mode of CuInTe 2 in spite of loss of tellurium from the lattice. This has been interpreted as related to an increased contribution from the undistorted subsurface CuInTe 2 region at higher excitation power

Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

Directory of Open Access Journals (Sweden)

Jaekyun Kim

2015-10-01

Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

High-throughput characterization of film thickness in thin film materials libraries by digital holographic microscopy

International Nuclear Information System (INIS)

Lai Yiuwai; Hofmann, Martin R; Ludwig, Alfred; Krause, Michael; Savan, Alan; Thienhaus, Sigurd; Koukourakis, Nektarios

2011-01-01

A high-throughput characterization technique based on digital holography for mapping film thickness in thin-film materials libraries was developed. Digital holographic microscopy is used for fully automatic measurements of the thickness of patterned films with nanometer resolution. The method has several significant advantages over conventional stylus profilometry: it is contactless and fast, substrate bending is compensated, and the experimental setup is simple. Patterned films prepared by different combinatorial thin-film approaches were characterized to investigate and demonstrate this method. The results show that this technique is valuable for the quick, reliable and high-throughput determination of the film thickness distribution in combinatorial materials research. Importantly, it can also be applied to thin films that have been structured by shadow masking.

High-throughput characterization of film thickness in thin film materials libraries by digital holographic microscopy.

Science.gov (United States)

Lai, Yiu Wai; Krause, Michael; Savan, Alan; Thienhaus, Sigurd; Koukourakis, Nektarios; Hofmann, Martin R; Ludwig, Alfred

2011-10-01

A high-throughput characterization technique based on digital holography for mapping film thickness in thin-film materials libraries was developed. Digital holographic microscopy is used for fully automatic measurements of the thickness of patterned films with nanometer resolution. The method has several significant advantages over conventional stylus profilometry: it is contactless and fast, substrate bending is compensated, and the experimental setup is simple. Patterned films prepared by different combinatorial thin-film approaches were characterized to investigate and demonstrate this method. The results show that this technique is valuable for the quick, reliable and high-throughput determination of the film thickness distribution in combinatorial materials research. Importantly, it can also be applied to thin films that have been structured by shadow masking.

Applying RF Magnetron sputtering to prepare ZnO thin films and their characterization

International Nuclear Information System (INIS)

Saad, M.; Kassis, A.

2009-05-01

ZnO thin films were prepared using Rf magnetron sputtering under several preparation conditions (different values of deposition pressure, Rf power, substrate temperature). The optical properties of these films were investigated by measuring their transmission in the spectral range (300-1000 nm), and the electrical properties were investigated by measuring their electrical resistance. Results have been discussed in terms of the modified Thornton model for sputtered thin metal oxide films. Preparation conditions for depositing the highly resistive transparent i-ZnO buffer layer and the highly conducting transparent n-ZnO window layer for solar cells were proposed. (author)

High-conductance low-voltage organic thin film transistor with locally rearranged poly(3-hexylthiophene) domain by current annealing on plastic substrate

Science.gov (United States)

Pei, Zingway; Tsai, Hsing-Wang; Lai, Hsin-Cheng

2016-02-01

The organic material based thin film transistors (TFTs) are attractive for flexible optoelectronics applications due to the ability of lager area fabrication by solution and low temperature process on plastic substrate. Recently, the research of organic TFT focus on low operation voltage and high output current to achieve a low power organic logic circuit for optoelectronic device,such as e-paper or OLED displayer. To obtain low voltage and high output current, high gate capacitance and high channel mobility are key factors. The well-arranged polymer chain by a high temperature postannealing, leading enhancement conductivity of polymer film was a general method. However, the thermal annealing applying heat for all device on the substrate and may not applicable to plastic substrate. Therefore, in this work, the low operation voltage and high output current of polymer TFTs was demonstrated by locally electrical bias annealing. The poly(styrene-comethyl methacrylate) (PS-r-PMMA) with ultra-thin thickness is used as gate dielectric that the thickness is controlled by thermal treatment after spin coated on organic electrode. In electrical bias-annealing process, the PS-r- PMMA is acted a heating layer. After electrical bias-annealing, the polymer TFTs obtain high channel mobility at low voltage that lead high output current by a locally annealing of P3HT film. In the future, the locally electrical biasannealing method could be applied on plastic substrate for flexible optoelectronic application.

Low-field vortex dynamics in various high-Tc thin films

Indian Academy of Sciences (India)

Abstract. We present a novel ac susceptibility technique for the study of vortex creep in supercon- ducting thin films. With this technique we study the dynamics of dilute vortices in c-axis oriented. Y-123, Hg-1212, and Tl-1212 thin films, as well as a-axis oriented Hg-1212 thin films. Results on the Hg-1212 and Tl-1212 thin ...

14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

Science.gov (United States)

2010-01-01

... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When operating...

Ceramic-supported thin PVA pervaporation membranes combining high flux and high selectivity : contradicting the flux-selectivity paradigm

NARCIS (Netherlands)

Peters, T.A.; Poeth, C.H.S.; Benes, N.E.; Buijs, H.C.W.M.; Vercauteren, F.F.; Keurentjes, J.T.F.

2006-01-01

Thin, high-flux and highly selective cross-linked poly(vinyl)alcohol waterselective layers have been prepared on top of hollow fibre ceramic supports. The supports consist of an alpha-Al2O3 hollow fibre substrate and an intermediate gamma-Al2O3 layer, which provides a sufficiently smooth surface for

Highly spectrum-selective ultraviolet photodetector based on p-NiO/n-IGZO thin film heterojunction structure.

Science.gov (United States)

Li, H K; Chen, T P; Hu, S G; Li, X D; Liu, Y; Lee, P S; Wang, X P; Li, H Y; Lo, G Q

2015-10-19

Ultraviolet photodetector with p-n heterojunction is fabricated by magnetron sputtering deposition of n-type indium gallium zinc oxide (n-IGZO) and p-type nickel oxide (p-NiO) thin films on ITO glass. The performance of the photodetector is largely affected by the conductivity of the p-NiO thin film, which can be controlled by varying the oxygen partial pressure during the deposition of the p-NiO thin film. A highly spectrum-selective ultraviolet photodetector has been achieved with the p-NiO layer with a high conductivity. The results can be explained in terms of the "optically-filtering" function of the NiO layer.

High-frequency high-voltage high-power DC-to-DC converters

Science.gov (United States)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-09-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

Combinatorial thin film materials science: From alloy discovery and optimization to alloy design

Energy Technology Data Exchange (ETDEWEB)

Gebhardt, Thomas, E-mail: gebhardt@mch.rwth-aachen.de; Music, Denis; Takahashi, Tetsuya; Schneider, Jochen M.

2012-06-30

This paper provides an overview of modern alloy development, from discovery and optimization towards alloy design, based on combinatorial thin film materials science. The combinatorial approach, combining combinatorial materials synthesis of thin film composition-spreads with high-throughput property characterization has proven to be a powerful tool to delineate composition-structure-property relationships, and hence to efficiently identify composition windows with enhanced properties. Furthermore, and most importantly for alloy design, theoretical models and hypotheses can be critically appraised. Examples for alloy discovery, optimization, and alloy design of functional as well as structural materials are presented. Using Fe-Mn based alloys as an example, we show that the combination of modern electronic-structure calculations with the highly efficient combinatorial thin film composition-spread method constitutes an effective tool for knowledge-based alloy design.

Combinatorial thin film materials science: From alloy discovery and optimization to alloy design

International Nuclear Information System (INIS)

Gebhardt, Thomas; Music, Denis; Takahashi, Tetsuya; Schneider, Jochen M.

2012-01-01

This paper provides an overview of modern alloy development, from discovery and optimization towards alloy design, based on combinatorial thin film materials science. The combinatorial approach, combining combinatorial materials synthesis of thin film composition-spreads with high-throughput property characterization has proven to be a powerful tool to delineate composition–structure–property relationships, and hence to efficiently identify composition windows with enhanced properties. Furthermore, and most importantly for alloy design, theoretical models and hypotheses can be critically appraised. Examples for alloy discovery, optimization, and alloy design of functional as well as structural materials are presented. Using Fe-Mn based alloys as an example, we show that the combination of modern electronic-structure calculations with the highly efficient combinatorial thin film composition-spread method constitutes an effective tool for knowledge-based alloy design.

High-power, high-efficiency FELs

International Nuclear Information System (INIS)

Sessler, A.M.

1989-04-01

High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

Deposition of highly (111)-oriented PZT thin films by using metal organic chemical deposition

CERN Document Server

Bu, K H; Choi, D K; Seong, W K; Kim, J D

1999-01-01

Lead zirconate titanate (PZT) thin films have been grown on Pt/Ta/SiNx/Si substrates by using metal organic chemical vapor deposition with Pb(C sub 2 H sub 5) sub 4 , Zr(O-t-C sub 4 H sub 9) sub 4 , and Ti(O-i-C sub 3 H sub 7) sub 4 as source materials and O sub 2 as an oxidizing gas. The Zr fraction in the thin films was controlled by varying the flow rate of the Zr source material. The crystal structure and the electrical properties were investigated as functions of the composition. X-ray diffraction analysis showed that at a certain range of Zr fraction, highly (111)-oriented PZT thin films with no pyrochlore phases were deposited. On the other hand, at low Zr fractions, there were peaks from Pb-oxide phases. At high Zr fractions, peaks from pyrochlore phase were seen. The films also showed good electrical properties, such as a high dielectric constant of more than 1200 and a low coercive voltage of 1.35 V.

Thin film characterization by resonantly excited internal standing waves

Energy Technology Data Exchange (ETDEWEB)

Di Fonzio, S [SINCROTRONE TRIESTE, Trieste (Italy)

1996-09-01

This contribution describes how a standing wave excited in a thin film can be used for the characterization of the properties of the film. By means of grazing incidence X-ray reflectometry one can deduce the total film thickness. On the other hand in making use of a strong resonance effect in the electric field intensity distribution inside a thin film on a bulk substrate one can learn more about the internal structure of the film. The profile of the internal standing wave is proven by diffraction experiments. The most appropriate non-destructive technique for the subsequent thin film characterization is angularly dependent X-ray fluorescence analysis. The existence of the resonance makes it a powerful tool for the detection of impurities and of ultra-thin maker layers, for which the position can be determined with very high precision (about 1% of the total film thickness). This latter aspect will be discussed here on samples which had a thin Ti marker layer at different positions in a carbon film. Due to the resonance enhancement it was still possible to perform these experiments with a standard laboratory x-ray tube and with standard laboratory tool for marker or impurity detection in thin films.

Fabrication of thin TEM sample of ionic liquid for high-resolution ELNES measurements

Energy Technology Data Exchange (ETDEWEB)

Miyata, Tomohiro, E-mail: tomo-m@iis.u-tokyo.ac.jp; Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp

2017-07-15

Investigation of the local structure, ionic and molecular behavior, and chemical reactions at high spatial resolutions in liquids has become increasingly important. Improvements in these areas help to develop efficient batteries and improve organic syntheses. Transmission electron microscopy (TEM) and scanning-TEM (STEM) have excellent spatial resolution, and the electron energy-loss near edge structure (ELNES) measured by the accompanied electron energy-loss spectroscopy (EELS) is effective to analyze the liquid local structure owing to reflecting the electronic density of states. In this study, we fabricate a liquid-layer-only sample with thickness of single to tens nanometers using an ionic liquid. Because the liquid film has a thickness much less than the inelastic mean free path (IMFP) of the electron beam, the fine structure of the C-K edge electron energy loss near edge structure (ELNES) can be measured with sufficient resolution to allow meaningful analysis. The ELNES spectrum from the thin liquid film has been interpreted using first principles ELNES calculations. - Highlights: • A fabrication method of thin liquid film samples for STEM-EELS observations is proposed. • The thickness of the fabricated thin liquid film is about 10 nm. • An ELNES is measured from the thin liquid with a high energy resolution. • The peaks of the ELNES are interpreted using first principles calculations.

Using an ultra-thin non-doped orange emission layer to realize high efficiency white organic light-emitting diodes with low efficiency roll-off

Energy Technology Data Exchange (ETDEWEB)

Zhu, Liping; Chen, Jiangshan; Ma, Dongge, E-mail: mdg1014@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate University of the Chinese Academy of Sciences, Changchun 130022 (China); Zhao, Yongbiao [Luminous Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Zhang, Hongmei [Department of Materials Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China)

2014-06-28

By adopting an ultra-thin non-doped orange emission layer sandwiched between two blue emission layers, high efficiency white organic light-emitting diodes (WOLEDs) with reduced efficiency roll-off were fabricated. The optimized devices show a balanced white emission with Internationale de L'Eclairage of (0.41, 0.44) at the luminance of 1000 cd/m{sup 2}, and the maximum power efficiency, current efficiency (CE), and external quantum efficiency reach 63.2 lm/W, 59.3 cd/A, and 23.1%, which slightly shift to 53.4 lm/W, 57.1 cd/A, and 22.2% at 1000 cd/m{sup 2}, respectively, showing low efficiency roll-off. Detailed investigations on the recombination zone and the transient electroluminescence (EL) clearly reveal the EL processes of the ultra-thin non-doped orange emission layer in WOLEDs.

Water Vapour Propulsion Powered by a High-Power Laser-Diode

Science.gov (United States)

Minami, Y.; Uchida, S.

Most of the laser propulsion schemes now being proposed and developed assume neither power supplies nor on-board laser devices and therefore are bound to remote laser stations like a kite via a laser beam “string”. This is a fatal disadvantage for a space vehicle that flies freely though it is often said that no need of installing an energy source is an advantage of a laser propulsion scheme. The possibility of an independent laser propulsion space vehicle that carries a laser source and a power supply on board is discussed. This is mainly due to the latest development of high power laser diode (LD) technology. Both high specific impulse-low thrust mode and high thrust-low specific impulse mode can be selected by controlling the laser output by using vapour or water as a propellant. This mode change can be performed by switching between a high power continuous wave (cw), LD engine for high thrust with a low specific impulse mode and high power LD pumping Q-switched Nd:YAG laser engine for low thrust with the high specific impulse mode. This paper describes an Orbital Transfer Vehicle equipped with the above-mentioned laser engine system and fuel cell that flies to the Moon from a space platform or space hotel in Earth orbit, with cargo shipment from lunar orbit to the surface of the Moon, including the possibility of a sightseeing trip.

Thermoelectric effects of amorphous Ga-Sn-O thin film

Science.gov (United States)

Matsuda, Tokiyoshi; Uenuma, Mutsunori; Kimura, Mutsumi

2017-07-01

The thermoelectric effects of an amorphous Ga-Sn-O (a-GTO) thin film have been evaluated as a physical parameter of a novel oxide semiconductor. Currently, a-GTO thin films are greatly desired not only because they do not contain rare metals and are therefore free from problems on the exhaustion of resources and the increase in cost but also because their initial characteristics and performance stabilities are excellent when they are used in thin-film transistors. In this study, an a-GTO thin film was deposited on a quartz substrate by RF magnetron sputtering and postannealing was performed in air at 350 °C for 1 h using an annealing furnace. The Seebeck coefficient and electrical conductivity of the a-GTO thin film were -137 µV/K and 31.8 S/cm at room temperature, and -183 µV/K and 43.8 S/cm at 397 K, respectively, and as a result, the power factor was 1.47 µW/(cm·K2) at 397 K; these values were roughly as high as those of amorphous In-Ga-Zn-O (a-IGZO) thin films. Therefore, a-GTO thin films will be a candidate material for thermoelectric devices fabricated in a large area at a low cost by controlling the carrier mobility, carrier density, device structures, and so forth.

Treatment of thin stillage in a high-rate anaerobic fluidized bed bioreactor (AFBR).

Science.gov (United States)

Andalib, Mehran; Hafez, Hisham; Elbeshbishy, Elsayed; Nakhla, George; Zhu, Jesse

2012-10-01

The primary objective of this work was to investigate the treatability of thin stillage as a by-product of bioethanol production plants using an anaerobic fluidized bed bioreactor (AFBR) employing zeolite with average diameter of (d(m)) of 425-610 μm and specific surface area (SSA) of 26.5m(2)/g as the carrier media. Despite the very high strength of thin stillage with chemical oxygen demand of 130,000 mg TCOD/L and suspended solids of 47,000 mg TSS/L, the AFBR showed up to 88% TCOD and 78% TSS removal at very high organic and solids loading rates (OLR and SLR) of 29 kg COD/m(3)d and 10.5 kg TSS/m(3)d respectively and hydraulic retention time (HRT) of 3.5 days. Methane production rates of up to 160 L/d at the steady state equivalent to 40 L(CH4)/L(thin stillage)d and biogas production rate per reactor volume of 15.8L(gas)/L(reactor)d were achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

Substantial difference in target surface chemistry between reactive dc and high power impulse magnetron sputtering

Science.gov (United States)

Greczynski, G.; Mráz, S.; Schneider, J. M.; Hultman, L.

2018-02-01

The nitride layer formed in the target race track during the deposition of stoichiometric TiN thin films is a factor 2.5 thicker for high power impulse magnetron sputtering (HIPIMS), compared to conventional dc processing (DCMS). The phenomenon is explained using x-ray photoelectron spectroscopy analysis of the as-operated Ti target surface chemistry supported by sputter depth profiles, dynamic Monte Carlo simulations employing the TRIDYN code, and plasma chemical investigations by ion mass spectrometry. The target chemistry and the thickness of the nitride layer are found to be determined by the implantation of nitrogen ions, predominantly N+ and N2+ for HIPIMS and DCMS, respectively. Knowledge of this method-inherent difference enables robust processing of high quality functional coatings.

Influence of lattice distortion on phase transition properties of polycrystalline VO{sub 2} thin film

Energy Technology Data Exchange (ETDEWEB)

Lin, Tiegui [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Langping, E-mail: aplpwang@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Xiaofeng; Zhang, Yufen [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Yu, Yonghao, E-mail: yhyu@hit.edu.cn [Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, Harbin 150001 (China)

2016-08-30

Highlights: • Polycrystalline VO{sub 2} thin films were fabricated by high power impulse magnetron sputtering. • The reported lowest phase transition temperature for undoped polycrystalline VO{sub 2} thin film was reduced to 32 °C by this research. • XRD patterns at varied temperatures revealed that the main structual change was a gradual shift in interplanar spacing with temperature. - Abstract: In this work, high power impulse magnetron sputtering was used to control the lattice distortion in polycrystalline VO{sub 2} thin film. SEM images revealed that all the VO{sub 2} thin films had crystallite sizes of below 20 nm, and similar configurations. UV–vis-near IR transmittance spectra measured at different temperatures showed that most of the as-deposited films had a typical metal–insulator transition. Four-point probe resistivity results showed that the transition temperature of the films varied from 54.5 to 32 °C. The X-ray diffraction (XRD) patterns of the as-deposited films revealed that most were polycrystalline monoclinic VO{sub 2}. The XRD results also confirmed that the lattice distortions in the as-deposited films were different, and the transition temperature decreased with the difference between the interplanar spacing of the as-deposited thin film and standard rutile VO{sub 2}. Furthermore, a room temperature rutile VO{sub 2} thin film was successfully synthesized when this difference was small enough. Additionally, XRD patterns measured at varied temperatures revealed that the phase transition process of the polycrystalline VO{sub 2} thin film was a coordinative deformation between grains with different orientations. The main structural change during the phase transition was a gradual shift in interplanar spacing with temperature.

Perovskite oxynitride LaTiOxNy thin films: Dielectric characterization in low and high frequencies

International Nuclear Information System (INIS)

Lu, Y.; Ziani, A.; Le Paven-Thivet, C.; Benzerga, R.; Le Gendre, L.; Fasquelle, D.; Kassem, H.

2011-01-01

Lanthanum titanium oxynitride (LaTiO x N y ) thin films are studied with respect to their dielectric properties in low and high frequencies. Thin films are deposited by radio frequency magnetron sputtering on different substrates. Effects of nitrogen content and crystalline quality on dielectric properties are investigated. In low-frequency range, textured LaTiO x N y thin films deposited on conductive single crystal Nb–STO show a dielectric constant ε′ ≈ 140 with low losses tanδ = 0.012 at 100 kHz. For the LaTiO x N y polycrystalline films deposited on conductive silicon substrates with platinum (Pt/Ti/SiO 2 /Si), the tunability reached up to 57% for a weak electric field of 50 kV/cm. In high-frequency range, epitaxial LaTiO x N y films deposited on MgO substrate present a high dielectric constant with low losses (ε′ ≈ 170, tanδ = 0.011, 12 GHz).

High speed micromachining with high power UV laser

Science.gov (United States)

Patel, Rajesh S.; Bovatsek, James M.

2013-03-01

Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

Power affects performance when the pressure is on: evidence for low-power threat and high-power lift.

Science.gov (United States)

Kang, Sonia K; Galinsky, Adam D; Kray, Laura J; Shirako, Aiwa

2015-05-01

The current research examines how power affects performance in pressure-filled contexts. We present low-power-threat and high-power-lift effects, whereby performance in high-stakes situations suffers or is enhanced depending on one's power; that is, the power inherent to a situational role can produce effects similar to stereotype threat and lift. Three negotiations experiments demonstrate that role-based power affects outcomes but only when the negotiation is diagnostic of ability and, therefore, pressure-filled. We link these outcomes conceptually to threat and lift effects by showing that (a) role power affects performance more strongly when the negotiation is diagnostic of ability and (b) underperformance disappears when the low-power negotiator has an opportunity to self-affirm. These results suggest that stereotype threat and lift effects may represent a more general phenomenon: When the stakes are raised high, relative power can act as either a toxic brew (stereotype/low-power threat) or a beneficial elixir (stereotype/high-power lift) for performance. © 2015 by the Society for Personality and Social Psychology, Inc.

Solvent-induced crystallization for hybrid perovskite thin-film photodetector with high-performance and low working voltage

International Nuclear Information System (INIS)

Hu, Wei; Yang, Shuzhen; Fan, Peng; Pan, Anlian; Wu, Runsheng; Yang, Junliang

2017-01-01

Organometal trihalide perovskites have emerged as a class of solution-processed semiconductors exhibiting remarkable optoelectronic properties. Using a high-quality perovskite thin film prepared by solvent-induced crystallization method and adopting a novel device configuration based on photon recycling effect, a perovskite thin-film photodetector has been constructed with the highest external quantum efficiency of 4.1  ×  10 4 % and responsivity of 219 A W −1 at a low bias of 1 V so far. The device working mechanism was further disclosed based on energy band bending model. The high-performance and low working-voltage perovskite thin-film photodetector will find potential applications in photodetection and optoelectronic integrated circuits. (paper)

Reserve, thin form-factor, hypochlorite-based cells for powering portable systems: Manufacture (including MEMS processes), performance and characterization

Energy Technology Data Exchange (ETDEWEB)

Cardenas-Valencia, Andres M.; Langebrake, Larry [Center for Ocean Technology, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL (United States); Biver, Carl J. [Center for Ocean Technology, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL (United States); Department of Chemical Engineering, University of South Florida, 4202 E. Fowler Ave. Tampa, FL (United States)

2007-03-30

This work focuses on fabrication routes and performance evaluation of thin form-factors, reserve cells, as a powering alternative for expendable and/or remotely operated systems. The catalytic decomposition of sodium hypochlorite solutions is revisited herein with two cost-effective anodes: zinc and aluminum. Aluminum, even though the most expensive of the utilized anodes, constituted cells with double the energy content (up to 55 Wh kg{sup -1}) than those fabricated with zinc. Even though the hypochlorite concentration in the solution limits the cells' operational life, attractive performances (1.0 V with a current of 10 mA) for the manufactured cells are obtained. It is shown that micro fabrication processes, allowing for close electrodes interspacing, provided high faradic and columbic efficiencies of up to 70 and 100%, respectively. Obtained specific energies (50-120 Wh kg{sup -1}) are in the same order of magnitude than batteries currently used for powering deployable systems. Experimental results show that a simple model that linearly relates over potentials and the electrical load, adequately describe all the cell designs. A mathematical model based on a kinetic-mechanistic scheme that relates the current output as a function of time agrees fairly well with results obtained activating cells with various concentrations of NaOCl solutions. (author)

Advanced High Voltage Power Device Concepts

CERN Document Server

Baliga, B Jayant

2012-01-01

Advanced High Voltage Power Device Concepts describes devices utilized in power transmission and distribution equipment, and for very high power motor control in electric trains and steel-mills. Since these devices must be capable of supporting more than 5000-volts in the blocking mode, this books covers operation of devices rated at 5,000-V, 10,000-V and 20,000-V. Advanced concepts (the MCT, the BRT, and the EST) that enable MOS-gated control of power thyristor structures are described and analyzed in detail. In addition, detailed analyses of the silicon IGBT, as well as the silicon carbide MOSFET and IGBT, are provided for comparison purposes. Throughout the book, analytical models are generated to give a better understanding of the physics of operation for all the structures. This book provides readers with: The first comprehensive treatment of high voltage (over 5000-volts) power devices suitable for the power distribution, traction, and motor-control markets;  Analytical formulations for all the device ...

Preliminary experiments using light-initiated high explosive for driving thin flyer plates

International Nuclear Information System (INIS)

Benham, R.A.

1980-02-01

Light-initiated high explosive, silver acelytide - silver-nitrate (SASN), has been used to produce simulated x ray blow-off impulse loading on reentry vehicles to study the system structural response. SASN can be used to accelerate thin flyer plates to high terminal velocities which, in turn, can deliver a pressure pulse that can be tailored to the target material. This process is important for impulse tests where both structural and material response is desired. The theories used to calculate the dynamic state of the flyer plate prior to impact are summarized. Data from several experiments are presented which indicate that thin flyer plates can be properly accelerated and that there are predictive techniques available which are adequate to calculate the motion of the flyer plate. Recommendations are made for future study that must be undertaken to make the SASN flyer plate technique usable

High-power density miniscale power generation and energy harvesting systems

International Nuclear Information System (INIS)

Lyshevski, Sergey Edward

2011-01-01

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro (∼100 μW) to medium (∼100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems.

Dielectric relaxation of barium strontium titanate and application to thin films for DRAM capacitors

Science.gov (United States)

Baniecki, John David

This thesis examines the issues associated with incorporating the high dielectric constant material Barium Strontium Titanate (BSTO) in to the storage capacitor of a dynamic random access memory (DRAM). The research is focused on two areas: characterizing and understanding the factors that control charge retention in BSTO thin films and modifying the electrical properties using ion implantation. The dielectric relaxation of BSTO thin films deposited by metal-organic chemical vapor deposition (MOCVD) is investigated in the time and frequency domains. It is shown that the frequency dispersion of the complex capacitance of BSTO thin films can be understood in terms of a power-law frequency dependence from 1mHz to 20GHz. From the correspondence between the time and frequency domain measurements, it is concluded that the power-law relaxation currents extend back to the nano second regime of DRAM operation. The temperature, field, and annealing dependence of the dielectric relaxation currents are also investigated and mechanisms for the observed power law relaxation are explored. An equivalent circuit model of a high dielectric constant thin film capacitor is developed based on the electrical measurements and implemented in PSPICE. Excellent agreement is found between the experimental and simulated electrical characteristics showing the utility of the equivalent circuit model in simulating the electrical properties of high dielectric constant thin films. Using the equivalent circuit model, it is shown that the greatest charge loss due to dielectric relaxation occurs during the first read after a refresh time following a write to the opposite logic state for a capacitor that has been written to the same logic state for a long time (opposite state write charge loss). A theoretical closed form expression that is a function of three material parameters is developed which estimates the opposite state write charge loss due to dielectric relaxation. Using the closed form

Overview of the HiLASE project: high average power pulsed DPSSL systems for research and industry

Czech Academy of Sciences Publication Activity Database

Divoký, Martin; Smrž, Martin; Chyla, Michal; Sikocinski, Pawel; Severová, Patricie; Novák, Ondřej; Huynh, Jaroslav; Nagisetty, Siva S.; Miura, Taisuke; Pilař, Jan; Slezák, Jiří; Sawicka, Magdalena; Jambunathan, Venkatesan; Vanda, Jan; Endo, Akira; Lucianetti, Antonio; Rostohar, Danijela; Mason, P.D.; Phillips, P.J.; Ertel, K.; Banerjee, S.; Hernandez-Gomez, C.; Collier, J.L.; Mocek, Tomáš

2014-01-01

Roč. 2, SI (2014), s. 1-10 ISSN 2095-4719 R&D Projects: GA MŠk ED2.1.00/01.0027; GA MŠk EE2.3.20.0143; GA MŠk EE2.3.30.0057 Grant - others:HILASE(XE) CZ.1.05/2.1.00/01.0027; OP VK 6(XE) CZ.1.07/2.3.00/20.0143; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : DPSSL * Yb3C:YAG * thin-disk * multi-slab * pulsed high average power laser Subject RIV: BH - Optics, Masers, Lasers

Power MOSFET Linearizer of a High-Voltage Power Amplifier for High-Frequency Pulse-Echo Instrumentation.

Science.gov (United States)

Choi, Hojong; Woo, Park Chul; Yeom, Jung-Yeol; Yoon, Changhan

2017-04-04

A power MOSFET linearizer is proposed for a high-voltage power amplifier (HVPA) used in high-frequency pulse-echo instrumentation. The power MOSFET linearizer is composed of a DC bias-controlled series power MOSFET shunt with parallel inductors and capacitors. The proposed scheme is designed to improve the gain deviation characteristics of the HVPA at higher input powers. By controlling the MOSFET bias voltage in the linearizer, the gain reduction into the HVPA was compensated, thereby reducing the echo harmonic distortion components generated by the ultrasonic transducers. In order to verify the performance improvement of the HVPA implementing the power MOSFET linearizer, we measured and found that the gain deviation of the power MOSFET linearizer integrated with HVPA under 10 V DC bias voltage was reduced (-1.8 and -0.96 dB, respectively) compared to that of the HVPA without the power MOSFET linearizer (-2.95 and -3.0 dB, respectively) when 70 and 80 MHz, three-cycle, and 26 dB m input pulse waveforms are applied, respectively. The input 1-dB compression point (an index of linearity) of the HVPA with power MOSFET linearizer (24.17 and 26.19 dB m at 70 and 80 MHz, respectively) at 10 V DC bias voltage was increased compared to that of HVPA without the power MOSFET linearizer (22.03 and 22.13 dB m at 70 and 80 MHz, respectively). To further verify the reduction of the echo harmonic distortion components generated by the ultrasonic transducers, the pulse-echo responses in the pulse-echo instrumentation were compared when using HVPA with and without the power MOSFET linearizer. When three-cycle 26 dB m input power was applied, the second, third, fourth, and fifth harmonic distortion components of a 75 MHz transducer driven by the HVPA with power MOSFET linearizer (-48.34, -44.21, -48.34, and -46.56 dB, respectively) were lower than that of the HVPA without the power MOSFET linearizer (-45.61, -41.57, -45.01, and -45.51 dB, respectively). When five-cycle 20 dB m input

Thermal properties and stabilities of polymer thin films

International Nuclear Information System (INIS)

Kanaya, Toshiji; Kawashima, Kazuko; Inoue, Rintaro; Miyazaki, Tsukasa

2009-01-01

Recent extensive studies have revealed that polymer thin films showed very interesting but unusual thermal properties and stabilities. In the article we show that X-ray reflectivity and neutron reflectivity are very powerful tools to study the anomalous properties of polymer thin films. (author)

High impact data visualization with Power View, Power Map, and Power BI

CERN Document Server

Aspin, Adam

2014-01-01

High Impact Data Visualization with Power View, Power Map, and Power BI helps you take business intelligence delivery to a new level that is interactive, engaging, even fun, all while driving commercial success through sound decision-making. Learn to harness the power of Microsoft's flagship, self-service business intelligence suite to deliver compelling and interactive insight with remarkable ease. Learn the essential techniques needed to enhance the look and feel of reports and dashboards so that you can seize your audience's attention and provide them with clear and accurate information. Al

Highly polarized single-c-domain single-crystal Pb(Mn,Nb)O(3)-PZT thin films.

Science.gov (United States)

Wasa, Kiyotaka; Adachi, Hideaki; Nishida, Ken; Yamamoto, Takashi; Matsushima, Tomoaki; Kanno, Isaku; Kotera, Hidetoshi

2012-01-01

In-plane unstrained single-c-domain/single-crystal thin films of PZT-based ternary ferroelectric perovskite, ξPb(Mn,Nb)O3-(1 - ξ)PZT, were grown on SrRuO(3)/Pt/MgO substrates using magnetron sputtering followed by quenching. The sputtered unstrained thin films exhibit unique ferroelectric properties: high coercive field, Ec > 180 kV/cm, large remanent polarization, P(r) = 100 μC/cm(2), small relative dielectric constants, ε* = 100 to 150, high Curie temperature, Tc = ~600 °C, and bulk-like large transverse piezoelectric constants, e31,f = -12.0 C/m(2) for PZT(48/52) at ξ = 0.06. The unstrained thin films are an ideal structure to extract the bulk ferroelectric properties. Their micro-structures and ferroelectric properties are discussed in relation to the potential applications for piezoelectric MEMS. © 2012 IEEE

Porous CrN thin films by selectively etching CrCuN for symmetric supercapacitors

KAUST Repository

Wei, Binbin

2018-03-18

Transition metal nitrides are regarded as a new class of excellent electrode materials for high-performance supercapacitors due to their superior chemical stability and excellent electrical conductivity. We synthesize successfully the porous CrN thin films for binder-free supercapacitor electrodes by reactive magnetron co-sputtering and selective chemical etching. The porous CrN thin film electrodes exhibit high-capacitance performance (31.3 mF cm−2 at 1.0 mA cm−2) and reasonable cycling stability (94% retention after 20000 cycles). Moreover, the specific capacitance is more than two-fold higher than that of the CrN thin film electrodes in previous work. In addition, a symmetric supercapacitor device with a maximum energy density of 14.4 mWh cm−3 and a maximum power density of 6.6 W cm−3 is achieved. These findings demonstrate that the porous CrN thin films will have potential applications in supercapacitors.

Porous CrN thin films by selectively etching CrCuN for symmetric supercapacitors

Science.gov (United States)

Wei, Binbin; Mei, Gui; Liang, Hanfeng; Qi, Zhengbing; Zhang, Dongfang; Shen, Hao; Wang, Zhoucheng

2018-05-01

Transition metal nitrides are regarded as a new class of excellent electrode materials for high-performance supercapacitors due to their superior chemical stability and excellent electrical conductivity. We synthesize successfully the porous CrN thin films for binder-free supercapacitor electrodes by reactive magnetron co-sputtering and selective chemical etching. The porous CrN thin film electrodes exhibit high-capacitance performance (31.3 mF cm-2 at 1.0 mA cm-2) and reasonable cycling stability (94% retention after 20000 cycles). Moreover, the specific capacitance is more than two-fold higher than that of the CrN thin film electrodes in previous work. In addition, a symmetric supercapacitor device with a maximum energy density of 14.4 mWh cm-3 and a maximum power density of 6.6 W cm-3 is achieved. These findings demonstrate that the porous CrN thin films will have potential applications in supercapacitors.

Eighth CW and High Average Power RF Workshop

CERN Document Server

2014-01-01

We are pleased to announce the next Continuous Wave and High Average RF Power Workshop, CWRF2014, to take place at Hotel NH Trieste, Trieste, Italy from 13 to 16 May, 2014. This is the eighth in the CWRF workshop series and will be hosted by Elettra - Sincrotrone Trieste S.C.p.A. (www.elettra.eu). CWRF2014 will provide an opportunity for designers and users of CW and high average power RF systems to meet and interact in a convivial environment to share experiences and ideas on applications which utilize high-power klystrons, gridded tubes, combined solid-state architectures, high-voltage power supplies, high-voltage modulators, high-power combiners, circulators, cavities, power couplers and tuners. New ideas for high-power RF system upgrades and novel ways of RF power generation and distribution will also be discussed. CWRF2014 sessions will start on Tuesday morning and will conclude on Friday lunchtime. A visit to Elettra and FERMI will be organized during the workshop. ORGANIZING COMMITTEE (OC): Al...

Ultra-high current density thin-film Si diode

Science.gov (United States)

Wang, Qi [Littleton, CO

2008-04-22

A combination of a thin-film .mu.c-Si and a-Si:H containing diode structure characterized by an ultra-high current density that exceeds 1000 A/cm.sup.2, comprising: a substrate; a bottom metal layer disposed on the substrate; an n-layer of .mu.c-Si deposited the bottom metal layer; an i-layer of .mu.c-Si deposited on the n-layer; a buffer layer of a-Si:H deposited on the i-layer, a p-layer of .mu.c-Si deposited on the buffer layer; and a top metal layer deposited on the p-layer.

PEALD grown high-k ZrO{sub 2} thin films on SiC group IV compound semiconductor

Energy Technology Data Exchange (ETDEWEB)

Khairnar, A. G., E-mail: agkhairnar@gmail.com; Patil, V. S.; Agrawal, K. S.; Salunke, R. S.; Mahajan, A. M., E-mail: ammahajan@nmu.ac.in [North Maharashtra University, Department of Electronics, School of Physical Sciences (India)

2017-01-15

The study of ZrO{sub 2} thin films on SiC group IV compound semiconductor has been studied as a high mobility substrates. The ZrO{sub 2} thin films were deposited using the Plasma Enhanced Atomic Layer Deposition System. The thickness of the thin films were measured using ellipsometer and found to be 5.47 nm. The deposited ZrO{sub 2} thin films were post deposition annealed in rapid thermal annealing chamber at temperature of 400°Ð¡. The atomic force microscopy and X-гау photoelectron spectroscopy has been carried out to study the surface topography, roughness and chemical composition of thin film, respectively.

Platinum containing amorphous hydrogenated carbon (a-C:H/Pt) thin films as selective solar absorbers

International Nuclear Information System (INIS)

Lan, Yung-Hsiang; Brahma, Sanjaya; Tzeng, Y.H.; Ting, Jyh-Ming

2014-01-01

We have investigated a double-cermet structured thin film in which an a-C:H thin film was used as an anti-reflective (AR) layer and two platinum-containing amorphous hydrogenated carbon (a-C:H/Pt) thin films were used as the double cermet layers. A reactive co-sputter deposition method was used to prepare both the anti-reflective and cermet layers. Effects of the target power and heat treatment were studied. The obtained films were characterized using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy. The optical absorptance and emittance of the as deposited and annealed films were determined using UV–vis-NIR spectroscopy. We show that the optical absorptance of the resulting double-cermet structured thin film is as high as 96% and remains to be 91% after heat treatment at 400 °C, indicating the thermal stability of the film

Metallic substrate materials for thin film oxygen transport membranes for application in a fossil power plant

Energy Technology Data Exchange (ETDEWEB)

Xing, Y.; Baumann, S.; Sebold, D.; Meulenberg, W.A.; Stoever, D. [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF) - IEF-1 Materials Synthesis and Processing

2010-07-01

La{sub 0.58}Sr{sub 0.4}CO{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF58428) and Ba{sub 0.5}Sr{sub 0.5}CO{sub 0.8}Fe{sub 3-{delta}} (BSCF5582) exhibit high oxygen permeability due to their high ionic and electronic conductivity. For this reason they are under discussion for application in oxygen transport membranes (OTMs) in zero-emission power plants using oxyfuel technology. A thin film membrane which can increase the oxygen flux is beneficial and a structural substrate is required. Two types of Ni-base alloys were studied as substrate material candidates with a number of advantages, such as high strength, high temperature stability, easy joining and similar thermal expansion coefficient to the selected perovskite materials. Chemical compositions and thermal expansion coefficients of Ni-base alloys were measured in this study. LSCF58428 and BSCF5582 layers were screen printed on Ni-based alloys and co-fired at high temperature in air. The microstructure and element analysis of samples were characterized by scanning electron microscopy (SEM and EDX). A Ni-base alloy, MCrAlY, with a high Al content was the most suitable substrate material, and showed better chemical compatibility with perovskite materials at high temperature than Hastelloy X, which is a chromia-forming Ni-base alloy. A reaction occurred between Sr in the perovskite and the alumina surface layers on MCr-AlY. However, the reaction zone did not increase in thickness during medium-term annealing at 800 C in air. Hence, it is expected that this reaction will not prevent the application of MCr-AlY as a substrate material. (orig.)

Lightweight Solar Power for Small Satellites

Science.gov (United States)

Nabors, Sammy A.

2015-01-01

The innovation targets small satellites or CubeSats for which conventional deployable arrays are not feasible due to their size, weight and complexity. This novel solar cell array includes a thin and flexible photovoltaic cell applied to an inflatable structure to create a high surface area array for collecting solar energy in a lightweight, simple and deployable structure. The inflatable array, with its high functional surface area, eliminates the need and the mechanisms required to point the system toward the sun. The power density achievable in these small arrays is similar to that of conventional high-power deployable/pointable arrays used on large satellites or space vehicles. Although inflatable solar arrays have been previously considered by others, the arrays involved the use of traditional rigid solar cells. Researchers are currently working with thin film photovoltaics from various suppliers so that the NASA innovation is not limited to any particular solar cell technology. NASA has built prototypes and tested functionality before and after inflation. As shown in the current-voltage currents below, deployment does not damage the cell performance.

Polymerization of polyethers initiated by irradiation with high power pulsed electron beams

International Nuclear Information System (INIS)

Gerber, V.D.; Tolkachev, V.S.; Chmukh, V.N.

1982-01-01

Air oxygen effect on thin-layer polymerization of polyethers, initiated by irradiation with powerful pulse electron beams is studied using the method of IR-spectrophotometry. The analysis of experimental data has shown that in polyether surface layer polymerization is suppressed by oxygen, concentration of which in the layer remains stable at the expense of diffusion from air during two consequent irradiation pulses

Seebeck effect of some thin film carbides

International Nuclear Information System (INIS)

Beensh-Marchwicka, G.; Prociow, E.

2002-01-01

Several materials have been investigated for high-temperature thin film thermocouple applications. These include silicon carbide with boron (Si-C-B), ternary composition based on Si-C-Mn, fourfold composition based on Si-C-Zr-B and tantalum carbide (TaC). All materials were deposited on quartz or glass substrates using the pulse sputter deposition technique. Electrical conduction and thermoelectric power were measured for various compositions at 300-550 K. It has been found, that the efficiency of thermoelectric power of films containing Si-C base composition was varied from 0.0015-0.034 μW/cmK 2 . However for TaC the value about 0.093 μW/cmK 2 was obtained. (author)

Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

Science.gov (United States)

Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

2018-02-01

Broad area lasers that are tailored to be most efficient at the highest achievable optical output power are sought by industry to decrease operation costs and improve system performance. Devices using Extreme-Double-ASymmetric (EDAS) epitaxial designs are promising candidates for improved efficiency at high optical output powers due to low series resistance, low optical loss and low carrier leakage. However, EDAS designs leverage ultra-thin p-side waveguides, meaning that the optical mode is shifted into the n-side waveguide, resulting in a low optical confinement in the active region, low gain and hence high threshold current, limiting peak performance. We introduce here explicit design considerations that enable EDAS-based devices to be developed with increased optical confinement in the active layer without changing the p-side layer thicknesses. Specifically, this is realized by introducing a third asymmetric component in the vicinity of the quantum well. We call this approach Extreme-Triple-ASymmetric (ETAS) design. A series of ETAS-based vertical designs were fabricated into broad area lasers that deliver up to 63% power conversion efficiency at 14 W CW optical output power from a 100 μm stripe laser, which corresponds to the operation point of a kW optical output power in a laser bar. The design process, the impact of structural changes on power saturation mechanisms and finally devices with improved performance will be presented.

Series-Tuned High Efficiency RF-Power Amplifiers

DEFF Research Database (Denmark)

Vidkjær, Jens

2008-01-01

An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

Hydrothermally formed three-dimensional nanoporous Ni(OH)2 thin-film supercapacitors.

Science.gov (United States)

Yang, Yang; Li, Lei; Ruan, Gedeng; Fei, Huilong; Xiang, Changsheng; Fan, Xiujun; Tour, James M

2014-09-23

A three-dimensional nanoporous Ni(OH)2 thin-film was hydrothermally converted from an anodically formed porous layer of nickel fluoride/oxide. The nanoporous Ni(OH)2 thin-films can be used as additive-free electrodes for energy storage. The nanoporous layer delivers a high capacitance of 1765 F g(-1) under three electrode testing. After assembly with porous activated carbon in asymmetric supercapacitor configurations, the devices deliver superior supercapacitive performances with capacitance of 192 F g(-1), energy density of 68 Wh kg(-1), and power density of 44 kW kg(-1). The wide working potential window (up to 1.6 V in 6 M aq KOH) and stable cyclability (∼90% capacitance retention over 10,000 cycles) make the thin-film ideal for practical supercapacitor devices.

High-power density miniscale power generation and energy harvesting systems

Energy Technology Data Exchange (ETDEWEB)

Lyshevski, Sergey Edward [Department of Electrical and Microelectronics Engineering, Rochester Institute of Technology, Rochester, NY 14623-5603 (United States)

2011-01-15

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro ({proportional_to}100 {mu}W) to medium ({proportional_to}100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems. (author)

Low-temperature liquid phase epitaxy of rare-earth-ion doped KY(WO4)2 thin layers

NARCIS (Netherlands)

Romanyuk, Y.E.; Utke, I.; Ehrentraut, D.; Pollnau, Markus; Garcia-Revilla, S.; Valiente, R.; Kuleshov, N.V.

2004-01-01

Rare-earth-ion doped KY(WO4)2 (hereafter KYW) is a promising material for novel solid-state lasers. Low laser threshold, high efficiency, high output powers, and third-order nonlinear effects have stimulated research towards miniaturized thin-film waveguide lasers and amplifiers for future photonic

Scaling invariance of spherical projectile fragmentation upon high-velocity impact on a thin continuous shield

Energy Technology Data Exchange (ETDEWEB)

Myagkov, N. N., E-mail: nn-myagkov@mail.ru [Russian Academy of Sciences, Institute of Applied Mechanics (Russian Federation)

2017-01-15

The problem of aluminum projectile fragmentation upon high-velocity impact on a thin aluminum shield is considered. A distinctive feature of this description is that the fragmentation has been numerically simulated using the complete system of equations of deformed solid mechanics by a method of smoothed particle hydrodynamics in three-dimensional setting. The transition from damage to fragmentation is analyzed and scaling relations are derived in terms of the impact velocity (V), ratio of shield thickness to projectile diameter (h/D), and ultimate strength (σ{sub p}) in the criterion of projectile and shield fracture. Analysis shows that the critical impact velocity V{sub c} (separating the damage and fragmentation regions) is a power function of σ{sub p} and h/D. In the supercritical region (V > V{sub c}), the weight-average fragment mass asymptotically tends to a power function of the impact velocity with exponent independent of h/D and σ{sub p}. Mean cumulative fragment mass distributions at the critical point are scale-invariant with respect to parameters h/D and σ{sub p}. Average masses of the largest fragments are also scale-invariant at V > V{sub c}, but only with respect to variable parameter σ{sub p}.

high power facto high power factor high power factor hybrid rectifier

African Journals Online (AJOL)

eobe

increase in the number of electrical loads that some kind of ... components in the AC power system. Thus, suppl ... al output power; assuring reliability in ... distribution systems. This can be ...... Thesis- Califonia Institute of Technology, Capitulo.

Area and energy efficient high-performance ZnO wavy channel thin-film transistor

KAUST Repository

Hanna, Amir

2014-09-01

Increased output current while maintaining low power consumption in thin-film transistors (TFTs) is essential for future generation large-area high-resolution displays. Here, we show wavy channel (WC) architecture in TFT that allows the expansion of the transistor width in the direction perpendicular to the substrate through integrating continuous fin features on the underlying substrate. This architecture enables expanding the TFT width without consuming any additional chip area, thus enabling increased performance while maintaining the real estate integrity. The experimental WCTFTs show a linear increase in output current as a function of number of fins per device resulting in (3.5×) increase in output current when compared with planar counterparts that consume the same chip area. The new architecture also allows tuning the threshold voltage as a function of the number of fin features included in the device, as threshold voltage linearly decreased from 6.8 V for planar device to 2.6 V for WC devices with 32 fins. This makes the new architecture more power efficient as lower operation voltages could be used for WC devices compared with planar counterparts. It was also found that field effect mobility linearly increases with the number of fins included in the device, showing almost \\\\(1.8×) enhancements in the field effect mobility than that of the planar counterparts. This can be attributed to higher electric field in the channel due to the fin architecture and threshold voltage shift. © 2014 IEEE.

Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

Science.gov (United States)

Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

2007-03-10

To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

High performance sandwich structured Si thin film anodes with LiPON coating

Science.gov (United States)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-04-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Electronic DC transformer with high power density

NARCIS (Netherlands)

Pavlovský, M.

2006-01-01

This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

Sexual aggression when power is new: Effects of acute high power on chronically low-power individuals.

Science.gov (United States)

Williams, Melissa J; Gruenfeld, Deborah H; Guillory, Lucia E

2017-02-01

Previous theorists have characterized sexually aggressive behavior as an expression of power, yet evidence that power causes sexual aggression is mixed. We hypothesize that power can indeed create opportunities for sexual aggression-but that it is those who chronically experience low power who will choose to exploit such opportunities. Here, low-power men placed in a high-power role showed the most hostility in response to a denied opportunity with an attractive woman (Studies 1 and 2). Chronically low-power men and women given acute power were the most likely to say they would inappropriately pursue an unrequited workplace attraction (Studies 3 and 4). Finally, having power over an attractive woman increased harassment behavior among men with chronic low, but not high, power (Study 5). People who see themselves as chronically denied power appear to have a stronger desire to feel powerful and are more likely to use sexual aggression toward that end. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

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.

Choroidal thinning in high myopia measured by optical coherence tomography

Directory of Open Access Journals (Sweden)

Ikuno Y

2013-05-01

Full Text Available Yasushi Ikuno, Satoko Fujimoto, Yukari Jo, Tomoko Asai, Kohji NishidaDepartment of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, JapanPurpose: To investigate the rate of choroidal thinning in highly myopic eyes.Patients and methods: A retrospective observational study of 37 eyes of 26 subjects (nine males and 17 females, mean age 39.6 ± 7.7 years with high myopia but no pathologies who had undergone spectral domain optical coherence tomography and repeated the test 1 year later (1 ± 0.25 year at Osaka University Hospital, Osaka, Japan. Patients older than 50 years with visual acuity worse than 20/40 or with whitish chorioretinal atrophy involving the macula were excluded. Two masked raters measured the choroidal thicknesses (CTs at the foveda, 3 mm superiorly, inferiorly, temporally, and nasally on the images and averaged the values. The second examination was about 365 days after the baseline examination. The CT reduction per year (CTRPY was defined as (CT 1 year after - baseline CT/days between the two examinations × 365. The retinal thicknesses were also investigated.Results: The CTRPY at the fovea was −1.0 ± 22.0 µm (range –50.2 to 98.5 at the fovea, –6.5 ± 24.3 µm (range −65.8 to 90.2 temporally, –0.5 ± 22.3 µm (range –27.1 to 82.5 nasally, –9.7 ± 21.7 µm (range –40.1 to 60.1 superiorly, and –1.4 ± 25.5 µm (range –85.6 to 75.2 inferiorly. There were no significant differences in the CTRPY at each location (P = 0.34. The CT decreased significantly (P < 0.05 only superiorly. The superior CTRPY was negatively correlated with the axial length (P < 0.05. The retinal thickness at the fovea did not change. Stepwise analysis for CTRPY selected axial length (P = 0.04, R2 = 0.13 and age (P = 0.08, R2 = 0.21 as relevant factors.Conclusions: The highly myopic choroid might gradually thin and be affected by many factors. Location and axial length are key factors to regulate the rate of choroidal

Switching transients in high-frequency high-power converters using power MOSFET's

Science.gov (United States)

Sloane, T. H.; Owen, H. A., Jr.; Wilson, T. G.

1979-01-01

The use of MOSFETs in a high-frequency high-power dc-to-dc converter is investigated. Consideration is given to the phenomena associated with the paralleling of MOSFETs and to the effect of stray circuit inductances on the converter circuit performance. Analytical relationships between various time constants during the turning-on and turning-off intervals are derived which provide estimates of plateau and peak levels during these intervals.

Optimized grid design for thin film solar panels

NARCIS (Netherlands)

Deelen, J. van; Klerk, L.; Barink, M.

2014-01-01

There is a gap in efficiency between record thin film cells and mass produced thin film solar panels. In this paper we quantify the effect of monolithic integration on power output for various configurations by modeling and present metallization as a way to improve efficiency of solar panels. Grid

High Power Electron Accelerator Prototype

CERN Document Server

Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

2005-01-01

In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

PowerShades II. Optimisation and validation of highly transparent photovoltaic. Final report

Energy Technology Data Exchange (ETDEWEB)

2010-07-15

The objective of the project is continued development and validation of a novel Danish photovoltaic product with the work title ''PowerShade''. The PowerShade insulating glazing unit (IGU) is a combination of a strong solar shading device and a power producing photovoltaic coating. The core technology in the PowerShade IGU is a thin film silicon photovoltaic generator applied to a micro structured substrate. The geometry of the substrate provides the unique combination of properties that characterizes the PowerShade module - strong progressive shading, high transparency, and higher electrical output than other semitransparent photovoltaic products with similar transparencies. The project activities fall in two categories, namely development of the processing/product and validation of the product properties. The development part of the project is focussed on increasing the efficiency of the photovoltaic generator by changing from a single-stack type cell to a tandem-stack type cell. The inclusion of PowerShade cells in insulating glazing (IG) units is also addressed in this project. The validation part of the project aims at validation of stability, thermal and optical properties as well as validation of the electrical yield of the product. The validation of thermal and optical properties has been done using full size modules installed in a test facility built during the 2006-08 ''PowerShades'' project. The achieved results will be vital in the coming realisation of a commercial product. Initial processing steps have been automated, and more efficient tandem-type solar cells have been developed. A damp heat test of an IGU has been carried out without any degradation of the solar cell. The PowerShade module assembly concept has been further developed and discussed with different automation equipment vendors and a pick-and-place tool developed. PowerShade's influence on the indoor climate has been modelled and verified by

Layered Cu-based electrode for high-dielectric constant oxide thin film-based devices

International Nuclear Information System (INIS)

Fan, W.; Saha, S.; Carlisle, J.A.; Auciello, O.; Chang, R.P.H.; Ramesh, R.

2003-01-01

Ti-Al/Cu/Ta multilayered electrodes were fabricated on SiO 2 /Si substrates by ion beam sputtering deposition, to overcome the problems of Cu diffusion and oxidation encountered during the high dielectric constant (κ) materials integration. The Cu and Ta layers remained intact through the annealing in oxygen environment up to 600 deg. C. The thin oxide layer, formed on the Ti-Al surface, effectively prevented the oxygen penetration toward underneath layers. Complex oxide (Ba x Sr 1-x )TiO 3 (BST) thin films were grown on the layered Ti-Al/Cu/Ta electrodes using rf magnetron sputtering. The deposited BST films exhibited relatively high permittivity (150), low dielectric loss (0.007) at zero bias, and low leakage current -8 A/cm 2 at 100 kV/cm

Resonant High Power Combiners

CERN Document Server

Langlois, Michel; Peillex-Delphe, Guy

2005-01-01

Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

High Average Power, High Energy Short Pulse Fiber Laser System

Energy Technology Data Exchange (ETDEWEB)

Messerly, M J

2007-11-13

Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

Power Constrained High-Level Synthesis of Battery Powered Digital Systems

DEFF Research Database (Denmark)

Nielsen, Sune Fallgaard; Madsen, Jan

2003-01-01

We present a high-level synthesis algorithm solving the combined scheduling, allocation and binding problem minimizing area under both latency and maximum power per clock-cycle constraints. Our approach eliminates the large power spikes, resulting in an increased battery lifetime, a property...... of utmost importance for battery powered embedded systems. Our approach extends the partial-clique partitioning algorithm by introducing power awareness through a heuristic algorithm which bounds the design space to those of power feasible schedules. We have applied our algorithm on a set of dataflow graphs...

Low temperature ITO thin film deposition on PES substrate using pulse magnetron sputtering

International Nuclear Information System (INIS)

Lin, Y.C.; Li, J.Y.; Yen, W.T.

2008-01-01

Experiments were conducted using pulse magnetron sputtering (PMS) to deposit transparent conducting indium tin oxide (ITO) thin film onto flexible polyethersulfone (PES) plastic substrates. The thin film microstructure, optoelectronic and residual stress were analyzed using the modulating PMS power, work pressure, pulse frequency, duty cycle and cycle time process parameters. The residual stress of the thin film was determined by scanning electron microscopy (SEM) combined with the Sony equation. The experimental results show that PMS has a lower process temperature, higher deposition rate and lower resistivity compared with the radio frequency process at the same output power. The duty cycle increase produces the optimum optoelectronic characteristics. When the pressure, power, duty cycle and sputter time are increased, the thin film stress will also increase, causing flexural distortion in the PES plastic substrate. When the deposition thickness reaches 1.5 μm, ITO thin film will appear with a distinct split. Under 5 mtorr work pressure, 60 W power, 33 μs duty time and 2 μs pulse reverse time at duty cycle 95%, thin film with an optimized electrical 3.0 x 10 -4 Ω-cm, RMS surface roughness of 0.85 nm and visible region optical transmittance will be achieved with acquisition of over 85%

Wafer-scale growth of highly textured piezoelectric thin films by pulsed laser deposition for micro-scale sensors and actuators

Science.gov (United States)

Nguyen, M. D.; Tiggelaar, R.; Aukes, T.; Rijnders, G.; Roelof, G.

2017-11-01

Piezoelectric lead-zirconate-titanate (PZT) thin films were deposited on 4-inch (111)Pt/Ti/SiO2/Si(001) wafers using large-area pulsed laser deposition (PLD). This study was focused on the homogeneity in film thickness, microstructure, ferroelectric and piezoelectric properties of PZT thin films. The results indicated that the highly textured (001)-oriented PZT thin films with wafer-scale thickness homogeneity (990 nm ± 0.8%) were obtained. The films were fabricated into piezoelectric cantilevers through a MEMS microfabrication process. The measured longitudinal piezoelectric coefficient (d 33f = 210 pm/V ± 1.6%) and piezoelectric transverse coefficient (e 31f = -18.8 C/m2 ± 2.8%) were high and homogeneity across wafers. The high piezoelectric properties on Si wafers will extend industrial application of PZT thin films and further development of piezoMEMS.

High stability, high current DC-power supplies

International Nuclear Information System (INIS)

Hosono, K.; Hatanaka, K.; Itahashi, T.

1995-01-01

Improvements of the power supplies and the control system of the AVF cyclotron which is used as an injector to the ring cyclotron and of the transport system to the ring cyclotron were done in order to get more high quality and more stable beam. The power supply of the main coil of the AVF cyclotron was exchanged to new one. The old DCCTs (zero-flux current transformers) used for the power supplies of the trim coils of the AVF cyclotron were changed to new DCCTs to get more stability. The potentiometers used for the reference voltages in the other power supplies of the AVF cyclotron and the transport system were changed to the temperature controlled DAC method for numerical-value settings. This paper presents the results of the improvements. (author)

Heat shrink formation of a corrugated thin film thermoelectric generator

International Nuclear Information System (INIS)

Sun, Tianlei; Peavey, Jennifer L.; David Shelby, M.; Ferguson, Scott; O’Connor, Brendan T.

2015-01-01

Highlights: • Demonstrate and characterize a thermoelectric generator with a corrugated geometry. • Employ a novel heat shrink fabrication approach compatible with low-cost processing. • Use thermal impedance modeling to explore design potential. • Corrugated design shown to be advantageous for low heat-flux density applications. - Abstract: A thin film thermoelectric (TE) generator with a corrugated architecture is demonstrated formed using a heat-shrink fabrication approach. Fabrication of the corrugated TE structure consists of depositing thin film thermoelectric elements onto a planar non-shrink polyimide substrate that is then sandwiched between two uniaxial stretch-oriented co-polyester (PET) films. The heat shrink PET films are adhered to the polyimide in select locations, such that when the structure is placed in a high temperature environment, the outer films shrink resulting in a corrugated core film and thermoelectric elements spanning between the outer PET films. The module has a cross-plane heat transfer architecture similar to a conventional bulk TE module, but with heat transfer in the plane of the thin film thermoelectric elements, which assists in maintaining a significant temperature difference across the thermoelectric junctions. In this demonstration, Ag and Ni films are used as the thermoelectric elements and a Seebeck coefficient of 14 μV K −1 is measured with a maximum power output of 0.22 nW per couple at a temperature difference of 7.0 K. We then theoretically consider the performance of this device architecture with high performance thermoelectric materials in the heat sink limited regime. The results show that the heat-shrink approach is a simple fabrication method that may be advantageous in large-area, low power density applications. The fabrication method is also compatible with simple geometric modification to achieve various form factors and power densities to customize the TE generator for a range of applications

Graphene-based copper oxide thin film nanostructures as high-efficiency photocathode for p-type dye-sensitized solar cells

Science.gov (United States)

Kilic, Bayram; Turkdogan, Sunay; Astam, Aykut; Baran, Sümeyra Seniha; Asgin, Mansur; Cebeci, Hulya; Urk, Deniz

2017-10-01

Graphene-based p-type dye-sensitized solar cells (p-DSSCs) have been proposed and fabricated using copper oxide urchin-like nanostructures (COUN) as photocathode with an FeS2 counter electrode (CE). COUN composed of Cu2O core sphere and CuO shell nanorods with overall diameters of 2 to 4 μm were grown by a simple hydrothermal method with self-assemble nucleation. It was figured out that the formation of copper oxide core/shell structures could be adjusted by an ammonia additive leading to pH change of the precursor solution. In addition to a photocathode, we also demonstrated FeS2 thin films as an efficient CE material alternative to the conventional Pt CEs in DSSCs. FeS2 nanostructures, with diameters of 50 to 80 nm, were synthesized by a similar hydrothermal approach. FeS2 nanostructures are demonstrated to be an outstanding CE material in p-DSSCs. We report graphene/COUN as photocathode and Pt/FeS2 as CE in p-DSSCs, and results show that the synergetic combination of electrodes in each side (increased interconnectivity between COUN and graphene layer, high surface area, and high catalytic activity of FeS2) increased the power conversion efficiency from 1.56% to 3.14%. The excellent performances of COUN and FeS2 thin film in working and CEs, respectively, make them unique choices among the various photocathode and CE materials studied.

Automated System Tests High-Power MOSFET's

Science.gov (United States)

Huston, Steven W.; Wendt, Isabel O.

1994-01-01

Computer-controlled system tests metal-oxide/semiconductor field-effect transistors (MOSFET's) at high voltages and currents. Measures seven parameters characterizing performance of MOSFET, with view toward obtaining early indication MOSFET defective. Use of test system prior to installation of power MOSFET in high-power circuit saves time and money.

Growth of high quality large area MgB2 thin films by reactive evaporation

OpenAIRE

Moeckly, Brian H.; Ruby, Ward S.

2006-01-01

We report a new in-situ reactive deposition thin film growth technique for the production of MgB2 thin films which offers several advantages over all existing methods and is the first deposition method to enable the production of high-quality MgB2 films for real-world applications. We have used this growth method, which incorporates a rotating pocket heater, to deposit MgB2 films on a variety of substrates, including single-crystalline, polycrystalline, metallic, and semiconductor materials u...

Preparation of InSe Thin Films by Thermal Evaporation Method and Their Characterization: Structural, Optical, and Thermoelectrical Properties

Directory of Open Access Journals (Sweden)

Sarita Boolchandani

2018-01-01

Full Text Available The indium selenium (InSe bilayer thin films of various thickness ratios, InxSe(1-x (x = 0.25, 0.50, 0.75, were deposited on a glass substrate keeping overall the same thickness of 2500 Ǻ using thermal evaporation method under high vacuum atmosphere. Electrical, optical, and structural properties of these bilayer thin films have been compared before and after thermal annealing at different temperatures. The structural and morphological characterization was done using XRD and SEM, respectively. The optical bandgap of these thin films has been calculated by Tauc’s relation that varies within the range of 1.99 to 2.05 eV. A simple low-cost thermoelectrical power measurement setup is designed which can measure the Seebeck coefficient “S” in the vacuum with temperature variation. The setup temperature variation is up to 70°C. This setup contains a Peltier device TEC1-12715 which is kept between two copper plates that act as a reference metal. Also, in the present work, the thermoelectric power of indium selenide (InSe and aluminum selenide (AlSe bilayer thin films prepared and annealed in the same way is calculated. The thermoelectric power has been measured by estimating the Seebeck coefficient for InSe and AlSe bilayer thin films. It was observed that the Seebeck coefficient is negative for InSe and AlSe thin films.

Thin Film Microbatteries

International Nuclear Information System (INIS)

Dudney, Nancy J.

2008-01-01

aerosol spray coating, for one or more components of the battery. The active materials used for the thin film cathodes and anodes are familiar intercalation compounds, but the microstructures and often the cycling properties of the thin films may be quite distinct from those of battery electrodes formed from powders. The thin film cathodes are dense and homogeneous with no added phases such as binders or electrolytes. When deposited at ambient temperatures, the films of cathodes, such as LiCoO 2 , V 2 O 5 , LiMn 2 O4 , LiFePO 4 are amorphous or nanocrystalline. But even in this form, they often act as excellent cathodes with large specific capacities and good stability for hundreds to thousands of cycles. Annealing the cathode films at temperatures of 300 to 800 C may be used to induce crystallization and grain growth of the desired intercalation compound. Crystallizing the cathode film generally improves the Li chemical diffusivity in the electrode material, and hence the power delivered by the battery, by 1-2 orders of magnitude. The microstructure is also tailored by the deposition and heat treatment. Figure 3 shows a fracture edge of an annealed LiCoO 2 cathode film on an alumina substrate. The columnar microstructure, which is typical of a vapor deposited film, sinters at high temperatures leaving small fissures between the dense columns. Such crystalline films also may have a preferred crystallographic orientation. For LiCoO 2 films the crystallographic texture differs for films deposited by sputtering versus pulse laser ablation processes. To improve the manufacturability of the thin film batteries, it would be beneficial to eliminate or minimize the temperature or duration of the annealing step. Several efforts have lead to low temperature fabrication of thin film batteries on polyimide substrates, but the battery capacity and rate are lower than those treated at high temperatures. For the battery anode, many designs use a vapor-deposited metallic lithium film as

Azaisoindigo conjugated polymers for high performance n-type and ambipolar thin film transistor applications

KAUST Repository

Yue, Wan

2016-09-28

Two new alternating copolymers, PAIIDBT and PAIIDSe have been prepared by incorporating a highly electron deficient azaisoindigo core. The molecular structure and packing of the monomer is determined from the single crystal X-ray diffraction. Both polymers exhibit high EAs and highly planar polymer backbones. When polymers are used as the semiconducting channel for solution-processed thin film transistor application, good properties are observed. A–A type PAIIDBT exhibits unipolar electron mobility as high as 1.0 cm2 V−1 s−1, D–A type PAIIDSe exhibits ambipolar charge transport behavior with predominately electron mobility up to 0.5 cm2 V−1 s−1 and hole mobility to 0.2 cm2 V−1 s−1. The robustness of the extracted mobility values are also commented on in detail. Molecular orientation, thin film morphology and energetic disorder of both polymers are systematically investigated.

Transparent, high mobility InGaZnO thin films deposited by PLD

International Nuclear Information System (INIS)

Suresh, Arun; Gollakota, Praveen; Wellenius, Patrick; Dhawan, Anuj; Muth, John F.

2008-01-01

Transparent oxide semiconductor, InGaZnO, thin films were prepared by pulsed laser deposition at room temperature. The carrier concentration was found to vary by several orders of magnitude from insulating to 10 19 carriers/cm 3 depending on the oxygen partial pressure during deposition. Hall mobilities as high as 16 cm 2 /V s were observed. This is approximately an order of magnitude higher than the mobility of amorphous silicon and indicates that InGaO 3 (ZnO) x with x ≤ 5 may be suitable for transparent, thin film transistor applications. Post-deposition annealing was found to strongly influence the carrier concentration while annealing effects on the electron mobility was less influential

High-frequency Lamb wave device composed of MEMS structure using LiNbO3 thin film and air gap.

Science.gov (United States)

Kadota, Michio; Ogami, Takashi; Yamamoto, Kansho; Tochishita, Hikari; Negoro, Yasuhiro

2010-11-01

High-frequency devices operating at 3 GHz or higher are required, for instance, for future 4th generation mobile phone systems in Japan. Using a substrate with a high acoustic velocity is one method to realize a high-frequency acoustic or elastic device. A Lamb wave has a high velocity when the substrate thickness is thin. To realize a high-frequency device operating at 3 GHz or higher using a Lamb wave, a very thin (less than 0.5 μm thick) single-crystal plate must be used. It is difficult to fabricate such a very thin single crystal plate. The authors have attempted to use a c-axis orientated epitaxial LiNbO(3) thin film deposited by a chemical vapor deposition system (CVD) instead of using a thin LiNbO(3) single crystal plate. Lamb wave resonators composed of a interdigital transducer (IDT)/the LiNbO(3) film/air gap/base substrate structure like micro-electromechanical system (MEMS) transducers were fabricated. These resonators have shown a high frequency of 4.5 and 6.3 GHz, which correspond to very high acoustic velocities of 14,000 and 12,500 m/s, respectively, have excellent characteristics such as a ratio of resonant and antiresonant impedance of 52 and 38 dB and a wide band of 7.2% and 3.7%, respectively, and do not have spurious responses caused by the 0th modes of shear horizontal (SH(0)) and symmetric (S(0)) modes.

Junctionless Thin-Film Transistors Gated by an H₃PO₄-Incorporated Chitosan Proton Conductor.

Science.gov (United States)

Liu, Huixuan; Xun, Damao

2018-04-01

We fabricated an H3PO4-incorporated chitosan proton conductor film that exhibited the electric double layer effect and showed a high specific capacitance of 4.42 μF/cm2. Transparent indium tin oxide thin-film transistors gated by H3PO4-incorporated chitosan films were fabricated by sputtering through a shadow mask. The operating voltage was as low as 1.2 V because of the high specific capacitance of the H3PO4-incorporated chitosan dielectrics. The junctionless transparent indium tin oxide thin film transistors exhibited good performance, including an estimated current on/off ratio and field-effect mobility of 1.2 × 106 and 6.63 cm2V-1s-1, respectively. These low-voltage thin-film electric-double-layer transistors gated by H3PO4-incorporated chitosan are promising for next generation battery-powered "see-through" portable sensors.

On the improvement of PEC activity of hematite thin films deposited by high-power pulsed magnetron sputtering method

Czech Academy of Sciences Publication Activity Database

Kment, Š.; Hubička, Zdeněk; Krysa, C.; Sekora, D.; Zlámal, M.; Olejníček, Jiří; Čada, Martin; Kšírová, Petra; Remeš, Zdeněk; Schmuki, P.; Schubert, E.; Zbořil, R.

2015-01-01

Roč. 165, Apr (2015), s. 344-350 ISSN 0926-3373 R&D Projects: GA ČR GAP108/12/2104; GA MŠk LH12043 Institutional support: RVO:68378271 Keywords : ALD * HiPIMS * passivation layer * photoelectrochemical water splitting * very thin films Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 8.328, year: 2015

High performance thin layer chromatography profile of Cassytha filiformis

Institute of Scientific and Technical Information of China (English)

Mythili Sathiavelu; Sathiavelu Arunachalam

2012-01-01

Objective: To study the phenols, flavonoids, saponin profile of the medicinal plant Cassytha filiformis (C. filiformis) using high performance thin layer chromatography (HPTLC). Methods:The extracts were tested to determine the presence of various phytochmeicals like alkaloids, phenolic compounds, flavonoids, carbohydrates, glycosides, saponins, terpenoids, tannins, fixed oils, fats and protein and aminoacids (Harborne and Harborne, 1998). HPTLC studies were carried out by Harborne and Wagner et al method. Different compositions of the mobile phase for HPTLC analysis were tested in order to obtain high resolution and reproducible peaks. Results: The results of the preliminary phytochemical studies confirm the presence of phenols, alkaloids, carbohydrates, saponins, flavanoids, terpenoids and tannins in the methanolic extracts of C. filiformis. The methanolic extracts of C. filiformis displayed the presence of 13 types of phenolic substances with 13 different Rf values ranging from 0.01 to 0.96. The results illustrated the presence of 9 different types of flavonoides with 9 different Rf values ranging from 0.01 to 0.97. The results of HPTLC analysis of saponins demonstrated the presence of 11 different types of saponins with 11 different Rf values ranging from 0.04 to 0.92. Conclusions: In the present study we observed the phenols, flavonoids, saponin profile of the medicinal plant C. filiformis using high performance thin layer chromatography (HPTLC). Hence it was concluded that the phenolic compounds present in the methonolic extract could be responsible for antioxidant activities. Plant derived antioxidants, especially phenols and flavonoids, have been described to have various properties like anticancer, antiaging and prevention of cardiovascular diseases. Furthur, separation and characterization of the bioactive compound from the plant is to be evaluated and reported in near future.

Proton Radiography with CR-39 by Using the Protons from High Power Femto-second Laser System

International Nuclear Information System (INIS)

Choi, Chang Il; Lee, Dong Hoon; Kang, Byoung Hwi; Kim, Yong Kyun; Choi, Il Woo; Ko, Do Kyeong; Lee, Jong Min

2008-01-01

Proton radiography techniques are useful to obtain a high quality image of a thin object, because protons travel straight in matter. Generation of the high energy proton using conventional accelerator costs high and requires large accelerating facility. But proton radiography using high power femto-second(10-15 second) laser has been interested, because it can generate high energy protons at lower price than the conventional accelerator like a cyclotron. For this study, we used the CR-39 SSNTD (Solid State Nuclear Track Detector) as the proton radiography screen. Commonly, CR-39 is used to detect the tracks of energetic charged particles. Incident energetic charged particles left latent tracks in the CR-39, in the form of broken molecular chains and free radicals. These latent tracks show high chemical reactivity. After chemical etching with the caustic alkali solution such as NaOH or KOH, tracks are appeared to forms of hole. If protons with various energies enter the two targets with another thickness, number of protons passed through the target per unit area is different each other. Using this feature of protons, we can a proton radiographic image with CR-39. We studied proton radiography with CR-39 by using energetic protons from high power femto-second laser and evaluated potentiality of femto-second laser as new energetic proton generator for radiography

Proton probing of ultra-thin foil dynamics in high intensity regime

Science.gov (United States)

Prasad, Rajendra; Aktan, Esin; Aurand, Bastian; Cerchez, Mirela; Willi, Oswald

2017-10-01

The field of laser driven ion acceleration has been enriched significantly over the past decade, thanks to the advanced laser technologies. Already, from 100s TW class systems, laser driven sources of particles and radiations are being considered in number of potential applications in science and medicine due to their unique properties. New physical effects unearthed at these systems may help understand and conduct successful experiments at several PW class multi-beam facilities with high rep rate systems, e.g. ELI. Here we present the first experimental results on ultra-thin foil dynamics irradiated by an ultra-high intensity (1020 W/cm2) , ultra-high contrast (10-12) laser pulse at ARCTURUS laser facility at HHU Duesseldorf. By employing the elegant proton probing technique it is observed that for the circular polarization of laser light, a 100nm thin target is pushed forward as a compressed layer due to the radiation pressure of light. Whereas, the linear polarization seems to decompress the target drastically. 2D particle-in-cell simulations corroborate the experimental findings. Our results confirm the previous simulation studies investigating the fundamental role played by light polarization, finite focus spot size effect and eventually electron heating including the oblique incidence at the target edges.

Enhancement of absorption and color contrast in ultra-thin highly absorbing optical coatings

Science.gov (United States)

Kats, Mikhail A.; Byrnes, Steven J.; Blanchard, Romain; Kolle, Mathias; Genevet, Patrice; Aizenberg, Joanna; Capasso, Federico

2013-09-01

Recently a new class of optical interference coatings was introduced which comprises ultra-thin, highly absorbing dielectric layers on metal substrates. We show that these lossy coatings can be augmented by an additional transparent subwavelength layer. We fabricated a sample comprising a gold substrate, an ultra-thin film of germanium with a thickness gradient, and several alumina films. The experimental reflectivity spectra showed that the additional alumina layer increases the color range that can be obtained, in agreement with calculations. More generally, this transparent layer can be used to enhance optical absorption, protect against erosion, or as a transparent electrode for optoelectronic devices.

Third-order optical susceptibility in polythiophene thin films prepared by spin-coating from high-boiling-point solvents

International Nuclear Information System (INIS)

Kobayashi, Takashi; Shinke, Wataru; Nagase, Takashi; Murakami, Shuichi; Naito, Hiroyoshi

2014-01-01

We examined the enhancements in the third-order optical susceptibility (χ (3) ) of spin-coated thin films of poly(3-hexylthiophene) using an anhydrous solvent with a high boiling point. The χ (3) value was found to be enhanced as the boiling point of the solvent increased. In this study, the largest value of χ (3) was obtained for thin films that were spin-coated in an inert atmosphere using anhydrous dichlorobenzene and then was subsequently exposed to its vapor for 1 h. The maximum value of the imaginary part of χ (3) was determined to be 1.8 × 10 -9 esu, which is more than three times greater than that of thin films spin-coated in an ambient atmosphere using a solvent with a low boiling point, such as chloroform. - Highlights: • Enhancements in nonlinear optical properties of a conjugated polymer were examined. • Thin films were fabricated by spin-coating using a solvent with a high boiling point. • The third-order optical susceptibility increased with increasing boiling point. • An additional enhancement was obtained by the vapor-treatment technique. • These thin films were sufficiently homogeneous for use in nonlinear optical devices

Application of parallel connected power-MOSFET elements to high current d.c. power supply

International Nuclear Information System (INIS)

Matsukawa, Tatsuya; Shioyama, Masanori; Shimada, Katsuhiro; Takaku, Taku; Neumeyer, Charles; Tsuji-Iio, Shunji; Shimada, Ryuichi

2001-01-01

The low aspect ratio spherical torus (ST), which has single turn toroidal field coil, requires the extremely high d.c. current like as 20 MA to energize the coil. Considering the ratings of such extremely high current and low voltage, power-MOSFET element is employed as the switching device for the a.c./d.c. converter of power supply. One of the advantages of power-MOSFET element is low on-state resistance, which is to meet the high current and low voltage operation. Recently, the capacity of power-MOSFET element has been increased and its on-state resistance has been decreased, so that the possibility of construction of high current and low voltage a.c./d.c. converter with parallel connected power-MOSFET elements has been growing. With the aim of developing the high current d.c. power supply using power-MOSFET, the basic characteristics of parallel operation with power-MOSFET elements are experimentally investigated. And, the synchronous rectifier type and the bi-directional self commutated type a.c./d.c. converters using parallel connected power-MOSFET elements are proposed

Highly-stabilized power supply for synchrotron accelerators. High speed, low ripple power supply

Energy Technology Data Exchange (ETDEWEB)

Sato, Kenji [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Kumada, Masayuki; Fukami, Kenji; Koseki, Shoichiro; Kubo, Hiroshi; Kanazawa, Toru

1997-02-01

In synchrotron accelerators, in order to utilize high energy beam effectively, those are operated by repeating acceleration and taking-out at short period. In order to accelerate by maintaining beam track stable, the tracking performance with the error less than 10{sup -3} in the follow-up of current is required for the power supply. Further, in order to maintain the intensity and uniformity of beam when it is taken out, very low ripple is required for output current. The power supply having such characteristics has been developed, and applied to the HIMAC and the SPring-8. As the examples of the application of synchrotrons, the accelerators for medical treatment and the generation of synchrotron radiation are described. As to the power supply for the deflection magnets and quadrupole magnets of synchrotron accelerators, the specifications of the main power supply, the method of reducing ripple, the method of improving tracking, and active filter control are reported. As to the test results, the measurement of current ripple and tracking error is shown. The lowering of ripple was enabled by common mode filter and the symmetrical connection of electromagnets, and high speed response was realized by the compensation for delay with active filter. (K.I.)

Highly conductive grain boundaries in copper oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Deuermeier, Jonas, E-mail: j.deuermeier@campus.fct.unl.pt [Department of Materials Science, Faculty of Science and Technology, i3N/CENIMAT, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica (Portugal); Department of Materials and Earth Sciences, Technische Universität Darmstadt, Jovanka-Bontschits-Straße 2, D-64287 Darmstadt (Germany); Wardenga, Hans F.; Morasch, Jan; Siol, Sebastian; Klein, Andreas, E-mail: aklein@surface.tu-darmstadt.de [Department of Materials and Earth Sciences, Technische Universität Darmstadt, Jovanka-Bontschits-Straße 2, D-64287 Darmstadt (Germany); Nandy, Suman; Calmeiro, Tomás; Martins, Rodrigo; Fortunato, Elvira [Department of Materials Science, Faculty of Science and Technology, i3N/CENIMAT, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica (Portugal)

2016-06-21

High conductivity in the off-state and low field-effect mobility compared to bulk properties is widely observed in the p-type thin-film transistors of Cu{sub 2}O, especially when processed at moderate temperature. This work presents results from in situ conductance measurements at thicknesses from sub-nm to around 250 nm with parallel X-ray photoelectron spectroscopy. An enhanced conductivity at low thickness is explained by the occurrence of Cu(II), which is segregated in the grain boundary and locally causes a conductivity similar to CuO, although the surface of the thick film has Cu{sub 2}O stoichiometry. Since grains grow with an increasing film thickness, the effect of an apparent oxygen excess is most pronounced in vicinity to the substrate interface. Electrical properties of Cu{sub 2}O grains are at least partially short-circuited by this effect. The study focuses on properties inherent to copper oxide, although interface effects cannot be ruled out. This non-destructive, bottom-up analysis reveals phenomena which are commonly not observable after device fabrication, but clearly dominate electrical properties of polycrystalline thin films.

Development of nanocrystalline Indium Tin Oxide (ITO) thin films using RF-magnetron sputtering

International Nuclear Information System (INIS)

Tamilselvan, N.; Thilakan, Periyasamy

2013-01-01

ITO thin films have been deposited on glass substrate using RF Magnetron puttering Technique from the pre-synthesized ITO target. The sputtering parameters such as the deposition temperature, gas composition and the RF power densities were varied. X-ray diffraction studies revealed that the crystallization of the films is mostly depending on the RF power density and substrate temperature. Crystallized films exhibited a change in the preferred orientation from (111) plane to (100) plane at specific conditions such as high RF power density and high oxygen mixing to the plasma. Change in the film microstructure and a shift in the optical bandgap were recorded from the SEM and UV-Visible measurements respectively. (author)

In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

International Nuclear Information System (INIS)

Zhao, J.; Noh, D.W.; Chern, C.; Li, Y.Q.; Norris, P.E.; Kear, B.; Gallois, B.

1991-01-01

Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology

Reactor G1: high power experiments

International Nuclear Information System (INIS)

Laage, F. de; Teste du Baillet, A.; Veyssiere, A.; Wanner, G.

1957-01-01

The experiments carried out in the starting-up programme of the reactor G1 comprised a series of tests at high power, which allowed the following points to be studied: 1- Effect of poisoning by Xenon (absolute value, evolution). 2- Temperature coefficients of the uranium and graphite for a temperature distribution corresponding to heating by fission. 3- Effect of the pressure (due to the coiling system) on the reactivity. 4- Calibration of the security rods as a function of their position in the pile (1). 5- Temperature distribution of the graphite, the sheathing, the uranium and the air leaving the canals, in a pile running normally at high power. 6- Neutron flux distribution in a pile running normally at high power. 7- Determination of the power by nuclear and thermodynamic methods. These experiments have been carried out under two very different pile conditions. From the 1. to the 15. of August 1956, a series of power increases, followed by periods of stabilisation, were induced in a pile containing uranium only, in 457 canals, amounting to about 34 tons of fuel. A knowledge of the efficiency of the control rods in such a pile has made it possible to measure with good accuracy the principal effects at high temperatures, that is, to deal with points 1, 2, 3, 5. Flux charts giving information on the variations of the material Laplacian and extrapolation lengths in the reflector have been drawn up. Finally the thermodynamic power has been measured under good conditions, in spite of some installation difficulties. On September 16, the pile had its final charge of 100 tons. All the canals were loaded, 1,234 with uranium and 53 (i.e. exactly 4 per cent of the total number) with thorium uniformly distributed in a square lattice of 100 cm side. Since technical difficulties prevented the calibration of the control rods, the measurements were limited to the determination of the thermodynamic power and the temperature distributions (points 5 and 7). This report will

Initial results for a 170 GHz high power ITER waveguide component test stand

Science.gov (United States)

Bigelow, Timothy; Barker, Alan; Dukes, Carl; Killough, Stephen; Kaufman, Michael; White, John; Bell, Gary; Hanson, Greg; Rasmussen, Dave

2014-10-01

A high power microwave test stand is being setup at ORNL to enable prototype testing of 170 GHz cw waveguide components being developed for the ITER ECH system. The ITER ECH system will utilize 63.5 mm diameter evacuated corrugated waveguide and will have 24 >150 m long runs. A 170 GHz 1 MW class gyrotron is being developed by Communications and Power Industries and is nearing completion. A HVDC power supply, water-cooling and control system has been partially tested in preparation for arrival of the gyrotron. The power supply and water-cooling system are being designed to operate for >3600 second pulses to simulate the operating conditions planned for the ITER ECH system. The gyrotron Gaussian beam output has a single mirror for focusing into a 63.5 mm corrugated waveguide in the vertical plane. The output beam and mirror are enclosed in an evacuated duct with absorber for stray radiation. Beam alignment with the waveguide is a critical task so a combination of mirror tilt adjustments and a bellows for offsets will be provided. Analysis of thermal patterns on thin witness plates will provide gyrotron mode purity and waveguide coupling efficiency data. Pre-prototype waveguide components and two dummy loads are available for initial operational testing of the gyrotron. ORNL is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under Contract DE-AC-05-00OR22725.

Improvement of CH3NH3PbI3 thin film using the additive 1,8-diiodooctane for planar heterojunction perovskite cells

Science.gov (United States)

Abdulrahman, Solh; Wang, Chunhua; Cao, Chenghao; Zhang, Chujun; Yang, Junliang; Jiang, Li

2017-10-01

The thin-film quality is critical for obtaining high-performance perovskite solar cells (PSCs). The additive 1,8-diiodooctane (DIO) was used to control the morphology and structure of CH3NH3PbI3 perovskite thin films, and planar heterojunction (PHJ) PSCs with an architecture of ITO/PEDOT: PSS/CH3NH3PbI3/PCBM/Al was fabricated. It was found that the DIO played an important role on CH3NH3PbI3 thin-film quality and the performance of PHJ-PSCs. With the optimal volume ratio of 2%, the compact and uniform high-quality CH3NH3PbI3 thin films with enhanced crystallinity and less roughness were achieved, resulting in the great improvement of power conversion efficiency (PCE) from about 4.5% to over 9.0%. The research results indicate that the additive DIO is a simple and effective method to produce high-quality perovskite thin film and accordingly develop high-performance PHJ-PSCs.

Thin-slice high-resolution CT study of pulmonary asbestosis and idiopathic interstitial pneumonia

International Nuclear Information System (INIS)

Hatakeyama, Masayuki; Maeda, Munehiro; Ohmura, Takuya

1987-01-01

Thin-slice high-resolution CT findings were compared between 36 patients with pulmonary asbestos exposure (AS) and 33 patients with idiopathic interstitial pneumonia (IIP). The CT scans of these patients were classified into 5 types (0-IV) by the subpleural curvilinear shadow (SCLS) and honey-comb shadow (HS). SCLS was detected in 22 (62 %) patients with AS and 7 (21 %) with IIP. HS was detected in 14 (39 %) patients with AS and 33 (100 %) with IIP. In both the diseases, SCLS was distributed mainly in the lower lobe in CT types I and II, and in mildly fibrotic segments in types III and IV. In CT types II, III and IV, SCLS was always communicated with HS. Thin-slice high-resolution CT is considered very helpful in diagnosis and staging of not only AS and IIP but also pulmonary fibrosis. (author)

Solid phase epitaxial growth of high mobility La:BaSnO_3 thin films co-doped with interstitial hydrogen

International Nuclear Information System (INIS)

Niedermeier, Christian A.; Rhode, Sneha; Fearn, Sarah; Moram, Michelle A.; Ide, Keisuke; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio

2016-01-01

This work presents the solid phase epitaxial growth of high mobility La:BaSnO_3 thin films on SrTiO_3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO_3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm"2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO_3 thin films, and a 9%–16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO_3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO_3 thin films were increased to 3 × 10"1"9" cm"−"3 and in La:BaSnO_3 thin films from 6 × 10"1"9" cm"−"3 to 1.5 × 10"2"0" cm"−"3, supporting a theoretical prediction that interstitial H serves as an excellent n-type dopant. An analysis of the free electron absorption by infrared spectroscopy yields a small (H,La):BaSnO_3 electron effective mass of 0.27 ± 0.05 m_0 and an optical mobility of 26 ± 7 cm"2/Vs. As compared to La:BaSnO_3 single crystals, the smaller electron mobility in epitaxial thin films grown on SrTiO_3 substrates is ascribed to threading dislocations as observed in high resolution transmission electron micrographs.

Development of planar solid oxide fuel cells for power generation applications

Energy Technology Data Exchange (ETDEWEB)

Minh, N.Q. [AlliedSignal Aerospce Equipment Systems, Torrance, CA (United States)

1996-04-01

Planar solid oxide fuel cells (SOFCs) are presently being developed for a variety of electric power generation application. The planar design offers simple cell geometry, high power density, and multiple fabrication and gas manifolding options. Planar SOFC technology has received much attention recently, and significant progress has been made in this area. Recent effort at AlliedSignal has focused on the development of high-performance, lightweight planar SOFCs, having thin-electrolyte films, that can be operated efficiently at reduced temperatures (< 1000{degrees}C). The advantages of reduced-temperature operation include wider material choice (including use of metallic interconnects), expected longer cell life, reduced thermal stress, improved reliability, and reduced fuel cell cost. The key aspect in the development of thin-film SIFCs is to incorporate the thin electrolyte layer into the desired structure of cells in a manner that yields the required characteristics. AlliedSignal has developed a simple and cost-effective method based on tape calendering for the fabrication of thin-electrolyte SOFCs. Thin-electrolyte cells made by tape calendering have shown extraordinary performance, e.g., producing more than 500mW/cm{sup 2} at 700{degrees}C and 800mW/cm{sup 2} at 800{degrees}C with hydrogen as fuel and air is oxidant. thin-electrolyte single cells have been incorporated into a compliant metallic stack structure and operated at reduced and operated at reduced-temperature conditions.

Calculation of mass transfer in the remote cutting of metals by radiation of a high-power repetitively pulsed CO2 laser

International Nuclear Information System (INIS)

Gladush, G G; Rodionov, N B

2002-01-01

The mechanism of remote cutting of steel plates by radiation of a high-power repetitively pulsed CO 2 laser is theoretically studied. The models of melt removal by the gravity force and the recoil pressure of material vapour are proposed and the sufficient conditions for the initiation of cutting are determined. A numerical model of a thermally thin plate was employed to describe the cutting for large focal spots. (interaction of laser radiation with matter. laser plasma)

Voltage generators of high voltage high power accelerators

International Nuclear Information System (INIS)

Svinin, M.P.

1981-01-01

High voltage electron accelerators are widely used in modern radiation installations for industrial purposes. In the near future further increasing of their power may be effected, which enables to raise the efficiency of the radiation processes known and to master new power-consuming production in industry. Improvement of HV generators by increasing their power and efficiency is one of many scientific and engineering aspects the successful solution of which provides further development of these accelerators and their technical parameters. The subject is discussed in detail. (author)

Optimal Operation of Plug-In Electric Vehicles in Power Systems with High Wind Power Penetrations

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Chen, Zhe

2013-01-01

in the power systems with high wind power penetrations. In this paper, the integration of plug-in electric vehicles in the power systems with high wind power penetrations is proposed and discussed. Optimal operation strategies of PEV in the spot market are proposed in order to decrease the energy cost for PEV......The Danish power system has a large penetration of wind power. The wind fluctuation causes a high variation in the power generation, which must be balanced by other sources. The battery storage based Plug-In Electric Vehicles (PEV) may be a possible solution to balance the wind power variations...... owners. Furthermore, the application of battery storage based aggregated PEV is analyzed as a regulation services provider in the power system with high wind power penetrations. The western Danish power system where the total share of annual wind power production is more than 27% of the electrical energy...

Research & Implementation of AC - DC Converter with High Power Factor & High Efficiency

Directory of Open Access Journals (Sweden)

Hsiou-Hsian Nien

2014-05-01

Full Text Available In this paper, we design and develop a high power factor, high efficiency two-stage AC - DC power converter. This paper proposes a two-stage AC - DC power converter. The first stage is boost active power factor correction circuit. The latter stage is near constant frequency LLC resonant converter. In addition to traditional LLC high efficiency advantages, light-load conversion efficiency of this power converter can be improved. And it possesses high power factor and near constant frequency operating characteristics, can significantly reduce the electromagnetic interference. This paper first discusses the main structure and control manner of power factor correction circuit. And then by the LLC resonant converter equivalent model proceed to circuit analysis to determine the important parameters of the converter circuit elements. Then design a variable frequency resonant tank. The resonant frequency can change automatically on the basis of the load to reach near constant frequency operation and a purpose of high efficiency. Finally, actually design and produce an AC – DC power converter with output of 190W to verify the characteristics and feasibility of this converter. The experimental results show that in a very light load (9.5 W the efficiency is as high as 81%, the highest efficiency of 88% (90 W. Full load efficiency is 87%. At 19 W ~ 190 W power changes, the operating frequency change is only 0.4 kHz (AC 110 V and 0.3 kHz (AC 220 V.

High-Bandwidth, High-Efficiency Envelope Tracking Power Supply for 40W RF Power Amplifier Using Paralleled Bandpass Current Sources

DEFF Research Database (Denmark)

Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

2005-01-01

This paper presents a high-performance power conversion scheme for power supply applications that require very high output voltage slew rates (dV/dt). The concept is to parallel 2 switching bandpass current sources, each optimized for its passband frequency space and the expected load current....... The principle is demonstrated with a power supply, designed for supplying a 40 W linear RF power amplifier for efficient amplification of a 16-QAM modulated data stream...

New high-gain thin-gap detector for the OPAL hadron calorimeter

Energy Technology Data Exchange (ETDEWEB)

Dado, S; Goldberg, J; Lupu, N; Mincer, A I; Alexander, G; Bella, G; Gnat, Y; Grunhaus, J; Levy, A; Cohen, J

1986-12-01

A new type of thin-gap multiwire gas detector operating in a high-gain mode was developed for use in the OPAL pole-tip calorimeter. The detector thickness is only 6.6 mm and its area is 0.61 m/sup 2/. The induced pad readout provides high output pulses that require no amplification. The setup for the detector mass production and quality-control test is described. Results from a test beam setup that simulates the OPAL pole-tip calorimeter are presented and compared with computer simulations.

Small high cooling power space cooler

Energy Technology Data Exchange (ETDEWEB)

Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E. [Northrop Grumman Aerospace Systems Redondo Beach, Ca, 90278 (United States)

2014-01-29

The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

Innovative opto-mechanical design of a laser head for compact thin-disk

Science.gov (United States)

Macúchová, Karolina; Smrž, Martin; Řeháková, Martina; Mocek, Tomáš

2016-11-01

We present recent progress in design of innovative versatile laser head for lasers based on thin-disk architecture which are being constructed at the HiLASE centre of the IOP in the Czech Republic. Concept of thin-disk laser technology allows construction of lasers providing excellent beam quality with high average output power and optical efficiency. Our newly designed thin-disk carrier and pump module comes from optical scheme consisting of a parabolic mirror and roof mirrors proposed in 90's. However, mechanical parts and a cooling system were in-house simplified and tailor-made to medium power lasers since no suitable setup was commercially available. Proposed opto-mechanical design is based on stable yet easily adjustable mechanics. The only water nozzle-cooled component is a room-temperature-operated thindisk mounted on a special cooling finger. Cooling of pump optics was replaced by heat conductive transfer from mirrors made of special Al alloy to a massive brass baseplate. Such mirrors are easy to manufacture and very cheap. Presented laser head was manufactured and tested in construction of Er and Yb doped disk lasers. Details of the latest design will be presented.