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1

Spinal vacuum phenomena: anatomical study and review.  

PubMed

"Vacuum" phenomena relate to the accumulation of gas, principally nitrogen, in crevices within the intervertebral disk or vertebra. Their appearance does not uniformly indicate "degenerative" disk disease (primary intervertebral osteochondrosis), as gaseous collections may accompany other processes (vertebral osteomyelitis, Schmorl node formation, spondylosis deformans, vertebral collapse with osteonecrosis) affecting the disk and adjacent vertebral bodies. The location and appearance of the "vacuum" phenomena are helpful indicators as to the precise nature of the spinal disorder. PMID:7220878

Resnick, D; Niwayama, G; Guerra, J; Vint, V; Usselman, J

1981-05-01

2

Defect reduction of multi-walled carbon nanotubes by rapid vacuum arc annealing  

Microsoft Academic Search

A rapid thermal annealing process using a DC vacuum arc discharge system was shown to reduce defects in carbon nanotubes (CNTs). Multi-walled CNTs (MWCNTs) exhibit high-density structural imperfections when deposited via chemical vapour deposition at relatively low temperatures (650C). These defects can be thermally annealed to reconstruct the graphitic structure. A vacuum arc discharge system was used to anneal the

Jeff T.H. Tsai; Anders A. Tseng

2009-01-01

3

Color center annealing in ? - irradiated polystyrene, under vacuum and air atmospheres  

NASA Astrophysics Data System (ADS)

A primary effect of low doses of ionizing radiation on polystyrene is the production of absorption centers in the UV and Visible regions of the spectrum. There are two types of color centers: "annealable" and "permanent". Annealable centers are most likely due to the formation of cyclohexadienyl, radicals in the polymer. These species have not only strong UV absorption bands (largely obscured by the parent polystyrene absorption) but also weak visible absorptions above 420nm. Post-irradiation annealing has been associated with diffusion of O 2 into the solid polymer sample. We now find that annealing can also occur in the absence of oxygen. These two annealing mechanisms can be understood in terms of colored free radicals, trapped within the irradiated solid matrix, which form colorless products upon reaction with O 2 or reaction with other (nearby) radicals. The rate of ambient temperature annealing in vacuum is drastically slower than in air. Annealing rates increase significantly with increasing temperature, particularly in vacuum where annealing times under ambient conditions are on the order of months or years, compared with several days at 80C. In all cases, samples which were irradiated in vacuum and subsequently exposed to air, developed sharp annealing fronts. Front movement rates were found to be dose-dependent with an apparent saturation effect occuring at the high end of the dose range. Analyses of the front movements allowed estimates to be made of the oxygen consumed during the annealing process.

Wallace, J. S.; Sinclair, M. B.; Gillen, K. T.; Clough, R. L.

1993-01-01

4

Electrochromism of annealed vacuum-evaporated V 2O 5 films  

Microsoft Academic Search

The stability of vacuum-evaporated V2O5 films in electrolyte solutions was greatly enhanced when the films were annealed at 400 or 500C for 1.5 h. The electrochromic performance of the annealed films also showed improvements over unannealed samples.

Z. S. Guan; J. N. Yao; Y. A. Yang; B. H. Loo

1998-01-01

5

Tribological behavior of RF sputtering WS2 thin films with vacuum annealing  

NASA Astrophysics Data System (ADS)

Thin films of tungsten disulfide (WS2) were deposited on 3Cr13 martensitic stain less steel substrate by RF sputtering. The as-deposited films were annealed at 200,400 and 600 C for 2 h in vacuum. The vacuum degree was 510-4 Pa. Composition, surface morphology, structure properties and tribological behavior were studied by EDS, SEM, X-ray diffraction techniques and tribometer, respectively. At 200 C, the films showed low crystallization structure and the tribological behavior was not improved obviously. But at 400 C, the films tribological behavior were improved obviously and non-crystalline to hexagonal structural transition appeared. When annealing temperature rose to 600 C, the films were desquamated from substrate. The results suggested that suitable vacuum annealing was able to promote crystallization and improve tribological performance of RF sputtering WS2 films.

Guangyu, Du; Dechun, Ba; Zhen, Tan; Kun, Liu

6

Vacuum annealing effects on properties of ITO films prepared by reactive low voltage ion plating technique  

NASA Astrophysics Data System (ADS)

With reactive low voltage ion plating technique, ITO (indium oxide doped with tin) films were deposited on glass substrates by using ITO pellet with a composition of 90 wt.% In2O3 and 10 wt.% SnO2 without extra heating. The post annealing process was done in vacuum with different annealing temperature at 100, 200, 300 and 400C for 2 hours, respectively. The effects of vacuum annealing on structural, optical and electrical properties of the ITO film deposited by RLVIP were studied in detail. The results showed that the crystalline of the film was improved with the higher temperature. The increase of the annealing temperature improved the infrared reflectivity from 30% to 80% over 8~14?m of the infrared atmosphere window, and a simultaneous variation in the optical transmission of the visible spectral region occurred. In addition, sheet resistance of ITO films had contrary changing trend with the IR reflectance, as well.

Xu, Ying; Gao, Jinsong; Zheng, Xuanming; Wang, Xiaoyi; Wang, Tongtong; Chen, Hong

2005-12-01

7

Vacuum annealing effects on properties of ITO films prepared by reactive low voltage ion plating technique  

Microsoft Academic Search

With reactive low voltage ion plating technique, ITO (indium oxide doped with tin) films were deposited on glass substrates by using ITO pellet with a composition of 90 wt.% In2O3 and 10 wt.% SnO2 without extra heating. The post annealing process was done in vacuum with different annealing temperature at 100, 200, 300 and 400C for 2 hours, respectively. The

Ying Xu; Jinsong Gao; Xuanming Zheng; Xiaoyi Wang; Tongtong Wang; Hong Chen

2005-01-01

8

Work function recovery of air exposed molybdenum oxide thin films with vacuum annealing  

NASA Astrophysics Data System (ADS)

We report substantial work function (WF) recovery of air exposed molybdenum oxide thin films with vacuum annealing. The high WF (6.8 eV) of thermally evaporated MoOx thin film was observed to decrease sharply to 5.6 eV with an air exposure of one hour. The drop in the WF was accompanied with a very thin layer of oxygen rich adsorbate on the MoOx film. The WF of the exposed MoOx film started to gradually recover with increasing annealing temperature in a vacuum chamber having base pressure of 8 x 10-11 torr. The saturation in the WF recovery was observed around 460 ^oC, with WF 6.4 eV. The adsorb layer was found to be removed after the vacuum annealing. We further studied the interface formation between the annealed MoOx and copper pthalocynine (CuPc). The highest occupied molecular orbital (HOMO) level of CuPc was observed to be almost pinned to the Fermi level, strongly suggesting an efficient hole injection through the vacuum annealed MoOx film.

Irfan, Irfan; Turniske, Alexander; Bao, Zhenan; Gao, Yongli

2012-02-01

9

Surface enhanced Raman scattering of aged graphene: Effects of annealing in vacuum  

SciTech Connect

In this paper, we report a simple method to recover the surface enhanced Raman scattering activity of aged graphene. The Raman signals of Rhodamine molecules absorbed on aged graphene are dramatically increased after vacuum annealing and comparable to those on fresh graphene. Atomic force microscopy measurements indicate that residues on aged graphene surface can efficiently be removed by vacuum annealing, which makes target molecule closely contact with graphene. We also find that the hole doping in graphene will facilitate charge transfer between graphene and molecule. These results confirm the strong Raman enhancement of target molecule absorbed on graphene is due to the charge transfer mechanism.

Wang Yingying; Li Aizhi; Qu Shiliang [Department of Optoelectronic Science, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Ni Zhenhua; Zafar, Zainab; Qiu Teng [Department of Physics, Southeast University, Nanjing 211189 (China); Zhang Yan; Ni Zhonghua [Jiangsu Key Laboratory for Design and Fabrication of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Yu Ting; Shen Zexiang [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore)

2011-12-05

10

Annealing single-walled metallic carbon nanotube devices in ultra-high vacuum  

Microsoft Academic Search

Single walled carbon nanotube (SWNT) devices were fabricated and annealed in ultra high vacuum (UHV) with simultaneous electrical characterization. As one-dimensional crystals with nanometer scale diameters and up to meter scale lengths, SWNTs offer a unique opportunity to probe 1D transport in mesoscopic electronics. Furthermore, all of the atoms in SWNTs are surface atoms which means that the electronic properties

Alexander Allen Kane

2010-01-01

11

Stability of zirconium silicate films on Si under vacuum and O2 annealing  

Microsoft Academic Search

The effect of postdeposition annealing in vacuum and in dry O2 on the atomic transport and chemical stability of chemical vapor deposited ZrSixOy films on Si is investigated. Rutherford backscattering spectrometry, narrow nuclear resonance profiling, and low energy ion scattering spectroscopy were used to obtain depth distributions of Si, O, and Zr in the films. The chemical environment of these

J. Morais; E. B. O. da Rosa; L. Miotti; R. P. Pezzi; I. J. R. Baumvol; A. L. P. Rotondaro; M. J. Bevan; L. Colombo

2001-01-01

12

Mid-Infrared Spectral Evolution of Amorphous Magnesium Silicate Smokes Annealed in Vacuum: Comparison to Cometary Spectra  

Microsoft Academic Search

Amorphous magnesium silicate smokes were prepared by vapor phase condensation and annealed in vacuum. The samples were monitored by IR spectroscopy as a function of annealing time and temperature, focusing on the development of the 10 ?m silicate feature. The IR spectrum of the initial condensate displayed a broad band at 9.3 ?m. After annealing for 10.5 h at 1027

Susan L. Hallenbeck; Joseph A. Nuth; Patricia L. Daukantas

1998-01-01

13

The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles  

Microsoft Academic Search

In order to increase the longevity of contaminant retention, a method is sought to improve the corrosion resistance of iron\\u000a nanoparticles (INP) used for remediation of contaminated water and thereby extend their industrial lifetime. A multi-disciplinary\\u000a approach was used to investigate changes induced by vacuum annealing (?8mbar) at 500C on the bulk and surface chemistry of INP. The particle size

Thomas B. Scott; Michelle Dickinson; Richard A. Crane; Olga Riba; Gareth M. Hughes; Geoffrey C. Allen

2010-01-01

14

Influence of rapid thermal vacuum annealing and high temperature treatment on the properties of PSG films  

NASA Astrophysics Data System (ADS)

The effect is presented of rapid thermal annealing (RTA) in vacuum and thermal annealing in water vapor at 850 C on the properties of phosphosilicate glass (PSG) films deposited in PECVD and ?PCVD reactors. The films were characterized by etch rates and XPS and AES analyses. The RTA was carried out at 800 - 1400 C at annealing times varying from 15 to 180 sec. The RTA caused a significant decrease in the etch rate, which is indicative of structural changes. The XPS and AES analyses showed that the PECVD PSG films contain excess Si due to the lower oxidation activity of N2O. The excess Si can be oxidized in water vapor at high temperatures. The excess Si leads to a decrease in the etching rate of the PECVD PSG layers as compared to that of the ?PCVD films.

Beschkov, G.; Bakardjieva, V.; Alexieva, Z.

2008-05-01

15

STM and XPS characterisation of vacuum annealed nanocrystalline WO 3 films  

NASA Astrophysics Data System (ADS)

Scanning tunnelling microscopy and X-ray Photoelectron Spectroscopy were conducted on magnetron sputtered WO 3 thin films, following a sequence of ultra high vacuum anneals from 100 C to 900 C. Annealing from 100 C to 400 C induced an upward surface band bending of about 0.3 eV, attributed to the oxygen migration from the bulk to the surface, but no changes in the surface topography. Chemical changes occurred from 600 C to 800 C, associated with the formation of secondary oxide species. STM imaging showed that the film surface consists of amorphous particles 35 nm in size up to 600 C, while higher temperatures resulted in an increase in particle size. Crystallisation of the nanoparticles started to occur after annealing at 600 C. The implications in terms of gas sensing are discussed.

Maffeis, T. G. G.; Yung, D.; LePennec, L.; Penny, M. W.; Cobley, R. J.; Comini, E.; Sberveglieri, G.; Wilks, S. P.

2007-11-01

16

HRTEM and Raman characterisation of the onion-like carbon synthesised by annealing detonation nanodiamond at lower temperature and vacuum  

Microsoft Academic Search

Onion-like carbon (OLC) was synthesised by annealing detonation nanodiamond for 1.5?h at temperatures from 500 to 1400C and at a vacuum of 1?Pa. The results showed that the nanodiamond was transformed into the amorphous carbon (a-C) at first and then the a-C was transformed into the OLC gradually with the increase in annealing temperature. Moreover, at the annealing temperature of

Q. Zou; M. Z. Wang; Y. G. Li; B. Lv; Y. C. Zhao

2010-01-01

17

High-vacuum annealing reduction of Co/CoO nanoparticles.  

PubMed

Porous films of Co/CoO magnetic nanoparticles have been obtained by inert gas condensation and partially oxidized in situ in the deposition chamber. These nanoparticle films were subjected to thermal treatments in high vacuum and the chemical and structural changes monitored by x-ray diffraction, transmission electron microscopy, transport and magnetic measurements (with a focus on the exchange-bias phenomenon), which evidence that for vacuum annealing temperatures above 360?C, most of the CoO phase is reduced to metallic Co without requiring the presence of an external reducing agent (e.g., H?) or a plasma. Additionally, there is a certain degree of particle coalescence resulting in the formation of greater nanoparticles as the annealing temperature increases. This yields a smaller proportion of CoO compared to metallic Co and a reduction of the Co/CoO interface density, pinpointed by a drastic decrease of the exchange-bias field. The crucial roles of the vacuum level and the surface-to-volume ratio are evidenced by magnetic measurements, highlighting the potential of magnetometry as a probe for the reduction/oxidation of composite nanostructures. PMID:24532090

Lpez Antn, R; Gonzlez, J A; Andrs, J P; Canales-Vzquez, J; De Toro, J A; Riveiro, J M

2014-03-14

18

Phase Transformation and R-T Characteristics of Vacuum Annealed Vanadium Oxide Thin Films  

NASA Astrophysics Data System (ADS)

Polycrystalline vanadium oxide (VOx) thin films with mixed phases of V6O13 + VO2 (M) are deposited onto p-doped Si (100) substrates at 430C using magnetron sputtering. By vacuum annealing on as-deposited VOx thin films at 450C, at different annealing times we obtained nanoscale polycrystalline VOx thin films with two or more mixed phases. With the annealing time increasing, the phases of the films underwent the following transformation: V6O13 + VO2 (M) ? VO2 (M) + VO2 (B) ? VO2 (B) + VO2 (M) + V5O9 ? V4O7 + V5O9. The surface of VOx thin films prepared in different conditions is of high quality with mean grain size ranging from 80 to 300 nm and the Ra being about 20nm. The lowest temperature coefficient of resistance at ambient temperature (20C) of -2% K-1 is found in the VOx thin film annealed at 450C for 8 h with mixed phases of VO2 (M) + VO2 (B), which can meet the needs of microbolometer materials.

Wang, Y. L.; Li, M. C.; Zhao, L. C.

19

Effect of vacuum annealings on the electronic properties of clean Si(111) surfaces  

NASA Astrophysics Data System (ADS)

Clean cleaved Si(111) samples of various degrees of doping have been vacuum annealed at increasing temperatures, up to 1150 C and studied in situ by photoemission-yield spectroscopy, with low-energy electron-diffraction and Auger-electron-spectroscopy controls. The photoyield-spectrum changes upon annealing of 77 reconstructed surfaces are interpreted as a sharp increase of the density of acceptor levels in the surface layer probed by photoemission. The effect starts above 700 C and saturates beyond 1050 C at (2+/-1)1019 acceptor states cm-3; contamination decreases this p-type overdoping effect. It is attributed to the formation of the appropriate number of Si vacancies, which relaxes, and therefore measures, the residual surface stress of the perfect 77 reconstruction.

Bensalah, S.; Lacharme, J.-P.; Sbenne, C. A.

1991-06-01

20

Low Vacuum Annealing of Cellulose Acetate on Nickel Towards Transparent Conductive CNT-Graphene Hybrid Films.  

PubMed

We report a versatile method based on low vacuum annealing of cellulose acetate on nickel (Ni) surface for rapid fabrication of graphene and carbon nanotube (CNT)-graphene hybrid films with tunable properties. Uniform films mainly composed of tri-layer graphene can be achieved via a surface precipitation of dissociated carbon at 800 C for 30 seconds under vacuum conditions of ?0.6 Pa. The surface precipitation process is further found to be efficient for joining the precipitated graphene with pre-coated CNTs on the Ni surface, consequently, generating the hybrid films. As expected, the hybrid films exhibit substantial opto-electrical and field electron emission properties superior to their individual counterparts. The finding suggests a promising route to hybridize the graphene with diverse nanomaterials for constructing novel hybrid materials with improved performances. PMID:24852931

Nguyen, Duc Dung; Tiwari, Rajanish N; Matsuoka, Yuki; Hashimoto, Goh; Rokuta, Eiji; Chen, Yu-Ze; Chueh, Yu-Lun; Yoshimura, Masamichi

2014-06-25

21

Effect of H2S Annealing on Sb-Doped Cu--In--S Thin Films Prepared by Vacuum Evaporation  

NASA Astrophysics Data System (ADS)

We investigated the effect of H2S annealing on Sb-doped Cu--In--S thin films prepared using a vacuum evaporation method. These CuInS2 thin films were grown successfully when annealed above 350 C in H2S atmosphere. It was found that the thin films were closer to stoichiometry at lower annealing temperatures compared with the undoped thin films. The carrier concentrations, resistivities and mobilities of Sb-doped thin films annealed at 400 C were approximately 1 1018 cm-3, 30 ? cm, and 1 cm2 V-1 s-1, respectively.

Akaki, Yoji; Yamazumi, Noriyuki; Nakamura, Shigeyuki; Tokuda, Takahiro; Yoshino, Kenji

2012-10-01

22

Influence of post-deposition annealing in air and vacuum on the properties of thermally evaporated gallium oxide films  

NASA Astrophysics Data System (ADS)

Oxidative annealing in air or reductive annealing in vacuum around 773 K of thermally evaporated gallium oxide films produces monoclinic ?-Ga2O3 films of distinctly different compositional, optical, morphological and electrical properties. The pristine films prepared by the evaporation of Ga2O3 powders are oxygen deficient, amorphous and absorbing in UV-visible region. The air annealed films are transparent (band gap ?4.9 eV), display nanometric granular morphology and are characterized by <1.0 eV extrinsic and 1.2-1.6 eV intrinsic activation energies in the Arrhenius plots of electrical conductivity. The growth of Ga2O3 phase on vacuum annealing takes place through the decomposition of Ga2O, one of the constituents of the pristine films. The vacuum annealed films exhibit comparatively lower transparency (band gap <4.5 eV), comprise micron-sized dendrites or fibres and have <1.0 eV extrinsic and 1.7-2.0 eV intrinsic activation energies. The incorporation of these properties results from compositional changes in films induced by annealing in air or vacuum ambient.

Rao, Pritty; Kumar, Sanjiv

2014-06-01

23

Annealing single-walled metallic carbon nanotube devices in ultra-high vacuum  

NASA Astrophysics Data System (ADS)

Single walled carbon nanotube (SWNT) devices were fabricated and annealed in ultra high vacuum (UHV) with simultaneous electrical characterization. As one-dimensional crystals with nanometer scale diameters and up to meter scale lengths, SWNTs offer a unique opportunity to probe 1D transport in mesoscopic electronics. Furthermore, all of the atoms in SWNTs are surface atoms which means that the electronic properties can be examined and tailored using the well-developed tools of surface chemistry. However, electronic resistances and noise for technologically relevant small-diameter SWNT devices are too high for commercial applications. In this work, intrinsic and extrinsic sources of scattering in SWNTs were examined by heating SWNT field effect transistors in UHV with while monitoring changes in the devices' resistance, transconductance, and conductance fluctuations. The effects of the contact interface were studied by varying the electrode metal, including palladium, titanium, and platinum contacts. It was found that metal-SWNT contact interfaces are the primary scatterers in devices as fabricated, but the contact resistance can be greatly reduced by annealing to a limit that depends primarily on the surface chemistry of the electrode metal and the geometry of the interface. Secondary sources of scattering include surface adsorbates on the electrodes and substrate, sub-strate oxide phonons and SWNT phonons. Adsorbates are the primary source of 1/f conductance noise, followed by the electrode interface. Annealing devices in UHV was found to reduce the contact resistance, noise, and device to device inhomogeneity. Graphene, formed through catalysis on the Pt surface during the anneal, was found to make the best contact to SWNTs, rather than the conventional Pd, Ti, and Pt, both in terms of contact resistance and noise.

Kane, Alexander Allen

24

Vacuum annealing effects on the surface stoichiometry of InGaAsP  

SciTech Connect

The use of the binary and quaternary systems InP and In{sub 1{minus}x}Ga{sub x}As{sub 1{minus}y}P{sub y} for the fabrication of long wavelengths (i.e., 1.3-1.6{mu}m) LED's and lasers is a well-established approach. Our work is focused on the quaternay (Q) materials, with the major emphasis being on the surface chemistry of epitaxially grown Q-layers, lattice matched to InP and photoluminescing at about 1.3 {mu}m. In this paper the authors report on a surface stoichiometry shift that has been observed on annealing Q-layers up to about 600{degrees}C in a vacuum ({approximately}10{sup {minus}9} Torr).

Yeh, J.L.; Siu, S.Z. (Dept. of Electrical and Computer Engineering, Rutgers Univ., Piscataway, NJ (US)); Vasile, M.J.; Schwartz, B. (AT and T Bell Lab., Murray Hill, NJ (US))

1990-04-01

25

Impact of vacuum anneal at low temperature on Al2O3/In-based III-V interfaces  

NASA Astrophysics Data System (ADS)

We report on the effect of vacuum anneal on interfacial oxides formed between Al2O3 and III-V semiconductors. On InGaAs, no interfacial oxide is detected after annealing at 600 C under UHV whereas annealing under secondary vacuum favours the regrowth of thin InGaOx interfacial oxide. Lowering the temperature at 400 C highlights the effect of III-V substrates since In-OH bonds are only formed on InAs by OH release from TMA/H2O deposited alumina. On InGaAs, regrowth of InGaOx is observed, as a result of preferential oxidation of Ga. On InP, a transition from InPOx to POx is highlighted.

Martinez, E.; Grampeix, H.; Desplats, O.; Herrera-Gomez, A.; Ceballos-Sanchez, O.; Guerrero, J.; Yckache, K.; Martin, F.

2012-06-01

26

The effects of vacuum annealing on the structure and surface chemistry of iron:nickel alloy nanoparticles  

Microsoft Academic Search

In order to increase the longevity of contaminant retention on the particle surface, a method is sought to improve the corrosion\\u000a resistance of bimetallic iron nickel nanoparticles (INNP) used for the remediation of contaminated water, and thereby extend\\u000a their industrial lifetime. A multi-disciplinary approach was used to investigate changes induced by vacuum annealing (?8mbar) at 500C on the bulk and

Michelle Dickinson; Thomas B. Scott; Richard A. Crane; Olga Riba; Robert J. Barnes; Gareth M. Hughes

2010-01-01

27

Study of the I-V characteristics of nanostructured Pd films on a Si substrate after vacuum annealing  

SciTech Connect

The I-V characteristics of nanostructured Pd films on a Si substrate are investigated. The nanostructures (nanoislands) are formed by the vacuum annealing of continuous ultrathin Pd films sputtered onto a substrate. The shape of the I-V characteristics of the investigated Si substrate-Pd film system is shown to be heavily dependent on the degree of film nanostructuring. The surface morphology of the films is studied using scanning electron microscopy.

Tomilin, S. V., E-mail: tomilin_znu@mail.ru; Yanovsky, A. S.; Tomilina, O. A.; Mikaelyan, G. R. [Zaporozhye National University, Department of Semiconductor Physics (Ukraine)

2013-06-15

28

XANES and XPS studies of processes initiated by high-vacuum annealing in SnO x /MWCNT composite layers  

NASA Astrophysics Data System (ADS)

The initial and thermally treated composites based on SnO x /MWCNT have been studied by the XANES and XPS methods using the equipment of the BESSY II Russian-German beamline of synchrotron radiation and by the AES and HRTEM methods. The characteristic mechanisms of chemical and structural transformations in the SnO x phase have been determined depending on the vacuum annealing temperature. It has been found that the basic process in the metal-oxide component at annealing temperatures not exceeding 500C is the tin monoxide SnO disproportionation reaction with the formation of the dioxide SnO2 phase and metallic tin. An increase in the annealing temperature to 800C results in the activation of carbothermal reduction of metallic tin in contact areas of oxide clusters and MWCNT, as well as in the formation of nanocrystalline structures in the metal-oxide component of composite.

Bolotov, V. V.; Korusenko, P. M.; Nesov, S. N.; Povoroznyuk, S. N.; Shelyagin, R. V.

2013-06-01

29

Effects of vacuum annealing on the optical and electrical properties of p-type copper-oxide thin-film transistors  

NASA Astrophysics Data System (ADS)

We have investigated the effects of vacuum annealing on the optical and electrical properties of the p-type copper-oxide thin-film transistors (TFTs). The vacuum annealing of the copper-oxide thin-film was performed using the RF magnetron sputter at various temperatures. From the x-ray diffraction and UV-vis spectroscopy, it is demonstrated that the high-temperature vacuum annealing reduces the copper-oxide phase from CuO to Cu2O, and increases the optical transmittance in the visible part of the spectrum. The fabricated copper-oxide TFT does not exhibit the switching behavior under low-temperature vacuum annealing conditions. However, as the annealing temperature increases, the drain current begins to be modulated by a gate voltage, and the TFT exhibits a high current on-off ratio over 104 as the vacuum annealing temperature increases over 450 C. These results show that the vacuum annealing process can be an effective method of simultaneously improving the optical and electrical performances in p-type copper-oxide TFTs.

Sohn, Joonsung; Song, Sang-Hun; Nam, Dong-Woo; Cho, In-Tak; Cho, Eou-Sik; Lee, Jong-Ho; Kwon, Hyuck-In

2013-01-01

30

Enhanced reactivity of nanoscale iron particles through a vacuum annealing process  

Microsoft Academic Search

A reactivity study was undertaken to compare and assess the rate of dechlorination of chlorinated aliphatic hydrocarbons (CAHs)\\u000a by annealed and non-annealed nanoscale iron particles. The current study aims to resolve the uncertainties in recently published\\u000a work studying the effect of the annealing process on the reduction capability of nanoscale Fe particles. Comparison of the\\u000a normalized rate constants (m2\\/h\\/L) obtained

Olga RibaRobert; Robert J. Barnes; Thomas B. Scott; Murray N. Gardner; Simon A. Jackman; Ian P. Thompson

31

Influence of annealing in vacuum and in air on magnetic, crystallographic and morphological properties of thin YIG films  

NASA Astrophysics Data System (ADS)

The Yttrium Iron Garnet (YIG) is chosen by our laboratory for the integration of passive components in the microwaves domain and for the miniaturization of integrated inductors and transformers. Magnetic and morphological characterizations are essential for the development of these components. To fabricate a micro-inductor of solenoid type, we have deposited on an alumina substrate, by RF sputtering, a thin YIG film between two layers of copper. We have also used the photolithography technique in a clean room to obtain the desired pattern of the coil. The YIG films are amorphous after deposition, the annealing at 740C for 2 hours is necessary for them to be crystallized and to have magnetic properties. To avoid the deterioration of copper layers, the Classical Thermal Annealing (CTA) was replaced by a Vacuum Thermal Annealing (VTA). Before manufacturing the integrated inductor, it is interesting to do the magnetic, crystallographic and morphological characterizations of YIG films after annealing with both techniques of thermal treatment. To check the quality of the prototype, we have done different characterizations: VSM, Kerr effect, XRD, SEM. The results obtained with VTA were better than of CTA comparing them with bulk YIG properties.

Siblini, A.; Khalil, I.; Chatelon, J. P.; Blanc-Mignon, M. F.; Jamon, D.; Rousseau, J. J.

2013-01-01

32

Electrical activation phenomena induced by excimer laser annealing in B-implanted silicon  

SciTech Connect

The activation process induced by excimer laser annealing (ELA) has been investigated in 10 keV B-implanted samples. It is found that for energy densities inducing melt depths of the order or larger of the implanted region the junction depth is controlled by the melt depth, with activation approaching 100% and box-shaped carrier density distributions with abrupt junction profile. For energy densities inducing a melting shallower than the implanted region, two different activation mechanisms have been identified: the first occurring in the molten region and leading to complete B activation; the second occurring in the region immediately below the molten zone and leading to thermal activation of B, induced by the heat wave propagating into the Si wafer. This last process is characterized by an activation energy of 5 eV and is not accompanied by B diffusion. As a consequence, a deep tail of active B is produced, preventing the possibility to form abrupt and ultrashallow junctions. These results suggest that for the formation of ultrashallow junctions it is essential to combine ELA with ultralow energy ion implantation.

Fortunato, G.; Mariucci, L.; La Magna, A.; Alippi, P.; Italia, M.; Privitera, V.; Svensson, B.; Monakhov, E. [IFN-CNR, Via Cineto Romano 42, 00156 Rome (Italy); IMM-CNR, Stradale Primosole 50, 95121 Catania (Italy); University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

2004-09-20

33

Hydrogen release from diamondlike carbon films due to thermal annealing in vacuum  

Microsoft Academic Search

Depth profiles of absolute hydrogen concentration in diamondlike carbon (DLC) films deposited on glass substrate by a dual-ion beam sputtering system and in thermally annealed DLC films (pressure: 6.65 10?3 Pa) at 300, 400, 500 and 600C were measured by the Elastic Recoil Detection Analysis (ERDA) using a 2.4 MeV 4He2+ ion beam. The thermal annealing induced C?H bond

W. J. Wang; T. M. Wang; B. L. Chen

1996-01-01

34

Hydrogen release from diamondlike carbon films due to thermal annealing in vacuum  

Microsoft Academic Search

Depth profiles of absolute hydrogen concentration in diamondlike carbon (DLC) films deposited on glass substrate by a dual-ion beam sputtering system and in thermally annealed DLC films (pressure: 6.65 10-3 Pa) at 300, 400, 500 and 600C were measured by the Elastic Recoil Detection Analysis (ERDA) using a 2.4 MeV He4e2+ ion beam. The thermal annealing induced C-H bond

T. M. Wang; W. J. Wang; B. L. Chen

1996-01-01

35

The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics  

NASA Technical Reports Server (NTRS)

In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

Wright, K. H., Jr.; Stone, N. H.; Samir, U.

1983-01-01

36

Hydrogen release from diamondlike carbon films due to thermal annealing in vacuum  

NASA Astrophysics Data System (ADS)

Depth profiles of absolute hydrogen concentration in diamondlike carbon (DLC) films deposited on glass substrate by a dual-ion beam sputtering system and in thermally annealed DLC films (pressure: 6.65 10 -3 Pa) at 300, 400, 500 and 600C were measured by the Elastic Recoil Detection Analysis (ERDA) using a 2.4 MeV 4He 2+ ion beam. The thermal annealing induced C?H bond changes in films were investigated by the infrared transmittance spectra of film layers. It showed that the thermal annealing led to the release of hydrogen from the films and the breaking of C?H bonds in the films. The threshold temperature for hydrogen release was about 400C, but the breaking of C?H bonds occurred mainly at temperature higher than 400C. At 500 and 600C, most C?H bonds were broken while the annealed films still contained a certain amount of hydrogen atoms which were not in the form of C?H bonds. It also showed that hydrogen release occurred at both the film's surface and the film/substrate interfaces. At temperature higher than 400C, the release speed of hydrogen through the interfaces was much higher than that through the film's surface. This then led to un-uniform distribution of retained hydrogen atoms in the films. The present results were compared with the observations reported before and good agreement was obtained.

Wang, W. J.; Wang, T. M.; Chen, B. L.

1996-08-01

37

Blue luminescent centers and microstructural evaluation by XPS and Raman in ZnO thin films annealed in vacuum, N 2 and O 2  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films prepared on sapphire substrates by employing a pulsed laser deposition (PLD) have been annealed in vacuum, N 2, and O 2 ambient at annealing temperature 600 C. X-ray diffraction (XRD) and atomic force microscopy (AFM) observation show that the annealed thin films possess (0 0 0 2) textured feature and form better crystal grains with a large size. X-ray photoelectron spectroscopy (XPS) and Raman analysis show the defects of ZnO thin films annealed in different ambient is distinctly different. The film annealed in vacuum possesses large oxygen vacancies (V o) and Zn interstitials (Zn i); while large surface defects exist in film annealed in N 2 ambient. The concentrations of the intrinsic and extrinsic defects are the lowest in ZnO thin film annealed in oxygen gas. Photoluminescence (PL) spectra also reveal that the ultraviolet (UV) emission is the best for thin film annealed in O 2. The blue emission (2.66 eV) is ascribed to the electronic transition from the donor energy level of Zn interstitials to acceptor energy level of Zn vacancies rather than the O vacancy.

Wei, X. Q.; Man, B. Y.; Liu, M.; Xue, C. S.; Zhuang, H. Z.; Yang, C.

2007-01-01

38

Effect of High-Temperature Annealing in Vacuum and Hydrogen on Paramagnetic Defects in Diamond Films Grown by Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Diamond films of high quality were prepared by hot-filament chemical vapor deposition, and were annealed at a temperature of between 1300-1400C in vacuum and hydrogen atmosphere. The electron spin resonance (ESR) spectrum did not change in shape and intensity for the films annealed in vacuum, but it changed in shape for the films annealed in hydrogen. This change could not be explained if the ESR signal was attributed to a single center such as an H1 center. From computer simulation for the ESR spectrum, we found that two more centers are necessary besides the H1 center. The change in shape produced by annealing in hydrogen resulted from a change in the relative amounts of the three centers.

Watanabe, Ichiro; Yata, Masaru; Kanatani, Minoru; Kawaguchi, Yuhsuke

2002-02-01

39

Photon stimulated desorption phenomena at the Taiwan Light Source vacuum system  

NASA Astrophysics Data System (ADS)

The photon stimulated desorption (PSD) by the synchrotron radiation irradiated from the Taiwan Light Source (TLS) vacuum chambers were analyzed. The desorption behavior of the various gas species were compared by either adjusting the electron beam orbit and hitting the photons on the fresh chamber walls or turning off the pumps. The dominated gases during the earlier years' operation are the H2, in concentration of > 90followed by other gases, e.g. CO, H2O, CH4, etc.. However, some of the massive gas species, e.g. CxHy, CxFy, were observed after replacing the new vacuum parts or unsuitable baking the O-ring gate valves in higher temperature. The contaminated gases are to be reduced by beam-self cleaning treatment. Planning in upgrading the storage ring vacuum system is also described.

Hsiung, G. Y.; Hsu, Y. J.; Chen, J. R.

1997-05-01

40

Buried-interfacial reactivity of palladium-coated Fe2O3\\/FeTi thin films during vacuum or hydrogen annealing  

Microsoft Academic Search

FeTi is considered a good material for solid state hydrogen storage; however, it must undergo an initial activation by either a vacuum or hydrogen annealing procedure after preparation or exposure to air. Previous studies indicate that the initial activation in vacuum causes a reduction of surface iron oxides by a solid state reaction with FeTi to produce TiO2. Palladium has

J. H. Sanders; B. J. Tatarchuk

1990-01-01

41

Effect of thermal annealing in vacuum and in air on nanograin sizes in hard and superhard coatings Zr-Ti-Si-N.  

PubMed

Zr-Ti-Si-N coating had high thermal stability of phase composition and remained structure state under thermal annealing temperatures reached 1180 degrees C in vacuum and 830 degrees C in air. Effect of isochronous annealing on phase composition, structure, and stress state of Zr-Ti-Si-N-ion-plasma deposited coatings (nanocomposite coatings) was reported. Below 1000 degrees C annealing temperature in vacuum, changing of phase composition is determined by appearing of siliconitride crystallites (beta-Si3N4) with hexagonal crystalline lattice and by formation of ZrO2 oxide crystallites. Formation of the latter did not result in decay of solid solution (Zr, Ti)N but increased in it a specific content of Ti-component. Vacuum annealing increased sizes of solid solution nanocrystallites from (12 to 15) in as-deposited coatings to 25 nm after annealing temperature reached 1180 degrees C. One could also find macro- and microrelaxations, which were accompanied by formation of deformation defects, which values reached 15.5 vol.%. Under 530 degrees C annealing in vacuum or in air, nanocomposite coating hardness increased. When Ti and Si concentration increased and three phases nc-ZrN, (Zr, Ti)N-nc, and alpha-Si3N4 were formed, average hardness increased to 40.8 +/- 4 GPa. Annealing to 500 degrees C increased hardness and demonstrated lower spread in values H = 48 +/- 6 GPa and E = (456 +/- 78) GPa. Zr-Ti-Si-N coatings has high wear resistance and low friction coefficient in comparison at a temperature of 500 degrees C possess with coatings TiN, Ti-Si-N. PMID:23447980

Pogrebnjak, A D; Shpak, A P; Beresnev, V M; Kolesnikov, D A; Kunitskii, Yu A; Sobol, O V; Uglov, V V; Komarov, F F; Shypylenko, A P; Makhmudov, N A; Demyanenko, A A; Baidak, V S; Grudnitskii, V V

2012-12-01

42

Rapid thermal annealing effects on vacuum evaporated ITO for InGaN/GaN blue LEDs  

NASA Astrophysics Data System (ADS)

8 mil 10 mil InGaN/GaN blue LEDs with indium tin oxide (ITO) emitting at 460 nm were fabricated. A vacuum evaporation technique was adopted to deposit ITO on P-GaN with thickness of 240 nm. The electrical and optical properties of ITO films on P-GaN wafers, as well as rapid thermal annealing (RTA) effects at different temperatures (100 to 550 C) were analyzed and compared. It was found that resistivity of 450 C RTA was as low as 1.19 10-4 ?cm, along with a high transparency of 94.17% at 460 nm. AES analysis indicated the variation of oxygen content after 450 C annealing, and ITO contact resistance showed a minimized value of 3.9 10-3 ?cm2. With 20 mA current injection, it was found that forward voltage and output power were 3.14 V and 12.57 mW. Furthermore, maximum luminous flux of 0.49 lm of ITO RTA at 550 C was measured, which is the consequence of a higher transparency.

Yan, Ding; Weiling, Guo; Yanxu, Zhu; Jianpeng, Liu; Weiwei, Yan

2012-06-01

43

Effect of Vacuum Annealing on the Characteristics of Plasma Sprayed Al2O3-13wt.%TiO2 Coatings  

NASA Astrophysics Data System (ADS)

Adhesion strength is one of the critical properties for plasma-sprayed coating. In this study, the plasma-sprayed Al2O3-13wt.%TiO2/NiCrAl coatings were annealed at 300-900 C for 6 h in vacuum. The tensile bond strength and porosity of the coatings were investigated. The microstructure and the fracture were studied using optical microscopy, scanning electron spectroscopy, and x-ray diffraction. It was found that the tensile bond strength of coatings increased with the increase of annealing temperature until 500 C, reaching the maximum value of 41.2 MPa, and then decreased as the annealing temperature continues to increase. All coatings presented a brittle fracture and the fracture occurred inside the ceramic coatings except for the coating annealed at 500 C, which had a brittle-ductile mixed fracture and the fracture occurred at the interface of bond coating and the substrate.

Jingjing, Zhang; Zehua, Wang; Pinghua, Lin; Hongbin, Yuan; Zehua, Zhou; Shaoqun, Jiang

2012-09-01

44

Epitactic formation of forsterite on MgO single crystals during vacuum annealing  

SciTech Connect

Specimens of {l_brace}0 0 1{r_brace} MgO, prepared for analysis in the transmission electron microscope (TEM), have been heated in situ in a conventional TEM in order to study the effect of different heat treatments on the surface of the MgO specimens. A previous study, using a similar in situ heat treatment of MgO, found that at elevated temperatures ({approx}500 K) a film of different structure and composition formed on the surface of the sample. The previous study concluded that the composition and structure corresponded to that of MgO{sub 2}. In the present study, similar results to those shown previously have been found. However, the interpretation of these results is quite different. The films are shown to be of a composition and crystal structure that is consistent with forsterite, Mg{sub 2}SiO{sub 4}. The films can form as a result of contamination during the high-temperature in situ annealing process.

Farrer, J.K. [Brigham Young University; Johnson, M.T. [Seagate Technology, Bloomington, MN; Bentley, James [ORNL; Carter, C.B. [University of Minnesota

2005-01-01

45

Amorphous Magnesiosilicate Smokes Annealed in Vacuum: The Evolution of Magnesium Silicates in Circumstellar and Cometary Dust  

NASA Astrophysics Data System (ADS)

The mid-infrared spectral evolution of amorphous metastable eutectic magnesiosilica smokes, obtained by kinetically controlled gas-to-solid condensation of a Mg-SiO-O 2-H 2 vapor, proceeded in three distinct phases as a function of increasing time and temperature. This paper reports the mineralogical and chemical properties of these same samples. We found a previously unanticipated size dependence of the petrologic development of the initially amorphous magnesiosilica smokes that may also be at least partially responsible for the previously reported spectroscopic changes. Condensed grains less than approximately 20 nm in diameter remained amorphous throughout the thermal annealing experiment. Mineralogical changes occurred only after fusion of condensed magnesiosilica grains and chemical homogenization of large amorphous agglomerates and ring structures. Kinetically favored nucleation and growth produced the thermodynamically unstable nanocrystalline assemblage forsterite + tridymite. Further mineralogical development was stalled until continued fusing of agglomerates, rings, and some fraction of condensed grains had produced smooth amorphous magnesiosilica sheets of 42 and 20 wt% MgO. In rare sheets with more than 55 wt% MgO large forsterite crystals had grown, while enstatite had nucleated in low-MgO sheets still in the presence of forsterite and tridymite. The mineralogical evolution of the samples is critically dependent on the mass of the structural entities in the condensed sample and seems to be restricted to fused agglomerates and ring structures larger than about 20 nm in diameter and the sheet materials. We discuss the implications of our study for the interpretation of similar astrophysical dust analog studies and for astrophysical applications.

Rietmeijer, Frans J. M.; Hallenbeck, Susan L.; Nuth, Joseph A.; Karner, Jim M.

2002-03-01

46

High-Vacuum Annealing of Polythiophene:Methanofullerene Bulk Heterojunction Solar Cells  

NASA Astrophysics Data System (ADS)

Solar cell device architectures incorporating photoactive layers of immiscible blends of organic semiconductors achieve improved photovoltaic power conversion efficiency compared to planar device geometries. We have fabricated bulk heterojunction solar cells with active layer blends of poly-3 hexylthiophene (P3HT) and the fullerene derivative, [6,6] phenyl C61-butyric acid methyl ester (PCBM). Spin casting the blend from a chlorobenzene solution forms nanometer-scale domains of electron donor and acceptor phases in the device active layer. We solution process the active layers in ambient atmospheric conditions prior to aluminum contact evaporation resulting in inevitable oxygen adsorption in the P3HT bulk and interfaces. We have investigated several device post-fabrication thermal treatments for driving oxygen from the device active layer, including different temperatures, times, and vacuum pressures. We evaluate the efficacy of this technique in improving Al contact quality, film morphology, solar cell efficiency, and reproducibility via analysis of device current-voltage characteristics and tapping mode atomic force microscopy.

Segui, Jennifer; Gearba, Ioana; Rafailovich, Miriam; Black, Charles

2009-03-01

47

The Effect of Surface Cleaning by Wet Treatments and Ultra High Vacuum Annealing for Ohmic Contact Formation of P-Type GaN  

NASA Astrophysics Data System (ADS)

The effect of surface cleaning techniques on the properties of the metal/p-GaN contacts has been studied using X-ray photoelectron spectroscopy (XPS) and I-V measurements. It has been clarified that the contact resistance strongly depends on the amount of the surface residues such as oxygen and carbon just before the electrode deposition. We have also found that the annealing in ultra high vacuum (UHV) is effective to reduce the residues. It has turned out that the combination of the hydrochloric acid and sulfuric acid hydrogen peroxide mixtures cleaning followed by the UHV annealing is promising for the improvement in the contact characteristics.

Waki, Ichitaro; Fujioka, Hiroshi; Ono, Kanta; Oshima, Masaharu; Miki, Hisayuki; Fukizawa, Akira

2000-07-01

48

Electron-induced decomposition of methanol on the vacuum-annealed surface of TiO 2(110)  

NASA Astrophysics Data System (ADS)

The 100 eV electron-induced decomposition (EID) of methanol adsorbed on the vacuum-annealed surface of TiO 2(110) at 135 K was examined with temperature-programmed desorption (TPD) and electron-stimulated desorption (ESD). By annealing at 850 K, a TiO 2(110) surface was reproducibly prepared with an oxygen vacancy coverage of about 0.08 ML (where 1 ML=5.210 14 sites cm -2). In the absence of electron irradiation, CH 3OH adsorbed on the vacuum-annealed surface in three main TPD states: a molecular state at 295 K and two dissociative states at 350 and 480 K. The 480 K state was assigned to methoxyls at oxygen vacancy sites, and the 350 K state was due to methoxyls at non-vacancy sites. The surface coverages in these states for the saturated monolayer were 0.40 ML (295 K), 0.15 ML (350 K) and 0.08 ML (480 K). Although CH 3OH dissociated on the surface, no irreversible decomposition was observed, and CH 3OH was the only desorption product in TPD. By heating a multilayer CH 3OH exposure to 197, 310 and 410 K, followed by recooling to 135 K, methanol adlayers could be prepared containing only the saturated monolayer, only both types of methoxyl and only the methoxyls at vacancies, respectively. Given these preparation conditions, the 100 eV EID of each methanol-related species was examined. Using CD 3OD, the major positive ESD ions detected from multilayer methanol were D +, O +/CD 2+ and OD +/CD 3+ (the latter were mostly O + and OD + based on results with CH 3OH) with weaker signals from C +, CD +, CO +, DCO + and CD 2OD +. However, the monolayer gave D + and O +, with weak signals from OD + and CD +. The EID cross-section for molecularly adsorbed CH 3OH (1.710 -16 cm 2) was only a factor of three less than the literature values for the total dissociative cross-section in the gas phase suggesting that the TiO 2(110) surace had little or no influence on the dissociative ionization process. No carbon-containing surface products were detected in post-irradiation TPD associated with EID of molecular CH 3OH, including no additional methoxyl formation. The initial EID cross-sections for the two types of methoxyls were approximately equivalent regardless of the surface condition, but were a factor of 5 greater in the presence of CH 3OH (3.0-3.410 -15 cm 2) than in its absence (5.8-6.210 -16 cm 2). EID of both vacancy and non-vacancy methoxyl resulted in H 2CO products bound at the same sites, but vacancy-bound H 2CO was resistant to further EID, whereas non-vacancy H 2CO was decomposed with further electron exposure. Total D + ESD cross-sections were several orders of magnitude lower than those measured by post-irradiation TPD, suggesting that the major EID channels involved ejection of neutral species. These results demonstrated the ability of low-energy electrons to active organics adsorbed on oxide surfaces with high cross-sections, and suggest that the EID cross-sections and products for surface organics depend on the coverage, adsorption state and adsorption site as in the case of methanol in TiO 2(110). Based on these conclusions, low-energy electrons produced from adsorption of ionizing radiation may play a significant role in the radiocatalytic destruction of organics over oxide catalysts.

Henderson, M. A.; Otero-Tapia, S.; Castro, M. E.

1998-09-01

49

Characteristics of Al-doped ZnO thin films prepared in Ar + H{sub 2} atmosphere and their vacuum annealing behavior  

SciTech Connect

The microstructure and electricaloptical properties of Al-doped ZnO (AZO) films have been studied as a function of H{sub 2} flux in the magnetron sputtering process at 150 C and postannealing temperature in vacuum. As H{sub 2} flux increases in the sputtering gas, the AZO films deposited have a (002) preferred orientation rather than the mixed (100) and (002) orientations, the grain size shows a tendency to first increase then decrease, and (002) diffraction peak position is inclined to shift to higher angles first then to lower angles. The resistivity of the films first decreases then increases with H{sub 2} flux, and the lowest resistivity of 4.02 10{sup ?4}? cm is obtained at a H{sub 2} flux of 10 sccm. The average transmittance in the visible region shows little dependence on H{sub 2} flux. As a whole, the AZO films with higher values of figure of merit are obtained when the H{sub 2} flux is in the range of 612 sccm. The AZO films deposited in Ar and Ar + H{sub 2} exhibit different annealing behaviors. For the AZO film deposited in Ar, the grain size gradually increases, the stresses are relaxed, the resistivity first decreases then increases, and the average transmittance in the visible region is unchanged initially then somewhat decreased as annealing temperature is increased. The optimum annealing temperature for improving properties of AZO films deposited in Ar is 300 C. For the AZO films deposited in Ar + H{sub 2}, annealing does not significantly change the microstructure but increases the resistivity of the films; the average transmittance in the visible region remains unchanged initially but greatly reduced with further increase in annealing temperature. The carrier transport in the as-deposited and annealed films appears to be controlled by a mechanism of grain boundary scattering, and the value of E{sub g} increases with the increase in carrier concentration due to BursteinMoss effect.

Zhu, Bailin; L, Kun; Wang, Jun; Li, Taotao; Wu, Jun [Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China)] [Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Zeng, Dawen; Xie, Changsheng [Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)] [Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2013-11-15

50

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Vacuum relaxation and annealing-induced enhancement of mobility of regioregular poly (3-hexylthiophene) field-effect transistors  

NASA Astrophysics Data System (ADS)

In order to enhance the performance of regioregular poly(3-hexylthiophene) (RR-P3HT) field-effect transistors (FETs), RR-P3HT FETs are prepared by the spin-coating method followed by vacuum placement and annealing. This paper reports that the crystal structure, the molecule interconnection, the surface morphology, and the charge carrier mobility of RR-P3HT films are affected by vacuum relaxation and annealing. The results reveal that the field-effect mobility of RR-P3HT FETs can reach 4.17 10-2 m2/(V s) by vacuum relaxation at room temperature due to an enhanced local self-organization. Furthermore, it reports that an appropriate annealing temperature can facilitate the crystal structure, the orientation and the interconnection of polymer molecules. These results show that the field-effect mobility of device annealed at 150 C for 10 minutes in vacuum at atmosphere and followed by placement for 20 hours in vacuum at room temperature is enhanced dramatically to 9.00 10-2 cm2/(V s).

Tian, Xue-Yan; Xu, Zheng; Zhao, Su-Ling; Zhang, Fu-Jun; Xu, Xu-Rong; Yuan, Guang-Cai; Li, Jing; Sun, Qin-Jun; Wang, Ying

2009-11-01

51

Annealing-temperature effects on the properties of ZnO thin films and Pd/ZnO Schottky contacts grown on n-Si (1 0 0) substrates by vacuum deposition method  

NASA Astrophysics Data System (ADS)

The effects of annealing temperature on the properties of ZnO thin films and Pd/ZnO thin film Schottky contacts grown on the n-silicon (n-Si) substrates by vacuum evaporation technique have been reported for the first time in this paper. The as-grown ZnO thin films were annealed in the Argon gas atmosphere for a same duration of 20 min at 450 C, 550 C and 650 C temperatures. The surface morphology of the films analyzed by the scanning electron microscopy and X-ray diffraction spectroscopy are observed to be modified with annealing temperature. The photoluminescence and resistivity measurements were carried out to report the effects of annealing temperature on the optical and electrical properties of the vacuum deposited ZnO thin films. The Pd Schottky contacts grown on the annealed ZnO thin films at 550 C annealing temperature is observed to have the superior electrical characteristics over the Schottky contacts on ZnO films annealed at 450 C and 650 C temperatures.

Yadav, Aniruddh Bahadur; Singh, Kunal; Pandey, Amritanshu; Jit, S.

2014-07-01

52

Compositional study of vacuum annealed Al doped ZnO thin films obtained by RF magnetron sputtering  

SciTech Connect

Aluminum doped zinc oxide (AZO) thin films were obtained by RF magnetron sputtering. The effects of deposition parameters such as power, gas flow conditions, and substrate heating have been studied. Deposited and annealed films were characterized for composition as well as microstructure using x ray photoelectron spectroscopy and x ray diffraction. Films produced were polycrystalline in nature. Surface imaging and roughness studies were carried out using SEM and AFM, respectively. Columnar grain growth was predominantly observed. Optical and electrical properties were evaluated for transparent conducting oxide applications. Processing conditions were optimized to obtain highly transparent AZO films with a low resistivity value of 6.67 x 10{sup -4}{Omega} cm.

Shantheyanda, B. P.; Todi, V. O.; Sundaram, K. B.; Vijayakumar, A.; Oladeji, I. [Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States); Planar Energy Inc., 653 W. Michigan St., Orlando, Florida 32805 (United States)

2011-09-15

53

Temperature-dependent phase separation during annealing of Ge2Sb2Te5 thin films in vacuum  

NASA Astrophysics Data System (ADS)

Thermal stability of 100 nm Ge2Sb2Te5 thin film during annealing from room temperature to 240 C inside a UHV chamber was studied in situ by X-ray photoelectron spectroscopy (XPS) and ex situ by X-ray diffraction (XRD) and atomic force microscopy (AFM). Ge species are found to diffuse preferentially to the surface when GST film is annealed from 25 C to 100 C. This process is accompanied by a change of phase whereby the amorphous film completely becomes face-center-cubic (FCC) phase at 100 C. From 100 C to 200 C, both Sb and Te species are observed to diffuse more to the surface. The FCC phase is partially changed into hexagonal-close-pack (HCP) phase at 200 C. At 220 C, FCC phase is completely transformed into HCP phase. Loss of Sb and Te are also detected from the surface and this is attributed to desorption due to their high vapor pressures. At 240 C, Sb and Te species are found to have desorbed completely from the surface, and leave behind Ge-rich 3D droplets on the surface. The separation of Ge2Sb2Te5 into Sb,Te-rich phase and Ge-rich phase is thus the main mechanism to account for the failure of Ge2Sb2Te5-based phase change memory devices under thermal stress.

Zhang, Zheng; Pan, Jisheng; Fang, Lina Wei-Wei; Yeo, Yee-Chia; Foo, Yong Lim; Zhao, Rong; Shi, Luping; Tok, Eng Soon

2012-06-01

54

Templating rare-earth hybridization via ultrahigh vacuum annealing of ErCl3 nanowires inside carbon nanotubes  

NASA Astrophysics Data System (ADS)

Here we report on controlling the effective hybridization and charge transfer of rare-earth elements inside a carbon nanotube (CNT) nanoreactor. The tubular space inside CNTs can encapsulate one-dimensional (1D) crystals such as ErCl3, which we have used as a starting material. Applying a thermochemical reaction in ultrahigh vacuum, we obtain elemental Er nanowires still encapsulated in the CNTs. The hybridization degree and the effective charge changes were directly accessed across the Er 4d and 3d edges by high-energy spectroscopy. It was found that Er is trivalent but the effective valence is reduced for the Er-filled tube, which strongly suggests an increased hybridization between the nanotube ? states and the Er 5d orbitals. This was also evidenced by the conduction band response determined in C1s-x-ray absorption spectroscopy (XAS). These results have significant implications for the 1D electronic and magnetic properties of these and similar rare-earth nanowire hybrids.

Ayala, Paola; Kitaura, Ryo; Nakanishi, Ryo; Shiozawa, Hidetsugu; Ogawa, Daisuke; Hoffmann, Patrick; Shinohara, Hinsanori; Pichler, Thomas

2011-02-01

55

Structural, optical, and ferromagnetic properties of Co-doped TiO2 films annealed in vacuum  

NASA Astrophysics Data System (ADS)

Polycrystalline anatase Ti1-xCoxO2 (x=0-0.06) films have been fabricated by sol-gel spin coating. The effects of Co doping on the structural, optical, and magnetic properties are investigated. It is shown that oxygen vacancies and/or defects in the films are generated during thermal treatment in vacuum. Co doping reduces crystal quality and inhibits crystalline grain growth. Due to the introduction of Co, photoluminescence (PL) spectra become weak and the band gap emission has a blueshift. PL spectra reveal that the solubility of Co is lower than 0.02. At 300 K, the saturated magnetization is around 1.8 ?B/Co, which is independent of the concentration of Co. This value is approximately equivalent to the average magnetic moment of bulk metallic cobalt (1.75 ?B/Co). Zero-field-cooling/field-cooling measurements indicate that room temperature ferromagnetism in Co-doped TiO2 films is not an intrinsic property of the material. The presence of Co metal is identified by x-ray photoelectron spectroscopy and scanning electron microscopy.

Xu, Jianping; Shi, Shaobo; Li, Lan; Zhang, Xiaosong; Wang, Yaxin; Chen, Ximing; Wang, Jianfeng; Lv, Liya; Zhang, Fengming; Zhong, Wei

2010-03-01

56

In-situ x-ray diffraction studies on post-deposition vacuum-annealing of ultra-thin iron oxide films  

SciTech Connect

A maghemite ({gamma}-Fe{sub 2}O{sub 3}) film of 8.3 nm thickness is epitaxially grown on MgO(001) single crystal substrate by reactive molecular beam epitaxy. Chemical composition and crystal structure of the surface was studied by x-ray photoelectron spectroscopy and low energy electron diffraction, respectively. Afterwards the sample was moved to a heating cell for in situ x-ray diffraction experiments on the post-deposition annealing process in high-vacuum to study structural phase transitions of the iron oxide film. The iron oxide film is reduced with increasing temperature. This reduction occurs in two steps that are accompanied by structural transitions. The first step is a reduction from {gamma}-Fe{sub 2}O{sub 3} to Fe{sub 3}O{sub 4} at 360 deg. C and the second step is the reduction from Fe{sub 3}O{sub 4} to FeO at 410 deg. C.

Bertram, F.; Deiter, C.; Pflaum, K. [Hamburger Synchrotronstrahlungslabor am Deutschen Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg (Germany); Suendorf, M.; Otte, C.; Wollschlaeger, J. [Physics Department, University Osnabrueck, Barbarastr. 7, 49069 Osnabrueck (Germany)

2011-11-15

57

Effect of Annealing Temperature on Tribological Properties and Material Transfer Phenomena of CrN and CrAlN Coatings  

NASA Astrophysics Data System (ADS)

This study evaluates the effects of annealing temperature and of the oxides produced during annealing processes on the tribological properties and material transfer behavior between the PVD CrN and CrAlN coatings and various counterface materials, i.e., ceramic alumina, steel, and aluminum. CrAlN coating has better thermal stability than CrN coating in terms of hardness degradation and oxidation resistance. When sliding against ceramic Al2O3 counterface, both CrN and CrAlN coatings present excellent wear resistance, even after annealing at 800 C. The Cr-O compounds on the coating surface could serve as a lubricious layer and decrease the coefficient of friction of annealed coatings. When sliding against steel balls, severe material transfer and adhesive wear occurred on the CrN and CrAlN coatings annealed at 500 and 700 C. However, for the CrAlN coating annealed at 800 C, much less material sticking and only small amount of adhesive wear occurred, which is possibly due to the formation of a continuous Al-O layer on the coating outer layer. The sliding tests against aluminum balls indicate that both coatings are not suitable as the tool coatings for dry machining of aluminum alloys.

Wang, Linlin; Nie, X.

2013-10-01

58

Accelerated formation of metal oxide thin film at 200 C using oxygen supplied by a nitric acid additive and residual organic suction vacuum annealing for thin-film transistor applications.  

PubMed

Oxide semiconductors have gradually replaced amorphous and polycrystalline silicon for thin-film transistor (TFT) because of their high mobility and large-area uniformity. Especially, the oxide semiconductors have also achieved the low-cost manufacturing using a solution process. However, because the solution-processed oxide semiconductors require a high thermal energy to form the oxide thin film, the additional solution synthesis and annealing process are needed for low-temperature solution process. Because the conventional solution-processed oxide thin films have low oxidation level and high residual organic concentration at low annealing temperature, we propose the novel solution process that includes the nitric acid additive and the vacuum ambient annealing as an oxidizing agent and a residual organic suction, respectively. Therefore, we have successfully developed the simple oxide solution process and the soluble InZnO TFT with high field-effect mobility of 3.38 cm(2)/(V s) at 200 C. PMID:23962037

Jeong, Woong Hee; Kim, Dong Lim; Kim, Hyun Jae

2013-09-25

59

Heating steels in vacuum  

SciTech Connect

It is recommended that high-strength and corrosion-resistant steels be heated in an electric vacuum furnace. Absence of oxidation and decarburization, decrease in the deformation of the part, increase in service life, plus safety, and nontoxicity in the shop, are cited as advantages. Annealing, carburizing, hardening, brazing, and sintering--all detailed-can be more efficiently accomplished in vacuum heating. As vacuum heating requires certain surface conditions, the compositions of residual mediums is studied. The microrelief and surface finish obtained after vacuum heating is determined. Annealing in a vacuum is compared to annealing in air, a depletion in manganese indicating a greater savings by use of vacuum. Ductility is also tested. The gas of special purity nitrogen is recommended for best results. In general, then, use of electric vacuum furnaces is recommended.

Marmer, E.N.

1983-03-01

60

Vacuum electron field emission from SnO{sub 2} nanowhiskers annealed in N{sub 2} and O{sub 2} atmospheres  

SciTech Connect

The field emission properties of SnO{sub 2} nanowhiskers were observed to change after annealing under O{sub 2} and N{sub 2}. The electron current increased significantly from the sample annealed in N{sub 2} and the threshold field decreased from 3.17 V/{mu}m of the as-grown sample to 2.59 V/{mu}m of the annealed sample. The mechanism of the field emission enhancement was explored using Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy (XPS). The results reveal that after annealing in N{sub 2}, the amount of Sn-O bonds decreased and N atoms were introduced onto the surface. The binding energies of Sn 3d and O 1s determined by high resolution XPS analysis show a shift of 0.55 and 0.47 eV, respectively, toward the high energy side. This shows that the electron emission enhancement arises from a decrease in the work function. The changes in the field emission effect from the sample annealed in O{sub 2} are different and a possible mechanism is also proposed.

Luo Suhua; Chu, Paul K.; Di Zengfeng; Zhang Miao; Liu Weili; Lin Chenglu; Fan Jiyang; Wu Xinglong [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Research Center of Semiconductor Functional Film Engineering, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China) and National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

2006-01-02

61

Applications of infrared spectroscopy in the study of catalytic reactions and related adsorption phenomena on single crystal electrodes: connections between electrochemical and ultra high vacuum surface science  

Microsoft Academic Search

The aim of this review is to describe applications of infrared spectroscopy in the study of catalytic reactions and related adsorption phenomena at single crystal electrodes. The majority of work in this area has focused on reactions that form adsorbed CO as an intermediate, such as the electrochemical oxidation pathways of CO and several small organic molecules. In particular, studies

Carol Korzeniewski; Mark W. Severson

1995-01-01

62

Microwave annealing  

NASA Astrophysics Data System (ADS)

Microwave annealing of dopants in Si has been reported to produce highly activated junctions at temperatures far below those needed for comparable results using conventional thermal processes. However the details of the kinetics and mechanisms for microwave annealing are far from well understood. Comparisons between MWA and RTA of dopants in implanted Si has been investigated to produce highly activated junctions. First, As, 31P, and BF2 implants in Si substrate were annealed by MWA at temperatures below 550 C.

Lee, Yao-Jen; Cho, T.-C.; Chuang, S.-S.; Hsueh, F.-K.; Lu, Y.-L.; Sung, P.-J.; Chen, S.-J.; Lo, C.-H.; Lai, C.-H.; Current, Michael I.; Tseng, T.-Y.; Chao, T.-S.; Yang, F.-L.

2012-11-01

63

Paranormal phenomena  

NASA Astrophysics Data System (ADS)

Critical analysis is given of some paranormal phenomena events (UFO, healers, psychokinesis (telekinesis))reported in Moldova. It is argued that correct analysis of paranormal phenomena should be made in the framework of electromagnetism.

Gaina, Alex

1996-08-01

64

Depth profile investigation of ?-FeSi2 formed in Si(1 0 0) by high fluence implantation of 50 keV Fe ion and post-thermal vacuum annealing  

NASA Astrophysics Data System (ADS)

A single phase polycrystalline ?-FeSi2 layer has been synthesized at the near surface region by implantation in Si(1 0 0) of a high fluence (?1017 atoms/cm2) of 50 keV Fe ions and subsequent thermal annealing in vacuum at 800 C. The depth profile of the implanted Fe atoms in Si(1 0 0) were simulated by the widely used transportation of ions in matter (TRIM) computer code as well as by the dynamic transportation of ions in matter code (T-DYN). The simulated depth profile predictions for this heavy ion implantation process were experimentally verified using Rutherford Backscattering Spectrometry (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with Ar-ion etching. The formation of the ?-FeSi2 phase was monitored by X-ray diffraction measurements. The T-DYN simulations show better agreement with the experimental Fe depth profile results than the static TRIM simulations. The experimental and T-DYN simulated results show an asymmetric distribution of Fe concentrated more toward the surface region of the Si substrate.

Lakshantha, Wickramaarachchige J.; Kummari, Venkata C.; Reinert, Tilo; McDaniel, Floyd D.; Rout, Bibhudutta

2014-08-01

65

Vacuum Mechatronics.  

National Technical Information Service (NTIS)

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an incr...

S. Hackwood S. E. Belinski G. Beni

1989-01-01

66

Sputtered lead scandium tantalate thin films: crystallization behaviour during post-deposition annealing  

Microsoft Academic Search

Lead scandium titanate (PST) thin films were deposited by RF dual magnetron sputtering and then annealed either by vacuum furnace or combined rapid thermal annealing (RTA) and furnace anneal. The film structure was investigated by x-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy techniques. Lead loss was more severe using furnace annealing than

Z. Huang; P. P. Donohue; M. A. Todd; J. C. Jones; R. W. Whatmore

2001-01-01

67

A study of rapid photothermal annealing on the electrical properties and reliability of tantalum pentoxide  

Microsoft Academic Search

Rapid photothermal annealing is based on the use of vacuum ultraviolet (VUV) photons as the source of optical energy and tungsten halogen lamps as the source of optical and thermal energy. Tantalum pentoxide (Ta2O5) thin films deposited by thermal metalorganic chemical vapor deposition (MOCVD) have been annealed by RPP and conventional rapid thermal annealing (RTP). As compared to samples annealed

Y. Chen; R. Singh; K. Rajan; D. J. Dumin; S. Deboer; R. P. S. Thakur

1999-01-01

68

Stress relief of tetrahedral amorphous carbon films by post-deposition thermal annealing  

Microsoft Academic Search

The stress relief of tetrahedral amorphous carbon (ta-C) films by post-deposition thermal annealing was investigated. The films were subjected to rapid thermal annealing (RTA) for 2min and conventional furnace annealing (CFA) for 30min. In both cases, the films were annealed in vacuum with argon (410?2Torr) at successive higher temperatures ranging from 500 to 800C. It was found that annealing by

B. K. Tay; X. Shi; E. Liu; S. P. Lau; L. K. Cheah; Z. Sun; J. Shi

1999-01-01

69

Annealing of silicon optical fibers  

NASA Astrophysics Data System (ADS)

The recent realization of silicon core optical fibers has the potential for novel low insertion loss rack-to-rack optical interconnects and a number of other uses in sensing and biomedical applications. To the best of our knowledge, incoherent light source based rapid photothermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination of the silicon core showed a considerable enhancement in the length and amount of single crystallinity post-annealing. Further, shifts in the Raman frequency of the silicon in the optical fiber core that were present in the as-drawn fibers were removed following the RPP treatment. Such results indicate that the RPP treatment increases the local crystallinity and therefore assists in the reduction of the local stresses in the core, leading to more homogenous fibers. The dark current-voltage characteristics of annealed silicon optical fiber diodes showed lower leakage current than the diodes based on as-drawn fibers. Photons in UV and vacuum ultraviolet (VUV) regions play a very important role in improving the bulk and carrier transport properties of RPP-treated silicon optical fibers, and the resultant annealing permits a path forward to in situ enhancement of the structure and properties of these new crystalline core optical fibers.

Gupta, N.; McMillen, C.; Singh, R.; Podila, R.; Rao, A. M.; Hawkins, T.; Foy, P.; Morris, S.; Rice, R.; Poole, K. F.; Zhu, L.; Ballato, J.

2011-11-01

70

Quasineutral hybrid simulation of macroscopic plasma phenomena  

Microsoft Academic Search

A method for solving the quasineutral hybrid plasma equations in two dimensions is presented, using full ion dynamics and inertialess electrons. The method uses a predictor-corrector field solver and is extended to allow plasma-vacuum interfaces of arbitrary shape. A three-region method for treating the plasma-vacuum interfaces makes possible the simulation of slowly evolving phenomena over time scales much longer than

D HARNED

1982-01-01

71

Vacuum Technology  

SciTech Connect

The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

Biltoft, P J

2004-10-15

72

Vacuum mechatronics  

NASA Technical Reports Server (NTRS)

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

1989-01-01

73

Vacuum Virtues  

ERIC Educational Resources Information Center

Upright vacuums, like cars, vary in quality, features and performance. Like automobiles, some uprights are reliable, others may be problematic, and some become a problem as a result of neglect or improper use. So, how do education institutions make an informed choice and, having done so, ensure that an upright vacuum goes the distance? In this

Rathey, Allen

2007-01-01

74

Vacuum regulator  

Microsoft Academic Search

This patent describes a vacuum regulator for automotive vehicles of the type having an engine exhaust system and a computer controlled exhaust gas recirculation system. The vacuum regulator consists of: a housing having separate interconnected upper and lower portions; a solenoid in the housing including a bobbin having a valve seat; a mechanism for defining an inlet for atmospheric air

M. Slavin; R. P. Fontecchio

1986-01-01

75

Vacuum Gauges  

NSDL National Science Digital Library

This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. Semiconductor manufacturing equipment requires the use of many different types of vacuum gauges. Selection is based on range of process operations and production requirements. This MATEC module explores the theory and functionality of vacuum gauges and provides many examples of different types of gauges. The focus is on understanding the operating ranges and application constraints of each type of gauge. Mathematical equations are used to explain calibration, sensitivity, and overall operations of each type of gauge.

2012-11-28

76

Annealing effect on the chemical structure of diamondlike carbon  

Microsoft Academic Search

The effect of annealing in an ultrahigh vacuum on the chemical structure of diamondlike carbon (DLC) was investigated using photoelectron spectroscopy, thermal desorption spectroscopy, electrical resistivity, and micro-Raman spectroscopy measurements. The line shapes of the C 1s photoelectron spectra depended on annealing temperature. The relative intensities of four chemical components in the spectra were quantitatively evaluated: sp3 carbon with carbon-carbon

Susumu Takabayashi; Keishi Okamoto; Hiroyuki Sakaue; Takayuki Takahagi; Tatsuyuki Nakatani

2008-01-01

77

Effects of Annealing on the Magnetic and Structural Properties of FePt Nanoparticles by Chemical Synthesis  

Microsoft Academic Search

In this paper, we have studied the effects of annealing atmospheres on the particle size, the degree of ordering, and the magnetic properties of FePt nanoparticles made by chemical synthesis. Measurements were made on particle assemblies with controlled dimension and thickness. Annealing was done under forming gas and vacuum atmospheres. Particles did not grow much after annealing at 550 ^oC

Hongli Wang; Y. Huang; Y. Zhang; G. Hadjipanayis; D. Weller; A. Simopoulos

2006-01-01

78

Influence of postdeposition annealing on the properties of ZnO films prepared by RF magnetron sputtering  

Microsoft Academic Search

ZnO films were prepared on unheated silicon substrate by RF magnetron sputtering technique. Postdeposition annealing of ZnO films in vacuum were found to improve film structure and electrical characteristics, such as dense structure, smooth surface, stress relief and increasing resistivity. Suitable annealing temperature also reduced loss factor. The correlation between annealing conditions and the physical structure of the films (crystalline

Sheng-Yuan Chu; Walter Water; Jih-Tsang Liaw

2003-01-01

79

Behavior of oxygen in zinc oxide films through thermal annealing and its effect on sheet resistance  

NASA Astrophysics Data System (ADS)

Behavior of oxygen in sputtering deposited ZnO films through thermal annealing and its effect on sheet resistance of the films were investigated. The crystallinities of the ZnO film were improved by post-deposition annealing in vacuum. However, the sheet resistance of ZnO film was dramatically decreased after post-deposition annealing in vacuum at more than 300 C, while O 2 desorbed from the film. The oxygen vacancies which acted as donors were formed by the thermal annealing in vacuum. The sheet resistance of the films was recovered by annealing in oxygen ambient. In this paper, 18O 2 gas as an oxygen isotope was used as the annealing ambient in order to distinguish from 16O, which was constituent atom of the ZnO films. SIMS analysis revealed that 18O diffused into the ZnO film from the top surface by 18O 2 annealing. Therefore oxygen vacancies formed by the post-deposition annealing in vacuum could be compensated by the annealing in oxygen ambient.

Hiramatsu, Takahiro; Furuta, Mamoru; Matsuda, Tokiyoshi; Li, Chaoyang; Hirao, Takashi

2011-04-01

80

Quasineutral hybrid simulation of macroscopic plasma phenomena  

SciTech Connect

A method for solving the quasineutral hybrid plasma equations in two dimensions is presented, using full ion dynamics and inertialess electrons. The method uses a predictor-corrector field solver and is extended to allow plasma-vacuum interfaces of arbitrary shape. A three-region method for treating the plasma-vacuum interfaces makes possible the simulation of slowly evolving phenomena over time scales much longer than the ion cyclotron period. The algorithm is applied to the study of rotational instabilities in theta pinch Vlasov equilibria.

Harned, D.S.

1982-09-01

81

Vacuum Technology: Vacuum Technology III  

NSDL National Science Digital Library

This is a link to a PDF version of lecture slides that discuss gas sources in a vacuum. The presentation explains concepts such as vapor pressure curves, thermal desorption and first and second order desorption. Keywords: Vaporization, desorption, diffusion, permeation, backstreaming

Rack, Philip D.

2012-12-12

82

Superconducting properties of annealed Nb-Al-Ge thin films.  

NASA Technical Reports Server (NTRS)

Discussion of the superconducting transition temperature and other superconducting properties of annealed Nb-Al-Ge thin films which were prepared by sputtering from a 3Nb-0.8Al-0.2Ge cathode. Annealing was performed in a high-vacuum environment maintained at 10 to the minus 9th torr or less, for times and temperatures near the optimum conditions for bulk Nb-Al-Ge. Films with transition temperatures from 12 to 16 K were annealed and in all cases a rise in transition temperature was observed, with the maximum value obtained thus far being 17.5 K. The current carrying capacity values, already substantially higher for unannealed thin films than for the bulk, were raised even further in the annealed samples, indicating that annealing has no detrimental effects on the flux pinning in these films.

Janocko, M. A.; Gavaler, J. R.; Jones, C. K.

1972-01-01

83

On the Debossing, Annealing and Mounting of Bells  

NASA Astrophysics Data System (ADS)

Changes in the frequencies of the musical partials of various types of bells following debossing dismounting/mounting and annealing/quench annealing are reported. Debossing, dismounting and quench annealing lead to frequency drops, while mounting gives rises. Annealing can lead to frequency increases or decreases depending upon the maximum temperature employed and the initial residual stress. Qualitative explanations of these phenomena are given in terms of changes in crown stiffness, internal stress and alloy phase structure. These are supported by the results of X-ray diffraction measurements. Although the effects are all small they can be large enough to be detected by a reasonably musical car. This, together with the fact that the effects cannot be controlled, gives a plausible explanation of why modern bellfounders use vertical lathes for tuning, even with small carillon bells, and do not anneal bells when trying to control warble.

PERRIN, R.; SWALLOWE, G. M.; CHARNLEY, T.; MARSHALL, C.

1999-10-01

84

Structural changes of diamond-like carbon films due to atomic hydrogen exposure during annealing  

NASA Astrophysics Data System (ADS)

We have deposited diamond-like carbon (DLC) films by radio-frequency magnetron sputtering, and have annealed the films under various conditions to investigate the effects of annealing on the structural properties by visible Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. The structural ordering of hydrogenated DLC films occurs during annealing below 400 C in a vacuum and a hydrogen gas atmosphere, while unhydrogenated DLC films are not ordered during annealing even at 700 C. On the other hand, the ordering and the decrease of the sp 3 content are observed for both the films after annealing under an atomic hydrogen exposure. The ordering progresses as the annealing temperature and time are increased. The reduction of the film thickness after annealing is suppressed with increasing annealing temperature. The results suggest that both the preferential etching by atomic hydrogen and the hydrogen evolution encourage the structural changes under an atomic hydrogen exposure.

Nakazawa, H.; Kawabata, T.; Kudo, M.; Mashita, M.

2007-02-01

85

Tuning magnetic properties of yttrium iron garnet film with oxygen partial pressure in sputtering and annealing process  

SciTech Connect

In this paper, the magnetic properties of these films which deposited and annealed at different atmospheres were investigated. The experimental results show that the magnetic properties of yttrium iron garnet films prepared by rf magnetron sputtering method can be tuned with oxygen partial pressure in sputtering and annealing processes. The optimal condition is depositing in atmosphere of R=0 and annealing at 0.5 Pa O{sub 2}, or depositing in atmosphere of R=2% and annealed in vacuum.

Yang Qinghui; Zhang Huaiwu; Wen Qiye; Liu Yingli [State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Xiao, John Q. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

2009-04-01

86

Structural changes of diamond-like carbon films due to atomic hydrogen exposure during annealing  

Microsoft Academic Search

We have deposited diamond-like carbon (DLC) films by radio-frequency magnetron sputtering, and have annealed the films under various conditions to investigate the effects of annealing on the structural properties by visible Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. The structural ordering of hydrogenated DLC films occurs during annealing below 400C in a vacuum and a hydrogen gas atmosphere,

H. Nakazawa; T. Kawabata; M. Kudo; M. Mashita

2007-01-01

87

Frequency Domain Simulated Annealing  

NASA Astrophysics Data System (ADS)

This dissertation presents the feasible extension of simulated annealing into the frequency domain. A mathematical development of the algorithm, proof of the asymptotic convergence, and proof of polynomial-bound execution times substantiate frequency domain annealing as a combinatorial optimization technique. Results obtained from experimental implementation of the algorithm in an adaptive spatial filter application demonstrate the stability and reliability of the algorithm. Additional studies of parameter interdependence and effects facilitate the usage of this technique. Frequency domain annealing overcomes some of the inadequacies of its spatial domain predecessor for large, complex applications such as image processing with multiple grey levels. Adaptive spatial filters using frequency annealing are shown to yield global mean-squared error reduction without the loss of fine details or excessive computation.

Reddick, Wilburn Eugene

88

Study of Precipitation Phenomena in Aluminum Alloys by Positron Annihilation.  

National Technical Information Service (NTIS)

To assess the sensitivity of positron annihilation (PA) to precipitation phenomena, the Doppler broadened PA lineshape was monitored as a function of isochronal annealing steps on a series of quenched aluminum alloys. A study of the Al--Cu system, includi...

W. R. Wampler W. B. Gauster

1979-01-01

89

High-pressure and high-temperature annealing as an activation method for ion-implanted dopants in diamond  

NASA Astrophysics Data System (ADS)

The authors show that high-pressure and high-temperature (HPHT) annealing is very effective for the activation of ion-implanted dopants in diamond. The HPHT annealing condition is located in the thermodynamically stable region for diamond in the phase diagram and is, therefore, much more efficient for the recovery of implantation-induced damage and for the activation of ion-implanted dopants than thermal annealing in vacuum. The B-implanted film after HPHT annealing showed a high mobility of 632 cm2/V s with a sheet hole concentration of 4.81010 cm-2 at 300 K and the doping efficiency of ~7%. The mobility is the highest so far for ion-implanted diamond. In the entire annealing temperature range, the HPHT annealing is more efficient than the thermal annealing in vacuum.

Ueda, K.; Kasu, M.; Makimoto, T.

2007-03-01

90

Volcanic Dust Phenomena  

Microsoft Academic Search

THE phenomena connected with the volcanic dust are undergoing distinct changes. In common with observers in the south of England, I noted the fresh appearance of the dust phenomena in the end of June, especially on June 26, but they were not very striking until August 1. At first the most decidedly volcanic feature was the great corona round the

T. W. Backhouse

1902-01-01

91

Coupled Phenomena in Chemistry.  

ERIC Educational Resources Information Center

Various phenomena in chemistry and biology can be understood through Gibbs energy utilization. Some common phenomena in chemistry are explained including neutralization, hydrolysis, oxidation and reaction, simultaneous dissociation equilibrium of two weak acids, and common ion effect on solubility. (Author/SA)

Matsubara, Akira; Nomura, Kazuo

1979-01-01

92

Recent advances in vacuum sciences and applications  

NASA Astrophysics Data System (ADS)

Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solidliquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

Mozeti?, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kvr, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radi?, N.; Drai?, G.; Bernstorff, S.; Biederman, H.; Kylin, O.; Hanu, J.; Miloevi?, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petri?, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

2014-04-01

93

Galvanomagnetic properties of annealed InSb single crystals  

NASA Astrophysics Data System (ADS)

p-type InSb crystals have been obtained by annealing n-type InSb crystals at 350 C in vacuum (10-5 Torr) for different durations. The dc Hall effect and conductivity studies have shown that the inversion temperature increases with increase in annealing time, whereas the Hall mobility decreases. The ratio of electron to hole mobility b is calculated from the log RH -vs-1/T curve and also from electron and hole concentrations. The ratio b is also calculated theoretically from electron and hole mobilities. The value b obtained from experiments is found to differ from the b calculated theoretically. This discrepancy has been attributed to the scattering of charge carriers by dislocations produced during annealing. Using the Dexter and Seitz mechanism [Phy. Rev. 86, 964 (1952)] the dislocation densities have been estimated in the annealed samples.

Nagabhooshanam, M.; Babu, V. Hari

1980-06-01

94

Effects of Post Dielectric Deposition and Post Metallization Annealing Processes on Metal\\/Dy2O3\\/Si(100) Diode Characteristics  

Microsoft Academic Search

Ultra-high vacuum annealing was investigated for Dy2O3 films deposited on Si(100) substrates. The leakage current of the Dy2O3 films deposited at room temperature (RT) was found to be decreased without any increase of the equivalent oxide thickness (EOT) by the in-situ vacuum annealing method compared to that of the conventional rapid thermal annealing (RTA) in O2. The negative flat-band voltage

Shun-ichiro Ohmi; Hiroyuki Yamamoto; Junichi Taguchi; Kazuo Tsutsui; Hiroshi Iwai

2004-01-01

95

Topological Anderson insulator phenomena  

NASA Astrophysics Data System (ADS)

We study the nature of the disorder-induced quantized conductance, i.e., the phenomena of topological Anderson insulator (TAI). The disorder effect in several different systems where the anomalous Hall effect exists is numerically studied using the tight-binding Hamiltonian. It is found that the TAI phenomena can also exist in the modified Dirac model where the quadratic corrections k2?z are included and the electron-hole symmetry is kept. These phenomena also occur in the graphene system with the next-nearest-neighbor coupling and the staggered sublattice potential. For the graphene sheet with Rashba spin-orbit interaction as well as an exchange field, a precursor of TAI is observed. A comparison between the localization length of the two-dimensional ribbon and two-dimensional cylinder structures clearly reveals the topological nature of these phenomena. Furthermore, analysis on the local current density in anomalous quantum Hall systems where the TAI phenomena may or may not arise reveals the nature of TAI phenomena. In the presence of small disorders, the conductance is not quantized and the bulk and edge states coexist in the system. As disorder strength increases, the bulk state is quickly destroyed, while the robust edge state may survive. When the edge state is robust enough to sustain the strong disorder that completely kills the bulk state, TAI phenomena arise.

Xing, Yanxia; Zhang, Lei; Wang, Jian

2011-07-01

96

QED vacuum loops and vacuum energy  

NASA Astrophysics Data System (ADS)

A QED-based "bootstrap" mechanism is suggested as a possible source of vacuum energy. In place of the conventional assumption that the vacuum expectation value of the current operator j ? vanishes in the absence of a classical, external field, one notes the possibility that, on very small scales, the vacuum fluctuations can generate an equation for an effective, C-number giving rise to a finite and computable vacuum energy.

Fried, H. M.; Gabellini, Y.

2013-12-01

97

Deterministic annealing EM algorithm.  

PubMed

This paper presents a deterministic annealing EM (DAEM) algorithm for maximum likelihood estimation problems to overcome a local maxima problem associated with the conventional EM algorithm. In our approach, a new posterior parameterized by `temperature' is derived by using the principle of maximum entropy and is used for controlling the annealing process. In the DAEM algorithm, the EM process is reformulated as the problem of minimizing the thermodynamic free energy by using a statistical mechanics analogy. Since this minimization is deterministically performed at each temperature, the total search is executed far more efficiently than in the simulated annealing. Moreover, the derived DAEM algorithm, unlike the conventional EM algorithm, can obtain better estimates free of the initial parameter values. We also apply the DAEM algorithm to the training of probabilistic neural networks using mixture models to estimate the probability density and demonstrate the performance of the DAEM algorithm. PMID:12662837

Ueda, N; Nakano, R

1998-03-01

98

Science and Paranormal Phenomena  

SciTech Connect

In order to ground my approach to the study of paranormal phenomena, I first explain my operational approach to physics, and to the ''historical'' sciences of cosmic, biological, human, social and political evolution. I then indicate why I believe that ''paranormal phenomena'' might-but need not- fit into this framework. I endorse the need for a new theoretical framework for the investigation of this field presented by Etter and Shoup at this meeting. I close with a short discussion of Ted Bastin's contention that paranormal phenomena should be defined as contradicting physics.

Noyes, H. Pierre

1999-06-03

99

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce  

Microsoft Academic Search

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporationboiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, massaverage temperature, the weight

Su-Yan He; Yun-Fei Li

2008-01-01

100

Experiments on Annealed Aluminum.  

National Technical Information Service (NTIS)

This investigation is a study of the quasi-static stress-strain relation for the case of biaxial stress in annealed commercially pure aluminum, and its implications with respect to the speed of propagation of disturbances caused by incremental stresses. T...

M. J. Kenig

1965-01-01

101

Atom probe, AFM, and STM studies on vacuum-fired stainless steels  

Microsoft Academic Search

The surface morphology of grades 304L and 316LN stainless steels, after low-temperature bake-out process and vacuum annealing, has been studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). The local elemental composition on the surface before and after thermal treatment has been investigated by atom probe (AP) depth profiling measurements. After vacuum annealing, AFM and STM show significant

A. Stupnik; P. Frank; M. Leisch

2009-01-01

102

The Vacuum Bubble Nucleation  

SciTech Connect

We study the nucleation of a vacuum bubble via the vacuum-to-vacuum tunneling transition in curved spacetime. We consider Coleman-de Luccia's semiclassical approximation at zero temperature in pure Einstein theory of gravity and the theory with nonminimal coupling. We discuss the dynamics of a nucleated vacuum bubble.

Lee, Bum-Hoon [Department of Physics and Center for Quantum Spacetime, Sogang University Seoul 121-742 (Korea, Republic of); Lee, Wonwoo [Center for Quantum Spacetime, Sogang University, Seoul 121-742 (Korea, Republic of)

2009-07-10

103

Photoluminescence Characteristics of Mn- and Pr-doped ZnS Nanoparticles Optically Annealed with UV Illumination  

NASA Astrophysics Data System (ADS)

Undoped, Mn-doped, Pr-doped, and Mn- and Pr-codoped ZnS nanoparticles were synthesized by a wet chemical method, and these nanoparticles were optically annealed in air or vacuum. In the photoluminescence (PL) spectra of the optically annealed nanoparticles, a sulfur-vacancy-related PL band at around 420 nm, a PL band associated with the 4T1?6A1 transition of Mn2+, and PL peaks associated with Pr-related complexes were investigated during optical annealing. The integrated PL intensities for the nanoparticles annealed in air increased more markedly with the optical annealing time than those for the nanoparticles annealed in vacuum. This increase may be explained by the photooxidation of the surface, the enhancement of the crystal quality, and the gradual diffusion of luminescent ions into the crystal lattice.

Lee, Jun Woo; Cho, Kyoungah; Kim, Hyunsuk; Kim, Jin-Hyoung; Park, Byoungjun; Noh, Taeyong; Kim, Sung Hyun; Kim, Sangsig

2005-10-01

104

[Effects of different annealing conditions on the photoluminescence of nanoporous alumina film].  

PubMed

The nanoporous alumina films were prepared by two-step anodic oxidation in 0.5 mol L-1 oxalic acid electrolyte at 40 V. Photoluminescence (PL) of nanoporous alumina films was investigated under different annealing atmosphere and different temperature. The authors got three results about the PL measurements. In the same annealing atmosphere, when the annealling temperature T< or =600 degreeC, the intensity of the PL peak increases with elevated annealing temperature and reaches a maximum value at 500 degreeC, but the intensity decreases with a further increase in the annealing temperature, and the PL peak intensity of samples increases with the increase in the annealing temperature when the annealling temperature T> or =800 degreeC. In the different annealling atmosphere, the change in the photoluminescence peak position for nanoporous alumina films with the increase in the annealing temperature is different: With the increase in the annealling temperature, the PL peak position for the samples annealed in air atmosphere is blue shifted, while the PL peak position for the samples annealed in vacuum atmosphere will not change. The PL spectra of nanoporous alumina films annealed at 1100 degreeC in air atmosphere can be de-convoluted by three Gaussian components at an excitation wavelength of 350 nm, with bands centered at 387, 410 and 439 nm, respectively. These results suggest that there might be three luminescence centers for the PL of annealed alumina films. At the same annealling temperature, the PL peak intensity of samples annealed in air atmosphere is stronger than that annealed in the vacuum. Based on the experimental results and the X-ray dispersive energy spectrum (EDS) combined with infrared reflect spectra, the luminescence mechanisms of nanoporous alumina films are discussed. There are three luminescence centers in the annealed nanoporous alumina films, which originate from the F center, F+ center and the center associated with the oxalic impurities. The effects of different annealing conditions on the photoluminescence of nanoporous alumina film are reasonably explained. PMID:24611369

Xie, Ning; Ma, Kai-Di; Shen, Yi-Fan; Wang, Qian

2013-12-01

105

Natural vacuum electronics  

NASA Technical Reports Server (NTRS)

The ambient natural vacuum of space is proposed as a basis for electron valves. Each valve is an electron controlling structure similiar to a vacuum tube that is operated without a vacuum sustaining envelope. The natural vacuum electron valves discussed offer a viable substitute for solid state devices. The natural vacuum valve is highly resistant to ionizing radiation, system generated electromagnetic pulse, current transients, and direct exposure to space conditions.

Leggett, Nickolaus

1990-01-01

106

Germanium detector vacuum encapsulation  

NASA Technical Reports Server (NTRS)

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

107

Vacuum polarization and Hawking radiation  

NASA Astrophysics Data System (ADS)

Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.

Rahmati, Shohreh

108

Studies on the photoconductivity of vacuum deposited ZnTe thin films  

Microsoft Academic Search

The present paper reports the analysis of photoconductivity of vacuum deposited zinc telluride (ZnTe) thin films as a function of substrate temperature and post-deposition annealing. Detailed analyses were first carried out to understand the effect of substrate temperature and annealing on the structure, composition, optical and electrical properties of the films. The films deposited at elevated substrate temperatures showed faster

Gowrish K. Rao; Kasturi V. Bangera; G. K. Shivakumar

2010-01-01

109

Stress-induced phenomena in metallization  

SciTech Connect

These proceedings represent papers presented at the Second International Workshop on Stress Induced Phenomena in Metallization held on March 29-31, 1993 at the University of Texas at Austin, U.S.A. The papers included in this volume discuss stress-induced void formation and electromigration failures in narrow-line inter-connect metallization. The results presented have a direct relevance to VLSI fabrication technology. The symposium was sponsored by the American Vacuum Society, the Japanese Society of Applied Physics and the University of Texas at Austin. (AIP)

Ho, P.S. (ed.) (University of Texas at Austin (United States)); Li, C.Y. (ed.) (Cornell University (United States)); Totta, P. (ed.) (IBM Microelectronics Division (United States))

1994-01-01

110

Wear of Steel and Ti6Al4V Rollers in Vacuum  

NASA Technical Reports Server (NTRS)

This investigation was prompted by results of a qualification test of a mechanism to be used for the James Webb Space Telescope. Post-test inspections of the qualification test article revealed some loose wear debris and wear of the steel rollers and the mating Ti6Al4V surfaces. An engineering assessment of the design and observations from the tested qualification unit suggested that roller misalignment was a controlling factor. The wear phenomena were investigated using dedicated laboratory experiments. Tests were done using a vacuum roller rig for a range of roller misalignment angles. The wear in these tests was mainly adhesive wear. The measured wear rates were highly correlated to the misalignment angle. For all tests with some roller misalignment, the steel rollers lost mass while the titanium rollers gained mass indicating strong adhesion of the steel with the titanium alloy. Inspection of the rollers revealed that the adhesive wear was a two-way process as titanium alloy was found on the steel rollers and vice versa. The qualification test unit made use of 440F steel rollers in the annealed condition. Both annealed 440F steel rollers and hardened 440C rollers were tested in the vacuum roller rig to investigate possibility to reduce wear rates and the risk of loose debris formation. The 440F and 440C rollers had differing wear behaviors with significantly lesser wear rates for the 440C. For the test condition of zero roller misalignment, the adhesive wear rates were very low, but still some loose debris was formed

Krantz, Timothy L.; Shareef, Iqbal

2012-01-01

111

FePt nanoparticles formed in Al2O3 by ion beam synthesis: Annealing environment effects  

Microsoft Academic Search

The properties of FePt nanoparticles formed by the implantation of Fe+Pt into c-axis-oriented Al2O3 single crystals followed by thermal annealing are shown to be strongly dependent on the annealing environment. Annealing in a reducing environment (flowing Ar+4% H2, or ultrahigh vacuum) gives rise to ferromagnetic FePt nanoparticles with the L10 structure and very high magnetic coercivity (greater than 20 kOe).

C. W. White; S. P. Withrow; J. M. Williams; J. D. Budai; A. Meldrum; K. D. Sorge; J. R. Thompson; L. A. Boatner

2004-01-01

112

Stress pulse phenomena  

SciTech Connect

This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.

McGlaun, M.

1993-08-01

113

Imaging of snapping phenomena.  

PubMed

Snapping phenomena result from the sudden impingement between anatomical and/or heterotopical structures with subsequent abrupt movement and noise. Snaps are variously perceived by patients, from mild discomfort to significant pain requiring surgical management. Identifying the precise cause of snaps may be challenging when no abnormality is encountered on routinely performed static examinations. In this regard, dynamic imaging techniques have been developed over time, with various degrees of success. This review encompasses the main features of each imaging technique and proposes an overview of the main snapping phenomena in the musculoskeletal system. PMID:22744321

Guillin, R; Marchand, A J; Roux, A; Niederberger, E; Duvauferrier, R

2012-10-01

114

Transport phenomena in nanofluidics  

Microsoft Academic Search

The transport of fluid in and around nanometer-sized objects with at least one characteristic dimension below 100nm enables the occurrence of phenomena that are impossible at bigger length scales. This research field was only recently termed nanofluidics, but it has deep roots in science and technology. Nanofluidics has experienced considerable growth in recent years, as is confirmed by significant scientific

Reto B. Schoch; Jongyoon Han; Philippe Renaud

2008-01-01

115

Sputtered lead scandium tantalate thin films: crystallization behaviour during post-deposition annealing  

NASA Astrophysics Data System (ADS)

Lead scandium titanate (PST) thin films were deposited by RF dual magnetron sputtering and then annealed either by vacuum furnace or combined rapid thermal annealing (RTA) and furnace anneal. The film structure was investigated by x-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy techniques. Lead loss was more severe using furnace annealing than the combined RTA and furnace anneal. The annealed films were characterized by the presence of voids and exhibited relaxor ferroelectric characteristics. PST perovskite crystal grains were found to co-exist with pyrochlore matrix in the furnace-only annealed films, whilst in RTA annealed films no apparent pyrochlore morphology was observed in the TEM image. Lead was found to diffuse through the bottom electrode Pt layer during the annealing. Films treated by combining RTA and furnace annealing have shown pyroelectric coefficients under field of up to 500 C m-2 K-1, a dielectric loss of below 0.007 and a merit figure for thermal detection of 2.510-5 Pa-1/2.

Huang, Z.; Donohue, P. P.; Todd, M. A.; Jones, J. C.; Whatmore, R. W.

2001-11-01

116

Educational Vacuum Trainers  

NSDL National Science Digital Library

Have you inherited a bell jar vacuum system and are scratching your head over how to set it up or are unsure of its operations or capabilities? Or do you want to do more with your bell jar vacuum? The forum on Bell Jar Vacuums - with the topic Vacuum Trainers can help you. The intent of this forum is for this to be a place where technical issues, classroom exercises, activities, etc. can be discussed. There's no endorsement by manufacturers and commercial issues are off limits. Steve Hansen (bell jar expert) gives some brief descriptions of the vacuum trainers that are or have been available over the past decade or so - Varian, MKS, Science Source, American Vacuum Society. Links are provided to various data sheets, articles and online exercises. Steve, the forum moderator has experience in all of these.Keywords: vacuum, "vacuum trainer","bell jar" and/or belljar, MKSVarian, VPAL, VTS, sputtering, plasma

Hansen, Steve

2012-07-31

117

Optimizing process vacuum condensers  

SciTech Connect

Vacuum condensers play a critical role in supporting vacuum processing operations. Although they may appear similar to atmospheric units, vacuum condensers have their own special designs, considerations and installation needs. By adding vacuum condensers, precondensers and intercondensers, system cost efficiency can be optimized. Vacuum-condensing systems permit reclamation of high-value product by use of a precondenser, or reduce operating costs with intercondensers. A precondenser placed between the vacuum vessel and ejector system will recover valuable process vapors and reduce vapor load to an ejector system--minimizing the system`s capital and operating costs. Similarly, an intercondenser positioned between ejector stages can condense motive steam and process vapors and reduce vapor load to downstream ejectors as well as lower capital and operating costs. The paper describes vacuum condenser systems, types of vacuum condensers, shellside condensing, tubeside condensing, noncondensable gases, precondenser pressure drop, system interdependency, equipment installation, and equipment layout.

Lines, J.R.; Tice, D.W. [Graham Mfg. Co., Batavia, NY (United States)

1997-09-01

118

Vacuum Probe Surface Sampler.  

National Technical Information Service (NTIS)

A vacuum probe surface sampler for rapidly sampling relatively large surface areas which possess relatively light loading densities of microorganisms, drug particles or the like is described. A vacuum head having a hollow handle connected to a suitable va...

B. A. Zahlava

1971-01-01

119

High temperature annealing effects on low energy iron implanted SiO 2  

Microsoft Academic Search

15keV Fe ions were implanted into a thermally grown silica film with a fluence of 11016at.\\/cm2 resulting in a near Gaussian concentration profile peaking at 8 at.% about 15nm under the surface. High vacuum (?10?7mbar) furnace annealing and electron beam annealing at high temperature resulted in diffusion of Fe inside the oxide film. Segregation of Fe atoms at the SiO2

J. Kennedy; J. Leveneur; A. Markwitz

120

Effects of post-diffusion annealing on Zn-diffused GaAs:Si  

Microsoft Academic Search

After Zn diffusion into Si-doped GaAs (n≊1.51018 cm?3), the Zn-diffused samples are annealed under different conditions: (i) in vacuum, (ii) in arsenic vapor, and (iii) with a Si3N4 mask capping the sample surface. The Zn concentration profiles obtained by secondary-ion-mass spectroscopy and the photoluminescence (PL) spectra taken at different depths below the sample surface are studied in detail. After annealing

Nguyen Hong Ky; F. K. Reinhart; B. Blanchard; J. C. Pfister

1993-01-01

121

The effect of annealing on mechanical and tribological properties of diamond-like carbon multilayer films  

Microsoft Academic Search

The diamond-like carbon (DLC) multilayer films have been deposited by plasma CVD deposition onSi wafer substrate. The deposited films have then been post-annealed in vacuum at 250 C for 2 h. Changes in internal stress, hardness, critical load, friction coefficient and wear have been investigated toassess the influence of annealing on mechanical and tribological properties of DLC multilayer films. At

W. Zhang; A. Tanaka; K. Wazumi; Y. Koga; B. S. Xu

2004-01-01

122

Synthesis of new carbon-nitrogen nanoclusters by annealing diamond-like carbon films in nitrogen  

Microsoft Academic Search

Diamond-like carbon (DLC) films were prepared by ion-beam sputtering of a graphite target and annealed at a temperature of\\u000a 400C in vacuum and nitrogen with oxygen admixture (about 12%). The Raman and optical absorption spectra of these films were\\u000a studied. Anomalous changes in the DLC films annealed in nitrogen were detected. The optical absorptance of films in the visible\\u000a range

I. A. Faizrakhmanov; V. V. Bazarov; N. V. Kurbatova; I. B. Khaibullin; A. L. Stepanov

2003-01-01

123

Evolution of microstructure and nanomechanical behavior of diamond-like carbon films at high temperature annealing  

Microsoft Academic Search

The microstructure and nanomechanical behavior of diamond like carbon (DLC) films has been investigated at high temperature annealing. The DLC films with 250 nm thickness were deposited on the crystalline silicon (c-Si) substrate using ultra-high-vacuum ion beam sputtering and post thermal annealing at high temperature up to 900C for 0.5-1.5 hours. Raman spectra showed that the as-deposited DLC film contained

B. H. Wu; C. K. Chung; C. W. Lai

2009-01-01

124

Blood flow multiscale phenomena.  

PubMed

The cardiovascular disease is one of most frequent cause deaths in modern society. The objective of this work is analyse the effect of dynamic vascular geometry (curvature, torsion, bifurcation) and pulsatile blood nature on secondary flow, wall shear stress and platelet deposition. The problem was examined as multi-scale physical phenomena using perturbation analysis and numerical modelling. The secondary flow determined as influence pulsatile pressure, vascular tube time-dependent bending and torsion on the main axial flow. Bifurcation and branching phenomena are analysed experimentally through, blood-like fluid pulsatile flow across elastic rubber-like Y-model model. The problem complex geometry near branching in platelet deposit modelling is resolved numerically as Falker-Skan flow. PMID:17847933

Agi?, Ante; Mijovi?, Budimir; Nikoli?, Tatjana

2007-06-01

125

Self-annealing characterization of electroplated copper films  

Microsoft Academic Search

Self-annealing of electro-chemically deposited copper films is described and studied, with a focus on the effect of process parameters like concentration of the organic additives, current density or thickness of plated copper. Sheet resistance and stress have been monitored and a non-correlated behavior has been observed for these two film characteristics, indicating that other phenomena than the grain growth typically

S Lagrange; S. H Brongersma; M Judelewicz; A Saerens; I Vervoort; E Richard; R Palmans; K Maex

2000-01-01

126

Influence of the annealing atmosphere on structural, optical and magnetic properties of Co-doped ZnO microrods  

NASA Astrophysics Data System (ADS)

We have investigated the effects of annealing in vacuum and oxygen atmosphere at 500 C on the structural, optical and magnetic properties of Co-doped ZnO microrods deposited by a spray pyrolysis method on glass substrates. The stoichiometry of the as-deposited films was determined as Zn0.91Co0.09O using X-ray photoelectron spectroscopy. X-ray diffraction pattern of the as-deposited and annealed films exhibited wurtzite crystal structure with a strong (0 0 2) preferred orientation. Surface morphology of the films obtained by scanning electron microscopy revealed that as-deposited Zn0.91Co0.09O films had hexagonal shaped rods with submicron size diameter and no significant changes were detected in the rod morphology and rod diameters with annealing. Photoluminescence and X-ray diffraction results showed a better crystalline quality obtained with the post-treatment in oxygen compared to that in vacuum. Annealing in vacuum enhanced the room temperature magnetization, which might be associated with the increased amount of oxygen vacancies created due to the out-diffusion of oxygen atoms, during the post-treatment in vacuum. Measurements at a constant magnetic field of 1 kOe in the temperature range 10-300 K showed a higher magnetization and a higher rate of increase in magnetization with decreasing temperatures for the vacuum-annealed sample compared to as-deposited and oxygen-annealed sample.

Aksu, S.; Bacaksiz, E.; Y?lmaz, S.; Polat, I.; Altunba?, M.; Trksoy, M.; Topkaya, R.; zdo?an, K.

2012-04-01

127

Lunar transient phenomena  

NASA Astrophysics Data System (ADS)

Lunar transient phenomena (LTP) sightings are classified into five categories: brightenings, darkenings, reddish colorations, bluish colorations, and obscurations. There is evidence that the remaining LTP's are of lunar origin. A substantial number of sightings are independently confirmed. They have been recorded on film and spectrograms, as well as with photoelectric photometers and polarization equipment. It suggested that the LTP's may be gentle outgassings of less-than-volcanic proportions.

Cameron, W. S.

1991-03-01

128

Indium out-diffusion in Al2O3/InGaAs stacks during anneal at different ambient conditions  

NASA Astrophysics Data System (ADS)

Indium out-diffusion during anneal enhances leakage currents in metal/dielectric/InGaAs gate stacks. In this work, we study the influence of ambient conditions during anneal on indium out-diffusion in Al2O3/InGaAs structures, prior to the gate metal deposition. Using X-ray photoemission spectroscopy and time of flight secondary ions mass spectrometry, we observed much lower indium concentrations in the Al2O3 layer following vacuum and O2 anneals compared to forming gas or nitrogen anneals. The electrical characteristics of the Ni/Al2O3/InGaAs gate stack following these pre-metallization anneals as well as after subsequent post metallization anneals are presented. Possible explanations for the role of the annealing ambient conditions on indium out-diffusion are presented.

Krylov, Igor; Winter, Roy; Ritter, Dan; Eizenberg, Moshe

2014-06-01

129

The Classical Vacuum.  

ERIC Educational Resources Information Center

The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of

Boyer, Timothy H.

1985-01-01

130

Visual hallucinations as release phenomena  

Microsoft Academic Search

Whereas episodic, stereotype hallucinations represent irritative phenomena, analogous to ictal attacks, the continuous, variable hallucinations are interpreted as release phenomena resulting from loss or suppression of the normal visual input. The latter have only limited topical significance.

David G. Cogan

1973-01-01

131

Wolf-Rayet phenomena  

NASA Technical Reports Server (NTRS)

The properties of stars showing Wolf-Rayet phenomena are outlined along with the direction of future work. Emphasis is placed on the characteristics of W-R spectra. Specifically the following topics are covered: the absolute visual magnitudes; the heterogeneity of WN spectra; the existence of transition type spectra and compositions the mass loss rates; and the existence of very luminous and possibly very massive W-R stars. Also, a brief overview of current understanding of the theoretical aspects of stellar evolution and stellar winds and the various scenarios that have been proposed to understand W-R spectra are included.

Conti, P. S.

1982-01-01

132

Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities  

SciTech Connect

Ongoing studies at Fermilab investigate whether dislocations and other factors instigate pitting during cavity electropolishing (EP), despite careful processing controls and the inherent leveling mechanism of EP itself. Here, cold-worked niobium coupons, which exhibited increased tendencies for pitting in our past study, were annealed in a high vacuum furnace and subsequently processed by EP. Laser confocal scanning microscopy and special defect counting algorithms were used to assess the population of pits formed. Hardness measurements indicated that annealing for 2 hours at 800 C produced recovery, whereas annealing for 12 hours at 600 C did not, as is consistent with known changes for cavities annealed in a similar way. The 800 C anneal was effective in some cases but not others, and we discuss reasons why tendencies for pitting remain. We discuss implications for cavities and continued work to understand pitting.

Cooley, L.D.; Hahn, E.; Hicks, D.; Romanenko, A.; Schuessler, R.; Thompson, C.; /Fermilab

2011-06-08

133

Critical Acceleration and Quantum Vacuum  

NASA Astrophysics Data System (ADS)

Little is known about the physics frontier of strong acceleration; both classical and quantum physics need further development in order to be able to address this newly accessible area of physics. In this lecture we discuss what strong acceleration means and possible experiments using electron-laser collisions and, data available from ultra-relativistic heavy ion collisions. We review the foundations of the current understanding of charged particle dynamics in presence of critical forces and discuss the radiation reaction inconsistency in electromagnetic theory and the apparent relation with quantum physics and strong field particle production phenomena. The role of the quantum vacuum as an inertial reference frame is emphasized, as well as the absence of such a `Machian' reference frame in the conventional classical limit of quantum field theory.

Rafelski, Johann; Labun, Lance

2013-12-01

134

High power, high frequency, vacuum flange  

DOEpatents

An improved waveguide flange is disclosed for high power operation that helps prevent arcs from being initiated at the junctions between waveguide sections. The flanges at the end of the waveguide sections have counter bores surrounding the waveguide tubes. When the sections are bolted together the counter bores form a groove that holds a fully annealed copper gasket. Each counterbore has a beveled step that is specially configured to insure the gasket forms a metal-to-metal vacuum seal without gaps or sharp edges. The resultant inner surface of the waveguide is smooth across the junctions between waveguide sections, and arcing is prevented.

Felker, B.; McDaniel, M.R.

1993-03-23

135

Breakdown phenomena in high power klystrons  

SciTech Connect

In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism for the puncturing will be presented. 9 refs., 5 figs., 3 tabs.

Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V.; Lee, T.G.

1988-03-01

136

Irradiate-anneal screening of total dose effects in semiconductor devices  

NASA Technical Reports Server (NTRS)

Judicious choice of radiation dose and parameter change acceptance criteria, absence of anomalous anneal phenomena, and absence of anomalous reirradiation effects are recognized as essential for a successful irradiation-anneal (IRAN) screening procedure to ensure that no device will fall, upon reirradiation, above parametric limits assigned for the worst case application. Reirradiation and irradiation-anneal behavior of various semiconductor devices are compared and those that do not lend themselves to IRAN screening are singled out. Information needed to judge the suitability of an IRAN type screening program is detailed. Reasons for success of the limited IRAN screening of flight parts for the Mariner Jupiter/Saturn (MJS '77) spacecraft are indicated.

Stanley, A. G.; Price, W. E.

1976-01-01

137

Electron-irradiation enhanced photoluminescence from GaInNAs/GaAs quantum wells subject to thermal annealing  

SciTech Connect

Electron irradiation of a 1.3-{mu}m-GaInNAs/GaAs multi-quantum-well heterostructure, grown by molecular beam epitaxy and subsequently rapid-thermal annealed, is found to induce much stronger photoluminescence than what is observed for an identical as-grown sample upon annealing. Annealing of the irradiated sample also causes a small additional spectral blueshift and reduces alloy potential energy fluctuations at the conduction band minimum. These irradiation-related phenomena are accompanied by small but discernable changes in x-ray diffraction features upon annealing, which indicate compositional and/or structural changes in the quantum wells.

Pavelescu, E.-M.; Gheorghiu, A.; Dumitrescu, M.; Tukiainen, A.; Jouhti, T.; Hakkarainen, T.; Kudrawiec, R.; Andrzejewski, J.; Misiewicz, J.; Tkachenko, N.; Dhaka, V.D.S.; Lemmetyinen, H.; Pessa, M. [Optoelectronics Research Centre, P.O. Box 692, and Institute of Materials Chemistry, P.O. Box 541, Tampere University of Technology, 33101 Tampere (Finland); Hyperion University, Calea Calarasi 169, 74118 Bucharest (Romania); Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, 33101 Tampere (Finland); Institute of Physics, Wroclaw University of Technology Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 541, 33101 Tampere (Finland); Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, 33101 Tampere (Finland)

2004-12-20

138

Weld pool phenomena  

SciTech Connect

During welding, the composition, structure and properties of the welded structure are affected by the interaction of the heat source with the metal. The interaction affects the fluid flow, heat transfer and mass transfer in the weld pool, and the solidification behavior of the weld metal. In recent years, there has been a growing recognition of the importance of the weld pool transport processes and the solid state transformation reactions in determining the composition, structure and properties of the welded structure. The relation between the weld pool transport processes and the composition and structure is reviewed. Recent applications of various solidification theories to welding are examined to understand the special problems of weld metal solidification. The discussion is focussed on the important problems and issues related to weld pool transport phenomena and solidification. Resolution of these problems would be an important step towards a science based control of composition, structure and properties of the weld metal.

David, S.A.; Vitek, J.M.; Zacharia, T. [Oak Ridge National Lab., TN (United States); DebRoy, T. [Pennsylvania State Univ., University Park, PA (United States)

1994-09-01

139

Vacuum probe surface sampler  

NASA Technical Reports Server (NTRS)

A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

Zahlava, B. A. (inventor)

1973-01-01

140

Reactor vessel annealing system  

DOEpatents

A system for annealing a vessel (14) in situ by heating the vessel (14) to a defined temperature, composed of: an electrically operated heater assembly (10) insertable into the vessel (14) for heating the vessel (14) to the defined temperature; temperature monitoring components positioned relative to the heater assembly (10) for monitoring the temperature of the vessel (14); a controllable electric power supply unit (32-60) for supplying electric power required by the heater assembly (10); a control unit (80-86) for controlling the power supplied by the power supply unit (32-60); a first vehicle (2) containing the power supply unit (32-60); a second vehicle (4) containing the control unit (80-86); power conductors (18,22) connectable between the power supply unit (32-60) and the heater unit (10) for delivering the power supplied by the power supply unit (32-60) to the heater assembly (10); signal conductors (20,24) connectable between the temperature monitoring components and the control unit (80-86) for delivering temperature indicating signals from the temperature monitoring components to the control unit (80-86); and control conductors (8) connectable between the control unit (80-86) and the power supply unit (32-60) for delivering to the power supply unit (32-60) control signals for controlling the level of power supplied by the power supply unit (32-60) to the heater assembly (10).

Miller, Phillip E. (Greensburg, PA); Katz, Leonoard R. (Pittsburgh, PA); Nath, Raymond J. (Murrysville, PA); Blaushild, Ronald M. (Export, PA); Tatch, Michael D. (Randolph, NJ); Kordalski, Frank J. (White Oak, PA); Wykstra, Donald T. (Pittsburgh, PA); Kavalkovich, William M. (Monroeville, PA)

1991-01-01

141

Study on effect of annealing conditions on structural, magnetic and superconducting properties of MgB2 bulk samples  

NASA Astrophysics Data System (ADS)

Effect of annealing conditions on structural, magnetic and superconducting properties of Magnesium Diboride (MgB2) bulk superconductor samples prepared by solid state route method are compared. The samples are made by taking Magnesium and Boron powders in stoichiometric ratio, grounded well and pelletized at pressure of about 10Tonnes. These pellets are annealed in both Argon and vacuum environment separately up to 800c for two hours. Both the samples show clear superconducting transition at Tc 38 k. This is further conformed by AC/DC magnetization (M-T), Resistivity [? (T, H)] measurements under magnetic field up to 14 Tesla as well. Rietveld refinement of X-ray diffraction of both samples conformed the MgB2 phase formation with P6/mmm space group symmetry. Scanning Electron Microscopy images of the surface revile more agglomeration of grains in case of Argon annealed samples. This result in more critical current density (Jc) of Argon annealed samples than vacuum annealed one calculated from Bean's critical state model. This high Jc is explained in terms of more inter grain connectivity for Argon annealed sample than vacuum annealed sample.

Phaneendra, Konduru; Asokan, K.; Awana, V. P. S.; Sastry, S. Sreehari; Kanjilal, D.

2014-04-01

142

Compact vacuum insulation embodiments  

Microsoft Academic Search

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom

D. K. Benson; T. F. Potter

1992-01-01

143

Compact vacuum insulation  

Microsoft Academic Search

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom

David K. Benson; Thomas F. Potter

1993-01-01

144

Working in a Vacuum  

ERIC Educational Resources Information Center

In this article, the author discusses several myths about vacuum cleaners and offers tips on evaluating and purchasing this essential maintenance tool. These myths are: (1) Amps mean performance; (2) Everyone needs high-efficiency particulate air (HEPA): (3) Picking up a "bowling ball" shows cleaning power; (4) All vacuum bags are the same; (5)

Rathey, Allen

2005-01-01

145

Study of Vacuum Welding.  

National Technical Information Service (NTIS)

Vacuum cold welding and shear friction of several engineering materials was studied at extremely high vacuum levels above 10 to the -12th power torr in the temperature range 90 to 260 C with interface contact stresses up to 1000 psi. The effect of surface...

M. J. Hordon J. R. Roehrig

1967-01-01

146

Vacuuming radioactive sludge  

SciTech Connect

Vacuuming an estimated 55 cubic yards of radioactive sludge from the floor of Hanford's K East Basin was a complicated process. Workers stood on grates suspended above the 20-foot deep basin and manipulated vacuuming equipment at the end of long poles--using underwater cameras to guide their work.

2006-10-16

147

Vacuum Probe Surface Sampler.  

National Technical Information Service (NTIS)

A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacu...

B. A. Zahlava

1973-01-01

148

Vacuum driven accelerated expansion  

Microsoft Academic Search

It has been shown that an improved estimation of quantum vacuum energy can yield not only acceptable but also experimentally sensible results. The very idea consists in a straightforward extraction of gravitationally interacting part of the full quantum vacuum energy by means of gauge transformations. The implementation of the idea has been performed in the formalism of effective action, in

B. Broda; P. Bronowski; Marcin Ostrowski; Micha? Szanecki

2008-01-01

149

Stellarator Helical Vacuum Vessel.  

National Technical Information Service (NTIS)

A design study of a stainless steel, heavy wall, helically shaped vacuum torus has been made for use in a proposed Stellarator configuration. The study concerns itself with the shape of the vacuum vessel and the division of the vessel into components that...

E. J. Yavornik

1983-01-01

150

Vacuum alignment in technicolor theories: The technifermion sector  

Microsoft Academic Search

We have carried out numerical studies of vacuum alignment in technicolor models of electroweak and flavor symmetry breaking. The goal is to understand alignment implications for strong and weak CP nonconservation in quark interactions. In this first part, we restrict our attention to the technifermion sector of simple models. We find several interesting phenomena, including (1) the possibility that all

Tongu Rador; Estia Eichten

2000-01-01

151

Physics of high-current interruption of vacuum circuit breakers  

Microsoft Academic Search

The present state of knowledge concerning the physical phenomena of high-current interruption with vacuum interrupters (VI) is reviewed. Two arc control methods, application of externally applied axial magnetic field (AMF) or transverse magnetic field (TMF), are available to distribute the heat flux from arc to contacts homogeneously over contact surface, to avoid local overheating. AMF spreads the arc at fixed

Ekkehard Schade

2005-01-01

152

Effect of annealing on the optical properties of thin silver films exhibiting surface plasmon resonance  

NASA Astrophysics Data System (ADS)

Investigation of the changes in the optical properties of thin silver (Ag) films deposited on quartz substrates by vacuum evaporation and subsequent vacuum annealing over the temperature range of 250C - 400C was done by using spectroscopic ellipsometry (SE) and UV-vis-NIR spectroscopy. The corresponding change in the surface morphology of the Ag films was studied by AFM imaging. It was observed that the annealing temperature is a key factor in determining the spectral position of surface plasmon resonance (SPR) in the films. Tuning the absorption band within UV to visible range is possible by varying the annealing temperature which may be utilized for enhancing the efficiency of solar cells, biosensors etc.

Mandal, Aparajita; Chaudhuri, Partha

2014-04-01

153

High temperature annealing effects on low energy iron implanted SiO 2  

NASA Astrophysics Data System (ADS)

15 keV Fe ions were implanted into a thermally grown silica film with a fluence of 1 10 16 at./cm 2 resulting in a near Gaussian concentration profile peaking at 8 at.% about 15 nm under the surface. High vacuum (10 -7 mbar) furnace annealing and electron beam annealing at high temperature resulted in diffusion of Fe inside the oxide film. Segregation of Fe atoms at the SiO 2 surface and SiO 2/Si interface was observed in both cases. EBA resulted in faster precipitation and lower out-diffusion of Fe. In-situ Rutherford Backscattering Spectrometry was performed during high vacuum annealing and is shown to be an appropriate method to investigate the diffusion rate. The differences observed between the methods are explained by the effect of excess electrons and ionization induced by the electron beam on the oxygen-vacancy mediated displacement mechanism and on the reduction of Fe oxides.

Kennedy, J.; Leveneur, J.; Markwitz, A.

2012-02-01

154

Recovery process of neutron-irradiated vanadium alloys in post-irradiation annealing treatment  

NASA Astrophysics Data System (ADS)

Experiments to determine the influence of post-irradiation annealing on the mechanical properties and microstructures of neutron-irradiated V-4Cr-4Ti alloys were conducted. Two groups of specimens (as-irradiated specimens and specimens which underwent the post-irradiation annealing treatment) were subjected to tensile tests at room temperature and 773 K. Post-irradiation annealing experiments carried out over periods of up to 50 h were used to restore strength and ductility. As annealing time was extended, ductility was recovered up to 5% at 50 h anneal; however irradiation hardening was not recovered completely. Microstructural changes due to post-irradiation annealing corresponded to the amount that yield stress increased in tensile behavior in the irradiated specimen. The recovery in ductility was likely caused by the dissolution of interstitial impurities from defect clusters and dislocation cores produced by neutron irradiation during post-irradiation anneal treatment. A 3% elongation recovery in V-4Cr-4Ti alloys was achieved by annealing at 773 K for 20 h in a vacuum for neutron-irradiated samples at low temperature.

Fukumoto, K.; Iwasaki, M.; Xu, Q.

2013-11-01

155

Cryogenic vacuum tight adhesive  

NASA Astrophysics Data System (ADS)

A synthetic adhesive for vacuum tight joints at cryogenic temperatures has been developed. It consists of three components, the main component being epoxy silicone organic resin. The joints made with the adhesive remain vacuum tight at liquid helium temperature, including superfluid helium. It was found possible to connect different materials with the adhesive (copper and stainless steel with each other, aluminum, aluminum alloys, fiberglass, etc.). The joints withstood thermal shock tests of ten repeated sharps cooling to liquid nitrogen temperature and heating in hot water. Using the adhesive a lot of different vacuum tight low temperature joints have been made. More than fifteen years of wide application of this adhesive in vacuum tight cryogenic joints proved its high reliability. Some designs of vacuum tight cryogenic joints are presented and the technique of their manufacturing is described.

Anashkin, O. P.; Keilin, V. E.; Patrikeev, V. M.

1999-12-01

156

Ion Implantation and Laser Annealing.  

National Technical Information Service (NTIS)

Three ion implantation and laser annealing projects have been performed by ORNL through the DOE sponsored Seed Money Program. The research has contributed toward improving the characteristics of wear, hardness, and corrosion resistance of some metals and ...

1986-01-01

157

An Automatic Electric Annealing Furnace.  

National Technical Information Service (NTIS)

A novel technique for annealing corundum crystals consists in rapidly cooling the crystals to room temperature after growth is complete, transferring them to an automatically programmed electric furnace and reheating them to 1980 deg. C, and then cooling ...

J. A. Adamski W. A. Yasinski

1968-01-01

158

Wolf-Rayet phenomena  

NASA Technical Reports Server (NTRS)

An outline is presented of what is currently known about the properties of stars showing Wolf-Rayet (W-R) phenomena, taking into account also the directions in which future work is leading. W-R spectra are found to be primarily an emission line spectrum superimposed on a 'hot' continuous spectrum. P Cygni absorption components are observed for some lines in some stars. A fact not realized when Thomas (1968) discussed W-R spectra is that a very few W-R stars have intrinsic absorption lines. On the basis of the spectroscopic observations, it could now be inferred that an optically thick stellar wind is involved. Many of the WN subtypes do contain some carbon. The WC subtypes contain little or no nitrogen. Attention is given to absolute visual magnitudes of W-R stars, the heterogeneity of W-R spectra, transition W-R spectra, mass loss rates, very luminous W-R objects, theoretical aspects of stellar structure and stellar winds, and evolutionary scenarios.

Conti, P. S.

1982-01-01

159

On Detecting Transient Phenomena  

NASA Astrophysics Data System (ADS)

Transient phenomena are interesting and potentially highly revealing of details about the processes under observation and study that could otherwise go unnoticed. It is therefore important to maximize the sensitivity of the method used to identify such events. In this article, we present a general procedure based on the use of the likelihood function for identifying transients which is particularly suited for real-time applications because it requires no grouping or pre-processing of the data. The method makes use of all the information that is available in the data throughout the statistical decision-making process, and is suitable for a wide range of applications. Here we consider those most common in astrophysics, which involve searching for transient sources, events or features in images, time series, energy spectra, and power spectra, and demonstrate the use of the method in the case of a weak X-ray flare in a time series and a short-lived quasi-periodic oscillation in a power spectrum. We derive a fit statistic that is ideal for fitting arbitrarily shaped models to a power density distribution, which is of general interest in all applications involving periodogram analysis.

Blanger, G.

2013-08-01

160

Quantum annealing with manufactured spins.  

PubMed

Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins; however, finding such a ground state remains computationally difficult. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. If it could be harnessed, quantum annealing might improve on known methods for solving certain types of problem. However, physical investigation of quantum annealing has been largely confined to microscopic spins in condensed-matter systems. Here we use quantum annealing to find the ground state of an artificial Ising spin system comprising an array of eight superconducting flux quantum bits with programmable spin-spin couplings. We observe a clear signature of quantum annealing, distinguishable from classical thermal annealing through the temperature dependence of the time at which the system dynamics freezes. Our implementation can be configured in situ to realize a wide variety of different spin networks, each of which can be monitored as it moves towards a low-energy configuration. This programmable artificial spin network bridges the gap between the theoretical study of ideal isolated spin networks and the experimental investigation of bulk magnetic samples. Moreover, with an increased number of spins, such a system may provide a practical physical means to implement a quantum algorithm, possibly allowing more-effective approaches to solving certain classes of hard combinatorial optimization problems. PMID:21562559

Johnson, M W; Amin, M H S; Gildert, S; Lanting, T; Hamze, F; Dickson, N; Harris, R; Berkley, A J; Johansson, J; Bunyk, P; Chapple, E M; Enderud, C; Hilton, J P; Karimi, K; Ladizinsky, E; Ladizinsky, N; Oh, T; Perminov, I; Rich, C; Thom, M C; Tolkacheva, E; Truncik, C J S; Uchaikin, S; Wang, J; Wilson, B; Rose, G

2011-05-12

161

Linear response theory for annealing of radiation damage in semiconductor devices  

NASA Technical Reports Server (NTRS)

A theoretical study of the radiation/annealing response of MOS ICs is described. Although many experiments have been performed in this field, no comprehensive theory dealing with radiation/annealing response has been proposed. Many attempts have been made to apply linear response theory, but no theoretical foundation has been presented. The linear response theory outlined here is capable of describing a broad area of radiation/annealing response phenomena in MOS ICs, in particular, both simultaneous irradiation and annealing, as well as short- and long-term annealing, including the case when annealing is nearing completion. For the first time, a simple procedure is devised to determine the response function from experimental radiation/annealing data. In addition, this procedure enables us to study the effect of variable temperature and dose rate, effects which are of interest in spaceflight. In the past, the shift in threshold potential due to radiation/annealing has usually been assumed to depend on one variable: the time lapse between an impulse dose and the time of observation. While such a suggestion of uniformity in time is certainly true for a broad range of radiation annealing phenomena, it may not hold for some ranges of the variables of interest (temperature, dose rate, etc.). A response function is projected which is dependent on two variables: the time of observation and the time of the impulse dose. This dependence on two variables allows us to extend the theory to the treatment of a variable dose rate. Finally, the linear theory is generalized to the case in which the response is nonlinear with impulse dose, but is proportional to some impulse function of dose. A method to determine both the impulse and response functions is presented.

Litovchenko, Vitaly

1988-01-01

162

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses  

Microsoft Academic Search

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses were investigated by an X-ray diffraction technique. It was observed that the stacking fault probability in Cu-10 Zn alloy increases as a logarithmic function of time. This phenomena is associated with the segregation of zinc atoms to stacking faults. The ther mo mechanically treated (CW at RT,

Tarik mer Ogurtani

1975-01-01

163

Effects of aluminum on the interaction of detonation diamond nanocrystals during high-temperature annealing  

NASA Astrophysics Data System (ADS)

The annealing of detonation nanodiamond particles in the presence of aluminum is accompanied by small growth of these nanoparticles and their consolidation into nanostructural metal-diamond aggregates. These phenomena are indicative of the interaction of aluminum with impurity atoms and the formation of covalent bonds between surface carbon atoms of adjacent diamond nanocrystals.

Plotnikov, V. A.; Dem'yanov, B. F.; Makarov, S. V.

2009-05-01

164

Resolving Localisation Phenomena  

NASA Astrophysics Data System (ADS)

Realistic numerical models of the Earth's crust and lithosphere require consitutive models which account for brittle/semi-brittle deformation. These are typically nonlinear, and produce localisation phenomena (e.g. faults, shear bands). The presence of a fault can cause variations in the deformation field over a length of the order of the fault / fault-zone thickness ?. Depending on the overall scale of the numerical model (global or regional), the interpretation of the fault thickness may vary, however it is typically the feature with the smallest length scale in the system. In order to accurately compute the stress and strain rate from our numerical models, we must ensure that we resolve shear bands to the point where characteristic patterns no longer change with resolution. This means using a discretisation which can resolve length scales of size ?. This is computationally difficult as the location of the shear band are not predefined. Furthermore, the length scale ? is typically several orders of magnitude smaller than the size of the domain. We have developed a numerical scheme suitable for modelling crustal/lithosphere deformation which dynamically modifies the spatial resolution in the vicinity of shear bands. The method comprises a mixed eulerian/lagrangian approach employing both finite elements and moving material points. Adaptivity at the grid and material point level is introduced using techniques from the nonlinear, adaptive finite elements. By combining standard element based error estimators and recovery techniques we can obtain continuous solutions for u_i, p and ?ij which are accurate to within a specified tolerance though out the entire domain. We show that the optimal rate of convergence is obtained for all fields and illustrate the effectiveness of the adaptive material point method via some simple localisation problems.

May, D.; Moresi, L.

2006-12-01

165

Radiation damage and annealing of amorphous silicon solar cells  

NASA Technical Reports Server (NTRS)

Amorphous silicon solar cells were irradiated with 1 MeV electrons at the Space Environmental Effects Laboratory of the NASA Langley Research Center. The cells accumulated a total fluence of 10 to the 14th, 10 to the 15th, and 10 to the 16th electrons per square centimeter and exhibited increasing degradation with each irradiation. This degradation was tracked by evaluating the I-V curves for AM0 illumination and the relative spectral response. The observed radiation damage was reversed following an anneal of the cells under vacuum at 200 C for 2 hours.

Byvik, C. E.; Slemp, W. S.; Smith, B. T.; Buoncristiani, A. M.

1984-01-01

166

Everyday Phenomena and Teachers' Training.  

ERIC Educational Resources Information Center

Investigated the ability of Swedish student teachers to explain everyday phenomena in science education, asking all fourth-term student teachers about phenomena where transformations of matter were involved. Analysis of students' written answers indicates that there is a great need in teacher training to work with conceptual understanding and with

Eskilsson, Olle; Holgersson, Ingemar

1999-01-01

167

Thermophoretic vacuum wand  

SciTech Connect

A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

Klebanoff, L.E.; Rader, D.J.

2000-06-06

168

Thermophoretic vacuum wand  

SciTech Connect

A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

Klebanoff, Leonard Elliott (San Ramon, CA); Rader, Daniel John (Lafayette, CA)

2000-01-01

169

Thermophoretic vacuum wand  

DOEpatents

A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

Klebanoff, Leonard Elliott (San Ramon, CA); Rader, Daniel John (Lafayette, CA)

2001-01-01

170

Evading death by vacuum  

NASA Astrophysics Data System (ADS)

In the Standard Model, the Higgs potential allows only one minimum at tree level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already allow to exclude many panic vacuum solutions.

Barroso, A.; Ferreira, P. M.; Ivanov, I. P.; Santos, Rui; Silva, Joo P.

2013-09-01

171

Vacuum deposition system  

SciTech Connect

The Physics Section vacuum deposition system is available for several types of thin film techniques. This vacuum evaporation system operates in the high vacuum range. The evaporation source is a resistive heating element, either a boat or a filament design. Coating is then line of sight from the source. Substrates to be coated can have a maximum diameter of 17 inches. At this time the variations in the thickness of the coatings can be controlled, by monitor, to within about 100 angstroms. The system diagrams follow the Operation Procedures and the Sample Coating Procedures provided in this document. 3 figs.

Austin, S.; Bark, D.

1990-05-31

172

Structure and magnetic properties of FePt and FePt\\/C thin films by post-annealing  

Microsoft Academic Search

FePt and FePt\\/C thin films were prepared by RF magnetron sputtering, then post-annealed in vacuum. The as-deposited films were in disordered state, and the ordered L10 structure was obtained by post-annealing at 550C for 30min. Superlattice peaks (001) and (110) can be found in the X-ray diffraction pattern of FePt and FePt\\/C films, which indicate that the FCC phase has

Xiao-Hong Xu; Hai-Shun Wu; Xiao-Li Li; Fang Wang; Jing-Fang Duan

2004-01-01

173

Atomic-scale investigation of graphene grown on Cu foil and the effects of thermal annealing.  

SciTech Connect

We have investigated the effects of thermal annealing on ex-situ chemically vapor deposited submonolayer graphene islands on polycrystalline Cu foil at the atomic-scale using ultrahigh vacuum scanning tunneling microscopy. Low-temperature annealed graphene islands on Cu foil (at 430 C) exhibit predominantly striped Moir patterns, indicating a relatively weak interaction between graphene and the underlying polycrystalline Cu foil. Rapid high-temperature annealing of the sample (at 700-800 C) gives rise to the removal of Cu oxide and the recovery of crystallographic features of the copper that surrounds the intact graphene. These experimental observations of continuous crystalline features between the underlying copper (beneath the graphene islands) and the surrounding exposed copper areas revealed by high-temperature annealing demonstrates the impenetrable nature of graphene and its potential application as a protective layer against corrosion.

Cho, J. W.; Gao, L.; Tian, J.; Cao, H.; Wu, W.; Yu, Q.; Yitamben, E. N.; Fisher, B.; Guest, J. R.; Chen, Y. P.; Guisinger, N. P. (Center for Nanoscale Materials); (Purdue Univ.); (Univ. of Houston)

2011-05-01

174

Annealing and Test Temperature Dependence of Tensile Properties of UNS N04400 Alloy  

NASA Astrophysics Data System (ADS)

Effects of annealing and test temperatures on the tensile behavior of UNS N04400 alloy have been examined. The specimens were annealed at 800, 1000, and 1200 C for 4 h under vacuum in a muffle furnace. Stress-strain curves of the specimens were obtained in the temperature range 25-300 C using a universal testing machine fitted with a thermostatic chamber. The results indicate that the yield strength (YS), ultimate tensile strength (UTS), and percentage elongation of the specimens decrease with increase of annealing temperature. By increasing the test temperature, the YS and UTS decrease, whereas the percentage elongation initially decreases with increase of test temperature from 25 to 100 C and then increases with further increasing the temperature up to 300 C. The changes in the tensile properties of the alloy are associated with the post-annealing microstructure and modes of fracture.

Afzal, Naveed; Ahmad, R.; Akhtar, Tanveer; Ayub, R.; Ghauri, I. M.

2013-07-01

175

Origin of New Broad Raman D and G Peaks in Annealed Graphene  

PubMed Central

Since graphene, a single sheet of graphite, has all of its carbon atoms on the surface, its property is very sensitive to materials contacting the surface. Herein, we report novel Raman peaks observed in annealed graphene and elucidate their chemical origins by Raman spectroscopy and atomic force microscopy (AFM). Graphene annealed in oxygen-free atmosphere revealed very broad additional Raman peaks overlapping the D, G and 2D peaks of graphene itself. Based on the topographic confirmation by AFM, the new Raman peaks were attributed to amorphous carbon formed on the surface of graphene by carbonization of environmental hydrocarbons. While the carbonaceous layers were formed for a wide range of annealing temperature and time, they could be effectively removed by prolonged annealing in vacuum. This study underlines that spectral features of graphene and presumably other 2-dimensional materials are highly vulnerable to interference by foreign materials of molecular thickness.

Hong, Jinpyo; Park, Min Kyu; Lee, Eun Jung; Lee, DaeEung; Hwang, Dong Seok; Ryu, Sunmin

2013-01-01

176

Atomic-scale investigation of graphene grown on Cu foil and the effects of thermal annealing.  

PubMed

We have investigated the effects of thermal annealing on ex-situ chemically vapor deposited submonolayer graphene islands on polycrystalline Cu foil at the atomic-scale using ultrahigh vacuum scanning tunneling microscopy. Low-temperature annealed graphene islands on Cu foil (at ?430 C) exhibit predominantly striped Moire? patterns, indicating a relatively weak interaction between graphene and the underlying polycrystalline Cu foil. Rapid high-temperature annealing of the sample (at 700-800 C) gives rise to the removal of Cu oxide and the recovery of crystallographic features of the copper that surrounds the intact graphene. These experimental observations of continuous crystalline features between the underlying copper (beneath the graphene islands) and the surrounding exposed copper areas revealed by high-temperature annealing demonstrates the impenetrable nature of graphene and its potential application as a protective layer against corrosion. PMID:21500843

Cho, Jongweon; Gao, Li; Tian, Jifa; Cao, Helin; Wu, Wei; Yu, Qingkai; Yitamben, Esmeralda N; Fisher, Brandon; Guest, Jeffrey R; Chen, Yong P; Guisinger, Nathan P

2011-05-24

177

Supermite vacuum interface design  

SciTech Connect

A new water-plastic-vacuum interface has been designed for Sandia Laboratory's Supermite (2.8 MV, 2.2 ohm) accelerator. This design was based on the PBFA I vacuum interface. Electrostatic field plots show that in positive polarity the water feed to the PBFA I interface will fail at 2 MV on Supermite. This is confirmed by positive polarity experiments and field plots using the PBFA I style vacuum interface at the Naval Research Labs. Modifications to the water section geometry to increase the water breakdown strength in positive polarity result in equivalent electric field grading at the plastic-vacuum interface but allow positive polarity operation at voltages up to 3.1 MV. This is accomplished by incorporating a dielectric field shaper which significantly improves the electric field grading across the insulator.

Moore, W.B.; Stinnett, R.W.; McDaniel, D.H.

1985-01-01

178

Multistage Turbomolecular Vacuum Pump.  

National Technical Information Service (NTIS)

The patent describes a multistage vacuum turbomolecular pump which consists of a housing containing rotor and stator disks having working elements (blades, radial slots) along their periphery. To increase the compression stage and reducing the reverse flo...

B. V. Ivanov I. D. Anokhin L. B. Leonov V. I. Kuznetsov

1973-01-01

179

Vacuum Pump Explosion Study.  

National Technical Information Service (NTIS)

An investigation was made into explosions and backfires occurring in vacuum pumps used on Navy oxygen component test stands. Research and testing uncovered several fire and toxicity hazards on these pumps which carry gaseous oxygen flows. Corrective recom...

H. H. Yuen T. D. Weikel

1972-01-01

180

On Gowdy vacuum spacetimes  

NASA Astrophysics Data System (ADS)

Using Fuchsian techniques, a large family of Gowdy vacuum spacetimes have been constructed for which one has detailed control over asymptotic behaviour. In this paper we formulate a condition on initial data yielding the same form of asymptotics.

Ringstrm, Hans

2004-03-01

181

Vacuum Camera Cooler  

NASA Technical Reports Server (NTRS)

Acquiring cheap, moving video was impossible in a vacuum environment, due to camera overheating. This overheating is brought on by the lack of cooling media in vacuum. A water-jacketed camera cooler enclosure machined and assembled from copper plate and tube has been developed. The camera cooler (see figure) is cup-shaped and cooled by circulating water or nitrogen gas through copper tubing. The camera, a store-bought "spy type," is not designed to work in a vacuum. With some modifications the unit can be thermally connected when mounted in the cup portion of the camera cooler. The thermal conductivity is provided by copper tape between parts of the camera and the cooled enclosure. During initial testing of the demonstration unit, the camera cooler kept the CPU (central processing unit) of this video camera at operating temperature. This development allowed video recording of an in-progress test, within a vacuum environment.

Laugen, Geoffrey A.

2011-01-01

182

A new model for vacuum quality and lifetime prediction in hermetic vacuum bonded MEMS  

NASA Astrophysics Data System (ADS)

In many MEMS applications the level of vacuum is a key issue as it directly affects the quality of the device, in terms of response reliability. Due to the unavoidable desorption phenomena of gaseous species from the internal surfaces, the vacuum inside a MEMS, after bonding encapsulation, tends to be degraded, unless a proper getter solution is applied. The in situ getter film (PaGeWafer) is recognised to be the most reliable way to get rid of degassed species, assuring uniform, high quality performances of the device throughout the lifetime. Moreover, post process vacuum quality control and reliability for hermetic bonding is extremely important for overall device reliability and process yield. In this paper we will discuss the main factors that are critical in the attainment of vacuum and will present a novel calculation model that enables the prediction of vacuum level after bonding, making also possible the estimate of the lifetime. Furthermore, a new analytical method based on the residual gas analyses (RGA) will be presented that gives the main characteristics of the materials. Modeling and simulation work support the process optimization and system design.

Bonucci, A.; Guadagnuolo, S.; Caterino, A.; Conte, A.; Moraja, M.

2008-03-01

183

Influence of Substrate Nature and Annealing on Electro-Optical Properties of ZnO Thin Films  

NASA Astrophysics Data System (ADS)

ZnO thin films were grown on different substrates (glass, quartz, silicon wafers, etc) by vacuum thermal evaporation. Different thermal treatments were performed in order to obtain transparent and conductive or high resistive ZnO tin films. The optical and electrical properties of ZnO thin films are dependent on the crucible temperature, annealing conditions and on the substrate nature. The thin films are transparent and have an electrical resistivity in 10-4 ?m regio. The annealing process performed in vacuum at 573K or under UV irradiation determines a decrease in the electrical resistivity of films.

Iacomi, Felicia; Baban, C.; Iftimie, Nicoleta; Prepelita, Petronela; Luca, D.

2007-04-01

184

Effect of residual solvent and thermal annealing on a light-emitting polymer-based electrochemical cell  

NASA Astrophysics Data System (ADS)

The effect of residual solvents and thermal annealing on light-emitting electrochemical cells constructed using poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] and poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (Li triflate) was investigated. The turn-on voltage dropped when the films were annealed in dry and vacuum atmospheres. This is attributed to the removal of residual solvents that are detected by mass spectrometry in ultrahigh vacuum. The results are interpreted in terms of a model in which ionized Li triflate has higher ionic conductivity in the presence of dry PEO than when solvated by water or cyclohexanone within a PEO matrix.

Zhao, Wei; White, J. M.

2007-04-01

185

Nonlinear Squeezed Vacuum States:  

NASA Astrophysics Data System (ADS)

Some of the properties of nonlinear squeezed vacuum states associated with trapped ions are considered, especially the photon number distribution, the phase properties, the Husimi-Kano Q function and the Wigner-Moyal W function of these nonlinear squeezed vacuum states. The structure of these functions is shown to depend on the nonlinearity parameter, its functional dependence and the squeezing parameter. It is shown that increasing the nonlinearity parameter results in the photon number distribution being squeezed independent.

Darwish, M.

186

Precision of Vacuum Mechanisms  

Microsoft Academic Search

The required precision of vacuum installations in most technologies (thin film coating, electron beam welding, diffusionwelding)\\u000a is the same as in traditional engineering industry, but operating conditions of the mechanisms work are much worse, because\\u000a of vacuum and periodical outgassing baking (see Tables 1.1, 1.2, 1.4). At the same time, the equipment of surface research,\\u000a electron beam-, ion beam lithography,

E. A. Deulin; V. P. Mikhailov; Yu. V. Panfilov; R. A. Nevshupa

187

Vacuum Erection Devices  

Microsoft Academic Search

Vacuum erection devices (VEDs) are safe, effective treatments for erectile dysfunction with few side effects. Vacuum negative\\u000a pressure more than 100 mmHg causes a combination of arterial and venous blood to fill the corpora cavernosum. The use of an\\u000a elastic band to trap the blood within the penis allows sufficient rigidity for penetration. Devices approved by the Food and\\u000a Drug

Hunter Wessells

188

Vacuum self-magnetization?  

SciTech Connect

We study vacuum properties in a strong magnetic field as the zero temperature and zero density limit of quantum statistics. For charged vector bosons (W bosons) the vacuum energy density diverges for B > B{sub c} = m{sub w}{sup 2}/e, leading to vacuum instability. A logarithmic divergence of vacuum magnetization is found for B = Bc, which suggests that if the magnetic field is large enough, it is self-consistently maintained, and this mechanism actually prevents B from reaching the critical value Bc. For virtual neutral vector bosons bearing an anomalous magnetic moment, the instability of the ground state for B > B{sub c}{sup '} = m{sub n}{sup 2}/q also leads to the vacuum energy density divergence for fields B > B{sub c}{sup '} and to the magnetization divergence for B B{sub c}{sup '}. The possibility of virtual electron-positron pairs bosonization in strong magnetic field and the applicability of the neutral bosons model to describe the virtual positronium behavior in a magnetic field are discussed. We conjecture that this could lead to vacuum self-magnetization in QED.

Perez Rojas, H.; Rodriguez Querts, E. [Instituto de Cibernetica, Matematica y Fisica, Calle E No. 309, esq. a 15 Vedado, C. Havana (Cuba)

2006-06-19

189

Simulated annealing for topological solitons  

NASA Astrophysics Data System (ADS)

The search for solutions of field theories allowing for topological solitons requires that we find the field configuration with the lowest energy in a given sector of topological charge. The standard approach is based on the numerical solution of the static Euler-Lagrange differential equation following from the field energy. As an alternative, we propose to use a simulated annealing algorithm to minimize the energy functional directly. We have applied simulated annealing to several nonlinear classical field theories: the sine-Gordon model in one dimension, the baby Skyrme model in two dimensions and the nuclear Skyrme model in three dimensions. We describe in detail the implementation of the simulated annealing algorithm, present our results and get independent confirmation of the studies which have used standard minimization techniques.

Hale, Mark; Schwindt, Oliver; Weidig, Tom

2000-09-01

190

Annealing effect on microstructure and mechanical properties of amorphous Al-C-N films  

NASA Astrophysics Data System (ADS)

Al-C-N thin films with different Al contents were deposited on Si (1 0 0) substrates by closed-field unbalanced reactive magnetron sputtering in the mixture of argon and nitrogen gases. These films were subsequently vacuum-annealed at 700 C and 1000 C, respectively. The microstructures of as-deposited and annealed films were characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM); while the hardness and elastic modulus values were measured by nano-indention method. The results indicated that the microstructure of both as-deposited and annealed Al-C-N films strongly depended on Al content. For thin films at low Al content, film delamination rather than crystallization occurred after the sample was annealed at 1000 C. For thin films at high Al content, annealing led to the formation of AlN nanocrystallites, which produced nanocomposites of AlN embedded into amorphous matrices. Both the density and size of AlN nanocrystallites were found to decrease with increasing depth from the film surface. With increasing of annealing temperature, both hardness and elastic modulus values were decreased; this trend was decreased at high Al content. Annealing did not change elastic recovery property of Al-C-N thin films.

Luo, Q. H.; Lu, Y. H.; Lou, Y. Z.

2011-05-01

191

PSSA: Parallel Stretched Simulated Annealing  

NASA Astrophysics Data System (ADS)

We consider the problem of finding all the global (and some local) minimizers of a given nonlinear optimization function (a class of problems also known as multi-local programming problems), using a novel approach based on Parallel Computing. The approach, named Parallel Stretched Simulated Annealing (PSSA), combines simulated annealing with stretching function technique, in a parallel execution environment. Our PSSA software allows to increase the resolution of the search domains (thus facilitating the discovery of new solutions) while keeping the search time bounded. The software was tested with a set of well known problems and some numerical results are presented.

Ribeiro, Tiago; Rufino, Jos; Pereira, Ana I.

2011-09-01

192

Annealing effect on the structural, mechanical and electrical properties of titanium-doped diamond-like carbon films  

Microsoft Academic Search

Titanium-doped diamond-like carbon (Ti-doped DLC) films with a Ti content of 1.1at.% were synthesized on a Si substrate by a process that involves filtered cathodic vacuum arc (FCVA) and metal vapor vacuum arc (MeVVA) systems. The effect of annealing temperature on the microstructure, surface roughness, hardness and electrical resistivity of the resulting films was evaluated in this study. The Raman

Yu-Hung Lin; Hong-Da Lin; Chun-Kuo Liu; Meng-Wen Huang; Ya-Chi Chen; Jiann-Ruey Chen; Han C. Shih

2009-01-01

193

Magnetic properties of iron/graphite core shell nanoparticles prepared by annealing of Fe C N-based nanocomposite  

NASA Astrophysics Data System (ADS)

We are reporting the phase composition and magnetic properties of the core-shell structured iron/graphite nanoparticles formed during annealing of a nanopowder prepared by laser pyrolysis of gas phase reactants. The originally synthesized Fe-C-N-based nanocomposite powder was characterized by TEM, XRD and magnetic measurements. The nanopowder was heated up to 800 C in vacuum. The presence of iron nanoparticles with a mean diameter of 40 nm in the annealed state of the nanopowder was proved by XRD and TEM analysis. Mssbauer spectroscopy was used for the characterization of the synthesized/annealed nanopowder to prove the qualitative change in the phase composition.

David, B.; Pizrov, N.; Schneeweiss, O.; Bezdi?ka, P.; Alexandrescu, R.; Morjan, I.; Crunteanu, A.; Voicu, I.

2005-04-01

194

Improvement of optical properties of Nd:YAG transparent ceramics by post-annealing and post hot isostatic pressing  

NASA Astrophysics Data System (ADS)

The Nd:YAG transparent ceramics were fabricated by vacuum sintering. The Nd:YAG samples were annealed at 1450 C for 20 h in air and followed by hot isostatic pressing (HIP) at 1700 C for 2 h in 200 MPa Ar and then re-annealed at 1250-1450 C for 10 h in air. The experimental results showed that the optical properties of Nd:YAG samples varied markedly with different post treatments. After air annealing at 1450 C for 20 h and HIP at 1700 C for 2 h under 200 MPa of Ar and then air re-annealing at 1250 C for 10 h, the transmittances of the samples increased from 51.2% to 77.2% (at 400 nm) and 78.4% to 83.6% (at 1064 nm), respectively. The annealing and HIP are effective post treatments to reduce oxygen vacancies and intergranular pores respectively in Nd:YAG transparent ceramics.

Zhang, Wei; Lu, Tiecheng; Ma, Benyuan; Wei, Nian; Lu, Zhongwen; Li, Feng; Guan, Yongbing; Chen, Xingtao; Liu, Wei; Qi, Lu

2013-10-01

195

Enhancement in visible luminescence from nanocomposite ZnO-SiOx thin films due to annealing  

NASA Astrophysics Data System (ADS)

The annealing induced enhancement in visible photoluminescence (PL) from nanocomposite (nc) ZnO-SiOx thin films was investigated. Nc ZnO-SiOx thin films consisting of ZnO nanocrystals in silica matrix were grown by depositing the films using radio frequency (rf) reactive co-sputtering and post-annealing them at temperatures of 350C and 500C in high vacuum and air. These films were characterized by Fourier transform infrared (FTIR), (PL) spectroscopy and UV-Vis spectrophotometry measurements. Thin films were also deposited on transmission electron microscopy (TEM) grids in almost identical conditions. The TEM measurement of the thin film deposited on TEM grid shows the formation of ZnO nanocrystals with a size distribution from 3.0 nm to 6.8 nm (+/-0.2 nm) in silica matrix. The UV-Vis spectra of the films show absorption features of ZnO and Zn2SiO4 phases in the films. The visible PL emission intensity and peak width increased in the annealed films. The results suggest increase in the number and size distribution of the ZnO nanocrystals in silica matrix due to the annealing resulting in increase in visible PL emission. The results of vacuum annealed films indicate that these films can be useful in the development of wide band visible light emitting devices using this material.

Kumar, V. V. Siva; Kanjilal, D.

2014-01-01

196

Initial stages of oxidation on single crystals of lithium hydride interaction between single crystal lithium hydride and a stainless steel, high vacuum container  

Microsoft Academic Search

Interaction between single crystals of lithium hydride (LiH) and surface contaminants found on clean stainless steel and gold plated stainless steel containers during a high vacuum, 350 anneal contributed significantly to the oxidation of the single crystal surfaces. Annealing the samples in the presence of a clean, polycrystalline LiH getter in a hydrogen reduced container significantly reduced surface oxidation. Thermal

R. F. Simandl; J. F. McLaughlin

1981-01-01

197

Stellarator helical vacuum vessel  

SciTech Connect

A design study of a stainless steel, heavy wall, helically shaped vacuum torus has been made for use in a proposed Stellarator configuration. The study concerns itself with the shape of the vacuum vessel and the division of the vessel into components that can be machined and welded together into a helical configuration. A complication in the design requires that a circular magnet coil be located at the minor toroidal axis and that this coil be embedded within the periphery of the vacuum vessel. The vacuum vessel has a minor toroidal axis diameter of 4 meters, a 68.6-cm shell diameter, and a 1.9-cm wall thickness. It twists about the minor toroidal axis twice in 360/sup 0/C. (An n value of 2). It is proposed that the unit be made of cylindrical segments with the ends of the cylinders cut at appropriate lengths and angles to form the helix. A mathematical derivation of the dimensions necessary to produce the required shapes of the segments has been made. Also, drawings of the vacuum vessel components have been produced on LANL's CTR CAD/CAM system. The procedure developed can be used for any value of n as dictated by physics requirements.

Yavornik, E.J.

1983-01-01

198

Sequence alignment using simulated annealing  

NASA Astrophysics Data System (ADS)

We apply simulated annealing to amino acid sequence alignment, a fundamental problem in bioinformatics, particularly relevant to evolution. Our goal was obtaining results comparable to those reached through dynamic programming algorithms, like the Needleman-Wunsch algorithm, as well as making a connection between physics and bioinformatics through a representative example.

Sar?yer, Ozan S.; Gven, Can

2010-08-01

199

Simulated annealing with extended neighbourhood  

Microsoft Academic Search

Simulated Annealing (SA) is a powerful stochastic search method applicable to a wide range of problems for which little prior knowledge is available. It can produce very high quality solutions for hard combinatorial optimization problems. However, the computation time required by SA is very large. Various methods have been proposed to reduce the computation time, but they mainly deal with

Xin Yao

1991-01-01

200

An Introduction to Simulated Annealing  

ERIC Educational Resources Information Center

An attempt to model the physical process of annealing lead to the development of a type of combinatorial optimization algorithm that takes on the problem of getting trapped in a local minimum. The author presents a Microsoft Excel spreadsheet that illustrates how this works.

Albright, Brian

2007-01-01

201

RAPID COMMUNICATION: Reduced noise in NbN hot-electron bolometer mixers by annealing  

NASA Astrophysics Data System (ADS)

We find that the sensitivity of heterodyne receivers based on superconducting hot-electron bolometers (HEBs) increases by 25-30% after annealing at 85 C in vacuum. The devices studied are twin-slot antenna coupled mixers with a small NbN bridge of 1 0.15 m2. We show that annealing changes the device properties as reflected in sharper resistive transitions of the complete device, apparently reducing the device-related noise. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and a bath temperature of 4.3 K.

Yang, Z. Q.; Hajenius, M.; Baselmans, J. J. A.; Gao, J. R.; Voronov, B.; Gol'tsman, G. N.

2006-04-01

202

Improving Vacuum Cleaners  

NASA Technical Reports Server (NTRS)

Under a Space Act Agreement between the Kirby company and Lewis Research Center, NASA technology was applied to a commercial vacuum cleaner product line. Kirby engineers were interested in advanced operational concepts, such as particle flow behavior and vibration, critical factors to improve vacuum cleaner performance. An evaluation of the company 1994 home care system, the Kirby G4, led to the refinement of the new G5 and future models. Under the cooperative agreement, Kirby had access to Lewis' holography equipment, which added insight into how long a vacuum cleaner fan would perform, as well as advanced computer software that can simulate the flow of air through fans. The collaboration resulted in several successes including fan blade redesign and continuing dialogue on how to improve air-flow traits in various nozzle designs.

1997-01-01

203

Annealing effect on the chemical structure of diamondlike carbon  

NASA Astrophysics Data System (ADS)

The effect of annealing in an ultrahigh vacuum on the chemical structure of diamondlike carbon (DLC) was investigated using photoelectron spectroscopy, thermal desorption spectroscopy, electrical resistivity, and micro-Raman spectroscopy measurements. The line shapes of the C 1s photoelectron spectra depended on annealing temperature. The relative intensities of four chemical components in the spectra were quantitatively evaluated: sp3 carbon with carbon-carbon bonds (C-C sp3 carbon), sp2 carbon with carbon-carbon bonds (C-C sp2 carbon), sp2 carbon with hydrogen-carbon bonds (H-C sp2 carbon), and sp3 carbon with hydrogen-carbon bonds (H-C sp3 carbon). The variation of the ratio of the components demonstrated that hydrogen in DLC is emitted to the outside in between 450 and 600 C, and the remaining DLC is graphized above 600 C. The increase in the asymmetry of the C 1s spectra and the decrease in the electrical resistivity of the DLC film with annealing temperature agree with the picture that the H-C bonds in DLC produces large free spaces in the structure, which inhibit conductive routes and lead to high electrical resistivity.

Takabayashi, Susumu; Okamoto, Keishi; Sakaue, Hiroyuki; Takahagi, Takayuki; Shimada, Kenya; Nakatani, Tatsuyuki

2008-08-01

204

Effect of Annealing Ambient on the Electrical and Optical Properties of Aluminum-Doped ZnO Films Produced via a Sol-Gel Process  

NASA Astrophysics Data System (ADS)

In this study, aluminum-doped ZnO (AZO) thin films were prepared by a sol-gel with spin coating process. The AZO films were annealed by a two-step process. The films were first annealed in air or nitrogen at 500C for 3 h, followed by annealing in three types of ambient, i.e., vacuum (10-3 Torr or 10-6 Torr) or forming gas (10% H2/90% N2), at 500C for 4 h. The effect of the annealing ambient on the microstructure, electrical and optical properties of the AZO films was explored by x-ray diffraction, field-emission scanning electron microscopy, four-point probe sheet resistivity measurements, Hall voltage measurements, and ultraviolet-visible spectroscopy. The results showed that the size of AZO particulates in the films was determined mainly by the first annealing step. The films annealed in air in the first step were composed of larger AZO particulates than those annealed in nitrogen. The conductivities of the AZO films were significantly increased by the second annealing step. Second annealing in a high-vacuum system (10-6 Torr) led to the highest AZO film conductivity among the three ambients. Regardless of the various annealing processes, the films remained transparent under visible light and exhibited a sharp absorption edge in the ultraviolet region. The highest conductivity, i.e., 168 S cm-1, was obtained from films annealed first in air and then in vacuum of 10-6 Torr.

Ho, Yung-Shou; Chen, Yi-Siou; Wu, Cheng-Heng

2014-07-01

205

Magnetic and electric properties of a quantum vacuum  

NASA Astrophysics Data System (ADS)

In this report we show that a vacuum is a nonlinear optical medium and discuss what the optical phenomena are that should exist in the framework of the standard model of particle physics. We pay special attention to the low energy limit. The predicted effects for photons of energy smaller than the electron rest mass are of such a level that none have yet been observed experimentally. Progress in field sources and related techniques seem to indicate that in a few years vacuum nonlinear optics will be accessible to human investigation.

Battesti, R.; Rizzo, C.

2013-01-01

206

Vacuum alignment in technicolor theories: The technifermion sector  

SciTech Connect

We have carried out numerical studies of vacuum alignment in technicolor models of electroweak and flavor symmetry breaking. The goal is to understand alignment implications for strong and weak CP nonconservation in quark interactions. In this first part, we restrict our attention to the technifermion sector of simple models. We find several interesting phenomena, including (1) the possibility that all observable phases in the technifermions' unitary vacuum-alignment matrix are integer multiples of {pi}/N{sup '} where N{sup '}{<=}N, the number of technifermion doublets, and (2) the possibility of exceptionally light pseudo Goldstone technipions. (c) 2000 The American Physical Society.

Lane, Kenneth [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States)] [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States); Rador, Tonguc [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States)] [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States); Eichten, Estia [Fermilab, P.O. Box 500, Batavia, Illinois 60510 (United States)] [Fermilab, P.O. Box 500, Batavia, Illinois 60510 (United States)

2000-07-01

207

Electrostatic Levitator Vacuum Chamber  

NASA Technical Reports Server (NTRS)

Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

208

Critical velocity phenomena and the LTP. [Lunar Transient Phenomena  

NASA Technical Reports Server (NTRS)

When the relative velocity between magnetized plasma and neutral gas exceeds a critical value, the gas-plasma interaction is dominated by collective phenomena which rapidly excite and ionize the neutrals. The interaction of the solar wind with a large cloud (between 10 to the 24th and 10 to the 28th power neutrals) vented from the moon should be of this type. Line radiation from such an interaction can yield an apparent lunar surface brightness rivaling reflected sunlight levels over small areas, if the kinetic-energy flow density of the gas is sufficiently high. The aberrated solar-wind flow past the moon would enhance the visibility of such interactions near the lunar sunrise terminator, supporting the statistical studies which indicate that the 'Lunar Transient Phenomena' (anomalous optical phenomena on the moon) are significantly correlated with the position of the terminator on the lunar surface.

Srnka, L. J.

1977-01-01

209

Flash Annealing for Hermetic Motor Manufacturing,  

National Technical Information Service (NTIS)

A new annealing system using the medium-frequency induction heating method has been developed for manufacturing small-motor laminated cores. In this annealing system, laminated cores are moved continuously through a solenoid heating coil by a conveyer. By...

M. Hirao A. Maegawa M. Wada

1987-01-01

210

No energy to be extracted from the vacuum  

NASA Astrophysics Data System (ADS)

A few years ago a hopeful article (Evans 2000 Phys. Scr.61 513-7) appeared in this journal promising that according to its 15 authors' opinion the pending energy crisis could be solved by 'extracting energy from the vacuum'. However, in the past years the energy price has grown to unthinkable heights: a reason for having a look at the promised 'energy from the vacuum' in (Evans 2000). So we shall do so below and shall arrive at a great disappointment: the 15 authors were in error; their vacuum energy stems from a simple flaw of thinking by misinterpreting the well-known Lorenz term of the classical Maxwell gauge theory. Their miraculous conclusion should have made the authors suspicious, that just the Lorenz term should yield a vacuum current. Surely, its a pity that vacuum currents and vacuum energy in (Evans 2000) have their origin merely in a simple flaw of thinking, and all further speculations for a vacuum energy density are in vain. However, better to return to reality. Quote: Abstract of [1]: Great announcements... It is shown that if the Loren(t)z condition is discarded, the Maxwell-Heaviside field equations become the Lehnert equations, indicating the presence of charge density and current density in the vacuum. The Lehnert equations are a subset of the O(3) Yang-Mills field equations. Charge and current density in the vacuum are defined straightforwardly in terms of the vector potential and scalar potential, and are conceptually similar to Maxwell's displacement current, which also occurs in the classical vacuum. A demonstration is made of the existence of a time dependent classical vacuum polarization which appears if the Loren(t)z condition is discarded. Vacuum charge and current appear phenomenologically in the Lehnert equations but fundamentally in the O(3) Yang-Mills theory of classical electrodynamics. The latter also allows for the possibility of the existence of vacuum topological magnetic charge density and topological magnetic current density. Both O(3) and Lehnert equations are superior to the Maxwell-Heaviside equations in being able to describe phenomena not amenable to the latter. In theory, devices can be made to extract the energy associated with vacuum charge and current. A review of a former article in this journal.

Bruhn, Gerhard W.

2006-11-01

211

Effects of Post Dielectric Deposition and Post Metallization Annealing Processes on Metal/Dy2O3/Si(100) Diode Characteristics  

NASA Astrophysics Data System (ADS)

Ultra-high vacuum annealing was investigated for Dy2O3 films deposited on Si(100) substrates. The leakage current of the Dy2O3 films deposited at room temperature (RT) was found to be decreased without any increase of the equivalent oxide thickness (EOT) by the in-situ vacuum annealing method compared to that of the conventional rapid thermal annealing (RTA) in O2. The negative flat-band voltage (VFB) shift observed after the in-situ vacuum annealing process was suppressed by increasing the deposition temperature of Dy2O3 on chemically oxidized Si from RT to 250C. The EOT of 1.1 nm with the leakage current of 0.29 A/cm2 (@VFB+1 V) was obtained for the Dy2O3 film after the air-brake and vacuum annealing, and the EOT of 0.63 nm with 4 A/cm2 (@VFB+1 V) was achieved for the Dy2O3 film with the TaN gate electrode after the post metallization annealing (PMA).

Ohmi, Shun-ichiro; Yamamoto, Hiroyuki; Taguchi, Junichi; Tsutsui, Kazuo; Iwai, Hiroshi

2004-04-01

212

Hybrid Quantum Annealing for Clustering Problems  

NASA Astrophysics Data System (ADS)

We develop a hybrid type of quantum annealing in which we control temperature and quantum field simultaneously. We study the efficiency of proposed quantum annealing and find a good schedule of changing thermal fluctuation and quantum fluctuation. In this paper, we focus on clustering problems which are important topics in information science and engineering. We obtain the better solution of the clustering problem than the standard simulated annealing by proposed quantum annealing.

Tanaka, Shu; Tamura, Ryo; Sato, Issei; Kurihara, Kenichi

2013-09-01

213

Nd-Fe-B thick film magnets with Nb additive prepared by vacuum arc deposition method  

NASA Astrophysics Data System (ADS)

Isotropic Nd-Fe-B thick film magnets were prepared by a vacuum arc deposition method with the deposition rate of approximately 10 ?m/h followed by pulse-annealing process. It was found that an optimum amount of Nb additive is effective to enhance the coercivity without the deterioration of remanence and (BH)max values of the isotropic thick films.

Nakano, M.; Sahara, M.; Yanai, T.; Yamashita, F.; Fukunaga, H.

2011-04-01

214

Vacuum tool manipulator.  

National Technical Information Service (NTIS)

This invention is comprised of an apparatus for manipulating a vacuum hose in a reactor vessel comprising a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing t...

W. T. Zollinger

1992-01-01

215

Vacuum insulating panel  

Microsoft Academic Search

Theoretical aspects and practical possibilities for realization of a new type of thermal insulation, vacuum panel insulation (VPI), are given. From a functional point of view, it is a flat all metal Dewar flask with an array of supporting beads. They span metal foils at desired distances and limit conduction by internal, near-point contacts. Model studies and first reports show

V Nemani?

1995-01-01

216

Vacuum thermal insulation panel  

Microsoft Academic Search

A vacuum thermal insulation panel comprises a pair of laminated plastic and aluminum sheets together with a plastic edge strip sealed to the edges of the sheets so as to define an evacuable volume in which a glass fiber mat is disposed. The insulation panel of the present invention takes advantage of the light-weight, low cost and low thermal conductivity

J. R. Young; R. M. Schreck

1984-01-01

217

Compact vacuum insulation  

Microsoft Academic Search

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass

D. K. Benson; T. F. Potter

1992-01-01

218

Compact vacuum insulation  

Microsoft Academic Search

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads

David K. Benson; Thomas F. Potter

1992-01-01

219

Topics in vacuum decay  

NASA Astrophysics Data System (ADS)

If a theory has more than one classically stable vacuum, quantum tunneling and thermal jumps make the transition between the vacua possible. The transition happens through a first order phase transition started by nucleation of a bubble of the new vacuum. The outward pressure of the truer vacuum makes the bubble expand and consequently eat away more of the old phase. In the presence of gravity this phenomenon gets more complicated and meanwhile more interesting. It can potentially have important cosmological consequences. Some aspects of this decay are studied in this thesis. Solutions with different symmetry than the generically used O(4) symmetry are studied and their actions calculated. Vacuum decay in a spatial vector field is studied and novel features like kinky domain walls are presented. The question of stability of vacua in a landscape of potentials is studied and the possible instability in large dimension of fields is shown. Finally a compactification of the Einstein-Maxwell theory is studied which can be a good lab to understand the decay rates in compactification models of arbitrary dimensions.

Masoumi, Ali

220

High Vacuum Valve.  

National Technical Information Service (NTIS)

The metal-to-metal seal vacuum valve is provided with a bellows which aids in preventing leakage through the housing cover and about the stem. The inner surface of the valve housing is provided with a metal valve seat having a relatively sharp edge around...

J. M. Frame

1965-01-01

221

Inexpensive high vacuum feedthroughs.  

NASA Technical Reports Server (NTRS)

Description of the use of rigid coaxial cable in the construction of high vacuum coaxial and coaxial push-pull rotary motion feedthroughs. This type of feedthroughs is shown to be extremely cheap and simple to make and modify. It can be used for moderately high voltages and provides a continuous, well shielded, low-noise feedthrough cable in any desired configuration.

Gerber, S.; Post, D.

1973-01-01

222

Operating a vacuum system  

Microsoft Academic Search

This discussion of vacuum gas gathering systems refers to the operation of a gathering system below atmospheric pressure. Advantages include recovery of gas that would otherwise remain in the reservoir, increased GPM content of the gathered gas, harmlessness of leaks, possibility of installing lower-priced pipe, and ability to make temporary repair of leaks. Disadvantages include difficulty of detecting leaks, severe

Felts

1981-01-01

223

Vacuum System at IUAC  

NASA Astrophysics Data System (ADS)

Vacuum technology is an integral part of any accelerator system. At IUAC we have a 15UD PELLETRON, superconduting LINAC, Low Energy Ion beam Facility and a 1.7MV pelletron. Vacuum requirement in these accelerators is ~10-8 torr. Various types of Vacuum pump are used in different zones of the accelerators depending on load. Since the whole accelerator is quite long, distributed pumps are placed in different sections as per load. In ion sources displacement type pump viz turbo-pumps are usually used as the gas load is quite high. In other parts of the accelerator combination of getter and ion pumps are used. It is very much necessary to isolate different sections for maintenance purpose. Proper valves are used to isolate the sections and to avoid vacuum accidents proper interlock system is introduced. If air goes in some sections accidentally, valves will close automatically to protect other sections. The talk will cover different types of pumps and interlock used in accelerators at IUAC.

Mandal, A.

2012-11-01

224

VACUUM FLOW STEEL DEGASSING  

Microsoft Academic Search

A steel degassing technique developed and used by the Henrichschutte ; steel plant in Germany's Ehr is described. The process, reportedly capable of ; reduci H, N, and O contents of all types of steels to those ; levels obtalned by vacuum casting techniques, require from 12 to 15 min in a 6O ; to 80-ton ladle. The metal i

Starratt

1958-01-01

225

HYDC Vacuum Circuit Breakers  

Microsoft Academic Search

The effectiveness of the commutation principle, using vacuum interrupters as a means for interrupting high direct current at high voltage, has been demonstrated convincingly by a large number of tests. Currents in excess of 15 kA at 20 kV have been interrupted by a single device in an inductive circuit. Tests are reported in which higher current were cleared by

A. N. Greenwood; P. Barkan; W. C. Kracht

1972-01-01

226

Vacuum ultraviolet holography  

NASA Technical Reports Server (NTRS)

The authors report the first demonstration of holographic techniques in the vacuum ultraviolet spectral region. Holograms were produced with coherent 1182 A radiation. The holograms were recorded in polymethyl methacrylate and read out with an electron microscope. A holographic grating with a fringe spacing of 836 A was produced and far-field Fraunhofer holograms of sub-micron particles were recorded.

Bjorklund, G. C.; Harris, S. E.; Young, J. F.

1974-01-01

227

Various unique vacuum holders  

SciTech Connect

Glassblowers use vacuum holding devices to support a flat plate in the glassflowing lathe to seal onto the end of, or inside of, a glass cylinder. Glassblowing blowhose swivels tend to leak; a rotating union from the hydraulics industry is better. Various graphite holder designs are described.

Gregar, J.S.

1992-12-01

228

Abnormal pressures as hydrodynamic phenomena  

USGS Publications Warehouse

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Neuzil, C. E.

1995-01-01

229

Demonstrations with a Vacuum: Old Demonstrations for New Vacuum Pumps.  

ERIC Educational Resources Information Center

Explains mechanisms of 19th-century vacuum pumps. Describes demonstrations using the pump including guinea and feather tube, aurora tube, electric egg, Gassiots cascade, air mill, bell in vacuum, density and buoyancy of air, fountain in vacuum, mercury shower, palm and bladder glasses, Bacchus demonstration, pneumatic man-lifter, and Magdeburg

Greenslade, Thomas B., Jr.

1989-01-01

230

Influence of annealing on tunnelling magnetoresistance of perpendicular magnetic tunnel junctions  

NASA Astrophysics Data System (ADS)

We have shown for the first time that the magnetometry on the free layer of fully perpendicular magnetic tunnel junctions (pMTJ) can be used to optimize the annealing conditions, and, subsequently, the transport properties of these devices. pMTJ stacks with Co/Pd multilayer (ML) synthetic antiferromagnet (SAF)-based pinned layer and thin Co31.5Fe58.5B10 free layer were patterned into devices and then rapid thermally annealed (RTA) in high vacuum at temperatures ranging from 350 to 500 C. The soaking time at these RTA temperatures ranged from 3 to 12 min. Under annealing condition of 500 C for 8 min yielded a tunnelling magnetoresistance (TMR) of 50% at a transport measurement temperature of 300 K and 59% at 4.2 K. Further increase in annealing time to 12 min degraded the TMR at all temperatures tested. Analysis of the minor M-H loops of the free layer of these devices showed a clear transition from partially perpendicular to fully perpendicular to in-plane anisotropy as the annealing time was increased at each temperature. These minor loops correlate strongly with the transport measurements, indicating that the optimization of perpendicular magnetic anisotropy of the free layer by annealing leads to optimized TMR as well.

Natarajarathinam, A.; Clark, B. D.; Singh, A.; Gupta, S.

2013-03-01

231

Gas bearing operates in vacuum  

NASA Technical Reports Server (NTRS)

Bearing has restrictions to reduce air leaks and is connected to external pumpout facility which removes exhausted air. Token amount of air which is lost to vacuum is easily removed by conventional vacuum pump.

Perkins, G. S.

1975-01-01

232

Furnace brazing under partial vacuum  

NASA Technical Reports Server (NTRS)

Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

Mckown, R. D.

1979-01-01

233

A radiation hard vacuum switch  

DOEpatents

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

Boettcher, G.E.

1988-07-19

234

Understand vacuum-system fundamentals  

Microsoft Academic Search

Crude vacuum unit heavy vacuum gas-oil (HVGO) yield is significantly impacted by ejector-system performance, especially at conditions below 20 mmHg absolute pressure. A deepcut vacuum unit, to reliably meet the yields, calls for proper design of all the major pieces of equipment. Ejector-system performance at deepcut vacuum column pressures may be independently or concurrently affected by: atmospheric column overflash, stripper

G. R. Martin; J. R. Lines; S. W. Golden

1994-01-01

235

Luminescence Phenomena in Magnesium Oxide.  

National Technical Information Service (NTIS)

Both intrinsic and impurity centers contribute to x-ray fluorescence and thermoluminescence phenomena in magnesium oxide. It was shown earlier that a thermoluminescent formation of Cr(2+) from Cr(3+) is accompanied by a conversion of Fe(1+) to Fe(2+) and ...

J. E. Wertz L. C. Hall J. Helgeson C. C. Chao W. S. Dykoski

1967-01-01

236

Virtual Physics Laboratory: Wave Phenomena  

NSDL National Science Digital Library

This site from Northwestern University discusses wave phenomena. The site features interactive applets of various wave types, including longitudinal, transverse, mixed, and sound waves. Also included are animations of superposition, beat frequencies, and the distinction between phase and group velocities, wave packets, and wave reflections.

Astronomy, The D.; University, Northwestern

237

Optical Phenomena in the Aether  

Microsoft Academic Search

Although the theory of light seems completed and many believe that the behavior of light has been accounted for down to the most insignificant detail, there are certain experimental facts in optics for which explanations are still unsatisfactory. It may seem surprising - but nevertheless true - if we state that in fact the most basic phenomena of reflection and

Ionel DINU

238

Quantum Phenomena Observed Using Electrons  

SciTech Connect

Electron phase microscopy based on the Aharonov-Bohm (AB) effect principle has been used to illuminate fundamental phenomena concerning magnetism and superconductivity by visualizing quantitative magnetic lines of force. This paper deals with confirmation experiments on the AB effect, the magnetization process of tiny magnetic heads for perpendicular recording, and vortex behaviors in high-Tc superconductors.

Tonomura, Akira [Okinawa Institute of Science and Technology, Onna-son, Okinawa 904-0412 (Japan); Advanced Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama, 350-0395 (Japan); Advanced Science Institute, RIKEN, Wako, Saitama, 351-0198 (Japan)

2011-05-06

239

Ultra shallow junction formation using excimer laser annealing for ultra small devices  

Microsoft Academic Search

In this paper, novel device structures in order to realize ultra fast and ultra small silicon devices are investigated using ultra-high vacuum chemical vapor deposition (UHVCVD) and excimer laser annealing (ELA). Based on these fundamental technologies for the deep sub-micron device, high speed and low power devices can be fabricated. These junction formation technologies based on damage-free process for replacing

Eun Sik Jung; Ji Chel Bea; Yong Jae Lee

2001-01-01

240

Secondary Electron Emission of Annealed Graphitic Amorphous Carbon: the Role of Evolving BANDGAP  

Microsoft Academic Search

The magnitude of secondary electron (SE) yield was found to be directly related to the size of the bandgap in this disordered carbon system. Specifically, graphitic amorphous carbon (g-C) samples were produced by vacuum annealing g-C from 0 C-1050 C, with the bandgap decreasing from 0.6 eV to 0.1 eV. We found a monotonic decrease in maximum SE yield with

Jody Corbridge; J. R. Dennison; Neal Nickles

2004-01-01

241

Investigation of interface electronic structure of annealed Ti\\/Ni multilayers  

Microsoft Academic Search

The present paper deals with a systemic investigation of the interface electronic structure of as-deposited as well as annealed Ti\\/Ni multilayer (ML) samples up to 400 C using core level and valence band (VB) photoemission techniques. For this purpose [Ti(50 )\\/Ni(50 )] 10 ML samples have been prepared by employing an electron beam evaporation technique under ultrahigh vacuum conditions.

Pramod Bhatt; S. M. Chaudhari

2005-01-01

242

Surge-damping vacuum valve  

DOEpatents

A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

Bullock, Jack C. (Pleasanton, CA) [Pleasanton, CA; Kelly, Benjamin E. (Tracy, CA) [Tracy, CA

1980-01-01

243

Perfluoropolyethers as Vacuum Pump Fluids  

ERIC Educational Resources Information Center

Discusses the state of the art in the field of utilizing perfluoropolyethers in the creation of "clean" vacuums, when the term "clean" vacuum defines one that does not contain contaminates which interfere with the process to be carried out in the vacuum. (SL)

Laurenson, L.

1977-01-01

244

Portable vacuum object handling device  

DOEpatents

The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuable to apply the vacuum to lift the object.

Anderson, G.H.

1981-07-30

245

Insertion device vacuum system designs  

SciTech Connect

Synchrotron light source insertion device vacuum systems now in operation and systems proposed for the future are reviewed. An overview of insertion devices is given and four generic vacuum chamber designs, transition section design and pumping considerations are discussed. Examples of vacuum chamber systems are presented.

Hoyer, E.

1988-05-01

246

RFQ Vacuum brazing at CERN  

Microsoft Academic Search

The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The

S Mathot

2008-01-01

247

Recursive Branching Simulated Annealing Algorithm  

NASA Technical Reports Server (NTRS)

This innovation is a variation of a simulated-annealing optimization algorithm that uses a recursive-branching structure to parallelize the search of a parameter space for the globally optimal solution to an objective. The algorithm has been demonstrated to be more effective at searching a parameter space than traditional simulated-annealing methods for a particular problem of interest, and it can readily be applied to a wide variety of optimization problems, including those with a parameter space having both discrete-value parameters (combinatorial) and continuous-variable parameters. It can take the place of a conventional simulated- annealing, Monte-Carlo, or random- walk algorithm. In a conventional simulated-annealing (SA) algorithm, a starting configuration is randomly selected within the parameter space. The algorithm randomly selects another configuration from the parameter space and evaluates the objective function for that configuration. If the objective function value is better than the previous value, the new configuration is adopted as the new point of interest in the parameter space. If the objective function value is worse than the previous value, the new configuration may be adopted, with a probability determined by a temperature parameter, used in analogy to annealing in metals. As the optimization continues, the region of the parameter space from which new configurations can be selected shrinks, and in conjunction with lowering the annealing temperature (and thus lowering the probability for adopting configurations in parameter space with worse objective functions), the algorithm can converge on the globally optimal configuration. The Recursive Branching Simulated Annealing (RBSA) algorithm shares some features with the SA algorithm, notably including the basic principles that a starting configuration is randomly selected from within the parameter space, the algorithm tests other configurations with the goal of finding the globally optimal solution, and the region from which new configurations can be selected shrinks as the search continues. The key difference between these algorithms is that in the SA algorithm, a single path, or trajectory, is taken in parameter space, from the starting point to the globally optimal solution, while in the RBSA algorithm, many trajectories are taken; by exploring multiple regions of the parameter space simultaneously, the algorithm has been shown to converge on the globally optimal solution about an order of magnitude faster than when using conventional algorithms. Novel features of the RBSA algorithm include: 1. More efficient searching of the parameter space due to the branching structure, in which multiple random configurations are generated and multiple promising regions of the parameter space are explored; 2. The implementation of a trust region for each parameter in the parameter space, which provides a natural way of enforcing upper- and lower-bound constraints on the parameters; and 3. The optional use of a constrained gradient- search optimization, performed on the continuous variables around each branch s configuration in parameter space to improve search efficiency by allowing for fast fine-tuning of the continuous variables within the trust region at that configuration point.

Bolcar, Matthew; Smith, J. Scott; Aronstein, David

2012-01-01

248

Effects of annealing and temperature on acoustic dissipation in a micromechanical silicon oscillator  

SciTech Connect

The temperature dependence (15-320 K) of the acoustic dissipation was studied for some lower vibrational modes of a suspended silicon plate 1.5 {mu}m thick. Our oscillator was exposed to the laboratory environment prior to measurement, laser annealed while in a cryogenic vacuum, and remeasured. We find a dissipation peak at 160 K, similar to results by others, and a second dissipation peak near 30 K. Annealing reduced the dissipation at 160 K by as much as a factor of 10, and gave quality factors as high as 1.4x10{sup 6} at 470 kHz and our lowest temperature. Our data support the idea that the 160 K peak is related to adsorbates, and show this mechanism is important at room temperature. Post-anneal room-temperature dissipation appears to be limited by thermoelastic loss for certain modes.

Haucke, Hans; Liu Xiao; Vignola, J.F.; Houston, B.H.; Marcus, M.H.; Baldwin, J.W. [Naval Research Laboratory, Washington DC 20375 (United States)

2005-05-02

249

Exoelectron emission from a clean, annealed magnesium single crystal during oxygen adsorption  

NASA Technical Reports Server (NTRS)

Exoelectron emission has been observed from a clean, annealed Mg (0001) surface during oxygen and chlorine adsorption at pressures of 0.000065 N/sq m and lower. The studies were performed in an ultrahigh vacuum system. The crystals were cleaned by argon-ion bombardment and annealed at 300 C. Auger electron spectroscopy was used to verify surface cleanliness, and low-energy electron diffraction was used to verify that the surface was annealed. The emission was found to be dependent on oxygen arrival rate. Two peaks were observed in the electron emission with exposure. Evidence is presented that the formation of the second peak corresponds to oxidation of the Mg surface. The results verify that electron emission occurs from a strain-free surface simply upon adsorption of oxygen. A qualitative explanation for the mechanisms of emission in terms of chemical effects is presented.

Ferrante, J.

1976-01-01

250

Edison's vacuum technology patents  

NASA Astrophysics Data System (ADS)

During 1879 Thomas Edison's Menlo Park, New Jersey laboratory developed the means to evacuate glass lamp globes to less than a mTorr in 20 min and in mid-1880 began production of carbon-filament incandescent lamps. Among Edison's nearly 1100 U.S. patents are five for vacuum pump improvements, and at least eight others that are vacuum-related; all applied for between 1880 and 1886. Inspired by an 1878 article by De La Rue and Mller [Philos. Trans. R. Soc. London, Ser. A 169, 155 (1878)] on studies of glow discharges, Edison devised a combination pump using the Geissler pump as a rough pump and the Sprengel pump for continuous exhaustion. Edison's patents described means to control the mercury flow and automate the delivery of the mercury to banks of up to a hundred pumps. Other patents described various means to remove residual gases during lamp processing.

Waits, Robert K.

2003-07-01

251

Electrostatic Levitator Vacuum Chambers  

NASA Technical Reports Server (NTRS)

Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

252

Electrostatic Levitator Vacuum Chamber  

NASA Technical Reports Server (NTRS)

Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

253

Integrated structure vacuum tube  

NASA Technical Reports Server (NTRS)

High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

Dimeff, J.; Kerwin, W. J. (inventors)

1976-01-01

254

Vacuum tool manipulator  

DOEpatents

Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm. 6 figures.

Zollinger, W.T.

1993-11-23

255

Vacuum tool manipulator  

DOEpatents

Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm.

Zollinger, William T. (3927 Almon Dr., Martinez, GA 30907)

1993-01-01

256

Compact vacuum insulation  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, D.K.; Potter, T.F.

1993-01-05

257

Compact vacuum insulation embodiments  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

Benson, D.K.; Potter, T.F.

1992-04-28

258

The MEA vacuum system  

NASA Astrophysics Data System (ADS)

The leak security system and multiple pump unit with turbomolecular pump of the MEA vacuum system, consisting of a klystron system with diode pump and a bunch-conducting system with triode pump, is described. The triode pump has better pump capacities for rare gases but as it only works from 0.0001 Torr the pump unit has to be used. To replace the klystrons the two systems are coupled by two windows with nitrogen in between for high frequencies. To safeguard the system, slow isolation valves with Pirami gages, fast valves with ionization gages, and residual gas analyzers are installed. Hand valves and residual gas analyzer heads are used for the pump unit. The vacuum level is better than 0.0000001 Torr.

Stroo, R.; Schwebeke, H.; Heine, E.

1984-12-01

259

Aspects of vacuum alignment  

NASA Astrophysics Data System (ADS)

In the presence of both spontaneous symmetry breaking and explicit symmetry breaking, the ground state of a system is determined by vacuum alignment. In this thesis I examine the consequences of vacuum alignment in models with many competing explicit symmetry breaking interactions. In particular, I investigate the appearance of unexpectedly massless pseudo-Goldstone bosons and their connection to second order phase transitions in the symmetry of the ground state. The foundation for this investigation is a model based on the spontaneous symmetry breaking pattern SU(3)L ? SU(3)R ? SU(3). One feature of this model, repeated phase transitions, motivates a new approach toward generating light states. In this approach, states are light because there are many nearby phase transitions rather than as a consequence of a symmetry. I test this new approach by applying repeated phase transitions to composite higgs models of electroweak symmetry breaking. This investigation not only elucidates the advantages and disadvantages of repeated phase transitions but it also provides a new path to a light composite higgs. A more familiar approach to a light composite higgs is the Little Higgs mechanism. This achieves a light higgs by protecting it with additional global symmetries. As a consequence of these additional symmetries, new TeV scale particles must be introduced which tend to cause conflicts with precise low energy experiments. Imposing a discrete symmetry known as T parity on these models not only removes many problematic processes but also creates a dark matter candidate. I construct a T parity invariant version of the Simplest Little Higgs model and find a cosmologically viable dark matter candidate. To demonstrate an application of vacuum alignment outside of electroweak symmetry breaking, I also examine the constraints from B meson mixings and decays on models of spontaneous CP violation in topcolor-assisted technicolor. In these models, CP is violated as a consequence of vacuum alignment in the technicolor sector, then communicated to the standard model fields through quark mass terms.

Martin, Adam O.

260

Vacuum Beat Wave Acceleration  

Microsoft Academic Search

The Vacuum Beat Wave Accelerator (VBWA) utilizes two laser beams with differing wavelengths to accelerate particles in vacuo.(Sprangle et al., Opt. Comm. 124), 69 (1996); Esarey et al., Phys. Rev. E 52, 5443 (1995). The mechanism relies on the vB force, circumventing the so-called Lawson-Woodward theorem. A proof-of-principle experiment will be performed at the Naval Research Laboratory, based on design

C. I. Moore; B. Hafizi; E. Esarey; P. Sprangle; A. Ganguly; J. L. Hirshfield

1997-01-01

261

Molecular dynamics investigation of deposition and annealing behaviors of Cu atoms onto Cu(0 0 1) substrate  

NASA Astrophysics Data System (ADS)

The deposition growth and annealing behaviors of Cu atoms onto Cu(0 0 1) are investigated in atomic scale by molecular dynamics (MD) simulation. The results indicate that the film grows approximately in a layer-island mode as the incident energy is from 1 to 5 eV, while surface intermixing can be significantly observed at 10 eV. The surface roughness of the film decreases with increasing the incident energy, and the film after annealing becomes smoother and more ordered. These phenomena may be attributed to the enhanced atomic mobility for higher incident energy and thermal annealing. It also indicates that atomic mixing is more significant with increasing both the incident energy and substrate temperature. In addition, the peak-to-peak distances of radial distribution function (RDF) clearly indicate that the films before and after annealing are still fcc structure except for that at the melting temperature of 1375.6 K. After annealing, the film at the melting temperature returns to fcc structure instead of amorphous. Moreover, the residual stress and Poisson ratio of the film are remarkably affected by the thermal annealing. Furthermore, the density of thin film is obviously affected by the substrate temperature and annealing process. Therefore, one can conclude that high incident energy, substrate temperature and thermal annealing could help to enhance the surface morphology and promote the microstructure of the film.

Jing, Xing-bin; Liu, Zu-li; Yao, Kai-lun

2012-01-01

262

Evaluation of the physical annealing strategy for simulated annealing: A function-based analysis in the landscape paradigm  

NASA Astrophysics Data System (ADS)

The effectiveness of the actual annealing strategy in finite-time optimization by simulated annealing (SA) is analyzed by focusing on the search function of the relaxation dynamics observed in the multimodal landscape of the cost function. The rate-cycling experiment, which was introduced in the previous study [M. Hasegawa, Phys. Rev. EPLEEE81063-651X 10.1103/PhysRevE.83.036708 83, 036708 (2011)] to examine the role of the relaxation dynamics in optimization, and the temperature-cycling experiment, which was developed for a laboratory experiment on relaxation-related phenomena, are conducted on two types of random traveling salesman problems (TSPs). In each experiment, the SA search starting from a quenched solution is performed systematically under a nonmonotonic temperature control used in the actual heat treatment of metals and glasses. The results show that, as in the previous monotonic cooling from a random solution, the optimizing ability is enhanced by allocating a lot of time to the search performed near an effective intermediate temperature irrespective of the annealing technique. In this productive phase, the relaxation dynamics successfully function as an optimizer and the relevant characteristics analogous to the stabilization phenomenon and the acceleration of relaxation, which are observed in glass-forming materials, play favorable roles in the present optimization. This nonmonotonic approach also has the advantage of a wider operation range of the effective relaxation dynamics, and in conclusion, the actual annealing strategy is useful and more workable than the conventional slow-cooling strategy, at least for the present TSPs. Further discussion is given of an illuminating aspect of computational physics analysis in the optimization algorithm research.

Hasegawa, M.

2012-05-01

263

The ITER vacuum systems  

NASA Astrophysics Data System (ADS)

ITER is a large vacuum facility which comprises many service, diagnostic and monitoring vacuum sub-systems as well as three large cryogenic pumping systems for evacuation and maintenance of the required pressure levels. Control of the gas throughput is one of the key issues affecting the performance and achievable burn time of a fusion reactor. The main pumping systems are the torus exhaust pumping, the cryopumps for the neutral beam injection systems for plasma heating, and the cryopumps for the ITER cryostat. All customized cryosorption pumps are force-cooled with supercritical helium and share a similar modular design of cryosorption pumping panels. For regeneration of the cryopumps as well as for roughing down the system volumes prior to operation, four identical sets of forepump trains are used. This paper will focus on the areas of the ITER vacuum systems which require customized developments and cannot rely on commercial solutions. The complex pumps have been tailored for the very specific applications and requirements at ITER, especially characterised by the need to be tritium compatible. An outline of the development path which was needed to come up with a sound design for the ITER cryopumps is given. The way of development is culminating in the manufacturing of 1:1 scale prototypes, which will be extensively tested in dedicated test facilities to ensure compatibility with all design requirements.

Day, C.; Murdoch, D.

2008-05-01

264

Highest transmittance and high-mobility amorphous indium gallium zinc oxide films on flexible substrate by room-temperature deposition and post-deposition anneals  

SciTech Connect

Amorphous indium gallium zinc oxide (a-IGZO) thin films of the highest transmittance reported in literature were initially deposited onto flexible polymer substrates at room temperature. The films were annealed in vacuum, air, and oxygen to enhance their electrical and optical performances. Electrical and optical characterizations were done before and after anneals. A partial reversal of the degradation in electrical properties upon annealing in oxygen was achieved by subjecting the films to subsequent vacuum anneals. A model was developed based on film texture and structural defects which showed close agreement between the measured and calculated carrier mobility values at low carrier concentrations (2-6 x 10{sup 19} cm{sup -3}).

Gadre, Mandar J. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Alford, T. L. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Flexible Display Center at Arizona State University, Tempe, Arizona 85284 (United States)

2011-08-01

265

Vacuum: From Art to Exact Science.  

ERIC Educational Resources Information Center

Reviews the history of vacuum technology. Includes vacuum pump developments (mechanical, ion, and cyrogenic pumps), measurement techniques, the development of the American Vacuum Society, and electronics in vacuum technology. (JN)

Lafferty, James M.

1981-01-01

266

Disorder in quantum vacuum: Casimir-induced localization of matter waves.  

PubMed

Disordered geometrical boundaries such as rough surfaces induce important modifications to the mode spectrum of the electromagnetic quantum vacuum. In analogy to Anderson localization of waves induced by a random potential, here we show that the Casimir-Polder interaction between a cold atomic sample and a rough surface also produces localization phenomena. These effects, that represent a macroscopic manifestation of disorder in quantum vacuum, should be observable with Bose-Einstein condensates expanding in proximity of rough surfaces. PMID:21231273

Moreno, G A; Messina, R; Dalvit, D A R; Lambrecht, A; Maia Neto, P A; Reynaud, S

2010-11-19

267

Texture and Microstructure Evolution at the Metal-Vapour Interface During Transformation Annealing in a Mn and Al Alloyed Ultra Low Carbon Steel  

Microsoft Academic Search

This paper investigates the evolution of texture and microstructure at the metal-vapour interface during transformation annealing\\u000a in vacuum. Interrupted annealing experiments were carried out on cold rolled Mn, Al and Si alloyed ultra low carbon steels.\\u000a The textures were characterized by X-ray diffraction and SEMEBSD techniques. The results show the variation in the surface\\u000a texture components obtained after BCC recrystallisation

Leo A. I. Kestens; Jai Gautam; Roumen Petrov

2009-01-01

268

Exchange-diffusion reactions in HfSiON during annealing studied by Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling  

Microsoft Academic Search

HfSiON films deposited on Si (001) by reactive sputtering were submitted to rapid thermal annealing at 1000 C in vacuum, N2 and O2 atmospheres. The stability of the dielectric was evaluated by measuring the atomic transport and exchange of the chemical species, using Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling. Annealing in O2 ambient reduced

L. Miotti; K. P. Bastos; G. V. Soares; C. Driemeier; R. P. Pezzi; J. Morais; I. J. R. Baumvol; A. L. P. Rotondaro; M. R. Visokay; J. J. Chambers; M. Quevedo-Lopez; L. Colombo

2004-01-01

269

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses  

Microsoft Academic Search

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses were investigated by an X-ray diffraction\\u000a technique. It was observed that the stacking fault probability in Cu-10 Zn alloy increases as a logarithmic function of time.\\u000a This phenomena is associated with the segregation of zinc atoms to stacking faults. The ther mo mechanically treated (CW at\\u000a RT,

Tarik mer O?urtani

1975-01-01

270

Enhancement of field-emission properties in ZnO nanowire array by post-annealing in H2 ambient.  

PubMed

We studied the effects of post-annealing in H2 and O2 ambients on field-emission properties of vertically-aligned ZnO nanowire arrays synthesized by carbothermal reduction process. The turn-on electric field was dramatically decreased from 3.78 to 2.37 V/microm after post-annealing in H2 ambient, which was explained by both hydrogen passivation effects of deep levels and surface modification. In other words, we could observe significant decrease of deep level peak in photoluminescence measurements on hydrogen post-annealed ZnO nanowire array. And also hydrogen-related bonds are strongly increased from X-ray photoelectron spectroscopy measurements. These findings suggest that the concentration of conduction electrons increased by hydrogen post-annealing, which results in the enhanced tunneling probability of conduction electrons into the vacuum. PMID:19916451

Park, Kyung-Soo; Choi, Young-Jin; Ahn, Myoung-Won; Kim, Dong-Wan; Sung, Yun-Mo; Park, Jae-Gwan; Choi, Kyoung Jin

2009-07-01

271

Statistical phenomena in particle beams  

SciTech Connect

Particle beams are subject to a variety of apparently distinct statistical phenomena such as intrabeam scattering, stochastic cooling, electron cooling, coherent instabilities, and radiofrequency noise diffusion. In fact, both the physics and mathematical description of these mechanisms are quite similar, with the notion of correlation as a powerful unifying principle. In this presentation we will attempt to provide both a physical and a mathematical basis for understanding the wide range of statistical phenomena that have been discussed. In the course of this study the tools of the trade will be introduced, e.g., the Vlasov and Fokker-Planck equations, noise theory, correlation functions, and beam transfer functions. Although a major concern will be to provide equations for analyzing machine design, the primary goal is to introduce a basic set of physical concepts having a very broad range of applicability.

Bisognano, J.J.

1984-09-01

272

Thermodynamic constraints on fluctuation phenomena  

NASA Astrophysics Data System (ADS)

The relationships among reversible Carnot cycles, the absence of perpetual motion machines, and the existence of a nondecreasing globally unique entropy function form the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law of thermodynamics. Here we demonstrate that fluctuation phenomena can be incorporated into the traditional presentation, extending rather than restricting the domain of validity of the phenomenologically motivated second law. Consistency conditions lead to constraints upon the possible spectrum of thermal fluctuations. In a special case this uniquely selects the Gibbs canonical distribution and more generally incorporates the Tsallis distributions. No particular model of microscopic dynamics need be assumed.

Maroney, O. J. E.

2009-12-01

273

Thermodynamic constraints on fluctuation phenomena.  

PubMed

The relationships among reversible Carnot cycles, the absence of perpetual motion machines, and the existence of a nondecreasing globally unique entropy function form the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law of thermodynamics. Here we demonstrate that fluctuation phenomena can be incorporated into the traditional presentation, extending rather than restricting the domain of validity of the phenomenologically motivated second law. Consistency conditions lead to constraints upon the possible spectrum of thermal fluctuations. In a special case this uniquely selects the Gibbs canonical distribution and more generally incorporates the Tsallis distributions. No particular model of microscopic dynamics need be assumed. PMID:20365152

Maroney, O J E

2009-12-01

274

Insulation Phenomena of Compressed Air  

Microsoft Academic Search

Test data on impulse and 60-cycle voltage breakdown strength for compressed air with various electrode configurations are reported. The tests were made with rod-to-plane electrodes with spacings up to 8 inches and pressures to 250 psig (pounds per square inch gage). Breakdown phenomena of air insulation encountered in the development of an air insulated air-blast circuit breaker1 are reported. The

L. D. McConnell

1957-01-01

275

Multiparticle phenomena and Landau damping  

SciTech Connect

The purpose of this paper is to survey various methods of studying multiparticle phenomena in accelerators. Both experimental and theoretical methods are described. An effort has been made to emphasize the intuitive and qualitative aspects rather than the detailed mathematics. Some of the terms or concepts to be explained are coherent and incoherent tunes, normal modes, Landau damping, beam-transfer functions, and feedback. These are all of daily importance in the interpretation of colliding-beam observations and the control of performance.

Talman, R.

1987-02-25

276

Visualization of solidification front phenomena  

NASA Technical Reports Server (NTRS)

Directional solidification experiments have been utilized throughout the Materials Processing in Space Program to provide an experimental platform which minimizes variables in solidification experiments. Because of the wide-spread use of this experimental technique in space-based research, it has become apparent that a better understanding of all the phenomena occurring during solidification can be better understood if direct visualization of the solidification interface were possible.

Workman, Gary L.; Smith, Guy A.

1993-01-01

277

New phenomena searches at CDF  

SciTech Connect

The authors report on recent results from the Collider Detector at Fermilab (CDF) experiment, which is accumulating data from proton-antiproton collisions with {radical}s = 1.96 TeV at Run II of the Fermilab Tevatron. The new phenomena being explored include Higgs, Supersymmetry, and large extra dimensions. They also present the latest results of searches for heavy objects, which would indicate physics beyond the Standard Model.

Soha, Aron; /UC, Davis

2006-04-01

278

Mathematical Modeling of Diverse Phenomena  

NASA Technical Reports Server (NTRS)

Tensor calculus is applied to the formulation of mathematical models of diverse phenomena. Aeronautics, fluid dynamics, and cosmology are among the areas of application. The feasibility of combining tensor methods and computer capability to formulate problems is demonstrated. The techniques described are an attempt to simplify the formulation of mathematical models by reducing the modeling process to a series of routine operations, which can be performed either manually or by computer.

Howard, J. C.

1979-01-01

279

Finite element simulation of vacuum arc remelting  

NASA Astrophysics Data System (ADS)

Vacuum arc remelting is a process for producing homogeneous ingots of reactive and macrosegregation-sensitive alloys. A mathematical model of the transport phenomena in the ingot melt is presented together with a discussion of the various simplifying assumptions and approximations that make the problem tractable, with particular attention on transport in the interdendritic mushy zone and on the magnetohydrodynamics. The finite element method is used to discretize the equations for the non-isothermal flow problem and the quasi-static electromagnetic problem. Coupling of the finite element solutions for the two field problems is accomplished using the Parallel Virtual Machine software. An analysis of the fluid flow and heat transport in the melt pool of the solidifying ingot shows some of the factors that influence ingot quality during quasi-steady growth conditions.

Gartling, D. K.; Sackinger, P. A.

1997-06-01

280

Boron distribution in silicon after multiple pulse excimer laser annealing  

SciTech Connect

We have studied B redistribution in Si after excimer laser annealing (ELA) with multiple laser pulses. B was implanted with energies of 1 and 10 keV and doses of 1x10{sup 14} and 1x10{sup 15} cm{sup -2}. ELA with the number of pulses from 1 to 100 was performed at room temperature and 450 deg. C in vacuum. Irrespective of the implantation parameters and the ELA conditions used, a pile-up in the B concentration is observed near the maximum melting depth after ten pulses of ELA. Moreover, a detailed study has revealed that B accumulates at the maximum melt depth gradually with the number of ELA pulses. Besides, an increase in the carrier concentration is observed at the maximum melt depth, suggesting electrical activity of the accumulated B. Formation of Si-B complexes and vacancy accumulation during multiple ELA are discussed as possible mechanisms for the B build-up.

Monakhov, E.V.; Svensson, B.G.; Linnarsson, M.K.; La Magna, A.; Italia, M.; Privitera, V.; Fortunato, G.; Cuscuna, M.; Mariucci, L. [Department of Physics, Physical Electronics, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo (Norway); Royal Institute of Technology, Lab of Materials and Semiconductor Physics, P.O. Box Electrum 229, SE-164 40 Kista (Sweden); CNR-IMM, Stradale Primosole 50, 95121 Catania (Italy); CNR-IFN, Via Cineto Romano 42, 00156 Rome (Italy)

2005-08-22

281

Annealing of aromatic polyimide precursors  

NASA Technical Reports Server (NTRS)

A study has been made of the thermal behavior of polyimide precursors: an isomeric pair of crystals of the complex formed by p-phenylenediamine with the separated isomers of the di-isopropyl ester of pyromellitic acid. Specimens of this material were isothermally annealed in the temperature range 120 C to 170 C for periods of time up to 1 week. Although this temperature range is well below that customarily used for imidizations, the working hypothesis was that it would be more likely that a polymer embodying at least part of the precursor structure could be formed if the molecular motion was minimized to that actually required for the formation of the imide linkage. The progress of the annealing was followed by: infrared spectroscopy, differential thermal analysis, powder X-ray diffraction, and thermal gravimetric analysis. Single crystal X-ray analysis of the meta monomer yields a structure of chains of alternating acid and base and suggests that this monomer is amenable to polymerization with a minimum of geometrical disruption.

Wakelyn, N. T.

1975-01-01

282

Combining simulated annealing with local search heuristics  

Microsoft Academic Search

We introduce a meta-heuristic to combine simulated annealing with local search methods for CO problems. This new class of\\u000a Markov chains leads to significantly more powerful optimization methods than either simulated annealing or local search. The\\u000a main idea is to embed deterministic local search techniques into simulated annealing so that the chain explores only local\\u000a optima. It makes large, global

Olivier C. Martin; Steve W. Otto

1996-01-01

283

Avoiding Death by Vacuum  

NASA Astrophysics Data System (ADS)

The two-Higgs doublet model (2HDM) can have two electroweak breaking, CP-conserving, minima. The possibility arises that the minimum which corresponds to the known elementary particle spectrum is metastable, a possibility we call the "panic vacuum". We present analytical bounds on the parameters of the softly broken Peccei-Quinn 2HDM which are necessary and sufficient conditions to avoid this possibility. We also show that, for this particular model, the current LHC data already tell us that we are necessarily in the global minimum of the theory, regardless of any cosmological considerations about the lifetime of the false vacua.

Barroso, A.; Ferreira, P. M.; Ivanov, I.; Santos, R.; Silva, Joo P.

2013-07-01

284

Rapid Annealing Of Amorphous Hydrogenated Carbon  

NASA Technical Reports Server (NTRS)

Report describes experiments to determine effects of rapid annealing on films of amorphous hydrogenated carbon. Study represents first efforts to provide information for applications of a-C:H films where rapid thermal processing required. Major finding, annealing causes abrupt increase in absorption and concomitant decrease in optical band gap. Most of change occurs during first 20 s, continues during longer annealing times. Extend of change increases with annealing temperature. Researchers hypothesize abrupt initial change caused by loss of hydrogen, while gradual subsequent change due to polymerization of remaining carbon into crystallites or sheets of graphite. Optical band gaps of unannealed specimens on silicon substrates lower than those of specimens on quartz substrates.

Alterovitz, Samuel A.; Pouch, John J.; Warner, Joseph D.

1989-01-01

285

Electrical annealing for flexible organic light-emitting diodes having poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) anodes  

NASA Astrophysics Data System (ADS)

We present a postproduction method of electrical annealing (E-annealing) to improve the performance of flexible organic light-emitting diodes (FOLEDs) having conductive polymer anodes on a polyethersulfone substrate. The polymer that was used for the anodes was dimethylsulfoxide-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate). It was found that E-annealing of the fabricated FOLEDs can reduce the turn-on voltage and enhance the brightness with reduced flowing current, thereby enhancing the device efficiency. With the E-annealing method, we have successfully demonstrated efficient solution-processed green FOLEDs, which show a peak luminescence of 6 100 cd/m2 and a maximum current efficiency of 16.4 cd/A. An ion migration model to explain the phenomena related to the improvement of FOLEDs is also proposed.

Park, Byoungchoo; Park, Chan Hyuk; Yim, Younchan; Park, Jongwoon

2010-10-01

286

R&D ERL: Vacuum  

SciTech Connect

The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The cryostat vacuum thermally insulating the SRF cavities need only reduce the convective heat load such that heat loss is primarily radiation through several layers of multi-layer insulation and conductive end-losses which are contained by 5{sup o}K thermal transitions. Prior to cool down rough vacuum {approx}10{sup -5} torr range is established and maintained by a dedicated turbomolecular pump station. Cryopumping by the cold mass and heat shields reduces the insulating vacuum to 10{sup -7} torr range after cool down.

Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

2010-01-01

287

Influence of post-annealing on electrical, structural and optical properties of vanadium oxide thin films  

NASA Astrophysics Data System (ADS)

Vanadium oxide thin films were grown onto quartz substrates using the pulsed DC reactive magnetron sputtering technique at room temperature and afterwards post annealed under vacuum conditions in the temperature range from 75 to 230 C. The electrical resistance, temperature coefficient of resistance (TCR), optical energy gap and structural properties were investigated. The films are amorphous, nanoscale grained V2O5 phase and the mean grain size increases with increasing temperature. Additionally, the post-annealing at 230 C induces formation of both V2O5 and V4O9 phases and pinholes on the film surface. The temperature dependent variation of the electrical resistance indicates two activation energy areas corresponding to two TCR values for the films post annealed up to 180 C, but only one activation area was found after annealing at 230 C. Analyses of the absorption coefficient versus photon energy revealed a direct forbidden transition. The mean grain size and TCR values increase with increasing post-annealing temperature, whereas the optical energy gap and electrical resistance do not follow this tendency. The evolution of the structure and its correlation to the optical energy gap, electrical resistance, activation energy and TCR were discussed by means of the results obtained in the present study.

Mustafa kszo?lu, Ramis; Bilgi, P?nar; Y?ld?r?m, Mustafa; Deniz, Okan

2013-06-01

288

Synthesis of cobalt nanoparticles by ion implantation and effects of postimplantation annealing  

SciTech Connect

A study of the synthesis of Co nanoparticles by ion implantation and the effects of postimplantation annealing was carried out. Silica was implanted with 35 keV Co{sup +} ion beams to doses ranging from 8x10{sup 15} to 1x10{sup 17} atoms/cm{sup 2}. Nanoparticle size, distribution, and structure were ascertained via transmission electron microscopy measurements, which reveal the presence of spherical nanoparticles in both as-implanted and annealed samples. X-ray photoelectron spectroscopy show the chemical state of the nanoparticles in both as-implanted and annealed samples to be metallic. Temperature-dependent field-cooled and zero-field-cooled, susceptibility measurements indicated superparamagnetic behavior, which is analyzed by accounting for the size dispersion of the nanoparticles. Results showed that the magnetic properties of the specimen can be tailored by implantation conditions. Annealing in vacuum at 900 deg. C for up to 10 h leads to an increase of the average nanoparticle size and a broader size distribution. Mie scattering and magnetic force microscopy measurements provide evidence of a strong interaction among the nanoparticles in the annealed samples. The feasibility of obtaining small-dispersion size-controlled synthesis of Co nanoparticles at room temperature is illustrated.

Jacobsohn, L.G.; Hawley, M.E.; Cooke, D.W.; Hundley, M.F.; Thompson, J.D.; Schulze, R.K.; Nastasi, M. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2004-10-15

289

The Influence of Vacuum Circuit Breakers and Different Motor Models on Switching Overvoltages in Motor Circuits  

NASA Astrophysics Data System (ADS)

Switching of induction motors with vacuum circuit breakers continues to be a concern. In this paper the influence on statistical overvoltages of the stochastic characteristics of vacuum circuit breakers, high frequency models of motors and transformers, and network characteristics, including cable lengths and network topology are evaluated and a general view of the overvoltages phenomena is presented. Finally, a real case study on the statistical voltage levels and risk-of-failure resulting from switching of a vacuum circuit breaker in an industrial installation in Hong Kong is presented.

Wong, Cat S. M.; Snider, L. A.; Lo, Edward W. C.; Chung, T. S.

290

BWR core melt progression phenomena: Experimental analyses.  

National Technical Information Service (NTIS)

In the BWR Core Melt in Progression Phenomena Program, experimental results concerning severe fuel damage and core melt progression in BWR core geometry are used to evaluate existing models of the governing phenomena. These include control blade eutectic ...

L. J. Ott

1992-01-01

291

Correlated randomness and switching phenomena  

NASA Astrophysics Data System (ADS)

One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines have no perfect metronome in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. Further, many of these processes and structures have the remarkable feature of switching from one behavior to another as if by magic. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many spatial and temporal patterns in biology, medicine, and economics and even begin to characterize the switching phenomena that enables a system to pass from one state to another. Inspired by principles developed by A. Nihat Berker and scores of other statistical physicists in recent years, we discuss some applications of correlated randomness to understand switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that waters anomalies are related to a switching point (which is not unlike the tipping point immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not outliers (another Gladwell immortalization). Though more speculative, we support the idea of disease as arising from some kind of yet-to-be-understood complex switching phenomenon, by discussing data on selected examples, including heart disease and Alzheimer disease.

Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Kumar, P.; Plerou, V.; Preis, T.

2010-08-01

292

Transport phenomena in porous media  

NASA Astrophysics Data System (ADS)

The Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media, held July 14-23, 1985 in Newark, Del. and directed by Jacob Bear (Israel Institute of Technology, Haifa) and M. Yavuz Corapcioglu (City College of New York), under the auspices of NATO, was a sequel to the NATO Advanced Study Institute (ASI) held in 1982 (proceedings published as Fundamentals of Transport Phenomena in Porous Media, J. Bear, and M.Y. Corapcioglu (Ed.), Martinus Nijhoff, Dordrecht, the Netherlands, 1984). The meeting was attended by 106 participants and lecturers from 21 countries.As in the first NATO/ASI, the objective of this meetingwhich was a combination of a conference of experts and a teaching institute was to present and discuss selected topics of transport in porous media. In selecting topics and lecturers, an attempt was made to bridge the gap that sometimes exists between research and practice. An effort was also made to demonstrate the unified approach to the transport of mass of a fluid phase, components of a fluid phase, momentum, and heat in a porous medium domain. The void space may be occupied by a single fluid phase or by a number of such phases; each fluid may constitute a multicomponent system; the solid matrix may be deformable; and the whole process of transport in the system may take place under nonisothermal conditions, with or without phase changes. Such phenomena are encountered in a variety of disciplines, e.g., petroleum engineering, civil engineering (in connection with groundwater flow and contamination), soil mechanics, and chemical engineering. One of the goals of the 1985 NATO/ASI, as in the 1982 institute, was to bring together experts from all these disciplines and enhance communication among them.

Bear, Jacob; Corapcioglu, M. Yavuz

293

Phenomena and Diosignes of Aratous  

NASA Astrophysics Data System (ADS)

Aratous (305-240B.C.) was a singular intellectual, writer and poet which engage himself to compose a very interesting astronomical poet, using the "Dactylous sixstage' style, the formal style of the ancient Greek Epic poetry. This astronomic poem of Aratous "Phenomena and Diosignes" became very favorite reading during the Alexandrine, the Romman and the Byzandin eras as well and had received many praises from significant poets and particularly from Hipparchous and from Theonas from Alexandria, an astronomer of 4rth century A.C.(in Greeks)

Avgoloupis, S. I.

2013-01-01

294

Miniature ion-sorption vacuum pump with CNT field-emission electron source  

NASA Astrophysics Data System (ADS)

Generation and maintenance of the high vacuum in the MEMS-type (micro-electro-mechanical system) microsystems and vacuum nanoelectronics devices remain a major problem today. The phenomena of gas desorption from the surface of a microcavity and outgassing of materials limit the vacuum to the level of about 10-1 Pa. In this paper, a new MEMS-type micropump for generating a high vacuum in a microcavity is presented. The main component of the ion-sorption micropump is a carbon nanotube (CNT) field-emission electron source. Test structures of the electron source with electrophoretically deposited CNT have been fabricated and measured. A satisfactory value of the emission current and a low turn-on voltage have been obtained. The elaborated electron source has been applied to the micropump structure; it has enabled us to achieve a vacuum level below 10-3 Pa.

Grzebyk, T.; Grecka-Drzazga, A.

2013-01-01

295

Cosmology with a decaying vacuum  

NASA Astrophysics Data System (ADS)

Properties of unstable false vacuum states are analyzed from the point of view of the quantum theory of unstable states. Some of false vacuum states survive up to times when their survival probability has a non-exponential form. At times much latter than the transition time, when contributions to the survival probability of its exponential and non-exponential parts are comparable, the survival probability as a function of time t has an inverse power-like form. We show that at this time region the instantaneous energy of the false vacuum states tends to the energy of the true vacuum state as 1/t2 for t --> ?.

Urbanowski, K.; Szyd?owski, M.

2013-02-01

296

Low partial discharge vacuum feedthrough  

NASA Technical Reports Server (NTRS)

Relatively discharge free vacuum feedthrough uses silver-plated copper conductor jacketed by carbon filled silicon semiconductor to reduce concentrated electric fields and minimize occurrence of partial discharge.

Benham, J. W.; Peck, S. R.

1979-01-01

297

Vacuum leak detector and method  

DOEpatents

Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

Edwards, Jr., David (7 Brown's La., Bellport, NY 11713)

1983-01-01

298

"Un-annealed and Annealed Pd Ultra-Thin Film on SiC Characterized by Scanning Probe Microscopy and X-ray Photoelectron Spectroscopy"  

NASA Technical Reports Server (NTRS)

Pd/SiC has been used as a hydrogen and a hydrocarbon gas sensor operated at high temperature. UHV (Ultra High Vacuum)-Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) techniques were applied to study the relationship between the morphology and chemical compositions for Pd ultra-thin films on SiC (less than 30 angstroms) at different annealing temperatures. Pd ultra-thin film on 6H-SiC was prepared by the RF sputtering method. The morphology from UHV-STM and AFM shows that the Pd thin film was well deposited on SiC substrate, and the Pd was partially aggregated to round shaped participates at an annealing temperature of 300 C. At 400 C, the amount of surface participates decreases, and some strap shape participates appear. From XPS, Pd2Si was formed on the surface after annealing at 300 C, and all Pd reacted with SiC to form Pd2Si after annealing at 400 C. The intensity of the XPS Pd peak decreases enormously at 400 C. The Pd film diffused into SiC, and the Schottky barrier height has almost no changes. The work shows the Pd sicilides/SiC have the same electronic properties with Pd/SiC, and explains why the Pd/SiC sensor still responds to hydrogen at high operating temperatures.

Lu, W. J.; Shi, D. T.; Elshot, K.; Bryant, E.; Lafate, K.; Chen, H.; Burger, A.; Collins, W. E.

1998-01-01

299

Natural phenomena hazards, Hanford Site, Washington  

SciTech Connect

This document presents the natural phenomena hazard loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, and supports development of double-shell tank systems specifications at the Hanford Site in south-central Washington State. The natural phenomena covered are seismic, flood, wind, volcanic ash, lightning, snow, temperature, solar radiation, suspended sediment, and relative humidity.

Conrads, T.J.

1998-09-29

300

Multi-stage annealing of defects in ion-implanted double-barrier diodes  

NASA Astrophysics Data System (ADS)

The d.c. and a.c. characteristics of double-barrier diodes have been used to probe the large-scale annealing of defects within ion-implanted GaAs. Multi-stage annealing of defects was elucidated by the staged recovery of resonant tunnelling through ion-implanted diodes. Surprisingly, the current - voltage characteristics of some ion-implanted diodes after very rapid anneals were qualitatively identical to the as-grown characteristics, but the peak-current density was two orders of magnitude lower. This is explained by the creation of small percolation paths of as-grown material during the initial stages of annealing, where these paths surrounded clusters of defects. A simple capacitance model based on the creation of these percolation paths is described, and is consistent with the capacitance - voltage data. The idea that small-area percolation paths of as-grown material were created within the ion-implanted DBDs during very rapid annealing was supported by the observation of very-low bias resonant tunnelling and single-electron switching at 4.2 K. Both these phenomena are usually observed only within small-area pristine DBDs.

Billen, K.; Kelly, M. J.; Gwilliam, R. M.; Hutchinson, S.; Eaves, L.; Henini, M.; Foster, T. J.

1997-10-01

301

Effects of thermal annealing on the evolution of He bubbles in zirconia  

NASA Astrophysics Data System (ADS)

Single crystals of yttria-stabilized zirconia were implanted with 100 keV He ions at two fluences of 9 1016 and 3 1017 cm?2 (5 and 17 He at.%). In order to investigate the effect of thermal annealing on the evolution of both zirconia lattice and implanted He, the samples were annealed at several temperatures ranging from 500 C to 1400 C. Three complementary analysis techniques, RBS/C, AFM and TEM were used to study structural damage and surface morphology of the crystal before and after implantation. Results show different He evolution phenomena under the two implantation fluences. It is inferred that, at the lower fluence, the migration and agglomeration of He ions lead to bubble formation after annealing. These bubbles jack up sample surface causing the deformation of surface region and the damage level of surface region increase accordingly. As the temperature continues to increase, He gradually releases and the damage recovers. However, at the higher fluence, the He concentration is sufficient to induce bubble precipitation without annealing. He release and damage recovering is less efficient upon annealing.

Kong, Shuyan; Velisa, Gihan; Debelle, Aurlien; Yang, Tengfei; Wang, Chenxu; Thom, Lionel; Xue, Jianming; Yan, Sha; Wang, Yugang

2014-05-01

302

Controlled solvent vapour annealing for polymer electronics  

Microsoft Academic Search

Solvent vapour annealing (SVA) is demonstrated as an attractive method to anneal polymer blend and block copolymer thin films at low temperatures. It is especially suitable for organic electronics, where sensitive materials with strong intermolecular interactions are used. We demonstrate the effect of solvent vapour exposure on the film properties of a perylene bisimide acrylate (PPerAcr) side-chain polymer with strong

Sven Httner; Michael Sommer; Arnaud Chiche; Georg Krausch; Ullrich Steiner; Mukundan Thelakkat

2009-01-01

303

Annealing of Radiation Defects in Semiconductors  

Microsoft Academic Search

Radiation-induced defects studied through changes in conductivity and ; Hall coefficient have been observed to anneal in a number of different ; temperature ranges. Only those processes occurring above 80 deg K and involving ; defects created by electron irradiation have been considered in this paper. It ; has been found that the ftrst annealing process in n-type germanium occurs

W. L. Brown; W. M. Augustyniak; T. R. Waite

1959-01-01

304

Hybrid parallel tempering and simulated annealing method  

Microsoft Academic Search

In this paper, we propose a new hybrid scheme of parallel tempering and simulated annealing (hybrid PT\\/SA). Within the hybrid PT\\/SA scheme, a composite system with multi- ple conformations is evolving in parallel on a temperature ladder with various transition step sizes. The simulated annealing (SA) process uses a cooling scheme to decrease the temperature values in the temperature ladder

Yaohang Li; Vladimir A. Protopopescu; Nikita Arnold; Xinyu Zhang; Andrey Gorin

2009-01-01

305

Characterization of AgInS2 thin films prepared by vacuum evaporation  

NASA Astrophysics Data System (ADS)

We characterized AgInS2 thin films prepared by vacuum evaporation. In the case of thin films annealed at 400 C, diffraction peaks were observed only for the chalcopyrite AgInS2 phase. The chemical composition of the thin films annealed at 400 C was 26.5 at% Ag, 23.8 at% In, and 49.7 at% S. PL spectra of the AgInS2 thin films at 10.7 K showed peaks at 1.70, 1.80, and 1.83 eV. The PL peak at1.80 eV was attributed to sulfur deficiency.

Akaki, Yoji; Yamashita, Kyohei; Yoshitake, Tsuyoshi; Nakamura, Shigeuki; Seto, Satoru; Tokuda, Takahiro; Yoshino, Kenji

2012-08-01

306

Uranium Pyrophoricity Phenomena and Prediction  

SciTech Connect

We have compiled a topical reference on the phenomena, experiences, experiments, and prediction of uranium pyrophoricity for the Hanford Spent Nuclear Fuel Project (SNFP) with specific applications to SNFP process and situations. The purpose of the compilation is to create a reference to integrate and preserve this knowledge. Decades ago, uranium and zirconium fires were commonplace at Atomic Energy Commission facilities, and good documentation of experiences is surprisingly sparse. Today, these phenomena are important to site remediation and analysis of packaging, transportation, and processing of unirradiated metal scrap and spent nuclear fuel. Our document, bearing the same title as this paper, will soon be available in the Hanford document system [Plys, et al., 2000]. This paper explains general content of our topical reference and provides examples useful throughout the DOE complex. Moreover, the methods described here can be applied to analysis of potentially pyrophoric plutonium, metal, or metal hydride compounds provided that kinetic data are available. A key feature of this paper is a set of straightforward equations and values that are immediately applicable to safety analysis.

DUNCAN, D.R.

2000-04-20

307

Nonstationary Phenomena in the Heliosheath  

NASA Astrophysics Data System (ADS)

As Voyagers (V1 and V2) are approaching the heliopause (HP), they keep delivering important information about the solar wind (SW) behavior which sometimes appears to be substantially different at V1 and V2 locations. We argue that the observed differences may be attributed to SW variations. In particular, negative values of the radial velocity component derived from V1 observations may be due to the presence of time-dependent magnetic barriers formed due to the slow/fast wind interactions in the vicinity of solar cycle minima. The inner heliosheath is the venue of wave interaction, MHD instabilities, and turbulence. We further investigate these phenomena in the HP vicinity using a new, based on the Ulysses observations, solar cycle model. We show that some puzzling observational data, such as the difference in the heliocentric distances at which V1 and V2 crossed the termination shock, may be attributed to time-dependent effects. We also use other time-dependent sets of observational boundary conditions, e.g., interplanetary scintillation and OMNI data. Phenomena affecting the stability and shape of the HP are also discussed in the context of our time-dependent simulations. The satisfaction of the 2-3 kHz radio emission criteria beyond the HP is analyzed. Numerical results are validated by their comparison with observational data.

Pogorelov, N. V.; Borovikov, S. N.; Ebert, R. W.; Heerikhuisen, J.; Kim, T. K.; Kryukov, I.; Richardson, J. D.; Suess, S. T.; Zank, G. P.

2012-12-01

308

Direct and pulsed current annealing of p-MOSFET based dosimeter: the "MOSkin".  

PubMed

Contemporary radiation therapy (RT) is complicated and requires sophisticated real-time quality assurance (QA). While 3D real-time dosimetry is most preferable in RT, it is currently not fully realised. A small, easy to use and inexpensive point dosimeter with real-time and in vivo capabilities is an option for routine QA. Such a dosimeter is essential for skin, in vivo or interface dosimetry in phantoms for treatment plan verification. The metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector is one of the best choices for these purposes, however, the MOSFETs sensitivity and its signal stability degrade after essential irradiation which limits its lifespan. The accumulation of positive charge on the gate oxide and the creation of interface traps near the silicon-silicon dioxide layer is the primary physical phenomena responsible for this degradation. The aim of this study is to investigate MOSFET dosimeter recovery using two proposed annealing techniques: direct current (DC) and pulsed current (PC), both based on hot charged carrier injection into the gate oxide of the p-MOSFET dosimeter. The investigated MOSFETs were reused multiple times using an irradiation-annealing cycle. The effect of the current-annealing parameters was investigated for the dosimetric characteristics of the recovered MOSFET dosimeters such as linearity, sensitivity and initial threshold voltage. Both annealing techniques demonstrated excellent results in terms of maintaining a stable response, linearity and sensitivity of the MOSFET dosimeter. However, PC annealing is more preferable than DC annealing as it offers better dose response linearity of the reused MOSFET and has a very short annealing time. PMID:24648245

Alshaikh, Sami; Carolan, Martin; Petasecca, Marco; Lerch, Michael; Metcalfe, Peter; Rosenfeld, Anatoly

2014-06-01

309

Control Dewar Secondary Vacuum Container  

SciTech Connect

This engineering note provides background information regarding the control dewar secondary vacuum container. The secondary vacuum container has it's origin with the CDP control dewar design. The name secondary vacuum container replaced the CDP term 'Watt can' which was named after Bob Watt (SLAC), a PAC/DOE review committee member who participated in a review of CDP and recommended a secondary vacuum enclosure. One of the most fragile parts of the control dewar design is the ceramic electrical feed throughs located in the secondary vacuum container. The secondary vacuum container is provided to guard against potential leaks in these ceramic insulating feed throughs. The secondary vacuum container has a pumping line separate from the main solenoid/control dewar insulating vacuum. This pumping line is connected to the inlet of the turbo pump for initial pumpdown. Under normal operation the container is isolated. Should a feedthrough develop a small leak, alternate pumping arrangements for the secondary vacuum container could be arranged. The pressure in the secondary vacuum container should be kept in a range that the breakdown voltage is kept at a maximum. The breakdown voltage is known to be a function of pressure and is described by a Paschen curve. I cannot find a copy of the curve at this time, but from what I remember, the breakdown voltage is a minimum somewhere around 10-3 torr. Ideally the pressure in the secondary vacuum can should be kept very low, around 10 E-6 or 10 E-7 torr for maximum breakdown voltage. If however a leak developed and this was not possible, then one could operate at a pressure higher than the minima point.

Rucinski, R.; /Fermilab

1993-10-04

310

Crystal growth and annealing method and apparatus  

DOEpatents

A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing. An embodiment of the present invention comprises a secondary heater incorporated into a conventional crystal growth and annealing apparatus. The secondary heater supplies heat to minimize the temperature gradients in the crystal during the annealing process. The secondary heater can mount near the bottom of the crucible to effectively maintain appropriate temperature gradients.

Gianoulakis, Steven E. (Albuquerque, NM); Sparrow, Robert (North Brookfield, MA)

2001-01-01

311

Reduced annealing temperatures in silicon solar cells  

NASA Technical Reports Server (NTRS)

Cells irradiated to a fluence of 5x10,000,000,000,000/square cm showed short circuit current on annealing at 200 C, with complete annealing occurring at 275 C. Cells irradiated to 100,000,000,000,000/square cm showed a reduction in annealing temperature from the usual 500 to 300 C. Annealing kinetic studies yield an activation energy of (1.5 + or - 2) eV for the low fluence, low temperature anneal. Comparison with activation energies previously obtained indicate that the presently obtained activation energy is consistent with the presence of either the divacancy or the carbon interstitial carbon substitutional pair, a result which agrees with the conclusion based on defect behavior in boron-doped silicon.

Weinberg, I.; Swartz, C. K.

1981-01-01

312

Vacuum thermal insulation panel  

SciTech Connect

A vacuum thermal insulation panel comprises a pair of laminated plastic and aluminum sheets together with a plastic edge strip sealed to the edges of the sheets so as to define an evacuable volume in which a glass fiber mat is disposed. The insulation panel of the present invention takes advantage of the light-weight, low cost and low thermal conductivity of plastic materials to form an evacuable volume into which a glass fiber insulating mat is disposed for support of the panel which is evacuated to provide improved thermal insulation. Additionally, a gas permeation barrier is employed on the edge strip of the panel to minimize gas permeation at its edges. A metal foil layer provides gas permeation protection through the large surface areas of the sheets themselves.

Young, J.R.; Schreck, R.M.

1984-04-24

313

Pseudoredundant vacuum energy  

SciTech Connect

We discuss models that can account for today's dark energy. The underlying cosmological constant may be Planck scale but starts as a redundant coupling which can be eliminated by a field redefinition. The observed vacuum energy arises when the redundancy is explicitly broken, say by a nonminimal coupling to curvature. We give a recipe for constructing models, including R+1/R-type models, that realize this mechanism and satisfy all solar system constraints on gravity. A similar model, based on Gauss-Bonnet gravity, provides a technically natural explanation for dark energy and exhibits an interesting seesaw behavior: a large underlying cosmological constant gives rise to both low- and high-curvature solutions. Such models could be statistically favored in the string landscape.

Batra, Puneet; Hinterbichler, Kurt; Hui, Lam; Kabat, Daniel [Institute for Strings, Cosmology and Astroparticle Physics and Department of Physics, Columbia University, New York, New York 10027 (United States)

2008-08-15

314

Vacuum Powder Injector  

NASA Technical Reports Server (NTRS)

Method developed to provide uniform impregnation of bundles of carbon-fiber tow with low-solubility, high-melt-flow polymer powder materials to produce composite prepregs. Vacuum powder injector expands bundle of fiber tow, applies polymer to it, then compresses bundle to hold powder. System provides for control of amount of polymer on bundle. Crystallinity of polymer maintained by controlled melt on takeup system. All powder entrapped, and most collected for reuse. Process provides inexpensive and efficient method for making composite materials. Allows for coating of any bundle of fine fibers with powders. Shows high potential for making prepregs of improved materials and for preparation of high-temperature, high-modulus, reinforced thermoplastics.

Working, Dennis C.

1991-01-01

315

LIGO vacuum system study  

NASA Technical Reports Server (NTRS)

A laser interferometer gravitational wave observatory (LIGO) is being developed with sensitivities which will have a high probability of detecting gravitational waves from astrophysical sources. A major component of LIGO is a total of 16 km of 1.2 m (48 inch) diameter tube at a pressure of less than 10 to the minus 8th power torr. It will be of 304L stainless steel procured directly from the steel mills with the initial hydrogen content specially reduced. Projections of the outgassing rates of hydrogen and of water vapor as a function of time are given and the uncertainties discussed. Based on these, a preliminary analysis of the vacuum system is presented.

Livas, Jeffrey C.; Moore, Boude C.

1988-01-01

316

Vacuum Enhanced Cutaneous Biopsy Instrument  

SciTech Connect

A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

Collins, Joseph

1999-06-25

317

Vacuum barrier for excimer lasers  

Microsoft Academic Search

This patent describes a vacuum barrier for separating a region of vacuum from a pressurized gaseous region in an excimer laser. It comprises a first thin layer of metal having a thickness in the range of 2000-4000 Angstroms; a first thin layer of polyimide having a thickness of approximately 1 mil overlying the first thin layer of metal; a second

Shuter

1992-01-01

318

Vacuum pyrolysis of sugarcane bagasse  

Microsoft Academic Search

The objective of this study was to provide background data on sugarcane bagasse vacuum pyrolysis. Product yields and properties were investigated. Vacuum pyrolysis tests were performed at bench and pilot plant scales. The bagasse finest particles with a diameter smaller than 450 ?m were removed in order to overcome difficulties caused by their low density and high ash content. In

Abdelkader Chaala; Christian Roy

2002-01-01

319

Purifying Aluminum by Vacuum Distillation  

NASA Technical Reports Server (NTRS)

Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents.

Du Fresne, E. R.

1985-01-01

320

Vacuum outgassing of various materials  

Microsoft Academic Search

A gas analytical system for measuring the evolved gases from materials during vacuum degassing is discussed. The outgassing data are based upon the throughput measurement and a computer-controlled quadrupole mass spectrometer allows the determination of residual gas species. A variety of materials have been tested in the ''as-received'' condition at room temperature vacuum exposure. Test results are presented for materials

E. D. Erikson; T. G. Beat; D. D. Berger; B. A. Frazier

1984-01-01

321

Vacuum outgassing of various materials  

Microsoft Academic Search

A gas analytical system for measuring the evolved gases from materials during vacuum degassing is discussed. The outgassing data are based upon the throughput measurement and a computer-controlled quadrupole mass spectrometer allows the determination of residual gas species. A variety of materials have been tested in the as received condition at room-temperature vacuum exposure. Test results are presented for some

E. D. Erikson; T. G. Beat; D. D. Berger; B. A. Frazier

1983-01-01

322

Vacuum outgassing of various materials  

Microsoft Academic Search

A gas analytical system for measuring the evolved gases from materials during vacuum degassing is discussed. The outgassing data are based upon the throughput measurement and a computer-controlled quadrupole mass spectrometer allows the determination of residual gas species. A variety of materials have been tested in the as received condition at room temperature vacuum exposure. Test results are presented for

E. D. Erikson; T. G. Beat; D. D. Berger; B. A. Frazier

1983-01-01

323

Vacuum enhanced cutaneous biopsy instrument  

DOEpatents

A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

Collins, Joseph (St. Petersburg, FL)

2000-01-01

324

Vacuum Gas Tungsten Arc Welding  

NASA Technical Reports Server (NTRS)

A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

Weeks, J. L.; Todd, D. T.; Wooten, J. R.

1997-01-01

325

Vacuum carburizingprocess optimization  

Microsoft Academic Search

An increased interest in vacuum carburizing concept is being observed in the last years all around the world as a result of the progress in designing of modern furnaces for thermo-chemical treatment under low pressure and of better knowledge of physico-chemistry of these processes. This in turn allows a precise control with aid of computer simulations. The vacuum carburizing simulation

P. Kula; R. Pietrasik; K. Dybowski

2005-01-01

326

Vacuum flash evaporated polymer composites  

DOEpatents

A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

Affinito, J.D.; Gross, M.E.

1997-10-28

327

Breather cloth for vacuum curing  

NASA Technical Reports Server (NTRS)

Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

Reed, M. W.

1979-01-01

328

Combined heat transfer of radiation and conduction in stacked radiation shields for vacuum insulation panels  

Microsoft Academic Search

Combined heat transfer of radiation and conduction considering depthwise conduction phenomena in stacked radiation shields for vacuum insulation panels (VIPs) having an artificial core structure is investigated. The purpose of this study is to establish a reliable analysis method for actual shield design. A one-dimensional problem is first analyzed. Actual two-dimensional problem is simplified for theoretical modeling and the depthwise

Choonghyo Jang; Jongmin Kim; Tae-Ho Song

2011-01-01

329

Recovery of breakdown strength of a vacuum interrupter after extinction of high currents  

Microsoft Academic Search

Relevant phenomena during the period of the recovery of the dielectric strength of vacuum interrupter (VI) are reviewed. Metal vapor, residual charge and the effects of molten contact surfaces reduce the breakdown strength after the interruption of high currents. Metal droplets seem to play only a secondary role during the recovery phase. Instability of liquid protrusions is suspected to initiate

E. Schade; E. Dullni

2002-01-01

330

Digital quantum batteries: Energy and information storage in nano vacuum tube arrays  

Microsoft Academic Search

Dielectric material between capacitor electrodes increases the capacitance. However, when the electric field exceeds a threshold, electric breakdown in the dielectric discharges the capacitor sud- denly and the stored energy is lost. We show that nano vacuum tubes do not have this problem because (i) electric breakdown can be suppressed with quantization phenomena, and (ii) the ca- pacitance is large

Alfred W. Hubler; Onyeama Osuagwu

331

The response of watercress ( Nasturtium officinale) to vacuum impregnation: Effect of an antifreeze protein type I  

Microsoft Academic Search

The setting up of methodologies that reduce the size of ice crystals and reduce or inhibit the recrystallisation phenomena could have an extraordinary significance in the final quality of frozen products and consequently bring out new market opportunities. In this work, the effect of an antifreeze protein type I (AFP-I), by vacuum impregnation (VI), on frozen watercress was studied. The

Rui M. S. Cruz; Margarida C. Vieira; Cristina L. M. Silva

2009-01-01

332

Application of Seismic Design Requirements to Cold Vacuum Drying (CVD) Facility Structures and Systems and Components  

SciTech Connect

The methodology followed in assignment of Performance Class (PC) for Natural Phenomena Hazards (NPH) seismic loads for Cold Vacuum Drying Facility (CVDF) Structures, Systems and Components is defined. The loading definition associated with each PC and structure, system and component is then defined.

CREA, B.A.

1999-11-15

333

Multiscale Modeling of the Vacuum Arc Remelting Process for the Prediction on Microstructure Formation  

Microsoft Academic Search

The final solidification structures of Vacuum Arc Remelting (VAR) ingots depend on the temperature distribution and fluid motion within the molten pool. In this paper, a three-dimensional multi-physics macroscale model for VAR is developed, based on the modular CFD software PHYSICA. This model is used to provide estimates of process parameters and to study complex physical phenomena, such as liquid

Lang Yuan; Georgi Djambazov; Peter D. Lee; Koulis Pericleous

2009-01-01

334

The AGS Booster vacuum systems  

SciTech Connect

The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10{sup {minus}11} mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200{degree}C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs.

Hseuh, H.C.

1989-01-01

335

48 Optical Illusions & Visual Phenomena  

NSDL National Science Digital Library

Have you ever wondered how different optical illusions work? This fun, informative, and very cool website developed by ophthalmologist Dr. Michael Bach of the University of Freiburg's Medical School introduces 48 interactive visual illusions and phenomena. The illusions are animated and accompanied by explanations that help visitors make sense of their perceptual responses. Major illusion categories include: Motion & Time, Luminance & Contrast, Colour, Cognitive, and more. The site is still in progress, and Dr. Bach encourages both general feedback, and additional scientific information for improving the illusion explanations. The second site, also from Professor Bach, presents site users with an interactive, online Visual Acuity Test. Note: The Contrast component of the Test has yet to be implemented.

336

Critical phenomena in ferromagnetic superlattices  

NASA Astrophysics Data System (ADS)

Within the framework of the high-temperature series expansions technique, we examine the phase transition and the critical phenomena of a two-component superlattice with simple cubic structure, through three models: Ising, XY and Heisenberg. The reduced critical temperature of the system is studied as a function of the thickness of the constituents and the exchange interactions in each material, and within the interface. We show the existence of a critical thickness of the unit cell at which the reduced critical temperature of the binary superlattice remains insensitive to the exchange coupling within the interfaces. The values of the effective critical exponent ? eff associated with the magnetic susceptibility agreed with the universal classes in the limit cases where the superlattice is still comparable to an infinite simple cubic lattice. We attribute the breakdown in the universality hypothesis to the crossover effects.

Bakrim, H.

2005-06-01

337

Unidentified phenomena - Unusual plasma behavior?  

NASA Astrophysics Data System (ADS)

The paper describes observations of a phenomenon belonging to the UFO category and the possible causes of these events. Special attention is given to an event which occurred during the night of September 19-20, 1974, when a huge 'star' was observed over Pertrozavodsk (Russia), consisting of a bright-white luminous center, emitting beams of light, and a less bright light-blue shell. The star gradually formed a cometlike object with a tail consisting of beams of light and started to descend. It is suggested that this event was related to cosmic disturbances caused by an occurrence of unusually strong solar flares. Other examples are presented that relate unusual phenomena observed in space to the occurrence of strong magnetic turbulence events.

Avakian, S. V.; Kovalenok, V. V.

1992-06-01

338

Onset phenomena in MPD thrusters  

NASA Technical Reports Server (NTRS)

An experimental study has clarified some aspects of MPD thruster onset phenomena. The steep increase in terminal voltage that occurs as the onset current is approached may have different causes, depending on the propellant injection geometry. For propellant injection at the cathode radius, terminal voltage increase corresponds to a growing anode fall voltage; for injection at a larger radius, the increase is related to the back emf in the near-cathode plasma. The formation of the onset current pattern within the arc has been mapped experimentally as the thruster responds to an input current step which rises from below onset to the onset value. The appearance of terminal voltage hash at onset correlates with the extension into the exhaust region of a significant fraction of the arc current.

Barnett, J. W.; Jahn, R. G.

1985-01-01

339

In-vessel phenomena -- CORA  

SciTech Connect

Experiment-specific models have been employed since 1986 by Oak Ridge National Laboratory (ORNL) severe accident analysis programs for the purpose of boiling water reactor experimental planning and optimum interpretation of experimental results. The large integral tests performed to date, which start from an initial undamaged core state, have involved significantly different-from-prototypic boundary and experimental conditions because of either normal facility limitations or specific experimental constraints. These experiments (ACRR: DF-4, NRU: FLHT-6, and CORA) were designed to obtain specific phenomenological information such as the degradation and interaction of prototypic components and the effects on melt progression of control-blade materials and channel boxes. Applications of ORNL models specific to the KfK CORA-16 and CORA-17 experiments are discussed and significant findings from the experimental analyses such as the following are presented: applicability of available Zircaloy oxidation kinetics correlations; influence of cladding strain on Zircaloy oxidation; influence of spacer grids on the structural heatup; and the impact of treating the gaseous coolant as a gray interacting medium. The experiment-specific models supplement and support the systems-level accident analysis codes. They allow the analyst to accurately quantify the observed experimental phenomena and to compensate for the effect of known uncertainties. They provide a basis for the efficient development of new models for phenomena that are currently not modeled (such as material interactions). They can provide validated phenomenological models (from the results of the experiments) as candidates for incorporation in the systems-level whole-core'' codes.

Ott, L.J.; van Rij, W.I.

1991-01-01

340

Crystal growth behaviour in Au-ZnO nanocomposite under different annealing environments and photoswitchability  

NASA Astrophysics Data System (ADS)

The growth of gold nanoparticles and ZnO nanorods in atom beam co-sputtered Au-ZnO nanocomposite (NC) system by annealing at two different ambient conditions is demonstrated in this work. Annealing in a furnace at 600 C (air environment) confirmed the formation of ZnO nanorods surrounded with Au nanoparticles. In-situ annealing inside a transmission electron microscope (TEM) led to the formation of gold nanocrystals with different polygonal shapes. TEM micrographs were obtained in real time at intermediate temperatures of 300 C, 420 C, and 600 C under vacuum. The growth mechanisms of Au nanocrystals and ZnO nanorods are discussed in the framework of Au-Zn eutectic and Zn-melting temperatures in vacuum and air, respectively. Current-voltage responses of Au-ZnO NC nanorods in dark as well as under light illumination have been investigated and photoswitching in Au-ZnO NC system is reported. The photoswitching has been discussed in terms of Au-ZnO band-diagram.

Mishra, Y. K.; Chakravadhanula, V. S. K.; Hrkac, V.; Jebril, S.; Agarwal, D. C.; Mohapatra, S.; Avasthi, D. K.; Kienle, L.; Adelung, R.

2012-09-01

341

Effect of Post-Growth Annealing on Morphology of Ge Mesa Selectively Grown on Si  

NASA Astrophysics Data System (ADS)

Effect of the post-growth annealing on the morphology of a Ge mesa selectively grown on Si was studied from the viewpoint of near-infrared photodiode applications. By ultrahigh-vacuum chemical vapor deposition, Ge mesas were selectively grown at 600C on Si (001) substrates partially covered with SiO2 masks. The as-grown Ge mesas showed trapezoidal cross-sections having a top (001) surface and {311} sidewall facets, as similar to previous reports. However, after the subsequent post-growth annealing at -800C in the ultrahigh-vacuum chamber, the mesas were deformed into rounded shapes having a depression at the center and mounds near the edges. Such a deformation cannot be observed for the samples annealed once after cooled and exposed to the air. The residual hydrogen atoms on the Ge surface from the germane (GeH4) decomposition is regarded as a trigger to the observed morphological instability, while the final mesa shape is determined in order to minimize a sum of the surface and/or strain energies.

Park, Sungbong; Ishikawa, Yasuhiko; Tsuchizawa, Tai; Watanabe, Toshifumi; Yamada, Koji; Itabashi, Sei-Ichi; Wada, Kazumi

342

PREFACE Integrability and nonlinear phenomena Integrability and nonlinear phenomena  

NASA Astrophysics Data System (ADS)

Back in 1967, Clifford Gardner, John Greene, Martin Kruskal and Robert Miura published a seminal paper in Physical Review Letters which was to become a cornerstone in the theory of integrable systems. In 2006, the authors of this paper received the AMS Steele Prize. In this award the AMS pointed out that `In applications of mathematics, solitons and their descendants (kinks, anti-kinks, instantons, and breathers) have entered and changed such diverse fields as nonlinear optics, plasma physics, and ocean, atmospheric, and planetary sciences. Nonlinearity has undergone a revolution: from a nuisance to be eliminated, to a new tool to be exploited.' From this discovery the modern theory of integrability bloomed, leading scientists to a deep understanding of many nonlinear phenomena which is by no means reachable by perturbation methods or other previous tools from linear theories. Nonlinear phenomena appear everywhere in nature, their description and understanding is therefore of great interest both from the theoretical and applicative point of view. If a nonlinear phenomenon can be represented by an integrable system then we have at our disposal a variety of tools to achieve a better mathematical description of the phenomenon. This special issue is largely dedicated to investigations of nonlinear phenomena which are related to the concept of integrability, either involving integrable systems themselves or because they use techniques from the theory of integrability. The idea of this special issue originated during the 18th edition of the Nonlinear Evolution Equations and Dynamical Systems (NEEDS) workshop, held at Isola Rossa, Sardinia, Italy, 16-23 May 2009 (http://needs-conferences.net/2009/). The issue benefits from the occasion offered by the meeting, in particular by its mini-workshops programme, and contains invited review papers and contributed papers. It is worth pointing out that there was an open call for papers and all contributions were peer reviewed according to the standards of the journal. The selection of papers in this issue aims to bring together recent developments and findings, even though it consists of only a fraction of the impressive developments in recent years which have affected a broad range of fields, including the theory of special functions, quantum integrable systems, numerical analysis, cellular automata, representations of quantum groups, symmetries of difference equations, discrete geometry, among others. The special issue begins with four review papers: Integrable models in nonlinear optics and soliton solutions Degasperis [1] reviews integrable models in nonlinear optics. He presents a number of approximate models which are integrable and illustrates the links between the mathematical and applicative aspects of the theory of integrable dynamical systems. In particular he discusses the recent impact of boomeronic-type wave equations on applications arising in the context of the resonant interaction of three waves. Hamiltonian PDEs: deformations, integrability, solutions Dubrovin [2] presents classification results for systems of nonlinear Hamiltonian partial differential equations (PDEs) in one spatial dimension. In particular he uses a perturbative approach to the theory of integrability of these systems and discusses their solutions. He conjectures universality of the critical behaviour for the solutions, where the notion of universality refers to asymptotic independence of the structure of solutions (at the point of gradient catastrophe) from the choice of generic initial data as well as from the choice of a generic PDE. KP solitons in shallow water Kodama [3] presents a survey of recent studies on soliton solutions of the Kadomtsev-Petviashvili (KP) equation. A large variety of exact soliton solutions of the KP equation are presented and classified. The study includes numerical analysis of the stability of the found solution as well as numerical simulations of the initial value problems which indicate that a certain class of initial waves approach asymptotically these exact solutions

Gmez-Ullate, David; Lombardo, Sara; Maas, Manuel; Mazzocco, Marta; Nijhoff, Frank; Sommacal, Matteo

2010-10-01

343

Surface preparation of hard ionic crystals by ultrahigh vacuum cleavage  

NASA Astrophysics Data System (ADS)

A complete procedure for the preparation of clean surfaces of especially hard ionic crystals by ultrahigh vacuum (UHV) cleavage is given and exemplified by the preparation of the (001) surface of single MgO crystals. All important tools that are needed for the preparation are explained in detail. We present a device that allows precise cleavages in UHV and show how it can be easily integrated into an existing UHV system equipped with a linear manipulator. Cleaving ionic crystals produces charges on and below the fresh surface, which strongly hamper experiments like dynamic scanning force microscopy. In the case of MgO imaging is mostly impossible right after cleavage. We show that it is sufficient to anneal MgO crystals at temperatures higher than 350 C in order to reduce a large part of the charges. For the annealing, an UHV oven is used that can be annealed up to 550 C without leaving the upper 10-10 mbar pressure region. Our techniques can be used in principle also for softer ionic crystals such as KBr, KCl, NaCl, and for other hard materials such as semiconducting ZnO.

Barth, Clemens; Claeys, Christian; Henry, Claude R.

2005-08-01

344

Vacuum Packaging for Microelectromechanical Systems (MEMS).  

National Technical Information Service (NTIS)

The Vacuum Packaging for MEMS Program focused on the development of an integrated set of packaging technologies which in totality provide a low cost, high volume product-neutral vacuum packaging capability which addresses all MEMS vacuum packaging require...

T. Schimert R. Howe M. Schmidt S. Montague

2002-01-01

345

Characterization of textitM-plane GaN thin film grown on pre-annealing ?-LiGaO2 (100) substrate  

NASA Astrophysics Data System (ADS)

We used the plasma-assisted molecular-beam epitaxy to grow the M-plane GaN thin films on ?-lithium gallate, ?-LiGaO2, which had been annealed in vacuum and in air ambient. With the X-ray diffraction analysis, different azimuth angles (0^o and 90^o) were applied in ?-2? scanning measurement. The signal of M-plane GaN was deviated from the normal value to be -0.147 in vacuum and -0.048 in air ambient, which showed that LGO substrate pre-annealed in air can reduce the compressive strains in the growing sample effectively. The same result was confirmed by the Raman scattering analysis. It showed that the sample pre-annealed in vacuum had E2 phonon frequency which was shifted to 574.35 cm-1 due to the stress and the sample pre-annealed in air had E2 phonon frequency which was shifted only to 568.73 cm-1. In conclusion, thermal annealing of ?-LiGaO2 substrate in air can improve the quality of growing M-plane GaN and effectively suppresses the formation of lithium-rich surface for the growth M-plane GaN thin films on ?-LiGaO2 substrate.

Tsai, Cheng-Da; Shih, Cheng-Hung; Lo, Ikai; Wang, Ying-Chieh; Yang, Chen-Chi; Lin, Yu-Chiao; Chou, Mitch M. C.

2013-03-01

346

Thermoluminescent response of LiF (TLD100) to 5-30 keV electrons and the effect of annealing in various atmospheres  

Microsoft Academic Search

The response of single crystal and extruded ribbons of TLD-100 was investigated. If annealing is done in a vacuum, the sensitivity of TLD-100 single crystals to these electrons and the resultant glow curve are essentially the same as when irradiations are carried out with 137Cs gamma rays. All discrepancies in sensitivity can then be accounted for by the higher LET

J B Lasky; P R Moran

1977-01-01

347

Precooler Ring Vacuum System  

SciTech Connect

The precooler vacuum system, as proposed by FNAL, is based on a suitable modification of the existing Electron Cooling Ring System. Because of the magnetic cycle of the bending magnets, distributed ion pumping, as exists in the Electron Cooling Ring, is not applicable. Instead, the proposed pumping will be done with commercial appendage ion pumps mounted approximately every two meters around the circumference of the ring. The loss of effective pumping speed and non-uniformity of system pressure with appendage pumps may not be major considerations but the large number required does effect experimental and analytical equipment placement considerations. There is a distributed pumping technique available which: (1) is not affected by the magnetic cycle of the bending magnets; (2) will provide a minimum of four times the hydrogen pumping speed of the proposed appendage ion pumps; (3) will require no power during pumping after the strip is activated; (4) will provide the heat source for bakeout; (5) is easily replaceable; and (6) can be purchased, installed, and operated at a generous economic advantage over the presently proposed ion pumped system. The pumping technique referred to is non-evaporable gettering with ST101 Zr/Al pumping strip. A technical description of this pumping strip is given on Data Sheet 1 and 2 attached to this report.

Moenich, J.

1980-10-02

348

Compact vacuum insulation  

DOEpatents

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

Benson, D.K.; Potter, T.F.

1992-10-27

349

Compact vacuum insulation  

DOEpatents

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01

350

NCSX Vacuum Vessel Fabrication  

SciTech Connect

The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in conjunction with the Oak Ridge National Laboratory (ORNL). The goal of this experiment is to develop a device which has the steady state properties of a traditional stellarator along with the high performance characteristics of a tokamak. A key element of this device is its highly shaped Inconel 625 vacuum vessel. This paper describes the manufacturing of the vessel. The vessel is being fabricated by Major Tool and Machine, Inc. (MTM) in three identical 120 vessel segments, corresponding to the three NCSX field periods, in order to accommodate assembly of the device. The port extensions are welded on, leak checked, cut off within 1" of the vessel surface at MTM and then reattached at PPPL, to accommodate assembly of the close-fitting modular coils that surround the vessel. The 120 vessel segments are formed by welding two 60 segments together. Each 60 segment is fabricated by welding ten press-formed panels together over a collapsible welding fixture which is needed to precisely position the panels. The vessel is joined at assembly by welding via custom machined 8" (20.3 cm) wide spacer "spool pieces." The vessel must have a total leak rate less than 5 X 10-6 t-l/s, magnetic permeability less than 1.02?, and its contours must be within 0.188" (4.76 mm). It is scheduled for completion in January 2006.

Viola, M. E.; Brown, T.; Heitzenroeder, P.; Malinowski, F.; Reiersen, W.; Sutton, L.; Goranson, P.; Nelson, B.; Cole, M.; Manuel, M.; McCorkle, D.

2005-10-07

351

Vacuum plasma spray coating  

NASA Technical Reports Server (NTRS)

Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

Holmes, Richard R.; Mckechnie, Timothy N.

1989-01-01

352

Vacuum applications of metal foams  

NASA Technical Reports Server (NTRS)

Several vacuum applications of copper foams in the density range 2-5% and pore sizes of 0.5-0.7 mm are discussed, such as a foreline hydrocarbon trap in a mechanical vacuum pump, a molecular-flow resistor, a diffuser, and a water injector. Other suggested applications include the use of foam copper in the form of an externally heated plug to remove traces of oxygen from inert gases bled into a vacuum system through a stainless steel line and the use of the porous surface for minimizing release of secondary electrons from electrodes in the path of charged particle beams.

Kendall, B. R. F.

1980-01-01

353

Vacuum Function Operation and Systems  

NSDL National Science Digital Library

The understanding of vacuum function and systems is essential for students and employees working within the micro- and nanofabrication industry. This presentation/webinar highlights the use, construction, and examples of current vacuum technology systems today. Prepared by WHO, of the Nanotechnology Applications and Career Knowledge (NACK), a National ATE Center, this presentation provides material presented from the instructor/engineer viewpoint. Discussions include vacuum pump function, gauge use and ranges, applicable design considerations, as well as insight on cost and equipment training methodologies that have been utilized by the NACK Center. This site requires a free log-in to access.

2009-10-06

354

Vacuum applications of metal foams  

NASA Astrophysics Data System (ADS)

Several vacuum applications of copper foams in the density range 2-5% and pore sizes of 0.5-0.7 mm are discussed, such as a foreline hydrocarbon trap in a mechanical vacuum pump, a molecular-flow resistor, a diffuser, and a water injector. Other suggested applications include the use of foam copper in the form of an externally heated plug to remove traces of oxygen from inert gases bled into a vacuum system through a stainless steel line and the use of the porous surface for minimizing release of secondary electrons from electrodes in the path of charged particle beams.

Kendall, B. R. F.

1980-12-01

355

Ordering Phenomena in Undercooled Alloys  

SciTech Connect

Much of the work performed under this grant was devoted to using modern ideas in kinetics to understand atom movements in metallic alloys far from thermodynamic equilibrium. Kinetics arguments were based explicitly on the vacancy mechanism for atom movements. The emphasis was on how individual atom movements are influenced by the local chemical environment of the moving atom, and how atom movements cause changes in the local chemical environments. The author formulated a kinetic master equation method to treat atom movements on a crystal lattice with a vacancy mechanism. Some of these analyses [3,10,16] are as detailed as any treatment of the statistical kinetics of atom movements in crystalline alloys. Three results came from this work. Chronologically they were (1) A recognition that tracking time dependencies is not necessarily the best way to study kinetic phenomena. If multiple order parameters can be measured in a material, the ''kinetic path'' through the space spanned by these order parameters maybe just as informative about the chemical factors that affect atom movements [2,3,5-7,9-11,14-16,18,19,21,23,24,26,36,37]. (2) Kinetic paths need not follow the steepest gradient of the free energy function (this should be well-known), and for alloys far from equilibrium the free energy function can be almost useless in describing kinetic behavior. This is why the third result surprised me. (3) In cluster approximations with multiple order parameters, saddle points are common features of free energy functions. Interestingly, kinetic processes stall or change time scale when the kinetic path approaches a state at a saddle point in the free energy function, even though these states exist far from thermodynamic equilibrium. The author calls such a state a ''pseudostable'' (falsely stable) state [6,21,26]. I have also studied these phenomena by more ''exact'' Monte Carlo simulations. The kinetic paths showed features similar to those found in analytical theories. The author found that a microstructure with interfaces arranged in space as a periodic minimal surface is a probably an alloy at a saddle point in its free energy function [21,26,37].

Fultz, Brent

1997-07-17

356

Influence of in-situ annealing ambient on p-type conduction in dual ion beam sputtered Sb-doped ZnO thin films  

SciTech Connect

Sb-doped ZnO (SZO) films were deposited on c-plane sapphire substrates by dual ion beam sputtering deposition system and subsequently annealed in-situ in vacuum and in various proportions of O{sub 2}/(O{sub 2} + N{sub 2})% from 0% (N{sub 2}) to 100% (O{sub 2}). Hall measurements established all SZO films were p-type, as was also confirmed by typical diode-like rectifying current-voltage characteristics from p-ZnO/n-ZnO homojunction. SZO films annealed in O{sub 2} ambient exhibited higher hole concentration as compared with films annealed in vacuum or N{sub 2} ambient. X-ray photoelectron spectroscopic analysis confirmed that Sb{sup 5+} states were more preferable in comparison to Sb{sup 3+} states for acceptor-like Sb{sub Zn}-2V{sub Zn} complex formation in SZO films.

Pandey, Sushil Kumar; Kumar Pandey, Saurabh; Awasthi, Vishnu; Mukherjee, Shaibal [Hybrid Nanodevice Research Group (HNRG), Discipline of Electrical Engineering, Indian Institute of Technology, Indore 453441 (India)] [Hybrid Nanodevice Research Group (HNRG), Discipline of Electrical Engineering, Indian Institute of Technology, Indore 453441 (India); Gupta, M.; Deshpande, U. P. [University Grants Commission Department of Atomic Energy (UGC DAE) Consortium for Scientific Research, Indore (India)] [University Grants Commission Department of Atomic Energy (UGC DAE) Consortium for Scientific Research, Indore (India)

2013-08-12

357

Influence of in-situ annealing ambient on p-type conduction in dual ion beam sputtered Sb-doped ZnO thin films  

NASA Astrophysics Data System (ADS)

Sb-doped ZnO (SZO) films were deposited on c-plane sapphire substrates by dual ion beam sputtering deposition system and subsequently annealed in-situ in vacuum and in various proportions of O2/(O2 + N2)% from 0% (N2) to 100% (O2). Hall measurements established all SZO films were p-type, as was also confirmed by typical diode-like rectifying current-voltage characteristics from p-ZnO/n-ZnO homojunction. SZO films annealed in O2 ambient exhibited higher hole concentration as compared with films annealed in vacuum or N2 ambient. X-ray photoelectron spectroscopic analysis confirmed that Sb5+ states were more preferable in comparison to Sb3+ states for acceptor-like SbZn-2VZn complex formation in SZO films.

Pandey, Sushil Kumar; Kumar Pandey, Saurabh; Awasthi, Vishnu; Gupta, M.; Deshpande, U. P.; Mukherjee, Shaibal

2013-08-01

358

Exchange-diffusion reactions in HfSiON during annealing studied by Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling  

NASA Astrophysics Data System (ADS)

HfSiON films deposited on Si (001) by reactive sputtering were submitted to rapid thermal annealing at 1000 C in vacuum, N2 and O2 atmospheres. The stability of the dielectric was evaluated by measuring the atomic transport and exchange of the chemical species, using Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling. Annealing in O2 ambient reduced the N concentration mainly from near-surface regions where oxygen was incorporated in comparable amounts. Vacuum annealing, on the other hand, induced N loss preferentially from the Si/dielectric interface and O loss preferentially from near-surface regions. The results are explained in terms of exchange-diffusion reactions occurring in the HfSiON.

Miotti, L.; Bastos, K. P.; Soares, G. V.; Driemeier, C.; Pezzi, R. P.; Morais, J.; Baumvol, I. J. R.; Rotondaro, A. L. P.; Visokay, M. R.; Chambers, J. J.; Quevedo-Lopez, M.; Colombo, L.

2004-11-01

359

A Review of Maintenance of Vacuum inside Vacuum Insulation Panels  

Microsoft Academic Search

The growing concerns over global energy crisis and the phasing out of polyurethane foams blown with CFC-11, which has high Ozone Depletion Potential(ODP), have pushed thermal insulation technology to improve its efficiency. Vacuum Insulation Panel(VIP) has been regarded as a super thermal insulation material with a thermal resistance of about 5-10 times higher than conventional thermal insulation. Appropriate vacuum in

Chun Guang Yang; Lie Xu

2010-01-01

360

Changes in phase composition of ZrFeV getter after hydriding and vacuum dehydriding cycles  

Microsoft Academic Search

The stability and phase composition of the commercial non-evaporable getter SAES St 707 (70% Zr, 24.6% V, and 5.4% Fe) during hydriding and vacuum dehydriding cycles were investigated. Structure and phase composition were studied using X-ray diffraction (XRD) with Co K? and 57Fe Mssbauer spectroscopy (MS). The samples were hydrided during annealing in pure hydrogen at 550C for 15min and

P. Roupcov; O. Schneeweiss

2010-01-01

361

Data acquisition and simulation of natural phenomena  

Microsoft Academic Search

Virtual natural phenomena obtained through mathematical-physical modeling and simulation as well as graphics emulation can\\u000a meet the users requirements for sensory experiences to a certain extent but they can hardly have the same accurate physical\\u000a consistency as real natural phenomena. The technology for data acquisition and natural phenomena simulation can enable us\\u000a to obtain multi-dimensional and multi-modal data directly from

QinPing Zhao

2011-01-01

362

Solvothermal annealing of block copolymer thin films.  

PubMed

A two-stage annealing process for block copolymer films was introduced consisting of a solvent vapor exposure followed by a thermal cycle. By heating the film but not the chamber, changes in the ambient vapor pressure of the solvent were avoided. Films of block copolymers and homopolymers showed transient nonmonotonic swelling behavior immediately after solvent exposure that was dependent on how the thin film was cast before the anneal. Thermal cycling of the solvent-swelled block copolymer films during the solvent vapor anneal (SVA) caused the films to deswell in 1-10 s and produced well-ordered microdomains in templated 45.5 and 51.5 kg/mol polystyrene-block-polydimethylsiloxane films annealed in toluene and n-heptane vapors for total process times of 30 s to 5 min. PMID:24083573

Gotrik, Kevin W; Ross, C A

2013-11-13

363

Radiation damage and annealing of scintillating glasses  

Microsoft Academic Search

Measurements of the radiation hardness, of cerium and terbium doped scintillating glasses, are reported in this work. Annealing tests have demonstrated the efficacy of violet-blue light in the repairing of radiation damage.

P. Pavan; G. Zanella; R. Zannoni; P. Polato

1991-01-01

364

Biofilaments as annealed semi-flexible copolymers  

NASA Astrophysics Data System (ADS)

In many in vivo or in vitro situations, biofilaments manifest some annealed heterogeneity and should be considered as annealed random copolymers. The building blocks of the filaments differ from each other, for example, by the internal structure of the monomer, by the presence of some adsorbed species or by the curvature. Based on the copolymer concept, we embed the description of these systems in a common formalism. We demonstrate how the annealed heterogeneous nature of the filament is reflected by statistical correlations like the tangent-tangent correlation function or the cyclization probability. Our results show that annealed filaments adapt cooperatively to external constraints. This could contribute to explain anomalous elasticity manifested by biofilaments.

Fierling, Julien; Mohrbach, Herv; Kulic, Igor; Lee, Nam-Kyung; Johner, Albert

2014-06-01

365

Elements of Tempering, Normalizing, and Annealing.  

National Technical Information Service (NTIS)

Explains how steel is tempered, how the structure, toughness, and hardness of plain carbon steel changes at progressive tempering stages, and how steel is normalized and annealed. Describes the results.

1994-01-01

366

Enhanced performance of SubPC/C60 solar cells by annealing and modifying surface morphology.  

PubMed

The performance effect of organic solar cells with subphthalocyanine (SubPC)/fullerene (C60) bilayer was investigated with thermal treatment while changing the vacuum deposition rate of SubPC. The thermal annealing at 100 degrees C increases the optical absorption intensity of SubPC film at the spectral range of 550-630 nm. The X-ray diffraction (XRD) patterns indicates that the thermally annealed film formed the much-ordered morphology, as compared to the non-annealed film. Consequently, thermally treated solar cell exhibited almost 10% higher power conversion efficiency (PCE) compared to the non-annealed device. The fill factor (FF) and PCE of the devices were increased as the deposition rate of SubPC was increased up to 5 A/s and then saturated at higher deposition rates (> 5 A/s). The surface roughness of SubPC films, measured with an atomic force microscope, increased from 1.1 to 5 nm as the deposition rate increased from 1 to 7 A/s. These results imply that rough surface increases the interfacial area between SubPC and C60 and thereby improves the separation of photogenerated electron and hole pairs at the SubPC/C60 interface. PMID:22966642

Kim, Jun Young; Kwak, Jeonghun; Noh, Seunguk; Lee, Changhee

2012-07-01

367

Nonepileptic motor phenomena in the neonate  

PubMed Central

The newborn infant is prone to clinical motor phenomena that are not epileptic in nature. These include tremors, jitteriness, various forms of myoclonus and brainstem release phenomena. They are frequently misdiagnosed as seizures, resulting in unnecessary investigations and treatment with anticonvulsants, which have potentially harmful side effects. Unfortunately, there is a paucity of literature about many of these phenomena in the newborn, and some of the major textbooks refer to these events as nonepileptic seizures, leading to further confusion for the practitioner. The present paper aims to review these phenomena with special emphasis on differentiating them from epileptic seizures, and offers information on treatment and prognosis wherever possible.

Huntsman, Richard James; Lowry, Noel John; Sankaran, Koravangattu

2008-01-01

368

Alloying behavior at the AuGeNi\\/GaSb interface: Photoemission studies of the effects of annealing temperature  

Microsoft Academic Search

An ultra-thin AuGeNi alloy (84%\\/12%\\/4% by weight) overlayer of 5 nm was evaporated onto Te-doped n-type (100) oriented GaSb substrates. Samples were annealed in ultra-high vacuum (UHV), with a base pressure of 10-10 Torr at either 300C, 500C, or 700C for 12 h. The reacted interface was then revealed by Ar ion sputter-depth profiling. The highest percentage of Ge in

W. S. Tse; R. H. Chen; C. S. Ares Fang; J. R. Chen

1992-01-01

369

The effects of composition and annealing conditions on the stability of columbium (niobium)-treated low-carbon steels  

Microsoft Academic Search

The effects of composition and annealing conditions on the yielding behavior of vacuum melted, columbium(niobium) -treated,\\u000a low-carbon steels were investigated. Additions of columbium were found to result in stabilization,i.e. freedom from inhomogeneous yielding or Lders strain in the as-recrystallized condition. Stabilization is accounted for\\u000a by considering the role of columbium as a carbide former, thereby reducing the carbon content in

R. E. Hook; J. A. Elias

1972-01-01

370

The effects of composition and annealing conditions on the stability of columbium (niobium)-treated low-carbon steels  

Microsoft Academic Search

The effects of composition and annealing conditions on the yielding behavior of vacuum melted, columbium(niobium) -treated, low-carbon steels were investigated. Additions of columbium were found to result in stabilization, i.e. freedom from inhomogeneous yielding or Lder's strain in the as-recrystallized condition. Stabilization is accounted for by considering the role of columbium as a carbide former, thereby reducing the carbon content

R. E. Hook; J. A. Elias

1972-01-01

371

Improvement of M-plane GaN thin film grown on pre-annealing ?-LiGaO 2 (100) substrate  

NASA Astrophysics Data System (ADS)

In this paper, we report the growth of M-plane GaN thin films on LiGaO 2 (100) substrates pre-annealed in vacuum and in air ambient. The surface of M-plane GaN film grown on the LiGaO 2 (100) substrate pre-annealed in air ambient was significantly improved. X-ray diffraction data showed that the M-plane GaN thin film grown on the LiGaO 2 (100) substrate pre-annealed in air ambient has better crystal quality than that grown on the LiGaO 2 (100) substrate pre-annealed in vacuum. In addition, the strain generated between GaN thin film and LiGaO 2 substrate was relaxed when the GaN thin film grew on the LiGaO 2 substrate pre-annealed in air ambient. It revealed that the thermal annealing LiGaO 2 substrate in air ambient can suppress the formation of lithium-rich surface effectively, and then one can grow a high quality M-plane GaN thin film on the LiGaO 2 substrate.

Shih, Cheng-Hung; Lo, Ikai; Wang, Ying-Chieh; Yang, Chen-Chi; Chou, Mitch M. C.

2012-02-01

372

Monitoring of Transient Lunar Phenomena  

NASA Astrophysics Data System (ADS)

Transient Lunar Phenomena (TLPs) are described as short-lived changes in the brightness of areas on the face of the Moon. TLP research is characterized by the inability to substantiate, reproduce, and verify findings. Our current research includes the analysis of lunar images taken with two Santa Barbara Instrument Group (SBIG) ST8-E CCD cameras mounted on two 0.36m Celestron telescopes. On one telescope, we are using a sodium filter, and on the other an H-alpha filter, imaging approximately one-third of the lunar surface. We are focusing on two regions: Hyginus and Ina. Ina is of particular interest because it shows evidence of recent activity (Schultz, P., Staid, M., Pieters, C. Nature, Volume 444, Issue 7116, pp. 184-186, 2006). A total of over 50,000 images have been obtained over approximately 35 nights and visually analyzed to search for changes. As of March, 2014, no evidence of TLPs has been found. We are currently developing a Matlab program to do image analysis to detect TLPs that might not be apparent by visual inspection alone.

Barker, Timothy; Farber, Ryan; Ahrendts, Gary

2014-06-01

373

WESF natural phenomena hazards survey  

SciTech Connect

A team of engineers conducted a systematic natural hazards phenomena (NPH) survey for the 225-B Waste Encapsulation and Storage Facility (WESF). The survey is an assessment of the existing design documentation to serve as the structural design basis for WESF, and the Interim Safety Basis (ISB). The lateral force resisting systems for the 225-B building structures, and the anchorages for the WESF safety related systems were evaluated. The original seismic and other design analyses were technically reviewed. Engineering judgment assessments were made of the probability of NPH survival, including seismic, for the 225-B structures and WESF safety systems. The method for the survey is based on the experience of the investigating engineers,and documented earthquake experience (expected response) data.The survey uses knowledge on NPH performance and engineering experience to determine the WESF strengths for NPH resistance, and uncover possible weak links. The survey, in general, concludes that the 225-B structures and WESF safety systems are designed and constructed commensurate with the current Hanford Site design criteria.

Wagenblast, G.R., Westinghouse Hanford

1996-07-01

374

Review - Axial compressor stall phenomena  

NASA Technical Reports Server (NTRS)

Stall in compressors can be associated with the initiation of several types of fluid dynamic instabilities. These instabilities and the different phenomena, surge and rotating stall, which result from them, are discussed in this paper. Assessment is made of the various methods of predicting the onset of compressor and/or compression system instability, such as empirical correlations, linearized stability analyses, and numerical unsteady flow calculation procedures. Factors which affect the compressor stall point, in particular inlet flow distortion, are reviewed, and the techniques which are used to predict the loss in stall margin due to these factors are described. The influence of rotor casing treatment (grooves) on increasing compressor flow range is examined. Compressor and compression system behavior subsequent to the onset of stall is surveyed, with particular reference to the problem of engine recovery from a stalled condition. The distinction between surge and rotating stall is emphasized because of the very different consequences on recoverability. The structure of the compressor flow field during rotating stall is examined, and the prediction of compressor performance in rotating stall, including stall/unstall hysteresis, is described.

Greitzer, E. M.

1980-01-01

375

Photoinduced phenomena in polysilane films  

NASA Astrophysics Data System (ADS)

The photoinduced phenomena involving the photoscission of (sigma) bonds and photocreation of electronic defects have been studied systematically in films of (MeSiPh)n, (n- Hex2Si)n, (c-HeSiMe)n and (n-pentyl2Si)n as different polysilanes with and without phenyl substituents. The results have revealed the followings. A photoscission model established for (MeSiPh)n, where the photoscission cross-section is larger for longer segments and the reaction is thermally activated with the activation energies being distributed in a shape given by a combination with two exponential functions, is consistent with the processes in other polysilanes. The photoscission of (sigma) bonds creates defects to decrease the photoluminescence for polysilanes with phenyl substituents and some centers to enhance the photoluminescence for (c-HexSiMe)n and (n- pentyl2Si)n. The photoscission of (sigma) bonds occurs preferably at edges of the segments in (c-Hex2Si)n and at the inside of the segments for other three polysilanes. The orientation of (MeSiPh)n is effective to decrease the photoscission cross-section.

Nakayama, Yoshikazu; Inagi, Hiroyuki; Fujii, Tatsuo; Pan, Lujun

2000-11-01

376

Quantum phenomena in semiconductor structures  

NASA Astrophysics Data System (ADS)

The research investigated the electronic properties of small semiconductor devices where transport is dominated or affected by quantum phenomena. Topics investigated included small silicon MOS transistors. Here it is shown that large, intrinsic, stresses affect transport in the two dimensional inversion layer. As the stress is at the edge of the device, it is not significant for larger structures. The electron-phonon interaction in epitaxial layers of GaAs has been investigated using Schottky gate FETs (MESFETs). It is shown that the nature and interpretation of magnetophonon oscillations is strongly affected by the geometry of the sample. Studies of small samples were extended to one dimensional GaAs-AlGaAs heterojunctions where it was shown that varying the width at low temperatures resulted in large random conductance fluctuations. These were fitted to the appropriate theory. Quantum corrections to the conductivity and Hall effect were investigated in a range of III-V semiconductors, and, in a new development, a technique of electrostatic squeezing was developed to investigate quantum interference in a ring of electron gas in a GaAs-AlGaAs heterojunction. A description is given of measurements and analysis of electronic transport in MBE grown InSb.

Pepper, M.

1988-12-01

377

Annealing behavior of electroplated permalloy thin films  

Microsoft Academic Search

The isochronal annealing behavior of electroplated 1.2 ?m Ni-Fe thin films containing nominally 80 wt% Ni, in the temperature\\u000a range from 373? to 773?K, and with a magnetic field parallel to the easy axis of the films, was investigated through measurements\\u000a of the films structural, magnetic and electrical properties. The effects of annealing could be described in terms of two

R. L. Anderson; A. Gangulee; L. T. Romankiw

1973-01-01

378

Quantum Annealing and Related Optimization Methods  

NASA Astrophysics Data System (ADS)

Quantum annealing employs quantum fluctuations in frustrated systems or networks to anneal the system down to its ground state, or more generally to its so-called minimum cost state. Often this procedure turns out to be more effective, in multivariable optimization problems, than its classical counterpart utilizing tunable thermal fluctuations. This volume is divided into three parts. Part I is an extensive tutorial introduction familiarizing the reader with the background material necessary to follow the core of the book.

Das, Arnab; Chakrabarti, Bikas K.

379

Mirowave annealing of silicon nitride materials  

SciTech Connect

Dense silicon nitride-based ceramics were microwave annealed to determine if microwave heating offers advantages over conventional heating for the enhancement of the high temperature creep resistance. Gas pressure sintered silicon nitride (GPS-SN) and sintered reaction-bonded silicon nitride (SRBSN) were heated in microwave or graphite element furnaces at 1150{degrees}C and 1600{degrees}C. Annealed materials were characterized for the room and high temperature flexural strengths, room temperature fracture toughness values, and high temperature creep properties. In addition, SEM analyses were performed to study grain growth and other microstructural changes. The results of this study showed that both types of furnace anneals at 1150{degrees}C lowered the room temperature strength and toughness values of both SRBSN and GPS-SN materials; however, the anneal treatments at 1600{degrees}C had little effect on the room temperature properties. Both the SRBSN and GPS-SN control and annealed samples had reduced high temperature fast fracture strengths, when compared to the room temperature strengths. Creep tests at 1200{degrees}C indicated that both the SRBSN and the GPS-SN materials that were annealed by microwave heating at I 150{degrees}C for 20 h showed enhanced creep resistance, when compared to unheated controls and conventionally heated materials. No qualitative differences were seen in the microstructures of the SRBSN and the GPS-SN materials which could account for the differences in the creep properties of the annealed materials. Additional experimental work is in progress to further understand the mechanisms for the enhanced creep properties of silicon nitride materials annealed by microwave heating.

Kiggans, J.O. Jr.; Montgomery, F.C.; Tiegs, T.N. [and others] [and others

1997-08-01

380

Magnetic induced heating for ferritic metal annealing  

SciTech Connect

A method is described for annealing the wall of a nuclear reactor vessel, including, positioning an electromagnet within a vertically positioned nuclear reactor vessel by lowering the electromagnet into the vessel, supplying power to the electromagnet to generate substantially uniform heat in the vessel wall, maintaining the power to the electromagnet for a predetermined length of time which will anneal the vessel wall, and removing the electromagnet.

De Witt, G.L.; Huber, D.J.

1987-03-24

381

Annealed CVD molybdenum thin film surface  

DOEpatents

Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

Carver, Gary E. (Tucson, AZ); Seraphin, Bernhard O. (Tucson, AZ)

1984-01-01

382

High pressure annealing of CVD diamond films  

Microsoft Academic Search

CVD diamond films were annealed from 600 to 1900 C at 7.7 GPa in a toroidal high pressure (HP) apparatus, always inside the diamond-phase stability region. The annealed films were analyzed by Raman and infrared (IR) spectroscopy and the results showed that the diamond grains remained stable while the non-diamond carbon phases and impurities, responsible for the intricate film structure,

N. M. Balzaretti; J. A. H. da Jornada

2003-01-01

383

Investigation of Ni/Ta contacts on 4H silicon carbide upon thermal annealing  

NASA Astrophysics Data System (ADS)

Nickel and Tantalum thin films with 3:5 thickness ratios were deposited in succession onto 4H-SiC substrate at room temperature. The samples were then heated in situ in vacuum at 650, 800 or 950 C for 30 min. Glancing angle X-ray diffraction (XRD), Auger electron spectroscopy (AES) and current-voltage ( I- V) technique were used for characterising the interfacial reactions and electrical properties. Amorphous Ni-Ta can be formed by solid-state reaction at 650 C. The minor dissolved Ni in the Ta metal promotes the reaction between Ta and SiC. With increasing annealing temperature up to 950 C, the dominant carbide changes from Ta 2C to TaC and a layer structure is developed. Electrical measurements show that ohmic contact is formed after annealing at or above 800 C.

Cao, Y.; Prez-Garca, S. A.; Nyborg, L.

2007-10-01

384

UV photoemission study of amorphous n-C 36H 74 films and their annealing process  

NASA Astrophysics Data System (ADS)

Amorphous films of hexatriacontane n-C 36H 74 were prepared by vacuum evaporation on low-temperature substrates (? 80 K), and their electronic structure including the change at annealing was studied by UV photoemission spectroscopy. The spectra of as deposited films were similar to those of molten state, but indicate a smaller degree of disorder. Upon annealing, the spectra changed drastically, reflecting the change of unoccupied states, with sharp change at ? 268 K corresponding to crystallization. The change was discussed with reference to reported structural studies by vibrational spectroscopies. The results show that the appearance of fine structures in unoccupied states requires not only extended (all-trans) chains but also regular intermolecular arrangements.

Seki, Kazuhiko; Ueno, Nobuo; Inokuchi, Hiroo

1994-05-01

385

Long-term microstructural stability of oxide-dispersion strengthened Eurofer steel annealed at 800 C  

NASA Astrophysics Data System (ADS)

Oxide-dispersion strengthened ferritic martensitic steels such as ODS-Eurofer grade are good candidates for structural applications in future fusion power reactors. Long-term annealing treatments in vacuum were carried out in cold-rolled samples (80% reduction in thickness) from 1 h up to 4320 h (6 months) at 800 C, i.e. the maximum temperature in the ferritic phase field, to follow its softening behavior. The microstructural stability of this steel was mapped using several characterization techniques including scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, Vickers microhardness testing, X-ray diffraction texture measurements, low-temperature electrical resistivity, and magnetic coercive field measurements. ODS-Eurofer steel displays good microstructural stability. Discontinuous recrystallization occurs at the early stages of annealing resulting in a low volume fraction of recrystallized grains. Extended recovery is the predominant softening mechanism at this temperature for longer times.

Zilnyk, K. D.; Sandim, H. R. Z.; Bolmaro, R. E.; Lindau, R.; Mslang, A.; Kostka, A.; Raabe, D.

2014-05-01

386

Effects of annealing process on characteristics of fully transparent zinc tin oxide thin-film transistor  

NASA Astrophysics Data System (ADS)

Annealing effect on the performance of fully transparent thin-film transistor (TTFT), in which zinc tin oxide (ZnSnO) is used as the channel material and SiO2 as the gate insulator, is investigated. The ZnSnO active layer is deposited by radio frequency magnetron sputtering while a SiO2 gate insulator is formed by plasma-enhanced chemical vapor deposition. The saturation field-effect mobility and on/off ratio of the TTFT are improved by low temperature annealing in vacuum. Maximum saturation field-effect mobility and on/off ratio of 56.2 cm2/(Vs) and 3 105 are obtained, respectively. The transfer characteristics of the ZnSnO TFT are simulated using an analytical model and good agreement between measured and the calculated transfer characteristics is demonstrated.

Chen, Yong-Yue; Wang, Xiong; Cai, Xi-Kun; Yuan, Zi-Jian; Zhu, Xia-Ming; Qiu, Dong-Jiang; Wu, Hui-Zhen

2014-02-01

387

Pollution prevention in vacuum processes  

SciTech Connect

The gaseous emissions from vacuum systems often contain volatile organic compounds (VOCs)--one or more of which may be regulated as Hazardous Air Pollutants (HAPs) under the 1990 Clean Air Act Amendments. Typically, regulated emission sources will require greater than 98% control of using an end-of-pipe abatement or recovery technology. VOCs from vacuum generation are expensive to control and increase the investment and operating cost of the vacuum system. When noncondensibles or inerts are present, the amount of VOCs emitted to the environment will increase dramatically. This article discusses approaches which process and project engineers can apply to reduce or eliminate vacuum system emissions. Actual case histories are included which reflect the range of solutions that are being applied.

Mulholland, K.L.; Dyer, J.A. [E.I. du Pont de Nemours and Co., Wilmington, DE (United States)] [E.I. du Pont de Nemours and Co., Wilmington, DE (United States)

1999-05-01

388

APS storage ring vacuum system  

SciTech Connect

The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs.

Niemann, R.C.; Benaroya, R.; Choi, M.; Dortwegt, R.J.; Goeppner, G.A.; Gonczy, J.; Krieger, C.; Howell, J.; Nielsen, R.W.; Roop, B.; Wehrle, R.B.

1990-01-01

389

Vacuum system pump down analysis  

SciTech Connect

My assignment on the SP-100 Vacuum Vessel Vacuum System Team was to perform a transient pump down analysis for the vacuum vessel that will house the SP-100 reactor during testing. Pump down time was calculated for air and helium. For all cases the proposed vacuum system will be able to pump down the vessel within the required time. The use of a larger rotary piston pump (DUO250) improves the pump down time by 35 minutes and therefore should be considered. The 6-inch duct for the roughing line is optimal, however, because all cases are well below the 24 hour time frame, the 4-inch duct is sufficient. The use of the single turbomolecular pump during pump down is sufficient. A pump down with helium in the vessel and a helium inleakage delays the time to achieve the base pressure marginally and is acceptable.

Rohrdanz, D.R.

1990-08-01

390

Simple vacuum pump exhaust filter  

Microsoft Academic Search

A simple vacuum pump exhaust filter based upon an automotive air cleaner has been constructed and tested. The major virtues of the filter system are ease of coupling to an external exhaust and the availability of filter elements.

Richard A. Forman; Harvey D. Kratz

1984-01-01

391

Alumina barrier for vacuum brazing  

NASA Technical Reports Server (NTRS)

Heating platens of vacuum-brazing press will not stick to workpiece if aluminum oxide "paper" is interposed. Paper does not disintegrate in press, will not contaminate braze alloy, and helps form smoothly contoured, regular fillet at brazed edges.

Beuyukian, C. S.

1980-01-01

392

Vacuum Outgassing of Various Materials.  

National Technical Information Service (NTIS)

A gas analytical system for measuring the evolved gases from materials during vacuum degassing is discussed. The outgassing data are based upon the throughput measurement and a computer-controlled quadrupole mass spectrometer allows the determination of r...

E. D. Erikson T. G. Beat D. D. Berger B. A. Frazier

1983-01-01

393

Effect of thermal annealing on structure and optical band gap of amorphous Se72Te25Sb3 thin films  

NASA Astrophysics Data System (ADS)

Thin films of a-Se72Te25Sb3 were prepared by vacuum evaporation technique in a base pressure of 10-6 Torr on to well cleaned glass substrate. a-Se72Te25Sb3 thin films were annealed at different temperatures below their crystallization temperatures for 2h. The structural analysis of the films has been investigated using X-ray diffraction technique. The optical band gap of as prepared and annealed films as a function of photon energy in the wavelength range 400-1100 nm has been studied. It has been found that the optical band gap decreases with increasing annealing temperatures in the present system.

Dwivedi, D. K.; Pathak, H. P.; Kumar, Vipin; Shukla, Nitesh

2014-04-01

394

Improved electron collection in fullerene via caesium iodide or carbonate by means of annealing in inverted organic solar cells  

NASA Astrophysics Data System (ADS)

Inverted organic photovoltaic cells (IOPVCs), based on the planar heterojunction C60/CuPc, were grown using MoO3 as anode buffer layer and CsI or Cs2CO3 as cathode buffer layer (CBL), the cathode being an ITO coated glass. Work functions, ?f, of treated cathode were estimated using the cyclic voltammetry method. It is shown that ?f of ITO covered with a Cs compounds is decreased. This decrease is amplified by the annealing. It is shown that the thermal deposition under vacuum of the CBL induces a partial decomposition of the caesium compounds. In parallel, the formation of a compound with the In of ITO is put in evidence. This reaction is amplified by annealing, which allows obtaining IOPVCs with improved efficiency. The optimum annealing conditions is 150 C for 5 min.

El Jouad, Zouhair; Louarn, Guy; Praveen, Thappily; Predeep, Padmanabhan; Cattin, Linda; Bernde, Jean-Christian; Addou, Mohammed; Morsli, Mustapha

2014-05-01

395

Control of KEKB vacuum system  

Microsoft Academic Search

In a vacuum system of the KEKB accelerator that is a two ring electron-positron collider, there are nearly 10,000 control points. A large number of vacuum related components should be controlled and\\/or monitored at the rings and the beam transport line from the linac. Those component hardwares are connected to their sub-interfaces such as ADC interfaced by devices of CAMAC,

S. Kato; K. Kanazawa; Y. Suetsugu; H. Hisamatsu; M. Shimamoto; M. Sato; M. Shirai; M. Takagi

2001-01-01

396

[Comparison vacuum extractor versus forceps].  

PubMed

The aim of the study was to search for objective criteria witch might help us to make a choice between obstetrical forceps and vacuum extractor in front of such a clinical situation. In that purpose, we realised a medline research to compare those two obstetrical instruments in term of advantages, disadvantages and specific complications. Vacuum extractor is the most used in the industrialized countries, learning seems to be quickest, time from decision to extraction a little bit longer than with forceps (Level II-2). Vacuum extractor is recommended in case of low presentation with transversal or posterior variety (Level III) or when no analgesia is available (Level III). Forceps are more successful than vacuum (Level II-1), are recommended in case of prematurity and complete anesthesia (Level III). Immediate maternal complications (cervical tear, vaginal and perineal laceration, use of episiotomy) are less frequent with vacuum extractor (Level II-1). Long term effects on the pelvic floor and the bladder continence are comparable with natural delivery for both forceps and vacuum (Level II-1) but anal incontinence is increased, especially with forceps (Level II-1). Benign immediate neonatal morbidity is comparable for both instruments, but there are some specific complications (Level II-1). Thus, cephalhaematomas and potentially dramatic extensive subgaleal haematomas (even rare), retinal haemorrhage are more frequent with the use of vacuum extractor (Level II-1). Facial nerve paralysis, skull fracture (even rare) are more frequent with forceps (Level II-2). Neonatal convulsions frequency is comparable with both instruments (Level II-2), such are middle and long term complications (Level II-3). Finally, failure of forceps extraction needs a caesarean section but there is no clear evidence in the literature for the sequential use of forceps after failure of vacuum (Level III). PMID:19268200

Schaal, J-P; Equy, V; Hoffman, P

2008-12-01

397

Vacuum Variable Medium Temperature Blackbody  

Microsoft Academic Search

This article describes the vacuum variable medium-temperature blackbody (VMTBB) constructed to serve as a highly stable reference\\u000a source with an aperture diameter of 20mm in the temperature range from 150C to 430C under medium-vacuum conditions (10?3 Pa) and in a reduced background environment (liquid-nitrogen-cooled shroud). The VMTBB was realized for the calibration facility\\u000a at the PTB in the field of

S. P. Morozova; N. A. Parfentiev; B. E. Lisiansky; U. A. Melenevsky; B. Gutschwager; C. Monte; J. Hollandt

2010-01-01

398

Extracting energies from the vacuum  

Microsoft Academic Search

We present and study a possible mechanism of extracting energies from the\\u000avacuum by external classical fields. Taking a constant magnetic field as an\\u000aexample, we discuss why and how the vacuum energy can be released in the\\u000acontext of quantum field theories. In addition, we give a theoretical\\u000acomputation showing how much vacuum energies can be released. The possibilities

She-Sheng Xue

2000-01-01

399

Edge conduction in vacuum glazing  

SciTech Connect

Vacuum glazing is a form of low-conductance double glazing using in internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

Simko, T.M.; Collins, R.E. [Sydney Univ., NSW (Australia). Dept. of Applied Physics; Beck, F.A.; Arasteh, D. [Lawrence Berkeley Lab., CA (United States)

1995-03-01

400

Cold cathode vacuum gauging system  

DOEpatents

A vacuum gauging system of the cold cathode type is provided for measuring the pressure of a plurality of separate vacuum systems, such as in a gas centrifuge cascade. Each casing is fitted with a gauge tube assembly which communicates with the vacuum system in the centrifuge casing. Each gauge tube contains an anode which may be in the form of a slender rod or wire hoop and a cathode which may be formed by the wall of the gauge tube. The tube is provided with an insulated high voltage connector to the anode which has a terminal for external connection outside the vacuum casing. The tube extends from the casing so that a portable magnet assembly may be inserted about the tube to provide a magnetic field in the area between the anode and cathode necessary for pressure measurements in a cold cathode-type vacuum gauge arrangement. The portable magnetic assembly is provided with a connector which engages the external high voltage terminal for providing power to the anode within in the gauge tube. Measurement is made in the same manner as the prior cold cathode gauges in that the current through the anode to the cathode is measured as an indication of the pressure. By providing the portable magnetic assembly, a considerable savings in cost, installation, and maintenance of vacuum gauges for pressure measurement in a gas centrifuge cascade is realizable.

Denny, Edward C. (Knoxville, TN)

2004-03-09

401

Effects of annealing, acid and alcoholic beverages on Fe1+yTe0.6Se0.4  

NASA Astrophysics Data System (ADS)

We have systematically investigated and compared different methods to induce superconductivity in the iron chalcogenide Fe1+yTe0.6Se0.4, including annealing in a vacuum, N2, O2 and I2 atmospheres and immersing samples into acid and alcoholic beverages. Vacuum and N2 annealing are proved to be ineffective in inducing superconductivity in a Fe1+yTe0.6Se0.4 single crystal. Annealing in O2 and I2 and immersion in acid and alcoholic beverages can induce superconductivity by oxidizing the excess Fe in the sample. Superconductivity in O2 annealed samples is of a bulk nature, while I2, acid and alcoholic beverages can only induce superconductivity near the surface. By comparing the different effects of O2, I2, acid and alcoholic beverages we propose a scenario to explain how the superconductivity is induced in the non-superconducting as-grown Fe1+yTe0.6Se0.4.

Sun, Y.; Taen, T.; Tsuchiya, Y.; Shi, Z. X.; Tamegai, T.

2013-01-01

402

Stability of mechanically alloyed vacancy ordered phase in Al70Cu15Ni15 alloy during annealing  

NASA Astrophysics Data System (ADS)

A nano ?3 vacancy-ordered phase in the Al-Cu-Ni alloy system has been synthesized with a composition close to Al70Cu15Ni15 by mechanical alloying a mixture of elemental powder in a high-energy ball mill by varying milling time from 10 to 100 hours. The stability of nano-crystalline ?3 vacancy-ordered phase has been studied under thermal annealing in vacuum as well as in air. The x-ray diffraction and transmission electron microscopy techniques were employed for characterization of the milled and annealed samples. The powder after 100 h of milling was found to contain mostly nano ?3 phase with the partial ordering, and with crystallite sizes in the range of 10-20 nm along with a lattice strain of ~0.67 %. The milled powder, after annealing in vacuum at 700 C for 60 h, revealed the formation of a strain-free and ordered ?3 phase with a crystallite size of 80 nm, indicating grain coarsening. It is interesting to note that the milled powder annealed in air at 700 C for 60 h showed the formation of (Cu,Ni)Al2O4 type spinel phase with the lattice parameter of 8.1 and the lattice strain as 0.52 %. The average grain size of spinel phase was found to be ~ 40 nm.

Prasad Yadav, Thakur; Krishna Mukhopadhyay, Nilay; Shyam Tiwari, Radhey; Nath Srivastava, Onkar

2010-04-01

403

Phenomena resulting from hypergolic contact  

NASA Astrophysics Data System (ADS)

Understanding hypergolic ignition is critical for the safe and successful operation of hypergolic engines. The complex coupling of physical and chemical processes during hypergolic ignition complicates analysis of the event. Presently, hypergolic ignition models cannot simulate liquid contact and mixing or liquid-phase chemical reactions, and rely on experimental results for validation. In some cases, chemical kinetics of hypergolic propellants and fluid dynamics of droplet collisions couple to produce unexpected phenomena. This research investigates contact between droplets and pools of liquid hypergolic propellants under various conditions in order to investigate these liquid-phase reactions and categorize the resulting interaction. During this experiment, 142 drop tests were performed to investigate phenomena associated with hypergolic contact of various propellants. A drop of fuel impacted a semi-ellipsoidal pool of oxidizer at varying impact velocities and impact geometries. The temperature, pressure, ambient atmosphere, and propellant quality were all controlled during the experiment, as these factors have been shown to influence hypergolic ignition delay. Three distinct types of impacts were identified: explosions, bounces, and splashes. The impact type was found to depend on the impact Weber number and impact angle. Splashes occurred above a critical Weber number of 250, regardless of impact angle. Explosions occurred for Weber numbers less than 250, and for impact angles less than seven degrees. If the impact angle was greater than seven degrees then the test resulted in a bounce. Literature related to explosions induced by hypergolic contact was reviewed. Explosions were observed to occur inconsistently, a feature that has never been addressed. Literature related to non-reactive splashing, bouncing, and coalescence was reviewed for insight into the explosion phenomenon. I propose that the dependence of impact angle on the transition between explosion and bounce impacts is partially responsible for the explosion inconsistency in literature. No explosions were observed for the alternative hypergolic propellants tested, which could be due to lower gas production rates or the absence of reactive intermediate species present in certain propellant chemistry. In either case, the fluid dynamics of the impact was consistent, but the chemical kinetics of the propellants were different, and presumably, the two did not couple as strongly. Based on the results, explosions appear to be a mixing driven process caused by the coupling between the fluid dynamics of the impact and the chemical kinetics of the propellants. Upon contact, the fuel drop merges with the oxidizer pool. Liquid-phase neutralization reactions produce enough heat to vaporize propellants, which then accumulate within a gas pocket inside the pool. Exothermic gas-phase reactions result in an explosion originating from within the propellant pool. In addition to investigation of the explosion phenomenon, high-speed videos were taken of the first microseconds of hypergolic contact to observe the liquid-phase chemical reactions in detail. The delay between contact and first gas production was measured to be between 20 and 200 microseconds for monomethylhydrazine and red fuming nitric acid. This delay provides insight into the speed of the liquid-phase chemical reactions, and has helped to calibrate liquid-based ignition models. This research has categorized different interactions resulting from hypergolic contact, and found that the impact Weber number and impact angle were the controlling parameters. I propose that slight changes in the impact angle went unobserved by previous researchers and were partially responsible for the explosion inconsistency in literature. Microsecond scale time delays were measured between contact and gas production and have been used to calibrate previously unknown rate constants of liquid-phase chemical reactions.

Forness, Jordan M.

404

Various post-annealing treatments on aluminum doped zinc oxide films fabricated by ion beam co-sputtering  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) films with the aluminum concentration of 1.5 at.% were fabricated by co-sputtering dual metallic targets, Al and Zn, under the oxygen partial pressure of 1.310-4 torr. The total pressure was kept at 2.3 10-4 torr during the deposition. The poly-crystalline structure, optical property and conductivity of the films were investigated by XRD, UV-VIS-IR spectrometer and Hall measurement, respectively. The more intense ZnO crystallinity of (002), larger grain size, smaller d-spacing and highest carrier concentrations were observed on the as deposited AZO film which had the lowest resistivity of 7.8 10-4 ?cm. Comparing the AZO films post-annealed in atmosphere, in vacuum and in hydrogen ambiance, the structures processed in vacuum and hydrogen ambiance remained the good ZnO crystallinity in the film resulting from the oxygen deficient state of the films after post annealing processes. The better thermal stability of resistivity was observed in the films post-annealed in hydrogen ambiance due to the formation of the shallow donor in the film. Furthermore, the resistivity increased as increasing the post-annealing temperature in atmosphere. When the as-deposited film were post-annealed at temperature of 400 C, the resistivity was about more than two orders of magnitude than that of the as-deposited film resulting from the decrease of the donor concentration and mobility in the AZO film. The variation of the carrier concentration in the AZO film also shifted the energy band gap. However, the average visible transmittance of all AZO films in this study was above 80 % regardless of the deposition and post-annealing conditions.

Hsu, Jin-Cherng; Chen, Yu-Yun; Chiang, Yueh-Sheng; Cho, Heng-Ying

2013-03-01

405

Annealing behavior of a modified 5083 aluminum alloy  

Microsoft Academic Search

The annealing behavior of a modified 5083 aluminum alloy was studied in the temperature range of 125375C with different holding times. The results shown that the annealing temperature was more sensitive to the mechanical and corrosion resistance properties compared with the annealing holding time. The mechanical and corrosion resistance properties depend on annealing treatment due to different dislocation configuration in

Shuangping Lin; Zuoren Nie; Hui Huang; Bolong Li

2010-01-01

406

An in-vacuum diffractometer for resonant elastic soft x-ray scattering  

NASA Astrophysics Data System (ADS)

We describe the design, construction, and performance of a 4-circle in-vacuum diffractometer for resonant elastic soft x-ray scattering. The diffractometer, installed on the resonant elastic and inelastic x-ray scattering beamline at the Canadian Light Source, includes 9 in-vacuum motions driven by in-vacuum stepper motors and operates in ultra-high vacuum at base pressure of 2 10-10 Torr. Cooling to a base temperature of 18 K is provided with a closed-cycle cryostat. The diffractometer includes a choice of 3 photon detectors: a photodiode, a channeltron, and a 2D sensitive channelplate detector. Along with variable slit and filter options, these detectors are suitable for studying a wide range of phenomena having both weak and strong diffraction signals. Example measurements of diffraction and reflectivity in Nd-doped (La,Sr)2CuO4 and thin film (Ga,Mn)As are shown.

Hawthorn, D. G.; He, F.; Venema, L.; Davis, H.; Achkar, A. J.; Zhang, J.; Sutarto, R.; Wadati, H.; Radi, A.; Wilson, T.; Wright, G.; Shen, K. M.; Geck, J.; Zhang, H.; Novk, V.; Sawatzky, G. A.

2011-07-01

407

Annealing of Amorphous Diamond-like Carbon Films Doped with Boron  

NASA Astrophysics Data System (ADS)

Amorphous hydrogenated diamond-like carbon (DLC) films have been prepared by the saddle-field glow discharge technique. The films were doped with boron from the gas phase during the deposition. Doping with boron has been proved to be controllable and electrically effective. The samples are p-type and exhibit a thermally activated conductivity in the temperature range 300-500 K. The data on hole concentration and mobility obtained from Hall effect measurements will be presented. Changes in transport properties of the samples resulted from annealing in vacuum at different temperatures will be discussed.

Sawyer, Shane; Allen, Tatiana; Gaspari, Franco; Zukotynski, Stefan

1999-11-01

408

Stochastic properties of partial-discharge phenomena  

Microsoft Academic Search

The author presents a bibliography and survey of the literature concerned with theory and measurement of the stochastic behavior of pulsating partial-discharge (PD) phenomena that can occur when insulation is subjected to electrical stress. The types of PD phenomena considered include AC and DC generated electron avalanches, pulsating positive and negative corona in gases, and PD that occur in liquid

R. J. Van Brunt

1991-01-01

409

Aging- and annealing-induced variations in Nb/Al-AlOx/Nb tunnel junction properties  

NASA Astrophysics Data System (ADS)

In this paper, we present studies of room temperature aging and annealing of Nb/Al-AlOx/Nb tunnel junctions with the size of 2-3 ?m2. We observed a noticeable drop of junction normal resistance Rn unusually combined with increase in subgap resistance Rj as a result of aging. Variation in both Rn and Rj are subject to the junction size effect. An effect of aging history on the junction degradation after consequent annealing was discovered. Discussion and interpretation of the observed phenomena are presented in terms of structural ordering and reconstruction in the AlOx layer, driven by diffusion flows enhanced due to stress relaxation processes in the Al layer interfacing the AlOx layer.

Pavolotsky, Alexey B.; Dochev, Dimitar; Belitsky, Victor

2011-01-01

410

EBSD coupled to SEM in situ annealing for assessing recrystallization and grain growth mechanisms in pure tantalum.  

PubMed

An in situ annealing stage has been developed in-house and integrated in the chamber of a Scanning Electron Microscope equipped with an Electron BackScattered Diffraction system. Based on the Joule effect, this device can reach the temperature of 1200C at heating rates up to 100C/s, avoiding microstructural evolutions during heating. A high-purity tantalum deformed sample has been annealed at variable temperature in the range 750C-1030C, and classical mechanisms of microstructural evolutions such as recrystallization and grain coarsening phenomena have been observed. Quantitative measurements of grain growth rates provide an estimate of the mean grain boundary mobility, which is consistent with the value estimated from physical parameters reported for that material. In situ annealing therefore appears to be suited for complementing bulk measurements at relatively high temperatures, in the context of recrystallization and grain growth in such a single-phase material. PMID:23521093

Kerisit, C; Log, R E; Jacomet, S; Llorca, V; Bozzolo, N

2013-06-01

411

Texture and Microstructure Evolution at the Metal-Vapour Interface During Transformation Annealing in a Mn and Al Alloyed Ultra Low Carbon Steel  

NASA Astrophysics Data System (ADS)

This paper investigates the evolution of texture and microstructure at the metal-vapour interface during transformation annealing in vacuum. Interrupted annealing experiments were carried out on cold rolled Mn, Al and Si alloyed ultra low carbon steels. The textures were characterized by X-ray diffraction and SEMEBSD techniques. The results show the variation in the surface texture components obtained after BCC recrystallisation and double ?-?-? transformation annealing. The recrystallisation texture consists mainly of a <111>//ND fibre, while the transformation texture at the surface exhibits a <100>//ND fibre in combination with components of the <110>//ND fibre. It was revealed that the latter specific surface texture was present in a monolayer of outer surface grains which were in direct contact with the vapour atmosphere. This observed phenomenon could be explained by considering the role of surface energy anisotropy occurring during phase transformation annealing.

Kestens, Leo A. I.; Gautam, Jai; Petrov, Roumen

412

Calculation of radiation-induced deformation in the ITER vacuum vessel  

NASA Astrophysics Data System (ADS)

Numerical calculation was carried out to evaluate the radiation induced deformation at the blanket side of the vacuum vessel (120C) and the rear portion of the blanket module (200C) in ITER. The calculation was performed for solution-annealed 316 stainless steel mainly at 110 -9 dpa/s and 100 MPa. Enhanced transient creep characteristic of the low temperature irradiation is evident at 120C. However, the total accumulated creep strain in the vacuum vessel is only below 0.01% for the lifetime irradiation so that serious consequence would not be anticipated. At the rear portion of the blanket the creep strain would be about 0.01% and not serious either. Radiation-induced stress relaxation at the vacuum vessel is only several per cent during the lifetime. At the rear portion of the blanket, on the other hand, the relaxation could be of the order of 10% and should not be completely neglected.

Nagakawa, Johsei

1998-10-01

413

Thermal annealing of radiation damaged titanite  

SciTech Connect

Radiogenic impurities of 400 to 800 ppm U and Th in titanite, CaTiSiO{sub 5}, lead to moderate radiation damage ({approx}1.5 {times} 10{sup 18} {alpha}-decay events/g) and therefore to partial amorphization ({approx}30%). Powder X-ray diffraction on such damaged titanite from the Cardiff locality in Canada shows that two modifications of the crystalline material coexist. Both modifications are structurally {beta} phase but differ systematically in their lattice parameters and also in their chemical composition. One modification exhibits strong particle size broadening in X-ray diffraction patterns, whereas it is almost unstrained with respect to fully annealed titanite. The other modification shows large strain broadening and increased specific volume (about 3%) due to a high concentration of defects. The unstrained modification consists of small nucleation centers in the damaged material, and it grows when the sample is annealed. At annealing temperatures above 823 K, this modification dominates rapidly and replaces the strained titanite. The results of Rietveld refinement of the annealed samples and of the time evolution of isothermal annealing studies are discussed. The analysis of volume strain and of structural strain resulting from the peak profiles suggests a temperature-dependent activation energy for the recrystallization process, with E{sub A} {approx} 380 kJ/mol at T > 873 K and E{sub A} {approx} 500 kJ/mol at temperatures 773 K < T < 873 K.

Chrosch, J.; Colombo, M.; Malcherek, T.; Salje, E.K.H. [Univ. of Cambridge (United Kingdom). Dept. of Earth Sciences; Groat, L.A. [Univ. of British Columbia, Vancouver (Canada). Dept. of Earth and Ocean Sciences; Bismayer, U. [Univ. Hamburg (Germany). Mineralogisch-Petrographisches Inst.

1998-09-01

414

Reduce costs with vacuum excavation  

SciTech Connect

Although vacuum excavation equipment and methods are in their infancy, this developing technology offers tremendous promise for the future. The author explains Brooklyn Union Gas Co.'s experience with five vacuum trucks and the procedures that are used. In recent years, the higher cost of natural gas has increased the need for gas utilities to reduce their operating expenses. One way, which has been successful at Brooklyn Union Gas, is the use of vacuum excavation. Although vacuum excavation equipment and techniques are in their infancy, this developing technology offers substantial savings today and tremendous promise for the future. Brooklyn Union started its vacuum digging program by locating keyhole cutoffs--small surface openings ranging from 1 ft by 1 ft to 1 1/2 ft by 1 1/2 ft (0.3 m to 0.45 m square). It is no easy task to accurately locate a service that was installed 60 years ago. Reading the street indications, locating an existing curb valve or repair opening, gaining access to the building, making a physical lineup, and using an M-scope, plus any other tools available, have produced a high success rate.

Vitale, S.A.

1983-09-01

415

Vacuum heat treatment effect on the thermophysical properties of BSCCO system  

NASA Astrophysics Data System (ADS)

Vacuum heat treatment effects at 850 C for (3, 6, 9 and 12 h) on the crystalline structure and superconducting, as well as on the mechanical properties of Bi 4Sr 3Ca 3Cu 6O x (BSCCO) have been studied. The highest critical transition temperature Tc 102 K was achieved at annealing time tann = 9 h. This maximum value is attributed to movement of excess oxygen from annealed sample. Phase examination by X-ray diffraction (XRD) revealed that the gradual formation of the high- Tc phase (2 2 2 3) due to the prolongation of annealing time up to 9 h. Thereafter, the high- Tc phase starts degrading and Tc reduces. The distortion of the 2 2 2 3 phase is suggested by the broadening of the different XRD peaks. Also, at the same above annealing time (9 h), SEM observation shows good quality plate-like crystal with relatively oriented. On the other hand, the Vickers microhardness (VHN) measurements was found to be dependent on the annealing conditions, a tremendously increase of VHN value 1.92 GPa (0.25 N) at tann = 9 h. This substantial increase is ascribed to improvement of the thermal conduction and stabilization of temperature distribution between superconducting grains.

Khalil, S. M.; Ahmed, A. M.

2007-02-01

416

Hydrogen Annealing Of Single-Crystal Superalloys  

NASA Technical Reports Server (NTRS)

Annealing at temperature equal to or greater than 2,200 degrees F in atmosphere of hydrogen found to increase ability of single-crystal superalloys to resist oxidation when subsequently exposed to oxidizing atmospheres at temperatures almost as high. Supperalloys in question are principal constituents of hot-stage airfoils (blades) in aircraft and ground-based turbine engines; also used in other high-temperature applications like chemical-processing plants, coal-gasification plants, petrochemical refineries, and boilers. Hydrogen anneal provides resistance to oxidation without decreasing fatigue strength and without need for coating or reactive sulfur-gettering constituents. In comparison with coating, hydrogen annealing costs less. Benefits extend to stainless steels, nickel/chromium, and nickel-base alloys, subject to same scale-adhesion and oxidation-resistance considerations, except that scale is chromia instead of alumina.

Smialek, James L.; Schaeffer, John C.; Murphy, Wendy

1995-01-01

417

Control of KEKB vacuum system  

NASA Astrophysics Data System (ADS)

In a vacuum system of the KEKB accelerator that is a two ring electron-positron collider, there are nearly 10,000 control points. A large number of vacuum related components should be controlled and/or monitored at the rings and the beam transport line from the linac. Those component hardwares are connected to their sub-interfaces such as ADC interfaced by devices of CAMAC, RS-232C, GP-IB, and programmable logic controller (PLC) via GP-IB. The all device interfaces are controlled with newly developed softwares based on EPICS (experimental physics industrial control system) and single board equipment control computers through a high speed network using a UNIX-based workstation with X-terminals or emulators as operator consoles. The control points of the hardware for the vacuum system have been successfully implemented for monitor, control and data acquisition after the commissioning for 8 months utilizing EPICS software.

Kato, S.; Kanazawa, K.; Suetsugu, Y.; Hisamatsu, H.; Shimamoto, M.; Sato, M.; Shirai, M.; Takagi, M.

2001-01-01

418

Heavy ion microbeam vacuum requirements  

NASA Astrophysics Data System (ADS)

Transport of heavy ions through an ion microbeam focusing system can be affected by insufficient vacuum within the beam transport tube. Due to interactions of heavy ions with atoms of residual gas in the vacuum tube of a microbeam facility, the angular, lateral and energy spreading of an ion beam increases prior to focusing, creating a beam halo. This beam halo can produce undesirable effects in some applications of ion microbeam techniques. In order to model this effect, the ion beam angular spread in residual gas has been approximated by Sigmund's theoretical predictions for small-angle ion multiple scattering (MS), while ion energy loss straggling distributions have been applied for studying the energy spread. The extent of the beam halo has been estimated by combining the results of these calculations with ion optics calculations. Recommendations concerning microbeam focusing due to the vacuum conditions are given for different heavy ions in the MeV energy range.

Tadi?, T.; Jaki?, M.

2009-06-01

419

Gravity-Induced Vacuum Dominance  

SciTech Connect

It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications.

Lima, William C. C.; Vanzella, Daniel A. T. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, CEP 15980-900, Sao Carlos, SP (Brazil)

2010-04-23

420

Gravity-induced vacuum dominance.  

PubMed

It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications. PMID:20482039

Lima, William C C; Vanzella, Daniel A T

2010-04-23

421

Mathematics needed for Introduction to Transport Phenomena  

NSDL National Science Digital Library

A collection of math problems based on skills needed to successfully complete homework problems in an introductory course in Transport Phenomena. These problems do not introduce any new material for those who have taken Freshman Calculus classes and a sophomore level Differential Equations class. At Purdue University in the required Transport Phenomena course for MSE undergrads (MSE 340), I give a problem set like this the first day of classes in order to make clear the level of mathematical skill needed for the rest of the semester. I have found that it reduces difficulties with math later in the semester, allowing the students to focus on the transport phenomena.

Krane, Matthew J.

2007-10-12

422

Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings  

NASA Astrophysics Data System (ADS)

Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si 3N 4, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 C has a similar friction coefficient to the as-deposited coating.

Xie, Z. W.; Wang, L. P.; Wang, X. F.; Huang, L.; Lu, Y.; Yan, J. C.

2011-11-01

423

Annealing induced changes in ternary nanostructured ZnxCd1-xSe thin films: structure and morphology  

NASA Astrophysics Data System (ADS)

Single layers of ZnxCd1-xSe with various compositions (x = 0.39, 0.59 and 0.8) were prepared by thermal vacuum evaporation at room substrate temperature. Consecutive deposition of small portions of ZnSe and CdSe with equivalent thickness of 0.12 or 0.37 nm was applied. X-ray diffraction and atomic force microscopy measurements were applied to explore the evolution of the crystal structure, microstructure, composition and surface morphology upon furnace annealing at 200 C and 400 C in an inert atmosphere. It has been found that as-deposited films were nanocrystalline with a grain size of around 10 nm and cubic structure. Upon annealing the size increased approximately three times and the cubic structure was preserved; no appearance of wurtzite phase was observed. It has been also ascertained that annealing caused significant reduction of the film surface roughness. Atomic force microscopy phase images revealed existence of a second phase on the surface of as-deposited films which disappeared after annealing. The effect of the preparation conditions on the film properties and annealing induced changes is discussed.

Bineva, I.; Nesheva, D.; Pejova, B.; Mineva, M.; Levi, Z.; Aneva, Z.

2012-12-01

424

Effect of annealing temperature on microstructure, hardness and adhesion properties of TiSi xN y superhard coatings  

NASA Astrophysics Data System (ADS)

A series of TiSi xN y superhard coatings with different Si contents were prepared on M42 steel substrates using two Ti and two Si targets by reactive magnetron sputtering at 500 C. These samples were subsequently vacuum-annealed at 500, 600, 700, 800 and 900 C, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microindenter, Rockwell hardness tester and scratch tester were applied to investigate the microstructure, phase configuration, hardness and adhesion properties of as-deposited and annealed samples. The results indicated that there were two bonds, TiN and Si 3N 4, in all presently deposited TiSi xN y thin films, that structure was nanocomposite of nanocrystalline (nc-) TiN embedded into amorphous Si 3N 4 matrices. Annealing treatment below 900 C played a little role in microstructure and hardness of the coatings although it greatly affected those of steel substrates. The film-substrate adhesion strength was slightly increased, followed by an abrupt decrease with increasing annealing temperature. Its value got to the maximum at 600 C. Annealing had little effect on the friction coefficient with its value varying in the range of 0.39-0.40.

Lu, Y. H.; Wang, J. P.; Tao, S. L.; Zhou, Z. F.

2011-05-01

425

Dispersion of laser droplets using H+ ions and annealing effect on pulsed laser deposited nickel ferrite thin films  

NASA Astrophysics Data System (ADS)

Nickel ferrite thin films were deposited by a pulsed laser deposition (PLD) technique on silicon substrate at room temperature in a vacuum of 510-5 mbar. The films were subjected to different annealing temperatures from 300-900C and were also exposed to single shot energetic hydrogen ions using a Dense Plasma Focus (DPF) device. The changes induced in the films exposed at different distances from the top of the anode were investigated. The structural, morphological and magnetic properties of the annealed and exposed samples were investigated. X-ray diffraction (XRD) studies reveal the presence of a single phase of nickel ferrite after annealing. SEM micrographs indicate an increase in the grain size, both on annealing as well as on exposure to hydrogen ions. Annealing and hydrogen ion irradiation induced an enhancement in the magnetic moments. Laser droplets which are inherent in films deposited by laser ablation were found to be dispersed as a result of single shot hydrogen ion irradiation from the DPF.

Malik, Rakesh; Annapoorni, S.; Lamba, S.; Mahmood, S.; Rawat, R. S.

2011-10-01

426

THE EFFECT OF POST-IRRADATION ANNEALING ON STACKING FAULT TETRAHEDRA IN NEUTRON-IRRADIATED OFHC COPPER  

SciTech Connect

Two irradiation experiments have been completed wherein two sets of tensile specimens of OFHC copper were irradiated with fission neutrons, one set at 200 degrees C and the other at 250 degrees C. Post-irradiation annealing in vacuum was then used to evaluate the change in the defect microstructure, including vacancy-type SFT, voids, and dislocation loops. Individual samples within each set were given one annealing exposure at 300, 350, 400, 450, 500, or 550 degrees C for 2 hours. The fine-scale defect microstructure was characterized by transmission electron microscopy (TEM) to compare the defect size and spatial distribution at each annealing temperature and reference the results to that measured in the as-irradiated condition. Based on the change in the SFT size distributions, post-irradiation annealing led to a preferential removal of the smaller sized SFT, but did not lead to a general coarsening as might be expected from an Oswald ripening scenario. The issue of whether the SFT produced during irradiation are all structurally perfect is still being investigated at the time of this report, however, the images of the SFT appeared more perfect after annealing at 300 degrees C and higher. Further analysis is being performed to determine whether intermediate stages of SFT formation exist in the as-irradiated condition.

Edwards, Danny J.; Singh, Bachu N.; Eldrup, M.

2003-09-03

427

Parameterization of annealing kinetics in pharmaceutical glasses.  

PubMed

Numerical simulations indicate that neglecting the canonical nonlinearity of glassy-state annealing kinetics in pharmaceutical (and other) glasses leads to good KWW fits to the dependence of enthalpy on annealing time, but with spurious KWW parameters that are affected by nonlinearity. A simplified treatment of nonlinearity that uses the Struik shift factor is found to be a useful approximation for these analyses, and can account for previously reported differences between linear and nonlinear KWW parameters (Kawakami K, Pikal MJ. 2005. J Pharm Sci 94:948-965). PMID:23661359

Hodge, Ian M

2013-07-01

428

Quantum annealing in a kinetically constrained system.  

PubMed

Classical and quantum annealing is discussed in the case of a generalized kinetically constrained model, where the relaxation dynamics of a system with trivial ground state is retarded by the appearance of energy barriers in the relaxation path, following a local kinetic rule. Effectiveness of thermal and quantum fluctuations in overcoming these kinetic barriers to reach the ground state are studied. It has been shown that for certain barrier characteristics, quantum annealing might by far surpass its thermal counter part in reaching the ground state faster. PMID:16196745

Das, Arnab; Chakrabarti, Bikas K; Stinchcombe, Robin B

2005-08-01

429

Work Hardening and Annealing of Copper  

NSDL National Science Digital Library

This activity will demonstrate the process of work hardening and annealing of a copper. Students will get the opportunity to see the hardening of metal by deformation, experience the process of work hardening, explain the effects of work hardening in metals and experience property changes affected by annealing. This activity would be appropriate for grades 4 through high school and college level, with each age group gaining different educational benefits. Around 60 minutes is required for the demonstration. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

Stoebe, Thomas G.

2012-10-18

430

Rock melting tool with annealer section  

DOEpatents

A rock melting penetrator is provided with an afterbody that rapidly cools a molten geological structure formed around the melting tip of the penetrator to the glass transition temperature for the surrounding molten glass-like material. An annealing afterbody then cools the glass slowly from the glass transition temperature through the annealing temperature range to form a solid self-supporting glass casing. This allows thermally induced strains to relax by viscous deformations as the molten glass cools and prevents fracturing of the resulting glass liner. The quality of the glass lining is improved, along with its ability to provide a rigid impermeable casing in unstable rock formations.

Bussod, Gilles Y. (Santa Fe, NM); Dick, Aaron J. (Oakland, CA); Cort, George E. (Montrose, CO)

1998-01-01

431

Cooperativity in the annealing of DNA origamis  

NASA Astrophysics Data System (ADS)

DNA based nanostructures built on a long single stranded DNA scaffold, known as DNA origamis, offer the possibility to organize various molecules at the nanometer scale in one pot experiments. The folding of the scaffold is guaranteed by the presence of short, single stranded DNA sequences (staples), that hold together separate regions of the scaffold. In this paper, we modelize the annealing-melting properties of these DNA constructions. The model captures important features such as the hysteresis between melting and annealing, as well as the dependence upon the topology of the scaffold. We show that cooperativity between staples is critical to quantitatively explain the folding process of DNA origamis.

Arbona, Jean-Michel; Aim, Jean-Pierre; Elezgaray, Juan

2013-01-01

432

Vacuum Plasma Spraying Replaces Electrodeposition  

NASA Technical Reports Server (NTRS)

Vacuum plasma spraying used to fabricate large parts with complicated contours and inner structures, without uninspectable welds. Reduces time, and expense of fabrication. Wall of combustion chamber built up inside of outer nickel-alloy jacket by plasma spraying. Particles of metal sprayed partially melted in plasma gun and thrown at supersonic speed toward deposition surface. Vacuum plasma-spray produces stronger bond between the grooves and covering layer completing channels and wall of combustion chamber. In tests, bond withstood pressure of 20 kpsi, three times allowable limit by old method.

Holmes, Richard R.; Power, Chris; Burns, David H.; Daniel, Ron; Mckechnie, Timothy N.

1992-01-01

433

Relativistic invariance of the vacuum  

NASA Astrophysics Data System (ADS)

Relativistic invariance of the vacuum is (or follows from) one of the Wightman axioms, which is commonly believed to be true. Without these axioms, here we present a direct and general proof of continuous relativistic invariance of all real-time vacuum correlations of fields, not only scattering (forward in time), based on closed time path formalism. The only assumptions are basic principles of relativistic quantum field theories: the relativistic invariance of the Lagrangian, of the form including known interactions (electromagnetic, weak and strong), and standard rules of quantization. The proof is in principle perturbative leaving a possibility of spontaneous violation of invariance. Time symmetry is, however, manifestly violated.

Bednorz, Adam

2013-12-01

434

Method for vacuum fusion bonding  

DOEpatents

An improved vacuum fusion bonding structure and process for aligned bonding of large area glass plates, patterned with microchannels and access holes and slots, for elevated glass fusion temperatures. Vacuum pumpout of all components is through the bottom platform which yields an untouched, defect free top surface which greatly improves optical access through this smooth surface. Also, a completely non-adherent interlayer, such as graphite, with alignment and location features is located between the main steel platform and the glass plate pair, which makes large improvements in quality, yield, and ease of use, and enables aligned bonding of very large glass structures.

Ackler, Harold D. (Sunnyvale, CA); Swierkowski, Stefan P. (Livermore, CA); Tarte, Lisa A. (Livermore, CA); Hicks, Randall K. (Stockton, CA)

2001-01-01

435

Ridge formation and removal via annealing in exfoliated graphene.  

PubMed

It is well known that graphene is a very promising material due to its excellent physical, chemical, and thermal properties. Previously, ridges in graphene on a substrate were found in epitaxial graphene on a SiC substrate. It was found in this study that ridges can be made on a graphene layer via mechanical exfoliation on a sapphire substrate, and that ridges can be created or removed through heating and cooling. Due to the difference of the thermal-expansion coefficients of the substrate and graphene, it can be said that thermal cycling causes compressive strain, which is released by forming ridges. Annealing was carried out in a vacuum chamber within the pressure range of 10(-3)-10(-6) Torr and at 900-1100 degrees C. To analyze the shapes and mechanical properties of the ridges, Raman spectroscopy and AFM measurement were performed. It was found that the ridges can be extended by defect as a nucleation center, and the graphene layer can be folded along the preexisting ridge during heating and cooling. PMID:22121637

Han, Sang A; Choi, In Sung; An, Hyo Sub; Lee, Hyunsoo; Yong, Hyeon Deuk; Lee, Sangwook; Jung, Jongwan; Lee, Nae Sung; Seo, Yongho

2011-07-01

436

Crystal Nucleation in Plasma Deposited Dlc Coatings during Annealing  

NASA Astrophysics Data System (ADS)

Diamond-like carbon (DLC) films, hard carbon coatings, with unique physical and mechanical properties which approach those of natural diamond, such as high hardness, low coefficient of friction and chemical inertness. In several applications, heavy loads and high friction forces are generated and lead to local temperature increase. In such cases these coatings must be thermal stable and with enhanced high temperature oxidation resistance in order to be good candidates for wear protection of metallic components. In the present study a radio frequency plasma deposition system was used for the deposition of 2 ?m-thick amorphous DLC coatings onto AISI D2 substrates. The as deposited DLC covered samples were dense, homogeneous and well bonded to the substrate, while no cracks were observed. In order to study the thermal stability of the coatings' DLC nature, in-situ Transmission Electron Microscopic (TEM) observations were carried out during slow annealing of the specimen in the microscope vacuum chamber, as well as thermo-gravimetric (TG) measurements in argon atmosphere, up to 800 C. The first crystallites appeared within the DLC amorphous matrix at about 450 C as surface crystallization, while the mass crystallization started at 600 C as the TG measurements indicated. Finally, the nucleation was completed at 700 C. The oxidation results, performed from ambient temperature up to 1000 C, showed that DLC covered coupons are remarkably resistant as their mass gain was significantly lower than that of the uncovered substrates.

Chaliampalias, D.; Pavlidou, E.; Psyllaki, P.; Chrissafis, K.; Vourlias, G.

2010-01-01

437

Vacuum System of the Electron Storage Ring  

NASA Astrophysics Data System (ADS)

The lecturer expects the students to know the fundamentals of vacuum physics and vacuum engineering, that is, kinetic theory of gases, pressure units, gas flow regimes, conductance for aperture and tubes, vacuum pumps, vacuum components, and vacuum system materials1, 2. This knowledge is helpful for the students at this school to understand the vacuum system for the electron storage ring. The lecture includes the following subjects. 1. Beam Lifetime and Vacuum Pressure in the Electron Storage Ring 2. Photon Generation and Gas Load by Photodesorption 3. Pumping Speed and Conductance of Vacuum Duct 4. Pressure Distribution along the Vacuum Duct 5. Practical System Design of the Electron Storage Ring 6. Example of an Electron Storage Ring; Antechamber Structure

Kobayashi, Masanori

2002-02-01

438

Surface Chemistry, Friction, and Wear Properties of Untreated and Laser-Annealed Surfaces of Pulsed-Laser-Deposited WS(sub 2) Coatings  

NASA Technical Reports Server (NTRS)

An investigation was conducted to examine the surface chemistry, friction, and wear behavior of untreated and annealed tungsten disulfide (WS2) coatings in sliding contact with a 6-mm-diameter 440C stainless-steel ball. The WS2 coatings and annealing were performed using the pulsed-laser-deposition technique. All sliding friction experiments were conducted with a load of 0.98 N (100 g), an average Hertzian contact pressure of 0.44 GPa, and a constant rotating speed of 120 rpm. The sliding velocity ranged from 31 to 107 mm/s because of the range of wear track radii involved in the experiments. The experiment was performed at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7X(exp -10) Pa), dry nitrogen (relative humidity, less than 1 percent), and humid air (relative humidity, 15 to 40 percent). Analytical techniques, including scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), x-ray photo electron spectroscopy (XPS), surface profilometry, and Vickers hardness testing, were used to characterize the tribological surfaces of WS2 coatings. The results of the investigation indicate that the laser annealing decreased the wear of a WS2 coating in an ultrahigh vacuum. The wear rate was reduced by a factor of 30. Thus, the laser annealing increased the wear life and resistance of the WS2 coating. The annealed WS 2 coating had a low coefficient of friction (less than O.1) and a low wear rate ((10(exp -7) mm(exp 3)/N-m)) both of which are favorable in an ultrahigh vacuum.

Miyoshi, Kazuhisa; Wheeler, Donald R.; Zabinski, Jeffrey S.

1996-01-01

439

Electrical Phenomena in Biological Membranes: A Symposium.  

National Technical Information Service (NTIS)

Contents: Biological Systems - General Properties of Biological Membranes, Red Blood Cells, Oscillatory Phenomena in Plant Cells, Chemotaxis, Nerve, Post-Synaptic Membrane, Visual Transduction and Energy Conversion by Rhodopsins; Non-Viable Systems - Mono...

J. B. Bateman

1977-01-01

440

Microbiologically Influenced Corrosion: Global Phenomena, Local Mechanisms.  

National Technical Information Service (NTIS)

Much of the on-going research in microbiologically influenced corrosion (MIC) is directed al identification of unifying mechanisms for global observations of MIC-related phenomena, e.g. ennoblement of passive alloys and corrosion of carbon steel pilings. ...

B. Little J. Lee R. Ray

2011-01-01

441

Transient Phenomena in Asynchronous Motor Drive.  

National Technical Information Service (NTIS)

Transient torques of a motor drive cause torsional stresses in the shaft. Motor is constructed to withstand these torques. In construction of couplings, shaft and drive these torques have to be taken into consideration, too. Transient phenomena are simula...

R. Hirvonen

1989-01-01

442

Bibliography on Electrostatic Phenomena in Aerosol Dissemination.  

National Technical Information Service (NTIS)

The bibliography represents a survey of published information relevant to the manner in which electrostatic phenomena might influence dissemination of chemical warfare agents, covering both the open literature and reports of government-sponsored research....

D. E. Blake C. E. Lapple

1965-01-01

443

Mysterious Phenomena of the Human Psyche.  

National Technical Information Service (NTIS)

Contents: Mysterious psychic phenomena as a source of superstition; Sleep and dreams; Hypnosis and suggestion; Suggestion and autosuggestion in the waking state; Automatic movement; Is there a 'mental radio'; What can be said about 'extrasensory perceptio...

L. L. Vasilev

1967-01-01

444

Canister storage building natural phenomena design loads  

SciTech Connect

This document presents natural phenomena hazard (NPH) loads for use in the design and construction of the Canister Storage Building (CSB), which will be located in the 200 East Area of the Hanford Site.

Tallman, A.M.

1996-02-01

445

Second DOE natural phenomena hazards mitigation conference  

SciTech Connect

This conference has been organized into ten presentation sessions which include an overview of the DOE Natural Phenomena Guidelines, Seismic Analysis, Seismic Design, Modifying Existing Facilities, DOE Orders, Codes, and Standards (2 sessions), Seismic Hazard (2 sessions), and Probabilistic Risk Assessment (2 sessions). Two poster sessions were also included in the program to provide a different forum for communication of ideas. Over the past fourteen years, Lawrence Livermore National Laboratory, Nuclear Systems Safety Program, has been working with the US Department of Energy, Office of Safety Appraisals and their predecessors in the area of natural phenomena hazards. During this time we have developed seismic, extreme wind/tornado, and flood hazard models for DOE sites in the United States. Guidelines for designing and evaluating DOE facilities for natural phenomena have been developed and are in interim use throughout the DOE community. A series of state-of-the practice manuals have also been developed to aid the designers. All of this material is listed in the Natural Phenomena Hazards Bibliography included in these proceedings. This conference provides a mechanism to disseminate current information on natural phenomena hazards and their mitigation. It provides an opportunity to bring together members of the DOE community to discuss current projects, to share information, and to hear practicing members of the structural engineering community discuss their experiences from past natural phenomena, future trends, and any changes to building codes. Each paper or poster presented is included in these proceedings. We have also included material related to the luncheon and dinner talks.

Not Available

1989-01-01

446

Vacuum ultraviolet photochemistry of polymers  

Microsoft Academic Search

The interaction of vacuum UV radiation (wavelength range from 1 to 200 nm) with polymers is interesting for fundamental and applied sciences. This interest is stimulated by various reasons:Wide applications of polymeric materials in semiconductor technology, where they are used as photoresist materials in combination with VUV light sources (lasers, excimer lamps, synchrotron radiation and others).Polymers are widely used as

Vladimir Skurat

2003-01-01

447

Hadrons in Vacuum and Matter  

Microsoft Academic Search

In the first part of this thesis, we investigate the correlators and form factors of hadrons in vacuum viewed as a dilute gas of instantons and antiinstantons. Relying heavily on approximate bosonization techniques in four dimensions, we construct an effective action for constituent quarks in interaction with mesons and glueballs. The effective action is then used to study various meson,

Mourad Kacir

1995-01-01

448

Vacuum Head Removes Sanding Dust  

NASA Technical Reports Server (NTRS)

Vacuum sander prevents sanding dust from entering a work area, since dust particles are drawn off as quickly as they are produced. Tool is useful where dust presents health hazards, interferes with such processes as semiconductor manufacture, or could destroy wet paint or varnish finishes. Could be used to sand such materials as lead paint.

Bengle, C. G.; Holt, J. W.

1982-01-01

449

Vacuum barrier for excimer lasers  

DOEpatents

A barrier for separating the vacuum area of a diode from the pressurized gas area of an excimer laser. The barrier is a composite material comprising layers of a metal such as copper, along with layers of polyimide, and a matrix of graphite fiber yarns impregnated with epoxy. The barrier is stronger than conventional foil barriers, and allows greater electron throughput. 3 figs.

Shurter, R.P.

1992-09-15

450

Vacuum insulating window and reflector  

Microsoft Academic Search

A vacuum insulating window and reflector is described for controlling the heat gain and loss efficiency of an enclosed space and structure, which consists of: (a) a visually transparent panel having a substantially evacuated hollow cavity; (b) at least one adjustable vane contained within the hollow cavity; (c) a highly reflective metallic nonferrous surface on the at least one adjustable

1986-01-01

451

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process.

Dr. M.A. Ebadian

2000-01-13

452

Vacuum forming of thermoplastic foam  

Microsoft Academic Search

The process of thermoforming of foam sheet is analyzed using both finite element modeling and experiments. A simple constitutive model for finite tensile deformations of closed cellular material around its glass transition temperature is proposed, starting from well-known results from Gibson and Ashby (1988). The model is implemented in a finite element code and applied in isothermal vacuum forming simulations.

Remko Akkerman; Ruud Pronk

1999-01-01

453

SHINE Vacuum Pump Test Verification.  

National Technical Information Service (NTIS)

The purpose of the pump testing is two-fold: (1) obtain baseline vacuum pump characteristics for an alternate (i.e. Normetex replacement) pump intended for use in tritium service; and (2) verify that low pressure hydrogen gas can be ransported over distan...

B. Peters G. A. Morgan

2013-01-01

454

High Temperature Ultrahigh Vacuum Valves.  

National Technical Information Service (NTIS)

All-metal valves heatable up to 300 to 400 C in closed and open position were developed for handling aggressive gases such as UF6 in high vacuum technology. Sealing aspects of valves with large nominal width, such as transfer valve NW 150 and corner valve...

W. Baechler G. Jokisch H. P. Kabelitz K. Teutenberg

1976-01-01

455

Plates for vacuum thermal fusion  

DOEpatents

A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

Davidson, James C. (Livermore, CA); Balch, Joseph W. (Livermore, CA)

2002-01-01

456

Vacuum Flushing of Sewer Solids  

EPA Science Inventory

The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

457

Vacuum-insulated catalytic converter  

DOEpatents

A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

Benson, David K. (Golden, CO)

2001-01-01

458

Degassing procedure for ultrahigh vacuum  

NASA Technical Reports Server (NTRS)

Calculations based on diffusion coefficients and degassing rates for stainless-steel vacuum chambers indicate that baking at lower temperatures for longer periods give lower ultimate pressures than rapid baking at high temperatures. Process could reduce pressures in chambers for particle accelerators, fusion reactors, material research, and other applications.

Moore, B. C.

1979-01-01

459

A vacuum ultraviolet spectrophotometric system  

NASA Technical Reports Server (NTRS)

The development of a vacuum ultraviolet spectrophotometric system for measuring transmittance and reflectance at variable angles is presented. Using various detectors and sources, the spectrophotometric system has been used for wavelengths from 80 nm to 300 nm with optical components up to 80 mm in diameter. The capability exists to make measurements through the visible range.

Spann, James F.; Keffer, Charles E.; Zukic, Muamer

1993-01-01

460

Vacuum arc remelting: An overview  

NASA Astrophysics Data System (ADS)

Vacuum arc remelting (VAR) is a casting process for producing uniform ingots. This paper discusses: arc physics and behavior, metal transfer and electrode gap measurement, boundary conditions on crucible wall, and pool dynamics and macrosegregation. Materials discussed are Inconel 718 and U-6% Nb alloy.

Zanner, F. J.; Bertram, L. A.

1985-08-01

461

Vacuum barrier for excimer lasers  

DOEpatents

A barrier for separating the vacuum area of a diode from the pressurized gas area of an excimer laser. The barrier is a composite material comprising layers of a metal such as copper, along with layers of polyimide, and a matrix of graphite fiber yarns impregnated with epoxy. The barrier is stronger than conventional foil barriers, and allows greater electron throughput.

Shurter, Roger P. (Jemez Springs, NM)

1992-01-01

462

Vacuum Cut-off Switch.  

National Technical Information Service (NTIS)

The vacuum cut-off switch is shown in a system including an evacuation chamber, a pump, an electric motor, a battery and conduits connecting the components. A pressure responsive detecting device is associated with the switch for controlling the operation...

J. E. Coyle

1964-01-01

463

Graphene annealing: how clean can it be?  

PubMed

Surface contamination by polymer residues has long been a critical problem in probing graphene's intrinsic properties and in using graphene for unique applications in surface chemistry, biotechnology, and ultrahigh speed electronics. Poly(methyl methacrylate) (PMMA) is a macromolecule commonly used for graphene transfer and device processing, leaving a thin layer of residue to be empirically cleaned by annealing. Here we report on a systematic study of PMMA decomposition on graphene and of its impact on graphene's intrinsic properties using transmission electron microscopy (TEM) in combination with Raman spectroscopy. TEM images revealed that the physisorbed PMMA proceeds in two steps of weight loss in annealing and cannot be removed entirely at a graphene susceptible temperature before breaking. Raman analysis shows a remarkable blue-shift of the 2D mode after annealing, implying an anneal-induced band structure modulation in graphene with defects. Calculations using density functional theory show that local rehybridization of carbons from sp(2) to sp(3) on graphene defects may occur in the random scission of polymer chains and account for the blue-shift of the Raman 2D mode. PMID:22149394

Lin, Yung-Chang; Lu, Chun-Chieh; Yeh, Chao-Huei; Jin, Chuanhong; Suenaga, Kazu; Chiu, Po-Wen

2012-01-11

464

Annealing of gold nanostructures sputtered on polytetrafluoroethylene  

PubMed Central

Gold nanolayers sputtered on polytetrafluoroethylene (PTFE) surface and their changes induced by post-deposition annealing at 100C to 300C are studied. Changes in surface morphology and roughness are examined by atomic force microscopy, electrical sheet resistance by two point technique, zeta potential by electrokinetic analysis and chemical composition by X-ray photoelectron spectroscopy (XPS) in dependence on the gold layer thickness. Transition from discontinuous to continuous gold coverage takes place at the layer thicknesses 10 to 15 nm and this threshold remains practically unchanged after the annealing at the temperatures below 200C. The annealing at 300C, however, leads to significant rearrangement of the gold layer and the transition threshold increases to 70 nm. Significant carbon contamination and the presence of oxidized structures on gold-coated samples are observed in XPS spectra. Gold coating leads to a decrease in the sample surface roughness. Annealing at 300C of pristine PTFE and gold-coated PTFE results in significant increase of the sample surface roughness.

2011-01-01

465

High mobility annealing of Transparent Conductive Oxides  

NASA Astrophysics Data System (ADS)

To improve electrical properties a high temperature annealing treatment was applied to several transparent conductive oxides (TCO), namely tin doped indium oxide (ITO), Ga- or Al- doped ZnO (ZnO:Al/Ga), ion beam assisted deposited (IBAD) ZnO:Ga and Ga doped zinc magnesium oxide (ZnMgO:Ga). All these films were grown by magnetron sputtering. During the annealing process all TCO films were capped with 50 nm of amorphous silicon in order to protect the films from environmental impact. Increase in mobility up to 72 cm2/Vs and low resistivity of 1.6 10-4 ?cm was achieved for ZnO:Al after annealing at 650C for 24 h. Independent of the deposition conditions and doping or alloying material almost all ZnO based films show a consistent improvement in mobility. Also for ITO films a decrease in resistivity with partially improved mobility was found after annealing. However, not all ITO films show consistent improvement, but carrier density above 1021 cm-3 while ZnO films show no clear trend for carrier density but a remarkable increase in mobility. Thus we propose the healing of defects and the activation of donors to be most significant effects for ZnO and ITO films, respectively.

Warzecha, M.; Owen, J. I.; Wimmer, M.; Ruske, F.; Hotovy, J.; Hpkes, J.

2012-04-01

466

Annealing kinetics of thin permalloy films  

SciTech Connect

Low-temperature (250-397/sup 0/C) annealing was found to cause a large decrease in the resistivity of radio-frequency sputter-deposited thin (less than or equal to500 A) Permalloy films. A transmission electron microscope was used to investigate a probable microstructural change occurring during the annealing. It was found that the low-temperature annealing induced considerable grain growth in these films. Furthermore, an electron diffraction analysis has shown that this grain growth was accompanied by the formation of the ordered phase (Ni/sub 3/Fe). The use of dark-field imaging revealed that the small ordered region appears to be formed around the disordered regions via a grain-boundary diffusion mechanism. The observed resistivity decrease was proposed to occur by the structural ordering as a result of the annealing. The measured activation energy for this process was 0.72 eV. This activation energy appears to be associated with the grain boundary migration of excess vacancies trapped during film formation.

Butherus, A.D.; Nakahara, S.

1985-07-01

467

Morphological changes during annealing of polyethylene nanocrystals.  

PubMed

Polymer crystals are metastable and exhibit morphological changes when being annealed. To observe morphological changes on molecular scales we started from small nanometer-sized crystals of highly folded long-chain polymers. Micron-sized stripes consisting of monolayers or stacks of several layers of flat-on oriented polyethylene nanocrystals were generated via evaporative dewetting from an aqueous dispersion. We followed the morphological changes in time and at progressively higher annealing temperatures by determining the topography and viscoelastic properties of such assemblies of nanocrystals using atomic force microscopy. Due to smallness and high surface-to-volume ratio of the nanocrystals, already at 75 C, i.e. about 60 degrees below the nominal melting point, the lateral size of the crystal coarsened. Intriguingly, this occurred without a noticeable reduction in the number of folds per polymer chain. Starting at around 110 C, chain folds were progressively removed leading to crystal thickening. At higher temperatures, but still below the melting point, prolonged annealing allowed for surface diffusion of molten polymers on the initially bare substrate, leading eventually to the disappearance of crystals. We compared these results to the behavior of the same nanocrystals annealed in an aqueous dispersion and to bulk samples. PMID:22430366

Basu, N; Osichow, A; Mecking, S; Reiter, G

2012-03-01

468

FRACTURE ROUGHNESS IN THE ANNEALED FUSE MODEL  

Microsoft Academic Search

We have studied the properties of fracture in an annealed fuse model, with focus on fracture roughness. The results are obtained via numerical simula- tion. We have found that neither H nor are universal quantities for the model. Both increase for increasing . The results indicate an asymptotic value close to 1 for H as ! 1. Fracture processes are

T. STRANDEN

2002-01-01

469

Deformation and annealing study of Nicraly  

NASA Technical Reports Server (NTRS)

Extensive experiments were carried out on the ODS alloy Nicraly, (an alloy prepared by mechanical alloying and consolidating a powder blend consisting of 16% chromium, 4% aluminum, 2-3% yttria, balance nickel), in efforts to develop methods of controlling the grain size and grain shape of the material. The experiments fell into two general categories: variations in the annealing parameters using the as-extruded material as it was received, and various thermomechanical processing schedules (various combinations of cold work and annealing). Success was achieved in gaining grain size and grain shape control by annealing of the as-extruded material. By proper selection of annealing temperature and cooling rates, the grain size of the as-received material was increased almost two orders of magnitude (from an average grain dimension of 0.023 mm to 1.668 mm) while the aspect ratio was increased by some 50% (from 20:1 to 30:1). No success was achieved in gaining significant control of the grain size and shape of the material by thermo-mechanical processing.

Trela, D. M.; Ebert, L. J.

1975-01-01

470

Irradiation and annealing effects in amorphous alloys  

SciTech Connect

The coercive force and the remnant magnetism were investigated as a function of temperature and post manufacture processing. A microcomputer based data acquisition system was developed to record and analyze the a-c hysteresis cycle as the amorphous materials undergo the phase transition from the ferromagnetic to the paramagnetic state. The coercive force is known to be a structure sensitive parameter and is shown to provide information of microstructural changes occurring. Materials of the composition Fe/sub x/Ni/sub 80-x/P/sub 14/B/sub 6/ were studied in the as-quenched state and then subjected to thermal annealing and irradiation with 2 MeV protons. Observations of structural relaxation as a function of thermal annealing temperature and time of anneal are presented. The structural relaxation observed as a result of thermal annealing appears to obey Ln t kinetics with an activation energy of 0.3-0.5 eV per atom. The Anderson two-level multiconfigurational model seems an appropriate explanation for the apparent irreversible reduction in the coercive force, and the observed reversible nature of the Curie temperature.

Hoover, D.S.

1986-01-01

471

Laser annealing of nanocrystalline gold nanowires.  

PubMed

The efficacy of laser annealing for the thermal annealing of nanocrystalline gold nanowires is evaluated. Continuous laser illumination at 532 nm, focused to a 0.5 ?m diameter spot, was rastered perpendicular to t